From: "J. Bruce Fields" Subject: Re: [PATCH 3/5] ext4: Implement project ID support for ext4 filesystem Date: Fri, 12 Mar 2010 15:07:29 -0500 Message-ID: <20100312200728.GA13448@fieldses.org> References: <1267727677-11956-1-git-send-email-dmonakhov@openvz.org> <1267727677-11956-2-git-send-email-dmonakhov@openvz.org> <1267727677-11956-3-git-send-email-dmonakhov@openvz.org> <1267727677-11956-4-git-send-email-dmonakhov@openvz.org> <20100311120623.GC4706@infradead.org> <877hpjj88k.fsf@openvz.org> <20100311220133.GL1497@thunk.org> <87pr39evhi.fsf@openvz.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: tytso@mit.edu, Andreas Dilger , Christoph Hellwig , linux-fsdevel@vger.kernel.org, linux-ext4@vger.kernel.org To: Dmitry Monakhov Return-path: Content-Disposition: inline In-Reply-To: <87pr39evhi.fsf@openvz.org> Sender: linux-fsdevel-owner@vger.kernel.org List-Id: linux-ext4.vger.kernel.org On Fri, Mar 12, 2010 at 12:32:09PM +0300, Dmitry Monakhov wrote: > tytso@mit.edu writes: > > > On Thu, Mar 11, 2010 at 12:54:46PM -0700, Andreas Dilger wrote: > >> A second possibility (if there is really no desire to have more than > >> a single project ID per inode) is to add a field to the "large" > >> inode for ext4, though that doesn't help filesystems that were not > >> formatted that way, and it also consumes space in all inodes even if > >> this feature is not used. > > > > The big question that I'm still uncertain about is how often are > > people going to be using this feature, and how many project ID's do we > > really need? I know Dimitry believes this is going to be the greatest > > thing since sliced bread, but even for people running virtualization, > > I'm not sure how many folks really will consider it critical. > Most of our customers (hosting providers) use quota, otherwise > it is impossible to restrict disk usage. Currently they have to > perform full quotecheck after power failure. Which result in huge > service down time. If we able to use journalled quota all problems > will be solved. > Also NFS people was interesting in projectid feature. They want to > use it for creating safe file-handles. > http://marc.info/?l=linux-fsdevel&m=126634832431306&w=2 By the way, have you looked at all at what it would take to be able to encode and decode filehandles with projectid's in them? --b.