fstype/ext4_fs.h

   1 /*
   2  * ext4 support added by Omegamoon
   3  *
   4  * -Ext4 file systems will have EXT4_FEATURE_INCOMPAT_EXTENTS, while Ext3 will not.
   5  */
   6
   7 #define EXT4_SUPER_MAGIC                    0xEF53
   8 #define EXT4_FEATURE_COMPAT_HAS_JOURNAL     0x0004
   9 #define EXT4_FEATURE_INCOMPAT_EXTENTS       0x0040
  10
  11 /*
  12  * Structure of the super block
  13  */
  14 struct ext4_super_block {
  15 /*00*/  __le32  s_inodes_count;         /* Inodes count */
  16         __le32  s_blocks_count_lo;      /* Blocks count */
  17         __le32  s_r_blocks_count_lo;    /* Reserved blocks count */
  18         __le32  s_free_blocks_count_lo; /* Free blocks count */
  19 /*10*/  __le32  s_free_inodes_count;    /* Free inodes count */
  20         __le32  s_first_data_block;     /* First Data Block */
  21         __le32  s_log_block_size;       /* Block size */
  22         __le32  s_obso_log_frag_size;   /* Obsoleted fragment size */
  23 /*20*/  __le32  s_blocks_per_group;     /* # Blocks per group */
  24         __le32  s_obso_frags_per_group; /* Obsoleted fragments per group */
  25         __le32  s_inodes_per_group;     /* # Inodes per group */
  26         __le32  s_mtime;                /* Mount time */
  27 /*30*/  __le32  s_wtime;                /* Write time */
  28         __le16  s_mnt_count;            /* Mount count */
  29         __le16  s_max_mnt_count;        /* Maximal mount count */
  30         __le16  s_magic;                /* Magic signature */
  31         __le16  s_state;                /* File system state */
  32         __le16  s_errors;               /* Behaviour when detecting errors */
  33         __le16  s_minor_rev_level;      /* minor revision level */
  34 /*40*/  __le32  s_lastcheck;            /* time of last check */
  35         __le32  s_checkinterval;        /* max. time between checks */
  36         __le32  s_creator_os;           /* OS */
  37         __le32  s_rev_level;            /* Revision level */
  38 /*50*/  __le16  s_def_resuid;           /* Default uid for reserved blocks */
  39         __le16  s_def_resgid;           /* Default gid for reserved blocks */
  40         /*
  41          * These fields are for EXT4_DYNAMIC_REV superblocks only.
  42          *
  43          * Note: the difference between the compatible feature set and
  44          * the incompatible feature set is that if there is a bit set
  45          * in the incompatible feature set that the kernel doesn't
  46          * know about, it should refuse to mount the filesystem.
  47          *
  48          * e2fsck's requirements are more strict; if it doesn't know
  49          * about a feature in either the compatible or incompatible
  50          * feature set, it must abort and not try to meddle with
  51          * things it doesn't understand...
  52          */
  53         __le32  s_first_ino;            /* First non-reserved inode */
  54         __le16  s_inode_size;           /* size of inode structure */
  55         __le16  s_block_group_nr;       /* block group # of this superblock */
  56         __le32  s_feature_compat;       /* compatible feature set */
  57 /*60*/  __le32  s_feature_incompat;     /* incompatible feature set */
  58         __le32  s_feature_ro_compat;    /* readonly-compatible feature set */
  59 /*68*/  __u8    s_uuid[16];             /* 128-bit uuid for volume */
  60 /*78*/  char    s_volume_name[16];      /* volume name */
  61 /*88*/  char    s_last_mounted[64];     /* directory where last mounted */
  62 /*C8*/  __le32  s_algorithm_usage_bitmap; /* For compression */
  63         /*
  64          * Performance hints.  Directory preallocation should only
  65          * happen if the EXT4_FEATURE_COMPAT_DIR_PREALLOC flag is on.
  66          */
  67         __u8    s_prealloc_blocks;      /* Nr of blocks to try to preallocate*/
  68         __u8    s_prealloc_dir_blocks;  /* Nr to preallocate for dirs */
  69         __le16  s_reserved_gdt_blocks;  /* Per group desc for online growth */
  70         /*
  71          * Journaling support valid if EXT4_FEATURE_COMPAT_HAS_JOURNAL set.
  72          */
  73 /*D0*/  __u8    s_journal_uuid[16];     /* uuid of journal superblock */
  74 /*E0*/  __le32  s_journal_inum;         /* inode number of journal file */
  75         __le32  s_journal_dev;          /* device number of journal file */
  76         __le32  s_last_orphan;          /* start of list of inodes to delete */
  77         __le32  s_hash_seed[4];         /* HTREE hash seed */
  78         __u8    s_def_hash_version;     /* Default hash version to use */
  79         __u8    s_reserved_char_pad;
  80         __le16  s_desc_size;            /* size of group descriptor */
  81 /*100*/ __le32  s_default_mount_opts;
  82         __le32  s_first_meta_bg;        /* First metablock block group */
  83         __le32  s_mkfs_time;            /* When the filesystem was created */
  84         __le32  s_jnl_blocks[17];       /* Backup of the journal inode */
  85         /* 64bit support valid if EXT4_FEATURE_COMPAT_64BIT */
  86 /*150*/ __le32  s_blocks_count_hi;      /* Blocks count */
  87         __le32  s_r_blocks_count_hi;    /* Reserved blocks count */
  88         __le32  s_free_blocks_count_hi; /* Free blocks count */
  89         __le16  s_min_extra_isize;      /* All inodes have at least # bytes */
  90         __le16  s_want_extra_isize;     /* New inodes should reserve # bytes */
  91         __le32  s_flags;                /* Miscellaneous flags */
  92         __le16  s_raid_stride;          /* RAID stride */
  93         __le16  s_mmp_interval;         /* # seconds to wait in MMP checking */
  94         __le64  s_mmp_block;            /* Block for multi-mount protection */
  95         __le32  s_raid_stripe_width;    /* blocks on all data disks (N*stride)*/
  96         __u8    s_log_groups_per_flex;  /* FLEX_BG group size */
  97         __u8    s_reserved_char_pad2;
  98         __le16  s_reserved_pad;
  99         __u32   s_reserved[162];        /* Padding to the end of the block */
 100 };