fs/ubifs/ubifs-media.h

   1 /*
   2  * This file is part of UBIFS.
   3  *
   4  * Copyright (C) 2006-2008 Nokia Corporation.
   5  *
   6  * This program is free software; you can redistribute it and/or modify it
   7  * under the terms of the GNU General Public License version 2 as published by
   8  * the Free Software Foundation.
   9  *
  10  * This program is distributed in the hope that it will be useful, but WITHOUT
  11  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  12  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  13  * more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along with
  16  * this program; if not, write to the Free Software Foundation, Inc., 51
  17  * Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
  18  *
  19  * Authors: Artem Bityutskiy (Битюцкий Артём)
  20  *          Adrian Hunter
  21  */
  22
  23 /*
  24  * This file describes UBIFS on-flash format and contains definitions of all the
  25  * relevant data structures and constants.
  26  *
  27  * All UBIFS on-flash objects are stored in the form of nodes. All nodes start
  28  * with the UBIFS node magic number and have the same common header. Nodes
  29  * always sit at 8-byte aligned positions on the media and node header sizes are
  30  * also 8-byte aligned (except for the indexing node and the padding node).
  31  */
  32
  33 #ifndef __UBIFS_MEDIA_H__
  34 #define __UBIFS_MEDIA_H__
  35
  36 /* UBIFS node magic number (must not have the padding byte first or last) */
  37 #define UBIFS_NODE_MAGIC  0x06101831
  38
  39 /*
  40  * UBIFS on-flash format version. This version is increased when the on-flash
  41  * format is changing. If this happens, UBIFS is will support older versions as
  42  * well. But older UBIFS code will not support newer formats. Format changes
  43  * will be rare and only when absolutely necessary, e.g. to fix a bug or to add
  44  * a new feature.
  45  *
  46  * UBIFS went into mainline kernel with format version 4. The older formats
  47  * were development formats.
  48  */
  49 #define UBIFS_FORMAT_VERSION 4
  50
  51 /*
  52  * Read-only compatibility version. If the UBIFS format is changed, older UBIFS
  53  * implementations will not be able to mount newer formats in read-write mode.
  54  * However, depending on the change, it may be possible to mount newer formats
  55  * in R/O mode. This is indicated by the R/O compatibility version which is
  56  * stored in the super-block.
  57  *
  58  * This is needed to support boot-loaders which only need R/O mounting. With
  59  * this flag it is possible to do UBIFS format changes without a need to update
  60  * boot-loaders.
  61  */
  62 #define UBIFS_RO_COMPAT_VERSION 0
  63
  64 /* Minimum logical eraseblock size in bytes */
  65 #define UBIFS_MIN_LEB_SZ (15*1024)
  66
  67 /* Initial CRC32 value used when calculating CRC checksums */
  68 #define UBIFS_CRC32_INIT 0xFFFFFFFFU
  69
  70 /*
  71  * UBIFS does not try to compress data if its length is less than the below
  72  * constant.
  73  */
  74 #define UBIFS_MIN_COMPR_LEN 128
  75
  76 /*
  77  * If compressed data length is less than %UBIFS_MIN_COMPRESS_DIFF bytes
  78  * shorter than uncompressed data length, UBIFS prefers to leave this data
  79  * node uncompress, because it'll be read faster.
  80  */
  81 #define UBIFS_MIN_COMPRESS_DIFF 64
  82
  83 /* Root inode number */
  84 #define UBIFS_ROOT_INO 1
  85
  86 /* Lowest inode number used for regular inodes (not UBIFS-only internal ones) */
  87 #define UBIFS_FIRST_INO 64
  88
  89 /*
  90  * Maximum file name and extended attribute length (must be a multiple of 8,
  91  * minus 1).
  92  */
  93 #define UBIFS_MAX_NLEN 255
  94
  95 /* Maximum number of data journal heads */
  96 #define UBIFS_MAX_JHEADS 1
  97
  98 /*
  99  * Size of UBIFS data block. Note, UBIFS is not a block oriented file-system,
 100  * which means that it does not treat the underlying media as consisting of
 101  * blocks like in case of hard drives. Do not be confused. UBIFS block is just
 102  * the maximum amount of data which one data node can have or which can be
 103  * attached to an inode node.
 104  */
 105 #define UBIFS_BLOCK_SIZE  4096
 106 #define UBIFS_BLOCK_SHIFT 12
 107
 108 /* UBIFS padding byte pattern (must not be first or last byte of node magic) */
 109 #define UBIFS_PADDING_BYTE 0xCE
 110
 111 /* Maximum possible key length */
 112 #define UBIFS_MAX_KEY_LEN 16
 113
 114 /* Key length ("simple" format) */
 115 #define UBIFS_SK_LEN 8
 116
 117 /* Minimum index tree fanout */
 118 #define UBIFS_MIN_FANOUT 3
 119
 120 /* Maximum number of levels in UBIFS indexing B-tree */
 121 #define UBIFS_MAX_LEVELS 512
 122
 123 /* Maximum amount of data attached to an inode in bytes */
 124 #define UBIFS_MAX_INO_DATA UBIFS_BLOCK_SIZE
 125
 126 /* LEB Properties Tree fanout (must be power of 2) and fanout shift */
 127 #define UBIFS_LPT_FANOUT 4
 128 #define UBIFS_LPT_FANOUT_SHIFT 2
 129
 130 /* LEB Properties Tree bit field sizes */
 131 #define UBIFS_LPT_CRC_BITS 16
 132 #define UBIFS_LPT_CRC_BYTES 2
 133 #define UBIFS_LPT_TYPE_BITS 4
 134
 135 /* The key is always at the same position in all keyed nodes */
 136 #define UBIFS_KEY_OFFSET offsetof(struct ubifs_ino_node, key)
 137
 138 /* Garbage collector journal head number */
 139 #define UBIFS_GC_HEAD   0
 140 /* Base journal head number */
 141 #define UBIFS_BASE_HEAD 1
 142 /* Data journal head number */
 143 #define UBIFS_DATA_HEAD 2
 144
 145 /*
 146  * LEB Properties Tree node types.
 147  *
 148  * UBIFS_LPT_PNODE: LPT leaf node (contains LEB properties)
 149  * UBIFS_LPT_NNODE: LPT internal node
 150  * UBIFS_LPT_LTAB: LPT's own lprops table
 151  * UBIFS_LPT_LSAVE: LPT's save table (big model only)
 152  * UBIFS_LPT_NODE_CNT: count of LPT node types
 153  * UBIFS_LPT_NOT_A_NODE: all ones (15 for 4 bits) is never a valid node type
 154  */
 155 enum {
 156         UBIFS_LPT_PNODE,
 157         UBIFS_LPT_NNODE,
 158         UBIFS_LPT_LTAB,
 159         UBIFS_LPT_LSAVE,
 160         UBIFS_LPT_NODE_CNT,
 161         UBIFS_LPT_NOT_A_NODE = (1 << UBIFS_LPT_TYPE_BITS) - 1,
 162 };
 163
 164 /*
 165  * UBIFS inode types.
 166  *
 167  * UBIFS_ITYPE_REG: regular file
 168  * UBIFS_ITYPE_DIR: directory
 169  * UBIFS_ITYPE_LNK: soft link
 170  * UBIFS_ITYPE_BLK: block device node
 171  * UBIFS_ITYPE_CHR: character device node
 172  * UBIFS_ITYPE_FIFO: fifo
 173  * UBIFS_ITYPE_SOCK: socket
 174  * UBIFS_ITYPES_CNT: count of supported file types
 175  */
 176 enum {
 177         UBIFS_ITYPE_REG,
 178         UBIFS_ITYPE_DIR,
 179         UBIFS_ITYPE_LNK,
 180         UBIFS_ITYPE_BLK,
 181         UBIFS_ITYPE_CHR,
 182         UBIFS_ITYPE_FIFO,
 183         UBIFS_ITYPE_SOCK,
 184         UBIFS_ITYPES_CNT,
 185 };
 186
 187 /*
 188  * Supported key hash functions.
 189  *
 190  * UBIFS_KEY_HASH_R5: R5 hash
 191  * UBIFS_KEY_HASH_TEST: test hash which just returns first 4 bytes of the name
 192  */
 193 enum {
 194         UBIFS_KEY_HASH_R5,
 195         UBIFS_KEY_HASH_TEST,
 196 };
 197
 198 /*
 199  * Supported key formats.
 200  *
 201  * UBIFS_SIMPLE_KEY_FMT: simple key format
 202  */
 203 enum {
 204         UBIFS_SIMPLE_KEY_FMT,
 205 };
 206
 207 /*
 208  * The simple key format uses 29 bits for storing UBIFS block number and hash
 209  * value.
 210  */
 211 #define UBIFS_S_KEY_BLOCK_BITS 29
 212 #define UBIFS_S_KEY_BLOCK_MASK 0x1FFFFFFF
 213 #define UBIFS_S_KEY_HASH_BITS  UBIFS_S_KEY_BLOCK_BITS
 214 #define UBIFS_S_KEY_HASH_MASK  UBIFS_S_KEY_BLOCK_MASK
 215
 216 /*
 217  * Key types.
 218  *
 219  * UBIFS_INO_KEY: inode node key
 220  * UBIFS_DATA_KEY: data node key
 221  * UBIFS_DENT_KEY: directory entry node key
 222  * UBIFS_XENT_KEY: extended attribute entry key
 223  * UBIFS_KEY_TYPES_CNT: number of supported key types
 224  */
 225 enum {
 226         UBIFS_INO_KEY,
 227         UBIFS_DATA_KEY,
 228         UBIFS_DENT_KEY,
 229         UBIFS_XENT_KEY,
 230         UBIFS_KEY_TYPES_CNT,
 231 };
 232
 233 /* Count of LEBs reserved for the superblock area */
 234 #define UBIFS_SB_LEBS 1
 235 /* Count of LEBs reserved for the master area */
 236 #define UBIFS_MST_LEBS 2
 237
 238 /* First LEB of the superblock area */
 239 #define UBIFS_SB_LNUM 0
 240 /* First LEB of the master area */
 241 #define UBIFS_MST_LNUM (UBIFS_SB_LNUM + UBIFS_SB_LEBS)
 242 /* First LEB of the log area */
 243 #define UBIFS_LOG_LNUM (UBIFS_MST_LNUM + UBIFS_MST_LEBS)
 244
 245 /*
 246  * The below constants define the absolute minimum values for various UBIFS
 247  * media areas. Many of them actually depend of flash geometry and the FS
 248  * configuration (number of journal heads, orphan LEBs, etc). This means that
 249  * the smallest volume size which can be used for UBIFS cannot be pre-defined
 250  * by these constants. The file-system that meets the below limitation will not
 251  * necessarily mount. UBIFS does run-time calculations and validates the FS
 252  * size.
 253  */
 254
 255 /* Minimum number of logical eraseblocks in the log */
 256 #define UBIFS_MIN_LOG_LEBS 2
 257 /* Minimum number of bud logical eraseblocks (one for each head) */
 258 #define UBIFS_MIN_BUD_LEBS 3
 259 /* Minimum number of journal logical eraseblocks */
 260 #define UBIFS_MIN_JNL_LEBS (UBIFS_MIN_LOG_LEBS + UBIFS_MIN_BUD_LEBS)
 261 /* Minimum number of LPT area logical eraseblocks */
 262 #define UBIFS_MIN_LPT_LEBS 2
 263 /* Minimum number of orphan area logical eraseblocks */
 264 #define UBIFS_MIN_ORPH_LEBS 1
 265 /*
 266  * Minimum number of main area logical eraseblocks (buds, 3 for the index, 1
 267  * for GC, 1 for deletions, and at least 1 for committed data).
 268  */
 269 #define UBIFS_MIN_MAIN_LEBS (UBIFS_MIN_BUD_LEBS + 6)
 270
 271 /* Minimum number of logical eraseblocks */
 272 #define UBIFS_MIN_LEB_CNT (UBIFS_SB_LEBS + UBIFS_MST_LEBS + \
 273                            UBIFS_MIN_LOG_LEBS + UBIFS_MIN_LPT_LEBS + \
 274                            UBIFS_MIN_ORPH_LEBS + UBIFS_MIN_MAIN_LEBS)
 275
 276 /* Node sizes (N.B. these are guaranteed to be multiples of 8) */
 277 #define UBIFS_CH_SZ        sizeof(struct ubifs_ch)
 278 #define UBIFS_INO_NODE_SZ  sizeof(struct ubifs_ino_node)
 279 #define UBIFS_DATA_NODE_SZ sizeof(struct ubifs_data_node)
 280 #define UBIFS_DENT_NODE_SZ sizeof(struct ubifs_dent_node)
 281 #define UBIFS_TRUN_NODE_SZ sizeof(struct ubifs_trun_node)
 282 #define UBIFS_PAD_NODE_SZ  sizeof(struct ubifs_pad_node)
 283 #define UBIFS_SB_NODE_SZ   sizeof(struct ubifs_sb_node)
 284 #define UBIFS_MST_NODE_SZ  sizeof(struct ubifs_mst_node)
 285 #define UBIFS_REF_NODE_SZ  sizeof(struct ubifs_ref_node)
 286 #define UBIFS_IDX_NODE_SZ  sizeof(struct ubifs_idx_node)
 287 #define UBIFS_CS_NODE_SZ   sizeof(struct ubifs_cs_node)
 288 #define UBIFS_ORPH_NODE_SZ sizeof(struct ubifs_orph_node)
 289 /* Extended attribute entry nodes are identical to directory entry nodes */
 290 #define UBIFS_XENT_NODE_SZ UBIFS_DENT_NODE_SZ
 291 /* Only this does not have to be multiple of 8 bytes */
 292 #define UBIFS_BRANCH_SZ    sizeof(struct ubifs_branch)
 293
 294 /* Maximum node sizes (N.B. these are guaranteed to be multiples of 8) */
 295 #define UBIFS_MAX_DATA_NODE_SZ  (UBIFS_DATA_NODE_SZ + UBIFS_BLOCK_SIZE)
 296 #define UBIFS_MAX_INO_NODE_SZ   (UBIFS_INO_NODE_SZ + UBIFS_MAX_INO_DATA)
 297 #define UBIFS_MAX_DENT_NODE_SZ  (UBIFS_DENT_NODE_SZ + UBIFS_MAX_NLEN + 1)
 298 #define UBIFS_MAX_XENT_NODE_SZ  UBIFS_MAX_DENT_NODE_SZ
 299
 300 /* The largest UBIFS node */
 301 #define UBIFS_MAX_NODE_SZ UBIFS_MAX_INO_NODE_SZ
 302
 303 /*
 304  * On-flash inode flags.
 305  *
 306  * UBIFS_COMPR_FL: use compression for this inode
 307  * UBIFS_SYNC_FL:  I/O on this inode has to be synchronous
 308  * UBIFS_IMMUTABLE_FL: inode is immutable
 309  * UBIFS_APPEND_FL: writes to the inode may only append data
 310  * UBIFS_DIRSYNC_FL: I/O on this directory inode has to be synchronous
 311  * UBIFS_XATTR_FL: this inode is the inode for an extended attribute value
 312  *
 313  * Note, these are on-flash flags which correspond to ioctl flags
 314  * (@FS_COMPR_FL, etc). They have the same values now, but generally, do not
 315  * have to be the same.
 316  */
 317 enum {
 318         UBIFS_COMPR_FL     = 0x01,
 319         UBIFS_SYNC_FL      = 0x02,
 320         UBIFS_IMMUTABLE_FL = 0x04,
 321         UBIFS_APPEND_FL    = 0x08,
 322         UBIFS_DIRSYNC_FL   = 0x10,
 323         UBIFS_XATTR_FL     = 0x20,
 324 };
 325
 326 /* Inode flag bits used by UBIFS */
 327 #define UBIFS_FL_MASK 0x0000001F
 328
 329 /*
 330  * UBIFS compression algorithms.
 331  *
 332  * UBIFS_COMPR_NONE: no compression
 333  * UBIFS_COMPR_LZO: LZO compression
 334  * UBIFS_COMPR_ZLIB: ZLIB compression
 335  * UBIFS_COMPR_TYPES_CNT: count of supported compression types
 336  */
 337 enum {
 338         UBIFS_COMPR_NONE,
 339         UBIFS_COMPR_LZO,
 340         UBIFS_COMPR_ZLIB,
 341         UBIFS_COMPR_TYPES_CNT,
 342 };
 343
 344 /*
 345  * UBIFS node types.
 346  *
 347  * UBIFS_INO_NODE: inode node
 348  * UBIFS_DATA_NODE: data node
 349  * UBIFS_DENT_NODE: directory entry node
 350  * UBIFS_XENT_NODE: extended attribute node
 351  * UBIFS_TRUN_NODE: truncation node
 352  * UBIFS_PAD_NODE: padding node
 353  * UBIFS_SB_NODE: superblock node
 354  * UBIFS_MST_NODE: master node
 355  * UBIFS_REF_NODE: LEB reference node
 356  * UBIFS_IDX_NODE: index node
 357  * UBIFS_CS_NODE: commit start node
 358  * UBIFS_ORPH_NODE: orphan node
 359  * UBIFS_NODE_TYPES_CNT: count of supported node types
 360  *
 361  * Note, we index arrays by these numbers, so keep them low and contiguous.
 362  * Node type constants for inodes, direntries and so on have to be the same as
 363  * corresponding key type constants.
 364  */
 365 enum {
 366         UBIFS_INO_NODE,
 367         UBIFS_DATA_NODE,
 368         UBIFS_DENT_NODE,
 369         UBIFS_XENT_NODE,
 370         UBIFS_TRUN_NODE,
 371         UBIFS_PAD_NODE,
 372         UBIFS_SB_NODE,
 373         UBIFS_MST_NODE,
 374         UBIFS_REF_NODE,
 375         UBIFS_IDX_NODE,
 376         UBIFS_CS_NODE,
 377         UBIFS_ORPH_NODE,
 378         UBIFS_NODE_TYPES_CNT,
 379 };
 380
 381 /*
 382  * Master node flags.
 383  *
 384  * UBIFS_MST_DIRTY: rebooted uncleanly - master node is dirty
 385  * UBIFS_MST_NO_ORPHS: no orphan inodes present
 386  * UBIFS_MST_RCVRY: written by recovery
 387  */
 388 enum {
 389         UBIFS_MST_DIRTY = 1,
 390         UBIFS_MST_NO_ORPHS = 2,
 391         UBIFS_MST_RCVRY = 4,
 392 };
 393
 394 /*
 395  * Node group type (used by recovery to recover whole group or none).
 396  *
 397  * UBIFS_NO_NODE_GROUP: this node is not part of a group
 398  * UBIFS_IN_NODE_GROUP: this node is a part of a group
 399  * UBIFS_LAST_OF_NODE_GROUP: this node is the last in a group
 400  */
 401 enum {
 402         UBIFS_NO_NODE_GROUP = 0,
 403         UBIFS_IN_NODE_GROUP,
 404         UBIFS_LAST_OF_NODE_GROUP,
 405 };
 406
 407 /*
 408  * Superblock flags.
 409  *
 410  * UBIFS_FLG_BIGLPT: if "big" LPT model is used if set
 411  * UBIFS_FLG_SPACE_FIXUP: first-mount "fixup" of free space within LEBs needed
 412  */
 413 enum {
 414         UBIFS_FLG_BIGLPT = 0x02,
 415         UBIFS_FLG_SPACE_FIXUP = 0x04,
 416 };
 417
 418 /**
 419  * struct ubifs_ch - common header node.
 420  * @magic: UBIFS node magic number (%UBIFS_NODE_MAGIC)
 421  * @crc: CRC-32 checksum of the node header
 422  * @sqnum: sequence number
 423  * @len: full node length
 424  * @node_type: node type
 425  * @group_type: node group type
 426  * @padding: reserved for future, zeroes
 427  *
 428  * Every UBIFS node starts with this common part. If the node has a key, the
 429  * key always goes next.
 430  */
 431 struct ubifs_ch {
 432         __le32 magic;
 433         __le32 crc;
 434         __le64 sqnum;
 435         __le32 len;
 436         __u8 node_type;
 437         __u8 group_type;
 438         __u8 padding[2];
 439 } __packed;
 440
 441 /**
 442  * union ubifs_dev_desc - device node descriptor.
 443  * @new: new type device descriptor
 444  * @huge: huge type device descriptor
 445  *
 446  * This data structure describes major/minor numbers of a device node. In an
 447  * inode is a device node then its data contains an object of this type. UBIFS
 448  * uses standard Linux "new" and "huge" device node encodings.
 449  */
 450 union ubifs_dev_desc {
 451         __le32 new;
 452         __le64 huge;
 453 } __packed;
 454
 455 /**
 456  * struct ubifs_ino_node - inode node.
 457  * @ch: common header
 458  * @key: node key
 459  * @creat_sqnum: sequence number at time of creation
 460  * @size: inode size in bytes (amount of uncompressed data)
 461  * @atime_sec: access time seconds
 462  * @ctime_sec: creation time seconds
 463  * @mtime_sec: modification time seconds
 464  * @atime_nsec: access time nanoseconds
 465  * @ctime_nsec: creation time nanoseconds
 466  * @mtime_nsec: modification time nanoseconds
 467  * @nlink: number of hard links
 468  * @uid: owner ID
 469  * @gid: group ID
 470  * @mode: access flags
 471  * @flags: per-inode flags (%UBIFS_COMPR_FL, %UBIFS_SYNC_FL, etc)
 472  * @data_len: inode data length
 473  * @xattr_cnt: count of extended attributes this inode has
 474  * @xattr_size: summarized size of all extended attributes in bytes
 475  * @padding1: reserved for future, zeroes
 476  * @xattr_names: sum of lengths of all extended attribute names belonging to
 477  *               this inode
 478  * @compr_type: compression type used for this inode
 479  * @padding2: reserved for future, zeroes
 480  * @data: data attached to the inode
 481  *
 482  * Note, even though inode compression type is defined by @compr_type, some
 483  * nodes of this inode may be compressed with different compressor - this
 484  * happens if compression type is changed while the inode already has data
 485  * nodes. But @compr_type will be use for further writes to the inode.
 486  *
 487  * Note, do not forget to amend 'zero_ino_node_unused()' function when changing
 488  * the padding fields.
 489  */
 490 struct ubifs_ino_node {
 491         struct ubifs_ch ch;
 492         __u8 key[UBIFS_MAX_KEY_LEN];
 493         __le64 creat_sqnum;
 494         __le64 size;
 495         __le64 atime_sec;
 496         __le64 ctime_sec;
 497         __le64 mtime_sec;
 498         __le32 atime_nsec;
 499         __le32 ctime_nsec;
 500         __le32 mtime_nsec;
 501         __le32 nlink;
 502         __le32 uid;
 503         __le32 gid;
 504         __le32 mode;
 505         __le32 flags;
 506         __le32 data_len;
 507         __le32 xattr_cnt;
 508         __le32 xattr_size;
 509         __u8 padding1[4]; /* Watch 'zero_ino_node_unused()' if changing! */
 510         __le32 xattr_names;
 511         __le16 compr_type;
 512         __u8 padding2[26]; /* Watch 'zero_ino_node_unused()' if changing! */
 513         __u8 data[];
 514 } __packed;
 515
 516 /**
 517  * struct ubifs_dent_node - directory entry node.
 518  * @ch: common header
 519  * @key: node key
 520  * @inum: target inode number
 521  * @padding1: reserved for future, zeroes
 522  * @type: type of the target inode (%UBIFS_ITYPE_REG, %UBIFS_ITYPE_DIR, etc)
 523  * @nlen: name length
 524  * @padding2: reserved for future, zeroes
 525  * @name: zero-terminated name
 526  *
 527  * Note, do not forget to amend 'zero_dent_node_unused()' function when
 528  * changing the padding fields.
 529  */
 530 struct ubifs_dent_node {
 531         struct ubifs_ch ch;
 532         __u8 key[UBIFS_MAX_KEY_LEN];
 533         __le64 inum;
 534         __u8 padding1;
 535         __u8 type;
 536         __le16 nlen;
 537         __u8 padding2[4]; /* Watch 'zero_dent_node_unused()' if changing! */
 538         __u8 name[];
 539 } __packed;
 540
 541 /**
 542  * struct ubifs_data_node - data node.
 543  * @ch: common header
 544  * @key: node key
 545  * @size: uncompressed data size in bytes
 546  * @compr_type: compression type (%UBIFS_COMPR_NONE, %UBIFS_COMPR_LZO, etc)
 547  * @padding: reserved for future, zeroes
 548  * @data: data
 549  *
 550  * Note, do not forget to amend 'zero_data_node_unused()' function when
 551  * changing the padding fields.
 552  */
 553 struct ubifs_data_node {
 554         struct ubifs_ch ch;
 555         __u8 key[UBIFS_MAX_KEY_LEN];
 556         __le32 size;
 557         __le16 compr_type;
 558         __u8 padding[2]; /* Watch 'zero_data_node_unused()' if changing! */
 559         __u8 data[];
 560 } __packed;
 561
 562 /**
 563  * struct ubifs_trun_node - truncation node.
 564  * @ch: common header
 565  * @inum: truncated inode number
 566  * @padding: reserved for future, zeroes
 567  * @old_size: size before truncation
 568  * @new_size: size after truncation
 569  *
 570  * This node exists only in the journal and never goes to the main area. Note,
 571  * do not forget to amend 'zero_trun_node_unused()' function when changing the
 572  * padding fields.
 573  */
 574 struct ubifs_trun_node {
 575         struct ubifs_ch ch;
 576         __le32 inum;
 577         __u8 padding[12]; /* Watch 'zero_trun_node_unused()' if changing! */
 578         __le64 old_size;
 579         __le64 new_size;
 580 } __packed;
 581
 582 /**
 583  * struct ubifs_pad_node - padding node.
 584  * @ch: common header
 585  * @pad_len: how many bytes after this node are unused (because padded)
 586  * @padding: reserved for future, zeroes
 587  */
 588 struct ubifs_pad_node {
 589         struct ubifs_ch ch;
 590         __le32 pad_len;
 591 } __packed;
 592
 593 /**
 594  * struct ubifs_sb_node - superblock node.
 595  * @ch: common header
 596  * @padding: reserved for future, zeroes
 597  * @key_hash: type of hash function used in keys
 598  * @key_fmt: format of the key
 599  * @flags: file-system flags (%UBIFS_FLG_BIGLPT, etc)
 600  * @min_io_size: minimal input/output unit size
 601  * @leb_size: logical eraseblock size in bytes
 602  * @leb_cnt: count of LEBs used by file-system
 603  * @max_leb_cnt: maximum count of LEBs used by file-system
 604  * @max_bud_bytes: maximum amount of data stored in buds
 605  * @log_lebs: log size in logical eraseblocks
 606  * @lpt_lebs: number of LEBs used for lprops table
 607  * @orph_lebs: number of LEBs used for recording orphans
 608  * @jhead_cnt: count of journal heads
 609  * @fanout: tree fanout (max. number of links per indexing node)
 610  * @lsave_cnt: number of LEB numbers in LPT's save table
 611  * @fmt_version: UBIFS on-flash format version
 612  * @default_compr: default compression algorithm (%UBIFS_COMPR_LZO, etc)
 613  * @padding1: reserved for future, zeroes
 614  * @rp_uid: reserve pool UID
 615  * @rp_gid: reserve pool GID
 616  * @rp_size: size of the reserved pool in bytes
 617  * @padding2: reserved for future, zeroes
 618  * @time_gran: time granularity in nanoseconds
 619  * @uuid: UUID generated when the file system image was created
 620  * @ro_compat_version: UBIFS R/O compatibility version
 621  */
 622 struct ubifs_sb_node {
 623         struct ubifs_ch ch;
 624         __u8 padding[2];
 625         __u8 key_hash;
 626         __u8 key_fmt;
 627         __le32 flags;
 628         __le32 min_io_size;
 629         __le32 leb_size;
 630         __le32 leb_cnt;
 631         __le32 max_leb_cnt;
 632         __le64 max_bud_bytes;
 633         __le32 log_lebs;
 634         __le32 lpt_lebs;
 635         __le32 orph_lebs;
 636         __le32 jhead_cnt;
 637         __le32 fanout;
 638         __le32 lsave_cnt;
 639         __le32 fmt_version;
 640         __le16 default_compr;
 641         __u8 padding1[2];
 642         __le32 rp_uid;
 643         __le32 rp_gid;
 644         __le64 rp_size;
 645         __le32 time_gran;
 646         __u8 uuid[16];
 647         __le32 ro_compat_version;
 648         __u8 padding2[3968];
 649 } __packed;
 650
 651 /**
 652  * struct ubifs_mst_node - master node.
 653  * @ch: common header
 654  * @highest_inum: highest inode number in the committed index
 655  * @cmt_no: commit number
 656  * @flags: various flags (%UBIFS_MST_DIRTY, etc)
 657  * @log_lnum: start of the log
 658  * @root_lnum: LEB number of the root indexing node
 659  * @root_offs: offset within @root_lnum
 660  * @root_len: root indexing node length
 661  * @gc_lnum: LEB reserved for garbage collection (%-1 value means the LEB was
 662  * not reserved and should be reserved on mount)
 663  * @ihead_lnum: LEB number of index head
 664  * @ihead_offs: offset of index head
 665  * @index_size: size of index on flash
 666  * @total_free: total free space in bytes
 667  * @total_dirty: total dirty space in bytes
 668  * @total_used: total used space in bytes (includes only data LEBs)
 669  * @total_dead: total dead space in bytes (includes only data LEBs)
 670  * @total_dark: total dark space in bytes (includes only data LEBs)
 671  * @lpt_lnum: LEB number of LPT root nnode
 672  * @lpt_offs: offset of LPT root nnode
 673  * @nhead_lnum: LEB number of LPT head
 674  * @nhead_offs: offset of LPT head
 675  * @ltab_lnum: LEB number of LPT's own lprops table
 676  * @ltab_offs: offset of LPT's own lprops table
 677  * @lsave_lnum: LEB number of LPT's save table (big model only)
 678  * @lsave_offs: offset of LPT's save table (big model only)
 679  * @lscan_lnum: LEB number of last LPT scan
 680  * @empty_lebs: number of empty logical eraseblocks
 681  * @idx_lebs: number of indexing logical eraseblocks
 682  * @leb_cnt: count of LEBs used by file-system
 683  * @padding: reserved for future, zeroes
 684  */
 685 struct ubifs_mst_node {
 686         struct ubifs_ch ch;
 687         __le64 highest_inum;
 688         __le64 cmt_no;
 689         __le32 flags;
 690         __le32 log_lnum;
 691         __le32 root_lnum;
 692         __le32 root_offs;
 693         __le32 root_len;
 694         __le32 gc_lnum;
 695         __le32 ihead_lnum;
 696         __le32 ihead_offs;
 697         __le64 index_size;
 698         __le64 total_free;
 699         __le64 total_dirty;
 700         __le64 total_used;
 701         __le64 total_dead;
 702         __le64 total_dark;
 703         __le32 lpt_lnum;
 704         __le32 lpt_offs;
 705         __le32 nhead_lnum;
 706         __le32 nhead_offs;
 707         __le32 ltab_lnum;
 708         __le32 ltab_offs;
 709         __le32 lsave_lnum;
 710         __le32 lsave_offs;
 711         __le32 lscan_lnum;
 712         __le32 empty_lebs;
 713         __le32 idx_lebs;
 714         __le32 leb_cnt;
 715         __u8 padding[344];
 716 } __packed;
 717
 718 /**
 719  * struct ubifs_ref_node - logical eraseblock reference node.
 720  * @ch: common header
 721  * @lnum: the referred logical eraseblock number
 722  * @offs: start offset in the referred LEB
 723  * @jhead: journal head number
 724  * @padding: reserved for future, zeroes
 725  */
 726 struct ubifs_ref_node {
 727         struct ubifs_ch ch;
 728         __le32 lnum;
 729         __le32 offs;
 730         __le32 jhead;
 731         __u8 padding[28];
 732 } __packed;
 733
 734 /**
 735  * struct ubifs_branch - key/reference/length branch
 736  * @lnum: LEB number of the target node
 737  * @offs: offset within @lnum
 738  * @len: target node length
 739  * @key: key
 740  */
 741 struct ubifs_branch {
 742         __le32 lnum;
 743         __le32 offs;
 744         __le32 len;
 745         __u8 key[];
 746 } __packed;
 747
 748 /**
 749  * struct ubifs_idx_node - indexing node.
 750  * @ch: common header
 751  * @child_cnt: number of child index nodes
 752  * @level: tree level
 753  * @branches: LEB number / offset / length / key branches
 754  */
 755 struct ubifs_idx_node {
 756         struct ubifs_ch ch;
 757         __le16 child_cnt;
 758         __le16 level;
 759         __u8 branches[];
 760 } __packed;
 761
 762 /**
 763  * struct ubifs_cs_node - commit start node.
 764  * @ch: common header
 765  * @cmt_no: commit number
 766  */
 767 struct ubifs_cs_node {
 768         struct ubifs_ch ch;
 769         __le64 cmt_no;
 770 } __packed;
 771
 772 /**
 773  * struct ubifs_orph_node - orphan node.
 774  * @ch: common header
 775  * @cmt_no: commit number (also top bit is set on the last node of the commit)
 776  * @inos: inode numbers of orphans
 777  */
 778 struct ubifs_orph_node {
 779         struct ubifs_ch ch;
 780         __le64 cmt_no;
 781         __le64 inos[];
 782 } __packed;
 783
 784 #endif /* __UBIFS_MEDIA_H__ */