btrfs: fix iterator with update error in backref.c

Fix the following error:

fs/btrfs/backref.c:565:1-20: iterator with update on line 577

Fixes: a7ca422('btrfs: use list_for_each_entry* in backref.c')
Signed-off-by: Geliang Tang <geliangtang@163.com>
Signed-off-by: David Sterba <dsterba@suse.com>

diff --git a/fs/btrfs/backref.c b/fs/btrfs/backref.c
index 08405a3da6b1baf9a382327d72dc5a5a85d0c68d..b90cd3776f8e0a41635ce7cf5447e7b9652e6cca 100644 (file)
--- a/fs/btrfs/backref.c
+++ b/fs/btrfs/backref.c
@@ -560,13 +560,13 @@ static int __add_missing_keys(struct btrfs_fs_info *fs_info,
  */
 static void __merge_refs(struct list_head *head, int mode)
 {
-       struct __prelim_ref *ref1;
+       struct __prelim_ref *pos1;
 
-       list_for_each_entry(ref1, head, list) {
-               struct __prelim_ref *ref2 = ref1, *tmp;
+       list_for_each_entry(pos1, head, list) {
+               struct __prelim_ref *pos2 = pos1, *tmp;
 
-               list_for_each_entry_safe_continue(ref2, tmp, head, list) {
-                       struct __prelim_ref *xchg;
+               list_for_each_entry_safe_continue(pos2, tmp, head, list) {
+                       struct __prelim_ref *xchg, *ref1 = pos1, *ref2 = pos2;
                        struct extent_inode_elem *eie;
 
                        if (!ref_for_same_block(ref1, ref2))