bcachefs: Initial commit

Initially forked from drivers/md/bcache, bcachefs is a new copy-on-write
filesystem with every feature you could possibly want.

Website: https://bcachefs.org

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

1 files changed, 319 insertions, 0 deletions

diff --git a/fs/bcachefs/str_hash.h b/fs/bcachefs/str_hash.h
new file mode 100644
index 000000000000..0947fdcdc4cd
--- /dev/null
+++ b/fs/bcachefs/str_hash.h
@@ -0,0 +1,319 @@
+/* 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 "super.h"
+
+#include <linux/crc32c.h>
+#include <crypto/hash.h>
+#include <crypto/sha2.h>
+
+struct bch_hash_info {
+	u8			type;
+	union {
+		__le64		crc_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)
+	};
+
+	switch (info.type) {
+	case BCH_STR_HASH_CRC32C:
+	case BCH_STR_HASH_CRC64:
+		info.crc_key = bi->bi_hash_seed;
+		break;
+	case BCH_STR_HASH_SIPHASH: {
+		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));
+		break;
+	}
+	default:
+		BUG();
+	}
+
+	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->crc_key, sizeof(info->crc_key));
+		break;
+	case BCH_STR_HASH_CRC64:
+		ctx->crc64 = bch2_crc64_update(~0, &info->crc_key, sizeof(info->crc_key));
+		break;
+	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 = bch2_crc64_update(ctx->crc64, data, len);
+		break;
+	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:
+		return SipHash24_End(&ctx->siphash) >> 1;
+	default:
+		BUG();
+	}
+}
+
+struct bch_hash_desc {
+	enum btree_id	btree_id;
+	u8		key_type;
+	u8		whiteout_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);
+};
+
+static inline struct btree_iter *
+bch2_hash_lookup(struct btree_trans *trans,
+		 const struct bch_hash_desc desc,
+		 const struct bch_hash_info *info,
+		 u64 inode, const void *key,
+		 unsigned flags)
+{
+	struct btree_iter *iter;
+	struct bkey_s_c k;
+
+	iter = bch2_trans_get_iter(trans, desc.btree_id,
+				   POS(inode, desc.hash_key(info, key)),
+				   BTREE_ITER_SLOTS|flags);
+	if (IS_ERR(iter))
+		return iter;
+
+	for_each_btree_key_continue(iter, BTREE_ITER_SLOTS, k) {
+		if (iter->pos.inode != inode)
+			break;
+
+		if (k.k->type == desc.key_type) {
+			if (!desc.cmp_key(k, key))
+				return iter;
+		} else if (k.k->type == desc.whiteout_type) {
+			;
+		} else {
+			/* hole, not found */
+			break;
+		}
+	}
+
+	return IS_ERR(k.k) ? ERR_CAST(k.k) : ERR_PTR(-ENOENT);
+}
+
+static inline struct btree_iter *
+bch2_hash_hole(struct btree_trans *trans,
+	       const struct bch_hash_desc desc,
+	       const struct bch_hash_info *info,
+	       u64 inode, const void *key)
+{
+	struct btree_iter *iter;
+	struct bkey_s_c k;
+
+	iter = bch2_trans_get_iter(trans, desc.btree_id,
+				   POS(inode, desc.hash_key(info, key)),
+				   BTREE_ITER_SLOTS|BTREE_ITER_INTENT);
+	if (IS_ERR(iter))
+		return iter;
+
+	for_each_btree_key_continue(iter, BTREE_ITER_SLOTS, k) {
+		if (iter->pos.inode != inode)
+			break;
+
+		if (k.k->type != desc.key_type)
+			return iter;
+	}
+
+	return IS_ERR(k.k) ? ERR_CAST(k.k) : ERR_PTR(-ENOSPC);
+}
+
+static 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;
+
+	iter = bch2_trans_copy_iter(trans, start);
+	if (IS_ERR(iter))
+		return PTR_ERR(iter);
+
+	bch2_btree_iter_next_slot(iter);
+
+	for_each_btree_key_continue(iter, BTREE_ITER_SLOTS, k) {
+		if (k.k->type != desc.key_type &&
+		    k.k->type != desc.whiteout_type)
+			return false;
+
+		if (k.k->type == desc.key_type &&
+		    desc.hash_bkey(info, k) <= start->pos.offset)
+			return true;
+	}
+	return btree_iter_err(k);
+}
+
+static inline int __bch2_hash_set(struct btree_trans *trans,
+				  const struct bch_hash_desc desc,
+				  const struct bch_hash_info *info,
+				  u64 inode, struct bkey_i *insert, int flags)
+{
+	struct btree_iter *iter, *slot = NULL;
+	struct bkey_s_c k;
+
+	iter = bch2_trans_get_iter(trans, desc.btree_id,
+			POS(inode, desc.hash_bkey(info, bkey_i_to_s_c(insert))),
+			BTREE_ITER_SLOTS|BTREE_ITER_INTENT);
+	if (IS_ERR(iter))
+		return PTR_ERR(iter);
+
+	for_each_btree_key_continue(iter, BTREE_ITER_SLOTS, k) {
+		if (iter->pos.inode != inode)
+			break;
+
+		if (k.k->type == desc.key_type) {
+			if (!desc.cmp_bkey(k, bkey_i_to_s_c(insert)))
+				goto found;
+
+			/* hash collision: */
+			continue;
+		}
+
+		if (!slot &&
+		    !(flags & BCH_HASH_SET_MUST_REPLACE)) {
+			slot = bch2_trans_copy_iter(trans, iter);
+			if (IS_ERR(slot))
+				return PTR_ERR(slot);
+		}
+
+		if (k.k->type != desc.whiteout_type)
+			goto not_found;
+	}
+
+	return btree_iter_err(k) ?: -ENOSPC;
+not_found:
+	if (flags & BCH_HASH_SET_MUST_REPLACE)
+		return -ENOENT;
+
+	insert->k.p = slot->pos;
+	bch2_trans_update(trans, slot, insert, 0);
+	return 0;
+found:
+	if (flags & BCH_HASH_SET_MUST_CREATE)
+		return -EEXIST;
+
+	insert->k.p = iter->pos;
+	bch2_trans_update(trans, iter, insert, 0);
+	return 0;
+}
+
+static inline int bch2_hash_set(const struct bch_hash_desc desc,
+			       const struct bch_hash_info *info,
+			       struct bch_fs *c, u64 inode,
+			       u64 *journal_seq,
+			       struct bkey_i *insert, int flags)
+{
+	return bch2_trans_do(c, journal_seq, flags|BTREE_INSERT_ATOMIC,
+			__bch2_hash_set(&trans, desc, info,
+					inode, insert, flags));
+}
+
+static 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)
+{
+	struct bkey_i *delete;
+	int ret;
+
+	ret = bch2_hash_needs_whiteout(trans, desc, info, iter);
+	if (ret < 0)
+		return ret;
+
+	delete = bch2_trans_kmalloc(trans, sizeof(*delete));
+	if (IS_ERR(delete))
+		return PTR_ERR(delete);
+
+	bkey_init(&delete->k);
+	delete->k.p = iter->pos;
+	delete->k.type = ret ? desc.whiteout_type : KEY_TYPE_DELETED;
+
+	bch2_trans_update(trans, iter, delete, 0);
+	return 0;
+}
+
+static inline int bch2_hash_delete(struct btree_trans *trans,
+				   const struct bch_hash_desc desc,
+				   const struct bch_hash_info *info,
+				   u64 inode, const void *key)
+{
+	struct btree_iter *iter;
+
+	iter = bch2_hash_lookup(trans, desc, info, inode, key,
+				BTREE_ITER_INTENT);
+	if (IS_ERR(iter))
+		return PTR_ERR(iter);
+
+	return bch2_hash_delete_at(trans, desc, info, iter);
+}
+
+#endif /* _BCACHEFS_STR_HASH_H */