ztest: update ztest_dmu_snapshot_create_destroy()

ECHRNG is returned when the channel program encounters a runtime
error.  For example, this can happen when a snapshot doesn't exist.
We handle this error the same way as the existing EEXIST and ENOENT
error checks.

Additionally, improve the internal debug message to include the
error describing why a pool couldn't be opened.

Reviewed-by: Richard Yao <richard.yao@alumni.stonybrook.edu>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes openzfs#14351

cmd/ztest.c

@@ -4299,7 +4299,7 @@ ztest_snapshot_create(char *osname, uint64_t id)
 		ztest_record_enospc(FTAG);
 		return (B_FALSE);
 	}
-	if (error != 0 && error != EEXIST) {
+	if (error != 0 && error != EEXIST && error != ECHRNG) {
 		fatal(B_FALSE, "ztest_snapshot_create(%s@%s) = %d", osname,
 		    snapname, error);
 	}
@@ -4316,7 +4316,7 @@ ztest_snapshot_destroy(char *osname, uint64_t id)
 	    osname, id);
 
 	error = dsl_destroy_snapshot(snapname, B_FALSE);
-	if (error != 0 && error != ENOENT)
+	if (error != 0 && error != ENOENT && error != ECHRNG)
 		fatal(B_FALSE, "ztest_snapshot_destroy(%s) = %d",
 		    snapname, error);
 	return (B_TRUE);
@@ -4365,9 +4365,16 @@ ztest_dmu_objset_create_destroy(ztest_ds_t *zd, uint64_t id)
 
 	/*
 	 * Verify that the destroyed dataset is no longer in the namespace.
+	 * It may still be present if the destroy above fails with ENOSPC.
 	 */
-	VERIFY3U(ENOENT, ==, ztest_dmu_objset_own(name, DMU_OST_OTHER, B_TRUE,
-	    B_TRUE, FTAG, &os));
+	error = ztest_dmu_objset_own(name, DMU_OST_OTHER, B_TRUE, B_TRUE,
+	    FTAG, &os);
+	if (error == 0) {
+		dmu_objset_disown(os, B_TRUE, FTAG);
+		ztest_record_enospc(FTAG);
+		goto out;
+	}
+	VERIFY3U(ENOENT, ==, error);
 
 	/*
 	 * Verify that we can create a new dataset.

module/zfs/zcp.c

@@ -958,12 +958,12 @@ zcp_eval_impl(dmu_tx_t *tx, zcp_run_info_t *ri)
 }
 
 static void
-zcp_pool_error(zcp_run_info_t *ri, const char *poolname)
+zcp_pool_error(zcp_run_info_t *ri, const char *poolname, int error)
 {
 	ri->zri_result = SET_ERROR(ECHRNG);
 	lua_settop(ri->zri_state, 0);
-	(void) lua_pushfstring(ri->zri_state, "Could not open pool: %s",
-	    poolname);
+	(void) lua_pushfstring(ri->zri_state, "Could not open pool: %s "
+	    "errno: %d", poolname, error);
 	zcp_convert_return_values(ri->zri_state, ri->zri_outnvl,
 	    ZCP_RET_ERROR, &ri->zri_result);
 
@@ -1013,7 +1013,7 @@ zcp_eval_open(zcp_run_info_t *ri, const char *poolname)
 
 	error = dsl_pool_hold(poolname, FTAG, &dp);
 	if (error != 0) {
-		zcp_pool_error(ri, poolname);
+		zcp_pool_error(ri, poolname, error);
 		return;
 	}
 
@@ -1159,7 +1159,7 @@ zcp_eval(const char *poolname, const char *program, boolean_t sync,
 		err = dsl_sync_task_sig(poolname, NULL, zcp_eval_sync,
 		    zcp_eval_sig, &runinfo, 0, ZFS_SPACE_CHECK_ZCP_EVAL);
 		if (err != 0)
-			zcp_pool_error(&runinfo, poolname);
+			zcp_pool_error(&runinfo, poolname, err);
 	} else {
 		zcp_eval_open(&runinfo, poolname);
 	}