diff options
Diffstat (limited to 'drivers/md/dm-thin.c')
| -rw-r--r-- | drivers/md/dm-thin.c | 4529 |
1 files changed, 4529 insertions, 0 deletions
diff --git a/drivers/md/dm-thin.c b/drivers/md/dm-thin.c new file mode 100644 index 000000000..601f9e4e6 --- /dev/null +++ b/drivers/md/dm-thin.c @@ -0,0 +1,4529 @@ +/* + * Copyright (C) 2011-2012 Red Hat UK. + * + * This file is released under the GPL. + */ + +#include "dm-thin-metadata.h" +#include "dm-bio-prison-v1.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 int 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 && time_is_before_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 various 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 */ + + /* + * Like READ_ONLY, except may switch back to WRITE on metadata resize. Reported as READ_ONLY. + */ + PM_OUT_OF_METADATA_SPACE, + 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 *data_dev; + 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 work_struct worker; + struct workqueue_struct *wq; + struct throttle throttle; + struct delayed_work waker; + struct delayed_work no_space_timeout; + + unsigned long last_commit_jiffies; + unsigned int ref_count; + + spinlock_t lock; + struct bio_list deferred_flush_bios; + struct bio_list deferred_flush_completions; + 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; + + 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; + + mempool_t mapping_pool; +}; + +static void metadata_operation_failed(struct pool *pool, const char *op, int r); + +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 *descs[] = { + "write", + "out-of-data-space", + "read-only", + "read-only", + "fail" + }; + const char *extra_desc = NULL; + enum pool_mode mode = get_pool_mode(pool); + + if (mode == PM_OUT_OF_DATA_SPACE) { + if (!pool->pf.error_if_no_space) + extra_desc = " (queue IO)"; + else + extra_desc = " (error IO)"; + } + + dm_table_event(pool->ti->table); + DMINFO("%s: switching pool to %s%s mode", + dm_device_name(pool->pool_md), + descs[(int)mode], extra_desc ? : ""); +} + +/* + * 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; + + 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. + */ + refcount_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_NOIO, &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_status) + op->parent_bio->bi_status = errno_to_blk_status(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, blk_status_t error_code) +{ + dm_cell_error(pool->prison, cell, error_code); + dm_bio_prison_free_cell(pool->prison, cell); +} + +static blk_status_t get_pool_io_error_code(struct pool *pool) +{ + return pool->out_of_data_space ? BLK_STS_NOSPC : BLK_STS_IOERR; +} + +static void cell_error(struct pool *pool, struct dm_bio_prison_cell *cell) +{ + cell_error_with_code(pool, cell, get_pool_io_error_code(pool)); +} + +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, BLK_STS_DM_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_exit(void) +{ + mutex_destroy(&dm_thin_pool_table.mutex); +} + +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, blk_status_t error) +{ + struct bio *bio; + + while ((bio = bio_list_pop(bios))) { + bio->bi_status = error; + bio_endio(bio); + } +} + +static void error_thin_bio_list(struct thin_c *tc, struct bio_list *master, + blk_status_t error) +{ + struct bio_list bios; + + bio_list_init(&bios); + + spin_lock_irq(&tc->lock); + __merge_bio_list(&bios, master); + spin_unlock_irq(&tc->lock); + + error_bio_list(&bios, error); +} + +static void requeue_deferred_cells(struct thin_c *tc) +{ + struct pool *pool = tc->pool; + struct list_head cells; + struct dm_bio_prison_cell *cell, *tmp; + + INIT_LIST_HEAD(&cells); + + spin_lock_irq(&tc->lock); + list_splice_init(&tc->deferred_cells, &cells); + spin_unlock_irq(&tc->lock); + + 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; + + bio_list_init(&bios); + + spin_lock_irq(&tc->lock); + __merge_bio_list(&bios, &tc->deferred_bio_list); + __merge_bio_list(&bios, &tc->retry_on_resume_list); + spin_unlock_irq(&tc->lock); + + error_bio_list(&bios, BLK_STS_DM_REQUEUE); + requeue_deferred_cells(tc); +} + +static void error_retry_list_with_code(struct pool *pool, blk_status_t 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) +{ + error_retry_list_with_code(pool, get_pool_io_error_code(pool)); +} + +/* + * 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_set_dev(bio, 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_set_dev(bio, 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; + + if (!bio_triggers_commit(tc, bio)) { + dm_submit_bio_remap(bio, NULL); + 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_irq(&pool->lock); + bio_list_add(&pool->deferred_flush_bios, bio); + spin_unlock_irq(&pool->lock); +} + +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; + + blk_status_t status; + 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->status = read_err || write_err ? BLK_STS_IOERR : 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->status = bio->bi_status; + 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; + int has_work; + + spin_lock_irqsave(&tc->lock, flags); + cell_release_no_holder(pool, cell, &tc->deferred_bio_list); + has_work = !bio_list_empty(&tc->deferred_bio_list); + spin_unlock_irqrestore(&tc->lock, flags); + + if (has_work) + 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 complete_overwrite_bio(struct thin_c *tc, struct bio *bio) +{ + struct pool *pool = tc->pool; + + /* + * If the bio has the REQ_FUA flag set we must commit the metadata + * before signaling its completion. + */ + if (!bio_triggers_commit(tc, bio)) { + bio_endio(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_irq(&pool->lock); + bio_list_add(&pool->deferred_flush_completions, bio); + spin_unlock_irq(&pool->lock); +} + +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->status) { + 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); + complete_overwrite_bio(tc, 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 shared = 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_shared(pool->pmd, b, &shared); + if (r) + goto out; + + if (!shared) + break; + } + + if (b == end) + break; + + /* find end of run */ + for (e = b + 1; e != end; e++) { + r = dm_pool_block_is_shared(pool->pmd, e, &shared); + if (r) + goto out; + + if (shared) + 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); + bio_put(bio); +} + +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; + } + + /* + * 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; + } + + discard_parent = bio_alloc(NULL, 1, 0, GFP_NOIO); + 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); + } +} + +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) +{ + struct list_head maps; + struct dm_thin_new_mapping *m, *tmp; + + INIT_LIST_HEAD(&maps); + spin_lock_irq(&pool->lock); + list_splice_init(head, &maps); + spin_unlock_irq(&pool->lock); + + 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) +{ + struct dm_io_region to; + + to.bdev = tc->pool_dev->bdev; + to.sector = begin; + to.count = end - begin; + + dm_kcopyd_zero(tc->pool->copier, 1, &to, 0, copy_complete, 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) +{ + 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; + + dm_kcopyd_copy(pool->copier, &from, 1, &to, + 0, copy_complete, m); + + /* + * 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 requeue_bios(struct pool *pool); + +static bool is_read_only_pool_mode(enum pool_mode mode) +{ + return (mode == PM_OUT_OF_METADATA_SPACE || mode == PM_READ_ONLY); +} + +static bool is_read_only(struct pool *pool) +{ + return is_read_only_pool_mode(get_pool_mode(pool)); +} + +static void check_for_metadata_space(struct pool *pool) +{ + int r; + const char *ooms_reason = NULL; + dm_block_t nr_free; + + r = dm_pool_get_free_metadata_block_count(pool->pmd, &nr_free); + if (r) + ooms_reason = "Could not get free metadata blocks"; + else if (!nr_free) + ooms_reason = "No free metadata blocks"; + + if (ooms_reason && !is_read_only(pool)) { + DMERR("%s", ooms_reason); + set_pool_mode(pool, PM_OUT_OF_METADATA_SPACE); + } +} + +static void check_for_data_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); + requeue_bios(pool); + } +} + +/* + * 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_OUT_OF_METADATA_SPACE) + return -EINVAL; + + r = dm_pool_commit_metadata(pool->pmd); + if (r) + metadata_operation_failed(pool, "dm_pool_commit_metadata", r); + else { + check_for_metadata_space(pool); + check_for_data_space(pool); + } + + return r; +} + +static void check_low_water_mark(struct pool *pool, dm_block_t free_blocks) +{ + 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_irq(&pool->lock); + pool->low_water_triggered = true; + spin_unlock_irq(&pool->lock); + 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) { + if (r == -ENOSPC) + set_pool_mode(pool, PM_OUT_OF_DATA_SPACE); + else + metadata_operation_failed(pool, "dm_pool_alloc_data_block", r); + return r; + } + + r = dm_pool_get_free_metadata_block_count(pool->pmd, &free_blocks); + if (r) { + metadata_operation_failed(pool, "dm_pool_get_free_metadata_block_count", r); + return r; + } + + if (!free_blocks) { + /* Let's commit before we use up the metadata reserve. */ + r = commit(pool); + if (r) + return r; + } + + return 0; +} + +/* + * If we have run out of space, queue bios until the device is + * resumed, presumably after having been reloaded with more space. + */ +static void retry_on_resume(struct bio *bio) +{ + struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook)); + struct thin_c *tc = h->tc; + + spin_lock_irq(&tc->lock); + bio_list_add(&tc->retry_on_resume_list, bio); + spin_unlock_irq(&tc->lock); +} + +static blk_status_t 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 BLK_STS_IOERR; + + case PM_OUT_OF_DATA_SPACE: + return pool->pf.error_if_no_space ? BLK_STS_NOSPC : 0; + + case PM_OUT_OF_METADATA_SPACE: + case PM_READ_ONLY: + case PM_FAIL: + return BLK_STS_IOERR; + default: + /* Shouldn't get here */ + DMERR_LIMIT("bio unserviceable, yet pool has an unknown mode"); + return BLK_STS_IOERR; + } +} + +static void handle_unserviceable_bio(struct pool *pool, struct bio *bio) +{ + blk_status_t error = should_error_unserviceable_bio(pool); + + if (error) { + bio->bi_status = 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; + blk_status_t 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; + struct bio *bio; + struct bio_list bios; + struct blk_plug plug; + unsigned int count = 0; + + if (tc->requeue_mode) { + error_thin_bio_list(tc, &tc->deferred_bio_list, + BLK_STS_DM_REQUEUE); + return; + } + + bio_list_init(&bios); + + spin_lock_irq(&tc->lock); + + if (bio_list_empty(&tc->deferred_bio_list)) { + spin_unlock_irq(&tc->lock); + return; + } + + __sort_thin_deferred_bios(tc); + + bio_list_merge(&bios, &tc->deferred_bio_list); + bio_list_init(&tc->deferred_bio_list); + + spin_unlock_irq(&tc->lock); + + 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_irq(&tc->lock); + bio_list_add(&tc->deferred_bio_list, bio); + bio_list_merge(&tc->deferred_bio_list, &bios); + spin_unlock_irq(&tc->lock); + 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); + } + cond_resched(); + } + 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 int sort_cells(struct pool *pool, struct list_head *cells) +{ + unsigned int 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; + struct list_head cells; + struct dm_bio_prison_cell *cell; + unsigned int i, j, count; + + INIT_LIST_HEAD(&cells); + + spin_lock_irq(&tc->lock); + list_splice_init(&tc->deferred_cells, &cells); + spin_unlock_irq(&tc->lock); + + 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_irq(&tc->lock); + list_splice(&cells, &tc->deferred_cells); + spin_unlock_irq(&tc->lock); + return; + } + + if (bio_op(cell->holder) == REQ_OP_DISCARD) + pool->process_discard_cell(tc, cell); + else + pool->process_cell(tc, cell); + } + cond_resched(); + } 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) +{ + struct bio *bio; + struct bio_list bios, bio_completions; + 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 or signaling their completion. + */ + bio_list_init(&bios); + bio_list_init(&bio_completions); + + spin_lock_irq(&pool->lock); + bio_list_merge(&bios, &pool->deferred_flush_bios); + bio_list_init(&pool->deferred_flush_bios); + + bio_list_merge(&bio_completions, &pool->deferred_flush_completions); + bio_list_init(&pool->deferred_flush_completions); + spin_unlock_irq(&pool->lock); + + if (bio_list_empty(&bios) && bio_list_empty(&bio_completions) && + !(dm_pool_changed_this_transaction(pool->pmd) && need_commit_due_to_time(pool))) + return; + + if (commit(pool)) { + bio_list_merge(&bios, &bio_completions); + + while ((bio = bio_list_pop(&bios))) + bio_io_error(bio); + return; + } + pool->last_commit_jiffies = jiffies; + + while ((bio = bio_list_pop(&bio_completions))) + bio_endio(bio); + + while ((bio = bio_list_pop(&bios))) { + /* + * The data device was flushed as part of metadata commit, + * so complete redundant flushes immediately. + */ + if (bio->bi_opf & REQ_PREFLUSH) + bio_endio(bio); + else + dm_submit_bio_remap(bio, NULL); + } +} + +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); +} + +/* + * 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(pool); + error_retry_list_with_code(pool, BLK_STS_NOSPC); + } +} + +/*----------------------------------------------------------------*/ + +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 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 = READ_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: + 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_OUT_OF_METADATA_SPACE: + case PM_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. + */ + 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 == PM_OUT_OF_DATA_SPACE) + cancel_delayed_work_sync(&pool->no_space_timeout); + 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; + + if (old_mode != new_mode) + notify_of_pool_mode_change(pool); +} + +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) +{ + struct pool *pool = tc->pool; + + spin_lock_irq(&tc->lock); + bio_list_add(&tc->deferred_bio_list, bio); + spin_unlock_irq(&tc->lock); + + 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) +{ + struct pool *pool = tc->pool; + + throttle_lock(&pool->throttle); + spin_lock_irq(&tc->lock); + list_add_tail(&cell->user_list, &tc->deferred_cells); + spin_unlock_irq(&tc->lock); + 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_status = BLK_STS_DM_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 void requeue_bios(struct pool *pool) +{ + struct thin_c *tc; + + rcu_read_lock(); + list_for_each_entry_rcu(tc, &pool->active_thins, list) { + spin_lock_irq(&tc->lock); + bio_list_merge(&tc->deferred_bio_list, &tc->retry_on_resume_list); + bio_list_init(&tc->retry_on_resume_list); + spin_unlock_irq(&tc->lock); + } + rcu_read_unlock(); +} + +/*---------------------------------------------------------------- + * Binding of control targets to a pool object + *--------------------------------------------------------------*/ +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; + + if (!pt->adjusted_pf.discard_passdown) + return; + + if (!bdev_max_discard_sectors(pt->data_dev->bdev)) + 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 (%pg) %s: Disabling discard passdown.", data_bdev, 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); + + cancel_delayed_work_sync(&pool->waker); + cancel_delayed_work_sync(&pool->no_space_timeout); + if (pool->wq) + destroy_workqueue(pool->wq); + + if (pool->next_mapping) + mempool_free(pool->next_mapping, &pool->mapping_pool); + mempool_exit(&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, + struct block_device *data_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 = kzalloc(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); + bio_list_init(&pool->deferred_flush_completions); + 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; + r = mempool_init_slab_pool(&pool->mapping_pool, MAPPING_POOL_SIZE, + _new_mapping_cache); + if (r) { + *error = "Error creating pool's mapping mempool"; + err_p = ERR_PTR(r); + goto bad_mapping_pool; + } + + pool->cell_sort_array = + vmalloc(array_size(CELL_SORT_ARRAY_SIZE, + sizeof(*pool->cell_sort_array))); + 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->data_dev = data_dev; + __pool_table_insert(pool); + + return pool; + +bad_sort_array: + mempool_exit(&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, + struct block_device *data_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); + } + if (pool->data_dev != data_dev) { + *error = "data 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 || pool->data_dev != data_dev) { + *error = "different pool cannot replace a pool"; + return ERR_PTR(-EINVAL); + } + __pool_inc(pool); + + } else { + pool = pool_create(pool_md, metadata_dev, data_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 int argc; + const char *arg_name; + + static const 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); +} + +/* + * We need to flush the data device **before** committing the metadata. + * + * This ensures that the data blocks of any newly inserted mappings are + * properly written to non-volatile storage and won't be lost in case of a + * crash. + * + * Failure to do so can result in data corruption in the case of internal or + * external snapshots and in the case of newly provisioned blocks, when block + * zeroing is enabled. + */ +static int metadata_pre_commit_callback(void *context) +{ + struct pool *pool = context; + + return blkdev_issue_flush(pool->data_dev); +} + +static sector_t get_dev_size(struct block_device *bdev) +{ + return bdev_nr_sectors(bdev); +} + +static void warn_if_metadata_device_too_big(struct block_device *bdev) +{ + sector_t metadata_dev_size = get_dev_size(bdev); + + if (metadata_dev_size > THIN_METADATA_MAX_SECTORS_WARNING) + DMWARN("Metadata device %pg is larger than %u sectors: excess space will not be used.", + bdev, 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 int 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; + + /* make sure metadata and data are different devices */ + if (!strcmp(argv[0], argv[1])) { + ti->error = "Error setting metadata or data device"; + r = -EINVAL; + goto out_unlock; + } + + /* + * 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, data_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; + ti->limit_swap_bios = true; + + /* + * Only need to enable discards if the pool should pass + * them down to the data device. The thin device's discard + * processing will cause mappings to be removed from the btree. + */ + if (pf.discard_enabled && pf.discard_passdown) { + ti->num_discard_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) { + ti->error = "Error registering metadata threshold"; + goto out_flags_changed; + } + + dm_pool_register_pre_commit_callback(pool->pmd, + metadata_pre_commit_callback, pool); + + 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; + + /* + * As this is a singleton target, ti->begin is always zero. + */ + spin_lock_irq(&pool->lock); + bio_set_dev(bio, pt->data_dev->bdev); + r = DM_MAPIO_REMAPPED; + spin_unlock_irq(&pool->lock); + + 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); + + if (get_pool_mode(pool) == PM_OUT_OF_METADATA_SPACE) + set_pool_mode(pool, PM_WRITE); + + 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) + goto out; + + r = maybe_resize_data_dev(ti, &need_commit1); + if (r) + goto out; + + r = maybe_resize_metadata_dev(ti, &need_commit2); + if (r) + goto out; + + if (need_commit1 || need_commit2) + (void) commit(pool); +out: + /* + * When a thin-pool is PM_FAIL, it cannot be rebuilt if + * bio is in deferred list. Therefore need to return 0 + * to allow pool_resume() to flush IO. + */ + if (r && get_pool_mode(pool) == PM_FAIL) + r = 0; + + return r; +} + +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; + + /* + * Must requeue active_thins' bios and then resume + * active_thins _before_ clearing 'suspend' flag. + */ + requeue_bios(pool); + pool_resume_active_thins(pool); + + spin_lock_irq(&pool->lock); + pool->low_water_triggered = false; + pool->suspended = false; + spin_unlock_irq(&pool->lock); + + do_waker(&pool->waker.work); +} + +static void pool_presuspend(struct dm_target *ti) +{ + struct pool_c *pt = ti->private; + struct pool *pool = pt->pool; + + spin_lock_irq(&pool->lock); + pool->suspended = true; + spin_unlock_irq(&pool->lock); + + 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; + + pool_resume_active_thins(pool); + + spin_lock_irq(&pool->lock); + pool->suspended = false; + spin_unlock_irq(&pool->lock); +} + +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 int argc, unsigned int 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 int 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 int 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 int 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 int 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 int 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 int 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 int argc, char **argv, + char *result, unsigned int maxlen) +{ + int r = -EINVAL; + struct pool_c *pt = ti->private; + struct pool *pool = pt->pool; + + if (get_pool_mode(pool) >= PM_OUT_OF_METADATA_SPACE) { + 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 int sz, unsigned int maxlen) +{ + unsigned int 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 int status_flags, char *result, unsigned int maxlen) +{ + int r; + unsigned int 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; + enum pool_mode mode; + 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("- "); + + mode = get_pool_mode(pool); + if (mode == PM_OUT_OF_DATA_SPACE) + DMEMIT("out_of_data_space "); + else if (is_read_only_pool_mode(mode)) + 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("- "); + + DMEMIT("%llu ", (unsigned long long)calc_metadata_threshold(pt)); + + 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; + + case STATUSTYPE_IMA: + *result = '\0'; + 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. + */ + 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, 22, 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) +{ + refcount_inc(&tc->refcount); +} + +static void thin_put(struct thin_c *tc) +{ + if (refcount_dec_and_test(&tc->refcount)) + complete(&tc->can_destroy); +} + +static void thin_dtr(struct dm_target *ti) +{ + struct thin_c *tc = ti->private; + + spin_lock_irq(&tc->pool->lock); + list_del_rcu(&tc->list); + spin_unlock_irq(&tc->pool->lock); + 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 int argc, char **argv) +{ + int r; + struct thin_c *tc; + struct dm_dev *pool_dev, *origin_dev; + struct mapped_device *pool_md; + + mutex_lock(&dm_thin_pool_table.mutex); + + if (argc != 2 && argc != 3) { + ti->error = "Invalid argument count"; + r = -EINVAL; + goto out_unlock; + } + + tc = ti->private = kzalloc(sizeof(*tc), GFP_KERNEL); + if (!tc) { + ti->error = "Out of memory"; + r = -ENOMEM; + goto out_unlock; + } + 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) { + if (!strcmp(argv[0], argv[2])) { + ti->error = "Error setting origin device"; + r = -EINVAL; + goto bad_origin_dev; + } + + 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->limit_swap_bios = true; + ti->flush_supported = true; + ti->accounts_remapped_io = true; + ti->per_io_data_size = sizeof(struct dm_thin_endio_hook); + + /* In case the pool supports discards, pass them on. */ + if (tc->pool->pf.discard_enabled) { + ti->discards_supported = true; + ti->num_discard_bios = 1; + } + + mutex_unlock(&dm_thin_pool_table.mutex); + + spin_lock_irq(&tc->pool->lock); + if (tc->pool->suspended) { + spin_unlock_irq(&tc->pool->lock); + 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; + } + refcount_set(&tc->refcount, 1); + init_completion(&tc->can_destroy); + list_add_tail_rcu(&tc->list, &tc->pool->active_thins); + spin_unlock_irq(&tc->pool->lock); + /* + * This synchronize_rcu() call is needed here otherwise we risk a + * wake_worker() call finding no bios to process (because the newly + * added tc isn't yet visible). So this reduces latency since we + * aren't then dependent on the periodic commit to wake_worker(). + */ + synchronize_rcu(); + + 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, + blk_status_t *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 DM_ENDIO_DONE; +} + +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 int status_flags, char *result, unsigned int 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; + + case STATUSTYPE_IMA: + *result = '\0'; + 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, 22, 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 = -ENOMEM; + + pool_table_init(); + + _new_mapping_cache = KMEM_CACHE(dm_thin_new_mapping, 0); + if (!_new_mapping_cache) + return r; + + r = dm_register_target(&thin_target); + if (r) + goto bad_new_mapping_cache; + + r = dm_register_target(&pool_target); + if (r) + goto bad_thin_target; + + return 0; + +bad_thin_target: + dm_unregister_target(&thin_target); +bad_new_mapping_cache: + kmem_cache_destroy(_new_mapping_cache); + + return r; +} + +static void dm_thin_exit(void) +{ + dm_unregister_target(&thin_target); + dm_unregister_target(&pool_target); + + kmem_cache_destroy(_new_mapping_cache); + + pool_table_exit(); +} + +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"); |