From: Eric Blake <eblake@redhat.com>
To: Anton Nefedov <anton.nefedov@virtuozzo.com>, qemu-devel@nongnu.org
Cc: kwolf@redhat.com, "Denis V. Lunev" <den@openvz.org>,
den@virtuozzo.com, mreitz@redhat.com
Subject: Re: [Qemu-devel] [PATCH v1 04/13] qcow2: preallocation at image expand
Date: Mon, 22 May 2017 14:29:53 -0500 [thread overview]
Message-ID: <b2e896f2-363b-9ce0-9ae3-d814c2d503fd@redhat.com> (raw)
In-Reply-To: <1495186480-114192-5-git-send-email-anton.nefedov@virtuozzo.com>
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On 05/19/2017 04:34 AM, Anton Nefedov wrote:
> From: "Denis V. Lunev" <den@openvz.org>
>
> This patch adds image preallocation at expand to provide better locality
> of QCOW2 image file and optimize this procedure for some distributed
> storages where this procedure is slow.
>
> Image expand requests have to be suspended until the allocation is
> performed which is done via special QCowL2Meta.
> This meta is invisible to handle_dependencies() code.
> This is the main reason for also calling preallocation before metadata
> write: it might intersect with preallocation triggered by another IO,
> and has to yield
How does this interact with Max's work on preallocated truncate?
https://lists.gnu.org/archive/html/qemu-devel/2017-04/msg00267.html
--
Eric Blake, Principal Software Engineer
Red Hat, Inc. +1-919-301-3266
Virtualization: qemu.org | libvirt.org
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next prev parent reply other threads:[~2017-05-22 19:30 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-05-19 9:34 [Qemu-devel] [PATCH v1 00/13] qcow2: space preallocation and COW improvements Anton Nefedov
2017-05-19 9:34 ` [Qemu-devel] [PATCH v1 01/13] qcow2: alloc space for COW in one chunk Anton Nefedov
2017-05-22 19:00 ` Eric Blake
2017-05-23 8:28 ` Anton Nefedov
2017-05-23 9:13 ` Denis V. Lunev
2017-05-26 8:11 ` Kevin Wolf
2017-05-26 8:57 ` Denis V. Lunev
2017-05-26 10:09 ` Anton Nefedov
2017-05-26 11:16 ` Kevin Wolf
2017-05-26 10:57 ` Denis V. Lunev
2017-05-26 11:32 ` Kevin Wolf
2017-05-19 9:34 ` [Qemu-devel] [PATCH v1 02/13] qcow2: is_zero_sectors(): return true if area is outside of backing file Anton Nefedov
2017-05-22 19:12 ` Eric Blake
2017-05-22 19:14 ` Eric Blake
2017-05-23 8:35 ` Anton Nefedov
2017-05-19 9:34 ` [Qemu-devel] [PATCH v1 03/13] qcow2: do not COW the empty areas Anton Nefedov
2017-05-22 19:24 ` Eric Blake
2017-05-23 8:31 ` Anton Nefedov
2017-05-23 9:15 ` Denis V. Lunev
2017-05-19 9:34 ` [Qemu-devel] [PATCH v1 04/13] qcow2: preallocation at image expand Anton Nefedov
2017-05-22 19:29 ` Eric Blake [this message]
2017-05-24 16:57 ` Anton Nefedov
2017-05-19 9:34 ` [Qemu-devel] [PATCH v1 05/13] qcow2: set inactive flag Anton Nefedov
2017-05-26 8:11 ` Kevin Wolf
2017-05-31 16:56 ` Anton Nefedov
2017-05-19 9:34 ` [Qemu-devel] [PATCH v1 06/13] qcow2: truncate preallocated space Anton Nefedov
2017-05-19 9:34 ` [Qemu-devel] [PATCH v1 07/13] qcow2: check space leak at the end of the image Anton Nefedov
2017-05-19 9:34 ` [Qemu-devel] [PATCH v1 08/13] qcow2: handle_prealloc(): find out if area zeroed by earlier preallocation Anton Nefedov
2017-05-19 9:34 ` [Qemu-devel] [PATCH v1 09/13] qcow2: fix misleading comment about L2 linking Anton Nefedov
2017-05-19 9:34 ` [Qemu-devel] [PATCH v1 10/13] qcow2-cluster: slightly refactor handle_dependencies() Anton Nefedov
2017-05-19 9:34 ` [Qemu-devel] [PATCH v1 11/13] qcow2-cluster: make handle_dependencies() logic easier to follow Anton Nefedov
2017-05-22 19:37 ` Eric Blake
2017-05-19 9:34 ` [Qemu-devel] [PATCH v1 12/13] qcow2: allow concurrent unaligned writes to the same clusters Anton Nefedov
2017-05-19 9:34 ` [Qemu-devel] [PATCH v1 13/13] iotest 046: test simultaneous cluster write error case Anton Nefedov
2017-05-23 14:35 ` [Qemu-devel] [PATCH v1 00/13] qcow2: space preallocation and COW improvements Eric Blake
2017-05-23 14:51 ` Denis V. Lunev
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