linux-kernel - Re: [fuse-devel] utimensat fails to update ctime

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Date:	Wed, 23 Dec 2009 17:50:04 -0700
From:	Eric Blake <ebb9@....net>
To:	ctrn3e8 <ctrn3e8@...il.com>
CC:	OGAWA Hirofumi <hirofumi@...l.parknet.co.jp>,
	Jean-Pierre André 
	<jean-pierre.andre@...adoo.fr>, fuse-devel@...ts.sourceforge.net,
	Miklos Szeredi <miklos@...redi.hu>,
	Christoph Hellwig <hch@....de>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	xfs@....sgi.com, bug-coreutils <bug-coreutils@....org>
Subject: Re: [fuse-devel] utimensat fails to update ctime

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According to ctrn3e8 on 12/23/2009 5:17 PM:
> The strace has the following function call  (and it may be because I am
> looking at the trace rather than the actual source):

> utimensat(0, NULL, {UTIME_OMIT, UTIME_NOW}, 0) = 0

> The two don't seem to match.  Is this just because of the way the trace is printed?

Yes.  When the tv_nsec field is UTIME_OMIT or UTIME_NOW, the tv_sec field
is irrelevant.  Therefore, to save on space, strace omits the tv_sec field
in its output.  But rest assured that the kernel has read access to all
four 32-bit words located at the timespec pointer passed in the syscall.

> No mention of ntfs-3g support for nanosecond time stamping.

Read the rest of the thread on lkml - that is a known issue, which will
probably not be solved any sooner than January (all the patches this week
only dealt with mishandling of UTIME_OMIT).

- --
Don't work too hard, make some time for fun as well!

Eric Blake             ebb9@....net
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