48f1f53282
This code was never designed to handle more than one instance of do_work() running at once. Signed-Off-By: Alasdair G Kergon <agk@redhat.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
1271 lines
28 KiB
C
1271 lines
28 KiB
C
/*
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* Copyright (C) 2003 Sistina Software Limited.
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*
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* This file is released under the GPL.
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*/
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#include "dm.h"
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#include "dm-bio-list.h"
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#include "dm-io.h"
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#include "dm-log.h"
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#include "kcopyd.h"
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#include <linux/ctype.h>
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#include <linux/init.h>
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#include <linux/mempool.h>
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#include <linux/module.h>
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#include <linux/pagemap.h>
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#include <linux/slab.h>
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#include <linux/time.h>
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#include <linux/vmalloc.h>
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#include <linux/workqueue.h>
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static struct workqueue_struct *_kmirrord_wq;
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static struct work_struct _kmirrord_work;
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static inline void wake(void)
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{
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queue_work(_kmirrord_wq, &_kmirrord_work);
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}
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/*-----------------------------------------------------------------
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* Region hash
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*
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* The mirror splits itself up into discrete regions. Each
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* region can be in one of three states: clean, dirty,
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* nosync. There is no need to put clean regions in the hash.
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*
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* In addition to being present in the hash table a region _may_
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* be present on one of three lists.
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*
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* clean_regions: Regions on this list have no io pending to
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* them, they are in sync, we are no longer interested in them,
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* they are dull. rh_update_states() will remove them from the
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* hash table.
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*
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* quiesced_regions: These regions have been spun down, ready
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* for recovery. rh_recovery_start() will remove regions from
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* this list and hand them to kmirrord, which will schedule the
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* recovery io with kcopyd.
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*
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* recovered_regions: Regions that kcopyd has successfully
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* recovered. rh_update_states() will now schedule any delayed
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* io, up the recovery_count, and remove the region from the
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* hash.
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*
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* There are 2 locks:
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* A rw spin lock 'hash_lock' protects just the hash table,
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* this is never held in write mode from interrupt context,
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* which I believe means that we only have to disable irqs when
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* doing a write lock.
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*
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* An ordinary spin lock 'region_lock' that protects the three
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* lists in the region_hash, with the 'state', 'list' and
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* 'bhs_delayed' fields of the regions. This is used from irq
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* context, so all other uses will have to suspend local irqs.
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*---------------------------------------------------------------*/
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struct mirror_set;
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struct region_hash {
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struct mirror_set *ms;
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uint32_t region_size;
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unsigned region_shift;
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/* holds persistent region state */
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struct dirty_log *log;
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/* hash table */
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rwlock_t hash_lock;
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mempool_t *region_pool;
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unsigned int mask;
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unsigned int nr_buckets;
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struct list_head *buckets;
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spinlock_t region_lock;
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struct semaphore recovery_count;
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struct list_head clean_regions;
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struct list_head quiesced_regions;
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struct list_head recovered_regions;
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};
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enum {
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RH_CLEAN,
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RH_DIRTY,
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RH_NOSYNC,
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RH_RECOVERING
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};
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struct region {
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struct region_hash *rh; /* FIXME: can we get rid of this ? */
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region_t key;
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int state;
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struct list_head hash_list;
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struct list_head list;
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atomic_t pending;
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struct bio_list delayed_bios;
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};
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/*
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* Conversion fns
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*/
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static inline region_t bio_to_region(struct region_hash *rh, struct bio *bio)
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{
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return bio->bi_sector >> rh->region_shift;
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}
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static inline sector_t region_to_sector(struct region_hash *rh, region_t region)
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{
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return region << rh->region_shift;
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}
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/* FIXME move this */
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static void queue_bio(struct mirror_set *ms, struct bio *bio, int rw);
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static void *region_alloc(unsigned int __nocast gfp_mask, void *pool_data)
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{
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return kmalloc(sizeof(struct region), gfp_mask);
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}
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static void region_free(void *element, void *pool_data)
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{
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kfree(element);
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}
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#define MIN_REGIONS 64
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#define MAX_RECOVERY 1
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static int rh_init(struct region_hash *rh, struct mirror_set *ms,
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struct dirty_log *log, uint32_t region_size,
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region_t nr_regions)
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{
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unsigned int nr_buckets, max_buckets;
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size_t i;
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/*
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* Calculate a suitable number of buckets for our hash
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* table.
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*/
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max_buckets = nr_regions >> 6;
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for (nr_buckets = 128u; nr_buckets < max_buckets; nr_buckets <<= 1)
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;
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nr_buckets >>= 1;
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rh->ms = ms;
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rh->log = log;
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rh->region_size = region_size;
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rh->region_shift = ffs(region_size) - 1;
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rwlock_init(&rh->hash_lock);
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rh->mask = nr_buckets - 1;
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rh->nr_buckets = nr_buckets;
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rh->buckets = vmalloc(nr_buckets * sizeof(*rh->buckets));
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if (!rh->buckets) {
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DMERR("unable to allocate region hash memory");
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return -ENOMEM;
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}
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for (i = 0; i < nr_buckets; i++)
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INIT_LIST_HEAD(rh->buckets + i);
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spin_lock_init(&rh->region_lock);
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sema_init(&rh->recovery_count, 0);
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INIT_LIST_HEAD(&rh->clean_regions);
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INIT_LIST_HEAD(&rh->quiesced_regions);
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INIT_LIST_HEAD(&rh->recovered_regions);
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rh->region_pool = mempool_create(MIN_REGIONS, region_alloc,
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region_free, NULL);
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if (!rh->region_pool) {
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vfree(rh->buckets);
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rh->buckets = NULL;
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return -ENOMEM;
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}
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return 0;
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}
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static void rh_exit(struct region_hash *rh)
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{
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unsigned int h;
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struct region *reg, *nreg;
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BUG_ON(!list_empty(&rh->quiesced_regions));
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for (h = 0; h < rh->nr_buckets; h++) {
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list_for_each_entry_safe(reg, nreg, rh->buckets + h, hash_list) {
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BUG_ON(atomic_read(®->pending));
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mempool_free(reg, rh->region_pool);
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}
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}
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if (rh->log)
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dm_destroy_dirty_log(rh->log);
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if (rh->region_pool)
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mempool_destroy(rh->region_pool);
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vfree(rh->buckets);
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}
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#define RH_HASH_MULT 2654435387U
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static inline unsigned int rh_hash(struct region_hash *rh, region_t region)
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{
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return (unsigned int) ((region * RH_HASH_MULT) >> 12) & rh->mask;
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}
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static struct region *__rh_lookup(struct region_hash *rh, region_t region)
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{
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struct region *reg;
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list_for_each_entry (reg, rh->buckets + rh_hash(rh, region), hash_list)
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if (reg->key == region)
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return reg;
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return NULL;
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}
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static void __rh_insert(struct region_hash *rh, struct region *reg)
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{
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unsigned int h = rh_hash(rh, reg->key);
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list_add(®->hash_list, rh->buckets + h);
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}
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static struct region *__rh_alloc(struct region_hash *rh, region_t region)
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{
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struct region *reg, *nreg;
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read_unlock(&rh->hash_lock);
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nreg = mempool_alloc(rh->region_pool, GFP_NOIO);
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nreg->state = rh->log->type->in_sync(rh->log, region, 1) ?
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RH_CLEAN : RH_NOSYNC;
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nreg->rh = rh;
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nreg->key = region;
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INIT_LIST_HEAD(&nreg->list);
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atomic_set(&nreg->pending, 0);
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bio_list_init(&nreg->delayed_bios);
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write_lock_irq(&rh->hash_lock);
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reg = __rh_lookup(rh, region);
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if (reg)
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/* we lost the race */
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mempool_free(nreg, rh->region_pool);
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else {
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__rh_insert(rh, nreg);
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if (nreg->state == RH_CLEAN) {
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spin_lock(&rh->region_lock);
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list_add(&nreg->list, &rh->clean_regions);
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spin_unlock(&rh->region_lock);
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}
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reg = nreg;
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}
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write_unlock_irq(&rh->hash_lock);
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read_lock(&rh->hash_lock);
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return reg;
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}
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static inline struct region *__rh_find(struct region_hash *rh, region_t region)
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{
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struct region *reg;
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reg = __rh_lookup(rh, region);
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if (!reg)
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reg = __rh_alloc(rh, region);
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return reg;
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}
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static int rh_state(struct region_hash *rh, region_t region, int may_block)
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{
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int r;
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struct region *reg;
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read_lock(&rh->hash_lock);
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reg = __rh_lookup(rh, region);
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read_unlock(&rh->hash_lock);
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if (reg)
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return reg->state;
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/*
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* The region wasn't in the hash, so we fall back to the
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* dirty log.
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*/
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r = rh->log->type->in_sync(rh->log, region, may_block);
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/*
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* Any error from the dirty log (eg. -EWOULDBLOCK) gets
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* taken as a RH_NOSYNC
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*/
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return r == 1 ? RH_CLEAN : RH_NOSYNC;
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}
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static inline int rh_in_sync(struct region_hash *rh,
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region_t region, int may_block)
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{
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int state = rh_state(rh, region, may_block);
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return state == RH_CLEAN || state == RH_DIRTY;
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}
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static void dispatch_bios(struct mirror_set *ms, struct bio_list *bio_list)
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{
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struct bio *bio;
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while ((bio = bio_list_pop(bio_list))) {
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queue_bio(ms, bio, WRITE);
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}
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}
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static void rh_update_states(struct region_hash *rh)
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{
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struct region *reg, *next;
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LIST_HEAD(clean);
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LIST_HEAD(recovered);
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/*
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* Quickly grab the lists.
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*/
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write_lock_irq(&rh->hash_lock);
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spin_lock(&rh->region_lock);
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if (!list_empty(&rh->clean_regions)) {
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list_splice(&rh->clean_regions, &clean);
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INIT_LIST_HEAD(&rh->clean_regions);
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list_for_each_entry (reg, &clean, list) {
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rh->log->type->clear_region(rh->log, reg->key);
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list_del(®->hash_list);
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}
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}
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if (!list_empty(&rh->recovered_regions)) {
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list_splice(&rh->recovered_regions, &recovered);
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INIT_LIST_HEAD(&rh->recovered_regions);
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list_for_each_entry (reg, &recovered, list)
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list_del(®->hash_list);
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}
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spin_unlock(&rh->region_lock);
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write_unlock_irq(&rh->hash_lock);
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/*
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* All the regions on the recovered and clean lists have
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* now been pulled out of the system, so no need to do
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* any more locking.
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*/
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list_for_each_entry_safe (reg, next, &recovered, list) {
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rh->log->type->clear_region(rh->log, reg->key);
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rh->log->type->complete_resync_work(rh->log, reg->key, 1);
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dispatch_bios(rh->ms, ®->delayed_bios);
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up(&rh->recovery_count);
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mempool_free(reg, rh->region_pool);
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}
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if (!list_empty(&recovered))
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rh->log->type->flush(rh->log);
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list_for_each_entry_safe (reg, next, &clean, list)
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mempool_free(reg, rh->region_pool);
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}
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static void rh_inc(struct region_hash *rh, region_t region)
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{
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struct region *reg;
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read_lock(&rh->hash_lock);
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reg = __rh_find(rh, region);
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if (reg->state == RH_CLEAN) {
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rh->log->type->mark_region(rh->log, reg->key);
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spin_lock_irq(&rh->region_lock);
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reg->state = RH_DIRTY;
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list_del_init(®->list); /* take off the clean list */
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spin_unlock_irq(&rh->region_lock);
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}
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atomic_inc(®->pending);
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read_unlock(&rh->hash_lock);
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}
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static void rh_inc_pending(struct region_hash *rh, struct bio_list *bios)
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{
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struct bio *bio;
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for (bio = bios->head; bio; bio = bio->bi_next)
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rh_inc(rh, bio_to_region(rh, bio));
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}
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static void rh_dec(struct region_hash *rh, region_t region)
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{
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unsigned long flags;
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struct region *reg;
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int should_wake = 0;
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read_lock(&rh->hash_lock);
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reg = __rh_lookup(rh, region);
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read_unlock(&rh->hash_lock);
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if (atomic_dec_and_test(®->pending)) {
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spin_lock_irqsave(&rh->region_lock, flags);
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if (reg->state == RH_RECOVERING) {
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list_add_tail(®->list, &rh->quiesced_regions);
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} else {
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reg->state = RH_CLEAN;
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list_add(®->list, &rh->clean_regions);
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}
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spin_unlock_irqrestore(&rh->region_lock, flags);
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should_wake = 1;
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}
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if (should_wake)
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wake();
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}
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/*
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* Starts quiescing a region in preparation for recovery.
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*/
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static int __rh_recovery_prepare(struct region_hash *rh)
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{
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int r;
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struct region *reg;
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region_t region;
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/*
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* Ask the dirty log what's next.
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*/
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r = rh->log->type->get_resync_work(rh->log, ®ion);
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if (r <= 0)
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return r;
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/*
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* Get this region, and start it quiescing by setting the
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* recovering flag.
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*/
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read_lock(&rh->hash_lock);
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reg = __rh_find(rh, region);
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read_unlock(&rh->hash_lock);
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spin_lock_irq(&rh->region_lock);
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reg->state = RH_RECOVERING;
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/* Already quiesced ? */
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if (atomic_read(®->pending))
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list_del_init(®->list);
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else {
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list_del_init(®->list);
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list_add(®->list, &rh->quiesced_regions);
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}
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spin_unlock_irq(&rh->region_lock);
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return 1;
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}
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static void rh_recovery_prepare(struct region_hash *rh)
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{
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while (!down_trylock(&rh->recovery_count))
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if (__rh_recovery_prepare(rh) <= 0) {
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up(&rh->recovery_count);
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break;
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}
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}
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/*
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* Returns any quiesced regions.
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*/
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static struct region *rh_recovery_start(struct region_hash *rh)
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{
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struct region *reg = NULL;
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spin_lock_irq(&rh->region_lock);
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if (!list_empty(&rh->quiesced_regions)) {
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reg = list_entry(rh->quiesced_regions.next,
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struct region, list);
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list_del_init(®->list); /* remove from the quiesced list */
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}
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spin_unlock_irq(&rh->region_lock);
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return reg;
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}
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/* FIXME: success ignored for now */
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static void rh_recovery_end(struct region *reg, int success)
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{
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struct region_hash *rh = reg->rh;
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spin_lock_irq(&rh->region_lock);
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list_add(®->list, ®->rh->recovered_regions);
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spin_unlock_irq(&rh->region_lock);
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wake();
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}
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static void rh_flush(struct region_hash *rh)
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{
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rh->log->type->flush(rh->log);
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}
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static void rh_delay(struct region_hash *rh, struct bio *bio)
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{
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struct region *reg;
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read_lock(&rh->hash_lock);
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reg = __rh_find(rh, bio_to_region(rh, bio));
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bio_list_add(®->delayed_bios, bio);
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read_unlock(&rh->hash_lock);
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}
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static void rh_stop_recovery(struct region_hash *rh)
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{
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int i;
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/* wait for any recovering regions */
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for (i = 0; i < MAX_RECOVERY; i++)
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down(&rh->recovery_count);
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}
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static void rh_start_recovery(struct region_hash *rh)
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{
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int i;
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for (i = 0; i < MAX_RECOVERY; i++)
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up(&rh->recovery_count);
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wake();
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}
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|
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/*-----------------------------------------------------------------
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* Mirror set structures.
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*---------------------------------------------------------------*/
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struct mirror {
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atomic_t error_count;
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struct dm_dev *dev;
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sector_t offset;
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};
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|
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struct mirror_set {
|
|
struct dm_target *ti;
|
|
struct list_head list;
|
|
struct region_hash rh;
|
|
struct kcopyd_client *kcopyd_client;
|
|
|
|
spinlock_t lock; /* protects the next two lists */
|
|
struct bio_list reads;
|
|
struct bio_list writes;
|
|
|
|
/* recovery */
|
|
region_t nr_regions;
|
|
int in_sync;
|
|
|
|
unsigned int nr_mirrors;
|
|
struct mirror mirror[0];
|
|
};
|
|
|
|
/*
|
|
* Every mirror should look like this one.
|
|
*/
|
|
#define DEFAULT_MIRROR 0
|
|
|
|
/*
|
|
* This is yucky. We squirrel the mirror_set struct away inside
|
|
* bi_next for write buffers. This is safe since the bh
|
|
* doesn't get submitted to the lower levels of block layer.
|
|
*/
|
|
static struct mirror_set *bio_get_ms(struct bio *bio)
|
|
{
|
|
return (struct mirror_set *) bio->bi_next;
|
|
}
|
|
|
|
static void bio_set_ms(struct bio *bio, struct mirror_set *ms)
|
|
{
|
|
bio->bi_next = (struct bio *) ms;
|
|
}
|
|
|
|
/*-----------------------------------------------------------------
|
|
* Recovery.
|
|
*
|
|
* When a mirror is first activated we may find that some regions
|
|
* are in the no-sync state. We have to recover these by
|
|
* recopying from the default mirror to all the others.
|
|
*---------------------------------------------------------------*/
|
|
static void recovery_complete(int read_err, unsigned int write_err,
|
|
void *context)
|
|
{
|
|
struct region *reg = (struct region *) context;
|
|
|
|
/* FIXME: better error handling */
|
|
rh_recovery_end(reg, read_err || write_err);
|
|
}
|
|
|
|
static int recover(struct mirror_set *ms, struct region *reg)
|
|
{
|
|
int r;
|
|
unsigned int i;
|
|
struct io_region from, to[KCOPYD_MAX_REGIONS], *dest;
|
|
struct mirror *m;
|
|
unsigned long flags = 0;
|
|
|
|
/* fill in the source */
|
|
m = ms->mirror + DEFAULT_MIRROR;
|
|
from.bdev = m->dev->bdev;
|
|
from.sector = m->offset + region_to_sector(reg->rh, reg->key);
|
|
if (reg->key == (ms->nr_regions - 1)) {
|
|
/*
|
|
* The final region may be smaller than
|
|
* region_size.
|
|
*/
|
|
from.count = ms->ti->len & (reg->rh->region_size - 1);
|
|
if (!from.count)
|
|
from.count = reg->rh->region_size;
|
|
} else
|
|
from.count = reg->rh->region_size;
|
|
|
|
/* fill in the destinations */
|
|
for (i = 0, dest = to; i < ms->nr_mirrors; i++) {
|
|
if (i == DEFAULT_MIRROR)
|
|
continue;
|
|
|
|
m = ms->mirror + i;
|
|
dest->bdev = m->dev->bdev;
|
|
dest->sector = m->offset + region_to_sector(reg->rh, reg->key);
|
|
dest->count = from.count;
|
|
dest++;
|
|
}
|
|
|
|
/* hand to kcopyd */
|
|
set_bit(KCOPYD_IGNORE_ERROR, &flags);
|
|
r = kcopyd_copy(ms->kcopyd_client, &from, ms->nr_mirrors - 1, to, flags,
|
|
recovery_complete, reg);
|
|
|
|
return r;
|
|
}
|
|
|
|
static void do_recovery(struct mirror_set *ms)
|
|
{
|
|
int r;
|
|
struct region *reg;
|
|
struct dirty_log *log = ms->rh.log;
|
|
|
|
/*
|
|
* Start quiescing some regions.
|
|
*/
|
|
rh_recovery_prepare(&ms->rh);
|
|
|
|
/*
|
|
* Copy any already quiesced regions.
|
|
*/
|
|
while ((reg = rh_recovery_start(&ms->rh))) {
|
|
r = recover(ms, reg);
|
|
if (r)
|
|
rh_recovery_end(reg, 0);
|
|
}
|
|
|
|
/*
|
|
* Update the in sync flag.
|
|
*/
|
|
if (!ms->in_sync &&
|
|
(log->type->get_sync_count(log) == ms->nr_regions)) {
|
|
/* the sync is complete */
|
|
dm_table_event(ms->ti->table);
|
|
ms->in_sync = 1;
|
|
}
|
|
}
|
|
|
|
/*-----------------------------------------------------------------
|
|
* Reads
|
|
*---------------------------------------------------------------*/
|
|
static struct mirror *choose_mirror(struct mirror_set *ms, sector_t sector)
|
|
{
|
|
/* FIXME: add read balancing */
|
|
return ms->mirror + DEFAULT_MIRROR;
|
|
}
|
|
|
|
/*
|
|
* remap a buffer to a particular mirror.
|
|
*/
|
|
static void map_bio(struct mirror_set *ms, struct mirror *m, struct bio *bio)
|
|
{
|
|
bio->bi_bdev = m->dev->bdev;
|
|
bio->bi_sector = m->offset + (bio->bi_sector - ms->ti->begin);
|
|
}
|
|
|
|
static void do_reads(struct mirror_set *ms, struct bio_list *reads)
|
|
{
|
|
region_t region;
|
|
struct bio *bio;
|
|
struct mirror *m;
|
|
|
|
while ((bio = bio_list_pop(reads))) {
|
|
region = bio_to_region(&ms->rh, bio);
|
|
|
|
/*
|
|
* We can only read balance if the region is in sync.
|
|
*/
|
|
if (rh_in_sync(&ms->rh, region, 0))
|
|
m = choose_mirror(ms, bio->bi_sector);
|
|
else
|
|
m = ms->mirror + DEFAULT_MIRROR;
|
|
|
|
map_bio(ms, m, bio);
|
|
generic_make_request(bio);
|
|
}
|
|
}
|
|
|
|
/*-----------------------------------------------------------------
|
|
* Writes.
|
|
*
|
|
* We do different things with the write io depending on the
|
|
* state of the region that it's in:
|
|
*
|
|
* SYNC: increment pending, use kcopyd to write to *all* mirrors
|
|
* RECOVERING: delay the io until recovery completes
|
|
* NOSYNC: increment pending, just write to the default mirror
|
|
*---------------------------------------------------------------*/
|
|
static void write_callback(unsigned long error, void *context)
|
|
{
|
|
unsigned int i;
|
|
int uptodate = 1;
|
|
struct bio *bio = (struct bio *) context;
|
|
struct mirror_set *ms;
|
|
|
|
ms = bio_get_ms(bio);
|
|
bio_set_ms(bio, NULL);
|
|
|
|
/*
|
|
* NOTE: We don't decrement the pending count here,
|
|
* instead it is done by the targets endio function.
|
|
* This way we handle both writes to SYNC and NOSYNC
|
|
* regions with the same code.
|
|
*/
|
|
|
|
if (error) {
|
|
/*
|
|
* only error the io if all mirrors failed.
|
|
* FIXME: bogus
|
|
*/
|
|
uptodate = 0;
|
|
for (i = 0; i < ms->nr_mirrors; i++)
|
|
if (!test_bit(i, &error)) {
|
|
uptodate = 1;
|
|
break;
|
|
}
|
|
}
|
|
bio_endio(bio, bio->bi_size, 0);
|
|
}
|
|
|
|
static void do_write(struct mirror_set *ms, struct bio *bio)
|
|
{
|
|
unsigned int i;
|
|
struct io_region io[KCOPYD_MAX_REGIONS+1];
|
|
struct mirror *m;
|
|
|
|
for (i = 0; i < ms->nr_mirrors; i++) {
|
|
m = ms->mirror + i;
|
|
|
|
io[i].bdev = m->dev->bdev;
|
|
io[i].sector = m->offset + (bio->bi_sector - ms->ti->begin);
|
|
io[i].count = bio->bi_size >> 9;
|
|
}
|
|
|
|
bio_set_ms(bio, ms);
|
|
dm_io_async_bvec(ms->nr_mirrors, io, WRITE,
|
|
bio->bi_io_vec + bio->bi_idx,
|
|
write_callback, bio);
|
|
}
|
|
|
|
static void do_writes(struct mirror_set *ms, struct bio_list *writes)
|
|
{
|
|
int state;
|
|
struct bio *bio;
|
|
struct bio_list sync, nosync, recover, *this_list = NULL;
|
|
|
|
if (!writes->head)
|
|
return;
|
|
|
|
/*
|
|
* Classify each write.
|
|
*/
|
|
bio_list_init(&sync);
|
|
bio_list_init(&nosync);
|
|
bio_list_init(&recover);
|
|
|
|
while ((bio = bio_list_pop(writes))) {
|
|
state = rh_state(&ms->rh, bio_to_region(&ms->rh, bio), 1);
|
|
switch (state) {
|
|
case RH_CLEAN:
|
|
case RH_DIRTY:
|
|
this_list = &sync;
|
|
break;
|
|
|
|
case RH_NOSYNC:
|
|
this_list = &nosync;
|
|
break;
|
|
|
|
case RH_RECOVERING:
|
|
this_list = &recover;
|
|
break;
|
|
}
|
|
|
|
bio_list_add(this_list, bio);
|
|
}
|
|
|
|
/*
|
|
* Increment the pending counts for any regions that will
|
|
* be written to (writes to recover regions are going to
|
|
* be delayed).
|
|
*/
|
|
rh_inc_pending(&ms->rh, &sync);
|
|
rh_inc_pending(&ms->rh, &nosync);
|
|
rh_flush(&ms->rh);
|
|
|
|
/*
|
|
* Dispatch io.
|
|
*/
|
|
while ((bio = bio_list_pop(&sync)))
|
|
do_write(ms, bio);
|
|
|
|
while ((bio = bio_list_pop(&recover)))
|
|
rh_delay(&ms->rh, bio);
|
|
|
|
while ((bio = bio_list_pop(&nosync))) {
|
|
map_bio(ms, ms->mirror + DEFAULT_MIRROR, bio);
|
|
generic_make_request(bio);
|
|
}
|
|
}
|
|
|
|
/*-----------------------------------------------------------------
|
|
* kmirrord
|
|
*---------------------------------------------------------------*/
|
|
static LIST_HEAD(_mirror_sets);
|
|
static DECLARE_RWSEM(_mirror_sets_lock);
|
|
|
|
static void do_mirror(struct mirror_set *ms)
|
|
{
|
|
struct bio_list reads, writes;
|
|
|
|
spin_lock(&ms->lock);
|
|
reads = ms->reads;
|
|
writes = ms->writes;
|
|
bio_list_init(&ms->reads);
|
|
bio_list_init(&ms->writes);
|
|
spin_unlock(&ms->lock);
|
|
|
|
rh_update_states(&ms->rh);
|
|
do_recovery(ms);
|
|
do_reads(ms, &reads);
|
|
do_writes(ms, &writes);
|
|
}
|
|
|
|
static void do_work(void *ignored)
|
|
{
|
|
struct mirror_set *ms;
|
|
|
|
down_read(&_mirror_sets_lock);
|
|
list_for_each_entry (ms, &_mirror_sets, list)
|
|
do_mirror(ms);
|
|
up_read(&_mirror_sets_lock);
|
|
}
|
|
|
|
/*-----------------------------------------------------------------
|
|
* Target functions
|
|
*---------------------------------------------------------------*/
|
|
static struct mirror_set *alloc_context(unsigned int nr_mirrors,
|
|
uint32_t region_size,
|
|
struct dm_target *ti,
|
|
struct dirty_log *dl)
|
|
{
|
|
size_t len;
|
|
struct mirror_set *ms = NULL;
|
|
|
|
if (array_too_big(sizeof(*ms), sizeof(ms->mirror[0]), nr_mirrors))
|
|
return NULL;
|
|
|
|
len = sizeof(*ms) + (sizeof(ms->mirror[0]) * nr_mirrors);
|
|
|
|
ms = kmalloc(len, GFP_KERNEL);
|
|
if (!ms) {
|
|
ti->error = "dm-mirror: Cannot allocate mirror context";
|
|
return NULL;
|
|
}
|
|
|
|
memset(ms, 0, len);
|
|
spin_lock_init(&ms->lock);
|
|
|
|
ms->ti = ti;
|
|
ms->nr_mirrors = nr_mirrors;
|
|
ms->nr_regions = dm_sector_div_up(ti->len, region_size);
|
|
ms->in_sync = 0;
|
|
|
|
if (rh_init(&ms->rh, ms, dl, region_size, ms->nr_regions)) {
|
|
ti->error = "dm-mirror: Error creating dirty region hash";
|
|
kfree(ms);
|
|
return NULL;
|
|
}
|
|
|
|
return ms;
|
|
}
|
|
|
|
static void free_context(struct mirror_set *ms, struct dm_target *ti,
|
|
unsigned int m)
|
|
{
|
|
while (m--)
|
|
dm_put_device(ti, ms->mirror[m].dev);
|
|
|
|
rh_exit(&ms->rh);
|
|
kfree(ms);
|
|
}
|
|
|
|
static inline int _check_region_size(struct dm_target *ti, uint32_t size)
|
|
{
|
|
return !(size % (PAGE_SIZE >> 9) || (size & (size - 1)) ||
|
|
size > ti->len);
|
|
}
|
|
|
|
static int get_mirror(struct mirror_set *ms, struct dm_target *ti,
|
|
unsigned int mirror, char **argv)
|
|
{
|
|
sector_t offset;
|
|
|
|
if (sscanf(argv[1], SECTOR_FORMAT, &offset) != 1) {
|
|
ti->error = "dm-mirror: Invalid offset";
|
|
return -EINVAL;
|
|
}
|
|
|
|
if (dm_get_device(ti, argv[0], offset, ti->len,
|
|
dm_table_get_mode(ti->table),
|
|
&ms->mirror[mirror].dev)) {
|
|
ti->error = "dm-mirror: Device lookup failure";
|
|
return -ENXIO;
|
|
}
|
|
|
|
ms->mirror[mirror].offset = offset;
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int add_mirror_set(struct mirror_set *ms)
|
|
{
|
|
down_write(&_mirror_sets_lock);
|
|
list_add_tail(&ms->list, &_mirror_sets);
|
|
up_write(&_mirror_sets_lock);
|
|
wake();
|
|
|
|
return 0;
|
|
}
|
|
|
|
static void del_mirror_set(struct mirror_set *ms)
|
|
{
|
|
down_write(&_mirror_sets_lock);
|
|
list_del(&ms->list);
|
|
up_write(&_mirror_sets_lock);
|
|
}
|
|
|
|
/*
|
|
* Create dirty log: log_type #log_params <log_params>
|
|
*/
|
|
static struct dirty_log *create_dirty_log(struct dm_target *ti,
|
|
unsigned int argc, char **argv,
|
|
unsigned int *args_used)
|
|
{
|
|
unsigned int param_count;
|
|
struct dirty_log *dl;
|
|
|
|
if (argc < 2) {
|
|
ti->error = "dm-mirror: Insufficient mirror log arguments";
|
|
return NULL;
|
|
}
|
|
|
|
if (sscanf(argv[1], "%u", ¶m_count) != 1) {
|
|
ti->error = "dm-mirror: Invalid mirror log argument count";
|
|
return NULL;
|
|
}
|
|
|
|
*args_used = 2 + param_count;
|
|
|
|
if (argc < *args_used) {
|
|
ti->error = "dm-mirror: Insufficient mirror log arguments";
|
|
return NULL;
|
|
}
|
|
|
|
dl = dm_create_dirty_log(argv[0], ti, param_count, argv + 2);
|
|
if (!dl) {
|
|
ti->error = "dm-mirror: Error creating mirror dirty log";
|
|
return NULL;
|
|
}
|
|
|
|
if (!_check_region_size(ti, dl->type->get_region_size(dl))) {
|
|
ti->error = "dm-mirror: Invalid region size";
|
|
dm_destroy_dirty_log(dl);
|
|
return NULL;
|
|
}
|
|
|
|
return dl;
|
|
}
|
|
|
|
/*
|
|
* Construct a mirror mapping:
|
|
*
|
|
* log_type #log_params <log_params>
|
|
* #mirrors [mirror_path offset]{2,}
|
|
*
|
|
* log_type is "core" or "disk"
|
|
* #log_params is between 1 and 3
|
|
*/
|
|
#define DM_IO_PAGES 64
|
|
static int mirror_ctr(struct dm_target *ti, unsigned int argc, char **argv)
|
|
{
|
|
int r;
|
|
unsigned int nr_mirrors, m, args_used;
|
|
struct mirror_set *ms;
|
|
struct dirty_log *dl;
|
|
|
|
dl = create_dirty_log(ti, argc, argv, &args_used);
|
|
if (!dl)
|
|
return -EINVAL;
|
|
|
|
argv += args_used;
|
|
argc -= args_used;
|
|
|
|
if (!argc || sscanf(argv[0], "%u", &nr_mirrors) != 1 ||
|
|
nr_mirrors < 2 || nr_mirrors > KCOPYD_MAX_REGIONS + 1) {
|
|
ti->error = "dm-mirror: Invalid number of mirrors";
|
|
dm_destroy_dirty_log(dl);
|
|
return -EINVAL;
|
|
}
|
|
|
|
argv++, argc--;
|
|
|
|
if (argc != nr_mirrors * 2) {
|
|
ti->error = "dm-mirror: Wrong number of mirror arguments";
|
|
dm_destroy_dirty_log(dl);
|
|
return -EINVAL;
|
|
}
|
|
|
|
ms = alloc_context(nr_mirrors, dl->type->get_region_size(dl), ti, dl);
|
|
if (!ms) {
|
|
dm_destroy_dirty_log(dl);
|
|
return -ENOMEM;
|
|
}
|
|
|
|
/* Get the mirror parameter sets */
|
|
for (m = 0; m < nr_mirrors; m++) {
|
|
r = get_mirror(ms, ti, m, argv);
|
|
if (r) {
|
|
free_context(ms, ti, m);
|
|
return r;
|
|
}
|
|
argv += 2;
|
|
argc -= 2;
|
|
}
|
|
|
|
ti->private = ms;
|
|
ti->split_io = ms->rh.region_size;
|
|
|
|
r = kcopyd_client_create(DM_IO_PAGES, &ms->kcopyd_client);
|
|
if (r) {
|
|
free_context(ms, ti, ms->nr_mirrors);
|
|
return r;
|
|
}
|
|
|
|
add_mirror_set(ms);
|
|
return 0;
|
|
}
|
|
|
|
static void mirror_dtr(struct dm_target *ti)
|
|
{
|
|
struct mirror_set *ms = (struct mirror_set *) ti->private;
|
|
|
|
del_mirror_set(ms);
|
|
kcopyd_client_destroy(ms->kcopyd_client);
|
|
free_context(ms, ti, ms->nr_mirrors);
|
|
}
|
|
|
|
static void queue_bio(struct mirror_set *ms, struct bio *bio, int rw)
|
|
{
|
|
int should_wake = 0;
|
|
struct bio_list *bl;
|
|
|
|
bl = (rw == WRITE) ? &ms->writes : &ms->reads;
|
|
spin_lock(&ms->lock);
|
|
should_wake = !(bl->head);
|
|
bio_list_add(bl, bio);
|
|
spin_unlock(&ms->lock);
|
|
|
|
if (should_wake)
|
|
wake();
|
|
}
|
|
|
|
/*
|
|
* Mirror mapping function
|
|
*/
|
|
static int mirror_map(struct dm_target *ti, struct bio *bio,
|
|
union map_info *map_context)
|
|
{
|
|
int r, rw = bio_rw(bio);
|
|
struct mirror *m;
|
|
struct mirror_set *ms = ti->private;
|
|
|
|
map_context->ll = bio->bi_sector >> ms->rh.region_shift;
|
|
|
|
if (rw == WRITE) {
|
|
queue_bio(ms, bio, rw);
|
|
return 0;
|
|
}
|
|
|
|
r = ms->rh.log->type->in_sync(ms->rh.log,
|
|
bio_to_region(&ms->rh, bio), 0);
|
|
if (r < 0 && r != -EWOULDBLOCK)
|
|
return r;
|
|
|
|
if (r == -EWOULDBLOCK) /* FIXME: ugly */
|
|
r = 0;
|
|
|
|
/*
|
|
* We don't want to fast track a recovery just for a read
|
|
* ahead. So we just let it silently fail.
|
|
* FIXME: get rid of this.
|
|
*/
|
|
if (!r && rw == READA)
|
|
return -EIO;
|
|
|
|
if (!r) {
|
|
/* Pass this io over to the daemon */
|
|
queue_bio(ms, bio, rw);
|
|
return 0;
|
|
}
|
|
|
|
m = choose_mirror(ms, bio->bi_sector);
|
|
if (!m)
|
|
return -EIO;
|
|
|
|
map_bio(ms, m, bio);
|
|
return 1;
|
|
}
|
|
|
|
static int mirror_end_io(struct dm_target *ti, struct bio *bio,
|
|
int error, union map_info *map_context)
|
|
{
|
|
int rw = bio_rw(bio);
|
|
struct mirror_set *ms = (struct mirror_set *) ti->private;
|
|
region_t region = map_context->ll;
|
|
|
|
/*
|
|
* We need to dec pending if this was a write.
|
|
*/
|
|
if (rw == WRITE)
|
|
rh_dec(&ms->rh, region);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static void mirror_postsuspend(struct dm_target *ti)
|
|
{
|
|
struct mirror_set *ms = (struct mirror_set *) ti->private;
|
|
struct dirty_log *log = ms->rh.log;
|
|
|
|
rh_stop_recovery(&ms->rh);
|
|
if (log->type->suspend && log->type->suspend(log))
|
|
/* FIXME: need better error handling */
|
|
DMWARN("log suspend failed");
|
|
}
|
|
|
|
static void mirror_resume(struct dm_target *ti)
|
|
{
|
|
struct mirror_set *ms = (struct mirror_set *) ti->private;
|
|
struct dirty_log *log = ms->rh.log;
|
|
if (log->type->resume && log->type->resume(log))
|
|
/* FIXME: need better error handling */
|
|
DMWARN("log resume failed");
|
|
rh_start_recovery(&ms->rh);
|
|
}
|
|
|
|
static int mirror_status(struct dm_target *ti, status_type_t type,
|
|
char *result, unsigned int maxlen)
|
|
{
|
|
unsigned int m, sz;
|
|
struct mirror_set *ms = (struct mirror_set *) ti->private;
|
|
|
|
sz = ms->rh.log->type->status(ms->rh.log, type, result, maxlen);
|
|
|
|
switch (type) {
|
|
case STATUSTYPE_INFO:
|
|
DMEMIT("%d ", ms->nr_mirrors);
|
|
for (m = 0; m < ms->nr_mirrors; m++)
|
|
DMEMIT("%s ", ms->mirror[m].dev->name);
|
|
|
|
DMEMIT(SECTOR_FORMAT "/" SECTOR_FORMAT,
|
|
ms->rh.log->type->get_sync_count(ms->rh.log),
|
|
ms->nr_regions);
|
|
break;
|
|
|
|
case STATUSTYPE_TABLE:
|
|
DMEMIT("%d ", ms->nr_mirrors);
|
|
for (m = 0; m < ms->nr_mirrors; m++)
|
|
DMEMIT("%s " SECTOR_FORMAT " ",
|
|
ms->mirror[m].dev->name, ms->mirror[m].offset);
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
static struct target_type mirror_target = {
|
|
.name = "mirror",
|
|
.version = {1, 0, 1},
|
|
.module = THIS_MODULE,
|
|
.ctr = mirror_ctr,
|
|
.dtr = mirror_dtr,
|
|
.map = mirror_map,
|
|
.end_io = mirror_end_io,
|
|
.postsuspend = mirror_postsuspend,
|
|
.resume = mirror_resume,
|
|
.status = mirror_status,
|
|
};
|
|
|
|
static int __init dm_mirror_init(void)
|
|
{
|
|
int r;
|
|
|
|
r = dm_dirty_log_init();
|
|
if (r)
|
|
return r;
|
|
|
|
_kmirrord_wq = create_singlethread_workqueue("kmirrord");
|
|
if (!_kmirrord_wq) {
|
|
DMERR("couldn't start kmirrord");
|
|
dm_dirty_log_exit();
|
|
return r;
|
|
}
|
|
INIT_WORK(&_kmirrord_work, do_work, NULL);
|
|
|
|
r = dm_register_target(&mirror_target);
|
|
if (r < 0) {
|
|
DMERR("%s: Failed to register mirror target",
|
|
mirror_target.name);
|
|
dm_dirty_log_exit();
|
|
destroy_workqueue(_kmirrord_wq);
|
|
}
|
|
|
|
return r;
|
|
}
|
|
|
|
static void __exit dm_mirror_exit(void)
|
|
{
|
|
int r;
|
|
|
|
r = dm_unregister_target(&mirror_target);
|
|
if (r < 0)
|
|
DMERR("%s: unregister failed %d", mirror_target.name, r);
|
|
|
|
destroy_workqueue(_kmirrord_wq);
|
|
dm_dirty_log_exit();
|
|
}
|
|
|
|
/* Module hooks */
|
|
module_init(dm_mirror_init);
|
|
module_exit(dm_mirror_exit);
|
|
|
|
MODULE_DESCRIPTION(DM_NAME " mirror target");
|
|
MODULE_AUTHOR("Joe Thornber");
|
|
MODULE_LICENSE("GPL");
|