From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Date: Wed, 5 Sep 2018 18:27:56 +0200 From: Valentin Vidic To: Roger Pau =?iso-8859-1?Q?Monn=E9?= Cc: Konrad Rzeszutek Wilk , Jens Axboe , xen-devel@lists.xenproject.org, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org, drbd-user@lists.linbit.com Message-ID: <20180905162756.GA26705@gavran.carpriv.carnet.hr> References: <20180829065214.23546-1-Valentin.Vidic@CARNet.hr> <20180905103649.edugijsjx4v2fbxd@mac.bytemobile.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 In-Reply-To: <20180905103649.edugijsjx4v2fbxd@mac.bytemobile.com> Subject: Re: [PATCH] xen-blkback: Switch to closed state after releasing the backing device List-ID: On Wed, Sep 05, 2018 at 12:36:49PM +0200, Roger Pau Monn=E9 wrote: > On Wed, Aug 29, 2018 at 08:52:14AM +0200, Valentin Vidic wrote: > > Switching to closed state earlier can cause the block-drbd > > script to fail with 'Device is held open by someone': > >=20 > > root: /etc/xen/scripts/block-drbd: remove XENBUS_PATH=3Dbackend/vbd/6= /51712 > > kernel: [ 2222.278235] block drbd6: State change failed: Device is he= ld open by someone > > kernel: [ 2222.278304] block drbd6: state =3D { cs:Connected ro:Pri= mary/Secondary ds:UpToDate/UpToDate r----- } > > kernel: [ 2222.278340] block drbd6: wanted =3D { cs:Connected ro:Sec= ondary/Secondary ds:UpToDate/UpToDate r----- } > > root: /etc/xen/scripts/block-drbd: Writing backend/vbd/6/51712/hotplu= g-error /etc/xen/scripts/block-drbd failed; error detected. backend/vbd/6= /51712/hotplug-status error to xenstore. > > root: /etc/xen/scripts/block-drbd: /etc/xen/scripts/block-drbd failed= ; error detected. > >=20 > > Signed-off-by: Valentin Vidic > > Cc: stable@vger.kernel.org > > --- > > drivers/block/xen-blkback/xenbus.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > >=20 > > diff --git a/drivers/block/xen-blkback/xenbus.c b/drivers/block/xen-b= lkback/xenbus.c > > index a4bc74e72c39..43bddc996709 100644 > > --- a/drivers/block/xen-blkback/xenbus.c > > +++ b/drivers/block/xen-blkback/xenbus.c > > @@ -323,6 +323,7 @@ static void xen_blkif_free(struct xen_blkif *blki= f) > > { > > WARN_ON(xen_blkif_disconnect(blkif)); > > xen_vbd_free(&blkif->vbd); > > + xenbus_switch_state(blkif->be->dev, XenbusStateClosed); > > kfree(blkif->be->mode); > > kfree(blkif->be); > > =20 > > @@ -814,7 +815,6 @@ static void frontend_changed(struct xenbus_device= *dev, > > =20 > > case XenbusStateClosed: > > xen_blkif_disconnect(be->blkif); > > - xenbus_switch_state(dev, XenbusStateClosed); > > if (xenbus_dev_is_online(dev)) > > break; >=20 > AFAICT, this will cause the backend to never switch to 'Closed' state > until the toolstack sets online to 0, which is not good IMO. >=20 > If for example a frontend decides to close a device, the backend will > stay in state 'Closing' until the toolstack actually removes the disk > by setting online to 0. >=20 > This will prevent resetting blk connections, as blkback will refuse to > switch to state XenbusStateInitWait unless it's at XenbusStateClosed > (see the XenbusStateInitialising case in frontend_changed), which will > never be reached with your patch. Ok, is it possible to test this somehow? > Maybe the easiest solution would be to wait in the block-drbd script > until the device is released? Maybe using fstat in a loop or one of > the drbd tools? That is an option, but I don't know if it is possible to check device release like that. Including drbd-user in CC, maybe they have some idea how to solve this. --=20 Valentin From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED,USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2D655C43334 for ; Wed, 5 Sep 2018 16:28:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C044C206BA for ; Wed, 5 Sep 2018 16:28:05 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org C044C206BA Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=CARNet.hr Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727635AbeIEU67 convert rfc822-to-8bit (ORCPT ); Wed, 5 Sep 2018 16:58:59 -0400 Received: from mail.CARNet.hr ([161.53.123.6]:45259 "EHLO mail.carnet.hr" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726189AbeIEU67 (ORCPT ); Wed, 5 Sep 2018 16:58:59 -0400 Received: from cnzgrivvl-t440p.carpriv.carnet.hr ([161.53.12.131]:56478 helo=gavran.carpriv.carnet.hr) by mail.carnet.hr with smtp (Exim 4.80) (envelope-from ) id 1fxaeq-0004ym-Cr; Wed, 05 Sep 2018 18:27:57 +0200 Received: by gavran.carpriv.carnet.hr (Postfix, from userid 1000) id 4F09B2012E; Wed, 5 Sep 2018 18:27:56 +0200 (CEST) Date: Wed, 5 Sep 2018 18:27:56 +0200 From: Valentin Vidic To: Roger Pau =?iso-8859-1?Q?Monn=E9?= Cc: Konrad Rzeszutek Wilk , Jens Axboe , xen-devel@lists.xenproject.org, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org, drbd-user@lists.linbit.com Message-ID: <20180905162756.GA26705@gavran.carpriv.carnet.hr> References: <20180829065214.23546-1-Valentin.Vidic@CARNet.hr> <20180905103649.edugijsjx4v2fbxd@mac.bytemobile.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline In-Reply-To: <20180905103649.edugijsjx4v2fbxd@mac.bytemobile.com> User-Agent: Mutt/1.10.1 (2018-07-13) Content-Transfer-Encoding: 8BIT X-SA-Exim-Connect-IP: 161.53.12.131 Subject: Re: [PATCH] xen-blkback: Switch to closed state after releasing the backing device X-SA-Exim-Version: 4.2.1 (built Mon, 26 Dec 2011 16:24:06 +0000) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Sep 05, 2018 at 12:36:49PM +0200, Roger Pau Monné wrote: > On Wed, Aug 29, 2018 at 08:52:14AM +0200, Valentin Vidic wrote: > > Switching to closed state earlier can cause the block-drbd > > script to fail with 'Device is held open by someone': > > > > root: /etc/xen/scripts/block-drbd: remove XENBUS_PATH=backend/vbd/6/51712 > > kernel: [ 2222.278235] block drbd6: State change failed: Device is held open by someone > > kernel: [ 2222.278304] block drbd6: state = { cs:Connected ro:Primary/Secondary ds:UpToDate/UpToDate r----- } > > kernel: [ 2222.278340] block drbd6: wanted = { cs:Connected ro:Secondary/Secondary ds:UpToDate/UpToDate r----- } > > root: /etc/xen/scripts/block-drbd: Writing backend/vbd/6/51712/hotplug-error /etc/xen/scripts/block-drbd failed; error detected. backend/vbd/6/51712/hotplug-status error to xenstore. > > root: /etc/xen/scripts/block-drbd: /etc/xen/scripts/block-drbd failed; error detected. > > > > Signed-off-by: Valentin Vidic > > Cc: stable@vger.kernel.org > > --- > > drivers/block/xen-blkback/xenbus.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/drivers/block/xen-blkback/xenbus.c b/drivers/block/xen-blkback/xenbus.c > > index a4bc74e72c39..43bddc996709 100644 > > --- a/drivers/block/xen-blkback/xenbus.c > > +++ b/drivers/block/xen-blkback/xenbus.c > > @@ -323,6 +323,7 @@ static void xen_blkif_free(struct xen_blkif *blkif) > > { > > WARN_ON(xen_blkif_disconnect(blkif)); > > xen_vbd_free(&blkif->vbd); > > + xenbus_switch_state(blkif->be->dev, XenbusStateClosed); > > kfree(blkif->be->mode); > > kfree(blkif->be); > > > > @@ -814,7 +815,6 @@ static void frontend_changed(struct xenbus_device *dev, > > > > case XenbusStateClosed: > > xen_blkif_disconnect(be->blkif); > > - xenbus_switch_state(dev, XenbusStateClosed); > > if (xenbus_dev_is_online(dev)) > > break; > > AFAICT, this will cause the backend to never switch to 'Closed' state > until the toolstack sets online to 0, which is not good IMO. > > If for example a frontend decides to close a device, the backend will > stay in state 'Closing' until the toolstack actually removes the disk > by setting online to 0. > > This will prevent resetting blk connections, as blkback will refuse to > switch to state XenbusStateInitWait unless it's at XenbusStateClosed > (see the XenbusStateInitialising case in frontend_changed), which will > never be reached with your patch. Ok, is it possible to test this somehow? > Maybe the easiest solution would be to wait in the block-drbd script > until the device is released? Maybe using fstat in a loop or one of > the drbd tools? That is an option, but I don't know if it is possible to check device release like that. Including drbd-user in CC, maybe they have some idea how to solve this. -- Valentin From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.CARNet.hr ([161.53.123.6]:45259 "EHLO mail.carnet.hr" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726189AbeIEU67 (ORCPT ); Wed, 5 Sep 2018 16:58:59 -0400 Date: Wed, 5 Sep 2018 18:27:56 +0200 From: Valentin Vidic To: Roger Pau =?iso-8859-1?Q?Monn=E9?= Cc: Konrad Rzeszutek Wilk , Jens Axboe , xen-devel@lists.xenproject.org, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org, drbd-user@lists.linbit.com Message-ID: <20180905162756.GA26705@gavran.carpriv.carnet.hr> References: <20180829065214.23546-1-Valentin.Vidic@CARNet.hr> <20180905103649.edugijsjx4v2fbxd@mac.bytemobile.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline In-Reply-To: <20180905103649.edugijsjx4v2fbxd@mac.bytemobile.com> Content-Transfer-Encoding: 8BIT Subject: Re: [PATCH] xen-blkback: Switch to closed state after releasing the backing device Sender: stable-owner@vger.kernel.org List-ID: On Wed, Sep 05, 2018 at 12:36:49PM +0200, Roger Pau Monn� wrote: > On Wed, Aug 29, 2018 at 08:52:14AM +0200, Valentin Vidic wrote: > > Switching to closed state earlier can cause the block-drbd > > script to fail with 'Device is held open by someone': > > > > root: /etc/xen/scripts/block-drbd: remove XENBUS_PATH=backend/vbd/6/51712 > > kernel: [ 2222.278235] block drbd6: State change failed: Device is held open by someone > > kernel: [ 2222.278304] block drbd6: state = { cs:Connected ro:Primary/Secondary ds:UpToDate/UpToDate r----- } > > kernel: [ 2222.278340] block drbd6: wanted = { cs:Connected ro:Secondary/Secondary ds:UpToDate/UpToDate r----- } > > root: /etc/xen/scripts/block-drbd: Writing backend/vbd/6/51712/hotplug-error /etc/xen/scripts/block-drbd failed; error detected. backend/vbd/6/51712/hotplug-status error to xenstore. > > root: /etc/xen/scripts/block-drbd: /etc/xen/scripts/block-drbd failed; error detected. > > > > Signed-off-by: Valentin Vidic > > Cc: stable@vger.kernel.org > > --- > > drivers/block/xen-blkback/xenbus.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/drivers/block/xen-blkback/xenbus.c b/drivers/block/xen-blkback/xenbus.c > > index a4bc74e72c39..43bddc996709 100644 > > --- a/drivers/block/xen-blkback/xenbus.c > > +++ b/drivers/block/xen-blkback/xenbus.c > > @@ -323,6 +323,7 @@ static void xen_blkif_free(struct xen_blkif *blkif) > > { > > WARN_ON(xen_blkif_disconnect(blkif)); > > xen_vbd_free(&blkif->vbd); > > + xenbus_switch_state(blkif->be->dev, XenbusStateClosed); > > kfree(blkif->be->mode); > > kfree(blkif->be); > > > > @@ -814,7 +815,6 @@ static void frontend_changed(struct xenbus_device *dev, > > > > case XenbusStateClosed: > > xen_blkif_disconnect(be->blkif); > > - xenbus_switch_state(dev, XenbusStateClosed); > > if (xenbus_dev_is_online(dev)) > > break; > > AFAICT, this will cause the backend to never switch to 'Closed' state > until the toolstack sets online to 0, which is not good IMO. > > If for example a frontend decides to close a device, the backend will > stay in state 'Closing' until the toolstack actually removes the disk > by setting online to 0. > > This will prevent resetting blk connections, as blkback will refuse to > switch to state XenbusStateInitWait unless it's at XenbusStateClosed > (see the XenbusStateInitialising case in frontend_changed), which will > never be reached with your patch. Ok, is it possible to test this somehow? > Maybe the easiest solution would be to wait in the block-drbd script > until the device is released? Maybe using fstat in a loop or one of > the drbd tools? That is an option, but I don't know if it is possible to check device release like that. Including drbd-user in CC, maybe they have some idea how to solve this. -- Valentin