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ae4fb17e86
gc_pos is now based on keys, not nodes, for invariantness w.r.t. splits and merges Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
86 lines
2.4 KiB
C
86 lines
2.4 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _BCACHEFS_BTREE_GC_H
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#define _BCACHEFS_BTREE_GC_H
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#include "bkey.h"
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#include "btree_gc_types.h"
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#include "btree_types.h"
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int bch2_check_topology(struct bch_fs *);
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int bch2_check_allocations(struct bch_fs *);
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/*
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* For concurrent mark and sweep (with other index updates), we define a total
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* ordering of _all_ references GC walks:
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*
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* Note that some references will have the same GC position as others - e.g.
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* everything within the same btree node; in those cases we're relying on
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* whatever locking exists for where those references live, i.e. the write lock
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* on a btree node.
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*
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* That locking is also required to ensure GC doesn't pass the updater in
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* between the updater adding/removing the reference and updating the GC marks;
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* without that, we would at best double count sometimes.
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*
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* That part is important - whenever calling bch2_mark_pointers(), a lock _must_
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* be held that prevents GC from passing the position the updater is at.
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*
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* (What about the start of gc, when we're clearing all the marks? GC clears the
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* mark with the gc pos seqlock held, and bch_mark_bucket checks against the gc
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* position inside its cmpxchg loop, so crap magically works).
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*/
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/* Position of (the start of) a gc phase: */
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static inline struct gc_pos gc_phase(enum gc_phase phase)
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{
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return (struct gc_pos) { .phase = phase, };
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}
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static inline struct gc_pos gc_pos_btree(enum btree_id btree, unsigned level,
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struct bpos pos)
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{
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return (struct gc_pos) {
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.phase = GC_PHASE_btree,
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.btree = btree,
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.level = level,
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.pos = pos,
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};
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}
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static inline int gc_btree_order(enum btree_id btree)
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{
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if (btree == BTREE_ID_alloc)
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return -2;
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if (btree == BTREE_ID_stripes)
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return -1;
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return btree;
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}
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static inline int gc_pos_cmp(struct gc_pos l, struct gc_pos r)
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{
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return cmp_int(l.phase, r.phase) ?:
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cmp_int(gc_btree_order(l.btree),
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gc_btree_order(r.btree)) ?:
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cmp_int(l.level, r.level) ?:
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bpos_cmp(l.pos, r.pos);
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}
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static inline bool gc_visited(struct bch_fs *c, struct gc_pos pos)
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{
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unsigned seq;
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bool ret;
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do {
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seq = read_seqcount_begin(&c->gc_pos_lock);
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ret = gc_pos_cmp(pos, c->gc_pos) <= 0;
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} while (read_seqcount_retry(&c->gc_pos_lock, seq));
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return ret;
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}
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int bch2_gc_gens(struct bch_fs *);
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void bch2_gc_gens_async(struct bch_fs *);
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void bch2_fs_gc_init(struct bch_fs *);
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#endif /* _BCACHEFS_BTREE_GC_H */
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