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 */ 128