include/linux/jffs2.h

   1 /*
   2  * JFFS2 -- Journalling Flash File System, Version 2.
   3  *
   4  * Copyright (C) 2001-2003 Red Hat, Inc.
   5  *
   6  * Created by David Woodhouse <dwmw2@infradead.org>
   7  *
   8  * For licensing information, see the file 'LICENCE' in the
   9  * jffs2 directory.
  10  *
  11  * $Id: jffs2.h,v 1.38 2005/09/26 11:37:23 havasi Exp $
  12  *
  13  */
  14
  15 #ifndef __LINUX_JFFS2_H__
  16 #define __LINUX_JFFS2_H__
  17
  18 /* You must include something which defines the C99 uintXX_t types.
  19    We don't do it from here because this file is used in too many
  20    different environments. */
  21
  22 #define JFFS2_SUPER_MAGIC 0x72b6
  23
  24 /* Values we may expect to find in the 'magic' field */
  25 #define JFFS2_OLD_MAGIC_BITMASK 0x1984
  26 #define JFFS2_MAGIC_BITMASK 0x1985
  27 #define KSAMTIB_CIGAM_2SFFJ 0x8519 /* For detecting wrong-endian fs */
  28 #define JFFS2_EMPTY_BITMASK 0xffff
  29 #define JFFS2_DIRTY_BITMASK 0x0000
  30
  31 /* Summary node MAGIC marker */
  32 #define JFFS2_SUM_MAGIC 0x02851885
  33
  34 /* We only allow a single char for length, and 0xFF is empty flash so
  35    we don't want it confused with a real length. Hence max 254.
  36 */
  37 #define JFFS2_MAX_NAME_LEN 254
  38
  39 /* How small can we sensibly write nodes? */
  40 #define JFFS2_MIN_DATA_LEN 128
  41
  42 #define JFFS2_COMPR_NONE        0x00
  43 #define JFFS2_COMPR_ZERO        0x01
  44 #define JFFS2_COMPR_RTIME       0x02
  45 #define JFFS2_COMPR_RUBINMIPS   0x03
  46 #define JFFS2_COMPR_COPY        0x04
  47 #define JFFS2_COMPR_DYNRUBIN    0x05
  48 #define JFFS2_COMPR_ZLIB        0x06
  49 /* Compatibility flags. */
  50 #define JFFS2_COMPAT_MASK 0xc000      /* What do to if an unknown nodetype is found */
  51 #define JFFS2_NODE_ACCURATE 0x2000
  52 /* INCOMPAT: Fail to mount the filesystem */
  53 #define JFFS2_FEATURE_INCOMPAT 0xc000
  54 /* ROCOMPAT: Mount read-only */
  55 #define JFFS2_FEATURE_ROCOMPAT 0x8000
  56 /* RWCOMPAT_COPY: Mount read/write, and copy the node when it's GC'd */
  57 #define JFFS2_FEATURE_RWCOMPAT_COPY 0x4000
  58 /* RWCOMPAT_DELETE: Mount read/write, and delete the node when it's GC'd */
  59 #define JFFS2_FEATURE_RWCOMPAT_DELETE 0x0000
  60
  61 #define JFFS2_NODETYPE_DIRENT (JFFS2_FEATURE_INCOMPAT | JFFS2_NODE_ACCURATE | 1)
  62 #define JFFS2_NODETYPE_INODE (JFFS2_FEATURE_INCOMPAT | JFFS2_NODE_ACCURATE | 2)
  63 #define JFFS2_NODETYPE_CLEANMARKER (JFFS2_FEATURE_RWCOMPAT_DELETE | JFFS2_NODE_ACCURATE | 3)
  64 #define JFFS2_NODETYPE_PADDING (JFFS2_FEATURE_RWCOMPAT_DELETE | JFFS2_NODE_ACCURATE | 4)
  65
  66 #define JFFS2_NODETYPE_SUMMARY (JFFS2_FEATURE_RWCOMPAT_DELETE | JFFS2_NODE_ACCURATE | 6)
  67
  68 // Maybe later...
  69 //#define JFFS2_NODETYPE_CHECKPOINT (JFFS2_FEATURE_RWCOMPAT_DELETE | JFFS2_NODE_ACCURATE | 3)
  70 //#define JFFS2_NODETYPE_OPTIONS (JFFS2_FEATURE_RWCOMPAT_COPY | JFFS2_NODE_ACCURATE | 4)
  71
  72
  73 #define JFFS2_INO_FLAG_PREREAD    1     /* Do read_inode() for this one at
  74                                            mount time, don't wait for it to
  75                                            happen later */
  76 #define JFFS2_INO_FLAG_USERCOMPR  2     /* User has requested a specific
  77                                            compression type */
  78
  79
  80 /* These can go once we've made sure we've caught all uses without
  81    byteswapping */
  82
  83 typedef struct {
  84         uint32_t v32;
  85 } __attribute__((packed))  jint32_t;
  86
  87 typedef struct {
  88         uint32_t m;
  89 } __attribute__((packed))  jmode_t;
  90
  91 typedef struct {
  92         uint16_t v16;
  93 } __attribute__((packed)) jint16_t;
  94
  95 struct jffs2_unknown_node
  96 {
  97         /* All start like this */
  98         jint16_t magic;
  99         jint16_t nodetype;
 100         jint32_t totlen; /* So we can skip over nodes we don't grok */
 101         jint32_t hdr_crc;
 102 } __attribute__((packed));
 103
 104 struct jffs2_raw_dirent
 105 {
 106         jint16_t magic;
 107         jint16_t nodetype;      /* == JFFS2_NODETYPE_DIRENT */
 108         jint32_t totlen;
 109         jint32_t hdr_crc;
 110         jint32_t pino;
 111         jint32_t version;
 112         jint32_t ino; /* == zero for unlink */
 113         jint32_t mctime;
 114         uint8_t nsize;
 115         uint8_t type;
 116         uint8_t unused[2];
 117         jint32_t node_crc;
 118         jint32_t name_crc;
 119         uint8_t name[0];
 120 } __attribute__((packed));
 121
 122 /* The JFFS2 raw inode structure: Used for storage on physical media.  */
 123 /* The uid, gid, atime, mtime and ctime members could be longer, but
 124    are left like this for space efficiency. If and when people decide
 125    they really need them extended, it's simple enough to add support for
 126    a new type of raw node.
 127 */
 128 struct jffs2_raw_inode
 129 {
 130         jint16_t magic;      /* A constant magic number.  */
 131         jint16_t nodetype;   /* == JFFS2_NODETYPE_INODE */
 132         jint32_t totlen;     /* Total length of this node (inc data, etc.) */
 133         jint32_t hdr_crc;
 134         jint32_t ino;        /* Inode number.  */
 135         jint32_t version;    /* Version number.  */
 136         jmode_t mode;       /* The file's type or mode.  */
 137         jint16_t uid;        /* The file's owner.  */
 138         jint16_t gid;        /* The file's group.  */
 139         jint32_t isize;      /* Total resultant size of this inode (used for truncations)  */
 140         jint32_t atime;      /* Last access time.  */
 141         jint32_t mtime;      /* Last modification time.  */
 142         jint32_t ctime;      /* Change time.  */
 143         jint32_t offset;     /* Where to begin to write.  */
 144         jint32_t csize;      /* (Compressed) data size */
 145         jint32_t dsize;      /* Size of the node's data. (after decompression) */
 146         uint8_t compr;       /* Compression algorithm used */
 147         uint8_t usercompr;   /* Compression algorithm requested by the user */
 148         jint16_t flags;      /* See JFFS2_INO_FLAG_* */
 149         jint32_t data_crc;   /* CRC for the (compressed) data.  */
 150         jint32_t node_crc;   /* CRC for the raw inode (excluding data)  */
 151         uint8_t data[0];
 152 } __attribute__((packed));
 153
 154 struct jffs2_raw_summary
 155 {
 156         jint16_t magic;
 157         jint16_t nodetype;      /* = JFFS2_NODETYPE_SUMMARY */
 158         jint32_t totlen;
 159         jint32_t hdr_crc;
 160         jint32_t sum_num;       /* number of sum entries*/
 161         jint32_t cln_mkr;       /* clean marker size, 0 = no cleanmarker */
 162         jint32_t padded;        /* sum of the size of padding nodes */
 163         jint32_t sum_crc;       /* summary information crc */
 164         jint32_t node_crc;      /* node crc */
 165         jint32_t sum[0];        /* inode summary info */
 166 } __attribute__((packed));
 167
 168 union jffs2_node_union
 169 {
 170         struct jffs2_raw_inode i;
 171         struct jffs2_raw_dirent d;
 172         struct jffs2_raw_summary s;
 173         struct jffs2_unknown_node u;
 174 };
 175
 176 #endif /* __LINUX_JFFS2_H__ */