From mboxrd@z Thu Jan 1 00:00:00 1970 From: Kent Overstreet Subject: Re: [bcachefs] Mounting the same device multiple times now works Date: Wed, 12 Aug 2015 21:03:11 -0800 Message-ID: <20150813050311.GA10664@kmo-pixel> References: <20150811083453.GA29708@kmo-pixel> <1439315982.19144.7.camel@ssi> <20150812013853.GA2192@kmo-pixel> <1439364962.5775.4.camel@hasee> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from mail-pa0-f41.google.com ([209.85.220.41]:35740 "EHLO mail-pa0-f41.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750713AbbHMFDP (ORCPT ); Thu, 13 Aug 2015 01:03:15 -0400 Received: by pacgr6 with SMTP id gr6so29484039pac.2 for ; Wed, 12 Aug 2015 22:03:14 -0700 (PDT) Content-Disposition: inline In-Reply-To: <1439364962.5775.4.camel@hasee> Sender: linux-bcache-owner@vger.kernel.org List-Id: linux-bcache@vger.kernel.org To: Ming Lin Cc: linux-bcache@vger.kernel.org On Wed, Aug 12, 2015 at 12:36:02AM -0700, Ming Lin wrote: > On Tue, 2015-08-11 at 17:38 -0800, Kent Overstreet wrote: > > On Tue, Aug 11, 2015 at 10:59:42AM -0700, Ming Lin wrote: > > > On Tue, 2015-08-11 at 00:34 -0800, Kent Overstreet wrote: > > > > Like in other filesystems, you can now do > > > > > > > > mount /dev/sda1 /foo > > > > mount /dev/sda1 /bar > > > > > > > > What this really means is that if the udev hook has registered the bcache device > > > > via the old style sysfs interface for caching, you'll still be able to mount the > > > > device like normal. > > > > > > Thanks! > > > > > > BTW, could you share the bcachefs long term development plans and short > > > term high priority tasks? > > > > Right now, my main priority is stabilizing it and making it usable - fixing all > > the things that people are going to trip over when they try it out. I want to > > get it somewhat more polished before I announce on linux-fsdevel. > > > > The big thing I'm working on at the moment is debugging atomic renames, I had to > > back that code out at the last minute. > > > > > I'd like to pick something to work on. Probably the debugfs tool you > > > mentioned or other things? > > > > One thing that would actually be really helpful is more benchmarking vs. > > ext4/xfs - identifying areas where there's still more performance work to do. > > > > The debugfs tool is definitely important but that's a longer term thing. If > > you're feeling productive like that feel free to keep going with it. > > > > Really though right now the main thing we need is more testing and debugging. > > I have run xfstests. Here is the results for generic tests. > http://minggr.net/pub/bcachefs/xfstests.log > > One thing is fallocate not supported yet. Is it known? > > root@bee:~# mount |grep bcache > /dev/sda on /mnt/test type bcache (rw,relatime) > > root@bee:~# fallocate -l 4096 /mnt/test/hello.c > fallocate: /mnt/test/hello.c: fallocate failed: Operation not supported I do have code for fpunch/fcollapse in another branch - but it's not entirely working yet. Fallocate itself is going to be more involved, we'll need some sort of persistent reservations which are going to be a pain... should probably look and find out what semantics btrfs implements first.