* [Qemu-devel] Reopen file descriptors on 'cont' command
@ 2015-02-26 0:32 Christopher Pereira
2015-03-06 17:19 ` Stefan Hajnoczi
0 siblings, 1 reply; 3+ messages in thread
From: Christopher Pereira @ 2015-02-26 0:32 UTC (permalink / raw)
To: qemu-devel
Hi,
Does qemu reopen files on a 'cont' command?
When working with images on a gluster volume, file descriptors may get
into a bad state because of network timeouts, remounting a share,
etc...and reinitializing file descriptors may be usefull to get paused
VMs up again.
Related BZ:
https://bugzilla.redhat.com/show_bug.cgi?id=1058300
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [Qemu-devel] Reopen file descriptors on 'cont' command
2015-02-26 0:32 [Qemu-devel] Reopen file descriptors on 'cont' command Christopher Pereira
@ 2015-03-06 17:19 ` Stefan Hajnoczi
2015-03-06 17:43 ` Christopher Pereira
0 siblings, 1 reply; 3+ messages in thread
From: Stefan Hajnoczi @ 2015-03-06 17:19 UTC (permalink / raw)
To: Christopher Pereira; +Cc: qemu-devel
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On Wed, Feb 25, 2015 at 09:32:18PM -0300, Christopher Pereira wrote:
> Does qemu reopen files on a 'cont' command?
>
> When working with images on a gluster volume, file descriptors may get into
> a bad state because of network timeouts, remounting a share, etc...and
> reinitializing file descriptors may be usefull to get paused VMs up again.
>
> Related BZ:
> https://bugzilla.redhat.com/show_bug.cgi?id=1058300
No, QEMU doesn't reopen file descriptors.
This can be challenging because QEMU supports file descriptor passing,
which is used when the QEMU process is isolated using SELinux so it
cannot open files itself. Reopening would require new file descriptors
passed in from the management tool.
Stefan
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^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [Qemu-devel] Reopen file descriptors on 'cont' command
2015-03-06 17:19 ` Stefan Hajnoczi
@ 2015-03-06 17:43 ` Christopher Pereira
0 siblings, 0 replies; 3+ messages in thread
From: Christopher Pereira @ 2015-03-06 17:43 UTC (permalink / raw)
To: Stefan Hajnoczi; +Cc: qemu-devel
On 06-03-2015 14:19, Stefan Hajnoczi wrote:
> On Wed, Feb 25, 2015 at 09:32:18PM -0300, Christopher Pereira wrote:
>> Does qemu reopen files on a 'cont' command?
>>
>> When working with images on a gluster volume, file descriptors may get into
>> a bad state because of network timeouts, remounting a share, etc...and
>> reinitializing file descriptors may be usefull to get paused VMs up again.
>>
>> Related BZ:
>> https://bugzilla.redhat.com/show_bug.cgi?id=1058300
> No, QEMU doesn't reopen file descriptors.
>
> This can be challenging because QEMU supports file descriptor passing,
> which is used when the QEMU process is isolated using SELinux so it
> cannot open files itself. Reopening would require new file descriptors
> passed in from the management tool.
Thanks Stefan.
I confirmed that libvirtd is not passing a FD to QEMU, but an image path.
Is QEMU reopening this image file when the VM is resumed?
QEMU must check if the FD (initialized by QEMU) is still valid,
especially after resuming a paused VM.
^ permalink raw reply [flat|nested] 3+ messages in thread
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2015-02-26 0:32 [Qemu-devel] Reopen file descriptors on 'cont' command Christopher Pereira
2015-03-06 17:19 ` Stefan Hajnoczi
2015-03-06 17:43 ` Christopher Pereira
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