From ad4068de49862b083ac2a15bc50689bb30ce3e44 Mon Sep 17 00:00:00 2001 From: majianpeng Date: Thu, 14 Nov 2013 15:16:15 +1100 Subject: raid5: Use slow_path to release stripe when mddev->thread is null When release_stripe() is called in grow_one_stripe(), the mddev->thread is null. So it will omit one wakeup this thread to release stripe. For this condition, use slow_path to release stripe. Bug was introduced in 3.12 Cc: stable@vger.kernel.org (3.12+) Fixes: 773ca82fa1ee58dd1bf88b Signed-off-by: Jianpeng Ma Signed-off-by: NeilBrown diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c index f8b9068..f013d36 100644 --- a/drivers/md/raid5.c +++ b/drivers/md/raid5.c @@ -340,7 +340,8 @@ static void release_stripe(struct stripe_head *sh) unsigned long flags; bool wakeup; - if (test_and_set_bit(STRIPE_ON_RELEASE_LIST, &sh->state)) + if (unlikely(!conf->mddev->thread) || + test_and_set_bit(STRIPE_ON_RELEASE_LIST, &sh->state)) goto slow_path; wakeup = llist_add(&sh->release_list, &conf->released_stripes); if (wakeup) -- cgit v0.10.2 From 02e5f5c0a0f726e66e3d8506ea1691e344277969 Mon Sep 17 00:00:00 2001 From: NeilBrown Date: Thu, 14 Nov 2013 15:16:15 +1100 Subject: md: fix calculation of stacking limits on level change. The various ->run routines of md personalities assume that the 'queue' has been initialised by the blk_set_stacking_limits() call in md_alloc(). However when the level is changed (by level_store()) the ->run routine for the new level is called for an array which has already had the stacking limits modified. This can result in incorrect final settings. So call blk_set_stacking_limits() before ->run in level_store(). A specific consequence of this bug is that it causes discard_granularity to be set incorrectly when reshaping a RAID4 to a RAID0. This is suitable for any -stable kernel since 3.3 in which blk_set_stacking_limits() was introduced. Cc: stable@vger.kernel.org (3.3+) Reported-and-tested-by: "Baldysiak, Pawel" Signed-off-by: NeilBrown diff --git a/drivers/md/md.c b/drivers/md/md.c index 2445fec..1975c2d 100644 --- a/drivers/md/md.c +++ b/drivers/md/md.c @@ -3620,6 +3620,7 @@ level_store(struct mddev *mddev, const char *buf, size_t len) mddev->in_sync = 1; del_timer_sync(&mddev->safemode_timer); } + blk_set_stacking_limits(&mddev->queue->limits); pers->run(mddev); set_bit(MD_CHANGE_DEVS, &mddev->flags); mddev_resume(mddev); -- cgit v0.10.2 From ba8805b97320416e7c5bb8f55d2bd06d5c319e7d Mon Sep 17 00:00:00 2001 From: NeilBrown Date: Thu, 14 Nov 2013 15:16:15 +1100 Subject: md/raid5.c: add proper locking to error path of raid5_start_reshape. If raid5_start_reshape errors out, we need to reset all the fields that were updated (not just some), and need to use the seq_counter to ensure make_request() doesn't use an inconsitent state. Signed-off-by: NeilBrown diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c index f013d36..4bbcb7e 100644 --- a/drivers/md/raid5.c +++ b/drivers/md/raid5.c @@ -6384,12 +6384,18 @@ static int raid5_start_reshape(struct mddev *mddev) if (!mddev->sync_thread) { mddev->recovery = 0; spin_lock_irq(&conf->device_lock); + write_seqcount_begin(&conf->gen_lock); mddev->raid_disks = conf->raid_disks = conf->previous_raid_disks; + mddev->new_chunk_sectors = + conf->chunk_sectors = conf->prev_chunk_sectors; + mddev->new_layout = conf->algorithm = conf->prev_algo; rdev_for_each(rdev, mddev) rdev->new_data_offset = rdev->data_offset; smp_wmb(); + conf->generation --; conf->reshape_progress = MaxSector; mddev->reshape_position = MaxSector; + write_seqcount_end(&conf->gen_lock); spin_unlock_irq(&conf->device_lock); return -EAGAIN; } -- cgit v0.10.2 From 82e06c811163c4d853ed335d56c3378088bc89cc Mon Sep 17 00:00:00 2001 From: Shaohua Li Date: Thu, 14 Nov 2013 15:16:16 +1100 Subject: wait: add wait_event_cmd() Add a new API wait_event_cmd(). It's a variant of wait_even() with two commands executed. One is executed before sleep, another after sleep. Modified to match use wait.h approach based on suggestion by Peter Zijlstra - neilb Signed-off-by: Shaohua Li Signed-off-by: NeilBrown diff --git a/include/linux/wait.h b/include/linux/wait.h index 61939ba..eaa00b1 100644 --- a/include/linux/wait.h +++ b/include/linux/wait.h @@ -278,6 +278,31 @@ do { \ __ret; \ }) +#define __wait_event_cmd(wq, condition, cmd1, cmd2) \ + (void)___wait_event(wq, condition, TASK_UNINTERRUPTIBLE, 0, 0, \ + cmd1; schedule(); cmd2) + +/** + * wait_event_cmd - sleep until a condition gets true + * @wq: the waitqueue to wait on + * @condition: a C expression for the event to wait for + * cmd1: the command will be executed before sleep + * cmd2: the command will be executed after sleep + * + * The process is put to sleep (TASK_UNINTERRUPTIBLE) until the + * @condition evaluates to true. The @condition is checked each time + * the waitqueue @wq is woken up. + * + * wake_up() has to be called after changing any variable that could + * change the result of the wait condition. + */ +#define wait_event_cmd(wq, condition, cmd1, cmd2) \ +do { \ + if (condition) \ + break; \ + __wait_event_cmd(wq, condition, cmd1, cmd2); \ +} while (0) + #define __wait_event_interruptible(wq, condition) \ ___wait_event(wq, condition, TASK_INTERRUPTIBLE, 0, 0, \ schedule()) -- cgit v0.10.2 From 566c09c53455d7c4f1130928ef8071da1a24ea65 Mon Sep 17 00:00:00 2001 From: Shaohua Li Date: Thu, 14 Nov 2013 15:16:17 +1100 Subject: raid5: relieve lock contention in get_active_stripe() get_active_stripe() is the last place we have lock contention. It has two paths. One is stripe isn't found and new stripe is allocated, the other is stripe is found. The first path basically calls __find_stripe and init_stripe. It accesses conf->generation, conf->previous_raid_disks, conf->raid_disks, conf->prev_chunk_sectors, conf->chunk_sectors, conf->max_degraded, conf->prev_algo, conf->algorithm, the stripe_hashtbl and inactive_list. Except stripe_hashtbl and inactive_list, other fields are changed very rarely. With this patch, we split inactive_list and add new hash locks. Each free stripe belongs to a specific inactive list. Which inactive list is determined by stripe's lock_hash. Note, even a stripe hasn't a sector assigned, it has a lock_hash assigned. Stripe's inactive list is protected by a hash lock, which is determined by it's lock_hash too. The lock_hash is derivied from current stripe_hashtbl hash, which guarantees any stripe_hashtbl list will be assigned to a specific lock_hash, so we can use new hash lock to protect stripe_hashtbl list too. The goal of the new hash locks introduced is we can only use the new locks in the first path of get_active_stripe(). Since we have several hash locks, lock contention is relieved significantly. The first path of get_active_stripe() accesses other fields, since they are changed rarely, changing them now need take conf->device_lock and all hash locks. For a slow path, this isn't a problem. If we need lock device_lock and hash lock, we always lock hash lock first. The tricky part is release_stripe and friends. We need take device_lock first. Neil's suggestion is we put inactive stripes to a temporary list and readd it to inactive_list after device_lock is released. In this way, we add stripes to temporary list with device_lock hold and remove stripes from the list with hash lock hold. So we don't allow concurrent access to the temporary list, which means we need allocate temporary list for all participants of release_stripe. One downside is free stripes are maintained in their inactive list, they can't across between the lists. By default, we have total 256 stripes and 8 lists, so each list will have 32 stripes. It's possible one list has free stripe but other list hasn't. The chance should be rare because stripes allocation are even distributed. And we can always allocate more stripes for cache, several mega bytes memory isn't a big deal. This completely removes the lock contention of the first path of get_active_stripe(). It slows down the second code path a little bit though because we now need takes two locks, but since the hash lock isn't contended, the overhead should be quite small (several atomic instructions). The second path of get_active_stripe() (basically sequential write or big request size randwrite) still has lock contentions. Signed-off-by: Shaohua Li Signed-off-by: NeilBrown diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c index 4bbcb7e..93090b2 100644 --- a/drivers/md/raid5.c +++ b/drivers/md/raid5.c @@ -85,6 +85,42 @@ static inline struct hlist_head *stripe_hash(struct r5conf *conf, sector_t sect) return &conf->stripe_hashtbl[hash]; } +static inline int stripe_hash_locks_hash(sector_t sect) +{ + return (sect >> STRIPE_SHIFT) & STRIPE_HASH_LOCKS_MASK; +} + +static inline void lock_device_hash_lock(struct r5conf *conf, int hash) +{ + spin_lock_irq(conf->hash_locks + hash); + spin_lock(&conf->device_lock); +} + +static inline void unlock_device_hash_lock(struct r5conf *conf, int hash) +{ + spin_unlock(&conf->device_lock); + spin_unlock_irq(conf->hash_locks + hash); +} + +static inline void lock_all_device_hash_locks_irq(struct r5conf *conf) +{ + int i; + local_irq_disable(); + spin_lock(conf->hash_locks); + for (i = 1; i < NR_STRIPE_HASH_LOCKS; i++) + spin_lock_nest_lock(conf->hash_locks + i, conf->hash_locks); + spin_lock(&conf->device_lock); +} + +static inline void unlock_all_device_hash_locks_irq(struct r5conf *conf) +{ + int i; + spin_unlock(&conf->device_lock); + for (i = NR_STRIPE_HASH_LOCKS; i; i--) + spin_unlock(conf->hash_locks + i - 1); + local_irq_enable(); +} + /* bio's attached to a stripe+device for I/O are linked together in bi_sector * order without overlap. There may be several bio's per stripe+device, and * a bio could span several devices. @@ -249,7 +285,8 @@ static void raid5_wakeup_stripe_thread(struct stripe_head *sh) } } -static void do_release_stripe(struct r5conf *conf, struct stripe_head *sh) +static void do_release_stripe(struct r5conf *conf, struct stripe_head *sh, + struct list_head *temp_inactive_list) { BUG_ON(!list_empty(&sh->lru)); BUG_ON(atomic_read(&conf->active_stripes)==0); @@ -278,19 +315,60 @@ static void do_release_stripe(struct r5conf *conf, struct stripe_head *sh) < IO_THRESHOLD) md_wakeup_thread(conf->mddev->thread); atomic_dec(&conf->active_stripes); - if (!test_bit(STRIPE_EXPANDING, &sh->state)) { - list_add_tail(&sh->lru, &conf->inactive_list); - wake_up(&conf->wait_for_stripe); - if (conf->retry_read_aligned) - md_wakeup_thread(conf->mddev->thread); - } + if (!test_bit(STRIPE_EXPANDING, &sh->state)) + list_add_tail(&sh->lru, temp_inactive_list); } } -static void __release_stripe(struct r5conf *conf, struct stripe_head *sh) +static void __release_stripe(struct r5conf *conf, struct stripe_head *sh, + struct list_head *temp_inactive_list) { if (atomic_dec_and_test(&sh->count)) - do_release_stripe(conf, sh); + do_release_stripe(conf, sh, temp_inactive_list); +} + +/* + * @hash could be NR_STRIPE_HASH_LOCKS, then we have a list of inactive_list + * + * Be careful: Only one task can add/delete stripes from temp_inactive_list at + * given time. Adding stripes only takes device lock, while deleting stripes + * only takes hash lock. + */ +static void release_inactive_stripe_list(struct r5conf *conf, + struct list_head *temp_inactive_list, + int hash) +{ + int size; + bool do_wakeup = false; + unsigned long flags; + + if (hash == NR_STRIPE_HASH_LOCKS) { + size = NR_STRIPE_HASH_LOCKS; + hash = NR_STRIPE_HASH_LOCKS - 1; + } else + size = 1; + while (size) { + struct list_head *list = &temp_inactive_list[size - 1]; + + /* + * We don't hold any lock here yet, get_active_stripe() might + * remove stripes from the list + */ + if (!list_empty_careful(list)) { + spin_lock_irqsave(conf->hash_locks + hash, flags); + list_splice_tail_init(list, conf->inactive_list + hash); + do_wakeup = true; + spin_unlock_irqrestore(conf->hash_locks + hash, flags); + } + size--; + hash--; + } + + if (do_wakeup) { + wake_up(&conf->wait_for_stripe); + if (conf->retry_read_aligned) + md_wakeup_thread(conf->mddev->thread); + } } static struct llist_node *llist_reverse_order(struct llist_node *head) @@ -308,7 +386,8 @@ static struct llist_node *llist_reverse_order(struct llist_node *head) } /* should hold conf->device_lock already */ -static int release_stripe_list(struct r5conf *conf) +static int release_stripe_list(struct r5conf *conf, + struct list_head *temp_inactive_list) { struct stripe_head *sh; int count = 0; @@ -317,6 +396,8 @@ static int release_stripe_list(struct r5conf *conf) head = llist_del_all(&conf->released_stripes); head = llist_reverse_order(head); while (head) { + int hash; + sh = llist_entry(head, struct stripe_head, release_list); head = llist_next(head); /* sh could be readded after STRIPE_ON_RELEASE_LIST is cleard */ @@ -327,7 +408,8 @@ static int release_stripe_list(struct r5conf *conf) * again, the count is always > 1. This is true for * STRIPE_ON_UNPLUG_LIST bit too. */ - __release_stripe(conf, sh); + hash = sh->hash_lock_index; + __release_stripe(conf, sh, &temp_inactive_list[hash]); count++; } @@ -338,6 +420,8 @@ static void release_stripe(struct stripe_head *sh) { struct r5conf *conf = sh->raid_conf; unsigned long flags; + struct list_head list; + int hash; bool wakeup; if (unlikely(!conf->mddev->thread) || @@ -351,8 +435,11 @@ slow_path: local_irq_save(flags); /* we are ok here if STRIPE_ON_RELEASE_LIST is set or not */ if (atomic_dec_and_lock(&sh->count, &conf->device_lock)) { - do_release_stripe(conf, sh); + INIT_LIST_HEAD(&list); + hash = sh->hash_lock_index; + do_release_stripe(conf, sh, &list); spin_unlock(&conf->device_lock); + release_inactive_stripe_list(conf, &list, hash); } local_irq_restore(flags); } @@ -377,18 +464,19 @@ static inline void insert_hash(struct r5conf *conf, struct stripe_head *sh) /* find an idle stripe, make sure it is unhashed, and return it. */ -static struct stripe_head *get_free_stripe(struct r5conf *conf) +static struct stripe_head *get_free_stripe(struct r5conf *conf, int hash) { struct stripe_head *sh = NULL; struct list_head *first; - if (list_empty(&conf->inactive_list)) + if (list_empty(conf->inactive_list + hash)) goto out; - first = conf->inactive_list.next; + first = (conf->inactive_list + hash)->next; sh = list_entry(first, struct stripe_head, lru); list_del_init(first); remove_hash(sh); atomic_inc(&conf->active_stripes); + BUG_ON(hash != sh->hash_lock_index); out: return sh; } @@ -431,7 +519,7 @@ static void stripe_set_idx(sector_t stripe, struct r5conf *conf, int previous, static void init_stripe(struct stripe_head *sh, sector_t sector, int previous) { struct r5conf *conf = sh->raid_conf; - int i; + int i, seq; BUG_ON(atomic_read(&sh->count) != 0); BUG_ON(test_bit(STRIPE_HANDLE, &sh->state)); @@ -441,7 +529,8 @@ static void init_stripe(struct stripe_head *sh, sector_t sector, int previous) (unsigned long long)sh->sector); remove_hash(sh); - +retry: + seq = read_seqcount_begin(&conf->gen_lock); sh->generation = conf->generation - previous; sh->disks = previous ? conf->previous_raid_disks : conf->raid_disks; sh->sector = sector; @@ -463,6 +552,8 @@ static void init_stripe(struct stripe_head *sh, sector_t sector, int previous) dev->flags = 0; raid5_build_block(sh, i, previous); } + if (read_seqcount_retry(&conf->gen_lock, seq)) + goto retry; insert_hash(conf, sh); sh->cpu = smp_processor_id(); } @@ -567,29 +658,31 @@ get_active_stripe(struct r5conf *conf, sector_t sector, int previous, int noblock, int noquiesce) { struct stripe_head *sh; + int hash = stripe_hash_locks_hash(sector); pr_debug("get_stripe, sector %llu\n", (unsigned long long)sector); - spin_lock_irq(&conf->device_lock); + spin_lock_irq(conf->hash_locks + hash); do { wait_event_lock_irq(conf->wait_for_stripe, conf->quiesce == 0 || noquiesce, - conf->device_lock); + *(conf->hash_locks + hash)); sh = __find_stripe(conf, sector, conf->generation - previous); if (!sh) { if (!conf->inactive_blocked) - sh = get_free_stripe(conf); + sh = get_free_stripe(conf, hash); if (noblock && sh == NULL) break; if (!sh) { conf->inactive_blocked = 1; - wait_event_lock_irq(conf->wait_for_stripe, - !list_empty(&conf->inactive_list) && - (atomic_read(&conf->active_stripes) - < (conf->max_nr_stripes *3/4) - || !conf->inactive_blocked), - conf->device_lock); + wait_event_lock_irq( + conf->wait_for_stripe, + !list_empty(conf->inactive_list + hash) && + (atomic_read(&conf->active_stripes) + < (conf->max_nr_stripes * 3 / 4) + || !conf->inactive_blocked), + *(conf->hash_locks + hash)); conf->inactive_blocked = 0; } else init_stripe(sh, sector, previous); @@ -600,9 +693,11 @@ get_active_stripe(struct r5conf *conf, sector_t sector, && !test_bit(STRIPE_ON_UNPLUG_LIST, &sh->state) && !test_bit(STRIPE_ON_RELEASE_LIST, &sh->state)); } else { + spin_lock(&conf->device_lock); if (!test_bit(STRIPE_HANDLE, &sh->state)) atomic_inc(&conf->active_stripes); if (list_empty(&sh->lru) && + !test_bit(STRIPE_ON_RELEASE_LIST, &sh->state) && !test_bit(STRIPE_EXPANDING, &sh->state)) BUG(); list_del_init(&sh->lru); @@ -610,6 +705,7 @@ get_active_stripe(struct r5conf *conf, sector_t sector, sh->group->stripes_cnt--; sh->group = NULL; } + spin_unlock(&conf->device_lock); } } } while (sh == NULL); @@ -617,7 +713,7 @@ get_active_stripe(struct r5conf *conf, sector_t sector, if (sh) atomic_inc(&sh->count); - spin_unlock_irq(&conf->device_lock); + spin_unlock_irq(conf->hash_locks + hash); return sh; } @@ -1597,7 +1693,7 @@ static void raid_run_ops(struct stripe_head *sh, unsigned long ops_request) put_cpu(); } -static int grow_one_stripe(struct r5conf *conf) +static int grow_one_stripe(struct r5conf *conf, int hash) { struct stripe_head *sh; sh = kmem_cache_zalloc(conf->slab_cache, GFP_KERNEL); @@ -1613,6 +1709,7 @@ static int grow_one_stripe(struct r5conf *conf) kmem_cache_free(conf->slab_cache, sh); return 0; } + sh->hash_lock_index = hash; /* we just created an active stripe so... */ atomic_set(&sh->count, 1); atomic_inc(&conf->active_stripes); @@ -1625,6 +1722,7 @@ static int grow_stripes(struct r5conf *conf, int num) { struct kmem_cache *sc; int devs = max(conf->raid_disks, conf->previous_raid_disks); + int hash; if (conf->mddev->gendisk) sprintf(conf->cache_name[0], @@ -1642,9 +1740,13 @@ static int grow_stripes(struct r5conf *conf, int num) return 1; conf->slab_cache = sc; conf->pool_size = devs; - while (num--) - if (!grow_one_stripe(conf)) + hash = conf->max_nr_stripes % NR_STRIPE_HASH_LOCKS; + while (num--) { + if (!grow_one_stripe(conf, hash)) return 1; + conf->max_nr_stripes++; + hash = (hash + 1) % NR_STRIPE_HASH_LOCKS; + } return 0; } @@ -1702,6 +1804,7 @@ static int resize_stripes(struct r5conf *conf, int newsize) int err; struct kmem_cache *sc; int i; + int hash, cnt; if (newsize <= conf->pool_size) return 0; /* never bother to shrink */ @@ -1741,19 +1844,29 @@ static int resize_stripes(struct r5conf *conf, int newsize) * OK, we have enough stripes, start collecting inactive * stripes and copying them over */ + hash = 0; + cnt = 0; list_for_each_entry(nsh, &newstripes, lru) { - spin_lock_irq(&conf->device_lock); - wait_event_lock_irq(conf->wait_for_stripe, - !list_empty(&conf->inactive_list), - conf->device_lock); - osh = get_free_stripe(conf); - spin_unlock_irq(&conf->device_lock); + lock_device_hash_lock(conf, hash); + wait_event_cmd(conf->wait_for_stripe, + !list_empty(conf->inactive_list + hash), + unlock_device_hash_lock(conf, hash), + lock_device_hash_lock(conf, hash)); + osh = get_free_stripe(conf, hash); + unlock_device_hash_lock(conf, hash); atomic_set(&nsh->count, 1); for(i=0; ipool_size; i++) nsh->dev[i].page = osh->dev[i].page; for( ; idev[i].page = NULL; + nsh->hash_lock_index = hash; kmem_cache_free(conf->slab_cache, osh); + cnt++; + if (cnt >= conf->max_nr_stripes / NR_STRIPE_HASH_LOCKS + + !!((conf->max_nr_stripes % NR_STRIPE_HASH_LOCKS) > hash)) { + hash++; + cnt = 0; + } } kmem_cache_destroy(conf->slab_cache); @@ -1812,13 +1925,13 @@ static int resize_stripes(struct r5conf *conf, int newsize) return err; } -static int drop_one_stripe(struct r5conf *conf) +static int drop_one_stripe(struct r5conf *conf, int hash) { struct stripe_head *sh; - spin_lock_irq(&conf->device_lock); - sh = get_free_stripe(conf); - spin_unlock_irq(&conf->device_lock); + spin_lock_irq(conf->hash_locks + hash); + sh = get_free_stripe(conf, hash); + spin_unlock_irq(conf->hash_locks + hash); if (!sh) return 0; BUG_ON(atomic_read(&sh->count)); @@ -1830,8 +1943,10 @@ static int drop_one_stripe(struct r5conf *conf) static void shrink_stripes(struct r5conf *conf) { - while (drop_one_stripe(conf)) - ; + int hash; + for (hash = 0; hash < NR_STRIPE_HASH_LOCKS; hash++) + while (drop_one_stripe(conf, hash)) + ; if (conf->slab_cache) kmem_cache_destroy(conf->slab_cache); @@ -3915,7 +4030,8 @@ static void raid5_activate_delayed(struct r5conf *conf) } } -static void activate_bit_delay(struct r5conf *conf) +static void activate_bit_delay(struct r5conf *conf, + struct list_head *temp_inactive_list) { /* device_lock is held */ struct list_head head; @@ -3923,9 +4039,11 @@ static void activate_bit_delay(struct r5conf *conf) list_del_init(&conf->bitmap_list); while (!list_empty(&head)) { struct stripe_head *sh = list_entry(head.next, struct stripe_head, lru); + int hash; list_del_init(&sh->lru); atomic_inc(&sh->count); - __release_stripe(conf, sh); + hash = sh->hash_lock_index; + __release_stripe(conf, sh, &temp_inactive_list[hash]); } } @@ -3941,7 +4059,7 @@ int md_raid5_congested(struct mddev *mddev, int bits) return 1; if (conf->quiesce) return 1; - if (list_empty_careful(&conf->inactive_list)) + if (atomic_read(&conf->active_stripes) == conf->max_nr_stripes) return 1; return 0; @@ -4271,6 +4389,7 @@ static struct stripe_head *__get_priority_stripe(struct r5conf *conf, int group) struct raid5_plug_cb { struct blk_plug_cb cb; struct list_head list; + struct list_head temp_inactive_list[NR_STRIPE_HASH_LOCKS]; }; static void raid5_unplug(struct blk_plug_cb *blk_cb, bool from_schedule) @@ -4281,6 +4400,7 @@ static void raid5_unplug(struct blk_plug_cb *blk_cb, bool from_schedule) struct mddev *mddev = cb->cb.data; struct r5conf *conf = mddev->private; int cnt = 0; + int hash; if (cb->list.next && !list_empty(&cb->list)) { spin_lock_irq(&conf->device_lock); @@ -4298,11 +4418,14 @@ static void raid5_unplug(struct blk_plug_cb *blk_cb, bool from_schedule) * STRIPE_ON_RELEASE_LIST could be set here. In that * case, the count is always > 1 here */ - __release_stripe(conf, sh); + hash = sh->hash_lock_index; + __release_stripe(conf, sh, &cb->temp_inactive_list[hash]); cnt++; } spin_unlock_irq(&conf->device_lock); } + release_inactive_stripe_list(conf, cb->temp_inactive_list, + NR_STRIPE_HASH_LOCKS); if (mddev->queue) trace_block_unplug(mddev->queue, cnt, !from_schedule); kfree(cb); @@ -4323,8 +4446,12 @@ static void release_stripe_plug(struct mddev *mddev, cb = container_of(blk_cb, struct raid5_plug_cb, cb); - if (cb->list.next == NULL) + if (cb->list.next == NULL) { + int i; INIT_LIST_HEAD(&cb->list); + for (i = 0; i < NR_STRIPE_HASH_LOCKS; i++) + INIT_LIST_HEAD(cb->temp_inactive_list + i); + } if (!test_and_set_bit(STRIPE_ON_UNPLUG_LIST, &sh->state)) list_add_tail(&sh->lru, &cb->list); @@ -4969,27 +5096,45 @@ static int retry_aligned_read(struct r5conf *conf, struct bio *raid_bio) } static int handle_active_stripes(struct r5conf *conf, int group, - struct r5worker *worker) + struct r5worker *worker, + struct list_head *temp_inactive_list) { struct stripe_head *batch[MAX_STRIPE_BATCH], *sh; - int i, batch_size = 0; + int i, batch_size = 0, hash; + bool release_inactive = false; while (batch_size < MAX_STRIPE_BATCH && (sh = __get_priority_stripe(conf, group)) != NULL) batch[batch_size++] = sh; - if (batch_size == 0) - return batch_size; + if (batch_size == 0) { + for (i = 0; i < NR_STRIPE_HASH_LOCKS; i++) + if (!list_empty(temp_inactive_list + i)) + break; + if (i == NR_STRIPE_HASH_LOCKS) + return batch_size; + release_inactive = true; + } spin_unlock_irq(&conf->device_lock); + release_inactive_stripe_list(conf, temp_inactive_list, + NR_STRIPE_HASH_LOCKS); + + if (release_inactive) { + spin_lock_irq(&conf->device_lock); + return 0; + } + for (i = 0; i < batch_size; i++) handle_stripe(batch[i]); cond_resched(); spin_lock_irq(&conf->device_lock); - for (i = 0; i < batch_size; i++) - __release_stripe(conf, batch[i]); + for (i = 0; i < batch_size; i++) { + hash = batch[i]->hash_lock_index; + __release_stripe(conf, batch[i], &temp_inactive_list[hash]); + } return batch_size; } @@ -5010,9 +5155,10 @@ static void raid5_do_work(struct work_struct *work) while (1) { int batch_size, released; - released = release_stripe_list(conf); + released = release_stripe_list(conf, worker->temp_inactive_list); - batch_size = handle_active_stripes(conf, group_id, worker); + batch_size = handle_active_stripes(conf, group_id, worker, + worker->temp_inactive_list); worker->working = false; if (!batch_size && !released) break; @@ -5051,7 +5197,7 @@ static void raid5d(struct md_thread *thread) struct bio *bio; int batch_size, released; - released = release_stripe_list(conf); + released = release_stripe_list(conf, conf->temp_inactive_list); if ( !list_empty(&conf->bitmap_list)) { @@ -5061,7 +5207,7 @@ static void raid5d(struct md_thread *thread) bitmap_unplug(mddev->bitmap); spin_lock_irq(&conf->device_lock); conf->seq_write = conf->seq_flush; - activate_bit_delay(conf); + activate_bit_delay(conf, conf->temp_inactive_list); } raid5_activate_delayed(conf); @@ -5075,7 +5221,8 @@ static void raid5d(struct md_thread *thread) handled++; } - batch_size = handle_active_stripes(conf, ANY_GROUP, NULL); + batch_size = handle_active_stripes(conf, ANY_GROUP, NULL, + conf->temp_inactive_list); if (!batch_size && !released) break; handled += batch_size; @@ -5111,22 +5258,29 @@ raid5_set_cache_size(struct mddev *mddev, int size) { struct r5conf *conf = mddev->private; int err; + int hash; if (size <= 16 || size > 32768) return -EINVAL; + hash = (conf->max_nr_stripes - 1) % NR_STRIPE_HASH_LOCKS; while (size < conf->max_nr_stripes) { - if (drop_one_stripe(conf)) + if (drop_one_stripe(conf, hash)) conf->max_nr_stripes--; else break; + hash--; + if (hash < 0) + hash = NR_STRIPE_HASH_LOCKS - 1; } err = md_allow_write(mddev); if (err) return err; + hash = conf->max_nr_stripes % NR_STRIPE_HASH_LOCKS; while (size > conf->max_nr_stripes) { - if (grow_one_stripe(conf)) + if (grow_one_stripe(conf, hash)) conf->max_nr_stripes++; else break; + hash = (hash + 1) % NR_STRIPE_HASH_LOCKS; } return 0; } @@ -5277,7 +5431,7 @@ static struct attribute_group raid5_attrs_group = { static int alloc_thread_groups(struct r5conf *conf, int cnt) { - int i, j; + int i, j, k; ssize_t size; struct r5worker *workers; @@ -5307,8 +5461,12 @@ static int alloc_thread_groups(struct r5conf *conf, int cnt) group->workers = workers + i * cnt; for (j = 0; j < cnt; j++) { - group->workers[j].group = group; - INIT_WORK(&group->workers[j].work, raid5_do_work); + struct r5worker *worker = group->workers + j; + worker->group = group; + INIT_WORK(&worker->work, raid5_do_work); + + for (k = 0; k < NR_STRIPE_HASH_LOCKS; k++) + INIT_LIST_HEAD(worker->temp_inactive_list + k); } } @@ -5459,6 +5617,7 @@ static struct r5conf *setup_conf(struct mddev *mddev) struct md_rdev *rdev; struct disk_info *disk; char pers_name[6]; + int i; if (mddev->new_level != 5 && mddev->new_level != 4 @@ -5503,7 +5662,6 @@ static struct r5conf *setup_conf(struct mddev *mddev) INIT_LIST_HEAD(&conf->hold_list); INIT_LIST_HEAD(&conf->delayed_list); INIT_LIST_HEAD(&conf->bitmap_list); - INIT_LIST_HEAD(&conf->inactive_list); init_llist_head(&conf->released_stripes); atomic_set(&conf->active_stripes, 0); atomic_set(&conf->preread_active_stripes, 0); @@ -5529,6 +5687,21 @@ static struct r5conf *setup_conf(struct mddev *mddev) if ((conf->stripe_hashtbl = kzalloc(PAGE_SIZE, GFP_KERNEL)) == NULL) goto abort; + /* We init hash_locks[0] separately to that it can be used + * as the reference lock in the spin_lock_nest_lock() call + * in lock_all_device_hash_locks_irq in order to convince + * lockdep that we know what we are doing. + */ + spin_lock_init(conf->hash_locks); + for (i = 1; i < NR_STRIPE_HASH_LOCKS; i++) + spin_lock_init(conf->hash_locks + i); + + for (i = 0; i < NR_STRIPE_HASH_LOCKS; i++) + INIT_LIST_HEAD(conf->inactive_list + i); + + for (i = 0; i < NR_STRIPE_HASH_LOCKS; i++) + INIT_LIST_HEAD(conf->temp_inactive_list + i); + conf->level = mddev->new_level; if (raid5_alloc_percpu(conf) != 0) goto abort; @@ -5569,7 +5742,6 @@ static struct r5conf *setup_conf(struct mddev *mddev) else conf->max_degraded = 1; conf->algorithm = mddev->new_layout; - conf->max_nr_stripes = NR_STRIPES; conf->reshape_progress = mddev->reshape_position; if (conf->reshape_progress != MaxSector) { conf->prev_chunk_sectors = mddev->chunk_sectors; @@ -5578,7 +5750,7 @@ static struct r5conf *setup_conf(struct mddev *mddev) memory = conf->max_nr_stripes * (sizeof(struct stripe_head) + max_disks * ((sizeof(struct bio) + PAGE_SIZE))) / 1024; - if (grow_stripes(conf, conf->max_nr_stripes)) { + if (grow_stripes(conf, NR_STRIPES)) { printk(KERN_ERR "md/raid:%s: couldn't allocate %dkB for buffers\n", mdname(mddev), memory); @@ -6483,27 +6655,28 @@ static void raid5_quiesce(struct mddev *mddev, int state) break; case 1: /* stop all writes */ - spin_lock_irq(&conf->device_lock); + lock_all_device_hash_locks_irq(conf); /* '2' tells resync/reshape to pause so that all * active stripes can drain */ conf->quiesce = 2; - wait_event_lock_irq(conf->wait_for_stripe, + wait_event_cmd(conf->wait_for_stripe, atomic_read(&conf->active_stripes) == 0 && atomic_read(&conf->active_aligned_reads) == 0, - conf->device_lock); + unlock_all_device_hash_locks_irq(conf), + lock_all_device_hash_locks_irq(conf)); conf->quiesce = 1; - spin_unlock_irq(&conf->device_lock); + unlock_all_device_hash_locks_irq(conf); /* allow reshape to continue */ wake_up(&conf->wait_for_overlap); break; case 0: /* re-enable writes */ - spin_lock_irq(&conf->device_lock); + lock_all_device_hash_locks_irq(conf); conf->quiesce = 0; wake_up(&conf->wait_for_stripe); wake_up(&conf->wait_for_overlap); - spin_unlock_irq(&conf->device_lock); + unlock_all_device_hash_locks_irq(conf); break; } } diff --git a/drivers/md/raid5.h b/drivers/md/raid5.h index 2113ffa..a9e443a 100644 --- a/drivers/md/raid5.h +++ b/drivers/md/raid5.h @@ -205,6 +205,7 @@ struct stripe_head { short pd_idx; /* parity disk index */ short qd_idx; /* 'Q' disk index for raid6 */ short ddf_layout;/* use DDF ordering to calculate Q */ + short hash_lock_index; unsigned long state; /* state flags */ atomic_t count; /* nr of active thread/requests */ int bm_seq; /* sequence number for bitmap flushes */ @@ -367,9 +368,18 @@ struct disk_info { struct md_rdev *rdev, *replacement; }; +/* NOTE NR_STRIPE_HASH_LOCKS must remain below 64. + * This is because we sometimes take all the spinlocks + * and creating that much locking depth can cause + * problems. + */ +#define NR_STRIPE_HASH_LOCKS 8 +#define STRIPE_HASH_LOCKS_MASK (NR_STRIPE_HASH_LOCKS - 1) + struct r5worker { struct work_struct work; struct r5worker_group *group; + struct list_head temp_inactive_list[NR_STRIPE_HASH_LOCKS]; bool working; }; @@ -382,6 +392,8 @@ struct r5worker_group { struct r5conf { struct hlist_head *stripe_hashtbl; + /* only protect corresponding hash list and inactive_list */ + spinlock_t hash_locks[NR_STRIPE_HASH_LOCKS]; struct mddev *mddev; int chunk_sectors; int level, algorithm; @@ -462,7 +474,7 @@ struct r5conf { * Free stripes pool */ atomic_t active_stripes; - struct list_head inactive_list; + struct list_head inactive_list[NR_STRIPE_HASH_LOCKS]; struct llist_head released_stripes; wait_queue_head_t wait_for_stripe; wait_queue_head_t wait_for_overlap; @@ -477,6 +489,7 @@ struct r5conf { * the new thread here until we fully activate the array. */ struct md_thread *thread; + struct list_head temp_inactive_list[NR_STRIPE_HASH_LOCKS]; struct r5worker_group *worker_groups; int group_cnt; int worker_cnt_per_group; -- cgit v0.10.2 From 4bda556aea1d2916260326c6afa77b84a1f1345a Mon Sep 17 00:00:00 2001 From: Shaohua Li Date: Thu, 14 Nov 2013 15:16:17 +1100 Subject: raid5: relieve lock contention in get_active_stripe() track empty inactive list count, so md_raid5_congested() can use it to make decision. Signed-off-by: Shaohua Li Signed-off-by: NeilBrown diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c index 93090b2..1fb28c5 100644 --- a/drivers/md/raid5.c +++ b/drivers/md/raid5.c @@ -356,6 +356,9 @@ static void release_inactive_stripe_list(struct r5conf *conf, */ if (!list_empty_careful(list)) { spin_lock_irqsave(conf->hash_locks + hash, flags); + if (list_empty(conf->inactive_list + hash) && + !list_empty(list)) + atomic_dec(&conf->empty_inactive_list_nr); list_splice_tail_init(list, conf->inactive_list + hash); do_wakeup = true; spin_unlock_irqrestore(conf->hash_locks + hash, flags); @@ -477,6 +480,8 @@ static struct stripe_head *get_free_stripe(struct r5conf *conf, int hash) remove_hash(sh); atomic_inc(&conf->active_stripes); BUG_ON(hash != sh->hash_lock_index); + if (list_empty(conf->inactive_list + hash)) + atomic_inc(&conf->empty_inactive_list_nr); out: return sh; } @@ -4059,7 +4064,7 @@ int md_raid5_congested(struct mddev *mddev, int bits) return 1; if (conf->quiesce) return 1; - if (atomic_read(&conf->active_stripes) == conf->max_nr_stripes) + if (atomic_read(&conf->empty_inactive_list_nr)) return 1; return 0; @@ -5750,6 +5755,7 @@ static struct r5conf *setup_conf(struct mddev *mddev) memory = conf->max_nr_stripes * (sizeof(struct stripe_head) + max_disks * ((sizeof(struct bio) + PAGE_SIZE))) / 1024; + atomic_set(&conf->empty_inactive_list_nr, NR_STRIPE_HASH_LOCKS); if (grow_stripes(conf, NR_STRIPES)) { printk(KERN_ERR "md/raid:%s: couldn't allocate %dkB for buffers\n", diff --git a/drivers/md/raid5.h b/drivers/md/raid5.h index a9e443a..e440738 100644 --- a/drivers/md/raid5.h +++ b/drivers/md/raid5.h @@ -475,6 +475,7 @@ struct r5conf { */ atomic_t active_stripes; struct list_head inactive_list[NR_STRIPE_HASH_LOCKS]; + atomic_t empty_inactive_list_nr; struct llist_head released_stripes; wait_queue_head_t wait_for_stripe; wait_queue_head_t wait_for_overlap; -- cgit v0.10.2 From edfa1f651e93261eecb034d02284ece103dd691a Mon Sep 17 00:00:00 2001 From: Bian Yu Date: Thu, 14 Nov 2013 15:16:17 +1100 Subject: raid5: Retry R5_ReadNoMerge flag when hit a read error. Because of block layer merge, one bio fails will cause other bios which belongs to the same request fails, so raid5_end_read_request will record all these bios as badblocks. If retry request with R5_ReadNoMerge flag to avoid bios merge, badblocks can only record sector which is bad exactly. test: hdparm --yes-i-know-what-i-am-doing --make-bad-sector 300000 /dev/sdb mdadm -C /dev/md0 -l5 -n3 /dev/sd[bcd] --assume-clean mdadm /dev/md0 -f /dev/sdd mdadm /dev/md0 -r /dev/sdd mdadm --zero-superblock /dev/sdd mdadm /dev/md0 -a /dev/sdd 1. Without this patch: cat /sys/block/md0/md/rd*/bad_blocks 299776 256 299776 256 2. With this patch: cat /sys/block/md0/md/rd*/bad_blocks 300000 8 300000 8 Signed-off-by: Bian Yu Signed-off-by: NeilBrown diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c index 1fb28c5..2c89077 100644 --- a/drivers/md/raid5.c +++ b/drivers/md/raid5.c @@ -2056,6 +2056,9 @@ static void raid5_end_read_request(struct bio * bi, int error) mdname(conf->mddev), bdn); else retry = 1; + if (set_bad && test_bit(In_sync, &rdev->flags) + && !test_bit(R5_ReadNoMerge, &sh->dev[i].flags)) + retry = 1; if (retry) if (test_bit(R5_ReadNoMerge, &sh->dev[i].flags)) { set_bit(R5_ReadError, &sh->dev[i].flags); -- cgit v0.10.2 From 29f097c4d968021ee4fad1b033be5825ff78330e Mon Sep 17 00:00:00 2001 From: NeilBrown Date: Thu, 14 Nov 2013 17:54:51 +1100 Subject: md: fix some places where mddev_lock return value is not checked. Sometimes we need to lock and mddev and cannot cope with failure due to interrupt. In these cases we should use mutex_lock, not mutex_lock_interruptible. Signed-off-by: NeilBrown diff --git a/drivers/md/md.c b/drivers/md/md.c index 1975c2d..1ca47b0 100644 --- a/drivers/md/md.c +++ b/drivers/md/md.c @@ -602,11 +602,19 @@ static struct mddev * mddev_find(dev_t unit) goto retry; } -static inline int mddev_lock(struct mddev * mddev) +static inline int __must_check mddev_lock(struct mddev * mddev) { return mutex_lock_interruptible(&mddev->reconfig_mutex); } +/* Sometimes we need to take the lock in a situation where + * failure due to interrupts is not acceptable. + */ +static inline void mddev_lock_nointr(struct mddev * mddev) +{ + mutex_lock(&mddev->reconfig_mutex); +} + static inline int mddev_is_locked(struct mddev *mddev) { return mutex_is_locked(&mddev->reconfig_mutex); @@ -3018,7 +3026,7 @@ rdev_size_store(struct md_rdev *rdev, const char *buf, size_t len) for_each_mddev(mddev, tmp) { struct md_rdev *rdev2; - mddev_lock(mddev); + mddev_lock_nointr(mddev); rdev_for_each(rdev2, mddev) if (rdev->bdev == rdev2->bdev && rdev != rdev2 && @@ -3034,7 +3042,7 @@ rdev_size_store(struct md_rdev *rdev, const char *buf, size_t len) break; } } - mddev_lock(my_mddev); + mddev_lock_nointr(my_mddev); if (overlap) { /* Someone else could have slipped in a size * change here, but doing so is just silly. @@ -5299,7 +5307,7 @@ static void __md_stop_writes(struct mddev *mddev) void md_stop_writes(struct mddev *mddev) { - mddev_lock(mddev); + mddev_lock_nointr(mddev); __md_stop_writes(mddev); mddev_unlock(mddev); } @@ -6592,7 +6600,7 @@ static int md_ioctl(struct block_device *bdev, fmode_t mode, wait_event(mddev->sb_wait, !test_bit(MD_CHANGE_DEVS, &mddev->flags) && !test_bit(MD_CHANGE_PENDING, &mddev->flags)); - mddev_lock(mddev); + mddev_lock_nointr(mddev); } } else { err = -EROFS; -- cgit v0.10.2 From c91abf5a3546a4ff0838d2905f4d7eae2795f724 Mon Sep 17 00:00:00 2001 From: NeilBrown Date: Tue, 19 Nov 2013 12:02:01 +1100 Subject: md: use MD_RECOVERY_INTR instead of kthread_should_stop in resync thread. We currently use kthread_should_stop() in various places in the sync/reshape code to abort early. However some places set MD_RECOVERY_INTR but don't immediately call md_reap_sync_thread() (and we will shortly get another one). When this happens we are relying on md_check_recovery() to reap the thread and that only happen when it finishes normally. So MD_RECOVERY_INTR must lead to a normal finish without the kthread_should_stop() test. So replace all relevant tests, and be more careful when the thread is interrupted not to acknowledge that latest step in a reshape as it may not be fully committed yet. Also add a test on MD_RECOVERY_INTR in the 'is_mddev_idle' loop so we don't wait have to wait for the speed to drop before we can abort. Signed-off-by: NeilBrown diff --git a/drivers/md/md.c b/drivers/md/md.c index 1ca47b0..a74045d 100644 --- a/drivers/md/md.c +++ b/drivers/md/md.c @@ -7410,9 +7410,6 @@ void md_do_sync(struct md_thread *thread) mddev->curr_resync = 2; try_again: - if (kthread_should_stop()) - set_bit(MD_RECOVERY_INTR, &mddev->recovery); - if (test_bit(MD_RECOVERY_INTR, &mddev->recovery)) goto skip; for_each_mddev(mddev2, tmp) { @@ -7437,7 +7434,7 @@ void md_do_sync(struct md_thread *thread) * be caught by 'softlockup' */ prepare_to_wait(&resync_wait, &wq, TASK_INTERRUPTIBLE); - if (!kthread_should_stop() && + if (!test_bit(MD_RECOVERY_INTR, &mddev->recovery) && mddev2->curr_resync >= mddev->curr_resync) { printk(KERN_INFO "md: delaying %s of %s" " until %s has finished (they" @@ -7513,7 +7510,7 @@ void md_do_sync(struct md_thread *thread) last_check = 0; if (j>2) { - printk(KERN_INFO + printk(KERN_INFO "md: resuming %s of %s from checkpoint.\n", desc, mdname(mddev)); mddev->curr_resync = j; @@ -7550,7 +7547,8 @@ void md_do_sync(struct md_thread *thread) sysfs_notify(&mddev->kobj, NULL, "sync_completed"); } - while (j >= mddev->resync_max && !kthread_should_stop()) { + while (j >= mddev->resync_max && + !test_bit(MD_RECOVERY_INTR, &mddev->recovery)) { /* As this condition is controlled by user-space, * we can block indefinitely, so use '_interruptible' * to avoid triggering warnings. @@ -7558,17 +7556,18 @@ void md_do_sync(struct md_thread *thread) flush_signals(current); /* just in case */ wait_event_interruptible(mddev->recovery_wait, mddev->resync_max > j - || kthread_should_stop()); + || test_bit(MD_RECOVERY_INTR, + &mddev->recovery)); } - if (kthread_should_stop()) - goto interrupted; + if (test_bit(MD_RECOVERY_INTR, &mddev->recovery)) + break; sectors = mddev->pers->sync_request(mddev, j, &skipped, currspeed < speed_min(mddev)); if (sectors == 0) { set_bit(MD_RECOVERY_INTR, &mddev->recovery); - goto out; + break; } if (!skipped) { /* actual IO requested */ @@ -7605,10 +7604,8 @@ void md_do_sync(struct md_thread *thread) last_mark = next; } - - if (kthread_should_stop()) - goto interrupted; - + if (test_bit(MD_RECOVERY_INTR, &mddev->recovery)) + break; /* * this loop exits only if either when we are slower than @@ -7631,11 +7628,12 @@ void md_do_sync(struct md_thread *thread) } } } - printk(KERN_INFO "md: %s: %s done.\n",mdname(mddev), desc); + printk(KERN_INFO "md: %s: %s %s.\n",mdname(mddev), desc, + test_bit(MD_RECOVERY_INTR, &mddev->recovery) + ? "interrupted" : "done"); /* * this also signals 'finished resyncing' to md_stop */ - out: blk_finish_plug(&plug); wait_event(mddev->recovery_wait, !atomic_read(&mddev->recovery_active)); @@ -7689,16 +7687,6 @@ void md_do_sync(struct md_thread *thread) set_bit(MD_RECOVERY_DONE, &mddev->recovery); md_wakeup_thread(mddev->thread); return; - - interrupted: - /* - * got a signal, exit. - */ - printk(KERN_INFO - "md: md_do_sync() got signal ... exiting\n"); - set_bit(MD_RECOVERY_INTR, &mddev->recovery); - goto out; - } EXPORT_SYMBOL_GPL(md_do_sync); diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c index 73dc8a3..4f87ba5 100644 --- a/drivers/md/raid10.c +++ b/drivers/md/raid10.c @@ -4386,7 +4386,11 @@ static sector_t reshape_request(struct mddev *mddev, sector_t sector_nr, set_bit(MD_CHANGE_DEVS, &mddev->flags); md_wakeup_thread(mddev->thread); wait_event(mddev->sb_wait, mddev->flags == 0 || - kthread_should_stop()); + test_bit(MD_RECOVERY_INTR, &mddev->recovery)); + if (test_bit(MD_RECOVERY_INTR, &mddev->recovery)) { + allow_barrier(conf); + return sectors_done; + } conf->reshape_safe = mddev->reshape_position; allow_barrier(conf); } diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c index 2c89077..02f6bc2 100644 --- a/drivers/md/raid5.c +++ b/drivers/md/raid5.c @@ -4842,14 +4842,19 @@ static sector_t reshape_request(struct mddev *mddev, sector_t sector_nr, int *sk time_after(jiffies, conf->reshape_checkpoint + 10*HZ)) { /* Cannot proceed until we've updated the superblock... */ wait_event(conf->wait_for_overlap, - atomic_read(&conf->reshape_stripes)==0); + atomic_read(&conf->reshape_stripes)==0 + || test_bit(MD_RECOVERY_INTR, &mddev->recovery)); + if (atomic_read(&conf->reshape_stripes) != 0) + return 0; mddev->reshape_position = conf->reshape_progress; mddev->curr_resync_completed = sector_nr; conf->reshape_checkpoint = jiffies; set_bit(MD_CHANGE_DEVS, &mddev->flags); md_wakeup_thread(mddev->thread); wait_event(mddev->sb_wait, mddev->flags == 0 || - kthread_should_stop()); + test_bit(MD_RECOVERY_INTR, &mddev->recovery)); + if (test_bit(MD_RECOVERY_INTR, &mddev->recovery)) + return 0; spin_lock_irq(&conf->device_lock); conf->reshape_safe = mddev->reshape_position; spin_unlock_irq(&conf->device_lock); @@ -4932,7 +4937,10 @@ static sector_t reshape_request(struct mddev *mddev, sector_t sector_nr, int *sk >= mddev->resync_max - mddev->curr_resync_completed) { /* Cannot proceed until we've updated the superblock... */ wait_event(conf->wait_for_overlap, - atomic_read(&conf->reshape_stripes) == 0); + atomic_read(&conf->reshape_stripes) == 0 + || test_bit(MD_RECOVERY_INTR, &mddev->recovery)); + if (atomic_read(&conf->reshape_stripes) != 0) + goto ret; mddev->reshape_position = conf->reshape_progress; mddev->curr_resync_completed = sector_nr; conf->reshape_checkpoint = jiffies; @@ -4940,13 +4948,16 @@ static sector_t reshape_request(struct mddev *mddev, sector_t sector_nr, int *sk md_wakeup_thread(mddev->thread); wait_event(mddev->sb_wait, !test_bit(MD_CHANGE_DEVS, &mddev->flags) - || kthread_should_stop()); + || test_bit(MD_RECOVERY_INTR, &mddev->recovery)); + if (test_bit(MD_RECOVERY_INTR, &mddev->recovery)) + goto ret; spin_lock_irq(&conf->device_lock); conf->reshape_safe = mddev->reshape_position; spin_unlock_irq(&conf->device_lock); wake_up(&conf->wait_for_overlap); sysfs_notify(&mddev->kobj, NULL, "sync_completed"); } +ret: return reshape_sectors; } -- cgit v0.10.2 From 30b8feb730f9b9b3c5de02580897da03f59b6b16 Mon Sep 17 00:00:00 2001 From: NeilBrown Date: Thu, 14 Nov 2013 15:16:17 +1100 Subject: md/raid5: avoid deadlock when raid5 array has unack badblocks during md_stop_writes. When raid5 recovery hits a fresh badblock, this badblock will flagged as unack badblock until md_update_sb() is called. But md_stop will take reconfig lock which means raid5d can't call md_update_sb() in md_check_recovery(), the badblock will always be unack, so raid5d thread enters an infinite loop and md_stop_write() can never stop sync_thread. This causes deadlock. To solve this, when STOP_ARRAY ioctl is issued and sync_thread is running, we need set md->recovery FROZEN and INTR flags and wait for sync_thread to stop before we (re)take reconfig lock. This requires that raid5 reshape_request notices MD_RECOVERY_INTR (which it probably should have noticed anyway) and stops waiting for a metadata update in that case. Reported-by: Jianpeng Ma Reported-by: Bian Yu Signed-off-by: NeilBrown diff --git a/drivers/md/md.c b/drivers/md/md.c index a74045d..47e7bc7 100644 --- a/drivers/md/md.c +++ b/drivers/md/md.c @@ -5340,20 +5340,35 @@ EXPORT_SYMBOL_GPL(md_stop); static int md_set_readonly(struct mddev *mddev, struct block_device *bdev) { int err = 0; + int did_freeze = 0; + + if (!test_bit(MD_RECOVERY_FROZEN, &mddev->recovery)) { + did_freeze = 1; + set_bit(MD_RECOVERY_FROZEN, &mddev->recovery); + md_wakeup_thread(mddev->thread); + } + if (mddev->sync_thread) { + set_bit(MD_RECOVERY_INTR, &mddev->recovery); + /* Thread might be blocked waiting for metadata update + * which will now never happen */ + wake_up_process(mddev->sync_thread->tsk); + } + mddev_unlock(mddev); + wait_event(resync_wait, mddev->sync_thread == NULL); + mddev_lock_nointr(mddev); + mutex_lock(&mddev->open_mutex); - if (atomic_read(&mddev->openers) > !!bdev) { + if (atomic_read(&mddev->openers) > !!bdev || + mddev->sync_thread || + (bdev && !test_bit(MD_STILL_CLOSED, &mddev->flags))) { printk("md: %s still in use.\n",mdname(mddev)); + if (did_freeze) { + clear_bit(MD_RECOVERY_FROZEN, &mddev->recovery); + md_wakeup_thread(mddev->thread); + } err = -EBUSY; goto out; } - if (bdev && !test_bit(MD_STILL_CLOSED, &mddev->flags)) { - /* Someone opened the device since we flushed it - * so page cache could be dirty and it is too late - * to flush. So abort - */ - mutex_unlock(&mddev->open_mutex); - return -EBUSY; - } if (mddev->pers) { __md_stop_writes(mddev); @@ -5364,7 +5379,7 @@ static int md_set_readonly(struct mddev *mddev, struct block_device *bdev) set_disk_ro(mddev->gendisk, 1); clear_bit(MD_RECOVERY_FROZEN, &mddev->recovery); sysfs_notify_dirent_safe(mddev->sysfs_state); - err = 0; + err = 0; } out: mutex_unlock(&mddev->open_mutex); @@ -5380,20 +5395,34 @@ static int do_md_stop(struct mddev * mddev, int mode, { struct gendisk *disk = mddev->gendisk; struct md_rdev *rdev; + int did_freeze = 0; + + if (!test_bit(MD_RECOVERY_FROZEN, &mddev->recovery)) { + did_freeze = 1; + set_bit(MD_RECOVERY_FROZEN, &mddev->recovery); + md_wakeup_thread(mddev->thread); + } + if (mddev->sync_thread) { + set_bit(MD_RECOVERY_INTR, &mddev->recovery); + /* Thread might be blocked waiting for metadata update + * which will now never happen */ + wake_up_process(mddev->sync_thread->tsk); + } + mddev_unlock(mddev); + wait_event(resync_wait, mddev->sync_thread == NULL); + mddev_lock_nointr(mddev); mutex_lock(&mddev->open_mutex); if (atomic_read(&mddev->openers) > !!bdev || - mddev->sysfs_active) { + mddev->sysfs_active || + mddev->sync_thread || + (bdev && !test_bit(MD_STILL_CLOSED, &mddev->flags))) { printk("md: %s still in use.\n",mdname(mddev)); mutex_unlock(&mddev->open_mutex); - return -EBUSY; - } - if (bdev && !test_bit(MD_STILL_CLOSED, &mddev->flags)) { - /* Someone opened the device since we flushed it - * so page cache could be dirty and it is too late - * to flush. So abort - */ - mutex_unlock(&mddev->open_mutex); + if (did_freeze) { + clear_bit(MD_RECOVERY_FROZEN, &mddev->recovery); + md_wakeup_thread(mddev->thread); + } return -EBUSY; } if (mddev->pers) { @@ -7931,6 +7960,7 @@ void md_reap_sync_thread(struct mddev *mddev) /* resync has finished, collect result */ md_unregister_thread(&mddev->sync_thread); + wake_up(&resync_wait); if (!test_bit(MD_RECOVERY_INTR, &mddev->recovery) && !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery)) { /* success...*/ -- cgit v0.10.2 From 82592c38a85889fc9b52bf67afd4f6a336858a96 Mon Sep 17 00:00:00 2001 From: Joe Perches Date: Thu, 14 Nov 2013 15:16:18 +1100 Subject: md: Convert use of typedef ctl_table to struct ctl_table This typedef is unnecessary and should just be removed. Signed-off-by: Joe Perches Signed-off-by: NeilBrown diff --git a/drivers/md/md.c b/drivers/md/md.c index 47e7bc7..84fbc5b 100644 --- a/drivers/md/md.c +++ b/drivers/md/md.c @@ -112,7 +112,7 @@ static inline int speed_max(struct mddev *mddev) static struct ctl_table_header *raid_table_header; -static ctl_table raid_table[] = { +static struct ctl_table raid_table[] = { { .procname = "speed_limit_min", .data = &sysctl_speed_limit_min, @@ -130,7 +130,7 @@ static ctl_table raid_table[] = { { } }; -static ctl_table raid_dir_table[] = { +static struct ctl_table raid_dir_table[] = { { .procname = "raid", .maxlen = 0, @@ -140,7 +140,7 @@ static ctl_table raid_dir_table[] = { { } }; -static ctl_table raid_root_table[] = { +static struct ctl_table raid_root_table[] = { { .procname = "dev", .maxlen = 0, -- cgit v0.10.2 From b364e3d048e49b1d177eb7ee7853e77aa0560464 Mon Sep 17 00:00:00 2001 From: majianpeng Date: Thu, 14 Nov 2013 15:16:18 +1100 Subject: raid1: Add a field array_frozen to indicate whether raid in freeze state. Because the following patch will rewrite the content between normal IO and resync IO. So we used a parameter to indicate whether raid is in freeze array. Signed-off-by: Jianpeng Ma Signed-off-by: NeilBrown diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c index aacf6bf..729db21 100644 --- a/drivers/md/raid1.c +++ b/drivers/md/raid1.c @@ -829,6 +829,7 @@ static void raise_barrier(struct r1conf *conf) /* Now wait for all pending IO to complete */ wait_event_lock_irq(conf->wait_barrier, + !conf->array_frozen && !conf->nr_pending && conf->barrier < RESYNC_DEPTH, conf->resync_lock); @@ -860,10 +861,11 @@ static void wait_barrier(struct r1conf *conf) * count down. */ wait_event_lock_irq(conf->wait_barrier, - !conf->barrier || + !conf->array_frozen && + (!conf->barrier || (conf->nr_pending && current->bio_list && - !bio_list_empty(current->bio_list)), + !bio_list_empty(current->bio_list))), conf->resync_lock); conf->nr_waiting--; } @@ -884,8 +886,7 @@ static void freeze_array(struct r1conf *conf, int extra) { /* stop syncio and normal IO and wait for everything to * go quite. - * We increment barrier and nr_waiting, and then - * wait until nr_pending match nr_queued+extra + * We wait until nr_pending match nr_queued+extra * This is called in the context of one normal IO request * that has failed. Thus any sync request that might be pending * will be blocked by nr_pending, and we need to wait for @@ -895,8 +896,7 @@ static void freeze_array(struct r1conf *conf, int extra) * we continue. */ spin_lock_irq(&conf->resync_lock); - conf->barrier++; - conf->nr_waiting++; + conf->array_frozen = 1; wait_event_lock_irq_cmd(conf->wait_barrier, conf->nr_pending == conf->nr_queued+extra, conf->resync_lock, @@ -907,8 +907,7 @@ static void unfreeze_array(struct r1conf *conf) { /* reverse the effect of the freeze */ spin_lock_irq(&conf->resync_lock); - conf->barrier--; - conf->nr_waiting--; + conf->array_frozen = 0; wake_up(&conf->wait_barrier); spin_unlock_irq(&conf->resync_lock); } diff --git a/drivers/md/raid1.h b/drivers/md/raid1.h index 0ff3715..331a98a 100644 --- a/drivers/md/raid1.h +++ b/drivers/md/raid1.h @@ -65,6 +65,7 @@ struct r1conf { int nr_waiting; int nr_queued; int barrier; + int array_frozen; /* Set to 1 if a full sync is needed, (fresh device added). * Cleared when a sync completes. -- cgit v0.10.2 From 07169fd478ed2fbb3c894d524be9400658f16747 Mon Sep 17 00:00:00 2001 From: majianpeng Date: Thu, 14 Nov 2013 15:16:18 +1100 Subject: raid1: Replace raise_barrier/lower_barrier with freeze_array/unfreeze_array when reconfiguring the array. We used to use raise_barrier to suspend normal IO while we reconfigure the array. However raise_barrier will soon only suspend some normal IO, not all. So we need something else. Change it to use freeze_array. But freeze_array not only suspends normal io, it also suspends resync io. For the place where call raise_barrier for reconfigure, it isn't a problem. Signed-off-by: Jianpeng Ma Signed-off-by: NeilBrown diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c index 729db21..ba5efb0 100644 --- a/drivers/md/raid1.c +++ b/drivers/md/raid1.c @@ -2870,8 +2870,8 @@ static int stop(struct mddev *mddev) atomic_read(&bitmap->behind_writes) == 0); } - raise_barrier(conf); - lower_barrier(conf); + freeze_array(conf, 0); + unfreeze_array(conf); md_unregister_thread(&mddev->thread); if (conf->r1bio_pool) @@ -3030,10 +3030,10 @@ static void raid1_quiesce(struct mddev *mddev, int state) wake_up(&conf->wait_barrier); break; case 1: - raise_barrier(conf); + freeze_array(conf, 0); break; case 0: - lower_barrier(conf); + unfreeze_array(conf); break; } } @@ -3050,7 +3050,8 @@ static void *raid1_takeover(struct mddev *mddev) mddev->new_chunk_sectors = 0; conf = setup_conf(mddev); if (!IS_ERR(conf)) - conf->barrier = 1; + /* Array must appear to be quiesced */ + conf->array_frozen = 1; return conf; } return ERR_PTR(-EINVAL); -- cgit v0.10.2 From 8e005f7c0276317cfa8fcb0291a0df57f9ef832c Mon Sep 17 00:00:00 2001 From: majianpeng Date: Thu, 14 Nov 2013 15:16:18 +1100 Subject: raid1: Add some macros to make code clearly. In a subsequent patch, we'll use some const parameters. Using macros will make the code clearly. Signed-off-by: Jianpeng Ma Signed-off-by: NeilBrown diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c index ba5efb0..78da339 100644 --- a/drivers/md/raid1.c +++ b/drivers/md/raid1.c @@ -84,10 +84,12 @@ static void r1bio_pool_free(void *r1_bio, void *data) } #define RESYNC_BLOCK_SIZE (64*1024) -//#define RESYNC_BLOCK_SIZE PAGE_SIZE +#define RESYNC_DEPTH 32 #define RESYNC_SECTORS (RESYNC_BLOCK_SIZE >> 9) #define RESYNC_PAGES ((RESYNC_BLOCK_SIZE + PAGE_SIZE-1) / PAGE_SIZE) -#define RESYNC_WINDOW (2048*1024) +#define RESYNC_WINDOW (RESYNC_BLOCK_SIZE * RESYNC_DEPTH) +#define RESYNC_WINDOW_SECTORS (RESYNC_WINDOW >> 9) +#define NEXT_NORMALIO_DISTANCE (3 * RESYNC_WINDOW_SECTORS) static void * r1buf_pool_alloc(gfp_t gfp_flags, void *data) { @@ -814,8 +816,6 @@ static void flush_pending_writes(struct r1conf *conf) * there is no normal IO happeing. It must arrange to call * lower_barrier when the particular background IO completes. */ -#define RESYNC_DEPTH 32 - static void raise_barrier(struct r1conf *conf) { spin_lock_irq(&conf->resync_lock); -- cgit v0.10.2 From 79ef3a8aa1cb1523cc231c9a90a278333c21f761 Mon Sep 17 00:00:00 2001 From: majianpeng Date: Fri, 15 Nov 2013 14:55:02 +0800 Subject: raid1: Rewrite the implementation of iobarrier. There is an iobarrier in raid1 because of contention between normal IO and resync IO. It suspends all normal IO when resync/recovery happens. However if normal IO is out side the resync window, there is no contention. So this patch changes the barrier mechanism to only block IO that could contend with the resync that is currently happening. We partition the whole space into five parts. |---------|-----------|------------|----------------|-------| start next_resync start_next_window end_window start + RESYNC_WINDOW = next_resync next_resync + NEXT_NORMALIO_DISTANCE = start_next_window start_next_window + NEXT_NORMALIO_DISTANCE = end_window Firstly we introduce some concepts: 1 - RESYNC_WINDOW: For resync, there are 32 resync requests at most at the same time. A sync request is RESYNC_BLOCK_SIZE(64*1024). So the RESYNC_WINDOW is 32 * RESYNC_BLOCK_SIZE, that is 2MB. 2 - NEXT_NORMALIO_DISTANCE: the distance between next_resync and start_next_window. It also indicates the distance between start_next_window and end_window. It is currently 3 * RESYNC_WINDOW_SIZE but could be tuned if this turned out not to be optimal. 3 - next_resync: the next sector at which we will do sync IO. 4 - start: a position which is at most RESYNC_WINDOW before next_resync. 5 - start_next_window: a position which is NEXT_NORMALIO_DISTANCE beyond next_resync. Normal-io after this position doesn't need to wait for resync-io to complete. 6 - end_window: a position which is 2 * NEXT_NORMALIO_DISTANCE beyond next_resync. This also doesn't need to wait, but is counted differently. 7 - current_window_requests: the count of normalIO between start_next_window and end_window. 8 - next_window_requests: the count of normalIO after end_window. NormalIO will be partitioned into four types: NormIO1: the end sector of bio is smaller or equal the start NormIO2: the start sector of bio larger or equal to end_window NormIO3: the start sector of bio larger or equal to start_next_window. NormIO4: the location between start_next_window and end_window |--------|-----------|--------------------|----------------|-------------| | start | next_resync | start_next_window | end_window | NormIO1 NormIO4 NormIO4 NormIO3 NormIO2 For NormIO1, we don't need any io barrier. For NormIO4, we used a similar approach to the original iobarrier mechanism. The normalIO and resyncIO must be kept separate. For NormIO2/3, we add two fields to struct r1conf: "current_window_requests" and "next_window_requests". They indicate the count of active requests in the two window. For these, we don't wait for resync io to complete. For resync action, if there are NormIO4s, we must wait for it. If not, we can proceed. But if resync action reaches start_next_window and current_window_requests > 0 (that is there are NormIO3s), we must wait until the current_window_requests becomes zero. When current_window_requests becomes zero, start_next_window also moves forward. Then current_window_requests will replaced by next_window_requests. There is a problem which when and how to change from NormIO2 to NormIO3. Only then can sync action progress. We add a field in struct r1conf "start_next_window". A: if start_next_window == MaxSector, it means there are no NormIO2/3. So start_next_window = next_resync + NEXT_NORMALIO_DISTANCE B: if current_window_requests == 0 && next_window_requests != 0, it means start_next_window move to end_window There is another problem which how to differentiate between old NormIO2(now it is NormIO3) and NormIO2. For example, there are many bios which are NormIO2 and a bio which is NormIO3. NormIO3 firstly completed, so the bios of NormIO2 became NormIO3. We add a field in struct r1bio "start_next_window". This is used to record the position conf->start_next_window when the call to wait_barrier() is made in make_request(). In allow_barrier(), we check the conf->start_next_window. If r1bio->stat_next_window == conf->start_next_window, it means there is no transition between NormIO2 and NormIO3. If r1bio->start_next_window != conf->start_next_window, it mean there was a transition between NormIO2 and NormIO3. There can only have been one transition. So it only means the bio is old NormIO2. For one bio, there may be many r1bio's. So we make sure all the r1bio->start_next_window are the same value. If we met blocked_dev in make_request(), it must call allow_barrier and wait_barrier. So the former and the later value of conf->start_next_window will be change. If there are many r1bio's with differnet start_next_window, for the relevant bio, it depend on the last value of r1bio. It will cause error. To avoid this, we must wait for previous r1bios to complete. Signed-off-by: Jianpeng Ma Signed-off-by: NeilBrown diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c index 78da339..d9ee4ed 100644 --- a/drivers/md/raid1.c +++ b/drivers/md/raid1.c @@ -66,7 +66,8 @@ */ static int max_queued_requests = 1024; -static void allow_barrier(struct r1conf *conf); +static void allow_barrier(struct r1conf *conf, sector_t start_next_window, + sector_t bi_sector); static void lower_barrier(struct r1conf *conf); static void * r1bio_pool_alloc(gfp_t gfp_flags, void *data) @@ -227,6 +228,8 @@ static void call_bio_endio(struct r1bio *r1_bio) struct bio *bio = r1_bio->master_bio; int done; struct r1conf *conf = r1_bio->mddev->private; + sector_t start_next_window = r1_bio->start_next_window; + sector_t bi_sector = bio->bi_sector; if (bio->bi_phys_segments) { unsigned long flags; @@ -234,6 +237,11 @@ static void call_bio_endio(struct r1bio *r1_bio) bio->bi_phys_segments--; done = (bio->bi_phys_segments == 0); spin_unlock_irqrestore(&conf->device_lock, flags); + /* + * make_request() might be waiting for + * bi_phys_segments to decrease + */ + wake_up(&conf->wait_barrier); } else done = 1; @@ -245,7 +253,7 @@ static void call_bio_endio(struct r1bio *r1_bio) * Wake up any possible resync thread that waits for the device * to go idle. */ - allow_barrier(conf); + allow_barrier(conf, start_next_window, bi_sector); } } @@ -827,10 +835,19 @@ static void raise_barrier(struct r1conf *conf) /* block any new IO from starting */ conf->barrier++; - /* Now wait for all pending IO to complete */ + /* For these conditions we must wait: + * A: while the array is in frozen state + * B: while barrier >= RESYNC_DEPTH, meaning resync reach + * the max count which allowed. + * C: next_resync + RESYNC_SECTORS > start_next_window, meaning + * next resync will reach to the window which normal bios are + * handling. + */ wait_event_lock_irq(conf->wait_barrier, !conf->array_frozen && - !conf->nr_pending && conf->barrier < RESYNC_DEPTH, + conf->barrier < RESYNC_DEPTH && + (conf->start_next_window >= + conf->next_resync + RESYNC_SECTORS), conf->resync_lock); spin_unlock_irq(&conf->resync_lock); @@ -846,10 +863,33 @@ static void lower_barrier(struct r1conf *conf) wake_up(&conf->wait_barrier); } -static void wait_barrier(struct r1conf *conf) +static bool need_to_wait_for_sync(struct r1conf *conf, struct bio *bio) +{ + bool wait = false; + + if (conf->array_frozen || !bio) + wait = true; + else if (conf->barrier && bio_data_dir(bio) == WRITE) { + if (conf->next_resync < RESYNC_WINDOW_SECTORS) + wait = true; + else if ((conf->next_resync - RESYNC_WINDOW_SECTORS + >= bio_end_sector(bio)) || + (conf->next_resync + NEXT_NORMALIO_DISTANCE + <= bio->bi_sector)) + wait = false; + else + wait = true; + } + + return wait; +} + +static sector_t wait_barrier(struct r1conf *conf, struct bio *bio) { + sector_t sector = 0; + spin_lock_irq(&conf->resync_lock); - if (conf->barrier) { + if (need_to_wait_for_sync(conf, bio)) { conf->nr_waiting++; /* Wait for the barrier to drop. * However if there are already pending @@ -863,21 +903,65 @@ static void wait_barrier(struct r1conf *conf) wait_event_lock_irq(conf->wait_barrier, !conf->array_frozen && (!conf->barrier || - (conf->nr_pending && + ((conf->start_next_window < + conf->next_resync + RESYNC_SECTORS) && current->bio_list && !bio_list_empty(current->bio_list))), conf->resync_lock); conf->nr_waiting--; } + + if (bio && bio_data_dir(bio) == WRITE) { + if (conf->next_resync + NEXT_NORMALIO_DISTANCE + <= bio->bi_sector) { + if (conf->start_next_window == MaxSector) + conf->start_next_window = + conf->next_resync + + NEXT_NORMALIO_DISTANCE; + + if ((conf->start_next_window + NEXT_NORMALIO_DISTANCE) + <= bio->bi_sector) + conf->next_window_requests++; + else + conf->current_window_requests++; + } + if (bio->bi_sector >= conf->start_next_window) + sector = conf->start_next_window; + } + conf->nr_pending++; spin_unlock_irq(&conf->resync_lock); + return sector; } -static void allow_barrier(struct r1conf *conf) +static void allow_barrier(struct r1conf *conf, sector_t start_next_window, + sector_t bi_sector) { unsigned long flags; + spin_lock_irqsave(&conf->resync_lock, flags); conf->nr_pending--; + if (start_next_window) { + if (start_next_window == conf->start_next_window) { + if (conf->start_next_window + NEXT_NORMALIO_DISTANCE + <= bi_sector) + conf->next_window_requests--; + else + conf->current_window_requests--; + } else + conf->current_window_requests--; + + if (!conf->current_window_requests) { + if (conf->next_window_requests) { + conf->current_window_requests = + conf->next_window_requests; + conf->next_window_requests = 0; + conf->start_next_window += + NEXT_NORMALIO_DISTANCE; + } else + conf->start_next_window = MaxSector; + } + } spin_unlock_irqrestore(&conf->resync_lock, flags); wake_up(&conf->wait_barrier); } @@ -1012,6 +1096,7 @@ static void make_request(struct mddev *mddev, struct bio * bio) int first_clone; int sectors_handled; int max_sectors; + sector_t start_next_window; /* * Register the new request and wait if the reconstruction @@ -1041,7 +1126,7 @@ static void make_request(struct mddev *mddev, struct bio * bio) finish_wait(&conf->wait_barrier, &w); } - wait_barrier(conf); + start_next_window = wait_barrier(conf, bio); bitmap = mddev->bitmap; @@ -1162,6 +1247,7 @@ read_again: disks = conf->raid_disks * 2; retry_write: + r1_bio->start_next_window = start_next_window; blocked_rdev = NULL; rcu_read_lock(); max_sectors = r1_bio->sectors; @@ -1230,14 +1316,24 @@ read_again: if (unlikely(blocked_rdev)) { /* Wait for this device to become unblocked */ int j; + sector_t old = start_next_window; for (j = 0; j < i; j++) if (r1_bio->bios[j]) rdev_dec_pending(conf->mirrors[j].rdev, mddev); r1_bio->state = 0; - allow_barrier(conf); + allow_barrier(conf, start_next_window, bio->bi_sector); md_wait_for_blocked_rdev(blocked_rdev, mddev); - wait_barrier(conf); + start_next_window = wait_barrier(conf, bio); + /* + * We must make sure the multi r1bios of bio have + * the same value of bi_phys_segments + */ + if (bio->bi_phys_segments && old && + old != start_next_window) + /* Wait for the former r1bio(s) to complete */ + wait_event(conf->wait_barrier, + bio->bi_phys_segments == 1); goto retry_write; } @@ -1437,11 +1533,14 @@ static void print_conf(struct r1conf *conf) static void close_sync(struct r1conf *conf) { - wait_barrier(conf); - allow_barrier(conf); + wait_barrier(conf, NULL); + allow_barrier(conf, 0, 0); mempool_destroy(conf->r1buf_pool); conf->r1buf_pool = NULL; + + conf->next_resync = 0; + conf->start_next_window = MaxSector; } static int raid1_spare_active(struct mddev *mddev) @@ -2713,6 +2812,9 @@ static struct r1conf *setup_conf(struct mddev *mddev) conf->pending_count = 0; conf->recovery_disabled = mddev->recovery_disabled - 1; + conf->start_next_window = MaxSector; + conf->current_window_requests = conf->next_window_requests = 0; + err = -EIO; for (i = 0; i < conf->raid_disks * 2; i++) { diff --git a/drivers/md/raid1.h b/drivers/md/raid1.h index 331a98a..9bebca7 100644 --- a/drivers/md/raid1.h +++ b/drivers/md/raid1.h @@ -41,6 +41,19 @@ struct r1conf { */ sector_t next_resync; + /* When raid1 starts resync, we divide array into four partitions + * |---------|--------------|---------------------|-------------| + * next_resync start_next_window end_window + * start_next_window = next_resync + NEXT_NORMALIO_DISTANCE + * end_window = start_next_window + NEXT_NORMALIO_DISTANCE + * current_window_requests means the count of normalIO between + * start_next_window and end_window. + * next_window_requests means the count of normalIO after end_window. + * */ + sector_t start_next_window; + int current_window_requests; + int next_window_requests; + spinlock_t device_lock; /* list of 'struct r1bio' that need to be processed by raid1d, @@ -112,6 +125,7 @@ struct r1bio { * in this BehindIO request */ sector_t sector; + sector_t start_next_window; int sectors; unsigned long state; struct mddev *mddev; -- cgit v0.10.2 From c0f8bd146a8b3e630798561c605f5669823107af Mon Sep 17 00:00:00 2001 From: Aurelien Jarno Date: Thu, 14 Nov 2013 15:16:19 +1100 Subject: UAPI: include in linux/raid/md_p.h linux/raid/md_p.h is using conditionals depending on endianess and fails with an error if neither of __BIG_ENDIAN, __LITTLE_ENDIAN or __BYTE_ORDER are defined, but it doesn't include any header which can define these constants. This make this header unusable alone. This patch adds a #include at the beginning of this header to make it usable alone. This is needed to compile klibc on MIPS. Signed-off-by: Aurelien Jarno Signed-off-by: NeilBrown diff --git a/include/uapi/linux/raid/md_p.h b/include/uapi/linux/raid/md_p.h index fe1a540..f7cf7f3 100644 --- a/include/uapi/linux/raid/md_p.h +++ b/include/uapi/linux/raid/md_p.h @@ -16,6 +16,7 @@ #define _MD_P_H #include +#include /* * RAID superblock. -- cgit v0.10.2 From e59aa23f4c0c61b4baa5d535a2071d6666e83502 Mon Sep 17 00:00:00 2001 From: majianpeng Date: Thu, 14 Nov 2013 15:16:19 +1100 Subject: md/raid5: For stripe with R5_ReadNoMerge, we replace REQ_FLUSH with REQ_NOMERGE. For R5_ReadNoMerge,it mean this bio can't merge with other bios or request.It used REQ_FLUSH to achieve this. But REQ_NOMERGE can do the same work. Signed-off-by: Jianpeng Ma Signed-off-by: NeilBrown diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c index 02f6bc2..6c724fd 100644 --- a/drivers/md/raid5.c +++ b/drivers/md/raid5.c @@ -874,7 +874,7 @@ static void ops_run_io(struct stripe_head *sh, struct stripe_head_state *s) bi->bi_sector = (sh->sector + rdev->data_offset); if (test_bit(R5_ReadNoMerge, &sh->dev[i].flags)) - bi->bi_rw |= REQ_FLUSH; + bi->bi_rw |= REQ_NOMERGE; bi->bi_vcnt = 1; bi->bi_io_vec[0].bv_len = STRIPE_SIZE; -- cgit v0.10.2 From d206dcfa9809ec3409483e93b5e362f801fa0c27 Mon Sep 17 00:00:00 2001 From: majianpeng Date: Thu, 14 Nov 2013 15:16:19 +1100 Subject: md/raid5: Before freeing old multi-thread worker, it should flush them. When changing group_thread_cnt from sysfs entry, the kernel can oops. The kernel messages are: [ 740.961389] BUG: unable to handle kernel NULL pointer dereference at 0000000000000008 [ 740.961444] IP: [] process_one_work+0x30/0x500 [ 740.961476] PGD b9013067 PUD b651e067 PMD 0 [ 740.961503] Oops: 0000 [#1] SMP [ 740.961525] Modules linked in: netconsole e1000e ptp pps_core [ 740.961577] CPU: 0 PID: 3683 Comm: kworker/u8:5 Not tainted 3.12.0+ #23 [ 740.961602] Hardware name: To Be Filled By O.E.M. To Be Filled By O.E.M./To be filled by O.E.M., BIOS 080015 11/09/2011 [ 740.961646] task: ffff88013abe0000 ti: ffff88013a246000 task.ti: ffff88013a246000 [ 740.961673] RIP: 0010:[] [] process_one_work+0x30/0x500 [ 740.961708] RSP: 0018:ffff88013a247e08 EFLAGS: 00010086 [ 740.961730] RAX: ffff8800b912b400 RBX: ffff88013a61e680 RCX: ffff8800b912b400 [ 740.961757] RDX: ffff8800b912b600 RSI: ffff8800b912b600 RDI: ffff88013a61e680 [ 740.961782] RBP: ffff88013a247e48 R08: ffff88013a246000 R09: 000000000002c09d [ 740.961808] R10: 000000000000010f R11: 0000000000000000 R12: ffff88013b00cc00 [ 740.961833] R13: 0000000000000000 R14: ffff88013b00cf80 R15: ffff88013a61e6b0 [ 740.961861] FS: 0000000000000000(0000) GS:ffff88013fc00000(0000) knlGS:0000000000000000 [ 740.961893] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b [ 740.962001] CR2: 00000000000000b8 CR3: 00000000b24fe000 CR4: 00000000000407f0 [ 740.962001] Stack: [ 740.962001] 0000000000000008 ffff8800b912b600 ffff88013b00cc00 ffff88013a61e680 [ 740.962001] ffff88013b00cc00 ffff88013b00cc18 ffff88013b00cf80 ffff88013a61e6b0 [ 740.962001] ffff88013a247eb8 ffffffff810639c6 0000000000012a80 ffff88013a247fd8 [ 740.962001] Call Trace: [ 740.962001] [] worker_thread+0x206/0x3f0 [ 740.962001] [] ? manage_workers+0x2c0/0x2c0 [ 740.962001] [] kthread+0xc6/0xd0 [ 740.962001] [] ? kthread_freezable_should_stop+0x70/0x70 [ 740.962001] [] ret_from_fork+0x7c/0xb0 [ 740.962001] [] ? kthread_freezable_should_stop+0x70/0x70 [ 740.962001] Code: 89 e5 41 57 41 56 41 55 45 31 ed 41 54 53 48 89 fb 48 83 ec 18 48 8b 06 4c 8b 67 48 48 89 c1 30 c9 a8 04 4c 0f 45 e9 80 7f 58 00 <49> 8b 45 08 44 8b b0 00 01 00 00 78 0c 41 f6 44 24 10 04 0f 84 [ 740.962001] RIP [] process_one_work+0x30/0x500 [ 740.962001] RSP [ 740.962001] CR2: 0000000000000008 [ 740.962001] ---[ end trace 39181460000748de ]--- [ 740.962001] Kernel panic - not syncing: Fatal exception This can happen if there are some stripes left, fewer than MAX_STRIPE_BATCH. A worker is queued to handle them. But before calling raid5_do_work, raid5d handles those stripes making conf->active_stripe = 0. So mddev_suspend() can return. We might then free old worker resources before the queued raid5_do_work() handled them. When it runs, it crashes. raid5d() raid5_store_group_thread_cnt() queue_work mddev_suspend() handle_strips active_stripe=0 free(old worker resources) process_one_work raid5_do_work To avoid this, we should only flush the worker resources before freeing them. This fixes a bug introduced in 3.12 so is suitable for the 3.12.x stable series. Cc: stable@vger.kernel.org (3.12) Fixes: b721420e8719131896b009b11edbbd27 Signed-off-by: Jianpeng Ma Signed-off-by: NeilBrown Reviewed-by: Shaohua Li diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c index 6c724fd..fea6772 100644 --- a/drivers/md/raid5.c +++ b/drivers/md/raid5.c @@ -5413,6 +5413,9 @@ raid5_store_group_thread_cnt(struct mddev *mddev, const char *page, size_t len) old_groups = conf->worker_groups; old_group_cnt = conf->worker_cnt_per_group; + if (old_groups) + flush_workqueue(raid5_wq); + conf->worker_groups = NULL; err = alloc_thread_groups(conf, new); if (err) { -- cgit v0.10.2 From 60aaf933854511630e16be4efe0f96485e132de4 Mon Sep 17 00:00:00 2001 From: majianpeng Date: Thu, 14 Nov 2013 15:16:20 +1100 Subject: md/raid5: Use conf->device_lock protect changing of multi-thread resources. When we change group_thread_cnt from sysfs entry, it can OOPS. The kernel messages are: [ 135.299021] BUG: unable to handle kernel NULL pointer dereference at (null) [ 135.299073] IP: [] handle_active_stripes+0x32b/0x440 [ 135.299107] PGD 0 [ 135.299122] Oops: 0000 [#1] SMP [ 135.299144] Modules linked in: netconsole e1000e ptp pps_core [ 135.299188] CPU: 3 PID: 2225 Comm: md0_raid5 Not tainted 3.12.0+ #24 [ 135.299214] Hardware name: To Be Filled By O.E.M. To Be Filled By O.E.M./To be filled by O.E.M., BIOS 080015 11/09/2011 [ 135.299255] task: ffff8800b9638f80 ti: ffff8800b77a4000 task.ti: ffff8800b77a4000 [ 135.299283] RIP: 0010:[] [] handle_active_stripes+0x32b/0x440 [ 135.299323] RSP: 0018:ffff8800b77a5c48 EFLAGS: 00010002 [ 135.299344] RAX: ffff880037bb5c70 RBX: 0000000000000000 RCX: 0000000000000008 [ 135.299371] RDX: ffff880037bb5cb8 RSI: 0000000000000001 RDI: ffff880037bb5c00 [ 135.299398] RBP: ffff8800b77a5d08 R08: 0000000000000001 R09: 0000000000000000 [ 135.299425] R10: ffff8800b77a5c98 R11: 00000000ffffffff R12: ffff880037bb5c00 [ 135.299452] R13: 0000000000000000 R14: 0000000000000000 R15: ffff880037bb5c70 [ 135.299479] FS: 0000000000000000(0000) GS:ffff88013fd80000(0000) knlGS:0000000000000000 [ 135.299510] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b [ 135.299532] CR2: 0000000000000000 CR3: 0000000001c0b000 CR4: 00000000000407e0 [ 135.299559] Stack: [ 135.299570] ffff8800b77a5c88 ffffffff8107383e ffff8800b77a5c88 ffff880037a64300 [ 135.299611] 000000000000ec08 ffff880037bb5cb8 ffff8800b77a5c98 ffffffffffffffd8 [ 135.299654] 000000000000ec08 ffff880037bb5c60 ffff8800b77a5c98 ffff8800b77a5c98 [ 135.299696] Call Trace: [ 135.299711] [] ? __wake_up+0x4e/0x70 [ 135.299733] [] raid5d+0x4c8/0x680 [ 135.299756] [] ? schedule_timeout+0x15d/0x1f0 [ 135.299781] [] md_thread+0x11f/0x170 [ 135.299804] [] ? wake_up_bit+0x40/0x40 [ 135.299826] [] ? md_rdev_init+0x110/0x110 [ 135.299850] [] kthread+0xc6/0xd0 [ 135.299871] [] ? kthread_freezable_should_stop+0x70/0x70 [ 135.299899] [] ret_from_fork+0x7c/0xb0 [ 135.299923] [] ? kthread_freezable_should_stop+0x70/0x70 [ 135.299951] Code: ff ff ff 0f 84 d7 fe ff ff e9 5c fe ff ff 66 90 41 8b b4 24 d8 01 00 00 45 31 ed 85 f6 0f 8e 7b fd ff ff 49 8b 9c 24 d0 01 00 00 <48> 3b 1b 49 89 dd 0f 85 67 fd ff ff 48 8d 43 28 31 d2 eb 17 90 [ 135.300005] RIP [] handle_active_stripes+0x32b/0x440 [ 135.300005] RSP [ 135.300005] CR2: 0000000000000000 [ 135.300005] ---[ end trace 504854e5bb7562ed ]--- [ 135.300005] Kernel panic - not syncing: Fatal exception This is because raid5d() can be running when the multi-thread resources are changed via system. We see need to provide locking. mddev->device_lock is suitable, but we cannot simple call alloc_thread_groups under this lock as we cannot allocate memory while holding a spinlock. So change alloc_thread_groups() to allocate and return the data structures, then raid5_store_group_thread_cnt() can take the lock while updating the pointers to the data structures. This fixes a bug introduced in 3.12 and so is suitable for the 3.12.x stable series. Fixes: b721420e8719131896b009b11edbbd27 Cc: stable@vger.kernel.org (3.12) Signed-off-by: Jianpeng Ma Signed-off-by: NeilBrown Reviewed-by: Shaohua Li diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c index fea6772..c7db410 100644 --- a/drivers/md/raid5.c +++ b/drivers/md/raid5.c @@ -5387,15 +5387,18 @@ raid5_show_group_thread_cnt(struct mddev *mddev, char *page) return 0; } -static int alloc_thread_groups(struct r5conf *conf, int cnt); +static int alloc_thread_groups(struct r5conf *conf, int cnt, + int *group_cnt, + int *worker_cnt_per_group, + struct r5worker_group **worker_groups); static ssize_t raid5_store_group_thread_cnt(struct mddev *mddev, const char *page, size_t len) { struct r5conf *conf = mddev->private; unsigned long new; int err; - struct r5worker_group *old_groups; - int old_group_cnt; + struct r5worker_group *new_groups, *old_groups; + int group_cnt, worker_cnt_per_group; if (len >= PAGE_SIZE) return -EINVAL; @@ -5411,17 +5414,19 @@ raid5_store_group_thread_cnt(struct mddev *mddev, const char *page, size_t len) mddev_suspend(mddev); old_groups = conf->worker_groups; - old_group_cnt = conf->worker_cnt_per_group; - if (old_groups) flush_workqueue(raid5_wq); - conf->worker_groups = NULL; - err = alloc_thread_groups(conf, new); - if (err) { - conf->worker_groups = old_groups; - conf->worker_cnt_per_group = old_group_cnt; - } else { + err = alloc_thread_groups(conf, new, + &group_cnt, &worker_cnt_per_group, + &new_groups); + if (!err) { + spin_lock_irq(&conf->device_lock); + conf->group_cnt = group_cnt; + conf->worker_cnt_per_group = worker_cnt_per_group; + conf->worker_groups = new_groups; + spin_unlock_irq(&conf->device_lock); + if (old_groups) kfree(old_groups[0].workers); kfree(old_groups); @@ -5451,33 +5456,36 @@ static struct attribute_group raid5_attrs_group = { .attrs = raid5_attrs, }; -static int alloc_thread_groups(struct r5conf *conf, int cnt) +static int alloc_thread_groups(struct r5conf *conf, int cnt, + int *group_cnt, + int *worker_cnt_per_group, + struct r5worker_group **worker_groups) { int i, j, k; ssize_t size; struct r5worker *workers; - conf->worker_cnt_per_group = cnt; + *worker_cnt_per_group = cnt; if (cnt == 0) { - conf->worker_groups = NULL; + *group_cnt = 0; + *worker_groups = NULL; return 0; } - conf->group_cnt = num_possible_nodes(); + *group_cnt = num_possible_nodes(); size = sizeof(struct r5worker) * cnt; - workers = kzalloc(size * conf->group_cnt, GFP_NOIO); - conf->worker_groups = kzalloc(sizeof(struct r5worker_group) * - conf->group_cnt, GFP_NOIO); - if (!conf->worker_groups || !workers) { + workers = kzalloc(size * *group_cnt, GFP_NOIO); + *worker_groups = kzalloc(sizeof(struct r5worker_group) * + *group_cnt, GFP_NOIO); + if (!*worker_groups || !workers) { kfree(workers); - kfree(conf->worker_groups); - conf->worker_groups = NULL; + kfree(*worker_groups); return -ENOMEM; } - for (i = 0; i < conf->group_cnt; i++) { + for (i = 0; i < *group_cnt; i++) { struct r5worker_group *group; - group = &conf->worker_groups[i]; + group = worker_groups[i]; INIT_LIST_HEAD(&group->handle_list); group->conf = conf; group->workers = workers + i * cnt; @@ -5640,6 +5648,8 @@ static struct r5conf *setup_conf(struct mddev *mddev) struct disk_info *disk; char pers_name[6]; int i; + int group_cnt, worker_cnt_per_group; + struct r5worker_group *new_group; if (mddev->new_level != 5 && mddev->new_level != 4 @@ -5674,7 +5684,12 @@ static struct r5conf *setup_conf(struct mddev *mddev) if (conf == NULL) goto abort; /* Don't enable multi-threading by default*/ - if (alloc_thread_groups(conf, 0)) + if (!alloc_thread_groups(conf, 0, &group_cnt, &worker_cnt_per_group, + &new_group)) { + conf->group_cnt = group_cnt; + conf->worker_cnt_per_group = worker_cnt_per_group; + conf->worker_groups = new_group; + } else goto abort; spin_lock_init(&conf->device_lock); seqcount_init(&conf->gen_lock); -- cgit v0.10.2