initialize.c revision 932a489cdf6bc83d69e59d3f8e0a57b733799ce1
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 i, j; 67 blk_t numblocks; 68 char *buf; 69 70 if (!param || !param->s_blocks_count) 71 return EXT2_ET_INVALID_ARGUMENT; 72 73 retval = ext2fs_get_mem(sizeof(struct struct_ext2_filsys), 74 (void **) &fs); 75 if (retval) 76 return retval; 77 78 memset(fs, 0, sizeof(struct struct_ext2_filsys)); 79 fs->magic = EXT2_ET_MAGIC_EXT2FS_FILSYS; 80 fs->flags = flags | EXT2_FLAG_RW; 81 fs->umask = 022; 82#ifdef WORDS_BIGENDIAN 83 fs->flags |= EXT2_FLAG_SWAP_BYTES; 84#endif 85 retval = manager->open(name, IO_FLAG_RW, &fs->io); 86 if (retval) 87 goto cleanup; 88 fs->io->app_data = fs; 89 retval = ext2fs_get_mem(strlen(name)+1, (void **) &fs->device_name); 90 if (retval) 91 goto cleanup; 92 93 strcpy(fs->device_name, name); 94 retval = ext2fs_get_mem(SUPERBLOCK_SIZE, (void **) &super); 95 if (retval) 96 goto cleanup; 97 fs->super = super; 98 99 memset(super, 0, SUPERBLOCK_SIZE); 100 101#define set_field(field, default) (super->field = param->field ? \ 102 param->field : (default)) 103 104 super->s_magic = EXT2_SUPER_MAGIC; 105 super->s_state = EXT2_VALID_FS; 106 107 set_field(s_log_block_size, 0); /* default blocksize: 1024 bytes */ 108 set_field(s_log_frag_size, 0); /* default fragsize: 1024 bytes */ 109 set_field(s_first_data_block, super->s_log_block_size ? 0 : 1); 110 set_field(s_max_mnt_count, EXT2_DFL_MAX_MNT_COUNT); 111 set_field(s_errors, EXT2_ERRORS_DEFAULT); 112 set_field(s_feature_compat, 0); 113 set_field(s_feature_incompat, 0); 114 set_field(s_feature_ro_compat, 0); 115 if (super->s_feature_incompat & ~EXT2_LIB_FEATURE_INCOMPAT_SUPP) 116 return EXT2_ET_UNSUPP_FEATURE; 117 if (super->s_feature_ro_compat & ~EXT2_LIB_FEATURE_RO_COMPAT_SUPP) 118 return EXT2_ET_RO_UNSUPP_FEATURE; 119 120 set_field(s_rev_level, EXT2_GOOD_OLD_REV); 121 if (super->s_rev_level >= EXT2_DYNAMIC_REV) { 122 set_field(s_first_ino, EXT2_GOOD_OLD_FIRST_INO); 123 set_field(s_inode_size, EXT2_GOOD_OLD_INODE_SIZE); 124 } 125 126 set_field(s_checkinterval, EXT2_DFL_CHECKINTERVAL); 127 super->s_lastcheck = time(NULL); 128 129 super->s_creator_os = CREATOR_OS; 130 131 fs->blocksize = EXT2_BLOCK_SIZE(super); 132 fs->fragsize = EXT2_FRAG_SIZE(super); 133 frags_per_block = fs->blocksize / fs->fragsize; 134 135 /* default: (fs->blocksize*8) blocks/group */ 136 set_field(s_blocks_per_group, fs->blocksize*8); 137 super->s_frags_per_group = super->s_blocks_per_group * frags_per_block; 138 139 super->s_blocks_count = param->s_blocks_count; 140 super->s_r_blocks_count = param->s_r_blocks_count; 141 if (super->s_r_blocks_count >= param->s_blocks_count) { 142 retval = EXT2_ET_INVALID_ARGUMENT; 143 goto cleanup; 144 } 145 146 /* 147 * If we're creating an external journal device, we don't need 148 * to bother with the rest. 149 */ 150 if (super->s_feature_incompat & 151 EXT3_FEATURE_INCOMPAT_JOURNAL_DEV) { 152 fs->group_desc_count = 0; 153 ext2fs_mark_super_dirty(fs); 154 *ret_fs = fs; 155 return 0; 156 } 157 158retry: 159 fs->group_desc_count = (super->s_blocks_count - 160 super->s_first_data_block + 161 EXT2_BLOCKS_PER_GROUP(super) - 1) 162 / EXT2_BLOCKS_PER_GROUP(super); 163 if (fs->group_desc_count == 0) 164 return EXT2_ET_TOOSMALL; 165 fs->desc_blocks = (fs->group_desc_count + 166 EXT2_DESC_PER_BLOCK(super) - 1) 167 / EXT2_DESC_PER_BLOCK(super); 168 169 i = fs->blocksize >= 4096 ? 1 : 4096 / fs->blocksize; 170 set_field(s_inodes_count, super->s_blocks_count / i); 171 172 /* 173 * Make sure we have at least EXT2_FIRST_INO + 1 inodes, so 174 * that we have enough inodes for the filesystem(!) 175 */ 176 if (super->s_inodes_count < EXT2_FIRST_INODE(super)+1) 177 super->s_inodes_count = EXT2_FIRST_INODE(super)+1; 178 179 /* 180 * There should be at least as many inodes as the user 181 * requested. Figure out how many inodes per group that 182 * should be. But make sure that we don't allocate more than 183 * one bitmap's worth of inodes 184 */ 185 super->s_inodes_per_group = (super->s_inodes_count + 186 fs->group_desc_count - 1) / 187 fs->group_desc_count; 188 if (super->s_inodes_per_group > fs->blocksize*8) 189 super->s_inodes_per_group = fs->blocksize*8; 190 191 /* 192 * Make sure the number of inodes per group completely fills 193 * the inode table blocks in the descriptor. If not, add some 194 * additional inodes/group. Waste not, want not... 195 */ 196 fs->inode_blocks_per_group = (((super->s_inodes_per_group * 197 EXT2_INODE_SIZE(super)) + 198 EXT2_BLOCK_SIZE(super) - 1) / 199 EXT2_BLOCK_SIZE(super)); 200 super->s_inodes_per_group = ((fs->inode_blocks_per_group * 201 EXT2_BLOCK_SIZE(super)) / 202 EXT2_INODE_SIZE(super)); 203 /* 204 * Finally, make sure the number of inodes per group is a 205 * multiple of 8. This is needed to simplify the bitmap 206 * splicing code. 207 */ 208 super->s_inodes_per_group &= ~7; 209 fs->inode_blocks_per_group = (((super->s_inodes_per_group * 210 EXT2_INODE_SIZE(super)) + 211 EXT2_BLOCK_SIZE(super) - 1) / 212 EXT2_BLOCK_SIZE(super)); 213 214 /* 215 * adjust inode count to reflect the adjusted inodes_per_group 216 */ 217 super->s_inodes_count = super->s_inodes_per_group * 218 fs->group_desc_count; 219 super->s_free_inodes_count = super->s_inodes_count; 220 221 /* 222 * Overhead is the number of bookkeeping blocks per group. It 223 * includes the superblock backup, the group descriptor 224 * backups, the inode bitmap, the block bitmap, and the inode 225 * table. 226 * 227 * XXX Not all block groups need the descriptor blocks, but 228 * being clever is tricky... 229 */ 230 overhead = (int) (3 + fs->desc_blocks + fs->inode_blocks_per_group); 231 232 /* 233 * See if the last group is big enough to support the 234 * necessary data structures. If not, we need to get rid of 235 * it. 236 */ 237 rem = (int) ((super->s_blocks_count - super->s_first_data_block) % 238 super->s_blocks_per_group); 239 if ((fs->group_desc_count == 1) && rem && (rem < overhead)) 240 return EXT2_ET_TOOSMALL; 241 if (rem && (rem < overhead+50)) { 242 super->s_blocks_count -= rem; 243 goto retry; 244 } 245 246 /* 247 * At this point we know how big the filesystem will be. So 248 * we can do any and all allocations that depend on the block 249 * count. 250 */ 251 252 retval = ext2fs_get_mem(strlen(fs->device_name) + 80, 253 (void **) &buf); 254 if (retval) 255 goto cleanup; 256 257 sprintf(buf, "block bitmap for %s", fs->device_name); 258 retval = ext2fs_allocate_block_bitmap(fs, buf, &fs->block_map); 259 if (retval) 260 goto cleanup; 261 262 sprintf(buf, "inode bitmap for %s", fs->device_name); 263 retval = ext2fs_allocate_inode_bitmap(fs, buf, &fs->inode_map); 264 if (retval) 265 goto cleanup; 266 267 ext2fs_free_mem((void **) &buf); 268 269 retval = ext2fs_get_mem((size_t) fs->desc_blocks * fs->blocksize, 270 (void **) &fs->group_desc); 271 if (retval) 272 goto cleanup; 273 274 memset(fs->group_desc, 0, (size_t) fs->desc_blocks * fs->blocksize); 275 276 /* 277 * Reserve the superblock and group descriptors for each 278 * group, and fill in the correct group statistics for group. 279 * Note that although the block bitmap, inode bitmap, and 280 * inode table have not been allocated (and in fact won't be 281 * by this routine), they are accounted for nevertheless. 282 */ 283 group_block = super->s_first_data_block; 284 super->s_free_blocks_count = 0; 285 for (i = 0; i < fs->group_desc_count; i++) { 286 if (i == fs->group_desc_count-1) { 287 numblocks = (fs->super->s_blocks_count - 288 fs->super->s_first_data_block) % 289 fs->super->s_blocks_per_group; 290 if (!numblocks) 291 numblocks = fs->super->s_blocks_per_group; 292 } else 293 numblocks = fs->super->s_blocks_per_group; 294 295 if (ext2fs_bg_has_super(fs, i)) { 296 for (j=0; j < fs->desc_blocks+1; j++) 297 ext2fs_mark_block_bitmap(fs->block_map, 298 group_block + j); 299 numblocks -= 1 + fs->desc_blocks; 300 } 301 302 numblocks -= 2 + fs->inode_blocks_per_group; 303 304 super->s_free_blocks_count += numblocks; 305 fs->group_desc[i].bg_free_blocks_count = numblocks; 306 fs->group_desc[i].bg_free_inodes_count = 307 fs->super->s_inodes_per_group; 308 fs->group_desc[i].bg_used_dirs_count = 0; 309 310 group_block += super->s_blocks_per_group; 311 } 312 313 ext2fs_mark_super_dirty(fs); 314 ext2fs_mark_bb_dirty(fs); 315 ext2fs_mark_ib_dirty(fs); 316 317 io_channel_set_blksize(fs->io, fs->blocksize); 318 319 *ret_fs = fs; 320 return 0; 321cleanup: 322 ext2fs_free(fs); 323 return retval; 324} 325 326 327 328