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]

Makefile.inc1

@@ -1389,6 +1389,7 @@ _prebuild_libs=	${_kerberos5_lib_libasn1} \
 		lib/libopie lib/libpam ${_lib_libthr} \
 		lib/libradius lib/libsbuf lib/libtacplus \
 		${_cddl_lib_libumem} ${_cddl_lib_libnvpair} \
+		${_cddl_lib_libzfs_core} \
 		lib/libutil ${_lib_libypclnt} lib/libz lib/msun \
 		${_secure_lib_libcrypto} ${_secure_lib_libssh} \
 		${_secure_lib_libssl}
@@ -1417,7 +1418,9 @@ lib/libopie__L lib/libtacplus__L: lib/libmd__L
 .if ${MK_CDDL} != "no"
 _cddl_lib_libumem= cddl/lib/libumem
 _cddl_lib_libnvpair= cddl/lib/libnvpair
+_cddl_lib_libzfs_core= cddl/lib/libzfs_core
 _cddl_lib= cddl/lib
+cddl/lib/libzfs_core__L: cddl/lib/libnvpair__L
 .endif
 
 .if ${MK_CRYPT} != "no"

cddl/contrib/opensolaris/cmd/zdb/zdb.c

@@ -57,6 +57,7 @@
 #include <sys/arc.h>
 #include <sys/ddt.h>
 #include <sys/zfeature.h>
+#include <zfs_comutil.h>
 #undef ZFS_MAXNAMELEN
 #undef verify
 #include <libzfs.h>
@@ -206,6 +207,27 @@ dump_packed_nvlist(objset_t *os, uint64_t object, void *data, size_t size)
 	nvlist_free(nv);
 }
 
+/* ARGSUSED */
+static void
+dump_history_offsets(objset_t *os, uint64_t object, void *data, size_t size)
+{
+	spa_history_phys_t *shp = data;
+
+	if (shp == NULL)
+		return;
+
+	(void) printf("\t\tpool_create_len = %llu\n",
+	    (u_longlong_t)shp->sh_pool_create_len);
+	(void) printf("\t\tphys_max_off = %llu\n",
+	    (u_longlong_t)shp->sh_phys_max_off);
+	(void) printf("\t\tbof = %llu\n",
+	    (u_longlong_t)shp->sh_bof);
+	(void) printf("\t\teof = %llu\n",
+	    (u_longlong_t)shp->sh_eof);
+	(void) printf("\t\trecords_lost = %llu\n",
+	    (u_longlong_t)shp->sh_records_lost);
+}
+
 static void
 zdb_nicenum(uint64_t num, char *buf)
 {
@@ -857,21 +879,22 @@ dump_history(spa_t *spa)
 	for (int i = 0; i < num; i++) {
 		uint64_t time, txg, ievent;
 		char *cmd, *intstr;
+		boolean_t printed = B_FALSE;
 
 		if (nvlist_lookup_uint64(events[i], ZPOOL_HIST_TIME,
 		    &time) != 0)
-			continue;
+			goto next;
 		if (nvlist_lookup_string(events[i], ZPOOL_HIST_CMD,
 		    &cmd) != 0) {
 			if (nvlist_lookup_uint64(events[i],
 			    ZPOOL_HIST_INT_EVENT, &ievent) != 0)
-				continue;
+				goto next;
 			verify(nvlist_lookup_uint64(events[i],
 			    ZPOOL_HIST_TXG, &txg) == 0);
 			verify(nvlist_lookup_string(events[i],
 			    ZPOOL_HIST_INT_STR, &intstr) == 0);
-			if (ievent >= LOG_END)
-				continue;
+			if (ievent >= ZFS_NUM_LEGACY_HISTORY_EVENTS)
+				goto next;
 
 			(void) snprintf(internalstr,
 			    sizeof (internalstr),
@@ -884,6 +907,14 @@ dump_history(spa_t *spa)
 		(void) localtime_r(&tsec, &t);
 		(void) strftime(tbuf, sizeof (tbuf), "%F.%T", &t);
 		(void) printf("%s %s\n", tbuf, cmd);
+		printed = B_TRUE;
+
+next:
+		if (dump_opt['h'] > 1) {
+			if (!printed)
+				(void) printf("unrecognized record:\n");
+			dump_nvlist(events[i], 2);
+		}
 	}
 }
 
@@ -1496,7 +1527,7 @@ static object_viewer_t *object_viewer[DMU_OT_NUMTYPES + 1] = {
 	dump_zap,		/* other ZAP			*/
 	dump_zap,		/* persistent error log		*/
 	dump_uint8,		/* SPA history			*/
-	dump_uint64,		/* SPA history offsets		*/
+	dump_history_offsets,	/* SPA history offsets		*/
 	dump_zap,		/* Pool properties		*/
 	dump_zap,		/* DSL permissions		*/
 	dump_acl,		/* ZFS ACL			*/
@@ -1661,7 +1692,9 @@ dump_dir(objset_t *os)
 	int print_header = 1;
 	int i, error;
 
+	dsl_pool_config_enter(dmu_objset_pool(os), FTAG);
 	dmu_objset_fast_stat(os, &dds);
+	dsl_pool_config_exit(dmu_objset_pool(os), FTAG);
 
 	if (dds.dds_type < DMU_OST_NUMTYPES)
 		type = objset_types[dds.dds_type];
@@ -2070,7 +2103,6 @@ zdb_blkptr_cb(spa_t *spa, zilog_t *zilog, const blkptr_t *bp,
 		    NULL, NULL, ZIO_PRIORITY_ASYNC_READ, flags, zb));
 
 		free(data);
-
 		if (ioerr && !(flags & ZIO_FLAG_SPECULATIVE)) {
 			zcb->zcb_haderrors = 1;
 			zcb->zcb_errors[ioerr]++;

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