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Re: [Qemu-devel] [PATCH 1/7] block: only force IO completion in .bdrv_tr
From: |
Peter Lieven |
Subject: |
Re: [Qemu-devel] [PATCH 1/7] block: only force IO completion in .bdrv_truncate if we are shrinking |
Date: |
Wed, 06 Mar 2013 20:03:32 +0100 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:15.0) Gecko/20120827 Thunderbird/15.0 |
Am 06.03.2013 19:48, schrieb Jeff Cody:
> On Wed, Mar 06, 2013 at 07:31:51PM +0100, Paolo Bonzini wrote:
>> Il 06/03/2013 19:14, Jeff Cody ha scritto:
>>> QCOW breaks with it using a normal raw posix file as a device. As a
>>> test: qemu-img create -f qcow test.qcow 5G. Now run qemu with that
>>> drive mounted, and try to partition and format it. QEMU now asserts.
>>>
>>> The nicety of being able to using truncate during a write call,
>>> especially for VHDX (which can have relatively large block/cluster
>>> sizes), so to grow the file sparsely in a dynamically allocated file.
>>
>> Perhaps we need two APIs, "truncate" and "revalidate".
>>
>> Truncate should be a no-op if (!bs->growable).
>>
>> Revalidate could be called by the block_resize monitor command with no
>> size specified.
>>
>> Paolo
>
> I think that is a good solution. Is it better to have "truncate" and
> "revalidate", or "truncate" and "grow", with grow being a subset of
> truncate, with fewer restrictions? There may still be operations
> where it is OK to grow a file, but not OK to shrink it.
>
Or as a first step:
a) Call brdv_drain_all() only if the device is shrinked (independently of
!bs->growable)
b) Call brdv_drain_all() inside iscsi_truncate() because it is a special
requirement there
c) Fix the value of bs->growable for all drivers
Peter
- [Qemu-devel] [PATCH 0/7] Initial VHDX support (and a bug fix for QCOW), Jeff Cody, 2013/03/06
- [Qemu-devel] [PATCH 1/7] block: only force IO completion in .bdrv_truncate if we are shrinking, Jeff Cody, 2013/03/06
- Re: [Qemu-devel] [PATCH 1/7] block: only force IO completion in .bdrv_truncate if we are shrinking, Peter Lieven, 2013/03/06
- Re: [Qemu-devel] [PATCH 1/7] block: only force IO completion in .bdrv_truncate if we are shrinking, Paolo Bonzini, 2013/03/06
- Re: [Qemu-devel] [PATCH 1/7] block: only force IO completion in .bdrv_truncate if we are shrinking, Jeff Cody, 2013/03/06
- Re: [Qemu-devel] [PATCH 1/7] block: only force IO completion in .bdrv_truncate if we are shrinking, Paolo Bonzini, 2013/03/06
- Re: [Qemu-devel] [PATCH 1/7] block: only force IO completion in .bdrv_truncate if we are shrinking, Jeff Cody, 2013/03/06
- Re: [Qemu-devel] [PATCH 1/7] block: only force IO completion in .bdrv_truncate if we are shrinking,
Peter Lieven <=
- Re: [Qemu-devel] [PATCH 1/7] block: only force IO completion in .bdrv_truncate if we are shrinking, Paolo Bonzini, 2013/03/06
- Re: [Qemu-devel] [PATCH 1/7] block: only force IO completion in .bdrv_truncate if we are shrinking, Kevin Wolf, 2013/03/07
- Re: [Qemu-devel] [PATCH 1/7] block: only force IO completion in .bdrv_truncate if we are shrinking, Peter Lieven, 2013/03/07
- Re: [Qemu-devel] [PATCH 1/7] block: only force IO completion in .bdrv_truncate if we are shrinking, Kevin Wolf, 2013/03/07
- Re: [Qemu-devel] [PATCH 1/7] block: only force IO completion in .bdrv_truncate if we are shrinking, Peter Lieven, 2013/03/07
- Re: [Qemu-devel] [PATCH 1/7] block: only force IO completion in .bdrv_truncate if we are shrinking, Kevin Wolf, 2013/03/07
- Re: [Qemu-devel] [PATCH 1/7] block: only force IO completion in .bdrv_truncate if we are shrinking, Peter Lieven, 2013/03/07
- Re: [Qemu-devel] [PATCH 1/7] block: only force IO completion in .bdrv_truncate if we are shrinking, Kevin Wolf, 2013/03/07
- Re: [Qemu-devel] [PATCH 1/7] block: only force IO completion in .bdrv_truncate if we are shrinking, Peter Lieven, 2013/03/07
- Re: [Qemu-devel] [PATCH 1/7] block: only force IO completion in .bdrv_truncate if we are shrinking, Paolo Bonzini, 2013/03/07