1 /* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
2 #ifndef _LINUX_BCACHE_H
3 #define _LINUX_BCACHE_H
6 * Bcache on disk data structures
9 #include <linux/types.h>
11 #define BITMASK(name, type, field, offset, size) \
12 static __inline__ __u64 name(const type *k) \
13 { return (k->field >> offset) & ~(~0ULL << size); } \
15 static __inline__ void SET_##name(type *k, __u64 v) \
17 k->field &= ~(~(~0ULL << size) << offset); \
18 k->field |= (v & ~(~0ULL << size)) << offset; \
21 /* Btree keys - all units are in sectors */
29 #define KEY_FIELD(name, field, offset, size) \
30 BITMASK(name, struct bkey, field, offset, size)
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); } \
36 static __inline__ void SET_##name(struct bkey *k, unsigned int i, __u64 v) \
38 k->ptr[i] &= ~(~(~0ULL << size) << offset); \
39 k->ptr[i] |= (v & ~(~0ULL << size)) << offset; \
42 #define KEY_SIZE_BITS 16
43 #define KEY_MAX_U64S 8
45 KEY_FIELD(KEY_PTRS, high, 60, 3)
46 KEY_FIELD(HEADER_SIZE, high, 58, 2)
47 KEY_FIELD(KEY_CSUM, high, 56, 2)
48 KEY_FIELD(KEY_PINNED, high, 55, 1)
49 KEY_FIELD(KEY_DIRTY, high, 36, 1)
51 KEY_FIELD(KEY_SIZE, high, 20, KEY_SIZE_BITS)
52 KEY_FIELD(KEY_INODE, high, 0, 20)
54 /* Next time I change the on disk format, KEY_OFFSET() won't be 64 bits */
56 static __inline__ __u64 KEY_OFFSET(const struct bkey *k)
61 static __inline__ void SET_KEY_OFFSET(struct bkey *k, __u64 v)
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.
71 #define KEY(inode, offset, size) \
73 .high = (1ULL << 63) | ((__u64) (size) << 20) | (inode), \
77 #define ZERO_KEY KEY(0, 0, 0)
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)
83 #define KEY_START(k) (KEY_OFFSET(k) - KEY_SIZE(k))
84 #define START_KEY(k) KEY(KEY_INODE(k), KEY_START(k), 0)
86 #define PTR_DEV_BITS 12
88 PTR_FIELD(PTR_DEV, 51, PTR_DEV_BITS)
89 PTR_FIELD(PTR_OFFSET, 8, 43)
90 PTR_FIELD(PTR_GEN, 0, 8)
92 #define PTR_CHECK_DEV ((1 << PTR_DEV_BITS) - 1)
94 #define MAKE_PTR(gen, offset, dev) \
95 ((((__u64) dev) << 51) | ((__u64) offset) << 8 | gen)
97 /* Bkey utility code */
99 static __inline__ unsigned long bkey_u64s(const struct bkey *k)
101 return (sizeof(struct bkey) / sizeof(__u64)) + KEY_PTRS(k);
104 static __inline__ unsigned long bkey_bytes(const struct bkey *k)
106 return bkey_u64s(k) * sizeof(__u64);
109 #define bkey_copy(_dest, _src) memcpy(_dest, _src, bkey_bytes(_src))
111 static __inline__ void bkey_copy_key(struct bkey *dest, const struct bkey *src)
113 SET_KEY_INODE(dest, KEY_INODE(src));
114 SET_KEY_OFFSET(dest, KEY_OFFSET(src));
117 static __inline__ struct bkey *bkey_next(const struct bkey *k)
119 __u64 *d = (void *) k;
121 return (struct bkey *) (d + bkey_u64s(k));
124 static __inline__ struct bkey *bkey_idx(const struct bkey *k, unsigned int nr_keys)
126 __u64 *d = (void *) k;
128 return (struct bkey *) (d + nr_keys);
130 /* Enough for a key with 6 pointers */
133 #define BKEY_PADDED(key) \
134 union { struct bkey key; __u64 key ## _pad[BKEY_PAD]; }
138 /* Version 0: Cache device
139 * Version 1: Backing device
140 * Version 2: Seed pointer into btree node checksum
141 * Version 3: Cache device with new UUID format
142 * Version 4: Backing device with data offset
144 #define BCACHE_SB_VERSION_CDEV 0
145 #define BCACHE_SB_VERSION_BDEV 1
146 #define BCACHE_SB_VERSION_CDEV_WITH_UUID 3
147 #define BCACHE_SB_VERSION_BDEV_WITH_OFFSET 4
148 #define BCACHE_SB_MAX_VERSION 4
152 #define SB_LABEL_SIZE 32
153 #define SB_JOURNAL_BUCKETS 256U
154 /* SB_JOURNAL_BUCKETS must be divisible by BITS_PER_LONG */
155 #define MAX_CACHES_PER_SET 8
157 #define BDEV_DATA_START_DEFAULT 16 /* sectors */
161 __u64 offset; /* sector where this sb was written */
171 __u8 label[SB_LABEL_SIZE];
180 __u64 nbuckets; /* device size */
182 __u16 block_size; /* sectors */
183 __u16 bucket_size; /* sectors */
189 /* Backing devices */
193 * block_size from the cache device section is still used by
194 * backing devices, so don't add anything here until we fix
195 * things to not need it for backing devices anymore
200 __u32 last_mount; /* time overflow in y2106 */
204 __u16 njournal_buckets;
207 __u64 d[SB_JOURNAL_BUCKETS]; /* journal buckets */
210 static __inline__ _Bool SB_IS_BDEV(const struct cache_sb *sb)
212 return sb->version == BCACHE_SB_VERSION_BDEV
213 || sb->version == BCACHE_SB_VERSION_BDEV_WITH_OFFSET;
216 BITMASK(CACHE_SYNC, struct cache_sb, flags, 0, 1);
217 BITMASK(CACHE_DISCARD, struct cache_sb, flags, 1, 1);
218 BITMASK(CACHE_REPLACEMENT, struct cache_sb, flags, 2, 3);
219 #define CACHE_REPLACEMENT_LRU 0U
220 #define CACHE_REPLACEMENT_FIFO 1U
221 #define CACHE_REPLACEMENT_RANDOM 2U
223 BITMASK(BDEV_CACHE_MODE, struct cache_sb, flags, 0, 4);
224 #define CACHE_MODE_WRITETHROUGH 0U
225 #define CACHE_MODE_WRITEBACK 1U
226 #define CACHE_MODE_WRITEAROUND 2U
227 #define CACHE_MODE_NONE 3U
228 BITMASK(BDEV_STATE, struct cache_sb, flags, 61, 2);
229 #define BDEV_STATE_NONE 0U
230 #define BDEV_STATE_CLEAN 1U
231 #define BDEV_STATE_DIRTY 2U
232 #define BDEV_STATE_STALE 3U
237 * The various other data structures have their own magic numbers, which are
238 * xored with the first part of the cache set's UUID
241 #define JSET_MAGIC 0x245235c1a3625032ULL
242 #define PSET_MAGIC 0x6750e15f87337f91ULL
243 #define BSET_MAGIC 0x90135c78b99e07f5ULL
245 static __inline__ __u64 jset_magic(struct cache_sb *sb)
247 return sb->set_magic ^ JSET_MAGIC;
250 static __inline__ __u64 pset_magic(struct cache_sb *sb)
252 return sb->set_magic ^ PSET_MAGIC;
255 static __inline__ __u64 bset_magic(struct cache_sb *sb)
257 return sb->set_magic ^ BSET_MAGIC;
263 * On disk format for a journal entry:
264 * seq is monotonically increasing; every journal entry has its own unique
267 * last_seq is the oldest journal entry that still has keys the btree hasn't
268 * flushed to disk yet.
270 * version is for on disk format changes.
273 #define BCACHE_JSET_VERSION_UUIDv1 1
274 #define BCACHE_JSET_VERSION_UUID 1 /* Always latest UUID format */
275 #define BCACHE_JSET_VERSION 1
286 BKEY_PADDED(uuid_bucket);
287 BKEY_PADDED(btree_root);
291 __u64 prio_bucket[MAX_CACHES_PER_SET];
294 struct bkey start[0];
299 /* Bucket prios/gens */
313 } __attribute((packed)) data[];
316 /* UUIDS - per backing device/flash only volume metadata */
323 __u32 first_reg; /* time overflow in y2106 */
328 /* Size of flash only volumes */
336 BITMASK(UUID_FLASH_ONLY, struct uuid_entry, flags, 0, 1);
340 /* Version 1: Seed pointer into btree node checksum
342 #define BCACHE_BSET_CSUM 1
343 #define BCACHE_BSET_VERSION 1
348 * On disk a btree node is a list/log of these; within each set the keys are
359 struct bkey start[0];
366 /* UUIDS - per backing device/flash only volume metadata */
368 struct uuid_entry_v0 {
377 #endif /* _LINUX_BCACHE_H */