bectl(8): create non-recursive boot environments

bectl advertises that it has the ability to create recursive and
non-recursive boot environments. This patch implements that functionality
using the be_create_depth API provided by libbe. With this patch, bectl now
works as bectl(8) describes in regards to creating recursive/non-recursive
boot environments.

Submitted by:	Rob Fairbanks <rob.fx907 gmail com> (with minor changes)
MFC after:	1 week
Differential Revision:	https://reviews.freebsd.org/D20240

sbin/bectl/bectl.c

@@ -184,7 +184,8 @@ bectl_cmd_activate(int argc, char *argv[])
 static int
 bectl_cmd_create(int argc, char *argv[])
 {
-	char *atpos, *bootenv, *snapname, *source;
+	char snapshot[BE_MAXPATHLEN];
+	char *atpos, *bootenv, *snapname;
 	int err, opt;
 	bool recursive;
 
@@ -214,6 +215,8 @@ bectl_cmd_create(int argc, char *argv[])
 	}
 
 	bootenv = *argv;
+
+	err = BE_ERR_SUCCESS;
 	if ((atpos = strchr(bootenv, '@')) != NULL) {
 		/*
 		 * This is the "create a snapshot variant". No new boot
@@ -221,24 +224,22 @@ bectl_cmd_create(int argc, char *argv[])
 		 */
 		*atpos++ = '\0';
 		err = be_snapshot(be, bootenv, atpos, recursive, NULL);
-	} else if (snapname != NULL) {
-		if (strchr(snapname, '@') != NULL)
-			err = be_create_from_existing_snap(be, bootenv,
-			    snapname);
-		else
-			err = be_create_from_existing(be, bootenv, snapname);
 	} else {
-		if ((snapname = strchr(bootenv, '@')) != NULL) {
+		if (snapname == NULL)
-			*(snapname++) = '\0';
+			/* Create from currently booted BE */
-			if ((err = be_snapshot(be, be_active_path(be),
+			err = be_snapshot(be, be_active_path(be), NULL,
-			    snapname, true, NULL)) != BE_ERR_SUCCESS)
+			    recursive, snapshot);
-				fprintf(stderr, "failed to create snapshot\n");
+		else if (strchr(snapname, '@') != NULL)
-			asprintf(&source, "%s@%s", be_active_path(be), snapname);
+			/* Create from given snapshot */
-			err = be_create_from_existing_snap(be, bootenv,
+			strlcpy(snapshot, snapname, sizeof(snapshot));
-			    source);
+		else
-			return (err);
+			/* Create from given BE */
-		} else
+			err = be_snapshot(be, snapname, NULL, recursive,
-			err = be_create(be, bootenv);
+			    snapshot);
+
+		if (err == BE_ERR_SUCCESS)
+			err = be_create_depth(be, bootenv, snapshot,
+					      recursive == true ? -1 : 0);
 	}
 
 	switch (err) {

sbin/bectl/tests/bectl_test.sh

@@ -99,11 +99,35 @@ bectl_create_body()
 	mount=${cwd}/mnt
 
 	bectl_create_setup ${zpool} ${disk} ${mount}
+
+	# Create a child dataset that will be used to test creation
+	# of recursive and non-recursive boot environments.
+	atf_check zfs create -o mountpoint=/usr -o canmount=noauto \
+	    ${zpool}/ROOT/default/usr
+
 	# Test standard creation, creation of a snapshot, and creation from a
 	# snapshot.
 	atf_check bectl -r ${zpool}/ROOT create -e default default2
 	atf_check bectl -r ${zpool}/ROOT create default2@test_snap
 	atf_check bectl -r ${zpool}/ROOT create -e default2@test_snap default3
+
+	# Test standard creation, creation of a snapshot, and creation from a
+	# snapshot for recursive boot environments.
+	atf_check bectl -r ${zpool}/ROOT create -r -e default recursive
+	atf_check bectl -r ${zpool}/ROOT create -r recursive@test_snap
+	atf_check bectl -r ${zpool}/ROOT create -r -e recursive@test_snap recursive-snap
+
+	# Test that non-recursive boot environments have no child datasets.
+	atf_check -e not-empty -s not-exit:0 \
+		zfs list "${zpool}/ROOT/default2/usr"
+	atf_check -e not-empty -s not-exit:0 \
+		zfs list "${zpool}/ROOT/default3/usr"
+
+	# Test that recursive boot environments have child datasets.
+	atf_check -o not-empty \
+		zfs list "${zpool}/ROOT/recursive/usr"
+	atf_check -o not-empty \
+		zfs list "${zpool}/ROOT/recursive-snap/usr"
 }
 bectl_create_cleanup()
 {