[PATCH 5/7] Btrfs: leave critical region in btrfs_find_all_roots as soon as possible

[Jan Schmidt <list.btrfs@jan-o-sch.net>]

When delayed refs exist, btrfs_find_all_roots used to hold the delayed ref
mutex way longer than actually required. We ought to drop it immediately
after we're done collecting all the delayed refs.

Signed-off-by: Jan Schmidt <list.btrfs@jan-o-sch.net>
---
 fs/btrfs/backref.c |    3 +--
 1 files changed, 1 insertions(+), 2 deletions(-)

diff --git a/fs/btrfs/backref.c b/fs/btrfs/backref.c
index cf0df90..a383c18 100644
--- a/fs/btrfs/backref.c
+++ b/fs/btrfs/backref.c
@@ -839,6 +839,7 @@ again:
 			}
 			ret = __add_delayed_refs(head, delayed_ref_seq,
 						 &prefs_delayed);
+			mutex_unlock(&head->mutex);
 			if (ret) {
 				spin_unlock(&delayed_refs->lock);
 				goto out;
@@ -932,8 +933,6 @@ again:
 	}
 
 out:
-	if (head)
-		mutex_unlock(&head->mutex);
 	btrfs_free_path(path);
 	while (!list_empty(&prefs)) {
 		ref = list_first_entry(&prefs, struct __prelim_ref, list);
-- 
1.7.3.4