drbd: drop wrong debug asserts, fix recently introduced race
commit 2372c38caadeaebc68a5ee190782c2a0df01edc3
drbd: fix for possible deadlock on IO error during resync
introduced a new ASSERT, which turns out to be wrong. Drop it.
Also serialize the state change to D_DISKLESS with the after state
change work of the -> D_FAILED transition, don't open a new race.
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
diff --git a/drivers/block/drbd/drbd_main.c b/drivers/block/drbd/drbd_main.c
index f89b974..342574f 100644
--- a/drivers/block/drbd/drbd_main.c
+++ b/drivers/block/drbd/drbd_main.c
@@ -1393,17 +1393,22 @@
}
if (os.disk > D_DISKLESS && ns.disk == D_DISKLESS) {
- int c = atomic_read(&mdev->local_cnt);
+ /* We must still be diskless,
+ * re-attach has to be serialized with this! */
+ if (mdev->state.disk != D_DISKLESS)
+ dev_err(DEV,
+ "ASSERT FAILED: disk is %s while going diskless\n",
+ drbd_disk_str(mdev->state.disk));
+ /* we cannot assert local_cnt == 0 here, as get_ldev_if_state
+ * will inc/dec it frequently. Since we became D_DISKLESS, no
+ * one has touched the protected members anymore, though, so we
+ * are safe to free them here. */
if (drbd_send_state(mdev))
dev_warn(DEV, "Notified peer that I detached my disk.\n");
else
dev_err(DEV, "Sending state for detach failed\n");
- if (c != 0) {
- dev_err(DEV, "Logic bug, local_cnt=%d, but should be 0\n", c);
- wait_event(mdev->misc_wait, !atomic_read(&mdev->local_cnt));
- }
lc_destroy(mdev->resync);
mdev->resync = NULL;
lc_destroy(mdev->act_log);
@@ -3723,8 +3728,10 @@
static int w_go_diskless(struct drbd_conf *mdev, struct drbd_work *w, int unused)
{
D_ASSERT(mdev->state.disk == D_FAILED);
- D_ASSERT(atomic_read(&mdev->local_cnt) == 0);
-
+ /* we cannot assert local_cnt == 0 here, as get_ldev_if_state will
+ * inc/dec it frequently. Once we are D_DISKLESS, no one will touch
+ * the protected members anymore, though, so in the after_state_ch work
+ * it will be safe to free them. */
drbd_force_state(mdev, NS(disk, D_DISKLESS));
clear_bit(GO_DISKLESS, &mdev->flags);
@@ -3735,7 +3742,10 @@
{
D_ASSERT(mdev->state.disk == D_FAILED);
if (!test_and_set_bit(GO_DISKLESS, &mdev->flags))
- drbd_queue_work_front(&mdev->data.work, &mdev->go_diskless);
+ drbd_queue_work(&mdev->data.work, &mdev->go_diskless);
+ /* don't drbd_queue_work_front,
+ * we need to serialize with the after_state_ch work
+ * of the -> D_FAILED transition. */
}
/**
