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Fixes generated by 'codespell' and manually reviewed. Signed-off-by: Lucas De Marchi <lucas.demarchi@profusion.mobi>
721 lines
18 KiB
C
721 lines
18 KiB
C
/*
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* Copyright (C) 2003 Sistina Software Limited.
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* Copyright (C) 2004-2008 Red Hat, Inc. All rights reserved.
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*
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* This file is released under the GPL.
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*/
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#include <linux/dm-dirty-log.h>
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#include <linux/dm-region-hash.h>
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#include <linux/ctype.h>
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#include <linux/init.h>
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#include <linux/module.h>
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#include <linux/slab.h>
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#include <linux/vmalloc.h>
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#include "dm.h"
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#define DM_MSG_PREFIX "region hash"
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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. dm_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. dm_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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* 'delayed_bios' 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 dm_region_hash {
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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 dm_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 mask;
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unsigned nr_buckets;
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unsigned prime;
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unsigned shift;
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struct list_head *buckets;
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unsigned max_recovery; /* Max # of regions to recover in parallel */
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spinlock_t region_lock;
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atomic_t recovery_in_flight;
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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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struct list_head failed_recovered_regions;
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/*
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* If there was a flush failure no regions can be marked clean.
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*/
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int flush_failure;
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void *context;
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sector_t target_begin;
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/* Callback function to schedule bios writes */
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void (*dispatch_bios)(void *context, struct bio_list *bios);
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/* Callback function to wakeup callers worker thread. */
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void (*wakeup_workers)(void *context);
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/* Callback function to wakeup callers recovery waiters. */
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void (*wakeup_all_recovery_waiters)(void *context);
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};
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struct dm_region {
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struct dm_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 region_t dm_rh_sector_to_region(struct dm_region_hash *rh, sector_t sector)
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{
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return sector >> rh->region_shift;
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}
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sector_t dm_rh_region_to_sector(struct dm_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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EXPORT_SYMBOL_GPL(dm_rh_region_to_sector);
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region_t dm_rh_bio_to_region(struct dm_region_hash *rh, struct bio *bio)
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{
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return dm_rh_sector_to_region(rh, bio->bi_sector - rh->target_begin);
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}
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EXPORT_SYMBOL_GPL(dm_rh_bio_to_region);
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void *dm_rh_region_context(struct dm_region *reg)
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{
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return reg->rh->context;
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}
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EXPORT_SYMBOL_GPL(dm_rh_region_context);
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region_t dm_rh_get_region_key(struct dm_region *reg)
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{
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return reg->key;
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}
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EXPORT_SYMBOL_GPL(dm_rh_get_region_key);
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sector_t dm_rh_get_region_size(struct dm_region_hash *rh)
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{
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return rh->region_size;
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}
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EXPORT_SYMBOL_GPL(dm_rh_get_region_size);
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/*
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* FIXME: shall we pass in a structure instead of all these args to
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* dm_region_hash_create()????
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*/
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#define RH_HASH_MULT 2654435387U
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#define RH_HASH_SHIFT 12
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#define MIN_REGIONS 64
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struct dm_region_hash *dm_region_hash_create(
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void *context, void (*dispatch_bios)(void *context,
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struct bio_list *bios),
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void (*wakeup_workers)(void *context),
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void (*wakeup_all_recovery_waiters)(void *context),
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sector_t target_begin, unsigned max_recovery,
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struct dm_dirty_log *log, uint32_t region_size,
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region_t nr_regions)
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{
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struct dm_region_hash *rh;
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unsigned 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 = kmalloc(sizeof(*rh), GFP_KERNEL);
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if (!rh) {
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DMERR("unable to allocate region hash memory");
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return ERR_PTR(-ENOMEM);
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}
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rh->context = context;
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rh->dispatch_bios = dispatch_bios;
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rh->wakeup_workers = wakeup_workers;
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rh->wakeup_all_recovery_waiters = wakeup_all_recovery_waiters;
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rh->target_begin = target_begin;
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rh->max_recovery = max_recovery;
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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->shift = RH_HASH_SHIFT;
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rh->prime = RH_HASH_MULT;
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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 bucket memory");
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kfree(rh);
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return ERR_PTR(-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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atomic_set(&rh->recovery_in_flight, 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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INIT_LIST_HEAD(&rh->failed_recovered_regions);
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rh->flush_failure = 0;
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rh->region_pool = mempool_create_kmalloc_pool(MIN_REGIONS,
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sizeof(struct dm_region));
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if (!rh->region_pool) {
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vfree(rh->buckets);
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kfree(rh);
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rh = ERR_PTR(-ENOMEM);
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}
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return rh;
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}
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EXPORT_SYMBOL_GPL(dm_region_hash_create);
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void dm_region_hash_destroy(struct dm_region_hash *rh)
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{
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unsigned h;
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struct dm_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,
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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_dirty_log_destroy(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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kfree(rh);
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}
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EXPORT_SYMBOL_GPL(dm_region_hash_destroy);
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struct dm_dirty_log *dm_rh_dirty_log(struct dm_region_hash *rh)
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{
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return rh->log;
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}
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EXPORT_SYMBOL_GPL(dm_rh_dirty_log);
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static unsigned rh_hash(struct dm_region_hash *rh, region_t region)
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{
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return (unsigned) ((region * rh->prime) >> rh->shift) & rh->mask;
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}
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static struct dm_region *__rh_lookup(struct dm_region_hash *rh, region_t region)
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{
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struct dm_region *reg;
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struct list_head *bucket = rh->buckets + rh_hash(rh, region);
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list_for_each_entry(reg, bucket, 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 dm_region_hash *rh, struct dm_region *reg)
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{
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list_add(®->hash_list, rh->buckets + rh_hash(rh, reg->key));
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}
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static struct dm_region *__rh_alloc(struct dm_region_hash *rh, region_t region)
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{
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struct dm_region *reg, *nreg;
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nreg = mempool_alloc(rh->region_pool, GFP_ATOMIC);
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if (unlikely(!nreg))
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nreg = kmalloc(sizeof(*nreg), GFP_NOIO | __GFP_NOFAIL);
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nreg->state = rh->log->type->in_sync(rh->log, region, 1) ?
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DM_RH_CLEAN : DM_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 == DM_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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return reg;
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}
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static struct dm_region *__rh_find(struct dm_region_hash *rh, region_t region)
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{
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struct dm_region *reg;
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reg = __rh_lookup(rh, region);
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if (!reg) {
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read_unlock(&rh->hash_lock);
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reg = __rh_alloc(rh, region);
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read_lock(&rh->hash_lock);
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}
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return reg;
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}
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int dm_rh_get_state(struct dm_region_hash *rh, region_t region, int may_block)
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{
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int r;
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struct dm_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 DM_RH_NOSYNC
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*/
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return r == 1 ? DM_RH_CLEAN : DM_RH_NOSYNC;
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}
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EXPORT_SYMBOL_GPL(dm_rh_get_state);
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static void complete_resync_work(struct dm_region *reg, int success)
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{
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struct dm_region_hash *rh = reg->rh;
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rh->log->type->set_region_sync(rh->log, reg->key, success);
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/*
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* Dispatch the bios before we call 'wake_up_all'.
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* This is important because if we are suspending,
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* we want to know that recovery is complete and
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* the work queue is flushed. If we wake_up_all
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* before we dispatch_bios (queue bios and call wake()),
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* then we risk suspending before the work queue
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* has been properly flushed.
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*/
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rh->dispatch_bios(rh->context, ®->delayed_bios);
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if (atomic_dec_and_test(&rh->recovery_in_flight))
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rh->wakeup_all_recovery_waiters(rh->context);
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up(&rh->recovery_count);
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}
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/* dm_rh_mark_nosync
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* @ms
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* @bio
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*
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* The bio was written on some mirror(s) but failed on other mirror(s).
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* We can successfully endio the bio but should avoid the region being
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* marked clean by setting the state DM_RH_NOSYNC.
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*
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* This function is _not_ safe in interrupt context!
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*/
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void dm_rh_mark_nosync(struct dm_region_hash *rh, struct bio *bio)
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{
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unsigned long flags;
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struct dm_dirty_log *log = rh->log;
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struct dm_region *reg;
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region_t region = dm_rh_bio_to_region(rh, bio);
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int recovering = 0;
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if (bio->bi_rw & REQ_FLUSH) {
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rh->flush_failure = 1;
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return;
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}
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/* We must inform the log that the sync count has changed. */
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log->type->set_region_sync(log, region, 0);
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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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/* region hash entry should exist because write was in-flight */
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BUG_ON(!reg);
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BUG_ON(!list_empty(®->list));
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spin_lock_irqsave(&rh->region_lock, flags);
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/*
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* Possible cases:
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* 1) DM_RH_DIRTY
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* 2) DM_RH_NOSYNC: was dirty, other preceding writes failed
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* 3) DM_RH_RECOVERING: flushing pending writes
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* Either case, the region should have not been connected to list.
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*/
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recovering = (reg->state == DM_RH_RECOVERING);
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reg->state = DM_RH_NOSYNC;
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BUG_ON(!list_empty(®->list));
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spin_unlock_irqrestore(&rh->region_lock, flags);
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if (recovering)
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complete_resync_work(reg, 0);
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}
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EXPORT_SYMBOL_GPL(dm_rh_mark_nosync);
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void dm_rh_update_states(struct dm_region_hash *rh, int errors_handled)
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{
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struct dm_region *reg, *next;
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LIST_HEAD(clean);
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LIST_HEAD(recovered);
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LIST_HEAD(failed_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_init(&rh->clean_regions, &clean);
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list_for_each_entry(reg, &clean, list)
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list_del(®->hash_list);
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}
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if (!list_empty(&rh->recovered_regions)) {
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list_splice_init(&rh->recovered_regions, &recovered);
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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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if (!list_empty(&rh->failed_recovered_regions)) {
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list_splice_init(&rh->failed_recovered_regions,
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&failed_recovered);
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list_for_each_entry(reg, &failed_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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complete_resync_work(reg, 1);
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mempool_free(reg, rh->region_pool);
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}
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list_for_each_entry_safe(reg, next, &failed_recovered, list) {
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complete_resync_work(reg, errors_handled ? 0 : 1);
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mempool_free(reg, rh->region_pool);
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}
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list_for_each_entry_safe(reg, next, &clean, list) {
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rh->log->type->clear_region(rh->log, reg->key);
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mempool_free(reg, rh->region_pool);
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}
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rh->log->type->flush(rh->log);
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}
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EXPORT_SYMBOL_GPL(dm_rh_update_states);
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static void rh_inc(struct dm_region_hash *rh, region_t region)
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{
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struct dm_region *reg;
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read_lock(&rh->hash_lock);
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reg = __rh_find(rh, region);
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spin_lock_irq(&rh->region_lock);
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atomic_inc(®->pending);
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if (reg->state == DM_RH_CLEAN) {
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reg->state = DM_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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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) {
|
|
if (bio->bi_rw & REQ_FLUSH)
|
|
continue;
|
|
rh_inc(rh, dm_rh_bio_to_region(rh, bio));
|
|
}
|
|
}
|
|
EXPORT_SYMBOL_GPL(dm_rh_inc_pending);
|
|
|
|
void dm_rh_dec(struct dm_region_hash *rh, region_t region)
|
|
{
|
|
unsigned long flags;
|
|
struct dm_region *reg;
|
|
int should_wake = 0;
|
|
|
|
read_lock(&rh->hash_lock);
|
|
reg = __rh_lookup(rh, region);
|
|
read_unlock(&rh->hash_lock);
|
|
|
|
spin_lock_irqsave(&rh->region_lock, flags);
|
|
if (atomic_dec_and_test(®->pending)) {
|
|
/*
|
|
* There is no pending I/O for this region.
|
|
* We can move the region to corresponding list for next action.
|
|
* At this point, the region is not yet connected to any list.
|
|
*
|
|
* If the state is DM_RH_NOSYNC, the region should be kept off
|
|
* from clean list.
|
|
* The hash entry for DM_RH_NOSYNC will remain in memory
|
|
* until the region is recovered or the map is reloaded.
|
|
*/
|
|
|
|
/* do nothing for DM_RH_NOSYNC */
|
|
if (unlikely(rh->flush_failure)) {
|
|
/*
|
|
* If a write flush failed some time ago, we
|
|
* don't know whether or not this write made it
|
|
* to the disk, so we must resync the device.
|
|
*/
|
|
reg->state = DM_RH_NOSYNC;
|
|
} else if (reg->state == DM_RH_RECOVERING) {
|
|
list_add_tail(®->list, &rh->quiesced_regions);
|
|
} else if (reg->state == DM_RH_DIRTY) {
|
|
reg->state = DM_RH_CLEAN;
|
|
list_add(®->list, &rh->clean_regions);
|
|
}
|
|
should_wake = 1;
|
|
}
|
|
spin_unlock_irqrestore(&rh->region_lock, flags);
|
|
|
|
if (should_wake)
|
|
rh->wakeup_workers(rh->context);
|
|
}
|
|
EXPORT_SYMBOL_GPL(dm_rh_dec);
|
|
|
|
/*
|
|
* Starts quiescing a region in preparation for recovery.
|
|
*/
|
|
static int __rh_recovery_prepare(struct dm_region_hash *rh)
|
|
{
|
|
int r;
|
|
region_t region;
|
|
struct dm_region *reg;
|
|
|
|
/*
|
|
* Ask the dirty log what's next.
|
|
*/
|
|
r = rh->log->type->get_resync_work(rh->log, ®ion);
|
|
if (r <= 0)
|
|
return r;
|
|
|
|
/*
|
|
* Get this region, and start it quiescing by setting the
|
|
* recovering flag.
|
|
*/
|
|
read_lock(&rh->hash_lock);
|
|
reg = __rh_find(rh, region);
|
|
read_unlock(&rh->hash_lock);
|
|
|
|
spin_lock_irq(&rh->region_lock);
|
|
reg->state = DM_RH_RECOVERING;
|
|
|
|
/* Already quiesced ? */
|
|
if (atomic_read(®->pending))
|
|
list_del_init(®->list);
|
|
else
|
|
list_move(®->list, &rh->quiesced_regions);
|
|
|
|
spin_unlock_irq(&rh->region_lock);
|
|
|
|
return 1;
|
|
}
|
|
|
|
void dm_rh_recovery_prepare(struct dm_region_hash *rh)
|
|
{
|
|
/* Extra reference to avoid race with dm_rh_stop_recovery */
|
|
atomic_inc(&rh->recovery_in_flight);
|
|
|
|
while (!down_trylock(&rh->recovery_count)) {
|
|
atomic_inc(&rh->recovery_in_flight);
|
|
if (__rh_recovery_prepare(rh) <= 0) {
|
|
atomic_dec(&rh->recovery_in_flight);
|
|
up(&rh->recovery_count);
|
|
break;
|
|
}
|
|
}
|
|
|
|
/* Drop the extra reference */
|
|
if (atomic_dec_and_test(&rh->recovery_in_flight))
|
|
rh->wakeup_all_recovery_waiters(rh->context);
|
|
}
|
|
EXPORT_SYMBOL_GPL(dm_rh_recovery_prepare);
|
|
|
|
/*
|
|
* Returns any quiesced regions.
|
|
*/
|
|
struct dm_region *dm_rh_recovery_start(struct dm_region_hash *rh)
|
|
{
|
|
struct dm_region *reg = NULL;
|
|
|
|
spin_lock_irq(&rh->region_lock);
|
|
if (!list_empty(&rh->quiesced_regions)) {
|
|
reg = list_entry(rh->quiesced_regions.next,
|
|
struct dm_region, list);
|
|
list_del_init(®->list); /* remove from the quiesced list */
|
|
}
|
|
spin_unlock_irq(&rh->region_lock);
|
|
|
|
return reg;
|
|
}
|
|
EXPORT_SYMBOL_GPL(dm_rh_recovery_start);
|
|
|
|
void dm_rh_recovery_end(struct dm_region *reg, int success)
|
|
{
|
|
struct dm_region_hash *rh = reg->rh;
|
|
|
|
spin_lock_irq(&rh->region_lock);
|
|
if (success)
|
|
list_add(®->list, ®->rh->recovered_regions);
|
|
else
|
|
list_add(®->list, ®->rh->failed_recovered_regions);
|
|
|
|
spin_unlock_irq(&rh->region_lock);
|
|
|
|
rh->wakeup_workers(rh->context);
|
|
}
|
|
EXPORT_SYMBOL_GPL(dm_rh_recovery_end);
|
|
|
|
/* Return recovery in flight count. */
|
|
int dm_rh_recovery_in_flight(struct dm_region_hash *rh)
|
|
{
|
|
return atomic_read(&rh->recovery_in_flight);
|
|
}
|
|
EXPORT_SYMBOL_GPL(dm_rh_recovery_in_flight);
|
|
|
|
int dm_rh_flush(struct dm_region_hash *rh)
|
|
{
|
|
return rh->log->type->flush(rh->log);
|
|
}
|
|
EXPORT_SYMBOL_GPL(dm_rh_flush);
|
|
|
|
void dm_rh_delay(struct dm_region_hash *rh, struct bio *bio)
|
|
{
|
|
struct dm_region *reg;
|
|
|
|
read_lock(&rh->hash_lock);
|
|
reg = __rh_find(rh, dm_rh_bio_to_region(rh, bio));
|
|
bio_list_add(®->delayed_bios, bio);
|
|
read_unlock(&rh->hash_lock);
|
|
}
|
|
EXPORT_SYMBOL_GPL(dm_rh_delay);
|
|
|
|
void dm_rh_stop_recovery(struct dm_region_hash *rh)
|
|
{
|
|
int i;
|
|
|
|
/* wait for any recovering regions */
|
|
for (i = 0; i < rh->max_recovery; i++)
|
|
down(&rh->recovery_count);
|
|
}
|
|
EXPORT_SYMBOL_GPL(dm_rh_stop_recovery);
|
|
|
|
void dm_rh_start_recovery(struct dm_region_hash *rh)
|
|
{
|
|
int i;
|
|
|
|
for (i = 0; i < rh->max_recovery; i++)
|
|
up(&rh->recovery_count);
|
|
|
|
rh->wakeup_workers(rh->context);
|
|
}
|
|
EXPORT_SYMBOL_GPL(dm_rh_start_recovery);
|
|
|
|
MODULE_DESCRIPTION(DM_NAME " region hash");
|
|
MODULE_AUTHOR("Joe Thornber/Heinz Mauelshagen <dm-devel@redhat.com>");
|
|
MODULE_LICENSE("GPL");
|