Re: d_splice_alias() problem.

Greg Banks
2004-05-04T00:07:37Z

On Tue, May 04, 2004 at 09:28:48AM +1000, Neil Brown wrote:
> On Monday May 3, gnb@melbourne.sgi.com wrote:
> > Neil Brown wrote:
> > >
> > * Dentry_stat.nr_unused can be be spuriously decremented when dput()
> > races with __dget_unlocked(). Eventual result is nr_unused<0
> > and kswapd loops. This is the problem I mentioned earlier. Note
> > that this is not an NFS-specific problem. Fix is:
> >
> > --- linux.orig/fs/dcache.c Mon May 3 21:46:30 2004
> > +++ linux/fs/dcache.c Mon May 3 21:49:07 2004
> > @@ -255,8 +255,8 @@
> >
> > static inline struct dentry * __dget_locked(struct dentry *dentry)
> > {
> > - atomic_inc(&dentry->d_count);
> > - if (atomic_read(&dentry->d_count) == 1) {
> > + if (atomic_inc(&dentry->d_count) == 1) {
>
> One problem with this is that (in include/asm-i386/atomic.h at least):
> static __inline__ void atomic_inc(atomic_t *v)
>
> atomic_inc returns "void".

Doh! This is what comes from doing all coding and testing on minority
achitectures...I'll think about this a bit more.

Greg.
--
Greg Banks, R&D Software Engineer, SGI Australian Software Group.
I don't speak for SGI.