When the btrfs_read_fs_root() function is searching a ROOT_ITEM with
location key offset other than -1, it currently fails via BUG_ON.
The offset can have other value than -1, though. This can happen for
example if a subvolume is renamed:
$ btrfs subvolume create X && sync
Create subvolume './X'
$ btrfs inspect-internal dump-tree /dev/root | grep -B 2 'name: X$
location key (270 ROOT_ITEM 18446744073709551615) type DIR
transid 283 data_len 0 name_len 1
name: X
$ mv X Y && sync
$ btrfs inspect-internal dump-tree /dev/root | grep -B 2 'name: Y$
location key (270 ROOT_ITEM 0) type DIR
transid 285 data_len 0 name_len 1
name: Y
As can be seen the offset changed from -1ULL to 0.
Do not fail in this case.
Signed-off-by: Marek Behún
Cc: David Sterba
Cc: Qu Wenruo
Cc: Tom Rini
---
kernel-shared/disk-io.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/kernel-shared/disk-io.c b/kernel-shared/disk-io.c
index 6f584986..ba8ffd8b 100644
--- a/kernel-shared/disk-io.c
+++ b/kernel-shared/disk-io.c
@@ -752,8 +752,7 @@ struct btrfs_root *btrfs_read_fs_root(struct btrfs_fs_info
*fs_info,
return fs_info->free_space_root ? fs_info->free_space_root :
ERR_PTR(-ENOENT);
- BUG_ON(location->objectid == BTRFS_TREE_RELOC_OBJECTID ||
- location->offset != (u64)-1);
+ BUG_ON(location->objectid == BTRFS_TREE_RELOC_OBJECTID);
node = rb_search(_info->fs_root_tree, (void *),
btrfs_fs_roots_compare_objectids, NULL);
--
2.26.2
