initialize.c revision 4564c727e9613da61688abbf6dbd879b19f20648
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#include "ext2_fs.h" 28#include "ext2fs.h" 29 30#if defined(__linux__) && defined(EXT2_OS_LINUX) 31#define CREATOR_OS EXT2_OS_LINUX 32#elif defined(__GNU__) && defined(EXT2_OS_HURD) 33#define CREATOR_OS EXT2_OS_HURD 34#elif defined(__FreeBSD__) && defined(EXT2_OS_FREEBSD) 35#define CREATOR_OS EXT2_OS_FREEBSD 36#elif defined(LITES) && defined(EXT2_OS_LITES) 37#define CREATOR_OS EXT2_OS_LITES 38#else 39#define CREATOR_OS EXT2_OS_LINUX /* by default */ 40#endif 41 42/* 43 * Note we override the kernel include file's idea of what the default 44 * check interval (never) should be. It's a good idea to check at 45 * least *occasionally*, specially since servers will never rarely get 46 * to reboot, since Linux is so robust these days. :-) 47 * 48 * 180 days (six months) seems like a good value. 49 */ 50#ifdef EXT2_DFL_CHECKINTERVAL 51#undef EXT2_DFL_CHECKINTERVAL 52#endif 53#define EXT2_DFL_CHECKINTERVAL (86400L * 180L) 54 55errcode_t ext2fs_initialize(const char *name, int flags, 56 struct ext2_super_block *param, 57 io_manager manager, ext2_filsys *ret_fs) 58{ 59 ext2_filsys fs; 60 errcode_t retval; 61 struct ext2_super_block *super; 62 int frags_per_block; 63 int rem; 64 int overhead = 0; 65 blk_t group_block; 66 int ipg; 67 int i, j; 68 blk_t numblocks; 69 char *buf; 70 int meta_bg_size, meta_bg, has_super, old_desc_blocks; 71 72 if (!param || !param->s_blocks_count) 73 return EXT2_ET_INVALID_ARGUMENT; 74 75 retval = ext2fs_get_mem(sizeof(struct struct_ext2_filsys), 76 (void **) &fs); 77 if (retval) 78 return retval; 79 80 memset(fs, 0, sizeof(struct struct_ext2_filsys)); 81 fs->magic = EXT2_ET_MAGIC_EXT2FS_FILSYS; 82 fs->flags = flags | EXT2_FLAG_RW; 83 fs->umask = 022; 84#ifdef WORDS_BIGENDIAN 85 fs->flags |= EXT2_FLAG_SWAP_BYTES; 86#endif 87 retval = manager->open(name, IO_FLAG_RW, &fs->io); 88 if (retval) 89 goto cleanup; 90 fs->io->app_data = fs; 91 retval = ext2fs_get_mem(strlen(name)+1, (void **) &fs->device_name); 92 if (retval) 93 goto cleanup; 94 95 strcpy(fs->device_name, name); 96 retval = ext2fs_get_mem(SUPERBLOCK_SIZE, (void **) &super); 97 if (retval) 98 goto cleanup; 99 fs->super = super; 100 101 memset(super, 0, SUPERBLOCK_SIZE); 102 103#define set_field(field, default) (super->field = param->field ? \ 104 param->field : (default)) 105 106 super->s_magic = EXT2_SUPER_MAGIC; 107 super->s_state = EXT2_VALID_FS; 108 109 set_field(s_log_block_size, 0); /* default blocksize: 1024 bytes */ 110 set_field(s_log_frag_size, 0); /* default fragsize: 1024 bytes */ 111 set_field(s_first_data_block, super->s_log_block_size ? 0 : 1); 112 set_field(s_max_mnt_count, EXT2_DFL_MAX_MNT_COUNT); 113 set_field(s_errors, EXT2_ERRORS_DEFAULT); 114 set_field(s_feature_compat, 0); 115 set_field(s_feature_incompat, 0); 116 set_field(s_feature_ro_compat, 0); 117 set_field(s_first_meta_bg, 0); 118 if (super->s_feature_incompat & ~EXT2_LIB_FEATURE_INCOMPAT_SUPP) 119 return EXT2_ET_UNSUPP_FEATURE; 120 if (super->s_feature_ro_compat & ~EXT2_LIB_FEATURE_RO_COMPAT_SUPP) 121 return EXT2_ET_RO_UNSUPP_FEATURE; 122 123 set_field(s_rev_level, EXT2_GOOD_OLD_REV); 124 if (super->s_rev_level >= EXT2_DYNAMIC_REV) { 125 set_field(s_first_ino, EXT2_GOOD_OLD_FIRST_INO); 126 set_field(s_inode_size, EXT2_GOOD_OLD_INODE_SIZE); 127 } 128 129 set_field(s_checkinterval, EXT2_DFL_CHECKINTERVAL); 130 super->s_mkfs_time = super->s_lastcheck = time(NULL); 131 132 super->s_creator_os = CREATOR_OS; 133 134 fs->blocksize = EXT2_BLOCK_SIZE(super); 135 fs->fragsize = EXT2_FRAG_SIZE(super); 136 frags_per_block = fs->blocksize / fs->fragsize; 137 138 /* default: (fs->blocksize*8) blocks/group, up to 2^16 (GDT limit) */ 139 set_field(s_blocks_per_group, fs->blocksize * 8); 140 if (super->s_blocks_per_group > EXT2_MAX_BLOCKS_PER_GROUP(super)) 141 super->s_blocks_per_group = EXT2_MAX_BLOCKS_PER_GROUP(super); 142 super->s_frags_per_group = super->s_blocks_per_group * frags_per_block; 143 144 super->s_blocks_count = param->s_blocks_count; 145 super->s_r_blocks_count = param->s_r_blocks_count; 146 if (super->s_r_blocks_count >= param->s_blocks_count) { 147 retval = EXT2_ET_INVALID_ARGUMENT; 148 goto cleanup; 149 } 150 151 /* 152 * If we're creating an external journal device, we don't need 153 * to bother with the rest. 154 */ 155 if (super->s_feature_incompat & 156 EXT3_FEATURE_INCOMPAT_JOURNAL_DEV) { 157 fs->group_desc_count = 0; 158 ext2fs_mark_super_dirty(fs); 159 *ret_fs = fs; 160 return 0; 161 } 162 163retry: 164 fs->group_desc_count = (super->s_blocks_count - 165 super->s_first_data_block + 166 EXT2_BLOCKS_PER_GROUP(super) - 1) 167 / EXT2_BLOCKS_PER_GROUP(super); 168 if (fs->group_desc_count == 0) 169 return EXT2_ET_TOOSMALL; 170 fs->desc_blocks = (fs->group_desc_count + 171 EXT2_DESC_PER_BLOCK(super) - 1) 172 / EXT2_DESC_PER_BLOCK(super); 173 174 i = fs->blocksize >= 4096 ? 1 : 4096 / fs->blocksize; 175 set_field(s_inodes_count, super->s_blocks_count / i); 176 177 /* 178 * Make sure we have at least EXT2_FIRST_INO + 1 inodes, so 179 * that we have enough inodes for the filesystem(!) 180 */ 181 if (super->s_inodes_count < EXT2_FIRST_INODE(super)+1) 182 super->s_inodes_count = EXT2_FIRST_INODE(super)+1; 183 184 /* 185 * There should be at least as many inodes as the user 186 * requested. Figure out how many inodes per group that 187 * should be. But make sure that we don't allocate more than 188 * one bitmap's worth of inodes each group. 189 */ 190 ipg = (super->s_inodes_count + fs->group_desc_count - 1) / 191 fs->group_desc_count; 192 if (ipg > fs->blocksize * 8) { 193 if (super->s_blocks_per_group >= 256) { 194 /* Try again with slightly different parameters */ 195 super->s_blocks_per_group -= 8; 196 super->s_blocks_count = param->s_blocks_count; 197 super->s_frags_per_group = super->s_blocks_per_group * 198 frags_per_block; 199 goto retry; 200 } else 201 return EXT2_ET_TOO_MANY_INODES; 202 } 203 204 if (ipg > EXT2_MAX_INODES_PER_GROUP(super)) 205 ipg = EXT2_MAX_INODES_PER_GROUP(super); 206 207 super->s_inodes_per_group = ipg; 208 if (super->s_inodes_count > ipg * fs->group_desc_count) 209 super->s_inodes_count = ipg * fs->group_desc_count; 210 211 /* 212 * Make sure the number of inodes per group completely fills 213 * the inode table blocks in the descriptor. If not, add some 214 * additional inodes/group. Waste not, want not... 215 */ 216 fs->inode_blocks_per_group = (((super->s_inodes_per_group * 217 EXT2_INODE_SIZE(super)) + 218 EXT2_BLOCK_SIZE(super) - 1) / 219 EXT2_BLOCK_SIZE(super)); 220 super->s_inodes_per_group = ((fs->inode_blocks_per_group * 221 EXT2_BLOCK_SIZE(super)) / 222 EXT2_INODE_SIZE(super)); 223 /* 224 * Finally, make sure the number of inodes per group is a 225 * multiple of 8. This is needed to simplify the bitmap 226 * splicing code. 227 */ 228 super->s_inodes_per_group &= ~7; 229 fs->inode_blocks_per_group = (((super->s_inodes_per_group * 230 EXT2_INODE_SIZE(super)) + 231 EXT2_BLOCK_SIZE(super) - 1) / 232 EXT2_BLOCK_SIZE(super)); 233 234 /* 235 * adjust inode count to reflect the adjusted inodes_per_group 236 */ 237 super->s_inodes_count = super->s_inodes_per_group * 238 fs->group_desc_count; 239 super->s_free_inodes_count = super->s_inodes_count; 240 241 /* 242 * Overhead is the number of bookkeeping blocks per group. It 243 * includes the superblock backup, the group descriptor 244 * backups, the inode bitmap, the block bitmap, and the inode 245 * table. 246 * 247 * XXX Not all block groups need the descriptor blocks, but 248 * being clever is tricky... 249 */ 250 overhead = (int) (3 + fs->desc_blocks + fs->inode_blocks_per_group); 251 252 /* This can only happen if the user requested too many inodes */ 253 if (overhead > super->s_blocks_per_group) 254 return EXT2_ET_TOO_MANY_INODES; 255 256 /* 257 * See if the last group is big enough to support the 258 * necessary data structures. If not, we need to get rid of 259 * it. 260 */ 261 rem = (int) ((super->s_blocks_count - super->s_first_data_block) % 262 super->s_blocks_per_group); 263 if ((fs->group_desc_count == 1) && rem && (rem < overhead)) 264 return EXT2_ET_TOOSMALL; 265 if (rem && (rem < overhead+50)) { 266 super->s_blocks_count -= rem; 267 goto retry; 268 } 269 270 /* 271 * At this point we know how big the filesystem will be. So 272 * we can do any and all allocations that depend on the block 273 * count. 274 */ 275 276 retval = ext2fs_get_mem(strlen(fs->device_name) + 80, 277 (void **) &buf); 278 if (retval) 279 goto cleanup; 280 281 sprintf(buf, "block bitmap for %s", fs->device_name); 282 retval = ext2fs_allocate_block_bitmap(fs, buf, &fs->block_map); 283 if (retval) 284 goto cleanup; 285 286 sprintf(buf, "inode bitmap for %s", fs->device_name); 287 retval = ext2fs_allocate_inode_bitmap(fs, buf, &fs->inode_map); 288 if (retval) 289 goto cleanup; 290 291 ext2fs_free_mem((void **) &buf); 292 293 retval = ext2fs_get_mem((size_t) fs->desc_blocks * fs->blocksize, 294 (void **) &fs->group_desc); 295 if (retval) 296 goto cleanup; 297 298 memset(fs->group_desc, 0, (size_t) fs->desc_blocks * fs->blocksize); 299 300 /* 301 * Reserve the superblock and group descriptors for each 302 * group, and fill in the correct group statistics for group. 303 * Note that although the block bitmap, inode bitmap, and 304 * inode table have not been allocated (and in fact won't be 305 * by this routine), they are accounted for nevertheless. 306 */ 307 group_block = super->s_first_data_block; 308 super->s_free_blocks_count = 0; 309 if (fs->super->s_feature_incompat & EXT2_FEATURE_INCOMPAT_META_BG) 310 old_desc_blocks = fs->super->s_first_meta_bg; 311 else 312 old_desc_blocks = fs->desc_blocks; 313 for (i = 0; i < fs->group_desc_count; i++) { 314 if (i == fs->group_desc_count-1) { 315 numblocks = (fs->super->s_blocks_count - 316 fs->super->s_first_data_block) % 317 fs->super->s_blocks_per_group; 318 if (!numblocks) 319 numblocks = fs->super->s_blocks_per_group; 320 } else 321 numblocks = fs->super->s_blocks_per_group; 322 323 has_super = ext2fs_bg_has_super(fs, i); 324 325 if (has_super) { 326 ext2fs_mark_block_bitmap(fs->block_map, group_block); 327 numblocks--; 328 } 329 meta_bg_size = (fs->blocksize / 330 sizeof (struct ext2_group_desc)); 331 meta_bg = i / meta_bg_size; 332 333 if (!(fs->super->s_feature_incompat & 334 EXT2_FEATURE_INCOMPAT_META_BG) || 335 (meta_bg < fs->super->s_first_meta_bg)) { 336 if (has_super) { 337 for (j=0; j < old_desc_blocks; j++) 338 ext2fs_mark_block_bitmap(fs->block_map, 339 group_block + j + 1); 340 numblocks -= old_desc_blocks; 341 } 342 } else { 343 if (has_super) 344 has_super = 1; 345 if (((i % meta_bg_size) == 0) || 346 ((i % meta_bg_size) == 1) || 347 ((i % meta_bg_size) == (meta_bg_size-1))) { 348 ext2fs_mark_block_bitmap(fs->block_map, 349 group_block + has_super); 350 numblocks--; 351 } 352 } 353 354 numblocks -= 2 + fs->inode_blocks_per_group; 355 356 super->s_free_blocks_count += numblocks; 357 fs->group_desc[i].bg_free_blocks_count = numblocks; 358 fs->group_desc[i].bg_free_inodes_count = 359 fs->super->s_inodes_per_group; 360 fs->group_desc[i].bg_used_dirs_count = 0; 361 362 group_block += super->s_blocks_per_group; 363 } 364 365 ext2fs_mark_super_dirty(fs); 366 ext2fs_mark_bb_dirty(fs); 367 ext2fs_mark_ib_dirty(fs); 368 369 io_channel_set_blksize(fs->io, fs->blocksize); 370 371 *ret_fs = fs; 372 return 0; 373cleanup: 374 ext2fs_free(fs); 375 return retval; 376} 377