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<span style="font-weight:bold">From: </span><<a href="mailto:devel-bounces@openvz.org">devel-bounces@openvz.org</a>> on behalf of Kir Kolyshkin <<a href="mailto:kir@openvz.org">kir@openvz.org</a>><br>
<span style="font-weight:bold">Date: </span>Friday 15 April 2016 01:35<br>
<span style="font-weight:bold">To: </span>"<a href="mailto:devel@openvz.org">devel@openvz.org</a>" <<a href="mailto:devel@openvz.org">devel@openvz.org</a>><br>
<span style="font-weight:bold">Subject: </span>[Devel] O_NONBLOCK for directory<br>
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<div text="#000000" bgcolor="#FFFFFF">I am reviewing recent VZ7 libploop commits, in particular, this one:<br>
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<a class="moz-txt-link-freetext" href="https://src.openvz.org/projects/OVZ/repos/ploop/commits/36df847b9">
https://src.openvz.org/projects/OVZ/repos/ploop/commits/36df847b9</a><br>
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I left a question there, let me repeat it here in a hope someone answers.<br>
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<span class="changeset-author" title="Igor Sukhih" style="font-weight: bold; margin-right: 5px; color: rgb(51,
51, 51);">Igor Sukhih</span><span class="Apple-converted-space"> </span>committed<span class="Apple-converted-space"> </span><a class="changesetid" href="https://src.openvz.org/projects/OVZ/repos/ploop/commits/36df847b99c92557c69255ebfb00d4cc74cb51ac" data-changeset-id="36df847b99c92557c69255ebfb00d4cc74cb51ac" original-title="" style="color: rgb(59, 115, 175);
text-decoration: none; font-family: monospace; display:
inline-block; vertical-align: baseline; margin-left: 5px;">36df847b99c</a><time title="13 April 2016 05:04 PM" datetime="2016-04-13T17:04:27+0000" style="margin-left: 5px;
font-size: 12px; color: rgb(112, 112, 112);">Yesterday</time></div>
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<pre style="margin: 0px; padding: 0px; white-space: pre-wrap;">ploop_copy_init(): open folder with O_DIRECTORY flag
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...<br>
<blockquote type="cite"><tt>- _h->mntfd = open(mnt, O_RDONLY);</tt><tt><br>
</tt><tt>+</tt><tt> _h->mntfd = open(mnt, O_RDONLY|O_NONBLOCK|O_DIRECTORY);</tt><tt><br>
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1. What's the reason for adding O_NONBLOCK here? As far as I can see, it doesn't<br>
change anything at all (neither in this open(), nor in subsequent syncfs(), ioctl()<br>
and close())? I went as far as the kernel sources to check that O_NONBLOCK<br>
doesn't affect syncfs() call, but maybe I'm mistaken?</div>
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<div>Added accidentally, you are right, it doesn't change anything.</div>
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2. What's the reason for adding O_DIRECTORY? Ideally, the changelog<br>
should say why we're doing it, not what we do (as it's pretty clear<br>
from the patch itself).</div>
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<div>It does exactly as specified – enforces open file to be a directory. Any problems with this enforcement?</div>
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<div>Thank you,</div>
<div>Dmitry.</div>
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Regards,<br>
Kir.<br>
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