initialize.c revision 1ad54a940c499a66241f624882f1ffa03ce56d90
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 unsigned int rem; 70 unsigned int overhead = 0; 71 blk_t group_block; 72 unsigned int ipg; 73 dgrp_t i; 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->image_io = fs->io; 95 fs->io->app_data = fs; 96 retval = ext2fs_get_mem(strlen(name)+1, &fs->device_name); 97 if (retval) 98 goto cleanup; 99 100 strcpy(fs->device_name, name); 101 retval = ext2fs_get_mem(SUPERBLOCK_SIZE, &super); 102 if (retval) 103 goto cleanup; 104 fs->super = super; 105 106 memset(super, 0, SUPERBLOCK_SIZE); 107 108#define set_field(field, default) (super->field = param->field ? \ 109 param->field : (default)) 110 111 super->s_magic = EXT2_SUPER_MAGIC; 112 super->s_state = EXT2_VALID_FS; 113 114 set_field(s_log_block_size, 0); /* default blocksize: 1024 bytes */ 115 set_field(s_log_frag_size, 0); /* default fragsize: 1024 bytes */ 116 set_field(s_first_data_block, super->s_log_block_size ? 0 : 1); 117 set_field(s_max_mnt_count, EXT2_DFL_MAX_MNT_COUNT); 118 set_field(s_errors, EXT2_ERRORS_DEFAULT); 119 set_field(s_feature_compat, 0); 120 set_field(s_feature_incompat, 0); 121 set_field(s_feature_ro_compat, 0); 122 set_field(s_first_meta_bg, 0); 123 if (super->s_feature_incompat & ~EXT2_LIB_FEATURE_INCOMPAT_SUPP) 124 return EXT2_ET_UNSUPP_FEATURE; 125 if (super->s_feature_ro_compat & ~EXT2_LIB_FEATURE_RO_COMPAT_SUPP) 126 return EXT2_ET_RO_UNSUPP_FEATURE; 127 128 set_field(s_rev_level, EXT2_GOOD_OLD_REV); 129 if (super->s_rev_level >= EXT2_DYNAMIC_REV) { 130 set_field(s_first_ino, EXT2_GOOD_OLD_FIRST_INO); 131 set_field(s_inode_size, EXT2_GOOD_OLD_INODE_SIZE); 132 } 133 134 set_field(s_checkinterval, EXT2_DFL_CHECKINTERVAL); 135 super->s_mkfs_time = super->s_lastcheck = time(NULL); 136 137 super->s_creator_os = CREATOR_OS; 138 139 fs->blocksize = EXT2_BLOCK_SIZE(super); 140 fs->fragsize = EXT2_FRAG_SIZE(super); 141 frags_per_block = fs->blocksize / fs->fragsize; 142 143 /* default: (fs->blocksize*8) blocks/group, up to 2^16 (GDT limit) */ 144 set_field(s_blocks_per_group, fs->blocksize * 8); 145 if (super->s_blocks_per_group > EXT2_MAX_BLOCKS_PER_GROUP(super)) 146 super->s_blocks_per_group = EXT2_MAX_BLOCKS_PER_GROUP(super); 147 super->s_frags_per_group = super->s_blocks_per_group * frags_per_block; 148 149 super->s_blocks_count = param->s_blocks_count; 150 super->s_r_blocks_count = param->s_r_blocks_count; 151 if (super->s_r_blocks_count >= param->s_blocks_count) { 152 retval = EXT2_ET_INVALID_ARGUMENT; 153 goto cleanup; 154 } 155 156 /* 157 * If we're creating an external journal device, we don't need 158 * to bother with the rest. 159 */ 160 if (super->s_feature_incompat & 161 EXT3_FEATURE_INCOMPAT_JOURNAL_DEV) { 162 fs->group_desc_count = 0; 163 ext2fs_mark_super_dirty(fs); 164 *ret_fs = fs; 165 return 0; 166 } 167 168retry: 169 fs->group_desc_count = (super->s_blocks_count - 170 super->s_first_data_block + 171 EXT2_BLOCKS_PER_GROUP(super) - 1) 172 / EXT2_BLOCKS_PER_GROUP(super); 173 if (fs->group_desc_count == 0) 174 return EXT2_ET_TOOSMALL; 175 fs->desc_blocks = (fs->group_desc_count + 176 EXT2_DESC_PER_BLOCK(super) - 1) 177 / EXT2_DESC_PER_BLOCK(super); 178 179 i = fs->blocksize >= 4096 ? 1 : 4096 / fs->blocksize; 180 set_field(s_inodes_count, super->s_blocks_count / i); 181 182 /* 183 * Make sure we have at least EXT2_FIRST_INO + 1 inodes, so 184 * that we have enough inodes for the filesystem(!) 185 */ 186 if (super->s_inodes_count < EXT2_FIRST_INODE(super)+1) 187 super->s_inodes_count = EXT2_FIRST_INODE(super)+1; 188 189 /* 190 * There should be at least as many inodes as the user 191 * requested. Figure out how many inodes per group that 192 * should be. But make sure that we don't allocate more than 193 * one bitmap's worth of inodes each group. 194 */ 195 ipg = (super->s_inodes_count + fs->group_desc_count - 1) / 196 fs->group_desc_count; 197 if (ipg > fs->blocksize * 8) { 198 if (super->s_blocks_per_group >= 256) { 199 /* Try again with slightly different parameters */ 200 super->s_blocks_per_group -= 8; 201 super->s_blocks_count = param->s_blocks_count; 202 super->s_frags_per_group = super->s_blocks_per_group * 203 frags_per_block; 204 goto retry; 205 } else 206 return EXT2_ET_TOO_MANY_INODES; 207 } 208 209 if (ipg > (unsigned) EXT2_MAX_INODES_PER_GROUP(super)) 210 ipg = EXT2_MAX_INODES_PER_GROUP(super); 211 212 super->s_inodes_per_group = ipg; 213 if (super->s_inodes_count > ipg * fs->group_desc_count) 214 super->s_inodes_count = ipg * fs->group_desc_count; 215 216 /* 217 * Make sure the number of inodes per group completely fills 218 * the inode table blocks in the descriptor. If not, add some 219 * additional inodes/group. Waste not, want not... 220 */ 221 fs->inode_blocks_per_group = (((super->s_inodes_per_group * 222 EXT2_INODE_SIZE(super)) + 223 EXT2_BLOCK_SIZE(super) - 1) / 224 EXT2_BLOCK_SIZE(super)); 225 super->s_inodes_per_group = ((fs->inode_blocks_per_group * 226 EXT2_BLOCK_SIZE(super)) / 227 EXT2_INODE_SIZE(super)); 228 /* 229 * Finally, make sure the number of inodes per group is a 230 * multiple of 8. This is needed to simplify the bitmap 231 * splicing code. 232 */ 233 super->s_inodes_per_group &= ~7; 234 fs->inode_blocks_per_group = (((super->s_inodes_per_group * 235 EXT2_INODE_SIZE(super)) + 236 EXT2_BLOCK_SIZE(super) - 1) / 237 EXT2_BLOCK_SIZE(super)); 238 239 /* 240 * adjust inode count to reflect the adjusted inodes_per_group 241 */ 242 super->s_inodes_count = super->s_inodes_per_group * 243 fs->group_desc_count; 244 super->s_free_inodes_count = super->s_inodes_count; 245 246 /* 247 * Overhead is the number of bookkeeping blocks per group. It 248 * includes the superblock backup, the group descriptor 249 * backups, the inode bitmap, the block bitmap, and the inode 250 * table. 251 * 252 * XXX Not all block groups need the descriptor blocks, but 253 * being clever is tricky... 254 */ 255 overhead = (int) (3 + fs->desc_blocks + fs->inode_blocks_per_group); 256 257 /* This can only happen if the user requested too many inodes */ 258 if (overhead > super->s_blocks_per_group) 259 return EXT2_ET_TOO_MANY_INODES; 260 261 /* 262 * See if the last group is big enough to support the 263 * necessary data structures. If not, we need to get rid of 264 * it. 265 */ 266 rem = ((super->s_blocks_count - super->s_first_data_block) % 267 super->s_blocks_per_group); 268 if ((fs->group_desc_count == 1) && rem && (rem < overhead)) 269 return EXT2_ET_TOOSMALL; 270 if (rem && (rem < overhead+50)) { 271 super->s_blocks_count -= rem; 272 goto retry; 273 } 274 275 /* 276 * At this point we know how big the filesystem will be. So 277 * we can do any and all allocations that depend on the block 278 * count. 279 */ 280 281 retval = ext2fs_get_mem(strlen(fs->device_name) + 80, &buf); 282 if (retval) 283 goto cleanup; 284 285 sprintf(buf, "block bitmap for %s", fs->device_name); 286 retval = ext2fs_allocate_block_bitmap(fs, buf, &fs->block_map); 287 if (retval) 288 goto cleanup; 289 290 sprintf(buf, "inode bitmap for %s", fs->device_name); 291 retval = ext2fs_allocate_inode_bitmap(fs, buf, &fs->inode_map); 292 if (retval) 293 goto cleanup; 294 295 ext2fs_free_mem(&buf); 296 297 retval = ext2fs_get_mem((size_t) fs->desc_blocks * fs->blocksize, 298 &fs->group_desc); 299 if (retval) 300 goto cleanup; 301 302 memset(fs->group_desc, 0, (size_t) fs->desc_blocks * fs->blocksize); 303 304 /* 305 * Reserve the superblock and group descriptors for each 306 * group, and fill in the correct group statistics for group. 307 * Note that although the block bitmap, inode bitmap, and 308 * inode table have not been allocated (and in fact won't be 309 * by this routine), they are accounted for nevertheless. 310 */ 311 group_block = super->s_first_data_block; 312 super->s_free_blocks_count = 0; 313 for (i = 0; i < fs->group_desc_count; i++) { 314 numblocks = ext2fs_reserve_super_and_bgd(fs, i, fs->block_map); 315 316 super->s_free_blocks_count += numblocks; 317 fs->group_desc[i].bg_free_blocks_count = numblocks; 318 fs->group_desc[i].bg_free_inodes_count = 319 fs->super->s_inodes_per_group; 320 fs->group_desc[i].bg_used_dirs_count = 0; 321 322 group_block += super->s_blocks_per_group; 323 } 324 325 ext2fs_mark_super_dirty(fs); 326 ext2fs_mark_bb_dirty(fs); 327 ext2fs_mark_ib_dirty(fs); 328 329 io_channel_set_blksize(fs->io, fs->blocksize); 330 331 *ret_fs = fs; 332 return 0; 333cleanup: 334 ext2fs_free(fs); 335 return retval; 336} 337