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Re: [Qemu-devel] [PATCH 2/5] block/dirty-bitmaps: rename frozen predicat
From: |
John Snow |
Subject: |
Re: [Qemu-devel] [PATCH 2/5] block/dirty-bitmaps: rename frozen predicate helper |
Date: |
Tue, 12 Feb 2019 13:30:44 -0500 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.4.0 |
On 2/12/19 1:26 PM, Eric Blake wrote:
> On 2/11/19 7:02 PM, John Snow wrote:
>> "Frozen" was a good description a long time ago, but it isn't adequate now.
>> Rename the frozen predicate to has_successor to make the semantics of the
>> predicate more clear to outside callers.
>>
>> In the process, remove some calls to frozen() that no longer semantically
>> make sense. For enabled and disabled in particular, it's actually okay for
>> the internals to do this but only forbidden for users to invoke them, and
>> all of the QMP entry uses already check against qmp_locked.
>>
>> Several other assertions really want to check that the bitmap isn't in-use
>> by another operation -- use the qmp_locked function for this instead, which
>> presently also checks for has_successor.
>> ---
>
> Missing S-o-b on entire series, so you have to send v2 anyway :)
>
>> @@ -244,12 +244,16 @@ int
>> bdrv_dirty_bitmap_create_successor(BlockDriverState *bs,
>> uint64_t granularity;
>> BdrvDirtyBitmap *child;
>>
>> - if (bdrv_dirty_bitmap_frozen(bitmap)) {
>> - error_setg(errp, "Cannot create a successor for a bitmap that is "
>> - "currently frozen");
>> + if (bdrv_dirty_bitmap_has_successor(bitmap)) {
>> + error_setg(errp, "Cannot create a successor for a bitmap that
>> already "
>> + "has one");
>> + return -1;
>> + }
>> + if (bdrv_dirty_bitmap_user_locked(bitmap)) {
>> + error_setg(errp, "Cannot create a successor for a bitmap that is
>> in-use "
>> + "by an operation.");
>> return -1;
>
> No trailing dot in error_setg().
>
D'oh. I need to re-enable checkpatch, obviously.
> Should these two errors be swapped (check for locked before
> has_successor)? After all, having a successor is an internal detail,
> whereas being in use by something I already triggered is fairly
> straightforward to understand.
>
Good point. Will do.
>
>> @@ -325,7 +328,7 @@ BdrvDirtyBitmap
>> *bdrv_dirty_bitmap_abdicate(BlockDriverState *bs,
>> /**
>> * In cases of failure where we can no longer safely delete the parent,
>> * we may wish to re-join the parent and child/successor.
>> - * The merged parent will be un-frozen, but not explicitly re-enabled.
>> + * The merged parent will not be user_locked, but not explicitly re-enabled.
>
> s/but not/nor/
>
I was trying to draw a contrast between "We will forcibly set locked =
false, but make no guaranteed about enable/disable."
I guess nor still works in that case.
- [Qemu-devel] [PATCH 0/5] dirty-bitmaps: deprecate @status field, John Snow, 2019/02/11
- [Qemu-devel] [PATCH 1/5] block/dirty-bitmap: add recording and busy properties, John Snow, 2019/02/11
- [Qemu-devel] [PATCH 2/5] block/dirty-bitmaps: rename frozen predicate helper, John Snow, 2019/02/11
- [Qemu-devel] [PATCH 4/5] block/dirty-bitmap: explicitly lock bitmaps with successors, John Snow, 2019/02/11
- [Qemu-devel] [PATCH 3/5] block/dirty-bitmap: change semantics of enabled predicate, John Snow, 2019/02/11
- [Qemu-devel] [PATCH 5/5] block/dirty-bitmaps: unify qmp_locked and user_locked calls, John Snow, 2019/02/11
- Re: [Qemu-devel] [PATCH 0/5] dirty-bitmaps: deprecate @status field, Eric Blake, 2019/02/12