1 files changed, 120 insertions, 29 deletions

diff --git a/fs/fat/misc.c b/fs/fat/misc.c
index 628e22a5a543..950da09f0961 100644
--- a/fs/fat/misc.c
+++ b/fs/fat/misc.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  *  linux/fs/fat/misc.c
  *
@@ -6,11 +7,8 @@
  *		 and date_dos2unix for date==0 by Igor Zhbanov(bsg@uniyar.ac.ru)
  */
 
-#include <linux/module.h>
-#include <linux/fs.h>
-#include <linux/buffer_head.h>
-#include <linux/time.h>
 #include "fat.h"
+#include <linux/iversion.h>
 
 /*
  * fat_fs_error reports a file system problem that might indicate fa data
@@ -36,18 +34,24 @@ void __fat_fs_error(struct super_block *sb, int report, const char *fmt, ...)
 
 	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->s_flags & MS_RDONLY)) {
-		sb->s_flags |= MS_RDONLY;
+	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().
+ * _fat_msg() - Print a preformatted FAT message based on a superblock.
+ * @sb: A pointer to a &struct super_block
+ * @level: A Kernel printk level constant
+ * @fmt: The printf-style format string to print.
+ *
+ * Everything that is not fat_fs_error() should be fat_msg().
+ *
+ * fat_msg() wraps _fat_msg() for printk indexing.
  */
-void fat_msg(struct super_block *sb, const char *level, const char *fmt, ...)
+void _fat_msg(struct super_block *sb, const char *level, const char *fmt, ...)
 {
 	struct va_format vaf;
 	va_list args;
@@ -55,7 +59,7 @@ void fat_msg(struct super_block *sb, const char *level, const char *fmt, ...)
 	va_start(args, fmt);
 	vaf.fmt = fmt;
 	vaf.va = &args;
-	printk("%sFAT-fs (%s): %pV\n", level, sb->s_id, &vaf);
+	_printk(FAT_PRINTK_PREFIX "%pV\n", level, sb->s_id, &vaf);
 	va_end(args);
 }
 
@@ -67,7 +71,7 @@ int fat_clusters_flush(struct super_block *sb)
 	struct buffer_head *bh;
 	struct fat_boot_fsinfo *fsinfo;
 
-	if (sbi->fat_bits != 32)
+	if (!is_fat32(sbi))
 		return 0;
 
 	bh = sb_bread(sb, sbi->fsinfo_sector);
@@ -154,9 +158,9 @@ 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_error(sb, "clusters badly computed (%d != %llu)",
-			     new_fclus,
-			     (llu)(inode->i_blocks >> (sbi->cluster_bits - 9)));
+		fat_fs_error_ratelimit(
+			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);
@@ -164,8 +168,6 @@ int fat_chain_add(struct inode *inode, int new_dclus, int nr_cluster)
 	return 0;
 }
 
-extern struct timezone sys_tz;
-
 /*
  * The epoch of FAT timestamp is 1980.
  *     :  bits :     value
@@ -186,17 +188,25 @@ extern struct timezone sys_tz;
 #define IS_LEAP_YEAR(y)	(!((y) & 3) && (y) != YEAR_2100)
 
 /* Linear day numbers of the respective 1sts in non-leap years. */
-static time_t days_in_year[] = {
+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(const 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 timespec *ts,
+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);
-	time_t second, day, leap_day, month, year;
+	time64_t second;
+	long day, leap_day, month, year;
 
 	year  = date >> 9;
 	month = max(1, (date >> 5) & 0xf);
@@ -211,14 +221,11 @@ void fat_time_fat2unix(struct msdos_sb_info *sbi, struct timespec *ts,
 	second =  (time & 0x1f) << 1;
 	second += ((time >> 5) & 0x3f) * SECS_PER_MIN;
 	second += (time >> 11) * SECS_PER_HOUR;
-	second += (year * 365 + leap_day
+	second += (time64_t)(year * 365 + leap_day
 		   + days_in_year[month] + day
 		   + DAYS_DELTA) * SECS_PER_DAY;
 
-	if (!sbi->options.tz_set)
-		second += sys_tz.tz_minuteswest * SECS_PER_MIN;
-	else
-		second -= sbi->options.time_offset * SECS_PER_MIN;
+	second += fat_tz_offset(sbi);
 
 	if (time_cs) {
 		ts->tv_sec = second + (time_cs / 100);
@@ -229,14 +236,15 @@ void fat_time_fat2unix(struct msdos_sb_info *sbi, struct timespec *ts,
 	}
 }
 
+/* Export fat_time_fat2unix() for the fat_test KUnit tests. */
+EXPORT_SYMBOL_GPL(fat_time_fat2unix);
+
 /* Convert linear UNIX date to a FAT time/date pair. */
-void fat_time_unix2fat(struct msdos_sb_info *sbi, struct timespec *ts,
+void fat_time_unix2fat(struct msdos_sb_info *sbi, struct timespec64 *ts,
 		       __le16 *time, __le16 *date, u8 *time_cs)
 {
 	struct tm tm;
-	time_to_tm(ts->tv_sec,
-		   (sbi->options.tz_set ? sbi->options.time_offset :
-		   -sys_tz.tz_minuteswest) * SECS_PER_MIN, &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) {
@@ -268,12 +276,95 @@ void fat_time_unix2fat(struct msdos_sb_info *sbi, struct timespec *ts,
 }
 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 };
+}
+
+/*
+ * truncate atime to 24 hour granularity (00:00:00 in local timezone)
+ */
+struct timespec64 fat_truncate_atime(const struct msdos_sb_info *sbi,
+				     const struct timespec64 *ts)
+{
+	/* to localtime */
+	time64_t seconds = ts->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;
+
+	return (struct timespec64){ seconds, 0 };
+}
+
+/*
+ * truncate mtime to 2 second granularity
+ */
+struct timespec64 fat_truncate_mtime(const struct msdos_sb_info *sbi,
+				     const struct timespec64 *ts)
+{
+	return fat_timespec64_trunc_2secs(*ts);
+}
+
+/*
+ * truncate the various times with appropriate granularity:
+ *   all times in root node are always 0
+ */
+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)
+		inode_set_atime_to_ts(inode, fat_truncate_atime(sbi, now));
+	/*
+	 * ctime and mtime share the same on-disk field, and should be
+	 * identical in memory. all mtime updates will be applied to ctime,
+	 * but ctime updates are ignored.
+	 */
+	if (flags & S_MTIME)
+		inode_set_mtime_to_ts(inode,
+				      inode_set_ctime_to_ts(inode, fat_truncate_mtime(sbi, now)));
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(fat_truncate_time);
+
+int fat_update_time(struct inode *inode, int flags)
+{
+	int dirty_flags = 0;
+
+	if (inode->i_ino == MSDOS_ROOT_INO)
+		return 0;
+
+	if (flags & (S_ATIME | S_CTIME | S_MTIME)) {
+		fat_truncate_time(inode, NULL, flags);
+		if (inode->i_sb->s_flags & SB_LAZYTIME)
+			dirty_flags |= I_DIRTY_TIME;
+		else
+			dirty_flags |= I_DIRTY_SYNC;
+	}
+
+	__mark_inode_dirty(inode, dirty_flags);
+	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], WRITE);
+		write_dirty_buffer(bhs[i], 0);
 
 	for (i = 0; i < nr_bhs; i++) {
 		wait_on_buffer(bhs[i]);