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1/* SPDX-License-Identifier: GPL-2.0 */2#ifndef _BCACHEFS_BTREE_GC_H3#define _BCACHEFS_BTREE_GC_H4 5#include "bkey.h"6#include "btree_gc_types.h"7#include "btree_types.h"8 9int bch2_check_topology(struct bch_fs *);10int bch2_check_allocations(struct bch_fs *);11 12/*13 * For concurrent mark and sweep (with other index updates), we define a total14 * ordering of _all_ references GC walks:15 *16 * Note that some references will have the same GC position as others - e.g.17 * everything within the same btree node; in those cases we're relying on18 * whatever locking exists for where those references live, i.e. the write lock19 * on a btree node.20 *21 * That locking is also required to ensure GC doesn't pass the updater in22 * between the updater adding/removing the reference and updating the GC marks;23 * without that, we would at best double count sometimes.24 *25 * That part is important - whenever calling bch2_mark_pointers(), a lock _must_26 * be held that prevents GC from passing the position the updater is at.27 *28 * (What about the start of gc, when we're clearing all the marks? GC clears the29 * mark with the gc pos seqlock held, and bch_mark_bucket checks against the gc30 * position inside its cmpxchg loop, so crap magically works).31 */32 33/* Position of (the start of) a gc phase: */34static inline struct gc_pos gc_phase(enum gc_phase phase)35{36 return (struct gc_pos) { .phase = phase, };37}38 39static inline struct gc_pos gc_pos_btree(enum btree_id btree, unsigned level,40 struct bpos pos)41{42 return (struct gc_pos) {43 .phase = GC_PHASE_btree,44 .btree = btree,45 .level = level,46 .pos = pos,47 };48}49 50static inline int gc_btree_order(enum btree_id btree)51{52 if (btree == BTREE_ID_alloc)53 return -2;54 if (btree == BTREE_ID_stripes)55 return -1;56 return btree;57}58 59static inline int gc_pos_cmp(struct gc_pos l, struct gc_pos r)60{61 return cmp_int(l.phase, r.phase) ?:62 cmp_int(gc_btree_order(l.btree),63 gc_btree_order(r.btree)) ?:64 cmp_int(l.level, r.level) ?:65 bpos_cmp(l.pos, r.pos);66}67 68static inline bool gc_visited(struct bch_fs *c, struct gc_pos pos)69{70 unsigned seq;71 bool ret;72 73 do {74 seq = read_seqcount_begin(&c->gc_pos_lock);75 ret = gc_pos_cmp(pos, c->gc_pos) <= 0;76 } while (read_seqcount_retry(&c->gc_pos_lock, seq));77 78 return ret;79}80 81void bch2_gc_pos_to_text(struct printbuf *, struct gc_pos *);82 83int bch2_gc_gens(struct bch_fs *);84void bch2_gc_gens_async(struct bch_fs *);85void bch2_fs_gc_init(struct bch_fs *);86 87#endif /* _BCACHEFS_BTREE_GC_H */88