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 5
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  * xattr name of UBIFS encryption context, we don't use a prefix
305  * nor a long name to not waste space on the flash.
306  */
307 #define UBIFS_XATTR_NAME_ENCRYPTION_CONTEXT "c"
308 
309 
310 /*
311  * On-flash inode flags.
312  *
313  * UBIFS_COMPR_FL: use compression for this inode
314  * UBIFS_SYNC_FL:  I/O on this inode has to be synchronous
315  * UBIFS_IMMUTABLE_FL: inode is immutable
316  * UBIFS_APPEND_FL: writes to the inode may only append data
317  * UBIFS_DIRSYNC_FL: I/O on this directory inode has to be synchronous
318  * UBIFS_XATTR_FL: this inode is the inode for an extended attribute value
319  * UBIFS_CRYPT_FL: use encryption for this inode
320  *
321  * Note, these are on-flash flags which correspond to ioctl flags
322  * (@FS_COMPR_FL, etc). They have the same values now, but generally, do not
323  * have to be the same.
324  */
325 enum {
326 	UBIFS_COMPR_FL     = 0x01,
327 	UBIFS_SYNC_FL      = 0x02,
328 	UBIFS_IMMUTABLE_FL = 0x04,
329 	UBIFS_APPEND_FL    = 0x08,
330 	UBIFS_DIRSYNC_FL   = 0x10,
331 	UBIFS_XATTR_FL     = 0x20,
332 	UBIFS_CRYPT_FL     = 0x40,
333 };
334 
335 /* Inode flag bits used by UBIFS */
336 #define UBIFS_FL_MASK 0x0000001F
337 
338 /*
339  * UBIFS compression algorithms.
340  *
341  * UBIFS_COMPR_NONE: no compression
342  * UBIFS_COMPR_LZO: LZO compression
343  * UBIFS_COMPR_ZLIB: ZLIB compression
344  * UBIFS_COMPR_TYPES_CNT: count of supported compression types
345  */
346 enum {
347 	UBIFS_COMPR_NONE,
348 	UBIFS_COMPR_LZO,
349 	UBIFS_COMPR_ZLIB,
350 	UBIFS_COMPR_TYPES_CNT,
351 };
352 
353 /*
354  * UBIFS node types.
355  *
356  * UBIFS_INO_NODE: inode node
357  * UBIFS_DATA_NODE: data node
358  * UBIFS_DENT_NODE: directory entry node
359  * UBIFS_XENT_NODE: extended attribute node
360  * UBIFS_TRUN_NODE: truncation node
361  * UBIFS_PAD_NODE: padding node
362  * UBIFS_SB_NODE: superblock node
363  * UBIFS_MST_NODE: master node
364  * UBIFS_REF_NODE: LEB reference node
365  * UBIFS_IDX_NODE: index node
366  * UBIFS_CS_NODE: commit start node
367  * UBIFS_ORPH_NODE: orphan node
368  * UBIFS_NODE_TYPES_CNT: count of supported node types
369  *
370  * Note, we index arrays by these numbers, so keep them low and contiguous.
371  * Node type constants for inodes, direntries and so on have to be the same as
372  * corresponding key type constants.
373  */
374 enum {
375 	UBIFS_INO_NODE,
376 	UBIFS_DATA_NODE,
377 	UBIFS_DENT_NODE,
378 	UBIFS_XENT_NODE,
379 	UBIFS_TRUN_NODE,
380 	UBIFS_PAD_NODE,
381 	UBIFS_SB_NODE,
382 	UBIFS_MST_NODE,
383 	UBIFS_REF_NODE,
384 	UBIFS_IDX_NODE,
385 	UBIFS_CS_NODE,
386 	UBIFS_ORPH_NODE,
387 	UBIFS_NODE_TYPES_CNT,
388 };
389 
390 /*
391  * Master node flags.
392  *
393  * UBIFS_MST_DIRTY: rebooted uncleanly - master node is dirty
394  * UBIFS_MST_NO_ORPHS: no orphan inodes present
395  * UBIFS_MST_RCVRY: written by recovery
396  */
397 enum {
398 	UBIFS_MST_DIRTY = 1,
399 	UBIFS_MST_NO_ORPHS = 2,
400 	UBIFS_MST_RCVRY = 4,
401 };
402 
403 /*
404  * Node group type (used by recovery to recover whole group or none).
405  *
406  * UBIFS_NO_NODE_GROUP: this node is not part of a group
407  * UBIFS_IN_NODE_GROUP: this node is a part of a group
408  * UBIFS_LAST_OF_NODE_GROUP: this node is the last in a group
409  */
410 enum {
411 	UBIFS_NO_NODE_GROUP = 0,
412 	UBIFS_IN_NODE_GROUP,
413 	UBIFS_LAST_OF_NODE_GROUP,
414 };
415 
416 /*
417  * Superblock flags.
418  *
419  * UBIFS_FLG_BIGLPT: if "big" LPT model is used if set
420  * UBIFS_FLG_SPACE_FIXUP: first-mount "fixup" of free space within LEBs needed
421  * UBIFS_FLG_DOUBLE_HASH: store a 32bit cookie in directory entry nodes to
422  *			  support 64bit cookies for lookups by hash
423  * UBIFS_FLG_ENCRYPTION: this filesystem contains encrypted files
424  */
425 enum {
426 	UBIFS_FLG_BIGLPT = 0x02,
427 	UBIFS_FLG_SPACE_FIXUP = 0x04,
428 	UBIFS_FLG_DOUBLE_HASH = 0x08,
429 	UBIFS_FLG_ENCRYPTION = 0x10,
430 };
431 
432 #define UBIFS_FLG_MASK (UBIFS_FLG_BIGLPT|UBIFS_FLG_SPACE_FIXUP|UBIFS_FLG_DOUBLE_HASH|UBIFS_FLG_ENCRYPTION)
433 
434 /**
435  * struct ubifs_ch - common header node.
436  * @magic: UBIFS node magic number (%UBIFS_NODE_MAGIC)
437  * @crc: CRC-32 checksum of the node header
438  * @sqnum: sequence number
439  * @len: full node length
440  * @node_type: node type
441  * @group_type: node group type
442  * @padding: reserved for future, zeroes
443  *
444  * Every UBIFS node starts with this common part. If the node has a key, the
445  * key always goes next.
446  */
447 struct ubifs_ch {
448 	__le32 magic;
449 	__le32 crc;
450 	__le64 sqnum;
451 	__le32 len;
452 	__u8 node_type;
453 	__u8 group_type;
454 	__u8 padding[2];
455 } __packed;
456 
457 /**
458  * union ubifs_dev_desc - device node descriptor.
459  * @new: new type device descriptor
460  * @huge: huge type device descriptor
461  *
462  * This data structure describes major/minor numbers of a device node. In an
463  * inode is a device node then its data contains an object of this type. UBIFS
464  * uses standard Linux "new" and "huge" device node encodings.
465  */
466 union ubifs_dev_desc {
467 	__le32 new;
468 	__le64 huge;
469 } __packed;
470 
471 /**
472  * struct ubifs_ino_node - inode node.
473  * @ch: common header
474  * @key: node key
475  * @creat_sqnum: sequence number at time of creation
476  * @size: inode size in bytes (amount of uncompressed data)
477  * @atime_sec: access time seconds
478  * @ctime_sec: creation time seconds
479  * @mtime_sec: modification time seconds
480  * @atime_nsec: access time nanoseconds
481  * @ctime_nsec: creation time nanoseconds
482  * @mtime_nsec: modification time nanoseconds
483  * @nlink: number of hard links
484  * @uid: owner ID
485  * @gid: group ID
486  * @mode: access flags
487  * @flags: per-inode flags (%UBIFS_COMPR_FL, %UBIFS_SYNC_FL, etc)
488  * @data_len: inode data length
489  * @xattr_cnt: count of extended attributes this inode has
490  * @xattr_size: summarized size of all extended attributes in bytes
491  * @padding1: reserved for future, zeroes
492  * @xattr_names: sum of lengths of all extended attribute names belonging to
493  *               this inode
494  * @compr_type: compression type used for this inode
495  * @padding2: reserved for future, zeroes
496  * @data: data attached to the inode
497  *
498  * Note, even though inode compression type is defined by @compr_type, some
499  * nodes of this inode may be compressed with different compressor - this
500  * happens if compression type is changed while the inode already has data
501  * nodes. But @compr_type will be use for further writes to the inode.
502  *
503  * Note, do not forget to amend 'zero_ino_node_unused()' function when changing
504  * the padding fields.
505  */
506 struct ubifs_ino_node {
507 	struct ubifs_ch ch;
508 	__u8 key[UBIFS_MAX_KEY_LEN];
509 	__le64 creat_sqnum;
510 	__le64 size;
511 	__le64 atime_sec;
512 	__le64 ctime_sec;
513 	__le64 mtime_sec;
514 	__le32 atime_nsec;
515 	__le32 ctime_nsec;
516 	__le32 mtime_nsec;
517 	__le32 nlink;
518 	__le32 uid;
519 	__le32 gid;
520 	__le32 mode;
521 	__le32 flags;
522 	__le32 data_len;
523 	__le32 xattr_cnt;
524 	__le32 xattr_size;
525 	__u8 padding1[4]; /* Watch 'zero_ino_node_unused()' if changing! */
526 	__le32 xattr_names;
527 	__le16 compr_type;
528 	__u8 padding2[26]; /* Watch 'zero_ino_node_unused()' if changing! */
529 	__u8 data[];
530 } __packed;
531 
532 /**
533  * struct ubifs_dent_node - directory entry node.
534  * @ch: common header
535  * @key: node key
536  * @inum: target inode number
537  * @padding1: reserved for future, zeroes
538  * @type: type of the target inode (%UBIFS_ITYPE_REG, %UBIFS_ITYPE_DIR, etc)
539  * @nlen: name length
540  * @cookie: A 32bits random number, used to construct a 64bits
541  *          identifier.
542  * @name: zero-terminated name
543  *
544  * Note, do not forget to amend 'zero_dent_node_unused()' function when
545  * changing the padding fields.
546  */
547 struct ubifs_dent_node {
548 	struct ubifs_ch ch;
549 	__u8 key[UBIFS_MAX_KEY_LEN];
550 	__le64 inum;
551 	__u8 padding1;
552 	__u8 type;
553 	__le16 nlen;
554 	__le32 cookie;
555 	__u8 name[];
556 } __packed;
557 
558 /**
559  * struct ubifs_data_node - data node.
560  * @ch: common header
561  * @key: node key
562  * @size: uncompressed data size in bytes
563  * @compr_type: compression type (%UBIFS_COMPR_NONE, %UBIFS_COMPR_LZO, etc)
564  * @compr_size: compressed data size in bytes, only valid when data is encrypted
565  * @data: data
566  *
567  */
568 struct ubifs_data_node {
569 	struct ubifs_ch ch;
570 	__u8 key[UBIFS_MAX_KEY_LEN];
571 	__le32 size;
572 	__le16 compr_type;
573 	__le16 compr_size;
574 	__u8 data[];
575 } __packed;
576 
577 /**
578  * struct ubifs_trun_node - truncation node.
579  * @ch: common header
580  * @inum: truncated inode number
581  * @padding: reserved for future, zeroes
582  * @old_size: size before truncation
583  * @new_size: size after truncation
584  *
585  * This node exists only in the journal and never goes to the main area. Note,
586  * do not forget to amend 'zero_trun_node_unused()' function when changing the
587  * padding fields.
588  */
589 struct ubifs_trun_node {
590 	struct ubifs_ch ch;
591 	__le32 inum;
592 	__u8 padding[12]; /* Watch 'zero_trun_node_unused()' if changing! */
593 	__le64 old_size;
594 	__le64 new_size;
595 } __packed;
596 
597 /**
598  * struct ubifs_pad_node - padding node.
599  * @ch: common header
600  * @pad_len: how many bytes after this node are unused (because padded)
601  * @padding: reserved for future, zeroes
602  */
603 struct ubifs_pad_node {
604 	struct ubifs_ch ch;
605 	__le32 pad_len;
606 } __packed;
607 
608 /**
609  * struct ubifs_sb_node - superblock node.
610  * @ch: common header
611  * @padding: reserved for future, zeroes
612  * @key_hash: type of hash function used in keys
613  * @key_fmt: format of the key
614  * @flags: file-system flags (%UBIFS_FLG_BIGLPT, etc)
615  * @min_io_size: minimal input/output unit size
616  * @leb_size: logical eraseblock size in bytes
617  * @leb_cnt: count of LEBs used by file-system
618  * @max_leb_cnt: maximum count of LEBs used by file-system
619  * @max_bud_bytes: maximum amount of data stored in buds
620  * @log_lebs: log size in logical eraseblocks
621  * @lpt_lebs: number of LEBs used for lprops table
622  * @orph_lebs: number of LEBs used for recording orphans
623  * @jhead_cnt: count of journal heads
624  * @fanout: tree fanout (max. number of links per indexing node)
625  * @lsave_cnt: number of LEB numbers in LPT's save table
626  * @fmt_version: UBIFS on-flash format version
627  * @default_compr: default compression algorithm (%UBIFS_COMPR_LZO, etc)
628  * @padding1: reserved for future, zeroes
629  * @rp_uid: reserve pool UID
630  * @rp_gid: reserve pool GID
631  * @rp_size: size of the reserved pool in bytes
632  * @padding2: reserved for future, zeroes
633  * @time_gran: time granularity in nanoseconds
634  * @uuid: UUID generated when the file system image was created
635  * @ro_compat_version: UBIFS R/O compatibility version
636  */
637 struct ubifs_sb_node {
638 	struct ubifs_ch ch;
639 	__u8 padding[2];
640 	__u8 key_hash;
641 	__u8 key_fmt;
642 	__le32 flags;
643 	__le32 min_io_size;
644 	__le32 leb_size;
645 	__le32 leb_cnt;
646 	__le32 max_leb_cnt;
647 	__le64 max_bud_bytes;
648 	__le32 log_lebs;
649 	__le32 lpt_lebs;
650 	__le32 orph_lebs;
651 	__le32 jhead_cnt;
652 	__le32 fanout;
653 	__le32 lsave_cnt;
654 	__le32 fmt_version;
655 	__le16 default_compr;
656 	__u8 padding1[2];
657 	__le32 rp_uid;
658 	__le32 rp_gid;
659 	__le64 rp_size;
660 	__le32 time_gran;
661 	__u8 uuid[16];
662 	__le32 ro_compat_version;
663 	__u8 padding2[3968];
664 } __packed;
665 
666 /**
667  * struct ubifs_mst_node - master node.
668  * @ch: common header
669  * @highest_inum: highest inode number in the committed index
670  * @cmt_no: commit number
671  * @flags: various flags (%UBIFS_MST_DIRTY, etc)
672  * @log_lnum: start of the log
673  * @root_lnum: LEB number of the root indexing node
674  * @root_offs: offset within @root_lnum
675  * @root_len: root indexing node length
676  * @gc_lnum: LEB reserved for garbage collection (%-1 value means the LEB was
677  * not reserved and should be reserved on mount)
678  * @ihead_lnum: LEB number of index head
679  * @ihead_offs: offset of index head
680  * @index_size: size of index on flash
681  * @total_free: total free space in bytes
682  * @total_dirty: total dirty space in bytes
683  * @total_used: total used space in bytes (includes only data LEBs)
684  * @total_dead: total dead space in bytes (includes only data LEBs)
685  * @total_dark: total dark space in bytes (includes only data LEBs)
686  * @lpt_lnum: LEB number of LPT root nnode
687  * @lpt_offs: offset of LPT root nnode
688  * @nhead_lnum: LEB number of LPT head
689  * @nhead_offs: offset of LPT head
690  * @ltab_lnum: LEB number of LPT's own lprops table
691  * @ltab_offs: offset of LPT's own lprops table
692  * @lsave_lnum: LEB number of LPT's save table (big model only)
693  * @lsave_offs: offset of LPT's save table (big model only)
694  * @lscan_lnum: LEB number of last LPT scan
695  * @empty_lebs: number of empty logical eraseblocks
696  * @idx_lebs: number of indexing logical eraseblocks
697  * @leb_cnt: count of LEBs used by file-system
698  * @padding: reserved for future, zeroes
699  */
700 struct ubifs_mst_node {
701 	struct ubifs_ch ch;
702 	__le64 highest_inum;
703 	__le64 cmt_no;
704 	__le32 flags;
705 	__le32 log_lnum;
706 	__le32 root_lnum;
707 	__le32 root_offs;
708 	__le32 root_len;
709 	__le32 gc_lnum;
710 	__le32 ihead_lnum;
711 	__le32 ihead_offs;
712 	__le64 index_size;
713 	__le64 total_free;
714 	__le64 total_dirty;
715 	__le64 total_used;
716 	__le64 total_dead;
717 	__le64 total_dark;
718 	__le32 lpt_lnum;
719 	__le32 lpt_offs;
720 	__le32 nhead_lnum;
721 	__le32 nhead_offs;
722 	__le32 ltab_lnum;
723 	__le32 ltab_offs;
724 	__le32 lsave_lnum;
725 	__le32 lsave_offs;
726 	__le32 lscan_lnum;
727 	__le32 empty_lebs;
728 	__le32 idx_lebs;
729 	__le32 leb_cnt;
730 	__u8 padding[344];
731 } __packed;
732 
733 /**
734  * struct ubifs_ref_node - logical eraseblock reference node.
735  * @ch: common header
736  * @lnum: the referred logical eraseblock number
737  * @offs: start offset in the referred LEB
738  * @jhead: journal head number
739  * @padding: reserved for future, zeroes
740  */
741 struct ubifs_ref_node {
742 	struct ubifs_ch ch;
743 	__le32 lnum;
744 	__le32 offs;
745 	__le32 jhead;
746 	__u8 padding[28];
747 } __packed;
748 
749 /**
750  * struct ubifs_branch - key/reference/length branch
751  * @lnum: LEB number of the target node
752  * @offs: offset within @lnum
753  * @len: target node length
754  * @key: key
755  */
756 struct ubifs_branch {
757 	__le32 lnum;
758 	__le32 offs;
759 	__le32 len;
760 	__u8 key[];
761 } __packed;
762 
763 /**
764  * struct ubifs_idx_node - indexing node.
765  * @ch: common header
766  * @child_cnt: number of child index nodes
767  * @level: tree level
768  * @branches: LEB number / offset / length / key branches
769  */
770 struct ubifs_idx_node {
771 	struct ubifs_ch ch;
772 	__le16 child_cnt;
773 	__le16 level;
774 	__u8 branches[];
775 } __packed;
776 
777 /**
778  * struct ubifs_cs_node - commit start node.
779  * @ch: common header
780  * @cmt_no: commit number
781  */
782 struct ubifs_cs_node {
783 	struct ubifs_ch ch;
784 	__le64 cmt_no;
785 } __packed;
786 
787 /**
788  * struct ubifs_orph_node - orphan node.
789  * @ch: common header
790  * @cmt_no: commit number (also top bit is set on the last node of the commit)
791  * @inos: inode numbers of orphans
792  */
793 struct ubifs_orph_node {
794 	struct ubifs_ch ch;
795 	__le64 cmt_no;
796 	__le64 inos[];
797 } __packed;
798 
799 #endif /* __UBIFS_MEDIA_H__ */
800