ocfs2: Read from an unwritten extent returns zeros

[safe/jmp/linux-2.6] / 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/slab.h>
#include <linux/highmem.h>
#include <linux/pagemap.h>
#include <linux/smp_lock.h>

#include <asm/byteorder.h>

#define MLOG_MASK_PREFIX ML_INODE
#include <cluster/masklog.h>

#include "ocfs2.h"

#include "alloc.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 "vote.h"

#include "buffer_head_io.h"

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

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);

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;
}

struct inode *ocfs2_iget(struct ocfs2_super *osb, u64 blkno, int flags)
{
        struct inode *inode = NULL;
        struct super_block *sb = osb->sb;
        struct ocfs2_find_inode_args args;

        mlog_entry("(blkno = %llu)\n", (unsigned long long)blkno);

        /* 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);

        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 && inode->i_state & I_NEW) {
                mlog(0, "Inode was not in inode cache, reading it.\n");
                ocfs2_read_locked_inode(inode, &args);
                unlock_new_inode(inode);
        }
        if (inode == NULL) {
                inode = ERR_PTR(-ENOMEM);
                mlog_errno(PTR_ERR(inode));
                goto bail;
        }
        if (is_bad_inode(inode)) {
                iput(inode);
                inode = ERR_PTR(-ESTALE);
                goto bail;
        }

bail:
        if (!IS_ERR(inode)) {
                mlog(0, "returning inode with number %llu\n",
                     (unsigned long long)OCFS2_I(inode)->ip_blkno);
                mlog_exit_ptr(inode);
        }

        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;

        mlog_entry("(0x%p, %lu, 0x%p)\n", inode, inode->i_ino, opaque);

        args = opaque;

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

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

        ret = 1;
bail:
        mlog_exit(ret);
        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;

        mlog_entry("inode = %p, opaque = %p\n", inode, opaque);

        inode->i_ino = args->fi_ino;
        OCFS2_I(inode)->ip_blkno = args->fi_blkno;

        mlog_exit(0);
        return 0;
}

int ocfs2_populate_inode(struct inode *inode, struct ocfs2_dinode *fe,
                         int create_ino)
{
        struct super_block *sb;
        struct ocfs2_super *osb;
        int status = -EINVAL;

        mlog_entry("(0x%p, size:%llu)\n", inode,
                   (unsigned long long)fe->i_size);

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

        /* this means that read_inode cannot create a superblock inode
         * today.  change if needed. */
        if (!OCFS2_IS_VALID_DINODE(fe) ||
            !(fe->i_flags & cpu_to_le32(OCFS2_VALID_FL))) {
                mlog(0, "Invalid dinode: i_ino=%lu, i_blkno=%llu, "
                     "signature = %.*s, flags = 0x%x\n",
                     inode->i_ino,
                     (unsigned long long)le64_to_cpu(fe->i_blkno), 7,
                     fe->i_signature, le32_to_cpu(fe->i_flags));
                goto bail;
        }

        if (le32_to_cpu(fe->i_fs_generation) != osb->fs_generation) {
                mlog(ML_ERROR, "file entry generation does not match "
                     "superblock! osb->fs_generation=%x, "
                     "fe->i_fs_generation=%x\n",
                     osb->fs_generation, le32_to_cpu(fe->i_fs_generation));
                goto bail;
        }

        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);
        inode->i_uid = le32_to_cpu(fe->i_uid);
        inode->i_gid = 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;
        else
                inode->i_blocks =
                        ocfs2_align_bytes_to_sectors(le64_to_cpu(fe->i_size));
        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)fe->i_blkno);

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

        inode->i_nlink = le16_to_cpu(fe->i_links_count);

        if (fe->i_flags & cpu_to_le32(OCFS2_SYSTEM_FL))
                OCFS2_I(inode)->ip_flags |= OCFS2_INODE_SYSTEM_FILE;

        if (fe->i_flags & cpu_to_le32(OCFS2_LOCAL_ALLOC_FL)) {
                OCFS2_I(inode)->ip_flags |= OCFS2_INODE_BITMAP;
                mlog(0, "local alloc inode: i_ino=%lu\n", inode->i_ino);
        } 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_SUPER_BLOCK_FL)) {
                mlog(0, "superblock inode: i_ino=%lu\n", inode->i_ino);
                /* we can't actually hit this as read_inode can't
                 * handle superblocks today ;-) */
                BUG();
        }

        switch (inode->i_mode & S_IFMT) {
            case S_IFREG:
                    inode->i_fop = &ocfs2_fops;
                    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;
                    inode->i_fop = &ocfs2_dops;
                    i_size_write(inode, le64_to_cpu(fe->i_size));
                    break;
            case S_IFLNK:
                    if (ocfs2_inode_is_fast_symlink(inode))
                        inode->i_op = &ocfs2_fast_symlink_inode_operations;
                    else
                        inode->i_op = &ocfs2_symlink_inode_operations;
                    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(fe->i_flags & cpu_to_le32(OCFS2_SYSTEM_FL));

                ocfs2_inode_lock_res_init(&OCFS2_I(inode)->ip_meta_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_inode_lock_res_init(&OCFS2_I(inode)->ip_data_lockres,
                                  OCFS2_LOCK_TYPE_DATA, inode->i_generation,
                                  inode);

        ocfs2_set_inode_flags(inode);

        status = 0;
bail:
        mlog_exit(status);
        return status;
}

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;
        u32 generation = 0;

        mlog_entry("(0x%p, 0x%p)\n", inode, args);

        status = -EINVAL;
        if (inode == NULL || inode->i_sb == NULL) {
                mlog(ML_ERROR, "bad inode\n");
                return status;
        }
        sb = inode->i_sb;
        osb = OCFS2_SB(sb);

        if (!args) {
                mlog(ML_ERROR, "bad inode args\n");
                make_bad_inode(inode);
                return status;
        }

        /*
         * 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-accesible 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);

        /*
         * 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_meta_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_meta_lock(inode, NULL, 0);
                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;
                }
        }

        status = ocfs2_read_block(osb, args->fi_blkno, &bh, 0,
                                  can_lock ? inode : NULL);
        if (status < 0) {
                mlog_errno(status);
                goto bail;
        }

        status = -EINVAL;
        fe = (struct ocfs2_dinode *) bh->b_data;
        if (!OCFS2_IS_VALID_DINODE(fe)) {
                mlog(ML_ERROR, "Invalid dinode #%llu: signature = %.*s\n",
                     (unsigned long long)fe->i_blkno, 7, fe->i_signature);
                goto bail;
        }

        /*
         * 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));

        if (ocfs2_populate_inode(inode, fe, 0) < 0)
                goto bail;

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

        status = 0;

bail:
        if (can_lock)
                ocfs2_meta_unlock(inode, 0);

        if (status < 0)
                make_bad_inode(inode);

        if (args && bh)
                brelse(bh);

        mlog_exit(status);
        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_truncate_context *tc = NULL;
        struct ocfs2_dinode *fe;
        handle_t *handle = NULL;

        mlog_entry_void();

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

        if (fe->i_clusters) {
                handle = ocfs2_start_trans(osb, OCFS2_INODE_UPDATE_CREDITS);
                if (IS_ERR(handle)) {
                        status = PTR_ERR(handle);
                        mlog_errno(status);
                        goto out;
                }

                status = ocfs2_journal_access(handle, 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_prepare_truncate(osb, inode, fe_bh, &tc);
                if (status < 0) {
                        mlog_errno(status);
                        goto out;
                }

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

out:
        if (handle)
                ocfs2_commit_trans(osb, handle);
        mlog_exit(status);
        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 = -EEXIST;
                mlog_errno(status);
                goto bail;
        }

        mutex_lock(&inode_alloc_inode->i_mutex);
        status = ocfs2_meta_lock(inode_alloc_inode, &inode_alloc_bh, 1);
        if (status < 0) {
                mutex_unlock(&inode_alloc_inode->i_mutex);

                mlog_errno(status);
                goto bail;
        }

        handle = ocfs2_start_trans(osb, OCFS2_DELETE_INODE_CREDITS);
        if (IS_ERR(handle)) {
                status = PTR_ERR(handle);
                mlog_errno(status);
                goto bail_unlock;
        }

        status = ocfs2_orphan_del(osb, handle, orphan_dir_inode, inode,
                                  orphan_dir_bh);
        if (status < 0) {
                mlog_errno(status);
                goto bail_commit;
        }

        /* set the inodes dtime */
        status = ocfs2_journal_access(handle, inode, di_bh,
                                      OCFS2_JOURNAL_ACCESS_WRITE);
        if (status < 0) {
                mlog_errno(status);
                goto bail_commit;
        }

        di->i_dtime = cpu_to_le64(CURRENT_TIME.tv_sec);
        le32_and_cpu(&di->i_flags, ~(OCFS2_VALID_FL | OCFS2_ORPHANED_FL));

        status = ocfs2_journal_dirty(handle, di_bh);
        if (status < 0) {
                mlog_errno(status);
                goto bail_commit;
        }

        ocfs2_remove_from_cache(inode, di_bh);

        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_meta_unlock(inode_alloc_inode, 1);
        mutex_unlock(&inode_alloc_inode->i_mutex);
        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)) {
                mlog(0, "Recovery is happening on orphan dir %d, will skip "
                     "this inode\n", 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);
        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;
        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;

        di = (struct ocfs2_dinode *) di_bh->b_data;
        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 = -EEXIST;
                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. */
        mutex_lock(&orphan_dir_inode->i_mutex);
        status = ocfs2_meta_lock(orphan_dir_inode, &orphan_dir_bh, 1);
        if (status < 0) {
                mutex_unlock(&orphan_dir_inode->i_mutex);

                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 vote for
         * an inode delete on 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;
        }

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

bail_unlock_dir:
        ocfs2_meta_unlock(orphan_dir_inode, 1);
        mutex_unlock(&orphan_dir_inode->i_mutex);
        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
 * vote 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);

        /* 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 process_vote we can't go into our own
         * voting [hello, deadlock city!], so unforuntately we just
         * have to skip deleting this guy. That's OK though because
         * the node who's doing the actual deleting should handle it
         * anyway. */
        if (current == osb->vote_task) {
                mlog(0, "Skipping delete of %lu because we're currently "
                     "in process_vote\n", inode->i_ino);
                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;
        }

        /* If we have voted "yes" on the wipe of this inode for
         * another node, it will be marked here so we can safely skip
         * it. Recovery will cleanup any inodes we might inadvertantly
         * skip here. */
        if (oi->ip_flags & OCFS2_INODE_SKIP_DELETE) {
                mlog(0, "Skipping delete of %lu because another node "
                     "has done this for us.\n", inode->i_ino);
                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;
        struct ocfs2_inode_info *oi = OCFS2_I(inode);
        struct ocfs2_dinode *di;

        *wipe = 0;

        /* 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)) {
                mlog(0, "Skipping delete of %llu because flags changed\n",
                     (unsigned long long)oi->ip_blkno);
                goto bail;
        }

        /* Now that we have an up to date inode, we can double check
         * the link count. */
        if (inode->i_nlink) {
                mlog(0, "Skipping delete of %llu because nlink = %u\n",
                     (unsigned long long)oi->ip_blkno, 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))) {
                /* 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)di->i_blkno, 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 suceeds, 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;
                mlog(0, "Skipping delete of %llu because it is in use on"
                     "other nodes\n", (unsigned long long)oi->ip_blkno);
                goto bail;
        }
        if (status < 0) {
                mlog_errno(status);
                goto bail;
        }

        *wipe = 1;
        mlog(0, "Inode %llu is ok to wipe from orphan dir %u\n",
             (unsigned long long)oi->ip_blkno,
             le16_to_cpu(di->i_orphaned_slot));

bail:
        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)
{
        mlog(0, "Cleanup inode %llu, sync = %d\n",
             (unsigned long long)OCFS2_I(inode)->ip_blkno, sync_data);
        if (sync_data)
                write_inode_now(inode, 1);
        truncate_inode_pages(&inode->i_data, 0);
}

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

        mlog_entry("(inode->i_ino = %lu)\n", inode->i_ino);

        if (is_bad_inode(inode)) {
                mlog(0, "Skipping delete of bad inode\n");
                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;
        }

        /* 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. */
        sigfillset(&blocked);
        status = sigprocmask(SIG_BLOCK, &blocked, &oldset);
        if (status < 0) {
                mlog_errno(status);
                ocfs2_cleanup_delete_inode(inode, 1);
                goto bail;
        }

        /* 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 votes. 
         *
         * 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_meta_lock(inode, &di_bh, 1);
        if (status < 0) {
                if (status != -ENOENT)
                        mlog_errno(status);
                ocfs2_cleanup_delete_inode(inode, 0);
                goto bail_unblock;
        }

        /* 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 inode busy vote 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 voted to not wipe 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_meta_unlock(inode, 1);
        brelse(di_bh);
bail_unblock:
        status = sigprocmask(SIG_SETMASK, &oldset, NULL);
        if (status < 0)
                mlog_errno(status);
bail:
        clear_inode(inode);
        mlog_exit_void();
}

void ocfs2_clear_inode(struct inode *inode)
{
        int status;
        struct ocfs2_inode_info *oi = OCFS2_I(inode);

        mlog_entry_void();

        if (!inode)
                goto bail;

        mlog(0, "Clearing inode: %llu, nlink = %u\n",
             (unsigned long long)OCFS2_I(inode)->ip_blkno, inode->i_nlink);

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

        /* For remove delete_inode vote, 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 vote thread while waiting to destroy the locks. */
        ocfs2_mark_lockres_freeing(&oi->ip_rw_lockres);
        ocfs2_mark_lockres_freeing(&oi->ip_meta_lockres);
        ocfs2_mark_lockres_freeing(&oi->ip_data_lockres);
        ocfs2_mark_lockres_freeing(&oi->ip_open_lockres);

        /* 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);

        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_meta_lockres);
        ocfs2_lock_res_free(&oi->ip_data_lockres);
        ocfs2_lock_res_free(&oi->ip_open_lockres);

        ocfs2_metadata_cache_purge(inode);

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

        mlog_bug_on_msg(!(oi->ip_flags & OCFS2_INODE_CACHE_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 = OCFS2_INODE_CACHE_INLINE;
        oi->ip_created_trans = 0;
        oi->ip_last_trans = 0;
        oi->ip_dir_start_lookup = 0;
        oi->ip_blkno = 0ULL;

bail:
        mlog_exit_void();
}

/* 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. */
void ocfs2_drop_inode(struct inode *inode)
{
        struct ocfs2_inode_info *oi = OCFS2_I(inode);

        mlog_entry_void();

        mlog(0, "Drop inode %llu, nlink = %u, ip_flags = 0x%x\n",
             (unsigned long long)oi->ip_blkno, inode->i_nlink, oi->ip_flags);

        if (oi->ip_flags & OCFS2_INODE_MAYBE_ORPHANED)
                generic_delete_inode(inode);
        else
                generic_drop_inode(inode);

        mlog_exit_void();
}

/*
 * TODO: this should probably be merged into ocfs2_get_block
 *
 * However, you now need to pay attention to the cont_prepare_write()
 * stuff in ocfs2_get_block (that is, ocfs2_get_block pretty much
 * expects never to extend).
 */
struct buffer_head *ocfs2_bread(struct inode *inode,
                                int block, int *err, int reada)
{
        struct buffer_head *bh = NULL;
        int tmperr;
        u64 p_blkno;
        int readflags = OCFS2_BH_CACHED;

        if (reada)
                readflags |= OCFS2_BH_READAHEAD;

        if (((u64)block << inode->i_sb->s_blocksize_bits) >=
            i_size_read(inode)) {
                BUG_ON(!reada);
                return NULL;
        }

        tmperr = ocfs2_extent_map_get_blocks(inode, block, &p_blkno, NULL,
                                             NULL);
        if (tmperr < 0) {
                mlog_errno(tmperr);
                goto fail;
        }

        tmperr = ocfs2_read_block(OCFS2_SB(inode->i_sb), p_blkno, &bh,
                                  readflags, inode);
        if (tmperr < 0)
                goto fail;

        tmperr = 0;

        *err = 0;
        return bh;

fail:
        if (bh) {
                brelse(bh);
                bh = NULL;
        }
        *err = -EIO;
        return NULL;
}

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

        mlog_entry("(inode = 0x%p, ino = %llu)\n", inode,
                   inode ? (unsigned long long)OCFS2_I(inode)->ip_blkno : 0ULL);

        if (!inode) {
                mlog(0, "eep, no inode!\n");
                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);
                mlog(0, "inode deleted!\n");
                status = -ENOENT;
                goto bail;
        }
        spin_unlock(&OCFS2_I(inode)->ip_lock);

        /* Let ocfs2_meta_lock do the work of updating our struct
         * inode for us. */
        status = ocfs2_meta_lock(inode, NULL, 0);
        if (status < 0) {
                if (status != -ENOENT)
                        mlog_errno(status);
                goto bail;
        }
        ocfs2_meta_unlock(inode, 0);
bail:
        mlog_exit(status);

        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;

        mlog_entry("(inode %llu)\n",
                   (unsigned long long)OCFS2_I(inode)->ip_blkno);

        status = ocfs2_journal_access(handle, 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);
        fe->i_attr = cpu_to_le32(OCFS2_I(inode)->ip_attr);
        spin_unlock(&OCFS2_I(inode)->ip_lock);

        fe->i_size = cpu_to_le64(i_size_read(inode));
        fe->i_links_count = cpu_to_le16(inode->i_nlink);
        fe->i_uid = cpu_to_le32(inode->i_uid);
        fe->i_gid = cpu_to_le32(inode->i_gid);
        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);

        status = ocfs2_journal_dirty(handle, bh);
        if (status < 0)
                mlog_errno(status);

        status = 0;
leave:

        mlog_exit(status);
        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_set_inode_flags(inode);
        i_size_write(inode, le64_to_cpu(fe->i_size));
        inode->i_nlink = le16_to_cpu(fe->i_links_count);
        inode->i_uid = le32_to_cpu(fe->i_uid);
        inode->i_gid = 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_align_bytes_to_sectors(i_size_read(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);
}