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| author | Jan Kara <jack@suse.cz> | 2012-06-06 00:32:26 +0200 |
|---|---|---|
| committer | Ben Myers <bpm@sgi.com> | 2012-06-21 14:20:36 -0500 |
| commit | 59c84ed0ddc11f1823b4a33ace4fbcc948261bb2 (patch) | |
| tree | 32d64523ae5c46b4959876a3d6b498adb6452dbc | |
| parent | 76d095388b040229ea1aad7dea45be0cfa20f589 (diff) | |
| download | linux-59c84ed0ddc11f1823b4a33ace4fbcc948261bb2.tar.gz linux-59c84ed0ddc11f1823b4a33ace4fbcc948261bb2.tar.bz2 linux-59c84ed0ddc11f1823b4a33ace4fbcc948261bb2.zip | |
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>
| -rw-r--r-- | fs/xfs/xfs_buf.c | 16 |
1 files changed, 2 insertions, 14 deletions
diff --git a/fs/xfs/xfs_buf.c b/fs/xfs/xfs_buf.c index 172d3cc8f8cb..a4beb421018a 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; |