dm: split discard requests on target boundaries
Update __clone_and_map_discard to loop across all targets in a DM
device's table when it processes a discard bio. If a discard crosses a
target boundary it must be split accordingly.
Update __issue_target_requests and __issue_target_request to allow a
cloned discard bio to have a custom start sector and size.
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 561313a..ac384b2 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -1193,7 +1193,7 @@
}
static void __issue_target_request(struct clone_info *ci, struct dm_target *ti,
- unsigned request_nr)
+ unsigned request_nr, sector_t len)
{
struct dm_target_io *tio = alloc_tio(ci, ti);
struct bio *clone;
@@ -1208,17 +1208,21 @@
clone = bio_alloc_bioset(GFP_NOIO, ci->bio->bi_max_vecs, ci->md->bs);
__bio_clone(clone, ci->bio);
clone->bi_destructor = dm_bio_destructor;
+ if (len) {
+ clone->bi_sector = ci->sector;
+ clone->bi_size = to_bytes(len);
+ }
__map_bio(ti, clone, tio);
}
static void __issue_target_requests(struct clone_info *ci, struct dm_target *ti,
- unsigned num_requests)
+ unsigned num_requests, sector_t len)
{
unsigned request_nr;
for (request_nr = 0; request_nr < num_requests; request_nr++)
- __issue_target_request(ci, ti, request_nr);
+ __issue_target_request(ci, ti, request_nr, len);
}
static int __clone_and_map_empty_barrier(struct clone_info *ci)
@@ -1227,7 +1231,7 @@
struct dm_target *ti;
while ((ti = dm_table_get_target(ci->map, target_nr++)))
- __issue_target_requests(ci, ti, ti->num_flush_requests);
+ __issue_target_requests(ci, ti, ti->num_flush_requests, 0);
ci->sector_count = 0;
@@ -1253,32 +1257,27 @@
static int __clone_and_map_discard(struct clone_info *ci)
{
struct dm_target *ti;
- sector_t max;
+ sector_t len;
- ti = dm_table_find_target(ci->map, ci->sector);
- if (!dm_target_is_valid(ti))
- return -EIO;
+ do {
+ ti = dm_table_find_target(ci->map, ci->sector);
+ if (!dm_target_is_valid(ti))
+ return -EIO;
- /*
- * Even though the device advertised discard support,
- * reconfiguration might have changed that since the
- * check was performed.
- */
-
- if (!ti->num_discard_requests)
- return -EOPNOTSUPP;
-
- max = max_io_len(ci->sector, ti);
-
- if (ci->sector_count > max)
/*
- * FIXME: Handle a discard that spans two or more targets.
+ * Even though the device advertised discard support,
+ * reconfiguration might have changed that since the
+ * check was performed.
*/
- return -EOPNOTSUPP;
+ if (!ti->num_discard_requests)
+ return -EOPNOTSUPP;
- __issue_target_requests(ci, ti, ti->num_discard_requests);
+ len = min(ci->sector_count, max_io_len_target_boundary(ci->sector, ti));
- ci->sector_count = 0;
+ __issue_target_requests(ci, ti, ti->num_discard_requests, len);
+
+ ci->sector += len;
+ } while (ci->sector_count -= len);
return 0;
}