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>

3 files changed, 15 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);
 
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));
 
diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c
index c863c8447015..58250e09eb05 100644
--- a/fs/btrfs/relocation.c
+++ b/fs/btrfs/relocation.c
@@ -1724,6 +1724,7 @@ again:
 
                         eb = read_tree_block(dest, old_bytenr, blocksize,
                                              old_ptr_gen);
+                        BUG_ON(!eb);
                         btrfs_tree_lock(eb);
                         if (cow) {
                                 ret = btrfs_cow_block(trans, dest, eb, parent,
@@ -2513,6 +2514,10 @@ static int do_relocation(struct btrfs_trans_handle *trans,
                 blocksize = btrfs_level_size(root, node->level);
                 generation = btrfs_node_ptr_generation(upper->eb, slot);
                 eb = read_tree_block(root, bytenr, blocksize, generation);
+                if (!eb) {
+                        err = -EIO;
+                        goto next;
+                }
                 btrfs_tree_lock(eb);
                 btrfs_set_lock_blocking(eb);
 
@@ -2670,6 +2675,7 @@ static int get_tree_block_key(struct reloc_control *rc,
         BUG_ON(block->key_ready);
         eb = read_tree_block(rc->extent_root, block->bytenr,
                              block->key.objectid, block->key.offset);
+        BUG_ON(!eb);
         WARN_ON(btrfs_header_level(eb) != block->level);
         if (block->level == 0)
                 btrfs_item_key_to_cpu(eb, &block->key, 0);