Btrfs: add btrfs_search_old_slot

The tree modification log together with the current state of the tree gives
a consistent, old version of the tree. btrfs_search_old_slot is used to
search through this old version and return old (dummy!) extent buffers.
Naturally, this function cannot do any tree modifications.

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

1 files changed, 2 insertions, 0 deletions

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index e53bfb9b3915..6ba21b12cec4 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -2668,6 +2668,8 @@ int btrfs_duplicate_item(struct btrfs_trans_handle *trans,
 int btrfs_search_slot(struct btrfs_trans_handle *trans, struct btrfs_root
                       *root, struct btrfs_key *key, struct btrfs_path *p, int
                       ins_len, int cow);
+int btrfs_search_old_slot(struct btrfs_root *root, struct btrfs_key *key,
+                          struct btrfs_path *p, u64 time_seq);
 int btrfs_realloc_node(struct btrfs_trans_handle *trans,
                        struct btrfs_root *root, struct extent_buffer *parent,
                        int start_slot, int cache_only, u64 *last_ret,