From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mike Fedyk Subject: Default to read-only on snapshot creation and have a flag if snapshot should be writable (was: [PATCH 0/5] btrfs: Readonly snapshots) Date: Mon, 29 Nov 2010 12:02:28 -0800 Message-ID: Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Cc: linux-btrfs@vger.kernel.org, Sage Weil To: Li Zefan Return-path: List-ID: On Mon, Nov 29, 2010 at 12:02 AM, Li Zefan wrote: > (Cc: Sage Weil for changes in async snapshots) > > This patchset adds readonly-snapshots support. You can create a > readonly snapshot, and you can also set a snapshot readonly/writable > on the fly. > > A few readonly checks are added in setattr, permission, remove_xattr > and set_xattr callbacks, as well as in some ioctls. > Great work! I have a suggestion on defaults when snapshots are created. I think they should default to being read-only and if they are meant to be read-write a flag can be set at creation time (and changable at a later time as well of course). This way user/admin preconceptions of a snapshot being read-only can be enforced by default, and the exception when you want a read-write snapshot can be available with a switch at the cli level (and probably a flag at the ioctl level). It gives one more natural distinction between a snapshot and a subvolume at the user conceptual level. What do you think?