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VRELE(9)		    Kernel Developer's Manual			VRELE(9)

NAME
     vput, vrele, vunref -- decrement the use count for a vnode

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

     void
     vput(struct vnode *vp);

     void
     vrele(struct vnode *vp);

     void
     vunref(struct vnode *vp);

DESCRIPTION
     Decrement the v_usecount field of a vnode.

     vp  the vnode to decrement

     The vrele() function takes an unlocked vnode and returns with the vnode un-
     locked.

     The  vput()  function should be given a locked vnode as argument, the vnode
     is unlocked after the  function  returned.   The  vput()  is  operationally
     equivalent  to  calling  VOP_UNLOCK(9) followed by vrele(), with less over-
     head.

     The vunref() function takes a locked vnode as argument,  and  returns  with
     the vnode locked.

     Any  code	in  the  system  which	signified its use of a vnode by usecount
     should call one of the listed function to decrement use  counter.	 If  the
     v_usecount  field of the non-doomed vnode reaches zero, then it will be in-
     activated and placed on the free list.

     The vrele() function may lock the vnode.  All three functions may sleep.

     The hold count for the vnode is always greater or equal  to  the  usecount.
     Non-forced  unmount  fails  when mount point owns a vnode that has non-zero
     usecount, see vflush(9).

SEE ALSO
     vget(9), vnode(9), vref(9), vrefcnt(9)

AUTHORS
     This manual page was written by Doug Rabson and
     Konstantin Belousov.

FreeBSD ports 15.quarterly	February 24, 2016			VRELE(9)

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