nfsd4: shutdown callbacks on expiry
[safe/jmp/linux-2.6] / drivers / md / dm-raid1.c
index c4ce011..ddda531 100644 (file)
@@ -1,30 +1,29 @@
 /*
  * Copyright (C) 2003 Sistina Software Limited.
+ * Copyright (C) 2005-2008 Red Hat, Inc. All rights reserved.
  *
  * This file is released under the GPL.
  */
 
-#include "dm.h"
-#include "dm-bio-list.h"
 #include "dm-bio-record.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>
-#include <linux/log2.h>
-#include <linux/hardirq.h>
+#include <linux/device-mapper.h>
+#include <linux/dm-io.h>
+#include <linux/dm-dirty-log.h>
+#include <linux/dm-kcopyd.h>
+#include <linux/dm-region-hash.h>
 
 #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 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.
  *---------------------------------------------------------------*/
 enum dm_raid1_error {
        DM_RAID1_WRITE_ERROR,
+       DM_RAID1_FLUSH_ERROR,
        DM_RAID1_SYNC_ERROR,
        DM_RAID1_READ_ERROR
 };
@@ -132,15 +51,17 @@ struct mirror {
 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 lists */
        struct bio_list reads;
        struct bio_list writes;
        struct bio_list failures;
+       struct bio_list holds;  /* bios are waiting until suspend */
 
+       struct dm_region_hash *rh;
+       struct dm_kcopyd_client *kcopyd_client;
        struct dm_io_client *io_client;
        mempool_t *read_record_pool;
 
@@ -148,503 +69,76 @@ struct mirror_set {
        region_t nr_regions;
        int in_sync;
        int log_failure;
+       int leg_failure;
        atomic_t suspend;
 
        atomic_t default_mirror;        /* Default mirror */
 
        struct workqueue_struct *kmirrord_wq;
        struct work_struct kmirrord_work;
+       struct timer_list timer;
+       unsigned long timer_pending;
+
        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)
-{
-       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)
+static void wakeup_mirrord(void *context)
 {
-       return region << rh->region_shift;
-}
+       struct mirror_set *ms = context;
 
-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(&reg->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(&reg->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)
+static void delayed_wake_fn(unsigned long data)
 {
-       struct region_hash *rh = reg->rh;
-
-       rh->log->type->set_region_sync(rh->log, reg->key, success);
+       struct mirror_set *ms = (struct mirror_set *) data;
 
-       /*
-        * 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, &reg->delayed_bios);
-       if (atomic_dec_and_test(&rh->recovery_in_flight))
-               wake_up_all(&_kmirrord_recovery_stopped);
-       up(&rh->recovery_count);
+       clear_bit(0, &ms->timer_pending);
+       wakeup_mirrord(ms);
 }
 
-static void rh_update_states(struct region_hash *rh)
+static void delayed_wake(struct mirror_set *ms)
 {
-       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(&reg->hash_list);
-       }
-
-       if (!list_empty(&rh->recovered_regions)) {
-               list_splice_init(&rh->recovered_regions, &recovered);
-
-               list_for_each_entry (reg, &recovered, list)
-                       list_del(&reg->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(&reg->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(&reg->pending);
-
-       if (reg->state == RH_CLEAN) {
-               reg->state = RH_DIRTY;
-               list_del_init(&reg->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);
-
+       if (test_and_set_bit(0, &ms->timer_pending))
+               return;
 
-       read_unlock(&rh->hash_lock);
+       ms->timer.expires = jiffies + HZ / 5;
+       ms->timer.data = (unsigned long) ms;
+       ms->timer.function = delayed_wake_fn;
+       add_timer(&ms->timer);
 }
 
-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(&reg->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(&reg->list, &rh->quiesced_regions);
-               } else if (reg->state == RH_DIRTY) {
-                       reg->state = RH_CLEAN;
-                       list_add(&reg->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);
-}
-
-/*
- * 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, &region);
-       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(&reg->pending))
-               list_del_init(&reg->list);
-       else
-               list_move(&reg->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(&reg->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(&reg->list, &reg->rh->recovered_regions);
-       else {
-               reg->state = RH_NOSYNC;
-               list_add(&reg->list, &reg->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);
+               wakeup_mirrord(ms);
 }
 
-static void rh_delay(struct region_hash *rh, struct bio *bio)
+static void dispatch_bios(void *context, struct bio_list *bio_list)
 {
-       struct region *reg;
-
-       read_lock(&rh->hash_lock);
-       reg = __rh_find(rh, bio_to_region(rh, bio));
-       bio_list_add(&reg->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
@@ -653,6 +147,8 @@ struct dm_raid1_read_record {
        struct dm_bio_details details;
 };
 
+static struct kmem_cache *_dm_raid1_read_record_cache;
+
 /*
  * Every mirror should look like this one.
  */
@@ -686,6 +182,17 @@ static void set_default_mirror(struct mirror *m)
        atomic_set(&ms->default_mirror, m - m0);
 }
 
+static struct mirror *get_valid_mirror(struct mirror_set *ms)
+{
+       struct mirror *m;
+
+       for (m = ms->mirror; m < ms->mirror + ms->nr_mirrors; m++)
+               if (!atomic_read(&m->error_count))
+                       return m;
+
+       return NULL;
+}
+
 /* fail_mirror
  * @m: mirror device to fail
  * @error_type: one of the enum's, DM_RAID1_*_ERROR
@@ -705,8 +212,7 @@ static void fail_mirror(struct mirror *m, enum dm_raid1_error error_type)
        struct mirror_set *ms = m->ms;
        struct mirror *new;
 
-       if (!errors_handled(ms))
-               return;
+       ms->leg_failure = 1;
 
        /*
         * error_count is used for nothing more than a
@@ -718,6 +224,9 @@ static void fail_mirror(struct mirror *m, enum dm_raid1_error error_type)
        if (test_and_set_bit(error_type, &m->error_type))
                return;
 
+       if (!errors_handled(ms))
+               return;
+
        if (m != get_default_mirror(ms))
                goto out;
 
@@ -731,19 +240,50 @@ static void fail_mirror(struct mirror *m, enum dm_raid1_error error_type)
                goto out;
        }
 
-       for (new = ms->mirror; new < ms->mirror + ms->nr_mirrors; new++)
-               if (!atomic_read(&new->error_count)) {
-                       set_default_mirror(new);
-                       break;
-               }
-
-       if (unlikely(new == ms->mirror + ms->nr_mirrors))
+       new = get_valid_mirror(ms);
+       if (new)
+               set_default_mirror(new);
+       else
                DMWARN("All sides of mirror have failed.");
 
 out:
        schedule_work(&ms->trigger_event);
 }
 
+static int mirror_flush(struct dm_target *ti)
+{
+       struct mirror_set *ms = ti->private;
+       unsigned long error_bits;
+
+       unsigned int i;
+       struct dm_io_region io[ms->nr_mirrors];
+       struct mirror *m;
+       struct dm_io_request io_req = {
+               .bi_rw = WRITE_BARRIER,
+               .mem.type = DM_IO_KMEM,
+               .mem.ptr.bvec = NULL,
+               .client = ms->io_client,
+       };
+
+       for (i = 0, m = ms->mirror; i < ms->nr_mirrors; i++, m++) {
+               io[i].bdev = m->dev->bdev;
+               io[i].sector = 0;
+               io[i].count = 0;
+       }
+
+       error_bits = -1;
+       dm_io(&io_req, ms->nr_mirrors, io, &error_bits);
+       if (unlikely(error_bits != 0)) {
+               for (i = 0; i < ms->nr_mirrors; i++)
+                       if (test_bit(i, &error_bits))
+                               fail_mirror(ms->mirror + i,
+                                           DM_RAID1_FLUSH_ERROR);
+               return -EIO;
+       }
+
+       return 0;
+}
+
 /*-----------------------------------------------------------------
  * Recovery.
  *
@@ -754,8 +294,8 @@ 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) {
@@ -781,31 +321,33 @@ 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;
-       struct io_region from, to[KCOPYD_MAX_REGIONS], *dest;
+       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++) {
@@ -814,37 +356,39 @@ 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++;
        }
 
        /* 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);
+       if (!errors_handled(ms))
+               set_bit(DM_KCOPYD_IGNORE_ERROR, &flags);
+
+       r = dm_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)
 {
+       struct dm_region *reg;
+       struct dm_dirty_log *log = dm_rh_dirty_log(ms->rh);
        int r;
-       struct region *reg;
-       struct 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);
        }
 
        /*
@@ -885,9 +429,10 @@ 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;
@@ -898,6 +443,8 @@ static int mirror_available(struct mirror_set *ms, struct bio *bio)
  */
 static sector_t map_sector(struct mirror *m, struct bio *bio)
 {
+       if (unlikely(!bio->bi_size))
+               return 0;
        return m->offset + (bio->bi_sector - m->ms->ti->begin);
 }
 
@@ -907,7 +454,7 @@ static void map_bio(struct mirror *m, struct bio *bio)
        bio->bi_sector = map_sector(m, bio);
 }
 
-static void map_region(struct io_region *io, struct mirror *m,
+static void map_region(struct dm_io_region *io, struct mirror *m,
                       struct bio *bio)
 {
        io->bdev = m->dev->bdev;
@@ -915,6 +462,34 @@ static void map_region(struct io_region *io, struct mirror *m,
        io->count = bio->bi_size >> 9;
 }
 
+static void hold_bio(struct mirror_set *ms, struct bio *bio)
+{
+       /*
+        * Lock is required to avoid race condition during suspend
+        * process.
+        */
+       spin_lock_irq(&ms->lock);
+
+       if (atomic_read(&ms->suspend)) {
+               spin_unlock_irq(&ms->lock);
+
+               /*
+                * If device is suspended, complete the bio.
+                */
+               if (dm_noflush_suspending(ms->ti))
+                       bio_endio(bio, DM_ENDIO_REQUEUE);
+               else
+                       bio_endio(bio, -EIO);
+               return;
+       }
+
+       /*
+        * Hold bio until the suspend is complete.
+        */
+       bio_list_add(&ms->holds, bio);
+       spin_unlock_irq(&ms->lock);
+}
+
 /*-----------------------------------------------------------------
  * Reads
  *---------------------------------------------------------------*/
@@ -949,7 +524,7 @@ static void read_callback(unsigned long error, void *context)
 /* Asynchronous read. */
 static void read_async_bio(struct mirror *m, struct bio *bio)
 {
-       struct io_region io;
+       struct dm_io_region io;
        struct dm_io_request io_req = {
                .bi_rw = READ,
                .mem.type = DM_IO_BVEC,
@@ -961,7 +536,14 @@ 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)
@@ -971,13 +553,13 @@ 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;
@@ -1000,64 +582,12 @@ 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 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(&reg->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(&reg->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)
 {
        unsigned i, ret = 0;
        struct bio *bio = (struct bio *) context;
        struct mirror_set *ms;
-       int uptodate = 0;
        int should_wake = 0;
        unsigned long flags;
 
@@ -1070,45 +600,36 @@ static void write_callback(unsigned long error, void *context)
         * This way we handle both writes to SYNC and NOSYNC
         * regions with the same code.
         */
-       if (likely(!error))
-               goto out;
+       if (likely(!error)) {
+               bio_endio(bio, ret);
+               return;
+       }
 
        for (i = 0; i < ms->nr_mirrors; i++)
                if (test_bit(i, &error))
                        fail_mirror(ms->mirror + i, DM_RAID1_WRITE_ERROR);
-               else
-                       uptodate = 1;
 
-       if (unlikely(!uptodate)) {
-               DMERR("All replicated volumes dead, failing I/O");
-               /* None of the writes succeeded, fail the I/O. */
-               ret = -EIO;
-       } else if (errors_handled(ms)) {
-               /*
-                * Need to raise event.  Since raising
-                * events can block, we need to do it in
-                * the main thread.
-                */
-               spin_lock_irqsave(&ms->lock, flags);
-               if (!ms->failures.head)
-                       should_wake = 1;
-               bio_list_add(&ms->failures, bio);
-               spin_unlock_irqrestore(&ms->lock, flags);
-               if (should_wake)
-                       wake(ms);
-               return;
-       }
-out:
-       bio_endio(bio, ret);
+       /*
+        * Need to raise event.  Since raising
+        * events can block, we need to do it in
+        * the main thread.
+        */
+       spin_lock_irqsave(&ms->lock, flags);
+       if (!ms->failures.head)
+               should_wake = 1;
+       bio_list_add(&ms->failures, bio);
+       spin_unlock_irqrestore(&ms->lock, flags);
+       if (should_wake)
+               wakeup_mirrord(ms);
 }
 
 static void do_write(struct mirror_set *ms, struct bio *bio)
 {
        unsigned int i;
-       struct io_region io[ms->nr_mirrors], *dest = io;
+       struct dm_io_region io[ms->nr_mirrors], *dest = io;
        struct mirror *m;
        struct dm_io_request io_req = {
-               .bi_rw = WRITE,
+               .bi_rw = WRITE | (bio->bi_rw & WRITE_BARRIER),
                .mem.type = DM_IO_BVEC,
                .mem.ptr.bvec = bio->bi_io_vec + bio->bi_idx,
                .notify.fn = write_callback,
@@ -1125,7 +646,7 @@ 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)
@@ -1133,6 +654,9 @@ 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;
+       struct bio_list requeue;
+       struct dm_dirty_log *log = dm_rh_dirty_log(ms->rh);
+       region_t region;
 
        if (!writes->head)
                return;
@@ -1143,20 +667,34 @@ static void do_writes(struct mirror_set *ms, struct bio_list *writes)
        bio_list_init(&sync);
        bio_list_init(&nosync);
        bio_list_init(&recover);
+       bio_list_init(&requeue);
 
        while ((bio = bio_list_pop(writes))) {
-               state = rh_state(&ms->rh, bio_to_region(&ms->rh, bio), 1);
+               if (unlikely(bio_empty_barrier(bio))) {
+                       bio_list_add(&sync, bio);
+                       continue;
+               }
+
+               region = dm_rh_bio_to_region(ms->rh, bio);
+
+               if (log->type->is_remote_recovering &&
+                   log->type->is_remote_recovering(log, region)) {
+                       bio_list_add(&requeue, bio);
+                       continue;
+               }
+
+               state = dm_rh_get_state(ms->rh, region, 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;
                }
@@ -1165,31 +703,56 @@ static void do_writes(struct mirror_set *ms, struct bio_list *writes)
        }
 
        /*
+        * Add bios that are delayed due to remote recovery
+        * back on to the write queue
+        */
+       if (unlikely(requeue.head)) {
+               spin_lock_irq(&ms->lock);
+               bio_list_merge(&ms->writes, &requeue);
+               spin_unlock_irq(&ms->lock);
+               delayed_wake(ms);
+       }
+
+       /*
         * 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);
-       ms->log_failure = rh_flush(&ms->rh) ? 1 : 0;
+       dm_rh_inc_pending(ms->rh, &sync);
+       dm_rh_inc_pending(ms->rh, &nosync);
+
+       /*
+        * If the flush fails on a previous call and succeeds here,
+        * we must not reset the log_failure variable.  We need
+        * userspace interaction to do that.
+        */
+       ms->log_failure = dm_rh_flush(ms->rh) ? 1 : ms->log_failure;
 
        /*
         * Dispatch io.
         */
-       if (unlikely(ms->log_failure)) {
+       if (unlikely(ms->log_failure) && errors_handled(ms)) {
                spin_lock_irq(&ms->lock);
                bio_list_merge(&ms->failures, &sync);
                spin_unlock_irq(&ms->lock);
+               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);
-               generic_make_request(bio);
+               if (unlikely(ms->leg_failure) && errors_handled(ms)) {
+                       spin_lock_irq(&ms->lock);
+                       bio_list_add(&ms->failures, bio);
+                       spin_unlock_irq(&ms->lock);
+                       wakeup_mirrord(ms);
+               } else {
+                       map_bio(get_default_mirror(ms), bio);
+                       generic_make_request(bio);
+               }
        }
 }
 
@@ -1197,18 +760,12 @@ static void do_failures(struct mirror_set *ms, struct bio_list *failures)
 {
        struct bio *bio;
 
-       if (!failures->head)
+       if (likely(!failures->head))
                return;
 
-       if (!ms->log_failure) {
-               while ((bio = bio_list_pop(failures)))
-                       __bio_mark_nosync(ms, bio, bio->bi_size, 0);
-               return;
-       }
-
        /*
         * If the log has failed, unattempted writes are being
-        * put on the failures list.  We can't issue those writes
+        * put on the holds list.  We can't issue those writes
         * until a log has been marked, so we must store them.
         *
         * If a 'noflush' suspend is in progress, we can requeue
@@ -1223,23 +780,27 @@ static void do_failures(struct mirror_set *ms, struct bio_list *failures)
         * for us to treat them the same and requeue them
         * as well.
         */
-       if (dm_noflush_suspending(ms->ti)) {
-               while ((bio = bio_list_pop(failures)))
-                       bio_endio(bio, DM_ENDIO_REQUEUE);
-               return;
-       }
+       while ((bio = bio_list_pop(failures))) {
+               if (!ms->log_failure) {
+                       ms->in_sync = 0;
+                       dm_rh_mark_nosync(ms->rh, bio);
+               }
 
-       if (atomic_read(&ms->suspend)) {
-               while ((bio = bio_list_pop(failures)))
+               /*
+                * If all the legs are dead, fail the I/O.
+                * If we have been told to handle errors, hold the bio
+                * and wait for userspace to deal with the problem.
+                * Otherwise pretend that the I/O succeeded. (This would
+                * be wrong if the failed leg returned after reboot and
+                * got replicated back to the good legs.)
+                */
+               if (!get_valid_mirror(ms))
                        bio_endio(bio, -EIO);
-               return;
+               else if (errors_handled(ms))
+                       hold_bio(ms, bio);
+               else
+                       bio_endio(bio, 0);
        }
-
-       spin_lock_irq(&ms->lock);
-       bio_list_merge(&ms->failures, failures);
-       spin_unlock_irq(&ms->lock);
-
-       wake(ms);
 }
 
 static void trigger_event(struct work_struct *work)
@@ -1253,10 +814,10 @@ static void trigger_event(struct work_struct *work)
 /*-----------------------------------------------------------------
  * kmirrord
  *---------------------------------------------------------------*/
-static int _do_mirror(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;
 
@@ -1269,46 +830,26 @@ static int _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);
        do_failures(ms, &failures);
 
-       return (ms->failures.head) ? 1 : 0;
-}
-
-static void do_mirror(struct work_struct *work)
-{
-       /*
-        * If _do_mirror returns 1, we give it
-        * another shot.  This helps for cases like
-        * 'suspend' where we call flush_workqueue
-        * and expect all work to be finished.  If
-        * a failure happens during a suspend, we
-        * couldn't issue a 'wake' because it would
-        * not be honored.  Therefore, we return '1'
-        * from _do_mirror, and retry here.
-        */
-       while (_do_mirror(work))
-               schedule();
+       dm_table_unplug_all(ms->ti->table);
 }
 
-
 /*-----------------------------------------------------------------
  * Target functions
  *---------------------------------------------------------------*/
 static struct mirror_set *alloc_context(unsigned int nr_mirrors,
                                        uint32_t region_size,
                                        struct dm_target *ti,
-                                       struct dirty_log *dl)
+                                       struct dm_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 = kzalloc(len, GFP_KERNEL);
@@ -1318,18 +859,23 @@ static struct mirror_set *alloc_context(unsigned int nr_mirrors,
        }
 
        spin_lock_init(&ms->lock);
+       bio_list_init(&ms->reads);
+       bio_list_init(&ms->writes);
+       bio_list_init(&ms->failures);
+       bio_list_init(&ms->holds);
 
        ms->ti = ti;
        ms->nr_mirrors = nr_mirrors;
        ms->nr_regions = dm_sector_div_up(ti->len, region_size);
        ms->in_sync = 0;
        ms->log_failure = 0;
+       ms->leg_failure = 0;
        atomic_set(&ms->suspend, 0);
        atomic_set(&ms->default_mirror, DEFAULT_MIRROR);
 
-       len = sizeof(struct dm_raid1_read_record);
-       ms->read_record_pool = mempool_create_kmalloc_pool(MIN_READ_RECORDS,
-                                                          len);
+       ms->read_record_pool = mempool_create_slab_pool(MIN_READ_RECORDS,
+                                               _dm_raid1_read_record_cache);
+
        if (!ms->read_record_pool) {
                ti->error = "Error creating mirror read_record_pool";
                kfree(ms);
@@ -1344,7 +890,11 @@ 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);
@@ -1362,17 +912,11 @@ 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);
 }
 
-static inline int _check_region_size(struct dm_target *ti, uint32_t size)
-{
-       return !(size % (PAGE_SIZE >> 9) || !is_power_of_2(size) ||
-                size > ti->len);
-}
-
 static int get_mirror(struct mirror_set *ms, struct dm_target *ti,
                      unsigned int mirror, char **argv)
 {
@@ -1383,8 +927,7 @@ static int get_mirror(struct mirror_set *ms, struct dm_target *ti,
                return -EINVAL;
        }
 
-       if (dm_get_device(ti, argv[0], offset, ti->len,
-                         dm_table_get_mode(ti->table),
+       if (dm_get_device(ti, argv[0], dm_table_get_mode(ti->table),
                          &ms->mirror[mirror].dev)) {
                ti->error = "Device lookup failure";
                return -ENXIO;
@@ -1401,12 +944,12 @@ static int get_mirror(struct mirror_set *ms, struct dm_target *ti,
 /*
  * 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)
+static struct dm_dirty_log *create_dirty_log(struct dm_target *ti,
+                                            unsigned argc, char **argv,
+                                            unsigned *args_used)
 {
-       unsigned int param_count;
-       struct dirty_log *dl;
+       unsigned param_count;
+       struct dm_dirty_log *dl;
 
        if (argc < 2) {
                ti->error = "Insufficient mirror log arguments";
@@ -1425,18 +968,13 @@ static struct dirty_log *create_dirty_log(struct dm_target *ti,
                return NULL;
        }
 
-       dl = dm_create_dirty_log(argv[0], ti, param_count, argv + 2);
+       dl = dm_dirty_log_create(argv[0], ti, mirror_flush, 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;
 }
 
@@ -1494,7 +1032,7 @@ 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;
+       struct dm_dirty_log *dl;
 
        dl = create_dirty_log(ti, argc, argv, &args_used);
        if (!dl)
@@ -1504,9 +1042,9 @@ static int mirror_ctr(struct dm_target *ti, unsigned int argc, char **argv)
        argc -= args_used;
 
        if (!argc || sscanf(argv[0], "%u", &nr_mirrors) != 1 ||
-           nr_mirrors < 2 || nr_mirrors > KCOPYD_MAX_REGIONS + 1) {
+           nr_mirrors < 2 || nr_mirrors > DM_KCOPYD_MAX_REGIONS + 1) {
                ti->error = "Invalid number of mirrors";
-               dm_destroy_dirty_log(dl);
+               dm_dirty_log_destroy(dl);
                return -EINVAL;
        }
 
@@ -1514,13 +1052,13 @@ static int mirror_ctr(struct dm_target *ti, unsigned int argc, char **argv)
 
        if (argc < nr_mirrors * 2) {
                ti->error = "Too few mirror arguments";
-               dm_destroy_dirty_log(dl);
+               dm_dirty_log_destroy(dl);
                return -EINVAL;
        }
 
        ms = alloc_context(nr_mirrors, dl->type->get_region_size(dl), ti, dl);
        if (!ms) {
-               dm_destroy_dirty_log(dl);
+               dm_dirty_log_destroy(dl);
                return -ENOMEM;
        }
 
@@ -1536,7 +1074,8 @@ 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);
+       ti->num_flush_requests = 1;
 
        ms->kmirrord_wq = create_singlethread_workqueue("kmirrord");
        if (!ms->kmirrord_wq) {
@@ -1545,6 +1084,8 @@ static int mirror_ctr(struct dm_target *ti, unsigned int argc, char **argv)
                goto err_free_context;
        }
        INIT_WORK(&ms->kmirrord_work, do_mirror);
+       init_timer(&ms->timer);
+       ms->timer_pending = 0;
        INIT_WORK(&ms->trigger_event, trigger_event);
 
        r = parse_features(ms, argc, argv, &args_used);
@@ -1569,11 +1110,11 @@ static int mirror_ctr(struct dm_target *ti, unsigned int argc, char **argv)
                goto err_destroy_wq;
        }
 
-       r = 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:
@@ -1587,28 +1128,14 @@ static void mirror_dtr(struct dm_target *ti)
 {
        struct mirror_set *ms = (struct mirror_set *) ti->private;
 
+       del_timer_sync(&ms->timer);
        flush_workqueue(ms->kmirrord_wq);
-       kcopyd_client_destroy(ms->kcopyd_client);
+       flush_scheduled_work();
+       dm_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)
-{
-       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
  */
@@ -1619,16 +1146,16 @@ 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;
 
@@ -1676,14 +1203,15 @@ 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);
+               if (likely(!bio_empty_barrier(bio)))
+                       dm_rh_dec(ms->rh, map_context->ll);
                return error;
        }
 
        if (error == -EOPNOTSUPP)
                goto out;
 
-       if ((error == -EWOULDBLOCK) && bio_rw_ahead(bio))
+       if ((error == -EWOULDBLOCK) && bio_rw_flagged(bio, BIO_RW_AHEAD))
                goto out;
 
        if (unlikely(error)) {
@@ -1732,18 +1260,35 @@ out:
 static void mirror_presuspend(struct dm_target *ti)
 {
        struct mirror_set *ms = (struct mirror_set *) ti->private;
-       struct dirty_log *log = ms->rh.log;
+       struct dm_dirty_log *log = dm_rh_dirty_log(ms->rh);
+
+       struct bio_list holds;
+       struct bio *bio;
 
        atomic_set(&ms->suspend, 1);
 
        /*
+        * Process bios in the hold list to start recovery waiting
+        * for bios in the hold list. After the process, no bio has
+        * a chance to be added in the hold list because ms->suspend
+        * is set.
+        */
+       spin_lock_irq(&ms->lock);
+       holds = ms->holds;
+       bio_list_init(&ms->holds);
+       spin_unlock_irq(&ms->lock);
+
+       while ((bio = bio_list_pop(&holds)))
+               hold_bio(ms, bio);
+
+       /*
         * 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 */
@@ -1761,7 +1306,7 @@ static void mirror_presuspend(struct dm_target *ti)
 static void mirror_postsuspend(struct dm_target *ti)
 {
        struct mirror_set *ms = ti->private;
-       struct 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 */
@@ -1771,13 +1316,13 @@ static void mirror_postsuspend(struct dm_target *ti)
 static void mirror_resume(struct dm_target *ti)
 {
        struct mirror_set *ms = ti->private;
-       struct 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);
 }
 
 /*
@@ -1798,7 +1343,8 @@ static char device_status_char(struct mirror *m)
        if (!atomic_read(&(m->error_count)))
                return 'A';
 
-       return (test_bit(DM_RAID1_WRITE_ERROR, &(m->error_type))) ? 'D' :
+       return (test_bit(DM_RAID1_FLUSH_ERROR, &(m->error_type))) ? 'F' :
+               (test_bit(DM_RAID1_WRITE_ERROR, &(m->error_type))) ? 'D' :
                (test_bit(DM_RAID1_SYNC_ERROR, &(m->error_type))) ? 'S' :
                (test_bit(DM_RAID1_READ_ERROR, &(m->error_type))) ? 'R' : 'U';
 }
@@ -1809,7 +1355,7 @@ 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 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) {
@@ -1822,15 +1368,15 @@ 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++)
@@ -1844,9 +1390,23 @@ static int mirror_status(struct dm_target *ti, status_type_t type,
        return 0;
 }
 
+static int mirror_iterate_devices(struct dm_target *ti,
+                                 iterate_devices_callout_fn fn, void *data)
+{
+       struct mirror_set *ms = ti->private;
+       int ret = 0;
+       unsigned i;
+
+       for (i = 0; !ret && i < ms->nr_mirrors; i++)
+               ret = fn(ti, ms->mirror[i].dev,
+                        ms->mirror[i].offset, ti->len, data);
+
+       return ret;
+}
+
 static struct target_type mirror_target = {
        .name    = "mirror",
-       .version = {1, 0, 20},
+       .version = {1, 12, 0},
        .module  = THIS_MODULE,
        .ctr     = mirror_ctr,
        .dtr     = mirror_dtr,
@@ -1856,26 +1416,38 @@ static struct target_type mirror_target = {
        .postsuspend = mirror_postsuspend,
        .resume  = mirror_resume,
        .status  = mirror_status,
+       .iterate_devices = mirror_iterate_devices,
 };
 
 static int __init dm_mirror_init(void)
 {
        int r;
 
+       _dm_raid1_read_record_cache = KMEM_CACHE(dm_raid1_read_record, 0);
+       if (!_dm_raid1_read_record_cache) {
+               DMERR("Can't allocate dm_raid1_read_record cache");
+               r = -ENOMEM;
+               goto bad_cache;
+       }
+
        r = dm_register_target(&mirror_target);
-       if (r < 0)
+       if (r < 0) {
                DMERR("Failed to register mirror target");
+               goto bad_target;
+       }
+
+       return 0;
 
+bad_target:
+       kmem_cache_destroy(_dm_raid1_read_record_cache);
+bad_cache:
        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_unregister_target(&mirror_target);
+       kmem_cache_destroy(_dm_raid1_read_record_cache);
 }
 
 /* Module hooks */