xref: /linux/fs/bcachefs/bcachefs_format.h (revision 08df80a3c51674ab73ae770885a383ca553fbbbf)
1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _BCACHEFS_FORMAT_H
3 #define _BCACHEFS_FORMAT_H
4 
5 /*
6  * bcachefs on disk data structures
7  *
8  * OVERVIEW:
9  *
10  * There are three main types of on disk data structures in bcachefs (this is
11  * reduced from 5 in bcache)
12  *
13  *  - superblock
14  *  - journal
15  *  - btree
16  *
17  * The btree is the primary structure; most metadata exists as keys in the
18  * various btrees. There are only a small number of btrees, they're not
19  * sharded - we have one btree for extents, another for inodes, et cetera.
20  *
21  * SUPERBLOCK:
22  *
23  * The superblock contains the location of the journal, the list of devices in
24  * the filesystem, and in general any metadata we need in order to decide
25  * whether we can start a filesystem or prior to reading the journal/btree
26  * roots.
27  *
28  * The superblock is extensible, and most of the contents of the superblock are
29  * in variable length, type tagged fields; see struct bch_sb_field.
30  *
31  * Backup superblocks do not reside in a fixed location; also, superblocks do
32  * not have a fixed size. To locate backup superblocks we have struct
33  * bch_sb_layout; we store a copy of this inside every superblock, and also
34  * before the first superblock.
35  *
36  * JOURNAL:
37  *
38  * The journal primarily records btree updates in the order they occurred;
39  * journal replay consists of just iterating over all the keys in the open
40  * journal entries and re-inserting them into the btrees.
41  *
42  * The journal also contains entry types for the btree roots, and blacklisted
43  * journal sequence numbers (see journal_seq_blacklist.c).
44  *
45  * BTREE:
46  *
47  * bcachefs btrees are copy on write b+ trees, where nodes are big (typically
48  * 128k-256k) and log structured. We use struct btree_node for writing the first
49  * entry in a given node (offset 0), and struct btree_node_entry for all
50  * subsequent writes.
51  *
52  * After the header, btree node entries contain a list of keys in sorted order.
53  * Values are stored inline with the keys; since values are variable length (and
54  * keys effectively are variable length too, due to packing) we can't do random
55  * access without building up additional in memory tables in the btree node read
56  * path.
57  *
58  * BTREE KEYS (struct bkey):
59  *
60  * The various btrees share a common format for the key - so as to avoid
61  * switching in fastpath lookup/comparison code - but define their own
62  * structures for the key values.
63  *
64  * The size of a key/value pair is stored as a u8 in units of u64s, so the max
65  * size is just under 2k. The common part also contains a type tag for the
66  * value, and a format field indicating whether the key is packed or not (and
67  * also meant to allow adding new key fields in the future, if desired).
68  *
69  * bkeys, when stored within a btree node, may also be packed. In that case, the
70  * bkey_format in that node is used to unpack it. Packed bkeys mean that we can
71  * be generous with field sizes in the common part of the key format (64 bit
72  * inode number, 64 bit offset, 96 bit version field, etc.) for negligible cost.
73  */
74 
75 #include <asm/types.h>
76 #include <asm/byteorder.h>
77 #include <linux/kernel.h>
78 #include <linux/uuid.h>
79 #include "vstructs.h"
80 
81 #ifdef __KERNEL__
82 typedef uuid_t __uuid_t;
83 #endif
84 
85 #define BITMASK(name, type, field, offset, end)				\
86 static const __maybe_unused unsigned	name##_OFFSET = offset;		\
87 static const __maybe_unused unsigned	name##_BITS = (end - offset);	\
88 									\
89 static inline __u64 name(const type *k)					\
90 {									\
91 	return (k->field >> offset) & ~(~0ULL << (end - offset));	\
92 }									\
93 									\
94 static inline void SET_##name(type *k, __u64 v)				\
95 {									\
96 	k->field &= ~(~(~0ULL << (end - offset)) << offset);		\
97 	k->field |= (v & ~(~0ULL << (end - offset))) << offset;		\
98 }
99 
100 #define LE_BITMASK(_bits, name, type, field, offset, end)		\
101 static const __maybe_unused unsigned	name##_OFFSET = offset;		\
102 static const __maybe_unused unsigned	name##_BITS = (end - offset);	\
103 static const __maybe_unused __u##_bits	name##_MAX = (1ULL << (end - offset)) - 1;\
104 									\
105 static inline __u64 name(const type *k)					\
106 {									\
107 	return (__le##_bits##_to_cpu(k->field) >> offset) &		\
108 		~(~0ULL << (end - offset));				\
109 }									\
110 									\
111 static inline void SET_##name(type *k, __u64 v)				\
112 {									\
113 	__u##_bits new = __le##_bits##_to_cpu(k->field);		\
114 									\
115 	new &= ~(~(~0ULL << (end - offset)) << offset);			\
116 	new |= (v & ~(~0ULL << (end - offset))) << offset;		\
117 	k->field = __cpu_to_le##_bits(new);				\
118 }
119 
120 #define LE16_BITMASK(n, t, f, o, e)	LE_BITMASK(16, n, t, f, o, e)
121 #define LE32_BITMASK(n, t, f, o, e)	LE_BITMASK(32, n, t, f, o, e)
122 #define LE64_BITMASK(n, t, f, o, e)	LE_BITMASK(64, n, t, f, o, e)
123 
124 struct bkey_format {
125 	__u8		key_u64s;
126 	__u8		nr_fields;
127 	/* One unused slot for now: */
128 	__u8		bits_per_field[6];
129 	__le64		field_offset[6];
130 };
131 
132 /* Btree keys - all units are in sectors */
133 
134 struct bpos {
135 	/*
136 	 * Word order matches machine byte order - btree code treats a bpos as a
137 	 * single large integer, for search/comparison purposes
138 	 *
139 	 * Note that wherever a bpos is embedded in another on disk data
140 	 * structure, it has to be byte swabbed when reading in metadata that
141 	 * wasn't written in native endian order:
142 	 */
143 #if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
144 	__u32		snapshot;
145 	__u64		offset;
146 	__u64		inode;
147 #elif __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
148 	__u64		inode;
149 	__u64		offset;		/* Points to end of extent - sectors */
150 	__u32		snapshot;
151 #else
152 #error edit for your odd byteorder.
153 #endif
154 } __packed
155 #if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
156 __aligned(4)
157 #endif
158 ;
159 
160 #define KEY_INODE_MAX			((__u64)~0ULL)
161 #define KEY_OFFSET_MAX			((__u64)~0ULL)
162 #define KEY_SNAPSHOT_MAX		((__u32)~0U)
163 #define KEY_SIZE_MAX			((__u32)~0U)
164 
165 static inline struct bpos SPOS(__u64 inode, __u64 offset, __u32 snapshot)
166 {
167 	return (struct bpos) {
168 		.inode		= inode,
169 		.offset		= offset,
170 		.snapshot	= snapshot,
171 	};
172 }
173 
174 #define POS_MIN				SPOS(0, 0, 0)
175 #define POS_MAX				SPOS(KEY_INODE_MAX, KEY_OFFSET_MAX, 0)
176 #define SPOS_MAX			SPOS(KEY_INODE_MAX, KEY_OFFSET_MAX, KEY_SNAPSHOT_MAX)
177 #define POS(_inode, _offset)		SPOS(_inode, _offset, 0)
178 
179 /* Empty placeholder struct, for container_of() */
180 struct bch_val {
181 	__u64		__nothing[0];
182 };
183 
184 struct bversion {
185 #if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
186 	__u64		lo;
187 	__u32		hi;
188 #elif __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
189 	__u32		hi;
190 	__u64		lo;
191 #endif
192 } __packed __aligned(4);
193 
194 struct bkey {
195 	/* Size of combined key and value, in u64s */
196 	__u8		u64s;
197 
198 	/* Format of key (0 for format local to btree node) */
199 #if defined(__LITTLE_ENDIAN_BITFIELD)
200 	__u8		format:7,
201 			needs_whiteout:1;
202 #elif defined (__BIG_ENDIAN_BITFIELD)
203 	__u8		needs_whiteout:1,
204 			format:7;
205 #else
206 #error edit for your odd byteorder.
207 #endif
208 
209 	/* Type of the value */
210 	__u8		type;
211 
212 #if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
213 	__u8		pad[1];
214 
215 	struct bversion	version;
216 	__u32		size;		/* extent size, in sectors */
217 	struct bpos	p;
218 #elif __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
219 	struct bpos	p;
220 	__u32		size;		/* extent size, in sectors */
221 	struct bversion	version;
222 
223 	__u8		pad[1];
224 #endif
225 } __packed __aligned(8);
226 
227 struct bkey_packed {
228 	__u64		_data[0];
229 
230 	/* Size of combined key and value, in u64s */
231 	__u8		u64s;
232 
233 	/* Format of key (0 for format local to btree node) */
234 
235 	/*
236 	 * XXX: next incompat on disk format change, switch format and
237 	 * needs_whiteout - bkey_packed() will be cheaper if format is the high
238 	 * bits of the bitfield
239 	 */
240 #if defined(__LITTLE_ENDIAN_BITFIELD)
241 	__u8		format:7,
242 			needs_whiteout:1;
243 #elif defined (__BIG_ENDIAN_BITFIELD)
244 	__u8		needs_whiteout:1,
245 			format:7;
246 #endif
247 
248 	/* Type of the value */
249 	__u8		type;
250 	__u8		key_start[0];
251 
252 	/*
253 	 * We copy bkeys with struct assignment in various places, and while
254 	 * that shouldn't be done with packed bkeys we can't disallow it in C,
255 	 * and it's legal to cast a bkey to a bkey_packed  - so padding it out
256 	 * to the same size as struct bkey should hopefully be safest.
257 	 */
258 	__u8		pad[sizeof(struct bkey) - 3];
259 } __packed __aligned(8);
260 
261 typedef struct {
262 	__le64			lo;
263 	__le64			hi;
264 } bch_le128;
265 
266 #define BKEY_U64s			(sizeof(struct bkey) / sizeof(__u64))
267 #define BKEY_U64s_MAX			U8_MAX
268 #define BKEY_VAL_U64s_MAX		(BKEY_U64s_MAX - BKEY_U64s)
269 
270 #define KEY_PACKED_BITS_START		24
271 
272 #define KEY_FORMAT_LOCAL_BTREE		0
273 #define KEY_FORMAT_CURRENT		1
274 
275 enum bch_bkey_fields {
276 	BKEY_FIELD_INODE,
277 	BKEY_FIELD_OFFSET,
278 	BKEY_FIELD_SNAPSHOT,
279 	BKEY_FIELD_SIZE,
280 	BKEY_FIELD_VERSION_HI,
281 	BKEY_FIELD_VERSION_LO,
282 	BKEY_NR_FIELDS,
283 };
284 
285 #define bkey_format_field(name, field)					\
286 	[BKEY_FIELD_##name] = (sizeof(((struct bkey *) NULL)->field) * 8)
287 
288 #define BKEY_FORMAT_CURRENT						\
289 ((struct bkey_format) {							\
290 	.key_u64s	= BKEY_U64s,					\
291 	.nr_fields	= BKEY_NR_FIELDS,				\
292 	.bits_per_field = {						\
293 		bkey_format_field(INODE,	p.inode),		\
294 		bkey_format_field(OFFSET,	p.offset),		\
295 		bkey_format_field(SNAPSHOT,	p.snapshot),		\
296 		bkey_format_field(SIZE,		size),			\
297 		bkey_format_field(VERSION_HI,	version.hi),		\
298 		bkey_format_field(VERSION_LO,	version.lo),		\
299 	},								\
300 })
301 
302 /* bkey with inline value */
303 struct bkey_i {
304 	__u64			_data[0];
305 
306 	struct bkey	k;
307 	struct bch_val	v;
308 };
309 
310 #define POS_KEY(_pos)							\
311 ((struct bkey) {							\
312 	.u64s		= BKEY_U64s,					\
313 	.format		= KEY_FORMAT_CURRENT,				\
314 	.p		= _pos,						\
315 })
316 
317 #define KEY(_inode, _offset, _size)					\
318 ((struct bkey) {							\
319 	.u64s		= BKEY_U64s,					\
320 	.format		= KEY_FORMAT_CURRENT,				\
321 	.p		= POS(_inode, _offset),				\
322 	.size		= _size,					\
323 })
324 
325 static inline void bkey_init(struct bkey *k)
326 {
327 	*k = KEY(0, 0, 0);
328 }
329 
330 #define bkey_bytes(_k)		((_k)->u64s * sizeof(__u64))
331 
332 #define __BKEY_PADDED(key, pad)					\
333 	struct bkey_i key; __u64 key ## _pad[pad]
334 
335 /*
336  * - DELETED keys are used internally to mark keys that should be ignored but
337  *   override keys in composition order.  Their version number is ignored.
338  *
339  * - DISCARDED keys indicate that the data is all 0s because it has been
340  *   discarded. DISCARDs may have a version; if the version is nonzero the key
341  *   will be persistent, otherwise the key will be dropped whenever the btree
342  *   node is rewritten (like DELETED keys).
343  *
344  * - ERROR: any read of the data returns a read error, as the data was lost due
345  *   to a failing device. Like DISCARDED keys, they can be removed (overridden)
346  *   by new writes or cluster-wide GC. Node repair can also overwrite them with
347  *   the same or a more recent version number, but not with an older version
348  *   number.
349  *
350  * - WHITEOUT: for hash table btrees
351  */
352 #define BCH_BKEY_TYPES()				\
353 	x(deleted,		0)			\
354 	x(whiteout,		1)			\
355 	x(error,		2)			\
356 	x(cookie,		3)			\
357 	x(hash_whiteout,	4)			\
358 	x(btree_ptr,		5)			\
359 	x(extent,		6)			\
360 	x(reservation,		7)			\
361 	x(inode,		8)			\
362 	x(inode_generation,	9)			\
363 	x(dirent,		10)			\
364 	x(xattr,		11)			\
365 	x(alloc,		12)			\
366 	x(quota,		13)			\
367 	x(stripe,		14)			\
368 	x(reflink_p,		15)			\
369 	x(reflink_v,		16)			\
370 	x(inline_data,		17)			\
371 	x(btree_ptr_v2,		18)			\
372 	x(indirect_inline_data,	19)			\
373 	x(alloc_v2,		20)			\
374 	x(subvolume,		21)			\
375 	x(snapshot,		22)			\
376 	x(inode_v2,		23)			\
377 	x(alloc_v3,		24)			\
378 	x(set,			25)			\
379 	x(lru,			26)			\
380 	x(alloc_v4,		27)			\
381 	x(backpointer,		28)			\
382 	x(inode_v3,		29)			\
383 	x(bucket_gens,		30)			\
384 	x(snapshot_tree,	31)			\
385 	x(logged_op_truncate,	32)			\
386 	x(logged_op_finsert,	33)
387 
388 enum bch_bkey_type {
389 #define x(name, nr) KEY_TYPE_##name	= nr,
390 	BCH_BKEY_TYPES()
391 #undef x
392 	KEY_TYPE_MAX,
393 };
394 
395 struct bch_deleted {
396 	struct bch_val		v;
397 };
398 
399 struct bch_whiteout {
400 	struct bch_val		v;
401 };
402 
403 struct bch_error {
404 	struct bch_val		v;
405 };
406 
407 struct bch_cookie {
408 	struct bch_val		v;
409 	__le64			cookie;
410 };
411 
412 struct bch_hash_whiteout {
413 	struct bch_val		v;
414 };
415 
416 struct bch_set {
417 	struct bch_val		v;
418 };
419 
420 /* Extents */
421 
422 /*
423  * In extent bkeys, the value is a list of pointers (bch_extent_ptr), optionally
424  * preceded by checksum/compression information (bch_extent_crc32 or
425  * bch_extent_crc64).
426  *
427  * One major determining factor in the format of extents is how we handle and
428  * represent extents that have been partially overwritten and thus trimmed:
429  *
430  * If an extent is not checksummed or compressed, when the extent is trimmed we
431  * don't have to remember the extent we originally allocated and wrote: we can
432  * merely adjust ptr->offset to point to the start of the data that is currently
433  * live. The size field in struct bkey records the current (live) size of the
434  * extent, and is also used to mean "size of region on disk that we point to" in
435  * this case.
436  *
437  * Thus an extent that is not checksummed or compressed will consist only of a
438  * list of bch_extent_ptrs, with none of the fields in
439  * bch_extent_crc32/bch_extent_crc64.
440  *
441  * When an extent is checksummed or compressed, it's not possible to read only
442  * the data that is currently live: we have to read the entire extent that was
443  * originally written, and then return only the part of the extent that is
444  * currently live.
445  *
446  * Thus, in addition to the current size of the extent in struct bkey, we need
447  * to store the size of the originally allocated space - this is the
448  * compressed_size and uncompressed_size fields in bch_extent_crc32/64. Also,
449  * when the extent is trimmed, instead of modifying the offset field of the
450  * pointer, we keep a second smaller offset field - "offset into the original
451  * extent of the currently live region".
452  *
453  * The other major determining factor is replication and data migration:
454  *
455  * Each pointer may have its own bch_extent_crc32/64. When doing a replicated
456  * write, we will initially write all the replicas in the same format, with the
457  * same checksum type and compression format - however, when copygc runs later (or
458  * tiering/cache promotion, anything that moves data), it is not in general
459  * going to rewrite all the pointers at once - one of the replicas may be in a
460  * bucket on one device that has very little fragmentation while another lives
461  * in a bucket that has become heavily fragmented, and thus is being rewritten
462  * sooner than the rest.
463  *
464  * Thus it will only move a subset of the pointers (or in the case of
465  * tiering/cache promotion perhaps add a single pointer without dropping any
466  * current pointers), and if the extent has been partially overwritten it must
467  * write only the currently live portion (or copygc would not be able to reduce
468  * fragmentation!) - which necessitates a different bch_extent_crc format for
469  * the new pointer.
470  *
471  * But in the interests of space efficiency, we don't want to store one
472  * bch_extent_crc for each pointer if we don't have to.
473  *
474  * Thus, a bch_extent consists of bch_extent_crc32s, bch_extent_crc64s, and
475  * bch_extent_ptrs appended arbitrarily one after the other. We determine the
476  * type of a given entry with a scheme similar to utf8 (except we're encoding a
477  * type, not a size), encoding the type in the position of the first set bit:
478  *
479  * bch_extent_crc32	- 0b1
480  * bch_extent_ptr	- 0b10
481  * bch_extent_crc64	- 0b100
482  *
483  * We do it this way because bch_extent_crc32 is _very_ constrained on bits (and
484  * bch_extent_crc64 is the least constrained).
485  *
486  * Then, each bch_extent_crc32/64 applies to the pointers that follow after it,
487  * until the next bch_extent_crc32/64.
488  *
489  * If there are no bch_extent_crcs preceding a bch_extent_ptr, then that pointer
490  * is neither checksummed nor compressed.
491  */
492 
493 /* 128 bits, sufficient for cryptographic MACs: */
494 struct bch_csum {
495 	__le64			lo;
496 	__le64			hi;
497 } __packed __aligned(8);
498 
499 #define BCH_EXTENT_ENTRY_TYPES()		\
500 	x(ptr,			0)		\
501 	x(crc32,		1)		\
502 	x(crc64,		2)		\
503 	x(crc128,		3)		\
504 	x(stripe_ptr,		4)		\
505 	x(rebalance,		5)
506 #define BCH_EXTENT_ENTRY_MAX	6
507 
508 enum bch_extent_entry_type {
509 #define x(f, n) BCH_EXTENT_ENTRY_##f = n,
510 	BCH_EXTENT_ENTRY_TYPES()
511 #undef x
512 };
513 
514 /* Compressed/uncompressed size are stored biased by 1: */
515 struct bch_extent_crc32 {
516 #if defined(__LITTLE_ENDIAN_BITFIELD)
517 	__u32			type:2,
518 				_compressed_size:7,
519 				_uncompressed_size:7,
520 				offset:7,
521 				_unused:1,
522 				csum_type:4,
523 				compression_type:4;
524 	__u32			csum;
525 #elif defined (__BIG_ENDIAN_BITFIELD)
526 	__u32			csum;
527 	__u32			compression_type:4,
528 				csum_type:4,
529 				_unused:1,
530 				offset:7,
531 				_uncompressed_size:7,
532 				_compressed_size:7,
533 				type:2;
534 #endif
535 } __packed __aligned(8);
536 
537 #define CRC32_SIZE_MAX		(1U << 7)
538 #define CRC32_NONCE_MAX		0
539 
540 struct bch_extent_crc64 {
541 #if defined(__LITTLE_ENDIAN_BITFIELD)
542 	__u64			type:3,
543 				_compressed_size:9,
544 				_uncompressed_size:9,
545 				offset:9,
546 				nonce:10,
547 				csum_type:4,
548 				compression_type:4,
549 				csum_hi:16;
550 #elif defined (__BIG_ENDIAN_BITFIELD)
551 	__u64			csum_hi:16,
552 				compression_type:4,
553 				csum_type:4,
554 				nonce:10,
555 				offset:9,
556 				_uncompressed_size:9,
557 				_compressed_size:9,
558 				type:3;
559 #endif
560 	__u64			csum_lo;
561 } __packed __aligned(8);
562 
563 #define CRC64_SIZE_MAX		(1U << 9)
564 #define CRC64_NONCE_MAX		((1U << 10) - 1)
565 
566 struct bch_extent_crc128 {
567 #if defined(__LITTLE_ENDIAN_BITFIELD)
568 	__u64			type:4,
569 				_compressed_size:13,
570 				_uncompressed_size:13,
571 				offset:13,
572 				nonce:13,
573 				csum_type:4,
574 				compression_type:4;
575 #elif defined (__BIG_ENDIAN_BITFIELD)
576 	__u64			compression_type:4,
577 				csum_type:4,
578 				nonce:13,
579 				offset:13,
580 				_uncompressed_size:13,
581 				_compressed_size:13,
582 				type:4;
583 #endif
584 	struct bch_csum		csum;
585 } __packed __aligned(8);
586 
587 #define CRC128_SIZE_MAX		(1U << 13)
588 #define CRC128_NONCE_MAX	((1U << 13) - 1)
589 
590 /*
591  * @reservation - pointer hasn't been written to, just reserved
592  */
593 struct bch_extent_ptr {
594 #if defined(__LITTLE_ENDIAN_BITFIELD)
595 	__u64			type:1,
596 				cached:1,
597 				unused:1,
598 				unwritten:1,
599 				offset:44, /* 8 petabytes */
600 				dev:8,
601 				gen:8;
602 #elif defined (__BIG_ENDIAN_BITFIELD)
603 	__u64			gen:8,
604 				dev:8,
605 				offset:44,
606 				unwritten:1,
607 				unused:1,
608 				cached:1,
609 				type:1;
610 #endif
611 } __packed __aligned(8);
612 
613 struct bch_extent_stripe_ptr {
614 #if defined(__LITTLE_ENDIAN_BITFIELD)
615 	__u64			type:5,
616 				block:8,
617 				redundancy:4,
618 				idx:47;
619 #elif defined (__BIG_ENDIAN_BITFIELD)
620 	__u64			idx:47,
621 				redundancy:4,
622 				block:8,
623 				type:5;
624 #endif
625 };
626 
627 struct bch_extent_rebalance {
628 #if defined(__LITTLE_ENDIAN_BITFIELD)
629 	__u64			type:6,
630 				unused:34,
631 				compression:8, /* enum bch_compression_opt */
632 				target:16;
633 #elif defined (__BIG_ENDIAN_BITFIELD)
634 	__u64			target:16,
635 				compression:8,
636 				unused:34,
637 				type:6;
638 #endif
639 };
640 
641 union bch_extent_entry {
642 #if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__ ||  __BITS_PER_LONG == 64
643 	unsigned long			type;
644 #elif __BITS_PER_LONG == 32
645 	struct {
646 		unsigned long		pad;
647 		unsigned long		type;
648 	};
649 #else
650 #error edit for your odd byteorder.
651 #endif
652 
653 #define x(f, n) struct bch_extent_##f	f;
654 	BCH_EXTENT_ENTRY_TYPES()
655 #undef x
656 };
657 
658 struct bch_btree_ptr {
659 	struct bch_val		v;
660 
661 	__u64			_data[0];
662 	struct bch_extent_ptr	start[];
663 } __packed __aligned(8);
664 
665 struct bch_btree_ptr_v2 {
666 	struct bch_val		v;
667 
668 	__u64			mem_ptr;
669 	__le64			seq;
670 	__le16			sectors_written;
671 	__le16			flags;
672 	struct bpos		min_key;
673 	__u64			_data[0];
674 	struct bch_extent_ptr	start[];
675 } __packed __aligned(8);
676 
677 LE16_BITMASK(BTREE_PTR_RANGE_UPDATED,	struct bch_btree_ptr_v2, flags, 0, 1);
678 
679 struct bch_extent {
680 	struct bch_val		v;
681 
682 	__u64			_data[0];
683 	union bch_extent_entry	start[];
684 } __packed __aligned(8);
685 
686 struct bch_reservation {
687 	struct bch_val		v;
688 
689 	__le32			generation;
690 	__u8			nr_replicas;
691 	__u8			pad[3];
692 } __packed __aligned(8);
693 
694 /* Maximum size (in u64s) a single pointer could be: */
695 #define BKEY_EXTENT_PTR_U64s_MAX\
696 	((sizeof(struct bch_extent_crc128) +			\
697 	  sizeof(struct bch_extent_ptr)) / sizeof(__u64))
698 
699 /* Maximum possible size of an entire extent value: */
700 #define BKEY_EXTENT_VAL_U64s_MAX				\
701 	(1 + BKEY_EXTENT_PTR_U64s_MAX * (BCH_REPLICAS_MAX + 1))
702 
703 /* * Maximum possible size of an entire extent, key + value: */
704 #define BKEY_EXTENT_U64s_MAX		(BKEY_U64s + BKEY_EXTENT_VAL_U64s_MAX)
705 
706 /* Btree pointers don't carry around checksums: */
707 #define BKEY_BTREE_PTR_VAL_U64s_MAX				\
708 	((sizeof(struct bch_btree_ptr_v2) +			\
709 	  sizeof(struct bch_extent_ptr) * BCH_REPLICAS_MAX) / sizeof(__u64))
710 #define BKEY_BTREE_PTR_U64s_MAX					\
711 	(BKEY_U64s + BKEY_BTREE_PTR_VAL_U64s_MAX)
712 
713 /* Inodes */
714 
715 #define BLOCKDEV_INODE_MAX	4096
716 
717 #define BCACHEFS_ROOT_INO	4096
718 
719 struct bch_inode {
720 	struct bch_val		v;
721 
722 	__le64			bi_hash_seed;
723 	__le32			bi_flags;
724 	__le16			bi_mode;
725 	__u8			fields[];
726 } __packed __aligned(8);
727 
728 struct bch_inode_v2 {
729 	struct bch_val		v;
730 
731 	__le64			bi_journal_seq;
732 	__le64			bi_hash_seed;
733 	__le64			bi_flags;
734 	__le16			bi_mode;
735 	__u8			fields[];
736 } __packed __aligned(8);
737 
738 struct bch_inode_v3 {
739 	struct bch_val		v;
740 
741 	__le64			bi_journal_seq;
742 	__le64			bi_hash_seed;
743 	__le64			bi_flags;
744 	__le64			bi_sectors;
745 	__le64			bi_size;
746 	__le64			bi_version;
747 	__u8			fields[];
748 } __packed __aligned(8);
749 
750 #define INODEv3_FIELDS_START_INITIAL	6
751 #define INODEv3_FIELDS_START_CUR	(offsetof(struct bch_inode_v3, fields) / sizeof(__u64))
752 
753 struct bch_inode_generation {
754 	struct bch_val		v;
755 
756 	__le32			bi_generation;
757 	__le32			pad;
758 } __packed __aligned(8);
759 
760 /*
761  * bi_subvol and bi_parent_subvol are only set for subvolume roots:
762  */
763 
764 #define BCH_INODE_FIELDS_v2()			\
765 	x(bi_atime,			96)	\
766 	x(bi_ctime,			96)	\
767 	x(bi_mtime,			96)	\
768 	x(bi_otime,			96)	\
769 	x(bi_size,			64)	\
770 	x(bi_sectors,			64)	\
771 	x(bi_uid,			32)	\
772 	x(bi_gid,			32)	\
773 	x(bi_nlink,			32)	\
774 	x(bi_generation,		32)	\
775 	x(bi_dev,			32)	\
776 	x(bi_data_checksum,		8)	\
777 	x(bi_compression,		8)	\
778 	x(bi_project,			32)	\
779 	x(bi_background_compression,	8)	\
780 	x(bi_data_replicas,		8)	\
781 	x(bi_promote_target,		16)	\
782 	x(bi_foreground_target,		16)	\
783 	x(bi_background_target,		16)	\
784 	x(bi_erasure_code,		16)	\
785 	x(bi_fields_set,		16)	\
786 	x(bi_dir,			64)	\
787 	x(bi_dir_offset,		64)	\
788 	x(bi_subvol,			32)	\
789 	x(bi_parent_subvol,		32)
790 
791 #define BCH_INODE_FIELDS_v3()			\
792 	x(bi_atime,			96)	\
793 	x(bi_ctime,			96)	\
794 	x(bi_mtime,			96)	\
795 	x(bi_otime,			96)	\
796 	x(bi_uid,			32)	\
797 	x(bi_gid,			32)	\
798 	x(bi_nlink,			32)	\
799 	x(bi_generation,		32)	\
800 	x(bi_dev,			32)	\
801 	x(bi_data_checksum,		8)	\
802 	x(bi_compression,		8)	\
803 	x(bi_project,			32)	\
804 	x(bi_background_compression,	8)	\
805 	x(bi_data_replicas,		8)	\
806 	x(bi_promote_target,		16)	\
807 	x(bi_foreground_target,		16)	\
808 	x(bi_background_target,		16)	\
809 	x(bi_erasure_code,		16)	\
810 	x(bi_fields_set,		16)	\
811 	x(bi_dir,			64)	\
812 	x(bi_dir_offset,		64)	\
813 	x(bi_subvol,			32)	\
814 	x(bi_parent_subvol,		32)	\
815 	x(bi_nocow,			8)
816 
817 /* subset of BCH_INODE_FIELDS */
818 #define BCH_INODE_OPTS()			\
819 	x(data_checksum,		8)	\
820 	x(compression,			8)	\
821 	x(project,			32)	\
822 	x(background_compression,	8)	\
823 	x(data_replicas,		8)	\
824 	x(promote_target,		16)	\
825 	x(foreground_target,		16)	\
826 	x(background_target,		16)	\
827 	x(erasure_code,			16)	\
828 	x(nocow,			8)
829 
830 enum inode_opt_id {
831 #define x(name, ...)				\
832 	Inode_opt_##name,
833 	BCH_INODE_OPTS()
834 #undef  x
835 	Inode_opt_nr,
836 };
837 
838 #define BCH_INODE_FLAGS()			\
839 	x(sync,				0)	\
840 	x(immutable,			1)	\
841 	x(append,			2)	\
842 	x(nodump,			3)	\
843 	x(noatime,			4)	\
844 	x(i_size_dirty,			5)	\
845 	x(i_sectors_dirty,		6)	\
846 	x(unlinked,			7)	\
847 	x(backptr_untrusted,		8)
848 
849 /* bits 20+ reserved for packed fields below: */
850 
851 enum bch_inode_flags {
852 #define x(t, n)	BCH_INODE_##t = 1U << n,
853 	BCH_INODE_FLAGS()
854 #undef x
855 };
856 
857 enum __bch_inode_flags {
858 #define x(t, n)	__BCH_INODE_##t = n,
859 	BCH_INODE_FLAGS()
860 #undef x
861 };
862 
863 LE32_BITMASK(INODE_STR_HASH,	struct bch_inode, bi_flags, 20, 24);
864 LE32_BITMASK(INODE_NR_FIELDS,	struct bch_inode, bi_flags, 24, 31);
865 LE32_BITMASK(INODE_NEW_VARINT,	struct bch_inode, bi_flags, 31, 32);
866 
867 LE64_BITMASK(INODEv2_STR_HASH,	struct bch_inode_v2, bi_flags, 20, 24);
868 LE64_BITMASK(INODEv2_NR_FIELDS,	struct bch_inode_v2, bi_flags, 24, 31);
869 
870 LE64_BITMASK(INODEv3_STR_HASH,	struct bch_inode_v3, bi_flags, 20, 24);
871 LE64_BITMASK(INODEv3_NR_FIELDS,	struct bch_inode_v3, bi_flags, 24, 31);
872 
873 LE64_BITMASK(INODEv3_FIELDS_START,
874 				struct bch_inode_v3, bi_flags, 31, 36);
875 LE64_BITMASK(INODEv3_MODE,	struct bch_inode_v3, bi_flags, 36, 52);
876 
877 /* Dirents */
878 
879 /*
880  * Dirents (and xattrs) have to implement string lookups; since our b-tree
881  * doesn't support arbitrary length strings for the key, we instead index by a
882  * 64 bit hash (currently truncated sha1) of the string, stored in the offset
883  * field of the key - using linear probing to resolve hash collisions. This also
884  * provides us with the readdir cookie posix requires.
885  *
886  * Linear probing requires us to use whiteouts for deletions, in the event of a
887  * collision:
888  */
889 
890 struct bch_dirent {
891 	struct bch_val		v;
892 
893 	/* Target inode number: */
894 	union {
895 	__le64			d_inum;
896 	struct {		/* DT_SUBVOL */
897 	__le32			d_child_subvol;
898 	__le32			d_parent_subvol;
899 	};
900 	};
901 
902 	/*
903 	 * Copy of mode bits 12-15 from the target inode - so userspace can get
904 	 * the filetype without having to do a stat()
905 	 */
906 	__u8			d_type;
907 
908 	__u8			d_name[];
909 } __packed __aligned(8);
910 
911 #define DT_SUBVOL	16
912 #define BCH_DT_MAX	17
913 
914 #define BCH_NAME_MAX	512
915 
916 /* Xattrs */
917 
918 #define KEY_TYPE_XATTR_INDEX_USER			0
919 #define KEY_TYPE_XATTR_INDEX_POSIX_ACL_ACCESS	1
920 #define KEY_TYPE_XATTR_INDEX_POSIX_ACL_DEFAULT	2
921 #define KEY_TYPE_XATTR_INDEX_TRUSTED			3
922 #define KEY_TYPE_XATTR_INDEX_SECURITY	        4
923 
924 struct bch_xattr {
925 	struct bch_val		v;
926 	__u8			x_type;
927 	__u8			x_name_len;
928 	__le16			x_val_len;
929 	__u8			x_name[];
930 } __packed __aligned(8);
931 
932 /* Bucket/allocation information: */
933 
934 struct bch_alloc {
935 	struct bch_val		v;
936 	__u8			fields;
937 	__u8			gen;
938 	__u8			data[];
939 } __packed __aligned(8);
940 
941 #define BCH_ALLOC_FIELDS_V1()			\
942 	x(read_time,		16)		\
943 	x(write_time,		16)		\
944 	x(data_type,		8)		\
945 	x(dirty_sectors,	16)		\
946 	x(cached_sectors,	16)		\
947 	x(oldest_gen,		8)		\
948 	x(stripe,		32)		\
949 	x(stripe_redundancy,	8)
950 
951 enum {
952 #define x(name, _bits) BCH_ALLOC_FIELD_V1_##name,
953 	BCH_ALLOC_FIELDS_V1()
954 #undef x
955 };
956 
957 struct bch_alloc_v2 {
958 	struct bch_val		v;
959 	__u8			nr_fields;
960 	__u8			gen;
961 	__u8			oldest_gen;
962 	__u8			data_type;
963 	__u8			data[];
964 } __packed __aligned(8);
965 
966 #define BCH_ALLOC_FIELDS_V2()			\
967 	x(read_time,		64)		\
968 	x(write_time,		64)		\
969 	x(dirty_sectors,	32)		\
970 	x(cached_sectors,	32)		\
971 	x(stripe,		32)		\
972 	x(stripe_redundancy,	8)
973 
974 struct bch_alloc_v3 {
975 	struct bch_val		v;
976 	__le64			journal_seq;
977 	__le32			flags;
978 	__u8			nr_fields;
979 	__u8			gen;
980 	__u8			oldest_gen;
981 	__u8			data_type;
982 	__u8			data[];
983 } __packed __aligned(8);
984 
985 LE32_BITMASK(BCH_ALLOC_V3_NEED_DISCARD,struct bch_alloc_v3, flags,  0,  1)
986 LE32_BITMASK(BCH_ALLOC_V3_NEED_INC_GEN,struct bch_alloc_v3, flags,  1,  2)
987 
988 struct bch_alloc_v4 {
989 	struct bch_val		v;
990 	__u64			journal_seq;
991 	__u32			flags;
992 	__u8			gen;
993 	__u8			oldest_gen;
994 	__u8			data_type;
995 	__u8			stripe_redundancy;
996 	__u32			dirty_sectors;
997 	__u32			cached_sectors;
998 	__u64			io_time[2];
999 	__u32			stripe;
1000 	__u32			nr_external_backpointers;
1001 	__u64			fragmentation_lru;
1002 } __packed __aligned(8);
1003 
1004 #define BCH_ALLOC_V4_U64s_V0	6
1005 #define BCH_ALLOC_V4_U64s	(sizeof(struct bch_alloc_v4) / sizeof(__u64))
1006 
1007 BITMASK(BCH_ALLOC_V4_NEED_DISCARD,	struct bch_alloc_v4, flags,  0,  1)
1008 BITMASK(BCH_ALLOC_V4_NEED_INC_GEN,	struct bch_alloc_v4, flags,  1,  2)
1009 BITMASK(BCH_ALLOC_V4_BACKPOINTERS_START,struct bch_alloc_v4, flags,  2,  8)
1010 BITMASK(BCH_ALLOC_V4_NR_BACKPOINTERS,	struct bch_alloc_v4, flags,  8,  14)
1011 
1012 #define BCH_ALLOC_V4_NR_BACKPOINTERS_MAX	40
1013 
1014 struct bch_backpointer {
1015 	struct bch_val		v;
1016 	__u8			btree_id;
1017 	__u8			level;
1018 	__u8			data_type;
1019 	__u64			bucket_offset:40;
1020 	__u32			bucket_len;
1021 	struct bpos		pos;
1022 } __packed __aligned(8);
1023 
1024 #define KEY_TYPE_BUCKET_GENS_BITS	8
1025 #define KEY_TYPE_BUCKET_GENS_NR		(1U << KEY_TYPE_BUCKET_GENS_BITS)
1026 #define KEY_TYPE_BUCKET_GENS_MASK	(KEY_TYPE_BUCKET_GENS_NR - 1)
1027 
1028 struct bch_bucket_gens {
1029 	struct bch_val		v;
1030 	u8			gens[KEY_TYPE_BUCKET_GENS_NR];
1031 } __packed __aligned(8);
1032 
1033 /* Quotas: */
1034 
1035 enum quota_types {
1036 	QTYP_USR		= 0,
1037 	QTYP_GRP		= 1,
1038 	QTYP_PRJ		= 2,
1039 	QTYP_NR			= 3,
1040 };
1041 
1042 enum quota_counters {
1043 	Q_SPC			= 0,
1044 	Q_INO			= 1,
1045 	Q_COUNTERS		= 2,
1046 };
1047 
1048 struct bch_quota_counter {
1049 	__le64			hardlimit;
1050 	__le64			softlimit;
1051 };
1052 
1053 struct bch_quota {
1054 	struct bch_val		v;
1055 	struct bch_quota_counter c[Q_COUNTERS];
1056 } __packed __aligned(8);
1057 
1058 /* Erasure coding */
1059 
1060 struct bch_stripe {
1061 	struct bch_val		v;
1062 	__le16			sectors;
1063 	__u8			algorithm;
1064 	__u8			nr_blocks;
1065 	__u8			nr_redundant;
1066 
1067 	__u8			csum_granularity_bits;
1068 	__u8			csum_type;
1069 	__u8			pad;
1070 
1071 	struct bch_extent_ptr	ptrs[];
1072 } __packed __aligned(8);
1073 
1074 /* Reflink: */
1075 
1076 struct bch_reflink_p {
1077 	struct bch_val		v;
1078 	__le64			idx;
1079 	/*
1080 	 * A reflink pointer might point to an indirect extent which is then
1081 	 * later split (by copygc or rebalance). If we only pointed to part of
1082 	 * the original indirect extent, and then one of the fragments is
1083 	 * outside the range we point to, we'd leak a refcount: so when creating
1084 	 * reflink pointers, we need to store pad values to remember the full
1085 	 * range we were taking a reference on.
1086 	 */
1087 	__le32			front_pad;
1088 	__le32			back_pad;
1089 } __packed __aligned(8);
1090 
1091 struct bch_reflink_v {
1092 	struct bch_val		v;
1093 	__le64			refcount;
1094 	union bch_extent_entry	start[0];
1095 	__u64			_data[];
1096 } __packed __aligned(8);
1097 
1098 struct bch_indirect_inline_data {
1099 	struct bch_val		v;
1100 	__le64			refcount;
1101 	u8			data[];
1102 };
1103 
1104 /* Inline data */
1105 
1106 struct bch_inline_data {
1107 	struct bch_val		v;
1108 	u8			data[];
1109 };
1110 
1111 /* Subvolumes: */
1112 
1113 #define SUBVOL_POS_MIN		POS(0, 1)
1114 #define SUBVOL_POS_MAX		POS(0, S32_MAX)
1115 #define BCACHEFS_ROOT_SUBVOL	1
1116 
1117 struct bch_subvolume {
1118 	struct bch_val		v;
1119 	__le32			flags;
1120 	__le32			snapshot;
1121 	__le64			inode;
1122 	/*
1123 	 * Snapshot subvolumes form a tree, separate from the snapshot nodes
1124 	 * tree - if this subvolume is a snapshot, this is the ID of the
1125 	 * subvolume it was created from:
1126 	 */
1127 	__le32			parent;
1128 	__le32			pad;
1129 	bch_le128		otime;
1130 };
1131 
1132 LE32_BITMASK(BCH_SUBVOLUME_RO,		struct bch_subvolume, flags,  0,  1)
1133 /*
1134  * We need to know whether a subvolume is a snapshot so we can know whether we
1135  * can delete it (or whether it should just be rm -rf'd)
1136  */
1137 LE32_BITMASK(BCH_SUBVOLUME_SNAP,	struct bch_subvolume, flags,  1,  2)
1138 LE32_BITMASK(BCH_SUBVOLUME_UNLINKED,	struct bch_subvolume, flags,  2,  3)
1139 
1140 /* Snapshots */
1141 
1142 struct bch_snapshot {
1143 	struct bch_val		v;
1144 	__le32			flags;
1145 	__le32			parent;
1146 	__le32			children[2];
1147 	__le32			subvol;
1148 	/* corresponds to a bch_snapshot_tree in BTREE_ID_snapshot_trees */
1149 	__le32			tree;
1150 	__le32			depth;
1151 	__le32			skip[3];
1152 };
1153 
1154 LE32_BITMASK(BCH_SNAPSHOT_DELETED,	struct bch_snapshot, flags,  0,  1)
1155 
1156 /* True if a subvolume points to this snapshot node: */
1157 LE32_BITMASK(BCH_SNAPSHOT_SUBVOL,	struct bch_snapshot, flags,  1,  2)
1158 
1159 /*
1160  * Snapshot trees:
1161  *
1162  * The snapshot_trees btree gives us persistent indentifier for each tree of
1163  * bch_snapshot nodes, and allow us to record and easily find the root/master
1164  * subvolume that other snapshots were created from:
1165  */
1166 struct bch_snapshot_tree {
1167 	struct bch_val		v;
1168 	__le32			master_subvol;
1169 	__le32			root_snapshot;
1170 };
1171 
1172 /* LRU btree: */
1173 
1174 struct bch_lru {
1175 	struct bch_val		v;
1176 	__le64			idx;
1177 } __packed __aligned(8);
1178 
1179 #define LRU_ID_STRIPES		(1U << 16)
1180 
1181 /* Logged operations btree: */
1182 
1183 struct bch_logged_op_truncate {
1184 	struct bch_val		v;
1185 	__le32			subvol;
1186 	__le32			pad;
1187 	__le64			inum;
1188 	__le64			new_i_size;
1189 };
1190 
1191 enum logged_op_finsert_state {
1192 	LOGGED_OP_FINSERT_start,
1193 	LOGGED_OP_FINSERT_shift_extents,
1194 	LOGGED_OP_FINSERT_finish,
1195 };
1196 
1197 struct bch_logged_op_finsert {
1198 	struct bch_val		v;
1199 	__u8			state;
1200 	__u8			pad[3];
1201 	__le32			subvol;
1202 	__le64			inum;
1203 	__le64			dst_offset;
1204 	__le64			src_offset;
1205 	__le64			pos;
1206 };
1207 
1208 /* Optional/variable size superblock sections: */
1209 
1210 struct bch_sb_field {
1211 	__u64			_data[0];
1212 	__le32			u64s;
1213 	__le32			type;
1214 };
1215 
1216 #define BCH_SB_FIELDS()				\
1217 	x(journal,			0)	\
1218 	x(members_v1,			1)	\
1219 	x(crypt,			2)	\
1220 	x(replicas_v0,			3)	\
1221 	x(quota,			4)	\
1222 	x(disk_groups,			5)	\
1223 	x(clean,			6)	\
1224 	x(replicas,			7)	\
1225 	x(journal_seq_blacklist,	8)	\
1226 	x(journal_v2,			9)	\
1227 	x(counters,			10)	\
1228 	x(members_v2,			11)	\
1229 	x(errors,			12)	\
1230 	x(ext,				13)	\
1231 	x(downgrade,			14)
1232 
1233 enum bch_sb_field_type {
1234 #define x(f, nr)	BCH_SB_FIELD_##f = nr,
1235 	BCH_SB_FIELDS()
1236 #undef x
1237 	BCH_SB_FIELD_NR
1238 };
1239 
1240 /*
1241  * Most superblock fields are replicated in all device's superblocks - a few are
1242  * not:
1243  */
1244 #define BCH_SINGLE_DEVICE_SB_FIELDS		\
1245 	((1U << BCH_SB_FIELD_journal)|		\
1246 	 (1U << BCH_SB_FIELD_journal_v2))
1247 
1248 /* BCH_SB_FIELD_journal: */
1249 
1250 struct bch_sb_field_journal {
1251 	struct bch_sb_field	field;
1252 	__le64			buckets[];
1253 };
1254 
1255 struct bch_sb_field_journal_v2 {
1256 	struct bch_sb_field	field;
1257 
1258 	struct bch_sb_field_journal_v2_entry {
1259 		__le64		start;
1260 		__le64		nr;
1261 	}			d[];
1262 };
1263 
1264 /* BCH_SB_FIELD_members_v1: */
1265 
1266 #define BCH_MIN_NR_NBUCKETS	(1 << 6)
1267 
1268 #define BCH_IOPS_MEASUREMENTS()			\
1269 	x(seqread,	0)			\
1270 	x(seqwrite,	1)			\
1271 	x(randread,	2)			\
1272 	x(randwrite,	3)
1273 
1274 enum bch_iops_measurement {
1275 #define x(t, n) BCH_IOPS_##t = n,
1276 	BCH_IOPS_MEASUREMENTS()
1277 #undef x
1278 	BCH_IOPS_NR
1279 };
1280 
1281 #define BCH_MEMBER_ERROR_TYPES()		\
1282 	x(read,		0)			\
1283 	x(write,	1)			\
1284 	x(checksum,	2)
1285 
1286 enum bch_member_error_type {
1287 #define x(t, n) BCH_MEMBER_ERROR_##t = n,
1288 	BCH_MEMBER_ERROR_TYPES()
1289 #undef x
1290 	BCH_MEMBER_ERROR_NR
1291 };
1292 
1293 struct bch_member {
1294 	__uuid_t		uuid;
1295 	__le64			nbuckets;	/* device size */
1296 	__le16			first_bucket;   /* index of first bucket used */
1297 	__le16			bucket_size;	/* sectors */
1298 	__le32			pad;
1299 	__le64			last_mount;	/* time_t */
1300 
1301 	__le64			flags;
1302 	__le32			iops[4];
1303 	__le64			errors[BCH_MEMBER_ERROR_NR];
1304 	__le64			errors_at_reset[BCH_MEMBER_ERROR_NR];
1305 	__le64			errors_reset_time;
1306 	__le64			seq;
1307 };
1308 
1309 #define BCH_MEMBER_V1_BYTES	56
1310 
1311 LE64_BITMASK(BCH_MEMBER_STATE,		struct bch_member, flags,  0,  4)
1312 /* 4-14 unused, was TIER, HAS_(META)DATA, REPLACEMENT */
1313 LE64_BITMASK(BCH_MEMBER_DISCARD,	struct bch_member, flags, 14, 15)
1314 LE64_BITMASK(BCH_MEMBER_DATA_ALLOWED,	struct bch_member, flags, 15, 20)
1315 LE64_BITMASK(BCH_MEMBER_GROUP,		struct bch_member, flags, 20, 28)
1316 LE64_BITMASK(BCH_MEMBER_DURABILITY,	struct bch_member, flags, 28, 30)
1317 LE64_BITMASK(BCH_MEMBER_FREESPACE_INITIALIZED,
1318 					struct bch_member, flags, 30, 31)
1319 
1320 #if 0
1321 LE64_BITMASK(BCH_MEMBER_NR_READ_ERRORS,	struct bch_member, flags[1], 0,  20);
1322 LE64_BITMASK(BCH_MEMBER_NR_WRITE_ERRORS,struct bch_member, flags[1], 20, 40);
1323 #endif
1324 
1325 #define BCH_MEMBER_STATES()			\
1326 	x(rw,		0)			\
1327 	x(ro,		1)			\
1328 	x(failed,	2)			\
1329 	x(spare,	3)
1330 
1331 enum bch_member_state {
1332 #define x(t, n) BCH_MEMBER_STATE_##t = n,
1333 	BCH_MEMBER_STATES()
1334 #undef x
1335 	BCH_MEMBER_STATE_NR
1336 };
1337 
1338 struct bch_sb_field_members_v1 {
1339 	struct bch_sb_field	field;
1340 	struct bch_member	_members[]; //Members are now variable size
1341 };
1342 
1343 struct bch_sb_field_members_v2 {
1344 	struct bch_sb_field	field;
1345 	__le16			member_bytes; //size of single member entry
1346 	u8			pad[6];
1347 	struct bch_member	_members[];
1348 };
1349 
1350 /* BCH_SB_FIELD_crypt: */
1351 
1352 struct nonce {
1353 	__le32			d[4];
1354 };
1355 
1356 struct bch_key {
1357 	__le64			key[4];
1358 };
1359 
1360 #define BCH_KEY_MAGIC					\
1361 	(((__u64) 'b' <<  0)|((__u64) 'c' <<  8)|		\
1362 	 ((__u64) 'h' << 16)|((__u64) '*' << 24)|		\
1363 	 ((__u64) '*' << 32)|((__u64) 'k' << 40)|		\
1364 	 ((__u64) 'e' << 48)|((__u64) 'y' << 56))
1365 
1366 struct bch_encrypted_key {
1367 	__le64			magic;
1368 	struct bch_key		key;
1369 };
1370 
1371 /*
1372  * If this field is present in the superblock, it stores an encryption key which
1373  * is used encrypt all other data/metadata. The key will normally be encrypted
1374  * with the key userspace provides, but if encryption has been turned off we'll
1375  * just store the master key unencrypted in the superblock so we can access the
1376  * previously encrypted data.
1377  */
1378 struct bch_sb_field_crypt {
1379 	struct bch_sb_field	field;
1380 
1381 	__le64			flags;
1382 	__le64			kdf_flags;
1383 	struct bch_encrypted_key key;
1384 };
1385 
1386 LE64_BITMASK(BCH_CRYPT_KDF_TYPE,	struct bch_sb_field_crypt, flags, 0, 4);
1387 
1388 enum bch_kdf_types {
1389 	BCH_KDF_SCRYPT		= 0,
1390 	BCH_KDF_NR		= 1,
1391 };
1392 
1393 /* stored as base 2 log of scrypt params: */
1394 LE64_BITMASK(BCH_KDF_SCRYPT_N,	struct bch_sb_field_crypt, kdf_flags,  0, 16);
1395 LE64_BITMASK(BCH_KDF_SCRYPT_R,	struct bch_sb_field_crypt, kdf_flags, 16, 32);
1396 LE64_BITMASK(BCH_KDF_SCRYPT_P,	struct bch_sb_field_crypt, kdf_flags, 32, 48);
1397 
1398 /* BCH_SB_FIELD_replicas: */
1399 
1400 #define BCH_DATA_TYPES()		\
1401 	x(free,		0)		\
1402 	x(sb,		1)		\
1403 	x(journal,	2)		\
1404 	x(btree,	3)		\
1405 	x(user,		4)		\
1406 	x(cached,	5)		\
1407 	x(parity,	6)		\
1408 	x(stripe,	7)		\
1409 	x(need_gc_gens,	8)		\
1410 	x(need_discard,	9)
1411 
1412 enum bch_data_type {
1413 #define x(t, n) BCH_DATA_##t,
1414 	BCH_DATA_TYPES()
1415 #undef x
1416 	BCH_DATA_NR
1417 };
1418 
1419 static inline bool data_type_is_empty(enum bch_data_type type)
1420 {
1421 	switch (type) {
1422 	case BCH_DATA_free:
1423 	case BCH_DATA_need_gc_gens:
1424 	case BCH_DATA_need_discard:
1425 		return true;
1426 	default:
1427 		return false;
1428 	}
1429 }
1430 
1431 static inline bool data_type_is_hidden(enum bch_data_type type)
1432 {
1433 	switch (type) {
1434 	case BCH_DATA_sb:
1435 	case BCH_DATA_journal:
1436 		return true;
1437 	default:
1438 		return false;
1439 	}
1440 }
1441 
1442 struct bch_replicas_entry_v0 {
1443 	__u8			data_type;
1444 	__u8			nr_devs;
1445 	__u8			devs[];
1446 } __packed;
1447 
1448 struct bch_sb_field_replicas_v0 {
1449 	struct bch_sb_field	field;
1450 	struct bch_replicas_entry_v0 entries[];
1451 } __packed __aligned(8);
1452 
1453 struct bch_replicas_entry_v1 {
1454 	__u8			data_type;
1455 	__u8			nr_devs;
1456 	__u8			nr_required;
1457 	__u8			devs[];
1458 } __packed;
1459 
1460 #define replicas_entry_bytes(_i)					\
1461 	(offsetof(typeof(*(_i)), devs) + (_i)->nr_devs)
1462 
1463 struct bch_sb_field_replicas {
1464 	struct bch_sb_field	field;
1465 	struct bch_replicas_entry_v1 entries[];
1466 } __packed __aligned(8);
1467 
1468 /* BCH_SB_FIELD_quota: */
1469 
1470 struct bch_sb_quota_counter {
1471 	__le32				timelimit;
1472 	__le32				warnlimit;
1473 };
1474 
1475 struct bch_sb_quota_type {
1476 	__le64				flags;
1477 	struct bch_sb_quota_counter	c[Q_COUNTERS];
1478 };
1479 
1480 struct bch_sb_field_quota {
1481 	struct bch_sb_field		field;
1482 	struct bch_sb_quota_type	q[QTYP_NR];
1483 } __packed __aligned(8);
1484 
1485 /* BCH_SB_FIELD_disk_groups: */
1486 
1487 #define BCH_SB_LABEL_SIZE		32
1488 
1489 struct bch_disk_group {
1490 	__u8			label[BCH_SB_LABEL_SIZE];
1491 	__le64			flags[2];
1492 } __packed __aligned(8);
1493 
1494 LE64_BITMASK(BCH_GROUP_DELETED,		struct bch_disk_group, flags[0], 0,  1)
1495 LE64_BITMASK(BCH_GROUP_DATA_ALLOWED,	struct bch_disk_group, flags[0], 1,  6)
1496 LE64_BITMASK(BCH_GROUP_PARENT,		struct bch_disk_group, flags[0], 6, 24)
1497 
1498 struct bch_sb_field_disk_groups {
1499 	struct bch_sb_field	field;
1500 	struct bch_disk_group	entries[];
1501 } __packed __aligned(8);
1502 
1503 /* BCH_SB_FIELD_counters */
1504 
1505 #define BCH_PERSISTENT_COUNTERS()				\
1506 	x(io_read,					0)	\
1507 	x(io_write,					1)	\
1508 	x(io_move,					2)	\
1509 	x(bucket_invalidate,				3)	\
1510 	x(bucket_discard,				4)	\
1511 	x(bucket_alloc,					5)	\
1512 	x(bucket_alloc_fail,				6)	\
1513 	x(btree_cache_scan,				7)	\
1514 	x(btree_cache_reap,				8)	\
1515 	x(btree_cache_cannibalize,			9)	\
1516 	x(btree_cache_cannibalize_lock,			10)	\
1517 	x(btree_cache_cannibalize_lock_fail,		11)	\
1518 	x(btree_cache_cannibalize_unlock,		12)	\
1519 	x(btree_node_write,				13)	\
1520 	x(btree_node_read,				14)	\
1521 	x(btree_node_compact,				15)	\
1522 	x(btree_node_merge,				16)	\
1523 	x(btree_node_split,				17)	\
1524 	x(btree_node_rewrite,				18)	\
1525 	x(btree_node_alloc,				19)	\
1526 	x(btree_node_free,				20)	\
1527 	x(btree_node_set_root,				21)	\
1528 	x(btree_path_relock_fail,			22)	\
1529 	x(btree_path_upgrade_fail,			23)	\
1530 	x(btree_reserve_get_fail,			24)	\
1531 	x(journal_entry_full,				25)	\
1532 	x(journal_full,					26)	\
1533 	x(journal_reclaim_finish,			27)	\
1534 	x(journal_reclaim_start,			28)	\
1535 	x(journal_write,				29)	\
1536 	x(read_promote,					30)	\
1537 	x(read_bounce,					31)	\
1538 	x(read_split,					33)	\
1539 	x(read_retry,					32)	\
1540 	x(read_reuse_race,				34)	\
1541 	x(move_extent_read,				35)	\
1542 	x(move_extent_write,				36)	\
1543 	x(move_extent_finish,				37)	\
1544 	x(move_extent_fail,				38)	\
1545 	x(move_extent_start_fail,			39)	\
1546 	x(copygc,					40)	\
1547 	x(copygc_wait,					41)	\
1548 	x(gc_gens_end,					42)	\
1549 	x(gc_gens_start,				43)	\
1550 	x(trans_blocked_journal_reclaim,		44)	\
1551 	x(trans_restart_btree_node_reused,		45)	\
1552 	x(trans_restart_btree_node_split,		46)	\
1553 	x(trans_restart_fault_inject,			47)	\
1554 	x(trans_restart_iter_upgrade,			48)	\
1555 	x(trans_restart_journal_preres_get,		49)	\
1556 	x(trans_restart_journal_reclaim,		50)	\
1557 	x(trans_restart_journal_res_get,		51)	\
1558 	x(trans_restart_key_cache_key_realloced,	52)	\
1559 	x(trans_restart_key_cache_raced,		53)	\
1560 	x(trans_restart_mark_replicas,			54)	\
1561 	x(trans_restart_mem_realloced,			55)	\
1562 	x(trans_restart_memory_allocation_failure,	56)	\
1563 	x(trans_restart_relock,				57)	\
1564 	x(trans_restart_relock_after_fill,		58)	\
1565 	x(trans_restart_relock_key_cache_fill,		59)	\
1566 	x(trans_restart_relock_next_node,		60)	\
1567 	x(trans_restart_relock_parent_for_fill,		61)	\
1568 	x(trans_restart_relock_path,			62)	\
1569 	x(trans_restart_relock_path_intent,		63)	\
1570 	x(trans_restart_too_many_iters,			64)	\
1571 	x(trans_restart_traverse,			65)	\
1572 	x(trans_restart_upgrade,			66)	\
1573 	x(trans_restart_would_deadlock,			67)	\
1574 	x(trans_restart_would_deadlock_write,		68)	\
1575 	x(trans_restart_injected,			69)	\
1576 	x(trans_restart_key_cache_upgrade,		70)	\
1577 	x(trans_traverse_all,				71)	\
1578 	x(transaction_commit,				72)	\
1579 	x(write_super,					73)	\
1580 	x(trans_restart_would_deadlock_recursion_limit,	74)	\
1581 	x(trans_restart_write_buffer_flush,		75)	\
1582 	x(trans_restart_split_race,			76)	\
1583 	x(write_buffer_flush_slowpath,			77)	\
1584 	x(write_buffer_flush_sync,			78)
1585 
1586 enum bch_persistent_counters {
1587 #define x(t, n, ...) BCH_COUNTER_##t,
1588 	BCH_PERSISTENT_COUNTERS()
1589 #undef x
1590 	BCH_COUNTER_NR
1591 };
1592 
1593 struct bch_sb_field_counters {
1594 	struct bch_sb_field	field;
1595 	__le64			d[];
1596 };
1597 
1598 /*
1599  * On clean shutdown, store btree roots and current journal sequence number in
1600  * the superblock:
1601  */
1602 struct jset_entry {
1603 	__le16			u64s;
1604 	__u8			btree_id;
1605 	__u8			level;
1606 	__u8			type; /* designates what this jset holds */
1607 	__u8			pad[3];
1608 
1609 	struct bkey_i		start[0];
1610 	__u64			_data[];
1611 };
1612 
1613 struct bch_sb_field_clean {
1614 	struct bch_sb_field	field;
1615 
1616 	__le32			flags;
1617 	__le16			_read_clock; /* no longer used */
1618 	__le16			_write_clock;
1619 	__le64			journal_seq;
1620 
1621 	struct jset_entry	start[0];
1622 	__u64			_data[];
1623 };
1624 
1625 struct journal_seq_blacklist_entry {
1626 	__le64			start;
1627 	__le64			end;
1628 };
1629 
1630 struct bch_sb_field_journal_seq_blacklist {
1631 	struct bch_sb_field	field;
1632 	struct journal_seq_blacklist_entry start[];
1633 };
1634 
1635 struct bch_sb_field_errors {
1636 	struct bch_sb_field	field;
1637 	struct bch_sb_field_error_entry {
1638 		__le64		v;
1639 		__le64		last_error_time;
1640 	}			entries[];
1641 };
1642 
1643 LE64_BITMASK(BCH_SB_ERROR_ENTRY_ID,	struct bch_sb_field_error_entry, v,  0, 16);
1644 LE64_BITMASK(BCH_SB_ERROR_ENTRY_NR,	struct bch_sb_field_error_entry, v, 16, 64);
1645 
1646 struct bch_sb_field_ext {
1647 	struct bch_sb_field	field;
1648 	__le64			recovery_passes_required[2];
1649 	__le64			errors_silent[8];
1650 };
1651 
1652 struct bch_sb_field_downgrade_entry {
1653 	__le16			version;
1654 	__le64			recovery_passes[2];
1655 	__le16			nr_errors;
1656 	__le16			errors[] __counted_by(nr_errors);
1657 } __packed __aligned(2);
1658 
1659 struct bch_sb_field_downgrade {
1660 	struct bch_sb_field	field;
1661 	struct bch_sb_field_downgrade_entry entries[];
1662 };
1663 
1664 /* Superblock: */
1665 
1666 /*
1667  * New versioning scheme:
1668  * One common version number for all on disk data structures - superblock, btree
1669  * nodes, journal entries
1670  */
1671 #define BCH_VERSION_MAJOR(_v)		((__u16) ((_v) >> 10))
1672 #define BCH_VERSION_MINOR(_v)		((__u16) ((_v) & ~(~0U << 10)))
1673 #define BCH_VERSION(_major, _minor)	(((_major) << 10)|(_minor) << 0)
1674 
1675 /*
1676  * field 1:		version name
1677  * field 2:		BCH_VERSION(major, minor)
1678  * field 3:		recovery passess required on upgrade
1679  */
1680 #define BCH_METADATA_VERSIONS()						\
1681 	x(bkey_renumber,		BCH_VERSION(0, 10))		\
1682 	x(inode_btree_change,		BCH_VERSION(0, 11))		\
1683 	x(snapshot,			BCH_VERSION(0, 12))		\
1684 	x(inode_backpointers,		BCH_VERSION(0, 13))		\
1685 	x(btree_ptr_sectors_written,	BCH_VERSION(0, 14))		\
1686 	x(snapshot_2,			BCH_VERSION(0, 15))		\
1687 	x(reflink_p_fix,		BCH_VERSION(0, 16))		\
1688 	x(subvol_dirent,		BCH_VERSION(0, 17))		\
1689 	x(inode_v2,			BCH_VERSION(0, 18))		\
1690 	x(freespace,			BCH_VERSION(0, 19))		\
1691 	x(alloc_v4,			BCH_VERSION(0, 20))		\
1692 	x(new_data_types,		BCH_VERSION(0, 21))		\
1693 	x(backpointers,			BCH_VERSION(0, 22))		\
1694 	x(inode_v3,			BCH_VERSION(0, 23))		\
1695 	x(unwritten_extents,		BCH_VERSION(0, 24))		\
1696 	x(bucket_gens,			BCH_VERSION(0, 25))		\
1697 	x(lru_v2,			BCH_VERSION(0, 26))		\
1698 	x(fragmentation_lru,		BCH_VERSION(0, 27))		\
1699 	x(no_bps_in_alloc_keys,		BCH_VERSION(0, 28))		\
1700 	x(snapshot_trees,		BCH_VERSION(0, 29))		\
1701 	x(major_minor,			BCH_VERSION(1,  0))		\
1702 	x(snapshot_skiplists,		BCH_VERSION(1,  1))		\
1703 	x(deleted_inodes,		BCH_VERSION(1,  2))		\
1704 	x(rebalance_work,		BCH_VERSION(1,  3))		\
1705 	x(member_seq,			BCH_VERSION(1,  4))
1706 
1707 enum bcachefs_metadata_version {
1708 	bcachefs_metadata_version_min = 9,
1709 #define x(t, n)	bcachefs_metadata_version_##t = n,
1710 	BCH_METADATA_VERSIONS()
1711 #undef x
1712 	bcachefs_metadata_version_max
1713 };
1714 
1715 static const __maybe_unused
1716 unsigned bcachefs_metadata_required_upgrade_below = bcachefs_metadata_version_rebalance_work;
1717 
1718 #define bcachefs_metadata_version_current	(bcachefs_metadata_version_max - 1)
1719 
1720 #define BCH_SB_SECTOR			8
1721 #define BCH_SB_MEMBERS_MAX		64 /* XXX kill */
1722 
1723 struct bch_sb_layout {
1724 	__uuid_t		magic;	/* bcachefs superblock UUID */
1725 	__u8			layout_type;
1726 	__u8			sb_max_size_bits; /* base 2 of 512 byte sectors */
1727 	__u8			nr_superblocks;
1728 	__u8			pad[5];
1729 	__le64			sb_offset[61];
1730 } __packed __aligned(8);
1731 
1732 #define BCH_SB_LAYOUT_SECTOR	7
1733 
1734 /*
1735  * @offset	- sector where this sb was written
1736  * @version	- on disk format version
1737  * @version_min	- Oldest metadata version this filesystem contains; so we can
1738  *		  safely drop compatibility code and refuse to mount filesystems
1739  *		  we'd need it for
1740  * @magic	- identifies as a bcachefs superblock (BCHFS_MAGIC)
1741  * @seq		- incremented each time superblock is written
1742  * @uuid	- used for generating various magic numbers and identifying
1743  *                member devices, never changes
1744  * @user_uuid	- user visible UUID, may be changed
1745  * @label	- filesystem label
1746  * @seq		- identifies most recent superblock, incremented each time
1747  *		  superblock is written
1748  * @features	- enabled incompatible features
1749  */
1750 struct bch_sb {
1751 	struct bch_csum		csum;
1752 	__le16			version;
1753 	__le16			version_min;
1754 	__le16			pad[2];
1755 	__uuid_t		magic;
1756 	__uuid_t		uuid;
1757 	__uuid_t		user_uuid;
1758 	__u8			label[BCH_SB_LABEL_SIZE];
1759 	__le64			offset;
1760 	__le64			seq;
1761 
1762 	__le16			block_size;
1763 	__u8			dev_idx;
1764 	__u8			nr_devices;
1765 	__le32			u64s;
1766 
1767 	__le64			time_base_lo;
1768 	__le32			time_base_hi;
1769 	__le32			time_precision;
1770 
1771 	__le64			flags[7];
1772 	__le64			write_time;
1773 	__le64			features[2];
1774 	__le64			compat[2];
1775 
1776 	struct bch_sb_layout	layout;
1777 
1778 	struct bch_sb_field	start[0];
1779 	__le64			_data[];
1780 } __packed __aligned(8);
1781 
1782 /*
1783  * Flags:
1784  * BCH_SB_INITALIZED	- set on first mount
1785  * BCH_SB_CLEAN		- did we shut down cleanly? Just a hint, doesn't affect
1786  *			  behaviour of mount/recovery path:
1787  * BCH_SB_INODE_32BIT	- limit inode numbers to 32 bits
1788  * BCH_SB_128_BIT_MACS	- 128 bit macs instead of 80
1789  * BCH_SB_ENCRYPTION_TYPE - if nonzero encryption is enabled; overrides
1790  *			   DATA/META_CSUM_TYPE. Also indicates encryption
1791  *			   algorithm in use, if/when we get more than one
1792  */
1793 
1794 LE16_BITMASK(BCH_SB_BLOCK_SIZE,		struct bch_sb, block_size, 0, 16);
1795 
1796 LE64_BITMASK(BCH_SB_INITIALIZED,	struct bch_sb, flags[0],  0,  1);
1797 LE64_BITMASK(BCH_SB_CLEAN,		struct bch_sb, flags[0],  1,  2);
1798 LE64_BITMASK(BCH_SB_CSUM_TYPE,		struct bch_sb, flags[0],  2,  8);
1799 LE64_BITMASK(BCH_SB_ERROR_ACTION,	struct bch_sb, flags[0],  8, 12);
1800 
1801 LE64_BITMASK(BCH_SB_BTREE_NODE_SIZE,	struct bch_sb, flags[0], 12, 28);
1802 
1803 LE64_BITMASK(BCH_SB_GC_RESERVE,		struct bch_sb, flags[0], 28, 33);
1804 LE64_BITMASK(BCH_SB_ROOT_RESERVE,	struct bch_sb, flags[0], 33, 40);
1805 
1806 LE64_BITMASK(BCH_SB_META_CSUM_TYPE,	struct bch_sb, flags[0], 40, 44);
1807 LE64_BITMASK(BCH_SB_DATA_CSUM_TYPE,	struct bch_sb, flags[0], 44, 48);
1808 
1809 LE64_BITMASK(BCH_SB_META_REPLICAS_WANT,	struct bch_sb, flags[0], 48, 52);
1810 LE64_BITMASK(BCH_SB_DATA_REPLICAS_WANT,	struct bch_sb, flags[0], 52, 56);
1811 
1812 LE64_BITMASK(BCH_SB_POSIX_ACL,		struct bch_sb, flags[0], 56, 57);
1813 LE64_BITMASK(BCH_SB_USRQUOTA,		struct bch_sb, flags[0], 57, 58);
1814 LE64_BITMASK(BCH_SB_GRPQUOTA,		struct bch_sb, flags[0], 58, 59);
1815 LE64_BITMASK(BCH_SB_PRJQUOTA,		struct bch_sb, flags[0], 59, 60);
1816 
1817 LE64_BITMASK(BCH_SB_HAS_ERRORS,		struct bch_sb, flags[0], 60, 61);
1818 LE64_BITMASK(BCH_SB_HAS_TOPOLOGY_ERRORS,struct bch_sb, flags[0], 61, 62);
1819 
1820 LE64_BITMASK(BCH_SB_BIG_ENDIAN,		struct bch_sb, flags[0], 62, 63);
1821 
1822 LE64_BITMASK(BCH_SB_STR_HASH_TYPE,	struct bch_sb, flags[1],  0,  4);
1823 LE64_BITMASK(BCH_SB_COMPRESSION_TYPE_LO,struct bch_sb, flags[1],  4,  8);
1824 LE64_BITMASK(BCH_SB_INODE_32BIT,	struct bch_sb, flags[1],  8,  9);
1825 
1826 LE64_BITMASK(BCH_SB_128_BIT_MACS,	struct bch_sb, flags[1],  9, 10);
1827 LE64_BITMASK(BCH_SB_ENCRYPTION_TYPE,	struct bch_sb, flags[1], 10, 14);
1828 
1829 /*
1830  * Max size of an extent that may require bouncing to read or write
1831  * (checksummed, compressed): 64k
1832  */
1833 LE64_BITMASK(BCH_SB_ENCODED_EXTENT_MAX_BITS,
1834 					struct bch_sb, flags[1], 14, 20);
1835 
1836 LE64_BITMASK(BCH_SB_META_REPLICAS_REQ,	struct bch_sb, flags[1], 20, 24);
1837 LE64_BITMASK(BCH_SB_DATA_REPLICAS_REQ,	struct bch_sb, flags[1], 24, 28);
1838 
1839 LE64_BITMASK(BCH_SB_PROMOTE_TARGET,	struct bch_sb, flags[1], 28, 40);
1840 LE64_BITMASK(BCH_SB_FOREGROUND_TARGET,	struct bch_sb, flags[1], 40, 52);
1841 LE64_BITMASK(BCH_SB_BACKGROUND_TARGET,	struct bch_sb, flags[1], 52, 64);
1842 
1843 LE64_BITMASK(BCH_SB_BACKGROUND_COMPRESSION_TYPE_LO,
1844 					struct bch_sb, flags[2],  0,  4);
1845 LE64_BITMASK(BCH_SB_GC_RESERVE_BYTES,	struct bch_sb, flags[2],  4, 64);
1846 
1847 LE64_BITMASK(BCH_SB_ERASURE_CODE,	struct bch_sb, flags[3],  0, 16);
1848 LE64_BITMASK(BCH_SB_METADATA_TARGET,	struct bch_sb, flags[3], 16, 28);
1849 LE64_BITMASK(BCH_SB_SHARD_INUMS,	struct bch_sb, flags[3], 28, 29);
1850 LE64_BITMASK(BCH_SB_INODES_USE_KEY_CACHE,struct bch_sb, flags[3], 29, 30);
1851 LE64_BITMASK(BCH_SB_JOURNAL_FLUSH_DELAY,struct bch_sb, flags[3], 30, 62);
1852 LE64_BITMASK(BCH_SB_JOURNAL_FLUSH_DISABLED,struct bch_sb, flags[3], 62, 63);
1853 LE64_BITMASK(BCH_SB_JOURNAL_RECLAIM_DELAY,struct bch_sb, flags[4], 0, 32);
1854 LE64_BITMASK(BCH_SB_JOURNAL_TRANSACTION_NAMES,struct bch_sb, flags[4], 32, 33);
1855 LE64_BITMASK(BCH_SB_NOCOW,		struct bch_sb, flags[4], 33, 34);
1856 LE64_BITMASK(BCH_SB_WRITE_BUFFER_SIZE,	struct bch_sb, flags[4], 34, 54);
1857 LE64_BITMASK(BCH_SB_VERSION_UPGRADE,	struct bch_sb, flags[4], 54, 56);
1858 
1859 LE64_BITMASK(BCH_SB_COMPRESSION_TYPE_HI,struct bch_sb, flags[4], 56, 60);
1860 LE64_BITMASK(BCH_SB_BACKGROUND_COMPRESSION_TYPE_HI,
1861 					struct bch_sb, flags[4], 60, 64);
1862 
1863 LE64_BITMASK(BCH_SB_VERSION_UPGRADE_COMPLETE,
1864 					struct bch_sb, flags[5],  0, 16);
1865 
1866 static inline __u64 BCH_SB_COMPRESSION_TYPE(const struct bch_sb *sb)
1867 {
1868 	return BCH_SB_COMPRESSION_TYPE_LO(sb) | (BCH_SB_COMPRESSION_TYPE_HI(sb) << 4);
1869 }
1870 
1871 static inline void SET_BCH_SB_COMPRESSION_TYPE(struct bch_sb *sb, __u64 v)
1872 {
1873 	SET_BCH_SB_COMPRESSION_TYPE_LO(sb, v);
1874 	SET_BCH_SB_COMPRESSION_TYPE_HI(sb, v >> 4);
1875 }
1876 
1877 static inline __u64 BCH_SB_BACKGROUND_COMPRESSION_TYPE(const struct bch_sb *sb)
1878 {
1879 	return BCH_SB_BACKGROUND_COMPRESSION_TYPE_LO(sb) |
1880 		(BCH_SB_BACKGROUND_COMPRESSION_TYPE_HI(sb) << 4);
1881 }
1882 
1883 static inline void SET_BCH_SB_BACKGROUND_COMPRESSION_TYPE(struct bch_sb *sb, __u64 v)
1884 {
1885 	SET_BCH_SB_BACKGROUND_COMPRESSION_TYPE_LO(sb, v);
1886 	SET_BCH_SB_BACKGROUND_COMPRESSION_TYPE_HI(sb, v >> 4);
1887 }
1888 
1889 /*
1890  * Features:
1891  *
1892  * journal_seq_blacklist_v3:	gates BCH_SB_FIELD_journal_seq_blacklist
1893  * reflink:			gates KEY_TYPE_reflink
1894  * inline_data:			gates KEY_TYPE_inline_data
1895  * new_siphash:			gates BCH_STR_HASH_siphash
1896  * new_extent_overwrite:	gates BTREE_NODE_NEW_EXTENT_OVERWRITE
1897  */
1898 #define BCH_SB_FEATURES()			\
1899 	x(lz4,				0)	\
1900 	x(gzip,				1)	\
1901 	x(zstd,				2)	\
1902 	x(atomic_nlink,			3)	\
1903 	x(ec,				4)	\
1904 	x(journal_seq_blacklist_v3,	5)	\
1905 	x(reflink,			6)	\
1906 	x(new_siphash,			7)	\
1907 	x(inline_data,			8)	\
1908 	x(new_extent_overwrite,		9)	\
1909 	x(incompressible,		10)	\
1910 	x(btree_ptr_v2,			11)	\
1911 	x(extents_above_btree_updates,	12)	\
1912 	x(btree_updates_journalled,	13)	\
1913 	x(reflink_inline_data,		14)	\
1914 	x(new_varint,			15)	\
1915 	x(journal_no_flush,		16)	\
1916 	x(alloc_v2,			17)	\
1917 	x(extents_across_btree_nodes,	18)
1918 
1919 #define BCH_SB_FEATURES_ALWAYS				\
1920 	((1ULL << BCH_FEATURE_new_extent_overwrite)|	\
1921 	 (1ULL << BCH_FEATURE_extents_above_btree_updates)|\
1922 	 (1ULL << BCH_FEATURE_btree_updates_journalled)|\
1923 	 (1ULL << BCH_FEATURE_alloc_v2)|\
1924 	 (1ULL << BCH_FEATURE_extents_across_btree_nodes))
1925 
1926 #define BCH_SB_FEATURES_ALL				\
1927 	(BCH_SB_FEATURES_ALWAYS|			\
1928 	 (1ULL << BCH_FEATURE_new_siphash)|		\
1929 	 (1ULL << BCH_FEATURE_btree_ptr_v2)|		\
1930 	 (1ULL << BCH_FEATURE_new_varint)|		\
1931 	 (1ULL << BCH_FEATURE_journal_no_flush))
1932 
1933 enum bch_sb_feature {
1934 #define x(f, n) BCH_FEATURE_##f,
1935 	BCH_SB_FEATURES()
1936 #undef x
1937 	BCH_FEATURE_NR,
1938 };
1939 
1940 #define BCH_SB_COMPAT()					\
1941 	x(alloc_info,				0)	\
1942 	x(alloc_metadata,			1)	\
1943 	x(extents_above_btree_updates_done,	2)	\
1944 	x(bformat_overflow_done,		3)
1945 
1946 enum bch_sb_compat {
1947 #define x(f, n) BCH_COMPAT_##f,
1948 	BCH_SB_COMPAT()
1949 #undef x
1950 	BCH_COMPAT_NR,
1951 };
1952 
1953 /* options: */
1954 
1955 #define BCH_VERSION_UPGRADE_OPTS()	\
1956 	x(compatible,		0)	\
1957 	x(incompatible,		1)	\
1958 	x(none,			2)
1959 
1960 enum bch_version_upgrade_opts {
1961 #define x(t, n) BCH_VERSION_UPGRADE_##t = n,
1962 	BCH_VERSION_UPGRADE_OPTS()
1963 #undef x
1964 };
1965 
1966 #define BCH_REPLICAS_MAX		4U
1967 
1968 #define BCH_BKEY_PTRS_MAX		16U
1969 
1970 #define BCH_ERROR_ACTIONS()		\
1971 	x(continue,		0)	\
1972 	x(ro,			1)	\
1973 	x(panic,		2)
1974 
1975 enum bch_error_actions {
1976 #define x(t, n) BCH_ON_ERROR_##t = n,
1977 	BCH_ERROR_ACTIONS()
1978 #undef x
1979 	BCH_ON_ERROR_NR
1980 };
1981 
1982 #define BCH_STR_HASH_TYPES()		\
1983 	x(crc32c,		0)	\
1984 	x(crc64,		1)	\
1985 	x(siphash_old,		2)	\
1986 	x(siphash,		3)
1987 
1988 enum bch_str_hash_type {
1989 #define x(t, n) BCH_STR_HASH_##t = n,
1990 	BCH_STR_HASH_TYPES()
1991 #undef x
1992 	BCH_STR_HASH_NR
1993 };
1994 
1995 #define BCH_STR_HASH_OPTS()		\
1996 	x(crc32c,		0)	\
1997 	x(crc64,		1)	\
1998 	x(siphash,		2)
1999 
2000 enum bch_str_hash_opts {
2001 #define x(t, n) BCH_STR_HASH_OPT_##t = n,
2002 	BCH_STR_HASH_OPTS()
2003 #undef x
2004 	BCH_STR_HASH_OPT_NR
2005 };
2006 
2007 #define BCH_CSUM_TYPES()			\
2008 	x(none,				0)	\
2009 	x(crc32c_nonzero,		1)	\
2010 	x(crc64_nonzero,		2)	\
2011 	x(chacha20_poly1305_80,		3)	\
2012 	x(chacha20_poly1305_128,	4)	\
2013 	x(crc32c,			5)	\
2014 	x(crc64,			6)	\
2015 	x(xxhash,			7)
2016 
2017 enum bch_csum_type {
2018 #define x(t, n) BCH_CSUM_##t = n,
2019 	BCH_CSUM_TYPES()
2020 #undef x
2021 	BCH_CSUM_NR
2022 };
2023 
2024 static const __maybe_unused unsigned bch_crc_bytes[] = {
2025 	[BCH_CSUM_none]				= 0,
2026 	[BCH_CSUM_crc32c_nonzero]		= 4,
2027 	[BCH_CSUM_crc32c]			= 4,
2028 	[BCH_CSUM_crc64_nonzero]		= 8,
2029 	[BCH_CSUM_crc64]			= 8,
2030 	[BCH_CSUM_xxhash]			= 8,
2031 	[BCH_CSUM_chacha20_poly1305_80]		= 10,
2032 	[BCH_CSUM_chacha20_poly1305_128]	= 16,
2033 };
2034 
2035 static inline _Bool bch2_csum_type_is_encryption(enum bch_csum_type type)
2036 {
2037 	switch (type) {
2038 	case BCH_CSUM_chacha20_poly1305_80:
2039 	case BCH_CSUM_chacha20_poly1305_128:
2040 		return true;
2041 	default:
2042 		return false;
2043 	}
2044 }
2045 
2046 #define BCH_CSUM_OPTS()			\
2047 	x(none,			0)	\
2048 	x(crc32c,		1)	\
2049 	x(crc64,		2)	\
2050 	x(xxhash,		3)
2051 
2052 enum bch_csum_opts {
2053 #define x(t, n) BCH_CSUM_OPT_##t = n,
2054 	BCH_CSUM_OPTS()
2055 #undef x
2056 	BCH_CSUM_OPT_NR
2057 };
2058 
2059 #define BCH_COMPRESSION_TYPES()		\
2060 	x(none,			0)	\
2061 	x(lz4_old,		1)	\
2062 	x(gzip,			2)	\
2063 	x(lz4,			3)	\
2064 	x(zstd,			4)	\
2065 	x(incompressible,	5)
2066 
2067 enum bch_compression_type {
2068 #define x(t, n) BCH_COMPRESSION_TYPE_##t = n,
2069 	BCH_COMPRESSION_TYPES()
2070 #undef x
2071 	BCH_COMPRESSION_TYPE_NR
2072 };
2073 
2074 #define BCH_COMPRESSION_OPTS()		\
2075 	x(none,		0)		\
2076 	x(lz4,		1)		\
2077 	x(gzip,		2)		\
2078 	x(zstd,		3)
2079 
2080 enum bch_compression_opts {
2081 #define x(t, n) BCH_COMPRESSION_OPT_##t = n,
2082 	BCH_COMPRESSION_OPTS()
2083 #undef x
2084 	BCH_COMPRESSION_OPT_NR
2085 };
2086 
2087 /*
2088  * Magic numbers
2089  *
2090  * The various other data structures have their own magic numbers, which are
2091  * xored with the first part of the cache set's UUID
2092  */
2093 
2094 #define BCACHE_MAGIC							\
2095 	UUID_INIT(0xc68573f6, 0x4e1a, 0x45ca,				\
2096 		  0x82, 0x65, 0xf5, 0x7f, 0x48, 0xba, 0x6d, 0x81)
2097 #define BCHFS_MAGIC							\
2098 	UUID_INIT(0xc68573f6, 0x66ce, 0x90a9,				\
2099 		  0xd9, 0x6a, 0x60, 0xcf, 0x80, 0x3d, 0xf7, 0xef)
2100 
2101 #define BCACHEFS_STATFS_MAGIC		0xca451a4e
2102 
2103 #define JSET_MAGIC		__cpu_to_le64(0x245235c1a3625032ULL)
2104 #define BSET_MAGIC		__cpu_to_le64(0x90135c78b99e07f5ULL)
2105 
2106 static inline __le64 __bch2_sb_magic(struct bch_sb *sb)
2107 {
2108 	__le64 ret;
2109 
2110 	memcpy(&ret, &sb->uuid, sizeof(ret));
2111 	return ret;
2112 }
2113 
2114 static inline __u64 __jset_magic(struct bch_sb *sb)
2115 {
2116 	return __le64_to_cpu(__bch2_sb_magic(sb) ^ JSET_MAGIC);
2117 }
2118 
2119 static inline __u64 __bset_magic(struct bch_sb *sb)
2120 {
2121 	return __le64_to_cpu(__bch2_sb_magic(sb) ^ BSET_MAGIC);
2122 }
2123 
2124 /* Journal */
2125 
2126 #define JSET_KEYS_U64s	(sizeof(struct jset_entry) / sizeof(__u64))
2127 
2128 #define BCH_JSET_ENTRY_TYPES()			\
2129 	x(btree_keys,		0)		\
2130 	x(btree_root,		1)		\
2131 	x(prio_ptrs,		2)		\
2132 	x(blacklist,		3)		\
2133 	x(blacklist_v2,		4)		\
2134 	x(usage,		5)		\
2135 	x(data_usage,		6)		\
2136 	x(clock,		7)		\
2137 	x(dev_usage,		8)		\
2138 	x(log,			9)		\
2139 	x(overwrite,		10)		\
2140 	x(write_buffer_keys,	11)
2141 
2142 enum {
2143 #define x(f, nr)	BCH_JSET_ENTRY_##f	= nr,
2144 	BCH_JSET_ENTRY_TYPES()
2145 #undef x
2146 	BCH_JSET_ENTRY_NR
2147 };
2148 
2149 static inline bool jset_entry_is_key(struct jset_entry *e)
2150 {
2151 	switch (e->type) {
2152 	case BCH_JSET_ENTRY_btree_keys:
2153 	case BCH_JSET_ENTRY_btree_root:
2154 	case BCH_JSET_ENTRY_overwrite:
2155 	case BCH_JSET_ENTRY_write_buffer_keys:
2156 		return true;
2157 	}
2158 
2159 	return false;
2160 }
2161 
2162 /*
2163  * Journal sequence numbers can be blacklisted: bsets record the max sequence
2164  * number of all the journal entries they contain updates for, so that on
2165  * recovery we can ignore those bsets that contain index updates newer that what
2166  * made it into the journal.
2167  *
2168  * This means that we can't reuse that journal_seq - we have to skip it, and
2169  * then record that we skipped it so that the next time we crash and recover we
2170  * don't think there was a missing journal entry.
2171  */
2172 struct jset_entry_blacklist {
2173 	struct jset_entry	entry;
2174 	__le64			seq;
2175 };
2176 
2177 struct jset_entry_blacklist_v2 {
2178 	struct jset_entry	entry;
2179 	__le64			start;
2180 	__le64			end;
2181 };
2182 
2183 #define BCH_FS_USAGE_TYPES()			\
2184 	x(reserved,		0)		\
2185 	x(inodes,		1)		\
2186 	x(key_version,		2)
2187 
2188 enum {
2189 #define x(f, nr)	BCH_FS_USAGE_##f	= nr,
2190 	BCH_FS_USAGE_TYPES()
2191 #undef x
2192 	BCH_FS_USAGE_NR
2193 };
2194 
2195 struct jset_entry_usage {
2196 	struct jset_entry	entry;
2197 	__le64			v;
2198 } __packed;
2199 
2200 struct jset_entry_data_usage {
2201 	struct jset_entry	entry;
2202 	__le64			v;
2203 	struct bch_replicas_entry_v1 r;
2204 } __packed;
2205 
2206 struct jset_entry_clock {
2207 	struct jset_entry	entry;
2208 	__u8			rw;
2209 	__u8			pad[7];
2210 	__le64			time;
2211 } __packed;
2212 
2213 struct jset_entry_dev_usage_type {
2214 	__le64			buckets;
2215 	__le64			sectors;
2216 	__le64			fragmented;
2217 } __packed;
2218 
2219 struct jset_entry_dev_usage {
2220 	struct jset_entry	entry;
2221 	__le32			dev;
2222 	__u32			pad;
2223 
2224 	__le64			_buckets_ec;		/* No longer used */
2225 	__le64			_buckets_unavailable;	/* No longer used */
2226 
2227 	struct jset_entry_dev_usage_type d[];
2228 };
2229 
2230 static inline unsigned jset_entry_dev_usage_nr_types(struct jset_entry_dev_usage *u)
2231 {
2232 	return (vstruct_bytes(&u->entry) - sizeof(struct jset_entry_dev_usage)) /
2233 		sizeof(struct jset_entry_dev_usage_type);
2234 }
2235 
2236 struct jset_entry_log {
2237 	struct jset_entry	entry;
2238 	u8			d[];
2239 } __packed __aligned(8);
2240 
2241 /*
2242  * On disk format for a journal entry:
2243  * seq is monotonically increasing; every journal entry has its own unique
2244  * sequence number.
2245  *
2246  * last_seq is the oldest journal entry that still has keys the btree hasn't
2247  * flushed to disk yet.
2248  *
2249  * version is for on disk format changes.
2250  */
2251 struct jset {
2252 	struct bch_csum		csum;
2253 
2254 	__le64			magic;
2255 	__le64			seq;
2256 	__le32			version;
2257 	__le32			flags;
2258 
2259 	__le32			u64s; /* size of d[] in u64s */
2260 
2261 	__u8			encrypted_start[0];
2262 
2263 	__le16			_read_clock; /* no longer used */
2264 	__le16			_write_clock;
2265 
2266 	/* Sequence number of oldest dirty journal entry */
2267 	__le64			last_seq;
2268 
2269 
2270 	struct jset_entry	start[0];
2271 	__u64			_data[];
2272 } __packed __aligned(8);
2273 
2274 LE32_BITMASK(JSET_CSUM_TYPE,	struct jset, flags, 0, 4);
2275 LE32_BITMASK(JSET_BIG_ENDIAN,	struct jset, flags, 4, 5);
2276 LE32_BITMASK(JSET_NO_FLUSH,	struct jset, flags, 5, 6);
2277 
2278 #define BCH_JOURNAL_BUCKETS_MIN		8
2279 
2280 /* Btree: */
2281 
2282 enum btree_id_flags {
2283 	BTREE_ID_EXTENTS	= BIT(0),
2284 	BTREE_ID_SNAPSHOTS	= BIT(1),
2285 	BTREE_ID_SNAPSHOT_FIELD	= BIT(2),
2286 	BTREE_ID_DATA		= BIT(3),
2287 };
2288 
2289 #define BCH_BTREE_IDS()								\
2290 	x(extents,		0,	BTREE_ID_EXTENTS|BTREE_ID_SNAPSHOTS|BTREE_ID_DATA,\
2291 	  BIT_ULL(KEY_TYPE_whiteout)|						\
2292 	  BIT_ULL(KEY_TYPE_error)|						\
2293 	  BIT_ULL(KEY_TYPE_cookie)|						\
2294 	  BIT_ULL(KEY_TYPE_extent)|						\
2295 	  BIT_ULL(KEY_TYPE_reservation)|					\
2296 	  BIT_ULL(KEY_TYPE_reflink_p)|						\
2297 	  BIT_ULL(KEY_TYPE_inline_data))					\
2298 	x(inodes,		1,	BTREE_ID_SNAPSHOTS,			\
2299 	  BIT_ULL(KEY_TYPE_whiteout)|						\
2300 	  BIT_ULL(KEY_TYPE_inode)|						\
2301 	  BIT_ULL(KEY_TYPE_inode_v2)|						\
2302 	  BIT_ULL(KEY_TYPE_inode_v3)|						\
2303 	  BIT_ULL(KEY_TYPE_inode_generation))					\
2304 	x(dirents,		2,	BTREE_ID_SNAPSHOTS,			\
2305 	  BIT_ULL(KEY_TYPE_whiteout)|						\
2306 	  BIT_ULL(KEY_TYPE_hash_whiteout)|					\
2307 	  BIT_ULL(KEY_TYPE_dirent))						\
2308 	x(xattrs,		3,	BTREE_ID_SNAPSHOTS,			\
2309 	  BIT_ULL(KEY_TYPE_whiteout)|						\
2310 	  BIT_ULL(KEY_TYPE_cookie)|						\
2311 	  BIT_ULL(KEY_TYPE_hash_whiteout)|					\
2312 	  BIT_ULL(KEY_TYPE_xattr))						\
2313 	x(alloc,		4,	0,					\
2314 	  BIT_ULL(KEY_TYPE_alloc)|						\
2315 	  BIT_ULL(KEY_TYPE_alloc_v2)|						\
2316 	  BIT_ULL(KEY_TYPE_alloc_v3)|						\
2317 	  BIT_ULL(KEY_TYPE_alloc_v4))						\
2318 	x(quotas,		5,	0,					\
2319 	  BIT_ULL(KEY_TYPE_quota))						\
2320 	x(stripes,		6,	0,					\
2321 	  BIT_ULL(KEY_TYPE_stripe))						\
2322 	x(reflink,		7,	BTREE_ID_EXTENTS|BTREE_ID_DATA,		\
2323 	  BIT_ULL(KEY_TYPE_reflink_v)|						\
2324 	  BIT_ULL(KEY_TYPE_indirect_inline_data))				\
2325 	x(subvolumes,		8,	0,					\
2326 	  BIT_ULL(KEY_TYPE_subvolume))						\
2327 	x(snapshots,		9,	0,					\
2328 	  BIT_ULL(KEY_TYPE_snapshot))						\
2329 	x(lru,			10,	0,					\
2330 	  BIT_ULL(KEY_TYPE_set))						\
2331 	x(freespace,		11,	BTREE_ID_EXTENTS,			\
2332 	  BIT_ULL(KEY_TYPE_set))						\
2333 	x(need_discard,		12,	0,					\
2334 	  BIT_ULL(KEY_TYPE_set))						\
2335 	x(backpointers,		13,	0,					\
2336 	  BIT_ULL(KEY_TYPE_backpointer))					\
2337 	x(bucket_gens,		14,	0,					\
2338 	  BIT_ULL(KEY_TYPE_bucket_gens))					\
2339 	x(snapshot_trees,	15,	0,					\
2340 	  BIT_ULL(KEY_TYPE_snapshot_tree))					\
2341 	x(deleted_inodes,	16,	BTREE_ID_SNAPSHOT_FIELD,		\
2342 	  BIT_ULL(KEY_TYPE_set))						\
2343 	x(logged_ops,		17,	0,					\
2344 	  BIT_ULL(KEY_TYPE_logged_op_truncate)|					\
2345 	  BIT_ULL(KEY_TYPE_logged_op_finsert))					\
2346 	x(rebalance_work,	18,	BTREE_ID_SNAPSHOT_FIELD,		\
2347 	  BIT_ULL(KEY_TYPE_set)|BIT_ULL(KEY_TYPE_cookie))
2348 
2349 enum btree_id {
2350 #define x(name, nr, ...) BTREE_ID_##name = nr,
2351 	BCH_BTREE_IDS()
2352 #undef x
2353 	BTREE_ID_NR
2354 };
2355 
2356 #define BTREE_MAX_DEPTH		4U
2357 
2358 /* Btree nodes */
2359 
2360 /*
2361  * Btree nodes
2362  *
2363  * On disk a btree node is a list/log of these; within each set the keys are
2364  * sorted
2365  */
2366 struct bset {
2367 	__le64			seq;
2368 
2369 	/*
2370 	 * Highest journal entry this bset contains keys for.
2371 	 * If on recovery we don't see that journal entry, this bset is ignored:
2372 	 * this allows us to preserve the order of all index updates after a
2373 	 * crash, since the journal records a total order of all index updates
2374 	 * and anything that didn't make it to the journal doesn't get used.
2375 	 */
2376 	__le64			journal_seq;
2377 
2378 	__le32			flags;
2379 	__le16			version;
2380 	__le16			u64s; /* count of d[] in u64s */
2381 
2382 	struct bkey_packed	start[0];
2383 	__u64			_data[];
2384 } __packed __aligned(8);
2385 
2386 LE32_BITMASK(BSET_CSUM_TYPE,	struct bset, flags, 0, 4);
2387 
2388 LE32_BITMASK(BSET_BIG_ENDIAN,	struct bset, flags, 4, 5);
2389 LE32_BITMASK(BSET_SEPARATE_WHITEOUTS,
2390 				struct bset, flags, 5, 6);
2391 
2392 /* Sector offset within the btree node: */
2393 LE32_BITMASK(BSET_OFFSET,	struct bset, flags, 16, 32);
2394 
2395 struct btree_node {
2396 	struct bch_csum		csum;
2397 	__le64			magic;
2398 
2399 	/* this flags field is encrypted, unlike bset->flags: */
2400 	__le64			flags;
2401 
2402 	/* Closed interval: */
2403 	struct bpos		min_key;
2404 	struct bpos		max_key;
2405 	struct bch_extent_ptr	_ptr; /* not used anymore */
2406 	struct bkey_format	format;
2407 
2408 	union {
2409 	struct bset		keys;
2410 	struct {
2411 		__u8		pad[22];
2412 		__le16		u64s;
2413 		__u64		_data[0];
2414 
2415 	};
2416 	};
2417 } __packed __aligned(8);
2418 
2419 LE64_BITMASK(BTREE_NODE_ID_LO,	struct btree_node, flags,  0,  4);
2420 LE64_BITMASK(BTREE_NODE_LEVEL,	struct btree_node, flags,  4,  8);
2421 LE64_BITMASK(BTREE_NODE_NEW_EXTENT_OVERWRITE,
2422 				struct btree_node, flags,  8,  9);
2423 LE64_BITMASK(BTREE_NODE_ID_HI,	struct btree_node, flags,  9, 25);
2424 /* 25-32 unused */
2425 LE64_BITMASK(BTREE_NODE_SEQ,	struct btree_node, flags, 32, 64);
2426 
2427 static inline __u64 BTREE_NODE_ID(struct btree_node *n)
2428 {
2429 	return BTREE_NODE_ID_LO(n) | (BTREE_NODE_ID_HI(n) << 4);
2430 }
2431 
2432 static inline void SET_BTREE_NODE_ID(struct btree_node *n, __u64 v)
2433 {
2434 	SET_BTREE_NODE_ID_LO(n, v);
2435 	SET_BTREE_NODE_ID_HI(n, v >> 4);
2436 }
2437 
2438 struct btree_node_entry {
2439 	struct bch_csum		csum;
2440 
2441 	union {
2442 	struct bset		keys;
2443 	struct {
2444 		__u8		pad[22];
2445 		__le16		u64s;
2446 		__u64		_data[0];
2447 	};
2448 	};
2449 } __packed __aligned(8);
2450 
2451 #endif /* _BCACHEFS_FORMAT_H */
2452