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, 3 insertions, 0 deletions

diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
index 4edcbe915736..84d7ca1fe0ba 100644
--- a/fs/btrfs/ctree.c
+++ b/fs/btrfs/ctree.c
@@ -682,6 +682,8 @@ int btrfs_realloc_node(struct btrfs_trans_handle *trans,
                         if (!cur) {
                                 cur = read_tree_block(root, blocknr,
                                                          blocksize, gen);
+                                if (!cur)
+                                        return -EIO;
                         } else if (!uptodate) {
                                 btrfs_read_buffer(cur, gen);
                         }
@@ -4087,6 +4089,7 @@ find_next_key:
                 }
                 btrfs_set_path_blocking(path);
                 cur = read_node_slot(root, cur, slot);
+                BUG_ON(!cur);
 
                 btrfs_tree_lock(cur);