Document the dedupditto pool property.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #1839
Handle concurrent snapshot automounts failing due to EBUSY.

In the current snapshot automount implementation, it is possible for
multiple mounts to attempted concurrently.  Only one of the mounts will
succeed and the other will fail.  The failed mounts will cause an EREMOTE
to be propagated back to the application.

This commit works around the problem by adding a new exit status,
MOUNT_BUSY to the mount.zfs program which is used when the underlying
mount(2) call returns EBUSY.  The zfs code detects this condition and
treats it as if the mount had succeeded.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #1819
Updating init scripts to have more robust grepping

The previous pattern could accidentally match on things like
'real_root=ZFS=node02-zp00/ROOT/rootfs' due to the 'ZFS=no'
substring.

Signed-off-by: Matthew Thode <mthode@mthode.org>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #1837
Explain 'zfs list -t snap -o name -s name' speedup

Commit 0cee240 from FreeBSD dramatically speeds up 'zfs list'
performance assuming you're only interested in the dataset
names.  This optimization should be mentioned in the man page
to allow end users to take advantage of it.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #1847
pep8 code readability changes

Update the code to follow the pep8 style guide.

References:
  http://www.python.org/dev/peps/pep-0008/

Signed-off-by: Matthew Thode <prometheanfire@gentoo.org>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #1838
Python 3 fixes

Future proofing for compatibility with newer versions of Python.

Signed-off-by: Matthew Thode <prometheanfire@gentoo.org>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #1838