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 <linux/time.h> 13 #include "fat.h" 14 15 /* 16 * fat_fs_error reports a file system problem that might indicate fa data 17 * corruption/inconsistency. Depending on 'errors' mount option the 18 * panic() is called, or error message is printed FAT and nothing is done, 19 * or filesystem is remounted read-only (default behavior). 20 * In case the file system is remounted read-only, it can be made writable 21 * again by remounting it. 22 */ 23 void fat_fs_error(struct super_block *s, const char *fmt, ...) 24 { 25 struct fat_mount_options *opts = &MSDOS_SB(s)->options; 26 va_list args; 27 28 printk(KERN_ERR "FAT: Filesystem error (dev %s)\n", s->s_id); 29 30 printk(KERN_ERR " "); 31 va_start(args, fmt); 32 vprintk(fmt, args); 33 va_end(args); 34 printk("\n"); 35 36 if (opts->errors == FAT_ERRORS_PANIC) 37 panic(" FAT fs panic from previous error\n"); 38 else if (opts->errors == FAT_ERRORS_RO && !(s->s_flags & MS_RDONLY)) { 39 s->s_flags |= MS_RDONLY; 40 printk(KERN_ERR " File system has been set read-only\n"); 41 } 42 } 43 EXPORT_SYMBOL_GPL(fat_fs_error); 44 45 /* Flushes the number of free clusters on FAT32 */ 46 /* XXX: Need to write one per FSINFO block. Currently only writes 1 */ 47 int fat_clusters_flush(struct super_block *sb) 48 { 49 struct msdos_sb_info *sbi = MSDOS_SB(sb); 50 struct buffer_head *bh; 51 struct fat_boot_fsinfo *fsinfo; 52 53 if (sbi->fat_bits != 32) 54 return 0; 55 56 bh = sb_bread(sb, sbi->fsinfo_sector); 57 if (bh == NULL) { 58 printk(KERN_ERR "FAT: bread failed in fat_clusters_flush\n"); 59 return -EIO; 60 } 61 62 fsinfo = (struct fat_boot_fsinfo *)bh->b_data; 63 /* Sanity check */ 64 if (!IS_FSINFO(fsinfo)) { 65 printk(KERN_ERR "FAT: Invalid FSINFO signature: " 66 "0x%08x, 0x%08x (sector = %lu)\n", 67 le32_to_cpu(fsinfo->signature1), 68 le32_to_cpu(fsinfo->signature2), 69 sbi->fsinfo_sector); 70 } else { 71 if (sbi->free_clusters != -1) 72 fsinfo->free_clusters = cpu_to_le32(sbi->free_clusters); 73 if (sbi->prev_free != -1) 74 fsinfo->next_cluster = cpu_to_le32(sbi->prev_free); 75 mark_buffer_dirty(bh); 76 } 77 brelse(bh); 78 79 return 0; 80 } 81 82 /* 83 * fat_chain_add() adds a new cluster to the chain of clusters represented 84 * by inode. 85 */ 86 int fat_chain_add(struct inode *inode, int new_dclus, int nr_cluster) 87 { 88 struct super_block *sb = inode->i_sb; 89 struct msdos_sb_info *sbi = MSDOS_SB(sb); 90 int ret, new_fclus, last; 91 92 /* 93 * We must locate the last cluster of the file to add this new 94 * one (new_dclus) to the end of the link list (the FAT). 95 */ 96 last = new_fclus = 0; 97 if (MSDOS_I(inode)->i_start) { 98 int fclus, dclus; 99 100 ret = fat_get_cluster(inode, FAT_ENT_EOF, &fclus, &dclus); 101 if (ret < 0) 102 return ret; 103 new_fclus = fclus + 1; 104 last = dclus; 105 } 106 107 /* add new one to the last of the cluster chain */ 108 if (last) { 109 struct fat_entry fatent; 110 111 fatent_init(&fatent); 112 ret = fat_ent_read(inode, &fatent, last); 113 if (ret >= 0) { 114 int wait = inode_needs_sync(inode); 115 ret = fat_ent_write(inode, &fatent, new_dclus, wait); 116 fatent_brelse(&fatent); 117 } 118 if (ret < 0) 119 return ret; 120 // fat_cache_add(inode, new_fclus, new_dclus); 121 } else { 122 MSDOS_I(inode)->i_start = new_dclus; 123 MSDOS_I(inode)->i_logstart = new_dclus; 124 /* 125 * Since generic_write_sync() synchronizes regular files later, 126 * we sync here only directories. 127 */ 128 if (S_ISDIR(inode->i_mode) && IS_DIRSYNC(inode)) { 129 ret = fat_sync_inode(inode); 130 if (ret) 131 return ret; 132 } else 133 mark_inode_dirty(inode); 134 } 135 if (new_fclus != (inode->i_blocks >> (sbi->cluster_bits - 9))) { 136 fat_fs_error(sb, "clusters badly computed (%d != %llu)", 137 new_fclus, 138 (llu)(inode->i_blocks >> (sbi->cluster_bits - 9))); 139 fat_cache_inval_inode(inode); 140 } 141 inode->i_blocks += nr_cluster << (sbi->cluster_bits - 9); 142 143 return 0; 144 } 145 146 extern struct timezone sys_tz; 147 148 /* 149 * The epoch of FAT timestamp is 1980. 150 * : bits : value 151 * date: 0 - 4: day (1 - 31) 152 * date: 5 - 8: month (1 - 12) 153 * date: 9 - 15: year (0 - 127) from 1980 154 * time: 0 - 4: sec (0 - 29) 2sec counts 155 * time: 5 - 10: min (0 - 59) 156 * time: 11 - 15: hour (0 - 23) 157 */ 158 #define SECS_PER_MIN 60 159 #define SECS_PER_HOUR (60 * 60) 160 #define SECS_PER_DAY (SECS_PER_HOUR * 24) 161 /* days between 1.1.70 and 1.1.80 (2 leap days) */ 162 #define DAYS_DELTA (365 * 10 + 2) 163 /* 120 (2100 - 1980) isn't leap year */ 164 #define YEAR_2100 120 165 #define IS_LEAP_YEAR(y) (!((y) & 3) && (y) != YEAR_2100) 166 167 /* Linear day numbers of the respective 1sts in non-leap years. */ 168 static time_t days_in_year[] = { 169 /* Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec */ 170 0, 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 0, 0, 0, 171 }; 172 173 /* Convert a FAT time/date pair to a UNIX date (seconds since 1 1 70). */ 174 void fat_time_fat2unix(struct msdos_sb_info *sbi, struct timespec *ts, 175 __le16 __time, __le16 __date, u8 time_cs) 176 { 177 u16 time = le16_to_cpu(__time), date = le16_to_cpu(__date); 178 time_t second, day, leap_day, month, year; 179 180 year = date >> 9; 181 month = max(1, (date >> 5) & 0xf); 182 day = max(1, date & 0x1f) - 1; 183 184 leap_day = (year + 3) / 4; 185 if (year > YEAR_2100) /* 2100 isn't leap year */ 186 leap_day--; 187 if (IS_LEAP_YEAR(year) && month > 2) 188 leap_day++; 189 190 second = (time & 0x1f) << 1; 191 second += ((time >> 5) & 0x3f) * SECS_PER_MIN; 192 second += (time >> 11) * SECS_PER_HOUR; 193 second += (year * 365 + leap_day 194 + days_in_year[month] + day 195 + DAYS_DELTA) * SECS_PER_DAY; 196 197 if (!sbi->options.tz_utc) 198 second += sys_tz.tz_minuteswest * SECS_PER_MIN; 199 200 if (time_cs) { 201 ts->tv_sec = second + (time_cs / 100); 202 ts->tv_nsec = (time_cs % 100) * 10000000; 203 } else { 204 ts->tv_sec = second; 205 ts->tv_nsec = 0; 206 } 207 } 208 209 /* Convert linear UNIX date to a FAT time/date pair. */ 210 void fat_time_unix2fat(struct msdos_sb_info *sbi, struct timespec *ts, 211 __le16 *time, __le16 *date, u8 *time_cs) 212 { 213 struct tm tm; 214 time_to_tm(ts->tv_sec, sbi->options.tz_utc ? 0 : 215 -sys_tz.tz_minuteswest * 60, &tm); 216 217 /* FAT can only support year between 1980 to 2107 */ 218 if (tm.tm_year < 1980 - 1900) { 219 *time = 0; 220 *date = cpu_to_le16((0 << 9) | (1 << 5) | 1); 221 if (time_cs) 222 *time_cs = 0; 223 return; 224 } 225 if (tm.tm_year > 2107 - 1900) { 226 *time = cpu_to_le16((23 << 11) | (59 << 5) | 29); 227 *date = cpu_to_le16((127 << 9) | (12 << 5) | 31); 228 if (time_cs) 229 *time_cs = 199; 230 return; 231 } 232 233 /* from 1900 -> from 1980 */ 234 tm.tm_year -= 80; 235 /* 0~11 -> 1~12 */ 236 tm.tm_mon++; 237 /* 0~59 -> 0~29(2sec counts) */ 238 tm.tm_sec >>= 1; 239 240 *time = cpu_to_le16(tm.tm_hour << 11 | tm.tm_min << 5 | tm.tm_sec); 241 *date = cpu_to_le16(tm.tm_year << 9 | tm.tm_mon << 5 | tm.tm_mday); 242 if (time_cs) 243 *time_cs = (ts->tv_sec & 1) * 100 + ts->tv_nsec / 10000000; 244 } 245 EXPORT_SYMBOL_GPL(fat_time_unix2fat); 246 247 int fat_sync_bhs(struct buffer_head **bhs, int nr_bhs) 248 { 249 int i, err = 0; 250 251 ll_rw_block(SWRITE, nr_bhs, bhs); 252 for (i = 0; i < nr_bhs; i++) { 253 wait_on_buffer(bhs[i]); 254 if (buffer_eopnotsupp(bhs[i])) { 255 clear_buffer_eopnotsupp(bhs[i]); 256 err = -EOPNOTSUPP; 257 } else if (!err && !buffer_uptodate(bhs[i])) 258 err = -EIO; 259 } 260 return err; 261 } 262