From 81df1ad40644b706a1cdbd28a1471f9f0c0ea3e8 Mon Sep 17 00:00:00 2001

From: Eric Sandeen <sandeen@sandeen.net>

Date: Tue, 21 Apr 2020 11:13:10 +0900

Subject: [Backport 81df1ad40644] exfat: truncate atimes to 2s granularity

The timestamp for access_time has double seconds granularity(There is no

10msIncrement field for access_time unlike create/modify_time).

exfat's atimes are restricted to only 2s granularity so after

we set an atime, round it down to the nearest 2s and set the

sub-second component of the timestamp to 0.

Signed-off-by: Eric Sandeen <sandeen@sandeen.net>

Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com>

---

 src/exfat_fs.h |  1 +

 src/file.c     |  2 ++

 src/misc.c     | 14 +++++++++++++-

 src/namei.c    |  7 +++++++

 src/super.c    |  1 +

 5 files changed, 24 insertions(+), 1 deletion(-)

diff --git a/src/exfat_fs.h b/src/exfat_fs.h

index 67d4e46fb81003d0c367862ee986b37c80e7fa4e..d67fb8a6f770c28db8f1618c78fde493e2a4b965 100644

--- a/src/exfat_fs.h

+++ b/src/exfat_fs.h

@@ -507,6 +507,7 @@ void exfat_msg(struct super_block *sb, const char *lv, const char *fmt, ...)

 		__printf(3, 4) __cold;

 void exfat_get_entry_time(struct exfat_sb_info *sbi, struct timespec64 *ts,

 		u8 tz, __le16 time, __le16 date, u8 time_ms);

+void exfat_truncate_atime(struct timespec64 *ts);

 void exfat_set_entry_time(struct exfat_sb_info *sbi, struct timespec64 *ts,

 		u8 *tz, __le16 *time, __le16 *date, u8 *time_ms);

 unsigned short exfat_calc_chksum_2byte(void *data, int len,

diff --git a/src/file.c b/src/file.c

index 483f683757aa87420ba347afd3c9db9e94b8a14d..4f76764165cf6f63a99c5e192ab33685e8e987b7 100644

--- a/src/file.c

+++ b/src/file.c

@@ -273,6 +273,7 @@ int exfat_getattr(const struct path *path, struct kstat *stat,

 	struct exfat_inode_info *ei = EXFAT_I(inode);

 	generic_fillattr(inode, stat);

+	exfat_truncate_atime(&stat->atime);

 	stat->result_mask |= STATX_BTIME;

 	stat->btime.tv_sec = ei->i_crtime.tv_sec;

 	stat->btime.tv_nsec = ei->i_crtime.tv_nsec;

@@ -339,6 +340,7 @@ int exfat_setattr(struct dentry *dentry, struct iattr *attr)

 	}

 	setattr_copy(inode, attr);

+	exfat_truncate_atime(&inode->i_atime);

 	mark_inode_dirty(inode);

 out:

diff --git a/src/misc.c b/src/misc.c

index 14a3300848f6a0fb754b9d34bdacbc31b90f5d07..ebd2cbe3cbc11c2aede3819c414020b9344ec1f9 100644

--- a/src/misc.c

+++ b/src/misc.c

@@ -88,7 +88,8 @@ void exfat_get_entry_time(struct exfat_sb_info *sbi, struct timespec64 *ts,

 	if (time_ms) {

 		ts->tv_sec += time_ms / 100;

 		ts->tv_nsec = (time_ms % 100) * 10 * NSEC_PER_MSEC;

-	}

+	} else

+		ts->tv_nsec = 0;

 	if (tz & EXFAT_TZ_VALID)

 		/* Adjust timezone to UTC0. */

@@ -124,6 +125,17 @@ void exfat_set_entry_time(struct exfat_sb_info *sbi, struct timespec64 *ts,

 	*tz = EXFAT_TZ_VALID;

 }

+/*

+ * The timestamp for access_time has double seconds granularity.

+ * (There is no 10msIncrement field for access_time unlike create/modify_time)

+ * atime also has only a 2-second resolution.

+ */

+void exfat_truncate_atime(struct timespec64 *ts)

+{

+	ts->tv_sec = round_down(ts->tv_sec, 2);

+	ts->tv_nsec = 0;

+}

+

 unsigned short exfat_calc_chksum_2byte(void *data, int len,

 		unsigned short chksum, int type)

 {

diff --git a/src/namei.c b/src/namei.c

index a8681d91f56900107ea3df90e2b6dd986045a7bc..b72d782568b811ece222db0dd3575fd8bf2c958a 100644

--- a/src/namei.c

+++ b/src/namei.c

@@ -595,6 +595,7 @@ static int exfat_create(struct inode *dir, struct dentry *dentry, umode_t mode,

 	inode_inc_iversion(inode);

 	inode->i_mtime = inode->i_atime = inode->i_ctime =

 		EXFAT_I(inode)->i_crtime = current_time(inode);

+	exfat_truncate_atime(&inode->i_atime);

 	/* timestamp is already written, so mark_inode_dirty() is unneeded. */

 	d_instantiate(dentry, inode);

@@ -854,6 +855,7 @@ static int exfat_unlink(struct inode *dir, struct dentry *dentry)

 	inode_inc_iversion(dir);

 	dir->i_mtime = dir->i_atime = current_time(dir);

+	exfat_truncate_atime(&dir->i_atime);

 	if (IS_DIRSYNC(dir))

 		exfat_sync_inode(dir);

 	else

@@ -861,6 +863,7 @@ static int exfat_unlink(struct inode *dir, struct dentry *dentry)

 	clear_nlink(inode);

 	inode->i_mtime = inode->i_atime = current_time(inode);

+	exfat_truncate_atime(&inode->i_atime);

 	exfat_unhash_inode(inode);

 	exfat_d_version_set(dentry, inode_query_iversion(dir));

 unlock:

@@ -903,6 +906,7 @@ static int exfat_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)

 	inode_inc_iversion(inode);

 	inode->i_mtime = inode->i_atime = inode->i_ctime =

 		EXFAT_I(inode)->i_crtime = current_time(inode);

+	exfat_truncate_atime(&inode->i_atime);

 	/* timestamp is already written, so mark_inode_dirty() is unneeded. */

 	d_instantiate(dentry, inode);

@@ -1019,6 +1023,7 @@ static int exfat_rmdir(struct inode *dir, struct dentry *dentry)

 	inode_inc_iversion(dir);

 	dir->i_mtime = dir->i_atime = current_time(dir);

+	exfat_truncate_atime(&dir->i_atime);

 	if (IS_DIRSYNC(dir))

 		exfat_sync_inode(dir);

 	else

@@ -1027,6 +1032,7 @@ static int exfat_rmdir(struct inode *dir, struct dentry *dentry)

 	clear_nlink(inode);

 	inode->i_mtime = inode->i_atime = current_time(inode);

+	exfat_truncate_atime(&inode->i_atime);

 	exfat_unhash_inode(inode);

 	exfat_d_version_set(dentry, inode_query_iversion(dir));

 unlock:

@@ -1387,6 +1393,7 @@ static int exfat_rename(struct inode *old_dir, struct dentry *old_dentry,

 	inode_inc_iversion(new_dir);

 	new_dir->i_ctime = new_dir->i_mtime = new_dir->i_atime =

 		EXFAT_I(new_dir)->i_crtime = current_time(new_dir);

+	exfat_truncate_atime(&new_dir->i_atime);

 	if (IS_DIRSYNC(new_dir))

 		exfat_sync_inode(new_dir);

 	else

diff --git a/src/super.c b/src/super.c

index ee42ecf59059a6c9bf61f5b6ec19efde21a4d897..0565d5539d57c6678c81997228dc3b8116eb864c 100644

--- a/src/super.c

+++ b/src/super.c

@@ -342,6 +342,7 @@ static int exfat_read_root(struct inode *inode)

 	exfat_save_attr(inode, ATTR_SUBDIR);

 	inode->i_mtime = inode->i_atime = inode->i_ctime = ei->i_crtime =

 		current_time(inode);

+	exfat_truncate_atime(&inode->i_atime);

 	exfat_cache_init_inode(inode);

 	return 0;

 }

-- 

2.31.1