Merge libzfs_core branch:

  includes MFV 238590, 238592, 247580

MFV 238590, 238592:
  In the first zfs ioctl restructuring phase, the libzfs_core library was
  introduced. It is a new thin library that wraps around kernel ioctl's.
  The idea is to provide a forward-compatible way of dealing with new
  features. Arguments are passed in nvlists and not random zfs_cmd fields,
  new-style ioctls are logged to pool history using a new method of
  history logging.

  http://blog.delphix.com/matt/2012/01/17/the-future-of-libzfs/

MFV 247580 [1]:
  To address issues of several deadlocks and race conditions the locking
  code around dsl_dataset was rewritten and the interface to synctasks
  was changed.

User-Visible Changes:
  "zfs snapshot" can create more arbitrary snapshots at once (atomically)
  "zfs destroy" destroys multiple snapshots at once
  "zfs recv" has improved performance

Backward Compatibility:
  I have extended the compatibility layer to support full backward
  compatibility by remapping or rewriting the responsible ioctl arguments.
  Old utilities are fully supported by the new kernel module.

Forward Compatibility:
  New utilities work with old kernels with the following restrictions:
    - creating, destroying, holding and releasing of multiple snapshots
      at once is not supported, this includes recursive (-r) commands

Illumos ZFS issues:
  2882 implement libzfs_core
  2900 "zfs snapshot" should be able to create multiple,
       arbitrary snapshots at once
  3464 zfs synctask code needs restructuring

References:
  https://www.illumos.org/issues/2882
  https://www.illumos.org/issues/2900
  https://www.illumos.org/issues/3464 [1]

MFC after:	1 month
Sponsored by:	Hybrid Logic Inc. [1]

1 files changed, 13 insertions, 7 deletions

diff --git a/cddl/contrib/opensolaris/cmd/zfs/zfs.8 b/cddl/contrib/opensolaris/cmd/zfs/zfs.8
index 9c882da7f17b..a7a51c971012 100644
--- a/cddl/contrib/opensolaris/cmd/zfs/zfs.8
+++ b/cddl/contrib/opensolaris/cmd/zfs/zfs.8
@@ -28,7 +28,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd March 1, 2013
+.Dd March 21, 2013
 .Dt ZFS 8
 .Os
 .Sh NAME
@@ -65,6 +65,7 @@
 .Op Fl r
 .Oo Fl o Ar property Ns = Ns Ar value Oc Ns ...
 .Ar filesystem@snapname Ns | Ns Ar volume@snapname
+.Ar filesystem@snapname Ns | Ns Ar volume@snapname Ns ...
 .Nm
 .Cm rollback
 .Op Fl rRf
@@ -1617,7 +1618,11 @@ multiple snapshots.
 Destroy (or mark for deferred deletion) all snapshots with this name in
 descendent file systems.
 .It Fl R
-Recursively destroy all dependents.
+Recursively destroy all clones of these snapshots, including the clones,
+snapshots, and children.
+If this flag is specified, the
+.Op fl d
+flag will have no effect.
 .It Fl n
 Do a dry-run ("No-op") deletion. No data will be deleted. This is useful in
 conjunction with the
@@ -1645,17 +1650,18 @@ behavior for mounted file systems in use.
 .Op Fl r
 .Oo Fl o Ar property Ns = Ns Ar value Oc Ns ...
 .Ar filesystem@snapname Ns | Ns volume@snapname
+.Ar filesystem@snapname Ns | Ns volume@snapname Ns ...
 .Xc
 .Pp
-Creates a snapshot with the given name. All previous modifications by
-successful system calls to the file system are part of the snapshot. See the
+Creates snapshots with the given names. All previous modifications by
+successful system calls to the file system are part of the snapshots.
+Snapshots are taken atomically, so that all snapshots correspond to the same
+moment in time. See the
 .Qq Sx Snapshots
 section for details.
 .Bl -tag -width indent
 .It Fl r
-Recursively create snapshots of all descendent datasets. Snapshots are taken
-atomically, so that all recursive snapshots correspond to the same moment in
-time.
+Recursively create snapshots of all descendent datasets
 .It Fl o Ar property Ns = Ns Ar value
 Sets the specified property; see
 .Qq Nm Cm create