--- /dev/null
+Introduction
+============
+
+dm-era is a target that behaves similar to the linear target. In
+addition it keeps track of which blocks were written within a user
+defined period of time called an 'era'. Each era target instance
+maintains the current era as a monotonically increasing 32-bit
+counter.
+
+Use cases include tracking changed blocks for backup software, and
+partially invalidating the contents of a cache to restore cache
+coherency after rolling back a vendor snapshot.
+
+Constructor
+===========
+
+ era <metadata dev> <origin dev> <block size>
+
+ metadata dev : fast device holding the persistent metadata
+ origin dev : device holding data blocks that may change
+ block size : block size of origin data device, granularity that is
+ tracked by the target
+
+Messages
+========
+
+None of the dm messages take any arguments.
+
+checkpoint
+----------
+
+Possibly move to a new era. You shouldn't assume the era has
+incremented. After sending this message, you should check the
+current era via the status line.
+
+take_metadata_snap
+------------------
+
+Create a clone of the metadata, to allow a userland process to read it.
+
+drop_metadata_snap
+------------------
+
+Drop the metadata snapshot.
+
+Status
+======
+
+<metadata block size> <#used metadata blocks>/<#total metadata blocks>
+<current era> <held metadata root | '-'>
+
+metadata block size : Fixed block size for each metadata block in
+ sectors
+#used metadata blocks : Number of metadata blocks used
+#total metadata blocks : Total number of metadata blocks
+current era : The current era
+held metadata root : The location, in blocks, of the metadata root
+ that has been 'held' for userspace read
+ access. '-' indicates there is no held root
+
+Detailed use case
+=================
+
+The scenario of invalidating a cache when rolling back a vendor
+snapshot was the primary use case when developing this target:
+
+Taking a vendor snapshot
+------------------------
+
+- Send a checkpoint message to the era target
+- Make a note of the current era in its status line
+- Take vendor snapshot (the era and snapshot should be forever
+ associated now).
+
+Rolling back to an vendor snapshot
+----------------------------------
+
+- Cache enters passthrough mode (see: dm-cache's docs in cache.txt)
+- Rollback vendor storage
+- Take metadata snapshot
+- Ascertain which blocks have been written since the snapshot was taken
+ by checking each block's era
+- Invalidate those blocks in the caching software
+- Cache returns to writeback/writethrough mode
+
+Memory usage
+============
+
+The target uses a bitset to record writes in the current era. It also
+has a spare bitset ready for switching over to a new era. Other than
+that it uses a few 4k blocks for updating metadata.
+
+ (4 * nr_blocks) bytes + buffers
+
+Resilience
+==========
+
+Metadata is updated on disk before a write to a previously unwritten
+block is performed. As such dm-era should not be effected by a hard
+crash such as power failure.
+
+Userland tools
+==============
+
+Userland tools are found in the increasingly poorly named
+thin-provisioning-tools project:
+
+ https://github.com/jthornber/thin-provisioning-tools
A simple cache policy that writes back all data to the
origin. Used when decommissioning a dm-cache.
+config DM_ERA
+ tristate "Era target (EXPERIMENTAL)"
+ depends on BLK_DEV_DM
+ default n
+ select DM_PERSISTENT_DATA
+ select DM_BIO_PRISON
+ ---help---
+ dm-era tracks which parts of a block device are written to
+ over time. Useful for maintaining cache coherency when using
+ vendor snapshots.
+
config DM_MIRROR
tristate "Mirror target"
depends on BLK_DEV_DM
dm-cache-y += dm-cache-target.o dm-cache-metadata.o dm-cache-policy.o
dm-cache-mq-y += dm-cache-policy-mq.o
dm-cache-cleaner-y += dm-cache-policy-cleaner.o
+dm-era-y += dm-era-target.o
md-mod-y += md.o bitmap.o
raid456-y += raid5.o
obj-$(CONFIG_DM_CACHE) += dm-cache.o
obj-$(CONFIG_DM_CACHE_MQ) += dm-cache-mq.o
obj-$(CONFIG_DM_CACHE_CLEANER) += dm-cache-cleaner.o
+obj-$(CONFIG_DM_ERA) += dm-era.o
ifeq ($(CONFIG_DM_UEVENT),y)
dm-mod-objs += dm-uevent.o
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)
{
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 */
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;
unsigned policy_version[CACHE_POLICY_VERSION_SIZE];
size_t policy_hint_size;
struct dm_cache_statistics stats;
+
+ /*
+ * Reading the space map root can fail, so we read it into this
+ * buffer before the superblock is locked and updated.
+ */
+ __u8 metadata_space_map_root[SPACE_MAP_ROOT_SIZE];
};
/*-------------------------------------------------------------------
}
}
+static int __save_sm_root(struct dm_cache_metadata *cmd)
+{
+ int r;
+ size_t metadata_len;
+
+ r = dm_sm_root_size(cmd->metadata_sm, &metadata_len);
+ if (r < 0)
+ return r;
+
+ return dm_sm_copy_root(cmd->metadata_sm, &cmd->metadata_space_map_root,
+ metadata_len);
+}
+
+static void __copy_sm_root(struct dm_cache_metadata *cmd,
+ struct cache_disk_superblock *disk_super)
+{
+ memcpy(&disk_super->metadata_space_map_root,
+ &cmd->metadata_space_map_root,
+ sizeof(cmd->metadata_space_map_root));
+}
+
static int __write_initial_superblock(struct dm_cache_metadata *cmd)
{
int r;
struct dm_block *sblock;
- size_t metadata_len;
struct cache_disk_superblock *disk_super;
sector_t bdev_size = i_size_read(cmd->bdev->bd_inode) >> SECTOR_SHIFT;
if (bdev_size > DM_CACHE_METADATA_MAX_SECTORS)
bdev_size = DM_CACHE_METADATA_MAX_SECTORS;
- r = dm_sm_root_size(cmd->metadata_sm, &metadata_len);
+ r = dm_tm_pre_commit(cmd->tm);
if (r < 0)
return r;
- r = dm_tm_pre_commit(cmd->tm);
- if (r < 0)
+ /*
+ * dm_sm_copy_root() can fail. So we need to do it before we start
+ * updating the superblock.
+ */
+ r = __save_sm_root(cmd);
+ if (r)
return r;
r = superblock_lock_zero(cmd, &sblock);
memset(disk_super->policy_version, 0, sizeof(disk_super->policy_version));
disk_super->policy_hint_size = 0;
- r = dm_sm_copy_root(cmd->metadata_sm, &disk_super->metadata_space_map_root,
- metadata_len);
- if (r < 0)
- goto bad_locked;
+ __copy_sm_root(cmd, disk_super);
disk_super->mapping_root = cpu_to_le64(cmd->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);
- 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);
disk_super->write_misses = cpu_to_le32(0);
return dm_tm_commit(cmd->tm, sblock);
-
-bad_locked:
- dm_bm_unlock(sblock);
- return r;
}
static int __format_metadata(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));
disk_super = dm_block_data(sblock);
update_flags(disk_super, mutator);
read_superblock_fields(cmd, disk_super);
+ dm_bm_unlock(sblock);
- return dm_bm_flush_and_unlock(cmd->bm, sblock);
+ return dm_bm_flush(cmd->bm);
}
static int __begin_transaction(struct dm_cache_metadata *cmd)
flags_mutator mutator)
{
int r;
- size_t metadata_len;
struct cache_disk_superblock *disk_super;
struct dm_block *sblock;
if (r < 0)
return r;
- r = dm_sm_root_size(cmd->metadata_sm, &metadata_len);
- if (r < 0)
+ r = __save_sm_root(cmd);
+ if (r)
return r;
r = superblock_lock(cmd, &sblock);
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]);
disk_super->read_misses = cpu_to_le32(cmd->stats.read_misses);
disk_super->write_hits = cpu_to_le32(cmd->stats.write_hits);
disk_super->write_misses = cpu_to_le32(cmd->stats.write_misses);
-
- r = dm_sm_copy_root(cmd->metadata_sm, &disk_super->metadata_space_map_root,
- metadata_len);
- if (r < 0) {
- dm_bm_unlock(sblock);
- return r;
- }
+ __copy_sm_root(cmd, disk_super);
return dm_tm_commit(cmd->tm, sblock);
}
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;
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;
}
int dm_cache_set_discard(struct dm_cache_metadata *cmd,
- dm_dblock_t dblock, bool discard)
+ dm_oblock_t dblock, bool discard)
{
int r;
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);
return 0;
}
-int dm_cache_begin_hints(struct dm_cache_metadata *cmd, struct dm_cache_policy *policy)
+static int save_hint(void *context, dm_cblock_t cblock, dm_oblock_t oblock, uint32_t hint)
{
+ struct dm_cache_metadata *cmd = context;
+ __le32 value = cpu_to_le32(hint);
int r;
- down_write(&cmd->root_lock);
- r = begin_hints(cmd, policy);
- up_write(&cmd->root_lock);
-
- return r;
-}
-
-static int save_hint(struct dm_cache_metadata *cmd, dm_cblock_t cblock,
- uint32_t hint)
-{
- int r;
- __le32 value = cpu_to_le32(hint);
__dm_bless_for_disk(&value);
r = dm_array_set_value(&cmd->hint_info, cmd->hint_root,
return r;
}
-int dm_cache_save_hint(struct dm_cache_metadata *cmd, dm_cblock_t cblock,
- uint32_t hint)
+static int write_hints(struct dm_cache_metadata *cmd, struct dm_cache_policy *policy)
{
int r;
- if (!hints_array_initialized(cmd))
- return 0;
+ r = begin_hints(cmd, policy);
+ if (r) {
+ DMERR("begin_hints failed");
+ return r;
+ }
+
+ return policy_walk_mappings(policy, save_hint, cmd);
+}
+
+int dm_cache_write_hints(struct dm_cache_metadata *cmd, struct dm_cache_policy *policy)
+{
+ int r;
down_write(&cmd->root_lock);
- r = save_hint(cmd, cblock, hint);
+ r = write_hints(cmd, policy);
up_write(&cmd->root_lock);
return r;
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);
* rather than querying the policy for each cblock, we let it walk its data
* structures and fill in the hints in whatever order it wishes.
*/
-
-int dm_cache_begin_hints(struct dm_cache_metadata *cmd, struct dm_cache_policy *p);
-
-/*
- * requests hints for every cblock and stores in the metadata device.
- */
-int dm_cache_save_hint(struct dm_cache_metadata *cmd,
- dm_cblock_t cblock, uint32_t hint);
+int dm_cache_write_hints(struct dm_cache_metadata *cmd, struct dm_cache_policy *p);
/*
* Query method. Are all the blocks in the cache clean?
/*
* 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; /* a power of 2 times sectors per block */
/*
* Rather than reconstructing the table line for the status we just
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;
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;
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,
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);
}
}
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);
}
return 0;
}
-/*
- * We want the discard block size to be a power of two, at least the size
- * of the cache block size, and have no more than 2^14 discard blocks
- * across the origin.
- */
-#define MAX_DISCARD_BLOCKS (1 << 14)
-
-static bool too_many_discard_blocks(sector_t discard_block_size,
- sector_t origin_size)
-{
- (void) sector_div(origin_size, discard_block_size);
-
- return origin_size > MAX_DISCARD_BLOCKS;
-}
-
-static sector_t calculate_discard_block_size(sector_t cache_block_size,
- sector_t origin_size)
-{
- sector_t discard_block_size;
-
- discard_block_size = roundup_pow_of_two(cache_block_size);
-
- if (origin_size)
- while (too_many_discard_blocks(discard_block_size, origin_size))
- discard_block_size *= 2;
-
- return discard_block_size;
-}
-
#define DEFAULT_MIGRATION_THRESHOLD 2048
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 =
- calculate_discard_block_size(cache->sectors_per_block,
- cache->origin_sectors);
- 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)) {
{
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;
}
return 0;
}
-static int save_hint(void *context, dm_cblock_t cblock, dm_oblock_t oblock,
- uint32_t hint)
-{
- struct cache *cache = context;
- return dm_cache_save_hint(cache->cmd, cblock, hint);
-}
-
-static int write_hints(struct cache *cache)
-{
- int r;
-
- r = dm_cache_begin_hints(cache->cmd, cache->policy);
- if (r) {
- DMERR("dm_cache_begin_hints failed");
- return r;
- }
-
- r = policy_walk_mappings(cache->policy, save_hint, cache);
- if (r)
- DMERR("policy_walk_mappings failed");
-
- return r;
-}
-
/*
* returns true on success
*/
save_stats(cache);
- r3 = write_hints(cache);
+ r3 = dm_cache_write_hints(cache->cmd, cache->policy);
if (r3)
DMERR("could not write hints");
}
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;
}
/*
* FIXME: these limits may be incompatible with the cache device
*/
- limits->max_discard_sectors = cache->discard_block_size * 1024;
- 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)
static struct target_type cache_target = {
.name = "cache",
- .version = {1, 3, 0},
+ .version = {1, 4, 0},
.module = THIS_MODULE,
.ctr = cache_ctr,
.dtr = cache_dtr,
--- /dev/null
+#include "dm.h"
+#include "persistent-data/dm-transaction-manager.h"
+#include "persistent-data/dm-bitset.h"
+#include "persistent-data/dm-space-map.h"
+
+#include <linux/dm-io.h>
+#include <linux/dm-kcopyd.h>
+#include <linux/init.h>
+#include <linux/mempool.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/vmalloc.h>
+
+#define DM_MSG_PREFIX "era"
+
+#define SUPERBLOCK_LOCATION 0
+#define SUPERBLOCK_MAGIC 2126579579
+#define SUPERBLOCK_CSUM_XOR 146538381
+#define MIN_ERA_VERSION 1
+#define MAX_ERA_VERSION 1
+#define INVALID_WRITESET_ROOT SUPERBLOCK_LOCATION
+#define MIN_BLOCK_SIZE 8
+
+/*----------------------------------------------------------------
+ * Writeset
+ *--------------------------------------------------------------*/
+struct writeset_metadata {
+ uint32_t nr_bits;
+ dm_block_t root;
+};
+
+struct writeset {
+ struct writeset_metadata md;
+
+ /*
+ * An in core copy of the bits to save constantly doing look ups on
+ * disk.
+ */
+ unsigned long *bits;
+};
+
+/*
+ * This does not free off the on disk bitset as this will normally be done
+ * after digesting into the era array.
+ */
+static void writeset_free(struct writeset *ws)
+{
+ vfree(ws->bits);
+}
+
+static int setup_on_disk_bitset(struct dm_disk_bitset *info,
+ unsigned nr_bits, dm_block_t *root)
+{
+ int r;
+
+ r = dm_bitset_empty(info, root);
+ if (r)
+ return r;
+
+ return dm_bitset_resize(info, *root, 0, nr_bits, false, root);
+}
+
+static size_t bitset_size(unsigned nr_bits)
+{
+ return sizeof(unsigned long) * dm_div_up(nr_bits, BITS_PER_LONG);
+}
+
+/*
+ * Allocates memory for the in core bitset.
+ */
+static int writeset_alloc(struct writeset *ws, dm_block_t nr_blocks)
+{
+ ws->md.nr_bits = nr_blocks;
+ ws->md.root = INVALID_WRITESET_ROOT;
+ ws->bits = vzalloc(bitset_size(nr_blocks));
+ if (!ws->bits) {
+ DMERR("%s: couldn't allocate in memory bitset", __func__);
+ return -ENOMEM;
+ }
+
+ return 0;
+}
+
+/*
+ * Wipes the in-core bitset, and creates a new on disk bitset.
+ */
+static int writeset_init(struct dm_disk_bitset *info, struct writeset *ws)
+{
+ int r;
+
+ memset(ws->bits, 0, bitset_size(ws->md.nr_bits));
+
+ r = setup_on_disk_bitset(info, ws->md.nr_bits, &ws->md.root);
+ if (r) {
+ DMERR("%s: setup_on_disk_bitset failed", __func__);
+ return r;
+ }
+
+ return 0;
+}
+
+static bool writeset_marked(struct writeset *ws, dm_block_t block)
+{
+ return test_bit(block, ws->bits);
+}
+
+static int writeset_marked_on_disk(struct dm_disk_bitset *info,
+ struct writeset_metadata *m, dm_block_t block,
+ bool *result)
+{
+ dm_block_t old = m->root;
+
+ /*
+ * The bitset was flushed when it was archived, so we know there'll
+ * be no change to the root.
+ */
+ int r = dm_bitset_test_bit(info, m->root, block, &m->root, result);
+ if (r) {
+ DMERR("%s: dm_bitset_test_bit failed", __func__);
+ return r;
+ }
+
+ BUG_ON(m->root != old);
+
+ return r;
+}
+
+/*
+ * Returns < 0 on error, 0 if the bit wasn't previously set, 1 if it was.
+ */
+static int writeset_test_and_set(struct dm_disk_bitset *info,
+ struct writeset *ws, uint32_t block)
+{
+ int r;
+
+ if (!test_and_set_bit(block, ws->bits)) {
+ r = dm_bitset_set_bit(info, ws->md.root, block, &ws->md.root);
+ if (r) {
+ /* FIXME: fail mode */
+ return r;
+ }
+
+ return 0;
+ }
+
+ return 1;
+}
+
+/*----------------------------------------------------------------
+ * On disk metadata layout
+ *--------------------------------------------------------------*/
+#define SPACE_MAP_ROOT_SIZE 128
+#define UUID_LEN 16
+
+struct writeset_disk {
+ __le32 nr_bits;
+ __le64 root;
+} __packed;
+
+struct superblock_disk {
+ __le32 csum;
+ __le32 flags;
+ __le64 blocknr;
+
+ __u8 uuid[UUID_LEN];
+ __le64 magic;
+ __le32 version;
+
+ __u8 metadata_space_map_root[SPACE_MAP_ROOT_SIZE];
+
+ __le32 data_block_size;
+ __le32 metadata_block_size;
+ __le32 nr_blocks;
+
+ __le32 current_era;
+ struct writeset_disk current_writeset;
+
+ /*
+ * Only these two fields are valid within the metadata snapshot.
+ */
+ __le64 writeset_tree_root;
+ __le64 era_array_root;
+
+ __le64 metadata_snap;
+} __packed;
+
+/*----------------------------------------------------------------
+ * Superblock validation
+ *--------------------------------------------------------------*/
+static void sb_prepare_for_write(struct dm_block_validator *v,
+ struct dm_block *b,
+ size_t sb_block_size)
+{
+ struct superblock_disk *disk = dm_block_data(b);
+
+ disk->blocknr = cpu_to_le64(dm_block_location(b));
+ disk->csum = cpu_to_le32(dm_bm_checksum(&disk->flags,
+ sb_block_size - sizeof(__le32),
+ SUPERBLOCK_CSUM_XOR));
+}
+
+static int check_metadata_version(struct superblock_disk *disk)
+{
+ uint32_t metadata_version = le32_to_cpu(disk->version);
+ if (metadata_version < MIN_ERA_VERSION || metadata_version > MAX_ERA_VERSION) {
+ DMERR("Era metadata version %u found, but only versions between %u and %u supported.",
+ metadata_version, MIN_ERA_VERSION, MAX_ERA_VERSION);
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+static int sb_check(struct dm_block_validator *v,
+ struct dm_block *b,
+ size_t sb_block_size)
+{
+ struct superblock_disk *disk = dm_block_data(b);
+ __le32 csum_le;
+
+ if (dm_block_location(b) != le64_to_cpu(disk->blocknr)) {
+ DMERR("sb_check failed: blocknr %llu: wanted %llu",
+ le64_to_cpu(disk->blocknr),
+ (unsigned long long)dm_block_location(b));
+ return -ENOTBLK;
+ }
+
+ if (le64_to_cpu(disk->magic) != SUPERBLOCK_MAGIC) {
+ DMERR("sb_check failed: magic %llu: wanted %llu",
+ le64_to_cpu(disk->magic),
+ (unsigned long long) SUPERBLOCK_MAGIC);
+ return -EILSEQ;
+ }
+
+ csum_le = cpu_to_le32(dm_bm_checksum(&disk->flags,
+ sb_block_size - sizeof(__le32),
+ SUPERBLOCK_CSUM_XOR));
+ if (csum_le != disk->csum) {
+ DMERR("sb_check failed: csum %u: wanted %u",
+ le32_to_cpu(csum_le), le32_to_cpu(disk->csum));
+ return -EILSEQ;
+ }
+
+ return check_metadata_version(disk);
+}
+
+static struct dm_block_validator sb_validator = {
+ .name = "superblock",
+ .prepare_for_write = sb_prepare_for_write,
+ .check = sb_check
+};
+
+/*----------------------------------------------------------------
+ * Low level metadata handling
+ *--------------------------------------------------------------*/
+#define DM_ERA_METADATA_BLOCK_SIZE 4096
+#define DM_ERA_METADATA_CACHE_SIZE 64
+#define ERA_MAX_CONCURRENT_LOCKS 5
+
+struct era_metadata {
+ struct block_device *bdev;
+ struct dm_block_manager *bm;
+ struct dm_space_map *sm;
+ struct dm_transaction_manager *tm;
+
+ dm_block_t block_size;
+ uint32_t nr_blocks;
+
+ uint32_t current_era;
+
+ /*
+ * We preallocate 2 writesets. When an era rolls over we
+ * switch between them. This means the allocation is done at
+ * preresume time, rather than on the io path.
+ */
+ struct writeset writesets[2];
+ struct writeset *current_writeset;
+
+ dm_block_t writeset_tree_root;
+ dm_block_t era_array_root;
+
+ struct dm_disk_bitset bitset_info;
+ struct dm_btree_info writeset_tree_info;
+ struct dm_array_info era_array_info;
+
+ dm_block_t metadata_snap;
+
+ /*
+ * A flag that is set whenever a writeset has been archived.
+ */
+ bool archived_writesets;
+
+ /*
+ * Reading the space map root can fail, so we read it into this
+ * buffer before the superblock is locked and updated.
+ */
+ __u8 metadata_space_map_root[SPACE_MAP_ROOT_SIZE];
+};
+
+static int superblock_read_lock(struct era_metadata *md,
+ struct dm_block **sblock)
+{
+ return dm_bm_read_lock(md->bm, SUPERBLOCK_LOCATION,
+ &sb_validator, sblock);
+}
+
+static int superblock_lock_zero(struct era_metadata *md,
+ struct dm_block **sblock)
+{
+ return dm_bm_write_lock_zero(md->bm, SUPERBLOCK_LOCATION,
+ &sb_validator, sblock);
+}
+
+static int superblock_lock(struct era_metadata *md,
+ struct dm_block **sblock)
+{
+ return dm_bm_write_lock(md->bm, SUPERBLOCK_LOCATION,
+ &sb_validator, sblock);
+}
+
+/* FIXME: duplication with cache and thin */
+static int superblock_all_zeroes(struct dm_block_manager *bm, bool *result)
+{
+ int r;
+ unsigned i;
+ struct dm_block *b;
+ __le64 *data_le, zero = cpu_to_le64(0);
+ unsigned sb_block_size = dm_bm_block_size(bm) / sizeof(__le64);
+
+ /*
+ * We can't use a validator here - it may be all zeroes.
+ */
+ r = dm_bm_read_lock(bm, SUPERBLOCK_LOCATION, NULL, &b);
+ if (r)
+ return r;
+
+ data_le = dm_block_data(b);
+ *result = true;
+ for (i = 0; i < sb_block_size; i++) {
+ if (data_le[i] != zero) {
+ *result = false;
+ break;
+ }
+ }
+
+ return dm_bm_unlock(b);
+}
+
+/*----------------------------------------------------------------*/
+
+static void ws_pack(const struct writeset_metadata *core, struct writeset_disk *disk)
+{
+ disk->nr_bits = cpu_to_le32(core->nr_bits);
+ disk->root = cpu_to_le64(core->root);
+}
+
+static void ws_unpack(const struct writeset_disk *disk, struct writeset_metadata *core)
+{
+ core->nr_bits = le32_to_cpu(disk->nr_bits);
+ core->root = le64_to_cpu(disk->root);
+}
+
+static void ws_inc(void *context, const void *value)
+{
+ struct era_metadata *md = context;
+ struct writeset_disk ws_d;
+ dm_block_t b;
+
+ memcpy(&ws_d, value, sizeof(ws_d));
+ b = le64_to_cpu(ws_d.root);
+
+ dm_tm_inc(md->tm, b);
+}
+
+static void ws_dec(void *context, const void *value)
+{
+ struct era_metadata *md = context;
+ struct writeset_disk ws_d;
+ dm_block_t b;
+
+ memcpy(&ws_d, value, sizeof(ws_d));
+ b = le64_to_cpu(ws_d.root);
+
+ dm_bitset_del(&md->bitset_info, b);
+}
+
+static int ws_eq(void *context, const void *value1, const void *value2)
+{
+ return !memcmp(value1, value2, sizeof(struct writeset_metadata));
+}
+
+/*----------------------------------------------------------------*/
+
+static void setup_writeset_tree_info(struct era_metadata *md)
+{
+ struct dm_btree_value_type *vt = &md->writeset_tree_info.value_type;
+ md->writeset_tree_info.tm = md->tm;
+ md->writeset_tree_info.levels = 1;
+ vt->context = md;
+ vt->size = sizeof(struct writeset_disk);
+ vt->inc = ws_inc;
+ vt->dec = ws_dec;
+ vt->equal = ws_eq;
+}
+
+static void setup_era_array_info(struct era_metadata *md)
+
+{
+ struct dm_btree_value_type vt;
+ vt.context = NULL;
+ vt.size = sizeof(__le32);
+ vt.inc = NULL;
+ vt.dec = NULL;
+ vt.equal = NULL;
+
+ dm_array_info_init(&md->era_array_info, md->tm, &vt);
+}
+
+static void setup_infos(struct era_metadata *md)
+{
+ dm_disk_bitset_init(md->tm, &md->bitset_info);
+ setup_writeset_tree_info(md);
+ setup_era_array_info(md);
+}
+
+/*----------------------------------------------------------------*/
+
+static int create_fresh_metadata(struct era_metadata *md)
+{
+ int r;
+
+ r = dm_tm_create_with_sm(md->bm, SUPERBLOCK_LOCATION,
+ &md->tm, &md->sm);
+ if (r < 0) {
+ DMERR("dm_tm_create_with_sm failed");
+ return r;
+ }
+
+ setup_infos(md);
+
+ r = dm_btree_empty(&md->writeset_tree_info, &md->writeset_tree_root);
+ if (r) {
+ DMERR("couldn't create new writeset tree");
+ goto bad;
+ }
+
+ r = dm_array_empty(&md->era_array_info, &md->era_array_root);
+ if (r) {
+ DMERR("couldn't create era array");
+ goto bad;
+ }
+
+ return 0;
+
+bad:
+ dm_sm_destroy(md->sm);
+ dm_tm_destroy(md->tm);
+
+ return r;
+}
+
+static int save_sm_root(struct era_metadata *md)
+{
+ int r;
+ size_t metadata_len;
+
+ r = dm_sm_root_size(md->sm, &metadata_len);
+ if (r < 0)
+ return r;
+
+ return dm_sm_copy_root(md->sm, &md->metadata_space_map_root,
+ metadata_len);
+}
+
+static void copy_sm_root(struct era_metadata *md, struct superblock_disk *disk)
+{
+ memcpy(&disk->metadata_space_map_root,
+ &md->metadata_space_map_root,
+ sizeof(md->metadata_space_map_root));
+}
+
+/*
+ * Writes a superblock, including the static fields that don't get updated
+ * with every commit (possible optimisation here). 'md' should be fully
+ * constructed when this is called.
+ */
+static void prepare_superblock(struct era_metadata *md, struct superblock_disk *disk)
+{
+ disk->magic = cpu_to_le64(SUPERBLOCK_MAGIC);
+ disk->flags = cpu_to_le32(0ul);
+
+ /* FIXME: can't keep blanking the uuid (uuid is currently unused though) */
+ memset(disk->uuid, 0, sizeof(disk->uuid));
+ disk->version = cpu_to_le32(MAX_ERA_VERSION);
+
+ copy_sm_root(md, disk);
+
+ disk->data_block_size = cpu_to_le32(md->block_size);
+ disk->metadata_block_size = cpu_to_le32(DM_ERA_METADATA_BLOCK_SIZE >> SECTOR_SHIFT);
+ disk->nr_blocks = cpu_to_le32(md->nr_blocks);
+ disk->current_era = cpu_to_le32(md->current_era);
+
+ ws_pack(&md->current_writeset->md, &disk->current_writeset);
+ disk->writeset_tree_root = cpu_to_le64(md->writeset_tree_root);
+ disk->era_array_root = cpu_to_le64(md->era_array_root);
+ disk->metadata_snap = cpu_to_le64(md->metadata_snap);
+}
+
+static int write_superblock(struct era_metadata *md)
+{
+ int r;
+ struct dm_block *sblock;
+ struct superblock_disk *disk;
+
+ r = save_sm_root(md);
+ if (r) {
+ DMERR("%s: save_sm_root failed", __func__);
+ return r;
+ }
+
+ r = superblock_lock_zero(md, &sblock);
+ if (r)
+ return r;
+
+ disk = dm_block_data(sblock);
+ prepare_superblock(md, disk);
+
+ return dm_tm_commit(md->tm, sblock);
+}
+
+/*
+ * Assumes block_size and the infos are set.
+ */
+static int format_metadata(struct era_metadata *md)
+{
+ int r;
+
+ r = create_fresh_metadata(md);
+ if (r)
+ return r;
+
+ r = write_superblock(md);
+ if (r) {
+ dm_sm_destroy(md->sm);
+ dm_tm_destroy(md->tm);
+ return r;
+ }
+
+ return 0;
+}
+
+static int open_metadata(struct era_metadata *md)
+{
+ int r;
+ struct dm_block *sblock;
+ struct superblock_disk *disk;
+
+ r = superblock_read_lock(md, &sblock);
+ if (r) {
+ DMERR("couldn't read_lock superblock");
+ return r;
+ }
+
+ disk = dm_block_data(sblock);
+ r = dm_tm_open_with_sm(md->bm, SUPERBLOCK_LOCATION,
+ disk->metadata_space_map_root,
+ sizeof(disk->metadata_space_map_root),
+ &md->tm, &md->sm);
+ if (r) {
+ DMERR("dm_tm_open_with_sm failed");
+ goto bad;
+ }
+
+ setup_infos(md);
+
+ md->block_size = le32_to_cpu(disk->data_block_size);
+ md->nr_blocks = le32_to_cpu(disk->nr_blocks);
+ md->current_era = le32_to_cpu(disk->current_era);
+
+ md->writeset_tree_root = le64_to_cpu(disk->writeset_tree_root);
+ md->era_array_root = le64_to_cpu(disk->era_array_root);
+ md->metadata_snap = le64_to_cpu(disk->metadata_snap);
+ md->archived_writesets = true;
+
+ return dm_bm_unlock(sblock);
+
+bad:
+ dm_bm_unlock(sblock);
+ return r;
+}
+
+static int open_or_format_metadata(struct era_metadata *md,
+ bool may_format)
+{
+ int r;
+ bool unformatted = false;
+
+ r = superblock_all_zeroes(md->bm, &unformatted);
+ if (r)
+ return r;
+
+ if (unformatted)
+ return may_format ? format_metadata(md) : -EPERM;
+
+ return open_metadata(md);
+}
+
+static int create_persistent_data_objects(struct era_metadata *md,
+ bool may_format)
+{
+ int r;
+
+ md->bm = dm_block_manager_create(md->bdev, DM_ERA_METADATA_BLOCK_SIZE,
+ DM_ERA_METADATA_CACHE_SIZE,
+ ERA_MAX_CONCURRENT_LOCKS);
+ if (IS_ERR(md->bm)) {
+ DMERR("could not create block manager");
+ return PTR_ERR(md->bm);
+ }
+
+ r = open_or_format_metadata(md, may_format);
+ if (r)
+ dm_block_manager_destroy(md->bm);
+
+ return r;
+}
+
+static void destroy_persistent_data_objects(struct era_metadata *md)
+{
+ dm_sm_destroy(md->sm);
+ dm_tm_destroy(md->tm);
+ dm_block_manager_destroy(md->bm);
+}
+
+/*
+ * This waits until all era_map threads have picked up the new filter.
+ */
+static void swap_writeset(struct era_metadata *md, struct writeset *new_writeset)
+{
+ rcu_assign_pointer(md->current_writeset, new_writeset);
+ synchronize_rcu();
+}
+
+/*----------------------------------------------------------------
+ * Writesets get 'digested' into the main era array.
+ *
+ * We're using a coroutine here so the worker thread can do the digestion,
+ * thus avoiding synchronisation of the metadata. Digesting a whole
+ * writeset in one go would cause too much latency.
+ *--------------------------------------------------------------*/
+struct digest {
+ uint32_t era;
+ unsigned nr_bits, current_bit;
+ struct writeset_metadata writeset;
+ __le32 value;
+ struct dm_disk_bitset info;
+
+ int (*step)(struct era_metadata *, struct digest *);
+};
+
+static int metadata_digest_lookup_writeset(struct era_metadata *md,
+ struct digest *d);
+
+static int metadata_digest_remove_writeset(struct era_metadata *md,
+ struct digest *d)
+{
+ int r;
+ uint64_t key = d->era;
+
+ r = dm_btree_remove(&md->writeset_tree_info, md->writeset_tree_root,
+ &key, &md->writeset_tree_root);
+ if (r) {
+ DMERR("%s: dm_btree_remove failed", __func__);
+ return r;
+ }
+
+ d->step = metadata_digest_lookup_writeset;
+ return 0;
+}
+
+#define INSERTS_PER_STEP 100
+
+static int metadata_digest_transcribe_writeset(struct era_metadata *md,
+ struct digest *d)
+{
+ int r;
+ bool marked;
+ unsigned b, e = min(d->current_bit + INSERTS_PER_STEP, d->nr_bits);
+
+ for (b = d->current_bit; b < e; b++) {
+ r = writeset_marked_on_disk(&d->info, &d->writeset, b, &marked);
+ if (r) {
+ DMERR("%s: writeset_marked_on_disk failed", __func__);
+ return r;
+ }
+
+ if (!marked)
+ continue;
+
+ __dm_bless_for_disk(&d->value);
+ r = dm_array_set_value(&md->era_array_info, md->era_array_root,
+ b, &d->value, &md->era_array_root);
+ if (r) {
+ DMERR("%s: dm_array_set_value failed", __func__);
+ return r;
+ }
+ }
+
+ if (b == d->nr_bits)
+ d->step = metadata_digest_remove_writeset;
+ else
+ d->current_bit = b;
+
+ return 0;
+}
+
+static int metadata_digest_lookup_writeset(struct era_metadata *md,
+ struct digest *d)
+{
+ int r;
+ uint64_t key;
+ struct writeset_disk disk;
+
+ r = dm_btree_find_lowest_key(&md->writeset_tree_info,
+ md->writeset_tree_root, &key);
+ if (r < 0)
+ return r;
+
+ d->era = key;
+
+ r = dm_btree_lookup(&md->writeset_tree_info,
+ md->writeset_tree_root, &key, &disk);
+ if (r) {
+ if (r == -ENODATA) {
+ d->step = NULL;
+ return 0;
+ }
+
+ DMERR("%s: dm_btree_lookup failed", __func__);
+ return r;
+ }
+
+ ws_unpack(&disk, &d->writeset);
+ d->value = cpu_to_le32(key);
+
+ d->nr_bits = min(d->writeset.nr_bits, md->nr_blocks);
+ d->current_bit = 0;
+ d->step = metadata_digest_transcribe_writeset;
+
+ return 0;
+}
+
+static int metadata_digest_start(struct era_metadata *md, struct digest *d)
+{
+ if (d->step)
+ return 0;
+
+ memset(d, 0, sizeof(*d));
+
+ /*
+ * We initialise another bitset info to avoid any caching side
+ * effects with the previous one.
+ */
+ dm_disk_bitset_init(md->tm, &d->info);
+ d->step = metadata_digest_lookup_writeset;
+
+ return 0;
+}
+
+/*----------------------------------------------------------------
+ * High level metadata interface. Target methods should use these, and not
+ * the lower level ones.
+ *--------------------------------------------------------------*/
+static struct era_metadata *metadata_open(struct block_device *bdev,
+ sector_t block_size,
+ bool may_format)
+{
+ int r;
+ struct era_metadata *md = kzalloc(sizeof(*md), GFP_KERNEL);
+
+ if (!md)
+ return NULL;
+
+ md->bdev = bdev;
+ md->block_size = block_size;
+
+ md->writesets[0].md.root = INVALID_WRITESET_ROOT;
+ md->writesets[1].md.root = INVALID_WRITESET_ROOT;
+ md->current_writeset = &md->writesets[0];
+
+ r = create_persistent_data_objects(md, may_format);
+ if (r) {
+ kfree(md);
+ return ERR_PTR(r);
+ }
+
+ return md;
+}
+
+static void metadata_close(struct era_metadata *md)
+{
+ destroy_persistent_data_objects(md);
+ kfree(md);
+}
+
+static bool valid_nr_blocks(dm_block_t n)
+{
+ /*
+ * dm_bitset restricts us to 2^32. test_bit & co. restrict us
+ * further to 2^31 - 1
+ */
+ return n < (1ull << 31);
+}
+
+static int metadata_resize(struct era_metadata *md, void *arg)
+{
+ int r;
+ dm_block_t *new_size = arg;
+ __le32 value;
+
+ if (!valid_nr_blocks(*new_size)) {
+ DMERR("Invalid number of origin blocks %llu",
+ (unsigned long long) *new_size);
+ return -EINVAL;
+ }
+
+ writeset_free(&md->writesets[0]);
+ writeset_free(&md->writesets[1]);
+
+ r = writeset_alloc(&md->writesets[0], *new_size);
+ if (r) {
+ DMERR("%s: writeset_alloc failed for writeset 0", __func__);
+ return r;
+ }
+
+ r = writeset_alloc(&md->writesets[1], *new_size);
+ if (r) {
+ DMERR("%s: writeset_alloc failed for writeset 1", __func__);
+ return r;
+ }
+
+ value = cpu_to_le32(0u);
+ __dm_bless_for_disk(&value);
+ r = dm_array_resize(&md->era_array_info, md->era_array_root,
+ md->nr_blocks, *new_size,
+ &value, &md->era_array_root);
+ if (r) {
+ DMERR("%s: dm_array_resize failed", __func__);
+ return r;
+ }
+
+ md->nr_blocks = *new_size;
+ return 0;
+}
+
+static int metadata_era_archive(struct era_metadata *md)
+{
+ int r;
+ uint64_t keys[1];
+ struct writeset_disk value;
+
+ r = dm_bitset_flush(&md->bitset_info, md->current_writeset->md.root,
+ &md->current_writeset->md.root);
+ if (r) {
+ DMERR("%s: dm_bitset_flush failed", __func__);
+ return r;
+ }
+
+ ws_pack(&md->current_writeset->md, &value);
+ md->current_writeset->md.root = INVALID_WRITESET_ROOT;
+
+ keys[0] = md->current_era;
+ __dm_bless_for_disk(&value);
+ r = dm_btree_insert(&md->writeset_tree_info, md->writeset_tree_root,
+ keys, &value, &md->writeset_tree_root);
+ if (r) {
+ DMERR("%s: couldn't insert writeset into btree", __func__);
+ /* FIXME: fail mode */
+ return r;
+ }
+
+ md->archived_writesets = true;
+
+ return 0;
+}
+
+static struct writeset *next_writeset(struct era_metadata *md)
+{
+ return (md->current_writeset == &md->writesets[0]) ?
+ &md->writesets[1] : &md->writesets[0];
+}
+
+static int metadata_new_era(struct era_metadata *md)
+{
+ int r;
+ struct writeset *new_writeset = next_writeset(md);
+
+ r = writeset_init(&md->bitset_info, new_writeset);
+ if (r) {
+ DMERR("%s: writeset_init failed", __func__);
+ return r;
+ }
+
+ swap_writeset(md, new_writeset);
+ md->current_era++;
+
+ return 0;
+}
+
+static int metadata_era_rollover(struct era_metadata *md)
+{
+ int r;
+
+ if (md->current_writeset->md.root != INVALID_WRITESET_ROOT) {
+ r = metadata_era_archive(md);
+ if (r) {
+ DMERR("%s: metadata_archive_era failed", __func__);
+ /* FIXME: fail mode? */
+ return r;
+ }
+ }
+
+ r = metadata_new_era(md);
+ if (r) {
+ DMERR("%s: new era failed", __func__);
+ /* FIXME: fail mode */
+ return r;
+ }
+
+ return 0;
+}
+
+static bool metadata_current_marked(struct era_metadata *md, dm_block_t block)
+{
+ bool r;
+ struct writeset *ws;
+
+ rcu_read_lock();
+ ws = rcu_dereference(md->current_writeset);
+ r = writeset_marked(ws, block);
+ rcu_read_unlock();
+
+ return r;
+}
+
+static int metadata_commit(struct era_metadata *md)
+{
+ int r;
+ struct dm_block *sblock;
+
+ if (md->current_writeset->md.root != SUPERBLOCK_LOCATION) {
+ r = dm_bitset_flush(&md->bitset_info, md->current_writeset->md.root,
+ &md->current_writeset->md.root);
+ if (r) {
+ DMERR("%s: bitset flush failed", __func__);
+ return r;
+ }
+ }
+
+ r = save_sm_root(md);
+ if (r) {
+ DMERR("%s: save_sm_root failed", __func__);
+ return r;
+ }
+
+ r = dm_tm_pre_commit(md->tm);
+ if (r) {
+ DMERR("%s: pre commit failed", __func__);
+ return r;
+ }
+
+ r = superblock_lock(md, &sblock);
+ if (r) {
+ DMERR("%s: superblock lock failed", __func__);
+ return r;
+ }
+
+ prepare_superblock(md, dm_block_data(sblock));
+
+ return dm_tm_commit(md->tm, sblock);
+}
+
+static int metadata_checkpoint(struct era_metadata *md)
+{
+ /*
+ * For now we just rollover, but later I want to put a check in to
+ * avoid this if the filter is still pretty fresh.
+ */
+ return metadata_era_rollover(md);
+}
+
+/*
+ * Metadata snapshots allow userland to access era data.
+ */
+static int metadata_take_snap(struct era_metadata *md)
+{
+ int r, inc;
+ struct dm_block *clone;
+
+ if (md->metadata_snap != SUPERBLOCK_LOCATION) {
+ DMERR("%s: metadata snapshot already exists", __func__);
+ return -EINVAL;
+ }
+
+ r = metadata_era_rollover(md);
+ if (r) {
+ DMERR("%s: era rollover failed", __func__);
+ return r;
+ }
+
+ r = metadata_commit(md);
+ if (r) {
+ DMERR("%s: pre commit failed", __func__);
+ return r;
+ }
+
+ r = dm_sm_inc_block(md->sm, SUPERBLOCK_LOCATION);
+ if (r) {
+ DMERR("%s: couldn't increment superblock", __func__);
+ return r;
+ }
+
+ r = dm_tm_shadow_block(md->tm, SUPERBLOCK_LOCATION,
+ &sb_validator, &clone, &inc);
+ if (r) {
+ DMERR("%s: couldn't shadow superblock", __func__);
+ dm_sm_dec_block(md->sm, SUPERBLOCK_LOCATION);
+ return r;
+ }
+ BUG_ON(!inc);
+
+ r = dm_sm_inc_block(md->sm, md->writeset_tree_root);
+ if (r) {
+ DMERR("%s: couldn't inc writeset tree root", __func__);
+ dm_tm_unlock(md->tm, clone);
+ return r;
+ }
+
+ r = dm_sm_inc_block(md->sm, md->era_array_root);
+ if (r) {
+ DMERR("%s: couldn't inc era tree root", __func__);
+ dm_sm_dec_block(md->sm, md->writeset_tree_root);
+ dm_tm_unlock(md->tm, clone);
+ return r;
+ }
+
+ md->metadata_snap = dm_block_location(clone);
+
+ r = dm_tm_unlock(md->tm, clone);
+ if (r) {
+ DMERR("%s: couldn't unlock clone", __func__);
+ md->metadata_snap = SUPERBLOCK_LOCATION;
+ return r;
+ }
+
+ return 0;
+}
+
+static int metadata_drop_snap(struct era_metadata *md)
+{
+ int r;
+ dm_block_t location;
+ struct dm_block *clone;
+ struct superblock_disk *disk;
+
+ if (md->metadata_snap == SUPERBLOCK_LOCATION) {
+ DMERR("%s: no snap to drop", __func__);
+ return -EINVAL;
+ }
+
+ r = dm_tm_read_lock(md->tm, md->metadata_snap, &sb_validator, &clone);
+ if (r) {
+ DMERR("%s: couldn't read lock superblock clone", __func__);
+ return r;
+ }
+
+ /*
+ * Whatever happens now we'll commit with no record of the metadata
+ * snap.
+ */
+ md->metadata_snap = SUPERBLOCK_LOCATION;
+
+ disk = dm_block_data(clone);
+ r = dm_btree_del(&md->writeset_tree_info,
+ le64_to_cpu(disk->writeset_tree_root));
+ if (r) {
+ DMERR("%s: error deleting writeset tree clone", __func__);
+ dm_tm_unlock(md->tm, clone);
+ return r;
+ }
+
+ r = dm_array_del(&md->era_array_info, le64_to_cpu(disk->era_array_root));
+ if (r) {
+ DMERR("%s: error deleting era array clone", __func__);
+ dm_tm_unlock(md->tm, clone);
+ return r;
+ }
+
+ location = dm_block_location(clone);
+ dm_tm_unlock(md->tm, clone);
+
+ return dm_sm_dec_block(md->sm, location);
+}
+
+struct metadata_stats {
+ dm_block_t used;
+ dm_block_t total;
+ dm_block_t snap;
+ uint32_t era;
+};
+
+static int metadata_get_stats(struct era_metadata *md, void *ptr)
+{
+ int r;
+ struct metadata_stats *s = ptr;
+ dm_block_t nr_free, nr_total;
+
+ r = dm_sm_get_nr_free(md->sm, &nr_free);
+ if (r) {
+ DMERR("dm_sm_get_nr_free returned %d", r);
+ return r;
+ }
+
+ r = dm_sm_get_nr_blocks(md->sm, &nr_total);
+ if (r) {
+ DMERR("dm_pool_get_metadata_dev_size returned %d", r);
+ return r;
+ }
+
+ s->used = nr_total - nr_free;
+ s->total = nr_total;
+ s->snap = md->metadata_snap;
+ s->era = md->current_era;
+
+ return 0;
+}
+
+/*----------------------------------------------------------------*/
+
+struct era {
+ struct dm_target *ti;
+ struct dm_target_callbacks callbacks;
+
+ struct dm_dev *metadata_dev;
+ struct dm_dev *origin_dev;
+
+ dm_block_t nr_blocks;
+ uint32_t sectors_per_block;
+ int sectors_per_block_shift;
+ struct era_metadata *md;
+
+ struct workqueue_struct *wq;
+ struct work_struct worker;
+
+ spinlock_t deferred_lock;
+ struct bio_list deferred_bios;
+
+ spinlock_t rpc_lock;
+ struct list_head rpc_calls;
+
+ struct digest digest;
+ atomic_t suspended;
+};
+
+struct rpc {
+ struct list_head list;
+
+ int (*fn0)(struct era_metadata *);
+ int (*fn1)(struct era_metadata *, void *);
+ void *arg;
+ int result;
+
+ struct completion complete;
+};
+
+/*----------------------------------------------------------------
+ * Remapping.
+ *---------------------------------------------------------------*/
+static bool block_size_is_power_of_two(struct era *era)
+{
+ return era->sectors_per_block_shift >= 0;
+}
+
+static dm_block_t get_block(struct era *era, struct bio *bio)
+{
+ sector_t block_nr = bio->bi_iter.bi_sector;
+
+ if (!block_size_is_power_of_two(era))
+ (void) sector_div(block_nr, era->sectors_per_block);
+ else
+ block_nr >>= era->sectors_per_block_shift;
+
+ return block_nr;
+}
+
+static void remap_to_origin(struct era *era, struct bio *bio)
+{
+ bio->bi_bdev = era->origin_dev->bdev;
+}
+
+/*----------------------------------------------------------------
+ * Worker thread
+ *--------------------------------------------------------------*/
+static void wake_worker(struct era *era)
+{
+ if (!atomic_read(&era->suspended))
+ queue_work(era->wq, &era->worker);
+}
+
+static void process_old_eras(struct era *era)
+{
+ int r;
+
+ if (!era->digest.step)
+ return;
+
+ r = era->digest.step(era->md, &era->digest);
+ if (r < 0) {
+ DMERR("%s: digest step failed, stopping digestion", __func__);
+ era->digest.step = NULL;
+
+ } else if (era->digest.step)
+ wake_worker(era);
+}
+
+static void process_deferred_bios(struct era *era)
+{
+ int r;
+ struct bio_list deferred_bios, marked_bios;
+ struct bio *bio;
+ bool commit_needed = false;
+ bool failed = false;
+
+ bio_list_init(&deferred_bios);
+ bio_list_init(&marked_bios);
+
+ spin_lock(&era->deferred_lock);
+ bio_list_merge(&deferred_bios, &era->deferred_bios);
+ bio_list_init(&era->deferred_bios);
+ spin_unlock(&era->deferred_lock);
+
+ while ((bio = bio_list_pop(&deferred_bios))) {
+ r = writeset_test_and_set(&era->md->bitset_info,
+ era->md->current_writeset,
+ get_block(era, bio));
+ if (r < 0) {
+ /*
+ * This is bad news, we need to rollback.
+ * FIXME: finish.
+ */
+ failed = true;
+
+ } else if (r == 0)
+ commit_needed = true;
+
+ bio_list_add(&marked_bios, bio);
+ }
+
+ if (commit_needed) {
+ r = metadata_commit(era->md);
+ if (r)
+ failed = true;
+ }
+
+ if (failed)
+ while ((bio = bio_list_pop(&marked_bios)))
+ bio_io_error(bio);
+ else
+ while ((bio = bio_list_pop(&marked_bios)))
+ generic_make_request(bio);
+}
+
+static void process_rpc_calls(struct era *era)
+{
+ int r;
+ bool need_commit = false;
+ struct list_head calls;
+ struct rpc *rpc, *tmp;
+
+ INIT_LIST_HEAD(&calls);
+ spin_lock(&era->rpc_lock);
+ list_splice_init(&era->rpc_calls, &calls);
+ spin_unlock(&era->rpc_lock);
+
+ list_for_each_entry_safe(rpc, tmp, &calls, list) {
+ rpc->result = rpc->fn0 ? rpc->fn0(era->md) : rpc->fn1(era->md, rpc->arg);
+ need_commit = true;
+ }
+
+ if (need_commit) {
+ r = metadata_commit(era->md);
+ if (r)
+ list_for_each_entry_safe(rpc, tmp, &calls, list)
+ rpc->result = r;
+ }
+
+ list_for_each_entry_safe(rpc, tmp, &calls, list)
+ complete(&rpc->complete);
+}
+
+static void kick_off_digest(struct era *era)
+{
+ if (era->md->archived_writesets) {
+ era->md->archived_writesets = false;
+ metadata_digest_start(era->md, &era->digest);
+ }
+}
+
+static void do_work(struct work_struct *ws)
+{
+ struct era *era = container_of(ws, struct era, worker);
+
+ kick_off_digest(era);
+ process_old_eras(era);
+ process_deferred_bios(era);
+ process_rpc_calls(era);
+}
+
+static void defer_bio(struct era *era, struct bio *bio)
+{
+ spin_lock(&era->deferred_lock);
+ bio_list_add(&era->deferred_bios, bio);
+ spin_unlock(&era->deferred_lock);
+
+ wake_worker(era);
+}
+
+/*
+ * Make an rpc call to the worker to change the metadata.
+ */
+static int perform_rpc(struct era *era, struct rpc *rpc)
+{
+ rpc->result = 0;
+ init_completion(&rpc->complete);
+
+ spin_lock(&era->rpc_lock);
+ list_add(&rpc->list, &era->rpc_calls);
+ spin_unlock(&era->rpc_lock);
+
+ wake_worker(era);
+ wait_for_completion(&rpc->complete);
+
+ return rpc->result;
+}
+
+static int in_worker0(struct era *era, int (*fn)(struct era_metadata *))
+{
+ struct rpc rpc;
+ rpc.fn0 = fn;
+ rpc.fn1 = NULL;
+
+ return perform_rpc(era, &rpc);
+}
+
+static int in_worker1(struct era *era,
+ int (*fn)(struct era_metadata *, void *), void *arg)
+{
+ struct rpc rpc;
+ rpc.fn0 = NULL;
+ rpc.fn1 = fn;
+ rpc.arg = arg;
+
+ return perform_rpc(era, &rpc);
+}
+
+static void start_worker(struct era *era)
+{
+ atomic_set(&era->suspended, 0);
+}
+
+static void stop_worker(struct era *era)
+{
+ atomic_set(&era->suspended, 1);
+ flush_workqueue(era->wq);
+}
+
+/*----------------------------------------------------------------
+ * Target methods
+ *--------------------------------------------------------------*/
+static int dev_is_congested(struct dm_dev *dev, int bdi_bits)
+{
+ struct request_queue *q = bdev_get_queue(dev->bdev);
+ return bdi_congested(&q->backing_dev_info, bdi_bits);
+}
+
+static int era_is_congested(struct dm_target_callbacks *cb, int bdi_bits)
+{
+ struct era *era = container_of(cb, struct era, callbacks);
+ return dev_is_congested(era->origin_dev, bdi_bits);
+}
+
+static void era_destroy(struct era *era)
+{
+ metadata_close(era->md);
+
+ if (era->wq)
+ destroy_workqueue(era->wq);
+
+ if (era->origin_dev)
+ dm_put_device(era->ti, era->origin_dev);
+
+ if (era->metadata_dev)
+ dm_put_device(era->ti, era->metadata_dev);
+
+ kfree(era);
+}
+
+static dm_block_t calc_nr_blocks(struct era *era)
+{
+ return dm_sector_div_up(era->ti->len, era->sectors_per_block);
+}
+
+static bool valid_block_size(dm_block_t block_size)
+{
+ bool greater_than_zero = block_size > 0;
+ bool multiple_of_min_block_size = (block_size & (MIN_BLOCK_SIZE - 1)) == 0;
+
+ return greater_than_zero && multiple_of_min_block_size;
+}
+
+/*
+ * <metadata dev> <data dev> <data block size (sectors)>
+ */
+static int era_ctr(struct dm_target *ti, unsigned argc, char **argv)
+{
+ int r;
+ char dummy;
+ struct era *era;
+ struct era_metadata *md;
+
+ if (argc != 3) {
+ ti->error = "Invalid argument count";
+ return -EINVAL;
+ }
+
+ era = kzalloc(sizeof(*era), GFP_KERNEL);
+ if (!era) {
+ ti->error = "Error allocating era structure";
+ return -ENOMEM;
+ }
+
+ era->ti = ti;
+
+ r = dm_get_device(ti, argv[0], FMODE_READ | FMODE_WRITE, &era->metadata_dev);
+ if (r) {
+ ti->error = "Error opening metadata device";
+ era_destroy(era);
+ return -EINVAL;
+ }
+
+ r = dm_get_device(ti, argv[1], FMODE_READ | FMODE_WRITE, &era->origin_dev);
+ if (r) {
+ ti->error = "Error opening data device";
+ era_destroy(era);
+ return -EINVAL;
+ }
+
+ r = sscanf(argv[2], "%u%c", &era->sectors_per_block, &dummy);
+ if (r != 1) {
+ ti->error = "Error parsing block size";
+ era_destroy(era);
+ return -EINVAL;
+ }
+
+ r = dm_set_target_max_io_len(ti, era->sectors_per_block);
+ if (r) {
+ ti->error = "could not set max io len";
+ era_destroy(era);
+ return -EINVAL;
+ }
+
+ if (!valid_block_size(era->sectors_per_block)) {
+ ti->error = "Invalid block size";
+ era_destroy(era);
+ return -EINVAL;
+ }
+ if (era->sectors_per_block & (era->sectors_per_block - 1))
+ era->sectors_per_block_shift = -1;
+ else
+ era->sectors_per_block_shift = __ffs(era->sectors_per_block);
+
+ md = metadata_open(era->metadata_dev->bdev, era->sectors_per_block, true);
+ if (IS_ERR(md)) {
+ ti->error = "Error reading metadata";
+ era_destroy(era);
+ return PTR_ERR(md);
+ }
+ era->md = md;
+
+ era->nr_blocks = calc_nr_blocks(era);
+
+ r = metadata_resize(era->md, &era->nr_blocks);
+ if (r) {
+ ti->error = "couldn't resize metadata";
+ era_destroy(era);
+ return -ENOMEM;
+ }
+
+ era->wq = alloc_ordered_workqueue("dm-" DM_MSG_PREFIX, WQ_MEM_RECLAIM);
+ if (!era->wq) {
+ ti->error = "could not create workqueue for metadata object";
+ era_destroy(era);
+ return -ENOMEM;
+ }
+ INIT_WORK(&era->worker, do_work);
+
+ spin_lock_init(&era->deferred_lock);
+ bio_list_init(&era->deferred_bios);
+
+ spin_lock_init(&era->rpc_lock);
+ INIT_LIST_HEAD(&era->rpc_calls);
+
+ ti->private = era;
+ ti->num_flush_bios = 1;
+ ti->flush_supported = true;
+
+ ti->num_discard_bios = 1;
+ ti->discards_supported = true;
+ era->callbacks.congested_fn = era_is_congested;
+ dm_table_add_target_callbacks(ti->table, &era->callbacks);
+
+ return 0;
+}
+
+static void era_dtr(struct dm_target *ti)
+{
+ era_destroy(ti->private);
+}
+
+static int era_map(struct dm_target *ti, struct bio *bio)
+{
+ struct era *era = ti->private;
+ dm_block_t block = get_block(era, bio);
+
+ /*
+ * All bios get remapped to the origin device. We do this now, but
+ * it may not get issued until later. Depending on whether the
+ * block is marked in this era.
+ */
+ remap_to_origin(era, bio);
+
+ /*
+ * REQ_FLUSH bios carry no data, so we're not interested in them.
+ */
+ if (!(bio->bi_rw & REQ_FLUSH) &&
+ (bio_data_dir(bio) == WRITE) &&
+ !metadata_current_marked(era->md, block)) {
+ defer_bio(era, bio);
+ return DM_MAPIO_SUBMITTED;
+ }
+
+ return DM_MAPIO_REMAPPED;
+}
+
+static void era_postsuspend(struct dm_target *ti)
+{
+ int r;
+ struct era *era = ti->private;
+
+ r = in_worker0(era, metadata_era_archive);
+ if (r) {
+ DMERR("%s: couldn't archive current era", __func__);
+ /* FIXME: fail mode */
+ }
+
+ stop_worker(era);
+}
+
+static int era_preresume(struct dm_target *ti)
+{
+ int r;
+ struct era *era = ti->private;
+ dm_block_t new_size = calc_nr_blocks(era);
+
+ if (era->nr_blocks != new_size) {
+ r = in_worker1(era, metadata_resize, &new_size);
+ if (r)
+ return r;
+
+ era->nr_blocks = new_size;
+ }
+
+ start_worker(era);
+
+ r = in_worker0(era, metadata_new_era);
+ if (r) {
+ DMERR("%s: metadata_era_rollover failed", __func__);
+ return r;
+ }
+
+ return 0;
+}
+
+/*
+ * Status format:
+ *
+ * <metadata block size> <#used metadata blocks>/<#total metadata blocks>
+ * <current era> <held metadata root | '-'>
+ */
+static void era_status(struct dm_target *ti, status_type_t type,
+ unsigned status_flags, char *result, unsigned maxlen)
+{
+ int r;
+ struct era *era = ti->private;
+ ssize_t sz = 0;
+ struct metadata_stats stats;
+ char buf[BDEVNAME_SIZE];
+
+ switch (type) {
+ case STATUSTYPE_INFO:
+ r = in_worker1(era, metadata_get_stats, &stats);
+ if (r)
+ goto err;
+
+ DMEMIT("%u %llu/%llu %u",
+ (unsigned) (DM_ERA_METADATA_BLOCK_SIZE >> SECTOR_SHIFT),
+ (unsigned long long) stats.used,
+ (unsigned long long) stats.total,
+ (unsigned) stats.era);
+
+ if (stats.snap != SUPERBLOCK_LOCATION)
+ DMEMIT(" %llu", stats.snap);
+ else
+ DMEMIT(" -");
+ break;
+
+ case STATUSTYPE_TABLE:
+ format_dev_t(buf, era->metadata_dev->bdev->bd_dev);
+ DMEMIT("%s ", buf);
+ format_dev_t(buf, era->origin_dev->bdev->bd_dev);
+ DMEMIT("%s %u", buf, era->sectors_per_block);
+ break;
+ }
+
+ return;
+
+err:
+ DMEMIT("Error");
+}
+
+static int era_message(struct dm_target *ti, unsigned argc, char **argv)
+{
+ struct era *era = ti->private;
+
+ if (argc != 1) {
+ DMERR("incorrect number of message arguments");
+ return -EINVAL;
+ }
+
+ if (!strcasecmp(argv[0], "checkpoint"))
+ return in_worker0(era, metadata_checkpoint);
+
+ if (!strcasecmp(argv[0], "take_metadata_snap"))
+ return in_worker0(era, metadata_take_snap);
+
+ if (!strcasecmp(argv[0], "drop_metadata_snap"))
+ return in_worker0(era, metadata_drop_snap);
+
+ DMERR("unsupported message '%s'", argv[0]);
+ return -EINVAL;
+}
+
+static sector_t get_dev_size(struct dm_dev *dev)
+{
+ return i_size_read(dev->bdev->bd_inode) >> SECTOR_SHIFT;
+}
+
+static int era_iterate_devices(struct dm_target *ti,
+ iterate_devices_callout_fn fn, void *data)
+{
+ struct era *era = ti->private;
+ return fn(ti, era->origin_dev, 0, get_dev_size(era->origin_dev), data);
+}
+
+static int era_merge(struct dm_target *ti, struct bvec_merge_data *bvm,
+ struct bio_vec *biovec, int max_size)
+{
+ struct era *era = ti->private;
+ struct request_queue *q = bdev_get_queue(era->origin_dev->bdev);
+
+ if (!q->merge_bvec_fn)
+ return max_size;
+
+ bvm->bi_bdev = era->origin_dev->bdev;
+
+ return min(max_size, q->merge_bvec_fn(q, bvm, biovec));
+}
+
+static void era_io_hints(struct dm_target *ti, struct queue_limits *limits)
+{
+ struct era *era = ti->private;
+ uint64_t io_opt_sectors = limits->io_opt >> SECTOR_SHIFT;
+
+ /*
+ * If the system-determined stacked limits are compatible with the
+ * era device's blocksize (io_opt is a factor) do not override them.
+ */
+ if (io_opt_sectors < era->sectors_per_block ||
+ do_div(io_opt_sectors, era->sectors_per_block)) {
+ blk_limits_io_min(limits, 0);
+ blk_limits_io_opt(limits, era->sectors_per_block << SECTOR_SHIFT);
+ }
+}
+
+/*----------------------------------------------------------------*/
+
+static struct target_type era_target = {
+ .name = "era",
+ .version = {1, 0, 0},
+ .module = THIS_MODULE,
+ .ctr = era_ctr,
+ .dtr = era_dtr,
+ .map = era_map,
+ .postsuspend = era_postsuspend,
+ .preresume = era_preresume,
+ .status = era_status,
+ .message = era_message,
+ .iterate_devices = era_iterate_devices,
+ .merge = era_merge,
+ .io_hints = era_io_hints
+};
+
+static int __init dm_era_init(void)
+{
+ int r;
+
+ r = dm_register_target(&era_target);
+ if (r) {
+ DMERR("era target registration failed: %d", r);
+ return r;
+ }
+
+ return 0;
+}
+
+static void __exit dm_era_exit(void)
+{
+ dm_unregister_target(&era_target);
+}
+
+module_init(dm_era_init);
+module_exit(dm_era_exit);
+
+MODULE_DESCRIPTION(DM_NAME " era target");
+MODULE_AUTHOR("Joe Thornber <ejt@redhat.com>");
+MODULE_LICENSE("GPL");
unsigned pg_init_count; /* Number of times pg_init called */
unsigned pg_init_delay_msecs; /* Number of msecs before pg_init retry */
- unsigned queue_size;
- struct work_struct process_queued_ios;
- struct list_head queued_ios;
-
struct work_struct trigger_event;
/*
static struct kmem_cache *_mpio_cache;
static struct workqueue_struct *kmultipathd, *kmpath_handlerd;
-static void process_queued_ios(struct work_struct *work);
static void trigger_event(struct work_struct *work);
static void activate_path(struct work_struct *work);
+static int __pgpath_busy(struct pgpath *pgpath);
/*-----------------------------------------------
m = kzalloc(sizeof(*m), GFP_KERNEL);
if (m) {
INIT_LIST_HEAD(&m->priority_groups);
- INIT_LIST_HEAD(&m->queued_ios);
spin_lock_init(&m->lock);
m->queue_io = 1;
m->pg_init_delay_msecs = DM_PG_INIT_DELAY_DEFAULT;
- INIT_WORK(&m->process_queued_ios, process_queued_ios);
INIT_WORK(&m->trigger_event, trigger_event);
init_waitqueue_head(&m->pg_init_wait);
mutex_init(&m->work_mutex);
* Path selection
*-----------------------------------------------*/
-static void __pg_init_all_paths(struct multipath *m)
+static int __pg_init_all_paths(struct multipath *m)
{
struct pgpath *pgpath;
unsigned long pg_init_delay = 0;
+ if (m->pg_init_in_progress || m->pg_init_disabled)
+ return 0;
+
m->pg_init_count++;
m->pg_init_required = 0;
+
+ /* Check here to reset pg_init_required */
+ if (!m->current_pg)
+ return 0;
+
if (m->pg_init_delay_retry)
pg_init_delay = msecs_to_jiffies(m->pg_init_delay_msecs != DM_PG_INIT_DELAY_DEFAULT ?
m->pg_init_delay_msecs : DM_PG_INIT_DELAY_MSECS);
pg_init_delay))
m->pg_init_in_progress++;
}
+ return m->pg_init_in_progress;
}
static void __switch_pg(struct multipath *m, struct pgpath *pgpath)
*/
static int __must_push_back(struct multipath *m)
{
- return (m->queue_if_no_path != m->saved_queue_if_no_path &&
- dm_noflush_suspending(m->ti));
+ return (m->queue_if_no_path ||
+ (m->queue_if_no_path != m->saved_queue_if_no_path &&
+ dm_noflush_suspending(m->ti)));
}
-static int map_io(struct multipath *m, struct request *clone,
- union map_info *map_context, unsigned was_queued)
+#define pg_ready(m) (!(m)->queue_io && !(m)->pg_init_required)
+
+/*
+ * Map cloned requests
+ */
+static int multipath_map(struct dm_target *ti, struct request *clone,
+ union map_info *map_context)
{
- int r = DM_MAPIO_REMAPPED;
+ struct multipath *m = (struct multipath *) ti->private;
+ int r = DM_MAPIO_REQUEUE;
size_t nr_bytes = blk_rq_bytes(clone);
unsigned long flags;
struct pgpath *pgpath;
struct block_device *bdev;
- struct dm_mpath_io *mpio = map_context->ptr;
+ struct dm_mpath_io *mpio;
spin_lock_irqsave(&m->lock, flags);
pgpath = m->current_pgpath;
- if (was_queued)
- m->queue_size--;
-
- if (m->pg_init_required) {
- if (!m->pg_init_in_progress)
- queue_work(kmultipathd, &m->process_queued_ios);
- r = DM_MAPIO_REQUEUE;
- } else if ((pgpath && m->queue_io) ||
- (!pgpath && m->queue_if_no_path)) {
- /* Queue for the daemon to resubmit */
- list_add_tail(&clone->queuelist, &m->queued_ios);
- m->queue_size++;
- if (!m->queue_io)
- queue_work(kmultipathd, &m->process_queued_ios);
- pgpath = NULL;
- r = DM_MAPIO_SUBMITTED;
- } else if (pgpath) {
- bdev = pgpath->path.dev->bdev;
- clone->q = bdev_get_queue(bdev);
- clone->rq_disk = bdev->bd_disk;
- } else if (__must_push_back(m))
- r = DM_MAPIO_REQUEUE;
- else
- r = -EIO; /* Failed */
+ if (!pgpath) {
+ if (!__must_push_back(m))
+ r = -EIO; /* Failed */
+ goto out_unlock;
+ }
+ if (!pg_ready(m)) {
+ __pg_init_all_paths(m);
+ goto out_unlock;
+ }
+ if (set_mapinfo(m, map_context) < 0)
+ /* ENOMEM, requeue */
+ goto out_unlock;
+ bdev = pgpath->path.dev->bdev;
+ clone->q = bdev_get_queue(bdev);
+ clone->rq_disk = bdev->bd_disk;
+ clone->cmd_flags |= REQ_FAILFAST_TRANSPORT;
+ mpio = map_context->ptr;
mpio->pgpath = pgpath;
mpio->nr_bytes = nr_bytes;
-
- if (r == DM_MAPIO_REMAPPED && pgpath->pg->ps.type->start_io)
- pgpath->pg->ps.type->start_io(&pgpath->pg->ps, &pgpath->path,
+ if (pgpath->pg->ps.type->start_io)
+ pgpath->pg->ps.type->start_io(&pgpath->pg->ps,
+ &pgpath->path,
nr_bytes);
+ r = DM_MAPIO_REMAPPED;
+out_unlock:
spin_unlock_irqrestore(&m->lock, flags);
return r;
else
m->saved_queue_if_no_path = queue_if_no_path;
m->queue_if_no_path = queue_if_no_path;
- if (!m->queue_if_no_path && m->queue_size)
- queue_work(kmultipathd, &m->process_queued_ios);
+ if (!m->queue_if_no_path)
+ dm_table_run_md_queue_async(m->ti->table);
spin_unlock_irqrestore(&m->lock, flags);
return 0;
}
-/*-----------------------------------------------------------------
- * The multipath daemon is responsible for resubmitting queued ios.
- *---------------------------------------------------------------*/
-
-static void dispatch_queued_ios(struct multipath *m)
-{
- int r;
- unsigned long flags;
- union map_info *info;
- struct request *clone, *n;
- LIST_HEAD(cl);
-
- spin_lock_irqsave(&m->lock, flags);
- list_splice_init(&m->queued_ios, &cl);
- spin_unlock_irqrestore(&m->lock, flags);
-
- list_for_each_entry_safe(clone, n, &cl, queuelist) {
- list_del_init(&clone->queuelist);
-
- info = dm_get_rq_mapinfo(clone);
-
- r = map_io(m, clone, info, 1);
- if (r < 0) {
- clear_mapinfo(m, info);
- dm_kill_unmapped_request(clone, r);
- } else if (r == DM_MAPIO_REMAPPED)
- dm_dispatch_request(clone);
- else if (r == DM_MAPIO_REQUEUE) {
- clear_mapinfo(m, info);
- dm_requeue_unmapped_request(clone);
- }
- }
-}
-
-static void process_queued_ios(struct work_struct *work)
-{
- struct multipath *m =
- container_of(work, struct multipath, process_queued_ios);
- struct pgpath *pgpath = NULL;
- unsigned must_queue = 1;
- unsigned long flags;
-
- spin_lock_irqsave(&m->lock, flags);
-
- if (!m->current_pgpath)
- __choose_pgpath(m, 0);
-
- pgpath = m->current_pgpath;
-
- if ((pgpath && !m->queue_io) ||
- (!pgpath && !m->queue_if_no_path))
- must_queue = 0;
-
- if (m->pg_init_required && !m->pg_init_in_progress && pgpath &&
- !m->pg_init_disabled)
- __pg_init_all_paths(m);
-
- spin_unlock_irqrestore(&m->lock, flags);
- if (!must_queue)
- dispatch_queued_ios(m);
-}
-
/*
* An event is triggered whenever a path is taken out of use.
* Includes path failure and PG bypass.
free_multipath(m);
}
-/*
- * Map cloned requests
- */
-static int multipath_map(struct dm_target *ti, struct request *clone,
- union map_info *map_context)
-{
- int r;
- struct multipath *m = (struct multipath *) ti->private;
-
- if (set_mapinfo(m, map_context) < 0)
- /* ENOMEM, requeue */
- return DM_MAPIO_REQUEUE;
-
- clone->cmd_flags |= REQ_FAILFAST_TRANSPORT;
- r = map_io(m, clone, map_context, 0);
- if (r < 0 || r == DM_MAPIO_REQUEUE)
- clear_mapinfo(m, map_context);
-
- return r;
-}
-
/*
* Take a path out of use.
*/
pgpath->is_active = 1;
- if (!m->nr_valid_paths++ && m->queue_size) {
+ if (!m->nr_valid_paths++) {
m->current_pgpath = NULL;
- queue_work(kmultipathd, &m->process_queued_ios);
+ dm_table_run_md_queue_async(m->ti->table);
} else if (m->hw_handler_name && (m->current_pg == pgpath->pg)) {
if (queue_work(kmpath_handlerd, &pgpath->activate_path.work))
m->pg_init_in_progress++;
/* Activations of other paths are still on going */
goto out;
- if (!m->pg_init_required)
- m->queue_io = 0;
-
- m->pg_init_delay_retry = delay_retry;
- queue_work(kmultipathd, &m->process_queued_ios);
+ if (m->pg_init_required) {
+ m->pg_init_delay_retry = delay_retry;
+ if (__pg_init_all_paths(m))
+ goto out;
+ }
+ m->queue_io = 0;
/*
* Wake up any thread waiting to suspend.
struct pgpath *pgpath =
container_of(work, struct pgpath, activate_path.work);
- scsi_dh_activate(bdev_get_queue(pgpath->path.dev->bdev),
- pg_init_done, pgpath);
+ if (pgpath->is_active)
+ scsi_dh_activate(bdev_get_queue(pgpath->path.dev->bdev),
+ pg_init_done, pgpath);
+ else
+ pg_init_done(pgpath, SCSI_DH_DEV_OFFLINED);
}
static int noretry_error(int error)
/* Features */
if (type == STATUSTYPE_INFO)
- DMEMIT("2 %u %u ", m->queue_size, m->pg_init_count);
+ DMEMIT("2 %u %u ", m->queue_io, m->pg_init_count);
else {
DMEMIT("%u ", m->queue_if_no_path +
(m->pg_init_retries > 0) * 2 +
}
if (argc != 2) {
- DMWARN("Unrecognised multipath message received.");
+ DMWARN("Invalid multipath message arguments. Expected 2 arguments, got %d.", argc);
goto out;
}
else if (!strcasecmp(argv[0], "fail_path"))
action = fail_path;
else {
- DMWARN("Unrecognised multipath message received.");
+ DMWARN("Unrecognised multipath message received: %s", argv[0]);
goto out;
}
r = err;
}
- if (r == -ENOTCONN && !fatal_signal_pending(current))
- queue_work(kmultipathd, &m->process_queued_ios);
+ if (r == -ENOTCONN && !fatal_signal_pending(current)) {
+ spin_lock_irqsave(&m->lock, flags);
+ if (!m->current_pg) {
+ /* Path status changed, redo selection */
+ __choose_pgpath(m, 0);
+ }
+ if (m->pg_init_required)
+ __pg_init_all_paths(m);
+ spin_unlock_irqrestore(&m->lock, flags);
+ dm_table_run_md_queue_async(m->ti->table);
+ }
return r ? : __blkdev_driver_ioctl(bdev, mode, cmd, arg);
}
spin_lock_irqsave(&m->lock, flags);
/* pg_init in progress, requeue until done */
- if (m->pg_init_in_progress) {
+ if (!pg_ready(m)) {
busy = 1;
goto out;
}
*---------------------------------------------------------------*/
static struct target_type multipath_target = {
.name = "multipath",
- .version = {1, 6, 0},
+ .version = {1, 7, 0},
.module = THIS_MODULE,
.ctr = multipath_ctr,
.dtr = multipath_dtr,
return dm_table_get_type(t) == DM_TYPE_REQUEST_BASED;
}
-int dm_table_alloc_md_mempools(struct dm_table *t)
+static int dm_table_alloc_md_mempools(struct dm_table *t)
{
unsigned type = dm_table_get_type(t);
unsigned per_bio_data_size = 0;
}
EXPORT_SYMBOL(dm_table_get_md);
+void dm_table_run_md_queue_async(struct dm_table *t)
+{
+ struct mapped_device *md;
+ struct request_queue *queue;
+ unsigned long flags;
+
+ if (!dm_table_request_based(t))
+ return;
+
+ md = dm_table_get_md(t);
+ queue = dm_get_md_queue(md);
+ if (queue) {
+ spin_lock_irqsave(queue->queue_lock, flags);
+ blk_run_queue_async(queue);
+ spin_unlock_irqrestore(queue->queue_lock, flags);
+ }
+}
+EXPORT_SYMBOL(dm_table_run_md_queue_async);
+
static int device_discard_capable(struct dm_target *ti, struct dm_dev *dev,
sector_t start, sector_t len, void *data)
{
* operation possible in this state is the closing of the device.
*/
bool fail_io:1;
+
+ /*
+ * Reading the space map roots can fail, so we read it into these
+ * buffers before the superblock is locked and updated.
+ */
+ __u8 data_space_map_root[SPACE_MAP_ROOT_SIZE];
+ __u8 metadata_space_map_root[SPACE_MAP_ROOT_SIZE];
};
struct dm_thin_device {
pmd->details_info.value_type.equal = NULL;
}
+static int save_sm_roots(struct dm_pool_metadata *pmd)
+{
+ int r;
+ size_t len;
+
+ r = dm_sm_root_size(pmd->metadata_sm, &len);
+ if (r < 0)
+ return r;
+
+ r = dm_sm_copy_root(pmd->metadata_sm, &pmd->metadata_space_map_root, len);
+ if (r < 0)
+ return r;
+
+ r = dm_sm_root_size(pmd->data_sm, &len);
+ if (r < 0)
+ return r;
+
+ return dm_sm_copy_root(pmd->data_sm, &pmd->data_space_map_root, len);
+}
+
+static void copy_sm_roots(struct dm_pool_metadata *pmd,
+ struct thin_disk_superblock *disk)
+{
+ memcpy(&disk->metadata_space_map_root,
+ &pmd->metadata_space_map_root,
+ sizeof(pmd->metadata_space_map_root));
+
+ memcpy(&disk->data_space_map_root,
+ &pmd->data_space_map_root,
+ sizeof(pmd->data_space_map_root));
+}
+
static int __write_initial_superblock(struct dm_pool_metadata *pmd)
{
int r;
struct dm_block *sblock;
- size_t metadata_len, data_len;
struct thin_disk_superblock *disk_super;
sector_t bdev_size = i_size_read(pmd->bdev->bd_inode) >> SECTOR_SHIFT;
if (bdev_size > THIN_METADATA_MAX_SECTORS)
bdev_size = THIN_METADATA_MAX_SECTORS;
- r = dm_sm_root_size(pmd->metadata_sm, &metadata_len);
- if (r < 0)
- return r;
-
- r = dm_sm_root_size(pmd->data_sm, &data_len);
+ r = dm_sm_commit(pmd->data_sm);
if (r < 0)
return r;
- r = dm_sm_commit(pmd->data_sm);
+ r = save_sm_roots(pmd);
if (r < 0)
return r;
disk_super->trans_id = 0;
disk_super->held_root = 0;
- r = dm_sm_copy_root(pmd->metadata_sm, &disk_super->metadata_space_map_root,
- metadata_len);
- if (r < 0)
- goto bad_locked;
-
- r = dm_sm_copy_root(pmd->data_sm, &disk_super->data_space_map_root,
- data_len);
- if (r < 0)
- goto bad_locked;
+ copy_sm_roots(pmd, disk_super);
disk_super->data_mapping_root = cpu_to_le64(pmd->root);
disk_super->device_details_root = cpu_to_le64(pmd->details_root);
disk_super->data_block_size = cpu_to_le32(pmd->data_block_size);
return dm_tm_commit(pmd->tm, sblock);
-
-bad_locked:
- dm_bm_unlock(sblock);
- return r;
}
static int __format_metadata(struct dm_pool_metadata *pmd)
if (r < 0)
return r;
+ r = save_sm_roots(pmd);
+ if (r < 0)
+ return r;
+
r = superblock_lock(pmd, &sblock);
if (r)
return r;
disk_super->trans_id = cpu_to_le64(pmd->trans_id);
disk_super->flags = cpu_to_le32(pmd->flags);
- r = dm_sm_copy_root(pmd->metadata_sm, &disk_super->metadata_space_map_root,
- metadata_len);
- if (r < 0)
- goto out_locked;
-
- r = dm_sm_copy_root(pmd->data_sm, &disk_super->data_space_map_root,
- data_len);
- if (r < 0)
- goto out_locked;
+ copy_sm_roots(pmd, disk_super);
return dm_tm_commit(pmd->tm, sblock);
-
-out_locked:
- dm_bm_unlock(sblock);
- return r;
}
struct dm_pool_metadata *dm_pool_metadata_open(struct block_device *bdev,
#include <linux/dm-io.h>
#include <linux/dm-kcopyd.h>
#include <linux/list.h>
+#include <linux/rculist.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/slab.h>
+#include <linux/rbtree.h>
#define DM_MSG_PREFIX "thin"
unsigned ref_count;
spinlock_t lock;
- struct bio_list deferred_bios;
struct bio_list deferred_flush_bios;
struct list_head prepared_mappings;
struct list_head prepared_discards;
-
- struct bio_list retry_on_resume_list;
+ struct list_head active_thins;
struct dm_deferred_set *shared_read_ds;
struct dm_deferred_set *all_io_ds;
* Target context for a thin.
*/
struct thin_c {
+ struct list_head list;
struct dm_dev *pool_dev;
struct dm_dev *origin_dev;
dm_thin_id dev_id;
struct pool *pool;
struct dm_thin_device *td;
bool requeue_mode:1;
+ spinlock_t lock;
+ struct bio_list deferred_bio_list;
+ struct bio_list retry_on_resume_list;
+ struct rb_root sort_bio_list; /* sorted list of deferred bios */
};
/*----------------------------------------------------------------*/
struct pool *pool = tc->pool;
unsigned long flags;
- spin_lock_irqsave(&pool->lock, flags);
- dm_cell_release_no_holder(pool->prison, cell, &pool->deferred_bios);
- spin_unlock_irqrestore(&pool->lock, flags);
+ spin_lock_irqsave(&tc->lock, flags);
+ dm_cell_release_no_holder(pool->prison, cell, &tc->deferred_bio_list);
+ spin_unlock_irqrestore(&tc->lock, flags);
wake_worker(pool);
}
struct dm_deferred_entry *shared_read_entry;
struct dm_deferred_entry *all_io_entry;
struct dm_thin_new_mapping *overwrite_mapping;
+ struct rb_node rb_node;
};
static void requeue_bio_list(struct thin_c *tc, struct bio_list *master)
bio_list_init(&bios);
- spin_lock_irqsave(&tc->pool->lock, flags);
+ spin_lock_irqsave(&tc->lock, flags);
bio_list_merge(&bios, master);
bio_list_init(master);
- spin_unlock_irqrestore(&tc->pool->lock, flags);
+ spin_unlock_irqrestore(&tc->lock, flags);
- while ((bio = bio_list_pop(&bios))) {
- struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
-
- if (h->tc == tc)
- bio_endio(bio, DM_ENDIO_REQUEUE);
- else
- bio_list_add(master, bio);
- }
+ while ((bio = bio_list_pop(&bios)))
+ bio_endio(bio, DM_ENDIO_REQUEUE);
}
static void requeue_io(struct thin_c *tc)
{
- struct pool *pool = tc->pool;
-
- requeue_bio_list(tc, &pool->deferred_bios);
- requeue_bio_list(tc, &pool->retry_on_resume_list);
+ requeue_bio_list(tc, &tc->deferred_bio_list);
+ requeue_bio_list(tc, &tc->retry_on_resume_list);
}
-static void error_retry_list(struct pool *pool)
+static void error_thin_retry_list(struct thin_c *tc)
{
struct bio *bio;
unsigned long flags;
bio_list_init(&bios);
- spin_lock_irqsave(&pool->lock, flags);
- bio_list_merge(&bios, &pool->retry_on_resume_list);
- bio_list_init(&pool->retry_on_resume_list);
- spin_unlock_irqrestore(&pool->lock, flags);
+ spin_lock_irqsave(&tc->lock, flags);
+ bio_list_merge(&bios, &tc->retry_on_resume_list);
+ bio_list_init(&tc->retry_on_resume_list);
+ spin_unlock_irqrestore(&tc->lock, flags);
while ((bio = bio_list_pop(&bios)))
bio_io_error(bio);
}
+static void error_retry_list(struct pool *pool)
+{
+ struct thin_c *tc;
+
+ rcu_read_lock();
+ list_for_each_entry_rcu(tc, &pool->active_thins, list)
+ error_thin_retry_list(tc);
+ rcu_read_unlock();
+}
+
/*
* This section of code contains the logic for processing a thin device's IO.
* Much of the code depends on pool object resources (lists, workqueues, etc)
struct pool *pool = tc->pool;
unsigned long flags;
- spin_lock_irqsave(&pool->lock, flags);
- cell_release(pool, cell, &pool->deferred_bios);
- spin_unlock_irqrestore(&tc->pool->lock, flags);
+ spin_lock_irqsave(&tc->lock, flags);
+ cell_release(pool, cell, &tc->deferred_bio_list);
+ spin_unlock_irqrestore(&tc->lock, flags);
wake_worker(pool);
}
struct pool *pool = tc->pool;
unsigned long flags;
- spin_lock_irqsave(&pool->lock, flags);
- cell_release_no_holder(pool, cell, &pool->deferred_bios);
- spin_unlock_irqrestore(&pool->lock, flags);
+ spin_lock_irqsave(&tc->lock, flags);
+ cell_release_no_holder(pool, cell, &tc->deferred_bio_list);
+ spin_unlock_irqrestore(&tc->lock, flags);
wake_worker(pool);
}
{
struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
struct thin_c *tc = h->tc;
- struct pool *pool = tc->pool;
unsigned long flags;
- spin_lock_irqsave(&pool->lock, flags);
- bio_list_add(&pool->retry_on_resume_list, bio);
- spin_unlock_irqrestore(&pool->lock, flags);
+ spin_lock_irqsave(&tc->lock, flags);
+ bio_list_add(&tc->retry_on_resume_list, bio);
+ spin_unlock_irqrestore(&tc->lock, flags);
}
static bool should_error_unserviceable_bio(struct pool *pool)
jiffies > pool->last_commit_jiffies + COMMIT_PERIOD;
}
-static void process_deferred_bios(struct pool *pool)
+#define thin_pbd(node) rb_entry((node), struct dm_thin_endio_hook, rb_node)
+#define thin_bio(pbd) dm_bio_from_per_bio_data((pbd), sizeof(struct dm_thin_endio_hook))
+
+static void __thin_bio_rb_add(struct thin_c *tc, struct bio *bio)
+{
+ struct rb_node **rbp, *parent;
+ struct dm_thin_endio_hook *pbd;
+ sector_t bi_sector = bio->bi_iter.bi_sector;
+
+ rbp = &tc->sort_bio_list.rb_node;
+ parent = NULL;
+ while (*rbp) {
+ parent = *rbp;
+ pbd = thin_pbd(parent);
+
+ if (bi_sector < thin_bio(pbd)->bi_iter.bi_sector)
+ rbp = &(*rbp)->rb_left;
+ else
+ rbp = &(*rbp)->rb_right;
+ }
+
+ pbd = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
+ rb_link_node(&pbd->rb_node, parent, rbp);
+ rb_insert_color(&pbd->rb_node, &tc->sort_bio_list);
+}
+
+static void __extract_sorted_bios(struct thin_c *tc)
+{
+ struct rb_node *node;
+ struct dm_thin_endio_hook *pbd;
+ struct bio *bio;
+
+ for (node = rb_first(&tc->sort_bio_list); node; node = rb_next(node)) {
+ pbd = thin_pbd(node);
+ bio = thin_bio(pbd);
+
+ bio_list_add(&tc->deferred_bio_list, bio);
+ rb_erase(&pbd->rb_node, &tc->sort_bio_list);
+ }
+
+ WARN_ON(!RB_EMPTY_ROOT(&tc->sort_bio_list));
+}
+
+static void __sort_thin_deferred_bios(struct thin_c *tc)
+{
+ struct bio *bio;
+ struct bio_list bios;
+
+ bio_list_init(&bios);
+ bio_list_merge(&bios, &tc->deferred_bio_list);
+ bio_list_init(&tc->deferred_bio_list);
+
+ /* Sort deferred_bio_list using rb-tree */
+ while ((bio = bio_list_pop(&bios)))
+ __thin_bio_rb_add(tc, bio);
+
+ /*
+ * Transfer the sorted bios in sort_bio_list back to
+ * deferred_bio_list to allow lockless submission of
+ * all bios.
+ */
+ __extract_sorted_bios(tc);
+}
+
+static void process_thin_deferred_bios(struct thin_c *tc)
{
+ struct pool *pool = tc->pool;
unsigned long flags;
struct bio *bio;
struct bio_list bios;
+ struct blk_plug plug;
+
+ if (tc->requeue_mode) {
+ requeue_bio_list(tc, &tc->deferred_bio_list);
+ return;
+ }
bio_list_init(&bios);
- spin_lock_irqsave(&pool->lock, flags);
- bio_list_merge(&bios, &pool->deferred_bios);
- bio_list_init(&pool->deferred_bios);
- spin_unlock_irqrestore(&pool->lock, flags);
+ spin_lock_irqsave(&tc->lock, flags);
- while ((bio = bio_list_pop(&bios))) {
- struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
- struct thin_c *tc = h->tc;
+ if (bio_list_empty(&tc->deferred_bio_list)) {
+ spin_unlock_irqrestore(&tc->lock, flags);
+ return;
+ }
- if (tc->requeue_mode) {
- bio_endio(bio, DM_ENDIO_REQUEUE);
- continue;
- }
+ __sort_thin_deferred_bios(tc);
+
+ bio_list_merge(&bios, &tc->deferred_bio_list);
+ bio_list_init(&tc->deferred_bio_list);
+ spin_unlock_irqrestore(&tc->lock, flags);
+
+ blk_start_plug(&plug);
+ while ((bio = bio_list_pop(&bios))) {
/*
* If we've got no free new_mapping structs, and processing
* this bio might require one, we pause until there are some
* prepared mappings to process.
*/
if (ensure_next_mapping(pool)) {
- spin_lock_irqsave(&pool->lock, flags);
- bio_list_merge(&pool->deferred_bios, &bios);
- spin_unlock_irqrestore(&pool->lock, flags);
-
+ spin_lock_irqsave(&tc->lock, flags);
+ bio_list_add(&tc->deferred_bio_list, bio);
+ bio_list_merge(&tc->deferred_bio_list, &bios);
+ spin_unlock_irqrestore(&tc->lock, flags);
break;
}
else
pool->process_bio(tc, bio);
}
+ blk_finish_plug(&plug);
+}
+
+static void process_deferred_bios(struct pool *pool)
+{
+ unsigned long flags;
+ struct bio *bio;
+ struct bio_list bios;
+ struct thin_c *tc;
+
+ rcu_read_lock();
+ list_for_each_entry_rcu(tc, &pool->active_thins, list)
+ process_thin_deferred_bios(tc);
+ rcu_read_unlock();
/*
* If there are any deferred flush bios, we must commit
unsigned long flags;
struct pool *pool = tc->pool;
- spin_lock_irqsave(&pool->lock, flags);
- bio_list_add(&pool->deferred_bios, bio);
- spin_unlock_irqrestore(&pool->lock, flags);
+ spin_lock_irqsave(&tc->lock, flags);
+ bio_list_add(&tc->deferred_bio_list, bio);
+ spin_unlock_irqrestore(&tc->lock, flags);
wake_worker(pool);
}
static int pool_is_congested(struct dm_target_callbacks *cb, int bdi_bits)
{
- int r;
- unsigned long flags;
struct pool_c *pt = container_of(cb, struct pool_c, callbacks);
+ struct request_queue *q;
- spin_lock_irqsave(&pt->pool->lock, flags);
- r = !bio_list_empty(&pt->pool->retry_on_resume_list);
- spin_unlock_irqrestore(&pt->pool->lock, flags);
+ if (get_pool_mode(pt->pool) == PM_OUT_OF_DATA_SPACE)
+ return 1;
- if (!r) {
- struct request_queue *q = bdev_get_queue(pt->data_dev->bdev);
- r = bdi_congested(&q->backing_dev_info, bdi_bits);
- }
-
- return r;
+ q = bdev_get_queue(pt->data_dev->bdev);
+ return bdi_congested(&q->backing_dev_info, bdi_bits);
}
-static void __requeue_bios(struct pool *pool)
+static void requeue_bios(struct pool *pool)
{
- bio_list_merge(&pool->deferred_bios, &pool->retry_on_resume_list);
- bio_list_init(&pool->retry_on_resume_list);
+ unsigned long flags;
+ struct thin_c *tc;
+
+ rcu_read_lock();
+ list_for_each_entry_rcu(tc, &pool->active_thins, list) {
+ spin_lock_irqsave(&tc->lock, flags);
+ bio_list_merge(&tc->deferred_bio_list, &tc->retry_on_resume_list);
+ bio_list_init(&tc->retry_on_resume_list);
+ spin_unlock_irqrestore(&tc->lock, flags);
+ }
+ rcu_read_unlock();
}
/*----------------------------------------------------------------
INIT_WORK(&pool->worker, do_worker);
INIT_DELAYED_WORK(&pool->waker, do_waker);
spin_lock_init(&pool->lock);
- bio_list_init(&pool->deferred_bios);
bio_list_init(&pool->deferred_flush_bios);
INIT_LIST_HEAD(&pool->prepared_mappings);
INIT_LIST_HEAD(&pool->prepared_discards);
+ INIT_LIST_HEAD(&pool->active_thins);
pool->low_water_triggered = false;
- bio_list_init(&pool->retry_on_resume_list);
pool->shared_read_ds = dm_deferred_set_create();
if (!pool->shared_read_ds) {
spin_lock_irqsave(&pool->lock, flags);
pool->low_water_triggered = false;
- __requeue_bios(pool);
spin_unlock_irqrestore(&pool->lock, flags);
+ requeue_bios(pool);
do_waker(&pool->waker.work);
}
.name = "thin-pool",
.features = DM_TARGET_SINGLETON | DM_TARGET_ALWAYS_WRITEABLE |
DM_TARGET_IMMUTABLE,
- .version = {1, 11, 0},
+ .version = {1, 12, 0},
.module = THIS_MODULE,
.ctr = pool_ctr,
.dtr = pool_dtr,
static void thin_dtr(struct dm_target *ti)
{
struct thin_c *tc = ti->private;
+ unsigned long flags;
+
+ spin_lock_irqsave(&tc->pool->lock, flags);
+ list_del_rcu(&tc->list);
+ spin_unlock_irqrestore(&tc->pool->lock, flags);
+ synchronize_rcu();
mutex_lock(&dm_thin_pool_table.mutex);
r = -ENOMEM;
goto out_unlock;
}
+ spin_lock_init(&tc->lock);
+ bio_list_init(&tc->deferred_bio_list);
+ bio_list_init(&tc->retry_on_resume_list);
+ tc->sort_bio_list = RB_ROOT;
if (argc == 3) {
r = dm_get_device(ti, argv[2], FMODE_READ, &origin_dev);
mutex_unlock(&dm_thin_pool_table.mutex);
+ spin_lock(&tc->pool->lock);
+ list_add_tail_rcu(&tc->list, &tc->pool->active_thins);
+ spin_unlock(&tc->pool->lock);
+ /*
+ * This synchronize_rcu() call is needed here otherwise we risk a
+ * wake_worker() call finding no bios to process (because the newly
+ * added tc isn't yet visible). So this reduces latency since we
+ * aren't then dependent on the periodic commit to wake_worker().
+ */
+ synchronize_rcu();
+
return 0;
bad_target_max_io_len:
static struct target_type thin_target = {
.name = "thin",
- .version = {1, 11, 0},
+ .version = {1, 12, 0},
.module = THIS_MODULE,
.ctr = thin_ctr,
.dtr = thin_dtr,
struct bio clone;
};
-union map_info *dm_get_mapinfo(struct bio *bio)
-{
- if (bio && bio->bi_private)
- return &((struct dm_target_io *)bio->bi_private)->info;
- return NULL;
-}
-
union map_info *dm_get_rq_mapinfo(struct request *rq)
{
if (rq && rq->end_io_data)
return get_capacity(md->disk);
}
+struct request_queue *dm_get_md_queue(struct mapped_device *md)
+{
+ return md->queue;
+}
+
struct dm_stats *dm_get_stats(struct mapped_device *md)
{
return &md->stats;
static void clone_endio(struct bio *bio, int error)
{
int r = 0;
- struct dm_target_io *tio = bio->bi_private;
+ struct dm_target_io *tio = container_of(bio, struct dm_target_io, clone);
struct dm_io *io = tio->io;
struct mapped_device *md = tio->io->md;
dm_endio_fn endio = tio->ti->type->end_io;
*/
static void end_clone_bio(struct bio *clone, int error)
{
- struct dm_rq_clone_bio_info *info = clone->bi_private;
+ struct dm_rq_clone_bio_info *info =
+ container_of(clone, struct dm_rq_clone_bio_info, clone);
struct dm_rq_target_io *tio = info->tio;
struct bio *bio = info->orig;
unsigned int nr_bytes = info->orig->bi_iter.bi_size;
struct dm_target *ti = tio->ti;
clone->bi_end_io = clone_endio;
- clone->bi_private = tio;
/*
* Map the clone. If r == 0 we don't need to do
tio->io = ci->io;
tio->ti = ti;
- memset(&tio->info, 0, sizeof(tio->info));
tio->target_bio_nr = target_bio_nr;
return tio;
info->orig = bio_orig;
info->tio = tio;
bio->bi_end_io = end_clone_bio;
- bio->bi_private = info;
return 0;
}
return NULL;
dm_table_event_callback(map, NULL, NULL);
- rcu_assign_pointer(md->map, NULL);
+ RCU_INIT_POINTER(md->map, NULL);
dm_sync_table(md);
return map;
.owner = THIS_MODULE
};
-EXPORT_SYMBOL(dm_get_mapinfo);
-
/*
* module hooks
*/
struct target_type *dm_table_get_immutable_target_type(struct dm_table *t);
bool dm_table_request_based(struct dm_table *t);
bool dm_table_supports_discards(struct dm_table *t);
-int dm_table_alloc_md_mempools(struct dm_table *t);
void dm_table_free_md_mempools(struct dm_table *t);
struct dm_md_mempools *dm_table_get_md_mempools(struct dm_table *t);
int dm_cancel_deferred_remove(struct mapped_device *md);
int dm_request_based(struct mapped_device *md);
sector_t dm_get_size(struct mapped_device *md);
+struct request_queue *dm_get_md_queue(struct mapped_device *md);
struct dm_stats *dm_get_stats(struct mapped_device *md);
int dm_kobject_uevent(struct mapped_device *md, enum kobject_action action,
int r;
__le64 value;
- if (!info->current_index_set)
+ if (!info->current_index_set || !info->dirty)
return 0;
value = cpu_to_le64(info->current_bits);
return r;
info->current_index_set = false;
+ info->dirty = false;
+
return 0;
}
EXPORT_SYMBOL_GPL(dm_bitset_flush);
info->current_bits = le64_to_cpu(value);
info->current_index_set = true;
info->current_index = array_index;
+ info->dirty = false;
+
return 0;
}
return r;
set_bit(b, (unsigned long *) &info->current_bits);
+ info->dirty = true;
+
return 0;
}
EXPORT_SYMBOL_GPL(dm_bitset_set_bit);
return r;
clear_bit(b, (unsigned long *) &info->current_bits);
+ info->dirty = true;
+
return 0;
}
EXPORT_SYMBOL_GPL(dm_bitset_clear_bit);
uint64_t current_bits;
bool current_index_set:1;
+ bool dirty:1;
};
/*
}
EXPORT_SYMBOL_GPL(dm_bm_unlock);
-int dm_bm_flush_and_unlock(struct dm_block_manager *bm,
- struct dm_block *superblock)
+int dm_bm_flush(struct dm_block_manager *bm)
{
- int r;
-
if (bm->read_only)
return -EPERM;
- r = dm_bufio_write_dirty_buffers(bm->bufio);
- if (unlikely(r)) {
- dm_bm_unlock(superblock);
- return r;
- }
-
- dm_bm_unlock(superblock);
-
return dm_bufio_write_dirty_buffers(bm->bufio);
}
-EXPORT_SYMBOL_GPL(dm_bm_flush_and_unlock);
+EXPORT_SYMBOL_GPL(dm_bm_flush);
void dm_bm_prefetch(struct dm_block_manager *bm, dm_block_t b)
{
*
* This method always blocks.
*/
-int dm_bm_flush_and_unlock(struct dm_block_manager *bm,
- struct dm_block *superblock);
+int dm_bm_flush(struct dm_block_manager *bm);
/*
* Request data is prefetched into the cache.
if (r < 0)
return r;
- return 0;
+ return dm_bm_flush(tm->bm);
}
EXPORT_SYMBOL_GPL(dm_tm_pre_commit);
return -EWOULDBLOCK;
wipe_shadow_table(tm);
+ dm_bm_unlock(root);
- return dm_bm_flush_and_unlock(tm->bm, root);
+ return dm_bm_flush(tm->bm);
}
EXPORT_SYMBOL_GPL(dm_tm_commit);
/*
* We use a 2-phase commit here.
*
- * i) In the first phase the block manager is told to start flushing, and
- * the changes to the space map are written to disk. You should interrogate
- * your particular space map to get detail of its root node etc. to be
- * included in your superblock.
+ * i) Make all changes for the transaction *except* for the superblock.
+ * Then call dm_tm_pre_commit() to flush them to disk.
*
- * ii) @root will be committed last. You shouldn't use more than the
- * first 512 bytes of @root if you wish the transaction to survive a power
- * failure. You *must* have a write lock held on @root for both stage (i)
- * and (ii). The commit will drop the write lock.
+ * ii) Lock your superblock. Update. Then call dm_tm_commit() which will
+ * unlock the superblock and flush it. No other blocks should be updated
+ * during this period. Care should be taken to never unlock a partially
+ * updated superblock; perform any operations that could fail *before* you
+ * take the superblock lock.
*/
int dm_tm_pre_commit(struct dm_transaction_manager *tm);
-int dm_tm_commit(struct dm_transaction_manager *tm, struct dm_block *root);
+int dm_tm_commit(struct dm_transaction_manager *tm, struct dm_block *superblock);
/*
* These methods are the only way to get hold of a writeable block.
union map_info {
void *ptr;
- unsigned long long ll;
};
/*
struct dm_target_io {
struct dm_io *io;
struct dm_target *ti;
- union map_info info;
unsigned target_bio_nr;
struct bio clone;
};
struct gendisk *dm_disk(struct mapped_device *md);
int dm_suspended(struct dm_target *ti);
int dm_noflush_suspending(struct dm_target *ti);
-union map_info *dm_get_mapinfo(struct bio *bio);
union map_info *dm_get_rq_mapinfo(struct request *rq);
struct queue_limits *dm_get_queue_limits(struct mapped_device *md);
*/
void dm_table_event(struct dm_table *t);
+/*
+ * Run the queue for request-based targets.
+ */
+void dm_table_run_md_queue_async(struct dm_table *t);
+
/*
* The device must be suspended before calling this method.
* Returns the previous table, which the caller must destroy.
projects / firefly-linux-kernel-4.4.55.git / commitdiff