Re: [PATCH v10 4/9] copy-on-read: pass base node name to COR driver

[Vladimir Sementsov-Ogievskiy]

29.09.2020 15:38, Andrey Shinkevich wrote:
> To limit the guest's COR operations by the base node in the backing

Better to drop "guest's " word. We don't to limit the guest in any

> chain during stream job, pass the base node name to the copy-on-read
> driver. The rest of the functionality will be implemented in the patch
> that follows.

Oops. Seems we want bottom-node, not base, in according with stream job

> Signed-off-by: Andrey Shinkevich <andrey.shinkevich@virtuozzo.com>
> ---
>   block/copy-on-read.c | 13 +++++++++++++
>   1 file changed, 13 insertions(+)
>
> diff --git a/block/copy-on-read.c b/block/copy-on-read.c
> index 3c8231f..e04092f 100644
> --- a/block/copy-on-read.c
> +++ b/block/copy-on-read.c
> @@ -24,19 +24,23 @@
>   #include "block/block_int.h"
>   #include "qemu/module.h"
>   #include "qapi/error.h"
> +#include "qapi/qmp/qerror.h"
>   #include "qapi/qmp/qdict.h"
>   #include "block/copy-on-read.h"
>   
>   
>   typedef struct BDRVStateCOR {
>       bool active;
> +    BlockDriverState *base_bs;
>   } BDRVStateCOR;
>   
>   
>   static int cor_open(BlockDriverState *bs, QDict *options, int flags,
>                       Error **errp)
>   {
> +    BlockDriverState *base_bs = NULL;
>       BDRVStateCOR *state = bs->opaque;
> +    const char *base_node = qdict_get_try_str(options, "base");
>   
>       bs->file = bdrv_open_child(NULL, options, "file", bs, &child_of_bds,
>                                  BDRV_CHILD_FILTERED | BDRV_CHILD_PRIMARY,
> @@ -52,7 +56,16 @@ static int cor_open(BlockDriverState *bs, QDict *options, 
> int flags,
>           ((BDRV_REQ_FUA | BDRV_REQ_MAY_UNMAP | BDRV_REQ_NO_FALLBACK) &
>               bs->file->bs->supported_zero_flags);
>   
> +    if (base_node) {
> +        qdict_del(options, "base");
> +        base_bs = bdrv_lookup_bs(NULL, base_node, errp);
> +        if (!base_bs) {
> +            error_setg(errp, QERR_BASE_NOT_FOUND, base_node);
> +            return -EINVAL;
> +        }
> +    }
>       state->active = true;
> +    state->base_bs = base_bs;
>   
>       /*
>        * We don't need to call bdrv_child_refresh_perms() now as the permissions


--
Best regards,
Vladimir