dm raid1: separate region_hash interface part1
Separate the region hash code from raid1 so it can be shared by forthcoming
targets. Use BUG_ON() for failed async dm_io() calls.
Signed-off-by: Heinz Mauelshagen <hjm@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
diff --git a/drivers/md/Makefile b/drivers/md/Makefile
index f1ef33d..1c61580 100644
--- a/drivers/md/Makefile
+++ b/drivers/md/Makefile
@@ -34,7 +34,7 @@
obj-$(CONFIG_DM_DELAY) += dm-delay.o
obj-$(CONFIG_DM_MULTIPATH) += dm-multipath.o dm-round-robin.o
obj-$(CONFIG_DM_SNAPSHOT) += dm-snapshot.o
-obj-$(CONFIG_DM_MIRROR) += dm-mirror.o dm-log.o
+obj-$(CONFIG_DM_MIRROR) += dm-mirror.o dm-log.o dm-region-hash.o
obj-$(CONFIG_DM_ZERO) += dm-zero.o
quiet_cmd_unroll = UNROLL $@
diff --git a/drivers/md/dm-raid1.c b/drivers/md/dm-raid1.c
index f358853..92dcc06 100644
--- a/drivers/md/dm-raid1.c
+++ b/drivers/md/dm-raid1.c
@@ -1,31 +1,30 @@
/*
* Copyright (C) 2003 Sistina Software Limited.
+ * Copyright (C) 2005-2008 Red Hat, Inc. All rights reserved.
*
* This file is released under the GPL.
*/
-#include <linux/device-mapper.h>
-
#include "dm-bio-list.h"
#include "dm-bio-record.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)
@@ -33,87 +32,6 @@
static DECLARE_WAIT_QUEUE_HEAD(_kmirrord_recovery_stopped);
/*-----------------------------------------------------------------
- * Region hash
- *
- * The mirror splits itself up into discrete regions. Each
- * region can be in one of three states: clean, dirty,
- * nosync. There is no need to put clean regions in the hash.
- *
- * In addition to being present in the hash table a region _may_
- * be present on one of three lists.
- *
- * clean_regions: Regions on this list have no io pending to
- * them, they are in sync, we are no longer interested in them,
- * they are dull. rh_update_states() will remove them from the
- * hash table.
- *
- * quiesced_regions: These regions have been spun down, ready
- * for recovery. rh_recovery_start() will remove regions from
- * this list and hand them to kmirrord, which will schedule the
- * recovery io with kcopyd.
- *
- * recovered_regions: Regions that kcopyd has successfully
- * recovered. rh_update_states() will now schedule any delayed
- * io, up the recovery_count, and remove the region from the
- * hash.
- *
- * There are 2 locks:
- * A rw spin lock 'hash_lock' protects just the hash table,
- * this is never held in write mode from interrupt context,
- * which I believe means that we only have to disable irqs when
- * doing a write lock.
- *
- * An ordinary spin lock 'region_lock' that protects the three
- * lists in the region_hash, with the 'state', 'list' and
- * 'bhs_delayed' fields of the regions. This is used from irq
- * context, so all other uses will have to suspend local irqs.
- *---------------------------------------------------------------*/
-struct mirror_set;
-struct region_hash {
- struct mirror_set *ms;
- uint32_t region_size;
- unsigned region_shift;
-
- /* holds persistent region state */
- struct dm_dirty_log *log;
-
- /* hash table */
- rwlock_t hash_lock;
- mempool_t *region_pool;
- unsigned int mask;
- unsigned int nr_buckets;
- struct list_head *buckets;
-
- spinlock_t region_lock;
- atomic_t recovery_in_flight;
- struct semaphore recovery_count;
- struct list_head clean_regions;
- struct list_head quiesced_regions;
- struct list_head recovered_regions;
- struct list_head failed_recovered_regions;
-};
-
-enum {
- RH_CLEAN,
- RH_DIRTY,
- RH_NOSYNC,
- RH_RECOVERING
-};
-
-struct region {
- struct region_hash *rh; /* FIXME: can we get rid of this ? */
- region_t key;
- int state;
-
- struct list_head hash_list;
- struct list_head list;
-
- atomic_t pending;
- struct bio_list delayed_bios;
-};
-
-
-/*-----------------------------------------------------------------
* Mirror set structures.
*---------------------------------------------------------------*/
enum dm_raid1_error {
@@ -133,8 +51,7 @@
struct mirror_set {
struct dm_target *ti;
struct list_head list;
- struct region_hash rh;
- struct dm_kcopyd_client *kcopyd_client;
+
uint64_t features;
spinlock_t lock; /* protects the lists */
@@ -142,6 +59,8 @@
struct bio_list writes;
struct bio_list failures;
+ struct dm_region_hash *rh;
+ struct dm_kcopyd_client *kcopyd_client;
struct dm_io_client *io_client;
mempool_t *read_record_pool;
@@ -160,25 +79,14 @@
struct work_struct trigger_event;
- unsigned int nr_mirrors;
+ unsigned nr_mirrors;
struct mirror mirror[0];
};
-/*
- * Conversion fns
- */
-static inline region_t bio_to_region(struct region_hash *rh, struct bio *bio)
+static void wakeup_mirrord(void *context)
{
- return (bio->bi_sector - rh->ms->ti->begin) >> rh->region_shift;
-}
+ struct mirror_set *ms = context;
-static inline sector_t region_to_sector(struct region_hash *rh, region_t region)
-{
- return region << rh->region_shift;
-}
-
-static void wake(struct mirror_set *ms)
-{
queue_work(ms->kmirrord_wq, &ms->kmirrord_work);
}
@@ -187,7 +95,7 @@
struct mirror_set *ms = (struct mirror_set *) data;
clear_bit(0, &ms->timer_pending);
- wake(ms);
+ wakeup_mirrord(ms);
}
static void delayed_wake(struct mirror_set *ms)
@@ -201,473 +109,34 @@
add_timer(&ms->timer);
}
-/* FIXME move this */
-static void queue_bio(struct mirror_set *ms, struct bio *bio, int rw);
-
-#define MIN_REGIONS 64
-#define MAX_RECOVERY 1
-static int rh_init(struct region_hash *rh, struct mirror_set *ms,
- struct dm_dirty_log *log, uint32_t region_size,
- region_t nr_regions)
+static void wakeup_all_recovery_waiters(void *context)
{
- 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;
+ wake_up_all(&_kmirrord_recovery_stopped);
}
-static void rh_exit(struct region_hash *rh)
-{
- unsigned int h;
- struct region *reg, *nreg;
-
- BUG_ON(!list_empty(&rh->quiesced_regions));
- for (h = 0; h < rh->nr_buckets; h++) {
- list_for_each_entry_safe(reg, nreg, rh->buckets + h, hash_list) {
- BUG_ON(atomic_read(®->pending));
- mempool_free(reg, rh->region_pool);
- }
- }
-
- if (rh->log)
- dm_dirty_log_destroy(rh->log);
- if (rh->region_pool)
- mempool_destroy(rh->region_pool);
- vfree(rh->buckets);
-}
-
-#define RH_HASH_MULT 2654435387U
-
-static inline unsigned int rh_hash(struct region_hash *rh, region_t region)
-{
- return (unsigned int) ((region * RH_HASH_MULT) >> 12) & rh->mask;
-}
-
-static struct region *__rh_lookup(struct region_hash *rh, region_t region)
-{
- struct region *reg;
-
- list_for_each_entry (reg, rh->buckets + rh_hash(rh, region), hash_list)
- if (reg->key == region)
- return reg;
-
- return NULL;
-}
-
-static void __rh_insert(struct region_hash *rh, struct region *reg)
-{
- unsigned int h = rh_hash(rh, reg->key);
- list_add(®->hash_list, rh->buckets + h);
-}
-
-static struct region *__rh_alloc(struct region_hash *rh, region_t region)
-{
- struct region *reg, *nreg;
-
- read_unlock(&rh->hash_lock);
- nreg = mempool_alloc(rh->region_pool, GFP_ATOMIC);
- if (unlikely(!nreg))
- nreg = kmalloc(sizeof(struct region), GFP_NOIO);
- nreg->state = rh->log->type->in_sync(rh->log, region, 1) ?
- RH_CLEAN : RH_NOSYNC;
- nreg->rh = rh;
- nreg->key = region;
-
- INIT_LIST_HEAD(&nreg->list);
-
- atomic_set(&nreg->pending, 0);
- bio_list_init(&nreg->delayed_bios);
- write_lock_irq(&rh->hash_lock);
-
- reg = __rh_lookup(rh, region);
- if (reg)
- /* we lost the race */
- mempool_free(nreg, rh->region_pool);
-
- else {
- __rh_insert(rh, nreg);
- if (nreg->state == RH_CLEAN) {
- spin_lock(&rh->region_lock);
- list_add(&nreg->list, &rh->clean_regions);
- spin_unlock(&rh->region_lock);
- }
- reg = nreg;
- }
- write_unlock_irq(&rh->hash_lock);
- read_lock(&rh->hash_lock);
-
- return reg;
-}
-
-static inline struct region *__rh_find(struct region_hash *rh, region_t region)
-{
- struct region *reg;
-
- reg = __rh_lookup(rh, region);
- if (!reg)
- reg = __rh_alloc(rh, region);
-
- return reg;
-}
-
-static int rh_state(struct region_hash *rh, region_t region, int may_block)
-{
- int r;
- struct region *reg;
-
- read_lock(&rh->hash_lock);
- reg = __rh_lookup(rh, region);
- read_unlock(&rh->hash_lock);
-
- if (reg)
- return reg->state;
-
- /*
- * The region wasn't in the hash, so we fall back to the
- * dirty log.
- */
- r = rh->log->type->in_sync(rh->log, region, may_block);
-
- /*
- * Any error from the dirty log (eg. -EWOULDBLOCK) gets
- * taken as a RH_NOSYNC
- */
- return r == 1 ? RH_CLEAN : RH_NOSYNC;
-}
-
-static inline int rh_in_sync(struct region_hash *rh,
- region_t region, int may_block)
-{
- int state = rh_state(rh, region, may_block);
- return state == RH_CLEAN || state == RH_DIRTY;
-}
-
-static void dispatch_bios(struct mirror_set *ms, struct bio_list *bio_list)
-{
- struct bio *bio;
-
- while ((bio = bio_list_pop(bio_list))) {
- queue_bio(ms, bio, WRITE);
- }
-}
-
-static void complete_resync_work(struct region *reg, int success)
-{
- struct region_hash *rh = reg->rh;
-
- rh->log->type->set_region_sync(rh->log, reg->key, success);
-
- /*
- * Dispatch the bios before we call 'wake_up_all'.
- * This is important because if we are suspending,
- * we want to know that recovery is complete and
- * the work queue is flushed. If we wake_up_all
- * before we dispatch_bios (queue bios and call wake()),
- * then we risk suspending before the work queue
- * has been properly flushed.
- */
- dispatch_bios(rh->ms, ®->delayed_bios);
- if (atomic_dec_and_test(&rh->recovery_in_flight))
- wake_up_all(&_kmirrord_recovery_stopped);
- up(&rh->recovery_count);
-}
-
-static void rh_update_states(struct region_hash *rh)
-{
- struct region *reg, *next;
-
- LIST_HEAD(clean);
- LIST_HEAD(recovered);
- LIST_HEAD(failed_recovered);
-
- /*
- * Quickly grab the lists.
- */
- write_lock_irq(&rh->hash_lock);
- spin_lock(&rh->region_lock);
- if (!list_empty(&rh->clean_regions)) {
- list_splice_init(&rh->clean_regions, &clean);
-
- list_for_each_entry(reg, &clean, list)
- list_del(®->hash_list);
- }
-
- if (!list_empty(&rh->recovered_regions)) {
- list_splice_init(&rh->recovered_regions, &recovered);
-
- list_for_each_entry (reg, &recovered, list)
- list_del(®->hash_list);
- }
-
- if (!list_empty(&rh->failed_recovered_regions)) {
- list_splice_init(&rh->failed_recovered_regions,
- &failed_recovered);
-
- list_for_each_entry(reg, &failed_recovered, list)
- list_del(®->hash_list);
- }
-
- spin_unlock(&rh->region_lock);
- write_unlock_irq(&rh->hash_lock);
-
- /*
- * All the regions on the recovered and clean lists have
- * now been pulled out of the system, so no need to do
- * any more locking.
- */
- list_for_each_entry_safe (reg, next, &recovered, list) {
- rh->log->type->clear_region(rh->log, reg->key);
- complete_resync_work(reg, 1);
- mempool_free(reg, rh->region_pool);
- }
-
- list_for_each_entry_safe(reg, next, &failed_recovered, list) {
- complete_resync_work(reg, errors_handled(rh->ms) ? 0 : 1);
- mempool_free(reg, rh->region_pool);
- }
-
- list_for_each_entry_safe(reg, next, &clean, list) {
- rh->log->type->clear_region(rh->log, reg->key);
- mempool_free(reg, rh->region_pool);
- }
-
- rh->log->type->flush(rh->log);
-}
-
-static void rh_inc(struct region_hash *rh, region_t region)
-{
- struct region *reg;
-
- read_lock(&rh->hash_lock);
- reg = __rh_find(rh, region);
-
- spin_lock_irq(&rh->region_lock);
- atomic_inc(®->pending);
-
- if (reg->state == RH_CLEAN) {
- reg->state = RH_DIRTY;
- list_del_init(®->list); /* take off the clean list */
- spin_unlock_irq(&rh->region_lock);
-
- rh->log->type->mark_region(rh->log, reg->key);
- } else
- spin_unlock_irq(&rh->region_lock);
-
-
- read_unlock(&rh->hash_lock);
-}
-
-static void rh_inc_pending(struct region_hash *rh, struct bio_list *bios)
-{
- 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)
+static void queue_bio(struct mirror_set *ms, struct bio *bio, int rw)
{
unsigned long flags;
- struct region *reg;
int should_wake = 0;
+ struct bio_list *bl;
- read_lock(&rh->hash_lock);
- reg = __rh_lookup(rh, region);
- read_unlock(&rh->hash_lock);
-
- spin_lock_irqsave(&rh->region_lock, flags);
- if (atomic_dec_and_test(®->pending)) {
- /*
- * There is no pending I/O for this region.
- * We can move the region to corresponding list for next action.
- * At this point, the region is not yet connected to any list.
- *
- * If the state is RH_NOSYNC, the region should be kept off
- * from clean list.
- * The hash entry for RH_NOSYNC will remain in memory
- * until the region is recovered or the map is reloaded.
- */
-
- /* do nothing for RH_NOSYNC */
- if (reg->state == RH_RECOVERING) {
- list_add_tail(®->list, &rh->quiesced_regions);
- } else if (reg->state == RH_DIRTY) {
- reg->state = RH_CLEAN;
- list_add(®->list, &rh->clean_regions);
- }
- should_wake = 1;
- }
- spin_unlock_irqrestore(&rh->region_lock, flags);
+ bl = (rw == WRITE) ? &ms->writes : &ms->reads;
+ spin_lock_irqsave(&ms->lock, flags);
+ should_wake = !(bl->head);
+ bio_list_add(bl, bio);
+ spin_unlock_irqrestore(&ms->lock, flags);
if (should_wake)
- wake(rh->ms);
+ wakeup_mirrord(ms);
}
-/*
- * Starts quiescing a region in preparation for recovery.
- */
-static int __rh_recovery_prepare(struct region_hash *rh)
+static void dispatch_bios(void *context, struct bio_list *bio_list)
{
- int r;
- struct region *reg;
- region_t region;
+ struct mirror_set *ms = context;
+ struct bio *bio;
- /*
- * Ask the dirty log what's next.
- */
- r = rh->log->type->get_resync_work(rh->log, ®ion);
- if (r <= 0)
- return r;
-
- /*
- * Get this region, and start it quiescing by setting the
- * recovering flag.
- */
- read_lock(&rh->hash_lock);
- reg = __rh_find(rh, region);
- read_unlock(&rh->hash_lock);
-
- spin_lock_irq(&rh->region_lock);
- reg->state = RH_RECOVERING;
-
- /* Already quiesced ? */
- if (atomic_read(®->pending))
- list_del_init(®->list);
- else
- list_move(®->list, &rh->quiesced_regions);
-
- spin_unlock_irq(&rh->region_lock);
-
- return 1;
-}
-
-static void rh_recovery_prepare(struct region_hash *rh)
-{
- /* Extra reference to avoid race with rh_stop_recovery */
- atomic_inc(&rh->recovery_in_flight);
-
- while (!down_trylock(&rh->recovery_count)) {
- atomic_inc(&rh->recovery_in_flight);
- if (__rh_recovery_prepare(rh) <= 0) {
- atomic_dec(&rh->recovery_in_flight);
- up(&rh->recovery_count);
- break;
- }
- }
-
- /* Drop the extra reference */
- if (atomic_dec_and_test(&rh->recovery_in_flight))
- wake_up_all(&_kmirrord_recovery_stopped);
-}
-
-/*
- * Returns any quiesced regions.
- */
-static struct region *rh_recovery_start(struct region_hash *rh)
-{
- struct region *reg = NULL;
-
- spin_lock_irq(&rh->region_lock);
- if (!list_empty(&rh->quiesced_regions)) {
- reg = list_entry(rh->quiesced_regions.next,
- struct region, list);
- list_del_init(®->list); /* remove from the quiesced list */
- }
- spin_unlock_irq(&rh->region_lock);
-
- return reg;
-}
-
-static void rh_recovery_end(struct region *reg, int success)
-{
- struct region_hash *rh = reg->rh;
-
- spin_lock_irq(&rh->region_lock);
- if (success)
- list_add(®->list, ®->rh->recovered_regions);
- else {
- reg->state = RH_NOSYNC;
- list_add(®->list, ®->rh->failed_recovered_regions);
- }
- spin_unlock_irq(&rh->region_lock);
-
- wake(rh->ms);
-}
-
-static int rh_flush(struct region_hash *rh)
-{
- return rh->log->type->flush(rh->log);
-}
-
-static void rh_delay(struct region_hash *rh, struct bio *bio)
-{
- struct region *reg;
-
- read_lock(&rh->hash_lock);
- reg = __rh_find(rh, bio_to_region(rh, bio));
- bio_list_add(®->delayed_bios, bio);
- read_unlock(&rh->hash_lock);
-}
-
-static void rh_stop_recovery(struct region_hash *rh)
-{
- int i;
-
- /* wait for any recovering regions */
- for (i = 0; i < MAX_RECOVERY; i++)
- down(&rh->recovery_count);
-}
-
-static void rh_start_recovery(struct region_hash *rh)
-{
- int i;
-
- for (i = 0; i < MAX_RECOVERY; i++)
- up(&rh->recovery_count);
-
- wake(rh->ms);
+ while ((bio = bio_list_pop(bio_list)))
+ queue_bio(ms, bio, WRITE);
}
#define MIN_READ_RECORDS 20
@@ -777,8 +246,8 @@
static void recovery_complete(int read_err, unsigned long write_err,
void *context)
{
- struct region *reg = (struct region *)context;
- struct mirror_set *ms = reg->rh->ms;
+ struct dm_region *reg = context;
+ struct mirror_set *ms = dm_rh_region_context(reg);
int m, bit = 0;
if (read_err) {
@@ -804,31 +273,33 @@
}
}
- rh_recovery_end(reg, !(read_err || write_err));
+ dm_rh_recovery_end(reg, !(read_err || write_err));
}
-static int recover(struct mirror_set *ms, struct region *reg)
+static int recover(struct mirror_set *ms, struct dm_region *reg)
{
int r;
- unsigned int i;
+ unsigned i;
struct dm_io_region from, to[DM_KCOPYD_MAX_REGIONS], *dest;
struct mirror *m;
unsigned long flags = 0;
+ region_t key = dm_rh_get_region_key(reg);
+ sector_t region_size = dm_rh_get_region_size(ms->rh);
/* fill in the source */
m = get_default_mirror(ms);
from.bdev = m->dev->bdev;
- from.sector = m->offset + region_to_sector(reg->rh, reg->key);
- if (reg->key == (ms->nr_regions - 1)) {
+ from.sector = m->offset + dm_rh_region_to_sector(ms->rh, key);
+ if (key == (ms->nr_regions - 1)) {
/*
* The final region may be smaller than
* region_size.
*/
- from.count = ms->ti->len & (reg->rh->region_size - 1);
+ from.count = ms->ti->len & (region_size - 1);
if (!from.count)
- from.count = reg->rh->region_size;
+ from.count = region_size;
} else
- from.count = reg->rh->region_size;
+ from.count = region_size;
/* fill in the destinations */
for (i = 0, dest = to; i < ms->nr_mirrors; i++) {
@@ -837,7 +308,7 @@
m = ms->mirror + i;
dest->bdev = m->dev->bdev;
- dest->sector = m->offset + region_to_sector(reg->rh, reg->key);
+ dest->sector = m->offset + dm_rh_region_to_sector(ms->rh, key);
dest->count = from.count;
dest++;
}
@@ -854,22 +325,22 @@
static void do_recovery(struct mirror_set *ms)
{
+ struct dm_region *reg;
+ struct dm_dirty_log *log = dm_rh_dirty_log(ms->rh);
int r;
- struct region *reg;
- struct dm_dirty_log *log = ms->rh.log;
/*
* Start quiescing some regions.
*/
- rh_recovery_prepare(&ms->rh);
+ dm_rh_recovery_prepare(ms->rh);
/*
* Copy any already quiesced regions.
*/
- while ((reg = rh_recovery_start(&ms->rh))) {
+ while ((reg = dm_rh_recovery_start(ms->rh))) {
r = recover(ms, reg);
if (r)
- rh_recovery_end(reg, 0);
+ dm_rh_recovery_end(reg, 0);
}
/*
@@ -910,9 +381,10 @@
static int mirror_available(struct mirror_set *ms, struct bio *bio)
{
- region_t region = bio_to_region(&ms->rh, bio);
+ struct dm_dirty_log *log = dm_rh_dirty_log(ms->rh);
+ region_t region = dm_rh_bio_to_region(ms->rh, bio);
- if (ms->rh.log->type->in_sync(ms->rh.log, region, 0))
+ if (log->type->in_sync(log, region, 0))
return choose_mirror(ms, bio->bi_sector) ? 1 : 0;
return 0;
@@ -986,7 +458,14 @@
map_region(&io, m, bio);
bio_set_m(bio, m);
- (void) dm_io(&io_req, 1, &io, NULL);
+ BUG_ON(dm_io(&io_req, 1, &io, NULL));
+}
+
+static inline int region_in_sync(struct mirror_set *ms, region_t region,
+ int may_block)
+{
+ int state = dm_rh_get_state(ms->rh, region, may_block);
+ return state == DM_RH_CLEAN || state == DM_RH_DIRTY;
}
static void do_reads(struct mirror_set *ms, struct bio_list *reads)
@@ -996,13 +475,13 @@
struct mirror *m;
while ((bio = bio_list_pop(reads))) {
- region = bio_to_region(&ms->rh, bio);
+ region = dm_rh_bio_to_region(ms->rh, bio);
m = get_default_mirror(ms);
/*
* We can only read balance if the region is in sync.
*/
- if (likely(rh_in_sync(&ms->rh, region, 1)))
+ if (likely(region_in_sync(ms, region, 1)))
m = choose_mirror(ms, bio->bi_sector);
else if (m && atomic_read(&m->error_count))
m = NULL;
@@ -1025,57 +504,6 @@
* NOSYNC: increment pending, just write to the default mirror
*---------------------------------------------------------------*/
-/* __bio_mark_nosync
- * @ms
- * @bio
- * @done
- * @error
- *
- * The bio was written on some mirror(s) but failed on other mirror(s).
- * We can successfully endio the bio but should avoid the region being
- * marked clean by setting the state RH_NOSYNC.
- *
- * This function is _not_ safe in interrupt context!
- */
-static void __bio_mark_nosync(struct mirror_set *ms,
- struct bio *bio, unsigned done, int error)
-{
- unsigned long flags;
- struct region_hash *rh = &ms->rh;
- struct dm_dirty_log *log = ms->rh.log;
- struct region *reg;
- region_t region = bio_to_region(rh, bio);
- int recovering = 0;
-
- /* We must inform the log that the sync count has changed. */
- log->type->set_region_sync(log, region, 0);
- ms->in_sync = 0;
-
- read_lock(&rh->hash_lock);
- reg = __rh_find(rh, region);
- read_unlock(&rh->hash_lock);
-
- /* region hash entry should exist because write was in-flight */
- BUG_ON(!reg);
- BUG_ON(!list_empty(®->list));
-
- spin_lock_irqsave(&rh->region_lock, flags);
- /*
- * Possible cases:
- * 1) RH_DIRTY
- * 2) RH_NOSYNC: was dirty, other preceeding writes failed
- * 3) RH_RECOVERING: flushing pending writes
- * Either case, the region should have not been connected to list.
- */
- recovering = (reg->state == RH_RECOVERING);
- reg->state = RH_NOSYNC;
- BUG_ON(!list_empty(®->list));
- spin_unlock_irqrestore(&rh->region_lock, flags);
-
- bio_endio(bio, error);
- if (recovering)
- complete_resync_work(reg, 0);
-}
static void write_callback(unsigned long error, void *context)
{
@@ -1120,7 +548,7 @@
bio_list_add(&ms->failures, bio);
spin_unlock_irqrestore(&ms->lock, flags);
if (should_wake)
- wake(ms);
+ wakeup_mirrord(ms);
return;
}
out:
@@ -1150,7 +578,7 @@
*/
bio_set_m(bio, get_default_mirror(ms));
- (void) dm_io(&io_req, ms->nr_mirrors, io, NULL);
+ BUG_ON(dm_io(&io_req, ms->nr_mirrors, io, NULL));
}
static void do_writes(struct mirror_set *ms, struct bio_list *writes)
@@ -1170,18 +598,19 @@
bio_list_init(&recover);
while ((bio = bio_list_pop(writes))) {
- state = rh_state(&ms->rh, bio_to_region(&ms->rh, bio), 1);
+ state = dm_rh_get_state(ms->rh,
+ dm_rh_bio_to_region(ms->rh, bio), 1);
switch (state) {
- case RH_CLEAN:
- case RH_DIRTY:
+ case DM_RH_CLEAN:
+ case DM_RH_DIRTY:
this_list = &sync;
break;
- case RH_NOSYNC:
+ case DM_RH_NOSYNC:
this_list = &nosync;
break;
- case RH_RECOVERING:
+ case DM_RH_RECOVERING:
this_list = &recover;
break;
}
@@ -1194,9 +623,9 @@
* be written to (writes to recover regions are going to
* be delayed).
*/
- rh_inc_pending(&ms->rh, &sync);
- rh_inc_pending(&ms->rh, &nosync);
- ms->log_failure = rh_flush(&ms->rh) ? 1 : 0;
+ dm_rh_inc_pending(ms->rh, &sync);
+ dm_rh_inc_pending(ms->rh, &nosync);
+ ms->log_failure = dm_rh_flush(ms->rh) ? 1 : 0;
/*
* Dispatch io.
@@ -1205,13 +634,13 @@
spin_lock_irq(&ms->lock);
bio_list_merge(&ms->failures, &sync);
spin_unlock_irq(&ms->lock);
- wake(ms);
+ wakeup_mirrord(ms);
} else
while ((bio = bio_list_pop(&sync)))
do_write(ms, bio);
while ((bio = bio_list_pop(&recover)))
- rh_delay(&ms->rh, bio);
+ dm_rh_delay(ms->rh, bio);
while ((bio = bio_list_pop(&nosync))) {
map_bio(get_default_mirror(ms), bio);
@@ -1228,7 +657,8 @@
if (!ms->log_failure) {
while ((bio = bio_list_pop(failures)))
- __bio_mark_nosync(ms, bio, bio->bi_size, 0);
+ ms->in_sync = 0;
+ dm_rh_mark_nosync(ms->rh, bio, bio->bi_size, 0);
return;
}
@@ -1281,8 +711,8 @@
*---------------------------------------------------------------*/
static void do_mirror(struct work_struct *work)
{
- struct mirror_set *ms =container_of(work, struct mirror_set,
- kmirrord_work);
+ struct mirror_set *ms = container_of(work, struct mirror_set,
+ kmirrord_work);
struct bio_list reads, writes, failures;
unsigned long flags;
@@ -1295,7 +725,7 @@
bio_list_init(&ms->failures);
spin_unlock_irqrestore(&ms->lock, flags);
- rh_update_states(&ms->rh);
+ dm_rh_update_states(ms->rh, errors_handled(ms));
do_recovery(ms);
do_reads(ms, &reads);
do_writes(ms, &writes);
@@ -1304,7 +734,6 @@
dm_table_unplug_all(ms->ti->table);
}
-
/*-----------------------------------------------------------------
* Target functions
*---------------------------------------------------------------*/
@@ -1351,7 +780,11 @@
return NULL;
}
- if (rh_init(&ms->rh, ms, dl, region_size, ms->nr_regions)) {
+ ms->rh = dm_region_hash_create(ms, dispatch_bios, wakeup_mirrord,
+ wakeup_all_recovery_waiters,
+ ms->ti->begin, MAX_RECOVERY,
+ dl, region_size, ms->nr_regions);
+ if (IS_ERR(ms->rh)) {
ti->error = "Error creating dirty region hash";
dm_io_client_destroy(ms->io_client);
mempool_destroy(ms->read_record_pool);
@@ -1369,7 +802,7 @@
dm_put_device(ti, ms->mirror[m].dev);
dm_io_client_destroy(ms->io_client);
- rh_exit(&ms->rh);
+ dm_region_hash_destroy(ms->rh);
mempool_destroy(ms->read_record_pool);
kfree(ms);
}
@@ -1409,10 +842,10 @@
* Create dirty log: log_type #log_params <log_params>
*/
static struct dm_dirty_log *create_dirty_log(struct dm_target *ti,
- unsigned int argc, char **argv,
- unsigned int *args_used)
+ unsigned argc, char **argv,
+ unsigned *args_used)
{
- unsigned int param_count;
+ unsigned param_count;
struct dm_dirty_log *dl;
if (argc < 2) {
@@ -1543,7 +976,7 @@
}
ti->private = ms;
- ti->split_io = ms->rh.region_size;
+ ti->split_io = dm_rh_get_region_size(ms->rh);
ms->kmirrord_wq = create_singlethread_workqueue("kmirrord");
if (!ms->kmirrord_wq) {
@@ -1578,11 +1011,11 @@
goto err_destroy_wq;
}
- r = dm_kcopyd_client_create(DM_IO_PAGES, &ms->kcopyd_client);
+ r = dm_kcopyd_client_create(DM_KCOPYD_PAGES, &ms->kcopyd_client);
if (r)
goto err_destroy_wq;
- wake(ms);
+ wakeup_mirrord(ms);
return 0;
err_destroy_wq:
@@ -1603,22 +1036,6 @@
free_context(ms, ti, ms->nr_mirrors);
}
-static void queue_bio(struct mirror_set *ms, struct bio *bio, int rw)
-{
- unsigned long flags;
- int should_wake = 0;
- struct bio_list *bl;
-
- bl = (rw == WRITE) ? &ms->writes : &ms->reads;
- spin_lock_irqsave(&ms->lock, flags);
- should_wake = !(bl->head);
- bio_list_add(bl, bio);
- spin_unlock_irqrestore(&ms->lock, flags);
-
- if (should_wake)
- wake(ms);
-}
-
/*
* Mirror mapping function
*/
@@ -1629,16 +1046,16 @@
struct mirror *m;
struct mirror_set *ms = ti->private;
struct dm_raid1_read_record *read_record = NULL;
+ struct dm_dirty_log *log = dm_rh_dirty_log(ms->rh);
if (rw == WRITE) {
/* Save region for mirror_end_io() handler */
- map_context->ll = bio_to_region(&ms->rh, bio);
+ map_context->ll = dm_rh_bio_to_region(ms->rh, bio);
queue_bio(ms, bio, rw);
return DM_MAPIO_SUBMITTED;
}
- r = ms->rh.log->type->in_sync(ms->rh.log,
- bio_to_region(&ms->rh, bio), 0);
+ r = log->type->in_sync(log, dm_rh_bio_to_region(ms->rh, bio), 0);
if (r < 0 && r != -EWOULDBLOCK)
return r;
@@ -1686,7 +1103,7 @@
* We need to dec pending if this was a write.
*/
if (rw == WRITE) {
- rh_dec(&ms->rh, map_context->ll);
+ dm_rh_dec(ms->rh, map_context->ll);
return error;
}
@@ -1742,7 +1159,7 @@
static void mirror_presuspend(struct dm_target *ti)
{
struct mirror_set *ms = (struct mirror_set *) ti->private;
- struct dm_dirty_log *log = ms->rh.log;
+ struct dm_dirty_log *log = dm_rh_dirty_log(ms->rh);
atomic_set(&ms->suspend, 1);
@@ -1750,10 +1167,10 @@
* We must finish up all the work that we've
* generated (i.e. recovery work).
*/
- rh_stop_recovery(&ms->rh);
+ dm_rh_stop_recovery(ms->rh);
wait_event(_kmirrord_recovery_stopped,
- !atomic_read(&ms->rh.recovery_in_flight));
+ !dm_rh_recovery_in_flight(ms->rh));
if (log->type->presuspend && log->type->presuspend(log))
/* FIXME: need better error handling */
@@ -1771,7 +1188,7 @@
static void mirror_postsuspend(struct dm_target *ti)
{
struct mirror_set *ms = ti->private;
- struct dm_dirty_log *log = ms->rh.log;
+ struct dm_dirty_log *log = dm_rh_dirty_log(ms->rh);
if (log->type->postsuspend && log->type->postsuspend(log))
/* FIXME: need better error handling */
@@ -1781,13 +1198,13 @@
static void mirror_resume(struct dm_target *ti)
{
struct mirror_set *ms = ti->private;
- struct dm_dirty_log *log = ms->rh.log;
+ struct dm_dirty_log *log = dm_rh_dirty_log(ms->rh);
atomic_set(&ms->suspend, 0);
if (log->type->resume && log->type->resume(log))
/* FIXME: need better error handling */
DMWARN("log resume failed");
- rh_start_recovery(&ms->rh);
+ dm_rh_start_recovery(ms->rh);
}
/*
@@ -1819,7 +1236,7 @@
{
unsigned int m, sz = 0;
struct mirror_set *ms = (struct mirror_set *) ti->private;
- struct dm_dirty_log *log = ms->rh.log;
+ struct dm_dirty_log *log = dm_rh_dirty_log(ms->rh);
char buffer[ms->nr_mirrors + 1];
switch (type) {
@@ -1832,15 +1249,15 @@
buffer[m] = '\0';
DMEMIT("%llu/%llu 1 %s ",
- (unsigned long long)log->type->get_sync_count(ms->rh.log),
+ (unsigned long long)log->type->get_sync_count(log),
(unsigned long long)ms->nr_regions, buffer);
- sz += log->type->status(ms->rh.log, type, result+sz, maxlen-sz);
+ sz += log->type->status(log, type, result+sz, maxlen-sz);
break;
case STATUSTYPE_TABLE:
- sz = log->type->status(ms->rh.log, type, result, maxlen);
+ sz = log->type->status(log, type, result, maxlen);
DMEMIT("%d", ms->nr_mirrors);
for (m = 0; m < ms->nr_mirrors; m++)
diff --git a/drivers/md/dm-region-hash.c b/drivers/md/dm-region-hash.c
new file mode 100644
index 0000000..59f8d9d
--- /dev/null
+++ b/drivers/md/dm-region-hash.c
@@ -0,0 +1,704 @@
+/*
+ * Copyright (C) 2003 Sistina Software Limited.
+ * Copyright (C) 2004-2008 Red Hat, Inc. All rights reserved.
+ *
+ * This file is released under the GPL.
+ */
+
+#include <linux/dm-dirty-log.h>
+#include <linux/dm-region-hash.h>
+
+#include <linux/ctype.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/vmalloc.h>
+
+#include "dm.h"
+#include "dm-bio-list.h"
+
+#define DM_MSG_PREFIX "region hash"
+
+/*-----------------------------------------------------------------
+ * Region hash
+ *
+ * The mirror splits itself up into discrete regions. Each
+ * region can be in one of three states: clean, dirty,
+ * nosync. There is no need to put clean regions in the hash.
+ *
+ * In addition to being present in the hash table a region _may_
+ * be present on one of three lists.
+ *
+ * clean_regions: Regions on this list have no io pending to
+ * them, they are in sync, we are no longer interested in them,
+ * they are dull. dm_rh_update_states() will remove them from the
+ * hash table.
+ *
+ * quiesced_regions: These regions have been spun down, ready
+ * for recovery. rh_recovery_start() will remove regions from
+ * this list and hand them to kmirrord, which will schedule the
+ * recovery io with kcopyd.
+ *
+ * recovered_regions: Regions that kcopyd has successfully
+ * recovered. dm_rh_update_states() will now schedule any delayed
+ * io, up the recovery_count, and remove the region from the
+ * hash.
+ *
+ * There are 2 locks:
+ * A rw spin lock 'hash_lock' protects just the hash table,
+ * this is never held in write mode from interrupt context,
+ * which I believe means that we only have to disable irqs when
+ * doing a write lock.
+ *
+ * An ordinary spin lock 'region_lock' that protects the three
+ * lists in the region_hash, with the 'state', 'list' and
+ * 'delayed_bios' fields of the regions. This is used from irq
+ * context, so all other uses will have to suspend local irqs.
+ *---------------------------------------------------------------*/
+struct dm_region_hash {
+ uint32_t region_size;
+ unsigned region_shift;
+
+ /* holds persistent region state */
+ struct dm_dirty_log *log;
+
+ /* hash table */
+ rwlock_t hash_lock;
+ mempool_t *region_pool;
+ unsigned mask;
+ unsigned nr_buckets;
+ unsigned prime;
+ unsigned shift;
+ struct list_head *buckets;
+
+ unsigned max_recovery; /* Max # of regions to recover in parallel */
+
+ spinlock_t region_lock;
+ atomic_t recovery_in_flight;
+ struct semaphore recovery_count;
+ struct list_head clean_regions;
+ struct list_head quiesced_regions;
+ struct list_head recovered_regions;
+ struct list_head failed_recovered_regions;
+
+ void *context;
+ sector_t target_begin;
+
+ /* Callback function to schedule bios writes */
+ void (*dispatch_bios)(void *context, struct bio_list *bios);
+
+ /* Callback function to wakeup callers worker thread. */
+ void (*wakeup_workers)(void *context);
+
+ /* Callback function to wakeup callers recovery waiters. */
+ void (*wakeup_all_recovery_waiters)(void *context);
+};
+
+struct dm_region {
+ struct dm_region_hash *rh; /* FIXME: can we get rid of this ? */
+ region_t key;
+ int state;
+
+ struct list_head hash_list;
+ struct list_head list;
+
+ atomic_t pending;
+ struct bio_list delayed_bios;
+};
+
+/*
+ * Conversion fns
+ */
+static region_t dm_rh_sector_to_region(struct dm_region_hash *rh, sector_t sector)
+{
+ return sector >> rh->region_shift;
+}
+
+sector_t dm_rh_region_to_sector(struct dm_region_hash *rh, region_t region)
+{
+ return region << rh->region_shift;
+}
+EXPORT_SYMBOL_GPL(dm_rh_region_to_sector);
+
+region_t dm_rh_bio_to_region(struct dm_region_hash *rh, struct bio *bio)
+{
+ return dm_rh_sector_to_region(rh, bio->bi_sector - rh->target_begin);
+}
+EXPORT_SYMBOL_GPL(dm_rh_bio_to_region);
+
+void *dm_rh_region_context(struct dm_region *reg)
+{
+ return reg->rh->context;
+}
+EXPORT_SYMBOL_GPL(dm_rh_region_context);
+
+region_t dm_rh_get_region_key(struct dm_region *reg)
+{
+ return reg->key;
+}
+EXPORT_SYMBOL_GPL(dm_rh_get_region_key);
+
+sector_t dm_rh_get_region_size(struct dm_region_hash *rh)
+{
+ return rh->region_size;
+}
+EXPORT_SYMBOL_GPL(dm_rh_get_region_size);
+
+/*
+ * FIXME: shall we pass in a structure instead of all these args to
+ * dm_region_hash_create()????
+ */
+#define RH_HASH_MULT 2654435387U
+#define RH_HASH_SHIFT 12
+
+#define MIN_REGIONS 64
+struct dm_region_hash *dm_region_hash_create(
+ void *context, void (*dispatch_bios)(void *context,
+ struct bio_list *bios),
+ void (*wakeup_workers)(void *context),
+ void (*wakeup_all_recovery_waiters)(void *context),
+ sector_t target_begin, unsigned max_recovery,
+ struct dm_dirty_log *log, uint32_t region_size,
+ region_t nr_regions)
+{
+ struct dm_region_hash *rh;
+ unsigned nr_buckets, max_buckets;
+ size_t i;
+
+ /*
+ * Calculate a suitable number of buckets for our hash
+ * table.
+ */
+ max_buckets = nr_regions >> 6;
+ for (nr_buckets = 128u; nr_buckets < max_buckets; nr_buckets <<= 1)
+ ;
+ nr_buckets >>= 1;
+
+ rh = kmalloc(sizeof(*rh), GFP_KERNEL);
+ if (!rh) {
+ DMERR("unable to allocate region hash memory");
+ return ERR_PTR(-ENOMEM);
+ }
+
+ rh->context = context;
+ rh->dispatch_bios = dispatch_bios;
+ rh->wakeup_workers = wakeup_workers;
+ rh->wakeup_all_recovery_waiters = wakeup_all_recovery_waiters;
+ rh->target_begin = target_begin;
+ rh->max_recovery = max_recovery;
+ rh->log = log;
+ rh->region_size = region_size;
+ rh->region_shift = ffs(region_size) - 1;
+ rwlock_init(&rh->hash_lock);
+ rh->mask = nr_buckets - 1;
+ rh->nr_buckets = nr_buckets;
+
+ rh->shift = RH_HASH_SHIFT;
+ rh->prime = RH_HASH_MULT;
+
+ rh->buckets = vmalloc(nr_buckets * sizeof(*rh->buckets));
+ if (!rh->buckets) {
+ DMERR("unable to allocate region hash bucket memory");
+ kfree(rh);
+ return ERR_PTR(-ENOMEM);
+ }
+
+ for (i = 0; i < nr_buckets; i++)
+ INIT_LIST_HEAD(rh->buckets + i);
+
+ spin_lock_init(&rh->region_lock);
+ sema_init(&rh->recovery_count, 0);
+ atomic_set(&rh->recovery_in_flight, 0);
+ INIT_LIST_HEAD(&rh->clean_regions);
+ INIT_LIST_HEAD(&rh->quiesced_regions);
+ INIT_LIST_HEAD(&rh->recovered_regions);
+ INIT_LIST_HEAD(&rh->failed_recovered_regions);
+
+ rh->region_pool = mempool_create_kmalloc_pool(MIN_REGIONS,
+ sizeof(struct dm_region));
+ if (!rh->region_pool) {
+ vfree(rh->buckets);
+ kfree(rh);
+ rh = ERR_PTR(-ENOMEM);
+ }
+
+ return rh;
+}
+EXPORT_SYMBOL_GPL(dm_region_hash_create);
+
+void dm_region_hash_destroy(struct dm_region_hash *rh)
+{
+ unsigned h;
+ struct dm_region *reg, *nreg;
+
+ BUG_ON(!list_empty(&rh->quiesced_regions));
+ for (h = 0; h < rh->nr_buckets; h++) {
+ list_for_each_entry_safe(reg, nreg, rh->buckets + h,
+ hash_list) {
+ BUG_ON(atomic_read(®->pending));
+ mempool_free(reg, rh->region_pool);
+ }
+ }
+
+ if (rh->log)
+ dm_dirty_log_destroy(rh->log);
+
+ if (rh->region_pool)
+ mempool_destroy(rh->region_pool);
+
+ vfree(rh->buckets);
+ kfree(rh);
+}
+EXPORT_SYMBOL_GPL(dm_region_hash_destroy);
+
+struct dm_dirty_log *dm_rh_dirty_log(struct dm_region_hash *rh)
+{
+ return rh->log;
+}
+EXPORT_SYMBOL_GPL(dm_rh_dirty_log);
+
+static unsigned rh_hash(struct dm_region_hash *rh, region_t region)
+{
+ return (unsigned) ((region * rh->prime) >> rh->shift) & rh->mask;
+}
+
+static struct dm_region *__rh_lookup(struct dm_region_hash *rh, region_t region)
+{
+ struct dm_region *reg;
+ struct list_head *bucket = rh->buckets + rh_hash(rh, region);
+
+ list_for_each_entry(reg, bucket, hash_list)
+ if (reg->key == region)
+ return reg;
+
+ return NULL;
+}
+
+static void __rh_insert(struct dm_region_hash *rh, struct dm_region *reg)
+{
+ list_add(®->hash_list, rh->buckets + rh_hash(rh, reg->key));
+}
+
+static struct dm_region *__rh_alloc(struct dm_region_hash *rh, region_t region)
+{
+ struct dm_region *reg, *nreg;
+
+ nreg = mempool_alloc(rh->region_pool, GFP_ATOMIC);
+ if (unlikely(!nreg))
+ nreg = kmalloc(sizeof(*nreg), GFP_NOIO);
+
+ nreg->state = rh->log->type->in_sync(rh->log, region, 1) ?
+ DM_RH_CLEAN : DM_RH_NOSYNC;
+ nreg->rh = rh;
+ nreg->key = region;
+ INIT_LIST_HEAD(&nreg->list);
+ atomic_set(&nreg->pending, 0);
+ bio_list_init(&nreg->delayed_bios);
+
+ write_lock_irq(&rh->hash_lock);
+ reg = __rh_lookup(rh, region);
+ if (reg)
+ /* We lost the race. */
+ mempool_free(nreg, rh->region_pool);
+ else {
+ __rh_insert(rh, nreg);
+ if (nreg->state == DM_RH_CLEAN) {
+ spin_lock(&rh->region_lock);
+ list_add(&nreg->list, &rh->clean_regions);
+ spin_unlock(&rh->region_lock);
+ }
+
+ reg = nreg;
+ }
+ write_unlock_irq(&rh->hash_lock);
+
+ return reg;
+}
+
+static struct dm_region *__rh_find(struct dm_region_hash *rh, region_t region)
+{
+ struct dm_region *reg;
+
+ reg = __rh_lookup(rh, region);
+ if (!reg) {
+ read_unlock(&rh->hash_lock);
+ reg = __rh_alloc(rh, region);
+ read_lock(&rh->hash_lock);
+ }
+
+ return reg;
+}
+
+int dm_rh_get_state(struct dm_region_hash *rh, region_t region, int may_block)
+{
+ int r;
+ struct dm_region *reg;
+
+ read_lock(&rh->hash_lock);
+ reg = __rh_lookup(rh, region);
+ read_unlock(&rh->hash_lock);
+
+ if (reg)
+ return reg->state;
+
+ /*
+ * The region wasn't in the hash, so we fall back to the
+ * dirty log.
+ */
+ r = rh->log->type->in_sync(rh->log, region, may_block);
+
+ /*
+ * Any error from the dirty log (eg. -EWOULDBLOCK) gets
+ * taken as a DM_RH_NOSYNC
+ */
+ return r == 1 ? DM_RH_CLEAN : DM_RH_NOSYNC;
+}
+EXPORT_SYMBOL_GPL(dm_rh_get_state);
+
+static void complete_resync_work(struct dm_region *reg, int success)
+{
+ struct dm_region_hash *rh = reg->rh;
+
+ rh->log->type->set_region_sync(rh->log, reg->key, success);
+
+ /*
+ * Dispatch the bios before we call 'wake_up_all'.
+ * This is important because if we are suspending,
+ * we want to know that recovery is complete and
+ * the work queue is flushed. If we wake_up_all
+ * before we dispatch_bios (queue bios and call wake()),
+ * then we risk suspending before the work queue
+ * has been properly flushed.
+ */
+ rh->dispatch_bios(rh->context, ®->delayed_bios);
+ if (atomic_dec_and_test(&rh->recovery_in_flight))
+ rh->wakeup_all_recovery_waiters(rh->context);
+ up(&rh->recovery_count);
+}
+
+/* dm_rh_mark_nosync
+ * @ms
+ * @bio
+ * @done
+ * @error
+ *
+ * The bio was written on some mirror(s) but failed on other mirror(s).
+ * We can successfully endio the bio but should avoid the region being
+ * marked clean by setting the state DM_RH_NOSYNC.
+ *
+ * This function is _not_ safe in interrupt context!
+ */
+void dm_rh_mark_nosync(struct dm_region_hash *rh,
+ struct bio *bio, unsigned done, int error)
+{
+ unsigned long flags;
+ struct dm_dirty_log *log = rh->log;
+ struct dm_region *reg;
+ region_t region = dm_rh_bio_to_region(rh, bio);
+ int recovering = 0;
+
+ /* We must inform the log that the sync count has changed. */
+ log->type->set_region_sync(log, region, 0);
+
+ read_lock(&rh->hash_lock);
+ reg = __rh_find(rh, region);
+ read_unlock(&rh->hash_lock);
+
+ /* region hash entry should exist because write was in-flight */
+ BUG_ON(!reg);
+ BUG_ON(!list_empty(®->list));
+
+ spin_lock_irqsave(&rh->region_lock, flags);
+ /*
+ * Possible cases:
+ * 1) DM_RH_DIRTY
+ * 2) DM_RH_NOSYNC: was dirty, other preceeding writes failed
+ * 3) DM_RH_RECOVERING: flushing pending writes
+ * Either case, the region should have not been connected to list.
+ */
+ recovering = (reg->state == DM_RH_RECOVERING);
+ reg->state = DM_RH_NOSYNC;
+ BUG_ON(!list_empty(®->list));
+ spin_unlock_irqrestore(&rh->region_lock, flags);
+
+ bio_endio(bio, error);
+ if (recovering)
+ complete_resync_work(reg, 0);
+}
+EXPORT_SYMBOL_GPL(dm_rh_mark_nosync);
+
+void dm_rh_update_states(struct dm_region_hash *rh, int errors_handled)
+{
+ struct dm_region *reg, *next;
+
+ LIST_HEAD(clean);
+ LIST_HEAD(recovered);
+ LIST_HEAD(failed_recovered);
+
+ /*
+ * Quickly grab the lists.
+ */
+ write_lock_irq(&rh->hash_lock);
+ spin_lock(&rh->region_lock);
+ if (!list_empty(&rh->clean_regions)) {
+ list_splice_init(&rh->clean_regions, &clean);
+
+ list_for_each_entry(reg, &clean, list)
+ list_del(®->hash_list);
+ }
+
+ if (!list_empty(&rh->recovered_regions)) {
+ list_splice_init(&rh->recovered_regions, &recovered);
+
+ list_for_each_entry(reg, &recovered, list)
+ list_del(®->hash_list);
+ }
+
+ if (!list_empty(&rh->failed_recovered_regions)) {
+ list_splice_init(&rh->failed_recovered_regions,
+ &failed_recovered);
+
+ list_for_each_entry(reg, &failed_recovered, list)
+ list_del(®->hash_list);
+ }
+
+ spin_unlock(&rh->region_lock);
+ write_unlock_irq(&rh->hash_lock);
+
+ /*
+ * All the regions on the recovered and clean lists have
+ * now been pulled out of the system, so no need to do
+ * any more locking.
+ */
+ list_for_each_entry_safe(reg, next, &recovered, list) {
+ rh->log->type->clear_region(rh->log, reg->key);
+ complete_resync_work(reg, 1);
+ mempool_free(reg, rh->region_pool);
+ }
+
+ list_for_each_entry_safe(reg, next, &failed_recovered, list) {
+ complete_resync_work(reg, errors_handled ? 0 : 1);
+ mempool_free(reg, rh->region_pool);
+ }
+
+ list_for_each_entry_safe(reg, next, &clean, list) {
+ rh->log->type->clear_region(rh->log, reg->key);
+ mempool_free(reg, rh->region_pool);
+ }
+
+ rh->log->type->flush(rh->log);
+}
+EXPORT_SYMBOL_GPL(dm_rh_update_states);
+
+static void rh_inc(struct dm_region_hash *rh, region_t region)
+{
+ struct dm_region *reg;
+
+ read_lock(&rh->hash_lock);
+ reg = __rh_find(rh, region);
+
+ spin_lock_irq(&rh->region_lock);
+ atomic_inc(®->pending);
+
+ if (reg->state == DM_RH_CLEAN) {
+ reg->state = DM_RH_DIRTY;
+ list_del_init(®->list); /* take off the clean list */
+ spin_unlock_irq(&rh->region_lock);
+
+ rh->log->type->mark_region(rh->log, reg->key);
+ } else
+ spin_unlock_irq(&rh->region_lock);
+
+
+ read_unlock(&rh->hash_lock);
+}
+
+void dm_rh_inc_pending(struct dm_region_hash *rh, struct bio_list *bios)
+{
+ struct bio *bio;
+
+ for (bio = bios->head; bio; bio = bio->bi_next)
+ rh_inc(rh, dm_rh_bio_to_region(rh, bio));
+}
+EXPORT_SYMBOL_GPL(dm_rh_inc_pending);
+
+void dm_rh_dec(struct dm_region_hash *rh, region_t region)
+{
+ unsigned long flags;
+ struct dm_region *reg;
+ int should_wake = 0;
+
+ read_lock(&rh->hash_lock);
+ reg = __rh_lookup(rh, region);
+ read_unlock(&rh->hash_lock);
+
+ spin_lock_irqsave(&rh->region_lock, flags);
+ if (atomic_dec_and_test(®->pending)) {
+ /*
+ * There is no pending I/O for this region.
+ * We can move the region to corresponding list for next action.
+ * At this point, the region is not yet connected to any list.
+ *
+ * If the state is DM_RH_NOSYNC, the region should be kept off
+ * from clean list.
+ * The hash entry for DM_RH_NOSYNC will remain in memory
+ * until the region is recovered or the map is reloaded.
+ */
+
+ /* do nothing for DM_RH_NOSYNC */
+ if (reg->state == DM_RH_RECOVERING) {
+ list_add_tail(®->list, &rh->quiesced_regions);
+ } else if (reg->state == DM_RH_DIRTY) {
+ reg->state = DM_RH_CLEAN;
+ list_add(®->list, &rh->clean_regions);
+ }
+ should_wake = 1;
+ }
+ spin_unlock_irqrestore(&rh->region_lock, flags);
+
+ if (should_wake)
+ rh->wakeup_workers(rh->context);
+}
+EXPORT_SYMBOL_GPL(dm_rh_dec);
+
+/*
+ * Starts quiescing a region in preparation for recovery.
+ */
+static int __rh_recovery_prepare(struct dm_region_hash *rh)
+{
+ int r;
+ region_t region;
+ struct dm_region *reg;
+
+ /*
+ * Ask the dirty log what's next.
+ */
+ r = rh->log->type->get_resync_work(rh->log, ®ion);
+ if (r <= 0)
+ return r;
+
+ /*
+ * Get this region, and start it quiescing by setting the
+ * recovering flag.
+ */
+ read_lock(&rh->hash_lock);
+ reg = __rh_find(rh, region);
+ read_unlock(&rh->hash_lock);
+
+ spin_lock_irq(&rh->region_lock);
+ reg->state = DM_RH_RECOVERING;
+
+ /* Already quiesced ? */
+ if (atomic_read(®->pending))
+ list_del_init(®->list);
+ else
+ list_move(®->list, &rh->quiesced_regions);
+
+ spin_unlock_irq(&rh->region_lock);
+
+ return 1;
+}
+
+void dm_rh_recovery_prepare(struct dm_region_hash *rh)
+{
+ /* Extra reference to avoid race with dm_rh_stop_recovery */
+ atomic_inc(&rh->recovery_in_flight);
+
+ while (!down_trylock(&rh->recovery_count)) {
+ atomic_inc(&rh->recovery_in_flight);
+ if (__rh_recovery_prepare(rh) <= 0) {
+ atomic_dec(&rh->recovery_in_flight);
+ up(&rh->recovery_count);
+ break;
+ }
+ }
+
+ /* Drop the extra reference */
+ if (atomic_dec_and_test(&rh->recovery_in_flight))
+ rh->wakeup_all_recovery_waiters(rh->context);
+}
+EXPORT_SYMBOL_GPL(dm_rh_recovery_prepare);
+
+/*
+ * Returns any quiesced regions.
+ */
+struct dm_region *dm_rh_recovery_start(struct dm_region_hash *rh)
+{
+ struct dm_region *reg = NULL;
+
+ spin_lock_irq(&rh->region_lock);
+ if (!list_empty(&rh->quiesced_regions)) {
+ reg = list_entry(rh->quiesced_regions.next,
+ struct dm_region, list);
+ list_del_init(®->list); /* remove from the quiesced list */
+ }
+ spin_unlock_irq(&rh->region_lock);
+
+ return reg;
+}
+EXPORT_SYMBOL_GPL(dm_rh_recovery_start);
+
+void dm_rh_recovery_end(struct dm_region *reg, int success)
+{
+ struct dm_region_hash *rh = reg->rh;
+
+ spin_lock_irq(&rh->region_lock);
+ if (success)
+ list_add(®->list, ®->rh->recovered_regions);
+ else {
+ reg->state = DM_RH_NOSYNC;
+ list_add(®->list, ®->rh->failed_recovered_regions);
+ }
+ spin_unlock_irq(&rh->region_lock);
+
+ rh->wakeup_workers(rh->context);
+}
+EXPORT_SYMBOL_GPL(dm_rh_recovery_end);
+
+/* Return recovery in flight count. */
+int dm_rh_recovery_in_flight(struct dm_region_hash *rh)
+{
+ return atomic_read(&rh->recovery_in_flight);
+}
+EXPORT_SYMBOL_GPL(dm_rh_recovery_in_flight);
+
+int dm_rh_flush(struct dm_region_hash *rh)
+{
+ return rh->log->type->flush(rh->log);
+}
+EXPORT_SYMBOL_GPL(dm_rh_flush);
+
+void dm_rh_delay(struct dm_region_hash *rh, struct bio *bio)
+{
+ struct dm_region *reg;
+
+ read_lock(&rh->hash_lock);
+ reg = __rh_find(rh, dm_rh_bio_to_region(rh, bio));
+ bio_list_add(®->delayed_bios, bio);
+ read_unlock(&rh->hash_lock);
+}
+EXPORT_SYMBOL_GPL(dm_rh_delay);
+
+void dm_rh_stop_recovery(struct dm_region_hash *rh)
+{
+ int i;
+
+ /* wait for any recovering regions */
+ for (i = 0; i < rh->max_recovery; i++)
+ down(&rh->recovery_count);
+}
+EXPORT_SYMBOL_GPL(dm_rh_stop_recovery);
+
+void dm_rh_start_recovery(struct dm_region_hash *rh)
+{
+ int i;
+
+ for (i = 0; i < rh->max_recovery; i++)
+ up(&rh->recovery_count);
+
+ rh->wakeup_workers(rh->context);
+}
+EXPORT_SYMBOL_GPL(dm_rh_start_recovery);
+
+MODULE_DESCRIPTION(DM_NAME " region hash");
+MODULE_AUTHOR("Joe Thornber/Heinz Mauelshagen <dm-devel@redhat.com>");
+MODULE_LICENSE("GPL");
