diff options
| -rw-r--r-- | fs/btrfs/locking.c | 14 |
1 files changed, 9 insertions, 5 deletions
diff --git a/fs/btrfs/locking.c b/fs/btrfs/locking.c index 272f911203ff..a44eff074805 100644 --- a/fs/btrfs/locking.c +++ b/fs/btrfs/locking.c @@ -78,13 +78,15 @@ void btrfs_clear_lock_blocking_rw(struct extent_buffer *eb, int rw) write_lock(&eb->lock); WARN_ON(atomic_read(&eb->spinning_writers)); atomic_inc(&eb->spinning_writers); - if (atomic_dec_and_test(&eb->blocking_writers)) + if (atomic_dec_and_test(&eb->blocking_writers) && + waitqueue_active(&eb->write_lock_wq)) wake_up(&eb->write_lock_wq); } else if (rw == BTRFS_READ_LOCK_BLOCKING) { BUG_ON(atomic_read(&eb->blocking_readers) == 0); read_lock(&eb->lock); atomic_inc(&eb->spinning_readers); - if (atomic_dec_and_test(&eb->blocking_readers)) + if (atomic_dec_and_test(&eb->blocking_readers) && + waitqueue_active(&eb->read_lock_wq)) wake_up(&eb->read_lock_wq); } return; @@ -199,7 +201,8 @@ void btrfs_tree_read_unlock_blocking(struct extent_buffer *eb) } btrfs_assert_tree_read_locked(eb); WARN_ON(atomic_read(&eb->blocking_readers) == 0); - if (atomic_dec_and_test(&eb->blocking_readers)) + if (atomic_dec_and_test(&eb->blocking_readers) && + waitqueue_active(&eb->read_lock_wq)) wake_up(&eb->read_lock_wq); atomic_dec(&eb->read_locks); } @@ -247,8 +250,9 @@ void btrfs_tree_unlock(struct extent_buffer *eb) if (blockers) { WARN_ON(atomic_read(&eb->spinning_writers)); atomic_dec(&eb->blocking_writers); - smp_wmb(); - wake_up(&eb->write_lock_wq); + smp_mb(); + if (waitqueue_active(&eb->write_lock_wq)) + wake_up(&eb->write_lock_wq); } else { WARN_ON(atomic_read(&eb->spinning_writers) != 1); atomic_dec(&eb->spinning_writers); |