From 532906aa7f9656209f30f08dfadd328fc1bc6912 Mon Sep 17 00:00:00 2001 From: Joe Thornber Date: Fri, 8 Nov 2013 16:36:17 +0000 Subject: [PATCH] dm cache: add remove_cblock method to policy interface Implement policy_remove_cblock() and add remove_cblock method to the mq policy. These methods will be used by the following cache block invalidation patch which adds the 'invalidate_cblocks' message to the cache core. Also, update some comments in dm-cache-policy.h Signed-off-by: Joe Thornber Signed-off-by: Mike Snitzer --- drivers/md/dm-cache-policy-internal.h | 5 ++++ drivers/md/dm-cache-policy-mq.c | 35 +++++++++++++++++++++++++++ drivers/md/dm-cache-policy.h | 21 +++++++++++++--- 3 files changed, 57 insertions(+), 4 deletions(-) diff --git a/drivers/md/dm-cache-policy-internal.h b/drivers/md/dm-cache-policy-internal.h index a75f7e7498eb..2256a1f24f73 100644 --- a/drivers/md/dm-cache-policy-internal.h +++ b/drivers/md/dm-cache-policy-internal.h @@ -64,6 +64,11 @@ static inline void policy_remove_mapping(struct dm_cache_policy *p, dm_oblock_t p->remove_mapping(p, oblock); } +static inline int policy_remove_cblock(struct dm_cache_policy *p, dm_cblock_t cblock) +{ + return p->remove_cblock(p, cblock); +} + static inline void policy_force_mapping(struct dm_cache_policy *p, dm_oblock_t current_oblock, dm_oblock_t new_oblock) { diff --git a/drivers/md/dm-cache-policy-mq.c b/drivers/md/dm-cache-policy-mq.c index 782bf854666a..7209fab8b8ed 100644 --- a/drivers/md/dm-cache-policy-mq.c +++ b/drivers/md/dm-cache-policy-mq.c @@ -304,6 +304,15 @@ static void free_entry(struct entry_pool *ep, struct entry *e) list_add(&e->list, &ep->free); } +/* + * Returns NULL if the entry is free. + */ +static struct entry *epool_find(struct entry_pool *ep, dm_cblock_t cblock) +{ + struct entry *e = ep->entries + from_cblock(cblock); + return e->hlist.pprev ? e : NULL; +} + static bool epool_empty(struct entry_pool *ep) { return list_empty(&ep->free); @@ -1020,6 +1029,31 @@ static void mq_remove_mapping(struct dm_cache_policy *p, dm_oblock_t oblock) mutex_unlock(&mq->lock); } +static int __remove_cblock(struct mq_policy *mq, dm_cblock_t cblock) +{ + struct entry *e = epool_find(&mq->cache_pool, cblock); + + if (!e) + return -ENODATA; + + del(mq, e); + free_entry(&mq->cache_pool, e); + + return 0; +} + +static int mq_remove_cblock(struct dm_cache_policy *p, dm_cblock_t cblock) +{ + int r; + struct mq_policy *mq = to_mq_policy(p); + + mutex_lock(&mq->lock); + r = __remove_cblock(mq, cblock); + mutex_unlock(&mq->lock); + + return r; +} + static int __mq_writeback_work(struct mq_policy *mq, dm_oblock_t *oblock, dm_cblock_t *cblock) { @@ -1139,6 +1173,7 @@ static void init_policy_functions(struct mq_policy *mq) mq->policy.load_mapping = mq_load_mapping; mq->policy.walk_mappings = mq_walk_mappings; mq->policy.remove_mapping = mq_remove_mapping; + mq->policy.remove_cblock = mq_remove_cblock; mq->policy.writeback_work = mq_writeback_work; mq->policy.force_mapping = mq_force_mapping; mq->policy.residency = mq_residency; diff --git a/drivers/md/dm-cache-policy.h b/drivers/md/dm-cache-policy.h index 33369ca9614f..052c00a84a5c 100644 --- a/drivers/md/dm-cache-policy.h +++ b/drivers/md/dm-cache-policy.h @@ -135,9 +135,6 @@ struct dm_cache_policy { */ int (*lookup)(struct dm_cache_policy *p, dm_oblock_t oblock, dm_cblock_t *cblock); - /* - * oblock must be a mapped block. Must not block. - */ void (*set_dirty)(struct dm_cache_policy *p, dm_oblock_t oblock); void (*clear_dirty)(struct dm_cache_policy *p, dm_oblock_t oblock); @@ -159,8 +156,24 @@ struct dm_cache_policy { void (*force_mapping)(struct dm_cache_policy *p, dm_oblock_t current_oblock, dm_oblock_t new_oblock); - int (*writeback_work)(struct dm_cache_policy *p, dm_oblock_t *oblock, dm_cblock_t *cblock); + /* + * This is called via the invalidate_cblocks message. It is + * possible the particular cblock has already been removed due to a + * write io in passthrough mode. In which case this should return + * -ENODATA. + */ + int (*remove_cblock)(struct dm_cache_policy *p, dm_cblock_t cblock); + /* + * Provide a dirty block to be written back by the core target. + * + * Returns: + * + * 0 and @cblock,@oblock: block to write back provided + * + * -ENODATA: no dirty blocks available + */ + int (*writeback_work)(struct dm_cache_policy *p, dm_oblock_t *oblock, dm_cblock_t *cblock); /* * How full is the cache?