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-rw-r--r--fs/fat/misc.c155
1 files changed, 111 insertions, 44 deletions
diff --git a/fs/fat/misc.c b/fs/fat/misc.c
index 79fb98ad36d4..ac39ebcc1496 100644
--- a/fs/fat/misc.c
+++ b/fs/fat/misc.c
@@ -8,8 +8,8 @@
#include <linux/module.h>
#include <linux/fs.h>
-#include <linux/msdos_fs.h>
#include <linux/buffer_head.h>
+#include "fat.h"
/*
* fat_fs_panic reports a severe file system problem and sets the file system
@@ -124,8 +124,9 @@ int fat_chain_add(struct inode *inode, int new_dclus, int nr_cluster)
mark_inode_dirty(inode);
}
if (new_fclus != (inode->i_blocks >> (sbi->cluster_bits - 9))) {
- fat_fs_panic(sb, "clusters badly computed (%d != %lu)",
- new_fclus, inode->i_blocks >> (sbi->cluster_bits - 9));
+ fat_fs_panic(sb, "clusters badly computed (%d != %llu)",
+ new_fclus,
+ (llu)(inode->i_blocks >> (sbi->cluster_bits - 9)));
fat_cache_inval_inode(inode);
}
inode->i_blocks += nr_cluster << (sbi->cluster_bits - 9);
@@ -135,65 +136,131 @@ int fat_chain_add(struct inode *inode, int new_dclus, int nr_cluster)
extern struct timezone sys_tz;
+/*
+ * The epoch of FAT timestamp is 1980.
+ * : bits : value
+ * date: 0 - 4: day (1 - 31)
+ * date: 5 - 8: month (1 - 12)
+ * date: 9 - 15: year (0 - 127) from 1980
+ * time: 0 - 4: sec (0 - 29) 2sec counts
+ * time: 5 - 10: min (0 - 59)
+ * time: 11 - 15: hour (0 - 23)
+ */
+#define SECS_PER_MIN 60
+#define SECS_PER_HOUR (60 * 60)
+#define SECS_PER_DAY (SECS_PER_HOUR * 24)
+#define UNIX_SECS_1980 315532800L
+#if BITS_PER_LONG == 64
+#define UNIX_SECS_2108 4354819200L
+#endif
+/* days between 1.1.70 and 1.1.80 (2 leap days) */
+#define DAYS_DELTA (365 * 10 + 2)
+/* 120 (2100 - 1980) isn't leap year */
+#define YEAR_2100 120
+#define IS_LEAP_YEAR(y) (!((y) & 3) && (y) != YEAR_2100)
+
/* Linear day numbers of the respective 1sts in non-leap years. */
-static int day_n[] = {
- /* Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec */
- 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 0, 0, 0, 0
+static time_t days_in_year[] = {
+ /* Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec */
+ 0, 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 0, 0, 0,
};
-/* Convert a MS-DOS time/date pair to a UNIX date (seconds since 1 1 70). */
-int date_dos2unix(unsigned short time, unsigned short date, int tz_utc)
+/* Convert a FAT time/date pair to a UNIX date (seconds since 1 1 70). */
+void fat_time_fat2unix(struct msdos_sb_info *sbi, struct timespec *ts,
+ __le16 __time, __le16 __date, u8 time_cs)
{
- int month, year, secs;
+ u16 time = le16_to_cpu(__time), date = le16_to_cpu(__date);
+ time_t second, day, leap_day, month, year;
- /*
- * first subtract and mask after that... Otherwise, if
- * date == 0, bad things happen
- */
- month = ((date >> 5) - 1) & 15;
- year = date >> 9;
- secs = (time & 31)*2+60*((time >> 5) & 63)+(time >> 11)*3600+86400*
- ((date & 31)-1+day_n[month]+(year/4)+year*365-((year & 3) == 0 &&
- month < 2 ? 1 : 0)+3653);
- /* days since 1.1.70 plus 80's leap day */
- if (!tz_utc)
- secs += sys_tz.tz_minuteswest*60;
- return secs;
+ year = date >> 9;
+ month = max(1, (date >> 5) & 0xf);
+ day = max(1, date & 0x1f) - 1;
+
+ leap_day = (year + 3) / 4;
+ if (year > YEAR_2100) /* 2100 isn't leap year */
+ leap_day--;
+ if (IS_LEAP_YEAR(year) && month > 2)
+ leap_day++;
+
+ second = (time & 0x1f) << 1;
+ second += ((time >> 5) & 0x3f) * SECS_PER_MIN;
+ second += (time >> 11) * SECS_PER_HOUR;
+ second += (year * 365 + leap_day
+ + days_in_year[month] + day
+ + DAYS_DELTA) * SECS_PER_DAY;
+
+ if (!sbi->options.tz_utc)
+ second += sys_tz.tz_minuteswest * SECS_PER_MIN;
+
+ if (time_cs) {
+ ts->tv_sec = second + (time_cs / 100);
+ ts->tv_nsec = (time_cs % 100) * 10000000;
+ } else {
+ ts->tv_sec = second;
+ ts->tv_nsec = 0;
+ }
}
-/* Convert linear UNIX date to a MS-DOS time/date pair. */
-void fat_date_unix2dos(int unix_date, __le16 *time, __le16 *date, int tz_utc)
+/* Convert linear UNIX date to a FAT time/date pair. */
+void fat_time_unix2fat(struct msdos_sb_info *sbi, struct timespec *ts,
+ __le16 *time, __le16 *date, u8 *time_cs)
{
- int day, year, nl_day, month;
+ time_t second = ts->tv_sec;
+ time_t day, leap_day, month, year;
- if (!tz_utc)
- unix_date -= sys_tz.tz_minuteswest*60;
+ if (!sbi->options.tz_utc)
+ second -= sys_tz.tz_minuteswest * SECS_PER_MIN;
/* Jan 1 GMT 00:00:00 1980. But what about another time zone? */
- if (unix_date < 315532800)
- unix_date = 315532800;
-
- *time = cpu_to_le16((unix_date % 60)/2+(((unix_date/60) % 60) << 5)+
- (((unix_date/3600) % 24) << 11));
- day = unix_date/86400-3652;
- year = day/365;
- if ((year+3)/4+365*year > day)
+ if (second < UNIX_SECS_1980) {
+ *time = 0;
+ *date = cpu_to_le16((0 << 9) | (1 << 5) | 1);
+ if (time_cs)
+ *time_cs = 0;
+ return;
+ }
+#if BITS_PER_LONG == 64
+ if (second >= UNIX_SECS_2108) {
+ *time = cpu_to_le16((23 << 11) | (59 << 5) | 29);
+ *date = cpu_to_le16((127 << 9) | (12 << 5) | 31);
+ if (time_cs)
+ *time_cs = 199;
+ return;
+ }
+#endif
+
+ day = second / SECS_PER_DAY - DAYS_DELTA;
+ year = day / 365;
+ leap_day = (year + 3) / 4;
+ if (year > YEAR_2100) /* 2100 isn't leap year */
+ leap_day--;
+ if (year * 365 + leap_day > day)
year--;
- day -= (year+3)/4+365*year;
- if (day == 59 && !(year & 3)) {
- nl_day = day;
+ leap_day = (year + 3) / 4;
+ if (year > YEAR_2100) /* 2100 isn't leap year */
+ leap_day--;
+ day -= year * 365 + leap_day;
+
+ if (IS_LEAP_YEAR(year) && day == days_in_year[3]) {
month = 2;
} else {
- nl_day = (year & 3) || day <= 59 ? day : day-1;
- for (month = 0; month < 12; month++) {
- if (day_n[month] > nl_day)
+ if (IS_LEAP_YEAR(year) && day > days_in_year[3])
+ day--;
+ for (month = 1; month < 12; month++) {
+ if (days_in_year[month + 1] > day)
break;
}
}
- *date = cpu_to_le16(nl_day-day_n[month-1]+1+(month << 5)+(year << 9));
-}
+ day -= days_in_year[month];
-EXPORT_SYMBOL_GPL(fat_date_unix2dos);
+ *time = cpu_to_le16(((second / SECS_PER_HOUR) % 24) << 11
+ | ((second / SECS_PER_MIN) % 60) << 5
+ | (second % SECS_PER_MIN) >> 1);
+ *date = cpu_to_le16((year << 9) | (month << 5) | (day + 1));
+ if (time_cs)
+ *time_cs = (ts->tv_sec & 1) * 100 + ts->tv_nsec / 10000000;
+}
+EXPORT_SYMBOL_GPL(fat_time_unix2fat);
int fat_sync_bhs(struct buffer_head **bhs, int nr_bhs)
{
generated by cgit v1.2.3 (git 2.25.1) at 2024-12-26 19:13:59 +0000