/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _BCACHEFS_STR_HASH_H
#define _BCACHEFS_STR_HASH_H
#include "btree_iter.h"
#include "btree_update.h"
#include "checksum.h"
#include "error.h"
#include "inode.h"
#include "siphash.h"
#include "subvolume.h"
#include "super.h"
#include <linux/crc32c.h>
#include <crypto/hash.h>
#include <crypto/sha2.h>
static inline enum bch_str_hash_type
bch2_str_hash_opt_to_type(struct bch_fs *c, enum bch_str_hash_opts opt)
{
switch (opt) {
case BCH_STR_HASH_OPT_crc32c:
return BCH_STR_HASH_crc32c;
case BCH_STR_HASH_OPT_crc64:
return BCH_STR_HASH_crc64;
case BCH_STR_HASH_OPT_siphash:
return c->sb.features & (1ULL << BCH_FEATURE_new_siphash)
? BCH_STR_HASH_siphash
: BCH_STR_HASH_siphash_old;
default:
BUG();
}
}
struct bch_hash_info {
u8 type;
/*
* For crc32 or crc64 string hashes the first key value of
* the siphash_key (k0) is used as the key.
*/
SIPHASH_KEY siphash_key;
};
static inline struct bch_hash_info
bch2_hash_info_init(struct bch_fs *c, const struct bch_inode_unpacked *bi)
{
/* XXX ick */
struct bch_hash_info info = {
.type = (bi->bi_flags >> INODE_STR_HASH_OFFSET) &
~(~0U << INODE_STR_HASH_BITS),
.siphash_key = { .k0 = bi->bi_hash_seed }
};
if (unlikely(info.type == BCH_STR_HASH_siphash_old)) {
SHASH_DESC_ON_STACK(desc, c->sha256);
u8 digest[SHA256_DIGEST_SIZE];
desc->tfm = c->sha256;
crypto_shash_digest(desc, (void *) &bi->bi_hash_seed,
sizeof(bi->bi_hash_seed), digest);
memcpy(&info.siphash_key, digest, sizeof(info.siphash_key));
}
return info;
}
struct bch_str_hash_ctx {
union {
u32 crc32c;
u64 crc64;
SIPHASH_CTX siphash;
};
};
static inline void bch2_str_hash_init(struct bch_str_hash_ctx *ctx,
const struct bch_hash_info *info)
{
switch (info->type) {
case BCH_STR_HASH_crc32c:
ctx->crc32c = crc32c(~0, &info->siphash_key.k0,
sizeof(info->siphash_key.k0));
break;
case BCH_STR_HASH_crc64:
ctx->crc64 = crc64_be(~0, &info->siphash_key.k0,
sizeof(info->siphash_key.k0));
break;
case BCH_STR_HASH_siphash_old:
case BCH_STR_HASH_siphash:
SipHash24_Init(&ctx->siphash, &info->siphash_key);
break;
default:
BUG();
}
}
static inline void bch2_str_hash_update(struct bch_str_hash_ctx *ctx,
const struct bch_hash_info *info,
const void *data, size_t len)
{
switch (info->type) {
case BCH_STR_HASH_crc32c:
ctx->crc32c = crc32c(ctx->crc32c, data, len);
break;
case BCH_STR_HASH_crc64:
ctx->crc64 = crc64_be(ctx->crc64, data, len);
break;
case BCH_STR_HASH_siphash_old:
case BCH_STR_HASH_siphash:
SipHash24_Update(&ctx->siphash, data, len);
break;
default:
BUG();
}
}
static inline u64 bch2_str_hash_end(struct bch_str_hash_ctx *ctx,
const struct bch_hash_info *info)
{
switch (info->type) {
case BCH_STR_HASH_crc32c:
return ctx->crc32c;
case BCH_STR_HASH_crc64:
return ctx->crc64 >> 1;
case BCH_STR_HASH_siphash_old:
case BCH_STR_HASH_siphash:
return SipHash24_End(&ctx->siphash) >> 1;
default:
BUG();
}
}
struct bch_hash_desc {
enum btree_id btree_id;
u8 key_type;
u64 (*hash_key)(const struct bch_hash_info *, const void *);
u64 (*hash_bkey)(const struct bch_hash_info *, struct bkey_s_c);
bool (*cmp_key)(struct bkey_s_c, const void *);
bool (*cmp_bkey)(struct bkey_s_c, struct bkey_s_c);
bool (*is_visible)(subvol_inum inum, struct bkey_s_c);
};
static inline bool is_visible_key(struct bch_hash_desc desc, subvol_inum inum, struct bkey_s_c k)
{
return k.k->type == desc.key_type &&
(!desc.is_visible ||
!inum.inum ||
desc.is_visible(inum, k));
}
static __always_inline struct bkey_s_c
bch2_hash_lookup_in_snapshot(struct btree_trans *trans,
struct btree_iter *iter,
const struct bch_hash_desc desc,
const struct bch_hash_info *info,
subvol_inum inum, const void *key,
enum btree_iter_update_trigger_flags flags,
u32 snapshot)
{
struct bkey_s_c k;
int ret;
for_each_btree_key_upto_norestart(trans, *iter, desc.btree_id,
SPOS(inum.inum, desc.hash_key(info, key), snapshot),
POS(inum.inum, U64_MAX),
BTREE_ITER_slots|flags, k, ret) {
if (is_visible_key(desc, inum, k)) {
if (!desc.cmp_key(k, key))
return k;
} else if (k.k->type == KEY_TYPE_hash_whiteout) {
;
} else {
/* hole, not found */
break;
}
}
bch2_trans_iter_exit(trans, iter);
return bkey_s_c_err(ret ?: -BCH_ERR_ENOENT_str_hash_lookup);
}
static __always_inline struct bkey_s_c
bch2_hash_lookup(struct btree_trans *trans,
struct btree_iter *iter,
const struct bch_hash_desc desc,
const struct bch_hash_info *info,
subvol_inum inum, const void *key,
enum btree_iter_update_trigger_flags flags)
{
u32 snapshot;
int ret = bch2_subvolume_get_snapshot(trans, inum.subvol, &snapshot);
if (ret)
return bkey_s_c_err(ret);
return bch2_hash_lookup_in_snapshot(trans, iter, desc, info, inum, key, flags, snapshot);
}
static __always_inline int
bch2_hash_hole(struct btree_trans *trans,
struct btree_iter *iter,
const struct bch_hash_desc desc,
const struct bch_hash_info *info,
subvol_inum inum, const void *key)
{
struct bkey_s_c k;
u32 snapshot;
int ret;
ret = bch2_subvolume_get_snapshot(trans, inum.subvol, &snapshot);
if (ret)
return ret;
for_each_btree_key_upto_norestart(trans, *iter, desc.btree_id,
SPOS(inum.inum, desc.hash_key(info, key), snapshot),
POS(inum.inum, U64_MAX),
BTREE_ITER_slots|BTREE_ITER_intent, k, ret)
if (!is_visible_key(desc, inum, k))
return 0;
bch2_trans_iter_exit(trans, iter);
return ret ?: -BCH_ERR_ENOSPC_str_hash_create;
}
static __always_inline
int bch2_hash_needs_whiteout(struct btree_trans *trans,
const struct bch_hash_desc desc,
const struct bch_hash_info *info,
struct btree_iter *start)
{
struct btree_iter iter;
struct bkey_s_c k;
int ret;
bch2_trans_copy_iter(&iter, start);
bch2_btree_iter_advance(&iter);
for_each_btree_key_continue_norestart(iter, BTREE_ITER_slots, k, ret) {
if (k.k->type != desc.key_type &&
k.k->type != KEY_TYPE_hash_whiteout)
break;
if (k.k->type == desc.key_type &&
desc.hash_bkey(info, k) <= start->pos.offset) {
ret = 1;
break;
}
}
bch2_trans_iter_exit(trans, &iter);
return ret;
}
static __always_inline
int bch2_hash_set_in_snapshot(struct btree_trans *trans,
const struct bch_hash_desc desc,
const struct bch_hash_info *info,
subvol_inum inum, u32 snapshot,
struct bkey_i *insert,
enum btree_iter_update_trigger_flags flags)
{
struct btree_iter iter, slot = { NULL };
struct bkey_s_c k;
bool found = false;
int ret;
for_each_btree_key_upto_norestart(trans, iter, desc.btree_id,
SPOS(insert->k.p.inode,
desc.hash_bkey(info, bkey_i_to_s_c(insert)),
snapshot),
POS(insert->k.p.inode, U64_MAX),
BTREE_ITER_slots|BTREE_ITER_intent|flags, k, ret) {
if (is_visible_key(desc, inum, k)) {
if (!desc.cmp_bkey(k, bkey_i_to_s_c(insert)))
goto found;
/* hash collision: */
continue;
}
if (!slot.path && !(flags & STR_HASH_must_replace))
bch2_trans_copy_iter(&slot, &iter);
if (k.k->type != KEY_TYPE_hash_whiteout)
goto not_found;
}
if (!ret)
ret = -BCH_ERR_ENOSPC_str_hash_create;
out:
bch2_trans_iter_exit(trans, &slot);
bch2_trans_iter_exit(trans, &iter);
return ret;
found:
found = true;
not_found:
if (!found && (flags & STR_HASH_must_replace)) {
ret = -BCH_ERR_ENOENT_str_hash_set_must_replace;
} else if (found && (flags & STR_HASH_must_create)) {
ret = -BCH_ERR_EEXIST_str_hash_set;
} else {
if (!found && slot.path)
swap(iter, slot);
insert->k.p = iter.pos;
ret = bch2_trans_update(trans, &iter, insert, flags);
}
goto out;
}
static __always_inline
int bch2_hash_set(struct btree_trans *trans,
const struct bch_hash_desc desc,
const struct bch_hash_info *info,
subvol_inum inum,
struct bkey_i *insert,
enum btree_iter_update_trigger_flags flags)
{
insert->k.p.inode = inum.inum;
u32 snapshot;
return bch2_subvolume_get_snapshot(trans, inum.subvol, &snapshot) ?:
bch2_hash_set_in_snapshot(trans, desc, info, inum,
snapshot, insert, flags);
}
static __always_inline
int bch2_hash_delete_at(struct btree_trans *trans,
const struct bch_hash_desc desc,
const struct bch_hash_info *info,
struct btree_iter *iter,
enum btree_iter_update_trigger_flags flags)
{
struct bkey_i *delete;
int ret;
delete = bch2_trans_kmalloc(trans, sizeof(*delete));
ret = PTR_ERR_OR_ZERO(delete);
if (ret)
return ret;
ret = bch2_hash_needs_whiteout(trans, desc, info, iter);
if (ret < 0)
return ret;
bkey_init(&delete->k);
delete->k.p = iter->pos;
delete->k.type = ret ? KEY_TYPE_hash_whiteout : KEY_TYPE_deleted;
return bch2_trans_update(trans, iter, delete, flags);
}
static __always_inline
int bch2_hash_delete(struct btree_trans *trans,
const struct bch_hash_desc desc,
const struct bch_hash_info *info,
subvol_inum inum, const void *key)
{
struct btree_iter iter;
struct bkey_s_c k = bch2_hash_lookup(trans, &iter, desc, info, inum, key,
BTREE_ITER_intent);
int ret = bkey_err(k) ?:
bch2_hash_delete_at(trans, desc, info, &iter, 0);
bch2_trans_iter_exit(trans, &iter);
return ret;
}
#endif /* _BCACHEFS_STR_HASH_H */
Codebase Browser
linux