initialize.c revision b21bf267783274683a432eea6e5c589eab94123e
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#elif defined(__GNU__) && defined(EXT2_OS_HURD) 33#define CREATOR_OS EXT2_OS_HURD 34#elif defined(__FreeBSD__) && defined(EXT2_OS_FREEBSD) 35#define CREATOR_OS EXT2_OS_FREEBSD 36#elif defined(LITES) && defined(EXT2_OS_LITES) 37#define CREATOR_OS EXT2_OS_LITES 38#else 39#define CREATOR_OS EXT2_OS_LINUX /* by default */ 40#endif 41 42/* 43 * Note we override the kernel include file's idea of what the default 44 * check interval (never) should be. It's a good idea to check at 45 * least *occasionally*, specially since servers will never rarely get 46 * to reboot, since Linux is so robust these days. :-) 47 * 48 * 180 days (six months) seems like a good value. 49 */ 50#ifdef EXT2_DFL_CHECKINTERVAL 51#undef EXT2_DFL_CHECKINTERVAL 52#endif 53#define EXT2_DFL_CHECKINTERVAL (86400L * 180L) 54 55errcode_t ext2fs_initialize(const char *name, int flags, 56 struct ext2_super_block *param, 57 io_manager manager, ext2_filsys *ret_fs) 58{ 59 ext2_filsys fs; 60 errcode_t retval; 61 struct ext2_super_block *super; 62 int frags_per_block; 63 int rem; 64 int overhead = 0; 65 blk_t group_block; 66 int ipg; 67 int i, j; 68 blk_t numblocks; 69 char *buf; 70 71 if (!param || !param->s_blocks_count) 72 return EXT2_ET_INVALID_ARGUMENT; 73 74 retval = ext2fs_get_mem(sizeof(struct struct_ext2_filsys), 75 (void **) &fs); 76 if (retval) 77 return retval; 78 79 memset(fs, 0, sizeof(struct struct_ext2_filsys)); 80 fs->magic = EXT2_ET_MAGIC_EXT2FS_FILSYS; 81 fs->flags = flags | EXT2_FLAG_RW; 82 fs->umask = 022; 83#ifdef WORDS_BIGENDIAN 84 fs->flags |= EXT2_FLAG_SWAP_BYTES; 85#endif 86 retval = manager->open(name, IO_FLAG_RW, &fs->io); 87 if (retval) 88 goto cleanup; 89 fs->io->app_data = fs; 90 retval = ext2fs_get_mem(strlen(name)+1, (void **) &fs->device_name); 91 if (retval) 92 goto cleanup; 93 94 strcpy(fs->device_name, name); 95 retval = ext2fs_get_mem(SUPERBLOCK_SIZE, (void **) &super); 96 if (retval) 97 goto cleanup; 98 fs->super = super; 99 100 memset(super, 0, SUPERBLOCK_SIZE); 101 102#define set_field(field, default) (super->field = param->field ? \ 103 param->field : (default)) 104 105 super->s_magic = EXT2_SUPER_MAGIC; 106 super->s_state = EXT2_VALID_FS; 107 108 set_field(s_log_block_size, 0); /* default blocksize: 1024 bytes */ 109 set_field(s_log_frag_size, 0); /* default fragsize: 1024 bytes */ 110 set_field(s_first_data_block, super->s_log_block_size ? 0 : 1); 111 set_field(s_max_mnt_count, EXT2_DFL_MAX_MNT_COUNT); 112 set_field(s_errors, EXT2_ERRORS_DEFAULT); 113 set_field(s_feature_compat, 0); 114 set_field(s_feature_incompat, 0); 115 set_field(s_feature_ro_compat, 0); 116 if (super->s_feature_incompat & ~EXT2_LIB_FEATURE_INCOMPAT_SUPP) 117 return EXT2_ET_UNSUPP_FEATURE; 118 if (super->s_feature_ro_compat & ~EXT2_LIB_FEATURE_RO_COMPAT_SUPP) 119 return EXT2_ET_RO_UNSUPP_FEATURE; 120 121 set_field(s_rev_level, EXT2_GOOD_OLD_REV); 122 if (super->s_rev_level >= EXT2_DYNAMIC_REV) { 123 set_field(s_first_ino, EXT2_GOOD_OLD_FIRST_INO); 124 set_field(s_inode_size, EXT2_GOOD_OLD_INODE_SIZE); 125 } 126 127 set_field(s_checkinterval, EXT2_DFL_CHECKINTERVAL); 128 super->s_lastcheck = time(NULL); 129 130 super->s_creator_os = CREATOR_OS; 131 132 fs->blocksize = EXT2_BLOCK_SIZE(super); 133 fs->fragsize = EXT2_FRAG_SIZE(super); 134 frags_per_block = fs->blocksize / fs->fragsize; 135 136 /* default: (fs->blocksize*8) blocks/group, up to 2^16 (GDT limit) */ 137 set_field(s_blocks_per_group, fs->blocksize * 8); 138 if (super->s_blocks_per_group > EXT2_MAX_BLOCKS_PER_GROUP(super)) 139 super->s_blocks_per_group = EXT2_MAX_BLOCKS_PER_GROUP(super); 140 super->s_frags_per_group = super->s_blocks_per_group * frags_per_block; 141 142 super->s_blocks_count = param->s_blocks_count; 143 super->s_r_blocks_count = param->s_r_blocks_count; 144 if (super->s_r_blocks_count >= param->s_blocks_count) { 145 retval = EXT2_ET_INVALID_ARGUMENT; 146 goto cleanup; 147 } 148 149 /* 150 * If we're creating an external journal device, we don't need 151 * to bother with the rest. 152 */ 153 if (super->s_feature_incompat & 154 EXT3_FEATURE_INCOMPAT_JOURNAL_DEV) { 155 fs->group_desc_count = 0; 156 ext2fs_mark_super_dirty(fs); 157 *ret_fs = fs; 158 return 0; 159 } 160 161retry: 162 fs->group_desc_count = (super->s_blocks_count - 163 super->s_first_data_block + 164 EXT2_BLOCKS_PER_GROUP(super) - 1) 165 / EXT2_BLOCKS_PER_GROUP(super); 166 if (fs->group_desc_count == 0) 167 return EXT2_ET_TOOSMALL; 168 fs->desc_blocks = (fs->group_desc_count + 169 EXT2_DESC_PER_BLOCK(super) - 1) 170 / EXT2_DESC_PER_BLOCK(super); 171 172 i = fs->blocksize >= 4096 ? 1 : 4096 / fs->blocksize; 173 set_field(s_inodes_count, super->s_blocks_count / i); 174 175 /* 176 * Make sure we have at least EXT2_FIRST_INO + 1 inodes, so 177 * that we have enough inodes for the filesystem(!) 178 */ 179 if (super->s_inodes_count < EXT2_FIRST_INODE(super)+1) 180 super->s_inodes_count = EXT2_FIRST_INODE(super)+1; 181 182 /* 183 * There should be at least as many inodes as the user 184 * requested. Figure out how many inodes per group that 185 * should be. But make sure that we don't allocate more than 186 * one bitmap's worth of inodes each group. 187 */ 188 ipg = (super->s_inodes_count + fs->group_desc_count - 1) / 189 fs->group_desc_count; 190 if (ipg > fs->blocksize * 8) 191 ipg = fs->blocksize * 8; 192 193 if (ipg > EXT2_MAX_INODES_PER_GROUP(super)) 194 ipg = EXT2_MAX_INODES_PER_GROUP(super); 195 196 super->s_inodes_per_group = ipg; 197 if (super->s_inodes_count > ipg * fs->group_desc_count) 198 super->s_inodes_count = ipg * fs->group_desc_count; 199 200 /* 201 * Make sure the number of inodes per group completely fills 202 * the inode table blocks in the descriptor. If not, add some 203 * additional inodes/group. Waste not, want not... 204 */ 205 fs->inode_blocks_per_group = (((super->s_inodes_per_group * 206 EXT2_INODE_SIZE(super)) + 207 EXT2_BLOCK_SIZE(super) - 1) / 208 EXT2_BLOCK_SIZE(super)); 209 super->s_inodes_per_group = ((fs->inode_blocks_per_group * 210 EXT2_BLOCK_SIZE(super)) / 211 EXT2_INODE_SIZE(super)); 212 /* 213 * Finally, make sure the number of inodes per group is a 214 * multiple of 8. This is needed to simplify the bitmap 215 * splicing code. 216 */ 217 super->s_inodes_per_group &= ~7; 218 fs->inode_blocks_per_group = (((super->s_inodes_per_group * 219 EXT2_INODE_SIZE(super)) + 220 EXT2_BLOCK_SIZE(super) - 1) / 221 EXT2_BLOCK_SIZE(super)); 222 223 /* 224 * adjust inode count to reflect the adjusted inodes_per_group 225 */ 226 super->s_inodes_count = super->s_inodes_per_group * 227 fs->group_desc_count; 228 super->s_free_inodes_count = super->s_inodes_count; 229 230 /* 231 * Overhead is the number of bookkeeping blocks per group. It 232 * includes the superblock backup, the group descriptor 233 * backups, the inode bitmap, the block bitmap, and the inode 234 * table. 235 * 236 * XXX Not all block groups need the descriptor blocks, but 237 * being clever is tricky... 238 */ 239 overhead = (int) (3 + fs->desc_blocks + fs->inode_blocks_per_group); 240 241 /* 242 * See if the last group is big enough to support the 243 * necessary data structures. If not, we need to get rid of 244 * it. 245 */ 246 rem = (int) ((super->s_blocks_count - super->s_first_data_block) % 247 super->s_blocks_per_group); 248 if ((fs->group_desc_count == 1) && rem && (rem < overhead)) 249 return EXT2_ET_TOOSMALL; 250 if (rem && (rem < overhead+50)) { 251 super->s_blocks_count -= rem; 252 goto retry; 253 } 254 255 /* 256 * At this point we know how big the filesystem will be. So 257 * we can do any and all allocations that depend on the block 258 * count. 259 */ 260 261 retval = ext2fs_get_mem(strlen(fs->device_name) + 80, 262 (void **) &buf); 263 if (retval) 264 goto cleanup; 265 266 sprintf(buf, "block bitmap for %s", fs->device_name); 267 retval = ext2fs_allocate_block_bitmap(fs, buf, &fs->block_map); 268 if (retval) 269 goto cleanup; 270 271 sprintf(buf, "inode bitmap for %s", fs->device_name); 272 retval = ext2fs_allocate_inode_bitmap(fs, buf, &fs->inode_map); 273 if (retval) 274 goto cleanup; 275 276 ext2fs_free_mem((void **) &buf); 277 278 retval = ext2fs_get_mem((size_t) fs->desc_blocks * fs->blocksize, 279 (void **) &fs->group_desc); 280 if (retval) 281 goto cleanup; 282 283 memset(fs->group_desc, 0, (size_t) fs->desc_blocks * fs->blocksize); 284 285 /* 286 * Reserve the superblock and group descriptors for each 287 * group, and fill in the correct group statistics for group. 288 * Note that although the block bitmap, inode bitmap, and 289 * inode table have not been allocated (and in fact won't be 290 * by this routine), they are accounted for nevertheless. 291 */ 292 group_block = super->s_first_data_block; 293 super->s_free_blocks_count = 0; 294 for (i = 0; i < fs->group_desc_count; i++) { 295 if (i == fs->group_desc_count-1) { 296 numblocks = (fs->super->s_blocks_count - 297 fs->super->s_first_data_block) % 298 fs->super->s_blocks_per_group; 299 if (!numblocks) 300 numblocks = fs->super->s_blocks_per_group; 301 } else 302 numblocks = fs->super->s_blocks_per_group; 303 304 if (ext2fs_bg_has_super(fs, i)) { 305 for (j=0; j < fs->desc_blocks+1; j++) 306 ext2fs_mark_block_bitmap(fs->block_map, 307 group_block + j); 308 numblocks -= 1 + fs->desc_blocks; 309 } 310 311 numblocks -= 2 + fs->inode_blocks_per_group; 312 313 super->s_free_blocks_count += numblocks; 314 fs->group_desc[i].bg_free_blocks_count = numblocks; 315 fs->group_desc[i].bg_free_inodes_count = 316 fs->super->s_inodes_per_group; 317 fs->group_desc[i].bg_used_dirs_count = 0; 318 319 group_block += super->s_blocks_per_group; 320 } 321 322 ext2fs_mark_super_dirty(fs); 323 ext2fs_mark_bb_dirty(fs); 324 ext2fs_mark_ib_dirty(fs); 325 326 io_channel_set_blksize(fs->io, fs->blocksize); 327 328 *ret_fs = fs; 329 return 0; 330cleanup: 331 ext2fs_free(fs); 332 return retval; 333} 334 335 336 337