Commit b6bcb844 authored by Mikulas Patocka's avatar Mikulas Patocka Committed by Mike Snitzer
Browse files

dm error: add discard support 



Add io_err_io_hints() and set discard limits so that the zero target
advertises support for discards.

The error target will return -EIO for discards.

This is useful when the user combines dm-error with other
discard-supporting targets in the same table; without dm-error
support, discards would be disabled for the whole combined device.

Signed-off-by: default avatarMikulas Patocka <mpatocka@redhat.com>
Tested-by: default avatarMilan Broz <gmazyland@gmail.com>
Signed-off-by: default avatarMike Snitzer <snitzer@kernel.org>
parent 00065f92

drivers/md/dm-target.c

+10 −1
Original line number Diff line number Diff line
@@ -119,6 +119,7 @@ static int io_err_ctr(struct dm_target *tt, unsigned int argc, char **args) 
	 * Return error for discards instead of -EOPNOTSUPP

	 */

	tt->num_discard_bios = 1;

	tt->discards_supported = true;



	return 0;

}
@@ -145,6 +146,13 @@ static void io_err_release_clone_rq(struct request *clone, 
{

}



static void io_err_io_hints(struct dm_target *ti, struct queue_limits *limits)

{

	limits->max_discard_sectors = UINT_MAX;

	limits->max_hw_discard_sectors = UINT_MAX;

	limits->discard_granularity = 512;

}



static long io_err_dax_direct_access(struct dm_target *ti, pgoff_t pgoff,

		long nr_pages, enum dax_access_mode mode, void **kaddr,

		pfn_t *pfn)
@@ -154,13 +162,14 @@ static long io_err_dax_direct_access(struct dm_target *ti, pgoff_t pgoff, 


static struct target_type error_target = {

	.name = "error",

	.version = {1, 5, 0},

	.version = {1, 6, 0},

	.features = DM_TARGET_WILDCARD,

	.ctr  = io_err_ctr,

	.dtr  = io_err_dtr,

	.map  = io_err_map,

	.clone_and_map_rq = io_err_clone_and_map_rq,

	.release_clone_rq = io_err_release_clone_rq,

	.io_hints = io_err_io_hints,

	.direct_access = io_err_dax_direct_access,

};