diff options
Diffstat (limited to 'drivers/block/drbd/drbd_actlog.c')
| -rw-r--r-- | drivers/block/drbd/drbd_actlog.c | 18 |
1 files changed, 10 insertions, 8 deletions
diff --git a/drivers/block/drbd/drbd_actlog.c b/drivers/block/drbd/drbd_actlog.c index 933404e6ba28..aeb483daea06 100644 --- a/drivers/block/drbd/drbd_actlog.c +++ b/drivers/block/drbd/drbd_actlog.c @@ -212,13 +212,22 @@ void drbd_al_begin_io(struct drbd_conf *mdev, struct drbd_interval *i) unsigned first = i->sector >> (AL_EXTENT_SHIFT-9); unsigned last = (i->sector + (i->size >> 9) - 1) >> (AL_EXTENT_SHIFT-9); unsigned enr; + bool locked = false; + D_ASSERT(atomic_read(&mdev->local_cnt) > 0); for (enr = first; enr <= last; enr++) wait_event(mdev->al_wait, _al_get(mdev, enr) != NULL); - if (mdev->act_log->pending_changes) { + /* Serialize multiple transactions. + * This uses test_and_set_bit, memory barrier is implicit. + */ + wait_event(mdev->al_wait, + mdev->act_log->pending_changes == 0 || + (locked = lc_try_lock_for_transaction(mdev->act_log))); + + if (locked) { /* drbd_al_write_transaction(mdev,al_ext,enr); * recurses into generic_make_request(), which * disallows recursion, bios being serialized on the @@ -226,13 +235,6 @@ void drbd_al_begin_io(struct drbd_conf *mdev, struct drbd_interval *i) * we have to delegate updates to the activity log * to the worker thread. */ - /* Serialize multiple transactions. - * This uses test_and_set_bit, memory barrier is implicit. - * Optimization potential: - * first check for transaction number > old transaction number, - * so not all waiters have to lock/unlock. */ - wait_event(mdev->al_wait, lc_try_lock_for_transaction(mdev->act_log)); - /* Double check: it may have been committed by someone else, * while we have been waiting for the lock. */ if (mdev->act_log->pending_changes) { |