[CFT] libzfs_core for 9-STABLE

[John Theus]

>Hello all,
>
>libzfs_core and the rewritten locking code around dsl_sync_dataset
>have been commited to -HEAD:
>http://svnweb.freebsd.org/changeset/base/248571
>
>The scheduled merge date to 9-STABLE is around Apr 21, 2013.
>
>Early adopters can test new code by applying the following patch
>(against stable/9 r248611):
>http://people.freebsd.org/~mm/patches/zfs/stable-9-248611-lzc.patch.gz
>
>Steps to apply to a clean checked-out source:
>cd /path/to/src
>patch -p0 < /path/to/stable-9-248611-lzc.patch
>
>Alternatively you can download a pre-compiled amd64 mfsBSD image for testing:
>(see http://mfsbsd.vx.sk for more information on mfsBSD)
>http://mfsbsd.vx.sk/files/testing/
>
>I am primarily interested in the following areas of feedback:
>- stability
>- backward compatibility (new kernel, old utilities)
>
>Feedback and suggestions are welcome.
>
>-- 
>Martin Matuska
>FreeBSD committer
>http://blog.vx.sk

I upgraded both kernel and world on a machine that was running 9.1-STABLE
r248385 to the above:
9.1-STABLE #1 r248619M: Mon Mar 25 14:16:45 PDT 2013

This machine is used for zfs send/recv backups and it has been stable since the
upgrade.

By a chance typo, I found a problem in zfs release which doesn't exist on an
unpatched machine. To reproduce just do the following:

# zfs hold test filesystem at snap
# zfs release test filesystem at snap1   # snap1 does not exist
# (no error message produced)

# zfs release test filesystem at snap
# zfs release test filesystem at snap
internal error: No such process
[1]    857 abort      zfs release test
#

John Theus
TheUsGroup.com