[mirror_ubuntu-artful-kernel.git] / drivers / md / dm-cache-metadata.h

/*
 * Copyright (C) 2012 Red Hat, Inc.
 *
 * This file is released under the GPL.
 */

#ifndef DM_CACHE_METADATA_H
#define DM_CACHE_METADATA_H

#include "dm-cache-block-types.h"
#include "dm-cache-policy-internal.h"
#include "persistent-data/dm-space-map-metadata.h"

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

#define DM_CACHE_METADATA_BLOCK_SIZE DM_SM_METADATA_BLOCK_SIZE

/* FIXME: remove this restriction */
/*
 * The metadata device is currently limited in size.
 */
#define DM_CACHE_METADATA_MAX_SECTORS DM_SM_METADATA_MAX_SECTORS

/*
 * A metadata device larger than 16GB triggers a warning.
 */
#define DM_CACHE_METADATA_MAX_SECTORS_WARNING (16 * (1024 * 1024 * 1024 >> SECTOR_SHIFT))

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

/*
 * Ext[234]-style compat feature flags.
 *
 * A new feature which old metadata will still be compatible with should
 * define a DM_CACHE_FEATURE_COMPAT_* flag (rarely useful).
 *
 * A new feature that is not compatible with old code should define a
 * DM_CACHE_FEATURE_INCOMPAT_* flag and guard the relevant code with
 * that flag.
 *
 * A new feature that is not compatible with old code accessing the
 * metadata RDWR should define a DM_CACHE_FEATURE_RO_COMPAT_* flag and
 * guard the relevant code with that flag.
 *
 * As these various flags are defined they should be added to the
 * following masks.
 */

#define DM_CACHE_FEATURE_COMPAT_SUPP	  0UL
#define DM_CACHE_FEATURE_COMPAT_RO_SUPP	  0UL
#define DM_CACHE_FEATURE_INCOMPAT_SUPP	  0UL

/*
 * Reopens or creates a new, empty metadata volume.  Returns an ERR_PTR on
 * failure.  If reopening then features must match.
 */
struct dm_cache_metadata *dm_cache_metadata_open(struct block_device *bdev,
						 sector_t data_block_size,
						 bool may_format_device,
						 size_t policy_hint_size,
						 unsigned metadata_version);

void dm_cache_metadata_close(struct dm_cache_metadata *cmd);

/*
 * The metadata needs to know how many cache blocks there are.  We don't
 * care about the origin, assuming the core target is giving us valid
 * origin blocks to map to.
 */
int dm_cache_resize(struct dm_cache_metadata *cmd, dm_cblock_t new_cache_size);
int dm_cache_size(struct dm_cache_metadata *cmd, dm_cblock_t *result);

int dm_cache_discard_bitset_resize(struct dm_cache_metadata *cmd,
				   sector_t discard_block_size,
				   dm_dblock_t new_nr_entries);

typedef int (*load_discard_fn)(void *context, sector_t discard_block_size,
			       dm_dblock_t dblock, bool discarded);
int dm_cache_load_discards(struct dm_cache_metadata *cmd,
			   load_discard_fn fn, void *context);

int dm_cache_set_discard(struct dm_cache_metadata *cmd, dm_dblock_t dblock, bool discard);

int dm_cache_remove_mapping(struct dm_cache_metadata *cmd, dm_cblock_t cblock);
int dm_cache_insert_mapping(struct dm_cache_metadata *cmd, dm_cblock_t cblock, dm_oblock_t oblock);
int dm_cache_changed_this_transaction(struct dm_cache_metadata *cmd);

typedef int (*load_mapping_fn)(void *context, dm_oblock_t oblock,
			       dm_cblock_t cblock, bool dirty,
			       uint32_t hint, bool hint_valid);
int dm_cache_load_mappings(struct dm_cache_metadata *cmd,
			   struct dm_cache_policy *policy,
			   load_mapping_fn fn,
			   void *context);

int dm_cache_set_dirty_bits(struct dm_cache_metadata *cmd,
			    unsigned nr_bits, unsigned long *bits);

struct dm_cache_statistics {
	uint32_t read_hits;
	uint32_t read_misses;
	uint32_t write_hits;
	uint32_t write_misses;
};

void dm_cache_metadata_get_stats(struct dm_cache_metadata *cmd,
				 struct dm_cache_statistics *stats);

/*
 * 'void' because it's no big deal if it fails.
 */
void dm_cache_metadata_set_stats(struct dm_cache_metadata *cmd,
				 struct dm_cache_statistics *stats);

int dm_cache_commit(struct dm_cache_metadata *cmd, bool clean_shutdown);

int dm_cache_get_free_metadata_block_count(struct dm_cache_metadata *cmd,
					   dm_block_t *result);

int dm_cache_get_metadata_dev_size(struct dm_cache_metadata *cmd,
				   dm_block_t *result);

void dm_cache_dump(struct dm_cache_metadata *cmd);

/*
 * The policy is invited to save a 32bit hint value for every cblock (eg,
 * for a hit count).  These are stored against the policy name.  If
 * policies are changed, then hints will be lost.  If the machine crashes,
 * hints will be lost.
 *
 * The hints are indexed by the cblock, but many policies will not
 * neccessarily have a fast way of accessing efficiently via cblock.  So
 * rather than querying the policy for each cblock, we let it walk its data
 * structures and fill in the hints in whatever order it wishes.
 */
int dm_cache_write_hints(struct dm_cache_metadata *cmd, struct dm_cache_policy *p);

/*
 * Query method.  Are all the blocks in the cache clean?
 */
int dm_cache_metadata_all_clean(struct dm_cache_metadata *cmd, bool *result);

int dm_cache_metadata_needs_check(struct dm_cache_metadata *cmd, bool *result);
int dm_cache_metadata_set_needs_check(struct dm_cache_metadata *cmd);
void dm_cache_metadata_set_read_only(struct dm_cache_metadata *cmd);
void dm_cache_metadata_set_read_write(struct dm_cache_metadata *cmd);
int dm_cache_metadata_abort(struct dm_cache_metadata *cmd);

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

#endif /* DM_CACHE_METADATA_H */
Commit	Line	Data
c6b4fcba JT	1	/*
	2	* Copyright (C) 2012 Red Hat, Inc.
	3	*
	4	* This file is released under the GPL.
	5	*/
	6
	7	#ifndef DM_CACHE_METADATA_H
	8	#define DM_CACHE_METADATA_H
	9
	10	#include "dm-cache-block-types.h"
	11	#include "dm-cache-policy-internal.h"
895b47d7	12	#include "persistent-data/dm-space-map-metadata.h"
c6b4fcba JT	13
	14	/----------------------------------------------------------------/
	15
895b47d7	16	#define DM_CACHE_METADATA_BLOCK_SIZE DM_SM_METADATA_BLOCK_SIZE
c6b4fcba JT	17
	18	/* FIXME: remove this restriction */
	19	/*
	20	* The metadata device is currently limited in size.
c6b4fcba	21	*/
895b47d7	22	#define DM_CACHE_METADATA_MAX_SECTORS DM_SM_METADATA_MAX_SECTORS
c6b4fcba JT	23
	24	/*
	25	* A metadata device larger than 16GB triggers a warning.
	26	*/
	27	#define DM_CACHE_METADATA_MAX_SECTORS_WARNING (16 * (1024 * 1024 * 1024 >> SECTOR_SHIFT))
	28
	29	/----------------------------------------------------------------/
	30
	31	/*
	32	* Ext[234]-style compat feature flags.
	33	*
	34	* A new feature which old metadata will still be compatible with should
	35	* define a DM_CACHE_FEATURE_COMPAT_* flag (rarely useful).
	36	*
	37	* A new feature that is not compatible with old code should define a
	38	* DM_CACHE_FEATURE_INCOMPAT_* flag and guard the relevant code with
	39	* that flag.
	40	*
	41	* A new feature that is not compatible with old code accessing the
	42	* metadata RDWR should define a DM_CACHE_FEATURE_RO_COMPAT_* flag and
	43	* guard the relevant code with that flag.
	44	*
	45	* As these various flags are defined they should be added to the
	46	* following masks.
	47	*/
629d0a8a	48
c6b4fcba JT	49	#define DM_CACHE_FEATURE_COMPAT_SUPP 0UL
	50	#define DM_CACHE_FEATURE_COMPAT_RO_SUPP 0UL
	51	#define DM_CACHE_FEATURE_INCOMPAT_SUPP 0UL
	52
	53	/*
629d0a8a JT	54	* Reopens or creates a new, empty metadata volume. Returns an ERR_PTR on
629d0a8a JT	55	* failure. If reopening then features must match.
c6b4fcba JT	56	*/
	57	struct dm_cache_metadata dm_cache_metadata_open(struct block_device bdev,
	58	sector_t data_block_size,
	59	bool may_format_device,
629d0a8a JT	60	size_t policy_hint_size,
629d0a8a JT	61	unsigned metadata_version);
c6b4fcba JT	62
	63	void dm_cache_metadata_close(struct dm_cache_metadata *cmd);
	64
	65	/*
	66	* The metadata needs to know how many cache blocks there are. We don't
	67	* care about the origin, assuming the core target is giving us valid
	68	* origin blocks to map to.
	69	*/
	70	int dm_cache_resize(struct dm_cache_metadata *cmd, dm_cblock_t new_cache_size);
d14fcf3d	71	int dm_cache_size(struct dm_cache_metadata cmd, dm_cblock_t result);
c6b4fcba JT	72
	73	int dm_cache_discard_bitset_resize(struct dm_cache_metadata *cmd,
	74	sector_t discard_block_size,
1bad9bc4	75	dm_dblock_t new_nr_entries);
c6b4fcba JT	76
c6b4fcba JT	77	typedef int (load_discard_fn)(void context, sector_t discard_block_size,
1bad9bc4	78	dm_dblock_t dblock, bool discarded);
c6b4fcba JT	79	int dm_cache_load_discards(struct dm_cache_metadata *cmd,
	80	load_discard_fn fn, void *context);
	81
1bad9bc4	82	int dm_cache_set_discard(struct dm_cache_metadata *cmd, dm_dblock_t dblock, bool discard);
c6b4fcba JT	83
	84	int dm_cache_remove_mapping(struct dm_cache_metadata *cmd, dm_cblock_t cblock);
	85	int dm_cache_insert_mapping(struct dm_cache_metadata *cmd, dm_cblock_t cblock, dm_oblock_t oblock);
	86	int dm_cache_changed_this_transaction(struct dm_cache_metadata *cmd);
	87
	88	typedef int (load_mapping_fn)(void context, dm_oblock_t oblock,
	89	dm_cblock_t cblock, bool dirty,
	90	uint32_t hint, bool hint_valid);
	91	int dm_cache_load_mappings(struct dm_cache_metadata *cmd,
ea2dd8c1	92	struct dm_cache_policy *policy,
c6b4fcba JT	93	load_mapping_fn fn,
	94	void *context);
	95
629d0a8a JT	96	int dm_cache_set_dirty_bits(struct dm_cache_metadata *cmd,
629d0a8a JT	97	unsigned nr_bits, unsigned long *bits);
c6b4fcba JT	98
	99	struct dm_cache_statistics {
	100	uint32_t read_hits;
	101	uint32_t read_misses;
	102	uint32_t write_hits;
	103	uint32_t write_misses;
	104	};
	105
	106	void dm_cache_metadata_get_stats(struct dm_cache_metadata *cmd,
	107	struct dm_cache_statistics *stats);
028ae9f7 JT	108
	109	/*
	110	* 'void' because it's no big deal if it fails.
	111	*/
c6b4fcba JT	112	void dm_cache_metadata_set_stats(struct dm_cache_metadata *cmd,
	113	struct dm_cache_statistics *stats);
	114
	115	int dm_cache_commit(struct dm_cache_metadata *cmd, bool clean_shutdown);
	116
	117	int dm_cache_get_free_metadata_block_count(struct dm_cache_metadata *cmd,
	118	dm_block_t *result);
	119
	120	int dm_cache_get_metadata_dev_size(struct dm_cache_metadata *cmd,
	121	dm_block_t *result);
	122
	123	void dm_cache_dump(struct dm_cache_metadata *cmd);
	124
	125	/*
	126	* The policy is invited to save a 32bit hint value for every cblock (eg,
	127	* for a hit count). These are stored against the policy name. If
	128	* policies are changed, then hints will be lost. If the machine crashes,
	129	* hints will be lost.
	130	*
	131	* The hints are indexed by the cblock, but many policies will not
	132	* neccessarily have a fast way of accessing efficiently via cblock. So
	133	* rather than querying the policy for each cblock, we let it walk its data
	134	* structures and fill in the hints in whatever order it wishes.
	135	*/
0596661f	136	int dm_cache_write_hints(struct dm_cache_metadata cmd, struct dm_cache_policy p);
c6b4fcba	137
2ee57d58 JT	138	/*
	139	* Query method. Are all the blocks in the cache clean?
	140	*/
	141	int dm_cache_metadata_all_clean(struct dm_cache_metadata cmd, bool result);
	142
d14fcf3d	143	int dm_cache_metadata_needs_check(struct dm_cache_metadata cmd, bool result);
028ae9f7 JT	144	int dm_cache_metadata_set_needs_check(struct dm_cache_metadata *cmd);
	145	void dm_cache_metadata_set_read_only(struct dm_cache_metadata *cmd);
	146	void dm_cache_metadata_set_read_write(struct dm_cache_metadata *cmd);
	147	int dm_cache_metadata_abort(struct dm_cache_metadata *cmd);
	148
c6b4fcba JT	149	/----------------------------------------------------------------/
	150
	151	#endif /* DM_CACHE_METADATA_H */