/* SPDX-License-Identifier: GPL-2.0-only */ /* * This file is part of UBIFS. * * Copyright (C) 2006-2008 Nokia Corporation. * * Authors: Artem Bityutskiy (Битюцкий Артём) * Adrian Hunter */ /* * This file describes UBIFS on-flash format and contains definitions of all the * relevant data structures and constants. * * All UBIFS on-flash objects are stored in the form of nodes. All nodes start * with the UBIFS node magic number and have the same common header. Nodes * always sit at 8-byte aligned positions on the media and node header sizes are * also 8-byte aligned (except for the indexing node and the padding node). */ #ifndef __UBIFS_MEDIA_H__ #define __UBIFS_MEDIA_H__ /* UBIFS node magic number (must not have the padding byte first or last) */ #define UBIFS_NODE_MAGIC … /* * UBIFS on-flash format version. This version is increased when the on-flash * format is changing. If this happens, UBIFS is will support older versions as * well. But older UBIFS code will not support newer formats. Format changes * will be rare and only when absolutely necessary, e.g. to fix a bug or to add * a new feature. * * UBIFS went into mainline kernel with format version 4. The older formats * were development formats. */ #define UBIFS_FORMAT_VERSION … /* * Read-only compatibility version. If the UBIFS format is changed, older UBIFS * implementations will not be able to mount newer formats in read-write mode. * However, depending on the change, it may be possible to mount newer formats * in R/O mode. This is indicated by the R/O compatibility version which is * stored in the super-block. * * This is needed to support boot-loaders which only need R/O mounting. With * this flag it is possible to do UBIFS format changes without a need to update * boot-loaders. */ #define UBIFS_RO_COMPAT_VERSION … /* Minimum logical eraseblock size in bytes */ #define UBIFS_MIN_LEB_SZ … /* Initial CRC32 value used when calculating CRC checksums */ #define UBIFS_CRC32_INIT … /* * UBIFS does not try to compress data if its length is less than the below * constant. */ #define UBIFS_MIN_COMPR_LEN … /* * If compressed data length is less than %UBIFS_MIN_COMPRESS_DIFF bytes * shorter than uncompressed data length, UBIFS prefers to leave this data * node uncompress, because it'll be read faster. */ #define UBIFS_MIN_COMPRESS_DIFF … /* Root inode number */ #define UBIFS_ROOT_INO … /* Lowest inode number used for regular inodes (not UBIFS-only internal ones) */ #define UBIFS_FIRST_INO … /* * Maximum file name and extended attribute length (must be a multiple of 8, * minus 1). */ #define UBIFS_MAX_NLEN … /* Maximum number of data journal heads */ #define UBIFS_MAX_JHEADS … /* * Size of UBIFS data block. Note, UBIFS is not a block oriented file-system, * which means that it does not treat the underlying media as consisting of * blocks like in case of hard drives. Do not be confused. UBIFS block is just * the maximum amount of data which one data node can have or which can be * attached to an inode node. */ #define UBIFS_BLOCK_SIZE … #define UBIFS_BLOCK_SHIFT … /* UBIFS padding byte pattern (must not be first or last byte of node magic) */ #define UBIFS_PADDING_BYTE … /* Maximum possible key length */ #define UBIFS_MAX_KEY_LEN … /* Key length ("simple" format) */ #define UBIFS_SK_LEN … /* Minimum index tree fanout */ #define UBIFS_MIN_FANOUT … /* Maximum number of levels in UBIFS indexing B-tree */ #define UBIFS_MAX_LEVELS … /* Maximum amount of data attached to an inode in bytes */ #define UBIFS_MAX_INO_DATA … /* LEB Properties Tree fanout (must be power of 2) and fanout shift */ #define UBIFS_LPT_FANOUT … #define UBIFS_LPT_FANOUT_SHIFT … /* LEB Properties Tree bit field sizes */ #define UBIFS_LPT_CRC_BITS … #define UBIFS_LPT_CRC_BYTES … #define UBIFS_LPT_TYPE_BITS … /* The key is always at the same position in all keyed nodes */ #define UBIFS_KEY_OFFSET … /* Garbage collector journal head number */ #define UBIFS_GC_HEAD … /* Base journal head number */ #define UBIFS_BASE_HEAD … /* Data journal head number */ #define UBIFS_DATA_HEAD … /* * LEB Properties Tree node types. * * UBIFS_LPT_PNODE: LPT leaf node (contains LEB properties) * UBIFS_LPT_NNODE: LPT internal node * UBIFS_LPT_LTAB: LPT's own lprops table * UBIFS_LPT_LSAVE: LPT's save table (big model only) * UBIFS_LPT_NODE_CNT: count of LPT node types * UBIFS_LPT_NOT_A_NODE: all ones (15 for 4 bits) is never a valid node type */ enum { … }; /* * UBIFS inode types. * * UBIFS_ITYPE_REG: regular file * UBIFS_ITYPE_DIR: directory * UBIFS_ITYPE_LNK: soft link * UBIFS_ITYPE_BLK: block device node * UBIFS_ITYPE_CHR: character device node * UBIFS_ITYPE_FIFO: fifo * UBIFS_ITYPE_SOCK: socket * UBIFS_ITYPES_CNT: count of supported file types */ enum { … }; /* * Supported key hash functions. * * UBIFS_KEY_HASH_R5: R5 hash * UBIFS_KEY_HASH_TEST: test hash which just returns first 4 bytes of the name */ enum { … }; /* * Supported key formats. * * UBIFS_SIMPLE_KEY_FMT: simple key format */ enum { … }; /* * The simple key format uses 29 bits for storing UBIFS block number and hash * value. */ #define UBIFS_S_KEY_BLOCK_BITS … #define UBIFS_S_KEY_BLOCK_MASK … #define UBIFS_S_KEY_HASH_BITS … #define UBIFS_S_KEY_HASH_MASK … /* * Key types. * * UBIFS_INO_KEY: inode node key * UBIFS_DATA_KEY: data node key * UBIFS_DENT_KEY: directory entry node key * UBIFS_XENT_KEY: extended attribute entry key * UBIFS_KEY_TYPES_CNT: number of supported key types */ enum { … }; /* Count of LEBs reserved for the superblock area */ #define UBIFS_SB_LEBS … /* Count of LEBs reserved for the master area */ #define UBIFS_MST_LEBS … /* First LEB of the superblock area */ #define UBIFS_SB_LNUM … /* First LEB of the master area */ #define UBIFS_MST_LNUM … /* First LEB of the log area */ #define UBIFS_LOG_LNUM … /* * The below constants define the absolute minimum values for various UBIFS * media areas. Many of them actually depend of flash geometry and the FS * configuration (number of journal heads, orphan LEBs, etc). This means that * the smallest volume size which can be used for UBIFS cannot be pre-defined * by these constants. The file-system that meets the below limitation will not * necessarily mount. UBIFS does run-time calculations and validates the FS * size. */ /* Minimum number of logical eraseblocks in the log */ #define UBIFS_MIN_LOG_LEBS … /* Minimum number of bud logical eraseblocks (one for each head) */ #define UBIFS_MIN_BUD_LEBS … /* Minimum number of journal logical eraseblocks */ #define UBIFS_MIN_JNL_LEBS … /* Minimum number of LPT area logical eraseblocks */ #define UBIFS_MIN_LPT_LEBS … /* Minimum number of orphan area logical eraseblocks */ #define UBIFS_MIN_ORPH_LEBS … /* * Minimum number of main area logical eraseblocks (buds, 3 for the index, 1 * for GC, 1 for deletions, and at least 1 for committed data). */ #define UBIFS_MIN_MAIN_LEBS … /* Minimum number of logical eraseblocks */ #define UBIFS_MIN_LEB_CNT … /* Node sizes (N.B. these are guaranteed to be multiples of 8) */ #define UBIFS_CH_SZ … #define UBIFS_INO_NODE_SZ … #define UBIFS_DATA_NODE_SZ … #define UBIFS_DENT_NODE_SZ … #define UBIFS_TRUN_NODE_SZ … #define UBIFS_PAD_NODE_SZ … #define UBIFS_SB_NODE_SZ … #define UBIFS_MST_NODE_SZ … #define UBIFS_REF_NODE_SZ … #define UBIFS_IDX_NODE_SZ … #define UBIFS_CS_NODE_SZ … #define UBIFS_ORPH_NODE_SZ … #define UBIFS_AUTH_NODE_SZ … #define UBIFS_SIG_NODE_SZ … /* Extended attribute entry nodes are identical to directory entry nodes */ #define UBIFS_XENT_NODE_SZ … /* Only this does not have to be multiple of 8 bytes */ #define UBIFS_BRANCH_SZ … /* Maximum node sizes (N.B. these are guaranteed to be multiples of 8) */ #define UBIFS_MAX_DATA_NODE_SZ … #define UBIFS_MAX_INO_NODE_SZ … #define UBIFS_MAX_DENT_NODE_SZ … #define UBIFS_MAX_XENT_NODE_SZ … /* The largest UBIFS node */ #define UBIFS_MAX_NODE_SZ … /* The maxmimum size of a hash, enough for sha512 */ #define UBIFS_MAX_HASH_LEN … /* The maxmimum size of a hmac, enough for hmac(sha512) */ #define UBIFS_MAX_HMAC_LEN … /* * xattr name of UBIFS encryption context, we don't use a prefix * nor a long name to not waste space on the flash. */ #define UBIFS_XATTR_NAME_ENCRYPTION_CONTEXT … /* Type field in ubifs_sig_node */ #define UBIFS_SIGNATURE_TYPE_PKCS7 … /* * On-flash inode flags. * * UBIFS_COMPR_FL: use compression for this inode * UBIFS_SYNC_FL: I/O on this inode has to be synchronous * UBIFS_IMMUTABLE_FL: inode is immutable * UBIFS_APPEND_FL: writes to the inode may only append data * UBIFS_DIRSYNC_FL: I/O on this directory inode has to be synchronous * UBIFS_XATTR_FL: this inode is the inode for an extended attribute value * UBIFS_CRYPT_FL: use encryption for this inode * * Note, these are on-flash flags which correspond to ioctl flags * (@FS_COMPR_FL, etc). They have the same values now, but generally, do not * have to be the same. */ enum { … }; /* Inode flag bits used by UBIFS */ #define UBIFS_FL_MASK … /* * UBIFS compression algorithms. * * UBIFS_COMPR_NONE: no compression * UBIFS_COMPR_LZO: LZO compression * UBIFS_COMPR_ZLIB: ZLIB compression * UBIFS_COMPR_ZSTD: ZSTD compression * UBIFS_COMPR_TYPES_CNT: count of supported compression types */ enum { … }; /* * UBIFS node types. * * UBIFS_INO_NODE: inode node * UBIFS_DATA_NODE: data node * UBIFS_DENT_NODE: directory entry node * UBIFS_XENT_NODE: extended attribute node * UBIFS_TRUN_NODE: truncation node * UBIFS_PAD_NODE: padding node * UBIFS_SB_NODE: superblock node * UBIFS_MST_NODE: master node * UBIFS_REF_NODE: LEB reference node * UBIFS_IDX_NODE: index node * UBIFS_CS_NODE: commit start node * UBIFS_ORPH_NODE: orphan node * UBIFS_AUTH_NODE: authentication node * UBIFS_SIG_NODE: signature node * UBIFS_NODE_TYPES_CNT: count of supported node types * * Note, we index arrays by these numbers, so keep them low and contiguous. * Node type constants for inodes, direntries and so on have to be the same as * corresponding key type constants. */ enum { … }; /* * Master node flags. * * UBIFS_MST_DIRTY: rebooted uncleanly - master node is dirty * UBIFS_MST_NO_ORPHS: no orphan inodes present * UBIFS_MST_RCVRY: written by recovery */ enum { … }; /* * Node group type (used by recovery to recover whole group or none). * * UBIFS_NO_NODE_GROUP: this node is not part of a group * UBIFS_IN_NODE_GROUP: this node is a part of a group * UBIFS_LAST_OF_NODE_GROUP: this node is the last in a group */ enum { … }; /* * Superblock flags. * * UBIFS_FLG_BIGLPT: if "big" LPT model is used if set * UBIFS_FLG_SPACE_FIXUP: first-mount "fixup" of free space within LEBs needed * UBIFS_FLG_DOUBLE_HASH: store a 32bit cookie in directory entry nodes to * support 64bit cookies for lookups by hash * UBIFS_FLG_ENCRYPTION: this filesystem contains encrypted files * UBIFS_FLG_AUTHENTICATION: this filesystem contains hashes for authentication */ enum { … }; #define UBIFS_FLG_MASK … /** * struct ubifs_ch - common header node. * @magic: UBIFS node magic number (%UBIFS_NODE_MAGIC) * @crc: CRC-32 checksum of the node header * @sqnum: sequence number * @len: full node length * @node_type: node type * @group_type: node group type * @padding: reserved for future, zeroes * * Every UBIFS node starts with this common part. If the node has a key, the * key always goes next. */ struct ubifs_ch { … } __packed; /** * union ubifs_dev_desc - device node descriptor. * @new: new type device descriptor * @huge: huge type device descriptor * * This data structure describes major/minor numbers of a device node. In an * inode is a device node then its data contains an object of this type. UBIFS * uses standard Linux "new" and "huge" device node encodings. */ ubifs_dev_desc __packed; /** * struct ubifs_ino_node - inode node. * @ch: common header * @key: node key * @creat_sqnum: sequence number at time of creation * @size: inode size in bytes (amount of uncompressed data) * @atime_sec: access time seconds * @ctime_sec: creation time seconds * @mtime_sec: modification time seconds * @atime_nsec: access time nanoseconds * @ctime_nsec: creation time nanoseconds * @mtime_nsec: modification time nanoseconds * @nlink: number of hard links * @uid: owner ID * @gid: group ID * @mode: access flags * @flags: per-inode flags (%UBIFS_COMPR_FL, %UBIFS_SYNC_FL, etc) * @data_len: inode data length * @xattr_cnt: count of extended attributes this inode has * @xattr_size: summarized size of all extended attributes in bytes * @padding1: reserved for future, zeroes * @xattr_names: sum of lengths of all extended attribute names belonging to * this inode * @compr_type: compression type used for this inode * @padding2: reserved for future, zeroes * @data: data attached to the inode * * Note, even though inode compression type is defined by @compr_type, some * nodes of this inode may be compressed with different compressor - this * happens if compression type is changed while the inode already has data * nodes. But @compr_type will be use for further writes to the inode. * * Note, do not forget to amend 'zero_ino_node_unused()' function when changing * the padding fields. */ struct ubifs_ino_node { … } __packed; /** * struct ubifs_dent_node - directory entry node. * @ch: common header * @key: node key * @inum: target inode number * @padding1: reserved for future, zeroes * @type: type of the target inode (%UBIFS_ITYPE_REG, %UBIFS_ITYPE_DIR, etc) * @nlen: name length * @cookie: A 32bits random number, used to construct a 64bits * identifier. * @name: zero-terminated name * * Note, do not forget to amend 'zero_dent_node_unused()' function when * changing the padding fields. */ struct ubifs_dent_node { … } __packed; /** * struct ubifs_data_node - data node. * @ch: common header * @key: node key * @size: uncompressed data size in bytes * @compr_type: compression type (%UBIFS_COMPR_NONE, %UBIFS_COMPR_LZO, etc) * @compr_size: compressed data size in bytes, only valid when data is encrypted * @data: data * */ struct ubifs_data_node { … } __packed; /** * struct ubifs_trun_node - truncation node. * @ch: common header * @inum: truncated inode number * @padding: reserved for future, zeroes * @old_size: size before truncation * @new_size: size after truncation * * This node exists only in the journal and never goes to the main area. Note, * do not forget to amend 'zero_trun_node_unused()' function when changing the * padding fields. */ struct ubifs_trun_node { … } __packed; /** * struct ubifs_pad_node - padding node. * @ch: common header * @pad_len: how many bytes after this node are unused (because padded) * @padding: reserved for future, zeroes */ struct ubifs_pad_node { … } __packed; /** * struct ubifs_sb_node - superblock node. * @ch: common header * @padding: reserved for future, zeroes * @key_hash: type of hash function used in keys * @key_fmt: format of the key * @flags: file-system flags (%UBIFS_FLG_BIGLPT, etc) * @min_io_size: minimal input/output unit size * @leb_size: logical eraseblock size in bytes * @leb_cnt: count of LEBs used by file-system * @max_leb_cnt: maximum count of LEBs used by file-system * @max_bud_bytes: maximum amount of data stored in buds * @log_lebs: log size in logical eraseblocks * @lpt_lebs: number of LEBs used for lprops table * @orph_lebs: number of LEBs used for recording orphans * @jhead_cnt: count of journal heads * @fanout: tree fanout (max. number of links per indexing node) * @lsave_cnt: number of LEB numbers in LPT's save table * @fmt_version: UBIFS on-flash format version * @default_compr: default compression algorithm (%UBIFS_COMPR_LZO, etc) * @padding1: reserved for future, zeroes * @rp_uid: reserve pool UID * @rp_gid: reserve pool GID * @rp_size: size of the reserved pool in bytes * @padding2: reserved for future, zeroes * @time_gran: time granularity in nanoseconds * @uuid: UUID generated when the file system image was created * @ro_compat_version: UBIFS R/O compatibility version * @hmac: HMAC to authenticate the superblock node * @hmac_wkm: HMAC of a well known message (the string "UBIFS") as a convenience * to the user to check if the correct key is passed. * @hash_algo: The hash algo used for this filesystem (one of enum hash_algo) * @hash_mst: hash of the master node, only valid for signed images in which the * master node does not contain a hmac */ struct ubifs_sb_node { … } __packed; /** * struct ubifs_mst_node - master node. * @ch: common header * @highest_inum: highest inode number in the committed index * @cmt_no: commit number * @flags: various flags (%UBIFS_MST_DIRTY, etc) * @log_lnum: start of the log * @root_lnum: LEB number of the root indexing node * @root_offs: offset within @root_lnum * @root_len: root indexing node length * @gc_lnum: LEB reserved for garbage collection (%-1 value means the LEB was * not reserved and should be reserved on mount) * @ihead_lnum: LEB number of index head * @ihead_offs: offset of index head * @index_size: size of index on flash * @total_free: total free space in bytes * @total_dirty: total dirty space in bytes * @total_used: total used space in bytes (includes only data LEBs) * @total_dead: total dead space in bytes (includes only data LEBs) * @total_dark: total dark space in bytes (includes only data LEBs) * @lpt_lnum: LEB number of LPT root nnode * @lpt_offs: offset of LPT root nnode * @nhead_lnum: LEB number of LPT head * @nhead_offs: offset of LPT head * @ltab_lnum: LEB number of LPT's own lprops table * @ltab_offs: offset of LPT's own lprops table * @lsave_lnum: LEB number of LPT's save table (big model only) * @lsave_offs: offset of LPT's save table (big model only) * @lscan_lnum: LEB number of last LPT scan * @empty_lebs: number of empty logical eraseblocks * @idx_lebs: number of indexing logical eraseblocks * @leb_cnt: count of LEBs used by file-system * @hash_root_idx: the hash of the root index node * @hash_lpt: the hash of the LPT * @hmac: HMAC to authenticate the master node * @padding: reserved for future, zeroes */ struct ubifs_mst_node { … } __packed; /** * struct ubifs_ref_node - logical eraseblock reference node. * @ch: common header * @lnum: the referred logical eraseblock number * @offs: start offset in the referred LEB * @jhead: journal head number * @padding: reserved for future, zeroes */ struct ubifs_ref_node { … } __packed; /** * struct ubifs_auth_node - node for authenticating other nodes * @ch: common header * @hmac: The HMAC */ struct ubifs_auth_node { … } __packed; /** * struct ubifs_sig_node - node for signing other nodes * @ch: common header * @type: type of the signature, currently only UBIFS_SIGNATURE_TYPE_PKCS7 * supported * @len: The length of the signature data * @padding: reserved for future, zeroes * @sig: The signature data */ struct ubifs_sig_node { … } __packed; /** * struct ubifs_branch - key/reference/length branch * @lnum: LEB number of the target node * @offs: offset within @lnum * @len: target node length * @key: key * * In an authenticated UBIFS we have the hash of the referenced node after @key. * This can't be added to the struct type definition because @key is a * dynamically sized element already. */ struct ubifs_branch { … } __packed; /** * struct ubifs_idx_node - indexing node. * @ch: common header * @child_cnt: number of child index nodes * @level: tree level * @branches: LEB number / offset / length / key branches */ struct ubifs_idx_node { … } __packed; /** * struct ubifs_cs_node - commit start node. * @ch: common header * @cmt_no: commit number */ struct ubifs_cs_node { … } __packed; /** * struct ubifs_orph_node - orphan node. * @ch: common header * @cmt_no: commit number (also top bit is set on the last node of the commit) * @inos: inode numbers of orphans */ struct ubifs_orph_node { … } __packed; #endif /* __UBIFS_MEDIA_H__ */
Codebase Browser
linux