/* * Copyright (C) 2003 Sistina Software Limited. * * This file is released under the GPL. */ #include "dm.h" #include "dm-bio-list.h" #include "dm-io.h" #include "dm-log.h" #include "kcopyd.h" #include <linux/ctype.h> #include <linux/init.h> #include <linux/mempool.h> #include <linux/module.h> #include <linux/pagemap.h> #include <linux/slab.h> #include <linux/time.h> #include <linux/vmalloc.h> #include <linux/workqueue.h> #define DM_MSG_PREFIX "raid1" static struct workqueue_struct *_kmirrord_wq; static struct work_struct _kmirrord_work; static DECLARE_WAIT_QUEUE_HEAD(_kmirrord_recovery_stopped); static inline void wake(void) { queue_work(_kmirrord_wq, &_kmirrord_work); } /*----------------------------------------------------------------- * 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 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; }; 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. *---------------------------------------------------------------*/ struct mirror { atomic_t error_count; struct dm_dev *dev; sector_t offset; }; struct mirror_set { struct dm_target *ti; struct list_head list; struct region_hash rh; struct kcopyd_client *kcopyd_client; spinlock_t lock; /* protects the next two lists */ struct bio_list reads; struct bio_list writes; /* recovery */ region_t nr_regions; int in_sync; struct mirror *default_mirror; /* Default mirror */ unsigned int nr_mirrors; struct mirror mirror[0]; }; /* * Conversion fns */ static inline region_t bio_to_region(struct region_hash *rh, struct bio *bio) { return (bio->bi_sector - rh->ms->ti->begin) >> rh->region_shift; } static inline sector_t region_to_sector(struct region_hash *rh, region_t region) { return region << rh->region_shift; } /* 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 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); 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_destroy_dirty_log(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_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); /* * Quickly grab the lists. */ write_lock_irq(&rh->hash_lock); spin_lock(&rh->region_lock); if (!list_empty(&rh->clean_regions)) { list_splice(&rh->clean_regions, &clean); INIT_LIST_HEAD(&rh->clean_regions); list_for_each_entry (reg, &clean, list) { rh->log->type->clear_region(rh->log, reg->key); list_del(®->hash_list); } } if (!list_empty(&rh->recovered_regions)) { list_splice(&rh->recovered_regions, &recovered); INIT_LIST_HEAD(&rh->recovered_regions); list_for_each_entry (reg, &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); } if (!list_empty(&recovered)) rh->log->type->flush(rh->log); list_for_each_entry_safe (reg, next, &clean, list) mempool_free(reg, rh->region_pool); } 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) { struct bio *bio; for (bio = bios->head; bio; bio = bio->bi_next) rh_inc(rh, bio_to_region(rh, bio)); } static void rh_dec(struct region_hash *rh, region_t region) { unsigned long flags; struct 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 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); if (should_wake) wake(); } /* * Starts quiescing a region in preparation for recovery. */ static int __rh_recovery_prepare(struct region_hash *rh) { 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; } /* FIXME: success ignored for now */ static void rh_recovery_end(struct region *reg, int success) { struct region_hash *rh = reg->rh; spin_lock_irq(&rh->region_lock); list_add(®->list, ®->rh->recovered_regions); spin_unlock_irq(&rh->region_lock); wake(); } static void rh_flush(struct region_hash *rh) { 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); wake(); } /* * Every mirror should look like this one. */ #define DEFAULT_MIRROR 0 /* * This is yucky. We squirrel the mirror_set struct away inside * bi_next for write buffers. This is safe since the bh * doesn't get submitted to the lower levels of block layer. */ static struct mirror_set *bio_get_ms(struct bio *bio) { return (struct mirror_set *) bio->bi_next; } static void bio_set_ms(struct bio *bio, struct mirror_set *ms) { bio->bi_next = (struct bio *) ms; } /*----------------------------------------------------------------- * Recovery. * * When a mirror is first activated we may find that some regions * are in the no-sync state. We have to recover these by * recopying from the default mirror to all the others. *---------------------------------------------------------------*/ static void recovery_complete(int read_err, unsigned int write_err, void *context) { struct region *reg = (struct region *) context; /* FIXME: better error handling */ rh_recovery_end(reg, !(read_err || write_err)); } static int recover(struct mirror_set *ms, struct region *reg) { int r; unsigned int i; struct io_region from, to[KCOPYD_MAX_REGIONS], *dest; struct mirror *m; unsigned long flags = 0; /* fill in the source */ m = ms->default_mirror; from.bdev = m->dev->bdev; from.sector = m->offset + region_to_sector(reg->rh, reg->key); if (reg->key == (ms->nr_regions - 1)) { /* * The final region may be smaller than * region_size. */ from.count = ms->ti->len & (reg->rh->region_size - 1); if (!from.count) from.count = reg->rh->region_size; } else from.count = reg->rh->region_size; /* fill in the destinations */ for (i = 0, dest = to; i < ms->nr_mirrors; i++) { if (&ms->mirror[i] == ms->default_mirror) continue; m = ms->mirror + i; dest->bdev = m->dev->bdev; dest->sector = m->offset + region_to_sector(reg->rh, reg->key); dest->count = from.count; dest++; } /* hand to kcopyd */ set_bit(KCOPYD_IGNORE_ERROR, &flags); r = kcopyd_copy(ms->kcopyd_client, &from, ms->nr_mirrors - 1, to, flags, recovery_complete, reg); return r; } static void do_recovery(struct mirror_set *ms) { int r; struct region *reg; struct dirty_log *log = ms->rh.log; /* * Start quiescing some regions. */ rh_recovery_prepare(&ms->rh); /* * Copy any already quiesced regions. */ while ((reg = rh_recovery_start(&ms->rh))) { r = recover(ms, reg); if (r) rh_recovery_end(reg, 0); } /* * Update the in sync flag. */ if (!ms->in_sync && (log->type->get_sync_count(log) == ms->nr_regions)) { /* the sync is complete */ dm_table_event(ms->ti->table); ms->in_sync = 1; } } /*----------------------------------------------------------------- * Reads *---------------------------------------------------------------*/ static struct mirror *choose_mirror(struct mirror_set *ms, sector_t sector) { /* FIXME: add read balancing */ return ms->default_mirror; } /* * remap a buffer to a particular mirror. */ static void map_bio(struct mirror_set *ms, struct mirror *m, struct bio *bio) { bio->bi_bdev = m->dev->bdev; bio->bi_sector = m->offset + (bio->bi_sector - ms->ti->begin); } static void do_reads(struct mirror_set *ms, struct bio_list *reads) { region_t region; struct bio *bio; struct mirror *m; while ((bio = bio_list_pop(reads))) { region = bio_to_region(&ms->rh, bio); /* * We can only read balance if the region is in sync. */ if (rh_in_sync(&ms->rh, region, 0)) m = choose_mirror(ms, bio->bi_sector); else m = ms->default_mirror; map_bio(ms, m, bio); generic_make_request(bio); } } /*----------------------------------------------------------------- * Writes. * * We do different things with the write io depending on the * state of the region that it's in: * * SYNC: increment pending, use kcopyd to write to *all* mirrors * RECOVERING: delay the io until recovery completes * NOSYNC: increment pending, just write to the default mirror *---------------------------------------------------------------*/ static void write_callback(unsigned long error, void *context) { unsigned int i; int uptodate = 1; struct bio *bio = (struct bio *) context; struct mirror_set *ms; ms = bio_get_ms(bio); bio_set_ms(bio, NULL); /* * NOTE: We don't decrement the pending count here, * instead it is done by the targets endio function. * This way we handle both writes to SYNC and NOSYNC * regions with the same code. */ if (error) { /* * only error the io if all mirrors failed. * FIXME: bogus */ uptodate = 0; for (i = 0; i < ms->nr_mirrors; i++) if (!test_bit(i, &error)) { uptodate = 1; break; } } bio_endio(bio, bio->bi_size, 0); } static void do_write(struct mirror_set *ms, struct bio *bio) { unsigned int i; struct io_region io[KCOPYD_MAX_REGIONS+1]; struct mirror *m; for (i = 0; i < ms->nr_mirrors; i++) { m = ms->mirror + i; io[i].bdev = m->dev->bdev; io[i].sector = m->offset + (bio->bi_sector - ms->ti->begin); io[i].count = bio->bi_size >> 9; } bio_set_ms(bio, ms); dm_io_async_bvec(ms->nr_mirrors, io, WRITE, bio->bi_io_vec + bio->bi_idx, write_callback, bio); } static void do_writes(struct mirror_set *ms, struct bio_list *writes) { int state; struct bio *bio; struct bio_list sync, nosync, recover, *this_list = NULL; if (!writes->head) return; /* * Classify each write. */ bio_list_init(&sync); bio_list_init(&nosync); bio_list_init(&recover); while ((bio = bio_list_pop(writes))) { state = rh_state(&ms->rh, bio_to_region(&ms->rh, bio), 1); switch (state) { case RH_CLEAN: case RH_DIRTY: this_list = &sync; break; case RH_NOSYNC: this_list = &nosync; break; case RH_RECOVERING: this_list = &recover; break; } bio_list_add(this_list, bio); } /* * Increment the pending counts for any regions that will * be written to (writes to recover regions are going to * be delayed). */ rh_inc_pending(&ms->rh, &sync); rh_inc_pending(&ms->rh, &nosync); rh_flush(&ms->rh); /* * Dispatch io. */ while ((bio = bio_list_pop(&sync))) do_write(ms, bio); while ((bio = bio_list_pop(&recover))) rh_delay(&ms->rh, bio); while ((bio = bio_list_pop(&nosync))) { map_bio(ms, ms->default_mirror, bio); generic_make_request(bio); } } /*----------------------------------------------------------------- * kmirrord *---------------------------------------------------------------*/ static LIST_HEAD(_mirror_sets); static DECLARE_RWSEM(_mirror_sets_lock); static void do_mirror(struct mirror_set *ms) { struct bio_list reads, writes; spin_lock(&ms->lock); reads = ms->reads; writes = ms->writes; bio_list_init(&ms->reads); bio_list_init(&ms->writes); spin_unlock(&ms->lock); rh_update_states(&ms->rh); do_recovery(ms); do_reads(ms, &reads); do_writes(ms, &writes); } static void do_work(struct work_struct *ignored) { struct mirror_set *ms; down_read(&_mirror_sets_lock); list_for_each_entry (ms, &_mirror_sets, list) do_mirror(ms); up_read(&_mirror_sets_lock); } /*----------------------------------------------------------------- * Target functions *---------------------------------------------------------------*/ static struct mirror_set *alloc_context(unsigned int nr_mirrors, uint32_t region_size, struct dm_target *ti, struct dirty_log *dl) { size_t len; struct mirror_set *ms = NULL; if (array_too_big(sizeof(*ms), sizeof(ms->mirror[0]), nr_mirrors)) return NULL; len = sizeof(*ms) + (sizeof(ms->mirror[0]) * nr_mirrors); ms = kmalloc(len, GFP_KERNEL); if (!ms) { ti->error = "Cannot allocate mirror context"; return NULL; } memset(ms, 0, len); spin_lock_init(&ms->lock); ms->ti = ti; ms->nr_mirrors = nr_mirrors; ms->nr_regions = dm_sector_div_up(ti->len, region_size); ms->in_sync = 0; ms->default_mirror = &ms->mirror[DEFAULT_MIRROR]; if (rh_init(&ms->rh, ms, dl, region_size, ms->nr_regions)) { ti->error = "Error creating dirty region hash"; kfree(ms); return NULL; } return ms; } static void free_context(struct mirror_set *ms, struct dm_target *ti, unsigned int m) { while (m--) dm_put_device(ti, ms->mirror[m].dev); rh_exit(&ms->rh); kfree(ms); } static inline int _check_region_size(struct dm_target *ti, uint32_t size) { return !(size % (PAGE_SIZE >> 9) || (size & (size - 1)) || size > ti->len); } static int get_mirror(struct mirror_set *ms, struct dm_target *ti, unsigned int mirror, char **argv) { unsigned long long offset; if (sscanf(argv[1], "%llu", &offset) != 1) { ti->error = "Invalid offset"; return -EINVAL; } if (dm_get_device(ti, argv[0], offset, ti->len, dm_table_get_mode(ti->table), &ms->mirror[mirror].dev)) { ti->error = "Device lookup failure"; return -ENXIO; } ms->mirror[mirror].offset = offset; return 0; } static int add_mirror_set(struct mirror_set *ms) { down_write(&_mirror_sets_lock); list_add_tail(&ms->list, &_mirror_sets); up_write(&_mirror_sets_lock); wake(); return 0; } static void del_mirror_set(struct mirror_set *ms) { down_write(&_mirror_sets_lock); list_del(&ms->list); up_write(&_mirror_sets_lock); } /* * Create dirty log: log_type #log_params <log_params> */ static struct dirty_log *create_dirty_log(struct dm_target *ti, unsigned int argc, char **argv, unsigned int *args_used) { unsigned int param_count; struct dirty_log *dl; if (argc < 2) { ti->error = "Insufficient mirror log arguments"; return NULL; } if (sscanf(argv[1], "%u", ¶m_count) != 1) { ti->error = "Invalid mirror log argument count"; return NULL; } *args_used = 2 + param_count; if (argc < *args_used) { ti->error = "Insufficient mirror log arguments"; return NULL; } dl = dm_create_dirty_log(argv[0], ti, param_count, argv + 2); if (!dl) { ti->error = "Error creating mirror dirty log"; return NULL; } if (!_check_region_size(ti, dl->type->get_region_size(dl))) { ti->error = "Invalid region size"; dm_destroy_dirty_log(dl); return NULL; } return dl; } /* * Construct a mirror mapping: * * log_type #log_params <log_params> * #mirrors [mirror_path offset]{2,} * * log_type is "core" or "disk" * #log_params is between 1 and 3 */ #define DM_IO_PAGES 64 static int mirror_ctr(struct dm_target *ti, unsigned int argc, char **argv) { int r; unsigned int nr_mirrors, m, args_used; struct mirror_set *ms; struct dirty_log *dl; dl = create_dirty_log(ti, argc, argv, &args_used); if (!dl) return -EINVAL; argv += args_used; argc -= args_used; if (!argc || sscanf(argv[0], "%u", &nr_mirrors) != 1 || nr_mirrors < 2 || nr_mirrors > KCOPYD_MAX_REGIONS + 1) { ti->error = "Invalid number of mirrors"; dm_destroy_dirty_log(dl); return -EINVAL; } argv++, argc--; if (argc != nr_mirrors * 2) { ti->error = "Wrong number of mirror arguments"; dm_destroy_dirty_log(dl); return -EINVAL; } ms = alloc_context(nr_mirrors, dl->type->get_region_size(dl), ti, dl); if (!ms) { dm_destroy_dirty_log(dl); return -ENOMEM; } /* Get the mirror parameter sets */ for (m = 0; m < nr_mirrors; m++) { r = get_mirror(ms, ti, m, argv); if (r) { free_context(ms, ti, m); return r; } argv += 2; argc -= 2; } ti->private = ms; ti->split_io = ms->rh.region_size; r = kcopyd_client_create(DM_IO_PAGES, &ms->kcopyd_client); if (r) { free_context(ms, ti, ms->nr_mirrors); return r; } add_mirror_set(ms); return 0; } static void mirror_dtr(struct dm_target *ti) { struct mirror_set *ms = (struct mirror_set *) ti->private; del_mirror_set(ms); kcopyd_client_destroy(ms->kcopyd_client); free_context(ms, ti, ms->nr_mirrors); } static void queue_bio(struct mirror_set *ms, struct bio *bio, int rw) { int should_wake = 0; struct bio_list *bl; bl = (rw == WRITE) ? &ms->writes : &ms->reads; spin_lock(&ms->lock); should_wake = !(bl->head); bio_list_add(bl, bio); spin_unlock(&ms->lock); if (should_wake) wake(); } /* * Mirror mapping function */ static int mirror_map(struct dm_target *ti, struct bio *bio, union map_info *map_context) { int r, rw = bio_rw(bio); struct mirror *m; struct mirror_set *ms = ti->private; map_context->ll = bio_to_region(&ms->rh, bio); if (rw == WRITE) { 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); if (r < 0 && r != -EWOULDBLOCK) return r; if (r == -EWOULDBLOCK) /* FIXME: ugly */ r = DM_MAPIO_SUBMITTED; /* * We don't want to fast track a recovery just for a read * ahead. So we just let it silently fail. * FIXME: get rid of this. */ if (!r && rw == READA) return -EIO; if (!r) { /* Pass this io over to the daemon */ queue_bio(ms, bio, rw); return DM_MAPIO_SUBMITTED; } m = choose_mirror(ms, bio->bi_sector); if (!m) return -EIO; map_bio(ms, m, bio); return DM_MAPIO_REMAPPED; } static int mirror_end_io(struct dm_target *ti, struct bio *bio, int error, union map_info *map_context) { int rw = bio_rw(bio); struct mirror_set *ms = (struct mirror_set *) ti->private; region_t region = map_context->ll; /* * We need to dec pending if this was a write. */ if (rw == WRITE) rh_dec(&ms->rh, region); return 0; } static void mirror_postsuspend(struct dm_target *ti) { struct mirror_set *ms = (struct mirror_set *) ti->private; struct dirty_log *log = ms->rh.log; rh_stop_recovery(&ms->rh); /* Wait for all I/O we generated to complete */ wait_event(_kmirrord_recovery_stopped, !atomic_read(&ms->rh.recovery_in_flight)); if (log->type->suspend && log->type->suspend(log)) /* FIXME: need better error handling */ DMWARN("log suspend failed"); } static void mirror_resume(struct dm_target *ti) { struct mirror_set *ms = (struct mirror_set *) ti->private; struct dirty_log *log = ms->rh.log; if (log->type->resume && log->type->resume(log)) /* FIXME: need better error handling */ DMWARN("log resume failed"); rh_start_recovery(&ms->rh); } static int mirror_status(struct dm_target *ti, status_type_t type, char *result, unsigned int maxlen) { unsigned int m, sz; struct mirror_set *ms = (struct mirror_set *) ti->private; sz = ms->rh.log->type->status(ms->rh.log, type, result, maxlen); switch (type) { case STATUSTYPE_INFO: DMEMIT("%d ", ms->nr_mirrors); for (m = 0; m < ms->nr_mirrors; m++) DMEMIT("%s ", ms->mirror[m].dev->name); DMEMIT("%llu/%llu", (unsigned long long)ms->rh.log->type-> get_sync_count(ms->rh.log), (unsigned long long)ms->nr_regions); break; case STATUSTYPE_TABLE: DMEMIT("%d", ms->nr_mirrors); for (m = 0; m < ms->nr_mirrors; m++) DMEMIT(" %s %llu", ms->mirror[m].dev->name, (unsigned long long)ms->mirror[m].offset); } return 0; } static struct target_type mirror_target = { .name = "mirror", .version = {1, 0, 2}, .module = THIS_MODULE, .ctr = mirror_ctr, .dtr = mirror_dtr, .map = mirror_map, .end_io = mirror_end_io, .postsuspend = mirror_postsuspend, .resume = mirror_resume, .status = mirror_status, }; static int __init dm_mirror_init(void) { int r; r = dm_dirty_log_init(); if (r) return r; _kmirrord_wq = create_singlethread_workqueue("kmirrord"); if (!_kmirrord_wq) { DMERR("couldn't start kmirrord"); dm_dirty_log_exit(); return r; } INIT_WORK(&_kmirrord_work, do_work); r = dm_register_target(&mirror_target); if (r < 0) { DMERR("%s: Failed to register mirror target", mirror_target.name); dm_dirty_log_exit(); destroy_workqueue(_kmirrord_wq); } return r; } static void __exit dm_mirror_exit(void) { int r; r = dm_unregister_target(&mirror_target); if (r < 0) DMERR("%s: unregister failed %d", mirror_target.name, r); destroy_workqueue(_kmirrord_wq); dm_dirty_log_exit(); } /* Module hooks */ module_init(dm_mirror_init); module_exit(dm_mirror_exit); MODULE_DESCRIPTION(DM_NAME " mirror target"); MODULE_AUTHOR("Joe Thornber"); MODULE_LICENSE("GPL");