From mboxrd@z Thu Jan  1 00:00:00 1970
From: Ric Wheeler <ricwheeler@gmail.com>
Subject: Re: [dm-devel] generic wrappers for multi-device FS operations
Date: Tue, 08 Mar 2011 13:13:51 -0500
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To: Wendy Cheng <s.wendy.cheng@gmail.com>
Cc: Linux FS Devel <linux-fsdevel@vger.kernel.org>, device-mapper development <dm-devel@redhat.com>, Karel Zak <kzak@redhat.com>, Jim Meyering <jim@meyering.net>, Chris Mason <chris.mason@oracle.com>, Josef Bacik <josef@redhat.com>
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On 03/08/2011 01:05 PM, Wendy Cheng wrote:
>> On Tue, Mar 08, 2011 at 12:04:25PM -0500, Ric Wheeler wrote:
>>> To make this trivial to do for users, I think that it would be really
>>> nice to have a two-level wrappers for things like resize, add a volume,
>>> shrink, etc. Similar to the way we have mount or fsck invoke file system
>>> specific bits.
>>> Good idea? Bad idea?
> So the "resize" is on the filesystem, not the volume ? The "grow" part
> is probably easy. Unfortunately, the "shrink" may not be easy for some
> of the filesystems:
>
> -- Wendy

I think any "standard" operation would be allowed to fail with "notsupported" 
effectively. Shrink is definitely a challenge & even when it works, it often has 
performance implications.

I think that adding support to fsadm might be the easy path forward, but we 
would need to be able to do at least a handful of more advanced things (add a 
whole device for example).

Ric