Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 9d282875 authored by Lars Ellenberg's avatar Lars Ellenberg Committed by Philipp Reisner
Browse files

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: default avatarPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: default avatarLars Ellenberg <lars.ellenberg@linbit.com>
parent 0f8488e1

drivers/block/drbd/drbd_main.c

+19 −9
Original line number Diff line number Diff line
@@ -1393,17 +1393,22 @@ static void after_state_ch(struct drbd_conf *mdev, union drbd_state os, 
	}



	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_bitmap_io(struct drbd_conf *mdev, struct drbd_work *w, int unused) 
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 @@ 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_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. */

}



/**