Btrfs: check return value of read_tree_block()

This patch is checking return value of read_tree_block(),
and if it is NULL, error processing.

Signed-off-by: Tsutomu Itoh <t-itoh@jp.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>

1 files changed, 6 insertions, 0 deletions

diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index a6a8159c5d1e..5bc658a9d85c 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -6067,6 +6067,8 @@ static noinline int do_walk_down(struct btrfs_trans_handle *trans,
                 if (reada && level == 1)
                         reada_walk_down(trans, root, wc, path);
                 next = read_tree_block(root, bytenr, blocksize, generation);
+                if (!next)
+                        return -EIO;
                 btrfs_tree_lock(next);
                 btrfs_set_lock_blocking(next);
         }
@@ -7937,6 +7939,10 @@ static noinline int relocate_one_extent(struct btrfs_root *extent_root,
 
                         eb = read_tree_block(found_root, block_start,
                                              block_size, 0);
+                        if (!eb) {
+                                ret = -EIO;
+                                goto out;
+                        }
                         btrfs_tree_lock(eb);
                         BUG_ON(level != btrfs_header_level(eb));