linux/fs/bcachefs/btree_key_cache.h
Kent Overstreet 12ce5b7df1 bcachefs: Btree key cache coherency
- Updates to non key cache iterators will now be transparently
   redirected to the key cache for cached btrees.

 - Except when creating new keys: then the update goes to underlying
   btree

For for iterating over a cached btree to work, we need to ensure that if
a key exists in the key cache, it also exists in the btree - otherwise
the iterator code will skip past it and not check the key cache.

Otherwise, for consistency, all updates should go to the same place -
the key cache.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2023-10-22 17:09:23 -04:00

48 lines
1.6 KiB
C

#ifndef _BCACHEFS_BTREE_KEY_CACHE_H
#define _BCACHEFS_BTREE_KEY_CACHE_H
static inline size_t bch2_nr_btree_keys_need_flush(struct bch_fs *c)
{
size_t nr_dirty = atomic_long_read(&c->btree_key_cache.nr_dirty);
size_t nr_keys = atomic_long_read(&c->btree_key_cache.nr_keys);
size_t max_dirty = 1024 + nr_keys / 2;
return max_t(ssize_t, 0, nr_dirty - max_dirty);
}
static inline bool bch2_btree_key_cache_must_wait(struct bch_fs *c)
{
size_t nr_dirty = atomic_long_read(&c->btree_key_cache.nr_dirty);
size_t nr_keys = atomic_long_read(&c->btree_key_cache.nr_keys);
size_t max_dirty = 4096 + (nr_keys * 3) / 4;
return nr_dirty > max_dirty;
}
int bch2_btree_key_cache_journal_flush(struct journal *,
struct journal_entry_pin *, u64);
struct bkey_cached *
bch2_btree_key_cache_find(struct bch_fs *, enum btree_id, struct bpos);
int bch2_btree_path_traverse_cached(struct btree_trans *, struct btree_path *,
unsigned);
bool bch2_btree_insert_key_cached(struct btree_trans *,
struct btree_path *, struct bkey_i *);
int bch2_btree_key_cache_flush(struct btree_trans *,
enum btree_id, struct bpos);
void bch2_btree_key_cache_drop(struct btree_trans *,
struct btree_path *);
void bch2_fs_btree_key_cache_exit(struct btree_key_cache *);
void bch2_fs_btree_key_cache_init_early(struct btree_key_cache *);
int bch2_fs_btree_key_cache_init(struct btree_key_cache *);
void bch2_btree_key_cache_to_text(struct printbuf *, struct btree_key_cache *);
void bch2_btree_key_cache_exit(void);
int __init bch2_btree_key_cache_init(void);
#endif /* _BCACHEFS_BTREE_KEY_CACHE_H */