initialize.c revision ef344e13d2125e9dae3764b98f9fe3a170cd79e2
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 61errcode_t ext2fs_initialize(const char *name, int flags, 62 struct ext2_super_block *param, 63 io_manager manager, ext2_filsys *ret_fs) 64{ 65 ext2_filsys fs; 66 errcode_t retval; 67 struct ext2_super_block *super; 68 int frags_per_block; 69 int rem; 70 int overhead = 0; 71 blk_t group_block; 72 int ipg; 73 int i, j; 74 blk_t numblocks; 75 char *buf; 76 77 if (!param || !param->s_blocks_count) 78 return EXT2_ET_INVALID_ARGUMENT; 79 80 retval = ext2fs_get_mem(sizeof(struct struct_ext2_filsys), &fs); 81 if (retval) 82 return retval; 83 84 memset(fs, 0, sizeof(struct struct_ext2_filsys)); 85 fs->magic = EXT2_ET_MAGIC_EXT2FS_FILSYS; 86 fs->flags = flags | EXT2_FLAG_RW; 87 fs->umask = 022; 88#ifdef WORDS_BIGENDIAN 89 fs->flags |= EXT2_FLAG_SWAP_BYTES; 90#endif 91 retval = manager->open(name, IO_FLAG_RW, &fs->io); 92 if (retval) 93 goto cleanup; 94 fs->io->app_data = fs; 95 retval = ext2fs_get_mem(strlen(name)+1, &fs->device_name); 96 if (retval) 97 goto cleanup; 98 99 strcpy(fs->device_name, name); 100 retval = ext2fs_get_mem(SUPERBLOCK_SIZE, &super); 101 if (retval) 102 goto cleanup; 103 fs->super = super; 104 105 memset(super, 0, SUPERBLOCK_SIZE); 106 107#define set_field(field, default) (super->field = param->field ? \ 108 param->field : (default)) 109 110 super->s_magic = EXT2_SUPER_MAGIC; 111 super->s_state = EXT2_VALID_FS; 112 113 set_field(s_log_block_size, 0); /* default blocksize: 1024 bytes */ 114 set_field(s_log_frag_size, 0); /* default fragsize: 1024 bytes */ 115 set_field(s_first_data_block, super->s_log_block_size ? 0 : 1); 116 set_field(s_max_mnt_count, EXT2_DFL_MAX_MNT_COUNT); 117 set_field(s_errors, EXT2_ERRORS_DEFAULT); 118 set_field(s_feature_compat, 0); 119 set_field(s_feature_incompat, 0); 120 set_field(s_feature_ro_compat, 0); 121 set_field(s_first_meta_bg, 0); 122 if (super->s_feature_incompat & ~EXT2_LIB_FEATURE_INCOMPAT_SUPP) 123 return EXT2_ET_UNSUPP_FEATURE; 124 if (super->s_feature_ro_compat & ~EXT2_LIB_FEATURE_RO_COMPAT_SUPP) 125 return EXT2_ET_RO_UNSUPP_FEATURE; 126 127 set_field(s_rev_level, EXT2_GOOD_OLD_REV); 128 if (super->s_rev_level >= EXT2_DYNAMIC_REV) { 129 set_field(s_first_ino, EXT2_GOOD_OLD_FIRST_INO); 130 set_field(s_inode_size, EXT2_GOOD_OLD_INODE_SIZE); 131 } 132 133 set_field(s_checkinterval, EXT2_DFL_CHECKINTERVAL); 134 super->s_mkfs_time = super->s_lastcheck = time(NULL); 135 136 super->s_creator_os = CREATOR_OS; 137 138 fs->blocksize = EXT2_BLOCK_SIZE(super); 139 fs->fragsize = EXT2_FRAG_SIZE(super); 140 frags_per_block = fs->blocksize / fs->fragsize; 141 142 /* default: (fs->blocksize*8) blocks/group, up to 2^16 (GDT limit) */ 143 set_field(s_blocks_per_group, fs->blocksize * 8); 144 if (super->s_blocks_per_group > EXT2_MAX_BLOCKS_PER_GROUP(super)) 145 super->s_blocks_per_group = EXT2_MAX_BLOCKS_PER_GROUP(super); 146 super->s_frags_per_group = super->s_blocks_per_group * frags_per_block; 147 148 super->s_blocks_count = param->s_blocks_count; 149 super->s_r_blocks_count = param->s_r_blocks_count; 150 if (super->s_r_blocks_count >= param->s_blocks_count) { 151 retval = EXT2_ET_INVALID_ARGUMENT; 152 goto cleanup; 153 } 154 155 /* 156 * If we're creating an external journal device, we don't need 157 * to bother with the rest. 158 */ 159 if (super->s_feature_incompat & 160 EXT3_FEATURE_INCOMPAT_JOURNAL_DEV) { 161 fs->group_desc_count = 0; 162 ext2fs_mark_super_dirty(fs); 163 *ret_fs = fs; 164 return 0; 165 } 166 167retry: 168 fs->group_desc_count = (super->s_blocks_count - 169 super->s_first_data_block + 170 EXT2_BLOCKS_PER_GROUP(super) - 1) 171 / EXT2_BLOCKS_PER_GROUP(super); 172 if (fs->group_desc_count == 0) 173 return EXT2_ET_TOOSMALL; 174 fs->desc_blocks = (fs->group_desc_count + 175 EXT2_DESC_PER_BLOCK(super) - 1) 176 / EXT2_DESC_PER_BLOCK(super); 177 178 i = fs->blocksize >= 4096 ? 1 : 4096 / fs->blocksize; 179 set_field(s_inodes_count, super->s_blocks_count / i); 180 181 /* 182 * Make sure we have at least EXT2_FIRST_INO + 1 inodes, so 183 * that we have enough inodes for the filesystem(!) 184 */ 185 if (super->s_inodes_count < EXT2_FIRST_INODE(super)+1) 186 super->s_inodes_count = EXT2_FIRST_INODE(super)+1; 187 188 /* 189 * There should be at least as many inodes as the user 190 * requested. Figure out how many inodes per group that 191 * should be. But make sure that we don't allocate more than 192 * one bitmap's worth of inodes each group. 193 */ 194 ipg = (super->s_inodes_count + fs->group_desc_count - 1) / 195 fs->group_desc_count; 196 if (ipg > fs->blocksize * 8) { 197 if (super->s_blocks_per_group >= 256) { 198 /* Try again with slightly different parameters */ 199 super->s_blocks_per_group -= 8; 200 super->s_blocks_count = param->s_blocks_count; 201 super->s_frags_per_group = super->s_blocks_per_group * 202 frags_per_block; 203 goto retry; 204 } else 205 return EXT2_ET_TOO_MANY_INODES; 206 } 207 208 if (ipg > EXT2_MAX_INODES_PER_GROUP(super)) 209 ipg = EXT2_MAX_INODES_PER_GROUP(super); 210 211 super->s_inodes_per_group = ipg; 212 if (super->s_inodes_count > ipg * fs->group_desc_count) 213 super->s_inodes_count = ipg * fs->group_desc_count; 214 215 /* 216 * Make sure the number of inodes per group completely fills 217 * the inode table blocks in the descriptor. If not, add some 218 * additional inodes/group. Waste not, want not... 219 */ 220 fs->inode_blocks_per_group = (((super->s_inodes_per_group * 221 EXT2_INODE_SIZE(super)) + 222 EXT2_BLOCK_SIZE(super) - 1) / 223 EXT2_BLOCK_SIZE(super)); 224 super->s_inodes_per_group = ((fs->inode_blocks_per_group * 225 EXT2_BLOCK_SIZE(super)) / 226 EXT2_INODE_SIZE(super)); 227 /* 228 * Finally, make sure the number of inodes per group is a 229 * multiple of 8. This is needed to simplify the bitmap 230 * splicing code. 231 */ 232 super->s_inodes_per_group &= ~7; 233 fs->inode_blocks_per_group = (((super->s_inodes_per_group * 234 EXT2_INODE_SIZE(super)) + 235 EXT2_BLOCK_SIZE(super) - 1) / 236 EXT2_BLOCK_SIZE(super)); 237 238 /* 239 * adjust inode count to reflect the adjusted inodes_per_group 240 */ 241 super->s_inodes_count = super->s_inodes_per_group * 242 fs->group_desc_count; 243 super->s_free_inodes_count = super->s_inodes_count; 244 245 /* 246 * Overhead is the number of bookkeeping blocks per group. It 247 * includes the superblock backup, the group descriptor 248 * backups, the inode bitmap, the block bitmap, and the inode 249 * table. 250 * 251 * XXX Not all block groups need the descriptor blocks, but 252 * being clever is tricky... 253 */ 254 overhead = (int) (3 + fs->desc_blocks + fs->inode_blocks_per_group); 255 256 /* This can only happen if the user requested too many inodes */ 257 if (overhead > super->s_blocks_per_group) 258 return EXT2_ET_TOO_MANY_INODES; 259 260 /* 261 * See if the last group is big enough to support the 262 * necessary data structures. If not, we need to get rid of 263 * it. 264 */ 265 rem = (int) ((super->s_blocks_count - super->s_first_data_block) % 266 super->s_blocks_per_group); 267 if ((fs->group_desc_count == 1) && rem && (rem < overhead)) 268 return EXT2_ET_TOOSMALL; 269 if (rem && (rem < overhead+50)) { 270 super->s_blocks_count -= rem; 271 goto retry; 272 } 273 274 /* 275 * At this point we know how big the filesystem will be. So 276 * we can do any and all allocations that depend on the block 277 * count. 278 */ 279 280 retval = ext2fs_get_mem(strlen(fs->device_name) + 80, &buf); 281 if (retval) 282 goto cleanup; 283 284 sprintf(buf, "block bitmap for %s", fs->device_name); 285 retval = ext2fs_allocate_block_bitmap(fs, buf, &fs->block_map); 286 if (retval) 287 goto cleanup; 288 289 sprintf(buf, "inode bitmap for %s", fs->device_name); 290 retval = ext2fs_allocate_inode_bitmap(fs, buf, &fs->inode_map); 291 if (retval) 292 goto cleanup; 293 294 ext2fs_free_mem(&buf); 295 296 retval = ext2fs_get_mem((size_t) fs->desc_blocks * fs->blocksize, 297 &fs->group_desc); 298 if (retval) 299 goto cleanup; 300 301 memset(fs->group_desc, 0, (size_t) fs->desc_blocks * fs->blocksize); 302 303 /* 304 * Reserve the superblock and group descriptors for each 305 * group, and fill in the correct group statistics for group. 306 * Note that although the block bitmap, inode bitmap, and 307 * inode table have not been allocated (and in fact won't be 308 * by this routine), they are accounted for nevertheless. 309 */ 310 group_block = super->s_first_data_block; 311 super->s_free_blocks_count = 0; 312 for (i = 0; i < fs->group_desc_count; i++) { 313 numblocks = ext2fs_reserve_super_and_bgd(fs, i, fs->block_map); 314 315 super->s_free_blocks_count += numblocks; 316 fs->group_desc[i].bg_free_blocks_count = numblocks; 317 fs->group_desc[i].bg_free_inodes_count = 318 fs->super->s_inodes_per_group; 319 fs->group_desc[i].bg_used_dirs_count = 0; 320 321 group_block += super->s_blocks_per_group; 322 } 323 324 ext2fs_mark_super_dirty(fs); 325 ext2fs_mark_bb_dirty(fs); 326 ext2fs_mark_ib_dirty(fs); 327 328 io_channel_set_blksize(fs->io, fs->blocksize); 329 330 *ret_fs = fs; 331 return 0; 332cleanup: 333 ext2fs_free(fs); 334 return retval; 335} 336