btrfs: backref: Don't merge refs which are not for same block.
Old __merge_refs() in backref.c will even merge refs whose root_id are
different, which makes qgroup gives wrong result.
Fix it by checking ref_for_same_block() before any mode specific works.
Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
diff --git a/fs/btrfs/backref.c b/fs/btrfs/backref.c
index 679dc97..a3316f1 100644
--- a/fs/btrfs/backref.c
+++ b/fs/btrfs/backref.c
@@ -509,7 +509,7 @@
}
/*
- * merge two lists of backrefs and adjust counts accordingly
+ * merge backrefs and adjust counts accordingly
*
* mode = 1: merge identical keys, if key is set
* FIXME: if we add more keys in __add_prelim_ref, we can merge more here.
@@ -537,9 +537,9 @@
ref2 = list_entry(pos2, struct __prelim_ref, list);
+ if (!ref_for_same_block(ref1, ref2))
+ continue;
if (mode == 1) {
- if (!ref_for_same_block(ref1, ref2))
- continue;
if (!ref1->parent && ref2->parent) {
xchg = ref1;
ref1 = ref2;