aboutsummaryrefslogtreecommitdiffstats
path: root/fs/xfs/xfs_buf.c
diff options
context:
space:
mode:
authorJan Kara <jack@suse.cz>2012-06-06 00:32:26 +0200
committerBen Myers <bpm@sgi.com>2012-06-21 13:38:25 -0500
commitbcf62ab64d1ba257dd9d4283a077a7219a05073a (patch)
treeb4de28d5e5978de675440e966384f0c4c01ff0e3 /fs/xfs/xfs_buf.c
parent079da28c64ebeca357adae77aea3ae7160e45d98 (diff)
xfs: Fix overallocation in xfs_buf_allocate_memory()
Commit de1cbee which removed b_file_offset in favor of b_bn introduced a bug causing xfs_buf_allocate_memory() to overestimate the number of necessary pages. The problem is that xfs_buf_alloc() sets b_bn to -1 and thus effectively every buffer is straddling a page boundary which causes xfs_buf_allocate_memory() to allocate two pages and use vmalloc() for access which is unnecessary. Dave says xfs_buf_alloc() doesn't need to set b_bn to -1 anymore since the buffer is inserted into the cache only after being fully initialized now. So just make xfs_buf_alloc() fill in proper block number from the beginning. CC: David Chinner <dchinner@redhat.com> Signed-off-by: Jan Kara <jack@suse.cz> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Ben Myers <bpm@sgi.com>
Diffstat (limited to 'fs/xfs/xfs_buf.c')
-rw-r--r--fs/xfs/xfs_buf.c16
1 files changed, 2 insertions, 14 deletions
diff --git a/fs/xfs/xfs_buf.c b/fs/xfs/xfs_buf.c
index 172d3cc8f8c..a4beb421018 100644
--- a/fs/xfs/xfs_buf.c
+++ b/fs/xfs/xfs_buf.c
@@ -201,14 +201,7 @@ xfs_buf_alloc(
bp->b_length = numblks;
bp->b_io_length = numblks;
bp->b_flags = flags;
-
- /*
- * We do not set the block number here in the buffer because we have not
- * finished initialising the buffer. We insert the buffer into the cache
- * in this state, so this ensures that we are unable to do IO on a
- * buffer that hasn't been fully initialised.
- */
- bp->b_bn = XFS_BUF_DADDR_NULL;
+ bp->b_bn = blkno;
atomic_set(&bp->b_pin_count, 0);
init_waitqueue_head(&bp->b_waiters);
@@ -567,11 +560,6 @@ xfs_buf_get(
if (bp != new_bp)
xfs_buf_free(new_bp);
- /*
- * Now we have a workable buffer, fill in the block number so
- * that we can do IO on it.
- */
- bp->b_bn = blkno;
bp->b_io_length = bp->b_length;
found:
@@ -772,7 +760,7 @@ xfs_buf_get_uncached(
int error, i;
xfs_buf_t *bp;
- bp = xfs_buf_alloc(target, 0, numblks, 0);
+ bp = xfs_buf_alloc(target, XFS_BUF_DADDR_NULL, numblks, 0);
if (unlikely(bp == NULL))
goto fail;