journal.h

ocfs1.2.7 源码

			   ocfs2_inode_fully_checkpointed(inode));
	}
}

/*
 *  Transaction Handling:
 *  Manage the lifetime of a transaction handle.
 *
 *  ocfs2_alloc_handle     - Only allocate a handle so we can start putting
 *                          cluster locks on it. To actually change blocks,
 *                          call ocfs2_start_trans with the handle returned
 *                          from this function. You may call ocfs2_commit_trans
 *                           at any time in the lifetime of a 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.
 *  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_handle_add_lock  - Sometimes we need to delay lock release
 *                          until after a transaction has been completed. Use
 *                          ocfs2_handle_add_lock to indicate that a lock needs
 *                          to be released at the end of that handle. Locks
 *                          will be released in the order that they are added.
 *  ocfs2_handle_add_inode - Add a locked inode to a transaction.
 */

/* 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. */
struct ocfs2_journal_handle *ocfs2_alloc_handle(struct ocfs2_super *osb);
struct ocfs2_journal_handle *ocfs2_start_trans(struct ocfs2_super *osb,
					struct ocfs2_journal_handle *handle,
					int max_buffs);
void                 ocfs2_commit_trans(struct ocfs2_journal_handle *handle);
int                  ocfs2_extend_trans(struct ocfs2_journal_handle *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(struct ocfs2_journal_handle *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(struct ocfs2_journal_handle *handle,
					 struct buffer_head *bh);
int                  ocfs2_handle_add_lock(struct ocfs2_journal_handle *handle,
					   struct inode *inode);
/*
 * Use this to protect from other processes reading buffer state while
 * it's in flight.
 */
void                 ocfs2_handle_add_inode(struct ocfs2_journal_handle *handle,
					    struct inode *inode);

/*
 *  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

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

/* 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)

/* 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 &&
	    le32_to_cpu(last_el->l_recs[i].e_clusters) == clusters_to_del)
		credits += 1 + tree_depth;

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

	return credits;
}

#endif /* OCFS2_JOURNAL_H */