7 files changed, 212 insertions, 81 deletions

diff --git a/stand/efi/loader/main.c b/stand/efi/loader/main.c
index 8ba03141c95b..e81a01de8b1e 100644
--- a/stand/efi/loader/main.c
+++ b/stand/efi/loader/main.c
@@ -269,7 +269,7 @@ probe_zfs_currdev(uint64_t guid)
 	currdev.root_guid = 0;
 	set_currdev_devdesc((struct devdesc *)&currdev);
 	devname = efi_fmtdev(&currdev);
-	init_zfs_bootenv(devname);
+	init_zfs_boot_options(devname);
 
 	rv = sanity_check_currdev();
 	if (rv) {
diff --git a/stand/i386/loader/main.c b/stand/i386/loader/main.c
index 377075f100ee..d7c23ba807ad 100644
--- a/stand/i386/loader/main.c
+++ b/stand/i386/loader/main.c
@@ -363,7 +363,7 @@ extract_currdev(void)
 
 #ifdef LOADER_ZFS_SUPPORT
 	if (new_currdev.dd.d_dev->dv_type == DEVT_ZFS)
-		init_zfs_bootenv(zfs_fmtdev(&new_currdev));
+		init_zfs_boot_options(zfs_fmtdev(&new_currdev));
 #endif
 
 	env_setenv("currdev", EV_VOLATILE, i386_fmtdev(&new_currdev),
diff --git a/stand/libsa/zfs/libzfs.h b/stand/libsa/zfs/libzfs.h
index a5df0c1b8255..e9eb717f0cb0 100644
--- a/stand/libsa/zfs/libzfs.h
+++ b/stand/libsa/zfs/libzfs.h
@@ -123,7 +123,7 @@ int	zfs_nextboot(void *vdev, char *buf, size_t size);
 int	zfs_probe_dev(const char *devname, uint64_t *pool_guid);
 int	zfs_list(const char *name);
 uint64_t ldi_get_size(void *);
-void	init_zfs_bootenv(const char *currdev);
+void	init_zfs_boot_options(const char *currdev);
 int	zfs_bootenv(const char *name);
 int	zfs_belist_add(const char *name, uint64_t __unused);
 int	zfs_set_env(void);
diff --git a/stand/libsa/zfs/zfs.c b/stand/libsa/zfs/zfs.c
index fd7b6cbfdeba..6bceb1ee5270 100644
--- a/stand/libsa/zfs/zfs.c
+++ b/stand/libsa/zfs/zfs.c
@@ -60,7 +60,10 @@ static off_t	zfs_seek(struct open_file *f, off_t offset, int where);
 static int	zfs_stat(struct open_file *f, struct stat *sb);
 static int	zfs_readdir(struct open_file *f, struct dirent *d);
 
-static void	zfs_bootenv_initial(const char *);
+static void	zfs_bootenv_initial(const char *envname, spa_t *spa,
+		    const char *name, const char *dsname, int checkpoint);
+static void	zfs_checkpoints_initial(spa_t *spa, const char *name,
+		    const char *dsname);
 
 struct devsw zfs_dev;
 
@@ -1077,15 +1080,15 @@ zfs_fmtdev(void *vdev)
 	return (buf);
 }
 
-int
-zfs_list(const char *name)
+static int
+split_devname(const char *name, char *poolname, size_t size,
+    const char **dsnamep)
 {
-	static char	poolname[ZFS_MAXNAMELEN];
-	uint64_t	objid;
-	spa_t		*spa;
-	const char	*dsname;
-	int		len;
-	int		rv;
+	const char *dsname;
+	size_t len;
+
+	ASSERT(name != NULL);
+	ASSERT(poolname != NULL);
 
 	len = strlen(name);
 	dsname = strchr(name, '/');
@@ -1094,8 +1097,29 @@ zfs_list(const char *name)
 		dsname++;
 	} else
 		dsname = "";
-	memcpy(poolname, name, len);
-	poolname[len] = '\0';
+
+	if (len + 1 > size)
+		return (EINVAL);
+
+	strlcpy(poolname, name, len + 1);
+
+	if (dsnamep != NULL)
+		*dsnamep = dsname;
+
+	return (0);
+}
+
+int
+zfs_list(const char *name)
+{
+	static char	poolname[ZFS_MAXNAMELEN];
+	uint64_t	objid;
+	spa_t		*spa;
+	const char	*dsname;
+	int		rv;
+
+	if (split_devname(name, poolname, sizeof(poolname), &dsname) != 0)
+		return (EINVAL);
 
 	spa = spa_find_by_name(poolname);
 	if (!spa)
@@ -1108,10 +1132,13 @@ zfs_list(const char *name)
 }
 
 void
-init_zfs_bootenv(const char *currdev_in)
+init_zfs_boot_options(const char *currdev_in)
 {
+	char poolname[ZFS_MAXNAMELEN];
 	char *beroot, *currdev;
+	spa_t *spa;
 	int currdev_len;
+	const char *dsname;
 
 	currdev = NULL;
 	currdev_len = strlen(currdev_in);
@@ -1124,6 +1151,7 @@ init_zfs_bootenv(const char *currdev_in)
 		return;
 	/* Remove the trailing : */
 	currdev[currdev_len - 1] = '\0';
+
 	setenv("zfs_be_active", currdev, 1);
 	setenv("zfs_be_currpage", "1", 1);
 	/* Remove the last element (current bootenv) */
@@ -1132,49 +1160,71 @@ init_zfs_bootenv(const char *currdev_in)
 		beroot[0] = '\0';
 	beroot = strchr(currdev, ':') + 1;
 	setenv("zfs_be_root", beroot, 1);
-	zfs_bootenv_initial(beroot);
+
+	if (split_devname(beroot, poolname, sizeof(poolname), &dsname) != 0)
+		return;
+
+	spa = spa_find_by_name(poolname);
+	if (spa == NULL)
+		return;
+
+	zfs_bootenv_initial("bootenvs", spa, beroot, dsname, 0);
+	zfs_checkpoints_initial(spa, beroot, dsname);
+
 	free(currdev);
 }
 
 static void
-zfs_bootenv_initial(const char *name)
+zfs_checkpoints_initial(spa_t *spa, const char *name, const char *dsname)
 {
-	char		poolname[ZFS_MAXNAMELEN], *dsname;
-	char envname[32], envval[256];
+	char envname[32];
+
+	if (spa->spa_uberblock_checkpoint.ub_checkpoint_txg != 0) {
+		snprintf(envname, sizeof(envname), "zpool_checkpoint");
+		setenv(envname, name, 1);
+
+		spa->spa_uberblock = &spa->spa_uberblock_checkpoint;
+		spa->spa_mos = &spa->spa_mos_checkpoint;
+
+		zfs_bootenv_initial("bootenvs_check", spa, name, dsname, 1);
+
+		spa->spa_uberblock = &spa->spa_uberblock_master;
+		spa->spa_mos = &spa->spa_mos_master;
+	}
+}
+
+static void
+zfs_bootenv_initial(const char *envprefix, spa_t *spa, const char *rootname,
+   const char *dsname, int checkpoint)
+{
+	char		envname[32], envval[256];
 	uint64_t	objid;
-	spa_t		*spa;
-	int		bootenvs_idx, len, rv;
+	int		bootenvs_idx, rv;
 
 	SLIST_INIT(&zfs_be_head);
 	zfs_env_count = 0;
-	len = strlen(name);
-	dsname = strchr(name, '/');
-	if (dsname != NULL) {
-		len = dsname - name;
-		dsname++;
-	} else
-		dsname = "";
-	strlcpy(poolname, name, len + 1);
-	spa = spa_find_by_name(poolname);
-	if (spa == NULL)
-		return;
+
 	rv = zfs_lookup_dataset(spa, dsname, &objid);
 	if (rv != 0)
 		return;
+
 	rv = zfs_callback_dataset(spa, objid, zfs_belist_add);
 	bootenvs_idx = 0;
 	/* Populate the initial environment variables */
 	SLIST_FOREACH_SAFE(zfs_be, &zfs_be_head, entries, zfs_be_tmp) {
 		/* Enumerate all bootenvs for general usage */
-		snprintf(envname, sizeof(envname), "bootenvs[%d]", bootenvs_idx);
-		snprintf(envval, sizeof(envval), "zfs:%s/%s", name, zfs_be->name);
+		snprintf(envname, sizeof(envname), "%s[%d]",
+		    envprefix, bootenvs_idx);
+		snprintf(envval, sizeof(envval), "zfs:%s%s/%s",
+		    checkpoint ? "!" : "", rootname, zfs_be->name);
 		rv = setenv(envname, envval, 1);
 		if (rv != 0)
 			break;
 		bootenvs_idx++;
 	}
+	snprintf(envname, sizeof(envname), "%s_count", envprefix);
 	snprintf(envval, sizeof(envval), "%d", bootenvs_idx);
-	setenv("bootenvs_count", envval, 1);
+	setenv(envname, envval, 1);
 
 	/* Clean up the SLIST of ZFS BEs */
 	while (!SLIST_EMPTY(&zfs_be_head)) {
@@ -1183,19 +1233,17 @@ zfs_bootenv_initial(const char *name)
 		free(zfs_be->name);
 		free(zfs_be);
 	}
-
-	return;
-
 }
 
 int
 zfs_bootenv(const char *name)
 {
-	static char	poolname[ZFS_MAXNAMELEN], *dsname, *root;
+	char		poolname[ZFS_MAXNAMELEN], *root;
+	const char	*dsname;
 	char		becount[4];
 	uint64_t	objid;
 	spa_t		*spa;
-	int		len, rv, pages, perpage, currpage;
+	int		rv, pages, perpage, currpage;
 
 	if (name == NULL)
 		return (EINVAL);
@@ -1209,15 +1257,9 @@ zfs_bootenv(const char *name)
 
 	SLIST_INIT(&zfs_be_head);
 	zfs_env_count = 0;
-	len = strlen(name);
-	dsname = strchr(name, '/');
-	if (dsname != NULL) {
-		len = dsname - name;
-		dsname++;
-	} else
-		dsname = "";
-	memcpy(poolname, name, len);
-	poolname[len] = '\0';
+
+	if (split_devname(name, poolname, sizeof(poolname), &dsname) != 0)
+		return (EINVAL);
 
 	spa = spa_find_by_name(poolname);
 	if (!spa)
@@ -1307,7 +1349,7 @@ zfs_set_env(void)
 			ctr++;
 			continue;
 		}
-		
+
 		snprintf(envname, sizeof(envname), "bootenvmenu_caption[%d]", zfs_env_index);
 		snprintf(envval, sizeof(envval), "%s", zfs_be->name);
 		rv = setenv(envname, envval, 1);
@@ -1340,7 +1382,7 @@ zfs_set_env(void)
 		}
 
 	}
-	
+
 	for (; zfs_env_index <= ZFS_BE_LAST; zfs_env_index++) {
 		snprintf(envname, sizeof(envname), "bootenvmenu_caption[%d]", zfs_env_index);
 		(void)unsetenv(envname);
diff --git a/stand/libsa/zfs/zfsimpl.c b/stand/libsa/zfs/zfsimpl.c
index 0e97e06245b3..152c0459c2be 100644
--- a/stand/libsa/zfs/zfsimpl.c
+++ b/stand/libsa/zfs/zfsimpl.c
@@ -699,7 +699,7 @@ vdev_indirect_read(vdev_t *vdev, const blkptr_t *bp, void *buf,
 
 		vic = &vdev->vdev_indirect_config;
 		vdev->v_mapping = vdev_indirect_mapping_open(spa,
-		    &spa->spa_mos, vic->vic_mapping_object);
+		    spa->spa_mos, vic->vic_mapping_object);
 	}
 
 	vdev_indirect_remap(vdev, offset, bytes, &zio);
@@ -1347,6 +1347,8 @@ spa_create(uint64_t guid, const char *name)
 		free(spa);
 		return (NULL);
 	}
+	spa->spa_uberblock = &spa->spa_uberblock_master;
+	spa->spa_mos = &spa->spa_mos_master;
 	spa->spa_guid = guid;
 	spa->spa_root_vdev = vdev_create(guid, NULL);
 	if (spa->spa_root_vdev == NULL) {
@@ -1883,7 +1885,7 @@ vdev_probe(vdev_phys_read_t *_read, void *read_priv, spa_t **spap)
 	 * the best uberblock and then we can actually access
 	 * the contents of the pool.
 	 */
-	vdev_uberblock_load(vdev, &spa->spa_uberblock);
+	vdev_uberblock_load(vdev, spa->spa_uberblock);
 
 	if (spap != NULL)
 		*spap = spa;
@@ -2409,8 +2411,9 @@ fzap_lookup(const spa_t *spa, const dnode_phys_t *dnode, zap_phys_t *zh,
 	if (zh->zap_magic != ZAP_MAGIC)
 		return (EIO);
 
-	if ((rc = fzap_check_size(integer_size, num_integers)) != 0)
+	if ((rc = fzap_check_size(integer_size, num_integers)) != 0) {
 		return (rc);
+	}
 
 	z.zap_block_shift = ilog2(bsize);
 	z.zap_phys = zh;
@@ -2766,7 +2769,7 @@ zfs_rlookup(const spa_t *spa, uint64_t objnum, char *result)
 	p = &name[sizeof(name) - 1];
 	*p = '\0';
 
-	if (objset_get_dnode(spa, &spa->spa_mos, objnum, &dataset)) {
+	if (objset_get_dnode(spa, spa->spa_mos, objnum, &dataset)) {
 		printf("ZFS: can't find dataset %ju\n", (uintmax_t)objnum);
 		return (EIO);
 	}
@@ -2774,7 +2777,7 @@ zfs_rlookup(const spa_t *spa, uint64_t objnum, char *result)
 	dir_obj = ds->ds_dir_obj;
 
 	for (;;) {
-		if (objset_get_dnode(spa, &spa->spa_mos, dir_obj, &dir) != 0)
+		if (objset_get_dnode(spa, spa->spa_mos, dir_obj, &dir) != 0)
 			return (EIO);
 		dd = (dsl_dir_phys_t *)&dir.dn_bonus;
 
@@ -2783,12 +2786,12 @@ zfs_rlookup(const spa_t *spa, uint64_t objnum, char *result)
 		if (parent_obj == 0)
 			break;
 
-		if (objset_get_dnode(spa, &spa->spa_mos, parent_obj,
+		if (objset_get_dnode(spa, spa->spa_mos, parent_obj,
 		    &parent) != 0)
 			return (EIO);
 		dd = (dsl_dir_phys_t *)&parent.dn_bonus;
 		child_dir_zapobj = dd->dd_child_dir_zapobj;
-		if (objset_get_dnode(spa, &spa->spa_mos, child_dir_zapobj,
+		if (objset_get_dnode(spa, spa->spa_mos, child_dir_zapobj,
 		    &child_dir_zap) != 0)
 			return (EIO);
 		if (zap_rlookup(spa, &child_dir_zap, component, dir_obj) != 0)
@@ -2820,7 +2823,7 @@ zfs_lookup_dataset(const spa_t *spa, const char *name, uint64_t *objnum)
 	dsl_dir_phys_t *dd;
 	const char *p, *q;
 
-	if (objset_get_dnode(spa, &spa->spa_mos,
+	if (objset_get_dnode(spa, spa->spa_mos,
 	    DMU_POOL_DIRECTORY_OBJECT, &dir))
 		return (EIO);
 	if (zap_lookup(spa, &dir, DMU_POOL_ROOT_DATASET, sizeof (dir_obj),
@@ -2829,7 +2832,7 @@ zfs_lookup_dataset(const spa_t *spa, const char *name, uint64_t *objnum)
 
 	p = name;
 	for (;;) {
-		if (objset_get_dnode(spa, &spa->spa_mos, dir_obj, &dir))
+		if (objset_get_dnode(spa, spa->spa_mos, dir_obj, &dir))
 			return (EIO);
 		dd = (dsl_dir_phys_t *)&dir.dn_bonus;
 
@@ -2850,7 +2853,7 @@ zfs_lookup_dataset(const spa_t *spa, const char *name, uint64_t *objnum)
 		}
 
 		child_dir_zapobj = dd->dd_child_dir_zapobj;
-		if (objset_get_dnode(spa, &spa->spa_mos, child_dir_zapobj,
+		if (objset_get_dnode(spa, spa->spa_mos, child_dir_zapobj,
 		    &child_dir_zap) != 0)
 			return (EIO);
 
@@ -2873,21 +2876,21 @@ zfs_list_dataset(const spa_t *spa, uint64_t objnum/*, int pos, char *entry*/)
 	dsl_dataset_phys_t *ds;
 	dsl_dir_phys_t *dd;
 
-	if (objset_get_dnode(spa, &spa->spa_mos, objnum, &dataset)) {
+	if (objset_get_dnode(spa, spa->spa_mos, objnum, &dataset)) {
 		printf("ZFS: can't find dataset %ju\n", (uintmax_t)objnum);
 		return (EIO);
 	}
 	ds = (dsl_dataset_phys_t *)&dataset.dn_bonus;
 	dir_obj = ds->ds_dir_obj;
 
-	if (objset_get_dnode(spa, &spa->spa_mos, dir_obj, &dir)) {
+	if (objset_get_dnode(spa, spa->spa_mos, dir_obj, &dir)) {
 		printf("ZFS: can't find dirobj %ju\n", (uintmax_t)dir_obj);
 		return (EIO);
 	}
 	dd = (dsl_dir_phys_t *)&dir.dn_bonus;
 
 	child_dir_zapobj = dd->dd_child_dir_zapobj;
-	if (objset_get_dnode(spa, &spa->spa_mos, child_dir_zapobj,
+	if (objset_get_dnode(spa, spa->spa_mos, child_dir_zapobj,
 	    &child_dir_zap) != 0) {
 		printf("ZFS: can't find child zap %ju\n", (uintmax_t)dir_obj);
 		return (EIO);
@@ -2908,7 +2911,7 @@ zfs_callback_dataset(const spa_t *spa, uint64_t objnum,
 	size_t size;
 	int err;
 
-	err = objset_get_dnode(spa, &spa->spa_mos, objnum, &dataset);
+	err = objset_get_dnode(spa, spa->spa_mos, objnum, &dataset);
 	if (err != 0) {
 		printf("ZFS: can't find dataset %ju\n", (uintmax_t)objnum);
 		return (err);
@@ -2916,7 +2919,7 @@ zfs_callback_dataset(const spa_t *spa, uint64_t objnum,
 	ds = (dsl_dataset_phys_t *)&dataset.dn_bonus;
 	dir_obj = ds->ds_dir_obj;
 
-	err = objset_get_dnode(spa, &spa->spa_mos, dir_obj, &dir);
+	err = objset_get_dnode(spa, spa->spa_mos, dir_obj, &dir);
 	if (err != 0) {
 		printf("ZFS: can't find dirobj %ju\n", (uintmax_t)dir_obj);
 		return (err);
@@ -2924,7 +2927,7 @@ zfs_callback_dataset(const spa_t *spa, uint64_t objnum,
 	dd = (dsl_dir_phys_t *)&dir.dn_bonus;
 
 	child_dir_zapobj = dd->dd_child_dir_zapobj;
-	err = objset_get_dnode(spa, &spa->spa_mos, child_dir_zapobj,
+	err = objset_get_dnode(spa, spa->spa_mos, child_dir_zapobj,
 	    &child_dir_zap);
 	if (err != 0) {
 		printf("ZFS: can't find child zap %ju\n", (uintmax_t)dir_obj);
@@ -2962,7 +2965,7 @@ zfs_mount_dataset(const spa_t *spa, uint64_t objnum, objset_phys_t *objset)
 	dnode_phys_t dataset;
 	dsl_dataset_phys_t *ds;
 
-	if (objset_get_dnode(spa, &spa->spa_mos, objnum, &dataset)) {
+	if (objset_get_dnode(spa, spa->spa_mos, objnum, &dataset)) {
 		printf("ZFS: can't find dataset %ju\n", (uintmax_t)objnum);
 		return (EIO);
 	}
@@ -2992,7 +2995,7 @@ zfs_get_root(const spa_t *spa, uint64_t *objid)
 	/*
 	 * Start with the MOS directory object.
 	 */
-	if (objset_get_dnode(spa, &spa->spa_mos,
+	if (objset_get_dnode(spa, spa->spa_mos,
 	    DMU_POOL_DIRECTORY_OBJECT, &dir)) {
 		printf("ZFS: can't read MOS object directory\n");
 		return (EIO);
@@ -3003,7 +3006,7 @@ zfs_get_root(const spa_t *spa, uint64_t *objid)
 	 */
 	if (zap_lookup(spa, &dir, DMU_POOL_PROPS,
 	    sizeof(props), 1, &props) == 0 &&
-	    objset_get_dnode(spa, &spa->spa_mos, props, &propdir) == 0 &&
+	    objset_get_dnode(spa, spa->spa_mos, props, &propdir) == 0 &&
 	    zap_lookup(spa, &propdir, "bootfs",
 	    sizeof(bootfs), 1, &bootfs) == 0 && bootfs != 0) {
 		*objid = bootfs;
@@ -3014,7 +3017,7 @@ zfs_get_root(const spa_t *spa, uint64_t *objid)
 	 */
 	if (zap_lookup(spa, &dir, DMU_POOL_ROOT_DATASET,
 	    sizeof(root), 1, &root) ||
-	    objset_get_dnode(spa, &spa->spa_mos, root, &dir)) {
+	    objset_get_dnode(spa, spa->spa_mos, root, &dir)) {
 		printf("ZFS: can't find root dsl_dir\n");
 		return (EIO);
 	}
@@ -3085,7 +3088,7 @@ check_mos_features(const spa_t *spa)
 	size_t size;
 	int rc;
 
-	if ((rc = objset_get_dnode(spa, &spa->spa_mos, DMU_OT_OBJECT_DIRECTORY,
+	if ((rc = objset_get_dnode(spa, spa->spa_mos, DMU_OT_OBJECT_DIRECTORY,
 	    &dir)) != 0)
 		return (rc);
 	if ((rc = zap_lookup(spa, &dir, DMU_POOL_FEATURES_FOR_READ,
@@ -3097,7 +3100,7 @@ check_mos_features(const spa_t *spa)
 		return (0);
 	}
 
-	if ((rc = objset_get_dnode(spa, &spa->spa_mos, objnum, &dir)) != 0)
+	if ((rc = objset_get_dnode(spa, spa->spa_mos, objnum, &dir)) != 0)
 		return (rc);
 
 	if (dir.dn_type != DMU_OTN_ZAP_METADATA)
@@ -3131,7 +3134,7 @@ load_nvlist(spa_t *spa, uint64_t obj, nvlist_t **value)
 	unsigned char *nv;
 
 	*value = NULL;
-	if ((rc = objset_get_dnode(spa, &spa->spa_mos, obj, &dir)) != 0)
+	if ((rc = objset_get_dnode(spa, spa->spa_mos, obj, &dir)) != 0)
 		return (rc);
 	if (dir.dn_type != DMU_OT_PACKED_NVLIST &&
 	    dir.dn_bonustype != DMU_OT_PACKED_NVLIST_SIZE) {
@@ -3160,22 +3163,23 @@ load_nvlist(spa_t *spa, uint64_t obj, nvlist_t **value)
 static int
 zfs_spa_init(spa_t *spa)
 {
+	struct uberblock checkpoint;
 	dnode_phys_t dir;
 	uint64_t config_object;
 	nvlist_t *nvlist;
 	int rc;
 
-	if (zio_read(spa, &spa->spa_uberblock.ub_rootbp, &spa->spa_mos)) {
+	if (zio_read(spa, &spa->spa_uberblock->ub_rootbp, spa->spa_mos)) {
 		printf("ZFS: can't read MOS of pool %s\n", spa->spa_name);
 		return (EIO);
 	}
-	if (spa->spa_mos.os_type != DMU_OST_META) {
+	if (spa->spa_mos->os_type != DMU_OST_META) {
 		printf("ZFS: corrupted MOS of pool %s\n", spa->spa_name);
 		return (EIO);
 	}
 
-	if (objset_get_dnode(spa, &spa->spa_mos, DMU_POOL_DIRECTORY_OBJECT,
-	    &dir)) {
+	if (objset_get_dnode(spa, &spa->spa_mos_master,
+	    DMU_POOL_DIRECTORY_OBJECT, &dir)) {
 		printf("ZFS: failed to read pool %s directory object\n",
 		    spa->spa_name);
 		return (EIO);
@@ -3200,6 +3204,20 @@ zfs_spa_init(spa_t *spa)
 	rc = load_nvlist(spa, config_object, &nvlist);
 	if (rc != 0)
 		return (rc);
+
+	rc = zap_lookup(spa, &dir, DMU_POOL_ZPOOL_CHECKPOINT,
+	    sizeof(uint64_t), sizeof(checkpoint) / sizeof(uint64_t),
+	    &checkpoint);
+	if (rc == 0 && checkpoint.ub_checkpoint_txg != 0) {
+		memcpy(&spa->spa_uberblock_checkpoint, &checkpoint,
+		    sizeof(checkpoint));
+		if (zio_read(spa, &spa->spa_uberblock_checkpoint.ub_rootbp,
+		    &spa->spa_mos_checkpoint)) {
+			printf("ZFS: can not read checkpoint data.\n");
+			return (EIO);
+		}
+	}
+
 	/*
 	 * Update vdevs from MOS config. Note, we do skip encoding bytes
 	 * here. See also vdev_label_read_config().
diff --git a/stand/lua/core.lua b/stand/lua/core.lua
index 448215d97d03..c56443e98733 100644
--- a/stand/lua/core.lua
+++ b/stand/lua/core.lua
@@ -38,6 +38,8 @@ local default_safe_mode = false
 local default_single_user = false
 local default_verbose = false
 
+local bootenv_list = "bootenvs"
+
 local function composeLoaderCmd(cmd_name, argstr)
 	if argstr ~= nil then
 		cmd_name = cmd_name .. " " .. argstr
@@ -270,7 +272,7 @@ function core.bootenvDefault()
 end
 
 function core.bootenvList()
-	local bootenv_count = tonumber(loader.getenv("bootenvs_count"))
+	local bootenv_count = tonumber(loader.getenv(bootenv_list .. "_count"))
 	local bootenvs = {}
 	local curenv
 	local envcount = 0
@@ -281,7 +283,12 @@ function core.bootenvList()
 	end
 
 	-- Currently selected bootenv is always first/default
-	curenv = core.bootenvDefault()
+	-- On the rewinded list the bootenv may not exists
+	if core.isRewinded() then
+		curenv = core.bootenvDefaultRewinded()
+	else
+		curenv = core.bootenvDefault()
+	end
 	if curenv ~= nil then
 		envcount = envcount + 1
 		bootenvs[envcount] = curenv
@@ -289,7 +296,7 @@ function core.bootenvList()
 	end
 
 	for curenv_idx = 0, bootenv_count - 1 do
-		curenv = loader.getenv("bootenvs[" .. curenv_idx .. "]")
+		curenv = loader.getenv(bootenv_list .. "[" .. curenv_idx .. "]")
 		if curenv ~= nil and unique[curenv] == nil then
 			envcount = envcount + 1
 			bootenvs[envcount] = curenv
@@ -299,6 +306,40 @@ function core.bootenvList()
 	return bootenvs
 end
 
+function core.isCheckpointed()
+	return loader.getenv("zpool_checkpoint") ~= nil
+end
+
+function core.bootenvDefaultRewinded()
+	local defname =  "zfs:!" .. string.sub(core.bootenvDefault(), 5)
+	local bootenv_count = tonumber("bootenvs_check_count")
+
+	if bootenv_count == nil or bootenv_count <= 0 then
+		return defname
+	end
+
+	for curenv_idx = 0, bootenv_count - 1 do
+		curenv = loader.getenv("bootenvs_check[" .. curenv_idx .. "]")
+		if curenv == defname then
+			return defname
+		end
+	end
+
+	return loader.getenv("bootenvs_check[0]")
+end
+
+function core.isRewinded()
+	return bootenv_list == "bootenvs_check"
+end
+
+function core.changeRewindCheckpoint()
+	if core.isRewinded() then
+		bootenv_list = "bootenvs"
+	else
+		bootenv_list = "bootenvs_check"
+	end
+end
+
 function core.setDefaults()
 	core.setACPI(core.getACPIPresent(true))
 	core.setSafeMode(default_safe_mode)
diff --git a/stand/lua/menu.lua b/stand/lua/menu.lua
index 32f414f7fbfa..103ec9c00050 100644
--- a/stand/lua/menu.lua
+++ b/stand/lua/menu.lua
@@ -132,6 +132,9 @@ menu.boot_environments = {
 		},
 		{
 			entry_type = core.MENU_ENTRY,
+			visible = function()
+				return core.isRewinded() == false
+			end,
 			name = function()
 				return color.highlight("b") .. "ootfs: " ..
 				    core.bootenvDefault()
@@ -250,6 +253,7 @@ menu.welcome = {
 			},
 			menu_entries.kernel_options,
 			menu_entries.boot_options,
+			menu_entries.zpool_checkpoints,
 			menu_entries.boot_envs,
 			menu_entries.chainload,
 		}
@@ -334,6 +338,32 @@ menu.welcome = {
 			submenu = menu.boot_options,
 			alias = {"o", "O"},
 		},
+		zpool_checkpoints = {
+			entry_type = core.MENU_ENTRY,
+			name = function()
+				rewind = "No"
+				if core.isRewinded() then
+					rewind = "Yes"
+				end
+				return "Rewind ZFS " .. color.highlight("C") ..
+					"heckpoint: " .. rewind
+			end,
+			func = function()
+				core.changeRewindCheckpoint()
+				if core.isRewinded() then
+					bootenvSet(
+					    core.bootenvDefaultRewinded())
+				else
+					bootenvSet(core.bootenvDefault())
+				end
+				config.setCarouselIndex("be_active", 1)
+			end,
+			visible = function()
+				return core.isZFSBoot() and
+				    core.isCheckpointed()
+			end,
+			alias = {"c", "C"},
+		},
 		boot_envs = {
 			entry_type = core.MENU_SUBMENU,
 			visible = function()