btrfs: send: iterate waiting dir move rbtree only once when processing refs

When processing the new references for an inode, we unnecessarily iterate
twice the waiting dir moves rbtree, once with is_waiting_for_move() and
if we found an entry in the rbtree, we iterate it again with a call to
get_waiting_dir_move(). This is pointless, we can make this simpler and
more efficient by calling only get_waiting_dir_move(), so just do that.

This patch is part of a larger patchset and the changelog of the last
patch in the series contains a sample performance test and results.
The patches that comprise the patchset are the following:

  btrfs: send: directly return from did_overwrite_ref() and simplify it
  btrfs: send: avoid unnecessary generation search at did_overwrite_ref()
  btrfs: send: directly return from will_overwrite_ref() and simplify it
  btrfs: send: avoid extra b+tree searches when checking reference overrides
  btrfs: send: remove send_progress argument from can_rmdir()
  btrfs: send: avoid duplicated orphan dir allocation and initialization
  btrfs: send: avoid unnecessary orphan dir rbtree search at can_rmdir()
  btrfs: send: reduce searches on parent root when checking if dir can be removed
  btrfs: send: iterate waiting dir move rbtree only once when processing refs
  btrfs: send: initialize all the red black trees earlier
  btrfs: send: genericize the backref cache to allow it to be reused
  btrfs: adapt lru cache to allow for 64 bits keys on 32 bits systems
  btrfs: send: cache information about created directories
  btrfs: allow a generation number to be associated with lru cache entries
  btrfs: add an api to delete a specific entry from the lru cache
  btrfs: send: use the lru cache to implement the name cache
  btrfs: send: update size of roots array for backref cache entries
  btrfs: send: cache utimes operations for directories if possible

Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

diff --git a/fs/btrfs/send.c b/fs/btrfs/send.c
index b8d80e5aeddd9537d482eed7a53532a292509ae1..0623d30fa2dca017ae9302117a1483231ccfbe60 100644 (file)
--- a/fs/btrfs/send.c
+++ b/fs/btrfs/send.c
@@ -4335,12 +4335,9 @@ static int process_recorded_refs(struct send_ctx *sctx, int *pending_move)
                                 * the source path when performing its rename
                                 * operation.
                                 */
-                               if (is_waiting_for_move(sctx, ow_inode)) {
-                                       wdm = get_waiting_dir_move(sctx,
-                                                                  ow_inode);
-                                       ASSERT(wdm);
+                               wdm = get_waiting_dir_move(sctx, ow_inode);
+                               if (wdm)
                                        wdm->orphanized = true;
-                               }
 
                                /*
                                 * Make sure we clear our orphanized inode's