2 * This file is part of UBIFS.
4 * Copyright (C) 2006-2008 Nokia Corporation.
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.
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
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
19 * Authors: Artem Bityutskiy (Битюцкий Артём)
24 * This file describes UBIFS on-flash format and contains definitions of all the
25 * relevant data structures and constants.
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).
33 #ifndef __UBIFS_MEDIA_H__
34 #define __UBIFS_MEDIA_H__
36 /* UBIFS node magic number (must not have the padding byte first or last) */
37 #define UBIFS_NODE_MAGIC 0x06101831
39 /* UBIFS on-flash format version */
40 #define UBIFS_FORMAT_VERSION 4
42 /* Minimum logical eraseblock size in bytes */
43 #define UBIFS_MIN_LEB_SZ (15*1024)
45 /* Initial CRC32 value used when calculating CRC checksums */
46 #define UBIFS_CRC32_INIT 0xFFFFFFFFU
49 * UBIFS does not try to compress data if its length is less than the below
52 #define UBIFS_MIN_COMPR_LEN 128
55 * If compressed data length is less than %UBIFS_MIN_COMPRESS_DIFF bytes
56 * shorter than uncompressed data length, UBIFS preferes to leave this data
57 * node uncompress, because it'll be read faster.
59 #define UBIFS_MIN_COMPRESS_DIFF 64
61 /* Root inode number */
62 #define UBIFS_ROOT_INO 1
64 /* Lowest inode number used for regular inodes (not UBIFS-only internal ones) */
65 #define UBIFS_FIRST_INO 64
68 * Maximum file name and extended attribute length (must be a multiple of 8,
71 #define UBIFS_MAX_NLEN 255
73 /* Maximum number of data journal heads */
74 #define UBIFS_MAX_JHEADS 1
77 * Size of UBIFS data block. Note, UBIFS is not a block oriented file-system,
78 * which means that it does not treat the underlying media as consisting of
79 * blocks like in case of hard drives. Do not be confused. UBIFS block is just
80 * the maximum amount of data which one data node can have or which can be
81 * attached to an inode node.
83 #define UBIFS_BLOCK_SIZE 4096
84 #define UBIFS_BLOCK_SHIFT 12
86 /* UBIFS padding byte pattern (must not be first or last byte of node magic) */
87 #define UBIFS_PADDING_BYTE 0xCE
89 /* Maximum possible key length */
90 #define UBIFS_MAX_KEY_LEN 16
92 /* Key length ("simple" format) */
93 #define UBIFS_SK_LEN 8
95 /* Minimum index tree fanout */
96 #define UBIFS_MIN_FANOUT 3
98 /* Maximum number of levels in UBIFS indexing B-tree */
99 #define UBIFS_MAX_LEVELS 512
101 /* Maximum amount of data attached to an inode in bytes */
102 #define UBIFS_MAX_INO_DATA UBIFS_BLOCK_SIZE
104 /* LEB Properties Tree fanout (must be power of 2) and fanout shift */
105 #define UBIFS_LPT_FANOUT 4
106 #define UBIFS_LPT_FANOUT_SHIFT 2
108 /* LEB Properties Tree bit field sizes */
109 #define UBIFS_LPT_CRC_BITS 16
110 #define UBIFS_LPT_CRC_BYTES 2
111 #define UBIFS_LPT_TYPE_BITS 4
113 /* The key is always at the same position in all keyed nodes */
114 #define UBIFS_KEY_OFFSET offsetof(struct ubifs_ino_node, key)
117 * LEB Properties Tree node types.
119 * UBIFS_LPT_PNODE: LPT leaf node (contains LEB properties)
120 * UBIFS_LPT_NNODE: LPT internal node
121 * UBIFS_LPT_LTAB: LPT's own lprops table
122 * UBIFS_LPT_LSAVE: LPT's save table (big model only)
123 * UBIFS_LPT_NODE_CNT: count of LPT node types
124 * UBIFS_LPT_NOT_A_NODE: all ones (15 for 4 bits) is never a valid node type
132 UBIFS_LPT_NOT_A_NODE = (1 << UBIFS_LPT_TYPE_BITS) - 1,
138 * UBIFS_ITYPE_REG: regular file
139 * UBIFS_ITYPE_DIR: directory
140 * UBIFS_ITYPE_LNK: soft link
141 * UBIFS_ITYPE_BLK: block device node
142 * UBIFS_ITYPE_CHR: character device node
143 * UBIFS_ITYPE_FIFO: fifo
144 * UBIFS_ITYPE_SOCK: socket
145 * UBIFS_ITYPES_CNT: count of supported file types
159 * Supported key hash functions.
161 * UBIFS_KEY_HASH_R5: R5 hash
162 * UBIFS_KEY_HASH_TEST: test hash which just returns first 4 bytes of the name
170 * Supported key formats.
172 * UBIFS_SIMPLE_KEY_FMT: simple key format
175 UBIFS_SIMPLE_KEY_FMT,
179 * The simple key format uses 29 bits for storing UBIFS block number and hash
182 #define UBIFS_S_KEY_BLOCK_BITS 29
183 #define UBIFS_S_KEY_BLOCK_MASK 0x1FFFFFFF
184 #define UBIFS_S_KEY_HASH_BITS UBIFS_S_KEY_BLOCK_BITS
185 #define UBIFS_S_KEY_HASH_MASK UBIFS_S_KEY_BLOCK_MASK
190 * UBIFS_INO_KEY: inode node key
191 * UBIFS_DATA_KEY: data node key
192 * UBIFS_DENT_KEY: directory entry node key
193 * UBIFS_XENT_KEY: extended attribute entry key
194 * UBIFS_KEY_TYPES_CNT: number of supported key types
204 /* Count of LEBs reserved for the superblock area */
205 #define UBIFS_SB_LEBS 1
206 /* Count of LEBs reserved for the master area */
207 #define UBIFS_MST_LEBS 2
209 /* First LEB of the superblock area */
210 #define UBIFS_SB_LNUM 0
211 /* First LEB of the master area */
212 #define UBIFS_MST_LNUM (UBIFS_SB_LNUM + UBIFS_SB_LEBS)
213 /* First LEB of the log area */
214 #define UBIFS_LOG_LNUM (UBIFS_MST_LNUM + UBIFS_MST_LEBS)
217 * The below constants define the absolute minimum values for various UBIFS
218 * media areas. Many of them actually depend of flash geometry and the FS
219 * configuration (number of journal heads, orphan LEBs, etc). This means that
220 * the smallest volume size which can be used for UBIFS cannot be pre-defined
221 * by these constants. The file-system that meets the below limitation will not
222 * necessarily mount. UBIFS does run-time calculations and validates the FS
226 /* Minimum number of logical eraseblocks in the log */
227 #define UBIFS_MIN_LOG_LEBS 2
228 /* Minimum number of bud logical eraseblocks (one for each head) */
229 #define UBIFS_MIN_BUD_LEBS 3
230 /* Minimum number of journal logical eraseblocks */
231 #define UBIFS_MIN_JNL_LEBS (UBIFS_MIN_LOG_LEBS + UBIFS_MIN_BUD_LEBS)
232 /* Minimum number of LPT area logical eraseblocks */
233 #define UBIFS_MIN_LPT_LEBS 2
234 /* Minimum number of orphan area logical eraseblocks */
235 #define UBIFS_MIN_ORPH_LEBS 1
237 * Minimum number of main area logical eraseblocks (buds, 3 for the index, 1
238 * for GC, 1 for deletions, and at least 1 for committed data).
240 #define UBIFS_MIN_MAIN_LEBS (UBIFS_MIN_BUD_LEBS + 6)
242 /* Minimum number of logical eraseblocks */
243 #define UBIFS_MIN_LEB_CNT (UBIFS_SB_LEBS + UBIFS_MST_LEBS + \
244 UBIFS_MIN_LOG_LEBS + UBIFS_MIN_LPT_LEBS + \
245 UBIFS_MIN_ORPH_LEBS + UBIFS_MIN_MAIN_LEBS)
247 /* Node sizes (N.B. these are guaranteed to be multiples of 8) */
248 #define UBIFS_CH_SZ sizeof(struct ubifs_ch)
249 #define UBIFS_INO_NODE_SZ sizeof(struct ubifs_ino_node)
250 #define UBIFS_DATA_NODE_SZ sizeof(struct ubifs_data_node)
251 #define UBIFS_DENT_NODE_SZ sizeof(struct ubifs_dent_node)
252 #define UBIFS_TRUN_NODE_SZ sizeof(struct ubifs_trun_node)
253 #define UBIFS_PAD_NODE_SZ sizeof(struct ubifs_pad_node)
254 #define UBIFS_SB_NODE_SZ sizeof(struct ubifs_sb_node)
255 #define UBIFS_MST_NODE_SZ sizeof(struct ubifs_mst_node)
256 #define UBIFS_REF_NODE_SZ sizeof(struct ubifs_ref_node)
257 #define UBIFS_IDX_NODE_SZ sizeof(struct ubifs_idx_node)
258 #define UBIFS_CS_NODE_SZ sizeof(struct ubifs_cs_node)
259 #define UBIFS_ORPH_NODE_SZ sizeof(struct ubifs_orph_node)
260 /* Extended attribute entry nodes are identical to directory entry nodes */
261 #define UBIFS_XENT_NODE_SZ UBIFS_DENT_NODE_SZ
262 /* Only this does not have to be multiple of 8 bytes */
263 #define UBIFS_BRANCH_SZ sizeof(struct ubifs_branch)
265 /* Maximum node sizes (N.B. these are guaranteed to be multiples of 8) */
266 #define UBIFS_MAX_DATA_NODE_SZ (UBIFS_DATA_NODE_SZ + UBIFS_BLOCK_SIZE)
267 #define UBIFS_MAX_INO_NODE_SZ (UBIFS_INO_NODE_SZ + UBIFS_MAX_INO_DATA)
268 #define UBIFS_MAX_DENT_NODE_SZ (UBIFS_DENT_NODE_SZ + UBIFS_MAX_NLEN + 1)
269 #define UBIFS_MAX_XENT_NODE_SZ UBIFS_MAX_DENT_NODE_SZ
271 /* The largest UBIFS node */
272 #define UBIFS_MAX_NODE_SZ UBIFS_MAX_INO_NODE_SZ
275 * On-flash inode flags.
277 * UBIFS_COMPR_FL: use compression for this inode
278 * UBIFS_SYNC_FL: I/O on this inode has to be synchronous
279 * UBIFS_IMMUTABLE_FL: inode is immutable
280 * UBIFS_APPEND_FL: writes to the inode may only append data
281 * UBIFS_DIRSYNC_FL: I/O on this directory inode has to be synchronous
282 * UBIFS_XATTR_FL: this inode is the inode for an extended attribute value
284 * Note, these are on-flash flags which correspond to ioctl flags
285 * (@FS_COMPR_FL, etc). They have the same values now, but generally, do not
286 * have to be the same.
289 UBIFS_COMPR_FL = 0x01,
290 UBIFS_SYNC_FL = 0x02,
291 UBIFS_IMMUTABLE_FL = 0x04,
292 UBIFS_APPEND_FL = 0x08,
293 UBIFS_DIRSYNC_FL = 0x10,
294 UBIFS_XATTR_FL = 0x20,
297 /* Inode flag bits used by UBIFS */
298 #define UBIFS_FL_MASK 0x0000001F
301 * UBIFS compression algorithms.
303 * UBIFS_COMPR_NONE: no compression
304 * UBIFS_COMPR_LZO: LZO compression
305 * UBIFS_COMPR_ZLIB: ZLIB compression
306 * UBIFS_COMPR_TYPES_CNT: count of supported compression types
312 UBIFS_COMPR_TYPES_CNT,
318 * UBIFS_INO_NODE: inode node
319 * UBIFS_DATA_NODE: data node
320 * UBIFS_DENT_NODE: directory entry node
321 * UBIFS_XENT_NODE: extended attribute node
322 * UBIFS_TRUN_NODE: truncation node
323 * UBIFS_PAD_NODE: padding node
324 * UBIFS_SB_NODE: superblock node
325 * UBIFS_MST_NODE: master node
326 * UBIFS_REF_NODE: LEB reference node
327 * UBIFS_IDX_NODE: index node
328 * UBIFS_CS_NODE: commit start node
329 * UBIFS_ORPH_NODE: orphan node
330 * UBIFS_NODE_TYPES_CNT: count of supported node types
332 * Note, we index arrays by these numbers, so keep them low and contiguous.
333 * Node type constants for inodes, direntries and so on have to be the same as
334 * corresponding key type constants.
349 UBIFS_NODE_TYPES_CNT,
355 * UBIFS_MST_DIRTY: rebooted uncleanly - master node is dirty
356 * UBIFS_MST_NO_ORPHS: no orphan inodes present
357 * UBIFS_MST_RCVRY: written by recovery
361 UBIFS_MST_NO_ORPHS = 2,
366 * Node group type (used by recovery to recover whole group or none).
368 * UBIFS_NO_NODE_GROUP: this node is not part of a group
369 * UBIFS_IN_NODE_GROUP: this node is a part of a group
370 * UBIFS_LAST_OF_NODE_GROUP: this node is the last in a group
373 UBIFS_NO_NODE_GROUP = 0,
375 UBIFS_LAST_OF_NODE_GROUP,
381 * UBIFS_FLG_BIGLPT: if "big" LPT model is used if set
384 UBIFS_FLG_BIGLPT = 0x02,
388 * struct ubifs_ch - common header node.
389 * @magic: UBIFS node magic number (%UBIFS_NODE_MAGIC)
390 * @crc: CRC-32 checksum of the node header
391 * @sqnum: sequence number
392 * @len: full node length
393 * @node_type: node type
394 * @group_type: node group type
395 * @padding: reserved for future, zeroes
397 * Every UBIFS node starts with this common part. If the node has a key, the
398 * key always goes next.
408 } __attribute__ ((packed));
411 * union ubifs_dev_desc - device node descriptor.
412 * @new: new type device descriptor
413 * @huge: huge type device descriptor
415 * This data structure describes major/minor numbers of a device node. In an
416 * inode is a device node then its data contains an object of this type. UBIFS
417 * uses standard Linux "new" and "huge" device node encodings.
419 union ubifs_dev_desc {
422 } __attribute__ ((packed));
425 * struct ubifs_ino_node - inode node.
428 * @creat_sqnum: sequence number at time of creation
429 * @size: inode size in bytes (amount of uncompressed data)
430 * @atime_sec: access time seconds
431 * @ctime_sec: creation time seconds
432 * @mtime_sec: modification time seconds
433 * @atime_nsec: access time nanoseconds
434 * @ctime_nsec: creation time nanoseconds
435 * @mtime_nsec: modification time nanoseconds
436 * @nlink: number of hard links
439 * @mode: access flags
440 * @flags: per-inode flags (%UBIFS_COMPR_FL, %UBIFS_SYNC_FL, etc)
441 * @data_len: inode data length
442 * @xattr_cnt: count of extended attributes this inode has
443 * @xattr_size: summarized size of all extended attributes in bytes
444 * @padding1: reserved for future, zeroes
445 * @xattr_names: sum of lengths of all extended attribute names belonging to
447 * @compr_type: compression type used for this inode
448 * @padding2: reserved for future, zeroes
449 * @data: data attached to the inode
451 * Note, even though inode compression type is defined by @compr_type, some
452 * nodes of this inode may be compressed with different compressor - this
453 * happens if compression type is changed while the inode already has data
454 * nodes. But @compr_type will be use for further writes to the inode.
456 * Note, do not forget to amend 'zero_ino_node_unused()' function when changing
457 * the padding fields.
459 struct ubifs_ino_node {
461 __u8 key[UBIFS_MAX_KEY_LEN];
478 __u8 padding1[4]; /* Watch 'zero_ino_node_unused()' if changing! */
481 __u8 padding2[26]; /* Watch 'zero_ino_node_unused()' if changing! */
483 } __attribute__ ((packed));
486 * struct ubifs_dent_node - directory entry node.
489 * @inum: target inode number
490 * @padding1: reserved for future, zeroes
491 * @type: type of the target inode (%UBIFS_ITYPE_REG, %UBIFS_ITYPE_DIR, etc)
493 * @padding2: reserved for future, zeroes
494 * @name: zero-terminated name
496 * Note, do not forget to amend 'zero_dent_node_unused()' function when
497 * changing the padding fields.
499 struct ubifs_dent_node {
501 __u8 key[UBIFS_MAX_KEY_LEN];
506 __u8 padding2[4]; /* Watch 'zero_dent_node_unused()' if changing! */
508 } __attribute__ ((packed));
511 * struct ubifs_data_node - data node.
514 * @size: uncompressed data size in bytes
515 * @compr_type: compression type (%UBIFS_COMPR_NONE, %UBIFS_COMPR_LZO, etc)
516 * @padding: reserved for future, zeroes
519 * Note, do not forget to amend 'zero_data_node_unused()' function when
520 * changing the padding fields.
522 struct ubifs_data_node {
524 __u8 key[UBIFS_MAX_KEY_LEN];
527 __u8 padding[2]; /* Watch 'zero_data_node_unused()' if changing! */
529 } __attribute__ ((packed));
532 * struct ubifs_trun_node - truncation node.
534 * @inum: truncated inode number
535 * @padding: reserved for future, zeroes
536 * @old_size: size before truncation
537 * @new_size: size after truncation
539 * This node exists only in the journal and never goes to the main area. Note,
540 * do not forget to amend 'zero_trun_node_unused()' function when changing the
543 struct ubifs_trun_node {
546 __u8 padding[12]; /* Watch 'zero_trun_node_unused()' if changing! */
549 } __attribute__ ((packed));
552 * struct ubifs_pad_node - padding node.
554 * @pad_len: how many bytes after this node are unused (because padded)
555 * @padding: reserved for future, zeroes
557 struct ubifs_pad_node {
560 } __attribute__ ((packed));
563 * struct ubifs_sb_node - superblock node.
565 * @padding: reserved for future, zeroes
566 * @key_hash: type of hash function used in keys
567 * @key_fmt: format of the key
568 * @flags: file-system flags (%UBIFS_FLG_BIGLPT, etc)
569 * @min_io_size: minimal input/output unit size
570 * @leb_size: logical eraseblock size in bytes
571 * @leb_cnt: count of LEBs used by file-system
572 * @max_leb_cnt: maximum count of LEBs used by file-system
573 * @max_bud_bytes: maximum amount of data stored in buds
574 * @log_lebs: log size in logical eraseblocks
575 * @lpt_lebs: number of LEBs used for lprops table
576 * @orph_lebs: number of LEBs used for recording orphans
577 * @jhead_cnt: count of journal heads
578 * @fanout: tree fanout (max. number of links per indexing node)
579 * @lsave_cnt: number of LEB numbers in LPT's save table
580 * @fmt_version: UBIFS on-flash format version
581 * @default_compr: default compression algorithm (%UBIFS_COMPR_LZO, etc)
582 * @padding1: reserved for future, zeroes
583 * @rp_uid: reserve pool UID
584 * @rp_gid: reserve pool GID
585 * @rp_size: size of the reserved pool in bytes
586 * @padding2: reserved for future, zeroes
587 * @time_gran: time granularity in nanoseconds
588 * @uuid: UUID generated when the file system image was created
590 struct ubifs_sb_node {
600 __le64 max_bud_bytes;
608 __le16 default_compr;
616 } __attribute__ ((packed));
619 * struct ubifs_mst_node - master node.
621 * @highest_inum: highest inode number in the committed index
622 * @cmt_no: commit number
623 * @flags: various flags (%UBIFS_MST_DIRTY, etc)
624 * @log_lnum: start of the log
625 * @root_lnum: LEB number of the root indexing node
626 * @root_offs: offset within @root_lnum
627 * @root_len: root indexing node length
628 * @gc_lnum: LEB reserved for garbage collection (%-1 value means the LEB was
629 * not reserved and should be reserved on mount)
630 * @ihead_lnum: LEB number of index head
631 * @ihead_offs: offset of index head
632 * @index_size: size of index on flash
633 * @total_free: total free space in bytes
634 * @total_dirty: total dirty space in bytes
635 * @total_used: total used space in bytes (includes only data LEBs)
636 * @total_dead: total dead space in bytes (includes only data LEBs)
637 * @total_dark: total dark space in bytes (includes only data LEBs)
638 * @lpt_lnum: LEB number of LPT root nnode
639 * @lpt_offs: offset of LPT root nnode
640 * @nhead_lnum: LEB number of LPT head
641 * @nhead_offs: offset of LPT head
642 * @ltab_lnum: LEB number of LPT's own lprops table
643 * @ltab_offs: offset of LPT's own lprops table
644 * @lsave_lnum: LEB number of LPT's save table (big model only)
645 * @lsave_offs: offset of LPT's save table (big model only)
646 * @lscan_lnum: LEB number of last LPT scan
647 * @empty_lebs: number of empty logical eraseblocks
648 * @idx_lebs: number of indexing logical eraseblocks
649 * @leb_cnt: count of LEBs used by file-system
650 * @padding: reserved for future, zeroes
652 struct ubifs_mst_node {
683 } __attribute__ ((packed));
686 * struct ubifs_ref_node - logical eraseblock reference node.
688 * @lnum: the referred logical eraseblock number
689 * @offs: start offset in the referred LEB
690 * @jhead: journal head number
691 * @padding: reserved for future, zeroes
693 struct ubifs_ref_node {
699 } __attribute__ ((packed));
702 * struct ubifs_branch - key/reference/length branch
703 * @lnum: LEB number of the target node
704 * @offs: offset within @lnum
705 * @len: target node length
708 struct ubifs_branch {
713 } __attribute__ ((packed));
716 * struct ubifs_idx_node - indexing node.
718 * @child_cnt: number of child index nodes
720 * @branches: LEB number / offset / length / key branches
722 struct ubifs_idx_node {
727 } __attribute__ ((packed));
730 * struct ubifs_cs_node - commit start node.
732 * @cmt_no: commit number
734 struct ubifs_cs_node {
737 } __attribute__ ((packed));
740 * struct ubifs_orph_node - orphan node.
742 * @cmt_no: commit number (also top bit is set on the last node of the commit)
743 * @inos: inode numbers of orphans
745 struct ubifs_orph_node {
749 } __attribute__ ((packed));
751 #endif /* __UBIFS_MEDIA_H__ */