<html xmlns:o="urn:schemas-microsoft-com:office:office" xmlns:w="urn:schemas-microsoft-com:office:word" xmlns:m="http://schemas.microsoft.com/office/2004/12/omml" xmlns="http://www.w3.org/TR/REC-html40"><head><meta http-equiv=Content-Type content="text/html; charset=utf-8"><meta name=Generator content="Microsoft Word 15 (filtered medium)"><style><!--
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--></style></head><body lang=EN-US link=blue vlink="#954F72"><div class=WordSection1><p class=MsoNormal>Hi Zdenek,</p><p class=MsoNormal>Thank you for the acknowledging the issue.</p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>I may not be at a liberty to choose the environment always, as most of the major distributions come bundled with 2.02.133</p><p class=MsoNormal>I have two followup questions.</p><p class=MsoNormal>1/ Is there a way to tell that a particular version has very critical bug (like the one I reported)? Nothing short of hitting it seem the way to confirm currently.</p><p class=MsoNormal>2/ which is the nearest stable release that addresses this particular issue?</p><p class=MsoNormal>3/ Does latest lvm stable work well in old distributions, Linux kernels too? Whats the compatibility matrix here? </p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Regards</p><p class=MsoNormal>LN</p><p class=MsoNormal><o:p> </o:p></p><div style='mso-element:para-border-div;border:none;border-top:solid #E1E1E1 1.0pt;padding:3.0pt 0in 0in 0in'><p class=MsoNormal style='border:none;padding:0in'><b>From: </b><a href="mailto:zkabelac@redhat.com">Zdenek Kabelac</a><br><b>Sent: </b>Tuesday, July 30, 2019 1:51 PM<br><b>To: </b><a href="mailto:lvm-devel@redhat.com">LVM2 development</a>; <a href="mailto:lns@portworx.com">Lakshmi Narasimhan Sundararajan</a><br><b>Subject: </b>Re: [lvm-devel] lvmcache in writeback mode gets stuck flushing dirtyblocks</p></div><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Dne 30. 07. 19 v 6:58 Lakshmi Narasimhan Sundararajan napsal(a):</p><p class=MsoNormal>> Hi Team,</p><p class=MsoNormal>> </p><p class=MsoNormal>> A very good day to all.</p><p class=MsoNormal>> </p><p class=MsoNormal>> </p><p class=MsoNormal>> I am using lvmcache in writeback mode. When there are dirty blocks still in </p><p class=MsoNormal>> the lv, and if needs to be destroyed or flushed, then</p><p class=MsoNormal>> </p><p class=MsoNormal>> It seems to me that there are some conditions under which the dirty data flush </p><p class=MsoNormal>> gets stuck forever.</p><p class=MsoNormal>> </p><p class=MsoNormal>> As an example:</p><p class=MsoNormal>> </p><p class=MsoNormal>> root@pdc4-sm35:~# lvremove -f pwx0/pool</p><p class=MsoNormal>> </p><p class=MsoNormal>> 367 blocks must still be flushed.</p><p class=MsoNormal>> </p><p class=MsoNormal>> 367 blocks must still be flushed.</p><p class=MsoNormal>> </p><p class=MsoNormal>> 367 blocks must still be flushed.</p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>> I am running these version:</p><p class=MsoNormal>> </p><p class=MsoNormal>> root@pdc4-sm35:~# lvm version</p><p class=MsoNormal>> </p><p class=MsoNormal>> LVM version: 2.02.133(2) (2015-10-30)</p><p class=MsoNormal>> </p><p class=MsoNormal>> I filed one here myself, https://github.com/lvmteam/lvm2/issues/22, trying to </p><p class=MsoNormal>> understand from you experts where we are on this?</p><p class=MsoNormal>> </p><p class=MsoNormal>> I would sincerely appreciate your help in understanding the state of this </p><p class=MsoNormal>> issue in more detail.</p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Hi</p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Yep you are using very old version of lvm2 - there is already year 2019 - and </p><p class=MsoNormal>in the initial releases of lvm2 with writeback cache support (as you happen to </p><p class=MsoNormal>still use these days) there was a problem that uncaching was not switching to </p><p class=MsoNormal>writethrough mode (and this was not the only one)</p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Please consider to use way newer lvm2 & kernel.</p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Regards</p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Zdenek</p><p class=MsoNormal><o:p> </o:p></p></div></body></html>