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

Fixes: dec214d00e ("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

fs/ext4/xattr.c

@@ -2272,8 +2272,10 @@ static struct buffer_head *ext4_xattr_get_block(struct inode *inode)
 	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;
 }