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Re: [Qemu-devel] [PATCH] Further tidy-up on block status
From: |
Alex Bligh |
Subject: |
Re: [Qemu-devel] [PATCH] Further tidy-up on block status |
Date: |
Wed, 14 Dec 2016 17:36:51 +0000 |
> On 14 Dec 2016, at 17:05, Vladimir Sementsov-Ogievskiy <address@hidden> wrote:
>>
>> However, this raises another question. Wouter deliberately made the
>> query format freeform so that you could e.g. set a context like:
>>
>> backup:modtime>201612081034
>>
>> which might (in theory) return a list of blocks which are newer than
>> the given timestamp. It would clearly be impossible to return all such
>> contexts. I wonder if we should carve out an exception here.
>>
>>
>
> Interesting. Even query 'backup:modtime>*' would be a problem, not only empty
> query list.
>
> Actually, we do not need to 'list contexts', as it is about management, not
> about data transfer. We only need a way to check, that particular query
> selects all needed contexts and no others. Just to be sure that we are know,
> what we will select by NBD_OPT_SET_META_CONTEXT with _same_ query.
>
> So, I suggest just to say, that _LIST_ can return error if too much contexts
> are selected. And same should be done for _SET_. And it should be documented
> that this result of query (list or error) should be equal for these two
> commands.
(two CCs that always bounce removed)
Hmmm... Well in the '*' case, it's up to the namespace as to how it parses
things, so '*' could be prohibited entirely or mean 'return the first 20
matching' or similar. So that's less of a problem. And 'set all' doesn't exist
(unlike 'list all').
I think in the LIST case we should allow the server to omit contexts under
certain circumstances, and allow SET to return ETOOBIG.
--
Alex Bligh
- [Qemu-devel] [PATCH] Further tidy-up on block status, Alex Bligh, 2016/12/14
- Re: [Qemu-devel] [PATCH] Further tidy-up on block status, Vladimir Sementsov-Ogievskiy, 2016/12/14
- Re: [Qemu-devel] [PATCH] Further tidy-up on block status, Alex Bligh, 2016/12/14
- Re: [Qemu-devel] [PATCH] Further tidy-up on block status, Vladimir Sementsov-Ogievskiy, 2016/12/14
- Re: [Qemu-devel] [PATCH] Further tidy-up on block status,
Alex Bligh <=
- Re: [Qemu-devel] [PATCH] Further tidy-up on block status, Vladimir Sementsov-Ogievskiy, 2016/12/14
- Re: [Qemu-devel] [Nbd] [PATCH] Further tidy-up on block status, Wouter Verhelst, 2016/12/14
- Re: [Qemu-devel] [Nbd] [PATCH] Further tidy-up on block status, Alex Bligh, 2016/12/14
- Re: [Qemu-devel] [Nbd] [PATCH] Further tidy-up on block status, Wouter Verhelst, 2016/12/14
- Re: [Qemu-devel] [Nbd] [PATCH] Further tidy-up on block status, Alex Bligh, 2016/12/14
- Re: [Qemu-devel] [Nbd] [PATCH] Further tidy-up on block status, Wouter Verhelst, 2016/12/14
- Re: [Qemu-devel] [Nbd] [PATCH] Further tidy-up on block status, Vladimir Sementsov-Ogievskiy, 2016/12/26
- Re: [Qemu-devel] [Nbd] [PATCH] Further tidy-up on block status, Alex Bligh, 2016/12/29
- Re: [Qemu-devel] [Nbd] [PATCH] Further tidy-up on block status, Vladimir Sementsov-Ogievskiy, 2016/12/29
- Re: [Qemu-devel] [Nbd] [PATCH] Further tidy-up on block status, Alex Bligh, 2016/12/14