[LU-1118] Push file_update_time() into .page_mkwrite

Fri, 22 Apr 2016 17:54:45 +0000

Please add a check for this so that it isn't forgotten. This isn't something that will cause a compile error, so it could easily be missed when porting to a new kernel.

Cheers, Andreas

Begin forwarded message:

> From: Jan Kara <jack@suse.cz>
> Date: 16 February, 2012 6:46:08 MST
> To: LKML <linux-kernel@vger.kernel.org>
> Cc: linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, Andrew Morton <akpm@linux-foundation.org>, Eric Sandeen <sandeen@redhat.com>, Dave Chinner <david@fromorbit.com>, Jan Kara <jack@suse.cz>, Peter Zijlstra <a.p.zijlstra@chello.nl>, Ingo Molnar <mingo@elte.hu>, Paul Mackerras <paulus@samba.org>, Arnaldo Carvalho de Melo <acme@ghostprotocols.net>, Jaya Kumar <jayalk@intworks.biz>, Sage Weil <sage@newdream.net>, ceph-devel@vger.kernel.org, Steve French <sfrench@samba.org>, linux-cifs@vger.kernel.org, Eric Van Hensbergen <ericvh@gmail.com>, Ron Minnich <rminnich@sandia.gov>, Latchesar Ionkov <lucho@ionkov.net>, v9fs-developer@lists.sourceforge.net, Miklos Szeredi <miklos@szeredi.hu>, fuse-devel@lists.sourceforge.net, Steven Whitehouse <swhiteho@redhat.com>, cluster-devel@redhat.com, Greg Kroah-Hartman <gregkh@linuxfoundation.org>, Trond Myklebust <Trond.Myklebust@netapp.com>, linux-nfs@vger.kernel.org
> Subject: [PATCH 00/11] Push file_update_time() into .page_mkwrite
>
> Hello,
>
> to provide reliable support for filesystem freezing, filesystems need to have
> complete control over when metadata is changed. In particular,
> file_update_time() calls from page fault code make it impossible for
> filesystems to prevent inodes from being dirtied while the filesystem is
> frozen.
>
> To fix the issue, this patch set changes page fault code to call
> file_update_time() only when ->page_mkwrite() callback is not provided. If the
> callback is provided, it is the responsibility of the filesystem to perform
> update of i_mtime / i_ctime if needed. We also push file_update_time() call
> to all existing ->page_mkwrite() implementations if the time update does not
> obviously happen by other means. If you know your filesystem does not need
> update of modification times in ->page_mkwrite() handler, please speak up and
> I'll drop the patch for your filesystem.
>
> As a side note, an alternative would be to remove call of file_update_time()
> from page fault code altogether and require all filesystems needing it to do
> that in their ->page_mkwrite() implementation. That is certainly possible
> although maybe slightly inefficient and would require auditting 100+
> vm_operations_structs shake.
>
> If I get acks on these patches, Andrew, would you be willing to take these
> patches?
>
> Honza
>

Whamcloud Community JIRA

[LU-1118] Push file_update_time() into .page_mkwrite