[dm-devel] [PATCH v2 06/12] dm: split discard requests on target boundaries
Mike Snitzer
snitzer at redhat.com
Sat Jul 24 16:09:22 UTC 2010
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 at redhat.com>
---
drivers/md/dm.c | 51 ++++++++++++++++++++++++++++-----------------------
1 file changed, 28 insertions(+), 23 deletions(-)
Index: linux-2.6-block/drivers/md/dm.c
===================================================================
--- linux-2.6-block.orig/drivers/md/dm.c
+++ linux-2.6-block/drivers/md/dm.c
@@ -1191,7 +1191,7 @@ static struct dm_target_io *alloc_tio(st
}
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;
@@ -1206,17 +1206,21 @@ static void __issue_target_request(struc
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)
@@ -1225,7 +1229,7 @@ static int __clone_and_map_empty_barrier
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;
@@ -1251,30 +1255,31 @@ static void __clone_and_map_simple(struc
static int __clone_and_map_discard(struct clone_info *ci)
{
struct dm_target *ti;
- sector_t max;
-
- 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;
+ sector_t max, len, remaining = ci->sector_count;
+ unsigned offset = 0;
- max = max_io_len(ci->sector, ti);
+ do {
+ ti = dm_table_find_target(ci->map, ci->sector);
+ if (!dm_target_is_valid(ti))
+ return -EIO;
- 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;
+
+ max = max_io_len_target_boundary(ci->sector, ti, NULL);
+ len = min(remaining, max);
- __issue_target_requests(ci, ti, ti->num_discard_requests);
+ __issue_target_requests(ci, ti, ti->num_discard_requests, len);
+
+ ci->sector += len;
+ ci->sector_count -= len;
+ offset += to_bytes(len);
+ } while (remaining -= len);
ci->sector_count = 0;
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