On Tue, May 15, 2012 at 07:59:11PM +0200, Marco Stornelli wrote: > Only a really really stupid question (I don't know NFS protocol well > enough). In 3.3 kernel, I see that only ext4 uses MS_I_VERSION, so I > wonder: if i_version change it's needed for exportable fs and so for > nfs, other exportable fs? Yes, it's needed for others as well. I believe btrfs and xfs are both adding it. We're currently using ctime for the nfs change attribute. That's effectively jiffy granularity. So to see the problem at a minimum you'd need two writes to be processed within one jiffy, and a stat to come between them. But that's a correctness problem, and we'd like to see it fixed before it becomes more common. More generally, it's useful to be able to ask whether a file changed without rereading all its data, and a clock that registers every change and is consistent across a filesystem sounds difficult to scale. We may eventually find we need something like this outside nfs. --b. -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
