Btrfs: add btrfs_next_old_leaf

To make sense of the tree mod log, the backref walker not only needs
btrfs_search_old_slot, but it also called btrfs_next_leaf, which in turn was
calling btrfs_search_slot. This obviously didn't give the correct result.

This commit adds btrfs_next_old_leaf, a drop-in replacement for
btrfs_next_leaf with a time_seq parameter. If it is zero, it behaves exactly
like btrfs_next_leaf. If it is non-zero, it will use btrfs_search_old_slot
with this time_seq parameter.

Signed-off-by: Jan Schmidt <list.btrfs@jan-o-sch.net>

1 files changed, 10 insertions, 1 deletions

diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
index 50d7c99ddce7..cb76b2a1b908 100644
--- a/fs/btrfs/ctree.c
+++ b/fs/btrfs/ctree.c
@@ -5017,6 +5017,12 @@ next:
  */
 int btrfs_next_leaf(struct btrfs_root *root, struct btrfs_path *path)
 {
+        return btrfs_next_old_leaf(root, path, 0);
+}
+
+int btrfs_next_old_leaf(struct btrfs_root *root, struct btrfs_path *path,
+                        u64 time_seq)
+{
         int slot;
         int level;
         struct extent_buffer *c;
@@ -5041,7 +5047,10 @@ again:
         path->keep_locks = 1;
         path->leave_spinning = 1;
 
-        ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
+        if (time_seq)
+                ret = btrfs_search_old_slot(root, &key, path, time_seq);
+        else
+                ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
         path->keep_locks = 0;
 
         if (ret < 0)