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 "fat.h" 10 11 /* 12 * fat_fs_error reports a file system problem that might indicate fa data 13 * corruption/inconsistency. Depending on 'errors' mount option the 14 * panic() is called, or error message is printed FAT and nothing is done, 15 * or filesystem is remounted read-only (default behavior). 16 * In case the file system is remounted read-only, it can be made writable 17 * again by remounting it. 18 */ 19 void __fat_fs_error(struct super_block *sb, int report, const char *fmt, ...) 20 { 21 struct fat_mount_options *opts = &MSDOS_SB(sb)->options; 22 va_list args; 23 struct va_format vaf; 24 25 if (report) { 26 va_start(args, fmt); 27 vaf.fmt = fmt; 28 vaf.va = &args; 29 fat_msg(sb, KERN_ERR, "error, %pV", &vaf); 30 va_end(args); 31 } 32 33 if (opts->errors == FAT_ERRORS_PANIC) 34 panic("FAT-fs (%s): fs panic from previous error\n", sb->s_id); 35 else if (opts->errors == FAT_ERRORS_RO && !sb_rdonly(sb)) { 36 sb->s_flags |= SB_RDONLY; 37 fat_msg(sb, KERN_ERR, "Filesystem has been set read-only"); 38 } 39 } 40 EXPORT_SYMBOL_GPL(__fat_fs_error); 41 42 /** 43 * fat_msg() - print preformated FAT specific messages. Every thing what is 44 * not fat_fs_error() should be fat_msg(). 45 */ 46 void fat_msg(struct super_block *sb, const char *level, const char *fmt, ...) 47 { 48 struct va_format vaf; 49 va_list args; 50 51 va_start(args, fmt); 52 vaf.fmt = fmt; 53 vaf.va = &args; 54 printk("%sFAT-fs (%s): %pV\n", level, sb->s_id, &vaf); 55 va_end(args); 56 } 57 58 /* Flushes the number of free clusters on FAT32 */ 59 /* XXX: Need to write one per FSINFO block. Currently only writes 1 */ 60 int fat_clusters_flush(struct super_block *sb) 61 { 62 struct msdos_sb_info *sbi = MSDOS_SB(sb); 63 struct buffer_head *bh; 64 struct fat_boot_fsinfo *fsinfo; 65 66 if (sbi->fat_bits != 32) 67 return 0; 68 69 bh = sb_bread(sb, sbi->fsinfo_sector); 70 if (bh == NULL) { 71 fat_msg(sb, KERN_ERR, "bread failed in fat_clusters_flush"); 72 return -EIO; 73 } 74 75 fsinfo = (struct fat_boot_fsinfo *)bh->b_data; 76 /* Sanity check */ 77 if (!IS_FSINFO(fsinfo)) { 78 fat_msg(sb, KERN_ERR, "Invalid FSINFO signature: " 79 "0x%08x, 0x%08x (sector = %lu)", 80 le32_to_cpu(fsinfo->signature1), 81 le32_to_cpu(fsinfo->signature2), 82 sbi->fsinfo_sector); 83 } else { 84 if (sbi->free_clusters != -1) 85 fsinfo->free_clusters = cpu_to_le32(sbi->free_clusters); 86 if (sbi->prev_free != -1) 87 fsinfo->next_cluster = cpu_to_le32(sbi->prev_free); 88 mark_buffer_dirty(bh); 89 } 90 brelse(bh); 91 92 return 0; 93 } 94 95 /* 96 * fat_chain_add() adds a new cluster to the chain of clusters represented 97 * by inode. 98 */ 99 int fat_chain_add(struct inode *inode, int new_dclus, int nr_cluster) 100 { 101 struct super_block *sb = inode->i_sb; 102 struct msdos_sb_info *sbi = MSDOS_SB(sb); 103 int ret, new_fclus, last; 104 105 /* 106 * We must locate the last cluster of the file to add this new 107 * one (new_dclus) to the end of the link list (the FAT). 108 */ 109 last = new_fclus = 0; 110 if (MSDOS_I(inode)->i_start) { 111 int fclus, dclus; 112 113 ret = fat_get_cluster(inode, FAT_ENT_EOF, &fclus, &dclus); 114 if (ret < 0) 115 return ret; 116 new_fclus = fclus + 1; 117 last = dclus; 118 } 119 120 /* add new one to the last of the cluster chain */ 121 if (last) { 122 struct fat_entry fatent; 123 124 fatent_init(&fatent); 125 ret = fat_ent_read(inode, &fatent, last); 126 if (ret >= 0) { 127 int wait = inode_needs_sync(inode); 128 ret = fat_ent_write(inode, &fatent, new_dclus, wait); 129 fatent_brelse(&fatent); 130 } 131 if (ret < 0) 132 return ret; 133 /* 134 * FIXME:Although we can add this cache, fat_cache_add() is 135 * assuming to be called after linear search with fat_cache_id. 136 */ 137 // fat_cache_add(inode, new_fclus, new_dclus); 138 } else { 139 MSDOS_I(inode)->i_start = new_dclus; 140 MSDOS_I(inode)->i_logstart = new_dclus; 141 /* 142 * Since generic_write_sync() synchronizes regular files later, 143 * we sync here only directories. 144 */ 145 if (S_ISDIR(inode->i_mode) && IS_DIRSYNC(inode)) { 146 ret = fat_sync_inode(inode); 147 if (ret) 148 return ret; 149 } else 150 mark_inode_dirty(inode); 151 } 152 if (new_fclus != (inode->i_blocks >> (sbi->cluster_bits - 9))) { 153 fat_fs_error(sb, "clusters badly computed (%d != %llu)", 154 new_fclus, 155 (llu)(inode->i_blocks >> (sbi->cluster_bits - 9))); 156 fat_cache_inval_inode(inode); 157 } 158 inode->i_blocks += nr_cluster << (sbi->cluster_bits - 9); 159 160 return 0; 161 } 162 163 /* 164 * The epoch of FAT timestamp is 1980. 165 * : bits : value 166 * date: 0 - 4: day (1 - 31) 167 * date: 5 - 8: month (1 - 12) 168 * date: 9 - 15: year (0 - 127) from 1980 169 * time: 0 - 4: sec (0 - 29) 2sec counts 170 * time: 5 - 10: min (0 - 59) 171 * time: 11 - 15: hour (0 - 23) 172 */ 173 #define SECS_PER_MIN 60 174 #define SECS_PER_HOUR (60 * 60) 175 #define SECS_PER_DAY (SECS_PER_HOUR * 24) 176 /* days between 1.1.70 and 1.1.80 (2 leap days) */ 177 #define DAYS_DELTA (365 * 10 + 2) 178 /* 120 (2100 - 1980) isn't leap year */ 179 #define YEAR_2100 120 180 #define IS_LEAP_YEAR(y) (!((y) & 3) && (y) != YEAR_2100) 181 182 /* Linear day numbers of the respective 1sts in non-leap years. */ 183 static long days_in_year[] = { 184 /* Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec */ 185 0, 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 0, 0, 0, 186 }; 187 188 /* Convert a FAT time/date pair to a UNIX date (seconds since 1 1 70). */ 189 void fat_time_fat2unix(struct msdos_sb_info *sbi, struct timespec64 *ts, 190 __le16 __time, __le16 __date, u8 time_cs) 191 { 192 u16 time = le16_to_cpu(__time), date = le16_to_cpu(__date); 193 time64_t second; 194 long day, leap_day, month, year; 195 196 year = date >> 9; 197 month = max(1, (date >> 5) & 0xf); 198 day = max(1, date & 0x1f) - 1; 199 200 leap_day = (year + 3) / 4; 201 if (year > YEAR_2100) /* 2100 isn't leap year */ 202 leap_day--; 203 if (IS_LEAP_YEAR(year) && month > 2) 204 leap_day++; 205 206 second = (time & 0x1f) << 1; 207 second += ((time >> 5) & 0x3f) * SECS_PER_MIN; 208 second += (time >> 11) * SECS_PER_HOUR; 209 second += (time64_t)(year * 365 + leap_day 210 + days_in_year[month] + day 211 + DAYS_DELTA) * SECS_PER_DAY; 212 213 if (!sbi->options.tz_set) 214 second += sys_tz.tz_minuteswest * SECS_PER_MIN; 215 else 216 second -= sbi->options.time_offset * SECS_PER_MIN; 217 218 if (time_cs) { 219 ts->tv_sec = second + (time_cs / 100); 220 ts->tv_nsec = (time_cs % 100) * 10000000; 221 } else { 222 ts->tv_sec = second; 223 ts->tv_nsec = 0; 224 } 225 } 226 227 /* Convert linear UNIX date to a FAT time/date pair. */ 228 void fat_time_unix2fat(struct msdos_sb_info *sbi, struct timespec64 *ts, 229 __le16 *time, __le16 *date, u8 *time_cs) 230 { 231 struct tm tm; 232 time64_to_tm(ts->tv_sec, 233 (sbi->options.tz_set ? sbi->options.time_offset : 234 -sys_tz.tz_minuteswest) * SECS_PER_MIN, &tm); 235 236 /* FAT can only support year between 1980 to 2107 */ 237 if (tm.tm_year < 1980 - 1900) { 238 *time = 0; 239 *date = cpu_to_le16((0 << 9) | (1 << 5) | 1); 240 if (time_cs) 241 *time_cs = 0; 242 return; 243 } 244 if (tm.tm_year > 2107 - 1900) { 245 *time = cpu_to_le16((23 << 11) | (59 << 5) | 29); 246 *date = cpu_to_le16((127 << 9) | (12 << 5) | 31); 247 if (time_cs) 248 *time_cs = 199; 249 return; 250 } 251 252 /* from 1900 -> from 1980 */ 253 tm.tm_year -= 80; 254 /* 0~11 -> 1~12 */ 255 tm.tm_mon++; 256 /* 0~59 -> 0~29(2sec counts) */ 257 tm.tm_sec >>= 1; 258 259 *time = cpu_to_le16(tm.tm_hour << 11 | tm.tm_min << 5 | tm.tm_sec); 260 *date = cpu_to_le16(tm.tm_year << 9 | tm.tm_mon << 5 | tm.tm_mday); 261 if (time_cs) 262 *time_cs = (ts->tv_sec & 1) * 100 + ts->tv_nsec / 10000000; 263 } 264 EXPORT_SYMBOL_GPL(fat_time_unix2fat); 265 266 int fat_sync_bhs(struct buffer_head **bhs, int nr_bhs) 267 { 268 int i, err = 0; 269 270 for (i = 0; i < nr_bhs; i++) 271 write_dirty_buffer(bhs[i], 0); 272 273 for (i = 0; i < nr_bhs; i++) { 274 wait_on_buffer(bhs[i]); 275 if (!err && !buffer_uptodate(bhs[i])) 276 err = -EIO; 277 } 278 return err; 279 } 280