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| author | Lars Ellenberg <lars.ellenberg@linbit.com> | 2013-03-19 18:16:42 +0100 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2013-03-22 18:13:59 -0600 |
| commit | 9114d79569a3fb858a7ecb1f21cb1dec93dc2f21 (patch) | |
| tree | 871deca58015097957ca605c55d6589f72f39297 | |
| parent | a937536b868b8369b98967929045f1df54234323 (diff) | |
| download | blackbird-op-linux-9114d79569a3fb858a7ecb1f21cb1dec93dc2f21.tar.gz blackbird-op-linux-9114d79569a3fb858a7ecb1f21cb1dec93dc2f21.zip | |
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>
| -rw-r--r-- | drivers/block/drbd/drbd_int.h | 7 | ||||
| -rw-r--r-- | drivers/block/drbd/drbd_main.c | 7 |
2 files changed, 4 insertions, 10 deletions
diff --git a/drivers/block/drbd/drbd_int.h b/drivers/block/drbd/drbd_int.h index 6b51afa1aae1..db504d021a6e 100644 --- a/drivers/block/drbd/drbd_int.h +++ b/drivers/block/drbd/drbd_int.h @@ -1148,7 +1148,6 @@ extern int drbd_bitmap_io_from_worker(struct drbd_conf *mdev, 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 @@ static inline void put_ldev(struct drbd_conf *mdev) 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 e98da675f0c1..731a28eedc56 100644 --- a/drivers/block/drbd/drbd_main.c +++ b/drivers/block/drbd/drbd_main.c @@ -3252,13 +3252,6 @@ static int w_go_diskless(struct drbd_work *w, int unused) 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. |
