mm: fix exec activate_mm vs TLB shootdown and lazy tlb switching race

[linux/fpc-iii.git] / fs / nfs / nfs4proc.c

/*
 *  fs/nfs/nfs4proc.c
 *
 *  Client-side procedure declarations for NFSv4.
 *
 *  Copyright (c) 2002 The Regents of the University of Michigan.
 *  All rights reserved.
 *
 *  Kendrick Smith <kmsmith@umich.edu>
 *  Andy Adamson   <andros@umich.edu>
 *
 *  Redistribution and use in source and binary forms, with or without
 *  modification, are permitted provided that the following conditions
 *  are met:
 *
 *  1. Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *  2. Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in the
 *     documentation and/or other materials provided with the distribution.
 *  3. Neither the name of the University nor the names of its
 *     contributors may be used to endorse or promote products derived
 *     from this software without specific prior written permission.
 *
 *  THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
 *  WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
 *  MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 *  DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 *  FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 *  CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 *  SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
 *  BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 *  LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 *  NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 *  SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include <linux/mm.h>
#include <linux/delay.h>
#include <linux/errno.h>
#include <linux/string.h>
#include <linux/ratelimit.h>
#include <linux/printk.h>
#include <linux/slab.h>
#include <linux/sunrpc/clnt.h>
#include <linux/nfs.h>
#include <linux/nfs4.h>
#include <linux/nfs_fs.h>
#include <linux/nfs_page.h>
#include <linux/nfs_mount.h>
#include <linux/namei.h>
#include <linux/mount.h>
#include <linux/module.h>
#include <linux/xattr.h>
#include <linux/utsname.h>
#include <linux/freezer.h>

#include "nfs4_fs.h"
#include "delegation.h"
#include "internal.h"
#include "iostat.h"
#include "callback.h"
#include "pnfs.h"
#include "netns.h"
#include "nfs4idmap.h"
#include "nfs4session.h"
#include "fscache.h"

#include "nfs4trace.h"

#define NFSDBG_FACILITY         NFSDBG_PROC

#define NFS4_POLL_RETRY_MIN     (HZ/10)
#define NFS4_POLL_RETRY_MAX     (15*HZ)

/* file attributes which can be mapped to nfs attributes */
#define NFS4_VALID_ATTRS (ATTR_MODE \
        | ATTR_UID \
        | ATTR_GID \
        | ATTR_SIZE \
        | ATTR_ATIME \
        | ATTR_MTIME \
        | ATTR_CTIME \
        | ATTR_ATIME_SET \
        | ATTR_MTIME_SET)

struct nfs4_opendata;
static int _nfs4_proc_open(struct nfs4_opendata *data);
static int _nfs4_recover_proc_open(struct nfs4_opendata *data);
static int nfs4_do_fsinfo(struct nfs_server *, struct nfs_fh *, struct nfs_fsinfo *);
static void nfs_fixup_referral_attributes(struct nfs_fattr *fattr);
static int nfs4_proc_getattr(struct nfs_server *, struct nfs_fh *, struct nfs_fattr *, struct nfs4_label *label);
static int _nfs4_proc_getattr(struct nfs_server *server, struct nfs_fh *fhandle, struct nfs_fattr *fattr, struct nfs4_label *label);
static int nfs4_do_setattr(struct inode *inode, struct rpc_cred *cred,
                            struct nfs_fattr *fattr, struct iattr *sattr,
                            struct nfs_open_context *ctx, struct nfs4_label *ilabel,
                            struct nfs4_label *olabel);
#ifdef CONFIG_NFS_V4_1
static struct rpc_task *_nfs41_proc_sequence(struct nfs_client *clp,
                struct rpc_cred *cred,
                struct nfs4_slot *slot,
                bool is_privileged);
static int nfs41_test_stateid(struct nfs_server *, nfs4_stateid *,
                struct rpc_cred *);
static int nfs41_free_stateid(struct nfs_server *, const nfs4_stateid *,
                struct rpc_cred *, bool);
#endif

#ifdef CONFIG_NFS_V4_SECURITY_LABEL
static inline struct nfs4_label *
nfs4_label_init_security(struct inode *dir, struct dentry *dentry,
        struct iattr *sattr, struct nfs4_label *label)
{
        int err;

        if (label == NULL)
                return NULL;

        if (nfs_server_capable(dir, NFS_CAP_SECURITY_LABEL) == 0)
                return NULL;

        err = security_dentry_init_security(dentry, sattr->ia_mode,
                                &dentry->d_name, (void **)&label->label, &label->len);
        if (err == 0)
                return label;

        return NULL;
}
static inline void
nfs4_label_release_security(struct nfs4_label *label)
{
        if (label)
                security_release_secctx(label->label, label->len);
}
static inline u32 *nfs4_bitmask(struct nfs_server *server, struct nfs4_label *label)
{
        if (label)
                return server->attr_bitmask;

        return server->attr_bitmask_nl;
}
#else
static inline struct nfs4_label *
nfs4_label_init_security(struct inode *dir, struct dentry *dentry,
        struct iattr *sattr, struct nfs4_label *l)
{ return NULL; }
static inline void
nfs4_label_release_security(struct nfs4_label *label)
{ return; }
static inline u32 *
nfs4_bitmask(struct nfs_server *server, struct nfs4_label *label)
{ return server->attr_bitmask; }
#endif

/* Prevent leaks of NFSv4 errors into userland */
static int nfs4_map_errors(int err)
{
        if (err >= -1000)
                return err;
        switch (err) {
        case -NFS4ERR_RESOURCE:
        case -NFS4ERR_LAYOUTTRYLATER:
        case -NFS4ERR_RECALLCONFLICT:
                return -EREMOTEIO;
        case -NFS4ERR_WRONGSEC:
        case -NFS4ERR_WRONG_CRED:
                return -EPERM;
        case -NFS4ERR_BADOWNER:
        case -NFS4ERR_BADNAME:
                return -EINVAL;
        case -NFS4ERR_SHARE_DENIED:
                return -EACCES;
        case -NFS4ERR_MINOR_VERS_MISMATCH:
                return -EPROTONOSUPPORT;
        case -NFS4ERR_FILE_OPEN:
                return -EBUSY;
        default:
                dprintk("%s could not handle NFSv4 error %d\n",
                                __func__, -err);
                break;
        }
        return -EIO;
}

/*
 * This is our standard bitmap for GETATTR requests.
 */
const u32 nfs4_fattr_bitmap[3] = {
        FATTR4_WORD0_TYPE
        | FATTR4_WORD0_CHANGE
        | FATTR4_WORD0_SIZE
        | FATTR4_WORD0_FSID
        | FATTR4_WORD0_FILEID,
        FATTR4_WORD1_MODE
        | FATTR4_WORD1_NUMLINKS
        | FATTR4_WORD1_OWNER
        | FATTR4_WORD1_OWNER_GROUP
        | FATTR4_WORD1_RAWDEV
        | FATTR4_WORD1_SPACE_USED
        | FATTR4_WORD1_TIME_ACCESS
        | FATTR4_WORD1_TIME_METADATA
        | FATTR4_WORD1_TIME_MODIFY
        | FATTR4_WORD1_MOUNTED_ON_FILEID,
#ifdef CONFIG_NFS_V4_SECURITY_LABEL
        FATTR4_WORD2_SECURITY_LABEL
#endif
};

static const u32 nfs4_pnfs_open_bitmap[3] = {
        FATTR4_WORD0_TYPE
        | FATTR4_WORD0_CHANGE
        | FATTR4_WORD0_SIZE
        | FATTR4_WORD0_FSID
        | FATTR4_WORD0_FILEID,
        FATTR4_WORD1_MODE
        | FATTR4_WORD1_NUMLINKS
        | FATTR4_WORD1_OWNER
        | FATTR4_WORD1_OWNER_GROUP
        | FATTR4_WORD1_RAWDEV
        | FATTR4_WORD1_SPACE_USED
        | FATTR4_WORD1_TIME_ACCESS
        | FATTR4_WORD1_TIME_METADATA
        | FATTR4_WORD1_TIME_MODIFY,
        FATTR4_WORD2_MDSTHRESHOLD
#ifdef CONFIG_NFS_V4_SECURITY_LABEL
        | FATTR4_WORD2_SECURITY_LABEL
#endif
};

static const u32 nfs4_open_noattr_bitmap[3] = {
        FATTR4_WORD0_TYPE
        | FATTR4_WORD0_FILEID,
};

const u32 nfs4_statfs_bitmap[3] = {
        FATTR4_WORD0_FILES_AVAIL
        | FATTR4_WORD0_FILES_FREE
        | FATTR4_WORD0_FILES_TOTAL,
        FATTR4_WORD1_SPACE_AVAIL
        | FATTR4_WORD1_SPACE_FREE
        | FATTR4_WORD1_SPACE_TOTAL
};

const u32 nfs4_pathconf_bitmap[3] = {
        FATTR4_WORD0_MAXLINK
        | FATTR4_WORD0_MAXNAME,
        0
};

const u32 nfs4_fsinfo_bitmap[3] = { FATTR4_WORD0_MAXFILESIZE
                        | FATTR4_WORD0_MAXREAD
                        | FATTR4_WORD0_MAXWRITE
                        | FATTR4_WORD0_LEASE_TIME,
                        FATTR4_WORD1_TIME_DELTA
                        | FATTR4_WORD1_FS_LAYOUT_TYPES,
                        FATTR4_WORD2_LAYOUT_BLKSIZE
                        | FATTR4_WORD2_CLONE_BLKSIZE
};

const u32 nfs4_fs_locations_bitmap[3] = {
        FATTR4_WORD0_CHANGE
        | FATTR4_WORD0_SIZE
        | FATTR4_WORD0_FSID
        | FATTR4_WORD0_FILEID
        | FATTR4_WORD0_FS_LOCATIONS,
        FATTR4_WORD1_OWNER
        | FATTR4_WORD1_OWNER_GROUP
        | FATTR4_WORD1_RAWDEV
        | FATTR4_WORD1_SPACE_USED
        | FATTR4_WORD1_TIME_ACCESS
        | FATTR4_WORD1_TIME_METADATA
        | FATTR4_WORD1_TIME_MODIFY
        | FATTR4_WORD1_MOUNTED_ON_FILEID,
};

static void nfs4_setup_readdir(u64 cookie, __be32 *verifier, struct dentry *dentry,
                struct nfs4_readdir_arg *readdir)
{
        unsigned int attrs = FATTR4_WORD0_FILEID | FATTR4_WORD0_TYPE;
        __be32 *start, *p;

        if (cookie > 2) {
                readdir->cookie = cookie;
                memcpy(&readdir->verifier, verifier, sizeof(readdir->verifier));
                return;
        }

        readdir->cookie = 0;
        memset(&readdir->verifier, 0, sizeof(readdir->verifier));
        if (cookie == 2)
                return;
        
        /*
         * NFSv4 servers do not return entries for '.' and '..'
         * Therefore, we fake these entries here.  We let '.'
         * have cookie 0 and '..' have cookie 1.  Note that
         * when talking to the server, we always send cookie 0
         * instead of 1 or 2.
         */
        start = p = kmap_atomic(*readdir->pages);
        
        if (cookie == 0) {
                *p++ = xdr_one;                                  /* next */
                *p++ = xdr_zero;                   /* cookie, first word */
                *p++ = xdr_one;                   /* cookie, second word */
                *p++ = xdr_one;                             /* entry len */
                memcpy(p, ".\0\0\0", 4);                        /* entry */
                p++;
                *p++ = xdr_one;                         /* bitmap length */
                *p++ = htonl(attrs);                           /* bitmap */
                *p++ = htonl(12);             /* attribute buffer length */
                *p++ = htonl(NF4DIR);
                p = xdr_encode_hyper(p, NFS_FILEID(d_inode(dentry)));
        }
        
        *p++ = xdr_one;                                  /* next */
        *p++ = xdr_zero;                   /* cookie, first word */
        *p++ = xdr_two;                   /* cookie, second word */
        *p++ = xdr_two;                             /* entry len */
        memcpy(p, "..\0\0", 4);                         /* entry */
        p++;
        *p++ = xdr_one;                         /* bitmap length */
        *p++ = htonl(attrs);                           /* bitmap */
        *p++ = htonl(12);             /* attribute buffer length */
        *p++ = htonl(NF4DIR);
        p = xdr_encode_hyper(p, NFS_FILEID(d_inode(dentry->d_parent)));

        readdir->pgbase = (char *)p - (char *)start;
        readdir->count -= readdir->pgbase;
        kunmap_atomic(start);
}

static void nfs4_test_and_free_stateid(struct nfs_server *server,
                nfs4_stateid *stateid,
                struct rpc_cred *cred)
{
        const struct nfs4_minor_version_ops *ops = server->nfs_client->cl_mvops;

        ops->test_and_free_expired(server, stateid, cred);
}

static void __nfs4_free_revoked_stateid(struct nfs_server *server,
                nfs4_stateid *stateid,
                struct rpc_cred *cred)
{
        stateid->type = NFS4_REVOKED_STATEID_TYPE;
        nfs4_test_and_free_stateid(server, stateid, cred);
}

static void nfs4_free_revoked_stateid(struct nfs_server *server,
                const nfs4_stateid *stateid,
                struct rpc_cred *cred)
{
        nfs4_stateid tmp;

        nfs4_stateid_copy(&tmp, stateid);
        __nfs4_free_revoked_stateid(server, &tmp, cred);
}

static long nfs4_update_delay(long *timeout)
{
        long ret;
        if (!timeout)
                return NFS4_POLL_RETRY_MAX;
        if (*timeout <= 0)
                *timeout = NFS4_POLL_RETRY_MIN;
        if (*timeout > NFS4_POLL_RETRY_MAX)
                *timeout = NFS4_POLL_RETRY_MAX;
        ret = *timeout;
        *timeout <<= 1;
        return ret;
}

static int nfs4_delay(struct rpc_clnt *clnt, long *timeout)
{
        int res = 0;

        might_sleep();

        freezable_schedule_timeout_killable_unsafe(
                nfs4_update_delay(timeout));
        if (fatal_signal_pending(current))
                res = -ERESTARTSYS;
        return res;
}

/* This is the error handling routine for processes that are allowed
 * to sleep.
 */
static int nfs4_do_handle_exception(struct nfs_server *server,
                int errorcode, struct nfs4_exception *exception)
{
        struct nfs_client *clp = server->nfs_client;
        struct nfs4_state *state = exception->state;
        const nfs4_stateid *stateid = exception->stateid;
        struct inode *inode = exception->inode;
        int ret = errorcode;

        exception->delay = 0;
        exception->recovering = 0;
        exception->retry = 0;

        if (stateid == NULL && state != NULL)
                stateid = &state->stateid;

        switch(errorcode) {
                case 0:
                        return 0;
                case -NFS4ERR_DELEG_REVOKED:
                case -NFS4ERR_ADMIN_REVOKED:
                case -NFS4ERR_EXPIRED:
                case -NFS4ERR_BAD_STATEID:
                        if (inode != NULL && stateid != NULL) {
                                nfs_inode_find_state_and_recover(inode,
                                                stateid);
                                goto wait_on_recovery;
                        }
                case -NFS4ERR_OPENMODE:
                        if (inode) {
                                int err;

                                err = nfs_async_inode_return_delegation(inode,
                                                stateid);
                                if (err == 0)
                                        goto wait_on_recovery;
                                if (stateid != NULL && stateid->type == NFS4_DELEGATION_STATEID_TYPE) {
                                        exception->retry = 1;
                                        break;
                                }
                        }
                        if (state == NULL)
                                break;
                        ret = nfs4_schedule_stateid_recovery(server, state);
                        if (ret < 0)
                                break;
                        goto wait_on_recovery;
                case -NFS4ERR_STALE_STATEID:
                case -NFS4ERR_STALE_CLIENTID:
                        nfs4_schedule_lease_recovery(clp);
                        goto wait_on_recovery;
                case -NFS4ERR_MOVED:
                        ret = nfs4_schedule_migration_recovery(server);
                        if (ret < 0)
                                break;
                        goto wait_on_recovery;
                case -NFS4ERR_LEASE_MOVED:
                        nfs4_schedule_lease_moved_recovery(clp);
                        goto wait_on_recovery;
#if defined(CONFIG_NFS_V4_1)
                case -NFS4ERR_BADSESSION:
                case -NFS4ERR_BADSLOT:
                case -NFS4ERR_BAD_HIGH_SLOT:
                case -NFS4ERR_CONN_NOT_BOUND_TO_SESSION:
                case -NFS4ERR_DEADSESSION:
                case -NFS4ERR_SEQ_FALSE_RETRY:
                case -NFS4ERR_SEQ_MISORDERED:
                        dprintk("%s ERROR: %d Reset session\n", __func__,
                                errorcode);
                        nfs4_schedule_session_recovery(clp->cl_session, errorcode);
                        goto wait_on_recovery;
#endif /* defined(CONFIG_NFS_V4_1) */
                case -NFS4ERR_FILE_OPEN:
                        if (exception->timeout > HZ) {
                                /* We have retried a decent amount, time to
                                 * fail
                                 */
                                ret = -EBUSY;
                                break;
                        }
                case -NFS4ERR_DELAY:
                        nfs_inc_server_stats(server, NFSIOS_DELAY);
                case -NFS4ERR_GRACE:
                case -NFS4ERR_LAYOUTTRYLATER:
                case -NFS4ERR_RECALLCONFLICT:
                        exception->delay = 1;
                        return 0;

                case -NFS4ERR_RETRY_UNCACHED_REP:
                case -NFS4ERR_OLD_STATEID:
                        exception->retry = 1;
                        break;
                case -NFS4ERR_BADOWNER:
                        /* The following works around a Linux server bug! */
                case -NFS4ERR_BADNAME:
                        if (server->caps & NFS_CAP_UIDGID_NOMAP) {
                                server->caps &= ~NFS_CAP_UIDGID_NOMAP;
                                exception->retry = 1;
                                printk(KERN_WARNING "NFS: v4 server %s "
                                                "does not accept raw "
                                                "uid/gids. "
                                                "Reenabling the idmapper.\n",
                                                server->nfs_client->cl_hostname);
                        }
        }
        /* We failed to handle the error */
        return nfs4_map_errors(ret);
wait_on_recovery:
        exception->recovering = 1;
        return 0;
}

/* This is the error handling routine for processes that are allowed
 * to sleep.
 */
int nfs4_handle_exception(struct nfs_server *server, int errorcode, struct nfs4_exception *exception)
{
        struct nfs_client *clp = server->nfs_client;
        int ret;

        ret = nfs4_do_handle_exception(server, errorcode, exception);
        if (exception->delay) {
                ret = nfs4_delay(server->client, &exception->timeout);
                goto out_retry;
        }
        if (exception->recovering) {
                ret = nfs4_wait_clnt_recover(clp);
                if (test_bit(NFS_MIG_FAILED, &server->mig_status))
                        return -EIO;
                goto out_retry;
        }
        return ret;
out_retry:
        if (ret == 0)
                exception->retry = 1;
        return ret;
}

static int
nfs4_async_handle_exception(struct rpc_task *task, struct nfs_server *server,
                int errorcode, struct nfs4_exception *exception)
{
        struct nfs_client *clp = server->nfs_client;
        int ret;

        ret = nfs4_do_handle_exception(server, errorcode, exception);
        if (exception->delay) {
                rpc_delay(task, nfs4_update_delay(&exception->timeout));
                goto out_retry;
        }
        if (exception->recovering) {
                rpc_sleep_on(&clp->cl_rpcwaitq, task, NULL);
                if (test_bit(NFS4CLNT_MANAGER_RUNNING, &clp->cl_state) == 0)
                        rpc_wake_up_queued_task(&clp->cl_rpcwaitq, task);
                goto out_retry;
        }
        if (test_bit(NFS_MIG_FAILED, &server->mig_status))
                ret = -EIO;
        return ret;
out_retry:
        if (ret == 0) {
                exception->retry = 1;
                /*
                 * For NFS4ERR_MOVED, the client transport will need to
                 * be recomputed after migration recovery has completed.
                 */
                if (errorcode == -NFS4ERR_MOVED)
                        rpc_task_release_transport(task);
        }
        return ret;
}

static int
nfs4_async_handle_error(struct rpc_task *task, struct nfs_server *server,
                        struct nfs4_state *state, long *timeout)
{
        struct nfs4_exception exception = {
                .state = state,
        };

        if (task->tk_status >= 0)
                return 0;
        if (timeout)
                exception.timeout = *timeout;
        task->tk_status = nfs4_async_handle_exception(task, server,
                        task->tk_status,
                        &exception);
        if (exception.delay && timeout)
                *timeout = exception.timeout;
        if (exception.retry)
                return -EAGAIN;
        return 0;
}

/*
 * Return 'true' if 'clp' is using an rpc_client that is integrity protected
 * or 'false' otherwise.
 */
static bool _nfs4_is_integrity_protected(struct nfs_client *clp)
{
        rpc_authflavor_t flavor = clp->cl_rpcclient->cl_auth->au_flavor;
        return (flavor == RPC_AUTH_GSS_KRB5I) || (flavor == RPC_AUTH_GSS_KRB5P);
}

static void do_renew_lease(struct nfs_client *clp, unsigned long timestamp)
{
        spin_lock(&clp->cl_lock);
        if (time_before(clp->cl_last_renewal,timestamp))
                clp->cl_last_renewal = timestamp;
        spin_unlock(&clp->cl_lock);
}

static void renew_lease(const struct nfs_server *server, unsigned long timestamp)
{
        struct nfs_client *clp = server->nfs_client;

        if (!nfs4_has_session(clp))
                do_renew_lease(clp, timestamp);
}

struct nfs4_call_sync_data {
        const struct nfs_server *seq_server;
        struct nfs4_sequence_args *seq_args;
        struct nfs4_sequence_res *seq_res;
};

void nfs4_init_sequence(struct nfs4_sequence_args *args,
                        struct nfs4_sequence_res *res, int cache_reply)
{
        args->sa_slot = NULL;
        args->sa_cache_this = cache_reply;
        args->sa_privileged = 0;

        res->sr_slot = NULL;
}

static void nfs4_set_sequence_privileged(struct nfs4_sequence_args *args)
{
        args->sa_privileged = 1;
}

static void nfs40_sequence_free_slot(struct nfs4_sequence_res *res)
{
        struct nfs4_slot *slot = res->sr_slot;
        struct nfs4_slot_table *tbl;

        tbl = slot->table;
        spin_lock(&tbl->slot_tbl_lock);
        if (!nfs41_wake_and_assign_slot(tbl, slot))
                nfs4_free_slot(tbl, slot);
        spin_unlock(&tbl->slot_tbl_lock);

        res->sr_slot = NULL;
}

static int nfs40_sequence_done(struct rpc_task *task,
                               struct nfs4_sequence_res *res)
{
        if (res->sr_slot != NULL)
                nfs40_sequence_free_slot(res);
        return 1;
}

#if defined(CONFIG_NFS_V4_1)

static void nfs41_release_slot(struct nfs4_slot *slot)
{
        struct nfs4_session *session;
        struct nfs4_slot_table *tbl;
        bool send_new_highest_used_slotid = false;

        if (!slot)
                return;
        tbl = slot->table;
        session = tbl->session;

        /* Bump the slot sequence number */
        if (slot->seq_done)
                slot->seq_nr++;
        slot->seq_done = 0;

        spin_lock(&tbl->slot_tbl_lock);
        /* Be nice to the server: try to ensure that the last transmitted
         * value for highest_user_slotid <= target_highest_slotid
         */
        if (tbl->highest_used_slotid > tbl->target_highest_slotid)
                send_new_highest_used_slotid = true;

        if (nfs41_wake_and_assign_slot(tbl, slot)) {
                send_new_highest_used_slotid = false;
                goto out_unlock;
        }
        nfs4_free_slot(tbl, slot);

        if (tbl->highest_used_slotid != NFS4_NO_SLOT)
                send_new_highest_used_slotid = false;
out_unlock:
        spin_unlock(&tbl->slot_tbl_lock);
        if (send_new_highest_used_slotid)
                nfs41_notify_server(session->clp);
        if (waitqueue_active(&tbl->slot_waitq))
                wake_up_all(&tbl->slot_waitq);
}

static void nfs41_sequence_free_slot(struct nfs4_sequence_res *res)
{
        nfs41_release_slot(res->sr_slot);
        res->sr_slot = NULL;
}

static int nfs41_sequence_process(struct rpc_task *task,
                struct nfs4_sequence_res *res)
{
        struct nfs4_session *session;
        struct nfs4_slot *slot = res->sr_slot;
        struct nfs_client *clp;
        bool interrupted = false;
        int ret = 1;

        if (slot == NULL)
                goto out_noaction;
        /* don't increment the sequence number if the task wasn't sent */
        if (!RPC_WAS_SENT(task))
                goto out;

        session = slot->table->session;

        if (slot->interrupted) {
                if (res->sr_status != -NFS4ERR_DELAY)
                        slot->interrupted = 0;
                interrupted = true;
        }

        trace_nfs4_sequence_done(session, res);
        /* Check the SEQUENCE operation status */
        switch (res->sr_status) {
        case 0:
                /* Update the slot's sequence and clientid lease timer */
                slot->seq_done = 1;
                clp = session->clp;
                do_renew_lease(clp, res->sr_timestamp);
                /* Check sequence flags */
                nfs41_handle_sequence_flag_errors(clp, res->sr_status_flags,
                                !!slot->privileged);
                nfs41_update_target_slotid(slot->table, slot, res);
                break;
        case 1:
                /*
                 * sr_status remains 1 if an RPC level error occurred.
                 * The server may or may not have processed the sequence
                 * operation..
                 * Mark the slot as having hosted an interrupted RPC call.
                 */
                slot->interrupted = 1;
                goto out;
        case -NFS4ERR_DELAY:
                /* The server detected a resend of the RPC call and
                 * returned NFS4ERR_DELAY as per Section 2.10.6.2
                 * of RFC5661.
                 */
                dprintk("%s: slot=%u seq=%u: Operation in progress\n",
                        __func__,
                        slot->slot_nr,
                        slot->seq_nr);
                goto out_retry;
        case -NFS4ERR_RETRY_UNCACHED_REP:
        case -NFS4ERR_SEQ_FALSE_RETRY:
                /*
                 * The server thinks we tried to replay a request.
                 * Retry the call after bumping the sequence ID.
                 */
                goto retry_new_seq;
        case -NFS4ERR_BADSLOT:
                /*
                 * The slot id we used was probably retired. Try again
                 * using a different slot id.
                 */
                if (slot->slot_nr < slot->table->target_highest_slotid)
                        goto session_recover;
                goto retry_nowait;
        case -NFS4ERR_SEQ_MISORDERED:
                /*
                 * Was the last operation on this sequence interrupted?
                 * If so, retry after bumping the sequence number.
                 */
                if (interrupted)
                        goto retry_new_seq;
                /*
                 * Could this slot have been previously retired?
                 * If so, then the server may be expecting seq_nr = 1!
                 */
                if (slot->seq_nr != 1) {
                        slot->seq_nr = 1;
                        goto retry_nowait;
                }
                goto session_recover;
        default:
                /* Just update the slot sequence no. */
                slot->seq_done = 1;
        }
out:
        /* The session may be reset by one of the error handlers. */
        dprintk("%s: Error %d free the slot \n", __func__, res->sr_status);
out_noaction:
        return ret;
session_recover:
        nfs4_schedule_session_recovery(session, res->sr_status);
        goto retry_nowait;
retry_new_seq:
        ++slot->seq_nr;
retry_nowait:
        if (rpc_restart_call_prepare(task)) {
                nfs41_sequence_free_slot(res);
                task->tk_status = 0;
                ret = 0;
        }
        goto out;
out_retry:
        if (!rpc_restart_call(task))
                goto out;
        rpc_delay(task, NFS4_POLL_RETRY_MAX);
        return 0;
}

int nfs41_sequence_done(struct rpc_task *task, struct nfs4_sequence_res *res)
{
        if (!nfs41_sequence_process(task, res))
                return 0;
        if (res->sr_slot != NULL)
                nfs41_sequence_free_slot(res);
        return 1;

}
EXPORT_SYMBOL_GPL(nfs41_sequence_done);

static int nfs4_sequence_process(struct rpc_task *task, struct nfs4_sequence_res *res)
{
        if (res->sr_slot == NULL)
                return 1;
        if (res->sr_slot->table->session != NULL)
                return nfs41_sequence_process(task, res);
        return nfs40_sequence_done(task, res);
}

static void nfs4_sequence_free_slot(struct nfs4_sequence_res *res)
{
        if (res->sr_slot != NULL) {
                if (res->sr_slot->table->session != NULL)
                        nfs41_sequence_free_slot(res);
                else
                        nfs40_sequence_free_slot(res);
        }
}

int nfs4_sequence_done(struct rpc_task *task, struct nfs4_sequence_res *res)
{
        if (res->sr_slot == NULL)
                return 1;
        if (!res->sr_slot->table->session)
                return nfs40_sequence_done(task, res);
        return nfs41_sequence_done(task, res);
}
EXPORT_SYMBOL_GPL(nfs4_sequence_done);

static void nfs41_call_sync_prepare(struct rpc_task *task, void *calldata)
{
        struct nfs4_call_sync_data *data = calldata;

        dprintk("--> %s data->seq_server %p\n", __func__, data->seq_server);

        nfs4_setup_sequence(data->seq_server->nfs_client,
                            data->seq_args, data->seq_res, task);
}

static void nfs41_call_sync_done(struct rpc_task *task, void *calldata)
{
        struct nfs4_call_sync_data *data = calldata;

        nfs41_sequence_done(task, data->seq_res);
}

static const struct rpc_call_ops nfs41_call_sync_ops = {
        .rpc_call_prepare = nfs41_call_sync_prepare,
        .rpc_call_done = nfs41_call_sync_done,
};

static void
nfs4_sequence_process_interrupted(struct nfs_client *client,
                struct nfs4_slot *slot, struct rpc_cred *cred)
{
        struct rpc_task *task;

        task = _nfs41_proc_sequence(client, cred, slot, true);
        if (!IS_ERR(task))
                rpc_put_task_async(task);
}

#else   /* !CONFIG_NFS_V4_1 */

static int nfs4_sequence_process(struct rpc_task *task, struct nfs4_sequence_res *res)
{
        return nfs40_sequence_done(task, res);
}

static void nfs4_sequence_free_slot(struct nfs4_sequence_res *res)
{
        if (res->sr_slot != NULL)
                nfs40_sequence_free_slot(res);
}

int nfs4_sequence_done(struct rpc_task *task,
                       struct nfs4_sequence_res *res)
{
        return nfs40_sequence_done(task, res);
}
EXPORT_SYMBOL_GPL(nfs4_sequence_done);

static void
nfs4_sequence_process_interrupted(struct nfs_client *client,
                struct nfs4_slot *slot, struct rpc_cred *cred)
{
        WARN_ON_ONCE(1);
        slot->interrupted = 0;
}

#endif  /* !CONFIG_NFS_V4_1 */

static void nfs41_sequence_res_init(struct nfs4_sequence_res *res)
{
        res->sr_timestamp = jiffies;
        res->sr_status_flags = 0;
        res->sr_status = 1;
}

static
void nfs4_sequence_attach_slot(struct nfs4_sequence_args *args,
                struct nfs4_sequence_res *res,
                struct nfs4_slot *slot)
{
        if (!slot)
                return;
        slot->privileged = args->sa_privileged ? 1 : 0;
        args->sa_slot = slot;

        res->sr_slot = slot;
}

int nfs4_setup_sequence(struct nfs_client *client,
                        struct nfs4_sequence_args *args,
                        struct nfs4_sequence_res *res,
                        struct rpc_task *task)
{
        struct nfs4_session *session = nfs4_get_session(client);
        struct nfs4_slot_table *tbl  = client->cl_slot_tbl;
        struct nfs4_slot *slot;

        /* slot already allocated? */
        if (res->sr_slot != NULL)
                goto out_start;

        if (session) {
                tbl = &session->fc_slot_table;
                task->tk_timeout = 0;
        }

        for (;;) {
                spin_lock(&tbl->slot_tbl_lock);
                /* The state manager will wait until the slot table is empty */
                if (nfs4_slot_tbl_draining(tbl) && !args->sa_privileged)
                        goto out_sleep;

                slot = nfs4_alloc_slot(tbl);
                if (IS_ERR(slot)) {
                        /* Try again in 1/4 second */
                        if (slot == ERR_PTR(-ENOMEM))
                                task->tk_timeout = HZ >> 2;
                        goto out_sleep;
                }
                spin_unlock(&tbl->slot_tbl_lock);

                if (likely(!slot->interrupted))
                        break;
                nfs4_sequence_process_interrupted(client,
                                slot, task->tk_msg.rpc_cred);
        }

        nfs4_sequence_attach_slot(args, res, slot);

        trace_nfs4_setup_sequence(session, args);
out_start:
        nfs41_sequence_res_init(res);
        rpc_call_start(task);
        return 0;

out_sleep:
        if (args->sa_privileged)
                rpc_sleep_on_priority(&tbl->slot_tbl_waitq, task,
                                NULL, RPC_PRIORITY_PRIVILEGED);
        else
                rpc_sleep_on(&tbl->slot_tbl_waitq, task, NULL);
        spin_unlock(&tbl->slot_tbl_lock);
        return -EAGAIN;
}
EXPORT_SYMBOL_GPL(nfs4_setup_sequence);

static void nfs40_call_sync_prepare(struct rpc_task *task, void *calldata)
{
        struct nfs4_call_sync_data *data = calldata;
        nfs4_setup_sequence(data->seq_server->nfs_client,
                                data->seq_args, data->seq_res, task);
}

static void nfs40_call_sync_done(struct rpc_task *task, void *calldata)
{
        struct nfs4_call_sync_data *data = calldata;
        nfs4_sequence_done(task, data->seq_res);
}

static const struct rpc_call_ops nfs40_call_sync_ops = {
        .rpc_call_prepare = nfs40_call_sync_prepare,
        .rpc_call_done = nfs40_call_sync_done,
};

static int nfs4_call_sync_sequence(struct rpc_clnt *clnt,
                                   struct nfs_server *server,
                                   struct rpc_message *msg,
                                   struct nfs4_sequence_args *args,
                                   struct nfs4_sequence_res *res)
{
        int ret;
        struct rpc_task *task;
        struct nfs_client *clp = server->nfs_client;
        struct nfs4_call_sync_data data = {
                .seq_server = server,
                .seq_args = args,
                .seq_res = res,
        };
        struct rpc_task_setup task_setup = {
                .rpc_client = clnt,
                .rpc_message = msg,
                .callback_ops = clp->cl_mvops->call_sync_ops,
                .callback_data = &data
        };

        task = rpc_run_task(&task_setup);
        if (IS_ERR(task))
                ret = PTR_ERR(task);
        else {
                ret = task->tk_status;
                rpc_put_task(task);
        }
        return ret;
}

int nfs4_call_sync(struct rpc_clnt *clnt,
                   struct nfs_server *server,
                   struct rpc_message *msg,
                   struct nfs4_sequence_args *args,
                   struct nfs4_sequence_res *res,
                   int cache_reply)
{
        nfs4_init_sequence(args, res, cache_reply);
        return nfs4_call_sync_sequence(clnt, server, msg, args, res);
}

static void update_changeattr(struct inode *dir, struct nfs4_change_info *cinfo,
                unsigned long timestamp)
{
        struct nfs_inode *nfsi = NFS_I(dir);

        spin_lock(&dir->i_lock);
        nfsi->cache_validity |= NFS_INO_INVALID_ATTR|NFS_INO_INVALID_DATA;
        if (cinfo->atomic && cinfo->before == dir->i_version) {
                nfsi->cache_validity &= ~NFS_INO_REVAL_PAGECACHE;
                nfsi->attrtimeo_timestamp = jiffies;
        } else {
                nfs_force_lookup_revalidate(dir);
                if (cinfo->before != dir->i_version)
                        nfsi->cache_validity |= NFS_INO_INVALID_ACCESS |
                                NFS_INO_INVALID_ACL;
        }
        dir->i_version = cinfo->after;
        nfsi->read_cache_jiffies = timestamp;
        nfsi->attr_gencount = nfs_inc_attr_generation_counter();
        nfs_fscache_invalidate(dir);
        spin_unlock(&dir->i_lock);
}

struct nfs4_opendata {
        struct kref kref;
        struct nfs_openargs o_arg;
        struct nfs_openres o_res;
        struct nfs_open_confirmargs c_arg;
        struct nfs_open_confirmres c_res;
        struct nfs4_string owner_name;
        struct nfs4_string group_name;
        struct nfs4_label *a_label;
        struct nfs_fattr f_attr;
        struct nfs4_label *f_label;
        struct dentry *dir;
        struct dentry *dentry;
        struct nfs4_state_owner *owner;
        struct nfs4_state *state;
        struct iattr attrs;
        unsigned long timestamp;
        bool rpc_done;
        bool file_created;
        bool is_recover;
        bool cancelled;
        int rpc_status;
};

struct nfs4_open_createattrs {
        struct nfs4_label *label;
        struct iattr *sattr;
        const __u32 verf[2];
};

static bool nfs4_clear_cap_atomic_open_v1(struct nfs_server *server,
                int err, struct nfs4_exception *exception)
{
        if (err != -EINVAL)
                return false;
        if (!(server->caps & NFS_CAP_ATOMIC_OPEN_V1))
                return false;
        server->caps &= ~NFS_CAP_ATOMIC_OPEN_V1;
        exception->retry = 1;
        return true;
}

static u32
nfs4_map_atomic_open_share(struct nfs_server *server,
                fmode_t fmode, int openflags)
{
        u32 res = 0;

        switch (fmode & (FMODE_READ | FMODE_WRITE)) {
        case FMODE_READ:
                res = NFS4_SHARE_ACCESS_READ;
                break;
        case FMODE_WRITE:
                res = NFS4_SHARE_ACCESS_WRITE;
                break;
        case FMODE_READ|FMODE_WRITE:
                res = NFS4_SHARE_ACCESS_BOTH;
        }
        if (!(server->caps & NFS_CAP_ATOMIC_OPEN_V1))
                goto out;
        /* Want no delegation if we're using O_DIRECT */
        if (openflags & O_DIRECT)
                res |= NFS4_SHARE_WANT_NO_DELEG;
out:
        return res;
}

static enum open_claim_type4
nfs4_map_atomic_open_claim(struct nfs_server *server,
                enum open_claim_type4 claim)
{
        if (server->caps & NFS_CAP_ATOMIC_OPEN_V1)
                return claim;
        switch (claim) {
        default:
                return claim;
        case NFS4_OPEN_CLAIM_FH:
                return NFS4_OPEN_CLAIM_NULL;
        case NFS4_OPEN_CLAIM_DELEG_CUR_FH:
                return NFS4_OPEN_CLAIM_DELEGATE_CUR;
        case NFS4_OPEN_CLAIM_DELEG_PREV_FH:
                return NFS4_OPEN_CLAIM_DELEGATE_PREV;
        }
}

static void nfs4_init_opendata_res(struct nfs4_opendata *p)
{
        p->o_res.f_attr = &p->f_attr;
        p->o_res.f_label = p->f_label;
        p->o_res.seqid = p->o_arg.seqid;
        p->c_res.seqid = p->c_arg.seqid;
        p->o_res.server = p->o_arg.server;
        p->o_res.access_request = p->o_arg.access;
        nfs_fattr_init(&p->f_attr);
        nfs_fattr_init_names(&p->f_attr, &p->owner_name, &p->group_name);
}

static struct nfs4_opendata *nfs4_opendata_alloc(struct dentry *dentry,
                struct nfs4_state_owner *sp, fmode_t fmode, int flags,
                const struct nfs4_open_createattrs *c,
                enum open_claim_type4 claim,
                gfp_t gfp_mask)
{
        struct dentry *parent = dget_parent(dentry);
        struct inode *dir = d_inode(parent);
        struct nfs_server *server = NFS_SERVER(dir);
        struct nfs_seqid *(*alloc_seqid)(struct nfs_seqid_counter *, gfp_t);
        struct nfs4_label *label = (c != NULL) ? c->label : NULL;
        struct nfs4_opendata *p;

        p = kzalloc(sizeof(*p), gfp_mask);
        if (p == NULL)
                goto err;

        p->f_label = nfs4_label_alloc(server, gfp_mask);
        if (IS_ERR(p->f_label))
                goto err_free_p;

        p->a_label = nfs4_label_alloc(server, gfp_mask);
        if (IS_ERR(p->a_label))
                goto err_free_f;

        alloc_seqid = server->nfs_client->cl_mvops->alloc_seqid;
        p->o_arg.seqid = alloc_seqid(&sp->so_seqid, gfp_mask);
        if (IS_ERR(p->o_arg.seqid))
                goto err_free_label;
        nfs_sb_active(dentry->d_sb);
        p->dentry = dget(dentry);
        p->dir = parent;
        p->owner = sp;
        atomic_inc(&sp->so_count);
        p->o_arg.open_flags = flags;
        p->o_arg.fmode = fmode & (FMODE_READ|FMODE_WRITE);
        p->o_arg.umask = current_umask();
        p->o_arg.claim = nfs4_map_atomic_open_claim(server, claim);
        p->o_arg.share_access = nfs4_map_atomic_open_share(server,
                        fmode, flags);
        /* don't put an ACCESS op in OPEN compound if O_EXCL, because ACCESS
         * will return permission denied for all bits until close */
        if (!(flags & O_EXCL)) {
                /* ask server to check for all possible rights as results
                 * are cached */
                switch (p->o_arg.claim) {
                default:
                        break;
                case NFS4_OPEN_CLAIM_NULL:
                case NFS4_OPEN_CLAIM_FH:
                        p->o_arg.access = NFS4_ACCESS_READ |
                                NFS4_ACCESS_MODIFY |
                                NFS4_ACCESS_EXTEND |
                                NFS4_ACCESS_EXECUTE;
                }
        }
        p->o_arg.clientid = server->nfs_client->cl_clientid;
        p->o_arg.id.create_time = ktime_to_ns(sp->so_seqid.create_time);
        p->o_arg.id.uniquifier = sp->so_seqid.owner_id;
        p->o_arg.name = &dentry->d_name;
        p->o_arg.server = server;
        p->o_arg.bitmask = nfs4_bitmask(server, label);
        p->o_arg.open_bitmap = &nfs4_fattr_bitmap[0];
        p->o_arg.label = nfs4_label_copy(p->a_label, label);
        switch (p->o_arg.claim) {
        case NFS4_OPEN_CLAIM_NULL:
        case NFS4_OPEN_CLAIM_DELEGATE_CUR:
        case NFS4_OPEN_CLAIM_DELEGATE_PREV:
                p->o_arg.fh = NFS_FH(dir);
                break;
        case NFS4_OPEN_CLAIM_PREVIOUS:
        case NFS4_OPEN_CLAIM_FH:
        case NFS4_OPEN_CLAIM_DELEG_CUR_FH:
        case NFS4_OPEN_CLAIM_DELEG_PREV_FH:
                p->o_arg.fh = NFS_FH(d_inode(dentry));
        }
        if (c != NULL && c->sattr != NULL && c->sattr->ia_valid != 0) {
                p->o_arg.u.attrs = &p->attrs;
                memcpy(&p->attrs, c->sattr, sizeof(p->attrs));

                memcpy(p->o_arg.u.verifier.data, c->verf,
                                sizeof(p->o_arg.u.verifier.data));
        }
        p->c_arg.fh = &p->o_res.fh;
        p->c_arg.stateid = &p->o_res.stateid;
        p->c_arg.seqid = p->o_arg.seqid;
        nfs4_init_opendata_res(p);
        kref_init(&p->kref);
        return p;

err_free_label:
        nfs4_label_free(p->a_label);
err_free_f:
        nfs4_label_free(p->f_label);
err_free_p:
        kfree(p);
err:
        dput(parent);
        return NULL;
}

static void nfs4_opendata_free(struct kref *kref)
{
        struct nfs4_opendata *p = container_of(kref,
                        struct nfs4_opendata, kref);
        struct super_block *sb = p->dentry->d_sb;

        nfs_free_seqid(p->o_arg.seqid);
        nfs4_sequence_free_slot(&p->o_res.seq_res);
        if (p->state != NULL)
                nfs4_put_open_state(p->state);
        nfs4_put_state_owner(p->owner);

        nfs4_label_free(p->a_label);
        nfs4_label_free(p->f_label);

        dput(p->dir);
        dput(p->dentry);
        nfs_sb_deactive(sb);
        nfs_fattr_free_names(&p->f_attr);
        kfree(p->f_attr.mdsthreshold);
        kfree(p);
}

static void nfs4_opendata_put(struct nfs4_opendata *p)
{
        if (p != NULL)
                kref_put(&p->kref, nfs4_opendata_free);
}

static bool nfs4_mode_match_open_stateid(struct nfs4_state *state,
                fmode_t fmode)
{
        switch(fmode & (FMODE_READ|FMODE_WRITE)) {
        case FMODE_READ|FMODE_WRITE:
                return state->n_rdwr != 0;
        case FMODE_WRITE:
                return state->n_wronly != 0;
        case FMODE_READ:
                return state->n_rdonly != 0;
        }
        WARN_ON_ONCE(1);
        return false;
}

static int can_open_cached(struct nfs4_state *state, fmode_t mode,
                int open_mode, enum open_claim_type4 claim)
{
        int ret = 0;

        if (open_mode & (O_EXCL|O_TRUNC))
                goto out;
        switch (claim) {
        case NFS4_OPEN_CLAIM_NULL:
        case NFS4_OPEN_CLAIM_FH:
                goto out;
        default:
                break;
        }
        switch (mode & (FMODE_READ|FMODE_WRITE)) {
                case FMODE_READ:
                        ret |= test_bit(NFS_O_RDONLY_STATE, &state->flags) != 0
                                && state->n_rdonly != 0;
                        break;
                case FMODE_WRITE:
                        ret |= test_bit(NFS_O_WRONLY_STATE, &state->flags) != 0
                                && state->n_wronly != 0;
                        break;
                case FMODE_READ|FMODE_WRITE:
                        ret |= test_bit(NFS_O_RDWR_STATE, &state->flags) != 0
                                && state->n_rdwr != 0;
        }
out:
        return ret;
}

static int can_open_delegated(struct nfs_delegation *delegation, fmode_t fmode,
                enum open_claim_type4 claim)
{
        if (delegation == NULL)
                return 0;
        if ((delegation->type & fmode) != fmode)
                return 0;
        switch (claim) {
        case NFS4_OPEN_CLAIM_NULL:
        case NFS4_OPEN_CLAIM_FH:
                break;
        case NFS4_OPEN_CLAIM_PREVIOUS:
                if (!test_bit(NFS_DELEGATION_NEED_RECLAIM, &delegation->flags))
                        break;
        default:
                return 0;
        }
        nfs_mark_delegation_referenced(delegation);
        return 1;
}

static void update_open_stateflags(struct nfs4_state *state, fmode_t fmode)
{
        switch (fmode) {
                case FMODE_WRITE:
                        state->n_wronly++;
                        break;
                case FMODE_READ:
                        state->n_rdonly++;
                        break;
                case FMODE_READ|FMODE_WRITE:
                        state->n_rdwr++;
        }
        nfs4_state_set_mode_locked(state, state->state | fmode);
}

#ifdef CONFIG_NFS_V4_1
static bool nfs_open_stateid_recover_openmode(struct nfs4_state *state)
{
        if (state->n_rdonly && !test_bit(NFS_O_RDONLY_STATE, &state->flags))
                return true;
        if (state->n_wronly && !test_bit(NFS_O_WRONLY_STATE, &state->flags))
                return true;
        if (state->n_rdwr && !test_bit(NFS_O_RDWR_STATE, &state->flags))
                return true;
        return false;
}
#endif /* CONFIG_NFS_V4_1 */

static void nfs_test_and_clear_all_open_stateid(struct nfs4_state *state)
{
        struct nfs_client *clp = state->owner->so_server->nfs_client;
        bool need_recover = false;

        if (test_and_clear_bit(NFS_O_RDONLY_STATE, &state->flags) && state->n_rdonly)
                need_recover = true;
        if (test_and_clear_bit(NFS_O_WRONLY_STATE, &state->flags) && state->n_wronly)
                need_recover = true;
        if (test_and_clear_bit(NFS_O_RDWR_STATE, &state->flags) && state->n_rdwr)
                need_recover = true;
        if (need_recover)
                nfs4_state_mark_reclaim_nograce(clp, state);
}

static bool nfs_need_update_open_stateid(struct nfs4_state *state,
                const nfs4_stateid *stateid, nfs4_stateid *freeme)
{
        if (test_and_set_bit(NFS_OPEN_STATE, &state->flags) == 0)
                return true;
        if (!nfs4_stateid_match_other(stateid, &state->open_stateid)) {
                nfs4_stateid_copy(freeme, &state->open_stateid);
                nfs_test_and_clear_all_open_stateid(state);
                return true;
        }
        if (nfs4_stateid_is_newer(stateid, &state->open_stateid))
                return true;
        return false;
}

static void nfs_resync_open_stateid_locked(struct nfs4_state *state)
{
        if (!(state->n_wronly || state->n_rdonly || state->n_rdwr))
                return;
        if (state->n_wronly)
                set_bit(NFS_O_WRONLY_STATE, &state->flags);
        if (state->n_rdonly)
                set_bit(NFS_O_RDONLY_STATE, &state->flags);
        if (state->n_rdwr)
                set_bit(NFS_O_RDWR_STATE, &state->flags);
        set_bit(NFS_OPEN_STATE, &state->flags);
}

static void nfs_clear_open_stateid_locked(struct nfs4_state *state,
                nfs4_stateid *stateid, fmode_t fmode)
{
        clear_bit(NFS_O_RDWR_STATE, &state->flags);
        switch (fmode & (FMODE_READ|FMODE_WRITE)) {
        case FMODE_WRITE:
                clear_bit(NFS_O_RDONLY_STATE, &state->flags);
                break;
        case FMODE_READ:
                clear_bit(NFS_O_WRONLY_STATE, &state->flags);
                break;
        case 0:
                clear_bit(NFS_O_RDONLY_STATE, &state->flags);
                clear_bit(NFS_O_WRONLY_STATE, &state->flags);
                clear_bit(NFS_OPEN_STATE, &state->flags);
        }
        if (stateid == NULL)
                return;
        /* Handle OPEN+OPEN_DOWNGRADE races */
        if (nfs4_stateid_match_other(stateid, &state->open_stateid) &&
            !nfs4_stateid_is_newer(stateid, &state->open_stateid)) {
                nfs_resync_open_stateid_locked(state);
                return;
        }
        if (test_bit(NFS_DELEGATED_STATE, &state->flags) == 0)
                nfs4_stateid_copy(&state->stateid, stateid);
        nfs4_stateid_copy(&state->open_stateid, stateid);
}

static void nfs_clear_open_stateid(struct nfs4_state *state,
        nfs4_stateid *arg_stateid,
        nfs4_stateid *stateid, fmode_t fmode)
{
        write_seqlock(&state->seqlock);
        /* Ignore, if the CLOSE argment doesn't match the current stateid */
        if (nfs4_state_match_open_stateid_other(state, arg_stateid))
                nfs_clear_open_stateid_locked(state, stateid, fmode);
        write_sequnlock(&state->seqlock);
        if (test_bit(NFS_STATE_RECLAIM_NOGRACE, &state->flags))
                nfs4_schedule_state_manager(state->owner->so_server->nfs_client);
}

static void nfs_set_open_stateid_locked(struct nfs4_state *state,
                const nfs4_stateid *stateid, fmode_t fmode,
                nfs4_stateid *freeme)
{
        switch (fmode) {
                case FMODE_READ:
                        set_bit(NFS_O_RDONLY_STATE, &state->flags);
                        break;
                case FMODE_WRITE:
                        set_bit(NFS_O_WRONLY_STATE, &state->flags);
                        break;
                case FMODE_READ|FMODE_WRITE:
                        set_bit(NFS_O_RDWR_STATE, &state->flags);
        }
        if (!nfs_need_update_open_stateid(state, stateid, freeme))
                return;
        if (test_bit(NFS_DELEGATED_STATE, &state->flags) == 0)
                nfs4_stateid_copy(&state->stateid, stateid);
        nfs4_stateid_copy(&state->open_stateid, stateid);
}

static void __update_open_stateid(struct nfs4_state *state,
                const nfs4_stateid *open_stateid,
                const nfs4_stateid *deleg_stateid,
                fmode_t fmode,
                nfs4_stateid *freeme)
{
        /*
         * Protect the call to nfs4_state_set_mode_locked and
         * serialise the stateid update
         */
        spin_lock(&state->owner->so_lock);
        write_seqlock(&state->seqlock);
        if (deleg_stateid != NULL) {
                nfs4_stateid_copy(&state->stateid, deleg_stateid);
                set_bit(NFS_DELEGATED_STATE, &state->flags);
        }
        if (open_stateid != NULL)
                nfs_set_open_stateid_locked(state, open_stateid, fmode, freeme);
        write_sequnlock(&state->seqlock);
        update_open_stateflags(state, fmode);
        spin_unlock(&state->owner->so_lock);
}

static int update_open_stateid(struct nfs4_state *state,
                const nfs4_stateid *open_stateid,
                const nfs4_stateid *delegation,
                fmode_t fmode)
{
        struct nfs_server *server = NFS_SERVER(state->inode);
        struct nfs_client *clp = server->nfs_client;
        struct nfs_inode *nfsi = NFS_I(state->inode);
        struct nfs_delegation *deleg_cur;
        nfs4_stateid freeme = { };
        int ret = 0;

        fmode &= (FMODE_READ|FMODE_WRITE);

        rcu_read_lock();
        deleg_cur = rcu_dereference(nfsi->delegation);
        if (deleg_cur == NULL)
                goto no_delegation;

        spin_lock(&deleg_cur->lock);
        if (rcu_dereference(nfsi->delegation) != deleg_cur ||
           test_bit(NFS_DELEGATION_RETURNING, &deleg_cur->flags) ||
            (deleg_cur->type & fmode) != fmode)
                goto no_delegation_unlock;

        if (delegation == NULL)
                delegation = &deleg_cur->stateid;
        else if (!nfs4_stateid_match(&deleg_cur->stateid, delegation))
                goto no_delegation_unlock;

        nfs_mark_delegation_referenced(deleg_cur);
        __update_open_stateid(state, open_stateid, &deleg_cur->stateid,
                        fmode, &freeme);
        ret = 1;
no_delegation_unlock:
        spin_unlock(&deleg_cur->lock);
no_delegation:
        rcu_read_unlock();

        if (!ret && open_stateid != NULL) {
                __update_open_stateid(state, open_stateid, NULL, fmode, &freeme);
                ret = 1;
        }
        if (test_bit(NFS_STATE_RECLAIM_NOGRACE, &state->flags))
                nfs4_schedule_state_manager(clp);
        if (freeme.type != 0)
                nfs4_test_and_free_stateid(server, &freeme,
                                state->owner->so_cred);

        return ret;
}

static bool nfs4_update_lock_stateid(struct nfs4_lock_state *lsp,
                const nfs4_stateid *stateid)
{
        struct nfs4_state *state = lsp->ls_state;
        bool ret = false;

        spin_lock(&state->state_lock);
        if (!nfs4_stateid_match_other(stateid, &lsp->ls_stateid))
                goto out_noupdate;
        if (!nfs4_stateid_is_newer(stateid, &lsp->ls_stateid))
                goto out_noupdate;
        nfs4_stateid_copy(&lsp->ls_stateid, stateid);
        ret = true;
out_noupdate:
        spin_unlock(&state->state_lock);
        return ret;
}

static void nfs4_return_incompatible_delegation(struct inode *inode, fmode_t fmode)
{
        struct nfs_delegation *delegation;

        rcu_read_lock();
        delegation = rcu_dereference(NFS_I(inode)->delegation);
        if (delegation == NULL || (delegation->type & fmode) == fmode) {
                rcu_read_unlock();
                return;
        }
        rcu_read_unlock();
        nfs4_inode_return_delegation(inode);
}

static struct nfs4_state *nfs4_try_open_cached(struct nfs4_opendata *opendata)
{
        struct nfs4_state *state = opendata->state;
        struct nfs_delegation *delegation;
        int open_mode = opendata->o_arg.open_flags;
        fmode_t fmode = opendata->o_arg.fmode;
        enum open_claim_type4 claim = opendata->o_arg.claim;
        nfs4_stateid stateid;
        int ret = -EAGAIN;

        for (;;) {
                spin_lock(&state->owner->so_lock);
                if (can_open_cached(state, fmode, open_mode, claim)) {
                        update_open_stateflags(state, fmode);
                        spin_unlock(&state->owner->so_lock);
                        goto out_return_state;
                }
                spin_unlock(&state->owner->so_lock);
                rcu_read_lock();
                delegation = nfs4_get_valid_delegation(state->inode);
                if (!can_open_delegated(delegation, fmode, claim)) {
                        rcu_read_unlock();
                        break;
                }
                /* Save the delegation */
                nfs4_stateid_copy(&stateid, &delegation->stateid);
                rcu_read_unlock();
                nfs_release_seqid(opendata->o_arg.seqid);
                if (!opendata->is_recover) {
                        ret = nfs_may_open(state->inode, state->owner->so_cred, open_mode);
                        if (ret != 0)
                                goto out;
                }
                ret = -EAGAIN;

                /* Try to update the stateid using the delegation */
                if (update_open_stateid(state, NULL, &stateid, fmode))
                        goto out_return_state;
        }
out:
        return ERR_PTR(ret);
out_return_state:
        atomic_inc(&state->count);
        return state;
}

static void
nfs4_opendata_check_deleg(struct nfs4_opendata *data, struct nfs4_state *state)
{
        struct nfs_client *clp = NFS_SERVER(state->inode)->nfs_client;
        struct nfs_delegation *delegation;
        int delegation_flags = 0;

        rcu_read_lock();
        delegation = rcu_dereference(NFS_I(state->inode)->delegation);
        if (delegation)
                delegation_flags = delegation->flags;
        rcu_read_unlock();
        switch (data->o_arg.claim) {
        default:
                break;
        case NFS4_OPEN_CLAIM_DELEGATE_CUR:
        case NFS4_OPEN_CLAIM_DELEG_CUR_FH:
                pr_err_ratelimited("NFS: Broken NFSv4 server %s is "
                                   "returning a delegation for "
                                   "OPEN(CLAIM_DELEGATE_CUR)\n",
                                   clp->cl_hostname);
                return;
        }
        if ((delegation_flags & 1UL<<NFS_DELEGATION_NEED_RECLAIM) == 0)
                nfs_inode_set_delegation(state->inode,
                                         data->owner->so_cred,
                                         &data->o_res);
        else
                nfs_inode_reclaim_delegation(state->inode,
                                             data->owner->so_cred,
                                             &data->o_res);
}

/*
 * Check the inode attributes against the CLAIM_PREVIOUS returned attributes
 * and update the nfs4_state.
 */
static struct nfs4_state *
_nfs4_opendata_reclaim_to_nfs4_state(struct nfs4_opendata *data)
{
        struct inode *inode = data->state->inode;
        struct nfs4_state *state = data->state;
        int ret;

        if (!data->rpc_done) {
                if (data->rpc_status)
                        return ERR_PTR(data->rpc_status);
                /* cached opens have already been processed */
                goto update;
        }

        ret = nfs_refresh_inode(inode, &data->f_attr);
        if (ret)
                return ERR_PTR(ret);

        if (data->o_res.delegation_type != 0)
                nfs4_opendata_check_deleg(data, state);
update:
        update_open_stateid(state, &data->o_res.stateid, NULL,
                            data->o_arg.fmode);
        atomic_inc(&state->count);

        return state;
}

static struct inode *
nfs4_opendata_get_inode(struct nfs4_opendata *data)
{
        struct inode *inode;

        switch (data->o_arg.claim) {
        case NFS4_OPEN_CLAIM_NULL:
        case NFS4_OPEN_CLAIM_DELEGATE_CUR:
        case NFS4_OPEN_CLAIM_DELEGATE_PREV:
                if (!(data->f_attr.valid & NFS_ATTR_FATTR))
                        return ERR_PTR(-EAGAIN);
                inode = nfs_fhget(data->dir->d_sb, &data->o_res.fh,
                                &data->f_attr, data->f_label);
                break;
        default:
                inode = d_inode(data->dentry);
                ihold(inode);
                nfs_refresh_inode(inode, &data->f_attr);
        }
        return inode;
}

static struct nfs4_state *
nfs4_opendata_find_nfs4_state(struct nfs4_opendata *data)
{
        struct nfs4_state *state;
        struct inode *inode;

        inode = nfs4_opendata_get_inode(data);
        if (IS_ERR(inode))
                return ERR_CAST(inode);
        if (data->state != NULL && data->state->inode == inode) {
                state = data->state;
                atomic_inc(&state->count);
        } else
                state = nfs4_get_open_state(inode, data->owner);
        iput(inode);
        if (state == NULL)
                state = ERR_PTR(-ENOMEM);
        return state;
}

static struct nfs4_state *
_nfs4_opendata_to_nfs4_state(struct nfs4_opendata *data)
{
        struct nfs4_state *state;

        if (!data->rpc_done) {
                state = nfs4_try_open_cached(data);
                trace_nfs4_cached_open(data->state);
                goto out;
        }

        state = nfs4_opendata_find_nfs4_state(data);
        if (IS_ERR(state))
                goto out;

        if (data->o_res.delegation_type != 0)
                nfs4_opendata_check_deleg(data, state);
        update_open_stateid(state, &data->o_res.stateid, NULL,
                        data->o_arg.fmode);
out:
        nfs_release_seqid(data->o_arg.seqid);
        return state;
}

static struct nfs4_state *
nfs4_opendata_to_nfs4_state(struct nfs4_opendata *data)
{
        struct nfs4_state *ret;

        if (data->o_arg.claim == NFS4_OPEN_CLAIM_PREVIOUS)
                ret =_nfs4_opendata_reclaim_to_nfs4_state(data);
        else
                ret = _nfs4_opendata_to_nfs4_state(data);
        nfs4_sequence_free_slot(&data->o_res.seq_res);
        return ret;
}

static struct nfs_open_context *nfs4_state_find_open_context(struct nfs4_state *state)
{
        struct nfs_inode *nfsi = NFS_I(state->inode);
        struct nfs_open_context *ctx;

        spin_lock(&state->inode->i_lock);
        list_for_each_entry(ctx, &nfsi->open_files, list) {
                if (ctx->state != state)
                        continue;
                get_nfs_open_context(ctx);
                spin_unlock(&state->inode->i_lock);
                return ctx;
        }
        spin_unlock(&state->inode->i_lock);
        return ERR_PTR(-ENOENT);
}

static struct nfs4_opendata *nfs4_open_recoverdata_alloc(struct nfs_open_context *ctx,
                struct nfs4_state *state, enum open_claim_type4 claim)
{
        struct nfs4_opendata *opendata;

        opendata = nfs4_opendata_alloc(ctx->dentry, state->owner, 0, 0,
                        NULL, claim, GFP_NOFS);
        if (opendata == NULL)
                return ERR_PTR(-ENOMEM);
        opendata->state = state;
        atomic_inc(&state->count);
        return opendata;
}

static int nfs4_open_recover_helper(struct nfs4_opendata *opendata,
                fmode_t fmode)
{
        struct nfs4_state *newstate;
        int ret;

        if (!nfs4_mode_match_open_stateid(opendata->state, fmode))
                return 0;
        opendata->o_arg.open_flags = 0;
        opendata->o_arg.fmode = fmode;
        opendata->o_arg.share_access = nfs4_map_atomic_open_share(
                        NFS_SB(opendata->dentry->d_sb),
                        fmode, 0);
        memset(&opendata->o_res, 0, sizeof(opendata->o_res));
        memset(&opendata->c_res, 0, sizeof(opendata->c_res));
        nfs4_init_opendata_res(opendata);
        ret = _nfs4_recover_proc_open(opendata);
        if (ret != 0)
                return ret; 
        newstate = nfs4_opendata_to_nfs4_state(opendata);
        if (IS_ERR(newstate))
                return PTR_ERR(newstate);
        if (newstate != opendata->state)
                ret = -ESTALE;
        nfs4_close_state(newstate, fmode);
        return ret;
}

static int nfs4_open_recover(struct nfs4_opendata *opendata, struct nfs4_state *state)
{
        int ret;

        /* Don't trigger recovery in nfs_test_and_clear_all_open_stateid */
        clear_bit(NFS_O_RDWR_STATE, &state->flags);
        clear_bit(NFS_O_WRONLY_STATE, &state->flags);
        clear_bit(NFS_O_RDONLY_STATE, &state->flags);
        /* memory barrier prior to reading state->n_* */
        clear_bit(NFS_DELEGATED_STATE, &state->flags);
        clear_bit(NFS_OPEN_STATE, &state->flags);
        smp_rmb();
        ret = nfs4_open_recover_helper(opendata, FMODE_READ|FMODE_WRITE);
        if (ret != 0)
                return ret;
        ret = nfs4_open_recover_helper(opendata, FMODE_WRITE);
        if (ret != 0)
                return ret;
        ret = nfs4_open_recover_helper(opendata, FMODE_READ);
        if (ret != 0)
                return ret;
        /*
         * We may have performed cached opens for all three recoveries.
         * Check if we need to update the current stateid.
         */
        if (test_bit(NFS_DELEGATED_STATE, &state->flags) == 0 &&
            !nfs4_stateid_match(&state->stateid, &state->open_stateid)) {
                write_seqlock(&state->seqlock);
                if (test_bit(NFS_DELEGATED_STATE, &state->flags) == 0)
                        nfs4_stateid_copy(&state->stateid, &state->open_stateid);
                write_sequnlock(&state->seqlock);
        }
        return 0;
}

/*
 * OPEN_RECLAIM:
 *      reclaim state on the server after a reboot.
 */
static int _nfs4_do_open_reclaim(struct nfs_open_context *ctx, struct nfs4_state *state)
{
        struct nfs_delegation *delegation;
        struct nfs4_opendata *opendata;
        fmode_t delegation_type = 0;
        int status;

        opendata = nfs4_open_recoverdata_alloc(ctx, state,
                        NFS4_OPEN_CLAIM_PREVIOUS);
        if (IS_ERR(opendata))
                return PTR_ERR(opendata);
        rcu_read_lock();
        delegation = rcu_dereference(NFS_I(state->inode)->delegation);
        if (delegation != NULL && test_bit(NFS_DELEGATION_NEED_RECLAIM, &delegation->flags) != 0)
                delegation_type = delegation->type;
        rcu_read_unlock();
        opendata->o_arg.u.delegation_type = delegation_type;
        status = nfs4_open_recover(opendata, state);
        nfs4_opendata_put(opendata);
        return status;
}

static int nfs4_do_open_reclaim(struct nfs_open_context *ctx, struct nfs4_state *state)
{
        struct nfs_server *server = NFS_SERVER(state->inode);
        struct nfs4_exception exception = { };
        int err;
        do {
                err = _nfs4_do_open_reclaim(ctx, state);
                trace_nfs4_open_reclaim(ctx, 0, err);
                if (nfs4_clear_cap_atomic_open_v1(server, err, &exception))
                        continue;
                if (err != -NFS4ERR_DELAY)
                        break;
                nfs4_handle_exception(server, err, &exception);
        } while (exception.retry);
        return err;
}

static int nfs4_open_reclaim(struct nfs4_state_owner *sp, struct nfs4_state *state)
{
        struct nfs_open_context *ctx;
        int ret;

        ctx = nfs4_state_find_open_context(state);
        if (IS_ERR(ctx))
                return -EAGAIN;
        ret = nfs4_do_open_reclaim(ctx, state);
        put_nfs_open_context(ctx);
        return ret;
}

static int nfs4_handle_delegation_recall_error(struct nfs_server *server, struct nfs4_state *state, const nfs4_stateid *stateid, struct file_lock *fl, int err)
{
        switch (err) {
                default:
                        printk(KERN_ERR "NFS: %s: unhandled error "
                                        "%d.\n", __func__, err);
                case 0:
                case -ENOENT:
                case -EAGAIN:
                case -ESTALE:
                        break;
                case -NFS4ERR_BADSESSION:
                case -NFS4ERR_BADSLOT:
                case -NFS4ERR_BAD_HIGH_SLOT:
                case -NFS4ERR_CONN_NOT_BOUND_TO_SESSION:
                case -NFS4ERR_DEADSESSION:
                        set_bit(NFS_DELEGATED_STATE, &state->flags);
                        nfs4_schedule_session_recovery(server->nfs_client->cl_session, err);
                        return -EAGAIN;
                case -NFS4ERR_STALE_CLIENTID:
                case -NFS4ERR_STALE_STATEID:
                        set_bit(NFS_DELEGATED_STATE, &state->flags);
                        /* Don't recall a delegation if it was lost */
                        nfs4_schedule_lease_recovery(server->nfs_client);
                        return -EAGAIN;
                case -NFS4ERR_MOVED:
                        nfs4_schedule_migration_recovery(server);
                        return -EAGAIN;
                case -NFS4ERR_LEASE_MOVED:
                        nfs4_schedule_lease_moved_recovery(server->nfs_client);
                        return -EAGAIN;
                case -NFS4ERR_DELEG_REVOKED:
                case -NFS4ERR_ADMIN_REVOKED:
                case -NFS4ERR_EXPIRED:
                case -NFS4ERR_BAD_STATEID:
                case -NFS4ERR_OPENMODE:
                        nfs_inode_find_state_and_recover(state->inode,
                                        stateid);
                        nfs4_schedule_stateid_recovery(server, state);
                        return -EAGAIN;
                case -NFS4ERR_DELAY:
                case -NFS4ERR_GRACE:
                        set_bit(NFS_DELEGATED_STATE, &state->flags);
                        ssleep(1);
                        return -EAGAIN;
                case -ENOMEM:
                case -NFS4ERR_DENIED:
                        if (fl) {
                                struct nfs4_lock_state *lsp = fl->fl_u.nfs4_fl.owner;
                                if (lsp)
                                        set_bit(NFS_LOCK_LOST, &lsp->ls_flags);
                        }
                        return 0;
        }
        return err;
}

int nfs4_open_delegation_recall(struct nfs_open_context *ctx,
                struct nfs4_state *state, const nfs4_stateid *stateid,
                fmode_t type)
{
        struct nfs_server *server = NFS_SERVER(state->inode);
        struct nfs4_opendata *opendata;
        int err = 0;

        opendata = nfs4_open_recoverdata_alloc(ctx, state,
                        NFS4_OPEN_CLAIM_DELEG_CUR_FH);
        if (IS_ERR(opendata))
                return PTR_ERR(opendata);
        nfs4_stateid_copy(&opendata->o_arg.u.delegation, stateid);
        write_seqlock(&state->seqlock);
        nfs4_stateid_copy(&state->stateid, &state->open_stateid);
        write_sequnlock(&state->seqlock);
        clear_bit(NFS_DELEGATED_STATE, &state->flags);
        switch (type & (FMODE_READ|FMODE_WRITE)) {
        case FMODE_READ|FMODE_WRITE:
        case FMODE_WRITE:
                err = nfs4_open_recover_helper(opendata, FMODE_READ|FMODE_WRITE);
                if (err)
                        break;
                err = nfs4_open_recover_helper(opendata, FMODE_WRITE);
                if (err)
                        break;
        case FMODE_READ:
                err = nfs4_open_recover_helper(opendata, FMODE_READ);
        }
        nfs4_opendata_put(opendata);
        return nfs4_handle_delegation_recall_error(server, state, stateid, NULL, err);
}

static void nfs4_open_confirm_prepare(struct rpc_task *task, void *calldata)
{
        struct nfs4_opendata *data = calldata;

        nfs4_setup_sequence(data->o_arg.server->nfs_client,
                           &data->c_arg.seq_args, &data->c_res.seq_res, task);
}

static void nfs4_open_confirm_done(struct rpc_task *task, void *calldata)
{
        struct nfs4_opendata *data = calldata;

        nfs40_sequence_done(task, &data->c_res.seq_res);

        data->rpc_status = task->tk_status;
        if (data->rpc_status == 0) {
                nfs4_stateid_copy(&data->o_res.stateid, &data->c_res.stateid);
                nfs_confirm_seqid(&data->owner->so_seqid, 0);
                renew_lease(data->o_res.server, data->timestamp);
                data->rpc_done = true;
        }
}

static void nfs4_open_confirm_release(void *calldata)
{
        struct nfs4_opendata *data = calldata;
        struct nfs4_state *state = NULL;

        /* If this request hasn't been cancelled, do nothing */
        if (!data->cancelled)
                goto out_free;
        /* In case of error, no cleanup! */
        if (!data->rpc_done)
                goto out_free;
        state = nfs4_opendata_to_nfs4_state(data);
        if (!IS_ERR(state))
                nfs4_close_state(state, data->o_arg.fmode);
out_free:
        nfs4_opendata_put(data);
}

static const struct rpc_call_ops nfs4_open_confirm_ops = {
        .rpc_call_prepare = nfs4_open_confirm_prepare,
        .rpc_call_done = nfs4_open_confirm_done,
        .rpc_release = nfs4_open_confirm_release,
};

/*
 * Note: On error, nfs4_proc_open_confirm will free the struct nfs4_opendata
 */
static int _nfs4_proc_open_confirm(struct nfs4_opendata *data)
{
        struct nfs_server *server = NFS_SERVER(d_inode(data->dir));
        struct rpc_task *task;
        struct  rpc_message msg = {
                .rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_OPEN_CONFIRM],
                .rpc_argp = &data->c_arg,
                .rpc_resp = &data->c_res,
                .rpc_cred = data->owner->so_cred,
        };
        struct rpc_task_setup task_setup_data = {
                .rpc_client = server->client,
                .rpc_message = &msg,
                .callback_ops = &nfs4_open_confirm_ops,
                .callback_data = data,
                .workqueue = nfsiod_workqueue,
                .flags = RPC_TASK_ASYNC,
        };
        int status;

        nfs4_init_sequence(&data->c_arg.seq_args, &data->c_res.seq_res, 1);
        kref_get(&data->kref);
        data->rpc_done = false;
        data->rpc_status = 0;
        data->timestamp = jiffies;
        if (data->is_recover)
                nfs4_set_sequence_privileged(&data->c_arg.seq_args);
        task = rpc_run_task(&task_setup_data);
        if (IS_ERR(task))
                return PTR_ERR(task);
        status = rpc_wait_for_completion_task(task);
        if (status != 0) {
                data->cancelled = true;
                smp_wmb();
        } else
                status = data->rpc_status;
        rpc_put_task(task);
        return status;
}

static void nfs4_open_prepare(struct rpc_task *task, void *calldata)
{
        struct nfs4_opendata *data = calldata;
        struct nfs4_state_owner *sp = data->owner;
        struct nfs_client *clp = sp->so_server->nfs_client;
        enum open_claim_type4 claim = data->o_arg.claim;

        if (nfs_wait_on_sequence(data->o_arg.seqid, task) != 0)
                goto out_wait;
        /*
         * Check if we still need to send an OPEN call, or if we can use
         * a delegation instead.
         */
        if (data->state != NULL) {
                struct nfs_delegation *delegation;

                if (can_open_cached(data->state, data->o_arg.fmode,
                                        data->o_arg.open_flags, claim))
                        goto out_no_action;
                rcu_read_lock();
                delegation = nfs4_get_valid_delegation(data->state->inode);
                if (can_open_delegated(delegation, data->o_arg.fmode, claim))
                        goto unlock_no_action;
                rcu_read_unlock();
        }
        /* Update client id. */
        data->o_arg.clientid = clp->cl_clientid;
        switch (claim) {
        default:
                break;
        case NFS4_OPEN_CLAIM_PREVIOUS:
        case NFS4_OPEN_CLAIM_DELEG_CUR_FH:
        case NFS4_OPEN_CLAIM_DELEG_PREV_FH:
                data->o_arg.open_bitmap = &nfs4_open_noattr_bitmap[0];
        case NFS4_OPEN_CLAIM_FH:
                task->tk_msg.rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_OPEN_NOATTR];
        }
        data->timestamp = jiffies;
        if (nfs4_setup_sequence(data->o_arg.server->nfs_client,
                                &data->o_arg.seq_args,
                                &data->o_res.seq_res,
                                task) != 0)
                nfs_release_seqid(data->o_arg.seqid);

        /* Set the create mode (note dependency on the session type) */
        data->o_arg.createmode = NFS4_CREATE_UNCHECKED;
        if (data->o_arg.open_flags & O_EXCL) {
                data->o_arg.createmode = NFS4_CREATE_EXCLUSIVE;
                if (nfs4_has_persistent_session(clp))
                        data->o_arg.createmode = NFS4_CREATE_GUARDED;
                else if (clp->cl_mvops->minor_version > 0)
                        data->o_arg.createmode = NFS4_CREATE_EXCLUSIVE4_1;
        }
        return;
unlock_no_action:
        trace_nfs4_cached_open(data->state);
        rcu_read_unlock();
out_no_action:
        task->tk_action = NULL;
out_wait:
        nfs4_sequence_done(task, &data->o_res.seq_res);
}

static void nfs4_open_done(struct rpc_task *task, void *calldata)
{
        struct nfs4_opendata *data = calldata;

        data->rpc_status = task->tk_status;

        if (!nfs4_sequence_process(task, &data->o_res.seq_res))
                return;

        if (task->tk_status == 0) {
                if (data->o_res.f_attr->valid & NFS_ATTR_FATTR_TYPE) {
                        switch (data->o_res.f_attr->mode & S_IFMT) {
                        case S_IFREG:
                                break;
                        case S_IFLNK:
                                data->rpc_status = -ELOOP;
                                break;
                        case S_IFDIR:
                                data->rpc_status = -EISDIR;
                                break;
                        default:
                                data->rpc_status = -ENOTDIR;
                        }
                }
                renew_lease(data->o_res.server, data->timestamp);
                if (!(data->o_res.rflags & NFS4_OPEN_RESULT_CONFIRM))
                        nfs_confirm_seqid(&data->owner->so_seqid, 0);
        }
        data->rpc_done = true;
}

static void nfs4_open_release(void *calldata)
{
        struct nfs4_opendata *data = calldata;
        struct nfs4_state *state = NULL;

        /* If this request hasn't been cancelled, do nothing */
        if (!data->cancelled)
                goto out_free;
        /* In case of error, no cleanup! */
        if (data->rpc_status != 0 || !data->rpc_done)
                goto out_free;
        /* In case we need an open_confirm, no cleanup! */
        if (data->o_res.rflags & NFS4_OPEN_RESULT_CONFIRM)
                goto out_free;
        state = nfs4_opendata_to_nfs4_state(data);
        if (!IS_ERR(state))
                nfs4_close_state(state, data->o_arg.fmode);
out_free:
        nfs4_opendata_put(data);
}

static const struct rpc_call_ops nfs4_open_ops = {
        .rpc_call_prepare = nfs4_open_prepare,
        .rpc_call_done = nfs4_open_done,
        .rpc_release = nfs4_open_release,
};

static int nfs4_run_open_task(struct nfs4_opendata *data, int isrecover)
{
        struct inode *dir = d_inode(data->dir);
        struct nfs_server *server = NFS_SERVER(dir);
        struct nfs_openargs *o_arg = &data->o_arg;
        struct nfs_openres *o_res = &data->o_res;
        struct rpc_task *task;
        struct rpc_message msg = {
                .rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_OPEN],
                .rpc_argp = o_arg,
                .rpc_resp = o_res,
                .rpc_cred = data->owner->so_cred,
        };
        struct rpc_task_setup task_setup_data = {
                .rpc_client = server->client,
                .rpc_message = &msg,
                .callback_ops = &nfs4_open_ops,
                .callback_data = data,
                .workqueue = nfsiod_workqueue,
                .flags = RPC_TASK_ASYNC,
        };
        int status;

        nfs4_init_sequence(&o_arg->seq_args, &o_res->seq_res, 1);
        kref_get(&data->kref);
        data->rpc_done = false;
        data->rpc_status = 0;
        data->cancelled = false;
        data->is_recover = false;
        if (isrecover) {
                nfs4_set_sequence_privileged(&o_arg->seq_args);
                data->is_recover = true;
        }
        task = rpc_run_task(&task_setup_data);
        if (IS_ERR(task))
                return PTR_ERR(task);
        status = rpc_wait_for_completion_task(task);
        if (status != 0) {
                data->cancelled = true;
                smp_wmb();
        } else
                status = data->rpc_status;
        rpc_put_task(task);

        return status;
}

static int _nfs4_recover_proc_open(struct nfs4_opendata *data)
{
        struct inode *dir = d_inode(data->dir);
        struct nfs_openres *o_res = &data->o_res;
        int status;

        status = nfs4_run_open_task(data, 1);
        if (status != 0 || !data->rpc_done)
                return status;

        nfs_fattr_map_and_free_names(NFS_SERVER(dir), &data->f_attr);

        if (o_res->rflags & NFS4_OPEN_RESULT_CONFIRM)
                status = _nfs4_proc_open_confirm(data);

        return status;
}

/*
 * Additional permission checks in order to distinguish between an
 * open for read, and an open for execute. This works around the
 * fact that NFSv4 OPEN treats read and execute permissions as being
 * the same.
 * Note that in the non-execute case, we want to turn off permission
 * checking if we just created a new file (POSIX open() semantics).
 */
static int nfs4_opendata_access(struct rpc_cred *cred,
                                struct nfs4_opendata *opendata,
                                struct nfs4_state *state, fmode_t fmode,
                                int openflags)
{
        struct nfs_access_entry cache;
        u32 mask, flags;

        /* access call failed or for some reason the server doesn't
         * support any access modes -- defer access call until later */
        if (opendata->o_res.access_supported == 0)
                return 0;

        mask = 0;
        /*
         * Use openflags to check for exec, because fmode won't
         * always have FMODE_EXEC set when file open for exec.
         */
        if (openflags & __FMODE_EXEC) {
                /* ONLY check for exec rights */
                if (S_ISDIR(state->inode->i_mode))
                        mask = NFS4_ACCESS_LOOKUP;
                else
                        mask = NFS4_ACCESS_EXECUTE;
        } else if ((fmode & FMODE_READ) && !opendata->file_created)
                mask = NFS4_ACCESS_READ;

        cache.cred = cred;
        nfs_access_set_mask(&cache, opendata->o_res.access_result);
        nfs_access_add_cache(state->inode, &cache);

        flags = NFS4_ACCESS_READ | NFS4_ACCESS_EXECUTE | NFS4_ACCESS_LOOKUP;
        if ((mask & ~cache.mask & flags) == 0)
                return 0;

        return -EACCES;
}

/*
 * Note: On error, nfs4_proc_open will free the struct nfs4_opendata
 */
static int _nfs4_proc_open(struct nfs4_opendata *data)
{
        struct inode *dir = d_inode(data->dir);
        struct nfs_server *server = NFS_SERVER(dir);
        struct nfs_openargs *o_arg = &data->o_arg;
        struct nfs_openres *o_res = &data->o_res;
        int status;

        status = nfs4_run_open_task(data, 0);
        if (!data->rpc_done)
                return status;
        if (status != 0) {
                if (status == -NFS4ERR_BADNAME &&
                                !(o_arg->open_flags & O_CREAT))
                        return -ENOENT;
                return status;
        }

        nfs_fattr_map_and_free_names(server, &data->f_attr);

        if (o_arg->open_flags & O_CREAT) {
                if (o_arg->open_flags & O_EXCL)
                        data->file_created = true;
                else if (o_res->cinfo.before != o_res->cinfo.after)
                        data->file_created = true;
                if (data->file_created || dir->i_version != o_res->cinfo.after)
                        update_changeattr(dir, &o_res->cinfo,
                                        o_res->f_attr->time_start);
        }
        if ((o_res->rflags & NFS4_OPEN_RESULT_LOCKTYPE_POSIX) == 0)
                server->caps &= ~NFS_CAP_POSIX_LOCK;
        if(o_res->rflags & NFS4_OPEN_RESULT_CONFIRM) {
                status = _nfs4_proc_open_confirm(data);
                if (status != 0)
                        return status;
        }
        if (!(o_res->f_attr->valid & NFS_ATTR_FATTR)) {
                nfs4_sequence_free_slot(&o_res->seq_res);
                nfs4_proc_getattr(server, &o_res->fh, o_res->f_attr, o_res->f_label);
        }
        return 0;
}

/*
 * OPEN_EXPIRED:
 *      reclaim state on the server after a network partition.
 *      Assumes caller holds the appropriate lock
 */
static int _nfs4_open_expired(struct nfs_open_context *ctx, struct nfs4_state *state)
{
        struct nfs4_opendata *opendata;
        int ret;

        opendata = nfs4_open_recoverdata_alloc(ctx, state,
                        NFS4_OPEN_CLAIM_FH);
        if (IS_ERR(opendata))
                return PTR_ERR(opendata);
        ret = nfs4_open_recover(opendata, state);
        if (ret == -ESTALE)
                d_drop(ctx->dentry);
        nfs4_opendata_put(opendata);
        return ret;
}

static int nfs4_do_open_expired(struct nfs_open_context *ctx, struct nfs4_state *state)
{
        struct nfs_server *server = NFS_SERVER(state->inode);
        struct nfs4_exception exception = { };
        int err;

        do {
                err = _nfs4_open_expired(ctx, state);
                trace_nfs4_open_expired(ctx, 0, err);
                if (nfs4_clear_cap_atomic_open_v1(server, err, &exception))
                        continue;
                switch (err) {
                default:
                        goto out;
                case -NFS4ERR_GRACE:
                case -NFS4ERR_DELAY:
                        nfs4_handle_exception(server, err, &exception);
                        err = 0;
                }
        } while (exception.retry);
out:
        return err;
}

static int nfs4_open_expired(struct nfs4_state_owner *sp, struct nfs4_state *state)
{
        struct nfs_open_context *ctx;
        int ret;

        ctx = nfs4_state_find_open_context(state);
        if (IS_ERR(ctx))
                return -EAGAIN;
        ret = nfs4_do_open_expired(ctx, state);
        put_nfs_open_context(ctx);
        return ret;
}

static void nfs_finish_clear_delegation_stateid(struct nfs4_state *state,
                const nfs4_stateid *stateid)
{
        nfs_remove_bad_delegation(state->inode, stateid);
        write_seqlock(&state->seqlock);
        nfs4_stateid_copy(&state->stateid, &state->open_stateid);
        write_sequnlock(&state->seqlock);
        clear_bit(NFS_DELEGATED_STATE, &state->flags);
}

static void nfs40_clear_delegation_stateid(struct nfs4_state *state)
{
        if (rcu_access_pointer(NFS_I(state->inode)->delegation) != NULL)
                nfs_finish_clear_delegation_stateid(state, NULL);
}

static int nfs40_open_expired(struct nfs4_state_owner *sp, struct nfs4_state *state)
{
        /* NFSv4.0 doesn't allow for delegation recovery on open expire */
        nfs40_clear_delegation_stateid(state);
        return nfs4_open_expired(sp, state);
}

static int nfs40_test_and_free_expired_stateid(struct nfs_server *server,
                nfs4_stateid *stateid,
                struct rpc_cred *cred)
{
        return -NFS4ERR_BAD_STATEID;
}

#if defined(CONFIG_NFS_V4_1)
static int nfs41_test_and_free_expired_stateid(struct nfs_server *server,
                nfs4_stateid *stateid,
                struct rpc_cred *cred)
{
        int status;

        switch (stateid->type) {
        default:
                break;
        case NFS4_INVALID_STATEID_TYPE:
        case NFS4_SPECIAL_STATEID_TYPE:
                return -NFS4ERR_BAD_STATEID;
        case NFS4_REVOKED_STATEID_TYPE:
                goto out_free;
        }

        status = nfs41_test_stateid(server, stateid, cred);
        switch (status) {
        case -NFS4ERR_EXPIRED:
        case -NFS4ERR_ADMIN_REVOKED:
        case -NFS4ERR_DELEG_REVOKED:
                break;
        default:
                return status;
        }
out_free:
        /* Ack the revoked state to the server */
        nfs41_free_stateid(server, stateid, cred, true);
        return -NFS4ERR_EXPIRED;
}

static void nfs41_check_delegation_stateid(struct nfs4_state *state)
{
        struct nfs_server *server = NFS_SERVER(state->inode);
        nfs4_stateid stateid;
        struct nfs_delegation *delegation;
        struct rpc_cred *cred;
        int status;

        /* Get the delegation credential for use by test/free_stateid */
        rcu_read_lock();
        delegation = rcu_dereference(NFS_I(state->inode)->delegation);
        if (delegation == NULL) {
                rcu_read_unlock();
                return;
        }

        nfs4_stateid_copy(&stateid, &delegation->stateid);
        if (test_bit(NFS_DELEGATION_REVOKED, &delegation->flags)) {
                rcu_read_unlock();
                nfs_finish_clear_delegation_stateid(state, &stateid);
                return;
        }

        if (!test_and_clear_bit(NFS_DELEGATION_TEST_EXPIRED,
                                &delegation->flags)) {
                rcu_read_unlock();
                return;
        }

        cred = get_rpccred(delegation->cred);
        rcu_read_unlock();
        status = nfs41_test_and_free_expired_stateid(server, &stateid, cred);
        trace_nfs4_test_delegation_stateid(state, NULL, status);
        if (status == -NFS4ERR_EXPIRED || status == -NFS4ERR_BAD_STATEID)
                nfs_finish_clear_delegation_stateid(state, &stateid);

        put_rpccred(cred);
}

/**
 * nfs41_check_expired_locks - possibly free a lock stateid
 *
 * @state: NFSv4 state for an inode
 *
 * Returns NFS_OK if recovery for this stateid is now finished.
 * Otherwise a negative NFS4ERR value is returned.
 */
static int nfs41_check_expired_locks(struct nfs4_state *state)
{
        int status, ret = NFS_OK;
        struct nfs4_lock_state *lsp, *prev = NULL;
        struct nfs_server *server = NFS_SERVER(state->inode);

        if (!test_bit(LK_STATE_IN_USE, &state->flags))
                goto out;

        spin_lock(&state->state_lock);
        list_for_each_entry(lsp, &state->lock_states, ls_locks) {
                if (test_bit(NFS_LOCK_INITIALIZED, &lsp->ls_flags)) {
                        struct rpc_cred *cred = lsp->ls_state->owner->so_cred;

                        atomic_inc(&lsp->ls_count);
                        spin_unlock(&state->state_lock);

                        nfs4_put_lock_state(prev);
                        prev = lsp;

                        status = nfs41_test_and_free_expired_stateid(server,
                                        &lsp->ls_stateid,
                                        cred);
                        trace_nfs4_test_lock_stateid(state, lsp, status);
                        if (status == -NFS4ERR_EXPIRED ||
                            status == -NFS4ERR_BAD_STATEID) {
                                clear_bit(NFS_LOCK_INITIALIZED, &lsp->ls_flags);
                                lsp->ls_stateid.type = NFS4_INVALID_STATEID_TYPE;
                                if (!recover_lost_locks)
                                        set_bit(NFS_LOCK_LOST, &lsp->ls_flags);
                        } else if (status != NFS_OK) {
                                ret = status;
                                nfs4_put_lock_state(prev);
                                goto out;
                        }
                        spin_lock(&state->state_lock);
                }
        }
        spin_unlock(&state->state_lock);
        nfs4_put_lock_state(prev);
out:
        return ret;
}

/**
 * nfs41_check_open_stateid - possibly free an open stateid
 *
 * @state: NFSv4 state for an inode
 *
 * Returns NFS_OK if recovery for this stateid is now finished.
 * Otherwise a negative NFS4ERR value is returned.
 */
static int nfs41_check_open_stateid(struct nfs4_state *state)
{
        struct nfs_server *server = NFS_SERVER(state->inode);
        nfs4_stateid *stateid = &state->open_stateid;
        struct rpc_cred *cred = state->owner->so_cred;
        int status;

        if (test_bit(NFS_OPEN_STATE, &state->flags) == 0) {
                if (test_bit(NFS_DELEGATED_STATE, &state->flags) == 0)  {
                        if (nfs4_have_delegation(state->inode, state->state))
                                return NFS_OK;
                        return -NFS4ERR_OPENMODE;
                }
                return -NFS4ERR_BAD_STATEID;
        }
        status = nfs41_test_and_free_expired_stateid(server, stateid, cred);
        trace_nfs4_test_open_stateid(state, NULL, status);
        if (status == -NFS4ERR_EXPIRED || status == -NFS4ERR_BAD_STATEID) {
                clear_bit(NFS_O_RDONLY_STATE, &state->flags);
                clear_bit(NFS_O_WRONLY_STATE, &state->flags);
                clear_bit(NFS_O_RDWR_STATE, &state->flags);
                clear_bit(NFS_OPEN_STATE, &state->flags);
                stateid->type = NFS4_INVALID_STATEID_TYPE;
                return status;
        }
        if (nfs_open_stateid_recover_openmode(state))
                return -NFS4ERR_OPENMODE;
        return NFS_OK;
}

static int nfs41_open_expired(struct nfs4_state_owner *sp, struct nfs4_state *state)
{
        int status;

        nfs41_check_delegation_stateid(state);
        status = nfs41_check_expired_locks(state);
        if (status != NFS_OK)
                return status;
        status = nfs41_check_open_stateid(state);
        if (status != NFS_OK)
                status = nfs4_open_expired(sp, state);
        return status;
}
#endif

/*
 * on an EXCLUSIVE create, the server should send back a bitmask with FATTR4-*
 * fields corresponding to attributes that were used to store the verifier.
 * Make sure we clobber those fields in the later setattr call
 */
static inline void nfs4_exclusive_attrset(struct nfs4_opendata *opendata,
                                struct iattr *sattr, struct nfs4_label **label)
{
        const u32 *attrset = opendata->o_res.attrset;

        if ((attrset[1] & FATTR4_WORD1_TIME_ACCESS) &&
            !(sattr->ia_valid & ATTR_ATIME_SET))
                sattr->ia_valid |= ATTR_ATIME;

        if ((attrset[1] & FATTR4_WORD1_TIME_MODIFY) &&
            !(sattr->ia_valid & ATTR_MTIME_SET))
                sattr->ia_valid |= ATTR_MTIME;

        /* Except MODE, it seems harmless of setting twice. */
        if (opendata->o_arg.createmode != NFS4_CREATE_EXCLUSIVE &&
                (attrset[1] & FATTR4_WORD1_MODE ||
                 attrset[2] & FATTR4_WORD2_MODE_UMASK))
                sattr->ia_valid &= ~ATTR_MODE;

        if (attrset[2] & FATTR4_WORD2_SECURITY_LABEL)
                *label = NULL;
}

static int _nfs4_open_and_get_state(struct nfs4_opendata *opendata,
                fmode_t fmode,
                int flags,
                struct nfs_open_context *ctx)
{
        struct nfs4_state_owner *sp = opendata->owner;
        struct nfs_server *server = sp->so_server;
        struct dentry *dentry;
        struct nfs4_state *state;
        unsigned int seq;
        int ret;

        seq = raw_seqcount_begin(&sp->so_reclaim_seqcount);

        ret = _nfs4_proc_open(opendata);
        if (ret != 0)
                goto out;

        state = _nfs4_opendata_to_nfs4_state(opendata);
        ret = PTR_ERR(state);
        if (IS_ERR(state))
                goto out;
        ctx->state = state;
        if (server->caps & NFS_CAP_POSIX_LOCK)
                set_bit(NFS_STATE_POSIX_LOCKS, &state->flags);
        if (opendata->o_res.rflags & NFS4_OPEN_RESULT_MAY_NOTIFY_LOCK)
                set_bit(NFS_STATE_MAY_NOTIFY_LOCK, &state->flags);

        dentry = opendata->dentry;
        if (d_really_is_negative(dentry)) {
                struct dentry *alias;
                d_drop(dentry);
                alias = d_exact_alias(dentry, state->inode);
                if (!alias)
                        alias = d_splice_alias(igrab(state->inode), dentry);
                /* d_splice_alias() can't fail here - it's a non-directory */
                if (alias) {
                        dput(ctx->dentry);
                        ctx->dentry = dentry = alias;
                }
                nfs_set_verifier(dentry,
                                nfs_save_change_attribute(d_inode(opendata->dir)));
        }

        ret = nfs4_opendata_access(sp->so_cred, opendata, state, fmode, flags);
        if (ret != 0)
                goto out;

        if (d_inode(dentry) == state->inode) {
                nfs_inode_attach_open_context(ctx);
                if (read_seqcount_retry(&sp->so_reclaim_seqcount, seq))
                        nfs4_schedule_stateid_recovery(server, state);
        }
out:
        if (!opendata->cancelled)
                nfs4_sequence_free_slot(&opendata->o_res.seq_res);
        return ret;
}

/*
 * Returns a referenced nfs4_state
 */
static int _nfs4_do_open(struct inode *dir,
                        struct nfs_open_context *ctx,
                        int flags,
                        const struct nfs4_open_createattrs *c,
                        int *opened)
{
        struct nfs4_state_owner  *sp;
        struct nfs4_state     *state = NULL;
        struct nfs_server       *server = NFS_SERVER(dir);
        struct nfs4_opendata *opendata;
        struct dentry *dentry = ctx->dentry;
        struct rpc_cred *cred = ctx->cred;
        struct nfs4_threshold **ctx_th = &ctx->mdsthreshold;
        fmode_t fmode = ctx->mode & (FMODE_READ|FMODE_WRITE|FMODE_EXEC);
        enum open_claim_type4 claim = NFS4_OPEN_CLAIM_NULL;
        struct iattr *sattr = c->sattr;
        struct nfs4_label *label = c->label;
        struct nfs4_label *olabel = NULL;
        int status;

        /* Protect against reboot recovery conflicts */
        status = -ENOMEM;
        sp = nfs4_get_state_owner(server, cred, GFP_KERNEL);
        if (sp == NULL) {
                dprintk("nfs4_do_open: nfs4_get_state_owner failed!\n");
                goto out_err;
        }
        status = nfs4_client_recover_expired_lease(server->nfs_client);
        if (status != 0)
                goto err_put_state_owner;
        if (d_really_is_positive(dentry))
                nfs4_return_incompatible_delegation(d_inode(dentry), fmode);
        status = -ENOMEM;
        if (d_really_is_positive(dentry))
                claim = NFS4_OPEN_CLAIM_FH;
        opendata = nfs4_opendata_alloc(dentry, sp, fmode, flags,
                        c, claim, GFP_KERNEL);
        if (opendata == NULL)
                goto err_put_state_owner;

        if (label) {
                olabel = nfs4_label_alloc(server, GFP_KERNEL);
                if (IS_ERR(olabel)) {
                        status = PTR_ERR(olabel);
                        goto err_opendata_put;
                }
        }

        if (server->attr_bitmask[2] & FATTR4_WORD2_MDSTHRESHOLD) {
                if (!opendata->f_attr.mdsthreshold) {
                        opendata->f_attr.mdsthreshold = pnfs_mdsthreshold_alloc();
                        if (!opendata->f_attr.mdsthreshold)
                                goto err_free_label;
                }
                opendata->o_arg.open_bitmap = &nfs4_pnfs_open_bitmap[0];
        }
        if (d_really_is_positive(dentry))
                opendata->state = nfs4_get_open_state(d_inode(dentry), sp);

        status = _nfs4_open_and_get_state(opendata, fmode, flags, ctx);
        if (status != 0)
                goto err_free_label;
        state = ctx->state;

        if ((opendata->o_arg.open_flags & (O_CREAT|O_EXCL)) == (O_CREAT|O_EXCL) &&
            (opendata->o_arg.createmode != NFS4_CREATE_GUARDED)) {
                nfs4_exclusive_attrset(opendata, sattr, &label);
                /*
                 * send create attributes which was not set by open
                 * with an extra setattr.
                 */
                if (sattr->ia_valid & NFS4_VALID_ATTRS) {
                        nfs_fattr_init(opendata->o_res.f_attr);
                        status = nfs4_do_setattr(state->inode, cred,
                                        opendata->o_res.f_attr, sattr,
                                        ctx, label, olabel);
                        if (status == 0) {
                                nfs_setattr_update_inode(state->inode, sattr,
                                                opendata->o_res.f_attr);
                                nfs_setsecurity(state->inode, opendata->o_res.f_attr, olabel);
                        }
                }
        }
        if (opened && opendata->file_created)
                *opened |= FILE_CREATED;

        if (pnfs_use_threshold(ctx_th, opendata->f_attr.mdsthreshold, server)) {
                *ctx_th = opendata->f_attr.mdsthreshold;
                opendata->f_attr.mdsthreshold = NULL;
        }

        nfs4_label_free(olabel);

        nfs4_opendata_put(opendata);
        nfs4_put_state_owner(sp);
        return 0;
err_free_label:
        nfs4_label_free(olabel);
err_opendata_put:
        nfs4_opendata_put(opendata);
err_put_state_owner:
        nfs4_put_state_owner(sp);
out_err:
        return status;
}


static struct nfs4_state *nfs4_do_open(struct inode *dir,
                                        struct nfs_open_context *ctx,
                                        int flags,
                                        struct iattr *sattr,
                                        struct nfs4_label *label,
                                        int *opened)
{
        struct nfs_server *server = NFS_SERVER(dir);
        struct nfs4_exception exception = { };
        struct nfs4_state *res;
        struct nfs4_open_createattrs c = {
                .label = label,
                .sattr = sattr,
                .verf = {
                        [0] = (__u32)jiffies,
                        [1] = (__u32)current->pid,
                },
        };
        int status;

        do {
                status = _nfs4_do_open(dir, ctx, flags, &c, opened);
                res = ctx->state;
                trace_nfs4_open_file(ctx, flags, status);
                if (status == 0)
                        break;
                /* NOTE: BAD_SEQID means the server and client disagree about the
                 * book-keeping w.r.t. state-changing operations
                 * (OPEN/CLOSE/LOCK/LOCKU...)
                 * It is actually a sign of a bug on the client or on the server.
                 *
                 * If we receive a BAD_SEQID error in the particular case of
                 * doing an OPEN, we assume that nfs_increment_open_seqid() will
                 * have unhashed the old state_owner for us, and that we can
                 * therefore safely retry using a new one. We should still warn
                 * the user though...
                 */
                if (status == -NFS4ERR_BAD_SEQID) {
                        pr_warn_ratelimited("NFS: v4 server %s "
                                        " returned a bad sequence-id error!\n",
                                        NFS_SERVER(dir)->nfs_client->cl_hostname);
                        exception.retry = 1;
                        continue;
                }
                /*
                 * BAD_STATEID on OPEN means that the server cancelled our
                 * state before it received the OPEN_CONFIRM.
                 * Recover by retrying the request as per the discussion
                 * on Page 181 of RFC3530.
                 */
                if (status == -NFS4ERR_BAD_STATEID) {
                        exception.retry = 1;
                        continue;
                }
                if (status == -NFS4ERR_EXPIRED) {
                        nfs4_schedule_lease_recovery(server->nfs_client);
                        exception.retry = 1;
                        continue;
                }
                if (status == -EAGAIN) {
                        /* We must have found a delegation */
                        exception.retry = 1;
                        continue;
                }
                if (nfs4_clear_cap_atomic_open_v1(server, status, &exception))
                        continue;
                res = ERR_PTR(nfs4_handle_exception(server,
                                        status, &exception));
        } while (exception.retry);
        return res;
}

static int _nfs4_do_setattr(struct inode *inode,
                            struct nfs_setattrargs *arg,
                            struct nfs_setattrres *res,
                            struct rpc_cred *cred,
                            struct nfs_open_context *ctx)
{
        struct nfs_server *server = NFS_SERVER(inode);
        struct rpc_message msg = {
                .rpc_proc       = &nfs4_procedures[NFSPROC4_CLNT_SETATTR],
                .rpc_argp       = arg,
                .rpc_resp       = res,
                .rpc_cred       = cred,
        };
        struct rpc_cred *delegation_cred = NULL;
        unsigned long timestamp = jiffies;
        bool truncate;
        int status;

        nfs_fattr_init(res->fattr);

        /* Servers should only apply open mode checks for file size changes */
        truncate = (arg->iap->ia_valid & ATTR_SIZE) ? true : false;
        if (!truncate)
                goto zero_stateid;

        if (nfs4_copy_delegation_stateid(inode, FMODE_WRITE, &arg->stateid, &delegation_cred)) {
                /* Use that stateid */
        } else if (ctx != NULL && ctx->state) {
                struct nfs_lock_context *l_ctx;
                if (!nfs4_valid_open_stateid(ctx->state))
                        return -EBADF;
                l_ctx = nfs_get_lock_context(ctx);
                if (IS_ERR(l_ctx))
                        return PTR_ERR(l_ctx);
                status = nfs4_select_rw_stateid(ctx->state, FMODE_WRITE, l_ctx,
                                                &arg->stateid, &delegation_cred);
                nfs_put_lock_context(l_ctx);
                if (status == -EIO)
                        return -EBADF;
        } else {
zero_stateid:
                nfs4_stateid_copy(&arg->stateid, &zero_stateid);
        }
        if (delegation_cred)
                msg.rpc_cred = delegation_cred;

        status = nfs4_call_sync(server->client, server, &msg, &arg->seq_args, &res->seq_res, 1);

        put_rpccred(delegation_cred);
        if (status == 0 && ctx != NULL)
                renew_lease(server, timestamp);
        trace_nfs4_setattr(inode, &arg->stateid, status);
        return status;
}

static int nfs4_do_setattr(struct inode *inode, struct rpc_cred *cred,
                           struct nfs_fattr *fattr, struct iattr *sattr,
                           struct nfs_open_context *ctx, struct nfs4_label *ilabel,
                           struct nfs4_label *olabel)
{
        struct nfs_server *server = NFS_SERVER(inode);
        struct nfs4_state *state = ctx ? ctx->state : NULL;
        struct nfs_setattrargs  arg = {
                .fh             = NFS_FH(inode),
                .iap            = sattr,
                .server         = server,
                .bitmask = server->attr_bitmask,
                .label          = ilabel,
        };
        struct nfs_setattrres  res = {
                .fattr          = fattr,
                .label          = olabel,
                .server         = server,
        };
        struct nfs4_exception exception = {
                .state = state,
                .inode = inode,
                .stateid = &arg.stateid,
        };
        int err;

        arg.bitmask = nfs4_bitmask(server, ilabel);
        if (ilabel)
                arg.bitmask = nfs4_bitmask(server, olabel);

        do {
                err = _nfs4_do_setattr(inode, &arg, &res, cred, ctx);
                switch (err) {
                case -NFS4ERR_OPENMODE:
                        if (!(sattr->ia_valid & ATTR_SIZE)) {
                                pr_warn_once("NFSv4: server %s is incorrectly "
                                                "applying open mode checks to "
                                                "a SETATTR that is not "
                                                "changing file size.\n",
                                                server->nfs_client->cl_hostname);
                        }
                        if (state && !(state->state & FMODE_WRITE)) {
                                err = -EBADF;
                                if (sattr->ia_valid & ATTR_OPEN)
                                        err = -EACCES;
                                goto out;
                        }
                }
                err = nfs4_handle_exception(server, err, &exception);
        } while (exception.retry);
out:
        return err;
}

static bool
nfs4_wait_on_layoutreturn(struct inode *inode, struct rpc_task *task)
{
        if (inode == NULL || !nfs_have_layout(inode))
                return false;

        return pnfs_wait_on_layoutreturn(inode, task);
}

struct nfs4_closedata {
        struct inode *inode;
        struct nfs4_state *state;
        struct nfs_closeargs arg;
        struct nfs_closeres res;
        struct {
                struct nfs4_layoutreturn_args arg;
                struct nfs4_layoutreturn_res res;
                struct nfs4_xdr_opaque_data ld_private;
                u32 roc_barrier;
                bool roc;
        } lr;
        struct nfs_fattr fattr;
        unsigned long timestamp;
};

static void nfs4_free_closedata(void *data)
{
        struct nfs4_closedata *calldata = data;
        struct nfs4_state_owner *sp = calldata->state->owner;
        struct super_block *sb = calldata->state->inode->i_sb;

        if (calldata->lr.roc)
                pnfs_roc_release(&calldata->lr.arg, &calldata->lr.res,
                                calldata->res.lr_ret);
        nfs4_put_open_state(calldata->state);
        nfs_free_seqid(calldata->arg.seqid);
        nfs4_put_state_owner(sp);
        nfs_sb_deactive(sb);
        kfree(calldata);
}

static void nfs4_close_done(struct rpc_task *task, void *data)
{
        struct nfs4_closedata *calldata = data;
        struct nfs4_state *state = calldata->state;
        struct nfs_server *server = NFS_SERVER(calldata->inode);
        nfs4_stateid *res_stateid = NULL;

        dprintk("%s: begin!\n", __func__);
        if (!nfs4_sequence_done(task, &calldata->res.seq_res))
                return;
        trace_nfs4_close(state, &calldata->arg, &calldata->res, task->tk_status);

        /* Handle Layoutreturn errors */
        if (calldata->arg.lr_args && task->tk_status != 0) {
                switch (calldata->res.lr_ret) {
                default:
                        calldata->res.lr_ret = -NFS4ERR_NOMATCHING_LAYOUT;
                        break;
                case 0:
                        calldata->arg.lr_args = NULL;
                        calldata->res.lr_res = NULL;
                        break;
                case -NFS4ERR_ADMIN_REVOKED:
                case -NFS4ERR_DELEG_REVOKED:
                case -NFS4ERR_EXPIRED:
                case -NFS4ERR_BAD_STATEID:
                case -NFS4ERR_OLD_STATEID:
                case -NFS4ERR_UNKNOWN_LAYOUTTYPE:
                case -NFS4ERR_WRONG_CRED:
                        calldata->arg.lr_args = NULL;
                        calldata->res.lr_res = NULL;
                        calldata->res.lr_ret = 0;
                        rpc_restart_call_prepare(task);
                        return;
                }
        }

        /* hmm. we are done with the inode, and in the process of freeing
         * the state_owner. we keep this around to process errors
         */
        switch (task->tk_status) {
                case 0:
                        res_stateid = &calldata->res.stateid;
                        renew_lease(server, calldata->timestamp);
                        break;
                case -NFS4ERR_ACCESS:
                        if (calldata->arg.bitmask != NULL) {
                                calldata->arg.bitmask = NULL;
                                calldata->res.fattr = NULL;
                                task->tk_status = 0;
                                rpc_restart_call_prepare(task);
                                goto out_release;

                        }
                        break;
                case -NFS4ERR_ADMIN_REVOKED:
                case -NFS4ERR_STALE_STATEID:
                case -NFS4ERR_EXPIRED:
                        nfs4_free_revoked_stateid(server,
                                        &calldata->arg.stateid,
                                        task->tk_msg.rpc_cred);
                case -NFS4ERR_OLD_STATEID:
                case -NFS4ERR_BAD_STATEID:
                        if (!nfs4_stateid_match(&calldata->arg.stateid,
                                                &state->open_stateid)) {
                                rpc_restart_call_prepare(task);
                                goto out_release;
                        }
                        if (calldata->arg.fmode == 0)
                                break;
                default:
                        if (nfs4_async_handle_error(task, server, state, NULL) == -EAGAIN) {
                                rpc_restart_call_prepare(task);
                                goto out_release;
                        }
        }
        nfs_clear_open_stateid(state, &calldata->arg.stateid,
                        res_stateid, calldata->arg.fmode);
out_release:
        nfs_release_seqid(calldata->arg.seqid);
        nfs_refresh_inode(calldata->inode, &calldata->fattr);
        dprintk("%s: done, ret = %d!\n", __func__, task->tk_status);
}

static void nfs4_close_prepare(struct rpc_task *task, void *data)
{
        struct nfs4_closedata *calldata = data;
        struct nfs4_state *state = calldata->state;
        struct inode *inode = calldata->inode;
        bool is_rdonly, is_wronly, is_rdwr;
        int call_close = 0;

        dprintk("%s: begin!\n", __func__);
        if (nfs_wait_on_sequence(calldata->arg.seqid, task) != 0)
                goto out_wait;

        task->tk_msg.rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_OPEN_DOWNGRADE];
        spin_lock(&state->owner->so_lock);
        is_rdwr = test_bit(NFS_O_RDWR_STATE, &state->flags);
        is_rdonly = test_bit(NFS_O_RDONLY_STATE, &state->flags);
        is_wronly = test_bit(NFS_O_WRONLY_STATE, &state->flags);
        nfs4_stateid_copy(&calldata->arg.stateid, &state->open_stateid);
        /* Calculate the change in open mode */
        calldata->arg.fmode = 0;
        if (state->n_rdwr == 0) {
                if (state->n_rdonly == 0)
                        call_close |= is_rdonly;
                else if (is_rdonly)
                        calldata->arg.fmode |= FMODE_READ;
                if (state->n_wronly == 0)
                        call_close |= is_wronly;
                else if (is_wronly)
                        calldata->arg.fmode |= FMODE_WRITE;
                if (calldata->arg.fmode != (FMODE_READ|FMODE_WRITE))
                        call_close |= is_rdwr;
        } else if (is_rdwr)
                calldata->arg.fmode |= FMODE_READ|FMODE_WRITE;

        if (!nfs4_valid_open_stateid(state) ||
            test_bit(NFS_OPEN_STATE, &state->flags) == 0)
                call_close = 0;
        spin_unlock(&state->owner->so_lock);

        if (!call_close) {
                /* Note: exit _without_ calling nfs4_close_done */
                goto out_no_action;
        }

        if (!calldata->lr.roc && nfs4_wait_on_layoutreturn(inode, task)) {
                nfs_release_seqid(calldata->arg.seqid);
                goto out_wait;
        }

        if (calldata->arg.fmode == 0)
                task->tk_msg.rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_CLOSE];

        if (calldata->arg.fmode == 0 || calldata->arg.fmode == FMODE_READ) {
                /* Close-to-open cache consistency revalidation */
                if (!nfs4_have_delegation(inode, FMODE_READ))
                        calldata->arg.bitmask = NFS_SERVER(inode)->cache_consistency_bitmask;
                else
                        calldata->arg.bitmask = NULL;
        }

        calldata->arg.share_access =
                nfs4_map_atomic_open_share(NFS_SERVER(inode),
                                calldata->arg.fmode, 0);

        if (calldata->res.fattr == NULL)
                calldata->arg.bitmask = NULL;
        else if (calldata->arg.bitmask == NULL)
                calldata->res.fattr = NULL;
        calldata->timestamp = jiffies;
        if (nfs4_setup_sequence(NFS_SERVER(inode)->nfs_client,
                                &calldata->arg.seq_args,
                                &calldata->res.seq_res,
                                task) != 0)
                nfs_release_seqid(calldata->arg.seqid);
        dprintk("%s: done!\n", __func__);
        return;
out_no_action:
        task->tk_action = NULL;
out_wait:
        nfs4_sequence_done(task, &calldata->res.seq_res);
}

static const struct rpc_call_ops nfs4_close_ops = {
        .rpc_call_prepare = nfs4_close_prepare,
        .rpc_call_done = nfs4_close_done,
        .rpc_release = nfs4_free_closedata,
};

/* 
 * It is possible for data to be read/written from a mem-mapped file 
 * after the sys_close call (which hits the vfs layer as a flush).
 * This means that we can't safely call nfsv4 close on a file until 
 * the inode is cleared. This in turn means that we are not good
 * NFSv4 citizens - we do not indicate to the server to update the file's 
 * share state even when we are done with one of the three share 
 * stateid's in the inode.
 *
 * NOTE: Caller must be holding the sp->so_owner semaphore!
 */
int nfs4_do_close(struct nfs4_state *state, gfp_t gfp_mask, int wait)
{
        struct nfs_server *server = NFS_SERVER(state->inode);
        struct nfs_seqid *(*alloc_seqid)(struct nfs_seqid_counter *, gfp_t);
        struct nfs4_closedata *calldata;
        struct nfs4_state_owner *sp = state->owner;
        struct rpc_task *task;
        struct rpc_message msg = {
                .rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_CLOSE],
                .rpc_cred = state->owner->so_cred,
        };
        struct rpc_task_setup task_setup_data = {
                .rpc_client = server->client,
                .rpc_message = &msg,
                .callback_ops = &nfs4_close_ops,
                .workqueue = nfsiod_workqueue,
                .flags = RPC_TASK_ASYNC,
        };
        int status = -ENOMEM;

        nfs4_state_protect(server->nfs_client, NFS_SP4_MACH_CRED_CLEANUP,
                &task_setup_data.rpc_client, &msg);

        calldata = kzalloc(sizeof(*calldata), gfp_mask);
        if (calldata == NULL)
                goto out;
        nfs4_init_sequence(&calldata->arg.seq_args, &calldata->res.seq_res, 1);
        calldata->inode = state->inode;
        calldata->state = state;
        calldata->arg.fh = NFS_FH(state->inode);
        /* Serialization for the sequence id */
        alloc_seqid = server->nfs_client->cl_mvops->alloc_seqid;
        calldata->arg.seqid = alloc_seqid(&state->owner->so_seqid, gfp_mask);
        if (IS_ERR(calldata->arg.seqid))
                goto out_free_calldata;
        nfs_fattr_init(&calldata->fattr);
        calldata->arg.fmode = 0;
        calldata->lr.arg.ld_private = &calldata->lr.ld_private;
        calldata->res.fattr = &calldata->fattr;
        calldata->res.seqid = calldata->arg.seqid;
        calldata->res.server = server;
        calldata->res.lr_ret = -NFS4ERR_NOMATCHING_LAYOUT;
        calldata->lr.roc = pnfs_roc(state->inode,
                        &calldata->lr.arg, &calldata->lr.res, msg.rpc_cred);
        if (calldata->lr.roc) {
                calldata->arg.lr_args = &calldata->lr.arg;
                calldata->res.lr_res = &calldata->lr.res;
        }
        nfs_sb_active(calldata->inode->i_sb);

        msg.rpc_argp = &calldata->arg;
        msg.rpc_resp = &calldata->res;
        task_setup_data.callback_data = calldata;
        task = rpc_run_task(&task_setup_data);
        if (IS_ERR(task))
                return PTR_ERR(task);
        status = 0;
        if (wait)
                status = rpc_wait_for_completion_task(task);
        rpc_put_task(task);
        return status;
out_free_calldata:
        kfree(calldata);
out:
        nfs4_put_open_state(state);
        nfs4_put_state_owner(sp);
        return status;
}

static struct inode *
nfs4_atomic_open(struct inode *dir, struct nfs_open_context *ctx,
                int open_flags, struct iattr *attr, int *opened)
{
        struct nfs4_state *state;
        struct nfs4_label l = {0, 0, 0, NULL}, *label = NULL;

        label = nfs4_label_init_security(dir, ctx->dentry, attr, &l);

        /* Protect against concurrent sillydeletes */
        state = nfs4_do_open(dir, ctx, open_flags, attr, label, opened);

        nfs4_label_release_security(label);

        if (IS_ERR(state))
                return ERR_CAST(state);
        return state->inode;
}

static void nfs4_close_context(struct nfs_open_context *ctx, int is_sync)
{
        if (ctx->state == NULL)
                return;
        if (is_sync)
                nfs4_close_sync(ctx->state, ctx->mode);
        else
                nfs4_close_state(ctx->state, ctx->mode);
}

#define FATTR4_WORD1_NFS40_MASK (2*FATTR4_WORD1_MOUNTED_ON_FILEID - 1UL)
#define FATTR4_WORD2_NFS41_MASK (2*FATTR4_WORD2_SUPPATTR_EXCLCREAT - 1UL)
#define FATTR4_WORD2_NFS42_MASK (2*FATTR4_WORD2_MODE_UMASK - 1UL)

static int _nfs4_server_capabilities(struct nfs_server *server, struct nfs_fh *fhandle)
{
        u32 bitmask[3] = {}, minorversion = server->nfs_client->cl_minorversion;
        struct nfs4_server_caps_arg args = {
                .fhandle = fhandle,
                .bitmask = bitmask,
        };
        struct nfs4_server_caps_res res = {};
        struct rpc_message msg = {
                .rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_SERVER_CAPS],
                .rpc_argp = &args,
                .rpc_resp = &res,
        };
        int status;
        int i;

        bitmask[0] = FATTR4_WORD0_SUPPORTED_ATTRS |
                     FATTR4_WORD0_FH_EXPIRE_TYPE |
                     FATTR4_WORD0_LINK_SUPPORT |
                     FATTR4_WORD0_SYMLINK_SUPPORT |
                     FATTR4_WORD0_ACLSUPPORT;
        if (minorversion)
                bitmask[2] = FATTR4_WORD2_SUPPATTR_EXCLCREAT;

        status = nfs4_call_sync(server->client, server, &msg, &args.seq_args, &res.seq_res, 0);
        if (status == 0) {
                /* Sanity check the server answers */
                switch (minorversion) {
                case 0:
                        res.attr_bitmask[1] &= FATTR4_WORD1_NFS40_MASK;
                        res.attr_bitmask[2] = 0;
                        break;
                case 1:
                        res.attr_bitmask[2] &= FATTR4_WORD2_NFS41_MASK;
                        break;
                case 2:
                        res.attr_bitmask[2] &= FATTR4_WORD2_NFS42_MASK;
                }
                memcpy(server->attr_bitmask, res.attr_bitmask, sizeof(server->attr_bitmask));
                server->caps &= ~(NFS_CAP_ACLS|NFS_CAP_HARDLINKS|
                                NFS_CAP_SYMLINKS|NFS_CAP_FILEID|
                                NFS_CAP_MODE|NFS_CAP_NLINK|NFS_CAP_OWNER|
                                NFS_CAP_OWNER_GROUP|NFS_CAP_ATIME|
                                NFS_CAP_CTIME|NFS_CAP_MTIME|
                                NFS_CAP_SECURITY_LABEL);
                if (res.attr_bitmask[0] & FATTR4_WORD0_ACL &&
                                res.acl_bitmask & ACL4_SUPPORT_ALLOW_ACL)
                        server->caps |= NFS_CAP_ACLS;
                if (res.has_links != 0)
                        server->caps |= NFS_CAP_HARDLINKS;
                if (res.has_symlinks != 0)
                        server->caps |= NFS_CAP_SYMLINKS;
                if (res.attr_bitmask[0] & FATTR4_WORD0_FILEID)
                        server->caps |= NFS_CAP_FILEID;
                if (res.attr_bitmask[1] & FATTR4_WORD1_MODE)
                        server->caps |= NFS_CAP_MODE;
                if (res.attr_bitmask[1] & FATTR4_WORD1_NUMLINKS)
                        server->caps |= NFS_CAP_NLINK;
                if (res.attr_bitmask[1] & FATTR4_WORD1_OWNER)
                        server->caps |= NFS_CAP_OWNER;
                if (res.attr_bitmask[1] & FATTR4_WORD1_OWNER_GROUP)
                        server->caps |= NFS_CAP_OWNER_GROUP;
                if (res.attr_bitmask[1] & FATTR4_WORD1_TIME_ACCESS)
                        server->caps |= NFS_CAP_ATIME;
                if (res.attr_bitmask[1] & FATTR4_WORD1_TIME_METADATA)
                        server->caps |= NFS_CAP_CTIME;
                if (res.attr_bitmask[1] & FATTR4_WORD1_TIME_MODIFY)
                        server->caps |= NFS_CAP_MTIME;
#ifdef CONFIG_NFS_V4_SECURITY_LABEL
                if (res.attr_bitmask[2] & FATTR4_WORD2_SECURITY_LABEL)
                        server->caps |= NFS_CAP_SECURITY_LABEL;
#endif
                memcpy(server->attr_bitmask_nl, res.attr_bitmask,
                                sizeof(server->attr_bitmask));
                server->attr_bitmask_nl[2] &= ~FATTR4_WORD2_SECURITY_LABEL;

                memcpy(server->cache_consistency_bitmask, res.attr_bitmask, sizeof(server->cache_consistency_bitmask));
                server->cache_consistency_bitmask[0] &= FATTR4_WORD0_CHANGE|FATTR4_WORD0_SIZE;
                server->cache_consistency_bitmask[1] &= FATTR4_WORD1_TIME_METADATA|FATTR4_WORD1_TIME_MODIFY;
                server->cache_consistency_bitmask[2] = 0;

                /* Avoid a regression due to buggy server */
                for (i = 0; i < ARRAY_SIZE(res.exclcreat_bitmask); i++)
                        res.exclcreat_bitmask[i] &= res.attr_bitmask[i];
                memcpy(server->exclcreat_bitmask, res.exclcreat_bitmask,
                        sizeof(server->exclcreat_bitmask));

                server->acl_bitmask = res.acl_bitmask;
                server->fh_expire_type = res.fh_expire_type;
        }

        return status;
}

int nfs4_server_capabilities(struct nfs_server *server, struct nfs_fh *fhandle)
{
        struct nfs4_exception exception = { };
        int err;
        do {
                err = nfs4_handle_exception(server,
                                _nfs4_server_capabilities(server, fhandle),
                                &exception);
        } while (exception.retry);
        return err;
}

static int _nfs4_lookup_root(struct nfs_server *server, struct nfs_fh *fhandle,
                struct nfs_fsinfo *info)
{
        u32 bitmask[3];
        struct nfs4_lookup_root_arg args = {
                .bitmask = bitmask,
        };
        struct nfs4_lookup_res res = {
                .server = server,
                .fattr = info->fattr,
                .fh = fhandle,
        };
        struct rpc_message msg = {
                .rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_LOOKUP_ROOT],
                .rpc_argp = &args,
                .rpc_resp = &res,
        };

        bitmask[0] = nfs4_fattr_bitmap[0];
        bitmask[1] = nfs4_fattr_bitmap[1];
        /*
         * Process the label in the upcoming getfattr
         */
        bitmask[2] = nfs4_fattr_bitmap[2] & ~FATTR4_WORD2_SECURITY_LABEL;

        nfs_fattr_init(info->fattr);
        return nfs4_call_sync(server->client, server, &msg, &args.seq_args, &res.seq_res, 0);
}

static int nfs4_lookup_root(struct nfs_server *server, struct nfs_fh *fhandle,
                struct nfs_fsinfo *info)
{
        struct nfs4_exception exception = { };
        int err;
        do {
                err = _nfs4_lookup_root(server, fhandle, info);
                trace_nfs4_lookup_root(server, fhandle, info->fattr, err);
                switch (err) {
                case 0:
                case -NFS4ERR_WRONGSEC:
                        goto out;
                default:
                        err = nfs4_handle_exception(server, err, &exception);
                }
        } while (exception.retry);
out:
        return err;
}

static int nfs4_lookup_root_sec(struct nfs_server *server, struct nfs_fh *fhandle,
                                struct nfs_fsinfo *info, rpc_authflavor_t flavor)
{
        struct rpc_auth_create_args auth_args = {
                .pseudoflavor = flavor,
        };
        struct rpc_auth *auth;

        auth = rpcauth_create(&auth_args, server->client);
        if (IS_ERR(auth))
                return -EACCES;
        return nfs4_lookup_root(server, fhandle, info);
}

/*
 * Retry pseudoroot lookup with various security flavors.  We do this when:
 *
 *   NFSv4.0: the PUTROOTFH operation returns NFS4ERR_WRONGSEC
 *   NFSv4.1: the server does not support the SECINFO_NO_NAME operation
 *
 * Returns zero on success, or a negative NFS4ERR value, or a
 * negative errno value.
 */
static int nfs4_find_root_sec(struct nfs_server *server, struct nfs_fh *fhandle,
                              struct nfs_fsinfo *info)
{
        /* Per 3530bis 15.33.5 */
        static const rpc_authflavor_t flav_array[] = {
                RPC_AUTH_GSS_KRB5P,
                RPC_AUTH_GSS_KRB5I,
                RPC_AUTH_GSS_KRB5,
                RPC_AUTH_UNIX,                  /* courtesy */
                RPC_AUTH_NULL,
        };
        int status = -EPERM;
        size_t i;

        if (server->auth_info.flavor_len > 0) {
                /* try each flavor specified by user */
                for (i = 0; i < server->auth_info.flavor_len; i++) {
                        status = nfs4_lookup_root_sec(server, fhandle, info,
                                                server->auth_info.flavors[i]);
                        if (status == -NFS4ERR_WRONGSEC || status == -EACCES)
                                continue;
                        break;
                }
        } else {
                /* no flavors specified by user, try default list */
                for (i = 0; i < ARRAY_SIZE(flav_array); i++) {
                        status = nfs4_lookup_root_sec(server, fhandle, info,
                                                      flav_array[i]);
                        if (status == -NFS4ERR_WRONGSEC || status == -EACCES)
                                continue;
                        break;
                }
        }

        /*
         * -EACCESS could mean that the user doesn't have correct permissions
         * to access the mount.  It could also mean that we tried to mount
         * with a gss auth flavor, but rpc.gssd isn't running.  Either way,
         * existing mount programs don't handle -EACCES very well so it should
         * be mapped to -EPERM instead.
         */
        if (status == -EACCES)
                status = -EPERM;
        return status;
}

/**
 * nfs4_proc_get_rootfh - get file handle for server's pseudoroot
 * @server: initialized nfs_server handle
 * @fhandle: we fill in the pseudo-fs root file handle
 * @info: we fill in an FSINFO struct
 * @auth_probe: probe the auth flavours
 *
 * Returns zero on success, or a negative errno.
 */
int nfs4_proc_get_rootfh(struct nfs_server *server, struct nfs_fh *fhandle,
                         struct nfs_fsinfo *info,
                         bool auth_probe)
{
        int status = 0;

        if (!auth_probe)
                status = nfs4_lookup_root(server, fhandle, info);

        if (auth_probe || status == NFS4ERR_WRONGSEC)
                status = server->nfs_client->cl_mvops->find_root_sec(server,
                                fhandle, info);

        if (status == 0)
                status = nfs4_server_capabilities(server, fhandle);
        if (status == 0)
                status = nfs4_do_fsinfo(server, fhandle, info);

        return nfs4_map_errors(status);
}

static int nfs4_proc_get_root(struct nfs_server *server, struct nfs_fh *mntfh,
                              struct nfs_fsinfo *info)
{
        int error;
        struct nfs_fattr *fattr = info->fattr;
        struct nfs4_label *label = NULL;

        error = nfs4_server_capabilities(server, mntfh);
        if (error < 0) {
                dprintk("nfs4_get_root: getcaps error = %d\n", -error);
                return error;
        }

        label = nfs4_label_alloc(server, GFP_KERNEL);
        if (IS_ERR(label))
                return PTR_ERR(label);

        error = nfs4_proc_getattr(server, mntfh, fattr, label);
        if (error < 0) {
                dprintk("nfs4_get_root: getattr error = %d\n", -error);
                goto err_free_label;
        }

        if (fattr->valid & NFS_ATTR_FATTR_FSID &&
            !nfs_fsid_equal(&server->fsid, &fattr->fsid))
                memcpy(&server->fsid, &fattr->fsid, sizeof(server->fsid));

err_free_label:
        nfs4_label_free(label);

        return error;
}

/*
 * Get locations and (maybe) other attributes of a referral.
 * Note that we'll actually follow the referral later when
 * we detect fsid mismatch in inode revalidation
 */
static int nfs4_get_referral(struct rpc_clnt *client, struct inode *dir,
                             const struct qstr *name, struct nfs_fattr *fattr,
                             struct nfs_fh *fhandle)
{
        int status = -ENOMEM;
        struct page *page = NULL;
        struct nfs4_fs_locations *locations = NULL;

        page = alloc_page(GFP_KERNEL);
        if (page == NULL)
                goto out;
        locations = kmalloc(sizeof(struct nfs4_fs_locations), GFP_KERNEL);
        if (locations == NULL)
                goto out;

        status = nfs4_proc_fs_locations(client, dir, name, locations, page);
        if (status != 0)
                goto out;

        /*
         * If the fsid didn't change, this is a migration event, not a
         * referral.  Cause us to drop into the exception handler, which
         * will kick off migration recovery.
         */
        if (nfs_fsid_equal(&NFS_SERVER(dir)->fsid, &locations->fattr.fsid)) {
                dprintk("%s: server did not return a different fsid for"
                        " a referral at %s\n", __func__, name->name);
                status = -NFS4ERR_MOVED;
                goto out;
        }
        /* Fixup attributes for the nfs_lookup() call to nfs_fhget() */
        nfs_fixup_referral_attributes(&locations->fattr);

        /* replace the lookup nfs_fattr with the locations nfs_fattr */
        memcpy(fattr, &locations->fattr, sizeof(struct nfs_fattr));
        memset(fhandle, 0, sizeof(struct nfs_fh));
out:
        if (page)
                __free_page(page);
        kfree(locations);
        return status;
}

static int _nfs4_proc_getattr(struct nfs_server *server, struct nfs_fh *fhandle,
                                struct nfs_fattr *fattr, struct nfs4_label *label)
{
        struct nfs4_getattr_arg args = {
                .fh = fhandle,
                .bitmask = server->attr_bitmask,
        };
        struct nfs4_getattr_res res = {
                .fattr = fattr,
                .label = label,
                .server = server,
        };
        struct rpc_message msg = {
                .rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_GETATTR],
                .rpc_argp = &args,
                .rpc_resp = &res,
        };

        args.bitmask = nfs4_bitmask(server, label);

        nfs_fattr_init(fattr);
        return nfs4_call_sync(server->client, server, &msg, &args.seq_args, &res.seq_res, 0);
}

static int nfs4_proc_getattr(struct nfs_server *server, struct nfs_fh *fhandle,
                                struct nfs_fattr *fattr, struct nfs4_label *label)
{
        struct nfs4_exception exception = { };
        int err;
        do {
                err = _nfs4_proc_getattr(server, fhandle, fattr, label);
                trace_nfs4_getattr(server, fhandle, fattr, err);
                err = nfs4_handle_exception(server, err,
                                &exception);
        } while (exception.retry);
        return err;
}

/* 
 * The file is not closed if it is opened due to the a request to change
 * the size of the file. The open call will not be needed once the
 * VFS layer lookup-intents are implemented.
 *
 * Close is called when the inode is destroyed.
 * If we haven't opened the file for O_WRONLY, we
 * need to in the size_change case to obtain a stateid.
 *
 * Got race?
 * Because OPEN is always done by name in nfsv4, it is
 * possible that we opened a different file by the same
 * name.  We can recognize this race condition, but we
 * can't do anything about it besides returning an error.
 *
 * This will be fixed with VFS changes (lookup-intent).
 */
static int
nfs4_proc_setattr(struct dentry *dentry, struct nfs_fattr *fattr,
                  struct iattr *sattr)
{
        struct inode *inode = d_inode(dentry);
        struct rpc_cred *cred = NULL;
        struct nfs_open_context *ctx = NULL;
        struct nfs4_label *label = NULL;
        int status;

        if (pnfs_ld_layoutret_on_setattr(inode) &&
            sattr->ia_valid & ATTR_SIZE &&
            sattr->ia_size < i_size_read(inode))
                pnfs_commit_and_return_layout(inode);

        nfs_fattr_init(fattr);
        
        /* Deal with open(O_TRUNC) */
        if (sattr->ia_valid & ATTR_OPEN)
                sattr->ia_valid &= ~(ATTR_MTIME|ATTR_CTIME);

        /* Optimization: if the end result is no change, don't RPC */
        if ((sattr->ia_valid & ~(ATTR_FILE|ATTR_OPEN)) == 0)
                return 0;

        /* Search for an existing open(O_WRITE) file */
        if (sattr->ia_valid & ATTR_FILE) {

                ctx = nfs_file_open_context(sattr->ia_file);
                if (ctx)
                        cred = ctx->cred;
        }

        label = nfs4_label_alloc(NFS_SERVER(inode), GFP_KERNEL);
        if (IS_ERR(label))
                return PTR_ERR(label);

        status = nfs4_do_setattr(inode, cred, fattr, sattr, ctx, NULL, label);
        if (status == 0) {
                nfs_setattr_update_inode(inode, sattr, fattr);
                nfs_setsecurity(inode, fattr, label);
        }
        nfs4_label_free(label);
        return status;
}

static int _nfs4_proc_lookup(struct rpc_clnt *clnt, struct inode *dir,
                const struct qstr *name, struct nfs_fh *fhandle,
                struct nfs_fattr *fattr, struct nfs4_label *label)
{
        struct nfs_server *server = NFS_SERVER(dir);
        int                    status;
        struct nfs4_lookup_arg args = {
                .bitmask = server->attr_bitmask,
                .dir_fh = NFS_FH(dir),
                .name = name,
        };
        struct nfs4_lookup_res res = {
                .server = server,
                .fattr = fattr,
                .label = label,
                .fh = fhandle,
        };
        struct rpc_message msg = {
                .rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_LOOKUP],
                .rpc_argp = &args,
                .rpc_resp = &res,
        };

        args.bitmask = nfs4_bitmask(server, label);

        nfs_fattr_init(fattr);

        dprintk("NFS call  lookup %s\n", name->name);
        status = nfs4_call_sync(clnt, server, &msg, &args.seq_args, &res.seq_res, 0);
        dprintk("NFS reply lookup: %d\n", status);
        return status;
}

static void nfs_fixup_secinfo_attributes(struct nfs_fattr *fattr)
{
        fattr->valid |= NFS_ATTR_FATTR_TYPE | NFS_ATTR_FATTR_MODE |
                NFS_ATTR_FATTR_NLINK | NFS_ATTR_FATTR_MOUNTPOINT;
        fattr->mode = S_IFDIR | S_IRUGO | S_IXUGO;
        fattr->nlink = 2;
}

static int nfs4_proc_lookup_common(struct rpc_clnt **clnt, struct inode *dir,
                                   const struct qstr *name, struct nfs_fh *fhandle,
                                   struct nfs_fattr *fattr, struct nfs4_label *label)
{
        struct nfs4_exception exception = { };
        struct rpc_clnt *client = *clnt;
        int err;
        do {
                err = _nfs4_proc_lookup(client, dir, name, fhandle, fattr, label);
                trace_nfs4_lookup(dir, name, err);
                switch (err) {
                case -NFS4ERR_BADNAME:
                        err = -ENOENT;
                        goto out;
                case -NFS4ERR_MOVED:
                        err = nfs4_get_referral(client, dir, name, fattr, fhandle);
                        if (err == -NFS4ERR_MOVED)
                                err = nfs4_handle_exception(NFS_SERVER(dir), err, &exception);
                        goto out;
                case -NFS4ERR_WRONGSEC:
                        err = -EPERM;
                        if (client != *clnt)
                                goto out;
                        client = nfs4_negotiate_security(client, dir, name);
                        if (IS_ERR(client))
                                return PTR_ERR(client);

                        exception.retry = 1;
                        break;
                default:
                        err = nfs4_handle_exception(NFS_SERVER(dir), err, &exception);
                }
        } while (exception.retry);

out:
        if (err == 0)
                *clnt = client;
        else if (client != *clnt)
                rpc_shutdown_client(client);

        return err;
}

static int nfs4_proc_lookup(struct inode *dir, const struct qstr *name,
                            struct nfs_fh *fhandle, struct nfs_fattr *fattr,
                            struct nfs4_label *label)
{
        int status;
        struct rpc_clnt *client = NFS_CLIENT(dir);

        status = nfs4_proc_lookup_common(&client, dir, name, fhandle, fattr, label);
        if (client != NFS_CLIENT(dir)) {
                rpc_shutdown_client(client);
                nfs_fixup_secinfo_attributes(fattr);
        }
        return status;
}

struct rpc_clnt *
nfs4_proc_lookup_mountpoint(struct inode *dir, const struct qstr *name,
                            struct nfs_fh *fhandle, struct nfs_fattr *fattr)
{
        struct rpc_clnt *client = NFS_CLIENT(dir);
        int status;

        status = nfs4_proc_lookup_common(&client, dir, name, fhandle, fattr, NULL);
        if (status < 0)
                return ERR_PTR(status);
        return (client == NFS_CLIENT(dir)) ? rpc_clone_client(client) : client;
}

static int _nfs4_proc_lookupp(struct inode *inode,
                struct nfs_fh *fhandle, struct nfs_fattr *fattr,
                struct nfs4_label *label)
{
        struct rpc_clnt *clnt = NFS_CLIENT(inode);
        struct nfs_server *server = NFS_SERVER(inode);
        int                    status;
        struct nfs4_lookupp_arg args = {
                .bitmask = server->attr_bitmask,
                .fh = NFS_FH(inode),
        };
        struct nfs4_lookupp_res res = {
                .server = server,
                .fattr = fattr,
                .label = label,
                .fh = fhandle,
        };
        struct rpc_message msg = {
                .rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_LOOKUPP],
                .rpc_argp = &args,
                .rpc_resp = &res,
        };

        args.bitmask = nfs4_bitmask(server, label);

        nfs_fattr_init(fattr);

        dprintk("NFS call  lookupp ino=0x%lx\n", inode->i_ino);
        status = nfs4_call_sync(clnt, server, &msg, &args.seq_args,
                                &res.seq_res, 0);
        dprintk("NFS reply lookupp: %d\n", status);
        return status;
}

static int nfs4_proc_lookupp(struct inode *inode, struct nfs_fh *fhandle,
                             struct nfs_fattr *fattr, struct nfs4_label *label)
{
        struct nfs4_exception exception = { };
        int err;
        do {
                err = _nfs4_proc_lookupp(inode, fhandle, fattr, label);
                trace_nfs4_lookupp(inode, err);
                err = nfs4_handle_exception(NFS_SERVER(inode), err,
                                &exception);
        } while (exception.retry);
        return err;
}

static int _nfs4_proc_access(struct inode *inode, struct nfs_access_entry *entry)
{
        struct nfs_server *server = NFS_SERVER(inode);
        struct nfs4_accessargs args = {
                .fh = NFS_FH(inode),
                .bitmask = server->cache_consistency_bitmask,
        };
        struct nfs4_accessres res = {
                .server = server,
        };
        struct rpc_message msg = {
                .rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_ACCESS],
                .rpc_argp = &args,
                .rpc_resp = &res,
                .rpc_cred = entry->cred,
        };
        int mode = entry->mask;
        int status = 0;

        /*
         * Determine which access bits we want to ask for...
         */
        if (mode & MAY_READ)
                args.access |= NFS4_ACCESS_READ;
        if (S_ISDIR(inode->i_mode)) {
                if (mode & MAY_WRITE)
                        args.access |= NFS4_ACCESS_MODIFY | NFS4_ACCESS_EXTEND | NFS4_ACCESS_DELETE;
                if (mode & MAY_EXEC)
                        args.access |= NFS4_ACCESS_LOOKUP;
        } else {
                if (mode & MAY_WRITE)
                        args.access |= NFS4_ACCESS_MODIFY | NFS4_ACCESS_EXTEND;
                if (mode & MAY_EXEC)
                        args.access |= NFS4_ACCESS_EXECUTE;
        }

        res.fattr = nfs_alloc_fattr();
        if (res.fattr == NULL)
                return -ENOMEM;

        status = nfs4_call_sync(server->client, server, &msg, &args.seq_args, &res.seq_res, 0);
        if (!status) {
                nfs_access_set_mask(entry, res.access);
                nfs_refresh_inode(inode, res.fattr);
        }
        nfs_free_fattr(res.fattr);
        return status;
}

static int nfs4_proc_access(struct inode *inode, struct nfs_access_entry *entry)
{
        struct nfs4_exception exception = { };
        int err;
        do {
                err = _nfs4_proc_access(inode, entry);
                trace_nfs4_access(inode, err);
                err = nfs4_handle_exception(NFS_SERVER(inode), err,
                                &exception);
        } while (exception.retry);
        return err;
}

/*
 * TODO: For the time being, we don't try to get any attributes
 * along with any of the zero-copy operations READ, READDIR,
 * READLINK, WRITE.
 *
 * In the case of the first three, we want to put the GETATTR
 * after the read-type operation -- this is because it is hard
 * to predict the length of a GETATTR response in v4, and thus
 * align the READ data correctly.  This means that the GETATTR
 * may end up partially falling into the page cache, and we should
 * shift it into the 'tail' of the xdr_buf before processing.
 * To do this efficiently, we need to know the total length
 * of data received, which doesn't seem to be available outside
 * of the RPC layer.
 *
 * In the case of WRITE, we also want to put the GETATTR after
 * the operation -- in this case because we want to make sure
 * we get the post-operation mtime and size.
 *
 * Both of these changes to the XDR layer would in fact be quite
 * minor, but I decided to leave them for a subsequent patch.
 */
static int _nfs4_proc_readlink(struct inode *inode, struct page *page,
                unsigned int pgbase, unsigned int pglen)
{
        struct nfs4_readlink args = {
                .fh       = NFS_FH(inode),
                .pgbase   = pgbase,
                .pglen    = pglen,
                .pages    = &page,
        };
        struct nfs4_readlink_res res;
        struct rpc_message msg = {
                .rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_READLINK],
                .rpc_argp = &args,
                .rpc_resp = &res,
        };

        return nfs4_call_sync(NFS_SERVER(inode)->client, NFS_SERVER(inode), &msg, &args.seq_args, &res.seq_res, 0);
}

static int nfs4_proc_readlink(struct inode *inode, struct page *page,
                unsigned int pgbase, unsigned int pglen)
{
        struct nfs4_exception exception = { };
        int err;
        do {
                err = _nfs4_proc_readlink(inode, page, pgbase, pglen);
                trace_nfs4_readlink(inode, err);
                err = nfs4_handle_exception(NFS_SERVER(inode), err,
                                &exception);
        } while (exception.retry);
        return err;
}

/*
 * This is just for mknod.  open(O_CREAT) will always do ->open_context().
 */
static int
nfs4_proc_create(struct inode *dir, struct dentry *dentry, struct iattr *sattr,
                 int flags)
{
        struct nfs_server *server = NFS_SERVER(dir);
        struct nfs4_label l, *ilabel = NULL;
        struct nfs_open_context *ctx;
        struct nfs4_state *state;
        int status = 0;

        ctx = alloc_nfs_open_context(dentry, FMODE_READ, NULL);
        if (IS_ERR(ctx))
                return PTR_ERR(ctx);

        ilabel = nfs4_label_init_security(dir, dentry, sattr, &l);

        if (!(server->attr_bitmask[2] & FATTR4_WORD2_MODE_UMASK))
                sattr->ia_mode &= ~current_umask();
        state = nfs4_do_open(dir, ctx, flags, sattr, ilabel, NULL);
        if (IS_ERR(state)) {
                status = PTR_ERR(state);
                goto out;
        }
out:
        nfs4_label_release_security(ilabel);
        put_nfs_open_context(ctx);
        return status;
}

static int _nfs4_proc_remove(struct inode *dir, const struct qstr *name)
{
        struct nfs_server *server = NFS_SERVER(dir);
        struct nfs_removeargs args = {
                .fh = NFS_FH(dir),
                .name = *name,
        };
        struct nfs_removeres res = {
                .server = server,
        };
        struct rpc_message msg = {
                .rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_REMOVE],
                .rpc_argp = &args,
                .rpc_resp = &res,
        };
        unsigned long timestamp = jiffies;
        int status;

        status = nfs4_call_sync(server->client, server, &msg, &args.seq_args, &res.seq_res, 1);
        if (status == 0)
                update_changeattr(dir, &res.cinfo, timestamp);
        return status;
}

static int nfs4_proc_remove(struct inode *dir, const struct qstr *name)
{
        struct nfs4_exception exception = { };
        int err;
        do {
                err = _nfs4_proc_remove(dir, name);
                trace_nfs4_remove(dir, name, err);
                err = nfs4_handle_exception(NFS_SERVER(dir), err,
                                &exception);
        } while (exception.retry);
        return err;
}

static void nfs4_proc_unlink_setup(struct rpc_message *msg, struct inode *dir)
{
        struct nfs_server *server = NFS_SERVER(dir);
        struct nfs_removeargs *args = msg->rpc_argp;
        struct nfs_removeres *res = msg->rpc_resp;

        res->server = server;
        msg->rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_REMOVE];
        nfs4_init_sequence(&args->seq_args, &res->seq_res, 1);

        nfs_fattr_init(res->dir_attr);
}

static void nfs4_proc_unlink_rpc_prepare(struct rpc_task *task, struct nfs_unlinkdata *data)
{
        nfs4_setup_sequence(NFS_SB(data->dentry->d_sb)->nfs_client,
                        &data->args.seq_args,
                        &data->res.seq_res,
                        task);
}

static int nfs4_proc_unlink_done(struct rpc_task *task, struct inode *dir)
{
        struct nfs_unlinkdata *data = task->tk_calldata;
        struct nfs_removeres *res = &data->res;

        if (!nfs4_sequence_done(task, &res->seq_res))
                return 0;
        if (nfs4_async_handle_error(task, res->server, NULL,
                                    &data->timeout) == -EAGAIN)
                return 0;
        if (task->tk_status == 0)
                update_changeattr(dir, &res->cinfo, res->dir_attr->time_start);
        return 1;
}

static void nfs4_proc_rename_setup(struct rpc_message *msg, struct inode *dir)
{
        struct nfs_server *server = NFS_SERVER(dir);
        struct nfs_renameargs *arg = msg->rpc_argp;
        struct nfs_renameres *res = msg->rpc_resp;

        msg->rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_RENAME];
        res->server = server;
        nfs4_init_sequence(&arg->seq_args, &res->seq_res, 1);
}

static void nfs4_proc_rename_rpc_prepare(struct rpc_task *task, struct nfs_renamedata *data)
{
        nfs4_setup_sequence(NFS_SERVER(data->old_dir)->nfs_client,
                        &data->args.seq_args,
                        &data->res.seq_res,
                        task);
}

static int nfs4_proc_rename_done(struct rpc_task *task, struct inode *old_dir,
                                 struct inode *new_dir)
{
        struct nfs_renamedata *data = task->tk_calldata;
        struct nfs_renameres *res = &data->res;

        if (!nfs4_sequence_done(task, &res->seq_res))
                return 0;
        if (nfs4_async_handle_error(task, res->server, NULL, &data->timeout) == -EAGAIN)
                return 0;

        if (task->tk_status == 0) {
                update_changeattr(old_dir, &res->old_cinfo, res->old_fattr->time_start);
                if (new_dir != old_dir)
                        update_changeattr(new_dir, &res->new_cinfo, res->new_fattr->time_start);
        }
        return 1;
}

static int _nfs4_proc_link(struct inode *inode, struct inode *dir, const struct qstr *name)
{
        struct nfs_server *server = NFS_SERVER(inode);
        struct nfs4_link_arg arg = {
                .fh     = NFS_FH(inode),
                .dir_fh = NFS_FH(dir),
                .name   = name,
                .bitmask = server->attr_bitmask,
        };
        struct nfs4_link_res res = {
                .server = server,
                .label = NULL,
        };
        struct rpc_message msg = {
                .rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_LINK],
                .rpc_argp = &arg,
                .rpc_resp = &res,
        };
        int status = -ENOMEM;

        res.fattr = nfs_alloc_fattr();
        if (res.fattr == NULL)
                goto out;

        res.label = nfs4_label_alloc(server, GFP_KERNEL);
        if (IS_ERR(res.label)) {
                status = PTR_ERR(res.label);
                goto out;
        }
        arg.bitmask = nfs4_bitmask(server, res.label);

        status = nfs4_call_sync(server->client, server, &msg, &arg.seq_args, &res.seq_res, 1);
        if (!status) {
                update_changeattr(dir, &res.cinfo, res.fattr->time_start);
                status = nfs_post_op_update_inode(inode, res.fattr);
                if (!status)
                        nfs_setsecurity(inode, res.fattr, res.label);
        }


        nfs4_label_free(res.label);

out:
        nfs_free_fattr(res.fattr);
        return status;
}

static int nfs4_proc_link(struct inode *inode, struct inode *dir, const struct qstr *name)
{
        struct nfs4_exception exception = { };
        int err;
        do {
                err = nfs4_handle_exception(NFS_SERVER(inode),
                                _nfs4_proc_link(inode, dir, name),
                                &exception);
        } while (exception.retry);
        return err;
}

struct nfs4_createdata {
        struct rpc_message msg;
        struct nfs4_create_arg arg;
        struct nfs4_create_res res;
        struct nfs_fh fh;
        struct nfs_fattr fattr;
        struct nfs4_label *label;
};

static struct nfs4_createdata *nfs4_alloc_createdata(struct inode *dir,
                const struct qstr *name, struct iattr *sattr, u32 ftype)
{
        struct nfs4_createdata *data;

        data = kzalloc(sizeof(*data), GFP_KERNEL);
        if (data != NULL) {
                struct nfs_server *server = NFS_SERVER(dir);

                data->label = nfs4_label_alloc(server, GFP_KERNEL);
                if (IS_ERR(data->label))
                        goto out_free;

                data->msg.rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_CREATE];
                data->msg.rpc_argp = &data->arg;
                data->msg.rpc_resp = &data->res;
                data->arg.dir_fh = NFS_FH(dir);
                data->arg.server = server;
                data->arg.name = name;
                data->arg.attrs = sattr;
                data->arg.ftype = ftype;
                data->arg.bitmask = nfs4_bitmask(server, data->label);
                data->arg.umask = current_umask();
                data->res.server = server;
                data->res.fh = &data->fh;
                data->res.fattr = &data->fattr;
                data->res.label = data->label;
                nfs_fattr_init(data->res.fattr);
        }
        return data;
out_free:
        kfree(data);
        return NULL;
}

static int nfs4_do_create(struct inode *dir, struct dentry *dentry, struct nfs4_createdata *data)
{
        int status = nfs4_call_sync(NFS_SERVER(dir)->client, NFS_SERVER(dir), &data->msg,
                                    &data->arg.seq_args, &data->res.seq_res, 1);
        if (status == 0) {
                update_changeattr(dir, &data->res.dir_cinfo,
                                data->res.fattr->time_start);
                status = nfs_instantiate(dentry, data->res.fh, data->res.fattr, data->res.label);
        }
        return status;
}

static void nfs4_free_createdata(struct nfs4_createdata *data)
{
        nfs4_label_free(data->label);
        kfree(data);
}

static int _nfs4_proc_symlink(struct inode *dir, struct dentry *dentry,
                struct page *page, unsigned int len, struct iattr *sattr,
                struct nfs4_label *label)
{
        struct nfs4_createdata *data;
        int status = -ENAMETOOLONG;

        if (len > NFS4_MAXPATHLEN)
                goto out;

        status = -ENOMEM;
        data = nfs4_alloc_createdata(dir, &dentry->d_name, sattr, NF4LNK);
        if (data == NULL)
                goto out;

        data->msg.rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_SYMLINK];
        data->arg.u.symlink.pages = &page;
        data->arg.u.symlink.len = len;
        data->arg.label = label;
        
        status = nfs4_do_create(dir, dentry, data);

        nfs4_free_createdata(data);
out:
        return status;
}

static int nfs4_proc_symlink(struct inode *dir, struct dentry *dentry,
                struct page *page, unsigned int len, struct iattr *sattr)
{
        struct nfs4_exception exception = { };
        struct nfs4_label l, *label = NULL;
        int err;

        label = nfs4_label_init_security(dir, dentry, sattr, &l);

        do {
                err = _nfs4_proc_symlink(dir, dentry, page, len, sattr, label);
                trace_nfs4_symlink(dir, &dentry->d_name, err);
                err = nfs4_handle_exception(NFS_SERVER(dir), err,
                                &exception);
        } while (exception.retry);

        nfs4_label_release_security(label);
        return err;
}

static int _nfs4_proc_mkdir(struct inode *dir, struct dentry *dentry,
                struct iattr *sattr, struct nfs4_label *label)
{
        struct nfs4_createdata *data;
        int status = -ENOMEM;

        data = nfs4_alloc_createdata(dir, &dentry->d_name, sattr, NF4DIR);
        if (data == NULL)
                goto out;

        data->arg.label = label;
        status = nfs4_do_create(dir, dentry, data);

        nfs4_free_createdata(data);
out:
        return status;
}

static int nfs4_proc_mkdir(struct inode *dir, struct dentry *dentry,
                struct iattr *sattr)
{
        struct nfs_server *server = NFS_SERVER(dir);
        struct nfs4_exception exception = { };
        struct nfs4_label l, *label = NULL;
        int err;

        label = nfs4_label_init_security(dir, dentry, sattr, &l);

        if (!(server->attr_bitmask[2] & FATTR4_WORD2_MODE_UMASK))
                sattr->ia_mode &= ~current_umask();
        do {
                err = _nfs4_proc_mkdir(dir, dentry, sattr, label);
                trace_nfs4_mkdir(dir, &dentry->d_name, err);
                err = nfs4_handle_exception(NFS_SERVER(dir), err,
                                &exception);
        } while (exception.retry);
        nfs4_label_release_security(label);

        return err;
}

static int _nfs4_proc_readdir(struct dentry *dentry, struct rpc_cred *cred,
                u64 cookie, struct page **pages, unsigned int count, bool plus)
{
        struct inode            *dir = d_inode(dentry);
        struct nfs4_readdir_arg args = {
                .fh = NFS_FH(dir),
                .pages = pages,
                .pgbase = 0,
                .count = count,
                .bitmask = NFS_SERVER(d_inode(dentry))->attr_bitmask,
                .plus = plus,
        };
        struct nfs4_readdir_res res;
        struct rpc_message msg = {
                .rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_READDIR],
                .rpc_argp = &args,
                .rpc_resp = &res,
                .rpc_cred = cred,
        };
        int                     status;

        dprintk("%s: dentry = %pd2, cookie = %Lu\n", __func__,
                        dentry,
                        (unsigned long long)cookie);
        nfs4_setup_readdir(cookie, NFS_I(dir)->cookieverf, dentry, &args);
        res.pgbase = args.pgbase;
        status = nfs4_call_sync(NFS_SERVER(dir)->client, NFS_SERVER(dir), &msg, &args.seq_args, &res.seq_res, 0);
        if (status >= 0) {
                memcpy(NFS_I(dir)->cookieverf, res.verifier.data, NFS4_VERIFIER_SIZE);
                status += args.pgbase;
        }

        nfs_invalidate_atime(dir);

        dprintk("%s: returns %d\n", __func__, status);
        return status;
}

static int nfs4_proc_readdir(struct dentry *dentry, struct rpc_cred *cred,
                u64 cookie, struct page **pages, unsigned int count, bool plus)
{
        struct nfs4_exception exception = { };
        int err;
        do {
                err = _nfs4_proc_readdir(dentry, cred, cookie,
                                pages, count, plus);
                trace_nfs4_readdir(d_inode(dentry), err);
                err = nfs4_handle_exception(NFS_SERVER(d_inode(dentry)), err,
                                &exception);
        } while (exception.retry);
        return err;
}

static int _nfs4_proc_mknod(struct inode *dir, struct dentry *dentry,
                struct iattr *sattr, struct nfs4_label *label, dev_t rdev)
{
        struct nfs4_createdata *data;
        int mode = sattr->ia_mode;
        int status = -ENOMEM;

        data = nfs4_alloc_createdata(dir, &dentry->d_name, sattr, NF4SOCK);
        if (data == NULL)
                goto out;

        if (S_ISFIFO(mode))
                data->arg.ftype = NF4FIFO;
        else if (S_ISBLK(mode)) {
                data->arg.ftype = NF4BLK;
                data->arg.u.device.specdata1 = MAJOR(rdev);
                data->arg.u.device.specdata2 = MINOR(rdev);
        }
        else if (S_ISCHR(mode)) {
                data->arg.ftype = NF4CHR;
                data->arg.u.device.specdata1 = MAJOR(rdev);
                data->arg.u.device.specdata2 = MINOR(rdev);
        } else if (!S_ISSOCK(mode)) {
                status = -EINVAL;
                goto out_free;
        }

        data->arg.label = label;
        status = nfs4_do_create(dir, dentry, data);
out_free:
        nfs4_free_createdata(data);
out:
        return status;
}

static int nfs4_proc_mknod(struct inode *dir, struct dentry *dentry,
                struct iattr *sattr, dev_t rdev)
{
        struct nfs_server *server = NFS_SERVER(dir);
        struct nfs4_exception exception = { };
        struct nfs4_label l, *label = NULL;
        int err;

        label = nfs4_label_init_security(dir, dentry, sattr, &l);

        if (!(server->attr_bitmask[2] & FATTR4_WORD2_MODE_UMASK))
                sattr->ia_mode &= ~current_umask();
        do {
                err = _nfs4_proc_mknod(dir, dentry, sattr, label, rdev);
                trace_nfs4_mknod(dir, &dentry->d_name, err);
                err = nfs4_handle_exception(NFS_SERVER(dir), err,
                                &exception);
        } while (exception.retry);

        nfs4_label_release_security(label);

        return err;
}

static int _nfs4_proc_statfs(struct nfs_server *server, struct nfs_fh *fhandle,
                 struct nfs_fsstat *fsstat)
{
        struct nfs4_statfs_arg args = {
                .fh = fhandle,
                .bitmask = server->attr_bitmask,
        };
        struct nfs4_statfs_res res = {
                .fsstat = fsstat,
        };
        struct rpc_message msg = {
                .rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_STATFS],
                .rpc_argp = &args,
                .rpc_resp = &res,
        };

        nfs_fattr_init(fsstat->fattr);
        return  nfs4_call_sync(server->client, server, &msg, &args.seq_args, &res.seq_res, 0);
}

static int nfs4_proc_statfs(struct nfs_server *server, struct nfs_fh *fhandle, struct nfs_fsstat *fsstat)
{
        struct nfs4_exception exception = { };
        int err;
        do {
                err = nfs4_handle_exception(server,
                                _nfs4_proc_statfs(server, fhandle, fsstat),
                                &exception);
        } while (exception.retry);
        return err;
}

static int _nfs4_do_fsinfo(struct nfs_server *server, struct nfs_fh *fhandle,
                struct nfs_fsinfo *fsinfo)
{
        struct nfs4_fsinfo_arg args = {
                .fh = fhandle,
                .bitmask = server->attr_bitmask,
        };
        struct nfs4_fsinfo_res res = {
                .fsinfo = fsinfo,
        };
        struct rpc_message msg = {
                .rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_FSINFO],
                .rpc_argp = &args,
                .rpc_resp = &res,
        };

        return nfs4_call_sync(server->client, server, &msg, &args.seq_args, &res.seq_res, 0);
}

static int nfs4_do_fsinfo(struct nfs_server *server, struct nfs_fh *fhandle, struct nfs_fsinfo *fsinfo)
{
        struct nfs4_exception exception = { };
        unsigned long now = jiffies;
        int err;

        do {
                err = _nfs4_do_fsinfo(server, fhandle, fsinfo);
                trace_nfs4_fsinfo(server, fhandle, fsinfo->fattr, err);
                if (err == 0) {
                        nfs4_set_lease_period(server->nfs_client,
                                        fsinfo->lease_time * HZ,
                                        now);
                        break;
                }
                err = nfs4_handle_exception(server, err, &exception);
        } while (exception.retry);
        return err;
}

static int nfs4_proc_fsinfo(struct nfs_server *server, struct nfs_fh *fhandle, struct nfs_fsinfo *fsinfo)
{
        int error;

        nfs_fattr_init(fsinfo->fattr);
        error = nfs4_do_fsinfo(server, fhandle, fsinfo);
        if (error == 0) {
                /* block layout checks this! */
                server->pnfs_blksize = fsinfo->blksize;
                set_pnfs_layoutdriver(server, fhandle, fsinfo);
        }

        return error;
}

static int _nfs4_proc_pathconf(struct nfs_server *server, struct nfs_fh *fhandle,
                struct nfs_pathconf *pathconf)
{
        struct nfs4_pathconf_arg args = {
                .fh = fhandle,
                .bitmask = server->attr_bitmask,
        };
        struct nfs4_pathconf_res res = {
                .pathconf = pathconf,
        };
        struct rpc_message msg = {
                .rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_PATHCONF],
                .rpc_argp = &args,
                .rpc_resp = &res,
        };

        /* None of the pathconf attributes are mandatory to implement */
        if ((args.bitmask[0] & nfs4_pathconf_bitmap[0]) == 0) {
                memset(pathconf, 0, sizeof(*pathconf));
                return 0;
        }

        nfs_fattr_init(pathconf->fattr);
        return nfs4_call_sync(server->client, server, &msg, &args.seq_args, &res.seq_res, 0);
}

static int nfs4_proc_pathconf(struct nfs_server *server, struct nfs_fh *fhandle,
                struct nfs_pathconf *pathconf)
{
        struct nfs4_exception exception = { };
        int err;

        do {
                err = nfs4_handle_exception(server,
                                _nfs4_proc_pathconf(server, fhandle, pathconf),
                                &exception);
        } while (exception.retry);
        return err;
}

int nfs4_set_rw_stateid(nfs4_stateid *stateid,
                const struct nfs_open_context *ctx,
                const struct nfs_lock_context *l_ctx,
                fmode_t fmode)
{
        return nfs4_select_rw_stateid(ctx->state, fmode, l_ctx, stateid, NULL);
}
EXPORT_SYMBOL_GPL(nfs4_set_rw_stateid);

static bool nfs4_stateid_is_current(nfs4_stateid *stateid,
                const struct nfs_open_context *ctx,
                const struct nfs_lock_context *l_ctx,
                fmode_t fmode)
{
        nfs4_stateid current_stateid;

        /* If the current stateid represents a lost lock, then exit */
        if (nfs4_set_rw_stateid(&current_stateid, ctx, l_ctx, fmode) == -EIO)
                return true;
        return nfs4_stateid_match(stateid, &current_stateid);
}

static bool nfs4_error_stateid_expired(int err)
{
        switch (err) {
        case -NFS4ERR_DELEG_REVOKED:
        case -NFS4ERR_ADMIN_REVOKED:
        case -NFS4ERR_BAD_STATEID:
        case -NFS4ERR_STALE_STATEID:
        case -NFS4ERR_OLD_STATEID:
        case -NFS4ERR_OPENMODE:
        case -NFS4ERR_EXPIRED:
                return true;
        }
        return false;
}

static int nfs4_read_done_cb(struct rpc_task *task, struct nfs_pgio_header *hdr)
{
        struct nfs_server *server = NFS_SERVER(hdr->inode);

        trace_nfs4_read(hdr, task->tk_status);
        if (task->tk_status < 0) {
                struct nfs4_exception exception = {
                        .inode = hdr->inode,
                        .state = hdr->args.context->state,
                        .stateid = &hdr->args.stateid,
                };
                task->tk_status = nfs4_async_handle_exception(task,
                                server, task->tk_status, &exception);
                if (exception.retry) {
                        rpc_restart_call_prepare(task);
                        return -EAGAIN;
                }
        }

        if (task->tk_status > 0)
                renew_lease(server, hdr->timestamp);
        return 0;
}

static bool nfs4_read_stateid_changed(struct rpc_task *task,
                struct nfs_pgio_args *args)
{

        if (!nfs4_error_stateid_expired(task->tk_status) ||
                nfs4_stateid_is_current(&args->stateid,
                                args->context,
                                args->lock_context,
                                FMODE_READ))
                return false;
        rpc_restart_call_prepare(task);
        return true;
}

static int nfs4_read_done(struct rpc_task *task, struct nfs_pgio_header *hdr)
{

        dprintk("--> %s\n", __func__);

        if (!nfs4_sequence_done(task, &hdr->res.seq_res))
                return -EAGAIN;
        if (nfs4_read_stateid_changed(task, &hdr->args))
                return -EAGAIN;
        if (task->tk_status > 0)
                nfs_invalidate_atime(hdr->inode);
        return hdr->pgio_done_cb ? hdr->pgio_done_cb(task, hdr) :
                                    nfs4_read_done_cb(task, hdr);
}

static void nfs4_proc_read_setup(struct nfs_pgio_header *hdr,
                                 struct rpc_message *msg)
{
        hdr->timestamp   = jiffies;
        if (!hdr->pgio_done_cb)
                hdr->pgio_done_cb = nfs4_read_done_cb;
        msg->rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_READ];
        nfs4_init_sequence(&hdr->args.seq_args, &hdr->res.seq_res, 0);
}

static int nfs4_proc_pgio_rpc_prepare(struct rpc_task *task,
                                      struct nfs_pgio_header *hdr)
{
        if (nfs4_setup_sequence(NFS_SERVER(hdr->inode)->nfs_client,
                        &hdr->args.seq_args,
                        &hdr->res.seq_res,
                        task))
                return 0;
        if (nfs4_set_rw_stateid(&hdr->args.stateid, hdr->args.context,
                                hdr->args.lock_context,
                                hdr->rw_mode) == -EIO)
                return -EIO;
        if (unlikely(test_bit(NFS_CONTEXT_BAD, &hdr->args.context->flags)))
                return -EIO;
        return 0;
}

static int nfs4_write_done_cb(struct rpc_task *task,
                              struct nfs_pgio_header *hdr)
{
        struct inode *inode = hdr->inode;

        trace_nfs4_write(hdr, task->tk_status);
        if (task->tk_status < 0) {
                struct nfs4_exception exception = {
                        .inode = hdr->inode,
                        .state = hdr->args.context->state,
                        .stateid = &hdr->args.stateid,
                };
                task->tk_status = nfs4_async_handle_exception(task,
                                NFS_SERVER(inode), task->tk_status,
                                &exception);
                if (exception.retry) {
                        rpc_restart_call_prepare(task);
                        return -EAGAIN;
                }
        }
        if (task->tk_status >= 0) {
                renew_lease(NFS_SERVER(inode), hdr->timestamp);
                nfs_writeback_update_inode(hdr);
        }
        return 0;
}

static bool nfs4_write_stateid_changed(struct rpc_task *task,
                struct nfs_pgio_args *args)
{

        if (!nfs4_error_stateid_expired(task->tk_status) ||
                nfs4_stateid_is_current(&args->stateid,
                                args->context,
                                args->lock_context,
                                FMODE_WRITE))
                return false;
        rpc_restart_call_prepare(task);
        return true;
}

static int nfs4_write_done(struct rpc_task *task, struct nfs_pgio_header *hdr)
{
        if (!nfs4_sequence_done(task, &hdr->res.seq_res))
                return -EAGAIN;
        if (nfs4_write_stateid_changed(task, &hdr->args))
                return -EAGAIN;
        return hdr->pgio_done_cb ? hdr->pgio_done_cb(task, hdr) :
                nfs4_write_done_cb(task, hdr);
}

static
bool nfs4_write_need_cache_consistency_data(struct nfs_pgio_header *hdr)
{
        /* Don't request attributes for pNFS or O_DIRECT writes */
        if (hdr->ds_clp != NULL || hdr->dreq != NULL)
                return false;
        /* Otherwise, request attributes if and only if we don't hold
         * a delegation
         */
        return nfs4_have_delegation(hdr->inode, FMODE_READ) == 0;
}

static void nfs4_proc_write_setup(struct nfs_pgio_header *hdr,
                                  struct rpc_message *msg)
{
        struct nfs_server *server = NFS_SERVER(hdr->inode);

        if (!nfs4_write_need_cache_consistency_data(hdr)) {
                hdr->args.bitmask = NULL;
                hdr->res.fattr = NULL;
        } else
                hdr->args.bitmask = server->cache_consistency_bitmask;

        if (!hdr->pgio_done_cb)
                hdr->pgio_done_cb = nfs4_write_done_cb;
        hdr->res.server = server;
        hdr->timestamp   = jiffies;

        msg->rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_WRITE];
        nfs4_init_sequence(&hdr->args.seq_args, &hdr->res.seq_res, 1);
}

static void nfs4_proc_commit_rpc_prepare(struct rpc_task *task, struct nfs_commit_data *data)
{
        nfs4_setup_sequence(NFS_SERVER(data->inode)->nfs_client,
                        &data->args.seq_args,
                        &data->res.seq_res,
                        task);
}

static int nfs4_commit_done_cb(struct rpc_task *task, struct nfs_commit_data *data)
{
        struct inode *inode = data->inode;

        trace_nfs4_commit(data, task->tk_status);
        if (nfs4_async_handle_error(task, NFS_SERVER(inode),
                                    NULL, NULL) == -EAGAIN) {
                rpc_restart_call_prepare(task);
                return -EAGAIN;
        }
        return 0;
}

static int nfs4_commit_done(struct rpc_task *task, struct nfs_commit_data *data)
{
        if (!nfs4_sequence_done(task, &data->res.seq_res))
                return -EAGAIN;
        return data->commit_done_cb(task, data);
}

static void nfs4_proc_commit_setup(struct nfs_commit_data *data, struct rpc_message *msg)
{
        struct nfs_server *server = NFS_SERVER(data->inode);

        if (data->commit_done_cb == NULL)
                data->commit_done_cb = nfs4_commit_done_cb;
        data->res.server = server;
        msg->rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_COMMIT];
        nfs4_init_sequence(&data->args.seq_args, &data->res.seq_res, 1);
}

struct nfs4_renewdata {
        struct nfs_client       *client;
        unsigned long           timestamp;
};

/*
 * nfs4_proc_async_renew(): This is not one of the nfs_rpc_ops; it is a special
 * standalone procedure for queueing an asynchronous RENEW.
 */
static void nfs4_renew_release(void *calldata)
{
        struct nfs4_renewdata *data = calldata;
        struct nfs_client *clp = data->client;

        if (atomic_read(&clp->cl_count) > 1)
                nfs4_schedule_state_renewal(clp);
        nfs_put_client(clp);
        kfree(data);
}

static void nfs4_renew_done(struct rpc_task *task, void *calldata)
{
        struct nfs4_renewdata *data = calldata;
        struct nfs_client *clp = data->client;
        unsigned long timestamp = data->timestamp;

        trace_nfs4_renew_async(clp, task->tk_status);
        switch (task->tk_status) {
        case 0:
                break;
        case -NFS4ERR_LEASE_MOVED:
                nfs4_schedule_lease_moved_recovery(clp);
                break;
        default:
                /* Unless we're shutting down, schedule state recovery! */
                if (test_bit(NFS_CS_RENEWD, &clp->cl_res_state) == 0)
                        return;
                if (task->tk_status != NFS4ERR_CB_PATH_DOWN) {
                        nfs4_schedule_lease_recovery(clp);
                        return;
                }
                nfs4_schedule_path_down_recovery(clp);
        }
        do_renew_lease(clp, timestamp);
}

static const struct rpc_call_ops nfs4_renew_ops = {
        .rpc_call_done = nfs4_renew_done,
        .rpc_release = nfs4_renew_release,
};

static int nfs4_proc_async_renew(struct nfs_client *clp, struct rpc_cred *cred, unsigned renew_flags)
{
        struct rpc_message msg = {
                .rpc_proc       = &nfs4_procedures[NFSPROC4_CLNT_RENEW],
                .rpc_argp       = clp,
                .rpc_cred       = cred,
        };
        struct nfs4_renewdata *data;

        if (renew_flags == 0)
                return 0;
        if (!atomic_inc_not_zero(&clp->cl_count))
                return -EIO;
        data = kmalloc(sizeof(*data), GFP_NOFS);
        if (data == NULL) {
                nfs_put_client(clp);
                return -ENOMEM;
        }
        data->client = clp;
        data->timestamp = jiffies;
        return rpc_call_async(clp->cl_rpcclient, &msg, RPC_TASK_TIMEOUT,
                        &nfs4_renew_ops, data);
}

static int nfs4_proc_renew(struct nfs_client *clp, struct rpc_cred *cred)
{
        struct rpc_message msg = {
                .rpc_proc       = &nfs4_procedures[NFSPROC4_CLNT_RENEW],
                .rpc_argp       = clp,
                .rpc_cred       = cred,
        };
        unsigned long now = jiffies;
        int status;

        status = rpc_call_sync(clp->cl_rpcclient, &msg, RPC_TASK_TIMEOUT);
        if (status < 0)
                return status;
        do_renew_lease(clp, now);
        return 0;
}

static inline int nfs4_server_supports_acls(struct nfs_server *server)
{
        return server->caps & NFS_CAP_ACLS;
}

/* Assuming that XATTR_SIZE_MAX is a multiple of PAGE_SIZE, and that
 * it's OK to put sizeof(void) * (XATTR_SIZE_MAX/PAGE_SIZE) bytes on
 * the stack.
 */
#define NFS4ACL_MAXPAGES DIV_ROUND_UP(XATTR_SIZE_MAX, PAGE_SIZE)

static int buf_to_pages_noslab(const void *buf, size_t buflen,
                struct page **pages)
{
        struct page *newpage, **spages;
        int rc = 0;
        size_t len;
        spages = pages;

        do {
                len = min_t(size_t, PAGE_SIZE, buflen);
                newpage = alloc_page(GFP_KERNEL);

                if (newpage == NULL)
                        goto unwind;
                memcpy(page_address(newpage), buf, len);
                buf += len;
                buflen -= len;
                *pages++ = newpage;
                rc++;
        } while (buflen != 0);

        return rc;

unwind:
        for(; rc > 0; rc--)
                __free_page(spages[rc-1]);
        return -ENOMEM;
}

struct nfs4_cached_acl {
        int cached;
        size_t len;
        char data[0];
};

static void nfs4_set_cached_acl(struct inode *inode, struct nfs4_cached_acl *acl)
{
        struct nfs_inode *nfsi = NFS_I(inode);

        spin_lock(&inode->i_lock);
        kfree(nfsi->nfs4_acl);
        nfsi->nfs4_acl = acl;
        spin_unlock(&inode->i_lock);
}

static void nfs4_zap_acl_attr(struct inode *inode)
{
        nfs4_set_cached_acl(inode, NULL);
}

static inline ssize_t nfs4_read_cached_acl(struct inode *inode, char *buf, size_t buflen)
{
        struct nfs_inode *nfsi = NFS_I(inode);
        struct nfs4_cached_acl *acl;
        int ret = -ENOENT;

        spin_lock(&inode->i_lock);
        acl = nfsi->nfs4_acl;
        if (acl == NULL)
                goto out;
        if (buf == NULL) /* user is just asking for length */
                goto out_len;
        if (acl->cached == 0)
                goto out;
        ret = -ERANGE; /* see getxattr(2) man page */
        if (acl->len > buflen)
                goto out;
        memcpy(buf, acl->data, acl->len);
out_len:
        ret = acl->len;
out:
        spin_unlock(&inode->i_lock);
        return ret;
}

static void nfs4_write_cached_acl(struct inode *inode, struct page **pages, size_t pgbase, size_t acl_len)
{
        struct nfs4_cached_acl *acl;
        size_t buflen = sizeof(*acl) + acl_len;

        if (buflen <= PAGE_SIZE) {
                acl = kmalloc(buflen, GFP_KERNEL);
                if (acl == NULL)
                        goto out;
                acl->cached = 1;
                _copy_from_pages(acl->data, pages, pgbase, acl_len);
        } else {
                acl = kmalloc(sizeof(*acl), GFP_KERNEL);
                if (acl == NULL)
                        goto out;
                acl->cached = 0;
        }
        acl->len = acl_len;
out:
        nfs4_set_cached_acl(inode, acl);
}

/*
 * The getxattr API returns the required buffer length when called with a
 * NULL buf. The NFSv4 acl tool then calls getxattr again after allocating
 * the required buf.  On a NULL buf, we send a page of data to the server
 * guessing that the ACL request can be serviced by a page. If so, we cache
 * up to the page of ACL data, and the 2nd call to getxattr is serviced by
 * the cache. If not so, we throw away the page, and cache the required
 * length. The next getxattr call will then produce another round trip to
 * the server, this time with the input buf of the required size.
 */
static ssize_t __nfs4_get_acl_uncached(struct inode *inode, void *buf, size_t buflen)
{
        struct page *pages[NFS4ACL_MAXPAGES + 1] = {NULL, };
        struct nfs_getaclargs args = {
                .fh = NFS_FH(inode),
                .acl_pages = pages,
                .acl_len = buflen,
        };
        struct nfs_getaclres res = {
                .acl_len = buflen,
        };
        struct rpc_message msg = {
                .rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_GETACL],
                .rpc_argp = &args,
                .rpc_resp = &res,
        };
        unsigned int npages = DIV_ROUND_UP(buflen, PAGE_SIZE) + 1;
        int ret = -ENOMEM, i;

        if (npages > ARRAY_SIZE(pages))
                return -ERANGE;

        for (i = 0; i < npages; i++) {
                pages[i] = alloc_page(GFP_KERNEL);
                if (!pages[i])
                        goto out_free;
        }

        /* for decoding across pages */
        res.acl_scratch = alloc_page(GFP_KERNEL);
        if (!res.acl_scratch)
                goto out_free;

        args.acl_len = npages * PAGE_SIZE;

        dprintk("%s  buf %p buflen %zu npages %d args.acl_len %zu\n",
                __func__, buf, buflen, npages, args.acl_len);
        ret = nfs4_call_sync(NFS_SERVER(inode)->client, NFS_SERVER(inode),
                             &msg, &args.seq_args, &res.seq_res, 0);
        if (ret)
                goto out_free;

        /* Handle the case where the passed-in buffer is too short */
        if (res.acl_flags & NFS4_ACL_TRUNC) {
                /* Did the user only issue a request for the acl length? */
                if (buf == NULL)
                        goto out_ok;
                ret = -ERANGE;
                goto out_free;
        }
        nfs4_write_cached_acl(inode, pages, res.acl_data_offset, res.acl_len);
        if (buf) {
                if (res.acl_len > buflen) {
                        ret = -ERANGE;
                        goto out_free;
                }
                _copy_from_pages(buf, pages, res.acl_data_offset, res.acl_len);
        }
out_ok:
        ret = res.acl_len;
out_free:
        for (i = 0; i < npages; i++)
                if (pages[i])
                        __free_page(pages[i]);
        if (res.acl_scratch)
                __free_page(res.acl_scratch);
        return ret;
}

static ssize_t nfs4_get_acl_uncached(struct inode *inode, void *buf, size_t buflen)
{
        struct nfs4_exception exception = { };
        ssize_t ret;
        do {
                ret = __nfs4_get_acl_uncached(inode, buf, buflen);
                trace_nfs4_get_acl(inode, ret);
                if (ret >= 0)
                        break;
                ret = nfs4_handle_exception(NFS_SERVER(inode), ret, &exception);
        } while (exception.retry);
        return ret;
}

static ssize_t nfs4_proc_get_acl(struct inode *inode, void *buf, size_t buflen)
{
        struct nfs_server *server = NFS_SERVER(inode);
        int ret;

        if (!nfs4_server_supports_acls(server))
                return -EOPNOTSUPP;
        ret = nfs_revalidate_inode(server, inode);
        if (ret < 0)
                return ret;
        if (NFS_I(inode)->cache_validity & NFS_INO_INVALID_ACL)
                nfs_zap_acl_cache(inode);
        ret = nfs4_read_cached_acl(inode, buf, buflen);
        if (ret != -ENOENT)
                /* -ENOENT is returned if there is no ACL or if there is an ACL
                 * but no cached acl data, just the acl length */
                return ret;
        return nfs4_get_acl_uncached(inode, buf, buflen);
}

static int __nfs4_proc_set_acl(struct inode *inode, const void *buf, size_t buflen)
{
        struct nfs_server *server = NFS_SERVER(inode);
        struct page *pages[NFS4ACL_MAXPAGES];
        struct nfs_setaclargs arg = {
                .fh             = NFS_FH(inode),
                .acl_pages      = pages,
                .acl_len        = buflen,
        };
        struct nfs_setaclres res;
        struct rpc_message msg = {
                .rpc_proc       = &nfs4_procedures[NFSPROC4_CLNT_SETACL],
                .rpc_argp       = &arg,
                .rpc_resp       = &res,
        };
        unsigned int npages = DIV_ROUND_UP(buflen, PAGE_SIZE);
        int ret, i;

        if (!nfs4_server_supports_acls(server))
                return -EOPNOTSUPP;
        if (npages > ARRAY_SIZE(pages))
                return -ERANGE;
        i = buf_to_pages_noslab(buf, buflen, arg.acl_pages);
        if (i < 0)
                return i;
        nfs4_inode_return_delegation(inode);
        ret = nfs4_call_sync(server->client, server, &msg, &arg.seq_args, &res.seq_res, 1);

        /*
         * Free each page after tx, so the only ref left is
         * held by the network stack
         */
        for (; i > 0; i--)
                put_page(pages[i-1]);

        /*
         * Acl update can result in inode attribute update.
         * so mark the attribute cache invalid.
         */
        spin_lock(&inode->i_lock);
        NFS_I(inode)->cache_validity |= NFS_INO_INVALID_ATTR;
        spin_unlock(&inode->i_lock);
        nfs_access_zap_cache(inode);
        nfs_zap_acl_cache(inode);
        return ret;
}

static int nfs4_proc_set_acl(struct inode *inode, const void *buf, size_t buflen)
{
        struct nfs4_exception exception = { };
        int err;
        do {
                err = __nfs4_proc_set_acl(inode, buf, buflen);
                trace_nfs4_set_acl(inode, err);
                err = nfs4_handle_exception(NFS_SERVER(inode), err,
                                &exception);
        } while (exception.retry);
        return err;
}

#ifdef CONFIG_NFS_V4_SECURITY_LABEL
static int _nfs4_get_security_label(struct inode *inode, void *buf,
                                        size_t buflen)
{
        struct nfs_server *server = NFS_SERVER(inode);
        struct nfs_fattr fattr;
        struct nfs4_label label = {0, 0, buflen, buf};

        u32 bitmask[3] = { 0, 0, FATTR4_WORD2_SECURITY_LABEL };
        struct nfs4_getattr_arg arg = {
                .fh             = NFS_FH(inode),
                .bitmask        = bitmask,
        };
        struct nfs4_getattr_res res = {
                .fattr          = &fattr,
                .label          = &label,
                .server         = server,
        };
        struct rpc_message msg = {
                .rpc_proc       = &nfs4_procedures[NFSPROC4_CLNT_GETATTR],
                .rpc_argp       = &arg,
                .rpc_resp       = &res,
        };
        int ret;

        nfs_fattr_init(&fattr);

        ret = nfs4_call_sync(server->client, server, &msg, &arg.seq_args, &res.seq_res, 0);
        if (ret)
                return ret;
        if (!(fattr.valid & NFS_ATTR_FATTR_V4_SECURITY_LABEL))
                return -ENOENT;
        return 0;
}

static int nfs4_get_security_label(struct inode *inode, void *buf,
                                        size_t buflen)
{
        struct nfs4_exception exception = { };
        int err;

        if (!nfs_server_capable(inode, NFS_CAP_SECURITY_LABEL))
                return -EOPNOTSUPP;

        do {
                err = _nfs4_get_security_label(inode, buf, buflen);
                trace_nfs4_get_security_label(inode, err);
                err = nfs4_handle_exception(NFS_SERVER(inode), err,
                                &exception);
        } while (exception.retry);
        return err;
}

static int _nfs4_do_set_security_label(struct inode *inode,
                struct nfs4_label *ilabel,
                struct nfs_fattr *fattr,
                struct nfs4_label *olabel)
{

        struct iattr sattr = {0};
        struct nfs_server *server = NFS_SERVER(inode);
        const u32 bitmask[3] = { 0, 0, FATTR4_WORD2_SECURITY_LABEL };
        struct nfs_setattrargs arg = {
                .fh             = NFS_FH(inode),
                .iap            = &sattr,
                .server         = server,
                .bitmask        = bitmask,
                .label          = ilabel,
        };
        struct nfs_setattrres res = {
                .fattr          = fattr,
                .label          = olabel,
                .server         = server,
        };
        struct rpc_message msg = {
                .rpc_proc       = &nfs4_procedures[NFSPROC4_CLNT_SETATTR],
                .rpc_argp       = &arg,
                .rpc_resp       = &res,
        };
        int status;

        nfs4_stateid_copy(&arg.stateid, &zero_stateid);

        status = nfs4_call_sync(server->client, server, &msg, &arg.seq_args, &res.seq_res, 1);
        if (status)
                dprintk("%s failed: %d\n", __func__, status);

        return status;
}

static int nfs4_do_set_security_label(struct inode *inode,
                struct nfs4_label *ilabel,
                struct nfs_fattr *fattr,
                struct nfs4_label *olabel)
{
        struct nfs4_exception exception = { };
        int err;

        do {
                err = _nfs4_do_set_security_label(inode, ilabel,
                                fattr, olabel);
                trace_nfs4_set_security_label(inode, err);
                err = nfs4_handle_exception(NFS_SERVER(inode), err,
                                &exception);
        } while (exception.retry);
        return err;
}

static int
nfs4_set_security_label(struct inode *inode, const void *buf, size_t buflen)
{
        struct nfs4_label ilabel, *olabel = NULL;
        struct nfs_fattr fattr;
        struct rpc_cred *cred;
        int status;

        if (!nfs_server_capable(inode, NFS_CAP_SECURITY_LABEL))
                return -EOPNOTSUPP;

        nfs_fattr_init(&fattr);

        ilabel.pi = 0;
        ilabel.lfs = 0;
        ilabel.label = (char *)buf;
        ilabel.len = buflen;

        cred = rpc_lookup_cred();
        if (IS_ERR(cred))
                return PTR_ERR(cred);

        olabel = nfs4_label_alloc(NFS_SERVER(inode), GFP_KERNEL);
        if (IS_ERR(olabel)) {
                status = -PTR_ERR(olabel);
                goto out;
        }

        status = nfs4_do_set_security_label(inode, &ilabel, &fattr, olabel);
        if (status == 0)
                nfs_setsecurity(inode, &fattr, olabel);

        nfs4_label_free(olabel);
out:
        put_rpccred(cred);
        return status;
}
#endif  /* CONFIG_NFS_V4_SECURITY_LABEL */


static void nfs4_init_boot_verifier(const struct nfs_client *clp,
                                    nfs4_verifier *bootverf)
{
        __be32 verf[2];

        if (test_bit(NFS4CLNT_PURGE_STATE, &clp->cl_state)) {
                /* An impossible timestamp guarantees this value
                 * will never match a generated boot time. */
                verf[0] = cpu_to_be32(U32_MAX);
                verf[1] = cpu_to_be32(U32_MAX);
        } else {
                struct nfs_net *nn = net_generic(clp->cl_net, nfs_net_id);
                u64 ns = ktime_to_ns(nn->boot_time);

                verf[0] = cpu_to_be32(ns >> 32);
                verf[1] = cpu_to_be32(ns);
        }
        memcpy(bootverf->data, verf, sizeof(bootverf->data));
}

static int
nfs4_init_nonuniform_client_string(struct nfs_client *clp)
{
        size_t len;
        char *str;

        if (clp->cl_owner_id != NULL)
                return 0;

        rcu_read_lock();
        len = 14 + strlen(clp->cl_ipaddr) + 1 +
                strlen(rpc_peeraddr2str(clp->cl_rpcclient, RPC_DISPLAY_ADDR)) +
                1 +
                strlen(rpc_peeraddr2str(clp->cl_rpcclient, RPC_DISPLAY_PROTO)) +
                1;
        rcu_read_unlock();

        if (len > NFS4_OPAQUE_LIMIT + 1)
                return -EINVAL;

        /*
         * Since this string is allocated at mount time, and held until the
         * nfs_client is destroyed, we can use GFP_KERNEL here w/o worrying
         * about a memory-reclaim deadlock.
         */
        str = kmalloc(len, GFP_KERNEL);
        if (!str)
                return -ENOMEM;

        rcu_read_lock();
        scnprintf(str, len, "Linux NFSv4.0 %s/%s %s",
                        clp->cl_ipaddr,
                        rpc_peeraddr2str(clp->cl_rpcclient, RPC_DISPLAY_ADDR),
                        rpc_peeraddr2str(clp->cl_rpcclient, RPC_DISPLAY_PROTO));
        rcu_read_unlock();

        clp->cl_owner_id = str;
        return 0;
}

static int
nfs4_init_uniquifier_client_string(struct nfs_client *clp)
{
        size_t len;
        char *str;

        len = 10 + 10 + 1 + 10 + 1 +
                strlen(nfs4_client_id_uniquifier) + 1 +
                strlen(clp->cl_rpcclient->cl_nodename) + 1;

        if (len > NFS4_OPAQUE_LIMIT + 1)
                return -EINVAL;

        /*
         * Since this string is allocated at mount time, and held until the
         * nfs_client is destroyed, we can use GFP_KERNEL here w/o worrying
         * about a memory-reclaim deadlock.
         */
        str = kmalloc(len, GFP_KERNEL);
        if (!str)
                return -ENOMEM;

        scnprintf(str, len, "Linux NFSv%u.%u %s/%s",
                        clp->rpc_ops->version, clp->cl_minorversion,
                        nfs4_client_id_uniquifier,
                        clp->cl_rpcclient->cl_nodename);
        clp->cl_owner_id = str;
        return 0;
}

static int
nfs4_init_uniform_client_string(struct nfs_client *clp)
{
        size_t len;
        char *str;

        if (clp->cl_owner_id != NULL)
                return 0;

        if (nfs4_client_id_uniquifier[0] != '\0')
                return nfs4_init_uniquifier_client_string(clp);

        len = 10 + 10 + 1 + 10 + 1 +
                strlen(clp->cl_rpcclient->cl_nodename) + 1;

        if (len > NFS4_OPAQUE_LIMIT + 1)
                return -EINVAL;

        /*
         * Since this string is allocated at mount time, and held until the
         * nfs_client is destroyed, we can use GFP_KERNEL here w/o worrying
         * about a memory-reclaim deadlock.
         */
        str = kmalloc(len, GFP_KERNEL);
        if (!str)
                return -ENOMEM;

        scnprintf(str, len, "Linux NFSv%u.%u %s",
                        clp->rpc_ops->version, clp->cl_minorversion,
                        clp->cl_rpcclient->cl_nodename);
        clp->cl_owner_id = str;
        return 0;
}

/*
 * nfs4_callback_up_net() starts only "tcp" and "tcp6" callback
 * services.  Advertise one based on the address family of the
 * clientaddr.
 */
static unsigned int
nfs4_init_callback_netid(const struct nfs_client *clp, char *buf, size_t len)
{
        if (strchr(clp->cl_ipaddr, ':') != NULL)
                return scnprintf(buf, len, "tcp6");
        else
                return scnprintf(buf, len, "tcp");
}

static void nfs4_setclientid_done(struct rpc_task *task, void *calldata)
{
        struct nfs4_setclientid *sc = calldata;

        if (task->tk_status == 0)
                sc->sc_cred = get_rpccred(task->tk_rqstp->rq_cred);
}

static const struct rpc_call_ops nfs4_setclientid_ops = {
        .rpc_call_done = nfs4_setclientid_done,
};

/**
 * nfs4_proc_setclientid - Negotiate client ID
 * @clp: state data structure
 * @program: RPC program for NFSv4 callback service
 * @port: IP port number for NFS4 callback service
 * @cred: RPC credential to use for this call
 * @res: where to place the result
 *
 * Returns zero, a negative errno, or a negative NFS4ERR status code.
 */
int nfs4_proc_setclientid(struct nfs_client *clp, u32 program,
                unsigned short port, struct rpc_cred *cred,
                struct nfs4_setclientid_res *res)
{
        nfs4_verifier sc_verifier;
        struct nfs4_setclientid setclientid = {
                .sc_verifier = &sc_verifier,
                .sc_prog = program,
                .sc_clnt = clp,
        };
        struct rpc_message msg = {
                .rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_SETCLIENTID],
                .rpc_argp = &setclientid,
                .rpc_resp = res,
                .rpc_cred = cred,
        };
        struct rpc_task *task;
        struct rpc_task_setup task_setup_data = {
                .rpc_client = clp->cl_rpcclient,
                .rpc_message = &msg,
                .callback_ops = &nfs4_setclientid_ops,
                .callback_data = &setclientid,
                .flags = RPC_TASK_TIMEOUT,
        };
        int status;

        /* nfs_client_id4 */
        nfs4_init_boot_verifier(clp, &sc_verifier);

        if (test_bit(NFS_CS_MIGRATION, &clp->cl_flags))
                status = nfs4_init_uniform_client_string(clp);
        else
                status = nfs4_init_nonuniform_client_string(clp);

        if (status)
                goto out;

        /* cb_client4 */
        setclientid.sc_netid_len =
                                nfs4_init_callback_netid(clp,
                                                setclientid.sc_netid,
                                                sizeof(setclientid.sc_netid));
        setclientid.sc_uaddr_len = scnprintf(setclientid.sc_uaddr,
                                sizeof(setclientid.sc_uaddr), "%s.%u.%u",
                                clp->cl_ipaddr, port >> 8, port & 255);

        dprintk("NFS call  setclientid auth=%s, '%s'\n",
                clp->cl_rpcclient->cl_auth->au_ops->au_name,
                clp->cl_owner_id);
        task = rpc_run_task(&task_setup_data);
        if (IS_ERR(task)) {
                status = PTR_ERR(task);
                goto out;
        }
        status = task->tk_status;
        if (setclientid.sc_cred) {
                kfree(clp->cl_acceptor);
                clp->cl_acceptor = rpcauth_stringify_acceptor(setclientid.sc_cred);
                put_rpccred(setclientid.sc_cred);
        }
        rpc_put_task(task);
out:
        trace_nfs4_setclientid(clp, status);
        dprintk("NFS reply setclientid: %d\n", status);
        return status;
}

/**
 * nfs4_proc_setclientid_confirm - Confirm client ID
 * @clp: state data structure
 * @res: result of a previous SETCLIENTID
 * @cred: RPC credential to use for this call
 *
 * Returns zero, a negative errno, or a negative NFS4ERR status code.
 */
int nfs4_proc_setclientid_confirm(struct nfs_client *clp,
                struct nfs4_setclientid_res *arg,
                struct rpc_cred *cred)
{
        struct rpc_message msg = {
                .rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_SETCLIENTID_CONFIRM],
                .rpc_argp = arg,
                .rpc_cred = cred,
        };
        int status;

        dprintk("NFS call  setclientid_confirm auth=%s, (client ID %llx)\n",
                clp->cl_rpcclient->cl_auth->au_ops->au_name,
                clp->cl_clientid);
        status = rpc_call_sync(clp->cl_rpcclient, &msg, RPC_TASK_TIMEOUT);
        trace_nfs4_setclientid_confirm(clp, status);
        dprintk("NFS reply setclientid_confirm: %d\n", status);
        return status;
}

struct nfs4_delegreturndata {
        struct nfs4_delegreturnargs args;
        struct nfs4_delegreturnres res;
        struct nfs_fh fh;
        nfs4_stateid stateid;
        unsigned long timestamp;
        struct {
                struct nfs4_layoutreturn_args arg;
                struct nfs4_layoutreturn_res res;
                struct nfs4_xdr_opaque_data ld_private;
                u32 roc_barrier;
                bool roc;
        } lr;
        struct nfs_fattr fattr;
        int rpc_status;
        struct inode *inode;
};

static void nfs4_delegreturn_done(struct rpc_task *task, void *calldata)
{
        struct nfs4_delegreturndata *data = calldata;

        if (!nfs4_sequence_done(task, &data->res.seq_res))
                return;

        trace_nfs4_delegreturn_exit(&data->args, &data->res, task->tk_status);

        /* Handle Layoutreturn errors */
        if (data->args.lr_args && task->tk_status != 0) {
                switch(data->res.lr_ret) {
                default:
                        data->res.lr_ret = -NFS4ERR_NOMATCHING_LAYOUT;
                        break;
                case 0:
                        data->args.lr_args = NULL;
                        data->res.lr_res = NULL;
                        break;
                case -NFS4ERR_ADMIN_REVOKED:
                case -NFS4ERR_DELEG_REVOKED:
                case -NFS4ERR_EXPIRED:
                case -NFS4ERR_BAD_STATEID:
                case -NFS4ERR_OLD_STATEID:
                case -NFS4ERR_UNKNOWN_LAYOUTTYPE:
                case -NFS4ERR_WRONG_CRED:
                        data->args.lr_args = NULL;
                        data->res.lr_res = NULL;
                        data->res.lr_ret = 0;
                        rpc_restart_call_prepare(task);
                        return;
                }
        }

        switch (task->tk_status) {
        case 0:
                renew_lease(data->res.server, data->timestamp);
                break;
        case -NFS4ERR_ADMIN_REVOKED:
        case -NFS4ERR_DELEG_REVOKED:
        case -NFS4ERR_EXPIRED:
                nfs4_free_revoked_stateid(data->res.server,
                                data->args.stateid,
                                task->tk_msg.rpc_cred);
        case -NFS4ERR_BAD_STATEID:
        case -NFS4ERR_OLD_STATEID:
        case -NFS4ERR_STALE_STATEID:
                task->tk_status = 0;
                break;
        case -NFS4ERR_ACCESS:
                if (data->args.bitmask) {
                        data->args.bitmask = NULL;
                        data->res.fattr = NULL;
                        task->tk_status = 0;
                        rpc_restart_call_prepare(task);
                        return;
                }
        default:
                if (nfs4_async_handle_error(task, data->res.server,
                                            NULL, NULL) == -EAGAIN) {
                        rpc_restart_call_prepare(task);
                        return;
                }
        }
        data->rpc_status = task->tk_status;
}

static void nfs4_delegreturn_release(void *calldata)
{
        struct nfs4_delegreturndata *data = calldata;
        struct inode *inode = data->inode;

        if (inode) {
                if (data->lr.roc)
                        pnfs_roc_release(&data->lr.arg, &data->lr.res,
                                        data->res.lr_ret);
                nfs_post_op_update_inode_force_wcc(inode, &data->fattr);
                nfs_iput_and_deactive(inode);
        }
        kfree(calldata);
}

static void nfs4_delegreturn_prepare(struct rpc_task *task, void *data)
{
        struct nfs4_delegreturndata *d_data;

        d_data = (struct nfs4_delegreturndata *)data;

        if (!d_data->lr.roc && nfs4_wait_on_layoutreturn(d_data->inode, task)) {
                nfs4_sequence_done(task, &d_data->res.seq_res);
                return;
        }

        nfs4_setup_sequence(d_data->res.server->nfs_client,
                        &d_data->args.seq_args,
                        &d_data->res.seq_res,
                        task);
}

static const struct rpc_call_ops nfs4_delegreturn_ops = {
        .rpc_call_prepare = nfs4_delegreturn_prepare,
        .rpc_call_done = nfs4_delegreturn_done,
        .rpc_release = nfs4_delegreturn_release,
};

static int _nfs4_proc_delegreturn(struct inode *inode, struct rpc_cred *cred, const nfs4_stateid *stateid, int issync)
{
        struct nfs4_delegreturndata *data;
        struct nfs_server *server = NFS_SERVER(inode);
        struct rpc_task *task;
        struct rpc_message msg = {
                .rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_DELEGRETURN],
                .rpc_cred = cred,
        };
        struct rpc_task_setup task_setup_data = {
                .rpc_client = server->client,
                .rpc_message = &msg,
                .callback_ops = &nfs4_delegreturn_ops,
                .flags = RPC_TASK_ASYNC,
        };
        int status = 0;

        data = kzalloc(sizeof(*data), GFP_NOFS);
        if (data == NULL)
                return -ENOMEM;
        nfs4_init_sequence(&data->args.seq_args, &data->res.seq_res, 1);

        nfs4_state_protect(server->nfs_client,
                        NFS_SP4_MACH_CRED_CLEANUP,
                        &task_setup_data.rpc_client, &msg);

        data->args.fhandle = &data->fh;
        data->args.stateid = &data->stateid;
        data->args.bitmask = server->cache_consistency_bitmask;
        nfs_copy_fh(&data->fh, NFS_FH(inode));
        nfs4_stateid_copy(&data->stateid, stateid);
        data->res.fattr = &data->fattr;
        data->res.server = server;
        data->res.lr_ret = -NFS4ERR_NOMATCHING_LAYOUT;
        data->lr.arg.ld_private = &data->lr.ld_private;
        nfs_fattr_init(data->res.fattr);
        data->timestamp = jiffies;
        data->rpc_status = 0;
        data->lr.roc = pnfs_roc(inode, &data->lr.arg, &data->lr.res, cred);
        data->inode = nfs_igrab_and_active(inode);
        if (data->inode) {
                if (data->lr.roc) {
                        data->args.lr_args = &data->lr.arg;
                        data->res.lr_res = &data->lr.res;
                }
        } else if (data->lr.roc) {
                pnfs_roc_release(&data->lr.arg, &data->lr.res, 0);
                data->lr.roc = false;
        }

        task_setup_data.callback_data = data;
        msg.rpc_argp = &data->args;
        msg.rpc_resp = &data->res;
        task = rpc_run_task(&task_setup_data);
        if (IS_ERR(task))
                return PTR_ERR(task);
        if (!issync)
                goto out;
        status = rpc_wait_for_completion_task(task);
        if (status != 0)
                goto out;
        status = data->rpc_status;
out:
        rpc_put_task(task);
        return status;
}

int nfs4_proc_delegreturn(struct inode *inode, struct rpc_cred *cred, const nfs4_stateid *stateid, int issync)
{
        struct nfs_server *server = NFS_SERVER(inode);
        struct nfs4_exception exception = { };
        int err;
        do {
                err = _nfs4_proc_delegreturn(inode, cred, stateid, issync);
                trace_nfs4_delegreturn(inode, stateid, err);
                switch (err) {
                        case -NFS4ERR_STALE_STATEID:
                        case -NFS4ERR_EXPIRED:
                        case 0:
                                return 0;
                }
                err = nfs4_handle_exception(server, err, &exception);
        } while (exception.retry);
        return err;
}

static int _nfs4_proc_getlk(struct nfs4_state *state, int cmd, struct file_lock *request)
{
        struct inode *inode = state->inode;
        struct nfs_server *server = NFS_SERVER(inode);
        struct nfs_client *clp = server->nfs_client;
        struct nfs_lockt_args arg = {
                .fh = NFS_FH(inode),
                .fl = request,
        };
        struct nfs_lockt_res res = {
                .denied = request,
        };
        struct rpc_message msg = {
                .rpc_proc       = &nfs4_procedures[NFSPROC4_CLNT_LOCKT],
                .rpc_argp       = &arg,
                .rpc_resp       = &res,
                .rpc_cred       = state->owner->so_cred,
        };
        struct nfs4_lock_state *lsp;
        int status;

        arg.lock_owner.clientid = clp->cl_clientid;
        status = nfs4_set_lock_state(state, request);
        if (status != 0)
                goto out;
        lsp = request->fl_u.nfs4_fl.owner;
        arg.lock_owner.id = lsp->ls_seqid.owner_id;
        arg.lock_owner.s_dev = server->s_dev;
        status = nfs4_call_sync(server->client, server, &msg, &arg.seq_args, &res.seq_res, 1);
        switch (status) {
                case 0:
                        request->fl_type = F_UNLCK;
                        break;
                case -NFS4ERR_DENIED:
                        status = 0;
        }
        request->fl_ops->fl_release_private(request);
        request->fl_ops = NULL;
out:
        return status;
}

static int nfs4_proc_getlk(struct nfs4_state *state, int cmd, struct file_lock *request)
{
        struct nfs4_exception exception = { };
        int err;

        do {
                err = _nfs4_proc_getlk(state, cmd, request);
                trace_nfs4_get_lock(request, state, cmd, err);
                err = nfs4_handle_exception(NFS_SERVER(state->inode), err,
                                &exception);
        } while (exception.retry);
        return err;
}

struct nfs4_unlockdata {
        struct nfs_locku_args arg;
        struct nfs_locku_res res;
        struct nfs4_lock_state *lsp;
        struct nfs_open_context *ctx;
        struct nfs_lock_context *l_ctx;
        struct file_lock fl;
        struct nfs_server *server;
        unsigned long timestamp;
};

static struct nfs4_unlockdata *nfs4_alloc_unlockdata(struct file_lock *fl,
                struct nfs_open_context *ctx,
                struct nfs4_lock_state *lsp,
                struct nfs_seqid *seqid)
{
        struct nfs4_unlockdata *p;
        struct inode *inode = lsp->ls_state->inode;

        p = kzalloc(sizeof(*p), GFP_NOFS);
        if (p == NULL)
                return NULL;
        p->arg.fh = NFS_FH(inode);
        p->arg.fl = &p->fl;
        p->arg.seqid = seqid;
        p->res.seqid = seqid;
        p->lsp = lsp;
        atomic_inc(&lsp->ls_count);
        /* Ensure we don't close file until we're done freeing locks! */
        p->ctx = get_nfs_open_context(ctx);
        p->l_ctx = nfs_get_lock_context(ctx);
        memcpy(&p->fl, fl, sizeof(p->fl));
        p->server = NFS_SERVER(inode);
        return p;
}

static void nfs4_locku_release_calldata(void *data)
{
        struct nfs4_unlockdata *calldata = data;
        nfs_free_seqid(calldata->arg.seqid);
        nfs4_put_lock_state(calldata->lsp);
        nfs_put_lock_context(calldata->l_ctx);
        put_nfs_open_context(calldata->ctx);
        kfree(calldata);
}

static void nfs4_locku_done(struct rpc_task *task, void *data)
{
        struct nfs4_unlockdata *calldata = data;

        if (!nfs4_sequence_done(task, &calldata->res.seq_res))
                return;
        switch (task->tk_status) {
                case 0:
                        renew_lease(calldata->server, calldata->timestamp);
                        locks_lock_inode_wait(calldata->lsp->ls_state->inode, &calldata->fl);
                        if (nfs4_update_lock_stateid(calldata->lsp,
                                        &calldata->res.stateid))
                                break;
                case -NFS4ERR_ADMIN_REVOKED:
                case -NFS4ERR_EXPIRED:
                        nfs4_free_revoked_stateid(calldata->server,
                                        &calldata->arg.stateid,
                                        task->tk_msg.rpc_cred);
                case -NFS4ERR_BAD_STATEID:
                case -NFS4ERR_OLD_STATEID:
                case -NFS4ERR_STALE_STATEID:
                        if (!nfs4_stateid_match(&calldata->arg.stateid,
                                                &calldata->lsp->ls_stateid))
                                rpc_restart_call_prepare(task);
                        break;
                default:
                        if (nfs4_async_handle_error(task, calldata->server,
                                                    NULL, NULL) == -EAGAIN)
                                rpc_restart_call_prepare(task);
        }
        nfs_release_seqid(calldata->arg.seqid);
}

static void nfs4_locku_prepare(struct rpc_task *task, void *data)
{
        struct nfs4_unlockdata *calldata = data;

        if (test_bit(NFS_CONTEXT_UNLOCK, &calldata->l_ctx->open_context->flags) &&
                nfs_async_iocounter_wait(task, calldata->l_ctx))
                return;

        if (nfs_wait_on_sequence(calldata->arg.seqid, task) != 0)
                goto out_wait;
        nfs4_stateid_copy(&calldata->arg.stateid, &calldata->lsp->ls_stateid);
        if (test_bit(NFS_LOCK_INITIALIZED, &calldata->lsp->ls_flags) == 0) {
                /* Note: exit _without_ running nfs4_locku_done */
                goto out_no_action;
        }
        calldata->timestamp = jiffies;
        if (nfs4_setup_sequence(calldata->server->nfs_client,
                                &calldata->arg.seq_args,
                                &calldata->res.seq_res,
                                task) != 0)
                nfs_release_seqid(calldata->arg.seqid);
        return;
out_no_action:
        task->tk_action = NULL;
out_wait:
        nfs4_sequence_done(task, &calldata->res.seq_res);
}

static const struct rpc_call_ops nfs4_locku_ops = {
        .rpc_call_prepare = nfs4_locku_prepare,
        .rpc_call_done = nfs4_locku_done,
        .rpc_release = nfs4_locku_release_calldata,
};

static struct rpc_task *nfs4_do_unlck(struct file_lock *fl,
                struct nfs_open_context *ctx,
                struct nfs4_lock_state *lsp,
                struct nfs_seqid *seqid)
{
        struct nfs4_unlockdata *data;
        struct rpc_message msg = {
                .rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_LOCKU],
                .rpc_cred = ctx->cred,
        };
        struct rpc_task_setup task_setup_data = {
                .rpc_client = NFS_CLIENT(lsp->ls_state->inode),
                .rpc_message = &msg,
                .callback_ops = &nfs4_locku_ops,
                .workqueue = nfsiod_workqueue,
                .flags = RPC_TASK_ASYNC,
        };

        nfs4_state_protect(NFS_SERVER(lsp->ls_state->inode)->nfs_client,
                NFS_SP4_MACH_CRED_CLEANUP, &task_setup_data.rpc_client, &msg);

        /* Ensure this is an unlock - when canceling a lock, the
         * canceled lock is passed in, and it won't be an unlock.
         */
        fl->fl_type = F_UNLCK;
        if (fl->fl_flags & FL_CLOSE)
                set_bit(NFS_CONTEXT_UNLOCK, &ctx->flags);

        data = nfs4_alloc_unlockdata(fl, ctx, lsp, seqid);
        if (data == NULL) {
                nfs_free_seqid(seqid);
                return ERR_PTR(-ENOMEM);
        }

        nfs4_init_sequence(&data->arg.seq_args, &data->res.seq_res, 1);
        msg.rpc_argp = &data->arg;
        msg.rpc_resp = &data->res;
        task_setup_data.callback_data = data;
        return rpc_run_task(&task_setup_data);
}

static int nfs4_proc_unlck(struct nfs4_state *state, int cmd, struct file_lock *request)
{
        struct inode *inode = state->inode;
        struct nfs4_state_owner *sp = state->owner;
        struct nfs_inode *nfsi = NFS_I(inode);
        struct nfs_seqid *seqid;
        struct nfs4_lock_state *lsp;
        struct rpc_task *task;
        struct nfs_seqid *(*alloc_seqid)(struct nfs_seqid_counter *, gfp_t);
        int status = 0;
        unsigned char fl_flags = request->fl_flags;

        status = nfs4_set_lock_state(state, request);
        /* Unlock _before_ we do the RPC call */
        request->fl_flags |= FL_EXISTS;
        /* Exclude nfs_delegation_claim_locks() */
        mutex_lock(&sp->so_delegreturn_mutex);
        /* Exclude nfs4_reclaim_open_stateid() - note nesting! */
        down_read(&nfsi->rwsem);
        if (locks_lock_inode_wait(inode, request) == -ENOENT) {
                up_read(&nfsi->rwsem);
                mutex_unlock(&sp->so_delegreturn_mutex);
                goto out;
        }
        up_read(&nfsi->rwsem);
        mutex_unlock(&sp->so_delegreturn_mutex);
        if (status != 0)
                goto out;
        /* Is this a delegated lock? */
        lsp = request->fl_u.nfs4_fl.owner;
        if (test_bit(NFS_LOCK_INITIALIZED, &lsp->ls_flags) == 0)
                goto out;
        alloc_seqid = NFS_SERVER(inode)->nfs_client->cl_mvops->alloc_seqid;
        seqid = alloc_seqid(&lsp->ls_seqid, GFP_KERNEL);
        status = -ENOMEM;
        if (IS_ERR(seqid))
                goto out;
        task = nfs4_do_unlck(request, nfs_file_open_context(request->fl_file), lsp, seqid);
        status = PTR_ERR(task);
        if (IS_ERR(task))
                goto out;
        status = rpc_wait_for_completion_task(task);
        rpc_put_task(task);
out:
        request->fl_flags = fl_flags;
        trace_nfs4_unlock(request, state, F_SETLK, status);
        return status;
}

struct nfs4_lockdata {
        struct nfs_lock_args arg;
        struct nfs_lock_res res;
        struct nfs4_lock_state *lsp;
        struct nfs_open_context *ctx;
        struct file_lock fl;
        unsigned long timestamp;
        int rpc_status;
        int cancelled;
        struct nfs_server *server;
};

static struct nfs4_lockdata *nfs4_alloc_lockdata(struct file_lock *fl,
                struct nfs_open_context *ctx, struct nfs4_lock_state *lsp,
                gfp_t gfp_mask)
{
        struct nfs4_lockdata *p;
        struct inode *inode = lsp->ls_state->inode;
        struct nfs_server *server = NFS_SERVER(inode);
        struct nfs_seqid *(*alloc_seqid)(struct nfs_seqid_counter *, gfp_t);

        p = kzalloc(sizeof(*p), gfp_mask);
        if (p == NULL)
                return NULL;

        p->arg.fh = NFS_FH(inode);
        p->arg.fl = &p->fl;
        p->arg.open_seqid = nfs_alloc_seqid(&lsp->ls_state->owner->so_seqid, gfp_mask);
        if (IS_ERR(p->arg.open_seqid))
                goto out_free;
        alloc_seqid = server->nfs_client->cl_mvops->alloc_seqid;
        p->arg.lock_seqid = alloc_seqid(&lsp->ls_seqid, gfp_mask);
        if (IS_ERR(p->arg.lock_seqid))
                goto out_free_seqid;
        p->arg.lock_owner.clientid = server->nfs_client->cl_clientid;
        p->arg.lock_owner.id = lsp->ls_seqid.owner_id;
        p->arg.lock_owner.s_dev = server->s_dev;
        p->res.lock_seqid = p->arg.lock_seqid;
        p->lsp = lsp;
        p->server = server;
        atomic_inc(&lsp->ls_count);
        p->ctx = get_nfs_open_context(ctx);
        memcpy(&p->fl, fl, sizeof(p->fl));
        return p;
out_free_seqid:
        nfs_free_seqid(p->arg.open_seqid);
out_free:
        kfree(p);
        return NULL;
}

static void nfs4_lock_prepare(struct rpc_task *task, void *calldata)
{
        struct nfs4_lockdata *data = calldata;
        struct nfs4_state *state = data->lsp->ls_state;

        dprintk("%s: begin!\n", __func__);
        if (nfs_wait_on_sequence(data->arg.lock_seqid, task) != 0)
                goto out_wait;
        /* Do we need to do an open_to_lock_owner? */
        if (!test_bit(NFS_LOCK_INITIALIZED, &data->lsp->ls_flags)) {
                if (nfs_wait_on_sequence(data->arg.open_seqid, task) != 0) {
                        goto out_release_lock_seqid;
                }
                nfs4_stateid_copy(&data->arg.open_stateid,
                                &state->open_stateid);
                data->arg.new_lock_owner = 1;
                data->res.open_seqid = data->arg.open_seqid;
        } else {
                data->arg.new_lock_owner = 0;
                nfs4_stateid_copy(&data->arg.lock_stateid,
                                &data->lsp->ls_stateid);
        }
        if (!nfs4_valid_open_stateid(state)) {
                data->rpc_status = -EBADF;
                task->tk_action = NULL;
                goto out_release_open_seqid;
        }
        data->timestamp = jiffies;
        if (nfs4_setup_sequence(data->server->nfs_client,
                                &data->arg.seq_args,
                                &data->res.seq_res,
                                task) == 0)
                return;
out_release_open_seqid:
        nfs_release_seqid(data->arg.open_seqid);
out_release_lock_seqid:
        nfs_release_seqid(data->arg.lock_seqid);
out_wait:
        nfs4_sequence_done(task, &data->res.seq_res);
        dprintk("%s: done!, ret = %d\n", __func__, data->rpc_status);
}

static void nfs4_lock_done(struct rpc_task *task, void *calldata)
{
        struct nfs4_lockdata *data = calldata;
        struct nfs4_lock_state *lsp = data->lsp;

        dprintk("%s: begin!\n", __func__);

        if (!nfs4_sequence_done(task, &data->res.seq_res))
                return;

        data->rpc_status = task->tk_status;
        switch (task->tk_status) {
        case 0:
                renew_lease(NFS_SERVER(d_inode(data->ctx->dentry)),
                                data->timestamp);
                if (data->arg.new_lock) {
                        data->fl.fl_flags &= ~(FL_SLEEP | FL_ACCESS);
                        if (locks_lock_inode_wait(lsp->ls_state->inode, &data->fl) < 0) {
                                rpc_restart_call_prepare(task);
                                break;
                        }
                }
                if (data->arg.new_lock_owner != 0) {
                        nfs_confirm_seqid(&lsp->ls_seqid, 0);
                        nfs4_stateid_copy(&lsp->ls_stateid, &data->res.stateid);
                        set_bit(NFS_LOCK_INITIALIZED, &lsp->ls_flags);
                } else if (!nfs4_update_lock_stateid(lsp, &data->res.stateid))
                        rpc_restart_call_prepare(task);
                break;
        case -NFS4ERR_BAD_STATEID:
        case -NFS4ERR_OLD_STATEID:
        case -NFS4ERR_STALE_STATEID:
        case -NFS4ERR_EXPIRED:
                if (data->arg.new_lock_owner != 0) {
                        if (!nfs4_stateid_match(&data->arg.open_stateid,
                                                &lsp->ls_state->open_stateid))
                                rpc_restart_call_prepare(task);
                } else if (!nfs4_stateid_match(&data->arg.lock_stateid,
                                                &lsp->ls_stateid))
                                rpc_restart_call_prepare(task);
        }
        dprintk("%s: done, ret = %d!\n", __func__, data->rpc_status);
}

static void nfs4_lock_release(void *calldata)
{
        struct nfs4_lockdata *data = calldata;

        dprintk("%s: begin!\n", __func__);
        nfs_free_seqid(data->arg.open_seqid);
        if (data->cancelled) {
                struct rpc_task *task;
                task = nfs4_do_unlck(&data->fl, data->ctx, data->lsp,
                                data->arg.lock_seqid);
                if (!IS_ERR(task))
                        rpc_put_task_async(task);
                dprintk("%s: cancelling lock!\n", __func__);
        } else
                nfs_free_seqid(data->arg.lock_seqid);
        nfs4_put_lock_state(data->lsp);
        put_nfs_open_context(data->ctx);
        kfree(data);
        dprintk("%s: done!\n", __func__);
}

static const struct rpc_call_ops nfs4_lock_ops = {
        .rpc_call_prepare = nfs4_lock_prepare,
        .rpc_call_done = nfs4_lock_done,
        .rpc_release = nfs4_lock_release,
};

static void nfs4_handle_setlk_error(struct nfs_server *server, struct nfs4_lock_state *lsp, int new_lock_owner, int error)
{
        switch (error) {
        case -NFS4ERR_ADMIN_REVOKED:
        case -NFS4ERR_EXPIRED:
        case -NFS4ERR_BAD_STATEID:
                lsp->ls_seqid.flags &= ~NFS_SEQID_CONFIRMED;
                if (new_lock_owner != 0 ||
                   test_bit(NFS_LOCK_INITIALIZED, &lsp->ls_flags) != 0)
                        nfs4_schedule_stateid_recovery(server, lsp->ls_state);
                break;
        case -NFS4ERR_STALE_STATEID:
                lsp->ls_seqid.flags &= ~NFS_SEQID_CONFIRMED;
                nfs4_schedule_lease_recovery(server->nfs_client);
        };
}

static int _nfs4_do_setlk(struct nfs4_state *state, int cmd, struct file_lock *fl, int recovery_type)
{
        struct nfs4_lockdata *data;
        struct rpc_task *task;
        struct rpc_message msg = {
                .rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_LOCK],
                .rpc_cred = state->owner->so_cred,
        };
        struct rpc_task_setup task_setup_data = {
                .rpc_client = NFS_CLIENT(state->inode),
                .rpc_message = &msg,
                .callback_ops = &nfs4_lock_ops,
                .workqueue = nfsiod_workqueue,
                .flags = RPC_TASK_ASYNC,
        };
        int ret;

        dprintk("%s: begin!\n", __func__);
        data = nfs4_alloc_lockdata(fl, nfs_file_open_context(fl->fl_file),
                        fl->fl_u.nfs4_fl.owner,
                        recovery_type == NFS_LOCK_NEW ? GFP_KERNEL : GFP_NOFS);
        if (data == NULL)
                return -ENOMEM;
        if (IS_SETLKW(cmd))
                data->arg.block = 1;
        nfs4_init_sequence(&data->arg.seq_args, &data->res.seq_res, 1);
        msg.rpc_argp = &data->arg;
        msg.rpc_resp = &data->res;
        task_setup_data.callback_data = data;
        if (recovery_type > NFS_LOCK_NEW) {
                if (recovery_type == NFS_LOCK_RECLAIM)
                        data->arg.reclaim = NFS_LOCK_RECLAIM;
                nfs4_set_sequence_privileged(&data->arg.seq_args);
        } else
                data->arg.new_lock = 1;
        task = rpc_run_task(&task_setup_data);
        if (IS_ERR(task))
                return PTR_ERR(task);
        ret = rpc_wait_for_completion_task(task);
        if (ret == 0) {
                ret = data->rpc_status;
                if (ret)
                        nfs4_handle_setlk_error(data->server, data->lsp,
                                        data->arg.new_lock_owner, ret);
        } else
                data->cancelled = true;
        rpc_put_task(task);
        dprintk("%s: done, ret = %d!\n", __func__, ret);
        trace_nfs4_set_lock(fl, state, &data->res.stateid, cmd, ret);
        return ret;
}

static int nfs4_lock_reclaim(struct nfs4_state *state, struct file_lock *request)
{
        struct nfs_server *server = NFS_SERVER(state->inode);
        struct nfs4_exception exception = {
                .inode = state->inode,
        };
        int err;

        do {
                /* Cache the lock if possible... */
                if (test_bit(NFS_DELEGATED_STATE, &state->flags) != 0)
                        return 0;
                err = _nfs4_do_setlk(state, F_SETLK, request, NFS_LOCK_RECLAIM);
                if (err != -NFS4ERR_DELAY)
                        break;
                nfs4_handle_exception(server, err, &exception);
        } while (exception.retry);
        return err;
}

static int nfs4_lock_expired(struct nfs4_state *state, struct file_lock *request)
{
        struct nfs_server *server = NFS_SERVER(state->inode);
        struct nfs4_exception exception = {
                .inode = state->inode,
        };
        int err;

        err = nfs4_set_lock_state(state, request);
        if (err != 0)
                return err;
        if (!recover_lost_locks) {
                set_bit(NFS_LOCK_LOST, &request->fl_u.nfs4_fl.owner->ls_flags);
                return 0;
        }
        do {
                if (test_bit(NFS_DELEGATED_STATE, &state->flags) != 0)
                        return 0;
                err = _nfs4_do_setlk(state, F_SETLK, request, NFS_LOCK_EXPIRED);
                switch (err) {
                default:
                        goto out;
                case -NFS4ERR_GRACE:
                case -NFS4ERR_DELAY:
                        nfs4_handle_exception(server, err, &exception);
                        err = 0;
                }
        } while (exception.retry);
out:
        return err;
}

#if defined(CONFIG_NFS_V4_1)
static int nfs41_lock_expired(struct nfs4_state *state, struct file_lock *request)
{
        struct nfs4_lock_state *lsp;
        int status;

        status = nfs4_set_lock_state(state, request);
        if (status != 0)
                return status;
        lsp = request->fl_u.nfs4_fl.owner;
        if (test_bit(NFS_LOCK_INITIALIZED, &lsp->ls_flags) ||
            test_bit(NFS_LOCK_LOST, &lsp->ls_flags))
                return 0;
        return nfs4_lock_expired(state, request);
}
#endif

static int _nfs4_proc_setlk(struct nfs4_state *state, int cmd, struct file_lock *request)
{
        struct nfs_inode *nfsi = NFS_I(state->inode);
        struct nfs4_state_owner *sp = state->owner;
        unsigned char fl_flags = request->fl_flags;
        int status;

        request->fl_flags |= FL_ACCESS;
        status = locks_lock_inode_wait(state->inode, request);
        if (status < 0)
                goto out;
        mutex_lock(&sp->so_delegreturn_mutex);
        down_read(&nfsi->rwsem);
        if (test_bit(NFS_DELEGATED_STATE, &state->flags)) {
                /* Yes: cache locks! */
                /* ...but avoid races with delegation recall... */
                request->fl_flags = fl_flags & ~FL_SLEEP;
                status = locks_lock_inode_wait(state->inode, request);
                up_read(&nfsi->rwsem);
                mutex_unlock(&sp->so_delegreturn_mutex);
                goto out;
        }
        up_read(&nfsi->rwsem);
        mutex_unlock(&sp->so_delegreturn_mutex);
        status = _nfs4_do_setlk(state, cmd, request, NFS_LOCK_NEW);
out:
        request->fl_flags = fl_flags;
        return status;
}

static int nfs4_proc_setlk(struct nfs4_state *state, int cmd, struct file_lock *request)
{
        struct nfs4_exception exception = {
                .state = state,
                .inode = state->inode,
        };
        int err;

        do {
                err = _nfs4_proc_setlk(state, cmd, request);
                if (err == -NFS4ERR_DENIED)
                        err = -EAGAIN;
                err = nfs4_handle_exception(NFS_SERVER(state->inode),
                                err, &exception);
        } while (exception.retry);
        return err;
}

#define NFS4_LOCK_MINTIMEOUT (1 * HZ)
#define NFS4_LOCK_MAXTIMEOUT (30 * HZ)

static int
nfs4_retry_setlk_simple(struct nfs4_state *state, int cmd,
                        struct file_lock *request)
{
        int             status = -ERESTARTSYS;
        unsigned long   timeout = NFS4_LOCK_MINTIMEOUT;

        while(!signalled()) {
                status = nfs4_proc_setlk(state, cmd, request);
                if ((status != -EAGAIN) || IS_SETLK(cmd))
                        break;
                freezable_schedule_timeout_interruptible(timeout);
                timeout *= 2;
                timeout = min_t(unsigned long, NFS4_LOCK_MAXTIMEOUT, timeout);
                status = -ERESTARTSYS;
        }
        return status;
}

#ifdef CONFIG_NFS_V4_1
struct nfs4_lock_waiter {
        struct task_struct      *task;
        struct inode            *inode;
        struct nfs_lowner       *owner;
        bool                    notified;
};

static int
nfs4_wake_lock_waiter(wait_queue_entry_t *wait, unsigned int mode, int flags, void *key)
{
        int ret;
        struct cb_notify_lock_args *cbnl = key;
        struct nfs4_lock_waiter *waiter = wait->private;
        struct nfs_lowner       *lowner = &cbnl->cbnl_owner,
                                *wowner = waiter->owner;

        /* Only wake if the callback was for the same owner */
        if (lowner->clientid != wowner->clientid ||
            lowner->id != wowner->id             ||
            lowner->s_dev != wowner->s_dev)
                return 0;

        /* Make sure it's for the right inode */
        if (nfs_compare_fh(NFS_FH(waiter->inode), &cbnl->cbnl_fh))
                return 0;

        waiter->notified = true;

        /* override "private" so we can use default_wake_function */
        wait->private = waiter->task;
        ret = autoremove_wake_function(wait, mode, flags, key);
        wait->private = waiter;
        return ret;
}

static int
nfs4_retry_setlk(struct nfs4_state *state, int cmd, struct file_lock *request)
{
        int status = -ERESTARTSYS;
        unsigned long flags;
        struct nfs4_lock_state *lsp = request->fl_u.nfs4_fl.owner;
        struct nfs_server *server = NFS_SERVER(state->inode);
        struct nfs_client *clp = server->nfs_client;
        wait_queue_head_t *q = &clp->cl_lock_waitq;
        struct nfs_lowner owner = { .clientid = clp->cl_clientid,
                                    .id = lsp->ls_seqid.owner_id,
                                    .s_dev = server->s_dev };
        struct nfs4_lock_waiter waiter = { .task  = current,
                                           .inode = state->inode,
                                           .owner = &owner,
                                           .notified = false };
        wait_queue_entry_t wait;

        /* Don't bother with waitqueue if we don't expect a callback */
        if (!test_bit(NFS_STATE_MAY_NOTIFY_LOCK, &state->flags))
                return nfs4_retry_setlk_simple(state, cmd, request);

        init_wait(&wait);
        wait.private = &waiter;
        wait.func = nfs4_wake_lock_waiter;
        add_wait_queue(q, &wait);

        while(!signalled()) {
                status = nfs4_proc_setlk(state, cmd, request);
                if ((status != -EAGAIN) || IS_SETLK(cmd))
                        break;

                status = -ERESTARTSYS;
                spin_lock_irqsave(&q->lock, flags);
                if (waiter.notified) {
                        spin_unlock_irqrestore(&q->lock, flags);
                        continue;
                }
                set_current_state(TASK_INTERRUPTIBLE);
                spin_unlock_irqrestore(&q->lock, flags);

                freezable_schedule_timeout(NFS4_LOCK_MAXTIMEOUT);
        }

        finish_wait(q, &wait);
        return status;
}
#else /* !CONFIG_NFS_V4_1 */
static inline int
nfs4_retry_setlk(struct nfs4_state *state, int cmd, struct file_lock *request)
{
        return nfs4_retry_setlk_simple(state, cmd, request);
}
#endif

static int
nfs4_proc_lock(struct file *filp, int cmd, struct file_lock *request)
{
        struct nfs_open_context *ctx;
        struct nfs4_state *state;
        int status;

        /* verify open state */
        ctx = nfs_file_open_context(filp);
        state = ctx->state;

        if (IS_GETLK(cmd)) {
                if (state != NULL)
                        return nfs4_proc_getlk(state, F_GETLK, request);
                return 0;
        }

        if (!(IS_SETLK(cmd) || IS_SETLKW(cmd)))
                return -EINVAL;

        if (request->fl_type == F_UNLCK) {
                if (state != NULL)
                        return nfs4_proc_unlck(state, cmd, request);
                return 0;
        }

        if (state == NULL)
                return -ENOLCK;

        if ((request->fl_flags & FL_POSIX) &&
            !test_bit(NFS_STATE_POSIX_LOCKS, &state->flags))
                return -ENOLCK;

        /*
         * Don't rely on the VFS having checked the file open mode,
         * since it won't do this for flock() locks.
         */
        switch (request->fl_type) {
        case F_RDLCK:
                if (!(filp->f_mode & FMODE_READ))
                        return -EBADF;
                break;
        case F_WRLCK:
                if (!(filp->f_mode & FMODE_WRITE))
                        return -EBADF;
        }

        status = nfs4_set_lock_state(state, request);
        if (status != 0)
                return status;

        return nfs4_retry_setlk(state, cmd, request);
}

int nfs4_lock_delegation_recall(struct file_lock *fl, struct nfs4_state *state, const nfs4_stateid *stateid)
{
        struct nfs_server *server = NFS_SERVER(state->inode);
        int err;

        err = nfs4_set_lock_state(state, fl);
        if (err != 0)
                return err;
        do {
                err = _nfs4_do_setlk(state, F_SETLK, fl, NFS_LOCK_NEW);
                if (err != -NFS4ERR_DELAY)
                        break;
                ssleep(1);
        } while (err == -NFS4ERR_DELAY);
        return nfs4_handle_delegation_recall_error(server, state, stateid, fl, err);
}

struct nfs_release_lockowner_data {
        struct nfs4_lock_state *lsp;
        struct nfs_server *server;
        struct nfs_release_lockowner_args args;
        struct nfs_release_lockowner_res res;
        unsigned long timestamp;
};

static void nfs4_release_lockowner_prepare(struct rpc_task *task, void *calldata)
{
        struct nfs_release_lockowner_data *data = calldata;
        struct nfs_server *server = data->server;
        nfs4_setup_sequence(server->nfs_client, &data->args.seq_args,
                           &data->res.seq_res, task);
        data->args.lock_owner.clientid = server->nfs_client->cl_clientid;
        data->timestamp = jiffies;
}

static void nfs4_release_lockowner_done(struct rpc_task *task, void *calldata)
{
        struct nfs_release_lockowner_data *data = calldata;
        struct nfs_server *server = data->server;

        nfs40_sequence_done(task, &data->res.seq_res);

        switch (task->tk_status) {
        case 0:
                renew_lease(server, data->timestamp);
                break;
        case -NFS4ERR_STALE_CLIENTID:
        case -NFS4ERR_EXPIRED:
                nfs4_schedule_lease_recovery(server->nfs_client);
                break;
        case -NFS4ERR_LEASE_MOVED:
        case -NFS4ERR_DELAY:
                if (nfs4_async_handle_error(task, server,
                                            NULL, NULL) == -EAGAIN)
                        rpc_restart_call_prepare(task);
        }
}

static void nfs4_release_lockowner_release(void *calldata)
{
        struct nfs_release_lockowner_data *data = calldata;
        nfs4_free_lock_state(data->server, data->lsp);
        kfree(calldata);
}

static const struct rpc_call_ops nfs4_release_lockowner_ops = {
        .rpc_call_prepare = nfs4_release_lockowner_prepare,
        .rpc_call_done = nfs4_release_lockowner_done,
        .rpc_release = nfs4_release_lockowner_release,
};

static void
nfs4_release_lockowner(struct nfs_server *server, struct nfs4_lock_state *lsp)
{
        struct nfs_release_lockowner_data *data;
        struct rpc_message msg = {
                .rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_RELEASE_LOCKOWNER],
        };

        if (server->nfs_client->cl_mvops->minor_version != 0)
                return;

        data = kmalloc(sizeof(*data), GFP_NOFS);
        if (!data)
                return;
        data->lsp = lsp;
        data->server = server;
        data->args.lock_owner.clientid = server->nfs_client->cl_clientid;
        data->args.lock_owner.id = lsp->ls_seqid.owner_id;
        data->args.lock_owner.s_dev = server->s_dev;

        msg.rpc_argp = &data->args;
        msg.rpc_resp = &data->res;
        nfs4_init_sequence(&data->args.seq_args, &data->res.seq_res, 0);
        rpc_call_async(server->client, &msg, 0, &nfs4_release_lockowner_ops, data);
}

#define XATTR_NAME_NFSV4_ACL "system.nfs4_acl"

static int nfs4_xattr_set_nfs4_acl(const struct xattr_handler *handler,
                                   struct dentry *unused, struct inode *inode,
                                   const char *key, const void *buf,
                                   size_t buflen, int flags)
{
        return nfs4_proc_set_acl(inode, buf, buflen);
}

static int nfs4_xattr_get_nfs4_acl(const struct xattr_handler *handler,
                                   struct dentry *unused, struct inode *inode,
                                   const char *key, void *buf, size_t buflen)
{
        return nfs4_proc_get_acl(inode, buf, buflen);
}

static bool nfs4_xattr_list_nfs4_acl(struct dentry *dentry)
{
        return nfs4_server_supports_acls(NFS_SERVER(d_inode(dentry)));
}

#ifdef CONFIG_NFS_V4_SECURITY_LABEL

static int nfs4_xattr_set_nfs4_label(const struct xattr_handler *handler,
                                     struct dentry *unused, struct inode *inode,
                                     const char *key, const void *buf,
                                     size_t buflen, int flags)
{
        if (security_ismaclabel(key))
                return nfs4_set_security_label(inode, buf, buflen);

        return -EOPNOTSUPP;
}

static int nfs4_xattr_get_nfs4_label(const struct xattr_handler *handler,
                                     struct dentry *unused, struct inode *inode,
                                     const char *key, void *buf, size_t buflen)
{
        if (security_ismaclabel(key))
                return nfs4_get_security_label(inode, buf, buflen);
        return -EOPNOTSUPP;
}

static ssize_t
nfs4_listxattr_nfs4_label(struct inode *inode, char *list, size_t list_len)
{
        int len = 0;

        if (nfs_server_capable(inode, NFS_CAP_SECURITY_LABEL)) {
                len = security_inode_listsecurity(inode, list, list_len);
                if (list_len && len > list_len)
                        return -ERANGE;
        }
        return len;
}

static const struct xattr_handler nfs4_xattr_nfs4_label_handler = {
        .prefix = XATTR_SECURITY_PREFIX,
        .get    = nfs4_xattr_get_nfs4_label,
        .set    = nfs4_xattr_set_nfs4_label,
};

#else

static ssize_t
nfs4_listxattr_nfs4_label(struct inode *inode, char *list, size_t list_len)
{
        return 0;
}

#endif

/*
 * nfs_fhget will use either the mounted_on_fileid or the fileid
 */
static void nfs_fixup_referral_attributes(struct nfs_fattr *fattr)
{
        if (!(((fattr->valid & NFS_ATTR_FATTR_MOUNTED_ON_FILEID) ||
               (fattr->valid & NFS_ATTR_FATTR_FILEID)) &&
              (fattr->valid & NFS_ATTR_FATTR_FSID) &&
              (fattr->valid & NFS_ATTR_FATTR_V4_LOCATIONS)))
                return;

        fattr->valid |= NFS_ATTR_FATTR_TYPE | NFS_ATTR_FATTR_MODE |
                NFS_ATTR_FATTR_NLINK | NFS_ATTR_FATTR_V4_REFERRAL;
        fattr->mode = S_IFDIR | S_IRUGO | S_IXUGO;
        fattr->nlink = 2;
}

static int _nfs4_proc_fs_locations(struct rpc_clnt *client, struct inode *dir,
                                   const struct qstr *name,
                                   struct nfs4_fs_locations *fs_locations,
                                   struct page *page)
{
        struct nfs_server *server = NFS_SERVER(dir);
        u32 bitmask[3];
        struct nfs4_fs_locations_arg args = {
                .dir_fh = NFS_FH(dir),
                .name = name,
                .page = page,
                .bitmask = bitmask,
        };
        struct nfs4_fs_locations_res res = {
                .fs_locations = fs_locations,
        };
        struct rpc_message msg = {
                .rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_FS_LOCATIONS],
                .rpc_argp = &args,
                .rpc_resp = &res,
        };
        int status;

        dprintk("%s: start\n", __func__);

        bitmask[0] = nfs4_fattr_bitmap[0] | FATTR4_WORD0_FS_LOCATIONS;
        bitmask[1] = nfs4_fattr_bitmap[1];

        /* Ask for the fileid of the absent filesystem if mounted_on_fileid
         * is not supported */
        if (NFS_SERVER(dir)->attr_bitmask[1] & FATTR4_WORD1_MOUNTED_ON_FILEID)
                bitmask[0] &= ~FATTR4_WORD0_FILEID;
        else
                bitmask[1] &= ~FATTR4_WORD1_MOUNTED_ON_FILEID;

        nfs_fattr_init(&fs_locations->fattr);
        fs_locations->server = server;
        fs_locations->nlocations = 0;
        status = nfs4_call_sync(client, server, &msg, &args.seq_args, &res.seq_res, 0);
        dprintk("%s: returned status = %d\n", __func__, status);
        return status;
}

int nfs4_proc_fs_locations(struct rpc_clnt *client, struct inode *dir,
                           const struct qstr *name,
                           struct nfs4_fs_locations *fs_locations,
                           struct page *page)
{
        struct nfs4_exception exception = { };
        int err;
        do {
                err = _nfs4_proc_fs_locations(client, dir, name,
                                fs_locations, page);
                trace_nfs4_get_fs_locations(dir, name, err);
                err = nfs4_handle_exception(NFS_SERVER(dir), err,
                                &exception);
        } while (exception.retry);
        return err;
}

/*
 * This operation also signals the server that this client is
 * performing migration recovery.  The server can stop returning
 * NFS4ERR_LEASE_MOVED to this client.  A RENEW operation is
 * appended to this compound to identify the client ID which is
 * performing recovery.
 */
static int _nfs40_proc_get_locations(struct inode *inode,
                                     struct nfs4_fs_locations *locations,
                                     struct page *page, struct rpc_cred *cred)
{
        struct nfs_server *server = NFS_SERVER(inode);
        struct rpc_clnt *clnt = server->client;
        u32 bitmask[2] = {
                [0] = FATTR4_WORD0_FSID | FATTR4_WORD0_FS_LOCATIONS,
        };
        struct nfs4_fs_locations_arg args = {
                .clientid       = server->nfs_client->cl_clientid,
                .fh             = NFS_FH(inode),
                .page           = page,
                .bitmask        = bitmask,
                .migration      = 1,            /* skip LOOKUP */
                .renew          = 1,            /* append RENEW */
        };
        struct nfs4_fs_locations_res res = {
                .fs_locations   = locations,
                .migration      = 1,
                .renew          = 1,
        };
        struct rpc_message msg = {
                .rpc_proc       = &nfs4_procedures[NFSPROC4_CLNT_FS_LOCATIONS],
                .rpc_argp       = &args,
                .rpc_resp       = &res,
                .rpc_cred       = cred,
        };
        unsigned long now = jiffies;
        int status;

        nfs_fattr_init(&locations->fattr);
        locations->server = server;
        locations->nlocations = 0;

        nfs4_init_sequence(&args.seq_args, &res.seq_res, 0);
        nfs4_set_sequence_privileged(&args.seq_args);
        status = nfs4_call_sync_sequence(clnt, server, &msg,
                                        &args.seq_args, &res.seq_res);
        if (status)
                return status;

        renew_lease(server, now);
        return 0;
}

#ifdef CONFIG_NFS_V4_1

/*
 * This operation also signals the server that this client is
 * performing migration recovery.  The server can stop asserting
 * SEQ4_STATUS_LEASE_MOVED for this client.  The client ID
 * performing this operation is identified in the SEQUENCE
 * operation in this compound.
 *
 * When the client supports GETATTR(fs_locations_info), it can
 * be plumbed in here.
 */
static int _nfs41_proc_get_locations(struct inode *inode,
                                     struct nfs4_fs_locations *locations,
                                     struct page *page, struct rpc_cred *cred)
{
        struct nfs_server *server = NFS_SERVER(inode);
        struct rpc_clnt *clnt = server->client;
        u32 bitmask[2] = {
                [0] = FATTR4_WORD0_FSID | FATTR4_WORD0_FS_LOCATIONS,
        };
        struct nfs4_fs_locations_arg args = {
                .fh             = NFS_FH(inode),
                .page           = page,
                .bitmask        = bitmask,
                .migration      = 1,            /* skip LOOKUP */
        };
        struct nfs4_fs_locations_res res = {
                .fs_locations   = locations,
                .migration      = 1,
        };
        struct rpc_message msg = {
                .rpc_proc       = &nfs4_procedures[NFSPROC4_CLNT_FS_LOCATIONS],
                .rpc_argp       = &args,
                .rpc_resp       = &res,
                .rpc_cred       = cred,
        };
        int status;

        nfs_fattr_init(&locations->fattr);
        locations->server = server;
        locations->nlocations = 0;

        nfs4_init_sequence(&args.seq_args, &res.seq_res, 0);
        nfs4_set_sequence_privileged(&args.seq_args);
        status = nfs4_call_sync_sequence(clnt, server, &msg,
                                        &args.seq_args, &res.seq_res);
        if (status == NFS4_OK &&
            res.seq_res.sr_status_flags & SEQ4_STATUS_LEASE_MOVED)
                status = -NFS4ERR_LEASE_MOVED;
        return status;
}

#endif  /* CONFIG_NFS_V4_1 */

/**
 * nfs4_proc_get_locations - discover locations for a migrated FSID
 * @inode: inode on FSID that is migrating
 * @locations: result of query
 * @page: buffer
 * @cred: credential to use for this operation
 *
 * Returns NFS4_OK on success, a negative NFS4ERR status code if the
 * operation failed, or a negative errno if a local error occurred.
 *
 * On success, "locations" is filled in, but if the server has
 * no locations information, NFS_ATTR_FATTR_V4_LOCATIONS is not
 * asserted.
 *
 * -NFS4ERR_LEASE_MOVED is returned if the server still has leases
 * from this client that require migration recovery.
 */
int nfs4_proc_get_locations(struct inode *inode,
                            struct nfs4_fs_locations *locations,
                            struct page *page, struct rpc_cred *cred)
{
        struct nfs_server *server = NFS_SERVER(inode);
        struct nfs_client *clp = server->nfs_client;
        const struct nfs4_mig_recovery_ops *ops =
                                        clp->cl_mvops->mig_recovery_ops;
        struct nfs4_exception exception = { };
        int status;

        dprintk("%s: FSID %llx:%llx on \"%s\"\n", __func__,
                (unsigned long long)server->fsid.major,
                (unsigned long long)server->fsid.minor,
                clp->cl_hostname);
        nfs_display_fhandle(NFS_FH(inode), __func__);

        do {
                status = ops->get_locations(inode, locations, page, cred);
                if (status != -NFS4ERR_DELAY)
                        break;
                nfs4_handle_exception(server, status, &exception);
        } while (exception.retry);
        return status;
}

/*
 * This operation also signals the server that this client is
 * performing "lease moved" recovery.  The server can stop
 * returning NFS4ERR_LEASE_MOVED to this client.  A RENEW operation
 * is appended to this compound to identify the client ID which is
 * performing recovery.
 */
static int _nfs40_proc_fsid_present(struct inode *inode, struct rpc_cred *cred)
{
        struct nfs_server *server = NFS_SERVER(inode);
        struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
        struct rpc_clnt *clnt = server->client;
        struct nfs4_fsid_present_arg args = {
                .fh             = NFS_FH(inode),
                .clientid       = clp->cl_clientid,
                .renew          = 1,            /* append RENEW */
        };
        struct nfs4_fsid_present_res res = {
                .renew          = 1,
        };
        struct rpc_message msg = {
                .rpc_proc       = &nfs4_procedures[NFSPROC4_CLNT_FSID_PRESENT],
                .rpc_argp       = &args,
                .rpc_resp       = &res,
                .rpc_cred       = cred,
        };
        unsigned long now = jiffies;
        int status;

        res.fh = nfs_alloc_fhandle();
        if (res.fh == NULL)
                return -ENOMEM;

        nfs4_init_sequence(&args.seq_args, &res.seq_res, 0);
        nfs4_set_sequence_privileged(&args.seq_args);
        status = nfs4_call_sync_sequence(clnt, server, &msg,
                                                &args.seq_args, &res.seq_res);
        nfs_free_fhandle(res.fh);
        if (status)
                return status;

        do_renew_lease(clp, now);
        return 0;
}

#ifdef CONFIG_NFS_V4_1

/*
 * This operation also signals the server that this client is
 * performing "lease moved" recovery.  The server can stop asserting
 * SEQ4_STATUS_LEASE_MOVED for this client.  The client ID performing
 * this operation is identified in the SEQUENCE operation in this
 * compound.
 */
static int _nfs41_proc_fsid_present(struct inode *inode, struct rpc_cred *cred)
{
        struct nfs_server *server = NFS_SERVER(inode);
        struct rpc_clnt *clnt = server->client;
        struct nfs4_fsid_present_arg args = {
                .fh             = NFS_FH(inode),
        };
        struct nfs4_fsid_present_res res = {
        };
        struct rpc_message msg = {
                .rpc_proc       = &nfs4_procedures[NFSPROC4_CLNT_FSID_PRESENT],
                .rpc_argp       = &args,
                .rpc_resp       = &res,
                .rpc_cred       = cred,
        };
        int status;

        res.fh = nfs_alloc_fhandle();
        if (res.fh == NULL)
                return -ENOMEM;

        nfs4_init_sequence(&args.seq_args, &res.seq_res, 0);
        nfs4_set_sequence_privileged(&args.seq_args);
        status = nfs4_call_sync_sequence(clnt, server, &msg,
                                                &args.seq_args, &res.seq_res);
        nfs_free_fhandle(res.fh);
        if (status == NFS4_OK &&
            res.seq_res.sr_status_flags & SEQ4_STATUS_LEASE_MOVED)
                status = -NFS4ERR_LEASE_MOVED;
        return status;
}

#endif  /* CONFIG_NFS_V4_1 */

/**
 * nfs4_proc_fsid_present - Is this FSID present or absent on server?
 * @inode: inode on FSID to check
 * @cred: credential to use for this operation
 *
 * Server indicates whether the FSID is present, moved, or not
 * recognized.  This operation is necessary to clear a LEASE_MOVED
 * condition for this client ID.
 *
 * Returns NFS4_OK if the FSID is present on this server,
 * -NFS4ERR_MOVED if the FSID is no longer present, a negative
 *  NFS4ERR code if some error occurred on the server, or a
 *  negative errno if a local failure occurred.
 */
int nfs4_proc_fsid_present(struct inode *inode, struct rpc_cred *cred)
{
        struct nfs_server *server = NFS_SERVER(inode);
        struct nfs_client *clp = server->nfs_client;
        const struct nfs4_mig_recovery_ops *ops =
                                        clp->cl_mvops->mig_recovery_ops;
        struct nfs4_exception exception = { };
        int status;

        dprintk("%s: FSID %llx:%llx on \"%s\"\n", __func__,
                (unsigned long long)server->fsid.major,
                (unsigned long long)server->fsid.minor,
                clp->cl_hostname);
        nfs_display_fhandle(NFS_FH(inode), __func__);

        do {
                status = ops->fsid_present(inode, cred);
                if (status != -NFS4ERR_DELAY)
                        break;
                nfs4_handle_exception(server, status, &exception);
        } while (exception.retry);
        return status;
}

/**
 * If 'use_integrity' is true and the state managment nfs_client
 * cl_rpcclient is using krb5i/p, use the integrity protected cl_rpcclient
 * and the machine credential as per RFC3530bis and RFC5661 Security
 * Considerations sections. Otherwise, just use the user cred with the
 * filesystem's rpc_client.
 */
static int _nfs4_proc_secinfo(struct inode *dir, const struct qstr *name, struct nfs4_secinfo_flavors *flavors, bool use_integrity)
{
        int status;
        struct nfs4_secinfo_arg args = {
                .dir_fh = NFS_FH(dir),
                .name   = name,
        };
        struct nfs4_secinfo_res res = {
                .flavors     = flavors,
        };
        struct rpc_message msg = {
                .rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_SECINFO],
                .rpc_argp = &args,
                .rpc_resp = &res,
        };
        struct rpc_clnt *clnt = NFS_SERVER(dir)->client;
        struct rpc_cred *cred = NULL;

        if (use_integrity) {
                clnt = NFS_SERVER(dir)->nfs_client->cl_rpcclient;
                cred = nfs4_get_clid_cred(NFS_SERVER(dir)->nfs_client);
                msg.rpc_cred = cred;
        }

        dprintk("NFS call  secinfo %s\n", name->name);

        nfs4_state_protect(NFS_SERVER(dir)->nfs_client,
                NFS_SP4_MACH_CRED_SECINFO, &clnt, &msg);

        status = nfs4_call_sync(clnt, NFS_SERVER(dir), &msg, &args.seq_args,
                                &res.seq_res, 0);
        dprintk("NFS reply  secinfo: %d\n", status);

        if (cred)
                put_rpccred(cred);

        return status;
}

int nfs4_proc_secinfo(struct inode *dir, const struct qstr *name,
                      struct nfs4_secinfo_flavors *flavors)
{
        struct nfs4_exception exception = { };
        int err;
        do {
                err = -NFS4ERR_WRONGSEC;

                /* try to use integrity protection with machine cred */
                if (_nfs4_is_integrity_protected(NFS_SERVER(dir)->nfs_client))
                        err = _nfs4_proc_secinfo(dir, name, flavors, true);

                /*
                 * if unable to use integrity protection, or SECINFO with
                 * integrity protection returns NFS4ERR_WRONGSEC (which is
                 * disallowed by spec, but exists in deployed servers) use
                 * the current filesystem's rpc_client and the user cred.
                 */
                if (err == -NFS4ERR_WRONGSEC)
                        err = _nfs4_proc_secinfo(dir, name, flavors, false);

                trace_nfs4_secinfo(dir, name, err);
                err = nfs4_handle_exception(NFS_SERVER(dir), err,
                                &exception);
        } while (exception.retry);
        return err;
}

#ifdef CONFIG_NFS_V4_1
/*
 * Check the exchange flags returned by the server for invalid flags, having
 * both PNFS and NON_PNFS flags set, and not having one of NON_PNFS, PNFS, or
 * DS flags set.
 */
static int nfs4_check_cl_exchange_flags(u32 flags, u32 version)
{
        if (version >= 2 && (flags & ~EXCHGID4_2_FLAG_MASK_R))
                goto out_inval;
        else if (version < 2 && (flags & ~EXCHGID4_FLAG_MASK_R))
                goto out_inval;
        if ((flags & EXCHGID4_FLAG_USE_PNFS_MDS) &&
            (flags & EXCHGID4_FLAG_USE_NON_PNFS))
                goto out_inval;
        if (!(flags & (EXCHGID4_FLAG_MASK_PNFS)))
                goto out_inval;
        return NFS_OK;
out_inval:
        return -NFS4ERR_INVAL;
}

static bool
nfs41_same_server_scope(struct nfs41_server_scope *a,
                        struct nfs41_server_scope *b)
{
        if (a->server_scope_sz != b->server_scope_sz)
                return false;
        return memcmp(a->server_scope, b->server_scope, a->server_scope_sz) == 0;
}

static void
nfs4_bind_one_conn_to_session_done(struct rpc_task *task, void *calldata)
{
}

static const struct rpc_call_ops nfs4_bind_one_conn_to_session_ops = {
        .rpc_call_done =  nfs4_bind_one_conn_to_session_done,
};

/*
 * nfs4_proc_bind_one_conn_to_session()
 *
 * The 4.1 client currently uses the same TCP connection for the
 * fore and backchannel.
 */
static
int nfs4_proc_bind_one_conn_to_session(struct rpc_clnt *clnt,
                struct rpc_xprt *xprt,
                struct nfs_client *clp,
                struct rpc_cred *cred)
{
        int status;
        struct nfs41_bind_conn_to_session_args args = {
                .client = clp,
                .dir = NFS4_CDFC4_FORE_OR_BOTH,
        };
        struct nfs41_bind_conn_to_session_res res;
        struct rpc_message msg = {
                .rpc_proc =
                        &nfs4_procedures[NFSPROC4_CLNT_BIND_CONN_TO_SESSION],
                .rpc_argp = &args,
                .rpc_resp = &res,
                .rpc_cred = cred,
        };
        struct rpc_task_setup task_setup_data = {
                .rpc_client = clnt,
                .rpc_xprt = xprt,
                .callback_ops = &nfs4_bind_one_conn_to_session_ops,
                .rpc_message = &msg,
                .flags = RPC_TASK_TIMEOUT,
        };
        struct rpc_task *task;

        nfs4_copy_sessionid(&args.sessionid, &clp->cl_session->sess_id);
        if (!(clp->cl_session->flags & SESSION4_BACK_CHAN))
                args.dir = NFS4_CDFC4_FORE;

        /* Do not set the backchannel flag unless this is clnt->cl_xprt */
        if (xprt != rcu_access_pointer(clnt->cl_xprt))
                args.dir = NFS4_CDFC4_FORE;

        task = rpc_run_task(&task_setup_data);
        if (!IS_ERR(task)) {
                status = task->tk_status;
                rpc_put_task(task);
        } else
                status = PTR_ERR(task);
        trace_nfs4_bind_conn_to_session(clp, status);
        if (status == 0) {
                if (memcmp(res.sessionid.data,
                    clp->cl_session->sess_id.data, NFS4_MAX_SESSIONID_LEN)) {
                        dprintk("NFS: %s: Session ID mismatch\n", __func__);
                        return -EIO;
                }
                if ((res.dir & args.dir) != res.dir || res.dir == 0) {
                        dprintk("NFS: %s: Unexpected direction from server\n",
                                __func__);
                        return -EIO;
                }
                if (res.use_conn_in_rdma_mode != args.use_conn_in_rdma_mode) {
                        dprintk("NFS: %s: Server returned RDMA mode = true\n",
                                __func__);
                        return -EIO;
                }
        }

        return status;
}

struct rpc_bind_conn_calldata {
        struct nfs_client *clp;
        struct rpc_cred *cred;
};

static int
nfs4_proc_bind_conn_to_session_callback(struct rpc_clnt *clnt,
                struct rpc_xprt *xprt,
                void *calldata)
{
        struct rpc_bind_conn_calldata *p = calldata;

        return nfs4_proc_bind_one_conn_to_session(clnt, xprt, p->clp, p->cred);
}

int nfs4_proc_bind_conn_to_session(struct nfs_client *clp, struct rpc_cred *cred)
{
        struct rpc_bind_conn_calldata data = {
                .clp = clp,
                .cred = cred,
        };
        return rpc_clnt_iterate_for_each_xprt(clp->cl_rpcclient,
                        nfs4_proc_bind_conn_to_session_callback, &data);
}

/*
 * Minimum set of SP4_MACH_CRED operations from RFC 5661 in the enforce map
 * and operations we'd like to see to enable certain features in the allow map
 */
static const struct nfs41_state_protection nfs4_sp4_mach_cred_request = {
        .how = SP4_MACH_CRED,
        .enforce.u.words = {
                [1] = 1 << (OP_BIND_CONN_TO_SESSION - 32) |
                      1 << (OP_EXCHANGE_ID - 32) |
                      1 << (OP_CREATE_SESSION - 32) |
                      1 << (OP_DESTROY_SESSION - 32) |
                      1 << (OP_DESTROY_CLIENTID - 32)
        },
        .allow.u.words = {
                [0] = 1 << (OP_CLOSE) |
                      1 << (OP_OPEN_DOWNGRADE) |
                      1 << (OP_LOCKU) |
                      1 << (OP_DELEGRETURN) |
                      1 << (OP_COMMIT),
                [1] = 1 << (OP_SECINFO - 32) |
                      1 << (OP_SECINFO_NO_NAME - 32) |
                      1 << (OP_LAYOUTRETURN - 32) |
                      1 << (OP_TEST_STATEID - 32) |
                      1 << (OP_FREE_STATEID - 32) |
                      1 << (OP_WRITE - 32)
        }
};

/*
 * Select the state protection mode for client `clp' given the server results
 * from exchange_id in `sp'.
 *
 * Returns 0 on success, negative errno otherwise.
 */
static int nfs4_sp4_select_mode(struct nfs_client *clp,
                                 struct nfs41_state_protection *sp)
{
        static const u32 supported_enforce[NFS4_OP_MAP_NUM_WORDS] = {
                [1] = 1 << (OP_BIND_CONN_TO_SESSION - 32) |
                      1 << (OP_EXCHANGE_ID - 32) |
                      1 << (OP_CREATE_SESSION - 32) |
                      1 << (OP_DESTROY_SESSION - 32) |
                      1 << (OP_DESTROY_CLIENTID - 32)
        };
        unsigned long flags = 0;
        unsigned int i;
        int ret = 0;

        if (sp->how == SP4_MACH_CRED) {
                /* Print state protect result */
                dfprintk(MOUNT, "Server SP4_MACH_CRED support:\n");
                for (i = 0; i <= LAST_NFS4_OP; i++) {
                        if (test_bit(i, sp->enforce.u.longs))
                                dfprintk(MOUNT, "  enforce op %d\n", i);
                        if (test_bit(i, sp->allow.u.longs))
                                dfprintk(MOUNT, "  allow op %d\n", i);
                }

                /* make sure nothing is on enforce list that isn't supported */
                for (i = 0; i < NFS4_OP_MAP_NUM_WORDS; i++) {
                        if (sp->enforce.u.words[i] & ~supported_enforce[i]) {
                                dfprintk(MOUNT, "sp4_mach_cred: disabled\n");
                                ret = -EINVAL;
                                goto out;
                        }
                }

                /*
                 * Minimal mode - state operations are allowed to use machine
                 * credential.  Note this already happens by default, so the
                 * client doesn't have to do anything more than the negotiation.
                 *
                 * NOTE: we don't care if EXCHANGE_ID is in the list -
                 *       we're already using the machine cred for exchange_id
                 *       and will never use a different cred.
                 */
                if (test_bit(OP_BIND_CONN_TO_SESSION, sp->enforce.u.longs) &&
                    test_bit(OP_CREATE_SESSION, sp->enforce.u.longs) &&
                    test_bit(OP_DESTROY_SESSION, sp->enforce.u.longs) &&
                    test_bit(OP_DESTROY_CLIENTID, sp->enforce.u.longs)) {
                        dfprintk(MOUNT, "sp4_mach_cred:\n");
                        dfprintk(MOUNT, "  minimal mode enabled\n");
                        __set_bit(NFS_SP4_MACH_CRED_MINIMAL, &flags);
                } else {
                        dfprintk(MOUNT, "sp4_mach_cred: disabled\n");
                        ret = -EINVAL;
                        goto out;
                }

                if (test_bit(OP_CLOSE, sp->allow.u.longs) &&
                    test_bit(OP_OPEN_DOWNGRADE, sp->allow.u.longs) &&
                    test_bit(OP_DELEGRETURN, sp->allow.u.longs) &&
                    test_bit(OP_LOCKU, sp->allow.u.longs)) {
                        dfprintk(MOUNT, "  cleanup mode enabled\n");
                        __set_bit(NFS_SP4_MACH_CRED_CLEANUP, &flags);
                }

                if (test_bit(OP_LAYOUTRETURN, sp->allow.u.longs)) {
                        dfprintk(MOUNT, "  pnfs cleanup mode enabled\n");
                        __set_bit(NFS_SP4_MACH_CRED_PNFS_CLEANUP, &flags);
                }

                if (test_bit(OP_SECINFO, sp->allow.u.longs) &&
                    test_bit(OP_SECINFO_NO_NAME, sp->allow.u.longs)) {
                        dfprintk(MOUNT, "  secinfo mode enabled\n");
                        __set_bit(NFS_SP4_MACH_CRED_SECINFO, &flags);
                }

                if (test_bit(OP_TEST_STATEID, sp->allow.u.longs) &&
                    test_bit(OP_FREE_STATEID, sp->allow.u.longs)) {
                        dfprintk(MOUNT, "  stateid mode enabled\n");
                        __set_bit(NFS_SP4_MACH_CRED_STATEID, &flags);
                }

                if (test_bit(OP_WRITE, sp->allow.u.longs)) {
                        dfprintk(MOUNT, "  write mode enabled\n");
                        __set_bit(NFS_SP4_MACH_CRED_WRITE, &flags);
                }

                if (test_bit(OP_COMMIT, sp->allow.u.longs)) {
                        dfprintk(MOUNT, "  commit mode enabled\n");
                        __set_bit(NFS_SP4_MACH_CRED_COMMIT, &flags);
                }
        }
out:
        clp->cl_sp4_flags = flags;
        return ret;
}

struct nfs41_exchange_id_data {
        struct nfs41_exchange_id_res res;
        struct nfs41_exchange_id_args args;
};

static void nfs4_exchange_id_release(void *data)
{
        struct nfs41_exchange_id_data *cdata =
                                        (struct nfs41_exchange_id_data *)data;

        nfs_put_client(cdata->args.client);
        kfree(cdata->res.impl_id);
        kfree(cdata->res.server_scope);
        kfree(cdata->res.server_owner);
        kfree(cdata);
}

static const struct rpc_call_ops nfs4_exchange_id_call_ops = {
        .rpc_release = nfs4_exchange_id_release,
};

/*
 * _nfs4_proc_exchange_id()
 *
 * Wrapper for EXCHANGE_ID operation.
 */
static struct rpc_task *
nfs4_run_exchange_id(struct nfs_client *clp, struct rpc_cred *cred,
                        u32 sp4_how, struct rpc_xprt *xprt)
{
        struct rpc_message msg = {
                .rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_EXCHANGE_ID],
                .rpc_cred = cred,
        };
        struct rpc_task_setup task_setup_data = {
                .rpc_client = clp->cl_rpcclient,
                .callback_ops = &nfs4_exchange_id_call_ops,
                .rpc_message = &msg,
                .flags = RPC_TASK_TIMEOUT,
        };
        struct nfs41_exchange_id_data *calldata;
        int status;

        if (!atomic_inc_not_zero(&clp->cl_count))
                return ERR_PTR(-EIO);

        status = -ENOMEM;
        calldata = kzalloc(sizeof(*calldata), GFP_NOFS);
        if (!calldata)
                goto out;

        nfs4_init_boot_verifier(clp, &calldata->args.verifier);

        status = nfs4_init_uniform_client_string(clp);
        if (status)
                goto out_calldata;

        calldata->res.server_owner = kzalloc(sizeof(struct nfs41_server_owner),
                                                GFP_NOFS);
        status = -ENOMEM;
        if (unlikely(calldata->res.server_owner == NULL))
                goto out_calldata;

        calldata->res.server_scope = kzalloc(sizeof(struct nfs41_server_scope),
                                        GFP_NOFS);
        if (unlikely(calldata->res.server_scope == NULL))
                goto out_server_owner;

        calldata->res.impl_id = kzalloc(sizeof(struct nfs41_impl_id), GFP_NOFS);
        if (unlikely(calldata->res.impl_id == NULL))
                goto out_server_scope;

        switch (sp4_how) {
        case SP4_NONE:
                calldata->args.state_protect.how = SP4_NONE;
                break;

        case SP4_MACH_CRED:
                calldata->args.state_protect = nfs4_sp4_mach_cred_request;
                break;

        default:
                /* unsupported! */
                WARN_ON_ONCE(1);
                status = -EINVAL;
                goto out_impl_id;
        }
        if (xprt) {
                task_setup_data.rpc_xprt = xprt;
                task_setup_data.flags |= RPC_TASK_SOFTCONN;
                memcpy(calldata->args.verifier.data, clp->cl_confirm.data,
                                sizeof(calldata->args.verifier.data));
        }
        calldata->args.client = clp;
        calldata->args.flags = EXCHGID4_FLAG_SUPP_MOVED_REFER |
        EXCHGID4_FLAG_BIND_PRINC_STATEID;
#ifdef CONFIG_NFS_V4_1_MIGRATION
        calldata->args.flags |= EXCHGID4_FLAG_SUPP_MOVED_MIGR;
#endif
        msg.rpc_argp = &calldata->args;
        msg.rpc_resp = &calldata->res;
        task_setup_data.callback_data = calldata;

        return rpc_run_task(&task_setup_data);

out_impl_id:
        kfree(calldata->res.impl_id);
out_server_scope:
        kfree(calldata->res.server_scope);
out_server_owner:
        kfree(calldata->res.server_owner);
out_calldata:
        kfree(calldata);
out:
        nfs_put_client(clp);
        return ERR_PTR(status);
}

/*
 * _nfs4_proc_exchange_id()
 *
 * Wrapper for EXCHANGE_ID operation.
 */
static int _nfs4_proc_exchange_id(struct nfs_client *clp, struct rpc_cred *cred,
                        u32 sp4_how)
{
        struct rpc_task *task;
        struct nfs41_exchange_id_args *argp;
        struct nfs41_exchange_id_res *resp;
        int status;

        task = nfs4_run_exchange_id(clp, cred, sp4_how, NULL);
        if (IS_ERR(task))
                return PTR_ERR(task);

        argp = task->tk_msg.rpc_argp;
        resp = task->tk_msg.rpc_resp;
        status = task->tk_status;
        if (status  != 0)
                goto out;

        status = nfs4_check_cl_exchange_flags(resp->flags,
                        clp->cl_mvops->minor_version);
        if (status  != 0)
                goto out;

        status = nfs4_sp4_select_mode(clp, &resp->state_protect);
        if (status != 0)
                goto out;

        clp->cl_clientid = resp->clientid;
        clp->cl_exchange_flags = resp->flags;
        clp->cl_seqid = resp->seqid;
        /* Client ID is not confirmed */
        if (!(resp->flags & EXCHGID4_FLAG_CONFIRMED_R))
                clear_bit(NFS4_SESSION_ESTABLISHED,
                          &clp->cl_session->session_state);

        if (clp->cl_serverscope != NULL &&
            !nfs41_same_server_scope(clp->cl_serverscope,
                                resp->server_scope)) {
                dprintk("%s: server_scope mismatch detected\n",
                        __func__);
                set_bit(NFS4CLNT_SERVER_SCOPE_MISMATCH, &clp->cl_state);
        }

        swap(clp->cl_serverowner, resp->server_owner);
        swap(clp->cl_serverscope, resp->server_scope);
        swap(clp->cl_implid, resp->impl_id);

        /* Save the EXCHANGE_ID verifier session trunk tests */
        memcpy(clp->cl_confirm.data, argp->verifier.data,
               sizeof(clp->cl_confirm.data));
out:
        trace_nfs4_exchange_id(clp, status);
        rpc_put_task(task);
        return status;
}

/*
 * nfs4_proc_exchange_id()
 *
 * Returns zero, a negative errno, or a negative NFS4ERR status code.
 *
 * Since the clientid has expired, all compounds using sessions
 * associated with the stale clientid will be returning
 * NFS4ERR_BADSESSION in the sequence operation, and will therefore
 * be in some phase of session reset.
 *
 * Will attempt to negotiate SP4_MACH_CRED if krb5i / krb5p auth is used.
 */
int nfs4_proc_exchange_id(struct nfs_client *clp, struct rpc_cred *cred)
{
        rpc_authflavor_t authflavor = clp->cl_rpcclient->cl_auth->au_flavor;
        int status;

        /* try SP4_MACH_CRED if krb5i/p */
        if (authflavor == RPC_AUTH_GSS_KRB5I ||
            authflavor == RPC_AUTH_GSS_KRB5P) {
                status = _nfs4_proc_exchange_id(clp, cred, SP4_MACH_CRED);
                if (!status)
                        return 0;
        }

        /* try SP4_NONE */
        return _nfs4_proc_exchange_id(clp, cred, SP4_NONE);
}

/**
 * nfs4_test_session_trunk
 *
 * This is an add_xprt_test() test function called from
 * rpc_clnt_setup_test_and_add_xprt.
 *
 * The rpc_xprt_switch is referrenced by rpc_clnt_setup_test_and_add_xprt
 * and is dereferrenced in nfs4_exchange_id_release
 *
 * Upon success, add the new transport to the rpc_clnt
 *
 * @clnt: struct rpc_clnt to get new transport
 * @xprt: the rpc_xprt to test
 * @data: call data for _nfs4_proc_exchange_id.
 */
int nfs4_test_session_trunk(struct rpc_clnt *clnt, struct rpc_xprt *xprt,
                            void *data)
{
        struct nfs4_add_xprt_data *adata = (struct nfs4_add_xprt_data *)data;
        struct rpc_task *task;
        int status;

        u32 sp4_how;

        dprintk("--> %s try %s\n", __func__,
                xprt->address_strings[RPC_DISPLAY_ADDR]);

        sp4_how = (adata->clp->cl_sp4_flags == 0 ? SP4_NONE : SP4_MACH_CRED);

        /* Test connection for session trunking. Async exchange_id call */
        task = nfs4_run_exchange_id(adata->clp, adata->cred, sp4_how, xprt);
        if (IS_ERR(task))
                return PTR_ERR(task);

        status = task->tk_status;
        if (status == 0)
                status = nfs4_detect_session_trunking(adata->clp,
                                task->tk_msg.rpc_resp, xprt);

        rpc_put_task(task);
        return status;
}
EXPORT_SYMBOL_GPL(nfs4_test_session_trunk);

static int _nfs4_proc_destroy_clientid(struct nfs_client *clp,
                struct rpc_cred *cred)
{
        struct rpc_message msg = {
                .rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_DESTROY_CLIENTID],
                .rpc_argp = clp,
                .rpc_cred = cred,
        };
        int status;

        status = rpc_call_sync(clp->cl_rpcclient, &msg, RPC_TASK_TIMEOUT);
        trace_nfs4_destroy_clientid(clp, status);
        if (status)
                dprintk("NFS: Got error %d from the server %s on "
                        "DESTROY_CLIENTID.", status, clp->cl_hostname);
        return status;
}

static int nfs4_proc_destroy_clientid(struct nfs_client *clp,
                struct rpc_cred *cred)
{
        unsigned int loop;
        int ret;

        for (loop = NFS4_MAX_LOOP_ON_RECOVER; loop != 0; loop--) {
                ret = _nfs4_proc_destroy_clientid(clp, cred);
                switch (ret) {
                case -NFS4ERR_DELAY:
                case -NFS4ERR_CLIENTID_BUSY:
                        ssleep(1);
                        break;
                default:
                        return ret;
                }
        }
        return 0;
}

int nfs4_destroy_clientid(struct nfs_client *clp)
{
        struct rpc_cred *cred;
        int ret = 0;

        if (clp->cl_mvops->minor_version < 1)
                goto out;
        if (clp->cl_exchange_flags == 0)
                goto out;
        if (clp->cl_preserve_clid)
                goto out;
        cred = nfs4_get_clid_cred(clp);
        ret = nfs4_proc_destroy_clientid(clp, cred);
        if (cred)
                put_rpccred(cred);
        switch (ret) {
        case 0:
        case -NFS4ERR_STALE_CLIENTID:
                clp->cl_exchange_flags = 0;
        }
out:
        return ret;
}

struct nfs4_get_lease_time_data {
        struct nfs4_get_lease_time_args *args;
        struct nfs4_get_lease_time_res *res;
        struct nfs_client *clp;
};

static void nfs4_get_lease_time_prepare(struct rpc_task *task,
                                        void *calldata)
{
        struct nfs4_get_lease_time_data *data =
                        (struct nfs4_get_lease_time_data *)calldata;

        dprintk("--> %s\n", __func__);
        /* just setup sequence, do not trigger session recovery
           since we're invoked within one */
        nfs4_setup_sequence(data->clp,
                        &data->args->la_seq_args,
                        &data->res->lr_seq_res,
                        task);
        dprintk("<-- %s\n", __func__);
}

/*
 * Called from nfs4_state_manager thread for session setup, so don't recover
 * from sequence operation or clientid errors.
 */
static void nfs4_get_lease_time_done(struct rpc_task *task, void *calldata)
{
        struct nfs4_get_lease_time_data *data =
                        (struct nfs4_get_lease_time_data *)calldata;

        dprintk("--> %s\n", __func__);
        if (!nfs41_sequence_done(task, &data->res->lr_seq_res))
                return;
        switch (task->tk_status) {
        case -NFS4ERR_DELAY:
        case -NFS4ERR_GRACE:
                dprintk("%s Retry: tk_status %d\n", __func__, task->tk_status);
                rpc_delay(task, NFS4_POLL_RETRY_MIN);
                task->tk_status = 0;
                /* fall through */
        case -NFS4ERR_RETRY_UNCACHED_REP:
                rpc_restart_call_prepare(task);
                return;
        }
        dprintk("<-- %s\n", __func__);
}

static const struct rpc_call_ops nfs4_get_lease_time_ops = {
        .rpc_call_prepare = nfs4_get_lease_time_prepare,
        .rpc_call_done = nfs4_get_lease_time_done,
};

int nfs4_proc_get_lease_time(struct nfs_client *clp, struct nfs_fsinfo *fsinfo)
{
        struct rpc_task *task;
        struct nfs4_get_lease_time_args args;
        struct nfs4_get_lease_time_res res = {
                .lr_fsinfo = fsinfo,
        };
        struct nfs4_get_lease_time_data data = {
                .args = &args,
                .res = &res,
                .clp = clp,
        };
        struct rpc_message msg = {
                .rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_GET_LEASE_TIME],
                .rpc_argp = &args,
                .rpc_resp = &res,
        };
        struct rpc_task_setup task_setup = {
                .rpc_client = clp->cl_rpcclient,
                .rpc_message = &msg,
                .callback_ops = &nfs4_get_lease_time_ops,
                .callback_data = &data,
                .flags = RPC_TASK_TIMEOUT,
        };
        int status;

        nfs4_init_sequence(&args.la_seq_args, &res.lr_seq_res, 0);
        nfs4_set_sequence_privileged(&args.la_seq_args);
        task = rpc_run_task(&task_setup);

        if (IS_ERR(task))
                return PTR_ERR(task);

        status = task->tk_status;
        rpc_put_task(task);
        return status;
}

/*
 * Initialize the values to be used by the client in CREATE_SESSION
 * If nfs4_init_session set the fore channel request and response sizes,
 * use them.
 *
 * Set the back channel max_resp_sz_cached to zero to force the client to
 * always set csa_cachethis to FALSE because the current implementation
 * of the back channel DRC only supports caching the CB_SEQUENCE operation.
 */
static void nfs4_init_channel_attrs(struct nfs41_create_session_args *args,
                                    struct rpc_clnt *clnt)
{
        unsigned int max_rqst_sz, max_resp_sz;
        unsigned int max_bc_payload = rpc_max_bc_payload(clnt);

        max_rqst_sz = NFS_MAX_FILE_IO_SIZE + nfs41_maxwrite_overhead;
        max_resp_sz = NFS_MAX_FILE_IO_SIZE + nfs41_maxread_overhead;

        /* Fore channel attributes */
        args->fc_attrs.max_rqst_sz = max_rqst_sz;
        args->fc_attrs.max_resp_sz = max_resp_sz;
        args->fc_attrs.max_ops = NFS4_MAX_OPS;
        args->fc_attrs.max_reqs = max_session_slots;

        dprintk("%s: Fore Channel : max_rqst_sz=%u max_resp_sz=%u "
                "max_ops=%u max_reqs=%u\n",
                __func__,
                args->fc_attrs.max_rqst_sz, args->fc_attrs.max_resp_sz,
                args->fc_attrs.max_ops, args->fc_attrs.max_reqs);

        /* Back channel attributes */
        args->bc_attrs.max_rqst_sz = max_bc_payload;
        args->bc_attrs.max_resp_sz = max_bc_payload;
        args->bc_attrs.max_resp_sz_cached = 0;
        args->bc_attrs.max_ops = NFS4_MAX_BACK_CHANNEL_OPS;
        args->bc_attrs.max_reqs = min_t(unsigned short, max_session_cb_slots, 1);

        dprintk("%s: Back Channel : max_rqst_sz=%u max_resp_sz=%u "
                "max_resp_sz_cached=%u max_ops=%u max_reqs=%u\n",
                __func__,
                args->bc_attrs.max_rqst_sz, args->bc_attrs.max_resp_sz,
                args->bc_attrs.max_resp_sz_cached, args->bc_attrs.max_ops,
                args->bc_attrs.max_reqs);
}

static int nfs4_verify_fore_channel_attrs(struct nfs41_create_session_args *args,
                struct nfs41_create_session_res *res)
{
        struct nfs4_channel_attrs *sent = &args->fc_attrs;
        struct nfs4_channel_attrs *rcvd = &res->fc_attrs;

        if (rcvd->max_resp_sz > sent->max_resp_sz)
                return -EINVAL;
        /*
         * Our requested max_ops is the minimum we need; we're not
         * prepared to break up compounds into smaller pieces than that.
         * So, no point even trying to continue if the server won't
         * cooperate:
         */
        if (rcvd->max_ops < sent->max_ops)
                return -EINVAL;
        if (rcvd->max_reqs == 0)
                return -EINVAL;
        if (rcvd->max_reqs > NFS4_MAX_SLOT_TABLE)
                rcvd->max_reqs = NFS4_MAX_SLOT_TABLE;
        return 0;
}

static int nfs4_verify_back_channel_attrs(struct nfs41_create_session_args *args,
                struct nfs41_create_session_res *res)
{
        struct nfs4_channel_attrs *sent = &args->bc_attrs;
        struct nfs4_channel_attrs *rcvd = &res->bc_attrs;

        if (!(res->flags & SESSION4_BACK_CHAN))
                goto out;
        if (rcvd->max_rqst_sz > sent->max_rqst_sz)
                return -EINVAL;
        if (rcvd->max_resp_sz < sent->max_resp_sz)
                return -EINVAL;
        if (rcvd->max_resp_sz_cached > sent->max_resp_sz_cached)
                return -EINVAL;
        if (rcvd->max_ops > sent->max_ops)
                return -EINVAL;
        if (rcvd->max_reqs > sent->max_reqs)
                return -EINVAL;
out:
        return 0;
}

static int nfs4_verify_channel_attrs(struct nfs41_create_session_args *args,
                                     struct nfs41_create_session_res *res)
{
        int ret;

        ret = nfs4_verify_fore_channel_attrs(args, res);
        if (ret)
                return ret;
        return nfs4_verify_back_channel_attrs(args, res);
}

static void nfs4_update_session(struct nfs4_session *session,
                struct nfs41_create_session_res *res)
{
        nfs4_copy_sessionid(&session->sess_id, &res->sessionid);
        /* Mark client id and session as being confirmed */
        session->clp->cl_exchange_flags |= EXCHGID4_FLAG_CONFIRMED_R;
        set_bit(NFS4_SESSION_ESTABLISHED, &session->session_state);
        session->flags = res->flags;
        memcpy(&session->fc_attrs, &res->fc_attrs, sizeof(session->fc_attrs));
        if (res->flags & SESSION4_BACK_CHAN)
                memcpy(&session->bc_attrs, &res->bc_attrs,
                                sizeof(session->bc_attrs));
}

static int _nfs4_proc_create_session(struct nfs_client *clp,
                struct rpc_cred *cred)
{
        struct nfs4_session *session = clp->cl_session;
        struct nfs41_create_session_args args = {
                .client = clp,
                .clientid = clp->cl_clientid,
                .seqid = clp->cl_seqid,
                .cb_program = NFS4_CALLBACK,
        };
        struct nfs41_create_session_res res;

        struct rpc_message msg = {
                .rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_CREATE_SESSION],
                .rpc_argp = &args,
                .rpc_resp = &res,
                .rpc_cred = cred,
        };
        int status;

        nfs4_init_channel_attrs(&args, clp->cl_rpcclient);
        args.flags = (SESSION4_PERSIST | SESSION4_BACK_CHAN);

        status = rpc_call_sync(session->clp->cl_rpcclient, &msg, RPC_TASK_TIMEOUT);
        trace_nfs4_create_session(clp, status);

        switch (status) {
        case -NFS4ERR_STALE_CLIENTID:
        case -NFS4ERR_DELAY:
        case -ETIMEDOUT:
        case -EACCES:
        case -EAGAIN:
                goto out;
        };

        clp->cl_seqid++;
        if (!status) {
                /* Verify the session's negotiated channel_attrs values */
                status = nfs4_verify_channel_attrs(&args, &res);
                /* Increment the clientid slot sequence id */
                if (status)
                        goto out;
                nfs4_update_session(session, &res);
        }
out:
        return status;
}

/*
 * Issues a CREATE_SESSION operation to the server.
 * It is the responsibility of the caller to verify the session is
 * expired before calling this routine.
 */
int nfs4_proc_create_session(struct nfs_client *clp, struct rpc_cred *cred)
{
        int status;
        unsigned *ptr;
        struct nfs4_session *session = clp->cl_session;

        dprintk("--> %s clp=%p session=%p\n", __func__, clp, session);

        status = _nfs4_proc_create_session(clp, cred);
        if (status)
                goto out;

        /* Init or reset the session slot tables */
        status = nfs4_setup_session_slot_tables(session);
        dprintk("slot table setup returned %d\n", status);
        if (status)
                goto out;

        ptr = (unsigned *)&session->sess_id.data[0];
        dprintk("%s client>seqid %d sessionid %u:%u:%u:%u\n", __func__,
                clp->cl_seqid, ptr[0], ptr[1], ptr[2], ptr[3]);
out:
        dprintk("<-- %s\n", __func__);
        return status;
}

/*
 * Issue the over-the-wire RPC DESTROY_SESSION.
 * The caller must serialize access to this routine.
 */
int nfs4_proc_destroy_session(struct nfs4_session *session,
                struct rpc_cred *cred)
{
        struct rpc_message msg = {
                .rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_DESTROY_SESSION],
                .rpc_argp = session,
                .rpc_cred = cred,
        };
        int status = 0;

        dprintk("--> nfs4_proc_destroy_session\n");

        /* session is still being setup */
        if (!test_and_clear_bit(NFS4_SESSION_ESTABLISHED, &session->session_state))
                return 0;

        status = rpc_call_sync(session->clp->cl_rpcclient, &msg, RPC_TASK_TIMEOUT);
        trace_nfs4_destroy_session(session->clp, status);

        if (status)
                dprintk("NFS: Got error %d from the server on DESTROY_SESSION. "
                        "Session has been destroyed regardless...\n", status);

        dprintk("<-- nfs4_proc_destroy_session\n");
        return status;
}

/*
 * Renew the cl_session lease.
 */
struct nfs4_sequence_data {
        struct nfs_client *clp;
        struct nfs4_sequence_args args;
        struct nfs4_sequence_res res;
};

static void nfs41_sequence_release(void *data)
{
        struct nfs4_sequence_data *calldata = data;
        struct nfs_client *clp = calldata->clp;

        if (atomic_read(&clp->cl_count) > 1)
                nfs4_schedule_state_renewal(clp);
        nfs_put_client(clp);
        kfree(calldata);
}

static int nfs41_sequence_handle_errors(struct rpc_task *task, struct nfs_client *clp)
{
        switch(task->tk_status) {
        case -NFS4ERR_DELAY:
                rpc_delay(task, NFS4_POLL_RETRY_MAX);
                return -EAGAIN;
        default:
                nfs4_schedule_lease_recovery(clp);
        }
        return 0;
}

static void nfs41_sequence_call_done(struct rpc_task *task, void *data)
{
        struct nfs4_sequence_data *calldata = data;
        struct nfs_client *clp = calldata->clp;

        if (!nfs41_sequence_done(task, task->tk_msg.rpc_resp))
                return;

        trace_nfs4_sequence(clp, task->tk_status);
        if (task->tk_status < 0) {
                dprintk("%s ERROR %d\n", __func__, task->tk_status);
                if (atomic_read(&clp->cl_count) == 1)
                        goto out;

                if (nfs41_sequence_handle_errors(task, clp) == -EAGAIN) {
                        rpc_restart_call_prepare(task);
                        return;
                }
        }
        dprintk("%s rpc_cred %p\n", __func__, task->tk_msg.rpc_cred);
out:
        dprintk("<-- %s\n", __func__);
}

static void nfs41_sequence_prepare(struct rpc_task *task, void *data)
{
        struct nfs4_sequence_data *calldata = data;
        struct nfs_client *clp = calldata->clp;
        struct nfs4_sequence_args *args;
        struct nfs4_sequence_res *res;

        args = task->tk_msg.rpc_argp;
        res = task->tk_msg.rpc_resp;

        nfs4_setup_sequence(clp, args, res, task);
}

static const struct rpc_call_ops nfs41_sequence_ops = {
        .rpc_call_done = nfs41_sequence_call_done,
        .rpc_call_prepare = nfs41_sequence_prepare,
        .rpc_release = nfs41_sequence_release,
};

static struct rpc_task *_nfs41_proc_sequence(struct nfs_client *clp,
                struct rpc_cred *cred,
                struct nfs4_slot *slot,
                bool is_privileged)
{
        struct nfs4_sequence_data *calldata;
        struct rpc_message msg = {
                .rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_SEQUENCE],
                .rpc_cred = cred,
        };
        struct rpc_task_setup task_setup_data = {
                .rpc_client = clp->cl_rpcclient,
                .rpc_message = &msg,
                .callback_ops = &nfs41_sequence_ops,
                .flags = RPC_TASK_ASYNC | RPC_TASK_TIMEOUT,
        };
        struct rpc_task *ret;

        ret = ERR_PTR(-EIO);
        if (!atomic_inc_not_zero(&clp->cl_count))
                goto out_err;

        ret = ERR_PTR(-ENOMEM);
        calldata = kzalloc(sizeof(*calldata), GFP_NOFS);
        if (calldata == NULL)
                goto out_put_clp;
        nfs4_init_sequence(&calldata->args, &calldata->res, 0);
        nfs4_sequence_attach_slot(&calldata->args, &calldata->res, slot);
        if (is_privileged)
                nfs4_set_sequence_privileged(&calldata->args);
        msg.rpc_argp = &calldata->args;
        msg.rpc_resp = &calldata->res;
        calldata->clp = clp;
        task_setup_data.callback_data = calldata;

        ret = rpc_run_task(&task_setup_data);
        if (IS_ERR(ret))
                goto out_err;
        return ret;
out_put_clp:
        nfs_put_client(clp);
out_err:
        nfs41_release_slot(slot);
        return ret;
}

static int nfs41_proc_async_sequence(struct nfs_client *clp, struct rpc_cred *cred, unsigned renew_flags)
{
        struct rpc_task *task;
        int ret = 0;

        if ((renew_flags & NFS4_RENEW_TIMEOUT) == 0)
                return -EAGAIN;
        task = _nfs41_proc_sequence(clp, cred, NULL, false);
        if (IS_ERR(task))
                ret = PTR_ERR(task);
        else
                rpc_put_task_async(task);
        dprintk("<-- %s status=%d\n", __func__, ret);
        return ret;
}

static int nfs4_proc_sequence(struct nfs_client *clp, struct rpc_cred *cred)
{
        struct rpc_task *task;
        int ret;

        task = _nfs41_proc_sequence(clp, cred, NULL, true);
        if (IS_ERR(task)) {
                ret = PTR_ERR(task);
                goto out;
        }
        ret = rpc_wait_for_completion_task(task);
        if (!ret)
                ret = task->tk_status;
        rpc_put_task(task);
out:
        dprintk("<-- %s status=%d\n", __func__, ret);
        return ret;
}

struct nfs4_reclaim_complete_data {
        struct nfs_client *clp;
        struct nfs41_reclaim_complete_args arg;
        struct nfs41_reclaim_complete_res res;
};

static void nfs4_reclaim_complete_prepare(struct rpc_task *task, void *data)
{
        struct nfs4_reclaim_complete_data *calldata = data;

        nfs4_setup_sequence(calldata->clp,
                        &calldata->arg.seq_args,
                        &calldata->res.seq_res,
                        task);
}

static int nfs41_reclaim_complete_handle_errors(struct rpc_task *task, struct nfs_client *clp)
{
        switch(task->tk_status) {
        case 0:
        case -NFS4ERR_COMPLETE_ALREADY:
        case -NFS4ERR_WRONG_CRED: /* What to do here? */
                break;
        case -NFS4ERR_DELAY:
                rpc_delay(task, NFS4_POLL_RETRY_MAX);
                /* fall through */
        case -NFS4ERR_RETRY_UNCACHED_REP:
                return -EAGAIN;
        case -NFS4ERR_BADSESSION:
        case -NFS4ERR_DEADSESSION:
        case -NFS4ERR_CONN_NOT_BOUND_TO_SESSION:
                nfs4_schedule_session_recovery(clp->cl_session,
                                task->tk_status);
                break;
        default:
                nfs4_schedule_lease_recovery(clp);
        }
        return 0;
}

static void nfs4_reclaim_complete_done(struct rpc_task *task, void *data)
{
        struct nfs4_reclaim_complete_data *calldata = data;
        struct nfs_client *clp = calldata->clp;
        struct nfs4_sequence_res *res = &calldata->res.seq_res;

        dprintk("--> %s\n", __func__);
        if (!nfs41_sequence_done(task, res))
                return;

        trace_nfs4_reclaim_complete(clp, task->tk_status);
        if (nfs41_reclaim_complete_handle_errors(task, clp) == -EAGAIN) {
                rpc_restart_call_prepare(task);
                return;
        }
        dprintk("<-- %s\n", __func__);
}

static void nfs4_free_reclaim_complete_data(void *data)
{
        struct nfs4_reclaim_complete_data *calldata = data;

        kfree(calldata);
}

static const struct rpc_call_ops nfs4_reclaim_complete_call_ops = {
        .rpc_call_prepare = nfs4_reclaim_complete_prepare,
        .rpc_call_done = nfs4_reclaim_complete_done,
        .rpc_release = nfs4_free_reclaim_complete_data,
};

/*
 * Issue a global reclaim complete.
 */
static int nfs41_proc_reclaim_complete(struct nfs_client *clp,
                struct rpc_cred *cred)
{
        struct nfs4_reclaim_complete_data *calldata;
        struct rpc_task *task;
        struct rpc_message msg = {
                .rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_RECLAIM_COMPLETE],
                .rpc_cred = cred,
        };
        struct rpc_task_setup task_setup_data = {
                .rpc_client = clp->cl_rpcclient,
                .rpc_message = &msg,
                .callback_ops = &nfs4_reclaim_complete_call_ops,
                .flags = RPC_TASK_ASYNC,
        };
        int status = -ENOMEM;

        dprintk("--> %s\n", __func__);
        calldata = kzalloc(sizeof(*calldata), GFP_NOFS);
        if (calldata == NULL)
                goto out;
        calldata->clp = clp;
        calldata->arg.one_fs = 0;

        nfs4_init_sequence(&calldata->arg.seq_args, &calldata->res.seq_res, 0);
        nfs4_set_sequence_privileged(&calldata->arg.seq_args);
        msg.rpc_argp = &calldata->arg;
        msg.rpc_resp = &calldata->res;
        task_setup_data.callback_data = calldata;
        task = rpc_run_task(&task_setup_data);
        if (IS_ERR(task)) {
                status = PTR_ERR(task);
                goto out;
        }
        status = rpc_wait_for_completion_task(task);
        if (status == 0)
                status = task->tk_status;
        rpc_put_task(task);
out:
        dprintk("<-- %s status=%d\n", __func__, status);
        return status;
}

static void
nfs4_layoutget_prepare(struct rpc_task *task, void *calldata)
{
        struct nfs4_layoutget *lgp = calldata;
        struct nfs_server *server = NFS_SERVER(lgp->args.inode);

        dprintk("--> %s\n", __func__);
        nfs4_setup_sequence(server->nfs_client, &lgp->args.seq_args,
                                &lgp->res.seq_res, task);
        dprintk("<-- %s\n", __func__);
}

static void nfs4_layoutget_done(struct rpc_task *task, void *calldata)
{
        struct nfs4_layoutget *lgp = calldata;

        dprintk("--> %s\n", __func__);
        nfs41_sequence_process(task, &lgp->res.seq_res);
        dprintk("<-- %s\n", __func__);
}

static int
nfs4_layoutget_handle_exception(struct rpc_task *task,
                struct nfs4_layoutget *lgp, struct nfs4_exception *exception)
{
        struct inode *inode = lgp->args.inode;
        struct nfs_server *server = NFS_SERVER(inode);
        struct pnfs_layout_hdr *lo;
        int nfs4err = task->tk_status;
        int err, status = 0;
        LIST_HEAD(head);

        dprintk("--> %s tk_status => %d\n", __func__, -task->tk_status);

        nfs4_sequence_free_slot(&lgp->res.seq_res);

        switch (nfs4err) {
        case 0:
                goto out;

        /*
         * NFS4ERR_LAYOUTUNAVAILABLE means we are not supposed to use pnfs
         * on the file. set tk_status to -ENODATA to tell upper layer to
         * retry go inband.
         */
        case -NFS4ERR_LAYOUTUNAVAILABLE:
                status = -ENODATA;
                goto out;
        /*
         * NFS4ERR_BADLAYOUT means the MDS cannot return a layout of
         * length lgp->args.minlength != 0 (see RFC5661 section 18.43.3).
         */
        case -NFS4ERR_BADLAYOUT:
                status = -EOVERFLOW;
                goto out;
        /*
         * NFS4ERR_LAYOUTTRYLATER is a conflict with another client
         * (or clients) writing to the same RAID stripe except when
         * the minlength argument is 0 (see RFC5661 section 18.43.3).
         *
         * Treat it like we would RECALLCONFLICT -- we retry for a little
         * while, and then eventually give up.
         */
        case -NFS4ERR_LAYOUTTRYLATER:
                if (lgp->args.minlength == 0) {
                        status = -EOVERFLOW;
                        goto out;
                }
                status = -EBUSY;
                break;
        case -NFS4ERR_RECALLCONFLICT:
                status = -ERECALLCONFLICT;
                break;
        case -NFS4ERR_DELEG_REVOKED:
        case -NFS4ERR_ADMIN_REVOKED:
        case -NFS4ERR_EXPIRED:
        case -NFS4ERR_BAD_STATEID:
                exception->timeout = 0;
                spin_lock(&inode->i_lock);
                lo = NFS_I(inode)->layout;
                /* If the open stateid was bad, then recover it. */
                if (!lo || test_bit(NFS_LAYOUT_INVALID_STID, &lo->plh_flags) ||
                    !nfs4_stateid_match_other(&lgp->args.stateid, &lo->plh_stateid)) {
                        spin_unlock(&inode->i_lock);
                        exception->state = lgp->args.ctx->state;
                        exception->stateid = &lgp->args.stateid;
                        break;
                }

                /*
                 * Mark the bad layout state as invalid, then retry
                 */
                pnfs_mark_layout_stateid_invalid(lo, &head);
                spin_unlock(&inode->i_lock);
                nfs_commit_inode(inode, 0);
                pnfs_free_lseg_list(&head);
                status = -EAGAIN;
                goto out;
        }

        err = nfs4_handle_exception(server, nfs4err, exception);
        if (!status) {
                if (exception->retry)
                        status = -EAGAIN;
                else
                        status = err;
        }
out:
        dprintk("<-- %s\n", __func__);
        return status;
}

static size_t max_response_pages(struct nfs_server *server)
{
        u32 max_resp_sz = server->nfs_client->cl_session->fc_attrs.max_resp_sz;
        return nfs_page_array_len(0, max_resp_sz);
}

static void nfs4_free_pages(struct page **pages, size_t size)
{
        int i;

        if (!pages)
                return;

        for (i = 0; i < size; i++) {
                if (!pages[i])
                        break;
                __free_page(pages[i]);
        }
        kfree(pages);
}

static struct page **nfs4_alloc_pages(size_t size, gfp_t gfp_flags)
{
        struct page **pages;
        int i;

        pages = kcalloc(size, sizeof(struct page *), gfp_flags);
        if (!pages) {
                dprintk("%s: can't alloc array of %zu pages\n", __func__, size);
                return NULL;
        }

        for (i = 0; i < size; i++) {
                pages[i] = alloc_page(gfp_flags);
                if (!pages[i]) {
                        dprintk("%s: failed to allocate page\n", __func__);
                        nfs4_free_pages(pages, size);
                        return NULL;
                }
        }

        return pages;
}

static void nfs4_layoutget_release(void *calldata)
{
        struct nfs4_layoutget *lgp = calldata;
        struct inode *inode = lgp->args.inode;
        struct nfs_server *server = NFS_SERVER(inode);
        size_t max_pages = max_response_pages(server);

        dprintk("--> %s\n", __func__);
        nfs4_sequence_free_slot(&lgp->res.seq_res);
        nfs4_free_pages(lgp->args.layout.pages, max_pages);
        pnfs_put_layout_hdr(NFS_I(inode)->layout);
        put_nfs_open_context(lgp->args.ctx);
        kfree(calldata);
        dprintk("<-- %s\n", __func__);
}

static const struct rpc_call_ops nfs4_layoutget_call_ops = {
        .rpc_call_prepare = nfs4_layoutget_prepare,
        .rpc_call_done = nfs4_layoutget_done,
        .rpc_release = nfs4_layoutget_release,
};

struct pnfs_layout_segment *
nfs4_proc_layoutget(struct nfs4_layoutget *lgp, long *timeout, gfp_t gfp_flags)
{
        struct inode *inode = lgp->args.inode;
        struct nfs_server *server = NFS_SERVER(inode);
        size_t max_pages = max_response_pages(server);
        struct rpc_task *task;
        struct rpc_message msg = {
                .rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_LAYOUTGET],
                .rpc_argp = &lgp->args,
                .rpc_resp = &lgp->res,
                .rpc_cred = lgp->cred,
        };
        struct rpc_task_setup task_setup_data = {
                .rpc_client = server->client,
                .rpc_message = &msg,
                .callback_ops = &nfs4_layoutget_call_ops,
                .callback_data = lgp,
                .flags = RPC_TASK_ASYNC,
        };
        struct pnfs_layout_segment *lseg = NULL;
        struct nfs4_exception exception = {
                .inode = inode,
                .timeout = *timeout,
        };
        int status = 0;

        dprintk("--> %s\n", __func__);

        /* nfs4_layoutget_release calls pnfs_put_layout_hdr */
        pnfs_get_layout_hdr(NFS_I(inode)->layout);

        lgp->args.layout.pages = nfs4_alloc_pages(max_pages, gfp_flags);
        if (!lgp->args.layout.pages) {
                nfs4_layoutget_release(lgp);
                return ERR_PTR(-ENOMEM);
        }
        lgp->args.layout.pglen = max_pages * PAGE_SIZE;

        lgp->res.layoutp = &lgp->args.layout;
        lgp->res.seq_res.sr_slot = NULL;
        nfs4_init_sequence(&lgp->args.seq_args, &lgp->res.seq_res, 0);

        task = rpc_run_task(&task_setup_data);
        if (IS_ERR(task))
                return ERR_CAST(task);
        status = rpc_wait_for_completion_task(task);
        if (status != 0)
                goto out;

        /* if layoutp->len is 0, nfs4_layoutget_prepare called rpc_exit */
        if (task->tk_status < 0 || lgp->res.layoutp->len == 0) {
                status = nfs4_layoutget_handle_exception(task, lgp, &exception);
                *timeout = exception.timeout;
        } else
                lseg = pnfs_layout_process(lgp);
out:
        trace_nfs4_layoutget(lgp->args.ctx,
                        &lgp->args.range,
                        &lgp->res.range,
                        &lgp->res.stateid,
                        status);

        rpc_put_task(task);
        dprintk("<-- %s status=%d\n", __func__, status);
        if (status)
                return ERR_PTR(status);
        return lseg;
}

static void
nfs4_layoutreturn_prepare(struct rpc_task *task, void *calldata)
{
        struct nfs4_layoutreturn *lrp = calldata;

        dprintk("--> %s\n", __func__);
        nfs4_setup_sequence(lrp->clp,
                        &lrp->args.seq_args,
                        &lrp->res.seq_res,
                        task);
}

static void nfs4_layoutreturn_done(struct rpc_task *task, void *calldata)
{
        struct nfs4_layoutreturn *lrp = calldata;
        struct nfs_server *server;

        dprintk("--> %s\n", __func__);

        if (!nfs41_sequence_process(task, &lrp->res.seq_res))
                return;

        server = NFS_SERVER(lrp->args.inode);
        switch (task->tk_status) {
        default:
                task->tk_status = 0;
        case 0:
                break;
        case -NFS4ERR_DELAY:
                if (nfs4_async_handle_error(task, server, NULL, NULL) != -EAGAIN)
                        break;
                nfs4_sequence_free_slot(&lrp->res.seq_res);
                rpc_restart_call_prepare(task);
                return;
        }
        dprintk("<-- %s\n", __func__);
}

static void nfs4_layoutreturn_release(void *calldata)
{
        struct nfs4_layoutreturn *lrp = calldata;
        struct pnfs_layout_hdr *lo = lrp->args.layout;

        dprintk("--> %s\n", __func__);
        pnfs_layoutreturn_free_lsegs(lo, &lrp->args.stateid, &lrp->args.range,
                        lrp->res.lrs_present ? &lrp->res.stateid : NULL);
        nfs4_sequence_free_slot(&lrp->res.seq_res);
        if (lrp->ld_private.ops && lrp->ld_private.ops->free)
                lrp->ld_private.ops->free(&lrp->ld_private);
        pnfs_put_layout_hdr(lrp->args.layout);
        nfs_iput_and_deactive(lrp->inode);
        kfree(calldata);
        dprintk("<-- %s\n", __func__);
}

static const struct rpc_call_ops nfs4_layoutreturn_call_ops = {
        .rpc_call_prepare = nfs4_layoutreturn_prepare,
        .rpc_call_done = nfs4_layoutreturn_done,
        .rpc_release = nfs4_layoutreturn_release,
};

int nfs4_proc_layoutreturn(struct nfs4_layoutreturn *lrp, bool sync)
{
        struct rpc_task *task;
        struct rpc_message msg = {
                .rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_LAYOUTRETURN],
                .rpc_argp = &lrp->args,
                .rpc_resp = &lrp->res,
                .rpc_cred = lrp->cred,
        };
        struct rpc_task_setup task_setup_data = {
                .rpc_client = NFS_SERVER(lrp->args.inode)->client,
                .rpc_message = &msg,
                .callback_ops = &nfs4_layoutreturn_call_ops,
                .callback_data = lrp,
        };
        int status = 0;

        nfs4_state_protect(NFS_SERVER(lrp->args.inode)->nfs_client,
                        NFS_SP4_MACH_CRED_PNFS_CLEANUP,
                        &task_setup_data.rpc_client, &msg);

        dprintk("--> %s\n", __func__);
        if (!sync) {
                lrp->inode = nfs_igrab_and_active(lrp->args.inode);
                if (!lrp->inode) {
                        nfs4_layoutreturn_release(lrp);
                        return -EAGAIN;
                }
                task_setup_data.flags |= RPC_TASK_ASYNC;
        }
        nfs4_init_sequence(&lrp->args.seq_args, &lrp->res.seq_res, 1);
        task = rpc_run_task(&task_setup_data);
        if (IS_ERR(task))
                return PTR_ERR(task);
        if (sync)
                status = task->tk_status;
        trace_nfs4_layoutreturn(lrp->args.inode, &lrp->args.stateid, status);
        dprintk("<-- %s status=%d\n", __func__, status);
        rpc_put_task(task);
        return status;
}

static int
_nfs4_proc_getdeviceinfo(struct nfs_server *server,
                struct pnfs_device *pdev,
                struct rpc_cred *cred)
{
        struct nfs4_getdeviceinfo_args args = {
                .pdev = pdev,
                .notify_types = NOTIFY_DEVICEID4_CHANGE |
                        NOTIFY_DEVICEID4_DELETE,
        };
        struct nfs4_getdeviceinfo_res res = {
                .pdev = pdev,
        };
        struct rpc_message msg = {
                .rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_GETDEVICEINFO],
                .rpc_argp = &args,
                .rpc_resp = &res,
                .rpc_cred = cred,
        };
        int status;

        dprintk("--> %s\n", __func__);
        status = nfs4_call_sync(server->client, server, &msg, &args.seq_args, &res.seq_res, 0);
        if (res.notification & ~args.notify_types)
                dprintk("%s: unsupported notification\n", __func__);
        if (res.notification != args.notify_types)
                pdev->nocache = 1;

        dprintk("<-- %s status=%d\n", __func__, status);

        return status;
}

int nfs4_proc_getdeviceinfo(struct nfs_server *server,
                struct pnfs_device *pdev,
                struct rpc_cred *cred)
{
        struct nfs4_exception exception = { };
        int err;

        do {
                err = nfs4_handle_exception(server,
                                        _nfs4_proc_getdeviceinfo(server, pdev, cred),
                                        &exception);
        } while (exception.retry);
        return err;
}
EXPORT_SYMBOL_GPL(nfs4_proc_getdeviceinfo);

static void nfs4_layoutcommit_prepare(struct rpc_task *task, void *calldata)
{
        struct nfs4_layoutcommit_data *data = calldata;
        struct nfs_server *server = NFS_SERVER(data->args.inode);

        nfs4_setup_sequence(server->nfs_client,
                        &data->args.seq_args,
                        &data->res.seq_res,
                        task);
}

static void
nfs4_layoutcommit_done(struct rpc_task *task, void *calldata)
{
        struct nfs4_layoutcommit_data *data = calldata;
        struct nfs_server *server = NFS_SERVER(data->args.inode);

        if (!nfs41_sequence_done(task, &data->res.seq_res))
                return;

        switch (task->tk_status) { /* Just ignore these failures */
        case -NFS4ERR_DELEG_REVOKED: /* layout was recalled */
        case -NFS4ERR_BADIOMODE:     /* no IOMODE_RW layout for range */
        case -NFS4ERR_BADLAYOUT:     /* no layout */
        case -NFS4ERR_GRACE:        /* loca_recalim always false */
                task->tk_status = 0;
        case 0:
                break;
        default:
                if (nfs4_async_handle_error(task, server, NULL, NULL) == -EAGAIN) {
                        rpc_restart_call_prepare(task);
                        return;
                }
        }
}

static void nfs4_layoutcommit_release(void *calldata)
{
        struct nfs4_layoutcommit_data *data = calldata;

        pnfs_cleanup_layoutcommit(data);
        nfs_post_op_update_inode_force_wcc(data->args.inode,
                                           data->res.fattr);
        put_rpccred(data->cred);
        nfs_iput_and_deactive(data->inode);
        kfree(data);
}

static const struct rpc_call_ops nfs4_layoutcommit_ops = {
        .rpc_call_prepare = nfs4_layoutcommit_prepare,
        .rpc_call_done = nfs4_layoutcommit_done,
        .rpc_release = nfs4_layoutcommit_release,
};

int
nfs4_proc_layoutcommit(struct nfs4_layoutcommit_data *data, bool sync)
{
        struct rpc_message msg = {
                .rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_LAYOUTCOMMIT],
                .rpc_argp = &data->args,
                .rpc_resp = &data->res,
                .rpc_cred = data->cred,
        };
        struct rpc_task_setup task_setup_data = {
                .task = &data->task,
                .rpc_client = NFS_CLIENT(data->args.inode),
                .rpc_message = &msg,
                .callback_ops = &nfs4_layoutcommit_ops,
                .callback_data = data,
        };
        struct rpc_task *task;
        int status = 0;

        dprintk("NFS: initiating layoutcommit call. sync %d "
                "lbw: %llu inode %lu\n", sync,
                data->args.lastbytewritten,
                data->args.inode->i_ino);

        if (!sync) {
                data->inode = nfs_igrab_and_active(data->args.inode);
                if (data->inode == NULL) {
                        nfs4_layoutcommit_release(data);
                        return -EAGAIN;
                }
                task_setup_data.flags = RPC_TASK_ASYNC;
        }
        nfs4_init_sequence(&data->args.seq_args, &data->res.seq_res, 1);
        task = rpc_run_task(&task_setup_data);
        if (IS_ERR(task))
                return PTR_ERR(task);
        if (sync)
                status = task->tk_status;
        trace_nfs4_layoutcommit(data->args.inode, &data->args.stateid, status);
        dprintk("%s: status %d\n", __func__, status);
        rpc_put_task(task);
        return status;
}

/**
 * Use the state managment nfs_client cl_rpcclient, which uses krb5i (if
 * possible) as per RFC3530bis and RFC5661 Security Considerations sections
 */
static int
_nfs41_proc_secinfo_no_name(struct nfs_server *server, struct nfs_fh *fhandle,
                    struct nfs_fsinfo *info,
                    struct nfs4_secinfo_flavors *flavors, bool use_integrity)
{
        struct nfs41_secinfo_no_name_args args = {
                .style = SECINFO_STYLE_CURRENT_FH,
        };
        struct nfs4_secinfo_res res = {
                .flavors = flavors,
        };
        struct rpc_message msg = {
                .rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_SECINFO_NO_NAME],
                .rpc_argp = &args,
                .rpc_resp = &res,
        };
        struct rpc_clnt *clnt = server->client;
        struct rpc_cred *cred = NULL;
        int status;

        if (use_integrity) {
                clnt = server->nfs_client->cl_rpcclient;
                cred = nfs4_get_clid_cred(server->nfs_client);
                msg.rpc_cred = cred;
        }

        dprintk("--> %s\n", __func__);
        status = nfs4_call_sync(clnt, server, &msg, &args.seq_args,
                                &res.seq_res, 0);
        dprintk("<-- %s status=%d\n", __func__, status);

        if (cred)
                put_rpccred(cred);

        return status;
}

static int
nfs41_proc_secinfo_no_name(struct nfs_server *server, struct nfs_fh *fhandle,
                           struct nfs_fsinfo *info, struct nfs4_secinfo_flavors *flavors)
{
        struct nfs4_exception exception = { };
        int err;
        do {
                /* first try using integrity protection */
                err = -NFS4ERR_WRONGSEC;

                /* try to use integrity protection with machine cred */
                if (_nfs4_is_integrity_protected(server->nfs_client))
                        err = _nfs41_proc_secinfo_no_name(server, fhandle, info,
                                                          flavors, true);

                /*
                 * if unable to use integrity protection, or SECINFO with
                 * integrity protection returns NFS4ERR_WRONGSEC (which is
                 * disallowed by spec, but exists in deployed servers) use
                 * the current filesystem's rpc_client and the user cred.
                 */
                if (err == -NFS4ERR_WRONGSEC)
                        err = _nfs41_proc_secinfo_no_name(server, fhandle, info,
                                                          flavors, false);

                switch (err) {
                case 0:
                case -NFS4ERR_WRONGSEC:
                case -ENOTSUPP:
                        goto out;
                default:
                        err = nfs4_handle_exception(server, err, &exception);
                }
        } while (exception.retry);
out:
        return err;
}

static int
nfs41_find_root_sec(struct nfs_server *server, struct nfs_fh *fhandle,
                    struct nfs_fsinfo *info)
{
        int err;
        struct page *page;
        rpc_authflavor_t flavor = RPC_AUTH_MAXFLAVOR;
        struct nfs4_secinfo_flavors *flavors;
        struct nfs4_secinfo4 *secinfo;
        int i;

        page = alloc_page(GFP_KERNEL);
        if (!page) {
                err = -ENOMEM;
                goto out;
        }

        flavors = page_address(page);
        err = nfs41_proc_secinfo_no_name(server, fhandle, info, flavors);

        /*
         * Fall back on "guess and check" method if
         * the server doesn't support SECINFO_NO_NAME
         */
        if (err == -NFS4ERR_WRONGSEC || err == -ENOTSUPP) {
                err = nfs4_find_root_sec(server, fhandle, info);
                goto out_freepage;
        }
        if (err)
                goto out_freepage;

        for (i = 0; i < flavors->num_flavors; i++) {
                secinfo = &flavors->flavors[i];

                switch (secinfo->flavor) {
                case RPC_AUTH_NULL:
                case RPC_AUTH_UNIX:
                case RPC_AUTH_GSS:
                        flavor = rpcauth_get_pseudoflavor(secinfo->flavor,
                                        &secinfo->flavor_info);
                        break;
                default:
                        flavor = RPC_AUTH_MAXFLAVOR;
                        break;
                }

                if (!nfs_auth_info_match(&server->auth_info, flavor))
                        flavor = RPC_AUTH_MAXFLAVOR;

                if (flavor != RPC_AUTH_MAXFLAVOR) {
                        err = nfs4_lookup_root_sec(server, fhandle,
                                                   info, flavor);
                        if (!err)
                                break;
                }
        }

        if (flavor == RPC_AUTH_MAXFLAVOR)
                err = -EPERM;

out_freepage:
        put_page(page);
        if (err == -EACCES)
                return -EPERM;
out:
        return err;
}

static int _nfs41_test_stateid(struct nfs_server *server,
                nfs4_stateid *stateid,
                struct rpc_cred *cred)
{
        int status;
        struct nfs41_test_stateid_args args = {
                .stateid = stateid,
        };
        struct nfs41_test_stateid_res res;
        struct rpc_message msg = {
                .rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_TEST_STATEID],
                .rpc_argp = &args,
                .rpc_resp = &res,
                .rpc_cred = cred,
        };
        struct rpc_clnt *rpc_client = server->client;

        nfs4_state_protect(server->nfs_client, NFS_SP4_MACH_CRED_STATEID,
                &rpc_client, &msg);

        dprintk("NFS call  test_stateid %p\n", stateid);
        nfs4_init_sequence(&args.seq_args, &res.seq_res, 0);
        nfs4_set_sequence_privileged(&args.seq_args);
        status = nfs4_call_sync_sequence(rpc_client, server, &msg,
                        &args.seq_args, &res.seq_res);
        if (status != NFS_OK) {
                dprintk("NFS reply test_stateid: failed, %d\n", status);
                return status;
        }
        dprintk("NFS reply test_stateid: succeeded, %d\n", -res.status);
        return -res.status;
}

static void nfs4_handle_delay_or_session_error(struct nfs_server *server,
                int err, struct nfs4_exception *exception)
{
        exception->retry = 0;
        switch(err) {
        case -NFS4ERR_DELAY:
        case -NFS4ERR_RETRY_UNCACHED_REP:
                nfs4_handle_exception(server, err, exception);
                break;
        case -NFS4ERR_BADSESSION:
        case -NFS4ERR_BADSLOT:
        case -NFS4ERR_BAD_HIGH_SLOT:
        case -NFS4ERR_CONN_NOT_BOUND_TO_SESSION:
        case -NFS4ERR_DEADSESSION:
                nfs4_do_handle_exception(server, err, exception);
        }
}

/**
 * nfs41_test_stateid - perform a TEST_STATEID operation
 *
 * @server: server / transport on which to perform the operation
 * @stateid: state ID to test
 * @cred: credential
 *
 * Returns NFS_OK if the server recognizes that "stateid" is valid.
 * Otherwise a negative NFS4ERR value is returned if the operation
 * failed or the state ID is not currently valid.
 */
static int nfs41_test_stateid(struct nfs_server *server,
                nfs4_stateid *stateid,
                struct rpc_cred *cred)
{
        struct nfs4_exception exception = { };
        int err;
        do {
                err = _nfs41_test_stateid(server, stateid, cred);
                nfs4_handle_delay_or_session_error(server, err, &exception);
        } while (exception.retry);
        return err;
}

struct nfs_free_stateid_data {
        struct nfs_server *server;
        struct nfs41_free_stateid_args args;
        struct nfs41_free_stateid_res res;
};

static void nfs41_free_stateid_prepare(struct rpc_task *task, void *calldata)
{
        struct nfs_free_stateid_data *data = calldata;
        nfs4_setup_sequence(data->server->nfs_client,
                        &data->args.seq_args,
                        &data->res.seq_res,
                        task);
}

static void nfs41_free_stateid_done(struct rpc_task *task, void *calldata)
{
        struct nfs_free_stateid_data *data = calldata;

        nfs41_sequence_done(task, &data->res.seq_res);

        switch (task->tk_status) {
        case -NFS4ERR_DELAY:
                if (nfs4_async_handle_error(task, data->server, NULL, NULL) == -EAGAIN)
                        rpc_restart_call_prepare(task);
        }
}

static void nfs41_free_stateid_release(void *calldata)
{
        kfree(calldata);
}

static const struct rpc_call_ops nfs41_free_stateid_ops = {
        .rpc_call_prepare = nfs41_free_stateid_prepare,
        .rpc_call_done = nfs41_free_stateid_done,
        .rpc_release = nfs41_free_stateid_release,
};

static struct rpc_task *_nfs41_free_stateid(struct nfs_server *server,
                const nfs4_stateid *stateid,
                struct rpc_cred *cred,
                bool privileged)
{
        struct rpc_message msg = {
                .rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_FREE_STATEID],
                .rpc_cred = cred,
        };
        struct rpc_task_setup task_setup = {
                .rpc_client = server->client,
                .rpc_message = &msg,
                .callback_ops = &nfs41_free_stateid_ops,
                .flags = RPC_TASK_ASYNC,
        };
        struct nfs_free_stateid_data *data;

        nfs4_state_protect(server->nfs_client, NFS_SP4_MACH_CRED_STATEID,
                &task_setup.rpc_client, &msg);

        dprintk("NFS call  free_stateid %p\n", stateid);
        data = kmalloc(sizeof(*data), GFP_NOFS);
        if (!data)
                return ERR_PTR(-ENOMEM);
        data->server = server;
        nfs4_stateid_copy(&data->args.stateid, stateid);

        task_setup.callback_data = data;

        msg.rpc_argp = &data->args;
        msg.rpc_resp = &data->res;
        nfs4_init_sequence(&data->args.seq_args, &data->res.seq_res, 1);
        if (privileged)
                nfs4_set_sequence_privileged(&data->args.seq_args);

        return rpc_run_task(&task_setup);
}

/**
 * nfs41_free_stateid - perform a FREE_STATEID operation
 *
 * @server: server / transport on which to perform the operation
 * @stateid: state ID to release
 * @cred: credential
 * @is_recovery: set to true if this call needs to be privileged
 *
 * Note: this function is always asynchronous.
 */
static int nfs41_free_stateid(struct nfs_server *server,
                const nfs4_stateid *stateid,
                struct rpc_cred *cred,
                bool is_recovery)
{
        struct rpc_task *task;

        task = _nfs41_free_stateid(server, stateid, cred, is_recovery);
        if (IS_ERR(task))
                return PTR_ERR(task);
        rpc_put_task(task);
        return 0;
}

static void
nfs41_free_lock_state(struct nfs_server *server, struct nfs4_lock_state *lsp)
{
        struct rpc_cred *cred = lsp->ls_state->owner->so_cred;

        nfs41_free_stateid(server, &lsp->ls_stateid, cred, false);
        nfs4_free_lock_state(server, lsp);
}

static bool nfs41_match_stateid(const nfs4_stateid *s1,
                const nfs4_stateid *s2)
{
        if (s1->type != s2->type)
                return false;

        if (memcmp(s1->other, s2->other, sizeof(s1->other)) != 0)
                return false;

        if (s1->seqid == s2->seqid)
                return true;

        return s1->seqid == 0 || s2->seqid == 0;
}

#endif /* CONFIG_NFS_V4_1 */

static bool nfs4_match_stateid(const nfs4_stateid *s1,
                const nfs4_stateid *s2)
{
        return nfs4_stateid_match(s1, s2);
}


static const struct nfs4_state_recovery_ops nfs40_reboot_recovery_ops = {
        .owner_flag_bit = NFS_OWNER_RECLAIM_REBOOT,
        .state_flag_bit = NFS_STATE_RECLAIM_REBOOT,
        .recover_open   = nfs4_open_reclaim,
        .recover_lock   = nfs4_lock_reclaim,
        .establish_clid = nfs4_init_clientid,
        .detect_trunking = nfs40_discover_server_trunking,
};

#if defined(CONFIG_NFS_V4_1)
static const struct nfs4_state_recovery_ops nfs41_reboot_recovery_ops = {
        .owner_flag_bit = NFS_OWNER_RECLAIM_REBOOT,
        .state_flag_bit = NFS_STATE_RECLAIM_REBOOT,
        .recover_open   = nfs4_open_reclaim,
        .recover_lock   = nfs4_lock_reclaim,
        .establish_clid = nfs41_init_clientid,
        .reclaim_complete = nfs41_proc_reclaim_complete,
        .detect_trunking = nfs41_discover_server_trunking,
};
#endif /* CONFIG_NFS_V4_1 */

static const struct nfs4_state_recovery_ops nfs40_nograce_recovery_ops = {
        .owner_flag_bit = NFS_OWNER_RECLAIM_NOGRACE,
        .state_flag_bit = NFS_STATE_RECLAIM_NOGRACE,
        .recover_open   = nfs40_open_expired,
        .recover_lock   = nfs4_lock_expired,
        .establish_clid = nfs4_init_clientid,
};

#if defined(CONFIG_NFS_V4_1)
static const struct nfs4_state_recovery_ops nfs41_nograce_recovery_ops = {
        .owner_flag_bit = NFS_OWNER_RECLAIM_NOGRACE,
        .state_flag_bit = NFS_STATE_RECLAIM_NOGRACE,
        .recover_open   = nfs41_open_expired,
        .recover_lock   = nfs41_lock_expired,
        .establish_clid = nfs41_init_clientid,
};
#endif /* CONFIG_NFS_V4_1 */

static const struct nfs4_state_maintenance_ops nfs40_state_renewal_ops = {
        .sched_state_renewal = nfs4_proc_async_renew,
        .get_state_renewal_cred_locked = nfs4_get_renew_cred_locked,
        .renew_lease = nfs4_proc_renew,
};

#if defined(CONFIG_NFS_V4_1)
static const struct nfs4_state_maintenance_ops nfs41_state_renewal_ops = {
        .sched_state_renewal = nfs41_proc_async_sequence,
        .get_state_renewal_cred_locked = nfs4_get_machine_cred_locked,
        .renew_lease = nfs4_proc_sequence,
};
#endif

static const struct nfs4_mig_recovery_ops nfs40_mig_recovery_ops = {
        .get_locations = _nfs40_proc_get_locations,
        .fsid_present = _nfs40_proc_fsid_present,
};

#if defined(CONFIG_NFS_V4_1)
static const struct nfs4_mig_recovery_ops nfs41_mig_recovery_ops = {
        .get_locations = _nfs41_proc_get_locations,
        .fsid_present = _nfs41_proc_fsid_present,
};
#endif  /* CONFIG_NFS_V4_1 */

static const struct nfs4_minor_version_ops nfs_v4_0_minor_ops = {
        .minor_version = 0,
        .init_caps = NFS_CAP_READDIRPLUS
                | NFS_CAP_ATOMIC_OPEN
                | NFS_CAP_POSIX_LOCK,
        .init_client = nfs40_init_client,
        .shutdown_client = nfs40_shutdown_client,
        .match_stateid = nfs4_match_stateid,
        .find_root_sec = nfs4_find_root_sec,
        .free_lock_state = nfs4_release_lockowner,
        .test_and_free_expired = nfs40_test_and_free_expired_stateid,
        .alloc_seqid = nfs_alloc_seqid,
        .call_sync_ops = &nfs40_call_sync_ops,
        .reboot_recovery_ops = &nfs40_reboot_recovery_ops,
        .nograce_recovery_ops = &nfs40_nograce_recovery_ops,
        .state_renewal_ops = &nfs40_state_renewal_ops,
        .mig_recovery_ops = &nfs40_mig_recovery_ops,
};

#if defined(CONFIG_NFS_V4_1)
static struct nfs_seqid *
nfs_alloc_no_seqid(struct nfs_seqid_counter *arg1, gfp_t arg2)
{
        return NULL;
}

static const struct nfs4_minor_version_ops nfs_v4_1_minor_ops = {
        .minor_version = 1,
        .init_caps = NFS_CAP_READDIRPLUS
                | NFS_CAP_ATOMIC_OPEN
                | NFS_CAP_POSIX_LOCK
                | NFS_CAP_STATEID_NFSV41
                | NFS_CAP_ATOMIC_OPEN_V1,
        .init_client = nfs41_init_client,
        .shutdown_client = nfs41_shutdown_client,
        .match_stateid = nfs41_match_stateid,
        .find_root_sec = nfs41_find_root_sec,
        .free_lock_state = nfs41_free_lock_state,
        .test_and_free_expired = nfs41_test_and_free_expired_stateid,
        .alloc_seqid = nfs_alloc_no_seqid,
        .session_trunk = nfs4_test_session_trunk,
        .call_sync_ops = &nfs41_call_sync_ops,
        .reboot_recovery_ops = &nfs41_reboot_recovery_ops,
        .nograce_recovery_ops = &nfs41_nograce_recovery_ops,
        .state_renewal_ops = &nfs41_state_renewal_ops,
        .mig_recovery_ops = &nfs41_mig_recovery_ops,
};
#endif

#if defined(CONFIG_NFS_V4_2)
static const struct nfs4_minor_version_ops nfs_v4_2_minor_ops = {
        .minor_version = 2,
        .init_caps = NFS_CAP_READDIRPLUS
                | NFS_CAP_ATOMIC_OPEN
                | NFS_CAP_POSIX_LOCK
                | NFS_CAP_STATEID_NFSV41
                | NFS_CAP_ATOMIC_OPEN_V1
                | NFS_CAP_ALLOCATE
                | NFS_CAP_COPY
                | NFS_CAP_DEALLOCATE
                | NFS_CAP_SEEK
                | NFS_CAP_LAYOUTSTATS
                | NFS_CAP_CLONE,
        .init_client = nfs41_init_client,
        .shutdown_client = nfs41_shutdown_client,
        .match_stateid = nfs41_match_stateid,
        .find_root_sec = nfs41_find_root_sec,
        .free_lock_state = nfs41_free_lock_state,
        .call_sync_ops = &nfs41_call_sync_ops,
        .test_and_free_expired = nfs41_test_and_free_expired_stateid,
        .alloc_seqid = nfs_alloc_no_seqid,
        .session_trunk = nfs4_test_session_trunk,
        .reboot_recovery_ops = &nfs41_reboot_recovery_ops,
        .nograce_recovery_ops = &nfs41_nograce_recovery_ops,
        .state_renewal_ops = &nfs41_state_renewal_ops,
        .mig_recovery_ops = &nfs41_mig_recovery_ops,
};
#endif

const struct nfs4_minor_version_ops *nfs_v4_minor_ops[] = {
        [0] = &nfs_v4_0_minor_ops,
#if defined(CONFIG_NFS_V4_1)
        [1] = &nfs_v4_1_minor_ops,
#endif
#if defined(CONFIG_NFS_V4_2)
        [2] = &nfs_v4_2_minor_ops,
#endif
};

static ssize_t nfs4_listxattr(struct dentry *dentry, char *list, size_t size)
{
        ssize_t error, error2;

        error = generic_listxattr(dentry, list, size);
        if (error < 0)
                return error;
        if (list) {
                list += error;
                size -= error;
        }

        error2 = nfs4_listxattr_nfs4_label(d_inode(dentry), list, size);
        if (error2 < 0)
                return error2;
        return error + error2;
}

static const struct inode_operations nfs4_dir_inode_operations = {
        .create         = nfs_create,
        .lookup         = nfs_lookup,
        .atomic_open    = nfs_atomic_open,
        .link           = nfs_link,
        .unlink         = nfs_unlink,
        .symlink        = nfs_symlink,
        .mkdir          = nfs_mkdir,
        .rmdir          = nfs_rmdir,
        .mknod          = nfs_mknod,
        .rename         = nfs_rename,
        .permission     = nfs_permission,
        .getattr        = nfs_getattr,
        .setattr        = nfs_setattr,
        .listxattr      = nfs4_listxattr,
};

static const struct inode_operations nfs4_file_inode_operations = {
        .permission     = nfs_permission,
        .getattr        = nfs_getattr,
        .setattr        = nfs_setattr,
        .listxattr      = nfs4_listxattr,
};

const struct nfs_rpc_ops nfs_v4_clientops = {
        .version        = 4,                    /* protocol version */
        .dentry_ops     = &nfs4_dentry_operations,
        .dir_inode_ops  = &nfs4_dir_inode_operations,
        .file_inode_ops = &nfs4_file_inode_operations,
        .file_ops       = &nfs4_file_operations,
        .getroot        = nfs4_proc_get_root,
        .submount       = nfs4_submount,
        .try_mount      = nfs4_try_mount,
        .getattr        = nfs4_proc_getattr,
        .setattr        = nfs4_proc_setattr,
        .lookup         = nfs4_proc_lookup,
        .lookupp        = nfs4_proc_lookupp,
        .access         = nfs4_proc_access,
        .readlink       = nfs4_proc_readlink,
        .create         = nfs4_proc_create,
        .remove         = nfs4_proc_remove,
        .unlink_setup   = nfs4_proc_unlink_setup,
        .unlink_rpc_prepare = nfs4_proc_unlink_rpc_prepare,
        .unlink_done    = nfs4_proc_unlink_done,
        .rename_setup   = nfs4_proc_rename_setup,
        .rename_rpc_prepare = nfs4_proc_rename_rpc_prepare,
        .rename_done    = nfs4_proc_rename_done,
        .link           = nfs4_proc_link,
        .symlink        = nfs4_proc_symlink,
        .mkdir          = nfs4_proc_mkdir,
        .rmdir          = nfs4_proc_remove,
        .readdir        = nfs4_proc_readdir,
        .mknod          = nfs4_proc_mknod,
        .statfs         = nfs4_proc_statfs,
        .fsinfo         = nfs4_proc_fsinfo,
        .pathconf       = nfs4_proc_pathconf,
        .set_capabilities = nfs4_server_capabilities,
        .decode_dirent  = nfs4_decode_dirent,
        .pgio_rpc_prepare = nfs4_proc_pgio_rpc_prepare,
        .read_setup     = nfs4_proc_read_setup,
        .read_done      = nfs4_read_done,
        .write_setup    = nfs4_proc_write_setup,
        .write_done     = nfs4_write_done,
        .commit_setup   = nfs4_proc_commit_setup,
        .commit_rpc_prepare = nfs4_proc_commit_rpc_prepare,
        .commit_done    = nfs4_commit_done,
        .lock           = nfs4_proc_lock,
        .clear_acl_cache = nfs4_zap_acl_attr,
        .close_context  = nfs4_close_context,
        .open_context   = nfs4_atomic_open,
        .have_delegation = nfs4_have_delegation,
        .return_delegation = nfs4_inode_return_delegation,
        .alloc_client   = nfs4_alloc_client,
        .init_client    = nfs4_init_client,
        .free_client    = nfs4_free_client,
        .create_server  = nfs4_create_server,
        .clone_server   = nfs_clone_server,
};

static const struct xattr_handler nfs4_xattr_nfs4_acl_handler = {
        .name   = XATTR_NAME_NFSV4_ACL,
        .list   = nfs4_xattr_list_nfs4_acl,
        .get    = nfs4_xattr_get_nfs4_acl,
        .set    = nfs4_xattr_set_nfs4_acl,
};

const struct xattr_handler *nfs4_xattr_handlers[] = {
        &nfs4_xattr_nfs4_acl_handler,
#ifdef CONFIG_NFS_V4_SECURITY_LABEL
        &nfs4_xattr_nfs4_label_handler,
#endif
        NULL
};

/*
 * Local variables:
 *  c-basic-offset: 8
 * End:
 */