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Re: [Qemu-block] [PATCH v15 18/21] block: Reuse bs as backing hd for dri
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From: |
Kevin Wolf |
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Subject: |
Re: [Qemu-block] [PATCH v15 18/21] block: Reuse bs as backing hd for drive-backup sync=none |
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Date: |
Wed, 26 Apr 2017 14:52:27 +0200 |
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User-agent: |
Mutt/1.5.21 (2010-09-15) |
Am 26.04.2017 um 05:34 hat Fam Zheng geschrieben:
> Signed-off-by: Fam Zheng <address@hidden>
The commit message is a bit terse. :-)
So I think this means that instead of opening the backing file of the
backup (which is probably the active file of the VM) a second time, we
instead take a reference on the existing node. Very good idea.
In fact, my question is: How did this ever work? Did we just neglect to
test this? The backup backing file will use stale qcow2 metadata when we
continue to write to the source.
Unless I'm missing something, I'd propose this for qemu-stable.
Also, mirror with MIRROR_OPEN_BACKING_CHAIN probably has a similar
problem with opening the images in the backing chain a second time.
Kevin
- [Qemu-block] [PATCH v15 13/21] iotests: 091: Quit QEMU before checking image, (continued)
- [Qemu-block] [PATCH v15 13/21] iotests: 091: Quit QEMU before checking image, Fam Zheng, 2017/04/25
- [Qemu-block] [PATCH v15 14/21] iotests: 172: Use separate images for multiple devices, Fam Zheng, 2017/04/25
- [Qemu-block] [PATCH v15 15/21] tests: Use null-co:// instead of /dev/null as the dummy image, Fam Zheng, 2017/04/25
- [Qemu-block] [PATCH v15 16/21] file-posix: Add 'locking' option, Fam Zheng, 2017/04/25
- [Qemu-block] [PATCH v15 17/21] tests: Disable image lock in test-replication, Fam Zheng, 2017/04/25
- [Qemu-block] [PATCH v15 18/21] block: Reuse bs as backing hd for drive-backup sync=none, Fam Zheng, 2017/04/25
- Re: [Qemu-block] [PATCH v15 18/21] block: Reuse bs as backing hd for drive-backup sync=none,
Kevin Wolf <=
[Qemu-block] [PATCH v15 19/21] osdep: Add qemu_lock_fd and qemu_unlock_fd, Fam Zheng, 2017/04/25
[Qemu-block] [PATCH v15 20/21] file-posix: Add image locking to perm operations, Fam Zheng, 2017/04/25