initialize.c revision 39c47ce6417b81aa74596fd0d4d98d542525a444
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 = (max_blocks - sb->s_first_data_block + bpg - 1) / bpg; 81 rsv_gdb = (rsv_groups + gdpb - 1) / 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 blk_t group_block; 103 unsigned int ipg; 104 dgrp_t i; 105 blk_t numblocks; 106 int rsv_gdt; 107 int io_flags; 108 char *buf; 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 if (super->s_feature_incompat & ~EXT2_LIB_FEATURE_INCOMPAT_SUPP) { 160 retval = EXT2_ET_UNSUPP_FEATURE; 161 goto cleanup; 162 } 163 if (super->s_feature_ro_compat & ~EXT2_LIB_FEATURE_RO_COMPAT_SUPP) { 164 retval = EXT2_ET_RO_UNSUPP_FEATURE; 165 goto cleanup; 166 } 167 168 set_field(s_rev_level, EXT2_GOOD_OLD_REV); 169 if (super->s_rev_level >= EXT2_DYNAMIC_REV) { 170 set_field(s_first_ino, EXT2_GOOD_OLD_FIRST_INO); 171 set_field(s_inode_size, EXT2_GOOD_OLD_INODE_SIZE); 172 } 173 174 set_field(s_checkinterval, EXT2_DFL_CHECKINTERVAL); 175 super->s_mkfs_time = super->s_lastcheck = fs->now ? fs->now : time(NULL); 176 177 super->s_creator_os = CREATOR_OS; 178 179 fs->blocksize = EXT2_BLOCK_SIZE(super); 180 fs->fragsize = EXT2_FRAG_SIZE(super); 181 frags_per_block = fs->blocksize / fs->fragsize; 182 183 /* default: (fs->blocksize*8) blocks/group, up to 2^16 (GDT limit) */ 184 set_field(s_blocks_per_group, fs->blocksize * 8); 185 if (super->s_blocks_per_group > EXT2_MAX_BLOCKS_PER_GROUP(super)) 186 super->s_blocks_per_group = EXT2_MAX_BLOCKS_PER_GROUP(super); 187 super->s_frags_per_group = super->s_blocks_per_group * frags_per_block; 188 189 super->s_blocks_count = param->s_blocks_count; 190 super->s_r_blocks_count = param->s_r_blocks_count; 191 if (super->s_r_blocks_count >= param->s_blocks_count) { 192 retval = EXT2_ET_INVALID_ARGUMENT; 193 goto cleanup; 194 } 195 196 /* 197 * If we're creating an external journal device, we don't need 198 * to bother with the rest. 199 */ 200 if (super->s_feature_incompat & EXT3_FEATURE_INCOMPAT_JOURNAL_DEV) { 201 fs->group_desc_count = 0; 202 ext2fs_mark_super_dirty(fs); 203 *ret_fs = fs; 204 return 0; 205 } 206 207retry: 208 fs->group_desc_count = (super->s_blocks_count - 209 super->s_first_data_block + 210 EXT2_BLOCKS_PER_GROUP(super) - 1) 211 / EXT2_BLOCKS_PER_GROUP(super); 212 if (fs->group_desc_count == 0) { 213 retval = EXT2_ET_TOOSMALL; 214 goto cleanup; 215 } 216 fs->desc_blocks = (fs->group_desc_count + 217 EXT2_DESC_PER_BLOCK(super) - 1) 218 / EXT2_DESC_PER_BLOCK(super); 219 220 i = fs->blocksize >= 4096 ? 1 : 4096 / fs->blocksize; 221 set_field(s_inodes_count, super->s_blocks_count / i); 222 223 /* 224 * Make sure we have at least EXT2_FIRST_INO + 1 inodes, so 225 * that we have enough inodes for the filesystem(!) 226 */ 227 if (super->s_inodes_count < EXT2_FIRST_INODE(super)+1) 228 super->s_inodes_count = EXT2_FIRST_INODE(super)+1; 229 230 /* 231 * There should be at least as many inodes as the user 232 * requested. Figure out how many inodes per group that 233 * should be. But make sure that we don't allocate more than 234 * one bitmap's worth of inodes each group. 235 */ 236 ipg = (super->s_inodes_count + fs->group_desc_count - 1) / 237 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 super->s_inodes_per_group = ipg; 254 if (super->s_inodes_count > ipg * fs->group_desc_count) 255 super->s_inodes_count = ipg * fs->group_desc_count; 256 257 /* 258 * Make sure the number of inodes per group completely fills 259 * the inode table blocks in the descriptor. If not, add some 260 * additional inodes/group. Waste not, want not... 261 */ 262 fs->inode_blocks_per_group = (((super->s_inodes_per_group * 263 EXT2_INODE_SIZE(super)) + 264 EXT2_BLOCK_SIZE(super) - 1) / 265 EXT2_BLOCK_SIZE(super)); 266 super->s_inodes_per_group = ((fs->inode_blocks_per_group * 267 EXT2_BLOCK_SIZE(super)) / 268 EXT2_INODE_SIZE(super)); 269 /* 270 * Finally, make sure the number of inodes per group is a 271 * multiple of 8. This is needed to simplify the bitmap 272 * splicing code. 273 */ 274 super->s_inodes_per_group &= ~7; 275 fs->inode_blocks_per_group = (((super->s_inodes_per_group * 276 EXT2_INODE_SIZE(super)) + 277 EXT2_BLOCK_SIZE(super) - 1) / 278 EXT2_BLOCK_SIZE(super)); 279 280 /* 281 * adjust inode count to reflect the adjusted inodes_per_group 282 */ 283 super->s_inodes_count = super->s_inodes_per_group * 284 fs->group_desc_count; 285 super->s_free_inodes_count = super->s_inodes_count; 286 287 /* 288 * check the number of reserved group descriptor table blocks 289 */ 290 if (super->s_feature_compat & EXT2_FEATURE_COMPAT_RESIZE_INODE) 291 rsv_gdt = calc_reserved_gdt_blocks(fs); 292 else 293 rsv_gdt = 0; 294 set_field(s_reserved_gdt_blocks, rsv_gdt); 295 if (super->s_reserved_gdt_blocks > EXT2_ADDR_PER_BLOCK(super)) { 296 retval = EXT2_ET_RES_GDT_BLOCKS; 297 goto cleanup; 298 } 299 300 /* 301 * Overhead is the number of bookkeeping blocks per group. It 302 * includes the superblock backup, the group descriptor 303 * backups, the inode bitmap, the block bitmap, and the inode 304 * table. 305 */ 306 307 overhead = (int) (2 + fs->inode_blocks_per_group); 308 309 if (ext2fs_bg_has_super(fs, fs->group_desc_count - 1)) 310 overhead += 1 + 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. 320 */ 321 rem = ((super->s_blocks_count - super->s_first_data_block) % 322 super->s_blocks_per_group); 323 if ((fs->group_desc_count == 1) && rem && (rem < overhead)) 324 return EXT2_ET_TOOSMALL; 325 if (rem && (rem < overhead+50)) { 326 super->s_blocks_count -= rem; 327 goto retry; 328 } 329 330 /* 331 * At this point we know how big the filesystem will be. So 332 * we can do any and all allocations that depend on the block 333 * count. 334 */ 335 336 retval = ext2fs_get_mem(strlen(fs->device_name) + 80, &buf); 337 if (retval) 338 goto cleanup; 339 340 sprintf(buf, "block bitmap for %s", fs->device_name); 341 retval = ext2fs_allocate_block_bitmap(fs, buf, &fs->block_map); 342 if (retval) 343 goto cleanup; 344 345 sprintf(buf, "inode bitmap for %s", fs->device_name); 346 retval = ext2fs_allocate_inode_bitmap(fs, buf, &fs->inode_map); 347 if (retval) 348 goto cleanup; 349 350 ext2fs_free_mem(&buf); 351 352 retval = ext2fs_get_mem((size_t) fs->desc_blocks * fs->blocksize, 353 &fs->group_desc); 354 if (retval) 355 goto cleanup; 356 357 memset(fs->group_desc, 0, (size_t) fs->desc_blocks * fs->blocksize); 358 359 /* 360 * Reserve the superblock and group descriptors for each 361 * group, and fill in the correct group statistics for group. 362 * Note that although the block bitmap, inode bitmap, and 363 * inode table have not been allocated (and in fact won't be 364 * by this routine), they are accounted for nevertheless. 365 */ 366 group_block = super->s_first_data_block; 367 super->s_free_blocks_count = 0; 368 for (i = 0; i < fs->group_desc_count; i++) { 369 numblocks = ext2fs_reserve_super_and_bgd(fs, i, fs->block_map); 370 371 super->s_free_blocks_count += numblocks; 372 fs->group_desc[i].bg_free_blocks_count = numblocks; 373 fs->group_desc[i].bg_free_inodes_count = 374 fs->super->s_inodes_per_group; 375 fs->group_desc[i].bg_used_dirs_count = 0; 376 377 group_block += super->s_blocks_per_group; 378 } 379 380 ext2fs_mark_super_dirty(fs); 381 ext2fs_mark_bb_dirty(fs); 382 ext2fs_mark_ib_dirty(fs); 383 384 io_channel_set_blksize(fs->io, fs->blocksize); 385 386 *ret_fs = fs; 387 return 0; 388cleanup: 389 ext2fs_free(fs); 390 return retval; 391} 392