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-rw-r--r--drivers/md/dm-thin.c4107
1 files changed, 4107 insertions, 0 deletions
diff --git a/drivers/md/dm-thin.c b/drivers/md/dm-thin.c
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+++ b/drivers/md/dm-thin.c
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+/*
+ * Copyright (C) 2011-2012 Red Hat UK.
+ *
+ * This file is released under the GPL.
+ */
+
+#include "dm-thin-metadata.h"
+#include "dm-bio-prison.h"
+#include "dm.h"
+
+#include <linux/device-mapper.h>
+#include <linux/dm-io.h>
+#include <linux/dm-kcopyd.h>
+#include <linux/jiffies.h>
+#include <linux/log2.h>
+#include <linux/list.h>
+#include <linux/rculist.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/vmalloc.h>
+#include <linux/sort.h>
+#include <linux/rbtree.h>
+
+#define DM_MSG_PREFIX "thin"
+
+/*
+ * Tunable constants
+ */
+#define ENDIO_HOOK_POOL_SIZE 1024
+#define MAPPING_POOL_SIZE 1024
+#define COMMIT_PERIOD HZ
+#define NO_SPACE_TIMEOUT_SECS 60
+
+static unsigned no_space_timeout_secs = NO_SPACE_TIMEOUT_SECS;
+
+DECLARE_DM_KCOPYD_THROTTLE_WITH_MODULE_PARM(snapshot_copy_throttle,
+ "A percentage of time allocated for copy on write");
+
+/*
+ * The block size of the device holding pool data must be
+ * between 64KB and 1GB.
+ */
+#define DATA_DEV_BLOCK_SIZE_MIN_SECTORS (64 * 1024 >> SECTOR_SHIFT)
+#define DATA_DEV_BLOCK_SIZE_MAX_SECTORS (1024 * 1024 * 1024 >> SECTOR_SHIFT)
+
+/*
+ * Device id is restricted to 24 bits.
+ */
+#define MAX_DEV_ID ((1 << 24) - 1)
+
+/*
+ * How do we handle breaking sharing of data blocks?
+ * =================================================
+ *
+ * We use a standard copy-on-write btree to store the mappings for the
+ * devices (note I'm talking about copy-on-write of the metadata here, not
+ * the data). When you take an internal snapshot you clone the root node
+ * of the origin btree. After this there is no concept of an origin or a
+ * snapshot. They are just two device trees that happen to point to the
+ * same data blocks.
+ *
+ * When we get a write in we decide if it's to a shared data block using
+ * some timestamp magic. If it is, we have to break sharing.
+ *
+ * Let's say we write to a shared block in what was the origin. The
+ * steps are:
+ *
+ * i) plug io further to this physical block. (see bio_prison code).
+ *
+ * ii) quiesce any read io to that shared data block. Obviously
+ * including all devices that share this block. (see dm_deferred_set code)
+ *
+ * iii) copy the data block to a newly allocate block. This step can be
+ * missed out if the io covers the block. (schedule_copy).
+ *
+ * iv) insert the new mapping into the origin's btree
+ * (process_prepared_mapping). This act of inserting breaks some
+ * sharing of btree nodes between the two devices. Breaking sharing only
+ * effects the btree of that specific device. Btrees for the other
+ * devices that share the block never change. The btree for the origin
+ * device as it was after the last commit is untouched, ie. we're using
+ * persistent data structures in the functional programming sense.
+ *
+ * v) unplug io to this physical block, including the io that triggered
+ * the breaking of sharing.
+ *
+ * Steps (ii) and (iii) occur in parallel.
+ *
+ * The metadata _doesn't_ need to be committed before the io continues. We
+ * get away with this because the io is always written to a _new_ block.
+ * If there's a crash, then:
+ *
+ * - The origin mapping will point to the old origin block (the shared
+ * one). This will contain the data as it was before the io that triggered
+ * the breaking of sharing came in.
+ *
+ * - The snap mapping still points to the old block. As it would after
+ * the commit.
+ *
+ * The downside of this scheme is the timestamp magic isn't perfect, and
+ * will continue to think that data block in the snapshot device is shared
+ * even after the write to the origin has broken sharing. I suspect data
+ * blocks will typically be shared by many different devices, so we're
+ * breaking sharing n + 1 times, rather than n, where n is the number of
+ * devices that reference this data block. At the moment I think the
+ * benefits far, far outweigh the disadvantages.
+ */
+
+/*----------------------------------------------------------------*/
+
+/*
+ * Key building.
+ */
+static void build_data_key(struct dm_thin_device *td,
+ dm_block_t b, struct dm_cell_key *key)
+{
+ key->virtual = 0;
+ key->dev = dm_thin_dev_id(td);
+ key->block_begin = b;
+ key->block_end = b + 1ULL;
+}
+
+static void build_virtual_key(struct dm_thin_device *td, dm_block_t b,
+ struct dm_cell_key *key)
+{
+ key->virtual = 1;
+ key->dev = dm_thin_dev_id(td);
+ key->block_begin = b;
+ key->block_end = b + 1ULL;
+}
+
+/*----------------------------------------------------------------*/
+
+#define THROTTLE_THRESHOLD (1 * HZ)
+
+struct throttle {
+ struct rw_semaphore lock;
+ unsigned long threshold;
+ bool throttle_applied;
+};
+
+static void throttle_init(struct throttle *t)
+{
+ init_rwsem(&t->lock);
+ t->throttle_applied = false;
+}
+
+static void throttle_work_start(struct throttle *t)
+{
+ t->threshold = jiffies + THROTTLE_THRESHOLD;
+}
+
+static void throttle_work_update(struct throttle *t)
+{
+ if (!t->throttle_applied && jiffies > t->threshold) {
+ down_write(&t->lock);
+ t->throttle_applied = true;
+ }
+}
+
+static void throttle_work_complete(struct throttle *t)
+{
+ if (t->throttle_applied) {
+ t->throttle_applied = false;
+ up_write(&t->lock);
+ }
+}
+
+static void throttle_lock(struct throttle *t)
+{
+ down_read(&t->lock);
+}
+
+static void throttle_unlock(struct throttle *t)
+{
+ up_read(&t->lock);
+}
+
+/*----------------------------------------------------------------*/
+
+/*
+ * A pool device ties together a metadata device and a data device. It
+ * also provides the interface for creating and destroying internal
+ * devices.
+ */
+struct dm_thin_new_mapping;
+
+/*
+ * The pool runs in 4 modes. Ordered in degraded order for comparisons.
+ */
+enum pool_mode {
+ PM_WRITE, /* metadata may be changed */
+ PM_OUT_OF_DATA_SPACE, /* metadata may be changed, though data may not be allocated */
+ PM_READ_ONLY, /* metadata may not be changed */
+ PM_FAIL, /* all I/O fails */
+};
+
+struct pool_features {
+ enum pool_mode mode;
+
+ bool zero_new_blocks:1;
+ bool discard_enabled:1;
+ bool discard_passdown:1;
+ bool error_if_no_space:1;
+};
+
+struct thin_c;
+typedef void (*process_bio_fn)(struct thin_c *tc, struct bio *bio);
+typedef void (*process_cell_fn)(struct thin_c *tc, struct dm_bio_prison_cell *cell);
+typedef void (*process_mapping_fn)(struct dm_thin_new_mapping *m);
+
+#define CELL_SORT_ARRAY_SIZE 8192
+
+struct pool {
+ struct list_head list;
+ struct dm_target *ti; /* Only set if a pool target is bound */
+
+ struct mapped_device *pool_md;
+ struct block_device *md_dev;
+ struct dm_pool_metadata *pmd;
+
+ dm_block_t low_water_blocks;
+ uint32_t sectors_per_block;
+ int sectors_per_block_shift;
+
+ struct pool_features pf;
+ bool low_water_triggered:1; /* A dm event has been sent */
+ bool suspended:1;
+
+ struct dm_bio_prison *prison;
+ struct dm_kcopyd_client *copier;
+
+ struct workqueue_struct *wq;
+ struct throttle throttle;
+ struct work_struct worker;
+ struct delayed_work waker;
+ struct delayed_work no_space_timeout;
+
+ unsigned long last_commit_jiffies;
+ unsigned ref_count;
+
+ spinlock_t lock;
+ struct bio_list deferred_flush_bios;
+ struct list_head prepared_mappings;
+ struct list_head prepared_discards;
+ struct list_head active_thins;
+
+ struct dm_deferred_set *shared_read_ds;
+ struct dm_deferred_set *all_io_ds;
+
+ struct dm_thin_new_mapping *next_mapping;
+ mempool_t *mapping_pool;
+
+ process_bio_fn process_bio;
+ process_bio_fn process_discard;
+
+ process_cell_fn process_cell;
+ process_cell_fn process_discard_cell;
+
+ process_mapping_fn process_prepared_mapping;
+ process_mapping_fn process_prepared_discard;
+
+ struct dm_bio_prison_cell **cell_sort_array;
+};
+
+static enum pool_mode get_pool_mode(struct pool *pool);
+static void metadata_operation_failed(struct pool *pool, const char *op, int r);
+
+/*
+ * Target context for a pool.
+ */
+struct pool_c {
+ struct dm_target *ti;
+ struct pool *pool;
+ struct dm_dev *data_dev;
+ struct dm_dev *metadata_dev;
+ struct dm_target_callbacks callbacks;
+
+ dm_block_t low_water_blocks;
+ struct pool_features requested_pf; /* Features requested during table load */
+ struct pool_features adjusted_pf; /* Features used after adjusting for constituent devices */
+};
+
+/*
+ * Target context for a thin.
+ */
+struct thin_c {
+ struct list_head list;
+ struct dm_dev *pool_dev;
+ struct dm_dev *origin_dev;
+ sector_t origin_size;
+ dm_thin_id dev_id;
+
+ struct pool *pool;
+ struct dm_thin_device *td;
+ struct mapped_device *thin_md;
+
+ bool requeue_mode:1;
+ spinlock_t lock;
+ struct list_head deferred_cells;
+ struct bio_list deferred_bio_list;
+ struct bio_list retry_on_resume_list;
+ struct rb_root sort_bio_list; /* sorted list of deferred bios */
+
+ /*
+ * Ensures the thin is not destroyed until the worker has finished
+ * iterating the active_thins list.
+ */
+ atomic_t refcount;
+ struct completion can_destroy;
+};
+
+/*----------------------------------------------------------------*/
+
+/*
+ * wake_worker() is used when new work is queued and when pool_resume is
+ * ready to continue deferred IO processing.
+ */
+static void wake_worker(struct pool *pool)
+{
+ queue_work(pool->wq, &pool->worker);
+}
+
+/*----------------------------------------------------------------*/
+
+static int bio_detain(struct pool *pool, struct dm_cell_key *key, struct bio *bio,
+ struct dm_bio_prison_cell **cell_result)
+{
+ int r;
+ struct dm_bio_prison_cell *cell_prealloc;
+
+ /*
+ * Allocate a cell from the prison's mempool.
+ * This might block but it can't fail.
+ */
+ cell_prealloc = dm_bio_prison_alloc_cell(pool->prison, GFP_NOIO);
+
+ r = dm_bio_detain(pool->prison, key, bio, cell_prealloc, cell_result);
+ if (r)
+ /*
+ * We reused an old cell; we can get rid of
+ * the new one.
+ */
+ dm_bio_prison_free_cell(pool->prison, cell_prealloc);
+
+ return r;
+}
+
+static void cell_release(struct pool *pool,
+ struct dm_bio_prison_cell *cell,
+ struct bio_list *bios)
+{
+ dm_cell_release(pool->prison, cell, bios);
+ dm_bio_prison_free_cell(pool->prison, cell);
+}
+
+static void cell_visit_release(struct pool *pool,
+ void (*fn)(void *, struct dm_bio_prison_cell *),
+ void *context,
+ struct dm_bio_prison_cell *cell)
+{
+ dm_cell_visit_release(pool->prison, fn, context, cell);
+ dm_bio_prison_free_cell(pool->prison, cell);
+}
+
+static void cell_release_no_holder(struct pool *pool,
+ struct dm_bio_prison_cell *cell,
+ struct bio_list *bios)
+{
+ dm_cell_release_no_holder(pool->prison, cell, bios);
+ dm_bio_prison_free_cell(pool->prison, cell);
+}
+
+static void cell_error_with_code(struct pool *pool,
+ struct dm_bio_prison_cell *cell, int error_code)
+{
+ dm_cell_error(pool->prison, cell, error_code);
+ dm_bio_prison_free_cell(pool->prison, cell);
+}
+
+static void cell_error(struct pool *pool, struct dm_bio_prison_cell *cell)
+{
+ cell_error_with_code(pool, cell, -EIO);
+}
+
+static void cell_success(struct pool *pool, struct dm_bio_prison_cell *cell)
+{
+ cell_error_with_code(pool, cell, 0);
+}
+
+static void cell_requeue(struct pool *pool, struct dm_bio_prison_cell *cell)
+{
+ cell_error_with_code(pool, cell, DM_ENDIO_REQUEUE);
+}
+
+/*----------------------------------------------------------------*/
+
+/*
+ * A global list of pools that uses a struct mapped_device as a key.
+ */
+static struct dm_thin_pool_table {
+ struct mutex mutex;
+ struct list_head pools;
+} dm_thin_pool_table;
+
+static void pool_table_init(void)
+{
+ mutex_init(&dm_thin_pool_table.mutex);
+ INIT_LIST_HEAD(&dm_thin_pool_table.pools);
+}
+
+static void __pool_table_insert(struct pool *pool)
+{
+ BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
+ list_add(&pool->list, &dm_thin_pool_table.pools);
+}
+
+static void __pool_table_remove(struct pool *pool)
+{
+ BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
+ list_del(&pool->list);
+}
+
+static struct pool *__pool_table_lookup(struct mapped_device *md)
+{
+ struct pool *pool = NULL, *tmp;
+
+ BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
+
+ list_for_each_entry(tmp, &dm_thin_pool_table.pools, list) {
+ if (tmp->pool_md == md) {
+ pool = tmp;
+ break;
+ }
+ }
+
+ return pool;
+}
+
+static struct pool *__pool_table_lookup_metadata_dev(struct block_device *md_dev)
+{
+ struct pool *pool = NULL, *tmp;
+
+ BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
+
+ list_for_each_entry(tmp, &dm_thin_pool_table.pools, list) {
+ if (tmp->md_dev == md_dev) {
+ pool = tmp;
+ break;
+ }
+ }
+
+ return pool;
+}
+
+/*----------------------------------------------------------------*/
+
+struct dm_thin_endio_hook {
+ struct thin_c *tc;
+ struct dm_deferred_entry *shared_read_entry;
+ struct dm_deferred_entry *all_io_entry;
+ struct dm_thin_new_mapping *overwrite_mapping;
+ struct rb_node rb_node;
+};
+
+static void __merge_bio_list(struct bio_list *bios, struct bio_list *master)
+{
+ bio_list_merge(bios, master);
+ bio_list_init(master);
+}
+
+static void error_bio_list(struct bio_list *bios, int error)
+{
+ struct bio *bio;
+
+ while ((bio = bio_list_pop(bios)))
+ bio_endio(bio, error);
+}
+
+static void error_thin_bio_list(struct thin_c *tc, struct bio_list *master, int error)
+{
+ struct bio_list bios;
+ unsigned long flags;
+
+ bio_list_init(&bios);
+
+ spin_lock_irqsave(&tc->lock, flags);
+ __merge_bio_list(&bios, master);
+ spin_unlock_irqrestore(&tc->lock, flags);
+
+ error_bio_list(&bios, error);
+}
+
+static void requeue_deferred_cells(struct thin_c *tc)
+{
+ struct pool *pool = tc->pool;
+ unsigned long flags;
+ struct list_head cells;
+ struct dm_bio_prison_cell *cell, *tmp;
+
+ INIT_LIST_HEAD(&cells);
+
+ spin_lock_irqsave(&tc->lock, flags);
+ list_splice_init(&tc->deferred_cells, &cells);
+ spin_unlock_irqrestore(&tc->lock, flags);
+
+ list_for_each_entry_safe(cell, tmp, &cells, user_list)
+ cell_requeue(pool, cell);
+}
+
+static void requeue_io(struct thin_c *tc)
+{
+ struct bio_list bios;
+ unsigned long flags;
+
+ bio_list_init(&bios);
+
+ spin_lock_irqsave(&tc->lock, flags);
+ __merge_bio_list(&bios, &tc->deferred_bio_list);
+ __merge_bio_list(&bios, &tc->retry_on_resume_list);
+ spin_unlock_irqrestore(&tc->lock, flags);
+
+ error_bio_list(&bios, DM_ENDIO_REQUEUE);
+ requeue_deferred_cells(tc);
+}
+
+static void error_retry_list(struct pool *pool)
+{
+ 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, -EIO);
+ rcu_read_unlock();
+}
+
+/*
+ * 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 bool block_size_is_power_of_two(struct pool *pool)
+{
+ return pool->sectors_per_block_shift >= 0;
+}
+
+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;
+}
+
+static void remap(struct thin_c *tc, struct bio *bio, dm_block_t block)
+{
+ struct pool *pool = tc->pool;
+ sector_t bi_sector = bio->bi_iter.bi_sector;
+
+ bio->bi_bdev = tc->pool_dev->bdev;
+ if (block_size_is_power_of_two(pool))
+ bio->bi_iter.bi_sector =
+ (block << pool->sectors_per_block_shift) |
+ (bi_sector & (pool->sectors_per_block - 1));
+ else
+ bio->bi_iter.bi_sector = (block * pool->sectors_per_block) +
+ sector_div(bi_sector, pool->sectors_per_block);
+}
+
+static void remap_to_origin(struct thin_c *tc, struct bio *bio)
+{
+ bio->bi_bdev = tc->origin_dev->bdev;
+}
+
+static int bio_triggers_commit(struct thin_c *tc, struct bio *bio)
+{
+ return (bio->bi_rw & (REQ_FLUSH | REQ_FUA)) &&
+ 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->bi_rw & REQ_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 definitely_not_shared:1;
+
+ /*
+ * Track quiescing, copying and zeroing preparation actions. When this
+ * counter hits zero the block is prepared and can be inserted into the
+ * btree.
+ */
+ atomic_t prepare_actions;
+
+ int err;
+ struct thin_c *tc;
+ dm_block_t virt_block;
+ dm_block_t data_block;
+ struct dm_bio_prison_cell *cell, *cell2;
+
+ /*
+ * If the bio covers the whole area of a block then we can avoid
+ * zeroing or copying. Instead this bio is hooked. The bio will
+ * still be in the cell, so care has to be taken to avoid issuing
+ * the bio twice.
+ */
+ struct bio *bio;
+ bio_end_io_t *saved_bi_end_io;
+};
+
+static void __complete_mapping_preparation(struct dm_thin_new_mapping *m)
+{
+ struct pool *pool = m->tc->pool;
+
+ if (atomic_dec_and_test(&m->prepare_actions)) {
+ list_add_tail(&m->list, &pool->prepared_mappings);
+ wake_worker(pool);
+ }
+}
+
+static void complete_mapping_preparation(struct dm_thin_new_mapping *m)
+{
+ unsigned long flags;
+ struct pool *pool = m->tc->pool;
+
+ spin_lock_irqsave(&pool->lock, flags);
+ __complete_mapping_preparation(m);
+ spin_unlock_irqrestore(&pool->lock, flags);
+}
+
+static void copy_complete(int read_err, unsigned long write_err, void *context)
+{
+ struct dm_thin_new_mapping *m = context;
+
+ m->err = read_err || write_err ? -EIO : 0;
+ complete_mapping_preparation(m);
+}
+
+static void overwrite_endio(struct bio *bio, int err)
+{
+ 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;
+
+ m->err = err;
+ 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 (bio->bi_rw & (REQ_DISCARD | REQ_FLUSH | REQ_FUA))
+ 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)
+{
+ if (m->bio) {
+ m->bio->bi_end_io = m->saved_bi_end_io;
+ atomic_inc(&m->bio->bi_remaining);
+ }
+ cell_error(m->tc->pool, m->cell);
+ list_del(&m->list);
+ mempool_free(m, m->tc->pool->mapping_pool);
+}
+
+static void process_prepared_mapping(struct dm_thin_new_mapping *m)
+{
+ struct thin_c *tc = m->tc;
+ struct pool *pool = tc->pool;
+ struct bio *bio;
+ int r;
+
+ bio = m->bio;
+ if (bio) {
+ bio->bi_end_io = m->saved_bi_end_io;
+ atomic_inc(&bio->bi_remaining);
+ }
+
+ if (m->err) {
+ cell_error(pool, m->cell);
+ goto out;
+ }
+
+ /*
+ * Commit the prepared block into the mapping btree.
+ * Any I/O for this block arriving after this point will get
+ * remapped to it directly.
+ */
+ r = dm_thin_insert_block(tc->td, m->virt_block, m->data_block);
+ if (r) {
+ metadata_operation_failed(pool, "dm_thin_insert_block", r);
+ cell_error(pool, m->cell);
+ goto out;
+ }
+
+ /*
+ * Release any bios held while the block was being provisioned.
+ * If we are processing a write bio that completely covers the block,
+ * we already processed it so can ignore it now when processing
+ * the bios in the cell.
+ */
+ if (bio) {
+ inc_remap_and_issue_cell(tc, m->cell, m->data_block);
+ bio_endio(bio, 0);
+ } 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 process_prepared_discard_fail(struct dm_thin_new_mapping *m)
+{
+ struct thin_c *tc = m->tc;
+
+ bio_io_error(m->bio);
+ cell_defer_no_holder(tc, m->cell);
+ cell_defer_no_holder(tc, m->cell2);
+ mempool_free(m, tc->pool->mapping_pool);
+}
+
+static void process_prepared_discard_passdown(struct dm_thin_new_mapping *m)
+{
+ struct thin_c *tc = m->tc;
+
+ inc_all_io_entry(tc->pool, m->bio);
+ cell_defer_no_holder(tc, m->cell);
+ cell_defer_no_holder(tc, m->cell2);
+
+ if (m->pass_discard)
+ if (m->definitely_not_shared)
+ remap_and_issue(tc, m->bio, m->data_block);
+ else {
+ bool used = false;
+ if (dm_pool_block_is_used(tc->pool->pmd, m->data_block, &used) || used)
+ bio_endio(m->bio, 0);
+ else
+ remap_and_issue(tc, m->bio, m->data_block);
+ }
+ else
+ bio_endio(m->bio, 0);
+
+ mempool_free(m, tc->pool->mapping_pool);
+}
+
+static void process_prepared_discard(struct dm_thin_new_mapping *m)
+{
+ int r;
+ struct thin_c *tc = m->tc;
+
+ r = dm_thin_remove_block(tc->td, m->virt_block);
+ if (r)
+ DMERR_LIMIT("dm_thin_remove_block() failed");
+
+ process_prepared_discard_passdown(m);
+}
+
+static void process_prepared(struct pool *pool, struct list_head *head,
+ process_mapping_fn *fn)
+{
+ unsigned long flags;
+ struct list_head maps;
+ struct dm_thin_new_mapping *m, *tmp;
+
+ INIT_LIST_HEAD(&maps);
+ spin_lock_irqsave(&pool->lock, flags);
+ list_splice_init(head, &maps);
+ spin_unlock_irqrestore(&pool->lock, flags);
+
+ list_for_each_entry_safe(m, tmp, &maps, list)
+ (*fn)(m);
+}
+
+/*
+ * Deferred bio jobs.
+ */
+static int io_overlaps_block(struct pool *pool, struct bio *bio)
+{
+ return bio->bi_iter.bi_size ==
+ (pool->sectors_per_block << SECTOR_SHIFT);
+}
+
+static int io_overwrites_block(struct pool *pool, struct bio *bio)
+{
+ return (bio_data_dir(bio) == WRITE) &&
+ io_overlaps_block(pool, bio);
+}
+
+static void save_and_set_endio(struct bio *bio, bio_end_io_t **save,
+ bio_end_io_t *fn)
+{
+ *save = bio->bi_end_io;
+ bio->bi_end_io = fn;
+}
+
+static int ensure_next_mapping(struct pool *pool)
+{
+ if (pool->next_mapping)
+ return 0;
+
+ pool->next_mapping = mempool_alloc(pool->mapping_pool, GFP_ATOMIC);
+
+ return pool->next_mapping ? 0 : -ENOMEM;
+}
+
+static struct dm_thin_new_mapping *get_next_mapping(struct pool *pool)
+{
+ struct dm_thin_new_mapping *m = pool->next_mapping;
+
+ BUG_ON(!pool->next_mapping);
+
+ memset(m, 0, sizeof(struct dm_thin_new_mapping));
+ INIT_LIST_HEAD(&m->list);
+ m->bio = NULL;
+
+ pool->next_mapping = NULL;
+
+ return m;
+}
+
+static void ll_zero(struct thin_c *tc, struct dm_thin_new_mapping *m,
+ sector_t begin, sector_t end)
+{
+ int r;
+ struct dm_io_region to;
+
+ to.bdev = tc->pool_dev->bdev;
+ to.sector = begin;
+ to.count = end - begin;
+
+ r = dm_kcopyd_zero(tc->pool->copier, 1, &to, 0, copy_complete, m);
+ if (r < 0) {
+ DMERR_LIMIT("dm_kcopyd_zero() failed");
+ copy_complete(1, 1, m);
+ }
+}
+
+static void remap_and_issue_overwrite(struct thin_c *tc, struct bio *bio,
+ dm_block_t data_block,
+ 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_block);
+}
+
+/*
+ * A partial copy also needs to zero the uncopied region.
+ */
+static void schedule_copy(struct thin_c *tc, dm_block_t virt_block,
+ struct dm_dev *origin, dm_block_t data_origin,
+ dm_block_t data_dest,
+ struct dm_bio_prison_cell *cell, struct bio *bio,
+ sector_t len)
+{
+ int r;
+ struct pool *pool = tc->pool;
+ struct dm_thin_new_mapping *m = get_next_mapping(pool);
+
+ m->tc = tc;
+ m->virt_block = virt_block;
+ m->data_block = data_dest;
+ m->cell = cell;
+
+ /*
+ * quiesce action + copy action + an extra reference held for the
+ * duration of this function (we may need to inc later for a
+ * partial zero).
+ */
+ atomic_set(&m->prepare_actions, 3);
+
+ if (!dm_deferred_set_add_work(pool->shared_read_ds, &m->list))
+ complete_mapping_preparation(m); /* already quiesced */
+
+ /*
+ * IO to pool_dev remaps to the pool target's data_dev.
+ *
+ * If the whole block of data is being overwritten, we can issue the
+ * bio immediately. Otherwise we use kcopyd to clone the data first.
+ */
+ if (io_overwrites_block(pool, bio))
+ remap_and_issue_overwrite(tc, bio, data_dest, m);
+ else {
+ struct dm_io_region from, to;
+
+ from.bdev = origin->bdev;
+ from.sector = data_origin * pool->sectors_per_block;
+ from.count = len;
+
+ to.bdev = tc->pool_dev->bdev;
+ to.sector = data_dest * pool->sectors_per_block;
+ to.count = len;
+
+ r = dm_kcopyd_copy(pool->copier, &from, 1, &to,
+ 0, copy_complete, m);
+ if (r < 0) {
+ DMERR_LIMIT("dm_kcopyd_copy() failed");
+ copy_complete(1, 1, m);
+
+ /*
+ * We allow the zero to be issued, to simplify the
+ * error path. Otherwise we'd need to start
+ * worrying about decrementing the prepare_actions
+ * counter.
+ */
+ }
+
+ /*
+ * Do we need to zero a tail region?
+ */
+ if (len < pool->sectors_per_block && pool->pf.zero_new_blocks) {
+ atomic_inc(&m->prepare_actions);
+ ll_zero(tc, m,
+ data_dest * pool->sectors_per_block + len,
+ (data_dest + 1) * pool->sectors_per_block);
+ }
+ }
+
+ complete_mapping_preparation(m); /* drop our ref */
+}
+
+static void schedule_internal_copy(struct thin_c *tc, dm_block_t virt_block,
+ dm_block_t data_origin, dm_block_t data_dest,
+ struct dm_bio_prison_cell *cell, struct bio *bio)
+{
+ schedule_copy(tc, virt_block, tc->pool_dev,
+ data_origin, data_dest, cell, bio,
+ tc->pool->sectors_per_block);
+}
+
+static void schedule_zero(struct thin_c *tc, dm_block_t virt_block,
+ dm_block_t data_block, struct dm_bio_prison_cell *cell,
+ struct bio *bio)
+{
+ struct pool *pool = tc->pool;
+ struct dm_thin_new_mapping *m = get_next_mapping(pool);
+
+ atomic_set(&m->prepare_actions, 1); /* no need to quiesce */
+ m->tc = tc;
+ m->virt_block = virt_block;
+ 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)
+ process_prepared_mapping(m);
+
+ else 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);
+}
+
+static void schedule_external_copy(struct thin_c *tc, dm_block_t virt_block,
+ dm_block_t data_dest,
+ struct dm_bio_prison_cell *cell, struct bio *bio)
+{
+ struct pool *pool = tc->pool;
+ sector_t virt_block_begin = virt_block * pool->sectors_per_block;
+ sector_t virt_block_end = (virt_block + 1) * pool->sectors_per_block;
+
+ if (virt_block_end <= tc->origin_size)
+ schedule_copy(tc, virt_block, tc->origin_dev,
+ virt_block, data_dest, cell, bio,
+ pool->sectors_per_block);
+
+ else if (virt_block_begin < tc->origin_size)
+ schedule_copy(tc, virt_block, tc->origin_dev,
+ virt_block, data_dest, cell, bio,
+ tc->origin_size - virt_block_begin);
+
+ else
+ schedule_zero(tc, virt_block, data_dest, cell, bio);
+}
+
+static void set_pool_mode(struct pool *pool, enum pool_mode new_mode);
+
+static void check_for_space(struct pool *pool)
+{
+ int r;
+ dm_block_t nr_free;
+
+ if (get_pool_mode(pool) != PM_OUT_OF_DATA_SPACE)
+ return;
+
+ r = dm_pool_get_free_block_count(pool->pmd, &nr_free);
+ if (r)
+ return;
+
+ if (nr_free)
+ set_pool_mode(pool, PM_WRITE);
+}
+
+/*
+ * A non-zero return indicates read_only or fail_io mode.
+ * Many callers don't care about the return value.
+ */
+static int commit(struct pool *pool)
+{
+ int r;
+
+ if (get_pool_mode(pool) >= PM_READ_ONLY)
+ return -EINVAL;
+
+ r = dm_pool_commit_metadata(pool->pmd);
+ if (r)
+ metadata_operation_failed(pool, "dm_pool_commit_metadata", r);
+ else
+ check_for_space(pool);
+
+ return r;
+}
+
+static void check_low_water_mark(struct pool *pool, dm_block_t free_blocks)
+{
+ unsigned long flags;
+
+ if (free_blocks <= pool->low_water_blocks && !pool->low_water_triggered) {
+ DMWARN("%s: reached low water mark for data device: sending event.",
+ dm_device_name(pool->pool_md));
+ spin_lock_irqsave(&pool->lock, flags);
+ pool->low_water_triggered = true;
+ spin_unlock_irqrestore(&pool->lock, flags);
+ dm_table_event(pool->ti->table);
+ }
+}
+
+static int alloc_data_block(struct thin_c *tc, dm_block_t *result)
+{
+ int r;
+ dm_block_t free_blocks;
+ struct pool *pool = tc->pool;
+
+ if (WARN_ON(get_pool_mode(pool) != PM_WRITE))
+ return -EINVAL;
+
+ r = dm_pool_get_free_block_count(pool->pmd, &free_blocks);
+ if (r) {
+ metadata_operation_failed(pool, "dm_pool_get_free_block_count", r);
+ return r;
+ }
+
+ check_low_water_mark(pool, free_blocks);
+
+ if (!free_blocks) {
+ /*
+ * Try to commit to see if that will free up some
+ * more space.
+ */
+ r = commit(pool);
+ if (r)
+ return r;
+
+ r = dm_pool_get_free_block_count(pool->pmd, &free_blocks);
+ if (r) {
+ metadata_operation_failed(pool, "dm_pool_get_free_block_count", r);
+ return r;
+ }
+
+ if (!free_blocks) {
+ set_pool_mode(pool, PM_OUT_OF_DATA_SPACE);
+ return -ENOSPC;
+ }
+ }
+
+ r = dm_pool_alloc_data_block(pool->pmd, result);
+ if (r) {
+ metadata_operation_failed(pool, "dm_pool_alloc_data_block", r);
+ return r;
+ }
+
+ return 0;
+}
+
+/*
+ * If we have run out of space, queue bios until the device is
+ * resumed, presumably after having been reloaded with more space.
+ */
+static void retry_on_resume(struct bio *bio)
+{
+ struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
+ struct thin_c *tc = h->tc;
+ unsigned long flags;
+
+ spin_lock_irqsave(&tc->lock, flags);
+ bio_list_add(&tc->retry_on_resume_list, bio);
+ spin_unlock_irqrestore(&tc->lock, flags);
+}
+
+static int should_error_unserviceable_bio(struct pool *pool)
+{
+ enum pool_mode m = get_pool_mode(pool);
+
+ switch (m) {
+ case PM_WRITE:
+ /* Shouldn't get here */
+ DMERR_LIMIT("bio unserviceable, yet pool is in PM_WRITE mode");
+ return -EIO;
+
+ case PM_OUT_OF_DATA_SPACE:
+ return pool->pf.error_if_no_space ? -ENOSPC : 0;
+
+ case PM_READ_ONLY:
+ case PM_FAIL:
+ return -EIO;
+ default:
+ /* Shouldn't get here */
+ DMERR_LIMIT("bio unserviceable, yet pool has an unknown mode");
+ return -EIO;
+ }
+}
+
+static void handle_unserviceable_bio(struct pool *pool, struct bio *bio)
+{
+ int error = should_error_unserviceable_bio(pool);
+
+ if (error)
+ bio_endio(bio, error);
+ else
+ retry_on_resume(bio);
+}
+
+static void retry_bios_on_resume(struct pool *pool, struct dm_bio_prison_cell *cell)
+{
+ struct bio *bio;
+ struct bio_list bios;
+ int error;
+
+ error = should_error_unserviceable_bio(pool);
+ if (error) {
+ cell_error_with_code(pool, cell, error);
+ return;
+ }
+
+ bio_list_init(&bios);
+ cell_release(pool, cell, &bios);
+
+ while ((bio = bio_list_pop(&bios)))
+ retry_on_resume(bio);
+}
+
+static void process_discard_cell(struct thin_c *tc, struct dm_bio_prison_cell *cell)
+{
+ int r;
+ struct bio *bio = cell->holder;
+ struct pool *pool = tc->pool;
+ struct dm_bio_prison_cell *cell2;
+ struct dm_cell_key key2;
+ dm_block_t block = get_bio_block(tc, bio);
+ struct dm_thin_lookup_result lookup_result;
+ struct dm_thin_new_mapping *m;
+
+ if (tc->requeue_mode) {
+ cell_requeue(pool, cell);
+ return;
+ }
+
+ r = dm_thin_find_block(tc->td, block, 1, &lookup_result);
+ switch (r) {
+ case 0:
+ /*
+ * Check nobody is fiddling with this pool block. This can
+ * happen if someone's in the process of breaking sharing
+ * on this block.
+ */
+ build_data_key(tc->td, lookup_result.block, &key2);
+ if (bio_detain(tc->pool, &key2, bio, &cell2)) {
+ cell_defer_no_holder(tc, cell);
+ break;
+ }
+
+ if (io_overlaps_block(pool, bio)) {
+ /*
+ * IO may still be going to the destination block. We must
+ * quiesce before we can do the removal.
+ */
+ m = get_next_mapping(pool);
+ m->tc = tc;
+ m->pass_discard = pool->pf.discard_passdown;
+ m->definitely_not_shared = !lookup_result.shared;
+ m->virt_block = block;
+ m->data_block = lookup_result.block;
+ m->cell = cell;
+ m->cell2 = cell2;
+ m->bio = bio;
+
+ if (!dm_deferred_set_add_work(pool->all_io_ds, &m->list))
+ pool->process_prepared_discard(m);
+
+ } else {
+ inc_all_io_entry(pool, bio);
+ cell_defer_no_holder(tc, cell);
+ cell_defer_no_holder(tc, cell2);
+
+ /*
+ * The DM core makes sure that the discard doesn't span
+ * a block boundary. So we submit the discard of a
+ * partial block appropriately.
+ */
+ if ((!lookup_result.shared) && pool->pf.discard_passdown)
+ remap_and_issue(tc, bio, lookup_result.block);
+ else
+ bio_endio(bio, 0);
+ }
+ break;
+
+ case -ENODATA:
+ /*
+ * It isn't provisioned, just forget it.
+ */
+ cell_defer_no_holder(tc, cell);
+ bio_endio(bio, 0);
+ 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_discard_bio(struct thin_c *tc, struct bio *bio)
+{
+ struct dm_bio_prison_cell *cell;
+ struct dm_cell_key key;
+ dm_block_t block = get_bio_block(tc, bio);
+
+ build_virtual_key(tc->td, block, &key);
+ if (bio_detain(tc->pool, &key, bio, &cell))
+ return;
+
+ process_discard_cell(tc, 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) ||
+ (bio->bi_rw & (REQ_DISCARD | REQ_FLUSH | REQ_FUA)))
+ 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, 0);
+ return;
+ }
+
+ r = alloc_data_block(tc, &data_block);
+ switch (r) {
+ case 0:
+ if (tc->origin_dev)
+ schedule_external_copy(tc, block, data_block, cell, bio);
+ else
+ schedule_zero(tc, block, data_block, cell, bio);
+ break;
+
+ case -ENOSPC:
+ 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, 0);
+ }
+ } 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, 0);
+ 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, 0);
+}
+
+static void process_bio_fail(struct thin_c *tc, struct bio *bio)
+{
+ bio_io_error(bio);
+}
+
+static void process_cell_success(struct thin_c *tc, struct dm_bio_prison_cell *cell)
+{
+ cell_success(tc->pool, cell);
+}
+
+static void process_cell_fail(struct thin_c *tc, struct dm_bio_prison_cell *cell)
+{
+ cell_error(tc->pool, cell);
+}
+
+/*
+ * FIXME: should we also commit due to size of transaction, measured in
+ * metadata blocks?
+ */
+static int need_commit_due_to_time(struct pool *pool)
+{
+ return !time_in_range(jiffies, pool->last_commit_jiffies,
+ pool->last_commit_jiffies + COMMIT_PERIOD);
+}
+
+#define thin_pbd(node) rb_entry((node), struct dm_thin_endio_hook, rb_node)
+#define thin_bio(pbd) dm_bio_from_per_bio_data((pbd), sizeof(struct dm_thin_endio_hook))
+
+static void __thin_bio_rb_add(struct thin_c *tc, struct bio *bio)
+{
+ struct rb_node **rbp, *parent;
+ struct dm_thin_endio_hook *pbd;
+ sector_t bi_sector = bio->bi_iter.bi_sector;
+
+ rbp = &tc->sort_bio_list.rb_node;
+ parent = NULL;
+ while (*rbp) {
+ parent = *rbp;
+ pbd = thin_pbd(parent);
+
+ if (bi_sector < thin_bio(pbd)->bi_iter.bi_sector)
+ rbp = &(*rbp)->rb_left;
+ else
+ rbp = &(*rbp)->rb_right;
+ }
+
+ pbd = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
+ rb_link_node(&pbd->rb_node, parent, rbp);
+ rb_insert_color(&pbd->rb_node, &tc->sort_bio_list);
+}
+
+static void __extract_sorted_bios(struct thin_c *tc)
+{
+ struct rb_node *node;
+ struct dm_thin_endio_hook *pbd;
+ struct bio *bio;
+
+ for (node = rb_first(&tc->sort_bio_list); node; node = rb_next(node)) {
+ pbd = thin_pbd(node);
+ bio = thin_bio(pbd);
+
+ bio_list_add(&tc->deferred_bio_list, bio);
+ rb_erase(&pbd->rb_node, &tc->sort_bio_list);
+ }
+
+ WARN_ON(!RB_EMPTY_ROOT(&tc->sort_bio_list));
+}
+
+static void __sort_thin_deferred_bios(struct thin_c *tc)
+{
+ struct bio *bio;
+ struct bio_list bios;
+
+ bio_list_init(&bios);
+ bio_list_merge(&bios, &tc->deferred_bio_list);
+ bio_list_init(&tc->deferred_bio_list);
+
+ /* Sort deferred_bio_list using rb-tree */
+ while ((bio = bio_list_pop(&bios)))
+ __thin_bio_rb_add(tc, bio);
+
+ /*
+ * Transfer the sorted bios in sort_bio_list back to
+ * deferred_bio_list to allow lockless submission of
+ * all bios.
+ */
+ __extract_sorted_bios(tc);
+}
+
+static void process_thin_deferred_bios(struct thin_c *tc)
+{
+ struct pool *pool = tc->pool;
+ unsigned long flags;
+ struct bio *bio;
+ struct bio_list bios;
+ struct blk_plug plug;
+ unsigned count = 0;
+
+ if (tc->requeue_mode) {
+ error_thin_bio_list(tc, &tc->deferred_bio_list, DM_ENDIO_REQUEUE);
+ return;
+ }
+
+ bio_list_init(&bios);
+
+ spin_lock_irqsave(&tc->lock, flags);
+
+ if (bio_list_empty(&tc->deferred_bio_list)) {
+ spin_unlock_irqrestore(&tc->lock, flags);
+ return;
+ }
+
+ __sort_thin_deferred_bios(tc);
+
+ bio_list_merge(&bios, &tc->deferred_bio_list);
+ bio_list_init(&tc->deferred_bio_list);
+
+ spin_unlock_irqrestore(&tc->lock, flags);
+
+ blk_start_plug(&plug);
+ while ((bio = bio_list_pop(&bios))) {
+ /*
+ * If we've got no free new_mapping structs, and processing
+ * this bio might require one, we pause until there are some
+ * prepared mappings to process.
+ */
+ if (ensure_next_mapping(pool)) {
+ spin_lock_irqsave(&tc->lock, flags);
+ bio_list_add(&tc->deferred_bio_list, bio);
+ bio_list_merge(&tc->deferred_bio_list, &bios);
+ spin_unlock_irqrestore(&tc->lock, flags);
+ break;
+ }
+
+ if (bio->bi_rw & REQ_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 (cell->holder->bi_rw & REQ_DISCARD)
+ pool->process_discard_cell(tc, cell);
+ else
+ pool->process_cell(tc, cell);
+ }
+ } while (!list_empty(&cells));
+}
+
+static void thin_get(struct thin_c *tc);
+static void thin_put(struct thin_c *tc);
+
+/*
+ * We can't hold rcu_read_lock() around code that can block. So we
+ * find a thin with the rcu lock held; bump a refcount; then drop
+ * the lock.
+ */
+static struct thin_c *get_first_thin(struct pool *pool)
+{
+ struct thin_c *tc = NULL;
+
+ rcu_read_lock();
+ if (!list_empty(&pool->active_thins)) {
+ tc = list_entry_rcu(pool->active_thins.next, struct thin_c, list);
+ thin_get(tc);
+ }
+ rcu_read_unlock();
+
+ return tc;
+}
+
+static struct thin_c *get_next_thin(struct pool *pool, struct thin_c *tc)
+{
+ struct thin_c *old_tc = tc;
+
+ rcu_read_lock();
+ list_for_each_entry_continue_rcu(tc, &pool->active_thins, list) {
+ thin_get(tc);
+ thin_put(old_tc);
+ rcu_read_unlock();
+ return tc;
+ }
+ thin_put(old_tc);
+ rcu_read_unlock();
+
+ return NULL;
+}
+
+static void process_deferred_bios(struct pool *pool)
+{
+ unsigned long flags;
+ struct bio *bio;
+ struct bio_list bios;
+ struct thin_c *tc;
+
+ tc = get_first_thin(pool);
+ while (tc) {
+ process_thin_deferred_cells(tc);
+ process_thin_deferred_bios(tc);
+ tc = get_next_thin(pool, tc);
+ }
+
+ /*
+ * If there are any deferred flush bios, we must commit
+ * the metadata before issuing them.
+ */
+ bio_list_init(&bios);
+ spin_lock_irqsave(&pool->lock, flags);
+ bio_list_merge(&bios, &pool->deferred_flush_bios);
+ bio_list_init(&pool->deferred_flush_bios);
+ spin_unlock_irqrestore(&pool->lock, flags);
+
+ if (bio_list_empty(&bios) &&
+ !(dm_pool_changed_this_transaction(pool->pmd) && need_commit_due_to_time(pool)))
+ return;
+
+ if (commit(pool)) {
+ while ((bio = bio_list_pop(&bios)))
+ bio_io_error(bio);
+ return;
+ }
+ pool->last_commit_jiffies = jiffies;
+
+ while ((bio = bio_list_pop(&bios)))
+ generic_make_request(bio);
+}
+
+static void do_worker(struct work_struct *ws)
+{
+ struct pool *pool = container_of(ws, struct pool, worker);
+
+ throttle_work_start(&pool->throttle);
+ dm_pool_issue_prefetches(pool->pmd);
+ throttle_work_update(&pool->throttle);
+ process_prepared(pool, &pool->prepared_mappings, &pool->process_prepared_mapping);
+ throttle_work_update(&pool->throttle);
+ process_prepared(pool, &pool->prepared_discards, &pool->process_prepared_discard);
+ throttle_work_update(&pool->throttle);
+ process_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_READ_ONLY and start erroring IO.
+ */
+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)
+ set_pool_mode(pool, PM_READ_ONLY);
+}
+
+/*----------------------------------------------------------------*/
+
+struct pool_work {
+ struct work_struct worker;
+ struct completion complete;
+};
+
+static struct pool_work *to_pool_work(struct work_struct *ws)
+{
+ return container_of(ws, struct pool_work, worker);
+}
+
+static void pool_work_complete(struct pool_work *pw)
+{
+ complete(&pw->complete);
+}
+
+static void pool_work_wait(struct pool_work *pw, struct pool *pool,
+ void (*fn)(struct work_struct *))
+{
+ INIT_WORK_ONSTACK(&pw->worker, fn);
+ init_completion(&pw->complete);
+ queue_work(pool->wq, &pw->worker);
+ wait_for_completion(&pw->complete);
+}
+
+/*----------------------------------------------------------------*/
+
+struct noflush_work {
+ struct pool_work pw;
+ struct thin_c *tc;
+};
+
+static struct noflush_work *to_noflush(struct work_struct *ws)
+{
+ return container_of(to_pool_work(ws), struct noflush_work, pw);
+}
+
+static void do_noflush_start(struct work_struct *ws)
+{
+ struct noflush_work *w = to_noflush(ws);
+ w->tc->requeue_mode = true;
+ requeue_io(w->tc);
+ pool_work_complete(&w->pw);
+}
+
+static void do_noflush_stop(struct work_struct *ws)
+{
+ struct noflush_work *w = to_noflush(ws);
+ w->tc->requeue_mode = false;
+ pool_work_complete(&w->pw);
+}
+
+static void noflush_work(struct thin_c *tc, void (*fn)(struct work_struct *))
+{
+ struct noflush_work w;
+
+ w.tc = tc;
+ pool_work_wait(&w.pw, tc->pool, fn);
+}
+
+/*----------------------------------------------------------------*/
+
+static enum pool_mode get_pool_mode(struct pool *pool)
+{
+ return pool->pf.mode;
+}
+
+static void notify_of_pool_mode_change(struct pool *pool, const char *new_mode)
+{
+ dm_table_event(pool->ti->table);
+ DMINFO("%s: switching pool to %s mode",
+ dm_device_name(pool->pool_md), new_mode);
+}
+
+static void set_pool_mode(struct pool *pool, enum pool_mode new_mode)
+{
+ struct pool_c *pt = pool->ti->private;
+ bool needs_check = dm_pool_metadata_needs_check(pool->pmd);
+ enum pool_mode old_mode = get_pool_mode(pool);
+ unsigned long no_space_timeout = ACCESS_ONCE(no_space_timeout_secs) * HZ;
+
+ /*
+ * Never allow the pool to transition to PM_WRITE mode if user
+ * intervention is required to verify metadata and data consistency.
+ */
+ if (new_mode == PM_WRITE && needs_check) {
+ DMERR("%s: unable to switch pool to write mode until repaired.",
+ dm_device_name(pool->pool_md));
+ if (old_mode != new_mode)
+ new_mode = old_mode;
+ else
+ new_mode = PM_READ_ONLY;
+ }
+ /*
+ * If we were in PM_FAIL mode, rollback of metadata failed. We're
+ * not going to recover without a thin_repair. So we never let the
+ * pool move out of the old mode.
+ */
+ if (old_mode == PM_FAIL)
+ new_mode = old_mode;
+
+ switch (new_mode) {
+ case PM_FAIL:
+ if (old_mode != new_mode)
+ notify_of_pool_mode_change(pool, "failure");
+ dm_pool_metadata_read_only(pool->pmd);
+ pool->process_bio = process_bio_fail;
+ pool->process_discard = process_bio_fail;
+ pool->process_cell = process_cell_fail;
+ pool->process_discard_cell = process_cell_fail;
+ pool->process_prepared_mapping = process_prepared_mapping_fail;
+ pool->process_prepared_discard = process_prepared_discard_fail;
+
+ error_retry_list(pool);
+ break;
+
+ case PM_READ_ONLY:
+ if (old_mode != new_mode)
+ notify_of_pool_mode_change(pool, "read-only");
+ dm_pool_metadata_read_only(pool->pmd);
+ pool->process_bio = process_bio_read_only;
+ pool->process_discard = process_bio_success;
+ pool->process_cell = process_cell_read_only;
+ pool->process_discard_cell = process_cell_success;
+ pool->process_prepared_mapping = process_prepared_mapping_fail;
+ pool->process_prepared_discard = process_prepared_discard_passdown;
+
+ error_retry_list(pool);
+ break;
+
+ case PM_OUT_OF_DATA_SPACE:
+ /*
+ * Ideally we'd never hit this state; the low water mark
+ * would trigger userland to extend the pool before we
+ * completely run out of data space. However, many small
+ * IOs to unprovisioned space can consume data space at an
+ * alarming rate. Adjust your low water mark if you're
+ * frequently seeing this mode.
+ */
+ if (old_mode != new_mode)
+ notify_of_pool_mode_change(pool, "out-of-data-space");
+ pool->process_bio = process_bio_read_only;
+ pool->process_discard = process_discard_bio;
+ pool->process_cell = process_cell_read_only;
+ pool->process_discard_cell = process_discard_cell;
+ pool->process_prepared_mapping = process_prepared_mapping;
+ pool->process_prepared_discard = process_prepared_discard;
+
+ if (!pool->pf.error_if_no_space && no_space_timeout)
+ queue_delayed_work(pool->wq, &pool->no_space_timeout, no_space_timeout);
+ break;
+
+ case PM_WRITE:
+ if (old_mode != new_mode)
+ notify_of_pool_mode_change(pool, "write");
+ 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_discard_cell = process_discard_cell;
+ pool->process_prepared_mapping = process_prepared_mapping;
+ pool->process_prepared_discard = process_prepared_discard;
+ break;
+ }
+
+ pool->pf.mode = new_mode;
+ /*
+ * The pool mode may have changed, sync it so bind_control_target()
+ * doesn't cause an unexpected mode transition on resume.
+ */
+ pt->adjusted_pf.mode = new_mode;
+}
+
+static void abort_transaction(struct pool *pool)
+{
+ const char *dev_name = dm_device_name(pool->pool_md);
+
+ DMERR_LIMIT("%s: aborting current metadata transaction", dev_name);
+ if (dm_pool_abort_metadata(pool->pmd)) {
+ DMERR("%s: failed to abort metadata transaction", dev_name);
+ set_pool_mode(pool, PM_FAIL);
+ }
+
+ if (dm_pool_metadata_set_needs_check(pool->pmd)) {
+ DMERR("%s: failed to set 'needs_check' flag in metadata", dev_name);
+ set_pool_mode(pool, PM_FAIL);
+ }
+}
+
+static void metadata_operation_failed(struct pool *pool, const char *op, int r)
+{
+ DMERR_LIMIT("%s: metadata operation '%s' failed: error = %d",
+ dm_device_name(pool->pool_md), op, r);
+
+ abort_transaction(pool);
+ set_pool_mode(pool, PM_READ_ONLY);
+}
+
+/*----------------------------------------------------------------*/
+
+/*
+ * Mapping functions.
+ */
+
+/*
+ * Called only while mapping a thin bio to hand it over to the workqueue.
+ */
+static void thin_defer_bio(struct thin_c *tc, struct bio *bio)
+{
+ unsigned long flags;
+ struct pool *pool = tc->pool;
+
+ spin_lock_irqsave(&tc->lock, flags);
+ bio_list_add(&tc->deferred_bio_list, bio);
+ spin_unlock_irqrestore(&tc->lock, flags);
+
+ wake_worker(pool);
+}
+
+static void thin_defer_bio_with_throttle(struct thin_c *tc, struct bio *bio)
+{
+ struct pool *pool = tc->pool;
+
+ throttle_lock(&pool->throttle);
+ thin_defer_bio(tc, bio);
+ throttle_unlock(&pool->throttle);
+}
+
+static void thin_defer_cell(struct thin_c *tc, struct dm_bio_prison_cell *cell)
+{
+ unsigned long flags;
+ struct pool *pool = tc->pool;
+
+ throttle_lock(&pool->throttle);
+ spin_lock_irqsave(&tc->lock, flags);
+ list_add_tail(&cell->user_list, &tc->deferred_cells);
+ spin_unlock_irqrestore(&tc->lock, flags);
+ throttle_unlock(&pool->throttle);
+
+ wake_worker(pool);
+}
+
+static void thin_hook_bio(struct thin_c *tc, struct bio *bio)
+{
+ struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
+
+ h->tc = tc;
+ h->shared_read_entry = NULL;
+ h->all_io_entry = NULL;
+ h->overwrite_mapping = NULL;
+}
+
+/*
+ * 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_endio(bio, DM_ENDIO_REQUEUE);
+ return DM_MAPIO_SUBMITTED;
+ }
+
+ if (get_pool_mode(tc->pool) == PM_FAIL) {
+ bio_io_error(bio);
+ return DM_MAPIO_SUBMITTED;
+ }
+
+ if (bio->bi_rw & (REQ_DISCARD | REQ_FLUSH | REQ_FUA)) {
+ 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;
+ sector_t block_size = pool->sectors_per_block << SECTOR_SHIFT;
+ 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";
+
+ else if (data_limits->discard_granularity > block_size)
+ reason = "discard granularity larger than a block";
+
+ else if (!is_factor(block_size, data_limits->discard_granularity))
+ reason = "discard granularity not a factor of block size";
+
+ if (reason) {
+ DMWARN("Data device (%s) %s: Disabling discard passdown.", bdevname(data_bdev, buf), reason);
+ pt->adjusted_pf.discard_passdown = false;
+ }
+}
+
+static int bind_control_target(struct pool *pool, struct dm_target *ti)
+{
+ struct pool_c *pt = ti->private;
+
+ /*
+ * We want to make sure that a pool in PM_FAIL mode is never upgraded.
+ */
+ enum pool_mode old_mode = get_pool_mode(pool);
+ enum pool_mode new_mode = pt->adjusted_pf.mode;
+
+ /*
+ * Don't change the pool's mode until set_pool_mode() below.
+ * Otherwise the pool's process_* function pointers may
+ * not match the desired pool mode.
+ */
+ pt->adjusted_pf.mode = old_mode;
+
+ pool->ti = ti;
+ pool->pf = pt->adjusted_pf;
+ pool->low_water_blocks = pt->low_water_blocks;
+
+ set_pool_mode(pool, new_mode);
+
+ return 0;
+}
+
+static void unbind_control_target(struct pool *pool, struct dm_target *ti)
+{
+ if (pool->ti == ti)
+ pool->ti = NULL;
+}
+
+/*----------------------------------------------------------------
+ * Pool creation
+ *--------------------------------------------------------------*/
+/* Initialize pool features. */
+static void pool_features_init(struct pool_features *pf)
+{
+ pf->mode = PM_WRITE;
+ pf->zero_new_blocks = true;
+ pf->discard_enabled = true;
+ pf->discard_passdown = true;
+ pf->error_if_no_space = false;
+}
+
+static void __pool_destroy(struct pool *pool)
+{
+ __pool_table_remove(pool);
+
+ vfree(pool->cell_sort_array);
+ if (dm_pool_metadata_close(pool->pmd) < 0)
+ DMWARN("%s: dm_pool_metadata_close() failed.", __func__);
+
+ dm_bio_prison_destroy(pool->prison);
+ dm_kcopyd_client_destroy(pool->copier);
+
+ if (pool->wq)
+ destroy_workqueue(pool->wq);
+
+ if (pool->next_mapping)
+ mempool_free(pool->next_mapping, pool->mapping_pool);
+ mempool_destroy(pool->mapping_pool);
+ dm_deferred_set_destroy(pool->shared_read_ds);
+ dm_deferred_set_destroy(pool->all_io_ds);
+ kfree(pool);
+}
+
+static struct kmem_cache *_new_mapping_cache;
+
+static struct pool *pool_create(struct mapped_device *pool_md,
+ struct block_device *metadata_dev,
+ unsigned long block_size,
+ int read_only, char **error)
+{
+ int r;
+ void *err_p;
+ struct pool *pool;
+ struct dm_pool_metadata *pmd;
+ bool format_device = read_only ? false : true;
+
+ pmd = dm_pool_metadata_open(metadata_dev, block_size, format_device);
+ if (IS_ERR(pmd)) {
+ *error = "Error creating metadata object";
+ return (struct pool *)pmd;
+ }
+
+ pool = kmalloc(sizeof(*pool), GFP_KERNEL);
+ if (!pool) {
+ *error = "Error allocating memory for pool";
+ err_p = ERR_PTR(-ENOMEM);
+ goto bad_pool;
+ }
+
+ pool->pmd = pmd;
+ pool->sectors_per_block = block_size;
+ if (block_size & (block_size - 1))
+ pool->sectors_per_block_shift = -1;
+ else
+ pool->sectors_per_block_shift = __ffs(block_size);
+ pool->low_water_blocks = 0;
+ pool_features_init(&pool->pf);
+ pool->prison = dm_bio_prison_create();
+ if (!pool->prison) {
+ *error = "Error creating pool's bio prison";
+ err_p = ERR_PTR(-ENOMEM);
+ goto bad_prison;
+ }
+
+ pool->copier = dm_kcopyd_client_create(&dm_kcopyd_throttle);
+ if (IS_ERR(pool->copier)) {
+ r = PTR_ERR(pool->copier);
+ *error = "Error creating pool's kcopyd client";
+ err_p = ERR_PTR(r);
+ goto bad_kcopyd_client;
+ }
+
+ /*
+ * Create singlethreaded workqueue that will service all devices
+ * that use this metadata.
+ */
+ pool->wq = alloc_ordered_workqueue("dm-" DM_MSG_PREFIX, WQ_MEM_RECLAIM);
+ if (!pool->wq) {
+ *error = "Error creating pool's workqueue";
+ err_p = ERR_PTR(-ENOMEM);
+ goto bad_wq;
+ }
+
+ throttle_init(&pool->throttle);
+ INIT_WORK(&pool->worker, do_worker);
+ INIT_DELAYED_WORK(&pool->waker, do_waker);
+ INIT_DELAYED_WORK(&pool->no_space_timeout, do_no_space_timeout);
+ spin_lock_init(&pool->lock);
+ bio_list_init(&pool->deferred_flush_bios);
+ INIT_LIST_HEAD(&pool->prepared_mappings);
+ INIT_LIST_HEAD(&pool->prepared_discards);
+ INIT_LIST_HEAD(&pool->active_thins);
+ pool->low_water_triggered = false;
+ pool->suspended = true;
+
+ pool->shared_read_ds = dm_deferred_set_create();
+ if (!pool->shared_read_ds) {
+ *error = "Error creating pool's shared read deferred set";
+ err_p = ERR_PTR(-ENOMEM);
+ goto bad_shared_read_ds;
+ }
+
+ pool->all_io_ds = dm_deferred_set_create();
+ if (!pool->all_io_ds) {
+ *error = "Error creating pool's all io deferred set";
+ err_p = ERR_PTR(-ENOMEM);
+ goto bad_all_io_ds;
+ }
+
+ pool->next_mapping = NULL;
+ pool->mapping_pool = mempool_create_slab_pool(MAPPING_POOL_SIZE,
+ _new_mapping_cache);
+ if (!pool->mapping_pool) {
+ *error = "Error creating pool's mapping mempool";
+ err_p = ERR_PTR(-ENOMEM);
+ goto bad_mapping_pool;
+ }
+
+ pool->cell_sort_array = vmalloc(sizeof(*pool->cell_sort_array) * CELL_SORT_ARRAY_SIZE);
+ if (!pool->cell_sort_array) {
+ *error = "Error allocating cell sort array";
+ err_p = ERR_PTR(-ENOMEM);
+ goto bad_sort_array;
+ }
+
+ pool->ref_count = 1;
+ pool->last_commit_jiffies = jiffies;
+ pool->pool_md = pool_md;
+ pool->md_dev = metadata_dev;
+ __pool_table_insert(pool);
+
+ return pool;
+
+bad_sort_array:
+ mempool_destroy(pool->mapping_pool);
+bad_mapping_pool:
+ dm_deferred_set_destroy(pool->all_io_ds);
+bad_all_io_ds:
+ dm_deferred_set_destroy(pool->shared_read_ds);
+bad_shared_read_ds:
+ destroy_workqueue(pool->wq);
+bad_wq:
+ dm_kcopyd_client_destroy(pool->copier);
+bad_kcopyd_client:
+ dm_bio_prison_destroy(pool->prison);
+bad_prison:
+ kfree(pool);
+bad_pool:
+ if (dm_pool_metadata_close(pmd))
+ DMWARN("%s: dm_pool_metadata_close() failed.", __func__);
+
+ return err_p;
+}
+
+static void __pool_inc(struct pool *pool)
+{
+ BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
+ pool->ref_count++;
+}
+
+static void __pool_dec(struct pool *pool)
+{
+ BUG_ON(!mutex_is_locked(&dm_thin_pool_table.mutex));
+ BUG_ON(!pool->ref_count);
+ if (!--pool->ref_count)
+ __pool_destroy(pool);
+}
+
+static struct pool *__pool_find(struct mapped_device *pool_md,
+ struct block_device *metadata_dev,
+ unsigned long block_size, int read_only,
+ char **error, int *created)
+{
+ struct pool *pool = __pool_table_lookup_metadata_dev(metadata_dev);
+
+ if (pool) {
+ if (pool->pool_md != pool_md) {
+ *error = "metadata device already in use by a pool";
+ return ERR_PTR(-EBUSY);
+ }
+ __pool_inc(pool);
+
+ } else {
+ pool = __pool_table_lookup(pool_md);
+ if (pool) {
+ if (pool->md_dev != metadata_dev) {
+ *error = "different pool cannot replace a pool";
+ return ERR_PTR(-EINVAL);
+ }
+ __pool_inc(pool);
+
+ } else {
+ pool = pool_create(pool_md, metadata_dev, block_size, read_only, error);
+ *created = 1;
+ }
+ }
+
+ return pool;
+}
+
+/*----------------------------------------------------------------
+ * Pool target methods
+ *--------------------------------------------------------------*/
+static void pool_dtr(struct dm_target *ti)
+{
+ struct pool_c *pt = ti->private;
+
+ mutex_lock(&dm_thin_pool_table.mutex);
+
+ unbind_control_target(pt->pool, ti);
+ __pool_dec(pt->pool);
+ dm_put_device(ti, pt->metadata_dev);
+ dm_put_device(ti, pt->data_dev);
+ kfree(pt);
+
+ mutex_unlock(&dm_thin_pool_table.mutex);
+}
+
+static int parse_pool_features(struct dm_arg_set *as, struct pool_features *pf,
+ struct dm_target *ti)
+{
+ int r;
+ unsigned argc;
+ const char *arg_name;
+
+ static struct dm_arg _args[] = {
+ {0, 4, "Invalid number of pool feature arguments"},
+ };
+
+ /*
+ * No feature arguments supplied.
+ */
+ if (!as->argc)
+ return 0;
+
+ r = dm_read_arg_group(_args, as, &argc, &ti->error);
+ if (r)
+ return -EINVAL;
+
+ while (argc && !r) {
+ arg_name = dm_shift_arg(as);
+ argc--;
+
+ if (!strcasecmp(arg_name, "skip_block_zeroing"))
+ pf->zero_new_blocks = false;
+
+ else if (!strcasecmp(arg_name, "ignore_discard"))
+ pf->discard_enabled = false;
+
+ else if (!strcasecmp(arg_name, "no_discard_passdown"))
+ pf->discard_passdown = false;
+
+ else if (!strcasecmp(arg_name, "read_only"))
+ pf->mode = PM_READ_ONLY;
+
+ else if (!strcasecmp(arg_name, "error_if_no_space"))
+ pf->error_if_no_space = true;
+
+ else {
+ ti->error = "Unrecognised pool feature requested";
+ r = -EINVAL;
+ break;
+ }
+ }
+
+ return r;
+}
+
+static void metadata_low_callback(void *context)
+{
+ struct pool *pool = context;
+
+ DMWARN("%s: reached low water mark for metadata device: sending event.",
+ dm_device_name(pool->pool_md));
+
+ dm_table_event(pool->ti->table);
+}
+
+static sector_t get_dev_size(struct block_device *bdev)
+{
+ return i_size_read(bdev->bd_inode) >> SECTOR_SHIFT;
+}
+
+static void warn_if_metadata_device_too_big(struct block_device *bdev)
+{
+ sector_t metadata_dev_size = get_dev_size(bdev);
+ char buffer[BDEVNAME_SIZE];
+
+ if (metadata_dev_size > THIN_METADATA_MAX_SECTORS_WARNING)
+ DMWARN("Metadata device %s is larger than %u sectors: excess space will not be used.",
+ bdevname(bdev, buffer), THIN_METADATA_MAX_SECTORS);
+}
+
+static sector_t get_metadata_dev_size(struct block_device *bdev)
+{
+ sector_t metadata_dev_size = get_dev_size(bdev);
+
+ if (metadata_dev_size > THIN_METADATA_MAX_SECTORS)
+ metadata_dev_size = THIN_METADATA_MAX_SECTORS;
+
+ return metadata_dev_size;
+}
+
+static dm_block_t get_metadata_dev_size_in_blocks(struct block_device *bdev)
+{
+ sector_t metadata_dev_size = get_metadata_dev_size(bdev);
+
+ sector_div(metadata_dev_size, THIN_METADATA_BLOCK_SIZE);
+
+ return metadata_dev_size;
+}
+
+/*
+ * When a metadata threshold is crossed a dm event is triggered, and
+ * userland should respond by growing the metadata device. We could let
+ * userland set the threshold, like we do with the data threshold, but I'm
+ * not sure they know enough to do this well.
+ */
+static dm_block_t calc_metadata_threshold(struct pool_c *pt)
+{
+ /*
+ * 4M is ample for all ops with the possible exception of thin
+ * device deletion which is harmless if it fails (just retry the
+ * delete after you've grown the device).
+ */
+ dm_block_t quarter = get_metadata_dev_size_in_blocks(pt->metadata_dev->bdev) / 4;
+ return min((dm_block_t)1024ULL /* 4M */, quarter);
+}
+
+/*
+ * thin-pool <metadata dev> <data dev>
+ * <data block size (sectors)>
+ * <low water mark (blocks)>
+ * [<#feature args> [<arg>]*]
+ *
+ * Optional feature arguments are:
+ * skip_block_zeroing: skips the zeroing of newly-provisioned blocks.
+ * ignore_discard: disable discard
+ * no_discard_passdown: don't pass discards down to the data device
+ * read_only: Don't allow any changes to be made to the pool metadata.
+ * error_if_no_space: error IOs, instead of queueing, if no space.
+ */
+static int pool_ctr(struct dm_target *ti, unsigned argc, char **argv)
+{
+ int r, pool_created = 0;
+ struct pool_c *pt;
+ struct pool *pool;
+ struct pool_features pf;
+ struct dm_arg_set as;
+ struct dm_dev *data_dev;
+ unsigned long block_size;
+ dm_block_t low_water_blocks;
+ struct dm_dev *metadata_dev;
+ fmode_t metadata_mode;
+
+ /*
+ * FIXME Remove validation from scope of lock.
+ */
+ mutex_lock(&dm_thin_pool_table.mutex);
+
+ if (argc < 4) {
+ ti->error = "Invalid argument count";
+ r = -EINVAL;
+ goto out_unlock;
+ }
+
+ as.argc = argc;
+ as.argv = argv;
+
+ /*
+ * Set default pool features.
+ */
+ pool_features_init(&pf);
+
+ dm_consume_args(&as, 4);
+ r = parse_pool_features(&as, &pf, ti);
+ if (r)
+ goto out_unlock;
+
+ metadata_mode = FMODE_READ | ((pf.mode == PM_READ_ONLY) ? 0 : FMODE_WRITE);
+ r = dm_get_device(ti, argv[0], metadata_mode, &metadata_dev);
+ if (r) {
+ ti->error = "Error opening metadata block device";
+ goto out_unlock;
+ }
+ warn_if_metadata_device_too_big(metadata_dev->bdev);
+
+ r = dm_get_device(ti, argv[1], FMODE_READ | FMODE_WRITE, &data_dev);
+ if (r) {
+ ti->error = "Error getting data device";
+ goto out_metadata;
+ }
+
+ if (kstrtoul(argv[2], 10, &block_size) || !block_size ||
+ block_size < DATA_DEV_BLOCK_SIZE_MIN_SECTORS ||
+ block_size > DATA_DEV_BLOCK_SIZE_MAX_SECTORS ||
+ block_size & (DATA_DEV_BLOCK_SIZE_MIN_SECTORS - 1)) {
+ ti->error = "Invalid block size";
+ r = -EINVAL;
+ goto out;
+ }
+
+ if (kstrtoull(argv[3], 10, (unsigned long long *)&low_water_blocks)) {
+ ti->error = "Invalid low water mark";
+ r = -EINVAL;
+ goto out;
+ }
+
+ pt = kzalloc(sizeof(*pt), GFP_KERNEL);
+ if (!pt) {
+ r = -ENOMEM;
+ goto out;
+ }
+
+ pool = __pool_find(dm_table_get_md(ti->table), metadata_dev->bdev,
+ block_size, pf.mode == PM_READ_ONLY, &ti->error, &pool_created);
+ if (IS_ERR(pool)) {
+ r = PTR_ERR(pool);
+ goto out_free_pt;
+ }
+
+ /*
+ * 'pool_created' reflects whether this is the first table load.
+ * Top level discard support is not allowed to be changed after
+ * initial load. This would require a pool reload to trigger thin
+ * device changes.
+ */
+ if (!pool_created && pf.discard_enabled != pool->pf.discard_enabled) {
+ ti->error = "Discard support cannot be disabled once enabled";
+ r = -EINVAL;
+ goto out_flags_changed;
+ }
+
+ pt->pool = pool;
+ pt->ti = ti;
+ pt->metadata_dev = metadata_dev;
+ pt->data_dev = data_dev;
+ pt->low_water_blocks = low_water_blocks;
+ pt->adjusted_pf = pt->requested_pf = pf;
+ ti->num_flush_bios = 1;
+
+ /*
+ * Only need to enable discards if the pool should pass
+ * them down to the data device. The thin device's discard
+ * processing will cause mappings to be removed from the btree.
+ */
+ ti->discard_zeroes_data_unsupported = true;
+ if (pf.discard_enabled && pf.discard_passdown) {
+ ti->num_discard_bios = 1;
+
+ /*
+ * Setting 'discards_supported' circumvents the normal
+ * stacking of discard limits (this keeps the pool and
+ * thin devices' discard limits consistent).
+ */
+ ti->discards_supported = true;
+ }
+ ti->private = pt;
+
+ r = dm_pool_register_metadata_threshold(pt->pool->pmd,
+ calc_metadata_threshold(pt),
+ metadata_low_callback,
+ pool);
+ if (r)
+ goto out_free_pt;
+
+ pt->callbacks.congested_fn = pool_is_congested;
+ dm_table_add_target_callbacks(ti->table, &pt->callbacks);
+
+ mutex_unlock(&dm_thin_pool_table.mutex);
+
+ return 0;
+
+out_flags_changed:
+ __pool_dec(pool);
+out_free_pt:
+ kfree(pt);
+out:
+ dm_put_device(ti, data_dev);
+out_metadata:
+ dm_put_device(ti, metadata_dev);
+out_unlock:
+ mutex_unlock(&dm_thin_pool_table.mutex);
+
+ return r;
+}
+
+static int pool_map(struct dm_target *ti, struct bio *bio)
+{
+ int r;
+ struct pool_c *pt = ti->private;
+ struct pool *pool = pt->pool;
+ unsigned long flags;
+
+ /*
+ * As this is a singleton target, ti->begin is always zero.
+ */
+ spin_lock_irqsave(&pool->lock, flags);
+ bio->bi_bdev = pt->data_dev->bdev;
+ r = DM_MAPIO_REMAPPED;
+ spin_unlock_irqrestore(&pool->lock, flags);
+
+ return r;
+}
+
+static int maybe_resize_data_dev(struct dm_target *ti, bool *need_commit)
+{
+ int r;
+ struct pool_c *pt = ti->private;
+ struct pool *pool = pt->pool;
+ sector_t data_size = ti->len;
+ dm_block_t sb_data_size;
+
+ *need_commit = false;
+
+ (void) sector_div(data_size, pool->sectors_per_block);
+
+ r = dm_pool_get_data_dev_size(pool->pmd, &sb_data_size);
+ if (r) {
+ DMERR("%s: failed to retrieve data device size",
+ dm_device_name(pool->pool_md));
+ return r;
+ }
+
+ if (data_size < sb_data_size) {
+ DMERR("%s: pool target (%llu blocks) too small: expected %llu",
+ dm_device_name(pool->pool_md),
+ (unsigned long long)data_size, sb_data_size);
+ return -EINVAL;
+
+ } else if (data_size > sb_data_size) {
+ if (dm_pool_metadata_needs_check(pool->pmd)) {
+ DMERR("%s: unable to grow the data device until repaired.",
+ dm_device_name(pool->pool_md));
+ return 0;
+ }
+
+ if (sb_data_size)
+ DMINFO("%s: growing the data device from %llu to %llu blocks",
+ dm_device_name(pool->pool_md),
+ sb_data_size, (unsigned long long)data_size);
+ r = dm_pool_resize_data_dev(pool->pmd, data_size);
+ if (r) {
+ metadata_operation_failed(pool, "dm_pool_resize_data_dev", r);
+ return r;
+ }
+
+ *need_commit = true;
+ }
+
+ return 0;
+}
+
+static int maybe_resize_metadata_dev(struct dm_target *ti, bool *need_commit)
+{
+ int r;
+ struct pool_c *pt = ti->private;
+ struct pool *pool = pt->pool;
+ dm_block_t metadata_dev_size, sb_metadata_dev_size;
+
+ *need_commit = false;
+
+ metadata_dev_size = get_metadata_dev_size_in_blocks(pool->md_dev);
+
+ r = dm_pool_get_metadata_dev_size(pool->pmd, &sb_metadata_dev_size);
+ if (r) {
+ DMERR("%s: failed to retrieve metadata device size",
+ dm_device_name(pool->pool_md));
+ return r;
+ }
+
+ if (metadata_dev_size < sb_metadata_dev_size) {
+ DMERR("%s: metadata device (%llu blocks) too small: expected %llu",
+ dm_device_name(pool->pool_md),
+ metadata_dev_size, sb_metadata_dev_size);
+ return -EINVAL;
+
+ } else if (metadata_dev_size > sb_metadata_dev_size) {
+ if (dm_pool_metadata_needs_check(pool->pmd)) {
+ DMERR("%s: unable to grow the metadata device until repaired.",
+ dm_device_name(pool->pool_md));
+ return 0;
+ }
+
+ warn_if_metadata_device_too_big(pool->md_dev);
+ DMINFO("%s: growing the metadata device from %llu to %llu blocks",
+ dm_device_name(pool->pool_md),
+ sb_metadata_dev_size, metadata_dev_size);
+ r = dm_pool_resize_metadata_dev(pool->pmd, metadata_dev_size);
+ if (r) {
+ metadata_operation_failed(pool, "dm_pool_resize_metadata_dev", r);
+ return r;
+ }
+
+ *need_commit = true;
+ }
+
+ return 0;
+}
+
+/*
+ * Retrieves the number of blocks of the data device from
+ * the superblock and compares it to the actual device size,
+ * thus resizing the data device in case it has grown.
+ *
+ * This both copes with opening preallocated data devices in the ctr
+ * being followed by a resume
+ * -and-
+ * calling the resume method individually after userspace has
+ * grown the data device in reaction to a table event.
+ */
+static int pool_preresume(struct dm_target *ti)
+{
+ int r;
+ bool need_commit1, need_commit2;
+ struct pool_c *pt = ti->private;
+ struct pool *pool = pt->pool;
+
+ /*
+ * Take control of the pool object.
+ */
+ r = bind_control_target(pool, ti);
+ if (r)
+ return r;
+
+ r = maybe_resize_data_dev(ti, &need_commit1);
+ if (r)
+ return r;
+
+ r = maybe_resize_metadata_dev(ti, &need_commit2);
+ if (r)
+ return r;
+
+ if (need_commit1 || need_commit2)
+ (void) commit(pool);
+
+ return 0;
+}
+
+static void pool_suspend_active_thins(struct pool *pool)
+{
+ struct thin_c *tc;
+
+ /* Suspend all active thin devices */
+ tc = get_first_thin(pool);
+ while (tc) {
+ dm_internal_suspend_noflush(tc->thin_md);
+ tc = get_next_thin(pool, tc);
+ }
+}
+
+static void pool_resume_active_thins(struct pool *pool)
+{
+ struct thin_c *tc;
+
+ /* Resume all active thin devices */
+ tc = get_first_thin(pool);
+ while (tc) {
+ dm_internal_resume(tc->thin_md);
+ tc = get_next_thin(pool, tc);
+ }
+}
+
+static void pool_resume(struct dm_target *ti)
+{
+ struct pool_c *pt = ti->private;
+ struct pool *pool = pt->pool;
+ unsigned long flags;
+
+ /*
+ * Must requeue active_thins' bios and then resume
+ * active_thins _before_ clearing 'suspend' flag.
+ */
+ requeue_bios(pool);
+ pool_resume_active_thins(pool);
+
+ spin_lock_irqsave(&pool->lock, flags);
+ pool->low_water_triggered = false;
+ pool->suspended = false;
+ spin_unlock_irqrestore(&pool->lock, flags);
+
+ do_waker(&pool->waker.work);
+}
+
+static void pool_presuspend(struct dm_target *ti)
+{
+ struct pool_c *pt = ti->private;
+ struct pool *pool = pt->pool;
+ unsigned long flags;
+
+ spin_lock_irqsave(&pool->lock, flags);
+ pool->suspended = true;
+ spin_unlock_irqrestore(&pool->lock, flags);
+
+ pool_suspend_active_thins(pool);
+}
+
+static void pool_presuspend_undo(struct dm_target *ti)
+{
+ struct pool_c *pt = ti->private;
+ struct pool *pool = pt->pool;
+ unsigned long flags;
+
+ pool_resume_active_thins(pool);
+
+ spin_lock_irqsave(&pool->lock, flags);
+ pool->suspended = false;
+ spin_unlock_irqrestore(&pool->lock, flags);
+}
+
+static void pool_postsuspend(struct dm_target *ti)
+{
+ struct pool_c *pt = ti->private;
+ struct pool *pool = pt->pool;
+
+ cancel_delayed_work(&pool->waker);
+ cancel_delayed_work(&pool->no_space_timeout);
+ flush_workqueue(pool->wq);
+ (void) commit(pool);
+}
+
+static int check_arg_count(unsigned argc, unsigned args_required)
+{
+ if (argc != args_required) {
+ DMWARN("Message received with %u arguments instead of %u.",
+ argc, args_required);
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+static int read_dev_id(char *arg, dm_thin_id *dev_id, int warning)
+{
+ if (!kstrtoull(arg, 10, (unsigned long long *)dev_id) &&
+ *dev_id <= MAX_DEV_ID)
+ return 0;
+
+ if (warning)
+ DMWARN("Message received with invalid device id: %s", arg);
+
+ return -EINVAL;
+}
+
+static int process_create_thin_mesg(unsigned argc, char **argv, struct pool *pool)
+{
+ dm_thin_id dev_id;
+ int r;
+
+ r = check_arg_count(argc, 2);
+ if (r)
+ return r;
+
+ r = read_dev_id(argv[1], &dev_id, 1);
+ if (r)
+ return r;
+
+ r = dm_pool_create_thin(pool->pmd, dev_id);
+ if (r) {
+ DMWARN("Creation of new thinly-provisioned device with id %s failed.",
+ argv[1]);
+ return r;
+ }
+
+ return 0;
+}
+
+static int process_create_snap_mesg(unsigned argc, char **argv, struct pool *pool)
+{
+ dm_thin_id dev_id;
+ dm_thin_id origin_dev_id;
+ int r;
+
+ r = check_arg_count(argc, 3);
+ if (r)
+ return r;
+
+ r = read_dev_id(argv[1], &dev_id, 1);
+ if (r)
+ return r;
+
+ r = read_dev_id(argv[2], &origin_dev_id, 1);
+ if (r)
+ return r;
+
+ r = dm_pool_create_snap(pool->pmd, dev_id, origin_dev_id);
+ if (r) {
+ DMWARN("Creation of new snapshot %s of device %s failed.",
+ argv[1], argv[2]);
+ return r;
+ }
+
+ return 0;
+}
+
+static int process_delete_mesg(unsigned argc, char **argv, struct pool *pool)
+{
+ dm_thin_id dev_id;
+ int r;
+
+ r = check_arg_count(argc, 2);
+ if (r)
+ return r;
+
+ r = read_dev_id(argv[1], &dev_id, 1);
+ if (r)
+ return r;
+
+ r = dm_pool_delete_thin_device(pool->pmd, dev_id);
+ if (r)
+ DMWARN("Deletion of thin device %s failed.", argv[1]);
+
+ return r;
+}
+
+static int process_set_transaction_id_mesg(unsigned argc, char **argv, struct pool *pool)
+{
+ dm_thin_id old_id, new_id;
+ int r;
+
+ r = check_arg_count(argc, 3);
+ if (r)
+ return r;
+
+ if (kstrtoull(argv[1], 10, (unsigned long long *)&old_id)) {
+ DMWARN("set_transaction_id message: Unrecognised id %s.", argv[1]);
+ return -EINVAL;
+ }
+
+ if (kstrtoull(argv[2], 10, (unsigned long long *)&new_id)) {
+ DMWARN("set_transaction_id message: Unrecognised new id %s.", argv[2]);
+ return -EINVAL;
+ }
+
+ r = dm_pool_set_metadata_transaction_id(pool->pmd, old_id, new_id);
+ if (r) {
+ DMWARN("Failed to change transaction id from %s to %s.",
+ argv[1], argv[2]);
+ return r;
+ }
+
+ return 0;
+}
+
+static int process_reserve_metadata_snap_mesg(unsigned argc, char **argv, struct pool *pool)
+{
+ int r;
+
+ r = check_arg_count(argc, 1);
+ if (r)
+ return r;
+
+ (void) commit(pool);
+
+ r = dm_pool_reserve_metadata_snap(pool->pmd);
+ if (r)
+ DMWARN("reserve_metadata_snap message failed.");
+
+ return r;
+}
+
+static int process_release_metadata_snap_mesg(unsigned argc, char **argv, struct pool *pool)
+{
+ int r;
+
+ r = check_arg_count(argc, 1);
+ if (r)
+ return r;
+
+ r = dm_pool_release_metadata_snap(pool->pmd);
+ if (r)
+ DMWARN("release_metadata_snap message failed.");
+
+ return r;
+}
+
+/*
+ * Messages supported:
+ * create_thin <dev_id>
+ * create_snap <dev_id> <origin_id>
+ * delete <dev_id>
+ * set_transaction_id <current_trans_id> <new_trans_id>
+ * reserve_metadata_snap
+ * release_metadata_snap
+ */
+static int pool_message(struct dm_target *ti, unsigned argc, char **argv)
+{
+ int r = -EINVAL;
+ struct pool_c *pt = ti->private;
+ struct pool *pool = pt->pool;
+
+ if (get_pool_mode(pool) >= PM_READ_ONLY) {
+ DMERR("%s: unable to service pool target messages in READ_ONLY or FAIL mode",
+ dm_device_name(pool->pool_md));
+ return -EINVAL;
+ }
+
+ 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>
+ */
+static void pool_status(struct dm_target *ti, status_type_t type,
+ unsigned status_flags, char *result, unsigned maxlen)
+{
+ int r;
+ unsigned sz = 0;
+ uint64_t transaction_id;
+ dm_block_t nr_free_blocks_data;
+ dm_block_t nr_free_blocks_metadata;
+ dm_block_t nr_blocks_data;
+ dm_block_t nr_blocks_metadata;
+ dm_block_t held_root;
+ char buf[BDEVNAME_SIZE];
+ char buf2[BDEVNAME_SIZE];
+ struct pool_c *pt = ti->private;
+ struct pool *pool = pt->pool;
+
+ switch (type) {
+ case STATUSTYPE_INFO:
+ if (get_pool_mode(pool) == PM_FAIL) {
+ DMEMIT("Fail");
+ break;
+ }
+
+ /* Commit to ensure statistics aren't out-of-date */
+ if (!(status_flags & DM_STATUS_NOFLUSH_FLAG) && !dm_suspended(ti))
+ (void) commit(pool);
+
+ r = dm_pool_get_metadata_transaction_id(pool->pmd, &transaction_id);
+ if (r) {
+ DMERR("%s: dm_pool_get_metadata_transaction_id returned %d",
+ dm_device_name(pool->pool_md), r);
+ goto err;
+ }
+
+ r = dm_pool_get_free_metadata_block_count(pool->pmd, &nr_free_blocks_metadata);
+ if (r) {
+ DMERR("%s: dm_pool_get_free_metadata_block_count returned %d",
+ dm_device_name(pool->pool_md), r);
+ goto err;
+ }
+
+ r = dm_pool_get_metadata_dev_size(pool->pmd, &nr_blocks_metadata);
+ if (r) {
+ DMERR("%s: dm_pool_get_metadata_dev_size returned %d",
+ dm_device_name(pool->pool_md), r);
+ goto err;
+ }
+
+ r = dm_pool_get_free_block_count(pool->pmd, &nr_free_blocks_data);
+ if (r) {
+ DMERR("%s: dm_pool_get_free_block_count returned %d",
+ dm_device_name(pool->pool_md), r);
+ goto err;
+ }
+
+ r = dm_pool_get_data_dev_size(pool->pmd, &nr_blocks_data);
+ if (r) {
+ DMERR("%s: dm_pool_get_data_dev_size returned %d",
+ dm_device_name(pool->pool_md), r);
+ goto err;
+ }
+
+ r = dm_pool_get_metadata_snap(pool->pmd, &held_root);
+ if (r) {
+ DMERR("%s: dm_pool_get_metadata_snap returned %d",
+ dm_device_name(pool->pool_md), r);
+ goto err;
+ }
+
+ DMEMIT("%llu %llu/%llu %llu/%llu ",
+ (unsigned long long)transaction_id,
+ (unsigned long long)(nr_blocks_metadata - nr_free_blocks_metadata),
+ (unsigned long long)nr_blocks_metadata,
+ (unsigned long long)(nr_blocks_data - nr_free_blocks_data),
+ (unsigned long long)nr_blocks_data);
+
+ if (held_root)
+ DMEMIT("%llu ", held_root);
+ else
+ DMEMIT("- ");
+
+ if (pool->pf.mode == PM_OUT_OF_DATA_SPACE)
+ DMEMIT("out_of_data_space ");
+ else if (pool->pf.mode == PM_READ_ONLY)
+ DMEMIT("ro ");
+ else
+ DMEMIT("rw ");
+
+ if (!pool->pf.discard_enabled)
+ DMEMIT("ignore_discard ");
+ else if (pool->pf.discard_passdown)
+ DMEMIT("discard_passdown ");
+ else
+ DMEMIT("no_discard_passdown ");
+
+ if (pool->pf.error_if_no_space)
+ DMEMIT("error_if_no_space ");
+ else
+ DMEMIT("queue_if_no_space ");
+
+ 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 int pool_merge(struct dm_target *ti, struct bvec_merge_data *bvm,
+ struct bio_vec *biovec, int max_size)
+{
+ struct pool_c *pt = ti->private;
+ struct request_queue *q = bdev_get_queue(pt->data_dev->bdev);
+
+ if (!q->merge_bvec_fn)
+ return max_size;
+
+ bvm->bi_bdev = pt->data_dev->bdev;
+
+ return min(max_size, q->merge_bvec_fn(q, bvm, biovec));
+}
+
+static void set_discard_limits(struct pool_c *pt, struct queue_limits *limits)
+{
+ struct pool *pool = pt->pool;
+ struct queue_limits *data_limits;
+
+ limits->max_discard_sectors = pool->sectors_per_block;
+
+ /*
+ * discard_granularity is just a hint, and not enforced.
+ */
+ if (pt->adjusted_pf.discard_passdown) {
+ data_limits = &bdev_get_queue(pt->data_dev->bdev)->limits;
+ limits->discard_granularity = max(data_limits->discard_granularity,
+ pool->sectors_per_block << SECTOR_SHIFT);
+ } else
+ limits->discard_granularity = pool->sectors_per_block << SECTOR_SHIFT;
+}
+
+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);
+
+ set_discard_limits(pt, limits);
+}
+
+static struct target_type pool_target = {
+ .name = "thin-pool",
+ .features = DM_TARGET_SINGLETON | DM_TARGET_ALWAYS_WRITEABLE |
+ DM_TARGET_IMMUTABLE,
+ .version = {1, 14, 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,
+ .merge = pool_merge,
+ .iterate_devices = pool_iterate_devices,
+ .io_hints = pool_io_hints,
+};
+
+/*----------------------------------------------------------------
+ * Thin target methods
+ *--------------------------------------------------------------*/
+static void thin_get(struct thin_c *tc)
+{
+ atomic_inc(&tc->refcount);
+}
+
+static void thin_put(struct thin_c *tc)
+{
+ if (atomic_dec_and_test(&tc->refcount))
+ complete(&tc->can_destroy);
+}
+
+static void thin_dtr(struct dm_target *ti)
+{
+ struct thin_c *tc = ti->private;
+ unsigned long flags;
+
+ spin_lock_irqsave(&tc->pool->lock, flags);
+ list_del_rcu(&tc->list);
+ spin_unlock_irqrestore(&tc->pool->lock, flags);
+ synchronize_rcu();
+
+ thin_put(tc);
+ wait_for_completion(&tc->can_destroy);
+
+ mutex_lock(&dm_thin_pool_table.mutex);
+
+ __pool_dec(tc->pool);
+ dm_pool_close_thin_device(tc->td);
+ dm_put_device(ti, tc->pool_dev);
+ if (tc->origin_dev)
+ dm_put_device(ti, tc->origin_dev);
+ kfree(tc);
+
+ mutex_unlock(&dm_thin_pool_table.mutex);
+}
+
+/*
+ * Thin target parameters:
+ *
+ * <pool_dev> <dev_id> [origin_dev]
+ *
+ * pool_dev: the path to the pool (eg, /dev/mapper/my_pool)
+ * dev_id: the internal device identifier
+ * origin_dev: a device external to the pool that should act as the origin
+ *
+ * If the pool device has discards disabled, they get disabled for the thin
+ * device as well.
+ */
+static int thin_ctr(struct dm_target *ti, unsigned argc, char **argv)
+{
+ int r;
+ struct thin_c *tc;
+ struct dm_dev *pool_dev, *origin_dev;
+ struct mapped_device *pool_md;
+ unsigned long flags;
+
+ mutex_lock(&dm_thin_pool_table.mutex);
+
+ if (argc != 2 && argc != 3) {
+ ti->error = "Invalid argument count";
+ r = -EINVAL;
+ goto out_unlock;
+ }
+
+ tc = ti->private = kzalloc(sizeof(*tc), GFP_KERNEL);
+ if (!tc) {
+ ti->error = "Out of memory";
+ r = -ENOMEM;
+ goto out_unlock;
+ }
+ tc->thin_md = dm_table_get_md(ti->table);
+ spin_lock_init(&tc->lock);
+ INIT_LIST_HEAD(&tc->deferred_cells);
+ bio_list_init(&tc->deferred_bio_list);
+ bio_list_init(&tc->retry_on_resume_list);
+ tc->sort_bio_list = RB_ROOT;
+
+ if (argc == 3) {
+ r = dm_get_device(ti, argv[2], FMODE_READ, &origin_dev);
+ if (r) {
+ ti->error = "Error opening origin device";
+ goto bad_origin_dev;
+ }
+ tc->origin_dev = origin_dev;
+ }
+
+ r = dm_get_device(ti, argv[0], dm_table_get_mode(ti->table), &pool_dev);
+ if (r) {
+ ti->error = "Error opening pool device";
+ goto bad_pool_dev;
+ }
+ tc->pool_dev = pool_dev;
+
+ if (read_dev_id(argv[1], (unsigned long long *)&tc->dev_id, 0)) {
+ ti->error = "Invalid device id";
+ r = -EINVAL;
+ goto bad_common;
+ }
+
+ pool_md = dm_get_md(tc->pool_dev->bdev->bd_dev);
+ if (!pool_md) {
+ ti->error = "Couldn't get pool mapped device";
+ r = -EINVAL;
+ goto bad_common;
+ }
+
+ tc->pool = __pool_table_lookup(pool_md);
+ if (!tc->pool) {
+ ti->error = "Couldn't find pool object";
+ r = -EINVAL;
+ goto bad_pool_lookup;
+ }
+ __pool_inc(tc->pool);
+
+ if (get_pool_mode(tc->pool) == PM_FAIL) {
+ ti->error = "Couldn't open thin device, Pool is in fail mode";
+ r = -EINVAL;
+ goto bad_pool;
+ }
+
+ r = dm_pool_open_thin_device(tc->pool->pmd, tc->dev_id, &tc->td);
+ if (r) {
+ ti->error = "Couldn't open thin internal device";
+ goto bad_pool;
+ }
+
+ r = dm_set_target_max_io_len(ti, tc->pool->sectors_per_block);
+ if (r)
+ goto bad;
+
+ ti->num_flush_bios = 1;
+ ti->flush_supported = true;
+ ti->per_bio_data_size = sizeof(struct dm_thin_endio_hook);
+
+ /* In case the pool supports discards, pass them on. */
+ ti->discard_zeroes_data_unsupported = true;
+ if (tc->pool->pf.discard_enabled) {
+ ti->discards_supported = true;
+ ti->num_discard_bios = 1;
+ /* Discard bios must be split on a block boundary */
+ ti->split_discard_bios = true;
+ }
+
+ mutex_unlock(&dm_thin_pool_table.mutex);
+
+ spin_lock_irqsave(&tc->pool->lock, flags);
+ if (tc->pool->suspended) {
+ spin_unlock_irqrestore(&tc->pool->lock, flags);
+ mutex_lock(&dm_thin_pool_table.mutex); /* reacquire for __pool_dec */
+ ti->error = "Unable to activate thin device while pool is suspended";
+ r = -EINVAL;
+ goto bad;
+ }
+ atomic_set(&tc->refcount, 1);
+ init_completion(&tc->can_destroy);
+ list_add_tail_rcu(&tc->list, &tc->pool->active_thins);
+ spin_unlock_irqrestore(&tc->pool->lock, flags);
+ /*
+ * This synchronize_rcu() call is needed here otherwise we risk a
+ * wake_worker() call finding no bios to process (because the newly
+ * added tc isn't yet visible). So this reduces latency since we
+ * aren't then dependent on the periodic commit to wake_worker().
+ */
+ synchronize_rcu();
+
+ dm_put(pool_md);
+
+ return 0;
+
+bad:
+ dm_pool_close_thin_device(tc->td);
+bad_pool:
+ __pool_dec(tc->pool);
+bad_pool_lookup:
+ dm_put(pool_md);
+bad_common:
+ dm_put_device(ti, tc->pool_dev);
+bad_pool_dev:
+ if (tc->origin_dev)
+ dm_put_device(ti, tc->origin_dev);
+bad_origin_dev:
+ kfree(tc);
+out_unlock:
+ mutex_unlock(&dm_thin_pool_table.mutex);
+
+ return r;
+}
+
+static int thin_map(struct dm_target *ti, struct bio *bio)
+{
+ bio->bi_iter.bi_sector = dm_target_offset(ti, bio->bi_iter.bi_sector);
+
+ return thin_bio_map(ti, bio);
+}
+
+static int thin_endio(struct dm_target *ti, struct bio *bio, int err)
+{
+ unsigned long flags;
+ struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
+ struct list_head work;
+ struct dm_thin_new_mapping *m, *tmp;
+ struct pool *pool = h->tc->pool;
+
+ if (h->shared_read_entry) {
+ INIT_LIST_HEAD(&work);
+ dm_deferred_entry_dec(h->shared_read_entry, &work);
+
+ spin_lock_irqsave(&pool->lock, flags);
+ list_for_each_entry_safe(m, tmp, &work, list) {
+ list_del(&m->list);
+ __complete_mapping_preparation(m);
+ }
+ spin_unlock_irqrestore(&pool->lock, flags);
+ }
+
+ if (h->all_io_entry) {
+ INIT_LIST_HEAD(&work);
+ dm_deferred_entry_dec(h->all_io_entry, &work);
+ if (!list_empty(&work)) {
+ spin_lock_irqsave(&pool->lock, flags);
+ list_for_each_entry_safe(m, tmp, &work, list)
+ list_add_tail(&m->list, &pool->prepared_discards);
+ spin_unlock_irqrestore(&pool->lock, flags);
+ wake_worker(pool);
+ }
+ }
+
+ return 0;
+}
+
+static void thin_presuspend(struct dm_target *ti)
+{
+ struct thin_c *tc = ti->private;
+
+ if (dm_noflush_suspending(ti))
+ noflush_work(tc, do_noflush_start);
+}
+
+static void thin_postsuspend(struct dm_target *ti)
+{
+ struct thin_c *tc = ti->private;
+
+ /*
+ * The dm_noflush_suspending flag has been cleared by now, so
+ * unfortunately we must always run this.
+ */
+ noflush_work(tc, do_noflush_stop);
+}
+
+static int thin_preresume(struct dm_target *ti)
+{
+ struct thin_c *tc = ti->private;
+
+ if (tc->origin_dev)
+ tc->origin_size = get_dev_size(tc->origin_dev->bdev);
+
+ return 0;
+}
+
+/*
+ * <nr mapped sectors> <highest mapped sector>
+ */
+static void thin_status(struct dm_target *ti, status_type_t type,
+ unsigned status_flags, char *result, unsigned maxlen)
+{
+ int r;
+ ssize_t sz = 0;
+ dm_block_t mapped, highest;
+ char buf[BDEVNAME_SIZE];
+ struct thin_c *tc = ti->private;
+
+ if (get_pool_mode(tc->pool) == PM_FAIL) {
+ DMEMIT("Fail");
+ return;
+ }
+
+ if (!tc->td)
+ DMEMIT("-");
+ else {
+ switch (type) {
+ case STATUSTYPE_INFO:
+ r = dm_thin_get_mapped_count(tc->td, &mapped);
+ if (r) {
+ DMERR("dm_thin_get_mapped_count returned %d", r);
+ goto err;
+ }
+
+ r = dm_thin_get_highest_mapped_block(tc->td, &highest);
+ if (r < 0) {
+ DMERR("dm_thin_get_highest_mapped_block returned %d", r);
+ goto err;
+ }
+
+ DMEMIT("%llu ", mapped * tc->pool->sectors_per_block);
+ if (r)
+ DMEMIT("%llu", ((highest + 1) *
+ tc->pool->sectors_per_block) - 1);
+ else
+ DMEMIT("-");
+ break;
+
+ case STATUSTYPE_TABLE:
+ DMEMIT("%s %lu",
+ format_dev_t(buf, tc->pool_dev->bdev->bd_dev),
+ (unsigned long) tc->dev_id);
+ if (tc->origin_dev)
+ DMEMIT(" %s", format_dev_t(buf, tc->origin_dev->bdev->bd_dev));
+ break;
+ }
+ }
+
+ return;
+
+err:
+ DMEMIT("Error");
+}
+
+static int thin_merge(struct dm_target *ti, struct bvec_merge_data *bvm,
+ struct bio_vec *biovec, int max_size)
+{
+ struct thin_c *tc = ti->private;
+ struct request_queue *q = bdev_get_queue(tc->pool_dev->bdev);
+
+ if (!q->merge_bvec_fn)
+ return max_size;
+
+ bvm->bi_bdev = tc->pool_dev->bdev;
+ bvm->bi_sector = dm_target_offset(ti, bvm->bi_sector);
+
+ return min(max_size, q->merge_bvec_fn(q, bvm, biovec));
+}
+
+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 struct target_type thin_target = {
+ .name = "thin",
+ .version = {1, 14, 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,
+ .merge = thin_merge,
+ .iterate_devices = thin_iterate_devices,
+};
+
+/*----------------------------------------------------------------*/
+
+static int __init dm_thin_init(void)
+{
+ int r;
+
+ pool_table_init();
+
+ r = dm_register_target(&thin_target);
+ if (r)
+ return r;
+
+ r = dm_register_target(&pool_target);
+ if (r)
+ goto bad_pool_target;
+
+ r = -ENOMEM;
+
+ _new_mapping_cache = KMEM_CACHE(dm_thin_new_mapping, 0);
+ if (!_new_mapping_cache)
+ goto bad_new_mapping_cache;
+
+ return 0;
+
+bad_new_mapping_cache:
+ dm_unregister_target(&pool_target);
+bad_pool_target:
+ dm_unregister_target(&thin_target);
+
+ return r;
+}
+
+static void dm_thin_exit(void)
+{
+ dm_unregister_target(&thin_target);
+ dm_unregister_target(&pool_target);
+
+ kmem_cache_destroy(_new_mapping_cache);
+}
+
+module_init(dm_thin_init);
+module_exit(dm_thin_exit);
+
+module_param_named(no_space_timeout, no_space_timeout_secs, uint, S_IRUGO | S_IWUSR);
+MODULE_PARM_DESC(no_space_timeout, "Out of data space queue IO timeout in seconds");
+
+MODULE_DESCRIPTION(DM_NAME " thin provisioning target");
+MODULE_AUTHOR("Joe Thornber <dm-devel@redhat.com>");
+MODULE_LICENSE("GPL");
generated by cgit v1.2.3-54-g00ecf (git 2.45.2) at 2024-11-16 15:23:37 +0000