journal.c

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/* -*- mode: c; c-basic-offset: 8; -*-
 * vim: noexpandtab sw=8 ts=8 sts=0:
 *
 * journal.c
 *
 * Defines functions of journalling api
 *
 * Copyright (C) 2003, 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/kthread.h>
#include <linux/time.h>
#include <linux/random.h>

#include <cluster/masklog.h>

#include "ocfs2.h"

#include "alloc.h"
#include "blockcheck.h"
#include "dir.h"
#include "dlmglue.h"
#include "extent_map.h"
#include "heartbeat.h"
#include "inode.h"
#include "journal.h"
#include "localalloc.h"
#include "slot_map.h"
#include "super.h"
#include "sysfile.h"
#include "uptodate.h"
#include "quota.h"

#include "buffer_head_io.h"
#include "ocfs2_trace.h"

DEFINE_SPINLOCK(trans_inc_lock);

#define ORPHAN_SCAN_SCHEDULE_TIMEOUT 300000

static int ocfs2_force_read_journal(struct inode *inode);
static int ocfs2_recover_node(struct ocfs2_super *osb,
                  int node_num, int slot_num);
static int __ocfs2_recovery_thread(void *arg);
static int ocfs2_commit_cache(struct ocfs2_super *osb);
static int __ocfs2_wait_on_mount(struct ocfs2_super *osb, int quota);
static int ocfs2_journal_toggle_dirty(struct ocfs2_super *osb,
                      int dirty, int replayed);
static int ocfs2_trylock_journal(struct ocfs2_super *osb,
                 int slot_num);
static int ocfs2_recover_orphans(struct ocfs2_super *osb,
                 int slot);
static int ocfs2_commit_thread(void *arg);
static void ocfs2_queue_recovery_completion(struct ocfs2_journal *journal,
                        int slot_num,
                        struct ocfs2_dinode *la_dinode,
                        struct ocfs2_dinode *tl_dinode,
                        struct ocfs2_quota_recovery *qrec);

static inline int ocfs2_wait_on_mount(struct ocfs2_super *osb)
{
    return __ocfs2_wait_on_mount(osb, 0);
}

static inline int ocfs2_wait_on_quotas(struct ocfs2_super *osb)
{
    return __ocfs2_wait_on_mount(osb, 1);
}

/*
 * This replay_map is to track online/offline slots, so we could recover
 * offline slots during recovery and mount
 */

enum ocfs2_replay_state {
    REPLAY_UNNEEDED = 0,    /* Replay is not needed, so ignore this map */
    REPLAY_NEEDED,      /* Replay slots marked in rm_replay_slots */
    REPLAY_DONE         /* Replay was already queued */
};

struct ocfs2_replay_map {
    unsigned int rm_slots;
    enum ocfs2_replay_state rm_state;
    unsigned char rm_replay_slots[0];
};

void ocfs2_replay_map_set_state(struct ocfs2_super *osb, int state)
{
    if (!osb->replay_map)
        return;

    /* If we've already queued the replay, we don't have any more to do */
    if (osb->replay_map->rm_state == REPLAY_DONE)
        return;

    osb->replay_map->rm_state = state;
}

int ocfs2_compute_replay_slots(struct ocfs2_super *osb)
{
    struct ocfs2_replay_map *replay_map;
    int i, node_num;

    /* If replay map is already set, we don't do it again */
    if (osb->replay_map)
        return 0;

    replay_map = kzalloc(sizeof(struct ocfs2_replay_map) +
                 (osb->max_slots * sizeof(char)), GFP_KERNEL);

    if (!replay_map) {
        mlog_errno(-ENOMEM);
        return -ENOMEM;
    }

    spin_lock(&osb->osb_lock);

    replay_map->rm_slots = osb->max_slots;
    replay_map->rm_state = REPLAY_UNNEEDED;

    /* set rm_replay_slots for offline slot(s) */
    for (i = 0; i < replay_map->rm_slots; i++) {
        if (ocfs2_slot_to_node_num_locked(osb, i, &node_num) == -ENOENT)
            replay_map->rm_replay_slots[i] = 1;
    }

    osb->replay_map = replay_map;
    spin_unlock(&osb->osb_lock);
    return 0;
}

void ocfs2_queue_replay_slots(struct ocfs2_super *osb)
{
    struct ocfs2_replay_map *replay_map = osb->replay_map;
    int i;

    if (!replay_map)
        return;

    if (replay_map->rm_state != REPLAY_NEEDED)
        return;

    for (i = 0; i < replay_map->rm_slots; i++)
        if (replay_map->rm_replay_slots[i])
            ocfs2_queue_recovery_completion(osb->journal, i, NULL,
                            NULL, NULL);
    replay_map->rm_state = REPLAY_DONE;
}

void ocfs2_free_replay_slots(struct ocfs2_super *osb)
{
    struct ocfs2_replay_map *replay_map = osb->replay_map;

    if (!osb->replay_map)
        return;

    kfree(replay_map);
    osb->replay_map = NULL;
}

int ocfs2_recovery_init(struct ocfs2_super *osb)
{
    struct ocfs2_recovery_map *rm;

    mutex_init(&osb->recovery_lock);
    osb->disable_recovery = 0;
    osb->recovery_thread_task = NULL;
    init_waitqueue_head(&osb->recovery_event);

    rm = kzalloc(sizeof(struct ocfs2_recovery_map) +
             osb->max_slots * sizeof(unsigned int),
             GFP_KERNEL);
    if (!rm) {
        mlog_errno(-ENOMEM);
        return -ENOMEM;
    }

    rm->rm_entries = (unsigned int *)((char *)rm +
                      sizeof(struct ocfs2_recovery_map));
    osb->recovery_map = rm;

    return 0;
}

/* we can't grab the goofy sem lock from inside wait_event, so we use
 * memory barriers to make sure that we'll see the null task before
 * being woken up */
static int ocfs2_recovery_thread_running(struct ocfs2_super *osb)
{
    mb();
    return osb->recovery_thread_task != NULL;
}

void ocfs2_recovery_exit(struct ocfs2_super *osb)
{
    struct ocfs2_recovery_map *rm;

    /* disable any new recovery threads and wait for any currently
     * running ones to exit. Do this before setting the vol_state. */
    mutex_lock(&osb->recovery_lock);
    osb->disable_recovery = 1;
    mutex_unlock(&osb->recovery_lock);
    wait_event(osb->recovery_event, !ocfs2_recovery_thread_running(osb));

    /* At this point, we know that no more recovery threads can be
     * launched, so wait for any recovery completion work to
     * complete. */
    flush_workqueue(ocfs2_wq);

    /*
     * Now that recovery is shut down, and the osb is about to be
     * freed,  the osb_lock is not taken here.
     */
    rm = osb->recovery_map;
    /* XXX: Should we bug if there are dirty entries? */

    kfree(rm);
}

static int __ocfs2_recovery_map_test(struct ocfs2_super *osb,
                     unsigned int node_num)
{
    int i;
    struct ocfs2_recovery_map *rm = osb->recovery_map;

    assert_spin_locked(&osb->osb_lock);

    for (i = 0; i < rm->rm_used; i++) {
        if (rm->rm_entries[i] == node_num)
            return 1;
    }

    return 0;
}

/* Behaves like test-and-set.  Returns the previous value */
static int ocfs2_recovery_map_set(struct ocfs2_super *osb,
                  unsigned int node_num)
{
    struct ocfs2_recovery_map *rm = osb->recovery_map;

    spin_lock(&osb->osb_lock);
    if (__ocfs2_recovery_map_test(osb, node_num)) {
        spin_unlock(&osb->osb_lock);
        return 1;
    }

    /* XXX: Can this be exploited? Not from o2dlm... */
    BUG_ON(rm->rm_used >= osb->max_slots);

    rm->rm_entries[rm->rm_used] = node_num;
    rm->rm_used++;
    spin_unlock(&osb->osb_lock);

    return 0;
}

static void ocfs2_recovery_map_clear(struct ocfs2_super *osb,
                     unsigned int node_num)
{
    int i;
    struct ocfs2_recovery_map *rm = osb->recovery_map;

    spin_lock(&osb->osb_lock);

    for (i = 0; i < rm->rm_used; i++) {
        if (rm->rm_entries[i] == node_num)
            break;
    }

    if (i < rm->rm_used) {
        /* XXX: be careful with the pointer math */
        memmove(&(rm->rm_entries[i]), &(rm->rm_entries[i + 1]),
            (rm->rm_used - i - 1) * sizeof(unsigned int));
        rm->rm_used--;
    }

    spin_unlock(&osb->osb_lock);
}

static int ocfs2_commit_cache(struct ocfs2_super *osb)
{
    int status = 0;
    unsigned int flushed;
    struct ocfs2_journal *journal = NULL;

    journal = osb->journal;

    /* Flush all pending commits and checkpoint the journal. */
    down_write(&journal->j_trans_barrier);

    flushed = atomic_read(&journal->j_num_trans);
    trace_ocfs2_commit_cache_begin(flushed);
    if (flushed == 0) {
        up_write(&journal->j_trans_barrier);
        goto finally;
    }

    jbd2_journal_lock_updates(journal->j_journal);
    status = jbd2_journal_flush(journal->j_journal);
    jbd2_journal_unlock_updates(journal->j_journal);
    if (status < 0) {
        up_write(&journal->j_trans_barrier);
        mlog_errno(status);
        goto finally;
    }

    ocfs2_inc_trans_id(journal);

    flushed = atomic_read(&journal->j_num_trans);
    atomic_set(&journal->j_num_trans, 0);
    up_write(&journal->j_trans_barrier);

    trace_ocfs2_commit_cache_end(journal->j_trans_id, flushed);

    ocfs2_wake_downconvert_thread(osb);
    wake_up(&journal->j_checkpointed);
finally:
    return status;
}

handle_t *ocfs2_start_trans(struct ocfs2_super *osb, int max_buffs)
{
    journal_t *journal = osb->journal->j_journal;
    handle_t *handle;

    BUG_ON(!osb || !osb->journal->j_journal);

    if (ocfs2_is_hard_readonly(osb))
        return ERR_PTR(-EROFS);

    BUG_ON(osb->journal->j_state == OCFS2_JOURNAL_FREE);
    BUG_ON(max_buffs <= 0);

    /* Nested transaction? Just return the handle... */
    if (journal_current_handle())
        return jbd2_journal_start(journal, max_buffs);

    sb_start_intwrite(osb->sb);

    down_read(&osb->journal->j_trans_barrier);

    handle = jbd2_journal_start(journal, max_buffs);
    if (IS_ERR(handle)) {
        up_read(&osb->journal->j_trans_barrier);
        sb_end_intwrite(osb->sb);

        mlog_errno(PTR_ERR(handle));

        if (is_journal_aborted(journal)) {
            ocfs2_abort(osb->sb, "Detected aborted journal");
            handle = ERR_PTR(-EROFS);
        }
    } else {
        if (!ocfs2_mount_local(osb))
            atomic_inc(&(osb->journal->j_num_trans));
    }

    return handle;
}

int ocfs2_commit_trans(struct ocfs2_super *osb,
               handle_t *handle)
{
    int ret, nested;
    struct ocfs2_journal *journal = osb->journal;

    BUG_ON(!handle);

    nested = handle->h_ref > 1;
    ret = jbd2_journal_stop(handle);
    if (ret < 0)
        mlog_errno(ret);

    if (!nested) {
        up_read(&journal->j_trans_barrier);
        sb_end_intwrite(osb->sb);
    }

    return ret;
}

/*
 * 'nblocks' is what you want to add to the current transaction.
 *
 * This might call jbd2_journal_restart() which will commit dirty buffers
 * and then restart the transaction. Before calling
 * ocfs2_extend_trans(), any changed blocks should have been
 * dirtied. After calling it, all blocks which need to be changed must
 * go through another set of journal_access/journal_dirty calls.
 *
 * WARNING: This will not release any semaphores or disk locks taken
 * during the transaction, so make sure they were taken *before*
 * start_trans or we'll have ordering deadlocks.
 *
 * WARNING2: Note that we do *not* drop j_trans_barrier here. This is
 * good because transaction ids haven't yet been recorded on the
 * cluster locks associated with this handle.
 */
int ocfs2_extend_trans(handle_t *handle, int nblocks)
{
    int status, old_nblocks;

    BUG_ON(!handle);
    BUG_ON(nblocks < 0);

    if (!nblocks)
        return 0;

    old_nblocks = handle->h_buffer_credits;

    trace_ocfs2_extend_trans(old_nblocks, nblocks);

#ifdef CONFIG_OCFS2_DEBUG_FS
    status = 1;
#else
    status = jbd2_journal_extend(handle, nblocks);
    if (status < 0) {
        mlog_errno(status);
        goto bail;
    }
#endif

    if (status > 0) {
        trace_ocfs2_extend_trans_restart(old_nblocks + nblocks);
        status = jbd2_journal_restart(handle,
                          old_nblocks + nblocks);
        if (status < 0) {
            mlog_errno(status);
            goto bail;
        }
    }

    status = 0;
bail:
    return status;
}

struct ocfs2_triggers {
    struct jbd2_buffer_trigger_type ot_triggers;
    int             ot_offset;
};

static inline struct ocfs2_triggers *to_ocfs2_trigger(struct jbd2_buffer_trigger_type *triggers)
{
    return container_of(triggers, struct ocfs2_triggers, ot_triggers);
}

static void ocfs2_frozen_trigger(struct jbd2_buffer_trigger_type *triggers,
                 struct buffer_head *bh,
                 void *data, size_t size)
{
    struct ocfs2_triggers *ot = to_ocfs2_trigger(triggers);

    /*
     * We aren't guaranteed to have the superblock here, so we
     * must unconditionally compute the ecc data.
     * __ocfs2_journal_access() will only set the triggers if
     * metaecc is enabled.
     */
    ocfs2_block_check_compute(data, size, data + ot->ot_offset);
}

/*
 * Quota blocks have their own trigger because the struct ocfs2_block_check
 * offset depends on the blocksize.
 */
static void ocfs2_dq_frozen_trigger(struct jbd2_buffer_trigger_type *triggers,
                 struct buffer_head *bh,
                 void *data, size_t size)
{
    struct ocfs2_disk_dqtrailer *dqt =
        ocfs2_block_dqtrailer(size, data);

    /*
     * We aren't guaranteed to have the superblock here, so we
     * must unconditionally compute the ecc data.
     * __ocfs2_journal_access() will only set the triggers if
     * metaecc is enabled.
     */
    ocfs2_block_check_compute(data, size, &dqt->dq_check);
}

/*
 * Directory blocks also have their own trigger because the
 * struct ocfs2_block_check offset depends on the blocksize.
 */
static void ocfs2_db_frozen_trigger(struct jbd2_buffer_trigger_type *triggers,
                 struct buffer_head *bh,
                 void *data, size_t size)
{
    struct ocfs2_dir_block_trailer *trailer =
        ocfs2_dir_trailer_from_size(size, data);

    /*
     * We aren't guaranteed to have the superblock here, so we
     * must unconditionally compute the ecc data.
     * __ocfs2_journal_access() will only set the triggers if
     * metaecc is enabled.
     */
    ocfs2_block_check_compute(data, size, &trailer->db_check);
}

static void ocfs2_abort_trigger(struct jbd2_buffer_trigger_type *triggers,
                struct buffer_head *bh)
{
    mlog(ML_ERROR,
         "ocfs2_abort_trigger called by JBD2.  bh = 0x%lx, "
         "bh->b_blocknr = %llu\n",
         (unsigned long)bh,
         (unsigned long long)bh->b_blocknr);

    /* We aren't guaranteed to have the superblock here - but if we
     * don't, it'll just crash. */
    ocfs2_error(bh->b_assoc_map->host->i_sb,
            "JBD2 has aborted our journal, ocfs2 cannot continue\n");
}

static struct ocfs2_triggers di_triggers = {
    .ot_triggers = {
        .t_frozen = ocfs2_frozen_trigger,
        .t_abort = ocfs2_abort_trigger,
    },
    .ot_offset  = offsetof(struct ocfs2_dinode, i_check),
};

static struct ocfs2_triggers eb_triggers = {
    .ot_triggers = {
        .t_frozen = ocfs2_frozen_trigger,
        .t_abort = ocfs2_abort_trigger,
    },
    .ot_offset  = offsetof(struct ocfs2_extent_block, h_check),
};

static struct ocfs2_triggers rb_triggers = {
    .ot_triggers = {
        .t_frozen = ocfs2_frozen_trigger,
        .t_abort = ocfs2_abort_trigger,
    },
    .ot_offset  = offsetof(struct ocfs2_refcount_block, rf_check),
};

static struct ocfs2_triggers gd_triggers = {
    .ot_triggers = {
        .t_frozen = ocfs2_frozen_trigger,
        .t_abort = ocfs2_abort_trigger,
    },
    .ot_offset  = offsetof(struct ocfs2_group_desc, bg_check),
};

static struct ocfs2_triggers db_triggers = {
    .ot_triggers = {
        .t_frozen = ocfs2_db_frozen_trigger,
        .t_abort = ocfs2_abort_trigger,
    },
};

static struct ocfs2_triggers xb_triggers = {
    .ot_triggers = {
        .t_frozen = ocfs2_frozen_trigger,
        .t_abort = ocfs2_abort_trigger,
    },
    .ot_offset  = offsetof(struct ocfs2_xattr_block, xb_check),
};

static struct ocfs2_triggers dq_triggers = {
    .ot_triggers = {
        .t_frozen = ocfs2_dq_frozen_trigger,
        .t_abort = ocfs2_abort_trigger,
    },
};

static struct ocfs2_triggers dr_triggers = {
    .ot_triggers = {
        .t_frozen = ocfs2_frozen_trigger,
        .t_abort = ocfs2_abort_trigger,
    },
    .ot_offset  = offsetof(struct ocfs2_dx_root_block, dr_check),
};

static struct ocfs2_triggers dl_triggers = {
    .ot_triggers = {
        .t_frozen = ocfs2_frozen_trigger,
        .t_abort = ocfs2_abort_trigger,
    },
    .ot_offset  = offsetof(struct ocfs2_dx_leaf, dl_check),
};

static int __ocfs2_journal_access(handle_t *handle,
                  struct ocfs2_caching_info *ci,
                  struct buffer_head *bh,
                  struct ocfs2_triggers *triggers,
                  int type)
{
    int status;
    struct ocfs2_super *osb =
        OCFS2_SB(ocfs2_metadata_cache_get_super(ci));

    BUG_ON(!ci || !ci->ci_ops);
    BUG_ON(!handle);
    BUG_ON(!bh);

    trace_ocfs2_journal_access(
        (unsigned long long)ocfs2_metadata_cache_owner(ci),
        (unsigned long long)bh->b_blocknr, type, bh->b_size);

    /* we can safely remove this assertion after testing. */
    if (!buffer_uptodate(bh)) {
        mlog(ML_ERROR, "giving me a buffer that's not uptodate!\n");
        mlog(ML_ERROR, "b_blocknr=%llu\n",
             (unsigned long long)bh->b_blocknr);
        BUG();
    }

    /* Set the current transaction information on the ci so
     * that the locking code knows whether it can drop it's locks
     * on this ci or not. We're protected from the commit
     * thread updating the current transaction id until
     * ocfs2_commit_trans() because ocfs2_start_trans() took
     * j_trans_barrier for us. */
    ocfs2_set_ci_lock_trans(osb->journal, ci);

    ocfs2_metadata_cache_io_lock(ci);
    switch (type) {
    case OCFS2_JOURNAL_ACCESS_CREATE:
    case OCFS2_JOURNAL_ACCESS_WRITE:
        status = jbd2_journal_get_write_access(handle, bh);
        break;

    case OCFS2_JOURNAL_ACCESS_UNDO:
        status = jbd2_journal_get_undo_access(handle, bh);
        break;

    default:
        status = -EINVAL;
        mlog(ML_ERROR, "Unknown access type!\n");
    }
    if (!status && ocfs2_meta_ecc(osb) && triggers)
        jbd2_journal_set_triggers(bh, &triggers->ot_triggers);
    ocfs2_metadata_cache_io_unlock(ci);

    if (status < 0)
        mlog(ML_ERROR, "Error %d getting %d access to buffer!\n",
             status, type);

    return status;
}

int ocfs2_journal_access_di(handle_t *handle, struct ocfs2_caching_info *ci,
                struct buffer_head *bh, int type)
{
    return __ocfs2_journal_access(handle, ci, bh, &di_triggers, type);
}

int ocfs2_journal_access_eb(handle_t *handle, struct ocfs2_caching_info *ci,
                struct buffer_head *bh, int type)
{
    return __ocfs2_journal_access(handle, ci, bh, &eb_triggers, type);
}

int ocfs2_journal_access_rb(handle_t *handle, struct ocfs2_caching_info *ci,
                struct buffer_head *bh, int type)
{
    return __ocfs2_journal_access(handle, ci, bh, &rb_triggers,
                      type);
}

int ocfs2_journal_access_gd(handle_t *handle, struct ocfs2_caching_info *ci,
                struct buffer_head *bh, int type)
{
    return __ocfs2_journal_access(handle, ci, bh, &gd_triggers, type);
}

int ocfs2_journal_access_db(handle_t *handle, struct ocfs2_caching_info *ci,
                struct buffer_head *bh, int type)
{
    return __ocfs2_journal_access(handle, ci, bh, &db_triggers, type);
}

int ocfs2_journal_access_xb(handle_t *handle, struct ocfs2_caching_info *ci,
                struct buffer_head *bh, int type)
{
    return __ocfs2_journal_access(handle, ci, bh, &xb_triggers, type);
}

int ocfs2_journal_access_dq(handle_t *handle, struct ocfs2_caching_info *ci,
                struct buffer_head *bh, int type)
{
    return __ocfs2_journal_access(handle, ci, bh, &dq_triggers, type);
}

int ocfs2_journal_access_dr(handle_t *handle, struct ocfs2_caching_info *ci,
                struct buffer_head *bh, int type)
{
    return __ocfs2_journal_access(handle, ci, bh, &dr_triggers, type);
}

int ocfs2_journal_access_dl(handle_t *handle, struct ocfs2_caching_info *ci,
                struct buffer_head *bh, int type)
{
    return __ocfs2_journal_access(handle, ci, bh, &dl_triggers, type);
}

int ocfs2_journal_access(handle_t *handle, struct ocfs2_caching_info *ci,
             struct buffer_head *bh, int type)
{
    return __ocfs2_journal_access(handle, ci, bh, NULL, type);
}

void ocfs2_journal_dirty(handle_t *handle, struct buffer_head *bh)
{
    int status;

    trace_ocfs2_journal_dirty((unsigned long long)bh->b_blocknr);

    status = jbd2_journal_dirty_metadata(handle, bh);
    BUG_ON(status);
}

#define OCFS2_DEFAULT_COMMIT_INTERVAL   (HZ * JBD2_DEFAULT_MAX_COMMIT_AGE)

void ocfs2_set_journal_params(struct ocfs2_super *osb)
{
    journal_t *journal = osb->journal->j_journal;
    unsigned long commit_interval = OCFS2_DEFAULT_COMMIT_INTERVAL;

    if (osb->osb_commit_interval)
        commit_interval = osb->osb_commit_interval;

    write_lock(&journal->j_state_lock);
    journal->j_commit_interval = commit_interval;
    if (osb->s_mount_opt & OCFS2_MOUNT_BARRIER)
        journal->j_flags |= JBD2_BARRIER;
    else
        journal->j_flags &= ~JBD2_BARRIER;
    write_unlock(&journal->j_state_lock);
}

int ocfs2_journal_init(struct ocfs2_journal *journal, int *dirty)
{
    int status = -1;
    struct inode *inode = NULL; /* the journal inode */
    journal_t *j_journal = NULL;
    struct ocfs2_dinode *di = NULL;
    struct buffer_head *bh = NULL;
    struct ocfs2_super *osb;
    int inode_lock = 0;

    BUG_ON(!journal);

    osb = journal->j_osb;

    /* already have the inode for our journal */
    inode = ocfs2_get_system_file_inode(osb, JOURNAL_SYSTEM_INODE,
                        osb->slot_num);
    if (inode == NULL) {
        status = -EACCES;
        mlog_errno(status);
        goto done;
    }
    if (is_bad_inode(inode)) {
        mlog(ML_ERROR, "access error (bad inode)\n");
        iput(inode);
        inode = NULL;
        status = -EACCES;
        goto done;
    }

    SET_INODE_JOURNAL(inode);
    OCFS2_I(inode)->ip_open_count++;

    /* Skip recovery waits here - journal inode metadata never
     * changes in a live cluster so it can be considered an
     * exception to the rule. */
    status = ocfs2_inode_lock_full(inode, &bh, 1, OCFS2_META_LOCK_RECOVERY);
    if (status < 0) {
        if (status != -ERESTARTSYS)
            mlog(ML_ERROR, "Could not get lock on journal!\n");
        goto done;
    }

    inode_lock = 1;
    di = (struct ocfs2_dinode *)bh->b_data;

    if (inode->i_size <  OCFS2_MIN_JOURNAL_SIZE) {
        mlog(ML_ERROR, "Journal file size (%lld) is too small!\n",
             inode->i_size);
        status = -EINVAL;
        goto done;
    }

    trace_ocfs2_journal_init(inode->i_size,
                 (unsigned long long)inode->i_blocks,
                 OCFS2_I(inode)->ip_clusters);

    /* call the kernels journal init function now */
    j_journal = jbd2_journal_init_inode(inode);
    if (j_journal == NULL) {
        mlog(ML_ERROR, "Linux journal layer error\n");
        status = -EINVAL;
        goto done;
    }

    trace_ocfs2_journal_init_maxlen(j_journal->j_maxlen);

    *dirty = (le32_to_cpu(di->id1.journal1.ij_flags) &
          OCFS2_JOURNAL_DIRTY_FL);

    journal->j_journal = j_journal;
    journal->j_inode = inode;
    journal->j_bh = bh;

    ocfs2_set_journal_params(osb);

    journal->j_state = OCFS2_JOURNAL_LOADED;

    status = 0;
done:
    if (status < 0) {
        if (inode_lock)
            ocfs2_inode_unlock(inode, 1);
        brelse(bh);
        if (inode) {
            OCFS2_I(inode)->ip_open_count--;
            iput(inode);
        }
    }

    return status;
}

static void ocfs2_bump_recovery_generation(struct ocfs2_dinode *di)
{
    le32_add_cpu(&(di->id1.journal1.ij_recovery_generation), 1);
}

static u32 ocfs2_get_recovery_generation(struct ocfs2_dinode *di)
{
    return le32_to_cpu(di->id1.journal1.ij_recovery_generation);
}

static int ocfs2_journal_toggle_dirty(struct ocfs2_super *osb,
                      int dirty, int replayed)
{
    int status;
    unsigned int flags;
    struct ocfs2_journal *journal = osb->journal;
    struct buffer_head *bh = journal->j_bh;
    struct ocfs2_dinode *fe;

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

    /* The journal bh on the osb always comes from ocfs2_journal_init()
     * and was validated there inside ocfs2_inode_lock_full().  It's a
     * code bug if we mess it up. */
    BUG_ON(!OCFS2_IS_VALID_DINODE(fe));

    flags = le32_to_cpu(fe->id1.journal1.ij_flags);
    if (dirty)
        flags |= OCFS2_JOURNAL_DIRTY_FL;
    else
        flags &= ~OCFS2_JOURNAL_DIRTY_FL;
    fe->id1.journal1.ij_flags = cpu_to_le32(flags);

    if (replayed)
        ocfs2_bump_recovery_generation(fe);

    ocfs2_compute_meta_ecc(osb->sb, bh->b_data, &fe->i_check);
    status = ocfs2_write_block(osb, bh, INODE_CACHE(journal->j_inode));
    if (status < 0)
        mlog_errno(status);

    return status;
}

/*
 * If the journal has been kmalloc'd it needs to be freed after this
 * call.
 */
void ocfs2_journal_shutdown(struct ocfs2_super *osb)
{
    struct ocfs2_journal *journal = NULL;
    int status = 0;
    struct inode *inode = NULL;
    int num_running_trans = 0;

    BUG_ON(!osb);

    journal = osb->journal;
    if (!journal)
        goto done;

    inode = journal->j_inode;

    if (journal->j_state != OCFS2_JOURNAL_LOADED)
        goto done;

    /* need to inc inode use count - jbd2_journal_destroy will iput. */
    if (!igrab(inode))
        BUG();

    num_running_trans = atomic_read(&(osb->journal->j_num_trans));
    trace_ocfs2_journal_shutdown(num_running_trans);

    /* Do a commit_cache here. It will flush our journal, *and*
     * release any locks that are still held.
     * set the SHUTDOWN flag and release the trans lock.
     * the commit thread will take the trans lock for us below. */
    journal->j_state = OCFS2_JOURNAL_IN_SHUTDOWN;

    /* The OCFS2_JOURNAL_IN_SHUTDOWN will signal to commit_cache to not
     * drop the trans_lock (which we want to hold until we
     * completely destroy the journal. */
    if (osb->commit_task) {
        /* Wait for the commit thread */
        trace_ocfs2_journal_shutdown_wait(osb->commit_task);
        kthread_stop(osb->commit_task);
        osb->commit_task = NULL;
    }

    BUG_ON(atomic_read(&(osb->journal->j_num_trans)) != 0);

    if (ocfs2_mount_local(osb)) {
        jbd2_journal_lock_updates(journal->j_journal);
        status = jbd2_journal_flush(journal->j_journal);
        jbd2_journal_unlock_updates(journal->j_journal);
        if (status < 0)
            mlog_errno(status);
    }

    if (status == 0) {
        /*
         * Do not toggle if flush was unsuccessful otherwise
         * will leave dirty metadata in a "clean" journal
         */
        status = ocfs2_journal_toggle_dirty(osb, 0, 0);
        if (status < 0)
            mlog_errno(status);
    }

    /* Shutdown the kernel journal system */
    jbd2_journal_destroy(journal->j_journal);
    journal->j_journal = NULL;

    OCFS2_I(inode)->ip_open_count--;

    /* unlock our journal */
    ocfs2_inode_unlock(inode, 1);

    brelse(journal->j_bh);
    journal->j_bh = NULL;

    journal->j_state = OCFS2_JOURNAL_FREE;

//  up_write(&journal->j_trans_barrier);
done:
    if (inode)
        iput(inode);
}

static void ocfs2_clear_journal_error(struct super_block *sb,
                      journal_t *journal,
                      int slot)
{
    int olderr;

    olderr = jbd2_journal_errno(journal);
    if (olderr) {
        mlog(ML_ERROR, "File system error %d recorded in "
             "journal %u.\n", olderr, slot);
        mlog(ML_ERROR, "File system on device %s needs checking.\n",
             sb->s_id);

        jbd2_journal_ack_err(journal);
        jbd2_journal_clear_err(journal);
    }
}

int ocfs2_journal_load(struct ocfs2_journal *journal, int local, int replayed)
{
    int status = 0;
    struct ocfs2_super *osb;

    BUG_ON(!journal);

    osb = journal->j_osb;

    status = jbd2_journal_load(journal->j_journal);
    if (status < 0) {
        mlog(ML_ERROR, "Failed to load journal!\n");
        goto done;
    }

    ocfs2_clear_journal_error(osb->sb, journal->j_journal, osb->slot_num);

    status = ocfs2_journal_toggle_dirty(osb, 1, replayed);
    if (status < 0) {
        mlog_errno(status);
        goto done;
    }

    /* Launch the commit thread */
    if (!local) {
        osb->commit_task = kthread_run(ocfs2_commit_thread, osb,
                           "ocfs2cmt");
        if (IS_ERR(osb->commit_task)) {
            status = PTR_ERR(osb->commit_task);
            osb->commit_task = NULL;
            mlog(ML_ERROR, "unable to launch ocfs2commit thread, "
                 "error=%d", status);
            goto done;
        }
    } else
        osb->commit_task = NULL;

done:
    return status;
}


/* 'full' flag tells us whether we clear out all blocks or if we just
 * mark the journal clean */
int ocfs2_journal_wipe(struct ocfs2_journal *journal, int full)
{
    int status;

    BUG_ON(!journal);

    status = jbd2_journal_wipe(journal->j_journal, full);
    if (status < 0) {
        mlog_errno(status);
        goto bail;
    }

    status = ocfs2_journal_toggle_dirty(journal->j_osb, 0, 0);
    if (status < 0)
        mlog_errno(status);

bail:
    return status;
}

static int ocfs2_recovery_completed(struct ocfs2_super *osb)
{
    int empty;
    struct ocfs2_recovery_map *rm = osb->recovery_map;

    spin_lock(&osb->osb_lock);
    empty = (rm->rm_used == 0);
    spin_unlock(&osb->osb_lock);

    return empty;
}

void ocfs2_wait_for_recovery(struct ocfs2_super *osb)
{
    wait_event(osb->recovery_event, ocfs2_recovery_completed(osb));
}

/*
 * JBD Might read a cached version of another nodes journal file. We
 * don't want this as this file changes often and we get no
 * notification on those changes. The only way to be sure that we've
 * got the most up to date version of those blocks then is to force
 * read them off disk. Just searching through the buffer cache won't
 * work as there may be pages backing this file which are still marked
 * up to date. We know things can't change on this file underneath us
 * as we have the lock by now :)
 */
static int ocfs2_force_read_journal(struct inode *inode)
{
    int status = 0;
    int i;
    u64 v_blkno, p_blkno, p_blocks, num_blocks;
#define CONCURRENT_JOURNAL_FILL 32ULL
    struct buffer_head *bhs[CONCURRENT_JOURNAL_FILL];

    memset(bhs, 0, sizeof(struct buffer_head *) * CONCURRENT_JOURNAL_FILL);

    num_blocks = ocfs2_blocks_for_bytes(inode->i_sb, inode->i_size);
    v_blkno = 0;
    while (v_blkno < num_blocks) {
        status = ocfs2_extent_map_get_blocks(inode, v_blkno,
                             &p_blkno, &p_blocks, NULL);
        if (status < 0) {
            mlog_errno(status);
            goto bail;
        }

        if (p_blocks > CONCURRENT_JOURNAL_FILL)
            p_blocks = CONCURRENT_JOURNAL_FILL;

        /* We are reading journal data which should not
         * be put in the uptodate cache */
        status = ocfs2_read_blocks_sync(OCFS2_SB(inode->i_sb),
                        p_blkno, p_blocks, bhs);
        if (status < 0) {
            mlog_errno(status);
            goto bail;
        }

        for(i = 0; i < p_blocks; i++) {
            brelse(bhs[i]);
            bhs[i] = NULL;
        }

        v_blkno += p_blocks;
    }

bail:
    for(i = 0; i < CONCURRENT_JOURNAL_FILL; i++)
        brelse(bhs[i]);
    return status;
}

struct ocfs2_la_recovery_item {
    struct list_head    lri_list;
    int         lri_slot;
    struct ocfs2_dinode *lri_la_dinode;
    struct ocfs2_dinode *lri_tl_dinode;
    struct ocfs2_quota_recovery *lri_qrec;
};

/* Does the second half of the recovery process. By this point, the
 * node is marked clean and can actually be considered recovered,
 * hence it's no longer in the recovery map, but there's still some
 * cleanup we can do which shouldn't happen within the recovery thread
 * as locking in that context becomes very difficult if we are to take
 * recovering nodes into account.
 *
 * NOTE: This function can and will sleep on recovery of other nodes
 * during cluster locking, just like any other ocfs2 process.
 */
void ocfs2_complete_recovery(struct work_struct *work)
{
    int ret = 0;
    struct ocfs2_journal *journal =
        container_of(work, struct ocfs2_journal, j_recovery_work);
    struct ocfs2_super *osb = journal->j_osb;
    struct ocfs2_dinode *la_dinode, *tl_dinode;
    struct ocfs2_la_recovery_item *item, *n;
    struct ocfs2_quota_recovery *qrec;
    LIST_HEAD(tmp_la_list);

    trace_ocfs2_complete_recovery(
        (unsigned long long)OCFS2_I(journal->j_inode)->ip_blkno);

    spin_lock(&journal->j_lock);
    list_splice_init(&journal->j_la_cleanups, &tmp_la_list);
    spin_unlock(&journal->j_lock);

    list_for_each_entry_safe(item, n, &tmp_la_list, lri_list) {
        list_del_init(&item->lri_list);

        ocfs2_wait_on_quotas(osb);

        la_dinode = item->lri_la_dinode;
        tl_dinode = item->lri_tl_dinode;
        qrec = item->lri_qrec;

        trace_ocfs2_complete_recovery_slot(item->lri_slot,
            la_dinode ? le64_to_cpu(la_dinode->i_blkno) : 0,
            tl_dinode ? le64_to_cpu(tl_dinode->i_blkno) : 0,
            qrec);

        if (la_dinode) {
            ret = ocfs2_complete_local_alloc_recovery(osb,
                                  la_dinode);
            if (ret < 0)
                mlog_errno(ret);

            kfree(la_dinode);
        }

        if (tl_dinode) {
            ret = ocfs2_complete_truncate_log_recovery(osb,
                                   tl_dinode);
            if (ret < 0)
                mlog_errno(ret);

            kfree(tl_dinode);
        }

        ret = ocfs2_recover_orphans(osb, item->lri_slot);
        if (ret < 0)
            mlog_errno(ret);

        if (qrec) {
            ret = ocfs2_finish_quota_recovery(osb, qrec,
                              item->lri_slot);
            if (ret < 0)
                mlog_errno(ret);
            /* Recovery info is already freed now */
        }

        kfree(item);
    }

    trace_ocfs2_complete_recovery_end(ret);
}

/* NOTE: This function always eats your references to la_dinode and
 * tl_dinode, either manually on error, or by passing them to
 * ocfs2_complete_recovery */
static void ocfs2_queue_recovery_completion(struct ocfs2_journal *journal,
                        int slot_num,
                        struct ocfs2_dinode *la_dinode,
                        struct ocfs2_dinode *tl_dinode,
                        struct ocfs2_quota_recovery *qrec)
{
    struct ocfs2_la_recovery_item *item;

    item = kmalloc(sizeof(struct ocfs2_la_recovery_item), GFP_NOFS);
    if (!item) {
        /* Though we wish to avoid it, we are in fact safe in
         * skipping local alloc cleanup as fsck.ocfs2 is more
         * than capable of reclaiming unused space. */
        if (la_dinode)
            kfree(la_dinode);

        if (tl_dinode)
            kfree(tl_dinode);

        if (qrec)
            ocfs2_free_quota_recovery(qrec);

        mlog_errno(-ENOMEM);
        return;
    }

    INIT_LIST_HEAD(&item->lri_list);
    item->lri_la_dinode = la_dinode;
    item->lri_slot = slot_num;
    item->lri_tl_dinode = tl_dinode;
    item->lri_qrec = qrec;

    spin_lock(&journal->j_lock);
    list_add_tail(&item->lri_list, &journal->j_la_cleanups);
    queue_work(ocfs2_wq, &journal->j_recovery_work);
    spin_unlock(&journal->j_lock);
}

/* Called by the mount code to queue recovery the last part of
 * recovery for it's own and offline slot(s). */
void ocfs2_complete_mount_recovery(struct ocfs2_super *osb)
{
    struct ocfs2_journal *journal = osb->journal;

    if (ocfs2_is_hard_readonly(osb))
        return;

    /* No need to queue up our truncate_log as regular cleanup will catch
     * that */
    ocfs2_queue_recovery_completion(journal, osb->slot_num,
                    osb->local_alloc_copy, NULL, NULL);
    ocfs2_schedule_truncate_log_flush(osb, 0);

    osb->local_alloc_copy = NULL;
    osb->dirty = 0;

    /* queue to recover orphan slots for all offline slots */
    ocfs2_replay_map_set_state(osb, REPLAY_NEEDED);
    ocfs2_queue_replay_slots(osb);
    ocfs2_free_replay_slots(osb);
}

void ocfs2_complete_quota_recovery(struct ocfs2_super *osb)
{
    if (osb->quota_rec) {
        ocfs2_queue_recovery_completion(osb->journal,
                        osb->slot_num,
                        NULL,
                        NULL,
                        osb->quota_rec);
        osb->quota_rec = NULL;
    }
}

static int __ocfs2_recovery_thread(void *arg)
{
    int status, node_num, slot_num;
    struct ocfs2_super *osb = arg;
    struct ocfs2_recovery_map *rm = osb->recovery_map;
    int *rm_quota = NULL;
    int rm_quota_used = 0, i;
    struct ocfs2_quota_recovery *qrec;

    status = ocfs2_wait_on_mount(osb);
    if (status < 0) {
        goto bail;
    }

    rm_quota = kzalloc(osb->max_slots * sizeof(int), GFP_NOFS);
    if (!rm_quota) {
        status = -ENOMEM;
        goto bail;
    }
restart:
    status = ocfs2_super_lock(osb, 1);
    if (status < 0) {
        mlog_errno(status);
        goto bail;
    }

    status = ocfs2_compute_replay_slots(osb);
    if (status < 0)
        mlog_errno(status);

    /* queue recovery for our own slot */
    ocfs2_queue_recovery_completion(osb->journal, osb->slot_num, NULL,
                    NULL, NULL);

    spin_lock(&osb->osb_lock);
    while (rm->rm_used) {
        /* It's always safe to remove entry zero, as we won't
         * clear it until ocfs2_recover_node() has succeeded. */
        node_num = rm->rm_entries[0];
        spin_unlock(&osb->osb_lock);
        slot_num = ocfs2_node_num_to_slot(osb, node_num);
        trace_ocfs2_recovery_thread_node(node_num, slot_num);
        if (slot_num == -ENOENT) {
            status = 0;
            goto skip_recovery;
        }

        /* It is a bit subtle with quota recovery. We cannot do it
         * immediately because we have to obtain cluster locks from
         * quota files and we also don't want to just skip it because
         * then quota usage would be out of sync until some node takes
         * the slot. So we remember which nodes need quota recovery
         * and when everything else is done, we recover quotas. */
        for (i = 0; i < rm_quota_used && rm_quota[i] != slot_num; i++);
        if (i == rm_quota_used)
            rm_quota[rm_quota_used++] = slot_num;

        status = ocfs2_recover_node(osb, node_num, slot_num);
skip_recovery:
        if (!status) {
            ocfs2_recovery_map_clear(osb, node_num);
        } else {
            mlog(ML_ERROR,
                 "Error %d recovering node %d on device (%u,%u)!\n",
                 status, node_num,
                 MAJOR(osb->sb->s_dev), MINOR(osb->sb->s_dev));
            mlog(ML_ERROR, "Volume requires unmount.\n");
        }

        spin_lock(&osb->osb_lock);
    }
    spin_unlock(&osb->osb_lock);
    trace_ocfs2_recovery_thread_end(status);

    /* Refresh all journal recovery generations from disk */
    status = ocfs2_check_journals_nolocks(osb);
    status = (status == -EROFS) ? 0 : status;
    if (status < 0)
        mlog_errno(status);

    /* Now it is right time to recover quotas... We have to do this under
     * superblock lock so that no one can start using the slot (and crash)
     * before we recover it */
    for (i = 0; i < rm_quota_used; i++) {
        qrec = ocfs2_begin_quota_recovery(osb, rm_quota[i]);
        if (IS_ERR(qrec)) {
            status = PTR_ERR(qrec);
            mlog_errno(status);
            continue;
        }
        ocfs2_queue_recovery_completion(osb->journal, rm_quota[i],
                        NULL, NULL, qrec);
    }

    ocfs2_super_unlock(osb, 1);

    /* queue recovery for offline slots */
    ocfs2_queue_replay_slots(osb);

bail:
    mutex_lock(&osb->recovery_lock);
    if (!status && !ocfs2_recovery_completed(osb)) {
        mutex_unlock(&osb->recovery_lock);
        goto restart;
    }

    ocfs2_free_replay_slots(osb);
    osb->recovery_thread_task = NULL;
    mb(); /* sync with ocfs2_recovery_thread_running */
    wake_up(&osb->recovery_event);

    mutex_unlock(&osb->recovery_lock);

    if (rm_quota)
        kfree(rm_quota);

    /* no one is callint kthread_stop() for us so the kthread() api
     * requires that we call do_exit().  And it isn't exported, but
     * complete_and_exit() seems to be a minimal wrapper around it. */
    complete_and_exit(NULL, status);
    return status;
}

void ocfs2_recovery_thread(struct ocfs2_super *osb, int node_num)
{
    mutex_lock(&osb->recovery_lock);

    trace_ocfs2_recovery_thread(node_num, osb->node_num,
        osb->disable_recovery, osb->recovery_thread_task,
        osb->disable_recovery ?
        -1 : ocfs2_recovery_map_set(osb, node_num));

    if (osb->disable_recovery)
        goto out;

    if (osb->recovery_thread_task)
        goto out;

    osb->recovery_thread_task =  kthread_run(__ocfs2_recovery_thread, osb,
                         "ocfs2rec");
    if (IS_ERR(osb->recovery_thread_task)) {
        mlog_errno((int)PTR_ERR(osb->recovery_thread_task));
        osb->recovery_thread_task = NULL;
    }

out:
    mutex_unlock(&osb->recovery_lock);
    wake_up(&osb->recovery_event);
}

static int ocfs2_read_journal_inode(struct ocfs2_super *osb,
                    int slot_num,
                    struct buffer_head **bh,
                    struct inode **ret_inode)
{
    int status = -EACCES;
    struct inode *inode = NULL;

    BUG_ON(slot_num >= osb->max_slots);

    inode = ocfs2_get_system_file_inode(osb, JOURNAL_SYSTEM_INODE,
                        slot_num);
    if (!inode || is_bad_inode(inode)) {
        mlog_errno(status);
        goto bail;
    }
    SET_INODE_JOURNAL(inode);

    status = ocfs2_read_inode_block_full(inode, bh, OCFS2_BH_IGNORE_CACHE);
    if (status < 0) {
        mlog_errno(status);
        goto bail;
    }

    status = 0;

bail:
    if (inode) {
        if (status || !ret_inode)
            iput(inode);
        else
            *ret_inode = inode;
    }
    return status;
}

/* Does the actual journal replay and marks the journal inode as
 * clean. Will only replay if the journal inode is marked dirty. */
static int ocfs2_replay_journal(struct ocfs2_super *osb,
                int node_num,
                int slot_num)
{
    int status;
    int got_lock = 0;
    unsigned int flags;
    struct inode *inode = NULL;
    struct ocfs2_dinode *fe;
    journal_t *journal = NULL;
    struct buffer_head *bh = NULL;
    u32 slot_reco_gen;

    status = ocfs2_read_journal_inode(osb, slot_num, &bh, &inode);
    if (status) {
        mlog_errno(status);
        goto done;
    }

    fe = (struct ocfs2_dinode *)bh->b_data;
    slot_reco_gen = ocfs2_get_recovery_generation(fe);
    brelse(bh);
    bh = NULL;

    /*
     * As the fs recovery is asynchronous, there is a small chance that
     * another node mounted (and recovered) the slot before the recovery
     * thread could get the lock. To handle that, we dirty read the journal
     * inode for that slot to get the recovery generation. If it is
     * different than what we expected, the slot has been recovered.
     * If not, it needs recovery.
     */
    if (osb->slot_recovery_generations[slot_num] != slot_reco_gen) {
        trace_ocfs2_replay_journal_recovered(slot_num,
             osb->slot_recovery_generations[slot_num], slot_reco_gen);
        osb->slot_recovery_generations[slot_num] = slot_reco_gen;
        status = -EBUSY;
        goto done;
    }

    /* Continue with recovery as the journal has not yet been recovered */

    status = ocfs2_inode_lock_full(inode, &bh, 1, OCFS2_META_LOCK_RECOVERY);
    if (status < 0) {
        trace_ocfs2_replay_journal_lock_err(status);
        if (status != -ERESTARTSYS)
            mlog(ML_ERROR, "Could not lock journal!\n");
        goto done;
    }
    got_lock = 1;

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

    flags = le32_to_cpu(fe->id1.journal1.ij_flags);
    slot_reco_gen = ocfs2_get_recovery_generation(fe);

    if (!(flags & OCFS2_JOURNAL_DIRTY_FL)) {
        trace_ocfs2_replay_journal_skip(node_num);
        /* Refresh recovery generation for the slot */
        osb->slot_recovery_generations[slot_num] = slot_reco_gen;
        goto done;
    }

    /* we need to run complete recovery for offline orphan slots */
    ocfs2_replay_map_set_state(osb, REPLAY_NEEDED);

    printk(KERN_NOTICE "ocfs2: Begin replay journal (node %d, slot %d) on "\
           "device (%u,%u)\n", node_num, slot_num, MAJOR(osb->sb->s_dev),
           MINOR(osb->sb->s_dev));

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

    status = ocfs2_force_read_journal(inode);
    if (status < 0) {
        mlog_errno(status);
        goto done;
    }

    journal = jbd2_journal_init_inode(inode);
    if (journal == NULL) {
        mlog(ML_ERROR, "Linux journal layer error\n");
        status = -EIO;
        goto done;
    }

    status = jbd2_journal_load(journal);
    if (status < 0) {
        mlog_errno(status);
        if (!igrab(inode))
            BUG();
        jbd2_journal_destroy(journal);
        goto done;
    }

    ocfs2_clear_journal_error(osb->sb, journal, slot_num);

    /* wipe the journal */
    jbd2_journal_lock_updates(journal);
    status = jbd2_journal_flush(journal);
    jbd2_journal_unlock_updates(journal);
    if (status < 0)
        mlog_errno(status);

    /* This will mark the node clean */
    flags = le32_to_cpu(fe->id1.journal1.ij_flags);
    flags &= ~OCFS2_JOURNAL_DIRTY_FL;
    fe->id1.journal1.ij_flags = cpu_to_le32(flags);

    /* Increment recovery generation to indicate successful recovery */
    ocfs2_bump_recovery_generation(fe);
    osb->slot_recovery_generations[slot_num] =
                    ocfs2_get_recovery_generation(fe);

    ocfs2_compute_meta_ecc(osb->sb, bh->b_data, &fe->i_check);
    status = ocfs2_write_block(osb, bh, INODE_CACHE(inode));
    if (status < 0)
        mlog_errno(status);

    if (!igrab(inode))
        BUG();

    jbd2_journal_destroy(journal);

    printk(KERN_NOTICE "ocfs2: End replay journal (node %d, slot %d) on "\
           "device (%u,%u)\n", node_num, slot_num, MAJOR(osb->sb->s_dev),
           MINOR(osb->sb->s_dev));
done:
    /* drop the lock on this nodes journal */
    if (got_lock)
        ocfs2_inode_unlock(inode, 1);

    if (inode)
        iput(inode);

    brelse(bh);

    return status;
}

/*
 * Do the most important parts of node recovery:
 *  - Replay it's journal
 *  - Stamp a clean local allocator file
 *  - Stamp a clean truncate log
 *  - Mark the node clean
 *
 * If this function completes without error, a node in OCFS2 can be
 * said to have been safely recovered. As a result, failure during the
 * second part of a nodes recovery process (local alloc recovery) is
 * far less concerning.
 */
static int ocfs2_recover_node(struct ocfs2_super *osb,
                  int node_num, int slot_num)
{
    int status = 0;
    struct ocfs2_dinode *la_copy = NULL;
    struct ocfs2_dinode *tl_copy = NULL;

    trace_ocfs2_recover_node(node_num, slot_num, osb->node_num);

    /* Should not ever be called to recover ourselves -- in that
     * case we should've called ocfs2_journal_load instead. */
    BUG_ON(osb->node_num == node_num);

    status = ocfs2_replay_journal(osb, node_num, slot_num);
    if (status < 0) {
        if (status == -EBUSY) {
            trace_ocfs2_recover_node_skip(slot_num, node_num);
            status = 0;
            goto done;
        }
        mlog_errno(status);
        goto done;
    }

    /* Stamp a clean local alloc file AFTER recovering the journal... */
    status = ocfs2_begin_local_alloc_recovery(osb, slot_num, &la_copy);
    if (status < 0) {
        mlog_errno(status);
        goto done;
    }

    /* An error from begin_truncate_log_recovery is not
     * serious enough to warrant halting the rest of
     * recovery. */
    status = ocfs2_begin_truncate_log_recovery(osb, slot_num, &tl_copy);
    if (status < 0)
        mlog_errno(status);

    /* Likewise, this would be a strange but ultimately not so
     * harmful place to get an error... */
    status = ocfs2_clear_slot(osb, slot_num);
    if (status < 0)
        mlog_errno(status);

    /* This will kfree the memory pointed to by la_copy and tl_copy */
    ocfs2_queue_recovery_completion(osb->journal, slot_num, la_copy,
                    tl_copy, NULL);

    status = 0;
done:

    return status;
}

/* Test node liveness by trylocking his journal. If we get the lock,
 * we drop it here. Return 0 if we got the lock, -EAGAIN if node is
 * still alive (we couldn't get the lock) and < 0 on error. */
static int ocfs2_trylock_journal(struct ocfs2_super *osb,
                 int slot_num)
{
    int status, flags;
    struct inode *inode = NULL;

    inode = ocfs2_get_system_file_inode(osb, JOURNAL_SYSTEM_INODE,
                        slot_num);
    if (inode == NULL) {
        mlog(ML_ERROR, "access error\n");
        status = -EACCES;
        goto bail;
    }
    if (is_bad_inode(inode)) {
        mlog(ML_ERROR, "access error (bad inode)\n");
        iput(inode);
        inode = NULL;
        status = -EACCES;
        goto bail;
    }
    SET_INODE_JOURNAL(inode);

    flags = OCFS2_META_LOCK_RECOVERY | OCFS2_META_LOCK_NOQUEUE;
    status = ocfs2_inode_lock_full(inode, NULL, 1, flags);
    if (status < 0) {
        if (status != -EAGAIN)
            mlog_errno(status);
        goto bail;
    }

    ocfs2_inode_unlock(inode, 1);
bail:
    if (inode)
        iput(inode);

    return status;
}

/* Call this underneath ocfs2_super_lock. It also assumes that the
 * slot info struct has been updated from disk. */
int ocfs2_mark_dead_nodes(struct ocfs2_super *osb)
{
    unsigned int node_num;
    int status, i;
    u32 gen;
    struct buffer_head *bh = NULL;
    struct ocfs2_dinode *di;

    /* This is called with the super block cluster lock, so we
     * know that the slot map can't change underneath us. */

    for (i = 0; i < osb->max_slots; i++) {
        /* Read journal inode to get the recovery generation */
        status = ocfs2_read_journal_inode(osb, i, &bh, NULL);
        if (status) {
            mlog_errno(status);
            goto bail;
        }
        di = (struct ocfs2_dinode *)bh->b_data;
        gen = ocfs2_get_recovery_generation(di);
        brelse(bh);
        bh = NULL;

        spin_lock(&osb->osb_lock);
        osb->slot_recovery_generations[i] = gen;

        trace_ocfs2_mark_dead_nodes(i,
                        osb->slot_recovery_generations[i]);

        if (i == osb->slot_num) {
            spin_unlock(&osb->osb_lock);
            continue;
        }

        status = ocfs2_slot_to_node_num_locked(osb, i, &node_num);
        if (status == -ENOENT) {
            spin_unlock(&osb->osb_lock);
            continue;
        }

        if (__ocfs2_recovery_map_test(osb, node_num)) {
            spin_unlock(&osb->osb_lock);
            continue;
        }
        spin_unlock(&osb->osb_lock);

        /* Ok, we have a slot occupied by another node which
         * is not in the recovery map. We trylock his journal
         * file here to test if he's alive. */
        status = ocfs2_trylock_journal(osb, i);
        if (!status) {
            /* Since we're called from mount, we know that
             * the recovery thread can't race us on
             * setting / checking the recovery bits. */
            ocfs2_recovery_thread(osb, node_num);
        } else if ((status < 0) && (status != -EAGAIN)) {
            mlog_errno(status);
            goto bail;
        }
    }

    status = 0;
bail:
    return status;
}

/*
 * Scan timer should get fired every ORPHAN_SCAN_SCHEDULE_TIMEOUT. Add some
 * randomness to the timeout to minimize multple nodes firing the timer at the
 * same time.
 */
static inline unsigned long ocfs2_orphan_scan_timeout(void)
{
    unsigned long time;

    get_random_bytes(&time, sizeof(time));
    time = ORPHAN_SCAN_SCHEDULE_TIMEOUT + (time % 5000);
    return msecs_to_jiffies(time);
}

/*
 * ocfs2_queue_orphan_scan calls ocfs2_queue_recovery_completion for
 * every slot, queuing a recovery of the slot on the ocfs2_wq thread. This
 * is done to catch any orphans that are left over in orphan directories.
 *
 * It scans all slots, even ones that are in use. It does so to handle the
 * case described below:
 *
 *   Node 1 has an inode it was using. The dentry went away due to memory
 *   pressure.  Node 1 closes the inode, but it's on the free list. The node
 *   has the open lock.
 *   Node 2 unlinks the inode. It grabs the dentry lock to notify others,
 *   but node 1 has no dentry and doesn't get the message. It trylocks the
 *   open lock, sees that another node has a PR, and does nothing.
 *   Later node 2 runs its orphan dir. It igets the inode, trylocks the
 *   open lock, sees the PR still, and does nothing.
 *   Basically, we have to trigger an orphan iput on node 1. The only way
 *   for this to happen is if node 1 runs node 2's orphan dir.
 *
 * ocfs2_queue_orphan_scan gets called every ORPHAN_SCAN_SCHEDULE_TIMEOUT
 * seconds.  It gets an EX lock on os_lockres and checks sequence number
 * stored in LVB. If the sequence number has changed, it means some other
 * node has done the scan.  This node skips the scan and tracks the
 * sequence number.  If the sequence number didn't change, it means a scan
 * hasn't happened.  The node queues a scan and increments the
 * sequence number in the LVB.
 */
void ocfs2_queue_orphan_scan(struct ocfs2_super *osb)
{
    struct ocfs2_orphan_scan *os;
    int status, i;
    u32 seqno = 0;

    os = &osb->osb_orphan_scan;

    if (atomic_read(&os->os_state) == ORPHAN_SCAN_INACTIVE)
        goto out;

    trace_ocfs2_queue_orphan_scan_begin(os->os_count, os->os_seqno,
                        atomic_read(&os->os_state));

    status = ocfs2_orphan_scan_lock(osb, &seqno);
    if (status < 0) {
        if (status != -EAGAIN)
            mlog_errno(status);
        goto out;
    }

    /* Do no queue the tasks if the volume is being umounted */
    if (atomic_read(&os->os_state) == ORPHAN_SCAN_INACTIVE)
        goto unlock;

    if (os->os_seqno != seqno) {
        os->os_seqno = seqno;
        goto unlock;
    }

    for (i = 0; i < osb->max_slots; i++)
        ocfs2_queue_recovery_completion(osb->journal, i, NULL, NULL,
                        NULL);
    /*
     * We queued a recovery on orphan slots, increment the sequence
     * number and update LVB so other node will skip the scan for a while
     */
    seqno++;
    os->os_count++;
    os->os_scantime = CURRENT_TIME;
unlock:
    ocfs2_orphan_scan_unlock(osb, seqno);
out:
    trace_ocfs2_queue_orphan_scan_end(os->os_count, os->os_seqno,
                      atomic_read(&os->os_state));
    return;
}

/* Worker task that gets fired every ORPHAN_SCAN_SCHEDULE_TIMEOUT millsec */
void ocfs2_orphan_scan_work(struct work_struct *work)
{
    struct ocfs2_orphan_scan *os;
    struct ocfs2_super *osb;

    os = container_of(work, struct ocfs2_orphan_scan,
              os_orphan_scan_work.work);
    osb = os->os_osb;

    mutex_lock(&os->os_lock);
    ocfs2_queue_orphan_scan(osb);
    if (atomic_read(&os->os_state) == ORPHAN_SCAN_ACTIVE)
        queue_delayed_work(ocfs2_wq, &os->os_orphan_scan_work,
                      ocfs2_orphan_scan_timeout());
    mutex_unlock(&os->os_lock);
}

void ocfs2_orphan_scan_stop(struct ocfs2_super *osb)
{
    struct ocfs2_orphan_scan *os;

    os = &osb->osb_orphan_scan;
    if (atomic_read(&os->os_state) == ORPHAN_SCAN_ACTIVE) {
        atomic_set(&os->os_state, ORPHAN_SCAN_INACTIVE);
        mutex_lock(&os->os_lock);
        cancel_delayed_work(&os->os_orphan_scan_work);
        mutex_unlock(&os->os_lock);
    }
}

void ocfs2_orphan_scan_init(struct ocfs2_super *osb)
{
    struct ocfs2_orphan_scan *os;

    os = &osb->osb_orphan_scan;
    os->os_osb = osb;
    os->os_count = 0;
    os->os_seqno = 0;
    mutex_init(&os->os_lock);
    INIT_DELAYED_WORK(&os->os_orphan_scan_work, ocfs2_orphan_scan_work);
}

void ocfs2_orphan_scan_start(struct ocfs2_super *osb)
{
    struct ocfs2_orphan_scan *os;

    os = &osb->osb_orphan_scan;
    os->os_scantime = CURRENT_TIME;
    if (ocfs2_is_hard_readonly(osb) || ocfs2_mount_local(osb))
        atomic_set(&os->os_state, ORPHAN_SCAN_INACTIVE);
    else {
        atomic_set(&os->os_state, ORPHAN_SCAN_ACTIVE);
        queue_delayed_work(ocfs2_wq, &os->os_orphan_scan_work,
                   ocfs2_orphan_scan_timeout());
    }
}

struct ocfs2_orphan_filldir_priv {
    struct inode        *head;
    struct ocfs2_super  *osb;
};

static int ocfs2_orphan_filldir(void *priv, const char *name, int name_len,
                loff_t pos, u64 ino, unsigned type)
{
    struct ocfs2_orphan_filldir_priv *p = priv;
    struct inode *iter;

    if (name_len == 1 && !strncmp(".", name, 1))
        return 0;
    if (name_len == 2 && !strncmp("..", name, 2))
        return 0;

    /* Skip bad inodes so that recovery can continue */
    iter = ocfs2_iget(p->osb, ino,
              OCFS2_FI_FLAG_ORPHAN_RECOVERY, 0);
    if (IS_ERR(iter))
        return 0;

    trace_ocfs2_orphan_filldir((unsigned long long)OCFS2_I(iter)->ip_blkno);
    /* No locking is required for the next_orphan queue as there
     * is only ever a single process doing orphan recovery. */
    OCFS2_I(iter)->ip_next_orphan = p->head;
    p->head = iter;

    return 0;
}

static int ocfs2_queue_orphans(struct ocfs2_super *osb,
                   int slot,
                   struct inode **head)
{
    int status;
    struct inode *orphan_dir_inode = NULL;
    struct ocfs2_orphan_filldir_priv priv;
    loff_t pos = 0;

    priv.osb = osb;
    priv.head = *head;

    orphan_dir_inode = ocfs2_get_system_file_inode(osb,
                               ORPHAN_DIR_SYSTEM_INODE,
                               slot);
    if  (!orphan_dir_inode) {
        status = -ENOENT;
        mlog_errno(status);
        return status;
    }

    mutex_lock(&orphan_dir_inode->i_mutex);
    status = ocfs2_inode_lock(orphan_dir_inode, NULL, 0);
    if (status < 0) {
        mlog_errno(status);
        goto out;
    }

    status = ocfs2_dir_foreach(orphan_dir_inode, &pos, &priv,
                   ocfs2_orphan_filldir);
    if (status) {
        mlog_errno(status);
        goto out_cluster;
    }

    *head = priv.head;

out_cluster:
    ocfs2_inode_unlock(orphan_dir_inode, 0);
out:
    mutex_unlock(&orphan_dir_inode->i_mutex);
    iput(orphan_dir_inode);
    return status;
}

static int ocfs2_orphan_recovery_can_continue(struct ocfs2_super *osb,
                          int slot)
{
    int ret;

    spin_lock(&osb->osb_lock);
    ret = !osb->osb_orphan_wipes[slot];
    spin_unlock(&osb->osb_lock);
    return ret;
}

static void ocfs2_mark_recovering_orphan_dir(struct ocfs2_super *osb,
                         int slot)
{
    spin_lock(&osb->osb_lock);
    /* Mark ourselves such that new processes in delete_inode()
     * know to quit early. */
    ocfs2_node_map_set_bit(osb, &osb->osb_recovering_orphan_dirs, slot);
    while (osb->osb_orphan_wipes[slot]) {
        /* If any processes are already in the middle of an
         * orphan wipe on this dir, then we need to wait for
         * them. */
        spin_unlock(&osb->osb_lock);
        wait_event_interruptible(osb->osb_wipe_event,
                     ocfs2_orphan_recovery_can_continue(osb, slot));
        spin_lock(&osb->osb_lock);
    }
    spin_unlock(&osb->osb_lock);
}

static void ocfs2_clear_recovering_orphan_dir(struct ocfs2_super *osb,
                          int slot)
{
    ocfs2_node_map_clear_bit(osb, &osb->osb_recovering_orphan_dirs, slot);
}

/*
 * Orphan recovery. Each mounted node has it's own orphan dir which we
 * must run during recovery. Our strategy here is to build a list of
 * the inodes in the orphan dir and iget/iput them. The VFS does
 * (most) of the rest of the work.
 *
 * Orphan recovery can happen at any time, not just mount so we have a
 * couple of extra considerations.
 *
 * - We grab as many inodes as we can under the orphan dir lock -
 *   doing iget() outside the orphan dir risks getting a reference on
 *   an invalid inode.
 * - We must be sure not to deadlock with other processes on the
 *   system wanting to run delete_inode(). This can happen when they go
 *   to lock the orphan dir and the orphan recovery process attempts to
 *   iget() inside the orphan dir lock. This can be avoided by
 *   advertising our state to ocfs2_delete_inode().
 */
static int ocfs2_recover_orphans(struct ocfs2_super *osb,
                 int slot)
{
    int ret = 0;
    struct inode *inode = NULL;
    struct inode *iter;
    struct ocfs2_inode_info *oi;

    trace_ocfs2_recover_orphans(slot);

    ocfs2_mark_recovering_orphan_dir(osb, slot);
    ret = ocfs2_queue_orphans(osb, slot, &inode);
    ocfs2_clear_recovering_orphan_dir(osb, slot);

    /* Error here should be noted, but we want to continue with as
     * many queued inodes as we've got. */
    if (ret)
        mlog_errno(ret);

    while (inode) {
        oi = OCFS2_I(inode);
        trace_ocfs2_recover_orphans_iput(
                    (unsigned long long)oi->ip_blkno);

        iter = oi->ip_next_orphan;

        spin_lock(&oi->ip_lock);
        /* The remote delete code may have set these on the
         * assumption that the other node would wipe them
         * successfully.  If they are still in the node's
         * orphan dir, we need to reset that state. */
        oi->ip_flags &= ~(OCFS2_INODE_DELETED|OCFS2_INODE_SKIP_DELETE);

        /* Set the proper information to get us going into
         * ocfs2_delete_inode. */
        oi->ip_flags |= OCFS2_INODE_MAYBE_ORPHANED;
        spin_unlock(&oi->ip_lock);

        iput(inode);

        inode = iter;
    }

    return ret;
}

static int __ocfs2_wait_on_mount(struct ocfs2_super *osb, int quota)
{
    /* This check is good because ocfs2 will wait on our recovery
     * thread before changing it to something other than MOUNTED
     * or DISABLED. */
    wait_event(osb->osb_mount_event,
          (!quota && atomic_read(&osb->vol_state) == VOLUME_MOUNTED) ||
           atomic_read(&osb->vol_state) == VOLUME_MOUNTED_QUOTAS ||
           atomic_read(&osb->vol_state) == VOLUME_DISABLED);

    /* If there's an error on mount, then we may never get to the
     * MOUNTED flag, but this is set right before
     * dismount_volume() so we can trust it. */
    if (atomic_read(&osb->vol_state) == VOLUME_DISABLED) {
        trace_ocfs2_wait_on_mount(VOLUME_DISABLED);
        mlog(0, "mount error, exiting!\n");
        return -EBUSY;
    }

    return 0;
}

static int ocfs2_commit_thread(void *arg)
{
    int status;
    struct ocfs2_super *osb = arg;
    struct ocfs2_journal *journal = osb->journal;

    /* we can trust j_num_trans here because _should_stop() is only set in
     * shutdown and nobody other than ourselves should be able to start
     * transactions.  committing on shutdown might take a few iterations
     * as final transactions put deleted inodes on the list */
    while (!(kthread_should_stop() &&
         atomic_read(&journal->j_num_trans) == 0)) {

        wait_event_interruptible(osb->checkpoint_event,
                     atomic_read(&journal->j_num_trans)
                     || kthread_should_stop());

        status = ocfs2_commit_cache(osb);
        if (status < 0)
            mlog_errno(status);

        if (kthread_should_stop() && atomic_read(&journal->j_num_trans)){
            mlog(ML_KTHREAD,
                 "commit_thread: %u transactions pending on "
                 "shutdown\n",
                 atomic_read(&journal->j_num_trans));
        }
    }

    return 0;
}

/* Reads all the journal inodes without taking any cluster locks. Used
 * for hard readonly access to determine whether any journal requires
 * recovery. Also used to refresh the recovery generation numbers after
 * a journal has been recovered by another node.
 */
int ocfs2_check_journals_nolocks(struct ocfs2_super *osb)
{
    int ret = 0;
    unsigned int slot;
    struct buffer_head *di_bh = NULL;
    struct ocfs2_dinode *di;
    int journal_dirty = 0;

    for(slot = 0; slot < osb->max_slots; slot++) {
        ret = ocfs2_read_journal_inode(osb, slot, &di_bh, NULL);
        if (ret) {
            mlog_errno(ret);
            goto out;
        }

        di = (struct ocfs2_dinode *) di_bh->b_data;

        osb->slot_recovery_generations[slot] =
                    ocfs2_get_recovery_generation(di);

        if (le32_to_cpu(di->id1.journal1.ij_flags) &
            OCFS2_JOURNAL_DIRTY_FL)
            journal_dirty = 1;

        brelse(di_bh);
        di_bh = NULL;
    }

out:
    if (journal_dirty)
        ret = -EROFS;
    return ret;
}