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Re: [Qemu-devel] [PATCH v13 00/14] Drop in_use from BlockDriverState and
From: |
Richard W.M. Jones |
Subject: |
Re: [Qemu-devel] [PATCH v13 00/14] Drop in_use from BlockDriverState and enable point-in-time snapshot exporting over NBD |
Date: |
Wed, 12 Feb 2014 18:27:49 +0000 |
User-agent: |
Mutt/1.5.20 (2009-12-10) |
On Wed, Feb 12, 2014 at 09:22:29AM -0800, Ian Main wrote:
> On Wed, Jan 29, 2014 at 01:07:27PM +0800, Fam Zheng wrote:
> > This series adds for point-in-time snapshot NBD exporting based on
> > blockdev-backup (variant of drive-backup with existing device as target).
> >
> > We get a thin point-in-time snapshot by COW mechanism of drive-backup, and
> > export it through built in NBD server. The steps are as below:
> >
> > 1. (SHELL) qemu-img create -f qcow2 BACKUP.qcow2 <source size here>
> >
> > (Alternatively we can use -o backing_file=RUNNING-VM.img to omit
> > explicitly
> > providing the size by ourselves, but it's risky because
> > RUNNING-VM.qcow2 is
> > used r/w by guest. Whether or not setting backing file in the image file
> > doesn't matter, as we are going to override the backing hd in the next
> > step)
> >
> > 2. (QMP) blockdev-add backing=source-drive file.driver=file
> > file.filename=BACKUP.qcow2 id=target0 if=none driver=qcow2
> >
> > (where source-drive is the running BlockDriverState name for
> > RUNNING-VM.img. This patch implements "backing=" option to override
> > backing_hd for added drive)
> >
> > 3. (QMP) blockdev-backup device=source-drive sync=none target=target0
> >
> > (this is the QMP command introduced by this series, which use a named
> > device as target of drive-backup)
> >
> > 4. (QMP) nbd-server-add device=target0
> >
> > When image fleecing done:
> >
> > 1. (QMP) block-job-cancel device=source-drive
> >
> > 2. (HMP) drive_del target0
> >
> > 3. (SHELL) rm BACKUP.qcow2
> >
> > v12 -> v13: Address comments from Stefan.
> >
> > [05/15] block: Add bdrv_set_backing_hd()
> > Remove duplicated assignments.
> >
> > [10/15] qmp: Add command 'blockdev-backup'
> > Add check for source == target.
> >
> > [13/15] block: Add blockdev-backup to transaction
> > New.
> >
> > [14/15] qemu-iotests: Test blockdev-backup in 055
> > New.
> >
> > [15/15] qemu-iotests: Image fleecing test case 081
> > New. Hope this number has no conflict. I have a 080 on my
> > iothrottling test branch.
> >
> > v11 -> v12: Rebase to qemu.git.
> > Call bdrv_refresh_limits() in bdrv_set_backing_hd().
>
> I've been using this patch and testing it for the last few weeks and it
> all seems to be working very well. Kevin is waiting on more reviewers for
> this rev before it can go in. Can someone else look through this please?
>
> Tested-by: Ian Main <address@hidden>
Adding Pino Toscano to this thread, since he is working on libguestfs.
Pino, I believe the latest patch series is this:
https://lists.gnu.org/archive/html/qemu-devel/2014-01/threads.html#03904
Rich.
> > Fam Zheng (14):
> > block: Add BlockOpType enum
> > block: Introduce op_blockers to BlockDriverState
> > block: Replace in_use with operation blocker
> > block: Move op_blocker check from block_job_create to its caller
> > block: Add bdrv_set_backing_hd()
> > block: Add backing_blocker in BlockDriverState
> > block: Parse "backing" option to reference existing BDS
> > block: Support dropping active in bdrv_drop_intermediate
> > stream: Use bdrv_drop_intermediate and drop close_unused_images
> > qmp: Add command 'blockdev-backup'
> > block: Allow backup on referenced named BlockDriverState
> > block: Add blockdev-backup to transaction
> > qemu-iotests: Test blockdev-backup in 055
> > qemu-iotests: Image fleecing test case 081
> >
> > block-migration.c | 7 +-
> > block.c | 306
> > ++++++++++++++++++++++++++--------------
> > block/backup.c | 26 ++++
> > block/commit.c | 1 +
> > block/stream.c | 30 +---
> > blockdev.c | 118 ++++++++++++++--
> > blockjob.c | 14 +-
> > hw/block/dataplane/virtio-blk.c | 19 ++-
> > include/block/block.h | 29 +++-
> > include/block/block_int.h | 9 +-
> > include/block/blockjob.h | 3 +
> > qapi-schema.json | 50 +++++++
> > qmp-commands.hx | 44 ++++++
> > tests/qemu-iotests/055 | 275 ++++++++++++++++++++++++++++++------
> > tests/qemu-iotests/055.out | 4 +-
> > tests/qemu-iotests/081 | 99 +++++++++++++
> > tests/qemu-iotests/081.out | 5 +
> > tests/qemu-iotests/group | 1 +
> > 18 files changed, 836 insertions(+), 204 deletions(-)
> > create mode 100755 tests/qemu-iotests/081
> > create mode 100644 tests/qemu-iotests/081.out
> >
> > --
> > 1.8.5.3
> >
--
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
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