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)
9 #include <linux/module.h>
11 #include <linux/buffer_head.h>
15 * fat_fs_panic reports a severe file system problem and sets the file system
16 * read-only. The file system can be made writable again by remounting it.
18 void fat_fs_panic(struct super_block *s, const char *fmt, ...)
22 printk(KERN_ERR "FAT: Filesystem panic (dev %s)\n", s->s_id);
30 if (!(s->s_flags & MS_RDONLY)) {
31 s->s_flags |= MS_RDONLY;
32 printk(KERN_ERR " File system has been set read-only\n");
36 EXPORT_SYMBOL_GPL(fat_fs_panic);
38 /* Flushes the number of free clusters on FAT32 */
39 /* XXX: Need to write one per FSINFO block. Currently only writes 1 */
40 void fat_clusters_flush(struct super_block *sb)
42 struct msdos_sb_info *sbi = MSDOS_SB(sb);
43 struct buffer_head *bh;
44 struct fat_boot_fsinfo *fsinfo;
46 if (sbi->fat_bits != 32)
49 bh = sb_bread(sb, sbi->fsinfo_sector);
51 printk(KERN_ERR "FAT: bread failed in fat_clusters_flush\n");
55 fsinfo = (struct fat_boot_fsinfo *)bh->b_data;
57 if (!IS_FSINFO(fsinfo)) {
58 printk(KERN_ERR "FAT: Invalid FSINFO signature: "
59 "0x%08x, 0x%08x (sector = %lu)\n",
60 le32_to_cpu(fsinfo->signature1),
61 le32_to_cpu(fsinfo->signature2),
64 if (sbi->free_clusters != -1)
65 fsinfo->free_clusters = cpu_to_le32(sbi->free_clusters);
66 if (sbi->prev_free != -1)
67 fsinfo->next_cluster = cpu_to_le32(sbi->prev_free);
68 mark_buffer_dirty(bh);
74 * fat_chain_add() adds a new cluster to the chain of clusters represented
77 int fat_chain_add(struct inode *inode, int new_dclus, int nr_cluster)
79 struct super_block *sb = inode->i_sb;
80 struct msdos_sb_info *sbi = MSDOS_SB(sb);
81 int ret, new_fclus, last;
84 * We must locate the last cluster of the file to add this new
85 * one (new_dclus) to the end of the link list (the FAT).
88 if (MSDOS_I(inode)->i_start) {
91 ret = fat_get_cluster(inode, FAT_ENT_EOF, &fclus, &dclus);
94 new_fclus = fclus + 1;
98 /* add new one to the last of the cluster chain */
100 struct fat_entry fatent;
102 fatent_init(&fatent);
103 ret = fat_ent_read(inode, &fatent, last);
105 int wait = inode_needs_sync(inode);
106 ret = fat_ent_write(inode, &fatent, new_dclus, wait);
107 fatent_brelse(&fatent);
111 // fat_cache_add(inode, new_fclus, new_dclus);
113 MSDOS_I(inode)->i_start = new_dclus;
114 MSDOS_I(inode)->i_logstart = new_dclus;
116 * Since generic_osync_inode() synchronize later if
117 * this is not directory, we don't here.
119 if (S_ISDIR(inode->i_mode) && IS_DIRSYNC(inode)) {
120 ret = fat_sync_inode(inode);
124 mark_inode_dirty(inode);
126 if (new_fclus != (inode->i_blocks >> (sbi->cluster_bits - 9))) {
127 fat_fs_panic(sb, "clusters badly computed (%d != %lu)",
128 new_fclus, inode->i_blocks >> (sbi->cluster_bits - 9));
129 fat_cache_inval_inode(inode);
131 inode->i_blocks += nr_cluster << (sbi->cluster_bits - 9);
136 extern struct timezone sys_tz;
139 * The epoch of FAT timestamp is 1980.
141 * date: 0 - 4: day (1 - 31)
142 * date: 5 - 8: month (1 - 12)
143 * date: 9 - 15: year (0 - 127) from 1980
144 * time: 0 - 4: sec (0 - 29) 2sec counts
145 * time: 5 - 10: min (0 - 59)
146 * time: 11 - 15: hour (0 - 23)
148 #define SECS_PER_MIN 60
149 #define SECS_PER_HOUR (60 * 60)
150 #define SECS_PER_DAY (SECS_PER_HOUR * 24)
151 #define UNIX_SECS_1980 315532800L
152 #if BITS_PER_LONG == 64
153 #define UNIX_SECS_2108 4354819200L
155 /* days between 1.1.70 and 1.1.80 (2 leap days) */
156 #define DAYS_DELTA (365 * 10 + 2)
157 /* 120 (2100 - 1980) isn't leap year */
158 #define YEAR_2100 120
159 #define IS_LEAP_YEAR(y) (!((y) & 3) && (y) != YEAR_2100)
161 /* Linear day numbers of the respective 1sts in non-leap years. */
162 static time_t days_in_year[] = {
163 /* Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec */
164 0, 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 0, 0, 0,
167 /* Convert a FAT time/date pair to a UNIX date (seconds since 1 1 70). */
168 void fat_time_fat2unix(struct msdos_sb_info *sbi, struct timespec *ts,
169 __le16 __time, __le16 __date, u8 time_cs)
171 u16 time = le16_to_cpu(__time), date = le16_to_cpu(__date);
172 time_t second, day, leap_day, month, year;
175 month = max(1, (date >> 5) & 0xf);
176 day = max(1, date & 0x1f) - 1;
178 leap_day = (year + 3) / 4;
179 if (year > YEAR_2100) /* 2100 isn't leap year */
181 if (IS_LEAP_YEAR(year) && month > 2)
184 second = (time & 0x1f) << 1;
185 second += ((time >> 5) & 0x3f) * SECS_PER_MIN;
186 second += (time >> 11) * SECS_PER_HOUR;
187 second += (year * 365 + leap_day
188 + days_in_year[month] + day
189 + DAYS_DELTA) * SECS_PER_DAY;
191 if (!sbi->options.tz_utc)
192 second += sys_tz.tz_minuteswest * SECS_PER_MIN;
195 ts->tv_sec = second + (time_cs / 100);
196 ts->tv_nsec = (time_cs % 100) * 10000000;
203 /* Convert linear UNIX date to a FAT time/date pair. */
204 void fat_time_unix2fat(struct msdos_sb_info *sbi, struct timespec *ts,
205 __le16 *time, __le16 *date, u8 *time_cs)
207 time_t second = ts->tv_sec;
208 time_t day, leap_day, month, year;
210 if (!sbi->options.tz_utc)
211 second -= sys_tz.tz_minuteswest * SECS_PER_MIN;
213 /* Jan 1 GMT 00:00:00 1980. But what about another time zone? */
214 if (second < UNIX_SECS_1980) {
216 *date = cpu_to_le16((0 << 9) | (1 << 5) | 1);
221 #if BITS_PER_LONG == 64
222 if (second >= UNIX_SECS_2108) {
223 *time = cpu_to_le16((23 << 11) | (59 << 5) | 29);
224 *date = cpu_to_le16((127 << 9) | (12 << 5) | 31);
231 day = second / SECS_PER_DAY - DAYS_DELTA;
233 leap_day = (year + 3) / 4;
234 if (year > YEAR_2100) /* 2100 isn't leap year */
236 if (year * 365 + leap_day > day)
238 leap_day = (year + 3) / 4;
239 if (year > YEAR_2100) /* 2100 isn't leap year */
241 day -= year * 365 + leap_day;
243 if (IS_LEAP_YEAR(year) && day == days_in_year[3]) {
246 if (IS_LEAP_YEAR(year) && day > days_in_year[3])
248 for (month = 1; month < 12; month++) {
249 if (days_in_year[month + 1] > day)
253 day -= days_in_year[month];
255 *time = cpu_to_le16(((second / SECS_PER_HOUR) % 24) << 11
256 | ((second / SECS_PER_MIN) % 60) << 5
257 | (second % SECS_PER_MIN) >> 1);
258 *date = cpu_to_le16((year << 9) | (month << 5) | (day + 1));
260 *time_cs = (ts->tv_sec & 1) * 100 + ts->tv_nsec / 10000000;
262 EXPORT_SYMBOL_GPL(fat_time_unix2fat);
264 int fat_sync_bhs(struct buffer_head **bhs, int nr_bhs)
268 ll_rw_block(SWRITE, nr_bhs, bhs);
269 for (i = 0; i < nr_bhs; i++) {
270 wait_on_buffer(bhs[i]);
271 if (buffer_eopnotsupp(bhs[i])) {
272 clear_buffer_eopnotsupp(bhs[i]);
274 } else if (!err && !buffer_uptodate(bhs[i]))