[linux-block.git] / drivers / md / dm-cache-metadata.h

/* SPDX-License-Identifier: GPL-2.0-only */
/*
 * 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

struct dm_cache_metadata;

/*
 * 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 int 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 int 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
 * necessarily 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
3bd94003	1	/* SPDX-License-Identifier: GPL-2.0-only */
c6b4fcba JT	2	/*
	3	* Copyright (C) 2012 Red Hat, Inc.
	4	*
	5	* This file is released under the GPL.
	6	*/
	7
	8	#ifndef DM_CACHE_METADATA_H
	9	#define DM_CACHE_METADATA_H
	10
	11	#include "dm-cache-block-types.h"
	12	#include "dm-cache-policy-internal.h"
895b47d7	13	#include "persistent-data/dm-space-map-metadata.h"
c6b4fcba JT	14
	15	/----------------------------------------------------------------/
	16
895b47d7	17	#define DM_CACHE_METADATA_BLOCK_SIZE DM_SM_METADATA_BLOCK_SIZE
c6b4fcba JT	18
	19	/* FIXME: remove this restriction */
	20	/*
	21	* The metadata device is currently limited in size.
c6b4fcba	22	*/
895b47d7	23	#define DM_CACHE_METADATA_MAX_SECTORS DM_SM_METADATA_MAX_SECTORS
c6b4fcba JT	24
	25	/*
	26	* A metadata device larger than 16GB triggers a warning.
	27	*/
	28	#define DM_CACHE_METADATA_MAX_SECTORS_WARNING (16 * (1024 * 1024 * 1024 >> SECTOR_SHIFT))
	29
	30	/----------------------------------------------------------------/
	31
	32	/*
	33	* Ext[234]-style compat feature flags.
	34	*
	35	* A new feature which old metadata will still be compatible with should
	36	* define a DM_CACHE_FEATURE_COMPAT_* flag (rarely useful).
	37	*
	38	* A new feature that is not compatible with old code should define a
	39	* DM_CACHE_FEATURE_INCOMPAT_* flag and guard the relevant code with
	40	* that flag.
	41	*
	42	* A new feature that is not compatible with old code accessing the
	43	* metadata RDWR should define a DM_CACHE_FEATURE_RO_COMPAT_* flag and
	44	* guard the relevant code with that flag.
	45	*
	46	* As these various flags are defined they should be added to the
	47	* following masks.
	48	*/
629d0a8a	49
c6b4fcba JT	50	#define DM_CACHE_FEATURE_COMPAT_SUPP 0UL
	51	#define DM_CACHE_FEATURE_COMPAT_RO_SUPP 0UL
	52	#define DM_CACHE_FEATURE_INCOMPAT_SUPP 0UL
	53
b29d4986 JT	54	struct dm_cache_metadata;
b29d4986 JT	55
c6b4fcba	56	/*
629d0a8a JT	57	* Reopens or creates a new, empty metadata volume. Returns an ERR_PTR on
629d0a8a JT	58	* failure. If reopening then features must match.
c6b4fcba JT	59	*/
	60	struct dm_cache_metadata dm_cache_metadata_open(struct block_device bdev,
	61	sector_t data_block_size,
	62	bool may_format_device,
629d0a8a	63	size_t policy_hint_size,
86a3238c	64	unsigned int metadata_version);
c6b4fcba JT	65
	66	void dm_cache_metadata_close(struct dm_cache_metadata *cmd);
	67
	68	/*
	69	* The metadata needs to know how many cache blocks there are. We don't
	70	* care about the origin, assuming the core target is giving us valid
	71	* origin blocks to map to.
	72	*/
	73	int dm_cache_resize(struct dm_cache_metadata *cmd, dm_cblock_t new_cache_size);
d14fcf3d	74	int dm_cache_size(struct dm_cache_metadata cmd, dm_cblock_t result);
c6b4fcba JT	75
	76	int dm_cache_discard_bitset_resize(struct dm_cache_metadata *cmd,
	77	sector_t discard_block_size,
1bad9bc4	78	dm_dblock_t new_nr_entries);
c6b4fcba JT	79
c6b4fcba JT	80	typedef int (load_discard_fn)(void context, sector_t discard_block_size,
1bad9bc4	81	dm_dblock_t dblock, bool discarded);
c6b4fcba JT	82	int dm_cache_load_discards(struct dm_cache_metadata *cmd,
	83	load_discard_fn fn, void *context);
	84
1bad9bc4	85	int dm_cache_set_discard(struct dm_cache_metadata *cmd, dm_dblock_t dblock, bool discard);
c6b4fcba JT	86
	87	int dm_cache_remove_mapping(struct dm_cache_metadata *cmd, dm_cblock_t cblock);
	88	int dm_cache_insert_mapping(struct dm_cache_metadata *cmd, dm_cblock_t cblock, dm_oblock_t oblock);
	89	int dm_cache_changed_this_transaction(struct dm_cache_metadata *cmd);
	90
	91	typedef int (load_mapping_fn)(void context, dm_oblock_t oblock,
	92	dm_cblock_t cblock, bool dirty,
	93	uint32_t hint, bool hint_valid);
	94	int dm_cache_load_mappings(struct dm_cache_metadata *cmd,
ea2dd8c1	95	struct dm_cache_policy *policy,
c6b4fcba JT	96	load_mapping_fn fn,
	97	void *context);
	98
629d0a8a	99	int dm_cache_set_dirty_bits(struct dm_cache_metadata *cmd,
86a3238c	100	unsigned int nr_bits, unsigned long *bits);
c6b4fcba JT	101
	102	struct dm_cache_statistics {
	103	uint32_t read_hits;
	104	uint32_t read_misses;
	105	uint32_t write_hits;
	106	uint32_t write_misses;
	107	};
	108
	109	void dm_cache_metadata_get_stats(struct dm_cache_metadata *cmd,
	110	struct dm_cache_statistics *stats);
028ae9f7 JT	111
	112	/*
	113	* 'void' because it's no big deal if it fails.
	114	*/
c6b4fcba JT	115	void dm_cache_metadata_set_stats(struct dm_cache_metadata *cmd,
	116	struct dm_cache_statistics *stats);
	117
	118	int dm_cache_commit(struct dm_cache_metadata *cmd, bool clean_shutdown);
	119
	120	int dm_cache_get_free_metadata_block_count(struct dm_cache_metadata *cmd,
	121	dm_block_t *result);
	122
	123	int dm_cache_get_metadata_dev_size(struct dm_cache_metadata *cmd,
	124	dm_block_t *result);
	125
	126	void dm_cache_dump(struct dm_cache_metadata *cmd);
	127
	128	/*
	129	* The policy is invited to save a 32bit hint value for every cblock (eg,
	130	* for a hit count). These are stored against the policy name. If
	131	* policies are changed, then hints will be lost. If the machine crashes,
	132	* hints will be lost.
	133	*
	134	* The hints are indexed by the cblock, but many policies will not
5c29e784	135	* necessarily have a fast way of accessing efficiently via cblock. So
c6b4fcba JT	136	* rather than querying the policy for each cblock, we let it walk its data
	137	* structures and fill in the hints in whatever order it wishes.
	138	*/
0596661f	139	int dm_cache_write_hints(struct dm_cache_metadata cmd, struct dm_cache_policy p);
c6b4fcba	140
2ee57d58 JT	141	/*
	142	* Query method. Are all the blocks in the cache clean?
	143	*/
	144	int dm_cache_metadata_all_clean(struct dm_cache_metadata cmd, bool result);
	145
d14fcf3d	146	int dm_cache_metadata_needs_check(struct dm_cache_metadata cmd, bool result);
028ae9f7 JT	147	int dm_cache_metadata_set_needs_check(struct dm_cache_metadata *cmd);
	148	void dm_cache_metadata_set_read_only(struct dm_cache_metadata *cmd);
	149	void dm_cache_metadata_set_read_write(struct dm_cache_metadata *cmd);
	150	int dm_cache_metadata_abort(struct dm_cache_metadata *cmd);
	151
c6b4fcba JT	152	/----------------------------------------------------------------/
	153
	154	#endif /* DM_CACHE_METADATA_H */