Commit d4a8c93c authored by Joel Becker's avatar Joel Becker Committed by Mark Fasheh
Browse files

ocfs2: Make cached block reads the common case. 



ocfs2_read_blocks() currently requires the CACHED flag for cached I/O.
However, that's the common case.  Let's flip it around and provide an
IGNORE_CACHE flag for the special users.  This has the added benefit of
cleaning up the code some (ignore_cache takes on its special meaning
earlier in the loop).

Signed-off-by: default avatarJoel Becker <joel.becker@oracle.com>
Signed-off-by: default avatarMark Fasheh <mfasheh@suse.com>
parent 5e0b3dec

fs/ocfs2/buffer_head_io.c

+11 −8
Original line number Diff line number Diff line
@@ -181,7 +181,8 @@ int ocfs2_read_blocks(struct inode *inode, u64 block, int nr, 
		   inode, (unsigned long long)block, nr, flags);



	BUG_ON(!inode);

	BUG_ON((flags & OCFS2_BH_READAHEAD) && !(flags & OCFS2_BH_CACHED));

	BUG_ON((flags & OCFS2_BH_READAHEAD) &&

	       (flags & OCFS2_BH_IGNORE_CACHE));



	if (bhs == NULL) {

		status = -EINVAL;
@@ -214,7 +215,7 @@ int ocfs2_read_blocks(struct inode *inode, u64 block, int nr, 
			}

		}

		bh = bhs[i];

		ignore_cache = 0;

		ignore_cache = (flags & OCFS2_BH_IGNORE_CACHE);



		/* There are three read-ahead cases here which we need to

		 * be concerned with. All three assume a buffer has
@@ -240,26 +241,27 @@ int ocfs2_read_blocks(struct inode *inode, u64 block, int nr, 
		 *    before our is-it-in-flight check.

		 */



		if (flags & OCFS2_BH_CACHED &&

		    !ocfs2_buffer_uptodate(inode, bh)) {

		if (!ignore_cache && !ocfs2_buffer_uptodate(inode, bh)) {

			mlog(ML_UPTODATE,

			     "bh (%llu), inode %llu not uptodate\n",

			     (unsigned long long)bh->b_blocknr,

			     (unsigned long long)OCFS2_I(inode)->ip_blkno);

			/* We're using ignore_cache here to say

			 * "go to disk" */

			ignore_cache = 1;

		}



		/* XXX: Can we ever get this and *not* have the cached

		 * flag set? */

		if (buffer_jbd(bh)) {

			if (!(flags & OCFS2_BH_CACHED) || ignore_cache)

			if (ignore_cache)

				mlog(ML_BH_IO, "trying to sync read a jbd "

					       "managed bh (blocknr = %llu)\n",

				     (unsigned long long)bh->b_blocknr);

			continue;

		}



		if (!(flags & OCFS2_BH_CACHED) || ignore_cache) {

		if (ignore_cache) {

			if (buffer_dirty(bh)) {

				/* This should probably be a BUG, or

				 * at least return an error. */
@@ -294,7 +296,7 @@ int ocfs2_read_blocks(struct inode *inode, u64 block, int nr, 
			 * previously read-ahead buffer may have

			 * completed I/O while we were waiting for the

			 * buffer lock. */

			if ((flags & OCFS2_BH_CACHED)

			if (!(flags & OCFS2_BH_IGNORE_CACHE)

			    && !(flags & OCFS2_BH_READAHEAD)

			    && ocfs2_buffer_uptodate(inode, bh)) {

				unlock_buffer(bh);
@@ -344,7 +346,8 @@ int ocfs2_read_blocks(struct inode *inode, u64 block, int nr, 


	mlog(ML_BH_IO, "block=(%llu), nr=(%d), cached=%s, flags=0x%x\n", 

	     (unsigned long long)block, nr,

	     (!(flags & OCFS2_BH_CACHED) || ignore_cache) ? "no" : "yes", flags);

	     ((flags & OCFS2_BH_IGNORE_CACHE) || ignore_cache) ? "no" : "yes",

	     flags);



bail:

fs/ocfs2/buffer_head_io.h

+2 −2
Original line number Diff line number Diff line
@@ -49,7 +49,7 @@ int ocfs2_read_blocks_sync(struct ocfs2_super *osb, u64 block, 
int ocfs2_write_super_or_backup(struct ocfs2_super *osb,

				struct buffer_head *bh);



#define OCFS2_BH_CACHED            1

#define OCFS2_BH_IGNORE_CACHE      1

#define OCFS2_BH_READAHEAD         8



static inline int ocfs2_read_block(struct inode *inode, u64 off,
@@ -63,7 +63,7 @@ static inline int ocfs2_read_block(struct inode *inode, u64 off, 
		goto bail;

	}



	status = ocfs2_read_blocks(inode, off, 1, bh, OCFS2_BH_CACHED);

	status = ocfs2_read_blocks(inode, off, 1, bh, 0);



bail:

	return status;

fs/ocfs2/dir.c

+1 −1
Original line number Diff line number Diff line
@@ -88,7 +88,7 @@ static struct buffer_head *ocfs2_bread(struct inode *inode, 
	struct buffer_head *bh = NULL;

	int tmperr;

	u64 p_blkno;

	int readflags = OCFS2_BH_CACHED;

	int readflags = 0;



	if (reada)

		readflags |= OCFS2_BH_READAHEAD;

fs/ocfs2/inode.c

+2 −1
Original line number Diff line number Diff line
@@ -461,7 +461,8 @@ static int ocfs2_read_locked_inode(struct inode *inode, 
	}



	if (can_lock)

		status = ocfs2_read_blocks(inode, args->fi_blkno, 1, &bh, 0);

		status = ocfs2_read_blocks(inode, args->fi_blkno, 1, &bh,

					   OCFS2_BH_IGNORE_CACHE);

	else

		status = ocfs2_read_blocks_sync(osb, args->fi_blkno, 1, &bh);

	if (status < 0) {

fs/ocfs2/journal.c

+2 −1
Original line number Diff line number Diff line
@@ -1134,7 +1134,8 @@ static int ocfs2_read_journal_inode(struct ocfs2_super *osb, 
	}

	SET_INODE_JOURNAL(inode);



	status = ocfs2_read_blocks(inode, OCFS2_I(inode)->ip_blkno, 1, bh, 0);

	status = ocfs2_read_blocks(inode, OCFS2_I(inode)->ip_blkno, 1, bh,

				   OCFS2_BH_IGNORE_CACHE);

	if (status < 0) {

		mlog_errno(status);

		goto bail;

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