/* SPDX-License-Identifier: GPL-2.0-only */
/*
* Copyright (C) 2019 Arrikto, Inc. All Rights Reserved.
*/
#ifndef DM_CLONE_METADATA_H
#define DM_CLONE_METADATA_H
#include "persistent-data/dm-block-manager.h"
#include "persistent-data/dm-space-map-metadata.h"
#define DM_CLONE_METADATA_BLOCK_SIZE DM_SM_METADATA_BLOCK_SIZE
/*
* The metadata device is currently limited in size.
*/
#define DM_CLONE_METADATA_MAX_SECTORS DM_SM_METADATA_MAX_SECTORS
/*
* A metadata device larger than 16GB triggers a warning.
*/
#define DM_CLONE_METADATA_MAX_SECTORS_WARNING (16 * (1024 * 1024 * 1024 >> SECTOR_SHIFT))
#define SPACE_MAP_ROOT_SIZE 128
/* dm-clone metadata */
struct dm_clone_metadata;
/*
* Set region status to hydrated.
*
* @cmd: The dm-clone metadata
* @region_nr: The region number
*
* This function doesn't block, so it's safe to call it from interrupt context.
*/
int dm_clone_set_region_hydrated(struct dm_clone_metadata *cmd, unsigned long region_nr);
/*
* Set status of all regions in the provided range to hydrated, if not already
* hydrated.
*
* @cmd: The dm-clone metadata
* @start: Starting region number
* @nr_regions: Number of regions in the range
*
* This function doesn't block, but since it uses spin_lock_irq()/spin_unlock_irq()
* it's NOT safe to call it from any context where interrupts are disabled, e.g.,
* from interrupt context.
*/
int dm_clone_cond_set_range(struct dm_clone_metadata *cmd, unsigned long start,
unsigned long nr_regions);
/*
* Read existing or create fresh metadata.
*
* @bdev: The device storing the metadata
* @target_size: The target size
* @region_size: The region size
*
* @returns: The dm-clone metadata
*
* This function reads the superblock of @bdev and checks if it's all zeroes.
* If it is, it formats @bdev and creates fresh metadata. If it isn't, it
* validates the metadata stored in @bdev.
*/
struct dm_clone_metadata *dm_clone_metadata_open(struct block_device *bdev,
sector_t target_size,
sector_t region_size);
/*
* Free the resources related to metadata management.
*/
void dm_clone_metadata_close(struct dm_clone_metadata *cmd);
/*
* Commit dm-clone metadata to disk.
*
* We use a two phase commit:
*
* 1. dm_clone_metadata_pre_commit(): Prepare the current transaction for
* committing. After this is called, all subsequent metadata updates, done
* through either dm_clone_set_region_hydrated() or
* dm_clone_cond_set_range(), will be part of the **next** transaction.
*
* 2. dm_clone_metadata_commit(): Actually commit the current transaction to
* disk and start a new transaction.
*
* This allows dm-clone to flush the destination device after step (1) to
* ensure that all freshly hydrated regions, for which we are updating the
* metadata, are properly written to non-volatile storage and won't be lost in
* case of a crash.
*/
int dm_clone_metadata_pre_commit(struct dm_clone_metadata *cmd);
int dm_clone_metadata_commit(struct dm_clone_metadata *cmd);
/*
* Reload the in core copy of the on-disk bitmap.
*
* This should be used after aborting a metadata transaction and setting the
* metadata to read-only, to invalidate the in-core cache and make it match the
* on-disk metadata.
*
* WARNING: It must not be called concurrently with either
* dm_clone_set_region_hydrated() or dm_clone_cond_set_range(), as it updates
* the region bitmap without taking the relevant spinlock. We don't take the
* spinlock because dm_clone_reload_in_core_bitset() does I/O, so it may block.
*
* But, it's safe to use it after calling dm_clone_metadata_set_read_only(),
* because the latter sets the metadata to read-only mode. Both
* dm_clone_set_region_hydrated() and dm_clone_cond_set_range() refuse to touch
* the region bitmap, after calling dm_clone_metadata_set_read_only().
*/
int dm_clone_reload_in_core_bitset(struct dm_clone_metadata *cmd);
/*
* Check whether dm-clone's metadata changed this transaction.
*/
bool dm_clone_changed_this_transaction(struct dm_clone_metadata *cmd);
/*
* Abort current metadata transaction and rollback metadata to the last
* committed transaction.
*/
int dm_clone_metadata_abort(struct dm_clone_metadata *cmd);
/*
* Switches metadata to a read only mode. Once read-only mode has been entered
* the following functions will return -EPERM:
*
* dm_clone_metadata_pre_commit()
* dm_clone_metadata_commit()
* dm_clone_set_region_hydrated()
* dm_clone_cond_set_range()
* dm_clone_metadata_abort()
*/
void dm_clone_metadata_set_read_only(struct dm_clone_metadata *cmd);
void dm_clone_metadata_set_read_write(struct dm_clone_metadata *cmd);
/*
* Returns true if the hydration of the destination device is finished.
*/
bool dm_clone_is_hydration_done(struct dm_clone_metadata *cmd);
/*
* Returns true if region @region_nr is hydrated.
*/
bool dm_clone_is_region_hydrated(struct dm_clone_metadata *cmd, unsigned long region_nr);
/*
* Returns true if all the regions in the range are hydrated.
*/
bool dm_clone_is_range_hydrated(struct dm_clone_metadata *cmd,
unsigned long start, unsigned long nr_regions);
/*
* Returns the number of hydrated regions.
*/
unsigned int dm_clone_nr_of_hydrated_regions(struct dm_clone_metadata *cmd);
/*
* Returns the first unhydrated region with region_nr >= @start
*/
unsigned long dm_clone_find_next_unhydrated_region(struct dm_clone_metadata *cmd,
unsigned long start);
/*
* Get the number of free metadata blocks.
*/
int dm_clone_get_free_metadata_block_count(struct dm_clone_metadata *cmd, dm_block_t *result);
/*
* Get the total number of metadata blocks.
*/
int dm_clone_get_metadata_dev_size(struct dm_clone_metadata *cmd, dm_block_t *result);
#endif /* DM_CLONE_METADATA_H */
Codebase Browser
linux