e1000e: cleanup PARENTHESIS_ALIGNMENT checkpatch checks

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

/*
 *  pNFS Objects layout driver high level definitions
 *
 *  Copyright (C) 2007 Panasas Inc. [year of first publication]
 *  All rights reserved.
 *
 *  Benny Halevy <bhalevy@panasas.com>
 *  Boaz Harrosh <bharrosh@panasas.com>
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License version 2
 *  See the file COPYING included with this distribution for more details.
 *
 *  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 Panasas company 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/kmod.h>
#include <linux/moduleparam.h>
#include <linux/ratelimit.h>
#include <scsi/osd_initiator.h>
#include "objlayout.h"

#define NFSDBG_FACILITY         NFSDBG_PNFS_LD
/*
 * Create a objlayout layout structure for the given inode and return it.
 */
struct pnfs_layout_hdr *
objlayout_alloc_layout_hdr(struct inode *inode, gfp_t gfp_flags)
{
        struct objlayout *objlay;

        objlay = kzalloc(sizeof(struct objlayout), gfp_flags);
        if (objlay) {
                spin_lock_init(&objlay->lock);
                INIT_LIST_HEAD(&objlay->err_list);
        }
        dprintk("%s: Return %p\n", __func__, objlay);
        return &objlay->pnfs_layout;
}

/*
 * Free an objlayout layout structure
 */
void
objlayout_free_layout_hdr(struct pnfs_layout_hdr *lo)
{
        struct objlayout *objlay = OBJLAYOUT(lo);

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

        WARN_ON(!list_empty(&objlay->err_list));
        kfree(objlay);
}

/*
 * Unmarshall layout and store it in pnfslay.
 */
struct pnfs_layout_segment *
objlayout_alloc_lseg(struct pnfs_layout_hdr *pnfslay,
                     struct nfs4_layoutget_res *lgr,
                     gfp_t gfp_flags)
{
        int status = -ENOMEM;
        struct xdr_stream stream;
        struct xdr_buf buf = {
                .pages =  lgr->layoutp->pages,
                .page_len =  lgr->layoutp->len,
                .buflen =  lgr->layoutp->len,
                .len = lgr->layoutp->len,
        };
        struct page *scratch;
        struct pnfs_layout_segment *lseg;

        dprintk("%s: Begin pnfslay %p\n", __func__, pnfslay);

        scratch = alloc_page(gfp_flags);
        if (!scratch)
                goto err_nofree;

        xdr_init_decode(&stream, &buf, NULL);
        xdr_set_scratch_buffer(&stream, page_address(scratch), PAGE_SIZE);

        status = objio_alloc_lseg(&lseg, pnfslay, &lgr->range, &stream, gfp_flags);
        if (unlikely(status)) {
                dprintk("%s: objio_alloc_lseg Return err %d\n", __func__,
                        status);
                goto err;
        }

        __free_page(scratch);

        dprintk("%s: Return %p\n", __func__, lseg);
        return lseg;

err:
        __free_page(scratch);
err_nofree:
        dprintk("%s: Err Return=>%d\n", __func__, status);
        return ERR_PTR(status);
}

/*
 * Free a layout segement
 */
void
objlayout_free_lseg(struct pnfs_layout_segment *lseg)
{
        dprintk("%s: freeing layout segment %p\n", __func__, lseg);

        if (unlikely(!lseg))
                return;

        objio_free_lseg(lseg);
}

/*
 * I/O Operations
 */
static inline u64
end_offset(u64 start, u64 len)
{
        u64 end;

        end = start + len;
        return end >= start ? end : NFS4_MAX_UINT64;
}

static void _fix_verify_io_params(struct pnfs_layout_segment *lseg,
                           struct page ***p_pages, unsigned *p_pgbase,
                           u64 offset, unsigned long count)
{
        u64 lseg_end_offset;

        BUG_ON(offset < lseg->pls_range.offset);
        lseg_end_offset = end_offset(lseg->pls_range.offset,
                                     lseg->pls_range.length);
        BUG_ON(offset >= lseg_end_offset);
        WARN_ON(offset + count > lseg_end_offset);

        if (*p_pgbase > PAGE_SIZE) {
                dprintk("%s: pgbase(0x%x) > PAGE_SIZE\n", __func__, *p_pgbase);
                *p_pages += *p_pgbase >> PAGE_SHIFT;
                *p_pgbase &= ~PAGE_MASK;
        }
}

/*
 * I/O done common code
 */
static void
objlayout_iodone(struct objlayout_io_res *oir)
{
        if (likely(oir->status >= 0)) {
                objio_free_result(oir);
        } else {
                struct objlayout *objlay = oir->objlay;

                spin_lock(&objlay->lock);
                objlay->delta_space_valid = OBJ_DSU_INVALID;
                list_add(&objlay->err_list, &oir->err_list);
                spin_unlock(&objlay->lock);
        }
}

/*
 * objlayout_io_set_result - Set an osd_error code on a specific osd comp.
 *
 * The @index component IO failed (error returned from target). Register
 * the error for later reporting at layout-return.
 */
void
objlayout_io_set_result(struct objlayout_io_res *oir, unsigned index,
                        struct pnfs_osd_objid *pooid, int osd_error,
                        u64 offset, u64 length, bool is_write)
{
        struct pnfs_osd_ioerr *ioerr = &oir->ioerrs[index];

        BUG_ON(index >= oir->num_comps);
        if (osd_error) {
                ioerr->oer_component = *pooid;
                ioerr->oer_comp_offset = offset;
                ioerr->oer_comp_length = length;
                ioerr->oer_iswrite = is_write;
                ioerr->oer_errno = osd_error;

                dprintk("%s: err[%d]: errno=%d is_write=%d dev(%llx:%llx) "
                        "par=0x%llx obj=0x%llx offset=0x%llx length=0x%llx\n",
                        __func__, index, ioerr->oer_errno,
                        ioerr->oer_iswrite,
                        _DEVID_LO(&ioerr->oer_component.oid_device_id),
                        _DEVID_HI(&ioerr->oer_component.oid_device_id),
                        ioerr->oer_component.oid_partition_id,
                        ioerr->oer_component.oid_object_id,
                        ioerr->oer_comp_offset,
                        ioerr->oer_comp_length);
        } else {
                /* User need not call if no error is reported */
                ioerr->oer_errno = 0;
        }
}

/* Function scheduled on rpc workqueue to call ->nfs_readlist_complete().
 * This is because the osd completion is called with ints-off from
 * the block layer
 */
static void _rpc_read_complete(struct work_struct *work)
{
        struct rpc_task *task;
        struct nfs_read_data *rdata;

        dprintk("%s enter\n", __func__);
        task = container_of(work, struct rpc_task, u.tk_work);
        rdata = container_of(task, struct nfs_read_data, task);

        pnfs_ld_read_done(rdata);
}

void
objlayout_read_done(struct objlayout_io_res *oir, ssize_t status, bool sync)
{
        struct nfs_read_data *rdata = oir->rpcdata;

        oir->status = rdata->task.tk_status = status;
        if (status >= 0)
                rdata->res.count = status;
        else
                rdata->header->pnfs_error = status;
        objlayout_iodone(oir);
        /* must not use oir after this point */

        dprintk("%s: Return status=%zd eof=%d sync=%d\n", __func__,
                status, rdata->res.eof, sync);

        if (sync)
                pnfs_ld_read_done(rdata);
        else {
                INIT_WORK(&rdata->task.u.tk_work, _rpc_read_complete);
                schedule_work(&rdata->task.u.tk_work);
        }
}

/*
 * Perform sync or async reads.
 */
enum pnfs_try_status
objlayout_read_pagelist(struct nfs_read_data *rdata)
{
        struct nfs_pgio_header *hdr = rdata->header;
        struct inode *inode = hdr->inode;
        loff_t offset = rdata->args.offset;
        size_t count = rdata->args.count;
        int err;
        loff_t eof;

        eof = i_size_read(inode);
        if (unlikely(offset + count > eof)) {
                if (offset >= eof) {
                        err = 0;
                        rdata->res.count = 0;
                        rdata->res.eof = 1;
                        /*FIXME: do we need to call pnfs_ld_read_done() */
                        goto out;
                }
                count = eof - offset;
        }

        rdata->res.eof = (offset + count) >= eof;
        _fix_verify_io_params(hdr->lseg, &rdata->args.pages,
                              &rdata->args.pgbase,
                              rdata->args.offset, rdata->args.count);

        dprintk("%s: inode(%lx) offset 0x%llx count 0x%Zx eof=%d\n",
                __func__, inode->i_ino, offset, count, rdata->res.eof);

        err = objio_read_pagelist(rdata);
 out:
        if (unlikely(err)) {
                hdr->pnfs_error = err;
                dprintk("%s: Returned Error %d\n", __func__, err);
                return PNFS_NOT_ATTEMPTED;
        }
        return PNFS_ATTEMPTED;
}

/* Function scheduled on rpc workqueue to call ->nfs_writelist_complete().
 * This is because the osd completion is called with ints-off from
 * the block layer
 */
static void _rpc_write_complete(struct work_struct *work)
{
        struct rpc_task *task;
        struct nfs_write_data *wdata;

        dprintk("%s enter\n", __func__);
        task = container_of(work, struct rpc_task, u.tk_work);
        wdata = container_of(task, struct nfs_write_data, task);

        pnfs_ld_write_done(wdata);
}

void
objlayout_write_done(struct objlayout_io_res *oir, ssize_t status, bool sync)
{
        struct nfs_write_data *wdata = oir->rpcdata;

        oir->status = wdata->task.tk_status = status;
        if (status >= 0) {
                wdata->res.count = status;
                wdata->verf.committed = oir->committed;
        } else {
                wdata->header->pnfs_error = status;
        }
        objlayout_iodone(oir);
        /* must not use oir after this point */

        dprintk("%s: Return status %zd committed %d sync=%d\n", __func__,
                status, wdata->verf.committed, sync);

        if (sync)
                pnfs_ld_write_done(wdata);
        else {
                INIT_WORK(&wdata->task.u.tk_work, _rpc_write_complete);
                schedule_work(&wdata->task.u.tk_work);
        }
}

/*
 * Perform sync or async writes.
 */
enum pnfs_try_status
objlayout_write_pagelist(struct nfs_write_data *wdata,
                         int how)
{
        struct nfs_pgio_header *hdr = wdata->header;
        int err;

        _fix_verify_io_params(hdr->lseg, &wdata->args.pages,
                              &wdata->args.pgbase,
                              wdata->args.offset, wdata->args.count);

        err = objio_write_pagelist(wdata, how);
        if (unlikely(err)) {
                hdr->pnfs_error = err;
                dprintk("%s: Returned Error %d\n", __func__, err);
                return PNFS_NOT_ATTEMPTED;
        }
        return PNFS_ATTEMPTED;
}

void
objlayout_encode_layoutcommit(struct pnfs_layout_hdr *pnfslay,
                              struct xdr_stream *xdr,
                              const struct nfs4_layoutcommit_args *args)
{
        struct objlayout *objlay = OBJLAYOUT(pnfslay);
        struct pnfs_osd_layoutupdate lou;
        __be32 *start;

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

        spin_lock(&objlay->lock);
        lou.dsu_valid = (objlay->delta_space_valid == OBJ_DSU_VALID);
        lou.dsu_delta = objlay->delta_space_used;
        objlay->delta_space_used = 0;
        objlay->delta_space_valid = OBJ_DSU_INIT;
        lou.olu_ioerr_flag = !list_empty(&objlay->err_list);
        spin_unlock(&objlay->lock);

        start = xdr_reserve_space(xdr, 4);

        BUG_ON(pnfs_osd_xdr_encode_layoutupdate(xdr, &lou));

        *start = cpu_to_be32((xdr->p - start - 1) * 4);

        dprintk("%s: Return delta_space_used %lld err %d\n", __func__,
                lou.dsu_delta, lou.olu_ioerr_flag);
}

static int
err_prio(u32 oer_errno)
{
        switch (oer_errno) {
        case 0:
                return 0;

        case PNFS_OSD_ERR_RESOURCE:
                return OSD_ERR_PRI_RESOURCE;
        case PNFS_OSD_ERR_BAD_CRED:
                return OSD_ERR_PRI_BAD_CRED;
        case PNFS_OSD_ERR_NO_ACCESS:
                return OSD_ERR_PRI_NO_ACCESS;
        case PNFS_OSD_ERR_UNREACHABLE:
                return OSD_ERR_PRI_UNREACHABLE;
        case PNFS_OSD_ERR_NOT_FOUND:
                return OSD_ERR_PRI_NOT_FOUND;
        case PNFS_OSD_ERR_NO_SPACE:
                return OSD_ERR_PRI_NO_SPACE;
        default:
                WARN_ON(1);
                /* fallthrough */
        case PNFS_OSD_ERR_EIO:
                return OSD_ERR_PRI_EIO;
        }
}

static void
merge_ioerr(struct pnfs_osd_ioerr *dest_err,
            const struct pnfs_osd_ioerr *src_err)
{
        u64 dest_end, src_end;

        if (!dest_err->oer_errno) {
                *dest_err = *src_err;
                /* accumulated device must be blank */
                memset(&dest_err->oer_component.oid_device_id, 0,
                        sizeof(dest_err->oer_component.oid_device_id));

                return;
        }

        if (dest_err->oer_component.oid_partition_id !=
                                src_err->oer_component.oid_partition_id)
                dest_err->oer_component.oid_partition_id = 0;

        if (dest_err->oer_component.oid_object_id !=
                                src_err->oer_component.oid_object_id)
                dest_err->oer_component.oid_object_id = 0;

        if (dest_err->oer_comp_offset > src_err->oer_comp_offset)
                dest_err->oer_comp_offset = src_err->oer_comp_offset;

        dest_end = end_offset(dest_err->oer_comp_offset,
                              dest_err->oer_comp_length);
        src_end =  end_offset(src_err->oer_comp_offset,
                              src_err->oer_comp_length);
        if (dest_end < src_end)
                dest_end = src_end;

        dest_err->oer_comp_length = dest_end - dest_err->oer_comp_offset;

        if ((src_err->oer_iswrite == dest_err->oer_iswrite) &&
            (err_prio(src_err->oer_errno) > err_prio(dest_err->oer_errno))) {
                        dest_err->oer_errno = src_err->oer_errno;
        } else if (src_err->oer_iswrite) {
                dest_err->oer_iswrite = true;
                dest_err->oer_errno = src_err->oer_errno;
        }
}

static void
encode_accumulated_error(struct objlayout *objlay, __be32 *p)
{
        struct objlayout_io_res *oir, *tmp;
        struct pnfs_osd_ioerr accumulated_err = {.oer_errno = 0};

        list_for_each_entry_safe(oir, tmp, &objlay->err_list, err_list) {
                unsigned i;

                for (i = 0; i < oir->num_comps; i++) {
                        struct pnfs_osd_ioerr *ioerr = &oir->ioerrs[i];

                        if (!ioerr->oer_errno)
                                continue;

                        printk(KERN_ERR "NFS: %s: err[%d]: errno=%d "
                                "is_write=%d dev(%llx:%llx) par=0x%llx "
                                "obj=0x%llx offset=0x%llx length=0x%llx\n",
                                __func__, i, ioerr->oer_errno,
                                ioerr->oer_iswrite,
                                _DEVID_LO(&ioerr->oer_component.oid_device_id),
                                _DEVID_HI(&ioerr->oer_component.oid_device_id),
                                ioerr->oer_component.oid_partition_id,
                                ioerr->oer_component.oid_object_id,
                                ioerr->oer_comp_offset,
                                ioerr->oer_comp_length);

                        merge_ioerr(&accumulated_err, ioerr);
                }
                list_del(&oir->err_list);
                objio_free_result(oir);
        }

        pnfs_osd_xdr_encode_ioerr(p, &accumulated_err);
}

void
objlayout_encode_layoutreturn(struct pnfs_layout_hdr *pnfslay,
                              struct xdr_stream *xdr,
                              const struct nfs4_layoutreturn_args *args)
{
        struct objlayout *objlay = OBJLAYOUT(pnfslay);
        struct objlayout_io_res *oir, *tmp;
        __be32 *start;

        dprintk("%s: Begin\n", __func__);
        start = xdr_reserve_space(xdr, 4);
        BUG_ON(!start);

        spin_lock(&objlay->lock);

        list_for_each_entry_safe(oir, tmp, &objlay->err_list, err_list) {
                __be32 *last_xdr = NULL, *p;
                unsigned i;
                int res = 0;

                for (i = 0; i < oir->num_comps; i++) {
                        struct pnfs_osd_ioerr *ioerr = &oir->ioerrs[i];

                        if (!ioerr->oer_errno)
                                continue;

                        dprintk("%s: err[%d]: errno=%d is_write=%d "
                                "dev(%llx:%llx) par=0x%llx obj=0x%llx "
                                "offset=0x%llx length=0x%llx\n",
                                __func__, i, ioerr->oer_errno,
                                ioerr->oer_iswrite,
                                _DEVID_LO(&ioerr->oer_component.oid_device_id),
                                _DEVID_HI(&ioerr->oer_component.oid_device_id),
                                ioerr->oer_component.oid_partition_id,
                                ioerr->oer_component.oid_object_id,
                                ioerr->oer_comp_offset,
                                ioerr->oer_comp_length);

                        p = pnfs_osd_xdr_ioerr_reserve_space(xdr);
                        if (unlikely(!p)) {
                                res = -E2BIG;
                                break; /* accumulated_error */
                        }

                        last_xdr = p;
                        pnfs_osd_xdr_encode_ioerr(p, &oir->ioerrs[i]);
                }

                /* TODO: use xdr_write_pages */
                if (unlikely(res)) {
                        /* no space for even one error descriptor */
                        BUG_ON(!last_xdr);

                        /* we've encountered a situation with lots and lots of
                         * errors and no space to encode them all. Use the last
                         * available slot to report the union of all the
                         * remaining errors.
                         */
                        encode_accumulated_error(objlay, last_xdr);
                        goto loop_done;
                }
                list_del(&oir->err_list);
                objio_free_result(oir);
        }
loop_done:
        spin_unlock(&objlay->lock);

        *start = cpu_to_be32((xdr->p - start - 1) * 4);
        dprintk("%s: Return\n", __func__);
}


/*
 * Get Device Info API for io engines
 */
struct objlayout_deviceinfo {
        struct page *page;
        struct pnfs_osd_deviceaddr da; /* This must be last */
};

/* Initialize and call nfs_getdeviceinfo, then decode and return a
 * "struct pnfs_osd_deviceaddr *" Eventually objlayout_put_deviceinfo()
 * should be called.
 */
int objlayout_get_deviceinfo(struct pnfs_layout_hdr *pnfslay,
        struct nfs4_deviceid *d_id, struct pnfs_osd_deviceaddr **deviceaddr,
        gfp_t gfp_flags)
{
        struct objlayout_deviceinfo *odi;
        struct pnfs_device pd;
        struct page *page, **pages;
        u32 *p;
        int err;

        page = alloc_page(gfp_flags);
        if (!page)
                return -ENOMEM;

        pages = &page;
        pd.pages = pages;

        memcpy(&pd.dev_id, d_id, sizeof(*d_id));
        pd.layout_type = LAYOUT_OSD2_OBJECTS;
        pd.pages = &page;
        pd.pgbase = 0;
        pd.pglen = PAGE_SIZE;
        pd.mincount = 0;

        err = nfs4_proc_getdeviceinfo(NFS_SERVER(pnfslay->plh_inode), &pd);
        dprintk("%s nfs_getdeviceinfo returned %d\n", __func__, err);
        if (err)
                goto err_out;

        p = page_address(page);
        odi = kzalloc(sizeof(*odi), gfp_flags);
        if (!odi) {
                err = -ENOMEM;
                goto err_out;
        }
        pnfs_osd_xdr_decode_deviceaddr(&odi->da, p);
        odi->page = page;
        *deviceaddr = &odi->da;
        return 0;

err_out:
        __free_page(page);
        return err;
}

void objlayout_put_deviceinfo(struct pnfs_osd_deviceaddr *deviceaddr)
{
        struct objlayout_deviceinfo *odi = container_of(deviceaddr,
                                                struct objlayout_deviceinfo,
                                                da);

        __free_page(odi->page);
        kfree(odi);
}

enum {
        OBJLAYOUT_MAX_URI_LEN = 256, OBJLAYOUT_MAX_OSDNAME_LEN = 64,
        OBJLAYOUT_MAX_SYSID_HEX_LEN = OSD_SYSTEMID_LEN * 2 + 1,
        OSD_LOGIN_UPCALL_PATHLEN  = 256
};

static char osd_login_prog[OSD_LOGIN_UPCALL_PATHLEN] = "/sbin/osd_login";

module_param_string(osd_login_prog, osd_login_prog, sizeof(osd_login_prog),
                    0600);
MODULE_PARM_DESC(osd_login_prog, "Path to the osd_login upcall program");

struct __auto_login {
        char uri[OBJLAYOUT_MAX_URI_LEN];
        char osdname[OBJLAYOUT_MAX_OSDNAME_LEN];
        char systemid_hex[OBJLAYOUT_MAX_SYSID_HEX_LEN];
};

static int __objlayout_upcall(struct __auto_login *login)
{
        static char *envp[] = { "HOME=/",
                "TERM=linux",
                "PATH=/sbin:/usr/sbin:/bin:/usr/bin",
                NULL
        };
        char *argv[8];
        int ret;

        if (unlikely(!osd_login_prog[0])) {
                dprintk("%s: osd_login_prog is disabled\n", __func__);
                return -EACCES;
        }

        dprintk("%s uri: %s\n", __func__, login->uri);
        dprintk("%s osdname %s\n", __func__, login->osdname);
        dprintk("%s systemid_hex %s\n", __func__, login->systemid_hex);

        argv[0] = (char *)osd_login_prog;
        argv[1] = "-u";
        argv[2] = login->uri;
        argv[3] = "-o";
        argv[4] = login->osdname;
        argv[5] = "-s";
        argv[6] = login->systemid_hex;
        argv[7] = NULL;

        ret = call_usermodehelper(argv[0], argv, envp, UMH_WAIT_PROC);
        /*
         * Disable the upcall mechanism if we're getting an ENOENT or
         * EACCES error. The admin can re-enable it on the fly by using
         * sysfs to set the objlayoutdriver.osd_login_prog module parameter once
         * the problem has been fixed.
         */
        if (ret == -ENOENT || ret == -EACCES) {
                printk(KERN_ERR "PNFS-OBJ: %s was not found please set "
                        "objlayoutdriver.osd_login_prog kernel parameter!\n",
                        osd_login_prog);
                osd_login_prog[0] = '\0';
        }
        dprintk("%s %s return value: %d\n", __func__, osd_login_prog, ret);

        return ret;
}

/* Assume dest is all zeros */
static void __copy_nfsS_and_zero_terminate(struct nfs4_string s,
                                           char *dest, int max_len,
                                           const char *var_name)
{
        if (!s.len)
                return;

        if (s.len >= max_len) {
                pr_warn_ratelimited(
                        "objlayout_autologin: %s: s.len(%d) >= max_len(%d)",
                        var_name, s.len, max_len);
                s.len = max_len - 1; /* space for null terminator */
        }

        memcpy(dest, s.data, s.len);
}

/* Assume sysid is all zeros */
static void _sysid_2_hex(struct nfs4_string s,
                  char sysid[OBJLAYOUT_MAX_SYSID_HEX_LEN])
{
        int i;
        char *cur;

        if (!s.len)
                return;

        if (s.len != OSD_SYSTEMID_LEN) {
                pr_warn_ratelimited(
                    "objlayout_autologin: systemid_len(%d) != OSD_SYSTEMID_LEN",
                    s.len);
                if (s.len > OSD_SYSTEMID_LEN)
                        s.len = OSD_SYSTEMID_LEN;
        }

        cur = sysid;
        for (i = 0; i < s.len; i++)
                cur = hex_byte_pack(cur, s.data[i]);
}

int objlayout_autologin(struct pnfs_osd_deviceaddr *deviceaddr)
{
        int rc;
        struct __auto_login login;

        if (!deviceaddr->oda_targetaddr.ota_netaddr.r_addr.len)
                return -ENODEV;

        memset(&login, 0, sizeof(login));
        __copy_nfsS_and_zero_terminate(
                deviceaddr->oda_targetaddr.ota_netaddr.r_addr,
                login.uri, sizeof(login.uri), "URI");

        __copy_nfsS_and_zero_terminate(
                deviceaddr->oda_osdname,
                login.osdname, sizeof(login.osdname), "OSDNAME");

        _sysid_2_hex(deviceaddr->oda_systemid, login.systemid_hex);

        rc = __objlayout_upcall(&login);
        if (rc > 0) /* script returns positive values */
                rc = -ENODEV;

        return rc;
}