From: Dave Chinner <david@fromorbit.com>
To: Ted Ts'o <tytso@mit.edu>
Cc: Thomas Lindroth <thomas.lindroth@gmail.com>, linux-ext4@vger.kernel.org
Subject: Re: e4defrag modifies folder's mtime.
Date: Wed, 4 Jan 2012 18:43:57 +1100 [thread overview]
Message-ID: <20120104074357.GC17026@dastard> (raw)
In-Reply-To: <20120104052718.GB13438@thunk.org>
On Wed, Jan 04, 2012 at 12:27:18AM -0500, Ted Ts'o wrote:
> On Wed, Jan 04, 2012 at 03:53:18PM +1100, Dave Chinner wrote:
> >
> > xfs_fsr doesn't use these donor files to avoid mtime updates - it
> > uses invisible IO (i.e. O_NOATIME|O_NOCMTIME) to do that.
>
> O_NOCMTIME doesn't exist yet. From include/linux/fs.h:
>
> /*
> * Don't update ctime and mtime.
> *
> * Currently a special hack for the XFS open_by_handle ioctl, but we'll
> * hopefully graduate it to a proper O_CMTIME flag supported by open(2) soon.
> */
> #define FMODE_NOCMTIME ((__force fmode_t)0x800)
>
> I'd have to check, but it wouldn't surprise me if glibc is filtering
> out all fcntl flags it doesn't understand, so for now, this is an
> XFS-only special...
Sounds to me like e2defrag needs it, so perhaps it should finally
be made a proper open flag like the comment says rather than
inventing some other way of solving the problem....
Cheers,
Dave.
--
Dave Chinner
david@fromorbit.com
prev parent reply other threads:[~2012-01-04 7:44 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-01-01 20:12 e4defrag modifies folder's mtime Thomas Lindroth
2012-01-03 20:34 ` Ted Ts'o
2012-01-04 4:53 ` Dave Chinner
2012-01-04 5:27 ` Ted Ts'o
2012-01-04 7:43 ` Dave Chinner [this message]
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