From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from exprod5og116.obsmtp.com ([64.18.0.147]:52155 "EHLO exprod5og116.obsmtp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755129Ab3JXWpf (ORCPT ); Thu, 24 Oct 2013 18:45:35 -0400 Date: Fri, 25 Oct 2013 00:46:08 +0200 From: Karl Kiniger To: Chris Murphy Cc: Btrfs BTRFS Subject: Re: Why cannot I move a read-only snapshot around? Message-ID: <20131024224608.GA14904@kipc2.localdomain> References: <20131024152955.GA6110@kipc2.localdomain> <1D7328F7-EB4F-4C3F-8EAB-2EDB6331F77E@colorremedies.com> <20131024215715.GA14128@kipc2.localdomain> <97FC1966-5DC7-488F-8A6C-C8C8B2EB8490@colorremedies.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 In-Reply-To: <97FC1966-5DC7-488F-8A6C-C8C8B2EB8490@colorremedies.com> Sender: linux-btrfs-owner@vger.kernel.org List-ID: On Thu 131024, Chris Murphy wrote: > dr--------. 1 chris chris 0 Oct 24 16:15 donotmove > > [chris@f20s ~]$ mv donotmove/ Videos/ > mv: cannot move ‘donotmove/’ to ‘Videos/donotmove’: Permission denied' > > I own that directory. But because it's read only, I can't move it because moving it changes it. Of course if I become root, that overrides posix permissions, but the readonly status of a subvolume isn't like posix permissions and I see now reason why root should be able to modify it. And moving it does modify it. tries this all as root. drwxr-xr-x. 1 root root 734 Oct 24 16:41 @20131024 (this is a r/o snap) It looks to me similar to a read-only mounted filesystem: pc2:/u2/F19/@20131024# touch foo touch: cannot touch ‘foo’: Read-only file system In what way would a r/o snapshot be modified because of moving its "mount point" ? No one is ever doing something inside. Karl > Chris Murphy