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 *sb, int report, const char *fmt, ...) 24 { 25 struct fat_mount_options *opts = &MSDOS_SB(sb)->options; 26 va_list args; 27 struct va_format vaf; 28 29 if (report) { 30 va_start(args, fmt); 31 vaf.fmt = fmt; 32 vaf.va = &args; 33 fat_msg(sb, KERN_ERR, "error, %pV", &vaf); 34 va_end(args); 35 } 36 37 if (opts->errors == FAT_ERRORS_PANIC) 38 panic("FAT-fs (%s): fs panic from previous error\n", sb->s_id); 39 else if (opts->errors == FAT_ERRORS_RO && !(sb->s_flags & MS_RDONLY)) { 40 sb->s_flags |= MS_RDONLY; 41 fat_msg(sb, KERN_ERR, "Filesystem has been set read-only"); 42 } 43 } 44 EXPORT_SYMBOL_GPL(__fat_fs_error); 45 46 /** 47 * fat_msg() - print preformated FAT specific messages. Every thing what is 48 * not fat_fs_error() should be fat_msg(). 49 */ 50 void fat_msg(struct super_block *sb, const char *level, const char *fmt, ...) 51 { 52 struct va_format vaf; 53 va_list args; 54 55 va_start(args, fmt); 56 vaf.fmt = fmt; 57 vaf.va = &args; 58 printk("%sFAT-fs (%s): %pV\n", level, sb->s_id, &vaf); 59 va_end(args); 60 } 61 62 /* Flushes the number of free clusters on FAT32 */ 63 /* XXX: Need to write one per FSINFO block. Currently only writes 1 */ 64 int fat_clusters_flush(struct super_block *sb) 65 { 66 struct msdos_sb_info *sbi = MSDOS_SB(sb); 67 struct buffer_head *bh; 68 struct fat_boot_fsinfo *fsinfo; 69 70 if (sbi->fat_bits != 32) 71 return 0; 72 73 bh = sb_bread(sb, sbi->fsinfo_sector); 74 if (bh == NULL) { 75 fat_msg(sb, KERN_ERR, "bread failed in fat_clusters_flush"); 76 return -EIO; 77 } 78 79 fsinfo = (struct fat_boot_fsinfo *)bh->b_data; 80 /* Sanity check */ 81 if (!IS_FSINFO(fsinfo)) { 82 fat_msg(sb, KERN_ERR, "Invalid FSINFO signature: " 83 "0x%08x, 0x%08x (sector = %lu)", 84 le32_to_cpu(fsinfo->signature1), 85 le32_to_cpu(fsinfo->signature2), 86 sbi->fsinfo_sector); 87 } else { 88 if (sbi->free_clusters != -1) 89 fsinfo->free_clusters = cpu_to_le32(sbi->free_clusters); 90 if (sbi->prev_free != -1) 91 fsinfo->next_cluster = cpu_to_le32(sbi->prev_free); 92 mark_buffer_dirty(bh); 93 } 94 brelse(bh); 95 96 return 0; 97 } 98 99 /* 100 * fat_chain_add() adds a new cluster to the chain of clusters represented 101 * by inode. 102 */ 103 int fat_chain_add(struct inode *inode, int new_dclus, int nr_cluster) 104 { 105 struct super_block *sb = inode->i_sb; 106 struct msdos_sb_info *sbi = MSDOS_SB(sb); 107 int ret, new_fclus, last; 108 109 /* 110 * We must locate the last cluster of the file to add this new 111 * one (new_dclus) to the end of the link list (the FAT). 112 */ 113 last = new_fclus = 0; 114 if (MSDOS_I(inode)->i_start) { 115 int fclus, dclus; 116 117 ret = fat_get_cluster(inode, FAT_ENT_EOF, &fclus, &dclus); 118 if (ret < 0) 119 return ret; 120 new_fclus = fclus + 1; 121 last = dclus; 122 } 123 124 /* add new one to the last of the cluster chain */ 125 if (last) { 126 struct fat_entry fatent; 127 128 fatent_init(&fatent); 129 ret = fat_ent_read(inode, &fatent, last); 130 if (ret >= 0) { 131 int wait = inode_needs_sync(inode); 132 ret = fat_ent_write(inode, &fatent, new_dclus, wait); 133 fatent_brelse(&fatent); 134 } 135 if (ret < 0) 136 return ret; 137 /* 138 * FIXME:Although we can add this cache, fat_cache_add() is 139 * assuming to be called after linear search with fat_cache_id. 140 */ 141 // fat_cache_add(inode, new_fclus, new_dclus); 142 } else { 143 MSDOS_I(inode)->i_start = new_dclus; 144 MSDOS_I(inode)->i_logstart = new_dclus; 145 /* 146 * Since generic_write_sync() synchronizes regular files later, 147 * we sync here only directories. 148 */ 149 if (S_ISDIR(inode->i_mode) && IS_DIRSYNC(inode)) { 150 ret = fat_sync_inode(inode); 151 if (ret) 152 return ret; 153 } else 154 mark_inode_dirty(inode); 155 } 156 if (new_fclus != (inode->i_blocks >> (sbi->cluster_bits - 9))) { 157 fat_fs_error(sb, "clusters badly computed (%d != %llu)", 158 new_fclus, 159 (llu)(inode->i_blocks >> (sbi->cluster_bits - 9))); 160 fat_cache_inval_inode(inode); 161 } 162 inode->i_blocks += nr_cluster << (sbi->cluster_bits - 9); 163 164 return 0; 165 } 166 167 /* 168 * The epoch of FAT timestamp is 1980. 169 * : bits : value 170 * date: 0 - 4: day (1 - 31) 171 * date: 5 - 8: month (1 - 12) 172 * date: 9 - 15: year (0 - 127) from 1980 173 * time: 0 - 4: sec (0 - 29) 2sec counts 174 * time: 5 - 10: min (0 - 59) 175 * time: 11 - 15: hour (0 - 23) 176 */ 177 #define SECS_PER_MIN 60 178 #define SECS_PER_HOUR (60 * 60) 179 #define SECS_PER_DAY (SECS_PER_HOUR * 24) 180 /* days between 1.1.70 and 1.1.80 (2 leap days) */ 181 #define DAYS_DELTA (365 * 10 + 2) 182 /* 120 (2100 - 1980) isn't leap year */ 183 #define YEAR_2100 120 184 #define IS_LEAP_YEAR(y) (!((y) & 3) && (y) != YEAR_2100) 185 186 /* Linear day numbers of the respective 1sts in non-leap years. */ 187 static time_t days_in_year[] = { 188 /* Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec */ 189 0, 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 0, 0, 0, 190 }; 191 192 /* Convert a FAT time/date pair to a UNIX date (seconds since 1 1 70). */ 193 void fat_time_fat2unix(struct msdos_sb_info *sbi, struct timespec *ts, 194 __le16 __time, __le16 __date, u8 time_cs) 195 { 196 u16 time = le16_to_cpu(__time), date = le16_to_cpu(__date); 197 time_t second, day, leap_day, month, year; 198 199 year = date >> 9; 200 month = max(1, (date >> 5) & 0xf); 201 day = max(1, date & 0x1f) - 1; 202 203 leap_day = (year + 3) / 4; 204 if (year > YEAR_2100) /* 2100 isn't leap year */ 205 leap_day--; 206 if (IS_LEAP_YEAR(year) && month > 2) 207 leap_day++; 208 209 second = (time & 0x1f) << 1; 210 second += ((time >> 5) & 0x3f) * SECS_PER_MIN; 211 second += (time >> 11) * SECS_PER_HOUR; 212 second += (year * 365 + leap_day 213 + days_in_year[month] + day 214 + DAYS_DELTA) * SECS_PER_DAY; 215 216 if (!sbi->options.tz_set) 217 second += sys_tz.tz_minuteswest * SECS_PER_MIN; 218 else 219 second -= sbi->options.time_offset * SECS_PER_MIN; 220 221 if (time_cs) { 222 ts->tv_sec = second + (time_cs / 100); 223 ts->tv_nsec = (time_cs % 100) * 10000000; 224 } else { 225 ts->tv_sec = second; 226 ts->tv_nsec = 0; 227 } 228 } 229 230 /* Convert linear UNIX date to a FAT time/date pair. */ 231 void fat_time_unix2fat(struct msdos_sb_info *sbi, struct timespec *ts, 232 __le16 *time, __le16 *date, u8 *time_cs) 233 { 234 struct tm tm; 235 time_to_tm(ts->tv_sec, 236 (sbi->options.tz_set ? sbi->options.time_offset : 237 -sys_tz.tz_minuteswest) * SECS_PER_MIN, &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 int fat_sync_bhs(struct buffer_head **bhs, int nr_bhs) 270 { 271 int i, err = 0; 272 273 for (i = 0; i < nr_bhs; i++) 274 write_dirty_buffer(bhs[i], WRITE); 275 276 for (i = 0; i < nr_bhs; i++) { 277 wait_on_buffer(bhs[i]); 278 if (!err && !buffer_uptodate(bhs[i])) 279 err = -EIO; 280 } 281 return err; 282 } 283