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<table class="head">
<tr>
<td class="head-ltitle">VRELE(9)</td>
<td class="head-vol">Kernel Developer's Manual</td>
<td class="head-rtitle">VRELE(9)</td>
</tr>
</table>
<div class="manual-text">
<section class="Sh">
<h1 class="Sh" id="NAME"><a class="permalink" href="#NAME">NAME</a></h1>
<p class="Pp"><code class="Nm">vput</code>, <code class="Nm">vrele</code>,
<code class="Nm">vunref</code> — <span class="Nd">decrement the use
count for a vnode</span></p>
</section>
<section class="Sh">
<h1 class="Sh" id="SYNOPSIS"><a class="permalink" href="#SYNOPSIS">SYNOPSIS</a></h1>
<p class="Pp"><code class="In">#include
<<a class="In">sys/param.h</a>></code>
<br/>
<code class="In">#include <<a class="In">sys/vnode.h</a>></code></p>
<p class="Pp"><var class="Ft">void</var>
<br/>
<code class="Fn">vput</code>(<var class="Fa" style="white-space: nowrap;">struct
vnode *vp</var>);</p>
<p class="Pp"><var class="Ft">void</var>
<br/>
<code class="Fn">vrele</code>(<var class="Fa" style="white-space: nowrap;">struct
vnode *vp</var>);</p>
<p class="Pp"><var class="Ft">void</var>
<br/>
<code class="Fn">vunref</code>(<var class="Fa" style="white-space: nowrap;">struct
vnode *vp</var>);</p>
</section>
<section class="Sh">
<h1 class="Sh" id="DESCRIPTION"><a class="permalink" href="#DESCRIPTION">DESCRIPTION</a></h1>
<p class="Pp">Decrement the <var class="Va">v_usecount</var> field of a
vnode.</p>
<dl class="Bl-tag">
<dt><var class="Fa">vp</var></dt>
<dd>the vnode to decrement</dd>
</dl>
<p class="Pp" id="vrele">The
<a class="permalink" href="#vrele"><code class="Fn">vrele</code></a>()
function takes an unlocked vnode and returns with the vnode unlocked.</p>
<p class="Pp" id="vput">The
<a class="permalink" href="#vput"><code class="Fn">vput</code></a>()
function should be given a locked vnode as argument, the vnode is unlocked
after the function returned. The <code class="Fn">vput</code>() is
operationally equivalent to calling <a class="Xr">VOP_UNLOCK(9)</a> followed
by <code class="Fn">vrele</code>(), with less overhead.</p>
<p class="Pp" id="vunref">The
<a class="permalink" href="#vunref"><code class="Fn">vunref</code></a>()
function takes a locked vnode as argument, and returns with the vnode
locked.</p>
<p class="Pp">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 <var class="Va">v_usecount</var> field of the non-doomed vnode reaches
zero, then it will be inactivated and placed on the free list.</p>
<p class="Pp" id="vrele~2">The
<a class="permalink" href="#vrele~2"><code class="Fn">vrele</code></a>()
function may lock the vnode. All three functions may sleep.</p>
<p class="Pp">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 <a class="Xr">vflush(9)</a>.</p>
</section>
<section class="Sh">
<h1 class="Sh" id="SEE_ALSO"><a class="permalink" href="#SEE_ALSO">SEE
ALSO</a></h1>
<p class="Pp"><a class="Xr">vget(9)</a>, <a class="Xr">vnode(9)</a>,
<a class="Xr">vref(9)</a>, <a class="Xr">vrefcnt(9)</a></p>
</section>
<section class="Sh">
<h1 class="Sh" id="AUTHORS"><a class="permalink" href="#AUTHORS">AUTHORS</a></h1>
<p class="Pp">This manual page was written by <span class="An">Doug
Rabson</span> and
<br/>
<span class="An">Konstantin Belousov</span>.</p>
</section>
</div>
<table class="foot">
<tr>
<td class="foot-date">February 24, 2016</td>
<td class="foot-os">FreeBSD 15.0</td>
</tr>
</table>
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