[PATCH 1/2] xfs: don't send null bp to xfs_trans_brelse()

[Eric Sandeen]

In this case, if bp is NULL, error is set, and we send a
NULL bp to xfs_trans_brelse, which will try to dereference it.

Test whether we actually have a buffer before we try to
free it.

Coverity spotted this.

Signed-off-by: Eric Sandeen <sandeen at redhat.com>
---

diff --git a/fs/xfs/libxfs/xfs_da_btree.c b/fs/xfs/libxfs/xfs_da_btree.c
index 2c42ae2..fd82753 100644
--- a/fs/xfs/libxfs/xfs_da_btree.c
+++ b/fs/xfs/libxfs/xfs_da_btree.c
@@ -2563,7 +2563,8 @@ xfs_da_get_buf(
 				    mapp, nmap, 0);
 	error = bp ? bp->b_error : -EIO;
 	if (error) {
-		xfs_trans_brelse(trans, bp);
+		if (bp)
+			xfs_trans_brelse(trans, bp);
 		goto out_free;
 	}