xref: /linux/fs/ubifs/ubifs-media.h (revision b7019ac550eb3916f34d79db583e9b7ea2524afa)
1 /* SPDX-License-Identifier: GPL-2.0-only */
2 /*
3  * This file is part of UBIFS.
4  *
5  * Copyright (C) 2006-2008 Nokia Corporation.
6  *
7  * Authors: Artem Bityutskiy (Битюцкий Артём)
8  *          Adrian Hunter
9  */
10 
11 /*
12  * This file describes UBIFS on-flash format and contains definitions of all the
13  * relevant data structures and constants.
14  *
15  * All UBIFS on-flash objects are stored in the form of nodes. All nodes start
16  * with the UBIFS node magic number and have the same common header. Nodes
17  * always sit at 8-byte aligned positions on the media and node header sizes are
18  * also 8-byte aligned (except for the indexing node and the padding node).
19  */
20 
21 #ifndef __UBIFS_MEDIA_H__
22 #define __UBIFS_MEDIA_H__
23 
24 /* UBIFS node magic number (must not have the padding byte first or last) */
25 #define UBIFS_NODE_MAGIC  0x06101831
26 
27 /*
28  * UBIFS on-flash format version. This version is increased when the on-flash
29  * format is changing. If this happens, UBIFS is will support older versions as
30  * well. But older UBIFS code will not support newer formats. Format changes
31  * will be rare and only when absolutely necessary, e.g. to fix a bug or to add
32  * a new feature.
33  *
34  * UBIFS went into mainline kernel with format version 4. The older formats
35  * were development formats.
36  */
37 #define UBIFS_FORMAT_VERSION 5
38 
39 /*
40  * Read-only compatibility version. If the UBIFS format is changed, older UBIFS
41  * implementations will not be able to mount newer formats in read-write mode.
42  * However, depending on the change, it may be possible to mount newer formats
43  * in R/O mode. This is indicated by the R/O compatibility version which is
44  * stored in the super-block.
45  *
46  * This is needed to support boot-loaders which only need R/O mounting. With
47  * this flag it is possible to do UBIFS format changes without a need to update
48  * boot-loaders.
49  */
50 #define UBIFS_RO_COMPAT_VERSION 0
51 
52 /* Minimum logical eraseblock size in bytes */
53 #define UBIFS_MIN_LEB_SZ (15*1024)
54 
55 /* Initial CRC32 value used when calculating CRC checksums */
56 #define UBIFS_CRC32_INIT 0xFFFFFFFFU
57 
58 /*
59  * UBIFS does not try to compress data if its length is less than the below
60  * constant.
61  */
62 #define UBIFS_MIN_COMPR_LEN 128
63 
64 /*
65  * If compressed data length is less than %UBIFS_MIN_COMPRESS_DIFF bytes
66  * shorter than uncompressed data length, UBIFS prefers to leave this data
67  * node uncompress, because it'll be read faster.
68  */
69 #define UBIFS_MIN_COMPRESS_DIFF 64
70 
71 /* Root inode number */
72 #define UBIFS_ROOT_INO 1
73 
74 /* Lowest inode number used for regular inodes (not UBIFS-only internal ones) */
75 #define UBIFS_FIRST_INO 64
76 
77 /*
78  * Maximum file name and extended attribute length (must be a multiple of 8,
79  * minus 1).
80  */
81 #define UBIFS_MAX_NLEN 255
82 
83 /* Maximum number of data journal heads */
84 #define UBIFS_MAX_JHEADS 1
85 
86 /*
87  * Size of UBIFS data block. Note, UBIFS is not a block oriented file-system,
88  * which means that it does not treat the underlying media as consisting of
89  * blocks like in case of hard drives. Do not be confused. UBIFS block is just
90  * the maximum amount of data which one data node can have or which can be
91  * attached to an inode node.
92  */
93 #define UBIFS_BLOCK_SIZE  4096
94 #define UBIFS_BLOCK_SHIFT 12
95 
96 /* UBIFS padding byte pattern (must not be first or last byte of node magic) */
97 #define UBIFS_PADDING_BYTE 0xCE
98 
99 /* Maximum possible key length */
100 #define UBIFS_MAX_KEY_LEN 16
101 
102 /* Key length ("simple" format) */
103 #define UBIFS_SK_LEN 8
104 
105 /* Minimum index tree fanout */
106 #define UBIFS_MIN_FANOUT 3
107 
108 /* Maximum number of levels in UBIFS indexing B-tree */
109 #define UBIFS_MAX_LEVELS 512
110 
111 /* Maximum amount of data attached to an inode in bytes */
112 #define UBIFS_MAX_INO_DATA UBIFS_BLOCK_SIZE
113 
114 /* LEB Properties Tree fanout (must be power of 2) and fanout shift */
115 #define UBIFS_LPT_FANOUT 4
116 #define UBIFS_LPT_FANOUT_SHIFT 2
117 
118 /* LEB Properties Tree bit field sizes */
119 #define UBIFS_LPT_CRC_BITS 16
120 #define UBIFS_LPT_CRC_BYTES 2
121 #define UBIFS_LPT_TYPE_BITS 4
122 
123 /* The key is always at the same position in all keyed nodes */
124 #define UBIFS_KEY_OFFSET offsetof(struct ubifs_ino_node, key)
125 
126 /* Garbage collector journal head number */
127 #define UBIFS_GC_HEAD   0
128 /* Base journal head number */
129 #define UBIFS_BASE_HEAD 1
130 /* Data journal head number */
131 #define UBIFS_DATA_HEAD 2
132 
133 /*
134  * LEB Properties Tree node types.
135  *
136  * UBIFS_LPT_PNODE: LPT leaf node (contains LEB properties)
137  * UBIFS_LPT_NNODE: LPT internal node
138  * UBIFS_LPT_LTAB: LPT's own lprops table
139  * UBIFS_LPT_LSAVE: LPT's save table (big model only)
140  * UBIFS_LPT_NODE_CNT: count of LPT node types
141  * UBIFS_LPT_NOT_A_NODE: all ones (15 for 4 bits) is never a valid node type
142  */
143 enum {
144 	UBIFS_LPT_PNODE,
145 	UBIFS_LPT_NNODE,
146 	UBIFS_LPT_LTAB,
147 	UBIFS_LPT_LSAVE,
148 	UBIFS_LPT_NODE_CNT,
149 	UBIFS_LPT_NOT_A_NODE = (1 << UBIFS_LPT_TYPE_BITS) - 1,
150 };
151 
152 /*
153  * UBIFS inode types.
154  *
155  * UBIFS_ITYPE_REG: regular file
156  * UBIFS_ITYPE_DIR: directory
157  * UBIFS_ITYPE_LNK: soft link
158  * UBIFS_ITYPE_BLK: block device node
159  * UBIFS_ITYPE_CHR: character device node
160  * UBIFS_ITYPE_FIFO: fifo
161  * UBIFS_ITYPE_SOCK: socket
162  * UBIFS_ITYPES_CNT: count of supported file types
163  */
164 enum {
165 	UBIFS_ITYPE_REG,
166 	UBIFS_ITYPE_DIR,
167 	UBIFS_ITYPE_LNK,
168 	UBIFS_ITYPE_BLK,
169 	UBIFS_ITYPE_CHR,
170 	UBIFS_ITYPE_FIFO,
171 	UBIFS_ITYPE_SOCK,
172 	UBIFS_ITYPES_CNT,
173 };
174 
175 /*
176  * Supported key hash functions.
177  *
178  * UBIFS_KEY_HASH_R5: R5 hash
179  * UBIFS_KEY_HASH_TEST: test hash which just returns first 4 bytes of the name
180  */
181 enum {
182 	UBIFS_KEY_HASH_R5,
183 	UBIFS_KEY_HASH_TEST,
184 };
185 
186 /*
187  * Supported key formats.
188  *
189  * UBIFS_SIMPLE_KEY_FMT: simple key format
190  */
191 enum {
192 	UBIFS_SIMPLE_KEY_FMT,
193 };
194 
195 /*
196  * The simple key format uses 29 bits for storing UBIFS block number and hash
197  * value.
198  */
199 #define UBIFS_S_KEY_BLOCK_BITS 29
200 #define UBIFS_S_KEY_BLOCK_MASK 0x1FFFFFFF
201 #define UBIFS_S_KEY_HASH_BITS  UBIFS_S_KEY_BLOCK_BITS
202 #define UBIFS_S_KEY_HASH_MASK  UBIFS_S_KEY_BLOCK_MASK
203 
204 /*
205  * Key types.
206  *
207  * UBIFS_INO_KEY: inode node key
208  * UBIFS_DATA_KEY: data node key
209  * UBIFS_DENT_KEY: directory entry node key
210  * UBIFS_XENT_KEY: extended attribute entry key
211  * UBIFS_KEY_TYPES_CNT: number of supported key types
212  */
213 enum {
214 	UBIFS_INO_KEY,
215 	UBIFS_DATA_KEY,
216 	UBIFS_DENT_KEY,
217 	UBIFS_XENT_KEY,
218 	UBIFS_KEY_TYPES_CNT,
219 };
220 
221 /* Count of LEBs reserved for the superblock area */
222 #define UBIFS_SB_LEBS 1
223 /* Count of LEBs reserved for the master area */
224 #define UBIFS_MST_LEBS 2
225 
226 /* First LEB of the superblock area */
227 #define UBIFS_SB_LNUM 0
228 /* First LEB of the master area */
229 #define UBIFS_MST_LNUM (UBIFS_SB_LNUM + UBIFS_SB_LEBS)
230 /* First LEB of the log area */
231 #define UBIFS_LOG_LNUM (UBIFS_MST_LNUM + UBIFS_MST_LEBS)
232 
233 /*
234  * The below constants define the absolute minimum values for various UBIFS
235  * media areas. Many of them actually depend of flash geometry and the FS
236  * configuration (number of journal heads, orphan LEBs, etc). This means that
237  * the smallest volume size which can be used for UBIFS cannot be pre-defined
238  * by these constants. The file-system that meets the below limitation will not
239  * necessarily mount. UBIFS does run-time calculations and validates the FS
240  * size.
241  */
242 
243 /* Minimum number of logical eraseblocks in the log */
244 #define UBIFS_MIN_LOG_LEBS 2
245 /* Minimum number of bud logical eraseblocks (one for each head) */
246 #define UBIFS_MIN_BUD_LEBS 3
247 /* Minimum number of journal logical eraseblocks */
248 #define UBIFS_MIN_JNL_LEBS (UBIFS_MIN_LOG_LEBS + UBIFS_MIN_BUD_LEBS)
249 /* Minimum number of LPT area logical eraseblocks */
250 #define UBIFS_MIN_LPT_LEBS 2
251 /* Minimum number of orphan area logical eraseblocks */
252 #define UBIFS_MIN_ORPH_LEBS 1
253 /*
254  * Minimum number of main area logical eraseblocks (buds, 3 for the index, 1
255  * for GC, 1 for deletions, and at least 1 for committed data).
256  */
257 #define UBIFS_MIN_MAIN_LEBS (UBIFS_MIN_BUD_LEBS + 6)
258 
259 /* Minimum number of logical eraseblocks */
260 #define UBIFS_MIN_LEB_CNT (UBIFS_SB_LEBS + UBIFS_MST_LEBS + \
261 			   UBIFS_MIN_LOG_LEBS + UBIFS_MIN_LPT_LEBS + \
262 			   UBIFS_MIN_ORPH_LEBS + UBIFS_MIN_MAIN_LEBS)
263 
264 /* Node sizes (N.B. these are guaranteed to be multiples of 8) */
265 #define UBIFS_CH_SZ        sizeof(struct ubifs_ch)
266 #define UBIFS_INO_NODE_SZ  sizeof(struct ubifs_ino_node)
267 #define UBIFS_DATA_NODE_SZ sizeof(struct ubifs_data_node)
268 #define UBIFS_DENT_NODE_SZ sizeof(struct ubifs_dent_node)
269 #define UBIFS_TRUN_NODE_SZ sizeof(struct ubifs_trun_node)
270 #define UBIFS_PAD_NODE_SZ  sizeof(struct ubifs_pad_node)
271 #define UBIFS_SB_NODE_SZ   sizeof(struct ubifs_sb_node)
272 #define UBIFS_MST_NODE_SZ  sizeof(struct ubifs_mst_node)
273 #define UBIFS_REF_NODE_SZ  sizeof(struct ubifs_ref_node)
274 #define UBIFS_IDX_NODE_SZ  sizeof(struct ubifs_idx_node)
275 #define UBIFS_CS_NODE_SZ   sizeof(struct ubifs_cs_node)
276 #define UBIFS_ORPH_NODE_SZ sizeof(struct ubifs_orph_node)
277 #define UBIFS_AUTH_NODE_SZ sizeof(struct ubifs_auth_node)
278 /* Extended attribute entry nodes are identical to directory entry nodes */
279 #define UBIFS_XENT_NODE_SZ UBIFS_DENT_NODE_SZ
280 /* Only this does not have to be multiple of 8 bytes */
281 #define UBIFS_BRANCH_SZ    sizeof(struct ubifs_branch)
282 
283 /* Maximum node sizes (N.B. these are guaranteed to be multiples of 8) */
284 #define UBIFS_MAX_DATA_NODE_SZ  (UBIFS_DATA_NODE_SZ + UBIFS_BLOCK_SIZE)
285 #define UBIFS_MAX_INO_NODE_SZ   (UBIFS_INO_NODE_SZ + UBIFS_MAX_INO_DATA)
286 #define UBIFS_MAX_DENT_NODE_SZ  (UBIFS_DENT_NODE_SZ + UBIFS_MAX_NLEN + 1)
287 #define UBIFS_MAX_XENT_NODE_SZ  UBIFS_MAX_DENT_NODE_SZ
288 
289 /* The largest UBIFS node */
290 #define UBIFS_MAX_NODE_SZ UBIFS_MAX_INO_NODE_SZ
291 
292 /* The maxmimum size of a hash, enough for sha512 */
293 #define UBIFS_MAX_HASH_LEN 64
294 
295 /* The maxmimum size of a hmac, enough for hmac(sha512) */
296 #define UBIFS_MAX_HMAC_LEN 64
297 
298 /*
299  * xattr name of UBIFS encryption context, we don't use a prefix
300  * nor a long name to not waste space on the flash.
301  */
302 #define UBIFS_XATTR_NAME_ENCRYPTION_CONTEXT "c"
303 
304 
305 /*
306  * On-flash inode flags.
307  *
308  * UBIFS_COMPR_FL: use compression for this inode
309  * UBIFS_SYNC_FL:  I/O on this inode has to be synchronous
310  * UBIFS_IMMUTABLE_FL: inode is immutable
311  * UBIFS_APPEND_FL: writes to the inode may only append data
312  * UBIFS_DIRSYNC_FL: I/O on this directory inode has to be synchronous
313  * UBIFS_XATTR_FL: this inode is the inode for an extended attribute value
314  * UBIFS_CRYPT_FL: use encryption for this inode
315  *
316  * Note, these are on-flash flags which correspond to ioctl flags
317  * (@FS_COMPR_FL, etc). They have the same values now, but generally, do not
318  * have to be the same.
319  */
320 enum {
321 	UBIFS_COMPR_FL     = 0x01,
322 	UBIFS_SYNC_FL      = 0x02,
323 	UBIFS_IMMUTABLE_FL = 0x04,
324 	UBIFS_APPEND_FL    = 0x08,
325 	UBIFS_DIRSYNC_FL   = 0x10,
326 	UBIFS_XATTR_FL     = 0x20,
327 	UBIFS_CRYPT_FL     = 0x40,
328 };
329 
330 /* Inode flag bits used by UBIFS */
331 #define UBIFS_FL_MASK 0x0000001F
332 
333 /*
334  * UBIFS compression algorithms.
335  *
336  * UBIFS_COMPR_NONE: no compression
337  * UBIFS_COMPR_LZO: LZO compression
338  * UBIFS_COMPR_ZLIB: ZLIB compression
339  * UBIFS_COMPR_TYPES_CNT: count of supported compression types
340  */
341 enum {
342 	UBIFS_COMPR_NONE,
343 	UBIFS_COMPR_LZO,
344 	UBIFS_COMPR_ZLIB,
345 	UBIFS_COMPR_TYPES_CNT,
346 };
347 
348 /*
349  * UBIFS node types.
350  *
351  * UBIFS_INO_NODE: inode node
352  * UBIFS_DATA_NODE: data node
353  * UBIFS_DENT_NODE: directory entry node
354  * UBIFS_XENT_NODE: extended attribute node
355  * UBIFS_TRUN_NODE: truncation node
356  * UBIFS_PAD_NODE: padding node
357  * UBIFS_SB_NODE: superblock node
358  * UBIFS_MST_NODE: master node
359  * UBIFS_REF_NODE: LEB reference node
360  * UBIFS_IDX_NODE: index node
361  * UBIFS_CS_NODE: commit start node
362  * UBIFS_ORPH_NODE: orphan node
363  * UBIFS_AUTH_NODE: authentication node
364  * UBIFS_NODE_TYPES_CNT: count of supported node types
365  *
366  * Note, we index arrays by these numbers, so keep them low and contiguous.
367  * Node type constants for inodes, direntries and so on have to be the same as
368  * corresponding key type constants.
369  */
370 enum {
371 	UBIFS_INO_NODE,
372 	UBIFS_DATA_NODE,
373 	UBIFS_DENT_NODE,
374 	UBIFS_XENT_NODE,
375 	UBIFS_TRUN_NODE,
376 	UBIFS_PAD_NODE,
377 	UBIFS_SB_NODE,
378 	UBIFS_MST_NODE,
379 	UBIFS_REF_NODE,
380 	UBIFS_IDX_NODE,
381 	UBIFS_CS_NODE,
382 	UBIFS_ORPH_NODE,
383 	UBIFS_AUTH_NODE,
384 	UBIFS_NODE_TYPES_CNT,
385 };
386 
387 /*
388  * Master node flags.
389  *
390  * UBIFS_MST_DIRTY: rebooted uncleanly - master node is dirty
391  * UBIFS_MST_NO_ORPHS: no orphan inodes present
392  * UBIFS_MST_RCVRY: written by recovery
393  */
394 enum {
395 	UBIFS_MST_DIRTY = 1,
396 	UBIFS_MST_NO_ORPHS = 2,
397 	UBIFS_MST_RCVRY = 4,
398 };
399 
400 /*
401  * Node group type (used by recovery to recover whole group or none).
402  *
403  * UBIFS_NO_NODE_GROUP: this node is not part of a group
404  * UBIFS_IN_NODE_GROUP: this node is a part of a group
405  * UBIFS_LAST_OF_NODE_GROUP: this node is the last in a group
406  */
407 enum {
408 	UBIFS_NO_NODE_GROUP = 0,
409 	UBIFS_IN_NODE_GROUP,
410 	UBIFS_LAST_OF_NODE_GROUP,
411 };
412 
413 /*
414  * Superblock flags.
415  *
416  * UBIFS_FLG_BIGLPT: if "big" LPT model is used if set
417  * UBIFS_FLG_SPACE_FIXUP: first-mount "fixup" of free space within LEBs needed
418  * UBIFS_FLG_DOUBLE_HASH: store a 32bit cookie in directory entry nodes to
419  *			  support 64bit cookies for lookups by hash
420  * UBIFS_FLG_ENCRYPTION: this filesystem contains encrypted files
421  * UBIFS_FLG_AUTHENTICATION: this filesystem contains hashes for authentication
422  */
423 enum {
424 	UBIFS_FLG_BIGLPT = 0x02,
425 	UBIFS_FLG_SPACE_FIXUP = 0x04,
426 	UBIFS_FLG_DOUBLE_HASH = 0x08,
427 	UBIFS_FLG_ENCRYPTION = 0x10,
428 	UBIFS_FLG_AUTHENTICATION = 0x20,
429 };
430 
431 #define UBIFS_FLG_MASK (UBIFS_FLG_BIGLPT | UBIFS_FLG_SPACE_FIXUP | \
432 		UBIFS_FLG_DOUBLE_HASH | UBIFS_FLG_ENCRYPTION | \
433 		UBIFS_FLG_AUTHENTICATION)
434 
435 /**
436  * struct ubifs_ch - common header node.
437  * @magic: UBIFS node magic number (%UBIFS_NODE_MAGIC)
438  * @crc: CRC-32 checksum of the node header
439  * @sqnum: sequence number
440  * @len: full node length
441  * @node_type: node type
442  * @group_type: node group type
443  * @padding: reserved for future, zeroes
444  *
445  * Every UBIFS node starts with this common part. If the node has a key, the
446  * key always goes next.
447  */
448 struct ubifs_ch {
449 	__le32 magic;
450 	__le32 crc;
451 	__le64 sqnum;
452 	__le32 len;
453 	__u8 node_type;
454 	__u8 group_type;
455 	__u8 padding[2];
456 } __packed;
457 
458 /**
459  * union ubifs_dev_desc - device node descriptor.
460  * @new: new type device descriptor
461  * @huge: huge type device descriptor
462  *
463  * This data structure describes major/minor numbers of a device node. In an
464  * inode is a device node then its data contains an object of this type. UBIFS
465  * uses standard Linux "new" and "huge" device node encodings.
466  */
467 union ubifs_dev_desc {
468 	__le32 new;
469 	__le64 huge;
470 } __packed;
471 
472 /**
473  * struct ubifs_ino_node - inode node.
474  * @ch: common header
475  * @key: node key
476  * @creat_sqnum: sequence number at time of creation
477  * @size: inode size in bytes (amount of uncompressed data)
478  * @atime_sec: access time seconds
479  * @ctime_sec: creation time seconds
480  * @mtime_sec: modification time seconds
481  * @atime_nsec: access time nanoseconds
482  * @ctime_nsec: creation time nanoseconds
483  * @mtime_nsec: modification time nanoseconds
484  * @nlink: number of hard links
485  * @uid: owner ID
486  * @gid: group ID
487  * @mode: access flags
488  * @flags: per-inode flags (%UBIFS_COMPR_FL, %UBIFS_SYNC_FL, etc)
489  * @data_len: inode data length
490  * @xattr_cnt: count of extended attributes this inode has
491  * @xattr_size: summarized size of all extended attributes in bytes
492  * @padding1: reserved for future, zeroes
493  * @xattr_names: sum of lengths of all extended attribute names belonging to
494  *               this inode
495  * @compr_type: compression type used for this inode
496  * @padding2: reserved for future, zeroes
497  * @data: data attached to the inode
498  *
499  * Note, even though inode compression type is defined by @compr_type, some
500  * nodes of this inode may be compressed with different compressor - this
501  * happens if compression type is changed while the inode already has data
502  * nodes. But @compr_type will be use for further writes to the inode.
503  *
504  * Note, do not forget to amend 'zero_ino_node_unused()' function when changing
505  * the padding fields.
506  */
507 struct ubifs_ino_node {
508 	struct ubifs_ch ch;
509 	__u8 key[UBIFS_MAX_KEY_LEN];
510 	__le64 creat_sqnum;
511 	__le64 size;
512 	__le64 atime_sec;
513 	__le64 ctime_sec;
514 	__le64 mtime_sec;
515 	__le32 atime_nsec;
516 	__le32 ctime_nsec;
517 	__le32 mtime_nsec;
518 	__le32 nlink;
519 	__le32 uid;
520 	__le32 gid;
521 	__le32 mode;
522 	__le32 flags;
523 	__le32 data_len;
524 	__le32 xattr_cnt;
525 	__le32 xattr_size;
526 	__u8 padding1[4]; /* Watch 'zero_ino_node_unused()' if changing! */
527 	__le32 xattr_names;
528 	__le16 compr_type;
529 	__u8 padding2[26]; /* Watch 'zero_ino_node_unused()' if changing! */
530 	__u8 data[];
531 } __packed;
532 
533 /**
534  * struct ubifs_dent_node - directory entry node.
535  * @ch: common header
536  * @key: node key
537  * @inum: target inode number
538  * @padding1: reserved for future, zeroes
539  * @type: type of the target inode (%UBIFS_ITYPE_REG, %UBIFS_ITYPE_DIR, etc)
540  * @nlen: name length
541  * @cookie: A 32bits random number, used to construct a 64bits
542  *          identifier.
543  * @name: zero-terminated name
544  *
545  * Note, do not forget to amend 'zero_dent_node_unused()' function when
546  * changing the padding fields.
547  */
548 struct ubifs_dent_node {
549 	struct ubifs_ch ch;
550 	__u8 key[UBIFS_MAX_KEY_LEN];
551 	__le64 inum;
552 	__u8 padding1;
553 	__u8 type;
554 	__le16 nlen;
555 	__le32 cookie;
556 	__u8 name[];
557 } __packed;
558 
559 /**
560  * struct ubifs_data_node - data node.
561  * @ch: common header
562  * @key: node key
563  * @size: uncompressed data size in bytes
564  * @compr_type: compression type (%UBIFS_COMPR_NONE, %UBIFS_COMPR_LZO, etc)
565  * @compr_size: compressed data size in bytes, only valid when data is encrypted
566  * @data: data
567  *
568  */
569 struct ubifs_data_node {
570 	struct ubifs_ch ch;
571 	__u8 key[UBIFS_MAX_KEY_LEN];
572 	__le32 size;
573 	__le16 compr_type;
574 	__le16 compr_size;
575 	__u8 data[];
576 } __packed;
577 
578 /**
579  * struct ubifs_trun_node - truncation node.
580  * @ch: common header
581  * @inum: truncated inode number
582  * @padding: reserved for future, zeroes
583  * @old_size: size before truncation
584  * @new_size: size after truncation
585  *
586  * This node exists only in the journal and never goes to the main area. Note,
587  * do not forget to amend 'zero_trun_node_unused()' function when changing the
588  * padding fields.
589  */
590 struct ubifs_trun_node {
591 	struct ubifs_ch ch;
592 	__le32 inum;
593 	__u8 padding[12]; /* Watch 'zero_trun_node_unused()' if changing! */
594 	__le64 old_size;
595 	__le64 new_size;
596 } __packed;
597 
598 /**
599  * struct ubifs_pad_node - padding node.
600  * @ch: common header
601  * @pad_len: how many bytes after this node are unused (because padded)
602  * @padding: reserved for future, zeroes
603  */
604 struct ubifs_pad_node {
605 	struct ubifs_ch ch;
606 	__le32 pad_len;
607 } __packed;
608 
609 /**
610  * struct ubifs_sb_node - superblock node.
611  * @ch: common header
612  * @padding: reserved for future, zeroes
613  * @key_hash: type of hash function used in keys
614  * @key_fmt: format of the key
615  * @flags: file-system flags (%UBIFS_FLG_BIGLPT, etc)
616  * @min_io_size: minimal input/output unit size
617  * @leb_size: logical eraseblock size in bytes
618  * @leb_cnt: count of LEBs used by file-system
619  * @max_leb_cnt: maximum count of LEBs used by file-system
620  * @max_bud_bytes: maximum amount of data stored in buds
621  * @log_lebs: log size in logical eraseblocks
622  * @lpt_lebs: number of LEBs used for lprops table
623  * @orph_lebs: number of LEBs used for recording orphans
624  * @jhead_cnt: count of journal heads
625  * @fanout: tree fanout (max. number of links per indexing node)
626  * @lsave_cnt: number of LEB numbers in LPT's save table
627  * @fmt_version: UBIFS on-flash format version
628  * @default_compr: default compression algorithm (%UBIFS_COMPR_LZO, etc)
629  * @padding1: reserved for future, zeroes
630  * @rp_uid: reserve pool UID
631  * @rp_gid: reserve pool GID
632  * @rp_size: size of the reserved pool in bytes
633  * @padding2: reserved for future, zeroes
634  * @time_gran: time granularity in nanoseconds
635  * @uuid: UUID generated when the file system image was created
636  * @ro_compat_version: UBIFS R/O compatibility version
637  * @hmac: HMAC to authenticate the superblock node
638  * @hmac_wkm: HMAC of a well known message (the string "UBIFS") as a convenience
639  *            to the user to check if the correct key is passed.
640  * @hash_algo: The hash algo used for this filesystem (one of enum hash_algo)
641  */
642 struct ubifs_sb_node {
643 	struct ubifs_ch ch;
644 	__u8 padding[2];
645 	__u8 key_hash;
646 	__u8 key_fmt;
647 	__le32 flags;
648 	__le32 min_io_size;
649 	__le32 leb_size;
650 	__le32 leb_cnt;
651 	__le32 max_leb_cnt;
652 	__le64 max_bud_bytes;
653 	__le32 log_lebs;
654 	__le32 lpt_lebs;
655 	__le32 orph_lebs;
656 	__le32 jhead_cnt;
657 	__le32 fanout;
658 	__le32 lsave_cnt;
659 	__le32 fmt_version;
660 	__le16 default_compr;
661 	__u8 padding1[2];
662 	__le32 rp_uid;
663 	__le32 rp_gid;
664 	__le64 rp_size;
665 	__le32 time_gran;
666 	__u8 uuid[16];
667 	__le32 ro_compat_version;
668 	__u8 hmac[UBIFS_MAX_HMAC_LEN];
669 	__u8 hmac_wkm[UBIFS_MAX_HMAC_LEN];
670 	__le16 hash_algo;
671 	__u8 padding2[3838];
672 } __packed;
673 
674 /**
675  * struct ubifs_mst_node - master node.
676  * @ch: common header
677  * @highest_inum: highest inode number in the committed index
678  * @cmt_no: commit number
679  * @flags: various flags (%UBIFS_MST_DIRTY, etc)
680  * @log_lnum: start of the log
681  * @root_lnum: LEB number of the root indexing node
682  * @root_offs: offset within @root_lnum
683  * @root_len: root indexing node length
684  * @gc_lnum: LEB reserved for garbage collection (%-1 value means the LEB was
685  * not reserved and should be reserved on mount)
686  * @ihead_lnum: LEB number of index head
687  * @ihead_offs: offset of index head
688  * @index_size: size of index on flash
689  * @total_free: total free space in bytes
690  * @total_dirty: total dirty space in bytes
691  * @total_used: total used space in bytes (includes only data LEBs)
692  * @total_dead: total dead space in bytes (includes only data LEBs)
693  * @total_dark: total dark space in bytes (includes only data LEBs)
694  * @lpt_lnum: LEB number of LPT root nnode
695  * @lpt_offs: offset of LPT root nnode
696  * @nhead_lnum: LEB number of LPT head
697  * @nhead_offs: offset of LPT head
698  * @ltab_lnum: LEB number of LPT's own lprops table
699  * @ltab_offs: offset of LPT's own lprops table
700  * @lsave_lnum: LEB number of LPT's save table (big model only)
701  * @lsave_offs: offset of LPT's save table (big model only)
702  * @lscan_lnum: LEB number of last LPT scan
703  * @empty_lebs: number of empty logical eraseblocks
704  * @idx_lebs: number of indexing logical eraseblocks
705  * @leb_cnt: count of LEBs used by file-system
706  * @hash_root_idx: the hash of the root index node
707  * @hash_lpt: the hash of the LPT
708  * @hmac: HMAC to authenticate the master node
709  * @padding: reserved for future, zeroes
710  */
711 struct ubifs_mst_node {
712 	struct ubifs_ch ch;
713 	__le64 highest_inum;
714 	__le64 cmt_no;
715 	__le32 flags;
716 	__le32 log_lnum;
717 	__le32 root_lnum;
718 	__le32 root_offs;
719 	__le32 root_len;
720 	__le32 gc_lnum;
721 	__le32 ihead_lnum;
722 	__le32 ihead_offs;
723 	__le64 index_size;
724 	__le64 total_free;
725 	__le64 total_dirty;
726 	__le64 total_used;
727 	__le64 total_dead;
728 	__le64 total_dark;
729 	__le32 lpt_lnum;
730 	__le32 lpt_offs;
731 	__le32 nhead_lnum;
732 	__le32 nhead_offs;
733 	__le32 ltab_lnum;
734 	__le32 ltab_offs;
735 	__le32 lsave_lnum;
736 	__le32 lsave_offs;
737 	__le32 lscan_lnum;
738 	__le32 empty_lebs;
739 	__le32 idx_lebs;
740 	__le32 leb_cnt;
741 	__u8 hash_root_idx[UBIFS_MAX_HASH_LEN];
742 	__u8 hash_lpt[UBIFS_MAX_HASH_LEN];
743 	__u8 hmac[UBIFS_MAX_HMAC_LEN];
744 	__u8 padding[152];
745 } __packed;
746 
747 /**
748  * struct ubifs_ref_node - logical eraseblock reference node.
749  * @ch: common header
750  * @lnum: the referred logical eraseblock number
751  * @offs: start offset in the referred LEB
752  * @jhead: journal head number
753  * @padding: reserved for future, zeroes
754  */
755 struct ubifs_ref_node {
756 	struct ubifs_ch ch;
757 	__le32 lnum;
758 	__le32 offs;
759 	__le32 jhead;
760 	__u8 padding[28];
761 } __packed;
762 
763 /**
764  * struct ubifs_auth_node - node for authenticating other nodes
765  * @ch: common header
766  * @hmac: The HMAC
767  */
768 struct ubifs_auth_node {
769 	struct ubifs_ch ch;
770 	__u8 hmac[];
771 } __packed;
772 
773 /**
774  * struct ubifs_branch - key/reference/length branch
775  * @lnum: LEB number of the target node
776  * @offs: offset within @lnum
777  * @len: target node length
778  * @key: key
779  *
780  * In an authenticated UBIFS we have the hash of the referenced node after @key.
781  * This can't be added to the struct type definition because @key is a
782  * dynamically sized element already.
783  */
784 struct ubifs_branch {
785 	__le32 lnum;
786 	__le32 offs;
787 	__le32 len;
788 	__u8 key[];
789 } __packed;
790 
791 /**
792  * struct ubifs_idx_node - indexing node.
793  * @ch: common header
794  * @child_cnt: number of child index nodes
795  * @level: tree level
796  * @branches: LEB number / offset / length / key branches
797  */
798 struct ubifs_idx_node {
799 	struct ubifs_ch ch;
800 	__le16 child_cnt;
801 	__le16 level;
802 	__u8 branches[];
803 } __packed;
804 
805 /**
806  * struct ubifs_cs_node - commit start node.
807  * @ch: common header
808  * @cmt_no: commit number
809  */
810 struct ubifs_cs_node {
811 	struct ubifs_ch ch;
812 	__le64 cmt_no;
813 } __packed;
814 
815 /**
816  * struct ubifs_orph_node - orphan node.
817  * @ch: common header
818  * @cmt_no: commit number (also top bit is set on the last node of the commit)
819  * @inos: inode numbers of orphans
820  */
821 struct ubifs_orph_node {
822 	struct ubifs_ch ch;
823 	__le64 cmt_no;
824 	__le64 inos[];
825 } __packed;
826 
827 #endif /* __UBIFS_MEDIA_H__ */
828