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)		\
12static inline __u64 name(const type *k)				\
13{ return (k->field >> offset) & ~(~0ULL << size); }		\
14								\
15static 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
23struct 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)					\
33static inline __u64 name(const struct bkey *k, unsigned int i)		\
34{ return (k->ptr[i] >> offset) & ~(~0ULL << size); }			\
35									\
36static 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
45KEY_FIELD(KEY_PTRS,	high, 60, 3)
46KEY_FIELD(__PAD0,	high, 58, 2)
47KEY_FIELD(KEY_CSUM,	high, 56, 2)
48KEY_FIELD(__PAD1,	high, 55, 1)
49KEY_FIELD(KEY_DIRTY,	high, 36, 1)
50
51KEY_FIELD(KEY_SIZE,	high, 20, KEY_SIZE_BITS)
52KEY_FIELD(KEY_INODE,	high, 0,  20)
53
54/* Next time I change the on disk format, KEY_OFFSET() won't be 64 bits */
55
56static inline __u64 KEY_OFFSET(const struct bkey *k)
57{
58	return k->low;
59}
60
61static 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
88PTR_FIELD(PTR_DEV,			51, PTR_DEV_BITS)
89PTR_FIELD(PTR_OFFSET,			8,  43)
90PTR_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
99static inline unsigned long bkey_u64s(const struct bkey *k)
100{
101	return (sizeof(struct bkey) / sizeof(__u64)) + KEY_PTRS(k);
102}
103
104static 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
112static 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
118static 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
125static 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
163struct 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 */
226struct 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
278static 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
285BITMASK(CACHE_SYNC,			struct cache_sb, flags, 0, 1);
286BITMASK(CACHE_DISCARD,			struct cache_sb, flags, 1, 1);
287BITMASK(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
292BITMASK(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
297BITMASK(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
314static inline __u64 jset_magic(struct cache_sb *sb)
315{
316	return sb->set_magic ^ JSET_MAGIC;
317}
318
319static inline __u64 pset_magic(struct cache_sb *sb)
320{
321	return sb->set_magic ^ PSET_MAGIC;
322}
323
324static 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
346struct 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		DECLARE_FLEX_ARRAY(struct bkey, start);
364		DECLARE_FLEX_ARRAY(__u64, d);
365	};
366};
367
368/* Bucket prios/gens */
369
370struct 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
387struct 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
405BITMASK(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 */
420struct bset {
421	__u64			csum;
422	__u64			magic;
423	__u64			seq;
424	__u32			version;
425	__u32			keys;
426
427	union {
428		DECLARE_FLEX_ARRAY(struct bkey, start);
429		DECLARE_FLEX_ARRAY(__u64, d);
430	};
431};
432
433/* OBSOLETE */
434
435/* UUIDS - per backing device/flash only volume metadata */
436
437struct 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