Btrfs: add a barrier before a waitqueue_active check

We were missing wakeups on the delayed ref waitqueue due
to races on waitqueue_active.

Signed-off-by: Chris Mason <chris.mason@fusionio.com>
This commit is contained in:
Chris Mason 2012-07-25 16:03:32 -04:00
parent e9fbcb4220
commit cd1cfc4915

View File

@ -5294,6 +5294,7 @@ static noinline int check_ref_cleanup(struct btrfs_trans_handle *trans,
rb_erase(&head->node.rb_node, &delayed_refs->root);
delayed_refs->num_entries--;
smp_mb();
if (waitqueue_active(&root->fs_info->tree_mod_seq_wait))
wake_up(&root->fs_info->tree_mod_seq_wait);