/* -*- 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);

  	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);

  		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);

  	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
  ",
  	     (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
  ");
  }
  
  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!
  ");
  		mlog(ML_ERROR, "b_blocknr=%llu
  ",
  		     (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!
  ");

  	}

  	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!
  ",
  		     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)
  ");
  		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!
  ");
  		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!
  ",
  		     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
  ");
  		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.
  ", olderr, slot);
  		mlog(ML_ERROR, "File system on device %s needs checking.
  ",
  		     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!
  ");
  		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)!
  ",
  			     status, node_num,
  			     MAJOR(osb->sb->s_dev), MINOR(osb->sb->s_dev));
  			mlog(ML_ERROR, "Volume requires unmount.
  ");

  		}

  		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!
  ");
  		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)
  ", 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
  ");
  		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)
  ", 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
  ");
  		status = -EACCES;
  		goto bail;
  	}
  	if (is_bad_inode(inode)) {
  		mlog(ML_ERROR, "access error (bad inode)
  ");
  		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!
  ");
  		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
  ",
  			     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;
  }