minix/fs/ext2/super.h

   1 /* Super block table. The root file system and every mounted file system
   2  * has an entry here. The entry holds information about the sizes of the bit
   3  * maps and inodes.
   4  *
   5  * A super_block slot is free if s_dev == NO_DEV.
   6  *
   7  */
   8
   9 #ifndef EXT2_SUPER_H
  10 #define EXT2_SUPER_H
  11
  12 /* super_block (on-disk part) was taken from linux/include/linux/ext2_fs.h */
  13 EXTERN struct super_block {
  14     u32_t  s_inodes_count;         /* Inodes count */
  15     u32_t  s_blocks_count;         /* Blocks count */
  16     u32_t  s_r_blocks_count;       /* Reserved blocks count */
  17     u32_t  s_free_blocks_count;    /* Free blocks count */
  18     u32_t  s_free_inodes_count;    /* Free inodes count */
  19     u32_t  s_first_data_block;     /* First Data Block */
  20     u32_t  s_log_block_size;       /* Block size */
  21     u32_t  s_log_frag_size;        /* Fragment size */
  22     u32_t  s_blocks_per_group;     /* # Blocks per group */
  23     u32_t  s_frags_per_group;      /* # Fragments per group */
  24     u32_t  s_inodes_per_group;     /* # Inodes per group */
  25     u32_t  s_mtime;                /* Mount time */
  26     u32_t  s_wtime;                /* Write time */
  27     u16_t  s_mnt_count;            /* Mount count */
  28     u16_t  s_max_mnt_count;        /* Maximal mount count */
  29     u16_t  s_magic;                /* Magic signature */
  30     u16_t  s_state;                /* File system state */
  31     u16_t  s_errors;               /* Behaviour when detecting errors */
  32     u16_t  s_minor_rev_level;      /* minor revision level */
  33     u32_t  s_lastcheck;            /* time of last check */
  34     u32_t  s_checkinterval;        /* max. time between checks */
  35     u32_t  s_creator_os;           /* OS */
  36     u32_t  s_rev_level;            /* Revision level */
  37     u16_t  s_def_resuid;           /* Default uid for reserved blocks */
  38     u16_t  s_def_resgid;           /* Default gid for reserved blocks */
  39     /*
  40      * These fields are for EXT2_DYNAMIC_REV superblocks only.
  41      *
  42      * Note: the difference between the compatible feature set and
  43      * the incompatible feature set is that if there is a bit set
  44      * in the incompatible feature set that the kernel doesn't
  45      * know about, it should refuse to mount the filesystem.
  46      *
  47      * e2fsck's requirements are more strict; if it doesn't know
  48      * about a feature in either the compatible or incompatible
  49      * feature set, it must abort and not try to meddle with
  50      * things it doesn't understand...
  51      */
  52     u32_t  s_first_ino;            /* First non-reserved inode */
  53     u16_t  s_inode_size;           /* size of inode structure */
  54     u16_t  s_block_group_nr;       /* block group # of this superblock */
  55     u32_t  s_feature_compat;       /* compatible feature set */
  56     u32_t  s_feature_incompat;     /* incompatible feature set */
  57     u32_t  s_feature_ro_compat;    /* readonly-compatible feature set */
  58     u8_t   s_uuid[16];             /* 128-bit uuid for volume */
  59     char   s_volume_name[16];      /* volume name */
  60     char   s_last_mounted[64];     /* directory where last mounted */
  61     u32_t  s_algorithm_usage_bitmap; /* For compression */
  62     /*
  63      * Performance hints.  Directory preallocation should only
  64      * happen if the EXT2_COMPAT_PREALLOC flag is on.
  65      */
  66     u8_t    s_prealloc_blocks;      /* Nr of blocks to try to preallocate*/
  67     u8_t    s_prealloc_dir_blocks;  /* Nr to preallocate for dirs */
  68     u16_t   s_padding1;
  69     /*
  70      * Journaling support valid if EXT3_FEATURE_COMPAT_HAS_JOURNAL set.
  71      */
  72     u8_t    s_journal_uuid[16];     /* uuid of journal superblock */
  73     u32_t   s_journal_inum;         /* inode number of journal file */
  74     u32_t   s_journal_dev;          /* device number of journal file */
  75     u32_t   s_last_orphan;          /* start of list of inodes to delete */
  76     u32_t   s_hash_seed[4];         /* HTREE hash seed */
  77     u8_t    s_def_hash_version;     /* Default hash version to use */
  78     u8_t    s_reserved_char_pad;
  79     u16_t   s_reserved_word_pad;
  80     u32_t   s_default_mount_opts;
  81     u32_t   s_first_meta_bg;        /* First metablock block group */
  82     u32_t   s_reserved[190];        /* Padding to the end of the block */
  83
  84     /* The following items are only used when the super_block is in memory. */
  85     u32_t   s_inodes_per_block;     /* Number of inodes per block */
  86     u32_t   s_itb_per_group;        /* Number of inode table blocks per group */
  87     u32_t   s_gdb_count;            /* Number of group descriptor blocks */
  88     u32_t   s_desc_per_block;       /* Number of group descriptors per block */
  89     u32_t   s_groups_count;         /* Number of groups in the fs */
  90     u8_t    s_blocksize_bits;       /* Used to calculate offsets
  91                                      * (e.g. inode block),
  92                                      * always s_log_block_size+10.
  93                                      */
  94     struct group_desc *s_group_desc; /* Group descriptors read into RAM */
  95
  96     u16_t   s_block_size;       /* block size in bytes. */
  97     u16_t   s_sectors_in_block; /* s_block_size / 512 */
  98     u32_t   s_max_size;         /* maximum file size on this device */
  99     dev_t   s_dev;              /* whose super block is this? */
 100     int     s_rd_only;          /* set to 1 if file sys mounted read only */
 101     block_t s_bsearch;  /* all data blocks  below this block are in use*/
 102     int     s_igsearch; /* all groups below this one have no free inodes */
 103     u32_t   s_dirs_counter;
 104
 105 } *superblock, *ondisk_superblock;
 106
 107
 108 /* Structure of a blocks group descriptor.
 109  * On disk stored in little endian format.
 110  */
 111 struct group_desc
 112 {
 113     u32_t  block_bitmap;        /* Blocks bitmap block */
 114     u32_t  inode_bitmap;        /* Inodes bitmap block */
 115     u32_t  inode_table;         /* Inodes table block */
 116     u16_t  free_blocks_count;   /* Free blocks count */
 117     u16_t  free_inodes_count;   /* Free inodes count */
 118     u16_t  used_dirs_count;     /* Directories count */
 119     u16_t  pad;
 120     u32_t  reserved[3];
 121 };
 122
 123 #define IMAP    0           /* operating on the inode bit map */
 124 #define BMAP    1           /* operating on the block bit map */
 125 #define IMAPD   2           /* operating on the inode bit map, inode is dir */
 126
 127 #endif /* EXT2_SUPER_H */