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From: Anthony PERARD <anthony.perard@citrix.com>
To: Olaf Hering <olaf@aepfle.de>
Cc: xen-devel@lists.xenproject.org,
	"Ian Jackson" <ian.jackson@eu.citrix.com>,
	"Wei Liu" <wei.liu2@citrix.com>,
	"Roger Pau Monné" <roger.pau@citrix.com>
Subject: Re: [PATCH v1] libxl: fix migration of PV and PVH domUs with and without qemu
Date: Thu, 11 Apr 2019 16:56:02 +0100	[thread overview]
Message-ID: <20190411155602.GL1435@perard.uk.xensource.com> (raw)
In-Reply-To: <20190410103338.5456-1-olaf@aepfle.de>

On Wed, Apr 10, 2019 at 12:33:38PM +0200, Olaf Hering wrote:
> If a domU has a qemu-xen instance attached, it is required to call qemus
> "xen-save-devices-state" method. Without it, the receiving side of a PV or
> PVH migration may be unable to lock the image:
> 
> xen be: qdisk-51712: xen be: qdisk-51712: error: Failed to get "write" lock
> error: Failed to get "write" lock
> xen be: qdisk-51712: xen be: qdisk-51712: initialise() failed
> initialise() failed

I haven't managed to reproduce this, but this bug will go away with
QEMU 4.0. The backend in QEMU 4.0 will not lock the disk image anymore.

Maybe we could simply apply a patch to our qemu-xen trees which avoid
the lock on disk images for the pv disks? That would avoid a convoluted
patch to libxl.

The lock appeared in QEMU 2.10 (qemu-xen-4.10), and won't exist for pv
guest with QEMU 4.0 (qemu-xen-4.13).

-- 
Anthony PERARD

_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xenproject.org
https://lists.xenproject.org/mailman/listinfo/xen-devel

WARNING: multiple messages have this Message-ID (diff)
From: Anthony PERARD <anthony.perard@citrix.com>
To: Olaf Hering <olaf@aepfle.de>
Cc: xen-devel@lists.xenproject.org,
	"Ian Jackson" <ian.jackson@eu.citrix.com>,
	"Wei Liu" <wei.liu2@citrix.com>,
	"Roger Pau Monné" <roger.pau@citrix.com>
Subject: Re: [Xen-devel] [PATCH v1] libxl: fix migration of PV and PVH domUs with and without qemu
Date: Thu, 11 Apr 2019 16:56:02 +0100	[thread overview]
Message-ID: <20190411155602.GL1435@perard.uk.xensource.com> (raw)
Message-ID: <20190411155602.PiSWyinI-SQb81tTAW7VIZjL7OjHsJj5wDOgB3-xY_A@z> (raw)
In-Reply-To: <20190410103338.5456-1-olaf@aepfle.de>

On Wed, Apr 10, 2019 at 12:33:38PM +0200, Olaf Hering wrote:
> If a domU has a qemu-xen instance attached, it is required to call qemus
> "xen-save-devices-state" method. Without it, the receiving side of a PV or
> PVH migration may be unable to lock the image:
> 
> xen be: qdisk-51712: xen be: qdisk-51712: error: Failed to get "write" lock
> error: Failed to get "write" lock
> xen be: qdisk-51712: xen be: qdisk-51712: initialise() failed
> initialise() failed

I haven't managed to reproduce this, but this bug will go away with
QEMU 4.0. The backend in QEMU 4.0 will not lock the disk image anymore.

Maybe we could simply apply a patch to our qemu-xen trees which avoid
the lock on disk images for the pv disks? That would avoid a convoluted
patch to libxl.

The lock appeared in QEMU 2.10 (qemu-xen-4.10), and won't exist for pv
guest with QEMU 4.0 (qemu-xen-4.13).

-- 
Anthony PERARD

_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xenproject.org
https://lists.xenproject.org/mailman/listinfo/xen-devel

  parent reply	other threads:[~2019-04-11 15:57 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-04-10 10:33 [PATCH v1] libxl: fix migration of PV and PVH domUs with and without qemu Olaf Hering
2019-04-10 10:33 ` [Xen-devel] " Olaf Hering
2019-04-10 10:38 ` Olaf Hering
2019-04-10 10:38   ` [Xen-devel] " Olaf Hering
2019-04-10 15:08 ` Olaf Hering
2019-04-10 15:08   ` [Xen-devel] " Olaf Hering
2019-04-11 15:56 ` Anthony PERARD [this message]
2019-04-11 15:56   ` Anthony PERARD
2019-04-12  8:01   ` Olaf Hering
2019-04-12  8:01     ` [Xen-devel] " Olaf Hering

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