Re: [-mm patch] fix unionfs compilation

Josef Sipek
2007-05-05T19:16:38Z

On Sat, May 05, 2007 at 11:57:18AM -0700, Andrew Morton wrote:
> On Sat, 5 May 2007 19:00:12 +0200 Adrian Bunk <bunk@stusta.de> wrote:
>
> > On Sat, May 05, 2007 at 01:49:55AM -0700, Andrew Morton wrote:
> > >...
> > > Changes since 2.6.21-rc7-mm2:
> > >...
> > > git-unionfs.patch
> > >...
> > > git trees
> > >...
> >
> > <-- snip -->
> >
> > ...
> > CC fs/unionfs/super.o
> > /home/bunk/linux/kernel-2.6/linux-2.6.21-mm1/fs/unionfs/super.c: In function ‘init_once’:
> > /home/bunk/linux/kernel-2.6/linux-2.6.21-mm1/fs/unionfs/super.c:822: error: ‘SLAB_CTOR_VERIFY’ undeclared (first use in this function)
> > /home/bunk/linux/kernel-2.6/linux-2.6.21-mm1/fs/unionfs/super.c:822: error: (Each undeclared identifier is reported only once
> > /home/bunk/linux/kernel-2.6/linux-2.6.21-mm1/fs/unionfs/super.c:822: error: for each function it appears in.)
> > make[3]: *** [fs/unionfs/super.o] Error 1
> >
> > <-- snip -->
> >
> > Signed-off-by: Adrian Bunk <bunk@stusta.de>
> >
> > ---
> > --- linux-2.6.21-mm1/fs/unionfs/super.c.old 2007-05-05 18:45:25.000000000 +0200
> > +++ linux-2.6.21-mm1/fs/unionfs/super.c 2007-05-05 18:46:03.000000000 +0200
> > @@ -819,8 +819,7 @@
> > {
> > struct unionfs_inode_info *i = v;
> >
> > - if ((flags & (SLAB_CTOR_VERIFY | SLAB_CTOR_CONSTRUCTOR)) ==
> > - SLAB_CTOR_CONSTRUCTOR)
> > + if (flags & SLAB_CTOR_CONSTRUCTOR)
> > inode_init_once(&i->vfs_inode);
> > }
>
> Bah, that was hidden from my allmodconfig because CONFIG_UNIONFS is inexplicably
> dependent upon CONFIG_SLAB.
>
> How come?

As it was discussed a while back on the mailing lists, Unionfs is trying to
be smart and tries to do reallocation on its own. The way it does it makes
it depend on some internals of the SLAB allocator. There have been some
patches out there for a realloc function (by Pekka Enberg, IIRC), but as far
as I can tell, they haven't been merged in.

Josef "Jeff" Sipek.

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