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 */ 66 static 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 = fs->blocksize / sizeof(struct ext2_group_desc); 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 92 errcode_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 io_flags; 107 char *buf; 108 char c; 109 110 if (!param || !param->s_blocks_count) 111 return EXT2_ET_INVALID_ARGUMENT; 112 113 retval = ext2fs_get_mem(sizeof(struct struct_ext2_filsys), &fs); 114 if (retval) 115 return retval; 116 117 memset(fs, 0, sizeof(struct struct_ext2_filsys)); 118 fs->magic = EXT2_ET_MAGIC_EXT2FS_FILSYS; 119 fs->flags = flags | EXT2_FLAG_RW; 120 fs->umask = 022; 121 #ifdef WORDS_BIGENDIAN 122 fs->flags |= EXT2_FLAG_SWAP_BYTES; 123 #endif 124 io_flags = IO_FLAG_RW; 125 if (flags & EXT2_FLAG_EXCLUSIVE) 126 io_flags |= IO_FLAG_EXCLUSIVE; 127 retval = manager->open(name, io_flags, &fs->io); 128 if (retval) 129 goto cleanup; 130 fs->image_io = fs->io; 131 fs->io->app_data = fs; 132 retval = ext2fs_get_mem(strlen(name)+1, &fs->device_name); 133 if (retval) 134 goto cleanup; 135 136 strcpy(fs->device_name, name); 137 retval = ext2fs_get_mem(SUPERBLOCK_SIZE, &super); 138 if (retval) 139 goto cleanup; 140 fs->super = super; 141 142 memset(super, 0, SUPERBLOCK_SIZE); 143 144 #define set_field(field, default) (super->field = param->field ? \ 145 param->field : (default)) 146 147 super->s_magic = EXT2_SUPER_MAGIC; 148 super->s_state = EXT2_VALID_FS; 149 150 set_field(s_log_block_size, 0); /* default blocksize: 1024 bytes */ 151 set_field(s_log_frag_size, 0); /* default fragsize: 1024 bytes */ 152 set_field(s_first_data_block, super->s_log_block_size ? 0 : 1); 153 set_field(s_max_mnt_count, EXT2_DFL_MAX_MNT_COUNT); 154 set_field(s_errors, EXT2_ERRORS_DEFAULT); 155 set_field(s_feature_compat, 0); 156 set_field(s_feature_incompat, 0); 157 set_field(s_feature_ro_compat, 0); 158 set_field(s_first_meta_bg, 0); 159 set_field(s_raid_stride, 0); /* default stride size: 0 */ 160 set_field(s_raid_stripe_width, 0); /* default stripe width: 0 */ 161 set_field(s_flags, 0); 162 if (super->s_feature_incompat & ~EXT2_LIB_FEATURE_INCOMPAT_SUPP) { 163 retval = EXT2_ET_UNSUPP_FEATURE; 164 goto cleanup; 165 } 166 if (super->s_feature_ro_compat & ~EXT2_LIB_FEATURE_RO_COMPAT_SUPP) { 167 retval = EXT2_ET_RO_UNSUPP_FEATURE; 168 goto cleanup; 169 } 170 171 set_field(s_rev_level, EXT2_GOOD_OLD_REV); 172 if (super->s_rev_level >= EXT2_DYNAMIC_REV) { 173 set_field(s_first_ino, EXT2_GOOD_OLD_FIRST_INO); 174 set_field(s_inode_size, EXT2_GOOD_OLD_INODE_SIZE); 175 } 176 177 set_field(s_checkinterval, EXT2_DFL_CHECKINTERVAL); 178 super->s_mkfs_time = super->s_lastcheck = fs->now ? fs->now : time(NULL); 179 180 super->s_creator_os = CREATOR_OS; 181 182 fs->blocksize = EXT2_BLOCK_SIZE(super); 183 fs->fragsize = EXT2_FRAG_SIZE(super); 184 frags_per_block = fs->blocksize / fs->fragsize; 185 186 /* default: (fs->blocksize*8) blocks/group, up to 2^16 (GDT limit) */ 187 set_field(s_blocks_per_group, fs->blocksize * 8); 188 if (super->s_blocks_per_group > EXT2_MAX_BLOCKS_PER_GROUP(super)) 189 super->s_blocks_per_group = EXT2_MAX_BLOCKS_PER_GROUP(super); 190 super->s_frags_per_group = super->s_blocks_per_group * frags_per_block; 191 192 super->s_blocks_count = param->s_blocks_count; 193 super->s_r_blocks_count = param->s_r_blocks_count; 194 if (super->s_r_blocks_count >= param->s_blocks_count) { 195 retval = EXT2_ET_INVALID_ARGUMENT; 196 goto cleanup; 197 } 198 199 /* 200 * If we're creating an external journal device, we don't need 201 * to bother with the rest. 202 */ 203 if (super->s_feature_incompat & EXT3_FEATURE_INCOMPAT_JOURNAL_DEV) { 204 fs->group_desc_count = 0; 205 ext2fs_mark_super_dirty(fs); 206 *ret_fs = fs; 207 return 0; 208 } 209 210 retry: 211 fs->group_desc_count = ext2fs_div_ceil(super->s_blocks_count - 212 super->s_first_data_block, 213 EXT2_BLOCKS_PER_GROUP(super)); 214 if (fs->group_desc_count == 0) { 215 retval = EXT2_ET_TOOSMALL; 216 goto cleanup; 217 } 218 fs->desc_blocks = ext2fs_div_ceil(fs->group_desc_count, 219 EXT2_DESC_PER_BLOCK(super)); 220 221 i = fs->blocksize >= 4096 ? 1 : 4096 / fs->blocksize; 222 set_field(s_inodes_count, super->s_blocks_count / i); 223 224 /* 225 * Make sure we have at least EXT2_FIRST_INO + 1 inodes, so 226 * that we have enough inodes for the filesystem(!) 227 */ 228 if (super->s_inodes_count < EXT2_FIRST_INODE(super)+1) 229 super->s_inodes_count = EXT2_FIRST_INODE(super)+1; 230 231 /* 232 * There should be at least as many inodes as the user 233 * requested. Figure out how many inodes per group that 234 * should be. But make sure that we don't allocate more than 235 * one bitmap's worth of inodes each group. 236 */ 237 ipg = ext2fs_div_ceil(super->s_inodes_count, fs->group_desc_count); 238 if (ipg > fs->blocksize * 8) { 239 if (super->s_blocks_per_group >= 256) { 240 /* Try again with slightly different parameters */ 241 super->s_blocks_per_group -= 8; 242 super->s_blocks_count = param->s_blocks_count; 243 super->s_frags_per_group = super->s_blocks_per_group * 244 frags_per_block; 245 goto retry; 246 } else 247 return EXT2_ET_TOO_MANY_INODES; 248 } 249 250 if (ipg > (unsigned) EXT2_MAX_INODES_PER_GROUP(super)) 251 ipg = EXT2_MAX_INODES_PER_GROUP(super); 252 253 ipg_retry: 254 super->s_inodes_per_group = ipg; 255 256 /* 257 * Make sure the number of inodes per group completely fills 258 * the inode table blocks in the descriptor. If not, add some 259 * additional inodes/group. Waste not, want not... 260 */ 261 fs->inode_blocks_per_group = (((super->s_inodes_per_group * 262 EXT2_INODE_SIZE(super)) + 263 EXT2_BLOCK_SIZE(super) - 1) / 264 EXT2_BLOCK_SIZE(super)); 265 super->s_inodes_per_group = ((fs->inode_blocks_per_group * 266 EXT2_BLOCK_SIZE(super)) / 267 EXT2_INODE_SIZE(super)); 268 /* 269 * Finally, make sure the number of inodes per group is a 270 * multiple of 8. This is needed to simplify the bitmap 271 * splicing code. 272 */ 273 super->s_inodes_per_group &= ~7; 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)); 278 279 /* 280 * adjust inode count to reflect the adjusted inodes_per_group 281 */ 282 if ((__u64)super->s_inodes_per_group * fs->group_desc_count > ~0U) { 283 ipg--; 284 goto ipg_retry; 285 } 286 super->s_inodes_count = super->s_inodes_per_group * 287 fs->group_desc_count; 288 super->s_free_inodes_count = super->s_inodes_count; 289 290 /* 291 * check the number of reserved group descriptor table blocks 292 */ 293 if (super->s_feature_compat & EXT2_FEATURE_COMPAT_RESIZE_INODE) 294 rsv_gdt = calc_reserved_gdt_blocks(fs); 295 else 296 rsv_gdt = 0; 297 set_field(s_reserved_gdt_blocks, rsv_gdt); 298 if (super->s_reserved_gdt_blocks > EXT2_ADDR_PER_BLOCK(super)) { 299 retval = EXT2_ET_RES_GDT_BLOCKS; 300 goto cleanup; 301 } 302 303 /* 304 * Calculate the maximum number of bookkeeping blocks per 305 * group. It includes the superblock, the block group 306 * descriptors, the block bitmap, the inode bitmap, the inode 307 * table, and the reserved gdt blocks. 308 */ 309 overhead = (int) (3 + fs->inode_blocks_per_group + 310 fs->desc_blocks + super->s_reserved_gdt_blocks); 311 312 /* This can only happen if the user requested too many inodes */ 313 if (overhead > super->s_blocks_per_group) 314 return EXT2_ET_TOO_MANY_INODES; 315 316 /* 317 * See if the last group is big enough to support the 318 * necessary data structures. If not, we need to get rid of 319 * it. We need to recalculate the overhead for the last block 320 * group, since it might or might not have a superblock 321 * backup. 322 */ 323 overhead = (int) (2 + fs->inode_blocks_per_group); 324 if (ext2fs_bg_has_super(fs, fs->group_desc_count - 1)) 325 overhead += 1 + fs->desc_blocks + super->s_reserved_gdt_blocks; 326 rem = ((super->s_blocks_count - super->s_first_data_block) % 327 super->s_blocks_per_group); 328 if ((fs->group_desc_count == 1) && rem && (rem < overhead)) 329 return EXT2_ET_TOOSMALL; 330 if (rem && (rem < overhead+50)) { 331 super->s_blocks_count -= rem; 332 goto retry; 333 } 334 335 /* 336 * At this point we know how big the filesystem will be. So 337 * we can do any and all allocations that depend on the block 338 * count. 339 */ 340 341 retval = ext2fs_get_mem(strlen(fs->device_name) + 80, &buf); 342 if (retval) 343 goto cleanup; 344 345 sprintf(buf, "block bitmap for %s", fs->device_name); 346 retval = ext2fs_allocate_block_bitmap(fs, buf, &fs->block_map); 347 if (retval) 348 goto cleanup; 349 350 sprintf(buf, "inode bitmap for %s", fs->device_name); 351 retval = ext2fs_allocate_inode_bitmap(fs, buf, &fs->inode_map); 352 if (retval) 353 goto cleanup; 354 355 ext2fs_free_mem(&buf); 356 357 retval = ext2fs_get_array(fs->desc_blocks, fs->blocksize, 358 &fs->group_desc); 359 if (retval) 360 goto cleanup; 361 362 memset(fs->group_desc, 0, (size_t) fs->desc_blocks * fs->blocksize); 363 364 /* 365 * Reserve the superblock and group descriptors for each 366 * group, and fill in the correct group statistics for group. 367 * Note that although the block bitmap, inode bitmap, and 368 * inode table have not been allocated (and in fact won't be 369 * by this routine), they are accounted for nevertheless. 370 */ 371 super->s_free_blocks_count = 0; 372 for (i = 0; i < fs->group_desc_count; i++) { 373 numblocks = ext2fs_reserve_super_and_bgd(fs, i, fs->block_map); 374 375 super->s_free_blocks_count += numblocks; 376 fs->group_desc[i].bg_free_blocks_count = numblocks; 377 fs->group_desc[i].bg_free_inodes_count = 378 fs->super->s_inodes_per_group; 379 fs->group_desc[i].bg_used_dirs_count = 0; 380 } 381 382 c = (char) 255; 383 if (((int) c) == -1) { 384 super->s_flags |= EXT2_FLAGS_SIGNED_HASH; 385 } else { 386 super->s_flags |= EXT2_FLAGS_UNSIGNED_HASH; 387 } 388 389 ext2fs_mark_super_dirty(fs); 390 ext2fs_mark_bb_dirty(fs); 391 ext2fs_mark_ib_dirty(fs); 392 393 io_channel_set_blksize(fs->io, fs->blocksize); 394 395 *ret_fs = fs; 396 return 0; 397 cleanup: 398 ext2fs_free(fs); 399 return retval; 400 } 401
