From 4184153f9e483f9bb63339ed316e059962fe9794 Mon Sep 17 00:00:00 2001 From: Mikulas Patocka Date: Thu, 10 Dec 2009 23:51:59 +0000 Subject: [PATCH] dm raid1: support flush Flush support for dm-raid1. When it receives an empty barrier, submit it to all the devices via dm-io. Signed-off-by: Mikulas Patocka Signed-off-by: Alasdair G Kergon --- drivers/md/dm-raid1.c | 13 +++++++++++-- drivers/md/dm-region-hash.c | 25 +++++++++++++++++++++++-- 2 files changed, 34 insertions(+), 4 deletions(-) diff --git a/drivers/md/dm-raid1.c b/drivers/md/dm-raid1.c index cc9dc79b078..752a29e1855 100644 --- a/drivers/md/dm-raid1.c +++ b/drivers/md/dm-raid1.c @@ -396,6 +396,8 @@ static int mirror_available(struct mirror_set *ms, struct bio *bio) */ static sector_t map_sector(struct mirror *m, struct bio *bio) { + if (unlikely(!bio->bi_size)) + return 0; return m->offset + (bio->bi_sector - m->ms->ti->begin); } @@ -562,7 +564,7 @@ static void do_write(struct mirror_set *ms, struct bio *bio) struct dm_io_region io[ms->nr_mirrors], *dest = io; struct mirror *m; struct dm_io_request io_req = { - .bi_rw = WRITE, + .bi_rw = WRITE | (bio->bi_rw & WRITE_BARRIER), .mem.type = DM_IO_BVEC, .mem.ptr.bvec = bio->bi_io_vec + bio->bi_idx, .notify.fn = write_callback, @@ -603,6 +605,11 @@ static void do_writes(struct mirror_set *ms, struct bio_list *writes) bio_list_init(&requeue); while ((bio = bio_list_pop(writes))) { + if (unlikely(bio_empty_barrier(bio))) { + bio_list_add(&sync, bio); + continue; + } + region = dm_rh_bio_to_region(ms->rh, bio); if (log->type->is_remote_recovering && @@ -995,6 +1002,7 @@ static int mirror_ctr(struct dm_target *ti, unsigned int argc, char **argv) ti->private = ms; ti->split_io = dm_rh_get_region_size(ms->rh); + ti->num_flush_requests = 1; ms->kmirrord_wq = create_singlethread_workqueue("kmirrord"); if (!ms->kmirrord_wq) { @@ -1122,7 +1130,8 @@ static int mirror_end_io(struct dm_target *ti, struct bio *bio, * We need to dec pending if this was a write. */ if (rw == WRITE) { - dm_rh_dec(ms->rh, map_context->ll); + if (likely(!bio_empty_barrier(bio))) + dm_rh_dec(ms->rh, map_context->ll); return error; } diff --git a/drivers/md/dm-region-hash.c b/drivers/md/dm-region-hash.c index 36dbe29f2fd..00806b760cc 100644 --- a/drivers/md/dm-region-hash.c +++ b/drivers/md/dm-region-hash.c @@ -79,6 +79,11 @@ struct dm_region_hash { struct list_head recovered_regions; struct list_head failed_recovered_regions; + /* + * If there was a barrier failure no regions can be marked clean. + */ + int barrier_failure; + void *context; sector_t target_begin; @@ -211,6 +216,7 @@ struct dm_region_hash *dm_region_hash_create( INIT_LIST_HEAD(&rh->quiesced_regions); INIT_LIST_HEAD(&rh->recovered_regions); INIT_LIST_HEAD(&rh->failed_recovered_regions); + rh->barrier_failure = 0; rh->region_pool = mempool_create_kmalloc_pool(MIN_REGIONS, sizeof(struct dm_region)); @@ -395,6 +401,11 @@ void dm_rh_mark_nosync(struct dm_region_hash *rh, region_t region = dm_rh_bio_to_region(rh, bio); int recovering = 0; + if (bio_empty_barrier(bio)) { + rh->barrier_failure = 1; + return; + } + /* We must inform the log that the sync count has changed. */ log->type->set_region_sync(log, region, 0); @@ -515,8 +526,11 @@ void dm_rh_inc_pending(struct dm_region_hash *rh, struct bio_list *bios) { struct bio *bio; - for (bio = bios->head; bio; bio = bio->bi_next) + for (bio = bios->head; bio; bio = bio->bi_next) { + if (bio_empty_barrier(bio)) + continue; rh_inc(rh, dm_rh_bio_to_region(rh, bio)); + } } EXPORT_SYMBOL_GPL(dm_rh_inc_pending); @@ -544,7 +558,14 @@ void dm_rh_dec(struct dm_region_hash *rh, region_t region) */ /* do nothing for DM_RH_NOSYNC */ - if (reg->state == DM_RH_RECOVERING) { + if (unlikely(rh->barrier_failure)) { + /* + * If a write barrier failed some time ago, we + * don't know whether or not this write made it + * to the disk, so we must resync the device. + */ + reg->state = DM_RH_NOSYNC; + } else if (reg->state == DM_RH_RECOVERING) { list_add_tail(®->list, &rh->quiesced_regions); } else if (reg->state == DM_RH_DIRTY) { reg->state = DM_RH_CLEAN; -- 2.20.1