<div dir="ltr"><div class="gmail_extra"><div class="gmail_quote">On Wed, Apr 20, 2016 at 6:24 PM, manty kuma <span dir="ltr"><<a href="mailto:mantykuma@gmail.com" target="_blank">mantykuma@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex"><div dir="ltr"><div><div><div><div>Hi,<br><br></div>I am looking into an issue where unmounting /data is failing.<br></div>I receive -EBUSY as the sum off all mnt_count(mnt->mnt_pcp->mnt_count) of all cpu's > 2 (the value in my case is 3).<br><br></div><div>I am debugging from linux crash dump.<br>Is there any way that I can know the owners/responsible drivers that have incereased this refcount and left it like that without decrementing?<br><br><br></div><div>Kindly share any helpful information. Thank you.<br></div><div><br></div>Best Regards,<br></div>Manty<br></div>
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<br></blockquote></div><br></div><div class="gmail_extra"><br></div><div class="gmail_extra"><br></div><div class="gmail_extra"><div class="gmail_extra">Hi Manty,</div><div class="gmail_extra"><br></div><div class="gmail_extra"><br></div><div class="gmail_extra">UMOUNT returns -EBUSY in many cases.</div><div class="gmail_extra">Following points you may consider to debug your issue:</div><div class="gmail_extra"><br></div><div class="gmail_extra">1. Check any file is open or mount point is in used by</div><div class="gmail_extra"> 1. lsof | grep <mount_path></div><div class="gmail_extra"> 2. fuser -m <mount_path></div><div class="gmail_extra"> 3. you cd into mount path directory</div><div class="gmail_extra">2. If there are no files open or mount point is not actually busy then</div><div class="gmail_extra"> - Track the dentry count & mount counts</div><div class="gmail_extra"> - fget, dget, mntget and fput, dput, mntput verify any leakage happened.</div><div class="gmail_extra"> You have to add printk statements in all such locations and whether they really increment or decrement dentry or mnt counts.</div><div class="gmail_extra">3. Please provide the more details,</div><div class="gmail_extra"> - Are you using automount or normal mount ?</div><div class="gmail_extra"> - Which operation you perform inside mount and the steps to reproduce the problem.</div><div class="gmail_extra">4. I recently worked on similar problem that automount give EBUSY error on umount and</div><div class="gmail_extra"> the the root cause I found is : Implementation of fput changes from 3.6.x kernel.</div><div class="gmail_extra"> They added deffered working and perform fput operation asynchronously.</div><div class="gmail_extra"> which causes immediate umount fails on automount.</div><div class="gmail_extra"><br></div><div class="gmail_extra">Hope so this will help you to debug your problem.</div><div class="gmail_extra"> </div><div class="gmail_extra"><br></div><div class="gmail_extra">Thanks & Regards,</div><div class="gmail_extra"> PraviN</div></div></div>