osx man page for vdrop

VHOLD(9)						   BSD Kernel Developer's Manual						  VHOLD(9)

NAME

     vhold, vdrop, vdropl -- acquire/release a hold on a vnode

SYNOPSIS

     #include <sys/param.h>
     #include <sys/vnode.h>

     void
     vhold(struct vnode *vp);

     void
     vholdl(struct vnode *vp);

     void
     vdrop(struct vnode *vp);

     void
     vdropl(struct vnode *vp);

DESCRIPTION

     The vhold() and vholdl() functions increment the v_holdcnt of the given vnode.  If the vnode has already been added to the free list and is
     still referenced, it will be removed.

     The vdrop() and vdropl() functions decrement the v_holdcnt of the vnode.  If the holdcount is less than or equal to zero prior to calling
     vdrop() or vdropl(), the system will panic.  If the vnode is no longer referenced, it will be freed.

     vhold() and vdrop() lock the vnode interlock while vholdl() and vdropl() expect the interlock to already be held.

SEE ALSO

     vnode(9)

AUTHORS

     This manual page was written by Chad David <davidc@acns.ab.ca>.

BSD
								   April 1, 2007							       BSD