From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from userp2130.oracle.com ([156.151.31.86]:51856 "EHLO userp2130.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726014AbeLCSW2 (ORCPT ); Mon, 3 Dec 2018 13:22:28 -0500 Date: Mon, 3 Dec 2018 10:22:17 -0800 From: "Darrick J. Wong" Subject: Re: [PATCH 07/11] vfs: copy_file_range should update file timestamps Message-ID: <20181203182217.GY8125@magnolia> References: <20181203083416.28978-1-david@fromorbit.com> <20181203083416.28978-8-david@fromorbit.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: linux-unionfs-owner@vger.kernel.org To: Olga Kornievskaia Cc: Amir Goldstein , david@fromorbit.com, linux-fsdevel@vger.kernel.org, linux-xfs@vger.kernel.org, linux-nfs , linux-unionfs@vger.kernel.org, ceph-devel@vger.kernel.org, linux-cifs@vger.kernel.org List-ID: On Mon, Dec 03, 2018 at 12:33:50PM -0500, Olga Kornievskaia wrote: > On Mon, Dec 3, 2018 at 5:47 AM Amir Goldstein wrote: > > > > On Mon, Dec 3, 2018 at 10:34 AM Dave Chinner wrote: > > > > > > From: Dave Chinner > > > > > > Timestamps are not updated right now, so programs looking for > > > timestamp updates for file modifications (like rsync) will not > > > detect that files have changed. We are also accessing the source > > > data when doing a copy (but not when cloning) so we need to update > > > atime on the source file as well. > > > > > > Signed-off-by: Dave Chinner > > > --- > > > fs/read_write.c | 10 ++++++++++ > > > 1 file changed, 10 insertions(+) > > > > > > diff --git a/fs/read_write.c b/fs/read_write.c > > > index 3b101183ea19..3288db1d5f21 100644 > > > --- a/fs/read_write.c > > > +++ b/fs/read_write.c > > > @@ -1576,6 +1576,16 @@ static ssize_t do_copy_file_range(struct file *file_in, loff_t pos_in, > > > { > > > ssize_t ret; > > > > > > + /* Update source timestamps, because we are accessing file data */ > > > + file_accessed(file_in); > > > + > > > + /* Update destination timestamps, since we can alter file contents. */ > > > + if (!(file_out->f_mode & FMODE_NOCMTIME)) { > > > + ret = file_update_time(file_out); > > > + if (ret) > > > + return ret; > > > + } > > > + > > > > If there is a consistency about who is responsible of calling file_accessed() > > and file_update_time() it eludes me. grep tells me that they are mostly > > handled by filesystem code or generic helpers called by filesystem code > > and not in the vfs helpers. > > > > FMODE_NOCMTIME seems like an xfs specific flag (for DMAPI?), which > > most generic callers of file_update_time() completely ignore. > > This seems like another argument in favor of leaving the responsibility > > of the timestamp updates to the filesystem. > > > > Maybe I am missing something? > > > > I had similar question before about who is responsible for doing the > checks. I agree that attributes should be updated for the case when no > filesystem support exist for copy_file_range() but this code does it > for all the cases. I also wonder if it's appropriate to update the > attributes before the copy is actually done? The other functions that change file contents (write, clonerange) update mtime and remove suid before initiating the operation. For mtime I think we should maintain consistent behavior, and for suid removal we definitely need to revoke that before we change the file contents. --D > > Thanks, > > Amir.