1/* vi: set sw=4 ts=4: */ 2/* 3 * closefs.c --- close an ext2 filesystem 4 * 5 * Copyright (C) 1993, 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#if HAVE_UNISTD_H 15#include <unistd.h> 16#endif 17#include <time.h> 18#include <string.h> 19 20#include "ext2_fs.h" 21#include "ext2fsP.h" 22 23static int test_root(int a, int b) 24{ 25 if (a == 0) 26 return 1; 27 while (1) { 28 if (a == 1) 29 return 1; 30 if (a % b) 31 return 0; 32 a = a / b; 33 } 34} 35 36int ext2fs_bg_has_super(ext2_filsys fs, int group_block) 37{ 38 if (!(fs->super->s_feature_ro_compat & 39 EXT2_FEATURE_RO_COMPAT_SPARSE_SUPER)) 40 return 1; 41 42 if (test_root(group_block, 3) || (test_root(group_block, 5)) || 43 test_root(group_block, 7)) 44 return 1; 45 46 return 0; 47} 48 49int ext2fs_super_and_bgd_loc(ext2_filsys fs, 50 dgrp_t group, 51 blk_t *ret_super_blk, 52 blk_t *ret_old_desc_blk, 53 blk_t *ret_new_desc_blk, 54 int *ret_meta_bg) 55{ 56 blk_t group_block, super_blk = 0, old_desc_blk = 0, new_desc_blk = 0; 57 unsigned int meta_bg, meta_bg_size; 58 int numblocks, has_super; 59 int old_desc_blocks; 60 61 group_block = fs->super->s_first_data_block + 62 (group * fs->super->s_blocks_per_group); 63 64 if (fs->super->s_feature_incompat & EXT2_FEATURE_INCOMPAT_META_BG) 65 old_desc_blocks = fs->super->s_first_meta_bg; 66 else 67 old_desc_blocks = 68 fs->desc_blocks + fs->super->s_reserved_gdt_blocks; 69 70 if (group == fs->group_desc_count-1) { 71 numblocks = (fs->super->s_blocks_count - 72 fs->super->s_first_data_block) % 73 fs->super->s_blocks_per_group; 74 if (!numblocks) 75 numblocks = fs->super->s_blocks_per_group; 76 } else 77 numblocks = fs->super->s_blocks_per_group; 78 79 has_super = ext2fs_bg_has_super(fs, group); 80 81 if (has_super) { 82 super_blk = group_block; 83 numblocks--; 84 } 85 meta_bg_size = (fs->blocksize / sizeof (struct ext2_group_desc)); 86 meta_bg = group / meta_bg_size; 87 88 if (!(fs->super->s_feature_incompat & EXT2_FEATURE_INCOMPAT_META_BG) || 89 (meta_bg < fs->super->s_first_meta_bg)) { 90 if (has_super) { 91 old_desc_blk = group_block + 1; 92 numblocks -= old_desc_blocks; 93 } 94 } else { 95 if (((group % meta_bg_size) == 0) || 96 ((group % meta_bg_size) == 1) || 97 ((group % meta_bg_size) == (meta_bg_size-1))) { 98 if (has_super) 99 has_super = 1; 100 new_desc_blk = group_block + has_super; 101 numblocks--; 102 } 103 } 104 105 numblocks -= 2 + fs->inode_blocks_per_group; 106 107 if (ret_super_blk) 108 *ret_super_blk = super_blk; 109 if (ret_old_desc_blk) 110 *ret_old_desc_blk = old_desc_blk; 111 if (ret_new_desc_blk) 112 *ret_new_desc_blk = new_desc_blk; 113 if (ret_meta_bg) 114 *ret_meta_bg = meta_bg; 115 return numblocks; 116} 117 118 119/* 120 * This function forces out the primary superblock. We need to only 121 * write out those fields which we have changed, since if the 122 * filesystem is mounted, it may have changed some of the other 123 * fields. 124 * 125 * It takes as input a superblock which has already been byte swapped 126 * (if necessary). 127 * 128 */ 129static errcode_t write_primary_superblock(ext2_filsys fs, 130 struct ext2_super_block *super) 131{ 132 __u16 *old_super, *new_super; 133 int check_idx, write_idx, size; 134 errcode_t retval; 135 136 if (!fs->io->manager->write_byte || !fs->orig_super) { 137 io_channel_set_blksize(fs->io, SUPERBLOCK_OFFSET); 138 retval = io_channel_write_blk(fs->io, 1, -SUPERBLOCK_SIZE, 139 super); 140 io_channel_set_blksize(fs->io, fs->blocksize); 141 return retval; 142 } 143 144 old_super = (__u16 *) fs->orig_super; 145 new_super = (__u16 *) super; 146 147 for (check_idx = 0; check_idx < SUPERBLOCK_SIZE/2; check_idx++) { 148 if (old_super[check_idx] == new_super[check_idx]) 149 continue; 150 write_idx = check_idx; 151 for (check_idx++; check_idx < SUPERBLOCK_SIZE/2; check_idx++) 152 if (old_super[check_idx] == new_super[check_idx]) 153 break; 154 size = 2 * (check_idx - write_idx); 155 retval = io_channel_write_byte(fs->io, 156 SUPERBLOCK_OFFSET + (2 * write_idx), size, 157 new_super + write_idx); 158 if (retval) 159 return retval; 160 } 161 memcpy(fs->orig_super, super, SUPERBLOCK_SIZE); 162 return 0; 163} 164 165 166/* 167 * Updates the revision to EXT2_DYNAMIC_REV 168 */ 169void ext2fs_update_dynamic_rev(ext2_filsys fs) 170{ 171 struct ext2_super_block *sb = fs->super; 172 173 if (sb->s_rev_level > EXT2_GOOD_OLD_REV) 174 return; 175 176 sb->s_rev_level = EXT2_DYNAMIC_REV; 177 sb->s_first_ino = EXT2_GOOD_OLD_FIRST_INO; 178 sb->s_inode_size = EXT2_GOOD_OLD_INODE_SIZE; 179 /* s_uuid is handled by e2fsck already */ 180 /* other fields should be left alone */ 181} 182 183static errcode_t write_backup_super(ext2_filsys fs, dgrp_t group, 184 blk_t group_block, 185 struct ext2_super_block *super_shadow) 186{ 187 dgrp_t sgrp = group; 188 189 if (sgrp > ((1 << 16) - 1)) 190 sgrp = (1 << 16) - 1; 191#if BB_BIG_ENDIAN 192 if (fs->flags & EXT2_FLAG_SWAP_BYTES) 193 super_shadow->s_block_group_nr = ext2fs_swab16(sgrp); 194 else 195#endif 196 fs->super->s_block_group_nr = sgrp; 197 198 return io_channel_write_blk(fs->io, group_block, -SUPERBLOCK_SIZE, 199 super_shadow); 200} 201 202 203errcode_t ext2fs_flush(ext2_filsys fs) 204{ 205 dgrp_t i; 206 blk_t group_block; 207 errcode_t retval; 208 unsigned long fs_state; 209 struct ext2_super_block *super_shadow = 0; 210 struct ext2_group_desc *group_shadow = 0; 211 char *group_ptr; 212 int old_desc_blocks; 213#if BB_BIG_ENDIAN 214 dgrp_t j; 215 struct ext2_group_desc *s, *t; 216#endif 217 218 EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS); 219 220 fs_state = fs->super->s_state; 221 222 fs->super->s_wtime = time(NULL); 223 fs->super->s_block_group_nr = 0; 224#if BB_BIG_ENDIAN 225 if (fs->flags & EXT2_FLAG_SWAP_BYTES) { 226 retval = EXT2_ET_NO_MEMORY; 227 retval = ext2fs_get_mem(SUPERBLOCK_SIZE, &super_shadow); 228 if (retval) 229 goto errout; 230 retval = ext2fs_get_mem((size_t)(fs->blocksize * 231 fs->desc_blocks), 232 &group_shadow); 233 if (retval) 234 goto errout; 235 memset(group_shadow, 0, (size_t) fs->blocksize * 236 fs->desc_blocks); 237 238 /* swap the group descriptors */ 239 for (j=0, s=fs->group_desc, t=group_shadow; 240 j < fs->group_desc_count; j++, t++, s++) { 241 *t = *s; 242 ext2fs_swap_group_desc(t); 243 } 244 } else { 245 super_shadow = fs->super; 246 group_shadow = fs->group_desc; 247 } 248#else 249 super_shadow = fs->super; 250 group_shadow = fs->group_desc; 251#endif 252 253 /* 254 * If this is an external journal device, don't write out the 255 * block group descriptors or any of the backup superblocks 256 */ 257 if (fs->super->s_feature_incompat & 258 EXT3_FEATURE_INCOMPAT_JOURNAL_DEV) 259 goto write_primary_superblock_only; 260 261 /* 262 * Set the state of the FS to be non-valid. (The state has 263 * already been backed up earlier, and will be restored after 264 * we write out the backup superblocks.) 265 */ 266 fs->super->s_state &= ~EXT2_VALID_FS; 267#if BB_BIG_ENDIAN 268 if (fs->flags & EXT2_FLAG_SWAP_BYTES) { 269 *super_shadow = *fs->super; 270 ext2fs_swap_super(super_shadow); 271 } 272#endif 273 274 /* 275 * Write out the master group descriptors, and the backup 276 * superblocks and group descriptors. 277 */ 278 group_block = fs->super->s_first_data_block; 279 group_ptr = (char *) group_shadow; 280 if (fs->super->s_feature_incompat & EXT2_FEATURE_INCOMPAT_META_BG) 281 old_desc_blocks = fs->super->s_first_meta_bg; 282 else 283 old_desc_blocks = fs->desc_blocks; 284 285 for (i = 0; i < fs->group_desc_count; i++) { 286 blk_t super_blk, old_desc_blk, new_desc_blk; 287 int meta_bg; 288 289 ext2fs_super_and_bgd_loc(fs, i, &super_blk, &old_desc_blk, 290 &new_desc_blk, &meta_bg); 291 292 if (!(fs->flags & EXT2_FLAG_MASTER_SB_ONLY) &&i && super_blk) { 293 retval = write_backup_super(fs, i, super_blk, 294 super_shadow); 295 if (retval) 296 goto errout; 297 } 298 if (fs->flags & EXT2_FLAG_SUPER_ONLY) 299 continue; 300 if ((old_desc_blk) && 301 (!(fs->flags & EXT2_FLAG_MASTER_SB_ONLY) || (i == 0))) { 302 retval = io_channel_write_blk(fs->io, 303 old_desc_blk, old_desc_blocks, group_ptr); 304 if (retval) 305 goto errout; 306 } 307 if (new_desc_blk) { 308 retval = io_channel_write_blk(fs->io, new_desc_blk, 309 1, group_ptr + (meta_bg*fs->blocksize)); 310 if (retval) 311 goto errout; 312 } 313 } 314 fs->super->s_block_group_nr = 0; 315 fs->super->s_state = fs_state; 316#if BB_BIG_ENDIAN 317 if (fs->flags & EXT2_FLAG_SWAP_BYTES) { 318 *super_shadow = *fs->super; 319 ext2fs_swap_super(super_shadow); 320 } 321#endif 322 323 /* 324 * If the write_bitmaps() function is present, call it to 325 * flush the bitmaps. This is done this way so that a simple 326 * program that doesn't mess with the bitmaps doesn't need to 327 * drag in the bitmaps.c code. 328 */ 329 if (fs->write_bitmaps) { 330 retval = fs->write_bitmaps(fs); 331 if (retval) 332 goto errout; 333 } 334 335write_primary_superblock_only: 336 /* 337 * Write out master superblock. This has to be done 338 * separately, since it is located at a fixed location 339 * (SUPERBLOCK_OFFSET). We flush all other pending changes 340 * out to disk first, just to avoid a race condition with an 341 * insy-tinsy window.... 342 */ 343 retval = io_channel_flush(fs->io); 344 retval = write_primary_superblock(fs, super_shadow); 345 if (retval) 346 goto errout; 347 348 fs->flags &= ~EXT2_FLAG_DIRTY; 349 350 retval = io_channel_flush(fs->io); 351errout: 352 fs->super->s_state = fs_state; 353 if (fs->flags & EXT2_FLAG_SWAP_BYTES) { 354 if (super_shadow) 355 ext2fs_free_mem(&super_shadow); 356 if (group_shadow) 357 ext2fs_free_mem(&group_shadow); 358 } 359 return retval; 360} 361 362errcode_t ext2fs_close(ext2_filsys fs) 363{ 364 errcode_t retval; 365 366 EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS); 367 368 if (fs->flags & EXT2_FLAG_DIRTY) { 369 retval = ext2fs_flush(fs); 370 if (retval) 371 return retval; 372 } 373 if (fs->write_bitmaps) { 374 retval = fs->write_bitmaps(fs); 375 if (retval) 376 return retval; 377 } 378 ext2fs_free(fs); 379 return 0; 380} 381