Various fixes for zvol devices not being correctly maintained when operations
which effect them occur.
--- sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dsl_dataset.c.orig	2014-03-26 17:52:33.000000000 +0000
+++ sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dsl_dataset.c	2014-09-29 18:52:24.903520480 +0000
@@ -1655,11 +1655,9 @@ static int
 dsl_dataset_rename_snapshot_sync_impl(dsl_pool_t *dp,
     dsl_dataset_t *hds, void *arg)
 {
-#ifdef __FreeBSD__
-#ifdef _KERNEL
+#if defined(__FreeBSD__) && defined(_KERNEL)
 	char *oldname, *newname;
 #endif
-#endif
 	dsl_dataset_rename_snapshot_arg_t *ddrsa = arg;
 	dsl_dataset_t *ds;
 	uint64_t val;
@@ -1686,8 +1684,7 @@ dsl_dataset_rename_snapshot_sync_impl(ds
 	VERIFY0(zap_add(dp->dp_meta_objset, hds->ds_phys->ds_snapnames_zapobj,
 	    ds->ds_snapname, 8, 1, &ds->ds_object, tx));
 
-#ifdef __FreeBSD__
-#ifdef _KERNEL
+#if defined(__FreeBSD__) && defined (_KERNEL)
 	oldname = kmem_alloc(MAXPATHLEN, KM_SLEEP);
 	newname = kmem_alloc(MAXPATHLEN, KM_SLEEP);
 	snprintf(oldname, MAXPATHLEN, "%s@%s", ddrsa->ddrsa_fsname,
@@ -1699,7 +1696,6 @@ dsl_dataset_rename_snapshot_sync_impl(ds
 	kmem_free(newname, MAXPATHLEN);
 	kmem_free(oldname, MAXPATHLEN);
 #endif
-#endif
 	dsl_dataset_rele(ds, FTAG);
 
 	return (0);
@@ -2076,6 +2072,9 @@ dsl_dataset_promote_sync(void *arg, dmu_
 	dsl_dir_t *odd = NULL;
 	uint64_t oldnext_obj;
 	int64_t delta;
+#if defined(__FreeBSD__) && defined(_KERNEL)
+	char *oldname, *newname;
+#endif
 
 	VERIFY0(promote_hold(ddpa, dp, FTAG));
 	hds = ddpa->ddpa_clone;
@@ -2141,6 +2140,14 @@ dsl_dataset_promote_sync(void *arg, dmu_
 		    dd->dd_phys->dd_clones, origin_head->ds_object, tx));
 	}
 
+#if defined(__FreeBSD__) && defined(_KERNEL)
+	/* Take the spa_namespace_lock so zvol renames don't livelock */
+	mutex_enter(&spa_namespace_lock);
+
+	oldname = kmem_alloc(MAXPATHLEN, KM_SLEEP);
+	newname = kmem_alloc(MAXPATHLEN, KM_SLEEP);
+#endif
+
 	/* move snapshots to this dir */
 	for (snap = list_head(&ddpa->shared_snaps); snap;
 	    snap = list_next(&ddpa->shared_snaps, snap)) {
@@ -2173,6 +2180,12 @@ dsl_dataset_promote_sync(void *arg, dmu_
 		VERIFY0(dsl_dir_hold_obj(dp, dd->dd_object,
 		    NULL, ds, &ds->ds_dir));
 
+#if defined(__FreeBSD__) && defined(_KERNEL)
+		dsl_dataset_name(ds, newname);
+		zfsvfs_update_fromname(oldname, newname);
+		zvol_rename_minors(oldname, newname);
+#endif
+
 		/* move any clone references */
 		if (ds->ds_phys->ds_next_clones_obj &&
 		    spa_version(dp->dp_spa) >= SPA_VERSION_DIR_CLONES) {
@@ -2210,6 +2223,12 @@ dsl_dataset_promote_sync(void *arg, dmu_
 		ASSERT(!dsl_prop_hascb(ds));
 	}
 
+#if defined(__FreeBSD__) && defined(_KERNEL)
+	mutex_exit(&spa_namespace_lock);
+
+	kmem_free(newname, MAXPATHLEN);
+	kmem_free(oldname, MAXPATHLEN);
+#endif
 	/*
 	 * Change space accounting.
 	 * Note, pa->*usedsnap and dd_used_breakdown[SNAP] will either
--- sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/zvol.h.orig	2014-03-26 17:52:33.000000000 +0000
+++ sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/zvol.h	2014-09-29 18:52:24.903520480 +0000
@@ -41,8 +41,7 @@ extern int zvol_check_volblocksize(uint6
 extern int zvol_get_stats(objset_t *os, nvlist_t *nv);
 extern void zvol_create_cb(objset_t *os, void *arg, cred_t *cr, dmu_tx_t *tx);
 extern int zvol_create_minor(const char *);
-extern int zvol_remove_minor(const char *);
-extern void zvol_remove_minors(const char *);
+extern int zvol_remove_minors(const char *);
 extern int zvol_set_volsize(const char *, major_t, uint64_t);
 
 #ifdef sun
--- sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_ioctl.c.orig	2014-03-26 17:52:33.000000000 +0000
+++ sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_ioctl.c	2014-09-29 18:52:24.908521871 +0000
@@ -3517,7 +3517,7 @@ zfs_ioc_destroy_snaps(const char *poolna
 		error = zfs_unmount_snap(name);
 		if (error != 0)
 			return (error);
-		(void) zvol_remove_minor(name);
+		(void) zvol_remove_minors(name);
 	}
 
 	return (dsl_destroy_snapshots_nvl(snaps, defer, outnvl));
@@ -3547,7 +3547,7 @@ zfs_ioc_destroy(zfs_cmd_t *zc)
 	else
 		err = dsl_destroy_head(zc->zc_name);
 	if (zc->zc_objset_type == DMU_OST_ZVOL && err == 0)
-		(void) zvol_remove_minor(zc->zc_name);
+		(void) zvol_remove_minors(zc->zc_name);
 	return (err);
 }
 
@@ -3643,7 +3643,7 @@ zfs_ioc_rename(zfs_cmd_t *zc)
 	} else {
 #ifdef illumos
 		if (zc->zc_objset_type == DMU_OST_ZVOL)
-			(void) zvol_remove_minor(zc->zc_name);
+			(void) zvol_remove_minors(zc->zc_name);
 #endif
 		return (dsl_dir_rename(zc->zc_name, zc->zc_value));
 	}
--- sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zvol.c.orig	2014-09-29 18:52:05.348521778 +0000
+++ sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zvol.c	2014-09-29 18:52:24.909520935 +0000
@@ -630,24 +630,6 @@ zvol_remove_zv(zvol_state_t *zv)
 }
 
 int
-zvol_remove_minor(const char *name)
-{
-	zvol_state_t *zv;
-	int rc;
-
-	mutex_enter(&spa_namespace_lock);
-	if ((zv = zvol_minor_lookup(name)) == NULL) {
-		mutex_exit(&spa_namespace_lock);
-		return (SET_ERROR(ENXIO));
-	}
-	g_topology_lock();
-	rc = zvol_remove_zv(zv);
-	g_topology_unlock();
-	mutex_exit(&spa_namespace_lock);
-	return (rc);
-}
-
-int
 zvol_first_open(zvol_state_t *zv)
 {
 	objset_t *os;
@@ -775,15 +757,17 @@ zvol_update_volsize(objset_t *os, uint64
 	return (error);
 }
 
-void
+int
 zvol_remove_minors(const char *name)
 {
 	struct g_geom *gp, *gptmp;
 	struct g_provider *pp;
 	zvol_state_t *zv;
 	size_t namelen;
+	int rc;
 
 	namelen = strlen(name);
+	rc = ENXIO;
 
 	DROP_GIANT();
 	mutex_enter(&spa_namespace_lock);
@@ -798,14 +782,18 @@ zvol_remove_minors(const char *name)
 			continue;
 		if (strcmp(zv->zv_name, name) == 0 ||
 		    (strncmp(zv->zv_name, name, namelen) == 0 &&
-		     zv->zv_name[namelen] == '/')) {
-			(void) zvol_remove_zv(zv);
+		    strlen(zv->zv_name) > namelen && (zv->zv_name[namelen] == '/' ||
+		    zv->zv_name[namelen] == '@'))) {
+			if ((rc = zvol_remove_zv(zv)) != 0)
+				break;
 		}
 	}
 
 	g_topology_unlock();
 	mutex_exit(&spa_namespace_lock);
 	PICKUP_GIANT();
+
+	return (rc);
 }
 
 int
@@ -2393,9 +2381,10 @@ zvol_create_minors(const char *name)
 	if (dmu_objset_type(os) == DMU_OST_ZVOL) {
 		dsl_dataset_long_hold(os->os_dsl_dataset, FTAG);
 		dsl_pool_rele(dmu_objset_pool(os), FTAG);
-		if ((error = zvol_create_minor(name)) == 0)
+		error = zvol_create_minor(name);
+		if (error == 0 || error == EEXIST) {
 			error = zvol_create_snapshots(os, name);
-		else {
+		} else {
 			printf("ZFS WARNING: Unable to create ZVOL %s (error=%d).\n",
 			    name, error);
 		}
@@ -2479,12 +2468,16 @@ zvol_rename_minors(const char *oldname, 
 	size_t oldnamelen, newnamelen;
 	zvol_state_t *zv;
 	char *namebuf;
+	boolean_t locked = B_FALSE;
 
 	oldnamelen = strlen(oldname);
 	newnamelen = strlen(newname);
 
 	DROP_GIANT();
-	mutex_enter(&spa_namespace_lock);
+	if (!MUTEX_HELD(&spa_namespace_lock)) {
+		mutex_enter(&spa_namespace_lock);
+		locked = B_TRUE;
+	}
 	g_topology_lock();
 
 	LIST_FOREACH(gp, &zfs_zvol_class.geom, geom) {
@@ -2507,6 +2500,7 @@ zvol_rename_minors(const char *oldname, 
 	}
 
 	g_topology_unlock();
-	mutex_exit(&spa_namespace_lock);
+	if (locked)
+		mutex_exit(&spa_namespace_lock);
 	PICKUP_GIANT();
 }