^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2) * Copyright (C) 2001-2002 Sistina Software (UK) Limited.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3) * Copyright (C) 2008 Red Hat, Inc. All rights reserved.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 4) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 5) * Device-mapper snapshot exception store.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 6) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 7) * This file is released under the GPL.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 8) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 9)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 10) #ifndef _LINUX_DM_EXCEPTION_STORE
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 11) #define _LINUX_DM_EXCEPTION_STORE
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 12)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 13) #include <linux/blkdev.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 14) #include <linux/list_bl.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 15) #include <linux/device-mapper.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 16)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 17) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 18) * The snapshot code deals with largish chunks of the disk at a
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 19) * time. Typically 32k - 512k.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 20) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 21) typedef sector_t chunk_t;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 22)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 23) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 24) * An exception is used where an old chunk of data has been
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 25) * replaced by a new one.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 26) * If chunk_t is 64 bits in size, the top 8 bits of new_chunk hold the number
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 27) * of chunks that follow contiguously. Remaining bits hold the number of the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 28) * chunk within the device.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 29) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 30) struct dm_exception {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 31) struct hlist_bl_node hash_list;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 32)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 33) chunk_t old_chunk;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 34) chunk_t new_chunk;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 35) };
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 36)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 37) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 38) * Abstraction to handle the meta/layout of exception stores (the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 39) * COW device).
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 40) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 41) struct dm_exception_store;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 42) struct dm_exception_store_type {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 43) const char *name;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 44) struct module *module;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 45)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 46) int (*ctr) (struct dm_exception_store *store, char *options);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 47)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 48) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 49) * Destroys this object when you've finished with it.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 50) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 51) void (*dtr) (struct dm_exception_store *store);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 52)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 53) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 54) * The target shouldn't read the COW device until this is
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 55) * called. As exceptions are read from the COW, they are
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 56) * reported back via the callback.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 57) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 58) int (*read_metadata) (struct dm_exception_store *store,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 59) int (*callback)(void *callback_context,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 60) chunk_t old, chunk_t new),
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 61) void *callback_context);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 62)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 63) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 64) * Find somewhere to store the next exception.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 65) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 66) int (*prepare_exception) (struct dm_exception_store *store,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 67) struct dm_exception *e);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 68)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 69) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 70) * Update the metadata with this exception.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 71) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 72) void (*commit_exception) (struct dm_exception_store *store,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 73) struct dm_exception *e, int valid,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 74) void (*callback) (void *, int success),
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 75) void *callback_context);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 76)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 77) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 78) * Returns 0 if the exception store is empty.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 79) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 80) * If there are exceptions still to be merged, sets
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 81) * *last_old_chunk and *last_new_chunk to the most recent
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 82) * still-to-be-merged chunk and returns the number of
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 83) * consecutive previous ones.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 84) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 85) int (*prepare_merge) (struct dm_exception_store *store,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 86) chunk_t *last_old_chunk, chunk_t *last_new_chunk);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 87)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 88) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 89) * Clear the last n exceptions.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 90) * nr_merged must be <= the value returned by prepare_merge.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 91) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 92) int (*commit_merge) (struct dm_exception_store *store, int nr_merged);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 93)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 94) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 95) * The snapshot is invalid, note this in the metadata.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 96) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 97) void (*drop_snapshot) (struct dm_exception_store *store);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 98)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 99) unsigned (*status) (struct dm_exception_store *store,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 100) status_type_t status, char *result,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 101) unsigned maxlen);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 102)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 103) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 104) * Return how full the snapshot is.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 105) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 106) void (*usage) (struct dm_exception_store *store,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 107) sector_t *total_sectors, sector_t *sectors_allocated,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 108) sector_t *metadata_sectors);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 109)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 110) /* For internal device-mapper use only. */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 111) struct list_head list;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 112) };
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 113)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 114) struct dm_snapshot;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 115)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 116) struct dm_exception_store {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 117) struct dm_exception_store_type *type;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 118) struct dm_snapshot *snap;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 119)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 120) /* Size of data blocks saved - must be a power of 2 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 121) unsigned chunk_size;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 122) unsigned chunk_mask;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 123) unsigned chunk_shift;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 124)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 125) void *context;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 126)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 127) bool userspace_supports_overflow;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 128) };
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 129)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 130) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 131) * Obtain the origin or cow device used by a given snapshot.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 132) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 133) struct dm_dev *dm_snap_origin(struct dm_snapshot *snap);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 134) struct dm_dev *dm_snap_cow(struct dm_snapshot *snap);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 135)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 136) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 137) * Funtions to manipulate consecutive chunks
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 138) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 139) #define DM_CHUNK_CONSECUTIVE_BITS 8
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 140) #define DM_CHUNK_NUMBER_BITS 56
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 141)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 142) static inline chunk_t dm_chunk_number(chunk_t chunk)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 143) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 144) return chunk & (chunk_t)((1ULL << DM_CHUNK_NUMBER_BITS) - 1ULL);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 145) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 146)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 147) static inline unsigned dm_consecutive_chunk_count(struct dm_exception *e)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 148) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 149) return e->new_chunk >> DM_CHUNK_NUMBER_BITS;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 150) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 151)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 152) static inline void dm_consecutive_chunk_count_inc(struct dm_exception *e)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 153) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 154) e->new_chunk += (1ULL << DM_CHUNK_NUMBER_BITS);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 155)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 156) BUG_ON(!dm_consecutive_chunk_count(e));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 157) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 158)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 159) static inline void dm_consecutive_chunk_count_dec(struct dm_exception *e)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 160) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 161) BUG_ON(!dm_consecutive_chunk_count(e));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 162)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 163) e->new_chunk -= (1ULL << DM_CHUNK_NUMBER_BITS);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 164) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 165)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 166) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 167) * Return the number of sectors in the device.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 168) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 169) static inline sector_t get_dev_size(struct block_device *bdev)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 170) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 171) return i_size_read(bdev->bd_inode) >> SECTOR_SHIFT;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 172) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 173)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 174) static inline chunk_t sector_to_chunk(struct dm_exception_store *store,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 175) sector_t sector)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 176) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 177) return sector >> store->chunk_shift;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 178) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 179)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 180) int dm_exception_store_type_register(struct dm_exception_store_type *type);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 181) int dm_exception_store_type_unregister(struct dm_exception_store_type *type);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 182)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 183) int dm_exception_store_set_chunk_size(struct dm_exception_store *store,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 184) unsigned chunk_size,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 185) char **error);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 186)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 187) int dm_exception_store_create(struct dm_target *ti, int argc, char **argv,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 188) struct dm_snapshot *snap,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 189) unsigned *args_used,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 190) struct dm_exception_store **store);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 191) void dm_exception_store_destroy(struct dm_exception_store *store);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 192)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 193) int dm_exception_store_init(void);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 194) void dm_exception_store_exit(void);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 195)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 196) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 197) * Two exception store implementations.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 198) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 199) int dm_persistent_snapshot_init(void);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 200) void dm_persistent_snapshot_exit(void);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 201)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 202) int dm_transient_snapshot_init(void);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 203) void dm_transient_snapshot_exit(void);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 204)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 205) #endif /* _LINUX_DM_EXCEPTION_STORE */
Orange Pi5 kernel
Deprecated Linux kernel 5.10.110 for OrangePi 5/5B/5+ boards
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