Btrfs: fix a bug in parsing return value in logical resolve
In logical resolve, we parse extent_from_logical()'s 'ret' as a kind of flag.
It is possible to lose our errors because
(-EXXXX & BTRFS_EXTENT_FLAG_TREE_BLOCK) is true.
I'm not sure if it is on purpose, it just looks too hacky if it is.
I'd rather use a real flag and a 'ret' to catch errors.
Acked-by: Jan Schmidt <list.btrfs@jan-o-sch.net>
Signed-off-by: Liu Bo <liub.liubo@gmail.com>
diff --git a/fs/btrfs/backref.c b/fs/btrfs/backref.c
index e600857..ab286e5 100644
--- a/fs/btrfs/backref.c
+++ b/fs/btrfs/backref.c
@@ -1193,7 +1193,8 @@
* tree blocks and <0 on error.
*/
int extent_from_logical(struct btrfs_fs_info *fs_info, u64 logical,
- struct btrfs_path *path, struct btrfs_key *found_key)
+ struct btrfs_path *path, struct btrfs_key *found_key,
+ u64 *flags_ret)
{
int ret;
u64 flags;
@@ -1237,10 +1238,17 @@
(unsigned long long)found_key->objectid,
(unsigned long long)found_key->offset,
(unsigned long long)flags, item_size);
- if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK)
- return BTRFS_EXTENT_FLAG_TREE_BLOCK;
- if (flags & BTRFS_EXTENT_FLAG_DATA)
- return BTRFS_EXTENT_FLAG_DATA;
+
+ WARN_ON(!flags_ret);
+ if (flags_ret) {
+ if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK)
+ *flags_ret = BTRFS_EXTENT_FLAG_TREE_BLOCK;
+ else if (flags & BTRFS_EXTENT_FLAG_DATA)
+ *flags_ret = BTRFS_EXTENT_FLAG_DATA;
+ else
+ BUG_ON(1);
+ return 0;
+ }
return -EIO;
}
@@ -1433,15 +1441,15 @@
{
int ret;
u64 extent_item_pos;
+ u64 flags = 0;
struct btrfs_key found_key;
int search_commit_root = path->search_commit_root;
- ret = extent_from_logical(fs_info, logical, path,
- &found_key);
+ ret = extent_from_logical(fs_info, logical, path, &found_key, &flags);
btrfs_release_path(path);
if (ret < 0)
return ret;
- if (ret & BTRFS_EXTENT_FLAG_TREE_BLOCK)
+ if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK)
return -EINVAL;
extent_item_pos = logical - found_key.objectid;