Re: Strange NOTAIL inheritance behaviour in Reiserfs 3.6

["Michael Kerrisk" <mtk-lists@jambit.com>]

> On Thu, Jun 24, 2004 at 04:27:44PM +0200, Michael Kerrisk wrote:
> > >
> > > MK>     # mount -t reiserfs /dev/hda12 /testfs
> > > Does it work as expected if you add "-o attrs" to the mount command?
> > Yes!  Thanks.  However, it is a little unfortunate that if one fails
> > to use this option, then:
> > 1. "chattr +t" (and I suppose underlying ioctl()s) can still be used to
> >    set this attribute on a directory, without any error resulting.
> >    It would be better if an error is reported.
>
> Well, initial idea was to allow people to at least reset attributes
> in case of operationg with disabled attributes processing.

This seems to a bad idea.  Why should I be able to reset
attributes if the FS is mounted without "-o attrs"?  That
seems to thwart the point of excluding "-o attrs".  In any
case, how about at least an error when one tries to *set*
attributes when "-o attrs" was specified?

> > 2. The attribute is then inherited by files created in that directory,
> >    but has no effect.
>
> Yes, attribute inheritance is working. The only part that is disabled
> by default is copying from fs-specific attribute storage to actual VFS
inode
> attributes.
>
> > 3. A later explicit "chattr + t" on the files themselves DOES result in
> >    unpacking of the tails.  Why?
>
> There is a check in attributes setting code (and attributes
setting/cleaning
> is enabled), that tests if NOTAIL attribute is set, that calls tails
> unpacking if so. Next time you write to that file it will be packed back
> (if possible).

Strange ;-).

> I agree that all of this is not very intuitive, though.

Okay -- thanks Oleg.

Cheers,

Michael