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From: Ulrich Drepper <drepper@redhat.com>
To: Linux Kernel <linux-kernel@vger.kernel.org>
Subject: filesystem time stamp resolution
Date: Thu, 26 Feb 2009 15:18:04 -0800	[thread overview]
Message-ID: <49A7232C.6050808@redhat.com> (raw)

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How can code at userlevel (e.g., glibc) determine the resolution of the
a filesystem timestamp?

Boundary condition:

- - I cannot create or modify a file since the information must also
  be available for filesystems where the caller has no write permission

- - it has to work going forward (i.e., hardcoding information is no good
  idea)

One acceptable solution (for me) would be to have directories for the
filesystem types under /proc/fs (or /sys/fs) which show this
information.  E.g.:

  /proc/fs/ext4/timestamp-resolution

Measured in nano-seconds or so.

As a bonus have symlinks like

  /proc/fs/ef53 -> /proc/fs/ext4

(i.e., map the superblock magic number to a name.  But I can live with
this missing.)

As a second bonus any help for network filesystems would be good but.

Do I miss anything that is there already?

- --
➧ Ulrich Drepper ➧ Red Hat, Inc. ➧ 444 Castro St ➧ Mountain View, CA ❖
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             reply	other threads:[~2009-02-26 23:18 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-02-26 23:18 Ulrich Drepper [this message]
2009-02-26 23:54 ` filesystem time stamp resolution Al Viro
2009-02-26 23:57   ` Ulrich Drepper
2009-02-27  0:19     ` Christoph Hellwig
2009-02-27  8:48 ` Andi Kleen
2009-02-27 22:01   ` Ulrich Drepper
2009-02-27 22:23     ` Peter Staubach

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