Release 4.14 drivers/md/dm-cache-target.c

Directory: drivers/md
/*
 * Copyright (C) 2012 Red Hat. All rights reserved.
 *
 * This file is released under the GPL.
 */

#include "dm.h"
#include "dm-bio-prison-v2.h"
#include "dm-bio-record.h"
#include "dm-cache-metadata.h"

#include <linux/dm-io.h>
#include <linux/dm-kcopyd.h>
#include <linux/jiffies.h>
#include <linux/init.h>
#include <linux/mempool.h>
#include <linux/module.h>
#include <linux/rwsem.h>
#include <linux/slab.h>
#include <linux/vmalloc.h>


#define DM_MSG_PREFIX "cache"

DECLARE_DM_KCOPYD_THROTTLE_WITH_MODULE_PARM(cache_copy_throttle,
	"A percentage of time allocated for copying to and/or from cache");

/*----------------------------------------------------------------*/

/*
 * Glossary:
 *
 * oblock: index of an origin block
 * cblock: index of a cache block
 * promotion: movement of a block from origin to cache
 * demotion: movement of a block from cache to origin
 * migration: movement of a block between the origin and cache device,
 *            either direction
 */

/*----------------------------------------------------------------*/


struct io_tracker {
	
spinlock_t lock;

	/*
         * Sectors of in-flight IO.
         */
	
sector_t in_flight;

	/*
         * The time, in jiffies, when this device became idle (if it is
         * indeed idle).
         */
	
unsigned long idle_time;
	
unsigned long last_update_time;
};



static void iot_init(struct io_tracker *iot)
{
	spin_lock_init(&iot->lock);
	iot->in_flight = 0ul;
	iot->idle_time = 0ul;
	iot->last_update_time = jiffies;
}

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static bool __iot_idle_for(struct io_tracker *iot, unsigned long jifs)
{
	if (iot->in_flight)
		return false;

	return time_after(jiffies, iot->idle_time + jifs);
}

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static bool iot_idle_for(struct io_tracker *iot, unsigned long jifs)
{
	bool r;
	unsigned long flags;

	spin_lock_irqsave(&iot->lock, flags);
	r = __iot_idle_for(iot, jifs);
	spin_unlock_irqrestore(&iot->lock, flags);

	return r;
}

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static void iot_io_begin(struct io_tracker *iot, sector_t len)
{
	unsigned long flags;

	spin_lock_irqsave(&iot->lock, flags);
	iot->in_flight += len;
	spin_unlock_irqrestore(&iot->lock, flags);
}

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static void __iot_io_end(struct io_tracker *iot, sector_t len)
{
	if (!len)
		return;

	iot->in_flight -= len;
	if (!iot->in_flight)
		iot->idle_time = jiffies;
}

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static void iot_io_end(struct io_tracker *iot, sector_t len)
{
	unsigned long flags;

	spin_lock_irqsave(&iot->lock, flags);
	__iot_io_end(iot, len);
	spin_unlock_irqrestore(&iot->lock, flags);
}

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/*----------------------------------------------------------------*/

/*
 * Represents a chunk of future work.  'input' allows continuations to pass
 * values between themselves, typically error values.
 */

struct continuation {
	
struct work_struct ws;
	
blk_status_t input;
};



static inline void init_continuation(struct continuation *k,
				     void (*fn)(struct work_struct *))
{
	INIT_WORK(&k->ws, fn);
	k->input = 0;
}

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static inline void queue_continuation(struct workqueue_struct *wq,
				      struct continuation *k)
{
	queue_work(wq, &k->ws);
}

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/*----------------------------------------------------------------*/

/*
 * The batcher collects together pieces of work that need a particular
 * operation to occur before they can proceed (typically a commit).
 */

struct batcher {
	/*
         * The operation that everyone is waiting for.
         */
	
blk_status_t (*commit_op)(void *context);
	
void *commit_context;

	/*
         * This is how bios should be issued once the commit op is complete
         * (accounted_request).
         */
	
void (*issue_op)(struct bio *bio, void *context);
	
void *issue_context;

	/*
         * Queued work gets put on here after commit.
         */
	
struct workqueue_struct *wq;

	
spinlock_t lock;
	
struct list_head work_items;
	
struct bio_list bios;
	
struct work_struct commit_work;

	
bool commit_scheduled;
};



static void __commit(struct work_struct *_ws)
{
	struct batcher *b = container_of(_ws, struct batcher, commit_work);
	blk_status_t r;
	unsigned long flags;
	struct list_head work_items;
	struct work_struct *ws, *tmp;
	struct continuation *k;
	struct bio *bio;
	struct bio_list bios;

	INIT_LIST_HEAD(&work_items);
	bio_list_init(&bios);

	/*
         * We have to grab these before the commit_op to avoid a race
         * condition.
         */
	spin_lock_irqsave(&b->lock, flags);
	list_splice_init(&b->work_items, &work_items);
	bio_list_merge(&bios, &b->bios);
	bio_list_init(&b->bios);
	b->commit_scheduled = false;
	spin_unlock_irqrestore(&b->lock, flags);

	r = b->commit_op(b->commit_context);

	list_for_each_entry_safe(ws, tmp, &work_items, entry) {
		k = container_of(ws, struct continuation, ws);
		k->input = r;
		INIT_LIST_HEAD(&ws->entry); /* to avoid a WARN_ON */
		queue_work(b->wq, ws);
	}

	while ((bio = bio_list_pop(&bios))) {
		if (r) {
			bio->bi_status = r;
			bio_endio(bio);
		} else
			b->issue_op(bio, b->issue_context);
	}
}

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static void batcher_init(struct batcher *b,
			 blk_status_t (*commit_op)(void *),
			 void *commit_context,
			 void (*issue_op)(struct bio *bio, void *),
			 void *issue_context,
			 struct workqueue_struct *wq)
{
	b->commit_op = commit_op;
	b->commit_context = commit_context;
	b->issue_op = issue_op;
	b->issue_context = issue_context;
	b->wq = wq;

	spin_lock_init(&b->lock);
	INIT_LIST_HEAD(&b->work_items);
	bio_list_init(&b->bios);
	INIT_WORK(&b->commit_work, __commit);
	b->commit_scheduled = false;
}

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static void async_commit(struct batcher *b)
{
	queue_work(b->wq, &b->commit_work);
}

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static void continue_after_commit(struct batcher *b, struct continuation *k)
{
	unsigned long flags;
	bool commit_scheduled;

	spin_lock_irqsave(&b->lock, flags);
	commit_scheduled = b->commit_scheduled;
	list_add_tail(&k->ws.entry, &b->work_items);
	spin_unlock_irqrestore(&b->lock, flags);

	if (commit_scheduled)
		async_commit(b);
}

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/*
 * Bios are errored if commit failed.
 */


static void issue_after_commit(struct batcher *b, struct bio *bio)
{
       unsigned long flags;
       bool commit_scheduled;

       spin_lock_irqsave(&b->lock, flags);
       commit_scheduled = b->commit_scheduled;
       bio_list_add(&b->bios, bio);
       spin_unlock_irqrestore(&b->lock, flags);

       if (commit_scheduled)
	       async_commit(b);
}

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/*
 * Call this if some urgent work is waiting for the commit to complete.
 */


static void schedule_commit(struct batcher *b)
{
	bool immediate;
	unsigned long flags;

	spin_lock_irqsave(&b->lock, flags);
	immediate = !list_empty(&b->work_items) || !bio_list_empty(&b->bios);
	b->commit_scheduled = true;
	spin_unlock_irqrestore(&b->lock, flags);

	if (immediate)
		async_commit(b);
}

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/*
 * There are a couple of places where we let a bio run, but want to do some
 * work before calling its endio function.  We do this by temporarily
 * changing the endio fn.
 */

struct dm_hook_info {
	
bio_end_io_t *bi_end_io;
};



static void dm_hook_bio(struct dm_hook_info *h, struct bio *bio,
			bio_end_io_t *bi_end_io, void *bi_private)
{
	h->bi_end_io = bio->bi_end_io;

	bio->bi_end_io = bi_end_io;
	bio->bi_private = bi_private;
}

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static void dm_unhook_bio(struct dm_hook_info *h, struct bio *bio)
{
	bio->bi_end_io = h->bi_end_io;
}

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/*----------------------------------------------------------------*/


#define MIGRATION_POOL_SIZE 128

#define COMMIT_PERIOD HZ

#define MIGRATION_COUNT_WINDOW 10

/*
 * The block size of the device holding cache data must be
 * between 32KB and 1GB.
 */

#define DATA_DEV_BLOCK_SIZE_MIN_SECTORS (32 * 1024 >> SECTOR_SHIFT)

#define DATA_DEV_BLOCK_SIZE_MAX_SECTORS (1024 * 1024 * 1024 >> SECTOR_SHIFT)


enum cache_metadata_mode {
	
CM_WRITE,		/* metadata may be changed */
	
CM_READ_ONLY,		/* metadata may not be changed */
	
CM_FAIL
};


enum cache_io_mode {
	/*
         * Data is written to cached blocks only.  These blocks are marked
         * dirty.  If you lose the cache device you will lose data.
         * Potential performance increase for both reads and writes.
         */
	
CM_IO_WRITEBACK,

	/*
         * Data is written to both cache and origin.  Blocks are never
         * dirty.  Potential performance benfit for reads only.
         */
	
CM_IO_WRITETHROUGH,

	/*
         * A degraded mode useful for various cache coherency situations
         * (eg, rolling back snapshots).  Reads and writes always go to the
         * origin.  If a write goes to a cached oblock, then the cache
         * block is invalidated.
         */
	
CM_IO_PASSTHROUGH
};


struct cache_features {
	
enum cache_metadata_mode mode;
	
enum cache_io_mode io_mode;
	
unsigned metadata_version;
};


struct cache_stats {
	
atomic_t read_hit;
	
atomic_t read_miss;
	
atomic_t write_hit;
	
atomic_t write_miss;
	
atomic_t demotion;
	
atomic_t promotion;
	
atomic_t writeback;
	
atomic_t copies_avoided;
	
atomic_t cache_cell_clash;
	
atomic_t commit_count;
	
atomic_t discard_count;
};


struct cache {
	
struct dm_target *ti;
	
struct dm_target_callbacks callbacks;

	
struct dm_cache_metadata *cmd;

	/*
         * Metadata is written to this device.
         */
	
struct dm_dev *metadata_dev;

	/*
         * The slower of the two data devices.  Typically a spindle.
         */
	
struct dm_dev *origin_dev;

	/*
         * The faster of the two data devices.  Typically an SSD.
         */
	
struct dm_dev *cache_dev;

	/*
         * Size of the origin device in _complete_ blocks and native sectors.
         */
	
dm_oblock_t origin_blocks;
	
sector_t origin_sectors;

	/*
         * Size of the cache device in blocks.
         */
	
dm_cblock_t cache_size;

	/*
         * Fields for converting from sectors to blocks.
         */
	
sector_t sectors_per_block;
	
int sectors_per_block_shift;

	
spinlock_t lock;
	
struct list_head deferred_cells;
	
struct bio_list deferred_bios;
	
struct bio_list deferred_writethrough_bios;
	
sector_t migration_threshold;
	
wait_queue_head_t migration_wait;
	
atomic_t nr_allocated_migrations;

	/*
         * The number of in flight migrations that are performing
         * background io. eg, promotion, writeback.
         */
	
atomic_t nr_io_migrations;

	
struct rw_semaphore quiesce_lock;

	/*
         * cache_size entries, dirty if set
         */
	
atomic_t nr_dirty;
	
unsigned long *dirty_bitset;

	/*
         * origin_blocks entries, discarded if set.
         */
	
dm_dblock_t discard_nr_blocks;
	
unsigned long *discard_bitset;
	
uint32_t discard_block_size; /* a power of 2 times sectors per block */

	/*
         * Rather than reconstructing the table line for the status we just
         * save it and regurgitate.
         */
	
unsigned nr_ctr_args;
	
const char **ctr_args;

	
struct dm_kcopyd_client *copier;
	
struct workqueue_struct *wq;
	
struct work_struct deferred_bio_worker;
	
struct work_struct deferred_writethrough_worker;
	
struct work_struct migration_worker;
	
struct delayed_work waker;
	
struct dm_bio_prison_v2 *prison;

	
mempool_t *migration_pool;

	
struct dm_cache_policy *policy;
	
unsigned policy_nr_args;

	
bool need_tick_bio:1;
	
bool sized:1;
	
bool invalidate:1;
	
bool commit_requested:1;
	
bool loaded_mappings:1;
	
bool loaded_discards:1;

	/*
         * Cache features such as write-through.
         */
	
struct cache_features features;

	
struct cache_stats stats;

	/*
         * Invalidation fields.
         */
	
spinlock_t invalidation_lock;
	
struct list_head invalidation_requests;

	
struct io_tracker tracker;

	
struct work_struct commit_ws;
	
struct batcher committer;

	
struct rw_semaphore background_work_lock;
};


struct per_bio_data {
	
bool tick:1;
	
unsigned req_nr:2;
	
struct dm_bio_prison_cell_v2 *cell;
	
struct dm_hook_info hook_info;
	
sector_t len;

	/*
         * writethrough fields.  These MUST remain at the end of this
         * structure and the 'cache' member must be the first as it
         * is used to determine the offset of the writethrough fields.
         */
	
struct cache *cache;
	
dm_cblock_t cblock;
	
struct dm_bio_details bio_details;
};


struct dm_cache_migration {
	
struct continuation k;
	
struct cache *cache;

	
struct policy_work *op;
	
struct bio *overwrite_bio;
	
struct dm_bio_prison_cell_v2 *cell;

	
dm_cblock_t invalidate_cblock;
	
dm_oblock_t invalidate_oblock;
};

/*----------------------------------------------------------------*/



static bool writethrough_mode(struct cache_features *f)
{
	return f->io_mode == CM_IO_WRITETHROUGH;
}

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static bool writeback_mode(struct cache_features *f)
{
	return f->io_mode == CM_IO_WRITEBACK;
}

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static inline bool passthrough_mode(struct cache_features *f)
{
	return unlikely(f->io_mode == CM_IO_PASSTHROUGH);
}

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/*----------------------------------------------------------------*/



static void wake_deferred_bio_worker(struct cache *cache)
{
	queue_work(cache->wq, &cache->deferred_bio_worker);
}

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static void wake_deferred_writethrough_worker(struct cache *cache)
{
	queue_work(cache->wq, &cache->deferred_writethrough_worker);
}

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static void wake_migration_worker(struct cache *cache)
{
	if (passthrough_mode(&cache->features))
		return;

	queue_work(cache->wq, &cache->migration_worker);
}

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/*----------------------------------------------------------------*/



static struct dm_bio_prison_cell_v2 *alloc_prison_cell(struct cache *cache)
{
	return dm_bio_prison_alloc_cell_v2(cache->prison, GFP_NOWAIT);
}

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static void free_prison_cell(struct cache *cache, struct dm_bio_prison_cell_v2 *cell)
{
	dm_bio_prison_free_cell_v2(cache->prison, cell);
}

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static struct dm_cache_migration *alloc_migration(struct cache *cache)
{
	struct dm_cache_migration *mg;

	mg = mempool_alloc(cache->migration_pool, GFP_NOWAIT);
	if (mg) {
		mg->cache = cache;
		atomic_inc(&mg->cache->nr_allocated_migrations);
	}

	return mg;
}

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static void free_migration(struct dm_cache_migration *mg)
{
	struct cache *cache = mg->cache;

	if (atomic_dec_and_test(&cache->nr_allocated_migrations))
		wake_up(&cache->migration_wait);

	mempool_free(mg, cache->migration_pool);
}

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/*----------------------------------------------------------------*/



static inline dm_oblock_t oblock_succ(dm_oblock_t b)
{
	return to_oblock(from_oblock(b) + 1ull);
}

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static void build_key(dm_oblock_t begin, dm_oblock_t end, struct dm_cell_key_v2 *key)
{
	key->virtual = 0;
	key->dev = 0;
	key->block_begin = from_oblock(begin);
	key->block_end = from_oblock(end);
}

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/*
 * We have two lock levels.  Level 0, which is used to prevent WRITEs, and
 * level 1 which prevents *both* READs and WRITEs.
 */

#define WRITE_LOCK_LEVEL 0

#define READ_WRITE_LOCK_LEVEL 1



static unsigned lock_level(struct bio *bio)
{
	return bio_data_dir(bio) == WRITE ?
		WRITE_LOCK_LEVEL :
		READ_WRITE_LOCK_LEVEL;
}

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/*----------------------------------------------------------------
 * Per bio data
 *--------------------------------------------------------------*/

/*
 * If using writeback, leave out struct per_bio_data's writethrough fields.
 */

#define PB_DATA_SIZE_WB (offsetof(struct per_bio_data, cache))

#define PB_DATA_SIZE_WT (sizeof(struct per_bio_data))



static size_t get_per_bio_data_size(struct cache *cache)
{
	return writethrough_mode(&cache->features) ? PB_DATA_SIZE_WT : PB_DATA_SIZE_WB;
}

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static struct per_bio_data *get_per_bio_data(struct bio *bio, size_t data_size)
{
	struct per_bio_data *pb = dm_per_bio_data(bio, data_size);
	BUG_ON(!pb);
	return pb;
}

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static struct per_bio_data *init_per_bio_data(struct bio *bio, size_t data_size)
{
	struct per_bio_data *pb = get_per_bio_data(bio, data_size);

	pb->tick = false;
	pb->req_nr = dm_bio_get_target_bio_nr(bio);
	pb->cell = NULL;
	pb->len = 0;

	return pb;
}

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/*----------------------------------------------------------------*/



static void defer_bio(struct cache *cache, struct bio *bio)
{
	unsigned long flags;

	spin_lock_irqsave(&cache->lock, flags);
	bio_list_add(&cache->deferred_bios, bio);
	spin_unlock_irqrestore(&cache->lock, flags);

	wake_deferred_bio_worker(cache);
}

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static void defer_bios(struct cache *cache, struct bio_list *bios)
{
	unsigned long flags;

	spin_lock_irqsave(&cache->lock, flags);
	bio_list_merge(&cache->deferred_bios, bios);
	bio_list_init(bios);
	spin_unlock_irqrestore(&cache->lock, flags);

	wake_deferred_bio_worker(cache);
}

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/*----------------------------------------------------------------*/



static bool bio_detain_shared(struct cache *cache, dm_oblock_t oblock, struct bio *bio)
{
	bool r;
	size_t pb_size;
	struct per_bio_data *pb;
	struct dm_cell_key_v2 key;
	dm_oblock_t end = to_oblock(from_oblock(oblock) + 1ULL);
	struct dm_bio_prison_cell_v2 *cell_prealloc, *cell;

	cell_prealloc = alloc_prison_cell(cache); /* FIXME: allow wait if calling from worker */
	if (!cell_prealloc) {
		defer_bio(cache, bio);
		return false;
	}

	build_key(oblock, end, &key);
	r = dm_cell_get_v2(cache->prison, &key, lock_level(bio), bio, cell_prealloc, &cell);
	if (!r) {
		/*
                 * Failed to get the lock.
                 */
		free_prison_cell(cache, cell_prealloc);
		return r;
	}

	if (cell != cell_prealloc)
		free_prison_cell(cache, cell_prealloc);

	pb_size = get_per_bio_data_size(cache);
	pb = get_per_bio_data(bio, pb_size);
	pb->cell = cell;

	return r;
}

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/*----------------------------------------------------------------*/



static bool is_dirty(struct cache *cache, dm_cblock_t b)
{
	return test_bit(from_cblock(b), cache->dirty_bitset);
}

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static void set_dirty(struct cache *cache, dm_cblock_t cblock)
{
	if (!test_and_set_bit(from_cblock(cblock), cache->dirty_bitset)) {
		atomic_inc(&cache->nr_dirty);
		policy_set_dirty(cache->policy, cblock);
	}
}

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Joe Thornber 45 93.75% 3 75.00%
Mike Snitzer 3 6.25% 1 25.00%
Total 48 100.00% 4 100.00%

/*
 * These two are called when setting after migrations to force the policy
 * and dirty bitset to be in sync.
 */


static void force_set_dirty(struct cache *cache, dm_cblock_t cblock)
{
	if (!test_and_set_bit(from_cblock(cblock), cache->dirty_bitset))
		atomic_inc(&cache->nr_dirty);
	policy_set_dirty(cache->policy, cblock);
}

Contributors
Person Tokens Prop Commits CommitProp
Joe Thornber 46 100.00% 3 100.00%
Total 46 100.00% 3 100.00%



static void force_clear_dirty(struct cache *cache, dm_cblock_t cblock)
{
	if (test_and_clear_bit(from_cblock(cblock), cache->dirty_bitset)) {
		if (atomic_dec_return(&cache->nr_dirty) == 0)
			dm_table_event(cache->ti->table);
	}

	policy_clear_dirty(cache->policy, cblock);
}

Contributors
Person Tokens Prop Commits CommitProp
Joe Thornber 60 100.00% 3 100.00%
Total 60 100.00% 3 100.00%

/*----------------------------------------------------------------*/



static bool block_size_is_power_of_two(struct cache *cache)
{
	return cache->sectors_per_block_shift >= 0;
}

Contributors
Person Tokens Prop Commits CommitProp
Joe Thornber 18 100.00% 2 100.00%
Total 18 100.00% 2 100.00%

/* gcc on ARM generates spurious references to __udivdi3 and __umoddi3 */
#if defined(CONFIG_ARM) && __GNUC__ == 4 && __GNUC_MINOR__ <= 6

__always_inline
#endif

static dm_block_t block_div(dm_block_t b, uint32_t n)
{
	do_div(b, n);

	return b;
}

Contributors
Person Tokens Prop Commits CommitProp
Joe Thornber 25 100.00% 4 100.00%
Total 25 100.00% 4 100.00%



static dm_block_t oblocks_per_dblock(struct cache *cache)
{
	dm_block_t oblocks = cache->discard_block_size;

	if (block_size_is_power_of_two(cache))
		oblocks >>= cache->sectors_per_block_shift;
	else
		oblocks = block_div(oblocks, cache->sectors_per_block);

	return oblocks;
}

Contributors
Person Tokens Prop Commits CommitProp
Joe Thornber 43 93.48% 3 75.00%
Mike Snitzer 3 6.52% 1 25.00%
Total 46 100.00% 4 100.00%



static dm_dblock_t oblock_to_dblock(struct cache *cache, dm_oblock_t oblock)
{
	return to_dblock(block_div(from_oblock(oblock),
				   oblocks_per_dblock(cache)));
}

Contributors
Person Tokens Prop Commits CommitProp
Joe Thornber 31 100.00% 2 100.00%
Total 31 100.00% 2 100.00%



static void set_discard(struct cache *cache, dm_dblock_t b)
{
	unsigned long flags;

	BUG_ON(from_dblock(b) >= from_dblock(cache->discard_nr_blocks));
	atomic_inc(&cache->stats.discard_count);

	spin_lock_irqsave(&cache->lock, flags);
	set_bit(from_dblock(b), cache->discard_bitset);
	spin_unlock_irqrestore(&cache->lock, flags);
}

Contributors
Person Tokens Prop Commits CommitProp
Joe Thornber 73 97.33% 3 75.00%
Mike Snitzer 2 2.67% 1 25.00%
Total 75 100.00% 4 100.00%



static void clear_discard(struct cache *cache, dm_dblock_t b)
{
	unsigned long flags;

	spin_lock_irqsave(&cache->lock, flags);
	clear_bit(from_dblock(b), cache->discard_bitset);
	spin_unlock_irqrestore(&cache->lock, flags);
}

Contributors
Person Tokens Prop Commits CommitProp
Joe Thornber 50 100.00% 2 100.00%
Total 50 100.00% 2 100.00%



static bool is_discarded(struct cache *cache, dm_dblock_t b)
{
	int r;
	unsigned long flags;

	spin_lock_irqsave(&cache->lock, flags);
	r = test_bit(from_dblock(b), cache->discard_bitset);
	spin_unlock_irqrestore(&cache->lock, flags);

	return r;
}

Contributors
Person Tokens Prop Commits CommitProp
Joe Thornber 57 98.28% 3 75.00%
Mike Snitzer 1 1.72% 1 25.00%
Total 58 100.00% 4 100.00%



static bool is_discarded_oblock(struct cache *cache, dm_oblock_t b)
{
	int r;
	unsigned long flags;

	spin_lock_irqsave(&cache->lock, flags);
	r = test_bit(from_dblock(oblock_to_dblock(cache, b)),
		     cache->discard_bitset);
	spin_unlock_irqrestore(&cache->lock, flags);

	return r;
}

Contributors
Person Tokens Prop Commits CommitProp
Joe Thornber 62 98.41% 3 75.00%
Mike Snitzer 1 1.59% 1 25.00%
Total 63 100.00% 4 100.00%

/*----------------------------------------------------------------
 * Remapping
 *--------------------------------------------------------------*/


static void remap_to_origin(struct cache *cache, struct bio *bio)
{
	bio_set_dev(bio, cache->origin_dev->bdev);
}

Contributors
Person Tokens Prop Commits CommitProp
Joe Thornber 23 85.19% 3 75.00%
Christoph Hellwig 4 14.81% 1 25.00%
Total 27 100.00% 4 100.00%



static void remap_to_cache(struct cache *cache, struct bio *bio,
			   dm_cblock_t cblock)
{
	sector_t bi_sector = bio->bi_iter.bi_sector;
	sector_t block = from_cblock(cblock);

	bio_set_dev(bio, cache->cache_dev->bdev);
	if (!block_size_is_power_of_two(cache))
		bio->bi_iter.bi_sector =
			(block * cache->sectors_per_block) +
			sector_div(bi_sector, cache->sectors_per_block);
	else
		bio->bi_iter.bi_sector =
			(block << cache->sectors_per_block_shift) |
			(bi_sector & (cache->sectors_per_block - 1));
}

Contributors
Person Tokens Prop Commits CommitProp
Joe Thornber 100 95.24% 2 50.00%
Christoph Hellwig 4 3.81% 1 25.00%
Mike Snitzer 1 0.95% 1 25.00%
Total 105 100.00% 4 100.00%



static void check_if_tick_bio_needed(struct cache *cache, struct bio *bio)
{
	unsigned long flags;
	size_t pb_data_size = get_per_bio_data_size(cache);
	struct per_bio_data *pb = get_per_bio_data(bio, pb_data_size);

	spin_lock_irqsave(&cache->lock, flags);
	if (cache->need_tick_bio && !op_is_flush(bio->bi_opf) &&
	    bio_op(bio) != REQ_OP_DISCARD) {
		pb->tick = true;
		cache->need_tick_bio = false;
	}
	spin_unlock_irqrestore(&cache->lock, flags);
}

Contributors
Person Tokens Prop Commits CommitProp
Joe Thornber 92 96.84% 2 66.67%
Mike Snitzer 3 3.16% 1 33.33%
Total 95 100.00% 3 100.00%



static void remap_to_origin_clear_discard(struct cache *cache, struct bio *bio,
					  dm_oblock_t oblock)
{
	// FIXME: this is called way too much.
	check_if_tick_bio_needed(cache, bio);
	remap_to_origin(cache, bio);
	if (bio_data_dir(bio) == WRITE)
		clear_discard(cache, oblock_to_dblock(cache, oblock));
}

Contributors
Person Tokens Prop Commits CommitProp
Joe Thornber 50 90.91% 5 83.33%
Anssi Hannula 5 9.09% 1 16.67%
Total 55 100.00% 6 100.00%



static void remap_to_cache_dirty(struct cache *cache, struct bio *bio,
				 dm_oblock_t oblock, dm_cblock_t cblock)
{
	check_if_tick_bio_needed(cache, bio);
	remap_to_cache(cache, bio, cblock);
	if (bio_data_dir(bio) == WRITE) {
		set_dirty(cache, cblock);
		clear_discard(cache, oblock_to_dblock(cache, oblock));
	}
}

Contributors
Person Tokens Prop Commits CommitProp
Joe Thornber 68 100.00% 2 100.00%
Total 68 100.00% 2 100.00%



static dm_oblock_t get_bio_block(struct cache *cache, struct bio *bio)
{
	sector_t block_nr = bio->bi_iter.bi_sector;

	if (!block_size_is_power_of_two(cache))
		(void) sector_div(block_nr, cache->sectors_per_block);
	else
		block_nr >>= cache->sectors_per_block_shift;

	return to_oblock(block_nr);
}

Contributors
Person Tokens Prop Commits CommitProp
Joe Thornber 55 94.83% 2 66.67%
Heinz Mauelshagen 3 5.17% 1 33.33%
Total 58 100.00% 3 100.00%



static bool accountable_bio(struct cache *cache, struct bio *bio)
{
	return bio_op(bio) != REQ_OP_DISCARD;
}

Contributors
Person Tokens Prop Commits CommitProp
Joe Thornber 22 91.67% 2 66.67%
Heinz Mauelshagen 2 8.33% 1 33.33%
Total 24 100.00% 3 100.00%



static void accounted_begin(struct cache *cache, struct bio *bio)
{
	size_t pb_data_size = get_per_bio_data_size(cache);
	struct per_bio_data *pb = get_per_bio_data(bio, pb_data_size);

	if (accountable_bio(cache, bio)) {
		pb->len = bio_sectors(bio);
		iot_io_begin(&cache->tracker, pb->len);
	}
}

Contributors
Person Tokens Prop Commits CommitProp
Joe Thornber 65 95.59% 4 80.00%
Mike Snitzer 3 4.41% 1 20.00%
Total 68 100.00% 5 100.00%



static void accounted_complete(struct cache *cache, struct bio *bio)
{
	size_t pb_data_size = get_per_bio_data_size(cache);
	struct per_bio_data *pb = get_per_bio_data(bio, pb_data_size);

	iot_io_end(&cache->tracker, pb->len);
}

Contributors
Person Tokens Prop Commits CommitProp
Joe Thornber 42 87.50% 3 60.00%
Mike Snitzer 4 8.33% 1 20.00%
Heinz Mauelshagen 2 4.17% 1 20.00%
Total 48 100.00% 5 100.00%



static void accounted_request(struct cache *cache, struct bio *bio)
{
	accounted_begin(cache, bio);
	generic_make_request(bio);
}

Contributors
Person Tokens Prop Commits CommitProp
Joe Thornber 26 92.86% 3 75.00%
Heinz Mauelshagen 2 7.14% 1 25.00%
Total 28 100.00% 4 100.00%



static void issue_op(struct bio *bio, void *context)
{
	struct cache *cache = context;
	accounted_request(cache, bio);
}

Contributors
Person Tokens Prop Commits CommitProp
Joe Thornber 29 100.00% 2 100.00%
Total 29 100.00% 2 100.00%



static void defer_writethrough_bio(struct cache *cache, struct bio *bio)
{
	unsigned long flags;

	spin_lock_irqsave(&cache->lock, flags);
	bio_list_add(&cache->deferred_writethrough_bios, bio);
	spin_unlock_irqrestore(&cache->lock, flags);

	wake_deferred_writethrough_worker(cache);
}

Contributors
Person Tokens Prop Commits CommitProp
Joe Thornber 55 100.00% 3 100.00%
Total 55 100.00% 3 100.00%



static void writethrough_endio(struct bio *bio)
{
	struct per_bio_data *pb = get_per_bio_data(bio, PB_DATA_SIZE_WT);

	dm_unhook_bio(&pb->hook_info, bio);

	if (bio->bi_status) {
		bio_endio(bio);
		return;
	}

	dm_bio_restore(&pb->bio_details, bio);
	remap_to_cache(pb->cache, bio, pb->cblock);

	/*
         * We can't issue this bio directly, since we're in interrupt
         * context.  So it gets put on a bio list for processing by the
         * worker thread.
         */
	defer_writethrough_bio(pb->cache, bio);
}

Contributors
Person Tokens Prop Commits CommitProp
Joe Thornber 67 83.75% 4 57.14%
Mike Snitzer 10 12.50% 1 14.29%
Christoph Hellwig 3 3.75% 2 28.57%
Total 80 100.00% 7 100.00%

/*
 * FIXME: send in parallel, huge latency as is.
 * When running in writethrough mode we need to send writes to clean blocks
 * to both the cache and origin devices.  In future we'd like to clone the
 * bio and send them in parallel, but for now we're doing them in
 * series as this is easier.
 */


static void remap_to_origin_then_cache(struct cache *cache, struct bio *bio,
				       dm_oblock_t oblock, dm_cblock_t cblock)
{
	struct per_bio_data *pb = get_per_bio_data(bio, PB_DATA_SIZE_WT);

	pb->cache = cache;
	pb->cblock = cblock;
	dm_hook_bio(&pb->hook_info, bio, writethrough_endio, NULL);
	dm_bio_record(&pb->bio_details, bio);

	remap_to_origin_clear_discard(pb->cache, bio, oblock);
}

Contributors
Person Tokens Prop Commits CommitProp
Joe Thornber 81 100.00% 5 100.00%
Total 81 100.00% 5 100.00%

/*----------------------------------------------------------------
 * Failure modes
 *--------------------------------------------------------------*/


static enum cache_metadata_mode get_cache_mode(struct cache *cache)
{
	return cache->features.mode;
}

Contributors
Person Tokens Prop Commits CommitProp
Joe Thornber 19 100.00% 2 100.00%
Total 19 100.00% 2 100.00%



static const char *cache_device_name(struct cache *cache)
{
	return dm_device_name(dm_table_get_md(cache->ti->table));
}

Contributors
Person Tokens Prop Commits CommitProp
Joe Thornber 26 100.00% 3 100.00%
Total 26 100.00% 3 100.00%



static void notify_mode_switch(struct cache *cache, enum cache_metadata_mode mode)
{
	const char *descs[] = {
		"write",
		"read-only",
		"fail"
	};

	dm_table_event(cache->ti->table);
	DMINFO("%s: switching cache to %s mode",
	       cache_device_name(cache), descs[(int)mode]);
}

Contributors
Person Tokens Prop Commits CommitProp
Joe Thornber 56 100.00% 4 100.00%
Total 56 100.00% 4 100.00%



static void set_cache_mode(struct cache *cache, enum cache_metadata_mode new_mode)
{
	bool needs_check;
	enum cache_metadata_mode old_mode = get_cache_mode(cache);

	if (dm_cache_metadata_needs_check(cache->cmd, &needs_check)) {
		DMERR("%s: unable to read needs_check flag, setting failure mode.",
		      cache_device_name(cache));
		new_mode = CM_FAIL;
	}

	if (new_mode == CM_WRITE && needs_check) {
		DMERR("%s: unable to switch cache to write mode until repaired.",
		      cache_device_name(cache));
		if (old_mode != new_mode)
			new_mode = old_mode;
		else
			new_mode = CM_READ_ONLY;
	}

	/* Never move out of fail mode */
	if (old_mode == CM_FAIL)
		new_mode = CM_FAIL;

	switch (new_mode) {
	case CM_FAIL:
	case CM_READ_ONLY:
		dm_cache_metadata_set_read_only(cache->cmd);
		break;

	case CM_WRITE:
		dm_cache_metadata_set_read_write(cache->cmd);
		break;
	}

	cache->features.mode = new_mode;

	if (new_mode != old_mode)
		notify_mode_switch(cache, new_mode);
}

Contributors
Person Tokens Prop Commits CommitProp
Joe Thornber 153 100.00% 5 100.00%
Total 153 100.00% 5 100.00%



static void abort_transaction(struct cache *cache)
{
	const char *dev_name = cache_device_name(cache);

	if (get_cache_mode(cache) >= CM_READ_ONLY)
		return;

	if (dm_cache_metadata_set_needs_check(cache->cmd)) {
		DMERR("%s: failed to set 'needs_check' flag in metadata", dev_name);
		set_cache_mode(cache, CM_FAIL);
	}

	DMERR_LIMIT("%s: aborting current metadata transaction", dev_name);
	if (dm_cache_metadata_abort(cache->cmd)) {
		DMERR("%s: failed to abort metadata transaction", dev_name);
		set_cache_mode(cache, CM_FAIL);
	}
}

Contributors
Person Tokens Prop Commits CommitProp
Joe Thornber 88 100.00% 2 100.00%
Total 88 100.00% 2 100.00%



static void metadata_operation_failed(struct cache *cache, const char *op, int r)
{
	DMERR_LIMIT("%s: metadata operation '%s' failed: error = %d",
		    cache_device_name(cache), op, r);
	abort_transaction(cache);
	set_cache_mode(cache, CM_READ_ONLY);
}

Contributors
Person Tokens Prop Commits CommitProp
Joe Thornber 45 100.00% 2 100.00%
Total 45 100.00% 2 100.00%

/*----------------------------------------------------------------*/



static void load_stats(struct cache *cache)
{
	struct dm_cache_statistics stats;

	dm_cache_metadata_get_stats(cache->cmd, &stats);
	atomic_set(&cache->stats.read_hit, stats.read_hits);
	atomic_set(&cache->stats.read_miss, stats.read_misses);
	atomic_set(&cache->stats.write_hit, stats.write_hits);
	atomic_set(&cache->stats.write_miss, stats.write_misses);
}

Contributors
Person Tokens Prop Commits CommitProp
Joe Thornber 81 100.00% 2 100.00%
Total 81 100.00% 2 100.00%



static void save_stats(struct cache *cache)
{
	struct dm_cache_statistics stats;

	if (get_cache_mode(cache) >= CM_READ_ONLY)
		return;

	stats.read_hits = atomic_read(&cache->stats.read_hit);
	stats.read_misses = atomic_read(&cache->stats.read_miss);
	stats.write_hits = atomic_read(&cache->stats.write_hit);
	stats.write_misses = atomic_read(&cache->stats.write_miss);

	dm_cache_metadata_set_stats(cache->cmd, &stats);
}

Contributors
Person Tokens Prop Commits CommitProp
Joe Thornber 91 100.00% 2 100.00%
Total 91 100.00% 2 100.00%



static void update_stats(struct cache_stats *stats, enum policy_operation op)
{
	switch (op) {
	case POLICY_PROMOTE:
		atomic_inc(&stats->promotion);
		break;

	case POLICY_DEMOTE:
		atomic_inc(&stats->demotion);
		break;

	case POLICY_WRITEBACK:
		atomic_inc(&stats->writeback);
		break;
	}
}

Contributors
Person Tokens Prop Commits CommitProp
Joe Thornber 57 100.00% 2 100.00%
Total 57 100.00% 2 100.00%

/*----------------------------------------------------------------
 * Migration processing
 *
 * Migration covers moving data from the origin device to the cache, or
 * vice versa.
 *--------------------------------------------------------------*/



static void inc_io_migrations(struct cache *cache)
{
	atomic_inc(&cache->nr_io_migrations);
}

Contributors
Person Tokens Prop Commits CommitProp
Joe Thornber 19 100.00% 4 100.00%
Total 19 100.00% 4 100.00%



static void dec_io_migrations(struct cache *cache)
{
	atomic_dec(&cache->nr_io_migrations);
}

Contributors
Person Tokens Prop Commits CommitProp
Joe Thornber 19 100.00% 2 100.00%
Total 19 100.00% 2 100.00%



static bool discard_or_flush(struct bio *bio)
{
	return bio_op(bio) == REQ_OP_DISCARD || op_is_flush(bio->bi_opf);
}

Contributors
Person Tokens Prop Commits CommitProp
Joe Thornber 26 100.00% 2 100.00%
Total 26 100.00% 2 100.00%



static void calc_discard_block_range(struct cache *cache, struct bio *bio,
				     dm_dblock_t *b, dm_dblock_t *e)
{
	sector_t sb = bio->bi_iter.bi_sector;
	sector_t se = bio_end_sector(bio);

	*b = to_dblock(dm_sector_div_up(sb, cache->discard_block_size));

	if (se - sb < cache->discard_block_size)
		*e = *b;
	else
		*e = to_dblock(block_div(se, cache->discard_block_size));
}

Contributors
Person Tokens Prop Commits CommitProp
Joe Thornber 88 100.00% 2 100.00%
Total 88 100.00% 2 100.00%

/*----------------------------------------------------------------*/



static void prevent_background_work(struct cache *cache)
{
	lockdep_off();
	down_write(&cache->background_work_lock);
	lockdep_on();
}

Contributors
Person Tokens Prop Commits CommitProp
Joe Thornber 25 100.00% 3 100.00%
Total 25 100.00% 3 100.00%



static void allow_background_work(struct cache *cache)
{
	lockdep_off();
	up_write(&cache->background_work_lock);
	lockdep_on();
}

Contributors
Person Tokens Prop Commits CommitProp
Joe Thornber 25 100.00% 2 100.00%
Total 25 100.00% 2 100.00%



static bool background_work_begin(struct cache *cache)
{
	bool r;

	lockdep_off();
	r = down_read_trylock(&cache->background_work_lock);
	lockdep_on();

	return r;
}

Contributors
Person Tokens Prop Commits CommitProp
Joe Thornber 33 100.00% 2 100.00%
Total 33 100.00% 2 100.00%



static void background_work_end(struct cache *cache)
{
	lockdep_off();
	up_read(&cache->background_work_lock);
	lockdep_on();
}

Contributors
Person Tokens Prop Commits CommitProp
Joe Thornber 25 100.00% 3 100.00%
Total 25 100.00% 3 100.00%

/*----------------------------------------------------------------*/



static void quiesce(struct dm_cache_migration *mg,
		    void (*continuation)(struct work_struct *))
{
	init_continuation(&mg->k, continuation);
	dm_cell_quiesce_v2(mg->cache->prison, mg->cell, &mg->k.ws);
}

Contributors
Person Tokens Prop Commits CommitProp
Joe Thornber 52 100.00% 3 100.00%
Total 52 100.00% 3 100.00%



static struct dm_cache_migration *ws_to_mg(struct work_struct *ws)
{
	struct continuation *k = container_of(ws, struct continuation, ws);
	return container_of(k, struct dm_cache_migration, k);
}

Contributors
Person Tokens Prop Commits CommitProp
Joe Thornber 38 97.44% 2 66.67%
Mike Snitzer 1 2.56% 1 33.33%
Total 39 100.00% 3 100.00%



static void copy_complete(int read_err, unsigned long write_err, void *context)
{
	struct dm_cache_migration *mg = container_of(context, struct dm_cache_migration, k);

	if (read_err || write_err)
		mg->k.input = BLK_STS_IOERR;

	queue_continuation(mg->cache->wq, &mg->k);
}

Contributors
Person Tokens Prop Commits CommitProp
Joe Thornber 59 98.33% 2 66.67%
Christoph Hellwig 1 1.67% 1 33.33%
Total 60 100.00% 3 100.00%



static int copy(struct dm_cache_migration *mg, bool promote)
{
	int r;
	struct dm_io_region o_region, c_region;
	struct cache *cache = mg->cache;

	o_region.bdev = cache->origin_dev->bdev;
	o_region.sector = from_oblock(mg->op->oblock) * cache->sectors_per_block;
	o_region.count = cache->sectors_per_block;

	c_region.bdev = cache->cache_dev->bdev;
	c_region.sector = from_cblock(mg->op->cblock) * cache->sectors_per_block;
	c_region.count = cache->sectors_per_block;

	if (promote)
		r = dm_kcopyd_copy(cache->copier, &o_region, 1, &c_region, 0, copy_complete, &mg->k);
	else
		r = dm_kcopyd_copy(cache->copier, &c_region, 1, &o_region, 0, copy_complete, &mg->k);

	return r;
}

Contributors
Person Tokens Prop Commits CommitProp
Joe Thornber 162 100.00% 4 100.00%
Total 162 100.00% 4 100.00%



static void bio_drop_shared_lock(struct cache *cache, struct bio *bio)
{
	size_t pb_data_size = get_per_bio_data_size(cache);
	struct per_bio_data *pb = get_per_bio_data(bio, pb_data_size);

	if (pb->cell && dm_cell_put_v2(cache->prison, pb->cell))
		free_prison_cell(cache, pb->cell);
	pb->cell = NULL;
}

Contributors
Person Tokens Prop Commits CommitProp
Joe Thornber 68 100.00% 3 100.00%
Total 68 100.00% 3 100.00%



static void overwrite_endio(struct bio *bio)
{
	struct dm_cache_migration *mg = bio->bi_private;
	struct cache *cache = mg->cache;
	size_t pb_data_size = get_per_bio_data_size(cache);
	struct per_bio_data *pb = get_per_bio_data(bio, pb_data_size);

	dm_unhook_bio(&pb->hook_info, bio);

	if (bio->bi_status)
		mg->k.input = bio->bi_status;

	queue_continuation(mg->cache->wq, &mg->k);
}

Contributors
Person Tokens Prop Commits CommitProp
Joe Thornber 87 97.75% 4 80.00%
Christoph Hellwig 2 2.25% 1 20.00%
Total 89 100.00% 5 100.00%



static void overwrite(struct dm_cache_migration *mg,
		      void (*continuation)(struct work_struct *))
{
	struct bio *bio = mg->overwrite_bio;
	size_t pb_data_size = get_per_bio_data_size(mg->cache);
	struct per_bio_data *pb = get_per_bio_data(bio, pb_data_size);

	dm_hook_bio(&pb->hook_info, bio, overwrite_endio, mg);

	/*
         * The overwrite bio is part of the copy operation, as such it does
         * not set/clear discard or dirty flags.
         */
	if (mg->op->op == POLICY_PROMOTE)
		remap_to_cache(mg->cache, bio, mg->op->cblock);
	else
		remap_to_origin(mg->cache, bio);

	init_continuation(&mg->k, continuation);
	accounted_request(mg->cache, bio);
}

Contributors
Person Tokens Prop Commits CommitProp
Joe Thornber 122 100.00% 3 100.00%
Total 122 100.00% 3 100.00%

/*
 * Migration steps:
 *
 * 1) exclusive lock preventing WRITEs
 * 2) quiesce
 * 3) copy or issue overwrite bio
 * 4) upgrade to exclusive lock preventing READs and WRITEs
 * 5) quiesce
 * 6) update metadata and commit
 * 7) unlock
 */


static void mg_complete(struct dm_cache_migration *mg, bool success)
{
	struct bio_list bios;
	struct cache *cache = mg->cache;
	struct policy_work *op = mg->op;
	dm_cblock_t cblock = op->cblock;

	if (success)
		update_stats(&cache->stats, op->op);

	switch (op->op) {
	case POLICY_PROMOTE:
		clear_discard(cache, oblock_to_dblock(cache, op->oblock));
		policy_complete_background_work(cache->policy, op, success);

		if (mg->overwrite_bio) {
			if (success)
				force_set_dirty(cache, cblock);
			else if (mg->k.input)
				mg->overwrite_bio->bi_status = mg->k.input;
			else
				mg->overwrite_bio->bi_status = BLK_STS_IOERR;
			bio_endio(mg->overwrite_bio);
		} else {
			if (success)
				force_clear_dirty(cache, cblock);
			dec_io_migrations(cache);
		}
		break;

	case POLICY_DEMOTE:
		/*
                 * We clear dirty here to update the nr_dirty counter.
                 */
		if (success)
			force_clear_dirty(cache, cblock);
		policy_complete_background_work(cache->policy, op, success);
		dec_io_migrations(cache);
		break;

	case POLICY_WRITEBACK:
		if (success)
			force_clear_dirty(cache, cblock);
		policy_complete_background_work(cache->policy, op, success);
		dec_io_migrations(cache);
		break;
	}

	bio_list_init(&bios);
	if (mg->cell) {
		if (dm_cell_unlock_v2(cache->prison, mg->cell, &bios))
			free_prison_cell(cache, mg->cell);
	}

	free_migration(mg);
	defer_bios(cache, &bios);
	wake_migration_worker(cache);

	background_work_end(cache);
}

Contributors
Person Tokens Prop Commits CommitProp
Joe Thornber 277 93.58% 3 75.00%
Christoph Hellwig 19 6.42% 1 25.00%
Total 296 100.00% 4 100.00%



static void mg_success(struct work_struct *ws)
{
	struct dm_cache_migration *mg = ws_to_mg(ws);
	mg_complete(mg, mg->k.input == 0);
}

Contributors
Person Tokens Prop Commits CommitProp
Joe Thornber 34 100.00% 2 100.00%
Total 34 100.00% 2 100.00%



static void mg_update_metadata(struct work_struct *ws)
{
	int r;
	struct dm_cache_migration *mg = ws_to_mg(ws);
	struct cache *cache = mg->cache;
	struct policy_work *op = mg->op;

	switch (op->op) {
	case POLICY_PROMOTE:
		r = dm_cache_insert_mapping(cache->cmd, op->cblock, op->oblock);
		if (r) {
			DMERR_LIMIT("%s: migration failed; couldn't insert mapping",
				    cache_device_name(cache));
			metadata_operation_failed(cache, "dm_cache_insert_mapping", r);

			mg_complete(mg, false);
			return;
		}
		mg_complete(mg, true);
		break;

	case POLICY_DEMOTE:
		r = dm_cache_remove_mapping(cache->cmd, op->cblock);
		if (r) {
			DMERR_LIMIT("%s: migration failed; couldn't update on disk metadata",
				    cache_device_name(cache));
			metadata_operation_failed(cache, "dm_cache_remove_mapping", r);

			mg_complete(mg, false);
			return;
		}

		/*
                 * It would be nice if we only had to commit when a REQ_FLUSH
                 * comes through.  But there's one scenario that we have to
                 * look out for:
                 *
                 * - vblock x in a cache block
                 * - domotion occurs
                 * - cache block gets reallocated and over written
                 * - crash
                 *
                 * When we recover, because there was no commit the cache will
                 * rollback to having the data for vblock x in the cache block.
                 * But the cache block has since been overwritten, so it'll end
                 * up pointing to data that was never in 'x' during the history
                 * of the device.
                 *
                 * To avoid this issue we require a commit as part of the
                 * demotion operation.
                 */
		init_continuation(&mg->k, mg_success);
		continue_after_commit(&cache->committer, &mg->k);
		schedule_commit(&cache->committer);
		break;

	case POLICY_WRITEBACK:
		mg_complete(mg, true);
		break;
	}
}

Contributors
Person Tokens Prop Commits CommitProp
Joe Thornber 204 100.00% 3 100.00%
Total 204 100.00% 3 100.00%



static void mg_update_metadata_after_copy(struct work_struct *ws)
{
	struct dm_cache_migration *mg = ws_to_mg(ws);

	/*
         * Did the copy succeed?
         */
	if (mg->k.input)
		mg_complete(mg, false);
	else
		mg_update_metadata(ws);
}

Contributors
Person Tokens Prop Commits CommitProp
Joe Thornber 43 100.00% 2 100.00%
Total 43 100.00% 2 100.00%



static void mg_upgrade_lock(struct work_struct *ws)
{
	int r;
	struct dm_cache_migration *mg = ws_to_mg(ws);

	/*
         * Did the copy succeed?
         */
	if (mg->k.input)
		mg_complete(mg, false);

	else {
		/*
                 * Now we want the lock to prevent both reads and writes.
                 */
		r = dm_cell_lock_promote_v2(mg->cache->prison, mg->cell,
					    READ_WRITE_LOCK_LEVEL);
		if (r < 0)
			mg_complete(mg, false);

		else if (r)
			quiesce(mg, mg_update_metadata);

		else
			mg_update_metadata(ws);
	}
}

Contributors
Person Tokens Prop Commits CommitProp
Joe Thornber 92 100.00% 3 100.00%
Total 92 100.00% 3 100.00%



static void mg_copy(struct work_struct *ws)
{
	int r;
	struct dm_cache_migration *mg = ws_to_mg(ws);

	if (mg->overwrite_bio) {
		/*
                 * It's safe to do this here, even though it's new data
                 * because all IO has been locked out of the block.
                 *
                 * mg_lock_writes() already took READ_WRITE_LOCK_LEVEL
                 * so _not_ using mg_upgrade_lock() as continutation.
                 */
		overwrite(mg, mg_update_metadata_after_copy);

	} else {
		struct cache *cache = mg->cache;
		struct policy_work *op = mg->op;
		bool is_policy_promote = (op->op == POLICY_PROMOTE);

		if ((!is_policy_promote && !is_dirty(cache, op->cblock)) ||
		    is_discarded_oblock(cache, op->oblock)) {
			mg_upgrade_lock(ws);
			return;
		}

		init_continuation(&mg->k, mg_upgrade_lock);

		r = copy(mg, is_policy_promote);
		if (r) {
			DMERR_LIMIT("%s: migration copy failed", cache_device_name(cache));
			mg->k.input = BLK_STS_IOERR;
			mg_complete(mg, false);
		}
	}
}

Contributors
Person Tokens Prop Commits CommitProp
Joe Thornber 155 99.36% 7 87.50%
Christoph Hellwig 1 0.64% 1 12.50%
Total 156 100.00% 8 100.00%



static int mg_lock_writes(struct dm_cache_migration *mg)
{
	int r;
	struct dm_cell_key_v2 key;
	struct cache *cache = mg->cache;
	struct dm_bio_prison_cell_v2 *prealloc;

	prealloc = alloc_prison_cell(cache);
	if (!prealloc) {
		DMERR_LIMIT("%s: alloc_prison_cell failed", cache_device_name(cache));
		mg_complete(mg, false);
		return -ENOMEM;
	}

	/*
         * Prevent writes to the block, but allow reads to continue.
         * Unless we're using an overwrite bio, in which case we lock
         * everything.
         */
	build_key(mg->op->oblock, oblock_succ(mg->op->oblock), &key);
	r = dm_cell_lock_v2(cache->prison, &key,
			    mg->overwrite_bio ?  READ_WRITE_LOCK_LEVEL : WRITE_LOCK_LEVEL,
			    prealloc, &mg->cell);
	if (r < 0) {
		free_prison_cell(cache, prealloc);
		mg_complete(mg, false);
		return r;
	}

	if (mg->cell != prealloc)
		free_prison_cell(cache, prealloc);

	if (r == 0)
		mg_copy(&mg->k.ws);
	else
		quiesce(mg, mg_copy);

	return 0;
}

Contributors
Person Tokens Prop Commits CommitProp
Joe Thornber 183 100.00% 4 100.00%
Total 183 100.00% 4 100.00%



static int mg_start(struct cache *cache, struct policy_work *op, struct bio *bio)
{
	struct dm_cache_migration *mg;

	if (!background_work_begin(cache)) {
		policy_complete_background_work(cache->policy, op, false);
		return -EPERM;
	}

	mg = alloc_migration(cache);
	if (!mg) {
		policy_complete_background_work(cache->policy, op, false);
		background_work_end(cache);
		return -ENOMEM;
	}

	memset(mg, 0, sizeof(*mg));

	mg->cache = cache;
	mg->op = op;
	mg->overwrite_bio = bio;

	if (!bio)
		inc_io_migrations(cache);

	return mg_lock_writes(mg);
}

Contributors
Person Tokens Prop Commits CommitProp
Joe Thornber 131 99.24% 3 75.00%
Mike Snitzer 1 0.76% 1 25.00%
Total 132 100.00% 4 100.00%

/*----------------------------------------------------------------
 * invalidation processing
 *--------------------------------------------------------------*/



static void invalidate_complete(struct dm_cache_migration *mg, bool success)
{
	struct bio_list bios;
	struct cache *cache = mg->cache;

	bio_list_init(&bios);
	if (dm_cell_unlock_v2(cache->prison, mg->cell, &bios))
		free_prison_cell(cache, mg->cell);

	if (!success && mg->overwrite_bio)
		bio_io_error(mg->overwrite_bio);

	free_migration(mg);
	defer_bios(cache, &bios);

	background_work_end(cache);
}

Contributors
Person Tokens Prop Commits CommitProp
Joe Thornber 92 100.00% 3 100.00%
Total 92 100.00% 3 100.00%



static void invalidate_completed(struct work_struct *ws)
{
	struct dm_cache_migration *mg = ws_to_mg(ws);
	invalidate_complete(mg, !mg->k.input);
}

Contributors
Person Tokens Prop Commits CommitProp
Joe Thornber 33 100.00% 2 100.00%
Total 33 100.00% 2 100.00%



static int invalidate_cblock(struct cache *cache, dm_cblock_t cblock)
{
	int r = policy_invalidate_mapping(cache->policy, cblock);
	if (!r) {
		r = dm_cache_remove_mapping(cache->cmd, cblock);
		if (r) {
			DMERR_LIMIT("%s: invalidation failed; couldn't update on disk metadata",
				    cache_device_name(cache));
			metadata_operation_failed(cache, "dm_cache_remove_mapping", r);
		}

	} else if (r == -ENODATA) {
		/*
                 * Harmless, already unmapped.
                 */
		r = 0;

	} else
		DMERR("%s: policy_invalidate_mapping failed", cache_device_name(cache));

	return r;
}

Contributors
Person Tokens Prop Commits CommitProp
Joe Thornber 98 100.00% 2 100.00%
Total 98 100.00% 2 100.00%



static void invalidate_remove(struct work_struct *ws)
{
	int r;
	struct dm_cache_migration *mg = ws_to_mg(ws);
	struct cache *cache = mg->cache;

	r = invalidate_cblock(cache, mg->invalidate_cblock);
	if (r) {
		invalidate_complete(mg, false);
		return;
	}

	init_continuation(&mg->k, invalidate_completed);
	continue_after_commit(&cache->committer, &mg->k);
	remap_to_origin_clear_discard(cache, mg->overwrite_bio, mg->invalidate_oblock);
	mg->overwrite_bio = NULL;
	schedule_commit(&cache->committer);
}

Contributors
Person Tokens Prop Commits CommitProp
Joe Thornber 96 88.89% 3 75.00%
Heinz Mauelshagen 12 11.11% 1 25.00%
Total 108 100.00% 4 100.00%



static int invalidate_lock(struct dm_cache_migration *mg)
{
	int r;
	struct dm_cell_key_v2 key;
	struct cache *cache = mg->cache;
	struct dm_bio_prison_cell_v2 *prealloc;

	prealloc = alloc_prison_cell(cache);
	if (!prealloc) {
		invalidate_complete(mg, false);
		return -ENOMEM;
	}

	build_key(mg->invalidate_oblock, oblock_succ(mg->invalidate_oblock), &key);
	r = dm_cell_lock_v2(cache->prison, &key,
			    READ_WRITE_LOCK_LEVEL, prealloc, &mg->cell);
	if (r < 0) {
		free_prison_cell(cache, prealloc);
		invalidate_complete(mg, false);
		return r;
	}

	if (mg->cell != prealloc)
		free_prison_cell(cache, prealloc);

	if (r)
		quiesce(mg, invalidate_remove);

	else {
		/*
                 * We can't call invalidate_remove() directly here because we
                 * might still be in request context.
                 */
		init_continuation(&mg->k, invalidate_remove);
		queue_work(cache->wq, &mg->k.ws);
	}

	return 0;
}

Contributors
Person Tokens Prop Commits CommitProp
Joe Thornber 176 99.44% 3 75.00%
Mike Snitzer 1 0.56% 1 25.00%
Total 177 100.00% 4 100.00%



static int invalidate_start(struct cache *cache, dm_cblock_t cblock,
			    dm_oblock_t oblock, struct bio *bio)
{
	struct dm_cache_migration *mg;

	if (!background_work_begin(cache))
		return -EPERM;

	mg = alloc_migration(cache);
	if (!mg) {
		background_work_end(cache);
		return -ENOMEM;
	}

	memset(mg, 0, sizeof(*mg));

	mg->cache = cache;
	mg->overwrite_bio = bio;
	mg->invalidate_cblock = cblock;
	mg->invalidate_oblock = oblock;

	return invalidate_lock(mg);
}

Contributors
Person Tokens Prop Commits CommitProp
Joe Thornber 104 99.05% 2 66.67%
Mike Snitzer 1 0.95% 1 33.33%
Total 105 100.00% 3 100.00%

/*----------------------------------------------------------------
 * bio processing
 *--------------------------------------------------------------*/


enum busy {
	
IDLE,
	
BUSY
};



static enum busy spare_migration_bandwidth(struct cache *cache)
{
	bool idle = iot_idle_for(&cache->tracker, HZ);
	sector_t current_volume = (atomic_read(&cache->nr_io_migrations) + 1) *
		cache->sectors_per_block;

	if (idle && current_volume <= cache->migration_threshold)
		return IDLE;
	else
		return BUSY;
}

Contributors
Person Tokens Prop Commits CommitProp
Joe Thornber 59 96.72% 4 80.00%
Mike Snitzer 2 3.28% 1 20.00%
Total 61 100.00% 5 100.00%



static void inc_hit_counter(struct cache *cache, struct bio *bio)
{
	atomic_inc(bio_data_dir(bio) == READ ?
		   &cache->stats.read_hit : &cache->stats.write_hit);
}

Contributors
Person Tokens Prop Commits CommitProp
Joe Thornber 40 100.00% 2 100.00%
Total 40 100.00% 2 100.00%



static void inc_miss_counter(struct cache *cache, struct bio *bio)
{
	atomic_inc(bio_data_dir(bio) == READ ?
		   &cache->stats.read_miss : &cache->stats.write_miss);
}

Contributors
Person Tokens Prop Commits CommitProp
Joe Thornber 40 100.00% 2 100.00%
Total 40 100.00% 2 100.00%

/*----------------------------------------------------------------*/



static bool bio_writes_complete_block(struct cache *cache, struct bio *bio)
{
	return (bio_data_dir(bio) == WRITE) &&
		(bio->bi_iter.bi_size == (cache->sectors_per_block << SECTOR_SHIFT));
}

Contributors
Person Tokens Prop Commits CommitProp
Joe Thornber 42 100.00% 2 100.00%
Total 42 100.00% 2 100.00%



static bool optimisable_bio(struct cache *cache, struct bio *bio, dm_oblock_t block)
{
	return writeback_mode(&cache->features) &&
		(is_discarded_oblock(cache, block) || bio_writes_complete_block(cache, bio));
}

Contributors
Person Tokens Prop Commits CommitProp
Joe Thornber 44 100.00% 3 100.00%
Total 44 100.00% 3 100.00%



static int map_bio(struct cache *cache, struct bio *bio, dm_oblock_t block,
		   bool *commit_needed)
{
	int r, data_dir;
	bool rb, background_queued;
	dm_cblock_t cblock;
	size_t pb_data_size = get_per_bio_data_size(cache);
	struct per_bio_data *pb = get_per_bio_data(bio, pb_data_size);

	*commit_needed = false;

	rb = bio_detain_shared(cache, block, bio);
	if (!rb) {
		/*
                 * An exclusive lock is held for this block, so we have to
                 * wait.  We set the commit_needed flag so the current
                 * transaction will be committed asap, allowing this lock
                 * to be dropped.
                 */
		*commit_needed = true;
		return DM_MAPIO_SUBMITTED;
	}

	data_dir = bio_data_dir(bio);

	if (optimisable_bio(cache, bio, block)) {
		struct policy_work *op = NULL;

		r = policy_lookup_with_work(cache->policy, block, &cblock, data_dir, true, &op);
		if (unlikely(r && r != -ENOENT)) {
			DMERR_LIMIT("%s: policy_lookup_with_work() failed with r = %d",
				    cache_device_name(cache), r);
			bio_io_error(bio);
			return DM_MAPIO_SUBMITTED;
		}

		if (r == -ENOENT && op) {
			bio_drop_shared_lock(cache, bio);
			BUG_ON(op->op != POLICY_PROMOTE);
			mg_start(cache, op, bio);
			return DM_MAPIO_SUBMITTED;
		}
	} else {
		r = policy_lookup(cache->policy, block, &cblock, data_dir, false, &background_queued);
		if (unlikely(r && r != -ENOENT)) {
			DMERR_LIMIT("%s: policy_lookup() failed with r = %d",
				    cache_device_name(cache), r);
			bio_io_error(bio);
			return DM_MAPIO_SUBMITTED;
		}

		if (background_queued)
			wake_migration_worker(cache);
	}

	if (r == -ENOENT) {
		/*
                 * Miss.
                 */
		inc_miss_counter(cache, bio);
		if (pb->req_nr == 0) {
			accounted_begin(cache, bio);
			remap_to_origin_clear_discard(cache, bio, block);

		} else {
			/*
                         * This is a duplicate writethrough io that is no
                         * longer needed because the block has been demoted.
                         */
			bio_endio(bio);
			return DM_MAPIO_SUBMITTED;
		}
	} else {
		/*
                 * Hit.
                 */
		inc_hit_counter(cache, bio);

		/*
                 * Passthrough always maps to the origin, invalidating any
                 * cache blocks that are written to.
                 */
		if (passthrough_mode(&cache->features)) {
			if (bio_data_dir(bio) == WRITE) {
				bio_drop_shared_lock(cache, bio);
				atomic_inc(&cache->stats.demotion);
				invalidate_start(cache, cblock, block, bio);
			} else
				remap_to_origin_clear_discard(cache, bio, block);

		} else {
			if (bio_data_dir(bio) == WRITE && writethrough_mode(&cache->features) &&
			    !is_dirty(cache, cblock)) {
				remap_to_origin_then_cache(cache, bio, block, cblock);
				accounted_begin(cache, bio);
			} else
				remap_to_cache_dirty(cache, bio, block, cblock);
		}
	}

	/*
         * dm core turns FUA requests into a separate payload and FLUSH req.
         */
	if (bio->bi_opf & REQ_FUA) {
		/*
                 * issue_after_commit will call accounted_begin a second time.  So
                 * we call accounted_complete() to avoid double accounting.
                 */
		accounted_complete(cache, bio);
		issue_after_commit(&cache->committer, bio);
		*commit_needed = true;
		return DM_MAPIO_SUBMITTED;
	}

	return DM_MAPIO_REMAPPED;
}

Contributors
Person Tokens Prop Commits CommitProp
Joe Thornber 492 97.62% 6 60.00%
Mike Snitzer 12 2.38% 4 40.00%
Total 504 100.00% 10 100.00%



static bool process_bio(struct cache *cache, struct bio *bio)
{
	bool commit_needed;

	if (map_bio(cache, bio, get_bio_block(cache, bio), &commit_needed) == DM_MAPIO_REMAPPED)
		generic_make_request(bio);

	return commit_needed;
}

Contributors
Person Tokens Prop Commits CommitProp
Joe Thornber 48 100.00% 2 100.00%
Total 48 100.00% 2 100.00%

/*
 * A non-zero return indicates read_only or fail_io mode.
 */


static int commit(struct cache *cache, bool clean_shutdown)
{
	int r;

	if (get_cache_mode(cache) >= CM_READ_ONLY)
		return -EINVAL;

	atomic_inc(&cache->stats.commit_count);
	r = dm_cache_commit(cache->cmd, clean_shutdown);
	if (r)
		metadata_operation_failed(cache, "dm_cache_commit", r);

	return r;
}

Contributors
Person Tokens Prop Commits CommitProp
Joe Thornber 67 100.00% 4 100.00%
Total 67 100.00% 4 100.00%

/*
 * Used by the batcher.
 */


static blk_status_t commit_op(void *context)
{
	struct cache *cache = context;

	if (dm_cache_changed_this_transaction(cache->cmd))
		return errno_to_blk_status(commit(cache, false));

	return 0;
}

Contributors
Person Tokens Prop Commits CommitProp
Joe Thornber 36 90.00% 4 80.00%
Christoph Hellwig 4 10.00% 1 20.00%
Total 40 100.00% 5 100.00%

/*----------------------------------------------------------------*/



static bool process_flush_bio(struct cache *cache, struct bio *bio)
{
	size_t pb_data_size = get_per_bio_data_size(cache);
	struct per_bio_data *pb = get_per_bio_data(bio, pb_data_size);

	if (!pb->req_nr)
		remap_to_origin(cache, bio);
	else
		remap_to_cache(cache, bio, 0);

	issue_after_commit(&cache->committer, bio);
	return true;
}

Contributors
Person Tokens Prop Commits CommitProp
Joe Thornber 73 100.00% 3 100.00%
Total 73 100.00% 3 100.00%



static bool process_discard_bio(struct cache *cache, struct bio *bio)
{
	dm_dblock_t b, e;

	// FIXME: do we need to lock the region?  Or can we just assume the
	// user wont be so foolish as to issue discard concurrently with
	// other IO?
	calc_discard_block_range(cache, bio, &b, &e);
	while (b != e) {
		set_discard(cache, b);
		b = to_dblock(from_dblock(b) + 1);
	}

	bio_endio(bio);

	return false;
}

Contributors
Person Tokens Prop Commits CommitProp
Joe Thornber 70 97.22% 3 75.00%
Christoph Hellwig 2 2.78% 1 25.00%
Total 72 100.00% 4 100.00%



static void process_deferred_bios(struct work_struct *ws)
{
	struct cache *cache = container_of(ws, struct cache, deferred_bio_worker);

	unsigned long flags;
	bool commit_needed = false;
	struct bio_list bios;
	struct bio *bio;

	bio_list_init(&bios);

	spin_lock_irqsave(&cache->lock, flags);
	bio_list_merge(&bios, &cache->deferred_bios);
	bio_list_init(&cache->deferred_bios);
	spin_unlock_irqrestore(&cache->lock, flags);

	while ((bio = bio_list_pop(&bios))) {
		if (bio->bi_opf & REQ_PREFLUSH)
			commit_needed = process_flush_bio(cache, bio) || commit_needed;

		else if (bio_op(bio) == REQ_OP_DISCARD)
			commit_needed = process_discard_bio(cache, bio) || commit_needed;

		else
			commit_needed = process_bio(cache, bio) || commit_needed;
	}

	if (commit_needed)
		schedule_commit(&cache->committer);
}

Contributors
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Joe Thornber 163 97.60% 4 80.00%
Christoph Hellwig 4 2.40% 1 20.00%
Total 167 100.00% 5 100.00%



static void process_deferred_writethrough_bios(struct work_struct *ws)
{
	struct cache *cache = container_of(ws, struct cache, deferred_writethrough_worker);

	unsigned long flags;
	struct bio_list bios;
	struct bio *bio;

	bio_list_init(&bios);

	spin_lock_irqsave(&cache->lock, flags);
	bio_list_merge(&bios, &cache->deferred_writethrough_bios);
	bio_list_init(&cache->deferred_writethrough_bios);
	spin_unlock_irqrestore(&cache->lock, flags);

	/*
         * These bios have already been through accounted_begin()
         */
	while ((bio = bio_list_pop(&bios)))
		generic_make_request(bio);
}

Contributors
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Joe Thornber 102 100.00% 4 100.00%
Total 102 100.00% 4 100.00%

/*----------------------------------------------------------------
 * Main worker loop
 *--------------------------------------------------------------*/



static void requeue_deferred_bios(struct cache *cache)
{
	struct bio *bio;
	struct bio_list bios;

	bio_list_init(&bios);
	bio_list_merge(&bios, &cache->deferred_bios);
	bio_list_init(&cache->deferred_bios);

	while ((bio = bio_list_pop(&bios))) {
		bio->bi_status = BLK_STS_DM_REQUEUE;
		bio_endio(bio);
	}
}

Contributors
Person Tokens Prop Commits CommitProp
Joe Thornber 68 97.14% 4 80.00%
Christoph Hellwig 2 2.86% 1 20.00%
Total 70 100.00% 5 100.00%

/*
 * We want to commit periodically so that not too much
 * unwritten metadata builds up.
 */


static void do_waker(struct work_struct *ws)
{
	struct cache *cache = container_of(to_delayed_work(ws), struct cache, waker);

	policy_tick(cache->policy, true);
	wake_migration_worker(cache);
	schedule_commit(&cache->committer);
	queue_delayed_work(cache->wq, &cache->waker, COMMIT_PERIOD);
}

Contributors
Person Tokens Prop Commits CommitProp
Joe Thornber 65 100.00% 4 100.00%
Total 65 100.00% 4 100.00%



static void check_migrations(struct work_struct *ws)
{
	int r;
	struct policy_work *op;
	struct cache *cache = container_of(ws, struct cache, migration_worker);
	enum busy b;

	for (;;) {
		b = spare_migration_bandwidth(cache);

		r = policy_get_background_work(cache->policy, b == IDLE, &op);
		if (r == -ENODATA)
			break;

		if (r) {
			DMERR_LIMIT("%s: policy_background_work failed",
				    cache_device_name(cache));
			break;
		}

		r = mg_start(cache, op, NULL);
		if (r)
			break;
	}
}

Contributors
Person Tokens Prop Commits CommitProp
Joe Thornber 109 100.00% 2 100.00%
Total 109 100.00% 2 100.00%

/*----------------------------------------------------------------
 * Target methods
 *--------------------------------------------------------------*/

/*
 * This function gets called on the error paths of the constructor, so we
 * have to cope with a partially initialised struct.
 */


static void destroy(struct cache *cache)
{
	unsigned i;

	mempool_destroy(cache->migration_pool);

	if (cache->prison)
		dm_bio_prison_destroy_v2(cache->prison);

	if (cache->wq)
		destroy_workqueue(cache->wq);

	if (cache->dirty_bitset)
		free_bitset(cache->dirty_bitset);

	if (cache->discard_bitset)
		free_bitset(cache->discard_bitset);

	if (cache->copier)
		dm_kcopyd_client_destroy(cache->copier);

	if (cache->cmd)
		dm_cache_metadata_close(cache->cmd);

	if (cache->metadata_dev)
		dm_put_device(cache->ti, cache->metadata_dev);

	if (cache->origin_dev)
		dm_put_device(cache->ti, cache->origin_dev);

	if (cache->cache_dev)
		dm_put_device(cache->ti, cache->cache_dev);

	if (cache->policy)
		dm_cache_policy_destroy(cache->policy);

	for (i = 0; i < cache->nr_ctr_args ; i++)
		kfree(cache->ctr_args[i]);
	kfree(cache->ctr_args);

	kfree(cache);
}

Contributors
Person Tokens Prop Commits CommitProp
Joe Thornber 200 100.00% 2 100.00%
Total 200 100.00% 2 100.00%



static void cache_dtr(struct dm_target *ti)
{
	struct cache *cache = ti->private;

	destroy(cache);
}

Contributors
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Joe Thornber 25 100.00% 1 100.00%
Total 25 100.00% 1 100.00%



static sector_t get_dev_size(struct dm_dev *dev)
{
	return i_size_read(dev->bdev->bd_inode) >> SECTOR_SHIFT;
}

Contributors
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Joe Thornber 23 100.00% 1 100.00%
Total 23 100.00% 1 100.00%

/*----------------------------------------------------------------*/

/*
 * Construct a cache device mapping.
 *
 * cache <metadata dev> <cache dev> <origin dev> <block size>
 *       <#feature args> [<feature arg>]*
 *       <policy> <#policy args> [<policy arg>]*
 *
 * metadata dev    : fast device holding the persistent metadata
 * cache dev       : fast device holding cached data blocks
 * origin dev      : slow device holding original data blocks
 * block size      : cache unit size in sectors
 *
 * #feature args   : number of feature arguments passed
 * feature args    : writethrough.  (The default is writeback.)
 *
 * policy          : the replacement policy to use
 * #policy args    : an even number of policy arguments corresponding
 *                   to key/value pairs passed to the policy
 * policy args     : key/value pairs passed to the policy
 *                   E.g. 'sequential_threshold 1024'
 *                   See cache-policies.txt for details.
 *
 * Optional feature arguments are:
 *   writethrough  : write through caching that prohibits cache block
 *                   content from being different from origin block content.
 *                   Without this argument, the default behaviour is to write
 *                   back cache block contents later for performance reasons,
 *                   so they may differ from the corresponding origin blocks.
 */

struct cache_args {
	
struct dm_target *ti;

	
struct dm_dev *metadata_dev;

	
struct dm_dev *cache_dev;
	
sector_t cache_sectors;

	
struct dm_dev *origin_dev;
	
sector_t origin_sectors;

	
uint32_t block_size;

	
const char *policy_name;
	
int policy_argc;
	
const char **policy_argv;

	
struct cache_features features;
};



static void destroy_cache_args(struct cache_args *ca)
{
	if (ca->metadata_dev)
		dm_put_device(ca->ti, ca->metadata_dev);

	if (ca->cache_dev)
		dm_put_device(ca->ti, ca->cache_dev);

	if (ca->origin_dev)
		dm_put_device(ca->ti, ca->origin_dev);

	kfree(ca);
}

Contributors
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Joe Thornber 67 100.00% 1 100.00%
Total 67 100.00% 1 100.00%



static bool at_least_one_arg(struct dm_arg_set *as, char **error)
{
	if (!as->argc) {
		*error = "Insufficient args";
		return false;
	}

	return true;
}

Contributors
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Joe Thornber 36 100.00% 1 100.00%
Total 36 100.00% 1 100.00%



static int parse_metadata_dev(struct cache_args *ca, struct dm_arg_set *as,
			      char **error)
{
	int r;
	sector_t metadata_dev_size;
	char b[BDEVNAME_SIZE];

	if (!at_least_one_arg(as, error))
		return -EINVAL;

	r = dm_get_device(ca->ti, dm_shift_arg(as), FMODE_READ | FMODE_WRITE,
			  &ca->metadata_dev);
	if (r) {
		*error = "Error opening metadata device";
		return r;
	}

	metadata_dev_size = get_dev_size(ca->metadata_dev);
	if (metadata_dev_size > DM_CACHE_METADATA_MAX_SECTORS_WARNING)
		DMWARN("Metadata device %s is larger than %u sectors: excess space will not be used.",
		       bdevname(ca->metadata_dev->bdev, b), THIN_METADATA_MAX_SECTORS);

	return 0;
}

Contributors
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Joe Thornber 120 100.00% 1 100.00%
Total 120 100.00% 1 100.00%



static int parse_cache_dev(struct cache_args *ca, struct dm_arg_set *as,
			   char **error)
{
	int r;

	if (!at_least_one_arg(as, error))
		return -EINVAL;

	r = dm_get_device(ca->ti, dm_shift_arg(as), FMODE_READ | FMODE_WRITE,
			  &ca->cache_dev);
	if (r) {
		*error = "Error opening cache device";
		return r;
	}
	ca->cache_sectors = get_dev_size(ca->cache_dev);

	return 0;
}

Contributors
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Joe Thornber 89 100.00% 1 100.00%
Total 89 100.00% 1 100.00%



static int parse_origin_dev(struct cache_args *ca, struct dm_arg_set *as,
			    char **error)
{
	int r;

	if (!at_least_one_arg(as, error))
		return -EINVAL;

	r = dm_get_device(ca->ti, dm_shift_arg(as), FMODE_READ | FMODE_WRITE,
			  &ca->origin_dev);
	if (r) {
		*error = "Error opening origin device";
		return r;
	}

	ca->origin_sectors = get_dev_size(ca->origin_dev);
	if (ca->ti->len > ca->origin_sectors) {
		*error = "Device size larger than cached device";
		return -EINVAL;
	}

	return 0;
}

Contributors
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Joe Thornber 112 100.00% 1 100.00%
Total 112 100.00% 1 100.00%



static int parse_block_size(struct cache_args *ca, struct dm_arg_set *as,
			    char **error)
{
	unsigned long block_size;

	if (!at_least_one_arg(as, error))
		return -EINVAL;

	if (kstrtoul(dm_shift_arg(as), 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)) {
		*error = "Invalid data block size";
		return -EINVAL;
	}

	if (block_size > ca->cache_sectors) {
		*error = "Data block size is larger than the cache device";
		return -EINVAL;
	}

	ca->block_size = block_size;

	return 0;
}

Contributors
Person Tokens Prop Commits CommitProp
Joe Thornber 101 90.18% 1 50.00%
Mike Snitzer 11 9.82% 1 50.00%
Total 112 100.00% 2 100.00%



static void init_features(struct cache_features *cf)
{
	cf->mode = CM_WRITE;
	cf->io_mode = CM_IO_WRITEBACK;
	cf->metadata_version = 1;
}

Contributors
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Joe Thornber 29 100.00% 3 100.00%
Total 29 100.00% 3 100.00%



static int parse_features(struct cache_args *ca, struct dm_arg_set *as,
			  char **error)
{
	static const struct dm_arg _args[] = {
		{0, 2, "Invalid number of cache feature arguments"},
        };

	int r;
	unsigned argc;
	const char *arg;
	struct cache_features *cf = &ca->features;

	init_features(cf);

	r = dm_read_arg_group(_args, as, &argc, error);
	if (r)
		return -EINVAL;

	while (argc--) {
		arg = dm_shift_arg(as);

		if (!strcasecmp(arg, "writeback"))
			cf->io_mode = CM_IO_WRITEBACK;

		else if (!strcasecmp(arg, "writethrough"))
			cf->io_mode = CM_IO_WRITETHROUGH;

		else if (!strcasecmp(arg, "passthrough"))
			cf->io_mode = CM_IO_PASSTHROUGH;

		else if (!strcasecmp(arg, "metadata2"))
			cf->metadata_version = 2;

		else {
			*error = "Unrecognised cache feature requested";
			return -EINVAL;
		}
	}

	return 0;
}

Contributors
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Joe Thornber 181 99.45% 3 75.00%
Eric Biggers 1 0.55% 1 25.00%
Total 182 100.00% 4 100.00%



static int parse_policy(struct cache_args *ca, struct dm_arg_set *as,
			char **error)
{
	static const struct dm_arg _args[] = {
		{0, 1024, "Invalid number of policy arguments"},
        };

	int r;

	if (!at_least_one_arg(as, error))
		return -EINVAL;

	ca->policy_name = dm_shift_arg(as);

	r = dm_read_arg_group(_args, as, &ca->policy_argc, error);
	if (r)
		return -EINVAL;

	ca->policy_argv = (const char **)as->argv;
	dm_consume_args(as, ca->policy_argc);

	return 0;
}

Contributors
Person Tokens Prop Commits CommitProp
Joe Thornber 113 99.12% 1 50.00%
Eric Biggers 1 0.88% 1 50.00%
Total 114 100.00% 2 100.00%



static int parse_cache_args(struct cache_args *ca, int argc, char **argv,
			    char **error)
{
	int r;
	struct dm_arg_set as;

	as.argc = argc;
	as.argv = argv;

	r = parse_metadata_dev(ca, &as, error);
	if (r)
		return r;

	r = parse_cache_dev(ca, &as, error);
	if (r)
		return r;

	r = parse_origin_dev(ca, &as, error);
	if (r)
		return r;

	r = parse_block_size(ca, &as, error);
	if (r)
		return r;

	r = parse_features(ca, &as, error);
	if (r)
		return r;

	r = parse_policy(ca, &as, error);
	if (r)
		return r;

	return 0;
}

Contributors
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Joe Thornber 160 100.00% 1 100.00%
Total 160 100.00% 1 100.00%

/*----------------------------------------------------------------*/


static struct kmem_cache *migration_cache;


#define NOT_CORE_OPTION 1



static int process_config_option(struct cache *cache, const char *key, const char *value)
{
	unsigned long tmp;

	if (!strcasecmp(key, "migration_threshold")) {
		if (kstrtoul(value, 10, &tmp))
			return -EINVAL;

		cache->migration_threshold = tmp;
		return 0;
	}

	return NOT_CORE_OPTION;
}

Contributors
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Alasdair G. Kergon 57 87.69% 1 50.00%
Joe Thornber 8 12.31% 1 50.00%
Total 65 100.00% 2 100.00%



static int set_config_value(struct cache *cache, const char *key, const char *value)
{
	int r = process_config_option(cache, key, value);

	if (r == NOT_CORE_OPTION)
		r = policy_set_config_value(cache->policy, key, value);

	if (r)
		DMWARN("bad config value for %s: %s", key, value);

	return r;
}

Contributors
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Joe Thornber 68 100.00% 1 100.00%
Total 68 100.00% 1 100.00%



static int set_config_values(struct cache *cache, int argc, const char **argv)
{
	int r = 0;

	if (argc & 1) {
		DMWARN("Odd number of policy arguments given but they should be <key> <value> pairs.");
		return -EINVAL;
	}

	while (argc) {
		r = set_config_value(cache, argv[0], argv[1]);
		if (r)
			break;

		argc -= 2;
		argv += 2;
	}

	return r;
}

Contributors
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Joe Thornber 81 100.00% 2 100.00%
Total 81 100.00% 2 100.00%



static int create_cache_policy(struct cache *cache, struct cache_args *ca,
			       char **error)
{
	struct dm_cache_policy *p = dm_cache_policy_create(ca->policy_name,
							   cache->cache_size,
							   cache->origin_sectors,
							   cache->sectors_per_block);
	if (IS_ERR(p)) {
		*error = "Error creating cache's policy";
		return PTR_ERR(p);
	}
	cache->policy = p;
	BUG_ON(!cache->policy);

	return 0;
}

Contributors
Person Tokens Prop Commits CommitProp
Joe Thornber 62 75.61% 3 75.00%
Mikulas Patocka 20 24.39% 1 25.00%
Total 82 100.00% 4 100.00%

/*
 * We want the discard block size to be at least the size of the cache
 * block size and have no more than 2^14 discard blocks across the origin.
 */

#define MAX_DISCARD_BLOCKS (1 << 14)



static bool too_many_discard_blocks(sector_t discard_block_size,
				    sector_t origin_size)
{
	(void) sector_div(origin_size, discard_block_size);

	return origin_size > MAX_DISCARD_BLOCKS;
}

Contributors
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Joe Thornber 27 100.00% 1 100.00%
Total 27 100.00% 1 100.00%



static sector_t calculate_discard_block_size(sector_t cache_block_size,
					     sector_t origin_size)
{
	sector_t discard_block_size = cache_block_size;

	if (origin_size)
		while (too_many_discard_blocks(discard_block_size, origin_size))
			discard_block_size *= 2;

	return discard_block_size;
}

Contributors
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Joe Thornber 37 100.00% 2 100.00%
Total 37 100.00% 2 100.00%



static void set_cache_size(struct cache *cache, dm_cblock_t size)
{
	dm_block_t nr_blocks = from_cblock(size);

	if (nr_blocks > (1 << 20) && cache->cache_size != size)
		DMWARN_LIMIT("You have created a cache device with a lot of individual cache blocks (%llu)\n"
			     "All these mappings can consume a lot of kernel memory, and take some time to read/write.\n"
			     "Please consider increasing the cache block size to reduce the overall cache block count.",
			     (unsigned long long) nr_blocks);

	cache->cache_size = size;
}

Contributors
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Joe Thornber 58 100.00% 1 100.00%
Total 58 100.00% 1 100.00%



static int is_congested(struct dm_dev *dev, int bdi_bits)
{
	struct request_queue *q = bdev_get_queue(dev->bdev);
	return bdi_congested(q->backing_dev_info, bdi_bits);
}

Contributors
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Joe Thornber 36 100.00% 3 100.00%
Total 36 100.00% 3 100.00%



static int cache_is_congested(struct dm_target_callbacks *cb, int bdi_bits)
{
	struct cache *cache = container_of(cb, struct cache, callbacks);

	return is_congested(cache->origin_dev, bdi_bits) ||
		is_congested(cache->cache_dev, bdi_bits);
}

Contributors
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Joe Thornber 48 100.00% 3 100.00%
Total 48 100.00% 3 100.00%


#define DEFAULT_MIGRATION_THRESHOLD 2048



static int cache_create(struct cache_args *ca, struct cache **result)
{
	int r = 0;
	char **error = &ca->ti->error;
	struct cache *cache;
	struct dm_target *ti = ca->ti;
	dm_block_t origin_blocks;
	struct dm_cache_metadata *cmd;
	bool may_format = ca->features.mode == CM_WRITE;

	cache = kzalloc(sizeof(*cache), GFP_KERNEL);
	if (!cache)
		return -ENOMEM;

	cache->ti = ca->ti;
	ti->private = cache;
	ti->num_flush_bios = 2;
	ti->flush_supported = true;

	ti->num_discard_bios = 1;
	ti->discards_supported = true;
	ti->split_discard_bios = false;

	cache->features = ca->features;
	ti->per_io_data_size = get_per_bio_data_size(cache);

	cache->callbacks.congested_fn = cache_is_congested;
	dm_table_add_target_callbacks(ti->table, &cache->callbacks);

	cache->metadata_dev = ca->metadata_dev;
	cache->origin_dev = ca->origin_dev;
	cache->cache_dev = ca->cache_dev;

	ca->metadata_dev = ca->origin_dev = ca->cache_dev = NULL;

	origin_blocks = cache->origin_sectors = ca->origin_sectors;
	origin_blocks = block_div(origin_blocks, ca->block_size);
	cache->origin_blocks = to_oblock(origin_blocks);

	cache->sectors_per_block = ca->block_size;
	if (dm_set_target_max_io_len(ti, cache->sectors_per_block)) {
		r = -EINVAL;
		goto bad;
	}

	if (ca->block_size & (ca->block_size - 1)) {
		dm_block_t cache_size = ca->cache_sectors;

		cache->sectors_per_block_shift = -1;
		cache_size = block_div(cache_size, ca->block_size);
		set_cache_size(cache, to_cblock(cache_size));
	} else {
		cache->sectors_per_block_shift = __ffs(ca->block_size);
		set_cache_size(cache, to_cblock(ca->cache_sectors >> cache->sectors_per_block_shift));
	}

	r = create_cache_policy(cache, ca, error);
	if (r)
		goto bad;

	cache->policy_nr_args = ca->policy_argc;
	cache->migration_threshold = DEFAULT_MIGRATION_THRESHOLD;

	r = set_config_values(cache, ca->policy_argc, ca->policy_argv);
	if (r) {
		*error = "Error setting cache policy's config values";
		goto bad;
	}

	cmd = dm_cache_metadata_open(cache->metadata_dev->bdev,
				     ca->block_size, may_format,
				     dm_cache_policy_get_hint_size(cache->policy),
				     ca->features.metadata_version);
	if (IS_ERR(cmd)) {
		*error = "Error creating metadata object";
		r = PTR_ERR(cmd);
		goto bad;
	}
	cache->cmd = cmd;
	set_cache_mode(cache, CM_WRITE);
	if (get_cache_mode(cache) != CM_WRITE) {
		*error = "Unable to get write access to metadata, please check/repair metadata.";
		r = -EINVAL;
		goto bad;
	}

	if (passthrough_mode(&cache->features)) {
		bool all_clean;

		r = dm_cache_metadata_all_clean(cache->cmd, &all_clean);
		if (r) {
			*error = "dm_cache_metadata_all_clean() failed";
			goto bad;
		}

		if (!all_clean) {
			*error = "Cannot enter passthrough mode unless all blocks are clean";
			r = -EINVAL;
			goto bad;
		}

		policy_allow_migrations(cache->policy, false);
	}

	spin_lock_init(&cache->lock);
	INIT_LIST_HEAD(&cache->deferred_cells);
	bio_list_init(&cache->deferred_bios);
	bio_list_init(&cache->deferred_writethrough_bios);
	atomic_set(&cache->nr_allocated_migrations, 0);
	atomic_set(&cache->nr_io_migrations, 0);
	init_waitqueue_head(&cache->migration_wait);

	r = -ENOMEM;
	atomic_set(&cache->nr_dirty, 0);
	cache->dirty_bitset = alloc_bitset(from_cblock(cache->cache_size));
	if (!cache->dirty_bitset) {
		*error = "could not allocate dirty bitset";
		goto bad;
	}
	clear_bitset(cache->dirty_bitset, from_cblock(cache->cache_size));

	cache->discard_block_size =
		calculate_discard_block_size(cache->sectors_per_block,
					     cache->origin_sectors);
	cache->discard_nr_blocks = to_dblock(dm_sector_div_up(cache->origin_sectors,
							      cache->discard_block_size));
	cache->discard_bitset = alloc_bitset(from_dblock(cache->discard_nr_blocks));
	if (!cache->discard_bitset) {
		*error = "could not allocate discard bitset";
		goto bad;
	}
	clear_bitset(cache->discard_bitset, from_dblock(cache->discard_nr_blocks));

	cache->copier = dm_kcopyd_client_create(&dm_kcopyd_throttle);
	if (IS_ERR(cache->copier)) {
		*error = "could not create kcopyd client";
		r = PTR_ERR(cache->copier);
		goto bad;
	}

	cache->wq = alloc_workqueue("dm-" DM_MSG_PREFIX, WQ_MEM_RECLAIM, 0);
	if (!cache->wq) {
		*error = "could not create workqueue for metadata object";
		goto bad;
	}
	INIT_WORK(&cache->deferred_bio_worker, process_deferred_bios);
	INIT_WORK(&cache->deferred_writethrough_worker,
		  process_deferred_writethrough_bios);
	INIT_WORK(&cache->migration_worker, check_migrations);
	INIT_DELAYED_WORK(&cache->waker, do_waker);

	cache->prison = dm_bio_prison_create_v2(cache->wq);
	if (!cache->prison) {
		*error = "could not create bio prison";
		goto bad;
	}

	cache->migration_pool = mempool_create_slab_pool(MIGRATION_POOL_SIZE,
							 migration_cache);
	if (!cache->migration_pool) {
		*error = "Error creating cache's migration mempool";
		goto bad;
	}

	cache->need_tick_bio = true;
	cache->sized = false;
	cache->invalidate = false;
	cache->commit_requested = false;
	cache->loaded_mappings = false;
	cache->loaded_discards = false;

	load_stats(cache);

	atomic_set(&cache->stats.demotion, 0);
	atomic_set(&cache->stats.promotion, 0);
	atomic_set(&cache->stats.copies_avoided, 0);
	atomic_set(&cache->stats.cache_cell_clash, 0);
	atomic_set(&cache->stats.commit_count, 0);
	atomic_set(&cache->stats.discard_count, 0);

	spin_lock_init(&cache->invalidation_lock);
	INIT_LIST_HEAD(&cache->invalidation_requests);

	batcher_init(&cache->committer, commit_op, cache,
		     issue_op, cache, cache->wq);
	iot_init(&cache->tracker);

	init_rwsem(&cache->background_work_lock);
	prevent_background_work(cache);

	*result = cache;
	return 0;
bad:
	destroy(cache);
	return r;
}

Contributors
Person Tokens Prop Commits CommitProp
Joe Thornber 1099 98.04% 18 78.26%
Mike Snitzer 9 0.80% 2 8.70%
Anssi Hannula 5 0.45% 1 4.35%
Wei Yongjun 5 0.45% 1 4.35%
Heinz Mauelshagen 3 0.27% 1 4.35%
Total 1121 100.00% 23 100.00%



static int copy_ctr_args(struct cache *cache, int argc, const char **argv)
{
	unsigned i;
	const char **copy;

	copy = kcalloc(argc, sizeof(*copy), GFP_KERNEL);
	if (!copy)
		return -ENOMEM;
	for (i = 0; i < argc; i++) {
		copy[i] = kstrdup(argv[i], GFP_KERNEL);
		if (!copy[i]) {
			while (i--)
				kfree(copy[i]);
			kfree(copy);
			return -ENOMEM;
		}
	}

	cache->nr_ctr_args = argc;
	cache->ctr_args = copy;

	return 0;
}

Contributors
Person Tokens Prop Commits CommitProp
Joe Thornber 130 100.00% 6 100.00%
Total 130 100.00% 6 100.00%



static int cache_ctr(struct dm_target *ti, unsigned argc, char **argv)
{
	int r = -EINVAL;
	struct cache_args *ca;
	struct cache *cache = NULL;

	ca = kzalloc(sizeof(*ca), GFP_KERNEL);
	if (!ca) {
		ti->error = "Error allocating memory for cache";
		return -ENOMEM;
	}
	ca->ti = ti;

	r = parse_cache_args(ca, argc, argv, &ti->error);
	if (r)
		goto out;

	r = cache_create(ca, &cache);
	if (r)
		goto out;

	r = copy_ctr_args(cache, argc - 3, (const char **)argv + 3);
	if (r) {
		destroy(cache);
		goto out;
	}

	ti->private = cache;
out:
	destroy_cache_args(ca);
	return r;
}

Contributors
Person Tokens Prop Commits CommitProp
Joe Thornber 163 99.39% 7 87.50%
Mike Snitzer 1 0.61% 1 12.50%
Total 164 100.00% 8 100.00%

/*----------------------------------------------------------------*/



static int cache_map(struct dm_target *ti, struct bio *bio)
{
	struct cache *cache = ti->private;

	int r;
	bool commit_needed;
	dm_oblock_t block = get_bio_block(cache, bio);
	size_t pb_data_size = get_per_bio_data_size(cache);

	init_per_bio_data(bio, pb_data_size);
	if (unlikely(from_oblock(block) >= from_oblock(cache->origin_blocks))) {
		/*
                 * This can only occur if the io goes to a partial block at
                 * the end of the origin device.  We don't cache these.
                 * Just remap to the origin and carry on.
                 */
		remap_to_origin(cache, bio);
		accounted_begin(cache, bio);
		return DM_MAPIO_REMAPPED;
	}

	if (discard_or_flush(bio)) {
		defer_bio(cache, bio);
		return DM_MAPIO_SUBMITTED;
	}

	r = map_bio(cache, bio, block, &commit_needed);
	if (commit_needed)
		schedule_commit(&cache->committer);

	return r;
}

Contributors
Person Tokens Prop Commits CommitProp
Joe Thornber 139 98.58% 5 83.33%
Mike Snitzer 2 1.42% 1 16.67%
Total 141 100.00% 6 100.00%



static int cache_end_io(struct dm_target *ti, struct bio *bio,
		blk_status_t *error)
{
	struct cache *cache = ti->private;
	unsigned long flags;
	size_t pb_data_size = get_per_bio_data_size(cache);
	struct per_bio_data *pb = get_per_bio_data(bio, pb_data_size);

	if (pb->tick) {
		policy_tick(cache->policy, false);

		spin_lock_irqsave(&cache->lock, flags);
		cache->need_tick_bio = true;
		spin_unlock_irqrestore(&cache->lock, flags);
	}

	bio_drop_shared_lock(cache, bio);
	accounted_complete(cache, bio);

	return DM_ENDIO_DONE;
}

Contributors
Person Tokens Prop Commits CommitProp
Joe Thornber 100 88.50% 4 57.14%
Mike Snitzer 10 8.85% 1 14.29%
Christoph Hellwig 3 2.65% 2 28.57%
Total 113 100.00% 7 100.00%



static int write_dirty_bitset(struct cache *cache)
{
	int r;

	if (get_cache_mode(cache) >= CM_READ_ONLY)
		return -EINVAL;

	r = dm_cache_set_dirty_bits(cache->cmd, from_cblock(cache->cache_size), cache->dirty_bitset);
	if (r)
		metadata_operation_failed(cache, "dm_cache_set_dirty_bits", r);

	return r;
}

Contributors
Person Tokens Prop Commits CommitProp
Joe Thornber 63 100.00% 3 100.00%
Total 63 100.00% 3 100.00%



static int write_discard_bitset(struct cache *cache)
{
	unsigned i, r;

	if (get_cache_mode(cache) >= CM_READ_ONLY)
		return -EINVAL;

	r = dm_cache_discard_bitset_resize(cache->cmd, cache->discard_block_size,
					   cache->discard_nr_blocks);
	if (r) {
		DMERR("%s: could not resize on-disk discard bitset", cache_device_name(cache));
		metadata_operation_failed(cache, "dm_cache_discard_bitset_resize", r);
		return r;
	}

	for (i = 0; i < from_dblock(cache->discard_nr_blocks); i++) {
		r = dm_cache_set_discard(cache->cmd, to_dblock(i),
					 is_discarded(cache, to_dblock(i)));
		if (r) {
			metadata_operation_failed(cache, "dm_cache_set_discard", r);
			return r;
		}
	}

	return 0;
}

Contributors
Person Tokens Prop Commits CommitProp
Joe Thornber 133 95.68% 3 75.00%
Mike Snitzer 6 4.32% 1 25.00%
Total 139 100.00% 4 100.00%



static int write_hints(struct cache *cache)
{
	int r;

	if (get_cache_mode(cache) >= CM_READ_ONLY)
		return -EINVAL;

	r = dm_cache_write_hints(cache->cmd, cache->policy);
	if (r) {
		metadata_operation_failed(cache, "dm_cache_write_hints", r);
		return r;
	}

	return 0;
}

Contributors
Person Tokens Prop Commits CommitProp
Joe Thornber 61 100.00% 2 100.00%
Total 61 100.00% 2 100.00%

/*
 * returns true on success
 */


static bool sync_metadata(struct cache *cache)
{
	int r1, r2, r3, r4;

	r1 = write_dirty_bitset(cache);
	if (r1)
		DMERR("%s: could not write dirty bitset", cache_device_name(cache));

	r2 = write_discard_bitset(cache);
	if (r2)
		DMERR("%s: could not write discard bitset", cache_device_name(cache));

	save_stats(cache);

	r3 = write_hints(cache);
	if (r3)
		DMERR("%s: could not write hints", cache_device_name(cache));

	/*
         * If writing the above metadata failed, we still commit, but don't
         * set the clean shutdown flag.  This will effectively force every
         * dirty bit to be set on reload.
         */
	r4 = commit(cache, !r1 && !r2 && !r3);
	if (r4)
		DMERR("%s: could not write cache metadata", cache_device_name(cache));

	return !r1 && !r2 && !r3 && !r4;
}

Contributors
Person Tokens Prop Commits CommitProp
Joe Thornber 108 81.82% 2 66.67%
Mike Snitzer 24 18.18% 1 33.33%
Total 132 100.00% 3 100.00%



static void cache_postsuspend(struct dm_target *ti)
{
	struct cache *cache = ti->private;

	prevent_background_work(cache);
	BUG_ON(atomic_read(&cache->nr_io_migrations));

	cancel_delayed_work(&cache->waker);
	flush_workqueue(cache->wq);
	WARN_ON(cache->tracker.in_flight);

	/*
         * If it's a flush suspend there won't be any deferred bios, so this
         * call is harmless.
         */
	requeue_deferred_bios(cache);

	if (get_cache_mode(cache) == CM_WRITE)
		(void) sync_metadata(cache);
}

Contributors
Person Tokens Prop Commits CommitProp
Joe Thornber 83 100.00% 5 100.00%
Total 83 100.00% 5 100.00%



static int load_mapping(void *context, dm_oblock_t oblock, dm_cblock_t cblock,
			bool dirty, uint32_t hint, bool hint_valid)
{
	int r;
	struct cache *cache = context;

	if (dirty) {
		set_bit(from_cblock(cblock), cache->dirty_bitset);
		atomic_inc(&cache->nr_dirty);
	} else
		clear_bit(from_cblock(cblock), cache->dirty_bitset);

	r = policy_load_mapping(cache->policy, oblock, cblock, dirty, hint, hint_valid);
	if (r)
		return r;

	return 0;
}

Contributors
Person Tokens Prop Commits CommitProp
Joe Thornber 103 100.00% 3 100.00%
Total 103 100.00% 3 100.00%

/*
 * The discard block size in the on disk metadata is not
 * neccessarily the same as we're currently using.  So we have to
 * be careful to only set the discarded attribute if we know it
 * covers a complete block of the new size.
 */

struct discard_load_info {
	
struct cache *cache;

	/*
         * These blocks are sized using the on disk dblock size, rather
         * than the current one.
         */
	
dm_block_t block_size;
	

dm_block_t discard_begin, discard_end;
};



static void discard_load_info_init(struct cache *cache,
				   struct discard_load_info *li)
{
	li->cache = cache;
	li->discard_begin = li->discard_end = 0;
}

Contributors
Person Tokens Prop Commits CommitProp
Joe Thornber 32 100.00% 1 100.00%
Total 32 100.00% 1 100.00%



static void set_discard_range(struct discard_load_info *li)
{
	sector_t b, e;

	if (li->discard_begin == li->discard_end)
		return;

	/*
         * Convert to sectors.
         */
	b = li->discard_begin * li->block_size;
	e = li->discard_end * li->block_size;

	/*
         * Then convert back to the current dblock size.
         */
	b = dm_sector_div_up(b, li->cache->discard_block_size);
	sector_div(e, li->cache->discard_block_size);

	/*
         * The origin may have shrunk, so we need to check we're still in
         * bounds.
         */
	if (e > from_dblock(li->cache->discard_nr_blocks))
		e = from_dblock(li->cache->discard_nr_blocks);

	for (; b < e; b++)
		set_discard(li->cache, to_dblock(b));
}

Contributors
Person Tokens Prop Commits CommitProp
Joe Thornber 120 100.00% 1 100.00%
Total 120 100.00% 1 100.00%



static int load_discard(void *context, sector_t discard_block_size,
			dm_dblock_t dblock, bool discard)
{
	struct discard_load_info *li = context;

	li->block_size = discard_block_size;

	if (discard) {
		if (from_dblock(dblock) == li->discard_end)
			/*
                         * We're already in a discard range, just extend it.
                         */
			li->discard_end = li->discard_end + 1ULL;

		else {
			/*
                         * Emit the old range and start a new one.
                         */
			set_discard_range(li);
			li->discard_begin = from_dblock(dblock);
			li->discard_end = li->discard_begin + 1ULL;
		}
	} else {
		set_discard_range(li);
		li->discard_begin = li->discard_end = 0;
	}

	return 0;
}

Contributors
Person Tokens Prop Commits CommitProp
Joe Thornber 109 100.00% 3 100.00%
Total 109 100.00% 3 100.00%



static dm_cblock_t get_cache_dev_size(struct cache *cache)
{
	sector_t size = get_dev_size(cache->cache_dev);
	(void) sector_div(size, cache->sectors_per_block);
	return to_cblock(size);
}

Contributors
Person Tokens Prop Commits CommitProp
Joe Thornber 39 100.00% 2 100.00%
Total 39 100.00% 2 100.00%



static bool can_resize(struct cache *cache, dm_cblock_t new_size)
{
	if (from_cblock(new_size) > from_cblock(cache->cache_size))
		return true;

	/*
         * We can't drop a dirty block when shrinking the cache.
         */
	while (from_cblock(new_size) < from_cblock(cache->cache_size)) {
		new_size = to_cblock(from_cblock(new_size) + 1);
		if (is_dirty(cache, new_size)) {
			DMERR("%s: unable to shrink cache; cache block %llu is dirty",
			      cache_device_name(cache),
			      (unsigned long long) from_cblock(new_size));
			return false;
		}
	}

	return true;
}

Contributors
Person Tokens Prop Commits CommitProp
Joe Thornber 91 93.81% 2 66.67%
Mike Snitzer 6 6.19% 1 33.33%
Total 97 100.00% 3 100.00%



static int resize_cache_dev(struct cache *cache, dm_cblock_t new_size)
{
	int r;

	r = dm_cache_resize(cache->cmd, new_size);
	if (r) {
		DMERR("%s: could not resize cache metadata", cache_device_name(cache));
		metadata_operation_failed(cache, "dm_cache_resize", r);
		return r;
	}

	set_cache_size(cache, new_size);

	return 0;
}

Contributors
Person Tokens Prop Commits CommitProp
Joe Thornber 59 89.39% 4 66.67%
Mike Snitzer 6 9.09% 1 16.67%
Vincent Pelletier 1 1.52% 1 16.67%
Total 66 100.00% 6 100.00%



static int cache_preresume(struct dm_target *ti)
{
	int r = 0;
	struct cache *cache = ti->private;
	dm_cblock_t csize = get_cache_dev_size(cache);

	/*
         * Check to see if the cache has resized.
         */
	if (!cache->sized) {
		r = resize_cache_dev(cache, csize);
		if (r)
			return r;

		cache->sized = true;

	} else if (csize != cache->cache_size) {
		if (!can_resize(cache, csize))
			return -EINVAL;

		r = resize_cache_dev(cache, csize);
		if (r)
			return r;
	}

	if (!cache->loaded_mappings) {
		r = dm_cache_load_mappings(cache->cmd, cache->policy,
					   load_mapping, cache);
		if (r) {
			DMERR("%s: could not load cache mappings", cache_device_name(cache));
			metadata_operation_failed(cache, "dm_cache_load_mappings", r);
			return r;
		}

		cache->loaded_mappings = true;
	}

	if (!cache->loaded_discards) {
		struct discard_load_info li;

		/*
                 * The discard bitset could have been resized, or the
                 * discard block size changed.  To be safe we start by
                 * setting every dblock to not discarded.
                 */
		clear_bitset(cache->discard_bitset, from_dblock(cache->discard_nr_blocks));

		discard_load_info_init(cache, &li);
		r = dm_cache_load_discards(cache->cmd, load_discard, &li);
		if (r) {
			DMERR("%s: could not load origin discards", cache_device_name(cache));
			metadata_operation_failed(cache, "dm_cache_load_discards", r);
			return r;
		}
		set_discard_range(&li);

		cache->loaded_discards = true;
	}

	return r;
}

Contributors
Person Tokens Prop Commits CommitProp
Joe Thornber 247 95.37% 4 80.00%
Mike Snitzer 12 4.63% 1 20.00%
Total 259 100.00% 5 100.00%



static void cache_resume(struct dm_target *ti)
{
	struct cache *cache = ti->private;

	cache->need_tick_bio = true;
	allow_background_work(cache);
	do_waker(&cache->waker.work);
}

Contributors
Person Tokens Prop Commits CommitProp
Joe Thornber 41 100.00% 2 100.00%
Total 41 100.00% 2 100.00%

/*
 * Status format:
 *
 * <metadata block size> <#used metadata blocks>/<#total metadata blocks>
 * <cache block size> <#used cache blocks>/<#total cache blocks>
 * <#read hits> <#read misses> <#write hits> <#write misses>
 * <#demotions> <#promotions> <#dirty>
 * <#features> <features>*
 * <#core args> <core args>
 * <policy name> <#policy args> <policy args>* <cache metadata mode> <needs_check>
 */


static void cache_status(struct dm_target *ti, status_type_t type,
			 unsigned status_flags, char *result, unsigned maxlen)
{
	int r = 0;
	unsigned i;
	ssize_t sz = 0;
	dm_block_t nr_free_blocks_metadata = 0;
	dm_block_t nr_blocks_metadata = 0;
	char buf[BDEVNAME_SIZE];
	struct cache *cache = ti->private;
	dm_cblock_t residency;
	bool needs_check;

	switch (type) {
	case STATUSTYPE_INFO:
		if (get_cache_mode(cache) == CM_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(cache, false);

		r = dm_cache_get_free_metadata_block_count(cache->cmd, &nr_free_blocks_metadata);
		if (r) {
			DMERR("%s: dm_cache_get_free_metadata_block_count returned %d",
			      cache_device_name(cache), r);
			goto err;
		}

		r = dm_cache_get_metadata_dev_size(cache->cmd, &nr_blocks_metadata);
		if (r) {
			DMERR("%s: dm_cache_get_metadata_dev_size returned %d",
			      cache_device_name(cache), r);
			goto err;
		}

		residency = policy_residency(cache->policy);

		DMEMIT("%u %llu/%llu %llu %llu/%llu %u %u %u %u %u %u %lu ",
		       (unsigned)DM_CACHE_METADATA_BLOCK_SIZE,
		       (unsigned long long)(nr_blocks_metadata - nr_free_blocks_metadata),
		       (unsigned long long)nr_blocks_metadata,
		       (unsigned long long)cache->sectors_per_block,
		       (unsigned long long) from_cblock(residency),
		       (unsigned long long) from_cblock(cache->cache_size),
		       (unsigned) atomic_read(&cache->stats.read_hit),
		       (unsigned) atomic_read(&cache->stats.read_miss),
		       (unsigned) atomic_read(&cache->stats.write_hit),
		       (unsigned) atomic_read(&cache->stats.write_miss),
		       (unsigned) atomic_read(&cache->stats.demotion),
		       (unsigned) atomic_read(&cache->stats.promotion),
		       (unsigned long) atomic_read(&cache->nr_dirty));

		if (cache->features.metadata_version == 2)
			DMEMIT("2 metadata2 ");
		else
			DMEMIT("1 ");

		if (writethrough_mode(&cache->features))
			DMEMIT("writethrough ");

		else if (passthrough_mode(&cache->features))
			DMEMIT("passthrough ");

		else if (writeback_mode(&cache->features))
			DMEMIT("writeback ");

		else {
			DMERR("%s: internal error: unknown io mode: %d",
			      cache_device_name(cache), (int) cache->features.io_mode);
			goto err;
		}

		DMEMIT("2 migration_threshold %llu ", (unsigned long long) cache->migration_threshold);

		DMEMIT("%s ", dm_cache_policy_get_name(cache->policy));
		if (sz < maxlen) {
			r = policy_emit_config_values(cache->policy, result, maxlen, &sz);
			if (r)
				DMERR("%s: policy_emit_config_values returned %d",
				      cache_device_name(cache), r);
		}

		if (get_cache_mode(cache) == CM_READ_ONLY)
			DMEMIT("ro ");
		else
			DMEMIT("rw ");

		r = dm_cache_metadata_needs_check(cache->cmd, &needs_check);

		if (r || needs_check)
			DMEMIT("needs_check ");
		else
			DMEMIT("- ");

		break;

	case STATUSTYPE_TABLE:
		format_dev_t(buf, cache->metadata_dev->bdev->bd_dev);
		DMEMIT("%s ", buf);
		format_dev_t(buf, cache->cache_dev->bdev->bd_dev);
		DMEMIT("%s ", buf);
		format_dev_t(buf, cache->origin_dev->bdev->bd_dev);
		DMEMIT("%s", buf);

		for (i = 0; i < cache->nr_ctr_args - 1; i++)
			DMEMIT(" %s", cache->ctr_args[i]);
		if (cache->nr_ctr_args)
			DMEMIT(" %s", cache->ctr_args[cache->nr_ctr_args - 1]);
	}

	return;

err:
	DMEMIT("Error");
}

Contributors
Person Tokens Prop Commits CommitProp
Joe Thornber 583 86.37% 6 50.00%
Mike Snitzer 90 13.33% 5 41.67%
Anssi Hannula 2 0.30% 1 8.33%
Total 675 100.00% 12 100.00%

/*
 * Defines a range of cblocks, begin to (end - 1) are in the range.  end is
 * the one-past-the-end value.
 */

struct cblock_range {
	
dm_cblock_t begin;
	
dm_cblock_t end;
};

/*
 * A cache block range can take two forms:
 *
 * i) A single cblock, eg. '3456'
 * ii) A begin and end cblock with a dash between, eg. 123-234
 */


static int parse_cblock_range(struct cache *cache, const char *str,
			      struct cblock_range *result)
{
	char dummy;
	uint64_t b, e;
	int r;

	/*
         * Try and parse form (ii) first.
         */
	r = sscanf(str, "%llu-%llu%c", &b, &e, &dummy);
	if (r < 0)
		return r;

	if (r == 2) {
		result->begin = to_cblock(b);
		result->end = to_cblock(e);
		return 0;
	}

	/*
         * That didn't work, try form (i).
         */
	r = sscanf(str, "%llu%c", &b, &dummy);
	if (r < 0)
		return r;

	if (r == 1) {
		result->begin = to_cblock(b);
		result->end = to_cblock(from_cblock(result->begin) + 1u);
		return 0;
	}

	DMERR("%s: invalid cblock range '%s'", cache_device_name(cache), str);
	return -EINVAL;
}

Contributors
Person Tokens Prop Commits CommitProp
Joe Thornber 160 96.39% 2 66.67%
Mike Snitzer 6 3.61% 1 33.33%
Total 166 100.00% 3 100.00%



static int validate_cblock_range(struct cache *cache, struct cblock_range *range)
{
	uint64_t b = from_cblock(range->begin);
	uint64_t e = from_cblock(range->end);
	uint64_t n = from_cblock(cache->cache_size);

	if (b >= n) {
		DMERR("%s: begin cblock out of range: %llu >= %llu",
		      cache_device_name(cache), b, n);
		return -EINVAL;
	}

	if (e > n) {
		DMERR("%s: end cblock out of range: %llu > %llu",
		      cache_device_name(cache), e, n);
		return -EINVAL;
	}

	if (b >= e) {
		DMERR("%s: invalid cblock range: %llu >= %llu",
		      cache_device_name(cache), b, e);
		return -EINVAL;
	}

	return 0;
}

Contributors
Person Tokens Prop Commits CommitProp
Joe Thornber 109 85.83% 1 50.00%
Mike Snitzer 18 14.17% 1 50.00%
Total 127 100.00% 2 100.00%



static inline dm_cblock_t cblock_succ(dm_cblock_t b)
{
	return to_cblock(from_cblock(b) + 1);
}

Contributors
Person Tokens Prop Commits CommitProp
Joe Thornber 21 100.00% 1 100.00%
Total 21 100.00% 1 100.00%



static int request_invalidation(struct cache *cache, struct cblock_range *range)
{
	int r = 0;

	/*
         * We don't need to do any locking here because we know we're in
         * passthrough mode.  There's is potential for a race between an
         * invalidation triggered by an io and an invalidation message.  This
         * is harmless, we must not worry if the policy call fails.
         */
	while (range->begin != range->end) {
		r = invalidate_cblock(cache, range->begin);
		if (r)
			return r;

		range->begin = cblock_succ(range->begin);
	}

	cache->commit_requested = true;
	return r;
}

Contributors
Person Tokens Prop Commits CommitProp
Joe Thornber 72 100.00% 2 100.00%
Total 72 100.00% 2 100.00%



static int process_invalidate_cblocks_message(struct cache *cache, unsigned count,
					      const char **cblock_ranges)
{
	int r = 0;
	unsigned i;
	struct cblock_range range;

	if (!passthrough_mode(&cache->features)) {
		DMERR("%s: cache has to be in passthrough mode for invalidation",
		      cache_device_name(cache));
		return -EPERM;
	}

	for (i = 0; i < count; i++) {
		r = parse_cblock_range(cache, cblock_ranges[i], &range);
		if (r)
			break;

		r = validate_cblock_range(cache, &range);
		if (r)
			break;

		/*
                 * Pass begin and end origin blocks to the worker and wake it.
                 */
		r = request_invalidation(cache, &range);
		if (r)
			break;
	}

	return r;
}

Contributors
Person Tokens Prop Commits CommitProp
Joe Thornber 122 95.31% 1 50.00%
Mike Snitzer 6 4.69% 1 50.00%
Total 128 100.00% 2 100.00%

/*
 * Supports
 *      "<key> <value>"
 * and
 *     "invalidate_cblocks [(<begin>)|(<begin>-<end>)]*
 *
 * The key migration_threshold is supported by the cache target core.
 */


static int cache_message(struct dm_target *ti, unsigned argc, char **argv)
{
	struct cache *cache = ti->private;

	if (!argc)
		return -EINVAL;

	if (get_cache_mode(cache) >= CM_READ_ONLY) {
		DMERR("%s: unable to service cache target messages in READ_ONLY or FAIL mode",
		      cache_device_name(cache));
		return -EOPNOTSUPP;
	}

	if (!strcasecmp(argv[0], "invalidate_cblocks"))
		return process_invalidate_cblocks_message(cache, argc - 1, (const char **) argv + 1);

	if (argc != 2)
		return -EINVAL;

	return set_config_value(cache, argv[0], argv[1]);
}

Contributors
Person Tokens Prop Commits CommitProp
Joe Thornber 114 94.21% 4 66.67%
Mike Snitzer 7 5.79% 2 33.33%
Total 121 100.00% 6 100.00%



static int cache_iterate_devices(struct dm_target *ti,
				 iterate_devices_callout_fn fn, void *data)
{
	int r = 0;
	struct cache *cache = ti->private;

	r = fn(ti, cache->cache_dev, 0, get_dev_size(cache->cache_dev), data);
	if (!r)
		r = fn(ti, cache->origin_dev, 0, ti->len, data);

	return r;
}

Contributors
Person Tokens Prop Commits CommitProp
Joe Thornber 81 100.00% 1 100.00%
Total 81 100.00% 1 100.00%



static void set_discard_limits(struct cache *cache, struct queue_limits *limits)
{
	/*
         * FIXME: these limits may be incompatible with the cache device
         */
	limits->max_discard_sectors = min_t(sector_t, cache->discard_block_size * 1024,
					    cache->origin_sectors);
	limits->discard_granularity = cache->discard_block_size << SECTOR_SHIFT;
}

Contributors
Person Tokens Prop Commits CommitProp
Joe Thornber 46 100.00% 4 100.00%
Total 46 100.00% 4 100.00%



static void cache_io_hints(struct dm_target *ti, struct queue_limits *limits)
{
	struct cache *cache = ti->private;
	uint64_t io_opt_sectors = limits->io_opt >> SECTOR_SHIFT;

	/*
         * If the system-determined stacked limits are compatible with the
         * cache's blocksize (io_opt is a factor) do not override them.
         */
	if (io_opt_sectors < cache->sectors_per_block ||
	    do_div(io_opt_sectors, cache->sectors_per_block)) {
		blk_limits_io_min(limits, cache->sectors_per_block << SECTOR_SHIFT);
		blk_limits_io_opt(limits, cache->sectors_per_block << SECTOR_SHIFT);
	}
	set_discard_limits(cache, limits);
}

Contributors
Person Tokens Prop Commits CommitProp
Joe Thornber 49 59.04% 1 33.33%
Mike Snitzer 34 40.96% 2 66.67%
Total 83 100.00% 3 100.00%

/*----------------------------------------------------------------*/


static struct target_type cache_target = {
	.name = "cache",
	.version = {2, 0, 0},
	.module = THIS_MODULE,
	.ctr = cache_ctr,
	.dtr = cache_dtr,
	.map = cache_map,
	.end_io = cache_end_io,
	.postsuspend = cache_postsuspend,
	.preresume = cache_preresume,
	.resume = cache_resume,
	.status = cache_status,
	.message = cache_message,
	.iterate_devices = cache_iterate_devices,
	.io_hints = cache_io_hints,
};



static int __init dm_cache_init(void)
{
	int r;

	r = dm_register_target(&cache_target);
	if (r) {
		DMERR("cache target registration failed: %d", r);
		return r;
	}

	migration_cache = KMEM_CACHE(dm_cache_migration, 0);
	if (!migration_cache) {
		dm_unregister_target(&cache_target);
		return -ENOMEM;
	}

	return 0;
}

Contributors
Person Tokens Prop Commits CommitProp
Joe Thornber 65 100.00% 1 100.00%
Total 65 100.00% 1 100.00%



static void __exit dm_cache_exit(void)
{
	dm_unregister_target(&cache_target);
	kmem_cache_destroy(migration_cache);
}

Contributors
Person Tokens Prop Commits CommitProp
Joe Thornber 20 100.00% 1 100.00%
Total 20 100.00% 1 100.00%


module_init(dm_cache_init);

module_exit(dm_cache_exit);

MODULE_DESCRIPTION(DM_NAME " cache target");
MODULE_AUTHOR("Joe Thornber <ejt@redhat.com>");
MODULE_LICENSE("GPL");
Overall Contributors
Person Tokens Prop Commits CommitProp
Joe Thornber 14603 96.46% 43 52.44%
Mike Snitzer 338 2.23% 18 21.95%
Alasdair G. Kergon 61 0.40% 1 1.22%
Christoph Hellwig 57 0.38% 5 6.10%
Heinz Mauelshagen 25 0.17% 5 6.10%
Mikulas Patocka 22 0.15% 2 2.44%
Anssi Hannula 14 0.09% 2 2.44%
Darrick J. Wong 6 0.04% 1 1.22%
Wei Yongjun 5 0.03% 1 1.22%
Manuel Schölling 3 0.02% 1 1.22%
Michael Christie 2 0.01% 1 1.22%
Eric Biggers 2 0.01% 1 1.22%
Vincent Pelletier 1 0.01% 1 1.22%
Total 15139 100.00% 82 100.00%
Directory: drivers/md

Information contained on this website is for historical information purposes only and does not indicate or represent copyright ownership.
Created with cregit.
Person	Tokens	Prop	Commits	CommitProp
Joe Thornber	37	100.00%	1	100.00%
Total	37	100.00%	1	100.00%
cregit-Linux how code gets into the kernel

Release 4.14 drivers/md/dm-cache-target.c

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