Re: [PATCH RFC 1/8] block: Introduce provisioning primitives

[Mike Snitzer <snitzer@redhat.com>]

On Thu, Sep 15 2022 at 12:48P -0400,
Sarthak Kukreti <sarthakkukreti@chromium.org> wrote:

> From: Sarthak Kukreti <sarthakkukreti@chromium.org>
> 
> Introduce block request REQ_OP_PROVISION. The intent of this request
> is to request underlying storage to preallocate disk space for the given
> block range. Block device that support this capability will export
> a provision limit within their request queues.
> 
> Signed-off-by: Sarthak Kukreti <sarthakkukreti@chromium.org>
> ---
>  block/blk-core.c          |  5 ++++
>  block/blk-lib.c           | 55 +++++++++++++++++++++++++++++++++++++++
>  block/blk-merge.c         | 17 ++++++++++++
>  block/blk-settings.c      | 19 ++++++++++++++
>  block/blk-sysfs.c         |  8 ++++++
>  block/bounce.c            |  1 +
>  include/linux/bio.h       |  6 +++--
>  include/linux/blk_types.h |  5 +++-
>  include/linux/blkdev.h    | 16 ++++++++++++
>  9 files changed, 129 insertions(+), 3 deletions(-)
> 
> diff --git a/block/blk-settings.c b/block/blk-settings.c
> index 8bb9eef5310e..be79ad68b330 100644
> --- a/block/blk-settings.c
> +++ b/block/blk-settings.c
> @@ -57,6 +57,7 @@ void blk_set_default_limits(struct queue_limits *lim)
>  	lim->misaligned = 0;
>  	lim->zoned = BLK_ZONED_NONE;
>  	lim->zone_write_granularity = 0;
> +	lim->max_provision_sectors = 0;
>  }
>  EXPORT_SYMBOL(blk_set_default_limits);
>  
> @@ -81,6 +82,7 @@ void blk_set_stacking_limits(struct queue_limits *lim)
>  	lim->max_dev_sectors = UINT_MAX;
>  	lim->max_write_zeroes_sectors = UINT_MAX;
>  	lim->max_zone_append_sectors = UINT_MAX;
> +	lim->max_provision_sectors = UINT_MAX;
>  }
>  EXPORT_SYMBOL(blk_set_stacking_limits);
>  

Please work through the blk_stack_limits() implementation too (simple
min_not_zero?).