| /* |
| * 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" |
| #define DM_IO_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 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. |
| *---------------------------------------------------------------*/ |
| 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; |
| uint64_t features; |
| |
| spinlock_t lock; /* protects the next two lists */ |
| struct bio_list reads; |
| struct bio_list writes; |
| |
| struct dm_io_client *io_client; |
| |
| /* recovery */ |
| region_t nr_regions; |
| int in_sync; |
| |
| struct mirror *default_mirror; /* Default mirror */ |
| |
| struct workqueue_struct *kmirrord_wq; |
| struct work_struct kmirrord_work; |
| |
| 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; |
| } |
| |
| static void wake(struct mirror_set *ms) |
| { |
| queue_work(ms->kmirrord_wq, &ms->kmirrord_work); |
| } |
| |
| /* 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); |
| 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_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); |
| 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(&rh->clean_regions, &clean); |
| INIT_LIST_HEAD(&rh->clean_regions); |
| |
| list_for_each_entry(reg, &clean, list) |
| 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); |
| } |
| |
| if (!list_empty(&rh->failed_recovered_regions)) { |
| list_splice(&rh->failed_recovered_regions, &failed_recovered); |
| INIT_LIST_HEAD(&rh->failed_recovered_regions); |
| |
| 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) |
| { |
| 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(rh->ms); |
| } |
| |
| /* |
| * 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; |
| } |
| |
| 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 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(rh->ms); |
| } |
| |
| /* |
| * 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; |
| |
| if (read_err) |
| /* Read error means the failure of default mirror. */ |
| DMERR_LIMIT("Unable to read primary mirror during recovery"); |
| |
| if (write_err) |
| DMERR_LIMIT("Write error during recovery (error = 0x%x)", |
| write_err); |
| |
| 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, 1)) |
| 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; |
| struct dm_io_request io_req = { |
| .bi_rw = WRITE, |
| .mem.type = DM_IO_BVEC, |
| .mem.ptr.bvec = bio->bi_io_vec + bio->bi_idx, |
| .notify.fn = write_callback, |
| .notify.context = bio, |
| .client = ms->io_client, |
| }; |
| |
| 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); |
| |
| (void) dm_io(&io_req, ms->nr_mirrors, io, NULL); |
| } |
| |
| 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 void do_mirror(struct work_struct *work) |
| { |
| struct mirror_set *ms =container_of(work, struct mirror_set, |
| kmirrord_work); |
| 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); |
| } |
| |
| /*----------------------------------------------------------------- |
| * 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]; |
| |
| ms->io_client = dm_io_client_create(DM_IO_PAGES); |
| if (IS_ERR(ms->io_client)) { |
| ti->error = "Error creating dm_io client"; |
| kfree(ms); |
| return NULL; |
| } |
| |
| 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); |
| |
| dm_io_client_destroy(ms->io_client); |
| 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; |
| } |
| |
| /* |
| * 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; |
| } |
| |
| static int parse_features(struct mirror_set *ms, unsigned argc, char **argv, |
| unsigned *args_used) |
| { |
| unsigned num_features; |
| struct dm_target *ti = ms->ti; |
| |
| *args_used = 0; |
| |
| if (!argc) |
| return 0; |
| |
| if (sscanf(argv[0], "%u", &num_features) != 1) { |
| ti->error = "Invalid number of features"; |
| return -EINVAL; |
| } |
| |
| argc--; |
| argv++; |
| (*args_used)++; |
| |
| if (num_features > argc) { |
| ti->error = "Not enough arguments to support feature count"; |
| return -EINVAL; |
| } |
| |
| if (!strcmp("handle_errors", argv[0])) |
| ms->features |= DM_RAID1_HANDLE_ERRORS; |
| else { |
| ti->error = "Unrecognised feature requested"; |
| return -EINVAL; |
| } |
| |
| (*args_used)++; |
| |
| return 0; |
| } |
| |
| /* |
| * Construct a mirror mapping: |
| * |
| * log_type #log_params <log_params> |
| * #mirrors [mirror_path offset]{2,} |
| * [#features <features>] |
| * |
| * log_type is "core" or "disk" |
| * #log_params is between 1 and 3 |
| * |
| * If present, features must be "handle_errors". |
| */ |
| 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 = "Too few 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; |
| |
| ms->kmirrord_wq = create_singlethread_workqueue("kmirrord"); |
| if (!ms->kmirrord_wq) { |
| DMERR("couldn't start kmirrord"); |
| free_context(ms, ti, m); |
| return -ENOMEM; |
| } |
| INIT_WORK(&ms->kmirrord_work, do_mirror); |
| |
| r = parse_features(ms, argc, argv, &args_used); |
| if (r) { |
| free_context(ms, ti, ms->nr_mirrors); |
| return r; |
| } |
| |
| argv += args_used; |
| argc -= args_used; |
| |
| /* |
| * Any read-balancing addition depends on the |
| * DM_RAID1_HANDLE_ERRORS flag being present. |
| * This is because the decision to balance depends |
| * on the sync state of a region. If the above |
| * flag is not present, we ignore errors; and |
| * the sync state may be inaccurate. |
| */ |
| |
| if (argc) { |
| ti->error = "Too many mirror arguments"; |
| free_context(ms, ti, ms->nr_mirrors); |
| return -EINVAL; |
| } |
| |
| r = kcopyd_client_create(DM_IO_PAGES, &ms->kcopyd_client); |
| if (r) { |
| destroy_workqueue(ms->kmirrord_wq); |
| free_context(ms, ti, ms->nr_mirrors); |
| return r; |
| } |
| |
| wake(ms); |
| return 0; |
| } |
| |
| static void mirror_dtr(struct dm_target *ti) |
| { |
| struct mirror_set *ms = (struct mirror_set *) ti->private; |
| |
| flush_workqueue(ms->kmirrord_wq); |
| kcopyd_client_destroy(ms->kcopyd_client); |
| destroy_workqueue(ms->kmirrord_wq); |
| 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(ms); |
| } |
| |
| /* |
| * 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 = 0; |
| struct mirror_set *ms = (struct mirror_set *) ti->private; |
| |
| 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 0 ", |
| (unsigned long long)ms->rh.log->type-> |
| get_sync_count(ms->rh.log), |
| (unsigned long long)ms->nr_regions); |
| |
| sz += ms->rh.log->type->status(ms->rh.log, type, result+sz, maxlen-sz); |
| |
| break; |
| |
| case STATUSTYPE_TABLE: |
| sz = ms->rh.log->type->status(ms->rh.log, type, result, maxlen); |
| |
| 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); |
| |
| if (ms->features & DM_RAID1_HANDLE_ERRORS) |
| DMEMIT(" 1 handle_errors"); |
| } |
| |
| return 0; |
| } |
| |
| static struct target_type mirror_target = { |
| .name = "mirror", |
| .version = {1, 0, 3}, |
| .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; |
| |
| r = dm_register_target(&mirror_target); |
| if (r < 0) { |
| DMERR("Failed to register mirror target"); |
| dm_dirty_log_exit(); |
| } |
| |
| return r; |
| } |
| |
| static void __exit dm_mirror_exit(void) |
| { |
| int r; |
| |
| r = dm_unregister_target(&mirror_target); |
| if (r < 0) |
| DMERR("unregister failed %d", r); |
| |
| 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"); |