Re: REVIEW: Fix for incore extent corruption.

[Lachlan McIlroy <lachlan@xxxxxxx>]

Eric Sandeen wrote:
> Lachlan McIlroy wrote:
> > Here's a patch to remove xfs_iext_irec_compact_full() like Russell
> > did in his original patch - are you guys happy with this?
> >
> > I'm putting it through it's paces now and so far it looks good.
> I'll have to think more about it, honestly.  Probably fine, but I've not
> looked at all the surrounding code, I was so far just looking for the
> original bug.
>
> (FWIW, compact_full *does* get called reasonably frequently, but the
> memmove case is what's hard to hit...)
xfs_iext_irec_compact_full() is probably getting called frequently from
xfs_iext_indirect_to_direct() which we only ever call when the number of
extents will fit into one extent buffer so we will never need the memmove
case in xfs_iext_irec_compact_full() and we can safely call
xfs_iext_irec_compact_pages() instead.

I wonder why xfs_iext_irec_compact_pages() is doing a memmove() instead
of a memcpy().

> -Eric
>
> > --- a/fs/xfs/xfs_inode.c        2008-09-19 13:08:08.000000000 +1000
> > +++ b/fs/xfs/xfs_inode.c        2008-09-19 13:16:34.000000000 +1000
> > @@ -4157,7 +4166,7 @@ xfs_iext_indirect_to_direct(
> >         ASSERT(nextents <= XFS_LINEAR_EXTS);
> >         size = nextents * sizeof(xfs_bmbt_rec_t);
> >  
> > -	xfs_iext_irec_compact_full(ifp);
> > +       xfs_iext_irec_compact_pages(ifp);
> >         ASSERT(ifp->if_real_bytes == XFS_IEXT_BUFSZ);
> >  
> >  	ep = ifp->if_u1.if_ext_irec->er_extbuf;
> ...