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<p class=MsoPlainText>Thanks Deepak, one more question:<o:p></o:p></p>
<p class=MsoPlainText><o:p> </o:p></p>
<p class=MsoPlainText>Can we export a FUSE mounted volume (on gluster client)
to be a NAS backend ? <o:p></o:p></p>
<p class=MsoPlainText>thus the client can act as a NAS server with file
distribution capability.<o:p></o:p></p>
<p class=MsoNormal><span style='font-size:11.0pt;color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;color:#1F497D'>Bill<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;color:#1F497D'><o:p> </o:p></span></p>
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<p class=MsoNormal align=left style='text-align:left'><b><span lang=ZH-CN
style='font-size:10.0pt;font-family:"SimSun","serif";color:windowtext'>发件人</span></b><b><span
style='font-size:10.0pt;font-family:"SimSun","serif";color:windowtext'>:</span></b><span
style='font-size:10.0pt;font-family:"SimSun","serif";color:windowtext'> Deepak
C Shetty [mailto:deepakcs@linux.vnet.ibm.com] <br>
<b><span lang=ZH-CN>发送时间</span>:</b> Wednesday, March 14, 2012 11:44 PM<br>
<b><span lang=ZH-CN>收件人</span>:</b> Bill Bao<br>
<b><span lang=ZH-CN>抄送</span>:</b> gluster-users@gluster.org<br>
<b><span lang=ZH-CN>主题</span>:</b> Re: [Gluster-users] does Gluster support
O_DIRECT ?<o:p></o:p></span></p>
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<p class=MsoNormal align=left style='text-align:left'><o:p> </o:p></p>
<p class=MsoNormal>On 03/14/2012 07:29 AM, Bill Bao wrote: <o:p></o:p></p>
<p class=MsoNormal>This might be a question asked before, but I just couldn’t
effectively search the whole archives,<o:p></o:p></p>
<p class=MsoNormal>So please bear me and kindly advise.<o:p></o:p></p>
<p class=MsoNormal> <o:p></o:p></p>
<p class=MsoNormal>We have a 3<sup>rd</sup> party application (video streaming
kind of) which uses directIO (O_DIRECT).<o:p></o:p></p>
<p class=MsoNormal>On the server side, in the posix translator, we added the “<span
style='font-size:12.0pt;font-family:"SimSun","serif"'>option o-direct enable<span
lang=ZH-CN>”</span></span><span lang=ZH-CN> </span><o:p></o:p></p>
<p class=MsoNormal>On the client side, we mounted as “mount -t glusterfs -o
direct-io-mode=enable server1:/test-volume /mnt/glusterfs”<o:p></o:p></p>
<p class=MsoNormal> <o:p></o:p></p>
<p class=MsoNormal>But the application still fails with error (cannot
create/open file with O_DIRECT).<o:p></o:p></p>
<p class=MsoNormal> <o:p></o:p></p>
<p class=MsoNormal>Then we trace to the fuse module in the kernel, which has
following checking:<o:p></o:p></p>
<p class=MsoNormal> <o:p></o:p></p>
<p class=MsoNormal align=left style='text-align:left'><span style='font-size:
10.0pt;font-family:"Verdana","sans-serif"'>int fuse_open_common(struct inode *inode, struct file *file, bool isdir)</span><o:p></o:p></p>
<p class=MsoNormal align=left style='text-align:left'><span style='font-size:
10.0pt;font-family:"Verdana","sans-serif"'>{</span><o:p></o:p></p>
<p class=MsoNormal align=left style='text-align:left'><span style='font-size:
10.0pt;font-family:"Verdana","sans-serif"'> struct fuse_conn *fc = get_fuse_conn(inode);</span><o:p></o:p></p>
<p class=MsoNormal align=left style='text-align:left'><span style='font-size:
10.0pt;font-family:"Verdana","sans-serif"'> int err;</span><o:p></o:p></p>
<p class=MsoNormal align=left style='text-align:left'><span style='font-size:
10.0pt;font-family:"Verdana","sans-serif"'> /* VFS checks this, but only _after_ ->open() */</span><o:p></o:p></p>
<p class=MsoNormal align=left style='text-align:left'><span style='font-size:
10.0pt;font-family:"Verdana","sans-serif";color:red'> <strong><span
style='font-family:"Verdana","sans-serif"'> if (file->f_flags & O_DIRECT)</span></strong></span><o:p></o:p></p>
<p class=MsoNormal align=left style='text-align:left'><strong><span
style='font-size:10.0pt;font-family:"Verdana","sans-serif";color:red'> return -EINVAL;</span></strong><o:p></o:p></p>
<p class=MsoNormal align=left style='text-align:left'><span style='font-size:
10.0pt;font-family:"Verdana","sans-serif"'> err = generic_file_open(inode, file);</span><o:p></o:p></p>
<p class=MsoNormal> <o:p></o:p></p>
<p class=MsoNormal>looks like regardless what we configure on the gluster side,
the FUSE still rejects the O_DIRECT.<o:p></o:p></p>
<p class=MsoNormal>Could someone shed light ? we’re also trying to take out the
O_DIRECT checking in FUSE module,<o:p></o:p></p>
<p class=MsoNormal>to see what will happen, will report soon.<o:p></o:p></p>
<p class=MsoNormal> <o:p></o:p></p>
<p class=MsoNormal>Bill Bao<o:p></o:p></p>
<p class=MsoNormal> <o:p></o:p></p>
<p class=MsoNormal align=left style='text-align:left'><span style='font-size:
12.0pt;font-family:"Times New Roman","serif"'>O_DIRECT support for fuse was
added recently. Check the fsdevel archives.<br>
<br>
<o:p></o:p></span></p>
<p class=MsoNormal> <o:p></o:p></p>
<p class=MsoNormal> <o:p></o:p></p>
<p class=MsoNormal> <o:p></o:p></p>
<p class=MsoNormal> <o:p></o:p></p>
<pre><o:p> </o:p></pre><pre><o:p> </o:p></pre><pre>_______________________________________________<o:p></o:p></pre><pre>Gluster-users mailing list<o:p></o:p></pre><pre><a
href="mailto:Gluster-users@gluster.org">Gluster-users@gluster.org</a><o:p></o:p></pre><pre><a
href="http://gluster.org/cgi-bin/mailman/listinfo/gluster-users">http://gluster.org/cgi-bin/mailman/listinfo/gluster-users</a><o:p></o:p></pre>
<p class=MsoNormal align=left style='text-align:left'><span style='font-size:
12.0pt;font-family:"Times New Roman","serif"'><o:p> </o:p></span></p>
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