fat: convert to ctime accessor functions

In later patches, we're going to change how the inode's ctime field is
used. Switch to using accessor functions instead of raw accesses of
inode->i_ctime.
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Message-Id: <20230705190309.579783-42-jlayton@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>

fs/fat/inode.c

@@ -562,7 +562,7 @@ int fat_fill_inode(struct inode *inode, struct msdos_dir_entry *de)
 			   & ~((loff_t)sbi->cluster_size - 1)) >> 9;
 
 	fat_time_fat2unix(sbi, &inode->i_mtime, de->time, de->date, 0);
-	inode->i_ctime = inode->i_mtime;
+	inode_set_ctime_to_ts(inode, inode->i_mtime);
 	if (sbi->options.isvfat) {
 		fat_time_fat2unix(sbi, &inode->i_atime, 0, de->adate, 0);
 		fat_time_fat2unix(sbi, &MSDOS_I(inode)->i_crtime, de->ctime,
@@ -1407,8 +1407,7 @@ static int fat_read_root(struct inode *inode)
 	MSDOS_I(inode)->mmu_private = inode->i_size;
 
 	fat_save_attrs(inode, ATTR_DIR);
-	inode->i_mtime.tv_sec = inode->i_atime.tv_sec = inode->i_ctime.tv_sec = 0;
-	inode->i_mtime.tv_nsec = inode->i_atime.tv_nsec = inode->i_ctime.tv_nsec = 0;
+	inode->i_mtime = inode->i_atime = inode_set_ctime(inode, 0, 0);
 	set_nlink(inode, fat_subdirs(inode)+2);
 
 	return 0;

fs/fat/misc.c

@@ -332,7 +332,8 @@ int fat_truncate_time(struct inode *inode, struct timespec64 *now, int flags)
 	 * but ctime updates are ignored.
 	 */
 	if (flags & S_MTIME)
-		inode->i_mtime = inode->i_ctime = fat_truncate_mtime(sbi, now);
+		inode->i_mtime = inode_set_ctime_to_ts(inode,
+						       fat_truncate_mtime(sbi, now));
 
 	return 0;
 }