core/fs/ext2/ext2_fs.h

   1 #ifndef __EXT2_FS_H
   2 #define __EXT2_FS_H
   3
   4 #include <stdint.h>
   5
   6 #define EXT2_SUPER_MAGIC        0xEF53
   7
   8 #define EXT2_GOOD_OLD_REV       0       // The good old (original) format
   9 #define EXT2_DYNAMIC_REV        1       // V2 format w/ dynamic inode sizes
  10 #define EXT2_GOOD_OLD_INODE_SIZE 128
  11
  12 // Special inode numbers
  13 #define EXT2_BAD_INO             1      // Bad blocks inode
  14 #define EXT2_ROOT_INO            2      // Root inode
  15 #define EXT2_BOOT_LOADER_INO     5      // Boot loader inode
  16 #define EXT2_UNDEL_DIR_INO       6      // Undelete directory inode
  17 #define EXT3_RESIZE_INO          7      // Reserved group descriptors inode
  18 #define EXT3_JOURNAL_INO         8      // Journal inode
  19
  20 // We're readonly, so we only care about incompat features.
  21 #define EXT2_FEATURE_INCOMPAT_COMPRESSION       0x0001
  22 #define EXT2_FEATURE_INCOMPAT_FILETYPE          0x0002
  23 #define EXT3_FEATURE_INCOMPAT_RECOVER           0x0004
  24 #define EXT3_FEATURE_INCOMPAT_JOURNAL_DEV       0x0008
  25 #define EXT2_FEATURE_INCOMPAT_META_BG           0x0010
  26 #define EXT2_FEATURE_INCOMPAT_ANY               0xffffffff
  27
  28 #define EXT2_NDIR_BLOCKS        12
  29 #define EXT2_IND_BLOCK          EXT2_NDIR_BLOCKS
  30 #define EXT2_DIND_BLOCK         (EXT2_IND_BLOCK+1)
  31 #define EXT2_TIND_BLOCK         (EXT2_DIND_BLOCK+1)
  32 #define EXT2_N_BLOCKS           (EXT2_TIND_BLOCK+1)
  33
  34
  35 /* for EXT4 extent */
  36 #define EXT4_EXT_MAGIC     0xf30a
  37 #define EXT4_EXTENTS_FLAG  0x00080000
  38
  39 /*
  40  * File types and file modes
  41  */
  42 #define S_IFDIR         0040000         // Directory
  43 #define S_IFCHR         0020000         // Character device
  44 #define S_IFBLK         0060000         // Block device
  45 #define S_IFREG         0100000         // Regular file
  46 #define S_IFIFO         0010000         // FIFO
  47 #define S_IFLNK         0120000         // Symbolic link
  48 #define S_IFSOCK        0140000         // Socket
  49
  50 #define S_IFSHIFT       12
  51
  52 #define T_IFDIR         (S_IFDIR >> S_IFSHIFT)
  53 #define T_IFCHR         (S_IFCHR >> S_IFSHIFT)
  54 #define T_IFBLK         (S_IFBLK >> S_IFSHIFT)
  55 #define T_IFREG         (S_IFREG >> S_IFSHIFT)
  56 #define T_IFIFO         (S_IFIFO >> S_IFSHIFT)
  57 #define T_IFLNK         (S_IFLNK >> S_IFSHIFT)
  58 #define T_IFSOCK        (S_IFSOCK >> S_IFSHIFT)
  59
  60
  61 #define ext2_group_desc_lg2size 5
  62
  63
  64
  65 /*
  66  * super block structure:
  67  * include/linux/ext2_fs.h
  68  */
  69 struct ext2_super_block {
  70     uint32_t s_inodes_count;            /* Inodes count */
  71     uint32_t s_blocks_count;            /* Blocks count */
  72     uint32_t s_r_blocks_count;          /* Reserved blocks count */
  73     uint32_t s_free_blocks_count;       /* Free blocks count */
  74     uint32_t s_free_inodes_count;       /* Free inodes count */
  75     uint32_t s_first_data_block;        /* First Data Block */
  76     uint32_t s_log_block_size;          /* Block size */
  77     uint32_t s_log_frag_size;           /* Fragment size */
  78     uint32_t s_blocks_per_group;        /* # Blocks per group */
  79     uint32_t s_frags_per_group;         /* # Fragments per group */
  80     uint32_t s_inodes_per_group;        /* # Inodes per group */
  81     uint32_t s_mtime;                   /* Mount time */
  82     uint32_t s_wtime;                   /* Write time */
  83     uint16_t s_mnt_count;               /* Mount count */
  84     int16_t  s_max_mnt_count;           /* Maximal mount count */
  85     uint16_t s_magic;                   /* Magic signature */
  86     uint16_t s_state;                   /* File system state */
  87     uint16_t s_errors;                  /* Behaviour when detecting errors */
  88     uint16_t s_minor_rev_level;
  89     uint32_t s_lastcheck;               /* time of last check */
  90     uint32_t s_checkinterval;           /* max. time between checks */
  91     uint32_t s_creator_os;              /* OS */
  92     uint32_t s_rev_level;               /* Revision level */
  93     uint16_t s_def_resuid;              /* Default uid for reserved blocks */
  94     uint16_t s_def_resgid;              /* Default gid for reserved blocks */
  95
  96     uint32_t s_first_ino;               /* First non-reserved inode */
  97     uint16_t s_inode_size;              /* size of inode structure */
  98     uint16_t s_block_group_nr;          /* block group # of this superblock */
  99     uint32_t s_feature_compat;          /* compatible feature set */
 100     uint32_t s_feature_incompat;        /* incompatible feature set */
 101     uint32_t s_feature_ro_compat;       /* readonly-compatible feature set */
 102     uint8_t  s_uuid[16];                /* 128-bit uuid for volume */
 103     char  s_volume_name[16];            /* volume name */
 104     char  s_last_mounted[64];           /* directory where last mounted */
 105     uint32_t s_algorithm_usage_bitmap;  /* For compression */
 106     uint8_t  s_prealloc_blocks;         /* Nr of blocks to try to preallocate*/
 107     uint8_t  s_prealloc_dir_blocks;
 108     uint16_t s_reserved_gdt_blocks;     /* Per group desc for online growth */
 109     /*
 110      * Journaling support valid if EXT4_FEATURE_COMPAT_HAS_JOURNAL set.
 111      */
 112     uint8_t  s_journal_uuid[16];        /* uuid of journal superblock */
 113     uint32_t s_journal_inum;    /* inode number of journal file */
 114     uint32_t s_journal_dev;             /* device number of journal file */
 115     uint32_t s_last_orphan;             /* start of list of inodes to delete */
 116     uint32_t s_hash_seed[4];    /* HTREE hash seed */
 117     uint8_t  s_def_hash_version;        /* Default hash version to use */
 118     uint8_t  s_reserved_char_pad;
 119     uint16_t s_desc_size;               /* size of group descriptor */
 120     uint32_t s_default_mount_opts;
 121     uint32_t s_first_meta_bg;   /* First metablock block group */
 122     uint32_t s_mkfs_time;               /* When the filesystem was created */
 123     uint32_t s_jnl_blocks[17];  /* Backup of the journal inode */
 124     /* 64bit support valid if EXT4_FEATURE_COMPAT_64BIT */
 125     uint32_t s_blocks_count_hi; /* Blocks count */
 126     uint32_t s_r_blocks_count_hi;       /* Reserved blocks count */
 127     uint32_t s_free_blocks_count_hi;/* Free blocks count */
 128     uint16_t s_min_extra_isize; /* All inodes have at least # bytes */
 129     uint16_t s_want_extra_isize;        /* New inodes should reserve # bytes */
 130     uint32_t s_flags;           /* Miscellaneous flags */
 131     uint16_t s_raid_stride;             /* RAID stride */
 132     uint16_t s_mmp_interval;        /* # seconds to wait in MMP checking */
 133     uint64_t s_mmp_block;           /* Block for multi-mount protection */
 134     uint32_t s_raid_stripe_width;   /* blocks on all data disks (N*stride)*/
 135     uint8_t  s_log_groups_per_flex; /* FLEX_BG group size */
 136     uint8_t  s_reserved_char_pad2;
 137     uint16_t s_reserved_pad;
 138     uint32_t s_reserved[162];        /* Padding to the end of the block */
 139 };
 140
 141 /*******************************************************************************
 142 #ifndef DEPEND
 143 #if ext2_super_block_size != 1024
 144 #error ext2_super_block definition bogus
 145 #endif
 146 #endif
 147 *******************************************************************************/
 148
 149 /*
 150  *  ext2 group desc structure:
 151  */
 152 struct ext2_group_desc {
 153     uint32_t bg_block_bitmap;   /* Blocks bitmap block */
 154     uint32_t bg_inode_bitmap;   /* Inodes bitmap block */
 155     uint32_t bg_inode_table;    /* Inodes table block */
 156     uint16_t bg_free_blocks_count;      /* Free blocks count */
 157     uint16_t bg_free_inodes_count;      /* Free inodes count */
 158     uint16_t bg_used_dirs_count;        /* Directories count */
 159     uint16_t bg_pad;
 160     uint32_t bg_reserved[3];
 161 };
 162
 163 /*******************************************************************************
 164 #ifndef DEPEND
 165 #if ext2_group_desc_size != 32
 166 #error ext2_group_desc definition bogus
 167 #endif
 168 #endif
 169 *******************************************************************************/
 170
 171
 172 /*
 173  * ext2 inode structure:
 174  */
 175 struct ext2_inode {
 176     uint16_t i_mode;            /* File mode */
 177     uint16_t i_uid;             /* Owner Uid */
 178     uint32_t i_size;            /* 4: Size in bytes */
 179     uint32_t i_atime;           /* Access time */
 180     uint32_t i_ctime;           /* 12: Creation time */
 181     uint32_t i_mtime;           /* Modification time */
 182     uint32_t i_dtime;           /* 20: Deletion Time */
 183     uint16_t i_gid;             /* Group Id */
 184     uint16_t i_links_count;     /* 24: Links count */
 185     uint32_t i_blocks;          /* Blocks count */
 186     uint32_t i_flags;           /* 32: File flags */
 187     uint32_t l_i_reserved1;
 188     uint32_t i_block[EXT2_N_BLOCKS];    /* 40: Pointers to blocks */
 189     uint32_t i_version;         /* File version (for NFS) */
 190     uint32_t i_file_acl;        /* File ACL */
 191     uint32_t i_dir_acl;         /* Directory ACL */
 192     uint32_t i_faddr;           /* Fragment address */
 193     uint8_t  l_i_frag;          /* Fragment number */
 194     uint8_t  l_i_fsize;         /* Fragment size */
 195     uint16_t i_pad1;
 196     uint32_t l_i_reserved2[2];
 197 };
 198
 199 /*******************************************************************************
 200 #ifndef DEPEND
 201 #if ext2_inode_size != 128
 202 #error ext2_inode definition bogus
 203 #endif
 204 #endif
 205 *******************************************************************************/
 206
 207
 208 #define EXT2_NAME_LEN 255
 209 struct ext2_dir_entry {
 210     unsigned int        d_inode;                /* Inode number */
 211     unsigned short      d_rec_len;              /* Directory entry length */
 212     unsigned char       d_name_len;             /* Name length */
 213     unsigned char       d_file_type;
 214     char        d_name[EXT2_NAME_LEN];          /* File name */
 215 };
 216
 217 /*******************************************************************************
 218 #define EXT2_DIR_PAD     4
 219 #define EXT2_DIR_ROUND  (EXT2_DIR_PAD - 1)
 220 #define EXT2_DIR_REC_LEN(name_len)      (((name_len) + 8 + EXT2_DIR_ROUND) & \
 221                                          ~EXT2_DIR_ROUND)
 222 *******************************************************************************/
 223
 224
 225
 226
 227
 228
 229 /*
 230  * This is the extent on-disk structure.
 231  * It's used at the bottom of the tree.
 232  */
 233 struct ext4_extent {
 234     uint32_t ee_block;          /* first logical block extent covers */
 235     uint16_t ee_len;            /* number of blocks covered by extent */
 236     uint16_t ee_start_hi;       /* high 16 bits of physical block */
 237     uint32_t ee_start_lo;       /* low 32 bits of physical block */
 238 };
 239
 240 /*
 241  * This is index on-disk structure.
 242  * It's used at all the levels except the bottom.
 243  */
 244 struct ext4_extent_idx {
 245     uint32_t ei_block;          /* index covers logical blocks from 'block' */
 246     uint32_t ei_leaf_lo;        /* pointer to the physical block of the next *
 247                                  * level. leaf or next index could be there */
 248     uint16_t ei_leaf_hi;        /* high 16 bits of physical block */
 249     uint16_t ei_unused;
 250 };
 251
 252 /*
 253  * Each block (leaves and indexes), even inode-stored has header.
 254  */
 255 struct ext4_extent_header {
 256     uint16_t eh_magic;          /* probably will support different formats */
 257     uint16_t eh_entries;        /* number of valid entries */
 258     uint16_t eh_max;            /* capacity of store in entries */
 259     uint16_t eh_depth;          /* has tree real underlying blocks? */
 260     uint32_t eh_generation;     /* generation of the tree */
 261 };
 262
 263
 264
 265 #define EXT4_FIRST_EXTENT(header) ( (struct ext4_extent *)(header + 1) )
 266 #define EXT4_FIRST_INDEX(header)  ( (struct ext4_extent_idx *) (header + 1) )
 267
 268
 269 /*
 270  * The ext2 super block information in memory
 271  */
 272 struct ext2_sb_info {
 273     uint32_t s_inodes_per_block;/* Number of inodes per block */
 274     uint32_t s_inodes_per_group;/* Number of inodes in a group */
 275     uint32_t s_blocks_per_group;/* Number of blocks in a group */
 276     uint32_t s_desc_per_block;  /* Number of group descriptors per block */
 277     uint32_t s_groups_count;    /* Number of groups in the fs */
 278     uint32_t s_first_data_block;        /* First Data Block */
 279     int      s_inode_size;
 280 };
 281
 282 static inline struct ext2_sb_info *EXT2_SB(struct fs_info *fs)
 283 {
 284     return fs->fs_info;
 285 }
 286
 287 #define EXT2_BLOCKS_PER_GROUP(fs)      (EXT2_SB(fs)->s_blocks_per_group)
 288 #define EXT2_INODES_PER_GROUP(fs)      (EXT2_SB(fs)->s_inodes_per_group)
 289 #define EXT2_INODES_PER_BLOCK(fs)      (EXT2_SB(fs)->s_inodes_per_block)
 290 #define EXT2_DESC_PER_BLOCK(fs)        (EXT2_SB(fs)->s_desc_per_block)
 291
 292 /*
 293  * ext2 private inode information
 294  */
 295 struct ext2_pvt_inode {
 296     union {
 297         uint32_t i_block[EXT2_N_BLOCKS];
 298         struct ext4_extent_header i_extent_hdr;
 299     };
 300 };
 301
 302 #define PVT(i) ((struct ext2_pvt_inode *)((i)->pvt))
 303
 304 /*
 305  * functions
 306  */
 307 block_t ext2_bmap(struct inode *, block_t, size_t *);
 308 int ext2_next_extent(struct inode *, uint32_t);
 309
 310 #endif /* ext2_fs.h */