From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jan Kara Date: Thu, 1 Mar 2012 12:41:34 +0100 Subject: [Cluster-devel] [PATCH 00/11 v2] Push file_update_time() into .page_mkwrite Message-ID: <1330602103-8851-1-git-send-email-jack@suse.cz> List-Id: To: cluster-devel.redhat.com MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit 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 *shiver*. Changes since v1: * Dropped patches for filesystems which don't need them * Added some acks * Improved sysfs patch by Alex Elder's suggestion Andrew, would you be willing to merge these patches via your tree? Honza CC: Jaya Kumar CC: Sage Weil CC: ceph-devel at vger.kernel.org CC: Steve French CC: linux-cifs at vger.kernel.org CC: Eric Van Hensbergen CC: Ron Minnich CC: Latchesar Ionkov CC: v9fs-developer at lists.sourceforge.net CC: Miklos Szeredi CC: fuse-devel at lists.sourceforge.net CC: Steven Whitehouse CC: cluster-devel at redhat.com CC: Greg Kroah-Hartman