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-rw-r--r--fs/bcachefs/str_hash.h370
1 files changed, 370 insertions, 0 deletions
diff --git a/fs/bcachefs/str_hash.h b/fs/bcachefs/str_hash.h
new file mode 100644
index 0000000000..ae21a8cca1
--- /dev/null
+++ b/fs/bcachefs/str_hash.h
@@ -0,0 +1,370 @@
+/* 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 int
+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,
+ unsigned flags)
+{
+ 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|flags, k, ret) {
+ if (is_visible_key(desc, inum, k)) {
+ if (!desc.cmp_key(k, key))
+ return 0;
+ } else if (k.k->type == KEY_TYPE_hash_whiteout) {
+ ;
+ } else {
+ /* hole, not found */
+ break;
+ }
+ }
+ bch2_trans_iter_exit(trans, iter);
+
+ return ret ?: -BCH_ERR_ENOENT_str_hash_lookup;
+}
+
+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_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,
+ int flags,
+ int update_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, 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 & BCH_HASH_SET_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 & BCH_HASH_SET_MUST_REPLACE)) {
+ ret = -BCH_ERR_ENOENT_str_hash_set_must_replace;
+ } else if (found && (flags & BCH_HASH_SET_MUST_CREATE)) {
+ ret = -EEXIST;
+ } else {
+ if (!found && slot.path)
+ swap(iter, slot);
+
+ insert->k.p = iter.pos;
+ ret = bch2_trans_update(trans, &iter, insert, 0);
+ }
+
+ 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, int flags)
+{
+ u32 snapshot;
+ int ret;
+
+ ret = bch2_subvolume_get_snapshot(trans, inum.subvol, &snapshot);
+ if (ret)
+ return ret;
+
+ insert->k.p.inode = inum.inum;
+
+ return bch2_hash_set_snapshot(trans, desc, info, inum,
+ snapshot, insert, flags, 0);
+}
+
+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,
+ unsigned update_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, update_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;
+ int ret;
+
+ ret = bch2_hash_lookup(trans, &iter, desc, info, inum, key,
+ BTREE_ITER_INTENT);
+ if (ret)
+ return ret;
+
+ ret = bch2_hash_delete_at(trans, desc, info, &iter, 0);
+ bch2_trans_iter_exit(trans, &iter);
+ return ret;
+}
+
+#endif /* _BCACHEFS_STR_HASH_H */
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-06 01:43:48 +0000