dm cache: remove remainder of distinct discard block size

Discard block size not being equal to cache block size causes data
corruption by erroneously avoiding migrations in issue_copy() because
the discard state is being cleared for a group of cache blocks when it
should not.

Completely remove all code that enabled a distinction between the
cache block size and discard block size.

Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

4 files changed, 46 insertions, 77 deletions

diff --git a/drivers/md/dm-cache-block-types.h b/drivers/md/dm-cache-block-types.h
index bed4ad4e1b7c..aac0e2df06be 100644
--- a/drivers/md/dm-cache-block-types.h
+++ b/drivers/md/dm-cache-block-types.h
@@ -19,7 +19,6 @@
 
 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)
 {
@@ -41,14 +40,4 @@ 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 9ef0752e8a08..cbd568a3a579 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_dblock_t discard_nr_blocks;
+        dm_oblock_t discard_nr_blocks;
 
         sector_t data_block_size;
         dm_cblock_t cache_blocks;
@@ -302,7 +302,7 @@ 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_dblock(cmd->discard_nr_blocks));
+        disk_super->discard_nr_blocks = cpu_to_le64(from_oblock(cmd->discard_nr_blocks));
         disk_super->metadata_block_size = cpu_to_le32(DM_CACHE_METADATA_BLOCK_SIZE >> SECTOR_SHIFT);
         disk_super->data_block_size = cpu_to_le32(cmd->data_block_size);
         disk_super->cache_blocks = cpu_to_le32(0);
@@ -496,7 +496,7 @@ 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_dblock(le64_to_cpu(disk_super->discard_nr_blocks));
+        cmd->discard_nr_blocks = to_oblock(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));
@@ -594,7 +594,7 @@ 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_dblock(cmd->discard_nr_blocks));
+        disk_super->discard_nr_blocks = cpu_to_le64(from_oblock(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]);
@@ -771,15 +771,15 @@ out:
 
 int dm_cache_discard_bitset_resize(struct dm_cache_metadata *cmd,
                                    sector_t discard_block_size,
-                                   dm_dblock_t new_nr_entries)
+                                   dm_oblock_t new_nr_entries)
 {
         int r;
 
         down_write(&cmd->root_lock);
         r = dm_bitset_resize(&cmd->discard_info,
                              cmd->discard_root,
-                             from_dblock(cmd->discard_nr_blocks),
-                             from_dblock(new_nr_entries),
+                             from_oblock(cmd->discard_nr_blocks),
+                             from_oblock(new_nr_entries),
                              false, &cmd->discard_root);
         if (!r) {
                 cmd->discard_block_size = discard_block_size;
@@ -792,28 +792,28 @@ int dm_cache_discard_bitset_resize(struct dm_cache_metadata *cmd,
         return r;
 }
 
-static int __set_discard(struct dm_cache_metadata *cmd, dm_dblock_t b)
+static int __set_discard(struct dm_cache_metadata *cmd, dm_oblock_t b)
 {
         return dm_bitset_set_bit(&cmd->discard_info, cmd->discard_root,
-                                 from_dblock(b), &cmd->discard_root);
+                                 from_oblock(b), &cmd->discard_root);
 }
 
-static int __clear_discard(struct dm_cache_metadata *cmd, dm_dblock_t b)
+static int __clear_discard(struct dm_cache_metadata *cmd, dm_oblock_t b)
 {
         return dm_bitset_clear_bit(&cmd->discard_info, cmd->discard_root,
-                                   from_dblock(b), &cmd->discard_root);
+                                   from_oblock(b), &cmd->discard_root);
 }
 
-static int __is_discarded(struct dm_cache_metadata *cmd, dm_dblock_t b,
+static int __is_discarded(struct dm_cache_metadata *cmd, dm_oblock_t b,
                           bool *is_discarded)
 {
         return dm_bitset_test_bit(&cmd->discard_info, cmd->discard_root,
-                                  from_dblock(b), &cmd->discard_root,
+                                  from_oblock(b), &cmd->discard_root,
                                   is_discarded);
 }
 
 static int __discard(struct dm_cache_metadata *cmd,
-                     dm_dblock_t dblock, bool discard)
+                     dm_oblock_t dblock, bool discard)
 {
         int r;
 
@@ -826,7 +826,7 @@ static int __discard(struct dm_cache_metadata *cmd,
 }
 
 int dm_cache_set_discard(struct dm_cache_metadata *cmd,
-                         dm_dblock_t dblock, bool discard)
+                         dm_oblock_t dblock, bool discard)
 {
         int r;
 
@@ -844,8 +844,8 @@ static int __load_discards(struct dm_cache_metadata *cmd,
         dm_block_t b;
         bool discard;
 
-        for (b = 0; b < from_dblock(cmd->discard_nr_blocks); b++) {
-                dm_dblock_t dblock = to_dblock(b);
+        for (b = 0; b < from_oblock(cmd->discard_nr_blocks); b++) {
+                dm_oblock_t dblock = to_oblock(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 cd906f14f98d..ce8468bb616e 100644
--- a/drivers/md/dm-cache-metadata.h
+++ b/drivers/md/dm-cache-metadata.h
@@ -72,14 +72,14 @@ 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_dblock_t new_nr_entries);
+                                   dm_oblock_t new_nr_entries);
 
 typedef int (*load_discard_fn)(void *context, sector_t discard_block_size,
-                               dm_dblock_t dblock, bool discarded);
+                               dm_oblock_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_dblock_t dblock, bool discard);
+int dm_cache_set_discard(struct dm_cache_metadata *cmd, dm_oblock_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 bccb7ae34e61..8534679918f4 100644
--- a/drivers/md/dm-cache-target.c
+++ b/drivers/md/dm-cache-target.c
@@ -237,9 +237,8 @@ struct cache {
         /*
          * origin_blocks entries, discarded if set.
          */
-        dm_dblock_t discard_nr_blocks;
+        dm_oblock_t discard_nr_blocks;
         unsigned long *discard_bitset;
-        uint32_t discard_block_size;
 
         /*
          * Rather than reconstructing the table line for the status we just
@@ -526,48 +525,33 @@ static dm_block_t block_div(dm_block_t b, uint32_t n)
         return 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)
+static void set_discard(struct cache *cache, dm_oblock_t b)
 {
         unsigned long flags;
 
         atomic_inc(&cache->stats.discard_count);
 
         spin_lock_irqsave(&cache->lock, flags);
-        set_bit(from_dblock(b), cache->discard_bitset);
+        set_bit(from_oblock(b), cache->discard_bitset);
         spin_unlock_irqrestore(&cache->lock, flags);
 }
 
-static void clear_discard(struct cache *cache, dm_dblock_t b)
+static void clear_discard(struct cache *cache, dm_oblock_t b)
 {
         unsigned long flags;
 
         spin_lock_irqsave(&cache->lock, flags);
-        clear_bit(from_dblock(b), cache->discard_bitset);
+        clear_bit(from_oblock(b), cache->discard_bitset);
         spin_unlock_irqrestore(&cache->lock, flags);
 }
 
-static bool is_discarded(struct cache *cache, dm_dblock_t b)
+static bool is_discarded(struct cache *cache, dm_oblock_t b)
 {
         int r;
         unsigned long flags;
 
         spin_lock_irqsave(&cache->lock, flags);
-        r = test_bit(from_dblock(b), cache->discard_bitset);
+        r = test_bit(from_oblock(b), cache->discard_bitset);
         spin_unlock_irqrestore(&cache->lock, flags);
 
         return r;
@@ -579,8 +563,7 @@ 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_dblock(oblock_to_dblock(cache, b)),
-                     cache->discard_bitset);
+        r = test_bit(from_oblock(b), cache->discard_bitset);
         spin_unlock_irqrestore(&cache->lock, flags);
 
         return r;
@@ -705,7 +688,7 @@ 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_to_dblock(cache, oblock));
+                clear_discard(cache, oblock);
 }
 
 static void remap_to_cache_dirty(struct cache *cache, struct bio *bio,
@@ -715,7 +698,7 @@ 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_to_dblock(cache, oblock));
+                clear_discard(cache, oblock);
         }
 }
 
@@ -1288,14 +1271,14 @@ 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->discard_block_size);
+                                                  cache->sectors_per_block);
         dm_block_t end_block = bio_end_sector(bio);
         dm_block_t b;
 
-        end_block = block_div(end_block, cache->discard_block_size);
+        end_block = block_div(end_block, cache->sectors_per_block);
 
         for (b = start_block; b < end_block; b++)
-                set_discard(cache, to_dblock(b));
+                set_discard(cache, to_oblock(b));
 
         bio_endio(bio, 0);
 }
@@ -2292,14 +2275,13 @@ static int cache_create(struct cache_args *ca, struct cache **result)
         }
         clear_bitset(cache->dirty_bitset, from_cblock(cache->cache_size));
 
-        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));
+        cache->discard_nr_blocks = cache->origin_blocks;
+        cache->discard_bitset = alloc_bitset(from_oblock(cache->discard_nr_blocks));
         if (!cache->discard_bitset) {
                 *error = "could not allocate discard bitset";
                 goto bad;
         }
-        clear_bitset(cache->discard_bitset, from_dblock(cache->discard_nr_blocks));
+        clear_bitset(cache->discard_bitset, from_oblock(cache->discard_nr_blocks));
 
         cache->copier = dm_kcopyd_client_create(&dm_kcopyd_throttle);
         if (IS_ERR(cache->copier)) {
@@ -2583,16 +2565,16 @@ static int write_discard_bitset(struct cache *cache)
 {
         unsigned i, r;
 
-        r = dm_cache_discard_bitset_resize(cache->cmd, cache->discard_block_size,
-                                           cache->discard_nr_blocks);
+        r = dm_cache_discard_bitset_resize(cache->cmd, cache->sectors_per_block,
+                                           cache->origin_blocks);
         if (r) {
                 DMERR("could not resize on-disk discard bitset");
                 return r;
         }
 
-        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)));
+        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)));
                 if (r)
                         return r;
         }
@@ -2689,16 +2671,14 @@ 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_dblock_t dblock, bool discard)
+                        dm_oblock_t oblock, bool discard)
 {
         struct cache *cache = context;
 
-        /* FIXME: handle mis-matched block size */
-
         if (discard)
-                set_discard(cache, dblock);
+                set_discard(cache, oblock);
         else
-                clear_discard(cache, dblock);
+                clear_discard(cache, oblock);
 
         return 0;
 }
@@ -3089,8 +3069,8 @@ 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->discard_block_size;
-        limits->discard_granularity = cache->discard_block_size << SECTOR_SHIFT;
+        limits->max_discard_sectors = cache->sectors_per_block;
+        limits->discard_granularity = cache->sectors_per_block << SECTOR_SHIFT;
 }
 
 static void cache_io_hints(struct dm_target *ti, struct queue_limits *limits)