From: Eric Blake <eblake@redhat.com>
To: Tomoki Sekiyama <tomoki.sekiyama@hds.com>
Cc: lcapitulino@redhat.com, seiji.aguchi@hds.com,
qemu-devel@nongnu.org, mdroth@linux.vnet.ibm.com
Subject: Re: [Qemu-devel] [PATCH] qemu-ga: execute fsfreeze-freeze in reverse order of mounts
Date: Tue, 01 Oct 2013 15:25:17 -0600 [thread overview]
Message-ID: <524B3DBD.8020108@redhat.com> (raw)
In-Reply-To: <20131001210953.23207.28945.stgit@localhost.localdomain>
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On 10/01/2013 03:09 PM, Tomoki Sekiyama wrote:
> Currently, fsfreeze-freeze may cause deadlock if a guest has loopback mounts
> of image files in its disk; e.g.:
>
> # mount | grep ^/
> /dev/vda1 / type ext4 (rw,noatime,seclabel,data=ordered)
> /tmp/disk.img on /mnt type ext4 (rw,relatime,seclabel)
>
> To avoid the deadlock, this freeze filesystems in reverse order of mounts.
s/freeze/freezes/
>
> Signed-off-by: Tomoki Sekiyama <tomoki.sekiyama@hds.com>
> ---
> qga/commands-posix.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
Thaw already worked in the forward direction; with your patch, this
means thaw undoes the actions by freeze in the opposite order (last
frozen is first thawed), which is also a good thing.
Reviewed-by: Eric Blake <eblake@redhat.com>
--
Eric Blake eblake redhat com +1-919-301-3266
Libvirt virtualization library http://libvirt.org
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next prev parent reply other threads:[~2013-10-01 21:25 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-10-01 21:09 [Qemu-devel] [PATCH] qemu-ga: execute fsfreeze-freeze in reverse order of mounts Tomoki Sekiyama
2013-10-01 21:25 ` Eric Blake [this message]
2013-10-08 20:49 ` Michael Roth
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