dm cache: revert "remove remainder of distinct discard block size"

This reverts commit 64ab346a360a4b15c28fb8531918d4a01f4eabd9 because we
actually do want to allow the discard blocksize to be larger than the
cache blocksize.  Further dm-cache discard changes will make this
possible.

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

4 files changed, 77 insertions, 46 deletions

diff --git a/drivers/md/dm-cache-block-types.h b/drivers/md/dm-cache-block-types.h
index aac0e2df06be..bed4ad4e1b7c 100644
--- a/drivers/md/dm-cache-block-types.h
+++ b/drivers/md/dm-cache-block-types.h
@@ -19,6 +19,7 @@
 
 typedef dm_block_t __bitwise__ dm_oblock_t;
 typedef uint32_t __bitwise__ dm_cblock_t;
+typedef dm_block_t __bitwise__ dm_dblock_t;
 
 static inline dm_oblock_t to_oblock(dm_block_t b)
 {
@@ -40,4 +41,14 @@ static inline uint32_t from_cblock(dm_cblock_t b)
 	return (__force uint32_t) b;
 }
 
+static inline dm_dblock_t to_dblock(dm_block_t b)
+{
+	return (__force dm_dblock_t) b;
+}
+
+static inline dm_block_t from_dblock(dm_dblock_t b)
+{
+	return (__force dm_block_t) b;
+}
+
 #endif /* DM_CACHE_BLOCK_TYPES_H */
diff --git a/drivers/md/dm-cache-metadata.c b/drivers/md/dm-cache-metadata.c
index 06709257adde..9fc616c2755e 100644
--- a/drivers/md/dm-cache-metadata.c
+++ b/drivers/md/dm-cache-metadata.c
@@ -109,7 +109,7 @@ struct dm_cache_metadata {
 	dm_block_t discard_root;
 
 	sector_t discard_block_size;
-	dm_oblock_t discard_nr_blocks;
+	dm_dblock_t discard_nr_blocks;
 
 	sector_t data_block_size;
 	dm_cblock_t cache_blocks;
@@ -329,7 +329,7 @@ static int __write_initial_superblock(struct dm_cache_metadata *cmd)
 	disk_super->hint_root = cpu_to_le64(cmd->hint_root);
 	disk_super->discard_root = cpu_to_le64(cmd->discard_root);
 	disk_super->discard_block_size = cpu_to_le64(cmd->discard_block_size);
-	disk_super->discard_nr_blocks = cpu_to_le64(from_oblock(cmd->discard_nr_blocks));
+	disk_super->discard_nr_blocks = cpu_to_le64(from_dblock(cmd->discard_nr_blocks));
 	disk_super->metadata_block_size = cpu_to_le32(DM_CACHE_METADATA_BLOCK_SIZE);
 	disk_super->data_block_size = cpu_to_le32(cmd->data_block_size);
 	disk_super->cache_blocks = cpu_to_le32(0);
@@ -528,7 +528,7 @@ static void read_superblock_fields(struct dm_cache_metadata *cmd,
 	cmd->hint_root = le64_to_cpu(disk_super->hint_root);
 	cmd->discard_root = le64_to_cpu(disk_super->discard_root);
 	cmd->discard_block_size = le64_to_cpu(disk_super->discard_block_size);
-	cmd->discard_nr_blocks = to_oblock(le64_to_cpu(disk_super->discard_nr_blocks));
+	cmd->discard_nr_blocks = to_dblock(le64_to_cpu(disk_super->discard_nr_blocks));
 	cmd->data_block_size = le32_to_cpu(disk_super->data_block_size);
 	cmd->cache_blocks = to_cblock(le32_to_cpu(disk_super->cache_blocks));
 	strncpy(cmd->policy_name, disk_super->policy_name, sizeof(cmd->policy_name));
@@ -626,7 +626,7 @@ static int __commit_transaction(struct dm_cache_metadata *cmd,
 	disk_super->hint_root = cpu_to_le64(cmd->hint_root);
 	disk_super->discard_root = cpu_to_le64(cmd->discard_root);
 	disk_super->discard_block_size = cpu_to_le64(cmd->discard_block_size);
-	disk_super->discard_nr_blocks = cpu_to_le64(from_oblock(cmd->discard_nr_blocks));
+	disk_super->discard_nr_blocks = cpu_to_le64(from_dblock(cmd->discard_nr_blocks));
 	disk_super->cache_blocks = cpu_to_le32(from_cblock(cmd->cache_blocks));
 	strncpy(disk_super->policy_name, cmd->policy_name, sizeof(disk_super->policy_name));
 	disk_super->policy_version[0] = cpu_to_le32(cmd->policy_version[0]);
@@ -797,15 +797,15 @@ out:
 
 int dm_cache_discard_bitset_resize(struct dm_cache_metadata *cmd,
 				   sector_t discard_block_size,
-				   dm_oblock_t new_nr_entries)
+				   dm_dblock_t new_nr_entries)
 {
 	int r;
 
 	down_write(&cmd->root_lock);
 	r = dm_bitset_resize(&cmd->discard_info,
 			     cmd->discard_root,
-			     from_oblock(cmd->discard_nr_blocks),
-			     from_oblock(new_nr_entries),
+			     from_dblock(cmd->discard_nr_blocks),
+			     from_dblock(new_nr_entries),
 			     false, &cmd->discard_root);
 	if (!r) {
 		cmd->discard_block_size = discard_block_size;
@@ -818,28 +818,28 @@ int dm_cache_discard_bitset_resize(struct dm_cache_metadata *cmd,
 	return r;
 }
 
-static int __set_discard(struct dm_cache_metadata *cmd, dm_oblock_t b)
+static int __set_discard(struct dm_cache_metadata *cmd, dm_dblock_t b)
 {
 	return dm_bitset_set_bit(&cmd->discard_info, cmd->discard_root,
-				 from_oblock(b), &cmd->discard_root);
+				 from_dblock(b), &cmd->discard_root);
 }
 
-static int __clear_discard(struct dm_cache_metadata *cmd, dm_oblock_t b)
+static int __clear_discard(struct dm_cache_metadata *cmd, dm_dblock_t b)
 {
 	return dm_bitset_clear_bit(&cmd->discard_info, cmd->discard_root,
-				   from_oblock(b), &cmd->discard_root);
+				   from_dblock(b), &cmd->discard_root);
 }
 
-static int __is_discarded(struct dm_cache_metadata *cmd, dm_oblock_t b,
+static int __is_discarded(struct dm_cache_metadata *cmd, dm_dblock_t b,
 			  bool *is_discarded)
 {
 	return dm_bitset_test_bit(&cmd->discard_info, cmd->discard_root,
-				  from_oblock(b), &cmd->discard_root,
+				  from_dblock(b), &cmd->discard_root,
 				  is_discarded);
 }
 
 static int __discard(struct dm_cache_metadata *cmd,
-		     dm_oblock_t dblock, bool discard)
+		     dm_dblock_t dblock, bool discard)
 {
 	int r;
 
@@ -852,7 +852,7 @@ static int __discard(struct dm_cache_metadata *cmd,
 }
 
 int dm_cache_set_discard(struct dm_cache_metadata *cmd,
-			 dm_oblock_t dblock, bool discard)
+			 dm_dblock_t dblock, bool discard)
 {
 	int r;
 
@@ -870,8 +870,8 @@ static int __load_discards(struct dm_cache_metadata *cmd,
 	dm_block_t b;
 	bool discard;
 
-	for (b = 0; b < from_oblock(cmd->discard_nr_blocks); b++) {
-		dm_oblock_t dblock = to_oblock(b);
+	for (b = 0; b < from_dblock(cmd->discard_nr_blocks); b++) {
+		dm_dblock_t dblock = to_dblock(b);
 
 		if (cmd->clean_when_opened) {
 			r = __is_discarded(cmd, dblock, &discard);
diff --git a/drivers/md/dm-cache-metadata.h b/drivers/md/dm-cache-metadata.h
index 7383c90ccdb8..4ecc403be283 100644
--- a/drivers/md/dm-cache-metadata.h
+++ b/drivers/md/dm-cache-metadata.h
@@ -70,14 +70,14 @@ dm_cblock_t dm_cache_size(struct dm_cache_metadata *cmd);
 
 int dm_cache_discard_bitset_resize(struct dm_cache_metadata *cmd,
 				   sector_t discard_block_size,
-				   dm_oblock_t new_nr_entries);
+				   dm_dblock_t new_nr_entries);
 
 typedef int (*load_discard_fn)(void *context, sector_t discard_block_size,
-			       dm_oblock_t dblock, bool discarded);
+			       dm_dblock_t dblock, bool discarded);
 int dm_cache_load_discards(struct dm_cache_metadata *cmd,
 			   load_discard_fn fn, void *context);
 
-int dm_cache_set_discard(struct dm_cache_metadata *cmd, dm_oblock_t dblock, bool discard);
+int dm_cache_set_discard(struct dm_cache_metadata *cmd, dm_dblock_t dblock, bool discard);
 
 int dm_cache_remove_mapping(struct dm_cache_metadata *cmd, dm_cblock_t cblock);
 int dm_cache_insert_mapping(struct dm_cache_metadata *cmd, dm_cblock_t cblock, dm_oblock_t oblock);
diff --git a/drivers/md/dm-cache-target.c b/drivers/md/dm-cache-target.c
index 890e2fff4074..ced7fd4adddb 100644
--- a/drivers/md/dm-cache-target.c
+++ b/drivers/md/dm-cache-target.c
@@ -236,8 +236,9 @@ struct cache {
 	/*
 	 * origin_blocks entries, discarded if set.
 	 */
-	dm_oblock_t discard_nr_blocks;
+	dm_dblock_t discard_nr_blocks;
 	unsigned long *discard_bitset;
+	uint32_t discard_block_size;
 
 	/*
 	 * Rather than reconstructing the table line for the status we just
@@ -524,33 +525,48 @@ static dm_block_t block_div(dm_block_t b, uint32_t n)
 	return b;
 }
 
-static void set_discard(struct cache *cache, dm_oblock_t b)
+static dm_dblock_t oblock_to_dblock(struct cache *cache, dm_oblock_t oblock)
+{
+	uint32_t discard_blocks = cache->discard_block_size;
+	dm_block_t b = from_oblock(oblock);
+
+	if (!block_size_is_power_of_two(cache))
+		discard_blocks = discard_blocks / cache->sectors_per_block;
+	else
+		discard_blocks >>= cache->sectors_per_block_shift;
+
+	b = block_div(b, discard_blocks);
+
+	return to_dblock(b);
+}
+
+static void set_discard(struct cache *cache, dm_dblock_t b)
 {
 	unsigned long flags;
 
 	atomic_inc(&cache->stats.discard_count);
 
 	spin_lock_irqsave(&cache->lock, flags);
-	set_bit(from_oblock(b), cache->discard_bitset);
+	set_bit(from_dblock(b), cache->discard_bitset);
 	spin_unlock_irqrestore(&cache->lock, flags);
 }
 
-static void clear_discard(struct cache *cache, dm_oblock_t b)
+static void clear_discard(struct cache *cache, dm_dblock_t b)
 {
 	unsigned long flags;
 
 	spin_lock_irqsave(&cache->lock, flags);
-	clear_bit(from_oblock(b), cache->discard_bitset);
+	clear_bit(from_dblock(b), cache->discard_bitset);
 	spin_unlock_irqrestore(&cache->lock, flags);
 }
 
-static bool is_discarded(struct cache *cache, dm_oblock_t b)
+static bool is_discarded(struct cache *cache, dm_dblock_t b)
 {
 	int r;
 	unsigned long flags;
 
 	spin_lock_irqsave(&cache->lock, flags);
-	r = test_bit(from_oblock(b), cache->discard_bitset);
+	r = test_bit(from_dblock(b), cache->discard_bitset);
 	spin_unlock_irqrestore(&cache->lock, flags);
 
 	return r;
@@ -562,7 +578,8 @@ static bool is_discarded_oblock(struct cache *cache, dm_oblock_t b)
 	unsigned long flags;
 
 	spin_lock_irqsave(&cache->lock, flags);
-	r = test_bit(from_oblock(b), cache->discard_bitset);
+	r = test_bit(from_dblock(oblock_to_dblock(cache, b)),
+		     cache->discard_bitset);
 	spin_unlock_irqrestore(&cache->lock, flags);
 
 	return r;
@@ -687,7 +704,7 @@ static void remap_to_origin_clear_discard(struct cache *cache, struct bio *bio,
 	check_if_tick_bio_needed(cache, bio);
 	remap_to_origin(cache, bio);
 	if (bio_data_dir(bio) == WRITE)
-		clear_discard(cache, oblock);
+		clear_discard(cache, oblock_to_dblock(cache, oblock));
 }
 
 static void remap_to_cache_dirty(struct cache *cache, struct bio *bio,
@@ -697,7 +714,7 @@ static void remap_to_cache_dirty(struct cache *cache, struct bio *bio,
 	remap_to_cache(cache, bio, cblock);
 	if (bio_data_dir(bio) == WRITE) {
 		set_dirty(cache, oblock, cblock);
-		clear_discard(cache, oblock);
+		clear_discard(cache, oblock_to_dblock(cache, oblock));
 	}
 }
 
@@ -1301,14 +1318,14 @@ static void process_flush_bio(struct cache *cache, struct bio *bio)
 static void process_discard_bio(struct cache *cache, struct bio *bio)
 {
 	dm_block_t start_block = dm_sector_div_up(bio->bi_iter.bi_sector,
-						  cache->sectors_per_block);
+						  cache->discard_block_size);
 	dm_block_t end_block = bio_end_sector(bio);
 	dm_block_t b;
 
-	end_block = block_div(end_block, cache->sectors_per_block);
+	end_block = block_div(end_block, cache->discard_block_size);
 
 	for (b = start_block; b < end_block; b++)
-		set_discard(cache, to_oblock(b));
+		set_discard(cache, to_dblock(b));
 
 	bio_endio(bio, 0);
 }
@@ -2303,13 +2320,14 @@ static int cache_create(struct cache_args *ca, struct cache **result)
 	}
 	clear_bitset(cache->dirty_bitset, from_cblock(cache->cache_size));
 
-	cache->discard_nr_blocks = cache->origin_blocks;
-	cache->discard_bitset = alloc_bitset(from_oblock(cache->discard_nr_blocks));
+	cache->discard_block_size = cache->sectors_per_block;
+	cache->discard_nr_blocks = oblock_to_dblock(cache, cache->origin_blocks);
+	cache->discard_bitset = alloc_bitset(from_dblock(cache->discard_nr_blocks));
 	if (!cache->discard_bitset) {
 		*error = "could not allocate discard bitset";
 		goto bad;
 	}
-	clear_bitset(cache->discard_bitset, from_oblock(cache->discard_nr_blocks));
+	clear_bitset(cache->discard_bitset, from_dblock(cache->discard_nr_blocks));
 
 	cache->copier = dm_kcopyd_client_create(&dm_kcopyd_throttle);
 	if (IS_ERR(cache->copier)) {
@@ -2599,16 +2617,16 @@ static int write_discard_bitset(struct cache *cache)
 {
 	unsigned i, r;
 
-	r = dm_cache_discard_bitset_resize(cache->cmd, cache->sectors_per_block,
-					   cache->origin_blocks);
+	r = dm_cache_discard_bitset_resize(cache->cmd, cache->discard_block_size,
+					   cache->discard_nr_blocks);
 	if (r) {
 		DMERR("could not resize on-disk discard bitset");
 		return r;
 	}
 
-	for (i = 0; i < from_oblock(cache->discard_nr_blocks); i++) {
-		r = dm_cache_set_discard(cache->cmd, to_oblock(i),
-					 is_discarded(cache, to_oblock(i)));
+	for (i = 0; i < from_dblock(cache->discard_nr_blocks); i++) {
+		r = dm_cache_set_discard(cache->cmd, to_dblock(i),
+					 is_discarded(cache, to_dblock(i)));
 		if (r)
 			return r;
 	}
@@ -2681,14 +2699,16 @@ static int load_mapping(void *context, dm_oblock_t oblock, dm_cblock_t cblock,
 }
 
 static int load_discard(void *context, sector_t discard_block_size,
-			dm_oblock_t oblock, bool discard)
+			dm_dblock_t dblock, bool discard)
 {
 	struct cache *cache = context;
 
+	/* FIXME: handle mis-matched block size */
+
 	if (discard)
-		set_discard(cache, oblock);
+		set_discard(cache, dblock);
 	else
-		clear_discard(cache, oblock);
+		clear_discard(cache, dblock);
 
 	return 0;
 }
@@ -3079,8 +3099,8 @@ static void set_discard_limits(struct cache *cache, struct queue_limits *limits)
 	/*
 	 * FIXME: these limits may be incompatible with the cache device
 	 */
-	limits->max_discard_sectors = cache->sectors_per_block;
-	limits->discard_granularity = cache->sectors_per_block << SECTOR_SHIFT;
+	limits->max_discard_sectors = cache->discard_block_size;
+	limits->discard_granularity = cache->discard_block_size << SECTOR_SHIFT;
 }
 
 static void cache_io_hints(struct dm_target *ti, struct queue_limits *limits)