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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>
This commit is contained in:
Lars Ellenberg 2010-10-14 13:57:07 +02:00 committed by Philipp Reisner
parent 0f8488e160
commit 9d282875d8
1 changed files with 18 additions and 8 deletions
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26
drivers/block/drbd/drbd_main.c
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@ -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. */
}
/**