| Author | Tokens | Token Proportion | Commits | Commit Proportion |
|---|---|---|---|---|
| Joe Thornber | 15533 | 80.32% | 63 | 36.63% |
| Mike Snitzer | 3007 | 15.55% | 69 | 40.12% |
| Mikulas Patocka | 243 | 1.26% | 7 | 4.07% |
| Nikos Tsironis | 172 | 0.89% | 1 | 0.58% |
| Christoph Hellwig | 89 | 0.46% | 5 | 2.91% |
| Vallish Vaidyeshwara | 57 | 0.29% | 1 | 0.58% |
| Michael Christie | 50 | 0.26% | 3 | 1.74% |
| Alasdair G. Kergon | 49 | 0.25% | 7 | 4.07% |
| Kent Overstreet | 42 | 0.22% | 3 | 1.74% |
| monty_pavel@sina.com | 22 | 0.11% | 1 | 0.58% |
| Marc Dionne | 17 | 0.09% | 1 | 0.58% |
| Andy Grover | 15 | 0.08% | 1 | 0.58% |
| Hou Tao | 11 | 0.06% | 1 | 0.58% |
| Manuel Schölling | 9 | 0.05% | 1 | 0.58% |
| Dennis Yang | 5 | 0.03% | 1 | 0.58% |
| Kees Cook | 5 | 0.03% | 1 | 0.58% |
| John Pittman | 4 | 0.02% | 1 | 0.58% |
| Jens Axboe | 4 | 0.02% | 1 | 0.58% |
| Nikolay Borisov | 2 | 0.01% | 1 | 0.58% |
| Amitoj Kaur Chawla | 1 | 0.01% | 1 | 0.58% |
| Eric Biggers | 1 | 0.01% | 1 | 0.58% |
| Mark Rutland | 1 | 0.01% | 1 | 0.58% |
| Total | 19339 | 172 |
/* * 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 no_space_timeout_secs = NO_SPACE_TIMEOUT_SECS; DECLARE_DM_KCOPYD_THROTTLE_WITH_MODULE_PARM(snapshot_copy_throttle, "A percentage of time allocated for copy on write"); /* * The block size of the device holding pool data must be * between 64KB and 1GB. */ #define DATA_DEV_BLOCK_SIZE_MIN_SECTORS (64 * 1024 >> SECTOR_SHIFT) #define DATA_DEV_BLOCK_SIZE_MAX_SECTORS (1024 * 1024 * 1024 >> SECTOR_SHIFT) /* * Device id is restricted to 24 bits. */ #define MAX_DEV_ID ((1 << 24) - 1) /* * How do we handle breaking sharing of data blocks? * ================================================= * * We use a standard copy-on-write btree to store the mappings for the * devices (note I'm talking about copy-on-write of the metadata here, not * the data). When you take an internal snapshot you clone the root node * of the origin btree. After this there is no concept of an origin or a * snapshot. They are just two device trees that happen to point to the * same data blocks. * * When we get a write in we decide if it's to a shared data block using * some timestamp magic. If it is, we have to break sharing. * * Let's say we write to a shared block in what was the origin. The * steps are: * * i) plug io further to this physical block. (see bio_prison code). * * ii) quiesce any read io to that shared data block. Obviously * including all devices that share this block. (see dm_deferred_set code) * * iii) copy the data block to a newly allocate block. This step can be * missed out if the io covers the block. (schedule_copy). * * iv) insert the new mapping into the origin's btree * (process_prepared_mapping). This act of inserting breaks some * sharing of btree nodes between the two devices. Breaking sharing only * effects the btree of that specific device. Btrees for the other * devices that share the block never change. The btree for the origin * device as it was after the last commit is untouched, ie. we're using * persistent data structures in the functional programming sense. * * v) unplug io to this physical block, including the io that triggered * the breaking of sharing. * * Steps (ii) and (iii) occur in parallel. * * The metadata _doesn't_ need to be committed before the io continues. We * get away with this because the io is always written to a _new_ block. * If there's a crash, then: * * - The origin mapping will point to the old origin block (the shared * one). This will contain the data as it was before the io that triggered * the breaking of sharing came in. * * - The snap mapping still points to the old block. As it would after * the commit. * * The downside of this scheme is the timestamp magic isn't perfect, and * will continue to think that data block in the snapshot device is shared * even after the write to the origin has broken sharing. I suspect data * blocks will typically be shared by many different devices, so we're * breaking sharing n + 1 times, rather than n, where n is the number of * devices that reference this data block. At the moment I think the * benefits far, far outweigh the disadvantages. */ /*----------------------------------------------------------------*/ /* * Key building. */ enum lock_space { VIRTUAL, PHYSICAL }; static void build_key(struct dm_thin_device *td, enum lock_space ls, dm_block_t b, dm_block_t e, struct dm_cell_key *key) { key->virtual = (ls == VIRTUAL); key->dev = dm_thin_dev_id(td); key->block_begin = b; key->block_end = e; } static void build_data_key(struct dm_thin_device *td, dm_block_t b, struct dm_cell_key *key) { build_key(td, PHYSICAL, b, b + 1llu, key); } static void build_virtual_key(struct dm_thin_device *td, dm_block_t b, struct dm_cell_key *key) { build_key(td, VIRTUAL, b, b + 1llu, key); } /*----------------------------------------------------------------*/ #define THROTTLE_THRESHOLD (1 * HZ) struct throttle { struct rw_semaphore lock; unsigned long threshold; bool throttle_applied; }; static void throttle_init(struct throttle *t) { init_rwsem(&t->lock); t->throttle_applied = false; } static void throttle_work_start(struct throttle *t) { t->threshold = jiffies + THROTTLE_THRESHOLD; } static void throttle_work_update(struct throttle *t) { if (!t->throttle_applied && jiffies > t->threshold) { down_write(&t->lock); t->throttle_applied = true; } } static void throttle_work_complete(struct throttle *t) { if (t->throttle_applied) { t->throttle_applied = false; up_write(&t->lock); } } static void throttle_lock(struct throttle *t) { down_read(&t->lock); } static void throttle_unlock(struct throttle *t) { up_read(&t->lock); } /*----------------------------------------------------------------*/ /* * A pool device ties together a metadata device and a data device. It * also provides the interface for creating and destroying internal * devices. */ struct dm_thin_new_mapping; /* * The pool runs in 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 *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 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; struct dm_target_callbacks callbacks; dm_block_t low_water_blocks; struct pool_features requested_pf; /* Features requested during table load */ struct pool_features adjusted_pf; /* Features used after adjusting for constituent devices */ }; /* * Target context for a thin. */ struct thin_c { struct list_head list; struct dm_dev *pool_dev; struct dm_dev *origin_dev; sector_t origin_size; dm_thin_id dev_id; struct pool *pool; struct dm_thin_device *td; struct mapped_device *thin_md; bool requeue_mode:1; spinlock_t lock; struct list_head deferred_cells; struct bio_list deferred_bio_list; struct bio_list retry_on_resume_list; struct rb_root sort_bio_list; /* sorted list of deferred bios */ /* * Ensures the thin is not destroyed until the worker has finished * iterating the active_thins list. */ 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_NOWAIT, 0, &op->bio); } static void end_discard(struct discard_op *op, int r) { if (op->bio) { /* * Even if one of the calls to issue_discard failed, we * need to wait for the chain to complete. */ bio_chain(op->bio, op->parent_bio); bio_set_op_attrs(op->bio, REQ_OP_DISCARD, 0); submit_bio(op->bio); } blk_finish_plug(&op->plug); /* * Even if r is set, there could be sub discards in flight that we * need to wait for. */ if (r && !op->parent_bio->bi_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; unsigned long flags; bio_list_init(&bios); spin_lock_irqsave(&tc->lock, flags); __merge_bio_list(&bios, master); spin_unlock_irqrestore(&tc->lock, flags); error_bio_list(&bios, error); } static void requeue_deferred_cells(struct thin_c *tc) { struct pool *pool = tc->pool; unsigned long flags; struct list_head cells; struct dm_bio_prison_cell *cell, *tmp; INIT_LIST_HEAD(&cells); spin_lock_irqsave(&tc->lock, flags); list_splice_init(&tc->deferred_cells, &cells); spin_unlock_irqrestore(&tc->lock, flags); list_for_each_entry_safe(cell, tmp, &cells, user_list) cell_requeue(pool, cell); } static void requeue_io(struct thin_c *tc) { struct bio_list bios; unsigned long flags; bio_list_init(&bios); spin_lock_irqsave(&tc->lock, flags); __merge_bio_list(&bios, &tc->deferred_bio_list); __merge_bio_list(&bios, &tc->retry_on_resume_list); spin_unlock_irqrestore(&tc->lock, flags); error_bio_list(&bios, 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; unsigned long flags; if (!bio_triggers_commit(tc, bio)) { generic_make_request(bio); return; } /* * Complete bio with an error if earlier I/O caused changes to * the metadata that can't be committed e.g, due to I/O errors * on the metadata device. */ if (dm_thin_aborted_changes(tc->td)) { bio_io_error(bio); return; } /* * Batch together any bios that trigger commits and then issue a * single commit for them in process_deferred_bios(). */ spin_lock_irqsave(&pool->lock, flags); bio_list_add(&pool->deferred_flush_bios, bio); spin_unlock_irqrestore(&pool->lock, flags); } static void remap_to_origin_and_issue(struct thin_c *tc, struct bio *bio) { remap_to_origin(tc, bio); issue(tc, bio); } static void remap_and_issue(struct thin_c *tc, struct bio *bio, dm_block_t block) { remap(tc, bio, block); issue(tc, bio); } /*----------------------------------------------------------------*/ /* * Bio endio functions. */ struct dm_thin_new_mapping { struct list_head list; bool pass_discard:1; bool maybe_shared:1; /* * Track quiescing, copying and zeroing preparation actions. When this * counter hits zero the block is prepared and can be inserted into the * btree. */ atomic_t prepare_actions; 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; spin_lock_irqsave(&tc->lock, flags); cell_release_no_holder(pool, cell, &tc->deferred_bio_list); spin_unlock_irqrestore(&tc->lock, flags); wake_worker(pool); } static void thin_defer_bio(struct thin_c *tc, struct bio *bio); struct remap_info { struct thin_c *tc; struct bio_list defer_bios; struct bio_list issue_bios; }; static void __inc_remap_and_issue_cell(void *context, struct dm_bio_prison_cell *cell) { struct remap_info *info = context; struct bio *bio; while ((bio = bio_list_pop(&cell->bios))) { if (op_is_flush(bio->bi_opf) || bio_op(bio) == REQ_OP_DISCARD) bio_list_add(&info->defer_bios, bio); else { inc_all_io_entry(info->tc->pool, bio); /* * We can't issue the bios with the bio prison lock * held, so we add them to a list to issue on * return from this function. */ bio_list_add(&info->issue_bios, bio); } } } static void inc_remap_and_issue_cell(struct thin_c *tc, struct dm_bio_prison_cell *cell, dm_block_t block) { struct bio *bio; struct remap_info info; info.tc = tc; bio_list_init(&info.defer_bios); bio_list_init(&info.issue_bios); /* * We have to be careful to inc any bios we're about to issue * before the cell is released, and avoid a race with new bios * being added to the cell. */ cell_visit_release(tc->pool, __inc_remap_and_issue_cell, &info, cell); while ((bio = bio_list_pop(&info.defer_bios))) thin_defer_bio(tc, bio); while ((bio = bio_list_pop(&info.issue_bios))) remap_and_issue(info.tc, bio, block); } static void process_prepared_mapping_fail(struct dm_thin_new_mapping *m) { cell_error(m->tc->pool, m->cell); list_del(&m->list); mempool_free(m, &m->tc->pool->mapping_pool); } static void complete_overwrite_bio(struct thin_c *tc, struct bio *bio) { struct pool *pool = tc->pool; unsigned long flags; /* * 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_irqsave(&pool->lock, flags); bio_list_add(&pool->deferred_flush_completions, bio); spin_unlock_irqrestore(&pool->lock, flags); } 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(GFP_NOIO, 1); if (!discard_parent) { DMWARN("%s: unable to allocate top level discard bio for passdown. Skipping passdown.", dm_device_name(tc->pool->pool_md)); queue_passdown_pt2(m); } else { discard_parent->bi_end_io = passdown_endio; discard_parent->bi_private = m; if (m->maybe_shared) passdown_double_checking_shared_status(m, discard_parent); else { struct discard_op op; begin_discard(&op, tc, discard_parent); r = issue_discard(&op, m->data_block, data_end); end_discard(&op, r); } } } static void process_prepared_discard_passdown_pt2(struct dm_thin_new_mapping *m) { int r; struct thin_c *tc = m->tc; struct pool *pool = tc->pool; /* * The passdown has completed, so now we can decrement all those * unmapped blocks. */ r = dm_pool_dec_data_range(pool->pmd, m->data_block, m->data_block + (m->virt_end - m->virt_begin)); if (r) { metadata_operation_failed(pool, "dm_pool_dec_data_range", r); bio_io_error(m->bio); } else bio_endio(m->bio); cell_defer_no_holder(tc, m->cell); mempool_free(m, &pool->mapping_pool); } static void process_prepared(struct pool *pool, struct list_head *head, process_mapping_fn *fn) { unsigned long flags; struct list_head maps; struct dm_thin_new_mapping *m, *tmp; INIT_LIST_HEAD(&maps); spin_lock_irqsave(&pool->lock, flags); list_splice_init(head, &maps); spin_unlock_irqrestore(&pool->lock, flags); list_for_each_entry_safe(m, tmp, &maps, list) (*fn)(m); } /* * Deferred bio jobs. */ static int io_overlaps_block(struct pool *pool, struct bio *bio) { return bio->bi_iter.bi_size == (pool->sectors_per_block << SECTOR_SHIFT); } static int io_overwrites_block(struct pool *pool, struct bio *bio) { return (bio_data_dir(bio) == WRITE) && io_overlaps_block(pool, bio); } static void save_and_set_endio(struct bio *bio, bio_end_io_t **save, bio_end_io_t *fn) { *save = bio->bi_end_io; bio->bi_end_io = fn; } static int ensure_next_mapping(struct pool *pool) { if (pool->next_mapping) return 0; pool->next_mapping = mempool_alloc(&pool->mapping_pool, GFP_ATOMIC); return pool->next_mapping ? 0 : -ENOMEM; } static struct dm_thin_new_mapping *get_next_mapping(struct pool *pool) { struct dm_thin_new_mapping *m = pool->next_mapping; BUG_ON(!pool->next_mapping); memset(m, 0, sizeof(struct dm_thin_new_mapping)); INIT_LIST_HEAD(&m->list); m->bio = NULL; pool->next_mapping = NULL; return m; } static void ll_zero(struct thin_c *tc, struct dm_thin_new_mapping *m, sector_t begin, sector_t end) { 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) { unsigned long flags; if (free_blocks <= pool->low_water_blocks && !pool->low_water_triggered) { DMWARN("%s: reached low water mark for data device: sending event.", dm_device_name(pool->pool_md)); spin_lock_irqsave(&pool->lock, flags); pool->low_water_triggered = true; spin_unlock_irqrestore(&pool->lock, flags); dm_table_event(pool->ti->table); } } static int alloc_data_block(struct thin_c *tc, dm_block_t *result) { int r; dm_block_t free_blocks; struct pool *pool = tc->pool; if (WARN_ON(get_pool_mode(pool) != PM_WRITE)) return -EINVAL; r = dm_pool_get_free_block_count(pool->pmd, &free_blocks); if (r) { metadata_operation_failed(pool, "dm_pool_get_free_block_count", r); return r; } check_low_water_mark(pool, free_blocks); if (!free_blocks) { /* * Try to commit to see if that will free up some * more space. */ r = commit(pool); if (r) return r; r = dm_pool_get_free_block_count(pool->pmd, &free_blocks); if (r) { metadata_operation_failed(pool, "dm_pool_get_free_block_count", r); return r; } if (!free_blocks) { set_pool_mode(pool, PM_OUT_OF_DATA_SPACE); return -ENOSPC; } } r = dm_pool_alloc_data_block(pool->pmd, result); if (r) { 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; unsigned long flags; spin_lock_irqsave(&tc->lock, flags); bio_list_add(&tc->retry_on_resume_list, bio); spin_unlock_irqrestore(&tc->lock, flags); } static 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; unsigned long flags; struct bio *bio; struct bio_list bios; struct blk_plug plug; unsigned count = 0; if (tc->requeue_mode) { error_thin_bio_list(tc, &tc->deferred_bio_list, BLK_STS_DM_REQUEUE); return; } bio_list_init(&bios); spin_lock_irqsave(&tc->lock, flags); if (bio_list_empty(&tc->deferred_bio_list)) { spin_unlock_irqrestore(&tc->lock, flags); return; } __sort_thin_deferred_bios(tc); bio_list_merge(&bios, &tc->deferred_bio_list); bio_list_init(&tc->deferred_bio_list); spin_unlock_irqrestore(&tc->lock, flags); blk_start_plug(&plug); while ((bio = bio_list_pop(&bios))) { /* * If we've got no free new_mapping structs, and processing * this bio might require one, we pause until there are some * prepared mappings to process. */ if (ensure_next_mapping(pool)) { spin_lock_irqsave(&tc->lock, flags); bio_list_add(&tc->deferred_bio_list, bio); bio_list_merge(&tc->deferred_bio_list, &bios); spin_unlock_irqrestore(&tc->lock, flags); break; } if (bio_op(bio) == REQ_OP_DISCARD) pool->process_discard(tc, bio); else pool->process_bio(tc, bio); if ((count++ & 127) == 0) { throttle_work_update(&pool->throttle); dm_pool_issue_prefetches(pool->pmd); } } blk_finish_plug(&plug); } static int cmp_cells(const void *lhs, const void *rhs) { struct dm_bio_prison_cell *lhs_cell = *((struct dm_bio_prison_cell **) lhs); struct dm_bio_prison_cell *rhs_cell = *((struct dm_bio_prison_cell **) rhs); BUG_ON(!lhs_cell->holder); BUG_ON(!rhs_cell->holder); if (lhs_cell->holder->bi_iter.bi_sector < rhs_cell->holder->bi_iter.bi_sector) return -1; if (lhs_cell->holder->bi_iter.bi_sector > rhs_cell->holder->bi_iter.bi_sector) return 1; return 0; } static unsigned sort_cells(struct pool *pool, struct list_head *cells) { unsigned count = 0; struct dm_bio_prison_cell *cell, *tmp; list_for_each_entry_safe(cell, tmp, cells, user_list) { if (count >= CELL_SORT_ARRAY_SIZE) break; pool->cell_sort_array[count++] = cell; list_del(&cell->user_list); } sort(pool->cell_sort_array, count, sizeof(cell), cmp_cells, NULL); return count; } static void process_thin_deferred_cells(struct thin_c *tc) { struct pool *pool = tc->pool; unsigned long flags; struct list_head cells; struct dm_bio_prison_cell *cell; unsigned i, j, count; INIT_LIST_HEAD(&cells); spin_lock_irqsave(&tc->lock, flags); list_splice_init(&tc->deferred_cells, &cells); spin_unlock_irqrestore(&tc->lock, flags); if (list_empty(&cells)) return; do { count = sort_cells(tc->pool, &cells); for (i = 0; i < count; i++) { cell = pool->cell_sort_array[i]; BUG_ON(!cell->holder); /* * If we've got no free new_mapping structs, and processing * this bio might require one, we pause until there are some * prepared mappings to process. */ if (ensure_next_mapping(pool)) { for (j = i; j < count; j++) list_add(&pool->cell_sort_array[j]->user_list, &cells); spin_lock_irqsave(&tc->lock, flags); list_splice(&cells, &tc->deferred_cells); spin_unlock_irqrestore(&tc->lock, flags); return; } if (bio_op(cell->holder) == REQ_OP_DISCARD) pool->process_discard_cell(tc, cell); else pool->process_cell(tc, cell); } } while (!list_empty(&cells)); } static void thin_get(struct thin_c *tc); static void thin_put(struct thin_c *tc); /* * We can't hold rcu_read_lock() around code that can block. So we * find a thin with the rcu lock held; bump a refcount; then drop * the lock. */ static struct thin_c *get_first_thin(struct pool *pool) { struct thin_c *tc = NULL; rcu_read_lock(); if (!list_empty(&pool->active_thins)) { tc = list_entry_rcu(pool->active_thins.next, struct thin_c, list); thin_get(tc); } rcu_read_unlock(); return tc; } static struct thin_c *get_next_thin(struct pool *pool, struct thin_c *tc) { struct thin_c *old_tc = tc; rcu_read_lock(); list_for_each_entry_continue_rcu(tc, &pool->active_thins, list) { thin_get(tc); thin_put(old_tc); rcu_read_unlock(); return tc; } thin_put(old_tc); rcu_read_unlock(); return NULL; } static void process_deferred_bios(struct pool *pool) { unsigned long flags; struct bio *bio; struct bio_list bios, 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_irqsave(&pool->lock, flags); 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_irqrestore(&pool->lock, flags); 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))) generic_make_request(bio); } static void do_worker(struct work_struct *ws) { struct pool *pool = container_of(ws, struct pool, worker); throttle_work_start(&pool->throttle); dm_pool_issue_prefetches(pool->pmd); throttle_work_update(&pool->throttle); process_prepared(pool, &pool->prepared_mappings, &pool->process_prepared_mapping); throttle_work_update(&pool->throttle); process_prepared(pool, &pool->prepared_discards, &pool->process_prepared_discard); throttle_work_update(&pool->throttle); process_prepared(pool, &pool->prepared_discards_pt2, &pool->process_prepared_discard_pt2); throttle_work_update(&pool->throttle); process_deferred_bios(pool); throttle_work_complete(&pool->throttle); } /* * We want to commit periodically so that not too much * unwritten data builds up. */ static void do_waker(struct work_struct *ws) { struct pool *pool = container_of(to_delayed_work(ws), struct pool, waker); wake_worker(pool); queue_delayed_work(pool->wq, &pool->waker, COMMIT_PERIOD); } /* * 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) { unsigned long flags; struct pool *pool = tc->pool; spin_lock_irqsave(&tc->lock, flags); bio_list_add(&tc->deferred_bio_list, bio); spin_unlock_irqrestore(&tc->lock, flags); wake_worker(pool); } static void thin_defer_bio_with_throttle(struct thin_c *tc, struct bio *bio) { struct pool *pool = tc->pool; throttle_lock(&pool->throttle); thin_defer_bio(tc, bio); throttle_unlock(&pool->throttle); } static void thin_defer_cell(struct thin_c *tc, struct dm_bio_prison_cell *cell) { unsigned long flags; struct pool *pool = tc->pool; throttle_lock(&pool->throttle); spin_lock_irqsave(&tc->lock, flags); list_add_tail(&cell->user_list, &tc->deferred_cells); spin_unlock_irqrestore(&tc->lock, flags); throttle_unlock(&pool->throttle); wake_worker(pool); } static void thin_hook_bio(struct thin_c *tc, struct bio *bio) { struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook)); h->tc = tc; h->shared_read_entry = NULL; h->all_io_entry = NULL; h->overwrite_mapping = NULL; h->cell = NULL; } /* * Non-blocking function called from the thin target's map function. */ static int thin_bio_map(struct dm_target *ti, struct bio *bio) { int r; struct thin_c *tc = ti->private; dm_block_t block = get_bio_block(tc, bio); struct dm_thin_device *td = tc->td; struct dm_thin_lookup_result result; struct dm_bio_prison_cell *virt_cell, *data_cell; struct dm_cell_key key; thin_hook_bio(tc, bio); if (tc->requeue_mode) { bio->bi_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 int pool_is_congested(struct dm_target_callbacks *cb, int bdi_bits) { struct pool_c *pt = container_of(cb, struct pool_c, callbacks); struct request_queue *q; if (get_pool_mode(pt->pool) == PM_OUT_OF_DATA_SPACE) return 1; q = bdev_get_queue(pt->data_dev->bdev); return bdi_congested(q->backing_dev_info, bdi_bits); } static void requeue_bios(struct pool *pool) { unsigned long flags; struct thin_c *tc; rcu_read_lock(); list_for_each_entry_rcu(tc, &pool->active_thins, list) { spin_lock_irqsave(&tc->lock, flags); bio_list_merge(&tc->deferred_bio_list, &tc->retry_on_resume_list); bio_list_init(&tc->retry_on_resume_list); spin_unlock_irqrestore(&tc->lock, flags); } rcu_read_unlock(); } /*---------------------------------------------------------------- * Binding of control targets to a pool object *--------------------------------------------------------------*/ static bool data_dev_supports_discard(struct pool_c *pt) { struct request_queue *q = bdev_get_queue(pt->data_dev->bdev); return q && blk_queue_discard(q); } static bool is_factor(sector_t block_size, uint32_t n) { return !sector_div(block_size, n); } /* * If discard_passdown was enabled verify that the data device * supports discards. Disable discard_passdown if not. */ static void disable_passdown_if_not_supported(struct pool_c *pt) { struct pool *pool = pt->pool; struct block_device *data_bdev = pt->data_dev->bdev; struct queue_limits *data_limits = &bdev_get_queue(data_bdev)->limits; const char *reason = NULL; char buf[BDEVNAME_SIZE]; if (!pt->adjusted_pf.discard_passdown) return; if (!data_dev_supports_discard(pt)) reason = "discard unsupported"; else if (data_limits->max_discard_sectors < pool->sectors_per_block) reason = "max discard sectors smaller than a block"; if (reason) { DMWARN("Data device (%s) %s: Disabling discard passdown.", bdevname(data_bdev, buf), reason); pt->adjusted_pf.discard_passdown = false; } } static int bind_control_target(struct pool *pool, struct dm_target *ti) { struct pool_c *pt = ti->private; /* * We want to make sure that a pool in PM_FAIL mode is never upgraded. */ enum pool_mode old_mode = get_pool_mode(pool); enum pool_mode new_mode = pt->adjusted_pf.mode; /* * Don't change the pool's mode until set_pool_mode() below. * Otherwise the pool's process_* function pointers may * not match the desired pool mode. */ pt->adjusted_pf.mode = old_mode; pool->ti = ti; pool->pf = pt->adjusted_pf; pool->low_water_blocks = pt->low_water_blocks; set_pool_mode(pool, new_mode); return 0; } static void unbind_control_target(struct pool *pool, struct dm_target *ti) { if (pool->ti == ti) pool->ti = NULL; } /*---------------------------------------------------------------- * Pool creation *--------------------------------------------------------------*/ /* Initialize pool features. */ static void pool_features_init(struct pool_features *pf) { pf->mode = PM_WRITE; pf->zero_new_blocks = true; pf->discard_enabled = true; pf->discard_passdown = true; pf->error_if_no_space = false; } static void __pool_destroy(struct pool *pool) { __pool_table_remove(pool); vfree(pool->cell_sort_array); if (dm_pool_metadata_close(pool->pmd) < 0) DMWARN("%s: dm_pool_metadata_close() failed.", __func__); dm_bio_prison_destroy(pool->prison); dm_kcopyd_client_destroy(pool->copier); if (pool->wq) destroy_workqueue(pool->wq); if (pool->next_mapping) mempool_free(pool->next_mapping, &pool->mapping_pool); mempool_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, 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_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, unsigned long block_size, int read_only, char **error, int *created) { struct pool *pool = __pool_table_lookup_metadata_dev(metadata_dev); if (pool) { if (pool->pool_md != pool_md) { *error = "metadata device already in use by a pool"; return ERR_PTR(-EBUSY); } __pool_inc(pool); } else { pool = __pool_table_lookup(pool_md); if (pool) { if (pool->md_dev != metadata_dev) { *error = "different pool cannot replace a pool"; return ERR_PTR(-EINVAL); } __pool_inc(pool); } else { pool = pool_create(pool_md, metadata_dev, block_size, read_only, error); *created = 1; } } return pool; } /*---------------------------------------------------------------- * Pool target methods *--------------------------------------------------------------*/ static void pool_dtr(struct dm_target *ti) { struct pool_c *pt = ti->private; mutex_lock(&dm_thin_pool_table.mutex); unbind_control_target(pt->pool, ti); __pool_dec(pt->pool); dm_put_device(ti, pt->metadata_dev); dm_put_device(ti, pt->data_dev); kfree(pt); mutex_unlock(&dm_thin_pool_table.mutex); } static int parse_pool_features(struct dm_arg_set *as, struct pool_features *pf, struct dm_target *ti) { int r; unsigned argc; const char *arg_name; static 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); } static sector_t get_dev_size(struct block_device *bdev) { return i_size_read(bdev->bd_inode) >> SECTOR_SHIFT; } static void warn_if_metadata_device_too_big(struct block_device *bdev) { sector_t metadata_dev_size = get_dev_size(bdev); char buffer[BDEVNAME_SIZE]; if (metadata_dev_size > THIN_METADATA_MAX_SECTORS_WARNING) DMWARN("Metadata device %s is larger than %u sectors: excess space will not be used.", bdevname(bdev, buffer), THIN_METADATA_MAX_SECTORS); } static sector_t get_metadata_dev_size(struct block_device *bdev) { sector_t metadata_dev_size = get_dev_size(bdev); if (metadata_dev_size > THIN_METADATA_MAX_SECTORS) metadata_dev_size = THIN_METADATA_MAX_SECTORS; return metadata_dev_size; } static dm_block_t get_metadata_dev_size_in_blocks(struct block_device *bdev) { sector_t metadata_dev_size = get_metadata_dev_size(bdev); sector_div(metadata_dev_size, THIN_METADATA_BLOCK_SIZE); return metadata_dev_size; } /* * When a metadata threshold is crossed a dm event is triggered, and * userland should respond by growing the metadata device. We could let * userland set the threshold, like we do with the data threshold, but I'm * not sure they know enough to do this well. */ static dm_block_t calc_metadata_threshold(struct pool_c *pt) { /* * 4M is ample for all ops with the possible exception of thin * device deletion which is harmless if it fails (just retry the * delete after you've grown the device). */ dm_block_t quarter = get_metadata_dev_size_in_blocks(pt->metadata_dev->bdev) / 4; return min((dm_block_t)1024ULL /* 4M */, quarter); } /* * thin-pool <metadata dev> <data dev> * <data block size (sectors)> * <low water mark (blocks)> * [<#feature args> [<arg>]*] * * Optional feature arguments are: * skip_block_zeroing: skips the zeroing of newly-provisioned blocks. * ignore_discard: disable discard * no_discard_passdown: don't pass discards down to the data device * read_only: Don't allow any changes to be made to the pool metadata. * error_if_no_space: error IOs, instead of queueing, if no space. */ static int pool_ctr(struct dm_target *ti, unsigned argc, char **argv) { int r, pool_created = 0; struct pool_c *pt; struct pool *pool; struct pool_features pf; struct dm_arg_set as; struct dm_dev *data_dev; unsigned long block_size; dm_block_t low_water_blocks; struct dm_dev *metadata_dev; fmode_t metadata_mode; /* * FIXME Remove validation from scope of lock. */ mutex_lock(&dm_thin_pool_table.mutex); if (argc < 4) { ti->error = "Invalid argument count"; r = -EINVAL; goto out_unlock; } as.argc = argc; as.argv = argv; /* * Set default pool features. */ pool_features_init(&pf); dm_consume_args(&as, 4); r = parse_pool_features(&as, &pf, ti); if (r) goto out_unlock; metadata_mode = FMODE_READ | ((pf.mode == PM_READ_ONLY) ? 0 : FMODE_WRITE); r = dm_get_device(ti, argv[0], metadata_mode, &metadata_dev); if (r) { ti->error = "Error opening metadata block device"; goto out_unlock; } warn_if_metadata_device_too_big(metadata_dev->bdev); r = dm_get_device(ti, argv[1], FMODE_READ | FMODE_WRITE, &data_dev); if (r) { ti->error = "Error getting data device"; goto out_metadata; } if (kstrtoul(argv[2], 10, &block_size) || !block_size || block_size < DATA_DEV_BLOCK_SIZE_MIN_SECTORS || block_size > DATA_DEV_BLOCK_SIZE_MAX_SECTORS || block_size & (DATA_DEV_BLOCK_SIZE_MIN_SECTORS - 1)) { ti->error = "Invalid block size"; r = -EINVAL; goto out; } if (kstrtoull(argv[3], 10, (unsigned long long *)&low_water_blocks)) { ti->error = "Invalid low water mark"; r = -EINVAL; goto out; } pt = kzalloc(sizeof(*pt), GFP_KERNEL); if (!pt) { r = -ENOMEM; goto out; } pool = __pool_find(dm_table_get_md(ti->table), metadata_dev->bdev, block_size, pf.mode == PM_READ_ONLY, &ti->error, &pool_created); if (IS_ERR(pool)) { r = PTR_ERR(pool); goto out_free_pt; } /* * 'pool_created' reflects whether this is the first table load. * Top level discard support is not allowed to be changed after * initial load. This would require a pool reload to trigger thin * device changes. */ if (!pool_created && pf.discard_enabled != pool->pf.discard_enabled) { ti->error = "Discard support cannot be disabled once enabled"; r = -EINVAL; goto out_flags_changed; } pt->pool = pool; pt->ti = ti; pt->metadata_dev = metadata_dev; pt->data_dev = data_dev; pt->low_water_blocks = low_water_blocks; pt->adjusted_pf = pt->requested_pf = pf; ti->num_flush_bios = 1; /* * Only need to enable discards if the pool should pass * them down to the data device. The thin device's discard * processing will cause mappings to be removed from the btree. */ if (pf.discard_enabled && pf.discard_passdown) { ti->num_discard_bios = 1; /* * Setting 'discards_supported' circumvents the normal * stacking of discard limits (this keeps the pool and * thin devices' discard limits consistent). */ ti->discards_supported = true; } ti->private = pt; r = dm_pool_register_metadata_threshold(pt->pool->pmd, calc_metadata_threshold(pt), metadata_low_callback, pool); if (r) goto out_flags_changed; pt->callbacks.congested_fn = pool_is_congested; dm_table_add_target_callbacks(ti->table, &pt->callbacks); mutex_unlock(&dm_thin_pool_table.mutex); return 0; out_flags_changed: __pool_dec(pool); out_free_pt: kfree(pt); out: dm_put_device(ti, data_dev); out_metadata: dm_put_device(ti, metadata_dev); out_unlock: mutex_unlock(&dm_thin_pool_table.mutex); return r; } static int pool_map(struct dm_target *ti, struct bio *bio) { int r; struct pool_c *pt = ti->private; struct pool *pool = pt->pool; unsigned long flags; /* * As this is a singleton target, ti->begin is always zero. */ spin_lock_irqsave(&pool->lock, flags); bio_set_dev(bio, pt->data_dev->bdev); r = DM_MAPIO_REMAPPED; spin_unlock_irqrestore(&pool->lock, flags); return r; } static int maybe_resize_data_dev(struct dm_target *ti, bool *need_commit) { int r; struct pool_c *pt = ti->private; struct pool *pool = pt->pool; sector_t data_size = ti->len; dm_block_t sb_data_size; *need_commit = false; (void) sector_div(data_size, pool->sectors_per_block); r = dm_pool_get_data_dev_size(pool->pmd, &sb_data_size); if (r) { DMERR("%s: failed to retrieve data device size", dm_device_name(pool->pool_md)); return r; } if (data_size < sb_data_size) { DMERR("%s: pool target (%llu blocks) too small: expected %llu", dm_device_name(pool->pool_md), (unsigned long long)data_size, sb_data_size); return -EINVAL; } else if (data_size > sb_data_size) { if (dm_pool_metadata_needs_check(pool->pmd)) { DMERR("%s: unable to grow the data device until repaired.", dm_device_name(pool->pool_md)); return 0; } if (sb_data_size) DMINFO("%s: growing the data device from %llu to %llu blocks", dm_device_name(pool->pool_md), sb_data_size, (unsigned long long)data_size); r = dm_pool_resize_data_dev(pool->pmd, data_size); if (r) { metadata_operation_failed(pool, "dm_pool_resize_data_dev", r); return r; } *need_commit = true; } return 0; } static int maybe_resize_metadata_dev(struct dm_target *ti, bool *need_commit) { int r; struct pool_c *pt = ti->private; struct pool *pool = pt->pool; dm_block_t metadata_dev_size, sb_metadata_dev_size; *need_commit = false; metadata_dev_size = get_metadata_dev_size_in_blocks(pool->md_dev); r = dm_pool_get_metadata_dev_size(pool->pmd, &sb_metadata_dev_size); if (r) { DMERR("%s: failed to retrieve metadata device size", dm_device_name(pool->pool_md)); return r; } if (metadata_dev_size < sb_metadata_dev_size) { DMERR("%s: metadata device (%llu blocks) too small: expected %llu", dm_device_name(pool->pool_md), metadata_dev_size, sb_metadata_dev_size); return -EINVAL; } else if (metadata_dev_size > sb_metadata_dev_size) { if (dm_pool_metadata_needs_check(pool->pmd)) { DMERR("%s: unable to grow the metadata device until repaired.", dm_device_name(pool->pool_md)); return 0; } warn_if_metadata_device_too_big(pool->md_dev); DMINFO("%s: growing the metadata device from %llu to %llu blocks", dm_device_name(pool->pool_md), sb_metadata_dev_size, metadata_dev_size); 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) return r; r = maybe_resize_data_dev(ti, &need_commit1); if (r) return r; r = maybe_resize_metadata_dev(ti, &need_commit2); if (r) return r; if (need_commit1 || need_commit2) (void) commit(pool); return 0; } static void pool_suspend_active_thins(struct pool *pool) { struct thin_c *tc; /* Suspend all active thin devices */ tc = get_first_thin(pool); while (tc) { dm_internal_suspend_noflush(tc->thin_md); tc = get_next_thin(pool, tc); } } static void pool_resume_active_thins(struct pool *pool) { struct thin_c *tc; /* Resume all active thin devices */ tc = get_first_thin(pool); while (tc) { dm_internal_resume(tc->thin_md); tc = get_next_thin(pool, tc); } } static void pool_resume(struct dm_target *ti) { struct pool_c *pt = ti->private; struct pool *pool = pt->pool; unsigned long flags; /* * Must requeue active_thins' bios and then resume * active_thins _before_ clearing 'suspend' flag. */ requeue_bios(pool); pool_resume_active_thins(pool); spin_lock_irqsave(&pool->lock, flags); pool->low_water_triggered = false; pool->suspended = false; spin_unlock_irqrestore(&pool->lock, flags); do_waker(&pool->waker.work); } static void pool_presuspend(struct dm_target *ti) { struct pool_c *pt = ti->private; struct pool *pool = pt->pool; unsigned long flags; spin_lock_irqsave(&pool->lock, flags); pool->suspended = true; spin_unlock_irqrestore(&pool->lock, flags); pool_suspend_active_thins(pool); } static void pool_presuspend_undo(struct dm_target *ti) { struct pool_c *pt = ti->private; struct pool *pool = pt->pool; unsigned long flags; pool_resume_active_thins(pool); spin_lock_irqsave(&pool->lock, flags); pool->suspended = false; spin_unlock_irqrestore(&pool->lock, flags); } static void pool_postsuspend(struct dm_target *ti) { struct pool_c *pt = ti->private; struct pool *pool = pt->pool; cancel_delayed_work_sync(&pool->waker); cancel_delayed_work_sync(&pool->no_space_timeout); flush_workqueue(pool->wq); (void) commit(pool); } static int check_arg_count(unsigned argc, unsigned args_required) { if (argc != args_required) { DMWARN("Message received with %u arguments instead of %u.", argc, args_required); return -EINVAL; } return 0; } static int read_dev_id(char *arg, dm_thin_id *dev_id, int warning) { if (!kstrtoull(arg, 10, (unsigned long long *)dev_id) && *dev_id <= MAX_DEV_ID) return 0; if (warning) DMWARN("Message received with invalid device id: %s", arg); return -EINVAL; } static int process_create_thin_mesg(unsigned argc, char **argv, struct pool *pool) { dm_thin_id dev_id; int r; r = check_arg_count(argc, 2); if (r) return r; r = read_dev_id(argv[1], &dev_id, 1); if (r) return r; r = dm_pool_create_thin(pool->pmd, dev_id); if (r) { DMWARN("Creation of new thinly-provisioned device with id %s failed.", argv[1]); return r; } return 0; } static int process_create_snap_mesg(unsigned argc, char **argv, struct pool *pool) { dm_thin_id dev_id; dm_thin_id origin_dev_id; int r; r = check_arg_count(argc, 3); if (r) return r; r = read_dev_id(argv[1], &dev_id, 1); if (r) return r; r = read_dev_id(argv[2], &origin_dev_id, 1); if (r) return r; r = dm_pool_create_snap(pool->pmd, dev_id, origin_dev_id); if (r) { DMWARN("Creation of new snapshot %s of device %s failed.", argv[1], argv[2]); return r; } return 0; } static int process_delete_mesg(unsigned argc, char **argv, struct pool *pool) { dm_thin_id dev_id; int r; r = check_arg_count(argc, 2); if (r) return r; r = read_dev_id(argv[1], &dev_id, 1); if (r) return r; r = dm_pool_delete_thin_device(pool->pmd, dev_id); if (r) DMWARN("Deletion of thin device %s failed.", argv[1]); return r; } static int process_set_transaction_id_mesg(unsigned argc, char **argv, struct pool *pool) { dm_thin_id old_id, new_id; int r; r = check_arg_count(argc, 3); if (r) return r; if (kstrtoull(argv[1], 10, (unsigned long long *)&old_id)) { DMWARN("set_transaction_id message: Unrecognised id %s.", argv[1]); return -EINVAL; } if (kstrtoull(argv[2], 10, (unsigned long long *)&new_id)) { DMWARN("set_transaction_id message: Unrecognised new id %s.", argv[2]); return -EINVAL; } r = dm_pool_set_metadata_transaction_id(pool->pmd, old_id, new_id); if (r) { DMWARN("Failed to change transaction id from %s to %s.", argv[1], argv[2]); return r; } return 0; } static int process_reserve_metadata_snap_mesg(unsigned argc, char **argv, struct pool *pool) { int r; r = check_arg_count(argc, 1); if (r) return r; (void) commit(pool); r = dm_pool_reserve_metadata_snap(pool->pmd); if (r) DMWARN("reserve_metadata_snap message failed."); return r; } static int process_release_metadata_snap_mesg(unsigned argc, char **argv, struct pool *pool) { int r; r = check_arg_count(argc, 1); if (r) return r; r = dm_pool_release_metadata_snap(pool->pmd); if (r) DMWARN("release_metadata_snap message failed."); return r; } /* * Messages supported: * create_thin <dev_id> * create_snap <dev_id> <origin_id> * delete <dev_id> * set_transaction_id <current_trans_id> <new_trans_id> * reserve_metadata_snap * release_metadata_snap */ static int pool_message(struct dm_target *ti, unsigned argc, char **argv, char *result, unsigned 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 sz, unsigned maxlen) { unsigned count = !pf->zero_new_blocks + !pf->discard_enabled + !pf->discard_passdown + (pf->mode == PM_READ_ONLY) + pf->error_if_no_space; DMEMIT("%u ", count); if (!pf->zero_new_blocks) DMEMIT("skip_block_zeroing "); if (!pf->discard_enabled) DMEMIT("ignore_discard "); if (!pf->discard_passdown) DMEMIT("no_discard_passdown "); if (pf->mode == PM_READ_ONLY) DMEMIT("read_only "); if (pf->error_if_no_space) DMEMIT("error_if_no_space "); } /* * Status line is: * <transaction id> <used metadata sectors>/<total metadata sectors> * <used data sectors>/<total data sectors> <held metadata root> * <pool mode> <discard config> <no space config> <needs_check> */ static void pool_status(struct dm_target *ti, status_type_t type, unsigned status_flags, char *result, unsigned maxlen) { int r; unsigned sz = 0; uint64_t transaction_id; dm_block_t nr_free_blocks_data; dm_block_t nr_free_blocks_metadata; dm_block_t nr_blocks_data; dm_block_t nr_blocks_metadata; dm_block_t held_root; 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; } return; err: DMEMIT("Error"); } static int pool_iterate_devices(struct dm_target *ti, iterate_devices_callout_fn fn, void *data) { struct pool_c *pt = ti->private; return fn(ti, pt->data_dev, 0, ti->len, data); } static void pool_io_hints(struct dm_target *ti, struct queue_limits *limits) { struct pool_c *pt = ti->private; struct pool *pool = pt->pool; sector_t io_opt_sectors = limits->io_opt >> SECTOR_SHIFT; /* * If max_sectors is smaller than pool->sectors_per_block adjust it * to the highest possible power-of-2 factor of pool->sectors_per_block. * This is especially beneficial when the pool's data device is a RAID * device that has a full stripe width that matches pool->sectors_per_block * -- because even though partial RAID stripe-sized IOs will be issued to a * single RAID stripe; when aggregated they will end on a full RAID stripe * boundary.. which avoids additional partial RAID stripe writes cascading */ if (limits->max_sectors < pool->sectors_per_block) { while (!is_factor(pool->sectors_per_block, limits->max_sectors)) { if ((limits->max_sectors & (limits->max_sectors - 1)) == 0) limits->max_sectors--; limits->max_sectors = rounddown_pow_of_two(limits->max_sectors); } } /* * If the system-determined stacked limits are compatible with the * pool's blocksize (io_opt is a factor) do not override them. */ if (io_opt_sectors < pool->sectors_per_block || !is_factor(io_opt_sectors, pool->sectors_per_block)) { if (is_factor(pool->sectors_per_block, limits->max_sectors)) blk_limits_io_min(limits, limits->max_sectors << SECTOR_SHIFT); else blk_limits_io_min(limits, pool->sectors_per_block << SECTOR_SHIFT); blk_limits_io_opt(limits, pool->sectors_per_block << SECTOR_SHIFT); } /* * pt->adjusted_pf is a staging area for the actual features to use. * They get transferred to the live pool in bind_control_target() * called from pool_preresume(). */ if (!pt->adjusted_pf.discard_enabled) { /* * Must explicitly disallow stacking discard limits otherwise the * block layer will stack them if pool's data device has support. * QUEUE_FLAG_DISCARD wouldn't be set but there is no way for the * user to see that, so make sure to set all discard limits to 0. */ limits->discard_granularity = 0; return; } disable_passdown_if_not_supported(pt); /* * The pool uses the same discard limits as the underlying data * device. DM core has already set this up. */ } static struct target_type pool_target = { .name = "thin-pool", .features = DM_TARGET_SINGLETON | DM_TARGET_ALWAYS_WRITEABLE | DM_TARGET_IMMUTABLE, .version = {1, 21, 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; unsigned long flags; spin_lock_irqsave(&tc->pool->lock, flags); list_del_rcu(&tc->list); spin_unlock_irqrestore(&tc->pool->lock, flags); synchronize_rcu(); thin_put(tc); wait_for_completion(&tc->can_destroy); mutex_lock(&dm_thin_pool_table.mutex); __pool_dec(tc->pool); dm_pool_close_thin_device(tc->td); dm_put_device(ti, tc->pool_dev); if (tc->origin_dev) dm_put_device(ti, tc->origin_dev); kfree(tc); mutex_unlock(&dm_thin_pool_table.mutex); } /* * Thin target parameters: * * <pool_dev> <dev_id> [origin_dev] * * pool_dev: the path to the pool (eg, /dev/mapper/my_pool) * dev_id: the internal device identifier * origin_dev: a device external to the pool that should act as the origin * * If the pool device has discards disabled, they get disabled for the thin * device as well. */ static int thin_ctr(struct dm_target *ti, unsigned argc, char **argv) { int r; struct thin_c *tc; struct dm_dev *pool_dev, *origin_dev; struct mapped_device *pool_md; unsigned long flags; mutex_lock(&dm_thin_pool_table.mutex); if (argc != 2 && argc != 3) { ti->error = "Invalid argument count"; r = -EINVAL; goto out_unlock; } tc = ti->private = kzalloc(sizeof(*tc), GFP_KERNEL); if (!tc) { ti->error = "Out of memory"; r = -ENOMEM; goto out_unlock; } tc->thin_md = dm_table_get_md(ti->table); spin_lock_init(&tc->lock); INIT_LIST_HEAD(&tc->deferred_cells); bio_list_init(&tc->deferred_bio_list); bio_list_init(&tc->retry_on_resume_list); tc->sort_bio_list = RB_ROOT; if (argc == 3) { r = dm_get_device(ti, argv[2], FMODE_READ, &origin_dev); if (r) { ti->error = "Error opening origin device"; goto bad_origin_dev; } tc->origin_dev = origin_dev; } r = dm_get_device(ti, argv[0], dm_table_get_mode(ti->table), &pool_dev); if (r) { ti->error = "Error opening pool device"; goto bad_pool_dev; } tc->pool_dev = pool_dev; if (read_dev_id(argv[1], (unsigned long long *)&tc->dev_id, 0)) { ti->error = "Invalid device id"; r = -EINVAL; goto bad_common; } pool_md = dm_get_md(tc->pool_dev->bdev->bd_dev); if (!pool_md) { ti->error = "Couldn't get pool mapped device"; r = -EINVAL; goto bad_common; } tc->pool = __pool_table_lookup(pool_md); if (!tc->pool) { ti->error = "Couldn't find pool object"; r = -EINVAL; goto bad_pool_lookup; } __pool_inc(tc->pool); if (get_pool_mode(tc->pool) == PM_FAIL) { ti->error = "Couldn't open thin device, Pool is in fail mode"; r = -EINVAL; goto bad_pool; } r = dm_pool_open_thin_device(tc->pool->pmd, tc->dev_id, &tc->td); if (r) { ti->error = "Couldn't open thin internal device"; goto bad_pool; } r = dm_set_target_max_io_len(ti, tc->pool->sectors_per_block); if (r) goto bad; ti->num_flush_bios = 1; ti->flush_supported = true; ti->per_io_data_size = sizeof(struct dm_thin_endio_hook); /* In case the pool supports discards, pass them on. */ if (tc->pool->pf.discard_enabled) { ti->discards_supported = true; ti->num_discard_bios = 1; ti->split_discard_bios = false; } mutex_unlock(&dm_thin_pool_table.mutex); spin_lock_irqsave(&tc->pool->lock, flags); if (tc->pool->suspended) { spin_unlock_irqrestore(&tc->pool->lock, flags); mutex_lock(&dm_thin_pool_table.mutex); /* reacquire for __pool_dec */ ti->error = "Unable to activate thin device while pool is suspended"; r = -EINVAL; goto bad; } refcount_set(&tc->refcount, 1); init_completion(&tc->can_destroy); list_add_tail_rcu(&tc->list, &tc->pool->active_thins); spin_unlock_irqrestore(&tc->pool->lock, flags); /* * This synchronize_rcu() call is needed here otherwise we risk a * wake_worker() call finding no bios to process (because the newly * added tc isn't yet visible). So this reduces latency since we * aren't then dependent on the periodic commit to wake_worker(). */ synchronize_rcu(); dm_put(pool_md); return 0; bad: dm_pool_close_thin_device(tc->td); bad_pool: __pool_dec(tc->pool); bad_pool_lookup: dm_put(pool_md); bad_common: dm_put_device(ti, tc->pool_dev); bad_pool_dev: if (tc->origin_dev) dm_put_device(ti, tc->origin_dev); bad_origin_dev: kfree(tc); out_unlock: mutex_unlock(&dm_thin_pool_table.mutex); return r; } static int thin_map(struct dm_target *ti, struct bio *bio) { bio->bi_iter.bi_sector = dm_target_offset(ti, bio->bi_iter.bi_sector); return thin_bio_map(ti, bio); } static int thin_endio(struct dm_target *ti, struct bio *bio, 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 status_flags, char *result, unsigned maxlen) { int r; ssize_t sz = 0; dm_block_t mapped, highest; char buf[BDEVNAME_SIZE]; struct thin_c *tc = ti->private; if (get_pool_mode(tc->pool) == PM_FAIL) { DMEMIT("Fail"); return; } if (!tc->td) DMEMIT("-"); else { switch (type) { case STATUSTYPE_INFO: r = dm_thin_get_mapped_count(tc->td, &mapped); if (r) { DMERR("dm_thin_get_mapped_count returned %d", r); goto err; } r = dm_thin_get_highest_mapped_block(tc->td, &highest); if (r < 0) { DMERR("dm_thin_get_highest_mapped_block returned %d", r); goto err; } DMEMIT("%llu ", mapped * tc->pool->sectors_per_block); if (r) DMEMIT("%llu", ((highest + 1) * tc->pool->sectors_per_block) - 1); else DMEMIT("-"); break; case STATUSTYPE_TABLE: DMEMIT("%s %lu", format_dev_t(buf, tc->pool_dev->bdev->bd_dev), (unsigned long) tc->dev_id); if (tc->origin_dev) DMEMIT(" %s", format_dev_t(buf, tc->origin_dev->bdev->bd_dev)); break; } } return; err: DMEMIT("Error"); } static int thin_iterate_devices(struct dm_target *ti, iterate_devices_callout_fn fn, void *data) { sector_t blocks; struct thin_c *tc = ti->private; struct pool *pool = tc->pool; /* * We can't call dm_pool_get_data_dev_size() since that blocks. So * we follow a more convoluted path through to the pool's target. */ if (!pool->ti) return 0; /* nothing is bound */ blocks = pool->ti->len; (void) sector_div(blocks, pool->sectors_per_block); if (blocks) return fn(ti, tc->pool_dev, 0, pool->sectors_per_block * blocks, data); return 0; } static void thin_io_hints(struct dm_target *ti, struct queue_limits *limits) { struct thin_c *tc = ti->private; struct pool *pool = tc->pool; if (!pool->pf.discard_enabled) return; limits->discard_granularity = pool->sectors_per_block << SECTOR_SHIFT; limits->max_discard_sectors = 2048 * 1024 * 16; /* 16G */ } static struct target_type thin_target = { .name = "thin", .version = {1, 21, 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");
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