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<samba:parameter name= "level2 oplocks"
context="S"
type="boolean"
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xmlns:samba="http://www.samba.org/samba/DTD/samba-doc">
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<description >
<para > This parameter controls whether Samba supports
level2 (read-only) oplocks on a share.</para>
<para > Level2, or read-only oplocks allow Windows NT clients
that have an oplock on a file to downgrade from a read-write oplock
to a read-only oplock once a second client opens the file (instead
of releasing all oplocks on a second open, as in traditional,
exclusive oplocks). This allows all openers of the file that
support level2 oplocks to cache the file for read-ahead only (ie.
they may not cache writes or lock requests) and increases performance
for many accesses of files that are not commonly written (such as
application .EXE files).</para>
<para > Once one of the clients which have a read-only oplock
writes to the file all clients are notified (no reply is needed
or waited for) and told to break their oplocks to " none" and
delete any read-ahead caches.</para>
<para > It is recommended that this parameter be turned on to
speed access to shared executables.</para>
<para > For more discussions on level2 oplocks see the CIFS spec.</para>
<para > Currently, if <link linkend= "KERNELOPLOCKS" > <parameter moreinfo= "none" > kernel
oplocks</parameter> </link> are supported then level2 oplocks are
not granted (even if this parameter is set to <constant > yes</constant> ).
Note also, the <link linkend= "OPLOCKS" > <parameter moreinfo= "none" > oplocks</parameter>
</link> parameter must be set to <constant > yes</constant> on this share in order for
this parameter to have any effect.</para>
</description>
<related > oplocks</related>
<related > kernel oplocks</related>
<value type= "default" > yes</value>
</samba:parameter>
