diff options
| -rw-r--r-- | drivers/md/dm-mpath.c | 193 |
1 files changed, 128 insertions, 65 deletions
diff --git a/drivers/md/dm-mpath.c b/drivers/md/dm-mpath.c index f8aeaaa54afe..c70604a20897 100644 --- a/drivers/md/dm-mpath.c +++ b/drivers/md/dm-mpath.c @@ -8,7 +8,6 @@ #include <linux/device-mapper.h> #include "dm-path-selector.h" -#include "dm-bio-record.h" #include "dm-uevent.h" #include <linux/ctype.h> @@ -83,7 +82,7 @@ struct multipath { unsigned pg_init_count; /* Number of times pg_init called */ struct work_struct process_queued_ios; - struct bio_list queued_ios; + struct list_head queued_ios; unsigned queue_size; struct work_struct trigger_event; @@ -100,7 +99,6 @@ struct multipath { */ struct dm_mpath_io { struct pgpath *pgpath; - struct dm_bio_details details; size_t nr_bytes; }; @@ -194,6 +192,7 @@ static struct multipath *alloc_multipath(struct dm_target *ti) m = kzalloc(sizeof(*m), GFP_KERNEL); if (m) { INIT_LIST_HEAD(&m->priority_groups); + INIT_LIST_HEAD(&m->queued_ios); spin_lock_init(&m->lock); m->queue_io = 1; INIT_WORK(&m->process_queued_ios, process_queued_ios); @@ -318,13 +317,14 @@ static int __must_push_back(struct multipath *m) dm_noflush_suspending(m->ti)); } -static int map_io(struct multipath *m, struct bio *bio, +static int map_io(struct multipath *m, struct request *clone, struct dm_mpath_io *mpio, unsigned was_queued) { int r = DM_MAPIO_REMAPPED; - size_t nr_bytes = bio->bi_size; + size_t nr_bytes = blk_rq_bytes(clone); unsigned long flags; struct pgpath *pgpath; + struct block_device *bdev; spin_lock_irqsave(&m->lock, flags); @@ -341,16 +341,18 @@ static int map_io(struct multipath *m, struct bio *bio, if ((pgpath && m->queue_io) || (!pgpath && m->queue_if_no_path)) { /* Queue for the daemon to resubmit */ - bio_list_add(&m->queued_ios, bio); + list_add_tail(&clone->queuelist, &m->queued_ios); m->queue_size++; if ((m->pg_init_required && !m->pg_init_in_progress) || !m->queue_io) queue_work(kmultipathd, &m->process_queued_ios); pgpath = NULL; r = DM_MAPIO_SUBMITTED; - } else if (pgpath) - bio->bi_bdev = pgpath->path.dev->bdev; - else if (__must_push_back(m)) + } else if (pgpath) { + bdev = pgpath->path.dev->bdev; + clone->q = bdev_get_queue(bdev); + clone->rq_disk = bdev->bd_disk; + } else if (__must_push_back(m)) r = DM_MAPIO_REQUEUE; else r = -EIO; /* Failed */ @@ -398,30 +400,31 @@ static void dispatch_queued_ios(struct multipath *m) { int r; unsigned long flags; - struct bio *bio = NULL, *next; struct dm_mpath_io *mpio; union map_info *info; + struct request *clone, *n; + LIST_HEAD(cl); spin_lock_irqsave(&m->lock, flags); - bio = bio_list_get(&m->queued_ios); + list_splice_init(&m->queued_ios, &cl); spin_unlock_irqrestore(&m->lock, flags); - while (bio) { - next = bio->bi_next; - bio->bi_next = NULL; + list_for_each_entry_safe(clone, n, &cl, queuelist) { + list_del_init(&clone->queuelist); - info = dm_get_mapinfo(bio); + info = dm_get_rq_mapinfo(clone); mpio = info->ptr; - r = map_io(m, bio, mpio, 1); - if (r < 0) - bio_endio(bio, r); - else if (r == DM_MAPIO_REMAPPED) - generic_make_request(bio); - else if (r == DM_MAPIO_REQUEUE) - bio_endio(bio, -EIO); - - bio = next; + r = map_io(m, clone, mpio, 1); + if (r < 0) { + mempool_free(mpio, m->mpio_pool); + dm_kill_unmapped_request(clone, r); + } else if (r == DM_MAPIO_REMAPPED) + dm_dispatch_request(clone); + else if (r == DM_MAPIO_REQUEUE) { + mempool_free(mpio, m->mpio_pool); + dm_requeue_unmapped_request(clone); + } } } @@ -863,21 +866,24 @@ static void multipath_dtr(struct dm_target *ti) } /* - * Map bios, recording original fields for later in case we have to resubmit + * Map cloned requests */ -static int multipath_map(struct dm_target *ti, struct bio *bio, +static int multipath_map(struct dm_target *ti, struct request *clone, union map_info *map_context) { int r; struct dm_mpath_io *mpio; struct multipath *m = (struct multipath *) ti->private; - mpio = mempool_alloc(m->mpio_pool, GFP_NOIO); - dm_bio_record(&mpio->details, bio); + mpio = mempool_alloc(m->mpio_pool, GFP_ATOMIC); + if (!mpio) + /* ENOMEM, requeue */ + return DM_MAPIO_REQUEUE; + memset(mpio, 0, sizeof(*mpio)); map_context->ptr = mpio; - bio->bi_rw |= (1 << BIO_RW_FAILFAST_TRANSPORT); - r = map_io(m, bio, mpio, 0); + clone->cmd_flags |= REQ_FAILFAST_TRANSPORT; + r = map_io(m, clone, mpio, 0); if (r < 0 || r == DM_MAPIO_REQUEUE) mempool_free(mpio, m->mpio_pool); @@ -1158,53 +1164,41 @@ static void activate_path(struct work_struct *work) /* * end_io handling */ -static int do_end_io(struct multipath *m, struct bio *bio, +static int do_end_io(struct multipath *m, struct request *clone, int error, struct dm_mpath_io *mpio) { + /* + * We don't queue any clone request inside the multipath target + * during end I/O handling, since those clone requests don't have + * bio clones. If we queue them inside the multipath target, + * we need to make bio clones, that requires memory allocation. + * (See drivers/md/dm.c:end_clone_bio() about why the clone requests + * don't have bio clones.) + * Instead of queueing the clone request here, we queue the original + * request into dm core, which will remake a clone request and + * clone bios for it and resubmit it later. + */ + int r = DM_ENDIO_REQUEUE; unsigned long flags; - if (!error) + if (!error && !clone->errors) return 0; /* I/O complete */ - if ((error == -EWOULDBLOCK) && bio_rw_ahead(bio)) - return error; - if (error == -EOPNOTSUPP) return error; - spin_lock_irqsave(&m->lock, flags); - if (!m->nr_valid_paths) { - if (__must_push_back(m)) { - spin_unlock_irqrestore(&m->lock, flags); - return DM_ENDIO_REQUEUE; - } else if (!m->queue_if_no_path) { - spin_unlock_irqrestore(&m->lock, flags); - return -EIO; - } else { - spin_unlock_irqrestore(&m->lock, flags); - goto requeue; - } - } - spin_unlock_irqrestore(&m->lock, flags); - if (mpio->pgpath) fail_path(mpio->pgpath); - requeue: - dm_bio_restore(&mpio->details, bio); - - /* queue for the daemon to resubmit or fail */ spin_lock_irqsave(&m->lock, flags); - bio_list_add(&m->queued_ios, bio); - m->queue_size++; - if (!m->queue_io) - queue_work(kmultipathd, &m->process_queued_ios); + if (!m->nr_valid_paths && !m->queue_if_no_path && !__must_push_back(m)) + r = -EIO; spin_unlock_irqrestore(&m->lock, flags); - return DM_ENDIO_INCOMPLETE; /* io not complete */ + return r; } -static int multipath_end_io(struct dm_target *ti, struct bio *bio, +static int multipath_end_io(struct dm_target *ti, struct request *clone, int error, union map_info *map_context) { struct multipath *m = ti->private; @@ -1213,14 +1207,13 @@ static int multipath_end_io(struct dm_target *ti, struct bio *bio, struct path_selector *ps; int r; - r = do_end_io(m, bio, error, mpio); + r = do_end_io(m, clone, error, mpio); if (pgpath) { ps = &pgpath->pg->ps; if (ps->type->end_io) ps->type->end_io(ps, &pgpath->path, mpio->nr_bytes); } - if (r != DM_ENDIO_INCOMPLETE) - mempool_free(mpio, m->mpio_pool); + mempool_free(mpio, m->mpio_pool); return r; } @@ -1470,6 +1463,75 @@ out: return ret; } +static int __pgpath_busy(struct pgpath *pgpath) +{ + struct request_queue *q = bdev_get_queue(pgpath->path.dev->bdev); + + return dm_underlying_device_busy(q); +} + +/* + * We return "busy", only when we can map I/Os but underlying devices + * are busy (so even if we map I/Os now, the I/Os will wait on + * the underlying queue). + * In other words, if we want to kill I/Os or queue them inside us + * due to map unavailability, we don't return "busy". Otherwise, + * dm core won't give us the I/Os and we can't do what we want. + */ +static int multipath_busy(struct dm_target *ti) +{ + int busy = 0, has_active = 0; + struct multipath *m = ti->private; + struct priority_group *pg; + struct pgpath *pgpath; + unsigned long flags; + + spin_lock_irqsave(&m->lock, flags); + + /* Guess which priority_group will be used at next mapping time */ + if (unlikely(!m->current_pgpath && m->next_pg)) + pg = m->next_pg; + else if (likely(m->current_pg)) + pg = m->current_pg; + else + /* + * We don't know which pg will be used at next mapping time. + * We don't call __choose_pgpath() here to avoid to trigger + * pg_init just by busy checking. + * So we don't know whether underlying devices we will be using + * at next mapping time are busy or not. Just try mapping. + */ + goto out; + + /* + * If there is one non-busy active path at least, the path selector + * will be able to select it. So we consider such a pg as not busy. + */ + busy = 1; + list_for_each_entry(pgpath, &pg->pgpaths, list) + if (pgpath->is_active) { + has_active = 1; + + if (!__pgpath_busy(pgpath)) { + busy = 0; + break; + } + } + + if (!has_active) + /* + * No active path in this pg, so this pg won't be used and + * the current_pg will be changed at next mapping time. + * We need to try mapping to determine it. + */ + busy = 0; + +out: + spin_unlock_irqrestore(&m->lock, flags); + + return busy; +} + /*----------------------------------------------------------------- * Module setup *---------------------------------------------------------------*/ @@ -1479,14 +1541,15 @@ static struct target_type multipath_target = { .module = THIS_MODULE, .ctr = multipath_ctr, .dtr = multipath_dtr, - .map = multipath_map, - .end_io = multipath_end_io, + .map_rq = multipath_map, + .rq_end_io = multipath_end_io, .presuspend = multipath_presuspend, .resume = multipath_resume, .status = multipath_status, .message = multipath_message, .ioctl = multipath_ioctl, .iterate_devices = multipath_iterate_devices, + .busy = multipath_busy, }; static int __init dm_multipath_init(void) |