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authorJoe Thornber <ejt@redhat.com>2016-09-22 13:15:21 +0300
committerMike Snitzer <snitzer@redhat.com>2017-02-16 21:12:47 +0300
commit629d0a8a1a104187db8fbf966e4cc5cfb6aa9a3c (patch)
treedf900a59355073aca34dd8de83d4ca631428cd6e /drivers/md/dm-cache-metadata.c
parentae4a46a1f60942263d6fd119fe1da49bb16d2bd5 (diff)
downloadlinux-629d0a8a1a104187db8fbf966e4cc5cfb6aa9a3c.tar.xz
dm cache metadata: add "metadata2" feature
If "metadata2" is provided as a table argument when creating/loading a cache target a more compact metadata format, with separate dirty bits, is used. "metadata2" improves speed of shutting down a cache target. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Diffstat (limited to 'drivers/md/dm-cache-metadata.c')
-rw-r--r--drivers/md/dm-cache-metadata.c278
1 files changed, 245 insertions, 33 deletions
diff --git a/drivers/md/dm-cache-metadata.c b/drivers/md/dm-cache-metadata.c
index 9364a02e1646..0610be7846dc 100644
--- a/drivers/md/dm-cache-metadata.c
+++ b/drivers/md/dm-cache-metadata.c
@@ -25,7 +25,7 @@
* defines a range of metadata versions that this module can handle.
*/
#define MIN_CACHE_VERSION 1
-#define MAX_CACHE_VERSION 1
+#define MAX_CACHE_VERSION 2
#define CACHE_METADATA_CACHE_SIZE 64
@@ -55,6 +55,7 @@ enum mapping_bits {
/*
* The data on the cache is different from that on the origin.
+ * This flag is only used by metadata format 1.
*/
M_DIRTY = 2
};
@@ -93,12 +94,18 @@ struct cache_disk_superblock {
__le32 write_misses;
__le32 policy_version[CACHE_POLICY_VERSION_SIZE];
+
+ /*
+ * Metadata format 2 fields.
+ */
+ __le64 dirty_root;
} __packed;
struct dm_cache_metadata {
atomic_t ref_count;
struct list_head list;
+ unsigned version;
struct block_device *bdev;
struct dm_block_manager *bm;
struct dm_space_map *metadata_sm;
@@ -142,11 +149,18 @@ struct dm_cache_metadata {
bool fail_io:1;
/*
+ * Metadata format 2 fields.
+ */
+ dm_block_t dirty_root;
+ struct dm_disk_bitset dirty_info;
+
+ /*
* These structures are used when loading metadata. They're too
* big to put on the stack.
*/
struct dm_array_cursor mapping_cursor;
struct dm_array_cursor hint_cursor;
+ struct dm_bitset_cursor dirty_cursor;
};
/*-------------------------------------------------------------------
@@ -170,6 +184,7 @@ static void sb_prepare_for_write(struct dm_block_validator *v,
static int check_metadata_version(struct cache_disk_superblock *disk_super)
{
uint32_t metadata_version = le32_to_cpu(disk_super->version);
+
if (metadata_version < MIN_CACHE_VERSION || metadata_version > MAX_CACHE_VERSION) {
DMERR("Cache metadata version %u found, but only versions between %u and %u supported.",
metadata_version, MIN_CACHE_VERSION, MAX_CACHE_VERSION);
@@ -310,6 +325,11 @@ static void __copy_sm_root(struct dm_cache_metadata *cmd,
sizeof(cmd->metadata_space_map_root));
}
+static bool separate_dirty_bits(struct dm_cache_metadata *cmd)
+{
+ return cmd->version >= 2;
+}
+
static int __write_initial_superblock(struct dm_cache_metadata *cmd)
{
int r;
@@ -341,7 +361,7 @@ static int __write_initial_superblock(struct dm_cache_metadata *cmd)
disk_super->flags = 0;
memset(disk_super->uuid, 0, sizeof(disk_super->uuid));
disk_super->magic = cpu_to_le64(CACHE_SUPERBLOCK_MAGIC);
- disk_super->version = cpu_to_le32(MAX_CACHE_VERSION);
+ disk_super->version = cpu_to_le32(cmd->version);
memset(disk_super->policy_name, 0, sizeof(disk_super->policy_name));
memset(disk_super->policy_version, 0, sizeof(disk_super->policy_version));
disk_super->policy_hint_size = 0;
@@ -362,6 +382,9 @@ static int __write_initial_superblock(struct dm_cache_metadata *cmd)
disk_super->write_hits = cpu_to_le32(0);
disk_super->write_misses = cpu_to_le32(0);
+ if (separate_dirty_bits(cmd))
+ disk_super->dirty_root = cpu_to_le64(cmd->dirty_root);
+
return dm_tm_commit(cmd->tm, sblock);
}
@@ -382,6 +405,13 @@ static int __format_metadata(struct dm_cache_metadata *cmd)
if (r < 0)
goto bad;
+ if (separate_dirty_bits(cmd)) {
+ dm_disk_bitset_init(cmd->tm, &cmd->dirty_info);
+ r = dm_bitset_empty(&cmd->dirty_info, &cmd->dirty_root);
+ if (r < 0)
+ goto bad;
+ }
+
dm_disk_bitset_init(cmd->tm, &cmd->discard_info);
r = dm_bitset_empty(&cmd->discard_info, &cmd->discard_root);
if (r < 0)
@@ -407,9 +437,10 @@ bad:
static int __check_incompat_features(struct cache_disk_superblock *disk_super,
struct dm_cache_metadata *cmd)
{
- uint32_t features;
+ uint32_t incompat_flags, features;
- features = le32_to_cpu(disk_super->incompat_flags) & ~DM_CACHE_FEATURE_INCOMPAT_SUPP;
+ incompat_flags = le32_to_cpu(disk_super->incompat_flags);
+ features = incompat_flags & ~DM_CACHE_FEATURE_INCOMPAT_SUPP;
if (features) {
DMERR("could not access metadata due to unsupported optional features (%lx).",
(unsigned long)features);
@@ -470,6 +501,7 @@ static int __open_metadata(struct dm_cache_metadata *cmd)
}
__setup_mapping_info(cmd);
+ dm_disk_bitset_init(cmd->tm, &cmd->dirty_info);
dm_disk_bitset_init(cmd->tm, &cmd->discard_info);
sb_flags = le32_to_cpu(disk_super->flags);
cmd->clean_when_opened = test_bit(CLEAN_SHUTDOWN, &sb_flags);
@@ -548,6 +580,7 @@ static unsigned long clear_clean_shutdown(unsigned long flags)
static void read_superblock_fields(struct dm_cache_metadata *cmd,
struct cache_disk_superblock *disk_super)
{
+ cmd->version = le32_to_cpu(disk_super->version);
cmd->flags = le32_to_cpu(disk_super->flags);
cmd->root = le64_to_cpu(disk_super->mapping_root);
cmd->hint_root = le64_to_cpu(disk_super->hint_root);
@@ -567,6 +600,9 @@ static void read_superblock_fields(struct dm_cache_metadata *cmd,
cmd->stats.write_hits = le32_to_cpu(disk_super->write_hits);
cmd->stats.write_misses = le32_to_cpu(disk_super->write_misses);
+ if (separate_dirty_bits(cmd))
+ cmd->dirty_root = le64_to_cpu(disk_super->dirty_root);
+
cmd->changed = false;
}
@@ -625,6 +661,13 @@ static int __commit_transaction(struct dm_cache_metadata *cmd,
*/
BUILD_BUG_ON(sizeof(struct cache_disk_superblock) > 512);
+ if (separate_dirty_bits(cmd)) {
+ r = dm_bitset_flush(&cmd->dirty_info, cmd->dirty_root,
+ &cmd->dirty_root);
+ if (r)
+ return r;
+ }
+
r = dm_bitset_flush(&cmd->discard_info, cmd->discard_root,
&cmd->discard_root);
if (r)
@@ -649,6 +692,8 @@ static int __commit_transaction(struct dm_cache_metadata *cmd,
update_flags(disk_super, mutator);
disk_super->mapping_root = cpu_to_le64(cmd->root);
+ if (separate_dirty_bits(cmd))
+ disk_super->dirty_root = cpu_to_le64(cmd->dirty_root);
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);
@@ -698,7 +743,8 @@ static void unpack_value(__le64 value_le, dm_oblock_t *block, unsigned *flags)
static struct dm_cache_metadata *metadata_open(struct block_device *bdev,
sector_t data_block_size,
bool may_format_device,
- size_t policy_hint_size)
+ size_t policy_hint_size,
+ unsigned metadata_version)
{
int r;
struct dm_cache_metadata *cmd;
@@ -709,6 +755,7 @@ static struct dm_cache_metadata *metadata_open(struct block_device *bdev,
return ERR_PTR(-ENOMEM);
}
+ cmd->version = metadata_version;
atomic_set(&cmd->ref_count, 1);
init_rwsem(&cmd->root_lock);
cmd->bdev = bdev;
@@ -757,7 +804,8 @@ static struct dm_cache_metadata *lookup(struct block_device *bdev)
static struct dm_cache_metadata *lookup_or_open(struct block_device *bdev,
sector_t data_block_size,
bool may_format_device,
- size_t policy_hint_size)
+ size_t policy_hint_size,
+ unsigned metadata_version)
{
struct dm_cache_metadata *cmd, *cmd2;
@@ -768,7 +816,8 @@ static struct dm_cache_metadata *lookup_or_open(struct block_device *bdev,
if (cmd)
return cmd;
- cmd = metadata_open(bdev, data_block_size, may_format_device, policy_hint_size);
+ cmd = metadata_open(bdev, data_block_size, may_format_device,
+ policy_hint_size, metadata_version);
if (!IS_ERR(cmd)) {
mutex_lock(&table_lock);
cmd2 = lookup(bdev);
@@ -800,10 +849,11 @@ static bool same_params(struct dm_cache_metadata *cmd, sector_t data_block_size)
struct dm_cache_metadata *dm_cache_metadata_open(struct block_device *bdev,
sector_t data_block_size,
bool may_format_device,
- size_t policy_hint_size)
+ size_t policy_hint_size,
+ unsigned metadata_version)
{
- struct dm_cache_metadata *cmd = lookup_or_open(bdev, data_block_size,
- may_format_device, policy_hint_size);
+ struct dm_cache_metadata *cmd = lookup_or_open(bdev, data_block_size, may_format_device,
+ policy_hint_size, metadata_version);
if (!IS_ERR(cmd) && !same_params(cmd, data_block_size)) {
dm_cache_metadata_close(cmd);
@@ -829,8 +879,8 @@ void dm_cache_metadata_close(struct dm_cache_metadata *cmd)
/*
* Checks that the given cache block is either unmapped or clean.
*/
-static int block_unmapped_or_clean(struct dm_cache_metadata *cmd, dm_cblock_t b,
- bool *result)
+static int block_clean_combined_dirty(struct dm_cache_metadata *cmd, dm_cblock_t b,
+ bool *result)
{
int r;
__le64 value;
@@ -838,10 +888,8 @@ static int block_unmapped_or_clean(struct dm_cache_metadata *cmd, dm_cblock_t b,
unsigned flags;
r = dm_array_get_value(&cmd->info, cmd->root, from_cblock(b), &value);
- if (r) {
- DMERR("block_unmapped_or_clean failed");
+ if (r)
return r;
- }
unpack_value(value, &ob, &flags);
*result = !((flags & M_VALID) && (flags & M_DIRTY));
@@ -849,17 +897,19 @@ static int block_unmapped_or_clean(struct dm_cache_metadata *cmd, dm_cblock_t b,
return 0;
}
-static int blocks_are_unmapped_or_clean(struct dm_cache_metadata *cmd,
- dm_cblock_t begin, dm_cblock_t end,
- bool *result)
+static int blocks_are_clean_combined_dirty(struct dm_cache_metadata *cmd,
+ dm_cblock_t begin, dm_cblock_t end,
+ bool *result)
{
int r;
*result = true;
while (begin != end) {
- r = block_unmapped_or_clean(cmd, begin, result);
- if (r)
+ r = block_clean_combined_dirty(cmd, begin, result);
+ if (r) {
+ DMERR("block_clean_combined_dirty failed");
return r;
+ }
if (!*result) {
DMERR("cache block %llu is dirty",
@@ -873,6 +923,48 @@ static int blocks_are_unmapped_or_clean(struct dm_cache_metadata *cmd,
return 0;
}
+static int blocks_are_clean_separate_dirty(struct dm_cache_metadata *cmd,
+ dm_cblock_t begin, dm_cblock_t end,
+ bool *result)
+{
+ int r;
+ bool dirty_flag;
+ *result = true;
+
+ // FIXME: use a cursor so we can benefit from preloading metadata.
+ while (begin != end) {
+ /*
+ * We assume that unmapped blocks have their dirty bit
+ * cleared.
+ */
+ r = dm_bitset_test_bit(&cmd->dirty_info, cmd->dirty_root,
+ from_cblock(begin), &cmd->dirty_root, &dirty_flag);
+ if (r)
+ return r;
+
+ if (dirty_flag) {
+ DMERR("cache block %llu is dirty",
+ (unsigned long long) from_cblock(begin));
+ *result = false;
+ return 0;
+ }
+
+ begin = to_cblock(from_cblock(begin) + 1);
+ }
+
+ return 0;
+}
+
+static int blocks_are_unmapped_or_clean(struct dm_cache_metadata *cmd,
+ dm_cblock_t begin, dm_cblock_t end,
+ bool *result)
+{
+ if (separate_dirty_bits(cmd))
+ return blocks_are_clean_separate_dirty(cmd, begin, end, result);
+ else
+ return blocks_are_clean_combined_dirty(cmd, begin, end, result);
+}
+
static bool cmd_write_lock(struct dm_cache_metadata *cmd)
{
down_write(&cmd->root_lock);
@@ -950,8 +1042,18 @@ int dm_cache_resize(struct dm_cache_metadata *cmd, dm_cblock_t new_cache_size)
r = dm_array_resize(&cmd->info, cmd->root, from_cblock(cmd->cache_blocks),
from_cblock(new_cache_size),
&null_mapping, &cmd->root);
- if (!r)
- cmd->cache_blocks = new_cache_size;
+ if (r)
+ goto out;
+
+ if (separate_dirty_bits(cmd)) {
+ r = dm_bitset_resize(&cmd->dirty_info, cmd->dirty_root,
+ from_cblock(cmd->cache_blocks), from_cblock(new_cache_size),
+ false, &cmd->dirty_root);
+ if (r)
+ goto out;
+ }
+
+ cmd->cache_blocks = new_cache_size;
cmd->changed = true;
out:
@@ -1185,11 +1287,11 @@ static bool hints_array_available(struct dm_cache_metadata *cmd,
hints_array_initialized(cmd);
}
-static int __load_mapping(struct dm_cache_metadata *cmd,
- uint64_t cb, bool hints_valid,
- struct dm_array_cursor *mapping_cursor,
- struct dm_array_cursor *hint_cursor,
- load_mapping_fn fn, void *context)
+static int __load_mapping_v1(struct dm_cache_metadata *cmd,
+ uint64_t cb, bool hints_valid,
+ struct dm_array_cursor *mapping_cursor,
+ struct dm_array_cursor *hint_cursor,
+ load_mapping_fn fn, void *context)
{
int r = 0;
@@ -1221,6 +1323,45 @@ static int __load_mapping(struct dm_cache_metadata *cmd,
return r;
}
+static int __load_mapping_v2(struct dm_cache_metadata *cmd,
+ uint64_t cb, bool hints_valid,
+ struct dm_array_cursor *mapping_cursor,
+ struct dm_array_cursor *hint_cursor,
+ struct dm_bitset_cursor *dirty_cursor,
+ load_mapping_fn fn, void *context)
+{
+ int r = 0;
+
+ __le64 mapping;
+ __le32 hint = 0;
+
+ __le64 *mapping_value_le;
+ __le32 *hint_value_le;
+
+ dm_oblock_t oblock;
+ unsigned flags;
+ bool dirty;
+
+ dm_array_cursor_get_value(mapping_cursor, (void **) &mapping_value_le);
+ memcpy(&mapping, mapping_value_le, sizeof(mapping));
+ unpack_value(mapping, &oblock, &flags);
+
+ if (flags & M_VALID) {
+ if (hints_valid) {
+ dm_array_cursor_get_value(hint_cursor, (void **) &hint_value_le);
+ memcpy(&hint, hint_value_le, sizeof(hint));
+ }
+
+ dirty = dm_bitset_cursor_get_value(dirty_cursor);
+ r = fn(context, oblock, to_cblock(cb), dirty,
+ le32_to_cpu(hint), hints_valid);
+ if (r)
+ DMERR("policy couldn't load cblock");
+ }
+
+ return r;
+}
+
static int __load_mappings(struct dm_cache_metadata *cmd,
struct dm_cache_policy *policy,
load_mapping_fn fn, void *context)
@@ -1246,10 +1387,28 @@ static int __load_mappings(struct dm_cache_metadata *cmd,
}
}
+ if (separate_dirty_bits(cmd)) {
+ r = dm_bitset_cursor_begin(&cmd->dirty_info, cmd->dirty_root,
+ from_cblock(cmd->cache_blocks),
+ &cmd->dirty_cursor);
+ if (r) {
+ dm_array_cursor_end(&cmd->hint_cursor);
+ dm_array_cursor_end(&cmd->mapping_cursor);
+ return r;
+ }
+ }
+
for (cb = 0; ; cb++) {
- r = __load_mapping(cmd, cb, hints_valid,
- &cmd->mapping_cursor, &cmd->hint_cursor,
- fn, context);
+ if (separate_dirty_bits(cmd))
+ r = __load_mapping_v2(cmd, cb, hints_valid,
+ &cmd->mapping_cursor,
+ &cmd->hint_cursor,
+ &cmd->dirty_cursor,
+ fn, context);
+ else
+ r = __load_mapping_v1(cmd, cb, hints_valid,
+ &cmd->mapping_cursor, &cmd->hint_cursor,
+ fn, context);
if (r)
goto out;
@@ -1272,12 +1431,23 @@ static int __load_mappings(struct dm_cache_metadata *cmd,
goto out;
}
}
+
+ if (separate_dirty_bits(cmd)) {
+ r = dm_bitset_cursor_next(&cmd->dirty_cursor);
+ if (r) {
+ DMERR("dm_bitset_cursor_next for dirty failed");
+ goto out;
+ }
+ }
}
out:
dm_array_cursor_end(&cmd->mapping_cursor);
if (hints_valid)
dm_array_cursor_end(&cmd->hint_cursor);
+ if (separate_dirty_bits(cmd))
+ dm_bitset_cursor_end(&cmd->dirty_cursor);
+
return r;
}
@@ -1360,13 +1530,55 @@ static int __dirty(struct dm_cache_metadata *cmd, dm_cblock_t cblock, bool dirty
}
-int dm_cache_set_dirty(struct dm_cache_metadata *cmd,
- dm_cblock_t cblock, bool dirty)
+static int __set_dirty_bits_v1(struct dm_cache_metadata *cmd, unsigned nr_bits, unsigned long *bits)
+{
+ int r;
+ unsigned i;
+ for (i = 0; i < nr_bits; i++) {
+ r = __dirty(cmd, to_cblock(i), test_bit(i, bits));
+ if (r)
+ return r;
+ }
+
+ return 0;
+}
+
+static int __set_dirty_bits_v2(struct dm_cache_metadata *cmd, unsigned nr_bits, unsigned long *bits)
+{
+ int r = 0;
+ unsigned i;
+
+ /* nr_bits is really just a sanity check */
+ if (nr_bits != from_cblock(cmd->cache_blocks)) {
+ DMERR("dirty bitset is wrong size");
+ return -EINVAL;
+ }
+
+ for (i = 0; i < nr_bits; i++) {
+ if (test_bit(i, bits))
+ r = dm_bitset_set_bit(&cmd->dirty_info, cmd->dirty_root, i, &cmd->dirty_root);
+ else
+ r = dm_bitset_clear_bit(&cmd->dirty_info, cmd->dirty_root, i, &cmd->dirty_root);
+
+ if (r)
+ return r;
+ }
+
+ cmd->changed = true;
+ return dm_bitset_flush(&cmd->dirty_info, cmd->dirty_root, &cmd->dirty_root);
+}
+
+int dm_cache_set_dirty_bits(struct dm_cache_metadata *cmd,
+ unsigned nr_bits,
+ unsigned long *bits)
{
int r;
WRITE_LOCK(cmd);
- r = __dirty(cmd, cblock, dirty);
+ if (separate_dirty_bits(cmd))
+ r = __set_dirty_bits_v2(cmd, nr_bits, bits);
+ else
+ r = __set_dirty_bits_v1(cmd, nr_bits, bits);
WRITE_UNLOCK(cmd);
return r;