/*
* 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"
#define THIN_METADATA_BLOCK_SIZE 4096
/*
* The metadata device is currently limited in size.
*
* We have one block of index, which can hold 255 index entries. Each
* index entry contains allocation info about 16k metadata blocks.
*/
#define THIN_METADATA_MAX_SECTORS (255 * (1 << 14) * (THIN_METADATA_BLOCK_SIZE / (1 << SECTOR_SHIFT)))
/*
* A metadata device larger than 16GB triggers a warning.
*/
#define THIN_METADATA_MAX_SECTORS_WARNING (16 * (1024 * 1024 * 1024 >> SECTOR_SHIFT))
/*----------------------------------------------------------------*/
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;
unsigned shared:1;
};
/*
* Returns:
* -EWOULDBLOCK iff @can_block is set and would block.
* -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_block, struct dm_thin_lookup_result *result);
/*
* 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);
/*
* Queries.
*/
bool dm_thin_changed_this_transaction(struct dm_thin_device *td);
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_block_size(struct dm_pool_metadata *pmd, sector_t *result);
int dm_pool_get_data_dev_size(struct dm_pool_metadata *pmd, dm_block_t *result);
/*
* 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);
/*
* 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);
/*----------------------------------------------------------------*/
#endif
