Re: [RFC] set MS_NOATIME on FAT ?

[Werner Almesberger <werner@almesberger.net>]

OGAWA Hirofumi wrote:
> Right. However, if you need NOATIME, you can set it with mount
> options.

Yes, of course. It just seems clearer to me to avoid the useless
"inode" writes by default.

> And I think, we just need to fix ->adate, no need to change
> default options.

In the case of non-VFAT, there's also the issue that pretending to
support atime causes atime to jump back and forth unpredictably,
depending on when the inode is evicted from memory. (And the low
adate resolution means that even VFAT will have a similar problem.)

But I guess if nobody complained in the last twelve or so years,
we're in no hurry to fix that ;-) (And in case we are, patch
below.)

Thanks,
- Werner

---------------------------------- cut here -----------------------------------

Signed-off-by: Werner Almesberger <werner@almesberger.net>

--- linux-2.6.11-orig/fs/fat/inode.c	Wed Mar  2 04:38:08 2005
+++ linux-2.6.11/fs/fat/inode.c	Tue Mar 15 07:35:06 2005
@@ -414,6 +484,8 @@ static void __exit fat_destroy_inodecach
 static int fat_remount(struct super_block *sb, int *flags, char *data)
 {
 	*flags |= MS_NODIRATIME;
+	if (!MSDOS_SB(sb)->options.isvfat)
+		*flags |= MS_NOATIME;
 	return 0;
 }
 
@@ -1059,6 +1131,8 @@ int fat_fill_super(struct super_block *s
 	memset(sbi, 0, sizeof(struct msdos_sb_info));
 
 	sb->s_flags |= MS_NODIRATIME;
+	if (!isvfat)
+		sb->s_flags |= MS_NOATIME;
 	sb->s_magic = MSDOS_SUPER_MAGIC;
 	sb->s_op = &fat_sops;
 	sb->s_export_op = &fat_export_ops;

-- 
  _________________________________________________________________________
 / Werner Almesberger, Buenos Aires, Argentina     werner@almesberger.net /
/_http://www.almesberger.net/____________________________________________/