reiser4 not supporting quota

reiser4 not supporting quota

[Dudi Indrasetiadi]

Sorry for this ``not so smart'' question, is there quota support in
reiser4? Or quota is not in the main idea of reiser4?

Thanks a lot.

-- 
<idud>

Re: reiser4 not supporting quota

[Jan Kara]

> Sorry for this ``not so smart'' question, is there quota support in
> reiser4? Or quota is not in the main idea of reiser4?
  There is not quota support for Reiser4. I'm looking into it but first
I have to come up with a reasonable semantics + idea of efficient
implementation :) The framework of plugins and the fact that Reiser4 first
overestimates the needed space and then releases it (and eventually
uses also some of the "reserved" space) makes the quota implementation harder
than in other filesystems...

								Honza

Re: reiser4 not supporting quota

[Vladimir Saveliev]

Hello

On Tue, 2005-04-05 at 14:37, Jan Kara wrote:
> > Sorry for this ``not so smart'' question, is there quota support in
> > reiser4? Or quota is not in the main idea of reiser4?
>   There is not quota support for Reiser4. I'm looking into it but first
> I have to come up with a reasonable semantics + idea of efficient
> implementation :) The framework of plugins and the fact that Reiser4 first
> overestimates the needed space and then releases it (and eventually
> uses also some of the "reserved" space) makes the quota implementation harder
> than in other filesystems...

Wouldn't be simpler if quota limited a user in terms of number of
files/total size of files and not in term of space used by filesystem
internally to store those files?

I think that anyway it is not possible to calculate exactly number of
bytes of disk space reiserX filesystem allocates to store a file in
filesystem because of rebalancing.

For quota in reiser4 : we probably need to make it "transactional".
Do you think we can make quota counter update in the same transaction
with the quoted operation?

Re: reiser4 not supporting quota

[Jan Kara]

  Hello,

> On Tue, 2005-04-05 at 14:37, Jan Kara wrote:
> > > Sorry for this ``not so smart'' question, is there quota support in
> > > reiser4? Or quota is not in the main idea of reiser4?
> >   There is not quota support for Reiser4. I'm looking into it but first
> > I have to come up with a reasonable semantics + idea of efficient
> > implementation :) The framework of plugins and the fact that Reiser4 first
> > overestimates the needed space and then releases it (and eventually
> > uses also some of the "reserved" space) makes the quota implementation harder
> > than in other filesystems...
> 
> Wouldn't be simpler if quota limited a user in terms of number of
> files/total size of files and not in term of space used by filesystem
> internally to store those files?
> 
> I think that anyway it is not possible to calculate exactly number of
> bytes of disk space reiserX filesystem allocates to store a file in
> filesystem because of rebalancing.
  Yes, I agree that accounting metadata is almost impossible. But still
I think it would be nice if especially compressed file would be
accounted only for its compressed size and not for the uncompressed
one. This is basically the only reason why I didn't yet decide to use
just the plain amount of file's data.

> For quota in reiser4 : we probably need to make it "transactional".
> Do you think we can make quota counter update in the same transaction
> with the quoted operation?
  Yes, that should be possible and not very complicated - ext3 and
reiser3 already support this. If the quota callbacks are set properly
then each call of DQUOT_ALLOC/FREE_... will end up as a call to
foofs_quota_write() to update data in the quota file and filesystem can
then attach this update to the running transaction - at least this way
it works for ext3 and reiser3.

								Honza