kern/161968: [zfs] [hang] renaming snapshot with -r including a zvol snapshot causes total ZFS freeze/lockup

[Richard Yao]

The following reply was made to PR kern/161968; it has been noted by GNATS.

From: Richard Yao <ryao at gentoo.org>
To: bug-followup at FreeBSD.org
Cc: peter.maloney at brockmann-consult.de
Subject: Re: kern/161968: [zfs] [hang] renaming snapshot with -r including
 a zvol snapshot causes total ZFS freeze/lockup
Date: Wed, 13 Jun 2012 14:17:33 -0400

 I tried to reproduce this issue after being contacted about it by Peter
 on freenode. I had to modify his script to destroy datasets
 individually, instead of recursively by running the following command:
 
 for i in $(zfs list -t snapshot -H -o name | grep
 testcrashsnap${current}); do zfs destroy $i; done;
 
 Otherwise, a "dataset is busy" failure occurs. This occurs on both
 FreeBSD and Linux.
 
 After doing that (and changing dataset=big to dataset=rpool), I was able
 to test his script in virtual machines running Gentoo FreeBSD 9-RELEASE
 and Gentoo Linux. I reproduced this issue on Gentoo FreeBSD 9.0-RELEASE.
 On the other hand, Gentoo Linux successfully completed 6570 iterations.
 This was with the ZFSOnLinux kernel modules. The code is available on
 github:
 
 https://github.com/zfsonlinux/zfs
 
 The actual code that I used to test was a patched version that I develop
 in a separate branch. You can find it here:
 
 https://github.com/ryao/zfs/tree/gentoo
 
 My current focus is on ZFS support in Gentoo Linux, but I would be happy
 to help my FreeBSD counterparts troubleshoot this. Please do not
 hesitate to contact me with questions.