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

[linux/fpc-iii.git] / fs / ocfs2 / inode.c

/* -*- mode: c; c-basic-offset: 8; -*-
 * vim: noexpandtab sw=8 ts=8 sts=0:
 *
 * inode.c
 *
 * vfs' aops, fops, dops and iops
 *
 * Copyright (C) 2002, 2004 Oracle.  All rights reserved.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public
 * License along with this program; if not, write to the
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA 021110-1307, USA.
 */

#include <linux/fs.h>
#include <linux/types.h>
#include <linux/highmem.h>
#include <linux/pagemap.h>
#include <linux/quotaops.h>

#include <asm/byteorder.h>

#include <cluster/masklog.h>

#include "ocfs2.h"

#include "alloc.h"
#include "dir.h"
#include "blockcheck.h"
#include "dlmglue.h"
#include "extent_map.h"
#include "file.h"
#include "heartbeat.h"
#include "inode.h"
#include "journal.h"
#include "namei.h"
#include "suballoc.h"
#include "super.h"
#include "symlink.h"
#include "sysfile.h"
#include "uptodate.h"
#include "xattr.h"
#include "refcounttree.h"
#include "ocfs2_trace.h"
#include "filecheck.h"

#include "buffer_head_io.h"

struct ocfs2_find_inode_args
{
        u64             fi_blkno;
        unsigned long   fi_ino;
        unsigned int    fi_flags;
        unsigned int    fi_sysfile_type;
};

static struct lock_class_key ocfs2_sysfile_lock_key[NUM_SYSTEM_INODES];

static int ocfs2_read_locked_inode(struct inode *inode,
                                   struct ocfs2_find_inode_args *args);
static int ocfs2_init_locked_inode(struct inode *inode, void *opaque);
static int ocfs2_find_actor(struct inode *inode, void *opaque);
static int ocfs2_truncate_for_delete(struct ocfs2_super *osb,
                                    struct inode *inode,
                                    struct buffer_head *fe_bh);

static int ocfs2_filecheck_read_inode_block_full(struct inode *inode,
                                                 struct buffer_head **bh,
                                                 int flags, int type);
static int ocfs2_filecheck_validate_inode_block(struct super_block *sb,
                                                struct buffer_head *bh);
static int ocfs2_filecheck_repair_inode_block(struct super_block *sb,
                                              struct buffer_head *bh);

void ocfs2_set_inode_flags(struct inode *inode)
{
        unsigned int flags = OCFS2_I(inode)->ip_attr;

        inode->i_flags &= ~(S_IMMUTABLE |
                S_SYNC | S_APPEND | S_NOATIME | S_DIRSYNC);

        if (flags & OCFS2_IMMUTABLE_FL)
                inode->i_flags |= S_IMMUTABLE;

        if (flags & OCFS2_SYNC_FL)
                inode->i_flags |= S_SYNC;
        if (flags & OCFS2_APPEND_FL)
                inode->i_flags |= S_APPEND;
        if (flags & OCFS2_NOATIME_FL)
                inode->i_flags |= S_NOATIME;
        if (flags & OCFS2_DIRSYNC_FL)
                inode->i_flags |= S_DIRSYNC;
}

/* Propagate flags from i_flags to OCFS2_I(inode)->ip_attr */
void ocfs2_get_inode_flags(struct ocfs2_inode_info *oi)
{
        unsigned int flags = oi->vfs_inode.i_flags;

        oi->ip_attr &= ~(OCFS2_SYNC_FL|OCFS2_APPEND_FL|
                        OCFS2_IMMUTABLE_FL|OCFS2_NOATIME_FL|OCFS2_DIRSYNC_FL);
        if (flags & S_SYNC)
                oi->ip_attr |= OCFS2_SYNC_FL;
        if (flags & S_APPEND)
                oi->ip_attr |= OCFS2_APPEND_FL;
        if (flags & S_IMMUTABLE)
                oi->ip_attr |= OCFS2_IMMUTABLE_FL;
        if (flags & S_NOATIME)
                oi->ip_attr |= OCFS2_NOATIME_FL;
        if (flags & S_DIRSYNC)
                oi->ip_attr |= OCFS2_DIRSYNC_FL;
}

struct inode *ocfs2_ilookup(struct super_block *sb, u64 blkno)
{
        struct ocfs2_find_inode_args args;

        args.fi_blkno = blkno;
        args.fi_flags = 0;
        args.fi_ino = ino_from_blkno(sb, blkno);
        args.fi_sysfile_type = 0;

        return ilookup5(sb, blkno, ocfs2_find_actor, &args);
}
struct inode *ocfs2_iget(struct ocfs2_super *osb, u64 blkno, unsigned flags,
                         int sysfile_type)
{
        int rc = -ESTALE;
        struct inode *inode = NULL;
        struct super_block *sb = osb->sb;
        struct ocfs2_find_inode_args args;
        journal_t *journal = OCFS2_SB(sb)->journal->j_journal;

        trace_ocfs2_iget_begin((unsigned long long)blkno, flags,
                               sysfile_type);

        /* Ok. By now we've either got the offsets passed to us by the
         * caller, or we just pulled them off the bh. Lets do some
         * sanity checks to make sure they're OK. */
        if (blkno == 0) {
                inode = ERR_PTR(-EINVAL);
                mlog_errno(PTR_ERR(inode));
                goto bail;
        }

        args.fi_blkno = blkno;
        args.fi_flags = flags;
        args.fi_ino = ino_from_blkno(sb, blkno);
        args.fi_sysfile_type = sysfile_type;

        inode = iget5_locked(sb, args.fi_ino, ocfs2_find_actor,
                             ocfs2_init_locked_inode, &args);
        /* inode was *not* in the inode cache. 2.6.x requires
         * us to do our own read_inode call and unlock it
         * afterwards. */
        if (inode == NULL) {
                inode = ERR_PTR(-ENOMEM);
                mlog_errno(PTR_ERR(inode));
                goto bail;
        }
        trace_ocfs2_iget5_locked(inode->i_state);
        if (inode->i_state & I_NEW) {
                rc = ocfs2_read_locked_inode(inode, &args);
                unlock_new_inode(inode);
        }
        if (is_bad_inode(inode)) {
                iput(inode);
                inode = ERR_PTR(rc);
                goto bail;
        }

        /*
         * Set transaction id's of transactions that have to be committed
         * to finish f[data]sync. We set them to currently running transaction
         * as we cannot be sure that the inode or some of its metadata isn't
         * part of the transaction - the inode could have been reclaimed and
         * now it is reread from disk.
         */
        if (journal) {
                transaction_t *transaction;
                tid_t tid;
                struct ocfs2_inode_info *oi = OCFS2_I(inode);

                read_lock(&journal->j_state_lock);
                if (journal->j_running_transaction)
                        transaction = journal->j_running_transaction;
                else
                        transaction = journal->j_committing_transaction;
                if (transaction)
                        tid = transaction->t_tid;
                else
                        tid = journal->j_commit_sequence;
                read_unlock(&journal->j_state_lock);
                oi->i_sync_tid = tid;
                oi->i_datasync_tid = tid;
        }

bail:
        if (!IS_ERR(inode)) {
                trace_ocfs2_iget_end(inode, 
                        (unsigned long long)OCFS2_I(inode)->ip_blkno);
        }

        return inode;
}


/*
 * here's how inodes get read from disk:
 * iget5_locked -> find_actor -> OCFS2_FIND_ACTOR
 * found? : return the in-memory inode
 * not found? : get_new_inode -> OCFS2_INIT_LOCKED_INODE
 */

static int ocfs2_find_actor(struct inode *inode, void *opaque)
{
        struct ocfs2_find_inode_args *args = NULL;
        struct ocfs2_inode_info *oi = OCFS2_I(inode);
        int ret = 0;

        args = opaque;

        mlog_bug_on_msg(!inode, "No inode in find actor!\n");

        trace_ocfs2_find_actor(inode, inode->i_ino, opaque, args->fi_blkno);

        if (oi->ip_blkno != args->fi_blkno)
                goto bail;

        ret = 1;
bail:
        return ret;
}

/*
 * initialize the new inode, but don't do anything that would cause
 * us to sleep.
 * return 0 on success, 1 on failure
 */
static int ocfs2_init_locked_inode(struct inode *inode, void *opaque)
{
        struct ocfs2_find_inode_args *args = opaque;
        static struct lock_class_key ocfs2_quota_ip_alloc_sem_key,
                                     ocfs2_file_ip_alloc_sem_key;

        inode->i_ino = args->fi_ino;
        OCFS2_I(inode)->ip_blkno = args->fi_blkno;
        if (args->fi_sysfile_type != 0)
                lockdep_set_class(&inode->i_rwsem,
                        &ocfs2_sysfile_lock_key[args->fi_sysfile_type]);
        if (args->fi_sysfile_type == USER_QUOTA_SYSTEM_INODE ||
            args->fi_sysfile_type == GROUP_QUOTA_SYSTEM_INODE ||
            args->fi_sysfile_type == LOCAL_USER_QUOTA_SYSTEM_INODE ||
            args->fi_sysfile_type == LOCAL_GROUP_QUOTA_SYSTEM_INODE)
                lockdep_set_class(&OCFS2_I(inode)->ip_alloc_sem,
                                  &ocfs2_quota_ip_alloc_sem_key);
        else
                lockdep_set_class(&OCFS2_I(inode)->ip_alloc_sem,
                                  &ocfs2_file_ip_alloc_sem_key);

        return 0;
}

void ocfs2_populate_inode(struct inode *inode, struct ocfs2_dinode *fe,
                          int create_ino)
{
        struct super_block *sb;
        struct ocfs2_super *osb;
        int use_plocks = 1;

        sb = inode->i_sb;
        osb = OCFS2_SB(sb);

        if ((osb->s_mount_opt & OCFS2_MOUNT_LOCALFLOCKS) ||
            ocfs2_mount_local(osb) || !ocfs2_stack_supports_plocks())
                use_plocks = 0;

        /*
         * These have all been checked by ocfs2_read_inode_block() or set
         * by ocfs2_mknod_locked(), so a failure is a code bug.
         */
        BUG_ON(!OCFS2_IS_VALID_DINODE(fe));  /* This means that read_inode
                                                cannot create a superblock
                                                inode today.  change if
                                                that is needed. */
        BUG_ON(!(fe->i_flags & cpu_to_le32(OCFS2_VALID_FL)));
        BUG_ON(le32_to_cpu(fe->i_fs_generation) != osb->fs_generation);


        OCFS2_I(inode)->ip_clusters = le32_to_cpu(fe->i_clusters);
        OCFS2_I(inode)->ip_attr = le32_to_cpu(fe->i_attr);
        OCFS2_I(inode)->ip_dyn_features = le16_to_cpu(fe->i_dyn_features);

        inode->i_version = 1;
        inode->i_generation = le32_to_cpu(fe->i_generation);
        inode->i_rdev = huge_decode_dev(le64_to_cpu(fe->id1.dev1.i_rdev));
        inode->i_mode = le16_to_cpu(fe->i_mode);
        i_uid_write(inode, le32_to_cpu(fe->i_uid));
        i_gid_write(inode, le32_to_cpu(fe->i_gid));

        /* Fast symlinks will have i_size but no allocated clusters. */
        if (S_ISLNK(inode->i_mode) && !fe->i_clusters) {
                inode->i_blocks = 0;
                inode->i_mapping->a_ops = &ocfs2_fast_symlink_aops;
        } else {
                inode->i_blocks = ocfs2_inode_sector_count(inode);
                inode->i_mapping->a_ops = &ocfs2_aops;
        }
        inode->i_atime.tv_sec = le64_to_cpu(fe->i_atime);
        inode->i_atime.tv_nsec = le32_to_cpu(fe->i_atime_nsec);
        inode->i_mtime.tv_sec = le64_to_cpu(fe->i_mtime);
        inode->i_mtime.tv_nsec = le32_to_cpu(fe->i_mtime_nsec);
        inode->i_ctime.tv_sec = le64_to_cpu(fe->i_ctime);
        inode->i_ctime.tv_nsec = le32_to_cpu(fe->i_ctime_nsec);

        if (OCFS2_I(inode)->ip_blkno != le64_to_cpu(fe->i_blkno))
                mlog(ML_ERROR,
                     "ip_blkno %llu != i_blkno %llu!\n",
                     (unsigned long long)OCFS2_I(inode)->ip_blkno,
                     (unsigned long long)le64_to_cpu(fe->i_blkno));

        set_nlink(inode, ocfs2_read_links_count(fe));

        trace_ocfs2_populate_inode(OCFS2_I(inode)->ip_blkno,
                                   le32_to_cpu(fe->i_flags));
        if (fe->i_flags & cpu_to_le32(OCFS2_SYSTEM_FL)) {
                OCFS2_I(inode)->ip_flags |= OCFS2_INODE_SYSTEM_FILE;
                inode->i_flags |= S_NOQUOTA;
        }
  
        if (fe->i_flags & cpu_to_le32(OCFS2_LOCAL_ALLOC_FL)) {
                OCFS2_I(inode)->ip_flags |= OCFS2_INODE_BITMAP;
        } else if (fe->i_flags & cpu_to_le32(OCFS2_BITMAP_FL)) {
                OCFS2_I(inode)->ip_flags |= OCFS2_INODE_BITMAP;
        } else if (fe->i_flags & cpu_to_le32(OCFS2_QUOTA_FL)) {
                inode->i_flags |= S_NOQUOTA;
        } else if (fe->i_flags & cpu_to_le32(OCFS2_SUPER_BLOCK_FL)) {
                /* we can't actually hit this as read_inode can't
                 * handle superblocks today ;-) */
                BUG();
        }

        switch (inode->i_mode & S_IFMT) {
            case S_IFREG:
                    if (use_plocks)
                            inode->i_fop = &ocfs2_fops;
                    else
                            inode->i_fop = &ocfs2_fops_no_plocks;
                    inode->i_op = &ocfs2_file_iops;
                    i_size_write(inode, le64_to_cpu(fe->i_size));
                    break;
            case S_IFDIR:
                    inode->i_op = &ocfs2_dir_iops;
                    if (use_plocks)
                            inode->i_fop = &ocfs2_dops;
                    else
                            inode->i_fop = &ocfs2_dops_no_plocks;
                    i_size_write(inode, le64_to_cpu(fe->i_size));
                    OCFS2_I(inode)->ip_dir_lock_gen = 1;
                    break;
            case S_IFLNK:
                    inode->i_op = &ocfs2_symlink_inode_operations;
                    inode_nohighmem(inode);
                    i_size_write(inode, le64_to_cpu(fe->i_size));
                    break;
            default:
                    inode->i_op = &ocfs2_special_file_iops;
                    init_special_inode(inode, inode->i_mode,
                                       inode->i_rdev);
                    break;
        }

        if (create_ino) {
                inode->i_ino = ino_from_blkno(inode->i_sb,
                               le64_to_cpu(fe->i_blkno));

                /*
                 * If we ever want to create system files from kernel,
                 * the generation argument to
                 * ocfs2_inode_lock_res_init() will have to change.
                 */
                BUG_ON(le32_to_cpu(fe->i_flags) & OCFS2_SYSTEM_FL);

                ocfs2_inode_lock_res_init(&OCFS2_I(inode)->ip_inode_lockres,
                                          OCFS2_LOCK_TYPE_META, 0, inode);

                ocfs2_inode_lock_res_init(&OCFS2_I(inode)->ip_open_lockres,
                                          OCFS2_LOCK_TYPE_OPEN, 0, inode);
        }

        ocfs2_inode_lock_res_init(&OCFS2_I(inode)->ip_rw_lockres,
                                  OCFS2_LOCK_TYPE_RW, inode->i_generation,
                                  inode);

        ocfs2_set_inode_flags(inode);

        OCFS2_I(inode)->ip_last_used_slot = 0;
        OCFS2_I(inode)->ip_last_used_group = 0;

        if (S_ISDIR(inode->i_mode))
                ocfs2_resv_set_type(&OCFS2_I(inode)->ip_la_data_resv,
                                    OCFS2_RESV_FLAG_DIR);
}

static int ocfs2_read_locked_inode(struct inode *inode,
                                   struct ocfs2_find_inode_args *args)
{
        struct super_block *sb;
        struct ocfs2_super *osb;
        struct ocfs2_dinode *fe;
        struct buffer_head *bh = NULL;
        int status, can_lock, lock_level = 0;
        u32 generation = 0;

        status = -EINVAL;
        sb = inode->i_sb;
        osb = OCFS2_SB(sb);

        /*
         * To improve performance of cold-cache inode stats, we take
         * the cluster lock here if possible.
         *
         * Generally, OCFS2 never trusts the contents of an inode
         * unless it's holding a cluster lock, so taking it here isn't
         * a correctness issue as much as it is a performance
         * improvement.
         *
         * There are three times when taking the lock is not a good idea:
         *
         * 1) During startup, before we have initialized the DLM.
         *
         * 2) If we are reading certain system files which never get
         *    cluster locks (local alloc, truncate log).
         *
         * 3) If the process doing the iget() is responsible for
         *    orphan dir recovery. We're holding the orphan dir lock and
         *    can get into a deadlock with another process on another
         *    node in ->delete_inode().
         *
         * #1 and #2 can be simply solved by never taking the lock
         * here for system files (which are the only type we read
         * during mount). It's a heavier approach, but our main
         * concern is user-accessible files anyway.
         *
         * #3 works itself out because we'll eventually take the
         * cluster lock before trusting anything anyway.
         */
        can_lock = !(args->fi_flags & OCFS2_FI_FLAG_SYSFILE)
                && !(args->fi_flags & OCFS2_FI_FLAG_ORPHAN_RECOVERY)
                && !ocfs2_mount_local(osb);

        trace_ocfs2_read_locked_inode(
                (unsigned long long)OCFS2_I(inode)->ip_blkno, can_lock);

        /*
         * To maintain backwards compatibility with older versions of
         * ocfs2-tools, we still store the generation value for system
         * files. The only ones that actually matter to userspace are
         * the journals, but it's easier and inexpensive to just flag
         * all system files similarly.
         */
        if (args->fi_flags & OCFS2_FI_FLAG_SYSFILE)
                generation = osb->fs_generation;

        ocfs2_inode_lock_res_init(&OCFS2_I(inode)->ip_inode_lockres,
                                  OCFS2_LOCK_TYPE_META,
                                  generation, inode);

        ocfs2_inode_lock_res_init(&OCFS2_I(inode)->ip_open_lockres,
                                  OCFS2_LOCK_TYPE_OPEN,
                                  0, inode);

        if (can_lock) {
                status = ocfs2_open_lock(inode);
                if (status) {
                        make_bad_inode(inode);
                        mlog_errno(status);
                        return status;
                }
                status = ocfs2_inode_lock(inode, NULL, lock_level);
                if (status) {
                        make_bad_inode(inode);
                        mlog_errno(status);
                        return status;
                }
        }

        if (args->fi_flags & OCFS2_FI_FLAG_ORPHAN_RECOVERY) {
                status = ocfs2_try_open_lock(inode, 0);
                if (status) {
                        make_bad_inode(inode);
                        return status;
                }
        }

        if (can_lock) {
                if (args->fi_flags & OCFS2_FI_FLAG_FILECHECK_CHK)
                        status = ocfs2_filecheck_read_inode_block_full(inode,
                                                &bh, OCFS2_BH_IGNORE_CACHE, 0);
                else if (args->fi_flags & OCFS2_FI_FLAG_FILECHECK_FIX)
                        status = ocfs2_filecheck_read_inode_block_full(inode,
                                                &bh, OCFS2_BH_IGNORE_CACHE, 1);
                else
                        status = ocfs2_read_inode_block_full(inode,
                                                &bh, OCFS2_BH_IGNORE_CACHE);
        } else {
                status = ocfs2_read_blocks_sync(osb, args->fi_blkno, 1, &bh);
                /*
                 * If buffer is in jbd, then its checksum may not have been
                 * computed as yet.
                 */
                if (!status && !buffer_jbd(bh)) {
                        if (args->fi_flags & OCFS2_FI_FLAG_FILECHECK_CHK)
                                status = ocfs2_filecheck_validate_inode_block(
                                                                osb->sb, bh);
                        else if (args->fi_flags & OCFS2_FI_FLAG_FILECHECK_FIX)
                                status = ocfs2_filecheck_repair_inode_block(
                                                                osb->sb, bh);
                        else
                                status = ocfs2_validate_inode_block(
                                                                osb->sb, bh);
                }
        }
        if (status < 0) {
                mlog_errno(status);
                goto bail;
        }

        status = -EINVAL;
        fe = (struct ocfs2_dinode *) bh->b_data;

        /*
         * This is a code bug. Right now the caller needs to
         * understand whether it is asking for a system file inode or
         * not so the proper lock names can be built.
         */
        mlog_bug_on_msg(!!(fe->i_flags & cpu_to_le32(OCFS2_SYSTEM_FL)) !=
                        !!(args->fi_flags & OCFS2_FI_FLAG_SYSFILE),
                        "Inode %llu: system file state is ambigous\n",
                        (unsigned long long)args->fi_blkno);

        if (S_ISCHR(le16_to_cpu(fe->i_mode)) ||
            S_ISBLK(le16_to_cpu(fe->i_mode)))
                inode->i_rdev = huge_decode_dev(le64_to_cpu(fe->id1.dev1.i_rdev));

        ocfs2_populate_inode(inode, fe, 0);

        BUG_ON(args->fi_blkno != le64_to_cpu(fe->i_blkno));

        if (buffer_dirty(bh) && !buffer_jbd(bh)) {
                if (can_lock) {
                        ocfs2_inode_unlock(inode, lock_level);
                        lock_level = 1;
                        ocfs2_inode_lock(inode, NULL, lock_level);
                }
                status = ocfs2_write_block(osb, bh, INODE_CACHE(inode));
                if (status < 0) {
                        mlog_errno(status);
                        goto bail;
                }
        }

        status = 0;

bail:
        if (can_lock)
                ocfs2_inode_unlock(inode, lock_level);

        if (status < 0)
                make_bad_inode(inode);

        brelse(bh);

        return status;
}

void ocfs2_sync_blockdev(struct super_block *sb)
{
        sync_blockdev(sb->s_bdev);
}

static int ocfs2_truncate_for_delete(struct ocfs2_super *osb,
                                     struct inode *inode,
                                     struct buffer_head *fe_bh)
{
        int status = 0;
        struct ocfs2_dinode *fe;
        handle_t *handle = NULL;

        fe = (struct ocfs2_dinode *) fe_bh->b_data;

        /*
         * This check will also skip truncate of inodes with inline
         * data and fast symlinks.
         */
        if (fe->i_clusters) {
                if (ocfs2_should_order_data(inode))
                        ocfs2_begin_ordered_truncate(inode, 0);

                handle = ocfs2_start_trans(osb, OCFS2_INODE_UPDATE_CREDITS);
                if (IS_ERR(handle)) {
                        status = PTR_ERR(handle);
                        handle = NULL;
                        mlog_errno(status);
                        goto out;
                }

                status = ocfs2_journal_access_di(handle, INODE_CACHE(inode),
                                                 fe_bh,
                                                 OCFS2_JOURNAL_ACCESS_WRITE);
                if (status < 0) {
                        mlog_errno(status);
                        goto out;
                }

                i_size_write(inode, 0);

                status = ocfs2_mark_inode_dirty(handle, inode, fe_bh);
                if (status < 0) {
                        mlog_errno(status);
                        goto out;
                }

                ocfs2_commit_trans(osb, handle);
                handle = NULL;

                status = ocfs2_commit_truncate(osb, inode, fe_bh);
                if (status < 0) {
                        mlog_errno(status);
                        goto out;
                }
        }

out:
        if (handle)
                ocfs2_commit_trans(osb, handle);
        return status;
}

static int ocfs2_remove_inode(struct inode *inode,
                              struct buffer_head *di_bh,
                              struct inode *orphan_dir_inode,
                              struct buffer_head *orphan_dir_bh)
{
        int status;
        struct inode *inode_alloc_inode = NULL;
        struct buffer_head *inode_alloc_bh = NULL;
        handle_t *handle;
        struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
        struct ocfs2_dinode *di = (struct ocfs2_dinode *) di_bh->b_data;

        inode_alloc_inode =
                ocfs2_get_system_file_inode(osb, INODE_ALLOC_SYSTEM_INODE,
                                            le16_to_cpu(di->i_suballoc_slot));
        if (!inode_alloc_inode) {
                status = -ENOENT;
                mlog_errno(status);
                goto bail;
        }

        inode_lock(inode_alloc_inode);
        status = ocfs2_inode_lock(inode_alloc_inode, &inode_alloc_bh, 1);
        if (status < 0) {
                inode_unlock(inode_alloc_inode);

                mlog_errno(status);
                goto bail;
        }

        handle = ocfs2_start_trans(osb, OCFS2_DELETE_INODE_CREDITS +
                                   ocfs2_quota_trans_credits(inode->i_sb));
        if (IS_ERR(handle)) {
                status = PTR_ERR(handle);
                mlog_errno(status);
                goto bail_unlock;
        }

        if (!(OCFS2_I(inode)->ip_flags & OCFS2_INODE_SKIP_ORPHAN_DIR)) {
                status = ocfs2_orphan_del(osb, handle, orphan_dir_inode, inode,
                                          orphan_dir_bh, false);
                if (status < 0) {
                        mlog_errno(status);
                        goto bail_commit;
                }
        }

        /* set the inodes dtime */
        status = ocfs2_journal_access_di(handle, INODE_CACHE(inode), di_bh,
                                         OCFS2_JOURNAL_ACCESS_WRITE);
        if (status < 0) {
                mlog_errno(status);
                goto bail_commit;
        }

        di->i_dtime = cpu_to_le64(ktime_get_real_seconds());
        di->i_flags &= cpu_to_le32(~(OCFS2_VALID_FL | OCFS2_ORPHANED_FL));
        ocfs2_journal_dirty(handle, di_bh);

        ocfs2_remove_from_cache(INODE_CACHE(inode), di_bh);
        dquot_free_inode(inode);

        status = ocfs2_free_dinode(handle, inode_alloc_inode,
                                   inode_alloc_bh, di);
        if (status < 0)
                mlog_errno(status);

bail_commit:
        ocfs2_commit_trans(osb, handle);
bail_unlock:
        ocfs2_inode_unlock(inode_alloc_inode, 1);
        inode_unlock(inode_alloc_inode);
        brelse(inode_alloc_bh);
bail:
        iput(inode_alloc_inode);

        return status;
}

/*
 * Serialize with orphan dir recovery. If the process doing
 * recovery on this orphan dir does an iget() with the dir
 * i_mutex held, we'll deadlock here. Instead we detect this
 * and exit early - recovery will wipe this inode for us.
 */
static int ocfs2_check_orphan_recovery_state(struct ocfs2_super *osb,
                                             int slot)
{
        int ret = 0;

        spin_lock(&osb->osb_lock);
        if (ocfs2_node_map_test_bit(osb, &osb->osb_recovering_orphan_dirs, slot)) {
                ret = -EDEADLK;
                goto out;
        }
        /* This signals to the orphan recovery process that it should
         * wait for us to handle the wipe. */
        osb->osb_orphan_wipes[slot]++;
out:
        spin_unlock(&osb->osb_lock);
        trace_ocfs2_check_orphan_recovery_state(slot, ret);
        return ret;
}

static void ocfs2_signal_wipe_completion(struct ocfs2_super *osb,
                                         int slot)
{
        spin_lock(&osb->osb_lock);
        osb->osb_orphan_wipes[slot]--;
        spin_unlock(&osb->osb_lock);

        wake_up(&osb->osb_wipe_event);
}

static int ocfs2_wipe_inode(struct inode *inode,
                            struct buffer_head *di_bh)
{
        int status, orphaned_slot = -1;
        struct inode *orphan_dir_inode = NULL;
        struct buffer_head *orphan_dir_bh = NULL;
        struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
        struct ocfs2_dinode *di = (struct ocfs2_dinode *) di_bh->b_data;

        if (!(OCFS2_I(inode)->ip_flags & OCFS2_INODE_SKIP_ORPHAN_DIR)) {
                orphaned_slot = le16_to_cpu(di->i_orphaned_slot);

                status = ocfs2_check_orphan_recovery_state(osb, orphaned_slot);
                if (status)
                        return status;

                orphan_dir_inode = ocfs2_get_system_file_inode(osb,
                                                               ORPHAN_DIR_SYSTEM_INODE,
                                                               orphaned_slot);
                if (!orphan_dir_inode) {
                        status = -ENOENT;
                        mlog_errno(status);
                        goto bail;
                }

                /* Lock the orphan dir. The lock will be held for the entire
                 * delete_inode operation. We do this now to avoid races with
                 * recovery completion on other nodes. */
                inode_lock(orphan_dir_inode);
                status = ocfs2_inode_lock(orphan_dir_inode, &orphan_dir_bh, 1);
                if (status < 0) {
                        inode_unlock(orphan_dir_inode);

                        mlog_errno(status);
                        goto bail;
                }
        }

        /* we do this while holding the orphan dir lock because we
         * don't want recovery being run from another node to try an
         * inode delete underneath us -- this will result in two nodes
         * truncating the same file! */
        status = ocfs2_truncate_for_delete(osb, inode, di_bh);
        if (status < 0) {
                mlog_errno(status);
                goto bail_unlock_dir;
        }

        /* Remove any dir index tree */
        if (S_ISDIR(inode->i_mode)) {
                status = ocfs2_dx_dir_truncate(inode, di_bh);
                if (status) {
                        mlog_errno(status);
                        goto bail_unlock_dir;
                }
        }

        /*Free extended attribute resources associated with this inode.*/
        status = ocfs2_xattr_remove(inode, di_bh);
        if (status < 0) {
                mlog_errno(status);
                goto bail_unlock_dir;
        }

        status = ocfs2_remove_refcount_tree(inode, di_bh);
        if (status < 0) {
                mlog_errno(status);
                goto bail_unlock_dir;
        }

        status = ocfs2_remove_inode(inode, di_bh, orphan_dir_inode,
                                    orphan_dir_bh);
        if (status < 0)
                mlog_errno(status);

bail_unlock_dir:
        if (OCFS2_I(inode)->ip_flags & OCFS2_INODE_SKIP_ORPHAN_DIR)
                return status;

        ocfs2_inode_unlock(orphan_dir_inode, 1);
        inode_unlock(orphan_dir_inode);
        brelse(orphan_dir_bh);
bail:
        iput(orphan_dir_inode);
        ocfs2_signal_wipe_completion(osb, orphaned_slot);

        return status;
}

/* There is a series of simple checks that should be done before a
 * trylock is even considered. Encapsulate those in this function. */
static int ocfs2_inode_is_valid_to_delete(struct inode *inode)
{
        int ret = 0;
        struct ocfs2_inode_info *oi = OCFS2_I(inode);
        struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);

        trace_ocfs2_inode_is_valid_to_delete(current, osb->dc_task,
                                             (unsigned long long)oi->ip_blkno,
                                             oi->ip_flags);

        /* We shouldn't be getting here for the root directory
         * inode.. */
        if (inode == osb->root_inode) {
                mlog(ML_ERROR, "Skipping delete of root inode.\n");
                goto bail;
        }

        /*
         * If we're coming from downconvert_thread we can't go into our own
         * voting [hello, deadlock city!] so we cannot delete the inode. But
         * since we dropped last inode ref when downconverting dentry lock,
         * we cannot have the file open and thus the node doing unlink will
         * take care of deleting the inode.
         */
        if (current == osb->dc_task)
                goto bail;

        spin_lock(&oi->ip_lock);
        /* OCFS2 *never* deletes system files. This should technically
         * never get here as system file inodes should always have a
         * positive link count. */
        if (oi->ip_flags & OCFS2_INODE_SYSTEM_FILE) {
                mlog(ML_ERROR, "Skipping delete of system file %llu\n",
                     (unsigned long long)oi->ip_blkno);
                goto bail_unlock;
        }

        ret = 1;
bail_unlock:
        spin_unlock(&oi->ip_lock);
bail:
        return ret;
}

/* Query the cluster to determine whether we should wipe an inode from
 * disk or not.
 *
 * Requires the inode to have the cluster lock. */
static int ocfs2_query_inode_wipe(struct inode *inode,
                                  struct buffer_head *di_bh,
                                  int *wipe)
{
        int status = 0, reason = 0;
        struct ocfs2_inode_info *oi = OCFS2_I(inode);
        struct ocfs2_dinode *di;

        *wipe = 0;

        trace_ocfs2_query_inode_wipe_begin((unsigned long long)oi->ip_blkno,
                                           inode->i_nlink);

        /* While we were waiting for the cluster lock in
         * ocfs2_delete_inode, another node might have asked to delete
         * the inode. Recheck our flags to catch this. */
        if (!ocfs2_inode_is_valid_to_delete(inode)) {
                reason = 1;
                goto bail;
        }

        /* Now that we have an up to date inode, we can double check
         * the link count. */
        if (inode->i_nlink)
                goto bail;

        /* Do some basic inode verification... */
        di = (struct ocfs2_dinode *) di_bh->b_data;
        if (!(di->i_flags & cpu_to_le32(OCFS2_ORPHANED_FL)) &&
            !(oi->ip_flags & OCFS2_INODE_SKIP_ORPHAN_DIR)) {
                /*
                 * Inodes in the orphan dir must have ORPHANED_FL.  The only
                 * inodes that come back out of the orphan dir are reflink
                 * targets. A reflink target may be moved out of the orphan
                 * dir between the time we scan the directory and the time we
                 * process it. This would lead to HAS_REFCOUNT_FL being set but
                 * ORPHANED_FL not.
                 */
                if (di->i_dyn_features & cpu_to_le16(OCFS2_HAS_REFCOUNT_FL)) {
                        reason = 2;
                        goto bail;
                }

                /* for lack of a better error? */
                status = -EEXIST;
                mlog(ML_ERROR,
                     "Inode %llu (on-disk %llu) not orphaned! "
                     "Disk flags  0x%x, inode flags 0x%x\n",
                     (unsigned long long)oi->ip_blkno,
                     (unsigned long long)le64_to_cpu(di->i_blkno),
                     le32_to_cpu(di->i_flags), oi->ip_flags);
                goto bail;
        }

        /* has someone already deleted us?! baaad... */
        if (di->i_dtime) {
                status = -EEXIST;
                mlog_errno(status);
                goto bail;
        }

        /*
         * This is how ocfs2 determines whether an inode is still live
         * within the cluster. Every node takes a shared read lock on
         * the inode open lock in ocfs2_read_locked_inode(). When we
         * get to ->delete_inode(), each node tries to convert it's
         * lock to an exclusive. Trylocks are serialized by the inode
         * meta data lock. If the upconvert succeeds, we know the inode
         * is no longer live and can be deleted.
         *
         * Though we call this with the meta data lock held, the
         * trylock keeps us from ABBA deadlock.
         */
        status = ocfs2_try_open_lock(inode, 1);
        if (status == -EAGAIN) {
                status = 0;
                reason = 3;
                goto bail;
        }
        if (status < 0) {
                mlog_errno(status);
                goto bail;
        }

        *wipe = 1;
        trace_ocfs2_query_inode_wipe_succ(le16_to_cpu(di->i_orphaned_slot));

bail:
        trace_ocfs2_query_inode_wipe_end(status, reason);
        return status;
}

/* Support function for ocfs2_delete_inode. Will help us keep the
 * inode data in a consistent state for clear_inode. Always truncates
 * pages, optionally sync's them first. */
static void ocfs2_cleanup_delete_inode(struct inode *inode,
                                       int sync_data)
{
        trace_ocfs2_cleanup_delete_inode(
                (unsigned long long)OCFS2_I(inode)->ip_blkno, sync_data);
        if (sync_data)
                filemap_write_and_wait(inode->i_mapping);
        truncate_inode_pages_final(&inode->i_data);
}

static void ocfs2_delete_inode(struct inode *inode)
{
        int wipe, status;
        sigset_t oldset;
        struct buffer_head *di_bh = NULL;
        struct ocfs2_dinode *di = NULL;

        trace_ocfs2_delete_inode(inode->i_ino,
                                 (unsigned long long)OCFS2_I(inode)->ip_blkno,
                                 is_bad_inode(inode));

        /* When we fail in read_inode() we mark inode as bad. The second test
         * catches the case when inode allocation fails before allocating
         * a block for inode. */
        if (is_bad_inode(inode) || !OCFS2_I(inode)->ip_blkno)
                goto bail;

        if (!ocfs2_inode_is_valid_to_delete(inode)) {
                /* It's probably not necessary to truncate_inode_pages
                 * here but we do it for safety anyway (it will most
                 * likely be a no-op anyway) */
                ocfs2_cleanup_delete_inode(inode, 0);
                goto bail;
        }

        dquot_initialize(inode);

        /* We want to block signals in delete_inode as the lock and
         * messaging paths may return us -ERESTARTSYS. Which would
         * cause us to exit early, resulting in inodes being orphaned
         * forever. */
        ocfs2_block_signals(&oldset);

        /*
         * Synchronize us against ocfs2_get_dentry. We take this in
         * shared mode so that all nodes can still concurrently
         * process deletes.
         */
        status = ocfs2_nfs_sync_lock(OCFS2_SB(inode->i_sb), 0);
        if (status < 0) {
                mlog(ML_ERROR, "getting nfs sync lock(PR) failed %d\n", status);
                ocfs2_cleanup_delete_inode(inode, 0);
                goto bail_unblock;
        }
        /* Lock down the inode. This gives us an up to date view of
         * it's metadata (for verification), and allows us to
         * serialize delete_inode on multiple nodes.
         *
         * Even though we might be doing a truncate, we don't take the
         * allocation lock here as it won't be needed - nobody will
         * have the file open.
         */
        status = ocfs2_inode_lock(inode, &di_bh, 1);
        if (status < 0) {
                if (status != -ENOENT)
                        mlog_errno(status);
                ocfs2_cleanup_delete_inode(inode, 0);
                goto bail_unlock_nfs_sync;
        }

        di = (struct ocfs2_dinode *)di_bh->b_data;
        /* Skip inode deletion and wait for dio orphan entry recovered
         * first */
        if (unlikely(di->i_flags & cpu_to_le32(OCFS2_DIO_ORPHANED_FL))) {
                ocfs2_cleanup_delete_inode(inode, 0);
                goto bail_unlock_inode;
        }

        /* Query the cluster. This will be the final decision made
         * before we go ahead and wipe the inode. */
        status = ocfs2_query_inode_wipe(inode, di_bh, &wipe);
        if (!wipe || status < 0) {
                /* Error and remote inode busy both mean we won't be
                 * removing the inode, so they take almost the same
                 * path. */
                if (status < 0)
                        mlog_errno(status);

                /* Someone in the cluster has disallowed a wipe of
                 * this inode, or it was never completely
                 * orphaned. Write out the pages and exit now. */
                ocfs2_cleanup_delete_inode(inode, 1);
                goto bail_unlock_inode;
        }

        ocfs2_cleanup_delete_inode(inode, 0);

        status = ocfs2_wipe_inode(inode, di_bh);
        if (status < 0) {
                if (status != -EDEADLK)
                        mlog_errno(status);
                goto bail_unlock_inode;
        }

        /*
         * Mark the inode as successfully deleted.
         *
         * This is important for ocfs2_clear_inode() as it will check
         * this flag and skip any checkpointing work
         *
         * ocfs2_stuff_meta_lvb() also uses this flag to invalidate
         * the LVB for other nodes.
         */
        OCFS2_I(inode)->ip_flags |= OCFS2_INODE_DELETED;

bail_unlock_inode:
        ocfs2_inode_unlock(inode, 1);
        brelse(di_bh);

bail_unlock_nfs_sync:
        ocfs2_nfs_sync_unlock(OCFS2_SB(inode->i_sb), 0);

bail_unblock:
        ocfs2_unblock_signals(&oldset);
bail:
        return;
}

static void ocfs2_clear_inode(struct inode *inode)
{
        int status;
        struct ocfs2_inode_info *oi = OCFS2_I(inode);
        struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);

        clear_inode(inode);
        trace_ocfs2_clear_inode((unsigned long long)oi->ip_blkno,
                                inode->i_nlink);

        mlog_bug_on_msg(OCFS2_SB(inode->i_sb) == NULL,
                        "Inode=%lu\n", inode->i_ino);

        dquot_drop(inode);

        /* To preven remote deletes we hold open lock before, now it
         * is time to unlock PR and EX open locks. */
        ocfs2_open_unlock(inode);

        /* Do these before all the other work so that we don't bounce
         * the downconvert thread while waiting to destroy the locks. */
        ocfs2_mark_lockres_freeing(osb, &oi->ip_rw_lockres);
        ocfs2_mark_lockres_freeing(osb, &oi->ip_inode_lockres);
        ocfs2_mark_lockres_freeing(osb, &oi->ip_open_lockres);

        ocfs2_resv_discard(&OCFS2_SB(inode->i_sb)->osb_la_resmap,
                           &oi->ip_la_data_resv);
        ocfs2_resv_init_once(&oi->ip_la_data_resv);

        /* We very well may get a clear_inode before all an inodes
         * metadata has hit disk. Of course, we can't drop any cluster
         * locks until the journal has finished with it. The only
         * exception here are successfully wiped inodes - their
         * metadata can now be considered to be part of the system
         * inodes from which it came. */
        if (!(OCFS2_I(inode)->ip_flags & OCFS2_INODE_DELETED))
                ocfs2_checkpoint_inode(inode);

        mlog_bug_on_msg(!list_empty(&oi->ip_io_markers),
                        "Clear inode of %llu, inode has io markers\n",
                        (unsigned long long)oi->ip_blkno);
        mlog_bug_on_msg(!list_empty(&oi->ip_unwritten_list),
                        "Clear inode of %llu, inode has unwritten extents\n",
                        (unsigned long long)oi->ip_blkno);

        ocfs2_extent_map_trunc(inode, 0);

        status = ocfs2_drop_inode_locks(inode);
        if (status < 0)
                mlog_errno(status);

        ocfs2_lock_res_free(&oi->ip_rw_lockres);
        ocfs2_lock_res_free(&oi->ip_inode_lockres);
        ocfs2_lock_res_free(&oi->ip_open_lockres);

        ocfs2_metadata_cache_exit(INODE_CACHE(inode));

        mlog_bug_on_msg(INODE_CACHE(inode)->ci_num_cached,
                        "Clear inode of %llu, inode has %u cache items\n",
                        (unsigned long long)oi->ip_blkno,
                        INODE_CACHE(inode)->ci_num_cached);

        mlog_bug_on_msg(!(INODE_CACHE(inode)->ci_flags & OCFS2_CACHE_FL_INLINE),
                        "Clear inode of %llu, inode has a bad flag\n",
                        (unsigned long long)oi->ip_blkno);

        mlog_bug_on_msg(spin_is_locked(&oi->ip_lock),
                        "Clear inode of %llu, inode is locked\n",
                        (unsigned long long)oi->ip_blkno);

        mlog_bug_on_msg(!mutex_trylock(&oi->ip_io_mutex),
                        "Clear inode of %llu, io_mutex is locked\n",
                        (unsigned long long)oi->ip_blkno);
        mutex_unlock(&oi->ip_io_mutex);

        /*
         * down_trylock() returns 0, down_write_trylock() returns 1
         * kernel 1, world 0
         */
        mlog_bug_on_msg(!down_write_trylock(&oi->ip_alloc_sem),
                        "Clear inode of %llu, alloc_sem is locked\n",
                        (unsigned long long)oi->ip_blkno);
        up_write(&oi->ip_alloc_sem);

        mlog_bug_on_msg(oi->ip_open_count,
                        "Clear inode of %llu has open count %d\n",
                        (unsigned long long)oi->ip_blkno, oi->ip_open_count);

        /* Clear all other flags. */
        oi->ip_flags = 0;
        oi->ip_dir_start_lookup = 0;
        oi->ip_blkno = 0ULL;

        /*
         * ip_jinode is used to track txns against this inode. We ensure that
         * the journal is flushed before journal shutdown. Thus it is safe to
         * have inodes get cleaned up after journal shutdown.
         */
        jbd2_journal_release_jbd_inode(OCFS2_SB(inode->i_sb)->journal->j_journal,
                                       &oi->ip_jinode);
}

void ocfs2_evict_inode(struct inode *inode)
{
        if (!inode->i_nlink ||
            (OCFS2_I(inode)->ip_flags & OCFS2_INODE_MAYBE_ORPHANED)) {
                ocfs2_delete_inode(inode);
        } else {
                truncate_inode_pages_final(&inode->i_data);
        }
        ocfs2_clear_inode(inode);
}

/* Called under inode_lock, with no more references on the
 * struct inode, so it's safe here to check the flags field
 * and to manipulate i_nlink without any other locks. */
int ocfs2_drop_inode(struct inode *inode)
{
        struct ocfs2_inode_info *oi = OCFS2_I(inode);

        trace_ocfs2_drop_inode((unsigned long long)oi->ip_blkno,
                                inode->i_nlink, oi->ip_flags);

        assert_spin_locked(&inode->i_lock);
        inode->i_state |= I_WILL_FREE;
        spin_unlock(&inode->i_lock);
        write_inode_now(inode, 1);
        spin_lock(&inode->i_lock);
        WARN_ON(inode->i_state & I_NEW);
        inode->i_state &= ~I_WILL_FREE;

        return 1;
}

/*
 * This is called from our getattr.
 */
int ocfs2_inode_revalidate(struct dentry *dentry)
{
        struct inode *inode = d_inode(dentry);
        int status = 0;

        trace_ocfs2_inode_revalidate(inode,
                inode ? (unsigned long long)OCFS2_I(inode)->ip_blkno : 0ULL,
                inode ? (unsigned long long)OCFS2_I(inode)->ip_flags : 0);

        if (!inode) {
                status = -ENOENT;
                goto bail;
        }

        spin_lock(&OCFS2_I(inode)->ip_lock);
        if (OCFS2_I(inode)->ip_flags & OCFS2_INODE_DELETED) {
                spin_unlock(&OCFS2_I(inode)->ip_lock);
                status = -ENOENT;
                goto bail;
        }
        spin_unlock(&OCFS2_I(inode)->ip_lock);

        /* Let ocfs2_inode_lock do the work of updating our struct
         * inode for us. */
        status = ocfs2_inode_lock(inode, NULL, 0);
        if (status < 0) {
                if (status != -ENOENT)
                        mlog_errno(status);
                goto bail;
        }
        ocfs2_inode_unlock(inode, 0);
bail:
        return status;
}

/*
 * Updates a disk inode from a
 * struct inode.
 * Only takes ip_lock.
 */
int ocfs2_mark_inode_dirty(handle_t *handle,
                           struct inode *inode,
                           struct buffer_head *bh)
{
        int status;
        struct ocfs2_dinode *fe = (struct ocfs2_dinode *) bh->b_data;

        trace_ocfs2_mark_inode_dirty((unsigned long long)OCFS2_I(inode)->ip_blkno);

        status = ocfs2_journal_access_di(handle, INODE_CACHE(inode), bh,
                                         OCFS2_JOURNAL_ACCESS_WRITE);
        if (status < 0) {
                mlog_errno(status);
                goto leave;
        }

        spin_lock(&OCFS2_I(inode)->ip_lock);
        fe->i_clusters = cpu_to_le32(OCFS2_I(inode)->ip_clusters);
        ocfs2_get_inode_flags(OCFS2_I(inode));
        fe->i_attr = cpu_to_le32(OCFS2_I(inode)->ip_attr);
        fe->i_dyn_features = cpu_to_le16(OCFS2_I(inode)->ip_dyn_features);
        spin_unlock(&OCFS2_I(inode)->ip_lock);

        fe->i_size = cpu_to_le64(i_size_read(inode));
        ocfs2_set_links_count(fe, inode->i_nlink);
        fe->i_uid = cpu_to_le32(i_uid_read(inode));
        fe->i_gid = cpu_to_le32(i_gid_read(inode));
        fe->i_mode = cpu_to_le16(inode->i_mode);
        fe->i_atime = cpu_to_le64(inode->i_atime.tv_sec);
        fe->i_atime_nsec = cpu_to_le32(inode->i_atime.tv_nsec);
        fe->i_ctime = cpu_to_le64(inode->i_ctime.tv_sec);
        fe->i_ctime_nsec = cpu_to_le32(inode->i_ctime.tv_nsec);
        fe->i_mtime = cpu_to_le64(inode->i_mtime.tv_sec);
        fe->i_mtime_nsec = cpu_to_le32(inode->i_mtime.tv_nsec);

        ocfs2_journal_dirty(handle, bh);
        ocfs2_update_inode_fsync_trans(handle, inode, 1);
leave:
        return status;
}

/*
 *
 * Updates a struct inode from a disk inode.
 * does no i/o, only takes ip_lock.
 */
void ocfs2_refresh_inode(struct inode *inode,
                         struct ocfs2_dinode *fe)
{
        spin_lock(&OCFS2_I(inode)->ip_lock);

        OCFS2_I(inode)->ip_clusters = le32_to_cpu(fe->i_clusters);
        OCFS2_I(inode)->ip_attr = le32_to_cpu(fe->i_attr);
        OCFS2_I(inode)->ip_dyn_features = le16_to_cpu(fe->i_dyn_features);
        ocfs2_set_inode_flags(inode);
        i_size_write(inode, le64_to_cpu(fe->i_size));
        set_nlink(inode, ocfs2_read_links_count(fe));
        i_uid_write(inode, le32_to_cpu(fe->i_uid));
        i_gid_write(inode, le32_to_cpu(fe->i_gid));
        inode->i_mode = le16_to_cpu(fe->i_mode);
        if (S_ISLNK(inode->i_mode) && le32_to_cpu(fe->i_clusters) == 0)
                inode->i_blocks = 0;
        else
                inode->i_blocks = ocfs2_inode_sector_count(inode);
        inode->i_atime.tv_sec = le64_to_cpu(fe->i_atime);
        inode->i_atime.tv_nsec = le32_to_cpu(fe->i_atime_nsec);
        inode->i_mtime.tv_sec = le64_to_cpu(fe->i_mtime);
        inode->i_mtime.tv_nsec = le32_to_cpu(fe->i_mtime_nsec);
        inode->i_ctime.tv_sec = le64_to_cpu(fe->i_ctime);
        inode->i_ctime.tv_nsec = le32_to_cpu(fe->i_ctime_nsec);

        spin_unlock(&OCFS2_I(inode)->ip_lock);
}

int ocfs2_validate_inode_block(struct super_block *sb,
                               struct buffer_head *bh)
{
        int rc;
        struct ocfs2_dinode *di = (struct ocfs2_dinode *)bh->b_data;

        trace_ocfs2_validate_inode_block((unsigned long long)bh->b_blocknr);

        BUG_ON(!buffer_uptodate(bh));

        /*
         * If the ecc fails, we return the error but otherwise
         * leave the filesystem running.  We know any error is
         * local to this block.
         */
        rc = ocfs2_validate_meta_ecc(sb, bh->b_data, &di->i_check);
        if (rc) {
                mlog(ML_ERROR, "Checksum failed for dinode %llu\n",
                     (unsigned long long)bh->b_blocknr);
                goto bail;
        }

        /*
         * Errors after here are fatal.
         */

        rc = -EINVAL;

        if (!OCFS2_IS_VALID_DINODE(di)) {
                rc = ocfs2_error(sb, "Invalid dinode #%llu: signature = %.*s\n",
                                 (unsigned long long)bh->b_blocknr, 7,
                                 di->i_signature);
                goto bail;
        }

        if (le64_to_cpu(di->i_blkno) != bh->b_blocknr) {
                rc = ocfs2_error(sb, "Invalid dinode #%llu: i_blkno is %llu\n",
                                 (unsigned long long)bh->b_blocknr,
                                 (unsigned long long)le64_to_cpu(di->i_blkno));
                goto bail;
        }

        if (!(di->i_flags & cpu_to_le32(OCFS2_VALID_FL))) {
                rc = ocfs2_error(sb,
                                 "Invalid dinode #%llu: OCFS2_VALID_FL not set\n",
                                 (unsigned long long)bh->b_blocknr);
                goto bail;
        }

        if (le32_to_cpu(di->i_fs_generation) !=
            OCFS2_SB(sb)->fs_generation) {
                rc = ocfs2_error(sb,
                                 "Invalid dinode #%llu: fs_generation is %u\n",
                                 (unsigned long long)bh->b_blocknr,
                                 le32_to_cpu(di->i_fs_generation));
                goto bail;
        }

        rc = 0;

bail:
        return rc;
}

static int ocfs2_filecheck_validate_inode_block(struct super_block *sb,
                                                struct buffer_head *bh)
{
        int rc = 0;
        struct ocfs2_dinode *di = (struct ocfs2_dinode *)bh->b_data;

        trace_ocfs2_filecheck_validate_inode_block(
                (unsigned long long)bh->b_blocknr);

        BUG_ON(!buffer_uptodate(bh));

        /*
         * Call ocfs2_validate_meta_ecc() first since it has ecc repair
         * function, but we should not return error immediately when ecc
         * validation fails, because the reason is quite likely the invalid
         * inode number inputed.
         */
        rc = ocfs2_validate_meta_ecc(sb, bh->b_data, &di->i_check);
        if (rc) {
                mlog(ML_ERROR,
                     "Filecheck: checksum failed for dinode %llu\n",
                     (unsigned long long)bh->b_blocknr);
                rc = -OCFS2_FILECHECK_ERR_BLOCKECC;
        }

        if (!OCFS2_IS_VALID_DINODE(di)) {
                mlog(ML_ERROR,
                     "Filecheck: invalid dinode #%llu: signature = %.*s\n",
                     (unsigned long long)bh->b_blocknr, 7, di->i_signature);
                rc = -OCFS2_FILECHECK_ERR_INVALIDINO;
                goto bail;
        } else if (rc)
                goto bail;

        if (le64_to_cpu(di->i_blkno) != bh->b_blocknr) {
                mlog(ML_ERROR,
                     "Filecheck: invalid dinode #%llu: i_blkno is %llu\n",
                     (unsigned long long)bh->b_blocknr,
                     (unsigned long long)le64_to_cpu(di->i_blkno));
                rc = -OCFS2_FILECHECK_ERR_BLOCKNO;
                goto bail;
        }

        if (!(di->i_flags & cpu_to_le32(OCFS2_VALID_FL))) {
                mlog(ML_ERROR,
                     "Filecheck: invalid dinode #%llu: OCFS2_VALID_FL "
                     "not set\n",
                     (unsigned long long)bh->b_blocknr);
                rc = -OCFS2_FILECHECK_ERR_VALIDFLAG;
                goto bail;
        }

        if (le32_to_cpu(di->i_fs_generation) !=
            OCFS2_SB(sb)->fs_generation) {
                mlog(ML_ERROR,
                     "Filecheck: invalid dinode #%llu: fs_generation is %u\n",
                     (unsigned long long)bh->b_blocknr,
                     le32_to_cpu(di->i_fs_generation));
                rc = -OCFS2_FILECHECK_ERR_GENERATION;
                goto bail;
        }

bail:
        return rc;
}

static int ocfs2_filecheck_repair_inode_block(struct super_block *sb,
                                              struct buffer_head *bh)
{
        int changed = 0;
        struct ocfs2_dinode *di = (struct ocfs2_dinode *)bh->b_data;

        if (!ocfs2_filecheck_validate_inode_block(sb, bh))
                return 0;

        trace_ocfs2_filecheck_repair_inode_block(
                (unsigned long long)bh->b_blocknr);

        if (ocfs2_is_hard_readonly(OCFS2_SB(sb)) ||
            ocfs2_is_soft_readonly(OCFS2_SB(sb))) {
                mlog(ML_ERROR,
                     "Filecheck: cannot repair dinode #%llu "
                     "on readonly filesystem\n",
                     (unsigned long long)bh->b_blocknr);
                return -OCFS2_FILECHECK_ERR_READONLY;
        }

        if (buffer_jbd(bh)) {
                mlog(ML_ERROR,
                     "Filecheck: cannot repair dinode #%llu, "
                     "its buffer is in jbd\n",
                     (unsigned long long)bh->b_blocknr);
                return -OCFS2_FILECHECK_ERR_INJBD;
        }

        if (!OCFS2_IS_VALID_DINODE(di)) {
                /* Cannot fix invalid inode block */
                return -OCFS2_FILECHECK_ERR_INVALIDINO;
        }

        if (!(di->i_flags & cpu_to_le32(OCFS2_VALID_FL))) {
                /* Cannot just add VALID_FL flag back as a fix,
                 * need more things to check here.
                 */
                return -OCFS2_FILECHECK_ERR_VALIDFLAG;
        }

        if (le64_to_cpu(di->i_blkno) != bh->b_blocknr) {
                di->i_blkno = cpu_to_le64(bh->b_blocknr);
                changed = 1;
                mlog(ML_ERROR,
                     "Filecheck: reset dinode #%llu: i_blkno to %llu\n",
                     (unsigned long long)bh->b_blocknr,
                     (unsigned long long)le64_to_cpu(di->i_blkno));
        }

        if (le32_to_cpu(di->i_fs_generation) !=
            OCFS2_SB(sb)->fs_generation) {
                di->i_fs_generation = cpu_to_le32(OCFS2_SB(sb)->fs_generation);
                changed = 1;
                mlog(ML_ERROR,
                     "Filecheck: reset dinode #%llu: fs_generation to %u\n",
                     (unsigned long long)bh->b_blocknr,
                     le32_to_cpu(di->i_fs_generation));
        }

        if (changed || ocfs2_validate_meta_ecc(sb, bh->b_data, &di->i_check)) {
                ocfs2_compute_meta_ecc(sb, bh->b_data, &di->i_check);
                mark_buffer_dirty(bh);
                mlog(ML_ERROR,
                     "Filecheck: reset dinode #%llu: compute meta ecc\n",
                     (unsigned long long)bh->b_blocknr);
        }

        return 0;
}

static int
ocfs2_filecheck_read_inode_block_full(struct inode *inode,
                                      struct buffer_head **bh,
                                      int flags, int type)
{
        int rc;
        struct buffer_head *tmp = *bh;

        if (!type) /* Check inode block */
                rc = ocfs2_read_blocks(INODE_CACHE(inode),
                                OCFS2_I(inode)->ip_blkno,
                                1, &tmp, flags,
                                ocfs2_filecheck_validate_inode_block);
        else /* Repair inode block */
                rc = ocfs2_read_blocks(INODE_CACHE(inode),
                                OCFS2_I(inode)->ip_blkno,
                                1, &tmp, flags,
                                ocfs2_filecheck_repair_inode_block);

        /* If ocfs2_read_blocks() got us a new bh, pass it up. */
        if (!rc && !*bh)
                *bh = tmp;

        return rc;
}

int ocfs2_read_inode_block_full(struct inode *inode, struct buffer_head **bh,
                                int flags)
{
        int rc;
        struct buffer_head *tmp = *bh;

        rc = ocfs2_read_blocks(INODE_CACHE(inode), OCFS2_I(inode)->ip_blkno,
                               1, &tmp, flags, ocfs2_validate_inode_block);

        /* If ocfs2_read_blocks() got us a new bh, pass it up. */
        if (!rc && !*bh)
                *bh = tmp;

        return rc;
}

int ocfs2_read_inode_block(struct inode *inode, struct buffer_head **bh)
{
        return ocfs2_read_inode_block_full(inode, bh, 0);
}


static u64 ocfs2_inode_cache_owner(struct ocfs2_caching_info *ci)
{
        struct ocfs2_inode_info *oi = cache_info_to_inode(ci);

        return oi->ip_blkno;
}

static struct super_block *ocfs2_inode_cache_get_super(struct ocfs2_caching_info *ci)
{
        struct ocfs2_inode_info *oi = cache_info_to_inode(ci);

        return oi->vfs_inode.i_sb;
}

static void ocfs2_inode_cache_lock(struct ocfs2_caching_info *ci)
{
        struct ocfs2_inode_info *oi = cache_info_to_inode(ci);

        spin_lock(&oi->ip_lock);
}

static void ocfs2_inode_cache_unlock(struct ocfs2_caching_info *ci)
{
        struct ocfs2_inode_info *oi = cache_info_to_inode(ci);

        spin_unlock(&oi->ip_lock);
}

static void ocfs2_inode_cache_io_lock(struct ocfs2_caching_info *ci)
{
        struct ocfs2_inode_info *oi = cache_info_to_inode(ci);

        mutex_lock(&oi->ip_io_mutex);
}

static void ocfs2_inode_cache_io_unlock(struct ocfs2_caching_info *ci)
{
        struct ocfs2_inode_info *oi = cache_info_to_inode(ci);

        mutex_unlock(&oi->ip_io_mutex);
}

const struct ocfs2_caching_operations ocfs2_inode_caching_ops = {
        .co_owner               = ocfs2_inode_cache_owner,
        .co_get_super           = ocfs2_inode_cache_get_super,
        .co_cache_lock          = ocfs2_inode_cache_lock,
        .co_cache_unlock        = ocfs2_inode_cache_unlock,
        .co_io_lock             = ocfs2_inode_cache_io_lock,
        .co_io_unlock           = ocfs2_inode_cache_io_unlock,
};