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Re: [PATCH v11 08/13] copy-on-read: add support for BDRV_REQ_PREFETCH to
From: |
Max Reitz |
Subject: |
Re: [PATCH v11 08/13] copy-on-read: add support for BDRV_REQ_PREFETCH to COR-filter |
Date: |
Wed, 14 Oct 2020 14:40:20 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.11.0 |
On 12.10.20 19:43, Andrey Shinkevich wrote:
> Add support for the BDRV_REQ_PREFETCH flag to the supported_write_flags
s/write/read/
> of the COR-filter.
>
> Signed-off-by: Andrey Shinkevich <andrey.shinkevich@virtuozzo.com>
> ---
> block/copy-on-read.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/block/copy-on-read.c b/block/copy-on-read.c
> index dfbd6ad..b136895 100644
> --- a/block/copy-on-read.c
> +++ b/block/copy-on-read.c
> @@ -50,6 +50,7 @@ static int cor_open(BlockDriverState *bs, QDict *options,
> int flags,
> return -EINVAL;
> }
>
> + bs->supported_read_flags = BDRV_REQ_PREFETCH;
> bs->supported_write_flags = BDRV_REQ_WRITE_UNCHANGED |
> (BDRV_REQ_FUA & bs->file->bs->supported_write_flags);
Then we mustn’t let cor_co_preadv_part() pass the flag on to
bdrv_co_preadv_part() unless BDRV_REQ_COPY_ON_READ is set, too. I
suspect the following patch is going to do that, but in the meantime the
code is wrong.
Perhaps just swap both patches?
And by the way, I’m also missing a patch that makes the block layer
evaluate supported_read_flags and e.g. strip BDRV_REQ_PREFETCH if it
isn’t supported, before it gets passed to such a block driver.
Max
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- Re: [PATCH v11 05/13] copy-on-read: limit COR operations to base in COR driver, (continued)
[PATCH v11 06/13] block: modify the comment for BDRV_REQ_PREFETCH flag, Andrey Shinkevich, 2020/10/12
[PATCH v11 07/13] block: include supported_read_flags into BDS structure, Andrey Shinkevich, 2020/10/12
[PATCH v11 08/13] copy-on-read: add support for BDRV_REQ_PREFETCH to COR-filter, Andrey Shinkevich, 2020/10/12
- Re: [PATCH v11 08/13] copy-on-read: add support for BDRV_REQ_PREFETCH to COR-filter,
Max Reitz <=
[PATCH v11 09/13] copy-on-read: skip non-guest reads if no copy needed, Andrey Shinkevich, 2020/10/12
Re: [PATCH v11 09/13] copy-on-read: skip non-guest reads if no copy needed, Andrey Shinkevich, 2020/10/21
Re: [PATCH v11 09/13] copy-on-read: skip non-guest reads if no copy needed, Andrey Shinkevich, 2020/10/22
Re: [PATCH v11 09/13] copy-on-read: skip non-guest reads if no copy needed, Vladimir Sementsov-Ogievskiy, 2020/10/22
Re: [PATCH v11 09/13] copy-on-read: skip non-guest reads if no copy needed, Andrey Shinkevich, 2020/10/14