initialize.c revision baf8ab980e73e6600ac1ec45e6058796fc9dc0b0
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#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 (sb->s_blocks_count < max_blocks / 1024) 79 max_blocks = sb->s_blocks_count * 1024; 80 rsv_groups = ext2fs_div_ceil(max_blocks - sb->s_first_data_block, bpg); 81 rsv_gdb = ext2fs_div_ceil(rsv_groups, gdpb) - fs->desc_blocks; 82 if (rsv_gdb > EXT2_ADDR_PER_BLOCK(sb)) 83 rsv_gdb = EXT2_ADDR_PER_BLOCK(sb); 84#ifdef RES_GDT_DEBUG 85 printf("max_blocks %lu, rsv_groups = %lu, rsv_gdb = %u\n", 86 max_blocks, rsv_groups, rsv_gdb); 87#endif 88 89 return rsv_gdb; 90} 91 92errcode_t ext2fs_initialize(const char *name, int flags, 93 struct ext2_super_block *param, 94 io_manager manager, ext2_filsys *ret_fs) 95{ 96 ext2_filsys fs; 97 errcode_t retval; 98 struct ext2_super_block *super; 99 int frags_per_block; 100 unsigned int rem; 101 unsigned int overhead = 0; 102 unsigned int ipg; 103 dgrp_t i; 104 blk_t numblocks; 105 int rsv_gdt; 106 int csum_flag; 107 int io_flags; 108 char *buf = 0; 109 char c; 110 111 if (!param || !param->s_blocks_count) 112 return EXT2_ET_INVALID_ARGUMENT; 113 114 retval = ext2fs_get_mem(sizeof(struct struct_ext2_filsys), &fs); 115 if (retval) 116 return retval; 117 118 memset(fs, 0, sizeof(struct struct_ext2_filsys)); 119 fs->magic = EXT2_ET_MAGIC_EXT2FS_FILSYS; 120 fs->flags = flags | EXT2_FLAG_RW; 121 fs->umask = 022; 122#ifdef WORDS_BIGENDIAN 123 fs->flags |= EXT2_FLAG_SWAP_BYTES; 124#endif 125 io_flags = IO_FLAG_RW; 126 if (flags & EXT2_FLAG_EXCLUSIVE) 127 io_flags |= IO_FLAG_EXCLUSIVE; 128 retval = manager->open(name, io_flags, &fs->io); 129 if (retval) 130 goto cleanup; 131 fs->image_io = fs->io; 132 fs->io->app_data = fs; 133 retval = ext2fs_get_mem(strlen(name)+1, &fs->device_name); 134 if (retval) 135 goto cleanup; 136 137 strcpy(fs->device_name, name); 138 retval = ext2fs_get_mem(SUPERBLOCK_SIZE, &super); 139 if (retval) 140 goto cleanup; 141 fs->super = super; 142 143 memset(super, 0, SUPERBLOCK_SIZE); 144 145#define set_field(field, default) (super->field = param->field ? \ 146 param->field : (default)) 147 148 super->s_magic = EXT2_SUPER_MAGIC; 149 super->s_state = EXT2_VALID_FS; 150 151 set_field(s_log_block_size, 0); /* default blocksize: 1024 bytes */ 152 set_field(s_log_frag_size, 0); /* default fragsize: 1024 bytes */ 153 set_field(s_first_data_block, super->s_log_block_size ? 0 : 1); 154 set_field(s_max_mnt_count, EXT2_DFL_MAX_MNT_COUNT); 155 set_field(s_errors, EXT2_ERRORS_DEFAULT); 156 set_field(s_feature_compat, 0); 157 set_field(s_feature_incompat, 0); 158 set_field(s_feature_ro_compat, 0); 159 set_field(s_first_meta_bg, 0); 160 set_field(s_raid_stride, 0); /* default stride size: 0 */ 161 set_field(s_raid_stripe_width, 0); /* default stripe width: 0 */ 162 set_field(s_log_groups_per_flex, 0); 163 set_field(s_flags, 0); 164 if (super->s_feature_incompat & ~EXT2_LIB_FEATURE_INCOMPAT_SUPP) { 165 retval = EXT2_ET_UNSUPP_FEATURE; 166 goto cleanup; 167 } 168 if (super->s_feature_ro_compat & ~EXT2_LIB_FEATURE_RO_COMPAT_SUPP) { 169 retval = EXT2_ET_RO_UNSUPP_FEATURE; 170 goto cleanup; 171 } 172 173 set_field(s_rev_level, EXT2_GOOD_OLD_REV); 174 if (super->s_rev_level >= EXT2_DYNAMIC_REV) { 175 set_field(s_first_ino, EXT2_GOOD_OLD_FIRST_INO); 176 set_field(s_inode_size, EXT2_GOOD_OLD_INODE_SIZE); 177 if (super->s_inode_size >= sizeof(struct ext2_inode_large)) { 178 int extra_isize = sizeof(struct ext2_inode_large) - 179 EXT2_GOOD_OLD_INODE_SIZE; 180 set_field(s_min_extra_isize, extra_isize); 181 set_field(s_want_extra_isize, extra_isize); 182 } 183 } else { 184 super->s_first_ino = EXT2_GOOD_OLD_FIRST_INO; 185 super->s_inode_size = EXT2_GOOD_OLD_INODE_SIZE; 186 } 187 188 set_field(s_checkinterval, EXT2_DFL_CHECKINTERVAL); 189 super->s_mkfs_time = super->s_lastcheck = fs->now ? fs->now : time(NULL); 190 191 super->s_creator_os = CREATOR_OS; 192 193 fs->blocksize = EXT2_BLOCK_SIZE(super); 194 fs->fragsize = EXT2_FRAG_SIZE(super); 195 frags_per_block = fs->blocksize / fs->fragsize; 196 197 /* default: (fs->blocksize*8) blocks/group, up to 2^16 (GDT limit) */ 198 set_field(s_blocks_per_group, fs->blocksize * 8); 199 if (super->s_blocks_per_group > EXT2_MAX_BLOCKS_PER_GROUP(super)) 200 super->s_blocks_per_group = EXT2_MAX_BLOCKS_PER_GROUP(super); 201 super->s_frags_per_group = super->s_blocks_per_group * frags_per_block; 202 203 super->s_blocks_count = param->s_blocks_count; 204 super->s_r_blocks_count = param->s_r_blocks_count; 205 if (super->s_r_blocks_count >= param->s_blocks_count) { 206 retval = EXT2_ET_INVALID_ARGUMENT; 207 goto cleanup; 208 } 209 210 /* 211 * If we're creating an external journal device, we don't need 212 * to bother with the rest. 213 */ 214 if (super->s_feature_incompat & EXT3_FEATURE_INCOMPAT_JOURNAL_DEV) { 215 fs->group_desc_count = 0; 216 ext2fs_mark_super_dirty(fs); 217 *ret_fs = fs; 218 return 0; 219 } 220 221retry: 222 fs->group_desc_count = ext2fs_div_ceil(super->s_blocks_count - 223 super->s_first_data_block, 224 EXT2_BLOCKS_PER_GROUP(super)); 225 if (fs->group_desc_count == 0) { 226 retval = EXT2_ET_TOOSMALL; 227 goto cleanup; 228 } 229 fs->desc_blocks = ext2fs_div_ceil(fs->group_desc_count, 230 EXT2_DESC_PER_BLOCK(super)); 231 232 i = fs->blocksize >= 4096 ? 1 : 4096 / fs->blocksize; 233 set_field(s_inodes_count, super->s_blocks_count / i); 234 235 /* 236 * Make sure we have at least EXT2_FIRST_INO + 1 inodes, so 237 * that we have enough inodes for the filesystem(!) 238 */ 239 if (super->s_inodes_count < EXT2_FIRST_INODE(super)+1) 240 super->s_inodes_count = EXT2_FIRST_INODE(super)+1; 241 242 /* 243 * There should be at least as many inodes as the user 244 * requested. Figure out how many inodes per group that 245 * should be. But make sure that we don't allocate more than 246 * one bitmap's worth of inodes each group. 247 */ 248 ipg = ext2fs_div_ceil(super->s_inodes_count, fs->group_desc_count); 249 if (ipg > fs->blocksize * 8) { 250 if (super->s_blocks_per_group >= 256) { 251 /* Try again with slightly different parameters */ 252 super->s_blocks_per_group -= 8; 253 super->s_blocks_count = param->s_blocks_count; 254 super->s_frags_per_group = super->s_blocks_per_group * 255 frags_per_block; 256 goto retry; 257 } else { 258 retval = EXT2_ET_TOO_MANY_INODES; 259 goto cleanup; 260 } 261 } 262 263 if (ipg > (unsigned) EXT2_MAX_INODES_PER_GROUP(super)) 264 ipg = EXT2_MAX_INODES_PER_GROUP(super); 265 266ipg_retry: 267 super->s_inodes_per_group = ipg; 268 269 /* 270 * Make sure the number of inodes per group completely fills 271 * the inode table blocks in the descriptor. If not, add some 272 * additional inodes/group. Waste not, want not... 273 */ 274 fs->inode_blocks_per_group = (((super->s_inodes_per_group * 275 EXT2_INODE_SIZE(super)) + 276 EXT2_BLOCK_SIZE(super) - 1) / 277 EXT2_BLOCK_SIZE(super)); 278 super->s_inodes_per_group = ((fs->inode_blocks_per_group * 279 EXT2_BLOCK_SIZE(super)) / 280 EXT2_INODE_SIZE(super)); 281 /* 282 * Finally, make sure the number of inodes per group is a 283 * multiple of 8. This is needed to simplify the bitmap 284 * splicing code. 285 */ 286 super->s_inodes_per_group &= ~7; 287 fs->inode_blocks_per_group = (((super->s_inodes_per_group * 288 EXT2_INODE_SIZE(super)) + 289 EXT2_BLOCK_SIZE(super) - 1) / 290 EXT2_BLOCK_SIZE(super)); 291 292 /* 293 * adjust inode count to reflect the adjusted inodes_per_group 294 */ 295 if ((__u64)super->s_inodes_per_group * fs->group_desc_count > ~0U) { 296 ipg--; 297 goto ipg_retry; 298 } 299 super->s_inodes_count = super->s_inodes_per_group * 300 fs->group_desc_count; 301 super->s_free_inodes_count = super->s_inodes_count; 302 303 /* 304 * check the number of reserved group descriptor table blocks 305 */ 306 if (super->s_feature_compat & EXT2_FEATURE_COMPAT_RESIZE_INODE) 307 rsv_gdt = calc_reserved_gdt_blocks(fs); 308 else 309 rsv_gdt = 0; 310 set_field(s_reserved_gdt_blocks, rsv_gdt); 311 if (super->s_reserved_gdt_blocks > EXT2_ADDR_PER_BLOCK(super)) { 312 retval = EXT2_ET_RES_GDT_BLOCKS; 313 goto cleanup; 314 } 315 316 /* 317 * Calculate the maximum number of bookkeeping blocks per 318 * group. It includes the superblock, the block group 319 * descriptors, the block bitmap, the inode bitmap, the inode 320 * table, and the reserved gdt blocks. 321 */ 322 overhead = (int) (3 + fs->inode_blocks_per_group + 323 fs->desc_blocks + super->s_reserved_gdt_blocks); 324 325 /* This can only happen if the user requested too many inodes */ 326 if (overhead > super->s_blocks_per_group) { 327 retval = EXT2_ET_TOO_MANY_INODES; 328 goto cleanup; 329 } 330 331 /* 332 * See if the last group is big enough to support the 333 * necessary data structures. If not, we need to get rid of 334 * it. We need to recalculate the overhead for the last block 335 * group, since it might or might not have a superblock 336 * backup. 337 */ 338 overhead = (int) (2 + fs->inode_blocks_per_group); 339 if (ext2fs_bg_has_super(fs, fs->group_desc_count - 1)) 340 overhead += 1 + fs->desc_blocks + super->s_reserved_gdt_blocks; 341 rem = ((super->s_blocks_count - super->s_first_data_block) % 342 super->s_blocks_per_group); 343 if ((fs->group_desc_count == 1) && rem && (rem < overhead)) { 344 retval = EXT2_ET_TOOSMALL; 345 goto cleanup; 346 } 347 if (rem && (rem < overhead+50)) { 348 super->s_blocks_count -= rem; 349 goto retry; 350 } 351 352 /* 353 * At this point we know how big the filesystem will be. So 354 * we can do any and all allocations that depend on the block 355 * count. 356 */ 357 358 retval = ext2fs_get_mem(strlen(fs->device_name) + 80, &buf); 359 if (retval) 360 goto cleanup; 361 362 strcpy(buf, "block bitmap for "); 363 strcat(buf, fs->device_name); 364 retval = ext2fs_allocate_block_bitmap(fs, buf, &fs->block_map); 365 if (retval) 366 goto cleanup; 367 368 strcpy(buf, "inode bitmap for "); 369 strcat(buf, fs->device_name); 370 retval = ext2fs_allocate_inode_bitmap(fs, buf, &fs->inode_map); 371 if (retval) 372 goto cleanup; 373 374 ext2fs_free_mem(&buf); 375 376 retval = ext2fs_get_array(fs->desc_blocks, fs->blocksize, 377 &fs->group_desc); 378 if (retval) 379 goto cleanup; 380 381 memset(fs->group_desc, 0, (size_t) fs->desc_blocks * fs->blocksize); 382 383 /* 384 * Reserve the superblock and group descriptors for each 385 * group, and fill in the correct group statistics for group. 386 * Note that although the block bitmap, inode bitmap, and 387 * inode table have not been allocated (and in fact won't be 388 * by this routine), they are accounted for nevertheless. 389 * 390 * If FLEX_BG meta-data grouping is used, only account for the 391 * superblock and group descriptors (the inode tables and 392 * bitmaps will be accounted for when allocated). 393 */ 394 super->s_free_blocks_count = 0; 395 csum_flag = EXT2_HAS_RO_COMPAT_FEATURE(fs->super, 396 EXT4_FEATURE_RO_COMPAT_GDT_CSUM); 397 for (i = 0; i < fs->group_desc_count; i++) { 398 /* 399 * Don't set the BLOCK_UNINIT group for the last group 400 * because the block bitmap needs to be padded. 401 */ 402 if (csum_flag) { 403 if (i != fs->group_desc_count - 1) 404 fs->group_desc[i].bg_flags |= 405 EXT2_BG_BLOCK_UNINIT; 406 fs->group_desc[i].bg_flags |= EXT2_BG_INODE_UNINIT; 407 numblocks = super->s_inodes_per_group; 408 if (i == 0) 409 numblocks -= super->s_first_ino; 410 fs->group_desc[i].bg_itable_unused = numblocks; 411 } 412 numblocks = ext2fs_reserve_super_and_bgd(fs, i, fs->block_map); 413 if (fs->super->s_log_groups_per_flex) 414 numblocks += 2 + fs->inode_blocks_per_group; 415 416 super->s_free_blocks_count += numblocks; 417 fs->group_desc[i].bg_free_blocks_count = numblocks; 418 fs->group_desc[i].bg_free_inodes_count = 419 fs->super->s_inodes_per_group; 420 fs->group_desc[i].bg_used_dirs_count = 0; 421 ext2fs_group_desc_csum_set(fs, i); 422 } 423 424 c = (char) 255; 425 if (((int) c) == -1) { 426 super->s_flags |= EXT2_FLAGS_SIGNED_HASH; 427 } else { 428 super->s_flags |= EXT2_FLAGS_UNSIGNED_HASH; 429 } 430 431 ext2fs_mark_super_dirty(fs); 432 ext2fs_mark_bb_dirty(fs); 433 ext2fs_mark_ib_dirty(fs); 434 435 io_channel_set_blksize(fs->io, fs->blocksize); 436 437 *ret_fs = fs; 438 return 0; 439cleanup: 440 if (buf) 441 free(buf); 442 ext2fs_free(fs); 443 return retval; 444} 445