closefs.c revision 3c6b8977d44c66f0a50dd77c18a78b57b1022f8c
1/* 2 * closefs.c --- close an ext2 filesystem 3 * 4 * Copyright (C) 1993, 1994, 1995, 1996 Theodore Ts'o. 5 * 6 * %Begin-Header% 7 * This file may be redistributed under the terms of the GNU Public 8 * License. 9 * %End-Header% 10 */ 11 12#include <stdio.h> 13#if HAVE_UNISTD_H 14#include <unistd.h> 15#endif 16#include <time.h> 17#include <string.h> 18 19#include "ext2_fs.h" 20#include "ext2fsP.h" 21 22static int test_root(int a, int b) 23{ 24 if (a == 0) 25 return 1; 26 while (1) { 27 if (a == 1) 28 return 1; 29 if (a % b) 30 return 0; 31 a = a / b; 32 } 33} 34 35int ext2fs_bg_has_super(ext2_filsys fs, int group_block) 36{ 37 if (!(fs->super->s_feature_ro_compat & 38 EXT2_FEATURE_RO_COMPAT_SPARSE_SUPER)) 39 return 1; 40 41 if (test_root(group_block, 3) || (test_root(group_block, 5)) || 42 test_root(group_block, 7)) 43 return 1; 44 45 return 0; 46} 47 48/* 49 * This function forces out the primary superblock. We need to only 50 * write out those fields which we have changed, since if the 51 * filesystem is mounted, it may have changed some of the other 52 * fields. 53 * 54 * It takes as input a superblock which has already been byte swapped 55 * (if necessary). 56 * 57 */ 58static errcode_t write_primary_superblock(ext2_filsys fs, 59 struct ext2_super_block *super) 60{ 61 __u16 *old_super, *new_super; 62 int check_idx, write_idx, size; 63 errcode_t retval; 64 65 if (!fs->io->manager->write_byte || !fs->orig_super) { 66 io_channel_set_blksize(fs->io, SUPERBLOCK_OFFSET); 67 retval = io_channel_write_blk(fs->io, 1, -SUPERBLOCK_SIZE, 68 super); 69 io_channel_set_blksize(fs->io, fs->blocksize); 70 return retval; 71 } 72 73 old_super = (__u16 *) fs->orig_super; 74 new_super = (__u16 *) super; 75 76 for (check_idx = 0; check_idx < SUPERBLOCK_SIZE/2; check_idx++) { 77 if (old_super[check_idx] == new_super[check_idx]) 78 continue; 79 write_idx = check_idx; 80 for (check_idx++; check_idx < SUPERBLOCK_SIZE/2; check_idx++) 81 if (old_super[check_idx] == new_super[check_idx]) 82 break; 83 size = 2 * (check_idx - write_idx); 84#if 0 85 printf("Writing %d bytes starting at %d\n", 86 size, write_idx*2); 87#endif 88 retval = io_channel_write_byte(fs->io, 89 SUPERBLOCK_OFFSET + (2 * write_idx), size, 90 new_super + write_idx); 91 if (retval) 92 return retval; 93 } 94 memcpy(fs->orig_super, super, SUPERBLOCK_SIZE); 95 return 0; 96} 97 98 99/* 100 * Updates the revision to EXT2_DYNAMIC_REV 101 */ 102void ext2fs_update_dynamic_rev(ext2_filsys fs) 103{ 104 struct ext2_super_block *sb = fs->super; 105 106 if (sb->s_rev_level > EXT2_GOOD_OLD_REV) 107 return; 108 109 sb->s_rev_level = EXT2_DYNAMIC_REV; 110 sb->s_first_ino = EXT2_GOOD_OLD_FIRST_INO; 111 sb->s_inode_size = EXT2_GOOD_OLD_INODE_SIZE; 112 /* s_uuid is handled by e2fsck already */ 113 /* other fields should be left alone */ 114} 115 116errcode_t ext2fs_flush(ext2_filsys fs) 117{ 118 dgrp_t i,j,maxgroup,sgrp; 119 blk_t group_block; 120 errcode_t retval; 121 char *group_ptr; 122 unsigned long fs_state; 123 struct ext2_super_block *super_shadow = 0; 124 struct ext2_group_desc *group_shadow = 0; 125 struct ext2_group_desc *s, *t; 126 127 EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS); 128 129 fs_state = fs->super->s_state; 130 131 fs->super->s_wtime = time(NULL); 132 fs->super->s_block_group_nr = 0; 133#ifdef EXT2FS_ENABLE_SWAPFS 134 if (fs->flags & EXT2_FLAG_SWAP_BYTES) { 135 retval = EXT2_ET_NO_MEMORY; 136 retval = ext2fs_get_mem(SUPERBLOCK_SIZE, 137 (void **) &super_shadow); 138 if (retval) 139 goto errout; 140 retval = ext2fs_get_mem((size_t)(fs->blocksize * 141 fs->desc_blocks), 142 (void **) &group_shadow); 143 if (retval) 144 goto errout; 145 memset(group_shadow, 0, (size_t) fs->blocksize * 146 fs->desc_blocks); 147 148 /* swap the superblock */ 149 *super_shadow = *fs->super; 150 ext2fs_swap_super(super_shadow); 151 152 /* swap the group descriptors */ 153 for (j=0, s=fs->group_desc, t=group_shadow; 154 j < fs->group_desc_count; j++, t++, s++) { 155 *t = *s; 156 ext2fs_swap_group_desc(t); 157 } 158 } else { 159 super_shadow = fs->super; 160 group_shadow = fs->group_desc; 161 } 162#else 163 super_shadow = fs->super; 164 group_shadow = fs->group_desc; 165#endif 166 167 /* 168 * Write out master superblock. This has to be done 169 * separately, since it is located at a fixed location 170 * (SUPERBLOCK_OFFSET). 171 */ 172 retval = write_primary_superblock(fs, super_shadow); 173 if (retval) 174 goto errout; 175 176 /* 177 * If this is an external journal device, don't write out the 178 * block group descriptors or any of the backup superblocks 179 */ 180 if (fs->super->s_feature_incompat & 181 EXT3_FEATURE_INCOMPAT_JOURNAL_DEV) { 182 retval = 0; 183 goto errout; 184 } 185 186 /* 187 * Set the state of the FS to be non-valid. (The state has 188 * already been backed up earlier, and will be restored when 189 * we exit.) 190 */ 191 fs->super->s_state &= ~EXT2_VALID_FS; 192#ifdef EXT2FS_ENABLE_SWAPFS 193 if (fs->flags & EXT2_FLAG_SWAP_BYTES) { 194 *super_shadow = *fs->super; 195 ext2fs_swap_super(super_shadow); 196 } 197#endif 198 199 /* 200 * Write out the master group descriptors, and the backup 201 * superblocks and group descriptors. 202 */ 203 group_block = fs->super->s_first_data_block; 204 maxgroup = (fs->flags & EXT2_FLAG_MASTER_SB_ONLY) ? 1 : 205 fs->group_desc_count; 206 for (i = 0; i < maxgroup; i++) { 207 if (!ext2fs_bg_has_super(fs, i)) 208 goto next_group; 209 210 sgrp = i; 211 if (sgrp > ((1 << 16) - 1)) 212 sgrp = (1 << 16) - 1; 213#ifdef EXT2FS_ENABLE_SWAPFS 214 if (fs->flags & EXT2_FLAG_SWAP_BYTES) 215 super_shadow->s_block_group_nr = ext2fs_swab16(sgrp); 216 else 217#endif 218 fs->super->s_block_group_nr = sgrp; 219 220 if (i !=0 ) { 221 retval = io_channel_write_blk(fs->io, group_block, 222 -SUPERBLOCK_SIZE, 223 super_shadow); 224 if (retval) 225 goto errout; 226 } 227 if (fs->flags & EXT2_FLAG_SUPER_ONLY) 228 goto next_group; 229 group_ptr = (char *) group_shadow; 230 for (j=0; j < fs->desc_blocks; j++) { 231 retval = io_channel_write_blk(fs->io, 232 group_block+1+j, 1, 233 group_ptr); 234 if (retval) 235 goto errout; 236 group_ptr += fs->blocksize; 237 } 238 next_group: 239 group_block += EXT2_BLOCKS_PER_GROUP(fs->super); 240 } 241 fs->super->s_block_group_nr = 0; 242 243 /* 244 * If the write_bitmaps() function is present, call it to 245 * flush the bitmaps. This is done this way so that a simple 246 * program that doesn't mess with the bitmaps doesn't need to 247 * drag in the bitmaps.c code. 248 */ 249 if (fs->write_bitmaps) { 250 retval = fs->write_bitmaps(fs); 251 if (retval) 252 goto errout; 253 } 254 255 fs->flags &= ~EXT2_FLAG_DIRTY; 256 257 /* 258 * Flush the blocks out to disk 259 */ 260 retval = io_channel_flush(fs->io); 261errout: 262 fs->super->s_state = fs_state; 263 if (fs->flags & EXT2_FLAG_SWAP_BYTES) { 264 if (super_shadow) 265 ext2fs_free_mem((void **) &super_shadow); 266 if (group_shadow) 267 ext2fs_free_mem((void **) &group_shadow); 268 } 269 return retval; 270} 271 272errcode_t ext2fs_close(ext2_filsys fs) 273{ 274 errcode_t retval; 275 276 EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS); 277 278 if (fs->flags & EXT2_FLAG_DIRTY) { 279 retval = ext2fs_flush(fs); 280 if (retval) 281 return retval; 282 } 283 if (fs->write_bitmaps) { 284 retval = fs->write_bitmaps(fs); 285 if (retval) 286 return retval; 287 } 288 ext2fs_free(fs); 289 return 0; 290} 291 292