initialize.c revision a112847b39386f9e7332ba5e5a0a5e54cfe301cc
1/* 2 * initialize.c --- initialize a filesystem handle given superblock 3 * parameters. Used by mke2fs when initializing a filesystem. 4 * 5 * Copyright (C) 1994, 1995, 1996 Theodore Ts'o. 6 * 7 * %Begin-Header% 8 * This file may be redistributed under the terms of the GNU Public 9 * License. 10 * %End-Header% 11 */ 12 13#include <stdio.h> 14#include <string.h> 15#if HAVE_UNISTD_H 16#include <unistd.h> 17#endif 18#include <fcntl.h> 19#include <time.h> 20#if HAVE_SYS_STAT_H 21#include <sys/stat.h> 22#endif 23#if HAVE_SYS_TYPES_H 24#include <sys/types.h> 25#endif 26 27#if EXT2_FLAT_INCLUDES 28#include "ext2_fs.h" 29#else 30#include <linux/ext2_fs.h> 31#endif 32 33#include "ext2fs.h" 34 35#if defined(__linux__) && defined(EXT2_OS_LINUX) 36#define CREATOR_OS EXT2_OS_LINUX 37#elif defined(__GNU__) && defined(EXT2_OS_HURD) 38#define CREATOR_OS EXT2_OS_HURD 39#elif defined(__FreeBSD__) && defined(EXT2_OS_FREEBSD) 40#define CREATOR_OS EXT2_OS_FREEBSD 41#elif defined(LITES) && defined(EXT2_OS_LITES) 42#define CREATOR_OS EXT2_OS_LITES 43#else 44#define CREATOR_OS EXT2_OS_LINUX /* by default */ 45#endif 46 47/* 48 * Note we override the kernel include file's idea of what the default 49 * check interval (never) should be. It's a good idea to check at 50 * least *occasionally*, specially since servers will never rarely get 51 * to reboot, since Linux is so robust these days. :-) 52 * 53 * 180 days (six months) seems like a good value. 54 */ 55#ifdef EXT2_DFL_CHECKINTERVAL 56#undef EXT2_DFL_CHECKINTERVAL 57#endif 58#define EXT2_DFL_CHECKINTERVAL (86400L * 180L) 59 60errcode_t ext2fs_initialize(const char *name, int flags, 61 struct ext2_super_block *param, 62 io_manager manager, ext2_filsys *ret_fs) 63{ 64 ext2_filsys fs; 65 errcode_t retval; 66 struct ext2_super_block *super; 67 int frags_per_block; 68 int rem; 69 int overhead = 0; 70 blk_t group_block; 71 int i, j; 72 blk_t numblocks; 73 char *buf; 74 75 if (!param || !param->s_blocks_count) 76 return EXT2_ET_INVALID_ARGUMENT; 77 78 retval = ext2fs_get_mem(sizeof(struct struct_ext2_filsys), 79 (void **) &fs); 80 if (retval) 81 return retval; 82 83 memset(fs, 0, sizeof(struct struct_ext2_filsys)); 84 fs->magic = EXT2_ET_MAGIC_EXT2FS_FILSYS; 85 fs->flags = flags | EXT2_FLAG_RW | ext2fs_native_flag(); 86 retval = manager->open(name, IO_FLAG_RW, &fs->io); 87 if (retval) 88 goto cleanup; 89 fs->io->app_data = fs; 90 retval = ext2fs_get_mem(strlen(name)+1, (void **) &fs->device_name); 91 if (retval) 92 goto cleanup; 93 94 strcpy(fs->device_name, name); 95 retval = ext2fs_get_mem(SUPERBLOCK_SIZE, (void **) &super); 96 if (retval) 97 goto cleanup; 98 fs->super = super; 99 100 memset(super, 0, SUPERBLOCK_SIZE); 101 102#define set_field(field, default) (super->field = param->field ? \ 103 param->field : (default)) 104 105 super->s_magic = EXT2_SUPER_MAGIC; 106 super->s_state = EXT2_VALID_FS; 107 108 set_field(s_log_block_size, 0); /* default blocksize: 1024 bytes */ 109 set_field(s_log_frag_size, 0); /* default fragsize: 1024 bytes */ 110 set_field(s_first_data_block, super->s_log_block_size ? 0 : 1); 111 set_field(s_max_mnt_count, EXT2_DFL_MAX_MNT_COUNT); 112 set_field(s_errors, EXT2_ERRORS_DEFAULT); 113 set_field(s_feature_compat, 0); 114 set_field(s_feature_incompat, 0); 115 set_field(s_feature_ro_compat, 0); 116 if (super->s_feature_incompat & ~EXT2_LIB_FEATURE_INCOMPAT_SUPP) 117 return EXT2_ET_UNSUPP_FEATURE; 118 if (super->s_feature_ro_compat & ~EXT2_LIB_FEATURE_RO_COMPAT_SUPP) 119 return EXT2_ET_RO_UNSUPP_FEATURE; 120 121 set_field(s_rev_level, EXT2_GOOD_OLD_REV); 122 if (super->s_rev_level >= EXT2_DYNAMIC_REV) { 123 set_field(s_first_ino, EXT2_GOOD_OLD_FIRST_INO); 124 set_field(s_inode_size, EXT2_GOOD_OLD_INODE_SIZE); 125 } 126 127 set_field(s_checkinterval, EXT2_DFL_CHECKINTERVAL); 128 super->s_lastcheck = time(NULL); 129 130 super->s_creator_os = CREATOR_OS; 131 132 fs->blocksize = EXT2_BLOCK_SIZE(super); 133 fs->fragsize = EXT2_FRAG_SIZE(super); 134 frags_per_block = fs->blocksize / fs->fragsize; 135 136 /* default: (fs->blocksize*8) blocks/group */ 137 set_field(s_blocks_per_group, fs->blocksize*8); 138 super->s_frags_per_group = super->s_blocks_per_group * frags_per_block; 139 140 super->s_blocks_count = param->s_blocks_count; 141 super->s_r_blocks_count = param->s_r_blocks_count; 142 if (super->s_r_blocks_count >= param->s_blocks_count) { 143 retval = EXT2_ET_INVALID_ARGUMENT; 144 goto cleanup; 145 } 146 147 /* 148 * If we're creating an external journal device, we don't need 149 * to bother with the rest. 150 */ 151 if (super->s_feature_incompat & 152 EXT3_FEATURE_INCOMPAT_JOURNAL_DEV) { 153 fs->group_desc_count = 0; 154 ext2fs_mark_super_dirty(fs); 155 *ret_fs = fs; 156 return 0; 157 } 158 159retry: 160 fs->group_desc_count = (super->s_blocks_count - 161 super->s_first_data_block + 162 EXT2_BLOCKS_PER_GROUP(super) - 1) 163 / EXT2_BLOCKS_PER_GROUP(super); 164 if (fs->group_desc_count == 0) 165 return EXT2_ET_TOOSMALL; 166 fs->desc_blocks = (fs->group_desc_count + 167 EXT2_DESC_PER_BLOCK(super) - 1) 168 / EXT2_DESC_PER_BLOCK(super); 169 170 /* n.b., fs->blocksize is <= 4096 */ 171 set_field(s_inodes_count, super->s_blocks_count/(4096/fs->blocksize)); 172 173 /* 174 * Make sure we have at least EXT2_FIRST_INO + 1 inodes, so 175 * that we have enough inodes for the filesystem(!) 176 */ 177 if (super->s_inodes_count < EXT2_FIRST_INODE(super)+1) 178 super->s_inodes_count = EXT2_FIRST_INODE(super)+1; 179 180 /* 181 * There should be at least as many inodes as the user 182 * requested. Figure out how many inodes per group that 183 * should be. But make sure that we don't allocate more than 184 * one bitmap's worth of inodes 185 */ 186 super->s_inodes_per_group = (super->s_inodes_count + 187 fs->group_desc_count - 1) / 188 fs->group_desc_count; 189 if (super->s_inodes_per_group > fs->blocksize*8) 190 super->s_inodes_per_group = fs->blocksize*8; 191 192 /* 193 * Make sure the number of inodes per group completely fills 194 * the inode table blocks in the descriptor. If not, add some 195 * additional inodes/group. Waste not, want not... 196 */ 197 fs->inode_blocks_per_group = (((super->s_inodes_per_group * 198 EXT2_INODE_SIZE(super)) + 199 EXT2_BLOCK_SIZE(super) - 1) / 200 EXT2_BLOCK_SIZE(super)); 201 super->s_inodes_per_group = ((fs->inode_blocks_per_group * 202 EXT2_BLOCK_SIZE(super)) / 203 EXT2_INODE_SIZE(super)); 204 /* 205 * Finally, make sure the number of inodes per group is a 206 * multiple of 8. This is needed to simplify the bitmap 207 * splicing code. 208 */ 209 super->s_inodes_per_group &= ~7; 210 fs->inode_blocks_per_group = (((super->s_inodes_per_group * 211 EXT2_INODE_SIZE(super)) + 212 EXT2_BLOCK_SIZE(super) - 1) / 213 EXT2_BLOCK_SIZE(super)); 214 215 /* 216 * adjust inode count to reflect the adjusted inodes_per_group 217 */ 218 super->s_inodes_count = super->s_inodes_per_group * 219 fs->group_desc_count; 220 super->s_free_inodes_count = super->s_inodes_count; 221 222 /* 223 * Overhead is the number of bookkeeping blocks per group. It 224 * includes the superblock backup, the group descriptor 225 * backups, the inode bitmap, the block bitmap, and the inode 226 * table. 227 * 228 * XXX Not all block groups need the descriptor blocks, but 229 * being clever is tricky... 230 */ 231 overhead = (int) (3 + fs->desc_blocks + fs->inode_blocks_per_group); 232 233 /* 234 * See if the last group is big enough to support the 235 * necessary data structures. If not, we need to get rid of 236 * it. 237 */ 238 rem = (int) ((super->s_blocks_count - super->s_first_data_block) % 239 super->s_blocks_per_group); 240 if ((fs->group_desc_count == 1) && rem && (rem < overhead)) 241 return EXT2_ET_TOOSMALL; 242 if (rem && (rem < overhead+50)) { 243 super->s_blocks_count -= rem; 244 goto retry; 245 } 246 247 /* 248 * At this point we know how big the filesystem will be. So 249 * we can do any and all allocations that depend on the block 250 * count. 251 */ 252 253 retval = ext2fs_get_mem(strlen(fs->device_name) + 80, 254 (void **) &buf); 255 if (retval) 256 goto cleanup; 257 258 sprintf(buf, "block bitmap for %s", fs->device_name); 259 retval = ext2fs_allocate_block_bitmap(fs, buf, &fs->block_map); 260 if (retval) 261 goto cleanup; 262 263 sprintf(buf, "inode bitmap for %s", fs->device_name); 264 retval = ext2fs_allocate_inode_bitmap(fs, buf, &fs->inode_map); 265 if (retval) 266 goto cleanup; 267 268 ext2fs_free_mem((void **) &buf); 269 270 retval = ext2fs_get_mem((size_t) fs->desc_blocks * fs->blocksize, 271 (void **) &fs->group_desc); 272 if (retval) 273 goto cleanup; 274 275 memset(fs->group_desc, 0, (size_t) fs->desc_blocks * fs->blocksize); 276 277 /* 278 * Reserve the superblock and group descriptors for each 279 * group, and fill in the correct group statistics for group. 280 * Note that although the block bitmap, inode bitmap, and 281 * inode table have not been allocated (and in fact won't be 282 * by this routine), they are accounted for nevertheless. 283 */ 284 group_block = super->s_first_data_block; 285 super->s_free_blocks_count = 0; 286 for (i = 0; i < fs->group_desc_count; i++) { 287 if (i == fs->group_desc_count-1) { 288 numblocks = (fs->super->s_blocks_count - 289 fs->super->s_first_data_block) % 290 fs->super->s_blocks_per_group; 291 if (!numblocks) 292 numblocks = fs->super->s_blocks_per_group; 293 } else 294 numblocks = fs->super->s_blocks_per_group; 295 296 if (ext2fs_bg_has_super(fs, i)) { 297 for (j=0; j < fs->desc_blocks+1; j++) 298 ext2fs_mark_block_bitmap(fs->block_map, 299 group_block + j); 300 numblocks -= 1 + fs->desc_blocks; 301 } 302 303 numblocks -= 2 + fs->inode_blocks_per_group; 304 305 super->s_free_blocks_count += numblocks; 306 fs->group_desc[i].bg_free_blocks_count = numblocks; 307 fs->group_desc[i].bg_free_inodes_count = 308 fs->super->s_inodes_per_group; 309 fs->group_desc[i].bg_used_dirs_count = 0; 310 311 group_block += super->s_blocks_per_group; 312 } 313 314 ext2fs_mark_super_dirty(fs); 315 ext2fs_mark_bb_dirty(fs); 316 ext2fs_mark_ib_dirty(fs); 317 318 io_channel_set_blksize(fs->io, fs->blocksize); 319 320 *ret_fs = fs; 321 return 0; 322cleanup: 323 ext2fs_free(fs); 324 return retval; 325} 326 327 328 329