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_panic reports a severe file system problem and sets the file system 16 * read-only. The file system can be made writable again by remounting it. 17 */ 18 void fat_fs_panic(struct super_block *s, const char *fmt, ...) 19 { 20 va_list args; 21 22 printk(KERN_ERR "FAT: Filesystem panic (dev %s)\n", s->s_id); 23 24 printk(KERN_ERR " "); 25 va_start(args, fmt); 26 vprintk(fmt, args); 27 va_end(args); 28 printk("\n"); 29 30 if (!(s->s_flags & MS_RDONLY)) { 31 s->s_flags |= MS_RDONLY; 32 printk(KERN_ERR " File system has been set read-only\n"); 33 } 34 } 35 36 EXPORT_SYMBOL_GPL(fat_fs_panic); 37 38 /* Flushes the number of free clusters on FAT32 */ 39 /* XXX: Need to write one per FSINFO block. Currently only writes 1 */ 40 void fat_clusters_flush(struct super_block *sb) 41 { 42 struct msdos_sb_info *sbi = MSDOS_SB(sb); 43 struct buffer_head *bh; 44 struct fat_boot_fsinfo *fsinfo; 45 46 if (sbi->fat_bits != 32) 47 return; 48 49 bh = sb_bread(sb, sbi->fsinfo_sector); 50 if (bh == NULL) { 51 printk(KERN_ERR "FAT: bread failed in fat_clusters_flush\n"); 52 return; 53 } 54 55 fsinfo = (struct fat_boot_fsinfo *)bh->b_data; 56 /* Sanity check */ 57 if (!IS_FSINFO(fsinfo)) { 58 printk(KERN_ERR "FAT: Invalid FSINFO signature: " 59 "0x%08x, 0x%08x (sector = %lu)\n", 60 le32_to_cpu(fsinfo->signature1), 61 le32_to_cpu(fsinfo->signature2), 62 sbi->fsinfo_sector); 63 } else { 64 if (sbi->free_clusters != -1) 65 fsinfo->free_clusters = cpu_to_le32(sbi->free_clusters); 66 if (sbi->prev_free != -1) 67 fsinfo->next_cluster = cpu_to_le32(sbi->prev_free); 68 mark_buffer_dirty(bh); 69 } 70 brelse(bh); 71 } 72 73 /* 74 * fat_chain_add() adds a new cluster to the chain of clusters represented 75 * by inode. 76 */ 77 int fat_chain_add(struct inode *inode, int new_dclus, int nr_cluster) 78 { 79 struct super_block *sb = inode->i_sb; 80 struct msdos_sb_info *sbi = MSDOS_SB(sb); 81 int ret, new_fclus, last; 82 83 /* 84 * We must locate the last cluster of the file to add this new 85 * one (new_dclus) to the end of the link list (the FAT). 86 */ 87 last = new_fclus = 0; 88 if (MSDOS_I(inode)->i_start) { 89 int fclus, dclus; 90 91 ret = fat_get_cluster(inode, FAT_ENT_EOF, &fclus, &dclus); 92 if (ret < 0) 93 return ret; 94 new_fclus = fclus + 1; 95 last = dclus; 96 } 97 98 /* add new one to the last of the cluster chain */ 99 if (last) { 100 struct fat_entry fatent; 101 102 fatent_init(&fatent); 103 ret = fat_ent_read(inode, &fatent, last); 104 if (ret >= 0) { 105 int wait = inode_needs_sync(inode); 106 ret = fat_ent_write(inode, &fatent, new_dclus, wait); 107 fatent_brelse(&fatent); 108 } 109 if (ret < 0) 110 return ret; 111 // fat_cache_add(inode, new_fclus, new_dclus); 112 } else { 113 MSDOS_I(inode)->i_start = new_dclus; 114 MSDOS_I(inode)->i_logstart = new_dclus; 115 /* 116 * Since generic_osync_inode() synchronize later if 117 * this is not directory, we don't here. 118 */ 119 if (S_ISDIR(inode->i_mode) && IS_DIRSYNC(inode)) { 120 ret = fat_sync_inode(inode); 121 if (ret) 122 return ret; 123 } else 124 mark_inode_dirty(inode); 125 } 126 if (new_fclus != (inode->i_blocks >> (sbi->cluster_bits - 9))) { 127 fat_fs_panic(sb, "clusters badly computed (%d != %llu)", 128 new_fclus, 129 (llu)(inode->i_blocks >> (sbi->cluster_bits - 9))); 130 fat_cache_inval_inode(inode); 131 } 132 inode->i_blocks += nr_cluster << (sbi->cluster_bits - 9); 133 134 return 0; 135 } 136 137 extern struct timezone sys_tz; 138 139 /* 140 * The epoch of FAT timestamp is 1980. 141 * : bits : value 142 * date: 0 - 4: day (1 - 31) 143 * date: 5 - 8: month (1 - 12) 144 * date: 9 - 15: year (0 - 127) from 1980 145 * time: 0 - 4: sec (0 - 29) 2sec counts 146 * time: 5 - 10: min (0 - 59) 147 * time: 11 - 15: hour (0 - 23) 148 */ 149 #define SECS_PER_MIN 60 150 #define SECS_PER_HOUR (60 * 60) 151 #define SECS_PER_DAY (SECS_PER_HOUR * 24) 152 #define UNIX_SECS_1980 315532800L 153 #if BITS_PER_LONG == 64 154 #define UNIX_SECS_2108 4354819200L 155 #endif 156 /* days between 1.1.70 and 1.1.80 (2 leap days) */ 157 #define DAYS_DELTA (365 * 10 + 2) 158 /* 120 (2100 - 1980) isn't leap year */ 159 #define YEAR_2100 120 160 #define IS_LEAP_YEAR(y) (!((y) & 3) && (y) != YEAR_2100) 161 162 /* Linear day numbers of the respective 1sts in non-leap years. */ 163 static time_t days_in_year[] = { 164 /* Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec */ 165 0, 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 0, 0, 0, 166 }; 167 168 /* Convert a FAT time/date pair to a UNIX date (seconds since 1 1 70). */ 169 void fat_time_fat2unix(struct msdos_sb_info *sbi, struct timespec *ts, 170 __le16 __time, __le16 __date, u8 time_cs) 171 { 172 u16 time = le16_to_cpu(__time), date = le16_to_cpu(__date); 173 time_t second, day, leap_day, month, year; 174 175 year = date >> 9; 176 month = max(1, (date >> 5) & 0xf); 177 day = max(1, date & 0x1f) - 1; 178 179 leap_day = (year + 3) / 4; 180 if (year > YEAR_2100) /* 2100 isn't leap year */ 181 leap_day--; 182 if (IS_LEAP_YEAR(year) && month > 2) 183 leap_day++; 184 185 second = (time & 0x1f) << 1; 186 second += ((time >> 5) & 0x3f) * SECS_PER_MIN; 187 second += (time >> 11) * SECS_PER_HOUR; 188 second += (year * 365 + leap_day 189 + days_in_year[month] + day 190 + DAYS_DELTA) * SECS_PER_DAY; 191 192 if (!sbi->options.tz_utc) 193 second += sys_tz.tz_minuteswest * SECS_PER_MIN; 194 195 if (time_cs) { 196 ts->tv_sec = second + (time_cs / 100); 197 ts->tv_nsec = (time_cs % 100) * 10000000; 198 } else { 199 ts->tv_sec = second; 200 ts->tv_nsec = 0; 201 } 202 } 203 204 /* Convert linear UNIX date to a FAT time/date pair. */ 205 void fat_time_unix2fat(struct msdos_sb_info *sbi, struct timespec *ts, 206 __le16 *time, __le16 *date, u8 *time_cs) 207 { 208 time_t second = ts->tv_sec; 209 time_t day, leap_day, month, year; 210 211 if (!sbi->options.tz_utc) 212 second -= sys_tz.tz_minuteswest * SECS_PER_MIN; 213 214 /* Jan 1 GMT 00:00:00 1980. But what about another time zone? */ 215 if (second < UNIX_SECS_1980) { 216 *time = 0; 217 *date = cpu_to_le16((0 << 9) | (1 << 5) | 1); 218 if (time_cs) 219 *time_cs = 0; 220 return; 221 } 222 #if BITS_PER_LONG == 64 223 if (second >= UNIX_SECS_2108) { 224 *time = cpu_to_le16((23 << 11) | (59 << 5) | 29); 225 *date = cpu_to_le16((127 << 9) | (12 << 5) | 31); 226 if (time_cs) 227 *time_cs = 199; 228 return; 229 } 230 #endif 231 232 day = second / SECS_PER_DAY - DAYS_DELTA; 233 year = day / 365; 234 leap_day = (year + 3) / 4; 235 if (year > YEAR_2100) /* 2100 isn't leap year */ 236 leap_day--; 237 if (year * 365 + leap_day > day) 238 year--; 239 leap_day = (year + 3) / 4; 240 if (year > YEAR_2100) /* 2100 isn't leap year */ 241 leap_day--; 242 day -= year * 365 + leap_day; 243 244 if (IS_LEAP_YEAR(year) && day == days_in_year[3]) { 245 month = 2; 246 } else { 247 if (IS_LEAP_YEAR(year) && day > days_in_year[3]) 248 day--; 249 for (month = 1; month < 12; month++) { 250 if (days_in_year[month + 1] > day) 251 break; 252 } 253 } 254 day -= days_in_year[month]; 255 256 *time = cpu_to_le16(((second / SECS_PER_HOUR) % 24) << 11 257 | ((second / SECS_PER_MIN) % 60) << 5 258 | (second % SECS_PER_MIN) >> 1); 259 *date = cpu_to_le16((year << 9) | (month << 5) | (day + 1)); 260 if (time_cs) 261 *time_cs = (ts->tv_sec & 1) * 100 + ts->tv_nsec / 10000000; 262 } 263 EXPORT_SYMBOL_GPL(fat_time_unix2fat); 264 265 int fat_sync_bhs(struct buffer_head **bhs, int nr_bhs) 266 { 267 int i, err = 0; 268 269 ll_rw_block(SWRITE, nr_bhs, bhs); 270 for (i = 0; i < nr_bhs; i++) { 271 wait_on_buffer(bhs[i]); 272 if (buffer_eopnotsupp(bhs[i])) { 273 clear_buffer_eopnotsupp(bhs[i]); 274 err = -EOPNOTSUPP; 275 } else if (!err && !buffer_uptodate(bhs[i])) 276 err = -EIO; 277 } 278 return err; 279 } 280 281