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dm cache: revert "remove remainder of distinct discard block size"
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This reverts commit 64ab346 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>
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Joe Thornber authored and Mike Snitzer committed Nov 10, 2014
1 parent 5f274d8 commit 1bad9bc
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Showing 4 changed files with 77 additions and 46 deletions.
11 changes: 11 additions & 0 deletions drivers/md/dm-cache-block-types.h
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Original file line number Diff line number Diff line change
Expand Up @@ -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)
{
Expand All @@ -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 */
34 changes: 17 additions & 17 deletions drivers/md/dm-cache-metadata.c
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Original file line number Diff line number Diff line change
Expand Up @@ -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;
Expand Down Expand Up @@ -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);
Expand Down Expand Up @@ -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));
Expand Down Expand Up @@ -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]);
Expand Down Expand Up @@ -797,15 +797,15 @@ int dm_cache_resize(struct dm_cache_metadata *cmd, dm_cblock_t new_cache_size)

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;
Expand All @@ -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;

Expand All @@ -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;

Expand All @@ -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);
Expand Down
6 changes: 3 additions & 3 deletions drivers/md/dm-cache-metadata.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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);
Expand Down
72 changes: 46 additions & 26 deletions drivers/md/dm-cache-target.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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
Expand Down Expand Up @@ -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;
Expand All @@ -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;
Expand Down Expand Up @@ -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,
Expand All @@ -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));
}
}

Expand Down Expand Up @@ -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);
}
Expand Down Expand Up @@ -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)) {
Expand Down Expand Up @@ -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;
}
Expand Down Expand Up @@ -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;
}
Expand Down Expand Up @@ -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)
Expand Down

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