fb4100ae7f
There is a race between a policy deciding to replace a cache entry, the core target writing back any dirty data from this block, and other IO threads doing IO to the same block. This sort of problem is avoided most of the time by the core target grabbing a bio prison cell before making the request to the policy. But for a demotion the core target doesn't know which block will be demoted, so can't do this in advance. Fix this demotion race by introducing a callback to the policy interface that allows the policy to grab the cell on behalf of the core target. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Cc: stable@vger.kernel.org
133 lines
3.6 KiB
C
133 lines
3.6 KiB
C
/*
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* Copyright (C) 2012 Red Hat. 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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#ifndef DM_CACHE_POLICY_INTERNAL_H
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#define DM_CACHE_POLICY_INTERNAL_H
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#include "dm-cache-policy.h"
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/*----------------------------------------------------------------*/
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/*
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* Little inline functions that simplify calling the policy methods.
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*/
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static inline int policy_map(struct dm_cache_policy *p, dm_oblock_t oblock,
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bool can_block, bool can_migrate, bool discarded_oblock,
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struct bio *bio, struct policy_locker *locker,
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struct policy_result *result)
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{
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return p->map(p, oblock, can_block, can_migrate, discarded_oblock, bio, locker, result);
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}
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static inline int policy_lookup(struct dm_cache_policy *p, dm_oblock_t oblock, dm_cblock_t *cblock)
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{
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BUG_ON(!p->lookup);
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return p->lookup(p, oblock, cblock);
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}
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static inline void policy_set_dirty(struct dm_cache_policy *p, dm_oblock_t oblock)
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{
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if (p->set_dirty)
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p->set_dirty(p, oblock);
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}
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static inline void policy_clear_dirty(struct dm_cache_policy *p, dm_oblock_t oblock)
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{
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if (p->clear_dirty)
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p->clear_dirty(p, oblock);
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}
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static inline int policy_load_mapping(struct dm_cache_policy *p,
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dm_oblock_t oblock, dm_cblock_t cblock,
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uint32_t hint, bool hint_valid)
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{
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return p->load_mapping(p, oblock, cblock, hint, hint_valid);
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}
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static inline int policy_walk_mappings(struct dm_cache_policy *p,
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policy_walk_fn fn, void *context)
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{
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return p->walk_mappings ? p->walk_mappings(p, fn, context) : 0;
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}
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static inline int policy_writeback_work(struct dm_cache_policy *p,
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dm_oblock_t *oblock,
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dm_cblock_t *cblock)
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{
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return p->writeback_work ? p->writeback_work(p, oblock, cblock) : -ENOENT;
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}
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static inline void policy_remove_mapping(struct dm_cache_policy *p, dm_oblock_t oblock)
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{
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p->remove_mapping(p, oblock);
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}
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static inline int policy_remove_cblock(struct dm_cache_policy *p, dm_cblock_t cblock)
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{
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return p->remove_cblock(p, cblock);
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}
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static inline void policy_force_mapping(struct dm_cache_policy *p,
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dm_oblock_t current_oblock, dm_oblock_t new_oblock)
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{
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return p->force_mapping(p, current_oblock, new_oblock);
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}
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static inline dm_cblock_t policy_residency(struct dm_cache_policy *p)
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{
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return p->residency(p);
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}
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static inline void policy_tick(struct dm_cache_policy *p)
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{
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if (p->tick)
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return p->tick(p);
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}
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static inline int policy_emit_config_values(struct dm_cache_policy *p, char *result, unsigned maxlen)
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{
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ssize_t sz = 0;
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if (p->emit_config_values)
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return p->emit_config_values(p, result, maxlen);
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DMEMIT("0");
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return 0;
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}
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static inline int policy_set_config_value(struct dm_cache_policy *p,
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const char *key, const char *value)
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{
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return p->set_config_value ? p->set_config_value(p, key, value) : -EINVAL;
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}
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/*----------------------------------------------------------------*/
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/*
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* Creates a new cache policy given a policy name, a cache size, an origin size and the block size.
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*/
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struct dm_cache_policy *dm_cache_policy_create(const char *name, dm_cblock_t cache_size,
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sector_t origin_size, sector_t block_size);
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/*
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* Destroys the policy. This drops references to the policy module as well
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* as calling it's destroy method. So always use this rather than calling
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* the policy->destroy method directly.
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*/
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void dm_cache_policy_destroy(struct dm_cache_policy *p);
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/*
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* In case we've forgotten.
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*/
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const char *dm_cache_policy_get_name(struct dm_cache_policy *p);
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const unsigned *dm_cache_policy_get_version(struct dm_cache_policy *p);
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size_t dm_cache_policy_get_hint_size(struct dm_cache_policy *p);
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/*----------------------------------------------------------------*/
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#endif /* DM_CACHE_POLICY_INTERNAL_H */
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