1 files changed, 82 insertions, 0 deletions
diff --git a/c_src/cmd_dump.c b/c_src/cmd_dump.c
index 5f354272..93e7d743 100644
--- a/c_src/cmd_dump.c
+++ b/c_src/cmd_dump.c
@@ -386,3 +386,85 @@ int cmd_dump(int argc, char *argv[])
 	darray_exit(&dev_names);
 	return ret;
 }
+
+static void undump_usage(void)
+{
+	puts("bcachefs undump - turn qcow2 images from 'bcachefs dump' back into sparse raw images\n"
+	     "Usage: bcachefs undump [OPTION]... <files>\n"
+	     "\n"
+	     "Options:\n"
+	     "  -f, --force     Force; overwrite when needed\n"
+	     "  -h, --help      Display this help and exit\n"
+	     "Report bugs to <linux-bcachefs@vger.kernel.org>");
+}
+
+struct undump {
+	char	*in, *out;
+	int	infd, outfd;
+};
+
+int cmd_undump(int argc, char *argv[])
+{
+	static const struct option longopts[] = {
+		{ "force",		no_argument,		NULL, 'f' },
+		{ "help",		no_argument,		NULL, 'h' },
+		{ NULL }
+	};
+	bool force = false;
+	int opt;
+
+	while ((opt = getopt_long(argc, argv, "fh",
+				  longopts, NULL)) != -1)
+		switch (opt) {
+		case 'f':
+			force = true;
+			break;
+		case 'h':
+			undump_usage();
+			exit(EXIT_SUCCESS);
+		}
+	args_shift(optind);
+
+	if (!argc) {
+		undump_usage();
+		die("Please supply file(s) to convert");
+	}
+
+	DARRAY(struct undump) files = {};
+
+	for (unsigned i = 0; i < argc; i++) {
+		unsigned len = strlen(argv[i]);
+		const char *suffix = ".qcow2";
+		unsigned suffixlen = strlen(suffix);
+
+		if (len <= suffixlen ||
+		    strcmp(suffix, argv[i] + len - suffixlen)) {
+			die("%s not a qcow2 image?", argv[i]);
+		}
+
+		char *out = strdup(argv[i]);
+		out[len - suffixlen] = '\0';
+
+		if (!force && !access(out, F_OK))
+			die("%s already exists", out);
+
+		darray_push(&files, ((struct undump) {
+			.in	= argv[i],
+			.out	= out,
+			.infd	= xopen(argv[i], O_RDONLY),
+		}));
+	}
+
+	darray_for_each(files, i)
+		i->outfd = xopen(i->out, O_WRONLY|O_CREAT|(!force ? O_EXCL : 0), 0600);
+
+	darray_for_each(files, i) {
+		qcow2_to_raw(i->infd, i->outfd);
+		close(i->infd);
+		close(i->outfd);
+		free(i->out);
+	}
+
+	darray_exit(&files);
+	return 0;
+}