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Commit c518d04f authored by Lars Ellenberg's avatar Lars Ellenberg Committed by Philipp Reisner
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drbd: fix race between deconfiguring and reconfiguring network 



If a drbd_nl_net_conf hits the small window between the state change
to C_STANDALONE and the corresponding cleanup in after_state_ch,
that cleanup would throw away stuff we now need again,
and later trigger BUG_ON()s.

Fixed by properly serializing the new config request with
any pending cleanup.

Signed-off-by: default avatarPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: default avatarLars Ellenberg <lars.ellenberg@linbit.com>
parent 0778286a

drivers/block/drbd/drbd_nl.c

+4 −2
Original line number Diff line number Diff line
@@ -750,14 +750,16 @@ void drbd_setup_queue_param(struct drbd_conf *mdev, unsigned int max_seg_s) __mu 
/* serialize deconfig (worker exiting, doing cleanup)

 * and reconfig (drbdsetup disk, drbdsetup net)

 *

 * wait for a potentially exiting worker, then restart it,

 * or start a new one.

 * Wait for a potentially exiting worker, then restart it,

 * or start a new one.  Flush any pending work, there may still be an

 * after_state_change queued.

 */

static void drbd_reconfig_start(struct drbd_conf *mdev)

{

	wait_event(mdev->state_wait, !test_and_set_bit(CONFIG_PENDING, &mdev->flags));

	wait_event(mdev->state_wait, !test_bit(DEVICE_DYING, &mdev->flags));

	drbd_thread_start(&mdev->worker);

	drbd_flush_workqueue(mdev);

}



/* if still unconfigured, stops worker again.