| /* |
| * Copyright (C) 2011-2012 Red Hat UK. |
| * |
| * This file is released under the GPL. |
| */ |
| |
| #include "dm-thin-metadata.h" |
| #include "dm-bio-prison.h" |
| #include "dm.h" |
| |
| #include <linux/device-mapper.h> |
| #include <linux/dm-io.h> |
| #include <linux/dm-kcopyd.h> |
| #include <linux/jiffies.h> |
| #include <linux/log2.h> |
| #include <linux/list.h> |
| #include <linux/rculist.h> |
| #include <linux/init.h> |
| #include <linux/module.h> |
| #include <linux/slab.h> |
| #include <linux/vmalloc.h> |
| #include <linux/sort.h> |
| #include <linux/rbtree.h> |
| |
| #define DM_MSG_PREFIX "thin" |
| |
| /* |
| * Tunable constants |
| */ |
| #define ENDIO_HOOK_POOL_SIZE 1024 |
| #define MAPPING_POOL_SIZE 1024 |
| #define COMMIT_PERIOD HZ |
| #define NO_SPACE_TIMEOUT_SECS 60 |
| |
| static unsigned no_space_timeout_secs = NO_SPACE_TIMEOUT_SECS; |
| |
| DECLARE_DM_KCOPYD_THROTTLE_WITH_MODULE_PARM(snapshot_copy_throttle, |
| "A percentage of time allocated for copy on write"); |
| |
| /* |
| * 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 dm_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. |
| */ |
| |
| /*----------------------------------------------------------------*/ |
| |
| /* |
| * Key building. |
| */ |
| enum lock_space { |
| VIRTUAL, |
| PHYSICAL |
| }; |
| |
| static void build_key(struct dm_thin_device *td, enum lock_space ls, |
| dm_block_t b, dm_block_t e, struct dm_cell_key *key) |
| { |
| key->virtual = (ls == VIRTUAL); |
| key->dev = dm_thin_dev_id(td); |
| key->block_begin = b; |
| key->block_end = e; |
| } |
| |
| static void build_data_key(struct dm_thin_device *td, dm_block_t b, |
| struct dm_cell_key *key) |
| { |
| build_key(td, PHYSICAL, b, b + 1llu, key); |
| } |
| |
| static void build_virtual_key(struct dm_thin_device *td, dm_block_t b, |
| struct dm_cell_key *key) |
| { |
| build_key(td, VIRTUAL, b, b + 1llu, key); |
| } |
| |
| /*----------------------------------------------------------------*/ |
| |
| #define THROTTLE_THRESHOLD (1 * HZ) |
| |
| struct throttle { |
| struct rw_semaphore lock; |
| unsigned long threshold; |
| bool throttle_applied; |
| }; |
| |
| static void throttle_init(struct throttle *t) |
| { |
| init_rwsem(&t->lock); |
| t->throttle_applied = false; |
| } |
| |
| static void throttle_work_start(struct throttle *t) |
| { |
| t->threshold = jiffies + THROTTLE_THRESHOLD; |
| } |
| |
| static void throttle_work_update(struct throttle *t) |
| { |
| if (!t->throttle_applied && jiffies > t->threshold) { |
| down_write(&t->lock); |
| t->throttle_applied = true; |
| } |
| } |
| |
| static void throttle_work_complete(struct throttle *t) |
| { |
| if (t->throttle_applied) { |
| t->throttle_applied = false; |
| up_write(&t->lock); |
| } |
| } |
| |
| static void throttle_lock(struct throttle *t) |
| { |
| down_read(&t->lock); |
| } |
| |
| static void throttle_unlock(struct throttle *t) |
| { |
| up_read(&t->lock); |
| } |
| |
| /*----------------------------------------------------------------*/ |
| |
| /* |
| * 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; |
| |
| /* |
| * The pool runs in 4 modes. Ordered in degraded order for comparisons. |
| */ |
| enum pool_mode { |
| PM_WRITE, /* metadata may be changed */ |
| PM_OUT_OF_DATA_SPACE, /* metadata may be changed, though data may not be allocated */ |
| PM_READ_ONLY, /* metadata may not be changed */ |
| PM_FAIL, /* all I/O fails */ |
| }; |
| |
| struct pool_features { |
| enum pool_mode mode; |
| |
| bool zero_new_blocks:1; |
| bool discard_enabled:1; |
| bool discard_passdown:1; |
| bool error_if_no_space:1; |
| }; |
| |
| struct thin_c; |
| typedef void (*process_bio_fn)(struct thin_c *tc, struct bio *bio); |
| typedef void (*process_cell_fn)(struct thin_c *tc, struct dm_bio_prison_cell *cell); |
| typedef void (*process_mapping_fn)(struct dm_thin_new_mapping *m); |
| |
| #define CELL_SORT_ARRAY_SIZE 8192 |
| |
| 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; |
| bool low_water_triggered:1; /* A dm event has been sent */ |
| bool suspended:1; |
| bool out_of_data_space:1; |
| |
| struct dm_bio_prison *prison; |
| struct dm_kcopyd_client *copier; |
| |
| struct workqueue_struct *wq; |
| struct throttle throttle; |
| struct work_struct worker; |
| struct delayed_work waker; |
| struct delayed_work no_space_timeout; |
| |
| unsigned long last_commit_jiffies; |
| unsigned ref_count; |
| |
| spinlock_t lock; |
| struct bio_list deferred_flush_bios; |
| struct list_head prepared_mappings; |
| struct list_head prepared_discards; |
| struct list_head prepared_discards_pt2; |
| struct list_head active_thins; |
| |
| struct dm_deferred_set *shared_read_ds; |
| struct dm_deferred_set *all_io_ds; |
| |
| struct dm_thin_new_mapping *next_mapping; |
| mempool_t *mapping_pool; |
| |
| process_bio_fn process_bio; |
| process_bio_fn process_discard; |
| |
| process_cell_fn process_cell; |
| process_cell_fn process_discard_cell; |
| |
| process_mapping_fn process_prepared_mapping; |
| process_mapping_fn process_prepared_discard; |
| process_mapping_fn process_prepared_discard_pt2; |
| |
| struct dm_bio_prison_cell **cell_sort_array; |
| }; |
| |
| static enum pool_mode get_pool_mode(struct pool *pool); |
| static void metadata_operation_failed(struct pool *pool, const char *op, int r); |
| |
| /* |
| * 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 requested_pf; /* Features requested during table load */ |
| struct pool_features adjusted_pf; /* Features used after adjusting for constituent devices */ |
| }; |
| |
| /* |
| * Target context for a thin. |
| */ |
| struct thin_c { |
| struct list_head list; |
| struct dm_dev *pool_dev; |
| struct dm_dev *origin_dev; |
| sector_t origin_size; |
| dm_thin_id dev_id; |
| |
| struct pool *pool; |
| struct dm_thin_device *td; |
| struct mapped_device *thin_md; |
| |
| bool requeue_mode:1; |
| spinlock_t lock; |
| struct list_head deferred_cells; |
| struct bio_list deferred_bio_list; |
| struct bio_list retry_on_resume_list; |
| struct rb_root sort_bio_list; /* sorted list of deferred bios */ |
| |
| /* |
| * Ensures the thin is not destroyed until the worker has finished |
| * iterating the active_thins list. |
| */ |
| atomic_t refcount; |
| struct completion can_destroy; |
| }; |
| |
| /*----------------------------------------------------------------*/ |
| |
| static bool block_size_is_power_of_two(struct pool *pool) |
| { |
| return pool->sectors_per_block_shift >= 0; |
| } |
| |
| static sector_t block_to_sectors(struct pool *pool, dm_block_t b) |
| { |
| return block_size_is_power_of_two(pool) ? |
| (b << pool->sectors_per_block_shift) : |
| (b * pool->sectors_per_block); |
| } |
| |
| /*----------------------------------------------------------------*/ |
| |
| struct discard_op { |
| struct thin_c *tc; |
| struct blk_plug plug; |
| struct bio *parent_bio; |
| struct bio *bio; |
| }; |
| |
| static void begin_discard(struct discard_op *op, struct thin_c *tc, struct bio *parent) |
| { |
| BUG_ON(!parent); |
| |
| op->tc = tc; |
| blk_start_plug(&op->plug); |
| op->parent_bio = parent; |
| op->bio = NULL; |
| } |
| |
| static int issue_discard(struct discard_op *op, dm_block_t data_b, dm_block_t data_e) |
| { |
| struct thin_c *tc = op->tc; |
| sector_t s = block_to_sectors(tc->pool, data_b); |
| sector_t len = block_to_sectors(tc->pool, data_e - data_b); |
| |
| return __blkdev_issue_discard(tc->pool_dev->bdev, s, len, |
| GFP_NOWAIT, 0, &op->bio); |
| } |
| |
| static void end_discard(struct discard_op *op, int r) |
| { |
| if (op->bio) { |
| /* |
| * Even if one of the calls to issue_discard failed, we |
| * need to wait for the chain to complete. |
| */ |
| bio_chain(op->bio, op->parent_bio); |
| bio_set_op_attrs(op->bio, REQ_OP_DISCARD, 0); |
| submit_bio(op->bio); |
| } |
| |
| blk_finish_plug(&op->plug); |
| |
| /* |
| * Even if r is set, there could be sub discards in flight that we |
| * need to wait for. |
| */ |
| if (r && !op->parent_bio->bi_error) |
| op->parent_bio->bi_error = r; |
| bio_endio(op->parent_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); |
| } |
| |
| /*----------------------------------------------------------------*/ |
| |
| static int bio_detain(struct pool *pool, struct dm_cell_key *key, struct bio *bio, |
| struct dm_bio_prison_cell **cell_result) |
| { |
| int r; |
| struct dm_bio_prison_cell *cell_prealloc; |
| |
| /* |
| * Allocate a cell from the prison's mempool. |
| * This might block but it can't fail. |
| */ |
| cell_prealloc = dm_bio_prison_alloc_cell(pool->prison, GFP_NOIO); |
| |
| r = dm_bio_detain(pool->prison, key, bio, cell_prealloc, cell_result); |
| if (r) |
| /* |
| * We reused an old cell; we can get rid of |
| * the new one. |
| */ |
| dm_bio_prison_free_cell(pool->prison, cell_prealloc); |
| |
| return r; |
| } |
| |
| static void cell_release(struct pool *pool, |
| struct dm_bio_prison_cell *cell, |
| struct bio_list *bios) |
| { |
| dm_cell_release(pool->prison, cell, bios); |
| dm_bio_prison_free_cell(pool->prison, cell); |
| } |
| |
| static void cell_visit_release(struct pool *pool, |
| void (*fn)(void *, struct dm_bio_prison_cell *), |
| void *context, |
| struct dm_bio_prison_cell *cell) |
| { |
| dm_cell_visit_release(pool->prison, fn, context, cell); |
| dm_bio_prison_free_cell(pool->prison, cell); |
| } |
| |
| static void cell_release_no_holder(struct pool *pool, |
| struct dm_bio_prison_cell *cell, |
| struct bio_list *bios) |
| { |
| dm_cell_release_no_holder(pool->prison, cell, bios); |
| dm_bio_prison_free_cell(pool->prison, cell); |
| } |
| |
| static void cell_error_with_code(struct pool *pool, |
| struct dm_bio_prison_cell *cell, int error_code) |
| { |
| dm_cell_error(pool->prison, cell, error_code); |
| dm_bio_prison_free_cell(pool->prison, cell); |
| } |
| |
| static int get_pool_io_error_code(struct pool *pool) |
| { |
| return pool->out_of_data_space ? -ENOSPC : -EIO; |
| } |
| |
| static void cell_error(struct pool *pool, struct dm_bio_prison_cell *cell) |
| { |
| int error = get_pool_io_error_code(pool); |
| |
| cell_error_with_code(pool, cell, error); |
| } |
| |
| static void cell_success(struct pool *pool, struct dm_bio_prison_cell *cell) |
| { |
| cell_error_with_code(pool, cell, 0); |
| } |
| |
| static void cell_requeue(struct pool *pool, struct dm_bio_prison_cell *cell) |
| { |
| cell_error_with_code(pool, cell, DM_ENDIO_REQUEUE); |
| } |
| |
| /*----------------------------------------------------------------*/ |
| |
| /* |
| * 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 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; |
| struct dm_bio_prison_cell *cell; |
| }; |
| |
| static void __merge_bio_list(struct bio_list *bios, struct bio_list *master) |
| { |
| bio_list_merge(bios, master); |
| bio_list_init(master); |
| } |
| |
| static void error_bio_list(struct bio_list *bios, int error) |
| { |
| struct bio *bio; |
| |
| while ((bio = bio_list_pop(bios))) { |
| bio->bi_error = error; |
| bio_endio(bio); |
| } |
| } |
| |
| static void error_thin_bio_list(struct thin_c *tc, struct bio_list *master, int error) |
| { |
| struct bio_list bios; |
| unsigned long flags; |
| |
| bio_list_init(&bios); |
| |
| spin_lock_irqsave(&tc->lock, flags); |
| __merge_bio_list(&bios, master); |
| spin_unlock_irqrestore(&tc->lock, flags); |
| |
| error_bio_list(&bios, error); |
| } |
| |
| static void requeue_deferred_cells(struct thin_c *tc) |
| { |
| struct pool *pool = tc->pool; |
| unsigned long flags; |
| struct list_head cells; |
| struct dm_bio_prison_cell *cell, *tmp; |
| |
| INIT_LIST_HEAD(&cells); |
| |
| spin_lock_irqsave(&tc->lock, flags); |
| list_splice_init(&tc->deferred_cells, &cells); |
| spin_unlock_irqrestore(&tc->lock, flags); |
| |
| list_for_each_entry_safe(cell, tmp, &cells, user_list) |
| cell_requeue(pool, cell); |
| } |
| |
| static void requeue_io(struct thin_c *tc) |
| { |
| struct bio_list bios; |
| unsigned long flags; |
| |
| bio_list_init(&bios); |
| |
| spin_lock_irqsave(&tc->lock, flags); |
| __merge_bio_list(&bios, &tc->deferred_bio_list); |
| __merge_bio_list(&bios, &tc->retry_on_resume_list); |
| spin_unlock_irqrestore(&tc->lock, flags); |
| |
| error_bio_list(&bios, DM_ENDIO_REQUEUE); |
| requeue_deferred_cells(tc); |
| } |
| |
| static void error_retry_list_with_code(struct pool *pool, int error) |
| { |
| struct thin_c *tc; |
| |
| rcu_read_lock(); |
| list_for_each_entry_rcu(tc, &pool->active_thins, list) |
| error_thin_bio_list(tc, &tc->retry_on_resume_list, error); |
| rcu_read_unlock(); |
| } |
| |
| static void error_retry_list(struct pool *pool) |
| { |
| int error = get_pool_io_error_code(pool); |
| |
| error_retry_list_with_code(pool, error); |
| } |
| |
| /* |
| * 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) |
| { |
| struct pool *pool = tc->pool; |
| sector_t block_nr = bio->bi_iter.bi_sector; |
| |
| if (block_size_is_power_of_two(pool)) |
| block_nr >>= pool->sectors_per_block_shift; |
| else |
| (void) sector_div(block_nr, pool->sectors_per_block); |
| |
| return block_nr; |
| } |
| |
| /* |
| * Returns the _complete_ blocks that this bio covers. |
| */ |
| static void get_bio_block_range(struct thin_c *tc, struct bio *bio, |
| dm_block_t *begin, dm_block_t *end) |
| { |
| struct pool *pool = tc->pool; |
| sector_t b = bio->bi_iter.bi_sector; |
| sector_t e = b + (bio->bi_iter.bi_size >> SECTOR_SHIFT); |
| |
| b += pool->sectors_per_block - 1ull; /* so we round up */ |
| |
| if (block_size_is_power_of_two(pool)) { |
| b >>= pool->sectors_per_block_shift; |
| e >>= pool->sectors_per_block_shift; |
| } else { |
| (void) sector_div(b, pool->sectors_per_block); |
| (void) sector_div(e, pool->sectors_per_block); |
| } |
| |
| if (e < b) |
| /* Can happen if the bio is within a single block. */ |
| e = b; |
| |
| *begin = b; |
| *end = e; |
| } |
| |
| 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_iter.bi_sector; |
| |
| bio->bi_bdev = tc->pool_dev->bdev; |
| if (block_size_is_power_of_two(pool)) |
| bio->bi_iter.bi_sector = |
| (block << pool->sectors_per_block_shift) | |
| (bi_sector & (pool->sectors_per_block - 1)); |
| else |
| bio->bi_iter.bi_sector = (block * pool->sectors_per_block) + |
| sector_div(bi_sector, pool->sectors_per_block); |
| } |
| |
| static void remap_to_origin(struct thin_c *tc, struct bio *bio) |
| { |
| bio->bi_bdev = tc->origin_dev->bdev; |
| } |
| |
| static int bio_triggers_commit(struct thin_c *tc, struct bio *bio) |
| { |
| return op_is_flush(bio->bi_opf) && |
| dm_thin_changed_this_transaction(tc->td); |
| } |
| |
| static void inc_all_io_entry(struct pool *pool, struct bio *bio) |
| { |
| struct dm_thin_endio_hook *h; |
| |
| if (bio_op(bio) == REQ_OP_DISCARD) |
| return; |
| |
| h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook)); |
| h->all_io_entry = dm_deferred_entry_inc(pool->all_io_ds); |
| } |
| |
| static void issue(struct thin_c *tc, struct bio *bio) |
| { |
| struct pool *pool = tc->pool; |
| unsigned long flags; |
| |
| if (!bio_triggers_commit(tc, bio)) { |
| generic_make_request(bio); |
| return; |
| } |
| |
| /* |
| * Complete bio with an error if earlier I/O caused changes to |
| * the metadata that can't be committed e.g, due to I/O errors |
| * on the metadata device. |
| */ |
| if (dm_thin_aborted_changes(tc->td)) { |
| bio_io_error(bio); |
| return; |
| } |
| |
| /* |
| * Batch together any bios that trigger commits and then issue a |
| * single commit for them in process_deferred_bios(). |
| */ |
| spin_lock_irqsave(&pool->lock, flags); |
| bio_list_add(&pool->deferred_flush_bios, bio); |
| spin_unlock_irqrestore(&pool->lock, flags); |
| } |
| |
| 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); |
| } |
| |
| /*----------------------------------------------------------------*/ |
| |
| /* |
| * Bio endio functions. |
| */ |
| struct dm_thin_new_mapping { |
| struct list_head list; |
| |
| bool pass_discard:1; |
| bool maybe_shared:1; |
| |
| /* |
| * Track quiescing, copying and zeroing preparation actions. When this |
| * counter hits zero the block is prepared and can be inserted into the |
| * btree. |
| */ |
| atomic_t prepare_actions; |
| |
| int err; |
| struct thin_c *tc; |
| dm_block_t virt_begin, virt_end; |
| dm_block_t data_block; |
| struct dm_bio_prison_cell *cell; |
| |
| /* |
| * 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 __complete_mapping_preparation(struct dm_thin_new_mapping *m) |
| { |
| struct pool *pool = m->tc->pool; |
| |
| if (atomic_dec_and_test(&m->prepare_actions)) { |
| list_add_tail(&m->list, &pool->prepared_mappings); |
| wake_worker(pool); |
| } |
| } |
| |
| static void complete_mapping_preparation(struct dm_thin_new_mapping *m) |
| { |
| unsigned long flags; |
| struct pool *pool = m->tc->pool; |
| |
| spin_lock_irqsave(&pool->lock, flags); |
| __complete_mapping_preparation(m); |
| spin_unlock_irqrestore(&pool->lock, flags); |
| } |
| |
| static void copy_complete(int read_err, unsigned long write_err, void *context) |
| { |
| struct dm_thin_new_mapping *m = context; |
| |
| m->err = read_err || write_err ? -EIO : 0; |
| complete_mapping_preparation(m); |
| } |
| |
| static void overwrite_endio(struct bio *bio) |
| { |
| struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook)); |
| struct dm_thin_new_mapping *m = h->overwrite_mapping; |
| |
| bio->bi_end_io = m->saved_bi_end_io; |
| |
| m->err = bio->bi_error; |
| complete_mapping_preparation(m); |
| } |
| |
| /*----------------------------------------------------------------*/ |
| |
| /* |
| * Workqueue. |
| */ |
| |
| /* |
| * Prepared mapping jobs. |
| */ |
| |
| /* |
| * This sends the bios in the cell, except the original holder, back |
| * to the deferred_bios list. |
| */ |
| static void cell_defer_no_holder(struct thin_c *tc, struct dm_bio_prison_cell *cell) |
| { |
| struct pool *pool = tc->pool; |
| unsigned long 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); |
| } |
| |
| static void thin_defer_bio(struct thin_c *tc, struct bio *bio); |
| |
| struct remap_info { |
| struct thin_c *tc; |
| struct bio_list defer_bios; |
| struct bio_list issue_bios; |
| }; |
| |
| static void __inc_remap_and_issue_cell(void *context, |
| struct dm_bio_prison_cell *cell) |
| { |
| struct remap_info *info = context; |
| struct bio *bio; |
| |
| while ((bio = bio_list_pop(&cell->bios))) { |
| if (op_is_flush(bio->bi_opf) || bio_op(bio) == REQ_OP_DISCARD) |
| bio_list_add(&info->defer_bios, bio); |
| else { |
| inc_all_io_entry(info->tc->pool, bio); |
| |
| /* |
| * We can't issue the bios with the bio prison lock |
| * held, so we add them to a list to issue on |
| * return from this function. |
| */ |
| bio_list_add(&info->issue_bios, bio); |
| } |
| } |
| } |
| |
| static void inc_remap_and_issue_cell(struct thin_c *tc, |
| struct dm_bio_prison_cell *cell, |
| dm_block_t block) |
| { |
| struct bio *bio; |
| struct remap_info info; |
| |
| info.tc = tc; |
| bio_list_init(&info.defer_bios); |
| bio_list_init(&info.issue_bios); |
| |
| /* |
| * We have to be careful to inc any bios we're about to issue |
| * before the cell is released, and avoid a race with new bios |
| * being added to the cell. |
| */ |
| cell_visit_release(tc->pool, __inc_remap_and_issue_cell, |
| &info, cell); |
| |
| while ((bio = bio_list_pop(&info.defer_bios))) |
| thin_defer_bio(tc, bio); |
| |
| while ((bio = bio_list_pop(&info.issue_bios))) |
| remap_and_issue(info.tc, bio, block); |
| } |
| |
| static void process_prepared_mapping_fail(struct dm_thin_new_mapping *m) |
| { |
| cell_error(m->tc->pool, m->cell); |
| list_del(&m->list); |
| mempool_free(m, m->tc->pool->mapping_pool); |
| } |
| |
| static void process_prepared_mapping(struct dm_thin_new_mapping *m) |
| { |
| struct thin_c *tc = m->tc; |
| struct pool *pool = tc->pool; |
| struct bio *bio = m->bio; |
| int r; |
| |
| if (m->err) { |
| cell_error(pool, 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_begin, m->data_block); |
| if (r) { |
| metadata_operation_failed(pool, "dm_thin_insert_block", r); |
| cell_error(pool, 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) { |
| inc_remap_and_issue_cell(tc, m->cell, m->data_block); |
| bio_endio(bio); |
| } else { |
| inc_all_io_entry(tc->pool, m->cell->holder); |
| remap_and_issue(tc, m->cell->holder, m->data_block); |
| inc_remap_and_issue_cell(tc, m->cell, m->data_block); |
| } |
| |
| out: |
| list_del(&m->list); |
| mempool_free(m, pool->mapping_pool); |
| } |
| |
| /*----------------------------------------------------------------*/ |
| |
| static void free_discard_mapping(struct dm_thin_new_mapping *m) |
| { |
| struct thin_c *tc = m->tc; |
| if (m->cell) |
| cell_defer_no_holder(tc, m->cell); |
| mempool_free(m, tc->pool->mapping_pool); |
| } |
| |
| static void process_prepared_discard_fail(struct dm_thin_new_mapping *m) |
| { |
| bio_io_error(m->bio); |
| free_discard_mapping(m); |
| } |
| |
| static void process_prepared_discard_success(struct dm_thin_new_mapping *m) |
| { |
| bio_endio(m->bio); |
| free_discard_mapping(m); |
| } |
| |
| static void process_prepared_discard_no_passdown(struct dm_thin_new_mapping *m) |
| { |
| int r; |
| struct thin_c *tc = m->tc; |
| |
| r = dm_thin_remove_range(tc->td, m->cell->key.block_begin, m->cell->key.block_end); |
| if (r) { |
| metadata_operation_failed(tc->pool, "dm_thin_remove_range", r); |
| bio_io_error(m->bio); |
| } else |
| bio_endio(m->bio); |
| |
| cell_defer_no_holder(tc, m->cell); |
| mempool_free(m, tc->pool->mapping_pool); |
| } |
| |
| /*----------------------------------------------------------------*/ |
| |
| static void passdown_double_checking_shared_status(struct dm_thin_new_mapping *m, |
| struct bio *discard_parent) |
| { |
| /* |
| * We've already unmapped this range of blocks, but before we |
| * passdown we have to check that these blocks are now unused. |
| */ |
| int r = 0; |
| bool used = true; |
| struct thin_c *tc = m->tc; |
| struct pool *pool = tc->pool; |
| dm_block_t b = m->data_block, e, end = m->data_block + m->virt_end - m->virt_begin; |
| struct discard_op op; |
| |
| begin_discard(&op, tc, discard_parent); |
| while (b != end) { |
| /* find start of unmapped run */ |
| for (; b < end; b++) { |
| r = dm_pool_block_is_used(pool->pmd, b, &used); |
| if (r) |
| goto out; |
| |
| if (!used) |
| break; |
| } |
| |
| if (b == end) |
| break; |
| |
| /* find end of run */ |
| for (e = b + 1; e != end; e++) { |
| r = dm_pool_block_is_used(pool->pmd, e, &used); |
| if (r) |
| goto out; |
| |
| if (used) |
| break; |
| } |
| |
| r = issue_discard(&op, b, e); |
| if (r) |
| goto out; |
| |
| b = e; |
| } |
| out: |
| end_discard(&op, r); |
| } |
| |
| static void queue_passdown_pt2(struct dm_thin_new_mapping *m) |
| { |
| unsigned long flags; |
| struct pool *pool = m->tc->pool; |
| |
| spin_lock_irqsave(&pool->lock, flags); |
| list_add_tail(&m->list, &pool->prepared_discards_pt2); |
| spin_unlock_irqrestore(&pool->lock, flags); |
| wake_worker(pool); |
| } |
| |
| static void passdown_endio(struct bio *bio) |
| { |
| /* |
| * It doesn't matter if the passdown discard failed, we still want |
| * to unmap (we ignore err). |
| */ |
| queue_passdown_pt2(bio->bi_private); |
| } |
| |
| static void process_prepared_discard_passdown_pt1(struct dm_thin_new_mapping *m) |
| { |
| int r; |
| struct thin_c *tc = m->tc; |
| struct pool *pool = tc->pool; |
| struct bio *discard_parent; |
| dm_block_t data_end = m->data_block + (m->virt_end - m->virt_begin); |
| |
| /* |
| * Only this thread allocates blocks, so we can be sure that the |
| * newly unmapped blocks will not be allocated before the end of |
| * the function. |
| */ |
| r = dm_thin_remove_range(tc->td, m->virt_begin, m->virt_end); |
| if (r) { |
| metadata_operation_failed(pool, "dm_thin_remove_range", r); |
| bio_io_error(m->bio); |
| cell_defer_no_holder(tc, m->cell); |
| mempool_free(m, pool->mapping_pool); |
| return; |
| } |
| |
| discard_parent = bio_alloc(GFP_NOIO, 1); |
| if (!discard_parent) { |
| DMWARN("%s: unable to allocate top level discard bio for passdown. Skipping passdown.", |
| dm_device_name(tc->pool->pool_md)); |
| queue_passdown_pt2(m); |
| |
| } else { |
| discard_parent->bi_end_io = passdown_endio; |
| discard_parent->bi_private = m; |
| |
| if (m->maybe_shared) |
| passdown_double_checking_shared_status(m, discard_parent); |
| else { |
| struct discard_op op; |
| |
| begin_discard(&op, tc, discard_parent); |
| r = issue_discard(&op, m->data_block, data_end); |
| end_discard(&op, r); |
| } |
| } |
| |
| /* |
| * Increment the unmapped blocks. This prevents a race between the |
| * passdown io and reallocation of freed blocks. |
| */ |
| r = dm_pool_inc_data_range(pool->pmd, m->data_block, data_end); |
| if (r) { |
| metadata_operation_failed(pool, "dm_pool_inc_data_range", r); |
| bio_io_error(m->bio); |
| cell_defer_no_holder(tc, m->cell); |
| mempool_free(m, pool->mapping_pool); |
| return; |
| } |
| } |
| |
| static void process_prepared_discard_passdown_pt2(struct dm_thin_new_mapping *m) |
| { |
| int r; |
| struct thin_c *tc = m->tc; |
| struct pool *pool = tc->pool; |
| |
| /* |
| * The passdown has completed, so now we can decrement all those |
| * unmapped blocks. |
| */ |
| r = dm_pool_dec_data_range(pool->pmd, m->data_block, |
| m->data_block + (m->virt_end - m->virt_begin)); |
| if (r) { |
| metadata_operation_failed(pool, "dm_pool_dec_data_range", r); |
| bio_io_error(m->bio); |
| } else |
| bio_endio(m->bio); |
| |
| cell_defer_no_holder(tc, m->cell); |
| mempool_free(m, pool->mapping_pool); |
| } |
| |
| static void process_prepared(struct pool *pool, struct list_head *head, |
| process_mapping_fn *fn) |
| { |
| 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_iter.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 *m = pool->next_mapping; |
| |
| BUG_ON(!pool->next_mapping); |
| |
| memset(m, 0, sizeof(struct dm_thin_new_mapping)); |
| INIT_LIST_HEAD(&m->list); |
| m->bio = NULL; |
| |
| pool->next_mapping = NULL; |
| |
| return m; |
| } |
| |
| static void ll_zero(struct thin_c *tc, struct dm_thin_new_mapping *m, |
| sector_t begin, sector_t end) |
| { |
| int r; |
| struct dm_io_region to; |
| |
| to.bdev = tc->pool_dev->bdev; |
| to.sector = begin; |
| to.count = end - begin; |
| |
| r = dm_kcopyd_zero(tc->pool->copier, 1, &to, 0, copy_complete, m); |
| if (r < 0) { |
| DMERR_LIMIT("dm_kcopyd_zero() failed"); |
| copy_complete(1, 1, m); |
| } |
| } |
| |
| static void remap_and_issue_overwrite(struct thin_c *tc, struct bio *bio, |
| dm_block_t data_begin, |
| struct dm_thin_new_mapping *m) |
| { |
| struct pool *pool = tc->pool; |
| struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook)); |
| |
| h->overwrite_mapping = m; |
| m->bio = bio; |
| save_and_set_endio(bio, &m->saved_bi_end_io, overwrite_endio); |
| inc_all_io_entry(pool, bio); |
| remap_and_issue(tc, bio, data_begin); |
| } |
| |
| /* |
| * A partial copy also needs to zero the uncopied region. |
| */ |
| 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, |
| sector_t len) |
| { |
| int r; |
| struct pool *pool = tc->pool; |
| struct dm_thin_new_mapping *m = get_next_mapping(pool); |
| |
| m->tc = tc; |
| m->virt_begin = virt_block; |
| m->virt_end = virt_block + 1u; |
| m->data_block = data_dest; |
| m->cell = cell; |
| |
| /* |
| * quiesce action + copy action + an extra reference held for the |
| * duration of this function (we may need to inc later for a |
| * partial zero). |
| */ |
| atomic_set(&m->prepare_actions, 3); |
| |
| if (!dm_deferred_set_add_work(pool->shared_read_ds, &m->list)) |
| complete_mapping_preparation(m); /* already quiesced */ |
| |
| /* |
| * 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)) |
| remap_and_issue_overwrite(tc, bio, data_dest, m); |
| else { |
| struct dm_io_region from, to; |
| |
| from.bdev = origin->bdev; |
| from.sector = data_origin * pool->sectors_per_block; |
| from.count = len; |
| |
| to.bdev = tc->pool_dev->bdev; |
| to.sector = data_dest * pool->sectors_per_block; |
| to.count = len; |
| |
| r = dm_kcopyd_copy(pool->copier, &from, 1, &to, |
| 0, copy_complete, m); |
| if (r < 0) { |
| DMERR_LIMIT("dm_kcopyd_copy() failed"); |
| copy_complete(1, 1, m); |
| |
| /* |
| * We allow the zero to be issued, to simplify the |
| * error path. Otherwise we'd need to start |
| * worrying about decrementing the prepare_actions |
| * counter. |
| */ |
| } |
| |
| /* |
| * Do we need to zero a tail region? |
| */ |
| if (len < pool->sectors_per_block && pool->pf.zero_new_blocks) { |
| atomic_inc(&m->prepare_actions); |
| ll_zero(tc, m, |
| data_dest * pool->sectors_per_block + len, |
| (data_dest + 1) * pool->sectors_per_block); |
| } |
| } |
| |
| complete_mapping_preparation(m); /* drop our ref */ |
| } |
| |
| 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, |
| tc->pool->sectors_per_block); |
| } |
| |
| 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); |
| |
| atomic_set(&m->prepare_actions, 1); /* no need to quiesce */ |
| m->tc = tc; |
| m->virt_begin = virt_block; |
| m->virt_end = virt_block + 1u; |
| m->data_block = data_block; |
| m->cell = cell; |
| |
| /* |
| * 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) { |
| if (io_overwrites_block(pool, bio)) |
| remap_and_issue_overwrite(tc, bio, data_block, m); |
| else |
| ll_zero(tc, m, data_block * pool->sectors_per_block, |
| (data_block + 1) * pool->sectors_per_block); |
| } else |
| process_prepared_mapping(m); |
| } |
| |
| 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) |
| { |
| struct pool *pool = tc->pool; |
| sector_t virt_block_begin = virt_block * pool->sectors_per_block; |
| sector_t virt_block_end = (virt_block + 1) * pool->sectors_per_block; |
| |
| if (virt_block_end <= tc->origin_size) |
| schedule_copy(tc, virt_block, tc->origin_dev, |
| virt_block, data_dest, cell, bio, |
| pool->sectors_per_block); |
| |
| else if (virt_block_begin < tc->origin_size) |
| schedule_copy(tc, virt_block, tc->origin_dev, |
| virt_block, data_dest, cell, bio, |
| tc->origin_size - virt_block_begin); |
| |
| else |
| schedule_zero(tc, virt_block, data_dest, cell, bio); |
| } |
| |
| static void set_pool_mode(struct pool *pool, enum pool_mode new_mode); |
| |
| static void check_for_space(struct pool *pool) |
| { |
| int r; |
| dm_block_t nr_free; |
| |
| if (get_pool_mode(pool) != PM_OUT_OF_DATA_SPACE) |
| return; |
| |
| r = dm_pool_get_free_block_count(pool->pmd, &nr_free); |
| if (r) |
| return; |
| |
| if (nr_free) |
| set_pool_mode(pool, PM_WRITE); |
| } |
| |
| /* |
| * A non-zero return indicates read_only or fail_io mode. |
| * Many callers don't care about the return value. |
| */ |
| static int commit(struct pool *pool) |
| { |
| int r; |
| |
| if (get_pool_mode(pool) >= PM_READ_ONLY) |
| return -EINVAL; |
| |
| r = dm_pool_commit_metadata(pool->pmd); |
| if (r) |
| metadata_operation_failed(pool, "dm_pool_commit_metadata", r); |
| else |
| check_for_space(pool); |
| |
| return r; |
| } |
| |
| static void check_low_water_mark(struct pool *pool, dm_block_t free_blocks) |
| { |
| unsigned long flags; |
| |
| if (free_blocks <= pool->low_water_blocks && !pool->low_water_triggered) { |
| DMWARN("%s: reached low water mark for data device: sending event.", |
| dm_device_name(pool->pool_md)); |
| spin_lock_irqsave(&pool->lock, flags); |
| pool->low_water_triggered = true; |
| spin_unlock_irqrestore(&pool->lock, flags); |
| dm_table_event(pool->ti->table); |
| } |
| } |
| |
| static int alloc_data_block(struct thin_c *tc, dm_block_t *result) |
| { |
| int r; |
| dm_block_t free_blocks; |
| struct pool *pool = tc->pool; |
| |
| if (WARN_ON(get_pool_mode(pool) != PM_WRITE)) |
| return -EINVAL; |
| |
| r = dm_pool_get_free_block_count(pool->pmd, &free_blocks); |
| if (r) { |
| metadata_operation_failed(pool, "dm_pool_get_free_block_count", r); |
| return r; |
| } |
| |
| check_low_water_mark(pool, free_blocks); |
| |
| if (!free_blocks) { |
| /* |
| * Try to commit to see if that will free up some |
| * more space. |
| */ |
| r = commit(pool); |
| if (r) |
| return r; |
| |
| r = dm_pool_get_free_block_count(pool->pmd, &free_blocks); |
| if (r) { |
| metadata_operation_failed(pool, "dm_pool_get_free_block_count", r); |
| return r; |
| } |
| |
| if (!free_blocks) { |
| set_pool_mode(pool, PM_OUT_OF_DATA_SPACE); |
| return -ENOSPC; |
| } |
| } |
| |
| r = dm_pool_alloc_data_block(pool->pmd, result); |
| if (r) { |
| metadata_operation_failed(pool, "dm_pool_alloc_data_block", 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_per_bio_data(bio, sizeof(struct dm_thin_endio_hook)); |
| struct thin_c *tc = h->tc; |
| unsigned long flags; |
| |
| spin_lock_irqsave(&tc->lock, flags); |
| bio_list_add(&tc->retry_on_resume_list, bio); |
| spin_unlock_irqrestore(&tc->lock, flags); |
| } |
| |
| static int should_error_unserviceable_bio(struct pool *pool) |
| { |
| enum pool_mode m = get_pool_mode(pool); |
| |
| switch (m) { |
| case PM_WRITE: |
| /* Shouldn't get here */ |
| DMERR_LIMIT("bio unserviceable, yet pool is in PM_WRITE mode"); |
| return -EIO; |
| |
| case PM_OUT_OF_DATA_SPACE: |
| return pool->pf.error_if_no_space ? -ENOSPC : 0; |
| |
| case PM_READ_ONLY: |
| case PM_FAIL: |
| return -EIO; |
| default: |
| /* Shouldn't get here */ |
| DMERR_LIMIT("bio unserviceable, yet pool has an unknown mode"); |
| return -EIO; |
| } |
| } |
| |
| static void handle_unserviceable_bio(struct pool *pool, struct bio *bio) |
| { |
| int error = should_error_unserviceable_bio(pool); |
| |
| if (error) { |
| bio->bi_error = error; |
| bio_endio(bio); |
| } else |
| retry_on_resume(bio); |
| } |
| |
| static void retry_bios_on_resume(struct pool *pool, struct dm_bio_prison_cell *cell) |
| { |
| struct bio *bio; |
| struct bio_list bios; |
| int error; |
| |
| error = should_error_unserviceable_bio(pool); |
| if (error) { |
| cell_error_with_code(pool, cell, error); |
| return; |
| } |
| |
| bio_list_init(&bios); |
| cell_release(pool, cell, &bios); |
| |
| while ((bio = bio_list_pop(&bios))) |
| retry_on_resume(bio); |
| } |
| |
| static void process_discard_cell_no_passdown(struct thin_c *tc, |
| struct dm_bio_prison_cell *virt_cell) |
| { |
| struct pool *pool = tc->pool; |
| struct dm_thin_new_mapping *m = get_next_mapping(pool); |
| |
| /* |
| * We don't need to lock the data blocks, since there's no |
| * passdown. We only lock data blocks for allocation and breaking sharing. |
| */ |
| m->tc = tc; |
| m->virt_begin = virt_cell->key.block_begin; |
| m->virt_end = virt_cell->key.block_end; |
| m->cell = virt_cell; |
| m->bio = virt_cell->holder; |
| |
| if (!dm_deferred_set_add_work(pool->all_io_ds, &m->list)) |
| pool->process_prepared_discard(m); |
| } |
| |
| static void break_up_discard_bio(struct thin_c *tc, dm_block_t begin, dm_block_t end, |
| struct bio *bio) |
| { |
| struct pool *pool = tc->pool; |
| |
| int r; |
| bool maybe_shared; |
| struct dm_cell_key data_key; |
| struct dm_bio_prison_cell *data_cell; |
| struct dm_thin_new_mapping *m; |
| dm_block_t virt_begin, virt_end, data_begin; |
| |
| while (begin != end) { |
| r = ensure_next_mapping(pool); |
| if (r) |
| /* we did our best */ |
| return; |
| |
| r = dm_thin_find_mapped_range(tc->td, begin, end, &virt_begin, &virt_end, |
| &data_begin, &maybe_shared); |
| if (r) |
| /* |
| * Silently fail, letting any mappings we've |
| * created complete. |
| */ |
| break; |
| |
| build_key(tc->td, PHYSICAL, data_begin, data_begin + (virt_end - virt_begin), &data_key); |
| if (bio_detain(tc->pool, &data_key, NULL, &data_cell)) { |
| /* contention, we'll give up with this range */ |
| begin = virt_end; |
| continue; |
| } |
| |
| /* |
| * 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->maybe_shared = maybe_shared; |
| m->virt_begin = virt_begin; |
| m->virt_end = virt_end; |
| m->data_block = data_begin; |
| m->cell = data_cell; |
| m->bio = bio; |
| |
| /* |
| * The parent bio must not complete before sub discard bios are |
| * chained to it (see end_discard's bio_chain)! |
| * |
| * This per-mapping bi_remaining increment is paired with |
| * the implicit decrement that occurs via bio_endio() in |
| * end_discard(). |
| */ |
| bio_inc_remaining(bio); |
| if (!dm_deferred_set_add_work(pool->all_io_ds, &m->list)) |
| pool->process_prepared_discard(m); |
| |
| begin = virt_end; |
| } |
| } |
| |
| static void process_discard_cell_passdown(struct thin_c *tc, struct dm_bio_prison_cell *virt_cell) |
| { |
| struct bio *bio = virt_cell->holder; |
| struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook)); |
| |
| /* |
| * The virt_cell will only get freed once the origin bio completes. |
| * This means it will remain locked while all the individual |
| * passdown bios are in flight. |
| */ |
| h->cell = virt_cell; |
| break_up_discard_bio(tc, virt_cell->key.block_begin, virt_cell->key.block_end, bio); |
| |
| /* |
| * We complete the bio now, knowing that the bi_remaining field |
| * will prevent completion until the sub range discards have |
| * completed. |
| */ |
| bio_endio(bio); |
| } |
| |
| static void process_discard_bio(struct thin_c *tc, struct bio *bio) |
| { |
| dm_block_t begin, end; |
| struct dm_cell_key virt_key; |
| struct dm_bio_prison_cell *virt_cell; |
| |
| get_bio_block_range(tc, bio, &begin, &end); |
| if (begin == end) { |
| /* |
| * The discard covers less than a block. |
| */ |
| bio_endio(bio); |
| return; |
| } |
| |
| build_key(tc->td, VIRTUAL, begin, end, &virt_key); |
| if (bio_detain(tc->pool, &virt_key, bio, &virt_cell)) |
| /* |
| * Potential starvation issue: We're relying on the |
| * fs/application being well behaved, and not trying to |
| * send IO to a region at the same time as discarding it. |
| * If they do this persistently then it's possible this |
| * cell will never be granted. |
| */ |
| return; |
| |
| tc->pool->process_discard_cell(tc, virt_cell); |
| } |
| |
| static void break_sharing(struct thin_c *tc, struct bio *bio, dm_block_t block, |
| struct dm_cell_key *key, |
| struct dm_thin_lookup_result *lookup_result, |
| struct dm_bio_prison_cell *cell) |
| { |
| int r; |
| dm_block_t data_block; |
| struct pool *pool = tc->pool; |
| |
| 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: |
| retry_bios_on_resume(pool, cell); |
| break; |
| |
| default: |
| DMERR_LIMIT("%s: alloc_data_block() failed: error = %d", |
| __func__, r); |
| cell_error(pool, cell); |
| break; |
| } |
| } |
| |
| static void __remap_and_issue_shared_cell(void *context, |
| struct dm_bio_prison_cell *cell) |
| { |
| struct remap_info *info = context; |
| struct bio *bio; |
| |
| while ((bio = bio_list_pop(&cell->bios))) { |
| if (bio_data_dir(bio) == WRITE || op_is_flush(bio->bi_opf) || |
| bio_op(bio) == REQ_OP_DISCARD) |
| bio_list_add(&info->defer_bios, bio); |
| else { |
| struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));; |
| |
| h->shared_read_entry = dm_deferred_entry_inc(info->tc->pool->shared_read_ds); |
| inc_all_io_entry(info->tc->pool, bio); |
| bio_list_add(&info->issue_bios, bio); |
| } |
| } |
| } |
| |
| static void remap_and_issue_shared_cell(struct thin_c *tc, |
| struct dm_bio_prison_cell *cell, |
| dm_block_t block) |
| { |
| struct bio *bio; |
| struct remap_info info; |
| |
| info.tc = tc; |
| bio_list_init(&info.defer_bios); |
| bio_list_init(&info.issue_bios); |
| |
| cell_visit_release(tc->pool, __remap_and_issue_shared_cell, |
| &info, cell); |
| |
| while ((bio = bio_list_pop(&info.defer_bios))) |
| thin_defer_bio(tc, bio); |
| |
| while ((bio = bio_list_pop(&info.issue_bios))) |
| remap_and_issue(tc, bio, block); |
| } |
| |
| 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 *virt_cell) |
| { |
| struct dm_bio_prison_cell *data_cell; |
| struct pool *pool = tc->pool; |
| struct dm_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, &key, bio, &data_cell)) { |
| cell_defer_no_holder(tc, virt_cell); |
| return; |
| } |
| |
| if (bio_data_dir(bio) == WRITE && bio->bi_iter.bi_size) { |
| break_sharing(tc, bio, block, &key, lookup_result, data_cell); |
| cell_defer_no_holder(tc, virt_cell); |
| } else { |
| struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook)); |
| |
| h->shared_read_entry = dm_deferred_entry_inc(pool->shared_read_ds); |
| inc_all_io_entry(pool, bio); |
| remap_and_issue(tc, bio, lookup_result->block); |
| |
| remap_and_issue_shared_cell(tc, data_cell, lookup_result->block); |
| remap_and_issue_shared_cell(tc, virt_cell, 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; |
| struct pool *pool = tc->pool; |
| |
| /* |
| * Remap empty bios (flushes) immediately, without provisioning. |
| */ |
| if (!bio->bi_iter.bi_size) { |
| inc_all_io_entry(pool, bio); |
| cell_defer_no_holder(tc, cell); |
| |
| 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_defer_no_holder(tc, cell); |
| bio_endio(bio); |
| 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: |
| retry_bios_on_resume(pool, cell); |
| break; |
| |
| default: |
| DMERR_LIMIT("%s: alloc_data_block() failed: error = %d", |
| __func__, r); |
| cell_error(pool, cell); |
| break; |
| } |
| } |
| |
| static void process_cell(struct thin_c *tc, struct dm_bio_prison_cell *cell) |
| { |
| int r; |
| struct pool *pool = tc->pool; |
| struct bio *bio = cell->holder; |
| dm_block_t block = get_bio_block(tc, bio); |
| struct dm_thin_lookup_result lookup_result; |
| |
| if (tc->requeue_mode) { |
| cell_requeue(pool, cell); |
| return; |
| } |
| |
| r = dm_thin_find_block(tc->td, block, 1, &lookup_result); |
| switch (r) { |
| case 0: |
| if (lookup_result.shared) |
| process_shared_bio(tc, bio, block, &lookup_result, cell); |
| else { |
| inc_all_io_entry(pool, bio); |
| remap_and_issue(tc, bio, lookup_result.block); |
| inc_remap_and_issue_cell(tc, cell, lookup_result.block); |
| } |
| break; |
| |
| case -ENODATA: |
| if (bio_data_dir(bio) == READ && tc->origin_dev) { |
| inc_all_io_entry(pool, bio); |
| cell_defer_no_holder(tc, cell); |
| |
| if (bio_end_sector(bio) <= tc->origin_size) |
| remap_to_origin_and_issue(tc, bio); |
| |
| else if (bio->bi_iter.bi_sector < tc->origin_size) { |
| zero_fill_bio(bio); |
| bio->bi_iter.bi_size = (tc->origin_size - bio->bi_iter.bi_sector) << SECTOR_SHIFT; |
| remap_to_origin_and_issue(tc, bio); |
| |
| } else { |
| zero_fill_bio(bio); |
| bio_endio(bio); |
| } |
| } else |
| provision_block(tc, bio, block, cell); |
| break; |
| |
| default: |
| DMERR_LIMIT("%s: dm_thin_find_block() failed: error = %d", |
| __func__, r); |
| cell_defer_no_holder(tc, cell); |
| bio_io_error(bio); |
| break; |
| } |
| } |
| |
| static void process_bio(struct thin_c *tc, struct bio *bio) |
| { |
| struct pool *pool = tc->pool; |
| dm_block_t block = get_bio_block(tc, bio); |
| struct dm_bio_prison_cell *cell; |
| struct dm_cell_key key; |
| |
| /* |
| * 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(pool, &key, bio, &cell)) |
| return; |
| |
| process_cell(tc, cell); |
| } |
| |
| static void __process_bio_read_only(struct thin_c *tc, struct bio *bio, |
| struct dm_bio_prison_cell *cell) |
| { |
| int r; |
| int rw = bio_data_dir(bio); |
| dm_block_t block = get_bio_block(tc, bio); |
| struct dm_thin_lookup_result lookup_result; |
| |
| r = dm_thin_find_block(tc->td, block, 1, &lookup_result); |
| switch (r) { |
| case 0: |
| if (lookup_result.shared && (rw == WRITE) && bio->bi_iter.bi_size) { |
| handle_unserviceable_bio(tc->pool, bio); |
| if (cell) |
| cell_defer_no_holder(tc, cell); |
| } else { |
| inc_all_io_entry(tc->pool, bio); |
| remap_and_issue(tc, bio, lookup_result.block); |
| if (cell) |
| inc_remap_and_issue_cell(tc, cell, lookup_result.block); |
| } |
| break; |
| |
| case -ENODATA: |
| if (cell) |
| cell_defer_no_holder(tc, cell); |
| if (rw != READ) { |
| handle_unserviceable_bio(tc->pool, bio); |
| break; |
| } |
| |
| if (tc->origin_dev) { |
| inc_all_io_entry(tc->pool, bio); |
| remap_to_origin_and_issue(tc, bio); |
| break; |
| } |
| |
| zero_fill_bio(bio); |
| bio_endio(bio); |
| break; |
| |
| default: |
| DMERR_LIMIT("%s: dm_thin_find_block() failed: error = %d", |
| __func__, r); |
| if (cell) |
| cell_defer_no_holder(tc, cell); |
| bio_io_error(bio); |
| break; |
| } |
| } |
| |
| static void process_bio_read_only(struct thin_c *tc, struct bio *bio) |
| { |
| __process_bio_read_only(tc, bio, NULL); |
| } |
| |
| static void process_cell_read_only(struct thin_c *tc, struct dm_bio_prison_cell *cell) |
| { |
| __process_bio_read_only(tc, cell->holder, cell); |
| } |
| |
| static void process_bio_success(struct thin_c *tc, struct bio *bio) |
| { |
| bio_endio(bio); |
| } |
| |
| static void process_bio_fail(struct thin_c *tc, struct bio *bio) |
| { |
| bio_io_error(bio); |
| } |
| |
| static void process_cell_success(struct thin_c *tc, struct dm_bio_prison_cell *cell) |
| { |
| cell_success(tc->pool, cell); |
| } |
| |
| static void process_cell_fail(struct thin_c *tc, struct dm_bio_prison_cell *cell) |
| { |
| cell_error(tc->pool, cell); |
| } |
| |
| /* |
| * FIXME: should we also commit due to size of transaction, measured in |
| * metadata blocks? |
| */ |
| static int need_commit_due_to_time(struct pool *pool) |
| { |
| return !time_in_range(jiffies, pool->last_commit_jiffies, |
| pool->last_commit_jiffies + COMMIT_PERIOD); |
| } |
| |
| #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; |
| unsigned count = 0; |
| |
| if (tc->requeue_mode) { |
| error_thin_bio_list(tc, &tc->deferred_bio_list, DM_ENDIO_REQUEUE); |
| return; |
| } |
| |
| bio_list_init(&bios); |
| |
| spin_lock_irqsave(&tc->lock, flags); |
| |
| if (bio_list_empty(&tc->deferred_bio_list)) { |
| spin_unlock_irqrestore(&tc->lock, flags); |
| return; |
| } |
| |
| __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(&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; |
| } |
| |
| if (bio_op(bio) == REQ_OP_DISCARD) |
| pool->process_discard(tc, bio); |
| else |
| pool->process_bio(tc, bio); |
| |
| if ((count++ & 127) == 0) { |
| throttle_work_update(&pool->throttle); |
| dm_pool_issue_prefetches(pool->pmd); |
| } |
| } |
| blk_finish_plug(&plug); |
| } |
| |
| static int cmp_cells(const void *lhs, const void *rhs) |
| { |
| struct dm_bio_prison_cell *lhs_cell = *((struct dm_bio_prison_cell **) lhs); |
| struct dm_bio_prison_cell *rhs_cell = *((struct dm_bio_prison_cell **) rhs); |
| |
| BUG_ON(!lhs_cell->holder); |
| BUG_ON(!rhs_cell->holder); |
| |
| if (lhs_cell->holder->bi_iter.bi_sector < rhs_cell->holder->bi_iter.bi_sector) |
| return -1; |
| |
| if (lhs_cell->holder->bi_iter.bi_sector > rhs_cell->holder->bi_iter.bi_sector) |
| return 1; |
| |
| return 0; |
| } |
| |
| static unsigned sort_cells(struct pool *pool, struct list_head *cells) |
| { |
| unsigned count = 0; |
| struct dm_bio_prison_cell *cell, *tmp; |
| |
| list_for_each_entry_safe(cell, tmp, cells, user_list) { |
| if (count >= CELL_SORT_ARRAY_SIZE) |
| break; |
| |
| pool->cell_sort_array[count++] = cell; |
| list_del(&cell->user_list); |
| } |
| |
| sort(pool->cell_sort_array, count, sizeof(cell), cmp_cells, NULL); |
| |
| return count; |
| } |
| |
| static void process_thin_deferred_cells(struct thin_c *tc) |
| { |
| struct pool *pool = tc->pool; |
| unsigned long flags; |
| struct list_head cells; |
| struct dm_bio_prison_cell *cell; |
| unsigned i, j, count; |
| |
| INIT_LIST_HEAD(&cells); |
| |
| spin_lock_irqsave(&tc->lock, flags); |
| list_splice_init(&tc->deferred_cells, &cells); |
| spin_unlock_irqrestore(&tc->lock, flags); |
| |
| if (list_empty(&cells)) |
| return; |
| |
| do { |
| count = sort_cells(tc->pool, &cells); |
| |
| for (i = 0; i < count; i++) { |
| cell = pool->cell_sort_array[i]; |
| BUG_ON(!cell->holder); |
| |
| /* |
| * 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)) { |
| for (j = i; j < count; j++) |
| list_add(&pool->cell_sort_array[j]->user_list, &cells); |
| |
| spin_lock_irqsave(&tc->lock, flags); |
| list_splice(&cells, &tc->deferred_cells); |
| spin_unlock_irqrestore(&tc->lock, flags); |
| return; |
| } |
| |
| if (bio_op(cell->holder) == REQ_OP_DISCARD) |
| pool->process_discard_cell(tc, cell); |
| else |
| pool->process_cell(tc, cell); |
| } |
| } while (!list_empty(&cells)); |
| } |
| |
| static void thin_get(struct thin_c *tc); |
| static void thin_put(struct thin_c *tc); |
| |
| /* |
| * We can't hold rcu_read_lock() around code that can block. So we |
| * find a thin with the rcu lock held; bump a refcount; then drop |
| * the lock. |
| */ |
| static struct thin_c *get_first_thin(struct pool *pool) |
| { |
| struct thin_c *tc = NULL; |
| |
| rcu_read_lock(); |
| if (!list_empty(&pool->active_thins)) { |
| tc = list_entry_rcu(pool->active_thins.next, struct thin_c, list); |
| thin_get(tc); |
| } |
| rcu_read_unlock(); |
| |
| return tc; |
| } |
| |
| static struct thin_c *get_next_thin(struct pool *pool, struct thin_c *tc) |
| { |
| struct thin_c *old_tc = tc; |
| |
| rcu_read_lock(); |
| list_for_each_entry_continue_rcu(tc, &pool->active_thins, list) { |
| thin_get(tc); |
| thin_put(old_tc); |
| rcu_read_unlock(); |
| return tc; |
| } |
| thin_put(old_tc); |
| rcu_read_unlock(); |
| |
| return NULL; |
| } |
| |
| static void process_deferred_bios(struct pool *pool) |
| { |
| unsigned long flags; |
| struct bio *bio; |
| struct bio_list bios; |
| struct thin_c *tc; |
| |
| tc = get_first_thin(pool); |
| while (tc) { |
| process_thin_deferred_cells(tc); |
| process_thin_deferred_bios(tc); |
| tc = get_next_thin(pool, tc); |
| } |
| |
| /* |
| * 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) && |
| !(dm_pool_changed_this_transaction(pool->pmd) && need_commit_due_to_time(pool))) |
| return; |
| |
| if (commit(pool)) { |
| 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); |
| |
| throttle_work_start(&pool->throttle); |
| dm_pool_issue_prefetches(pool->pmd); |
| throttle_work_update(&pool->throttle); |
| process_prepared(pool, &pool->prepared_mappings, &pool->process_prepared_mapping); |
| throttle_work_update(&pool->throttle); |
| process_prepared(pool, &pool->prepared_discards, &pool->process_prepared_discard); |
| throttle_work_update(&pool->throttle); |
| process_prepared(pool, &pool->prepared_discards_pt2, &pool->process_prepared_discard_pt2); |
| throttle_work_update(&pool->throttle); |
| process_deferred_bios(pool); |
| throttle_work_complete(&pool->throttle); |
| } |
| |
| /* |
| * 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); |
| } |
| |
| static void notify_of_pool_mode_change_to_oods(struct pool *pool); |
| |
| /* |
| * We're holding onto IO to allow userland time to react. After the |
| * timeout either the pool will have been resized (and thus back in |
| * PM_WRITE mode), or we degrade to PM_OUT_OF_DATA_SPACE w/ error_if_no_space. |
| */ |
| static void do_no_space_timeout(struct work_struct *ws) |
| { |
| struct pool *pool = container_of(to_delayed_work(ws), struct pool, |
| no_space_timeout); |
| |
| if (get_pool_mode(pool) == PM_OUT_OF_DATA_SPACE && !pool->pf.error_if_no_space) { |
| pool->pf.error_if_no_space = true; |
| notify_of_pool_mode_change_to_oods(pool); |
| error_retry_list_with_code(pool, -ENOSPC); |
| } |
| } |
| |
| /*----------------------------------------------------------------*/ |
| |
| struct pool_work { |
| struct work_struct worker; |
| struct completion complete; |
| }; |
| |
| static struct pool_work *to_pool_work(struct work_struct *ws) |
| { |
| return container_of(ws, struct pool_work, worker); |
| } |
| |
| static void pool_work_complete(struct pool_work *pw) |
| { |
| complete(&pw->complete); |
| } |
| |
| static void pool_work_wait(struct pool_work *pw, struct pool *pool, |
| void (*fn)(struct work_struct *)) |
| { |
| INIT_WORK_ONSTACK(&pw->worker, fn); |
| init_completion(&pw->complete); |
| queue_work(pool->wq, &pw->worker); |
| wait_for_completion(&pw->complete); |
| } |
| |
| /*----------------------------------------------------------------*/ |
| |
| struct noflush_work { |
| struct pool_work pw; |
| struct thin_c *tc; |
| }; |
| |
| static struct noflush_work *to_noflush(struct work_struct *ws) |
| { |
| return container_of(to_pool_work(ws), struct noflush_work, pw); |
| } |
| |
| static void do_noflush_start(struct work_struct *ws) |
| { |
| struct noflush_work *w = to_noflush(ws); |
| w->tc->requeue_mode = true; |
| requeue_io(w->tc); |
| pool_work_complete(&w->pw); |
| } |
| |
| static void do_noflush_stop(struct work_struct *ws) |
| { |
| struct noflush_work *w = to_noflush(ws); |
| w->tc->requeue_mode = false; |
| pool_work_complete(&w->pw); |
| } |
| |
| static void noflush_work(struct thin_c *tc, void (*fn)(struct work_struct *)) |
| { |
| struct noflush_work w; |
| |
| w.tc = tc; |
| pool_work_wait(&w.pw, tc->pool, fn); |
| } |
| |
| /*----------------------------------------------------------------*/ |
| |
| static enum pool_mode get_pool_mode(struct pool *pool) |
| { |
| return pool->pf.mode; |
| } |
| |
| static void notify_of_pool_mode_change(struct pool *pool, const char *new_mode) |
| { |
| dm_table_event(pool->ti->table); |
| DMINFO("%s: switching pool to %s mode", |
| dm_device_name(pool->pool_md), new_mode); |
| } |
| |
| static void notify_of_pool_mode_change_to_oods(struct pool *pool) |
| { |
| if (!pool->pf.error_if_no_space) |
| notify_of_pool_mode_change(pool, "out-of-data-space (queue IO)"); |
| else |
| notify_of_pool_mode_change(pool, "out-of-data-space (error IO)"); |
| } |
| |
| static bool passdown_enabled(struct pool_c *pt) |
| { |
| return pt->adjusted_pf.discard_passdown; |
| } |
| |
| static void set_discard_callbacks(struct pool *pool) |
| { |
| struct pool_c *pt = pool->ti->private; |
| |
| if (passdown_enabled(pt)) { |
| pool->process_discard_cell = process_discard_cell_passdown; |
| pool->process_prepared_discard = process_prepared_discard_passdown_pt1; |
| pool->process_prepared_discard_pt2 = process_prepared_discard_passdown_pt2; |
| } else { |
| pool->process_discard_cell = process_discard_cell_no_passdown; |
| pool->process_prepared_discard = process_prepared_discard_no_passdown; |
| } |
| } |
| |
| static void set_pool_mode(struct pool *pool, enum pool_mode new_mode) |
| { |
| struct pool_c *pt = pool->ti->private; |
| bool needs_check = dm_pool_metadata_needs_check(pool->pmd); |
| enum pool_mode old_mode = get_pool_mode(pool); |
| unsigned long no_space_timeout = ACCESS_ONCE(no_space_timeout_secs) * HZ; |
| |
| /* |
| * Never allow the pool to transition to PM_WRITE mode if user |
| * intervention is required to verify metadata and data consistency. |
| */ |
| if (new_mode == PM_WRITE && needs_check) { |
| DMERR("%s: unable to switch pool to write mode until repaired.", |
| dm_device_name(pool->pool_md)); |
| if (old_mode != new_mode) |
| new_mode = old_mode; |
| else |
| new_mode = PM_READ_ONLY; |
| } |
| /* |
| * If we were in PM_FAIL mode, rollback of metadata failed. We're |
| * not going to recover without a thin_repair. So we never let the |
| * pool move out of the old mode. |
| */ |
| if (old_mode == PM_FAIL) |
| new_mode = old_mode; |
| |
| switch (new_mode) { |
| case PM_FAIL: |
| if (old_mode != new_mode) |
| notify_of_pool_mode_change(pool, "failure"); |
| dm_pool_metadata_read_only(pool->pmd); |
| pool->process_bio = process_bio_fail; |
| pool->process_discard = process_bio_fail; |
| pool->process_cell = process_cell_fail; |
| pool->process_discard_cell = process_cell_fail; |
| pool->process_prepared_mapping = process_prepared_mapping_fail; |
| pool->process_prepared_discard = process_prepared_discard_fail; |
| |
| error_retry_list(pool); |
| break; |
| |
| case PM_READ_ONLY: |
| if (old_mode != new_mode) |
| notify_of_pool_mode_change(pool, "read-only"); |
| dm_pool_metadata_read_only(pool->pmd); |
| pool->process_bio = process_bio_read_only; |
| pool->process_discard = process_bio_success; |
| pool->process_cell = process_cell_read_only; |
| pool->process_discard_cell = process_cell_success; |
| pool->process_prepared_mapping = process_prepared_mapping_fail; |
| pool->process_prepared_discard = process_prepared_discard_success; |
| |
| error_retry_list(pool); |
| break; |
| |
| case PM_OUT_OF_DATA_SPACE: |
| /* |
| * Ideally we'd never hit this state; the low water mark |
| * would trigger userland to extend the pool before we |
| * completely run out of data space. However, many small |
| * IOs to unprovisioned space can consume data space at an |
| * alarming rate. Adjust your low water mark if you're |
| * frequently seeing this mode. |
| */ |
| if (old_mode != new_mode) |
| notify_of_pool_mode_change_to_oods(pool); |
| pool->out_of_data_space = true; |
| pool->process_bio = process_bio_read_only; |
| pool->process_discard = process_discard_bio; |
| pool->process_cell = process_cell_read_only; |
| pool->process_prepared_mapping = process_prepared_mapping; |
| set_discard_callbacks(pool); |
| |
| if (!pool->pf.error_if_no_space && no_space_timeout) |
| queue_delayed_work(pool->wq, &pool->no_space_timeout, no_space_timeout); |
| break; |
| |
| case PM_WRITE: |
| if (old_mode != new_mode) |
| notify_of_pool_mode_change(pool, "write"); |
| pool->out_of_data_space = false; |
| pool->pf.error_if_no_space = pt->requested_pf.error_if_no_space; |
| dm_pool_metadata_read_write(pool->pmd); |
| pool->process_bio = process_bio; |
| pool->process_discard = process_discard_bio; |
| pool->process_cell = process_cell; |
| pool->process_prepared_mapping = process_prepared_mapping; |
| set_discard_callbacks(pool); |
| break; |
| } |
| |
| pool->pf.mode = new_mode; |
| /* |
| * The pool mode may have changed, sync it so bind_control_target() |
| * doesn't cause an unexpected mode transition on resume. |
| */ |
| pt->adjusted_pf.mode = new_mode; |
| } |
| |
| static void abort_transaction(struct pool *pool) |
| { |
| const char *dev_name = dm_device_name(pool->pool_md); |
| |
| DMERR_LIMIT("%s: aborting current metadata transaction", dev_name); |
| if (dm_pool_abort_metadata(pool->pmd)) { |
| DMERR("%s: failed to abort metadata transaction", dev_name); |
| set_pool_mode(pool, PM_FAIL); |
| } |
| |
| if (dm_pool_metadata_set_needs_check(pool->pmd)) { |
| DMERR("%s: failed to set 'needs_check' flag in metadata", dev_name); |
| set_pool_mode(pool, PM_FAIL); |
| } |
| } |
| |
| static void metadata_operation_failed(struct pool *pool, const char *op, int r) |
| { |
| DMERR_LIMIT("%s: metadata operation '%s' failed: error = %d", |
| dm_device_name(pool->pool_md), op, r); |
| |
| abort_transaction(pool); |
| set_pool_mode(pool, PM_READ_ONLY); |
| } |
| |
| /*----------------------------------------------------------------*/ |
| |
| /* |
| * 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(&tc->lock, flags); |
| bio_list_add(&tc->deferred_bio_list, bio); |
| spin_unlock_irqrestore(&tc->lock, flags); |
| |
| wake_worker(pool); |
| } |
| |
| static void thin_defer_bio_with_throttle(struct thin_c *tc, struct bio *bio) |
| { |
| struct pool *pool = tc->pool; |
| |
| throttle_lock(&pool->throttle); |
| thin_defer_bio(tc, bio); |
| throttle_unlock(&pool->throttle); |
| } |
| |
| static void thin_defer_cell(struct thin_c *tc, struct dm_bio_prison_cell *cell) |
| { |
| unsigned long flags; |
| struct pool *pool = tc->pool; |
| |
| throttle_lock(&pool->throttle); |
| spin_lock_irqsave(&tc->lock, flags); |
| list_add_tail(&cell->user_list, &tc->deferred_cells); |
| spin_unlock_irqrestore(&tc->lock, flags); |
| throttle_unlock(&pool->throttle); |
| |
| wake_worker(pool); |
| } |
| |
| static void thin_hook_bio(struct thin_c *tc, struct bio *bio) |
| { |
| struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook)); |
| |
| h->tc = tc; |
| h->shared_read_entry = NULL; |
| h->all_io_entry = NULL; |
| h->overwrite_mapping = NULL; |
| h->cell = NULL; |
| } |
| |
| /* |
| * Non-blocking function called from the thin target's map function. |
| */ |
| static int thin_bio_map(struct dm_target *ti, struct bio *bio) |
| { |
| 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; |
| struct dm_bio_prison_cell *virt_cell, *data_cell; |
| struct dm_cell_key key; |
| |
| thin_hook_bio(tc, bio); |
| |
| if (tc->requeue_mode) { |
| bio->bi_error = DM_ENDIO_REQUEUE; |
| bio_endio(bio); |
| return DM_MAPIO_SUBMITTED; |
| } |
| |
| if (get_pool_mode(tc->pool) == PM_FAIL) { |
| bio_io_error(bio); |
| return DM_MAPIO_SUBMITTED; |
| } |
| |
| if (op_is_flush(bio->bi_opf) || bio_op(bio) == REQ_OP_DISCARD) { |
| thin_defer_bio_with_throttle(tc, bio); |
| return DM_MAPIO_SUBMITTED; |
| } |
| |
| /* |
| * We must hold the virtual cell before doing the lookup, otherwise |
| * there's a race with discard. |
| */ |
| build_virtual_key(tc->td, block, &key); |
| if (bio_detain(tc->pool, &key, bio, &virt_cell)) |
| 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_cell(tc, virt_cell); |
| return DM_MAPIO_SUBMITTED; |
| } |
| |
| build_data_key(tc->td, result.block, &key); |
| if (bio_detain(tc->pool, &key, bio, &data_cell)) { |
| cell_defer_no_holder(tc, virt_cell); |
| return DM_MAPIO_SUBMITTED; |
| } |
| |
| inc_all_io_entry(tc->pool, bio); |
| cell_defer_no_holder(tc, data_cell); |
| cell_defer_no_holder(tc, virt_cell); |
| |
| remap(tc, bio, result.block); |
| return DM_MAPIO_REMAPPED; |
| |
| case -ENODATA: |
| case -EWOULDBLOCK: |
| thin_defer_cell(tc, virt_cell); |
| return DM_MAPIO_SUBMITTED; |
| |
| default: |
| /* |
| * Must always call bio_io_error on failure. |
| * dm_thin_find_block can fail with -EINVAL if the |
| * pool is switched to fail-io mode. |
| */ |
| bio_io_error(bio); |
| cell_defer_no_holder(tc, virt_cell); |
| return DM_MAPIO_SUBMITTED; |
| } |
| } |
| |
| static int pool_is_congested(struct dm_target_callbacks *cb, int bdi_bits) |
| { |
| struct pool_c *pt = container_of(cb, struct pool_c, callbacks); |
| struct request_queue *q; |
| |
| if (get_pool_mode(pt->pool) == PM_OUT_OF_DATA_SPACE) |
| return 1; |
| |
| q = bdev_get_queue(pt->data_dev->bdev); |
| return bdi_congested(q->backing_dev_info, bdi_bits); |
| } |
| |
| static void requeue_bios(struct pool *pool) |
| { |
| 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(); |
| } |
| |
| /*---------------------------------------------------------------- |
| * Binding of control targets to a pool object |
| *--------------------------------------------------------------*/ |
| static bool data_dev_supports_discard(struct pool_c *pt) |
| { |
| struct request_queue *q = bdev_get_queue(pt->data_dev->bdev); |
| |
| return q && blk_queue_discard(q); |
| } |
| |
| static bool is_factor(sector_t block_size, uint32_t n) |
| { |
| return !sector_div(block_size, n); |
| } |
| |
| /* |
| * If discard_passdown was enabled verify that the data device |
| * supports discards. Disable discard_passdown if not. |
| */ |
| static void disable_passdown_if_not_supported(struct pool_c *pt) |
| { |
| struct pool *pool = pt->pool; |
| struct block_device *data_bdev = pt->data_dev->bdev; |
| struct queue_limits *data_limits = &bdev_get_queue(data_bdev)->limits; |
| const char *reason = NULL; |
| char buf[BDEVNAME_SIZE]; |
| |
| if (!pt->adjusted_pf.discard_passdown) |
| return; |
| |
| if (!data_dev_supports_discard(pt)) |
| reason = "discard unsupported"; |
| |
| else if (data_limits->max_discard_sectors < pool->sectors_per_block) |
| reason = "max discard sectors smaller than a block"; |
| |
| if (reason) { |
| DMWARN("Data device (%s) %s: Disabling discard passdown.", bdevname(data_bdev, buf), reason); |
| pt->adjusted_pf.discard_passdown = false; |
| } |
| } |
| |
| static int bind_control_target(struct pool *pool, struct dm_target *ti) |
| { |
| struct pool_c *pt = ti->private; |
| |
| /* |
| * We want to make sure that a pool in PM_FAIL mode is never upgraded. |
| */ |
| enum pool_mode old_mode = get_pool_mode(pool); |
| enum pool_mode new_mode = pt->adjusted_pf.mode; |
| |
| /* |
| * Don't change the pool's mode until set_pool_mode() below. |
| * Otherwise the pool's process_* function pointers may |
| * not match the desired pool mode. |
| */ |
| pt->adjusted_pf.mode = old_mode; |
| |
| pool->ti = ti; |
| pool->pf = pt->adjusted_pf; |
| pool->low_water_blocks = pt->low_water_blocks; |
| |
| set_pool_mode(pool, new_mode); |
| |
| 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->mode = PM_WRITE; |
| pf->zero_new_blocks = true; |
| pf->discard_enabled = true; |
| pf->discard_passdown = true; |
| pf->error_if_no_space = false; |
| } |
| |
| static void __pool_destroy(struct pool *pool) |
| { |
| __pool_table_remove(pool); |
| |
| vfree(pool->cell_sort_array); |
| if (dm_pool_metadata_close(pool->pmd) < 0) |
| DMWARN("%s: dm_pool_metadata_close() failed.", __func__); |
| |
| dm_bio_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); |
| dm_deferred_set_destroy(pool->shared_read_ds); |
| dm_deferred_set_destroy(pool->all_io_ds); |
| kfree(pool); |
| } |
| |
| static struct kmem_cache *_new_mapping_cache; |
| |
| static struct pool *pool_create(struct mapped_device *pool_md, |
| struct block_device *metadata_dev, |
| unsigned long block_size, |
| int read_only, char **error) |
| { |
| int r; |
| void *err_p; |
| struct pool *pool; |
| struct dm_pool_metadata *pmd; |
| bool format_device = read_only ? false : true; |
| |
| pmd = dm_pool_metadata_open(metadata_dev, block_size, format_device); |
| 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 = dm_bio_prison_create(); |
| if (!pool->prison) { |
| *error = "Error creating pool's bio prison"; |
| err_p = ERR_PTR(-ENOMEM); |
| goto bad_prison; |
| } |
| |
| pool->copier = dm_kcopyd_client_create(&dm_kcopyd_throttle); |
| 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; |
| } |
| |
| throttle_init(&pool->throttle); |
| INIT_WORK(&pool->worker, do_worker); |
| INIT_DELAYED_WORK(&pool->waker, do_waker); |
| INIT_DELAYED_WORK(&pool->no_space_timeout, do_no_space_timeout); |
| spin_lock_init(&pool->lock); |
| bio_list_init(&pool->deferred_flush_bios); |
| INIT_LIST_HEAD(&pool->prepared_mappings); |
| INIT_LIST_HEAD(&pool->prepared_discards); |
| INIT_LIST_HEAD(&pool->prepared_discards_pt2); |
| INIT_LIST_HEAD(&pool->active_thins); |
| pool->low_water_triggered = false; |
| pool->suspended = true; |
| pool->out_of_data_space = false; |
| |
| pool->shared_read_ds = dm_deferred_set_create(); |
| if (!pool->shared_read_ds) { |
| *error = "Error creating pool's shared read deferred set"; |
| err_p = ERR_PTR(-ENOMEM); |
| goto bad_shared_read_ds; |
| } |
| |
| pool->all_io_ds = dm_deferred_set_create(); |
| if (!pool->all_io_ds) { |
| *error = "Error creating pool's all io deferred set"; |
| err_p = ERR_PTR(-ENOMEM); |
| goto bad_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->cell_sort_array = vmalloc(sizeof(*pool->cell_sort_array) * CELL_SORT_ARRAY_SIZE); |
| if (!pool->cell_sort_array) { |
| *error = "Error allocating cell sort array"; |
| err_p = ERR_PTR(-ENOMEM); |
| goto bad_sort_array; |
| } |
| |
| 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_sort_array: |
| mempool_destroy(pool->mapping_pool); |
| bad_mapping_pool: |
| dm_deferred_set_destroy(pool->all_io_ds); |
| bad_all_io_ds: |
| dm_deferred_set_destroy(pool->shared_read_ds); |
| bad_shared_read_ds: |
| destroy_workqueue(pool->wq); |
| bad_wq: |
| dm_kcopyd_client_destroy(pool->copier); |
| bad_kcopyd_client: |
| dm_bio_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, int read_only, |
| 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, read_only, 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, 4, "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 = false; |
| |
| else if (!strcasecmp(arg_name, "ignore_discard")) |
| pf->discard_enabled = false; |
| |
| else if (!strcasecmp(arg_name, "no_discard_passdown")) |
| pf->discard_passdown = false; |
| |
| else if (!strcasecmp(arg_name, "read_only")) |
| pf->mode = PM_READ_ONLY; |
| |
| else if (!strcasecmp(arg_name, "error_if_no_space")) |
| pf->error_if_no_space = true; |
| |
| else { |
| ti->error = "Unrecognised pool feature requested"; |
| r = -EINVAL; |
| break; |
| } |
| } |
| |
| return r; |
| } |
| |
| static void metadata_low_callback(void *context) |
| { |
| struct pool *pool = context; |
| |
| DMWARN("%s: reached low water mark for metadata device: sending event.", |
| dm_device_name(pool->pool_md)); |
| |
| dm_table_event(pool->ti->table); |
| } |
| |
| static sector_t get_dev_size(struct block_device *bdev) |
| { |
| return i_size_read(bdev->bd_inode) >> SECTOR_SHIFT; |
| } |
| |
| static void warn_if_metadata_device_too_big(struct block_device *bdev) |
| { |
| sector_t metadata_dev_size = get_dev_size(bdev); |
| char buffer[BDEVNAME_SIZE]; |
| |
| 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(bdev, buffer), THIN_METADATA_MAX_SECTORS); |
| } |
| |
| static sector_t get_metadata_dev_size(struct block_device *bdev) |
| { |
| sector_t metadata_dev_size = get_dev_size(bdev); |
| |
| if (metadata_dev_size > THIN_METADATA_MAX_SECTORS) |
| metadata_dev_size = THIN_METADATA_MAX_SECTORS; |
| |
| return metadata_dev_size; |
| } |
| |
| static dm_block_t get_metadata_dev_size_in_blocks(struct block_device *bdev) |
| { |
| sector_t metadata_dev_size = get_metadata_dev_size(bdev); |
| |
| sector_div(metadata_dev_size, THIN_METADATA_BLOCK_SIZE); |
| |
| return metadata_dev_size; |
| } |
| |
| /* |
| * When a metadata threshold is crossed a dm event is triggered, and |
| * userland should respond by growing the metadata device. We could let |
| * userland set the threshold, like we do with the data threshold, but I'm |
| * not sure they know enough to do this well. |
| */ |
| static dm_block_t calc_metadata_threshold(struct pool_c *pt) |
| { |
| /* |
| * 4M is ample for all ops with the possible exception of thin |
| * device deletion which is harmless if it fails (just retry the |
| * delete after you've grown the device). |
| */ |
| dm_block_t quarter = get_metadata_dev_size_in_blocks(pt->metadata_dev->bdev) / 4; |
| return min((dm_block_t)1024ULL /* 4M */, quarter); |
| } |
| |
| /* |
| * 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 |
| * read_only: Don't allow any changes to be made to the pool metadata. |
| * error_if_no_space: error IOs, instead of queueing, if no space. |
| */ |
| 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; |
| fmode_t metadata_mode; |
| |
| /* |
| * 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; |
| |
| /* |
| * Set default pool features. |
| */ |
| pool_features_init(&pf); |
| |
| dm_consume_args(&as, 4); |
| r = parse_pool_features(&as, &pf, ti); |
| if (r) |
| goto out_unlock; |
| |
| metadata_mode = FMODE_READ | ((pf.mode == PM_READ_ONLY) ? 0 : FMODE_WRITE); |
| r = dm_get_device(ti, argv[0], metadata_mode, &metadata_dev); |
| if (r) { |
| ti->error = "Error opening metadata block device"; |
| goto out_unlock; |
| } |
| warn_if_metadata_device_too_big(metadata_dev->bdev); |
| |
| 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; |
| } |
| |
| 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, pf.mode == PM_READ_ONLY, &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; |
| } |
| |
| pt->pool = pool; |
| pt->ti = ti; |
| pt->metadata_dev = metadata_dev; |
| pt->data_dev = data_dev; |
| pt->low_water_blocks = low_water_blocks; |
| pt->adjusted_pf = pt->requested_pf = pf; |
| ti->num_flush_bios = 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. |
| */ |
| ti->discard_zeroes_data_unsupported = true; |
| if (pf.discard_enabled && pf.discard_passdown) { |
| ti->num_discard_bios = 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; |
| |
| r = dm_pool_register_metadata_threshold(pt->pool->pmd, |
| calc_metadata_threshold(pt), |
| metadata_low_callback, |
| pool); |
| if (r) |
| goto out_flags_changed; |
| |
| 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) |
| { |
| 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; |
| } |
| |
| static int maybe_resize_data_dev(struct dm_target *ti, bool *need_commit) |
| { |
| 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; |
| |
| *need_commit = false; |
| |
| (void) sector_div(data_size, pool->sectors_per_block); |
| |
| r = dm_pool_get_data_dev_size(pool->pmd, &sb_data_size); |
| if (r) { |
| DMERR("%s: failed to retrieve data device size", |
| dm_device_name(pool->pool_md)); |
| return r; |
| } |
| |
| if (data_size < sb_data_size) { |
| DMERR("%s: pool target (%llu blocks) too small: expected %llu", |
| dm_device_name(pool->pool_md), |
| (unsigned long long)data_size, sb_data_size); |
| return -EINVAL; |
| |
| } else if (data_size > sb_data_size) { |
| if (dm_pool_metadata_needs_check(pool->pmd)) { |
| DMERR("%s: unable to grow the data device until repaired.", |
| dm_device_name(pool->pool_md)); |
| return 0; |
| } |
| |
| if (sb_data_size) |
| DMINFO("%s: growing the data device from %llu to %llu blocks", |
| dm_device_name(pool->pool_md), |
| sb_data_size, (unsigned long long)data_size); |
| r = dm_pool_resize_data_dev(pool->pmd, data_size); |
| if (r) { |
| metadata_operation_failed(pool, "dm_pool_resize_data_dev", r); |
| return r; |
| } |
| |
| *need_commit = true; |
| } |
| |
| return 0; |
| } |
| |
| static int maybe_resize_metadata_dev(struct dm_target *ti, bool *need_commit) |
| { |
| int r; |
| struct pool_c *pt = ti->private; |
| struct pool *pool = pt->pool; |
| dm_block_t metadata_dev_size, sb_metadata_dev_size; |
| |
| *need_commit = false; |
| |
| metadata_dev_size = get_metadata_dev_size_in_blocks(pool->md_dev); |
| |
| r = dm_pool_get_metadata_dev_size(pool->pmd, &sb_metadata_dev_size); |
| if (r) { |
| DMERR("%s: failed to retrieve metadata device size", |
| dm_device_name(pool->pool_md)); |
| return r; |
| } |
| |
| if (metadata_dev_size < sb_metadata_dev_size) { |
| DMERR("%s: metadata device (%llu blocks) too small: expected %llu", |
| dm_device_name(pool->pool_md), |
| metadata_dev_size, sb_metadata_dev_size); |
| return -EINVAL; |
| |
| } else if (metadata_dev_size > sb_metadata_dev_size) { |
| if (dm_pool_metadata_needs_check(pool->pmd)) { |
| DMERR("%s: unable to grow the metadata device until repaired.", |
| dm_device_name(pool->pool_md)); |
| return 0; |
| } |
| |
| warn_if_metadata_device_too_big(pool->md_dev); |
| DMINFO("%s: growing the metadata device from %llu to %llu blocks", |
| dm_device_name(pool->pool_md), |
| sb_metadata_dev_size, metadata_dev_size); |
| r = dm_pool_resize_metadata_dev(pool->pmd, metadata_dev_size); |
| if (r) { |
| metadata_operation_failed(pool, "dm_pool_resize_metadata_dev", r); |
| return r; |
| } |
| |
| *need_commit = true; |
| } |
| |
| return 0; |
| } |
| |
| /* |
| * 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; |
| bool need_commit1, need_commit2; |
| struct pool_c *pt = ti->private; |
| struct pool *pool = pt->pool; |
| |
| /* |
| * Take control of the pool object. |
| */ |
| r = bind_control_target(pool, ti); |
| if (r) |
| return r; |
| |
| r = maybe_resize_data_dev(ti, &need_commit1); |
| if (r) |
| return r; |
| |
| r = maybe_resize_metadata_dev(ti, &need_commit2); |
| if (r) |
| return r; |
| |
| if (need_commit1 || need_commit2) |
| (void) commit(pool); |
| |
| return 0; |
| } |
| |
| static void pool_suspend_active_thins(struct pool *pool) |
| { |
| struct thin_c *tc; |
| |
| /* Suspend all active thin devices */ |
| tc = get_first_thin(pool); |
| while (tc) { |
| dm_internal_suspend_noflush(tc->thin_md); |
| tc = get_next_thin(pool, tc); |
| } |
| } |
| |
| static void pool_resume_active_thins(struct pool *pool) |
| { |
| struct thin_c *tc; |
| |
| /* Resume all active thin devices */ |
| tc = get_first_thin(pool); |
| while (tc) { |
| dm_internal_resume(tc->thin_md); |
| tc = get_next_thin(pool, tc); |
| } |
| } |
| |
| static void pool_resume(struct dm_target *ti) |
| { |
| struct pool_c *pt = ti->private; |
| struct pool *pool = pt->pool; |
| unsigned long flags; |
| |
| /* |
| * Must requeue active_thins' bios and then resume |
| * active_thins _before_ clearing 'suspend' flag. |
| */ |
| requeue_bios(pool); |
| pool_resume_active_thins(pool); |
| |
| spin_lock_irqsave(&pool->lock, flags); |
| pool->low_water_triggered = false; |
| pool->suspended = false; |
| spin_unlock_irqrestore(&pool->lock, flags); |
| |
| do_waker(&pool->waker.work); |
| } |
| |
| static void pool_presuspend(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->suspended = true; |
| spin_unlock_irqrestore(&pool->lock, flags); |
| |
| pool_suspend_active_thins(pool); |
| } |
| |
| static void pool_presuspend_undo(struct dm_target *ti) |
| { |
| struct pool_c *pt = ti->private; |
| struct pool *pool = pt->pool; |
| unsigned long flags; |
| |
| pool_resume_active_thins(pool); |
| |
| spin_lock_irqsave(&pool->lock, flags); |
| pool->suspended = false; |
| spin_unlock_irqrestore(&pool->lock, flags); |
| } |
| |
| static void pool_postsuspend(struct dm_target *ti) |
| { |
| struct pool_c *pt = ti->private; |
| struct pool *pool = pt->pool; |
| |
| cancel_delayed_work_sync(&pool->waker); |
| cancel_delayed_work_sync(&pool->no_space_timeout); |
| flush_workqueue(pool->wq); |
| (void) commit(pool); |
| } |
| |
| 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; |
| |
| (void) commit(pool); |
| |
| 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> |
| * 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 (get_pool_mode(pool) >= PM_READ_ONLY) { |
| DMERR("%s: unable to service pool target messages in READ_ONLY or FAIL mode", |
| dm_device_name(pool->pool_md)); |
| return -EOPNOTSUPP; |
| } |
| |
| 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) |
| (void) commit(pool); |
| |
| return r; |
| } |
| |
| static void emit_flags(struct pool_features *pf, char *result, |
| unsigned sz, unsigned maxlen) |
| { |
| unsigned count = !pf->zero_new_blocks + !pf->discard_enabled + |
| !pf->discard_passdown + (pf->mode == PM_READ_ONLY) + |
| pf->error_if_no_space; |
| DMEMIT("%u ", count); |
| |
| if (!pf->zero_new_blocks) |
| DMEMIT("skip_block_zeroing "); |
| |
| if (!pf->discard_enabled) |
| DMEMIT("ignore_discard "); |
| |
| if (!pf->discard_passdown) |
| DMEMIT("no_discard_passdown "); |
| |
| if (pf->mode == PM_READ_ONLY) |
| DMEMIT("read_only "); |
| |
| if (pf->error_if_no_space) |
| DMEMIT("error_if_no_space "); |
| } |
| |
| /* |
| * Status line is: |
| * <transaction id> <used metadata sectors>/<total metadata sectors> |
| * <used data sectors>/<total data sectors> <held metadata root> |
| * <pool mode> <discard config> <no space config> <needs_check> |
| */ |
| static void pool_status(struct dm_target *ti, status_type_t type, |
| unsigned status_flags, char *result, unsigned maxlen) |
| { |
| int r; |
| 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: |
| if (get_pool_mode(pool) == PM_FAIL) { |
| DMEMIT("Fail"); |
| break; |
| } |
| |
| /* Commit to ensure statistics aren't out-of-date */ |
| if (!(status_flags & DM_STATUS_NOFLUSH_FLAG) && !dm_suspended(ti)) |
| (void) commit(pool); |
| |
| r = dm_pool_get_metadata_transaction_id(pool->pmd, &transaction_id); |
| if (r) { |
| DMERR("%s: dm_pool_get_metadata_transaction_id returned %d", |
| dm_device_name(pool->pool_md), r); |
| goto err; |
| } |
| |
| r = dm_pool_get_free_metadata_block_count(pool->pmd, &nr_free_blocks_metadata); |
| if (r) { |
| DMERR("%s: dm_pool_get_free_metadata_block_count returned %d", |
| dm_device_name(pool->pool_md), r); |
| goto err; |
| } |
| |
| r = dm_pool_get_metadata_dev_size(pool->pmd, &nr_blocks_metadata); |
| if (r) { |
| DMERR("%s: dm_pool_get_metadata_dev_size returned %d", |
| dm_device_name(pool->pool_md), r); |
| goto err; |
| } |
| |
| r = dm_pool_get_free_block_count(pool->pmd, &nr_free_blocks_data); |
| if (r) { |
| DMERR("%s: dm_pool_get_free_block_count returned %d", |
| dm_device_name(pool->pool_md), r); |
| goto err; |
| } |
| |
| r = dm_pool_get_data_dev_size(pool->pmd, &nr_blocks_data); |
| if (r) { |
| DMERR("%s: dm_pool_get_data_dev_size returned %d", |
| dm_device_name(pool->pool_md), r); |
| goto err; |
| } |
| |
| r = dm_pool_get_metadata_snap(pool->pmd, &held_root); |
| if (r) { |
| DMERR("%s: dm_pool_get_metadata_snap returned %d", |
| dm_device_name(pool->pool_md), r); |
| goto err; |
| } |
| |
| 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("- "); |
| |
| if (pool->pf.mode == PM_OUT_OF_DATA_SPACE) |
| DMEMIT("out_of_data_space "); |
| else if (pool->pf.mode == PM_READ_ONLY) |
| DMEMIT("ro "); |
| else |
| DMEMIT("rw "); |
| |
| if (!pool->pf.discard_enabled) |
| DMEMIT("ignore_discard "); |
| else if (pool->pf.discard_passdown) |
| DMEMIT("discard_passdown "); |
| else |
| DMEMIT("no_discard_passdown "); |
| |
| if (pool->pf.error_if_no_space) |
| DMEMIT("error_if_no_space "); |
| else |
| DMEMIT("queue_if_no_space "); |
| |
| if (dm_pool_metadata_needs_check(pool->pmd)) |
| DMEMIT("needs_check "); |
| 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); |
| emit_flags(&pt->requested_pf, result, sz, maxlen); |
| break; |
| } |
| return; |
| |
| err: |
| DMEMIT("Error"); |
| } |
| |
| 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 void pool_io_hints(struct dm_target *ti, struct queue_limits *limits) |
| { |
| struct pool_c *pt = ti->private; |
| struct pool *pool = pt->pool; |
| sector_t io_opt_sectors = limits->io_opt >> SECTOR_SHIFT; |
| |
| /* |
| * If max_sectors is smaller than pool->sectors_per_block adjust it |
| * to the highest possible power-of-2 factor of pool->sectors_per_block. |
| * This is especially beneficial when the pool's data device is a RAID |
| * device that has a full stripe width that matches pool->sectors_per_block |
| * -- because even though partial RAID stripe-sized IOs will be issued to a |
| * single RAID stripe; when aggregated they will end on a full RAID stripe |
| * boundary.. which avoids additional partial RAID stripe writes cascading |
| */ |
| if (limits->max_sectors < pool->sectors_per_block) { |
| while (!is_factor(pool->sectors_per_block, limits->max_sectors)) { |
| if ((limits->max_sectors & (limits->max_sectors - 1)) == 0) |
| limits->max_sectors--; |
| limits->max_sectors = rounddown_pow_of_two(limits->max_sectors); |
| } |
| } |
| |
| /* |
| * If the system-determined stacked limits are compatible with the |
| * pool's blocksize (io_opt is a factor) do not override them. |
| */ |
| if (io_opt_sectors < pool->sectors_per_block || |
| !is_factor(io_opt_sectors, pool->sectors_per_block)) { |
| if (is_factor(pool->sectors_per_block, limits->max_sectors)) |
| blk_limits_io_min(limits, limits->max_sectors << SECTOR_SHIFT); |
| else |
| blk_limits_io_min(limits, pool->sectors_per_block << SECTOR_SHIFT); |
| blk_limits_io_opt(limits, pool->sectors_per_block << SECTOR_SHIFT); |
| } |
| |
| /* |
| * pt->adjusted_pf is a staging area for the actual features to use. |
| * They get transferred to the live pool in bind_control_target() |
| * called from pool_preresume(). |
| */ |
| if (!pt->adjusted_pf.discard_enabled) { |
| /* |
| * Must explicitly disallow stacking discard limits otherwise the |
| * block layer will stack them if pool's data device has support. |
| * QUEUE_FLAG_DISCARD wouldn't be set but there is no way for the |
| * user to see that, so make sure to set all discard limits to 0. |
| */ |
| limits->discard_granularity = 0; |
| return; |
| } |
| |
| disable_passdown_if_not_supported(pt); |
| |
| /* |
| * The pool uses the same discard limits as the underlying data |
| * device. DM core has already set this up. |
| */ |
| } |
| |
| static struct target_type pool_target = { |
| .name = "thin-pool", |
| .features = DM_TARGET_SINGLETON | DM_TARGET_ALWAYS_WRITEABLE | |
| DM_TARGET_IMMUTABLE, |
| .version = {1, 19, 0}, |
| .module = THIS_MODULE, |
| .ctr = pool_ctr, |
| .dtr = pool_dtr, |
| .map = pool_map, |
| .presuspend = pool_presuspend, |
| .presuspend_undo = pool_presuspend_undo, |
| .postsuspend = pool_postsuspend, |
| .preresume = pool_preresume, |
| .resume = pool_resume, |
| .message = pool_message, |
| .status = pool_status, |
| .iterate_devices = pool_iterate_devices, |
| .io_hints = pool_io_hints, |
| }; |
| |
| /*---------------------------------------------------------------- |
| * Thin target methods |
| *--------------------------------------------------------------*/ |
| static void thin_get(struct thin_c *tc) |
| { |
| atomic_inc(&tc->refcount); |
| } |
| |
| static void thin_put(struct thin_c *tc) |
| { |
| if (atomic_dec_and_test(&tc->refcount)) |
| complete(&tc->can_destroy); |
| } |
| |
| 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(); |
| |
| thin_put(tc); |
| wait_for_completion(&tc->can_destroy); |
| |
| 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; |
| unsigned long flags; |
| |
| 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; |
| } |
| tc->thin_md = dm_table_get_md(ti->table); |
| spin_lock_init(&tc->lock); |
| INIT_LIST_HEAD(&tc->deferred_cells); |
| 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); |
| 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); |
| |
| if (get_pool_mode(tc->pool) == PM_FAIL) { |
| ti->error = "Couldn't open thin device, Pool is in fail mode"; |
| r = -EINVAL; |
| goto bad_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_pool; |
| } |
| |
| r = dm_set_target_max_io_len(ti, tc->pool->sectors_per_block); |
| if (r) |
| goto bad; |
| |
| ti->num_flush_bios = 1; |
| ti->flush_supported = true; |
| ti->per_io_data_size = sizeof(struct dm_thin_endio_hook); |
| |
| /* In case the pool supports discards, pass them on. */ |
| ti->discard_zeroes_data_unsupported = true; |
| if (tc->pool->pf.discard_enabled) { |
| ti->discards_supported = true; |
| ti->num_discard_bios = 1; |
| ti->split_discard_bios = false; |
| } |
| |
| mutex_unlock(&dm_thin_pool_table.mutex); |
| |
| spin_lock_irqsave(&tc->pool->lock, flags); |
| if (tc->pool->suspended) { |
| spin_unlock_irqrestore(&tc->pool->lock, flags); |
| mutex_lock(&dm_thin_pool_table.mutex); /* reacquire for __pool_dec */ |
| ti->error = "Unable to activate thin device while pool is suspended"; |
| r = -EINVAL; |
| goto bad; |
| } |
| atomic_set(&tc->refcount, 1); |
| init_completion(&tc->can_destroy); |
| list_add_tail_rcu(&tc->list, &tc->pool->active_thins); |
| spin_unlock_irqrestore(&tc->pool->lock, flags); |
| /* |
| * 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(); |
| |
| dm_put(pool_md); |
| |
| return 0; |
| |
| bad: |
| dm_pool_close_thin_device(tc->td); |
| bad_pool: |
| __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) |
| { |
| bio->bi_iter.bi_sector = dm_target_offset(ti, bio->bi_iter.bi_sector); |
| |
| return thin_bio_map(ti, bio); |
| } |
| |
| static int thin_endio(struct dm_target *ti, struct bio *bio, int err) |
| { |
| unsigned long flags; |
| struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook)); |
| 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); |
| dm_deferred_entry_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); |
| __complete_mapping_preparation(m); |
| } |
| spin_unlock_irqrestore(&pool->lock, flags); |
| } |
| |
| if (h->all_io_entry) { |
| INIT_LIST_HEAD(&work); |
| dm_deferred_entry_dec(h->all_io_entry, &work); |
| if (!list_empty(&work)) { |
| spin_lock_irqsave(&pool->lock, flags); |
| list_for_each_entry_safe(m, tmp, &work, list) |
| list_add_tail(&m->list, &pool->prepared_discards); |
| spin_unlock_irqrestore(&pool->lock, flags); |
| wake_worker(pool); |
| } |
| } |
| |
| if (h->cell) |
| cell_defer_no_holder(h->tc, h->cell); |
| |
| return 0; |
| } |
| |
| static void thin_presuspend(struct dm_target *ti) |
| { |
| struct thin_c *tc = ti->private; |
| |
| if (dm_noflush_suspending(ti)) |
| noflush_work(tc, do_noflush_start); |
| } |
| |
| static void thin_postsuspend(struct dm_target *ti) |
| { |
| struct thin_c *tc = ti->private; |
| |
| /* |
| * The dm_noflush_suspending flag has been cleared by now, so |
| * unfortunately we must always run this. |
| */ |
| noflush_work(tc, do_noflush_stop); |
| } |
| |
| static int thin_preresume(struct dm_target *ti) |
| { |
| struct thin_c *tc = ti->private; |
| |
| if (tc->origin_dev) |
| tc->origin_size = get_dev_size(tc->origin_dev->bdev); |
| |
| return 0; |
| } |
| |
| /* |
| * <nr mapped sectors> <highest mapped sector> |
| */ |
| static void thin_status(struct dm_target *ti, status_type_t type, |
| unsigned status_flags, 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 (get_pool_mode(tc->pool) == PM_FAIL) { |
| DMEMIT("Fail"); |
| return; |
| } |
| |
| if (!tc->td) |
| DMEMIT("-"); |
| else { |
| switch (type) { |
| case STATUSTYPE_INFO: |
| r = dm_thin_get_mapped_count(tc->td, &mapped); |
| if (r) { |
| DMERR("dm_thin_get_mapped_count returned %d", r); |
| goto err; |
| } |
| |
| r = dm_thin_get_highest_mapped_block(tc->td, &highest); |
| if (r < 0) { |
| DMERR("dm_thin_get_highest_mapped_block returned %d", r); |
| goto err; |
| } |
| |
| 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; |
| |
| err: |
| DMEMIT("Error"); |
| } |
| |
| 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; |
| |
| if (!pool->pf.discard_enabled) |
| return; |
| |
| limits->discard_granularity = pool->sectors_per_block << SECTOR_SHIFT; |
| limits->max_discard_sectors = 2048 * 1024 * 16; /* 16G */ |
| } |
| |
| static struct target_type thin_target = { |
| .name = "thin", |
| .version = {1, 19, 0}, |
| .module = THIS_MODULE, |
| .ctr = thin_ctr, |
| .dtr = thin_dtr, |
| .map = thin_map, |
| .end_io = thin_endio, |
| .preresume = thin_preresume, |
| .presuspend = thin_presuspend, |
| .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; |
| |
| _new_mapping_cache = KMEM_CACHE(dm_thin_new_mapping, 0); |
| if (!_new_mapping_cache) |
| goto bad_new_mapping_cache; |
| |
| return 0; |
| |
| bad_new_mapping_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(_new_mapping_cache); |
| } |
| |
| module_init(dm_thin_init); |
| module_exit(dm_thin_exit); |
| |
| module_param_named(no_space_timeout, no_space_timeout_secs, uint, S_IRUGO | S_IWUSR); |
| MODULE_PARM_DESC(no_space_timeout, "Out of data space queue IO timeout in seconds"); |
| |
| MODULE_DESCRIPTION(DM_NAME " thin provisioning target"); |
| MODULE_AUTHOR("Joe Thornber <dm-devel@redhat.com>"); |
| MODULE_LICENSE("GPL"); |