Re: [PATCH for-5.0 02/31] block: Add BdrvChildRole

[Vladimir Sementsov-Ogievskiy]

27.11.2019 16:15, Max Reitz wrote:
> This enum will supplement BdrvChildClass when it comes to what role (or
> combination of roles) a child takes for its parent.
> 
> Because empty enums are not allowed, let us just start with it filled.
> 
> Signed-off-by: Max Reitz <address@hidden>
> ---
>   include/block/block.h | 38 ++++++++++++++++++++++++++++++++++++++
>   1 file changed, 38 insertions(+)
> 
> diff --git a/include/block/block.h b/include/block/block.h
> index 38963ef203..36817d5689 100644
> --- a/include/block/block.h
> +++ b/include/block/block.h
> @@ -279,6 +279,44 @@ enum {
>       DEFAULT_PERM_UNCHANGED      = BLK_PERM_ALL & ~DEFAULT_PERM_PASSTHROUGH,
>   };
>   
> +typedef enum BdrvChildRole {

Don't you want to call it just BdrvChildFlags ?
Benefits:

1. Do not intersect with old BdrvChildRole.
2. I think, BDRV_CHILD_STAY_AT_NODE is not a role, but just a property or flag..

> +    /*
> +     * If present, bdrv_replace_node() will not change the node this
> +     * BdrvChild points to.
> +     */
> +    BDRV_CHILD_STAY_AT_NODE = (1 << 0),
> +
> +    /* Child stores data */
> +    BDRV_CHILD_DATA         = (1 << 1),
> +
> +    /* Child stores metadata */
> +    BDRV_CHILD_METADATA     = (1 << 2),
> +
> +    /* Filtered child */
> +    BDRV_CHILD_FILTERED     = (1 << 3),
> +
> +    /* Child to COW from (backing child) */
> +    BDRV_CHILD_COW          = (1 << 4),
> +
> +    /* Child is expected to be a protocol node */
> +    BDRV_CHILD_PROTOCOL     = (1 << 5),
> +
> +    /* Child is expected to be a format node */
> +    BDRV_CHILD_FORMAT       = (1 << 6),
> +
> +    /*
> +     * The primary child.  For most drivers, this is the child whose
> +     * filename applies best to the parent node.
> +     */
> +    BDRV_CHILD_PRIMARY      = (1 << 7),
> +
> +    /* Useful combination of flags */
> +    BDRV_CHILD_IMAGE        = BDRV_CHILD_DATA
> +                              | BDRV_CHILD_METADATA
> +                              | BDRV_CHILD_PROTOCOL
> +                              | BDRV_CHILD_PRIMARY,
> +} BdrvChildRole;
> +
>   char *bdrv_perm_names(uint64_t perm);
>   uint64_t bdrv_qapi_perm_to_blk_perm(BlockPermission qapi_perm);
>   
> 


-- 
Best regards,
Vladimir