initialize.c revision f335864338a6fbce8134a445ffdd0cdeb3f3f1bc
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 = 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 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 io_flags; 107 char *buf; 108 109 if (!param || !param->s_blocks_count) 110 return EXT2_ET_INVALID_ARGUMENT; 111 112 retval = ext2fs_get_mem(sizeof(struct struct_ext2_filsys), &fs); 113 if (retval) 114 return retval; 115 116 memset(fs, 0, sizeof(struct struct_ext2_filsys)); 117 fs->magic = EXT2_ET_MAGIC_EXT2FS_FILSYS; 118 fs->flags = flags | EXT2_FLAG_RW; 119 fs->umask = 022; 120#ifdef WORDS_BIGENDIAN 121 fs->flags |= EXT2_FLAG_SWAP_BYTES; 122#endif 123 io_flags = IO_FLAG_RW; 124 if (flags & EXT2_FLAG_EXCLUSIVE) 125 io_flags |= IO_FLAG_EXCLUSIVE; 126 retval = manager->open(name, io_flags, &fs->io); 127 if (retval) 128 goto cleanup; 129 fs->image_io = fs->io; 130 fs->io->app_data = fs; 131 retval = ext2fs_get_mem(strlen(name)+1, &fs->device_name); 132 if (retval) 133 goto cleanup; 134 135 strcpy(fs->device_name, name); 136 retval = ext2fs_get_mem(SUPERBLOCK_SIZE, &super); 137 if (retval) 138 goto cleanup; 139 fs->super = super; 140 141 memset(super, 0, SUPERBLOCK_SIZE); 142 143#define set_field(field, default) (super->field = param->field ? \ 144 param->field : (default)) 145 146 super->s_magic = EXT2_SUPER_MAGIC; 147 super->s_state = EXT2_VALID_FS; 148 149 set_field(s_log_block_size, 0); /* default blocksize: 1024 bytes */ 150 set_field(s_log_frag_size, 0); /* default fragsize: 1024 bytes */ 151 set_field(s_first_data_block, super->s_log_block_size ? 0 : 1); 152 set_field(s_max_mnt_count, EXT2_DFL_MAX_MNT_COUNT); 153 set_field(s_errors, EXT2_ERRORS_DEFAULT); 154 set_field(s_feature_compat, 0); 155 set_field(s_feature_incompat, 0); 156 set_field(s_feature_ro_compat, 0); 157 set_field(s_first_meta_bg, 0); 158 if (super->s_feature_incompat & ~EXT2_LIB_FEATURE_INCOMPAT_SUPP) { 159 retval = EXT2_ET_UNSUPP_FEATURE; 160 goto cleanup; 161 } 162 if (super->s_feature_ro_compat & ~EXT2_LIB_FEATURE_RO_COMPAT_SUPP) { 163 retval = EXT2_ET_RO_UNSUPP_FEATURE; 164 goto cleanup; 165 } 166 167 set_field(s_rev_level, EXT2_GOOD_OLD_REV); 168 if (super->s_rev_level >= EXT2_DYNAMIC_REV) { 169 set_field(s_first_ino, EXT2_GOOD_OLD_FIRST_INO); 170 set_field(s_inode_size, EXT2_GOOD_OLD_INODE_SIZE); 171 } 172 173 set_field(s_checkinterval, EXT2_DFL_CHECKINTERVAL); 174 super->s_mkfs_time = super->s_lastcheck = fs->now ? fs->now : time(NULL); 175 176 super->s_creator_os = CREATOR_OS; 177 178 fs->blocksize = EXT2_BLOCK_SIZE(super); 179 fs->fragsize = EXT2_FRAG_SIZE(super); 180 frags_per_block = fs->blocksize / fs->fragsize; 181 182 /* default: (fs->blocksize*8) blocks/group, up to 2^16 (GDT limit) */ 183 set_field(s_blocks_per_group, fs->blocksize * 8); 184 if (super->s_blocks_per_group > EXT2_MAX_BLOCKS_PER_GROUP(super)) 185 super->s_blocks_per_group = EXT2_MAX_BLOCKS_PER_GROUP(super); 186 super->s_frags_per_group = super->s_blocks_per_group * frags_per_block; 187 188 super->s_blocks_count = param->s_blocks_count; 189 super->s_r_blocks_count = param->s_r_blocks_count; 190 if (super->s_r_blocks_count >= param->s_blocks_count) { 191 retval = EXT2_ET_INVALID_ARGUMENT; 192 goto cleanup; 193 } 194 195 /* 196 * If we're creating an external journal device, we don't need 197 * to bother with the rest. 198 */ 199 if (super->s_feature_incompat & EXT3_FEATURE_INCOMPAT_JOURNAL_DEV) { 200 fs->group_desc_count = 0; 201 ext2fs_mark_super_dirty(fs); 202 *ret_fs = fs; 203 return 0; 204 } 205 206retry: 207 fs->group_desc_count = ext2fs_div_ceil(super->s_blocks_count - 208 super->s_first_data_block, 209 EXT2_BLOCKS_PER_GROUP(super)); 210 if (fs->group_desc_count == 0) { 211 retval = EXT2_ET_TOOSMALL; 212 goto cleanup; 213 } 214 fs->desc_blocks = ext2fs_div_ceil(fs->group_desc_count, 215 EXT2_DESC_PER_BLOCK(super)); 216 217 i = fs->blocksize >= 4096 ? 1 : 4096 / fs->blocksize; 218 set_field(s_inodes_count, super->s_blocks_count / i); 219 220 /* 221 * Make sure we have at least EXT2_FIRST_INO + 1 inodes, so 222 * that we have enough inodes for the filesystem(!) 223 */ 224 if (super->s_inodes_count < EXT2_FIRST_INODE(super)+1) 225 super->s_inodes_count = EXT2_FIRST_INODE(super)+1; 226 227 /* 228 * There should be at least as many inodes as the user 229 * requested. Figure out how many inodes per group that 230 * should be. But make sure that we don't allocate more than 231 * one bitmap's worth of inodes each group. 232 */ 233 ipg = ext2fs_div_ceil(super->s_inodes_count, fs->group_desc_count); 234 if (ipg > fs->blocksize * 8) { 235 if (super->s_blocks_per_group >= 256) { 236 /* Try again with slightly different parameters */ 237 super->s_blocks_per_group -= 8; 238 super->s_blocks_count = param->s_blocks_count; 239 super->s_frags_per_group = super->s_blocks_per_group * 240 frags_per_block; 241 goto retry; 242 } else 243 return EXT2_ET_TOO_MANY_INODES; 244 } 245 246 if (ipg > (unsigned) EXT2_MAX_INODES_PER_GROUP(super)) 247 ipg = EXT2_MAX_INODES_PER_GROUP(super); 248 249ipg_retry: 250 super->s_inodes_per_group = ipg; 251 252 /* 253 * Make sure the number of inodes per group completely fills 254 * the inode table blocks in the descriptor. If not, add some 255 * additional inodes/group. Waste not, want not... 256 */ 257 fs->inode_blocks_per_group = (((super->s_inodes_per_group * 258 EXT2_INODE_SIZE(super)) + 259 EXT2_BLOCK_SIZE(super) - 1) / 260 EXT2_BLOCK_SIZE(super)); 261 super->s_inodes_per_group = ((fs->inode_blocks_per_group * 262 EXT2_BLOCK_SIZE(super)) / 263 EXT2_INODE_SIZE(super)); 264 /* 265 * Finally, make sure the number of inodes per group is a 266 * multiple of 8. This is needed to simplify the bitmap 267 * splicing code. 268 */ 269 super->s_inodes_per_group &= ~7; 270 fs->inode_blocks_per_group = (((super->s_inodes_per_group * 271 EXT2_INODE_SIZE(super)) + 272 EXT2_BLOCK_SIZE(super) - 1) / 273 EXT2_BLOCK_SIZE(super)); 274 275 /* 276 * adjust inode count to reflect the adjusted inodes_per_group 277 */ 278 if ((__u64)super->s_inodes_per_group * fs->group_desc_count > ~0U) { 279 ipg--; 280 goto ipg_retry; 281 } 282 super->s_inodes_count = super->s_inodes_per_group * 283 fs->group_desc_count; 284 super->s_free_inodes_count = super->s_inodes_count; 285 286 /* 287 * check the number of reserved group descriptor table blocks 288 */ 289 if (super->s_feature_compat & EXT2_FEATURE_COMPAT_RESIZE_INODE) 290 rsv_gdt = calc_reserved_gdt_blocks(fs); 291 else 292 rsv_gdt = 0; 293 set_field(s_reserved_gdt_blocks, rsv_gdt); 294 if (super->s_reserved_gdt_blocks > EXT2_ADDR_PER_BLOCK(super)) { 295 retval = EXT2_ET_RES_GDT_BLOCKS; 296 goto cleanup; 297 } 298 299 /* 300 * Overhead is the number of bookkeeping blocks per group. It 301 * includes the superblock backup, the group descriptor 302 * backups, the inode bitmap, the block bitmap, and the inode 303 * table. 304 */ 305 306 overhead = (int) (2 + fs->inode_blocks_per_group); 307 308 if (ext2fs_bg_has_super(fs, fs->group_desc_count - 1)) 309 overhead += 1 + fs->desc_blocks + super->s_reserved_gdt_blocks; 310 311 /* This can only happen if the user requested too many inodes */ 312 if (overhead > super->s_blocks_per_group) 313 return EXT2_ET_TOO_MANY_INODES; 314 315 /* 316 * See if the last group is big enough to support the 317 * necessary data structures. If not, we need to get rid of 318 * it. 319 */ 320 rem = ((super->s_blocks_count - super->s_first_data_block) % 321 super->s_blocks_per_group); 322 if ((fs->group_desc_count == 1) && rem && (rem < overhead)) 323 return EXT2_ET_TOOSMALL; 324 if (rem && (rem < overhead+50)) { 325 super->s_blocks_count -= rem; 326 goto retry; 327 } 328 329 /* 330 * At this point we know how big the filesystem will be. So 331 * we can do any and all allocations that depend on the block 332 * count. 333 */ 334 335 retval = ext2fs_get_mem(strlen(fs->device_name) + 80, &buf); 336 if (retval) 337 goto cleanup; 338 339 sprintf(buf, "block bitmap for %s", fs->device_name); 340 retval = ext2fs_allocate_block_bitmap(fs, buf, &fs->block_map); 341 if (retval) 342 goto cleanup; 343 344 sprintf(buf, "inode bitmap for %s", fs->device_name); 345 retval = ext2fs_allocate_inode_bitmap(fs, buf, &fs->inode_map); 346 if (retval) 347 goto cleanup; 348 349 ext2fs_free_mem(&buf); 350 351 retval = ext2fs_get_mem((size_t) fs->desc_blocks * fs->blocksize, 352 &fs->group_desc); 353 if (retval) 354 goto cleanup; 355 356 memset(fs->group_desc, 0, (size_t) fs->desc_blocks * fs->blocksize); 357 358 /* 359 * Reserve the superblock and group descriptors for each 360 * group, and fill in the correct group statistics for group. 361 * Note that although the block bitmap, inode bitmap, and 362 * inode table have not been allocated (and in fact won't be 363 * by this routine), they are accounted for nevertheless. 364 */ 365 super->s_free_blocks_count = 0; 366 for (i = 0; i < fs->group_desc_count; i++) { 367 numblocks = ext2fs_reserve_super_and_bgd(fs, i, fs->block_map); 368 369 super->s_free_blocks_count += numblocks; 370 fs->group_desc[i].bg_free_blocks_count = numblocks; 371 fs->group_desc[i].bg_free_inodes_count = 372 fs->super->s_inodes_per_group; 373 fs->group_desc[i].bg_used_dirs_count = 0; 374 } 375 376 ext2fs_mark_super_dirty(fs); 377 ext2fs_mark_bb_dirty(fs); 378 ext2fs_mark_ib_dirty(fs); 379 380 io_channel_set_blksize(fs->io, fs->blocksize); 381 382 *ret_fs = fs; 383 return 0; 384cleanup: 385 ext2fs_free(fs); 386 return retval; 387} 388