From d3ee2d8415a6256c1c41e1be36e80e640c3e6359 Mon Sep 17 00:00:00 2001 From: Xiao Ni Date: Wed, 2 Sep 2020 20:00:23 +0800 Subject: [PATCH] md/raid10: improve discard request for far layout 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 Signed-off-by: Song Liu --- drivers/md/raid10.c | 86 +++++++++++++++++++++++++++++++++------------ drivers/md/raid10.h | 1 + 2 files changed, 64 insertions(+), 23 deletions(-) diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c index 05773ee1b5ba..b7bca6703df8 100644 --- a/drivers/md/raid10.c +++ b/drivers/md/raid10.c @@ -1534,6 +1534,28 @@ 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; @@ -1560,11 +1582,7 @@ 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); } @@ -1577,7 +1595,9 @@ 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; @@ -1616,30 +1636,20 @@ static int raid10_handle_discard(struct mddev *mddev, struct bio *bio) if (bio_sectors(bio) < stripe_size*2) goto out; - /* For far offset layout, if bio is not aligned with stripe size, it splits - * the part that is not aligned with strip size. + /* For far and far offset layout, if bio is not aligned with stripe size, + * it splits the part that is not aligned with strip size. */ div_u64_rem(bio_start, stripe_size, &remainder); - if (geo->far_offset && remainder) { + if ((far_copies > 1) && remainder) { split_size = stripe_size - remainder; bio = raid10_split_bio(conf, bio, split_size, false); } div_u64_rem(bio_end, stripe_size, &remainder); - if (geo->far_offset && remainder) { + if ((far_copies > 1) && remainder) { split_size = bio_sectors(bio) - remainder; 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); @@ -1665,6 +1675,28 @@ 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); @@ -1755,11 +1787,19 @@ 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 79cd2b7d3128..1461fd55311b 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