linux-stable/fs/bcachefs/lru.c
Kent Overstreet d326ab2f5d bcachefs: LRU btree
This implements new persistent LRUs, to be used for buckets containing
cached data, as well as stripes ordered by time when a block became
empty.

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
2023-10-22 17:09:29 -04:00

120 lines
2.4 KiB
C

// SPDX-License-Identifier: GPL-2.0
#include "bcachefs.h"
#include "btree_iter.h"
#include "btree_update.h"
#include "error.h"
#include "lru.h"
const char *bch2_lru_invalid(const struct bch_fs *c, struct bkey_s_c k)
{
const struct bch_lru *lru = bkey_s_c_to_lru(k).v;
if (bkey_val_bytes(k.k) < sizeof(*lru))
return "incorrect value size";
return NULL;
}
void bch2_lru_to_text(struct printbuf *out, struct bch_fs *c,
struct bkey_s_c k)
{
const struct bch_lru *lru = bkey_s_c_to_lru(k).v;
pr_buf(out, "idx %llu", le64_to_cpu(lru->idx));
}
static int lru_delete(struct btree_trans *trans, u64 id, u64 idx, u64 time)
{
struct bch_fs *c = trans->c;
struct btree_iter iter;
struct bkey_s_c k;
u64 existing_idx;
int ret = 0;
if (!time)
return 0;
bch2_trans_iter_init(trans, &iter, BTREE_ID_lru,
POS(id, time),
BTREE_ITER_INTENT|
BTREE_ITER_WITH_UPDATES);
k = bch2_btree_iter_peek_slot(&iter);
ret = bkey_err(k);
if (ret)
goto err;
if (k.k->type != KEY_TYPE_lru) {
bch2_fs_inconsistent(c,
"pointer to nonexistent lru %llu:%llu",
id, time);
ret = -EIO;
goto err;
}
existing_idx = le64_to_cpu(bkey_s_c_to_lru(k).v->idx);
if (existing_idx != idx) {
bch2_fs_inconsistent(c,
"lru %llu:%llu with wrong backpointer: got %llu, should be %llu",
id, time, existing_idx, idx);
ret = -EIO;
goto err;
}
ret = bch2_btree_delete_at(trans, &iter, 0);
err:
bch2_trans_iter_exit(trans, &iter);
return ret;
}
static int lru_set(struct btree_trans *trans, u64 lru_id, u64 idx, u64 *time)
{
struct btree_iter iter;
struct bkey_s_c k;
struct bkey_i_lru *lru;
int ret = 0;
if (!*time)
return 0;
for_each_btree_key_norestart(trans, iter, BTREE_ID_lru,
POS(lru_id, *time),
BTREE_ITER_SLOTS|
BTREE_ITER_INTENT|
BTREE_ITER_WITH_UPDATES, k, ret)
if (bkey_deleted(k.k))
break;
if (ret)
goto err;
BUG_ON(iter.pos.inode != lru_id);
*time = iter.pos.offset;
lru = bch2_trans_kmalloc(trans, sizeof(*lru));
ret = PTR_ERR_OR_ZERO(lru);
if (ret)
goto err;
bkey_lru_init(&lru->k_i);
lru->k.p = iter.pos;
lru->v.idx = cpu_to_le64(idx);
ret = bch2_trans_update(trans, &iter, &lru->k_i, 0);
if (ret)
goto err;
err:
bch2_trans_iter_exit(trans, &iter);
return ret;
}
int bch2_lru_change(struct btree_trans *trans, u64 id, u64 idx,
u64 old_time, u64 *new_time)
{
if (old_time == *new_time)
return 0;
return lru_delete(trans, id, idx, old_time) ?:
lru_set(trans, id, idx, new_time);
}