cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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dm-clone-metadata.h (5773B)

      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_H
      7#define DM_CLONE_METADATA_H
      8
      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_SIZE
     13
     14/*
     15 * The metadata device is currently limited in size.
     16 */
     17#define DM_CLONE_METADATA_MAX_SECTORS DM_SM_METADATA_MAX_SECTORS
     18
     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 128
     25
     26/* dm-clone metadata */
     27struct dm_clone_metadata;
     28
     29/*
     30 * Set region status to hydrated.
     31 *
     32 * @cmd: The dm-clone metadata
     33 * @region_nr: The region number
     34 *
     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 already
     41 * hydrated.
     42 *
     43 * @cmd: The dm-clone metadata
     44 * @start: Starting region number
     45 * @nr_regions: Number of regions in the range
     46 *
     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 metadata
     58 * @target_size: The target size
     59 * @region_size: The region size
     60 *
     61 * @returns: The dm-clone metadata
     62 *
     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, it
     65 * 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 for
     82 *    committing. After this is called, all subsequent metadata updates, done
     83 *    through either dm_clone_set_region_hydrated() or
     84 *    dm_clone_cond_set_range(), will be part of the **next** transaction.
     85 *
     86 * 2. dm_clone_metadata_commit(): Actually commit the current transaction to
     87 *    disk and start a new transaction.
     88 *
     89 * This allows dm-clone to flush the destination device after step (1) to
     90 * ensure that all freshly hydrated regions, for which we are updating the
     91 * metadata, are properly written to non-volatile storage and won't be lost in
     92 * 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 the
    101 * metadata to read-only, to invalidate the in-core cache and make it match the
    102 * on-disk metadata.
    103 *
    104 * WARNING: It must not be called concurrently with either
    105 * dm_clone_set_region_hydrated() or dm_clone_cond_set_range(), as it updates
    106 * the region bitmap without taking the relevant spinlock. We don't take the
    107 * 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. Both
    111 * dm_clone_set_region_hydrated() and dm_clone_cond_set_range() refuse to touch
    112 * 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 last
    123 * 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 entered
    129 * 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 >= @start
    163 */
    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 */