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 <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>

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 <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Joe Thornber · Mike Snitzer
1 parent 633618e335
Showing 3 changed files with 57 additions and 4 deletions Side-by-side Diff
drivers/md/dm-cache-policy-internal.h
drivers/md/dm-cache-policy-mq.c
drivers/md/dm-cache-policy.h
@@ -64,6 +64,11 @@
 	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)
 {
@@ -304,6 +304,15 @@
 	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 @@
 	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 @@
 	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;
@@ -135,9 +135,6 @@
 	 */
 	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 @@
 	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?
...	...	@@ -64,6 +64,11 @@
64	64	p->remove_mapping(p, oblock);
65	65	}
66	66
	67	+static inline int policy_remove_cblock(struct dm_cache_policy *p, dm_cblock_t cblock)
	68	+{
	69	+ return p->remove_cblock(p, cblock);
	70	+}
	71	+
67	72	static inline void policy_force_mapping(struct dm_cache_policy *p,
68	73	dm_oblock_t current_oblock, dm_oblock_t new_oblock)
69	74	{
...	...	@@ -304,6 +304,15 @@
304	304	list_add(&e->list, &ep->free);
305	305	}
306	306
	307	+/*
	308	+ * Returns NULL if the entry is free.
	309	+ */
	310	+static struct entry epool_find(struct entry_pool ep, dm_cblock_t cblock)
	311	+{
	312	+ struct entry *e = ep->entries + from_cblock(cblock);
	313	+ return e->hlist.pprev ? e : NULL;
	314	+}
	315	+
307	316	static bool epool_empty(struct entry_pool *ep)
308	317	{
309	318	return list_empty(&ep->free);
...	...	@@ -1020,6 +1029,31 @@
1020	1029	mutex_unlock(&mq->lock);
1021	1030	}
1022	1031
	1032	+static int __remove_cblock(struct mq_policy *mq, dm_cblock_t cblock)
	1033	+{
	1034	+ struct entry *e = epool_find(&mq->cache_pool, cblock);
	1035	+
	1036	+ if (!e)
	1037	+ return -ENODATA;
	1038	+
	1039	+ del(mq, e);
	1040	+ free_entry(&mq->cache_pool, e);
	1041	+
	1042	+ return 0;
	1043	+}
	1044	+
	1045	+static int mq_remove_cblock(struct dm_cache_policy *p, dm_cblock_t cblock)
	1046	+{
	1047	+ int r;
	1048	+ struct mq_policy *mq = to_mq_policy(p);
	1049	+
	1050	+ mutex_lock(&mq->lock);
	1051	+ r = __remove_cblock(mq, cblock);
	1052	+ mutex_unlock(&mq->lock);
	1053	+
	1054	+ return r;
	1055	+}
	1056	+
1023	1057	static int __mq_writeback_work(struct mq_policy mq, dm_oblock_t oblock,
1024	1058	dm_cblock_t *cblock)
1025	1059	{
...	...	@@ -1139,6 +1173,7 @@
1139	1173	mq->policy.load_mapping = mq_load_mapping;
1140	1174	mq->policy.walk_mappings = mq_walk_mappings;
1141	1175	mq->policy.remove_mapping = mq_remove_mapping;
	1176	+ mq->policy.remove_cblock = mq_remove_cblock;
1142	1177	mq->policy.writeback_work = mq_writeback_work;
1143	1178	mq->policy.force_mapping = mq_force_mapping;
1144	1179	mq->policy.residency = mq_residency;
...	...	@@ -135,9 +135,6 @@
135	135	*/
136	136	int (lookup)(struct dm_cache_policy p, dm_oblock_t oblock, dm_cblock_t *cblock);
137	137
138		- /*
139		- * oblock must be a mapped block. Must not block.
140		- */
141	138	void (set_dirty)(struct dm_cache_policy p, dm_oblock_t oblock);
142	139	void (clear_dirty)(struct dm_cache_policy p, dm_oblock_t oblock);
143	140
144	141
...	...	@@ -159,8 +156,24 @@
159	156	void (force_mapping)(struct dm_cache_policy p, dm_oblock_t current_oblock,
160	157	dm_oblock_t new_oblock);
161	158
162		- int (writeback_work)(struct dm_cache_policy p, dm_oblock_t oblock, dm_cblock_t cblock);
	159	+ /*
	160	+ * This is called via the invalidate_cblocks message. It is
	161	+ * possible the particular cblock has already been removed due to a
	162	+ * write io in passthrough mode. In which case this should return
	163	+ * -ENODATA.
	164	+ */
	165	+ int (remove_cblock)(struct dm_cache_policy p, dm_cblock_t cblock);
163	166
	167	+ /*
	168	+ * Provide a dirty block to be written back by the core target.
	169	+ *
	170	+ * Returns:
	171	+ *
	172	+ * 0 and @cblock,@oblock: block to write back provided
	173	+ *
	174	+ * -ENODATA: no dirty blocks available
	175	+ */
	176	+ int (writeback_work)(struct dm_cache_policy p, dm_oblock_t oblock, dm_cblock_t cblock);
164	177
165	178	/*
166	179	* How full is the cache?