[mirror_ubuntu-zesty-kernel.git] / drivers / md / dm-thin-metadata.h

/*
 * Copyright (C) 2010-2011 Red Hat, Inc.
 *
 * This file is released under the GPL.
 */

#ifndef DM_THIN_METADATA_H
#define DM_THIN_METADATA_H

#include "persistent-data/dm-block-manager.h"
#include "persistent-data/dm-space-map.h"
#include "persistent-data/dm-space-map-metadata.h"

#define THIN_METADATA_BLOCK_SIZE DM_SM_METADATA_BLOCK_SIZE

/*
 * The metadata device is currently limited in size.
 */
#define THIN_METADATA_MAX_SECTORS DM_SM_METADATA_MAX_SECTORS

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

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

/*
 * Thin metadata superblock flags.
 */
#define THIN_METADATA_NEEDS_CHECK_FLAG (1 << 0)

struct dm_pool_metadata;
struct dm_thin_device;

/*
 * Device identifier
 */
typedef uint64_t dm_thin_id;

/*
 * Reopens or creates a new, empty metadata volume.
 */
struct dm_pool_metadata *dm_pool_metadata_open(struct block_device *bdev,
					       sector_t data_block_size,
					       bool format_device);

int dm_pool_metadata_close(struct dm_pool_metadata *pmd);

/*
 * Compat feature flags.  Any incompat flags beyond the ones
 * specified below will prevent use of the thin metadata.
 */
#define THIN_FEATURE_COMPAT_SUPP	  0UL
#define THIN_FEATURE_COMPAT_RO_SUPP	  0UL
#define THIN_FEATURE_INCOMPAT_SUPP	  0UL

/*
 * Device creation/deletion.
 */
int dm_pool_create_thin(struct dm_pool_metadata *pmd, dm_thin_id dev);

/*
 * An internal snapshot.
 *
 * You can only snapshot a quiesced origin i.e. one that is either
 * suspended or not instanced at all.
 */
int dm_pool_create_snap(struct dm_pool_metadata *pmd, dm_thin_id dev,
			dm_thin_id origin);

/*
 * Deletes a virtual device from the metadata.  It _is_ safe to call this
 * when that device is open.  Operations on that device will just start
 * failing.  You still need to call close() on the device.
 */
int dm_pool_delete_thin_device(struct dm_pool_metadata *pmd,
			       dm_thin_id dev);

/*
 * Commits _all_ metadata changes: device creation, deletion, mapping
 * updates.
 */
int dm_pool_commit_metadata(struct dm_pool_metadata *pmd);

/*
 * Discards all uncommitted changes.  Rereads the superblock, rolling back
 * to the last good transaction.  Thin devices remain open.
 * dm_thin_aborted_changes() tells you if they had uncommitted changes.
 *
 * If this call fails it's only useful to call dm_pool_metadata_close().
 * All other methods will fail with -EINVAL.
 */
int dm_pool_abort_metadata(struct dm_pool_metadata *pmd);

/*
 * Set/get userspace transaction id.
 */
int dm_pool_set_metadata_transaction_id(struct dm_pool_metadata *pmd,
					uint64_t current_id,
					uint64_t new_id);

int dm_pool_get_metadata_transaction_id(struct dm_pool_metadata *pmd,
					uint64_t *result);

/*
 * Hold/get root for userspace transaction.
 *
 * The metadata snapshot is a copy of the current superblock (minus the
 * space maps).  Userland can access the data structures for READ
 * operations only.  A small performance hit is incurred by providing this
 * copy of the metadata to userland due to extra copy-on-write operations
 * on the metadata nodes.  Release this as soon as you finish with it.
 */
int dm_pool_reserve_metadata_snap(struct dm_pool_metadata *pmd);
int dm_pool_release_metadata_snap(struct dm_pool_metadata *pmd);

int dm_pool_get_metadata_snap(struct dm_pool_metadata *pmd,
			      dm_block_t *result);

/*
 * Actions on a single virtual device.
 */

/*
 * Opening the same device more than once will fail with -EBUSY.
 */
int dm_pool_open_thin_device(struct dm_pool_metadata *pmd, dm_thin_id dev,
			     struct dm_thin_device **td);

int dm_pool_close_thin_device(struct dm_thin_device *td);

dm_thin_id dm_thin_dev_id(struct dm_thin_device *td);

struct dm_thin_lookup_result {
	dm_block_t block;
	bool shared:1;
};

/*
 * Returns:
 *   -EWOULDBLOCK iff @can_issue_io is set and would issue IO
 *   -ENODATA iff that mapping is not present.
 *   0 success
 */
int dm_thin_find_block(struct dm_thin_device *td, dm_block_t block,
		       int can_issue_io, struct dm_thin_lookup_result *result);

/*
 * Retrieve the next run of contiguously mapped blocks.  Useful for working
 * out where to break up IO.  Returns 0 on success, < 0 on error.
 */
int dm_thin_find_mapped_range(struct dm_thin_device *td,
			      dm_block_t begin, dm_block_t end,
			      dm_block_t *thin_begin, dm_block_t *thin_end,
			      dm_block_t *pool_begin, bool *maybe_shared);

/*
 * Obtain an unused block.
 */
int dm_pool_alloc_data_block(struct dm_pool_metadata *pmd, dm_block_t *result);

/*
 * Insert or remove block.
 */
int dm_thin_insert_block(struct dm_thin_device *td, dm_block_t block,
			 dm_block_t data_block);

int dm_thin_remove_block(struct dm_thin_device *td, dm_block_t block);
int dm_thin_remove_range(struct dm_thin_device *td,
			 dm_block_t begin, dm_block_t end);

/*
 * Queries.
 */
bool dm_thin_changed_this_transaction(struct dm_thin_device *td);

bool dm_pool_changed_this_transaction(struct dm_pool_metadata *pmd);

bool dm_thin_aborted_changes(struct dm_thin_device *td);

int dm_thin_get_highest_mapped_block(struct dm_thin_device *td,
				     dm_block_t *highest_mapped);

int dm_thin_get_mapped_count(struct dm_thin_device *td, dm_block_t *result);

int dm_pool_get_free_block_count(struct dm_pool_metadata *pmd,
				 dm_block_t *result);

int dm_pool_get_free_metadata_block_count(struct dm_pool_metadata *pmd,
					  dm_block_t *result);

int dm_pool_get_metadata_dev_size(struct dm_pool_metadata *pmd,
				  dm_block_t *result);

int dm_pool_get_data_dev_size(struct dm_pool_metadata *pmd, dm_block_t *result);

int dm_pool_block_is_used(struct dm_pool_metadata *pmd, dm_block_t b, bool *result);

int dm_pool_inc_data_range(struct dm_pool_metadata *pmd, dm_block_t b, dm_block_t e);
int dm_pool_dec_data_range(struct dm_pool_metadata *pmd, dm_block_t b, dm_block_t e);

/*
 * Returns -ENOSPC if the new size is too small and already allocated
 * blocks would be lost.
 */
int dm_pool_resize_data_dev(struct dm_pool_metadata *pmd, dm_block_t new_size);
int dm_pool_resize_metadata_dev(struct dm_pool_metadata *pmd, dm_block_t new_size);

/*
 * Flicks the underlying block manager into read only mode, so you know
 * that nothing is changing.
 */
void dm_pool_metadata_read_only(struct dm_pool_metadata *pmd);
void dm_pool_metadata_read_write(struct dm_pool_metadata *pmd);

int dm_pool_register_metadata_threshold(struct dm_pool_metadata *pmd,
					dm_block_t threshold,
					dm_sm_threshold_fn fn,
					void *context);

/*
 * Updates the superblock immediately.
 */
int dm_pool_metadata_set_needs_check(struct dm_pool_metadata *pmd);
bool dm_pool_metadata_needs_check(struct dm_pool_metadata *pmd);

/*
 * Issue any prefetches that may be useful.
 */
void dm_pool_issue_prefetches(struct dm_pool_metadata *pmd);

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

#endif
Commit	Line	Data
991d9fa0 JT	1	/*
	2	* Copyright (C) 2010-2011 Red Hat, Inc.
	3	*
	4	* This file is released under the GPL.
	5	*/
	6
	7	#ifndef DM_THIN_METADATA_H
	8	#define DM_THIN_METADATA_H
	9
	10	#include "persistent-data/dm-block-manager.h"
ac8c3f3d	11	#include "persistent-data/dm-space-map.h"
7d48935e	12	#include "persistent-data/dm-space-map-metadata.h"
991d9fa0	13
7d48935e	14	#define THIN_METADATA_BLOCK_SIZE DM_SM_METADATA_BLOCK_SIZE
991d9fa0	15
c4a69ecd MS	16	/*
c4a69ecd MS	17	* The metadata device is currently limited in size.
c4a69ecd	18	*/
7d48935e	19	#define THIN_METADATA_MAX_SECTORS DM_SM_METADATA_MAX_SECTORS
c4a69ecd MS	20
	21	/*
	22	* A metadata device larger than 16GB triggers a warning.
	23	*/
	24	#define THIN_METADATA_MAX_SECTORS_WARNING (16 * (1024 * 1024 * 1024 >> SECTOR_SHIFT))
	25
991d9fa0 JT	26	/----------------------------------------------------------------/
991d9fa0 JT	27
07f2b6e0 MS	28	/*
	29	* Thin metadata superblock flags.
	30	*/
	31	#define THIN_METADATA_NEEDS_CHECK_FLAG (1 << 0)
	32
991d9fa0 JT	33	struct dm_pool_metadata;
	34	struct dm_thin_device;
	35
	36	/*
	37	* Device identifier
	38	*/
	39	typedef uint64_t dm_thin_id;
	40
	41	/*
	42	* Reopens or creates a new, empty metadata volume.
	43	*/
	44	struct dm_pool_metadata dm_pool_metadata_open(struct block_device bdev,
66b1edc0 JT	45	sector_t data_block_size,
66b1edc0 JT	46	bool format_device);
991d9fa0 JT	47
	48	int dm_pool_metadata_close(struct dm_pool_metadata *pmd);
	49
	50	/*
	51	* Compat feature flags. Any incompat flags beyond the ones
	52	* specified below will prevent use of the thin metadata.
	53	*/
	54	#define THIN_FEATURE_COMPAT_SUPP 0UL
	55	#define THIN_FEATURE_COMPAT_RO_SUPP 0UL
	56	#define THIN_FEATURE_INCOMPAT_SUPP 0UL
	57
	58	/*
	59	* Device creation/deletion.
	60	*/
	61	int dm_pool_create_thin(struct dm_pool_metadata *pmd, dm_thin_id dev);
	62
	63	/*
	64	* An internal snapshot.
	65	*
	66	* You can only snapshot a quiesced origin i.e. one that is either
	67	* suspended or not instanced at all.
	68	*/
	69	int dm_pool_create_snap(struct dm_pool_metadata *pmd, dm_thin_id dev,
	70	dm_thin_id origin);
	71
	72	/*
	73	* Deletes a virtual device from the metadata. It _is_ safe to call this
	74	* when that device is open. Operations on that device will just start
	75	* failing. You still need to call close() on the device.
	76	*/
	77	int dm_pool_delete_thin_device(struct dm_pool_metadata *pmd,
	78	dm_thin_id dev);
	79
	80	/*
	81	* Commits _all_ metadata changes: device creation, deletion, mapping
	82	* updates.
	83	*/
	84	int dm_pool_commit_metadata(struct dm_pool_metadata *pmd);
	85
da105ed5 JT	86	/*
	87	* Discards all uncommitted changes. Rereads the superblock, rolling back
	88	* to the last good transaction. Thin devices remain open.
	89	* dm_thin_aborted_changes() tells you if they had uncommitted changes.
	90	*
	91	* If this call fails it's only useful to call dm_pool_metadata_close().
	92	* All other methods will fail with -EINVAL.
	93	*/
	94	int dm_pool_abort_metadata(struct dm_pool_metadata *pmd);
	95
991d9fa0 JT	96	/*
	97	* Set/get userspace transaction id.
	98	*/
	99	int dm_pool_set_metadata_transaction_id(struct dm_pool_metadata *pmd,
	100	uint64_t current_id,
	101	uint64_t new_id);
	102
	103	int dm_pool_get_metadata_transaction_id(struct dm_pool_metadata *pmd,
	104	uint64_t *result);
	105
	106	/*
	107	* Hold/get root for userspace transaction.
cc8394d8 JT	108	*
	109	* The metadata snapshot is a copy of the current superblock (minus the
	110	* space maps). Userland can access the data structures for READ
	111	* operations only. A small performance hit is incurred by providing this
	112	* copy of the metadata to userland due to extra copy-on-write operations
	113	* on the metadata nodes. Release this as soon as you finish with it.
991d9fa0	114	*/
cc8394d8 JT	115	int dm_pool_reserve_metadata_snap(struct dm_pool_metadata *pmd);
cc8394d8 JT	116	int dm_pool_release_metadata_snap(struct dm_pool_metadata *pmd);
991d9fa0	117
cc8394d8 JT	118	int dm_pool_get_metadata_snap(struct dm_pool_metadata *pmd,
cc8394d8 JT	119	dm_block_t *result);
991d9fa0 JT	120
	121	/*
	122	* Actions on a single virtual device.
	123	*/
	124
	125	/*
	126	* Opening the same device more than once will fail with -EBUSY.
	127	*/
	128	int dm_pool_open_thin_device(struct dm_pool_metadata *pmd, dm_thin_id dev,
	129	struct dm_thin_device **td);
	130
	131	int dm_pool_close_thin_device(struct dm_thin_device *td);
	132
	133	dm_thin_id dm_thin_dev_id(struct dm_thin_device *td);
	134
	135	struct dm_thin_lookup_result {
	136	dm_block_t block;
7f214665	137	bool shared:1;
991d9fa0 JT	138	};
	139
	140	/*
	141	* Returns:
e5cfc69a	142	* -EWOULDBLOCK iff @can_issue_io is set and would issue IO
991d9fa0 JT	143	* -ENODATA iff that mapping is not present.
	144	* 0 success
	145	*/
	146	int dm_thin_find_block(struct dm_thin_device *td, dm_block_t block,
e5cfc69a	147	int can_issue_io, struct dm_thin_lookup_result *result);
991d9fa0	148
a5d895a9 JT	149	/*
	150	* Retrieve the next run of contiguously mapped blocks. Useful for working
	151	* out where to break up IO. Returns 0 on success, < 0 on error.
	152	*/
	153	int dm_thin_find_mapped_range(struct dm_thin_device *td,
	154	dm_block_t begin, dm_block_t end,
	155	dm_block_t thin_begin, dm_block_t thin_end,
	156	dm_block_t pool_begin, bool maybe_shared);
	157
991d9fa0 JT	158	/*
	159	* Obtain an unused block.
	160	*/
	161	int dm_pool_alloc_data_block(struct dm_pool_metadata pmd, dm_block_t result);
	162
	163	/*
	164	* Insert or remove block.
	165	*/
	166	int dm_thin_insert_block(struct dm_thin_device *td, dm_block_t block,
	167	dm_block_t data_block);
	168
	169	int dm_thin_remove_block(struct dm_thin_device *td, dm_block_t block);
6550f075 JT	170	int dm_thin_remove_range(struct dm_thin_device *td,
6550f075 JT	171	dm_block_t begin, dm_block_t end);
991d9fa0 JT	172
	173	/*
	174	* Queries.
	175	*/
40db5a53 JT	176	bool dm_thin_changed_this_transaction(struct dm_thin_device *td);
40db5a53 JT	177
4d1662a3 MS	178	bool dm_pool_changed_this_transaction(struct dm_pool_metadata *pmd);
4d1662a3 MS	179
da105ed5 JT	180	bool dm_thin_aborted_changes(struct dm_thin_device *td);
da105ed5 JT	181
991d9fa0 JT	182	int dm_thin_get_highest_mapped_block(struct dm_thin_device *td,
	183	dm_block_t *highest_mapped);
	184
	185	int dm_thin_get_mapped_count(struct dm_thin_device td, dm_block_t result);
	186
	187	int dm_pool_get_free_block_count(struct dm_pool_metadata *pmd,
	188	dm_block_t *result);
	189
	190	int dm_pool_get_free_metadata_block_count(struct dm_pool_metadata *pmd,
	191	dm_block_t *result);
	192
	193	int dm_pool_get_metadata_dev_size(struct dm_pool_metadata *pmd,
	194	dm_block_t *result);
	195
991d9fa0 JT	196	int dm_pool_get_data_dev_size(struct dm_pool_metadata pmd, dm_block_t result);
991d9fa0 JT	197
19fa1a67	198	int dm_pool_block_is_used(struct dm_pool_metadata pmd, dm_block_t b, bool result);
2a0fbffb JT	199
	200	int dm_pool_inc_data_range(struct dm_pool_metadata *pmd, dm_block_t b, dm_block_t e);
	201	int dm_pool_dec_data_range(struct dm_pool_metadata *pmd, dm_block_t b, dm_block_t e);
19fa1a67	202
991d9fa0 JT	203	/*
	204	* Returns -ENOSPC if the new size is too small and already allocated
	205	* blocks would be lost.
	206	*/
	207	int dm_pool_resize_data_dev(struct dm_pool_metadata *pmd, dm_block_t new_size);
24347e95	208	int dm_pool_resize_metadata_dev(struct dm_pool_metadata *pmd, dm_block_t new_size);
991d9fa0	209
12ba58af JT	210	/*
	211	* Flicks the underlying block manager into read only mode, so you know
	212	* that nothing is changing.
	213	*/
	214	void dm_pool_metadata_read_only(struct dm_pool_metadata *pmd);
9b7aaa64	215	void dm_pool_metadata_read_write(struct dm_pool_metadata *pmd);
12ba58af	216
ac8c3f3d JT	217	int dm_pool_register_metadata_threshold(struct dm_pool_metadata *pmd,
	218	dm_block_t threshold,
	219	dm_sm_threshold_fn fn,
	220	void *context);
	221
07f2b6e0 MS	222	/*
	223	* Updates the superblock immediately.
	224	*/
	225	int dm_pool_metadata_set_needs_check(struct dm_pool_metadata *pmd);
	226	bool dm_pool_metadata_needs_check(struct dm_pool_metadata *pmd);
	227
8a01a6af JT	228	/*
	229	* Issue any prefetches that may be useful.
	230	*/
	231	void dm_pool_issue_prefetches(struct dm_pool_metadata *pmd);
	232
991d9fa0 JT	233	/----------------------------------------------------------------/
	234
	235	#endif