Commit bfc835b5 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'dm-3.19-fixes-2' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm

Pull device mapper fixes from Mike Snitzer:
 "Two stable fixes for dm-cache and one 3.19 DM core fix:

   - fix potential for dm-cache metadata corruption via stale metadata
     buffers being used when switching an inactive cache table to
     active; this could occur due to each table having it's own bufio
     client rather than sharing the client between tables.

   - fix dm-cache target to properly account for discard IO while
     suspending otherwise IO quiescing could complete prematurely.

   - fix DM core's handling of multiple internal suspends by maintaining
     an 'internal_suspend_count' and only resuming the device when this
     count drops to zero"

* tag 'dm-3.19-fixes-2' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm:
  dm: fix handling of multiple internal suspends
  dm cache: fix problematic dual use of a single migration count variable
  dm cache: share cache-metadata object across inactive and active DM tables
parents 8e908e99 96b26c8c
......@@ -94,6 +94,9 @@ struct cache_disk_superblock {
} __packed;
struct dm_cache_metadata {
atomic_t ref_count;
struct list_head list;
struct block_device *bdev;
struct dm_block_manager *bm;
struct dm_space_map *metadata_sm;
......@@ -669,10 +672,10 @@ static void unpack_value(__le64 value_le, dm_oblock_t *block, unsigned *flags)
/*----------------------------------------------------------------*/
struct dm_cache_metadata *dm_cache_metadata_open(struct block_device *bdev,
sector_t data_block_size,
bool may_format_device,
size_t policy_hint_size)
static struct dm_cache_metadata *metadata_open(struct block_device *bdev,
sector_t data_block_size,
bool may_format_device,
size_t policy_hint_size)
{
int r;
struct dm_cache_metadata *cmd;
......@@ -683,6 +686,7 @@ struct dm_cache_metadata *dm_cache_metadata_open(struct block_device *bdev,
return NULL;
}
atomic_set(&cmd->ref_count, 1);
init_rwsem(&cmd->root_lock);
cmd->bdev = bdev;
cmd->data_block_size = data_block_size;
......@@ -705,10 +709,95 @@ struct dm_cache_metadata *dm_cache_metadata_open(struct block_device *bdev,
return cmd;
}
/*
* We keep a little list of ref counted metadata objects to prevent two
* different target instances creating separate bufio instances. This is
* an issue if a table is reloaded before the suspend.
*/
static DEFINE_MUTEX(table_lock);
static LIST_HEAD(table);
static struct dm_cache_metadata *lookup(struct block_device *bdev)
{
struct dm_cache_metadata *cmd;
list_for_each_entry(cmd, &table, list)
if (cmd->bdev == bdev) {
atomic_inc(&cmd->ref_count);
return cmd;
}
return NULL;
}
static struct dm_cache_metadata *lookup_or_open(struct block_device *bdev,
sector_t data_block_size,
bool may_format_device,
size_t policy_hint_size)
{
struct dm_cache_metadata *cmd, *cmd2;
mutex_lock(&table_lock);
cmd = lookup(bdev);
mutex_unlock(&table_lock);
if (cmd)
return cmd;
cmd = metadata_open(bdev, data_block_size, may_format_device, policy_hint_size);
if (cmd) {
mutex_lock(&table_lock);
cmd2 = lookup(bdev);
if (cmd2) {
mutex_unlock(&table_lock);
__destroy_persistent_data_objects(cmd);
kfree(cmd);
return cmd2;
}
list_add(&cmd->list, &table);
mutex_unlock(&table_lock);
}
return cmd;
}
static bool same_params(struct dm_cache_metadata *cmd, sector_t data_block_size)
{
if (cmd->data_block_size != data_block_size) {
DMERR("data_block_size (%llu) different from that in metadata (%llu)\n",
(unsigned long long) data_block_size,
(unsigned long long) cmd->data_block_size);
return false;
}
return true;
}
struct dm_cache_metadata *dm_cache_metadata_open(struct block_device *bdev,
sector_t data_block_size,
bool may_format_device,
size_t policy_hint_size)
{
struct dm_cache_metadata *cmd = lookup_or_open(bdev, data_block_size,
may_format_device, policy_hint_size);
if (cmd && !same_params(cmd, data_block_size)) {
dm_cache_metadata_close(cmd);
return NULL;
}
return cmd;
}
void dm_cache_metadata_close(struct dm_cache_metadata *cmd)
{
__destroy_persistent_data_objects(cmd);
kfree(cmd);
if (atomic_dec_and_test(&cmd->ref_count)) {
mutex_lock(&table_lock);
list_del(&cmd->list);
mutex_unlock(&table_lock);
__destroy_persistent_data_objects(cmd);
kfree(cmd);
}
}
/*
......
......@@ -221,7 +221,13 @@ struct cache {
struct list_head need_commit_migrations;
sector_t migration_threshold;
wait_queue_head_t migration_wait;
atomic_t nr_migrations;
atomic_t nr_allocated_migrations;
/*
* The number of in flight migrations that are performing
* background io. eg, promotion, writeback.
*/
atomic_t nr_io_migrations;
wait_queue_head_t quiescing_wait;
atomic_t quiescing;
......@@ -258,7 +264,6 @@ struct cache {
struct dm_deferred_set *all_io_ds;
mempool_t *migration_pool;
struct dm_cache_migration *next_migration;
struct dm_cache_policy *policy;
unsigned policy_nr_args;
......@@ -350,10 +355,31 @@ static void free_prison_cell(struct cache *cache, struct dm_bio_prison_cell *cel
dm_bio_prison_free_cell(cache->prison, cell);
}
static struct dm_cache_migration *alloc_migration(struct cache *cache)
{
struct dm_cache_migration *mg;
mg = mempool_alloc(cache->migration_pool, GFP_NOWAIT);
if (mg) {
mg->cache = cache;
atomic_inc(&mg->cache->nr_allocated_migrations);
}
return mg;
}
static void free_migration(struct dm_cache_migration *mg)
{
if (atomic_dec_and_test(&mg->cache->nr_allocated_migrations))
wake_up(&mg->cache->migration_wait);
mempool_free(mg, mg->cache->migration_pool);
}
static int prealloc_data_structs(struct cache *cache, struct prealloc *p)
{
if (!p->mg) {
p->mg = mempool_alloc(cache->migration_pool, GFP_NOWAIT);
p->mg = alloc_migration(cache);
if (!p->mg)
return -ENOMEM;
}
......@@ -382,7 +408,7 @@ static void prealloc_free_structs(struct cache *cache, struct prealloc *p)
free_prison_cell(cache, p->cell1);
if (p->mg)
mempool_free(p->mg, cache->migration_pool);
free_migration(p->mg);
}
static struct dm_cache_migration *prealloc_get_migration(struct prealloc *p)
......@@ -854,24 +880,14 @@ static void remap_to_origin_then_cache(struct cache *cache, struct bio *bio,
* Migration covers moving data from the origin device to the cache, or
* vice versa.
*--------------------------------------------------------------*/
static void free_migration(struct dm_cache_migration *mg)
{
mempool_free(mg, mg->cache->migration_pool);
}
static void inc_nr_migrations(struct cache *cache)
static void inc_io_migrations(struct cache *cache)
{
atomic_inc(&cache->nr_migrations);
atomic_inc(&cache->nr_io_migrations);
}
static void dec_nr_migrations(struct cache *cache)
static void dec_io_migrations(struct cache *cache)
{
atomic_dec(&cache->nr_migrations);
/*
* Wake the worker in case we're suspending the target.
*/
wake_up(&cache->migration_wait);
atomic_dec(&cache->nr_io_migrations);
}
static void __cell_defer(struct cache *cache, struct dm_bio_prison_cell *cell,
......@@ -894,11 +910,10 @@ static void cell_defer(struct cache *cache, struct dm_bio_prison_cell *cell,
wake_worker(cache);
}
static void cleanup_migration(struct dm_cache_migration *mg)
static void free_io_migration(struct dm_cache_migration *mg)
{
struct cache *cache = mg->cache;
dec_io_migrations(mg->cache);
free_migration(mg);
dec_nr_migrations(cache);
}
static void migration_failure(struct dm_cache_migration *mg)
......@@ -923,7 +938,7 @@ static void migration_failure(struct dm_cache_migration *mg)
cell_defer(cache, mg->new_ocell, true);
}
cleanup_migration(mg);
free_io_migration(mg);
}
static void migration_success_pre_commit(struct dm_cache_migration *mg)
......@@ -934,7 +949,7 @@ static void migration_success_pre_commit(struct dm_cache_migration *mg)
if (mg->writeback) {
clear_dirty(cache, mg->old_oblock, mg->cblock);
cell_defer(cache, mg->old_ocell, false);
cleanup_migration(mg);
free_io_migration(mg);
return;
} else if (mg->demote) {
......@@ -944,14 +959,14 @@ static void migration_success_pre_commit(struct dm_cache_migration *mg)
mg->old_oblock);
if (mg->promote)
cell_defer(cache, mg->new_ocell, true);
cleanup_migration(mg);
free_io_migration(mg);
return;
}
} else {
if (dm_cache_insert_mapping(cache->cmd, mg->cblock, mg->new_oblock)) {
DMWARN_LIMIT("promotion failed; couldn't update on disk metadata");
policy_remove_mapping(cache->policy, mg->new_oblock);
cleanup_migration(mg);
free_io_migration(mg);
return;
}
}
......@@ -984,7 +999,7 @@ static void migration_success_post_commit(struct dm_cache_migration *mg)
} else {
if (mg->invalidate)
policy_remove_mapping(cache->policy, mg->old_oblock);
cleanup_migration(mg);
free_io_migration(mg);
}
} else {
......@@ -999,7 +1014,7 @@ static void migration_success_post_commit(struct dm_cache_migration *mg)
bio_endio(mg->new_ocell->holder, 0);
cell_defer(cache, mg->new_ocell, false);
}
cleanup_migration(mg);
free_io_migration(mg);
}
}
......@@ -1251,7 +1266,7 @@ static void promote(struct cache *cache, struct prealloc *structs,
mg->new_ocell = cell;
mg->start_jiffies = jiffies;
inc_nr_migrations(cache);
inc_io_migrations(cache);
quiesce_migration(mg);
}
......@@ -1275,7 +1290,7 @@ static void writeback(struct cache *cache, struct prealloc *structs,
mg->new_ocell = NULL;
mg->start_jiffies = jiffies;
inc_nr_migrations(cache);
inc_io_migrations(cache);
quiesce_migration(mg);
}
......@@ -1302,7 +1317,7 @@ static void demote_then_promote(struct cache *cache, struct prealloc *structs,
mg->new_ocell = new_ocell;
mg->start_jiffies = jiffies;
inc_nr_migrations(cache);
inc_io_migrations(cache);
quiesce_migration(mg);
}
......@@ -1330,7 +1345,7 @@ static void invalidate(struct cache *cache, struct prealloc *structs,
mg->new_ocell = NULL;
mg->start_jiffies = jiffies;
inc_nr_migrations(cache);
inc_io_migrations(cache);
quiesce_migration(mg);
}
......@@ -1412,7 +1427,7 @@ static void process_discard_bio(struct cache *cache, struct prealloc *structs,
static bool spare_migration_bandwidth(struct cache *cache)
{
sector_t current_volume = (atomic_read(&cache->nr_migrations) + 1) *
sector_t current_volume = (atomic_read(&cache->nr_io_migrations) + 1) *
cache->sectors_per_block;
return current_volume < cache->migration_threshold;
}
......@@ -1764,7 +1779,7 @@ static void stop_quiescing(struct cache *cache)
static void wait_for_migrations(struct cache *cache)
{
wait_event(cache->migration_wait, !atomic_read(&cache->nr_migrations));
wait_event(cache->migration_wait, !atomic_read(&cache->nr_allocated_migrations));
}
static void stop_worker(struct cache *cache)
......@@ -1876,9 +1891,6 @@ static void destroy(struct cache *cache)
{
unsigned i;
if (cache->next_migration)
mempool_free(cache->next_migration, cache->migration_pool);
if (cache->migration_pool)
mempool_destroy(cache->migration_pool);
......@@ -2424,7 +2436,8 @@ static int cache_create(struct cache_args *ca, struct cache **result)
INIT_LIST_HEAD(&cache->quiesced_migrations);
INIT_LIST_HEAD(&cache->completed_migrations);
INIT_LIST_HEAD(&cache->need_commit_migrations);
atomic_set(&cache->nr_migrations, 0);
atomic_set(&cache->nr_allocated_migrations, 0);
atomic_set(&cache->nr_io_migrations, 0);
init_waitqueue_head(&cache->migration_wait);
init_waitqueue_head(&cache->quiescing_wait);
......@@ -2487,8 +2500,6 @@ static int cache_create(struct cache_args *ca, struct cache **result)
goto bad;
}
cache->next_migration = NULL;
cache->need_tick_bio = true;
cache->sized = false;
cache->invalidate = false;
......
......@@ -206,6 +206,9 @@ struct mapped_device {
/* zero-length flush that will be cloned and submitted to targets */
struct bio flush_bio;
/* the number of internal suspends */
unsigned internal_suspend_count;
struct dm_stats stats;
};
......@@ -2928,7 +2931,7 @@ static void __dm_internal_suspend(struct mapped_device *md, unsigned suspend_fla
{
struct dm_table *map = NULL;
if (dm_suspended_internally_md(md))
if (md->internal_suspend_count++)
return; /* nested internal suspend */
if (dm_suspended_md(md)) {
......@@ -2953,7 +2956,9 @@ static void __dm_internal_suspend(struct mapped_device *md, unsigned suspend_fla
static void __dm_internal_resume(struct mapped_device *md)
{
if (!dm_suspended_internally_md(md))
BUG_ON(!md->internal_suspend_count);
if (--md->internal_suspend_count)
return; /* resume from nested internal suspend */
if (dm_suspended_md(md))
......
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