Re: [PATCH 3.9-stable ]drbd: fix for deadlock when using automaticsplit-brain-recovery

From: Luis Henriques
Date: Tue May 14 2013 - 08:57:04 EST


On Thu, May 09, 2013 at 08:14:47AM +0900, Jonghwan Choi wrote:
> This patch looks like it should be in the 3.9-stable tree, should we apply
> it?

This seems to be applicable to older kernels as well (starting with
3.0 at least).

I'm queuing it for 3.5.

Cheers,
--
Luis

>
> ------------------
>
> From: "Philipp Reisner <philipp.reisner@xxxxxxxxxx>"
>
> commit 7c689e63a847316c1b2500f86891b0a574ce7e69 upstream
>
> With an automatic after split-brain recovery policy of
> "after-sb-1pri call-pri-lost-after-sb",
> when trying to drbd_set_role() to R_SECONDARY,
> we run into a deadlock.
>
> This was first recognized and supposedly fixed by
> 2009-06-10 "Fixed a deadlock when using automatic split brain recovery when
> both nodes are"
> replacing drbd_set_role() with drbd_change_state() in that code-path,
> but the first hunk of that patch forgets to remove the drbd_set_role().
>
> We apparently only ever tested the "two primaries" case.
>
> Cc: <stable@xxxxxxxxxxxxxxx> # 3.9.x: ef57f9e6: drbd: Fix build error
> Signed-off-by: Philipp Reisner <philipp.reisner@xxxxxxxxxx>
> Signed-off-by: Lars Ellenberg <lars.ellenberg@xxxxxxxxxx>
> Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
> Signed-off-by: Jonghwan Choi <jhbird.choi@xxxxxxxxxxx>
> ---
> drivers/block/drbd/drbd_receiver.c | 1 -
> 1 file changed, 1 deletion(-)
>
> diff --git a/drivers/block/drbd/drbd_receiver.c
> b/drivers/block/drbd/drbd_receiver.c
> index a9eccfc..5105f43 100644
> --- a/drivers/block/drbd/drbd_receiver.c
> +++ b/drivers/block/drbd/drbd_receiver.c
> @@ -2661,7 +2661,6 @@ static int drbd_asb_recover_1p(struct drbd_conf *mdev)
> __must_hold(local)
> if (hg == -1 && mdev->state.role == R_PRIMARY) {
> enum drbd_state_rv rv2;
>
> - drbd_set_role(mdev, R_SECONDARY, 0);
> /* drbd_change_state() does not sleep while in
> SS_IN_TRANSIENT_STATE,
> * we might be here in C_WF_REPORT_PARAMS which is
> transient.
> * we do not need to wait for the after state
> change work either. */
> --
> 1.7.9.5
>
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