1/* vi: set sw=4 ts=4: */ 2/* 3 * initialize.c --- initialize a filesystem handle given superblock 4 * parameters. Used by mke2fs when initializing a filesystem. 5 * 6 * Copyright (C) 1994, 1995, 1996 Theodore Ts'o. 7 * 8 * %Begin-Header% 9 * This file may be redistributed under the terms of the GNU Public 10 * License. 11 * %End-Header% 12 */ 13 14#include <stdio.h> 15#include <string.h> 16#if HAVE_UNISTD_H 17#include <unistd.h> 18#endif 19#include <fcntl.h> 20#include <time.h> 21#if HAVE_SYS_STAT_H 22#include <sys/stat.h> 23#endif 24#if HAVE_SYS_TYPES_H 25#include <sys/types.h> 26#endif 27 28#include "ext2_fs.h" 29#include "ext2fs.h" 30 31#if defined(__linux__) && defined(EXT2_OS_LINUX) 32#define CREATOR_OS EXT2_OS_LINUX 33#else 34#if defined(__GNU__) && defined(EXT2_OS_HURD) 35#define CREATOR_OS EXT2_OS_HURD 36#else 37#if defined(__FreeBSD__) && defined(EXT2_OS_FREEBSD) 38#define CREATOR_OS EXT2_OS_FREEBSD 39#else 40#if defined(LITES) && defined(EXT2_OS_LITES) 41#define CREATOR_OS EXT2_OS_LITES 42#else 43#define CREATOR_OS EXT2_OS_LINUX /* by default */ 44#endif /* defined(LITES) && defined(EXT2_OS_LITES) */ 45#endif /* defined(__FreeBSD__) && defined(EXT2_OS_FREEBSD) */ 46#endif /* defined(__GNU__) && defined(EXT2_OS_HURD) */ 47#endif /* defined(__linux__) && defined(EXT2_OS_LINUX) */ 48 49/* 50 * Note we override the kernel include file's idea of what the default 51 * check interval (never) should be. It's a good idea to check at 52 * least *occasionally*, specially since servers will never rarely get 53 * to reboot, since Linux is so robust these days. :-) 54 * 55 * 180 days (six months) seems like a good value. 56 */ 57#ifdef EXT2_DFL_CHECKINTERVAL 58#undef EXT2_DFL_CHECKINTERVAL 59#endif 60#define EXT2_DFL_CHECKINTERVAL (86400L * 180L) 61 62/* 63 * Calculate the number of GDT blocks to reserve for online filesystem growth. 64 * The absolute maximum number of GDT blocks we can reserve is determined by 65 * the number of block pointers that can fit into a single block. 66 */ 67static int calc_reserved_gdt_blocks(ext2_filsys fs) 68{ 69 struct ext2_super_block *sb = fs->super; 70 unsigned long bpg = sb->s_blocks_per_group; 71 unsigned int gdpb = fs->blocksize / sizeof(struct ext2_group_desc); 72 unsigned long max_blocks = 0xffffffff; 73 unsigned long rsv_groups; 74 int rsv_gdb; 75 76 /* We set it at 1024x the current filesystem size, or 77 * the upper block count limit (2^32), whichever is lower. 78 */ 79 if (sb->s_blocks_count < max_blocks / 1024) 80 max_blocks = sb->s_blocks_count * 1024; 81 rsv_groups = (max_blocks - sb->s_first_data_block + bpg - 1) / bpg; 82 rsv_gdb = (rsv_groups + gdpb - 1) / gdpb - fs->desc_blocks; 83 if (rsv_gdb > EXT2_ADDR_PER_BLOCK(sb)) 84 rsv_gdb = EXT2_ADDR_PER_BLOCK(sb); 85#ifdef RES_GDT_DEBUG 86 printf("max_blocks %lu, rsv_groups = %lu, rsv_gdb = %lu\n", 87 max_blocks, rsv_groups, rsv_gdb); 88#endif 89 90 return rsv_gdb; 91} 92 93errcode_t ext2fs_initialize(const char *name, int flags, 94 struct ext2_super_block *param, 95 io_manager manager, ext2_filsys *ret_fs) 96{ 97 ext2_filsys fs; 98 errcode_t retval; 99 struct ext2_super_block *super; 100 int frags_per_block; 101 unsigned int rem; 102 unsigned int overhead = 0; 103 blk_t group_block; 104 unsigned int ipg; 105 dgrp_t i; 106 blk_t numblocks; 107 int rsv_gdt; 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 retval = manager->open(name, IO_FLAG_RW, &fs->io); 125 if (retval) 126 goto cleanup; 127 fs->image_io = fs->io; 128 fs->io->app_data = fs; 129 retval = ext2fs_get_mem(strlen(name)+1, &fs->device_name); 130 if (retval) 131 goto cleanup; 132 133 strcpy(fs->device_name, name); 134 retval = ext2fs_get_mem(SUPERBLOCK_SIZE, &super); 135 if (retval) 136 goto cleanup; 137 fs->super = super; 138 139 memset(super, 0, SUPERBLOCK_SIZE); 140 141#define set_field(field, default) (super->field = param->field ? \ 142 param->field : (default)) 143 144 super->s_magic = EXT2_SUPER_MAGIC; 145 super->s_state = EXT2_VALID_FS; 146 147 set_field(s_log_block_size, 0); /* default blocksize: 1024 bytes */ 148 set_field(s_log_frag_size, 0); /* default fragsize: 1024 bytes */ 149 set_field(s_first_data_block, super->s_log_block_size ? 0 : 1); 150 set_field(s_max_mnt_count, EXT2_DFL_MAX_MNT_COUNT); 151 set_field(s_errors, EXT2_ERRORS_DEFAULT); 152 set_field(s_feature_compat, 0); 153 set_field(s_feature_incompat, 0); 154 set_field(s_feature_ro_compat, 0); 155 set_field(s_first_meta_bg, 0); 156 if (super->s_feature_incompat & ~EXT2_LIB_FEATURE_INCOMPAT_SUPP) { 157 retval = EXT2_ET_UNSUPP_FEATURE; 158 goto cleanup; 159 } 160 if (super->s_feature_ro_compat & ~EXT2_LIB_FEATURE_RO_COMPAT_SUPP) { 161 retval = EXT2_ET_RO_UNSUPP_FEATURE; 162 goto cleanup; 163 } 164 165 set_field(s_rev_level, EXT2_GOOD_OLD_REV); 166 if (super->s_rev_level >= EXT2_DYNAMIC_REV) { 167 set_field(s_first_ino, EXT2_GOOD_OLD_FIRST_INO); 168 set_field(s_inode_size, EXT2_GOOD_OLD_INODE_SIZE); 169 } 170 171 set_field(s_checkinterval, EXT2_DFL_CHECKINTERVAL); 172 super->s_mkfs_time = super->s_lastcheck = time(NULL); 173 174 super->s_creator_os = CREATOR_OS; 175 176 fs->blocksize = EXT2_BLOCK_SIZE(super); 177 fs->fragsize = EXT2_FRAG_SIZE(super); 178 frags_per_block = fs->blocksize / fs->fragsize; 179 180 /* default: (fs->blocksize*8) blocks/group, up to 2^16 (GDT limit) */ 181 set_field(s_blocks_per_group, fs->blocksize * 8); 182 if (super->s_blocks_per_group > EXT2_MAX_BLOCKS_PER_GROUP(super)) 183 super->s_blocks_per_group = EXT2_MAX_BLOCKS_PER_GROUP(super); 184 super->s_frags_per_group = super->s_blocks_per_group * frags_per_block; 185 186 super->s_blocks_count = param->s_blocks_count; 187 super->s_r_blocks_count = param->s_r_blocks_count; 188 if (super->s_r_blocks_count >= param->s_blocks_count) { 189 retval = EXT2_ET_INVALID_ARGUMENT; 190 goto cleanup; 191 } 192 193 /* 194 * If we're creating an external journal device, we don't need 195 * to bother with the rest. 196 */ 197 if (super->s_feature_incompat & EXT3_FEATURE_INCOMPAT_JOURNAL_DEV) { 198 fs->group_desc_count = 0; 199 ext2fs_mark_super_dirty(fs); 200 *ret_fs = fs; 201 return 0; 202 } 203 204retry: 205 fs->group_desc_count = (super->s_blocks_count - 206 super->s_first_data_block + 207 EXT2_BLOCKS_PER_GROUP(super) - 1) 208 / EXT2_BLOCKS_PER_GROUP(super); 209 if (fs->group_desc_count == 0) { 210 retval = EXT2_ET_TOOSMALL; 211 goto cleanup; 212 } 213 fs->desc_blocks = (fs->group_desc_count + 214 EXT2_DESC_PER_BLOCK(super) - 1) 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 = (super->s_inodes_count + fs->group_desc_count - 1) / 234 fs->group_desc_count; 235 if (ipg > fs->blocksize * 8) { 236 if (super->s_blocks_per_group >= 256) { 237 /* Try again with slightly different parameters */ 238 super->s_blocks_per_group -= 8; 239 super->s_blocks_count = param->s_blocks_count; 240 super->s_frags_per_group = super->s_blocks_per_group * 241 frags_per_block; 242 goto retry; 243 } else 244 return EXT2_ET_TOO_MANY_INODES; 245 } 246 247 if (ipg > (unsigned) EXT2_MAX_INODES_PER_GROUP(super)) 248 ipg = EXT2_MAX_INODES_PER_GROUP(super); 249 250 super->s_inodes_per_group = ipg; 251 if (super->s_inodes_count > ipg * fs->group_desc_count) 252 super->s_inodes_count = ipg * fs->group_desc_count; 253 254 /* 255 * Make sure the number of inodes per group completely fills 256 * the inode table blocks in the descriptor. If not, add some 257 * additional inodes/group. Waste not, want not... 258 */ 259 fs->inode_blocks_per_group = (((super->s_inodes_per_group * 260 EXT2_INODE_SIZE(super)) + 261 EXT2_BLOCK_SIZE(super) - 1) / 262 EXT2_BLOCK_SIZE(super)); 263 super->s_inodes_per_group = ((fs->inode_blocks_per_group * 264 EXT2_BLOCK_SIZE(super)) / 265 EXT2_INODE_SIZE(super)); 266 /* 267 * Finally, make sure the number of inodes per group is a 268 * multiple of 8. This is needed to simplify the bitmap 269 * splicing code. 270 */ 271 super->s_inodes_per_group &= ~7; 272 fs->inode_blocks_per_group = (((super->s_inodes_per_group * 273 EXT2_INODE_SIZE(super)) + 274 EXT2_BLOCK_SIZE(super) - 1) / 275 EXT2_BLOCK_SIZE(super)); 276 277 /* 278 * adjust inode count to reflect the adjusted inodes_per_group 279 */ 280 super->s_inodes_count = super->s_inodes_per_group * 281 fs->group_desc_count; 282 super->s_free_inodes_count = super->s_inodes_count; 283 284 /* 285 * check the number of reserved group descriptor table blocks 286 */ 287 if (super->s_feature_compat & EXT2_FEATURE_COMPAT_RESIZE_INODE) 288 rsv_gdt = calc_reserved_gdt_blocks(fs); 289 else 290 rsv_gdt = 0; 291 set_field(s_reserved_gdt_blocks, rsv_gdt); 292 if (super->s_reserved_gdt_blocks > EXT2_ADDR_PER_BLOCK(super)) { 293 retval = EXT2_ET_RES_GDT_BLOCKS; 294 goto cleanup; 295 } 296 297 /* 298 * Overhead is the number of bookkeeping blocks per group. It 299 * includes the superblock backup, the group descriptor 300 * backups, the inode bitmap, the block bitmap, and the inode 301 * table. 302 */ 303 304 overhead = (int) (2 + fs->inode_blocks_per_group); 305 306 if (ext2fs_bg_has_super(fs, fs->group_desc_count - 1)) 307 overhead += 1 + fs->desc_blocks + super->s_reserved_gdt_blocks; 308 309 /* This can only happen if the user requested too many inodes */ 310 if (overhead > super->s_blocks_per_group) 311 return EXT2_ET_TOO_MANY_INODES; 312 313 /* 314 * See if the last group is big enough to support the 315 * necessary data structures. If not, we need to get rid of 316 * it. 317 */ 318 rem = ((super->s_blocks_count - super->s_first_data_block) % 319 super->s_blocks_per_group); 320 if ((fs->group_desc_count == 1) && rem && (rem < overhead)) 321 return EXT2_ET_TOOSMALL; 322 if (rem && (rem < overhead+50)) { 323 super->s_blocks_count -= rem; 324 goto retry; 325 } 326 327 /* 328 * At this point we know how big the filesystem will be. So 329 * we can do any and all allocations that depend on the block 330 * count. 331 */ 332 333 retval = ext2fs_get_mem(strlen(fs->device_name) + 80, &buf); 334 if (retval) 335 goto cleanup; 336 337 sprintf(buf, "block bitmap for %s", fs->device_name); 338 retval = ext2fs_allocate_block_bitmap(fs, buf, &fs->block_map); 339 if (retval) 340 goto cleanup; 341 342 sprintf(buf, "inode bitmap for %s", fs->device_name); 343 retval = ext2fs_allocate_inode_bitmap(fs, buf, &fs->inode_map); 344 if (retval) 345 goto cleanup; 346 347 ext2fs_free_mem(&buf); 348 349 retval = ext2fs_get_mem((size_t) fs->desc_blocks * fs->blocksize, 350 &fs->group_desc); 351 if (retval) 352 goto cleanup; 353 354 memset(fs->group_desc, 0, (size_t) fs->desc_blocks * fs->blocksize); 355 356 /* 357 * Reserve the superblock and group descriptors for each 358 * group, and fill in the correct group statistics for group. 359 * Note that although the block bitmap, inode bitmap, and 360 * inode table have not been allocated (and in fact won't be 361 * by this routine), they are accounted for nevertheless. 362 */ 363 group_block = super->s_first_data_block; 364 super->s_free_blocks_count = 0; 365 for (i = 0; i < fs->group_desc_count; i++) { 366 numblocks = ext2fs_reserve_super_and_bgd(fs, i, fs->block_map); 367 368 super->s_free_blocks_count += numblocks; 369 fs->group_desc[i].bg_free_blocks_count = numblocks; 370 fs->group_desc[i].bg_free_inodes_count = 371 fs->super->s_inodes_per_group; 372 fs->group_desc[i].bg_used_dirs_count = 0; 373 374 group_block += super->s_blocks_per_group; 375 } 376 377 ext2fs_mark_super_dirty(fs); 378 ext2fs_mark_bb_dirty(fs); 379 ext2fs_mark_ib_dirty(fs); 380 381 io_channel_set_blksize(fs->io, fs->blocksize); 382 383 *ret_fs = fs; 384 return 0; 385cleanup: 386 ext2fs_free(fs); 387 return retval; 388} 389