btrfs-progs: pass up return value of walk_down_tree

Pass up return value of walk_down_tree, so the caller can handle it.
This also fixes a segfault when read_tree_block fails with NULL returned.

Signed-off-by: Lin Ming <mlin@kernel.org>
Signed-off-by: David Sterba <dsterba@suse.cz>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>

diff --git a/cmds-check.c b/cmds-check.c
index d034446..cc9606c 100644 (file)
--- a/cmds-check.c
+++ b/cmds-check.c
@@ -1221,7 +1221,7 @@ static int walk_down_tree(struct btrfs_root *root, struct btrfs_path *path,
        struct extent_buffer *next;
        struct extent_buffer *cur;
        u32 blocksize;
-       int ret;
+       int ret, err = 0;
        u64 refs;
 
        WARN_ON(*level < 0);
@@ -1229,14 +1229,18 @@ static int walk_down_tree(struct btrfs_root *root, struct btrfs_path *path,
        ret = btrfs_lookup_extent_info(NULL, root,
                                       path->nodes[*level]->start,
                                       *level, 1, &refs, NULL);
-       if (ret < 0)
+       if (ret < 0) {
+               err = ret;
                goto out;
+       }
 
        if (refs > 1) {
                ret = enter_shared_node(root, path->nodes[*level]->start,
                                        refs, wc, *level);
-               if (ret > 0)
+               if (ret > 0) {
+                       err = ret;
                        goto out;
+               }
        }
 
        while (*level >= 0) {
@@ -1276,6 +1280,10 @@ static int walk_down_tree(struct btrfs_root *root, struct btrfs_path *path,
                        reada_walk_down(root, cur, path->slots[*level]);
                        next = read_tree_block(root, bytenr, blocksize,
                                               ptr_gen);
+                       if (!next) {
+                               err = -EIO;
+                               goto out;
+                       }
                }
 
                *level = *level - 1;
@@ -1285,7 +1293,7 @@ static int walk_down_tree(struct btrfs_root *root, struct btrfs_path *path,
        }
 out:
        path->slots[*level] = btrfs_header_nritems(path->nodes[*level]);
-       return 0;
+       return err;
 }
 
 static int walk_up_tree(struct btrfs_root *root, struct btrfs_path *path,