drbd: cleanup bogus assert message
This fixes ASSERT( mdev->state.disk == D_FAILED ) in drivers/block/drbd/drbd_main.c
When we detach from local disk, we let the local refcount hit zero twice.
First, we transition to D_FAILED, so we won't give out new references
to incoming requests; we still may give out *internal* references, though.
Once the refcount hits zero [1] while in D_FAILED, we queue a transition
to D_DISKLESS to our worker. We need to queue it, because we may be in
atomic context when putting the reference.
Once the transition to D_DISKLESS actually happened [2] from worker context,
we don't give out new internal references either.
Between hitting zero the first time [1] and actually transition to
D_DISKLESS [2], there may be a few very short lived internal get/put,
so we may hit zero more than once while being in D_FAILED, or even see a
race where a an internal get_ldev() happened while D_FAILED, but the
corresponding put_ldev() happens just after the transition to D_DISKLESS.
That's why we have the additional test_and_set_bit(GO_DISKLESS,);
and that's why the assert was placed wrong.
Since there was exactly one code path left to drbd_go_diskless(),
and that checks already for D_FAILED, drop that assert,
and fold in the drbd_queue_work().
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
diff --git a/drivers/block/drbd/drbd_int.h b/drivers/block/drbd/drbd_int.h
index 6b51afa..db504d0 100644
--- a/drivers/block/drbd/drbd_int.h
+++ b/drivers/block/drbd/drbd_int.h
@@ -1148,7 +1148,6 @@
char *why, enum bm_flag flags);
extern int drbd_bmio_set_n_write(struct drbd_conf *mdev);
extern int drbd_bmio_clear_n_write(struct drbd_conf *mdev);
-extern void drbd_go_diskless(struct drbd_conf *mdev);
extern void drbd_ldev_destroy(struct drbd_conf *mdev);
/* Meta data layout
@@ -2053,9 +2052,11 @@
if (mdev->state.disk == D_DISKLESS)
/* even internal references gone, safe to destroy */
drbd_ldev_destroy(mdev);
- if (mdev->state.disk == D_FAILED)
+ if (mdev->state.disk == D_FAILED) {
/* all application IO references gone. */
- drbd_go_diskless(mdev);
+ if (!test_and_set_bit(GO_DISKLESS, &mdev->flags))
+ drbd_queue_work(&mdev->tconn->sender_work, &mdev->go_diskless);
+ }
wake_up(&mdev->misc_wait);
}
}
diff --git a/drivers/block/drbd/drbd_main.c b/drivers/block/drbd/drbd_main.c
index e98da67..731a28e 100644
--- a/drivers/block/drbd/drbd_main.c
+++ b/drivers/block/drbd/drbd_main.c
@@ -3252,13 +3252,6 @@
return 0;
}
-void drbd_go_diskless(struct drbd_conf *mdev)
-{
- D_ASSERT(mdev->state.disk == D_FAILED);
- if (!test_and_set_bit(GO_DISKLESS, &mdev->flags))
- drbd_queue_work(&mdev->tconn->sender_work, &mdev->go_diskless);
-}
-
/**
* drbd_queue_bitmap_io() - Queues an IO operation on the whole bitmap
* @mdev: DRBD device.