1 /* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
2 #ifndef _LINUX_BCACHE_H
3 #define _LINUX_BCACHE_H
4
5 /*
6 * Bcache on disk data structures
7 */
8
9 #include <linux/types.h>
10
11 #define BITMASK(name, type, field, offset, size) \
12 static inline __u64 name(const type *k) \
13 { return (k->field >> offset) & ~(~0ULL << size); } \
14 \
15 static inline void SET_##name(type *k, __u64 v) \
16 { \
17 k->field &= ~(~(~0ULL << size) << offset); \
18 k->field |= (v & ~(~0ULL << size)) << offset; \
19 }
20
21 /* Btree keys - all units are in sectors */
22
23 struct bkey {
24 __u64 high;
25 __u64 low;
26 __u64 ptr[];
27 };
28
29 #define KEY_FIELD(name, field, offset, size) \
30 BITMASK(name, struct bkey, field, offset, size)
31
32 #define PTR_FIELD(name, offset, size) \
33 static inline __u64 name(const struct bkey *k, unsigned int i) \
34 { return (k->ptr[i] >> offset) & ~(~0ULL << size); } \
35 \
36 static inline void SET_##name(struct bkey *k, unsigned int i, __u64 v) \
37 { \
38 k->ptr[i] &= ~(~(~0ULL << size) << offset); \
39 k->ptr[i] |= (v & ~(~0ULL << size)) << offset; \
40 }
41
42 #define KEY_SIZE_BITS 16
43 #define KEY_MAX_U64S 8
44
45 KEY_FIELD(KEY_PTRS, high, 60, 3)
46 KEY_FIELD(__PAD0, high, 58, 2)
47 KEY_FIELD(KEY_CSUM, high, 56, 2)
48 KEY_FIELD(__PAD1, high, 55, 1)
49 KEY_FIELD(KEY_DIRTY, high, 36, 1)
50
51 KEY_FIELD(KEY_SIZE, high, 20, KEY_SIZE_BITS)
52 KEY_FIELD(KEY_INODE, high, 0, 20)
53
54 /* Next time I change the on disk format, KEY_OFFSET() won't be 64 bits */
55
KEY_OFFSET(const struct bkey * k)56 static inline __u64 KEY_OFFSET(const struct bkey *k)
57 {
58 return k->low;
59 }
60
SET_KEY_OFFSET(struct bkey * k,__u64 v)61 static inline void SET_KEY_OFFSET(struct bkey *k, __u64 v)
62 {
63 k->low = v;
64 }
65
66 /*
67 * The high bit being set is a relic from when we used it to do binary
68 * searches - it told you where a key started. It's not used anymore,
69 * and can probably be safely dropped.
70 */
71 #define KEY(inode, offset, size) \
72 ((struct bkey) { \
73 .high = (1ULL << 63) | ((__u64) (size) << 20) | (inode), \
74 .low = (offset) \
75 })
76
77 #define ZERO_KEY KEY(0, 0, 0)
78
79 #define MAX_KEY_INODE (~(~0 << 20))
80 #define MAX_KEY_OFFSET (~0ULL >> 1)
81 #define MAX_KEY KEY(MAX_KEY_INODE, MAX_KEY_OFFSET, 0)
82
83 #define KEY_START(k) (KEY_OFFSET(k) - KEY_SIZE(k))
84 #define START_KEY(k) KEY(KEY_INODE(k), KEY_START(k), 0)
85
86 #define PTR_DEV_BITS 12
87
88 PTR_FIELD(PTR_DEV, 51, PTR_DEV_BITS)
89 PTR_FIELD(PTR_OFFSET, 8, 43)
90 PTR_FIELD(PTR_GEN, 0, 8)
91
92 #define PTR_CHECK_DEV ((1 << PTR_DEV_BITS) - 1)
93
94 #define MAKE_PTR(gen, offset, dev) \
95 ((((__u64) dev) << 51) | ((__u64) offset) << 8 | gen)
96
97 /* Bkey utility code */
98
bkey_u64s(const struct bkey * k)99 static inline unsigned long bkey_u64s(const struct bkey *k)
100 {
101 return (sizeof(struct bkey) / sizeof(__u64)) + KEY_PTRS(k);
102 }
103
bkey_bytes(const struct bkey * k)104 static inline unsigned long bkey_bytes(const struct bkey *k)
105 {
106 return bkey_u64s(k) * sizeof(__u64);
107 }
108
109 #define bkey_copy(_dest, _src) unsafe_memcpy(_dest, _src, bkey_bytes(_src), \
110 /* bkey is always padded */)
111
bkey_copy_key(struct bkey * dest,const struct bkey * src)112 static inline void bkey_copy_key(struct bkey *dest, const struct bkey *src)
113 {
114 SET_KEY_INODE(dest, KEY_INODE(src));
115 SET_KEY_OFFSET(dest, KEY_OFFSET(src));
116 }
117
bkey_next(const struct bkey * k)118 static inline struct bkey *bkey_next(const struct bkey *k)
119 {
120 __u64 *d = (void *) k;
121
122 return (struct bkey *) (d + bkey_u64s(k));
123 }
124
bkey_idx(const struct bkey * k,unsigned int nr_keys)125 static inline struct bkey *bkey_idx(const struct bkey *k, unsigned int nr_keys)
126 {
127 __u64 *d = (void *) k;
128
129 return (struct bkey *) (d + nr_keys);
130 }
131 /* Enough for a key with 6 pointers */
132 #define BKEY_PAD 8
133
134 #define BKEY_PADDED(key) \
135 union { struct bkey key; __u64 key ## _pad[BKEY_PAD]; }
136
137 /* Superblock */
138
139 /* Version 0: Cache device
140 * Version 1: Backing device
141 * Version 2: Seed pointer into btree node checksum
142 * Version 3: Cache device with new UUID format
143 * Version 4: Backing device with data offset
144 */
145 #define BCACHE_SB_VERSION_CDEV 0
146 #define BCACHE_SB_VERSION_BDEV 1
147 #define BCACHE_SB_VERSION_CDEV_WITH_UUID 3
148 #define BCACHE_SB_VERSION_BDEV_WITH_OFFSET 4
149 #define BCACHE_SB_VERSION_CDEV_WITH_FEATURES 5
150 #define BCACHE_SB_VERSION_BDEV_WITH_FEATURES 6
151 #define BCACHE_SB_MAX_VERSION 6
152
153 #define SB_SECTOR 8
154 #define SB_OFFSET (SB_SECTOR << SECTOR_SHIFT)
155 #define SB_SIZE 4096
156 #define SB_LABEL_SIZE 32
157 #define SB_JOURNAL_BUCKETS 256U
158 /* SB_JOURNAL_BUCKETS must be divisible by BITS_PER_LONG */
159 #define MAX_CACHES_PER_SET 8
160
161 #define BDEV_DATA_START_DEFAULT 16 /* sectors */
162
163 struct cache_sb_disk {
164 __le64 csum;
165 __le64 offset; /* sector where this sb was written */
166 __le64 version;
167
168 __u8 magic[16];
169
170 __u8 uuid[16];
171 union {
172 __u8 set_uuid[16];
173 __le64 set_magic;
174 };
175 __u8 label[SB_LABEL_SIZE];
176
177 __le64 flags;
178 __le64 seq;
179
180 __le64 feature_compat;
181 __le64 feature_incompat;
182 __le64 feature_ro_compat;
183
184 __le64 pad[5];
185
186 union {
187 struct {
188 /* Cache devices */
189 __le64 nbuckets; /* device size */
190
191 __le16 block_size; /* sectors */
192 __le16 bucket_size; /* sectors */
193
194 __le16 nr_in_set;
195 __le16 nr_this_dev;
196 };
197 struct {
198 /* Backing devices */
199 __le64 data_offset;
200
201 /*
202 * block_size from the cache device section is still used by
203 * backing devices, so don't add anything here until we fix
204 * things to not need it for backing devices anymore
205 */
206 };
207 };
208
209 __le32 last_mount; /* time overflow in y2106 */
210
211 __le16 first_bucket;
212 union {
213 __le16 njournal_buckets;
214 __le16 keys;
215 };
216 __le64 d[SB_JOURNAL_BUCKETS]; /* journal buckets */
217 __le16 obso_bucket_size_hi; /* obsoleted */
218 };
219
220 /*
221 * This is for in-memory bcache super block.
222 * NOTE: cache_sb is NOT exactly mapping to cache_sb_disk, the member
223 * size, ordering and even whole struct size may be different
224 * from cache_sb_disk.
225 */
226 struct cache_sb {
227 __u64 offset; /* sector where this sb was written */
228 __u64 version;
229
230 __u8 magic[16];
231
232 __u8 uuid[16];
233 union {
234 __u8 set_uuid[16];
235 __u64 set_magic;
236 };
237 __u8 label[SB_LABEL_SIZE];
238
239 __u64 flags;
240 __u64 seq;
241
242 __u64 feature_compat;
243 __u64 feature_incompat;
244 __u64 feature_ro_compat;
245
246 union {
247 struct {
248 /* Cache devices */
249 __u64 nbuckets; /* device size */
250
251 __u16 block_size; /* sectors */
252 __u16 nr_in_set;
253 __u16 nr_this_dev;
254 __u32 bucket_size; /* sectors */
255 };
256 struct {
257 /* Backing devices */
258 __u64 data_offset;
259
260 /*
261 * block_size from the cache device section is still used by
262 * backing devices, so don't add anything here until we fix
263 * things to not need it for backing devices anymore
264 */
265 };
266 };
267
268 __u32 last_mount; /* time overflow in y2106 */
269
270 __u16 first_bucket;
271 union {
272 __u16 njournal_buckets;
273 __u16 keys;
274 };
275 __u64 d[SB_JOURNAL_BUCKETS]; /* journal buckets */
276 };
277
SB_IS_BDEV(const struct cache_sb * sb)278 static inline _Bool SB_IS_BDEV(const struct cache_sb *sb)
279 {
280 return sb->version == BCACHE_SB_VERSION_BDEV
281 || sb->version == BCACHE_SB_VERSION_BDEV_WITH_OFFSET
282 || sb->version == BCACHE_SB_VERSION_BDEV_WITH_FEATURES;
283 }
284
285 BITMASK(CACHE_SYNC, struct cache_sb, flags, 0, 1);
286 BITMASK(CACHE_DISCARD, struct cache_sb, flags, 1, 1);
287 BITMASK(CACHE_REPLACEMENT, struct cache_sb, flags, 2, 3);
288 #define CACHE_REPLACEMENT_LRU 0U
289 #define CACHE_REPLACEMENT_FIFO 1U
290 #define CACHE_REPLACEMENT_RANDOM 2U
291
292 BITMASK(BDEV_CACHE_MODE, struct cache_sb, flags, 0, 4);
293 #define CACHE_MODE_WRITETHROUGH 0U
294 #define CACHE_MODE_WRITEBACK 1U
295 #define CACHE_MODE_WRITEAROUND 2U
296 #define CACHE_MODE_NONE 3U
297 BITMASK(BDEV_STATE, struct cache_sb, flags, 61, 2);
298 #define BDEV_STATE_NONE 0U
299 #define BDEV_STATE_CLEAN 1U
300 #define BDEV_STATE_DIRTY 2U
301 #define BDEV_STATE_STALE 3U
302
303 /*
304 * Magic numbers
305 *
306 * The various other data structures have their own magic numbers, which are
307 * xored with the first part of the cache set's UUID
308 */
309
310 #define JSET_MAGIC 0x245235c1a3625032ULL
311 #define PSET_MAGIC 0x6750e15f87337f91ULL
312 #define BSET_MAGIC 0x90135c78b99e07f5ULL
313
jset_magic(struct cache_sb * sb)314 static inline __u64 jset_magic(struct cache_sb *sb)
315 {
316 return sb->set_magic ^ JSET_MAGIC;
317 }
318
pset_magic(struct cache_sb * sb)319 static inline __u64 pset_magic(struct cache_sb *sb)
320 {
321 return sb->set_magic ^ PSET_MAGIC;
322 }
323
bset_magic(struct cache_sb * sb)324 static inline __u64 bset_magic(struct cache_sb *sb)
325 {
326 return sb->set_magic ^ BSET_MAGIC;
327 }
328
329 /*
330 * Journal
331 *
332 * On disk format for a journal entry:
333 * seq is monotonically increasing; every journal entry has its own unique
334 * sequence number.
335 *
336 * last_seq is the oldest journal entry that still has keys the btree hasn't
337 * flushed to disk yet.
338 *
339 * version is for on disk format changes.
340 */
341
342 #define BCACHE_JSET_VERSION_UUIDv1 1
343 #define BCACHE_JSET_VERSION_UUID 1 /* Always latest UUID format */
344 #define BCACHE_JSET_VERSION 1
345
346 struct jset {
347 __u64 csum;
348 __u64 magic;
349 __u64 seq;
350 __u32 version;
351 __u32 keys;
352
353 __u64 last_seq;
354
355 BKEY_PADDED(uuid_bucket);
356 BKEY_PADDED(btree_root);
357 __u16 btree_level;
358 __u16 pad[3];
359
360 __u64 prio_bucket[MAX_CACHES_PER_SET];
361
362 union {
363 struct bkey start[0];
364 __u64 d[0];
365 };
366 };
367
368 /* Bucket prios/gens */
369
370 struct prio_set {
371 __u64 csum;
372 __u64 magic;
373 __u64 seq;
374 __u32 version;
375 __u32 pad;
376
377 __u64 next_bucket;
378
379 struct bucket_disk {
380 __u16 prio;
381 __u8 gen;
382 } __attribute((packed)) data[];
383 };
384
385 /* UUIDS - per backing device/flash only volume metadata */
386
387 struct uuid_entry {
388 union {
389 struct {
390 __u8 uuid[16];
391 __u8 label[32];
392 __u32 first_reg; /* time overflow in y2106 */
393 __u32 last_reg;
394 __u32 invalidated;
395
396 __u32 flags;
397 /* Size of flash only volumes */
398 __u64 sectors;
399 };
400
401 __u8 pad[128];
402 };
403 };
404
405 BITMASK(UUID_FLASH_ONLY, struct uuid_entry, flags, 0, 1);
406
407 /* Btree nodes */
408
409 /* Version 1: Seed pointer into btree node checksum
410 */
411 #define BCACHE_BSET_CSUM 1
412 #define BCACHE_BSET_VERSION 1
413
414 /*
415 * Btree nodes
416 *
417 * On disk a btree node is a list/log of these; within each set the keys are
418 * sorted
419 */
420 struct bset {
421 __u64 csum;
422 __u64 magic;
423 __u64 seq;
424 __u32 version;
425 __u32 keys;
426
427 union {
428 struct bkey start[0];
429 __u64 d[0];
430 };
431 };
432
433 /* OBSOLETE */
434
435 /* UUIDS - per backing device/flash only volume metadata */
436
437 struct uuid_entry_v0 {
438 __u8 uuid[16];
439 __u8 label[32];
440 __u32 first_reg;
441 __u32 last_reg;
442 __u32 invalidated;
443 __u32 pad;
444 };
445
446 #endif /* _LINUX_BCACHE_H */
447