Unionfs patchset p19 commit?
Daichi GOTO
daichi at ongs.co.jp
Wed Sep 19 23:32:25 PDT 2007
Kurt Jaeger wrote:
> Hi!
>
>>>> I have a big hope to get merged into FreeBSD until
>>>> 7-RELEASE. Progress is step by step slowly, but going
>>>> forward absolutely. If you have interest in unionfs
>>>> improvements, push your passion to re@ and fs@ committers ;-)
>>> Did you have a chance to look into this ?
>>>
>>> http://lists.freebsd.org/pipermail/freebsd-stable/2007-June/035798.html
>
>> Already we have fixed above issue.
> [...]
>
> I'm compiling this patch on my test system right now.
>
> Another issue is userland support for unionfs, e.g. in fstat,
> as described on this page:
>
> http://c0mplx.org/src/fstat-unionfs-patch/
>
> Do you plan to analyse/investigate this topic ?
It looks like interesting. But your patch has a issues.
+ /* fprintf(stderr,"found upper vnode\n"); */
+ res = ufs_filestat(&upper, fsp);
and
+ /* fprintf(stderr,"found lower vnode\n"); */
+ res = ufs_filestat(&lower, fsp);
depend on UFS. It must treat both UFS and no UFS fs.
And I am not a maintainer of fstat(1). Please contact to
maintainer. Perhaps Ed Maste(emaste) is maintainer I suppose
from commit log.
> There's another topic if one uses unionfs in jail() setups: How to
> backup the files, and only those files that a different from
> the base ?
>
> If I traverse a mounted unionfs, how do I know where data is coming
> from, the lower mount or the higher mount ?
>
> If I can't tell the difference, I'll backup quite a lot of stuff
> multiple times.
>
> I've experimented a little and found no easy way to tell lower
> from upper unless I open the file (which sounds expensive).
> Have a look at http://c0mplx.org/src/isunionfs.c -- does this
> sound like a way to go ?
The isunionfs.c looks like interesting, too :) But your
program is not complete. 'below' option gives it non-correct
work. Addition it does not consider unionfs and nullfs
combibation or something like that. To check upper/lower
completely, you need the same way of your fstat(1) patch.
But your idea looks interesting :) Keep your concern of
unionfs. To get keep concern is very good for us!
--
Daichi GOTO, http://people.freebsd.org/~daichi
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