For far layout, the discard region is not continuous on disks. So it needs
far copies r10bio to cover all regions. It needs a way to know all r10bios
have finish or not. Similar with raid10_sync_request, only the first r10bio
master_bio records the discard bio. Other r10bios master_bio record the
first r10bio. The first r10bio can finish after other r10bios finish and
then return the discard bio.
Signed-off-by: Xiao Ni <xni@xxxxxxxxxx>
---
drivers/md/raid10.c | 78 ++++++++++++++++++++++++++++++++++++++++-------------
drivers/md/raid10.h | 1 +
2 files changed, 60 insertions(+), 19 deletions(-)
diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index e059796..10be0f3 100644
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -1533,6 +1533,28 @@ static struct bio *raid10_split_bio(struct r10conf *conf,
return bio;
}
+static void raid_end_discard_bio(struct r10bio *r10bio)
+{
+ struct r10conf *conf = r10bio->mddev->private;
+ struct r10bio *first_r10bio;
+
+ while (atomic_dec_and_test(&r10bio->remaining)) {
+
+ allow_barrier(conf);
+
+ if (!test_bit(R10BIO_Discard, &r10bio->state)) {
+ first_r10bio = (struct r10bio *)r10bio->master_bio;
+ free_r10bio(r10bio);
+ r10bio = first_r10bio;
+ } else {
+ md_write_end(r10bio->mddev);
+ bio_endio(r10bio->master_bio);
+ free_r10bio(r10bio);
+ break;
+ }
+ }
+}
+
static void raid10_end_discard_request(struct bio *bio)
{
struct r10bio *r10_bio = bio->bi_private;
@@ -1559,11 +1581,7 @@ static void raid10_end_discard_request(struct bio *bio)
rdev = conf->mirrors[dev].rdev;
}
- if (atomic_dec_and_test(&r10_bio->remaining)) {
- md_write_end(r10_bio->mddev);
- raid_end_bio_io(r10_bio);
- }
-
+ raid_end_discard_bio(r10_bio);
rdev_dec_pending(rdev, conf->mddev);
}
@@ -1576,7 +1594,9 @@ static int raid10_handle_discard(struct mddev *mddev, struct bio *bio)
{
struct r10conf *conf = mddev->private;
struct geom *geo = &conf->geo;
- struct r10bio *r10_bio;
+ struct r10bio *r10_bio, *first_r10bio;
+ int far_copies = geo->far_copies;
+ bool first_copy = true;
int disk;
sector_t chunk;
@@ -1635,16 +1655,6 @@ static int raid10_handle_discard(struct mddev *mddev, struct bio *bio)
bio = raid10_split_bio(conf, bio, split_size, true);
}
- r10_bio = mempool_alloc(&conf->r10bio_pool, GFP_NOIO);
- r10_bio->mddev = mddev;
- r10_bio->state = 0;
- r10_bio->sectors = 0;
- memset(r10_bio->devs, 0, sizeof(r10_bio->devs[0]) * geo->raid_disks);
-
- wait_blocked_dev(mddev, r10_bio);
-
- r10_bio->master_bio = bio;
-
bio_start = bio->bi_iter.bi_sector;
bio_end = bio_end_sector(bio);
@@ -1670,6 +1680,28 @@ static int raid10_handle_discard(struct mddev *mddev, struct bio *bio)
end_disk_offset = (bio_end & geo->chunk_mask) +
(last_stripe_index << geo->chunk_shift);
+retry_discard:
+ r10_bio = mempool_alloc(&conf->r10bio_pool, GFP_NOIO);
+ r10_bio->mddev = mddev;
+ r10_bio->state = 0;
+ r10_bio->sectors = 0;
+ memset(r10_bio->devs, 0, sizeof(r10_bio->devs[0]) * geo->raid_disks);
+ wait_blocked_dev(mddev, r10_bio);
+
+ /* For far layout it needs more than one r10bio to cover all regions.
+ * Inspired by raid10_sync_request, we can use the first r10bio->master_bio
+ * to record the discard bio. Other r10bio->master_bio record the first
+ * r10bio. The first r10bio only release after all other r10bios finish.
+ * The discard bio returns only first r10bio finishes
+ */
+ if (first_copy) {
+ r10_bio->master_bio = bio;
+ set_bit(R10BIO_Discard, &r10_bio->state);
+ first_copy = false;
+ first_r10bio = r10_bio;
+ } else
+ r10_bio->master_bio = (struct bio *)first_r10bio;
+
rcu_read_lock();
for (disk = 0; disk < geo->raid_disks; disk++) {
struct md_rdev *rdev = rcu_dereference(conf->mirrors[disk].rdev);
@@ -1760,11 +1792,19 @@ static int raid10_handle_discard(struct mddev *mddev, struct bio *bio)
}
}
- if (atomic_dec_and_test(&r10_bio->remaining)) {
- md_write_end(r10_bio->mddev);
- raid_end_bio_io(r10_bio);
+ if (!geo->far_offset && --far_copies) {
+ first_stripe_index += geo->stride >> geo->chunk_shift;
+ start_disk_offset += geo->stride;
+ last_stripe_index += geo->stride >> geo->chunk_shift;
+ end_disk_offset += geo->stride;
+ atomic_inc(&first_r10bio->remaining);
+ raid_end_discard_bio(r10_bio);
+ wait_barrier(conf);
+ goto retry_discard;
}
+ raid_end_discard_bio(r10_bio);
+
return 0;
out:
allow_barrier(conf);
diff --git a/drivers/md/raid10.h b/drivers/md/raid10.h
index 79cd2b7..1461fd5 100644
--- a/drivers/md/raid10.h
+++ b/drivers/md/raid10.h
@@ -179,5 +179,6 @@ enum r10bio_state {
R10BIO_Previous,
/* failfast devices did receive failfast requests. */
R10BIO_FailFast,
+ R10BIO_Discard,
};
#endif
--
2.7.5
