From fc9977dd069e4f82fcacb262652117c488647319 Mon Sep 17 00:00:00 2001 From: NeilBrown Date: Wed, 5 Apr 2017 14:05:51 +1000 Subject: md/raid10: simplify the splitting of requests. raid10 splits requests in two different ways for two different reasons. First, bio_split() is used to ensure the bio fits with a chunk. Second, multiple r10bio structures are allocated to represent the different sections that need to go to different devices, to avoid known bad blocks. This can be simplified to just use bio_split() once, and not to use multiple r10bios. We delay the split until we know a maximum bio size that can be handled with a single r10bio, and then split the bio and queue the remainder for later handling. As with raid1, we allocate a new bio_set to help with the splitting. It is not correct to use fs_bio_set in a device driver. Signed-off-by: NeilBrown Signed-off-by: Shaohua Li --- drivers/md/raid10.c | 164 ++++++++++++++++------------------------------------ 1 file changed, 50 insertions(+), 114 deletions(-) (limited to 'drivers/md/raid10.c') diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c index e055ec9..41845ba 100644 --- a/drivers/md/raid10.c +++ b/drivers/md/raid10.c @@ -1127,7 +1127,6 @@ static void raid10_read_request(struct mddev *mddev, struct bio *bio, struct bio *read_bio; const int op = bio_op(bio); const unsigned long do_sync = (bio->bi_opf & REQ_SYNC); - int sectors_handled; int max_sectors; sector_t sectors; struct md_rdev *rdev; @@ -1140,7 +1139,7 @@ static void raid10_read_request(struct mddev *mddev, struct bio *bio, */ wait_barrier(conf); - sectors = bio_sectors(bio); + sectors = r10_bio->sectors; while (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery) && bio->bi_iter.bi_sector < conf->reshape_progress && bio->bi_iter.bi_sector + sectors > conf->reshape_progress) { @@ -1157,17 +1156,23 @@ static void raid10_read_request(struct mddev *mddev, struct bio *bio, wait_barrier(conf); } -read_again: rdev = read_balance(conf, r10_bio, &max_sectors); if (!rdev) { raid_end_bio_io(r10_bio); return; } + if (max_sectors < bio_sectors(bio)) { + struct bio *split = bio_split(bio, max_sectors, + GFP_NOIO, conf->bio_split); + bio_chain(split, bio); + generic_make_request(bio); + bio = split; + r10_bio->master_bio = bio; + r10_bio->sectors = max_sectors; + } slot = r10_bio->read_slot; read_bio = bio_clone_fast(bio, GFP_NOIO, mddev->bio_set); - bio_trim(read_bio, r10_bio->sector - bio->bi_iter.bi_sector, - max_sectors); r10_bio->devs[slot].bio = read_bio; r10_bio->devs[slot].rdev = rdev; @@ -1186,40 +1191,13 @@ read_again: trace_block_bio_remap(bdev_get_queue(read_bio->bi_bdev), read_bio, disk_devt(mddev->gendisk), r10_bio->sector); - if (max_sectors < r10_bio->sectors) { - /* - * Could not read all from this device, so we will need another - * r10_bio. - */ - sectors_handled = (r10_bio->sector + max_sectors - - bio->bi_iter.bi_sector); - r10_bio->sectors = max_sectors; - inc_pending(conf); - bio_inc_remaining(bio); - /* - * Cannot call generic_make_request directly as that will be - * queued in __generic_make_request and subsequent - * mempool_alloc might block waiting for it. so hand bio over - * to raid10d. - */ - reschedule_retry(r10_bio); - - r10_bio = mempool_alloc(conf->r10bio_pool, GFP_NOIO); - - r10_bio->master_bio = bio; - r10_bio->sectors = bio_sectors(bio) - sectors_handled; - r10_bio->state = 0; - r10_bio->mddev = mddev; - r10_bio->sector = bio->bi_iter.bi_sector + sectors_handled; - goto read_again; - } else - generic_make_request(read_bio); + generic_make_request(read_bio); return; } static void raid10_write_one_disk(struct mddev *mddev, struct r10bio *r10_bio, struct bio *bio, bool replacement, - int n_copy, int max_sectors) + int n_copy) { const int op = bio_op(bio); const unsigned long do_sync = (bio->bi_opf & REQ_SYNC); @@ -1243,7 +1221,6 @@ static void raid10_write_one_disk(struct mddev *mddev, struct r10bio *r10_bio, rdev = conf->mirrors[devnum].rdev; mbio = bio_clone_fast(bio, GFP_NOIO, mddev->bio_set); - bio_trim(mbio, r10_bio->sector - bio->bi_iter.bi_sector, max_sectors); if (replacement) r10_bio->devs[n_copy].repl_bio = mbio; else @@ -1294,7 +1271,6 @@ static void raid10_write_request(struct mddev *mddev, struct bio *bio, int i; struct md_rdev *blocked_rdev; sector_t sectors; - int sectors_handled; int max_sectors; md_write_start(mddev, bio); @@ -1306,7 +1282,7 @@ static void raid10_write_request(struct mddev *mddev, struct bio *bio, */ wait_barrier(conf); - sectors = bio_sectors(bio); + sectors = r10_bio->sectors; while (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery) && bio->bi_iter.bi_sector < conf->reshape_progress && bio->bi_iter.bi_sector + sectors > conf->reshape_progress) { @@ -1476,44 +1452,29 @@ retry_write: if (max_sectors < r10_bio->sectors) r10_bio->sectors = max_sectors; - sectors_handled = r10_bio->sector + max_sectors - - bio->bi_iter.bi_sector; + + if (r10_bio->sectors < bio_sectors(bio)) { + struct bio *split = bio_split(bio, r10_bio->sectors, + GFP_NOIO, conf->bio_split); + bio_chain(split, bio); + generic_make_request(bio); + bio = split; + r10_bio->master_bio = bio; + } atomic_set(&r10_bio->remaining, 1); bitmap_startwrite(mddev->bitmap, r10_bio->sector, r10_bio->sectors, 0); for (i = 0; i < conf->copies; i++) { if (r10_bio->devs[i].bio) - raid10_write_one_disk(mddev, r10_bio, bio, false, - i, max_sectors); + raid10_write_one_disk(mddev, r10_bio, bio, false, i); if (r10_bio->devs[i].repl_bio) - raid10_write_one_disk(mddev, r10_bio, bio, true, - i, max_sectors); - } - - /* Don't remove the bias on 'remaining' (one_write_done) until - * after checking if we need to go around again. - */ - - if (sectors_handled < bio_sectors(bio)) { - /* We need another r10_bio and it needs to be counted */ - inc_pending(conf); - bio_inc_remaining(bio); - one_write_done(r10_bio); - r10_bio = mempool_alloc(conf->r10bio_pool, GFP_NOIO); - - r10_bio->master_bio = bio; - r10_bio->sectors = bio_sectors(bio) - sectors_handled; - - r10_bio->mddev = mddev; - r10_bio->sector = bio->bi_iter.bi_sector + sectors_handled; - r10_bio->state = 0; - goto retry_write; + raid10_write_one_disk(mddev, r10_bio, bio, true, i); } one_write_done(r10_bio); } -static void __make_request(struct mddev *mddev, struct bio *bio) +static void __make_request(struct mddev *mddev, struct bio *bio, int sectors) { struct r10conf *conf = mddev->private; struct r10bio *r10_bio; @@ -1521,7 +1482,7 @@ static void __make_request(struct mddev *mddev, struct bio *bio) r10_bio = mempool_alloc(conf->r10bio_pool, GFP_NOIO); r10_bio->master_bio = bio; - r10_bio->sectors = bio_sectors(bio); + r10_bio->sectors = sectors; r10_bio->mddev = mddev; r10_bio->sector = bio->bi_iter.bi_sector; @@ -1538,54 +1499,26 @@ static void raid10_make_request(struct mddev *mddev, struct bio *bio) struct r10conf *conf = mddev->private; sector_t chunk_mask = (conf->geo.chunk_mask & conf->prev.chunk_mask); int chunk_sects = chunk_mask + 1; - - struct bio *split; + int sectors = bio_sectors(bio); if (unlikely(bio->bi_opf & REQ_PREFLUSH)) { md_flush_request(mddev, bio); return; } - do { - - /* - * If this request crosses a chunk boundary, we need to split - * it. - */ - if (unlikely((bio->bi_iter.bi_sector & chunk_mask) + - bio_sectors(bio) > chunk_sects - && (conf->geo.near_copies < conf->geo.raid_disks - || conf->prev.near_copies < - conf->prev.raid_disks))) { - split = bio_split(bio, chunk_sects - - (bio->bi_iter.bi_sector & - (chunk_sects - 1)), - GFP_NOIO, fs_bio_set); - bio_chain(split, bio); - } else { - split = bio; - } - - /* - * If a bio is splitted, the first part of bio will pass - * barrier but the bio is queued in current->bio_list (see - * generic_make_request). If there is a raise_barrier() called - * here, the second part of bio can't pass barrier. But since - * the first part bio isn't dispatched to underlaying disks - * yet, the barrier is never released, hence raise_barrier will - * alays wait. We have a deadlock. - * Note, this only happens in read path. For write path, the - * first part of bio is dispatched in a schedule() call - * (because of blk plug) or offloaded to raid10d. - * Quitting from the function immediately can change the bio - * order queued in bio_list and avoid the deadlock. - */ - __make_request(mddev, split); - if (split != bio && bio_data_dir(bio) == READ) { - generic_make_request(bio); - break; - } - } while (split != bio); + /* + * If this request crosses a chunk boundary, we need to split + * it. + */ + if (unlikely((bio->bi_iter.bi_sector & chunk_mask) + + sectors > chunk_sects + && (conf->geo.near_copies < conf->geo.raid_disks + || conf->prev.near_copies < + conf->prev.raid_disks))) + sectors = chunk_sects - + (bio->bi_iter.bi_sector & + (chunk_sects - 1)); + __make_request(mddev, bio, sectors); /* In case raid10d snuck in to freeze_array */ wake_up(&conf->wait_barrier); @@ -2873,13 +2806,8 @@ static void raid10d(struct md_thread *thread) recovery_request_write(mddev, r10_bio); else if (test_bit(R10BIO_ReadError, &r10_bio->state)) handle_read_error(mddev, r10_bio); - else { - /* just a partial read to be scheduled from a - * separate context - */ - int slot = r10_bio->read_slot; - generic_make_request(r10_bio->devs[slot].bio); - } + else + WARN_ON_ONCE(1); cond_resched(); if (mddev->sb_flags & ~(1<r10bio_pool) goto out; + conf->bio_split = bioset_create(BIO_POOL_SIZE, 0); + if (!conf->bio_split) + goto out; + calc_sectors(conf, mddev->dev_sectors); if (mddev->reshape_position == MaxSector) { conf->prev = conf->geo; @@ -3689,6 +3621,8 @@ static struct r10conf *setup_conf(struct mddev *mddev) mempool_destroy(conf->r10bio_pool); kfree(conf->mirrors); safe_put_page(conf->tmppage); + if (conf->bio_split) + bioset_free(conf->bio_split); kfree(conf); } return ERR_PTR(err); @@ -3899,6 +3833,8 @@ static void raid10_free(struct mddev *mddev, void *priv) kfree(conf->mirrors); kfree(conf->mirrors_old); kfree(conf->mirrors_new); + if (conf->bio_split) + bioset_free(conf->bio_split); kfree(conf); } -- cgit v1.1