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: Mikulas Patocka <mpatocka@redhat.com>
Tested-by: Milan Broz <gmazyland@gmail.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
This commit is contained in:
Mikulas Patocka 2023-04-04 11:22:10 -04:00 committed by Mike Snitzer
parent 00065f925e
commit b6bcb84446

View File

@ -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 * Return error for discards instead of -EOPNOTSUPP
*/ */
tt->num_discard_bios = 1; tt->num_discard_bios = 1;
tt->discards_supported = true;
return 0; 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, static long io_err_dax_direct_access(struct dm_target *ti, pgoff_t pgoff,
long nr_pages, enum dax_access_mode mode, void **kaddr, long nr_pages, enum dax_access_mode mode, void **kaddr,
pfn_t *pfn) 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 = { static struct target_type error_target = {
.name = "error", .name = "error",
.version = {1, 5, 0}, .version = {1, 6, 0},
.features = DM_TARGET_WILDCARD, .features = DM_TARGET_WILDCARD,
.ctr = io_err_ctr, .ctr = io_err_ctr,
.dtr = io_err_dtr, .dtr = io_err_dtr,
.map = io_err_map, .map = io_err_map,
.clone_and_map_rq = io_err_clone_and_map_rq, .clone_and_map_rq = io_err_clone_and_map_rq,
.release_clone_rq = io_err_release_clone_rq, .release_clone_rq = io_err_release_clone_rq,
.io_hints = io_err_io_hints,
.direct_access = io_err_dax_direct_access, .direct_access = io_err_dax_direct_access,
}; };