xfs: Correctly invert xfs_buftarg LRU isolation logic
commit 19957a181608d25c8f4136652d0ea00b3738972d upstream.
Due to an inverted logic mistake in xfs_buftarg_isolate()
the xfs_buffers with zero b_lru_ref will take another trip
around LRU, while isolating buffers with non-zero b_lru_ref.
Additionally those isolated buffers end up right back on the LRU
once they are released, because b_lru_ref remains elevated.
Fix that circuitous route by leaving them on the LRU
as originally intended.
Signed-off-by: Vratislav Bendel <vbendel@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Alex Lyakas <alex@zadara.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/fs/xfs/xfs_buf.c b/fs/xfs/xfs_buf.c
index 3f45d98..6517553 100644
--- a/fs/xfs/xfs_buf.c
+++ b/fs/xfs/xfs_buf.c
@@ -1674,7 +1674,7 @@
* zero. If the value is already zero, we need to reclaim the
* buffer, otherwise it gets another trip through the LRU.
*/
- if (!atomic_add_unless(&bp->b_lru_ref, -1, 0)) {
+ if (atomic_add_unless(&bp->b_lru_ref, -1, 0)) {
spin_unlock(&bp->b_lock);
return LRU_ROTATE;
}