| /* |
| * Copyright (C) 2011 Red Hat UK. |
| * |
| * This file is released under the GPL. |
| */ |
| |
| #include "dm-thin-metadata.h" |
| |
| #include <linux/device-mapper.h> |
| #include <linux/dm-io.h> |
| #include <linux/dm-kcopyd.h> |
| #include <linux/list.h> |
| #include <linux/init.h> |
| #include <linux/module.h> |
| #include <linux/slab.h> |
| |
| #define DM_MSG_PREFIX "thin" |
| |
| /* |
| * Tunable constants |
| */ |
| #define ENDIO_HOOK_POOL_SIZE 1024 |
| #define DEFERRED_SET_SIZE 64 |
| #define MAPPING_POOL_SIZE 1024 |
| #define PRISON_CELLS 1024 |
| #define COMMIT_PERIOD HZ |
| |
| /* |
| * The block size of the device holding pool data must be |
| * between 64KB and 1GB. |
| */ |
| #define DATA_DEV_BLOCK_SIZE_MIN_SECTORS (64 * 1024 >> SECTOR_SHIFT) |
| #define DATA_DEV_BLOCK_SIZE_MAX_SECTORS (1024 * 1024 * 1024 >> SECTOR_SHIFT) |
| |
| /* |
| * Device id is restricted to 24 bits. |
| */ |
| #define MAX_DEV_ID ((1 << 24) - 1) |
| |
| /* |
| * How do we handle breaking sharing of data blocks? |
| * ================================================= |
| * |
| * We use a standard copy-on-write btree to store the mappings for the |
| * devices (note I'm talking about copy-on-write of the metadata here, not |
| * the data). When you take an internal snapshot you clone the root node |
| * of the origin btree. After this there is no concept of an origin or a |
| * snapshot. They are just two device trees that happen to point to the |
| * same data blocks. |
| * |
| * When we get a write in we decide if it's to a shared data block using |
| * some timestamp magic. If it is, we have to break sharing. |
| * |
| * Let's say we write to a shared block in what was the origin. The |
| * steps are: |
| * |
| * i) plug io further to this physical block. (see bio_prison code). |
| * |
| * ii) quiesce any read io to that shared data block. Obviously |
| * including all devices that share this block. (see deferred_set code) |
| * |
| * iii) copy the data block to a newly allocate block. This step can be |
| * missed out if the io covers the block. (schedule_copy). |
| * |
| * iv) insert the new mapping into the origin's btree |
| * (process_prepared_mapping). This act of inserting breaks some |
| * sharing of btree nodes between the two devices. Breaking sharing only |
| * effects the btree of that specific device. Btrees for the other |
| * devices that share the block never change. The btree for the origin |
| * device as it was after the last commit is untouched, ie. we're using |
| * persistent data structures in the functional programming sense. |
| * |
| * v) unplug io to this physical block, including the io that triggered |
| * the breaking of sharing. |
| * |
| * Steps (ii) and (iii) occur in parallel. |
| * |
| * The metadata _doesn't_ need to be committed before the io continues. We |
| * get away with this because the io is always written to a _new_ block. |
| * If there's a crash, then: |
| * |
| * - The origin mapping will point to the old origin block (the shared |
| * one). This will contain the data as it was before the io that triggered |
| * the breaking of sharing came in. |
| * |
| * - The snap mapping still points to the old block. As it would after |
| * the commit. |
| * |
| * The downside of this scheme is the timestamp magic isn't perfect, and |
| * will continue to think that data block in the snapshot device is shared |
| * even after the write to the origin has broken sharing. I suspect data |
| * blocks will typically be shared by many different devices, so we're |
| * breaking sharing n + 1 times, rather than n, where n is the number of |
| * devices that reference this data block. At the moment I think the |
| * benefits far, far outweigh the disadvantages. |
| */ |
| |
| /*----------------------------------------------------------------*/ |
| |
| /* |
| * Sometimes we can't deal with a bio straight away. We put them in prison |
| * where they can't cause any mischief. Bios are put in a cell identified |
| * by a key, multiple bios can be in the same cell. When the cell is |
| * subsequently unlocked the bios become available. |
| */ |
| struct bio_prison; |
| |
| struct cell_key { |
| int virtual; |
| dm_thin_id dev; |
| dm_block_t block; |
| }; |
| |
| struct dm_bio_prison_cell { |
| struct hlist_node list; |
| struct bio_prison *prison; |
| struct cell_key key; |
| struct bio *holder; |
| struct bio_list bios; |
| }; |
| |
| struct bio_prison { |
| spinlock_t lock; |
| mempool_t *cell_pool; |
| |
| unsigned nr_buckets; |
| unsigned hash_mask; |
| struct hlist_head *cells; |
| }; |
| |
| static uint32_t calc_nr_buckets(unsigned nr_cells) |
| { |
| uint32_t n = 128; |
| |
| nr_cells /= 4; |
| nr_cells = min(nr_cells, 8192u); |
| |
| while (n < nr_cells) |
| n <<= 1; |
| |
| return n; |
| } |
| |
| static struct kmem_cache *_cell_cache; |
| |
| /* |
| * @nr_cells should be the number of cells you want in use _concurrently_. |
| * Don't confuse it with the number of distinct keys. |
| */ |
| static struct bio_prison *prison_create(unsigned nr_cells) |
| { |
| unsigned i; |
| uint32_t nr_buckets = calc_nr_buckets(nr_cells); |
| size_t len = sizeof(struct bio_prison) + |
| (sizeof(struct hlist_head) * nr_buckets); |
| struct bio_prison *prison = kmalloc(len, GFP_KERNEL); |
| |
| if (!prison) |
| return NULL; |
| |
| spin_lock_init(&prison->lock); |
| prison->cell_pool = mempool_create_slab_pool(nr_cells, _cell_cache); |
| if (!prison->cell_pool) { |
| kfree(prison); |
| return NULL; |
| } |
| |
| prison->nr_buckets = nr_buckets; |
| prison->hash_mask = nr_buckets - 1; |
| prison->cells = (struct hlist_head *) (prison + 1); |
| for (i = 0; i < nr_buckets; i++) |
| INIT_HLIST_HEAD(prison->cells + i); |
| |
| return prison; |
| } |
| |
| static void prison_destroy(struct bio_prison *prison) |
| { |
| mempool_destroy(prison->cell_pool); |
| kfree(prison); |
| } |
| |
| static uint32_t hash_key(struct bio_prison *prison, struct cell_key *key) |
| { |
| const unsigned long BIG_PRIME = 4294967291UL; |
| uint64_t hash = key->block * BIG_PRIME; |
| |
| return (uint32_t) (hash & prison->hash_mask); |
| } |
| |
| static int keys_equal(struct cell_key *lhs, struct cell_key *rhs) |
| { |
| return (lhs->virtual == rhs->virtual) && |
| (lhs->dev == rhs->dev) && |
| (lhs->block == rhs->block); |
| } |
| |
| static struct dm_bio_prison_cell *__search_bucket(struct hlist_head *bucket, |
| struct cell_key *key) |
| { |
| struct dm_bio_prison_cell *cell; |
| struct hlist_node *tmp; |
| |
| hlist_for_each_entry(cell, tmp, bucket, list) |
| if (keys_equal(&cell->key, key)) |
| return cell; |
| |
| return NULL; |
| } |
| |
| /* |
| * This may block if a new cell needs allocating. You must ensure that |
| * cells will be unlocked even if the calling thread is blocked. |
| * |
| * Returns 1 if the cell was already held, 0 if @inmate is the new holder. |
| */ |
| static int bio_detain(struct bio_prison *prison, struct cell_key *key, |
| struct bio *inmate, struct dm_bio_prison_cell **ref) |
| { |
| int r = 1; |
| unsigned long flags; |
| uint32_t hash = hash_key(prison, key); |
| struct dm_bio_prison_cell *cell, *cell2; |
| |
| BUG_ON(hash > prison->nr_buckets); |
| |
| spin_lock_irqsave(&prison->lock, flags); |
| |
| cell = __search_bucket(prison->cells + hash, key); |
| if (cell) { |
| bio_list_add(&cell->bios, inmate); |
| goto out; |
| } |
| |
| /* |
| * Allocate a new cell |
| */ |
| spin_unlock_irqrestore(&prison->lock, flags); |
| cell2 = mempool_alloc(prison->cell_pool, GFP_NOIO); |
| spin_lock_irqsave(&prison->lock, flags); |
| |
| /* |
| * We've been unlocked, so we have to double check that |
| * nobody else has inserted this cell in the meantime. |
| */ |
| cell = __search_bucket(prison->cells + hash, key); |
| if (cell) { |
| mempool_free(cell2, prison->cell_pool); |
| bio_list_add(&cell->bios, inmate); |
| goto out; |
| } |
| |
| /* |
| * Use new cell. |
| */ |
| cell = cell2; |
| |
| cell->prison = prison; |
| memcpy(&cell->key, key, sizeof(cell->key)); |
| cell->holder = inmate; |
| bio_list_init(&cell->bios); |
| hlist_add_head(&cell->list, prison->cells + hash); |
| |
| r = 0; |
| |
| out: |
| spin_unlock_irqrestore(&prison->lock, flags); |
| |
| *ref = cell; |
| |
| return r; |
| } |
| |
| /* |
| * @inmates must have been initialised prior to this call |
| */ |
| static void __cell_release(struct dm_bio_prison_cell *cell, struct bio_list *inmates) |
| { |
| struct bio_prison *prison = cell->prison; |
| |
| hlist_del(&cell->list); |
| |
| if (inmates) { |
| bio_list_add(inmates, cell->holder); |
| bio_list_merge(inmates, &cell->bios); |
| } |
| |
| mempool_free(cell, prison->cell_pool); |
| } |
| |
| static void cell_release(struct dm_bio_prison_cell *cell, struct bio_list *bios) |
| { |
| unsigned long flags; |
| struct bio_prison *prison = cell->prison; |
| |
| spin_lock_irqsave(&prison->lock, flags); |
| __cell_release(cell, bios); |
| spin_unlock_irqrestore(&prison->lock, flags); |
| } |
| |
| /* |
| * There are a couple of places where we put a bio into a cell briefly |
| * before taking it out again. In these situations we know that no other |
| * bio may be in the cell. This function releases the cell, and also does |
| * a sanity check. |
| */ |
| static void __cell_release_singleton(struct dm_bio_prison_cell *cell, struct bio *bio) |
| { |
| BUG_ON(cell->holder != bio); |
| BUG_ON(!bio_list_empty(&cell->bios)); |
| |
| __cell_release(cell, NULL); |
| } |
| |
| static void cell_release_singleton(struct dm_bio_prison_cell *cell, struct bio *bio) |
| { |
| unsigned long flags; |
| struct bio_prison *prison = cell->prison; |
| |
| spin_lock_irqsave(&prison->lock, flags); |
| __cell_release_singleton(cell, bio); |
| spin_unlock_irqrestore(&prison->lock, flags); |
| } |
| |
| /* |
| * Sometimes we don't want the holder, just the additional bios. |
| */ |
| static void __cell_release_no_holder(struct dm_bio_prison_cell *cell, |
| struct bio_list *inmates) |
| { |
| struct bio_prison *prison = cell->prison; |
| |
| hlist_del(&cell->list); |
| bio_list_merge(inmates, &cell->bios); |
| |
| mempool_free(cell, prison->cell_pool); |
| } |
| |
| static void cell_release_no_holder(struct dm_bio_prison_cell *cell, |
| struct bio_list *inmates) |
| { |
| unsigned long flags; |
| struct bio_prison *prison = cell->prison; |
| |
| spin_lock_irqsave(&prison->lock, flags); |
| __cell_release_no_holder(cell, inmates); |
| spin_unlock_irqrestore(&prison->lock, flags); |
| } |
| |
| static void cell_error(struct dm_bio_prison_cell *cell) |
| { |
| struct bio_prison *prison = cell->prison; |
| struct bio_list bios; |
| struct bio *bio; |
| unsigned long flags; |
| |
| bio_list_init(&bios); |
| |
| spin_lock_irqsave(&prison->lock, flags); |
| __cell_release(cell, &bios); |
| spin_unlock_irqrestore(&prison->lock, flags); |
| |
| while ((bio = bio_list_pop(&bios))) |
| bio_io_error(bio); |
| } |
| |
| /*----------------------------------------------------------------*/ |
| |
| /* |
| * We use the deferred set to keep track of pending reads to shared blocks. |
| * We do this to ensure the new mapping caused by a write isn't performed |
| * until these prior reads have completed. Otherwise the insertion of the |
| * new mapping could free the old block that the read bios are mapped to. |
| */ |
| |
| struct deferred_set; |
| struct deferred_entry { |
| struct deferred_set *ds; |
| unsigned count; |
| struct list_head work_items; |
| }; |
| |
| struct deferred_set { |
| spinlock_t lock; |
| unsigned current_entry; |
| unsigned sweeper; |
| struct deferred_entry entries[DEFERRED_SET_SIZE]; |
| }; |
| |
| static void ds_init(struct deferred_set *ds) |
| { |
| int i; |
| |
| spin_lock_init(&ds->lock); |
| ds->current_entry = 0; |
| ds->sweeper = 0; |
| for (i = 0; i < DEFERRED_SET_SIZE; i++) { |
| ds->entries[i].ds = ds; |
| ds->entries[i].count = 0; |
| INIT_LIST_HEAD(&ds->entries[i].work_items); |
| } |
| } |
| |
| static struct deferred_entry *ds_inc(struct deferred_set *ds) |
| { |
| unsigned long flags; |
| struct deferred_entry *entry; |
| |
| spin_lock_irqsave(&ds->lock, flags); |
| entry = ds->entries + ds->current_entry; |
| entry->count++; |
| spin_unlock_irqrestore(&ds->lock, flags); |
| |
| return entry; |
| } |
| |
| static unsigned ds_next(unsigned index) |
| { |
| return (index + 1) % DEFERRED_SET_SIZE; |
| } |
| |
| static void __sweep(struct deferred_set *ds, struct list_head *head) |
| { |
| while ((ds->sweeper != ds->current_entry) && |
| !ds->entries[ds->sweeper].count) { |
| list_splice_init(&ds->entries[ds->sweeper].work_items, head); |
| ds->sweeper = ds_next(ds->sweeper); |
| } |
| |
| if ((ds->sweeper == ds->current_entry) && !ds->entries[ds->sweeper].count) |
| list_splice_init(&ds->entries[ds->sweeper].work_items, head); |
| } |
| |
| static void ds_dec(struct deferred_entry *entry, struct list_head *head) |
| { |
| unsigned long flags; |
| |
| spin_lock_irqsave(&entry->ds->lock, flags); |
| BUG_ON(!entry->count); |
| --entry->count; |
| __sweep(entry->ds, head); |
| spin_unlock_irqrestore(&entry->ds->lock, flags); |
| } |
| |
| /* |
| * Returns 1 if deferred or 0 if no pending items to delay job. |
| */ |
| static int ds_add_work(struct deferred_set *ds, struct list_head *work) |
| { |
| int r = 1; |
| unsigned long flags; |
| unsigned next_entry; |
| |
| spin_lock_irqsave(&ds->lock, flags); |
| if ((ds->sweeper == ds->current_entry) && |
| !ds->entries[ds->current_entry].count) |
| r = 0; |
| else { |
| list_add(work, &ds->entries[ds->current_entry].work_items); |
| next_entry = ds_next(ds->current_entry); |
| if (!ds->entries[next_entry].count) |
| ds->current_entry = next_entry; |
| } |
| spin_unlock_irqrestore(&ds->lock, flags); |
| |
| return r; |
| } |
| |
| /*----------------------------------------------------------------*/ |
| |
| /* |
| * Key building. |
| */ |
| static void build_data_key(struct dm_thin_device *td, |
| dm_block_t b, struct cell_key *key) |
| { |
| key->virtual = 0; |
| key->dev = dm_thin_dev_id(td); |
| key->block = b; |
| } |
| |
| static void build_virtual_key(struct dm_thin_device *td, dm_block_t b, |
| struct cell_key *key) |
| { |
| key->virtual = 1; |
| key->dev = dm_thin_dev_id(td); |
| key->block = b; |
| } |
| |
| /*----------------------------------------------------------------*/ |
| |
| /* |
| * A pool device ties together a metadata device and a data device. It |
| * also provides the interface for creating and destroying internal |
| * devices. |
| */ |
| struct dm_thin_new_mapping; |
| |
| struct pool_features { |
| unsigned zero_new_blocks:1; |
| unsigned discard_enabled:1; |
| unsigned discard_passdown:1; |
| }; |
| |
| struct pool { |
| struct list_head list; |
| struct dm_target *ti; /* Only set if a pool target is bound */ |
| |
| struct mapped_device *pool_md; |
| struct block_device *md_dev; |
| struct dm_pool_metadata *pmd; |
| |
| dm_block_t low_water_blocks; |
| uint32_t sectors_per_block; |
| int sectors_per_block_shift; |
| |
| struct pool_features pf; |
| unsigned low_water_triggered:1; /* A dm event has been sent */ |
| unsigned no_free_space:1; /* A -ENOSPC warning has been issued */ |
| |
| struct bio_prison *prison; |
| struct dm_kcopyd_client *copier; |
| |
| struct workqueue_struct *wq; |
| struct work_struct worker; |
| struct delayed_work waker; |
| |
| unsigned long last_commit_jiffies; |
| 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 deferred_set shared_read_ds; |
| struct deferred_set all_io_ds; |
| |
| struct dm_thin_new_mapping *next_mapping; |
| mempool_t *mapping_pool; |
| mempool_t *endio_hook_pool; |
| }; |
| |
| /* |
| * Target context for a pool. |
| */ |
| struct pool_c { |
| struct dm_target *ti; |
| struct pool *pool; |
| struct dm_dev *data_dev; |
| struct dm_dev *metadata_dev; |
| struct dm_target_callbacks callbacks; |
| |
| dm_block_t low_water_blocks; |
| struct pool_features pf; |
| }; |
| |
| /* |
| * Target context for a thin. |
| */ |
| struct thin_c { |
| struct dm_dev *pool_dev; |
| struct dm_dev *origin_dev; |
| dm_thin_id dev_id; |
| |
| struct pool *pool; |
| struct dm_thin_device *td; |
| }; |
| |
| /*----------------------------------------------------------------*/ |
| |
| /* |
| * A global list of pools that uses a struct mapped_device as a key. |
| */ |
| static struct dm_thin_pool_table { |
| struct mutex mutex; |
| struct list_head pools; |
| } dm_thin_pool_table; |
| |
| static void pool_table_init(void) |
| { |
| mutex_init(&dm_thin_pool_table.mutex); |
| INIT_LIST_HEAD(&dm_thin_pool_table.pools); |
| } |
| |
| static void __pool_table_insert(struct pool *pool) |
| { |
| BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex)); |
| list_add(&pool->list, &dm_thin_pool_table.pools); |
| } |
| |
| static void __pool_table_remove(struct pool *pool) |
| { |
| BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex)); |
| list_del(&pool->list); |
| } |
| |
| static struct pool *__pool_table_lookup(struct mapped_device *md) |
| { |
| struct pool *pool = NULL, *tmp; |
| |
| BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex)); |
| |
| list_for_each_entry(tmp, &dm_thin_pool_table.pools, list) { |
| if (tmp->pool_md == md) { |
| pool = tmp; |
| break; |
| } |
| } |
| |
| return pool; |
| } |
| |
| static struct pool *__pool_table_lookup_metadata_dev(struct block_device *md_dev) |
| { |
| struct pool *pool = NULL, *tmp; |
| |
| BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex)); |
| |
| list_for_each_entry(tmp, &dm_thin_pool_table.pools, list) { |
| if (tmp->md_dev == md_dev) { |
| pool = tmp; |
| break; |
| } |
| } |
| |
| return pool; |
| } |
| |
| /*----------------------------------------------------------------*/ |
| |
| struct dm_thin_endio_hook { |
| struct thin_c *tc; |
| struct deferred_entry *shared_read_entry; |
| struct deferred_entry *all_io_entry; |
| struct dm_thin_new_mapping *overwrite_mapping; |
| }; |
| |
| static void __requeue_bio_list(struct thin_c *tc, struct bio_list *master) |
| { |
| struct bio *bio; |
| struct bio_list bios; |
| |
| bio_list_init(&bios); |
| bio_list_merge(&bios, master); |
| bio_list_init(master); |
| |
| while ((bio = bio_list_pop(&bios))) { |
| struct dm_thin_endio_hook *h = dm_get_mapinfo(bio)->ptr; |
| |
| if (h->tc == tc) |
| bio_endio(bio, DM_ENDIO_REQUEUE); |
| else |
| bio_list_add(master, bio); |
| } |
| } |
| |
| static void requeue_io(struct thin_c *tc) |
| { |
| struct pool *pool = tc->pool; |
| unsigned long flags; |
| |
| spin_lock_irqsave(&pool->lock, flags); |
| __requeue_bio_list(tc, &pool->deferred_bios); |
| __requeue_bio_list(tc, &pool->retry_on_resume_list); |
| spin_unlock_irqrestore(&pool->lock, flags); |
| } |
| |
| /* |
| * 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) |
| * but most is exclusively called from the thin target rather than the thin-pool |
| * target. |
| */ |
| |
| static dm_block_t get_bio_block(struct thin_c *tc, struct bio *bio) |
| { |
| sector_t block_nr = bio->bi_sector; |
| |
| if (tc->pool->sectors_per_block_shift < 0) |
| (void) sector_div(block_nr, tc->pool->sectors_per_block); |
| else |
| block_nr >>= tc->pool->sectors_per_block_shift; |
| |
| return block_nr; |
| } |
| |
| static void remap(struct thin_c *tc, struct bio *bio, dm_block_t block) |
| { |
| struct pool *pool = tc->pool; |
| sector_t bi_sector = bio->bi_sector; |
| |
| bio->bi_bdev = tc->pool_dev->bdev; |
| if (tc->pool->sectors_per_block_shift < 0) |
| bio->bi_sector = (block * pool->sectors_per_block) + |
| sector_div(bi_sector, pool->sectors_per_block); |
| else |
| bio->bi_sector = (block << pool->sectors_per_block_shift) | |
| (bi_sector & (pool->sectors_per_block - 1)); |
| } |
| |
| static void remap_to_origin(struct thin_c *tc, struct bio *bio) |
| { |
| bio->bi_bdev = tc->origin_dev->bdev; |
| } |
| |
| static void issue(struct thin_c *tc, struct bio *bio) |
| { |
| struct pool *pool = tc->pool; |
| unsigned long flags; |
| |
| /* |
| * Batch together any FUA/FLUSH bios we find and then issue |
| * a single commit for them in process_deferred_bios(). |
| */ |
| if (bio->bi_rw & (REQ_FLUSH | REQ_FUA)) { |
| spin_lock_irqsave(&pool->lock, flags); |
| bio_list_add(&pool->deferred_flush_bios, bio); |
| spin_unlock_irqrestore(&pool->lock, flags); |
| } else |
| generic_make_request(bio); |
| } |
| |
| static void remap_to_origin_and_issue(struct thin_c *tc, struct bio *bio) |
| { |
| remap_to_origin(tc, bio); |
| issue(tc, bio); |
| } |
| |
| static void remap_and_issue(struct thin_c *tc, struct bio *bio, |
| dm_block_t block) |
| { |
| remap(tc, bio, block); |
| issue(tc, bio); |
| } |
| |
| /* |
| * wake_worker() is used when new work is queued and when pool_resume is |
| * ready to continue deferred IO processing. |
| */ |
| static void wake_worker(struct pool *pool) |
| { |
| queue_work(pool->wq, &pool->worker); |
| } |
| |
| /*----------------------------------------------------------------*/ |
| |
| /* |
| * Bio endio functions. |
| */ |
| struct dm_thin_new_mapping { |
| struct list_head list; |
| |
| unsigned quiesced:1; |
| unsigned prepared:1; |
| unsigned pass_discard:1; |
| |
| struct thin_c *tc; |
| dm_block_t virt_block; |
| dm_block_t data_block; |
| struct dm_bio_prison_cell *cell, *cell2; |
| int err; |
| |
| /* |
| * If the bio covers the whole area of a block then we can avoid |
| * zeroing or copying. Instead this bio is hooked. The bio will |
| * still be in the cell, so care has to be taken to avoid issuing |
| * the bio twice. |
| */ |
| struct bio *bio; |
| bio_end_io_t *saved_bi_end_io; |
| }; |
| |
| static void __maybe_add_mapping(struct dm_thin_new_mapping *m) |
| { |
| struct pool *pool = m->tc->pool; |
| |
| if (m->quiesced && m->prepared) { |
| list_add(&m->list, &pool->prepared_mappings); |
| wake_worker(pool); |
| } |
| } |
| |
| static void copy_complete(int read_err, unsigned long write_err, void *context) |
| { |
| unsigned long flags; |
| struct dm_thin_new_mapping *m = context; |
| struct pool *pool = m->tc->pool; |
| |
| m->err = read_err || write_err ? -EIO : 0; |
| |
| spin_lock_irqsave(&pool->lock, flags); |
| m->prepared = 1; |
| __maybe_add_mapping(m); |
| spin_unlock_irqrestore(&pool->lock, flags); |
| } |
| |
| static void overwrite_endio(struct bio *bio, int err) |
| { |
| unsigned long flags; |
| struct dm_thin_endio_hook *h = dm_get_mapinfo(bio)->ptr; |
| struct dm_thin_new_mapping *m = h->overwrite_mapping; |
| struct pool *pool = m->tc->pool; |
| |
| m->err = err; |
| |
| spin_lock_irqsave(&pool->lock, flags); |
| m->prepared = 1; |
| __maybe_add_mapping(m); |
| spin_unlock_irqrestore(&pool->lock, flags); |
| } |
| |
| /*----------------------------------------------------------------*/ |
| |
| /* |
| * Workqueue. |
| */ |
| |
| /* |
| * Prepared mapping jobs. |
| */ |
| |
| /* |
| * This sends the bios in the cell back to the deferred_bios list. |
| */ |
| static void cell_defer(struct thin_c *tc, struct dm_bio_prison_cell *cell, |
| dm_block_t data_block) |
| { |
| struct pool *pool = tc->pool; |
| unsigned long flags; |
| |
| spin_lock_irqsave(&pool->lock, flags); |
| cell_release(cell, &pool->deferred_bios); |
| spin_unlock_irqrestore(&tc->pool->lock, flags); |
| |
| wake_worker(pool); |
| } |
| |
| /* |
| * Same as cell_defer above, except it omits one particular detainee, |
| * a write bio that covers the block and has already been processed. |
| */ |
| static void cell_defer_except(struct thin_c *tc, struct dm_bio_prison_cell *cell) |
| { |
| struct bio_list bios; |
| struct pool *pool = tc->pool; |
| unsigned long flags; |
| |
| bio_list_init(&bios); |
| |
| spin_lock_irqsave(&pool->lock, flags); |
| cell_release_no_holder(cell, &pool->deferred_bios); |
| spin_unlock_irqrestore(&pool->lock, flags); |
| |
| wake_worker(pool); |
| } |
| |
| static void process_prepared_mapping(struct dm_thin_new_mapping *m) |
| { |
| struct thin_c *tc = m->tc; |
| struct bio *bio; |
| int r; |
| |
| bio = m->bio; |
| if (bio) |
| bio->bi_end_io = m->saved_bi_end_io; |
| |
| if (m->err) { |
| cell_error(m->cell); |
| goto out; |
| } |
| |
| /* |
| * Commit the prepared block into the mapping btree. |
| * Any I/O for this block arriving after this point will get |
| * remapped to it directly. |
| */ |
| r = dm_thin_insert_block(tc->td, m->virt_block, m->data_block); |
| if (r) { |
| DMERR("dm_thin_insert_block() failed"); |
| cell_error(m->cell); |
| goto out; |
| } |
| |
| /* |
| * Release any bios held while the block was being provisioned. |
| * If we are processing a write bio that completely covers the block, |
| * we already processed it so can ignore it now when processing |
| * the bios in the cell. |
| */ |
| if (bio) { |
| cell_defer_except(tc, m->cell); |
| bio_endio(bio, 0); |
| } else |
| cell_defer(tc, m->cell, m->data_block); |
| |
| out: |
| list_del(&m->list); |
| mempool_free(m, tc->pool->mapping_pool); |
| } |
| |
| static void process_prepared_discard(struct dm_thin_new_mapping *m) |
| { |
| int r; |
| struct thin_c *tc = m->tc; |
| |
| r = dm_thin_remove_block(tc->td, m->virt_block); |
| if (r) |
| DMERR("dm_thin_remove_block() failed"); |
| |
| /* |
| * Pass the discard down to the underlying device? |
| */ |
| if (m->pass_discard) |
| remap_and_issue(tc, m->bio, m->data_block); |
| else |
| bio_endio(m->bio, 0); |
| |
| cell_defer_except(tc, m->cell); |
| cell_defer_except(tc, m->cell2); |
| mempool_free(m, tc->pool->mapping_pool); |
| } |
| |
| static void process_prepared(struct pool *pool, struct list_head *head, |
| void (*fn)(struct dm_thin_new_mapping *)) |
| { |
| unsigned long flags; |
| struct list_head maps; |
| struct dm_thin_new_mapping *m, *tmp; |
| |
| INIT_LIST_HEAD(&maps); |
| spin_lock_irqsave(&pool->lock, flags); |
| list_splice_init(head, &maps); |
| spin_unlock_irqrestore(&pool->lock, flags); |
| |
| list_for_each_entry_safe(m, tmp, &maps, list) |
| fn(m); |
| } |
| |
| /* |
| * Deferred bio jobs. |
| */ |
| static int io_overlaps_block(struct pool *pool, struct bio *bio) |
| { |
| return bio->bi_size == (pool->sectors_per_block << SECTOR_SHIFT); |
| } |
| |
| static int io_overwrites_block(struct pool *pool, struct bio *bio) |
| { |
| return (bio_data_dir(bio) == WRITE) && |
| io_overlaps_block(pool, bio); |
| } |
| |
| static void save_and_set_endio(struct bio *bio, bio_end_io_t **save, |
| bio_end_io_t *fn) |
| { |
| *save = bio->bi_end_io; |
| bio->bi_end_io = fn; |
| } |
| |
| static int ensure_next_mapping(struct pool *pool) |
| { |
| if (pool->next_mapping) |
| return 0; |
| |
| pool->next_mapping = mempool_alloc(pool->mapping_pool, GFP_ATOMIC); |
| |
| return pool->next_mapping ? 0 : -ENOMEM; |
| } |
| |
| static struct dm_thin_new_mapping *get_next_mapping(struct pool *pool) |
| { |
| struct dm_thin_new_mapping *r = pool->next_mapping; |
| |
| BUG_ON(!pool->next_mapping); |
| |
| pool->next_mapping = NULL; |
| |
| return r; |
| } |
| |
| static void schedule_copy(struct thin_c *tc, dm_block_t virt_block, |
| struct dm_dev *origin, dm_block_t data_origin, |
| dm_block_t data_dest, |
| struct dm_bio_prison_cell *cell, struct bio *bio) |
| { |
| int r; |
| struct pool *pool = tc->pool; |
| struct dm_thin_new_mapping *m = get_next_mapping(pool); |
| |
| INIT_LIST_HEAD(&m->list); |
| m->quiesced = 0; |
| m->prepared = 0; |
| m->tc = tc; |
| m->virt_block = virt_block; |
| m->data_block = data_dest; |
| m->cell = cell; |
| m->err = 0; |
| m->bio = NULL; |
| |
| if (!ds_add_work(&pool->shared_read_ds, &m->list)) |
| m->quiesced = 1; |
| |
| /* |
| * IO to pool_dev remaps to the pool target's data_dev. |
| * |
| * If the whole block of data is being overwritten, we can issue the |
| * bio immediately. Otherwise we use kcopyd to clone the data first. |
| */ |
| if (io_overwrites_block(pool, bio)) { |
| struct dm_thin_endio_hook *h = dm_get_mapinfo(bio)->ptr; |
| |
| h->overwrite_mapping = m; |
| m->bio = bio; |
| save_and_set_endio(bio, &m->saved_bi_end_io, overwrite_endio); |
| remap_and_issue(tc, bio, data_dest); |
| } else { |
| struct dm_io_region from, to; |
| |
| from.bdev = origin->bdev; |
| from.sector = data_origin * pool->sectors_per_block; |
| from.count = pool->sectors_per_block; |
| |
| to.bdev = tc->pool_dev->bdev; |
| to.sector = data_dest * pool->sectors_per_block; |
| to.count = pool->sectors_per_block; |
| |
| r = dm_kcopyd_copy(pool->copier, &from, 1, &to, |
| 0, copy_complete, m); |
| if (r < 0) { |
| mempool_free(m, pool->mapping_pool); |
| DMERR("dm_kcopyd_copy() failed"); |
| cell_error(cell); |
| } |
| } |
| } |
| |
| static void schedule_internal_copy(struct thin_c *tc, dm_block_t virt_block, |
| dm_block_t data_origin, dm_block_t data_dest, |
| struct dm_bio_prison_cell *cell, struct bio *bio) |
| { |
| schedule_copy(tc, virt_block, tc->pool_dev, |
| data_origin, data_dest, cell, bio); |
| } |
| |
| static void schedule_external_copy(struct thin_c *tc, dm_block_t virt_block, |
| dm_block_t data_dest, |
| struct dm_bio_prison_cell *cell, struct bio *bio) |
| { |
| schedule_copy(tc, virt_block, tc->origin_dev, |
| virt_block, data_dest, cell, bio); |
| } |
| |
| static void schedule_zero(struct thin_c *tc, dm_block_t virt_block, |
| dm_block_t data_block, struct dm_bio_prison_cell *cell, |
| struct bio *bio) |
| { |
| struct pool *pool = tc->pool; |
| struct dm_thin_new_mapping *m = get_next_mapping(pool); |
| |
| INIT_LIST_HEAD(&m->list); |
| m->quiesced = 1; |
| m->prepared = 0; |
| m->tc = tc; |
| m->virt_block = virt_block; |
| m->data_block = data_block; |
| m->cell = cell; |
| m->err = 0; |
| m->bio = NULL; |
| |
| /* |
| * If the whole block of data is being overwritten or we are not |
| * zeroing pre-existing data, we can issue the bio immediately. |
| * Otherwise we use kcopyd to zero the data first. |
| */ |
| if (!pool->pf.zero_new_blocks) |
| process_prepared_mapping(m); |
| |
| else if (io_overwrites_block(pool, bio)) { |
| struct dm_thin_endio_hook *h = dm_get_mapinfo(bio)->ptr; |
| |
| h->overwrite_mapping = m; |
| m->bio = bio; |
| save_and_set_endio(bio, &m->saved_bi_end_io, overwrite_endio); |
| remap_and_issue(tc, bio, data_block); |
| } else { |
| int r; |
| struct dm_io_region to; |
| |
| to.bdev = tc->pool_dev->bdev; |
| to.sector = data_block * pool->sectors_per_block; |
| to.count = pool->sectors_per_block; |
| |
| r = dm_kcopyd_zero(pool->copier, 1, &to, 0, copy_complete, m); |
| if (r < 0) { |
| mempool_free(m, pool->mapping_pool); |
| DMERR("dm_kcopyd_zero() failed"); |
| cell_error(cell); |
| } |
| } |
| } |
| |
| static int alloc_data_block(struct thin_c *tc, dm_block_t *result) |
| { |
| int r; |
| dm_block_t free_blocks; |
| unsigned long flags; |
| struct pool *pool = tc->pool; |
| |
| r = dm_pool_get_free_block_count(pool->pmd, &free_blocks); |
| if (r) |
| return r; |
| |
| if (free_blocks <= pool->low_water_blocks && !pool->low_water_triggered) { |
| DMWARN("%s: reached low water mark, sending event.", |
| dm_device_name(pool->pool_md)); |
| spin_lock_irqsave(&pool->lock, flags); |
| pool->low_water_triggered = 1; |
| spin_unlock_irqrestore(&pool->lock, flags); |
| dm_table_event(pool->ti->table); |
| } |
| |
| if (!free_blocks) { |
| if (pool->no_free_space) |
| return -ENOSPC; |
| else { |
| /* |
| * Try to commit to see if that will free up some |
| * more space. |
| */ |
| r = dm_pool_commit_metadata(pool->pmd); |
| if (r) { |
| DMERR("%s: dm_pool_commit_metadata() failed, error = %d", |
| __func__, r); |
| return r; |
| } |
| |
| r = dm_pool_get_free_block_count(pool->pmd, &free_blocks); |
| if (r) |
| return r; |
| |
| /* |
| * If we still have no space we set a flag to avoid |
| * doing all this checking and return -ENOSPC. |
| */ |
| if (!free_blocks) { |
| DMWARN("%s: no free space available.", |
| dm_device_name(pool->pool_md)); |
| spin_lock_irqsave(&pool->lock, flags); |
| pool->no_free_space = 1; |
| spin_unlock_irqrestore(&pool->lock, flags); |
| return -ENOSPC; |
| } |
| } |
| } |
| |
| r = dm_pool_alloc_data_block(pool->pmd, result); |
| if (r) |
| return r; |
| |
| return 0; |
| } |
| |
| /* |
| * If we have run out of space, queue bios until the device is |
| * resumed, presumably after having been reloaded with more space. |
| */ |
| static void retry_on_resume(struct bio *bio) |
| { |
| struct dm_thin_endio_hook *h = dm_get_mapinfo(bio)->ptr; |
| 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); |
| } |
| |
| static void no_space(struct dm_bio_prison_cell *cell) |
| { |
| struct bio *bio; |
| struct bio_list bios; |
| |
| bio_list_init(&bios); |
| cell_release(cell, &bios); |
| |
| while ((bio = bio_list_pop(&bios))) |
| retry_on_resume(bio); |
| } |
| |
| static void process_discard(struct thin_c *tc, struct bio *bio) |
| { |
| int r; |
| unsigned long flags; |
| struct pool *pool = tc->pool; |
| struct dm_bio_prison_cell *cell, *cell2; |
| struct cell_key key, key2; |
| dm_block_t block = get_bio_block(tc, bio); |
| struct dm_thin_lookup_result lookup_result; |
| struct dm_thin_new_mapping *m; |
| |
| build_virtual_key(tc->td, block, &key); |
| if (bio_detain(tc->pool->prison, &key, bio, &cell)) |
| return; |
| |
| r = dm_thin_find_block(tc->td, block, 1, &lookup_result); |
| switch (r) { |
| case 0: |
| /* |
| * Check nobody is fiddling with this pool block. This can |
| * happen if someone's in the process of breaking sharing |
| * on this block. |
| */ |
| build_data_key(tc->td, lookup_result.block, &key2); |
| if (bio_detain(tc->pool->prison, &key2, bio, &cell2)) { |
| cell_release_singleton(cell, bio); |
| break; |
| } |
| |
| if (io_overlaps_block(pool, bio)) { |
| /* |
| * IO may still be going to the destination block. We must |
| * quiesce before we can do the removal. |
| */ |
| m = get_next_mapping(pool); |
| m->tc = tc; |
| m->pass_discard = (!lookup_result.shared) && pool->pf.discard_passdown; |
| m->virt_block = block; |
| m->data_block = lookup_result.block; |
| m->cell = cell; |
| m->cell2 = cell2; |
| m->err = 0; |
| m->bio = bio; |
| |
| if (!ds_add_work(&pool->all_io_ds, &m->list)) { |
| spin_lock_irqsave(&pool->lock, flags); |
| list_add(&m->list, &pool->prepared_discards); |
| spin_unlock_irqrestore(&pool->lock, flags); |
| wake_worker(pool); |
| } |
| } else { |
| /* |
| * The DM core makes sure that the discard doesn't span |
| * a block boundary. So we submit the discard of a |
| * partial block appropriately. |
| */ |
| cell_release_singleton(cell, bio); |
| cell_release_singleton(cell2, bio); |
| if ((!lookup_result.shared) && pool->pf.discard_passdown) |
| remap_and_issue(tc, bio, lookup_result.block); |
| else |
| bio_endio(bio, 0); |
| } |
| break; |
| |
| case -ENODATA: |
| /* |
| * It isn't provisioned, just forget it. |
| */ |
| cell_release_singleton(cell, bio); |
| bio_endio(bio, 0); |
| break; |
| |
| default: |
| DMERR("discard: find block unexpectedly returned %d", r); |
| cell_release_singleton(cell, bio); |
| bio_io_error(bio); |
| break; |
| } |
| } |
| |
| static void break_sharing(struct thin_c *tc, struct bio *bio, dm_block_t block, |
| struct cell_key *key, |
| struct dm_thin_lookup_result *lookup_result, |
| struct dm_bio_prison_cell *cell) |
| { |
| int r; |
| dm_block_t data_block; |
| |
| r = alloc_data_block(tc, &data_block); |
| switch (r) { |
| case 0: |
| schedule_internal_copy(tc, block, lookup_result->block, |
| data_block, cell, bio); |
| break; |
| |
| case -ENOSPC: |
| no_space(cell); |
| break; |
| |
| default: |
| DMERR("%s: alloc_data_block() failed, error = %d", __func__, r); |
| cell_error(cell); |
| break; |
| } |
| } |
| |
| static void process_shared_bio(struct thin_c *tc, struct bio *bio, |
| dm_block_t block, |
| struct dm_thin_lookup_result *lookup_result) |
| { |
| struct dm_bio_prison_cell *cell; |
| struct pool *pool = tc->pool; |
| struct cell_key key; |
| |
| /* |
| * If cell is already occupied, then sharing is already in the process |
| * of being broken so we have nothing further to do here. |
| */ |
| build_data_key(tc->td, lookup_result->block, &key); |
| if (bio_detain(pool->prison, &key, bio, &cell)) |
| return; |
| |
| if (bio_data_dir(bio) == WRITE && bio->bi_size) |
| break_sharing(tc, bio, block, &key, lookup_result, cell); |
| else { |
| struct dm_thin_endio_hook *h = dm_get_mapinfo(bio)->ptr; |
| |
| h->shared_read_entry = ds_inc(&pool->shared_read_ds); |
| |
| cell_release_singleton(cell, bio); |
| remap_and_issue(tc, bio, lookup_result->block); |
| } |
| } |
| |
| static void provision_block(struct thin_c *tc, struct bio *bio, dm_block_t block, |
| struct dm_bio_prison_cell *cell) |
| { |
| int r; |
| dm_block_t data_block; |
| |
| /* |
| * Remap empty bios (flushes) immediately, without provisioning. |
| */ |
| if (!bio->bi_size) { |
| cell_release_singleton(cell, bio); |
| remap_and_issue(tc, bio, 0); |
| return; |
| } |
| |
| /* |
| * Fill read bios with zeroes and complete them immediately. |
| */ |
| if (bio_data_dir(bio) == READ) { |
| zero_fill_bio(bio); |
| cell_release_singleton(cell, bio); |
| bio_endio(bio, 0); |
| return; |
| } |
| |
| r = alloc_data_block(tc, &data_block); |
| switch (r) { |
| case 0: |
| if (tc->origin_dev) |
| schedule_external_copy(tc, block, data_block, cell, bio); |
| else |
| schedule_zero(tc, block, data_block, cell, bio); |
| break; |
| |
| case -ENOSPC: |
| no_space(cell); |
| break; |
| |
| default: |
| DMERR("%s: alloc_data_block() failed, error = %d", __func__, r); |
| cell_error(cell); |
| break; |
| } |
| } |
| |
| static void process_bio(struct thin_c *tc, struct bio *bio) |
| { |
| int r; |
| dm_block_t block = get_bio_block(tc, bio); |
| struct dm_bio_prison_cell *cell; |
| struct cell_key key; |
| struct dm_thin_lookup_result lookup_result; |
| |
| /* |
| * If cell is already occupied, then the block is already |
| * being provisioned so we have nothing further to do here. |
| */ |
| build_virtual_key(tc->td, block, &key); |
| if (bio_detain(tc->pool->prison, &key, bio, &cell)) |
| return; |
| |
| r = dm_thin_find_block(tc->td, block, 1, &lookup_result); |
| switch (r) { |
| case 0: |
| /* |
| * We can release this cell now. This thread is the only |
| * one that puts bios into a cell, and we know there were |
| * no preceding bios. |
| */ |
| /* |
| * TODO: this will probably have to change when discard goes |
| * back in. |
| */ |
| cell_release_singleton(cell, bio); |
| |
| if (lookup_result.shared) |
| process_shared_bio(tc, bio, block, &lookup_result); |
| else |
| remap_and_issue(tc, bio, lookup_result.block); |
| break; |
| |
| case -ENODATA: |
| if (bio_data_dir(bio) == READ && tc->origin_dev) { |
| cell_release_singleton(cell, bio); |
| remap_to_origin_and_issue(tc, bio); |
| } else |
| provision_block(tc, bio, block, cell); |
| break; |
| |
| default: |
| DMERR("dm_thin_find_block() failed, error = %d", r); |
| cell_release_singleton(cell, bio); |
| bio_io_error(bio); |
| break; |
| } |
| } |
| |
| static int need_commit_due_to_time(struct pool *pool) |
| { |
| return jiffies < pool->last_commit_jiffies || |
| jiffies > pool->last_commit_jiffies + COMMIT_PERIOD; |
| } |
| |
| static void process_deferred_bios(struct pool *pool) |
| { |
| unsigned long flags; |
| struct bio *bio; |
| struct bio_list bios; |
| int r; |
| |
| 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); |
| |
| while ((bio = bio_list_pop(&bios))) { |
| struct dm_thin_endio_hook *h = dm_get_mapinfo(bio)->ptr; |
| struct thin_c *tc = h->tc; |
| |
| /* |
| * 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); |
| |
| break; |
| } |
| |
| if (bio->bi_rw & REQ_DISCARD) |
| process_discard(tc, bio); |
| else |
| process_bio(tc, bio); |
| } |
| |
| /* |
| * If there are any deferred flush bios, we must commit |
| * the metadata before issuing them. |
| */ |
| bio_list_init(&bios); |
| spin_lock_irqsave(&pool->lock, flags); |
| bio_list_merge(&bios, &pool->deferred_flush_bios); |
| bio_list_init(&pool->deferred_flush_bios); |
| spin_unlock_irqrestore(&pool->lock, flags); |
| |
| if (bio_list_empty(&bios) && !need_commit_due_to_time(pool)) |
| return; |
| |
| r = dm_pool_commit_metadata(pool->pmd); |
| if (r) { |
| DMERR("%s: dm_pool_commit_metadata() failed, error = %d", |
| __func__, r); |
| while ((bio = bio_list_pop(&bios))) |
| bio_io_error(bio); |
| return; |
| } |
| pool->last_commit_jiffies = jiffies; |
| |
| while ((bio = bio_list_pop(&bios))) |
| generic_make_request(bio); |
| } |
| |
| static void do_worker(struct work_struct *ws) |
| { |
| struct pool *pool = container_of(ws, struct pool, worker); |
| |
| process_prepared(pool, &pool->prepared_mappings, process_prepared_mapping); |
| process_prepared(pool, &pool->prepared_discards, process_prepared_discard); |
| process_deferred_bios(pool); |
| } |
| |
| /* |
| * We want to commit periodically so that not too much |
| * unwritten data builds up. |
| */ |
| static void do_waker(struct work_struct *ws) |
| { |
| struct pool *pool = container_of(to_delayed_work(ws), struct pool, waker); |
| wake_worker(pool); |
| queue_delayed_work(pool->wq, &pool->waker, COMMIT_PERIOD); |
| } |
| |
| /*----------------------------------------------------------------*/ |
| |
| /* |
| * Mapping functions. |
| */ |
| |
| /* |
| * Called only while mapping a thin bio to hand it over to the workqueue. |
| */ |
| static void thin_defer_bio(struct thin_c *tc, struct bio *bio) |
| { |
| 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); |
| |
| wake_worker(pool); |
| } |
| |
| static struct dm_thin_endio_hook *thin_hook_bio(struct thin_c *tc, struct bio *bio) |
| { |
| struct pool *pool = tc->pool; |
| struct dm_thin_endio_hook *h = mempool_alloc(pool->endio_hook_pool, GFP_NOIO); |
| |
| h->tc = tc; |
| h->shared_read_entry = NULL; |
| h->all_io_entry = bio->bi_rw & REQ_DISCARD ? NULL : ds_inc(&pool->all_io_ds); |
| h->overwrite_mapping = NULL; |
| |
| return h; |
| } |
| |
| /* |
| * Non-blocking function called from the thin target's map function. |
| */ |
| static int thin_bio_map(struct dm_target *ti, struct bio *bio, |
| union map_info *map_context) |
| { |
| int r; |
| struct thin_c *tc = ti->private; |
| dm_block_t block = get_bio_block(tc, bio); |
| struct dm_thin_device *td = tc->td; |
| struct dm_thin_lookup_result result; |
| |
| map_context->ptr = thin_hook_bio(tc, bio); |
| if (bio->bi_rw & (REQ_DISCARD | REQ_FLUSH | REQ_FUA)) { |
| thin_defer_bio(tc, bio); |
| return DM_MAPIO_SUBMITTED; |
| } |
| |
| r = dm_thin_find_block(td, block, 0, &result); |
| |
| /* |
| * Note that we defer readahead too. |
| */ |
| switch (r) { |
| case 0: |
| if (unlikely(result.shared)) { |
| /* |
| * We have a race condition here between the |
| * result.shared value returned by the lookup and |
| * snapshot creation, which may cause new |
| * sharing. |
| * |
| * To avoid this always quiesce the origin before |
| * taking the snap. You want to do this anyway to |
| * ensure a consistent application view |
| * (i.e. lockfs). |
| * |
| * More distant ancestors are irrelevant. The |
| * shared flag will be set in their case. |
| */ |
| thin_defer_bio(tc, bio); |
| r = DM_MAPIO_SUBMITTED; |
| } else { |
| remap(tc, bio, result.block); |
| r = DM_MAPIO_REMAPPED; |
| } |
| break; |
| |
| case -ENODATA: |
| /* |
| * In future, the failed dm_thin_find_block above could |
| * provide the hint to load the metadata into cache. |
| */ |
| case -EWOULDBLOCK: |
| thin_defer_bio(tc, bio); |
| r = DM_MAPIO_SUBMITTED; |
| break; |
| } |
| |
| return r; |
| } |
| |
| 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); |
| |
| 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 (!r) { |
| struct request_queue *q = bdev_get_queue(pt->data_dev->bdev); |
| r = bdi_congested(&q->backing_dev_info, bdi_bits); |
| } |
| |
| return r; |
| } |
| |
| 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); |
| } |
| |
| /*---------------------------------------------------------------- |
| * Binding of control targets to a pool object |
| *--------------------------------------------------------------*/ |
| static int bind_control_target(struct pool *pool, struct dm_target *ti) |
| { |
| struct pool_c *pt = ti->private; |
| |
| pool->ti = ti; |
| pool->low_water_blocks = pt->low_water_blocks; |
| pool->pf = pt->pf; |
| |
| /* |
| * If discard_passdown was enabled verify that the data device |
| * supports discards. Disable discard_passdown if not; otherwise |
| * -EOPNOTSUPP will be returned. |
| */ |
| if (pt->pf.discard_passdown) { |
| struct request_queue *q = bdev_get_queue(pt->data_dev->bdev); |
| if (!q || !blk_queue_discard(q)) { |
| char buf[BDEVNAME_SIZE]; |
| DMWARN("Discard unsupported by data device (%s): Disabling discard passdown.", |
| bdevname(pt->data_dev->bdev, buf)); |
| pool->pf.discard_passdown = 0; |
| } |
| } |
| |
| return 0; |
| } |
| |
| static void unbind_control_target(struct pool *pool, struct dm_target *ti) |
| { |
| if (pool->ti == ti) |
| pool->ti = NULL; |
| } |
| |
| /*---------------------------------------------------------------- |
| * Pool creation |
| *--------------------------------------------------------------*/ |
| /* Initialize pool features. */ |
| static void pool_features_init(struct pool_features *pf) |
| { |
| pf->zero_new_blocks = 1; |
| pf->discard_enabled = 1; |
| pf->discard_passdown = 1; |
| } |
| |
| static void __pool_destroy(struct pool *pool) |
| { |
| __pool_table_remove(pool); |
| |
| if (dm_pool_metadata_close(pool->pmd) < 0) |
| DMWARN("%s: dm_pool_metadata_close() failed.", __func__); |
| |
| prison_destroy(pool->prison); |
| dm_kcopyd_client_destroy(pool->copier); |
| |
| if (pool->wq) |
| destroy_workqueue(pool->wq); |
| |
| if (pool->next_mapping) |
| mempool_free(pool->next_mapping, pool->mapping_pool); |
| mempool_destroy(pool->mapping_pool); |
| mempool_destroy(pool->endio_hook_pool); |
| kfree(pool); |
| } |
| |
| static struct kmem_cache *_new_mapping_cache; |
| static struct kmem_cache *_endio_hook_cache; |
| |
| static struct pool *pool_create(struct mapped_device *pool_md, |
| struct block_device *metadata_dev, |
| unsigned long block_size, char **error) |
| { |
| int r; |
| void *err_p; |
| struct pool *pool; |
| struct dm_pool_metadata *pmd; |
| |
| pmd = dm_pool_metadata_open(metadata_dev, block_size, true); |
| if (IS_ERR(pmd)) { |
| *error = "Error creating metadata object"; |
| return (struct pool *)pmd; |
| } |
| |
| pool = kmalloc(sizeof(*pool), GFP_KERNEL); |
| if (!pool) { |
| *error = "Error allocating memory for pool"; |
| err_p = ERR_PTR(-ENOMEM); |
| goto bad_pool; |
| } |
| |
| pool->pmd = pmd; |
| pool->sectors_per_block = block_size; |
| if (block_size & (block_size - 1)) |
| pool->sectors_per_block_shift = -1; |
| else |
| pool->sectors_per_block_shift = __ffs(block_size); |
| pool->low_water_blocks = 0; |
| pool_features_init(&pool->pf); |
| pool->prison = prison_create(PRISON_CELLS); |
| if (!pool->prison) { |
| *error = "Error creating pool's bio prison"; |
| err_p = ERR_PTR(-ENOMEM); |
| goto bad_prison; |
| } |
| |
| pool->copier = dm_kcopyd_client_create(); |
| if (IS_ERR(pool->copier)) { |
| r = PTR_ERR(pool->copier); |
| *error = "Error creating pool's kcopyd client"; |
| err_p = ERR_PTR(r); |
| goto bad_kcopyd_client; |
| } |
| |
| /* |
| * Create singlethreaded workqueue that will service all devices |
| * that use this metadata. |
| */ |
| pool->wq = alloc_ordered_workqueue("dm-" DM_MSG_PREFIX, WQ_MEM_RECLAIM); |
| if (!pool->wq) { |
| *error = "Error creating pool's workqueue"; |
| err_p = ERR_PTR(-ENOMEM); |
| goto bad_wq; |
| } |
| |
| 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); |
| pool->low_water_triggered = 0; |
| pool->no_free_space = 0; |
| bio_list_init(&pool->retry_on_resume_list); |
| ds_init(&pool->shared_read_ds); |
| ds_init(&pool->all_io_ds); |
| |
| pool->next_mapping = NULL; |
| pool->mapping_pool = mempool_create_slab_pool(MAPPING_POOL_SIZE, |
| _new_mapping_cache); |
| if (!pool->mapping_pool) { |
| *error = "Error creating pool's mapping mempool"; |
| err_p = ERR_PTR(-ENOMEM); |
| goto bad_mapping_pool; |
| } |
| |
| pool->endio_hook_pool = mempool_create_slab_pool(ENDIO_HOOK_POOL_SIZE, |
| _endio_hook_cache); |
| if (!pool->endio_hook_pool) { |
| *error = "Error creating pool's endio_hook mempool"; |
| err_p = ERR_PTR(-ENOMEM); |
| goto bad_endio_hook_pool; |
| } |
| pool->ref_count = 1; |
| pool->last_commit_jiffies = jiffies; |
| pool->pool_md = pool_md; |
| pool->md_dev = metadata_dev; |
| __pool_table_insert(pool); |
| |
| return pool; |
| |
| bad_endio_hook_pool: |
| mempool_destroy(pool->mapping_pool); |
| bad_mapping_pool: |
| destroy_workqueue(pool->wq); |
| bad_wq: |
| dm_kcopyd_client_destroy(pool->copier); |
| bad_kcopyd_client: |
| prison_destroy(pool->prison); |
| bad_prison: |
| kfree(pool); |
| bad_pool: |
| if (dm_pool_metadata_close(pmd)) |
| DMWARN("%s: dm_pool_metadata_close() failed.", __func__); |
| |
| return err_p; |
| } |
| |
| static void __pool_inc(struct pool *pool) |
| { |
| BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex)); |
| pool->ref_count++; |
| } |
| |
| static void __pool_dec(struct pool *pool) |
| { |
| BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex)); |
| BUG_ON(!pool->ref_count); |
| if (!--pool->ref_count) |
| __pool_destroy(pool); |
| } |
| |
| static struct pool *__pool_find(struct mapped_device *pool_md, |
| struct block_device *metadata_dev, |
| unsigned long block_size, char **error, |
| int *created) |
| { |
| struct pool *pool = __pool_table_lookup_metadata_dev(metadata_dev); |
| |
| if (pool) { |
| if (pool->pool_md != pool_md) { |
| *error = "metadata device already in use by a pool"; |
| return ERR_PTR(-EBUSY); |
| } |
| __pool_inc(pool); |
| |
| } else { |
| pool = __pool_table_lookup(pool_md); |
| if (pool) { |
| if (pool->md_dev != metadata_dev) { |
| *error = "different pool cannot replace a pool"; |
| return ERR_PTR(-EINVAL); |
| } |
| __pool_inc(pool); |
| |
| } else { |
| pool = pool_create(pool_md, metadata_dev, block_size, error); |
| *created = 1; |
| } |
| } |
| |
| return pool; |
| } |
| |
| /*---------------------------------------------------------------- |
| * Pool target methods |
| *--------------------------------------------------------------*/ |
| static void pool_dtr(struct dm_target *ti) |
| { |
| struct pool_c *pt = ti->private; |
| |
| mutex_lock(&dm_thin_pool_table.mutex); |
| |
| unbind_control_target(pt->pool, ti); |
| __pool_dec(pt->pool); |
| dm_put_device(ti, pt->metadata_dev); |
| dm_put_device(ti, pt->data_dev); |
| kfree(pt); |
| |
| mutex_unlock(&dm_thin_pool_table.mutex); |
| } |
| |
| static int parse_pool_features(struct dm_arg_set *as, struct pool_features *pf, |
| struct dm_target *ti) |
| { |
| int r; |
| unsigned argc; |
| const char *arg_name; |
| |
| static struct dm_arg _args[] = { |
| {0, 3, "Invalid number of pool feature arguments"}, |
| }; |
| |
| /* |
| * No feature arguments supplied. |
| */ |
| if (!as->argc) |
| return 0; |
| |
| r = dm_read_arg_group(_args, as, &argc, &ti->error); |
| if (r) |
| return -EINVAL; |
| |
| while (argc && !r) { |
| arg_name = dm_shift_arg(as); |
| argc--; |
| |
| if (!strcasecmp(arg_name, "skip_block_zeroing")) { |
| pf->zero_new_blocks = 0; |
| continue; |
| } else if (!strcasecmp(arg_name, "ignore_discard")) { |
| pf->discard_enabled = 0; |
| continue; |
| } else if (!strcasecmp(arg_name, "no_discard_passdown")) { |
| pf->discard_passdown = 0; |
| continue; |
| } |
| |
| ti->error = "Unrecognised pool feature requested"; |
| r = -EINVAL; |
| } |
| |
| return r; |
| } |
| |
| /* |
| * thin-pool <metadata dev> <data dev> |
| * <data block size (sectors)> |
| * <low water mark (blocks)> |
| * [<#feature args> [<arg>]*] |
| * |
| * Optional feature arguments are: |
| * skip_block_zeroing: skips the zeroing of newly-provisioned blocks. |
| * ignore_discard: disable discard |
| * no_discard_passdown: don't pass discards down to the data device |
| */ |
| static int pool_ctr(struct dm_target *ti, unsigned argc, char **argv) |
| { |
| int r, pool_created = 0; |
| struct pool_c *pt; |
| struct pool *pool; |
| struct pool_features pf; |
| struct dm_arg_set as; |
| struct dm_dev *data_dev; |
| unsigned long block_size; |
| dm_block_t low_water_blocks; |
| struct dm_dev *metadata_dev; |
| sector_t metadata_dev_size; |
| char b[BDEVNAME_SIZE]; |
| |
| /* |
| * FIXME Remove validation from scope of lock. |
| */ |
| mutex_lock(&dm_thin_pool_table.mutex); |
| |
| if (argc < 4) { |
| ti->error = "Invalid argument count"; |
| r = -EINVAL; |
| goto out_unlock; |
| } |
| as.argc = argc; |
| as.argv = argv; |
| |
| r = dm_get_device(ti, argv[0], FMODE_READ | FMODE_WRITE, &metadata_dev); |
| if (r) { |
| ti->error = "Error opening metadata block device"; |
| goto out_unlock; |
| } |
| |
| metadata_dev_size = i_size_read(metadata_dev->bdev->bd_inode) >> SECTOR_SHIFT; |
| if (metadata_dev_size > THIN_METADATA_MAX_SECTORS_WARNING) |
| DMWARN("Metadata device %s is larger than %u sectors: excess space will not be used.", |
| bdevname(metadata_dev->bdev, b), THIN_METADATA_MAX_SECTORS); |
| |
| r = dm_get_device(ti, argv[1], FMODE_READ | FMODE_WRITE, &data_dev); |
| if (r) { |
| ti->error = "Error getting data device"; |
| goto out_metadata; |
| } |
| |
| if (kstrtoul(argv[2], 10, &block_size) || !block_size || |
| block_size < DATA_DEV_BLOCK_SIZE_MIN_SECTORS || |
| block_size > DATA_DEV_BLOCK_SIZE_MAX_SECTORS || |
| block_size & (DATA_DEV_BLOCK_SIZE_MIN_SECTORS - 1)) { |
| ti->error = "Invalid block size"; |
| r = -EINVAL; |
| goto out; |
| } |
| |
| if (kstrtoull(argv[3], 10, (unsigned long long *)&low_water_blocks)) { |
| ti->error = "Invalid low water mark"; |
| r = -EINVAL; |
| goto out; |
| } |
| |
| /* |
| * Set default pool features. |
| */ |
| pool_features_init(&pf); |
| |
| dm_consume_args(&as, 4); |
| r = parse_pool_features(&as, &pf, ti); |
| if (r) |
| goto out; |
| |
| pt = kzalloc(sizeof(*pt), GFP_KERNEL); |
| if (!pt) { |
| r = -ENOMEM; |
| goto out; |
| } |
| |
| pool = __pool_find(dm_table_get_md(ti->table), metadata_dev->bdev, |
| block_size, &ti->error, &pool_created); |
| if (IS_ERR(pool)) { |
| r = PTR_ERR(pool); |
| goto out_free_pt; |
| } |
| |
| /* |
| * 'pool_created' reflects whether this is the first table load. |
| * Top level discard support is not allowed to be changed after |
| * initial load. This would require a pool reload to trigger thin |
| * device changes. |
| */ |
| if (!pool_created && pf.discard_enabled != pool->pf.discard_enabled) { |
| ti->error = "Discard support cannot be disabled once enabled"; |
| r = -EINVAL; |
| goto out_flags_changed; |
| } |
| |
| /* |
| * The block layer requires discard_granularity to be a power of 2. |
| */ |
| if (pf.discard_enabled && !is_power_of_2(block_size)) { |
| ti->error = "Discard support must be disabled when the block size is not a power of 2"; |
| r = -EINVAL; |
| goto out_flags_changed; |
| } |
| |
| pt->pool = pool; |
| pt->ti = ti; |
| pt->metadata_dev = metadata_dev; |
| pt->data_dev = data_dev; |
| pt->low_water_blocks = low_water_blocks; |
| pt->pf = pf; |
| ti->num_flush_requests = 1; |
| /* |
| * Only need to enable discards if the pool should pass |
| * them down to the data device. The thin device's discard |
| * processing will cause mappings to be removed from the btree. |
| */ |
| if (pf.discard_enabled && pf.discard_passdown) { |
| ti->num_discard_requests = 1; |
| /* |
| * Setting 'discards_supported' circumvents the normal |
| * stacking of discard limits (this keeps the pool and |
| * thin devices' discard limits consistent). |
| */ |
| ti->discards_supported = true; |
| } |
| ti->private = pt; |
| |
| pt->callbacks.congested_fn = pool_is_congested; |
| dm_table_add_target_callbacks(ti->table, &pt->callbacks); |
| |
| mutex_unlock(&dm_thin_pool_table.mutex); |
| |
| return 0; |
| |
| out_flags_changed: |
| __pool_dec(pool); |
| out_free_pt: |
| kfree(pt); |
| out: |
| dm_put_device(ti, data_dev); |
| out_metadata: |
| dm_put_device(ti, metadata_dev); |
| out_unlock: |
| mutex_unlock(&dm_thin_pool_table.mutex); |
| |
| return r; |
| } |
| |
| static int pool_map(struct dm_target *ti, struct bio *bio, |
| union map_info *map_context) |
| { |
| int r; |
| struct pool_c *pt = ti->private; |
| struct pool *pool = pt->pool; |
| unsigned long flags; |
| |
| /* |
| * As this is a singleton target, ti->begin is always zero. |
| */ |
| spin_lock_irqsave(&pool->lock, flags); |
| bio->bi_bdev = pt->data_dev->bdev; |
| r = DM_MAPIO_REMAPPED; |
| spin_unlock_irqrestore(&pool->lock, flags); |
| |
| return r; |
| } |
| |
| /* |
| * Retrieves the number of blocks of the data device from |
| * the superblock and compares it to the actual device size, |
| * thus resizing the data device in case it has grown. |
| * |
| * This both copes with opening preallocated data devices in the ctr |
| * being followed by a resume |
| * -and- |
| * calling the resume method individually after userspace has |
| * grown the data device in reaction to a table event. |
| */ |
| static int pool_preresume(struct dm_target *ti) |
| { |
| int r; |
| struct pool_c *pt = ti->private; |
| struct pool *pool = pt->pool; |
| sector_t data_size = ti->len; |
| dm_block_t sb_data_size; |
| |
| /* |
| * Take control of the pool object. |
| */ |
| r = bind_control_target(pool, ti); |
| if (r) |
| return r; |
| |
| (void) sector_div(data_size, pool->sectors_per_block); |
| |
| r = dm_pool_get_data_dev_size(pool->pmd, &sb_data_size); |
| if (r) { |
| DMERR("failed to retrieve data device size"); |
| return r; |
| } |
| |
| if (data_size < sb_data_size) { |
| DMERR("pool target too small, is %llu blocks (expected %llu)", |
| (unsigned long long)data_size, sb_data_size); |
| return -EINVAL; |
| |
| } else if (data_size > sb_data_size) { |
| r = dm_pool_resize_data_dev(pool->pmd, data_size); |
| if (r) { |
| DMERR("failed to resize data device"); |
| return r; |
| } |
| |
| r = dm_pool_commit_metadata(pool->pmd); |
| if (r) { |
| DMERR("%s: dm_pool_commit_metadata() failed, error = %d", |
| __func__, r); |
| return r; |
| } |
| } |
| |
| return 0; |
| } |
| |
| static void pool_resume(struct dm_target *ti) |
| { |
| struct pool_c *pt = ti->private; |
| struct pool *pool = pt->pool; |
| unsigned long flags; |
| |
| spin_lock_irqsave(&pool->lock, flags); |
| pool->low_water_triggered = 0; |
| pool->no_free_space = 0; |
| __requeue_bios(pool); |
| spin_unlock_irqrestore(&pool->lock, flags); |
| |
| do_waker(&pool->waker.work); |
| } |
| |
| static void pool_postsuspend(struct dm_target *ti) |
| { |
| int r; |
| struct pool_c *pt = ti->private; |
| struct pool *pool = pt->pool; |
| |
| cancel_delayed_work(&pool->waker); |
| flush_workqueue(pool->wq); |
| |
| r = dm_pool_commit_metadata(pool->pmd); |
| if (r < 0) { |
| DMERR("%s: dm_pool_commit_metadata() failed, error = %d", |
| __func__, r); |
| /* FIXME: invalidate device? error the next FUA or FLUSH bio ?*/ |
| } |
| } |
| |
| static int check_arg_count(unsigned argc, unsigned args_required) |
| { |
| if (argc != args_required) { |
| DMWARN("Message received with %u arguments instead of %u.", |
| argc, args_required); |
| return -EINVAL; |
| } |
| |
| return 0; |
| } |
| |
| static int read_dev_id(char *arg, dm_thin_id *dev_id, int warning) |
| { |
| if (!kstrtoull(arg, 10, (unsigned long long *)dev_id) && |
| *dev_id <= MAX_DEV_ID) |
| return 0; |
| |
| if (warning) |
| DMWARN("Message received with invalid device id: %s", arg); |
| |
| return -EINVAL; |
| } |
| |
| static int process_create_thin_mesg(unsigned argc, char **argv, struct pool *pool) |
| { |
| dm_thin_id dev_id; |
| int r; |
| |
| r = check_arg_count(argc, 2); |
| if (r) |
| return r; |
| |
| r = read_dev_id(argv[1], &dev_id, 1); |
| if (r) |
| return r; |
| |
| r = dm_pool_create_thin(pool->pmd, dev_id); |
| if (r) { |
| DMWARN("Creation of new thinly-provisioned device with id %s failed.", |
| argv[1]); |
| return r; |
| } |
| |
| return 0; |
| } |
| |
| static int process_create_snap_mesg(unsigned argc, char **argv, struct pool *pool) |
| { |
| dm_thin_id dev_id; |
| dm_thin_id origin_dev_id; |
| int r; |
| |
| r = check_arg_count(argc, 3); |
| if (r) |
| return r; |
| |
| r = read_dev_id(argv[1], &dev_id, 1); |
| if (r) |
| return r; |
| |
| r = read_dev_id(argv[2], &origin_dev_id, 1); |
| if (r) |
| return r; |
| |
| r = dm_pool_create_snap(pool->pmd, dev_id, origin_dev_id); |
| if (r) { |
| DMWARN("Creation of new snapshot %s of device %s failed.", |
| argv[1], argv[2]); |
| return r; |
| } |
| |
| return 0; |
| } |
| |
| static int process_delete_mesg(unsigned argc, char **argv, struct pool *pool) |
| { |
| dm_thin_id dev_id; |
| int r; |
| |
| r = check_arg_count(argc, 2); |
| if (r) |
| return r; |
| |
| r = read_dev_id(argv[1], &dev_id, 1); |
| if (r) |
| return r; |
| |
| r = dm_pool_delete_thin_device(pool->pmd, dev_id); |
| if (r) |
| DMWARN("Deletion of thin device %s failed.", argv[1]); |
| |
| return r; |
| } |
| |
| static int process_set_transaction_id_mesg(unsigned argc, char **argv, struct pool *pool) |
| { |
| dm_thin_id old_id, new_id; |
| int r; |
| |
| r = check_arg_count(argc, 3); |
| if (r) |
| return r; |
| |
| if (kstrtoull(argv[1], 10, (unsigned long long *)&old_id)) { |
| DMWARN("set_transaction_id message: Unrecognised id %s.", argv[1]); |
| return -EINVAL; |
| } |
| |
| if (kstrtoull(argv[2], 10, (unsigned long long *)&new_id)) { |
| DMWARN("set_transaction_id message: Unrecognised new id %s.", argv[2]); |
| return -EINVAL; |
| } |
| |
| r = dm_pool_set_metadata_transaction_id(pool->pmd, old_id, new_id); |
| if (r) { |
| DMWARN("Failed to change transaction id from %s to %s.", |
| argv[1], argv[2]); |
| return r; |
| } |
| |
| return 0; |
| } |
| |
| static int process_reserve_metadata_snap_mesg(unsigned argc, char **argv, struct pool *pool) |
| { |
| int r; |
| |
| r = check_arg_count(argc, 1); |
| if (r) |
| return r; |
| |
| r = dm_pool_commit_metadata(pool->pmd); |
| if (r) { |
| DMERR("%s: dm_pool_commit_metadata() failed, error = %d", |
| __func__, r); |
| return r; |
| } |
| |
| r = dm_pool_reserve_metadata_snap(pool->pmd); |
| if (r) |
| DMWARN("reserve_metadata_snap message failed."); |
| |
| return r; |
| } |
| |
| static int process_release_metadata_snap_mesg(unsigned argc, char **argv, struct pool *pool) |
| { |
| int r; |
| |
| r = check_arg_count(argc, 1); |
| if (r) |
| return r; |
| |
| r = dm_pool_release_metadata_snap(pool->pmd); |
| if (r) |
| DMWARN("release_metadata_snap message failed."); |
| |
| return r; |
| } |
| |
| /* |
| * Messages supported: |
| * create_thin <dev_id> |
| * create_snap <dev_id> <origin_id> |
| * delete <dev_id> |
| * trim <dev_id> <new_size_in_sectors> |
| * set_transaction_id <current_trans_id> <new_trans_id> |
| * reserve_metadata_snap |
| * release_metadata_snap |
| */ |
| static int pool_message(struct dm_target *ti, unsigned argc, char **argv) |
| { |
| int r = -EINVAL; |
| struct pool_c *pt = ti->private; |
| struct pool *pool = pt->pool; |
| |
| if (!strcasecmp(argv[0], "create_thin")) |
| r = process_create_thin_mesg(argc, argv, pool); |
| |
| else if (!strcasecmp(argv[0], "create_snap")) |
| r = process_create_snap_mesg(argc, argv, pool); |
| |
| else if (!strcasecmp(argv[0], "delete")) |
| r = process_delete_mesg(argc, argv, pool); |
| |
| else if (!strcasecmp(argv[0], "set_transaction_id")) |
| r = process_set_transaction_id_mesg(argc, argv, pool); |
| |
| else if (!strcasecmp(argv[0], "reserve_metadata_snap")) |
| r = process_reserve_metadata_snap_mesg(argc, argv, pool); |
| |
| else if (!strcasecmp(argv[0], "release_metadata_snap")) |
| r = process_release_metadata_snap_mesg(argc, argv, pool); |
| |
| else |
| DMWARN("Unrecognised thin pool target message received: %s", argv[0]); |
| |
| if (!r) { |
| r = dm_pool_commit_metadata(pool->pmd); |
| if (r) |
| DMERR("%s message: dm_pool_commit_metadata() failed, error = %d", |
| argv[0], r); |
| } |
| |
| return r; |
| } |
| |
| /* |
| * Status line is: |
| * <transaction id> <used metadata sectors>/<total metadata sectors> |
| * <used data sectors>/<total data sectors> <held metadata root> |
| */ |
| static int pool_status(struct dm_target *ti, status_type_t type, |
| char *result, unsigned maxlen) |
| { |
| int r, count; |
| unsigned sz = 0; |
| uint64_t transaction_id; |
| dm_block_t nr_free_blocks_data; |
| dm_block_t nr_free_blocks_metadata; |
| dm_block_t nr_blocks_data; |
| dm_block_t nr_blocks_metadata; |
| dm_block_t held_root; |
| char buf[BDEVNAME_SIZE]; |
| char buf2[BDEVNAME_SIZE]; |
| struct pool_c *pt = ti->private; |
| struct pool *pool = pt->pool; |
| |
| switch (type) { |
| case STATUSTYPE_INFO: |
| r = dm_pool_get_metadata_transaction_id(pool->pmd, |
| &transaction_id); |
| if (r) |
| return r; |
| |
| r = dm_pool_get_free_metadata_block_count(pool->pmd, |
| &nr_free_blocks_metadata); |
| if (r) |
| return r; |
| |
| r = dm_pool_get_metadata_dev_size(pool->pmd, &nr_blocks_metadata); |
| if (r) |
| return r; |
| |
| r = dm_pool_get_free_block_count(pool->pmd, |
| &nr_free_blocks_data); |
| if (r) |
| return r; |
| |
| r = dm_pool_get_data_dev_size(pool->pmd, &nr_blocks_data); |
| if (r) |
| return r; |
| |
| r = dm_pool_get_metadata_snap(pool->pmd, &held_root); |
| if (r) |
| return r; |
| |
| DMEMIT("%llu %llu/%llu %llu/%llu ", |
| (unsigned long long)transaction_id, |
| (unsigned long long)(nr_blocks_metadata - nr_free_blocks_metadata), |
| (unsigned long long)nr_blocks_metadata, |
| (unsigned long long)(nr_blocks_data - nr_free_blocks_data), |
| (unsigned long long)nr_blocks_data); |
| |
| if (held_root) |
| DMEMIT("%llu", held_root); |
| else |
| DMEMIT("-"); |
| |
| break; |
| |
| case STATUSTYPE_TABLE: |
| DMEMIT("%s %s %lu %llu ", |
| format_dev_t(buf, pt->metadata_dev->bdev->bd_dev), |
| format_dev_t(buf2, pt->data_dev->bdev->bd_dev), |
| (unsigned long)pool->sectors_per_block, |
| (unsigned long long)pt->low_water_blocks); |
| |
| count = !pool->pf.zero_new_blocks + !pool->pf.discard_enabled + |
| !pt->pf.discard_passdown; |
| DMEMIT("%u ", count); |
| |
| if (!pool->pf.zero_new_blocks) |
| DMEMIT("skip_block_zeroing "); |
| |
| if (!pool->pf.discard_enabled) |
| DMEMIT("ignore_discard "); |
| |
| if (!pt->pf.discard_passdown) |
| DMEMIT("no_discard_passdown "); |
| |
| break; |
| } |
| |
| return 0; |
| } |
| |
| static int pool_iterate_devices(struct dm_target *ti, |
| iterate_devices_callout_fn fn, void *data) |
| { |
| struct pool_c *pt = ti->private; |
| |
| return fn(ti, pt->data_dev, 0, ti->len, data); |
| } |
| |
| static int pool_merge(struct dm_target *ti, struct bvec_merge_data *bvm, |
| struct bio_vec *biovec, int max_size) |
| { |
| struct pool_c *pt = ti->private; |
| struct request_queue *q = bdev_get_queue(pt->data_dev->bdev); |
| |
| if (!q->merge_bvec_fn) |
| return max_size; |
| |
| bvm->bi_bdev = pt->data_dev->bdev; |
| |
| return min(max_size, q->merge_bvec_fn(q, bvm, biovec)); |
| } |
| |
| static void set_discard_limits(struct pool *pool, struct queue_limits *limits) |
| { |
| /* |
| * FIXME: these limits may be incompatible with the pool's data device |
| */ |
| limits->max_discard_sectors = pool->sectors_per_block; |
| |
| /* |
| * This is just a hint, and not enforced. We have to cope with |
| * bios that cover a block partially. A discard that spans a block |
| * boundary is not sent to this target. |
| */ |
| limits->discard_granularity = pool->sectors_per_block << SECTOR_SHIFT; |
| limits->discard_zeroes_data = pool->pf.zero_new_blocks; |
| } |
| |
| static void pool_io_hints(struct dm_target *ti, struct queue_limits *limits) |
| { |
| struct pool_c *pt = ti->private; |
| struct pool *pool = pt->pool; |
| |
| blk_limits_io_min(limits, 0); |
| blk_limits_io_opt(limits, pool->sectors_per_block << SECTOR_SHIFT); |
| if (pool->pf.discard_enabled) |
| set_discard_limits(pool, limits); |
| } |
| |
| static struct target_type pool_target = { |
| .name = "thin-pool", |
| .features = DM_TARGET_SINGLETON | DM_TARGET_ALWAYS_WRITEABLE | |
| DM_TARGET_IMMUTABLE, |
| .version = {1, 2, 0}, |
| .module = THIS_MODULE, |
| .ctr = pool_ctr, |
| .dtr = pool_dtr, |
| .map = pool_map, |
| .postsuspend = pool_postsuspend, |
| .preresume = pool_preresume, |
| .resume = pool_resume, |
| .message = pool_message, |
| .status = pool_status, |
| .merge = pool_merge, |
| .iterate_devices = pool_iterate_devices, |
| .io_hints = pool_io_hints, |
| }; |
| |
| /*---------------------------------------------------------------- |
| * Thin target methods |
| *--------------------------------------------------------------*/ |
| static void thin_dtr(struct dm_target *ti) |
| { |
| struct thin_c *tc = ti->private; |
| |
| mutex_lock(&dm_thin_pool_table.mutex); |
| |
| __pool_dec(tc->pool); |
| dm_pool_close_thin_device(tc->td); |
| dm_put_device(ti, tc->pool_dev); |
| if (tc->origin_dev) |
| dm_put_device(ti, tc->origin_dev); |
| kfree(tc); |
| |
| mutex_unlock(&dm_thin_pool_table.mutex); |
| } |
| |
| /* |
| * Thin target parameters: |
| * |
| * <pool_dev> <dev_id> [origin_dev] |
| * |
| * pool_dev: the path to the pool (eg, /dev/mapper/my_pool) |
| * dev_id: the internal device identifier |
| * origin_dev: a device external to the pool that should act as the origin |
| * |
| * If the pool device has discards disabled, they get disabled for the thin |
| * device as well. |
| */ |
| static int thin_ctr(struct dm_target *ti, unsigned argc, char **argv) |
| { |
| int r; |
| struct thin_c *tc; |
| struct dm_dev *pool_dev, *origin_dev; |
| struct mapped_device *pool_md; |
| |
| mutex_lock(&dm_thin_pool_table.mutex); |
| |
| if (argc != 2 && argc != 3) { |
| ti->error = "Invalid argument count"; |
| r = -EINVAL; |
| goto out_unlock; |
| } |
| |
| tc = ti->private = kzalloc(sizeof(*tc), GFP_KERNEL); |
| if (!tc) { |
| ti->error = "Out of memory"; |
| r = -ENOMEM; |
| goto out_unlock; |
| } |
| |
| if (argc == 3) { |
| r = dm_get_device(ti, argv[2], FMODE_READ, &origin_dev); |
| if (r) { |
| ti->error = "Error opening origin device"; |
| goto bad_origin_dev; |
| } |
| tc->origin_dev = origin_dev; |
| } |
| |
| r = dm_get_device(ti, argv[0], dm_table_get_mode(ti->table), &pool_dev); |
| if (r) { |
| ti->error = "Error opening pool device"; |
| goto bad_pool_dev; |
| } |
| tc->pool_dev = pool_dev; |
| |
| if (read_dev_id(argv[1], (unsigned long long *)&tc->dev_id, 0)) { |
| ti->error = "Invalid device id"; |
| r = -EINVAL; |
| goto bad_common; |
| } |
| |
| pool_md = dm_get_md(tc->pool_dev->bdev->bd_dev); |
| if (!pool_md) { |
| ti->error = "Couldn't get pool mapped device"; |
| r = -EINVAL; |
| goto bad_common; |
| } |
| |
| tc->pool = __pool_table_lookup(pool_md); |
| if (!tc->pool) { |
| ti->error = "Couldn't find pool object"; |
| r = -EINVAL; |
| goto bad_pool_lookup; |
| } |
| __pool_inc(tc->pool); |
| |
| r = dm_pool_open_thin_device(tc->pool->pmd, tc->dev_id, &tc->td); |
| if (r) { |
| ti->error = "Couldn't open thin internal device"; |
| goto bad_thin_open; |
| } |
| |
| r = dm_set_target_max_io_len(ti, tc->pool->sectors_per_block); |
| if (r) |
| goto bad_thin_open; |
| |
| ti->num_flush_requests = 1; |
| ti->flush_supported = true; |
| |
| /* In case the pool supports discards, pass them on. */ |
| if (tc->pool->pf.discard_enabled) { |
| ti->discards_supported = true; |
| ti->num_discard_requests = 1; |
| ti->discard_zeroes_data_unsupported = true; |
| /* Discard requests must be split on a block boundary */ |
| ti->split_discard_requests = true; |
| } |
| |
| dm_put(pool_md); |
| |
| mutex_unlock(&dm_thin_pool_table.mutex); |
| |
| return 0; |
| |
| bad_thin_open: |
| __pool_dec(tc->pool); |
| bad_pool_lookup: |
| dm_put(pool_md); |
| bad_common: |
| dm_put_device(ti, tc->pool_dev); |
| bad_pool_dev: |
| if (tc->origin_dev) |
| dm_put_device(ti, tc->origin_dev); |
| bad_origin_dev: |
| kfree(tc); |
| out_unlock: |
| mutex_unlock(&dm_thin_pool_table.mutex); |
| |
| return r; |
| } |
| |
| static int thin_map(struct dm_target *ti, struct bio *bio, |
| union map_info *map_context) |
| { |
| bio->bi_sector = dm_target_offset(ti, bio->bi_sector); |
| |
| return thin_bio_map(ti, bio, map_context); |
| } |
| |
| static int thin_endio(struct dm_target *ti, |
| struct bio *bio, int err, |
| union map_info *map_context) |
| { |
| unsigned long flags; |
| struct dm_thin_endio_hook *h = map_context->ptr; |
| struct list_head work; |
| struct dm_thin_new_mapping *m, *tmp; |
| struct pool *pool = h->tc->pool; |
| |
| if (h->shared_read_entry) { |
| INIT_LIST_HEAD(&work); |
| ds_dec(h->shared_read_entry, &work); |
| |
| spin_lock_irqsave(&pool->lock, flags); |
| list_for_each_entry_safe(m, tmp, &work, list) { |
| list_del(&m->list); |
| m->quiesced = 1; |
| __maybe_add_mapping(m); |
| } |
| spin_unlock_irqrestore(&pool->lock, flags); |
| } |
| |
| if (h->all_io_entry) { |
| INIT_LIST_HEAD(&work); |
| ds_dec(h->all_io_entry, &work); |
| spin_lock_irqsave(&pool->lock, flags); |
| list_for_each_entry_safe(m, tmp, &work, list) |
| list_add(&m->list, &pool->prepared_discards); |
| spin_unlock_irqrestore(&pool->lock, flags); |
| } |
| |
| mempool_free(h, pool->endio_hook_pool); |
| |
| return 0; |
| } |
| |
| static void thin_postsuspend(struct dm_target *ti) |
| { |
| if (dm_noflush_suspending(ti)) |
| requeue_io((struct thin_c *)ti->private); |
| } |
| |
| /* |
| * <nr mapped sectors> <highest mapped sector> |
| */ |
| static int thin_status(struct dm_target *ti, status_type_t type, |
| char *result, unsigned maxlen) |
| { |
| int r; |
| ssize_t sz = 0; |
| dm_block_t mapped, highest; |
| char buf[BDEVNAME_SIZE]; |
| struct thin_c *tc = ti->private; |
| |
| if (!tc->td) |
| DMEMIT("-"); |
| else { |
| switch (type) { |
| case STATUSTYPE_INFO: |
| r = dm_thin_get_mapped_count(tc->td, &mapped); |
| if (r) |
| return r; |
| |
| r = dm_thin_get_highest_mapped_block(tc->td, &highest); |
| if (r < 0) |
| return r; |
| |
| DMEMIT("%llu ", mapped * tc->pool->sectors_per_block); |
| if (r) |
| DMEMIT("%llu", ((highest + 1) * |
| tc->pool->sectors_per_block) - 1); |
| else |
| DMEMIT("-"); |
| break; |
| |
| case STATUSTYPE_TABLE: |
| DMEMIT("%s %lu", |
| format_dev_t(buf, tc->pool_dev->bdev->bd_dev), |
| (unsigned long) tc->dev_id); |
| if (tc->origin_dev) |
| DMEMIT(" %s", format_dev_t(buf, tc->origin_dev->bdev->bd_dev)); |
| break; |
| } |
| } |
| |
| return 0; |
| } |
| |
| static int thin_iterate_devices(struct dm_target *ti, |
| iterate_devices_callout_fn fn, void *data) |
| { |
| sector_t blocks; |
| struct thin_c *tc = ti->private; |
| struct pool *pool = tc->pool; |
| |
| /* |
| * We can't call dm_pool_get_data_dev_size() since that blocks. So |
| * we follow a more convoluted path through to the pool's target. |
| */ |
| if (!pool->ti) |
| return 0; /* nothing is bound */ |
| |
| blocks = pool->ti->len; |
| (void) sector_div(blocks, pool->sectors_per_block); |
| if (blocks) |
| return fn(ti, tc->pool_dev, 0, pool->sectors_per_block * blocks, data); |
| |
| return 0; |
| } |
| |
| static void thin_io_hints(struct dm_target *ti, struct queue_limits *limits) |
| { |
| struct thin_c *tc = ti->private; |
| struct pool *pool = tc->pool; |
| |
| blk_limits_io_min(limits, 0); |
| blk_limits_io_opt(limits, pool->sectors_per_block << SECTOR_SHIFT); |
| set_discard_limits(pool, limits); |
| } |
| |
| static struct target_type thin_target = { |
| .name = "thin", |
| .version = {1, 2, 0}, |
| .module = THIS_MODULE, |
| .ctr = thin_ctr, |
| .dtr = thin_dtr, |
| .map = thin_map, |
| .end_io = thin_endio, |
| .postsuspend = thin_postsuspend, |
| .status = thin_status, |
| .iterate_devices = thin_iterate_devices, |
| .io_hints = thin_io_hints, |
| }; |
| |
| /*----------------------------------------------------------------*/ |
| |
| static int __init dm_thin_init(void) |
| { |
| int r; |
| |
| pool_table_init(); |
| |
| r = dm_register_target(&thin_target); |
| if (r) |
| return r; |
| |
| r = dm_register_target(&pool_target); |
| if (r) |
| goto bad_pool_target; |
| |
| r = -ENOMEM; |
| |
| _cell_cache = KMEM_CACHE(dm_bio_prison_cell, 0); |
| if (!_cell_cache) |
| goto bad_cell_cache; |
| |
| _new_mapping_cache = KMEM_CACHE(dm_thin_new_mapping, 0); |
| if (!_new_mapping_cache) |
| goto bad_new_mapping_cache; |
| |
| _endio_hook_cache = KMEM_CACHE(dm_thin_endio_hook, 0); |
| if (!_endio_hook_cache) |
| goto bad_endio_hook_cache; |
| |
| return 0; |
| |
| bad_endio_hook_cache: |
| kmem_cache_destroy(_new_mapping_cache); |
| bad_new_mapping_cache: |
| kmem_cache_destroy(_cell_cache); |
| bad_cell_cache: |
| dm_unregister_target(&pool_target); |
| bad_pool_target: |
| dm_unregister_target(&thin_target); |
| |
| return r; |
| } |
| |
| static void dm_thin_exit(void) |
| { |
| dm_unregister_target(&thin_target); |
| dm_unregister_target(&pool_target); |
| |
| kmem_cache_destroy(_cell_cache); |
| kmem_cache_destroy(_new_mapping_cache); |
| kmem_cache_destroy(_endio_hook_cache); |
| } |
| |
| module_init(dm_thin_init); |
| module_exit(dm_thin_exit); |
| |
| MODULE_DESCRIPTION(DM_NAME " thin provisioning target"); |
| MODULE_AUTHOR("Joe Thornber <dm-devel@redhat.com>"); |
| MODULE_LICENSE("GPL"); |