Re: [Squashfs-devel] squashfs xattr support?

[Helge B. <hel...@se...>]

Am Tuesday 20 April 2010 11:57:18 schrieb Phillip Lougher:
> Stephen Hemminger wrote:
> > Vyatta uses squashfs both for livecd and installed image mode, and in
> > order to support SELinux properly we need xattr supported on squashfs.
> >
> > I know the current version of squashfs doesn't support xattr, and there
> > are hints of future support. But we need it sooner, does anybody have a
> > "back of the envelope" description of how they expect it to work
> > (data formats etc), I am perfectly willing to fill in the missing code.
>
> I implemented most of the xattr support for Squashfs 4.0 in 2008, but
> abandoned it to concentrate on getting Squashfs mainlined for 2.6.29.
> The xattr file system format was defined and I had initial xattr support
> in mksquashfs.  The major thing missing was kernel code...   Rather than
> go through a fourth or fifth kernel code review process (the non-xattr
> kernel code had successfully gone through three kernel reviews),
> I submitted the non-xattr code for 2.6.29 and it was accepted.
>
> I can dig out the code and finish it off, looking at Helge's kernel patch
> there's less work to do in the kernel than I anticipated.  Unfortunately
> since mainlining no-one's asked for xattr support and consequently it's
> been of less priority to finish than working on paid Squashfs work
> (adding additional compression formats).

There is a little bit more to do than what I did in the patch to properly 
filter xattrs according to their designation (I know what to do but it will 
take another day or so).

Maybe you could provide a short description of how you had originally envisaged 
the xattr storage format to look like? (I may have missed your reply to a 
similar request back in march, so I simply assumed you did not have any plans 
for that yet and simply went along). There is certainly no problem in one of 
us lending a helping hand to you in quickly filling in any missing pieces of 
implementation.

Best regards
Helge
-- 
Dr.-Ing.
Helge Bahmann
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