Re: Default to read-only on snapshot creation and have a flag if snapshot should be writable (was: [PATCH 0/5] btrfs: Readonly snapshots)

[David Arendt <admin@prnet.org>]

On 11/29/10 21:02, Mike Fedyk wrote:
> On Mon, Nov 29, 2010 at 12:02 AM, Li Zefan<lizf@cn.fujitsu.com>  wrote:
>> (Cc: Sage Weil<sage@newdream.net>  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?
> --
> To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
Hi,

I completely agree with you. I think lots of people use snapshots for 
backup purposes and these ones shouldn't be writable.

Bye,
David Arendt