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1/* SPDX-License-Identifier: GPL-2.0-only */2/*3 * Copyright (C) 2019 Arrikto, Inc. All Rights Reserved.4 */5 6#ifndef DM_CLONE_METADATA_H7#define DM_CLONE_METADATA_H8 9#include "persistent-data/dm-block-manager.h"10#include "persistent-data/dm-space-map-metadata.h"11 12#define DM_CLONE_METADATA_BLOCK_SIZE DM_SM_METADATA_BLOCK_SIZE13 14/*15 * The metadata device is currently limited in size.16 */17#define DM_CLONE_METADATA_MAX_SECTORS DM_SM_METADATA_MAX_SECTORS18 19/*20 * A metadata device larger than 16GB triggers a warning.21 */22#define DM_CLONE_METADATA_MAX_SECTORS_WARNING (16 * (1024 * 1024 * 1024 >> SECTOR_SHIFT))23 24#define SPACE_MAP_ROOT_SIZE 12825 26/* dm-clone metadata */27struct dm_clone_metadata;28 29/*30 * Set region status to hydrated.31 *32 * @cmd: The dm-clone metadata33 * @region_nr: The region number34 *35 * This function doesn't block, so it's safe to call it from interrupt context.36 */37int dm_clone_set_region_hydrated(struct dm_clone_metadata *cmd, unsigned long region_nr);38 39/*40 * Set status of all regions in the provided range to hydrated, if not already41 * hydrated.42 *43 * @cmd: The dm-clone metadata44 * @start: Starting region number45 * @nr_regions: Number of regions in the range46 *47 * This function doesn't block, but since it uses spin_lock_irq()/spin_unlock_irq()48 * it's NOT safe to call it from any context where interrupts are disabled, e.g.,49 * from interrupt context.50 */51int dm_clone_cond_set_range(struct dm_clone_metadata *cmd, unsigned long start,52 unsigned long nr_regions);53 54/*55 * Read existing or create fresh metadata.56 *57 * @bdev: The device storing the metadata58 * @target_size: The target size59 * @region_size: The region size60 *61 * @returns: The dm-clone metadata62 *63 * This function reads the superblock of @bdev and checks if it's all zeroes.64 * If it is, it formats @bdev and creates fresh metadata. If it isn't, it65 * validates the metadata stored in @bdev.66 */67struct dm_clone_metadata *dm_clone_metadata_open(struct block_device *bdev,68 sector_t target_size,69 sector_t region_size);70 71/*72 * Free the resources related to metadata management.73 */74void dm_clone_metadata_close(struct dm_clone_metadata *cmd);75 76/*77 * Commit dm-clone metadata to disk.78 *79 * We use a two phase commit:80 *81 * 1. dm_clone_metadata_pre_commit(): Prepare the current transaction for82 * committing. After this is called, all subsequent metadata updates, done83 * through either dm_clone_set_region_hydrated() or84 * dm_clone_cond_set_range(), will be part of the **next** transaction.85 *86 * 2. dm_clone_metadata_commit(): Actually commit the current transaction to87 * disk and start a new transaction.88 *89 * This allows dm-clone to flush the destination device after step (1) to90 * ensure that all freshly hydrated regions, for which we are updating the91 * metadata, are properly written to non-volatile storage and won't be lost in92 * case of a crash.93 */94int dm_clone_metadata_pre_commit(struct dm_clone_metadata *cmd);95int dm_clone_metadata_commit(struct dm_clone_metadata *cmd);96 97/*98 * Reload the in core copy of the on-disk bitmap.99 *100 * This should be used after aborting a metadata transaction and setting the101 * metadata to read-only, to invalidate the in-core cache and make it match the102 * on-disk metadata.103 *104 * WARNING: It must not be called concurrently with either105 * dm_clone_set_region_hydrated() or dm_clone_cond_set_range(), as it updates106 * the region bitmap without taking the relevant spinlock. We don't take the107 * spinlock because dm_clone_reload_in_core_bitset() does I/O, so it may block.108 *109 * But, it's safe to use it after calling dm_clone_metadata_set_read_only(),110 * because the latter sets the metadata to read-only mode. Both111 * dm_clone_set_region_hydrated() and dm_clone_cond_set_range() refuse to touch112 * the region bitmap, after calling dm_clone_metadata_set_read_only().113 */114int dm_clone_reload_in_core_bitset(struct dm_clone_metadata *cmd);115 116/*117 * Check whether dm-clone's metadata changed this transaction.118 */119bool dm_clone_changed_this_transaction(struct dm_clone_metadata *cmd);120 121/*122 * Abort current metadata transaction and rollback metadata to the last123 * committed transaction.124 */125int dm_clone_metadata_abort(struct dm_clone_metadata *cmd);126 127/*128 * Switches metadata to a read only mode. Once read-only mode has been entered129 * the following functions will return -EPERM:130 *131 * dm_clone_metadata_pre_commit()132 * dm_clone_metadata_commit()133 * dm_clone_set_region_hydrated()134 * dm_clone_cond_set_range()135 * dm_clone_metadata_abort()136 */137void dm_clone_metadata_set_read_only(struct dm_clone_metadata *cmd);138void dm_clone_metadata_set_read_write(struct dm_clone_metadata *cmd);139 140/*141 * Returns true if the hydration of the destination device is finished.142 */143bool dm_clone_is_hydration_done(struct dm_clone_metadata *cmd);144 145/*146 * Returns true if region @region_nr is hydrated.147 */148bool dm_clone_is_region_hydrated(struct dm_clone_metadata *cmd, unsigned long region_nr);149 150/*151 * Returns true if all the regions in the range are hydrated.152 */153bool dm_clone_is_range_hydrated(struct dm_clone_metadata *cmd,154 unsigned long start, unsigned long nr_regions);155 156/*157 * Returns the number of hydrated regions.158 */159unsigned int dm_clone_nr_of_hydrated_regions(struct dm_clone_metadata *cmd);160 161/*162 * Returns the first unhydrated region with region_nr >= @start163 */164unsigned long dm_clone_find_next_unhydrated_region(struct dm_clone_metadata *cmd,165 unsigned long start);166 167/*168 * Get the number of free metadata blocks.169 */170int dm_clone_get_free_metadata_block_count(struct dm_clone_metadata *cmd, dm_block_t *result);171 172/*173 * Get the total number of metadata blocks.174 */175int dm_clone_get_metadata_dev_size(struct dm_clone_metadata *cmd, dm_block_t *result);176 177#endif /* DM_CLONE_METADATA_H */178