linux-next/fs/bcachefs/btree_journal_iter.h
Kent Overstreet 92084feca4 bcachefs: fix O(n^2) issue with whiteouts in journal keys
The journal_keys array can't be substantially modified after we go RW,
because lookups need to be able to check it locklessly - thus we're
limited on what we can do when a key in the journal has been
overwritten.

This is a problem when there's many overwrites to skip over for peek()
operations. To fix this, add tracking of ranges of overwrites: we create
a range entry when there's more than one contiguous whiteout.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2024-12-08 23:56:19 -05:00

103 lines
3.2 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _BCACHEFS_BTREE_JOURNAL_ITER_H
#define _BCACHEFS_BTREE_JOURNAL_ITER_H
#include "bkey.h"
struct journal_iter {
struct list_head list;
enum btree_id btree_id;
unsigned level;
size_t idx;
struct journal_keys *keys;
};
/*
* Iterate over keys in the btree, with keys from the journal overlaid on top:
*/
struct btree_and_journal_iter {
struct btree_trans *trans;
struct btree *b;
struct btree_node_iter node_iter;
struct bkey unpacked;
struct journal_iter journal;
struct bpos pos;
bool at_end;
bool prefetch;
bool fail_if_too_many_whiteouts;
};
static inline int __journal_key_btree_cmp(enum btree_id l_btree_id,
unsigned l_level,
const struct journal_key *r)
{
return -cmp_int(l_level, r->level) ?:
cmp_int(l_btree_id, r->btree_id);
}
static inline int __journal_key_cmp(enum btree_id l_btree_id,
unsigned l_level,
struct bpos l_pos,
const struct journal_key *r)
{
return __journal_key_btree_cmp(l_btree_id, l_level, r) ?:
bpos_cmp(l_pos, r->k->k.p);
}
static inline int journal_key_cmp(const struct journal_key *l, const struct journal_key *r)
{
return __journal_key_cmp(l->btree_id, l->level, l->k->k.p, r);
}
struct bkey_i *bch2_journal_keys_peek_max(struct bch_fs *, enum btree_id,
unsigned, struct bpos, struct bpos, size_t *);
struct bkey_i *bch2_journal_keys_peek_prev_min(struct bch_fs *, enum btree_id,
unsigned, struct bpos, struct bpos, size_t *);
struct bkey_i *bch2_journal_keys_peek_slot(struct bch_fs *, enum btree_id,
unsigned, struct bpos);
int bch2_btree_and_journal_iter_prefetch(struct btree_trans *, struct btree_path *,
struct btree_and_journal_iter *);
int bch2_journal_key_insert_take(struct bch_fs *, enum btree_id,
unsigned, struct bkey_i *);
int bch2_journal_key_insert(struct bch_fs *, enum btree_id,
unsigned, struct bkey_i *);
int bch2_journal_key_delete(struct bch_fs *, enum btree_id,
unsigned, struct bpos);
bool bch2_key_deleted_in_journal(struct btree_trans *, enum btree_id, unsigned, struct bpos);
void bch2_journal_key_overwritten(struct bch_fs *, enum btree_id, unsigned, struct bpos);
void bch2_btree_and_journal_iter_advance(struct btree_and_journal_iter *);
struct bkey_s_c bch2_btree_and_journal_iter_peek(struct btree_and_journal_iter *);
void bch2_btree_and_journal_iter_exit(struct btree_and_journal_iter *);
void __bch2_btree_and_journal_iter_init_node_iter(struct btree_trans *,
struct btree_and_journal_iter *, struct btree *,
struct btree_node_iter, struct bpos);
void bch2_btree_and_journal_iter_init_node_iter(struct btree_trans *,
struct btree_and_journal_iter *, struct btree *);
void bch2_journal_keys_put(struct bch_fs *);
static inline void bch2_journal_keys_put_initial(struct bch_fs *c)
{
if (c->journal_keys.initial_ref_held)
bch2_journal_keys_put(c);
c->journal_keys.initial_ref_held = false;
}
int bch2_journal_keys_sort(struct bch_fs *);
void bch2_shoot_down_journal_keys(struct bch_fs *, enum btree_id,
unsigned, unsigned,
struct bpos, struct bpos);
void bch2_journal_keys_dump(struct bch_fs *);
void bch2_fs_journal_keys_init(struct bch_fs *);
#endif /* _BCACHEFS_BTREE_JOURNAL_ITER_H */