Fam Zheng <f...@redhat.com> writes: > On 2013年11月28日 16:39, 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 ide0-hd0 is the running BlockDriverState name for >> RUNNING-VM.img. This patch implements "backing=" option to override >> backing_hd for added drive)
Are source-drive and ide0-hd0 the same thing? >> >> 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-complete device=ide0-hd0 >> >> 2. (HMP) drive_del target0 >> >> 3. (SHELL) rm BACKUP.qcow2 >> >> v6: Address Paolo's comments, (except for bitmask): >> - Add blocker for all backing_hd references, a relatively big change, >> some >> patches are reordered. >> - Introduce a few other necessary patches. >> - Move two snapshot checks into bdrv_snapshot_*. >> >> The interface is unchanged. >> > > Hi, > > Based on the size of change, this series needs some more review before > merging. And I'd like to know if there is any concern or objection > with op_blocker introduced here. I would like to base my next series > (incremental backup with dirty bitmap) on it. > > Any more reviews/comments? I started looking over it. First observation: needs a rebase :-}