btrfs: add small program for clone testing

The cloner program is capable of cloning files using the BTRFS_IOC_CLONE
and BTRFS_IOC_CLONE_RANGE ioctls.

Signed-off-by: David Disseldorp <ddiss@suse.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>

.gitignore

@@ -104,6 +104,7 @@
 /src/aio-dio-regress/aio-free-ring-with-bogus-nr-pages
 /src/aio-dio-regress/aio-io-setup-with-nonwritable-context-pointer
 /src/aio-dio-regress/aiodio_sparse2
+/src/cloner
 
 # dmapi/ binaries
 /dmapi/src/common/cmd/read_invis

src/Makefile

@@ -18,7 +18,7 @@ LINUX_TARGETS = xfsctl bstat t_mtab getdevicesize preallo_rw_pattern_reader \
 	locktest unwritten_mmap bulkstat_unlink_test t_stripealign \
 	bulkstat_unlink_test_modified t_dir_offset t_futimens t_immutable \
 	stale_handle pwrite_mmap_blocked t_dir_offset2 seek_sanity_test \
-	seek_copy_test t_readdir_1 t_readdir_2 fsync-tester nsexec
+	seek_copy_test t_readdir_1 t_readdir_2 fsync-tester nsexec cloner
 
 SUBDIRS =
 

src/cloner.c

@@ -0,0 +1,188 @@
+/*
+ *  Tiny program to perform file (range) clones using raw Btrfs ioctls.
+ *  It should only be needed until btrfs-progs has an xfs_io equivalent.
+ *
+ *  Copyright (C) 2014 SUSE Linux Products GmbH. All Rights Reserved.
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; if not, write to the Free Software
+ *  Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
+ */
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/ioctl.h>
+#include <stdint.h>
+#include <stdbool.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <errno.h>
+
+struct btrfs_ioctl_clone_range_args {
+	int64_t src_fd;
+	uint64_t src_offset;
+	uint64_t src_length;
+	uint64_t dest_offset;
+};
+
+#define BTRFS_IOCTL_MAGIC 0x94
+#define BTRFS_IOC_CLONE       _IOW(BTRFS_IOCTL_MAGIC, 9, int)
+#define BTRFS_IOC_CLONE_RANGE _IOW(BTRFS_IOCTL_MAGIC, 13, \
+				   struct btrfs_ioctl_clone_range_args)
+
+static void
+usage(char *name, const char *msg)
+{
+	printf("Fatal: %s\n"
+	       "Usage:\n"
+	       "%s [options] <src_file> <dest_file>\n"
+	       "\tA full file clone (reflink) is performed by default, "
+	       "unless any of the following are specified:\n"
+	       "\t-s <offset>:	source file offset (default = 0)\n"
+	       "\t-d <offset>:	destination file offset (default = 0)\n"
+	       "\t-l <length>:	length of clone (default = 0)\n",
+	       msg, name);
+	_exit(1);
+}
+
+static int
+clone_file(int src_fd, int dst_fd)
+{
+	int ret = ioctl(dst_fd, BTRFS_IOC_CLONE, src_fd);
+	if (ret != 0)
+		ret = errno;
+	return ret;
+}
+
+static int
+clone_file_range(int src_fd, int dst_fd, uint64_t src_off, uint64_t dst_off,
+		 uint64_t len)
+{
+	struct btrfs_ioctl_clone_range_args cr_args;
+	int ret;
+
+	memset(&cr_args, 0, sizeof(cr_args));
+	cr_args.src_fd = src_fd;
+	cr_args.src_offset = src_off;
+	cr_args.src_length = len;
+	cr_args.dest_offset = dst_off;
+	ret = ioctl(dst_fd, BTRFS_IOC_CLONE_RANGE, &cr_args);
+	if (ret != 0)
+		ret = errno;
+	return ret;
+}
+
+int
+main(int argc, char **argv)
+{
+	bool full_file = true;
+	uint64_t src_off = 0;
+	uint64_t dst_off = 0;
+	uint64_t len = 0;
+	char *src_file;
+	int src_fd;
+	char *dst_file;
+	int dst_fd;
+	int ret;
+	int opt;
+
+	while ((opt = getopt(argc, argv, "s:d:l:")) != -1) {
+		char *sval_end;
+		switch (opt) {
+		case 's':
+			errno = 0;
+			src_off = strtoull(optarg, &sval_end, 10);
+			if ((errno) || (*sval_end != '\0'))
+				usage(argv[0], "invalid source offset");
+			full_file = false;
+			break;
+		case 'd':
+			errno = 0;
+			dst_off = strtoull(optarg, &sval_end, 10);
+			if ((errno) || (*sval_end != '\0'))
+				usage(argv[0], "invalid destination offset");
+			full_file = false;
+			break;
+		case 'l':
+			errno = 0;
+			len = strtoull(optarg, &sval_end, 10);
+			if ((errno) || (*sval_end != '\0'))
+				usage(argv[0], "invalid length");
+			full_file = false;
+			break;
+		default:
+			usage(argv[0], "invalid argument");
+		}
+	}
+
+	/* should be exactly two args left */
+	if (optind != argc - 2)
+		usage(argv[0], "src_file and dst_file arguments are madatory");
+
+	src_file = (char *)strdup(argv[optind++]);
+	if (src_file == NULL) {
+		ret = ENOMEM;
+		printf("no memory\n");
+		goto err_out;
+	}
+	dst_file = (char *)strdup(argv[optind++]);
+	if (dst_file == NULL) {
+		ret = ENOMEM;
+		printf("no memory\n");
+		goto err_src_free;
+	}
+
+	src_fd = open(src_file, O_RDONLY);
+	if (src_fd == -1) {
+		ret = errno;
+		printf("failed to open %s: %s\n", src_file, strerror(errno));
+		goto err_dst_free;
+	}
+	dst_fd = open(dst_file, O_CREAT | O_WRONLY, 0644);
+	if (dst_fd == -1) {
+		ret = errno;
+		printf("failed to open %s: %s\n", dst_file, strerror(errno));
+		goto err_src_close;
+	}
+
+	if (full_file) {
+		ret = clone_file(src_fd, dst_fd);
+	} else {
+		ret = clone_file_range(src_fd, dst_fd, src_off, dst_off, len);
+	}
+	if (ret != 0) {
+		printf("clone failed: %s\n", strerror(ret));
+		goto err_dst_close;
+	}
+
+	ret = 0;
+err_dst_close:
+	if (close(dst_fd)) {
+		ret |= errno;
+		printf("failed to close dst file: %s\n", strerror(errno));
+	}
+err_src_close:
+	if (close(src_fd)) {
+		ret |= errno;
+		printf("failed to close src file: %s\n", strerror(errno));
+	}
+err_dst_free:
+	free(dst_file);
+err_src_free:
+	free(src_file);
+err_out:
+	return ret;
+}