VREF(9)                FreeBSD Kernel Developer's Manual               VREF(9)

NAME
     vref, vrefl - increment the use count for a vnode

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

     void
     vref(struct vnode *vp);

     void
     vrefl(struct vnode *vp);

DESCRIPTION
     Increment the v_usecount field of a vnode.

     vp  the vnode to increment

     Each vnode maintains a reference count of how many parts of the system
     are using the vnode.  This allows the system to detect when a vnode is no
     longer being used and can be safely recycled for a different file.

     Any code in the system which is using a vnode (e.g. during the operation
     of some algorithm or to store in a data structure) should call vref() or
     vrefl().

     vref() locks the vnode interlock while vrefl() expects the interlock to
     already be held.

SEE ALSO
     vget(9), vnode(9), vput(9), vrefcnt(9), vrele(9)

AUTHORS
     This manual page was written by Doug Rabson.

FreeBSD 13.1-RELEASE-p6        January 18, 2016        FreeBSD 13.1-RELEASE-p6