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 printk(KERN_ERR "FAT-fs (%s): error, %pV\n", sb->s_id, &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 printk(KERN_ERR "FAT-fs (%s): Filesystem has been " 42 "set read-only\n", sb->s_id); 43 } 44 } 45 EXPORT_SYMBOL_GPL(__fat_fs_error); 46 47 /** 48 * fat_msg() - print preformated FAT specific messages. Every thing what is 49 * not fat_fs_error() should be fat_msg(). 50 */ 51 void fat_msg(struct super_block *sb, const char *level, const char *fmt, ...) 52 { 53 struct va_format vaf; 54 va_list args; 55 56 va_start(args, fmt); 57 vaf.fmt = fmt; 58 vaf.va = &args; 59 printk("%sFAT-fs (%s): %pV\n", level, sb->s_id, &vaf); 60 va_end(args); 61 } 62 63 /* Flushes the number of free clusters on FAT32 */ 64 /* XXX: Need to write one per FSINFO block. Currently only writes 1 */ 65 int fat_clusters_flush(struct super_block *sb) 66 { 67 struct msdos_sb_info *sbi = MSDOS_SB(sb); 68 struct buffer_head *bh; 69 struct fat_boot_fsinfo *fsinfo; 70 71 if (sbi->fat_bits != 32) 72 return 0; 73 74 bh = sb_bread(sb, sbi->fsinfo_sector); 75 if (bh == NULL) { 76 fat_msg(sb, KERN_ERR, "bread failed in fat_clusters_flush"); 77 return -EIO; 78 } 79 80 fsinfo = (struct fat_boot_fsinfo *)bh->b_data; 81 /* Sanity check */ 82 if (!IS_FSINFO(fsinfo)) { 83 fat_msg(sb, KERN_ERR, "Invalid FSINFO signature: " 84 "0x%08x, 0x%08x (sector = %lu)", 85 le32_to_cpu(fsinfo->signature1), 86 le32_to_cpu(fsinfo->signature2), 87 sbi->fsinfo_sector); 88 } else { 89 if (sbi->free_clusters != -1) 90 fsinfo->free_clusters = cpu_to_le32(sbi->free_clusters); 91 if (sbi->prev_free != -1) 92 fsinfo->next_cluster = cpu_to_le32(sbi->prev_free); 93 mark_buffer_dirty(bh); 94 } 95 brelse(bh); 96 97 return 0; 98 } 99 100 /* 101 * fat_chain_add() adds a new cluster to the chain of clusters represented 102 * by inode. 103 */ 104 int fat_chain_add(struct inode *inode, int new_dclus, int nr_cluster) 105 { 106 struct super_block *sb = inode->i_sb; 107 struct msdos_sb_info *sbi = MSDOS_SB(sb); 108 int ret, new_fclus, last; 109 110 /* 111 * We must locate the last cluster of the file to add this new 112 * one (new_dclus) to the end of the link list (the FAT). 113 */ 114 last = new_fclus = 0; 115 if (MSDOS_I(inode)->i_start) { 116 int fclus, dclus; 117 118 ret = fat_get_cluster(inode, FAT_ENT_EOF, &fclus, &dclus); 119 if (ret < 0) 120 return ret; 121 new_fclus = fclus + 1; 122 last = dclus; 123 } 124 125 /* add new one to the last of the cluster chain */ 126 if (last) { 127 struct fat_entry fatent; 128 129 fatent_init(&fatent); 130 ret = fat_ent_read(inode, &fatent, last); 131 if (ret >= 0) { 132 int wait = inode_needs_sync(inode); 133 ret = fat_ent_write(inode, &fatent, new_dclus, wait); 134 fatent_brelse(&fatent); 135 } 136 if (ret < 0) 137 return ret; 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 extern struct timezone sys_tz; 165 166 /* 167 * The epoch of FAT timestamp is 1980. 168 * : bits : value 169 * date: 0 - 4: day (1 - 31) 170 * date: 5 - 8: month (1 - 12) 171 * date: 9 - 15: year (0 - 127) from 1980 172 * time: 0 - 4: sec (0 - 29) 2sec counts 173 * time: 5 - 10: min (0 - 59) 174 * time: 11 - 15: hour (0 - 23) 175 */ 176 #define SECS_PER_MIN 60 177 #define SECS_PER_HOUR (60 * 60) 178 #define SECS_PER_DAY (SECS_PER_HOUR * 24) 179 /* days between 1.1.70 and 1.1.80 (2 leap days) */ 180 #define DAYS_DELTA (365 * 10 + 2) 181 /* 120 (2100 - 1980) isn't leap year */ 182 #define YEAR_2100 120 183 #define IS_LEAP_YEAR(y) (!((y) & 3) && (y) != YEAR_2100) 184 185 /* Linear day numbers of the respective 1sts in non-leap years. */ 186 static time_t days_in_year[] = { 187 /* Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec */ 188 0, 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 0, 0, 0, 189 }; 190 191 /* Convert a FAT time/date pair to a UNIX date (seconds since 1 1 70). */ 192 void fat_time_fat2unix(struct msdos_sb_info *sbi, struct timespec *ts, 193 __le16 __time, __le16 __date, u8 time_cs) 194 { 195 u16 time = le16_to_cpu(__time), date = le16_to_cpu(__date); 196 time_t second, day, leap_day, month, year; 197 198 year = date >> 9; 199 month = max(1, (date >> 5) & 0xf); 200 day = max(1, date & 0x1f) - 1; 201 202 leap_day = (year + 3) / 4; 203 if (year > YEAR_2100) /* 2100 isn't leap year */ 204 leap_day--; 205 if (IS_LEAP_YEAR(year) && month > 2) 206 leap_day++; 207 208 second = (time & 0x1f) << 1; 209 second += ((time >> 5) & 0x3f) * SECS_PER_MIN; 210 second += (time >> 11) * SECS_PER_HOUR; 211 second += (year * 365 + leap_day 212 + days_in_year[month] + day 213 + DAYS_DELTA) * SECS_PER_DAY; 214 215 if (!sbi->options.tz_set) 216 second += sys_tz.tz_minuteswest * SECS_PER_MIN; 217 else 218 second -= sbi->options.time_offset * SECS_PER_MIN; 219 220 if (time_cs) { 221 ts->tv_sec = second + (time_cs / 100); 222 ts->tv_nsec = (time_cs % 100) * 10000000; 223 } else { 224 ts->tv_sec = second; 225 ts->tv_nsec = 0; 226 } 227 } 228 229 /* Convert linear UNIX date to a FAT time/date pair. */ 230 void fat_time_unix2fat(struct msdos_sb_info *sbi, struct timespec *ts, 231 __le16 *time, __le16 *date, u8 *time_cs) 232 { 233 struct tm tm; 234 time_to_tm(ts->tv_sec, 235 (sbi->options.tz_set ? sbi->options.time_offset : 236 -sys_tz.tz_minuteswest) * SECS_PER_MIN, &tm); 237 238 /* FAT can only support year between 1980 to 2107 */ 239 if (tm.tm_year < 1980 - 1900) { 240 *time = 0; 241 *date = cpu_to_le16((0 << 9) | (1 << 5) | 1); 242 if (time_cs) 243 *time_cs = 0; 244 return; 245 } 246 if (tm.tm_year > 2107 - 1900) { 247 *time = cpu_to_le16((23 << 11) | (59 << 5) | 29); 248 *date = cpu_to_le16((127 << 9) | (12 << 5) | 31); 249 if (time_cs) 250 *time_cs = 199; 251 return; 252 } 253 254 /* from 1900 -> from 1980 */ 255 tm.tm_year -= 80; 256 /* 0~11 -> 1~12 */ 257 tm.tm_mon++; 258 /* 0~59 -> 0~29(2sec counts) */ 259 tm.tm_sec >>= 1; 260 261 *time = cpu_to_le16(tm.tm_hour << 11 | tm.tm_min << 5 | tm.tm_sec); 262 *date = cpu_to_le16(tm.tm_year << 9 | tm.tm_mon << 5 | tm.tm_mday); 263 if (time_cs) 264 *time_cs = (ts->tv_sec & 1) * 100 + ts->tv_nsec / 10000000; 265 } 266 EXPORT_SYMBOL_GPL(fat_time_unix2fat); 267 268 int fat_sync_bhs(struct buffer_head **bhs, int nr_bhs) 269 { 270 int i, err = 0; 271 272 for (i = 0; i < nr_bhs; i++) 273 write_dirty_buffer(bhs[i], WRITE); 274 275 for (i = 0; i < nr_bhs; i++) { 276 wait_on_buffer(bhs[i]); 277 if (!err && !buffer_uptodate(bhs[i])) 278 err = -EIO; 279 } 280 return err; 281 } 282