#ifndef _MKFS_MFS_SUPER_H__ #define _MKFS_MFS_SUPER_H__ /* Super block table. The entry holds information about the sizes of the bit * maps and inodes. The s_ninodes field gives the number of inodes available * for files and directories, including the root directory. Inode 0 is * on the disk, but not used. Thus s_ninodes = 4 means that 5 bits will be * used in the bit map, bit 0, which is always 1 and not used, and bits 1-4 * for files and directories. The disk layout is: * * Item # blocks * boot block 1 * super block 1 * inode map s_imap_blocks * zone map s_zmap_blocks * inodes (s_ninodes + 'inodes per block' - 1)/'inodes per block' * unused whatever is needed to fill out the current zone * data zones (s_zones - s_firstdatazone) << s_log_zone_size */ struct super_block { uint16_t s_ninodes; /* # usable inodes on the minor device */ uint16_t s_nzones; /* total device size, including bit maps etc */ int16_t s_imap_blocks; /* # of blocks used by inode bit map */ int16_t s_zmap_blocks; /* # of blocks used by zone bit map */ uint16_t s_firstdatazone; /* number of first data zone (small) */ int16_t s_log_zone_size; /* log2 of blocks/zone */ uint32_t s_max_size; /* maximum file size on this device */ int16_t s_magic; /* magic number to recognize super-blocks */ } superblock; /* Some members have been overidden in later versions: */ #define s_firstdatazone_old s_firstdatazone #define s_zones s_nzones #undef MFSFLAG_CLEAN #undef MFSFLAG_MANDATORY_MASK #endif