/* 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 … /* * The metadata device is currently limited in size. */ #define DM_CLONE_METADATA_MAX_SECTORS … /* * A metadata device larger than 16GB triggers a warning. */ #define DM_CLONE_METADATA_MAX_SECTORS_WARNING … #define SPACE_MAP_ROOT_SIZE … /* 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 */
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