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author | Kent Overstreet <kent.overstreet@gmail.com> | 2021-12-05 08:31:54 +0300 |
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committer | Kent Overstreet <kent.overstreet@linux.dev> | 2023-10-23 00:09:29 +0300 |
commit | d326ab2f5de201b9b7e790c653a2b925e7032d3b (patch) | |
tree | 228f5e7af8165a24b890ffbc7501513dbfd24e63 /fs/bcachefs/lru.c | |
parent | 179e3434fac14a100bad2edba4fd401bffb67802 (diff) | |
download | linux-d326ab2f5de201b9b7e790c653a2b925e7032d3b.tar.xz |
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>
Diffstat (limited to 'fs/bcachefs/lru.c')
-rw-r--r-- | fs/bcachefs/lru.c | 119 |
1 files changed, 119 insertions, 0 deletions
diff --git a/fs/bcachefs/lru.c b/fs/bcachefs/lru.c new file mode 100644 index 000000000000..2ababca5efe5 --- /dev/null +++ b/fs/bcachefs/lru.c @@ -0,0 +1,119 @@ +// 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); +} |