From: Christoph Hellwig Subject: Re: [PATCH 4/4] Adds ioctl interface support for ext4 project Date: Wed, 24 Sep 2014 09:26:34 -0700 Message-ID: <20140924162634.GA16886@infradead.org> References: <1411567470-31799-1-git-send-email-lixi@ddn.com> <1411567470-31799-5-git-send-email-lixi@ddn.com> <20140924162507.GC27000@quack.suse.cz> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Li Xi , linux-fsdevel@vger.kernel.org, linux-ext4@vger.kernel.org, linux-api@vger.kernel.org, tytso@mit.edu, adilger@dilger.ca, viro@zeniv.linux.org.uk, hch@infradead.org, dmonakhov@openvz.org, xfs@oss.sgi.com To: Jan Kara Return-path: Received: from bombadil.infradead.org ([198.137.202.9]:60345 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751078AbaIXQ0f (ORCPT ); Wed, 24 Sep 2014 12:26:35 -0400 Content-Disposition: inline In-Reply-To: <20140924162507.GC27000@quack.suse.cz> Sender: linux-ext4-owner@vger.kernel.org List-ID: On Wed, Sep 24, 2014 at 06:25:07PM +0200, Jan Kara wrote: > On Wed 24-09-14 22:04:30, Li Xi wrote: > > This patch adds ioctl interface for setting/getting project of ext4. > The patch looks good to me. I was just wondering whether it won't be > useful to add an ioctl() which isn't ext4 specific. We could just extend > ->setattr() to allow setting of project ID (most filesystems would just > return -EOPNOTSUPP but ext4 and xfs could do the right thing) and then call > ->setattr from the generic ioctl. That way userspace won't have to care > about filesystem type when setting project ID... What do others think? Absolutely. In general I also wonder why this patch doesn't implement the full XFS API. Maybe there is a reason it was considered and rejected, but it would be helpful to document why.