1 /* 2 * Copyright (c) International Business Machines Corp., 2000 3 * 4 * This program is free software; you can redistribute it and/or modify 5 * it under the terms of the GNU General Public License as published by 6 * the Free Software Foundation; either version 3 of the License, or 7 * (at your option) any later version. 8 * 9 * This program is distributed in the hope that it will be useful, 10 * but WITHOUT ANY WARRANTY; without even the implied warranty of 11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See 12 * the GNU General Public License for more details. 13 * 14 * You should have received a copy of the GNU General Public License 15 * along with this program. If not, see <http://www.gnu.org/licenses/>. 16 * 17 */ 18 #ifndef _H_JFS_SUPERBLOCK 19 #define _H_JFS_SUPERBLOCK 20 /* 21 * jfs_superblock.h 22 */ 23 24 /* 25 * make the magic number something a human could read 26 */ 27 #define JFS_MAGIC "JFS1" /* Magic word: Version 1 */ 28 29 #define JFS_VERSION 1 /* Version number: Version 1 */ 30 31 #define LV_NAME_SIZE 11 /* MUST BE 11 for OS/2 boot sector */ 32 33 /* 34 * aggregate superblock 35 * 36 * The name superblock is too close to super_block, so the name has been 37 * changed to jfs_superblock. The utilities are still using the old name. 38 */ 39 #ifdef _JFS_UTILITY 40 struct superblock 41 #else 42 struct jfs_superblock 43 #endif 44 { 45 char s_magic[4]; /* 4: magic number */ 46 u32 s_version; /* 4: version number */ 47 48 s64 s_size; /* 8: aggregate size in hardware/LVM blocks; 49 * VFS: number of blocks 50 */ 51 s32 s_bsize; /* 4: aggregate block size in bytes; 52 * VFS: fragment size 53 */ 54 s16 s_l2bsize; /* 2: log2 of s_bsize */ 55 s16 s_l2bfactor; /* 2: log2(s_bsize/hardware block size) */ 56 s32 s_pbsize; /* 4: hardware/LVM block size in bytes */ 57 s16 s_l2pbsize; /* 2: log2 of s_pbsize */ 58 s16 pad; /* 2: padding necessary for alignment */ 59 60 u32 s_agsize; /* 4: allocation group size in aggr. blocks */ 61 62 u32 s_flag; /* 4: aggregate attributes: 63 * see jfs_filsys.h 64 */ 65 u32 s_state; /* 4: mount/unmount/recovery state: 66 * see jfs_filsys.h 67 */ 68 s32 s_compress; /* 4: > 0 if data compression */ 69 70 pxd_t s_ait2; /* 8: first extent of secondary 71 * aggregate inode table 72 */ 73 74 pxd_t s_aim2; /* 8: first extent of secondary 75 * aggregate inode map 76 */ 77 u32 s_logdev; /* 4: device address of log */ 78 s32 s_logserial; /* 4: log serial number at aggregate mount */ 79 pxd_t s_logpxd; /* 8: inline log extent */ 80 81 pxd_t s_fsckpxd; /* 8: inline fsck work space extent */ 82 83 struct timestruc_t s_time; /* 8: time last updated */ 84 85 s32 s_fsckloglen; /* 4: Number of file system blocks reserved for 86 * the fsck service log. 87 * N.B. These blocks are divided among the 88 * versions kept. This is not a per 89 * version size. 90 * N.B. These blocks are included in the 91 * length field of s_fsckpxd. 92 */ 93 s8 s_fscklog; /* 1: which fsck service log is most recent 94 * 0 => no service log data yet 95 * 1 => the first one 96 * 2 => the 2nd one 97 */ 98 char s_fpack[11]; /* 11: file system volume name 99 * N.B. This must be 11 bytes to 100 * conform with the OS/2 BootSector 101 * requirements 102 */ 103 104 /* extendfs() parameter under s_state & FM_EXTENDFS */ 105 s64 s_xsize; /* 8: extendfs s_size */ 106 pxd_t s_xfsckpxd; /* 8: extendfs fsckpxd */ 107 pxd_t s_xlogpxd; /* 8: extendfs logpxd */ 108 /* - 128 byte boundary - */ 109 110 /* 111 * DFS VFS support (preliminary) 112 */ 113 char s_attach; /* 1: VFS: flag: set when aggregate is attached 114 */ 115 u8 rsrvd4[7]; /* 7: reserved - set to 0 */ 116 117 u64 totalUsable; /* 8: VFS: total of 1K blocks which are 118 * available to "normal" (non-root) users. 119 */ 120 u64 minFree; /* 8: VFS: # of 1K blocks held in reserve for 121 * exclusive use of root. This value can be 0, 122 * and if it is then totalUsable will be equal 123 * to # of blocks in aggregate. I believe this 124 * means that minFree + totalUsable = # blocks. 125 * In that case, we don't need to store both 126 * totalUsable and minFree since we can compute 127 * one from the other. I would guess minFree 128 * would be the one we should store, and 129 * totalUsable would be the one we should 130 * compute. (Just a guess...) 131 */ 132 133 u64 realFree; /* 8: VFS: # of free 1K blocks can be used by 134 * "normal" users. It may be this is something 135 * we should compute when asked for instead of 136 * storing in the superblock. I don't know how 137 * often this information is needed. 138 */ 139 /* 140 * graffiti area 141 */ 142 }; 143 144 #endif /*_H_JFS_SUPERBLOCK */ 145