From 1f965b19437017cea6d3f3f46acdc5acae5fd011 Mon Sep 17 00:00:00 2001 From: Heinz Mauelshagen Date: Tue, 21 Oct 2008 17:45:06 +0100 Subject: [PATCH] dm raid1: separate region_hash interface part1 Separate the region hash code from raid1 so it can be shared by forthcoming targets. Use BUG_ON() for failed async dm_io() calls. Signed-off-by: Heinz Mauelshagen Signed-off-by: Alasdair G Kergon --- drivers/md/Makefile | 2 +- drivers/md/dm-raid1.c | 789 +++++---------------------------- drivers/md/dm-region-hash.c | 704 +++++++++++++++++++++++++++++ include/linux/dm-region-hash.h | 104 +++++ 4 files changed, 912 insertions(+), 687 deletions(-) create mode 100644 drivers/md/dm-region-hash.c create mode 100644 include/linux/dm-region-hash.h diff --git a/drivers/md/Makefile b/drivers/md/Makefile index f1ef33dfd8cf..1c615804ea76 100644 --- a/drivers/md/Makefile +++ b/drivers/md/Makefile @@ -34,7 +34,7 @@ obj-$(CONFIG_DM_CRYPT) += dm-crypt.o obj-$(CONFIG_DM_DELAY) += dm-delay.o obj-$(CONFIG_DM_MULTIPATH) += dm-multipath.o dm-round-robin.o obj-$(CONFIG_DM_SNAPSHOT) += dm-snapshot.o -obj-$(CONFIG_DM_MIRROR) += dm-mirror.o dm-log.o +obj-$(CONFIG_DM_MIRROR) += dm-mirror.o dm-log.o dm-region-hash.o obj-$(CONFIG_DM_ZERO) += dm-zero.o quiet_cmd_unroll = UNROLL $@ diff --git a/drivers/md/dm-raid1.c b/drivers/md/dm-raid1.c index f358853af5cf..92dcc06832a4 100644 --- a/drivers/md/dm-raid1.c +++ b/drivers/md/dm-raid1.c @@ -1,118 +1,36 @@ /* * Copyright (C) 2003 Sistina Software Limited. + * Copyright (C) 2005-2008 Red Hat, Inc. All rights reserved. * * This file is released under the GPL. */ -#include - #include "dm-bio-list.h" #include "dm-bio-record.h" -#include #include #include #include #include #include -#include -#include #include -#include -#include +#include #include #include #include +#include #define DM_MSG_PREFIX "raid1" + +#define MAX_RECOVERY 1 /* Maximum number of regions recovered in parallel. */ #define DM_IO_PAGES 64 +#define DM_KCOPYD_PAGES 64 #define DM_RAID1_HANDLE_ERRORS 0x01 #define errors_handled(p) ((p)->features & DM_RAID1_HANDLE_ERRORS) static DECLARE_WAIT_QUEUE_HEAD(_kmirrord_recovery_stopped); -/*----------------------------------------------------------------- - * Region hash - * - * The mirror splits itself up into discrete regions. Each - * region can be in one of three states: clean, dirty, - * nosync. There is no need to put clean regions in the hash. - * - * In addition to being present in the hash table a region _may_ - * be present on one of three lists. - * - * clean_regions: Regions on this list have no io pending to - * them, they are in sync, we are no longer interested in them, - * they are dull. rh_update_states() will remove them from the - * hash table. - * - * quiesced_regions: These regions have been spun down, ready - * for recovery. rh_recovery_start() will remove regions from - * this list and hand them to kmirrord, which will schedule the - * recovery io with kcopyd. - * - * recovered_regions: Regions that kcopyd has successfully - * recovered. rh_update_states() will now schedule any delayed - * io, up the recovery_count, and remove the region from the - * hash. - * - * There are 2 locks: - * A rw spin lock 'hash_lock' protects just the hash table, - * this is never held in write mode from interrupt context, - * which I believe means that we only have to disable irqs when - * doing a write lock. - * - * An ordinary spin lock 'region_lock' that protects the three - * lists in the region_hash, with the 'state', 'list' and - * 'bhs_delayed' fields of the regions. This is used from irq - * context, so all other uses will have to suspend local irqs. - *---------------------------------------------------------------*/ -struct mirror_set; -struct region_hash { - struct mirror_set *ms; - uint32_t region_size; - unsigned region_shift; - - /* holds persistent region state */ - struct dm_dirty_log *log; - - /* hash table */ - rwlock_t hash_lock; - mempool_t *region_pool; - unsigned int mask; - unsigned int nr_buckets; - struct list_head *buckets; - - spinlock_t region_lock; - atomic_t recovery_in_flight; - struct semaphore recovery_count; - struct list_head clean_regions; - struct list_head quiesced_regions; - struct list_head recovered_regions; - struct list_head failed_recovered_regions; -}; - -enum { - RH_CLEAN, - RH_DIRTY, - RH_NOSYNC, - RH_RECOVERING -}; - -struct region { - struct region_hash *rh; /* FIXME: can we get rid of this ? */ - region_t key; - int state; - - struct list_head hash_list; - struct list_head list; - - atomic_t pending; - struct bio_list delayed_bios; -}; - - /*----------------------------------------------------------------- * Mirror set structures. *---------------------------------------------------------------*/ @@ -133,8 +51,7 @@ struct mirror { struct mirror_set { struct dm_target *ti; struct list_head list; - struct region_hash rh; - struct dm_kcopyd_client *kcopyd_client; + uint64_t features; spinlock_t lock; /* protects the lists */ @@ -142,6 +59,8 @@ struct mirror_set { struct bio_list writes; struct bio_list failures; + struct dm_region_hash *rh; + struct dm_kcopyd_client *kcopyd_client; struct dm_io_client *io_client; mempool_t *read_record_pool; @@ -160,25 +79,14 @@ struct mirror_set { struct work_struct trigger_event; - unsigned int nr_mirrors; + unsigned nr_mirrors; struct mirror mirror[0]; }; -/* - * Conversion fns - */ -static inline region_t bio_to_region(struct region_hash *rh, struct bio *bio) +static void wakeup_mirrord(void *context) { - return (bio->bi_sector - rh->ms->ti->begin) >> rh->region_shift; -} + struct mirror_set *ms = context; -static inline sector_t region_to_sector(struct region_hash *rh, region_t region) -{ - return region << rh->region_shift; -} - -static void wake(struct mirror_set *ms) -{ queue_work(ms->kmirrord_wq, &ms->kmirrord_work); } @@ -187,7 +95,7 @@ static void delayed_wake_fn(unsigned long data) struct mirror_set *ms = (struct mirror_set *) data; clear_bit(0, &ms->timer_pending); - wake(ms); + wakeup_mirrord(ms); } static void delayed_wake(struct mirror_set *ms) @@ -201,473 +109,34 @@ static void delayed_wake(struct mirror_set *ms) add_timer(&ms->timer); } -/* FIXME move this */ -static void queue_bio(struct mirror_set *ms, struct bio *bio, int rw); - -#define MIN_REGIONS 64 -#define MAX_RECOVERY 1 -static int rh_init(struct region_hash *rh, struct mirror_set *ms, - struct dm_dirty_log *log, uint32_t region_size, - region_t nr_regions) -{ - unsigned int nr_buckets, max_buckets; - size_t i; - - /* - * Calculate a suitable number of buckets for our hash - * table. - */ - max_buckets = nr_regions >> 6; - for (nr_buckets = 128u; nr_buckets < max_buckets; nr_buckets <<= 1) - ; - nr_buckets >>= 1; - - rh->ms = ms; - rh->log = log; - rh->region_size = region_size; - rh->region_shift = ffs(region_size) - 1; - rwlock_init(&rh->hash_lock); - rh->mask = nr_buckets - 1; - rh->nr_buckets = nr_buckets; - - rh->buckets = vmalloc(nr_buckets * sizeof(*rh->buckets)); - if (!rh->buckets) { - DMERR("unable to allocate region hash memory"); - return -ENOMEM; - } - - for (i = 0; i < nr_buckets; i++) - INIT_LIST_HEAD(rh->buckets + i); - - spin_lock_init(&rh->region_lock); - sema_init(&rh->recovery_count, 0); - atomic_set(&rh->recovery_in_flight, 0); - INIT_LIST_HEAD(&rh->clean_regions); - INIT_LIST_HEAD(&rh->quiesced_regions); - INIT_LIST_HEAD(&rh->recovered_regions); - INIT_LIST_HEAD(&rh->failed_recovered_regions); - - rh->region_pool = mempool_create_kmalloc_pool(MIN_REGIONS, - sizeof(struct region)); - if (!rh->region_pool) { - vfree(rh->buckets); - rh->buckets = NULL; - return -ENOMEM; - } - - return 0; -} - -static void rh_exit(struct region_hash *rh) -{ - unsigned int h; - struct region *reg, *nreg; - - BUG_ON(!list_empty(&rh->quiesced_regions)); - for (h = 0; h < rh->nr_buckets; h++) { - list_for_each_entry_safe(reg, nreg, rh->buckets + h, hash_list) { - BUG_ON(atomic_read(®->pending)); - mempool_free(reg, rh->region_pool); - } - } - - if (rh->log) - dm_dirty_log_destroy(rh->log); - if (rh->region_pool) - mempool_destroy(rh->region_pool); - vfree(rh->buckets); -} - -#define RH_HASH_MULT 2654435387U - -static inline unsigned int rh_hash(struct region_hash *rh, region_t region) -{ - return (unsigned int) ((region * RH_HASH_MULT) >> 12) & rh->mask; -} - -static struct region *__rh_lookup(struct region_hash *rh, region_t region) -{ - struct region *reg; - - list_for_each_entry (reg, rh->buckets + rh_hash(rh, region), hash_list) - if (reg->key == region) - return reg; - - return NULL; -} - -static void __rh_insert(struct region_hash *rh, struct region *reg) -{ - unsigned int h = rh_hash(rh, reg->key); - list_add(®->hash_list, rh->buckets + h); -} - -static struct region *__rh_alloc(struct region_hash *rh, region_t region) -{ - struct region *reg, *nreg; - - read_unlock(&rh->hash_lock); - nreg = mempool_alloc(rh->region_pool, GFP_ATOMIC); - if (unlikely(!nreg)) - nreg = kmalloc(sizeof(struct region), GFP_NOIO); - nreg->state = rh->log->type->in_sync(rh->log, region, 1) ? - RH_CLEAN : RH_NOSYNC; - nreg->rh = rh; - nreg->key = region; - - INIT_LIST_HEAD(&nreg->list); - - atomic_set(&nreg->pending, 0); - bio_list_init(&nreg->delayed_bios); - write_lock_irq(&rh->hash_lock); - - reg = __rh_lookup(rh, region); - if (reg) - /* we lost the race */ - mempool_free(nreg, rh->region_pool); - - else { - __rh_insert(rh, nreg); - if (nreg->state == RH_CLEAN) { - spin_lock(&rh->region_lock); - list_add(&nreg->list, &rh->clean_regions); - spin_unlock(&rh->region_lock); - } - reg = nreg; - } - write_unlock_irq(&rh->hash_lock); - read_lock(&rh->hash_lock); - - return reg; -} - -static inline struct region *__rh_find(struct region_hash *rh, region_t region) -{ - struct region *reg; - - reg = __rh_lookup(rh, region); - if (!reg) - reg = __rh_alloc(rh, region); - - return reg; -} - -static int rh_state(struct region_hash *rh, region_t region, int may_block) -{ - int r; - struct region *reg; - - read_lock(&rh->hash_lock); - reg = __rh_lookup(rh, region); - read_unlock(&rh->hash_lock); - - if (reg) - return reg->state; - - /* - * The region wasn't in the hash, so we fall back to the - * dirty log. - */ - r = rh->log->type->in_sync(rh->log, region, may_block); - - /* - * Any error from the dirty log (eg. -EWOULDBLOCK) gets - * taken as a RH_NOSYNC - */ - return r == 1 ? RH_CLEAN : RH_NOSYNC; -} - -static inline int rh_in_sync(struct region_hash *rh, - region_t region, int may_block) -{ - int state = rh_state(rh, region, may_block); - return state == RH_CLEAN || state == RH_DIRTY; -} - -static void dispatch_bios(struct mirror_set *ms, struct bio_list *bio_list) -{ - struct bio *bio; - - while ((bio = bio_list_pop(bio_list))) { - queue_bio(ms, bio, WRITE); - } -} - -static void complete_resync_work(struct region *reg, int success) -{ - struct region_hash *rh = reg->rh; - - rh->log->type->set_region_sync(rh->log, reg->key, success); - - /* - * Dispatch the bios before we call 'wake_up_all'. - * This is important because if we are suspending, - * we want to know that recovery is complete and - * the work queue is flushed. If we wake_up_all - * before we dispatch_bios (queue bios and call wake()), - * then we risk suspending before the work queue - * has been properly flushed. - */ - dispatch_bios(rh->ms, ®->delayed_bios); - if (atomic_dec_and_test(&rh->recovery_in_flight)) - wake_up_all(&_kmirrord_recovery_stopped); - up(&rh->recovery_count); -} - -static void rh_update_states(struct region_hash *rh) -{ - struct region *reg, *next; - - LIST_HEAD(clean); - LIST_HEAD(recovered); - LIST_HEAD(failed_recovered); - - /* - * Quickly grab the lists. - */ - write_lock_irq(&rh->hash_lock); - spin_lock(&rh->region_lock); - if (!list_empty(&rh->clean_regions)) { - list_splice_init(&rh->clean_regions, &clean); - - list_for_each_entry(reg, &clean, list) - list_del(®->hash_list); - } - - if (!list_empty(&rh->recovered_regions)) { - list_splice_init(&rh->recovered_regions, &recovered); - - list_for_each_entry (reg, &recovered, list) - list_del(®->hash_list); - } - - if (!list_empty(&rh->failed_recovered_regions)) { - list_splice_init(&rh->failed_recovered_regions, - &failed_recovered); - - list_for_each_entry(reg, &failed_recovered, list) - list_del(®->hash_list); - } - - spin_unlock(&rh->region_lock); - write_unlock_irq(&rh->hash_lock); - - /* - * All the regions on the recovered and clean lists have - * now been pulled out of the system, so no need to do - * any more locking. - */ - list_for_each_entry_safe (reg, next, &recovered, list) { - rh->log->type->clear_region(rh->log, reg->key); - complete_resync_work(reg, 1); - mempool_free(reg, rh->region_pool); - } - - list_for_each_entry_safe(reg, next, &failed_recovered, list) { - complete_resync_work(reg, errors_handled(rh->ms) ? 0 : 1); - mempool_free(reg, rh->region_pool); - } - - list_for_each_entry_safe(reg, next, &clean, list) { - rh->log->type->clear_region(rh->log, reg->key); - mempool_free(reg, rh->region_pool); - } - - rh->log->type->flush(rh->log); -} - -static void rh_inc(struct region_hash *rh, region_t region) -{ - struct region *reg; - - read_lock(&rh->hash_lock); - reg = __rh_find(rh, region); - - spin_lock_irq(&rh->region_lock); - atomic_inc(®->pending); - - if (reg->state == RH_CLEAN) { - reg->state = RH_DIRTY; - list_del_init(®->list); /* take off the clean list */ - spin_unlock_irq(&rh->region_lock); - - rh->log->type->mark_region(rh->log, reg->key); - } else - spin_unlock_irq(&rh->region_lock); - - - read_unlock(&rh->hash_lock); -} - -static void rh_inc_pending(struct region_hash *rh, struct bio_list *bios) +static void wakeup_all_recovery_waiters(void *context) { - struct bio *bio; - - for (bio = bios->head; bio; bio = bio->bi_next) - rh_inc(rh, bio_to_region(rh, bio)); + wake_up_all(&_kmirrord_recovery_stopped); } -static void rh_dec(struct region_hash *rh, region_t region) +static void queue_bio(struct mirror_set *ms, struct bio *bio, int rw) { unsigned long flags; - struct region *reg; int should_wake = 0; + struct bio_list *bl; - read_lock(&rh->hash_lock); - reg = __rh_lookup(rh, region); - read_unlock(&rh->hash_lock); - - spin_lock_irqsave(&rh->region_lock, flags); - if (atomic_dec_and_test(®->pending)) { - /* - * There is no pending I/O for this region. - * We can move the region to corresponding list for next action. - * At this point, the region is not yet connected to any list. - * - * If the state is RH_NOSYNC, the region should be kept off - * from clean list. - * The hash entry for RH_NOSYNC will remain in memory - * until the region is recovered or the map is reloaded. - */ - - /* do nothing for RH_NOSYNC */ - if (reg->state == RH_RECOVERING) { - list_add_tail(®->list, &rh->quiesced_regions); - } else if (reg->state == RH_DIRTY) { - reg->state = RH_CLEAN; - list_add(®->list, &rh->clean_regions); - } - should_wake = 1; - } - spin_unlock_irqrestore(&rh->region_lock, flags); + bl = (rw == WRITE) ? &ms->writes : &ms->reads; + spin_lock_irqsave(&ms->lock, flags); + should_wake = !(bl->head); + bio_list_add(bl, bio); + spin_unlock_irqrestore(&ms->lock, flags); if (should_wake) - wake(rh->ms); + wakeup_mirrord(ms); } -/* - * Starts quiescing a region in preparation for recovery. - */ -static int __rh_recovery_prepare(struct region_hash *rh) +static void dispatch_bios(void *context, struct bio_list *bio_list) { - int r; - struct region *reg; - region_t region; - - /* - * Ask the dirty log what's next. - */ - r = rh->log->type->get_resync_work(rh->log, ®ion); - if (r <= 0) - return r; - - /* - * Get this region, and start it quiescing by setting the - * recovering flag. - */ - read_lock(&rh->hash_lock); - reg = __rh_find(rh, region); - read_unlock(&rh->hash_lock); - - spin_lock_irq(&rh->region_lock); - reg->state = RH_RECOVERING; - - /* Already quiesced ? */ - if (atomic_read(®->pending)) - list_del_init(®->list); - else - list_move(®->list, &rh->quiesced_regions); - - spin_unlock_irq(&rh->region_lock); - - return 1; -} - -static void rh_recovery_prepare(struct region_hash *rh) -{ - /* Extra reference to avoid race with rh_stop_recovery */ - atomic_inc(&rh->recovery_in_flight); - - while (!down_trylock(&rh->recovery_count)) { - atomic_inc(&rh->recovery_in_flight); - if (__rh_recovery_prepare(rh) <= 0) { - atomic_dec(&rh->recovery_in_flight); - up(&rh->recovery_count); - break; - } - } - - /* Drop the extra reference */ - if (atomic_dec_and_test(&rh->recovery_in_flight)) - wake_up_all(&_kmirrord_recovery_stopped); -} - -/* - * Returns any quiesced regions. - */ -static struct region *rh_recovery_start(struct region_hash *rh) -{ - struct region *reg = NULL; - - spin_lock_irq(&rh->region_lock); - if (!list_empty(&rh->quiesced_regions)) { - reg = list_entry(rh->quiesced_regions.next, - struct region, list); - list_del_init(®->list); /* remove from the quiesced list */ - } - spin_unlock_irq(&rh->region_lock); - - return reg; -} - -static void rh_recovery_end(struct region *reg, int success) -{ - struct region_hash *rh = reg->rh; - - spin_lock_irq(&rh->region_lock); - if (success) - list_add(®->list, ®->rh->recovered_regions); - else { - reg->state = RH_NOSYNC; - list_add(®->list, ®->rh->failed_recovered_regions); - } - spin_unlock_irq(&rh->region_lock); - - wake(rh->ms); -} - -static int rh_flush(struct region_hash *rh) -{ - return rh->log->type->flush(rh->log); -} - -static void rh_delay(struct region_hash *rh, struct bio *bio) -{ - struct region *reg; - - read_lock(&rh->hash_lock); - reg = __rh_find(rh, bio_to_region(rh, bio)); - bio_list_add(®->delayed_bios, bio); - read_unlock(&rh->hash_lock); -} - -static void rh_stop_recovery(struct region_hash *rh) -{ - int i; - - /* wait for any recovering regions */ - for (i = 0; i < MAX_RECOVERY; i++) - down(&rh->recovery_count); -} - -static void rh_start_recovery(struct region_hash *rh) -{ - int i; - - for (i = 0; i < MAX_RECOVERY; i++) - up(&rh->recovery_count); + struct mirror_set *ms = context; + struct bio *bio; - wake(rh->ms); + while ((bio = bio_list_pop(bio_list))) + queue_bio(ms, bio, WRITE); } #define MIN_READ_RECORDS 20 @@ -777,8 +246,8 @@ out: static void recovery_complete(int read_err, unsigned long write_err, void *context) { - struct region *reg = (struct region *)context; - struct mirror_set *ms = reg->rh->ms; + struct dm_region *reg = context; + struct mirror_set *ms = dm_rh_region_context(reg); int m, bit = 0; if (read_err) { @@ -804,31 +273,33 @@ static void recovery_complete(int read_err, unsigned long write_err, } } - rh_recovery_end(reg, !(read_err || write_err)); + dm_rh_recovery_end(reg, !(read_err || write_err)); } -static int recover(struct mirror_set *ms, struct region *reg) +static int recover(struct mirror_set *ms, struct dm_region *reg) { int r; - unsigned int i; + unsigned i; struct dm_io_region from, to[DM_KCOPYD_MAX_REGIONS], *dest; struct mirror *m; unsigned long flags = 0; + region_t key = dm_rh_get_region_key(reg); + sector_t region_size = dm_rh_get_region_size(ms->rh); /* fill in the source */ m = get_default_mirror(ms); from.bdev = m->dev->bdev; - from.sector = m->offset + region_to_sector(reg->rh, reg->key); - if (reg->key == (ms->nr_regions - 1)) { + from.sector = m->offset + dm_rh_region_to_sector(ms->rh, key); + if (key == (ms->nr_regions - 1)) { /* * The final region may be smaller than * region_size. */ - from.count = ms->ti->len & (reg->rh->region_size - 1); + from.count = ms->ti->len & (region_size - 1); if (!from.count) - from.count = reg->rh->region_size; + from.count = region_size; } else - from.count = reg->rh->region_size; + from.count = region_size; /* fill in the destinations */ for (i = 0, dest = to; i < ms->nr_mirrors; i++) { @@ -837,7 +308,7 @@ static int recover(struct mirror_set *ms, struct region *reg) m = ms->mirror + i; dest->bdev = m->dev->bdev; - dest->sector = m->offset + region_to_sector(reg->rh, reg->key); + dest->sector = m->offset + dm_rh_region_to_sector(ms->rh, key); dest->count = from.count; dest++; } @@ -854,22 +325,22 @@ static int recover(struct mirror_set *ms, struct region *reg) static void do_recovery(struct mirror_set *ms) { + struct dm_region *reg; + struct dm_dirty_log *log = dm_rh_dirty_log(ms->rh); int r; - struct region *reg; - struct dm_dirty_log *log = ms->rh.log; /* * Start quiescing some regions. */ - rh_recovery_prepare(&ms->rh); + dm_rh_recovery_prepare(ms->rh); /* * Copy any already quiesced regions. */ - while ((reg = rh_recovery_start(&ms->rh))) { + while ((reg = dm_rh_recovery_start(ms->rh))) { r = recover(ms, reg); if (r) - rh_recovery_end(reg, 0); + dm_rh_recovery_end(reg, 0); } /* @@ -910,9 +381,10 @@ static int default_ok(struct mirror *m) static int mirror_available(struct mirror_set *ms, struct bio *bio) { - region_t region = bio_to_region(&ms->rh, bio); + struct dm_dirty_log *log = dm_rh_dirty_log(ms->rh); + region_t region = dm_rh_bio_to_region(ms->rh, bio); - if (ms->rh.log->type->in_sync(ms->rh.log, region, 0)) + if (log->type->in_sync(log, region, 0)) return choose_mirror(ms, bio->bi_sector) ? 1 : 0; return 0; @@ -986,7 +458,14 @@ static void read_async_bio(struct mirror *m, struct bio *bio) map_region(&io, m, bio); bio_set_m(bio, m); - (void) dm_io(&io_req, 1, &io, NULL); + BUG_ON(dm_io(&io_req, 1, &io, NULL)); +} + +static inline int region_in_sync(struct mirror_set *ms, region_t region, + int may_block) +{ + int state = dm_rh_get_state(ms->rh, region, may_block); + return state == DM_RH_CLEAN || state == DM_RH_DIRTY; } static void do_reads(struct mirror_set *ms, struct bio_list *reads) @@ -996,13 +475,13 @@ static void do_reads(struct mirror_set *ms, struct bio_list *reads) struct mirror *m; while ((bio = bio_list_pop(reads))) { - region = bio_to_region(&ms->rh, bio); + region = dm_rh_bio_to_region(ms->rh, bio); m = get_default_mirror(ms); /* * We can only read balance if the region is in sync. */ - if (likely(rh_in_sync(&ms->rh, region, 1))) + if (likely(region_in_sync(ms, region, 1))) m = choose_mirror(ms, bio->bi_sector); else if (m && atomic_read(&m->error_count)) m = NULL; @@ -1025,57 +504,6 @@ static void do_reads(struct mirror_set *ms, struct bio_list *reads) * NOSYNC: increment pending, just write to the default mirror *---------------------------------------------------------------*/ -/* __bio_mark_nosync - * @ms - * @bio - * @done - * @error - * - * The bio was written on some mirror(s) but failed on other mirror(s). - * We can successfully endio the bio but should avoid the region being - * marked clean by setting the state RH_NOSYNC. - * - * This function is _not_ safe in interrupt context! - */ -static void __bio_mark_nosync(struct mirror_set *ms, - struct bio *bio, unsigned done, int error) -{ - unsigned long flags; - struct region_hash *rh = &ms->rh; - struct dm_dirty_log *log = ms->rh.log; - struct region *reg; - region_t region = bio_to_region(rh, bio); - int recovering = 0; - - /* We must inform the log that the sync count has changed. */ - log->type->set_region_sync(log, region, 0); - ms->in_sync = 0; - - read_lock(&rh->hash_lock); - reg = __rh_find(rh, region); - read_unlock(&rh->hash_lock); - - /* region hash entry should exist because write was in-flight */ - BUG_ON(!reg); - BUG_ON(!list_empty(®->list)); - - spin_lock_irqsave(&rh->region_lock, flags); - /* - * Possible cases: - * 1) RH_DIRTY - * 2) RH_NOSYNC: was dirty, other preceeding writes failed - * 3) RH_RECOVERING: flushing pending writes - * Either case, the region should have not been connected to list. - */ - recovering = (reg->state == RH_RECOVERING); - reg->state = RH_NOSYNC; - BUG_ON(!list_empty(®->list)); - spin_unlock_irqrestore(&rh->region_lock, flags); - - bio_endio(bio, error); - if (recovering) - complete_resync_work(reg, 0); -} static void write_callback(unsigned long error, void *context) { @@ -1120,7 +548,7 @@ static void write_callback(unsigned long error, void *context) bio_list_add(&ms->failures, bio); spin_unlock_irqrestore(&ms->lock, flags); if (should_wake) - wake(ms); + wakeup_mirrord(ms); return; } out: @@ -1150,7 +578,7 @@ static void do_write(struct mirror_set *ms, struct bio *bio) */ bio_set_m(bio, get_default_mirror(ms)); - (void) dm_io(&io_req, ms->nr_mirrors, io, NULL); + BUG_ON(dm_io(&io_req, ms->nr_mirrors, io, NULL)); } static void do_writes(struct mirror_set *ms, struct bio_list *writes) @@ -1170,18 +598,19 @@ static void do_writes(struct mirror_set *ms, struct bio_list *writes) bio_list_init(&recover); while ((bio = bio_list_pop(writes))) { - state = rh_state(&ms->rh, bio_to_region(&ms->rh, bio), 1); + state = dm_rh_get_state(ms->rh, + dm_rh_bio_to_region(ms->rh, bio), 1); switch (state) { - case RH_CLEAN: - case RH_DIRTY: + case DM_RH_CLEAN: + case DM_RH_DIRTY: this_list = &sync; break; - case RH_NOSYNC: + case DM_RH_NOSYNC: this_list = &nosync; break; - case RH_RECOVERING: + case DM_RH_RECOVERING: this_list = &recover; break; } @@ -1194,9 +623,9 @@ static void do_writes(struct mirror_set *ms, struct bio_list *writes) * be written to (writes to recover regions are going to * be delayed). */ - rh_inc_pending(&ms->rh, &sync); - rh_inc_pending(&ms->rh, &nosync); - ms->log_failure = rh_flush(&ms->rh) ? 1 : 0; + dm_rh_inc_pending(ms->rh, &sync); + dm_rh_inc_pending(ms->rh, &nosync); + ms->log_failure = dm_rh_flush(ms->rh) ? 1 : 0; /* * Dispatch io. @@ -1205,13 +634,13 @@ static void do_writes(struct mirror_set *ms, struct bio_list *writes) spin_lock_irq(&ms->lock); bio_list_merge(&ms->failures, &sync); spin_unlock_irq(&ms->lock); - wake(ms); + wakeup_mirrord(ms); } else while ((bio = bio_list_pop(&sync))) do_write(ms, bio); while ((bio = bio_list_pop(&recover))) - rh_delay(&ms->rh, bio); + dm_rh_delay(ms->rh, bio); while ((bio = bio_list_pop(&nosync))) { map_bio(get_default_mirror(ms), bio); @@ -1228,7 +657,8 @@ static void do_failures(struct mirror_set *ms, struct bio_list *failures) if (!ms->log_failure) { while ((bio = bio_list_pop(failures))) - __bio_mark_nosync(ms, bio, bio->bi_size, 0); + ms->in_sync = 0; + dm_rh_mark_nosync(ms->rh, bio, bio->bi_size, 0); return; } @@ -1281,8 +711,8 @@ static void trigger_event(struct work_struct *work) *---------------------------------------------------------------*/ static void do_mirror(struct work_struct *work) { - struct mirror_set *ms =container_of(work, struct mirror_set, - kmirrord_work); + struct mirror_set *ms = container_of(work, struct mirror_set, + kmirrord_work); struct bio_list reads, writes, failures; unsigned long flags; @@ -1295,7 +725,7 @@ static void do_mirror(struct work_struct *work) bio_list_init(&ms->failures); spin_unlock_irqrestore(&ms->lock, flags); - rh_update_states(&ms->rh); + dm_rh_update_states(ms->rh, errors_handled(ms)); do_recovery(ms); do_reads(ms, &reads); do_writes(ms, &writes); @@ -1304,7 +734,6 @@ static void do_mirror(struct work_struct *work) dm_table_unplug_all(ms->ti->table); } - /*----------------------------------------------------------------- * Target functions *---------------------------------------------------------------*/ @@ -1351,7 +780,11 @@ static struct mirror_set *alloc_context(unsigned int nr_mirrors, return NULL; } - if (rh_init(&ms->rh, ms, dl, region_size, ms->nr_regions)) { + ms->rh = dm_region_hash_create(ms, dispatch_bios, wakeup_mirrord, + wakeup_all_recovery_waiters, + ms->ti->begin, MAX_RECOVERY, + dl, region_size, ms->nr_regions); + if (IS_ERR(ms->rh)) { ti->error = "Error creating dirty region hash"; dm_io_client_destroy(ms->io_client); mempool_destroy(ms->read_record_pool); @@ -1369,7 +802,7 @@ static void free_context(struct mirror_set *ms, struct dm_target *ti, dm_put_device(ti, ms->mirror[m].dev); dm_io_client_destroy(ms->io_client); - rh_exit(&ms->rh); + dm_region_hash_destroy(ms->rh); mempool_destroy(ms->read_record_pool); kfree(ms); } @@ -1409,10 +842,10 @@ static int get_mirror(struct mirror_set *ms, struct dm_target *ti, * Create dirty log: log_type #log_params */ static struct dm_dirty_log *create_dirty_log(struct dm_target *ti, - unsigned int argc, char **argv, - unsigned int *args_used) + unsigned argc, char **argv, + unsigned *args_used) { - unsigned int param_count; + unsigned param_count; struct dm_dirty_log *dl; if (argc < 2) { @@ -1543,7 +976,7 @@ static int mirror_ctr(struct dm_target *ti, unsigned int argc, char **argv) } ti->private = ms; - ti->split_io = ms->rh.region_size; + ti->split_io = dm_rh_get_region_size(ms->rh); ms->kmirrord_wq = create_singlethread_workqueue("kmirrord"); if (!ms->kmirrord_wq) { @@ -1578,11 +1011,11 @@ static int mirror_ctr(struct dm_target *ti, unsigned int argc, char **argv) goto err_destroy_wq; } - r = dm_kcopyd_client_create(DM_IO_PAGES, &ms->kcopyd_client); + r = dm_kcopyd_client_create(DM_KCOPYD_PAGES, &ms->kcopyd_client); if (r) goto err_destroy_wq; - wake(ms); + wakeup_mirrord(ms); return 0; err_destroy_wq: @@ -1603,22 +1036,6 @@ static void mirror_dtr(struct dm_target *ti) free_context(ms, ti, ms->nr_mirrors); } -static void queue_bio(struct mirror_set *ms, struct bio *bio, int rw) -{ - unsigned long flags; - int should_wake = 0; - struct bio_list *bl; - - bl = (rw == WRITE) ? &ms->writes : &ms->reads; - spin_lock_irqsave(&ms->lock, flags); - should_wake = !(bl->head); - bio_list_add(bl, bio); - spin_unlock_irqrestore(&ms->lock, flags); - - if (should_wake) - wake(ms); -} - /* * Mirror mapping function */ @@ -1629,16 +1046,16 @@ static int mirror_map(struct dm_target *ti, struct bio *bio, struct mirror *m; struct mirror_set *ms = ti->private; struct dm_raid1_read_record *read_record = NULL; + struct dm_dirty_log *log = dm_rh_dirty_log(ms->rh); if (rw == WRITE) { /* Save region for mirror_end_io() handler */ - map_context->ll = bio_to_region(&ms->rh, bio); + map_context->ll = dm_rh_bio_to_region(ms->rh, bio); queue_bio(ms, bio, rw); return DM_MAPIO_SUBMITTED; } - r = ms->rh.log->type->in_sync(ms->rh.log, - bio_to_region(&ms->rh, bio), 0); + r = log->type->in_sync(log, dm_rh_bio_to_region(ms->rh, bio), 0); if (r < 0 && r != -EWOULDBLOCK) return r; @@ -1686,7 +1103,7 @@ static int mirror_end_io(struct dm_target *ti, struct bio *bio, * We need to dec pending if this was a write. */ if (rw == WRITE) { - rh_dec(&ms->rh, map_context->ll); + dm_rh_dec(ms->rh, map_context->ll); return error; } @@ -1742,7 +1159,7 @@ out: static void mirror_presuspend(struct dm_target *ti) { struct mirror_set *ms = (struct mirror_set *) ti->private; - struct dm_dirty_log *log = ms->rh.log; + struct dm_dirty_log *log = dm_rh_dirty_log(ms->rh); atomic_set(&ms->suspend, 1); @@ -1750,10 +1167,10 @@ static void mirror_presuspend(struct dm_target *ti) * We must finish up all the work that we've * generated (i.e. recovery work). */ - rh_stop_recovery(&ms->rh); + dm_rh_stop_recovery(ms->rh); wait_event(_kmirrord_recovery_stopped, - !atomic_read(&ms->rh.recovery_in_flight)); + !dm_rh_recovery_in_flight(ms->rh)); if (log->type->presuspend && log->type->presuspend(log)) /* FIXME: need better error handling */ @@ -1771,7 +1188,7 @@ static void mirror_presuspend(struct dm_target *ti) static void mirror_postsuspend(struct dm_target *ti) { struct mirror_set *ms = ti->private; - struct dm_dirty_log *log = ms->rh.log; + struct dm_dirty_log *log = dm_rh_dirty_log(ms->rh); if (log->type->postsuspend && log->type->postsuspend(log)) /* FIXME: need better error handling */ @@ -1781,13 +1198,13 @@ static void mirror_postsuspend(struct dm_target *ti) static void mirror_resume(struct dm_target *ti) { struct mirror_set *ms = ti->private; - struct dm_dirty_log *log = ms->rh.log; + struct dm_dirty_log *log = dm_rh_dirty_log(ms->rh); atomic_set(&ms->suspend, 0); if (log->type->resume && log->type->resume(log)) /* FIXME: need better error handling */ DMWARN("log resume failed"); - rh_start_recovery(&ms->rh); + dm_rh_start_recovery(ms->rh); } /* @@ -1819,7 +1236,7 @@ static int mirror_status(struct dm_target *ti, status_type_t type, { unsigned int m, sz = 0; struct mirror_set *ms = (struct mirror_set *) ti->private; - struct dm_dirty_log *log = ms->rh.log; + struct dm_dirty_log *log = dm_rh_dirty_log(ms->rh); char buffer[ms->nr_mirrors + 1]; switch (type) { @@ -1832,15 +1249,15 @@ static int mirror_status(struct dm_target *ti, status_type_t type, buffer[m] = '\0'; DMEMIT("%llu/%llu 1 %s ", - (unsigned long long)log->type->get_sync_count(ms->rh.log), + (unsigned long long)log->type->get_sync_count(log), (unsigned long long)ms->nr_regions, buffer); - sz += log->type->status(ms->rh.log, type, result+sz, maxlen-sz); + sz += log->type->status(log, type, result+sz, maxlen-sz); break; case STATUSTYPE_TABLE: - sz = log->type->status(ms->rh.log, type, result, maxlen); + sz = log->type->status(log, type, result, maxlen); DMEMIT("%d", ms->nr_mirrors); for (m = 0; m < ms->nr_mirrors; m++) diff --git a/drivers/md/dm-region-hash.c b/drivers/md/dm-region-hash.c new file mode 100644 index 000000000000..59f8d9df9e1a --- /dev/null +++ b/drivers/md/dm-region-hash.c @@ -0,0 +1,704 @@ +/* + * Copyright (C) 2003 Sistina Software Limited. + * Copyright (C) 2004-2008 Red Hat, Inc. All rights reserved. + * + * This file is released under the GPL. + */ + +#include +#include + +#include +#include +#include +#include + +#include "dm.h" +#include "dm-bio-list.h" + +#define DM_MSG_PREFIX "region hash" + +/*----------------------------------------------------------------- + * Region hash + * + * The mirror splits itself up into discrete regions. Each + * region can be in one of three states: clean, dirty, + * nosync. There is no need to put clean regions in the hash. + * + * In addition to being present in the hash table a region _may_ + * be present on one of three lists. + * + * clean_regions: Regions on this list have no io pending to + * them, they are in sync, we are no longer interested in them, + * they are dull. dm_rh_update_states() will remove them from the + * hash table. + * + * quiesced_regions: These regions have been spun down, ready + * for recovery. rh_recovery_start() will remove regions from + * this list and hand them to kmirrord, which will schedule the + * recovery io with kcopyd. + * + * recovered_regions: Regions that kcopyd has successfully + * recovered. dm_rh_update_states() will now schedule any delayed + * io, up the recovery_count, and remove the region from the + * hash. + * + * There are 2 locks: + * A rw spin lock 'hash_lock' protects just the hash table, + * this is never held in write mode from interrupt context, + * which I believe means that we only have to disable irqs when + * doing a write lock. + * + * An ordinary spin lock 'region_lock' that protects the three + * lists in the region_hash, with the 'state', 'list' and + * 'delayed_bios' fields of the regions. This is used from irq + * context, so all other uses will have to suspend local irqs. + *---------------------------------------------------------------*/ +struct dm_region_hash { + uint32_t region_size; + unsigned region_shift; + + /* holds persistent region state */ + struct dm_dirty_log *log; + + /* hash table */ + rwlock_t hash_lock; + mempool_t *region_pool; + unsigned mask; + unsigned nr_buckets; + unsigned prime; + unsigned shift; + struct list_head *buckets; + + unsigned max_recovery; /* Max # of regions to recover in parallel */ + + spinlock_t region_lock; + atomic_t recovery_in_flight; + struct semaphore recovery_count; + struct list_head clean_regions; + struct list_head quiesced_regions; + struct list_head recovered_regions; + struct list_head failed_recovered_regions; + + void *context; + sector_t target_begin; + + /* Callback function to schedule bios writes */ + void (*dispatch_bios)(void *context, struct bio_list *bios); + + /* Callback function to wakeup callers worker thread. */ + void (*wakeup_workers)(void *context); + + /* Callback function to wakeup callers recovery waiters. */ + void (*wakeup_all_recovery_waiters)(void *context); +}; + +struct dm_region { + struct dm_region_hash *rh; /* FIXME: can we get rid of this ? */ + region_t key; + int state; + + struct list_head hash_list; + struct list_head list; + + atomic_t pending; + struct bio_list delayed_bios; +}; + +/* + * Conversion fns + */ +static region_t dm_rh_sector_to_region(struct dm_region_hash *rh, sector_t sector) +{ + return sector >> rh->region_shift; +} + +sector_t dm_rh_region_to_sector(struct dm_region_hash *rh, region_t region) +{ + return region << rh->region_shift; +} +EXPORT_SYMBOL_GPL(dm_rh_region_to_sector); + +region_t dm_rh_bio_to_region(struct dm_region_hash *rh, struct bio *bio) +{ + return dm_rh_sector_to_region(rh, bio->bi_sector - rh->target_begin); +} +EXPORT_SYMBOL_GPL(dm_rh_bio_to_region); + +void *dm_rh_region_context(struct dm_region *reg) +{ + return reg->rh->context; +} +EXPORT_SYMBOL_GPL(dm_rh_region_context); + +region_t dm_rh_get_region_key(struct dm_region *reg) +{ + return reg->key; +} +EXPORT_SYMBOL_GPL(dm_rh_get_region_key); + +sector_t dm_rh_get_region_size(struct dm_region_hash *rh) +{ + return rh->region_size; +} +EXPORT_SYMBOL_GPL(dm_rh_get_region_size); + +/* + * FIXME: shall we pass in a structure instead of all these args to + * dm_region_hash_create()???? + */ +#define RH_HASH_MULT 2654435387U +#define RH_HASH_SHIFT 12 + +#define MIN_REGIONS 64 +struct dm_region_hash *dm_region_hash_create( + void *context, void (*dispatch_bios)(void *context, + struct bio_list *bios), + void (*wakeup_workers)(void *context), + void (*wakeup_all_recovery_waiters)(void *context), + sector_t target_begin, unsigned max_recovery, + struct dm_dirty_log *log, uint32_t region_size, + region_t nr_regions) +{ + struct dm_region_hash *rh; + unsigned nr_buckets, max_buckets; + size_t i; + + /* + * Calculate a suitable number of buckets for our hash + * table. + */ + max_buckets = nr_regions >> 6; + for (nr_buckets = 128u; nr_buckets < max_buckets; nr_buckets <<= 1) + ; + nr_buckets >>= 1; + + rh = kmalloc(sizeof(*rh), GFP_KERNEL); + if (!rh) { + DMERR("unable to allocate region hash memory"); + return ERR_PTR(-ENOMEM); + } + + rh->context = context; + rh->dispatch_bios = dispatch_bios; + rh->wakeup_workers = wakeup_workers; + rh->wakeup_all_recovery_waiters = wakeup_all_recovery_waiters; + rh->target_begin = target_begin; + rh->max_recovery = max_recovery; + rh->log = log; + rh->region_size = region_size; + rh->region_shift = ffs(region_size) - 1; + rwlock_init(&rh->hash_lock); + rh->mask = nr_buckets - 1; + rh->nr_buckets = nr_buckets; + + rh->shift = RH_HASH_SHIFT; + rh->prime = RH_HASH_MULT; + + rh->buckets = vmalloc(nr_buckets * sizeof(*rh->buckets)); + if (!rh->buckets) { + DMERR("unable to allocate region hash bucket memory"); + kfree(rh); + return ERR_PTR(-ENOMEM); + } + + for (i = 0; i < nr_buckets; i++) + INIT_LIST_HEAD(rh->buckets + i); + + spin_lock_init(&rh->region_lock); + sema_init(&rh->recovery_count, 0); + atomic_set(&rh->recovery_in_flight, 0); + INIT_LIST_HEAD(&rh->clean_regions); + INIT_LIST_HEAD(&rh->quiesced_regions); + INIT_LIST_HEAD(&rh->recovered_regions); + INIT_LIST_HEAD(&rh->failed_recovered_regions); + + rh->region_pool = mempool_create_kmalloc_pool(MIN_REGIONS, + sizeof(struct dm_region)); + if (!rh->region_pool) { + vfree(rh->buckets); + kfree(rh); + rh = ERR_PTR(-ENOMEM); + } + + return rh; +} +EXPORT_SYMBOL_GPL(dm_region_hash_create); + +void dm_region_hash_destroy(struct dm_region_hash *rh) +{ + unsigned h; + struct dm_region *reg, *nreg; + + BUG_ON(!list_empty(&rh->quiesced_regions)); + for (h = 0; h < rh->nr_buckets; h++) { + list_for_each_entry_safe(reg, nreg, rh->buckets + h, + hash_list) { + BUG_ON(atomic_read(®->pending)); + mempool_free(reg, rh->region_pool); + } + } + + if (rh->log) + dm_dirty_log_destroy(rh->log); + + if (rh->region_pool) + mempool_destroy(rh->region_pool); + + vfree(rh->buckets); + kfree(rh); +} +EXPORT_SYMBOL_GPL(dm_region_hash_destroy); + +struct dm_dirty_log *dm_rh_dirty_log(struct dm_region_hash *rh) +{ + return rh->log; +} +EXPORT_SYMBOL_GPL(dm_rh_dirty_log); + +static unsigned rh_hash(struct dm_region_hash *rh, region_t region) +{ + return (unsigned) ((region * rh->prime) >> rh->shift) & rh->mask; +} + +static struct dm_region *__rh_lookup(struct dm_region_hash *rh, region_t region) +{ + struct dm_region *reg; + struct list_head *bucket = rh->buckets + rh_hash(rh, region); + + list_for_each_entry(reg, bucket, hash_list) + if (reg->key == region) + return reg; + + return NULL; +} + +static void __rh_insert(struct dm_region_hash *rh, struct dm_region *reg) +{ + list_add(®->hash_list, rh->buckets + rh_hash(rh, reg->key)); +} + +static struct dm_region *__rh_alloc(struct dm_region_hash *rh, region_t region) +{ + struct dm_region *reg, *nreg; + + nreg = mempool_alloc(rh->region_pool, GFP_ATOMIC); + if (unlikely(!nreg)) + nreg = kmalloc(sizeof(*nreg), GFP_NOIO); + + nreg->state = rh->log->type->in_sync(rh->log, region, 1) ? + DM_RH_CLEAN : DM_RH_NOSYNC; + nreg->rh = rh; + nreg->key = region; + INIT_LIST_HEAD(&nreg->list); + atomic_set(&nreg->pending, 0); + bio_list_init(&nreg->delayed_bios); + + write_lock_irq(&rh->hash_lock); + reg = __rh_lookup(rh, region); + if (reg) + /* We lost the race. */ + mempool_free(nreg, rh->region_pool); + else { + __rh_insert(rh, nreg); + if (nreg->state == DM_RH_CLEAN) { + spin_lock(&rh->region_lock); + list_add(&nreg->list, &rh->clean_regions); + spin_unlock(&rh->region_lock); + } + + reg = nreg; + } + write_unlock_irq(&rh->hash_lock); + + return reg; +} + +static struct dm_region *__rh_find(struct dm_region_hash *rh, region_t region) +{ + struct dm_region *reg; + + reg = __rh_lookup(rh, region); + if (!reg) { + read_unlock(&rh->hash_lock); + reg = __rh_alloc(rh, region); + read_lock(&rh->hash_lock); + } + + return reg; +} + +int dm_rh_get_state(struct dm_region_hash *rh, region_t region, int may_block) +{ + int r; + struct dm_region *reg; + + read_lock(&rh->hash_lock); + reg = __rh_lookup(rh, region); + read_unlock(&rh->hash_lock); + + if (reg) + return reg->state; + + /* + * The region wasn't in the hash, so we fall back to the + * dirty log. + */ + r = rh->log->type->in_sync(rh->log, region, may_block); + + /* + * Any error from the dirty log (eg. -EWOULDBLOCK) gets + * taken as a DM_RH_NOSYNC + */ + return r == 1 ? DM_RH_CLEAN : DM_RH_NOSYNC; +} +EXPORT_SYMBOL_GPL(dm_rh_get_state); + +static void complete_resync_work(struct dm_region *reg, int success) +{ + struct dm_region_hash *rh = reg->rh; + + rh->log->type->set_region_sync(rh->log, reg->key, success); + + /* + * Dispatch the bios before we call 'wake_up_all'. + * This is important because if we are suspending, + * we want to know that recovery is complete and + * the work queue is flushed. If we wake_up_all + * before we dispatch_bios (queue bios and call wake()), + * then we risk suspending before the work queue + * has been properly flushed. + */ + rh->dispatch_bios(rh->context, ®->delayed_bios); + if (atomic_dec_and_test(&rh->recovery_in_flight)) + rh->wakeup_all_recovery_waiters(rh->context); + up(&rh->recovery_count); +} + +/* dm_rh_mark_nosync + * @ms + * @bio + * @done + * @error + * + * The bio was written on some mirror(s) but failed on other mirror(s). + * We can successfully endio the bio but should avoid the region being + * marked clean by setting the state DM_RH_NOSYNC. + * + * This function is _not_ safe in interrupt context! + */ +void dm_rh_mark_nosync(struct dm_region_hash *rh, + struct bio *bio, unsigned done, int error) +{ + unsigned long flags; + struct dm_dirty_log *log = rh->log; + struct dm_region *reg; + region_t region = dm_rh_bio_to_region(rh, bio); + int recovering = 0; + + /* We must inform the log that the sync count has changed. */ + log->type->set_region_sync(log, region, 0); + + read_lock(&rh->hash_lock); + reg = __rh_find(rh, region); + read_unlock(&rh->hash_lock); + + /* region hash entry should exist because write was in-flight */ + BUG_ON(!reg); + BUG_ON(!list_empty(®->list)); + + spin_lock_irqsave(&rh->region_lock, flags); + /* + * Possible cases: + * 1) DM_RH_DIRTY + * 2) DM_RH_NOSYNC: was dirty, other preceeding writes failed + * 3) DM_RH_RECOVERING: flushing pending writes + * Either case, the region should have not been connected to list. + */ + recovering = (reg->state == DM_RH_RECOVERING); + reg->state = DM_RH_NOSYNC; + BUG_ON(!list_empty(®->list)); + spin_unlock_irqrestore(&rh->region_lock, flags); + + bio_endio(bio, error); + if (recovering) + complete_resync_work(reg, 0); +} +EXPORT_SYMBOL_GPL(dm_rh_mark_nosync); + +void dm_rh_update_states(struct dm_region_hash *rh, int errors_handled) +{ + struct dm_region *reg, *next; + + LIST_HEAD(clean); + LIST_HEAD(recovered); + LIST_HEAD(failed_recovered); + + /* + * Quickly grab the lists. + */ + write_lock_irq(&rh->hash_lock); + spin_lock(&rh->region_lock); + if (!list_empty(&rh->clean_regions)) { + list_splice_init(&rh->clean_regions, &clean); + + list_for_each_entry(reg, &clean, list) + list_del(®->hash_list); + } + + if (!list_empty(&rh->recovered_regions)) { + list_splice_init(&rh->recovered_regions, &recovered); + + list_for_each_entry(reg, &recovered, list) + list_del(®->hash_list); + } + + if (!list_empty(&rh->failed_recovered_regions)) { + list_splice_init(&rh->failed_recovered_regions, + &failed_recovered); + + list_for_each_entry(reg, &failed_recovered, list) + list_del(®->hash_list); + } + + spin_unlock(&rh->region_lock); + write_unlock_irq(&rh->hash_lock); + + /* + * All the regions on the recovered and clean lists have + * now been pulled out of the system, so no need to do + * any more locking. + */ + list_for_each_entry_safe(reg, next, &recovered, list) { + rh->log->type->clear_region(rh->log, reg->key); + complete_resync_work(reg, 1); + mempool_free(reg, rh->region_pool); + } + + list_for_each_entry_safe(reg, next, &failed_recovered, list) { + complete_resync_work(reg, errors_handled ? 0 : 1); + mempool_free(reg, rh->region_pool); + } + + list_for_each_entry_safe(reg, next, &clean, list) { + rh->log->type->clear_region(rh->log, reg->key); + mempool_free(reg, rh->region_pool); + } + + rh->log->type->flush(rh->log); +} +EXPORT_SYMBOL_GPL(dm_rh_update_states); + +static void rh_inc(struct dm_region_hash *rh, region_t region) +{ + struct dm_region *reg; + + read_lock(&rh->hash_lock); + reg = __rh_find(rh, region); + + spin_lock_irq(&rh->region_lock); + atomic_inc(®->pending); + + if (reg->state == DM_RH_CLEAN) { + reg->state = DM_RH_DIRTY; + list_del_init(®->list); /* take off the clean list */ + spin_unlock_irq(&rh->region_lock); + + rh->log->type->mark_region(rh->log, reg->key); + } else + spin_unlock_irq(&rh->region_lock); + + + read_unlock(&rh->hash_lock); +} + +void dm_rh_inc_pending(struct dm_region_hash *rh, struct bio_list *bios) +{ + struct bio *bio; + + for (bio = bios->head; bio; bio = bio->bi_next) + rh_inc(rh, dm_rh_bio_to_region(rh, bio)); +} +EXPORT_SYMBOL_GPL(dm_rh_inc_pending); + +void dm_rh_dec(struct dm_region_hash *rh, region_t region) +{ + unsigned long flags; + struct dm_region *reg; + int should_wake = 0; + + read_lock(&rh->hash_lock); + reg = __rh_lookup(rh, region); + read_unlock(&rh->hash_lock); + + spin_lock_irqsave(&rh->region_lock, flags); + if (atomic_dec_and_test(®->pending)) { + /* + * There is no pending I/O for this region. + * We can move the region to corresponding list for next action. + * At this point, the region is not yet connected to any list. + * + * If the state is DM_RH_NOSYNC, the region should be kept off + * from clean list. + * The hash entry for DM_RH_NOSYNC will remain in memory + * until the region is recovered or the map is reloaded. + */ + + /* do nothing for DM_RH_NOSYNC */ + if (reg->state == DM_RH_RECOVERING) { + list_add_tail(®->list, &rh->quiesced_regions); + } else if (reg->state == DM_RH_DIRTY) { + reg->state = DM_RH_CLEAN; + list_add(®->list, &rh->clean_regions); + } + should_wake = 1; + } + spin_unlock_irqrestore(&rh->region_lock, flags); + + if (should_wake) + rh->wakeup_workers(rh->context); +} +EXPORT_SYMBOL_GPL(dm_rh_dec); + +/* + * Starts quiescing a region in preparation for recovery. + */ +static int __rh_recovery_prepare(struct dm_region_hash *rh) +{ + int r; + region_t region; + struct dm_region *reg; + + /* + * Ask the dirty log what's next. + */ + r = rh->log->type->get_resync_work(rh->log, ®ion); + if (r <= 0) + return r; + + /* + * Get this region, and start it quiescing by setting the + * recovering flag. + */ + read_lock(&rh->hash_lock); + reg = __rh_find(rh, region); + read_unlock(&rh->hash_lock); + + spin_lock_irq(&rh->region_lock); + reg->state = DM_RH_RECOVERING; + + /* Already quiesced ? */ + if (atomic_read(®->pending)) + list_del_init(®->list); + else + list_move(®->list, &rh->quiesced_regions); + + spin_unlock_irq(&rh->region_lock); + + return 1; +} + +void dm_rh_recovery_prepare(struct dm_region_hash *rh) +{ + /* Extra reference to avoid race with dm_rh_stop_recovery */ + atomic_inc(&rh->recovery_in_flight); + + while (!down_trylock(&rh->recovery_count)) { + atomic_inc(&rh->recovery_in_flight); + if (__rh_recovery_prepare(rh) <= 0) { + atomic_dec(&rh->recovery_in_flight); + up(&rh->recovery_count); + break; + } + } + + /* Drop the extra reference */ + if (atomic_dec_and_test(&rh->recovery_in_flight)) + rh->wakeup_all_recovery_waiters(rh->context); +} +EXPORT_SYMBOL_GPL(dm_rh_recovery_prepare); + +/* + * Returns any quiesced regions. + */ +struct dm_region *dm_rh_recovery_start(struct dm_region_hash *rh) +{ + struct dm_region *reg = NULL; + + spin_lock_irq(&rh->region_lock); + if (!list_empty(&rh->quiesced_regions)) { + reg = list_entry(rh->quiesced_regions.next, + struct dm_region, list); + list_del_init(®->list); /* remove from the quiesced list */ + } + spin_unlock_irq(&rh->region_lock); + + return reg; +} +EXPORT_SYMBOL_GPL(dm_rh_recovery_start); + +void dm_rh_recovery_end(struct dm_region *reg, int success) +{ + struct dm_region_hash *rh = reg->rh; + + spin_lock_irq(&rh->region_lock); + if (success) + list_add(®->list, ®->rh->recovered_regions); + else { + reg->state = DM_RH_NOSYNC; + list_add(®->list, ®->rh->failed_recovered_regions); + } + spin_unlock_irq(&rh->region_lock); + + rh->wakeup_workers(rh->context); +} +EXPORT_SYMBOL_GPL(dm_rh_recovery_end); + +/* Return recovery in flight count. */ +int dm_rh_recovery_in_flight(struct dm_region_hash *rh) +{ + return atomic_read(&rh->recovery_in_flight); +} +EXPORT_SYMBOL_GPL(dm_rh_recovery_in_flight); + +int dm_rh_flush(struct dm_region_hash *rh) +{ + return rh->log->type->flush(rh->log); +} +EXPORT_SYMBOL_GPL(dm_rh_flush); + +void dm_rh_delay(struct dm_region_hash *rh, struct bio *bio) +{ + struct dm_region *reg; + + read_lock(&rh->hash_lock); + reg = __rh_find(rh, dm_rh_bio_to_region(rh, bio)); + bio_list_add(®->delayed_bios, bio); + read_unlock(&rh->hash_lock); +} +EXPORT_SYMBOL_GPL(dm_rh_delay); + +void dm_rh_stop_recovery(struct dm_region_hash *rh) +{ + int i; + + /* wait for any recovering regions */ + for (i = 0; i < rh->max_recovery; i++) + down(&rh->recovery_count); +} +EXPORT_SYMBOL_GPL(dm_rh_stop_recovery); + +void dm_rh_start_recovery(struct dm_region_hash *rh) +{ + int i; + + for (i = 0; i < rh->max_recovery; i++) + up(&rh->recovery_count); + + rh->wakeup_workers(rh->context); +} +EXPORT_SYMBOL_GPL(dm_rh_start_recovery); + +MODULE_DESCRIPTION(DM_NAME " region hash"); +MODULE_AUTHOR("Joe Thornber/Heinz Mauelshagen "); +MODULE_LICENSE("GPL"); diff --git a/include/linux/dm-region-hash.h b/include/linux/dm-region-hash.h new file mode 100644 index 000000000000..a9e652a41373 --- /dev/null +++ b/include/linux/dm-region-hash.h @@ -0,0 +1,104 @@ +/* + * Copyright (C) 2003 Sistina Software Limited. + * Copyright (C) 2004-2008 Red Hat, Inc. All rights reserved. + * + * Device-Mapper dirty region hash interface. + * + * This file is released under the GPL. + */ + +#ifndef DM_REGION_HASH_H +#define DM_REGION_HASH_H + +#include + +/*----------------------------------------------------------------- + * Region hash + *----------------------------------------------------------------*/ +struct dm_region_hash; +struct dm_region; + +/* + * States a region can have. + */ +enum dm_rh_region_states { + DM_RH_CLEAN = 0x01, /* No writes in flight. */ + DM_RH_DIRTY = 0x02, /* Writes in flight. */ + DM_RH_NOSYNC = 0x04, /* Out of sync. */ + DM_RH_RECOVERING = 0x08, /* Under resynchronization. */ +}; + +/* + * Region hash create/destroy. + */ +struct bio_list; +struct dm_region_hash *dm_region_hash_create( + void *context, void (*dispatch_bios)(void *context, + struct bio_list *bios), + void (*wakeup_workers)(void *context), + void (*wakeup_all_recovery_waiters)(void *context), + sector_t target_begin, unsigned max_recovery, + struct dm_dirty_log *log, uint32_t region_size, + region_t nr_regions); +void dm_region_hash_destroy(struct dm_region_hash *rh); + +struct dm_dirty_log *dm_rh_dirty_log(struct dm_region_hash *rh); + +/* + * Conversion functions. + */ +region_t dm_rh_bio_to_region(struct dm_region_hash *rh, struct bio *bio); +sector_t dm_rh_region_to_sector(struct dm_region_hash *rh, region_t region); +void *dm_rh_region_context(struct dm_region *reg); + +/* + * Get region size and key (ie. number of the region). + */ +sector_t dm_rh_get_region_size(struct dm_region_hash *rh); +region_t dm_rh_get_region_key(struct dm_region *reg); + +/* + * Get/set/update region state (and dirty log). + * + */ +int dm_rh_get_state(struct dm_region_hash *rh, region_t region, int may_block); +void dm_rh_set_state(struct dm_region_hash *rh, region_t region, + enum dm_rh_region_states state, int may_block); + +/* Non-zero errors_handled leaves the state of the region NOSYNC */ +void dm_rh_update_states(struct dm_region_hash *rh, int errors_handled); + +/* Flush the region hash and dirty log. */ +int dm_rh_flush(struct dm_region_hash *rh); + +/* Inc/dec pending count on regions. */ +void dm_rh_inc_pending(struct dm_region_hash *rh, struct bio_list *bios); +void dm_rh_dec(struct dm_region_hash *rh, region_t region); + +/* Delay bios on regions. */ +void dm_rh_delay(struct dm_region_hash *rh, struct bio *bio); + +void dm_rh_mark_nosync(struct dm_region_hash *rh, + struct bio *bio, unsigned done, int error); + +/* + * Region recovery control. + */ + +/* Prepare some regions for recovery by starting to quiesce them. */ +void dm_rh_recovery_prepare(struct dm_region_hash *rh); + +/* Try fetching a quiesced region for recovery. */ +struct dm_region *dm_rh_recovery_start(struct dm_region_hash *rh); + +/* Report recovery end on a region. */ +void dm_rh_recovery_end(struct dm_region *reg, int error); + +/* Returns number of regions with recovery work outstanding. */ +int dm_rh_recovery_in_flight(struct dm_region_hash *rh); + +/* Start/stop recovery. */ +void dm_rh_start_recovery(struct dm_region_hash *rh); +void dm_rh_stop_recovery(struct dm_region_hash *rh); + +#endif /* DM_REGION_HASH_H */ -- 2.20.1