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[bcachefs-tools-debian] / libbcachefs / btree_types.h
1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _BCACHEFS_BTREE_TYPES_H
3 #define _BCACHEFS_BTREE_TYPES_H
4
5 #include <linux/list.h>
6 #include <linux/rhashtable.h>
7
8 #include "btree_key_cache_types.h"
9 #include "buckets_types.h"
10 #include "darray.h"
11 #include "errcode.h"
12 #include "journal_types.h"
13 #include "replicas_types.h"
14 #include "six.h"
15
16 struct open_bucket;
17 struct btree_update;
18 struct btree_trans;
19
20 #define MAX_BSETS               3U
21
22 struct btree_nr_keys {
23
24         /*
25          * Amount of live metadata (i.e. size of node after a compaction) in
26          * units of u64s
27          */
28         u16                     live_u64s;
29         u16                     bset_u64s[MAX_BSETS];
30
31         /* live keys only: */
32         u16                     packed_keys;
33         u16                     unpacked_keys;
34 };
35
36 struct bset_tree {
37         /*
38          * We construct a binary tree in an array as if the array
39          * started at 1, so that things line up on the same cachelines
40          * better: see comments in bset.c at cacheline_to_bkey() for
41          * details
42          */
43
44         /* size of the binary tree and prev array */
45         u16                     size;
46
47         /* function of size - precalculated for to_inorder() */
48         u16                     extra;
49
50         u16                     data_offset;
51         u16                     aux_data_offset;
52         u16                     end_offset;
53 };
54
55 struct btree_write {
56         struct journal_entry_pin        journal;
57 };
58
59 struct btree_alloc {
60         struct open_buckets     ob;
61         __BKEY_PADDED(k, BKEY_BTREE_PTR_VAL_U64s_MAX);
62 };
63
64 struct btree_bkey_cached_common {
65         struct six_lock         lock;
66         u8                      level;
67         u8                      btree_id;
68         bool                    cached;
69 };
70
71 struct btree {
72         struct btree_bkey_cached_common c;
73
74         struct rhash_head       hash;
75         u64                     hash_val;
76
77         unsigned long           flags;
78         u16                     written;
79         u8                      nsets;
80         u8                      nr_key_bits;
81         u16                     version_ondisk;
82
83         struct bkey_format      format;
84
85         struct btree_node       *data;
86         void                    *aux_data;
87
88         /*
89          * Sets of sorted keys - the real btree node - plus a binary search tree
90          *
91          * set[0] is special; set[0]->tree, set[0]->prev and set[0]->data point
92          * to the memory we have allocated for this btree node. Additionally,
93          * set[0]->data points to the entire btree node as it exists on disk.
94          */
95         struct bset_tree        set[MAX_BSETS];
96
97         struct btree_nr_keys    nr;
98         u16                     sib_u64s[2];
99         u16                     whiteout_u64s;
100         u8                      byte_order;
101         u8                      unpack_fn_len;
102
103         struct btree_write      writes[2];
104
105         /* Key/pointer for this btree node */
106         __BKEY_PADDED(key, BKEY_BTREE_PTR_VAL_U64s_MAX);
107
108         /*
109          * XXX: add a delete sequence number, so when bch2_btree_node_relock()
110          * fails because the lock sequence number has changed - i.e. the
111          * contents were modified - we can still relock the node if it's still
112          * the one we want, without redoing the traversal
113          */
114
115         /*
116          * For asynchronous splits/interior node updates:
117          * When we do a split, we allocate new child nodes and update the parent
118          * node to point to them: we update the parent in memory immediately,
119          * but then we must wait until the children have been written out before
120          * the update to the parent can be written - this is a list of the
121          * btree_updates that are blocking this node from being
122          * written:
123          */
124         struct list_head        write_blocked;
125
126         /*
127          * Also for asynchronous splits/interior node updates:
128          * If a btree node isn't reachable yet, we don't want to kick off
129          * another write - because that write also won't yet be reachable and
130          * marking it as completed before it's reachable would be incorrect:
131          */
132         unsigned long           will_make_reachable;
133
134         struct open_buckets     ob;
135
136         /* lru list */
137         struct list_head        list;
138 };
139
140 struct btree_cache {
141         struct rhashtable       table;
142         bool                    table_init_done;
143         /*
144          * We never free a struct btree, except on shutdown - we just put it on
145          * the btree_cache_freed list and reuse it later. This simplifies the
146          * code, and it doesn't cost us much memory as the memory usage is
147          * dominated by buffers that hold the actual btree node data and those
148          * can be freed - and the number of struct btrees allocated is
149          * effectively bounded.
150          *
151          * btree_cache_freeable effectively is a small cache - we use it because
152          * high order page allocations can be rather expensive, and it's quite
153          * common to delete and allocate btree nodes in quick succession. It
154          * should never grow past ~2-3 nodes in practice.
155          */
156         struct mutex            lock;
157         struct list_head        live;
158         struct list_head        freeable;
159         struct list_head        freed_pcpu;
160         struct list_head        freed_nonpcpu;
161
162         /* Number of elements in live + freeable lists */
163         unsigned                used;
164         unsigned                reserve;
165         atomic_t                dirty;
166         struct shrinker         *shrink;
167
168         /*
169          * If we need to allocate memory for a new btree node and that
170          * allocation fails, we can cannibalize another node in the btree cache
171          * to satisfy the allocation - lock to guarantee only one thread does
172          * this at a time:
173          */
174         struct task_struct      *alloc_lock;
175         struct closure_waitlist alloc_wait;
176 };
177
178 struct btree_node_iter {
179         struct btree_node_iter_set {
180                 u16     k, end;
181         } data[MAX_BSETS];
182 };
183
184 /*
185  * Iterate over all possible positions, synthesizing deleted keys for holes:
186  */
187 static const __maybe_unused u16 BTREE_ITER_SLOTS                = 1 << 0;
188 /*
189  * Indicates that intent locks should be taken on leaf nodes, because we expect
190  * to be doing updates:
191  */
192 static const __maybe_unused u16 BTREE_ITER_INTENT               = 1 << 1;
193 /*
194  * Causes the btree iterator code to prefetch additional btree nodes from disk:
195  */
196 static const __maybe_unused u16 BTREE_ITER_PREFETCH             = 1 << 2;
197 /*
198  * Used in bch2_btree_iter_traverse(), to indicate whether we're searching for
199  * @pos or the first key strictly greater than @pos
200  */
201 static const __maybe_unused u16 BTREE_ITER_IS_EXTENTS           = 1 << 3;
202 static const __maybe_unused u16 BTREE_ITER_NOT_EXTENTS          = 1 << 4;
203 static const __maybe_unused u16 BTREE_ITER_CACHED               = 1 << 5;
204 static const __maybe_unused u16 BTREE_ITER_WITH_KEY_CACHE       = 1 << 6;
205 static const __maybe_unused u16 BTREE_ITER_WITH_UPDATES         = 1 << 7;
206 static const __maybe_unused u16 BTREE_ITER_WITH_JOURNAL         = 1 << 8;
207 static const __maybe_unused u16 __BTREE_ITER_ALL_SNAPSHOTS      = 1 << 9;
208 static const __maybe_unused u16 BTREE_ITER_ALL_SNAPSHOTS        = 1 << 10;
209 static const __maybe_unused u16 BTREE_ITER_FILTER_SNAPSHOTS     = 1 << 11;
210 static const __maybe_unused u16 BTREE_ITER_NOPRESERVE           = 1 << 12;
211 static const __maybe_unused u16 BTREE_ITER_CACHED_NOFILL        = 1 << 13;
212 static const __maybe_unused u16 BTREE_ITER_KEY_CACHE_FILL       = 1 << 14;
213 #define __BTREE_ITER_FLAGS_END                                         15
214
215 enum btree_path_uptodate {
216         BTREE_ITER_UPTODATE             = 0,
217         BTREE_ITER_NEED_RELOCK          = 1,
218         BTREE_ITER_NEED_TRAVERSE        = 2,
219 };
220
221 #if defined(CONFIG_BCACHEFS_LOCK_TIME_STATS) || defined(CONFIG_BCACHEFS_DEBUG)
222 #define TRACK_PATH_ALLOCATED
223 #endif
224
225 struct btree_path {
226         u8                      idx;
227         u8                      sorted_idx;
228         u8                      ref;
229         u8                      intent_ref;
230         u32                     alloc_seq;
231         u32                     downgrade_seq;
232
233         /* btree_iter_copy starts here: */
234         struct bpos             pos;
235
236         enum btree_id           btree_id:5;
237         bool                    cached:1;
238         bool                    preserve:1;
239         enum btree_path_uptodate uptodate:2;
240         /*
241          * When true, failing to relock this path will cause the transaction to
242          * restart:
243          */
244         bool                    should_be_locked:1;
245         unsigned                level:3,
246                                 locks_want:3;
247         u8                      nodes_locked;
248
249         struct btree_path_level {
250                 struct btree    *b;
251                 struct btree_node_iter iter;
252                 u32             lock_seq;
253 #ifdef CONFIG_BCACHEFS_LOCK_TIME_STATS
254                 u64             lock_taken_time;
255 #endif
256         }                       l[BTREE_MAX_DEPTH];
257 #ifdef TRACK_PATH_ALLOCATED
258         unsigned long           ip_allocated;
259 #endif
260 };
261
262 static inline struct btree_path_level *path_l(struct btree_path *path)
263 {
264         return path->l + path->level;
265 }
266
267 static inline unsigned long btree_path_ip_allocated(struct btree_path *path)
268 {
269 #ifdef TRACK_PATH_ALLOCATED
270         return path->ip_allocated;
271 #else
272         return _THIS_IP_;
273 #endif
274 }
275
276 /*
277  * @pos                 - iterator's current position
278  * @level               - current btree depth
279  * @locks_want          - btree level below which we start taking intent locks
280  * @nodes_locked        - bitmask indicating which nodes in @nodes are locked
281  * @nodes_intent_locked - bitmask indicating which locks are intent locks
282  */
283 struct btree_iter {
284         struct btree_trans      *trans;
285         struct btree_path       *path;
286         struct btree_path       *update_path;
287         struct btree_path       *key_cache_path;
288
289         enum btree_id           btree_id:8;
290         u8                      min_depth;
291
292         /* btree_iter_copy starts here: */
293         u16                     flags;
294
295         /* When we're filtering by snapshot, the snapshot ID we're looking for: */
296         unsigned                snapshot;
297
298         struct bpos             pos;
299         /*
300          * Current unpacked key - so that bch2_btree_iter_next()/
301          * bch2_btree_iter_next_slot() can correctly advance pos.
302          */
303         struct bkey             k;
304
305         /* BTREE_ITER_WITH_JOURNAL: */
306         size_t                  journal_idx;
307 #ifdef TRACK_PATH_ALLOCATED
308         unsigned long           ip_allocated;
309 #endif
310 };
311
312 #define BKEY_CACHED_ACCESSED            0
313 #define BKEY_CACHED_DIRTY               1
314
315 struct bkey_cached {
316         struct btree_bkey_cached_common c;
317
318         unsigned long           flags;
319         u16                     u64s;
320         bool                    valid;
321         u32                     btree_trans_barrier_seq;
322         struct bkey_cached_key  key;
323
324         struct rhash_head       hash;
325         struct list_head        list;
326
327         struct journal_entry_pin journal;
328         u64                     seq;
329
330         struct bkey_i           *k;
331 };
332
333 static inline struct bpos btree_node_pos(struct btree_bkey_cached_common *b)
334 {
335         return !b->cached
336                 ? container_of(b, struct btree, c)->key.k.p
337                 : container_of(b, struct bkey_cached, c)->key.pos;
338 }
339
340 struct btree_insert_entry {
341         unsigned                flags;
342         u8                      bkey_type;
343         enum btree_id           btree_id:8;
344         u8                      level:4;
345         bool                    cached:1;
346         bool                    insert_trigger_run:1;
347         bool                    overwrite_trigger_run:1;
348         bool                    key_cache_already_flushed:1;
349         /*
350          * @old_k may be a key from the journal; @old_btree_u64s always refers
351          * to the size of the key being overwritten in the btree:
352          */
353         u8                      old_btree_u64s;
354         struct bkey_i           *k;
355         struct btree_path       *path;
356         /* key being overwritten: */
357         struct bkey             old_k;
358         const struct bch_val    *old_v;
359         unsigned long           ip_allocated;
360 };
361
362 #define BTREE_ITER_MAX          64
363
364 struct btree_trans_commit_hook;
365 typedef int (btree_trans_commit_hook_fn)(struct btree_trans *, struct btree_trans_commit_hook *);
366
367 struct btree_trans_commit_hook {
368         btree_trans_commit_hook_fn      *fn;
369         struct btree_trans_commit_hook  *next;
370 };
371
372 #define BTREE_TRANS_MEM_MAX     (1U << 16)
373
374 #define BTREE_TRANS_MAX_LOCK_HOLD_TIME_NS       10000
375
376 struct btree_trans {
377         struct bch_fs           *c;
378         const char              *fn;
379         struct closure          ref;
380         struct list_head        list;
381         u64                     last_begin_time;
382
383         u8                      lock_may_not_fail;
384         u8                      lock_must_abort;
385         struct btree_bkey_cached_common *locking;
386         struct six_lock_waiter  locking_wait;
387
388         int                     srcu_idx;
389
390         u8                      fn_idx;
391         u8                      nr_sorted;
392         u8                      nr_updates;
393         u8                      nr_wb_updates;
394         u8                      wb_updates_size;
395         bool                    srcu_held:1;
396         bool                    used_mempool:1;
397         bool                    in_traverse_all:1;
398         bool                    paths_sorted:1;
399         bool                    memory_allocation_failure:1;
400         bool                    journal_transaction_names:1;
401         bool                    journal_replay_not_finished:1;
402         bool                    is_initial_gc:1;
403         bool                    notrace_relock_fail:1;
404         bool                    write_locked:1;
405         enum bch_errcode        restarted:16;
406         u32                     restart_count;
407         unsigned long           last_begin_ip;
408         unsigned long           last_restarted_ip;
409         unsigned long           srcu_lock_time;
410
411         /*
412          * For when bch2_trans_update notices we'll be splitting a compressed
413          * extent:
414          */
415         unsigned                extra_journal_res;
416         unsigned                nr_max_paths;
417
418         u64                     paths_allocated;
419
420         unsigned                mem_top;
421         unsigned                mem_max;
422         unsigned                mem_bytes;
423         void                    *mem;
424
425         u8                      sorted[BTREE_ITER_MAX + 8];
426         struct btree_path       paths[BTREE_ITER_MAX];
427         struct btree_insert_entry updates[BTREE_ITER_MAX];
428         struct btree_write_buffered_key *wb_updates;
429
430         /* update path: */
431         struct btree_trans_commit_hook *hooks;
432         darray_u64              extra_journal_entries;
433         struct journal_entry_pin *journal_pin;
434
435         struct journal_res      journal_res;
436         u64                     *journal_seq;
437         struct disk_reservation *disk_res;
438         unsigned                journal_u64s;
439         struct replicas_delta_list *fs_usage_deltas;
440 };
441
442 #define BCH_BTREE_WRITE_TYPES()                                         \
443         x(initial,              0)                                      \
444         x(init_next_bset,       1)                                      \
445         x(cache_reclaim,        2)                                      \
446         x(journal_reclaim,      3)                                      \
447         x(interior,             4)
448
449 enum btree_write_type {
450 #define x(t, n) BTREE_WRITE_##t,
451         BCH_BTREE_WRITE_TYPES()
452 #undef x
453         BTREE_WRITE_TYPE_NR,
454 };
455
456 #define BTREE_WRITE_TYPE_MASK   (roundup_pow_of_two(BTREE_WRITE_TYPE_NR) - 1)
457 #define BTREE_WRITE_TYPE_BITS   ilog2(roundup_pow_of_two(BTREE_WRITE_TYPE_NR))
458
459 #define BTREE_FLAGS()                                                   \
460         x(read_in_flight)                                               \
461         x(read_error)                                                   \
462         x(dirty)                                                        \
463         x(need_write)                                                   \
464         x(write_blocked)                                                \
465         x(will_make_reachable)                                          \
466         x(noevict)                                                      \
467         x(write_idx)                                                    \
468         x(accessed)                                                     \
469         x(write_in_flight)                                              \
470         x(write_in_flight_inner)                                        \
471         x(just_written)                                                 \
472         x(dying)                                                        \
473         x(fake)                                                         \
474         x(need_rewrite)                                                 \
475         x(never_write)
476
477 enum btree_flags {
478         /* First bits for btree node write type */
479         BTREE_NODE_FLAGS_START = BTREE_WRITE_TYPE_BITS - 1,
480 #define x(flag) BTREE_NODE_##flag,
481         BTREE_FLAGS()
482 #undef x
483 };
484
485 #define x(flag)                                                         \
486 static inline bool btree_node_ ## flag(struct btree *b)                 \
487 {       return test_bit(BTREE_NODE_ ## flag, &b->flags); }              \
488                                                                         \
489 static inline void set_btree_node_ ## flag(struct btree *b)             \
490 {       set_bit(BTREE_NODE_ ## flag, &b->flags); }                      \
491                                                                         \
492 static inline void clear_btree_node_ ## flag(struct btree *b)           \
493 {       clear_bit(BTREE_NODE_ ## flag, &b->flags); }
494
495 BTREE_FLAGS()
496 #undef x
497
498 static inline struct btree_write *btree_current_write(struct btree *b)
499 {
500         return b->writes + btree_node_write_idx(b);
501 }
502
503 static inline struct btree_write *btree_prev_write(struct btree *b)
504 {
505         return b->writes + (btree_node_write_idx(b) ^ 1);
506 }
507
508 static inline struct bset_tree *bset_tree_last(struct btree *b)
509 {
510         EBUG_ON(!b->nsets);
511         return b->set + b->nsets - 1;
512 }
513
514 static inline void *
515 __btree_node_offset_to_ptr(const struct btree *b, u16 offset)
516 {
517         return (void *) ((u64 *) b->data + 1 + offset);
518 }
519
520 static inline u16
521 __btree_node_ptr_to_offset(const struct btree *b, const void *p)
522 {
523         u16 ret = (u64 *) p - 1 - (u64 *) b->data;
524
525         EBUG_ON(__btree_node_offset_to_ptr(b, ret) != p);
526         return ret;
527 }
528
529 static inline struct bset *bset(const struct btree *b,
530                                 const struct bset_tree *t)
531 {
532         return __btree_node_offset_to_ptr(b, t->data_offset);
533 }
534
535 static inline void set_btree_bset_end(struct btree *b, struct bset_tree *t)
536 {
537         t->end_offset =
538                 __btree_node_ptr_to_offset(b, vstruct_last(bset(b, t)));
539 }
540
541 static inline void set_btree_bset(struct btree *b, struct bset_tree *t,
542                                   const struct bset *i)
543 {
544         t->data_offset = __btree_node_ptr_to_offset(b, i);
545         set_btree_bset_end(b, t);
546 }
547
548 static inline struct bset *btree_bset_first(struct btree *b)
549 {
550         return bset(b, b->set);
551 }
552
553 static inline struct bset *btree_bset_last(struct btree *b)
554 {
555         return bset(b, bset_tree_last(b));
556 }
557
558 static inline u16
559 __btree_node_key_to_offset(const struct btree *b, const struct bkey_packed *k)
560 {
561         return __btree_node_ptr_to_offset(b, k);
562 }
563
564 static inline struct bkey_packed *
565 __btree_node_offset_to_key(const struct btree *b, u16 k)
566 {
567         return __btree_node_offset_to_ptr(b, k);
568 }
569
570 static inline unsigned btree_bkey_first_offset(const struct bset_tree *t)
571 {
572         return t->data_offset + offsetof(struct bset, _data) / sizeof(u64);
573 }
574
575 #define btree_bkey_first(_b, _t)                                        \
576 ({                                                                      \
577         EBUG_ON(bset(_b, _t)->start !=                                  \
578                 __btree_node_offset_to_key(_b, btree_bkey_first_offset(_t)));\
579                                                                         \
580         bset(_b, _t)->start;                                            \
581 })
582
583 #define btree_bkey_last(_b, _t)                                         \
584 ({                                                                      \
585         EBUG_ON(__btree_node_offset_to_key(_b, (_t)->end_offset) !=     \
586                 vstruct_last(bset(_b, _t)));                            \
587                                                                         \
588         __btree_node_offset_to_key(_b, (_t)->end_offset);               \
589 })
590
591 static inline unsigned bset_u64s(struct bset_tree *t)
592 {
593         return t->end_offset - t->data_offset -
594                 sizeof(struct bset) / sizeof(u64);
595 }
596
597 static inline unsigned bset_dead_u64s(struct btree *b, struct bset_tree *t)
598 {
599         return bset_u64s(t) - b->nr.bset_u64s[t - b->set];
600 }
601
602 static inline unsigned bset_byte_offset(struct btree *b, void *i)
603 {
604         return i - (void *) b->data;
605 }
606
607 enum btree_node_type {
608         BKEY_TYPE_btree,
609 #define x(kwd, val, ...) BKEY_TYPE_##kwd = val + 1,
610         BCH_BTREE_IDS()
611 #undef x
612         BKEY_TYPE_NR
613 };
614
615 /* Type of a key in btree @id at level @level: */
616 static inline enum btree_node_type __btree_node_type(unsigned level, enum btree_id id)
617 {
618         return level ? BKEY_TYPE_btree : (unsigned) id + 1;
619 }
620
621 /* Type of keys @b contains: */
622 static inline enum btree_node_type btree_node_type(struct btree *b)
623 {
624         return __btree_node_type(b->c.level, b->c.btree_id);
625 }
626
627 const char *bch2_btree_node_type_str(enum btree_node_type);
628
629 #define BTREE_NODE_TYPE_HAS_TRANS_TRIGGERS              \
630         (BIT_ULL(BKEY_TYPE_extents)|                    \
631          BIT_ULL(BKEY_TYPE_alloc)|                      \
632          BIT_ULL(BKEY_TYPE_inodes)|                     \
633          BIT_ULL(BKEY_TYPE_stripes)|                    \
634          BIT_ULL(BKEY_TYPE_reflink)|                    \
635          BIT_ULL(BKEY_TYPE_btree))
636
637 #define BTREE_NODE_TYPE_HAS_MEM_TRIGGERS                \
638         (BIT_ULL(BKEY_TYPE_alloc)|                      \
639          BIT_ULL(BKEY_TYPE_inodes)|                     \
640          BIT_ULL(BKEY_TYPE_stripes)|                    \
641          BIT_ULL(BKEY_TYPE_snapshots))
642
643 #define BTREE_NODE_TYPE_HAS_TRIGGERS                    \
644         (BTREE_NODE_TYPE_HAS_TRANS_TRIGGERS|            \
645          BTREE_NODE_TYPE_HAS_MEM_TRIGGERS)
646
647 static inline bool btree_node_type_needs_gc(enum btree_node_type type)
648 {
649         return BTREE_NODE_TYPE_HAS_TRIGGERS & BIT_ULL(type);
650 }
651
652 static inline bool btree_node_type_is_extents(enum btree_node_type type)
653 {
654         const unsigned mask = 0
655 #define x(name, nr, flags, ...) |((!!((flags) & BTREE_ID_EXTENTS)) << (nr + 1))
656         BCH_BTREE_IDS()
657 #undef x
658         ;
659
660         return (1U << type) & mask;
661 }
662
663 static inline bool btree_id_is_extents(enum btree_id btree)
664 {
665         return btree_node_type_is_extents(__btree_node_type(0, btree));
666 }
667
668 static inline bool btree_type_has_snapshots(enum btree_id id)
669 {
670         const unsigned mask = 0
671 #define x(name, nr, flags, ...) |((!!((flags) & BTREE_ID_SNAPSHOTS)) << nr)
672         BCH_BTREE_IDS()
673 #undef x
674         ;
675
676         return (1U << id) & mask;
677 }
678
679 static inline bool btree_type_has_snapshot_field(enum btree_id id)
680 {
681         const unsigned mask = 0
682 #define x(name, nr, flags, ...) |((!!((flags) & (BTREE_ID_SNAPSHOT_FIELD|BTREE_ID_SNAPSHOTS))) << nr)
683         BCH_BTREE_IDS()
684 #undef x
685         ;
686
687         return (1U << id) & mask;
688 }
689
690 static inline bool btree_type_has_ptrs(enum btree_id id)
691 {
692         const unsigned mask = 0
693 #define x(name, nr, flags, ...) |((!!((flags) & BTREE_ID_DATA)) << nr)
694         BCH_BTREE_IDS()
695 #undef x
696         ;
697
698         return (1U << id) & mask;
699 }
700
701 struct btree_root {
702         struct btree            *b;
703
704         /* On disk root - see async splits: */
705         __BKEY_PADDED(key, BKEY_BTREE_PTR_VAL_U64s_MAX);
706         u8                      level;
707         u8                      alive;
708         s8                      error;
709 };
710
711 enum btree_gc_coalesce_fail_reason {
712         BTREE_GC_COALESCE_FAIL_RESERVE_GET,
713         BTREE_GC_COALESCE_FAIL_KEYLIST_REALLOC,
714         BTREE_GC_COALESCE_FAIL_FORMAT_FITS,
715 };
716
717 enum btree_node_sibling {
718         btree_prev_sib,
719         btree_next_sib,
720 };
721
722 #endif /* _BCACHEFS_BTREE_TYPES_H */