1<html><head><meta http-equiv="Content-Type" content="text/html; charset=ANSI_X3.4-1968"><title>enum positive_aop_returns</title><meta name="generator" content="DocBook XSL Stylesheets V1.78.1"><link rel="home" href="index.html" title="Linux Filesystems API"><link rel="up" href="vfs.html#the_filesystem_types" title="The Filesystem types"><link rel="prev" href="vfs.html" title="Chapter&#160;1.&#160;The Linux VFS"><link rel="next" href="API-sb-end-write.html" title="sb_end_write"></head><body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center"><span class="phrase">enum positive_aop_returns</span></th></tr><tr><td width="20%" align="left"><a accesskey="p" href="vfs.html">Prev</a>&#160;</td><th width="60%" align="center">The Filesystem types</th><td width="20%" align="right">&#160;<a accesskey="n" href="API-sb-end-write.html">Next</a></td></tr></table><hr></div><div class="refentry"><a name="API-enum-positive-aop-returns"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>enum positive_aop_returns &#8212; 
2  aop return codes with specific semantics
3 </p></div><div class="refsynopsisdiv"><h2>Synopsis</h2><pre class="programlisting">
4enum positive_aop_returns {
5  AOP_WRITEPAGE_ACTIVATE,
6  AOP_TRUNCATED_PAGE
7};  </pre></div><div class="refsect1"><a name="idp1100345260"></a><h2>Constants</h2><div class="variablelist"><dl class="variablelist"><dt><span class="term">AOP_WRITEPAGE_ACTIVATE</span></dt><dd><p>
8Informs the caller that page writeback has
9completed, that the page is still locked, and
10should be considered active.  The VM uses this hint
11to return the page to the active list -- it won't
12be a candidate for writeback again in the near
13future.  Other callers must be careful to unlock
14the page if they get this return.  Returned by
15<code class="function">writepage</code>; 
16      </p></dd><dt><span class="term">AOP_TRUNCATED_PAGE</span></dt><dd><p>
17The AOP method that was handed a locked page has
18unlocked it and the page might have been truncated.
19The caller should back up to acquiring a new page and
20trying again.  The aop will be taking reasonable
21precautions not to livelock.  If the caller held a page
22reference, it should drop it before retrying.  Returned
23by <code class="function">readpage</code>.
24      </p></dd></dl></div></div><div class="refsect1"><a name="idp1101083700"></a><h2>Description</h2><p>
25   address_space_operation functions return these large constants to indicate
26   special semantics to the caller.  These are much larger than the bytes in a
27   page to allow for functions that return the number of bytes operated on in a
28   given page.
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