| /* |
| * The second extended file system magic number |
| */ |
| #define EXT2_SUPER_MAGIC 0xEF53 |
| |
| /* |
| * Structure of the super block |
| */ |
| struct ext2_super_block { |
| __le32 s_inodes_count; /* Inodes count */ |
| __le32 s_blocks_count; /* Blocks count */ |
| __le32 s_r_blocks_count; /* Reserved blocks count */ |
| __le32 s_free_blocks_count; /* Free blocks count */ |
| __le32 s_free_inodes_count; /* Free inodes count */ |
| __le32 s_first_data_block; /* First Data Block */ |
| __le32 s_log_block_size; /* Block size */ |
| __le32 s_log_frag_size; /* Fragment size */ |
| __le32 s_blocks_per_group; /* # Blocks per group */ |
| __le32 s_frags_per_group; /* # Fragments per group */ |
| __le32 s_inodes_per_group; /* # Inodes per group */ |
| __le32 s_mtime; /* Mount time */ |
| __le32 s_wtime; /* Write time */ |
| __le16 s_mnt_count; /* Mount count */ |
| __le16 s_max_mnt_count; /* Maximal mount count */ |
| __le16 s_magic; /* Magic signature */ |
| __le16 s_state; /* File system state */ |
| __le16 s_errors; /* Behaviour when detecting errors */ |
| __le16 s_minor_rev_level; /* minor revision level */ |
| __le32 s_lastcheck; /* time of last check */ |
| __le32 s_checkinterval; /* max. time between checks */ |
| __le32 s_creator_os; /* OS */ |
| __le32 s_rev_level; /* Revision level */ |
| __le16 s_def_resuid; /* Default uid for reserved blocks */ |
| __le16 s_def_resgid; /* Default gid for reserved blocks */ |
| /* |
| * These fields are for EXT2_DYNAMIC_REV superblocks only. |
| * |
| * Note: the difference between the compatible feature set and |
| * the incompatible feature set is that if there is a bit set |
| * in the incompatible feature set that the kernel doesn't |
| * know about, it should refuse to mount the filesystem. |
| * |
| * e2fsck's requirements are more strict; if it doesn't know |
| * about a feature in either the compatible or incompatible |
| * feature set, it must abort and not try to meddle with |
| * things it doesn't understand... |
| */ |
| __le32 s_first_ino; /* First non-reserved inode */ |
| __le16 s_inode_size; /* size of inode structure */ |
| __le16 s_block_group_nr; /* block group # of this superblock */ |
| __le32 s_feature_compat; /* compatible feature set */ |
| __le32 s_feature_incompat; /* incompatible feature set */ |
| __le32 s_feature_ro_compat; /* readonly-compatible feature set */ |
| __u8 s_uuid[16]; /* 128-bit uuid for volume */ |
| char s_volume_name[16]; /* volume name */ |
| char s_last_mounted[64]; /* directory where last mounted */ |
| __le32 s_algorithm_usage_bitmap; /* For compression */ |
| /* |
| * Performance hints. Directory preallocation should only |
| * happen if the EXT2_COMPAT_PREALLOC flag is on. |
| */ |
| __u8 s_prealloc_blocks; /* Nr of blocks to try to preallocate*/ |
| __u8 s_prealloc_dir_blocks; /* Nr to preallocate for dirs */ |
| __u16 s_padding1; |
| /* |
| * Journaling support valid if EXT3_FEATURE_COMPAT_HAS_JOURNAL set. |
| */ |
| __u8 s_journal_uuid[16]; /* uuid of journal superblock */ |
| __u32 s_journal_inum; /* inode number of journal file */ |
| __u32 s_journal_dev; /* device number of journal file */ |
| __u32 s_last_orphan; /* start of list of inodes to delete */ |
| __u32 s_hash_seed[4]; /* HTREE hash seed */ |
| __u8 s_def_hash_version; /* Default hash version to use */ |
| __u8 s_reserved_char_pad; |
| __u16 s_reserved_word_pad; |
| __le32 s_default_mount_opts; |
| __le32 s_first_meta_bg; /* First metablock block group */ |
| __u32 s_reserved[190]; /* Padding to the end of the block */ |
| }; |
