Skip to content

L
linux
Commit 1f965b19 authored by Heinz Mauelshagen's avatar Heinz Mauelshagen Committed by Alasdair G Kergon
Browse files
Options

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: default avatarHeinz Mauelshagen <hjm@redhat.com>
Signed-off-by: default avatarAlasdair G Kergon <agk@redhat.com>
parent f3e1d26e
Show whitespace changes
Inline Side-by-side
Showing with 912 additions and 687 deletions
drivers/md/Makefile
View file @ 1f965b19
......@@ -34,7 +34,7 @@ obj-$(CONFIG_DM_CRYPT) += dm-crypt.o
obj-$(CONFIG_DM_DELAY) += dm-delay.o
obj-$(CONFIG_DM_MULTIPATH) += dm-multipath.o dm-round-robin.o
obj-$(CONFIG_DM_SNAPSHOT) += dm-snapshot.o
obj-$(CONFIG_DM_MIRROR) += dm-mirror.o dm-log.o
obj-$(CONFIG_DM_MIRROR) += dm-mirror.o dm-log.o dm-region-hash.o
obj-$(CONFIG_DM_ZERO) += dm-zero.o
quiet_cmd_unroll = UNROLL $@
......
drivers/md/dm-raid1.c
View file @ 1f965b19
/*
* 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)
static DECLARE_WAIT_QUEUE_HEAD(_kmirrord_recovery_stopped);
/*-----------------------------------------------------------------
* Region hash
*
* The mirror splits itself up into discrete regions. Each
* region can be in one of three states: clean, dirty,
* nosync. There is no need to put clean regions in the hash.
*
* In addition to being present in the hash table a region _may_
* be present on one of three lists.
*
* clean_regions: Regions on this list have no io pending to
* them, they are in sync, we are no longer interested in them,
* they are dull. rh_update_states() will remove them from the
* hash table.
*
* quiesced_regions: These regions have been spun down, ready
* for recovery. rh_recovery_start() will remove regions from
* this list and hand them to kmirrord, which will schedule the
* recovery io with kcopyd.
*
* recovered_regions: Regions that kcopyd has successfully
* recovered. rh_update_states() will now schedule any delayed
* io, up the recovery_count, and remove the region from the
* hash.
*
* There are 2 locks:
* A rw spin lock 'hash_lock' protects just the hash table,
* this is never held in write mode from interrupt context,
* which I believe means that we only have to disable irqs when
* doing a write lock.
*
* An ordinary spin lock 'region_lock' that protects the three
* lists in the region_hash, with the 'state', 'list' and
* 'bhs_delayed' fields of the regions. This is used from irq
* context, so all other uses will have to suspend local irqs.
*---------------------------------------------------------------*/
struct mirror_set;
struct region_hash {
struct mirror_set *ms;
uint32_t region_size;
unsigned region_shift;
/* holds persistent region state */
struct dm_dirty_log *log;
/* hash table */
rwlock_t hash_lock;
mempool_t *region_pool;
unsigned int mask;
unsigned int nr_buckets;
struct list_head *buckets;
spinlock_t region_lock;
atomic_t recovery_in_flight;
struct semaphore recovery_count;
struct list_head clean_regions;
struct list_head quiesced_regions;
struct list_head recovered_regions;
struct list_head failed_recovered_regions;
};
enum {
RH_CLEAN,
RH_DIRTY,
RH_NOSYNC,
RH_RECOVERING
};
struct region {
struct region_hash *rh; /* FIXME: can we get rid of this ? */
region_t key;
int state;
struct list_head hash_list;
struct list_head list;
atomic_t pending;
struct bio_list delayed_bios;
};
/*-----------------------------------------------------------------
* Mirror set structures.
*---------------------------------------------------------------*/
......@@ -133,8 +51,7 @@ struct mirror {
struct mirror_set {
struct dm_target *ti;
struct list_head list;
struct region_hash rh;
struct dm_kcopyd_client *kcopyd_client;
uint64_t features;
spinlock_t lock; /* protects the lists */
......@@ -142,6 +59,8 @@ struct mirror_set {
struct bio_list writes;
struct bio_list failures;
struct dm_region_hash *rh;
struct dm_kcopyd_client *kcopyd_client;
struct dm_io_client *io_client;
mempool_t *read_record_pool;
......@@ -160,25 +79,14 @@ struct mirror_set {
struct work_struct trigger_event;
unsigned int nr_mirrors;
unsigned nr_mirrors;
struct mirror mirror[0];
};
/*
* Conversion fns
*/
static inline region_t bio_to_region(struct region_hash *rh, struct bio *bio)
static void wakeup_mirrord(void *context)
{
return (bio->bi_sector - rh->ms->ti->begin) >> rh->region_shift;
}
struct mirror_set *ms = context;
static inline sector_t region_to_sector(struct region_hash *rh, region_t region)
{
return region << rh->region_shift;
}
static void wake(struct mirror_set *ms)
{
queue_work(ms->kmirrord_wq, &ms->kmirrord_work);
}
......@@ -187,7 +95,7 @@ static void delayed_wake_fn(unsigned long data)
struct mirror_set *ms = (struct mirror_set *) data;
clear_bit(0, &ms->timer_pending);
wake(ms);
wakeup_mirrord(ms);
}
static void delayed_wake(struct mirror_set *ms)
......@@ -201,473 +109,34 @@ static void delayed_wake(struct mirror_set *ms)
add_timer(&ms->timer);
}
/* FIXME move this */
static void queue_bio(struct mirror_set *ms, struct bio *bio, int rw);
#define MIN_REGIONS 64
#define MAX_RECOVERY 1
static int rh_init(struct region_hash *rh, struct mirror_set *ms,
struct dm_dirty_log *log, uint32_t region_size,
region_t nr_regions)
{
unsigned int nr_buckets, max_buckets;
size_t i;
/*
* Calculate a suitable number of buckets for our hash
* table.
*/
max_buckets = nr_regions >> 6;
for (nr_buckets = 128u; nr_buckets < max_buckets; nr_buckets <<= 1)
;
nr_buckets >>= 1;
rh->ms = ms;
rh->log = log;
rh->region_size = region_size;
rh->region_shift = ffs(region_size) - 1;
rwlock_init(&rh->hash_lock);
rh->mask = nr_buckets - 1;
rh->nr_buckets = nr_buckets;
rh->buckets = vmalloc(nr_buckets * sizeof(*rh->buckets));
if (!rh->buckets) {
DMERR("unable to allocate region hash memory");
return -ENOMEM;
}
for (i = 0; i < nr_buckets; i++)
INIT_LIST_HEAD(rh->buckets + i);
spin_lock_init(&rh->region_lock);
sema_init(&rh->recovery_count, 0);
atomic_set(&rh->recovery_in_flight, 0);
INIT_LIST_HEAD(&rh->clean_regions);
INIT_LIST_HEAD(&rh->quiesced_regions);
INIT_LIST_HEAD(&rh->recovered_regions);
INIT_LIST_HEAD(&rh->failed_recovered_regions);
rh->region_pool = mempool_create_kmalloc_pool(MIN_REGIONS,
sizeof(struct region));
if (!rh->region_pool) {
vfree(rh->buckets);
rh->buckets = NULL;
return -ENOMEM;
}
return 0;
}
static void rh_exit(struct region_hash *rh)
{
unsigned int h;
struct region *reg, *nreg;
BUG_ON(!list_empty(&rh->quiesced_regions));
for (h = 0; h < rh->nr_buckets; h++) {
list_for_each_entry_safe(reg, nreg, rh->buckets + h, hash_list) {
BUG_ON(atomic_read(&reg->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)
static void wakeup_all_recovery_waiters(void *context)
{
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)
{
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, &reg->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(&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);
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(&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);
wakeup_mirrord(ms);
}
static int rh_flush(struct region_hash *rh)
static void dispatch_bios(void *context, struct bio_list *bio_list)
{
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(&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
......@@ -777,8 +246,8 @@ static void fail_mirror(struct mirror *m, enum dm_raid1_error error_type)
static void recovery_complete(int read_err, unsigned long write_err,
void *context)
{
struct region *reg = (struct region *)context;
struct mirror_set *ms = reg->rh->ms;
struct dm_region *reg = context;
struct mirror_set *ms = dm_rh_region_context(reg);
int m, bit = 0;
if (read_err) {
......@@ -804,31 +273,33 @@ static void recovery_complete(int read_err, unsigned long write_err,
}
}
rh_recovery_end(reg, !(read_err || write_err));
dm_rh_recovery_end(reg, !(read_err || write_err));
}
static int recover(struct mirror_set *ms, struct region *reg)
static int recover(struct mirror_set *ms, struct dm_region *reg)
{
int r;
unsigned int i;
unsigned i;
struct dm_io_region from, to[DM_KCOPYD_MAX_REGIONS], *dest;
struct mirror *m;
unsigned long flags = 0;
region_t key = dm_rh_get_region_key(reg);
sector_t region_size = dm_rh_get_region_size(ms->rh);
/* fill in the source */
m = get_default_mirror(ms);
from.bdev = m->dev->bdev;
from.sector = m->offset + region_to_sector(reg->rh, reg->key);
if (reg->key == (ms->nr_regions - 1)) {
from.sector = m->offset + dm_rh_region_to_sector(ms->rh, key);
if (key == (ms->nr_regions - 1)) {
/*
* The final region may be smaller than
* region_size.
*/
from.count = ms->ti->len & (reg->rh->region_size - 1);
from.count = ms->ti->len & (region_size - 1);
if (!from.count)
from.count = reg->rh->region_size;
from.count = region_size;
} else
from.count = reg->rh->region_size;
from.count = region_size;
/* fill in the destinations */
for (i = 0, dest = to; i < ms->nr_mirrors; i++) {
......@@ -837,7 +308,7 @@ static int recover(struct mirror_set *ms, struct region *reg)
m = ms->mirror + i;
dest->bdev = m->dev->bdev;
dest->sector = m->offset + region_to_sector(reg->rh, reg->key);
dest->sector = m->offset + dm_rh_region_to_sector(ms->rh, key);
dest->count = from.count;
dest++;
}
......@@ -854,22 +325,22 @@ static int recover(struct mirror_set *ms, struct region *reg)
static void do_recovery(struct mirror_set *ms)
{
struct dm_region *reg;
struct dm_dirty_log *log = dm_rh_dirty_log(ms->rh);
int r;
struct region *reg;
struct dm_dirty_log *log = ms->rh.log;
/*
* Start quiescing some regions.
*/
rh_recovery_prepare(&ms->rh);
dm_rh_recovery_prepare(ms->rh);
/*
* Copy any already quiesced regions.
*/
while ((reg = rh_recovery_start(&ms->rh))) {
while ((reg = dm_rh_recovery_start(ms->rh))) {
r = recover(ms, reg);
if (r)
rh_recovery_end(reg, 0);
dm_rh_recovery_end(reg, 0);
}
/*
......@@ -910,9 +381,10 @@ static int default_ok(struct mirror *m)
static int mirror_available(struct mirror_set *ms, struct bio *bio)
{
region_t region = bio_to_region(&ms->rh, bio);
struct dm_dirty_log *log = dm_rh_dirty_log(ms->rh);
region_t region = dm_rh_bio_to_region(ms->rh, bio);
if (ms->rh.log->type->in_sync(ms->rh.log, region, 0))
if (log->type->in_sync(log, region, 0))
return choose_mirror(ms, bio->bi_sector) ? 1 : 0;
return 0;
......@@ -986,7 +458,14 @@ static void read_async_bio(struct mirror *m, struct bio *bio)
map_region(&io, m, bio);
bio_set_m(bio, m);
(void) dm_io(&io_req, 1, &io, NULL);
BUG_ON(dm_io(&io_req, 1, &io, NULL));
}
static inline int region_in_sync(struct mirror_set *ms, region_t region,
int may_block)
{
int state = dm_rh_get_state(ms->rh, region, may_block);
return state == DM_RH_CLEAN || state == DM_RH_DIRTY;
}
static void do_reads(struct mirror_set *ms, struct bio_list *reads)
......@@ -996,13 +475,13 @@ static void do_reads(struct mirror_set *ms, struct bio_list *reads)
struct mirror *m;
while ((bio = bio_list_pop(reads))) {
region = bio_to_region(&ms->rh, bio);
region = dm_rh_bio_to_region(ms->rh, bio);
m = get_default_mirror(ms);
/*
* We can only read balance if the region is in sync.
*/
if (likely(rh_in_sync(&ms->rh, region, 1)))
if (likely(region_in_sync(ms, region, 1)))
m = choose_mirror(ms, bio->bi_sector);
else if (m && atomic_read(&m->error_count))
m = NULL;
......@@ -1025,57 +504,6 @@ static void do_reads(struct mirror_set *ms, struct bio_list *reads)
* NOSYNC: increment pending, just write to the default mirror
*---------------------------------------------------------------*/
/* __bio_mark_nosync
* @ms
* @bio
* @done
* @error
*
* The bio was written on some mirror(s) but failed on other mirror(s).
* We can successfully endio the bio but should avoid the region being
* marked clean by setting the state RH_NOSYNC.
*
* This function is _not_ safe in interrupt context!
*/
static void __bio_mark_nosync(struct mirror_set *ms,
struct bio *bio, unsigned done, int error)
{
unsigned long flags;
struct region_hash *rh = &ms->rh;
struct dm_dirty_log *log = ms->rh.log;
struct region *reg;
region_t region = bio_to_region(rh, bio);
int recovering = 0;
/* We must inform the log that the sync count has changed. */
log->type->set_region_sync(log, region, 0);
ms->in_sync = 0;
read_lock(&rh->hash_lock);
reg = __rh_find(rh, region);
read_unlock(&rh->hash_lock);
/* region hash entry should exist because write was in-flight */
BUG_ON(!reg);
BUG_ON(!list_empty(&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)
{
......@@ -1120,7 +548,7 @@ static void write_callback(unsigned long error, void *context)
bio_list_add(&ms->failures, bio);
spin_unlock_irqrestore(&ms->lock, flags);
if (should_wake)
wake(ms);
wakeup_mirrord(ms);
return;
}
out:
......@@ -1150,7 +578,7 @@ static void do_write(struct mirror_set *ms, struct bio *bio)
*/
bio_set_m(bio, get_default_mirror(ms));
(void) dm_io(&io_req, ms->nr_mirrors, io, NULL);
BUG_ON(dm_io(&io_req, ms->nr_mirrors, io, NULL));
}
static void do_writes(struct mirror_set *ms, struct bio_list *writes)
......@@ -1170,18 +598,19 @@ static void do_writes(struct mirror_set *ms, struct bio_list *writes)
bio_list_init(&recover);
while ((bio = bio_list_pop(writes))) {
state = rh_state(&ms->rh, bio_to_region(&ms->rh, bio), 1);
state = dm_rh_get_state(ms->rh,
dm_rh_bio_to_region(ms->rh, bio), 1);
switch (state) {
case RH_CLEAN:
case RH_DIRTY:
case DM_RH_CLEAN:
case DM_RH_DIRTY:
this_list = &sync;
break;
case RH_NOSYNC:
case DM_RH_NOSYNC:
this_list = &nosync;
break;
case RH_RECOVERING:
case DM_RH_RECOVERING:
this_list = &recover;
break;
}
......@@ -1194,9 +623,9 @@ static void do_writes(struct mirror_set *ms, struct bio_list *writes)
* be written to (writes to recover regions are going to
* be delayed).
*/
rh_inc_pending(&ms->rh, &sync);
rh_inc_pending(&ms->rh, &nosync);
ms->log_failure = rh_flush(&ms->rh) ? 1 : 0;
dm_rh_inc_pending(ms->rh, &sync);
dm_rh_inc_pending(ms->rh, &nosync);
ms->log_failure = dm_rh_flush(ms->rh) ? 1 : 0;
/*
* Dispatch io.
......@@ -1205,13 +634,13 @@ static void do_writes(struct mirror_set *ms, struct bio_list *writes)
spin_lock_irq(&ms->lock);
bio_list_merge(&ms->failures, &sync);
spin_unlock_irq(&ms->lock);
wake(ms);
wakeup_mirrord(ms);
} else
while ((bio = bio_list_pop(&sync)))
do_write(ms, bio);
while ((bio = bio_list_pop(&recover)))
rh_delay(&ms->rh, bio);
dm_rh_delay(ms->rh, bio);
while ((bio = bio_list_pop(&nosync))) {
map_bio(get_default_mirror(ms), bio);
......@@ -1228,7 +657,8 @@ static void do_failures(struct mirror_set *ms, struct bio_list *failures)
if (!ms->log_failure) {
while ((bio = bio_list_pop(failures)))
__bio_mark_nosync(ms, bio, bio->bi_size, 0);
ms->in_sync = 0;
dm_rh_mark_nosync(ms->rh, bio, bio->bi_size, 0);
return;
}
......@@ -1281,7 +711,7 @@ static void trigger_event(struct work_struct *work)
*---------------------------------------------------------------*/
static void do_mirror(struct work_struct *work)
{
struct mirror_set *ms =container_of(work, struct mirror_set,
struct mirror_set *ms = container_of(work, struct mirror_set,
kmirrord_work);
struct bio_list reads, writes, failures;
unsigned long flags;
......@@ -1295,7 +725,7 @@ static void do_mirror(struct work_struct *work)
bio_list_init(&ms->failures);
spin_unlock_irqrestore(&ms->lock, flags);
rh_update_states(&ms->rh);
dm_rh_update_states(ms->rh, errors_handled(ms));
do_recovery(ms);
do_reads(ms, &reads);
do_writes(ms, &writes);
......@@ -1304,7 +734,6 @@ static void do_mirror(struct work_struct *work)
dm_table_unplug_all(ms->ti->table);
}
/*-----------------------------------------------------------------
* Target functions
*---------------------------------------------------------------*/
......@@ -1351,7 +780,11 @@ static struct mirror_set *alloc_context(unsigned int nr_mirrors,
return NULL;
}
if (rh_init(&ms->rh, ms, dl, region_size, ms->nr_regions)) {
ms->rh = dm_region_hash_create(ms, dispatch_bios, wakeup_mirrord,
wakeup_all_recovery_waiters,
ms->ti->begin, MAX_RECOVERY,
dl, region_size, ms->nr_regions);
if (IS_ERR(ms->rh)) {
ti->error = "Error creating dirty region hash";
dm_io_client_destroy(ms->io_client);
mempool_destroy(ms->read_record_pool);
......@@ -1369,7 +802,7 @@ static void free_context(struct mirror_set *ms, struct dm_target *ti,
dm_put_device(ti, ms->mirror[m].dev);
dm_io_client_destroy(ms->io_client);
rh_exit(&ms->rh);
dm_region_hash_destroy(ms->rh);
mempool_destroy(ms->read_record_pool);
kfree(ms);
}
......@@ -1409,10 +842,10 @@ static int get_mirror(struct mirror_set *ms, struct dm_target *ti,
* Create dirty log: log_type #log_params <log_params>
*/
static struct dm_dirty_log *create_dirty_log(struct dm_target *ti,
unsigned int argc, char **argv,
unsigned int *args_used)
unsigned argc, char **argv,
unsigned *args_used)
{
unsigned int param_count;
unsigned param_count;
struct dm_dirty_log *dl;
if (argc < 2) {
......@@ -1543,7 +976,7 @@ static int mirror_ctr(struct dm_target *ti, unsigned int argc, char **argv)
}
ti->private = ms;
ti->split_io = ms->rh.region_size;
ti->split_io = dm_rh_get_region_size(ms->rh);
ms->kmirrord_wq = create_singlethread_workqueue("kmirrord");
if (!ms->kmirrord_wq) {
......@@ -1578,11 +1011,11 @@ static int mirror_ctr(struct dm_target *ti, unsigned int argc, char **argv)
goto err_destroy_wq;
}
r = dm_kcopyd_client_create(DM_IO_PAGES, &ms->kcopyd_client);
r = dm_kcopyd_client_create(DM_KCOPYD_PAGES, &ms->kcopyd_client);
if (r)
goto err_destroy_wq;
wake(ms);
wakeup_mirrord(ms);
return 0;
err_destroy_wq:
......@@ -1603,22 +1036,6 @@ static void mirror_dtr(struct dm_target *ti)
free_context(ms, ti, ms->nr_mirrors);
}
static void queue_bio(struct mirror_set *ms, struct bio *bio, int rw)
{
unsigned long flags;
int should_wake = 0;
struct bio_list *bl;
bl = (rw == WRITE) ? &ms->writes : &ms->reads;
spin_lock_irqsave(&ms->lock, flags);
should_wake = !(bl->head);
bio_list_add(bl, bio);
spin_unlock_irqrestore(&ms->lock, flags);
if (should_wake)
wake(ms);
}
/*
* Mirror mapping function
*/
......@@ -1629,16 +1046,16 @@ static int mirror_map(struct dm_target *ti, struct bio *bio,
struct mirror *m;
struct mirror_set *ms = ti->private;
struct dm_raid1_read_record *read_record = NULL;
struct dm_dirty_log *log = dm_rh_dirty_log(ms->rh);
if (rw == WRITE) {
/* Save region for mirror_end_io() handler */
map_context->ll = bio_to_region(&ms->rh, bio);
map_context->ll = dm_rh_bio_to_region(ms->rh, bio);
queue_bio(ms, bio, rw);
return DM_MAPIO_SUBMITTED;
}
r = ms->rh.log->type->in_sync(ms->rh.log,
bio_to_region(&ms->rh, bio), 0);
r = log->type->in_sync(log, dm_rh_bio_to_region(ms->rh, bio), 0);
if (r < 0 && r != -EWOULDBLOCK)
return r;
......@@ -1686,7 +1103,7 @@ static int mirror_end_io(struct dm_target *ti, struct bio *bio,
* We need to dec pending if this was a write.
*/
if (rw == WRITE) {
rh_dec(&ms->rh, map_context->ll);
dm_rh_dec(ms->rh, map_context->ll);
return error;
}
......@@ -1742,7 +1159,7 @@ static int mirror_end_io(struct dm_target *ti, struct bio *bio,
static void mirror_presuspend(struct dm_target *ti)
{
struct mirror_set *ms = (struct mirror_set *) ti->private;
struct dm_dirty_log *log = ms->rh.log;
struct dm_dirty_log *log = dm_rh_dirty_log(ms->rh);
atomic_set(&ms->suspend, 1);
......@@ -1750,10 +1167,10 @@ static void mirror_presuspend(struct dm_target *ti)
* We must finish up all the work that we've
* generated (i.e. recovery work).
*/
rh_stop_recovery(&ms->rh);
dm_rh_stop_recovery(ms->rh);
wait_event(_kmirrord_recovery_stopped,
!atomic_read(&ms->rh.recovery_in_flight));
!dm_rh_recovery_in_flight(ms->rh));
if (log->type->presuspend && log->type->presuspend(log))
/* FIXME: need better error handling */
......@@ -1771,7 +1188,7 @@ static void mirror_presuspend(struct dm_target *ti)
static void mirror_postsuspend(struct dm_target *ti)
{
struct mirror_set *ms = ti->private;
struct dm_dirty_log *log = ms->rh.log;
struct dm_dirty_log *log = dm_rh_dirty_log(ms->rh);
if (log->type->postsuspend && log->type->postsuspend(log))
/* FIXME: need better error handling */
......@@ -1781,13 +1198,13 @@ static void mirror_postsuspend(struct dm_target *ti)
static void mirror_resume(struct dm_target *ti)
{
struct mirror_set *ms = ti->private;
struct dm_dirty_log *log = ms->rh.log;
struct dm_dirty_log *log = dm_rh_dirty_log(ms->rh);
atomic_set(&ms->suspend, 0);
if (log->type->resume && log->type->resume(log))
/* FIXME: need better error handling */
DMWARN("log resume failed");
rh_start_recovery(&ms->rh);
dm_rh_start_recovery(ms->rh);
}
/*
......@@ -1819,7 +1236,7 @@ static int mirror_status(struct dm_target *ti, status_type_t type,
{
unsigned int m, sz = 0;
struct mirror_set *ms = (struct mirror_set *) ti->private;
struct dm_dirty_log *log = ms->rh.log;
struct dm_dirty_log *log = dm_rh_dirty_log(ms->rh);
char buffer[ms->nr_mirrors + 1];
switch (type) {
......@@ -1832,15 +1249,15 @@ static int mirror_status(struct dm_target *ti, status_type_t type,
buffer[m] = '\0';
DMEMIT("%llu/%llu 1 %s ",
(unsigned long long)log->type->get_sync_count(ms->rh.log),
(unsigned long long)log->type->get_sync_count(log),
(unsigned long long)ms->nr_regions, buffer);
sz += log->type->status(ms->rh.log, type, result+sz, maxlen-sz);
sz += log->type->status(log, type, result+sz, maxlen-sz);
break;
case STATUSTYPE_TABLE:
sz = log->type->status(ms->rh.log, type, result, maxlen);
sz = log->type->status(log, type, result, maxlen);
DMEMIT("%d", ms->nr_mirrors);
for (m = 0; m < ms->nr_mirrors; m++)
......
drivers/md/dm-region-hash.c 0 → 100644
View file @ 1f965b19
/*
* 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(&reg->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(&reg->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, &reg->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(&reg->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(&reg->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(&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 ? 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(&reg->pending);
if (reg->state == DM_RH_CLEAN) {
reg->state = DM_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);
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(&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 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(&reg->list, &rh->quiesced_regions);
} else if (reg->state == DM_RH_DIRTY) {
reg->state = DM_RH_CLEAN;
list_add(&reg->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, &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 = DM_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;
}
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(&reg->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(&reg->list, &reg->rh->recovered_regions);
else {
reg->state = DM_RH_NOSYNC;
list_add(&reg->list, &reg->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(&reg->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");
include/linux/dm-region-hash.h 0 → 100644
View file @ 1f965b19
/*
* Copyright (C) 2003 Sistina Software Limited.
* Copyright (C) 2004-2008 Red Hat, Inc. All rights reserved.
*
* Device-Mapper dirty region hash interface.
*
* This file is released under the GPL.
*/
#ifndef DM_REGION_HASH_H
#define DM_REGION_HASH_H
#include <linux/dm-dirty-log.h>
/*-----------------------------------------------------------------
* Region hash
*----------------------------------------------------------------*/
struct dm_region_hash;
struct dm_region;
/*
* States a region can have.
*/
enum dm_rh_region_states {
DM_RH_CLEAN = 0x01, /* No writes in flight. */
DM_RH_DIRTY = 0x02, /* Writes in flight. */
DM_RH_NOSYNC = 0x04, /* Out of sync. */
DM_RH_RECOVERING = 0x08, /* Under resynchronization. */
};
/*
* Region hash create/destroy.
*/
struct bio_list;
struct dm_region_hash *dm_region_hash_create(
void *context, void (*dispatch_bios)(void *context,
struct bio_list *bios),
void (*wakeup_workers)(void *context),
void (*wakeup_all_recovery_waiters)(void *context),
sector_t target_begin, unsigned max_recovery,
struct dm_dirty_log *log, uint32_t region_size,
region_t nr_regions);
void dm_region_hash_destroy(struct dm_region_hash *rh);
struct dm_dirty_log *dm_rh_dirty_log(struct dm_region_hash *rh);
/*
* Conversion functions.
*/
region_t dm_rh_bio_to_region(struct dm_region_hash *rh, struct bio *bio);
sector_t dm_rh_region_to_sector(struct dm_region_hash *rh, region_t region);
void *dm_rh_region_context(struct dm_region *reg);
/*
* Get region size and key (ie. number of the region).
*/
sector_t dm_rh_get_region_size(struct dm_region_hash *rh);
region_t dm_rh_get_region_key(struct dm_region *reg);
/*
* Get/set/update region state (and dirty log).
*
*/
int dm_rh_get_state(struct dm_region_hash *rh, region_t region, int may_block);
void dm_rh_set_state(struct dm_region_hash *rh, region_t region,
enum dm_rh_region_states state, int may_block);
/* Non-zero errors_handled leaves the state of the region NOSYNC */
void dm_rh_update_states(struct dm_region_hash *rh, int errors_handled);
/* Flush the region hash and dirty log. */
int dm_rh_flush(struct dm_region_hash *rh);
/* Inc/dec pending count on regions. */
void dm_rh_inc_pending(struct dm_region_hash *rh, struct bio_list *bios);
void dm_rh_dec(struct dm_region_hash *rh, region_t region);
/* Delay bios on regions. */
void dm_rh_delay(struct dm_region_hash *rh, struct bio *bio);
void dm_rh_mark_nosync(struct dm_region_hash *rh,
struct bio *bio, unsigned done, int error);
/*
* Region recovery control.
*/
/* Prepare some regions for recovery by starting to quiesce them. */
void dm_rh_recovery_prepare(struct dm_region_hash *rh);
/* Try fetching a quiesced region for recovery. */
struct dm_region *dm_rh_recovery_start(struct dm_region_hash *rh);
/* Report recovery end on a region. */
void dm_rh_recovery_end(struct dm_region *reg, int error);
/* Returns number of regions with recovery work outstanding. */
int dm_rh_recovery_in_flight(struct dm_region_hash *rh);
/* Start/stop recovery. */
void dm_rh_start_recovery(struct dm_region_hash *rh);
void dm_rh_stop_recovery(struct dm_region_hash *rh);
#endif /* DM_REGION_HASH_H */
Markdown is supported
0% or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment
GitLab Nexedi Edition | About GitLab | About Nexedi | 沪ICP备2021021310号-2 | 沪ICP备2021021310号-7