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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
     overhead.

     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.

     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 11.1-RELEASE-p4        February 24, 2016       FreeBSD 11.1-RELEASE-p4
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