linux-apfs-oot/key.h

/* SPDX-License-Identifier: GPL-2.0 */
/*
 *  linux/fs/apfs/key.h
 *
 * Copyright (C) 2018 Ernesto A. Fernández <ernesto.mnd.fernandez@gmail.com>
 */

#ifndef _APFS_KEY_H
#define _APFS_KEY_H

#include <linux/types.h>

struct super_block;

/*
 * Structure of a key in an object map B-tree
 */
struct apfs_omap_key {
	__le64 ok_oid;
	__le64 ok_xid;
} __packed;

/* Catalog records types */
enum {
	APFS_TYPE_ANY			= 0,
	APFS_TYPE_SNAP_METADATA		= 1,
	APFS_TYPE_EXTENT		= 2,
	APFS_TYPE_INODE			= 3,
	APFS_TYPE_XATTR			= 4,
	APFS_TYPE_SIBLING_LINK		= 5,
	APFS_TYPE_DSTREAM_ID		= 6,
	APFS_TYPE_CRYPTO_STATE		= 7,
	APFS_TYPE_FILE_EXTENT		= 8,
	APFS_TYPE_DIR_REC		= 9,
	APFS_TYPE_DIR_STATS		= 10,
	APFS_TYPE_SNAP_NAME		= 11,
	APFS_TYPE_SIBLING_MAP		= 12,
	APFS_TYPE_MAX_VALID		= 12,
	APFS_TYPE_MAX			= 15,
	APFS_TYPE_INVALID		= 15,
};

/* Bit masks for the 'obj_id_and_type' field of a key header */
#define APFS_OBJ_ID_MASK		0x0fffffffffffffffULL
#define APFS_OBJ_TYPE_MASK		0xf000000000000000ULL
#define APFS_OBJ_TYPE_SHIFT		60

/* Key header for filesystem-object keys */
struct apfs_key_header {
	__le64 obj_id_and_type;
} __packed;

/*
 * Structure of the key for an inode record
 */
struct apfs_inode_key {
	struct apfs_key_header hdr;
} __packed;

/*
 * Structure of the key for a file extent record
 */
struct apfs_file_extent_key {
	struct apfs_key_header hdr;
	__le64 logical_addr;
} __packed;

/*
 * Structure of the key for a data stream record
 */
struct apfs_dstream_id_key {
	struct apfs_key_header hdr;
} __packed;

/* Bit masks for the 'name_len_and_hash' field of a directory entry */
#define APFS_DREC_LEN_MASK	0x000003ff
#define APFS_DREC_HASH_MASK	0xfffffc00
#define APFS_DREC_HASH_SHIFT	10

/* The name length in the catalog key counts the terminating null byte. */
#define APFS_NAME_LEN		(APFS_DREC_LEN_MASK - 1)

/* Bit masks for the 'type' field of a directory entry */
enum {
	APFS_DREC_TYPE_MASK	= 0x000f,
	APFS_DREC_RESERVED_10	= 0x0010
};

/*
 * Structure of the key for a directory entry, including a precomputed
 * hash of its name
 */
struct apfs_drec_hashed_key {
	struct apfs_key_header hdr;
	__le32 name_len_and_hash;
	u8 name[0];
} __packed;

/*
 * Structure of the key for an extended attributes record
 */
struct apfs_xattr_key {
	struct apfs_key_header hdr;
	__le16 name_len;
	u8 name[0];
} __packed;

/*
 * In-memory representation of a key, as relevant for a b-tree query.
 */
struct apfs_key {
	u64		id;
	u64		number;	/* Extent offset, name hash or transaction id */
	const char	*name;	/* On-disk name string */
	u8		type;	/* Record type (0 for the omap) */
};

/**
 * apfs_init_omap_key - Initialize an in-memory key for an omap query
 * @oid:	object id
 * @xid:	latest transaction id
 * @key:	apfs_key structure to initialize
 */
static inline void apfs_init_omap_key(u64 oid, u64 xid, struct apfs_key *key)
{
	key->id = oid;
	key->type = 0;
	key->number = xid;
	key->name = NULL;
}

/**
 * apfs_init_inode_key - Initialize an in-memory key for an inode query
 * @ino:	inode number
 * @key:	apfs_key structure to initialize
 */
static inline void apfs_init_inode_key(u64 ino, struct apfs_key *key)
{
	key->id = ino;
	key->type = APFS_TYPE_INODE;
	key->number = 0;
	key->name = NULL;
}

/**
 * apfs_init_file_extent_key - Initialize an in-memory key for an extent query
 * @id:		extent id
 * @offset:	logical address (0 for a multiple query)
 * @key:	apfs_key structure to initialize
 */
static inline void apfs_init_file_extent_key(u64 id, u64 offset,
					     struct apfs_key *key)
{
	key->id = id;
	key->type = APFS_TYPE_FILE_EXTENT;
	key->number = offset;
	key->name = NULL;
}

extern void apfs_init_drec_hashed_key(struct super_block *sb, u64 ino,
				      const char *name, struct apfs_key *key);

/**
 * apfs_init_xattr_key - Initialize an in-memory key for a xattr query
 * @ino:	inode number of the parent file
 * @name:	xattr name (NULL for a multiple query)
 * @key:	apfs_key structure to initialize
 */
static inline void apfs_init_xattr_key(u64 ino, const char *name,
				       struct apfs_key *key)
{
	key->id = ino;
	key->type = APFS_TYPE_XATTR;
	key->number = 0;
	key->name = name;
}

extern int apfs_filename_cmp(struct super_block *sb,
			     const char *name1, const char *name2);
extern int apfs_keycmp(struct super_block *sb,
		       struct apfs_key *k1, struct apfs_key *k2);
extern int apfs_read_cat_key(void *raw, int size, struct apfs_key *key);
extern int apfs_read_omap_key(void *raw, int size, struct apfs_key *key);

#endif	/* _APFS_KEY_H */