From: Valentin Vidic <Valentin.Vidic@CARNet.hr>
To: "Roger Pau Monné" <roger.pau@citrix.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
Jens Axboe <axboe@kernel.dk>,
xen-devel@lists.xenproject.org, linux-block@vger.kernel.org,
linux-kernel@vger.kernel.org, stable@vger.kernel.org,
drbd-user@lists.linbit.com
Subject: Re: [PATCH] xen-blkback: Switch to closed state after releasing the backing device
Date: Fri, 7 Sep 2018 13:15:19 +0200 [thread overview]
Message-ID: <20180907111519.GJ26705@gavran.carpriv.carnet.hr> (raw)
In-Reply-To: <20180907104309.z4jsga5hcnphwxu7@mac.bytemobile.com>
On Fri, Sep 07, 2018 at 12:43:09PM +0200, Roger Pau Monné wrote:
> I would prefer if you could avoid open-coding this here, and instead
> use xen_vbd_create or similar. I would also prefer that the call to
> xen_vbd_create in backend_changed was removed and we had a single call
> to xen_vbd_create that's used for both initial device connection and
> reconnection.
>
> Also, I think this could cause issues if for some reason the frontend
> switches to state 'Connected' before hotplug scripts have run, in
> which case you would try to open an unexpected device because pdevice
> won't be correctly set.
Sure, this is just to test if the idea would work and needs a lot of
cleanup. Unfortunately it does not seem to help with the original
problem because this case is not executed on VM shutdown:
case XenbusStateClosed:
xen_blkif_disconnect(be->blkif);
xen_vbd_free(&be->blkif->vbd);
xenbus_switch_state(dev, XenbusStateClosed);
Instead xen_vbd_free gets run from a different code path after the
remove script has already failed:
[ 337.407634] block drbd0: State change failed: Device is held open by someone
[ 337.407673] block drbd0: state = { cs:Connected ro:Primary/Secondary ds:UpToDate/UpToDate r----- }
[ 337.407713] block drbd0: wanted = { cs:Connected ro:Secondary/Secondary ds:UpToDate/UpToDate r----- }
...
[ 340.109459] Workqueue: events xen_blkif_deferred_free [xen_blkback]
[ 340.109461] 0000000000000000 ffffffff81331e54 ffff883f84d19d38 ffff883f84d19d32
[ 340.109463] ffffffffc058169e ffff883f84d19d88 ffff883f84d19d20 ffffffffc05816f7
[ 340.109465] ffff883f84d19d88 ffff883f87b5a900 ffffffff81092fea 0000000088ec3080
[ 340.109467] Call Trace:
[ 340.109471] [<ffffffff81331e54>] ? dump_stack+0x5c/0x78
[ 340.109473] [<ffffffffc058169e>] ? xen_vbd_free.isra.9+0x2e/0x60 [xen_blkback]
[ 340.109475] [<ffffffffc05816f7>] ? xen_blkif_deferred_free+0x27/0x70 [xen_blkback]
[ 340.109477] [<ffffffff81092fea>] ? process_one_work+0x18a/0x420
[ 340.109479] [<ffffffff810932cd>] ? worker_thread+0x4d/0x490
[ 340.109480] [<ffffffff81093280>] ? process_one_work+0x420/0x420
[ 340.109482] [<ffffffff81099329>] ? kthread+0xd9/0xf0
[ 340.109484] [<ffffffff81099250>] ? kthread_park+0x60/0x60
[ 340.109486] [<ffffffff81615df7>] ? ret_from_fork+0x57/0x70
--
Valentin
prev parent reply other threads:[~2018-09-07 11:15 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-08-29 6:52 [PATCH] xen-blkback: Switch to closed state after releasing the backing device Valentin Vidic
2018-08-29 8:16 ` Juergen Gross
2018-08-29 8:27 ` Valentin Vidic
2018-08-29 8:43 ` Juergen Gross
2018-08-29 9:23 ` Valentin Vidic
2018-08-29 9:29 ` Juergen Gross
2018-09-05 10:36 ` Roger Pau Monné
2018-09-05 16:27 ` Valentin Vidic
2018-09-06 16:14 ` Roger Pau Monné
2018-09-06 22:03 ` Valentin Vidic
2018-09-07 12:03 ` [DRBD-user] " Lars Ellenberg
2018-09-07 12:13 ` Valentin Vidic
2018-09-07 13:28 ` Lars Ellenberg
2018-09-07 16:45 ` Valentin Vidic
2018-09-07 17:14 ` Valentin Vidic
2018-09-08 7:34 ` Valentin Vidic
2018-09-10 12:45 ` Lars Ellenberg
2018-09-10 13:22 ` Valentin Vidic
2018-09-10 15:00 ` Roger Pau Monné
2018-09-10 16:18 ` Valentin Vidic
2018-09-13 15:08 ` Roger Pau Monné
2018-09-14 11:49 ` Valentin Vidic
2018-09-14 16:18 ` Roger Pau Monné
[not found] ` <20180905113515.GU26705@gavran.carpriv.carnet.hr>
2018-09-05 16:28 ` Valentin Vidic
2018-09-06 16:29 ` Roger Pau Monné
2018-09-06 22:19 ` Valentin Vidic
2018-09-07 7:15 ` Roger Pau Monné
2018-09-07 7:23 ` Valentin Vidic
2018-09-07 7:54 ` Roger Pau Monné
2018-09-07 10:20 ` Valentin Vidic
2018-09-07 10:43 ` Roger Pau Monné
2018-09-07 11:15 ` Valentin Vidic [this message]
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