fs/ocfs2/journal.h - arm/linux - Git at Google

 /* -*- mode: c; c-basic-offset: 8; -*-
  * vim: noexpandtab sw=8 ts=8 sts=0:
  *
  * journal.h
  *
  * Defines journalling api and structures.
  *
  * Copyright (C) 2003, 2005 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.
  */

 #ifndef OCFS2_JOURNAL_H
 #define OCFS2_JOURNAL_H

 #include <linux/fs.h>
 #include <linux/jbd.h>

 enum ocfs2_journal_state {
 	OCFS2_JOURNAL_FREE = 0,
 	OCFS2_JOURNAL_LOADED,
 	OCFS2_JOURNAL_IN_SHUTDOWN,
 };

 struct ocfs2_super;
 struct ocfs2_dinode;

 struct ocfs2_journal {
 	enum ocfs2_journal_state   j_state;    /* Journals current state   */

 	journal_t                 *j_journal; /* The kernels journal type */
 	struct inode              *j_inode;   /* Kernel inode pointing to
 					       * this journal             */
 	struct ocfs2_super        *j_osb;     /* pointer to the super
 					       * block for the node
 					       * we're currently
 					       * running on -- not
 					       * necessarily the super
 					       * block from the node
 					       * which we usually run
 					       * from (recovery,
 					       * etc)                     */
 	struct buffer_head        *j_bh;      /* Journal disk inode block */
 	atomic_t                  j_num_trans; /* Number of transactions
 					        * currently in the system. */
 	unsigned long             j_trans_id;
 	struct rw_semaphore       j_trans_barrier;
 	wait_queue_head_t         j_checkpointed;

 	spinlock_t                j_lock;
 	struct list_head          j_la_cleanups;
 	struct work_struct        j_recovery_work;
 };

 extern spinlock_t trans_inc_lock;

 /* wrap j_trans_id so we never have it equal to zero. */
 static inline unsigned long ocfs2_inc_trans_id(struct ocfs2_journal *j)
 {
 	unsigned long old_id;
 	spin_lock(&trans_inc_lock);
 	old_id = j->j_trans_id++;
 	if (unlikely(!j->j_trans_id))
 		j->j_trans_id = 1;
 	spin_unlock(&trans_inc_lock);
 	return old_id;
 }

 static inline void ocfs2_set_inode_lock_trans(struct ocfs2_journal *journal,
 					      struct inode *inode)
 {
 	spin_lock(&trans_inc_lock);
 	OCFS2_I(inode)->ip_last_trans = journal->j_trans_id;
 	spin_unlock(&trans_inc_lock);
 }

 /* Used to figure out whether it's safe to drop a metadata lock on an
  * inode. Returns true if all the inodes changes have been
  * checkpointed to disk. You should be holding the spinlock on the
  * metadata lock while calling this to be sure that nobody can take
  * the lock and put it on another transaction. */
 static inline int ocfs2_inode_fully_checkpointed(struct inode *inode)
 {
 	int ret;
 	struct ocfs2_journal *journal = OCFS2_SB(inode->i_sb)->journal;

 	spin_lock(&trans_inc_lock);
 	ret = time_after(journal->j_trans_id, OCFS2_I(inode)->ip_last_trans);
 	spin_unlock(&trans_inc_lock);
 	return ret;
 }

 /* convenience function to check if an inode is still new (has never
  * hit disk) Will do you a favor and set created_trans = 0 when you've
  * been checkpointed.  returns '1' if the inode is still new. */
 static inline int ocfs2_inode_is_new(struct inode *inode)
 {
 	int ret;

 	/* System files are never "new" as they're written out by
 	 * mkfs. This helps us early during mount, before we have the
 	 * journal open and j_trans_id could be junk. */
 	if (OCFS2_I(inode)->ip_flags & OCFS2_INODE_SYSTEM_FILE)
 		return 0;
 	spin_lock(&trans_inc_lock);
 	ret = !(time_after(OCFS2_SB(inode->i_sb)->journal->j_trans_id,
 			   OCFS2_I(inode)->ip_created_trans));
 	if (!ret)
 		OCFS2_I(inode)->ip_created_trans = 0;
 	spin_unlock(&trans_inc_lock);
 	return ret;
 }

 static inline void ocfs2_inode_set_new(struct ocfs2_super *osb,
 				       struct inode *inode)
 {
 	spin_lock(&trans_inc_lock);
 	OCFS2_I(inode)->ip_created_trans = osb->journal->j_trans_id;
 	spin_unlock(&trans_inc_lock);
 }

 /* Exported only for the journal struct init code in super.c. Do not call. */
 void ocfs2_complete_recovery(struct work_struct *work);
 void ocfs2_wait_for_recovery(struct ocfs2_super *osb);

 int ocfs2_recovery_init(struct ocfs2_super *osb);
 void ocfs2_recovery_exit(struct ocfs2_super *osb);

 /*
  *  Journal Control:
  *  Initialize, Load, Shutdown, Wipe a journal.
  *
  *  ocfs2_journal_init     - Initialize journal structures in the OSB.
  *  ocfs2_journal_load     - Load the given journal off disk. Replay it if
  *                          there's transactions still in there.
  *  ocfs2_journal_shutdown - Shutdown a journal, this will flush all
  *                          uncommitted, uncheckpointed transactions.
  *  ocfs2_journal_wipe     - Wipe transactions from a journal. Optionally
  *                          zero out each block.
  *  ocfs2_recovery_thread  - Perform recovery on a node. osb is our own osb.
  *  ocfs2_mark_dead_nodes - Start recovery on nodes we won't get a heartbeat
  *                          event on.
  *  ocfs2_start_checkpoint - Kick the commit thread to do a checkpoint.
  */
 void   ocfs2_set_journal_params(struct ocfs2_super *osb);
 int    ocfs2_journal_init(struct ocfs2_journal *journal,
 			  int *dirty);
 void   ocfs2_journal_shutdown(struct ocfs2_super *osb);
 int    ocfs2_journal_wipe(struct ocfs2_journal *journal,
 			  int full);
 int    ocfs2_journal_load(struct ocfs2_journal *journal, int local,
 			  int replayed);
 int    ocfs2_check_journals_nolocks(struct ocfs2_super *osb);
 void   ocfs2_recovery_thread(struct ocfs2_super *osb,
 			     int node_num);
 int    ocfs2_mark_dead_nodes(struct ocfs2_super *osb);
 void   ocfs2_complete_mount_recovery(struct ocfs2_super *osb);

 static inline void ocfs2_start_checkpoint(struct ocfs2_super *osb)
 {
 	atomic_set(&osb->needs_checkpoint, 1);
 	wake_up(&osb->checkpoint_event);
 }

 static inline void ocfs2_checkpoint_inode(struct inode *inode)
 {
 	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);

 	if (ocfs2_mount_local(osb))
 		return;

 	if (!ocfs2_inode_fully_checkpointed(inode)) {
 		/* WARNING: This only kicks off a single
 		 * checkpoint. If someone races you and adds more
 		 * metadata to the journal, you won't know, and will
 		 * wind up waiting *alot* longer than necessary. Right
 		 * now we only use this in clear_inode so that's
 		 * OK. */
 		ocfs2_start_checkpoint(osb);

 		wait_event(osb->journal->j_checkpointed,
 			   ocfs2_inode_fully_checkpointed(inode));
 	}
 }

 /*
  *  Transaction Handling:
  *  Manage the lifetime of a transaction handle.
  *
  *  ocfs2_start_trans      - Begin a transaction. Give it an upper estimate of
  *                          the number of blocks that will be changed during
  *                          this handle.
  *  ocfs2_commit_trans - Complete a handle. It might return -EIO if
  *                       the journal was aborted. The majority of paths don't
  *                       check the return value as an error there comes too
  *                       late to do anything (and will be picked up in a
  *                       later transaction).
  *  ocfs2_extend_trans     - Extend a handle by nblocks credits. This may
  *                          commit the handle to disk in the process, but will
  *                          not release any locks taken during the transaction.
  *  ocfs2_journal_access   - Notify the handle that we want to journal this
  *                          buffer. Will have to call ocfs2_journal_dirty once
  *                          we've actually dirtied it. Type is one of . or .
  *  ocfs2_journal_dirty    - Mark a journalled buffer as having dirty data.
  *  ocfs2_journal_dirty_data - Indicate that a data buffer should go out before
  *                             the current handle commits.
  */

 /* You must always start_trans with a number of buffs > 0, but it's
  * perfectly legal to go through an entire transaction without having
  * dirtied any buffers. */
 handle_t		    *ocfs2_start_trans(struct ocfs2_super *osb,
 					       int max_buffs);
 int			     ocfs2_commit_trans(struct ocfs2_super *osb,
 						handle_t *handle);
 int			     ocfs2_extend_trans(handle_t *handle, int nblocks);

 /*
  * Create access is for when we get a newly created buffer and we're
  * not gonna read it off disk, but rather fill it ourselves.  Right
  * now, we don't do anything special with this (it turns into a write
  * request), but this is a good placeholder in case we do...
  *
  * Write access is for when we read a block off disk and are going to
  * modify it. This way the journalling layer knows it may need to make
  * a copy of that block (if it's part of another, uncommitted
  * transaction) before we do so.
  */
 #define OCFS2_JOURNAL_ACCESS_CREATE 0
 #define OCFS2_JOURNAL_ACCESS_WRITE  1
 #define OCFS2_JOURNAL_ACCESS_UNDO   2

 int                  ocfs2_journal_access(handle_t *handle,
 					  struct inode *inode,
 					  struct buffer_head *bh,
 					  int type);
 /*
  * A word about the journal_access/journal_dirty "dance". It is
  * entirely legal to journal_access a buffer more than once (as long
  * as the access type is the same -- I'm not sure what will happen if
  * access type is different but this should never happen anyway) It is
  * also legal to journal_dirty a buffer more than once. In fact, you
  * can even journal_access a buffer after you've done a
  * journal_access/journal_dirty pair. The only thing you cannot do
  * however, is journal_dirty a buffer which you haven't yet passed to
  * journal_access at least once.
  *
  * That said, 99% of the time this doesn't matter and this is what the
  * path looks like:
  *
  *	<read a bh>
  *	ocfs2_journal_access(handle, bh,	OCFS2_JOURNAL_ACCESS_WRITE);
  *	<modify the bh>
  * 	ocfs2_journal_dirty(handle, bh);
  */
 int                  ocfs2_journal_dirty(handle_t *handle,
 					 struct buffer_head *bh);
 int                  ocfs2_journal_dirty_data(handle_t *handle,
 					      struct buffer_head *bh);

 /*
  *  Credit Macros:
  *  Convenience macros to calculate number of credits needed.
  *
  *  For convenience sake, I have a set of macros here which calculate
  *  the *maximum* number of sectors which will be changed for various
  *  metadata updates.
  */

 /* simple file updates like chmod, etc. */
 #define OCFS2_INODE_UPDATE_CREDITS 1

 /* group extend. inode update and last group update. */
 #define OCFS2_GROUP_EXTEND_CREDITS	(OCFS2_INODE_UPDATE_CREDITS + 1)

 /* group add. inode update and the new group update. */
 #define OCFS2_GROUP_ADD_CREDITS	(OCFS2_INODE_UPDATE_CREDITS + 1)

 /* get one bit out of a suballocator: dinode + group descriptor +
  * prev. group desc. if we relink. */
 #define OCFS2_SUBALLOC_ALLOC (3)

 #define OCFS2_INLINE_TO_EXTENTS_CREDITS (OCFS2_SUBALLOC_ALLOC		\
 					 + OCFS2_INODE_UPDATE_CREDITS)

 /* dinode + group descriptor update. We don't relink on free yet. */
 #define OCFS2_SUBALLOC_FREE  (2)

 #define OCFS2_TRUNCATE_LOG_UPDATE OCFS2_INODE_UPDATE_CREDITS
 #define OCFS2_TRUNCATE_LOG_FLUSH_ONE_REC (OCFS2_SUBALLOC_FREE 		      \
 					 + OCFS2_TRUNCATE_LOG_UPDATE)

 #define OCFS2_REMOVE_EXTENT_CREDITS (OCFS2_TRUNCATE_LOG_UPDATE + OCFS2_INODE_UPDATE_CREDITS)

 /* data block for new dir/symlink, 2 for bitmap updates (bitmap fe +
  * bitmap block for the new bit) */
 #define OCFS2_DIR_LINK_ADDITIONAL_CREDITS (1 + 2)

 /* parent fe, parent block, new file entry, inode alloc fe, inode alloc
  * group descriptor + mkdir/symlink blocks */
 #define OCFS2_MKNOD_CREDITS (3 + OCFS2_SUBALLOC_ALLOC                         \
 			    + OCFS2_DIR_LINK_ADDITIONAL_CREDITS)

 /* local alloc metadata change + main bitmap updates */
 #define OCFS2_WINDOW_MOVE_CREDITS (OCFS2_INODE_UPDATE_CREDITS                 \
 				  + OCFS2_SUBALLOC_ALLOC + OCFS2_SUBALLOC_FREE)

 /* used when we don't need an allocation change for a dir extend. One
  * for the dinode, one for the new block. */
 #define OCFS2_SIMPLE_DIR_EXTEND_CREDITS (2)

 /* file update (nlink, etc) + directory mtime/ctime + dir entry block */
 #define OCFS2_LINK_CREDITS  (2*OCFS2_INODE_UPDATE_CREDITS + 1)

 /* inode + dir inode (if we unlink a dir), + dir entry block + orphan
  * dir inode link */
 #define OCFS2_UNLINK_CREDITS  (2 * OCFS2_INODE_UPDATE_CREDITS + 1             \
 			      + OCFS2_LINK_CREDITS)

 /* dinode + orphan dir dinode + inode alloc dinode + orphan dir entry +
  * inode alloc group descriptor */
 #define OCFS2_DELETE_INODE_CREDITS (3 * OCFS2_INODE_UPDATE_CREDITS + 1 + 1)

 /* dinode update, old dir dinode update, new dir dinode update, old
  * dir dir entry, new dir dir entry, dir entry update for renaming
  * directory + target unlink */
 #define OCFS2_RENAME_CREDITS (3 * OCFS2_INODE_UPDATE_CREDITS + 3              \
 			     + OCFS2_UNLINK_CREDITS)

 static inline int ocfs2_calc_extend_credits(struct super_block *sb,
 					    struct ocfs2_dinode *fe,
 					    u32 bits_wanted)
 {
 	int bitmap_blocks, sysfile_bitmap_blocks, dinode_blocks;

 	/* bitmap dinode, group desc. + relinked group. */
 	bitmap_blocks = OCFS2_SUBALLOC_ALLOC;

 	/* we might need to shift tree depth so lets assume an
 	 * absolute worst case of complete fragmentation.  Even with
 	 * that, we only need one update for the dinode, and then
 	 * however many metadata chunks needed * a remaining suballoc
 	 * alloc. */
 	sysfile_bitmap_blocks = 1 +
 		(OCFS2_SUBALLOC_ALLOC - 1) * ocfs2_extend_meta_needed(fe);

 	/* this does not include *new* metadata blocks, which are
 	 * accounted for in sysfile_bitmap_blocks. fe +
 	 * prev. last_eb_blk + blocks along edge of tree.
 	 * calc_symlink_credits passes because we just need 1
 	 * credit for the dinode there. */
 	dinode_blocks = 1 + 1 + le16_to_cpu(fe->id2.i_list.l_tree_depth);

 	return bitmap_blocks + sysfile_bitmap_blocks + dinode_blocks;
 }

 static inline int ocfs2_calc_symlink_credits(struct super_block *sb)
 {
 	int blocks = OCFS2_MKNOD_CREDITS;

 	/* links can be longer than one block so we may update many
 	 * within our single allocated extent. */
 	blocks += ocfs2_clusters_to_blocks(sb, 1);

 	return blocks;
 }

 static inline int ocfs2_calc_group_alloc_credits(struct super_block *sb,
 						 unsigned int cpg)
 {
 	int blocks;
 	int bitmap_blocks = OCFS2_SUBALLOC_ALLOC + 1;
 	/* parent inode update + new block group header + bitmap inode update
 	   + bitmap blocks affected */
 	blocks = 1 + 1 + 1 + bitmap_blocks;
 	return blocks;
 }

 static inline int ocfs2_calc_tree_trunc_credits(struct super_block *sb,
 						unsigned int clusters_to_del,
 						struct ocfs2_dinode *fe,
 						struct ocfs2_extent_list *last_el)
 {
  	/* for dinode + all headers in this pass + update to next leaf */
 	u16 next_free = le16_to_cpu(last_el->l_next_free_rec);
 	u16 tree_depth = le16_to_cpu(fe->id2.i_list.l_tree_depth);
 	int credits = 1 + tree_depth + 1;
 	int i;

 	i = next_free - 1;
 	BUG_ON(i < 0);

 	/* We may be deleting metadata blocks, so metadata alloc dinode +
 	   one desc. block for each possible delete. */
 	if (tree_depth && next_free == 1 &&
 	    ocfs2_rec_clusters(last_el, &last_el->l_recs[i]) == clusters_to_del)
 		credits += 1 + tree_depth;

 	/* update to the truncate log. */
 	credits += OCFS2_TRUNCATE_LOG_UPDATE;

 	return credits;
 }

 #endif /* OCFS2_JOURNAL_H */
	/* -- mode: c; c-basic-offset: 8; --
	* vim: noexpandtab sw=8 ts=8 sts=0:
	*
	* journal.h
	*
	* Defines journalling api and structures.
	*
	* Copyright (C) 2003, 2005 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.
	*/

	#ifndef OCFS2_JOURNAL_H
	#define OCFS2_JOURNAL_H

	#include <linux/fs.h>
	#include <linux/jbd.h>

	enum ocfs2_journal_state {
	OCFS2_JOURNAL_FREE = 0,
	OCFS2_JOURNAL_LOADED,
	OCFS2_JOURNAL_IN_SHUTDOWN,
	};

	struct ocfs2_super;
	struct ocfs2_dinode;

	struct ocfs2_journal {
	enum ocfs2_journal_state j_state; /* Journals current state */

	journal_t j_journal; / The kernels journal type */
	struct inode j_inode; / Kernel inode pointing to
	* this journal */
	struct ocfs2_super j_osb; / pointer to the super
	* block for the node
	* we're currently
	* running on -- not
	* necessarily the super
	* block from the node
	* which we usually run
	* from (recovery,
	* etc) */
	struct buffer_head j_bh; / Journal disk inode block */
	atomic_t j_num_trans; /* Number of transactions
	* currently in the system. */
	unsigned long j_trans_id;
	struct rw_semaphore j_trans_barrier;
	wait_queue_head_t j_checkpointed;

	spinlock_t j_lock;
	struct list_head j_la_cleanups;
	struct work_struct j_recovery_work;
	};

	extern spinlock_t trans_inc_lock;

	/* wrap j_trans_id so we never have it equal to zero. */
	static inline unsigned long ocfs2_inc_trans_id(struct ocfs2_journal *j)
	{
	unsigned long old_id;
	spin_lock(&trans_inc_lock);
	old_id = j->j_trans_id++;
	if (unlikely(!j->j_trans_id))
	j->j_trans_id = 1;
	spin_unlock(&trans_inc_lock);
	return old_id;
	}

	static inline void ocfs2_set_inode_lock_trans(struct ocfs2_journal *journal,
	struct inode *inode)
	{
	spin_lock(&trans_inc_lock);
	OCFS2_I(inode)->ip_last_trans = journal->j_trans_id;
	spin_unlock(&trans_inc_lock);
	}

	/* Used to figure out whether it's safe to drop a metadata lock on an
	* inode. Returns true if all the inodes changes have been
	* checkpointed to disk. You should be holding the spinlock on the
	* metadata lock while calling this to be sure that nobody can take
	* the lock and put it on another transaction. */
	static inline int ocfs2_inode_fully_checkpointed(struct inode *inode)
	{
	int ret;
	struct ocfs2_journal *journal = OCFS2_SB(inode->i_sb)->journal;

	spin_lock(&trans_inc_lock);
	ret = time_after(journal->j_trans_id, OCFS2_I(inode)->ip_last_trans);
	spin_unlock(&trans_inc_lock);
	return ret;
	}

	/* convenience function to check if an inode is still new (has never
	* hit disk) Will do you a favor and set created_trans = 0 when you've
	* been checkpointed. returns '1' if the inode is still new. */
	static inline int ocfs2_inode_is_new(struct inode *inode)
	{
	int ret;

	/* System files are never "new" as they're written out by
	* mkfs. This helps us early during mount, before we have the
	* journal open and j_trans_id could be junk. */
	if (OCFS2_I(inode)->ip_flags & OCFS2_INODE_SYSTEM_FILE)
	return 0;
	spin_lock(&trans_inc_lock);
	ret = !(time_after(OCFS2_SB(inode->i_sb)->journal->j_trans_id,
	OCFS2_I(inode)->ip_created_trans));
	if (!ret)
	OCFS2_I(inode)->ip_created_trans = 0;
	spin_unlock(&trans_inc_lock);
	return ret;
	}

	static inline void ocfs2_inode_set_new(struct ocfs2_super *osb,
	struct inode *inode)
	{
	spin_lock(&trans_inc_lock);
	OCFS2_I(inode)->ip_created_trans = osb->journal->j_trans_id;
	spin_unlock(&trans_inc_lock);
	}

	/* Exported only for the journal struct init code in super.c. Do not call. */
	void ocfs2_complete_recovery(struct work_struct *work);
	void ocfs2_wait_for_recovery(struct ocfs2_super *osb);

	int ocfs2_recovery_init(struct ocfs2_super *osb);
	void ocfs2_recovery_exit(struct ocfs2_super *osb);

	/*
	* Journal Control:
	* Initialize, Load, Shutdown, Wipe a journal.
	*
	* ocfs2_journal_init - Initialize journal structures in the OSB.
	* ocfs2_journal_load - Load the given journal off disk. Replay it if
	* there's transactions still in there.
	* ocfs2_journal_shutdown - Shutdown a journal, this will flush all
	* uncommitted, uncheckpointed transactions.
	* ocfs2_journal_wipe - Wipe transactions from a journal. Optionally
	* zero out each block.
	* ocfs2_recovery_thread - Perform recovery on a node. osb is our own osb.
	* ocfs2_mark_dead_nodes - Start recovery on nodes we won't get a heartbeat
	* event on.
	* ocfs2_start_checkpoint - Kick the commit thread to do a checkpoint.
	*/
	void ocfs2_set_journal_params(struct ocfs2_super *osb);
	int ocfs2_journal_init(struct ocfs2_journal *journal,
	int *dirty);
	void ocfs2_journal_shutdown(struct ocfs2_super *osb);
	int ocfs2_journal_wipe(struct ocfs2_journal *journal,
	int full);
	int ocfs2_journal_load(struct ocfs2_journal *journal, int local,
	int replayed);
	int ocfs2_check_journals_nolocks(struct ocfs2_super *osb);
	void ocfs2_recovery_thread(struct ocfs2_super *osb,
	int node_num);
	int ocfs2_mark_dead_nodes(struct ocfs2_super *osb);
	void ocfs2_complete_mount_recovery(struct ocfs2_super *osb);

	static inline void ocfs2_start_checkpoint(struct ocfs2_super *osb)
	{
	atomic_set(&osb->needs_checkpoint, 1);
	wake_up(&osb->checkpoint_event);
	}

	static inline void ocfs2_checkpoint_inode(struct inode *inode)
	{
	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);

	if (ocfs2_mount_local(osb))
	return;

	if (!ocfs2_inode_fully_checkpointed(inode)) {
	/* WARNING: This only kicks off a single
	* checkpoint. If someone races you and adds more
	* metadata to the journal, you won't know, and will
	* wind up waiting alot longer than necessary. Right
	* now we only use this in clear_inode so that's
	* OK. */
	ocfs2_start_checkpoint(osb);

	wait_event(osb->journal->j_checkpointed,
	ocfs2_inode_fully_checkpointed(inode));
	}
	}

	/*
	* Transaction Handling:
	* Manage the lifetime of a transaction handle.
	*
	* ocfs2_start_trans - Begin a transaction. Give it an upper estimate of
	* the number of blocks that will be changed during
	* this handle.
	* ocfs2_commit_trans - Complete a handle. It might return -EIO if
	* the journal was aborted. The majority of paths don't
	* check the return value as an error there comes too
	* late to do anything (and will be picked up in a
	* later transaction).
	* ocfs2_extend_trans - Extend a handle by nblocks credits. This may
	* commit the handle to disk in the process, but will
	* not release any locks taken during the transaction.
	* ocfs2_journal_access - Notify the handle that we want to journal this
	* buffer. Will have to call ocfs2_journal_dirty once
	* we've actually dirtied it. Type is one of . or .
	* ocfs2_journal_dirty - Mark a journalled buffer as having dirty data.
	* ocfs2_journal_dirty_data - Indicate that a data buffer should go out before
	* the current handle commits.
	*/

	/* You must always start_trans with a number of buffs > 0, but it's
	* perfectly legal to go through an entire transaction without having
	* dirtied any buffers. */
	handle_t ocfs2_start_trans(struct ocfs2_super osb,
	int max_buffs);
	int ocfs2_commit_trans(struct ocfs2_super *osb,
	handle_t *handle);
	int ocfs2_extend_trans(handle_t *handle, int nblocks);

	/*
	* Create access is for when we get a newly created buffer and we're
	* not gonna read it off disk, but rather fill it ourselves. Right
	* now, we don't do anything special with this (it turns into a write
	* request), but this is a good placeholder in case we do...
	*
	* Write access is for when we read a block off disk and are going to
	* modify it. This way the journalling layer knows it may need to make
	* a copy of that block (if it's part of another, uncommitted
	* transaction) before we do so.
	*/
	#define OCFS2_JOURNAL_ACCESS_CREATE 0
	#define OCFS2_JOURNAL_ACCESS_WRITE 1
	#define OCFS2_JOURNAL_ACCESS_UNDO 2

	int ocfs2_journal_access(handle_t *handle,
	struct inode *inode,
	struct buffer_head *bh,
	int type);
	/*
	* A word about the journal_access/journal_dirty "dance". It is
	* entirely legal to journal_access a buffer more than once (as long
	* as the access type is the same -- I'm not sure what will happen if
	* access type is different but this should never happen anyway) It is
	* also legal to journal_dirty a buffer more than once. In fact, you
	* can even journal_access a buffer after you've done a
	* journal_access/journal_dirty pair. The only thing you cannot do
	* however, is journal_dirty a buffer which you haven't yet passed to
	* journal_access at least once.
	*
	* That said, 99% of the time this doesn't matter and this is what the
	* path looks like:
	*
	* <read a bh>
	* ocfs2_journal_access(handle, bh, OCFS2_JOURNAL_ACCESS_WRITE);
	* <modify the bh>
	* ocfs2_journal_dirty(handle, bh);
	*/
	int ocfs2_journal_dirty(handle_t *handle,
	struct buffer_head *bh);
	int ocfs2_journal_dirty_data(handle_t *handle,
	struct buffer_head *bh);

	/*
	* Credit Macros:
	* Convenience macros to calculate number of credits needed.
	*
	* For convenience sake, I have a set of macros here which calculate
	* the maximum number of sectors which will be changed for various
	* metadata updates.
	*/

	/* simple file updates like chmod, etc. */
	#define OCFS2_INODE_UPDATE_CREDITS 1

	/* group extend. inode update and last group update. */
	#define OCFS2_GROUP_EXTEND_CREDITS (OCFS2_INODE_UPDATE_CREDITS + 1)

	/* group add. inode update and the new group update. */
	#define OCFS2_GROUP_ADD_CREDITS (OCFS2_INODE_UPDATE_CREDITS + 1)

	/* get one bit out of a suballocator: dinode + group descriptor +
	* prev. group desc. if we relink. */
	#define OCFS2_SUBALLOC_ALLOC (3)

	#define OCFS2_INLINE_TO_EXTENTS_CREDITS (OCFS2_SUBALLOC_ALLOC \
	+ OCFS2_INODE_UPDATE_CREDITS)

	/* dinode + group descriptor update. We don't relink on free yet. */
	#define OCFS2_SUBALLOC_FREE (2)

	#define OCFS2_TRUNCATE_LOG_UPDATE OCFS2_INODE_UPDATE_CREDITS
	#define OCFS2_TRUNCATE_LOG_FLUSH_ONE_REC (OCFS2_SUBALLOC_FREE \
	+ OCFS2_TRUNCATE_LOG_UPDATE)

	#define OCFS2_REMOVE_EXTENT_CREDITS (OCFS2_TRUNCATE_LOG_UPDATE + OCFS2_INODE_UPDATE_CREDITS)

	/* data block for new dir/symlink, 2 for bitmap updates (bitmap fe +
	* bitmap block for the new bit) */
	#define OCFS2_DIR_LINK_ADDITIONAL_CREDITS (1 + 2)

	/* parent fe, parent block, new file entry, inode alloc fe, inode alloc
	* group descriptor + mkdir/symlink blocks */
	#define OCFS2_MKNOD_CREDITS (3 + OCFS2_SUBALLOC_ALLOC \
	+ OCFS2_DIR_LINK_ADDITIONAL_CREDITS)

	/* local alloc metadata change + main bitmap updates */
	#define OCFS2_WINDOW_MOVE_CREDITS (OCFS2_INODE_UPDATE_CREDITS \
	+ OCFS2_SUBALLOC_ALLOC + OCFS2_SUBALLOC_FREE)

	/* used when we don't need an allocation change for a dir extend. One
	* for the dinode, one for the new block. */
	#define OCFS2_SIMPLE_DIR_EXTEND_CREDITS (2)

	/* file update (nlink, etc) + directory mtime/ctime + dir entry block */
	#define OCFS2_LINK_CREDITS (2*OCFS2_INODE_UPDATE_CREDITS + 1)

	/* inode + dir inode (if we unlink a dir), + dir entry block + orphan
	* dir inode link */
	#define OCFS2_UNLINK_CREDITS (2 * OCFS2_INODE_UPDATE_CREDITS + 1 \
	+ OCFS2_LINK_CREDITS)

	/* dinode + orphan dir dinode + inode alloc dinode + orphan dir entry +
	* inode alloc group descriptor */
	#define OCFS2_DELETE_INODE_CREDITS (3 * OCFS2_INODE_UPDATE_CREDITS + 1 + 1)

	/* dinode update, old dir dinode update, new dir dinode update, old
	* dir dir entry, new dir dir entry, dir entry update for renaming
	* directory + target unlink */
	#define OCFS2_RENAME_CREDITS (3 * OCFS2_INODE_UPDATE_CREDITS + 3 \
	+ OCFS2_UNLINK_CREDITS)

	static inline int ocfs2_calc_extend_credits(struct super_block *sb,
	struct ocfs2_dinode *fe,
	u32 bits_wanted)
	{
	int bitmap_blocks, sysfile_bitmap_blocks, dinode_blocks;

	/* bitmap dinode, group desc. + relinked group. */
	bitmap_blocks = OCFS2_SUBALLOC_ALLOC;

	/* we might need to shift tree depth so lets assume an
	* absolute worst case of complete fragmentation. Even with
	* that, we only need one update for the dinode, and then
	* however many metadata chunks needed * a remaining suballoc
	* alloc. */
	sysfile_bitmap_blocks = 1 +
	(OCFS2_SUBALLOC_ALLOC - 1) * ocfs2_extend_meta_needed(fe);

	/* this does not include new metadata blocks, which are
	* accounted for in sysfile_bitmap_blocks. fe +
	* prev. last_eb_blk + blocks along edge of tree.
	* calc_symlink_credits passes because we just need 1
	* credit for the dinode there. */
	dinode_blocks = 1 + 1 + le16_to_cpu(fe->id2.i_list.l_tree_depth);

	return bitmap_blocks + sysfile_bitmap_blocks + dinode_blocks;
	}

	static inline int ocfs2_calc_symlink_credits(struct super_block *sb)
	{
	int blocks = OCFS2_MKNOD_CREDITS;

	/* links can be longer than one block so we may update many
	* within our single allocated extent. */
	blocks += ocfs2_clusters_to_blocks(sb, 1);

	return blocks;
	}

	static inline int ocfs2_calc_group_alloc_credits(struct super_block *sb,
	unsigned int cpg)
	{
	int blocks;
	int bitmap_blocks = OCFS2_SUBALLOC_ALLOC + 1;
	/* parent inode update + new block group header + bitmap inode update
	+ bitmap blocks affected */
	blocks = 1 + 1 + 1 + bitmap_blocks;
	return blocks;
	}

	static inline int ocfs2_calc_tree_trunc_credits(struct super_block *sb,
	unsigned int clusters_to_del,
	struct ocfs2_dinode *fe,
	struct ocfs2_extent_list *last_el)
	{
	/* for dinode + all headers in this pass + update to next leaf */
	u16 next_free = le16_to_cpu(last_el->l_next_free_rec);
	u16 tree_depth = le16_to_cpu(fe->id2.i_list.l_tree_depth);
	int credits = 1 + tree_depth + 1;
	int i;

	i = next_free - 1;
	BUG_ON(i < 0);

	/* We may be deleting metadata blocks, so metadata alloc dinode +
	one desc. block for each possible delete. */
	if (tree_depth && next_free == 1 &&
	ocfs2_rec_clusters(last_el, &last_el->l_recs[i]) == clusters_to_del)
	credits += 1 + tree_depth;

	/* update to the truncate log. */
	credits += OCFS2_TRUNCATE_LOG_UPDATE;

	return credits;
	}

	#endif /* OCFS2_JOURNAL_H */