1// SPDX-License-Identifier: GPL-2.0-only 2/* 3 * linux/fs/fat/misc.c 4 * 5 * Written 1992,1993 by Werner Almesberger 6 * 22/11/2000 - Fixed fat_date_unix2dos for dates earlier than 01/01/1980 7 * and date_dos2unix for date==0 by Igor Zhbanov(bsg@uniyar.ac.ru) 8 */ 9 10#include "fat.h" 11#include <linux/iversion.h> 12 13/* 14 * fat_fs_error reports a file system problem that might indicate fa data 15 * corruption/inconsistency. Depending on 'errors' mount option the 16 * panic() is called, or error message is printed FAT and nothing is done, 17 * or filesystem is remounted read-only (default behavior). 18 * In case the file system is remounted read-only, it can be made writable 19 * again by remounting it. 20 */ 21void __fat_fs_error(struct super_block *sb, int report, const char *fmt, ...) 22{ 23 struct fat_mount_options *opts = &MSDOS_SB(sb)->options; 24 va_list args; 25 struct va_format vaf; 26 27 if (report) { 28 va_start(args, fmt); 29 vaf.fmt = fmt; 30 vaf.va = &args; 31 fat_msg(sb, KERN_ERR, "error, %pV", &vaf); 32 va_end(args); 33 } 34 35 if (opts->errors == FAT_ERRORS_PANIC) 36 panic("FAT-fs (%s): fs panic from previous error\n", sb->s_id); 37 else if (opts->errors == FAT_ERRORS_RO && !sb_rdonly(sb)) { 38 sb->s_flags |= SB_RDONLY; 39 fat_msg(sb, KERN_ERR, "Filesystem has been set read-only"); 40 } 41} 42EXPORT_SYMBOL_GPL(__fat_fs_error); 43 44/** 45 * fat_msg() - print preformated FAT specific messages. Every thing what is 46 * not fat_fs_error() should be fat_msg(). 47 */ 48void fat_msg(struct super_block *sb, const char *level, const char *fmt, ...) 49{ 50 struct va_format vaf; 51 va_list args; 52 53 va_start(args, fmt); 54 vaf.fmt = fmt; 55 vaf.va = &args; 56 printk("%sFAT-fs (%s): %pV\n", level, sb->s_id, &vaf); 57 va_end(args); 58} 59 60/* Flushes the number of free clusters on FAT32 */ 61/* XXX: Need to write one per FSINFO block. Currently only writes 1 */ 62int fat_clusters_flush(struct super_block *sb) 63{ 64 struct msdos_sb_info *sbi = MSDOS_SB(sb); 65 struct buffer_head *bh; 66 struct fat_boot_fsinfo *fsinfo; 67 68 if (!is_fat32(sbi)) 69 return 0; 70 71 bh = sb_bread(sb, sbi->fsinfo_sector); 72 if (bh == NULL) { 73 fat_msg(sb, KERN_ERR, "bread failed in fat_clusters_flush"); 74 return -EIO; 75 } 76 77 fsinfo = (struct fat_boot_fsinfo *)bh->b_data; 78 /* Sanity check */ 79 if (!IS_FSINFO(fsinfo)) { 80 fat_msg(sb, KERN_ERR, "Invalid FSINFO signature: " 81 "0x%08x, 0x%08x (sector = %lu)", 82 le32_to_cpu(fsinfo->signature1), 83 le32_to_cpu(fsinfo->signature2), 84 sbi->fsinfo_sector); 85 } else { 86 if (sbi->free_clusters != -1) 87 fsinfo->free_clusters = cpu_to_le32(sbi->free_clusters); 88 if (sbi->prev_free != -1) 89 fsinfo->next_cluster = cpu_to_le32(sbi->prev_free); 90 mark_buffer_dirty(bh); 91 } 92 brelse(bh); 93 94 return 0; 95} 96 97/* 98 * fat_chain_add() adds a new cluster to the chain of clusters represented 99 * by inode. 100 */ 101int fat_chain_add(struct inode *inode, int new_dclus, int nr_cluster) 102{ 103 struct super_block *sb = inode->i_sb; 104 struct msdos_sb_info *sbi = MSDOS_SB(sb); 105 int ret, new_fclus, last; 106 107 /* 108 * We must locate the last cluster of the file to add this new 109 * one (new_dclus) to the end of the link list (the FAT). 110 */ 111 last = new_fclus = 0; 112 if (MSDOS_I(inode)->i_start) { 113 int fclus, dclus; 114 115 ret = fat_get_cluster(inode, FAT_ENT_EOF, &fclus, &dclus); 116 if (ret < 0) 117 return ret; 118 new_fclus = fclus + 1; 119 last = dclus; 120 } 121 122 /* add new one to the last of the cluster chain */ 123 if (last) { 124 struct fat_entry fatent; 125 126 fatent_init(&fatent); 127 ret = fat_ent_read(inode, &fatent, last); 128 if (ret >= 0) { 129 int wait = inode_needs_sync(inode); 130 ret = fat_ent_write(inode, &fatent, new_dclus, wait); 131 fatent_brelse(&fatent); 132 } 133 if (ret < 0) 134 return ret; 135 /* 136 * FIXME:Although we can add this cache, fat_cache_add() is 137 * assuming to be called after linear search with fat_cache_id. 138 */ 139// fat_cache_add(inode, new_fclus, new_dclus); 140 } else { 141 MSDOS_I(inode)->i_start = new_dclus; 142 MSDOS_I(inode)->i_logstart = new_dclus; 143 /* 144 * Since generic_write_sync() synchronizes regular files later, 145 * we sync here only directories. 146 */ 147 if (S_ISDIR(inode->i_mode) && IS_DIRSYNC(inode)) { 148 ret = fat_sync_inode(inode); 149 if (ret) 150 return ret; 151 } else 152 mark_inode_dirty(inode); 153 } 154 if (new_fclus != (inode->i_blocks >> (sbi->cluster_bits - 9))) { 155 fat_fs_error(sb, "clusters badly computed (%d != %llu)", 156 new_fclus, 157 (llu)(inode->i_blocks >> (sbi->cluster_bits - 9))); 158 fat_cache_inval_inode(inode); 159 } 160 inode->i_blocks += nr_cluster << (sbi->cluster_bits - 9); 161 162 return 0; 163} 164 165/* 166 * The epoch of FAT timestamp is 1980. 167 * : bits : value 168 * date: 0 - 4: day (1 - 31) 169 * date: 5 - 8: month (1 - 12) 170 * date: 9 - 15: year (0 - 127) from 1980 171 * time: 0 - 4: sec (0 - 29) 2sec counts 172 * time: 5 - 10: min (0 - 59) 173 * time: 11 - 15: hour (0 - 23) 174 */ 175#define SECS_PER_MIN 60 176#define SECS_PER_HOUR (60 * 60) 177#define SECS_PER_DAY (SECS_PER_HOUR * 24) 178/* days between 1.1.70 and 1.1.80 (2 leap days) */ 179#define DAYS_DELTA (365 * 10 + 2) 180/* 120 (2100 - 1980) isn't leap year */ 181#define YEAR_2100 120 182#define IS_LEAP_YEAR(y) (!((y) & 3) && (y) != YEAR_2100) 183 184/* Linear day numbers of the respective 1sts in non-leap years. */ 185static long days_in_year[] = { 186 /* Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec */ 187 0, 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 0, 0, 0, 188}; 189 190static inline int fat_tz_offset(struct msdos_sb_info *sbi) 191{ 192 return (sbi->options.tz_set ? 193 -sbi->options.time_offset : 194 sys_tz.tz_minuteswest) * SECS_PER_MIN; 195} 196 197/* Convert a FAT time/date pair to a UNIX date (seconds since 1 1 70). */ 198void fat_time_fat2unix(struct msdos_sb_info *sbi, struct timespec64 *ts, 199 __le16 __time, __le16 __date, u8 time_cs) 200{ 201 u16 time = le16_to_cpu(__time), date = le16_to_cpu(__date); 202 time64_t second; 203 long day, leap_day, month, year; 204 205 year = date >> 9; 206 month = max(1, (date >> 5) & 0xf); 207 day = max(1, date & 0x1f) - 1; 208 209 leap_day = (year + 3) / 4; 210 if (year > YEAR_2100) /* 2100 isn't leap year */ 211 leap_day--; 212 if (IS_LEAP_YEAR(year) && month > 2) 213 leap_day++; 214 215 second = (time & 0x1f) << 1; 216 second += ((time >> 5) & 0x3f) * SECS_PER_MIN; 217 second += (time >> 11) * SECS_PER_HOUR; 218 second += (time64_t)(year * 365 + leap_day 219 + days_in_year[month] + day 220 + DAYS_DELTA) * SECS_PER_DAY; 221 222 second += fat_tz_offset(sbi); 223 224 if (time_cs) { 225 ts->tv_sec = second + (time_cs / 100); 226 ts->tv_nsec = (time_cs % 100) * 10000000; 227 } else { 228 ts->tv_sec = second; 229 ts->tv_nsec = 0; 230 } 231} 232 233/* Convert linear UNIX date to a FAT time/date pair. */ 234void fat_time_unix2fat(struct msdos_sb_info *sbi, struct timespec64 *ts, 235 __le16 *time, __le16 *date, u8 *time_cs) 236{ 237 struct tm tm; 238 time64_to_tm(ts->tv_sec, -fat_tz_offset(sbi), &tm); 239 240 /* FAT can only support year between 1980 to 2107 */ 241 if (tm.tm_year < 1980 - 1900) { 242 *time = 0; 243 *date = cpu_to_le16((0 << 9) | (1 << 5) | 1); 244 if (time_cs) 245 *time_cs = 0; 246 return; 247 } 248 if (tm.tm_year > 2107 - 1900) { 249 *time = cpu_to_le16((23 << 11) | (59 << 5) | 29); 250 *date = cpu_to_le16((127 << 9) | (12 << 5) | 31); 251 if (time_cs) 252 *time_cs = 199; 253 return; 254 } 255 256 /* from 1900 -> from 1980 */ 257 tm.tm_year -= 80; 258 /* 0~11 -> 1~12 */ 259 tm.tm_mon++; 260 /* 0~59 -> 0~29(2sec counts) */ 261 tm.tm_sec >>= 1; 262 263 *time = cpu_to_le16(tm.tm_hour << 11 | tm.tm_min << 5 | tm.tm_sec); 264 *date = cpu_to_le16(tm.tm_year << 9 | tm.tm_mon << 5 | tm.tm_mday); 265 if (time_cs) 266 *time_cs = (ts->tv_sec & 1) * 100 + ts->tv_nsec / 10000000; 267} 268EXPORT_SYMBOL_GPL(fat_time_unix2fat); 269 270static inline struct timespec64 fat_timespec64_trunc_2secs(struct timespec64 ts) 271{ 272 return (struct timespec64){ ts.tv_sec & ~1ULL, 0 }; 273} 274 275static inline struct timespec64 fat_timespec64_trunc_10ms(struct timespec64 ts) 276{ 277 if (ts.tv_nsec) 278 ts.tv_nsec -= ts.tv_nsec % 10000000UL; 279 return ts; 280} 281 282/* 283 * truncate the various times with appropriate granularity: 284 * root inode: 285 * all times always 0 286 * all other inodes: 287 * mtime - 2 seconds 288 * ctime 289 * msdos - 2 seconds 290 * vfat - 10 milliseconds 291 * atime - 24 hours (00:00:00 in local timezone) 292 */ 293int fat_truncate_time(struct inode *inode, struct timespec64 *now, int flags) 294{ 295 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb); 296 struct timespec64 ts; 297 298 if (inode->i_ino == MSDOS_ROOT_INO) 299 return 0; 300 301 if (now == NULL) { 302 now = &ts; 303 ts = current_time(inode); 304 } 305 306 if (flags & S_ATIME) { 307 /* to localtime */ 308 time64_t seconds = now->tv_sec - fat_tz_offset(sbi); 309 s32 remainder; 310 311 div_s64_rem(seconds, SECS_PER_DAY, &remainder); 312 /* to day boundary, and back to unix time */ 313 seconds = seconds + fat_tz_offset(sbi) - remainder; 314 315 inode->i_atime = (struct timespec64){ seconds, 0 }; 316 } 317 if (flags & S_CTIME) { 318 if (sbi->options.isvfat) 319 inode->i_ctime = fat_timespec64_trunc_10ms(*now); 320 else 321 inode->i_ctime = fat_timespec64_trunc_2secs(*now); 322 } 323 if (flags & S_MTIME) 324 inode->i_mtime = fat_timespec64_trunc_2secs(*now); 325 326 return 0; 327} 328EXPORT_SYMBOL_GPL(fat_truncate_time); 329 330int fat_update_time(struct inode *inode, struct timespec64 *now, int flags) 331{ 332 int iflags = I_DIRTY_TIME; 333 bool dirty = false; 334 335 if (inode->i_ino == MSDOS_ROOT_INO) 336 return 0; 337 338 fat_truncate_time(inode, now, flags); 339 if (flags & S_VERSION) 340 dirty = inode_maybe_inc_iversion(inode, false); 341 if ((flags & (S_ATIME | S_CTIME | S_MTIME)) && 342 !(inode->i_sb->s_flags & SB_LAZYTIME)) 343 dirty = true; 344 345 if (dirty) 346 iflags |= I_DIRTY_SYNC; 347 __mark_inode_dirty(inode, iflags); 348 return 0; 349} 350EXPORT_SYMBOL_GPL(fat_update_time); 351 352int fat_sync_bhs(struct buffer_head **bhs, int nr_bhs) 353{ 354 int i, err = 0; 355 356 for (i = 0; i < nr_bhs; i++) 357 write_dirty_buffer(bhs[i], 0); 358 359 for (i = 0; i < nr_bhs; i++) { 360 wait_on_buffer(bhs[i]); 361 if (!err && !buffer_uptodate(bhs[i])) 362 err = -EIO; 363 } 364 return err; 365} 366