From: John Garry Currently diskstats for partitions are never updated: $ ./fio_read nvme1n1p1 # run traffic on /dev/nvme1n1p1 ... $ more /proc/diskstats | grep nvme1 259 2 nvme1c1n1 49857 0 400344 768565 0 0 0 0 0 2334 768565 0 0 0 0 0 0 259 3 nvme1n1 99710 0 800680 1599285 0 0 0 0 0 2346 1599285 0 0 0 0 0 0 259 5 nvme1n1p1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 259 4 nvme1c2n1 49853 0 400336 831472 0 0 0 0 0 2315 831472 0 0 0 0 0 0 This is because we only ever update the diskstats for the multipath disk in nvme_mpath_end_request(), and we never take into account that the original bi_bdev may been a partition of this disk. Functions bdev_start_io_acct() and bdev_start_io_acct() do handle updating diskstats for a partition, in that they also update the whole disk also (if a partition), so use the partition (if applicable) when calling those functions. Change any functionality which used to lookup the gendisk part0 to now lookup the specific gendisk partition. Signed-off-by: John Garry --- drivers/nvme/host/core.c | 1 + drivers/nvme/host/multipath.c | 51 ++++++++++++++++++++++++++++------- 2 files changed, 42 insertions(+), 10 deletions(-) diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c index 1322c678f4eb8..b94b9a3bceb28 100644 --- a/drivers/nvme/host/core.c +++ b/drivers/nvme/host/core.c @@ -4273,6 +4273,7 @@ static void nvme_alloc_ns(struct nvme_ctrl *ctrl, struct nvme_ns_info *info) sprintf(disk->disk_name, "nvme%dc%dn%d", ctrl->subsys->instance, ctrl->instance, ns->head->instance); disk->flags |= GENHD_FL_HIDDEN; + disk_add_mirror(ns->head->disk, ns->disk); } else if (multipath) { sprintf(disk->disk_name, "nvme%dn%d", ctrl->subsys->instance, ns->head->instance); diff --git a/drivers/nvme/host/multipath.c b/drivers/nvme/host/multipath.c index 75dbb58286a32..bd4056f1a9f28 100644 --- a/drivers/nvme/host/multipath.c +++ b/drivers/nvme/host/multipath.c @@ -144,6 +144,23 @@ void nvme_mpath_start_freeze(struct nvme_subsystem *subsys) blk_freeze_queue_start(h->disk->queue); } +static struct block_device *nvme_disk_to_part(struct gendisk *disk, + u8 partno) +{ + /* Quick lookup for whole disk */ + if (!partno) + return disk->part0; + return xa_load(&disk->part_tbl, partno); +} + +static struct block_device *nvme_to_disk_part(struct gendisk *disk, + struct block_device *bdev) +{ + if (!bdev) + return disk->part0; + return nvme_disk_to_part(disk, bdev_partno(bdev)); +} + void nvme_failover_req(struct request *req) { struct nvme_ns *ns = req->q->queuedata; @@ -165,8 +182,10 @@ void nvme_failover_req(struct request *req) } spin_lock_irqsave(&ns->head->requeue_lock, flags); - for (bio = req->bio; bio; bio = bio->bi_next) - bio_set_dev(bio, ns->head->disk->part0); + for (bio = req->bio; bio; bio = bio->bi_next) { + bio_set_dev(bio, nvme_to_disk_part(ns->head->disk, + bio->bi_bdev)); + } blk_steal_bios(&ns->head->requeue_list, req); spin_unlock_irqrestore(&ns->head->requeue_lock, flags); @@ -194,8 +213,9 @@ void nvme_mpath_start_request(struct request *rq) return; nvme_req(rq)->flags |= NVME_MPATH_IO_STATS; - nvme_req(rq)->start_time = bdev_start_io_acct(disk->part0, req_op(rq), - jiffies); + nvme_req(rq)->start_time = bdev_start_io_acct( + nvme_to_disk_part(disk, rq->part), + req_op(rq), jiffies); } EXPORT_SYMBOL_GPL(nvme_mpath_start_request); @@ -208,7 +228,8 @@ void nvme_mpath_end_request(struct request *rq) if (!(nvme_req(rq)->flags & NVME_MPATH_IO_STATS)) return; - bdev_end_io_acct(ns->head->disk->part0, req_op(rq), + bdev_end_io_acct(nvme_to_disk_part(ns->head->disk, + rq->part), req_op(rq), blk_rq_bytes(rq) >> SECTOR_SHIFT, nvme_req(rq)->start_time); } @@ -530,11 +551,21 @@ static bool nvme_available_path(struct nvme_ns_head *head) return nvme_mpath_queue_if_no_path(head); } +static struct block_device *nvme_find_path_bdev(struct nvme_ns_head *head, + u8 partno) +{ + struct nvme_ns *ns = nvme_find_path(head); + + if (!ns) + return NULL; + return nvme_disk_to_part(ns->disk, partno); +} + static void nvme_ns_head_submit_bio(struct bio *bio) { struct nvme_ns_head *head = bio->bi_bdev->bd_disk->private_data; struct device *dev = disk_to_dev(head->disk); - struct nvme_ns *ns; + struct block_device *bdev; int srcu_idx; /* @@ -547,9 +578,9 @@ static void nvme_ns_head_submit_bio(struct bio *bio) return; srcu_idx = srcu_read_lock(&head->srcu); - ns = nvme_find_path(head); - if (likely(ns)) { - bio_set_dev(bio, ns->disk->part0); + bdev = nvme_find_path_bdev(head, bdev_partno(bio->bi_bdev)); + if (likely(bdev)) { + bio_set_dev(bio, bdev); /* * Use BIO_REMAPPED to skip bio_check_eod() when this bio * enters submit_bio_noacct() for the per-path device. The EOD @@ -557,7 +588,7 @@ static void nvme_ns_head_submit_bio(struct bio *bio) */ bio_set_flag(bio, BIO_REMAPPED); bio->bi_opf |= REQ_NVME_MPATH; - trace_block_bio_remap(bio, disk_devt(ns->head->disk), + trace_block_bio_remap(bio, disk_devt(head->disk), bio->bi_iter.bi_sector); submit_bio_noacct(bio); } else if (nvme_available_path(head)) { -- 2.43.7