On 07/02/2012 06:00 PM, Ilya Dryomov wrote:

On Mon, Jul 02, 2012 at 10:07:42AM +0800, Liu Bo wrote:

quoted

On 06/29/2012 06:21 PM, Ilya Dryomov wrote:

quoted

On Fri, Jun 29, 2012 at 06:00:36PM +0800, Liu Bo wrote:

quoted

Setting subvolume/snapshot readonly has been missing for a long time.

With this patch, we can set a subvolume/snapshot readonly via:

o    btrfs subvolume set-ro <path>

Alexander's 'btrfs property' patches do exactly this, but in a much more
generic and extensible way.  'btrfs property' subgroup provides a
uniform interface for getting and setting properties of filesystem
objects in general, not only those of subvolumes and snapshots.  It
provides a much better user interface, and it also allows us to easily
rethink kernel-user interface for generic get/set in future.

Thanks for the explanation!

But I prefer keeping the current categories {subvolume,filesystem,device,...}:

o Compatibility, we cannot remove the old commands until we make sure that no users will
  use them.

We are not going to remove old commands any time soon.  However, adding
new ones that clearly fall into get/set category, is not a good idea.
Especially when there is a generic interface on its way.

quoted

o We've three properties {default, readonly, lable}, is it worthy making another new interface?

It's not just about subvolumes.  There will be a lot more properties on
the table as filesystem matures, for example device speeds, subvolume
profiles, quotas.

quoted

o Current categories are clear and clean.

Once again, it's not just about subvolumes.  Current categories are
indeed clear, but adding two commands for each non-trivial property that
comes up in future does not seem practical to me.

I see, that's reasonable. :)

Besides set/get-ro and get-default, I also want to have 'btrfs subvolume list' work as 'ls', that is,
it can list not only all of items, but also a single item.

And I have made a patch for that (it refers to [PATCH 3/3] Btrfs-progs: add 's' option for 'btrfs subvolume list').

What's your opinion about it?

thanks,
liubo

Thanks,

		Ilya
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