Re: [Qemu-devel] [PATCH RFC 0/5] generic image locking and crash recovery

["Denis V. Lunev" <den@openvz.org>]

On 12/23/2015 11:09 AM, Fam Zheng wrote:
> On Wed, 12/23 10:46, Denis V. Lunev wrote:
>> This series of patches is aimed to prevent usage of image
>> file by different qemu instances. In case we are the first
>> instance, and option lock is lockfile, - we lock the image file,
>> and if check option is on, we check the file and fix it if
>> nessecary. If one of this two ops fails - the image is closed
>> with the error.
>>
>> Patchset is not polished at all! Sent for a discussion as an alternative
>> approach.
> I like this approach. The first two patches match what I was thinking of.
>
> Patch 5 is okay, the unclean flag reflects HEADER_INUSE_MAGIC in parallels
> header; unfortunately patch 4 is wrong because qcow2 lacks a counterpart flag
> in the format, and the patch only modified an in memory variable.  we have to
> add this as a compatible_features bit in order to support this operation.
yep :) this could be done, no problem.

> Didn't review very closely because at least one patch doesn't seem to compile.
> :)
>
> Fam
>
which compile error do you have?

I have double checked that it is compiled OK on

commit 5dc42c186d63b7b338594fc071cf290805dcc5a5
Merge: c595b21 7236975
Author: Peter Maydell <peter.maydell@linaro.org>
Date:   Tue Dec 22 14:21:42 2015 +0000

     Merge remote-tracking branch 
'remotes/stefanha/tags/block-pull-request' into staging

     # gpg: Signature made Tue 22 Dec 2015 08:52:55 GMT using RSA key ID 
81AB73C8
     # gpg: Good signature from "Stefan Hajnoczi <stefanha@redhat.com>"
     # gpg:                 aka "Stefan Hajnoczi <stefanha@gmail.com>"

     * remotes/stefanha/tags/block-pull-request:
       sdhci: add optional quirk property to disable card 
insertion/removal interrupts
       sdhci: don't raise a command index error for an unexpected response
       sd: sdhci: Delete over-zealous power check
       scripts/gdb: Fix a python exception in mtree.py
       parallels: add format spec
       block/mirror: replace IOV_MAX with blk_get_max_iov()
       block: replace IOV_MAX with BlockLimits.max_iov
       block-backend: add blk_get_max_iov()
       block: add BlockLimits.max_iov field
       virtio-blk: trivial code optimization

     Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

Den