<?xml version='1.0'?>
-<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN" "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
+<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
+ "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
<!--
SPDX-License-Identifier: LGPL-2.1+
<listitem><para>Set file/directory attributes. Lines of this type
accept shell-style globs in place of normal path names.</para>
- <para>The format of the argument field is
- <varname>[+-=][aAcCdDeijsStTu] </varname>. The prefix
- <varname>+</varname> (the default one) causes the
- attribute(s) to be added; <varname>-</varname> causes the
- attribute(s) to be removed; <varname>=</varname> causes the
- attributes to be set exactly as the following letters. The
- letters <literal>aAcCdDeijsStTu</literal> select the new
- attributes for the files, see
- <citerefentry project='man-pages'><refentrytitle>chattr</refentrytitle>
+ <para>The format of the argument field is <varname>[+-=][aAcCdDeijPsStTu] </varname>. The prefix
+ <varname>+</varname> (the default one) causes the attribute(s) to be added; <varname>-</varname>
+ causes the attribute(s) to be removed; <varname>=</varname> causes the attributes to be set exactly
+ as the following letters. The letters <literal>aAcCdDeijPsStTu</literal> select the new attributes
+ for the files, see <citerefentry project='man-pages'><refentrytitle>chattr</refentrytitle>
<manvolnum>1</manvolnum></citerefentry> for further information.
</para>
<para>Passing only <varname>=</varname> as argument resets
</varlistentry>
</variablelist>
- <para>If the exclamation mark is used, this line is only safe of
+ <para>If the exclamation mark is used, this line is only safe to
execute during boot, and can break a running system. Lines
without the exclamation mark are presumed to be safe to execute
at any time, e.g. on package upgrades.
(ctime). Any of these three (or two) values will prevent cleanup
if it is more recent than the current time minus the age
field.</para>
+
+ <para>Note that while the aging algorithm is run a 'shared' BSD file lock (see <citerefentry
+ project='man-pages'><refentrytitle>flock</refentrytitle><manvolnum>2</manvolnum></citerefentry>) is
+ taken on each directory the algorithm descends into (and each directory below that, and so on). If the
+ aging algorithm finds a lock is already taken on some directory, it (and everything below it) is
+ skipped. Applications may use this to temporarily exclude certain directory subtrees from the aging
+ algorithm: the applications can take a BSD file lock themselves, and as long as they keep it aging of
+ the directory and everything below it is disabled.</para>
</refsect2>
<refsect2>