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().
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
