[linux.git] / fs / fat / misc.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 *  linux/fs/fat/misc.c
 *
 *  Written 1992,1993 by Werner Almesberger
 *  22/11/2000 - Fixed fat_date_unix2dos for dates earlier than 01/01/1980
 *		 and date_dos2unix for date==0 by Igor Zhbanov([email protected])
 */

#include "fat.h"
#include <linux/iversion.h>

/*
 * fat_fs_error reports a file system problem that might indicate fa data
 * corruption/inconsistency. Depending on 'errors' mount option the
 * panic() is called, or error message is printed FAT and nothing is done,
 * or filesystem is remounted read-only (default behavior).
 * In case the file system is remounted read-only, it can be made writable
 * again by remounting it.
 */
void __fat_fs_error(struct super_block *sb, int report, const char *fmt, ...)
{
	struct fat_mount_options *opts = &MSDOS_SB(sb)->options;
	va_list args;
	struct va_format vaf;

	if (report) {
		va_start(args, fmt);
		vaf.fmt = fmt;
		vaf.va = &args;
		fat_msg(sb, KERN_ERR, "error, %pV", &vaf);
		va_end(args);
	}

	if (opts->errors == FAT_ERRORS_PANIC)
		panic("FAT-fs (%s): fs panic from previous error\n", sb->s_id);
	else if (opts->errors == FAT_ERRORS_RO && !sb_rdonly(sb)) {
		sb->s_flags |= SB_RDONLY;
		fat_msg(sb, KERN_ERR, "Filesystem has been set read-only");
	}
}
EXPORT_SYMBOL_GPL(__fat_fs_error);

/**
 * fat_msg() - print preformated FAT specific messages. Every thing what is
 * not fat_fs_error() should be fat_msg().
 */
void fat_msg(struct super_block *sb, const char *level, const char *fmt, ...)
{
	struct va_format vaf;
	va_list args;

	va_start(args, fmt);
	vaf.fmt = fmt;
	vaf.va = &args;
	printk("%sFAT-fs (%s): %pV\n", level, sb->s_id, &vaf);
	va_end(args);
}

/* Flushes the number of free clusters on FAT32 */
/* XXX: Need to write one per FSINFO block.  Currently only writes 1 */
int fat_clusters_flush(struct super_block *sb)
{
	struct msdos_sb_info *sbi = MSDOS_SB(sb);
	struct buffer_head *bh;
	struct fat_boot_fsinfo *fsinfo;

	if (!is_fat32(sbi))
		return 0;

	bh = sb_bread(sb, sbi->fsinfo_sector);
	if (bh == NULL) {
		fat_msg(sb, KERN_ERR, "bread failed in fat_clusters_flush");
		return -EIO;
	}

	fsinfo = (struct fat_boot_fsinfo *)bh->b_data;
	/* Sanity check */
	if (!IS_FSINFO(fsinfo)) {
		fat_msg(sb, KERN_ERR, "Invalid FSINFO signature: "
		       "0x%08x, 0x%08x (sector = %lu)",
		       le32_to_cpu(fsinfo->signature1),
		       le32_to_cpu(fsinfo->signature2),
		       sbi->fsinfo_sector);
	} else {
		if (sbi->free_clusters != -1)
			fsinfo->free_clusters = cpu_to_le32(sbi->free_clusters);
		if (sbi->prev_free != -1)
			fsinfo->next_cluster = cpu_to_le32(sbi->prev_free);
		mark_buffer_dirty(bh);
	}
	brelse(bh);

	return 0;
}

/*
 * fat_chain_add() adds a new cluster to the chain of clusters represented
 * by inode.
 */
int fat_chain_add(struct inode *inode, int new_dclus, int nr_cluster)
{
	struct super_block *sb = inode->i_sb;
	struct msdos_sb_info *sbi = MSDOS_SB(sb);
	int ret, new_fclus, last;

	/*
	 * We must locate the last cluster of the file to add this new
	 * one (new_dclus) to the end of the link list (the FAT).
	 */
	last = new_fclus = 0;
	if (MSDOS_I(inode)->i_start) {
		int fclus, dclus;

		ret = fat_get_cluster(inode, FAT_ENT_EOF, &fclus, &dclus);
		if (ret < 0)
			return ret;
		new_fclus = fclus + 1;
		last = dclus;
	}

	/* add new one to the last of the cluster chain */
	if (last) {
		struct fat_entry fatent;

		fatent_init(&fatent);
		ret = fat_ent_read(inode, &fatent, last);
		if (ret >= 0) {
			int wait = inode_needs_sync(inode);
			ret = fat_ent_write(inode, &fatent, new_dclus, wait);
			fatent_brelse(&fatent);
		}
		if (ret < 0)
			return ret;
		/*
		 * FIXME:Although we can add this cache, fat_cache_add() is
		 * assuming to be called after linear search with fat_cache_id.
		 */
//		fat_cache_add(inode, new_fclus, new_dclus);
	} else {
		MSDOS_I(inode)->i_start = new_dclus;
		MSDOS_I(inode)->i_logstart = new_dclus;
		/*
		 * Since generic_write_sync() synchronizes regular files later,
		 * we sync here only directories.
		 */
		if (S_ISDIR(inode->i_mode) && IS_DIRSYNC(inode)) {
			ret = fat_sync_inode(inode);
			if (ret)
				return ret;
		} else
			mark_inode_dirty(inode);
	}
	if (new_fclus != (inode->i_blocks >> (sbi->cluster_bits - 9))) {
		fat_fs_error(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);

	return 0;
}

/*
 * 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)
/* 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 long 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,
};

static inline int fat_tz_offset(struct msdos_sb_info *sbi)
{
	return (sbi->options.tz_set ?
	       -sbi->options.time_offset :
	       sys_tz.tz_minuteswest) * SECS_PER_MIN;
}

/* 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 timespec64 *ts,
		       __le16 __time, __le16 __date, u8 time_cs)
{
	u16 time = le16_to_cpu(__time), date = le16_to_cpu(__date);
	time64_t second;
	long day, leap_day, month, year;

	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 += (time64_t)(year * 365 + leap_day
		   + days_in_year[month] + day
		   + DAYS_DELTA) * SECS_PER_DAY;

	second += fat_tz_offset(sbi);

	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 FAT time/date pair. */
void fat_time_unix2fat(struct msdos_sb_info *sbi, struct timespec64 *ts,
		       __le16 *time, __le16 *date, u8 *time_cs)
{
	struct tm tm;
	time64_to_tm(ts->tv_sec, -fat_tz_offset(sbi), &tm);

	/*  FAT can only support year between 1980 to 2107 */
	if (tm.tm_year < 1980 - 1900) {
		*time = 0;
		*date = cpu_to_le16((0 << 9) | (1 << 5) | 1);
		if (time_cs)
			*time_cs = 0;
		return;
	}
	if (tm.tm_year > 2107 - 1900) {
		*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;
	}

	/* from 1900 -> from 1980 */
	tm.tm_year -= 80;
	/* 0~11 -> 1~12 */
	tm.tm_mon++;
	/* 0~59 -> 0~29(2sec counts) */
	tm.tm_sec >>= 1;

	*time = cpu_to_le16(tm.tm_hour << 11 | tm.tm_min << 5 | tm.tm_sec);
	*date = cpu_to_le16(tm.tm_year << 9 | tm.tm_mon << 5 | tm.tm_mday);
	if (time_cs)
		*time_cs = (ts->tv_sec & 1) * 100 + ts->tv_nsec / 10000000;
}
EXPORT_SYMBOL_GPL(fat_time_unix2fat);

static inline struct timespec64 fat_timespec64_trunc_2secs(struct timespec64 ts)
{
	return (struct timespec64){ ts.tv_sec & ~1ULL, 0 };
}

static inline struct timespec64 fat_timespec64_trunc_10ms(struct timespec64 ts)
{
	if (ts.tv_nsec)
		ts.tv_nsec -= ts.tv_nsec % 10000000UL;
	return ts;
}

/*
 * truncate the various times with appropriate granularity:
 *   root inode:
 *     all times always 0
 *   all other inodes:
 *     mtime - 2 seconds
 *     ctime
 *       msdos - 2 seconds
 *       vfat  - 10 milliseconds
 *     atime - 24 hours (00:00:00 in local timezone)
 */
int fat_truncate_time(struct inode *inode, struct timespec64 *now, int flags)
{
	struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
	struct timespec64 ts;

	if (inode->i_ino == MSDOS_ROOT_INO)
		return 0;

	if (now == NULL) {
		now = &ts;
		ts = current_time(inode);
	}

	if (flags & S_ATIME) {
		/* to localtime */
		time64_t seconds = now->tv_sec - fat_tz_offset(sbi);
		s32 remainder;

		div_s64_rem(seconds, SECS_PER_DAY, &remainder);
		/* to day boundary, and back to unix time */
		seconds = seconds + fat_tz_offset(sbi) - remainder;

		inode->i_atime = (struct timespec64){ seconds, 0 };
	}
	if (flags & S_CTIME) {
		if (sbi->options.isvfat)
			inode->i_ctime = fat_timespec64_trunc_10ms(*now);
		else
			inode->i_ctime = fat_timespec64_trunc_2secs(*now);
	}
	if (flags & S_MTIME)
		inode->i_mtime = fat_timespec64_trunc_2secs(*now);

	return 0;
}
EXPORT_SYMBOL_GPL(fat_truncate_time);

int fat_update_time(struct inode *inode, struct timespec64 *now, int flags)
{
	int iflags = I_DIRTY_TIME;
	bool dirty = false;

	if (inode->i_ino == MSDOS_ROOT_INO)
		return 0;

	fat_truncate_time(inode, now, flags);
	if (flags & S_VERSION)
		dirty = inode_maybe_inc_iversion(inode, false);
	if ((flags & (S_ATIME | S_CTIME | S_MTIME)) &&
	    !(inode->i_sb->s_flags & SB_LAZYTIME))
		dirty = true;

	if (dirty)
		iflags |= I_DIRTY_SYNC;
	__mark_inode_dirty(inode, iflags);
	return 0;
}
EXPORT_SYMBOL_GPL(fat_update_time);

int fat_sync_bhs(struct buffer_head **bhs, int nr_bhs)
{
	int i, err = 0;

	for (i = 0; i < nr_bhs; i++)
		write_dirty_buffer(bhs[i], 0);

	for (i = 0; i < nr_bhs; i++) {
		wait_on_buffer(bhs[i]);
		if (!err && !buffer_uptodate(bhs[i]))
			err = -EIO;
	}
	return err;
}
Commit	Line	Data
457c8996	1	// SPDX-License-Identifier: GPL-2.0-only
1da177e4 LT	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([email protected])
	8	*/
	9
9e975dae	10	#include "fat.h"
6bb885ec	11	#include <linux/iversion.h>
1da177e4 LT	12
1da177e4 LT	13	/*
85c78591 DK	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.
1da177e4	20	*/
2c8a5ffb	21	void __fat_fs_error(struct super_block sb, int report, const char fmt, ...)
1da177e4	22	{
2c8a5ffb	23	struct fat_mount_options *opts = &MSDOS_SB(sb)->options;
1da177e4	24	va_list args;
2c8a5ffb	25	struct va_format vaf;
1da177e4	26
aaa04b48	27	if (report) {
aaa04b48	28	va_start(args, fmt);
2c8a5ffb OR	29	vaf.fmt = fmt;
2c8a5ffb OR	30	vaf.va = &args;
e68e96d2	31	fat_msg(sb, KERN_ERR, "error, %pV", &vaf);
aaa04b48	32	va_end(args);
aaa04b48	33	}
1da177e4	34
85c78591	35	if (opts->errors == FAT_ERRORS_PANIC)
2c8a5ffb	36	panic("FAT-fs (%s): fs panic from previous error\n", sb->s_id);
bc98a42c	37	else if (opts->errors == FAT_ERRORS_RO && !sb_rdonly(sb)) {
1751e8a6	38	sb->s_flags \|= SB_RDONLY;
e68e96d2	39	fat_msg(sb, KERN_ERR, "Filesystem has been set read-only");
1da177e4 LT	40	}
1da177e4 LT	41	}
aaa04b48	42	EXPORT_SYMBOL_GPL(__fat_fs_error);
1da177e4	43
81ac21d3 OR	44	/**
	45	* fat_msg() - print preformated FAT specific messages. Every thing what is
	46	* not fat_fs_error() should be fat_msg().
	47	*/
	48	void 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
1da177e4 LT	60	/* Flushes the number of free clusters on FAT32 */
1da177e4 LT	61	/* XXX: Need to write one per FSINFO block. Currently only writes 1 */
ed248b29	62	int fat_clusters_flush(struct super_block *sb)
1da177e4 LT	63	{
	64	struct msdos_sb_info *sbi = MSDOS_SB(sb);
	65	struct buffer_head *bh;
	66	struct fat_boot_fsinfo *fsinfo;
	67
306790f7	68	if (!is_fat32(sbi))
ed248b29	69	return 0;
1da177e4 LT	70
	71	bh = sb_bread(sb, sbi->fsinfo_sector);
	72	if (bh == NULL) {
869f58c0	73	fat_msg(sb, KERN_ERR, "bread failed in fat_clusters_flush");
ed248b29	74	return -EIO;
1da177e4 LT	75	}
	76
	77	fsinfo = (struct fat_boot_fsinfo *)bh->b_data;
	78	/* Sanity check */
	79	if (!IS_FSINFO(fsinfo)) {
869f58c0 OR	80	fat_msg(sb, KERN_ERR, "Invalid FSINFO signature: "
869f58c0 OR	81	"0x%08x, 0x%08x (sector = %lu)",
1da177e4 LT	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);
1da177e4 LT	91	}
1da177e4 LT	92	brelse(bh);
ed248b29 OH	93
ed248b29 OH	94	return 0;
1da177e4 LT	95	}
	96
	97	/*
	98	* fat_chain_add() adds a new cluster to the chain of clusters represented
	99	* by inode.
	100	*/
	101	int 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;
c39540c6 R	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	*/
1da177e4 LT	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	/*
2f3d675b JK	144	* Since generic_write_sync() synchronizes regular files later,
2f3d675b JK	145	* we sync here only directories.
1da177e4 LT	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))) {
85c78591	155	fat_fs_error(sb, "clusters badly computed (%d != %llu)",
c3302931 OH	156	new_fclus,
c3302931 OH	157	(llu)(inode->i_blocks >> (sbi->cluster_bits - 9)));
1da177e4 LT	158	fat_cache_inval_inode(inode);
	159	}
	160	inode->i_blocks += nr_cluster << (sbi->cluster_bits - 9);
	161
	162	return 0;
	163	}
	164
7decd1cb OH	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)
7decd1cb OH	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
1da177e4	184	/* Linear day numbers of the respective 1sts in non-leap years. */
f423420c	185	static long days_in_year[] = {
7decd1cb OH	186	/* Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec */
7decd1cb OH	187	0, 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 0, 0, 0,
1da177e4 LT	188	};
1da177e4 LT	189
d9f4d942 FS	190	static 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
7decd1cb	197	/* Convert a FAT time/date pair to a UNIX date (seconds since 1 1 70). */
f423420c	198	void fat_time_fat2unix(struct msdos_sb_info sbi, struct timespec64 ts,
7decd1cb	199	__le16 __time, __le16 __date, u8 time_cs)
1da177e4	200	{
7decd1cb	201	u16 time = le16_to_cpu(__time), date = le16_to_cpu(__date);
f423420c AB	202	time64_t second;
f423420c AB	203	long day, leap_day, month, year;
1da177e4	204
7decd1cb OH	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;
f423420c	218	second += (time64_t)(year * 365 + leap_day
7decd1cb OH	219	+ days_in_year[month] + day
	220	+ DAYS_DELTA) * SECS_PER_DAY;
	221
d9f4d942	222	second += fat_tz_offset(sbi);
7decd1cb OH	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	}
1da177e4 LT	231	}
1da177e4 LT	232
7decd1cb	233	/* Convert linear UNIX date to a FAT time/date pair. */
f423420c	234	void fat_time_unix2fat(struct msdos_sb_info sbi, struct timespec64 ts,
7decd1cb	235	__le16 time, __le16 date, u8 *time_cs)
1da177e4	236	{
1d81a181	237	struct tm tm;
d9f4d942	238	time64_to_tm(ts->tv_sec, -fat_tz_offset(sbi), &tm);
1da177e4	239
1d81a181 Z	240	/* FAT can only support year between 1980 to 2107 */
1d81a181 Z	241	if (tm.tm_year < 1980 - 1900) {
7decd1cb OH	242	*time = 0;
	243	*date = cpu_to_le16((0 << 9) \| (1 << 5) \| 1);
	244	if (time_cs)
	245	*time_cs = 0;
	246	return;
	247	}
1d81a181	248	if (tm.tm_year > 2107 - 1900) {
7decd1cb OH	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	}
7decd1cb	255
1d81a181 Z	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;
1da177e4	262
1d81a181 Z	263	*time = cpu_to_le16(tm.tm_hour << 11 \| tm.tm_min << 5 \| tm.tm_sec);
1d81a181 Z	264	*date = cpu_to_le16(tm.tm_year << 9 \| tm.tm_mon << 5 \| tm.tm_mday);
7decd1cb OH	265	if (time_cs)
	266	time_cs = (ts->tv_sec & 1) 100 + ts->tv_nsec / 10000000;
	267	}
	268	EXPORT_SYMBOL_GPL(fat_time_unix2fat);
1da177e4	269
6bb885ec FS	270	static inline struct timespec64 fat_timespec64_trunc_2secs(struct timespec64 ts)
	271	{
	272	return (struct timespec64){ ts.tv_sec & ~1ULL, 0 };
	273	}
97acf83d DD	274
	275	static 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
6bb885ec FS	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	*/
	293	int 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)
97acf83d	319	inode->i_ctime = fat_timespec64_trunc_10ms(*now);
6bb885ec FS	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	}
	328	EXPORT_SYMBOL_GPL(fat_truncate_time);
	329
	330	int 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	}
	350	EXPORT_SYMBOL_GPL(fat_update_time);
	351
1da177e4 LT	352	int fat_sync_bhs(struct buffer_head **bhs, int nr_bhs)
1da177e4 LT	353	{
5b00226d	354	int i, err = 0;
1da177e4	355
9cb569d6	356	for (i = 0; i < nr_bhs; i++)
2a222ca9	357	write_dirty_buffer(bhs[i], 0);
9cb569d6	358
1da177e4 LT	359	for (i = 0; i < nr_bhs; i++) {
1da177e4 LT	360	wait_on_buffer(bhs[i]);
0edd55fa	361	if (!err && !buffer_uptodate(bhs[i]))
1da177e4 LT	362	err = -EIO;
	363	}
	364	return err;
	365	}