switch (opt) {
        case OPT_SOURCE:
                if (fc->source)
-                       return invalf(fc, "fuse: Multiple sources specified");
+                       return invalfc(fc, "Multiple sources specified");
                fc->source = param->string;
                param->string = NULL;
                break;
 
        case OPT_SUBTYPE:
                if (ctx->subtype)
-                       return invalf(fc, "fuse: Multiple subtypes specified");
+                       return invalfc(fc, "Multiple subtypes specified");
                ctx->subtype = param->string;
                param->string = NULL;
                return 0;
 
        case OPT_ROOTMODE:
                if (!fuse_valid_type(result.uint_32))
-                       return invalf(fc, "fuse: Invalid rootmode");
+                       return invalfc(fc, "Invalid rootmode");
                ctx->rootmode = result.uint_32;
                ctx->rootmode_present = 1;
                break;
        case OPT_USER_ID:
                ctx->user_id = make_kuid(fc->user_ns, result.uint_32);
                if (!uid_valid(ctx->user_id))
-                       return invalf(fc, "fuse: Invalid user_id");
+                       return invalfc(fc, "Invalid user_id");
                ctx->user_id_present = 1;
                break;
 
        case OPT_GROUP_ID:
                ctx->group_id = make_kgid(fc->user_ns, result.uint_32);
                if (!gid_valid(ctx->group_id))
-                       return invalf(fc, "fuse: Invalid group_id");
+                       return invalfc(fc, "Invalid group_id");
                ctx->group_id_present = 1;
                break;
 
 
        case OPT_BLKSIZE:
                if (!ctx->is_bdev)
-                       return invalf(fc, "fuse: blksize only supported for fuseblk");
+                       return invalfc(fc, "blksize only supported for fuseblk");
                ctx->blksize = result.uint_32;
                break;