summaryrefslogtreecommitdiff
path: root/fs/ubifs/ubifs-media.h
blob: 8b7c1844014ffbbeb1dcc93ce4be8dc1cbc65742 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
/*
 * This file is part of UBIFS.
 *
 * Copyright (C) 2006-2008 Nokia Corporation.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 as published by
 * the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 * more details.
 *
 * You should have received a copy of the GNU General Public License along with
 * this program; if not, write to the Free Software Foundation, Inc., 51
 * Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
 *
 * 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  0x06101831

/*
 * 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 5

/*
 * 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 0

/* Minimum logical eraseblock size in bytes */
#define UBIFS_MIN_LEB_SZ (15*1024)

/* Initial CRC32 value used when calculating CRC checksums */
#define UBIFS_CRC32_INIT 0xFFFFFFFFU

/*
 * UBIFS does not try to compress data if its length is less than the below
 * constant.
 */
#define UBIFS_MIN_COMPR_LEN 128

/*
 * 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 64

/* Root inode number */
#define UBIFS_ROOT_INO 1

/* Lowest inode number used for regular inodes (not UBIFS-only internal ones) */
#define UBIFS_FIRST_INO 64

/*
 * Maximum file name and extended attribute length (must be a multiple of 8,
 * minus 1).
 */
#define UBIFS_MAX_NLEN 255

/* Maximum number of data journal heads */
#define UBIFS_MAX_JHEADS 1

/*
 * 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  4096
#define UBIFS_BLOCK_SHIFT 12

/* UBIFS padding byte pattern (must not be first or last byte of node magic) */
#define UBIFS_PADDING_BYTE 0xCE

/* Maximum possible key length */
#define UBIFS_MAX_KEY_LEN 16

/* Key length ("simple" format) */
#define UBIFS_SK_LEN 8

/* Minimum index tree fanout */
#define UBIFS_MIN_FANOUT 3

/* Maximum number of levels in UBIFS indexing B-tree */
#define UBIFS_MAX_LEVELS 512

/* Maximum amount of data attached to an inode in bytes */
#define UBIFS_MAX_INO_DATA UBIFS_BLOCK_SIZE

/* LEB Properties Tree fanout (must be power of 2) and fanout shift */
#define UBIFS_LPT_FANOUT 4
#define UBIFS_LPT_FANOUT_SHIFT 2

/* LEB Properties Tree bit field sizes */
#define UBIFS_LPT_CRC_BITS 16
#define UBIFS_LPT_CRC_BYTES 2
#define UBIFS_LPT_TYPE_BITS 4

/* The key is always at the same position in all keyed nodes */
#define UBIFS_KEY_OFFSET offsetof(struct ubifs_ino_node, key)

/* Garbage collector journal head number */
#define UBIFS_GC_HEAD   0
/* Base journal head number */
#define UBIFS_BASE_HEAD 1
/* Data journal head number */
#define UBIFS_DATA_HEAD 2

/*
 * 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_LPT_PNODE,
	UBIFS_LPT_NNODE,
	UBIFS_LPT_LTAB,
	UBIFS_LPT_LSAVE,
	UBIFS_LPT_NODE_CNT,
	UBIFS_LPT_NOT_A_NODE = (1 << UBIFS_LPT_TYPE_BITS) - 1,
};

/*
 * 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 {
	UBIFS_ITYPE_REG,
	UBIFS_ITYPE_DIR,
	UBIFS_ITYPE_LNK,
	UBIFS_ITYPE_BLK,
	UBIFS_ITYPE_CHR,
	UBIFS_ITYPE_FIFO,
	UBIFS_ITYPE_SOCK,
	UBIFS_ITYPES_CNT,
};

/*
 * 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 {
	UBIFS_KEY_HASH_R5,
	UBIFS_KEY_HASH_TEST,
};

/*
 * Supported key formats.
 *
 * UBIFS_SIMPLE_KEY_FMT: simple key format
 */
enum {
	UBIFS_SIMPLE_KEY_FMT,
};

/*
 * The simple key format uses 29 bits for storing UBIFS block number and hash
 * value.
 */
#define UBIFS_S_KEY_BLOCK_BITS 29
#define UBIFS_S_KEY_BLOCK_MASK 0x1FFFFFFF
#define UBIFS_S_KEY_HASH_BITS  UBIFS_S_KEY_BLOCK_BITS
#define UBIFS_S_KEY_HASH_MASK  UBIFS_S_KEY_BLOCK_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 {
	UBIFS_INO_KEY,
	UBIFS_DATA_KEY,
	UBIFS_DENT_KEY,
	UBIFS_XENT_KEY,
	UBIFS_KEY_TYPES_CNT,
};

/* Count of LEBs reserved for the superblock area */
#define UBIFS_SB_LEBS 1
/* Count of LEBs reserved for the master area */
#define UBIFS_MST_LEBS 2

/* First LEB of the superblock area */
#define UBIFS_SB_LNUM 0
/* First LEB of the master area */
#define UBIFS_MST_LNUM (UBIFS_SB_LNUM + UBIFS_SB_LEBS)
/* First LEB of the log area */
#define UBIFS_LOG_LNUM (UBIFS_MST_LNUM + UBIFS_MST_LEBS)

/*
 * 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 2
/* Minimum number of bud logical eraseblocks (one for each head) */
#define UBIFS_MIN_BUD_LEBS 3
/* Minimum number of journal logical eraseblocks */
#define UBIFS_MIN_JNL_LEBS (UBIFS_MIN_LOG_LEBS + UBIFS_MIN_BUD_LEBS)
/* Minimum number of LPT area logical eraseblocks */
#define UBIFS_MIN_LPT_LEBS 2
/* Minimum number of orphan area logical eraseblocks */
#define UBIFS_MIN_ORPH_LEBS 1
/*
 * 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 (UBIFS_MIN_BUD_LEBS + 6)

/* Minimum number of logical eraseblocks */
#define UBIFS_MIN_LEB_CNT (UBIFS_SB_LEBS + UBIFS_MST_LEBS + \
			   UBIFS_MIN_LOG_LEBS + UBIFS_MIN_LPT_LEBS + \
			   UBIFS_MIN_ORPH_LEBS + UBIFS_MIN_MAIN_LEBS)

/* Node sizes (N.B. these are guaranteed to be multiples of 8) */
#define UBIFS_CH_SZ        sizeof(struct ubifs_ch)
#define UBIFS_INO_NODE_SZ  sizeof(struct ubifs_ino_node)
#define UBIFS_DATA_NODE_SZ sizeof(struct ubifs_data_node)
#define UBIFS_DENT_NODE_SZ sizeof(struct ubifs_dent_node)
#define UBIFS_TRUN_NODE_SZ sizeof(struct ubifs_trun_node)
#define UBIFS_PAD_NODE_SZ  sizeof(struct ubifs_pad_node)
#define UBIFS_SB_NODE_SZ   sizeof(struct ubifs_sb_node)
#define UBIFS_MST_NODE_SZ  sizeof(struct ubifs_mst_node)
#define UBIFS_REF_NODE_SZ  sizeof(struct ubifs_ref_node)
#define UBIFS_IDX_NODE_SZ  sizeof(struct ubifs_idx_node)
#define UBIFS_CS_NODE_SZ   sizeof(struct ubifs_cs_node)
#define UBIFS_ORPH_NODE_SZ sizeof(struct ubifs_orph_node)
#define UBIFS_AUTH_NODE_SZ sizeof(struct ubifs_auth_node)
/* Extended attribute entry nodes are identical to directory entry nodes */
#define UBIFS_XENT_NODE_SZ UBIFS_DENT_NODE_SZ
/* Only this does not have to be multiple of 8 bytes */
#define UBIFS_BRANCH_SZ    sizeof(struct ubifs_branch)

/* Maximum node sizes (N.B. these are guaranteed to be multiples of 8) */
#define UBIFS_MAX_DATA_NODE_SZ  (UBIFS_DATA_NODE_SZ + UBIFS_BLOCK_SIZE)
#define UBIFS_MAX_INO_NODE_SZ   (UBIFS_INO_NODE_SZ + UBIFS_MAX_INO_DATA)
#define UBIFS_MAX_DENT_NODE_SZ  (UBIFS_DENT_NODE_SZ + UBIFS_MAX_NLEN + 1)
#define UBIFS_MAX_XENT_NODE_SZ  UBIFS_MAX_DENT_NODE_SZ

/* The largest UBIFS node */
#define UBIFS_MAX_NODE_SZ UBIFS_MAX_INO_NODE_SZ

/* The maxmimum size of a hash, enough for sha512 */
#define UBIFS_MAX_HASH_LEN 64

/* The maxmimum size of a hmac, enough for hmac(sha512) */
#define UBIFS_MAX_HMAC_LEN 64

/*
 * 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 "c"


/*
 * 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 {
	UBIFS_COMPR_FL     = 0x01,
	UBIFS_SYNC_FL      = 0x02,
	UBIFS_IMMUTABLE_FL = 0x04,
	UBIFS_APPEND_FL    = 0x08,
	UBIFS_DIRSYNC_FL   = 0x10,
	UBIFS_XATTR_FL     = 0x20,
	UBIFS_CRYPT_FL     = 0x40,
};

/* Inode flag bits used by UBIFS */
#define UBIFS_FL_MASK 0x0000001F

/*
 * UBIFS compression algorithms.
 *
 * UBIFS_COMPR_NONE: no compression
 * UBIFS_COMPR_LZO: LZO compression
 * UBIFS_COMPR_ZLIB: ZLIB compression
 * UBIFS_COMPR_TYPES_CNT: count of supported compression types
 */
enum {
	UBIFS_COMPR_NONE,
	UBIFS_COMPR_LZO,
	UBIFS_COMPR_ZLIB,
	UBIFS_COMPR_TYPES_CNT,
};

/*
 * 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_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 {
	UBIFS_INO_NODE,
	UBIFS_DATA_NODE,
	UBIFS_DENT_NODE,
	UBIFS_XENT_NODE,
	UBIFS_TRUN_NODE,
	UBIFS_PAD_NODE,
	UBIFS_SB_NODE,
	UBIFS_MST_NODE,
	UBIFS_REF_NODE,
	UBIFS_IDX_NODE,
	UBIFS_CS_NODE,
	UBIFS_ORPH_NODE,
	UBIFS_AUTH_NODE,
	UBIFS_NODE_TYPES_CNT,
};

/*
 * 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 {
	UBIFS_MST_DIRTY = 1,
	UBIFS_MST_NO_ORPHS = 2,
	UBIFS_MST_RCVRY = 4,
};

/*
 * 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 {
	UBIFS_NO_NODE_GROUP = 0,
	UBIFS_IN_NODE_GROUP,
	UBIFS_LAST_OF_NODE_GROUP,
};

/*
 * 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 {
	UBIFS_FLG_BIGLPT = 0x02,
	UBIFS_FLG_SPACE_FIXUP = 0x04,
	UBIFS_FLG_DOUBLE_HASH = 0x08,
	UBIFS_FLG_ENCRYPTION = 0x10,
	UBIFS_FLG_AUTHENTICATION = 0x20,
};

#define UBIFS_FLG_MASK (UBIFS_FLG_BIGLPT | UBIFS_FLG_SPACE_FIXUP | \
		UBIFS_FLG_DOUBLE_HASH | UBIFS_FLG_ENCRYPTION | \
		UBIFS_FLG_AUTHENTICATION)

/**
 * 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 {
	__le32 magic;
	__le32 crc;
	__le64 sqnum;
	__le32 len;
	__u8 node_type;
	__u8 group_type;
	__u8 padding[2];
} __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.
 */
union ubifs_dev_desc {
	__le32 new;
	__le64 huge;
} __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 {
	struct ubifs_ch ch;
	__u8 key[UBIFS_MAX_KEY_LEN];
	__le64 creat_sqnum;
	__le64 size;
	__le64 atime_sec;
	__le64 ctime_sec;
	__le64 mtime_sec;
	__le32 atime_nsec;
	__le32 ctime_nsec;
	__le32 mtime_nsec;
	__le32 nlink;
	__le32 uid;
	__le32 gid;
	__le32 mode;
	__le32 flags;
	__le32 data_len;
	__le32 xattr_cnt;
	__le32 xattr_size;
	__u8 padding1[4]; /* Watch 'zero_ino_node_unused()' if changing! */
	__le32 xattr_names;
	__le16 compr_type;
	__u8 padding2[26]; /* Watch 'zero_ino_node_unused()' if changing! */
	__u8 data[];
} __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 {
	struct ubifs_ch ch;
	__u8 key[UBIFS_MAX_KEY_LEN];
	__le64 inum;
	__u8 padding1;
	__u8 type;
	__le16 nlen;
	__le32 cookie;
	__u8 name[];
} __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 {
	struct ubifs_ch ch;
	__u8 key[UBIFS_MAX_KEY_LEN];
	__le32 size;
	__le16 compr_type;
	__le16 compr_size;
	__u8 data[];
} __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 {
	struct ubifs_ch ch;
	__le32 inum;
	__u8 padding[12]; /* Watch 'zero_trun_node_unused()' if changing! */
	__le64 old_size;
	__le64 new_size;
} __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 {
	struct ubifs_ch ch;
	__le32 pad_len;
} __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)
 */
struct ubifs_sb_node {
	struct ubifs_ch ch;
	__u8 padding[2];
	__u8 key_hash;
	__u8 key_fmt;
	__le32 flags;
	__le32 min_io_size;
	__le32 leb_size;
	__le32 leb_cnt;
	__le32 max_leb_cnt;
	__le64 max_bud_bytes;
	__le32 log_lebs;
	__le32 lpt_lebs;
	__le32 orph_lebs;
	__le32 jhead_cnt;
	__le32 fanout;
	__le32 lsave_cnt;
	__le32 fmt_version;
	__le16 default_compr;
	__u8 padding1[2];
	__le32 rp_uid;
	__le32 rp_gid;
	__le64 rp_size;
	__le32 time_gran;
	__u8 uuid[16];
	__le32 ro_compat_version;
	__u8 hmac[UBIFS_MAX_HMAC_LEN];
	__u8 hmac_wkm[UBIFS_MAX_HMAC_LEN];
	__le16 hash_algo;
	__u8 padding2[3838];
} __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 {
	struct ubifs_ch ch;
	__le64 highest_inum;
	__le64 cmt_no;
	__le32 flags;
	__le32 log_lnum;
	__le32 root_lnum;
	__le32 root_offs;
	__le32 root_len;
	__le32 gc_lnum;
	__le32 ihead_lnum;
	__le32 ihead_offs;
	__le64 index_size;
	__le64 total_free;
	__le64 total_dirty;
	__le64 total_used;
	__le64 total_dead;
	__le64 total_dark;
	__le32 lpt_lnum;
	__le32 lpt_offs;
	__le32 nhead_lnum;
	__le32 nhead_offs;
	__le32 ltab_lnum;
	__le32 ltab_offs;
	__le32 lsave_lnum;
	__le32 lsave_offs;
	__le32 lscan_lnum;
	__le32 empty_lebs;
	__le32 idx_lebs;
	__le32 leb_cnt;
	__u8 hash_root_idx[UBIFS_MAX_HASH_LEN];
	__u8 hash_lpt[UBIFS_MAX_HASH_LEN];
	__u8 hmac[UBIFS_MAX_HMAC_LEN];
	__u8 padding[152];
} __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 {
	struct ubifs_ch ch;
	__le32 lnum;
	__le32 offs;
	__le32 jhead;
	__u8 padding[28];
} __packed;

/**
 * struct ubifs_auth_node - node for authenticating other nodes
 * @ch: common header
 * @hmac: The HMAC
 */
struct ubifs_auth_node {
	struct ubifs_ch ch;
	__u8 hmac[];
} __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 {
	__le32 lnum;
	__le32 offs;
	__le32 len;
	__u8 key[];
} __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 {
	struct ubifs_ch ch;
	__le16 child_cnt;
	__le16 level;
	__u8 branches[];
} __packed;

/**
 * struct ubifs_cs_node - commit start node.
 * @ch: common header
 * @cmt_no: commit number
 */
struct ubifs_cs_node {
	struct ubifs_ch ch;
	__le64 cmt_no;
} __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 {
	struct ubifs_ch ch;
	__le64 cmt_no;
	__le64 inos[];
} __packed;

#endif /* __UBIFS_MEDIA_H__ */