1 /* 2 * linux/fs/fat/misc.c 3 * 4 * Written 1992,1993 by Werner Almesberger 5 * 22/11/2000 - Fixed fat_date_unix2dos for dates earlier than 01/01/1980 6 * and date_dos2unix for date==0 by Igor Zhbanov(bsg@uniyar.ac.ru) 7 */ 8 9 #include <linux/module.h> 10 #include <linux/fs.h> 11 #include <linux/buffer_head.h> 12 #include "fat.h" 13 14 /* 15 * fat_fs_error reports a file system problem that might indicate fa data 16 * corruption/inconsistency. Depending on 'errors' mount option the 17 * panic() is called, or error message is printed FAT and nothing is done, 18 * or filesystem is remounted read-only (default behavior). 19 * In case the file system is remounted read-only, it can be made writable 20 * again by remounting it. 21 */ 22 void fat_fs_error(struct super_block *s, const char *fmt, ...) 23 { 24 struct fat_mount_options *opts = &MSDOS_SB(s)->options; 25 va_list args; 26 27 printk(KERN_ERR "FAT: Filesystem error (dev %s)\n", s->s_id); 28 29 printk(KERN_ERR " "); 30 va_start(args, fmt); 31 vprintk(fmt, args); 32 va_end(args); 33 printk("\n"); 34 35 if (opts->errors == FAT_ERRORS_PANIC) 36 panic(" FAT fs panic from previous error\n"); 37 else if (opts->errors == FAT_ERRORS_RO && !(s->s_flags & MS_RDONLY)) { 38 s->s_flags |= MS_RDONLY; 39 printk(KERN_ERR " File system has been set read-only\n"); 40 } 41 } 42 EXPORT_SYMBOL_GPL(fat_fs_error); 43 44 /* Flushes the number of free clusters on FAT32 */ 45 /* XXX: Need to write one per FSINFO block. Currently only writes 1 */ 46 void fat_clusters_flush(struct super_block *sb) 47 { 48 struct msdos_sb_info *sbi = MSDOS_SB(sb); 49 struct buffer_head *bh; 50 struct fat_boot_fsinfo *fsinfo; 51 52 if (sbi->fat_bits != 32) 53 return; 54 55 bh = sb_bread(sb, sbi->fsinfo_sector); 56 if (bh == NULL) { 57 printk(KERN_ERR "FAT: bread failed in fat_clusters_flush\n"); 58 return; 59 } 60 61 fsinfo = (struct fat_boot_fsinfo *)bh->b_data; 62 /* Sanity check */ 63 if (!IS_FSINFO(fsinfo)) { 64 printk(KERN_ERR "FAT: Invalid FSINFO signature: " 65 "0x%08x, 0x%08x (sector = %lu)\n", 66 le32_to_cpu(fsinfo->signature1), 67 le32_to_cpu(fsinfo->signature2), 68 sbi->fsinfo_sector); 69 } else { 70 if (sbi->free_clusters != -1) 71 fsinfo->free_clusters = cpu_to_le32(sbi->free_clusters); 72 if (sbi->prev_free != -1) 73 fsinfo->next_cluster = cpu_to_le32(sbi->prev_free); 74 mark_buffer_dirty(bh); 75 } 76 brelse(bh); 77 } 78 79 /* 80 * fat_chain_add() adds a new cluster to the chain of clusters represented 81 * by inode. 82 */ 83 int fat_chain_add(struct inode *inode, int new_dclus, int nr_cluster) 84 { 85 struct super_block *sb = inode->i_sb; 86 struct msdos_sb_info *sbi = MSDOS_SB(sb); 87 int ret, new_fclus, last; 88 89 /* 90 * We must locate the last cluster of the file to add this new 91 * one (new_dclus) to the end of the link list (the FAT). 92 */ 93 last = new_fclus = 0; 94 if (MSDOS_I(inode)->i_start) { 95 int fclus, dclus; 96 97 ret = fat_get_cluster(inode, FAT_ENT_EOF, &fclus, &dclus); 98 if (ret < 0) 99 return ret; 100 new_fclus = fclus + 1; 101 last = dclus; 102 } 103 104 /* add new one to the last of the cluster chain */ 105 if (last) { 106 struct fat_entry fatent; 107 108 fatent_init(&fatent); 109 ret = fat_ent_read(inode, &fatent, last); 110 if (ret >= 0) { 111 int wait = inode_needs_sync(inode); 112 ret = fat_ent_write(inode, &fatent, new_dclus, wait); 113 fatent_brelse(&fatent); 114 } 115 if (ret < 0) 116 return ret; 117 // fat_cache_add(inode, new_fclus, new_dclus); 118 } else { 119 MSDOS_I(inode)->i_start = new_dclus; 120 MSDOS_I(inode)->i_logstart = new_dclus; 121 /* 122 * Since generic_write_sync() synchronizes regular files later, 123 * we sync here only directories. 124 */ 125 if (S_ISDIR(inode->i_mode) && IS_DIRSYNC(inode)) { 126 ret = fat_sync_inode(inode); 127 if (ret) 128 return ret; 129 } else 130 mark_inode_dirty(inode); 131 } 132 if (new_fclus != (inode->i_blocks >> (sbi->cluster_bits - 9))) { 133 fat_fs_error(sb, "clusters badly computed (%d != %llu)", 134 new_fclus, 135 (llu)(inode->i_blocks >> (sbi->cluster_bits - 9))); 136 fat_cache_inval_inode(inode); 137 } 138 inode->i_blocks += nr_cluster << (sbi->cluster_bits - 9); 139 140 return 0; 141 } 142 143 extern struct timezone sys_tz; 144 145 /* 146 * The epoch of FAT timestamp is 1980. 147 * : bits : value 148 * date: 0 - 4: day (1 - 31) 149 * date: 5 - 8: month (1 - 12) 150 * date: 9 - 15: year (0 - 127) from 1980 151 * time: 0 - 4: sec (0 - 29) 2sec counts 152 * time: 5 - 10: min (0 - 59) 153 * time: 11 - 15: hour (0 - 23) 154 */ 155 #define SECS_PER_MIN 60 156 #define SECS_PER_HOUR (60 * 60) 157 #define SECS_PER_DAY (SECS_PER_HOUR * 24) 158 #define UNIX_SECS_1980 315532800L 159 #if BITS_PER_LONG == 64 160 #define UNIX_SECS_2108 4354819200L 161 #endif 162 /* days between 1.1.70 and 1.1.80 (2 leap days) */ 163 #define DAYS_DELTA (365 * 10 + 2) 164 /* 120 (2100 - 1980) isn't leap year */ 165 #define YEAR_2100 120 166 #define IS_LEAP_YEAR(y) (!((y) & 3) && (y) != YEAR_2100) 167 168 /* Linear day numbers of the respective 1sts in non-leap years. */ 169 static time_t days_in_year[] = { 170 /* Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec */ 171 0, 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 0, 0, 0, 172 }; 173 174 /* Convert a FAT time/date pair to a UNIX date (seconds since 1 1 70). */ 175 void fat_time_fat2unix(struct msdos_sb_info *sbi, struct timespec *ts, 176 __le16 __time, __le16 __date, u8 time_cs) 177 { 178 u16 time = le16_to_cpu(__time), date = le16_to_cpu(__date); 179 time_t second, day, leap_day, month, year; 180 181 year = date >> 9; 182 month = max(1, (date >> 5) & 0xf); 183 day = max(1, date & 0x1f) - 1; 184 185 leap_day = (year + 3) / 4; 186 if (year > YEAR_2100) /* 2100 isn't leap year */ 187 leap_day--; 188 if (IS_LEAP_YEAR(year) && month > 2) 189 leap_day++; 190 191 second = (time & 0x1f) << 1; 192 second += ((time >> 5) & 0x3f) * SECS_PER_MIN; 193 second += (time >> 11) * SECS_PER_HOUR; 194 second += (year * 365 + leap_day 195 + days_in_year[month] + day 196 + DAYS_DELTA) * SECS_PER_DAY; 197 198 if (!sbi->options.tz_utc) 199 second += sys_tz.tz_minuteswest * SECS_PER_MIN; 200 201 if (time_cs) { 202 ts->tv_sec = second + (time_cs / 100); 203 ts->tv_nsec = (time_cs % 100) * 10000000; 204 } else { 205 ts->tv_sec = second; 206 ts->tv_nsec = 0; 207 } 208 } 209 210 /* Convert linear UNIX date to a FAT time/date pair. */ 211 void fat_time_unix2fat(struct msdos_sb_info *sbi, struct timespec *ts, 212 __le16 *time, __le16 *date, u8 *time_cs) 213 { 214 time_t second = ts->tv_sec; 215 time_t day, leap_day, month, year; 216 217 if (!sbi->options.tz_utc) 218 second -= sys_tz.tz_minuteswest * SECS_PER_MIN; 219 220 /* Jan 1 GMT 00:00:00 1980. But what about another time zone? */ 221 if (second < UNIX_SECS_1980) { 222 *time = 0; 223 *date = cpu_to_le16((0 << 9) | (1 << 5) | 1); 224 if (time_cs) 225 *time_cs = 0; 226 return; 227 } 228 #if BITS_PER_LONG == 64 229 if (second >= UNIX_SECS_2108) { 230 *time = cpu_to_le16((23 << 11) | (59 << 5) | 29); 231 *date = cpu_to_le16((127 << 9) | (12 << 5) | 31); 232 if (time_cs) 233 *time_cs = 199; 234 return; 235 } 236 #endif 237 238 day = second / SECS_PER_DAY - DAYS_DELTA; 239 year = day / 365; 240 leap_day = (year + 3) / 4; 241 if (year > YEAR_2100) /* 2100 isn't leap year */ 242 leap_day--; 243 if (year * 365 + leap_day > day) 244 year--; 245 leap_day = (year + 3) / 4; 246 if (year > YEAR_2100) /* 2100 isn't leap year */ 247 leap_day--; 248 day -= year * 365 + leap_day; 249 250 if (IS_LEAP_YEAR(year) && day == days_in_year[3]) { 251 month = 2; 252 } else { 253 if (IS_LEAP_YEAR(year) && day > days_in_year[3]) 254 day--; 255 for (month = 1; month < 12; month++) { 256 if (days_in_year[month + 1] > day) 257 break; 258 } 259 } 260 day -= days_in_year[month]; 261 262 *time = cpu_to_le16(((second / SECS_PER_HOUR) % 24) << 11 263 | ((second / SECS_PER_MIN) % 60) << 5 264 | (second % SECS_PER_MIN) >> 1); 265 *date = cpu_to_le16((year << 9) | (month << 5) | (day + 1)); 266 if (time_cs) 267 *time_cs = (ts->tv_sec & 1) * 100 + ts->tv_nsec / 10000000; 268 } 269 EXPORT_SYMBOL_GPL(fat_time_unix2fat); 270 271 int fat_sync_bhs(struct buffer_head **bhs, int nr_bhs) 272 { 273 int i, err = 0; 274 275 ll_rw_block(SWRITE, nr_bhs, bhs); 276 for (i = 0; i < nr_bhs; i++) { 277 wait_on_buffer(bhs[i]); 278 if (buffer_eopnotsupp(bhs[i])) { 279 clear_buffer_eopnotsupp(bhs[i]); 280 err = -EOPNOTSUPP; 281 } else if (!err && !buffer_uptodate(bhs[i])) 282 err = -EIO; 283 } 284 return err; 285 } 286 287