block: introduce BLKREPORTZONESV2 ioctl

block: introduce BLKREPORTZONESV2 ioctl

Introduce the new BLKREPORTZONESV2 ioctl command to allow user
applications access to the fast zone report implemented by
blkdev_report_zones_cached(). This new ioctl is defined as number 142
and is documented in include/uapi/linux/fs.h.

Unlike the existing BLKREPORTZONES ioctl, this new ioctl uses the flags
field of struct blk_zone_report also as an input. If the user sets the
BLK_ZONE_REP_CACHED flag as an input, then blkdev_report_zones_cached()
is used to generate the zone report using cached zone information. If
this flag is not set, then BLKREPORTZONESV2 behaves in the same manner
as BLKREPORTZONES and the zone report is generated by accessing the
zoned device.

Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>