[sheepdog] [PATCH 4/4] dog: make repairing vdi optional

[MORITA Kazutaka]

At Thu, 22 Aug 2013 16:13:49 +0800,
Liu Yuan wrote:
> 
> On Thu, Aug 22, 2013 at 05:06:20PM +0900, MORITA Kazutaka wrote:
> > At Thu, 22 Aug 2013 15:53:30 +0800,
> > Liu Yuan wrote:
> > > 
> > > On Thu, Aug 22, 2013 at 04:49:18PM +0900, MORITA Kazutaka wrote:
> > > > At Thu, 22 Aug 2013 15:37:44 +0800,
> > > > Liu Yuan wrote:
> > > > > 
> > > > > On Thu, Aug 22, 2013 at 09:30:05AM +0200, Valerio Pachera wrote:
> > > > > > Sorry guys if I intrude in this list.
> > > > > > 
> > > > > > In my opinion, form user point of view, it would be nice to have a
> > > > > > "read only" check that could be run with a running vm.
> > > > > > In case problems are reported, then the user could shutdown the guest
> > > > > > when he can, and run the check "read write" (auto repair).
> > > > > > 
> > > > > > Similar to
> > > > > > xfs_check -n <device>  (no repair)
> > > > > > xfs_check <device> (repair)
> > > > > > 
> > > > > 
> > > > > This looks reasonable to me.
> > > > 
> > > > Does it means that it's okay for you if auto-repar is disabled by
> > > > default?  If we have a way to do online check, either is okay to me.
> > > 
> > > I think default to be disabled (safest option) looks fine to me. Can we simply
> > > call it 'repair' instead of 'auto-repair'? I have no clue what 'auto' means when
> > > I see it.
> > 
> > Ah, I may see your point.
> > With my patches,
> > 
> >  - vdi check: shows a confirm message to repair the vdi when an error
> >               is found.
> >  - vdi check -A: repair the vdi without asking (I said this as a auto-repair)
> > 
> > but you mean 
> > 
> >  - vdi check: check only
> >  - vdi check -r: check and repiar
> > 
> > right?
> 
> Yes
> 
> >
> > Then how about creating another command 'vdi repair' to fix the vdi?
> > I noticed that xfs has xfs_check and xfs_repair.
> 
> vdi check # check only?
> vdi repair # check and repair?
> 
> But we'll duplicate many advanced commands for check and repair. So I think
> 
> vdi check [ -r -o {consistency,inode...} ] as a bundle is better.

I still think -o {optlist} is not a good idea because

 - Users cannot know which option is enabled by default and which
   option they should turn on.
 - It's difficult to maintain bash_completion_dog and dog.8 if we
   allow the option list.

How about adding only one option "-o, --online", which filters unsafe
check/repair when the vdi is in use?

E.g.

$ vdi check                   # This tries full check.
$ vdi check --online          # This filters consistency check since it
                              # doesn't work if the vdi is in use

$ vdi check --repair          # This tries full check and repair
$ vdi check --repair --online # This does only existence check since
                              # the other tests are not safe against online vdi.

Thanks,

Kazutaka