[2.6 patch] include/linux/nfsd/nfsfh.h:fh_unlock(): change an error to a BUG_ON()

Adrian Bunk
2006-11-12T17:48:28Z

On Sun, Nov 12, 2006 at 10:58:47AM -0500, Trond Myklebust wrote:
> On Sun, 2006-11-12 at 14:17 +0100, Adrian Bunk wrote:
> > dereference
> > Reply-To:
> > Fcc: =sent-mail
> >
> > When we know fhp->fh_dentry is NULL, a code path where it's being
> > dereferenced isn't a good choice.
> >
> > Spotted by the coverity checker.
> >
> > Signed-off-by: Adrian Bunk <bunk@stusta.de>
> >
> > --- linux-2.6/include/linux/nfsd/nfsfh.h.old 2006-11-12 14:13:34.000000000 +0100
> > +++ linux-2.6/include/linux/nfsd/nfsfh.h 2006-11-12 14:13:49.000000000 +0100
> > @@ -330,8 +330,7 @@ fh_unlock(struct svc_fh *fhp)
> > {
> > if (!fhp->fh_dentry)
> > printk(KERN_ERR "fh_unlock: fh not verified!\n");
> > -
> > - if (fhp->fh_locked) {
> > + else if (fhp->fh_locked) {
> > fill_post_wcc(fhp);
> > mutex_unlock(&fhp->fh_dentry->d_inode->i_mutex);
> > fhp->fh_locked = 0;
> >
>
> This issue has come up on lkml before. Please just convert that check
> for fhp->fh_dentry into a BUG_ON().

Patch below.

> Trond

cu
Adrian

<-- snip -->

!fhp->fh_dentry is a condition that mustn't ever happen (and we might
run into additional trouble later).

Signed-off-by: Adrian Bunk <bunk@stusta.de>

--- linux-2.6/include/linux/nfsd/nfsfh.h.old 2006-11-12 18:37:43.000000000 +0100
+++ linux-2.6/include/linux/nfsd/nfsfh.h 2006-11-12 18:38:03.000000000 +0100
@@ -328,8 +328,7 @@
static inline void
fh_unlock(struct svc_fh *fhp)
{
- if (!fhp->fh_dentry)
- printk(KERN_ERR "fh_unlock: fh not verified!\n");
+ BUG_ON(!fhp->fh_dentry);

if (fhp->fh_locked) {