<table><tr><td style="">bruns added a comment.
</td><a style="text-decoration: none; padding: 4px 8px; margin: 0 8px 8px; float: right; color: #464C5C; font-weight: bold; border-radius: 3px; background-color: #F7F7F9; background-image: linear-gradient(to bottom,#fff,#f1f0f1); display: inline-block; border: 1px solid rgba(71,87,120,.2);" href="https://phabricator.kde.org/D17737">View Revision</a></tr></table><br /><div><div><p>I think it would be much simpler if you just tried to do the the FICLONE iotctl in the job, without any prior checking:</p>
<ul class="remarkup-list">
<li class="remarkup-list-item">no possibility for races</li>
<li class="remarkup-list-item">less syscals</li>
<li class="remarkup-list-item">less code</li>
</ul></div></div><br /><div><strong>INLINE COMMENTS</strong><div><div style="margin: 6px 0 12px 0;"><div style="border: 1px solid #C7CCD9; border-radius: 3px;"><div style="padding: 0; background: #F7F7F7; border-color: #e3e4e8; border-style: solid; border-width: 0 0 1px 0; margin: 0;"><div style="color: #74777d; background: #eff2f4; padding: 6px 8px; overflow: hidden;"><a style="float: right; text-decoration: none;" href="https://phabricator.kde.org/D17737#inline-97540">View Inline</a><span style="color: #4b4d51; font-weight: bold;">copyjob.cpp:742</span></div>
<div style="font: 11px/15px "Menlo", "Consolas", "Monaco", monospace; white-space: pre-wrap; clear: both; padding: 4px 0; margin: 0;"><div style="padding: 0 8px; margin: 0 4px; background: rgba(151, 234, 151, .6);"> <span style="color: #aa4000">if</span> <span class="p">(</span><span style="color: #aa2211">!</span><span class="n">isDir</span> <span style="color: #aa2211">&&</span> <span class="n">info</span><span class="p">.</span><span class="n">linkDest</span><span class="p">.</span><span class="n">isEmpty</span><span class="p">()</span> <span style="color: #aa2211">&&</span> <span class="n">m_mode</span> <span style="color: #aa2211">==</span> <span class="n">CopyJob</span><span style="color: #aa2211">::</span><span class="n">Copy</span> <span style="color: #aa2211">&&</span> <span class="n">m_bDestSupportsCoW</span><span class="p">)</span> <span class="p">{</span>
</div><div style="padding: 0 8px; margin: 0 4px; background: rgba(151, 234, 151, .6);"> <span style="color: #aa4000">const</span> <span class="n">QString</span> <span class="n">srcDevice</span> <span style="color: #aa2211">=</span> <span class="n">KMountPoint</span><span style="color: #aa2211">::</span><span class="n">currentMountPoints</span><span class="p">().</span><span class="n">findByPath</span><span class="p">(</span><span class="n">info</span><span class="p">.</span><span class="n">uSource</span><span class="p">.</span><span class="n">toLocalFile</span><span class="p">())</span><span style="color: #aa2211">-></span><span class="n">mountedFrom</span><span class="p">();</span>
</div><div style="padding: 0 8px; margin: 0 4px; background: rgba(151, 234, 151, .6);"> <span class="n">info</span><span class="p">.</span><span class="n">bCreateClone</span> <span style="color: #aa2211">=</span> <span class="p">(</span><span class="n">srcDevice</span> <span style="color: #aa2211">==</span> <span class="n">m_destDevice</span><span class="p">);</span>
</div></div></div>
<div style="margin: 8px 0; padding: 0 12px;"><p style="padding: 0; margin: 8px;">it is *much* cheaper to compare the st_dev fields from stat for the source file and the destination directory.</p></div></div><br /><div style="border: 1px solid #C7CCD9; border-radius: 3px;"><div style="padding: 0; background: #F7F7F7; border-color: #e3e4e8; border-style: solid; border-width: 0 0 1px 0; margin: 0;"><div style="color: #74777d; background: #eff2f4; padding: 6px 8px; overflow: hidden;"><a style="float: right; text-decoration: none;" href="https://phabricator.kde.org/D17737#inline-97542">View Inline</a><span style="color: #4b4d51; font-weight: bold;">kmountpoint.cpp:471</span></div>
<div style="font: 11px/15px "Menlo", "Consolas", "Monaco", monospace; white-space: pre-wrap; clear: both; padding: 4px 0; margin: 0;"><div style="padding: 0 8px; margin: 0 4px; "> <span style="color: #aa2211">||</span> <span class="n">d</span><span style="color: #aa2211">-></span><span class="n">mountType</span> <span style="color: #aa2211">==</span> <span class="n">QLatin1String</span><span class="p">(</span><span style="color: #766510">"smb-share"</span><span class="p">);</span>
</div><div style="padding: 0 8px; margin: 0 4px; background: rgba(151, 234, 151, .6);"> <span style="color: #aa4000">const</span> <span style="color: #aa4000">bool</span> <span class="n">isCoWSupported</span> <span style="color: #aa2211">=</span> <span class="n">d</span><span style="color: #aa2211">-></span><span class="n">mountType</span> <span style="color: #aa2211">==</span> <span class="n">QLatin1String</span><span class="p">(</span><span style="color: #766510">"btrfs"</span><span class="p">)</span> <span style="color: #aa2211">||</span> <span class="n">d</span><span style="color: #aa2211">-></span><span class="n">mountType</span> <span style="color: #aa2211">==</span> <span class="n">QLatin1String</span><span class="p">(</span><span style="color: #766510">"xfs"</span><span class="p">);</span>
</div></div></div>
<div style="margin: 8px 0; padding: 0 12px;"><p style="padding: 0; margin: 8px;">This is not correct, xfs <strong>may</strong> support reflinks, but it is a feature only recently added, and has to be enabled at file system creation time.</p></div></div><br /><div style="border: 1px solid #C7CCD9; border-radius: 3px;"><div style="padding: 0; background: #F7F7F7; border-color: #e3e4e8; border-style: solid; border-width: 0 0 1px 0; margin: 0;"><div style="color: #74777d; background: #eff2f4; padding: 6px 8px; overflow: hidden;"><a style="float: right; text-decoration: none;" href="https://phabricator.kde.org/D17737#inline-97541">View Inline</a><span style="color: #4b4d51; font-weight: bold;">kmountpoint.h:145</span></div>
<div style="font: 11px/15px "Menlo", "Consolas", "Monaco", monospace; white-space: pre-wrap; clear: both; padding: 4px 0; margin: 0;"><div style="padding: 0 8px; margin: 0 4px; "><span style="color: #74777d"> * "foo" and "FOO" as being the same file (true for msdos systems)</span>
</div><div style="padding: 0 8px; margin: 0 4px; background: rgba(151, 234, 151, .6);"><span style="color: #74777d"> * @li SupportsCoW: returns true if the filesystem supports Copy-on-Write</span>
</div><div style="padding: 0 8px; margin: 0 4px; background: rgba(151, 234, 151, .6);"><span style="color: #74777d"> * (true for btrfs, xfs, etc.)</span>
</div></div></div>
<div style="margin: 8px 0; padding: 0 12px;"><p style="padding: 0; margin: 8px;">The correct term here is "reflink", not CoW.</p></div></div></div></div></div><br /><div><strong>REPOSITORY</strong><div><div>R241 KIO</div></div></div><br /><div><strong>REVISION DETAIL</strong><div><a href="https://phabricator.kde.org/D17737">https://phabricator.kde.org/D17737</a></div></div><br /><div><strong>To: </strong>chinmoyr, dfaure, davidedmundson<br /><strong>Cc: </strong>bruns, kde-frameworks-devel, michaelh, ngraham<br /></div>