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 #include <linux/iversion.h> 11 12 /* 13 * fat_fs_error reports a file system problem that might indicate fa data 14 * corruption/inconsistency. Depending on 'errors' mount option the 15 * panic() is called, or error message is printed FAT and nothing is done, 16 * or filesystem is remounted read-only (default behavior). 17 * In case the file system is remounted read-only, it can be made writable 18 * again by remounting it. 19 */ 20 void __fat_fs_error(struct super_block *sb, int report, const char *fmt, ...) 21 { 22 struct fat_mount_options *opts = &MSDOS_SB(sb)->options; 23 va_list args; 24 struct va_format vaf; 25 26 if (report) { 27 va_start(args, fmt); 28 vaf.fmt = fmt; 29 vaf.va = &args; 30 fat_msg(sb, KERN_ERR, "error, %pV", &vaf); 31 va_end(args); 32 } 33 34 if (opts->errors == FAT_ERRORS_PANIC) 35 panic("FAT-fs (%s): fs panic from previous error\n", sb->s_id); 36 else if (opts->errors == FAT_ERRORS_RO && !sb_rdonly(sb)) { 37 sb->s_flags |= SB_RDONLY; 38 fat_msg(sb, KERN_ERR, "Filesystem has been set read-only"); 39 } 40 } 41 EXPORT_SYMBOL_GPL(__fat_fs_error); 42 43 /** 44 * fat_msg() - print preformated FAT specific messages. Every thing what is 45 * not fat_fs_error() should be fat_msg(). 46 */ 47 void fat_msg(struct super_block *sb, const char *level, const char *fmt, ...) 48 { 49 struct va_format vaf; 50 va_list args; 51 52 va_start(args, fmt); 53 vaf.fmt = fmt; 54 vaf.va = &args; 55 printk("%sFAT-fs (%s): %pV\n", level, sb->s_id, &vaf); 56 va_end(args); 57 } 58 59 /* Flushes the number of free clusters on FAT32 */ 60 /* XXX: Need to write one per FSINFO block. Currently only writes 1 */ 61 int fat_clusters_flush(struct super_block *sb) 62 { 63 struct msdos_sb_info *sbi = MSDOS_SB(sb); 64 struct buffer_head *bh; 65 struct fat_boot_fsinfo *fsinfo; 66 67 if (!is_fat32(sbi)) 68 return 0; 69 70 bh = sb_bread(sb, sbi->fsinfo_sector); 71 if (bh == NULL) { 72 fat_msg(sb, KERN_ERR, "bread failed in fat_clusters_flush"); 73 return -EIO; 74 } 75 76 fsinfo = (struct fat_boot_fsinfo *)bh->b_data; 77 /* Sanity check */ 78 if (!IS_FSINFO(fsinfo)) { 79 fat_msg(sb, KERN_ERR, "Invalid FSINFO signature: " 80 "0x%08x, 0x%08x (sector = %lu)", 81 le32_to_cpu(fsinfo->signature1), 82 le32_to_cpu(fsinfo->signature2), 83 sbi->fsinfo_sector); 84 } else { 85 if (sbi->free_clusters != -1) 86 fsinfo->free_clusters = cpu_to_le32(sbi->free_clusters); 87 if (sbi->prev_free != -1) 88 fsinfo->next_cluster = cpu_to_le32(sbi->prev_free); 89 mark_buffer_dirty(bh); 90 } 91 brelse(bh); 92 93 return 0; 94 } 95 96 /* 97 * fat_chain_add() adds a new cluster to the chain of clusters represented 98 * by inode. 99 */ 100 int fat_chain_add(struct inode *inode, int new_dclus, int nr_cluster) 101 { 102 struct super_block *sb = inode->i_sb; 103 struct msdos_sb_info *sbi = MSDOS_SB(sb); 104 int ret, new_fclus, last; 105 106 /* 107 * We must locate the last cluster of the file to add this new 108 * one (new_dclus) to the end of the link list (the FAT). 109 */ 110 last = new_fclus = 0; 111 if (MSDOS_I(inode)->i_start) { 112 int fclus, dclus; 113 114 ret = fat_get_cluster(inode, FAT_ENT_EOF, &fclus, &dclus); 115 if (ret < 0) 116 return ret; 117 new_fclus = fclus + 1; 118 last = dclus; 119 } 120 121 /* add new one to the last of the cluster chain */ 122 if (last) { 123 struct fat_entry fatent; 124 125 fatent_init(&fatent); 126 ret = fat_ent_read(inode, &fatent, last); 127 if (ret >= 0) { 128 int wait = inode_needs_sync(inode); 129 ret = fat_ent_write(inode, &fatent, new_dclus, wait); 130 fatent_brelse(&fatent); 131 } 132 if (ret < 0) 133 return ret; 134 /* 135 * FIXME:Although we can add this cache, fat_cache_add() is 136 * assuming to be called after linear search with fat_cache_id. 137 */ 138 // fat_cache_add(inode, new_fclus, new_dclus); 139 } else { 140 MSDOS_I(inode)->i_start = new_dclus; 141 MSDOS_I(inode)->i_logstart = new_dclus; 142 /* 143 * Since generic_write_sync() synchronizes regular files later, 144 * we sync here only directories. 145 */ 146 if (S_ISDIR(inode->i_mode) && IS_DIRSYNC(inode)) { 147 ret = fat_sync_inode(inode); 148 if (ret) 149 return ret; 150 } else 151 mark_inode_dirty(inode); 152 } 153 if (new_fclus != (inode->i_blocks >> (sbi->cluster_bits - 9))) { 154 fat_fs_error(sb, "clusters badly computed (%d != %llu)", 155 new_fclus, 156 (llu)(inode->i_blocks >> (sbi->cluster_bits - 9))); 157 fat_cache_inval_inode(inode); 158 } 159 inode->i_blocks += nr_cluster << (sbi->cluster_bits - 9); 160 161 return 0; 162 } 163 164 /* 165 * The epoch of FAT timestamp is 1980. 166 * : bits : value 167 * date: 0 - 4: day (1 - 31) 168 * date: 5 - 8: month (1 - 12) 169 * date: 9 - 15: year (0 - 127) from 1980 170 * time: 0 - 4: sec (0 - 29) 2sec counts 171 * time: 5 - 10: min (0 - 59) 172 * time: 11 - 15: hour (0 - 23) 173 */ 174 #define SECS_PER_MIN 60 175 #define SECS_PER_HOUR (60 * 60) 176 #define SECS_PER_DAY (SECS_PER_HOUR * 24) 177 /* days between 1.1.70 and 1.1.80 (2 leap days) */ 178 #define DAYS_DELTA (365 * 10 + 2) 179 /* 120 (2100 - 1980) isn't leap year */ 180 #define YEAR_2100 120 181 #define IS_LEAP_YEAR(y) (!((y) & 3) && (y) != YEAR_2100) 182 183 /* Linear day numbers of the respective 1sts in non-leap years. */ 184 static long days_in_year[] = { 185 /* Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec */ 186 0, 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 0, 0, 0, 187 }; 188 189 static inline int fat_tz_offset(struct msdos_sb_info *sbi) 190 { 191 return (sbi->options.tz_set ? 192 -sbi->options.time_offset : 193 sys_tz.tz_minuteswest) * SECS_PER_MIN; 194 } 195 196 /* Convert a FAT time/date pair to a UNIX date (seconds since 1 1 70). */ 197 void fat_time_fat2unix(struct msdos_sb_info *sbi, struct timespec64 *ts, 198 __le16 __time, __le16 __date, u8 time_cs) 199 { 200 u16 time = le16_to_cpu(__time), date = le16_to_cpu(__date); 201 time64_t second; 202 long day, leap_day, month, year; 203 204 year = date >> 9; 205 month = max(1, (date >> 5) & 0xf); 206 day = max(1, date & 0x1f) - 1; 207 208 leap_day = (year + 3) / 4; 209 if (year > YEAR_2100) /* 2100 isn't leap year */ 210 leap_day--; 211 if (IS_LEAP_YEAR(year) && month > 2) 212 leap_day++; 213 214 second = (time & 0x1f) << 1; 215 second += ((time >> 5) & 0x3f) * SECS_PER_MIN; 216 second += (time >> 11) * SECS_PER_HOUR; 217 second += (time64_t)(year * 365 + leap_day 218 + days_in_year[month] + day 219 + DAYS_DELTA) * SECS_PER_DAY; 220 221 second += fat_tz_offset(sbi); 222 223 if (time_cs) { 224 ts->tv_sec = second + (time_cs / 100); 225 ts->tv_nsec = (time_cs % 100) * 10000000; 226 } else { 227 ts->tv_sec = second; 228 ts->tv_nsec = 0; 229 } 230 } 231 232 /* Convert linear UNIX date to a FAT time/date pair. */ 233 void fat_time_unix2fat(struct msdos_sb_info *sbi, struct timespec64 *ts, 234 __le16 *time, __le16 *date, u8 *time_cs) 235 { 236 struct tm tm; 237 time64_to_tm(ts->tv_sec, -fat_tz_offset(sbi), &tm); 238 239 /* FAT can only support year between 1980 to 2107 */ 240 if (tm.tm_year < 1980 - 1900) { 241 *time = 0; 242 *date = cpu_to_le16((0 << 9) | (1 << 5) | 1); 243 if (time_cs) 244 *time_cs = 0; 245 return; 246 } 247 if (tm.tm_year > 2107 - 1900) { 248 *time = cpu_to_le16((23 << 11) | (59 << 5) | 29); 249 *date = cpu_to_le16((127 << 9) | (12 << 5) | 31); 250 if (time_cs) 251 *time_cs = 199; 252 return; 253 } 254 255 /* from 1900 -> from 1980 */ 256 tm.tm_year -= 80; 257 /* 0~11 -> 1~12 */ 258 tm.tm_mon++; 259 /* 0~59 -> 0~29(2sec counts) */ 260 tm.tm_sec >>= 1; 261 262 *time = cpu_to_le16(tm.tm_hour << 11 | tm.tm_min << 5 | tm.tm_sec); 263 *date = cpu_to_le16(tm.tm_year << 9 | tm.tm_mon << 5 | tm.tm_mday); 264 if (time_cs) 265 *time_cs = (ts->tv_sec & 1) * 100 + ts->tv_nsec / 10000000; 266 } 267 EXPORT_SYMBOL_GPL(fat_time_unix2fat); 268 269 static inline struct timespec64 fat_timespec64_trunc_2secs(struct timespec64 ts) 270 { 271 return (struct timespec64){ ts.tv_sec & ~1ULL, 0 }; 272 } 273 /* 274 * truncate the various times with appropriate granularity: 275 * root inode: 276 * all times always 0 277 * all other inodes: 278 * mtime - 2 seconds 279 * ctime 280 * msdos - 2 seconds 281 * vfat - 10 milliseconds 282 * atime - 24 hours (00:00:00 in local timezone) 283 */ 284 int fat_truncate_time(struct inode *inode, struct timespec64 *now, int flags) 285 { 286 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb); 287 struct timespec64 ts; 288 289 if (inode->i_ino == MSDOS_ROOT_INO) 290 return 0; 291 292 if (now == NULL) { 293 now = &ts; 294 ts = current_time(inode); 295 } 296 297 if (flags & S_ATIME) { 298 /* to localtime */ 299 time64_t seconds = now->tv_sec - fat_tz_offset(sbi); 300 s32 remainder; 301 302 div_s64_rem(seconds, SECS_PER_DAY, &remainder); 303 /* to day boundary, and back to unix time */ 304 seconds = seconds + fat_tz_offset(sbi) - remainder; 305 306 inode->i_atime = (struct timespec64){ seconds, 0 }; 307 } 308 if (flags & S_CTIME) { 309 if (sbi->options.isvfat) 310 inode->i_ctime = timespec64_trunc(*now, 10000000); 311 else 312 inode->i_ctime = fat_timespec64_trunc_2secs(*now); 313 } 314 if (flags & S_MTIME) 315 inode->i_mtime = fat_timespec64_trunc_2secs(*now); 316 317 return 0; 318 } 319 EXPORT_SYMBOL_GPL(fat_truncate_time); 320 321 int fat_update_time(struct inode *inode, struct timespec64 *now, int flags) 322 { 323 int iflags = I_DIRTY_TIME; 324 bool dirty = false; 325 326 if (inode->i_ino == MSDOS_ROOT_INO) 327 return 0; 328 329 fat_truncate_time(inode, now, flags); 330 if (flags & S_VERSION) 331 dirty = inode_maybe_inc_iversion(inode, false); 332 if ((flags & (S_ATIME | S_CTIME | S_MTIME)) && 333 !(inode->i_sb->s_flags & SB_LAZYTIME)) 334 dirty = true; 335 336 if (dirty) 337 iflags |= I_DIRTY_SYNC; 338 __mark_inode_dirty(inode, iflags); 339 return 0; 340 } 341 EXPORT_SYMBOL_GPL(fat_update_time); 342 343 int fat_sync_bhs(struct buffer_head **bhs, int nr_bhs) 344 { 345 int i, err = 0; 346 347 for (i = 0; i < nr_bhs; i++) 348 write_dirty_buffer(bhs[i], 0); 349 350 for (i = 0; i < nr_bhs; i++) { 351 wait_on_buffer(bhs[i]); 352 if (!err && !buffer_uptodate(bhs[i])) 353 err = -EIO; 354 } 355 return err; 356 } 357