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

From: Eric Blake <ebb9@byu.net>
To: ctrn3e8 <ctrn3e8@gmail.com>
Cc: =?ISO-8859-1?Q?Jean-Pie?=@oss.sgi.com,
	"Miklos Szeredi" <miklos@szeredi.hu>,
	fuse-devel@lists.sourceforge.net,
	bug-coreutils <bug-coreutils@gnu.org>,
	"rre André" <jean-pierre.andre@wanadoo.fr>,
	"Linux Kernel Mailing List" <linux-kernel@vger.kernel.org>,
	xfs@oss.sgi.com, "Christoph Hellwig" <hch@lst.de>,
	"OGAWA Hirofumi" <hirofumi@mail.parknet.co.jp>
Subject: Re: [fuse-devel] utimensat fails to update ctime
Date: Wed, 23 Dec 2009 17:50:04 -0700	[thread overview]
Message-ID: <4B32BABC.7020908@byu.net> (raw)
In-Reply-To: <4B32B303.6070807@gmail.com>

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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@byu.net
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