On Fri, Sep 14, 2012 at 08:08:48PM +0200, Michal Mazurek wrote:
> Taken from FreeBSD.
>
>
> Index: Makefile
> ===================================================================
> RCS file: /cvs/src/share/man/man9/Makefile,v
> retrieving revision 1.171
> diff -u -p -r1.171 Makefile
> --- Makefile 21 Jun 2012 18:02:21 -0000 1.171
> +++ Makefile 14 Sep 2012 18:06:46 -0000
> @@ -373,5 +373,6 @@ MLINKS+=VOP_LOOKUP.9 VOP_ABORTOP.9 VOP_L
> MLINKS+=workq_add_task.9 workq_create.9 \
> workq_add_task.9 workq_queue_task.9 \
> workq_add_task.9 workq_destroy.9
> +MLINKS+=vhold.9 vdrop.9
>
> .include <bsd.prog.mk>
> Index: vhold.9
> ===================================================================
> RCS file: /cvs/src/share/man/man9/vhold.9,v
> retrieving revision 1.6
> diff -u -p -r1.6 vhold.9
> --- vhold.9 15 Dec 2009 07:34:58 -0000 1.6
> +++ vhold.9 14 Sep 2012 18:06:46 -0000
> @@ -38,6 +38,8 @@
> .Fd #include <sys/vnode.h>
> .Ft void
> .Fn vhold "struct vnode *vp"
> +.Ft void
> +.Fn vdrop "struct vnode *vp"
> .Sh DESCRIPTION
> The
> .Fn vhold
> @@ -50,6 +52,16 @@ and
> .Va v_usecount
> are both zero, it will be removed from the free list and
> added to the vnode hold list.
> +.Pp
> +The
> +.Fn vdrop
> +function decrements the
> +.Va v_holdcnt
> +of the vnode.
> +If the holdcount is less than or equal to zero prior to calling
> +.Fn vdrop ,
> +the system will panic.
> +If the vnode is no longer referenced, it will be freed.
> .Sh SEE ALSO
> .Xr vnode 9
> .Sh AUTHORS
>
in vfs_subr.c (bear with me ;) it has:
/* Lose interest in a vnode. */
void
vdrop(struct vnode *vp)
{
#ifdef DIAGNOSTIC
if (vp->v_holdcnt == 0)
panic("vdrop: zero holdcnt");
#endif
vp->v_holdcnt--;
the text pasted is:
If the holdcount is less than or equal to zero
prior to calling vdrop...
doesn;t the code mean the check is for zero, not "less than or equal to
zero"?
jmc
