fat: Add allow_utime option

Normally utime(2) checks current process is owner of the file, or it
has CAP_FOWNER capability.  But FAT filesystem doesn't have uid/gid as
on disk info, so normal check is too unflexible.

With this option you can relax it.

Signed-off-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/include/linux/msdos_fs.h b/include/linux/msdos_fs.h
index c4bed98..81fb9bc 100644
--- a/include/linux/msdos_fs.h
+++ b/include/linux/msdos_fs.h
@@ -195,6 +195,7 @@
 	char *iocharset;          /* Charset used for filename input/display */
 	unsigned short shortname; /* flags for shortname display/create rule */
 	unsigned char name_check; /* r = relaxed, n = normal, s = strict */
+	unsigned short allow_utime;/* permission for setting the [am]time */
 	unsigned quiet:1,         /* set = fake successful chmods and chowns */
 		 showexec:1,      /* set = only set x bit for com/exe/bat */
 		 sys_immutable:1, /* set = system files are immutable */