initialize.c revision da3fc25bce5880c5d036d97727299ab09b415219
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 Library 9 * General Public License, version 2. 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#else 33#if defined(__GNU__) && defined(EXT2_OS_HURD) 34#define CREATOR_OS EXT2_OS_HURD 35#else 36#if defined(__FreeBSD__) && defined(EXT2_OS_FREEBSD) 37#define CREATOR_OS EXT2_OS_FREEBSD 38#else 39#if defined(LITES) && defined(EXT2_OS_LITES) 40#define CREATOR_OS EXT2_OS_LITES 41#else 42#define CREATOR_OS EXT2_OS_LINUX /* by default */ 43#endif /* defined(LITES) && defined(EXT2_OS_LITES) */ 44#endif /* defined(__FreeBSD__) && defined(EXT2_OS_FREEBSD) */ 45#endif /* defined(__GNU__) && defined(EXT2_OS_HURD) */ 46#endif /* defined(__linux__) && defined(EXT2_OS_LINUX) */ 47 48/* 49 * Note we override the kernel include file's idea of what the default 50 * check interval (never) should be. It's a good idea to check at 51 * least *occasionally*, specially since servers will never rarely get 52 * to reboot, since Linux is so robust these days. :-) 53 * 54 * 180 days (six months) seems like a good value. 55 */ 56#ifdef EXT2_DFL_CHECKINTERVAL 57#undef EXT2_DFL_CHECKINTERVAL 58#endif 59#define EXT2_DFL_CHECKINTERVAL (86400L * 180L) 60 61/* 62 * Calculate the number of GDT blocks to reserve for online filesystem growth. 63 * The absolute maximum number of GDT blocks we can reserve is determined by 64 * the number of block pointers that can fit into a single block. 65 */ 66static unsigned int calc_reserved_gdt_blocks(ext2_filsys fs) 67{ 68 struct ext2_super_block *sb = fs->super; 69 unsigned long bpg = sb->s_blocks_per_group; 70 unsigned int gdpb = EXT2_DESC_PER_BLOCK(sb); 71 unsigned long max_blocks = 0xffffffff; 72 unsigned long rsv_groups; 73 unsigned int rsv_gdb; 74 75 /* We set it at 1024x the current filesystem size, or 76 * the upper block count limit (2^32), whichever is lower. 77 */ 78 if (ext2fs_blocks_count(sb) < max_blocks / 1024) 79 max_blocks = ext2fs_blocks_count(sb) * 1024; 80 /* 81 * ext2fs_div64_ceil() is unnecessary because max_blocks is 82 * max _GDT_ blocks, which is limited to 32 bits. 83 */ 84 rsv_groups = ext2fs_div_ceil(max_blocks - sb->s_first_data_block, bpg); 85 rsv_gdb = ext2fs_div_ceil(rsv_groups, gdpb) - fs->desc_blocks; 86 if (rsv_gdb > EXT2_ADDR_PER_BLOCK(sb)) 87 rsv_gdb = EXT2_ADDR_PER_BLOCK(sb); 88#ifdef RES_GDT_DEBUG 89 printf("max_blocks %lu, rsv_groups = %lu, rsv_gdb = %u\n", 90 max_blocks, rsv_groups, rsv_gdb); 91#endif 92 93 return rsv_gdb; 94} 95 96errcode_t ext2fs_initialize(const char *name, int flags, 97 struct ext2_super_block *param, 98 io_manager manager, ext2_filsys *ret_fs) 99{ 100 ext2_filsys fs; 101 errcode_t retval; 102 struct ext2_super_block *super; 103 int frags_per_block; 104 unsigned int rem; 105 unsigned int overhead = 0; 106 unsigned int ipg; 107 dgrp_t i; 108 blk_t numblocks; 109 int rsv_gdt; 110 int csum_flag; 111 int io_flags; 112 char *buf = 0; 113 char c; 114 115 if (!param || !ext2fs_blocks_count(param)) 116 return EXT2_ET_INVALID_ARGUMENT; 117 118 retval = ext2fs_get_mem(sizeof(struct struct_ext2_filsys), &fs); 119 if (retval) 120 return retval; 121 122 memset(fs, 0, sizeof(struct struct_ext2_filsys)); 123 fs->magic = EXT2_ET_MAGIC_EXT2FS_FILSYS; 124 fs->flags = flags | EXT2_FLAG_RW; 125 fs->umask = 022; 126#ifdef WORDS_BIGENDIAN 127 fs->flags |= EXT2_FLAG_SWAP_BYTES; 128#endif 129 io_flags = IO_FLAG_RW; 130 if (flags & EXT2_FLAG_EXCLUSIVE) 131 io_flags |= IO_FLAG_EXCLUSIVE; 132 retval = manager->open(name, io_flags, &fs->io); 133 if (retval) 134 goto cleanup; 135 fs->image_io = fs->io; 136 fs->io->app_data = fs; 137 retval = ext2fs_get_mem(strlen(name)+1, &fs->device_name); 138 if (retval) 139 goto cleanup; 140 141 strcpy(fs->device_name, name); 142 retval = ext2fs_get_mem(SUPERBLOCK_SIZE, &super); 143 if (retval) 144 goto cleanup; 145 fs->super = super; 146 147 memset(super, 0, SUPERBLOCK_SIZE); 148 149#define set_field(field, default) (super->field = param->field ? \ 150 param->field : (default)) 151 152 super->s_magic = EXT2_SUPER_MAGIC; 153 super->s_state = EXT2_VALID_FS; 154 155 set_field(s_log_block_size, 0); /* default blocksize: 1024 bytes */ 156 set_field(s_log_frag_size, 0); /* default fragsize: 1024 bytes */ 157 set_field(s_first_data_block, super->s_log_block_size ? 0 : 1); 158 set_field(s_max_mnt_count, EXT2_DFL_MAX_MNT_COUNT); 159 set_field(s_errors, EXT2_ERRORS_DEFAULT); 160 set_field(s_feature_compat, 0); 161 set_field(s_feature_incompat, 0); 162 set_field(s_feature_ro_compat, 0); 163 set_field(s_first_meta_bg, 0); 164 set_field(s_raid_stride, 0); /* default stride size: 0 */ 165 set_field(s_raid_stripe_width, 0); /* default stripe width: 0 */ 166 set_field(s_log_groups_per_flex, 0); 167 set_field(s_flags, 0); 168 if (super->s_feature_incompat & ~EXT2_LIB_FEATURE_INCOMPAT_SUPP) { 169 retval = EXT2_ET_UNSUPP_FEATURE; 170 goto cleanup; 171 } 172 if (super->s_feature_ro_compat & ~EXT2_LIB_FEATURE_RO_COMPAT_SUPP) { 173 retval = EXT2_ET_RO_UNSUPP_FEATURE; 174 goto cleanup; 175 } 176 177 set_field(s_rev_level, EXT2_GOOD_OLD_REV); 178 if (super->s_rev_level >= EXT2_DYNAMIC_REV) { 179 set_field(s_first_ino, EXT2_GOOD_OLD_FIRST_INO); 180 set_field(s_inode_size, EXT2_GOOD_OLD_INODE_SIZE); 181 if (super->s_inode_size >= sizeof(struct ext2_inode_large)) { 182 int extra_isize = sizeof(struct ext2_inode_large) - 183 EXT2_GOOD_OLD_INODE_SIZE; 184 set_field(s_min_extra_isize, extra_isize); 185 set_field(s_want_extra_isize, extra_isize); 186 } 187 } else { 188 super->s_first_ino = EXT2_GOOD_OLD_FIRST_INO; 189 super->s_inode_size = EXT2_GOOD_OLD_INODE_SIZE; 190 } 191 192 set_field(s_checkinterval, EXT2_DFL_CHECKINTERVAL); 193 super->s_mkfs_time = super->s_lastcheck = fs->now ? fs->now : time(NULL); 194 195 super->s_creator_os = CREATOR_OS; 196 197 fs->blocksize = EXT2_BLOCK_SIZE(super); 198 fs->fragsize = EXT2_FRAG_SIZE(super); 199 frags_per_block = fs->blocksize / fs->fragsize; 200 201 /* default: (fs->blocksize*8) blocks/group, up to 2^16 (GDT limit) */ 202 set_field(s_blocks_per_group, fs->blocksize * 8); 203 if (super->s_blocks_per_group > EXT2_MAX_BLOCKS_PER_GROUP(super)) 204 super->s_blocks_per_group = EXT2_MAX_BLOCKS_PER_GROUP(super); 205 super->s_frags_per_group = super->s_blocks_per_group * frags_per_block; 206 207 ext2fs_blocks_count_set(super, ext2fs_blocks_count(param)); 208 ext2fs_r_blocks_count_set(super, ext2fs_r_blocks_count(param)); 209 if (ext2fs_r_blocks_count(super) >= ext2fs_blocks_count(param)) { 210 retval = EXT2_ET_INVALID_ARGUMENT; 211 goto cleanup; 212 } 213 214 /* 215 * If we're creating an external journal device, we don't need 216 * to bother with the rest. 217 */ 218 if (super->s_feature_incompat & EXT3_FEATURE_INCOMPAT_JOURNAL_DEV) { 219 fs->group_desc_count = 0; 220 ext2fs_mark_super_dirty(fs); 221 *ret_fs = fs; 222 return 0; 223 } 224 225retry: 226 fs->group_desc_count = (blk_t) ext2fs_div64_ceil( 227 ext2fs_blocks_count(super) - super->s_first_data_block, 228 EXT2_BLOCKS_PER_GROUP(super)); 229 if (fs->group_desc_count == 0) { 230 retval = EXT2_ET_TOOSMALL; 231 goto cleanup; 232 } 233 234 if (super->s_feature_incompat & EXT4_FEATURE_INCOMPAT_64BIT) 235 super->s_desc_size = EXT2_MIN_DESC_SIZE_64BIT; 236 237 fs->desc_blocks = ext2fs_div_ceil(fs->group_desc_count, 238 EXT2_DESC_PER_BLOCK(super)); 239 240 i = fs->blocksize >= 4096 ? 1 : 4096 / fs->blocksize; 241 242 if (super->s_feature_incompat & EXT4_FEATURE_INCOMPAT_64BIT && 243 (ext2fs_blocks_count(super) / i) > (1ULL << 32)) 244 set_field(s_inodes_count, ~0U); 245 else 246 set_field(s_inodes_count, ext2fs_blocks_count(super) / i); 247 248 /* 249 * Make sure we have at least EXT2_FIRST_INO + 1 inodes, so 250 * that we have enough inodes for the filesystem(!) 251 */ 252 if (super->s_inodes_count < EXT2_FIRST_INODE(super)+1) 253 super->s_inodes_count = EXT2_FIRST_INODE(super)+1; 254 255 /* 256 * There should be at least as many inodes as the user 257 * requested. Figure out how many inodes per group that 258 * should be. But make sure that we don't allocate more than 259 * one bitmap's worth of inodes each group. 260 */ 261 ipg = ext2fs_div_ceil(super->s_inodes_count, fs->group_desc_count); 262 if (ipg > fs->blocksize * 8) { 263 if (super->s_blocks_per_group >= 256) { 264 /* Try again with slightly different parameters */ 265 super->s_blocks_per_group -= 8; 266 ext2fs_blocks_count_set(super, 267 ext2fs_blocks_count(param)); 268 super->s_frags_per_group = super->s_blocks_per_group * 269 frags_per_block; 270 goto retry; 271 } else { 272 retval = EXT2_ET_TOO_MANY_INODES; 273 goto cleanup; 274 } 275 } 276 277 if (ipg > (unsigned) EXT2_MAX_INODES_PER_GROUP(super)) 278 ipg = EXT2_MAX_INODES_PER_GROUP(super); 279 280ipg_retry: 281 super->s_inodes_per_group = ipg; 282 283 /* 284 * Make sure the number of inodes per group completely fills 285 * the inode table blocks in the descriptor. If not, add some 286 * additional inodes/group. Waste not, want not... 287 */ 288 fs->inode_blocks_per_group = (((super->s_inodes_per_group * 289 EXT2_INODE_SIZE(super)) + 290 EXT2_BLOCK_SIZE(super) - 1) / 291 EXT2_BLOCK_SIZE(super)); 292 super->s_inodes_per_group = ((fs->inode_blocks_per_group * 293 EXT2_BLOCK_SIZE(super)) / 294 EXT2_INODE_SIZE(super)); 295 /* 296 * Finally, make sure the number of inodes per group is a 297 * multiple of 8. This is needed to simplify the bitmap 298 * splicing code. 299 */ 300 super->s_inodes_per_group &= ~7; 301 fs->inode_blocks_per_group = (((super->s_inodes_per_group * 302 EXT2_INODE_SIZE(super)) + 303 EXT2_BLOCK_SIZE(super) - 1) / 304 EXT2_BLOCK_SIZE(super)); 305 306 /* 307 * adjust inode count to reflect the adjusted inodes_per_group 308 */ 309 if ((__u64)super->s_inodes_per_group * fs->group_desc_count > ~0U) { 310 ipg--; 311 goto ipg_retry; 312 } 313 super->s_inodes_count = super->s_inodes_per_group * 314 fs->group_desc_count; 315 super->s_free_inodes_count = super->s_inodes_count; 316 317 /* 318 * check the number of reserved group descriptor table blocks 319 */ 320 if (super->s_feature_compat & EXT2_FEATURE_COMPAT_RESIZE_INODE) 321 rsv_gdt = calc_reserved_gdt_blocks(fs); 322 else 323 rsv_gdt = 0; 324 set_field(s_reserved_gdt_blocks, rsv_gdt); 325 if (super->s_reserved_gdt_blocks > EXT2_ADDR_PER_BLOCK(super)) { 326 retval = EXT2_ET_RES_GDT_BLOCKS; 327 goto cleanup; 328 } 329 330 /* 331 * Calculate the maximum number of bookkeeping blocks per 332 * group. It includes the superblock, the block group 333 * descriptors, the block bitmap, the inode bitmap, the inode 334 * table, and the reserved gdt blocks. 335 */ 336 overhead = (int) (3 + fs->inode_blocks_per_group + 337 fs->desc_blocks + super->s_reserved_gdt_blocks); 338 339 /* This can only happen if the user requested too many inodes */ 340 if (overhead > super->s_blocks_per_group) { 341 retval = EXT2_ET_TOO_MANY_INODES; 342 goto cleanup; 343 } 344 345 /* 346 * See if the last group is big enough to support the 347 * necessary data structures. If not, we need to get rid of 348 * it. We need to recalculate the overhead for the last block 349 * group, since it might or might not have a superblock 350 * backup. 351 */ 352 overhead = (int) (2 + fs->inode_blocks_per_group); 353 if (ext2fs_bg_has_super(fs, fs->group_desc_count - 1)) 354 overhead += 1 + fs->desc_blocks + super->s_reserved_gdt_blocks; 355 rem = ((ext2fs_blocks_count(super) - super->s_first_data_block) % 356 super->s_blocks_per_group); 357 if ((fs->group_desc_count == 1) && rem && (rem < overhead)) { 358 retval = EXT2_ET_TOOSMALL; 359 goto cleanup; 360 } 361 if (rem && (rem < overhead+50)) { 362 ext2fs_blocks_count_set(super, ext2fs_blocks_count(super) - 363 rem); 364 365 goto retry; 366 } 367 368 /* 369 * At this point we know how big the filesystem will be. So 370 * we can do any and all allocations that depend on the block 371 * count. 372 */ 373 374 retval = ext2fs_get_mem(strlen(fs->device_name) + 80, &buf); 375 if (retval) 376 goto cleanup; 377 378 strcpy(buf, "block bitmap for "); 379 strcat(buf, fs->device_name); 380 retval = ext2fs_allocate_block_bitmap(fs, buf, &fs->block_map); 381 if (retval) 382 goto cleanup; 383 384 strcpy(buf, "inode bitmap for "); 385 strcat(buf, fs->device_name); 386 retval = ext2fs_allocate_inode_bitmap(fs, buf, &fs->inode_map); 387 if (retval) 388 goto cleanup; 389 390 ext2fs_free_mem(&buf); 391 392 retval = ext2fs_get_array(fs->desc_blocks, fs->blocksize, 393 &fs->group_desc); 394 if (retval) 395 goto cleanup; 396 397 memset(fs->group_desc, 0, (size_t) fs->desc_blocks * fs->blocksize); 398 399 /* 400 * Reserve the superblock and group descriptors for each 401 * group, and fill in the correct group statistics for group. 402 * Note that although the block bitmap, inode bitmap, and 403 * inode table have not been allocated (and in fact won't be 404 * by this routine), they are accounted for nevertheless. 405 * 406 * If FLEX_BG meta-data grouping is used, only account for the 407 * superblock and group descriptors (the inode tables and 408 * bitmaps will be accounted for when allocated). 409 */ 410 ext2fs_free_blocks_count_set(super, 0); 411 csum_flag = EXT2_HAS_RO_COMPAT_FEATURE(fs->super, 412 EXT4_FEATURE_RO_COMPAT_GDT_CSUM); 413 for (i = 0; i < fs->group_desc_count; i++) { 414 /* 415 * Don't set the BLOCK_UNINIT group for the last group 416 * because the block bitmap needs to be padded. 417 */ 418 if (csum_flag) { 419 if (i != fs->group_desc_count - 1) 420 ext2fs_bg_flags_set(fs, i, 421 EXT2_BG_BLOCK_UNINIT); 422 ext2fs_bg_flags_set(fs, i, EXT2_BG_INODE_UNINIT); 423 numblocks = super->s_inodes_per_group; 424 if (i == 0) 425 numblocks -= super->s_first_ino; 426 ext2fs_bg_itable_unused_set(fs, i, numblocks); 427 } 428 numblocks = ext2fs_reserve_super_and_bgd(fs, i, fs->block_map); 429 if (fs->super->s_log_groups_per_flex) 430 numblocks += 2 + fs->inode_blocks_per_group; 431 432 ext2fs_free_blocks_count_set(super, 433 ext2fs_free_blocks_count(super) + 434 numblocks); 435 ext2fs_bg_free_blocks_count_set(fs, i, numblocks); 436 ext2fs_bg_free_inodes_count_set(fs, i, fs->super->s_inodes_per_group); 437 ext2fs_bg_used_dirs_count_set(fs, i, 0); 438 ext2fs_group_desc_csum_set(fs, i); 439 } 440 441 c = (char) 255; 442 if (((int) c) == -1) { 443 super->s_flags |= EXT2_FLAGS_SIGNED_HASH; 444 } else { 445 super->s_flags |= EXT2_FLAGS_UNSIGNED_HASH; 446 } 447 448 ext2fs_mark_super_dirty(fs); 449 ext2fs_mark_bb_dirty(fs); 450 ext2fs_mark_ib_dirty(fs); 451 452 io_channel_set_blksize(fs->io, fs->blocksize); 453 454 *ret_fs = fs; 455 return 0; 456cleanup: 457 free(buf); 458 ext2fs_free(fs); 459 return retval; 460} 461