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VRELE(9)	       FreeBSD 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
     unlocked.

     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(9), 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
     inactivated and placed on the free	list.  Since the functions might need
     to	call VOPs for the vnode, the Giant mutex should	be conditionally
     locked around the call.

     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	9.3		       November	20, 2010		   FreeBSD 9.3

NAME | SYNOPSIS | DESCRIPTION | SEE ALSO | AUTHORS

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