ext4: fix buffer leak in ext4_xattr_get_block() on error path

commit ecaaf408478b6fb4d9986f9b6652f3824e374f4c upstream.

Fixes: dec214d00e0d ("ext4: xattr inode deduplication")
Signed-off-by: Vasily Averin <vvs@virtuozzo.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@kernel.org # 4.13
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/fs/ext4/xattr.c b/fs/ext4/xattr.c
index 30272517..e661008 100644
--- a/fs/ext4/xattr.c
+++ b/fs/ext4/xattr.c
@@ -2282,8 +2282,10 @@
 	if (!bh)
 		return ERR_PTR(-EIO);
 	error = ext4_xattr_check_block(inode, bh);
-	if (error)
+	if (error) {
+		brelse(bh);
 		return ERR_PTR(error);
+	}
 	return bh;
 }