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Re: [Qemu-block] [PATCH v12 02/10] block: Update comments on BDRV_BLOCK_
From: |
Eric Blake |
Subject: |
Re: [Qemu-block] [PATCH v12 02/10] block: Update comments on BDRV_BLOCK_* meanings |
Date: |
Fri, 5 May 2017 15:13:04 -0500 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.0 |
On 05/05/2017 03:06 PM, Max Reitz wrote:
> On 04.05.2017 05:07, Eric Blake wrote:
>> We had some conflicting documentation: a nice 8-way table that
>> described all possible combinations of DATA, ZERO, and
>> OFFSET_VALID, contrasted with text that implied that OFFSET_VALID
>> always meant raw data could be read directly. Furthermore, the
>> text refers a lot to bs->file, even though the interface was
>> updated back in 67a0fd2a to let the driver pass back which BDS (not
>> necessarily bs->file).
>
> Not sure about my English skills here, but is this missing a verb? ("to
> pass back which BDS...")
maybe s/which/a specific/
>
>> As the 8-way table is the intended
>> semantics, simplify the rest of the text to get rid of the
>> confusion.
>>
>> ALLOCATED is always set by the block layer for convenience (drivers
>> do not have to worry about it). RAW is used only internally, but
>
> Just one space after the period? How inconsistent! :-)
But do commit messages really count? :)
>> + * Internal flag:
>> + * BDRV_BLOCK_RAW: used internally to indicate that the request was
>> + * answered by a passthrough driver such as raw and that the
>
> s/passthrough/filter/? But I'm not even sure myself. Well, "passthrough"
> is a safe bet, so let's just go with it.
Calling 'raw' a filter driver is a bit weird - but in one sense, it is a
no-op filter (filter the protocol layer into the format layer by doing
nothing). Meanwhile 'commit' certainly sounds like more of a filter
than a passthrough. I could go either way, and filter is slightly
shorter. If there's a real reason to respin the series, 'filter' seems
reasonable if we're worried about line length, otherwise I'm just as
inclined to leave it alone.
>
> With the commit message fixed or a “no it's fine”:
>
> Reviewed-by: Max Reitz <address@hidden>
>
--
Eric Blake, Principal Software Engineer
Red Hat, Inc. +1-919-301-3266
Virtualization: qemu.org | libvirt.org
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- [Qemu-block] [PATCH v12 00/10] qcow2 zero-cluster tweaks [was add blkdebug tests], Eric Blake, 2017/05/03
- [Qemu-block] [PATCH v12 01/10] qcow2: Use consistent switch indentation, Eric Blake, 2017/05/03
- [Qemu-block] [PATCH v12 05/10] qcow2: Optimize zero_single_l2() to minimize L2 churn, Eric Blake, 2017/05/03
- [Qemu-block] [PATCH v12 04/10] qcow2: Make distinction between zero cluster types obvious, Eric Blake, 2017/05/03
- [Qemu-block] [PATCH v12 07/10] iotests: Add test 179 to cover write zeroes with unmap, Eric Blake, 2017/05/03