[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [Qemu-devel] [PATCH v2 1/9] block: Add COR filter driver
From: |
Max Reitz |
Subject: |
Re: [Qemu-devel] [PATCH v2 1/9] block: Add COR filter driver |
Date: |
Wed, 25 Apr 2018 13:18:03 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.7.0 |
On 2018-04-24 17:08, Alberto Garcia wrote:
> On Sat 21 Apr 2018 03:29:21 PM CEST, Max Reitz wrote:
>> This adds a simple copy-on-read filter driver. It relies on the already
>> existing COR functionality in the central block layer code, which may be
>> moved here once we no longer need it there.
>>
>> Signed-off-by: Max Reitz <address@hidden>
>
>
>> +#define PERM_PASSTHROUGH (BLK_PERM_CONSISTENT_READ \
>> + | BLK_PERM_WRITE \
>> + | BLK_PERM_RESIZE)
>> +#define PERM_UNCHANGED (BLK_PERM_ALL & ~PERM_PASSTHROUGH)
>> +
>> +static void cor_child_perm(BlockDriverState *bs, BdrvChild *c,
>> + const BdrvChildRole *role,
>> + BlockReopenQueue *reopen_queue,
>> + uint64_t perm, uint64_t shared,
>> + uint64_t *nperm, uint64_t *nshared)
>> +{
>> + if (c == NULL) {
>> + *nperm = (perm & PERM_PASSTHROUGH) | BLK_PERM_WRITE_UNCHANGED;
>> + *nshared = (shared & PERM_PASSTHROUGH) | PERM_UNCHANGED;
>> + return;
>> + }
>> +
>> + *nperm = (perm & PERM_PASSTHROUGH) |
>> + (c->perm & PERM_UNCHANGED);
>
> I admit I'm not completely familiar with this, but don't you need to add
> BLK_PERM_WRITE_UNCHANGED to *nperm ?
As long as it's requested in when the child is attached (which it is in
the "c == NULL" case), it should be part of c->perm then.
(And since PERM_PASSTHROUGH does not contain WRITE_UNCHANGED, it is part
of PERM_UNCHANGED.)
Max
>> + *nshared = (shared & PERM_PASSTHROUGH) |
>> + (c->shared_perm & PERM_UNCHANGED);
>> +}
>
> Berto
>
signature.asc
Description: OpenPGP digital signature
- [Qemu-devel] [PATCH v2 0/9] block: Add COR filter driver, Max Reitz, 2018/04/21
- [Qemu-devel] [PATCH v2 3/9] block: Add BDRV_REQ_WRITE_UNCHANGED flag, Max Reitz, 2018/04/21
- Re: [Qemu-devel] [PATCH v2 3/9] block: Add BDRV_REQ_WRITE_UNCHANGED flag, Eric Blake, 2018/04/25
- Re: [Qemu-devel] [PATCH v2 3/9] block: Add BDRV_REQ_WRITE_UNCHANGED flag, Max Reitz, 2018/04/25
- Re: [Qemu-devel] [PATCH v2 3/9] block: Add BDRV_REQ_WRITE_UNCHANGED flag, Eric Blake, 2018/04/25
- Re: [Qemu-devel] [PATCH v2 3/9] block: Add BDRV_REQ_WRITE_UNCHANGED flag, Kevin Wolf, 2018/04/26
- Re: [Qemu-devel] [PATCH v2 3/9] block: Add BDRV_REQ_WRITE_UNCHANGED flag, Max Reitz, 2018/04/28
- Re: [Qemu-devel] [PATCH v2 3/9] block: Add BDRV_REQ_WRITE_UNCHANGED flag, Kevin Wolf, 2018/04/30
[Qemu-devel] [PATCH v2 4/9] block: Set BDRV_REQ_WRITE_UNCHANGED for COR writes, Max Reitz, 2018/04/21
[Qemu-devel] [PATCH v2 6/9] block: Support BDRV_REQ_WRITE_UNCHANGED in filters, Max Reitz, 2018/04/21