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, int report, const char *fmt, ...) 24 { 25 struct fat_mount_options *opts = &MSDOS_SB(s)->options; 26 va_list args; 27 28 if (report) { 29 printk(KERN_ERR "FAT: Filesystem error (dev %s)\n", s->s_id); 30 31 printk(KERN_ERR " "); 32 va_start(args, fmt); 33 vprintk(fmt, args); 34 va_end(args); 35 printk("\n"); 36 } 37 38 if (opts->errors == FAT_ERRORS_PANIC) 39 panic("FAT: fs panic from previous error\n"); 40 else if (opts->errors == FAT_ERRORS_RO && !(s->s_flags & MS_RDONLY)) { 41 s->s_flags |= MS_RDONLY; 42 printk(KERN_ERR "FAT: Filesystem has been set read-only\n"); 43 } 44 } 45 EXPORT_SYMBOL_GPL(__fat_fs_error); 46 47 /* Flushes the number of free clusters on FAT32 */ 48 /* XXX: Need to write one per FSINFO block. Currently only writes 1 */ 49 int fat_clusters_flush(struct super_block *sb) 50 { 51 struct msdos_sb_info *sbi = MSDOS_SB(sb); 52 struct buffer_head *bh; 53 struct fat_boot_fsinfo *fsinfo; 54 55 if (sbi->fat_bits != 32) 56 return 0; 57 58 bh = sb_bread(sb, sbi->fsinfo_sector); 59 if (bh == NULL) { 60 printk(KERN_ERR "FAT: bread failed in fat_clusters_flush\n"); 61 return -EIO; 62 } 63 64 fsinfo = (struct fat_boot_fsinfo *)bh->b_data; 65 /* Sanity check */ 66 if (!IS_FSINFO(fsinfo)) { 67 printk(KERN_ERR "FAT: Invalid FSINFO signature: " 68 "0x%08x, 0x%08x (sector = %lu)\n", 69 le32_to_cpu(fsinfo->signature1), 70 le32_to_cpu(fsinfo->signature2), 71 sbi->fsinfo_sector); 72 } else { 73 if (sbi->free_clusters != -1) 74 fsinfo->free_clusters = cpu_to_le32(sbi->free_clusters); 75 if (sbi->prev_free != -1) 76 fsinfo->next_cluster = cpu_to_le32(sbi->prev_free); 77 mark_buffer_dirty(bh); 78 } 79 brelse(bh); 80 81 return 0; 82 } 83 84 /* 85 * fat_chain_add() adds a new cluster to the chain of clusters represented 86 * by inode. 87 */ 88 int fat_chain_add(struct inode *inode, int new_dclus, int nr_cluster) 89 { 90 struct super_block *sb = inode->i_sb; 91 struct msdos_sb_info *sbi = MSDOS_SB(sb); 92 int ret, new_fclus, last; 93 94 /* 95 * We must locate the last cluster of the file to add this new 96 * one (new_dclus) to the end of the link list (the FAT). 97 */ 98 last = new_fclus = 0; 99 if (MSDOS_I(inode)->i_start) { 100 int fclus, dclus; 101 102 ret = fat_get_cluster(inode, FAT_ENT_EOF, &fclus, &dclus); 103 if (ret < 0) 104 return ret; 105 new_fclus = fclus + 1; 106 last = dclus; 107 } 108 109 /* add new one to the last of the cluster chain */ 110 if (last) { 111 struct fat_entry fatent; 112 113 fatent_init(&fatent); 114 ret = fat_ent_read(inode, &fatent, last); 115 if (ret >= 0) { 116 int wait = inode_needs_sync(inode); 117 ret = fat_ent_write(inode, &fatent, new_dclus, wait); 118 fatent_brelse(&fatent); 119 } 120 if (ret < 0) 121 return ret; 122 // fat_cache_add(inode, new_fclus, new_dclus); 123 } else { 124 MSDOS_I(inode)->i_start = new_dclus; 125 MSDOS_I(inode)->i_logstart = new_dclus; 126 /* 127 * Since generic_write_sync() synchronizes regular files later, 128 * we sync here only directories. 129 */ 130 if (S_ISDIR(inode->i_mode) && IS_DIRSYNC(inode)) { 131 ret = fat_sync_inode(inode); 132 if (ret) 133 return ret; 134 } else 135 mark_inode_dirty(inode); 136 } 137 if (new_fclus != (inode->i_blocks >> (sbi->cluster_bits - 9))) { 138 fat_fs_error(sb, "clusters badly computed (%d != %llu)", 139 new_fclus, 140 (llu)(inode->i_blocks >> (sbi->cluster_bits - 9))); 141 fat_cache_inval_inode(inode); 142 } 143 inode->i_blocks += nr_cluster << (sbi->cluster_bits - 9); 144 145 return 0; 146 } 147 148 extern struct timezone sys_tz; 149 150 /* 151 * The epoch of FAT timestamp is 1980. 152 * : bits : value 153 * date: 0 - 4: day (1 - 31) 154 * date: 5 - 8: month (1 - 12) 155 * date: 9 - 15: year (0 - 127) from 1980 156 * time: 0 - 4: sec (0 - 29) 2sec counts 157 * time: 5 - 10: min (0 - 59) 158 * time: 11 - 15: hour (0 - 23) 159 */ 160 #define SECS_PER_MIN 60 161 #define SECS_PER_HOUR (60 * 60) 162 #define SECS_PER_DAY (SECS_PER_HOUR * 24) 163 /* days between 1.1.70 and 1.1.80 (2 leap days) */ 164 #define DAYS_DELTA (365 * 10 + 2) 165 /* 120 (2100 - 1980) isn't leap year */ 166 #define YEAR_2100 120 167 #define IS_LEAP_YEAR(y) (!((y) & 3) && (y) != YEAR_2100) 168 169 /* Linear day numbers of the respective 1sts in non-leap years. */ 170 static time_t days_in_year[] = { 171 /* Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec */ 172 0, 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 0, 0, 0, 173 }; 174 175 /* Convert a FAT time/date pair to a UNIX date (seconds since 1 1 70). */ 176 void fat_time_fat2unix(struct msdos_sb_info *sbi, struct timespec *ts, 177 __le16 __time, __le16 __date, u8 time_cs) 178 { 179 u16 time = le16_to_cpu(__time), date = le16_to_cpu(__date); 180 time_t second, day, leap_day, month, year; 181 182 year = date >> 9; 183 month = max(1, (date >> 5) & 0xf); 184 day = max(1, date & 0x1f) - 1; 185 186 leap_day = (year + 3) / 4; 187 if (year > YEAR_2100) /* 2100 isn't leap year */ 188 leap_day--; 189 if (IS_LEAP_YEAR(year) && month > 2) 190 leap_day++; 191 192 second = (time & 0x1f) << 1; 193 second += ((time >> 5) & 0x3f) * SECS_PER_MIN; 194 second += (time >> 11) * SECS_PER_HOUR; 195 second += (year * 365 + leap_day 196 + days_in_year[month] + day 197 + DAYS_DELTA) * SECS_PER_DAY; 198 199 if (!sbi->options.tz_utc) 200 second += sys_tz.tz_minuteswest * SECS_PER_MIN; 201 202 if (time_cs) { 203 ts->tv_sec = second + (time_cs / 100); 204 ts->tv_nsec = (time_cs % 100) * 10000000; 205 } else { 206 ts->tv_sec = second; 207 ts->tv_nsec = 0; 208 } 209 } 210 211 /* Convert linear UNIX date to a FAT time/date pair. */ 212 void fat_time_unix2fat(struct msdos_sb_info *sbi, struct timespec *ts, 213 __le16 *time, __le16 *date, u8 *time_cs) 214 { 215 struct tm tm; 216 time_to_tm(ts->tv_sec, sbi->options.tz_utc ? 0 : 217 -sys_tz.tz_minuteswest * 60, &tm); 218 219 /* FAT can only support year between 1980 to 2107 */ 220 if (tm.tm_year < 1980 - 1900) { 221 *time = 0; 222 *date = cpu_to_le16((0 << 9) | (1 << 5) | 1); 223 if (time_cs) 224 *time_cs = 0; 225 return; 226 } 227 if (tm.tm_year > 2107 - 1900) { 228 *time = cpu_to_le16((23 << 11) | (59 << 5) | 29); 229 *date = cpu_to_le16((127 << 9) | (12 << 5) | 31); 230 if (time_cs) 231 *time_cs = 199; 232 return; 233 } 234 235 /* from 1900 -> from 1980 */ 236 tm.tm_year -= 80; 237 /* 0~11 -> 1~12 */ 238 tm.tm_mon++; 239 /* 0~59 -> 0~29(2sec counts) */ 240 tm.tm_sec >>= 1; 241 242 *time = cpu_to_le16(tm.tm_hour << 11 | tm.tm_min << 5 | tm.tm_sec); 243 *date = cpu_to_le16(tm.tm_year << 9 | tm.tm_mon << 5 | tm.tm_mday); 244 if (time_cs) 245 *time_cs = (ts->tv_sec & 1) * 100 + ts->tv_nsec / 10000000; 246 } 247 EXPORT_SYMBOL_GPL(fat_time_unix2fat); 248 249 int fat_sync_bhs(struct buffer_head **bhs, int nr_bhs) 250 { 251 int i, err = 0; 252 253 for (i = 0; i < nr_bhs; i++) 254 write_dirty_buffer(bhs[i], WRITE); 255 256 for (i = 0; i < nr_bhs; i++) { 257 wait_on_buffer(bhs[i]); 258 if (buffer_eopnotsupp(bhs[i])) { 259 clear_buffer_eopnotsupp(bhs[i]); 260 err = -EOPNOTSUPP; 261 } else if (!err && !buffer_uptodate(bhs[i])) 262 err = -EIO; 263 } 264 return err; 265 } 266