From 85c675d0d09a45a135bddd15d7b385f8758c32fb Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sat, 18 May 2024 19:35:05 +0200 Subject: Adding upstream version 6.7.7. Signed-off-by: Daniel Baumann --- fs/bcachefs/btree_gc.h | 114 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 114 insertions(+) create mode 100644 fs/bcachefs/btree_gc.h (limited to 'fs/bcachefs/btree_gc.h') diff --git a/fs/bcachefs/btree_gc.h b/fs/bcachefs/btree_gc.h new file mode 100644 index 000000000..607575f83 --- /dev/null +++ b/fs/bcachefs/btree_gc.h @@ -0,0 +1,114 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _BCACHEFS_BTREE_GC_H +#define _BCACHEFS_BTREE_GC_H + +#include "bkey.h" +#include "btree_types.h" + +int bch2_check_topology(struct bch_fs *); +int bch2_gc(struct bch_fs *, bool, bool); +int bch2_gc_gens(struct bch_fs *); +void bch2_gc_thread_stop(struct bch_fs *); +int bch2_gc_thread_start(struct bch_fs *); + +/* + * For concurrent mark and sweep (with other index updates), we define a total + * ordering of _all_ references GC walks: + * + * Note that some references will have the same GC position as others - e.g. + * everything within the same btree node; in those cases we're relying on + * whatever locking exists for where those references live, i.e. the write lock + * on a btree node. + * + * That locking is also required to ensure GC doesn't pass the updater in + * between the updater adding/removing the reference and updating the GC marks; + * without that, we would at best double count sometimes. + * + * That part is important - whenever calling bch2_mark_pointers(), a lock _must_ + * be held that prevents GC from passing the position the updater is at. + * + * (What about the start of gc, when we're clearing all the marks? GC clears the + * mark with the gc pos seqlock held, and bch_mark_bucket checks against the gc + * position inside its cmpxchg loop, so crap magically works). + */ + +/* Position of (the start of) a gc phase: */ +static inline struct gc_pos gc_phase(enum gc_phase phase) +{ + return (struct gc_pos) { + .phase = phase, + .pos = POS_MIN, + .level = 0, + }; +} + +static inline int gc_pos_cmp(struct gc_pos l, struct gc_pos r) +{ + return cmp_int(l.phase, r.phase) ?: + bpos_cmp(l.pos, r.pos) ?: + cmp_int(l.level, r.level); +} + +static inline enum gc_phase btree_id_to_gc_phase(enum btree_id id) +{ + switch (id) { +#define x(name, v, ...) case BTREE_ID_##name: return GC_PHASE_BTREE_##name; + BCH_BTREE_IDS() +#undef x + default: + BUG(); + } +} + +static inline struct gc_pos gc_pos_btree(enum btree_id id, + struct bpos pos, unsigned level) +{ + return (struct gc_pos) { + .phase = btree_id_to_gc_phase(id), + .pos = pos, + .level = level, + }; +} + +/* + * GC position of the pointers within a btree node: note, _not_ for &b->key + * itself, that lives in the parent node: + */ +static inline struct gc_pos gc_pos_btree_node(struct btree *b) +{ + return gc_pos_btree(b->c.btree_id, b->key.k.p, b->c.level); +} + +/* + * GC position of the pointer to a btree root: we don't use + * gc_pos_pointer_to_btree_node() here to avoid a potential race with + * btree_split() increasing the tree depth - the new root will have level > the + * old root and thus have a greater gc position than the old root, but that + * would be incorrect since once gc has marked the root it's not coming back. + */ +static inline struct gc_pos gc_pos_btree_root(enum btree_id id) +{ + return gc_pos_btree(id, SPOS_MAX, BTREE_MAX_DEPTH); +} + +static inline bool gc_visited(struct bch_fs *c, struct gc_pos pos) +{ + unsigned seq; + bool ret; + + do { + seq = read_seqcount_begin(&c->gc_pos_lock); + ret = gc_pos_cmp(pos, c->gc_pos) <= 0; + } while (read_seqcount_retry(&c->gc_pos_lock, seq)); + + return ret; +} + +static inline void bch2_do_gc_gens(struct bch_fs *c) +{ + atomic_inc(&c->kick_gc); + if (c->gc_thread) + wake_up_process(c->gc_thread); +} + +#endif /* _BCACHEFS_BTREE_GC_H */ -- cgit v1.2.3