[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [PATCH v4 2/7] nbd: Add new qemu:allocation-depth metadata context
From: |
Eric Blake |
Subject: |
Re: [PATCH v4 2/7] nbd: Add new qemu:allocation-depth metadata context |
Date: |
Thu, 22 Oct 2020 16:45:21 -0500 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.3.1 |
On 10/14/20 6:52 AM, Vladimir Sementsov-Ogievskiy wrote:
>> docs/interop/nbd.txt | 27 ++++++++++---
>
> [..]
>
>> +In the allocation depth context, bits 0 and 1 form a tri-state value:
>> +
>> + bits 0-1: 00: NBD_STATE_DEPTH_UNALLOC, the extent is unallocated
>> + 01: NBD_STATE_DEPTH_LOCAL, the extent is allocated in the
>> + top level of the image
>
> Hmm. I always thought that "image" == file, so backing chain is a chain
> of images,
> not a several levels of one image. If it is so, than it should be "the
> top level image".
> And "levels of the image" may designate internal qcow2 snapshots
> unrelated here..
It's fuzzy. From the guest point of view, we are serving a single guest
image by use of multiple files in the host. I will do s/level/layer/,
to match the wording I already had on the next line:
> 10: NBD_STATE_DEPTH_BACKING, the extent is inherited from a
> backing layer
--
Eric Blake, Principal Software Engineer
Red Hat, Inc. +1-919-301-3226
Virtualization: qemu.org | libvirt.org
- [PATCH v4 0/7] Exposing backing-chain allocation over NBD, Eric Blake, 2020/10/09
- [PATCH v4 1/7] nbd: Utilize QAPI_CLONE for type conversion, Eric Blake, 2020/10/09
- [PATCH v4 2/7] nbd: Add new qemu:allocation-depth metadata context, Eric Blake, 2020/10/09
- [PATCH v4 6/7] nbd: Refactor counting of metadata contexts, Eric Blake, 2020/10/09
- [PATCH v4 3/7] nbd: Add 'qemu-nbd -A' to expose allocation depth, Eric Blake, 2020/10/09
- [PATCH v4 4/7] nbd: Update qapi to support exporting multiple bitmaps, Eric Blake, 2020/10/09
[PATCH v4 5/7] nbd: Simplify qemu bitmap context name, Eric Blake, 2020/10/09