@@ -632,7 +632,7 @@ static int __add_delayed_refs(struct btrfs_delayed_ref_head *head, u64 seq,
struct btrfs_delayed_tree_ref *ref;
ref = btrfs_delayed_node_to_tree_ref(node);
- ret = __add_prelim_ref(prefs, ref->root, NULL,
+ ret = __add_prelim_ref(prefs, 0, NULL,
ref->level + 1, ref->parent,
node->bytenr,
node->ref_mod * sgn, GFP_ATOMIC);
@@ -664,11 +664,7 @@ static int __add_delayed_refs(struct btrfs_delayed_ref_head *head, u64 seq,
struct btrfs_delayed_data_ref *ref;
ref = btrfs_delayed_node_to_data_ref(node);
-
- key.objectid = ref->objectid;
- key.type = BTRFS_EXTENT_DATA_KEY;
- key.offset = ref->offset;
- ret = __add_prelim_ref(prefs, ref->root, &key, 0,
+ ret = __add_prelim_ref(prefs, 0, NULL, 0,
ref->parent, node->bytenr,
node->ref_mod * sgn, GFP_ATOMIC);
break;
When we do backref walking, we search firstly in queued delayed refs and then the on-disk backrefs, but we parse differently for shared references, for delayed refs we also add 'ref->root' while for on-disk backrefs we don't, this can prevent us from merging refs indexed by the same bytenr and cause find_parent_nodes() to throw a warning at 'WARN_ON(ref->count < 0)', for example, when we have a shared data extent with 'ref_cnt=1' and a delayed shared data with a BTRFS_DROP_DELAYED_REF, that happens. For shared references, no matter if it's delayed or on-disk, ref->root is not at all used, instead it's ref->parent that really matters, so this has delayed refs handled as the same way as on-disk refs. Signed-off-by: Liu Bo <bo.li.liu@oracle.com> --- v2: Fix typo of not deleting key.type and key.offset, credit goes to Filipe. fs/btrfs/backref.c | 8 ++------ 1 file changed, 2 insertions(+), 6 deletions(-)