kern/include/ext2fs.h

   1 /* Copyright (c) 2010 The Regents of the University of California
   2  * Barret Rhoden <brho@cs.berkeley.edu>
   3  * See LICENSE for details.
   4  *
   5  * The ROS port for Ext2 FS.  Thanks to Dave Poirier for maintaining this great
   6  * documentation: http://www.nongnu.org/ext2-doc/ext2.html and the ext group
   7  * that wrote the FS in the first place.
   8  *
   9  * Note all of ext2's disk structures are little-endian. */
  10
  11 #ifndef ROS_KERN_EXT2FS_H
  12 #define ROS_KERN_EXT2FS_H
  13
  14 #include <ros/common.h>
  15 #include <vfs.h>
  16 #include <endian.h>
  17
  18 #define EXT2_SUPER_MAGIC                0xef53
  19
  20 /* State settings */
  21 #define EXT2_VALID_FS                   1               /* Cleanly unmounted */
  22 #define EXT2_ERROR_FS                   2               /* Currently mounted / not unmounted */
  23
  24 /* s_error options */
  25 #define EXT2_ERRORS_CONTINUE    1               /* continue on error */
  26 #define EXT2_ERRORS_RO                  2               /* remount read-only */
  27 #define EXT2_ERRORS_PANIC               3               /* panic on error */
  28
  29 /* Creator OS options */
  30 #define EXT2_OS_LINUX                   0
  31 #define EXT2_OS_HURD                    1
  32 #define EXT2_OS_MASIX                   2
  33 #define EXT2_OS_FREEBSD                 3
  34 #define EXT2_OS_LITES                   4
  35 #define EXT2_OS_ROS                             666             /* got dibs on the mark of the beast */
  36
  37 /* Revision Levels */
  38 #define EXT2_GOOD_OLD_REV               0               /* Revision 0 */
  39 #define EXT2_DYNAMIC_REV                1               /* Revision 1, extra crazies, etc */
  40
  41 /* FS Compatibile Features.  We can support them or now, without risk of
  42  * damaging meta-data. */
  43 #define EXT2_FEATURE_COMPAT_DIR_PREALLOC        0x0001  /* block prealloc */
  44 #define EXT2_FEATURE_COMPAT_MAGIC_INODES        0x0002
  45 #define EXT2_FEATURE_COMPAT_HAS_JOURNAL         0x0004  /* ext3/4 journal */
  46 #define EXT2_FEATURE_COMPAT_EXT_ATTR            0x0008  /* extended inode attr */
  47 #define EXT2_FEATURE_COMPAT_RESIZE_INO          0x0010  /* non-standard ino size */
  48 #define EXT2_FEATURE_COMPAT_DIR_INDEX           0x0020  /* h-tree dir indexing */
  49
  50 /* FS Incompatibile Features.  We should refuse to mount if we don't support
  51  * any of these. */
  52 #define EXT2_FEATURE_INCOMPAT_COMPRESSION       0x0001  /* disk compression */
  53 #define EXT2_FEATURE_INCOMPAT_FILETYPE          0x0002
  54 #define EXT2_FEATURE_INCOMPAT_RECOVER           0x0004
  55 #define EXT2_FEATURE_INCOMPAT_JOURNAL_DEV       0x0008
  56 #define EXT2_FEATURE_INCOMPAT_META_BG           0x0010
  57
  58 /* FS read-only features: We should mount read-only if we don't support these */
  59 #define EXT2_FEATURE_RO_COMPAT_SPARSE_SUPER     0x0001  /* sparse superblock */
  60 #define EXT2_FEATURE_RO_COMPAT_LARGE_FILE       0x0002  /* 64-bit filesize */
  61 #define EXT2_FEATURE_RO_COMPAT_BTREE_DIR        0x0004  /* binary tree sorted dir */
  62
  63 /* Compression types (s_algo_bitmap) */
  64 #define EXT2_LZV1_ALG                   0x0001
  65 #define EXT2_LZRW3A_ALG                 0x0002
  66 #define EXT2_GZIP_ALG                   0x0004
  67 #define EXT2_BZIP2_ALG                  0x0008
  68 #define EXT2_LZO_ALG                    0x0010
  69
  70 /* Defined Reserved inodes */
  71 #define EXT2_BAD_INO                    1               /* bad blocks inode */
  72 #define EXT2_ROOT_INO                   2               /* root directory inode */
  73 #define EXT2_ACL_IDX_INO                3               /* ACL index (deprecated?) */
  74 #define EXT2_ACL_DATA_INO               4               /* ACL data (deprecated?) */
  75 #define EXT2_BOOT_LOADER_INO    5               /* boot loader inode */
  76 #define EXT2_UNDEL_DIR_INO              6               /* undelete directory inode */
  77
  78 /* Inode/File access mode and type (i_mode).  Note how they use hex here, but
  79 the crap we keep around for glibc/posix is (probably still) in octal. */
  80 #define EXT2_S_IFSOCK                   0xC000  /* socket */
  81 #define EXT2_S_IFLNK                    0xA000  /* symbolic link */
  82 #define EXT2_S_IFREG                    0x8000  /* regular file */
  83 #define EXT2_S_IFBLK                    0x6000  /* block device */
  84 #define EXT2_S_IFDIR                    0x4000  /* directory */
  85 #define EXT2_S_IFCHR                    0x2000  /* character device */
  86 #define EXT2_S_IFIFO                    0x1000  /* fifo */
  87 #define EXT2_S_ISUID                    0x0800  /* set process user id */
  88 #define EXT2_S_ISGID                    0x0400  /* set process group id */
  89 #define EXT2_S_ISVTX                    0x0200  /* sticky bit */
  90 #define EXT2_S_IRUSR                    0x0100  /* user read */
  91 #define EXT2_S_IWUSR                    0x0080  /* user write */
  92 #define EXT2_S_IXUSR                    0x0040  /* user execute */
  93 #define EXT2_S_IRGRP                    0x0020  /* group read */
  94 #define EXT2_S_IWGRP                    0x0010  /* group write */
  95 #define EXT2_S_IXGRP                    0x0008  /* group execute */
  96 #define EXT2_S_IROTH                    0x0004  /* others read */
  97 #define EXT2_S_IWOTH                    0x0002  /* others write */
  98 #define EXT2_S_IXOTH                    0x0001  /* others execute */
  99
 100 /* Inode flags, for how to access data for an inode/file/object */
 101 #define EXT2_SECRM_FL                   0x00000001      /* secure deletion */
 102 #define EXT2_UNRM_FL                    0x00000002      /* record for undelete */
 103 #define EXT2_COMPR_FL                   0x00000004      /* compressed file */
 104 #define EXT2_SYNC_FL                    0x00000008      /* synchronous updates */
 105 #define EXT2_IMMUTABLE_FL               0x00000010      /* immutable file */
 106 #define EXT2_APPEND_FL                  0x00000020      /* append only */
 107 #define EXT2_NODUMP_FL                  0x00000040      /* do not dump/delete file */
 108 #define EXT2_NOATIME_FL                 0x00000080      /* do not update i_atime */
 109 /* Compression Flags */
 110 #define EXT2_DIRTY_FL                   0x00000100      /* dirty (modified) */
 111 #define EXT2_COMPRBLK_FL                0x00000200      /* compressed blocks */
 112 #define EXT2_NOCOMPR_FL                 0x00000400      /* access raw compressed data */
 113 #define EXT2_ECOMPR_FL                  0x00000800      /* compression error */
 114 /* End of compression flags */
 115 #define EXT2_BTREE_FL                   0x00010000      /* b-tree format directory */
 116 #define EXT2_INDEX_FL                   0x00010000      /* hash indexed directory */
 117 #define EXT2_IMAGIC_FL                  0x00020000      /* AFS directory */
 118 #define EXT3_JOURNAL_DATA_FL    0x00040000      /* journal file data */
 119 #define EXT2_RESERVED_FL                0x80000000      /* reserved for ext2 library */
 120
 121 /* Directory entry file types */
 122 #define EXT2_FT_UNKNOWN                 0       /* unknown file type */
 123 #define EXT2_FT_REG_FILE                1       /* regular file */
 124 #define EXT2_FT_DIR                             2       /* directory */
 125 #define EXT2_FT_CHRDEV                  3       /* character device */
 126 #define EXT2_FT_BLKDEV                  4       /* block device */
 127 #define EXT2_FT_FIFO                    5       /* FIFO / buffer file */
 128 #define EXT2_FT_SOCK                    6       /* socket */
 129 #define EXT2_FT_SYMLINK                 7       /* symbolic link */
 130
 131 struct ext2_sb {
 132         uint32_t                                        s_inodes_cnt;           /* total, both used/free */
 133         uint32_t                                        s_blocks_cnt;           /* used/free/reserved */
 134         uint32_t                                        s_rblocks_cnt;          /* reserved for su/brho */
 135         uint32_t                                        s_free_blocks_cnt;      /* free, incl reserved */
 136         uint32_t                                        s_free_inodes_cnt;
 137         uint32_t                                        s_first_data_block;     /* id of block holding sb */
 138         uint32_t                                        s_log_block_size;
 139         uint32_t                                        s_log_frag_size;        /* no real frag support */
 140         uint32_t                                        s_blocks_per_group;
 141         uint32_t                                        s_frags_per_group;
 142         uint32_t                                        s_inodes_per_group;
 143         uint32_t                                        s_mtime;                        /* last mount time */
 144         uint32_t                                        s_wtime;                        /* last write to the FS */
 145         uint16_t                                        s_mnt_cnt;                      /* mounts since fsck */
 146         uint16_t                                        s_max_mnt_cnt;          /* mounts between fscks */
 147         uint16_t                                        s_magic;
 148         uint16_t                                        s_state;                        /* mount state */
 149         uint16_t                                        s_errors;                       /* what to do on error */
 150         uint16_t                                        s_minor_rev_level;
 151         uint32_t                                        s_lastcheck;            /* last fsck */
 152         uint32_t                                        s_checkinterval;        /* max time btw fscks */
 153         uint32_t                                        s_creator_os;
 154         uint32_t                                        s_rev_level;
 155         uint16_t                                        s_def_resuid;           /* uid for reserved blocks*/
 156         uint16_t                                        s_def_resgid;           /* gid for reserved blocks*/
 157 /* Next chunk, EXT2_DYNAMIC_REV specific */
 158         uint32_t                                        s_first_ino;            /* first usable for F_REG */
 159         uint16_t                                        s_inode_size;
 160         uint16_t                                        s_block_group_nr;       /* BG holding *this* SB */
 161         uint32_t                                        s_feature_compat;
 162         uint32_t                                        s_feature_incompat;
 163         uint32_t                                        s_feature_ro_compat;
 164         uint64_t                                        s_uuid[2];                      /* volume id */
 165         char                                            s_volume_name[16];      /* null terminated */
 166         char                                            s_last_mounted[64];     /* dir path of mount */
 167         uint32_t                                        s_algo_bitmap;          /* compression type */
 168 /* Next chunk, Performance Hints */
 169         uint8_t                                         s_prealloc_blocks;      /* when making F_REG */
 170         uint8_t                                         s_prealloc_dir_blocks;  /* when making F_DIR */
 171         uint16_t                                        s_padding1;
 172 /* Next chunk, Journaling Support */
 173         uint8_t                                         s_journal_uuid[16];
 174         uint32_t                                        s_journal_inum;         /* ino of the journal file*/
 175         uint32_t                                        s_journal_dev;          /* device num of journal */
 176         uint32_t                                        s_last_orphan;          /* first in list to delete*/
 177 /* Next chunk, Directory Indexing Support */
 178         uint32_t                                        s_hash_seed[4];         /* for directory indexing */
 179         uint8_t                                         s_def_hash_version;     /* default */
 180         uint8_t                                         s_padding2;
 181         uint16_t                                        s_padding3;
 182 /* Next chunk, Other options */
 183         uint32_t                                        s_default_mount_opts;
 184         uint32_t                                        s_first_meta_bg;        /* BG id of first meta */
 185         uint8_t                                         s_reserved[760];
 186 };
 187
 188 /* All block ids are absolute (not relative to the BG). */
 189 struct ext2_block_group {
 190         uint32_t                                        bg_block_bitmap;        /* block id of bitmap */
 191         uint32_t                                        bg_inode_bitmap;        /* block id of bitmap */
 192         uint32_t                                        bg_inode_table;         /* id of first block */
 193         uint16_t                                        bg_free_blocks_cnt;
 194         uint16_t                                        bg_free_inodes_cnt;
 195         uint16_t                                        bg_used_dirs_cnt;       /* inodes alloc to dirs */
 196         uint16_t                                        bg_padding;
 197         uint8_t                                         bg_reserved[12];
 198 };
 199
 200 /* Random note: expect some number of the initial inodes to be reserved (11 in
 201  * rev 0), and later versions just start from s_first_ino.
 202  *
 203  * Only regular files use the full 32bits of size.  Rev 0 uses a signed i_size.
 204  *
 205  * For the i_blocks, the first 12 are block numbers for direct blocks.  The
 206  * 13th entry ([12]) is the block number for the first indirect block.  The
 207  * 14th entry is the number for a doubly-indirect block, and the 15th is a
 208  * triply indirect block. Having a value of 0 in the array terminates it, with
 209  * no further blocks. (not clear how that works with holes)
 210  *
 211  * For the osd2[12], these should be unused for ext2, and they should be used
 212  * differently for ext4.
 213  *
 214  * Giant warning: the inode numbers start at 1 in the system, not 0! */
 215 struct ext2_inode {
 216         uint16_t                                        i_mode;                         /* file type and mode */
 217         uint16_t                                        i_uid;
 218         uint32_t                                        i_size;                         /* lower 32bits of size */
 219         uint32_t                                        i_atime;
 220         uint32_t                                        i_ctime;
 221         uint32_t                                        i_mtime;
 222         uint32_t                                        i_dtime;                        /* delete time */
 223         uint16_t                                        i_gid;
 224         uint16_t                                        i_links_cnt;            /* fs_ino->i_nlink */
 225         uint32_t                                        i_blocks;                       /* num blocks reserved */
 226         uint32_t                                        i_flags;                        /* how to access data */
 227         uint32_t                                        i_osd1;                         /* OS dependent */
 228         uint32_t                                        i_block[15];            /* list of blocks reserved*/
 229         uint32_t                                        i_generation;           /* used by NFS */
 230         uint32_t                                        i_file_acl;                     /* block num hold ext attr*/
 231         uint32_t                                        i_dir_acl;                      /* upper 32bits of size */
 232         uint32_t                                        i_faddr;                        /* fragment, obsolete. */
 233         uint8_t                                         i_osd2[12];                     /* OS dependent */
 234 };
 235
 236 /* a dir_inode of 0 means an unused entry.  reclen will go to the end of the
 237  * data block when it is the last entry.  These are 4-byte aligned on disk. */
 238 struct ext2_dirent {
 239         uint32_t                                        dir_inode;                      /* inode */
 240         uint16_t                                        dir_reclen;                     /* len, including padding */
 241         uint8_t                                         dir_namelen;            /* len of dir_name w/o \0 */
 242         uint8_t                                         dir_filetype;
 243         uint8_t                                         dir_name[256];          /* might be < 255 on disc */
 244 };
 245
 246 /* Every FS must extern it's type, and be included in vfs_init() */
 247 extern struct fs_type ext2_fs_type;
 248
 249 /* This hangs off the VFS's SB, and tracks in-memory copies of the disc SB and
 250  * the block group descriptor table.  For now, s_dirty (VFS) will track the
 251  * dirtiness of all things hanging off the sb.  Both of the objects contained
 252  * are kmalloc()d, as is this struct. */
 253 struct ext2_sb_info {
 254         struct ext2_sb                          *e2sb;
 255         struct ext2_block_group         *e2bg;
 256         unsigned int                            nr_bgs;
 257 };
 258
 259 /* Inode in-memory data.  This stuff is in cpu-native endianness.  If we start
 260  * using the data in the actual inode and in the buffer cache, change
 261  * ext2_my_bh() and its two callers.  Assume this data is dirty. */
 262 struct ext2_i_info {
 263         uint32_t                                        i_block[15];            /* list of blocks reserved*/
 264 };
 265 #endif /* ROS_KERN_EXT2FS_H */