diff mbox

[1/2] btrfs: add small program for clone testing

Message ID 1391599009-2402-2-git-send-email-ddiss@suse.de (mailing list archive)
State New, archived
Headers show

Commit Message

David Disseldorp Feb. 5, 2014, 11:16 a.m. UTC
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>
---
 src/Makefile |   2 +-
 src/cloner.c | 168 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 169 insertions(+), 1 deletion(-)
 create mode 100644 src/cloner.c

Comments

Dave Chinner Feb. 5, 2014, 11:09 p.m. UTC | #1
On Wed, Feb 05, 2014 at 12:16:48PM +0100, David Disseldorp wrote:
> 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>

Hi Dave - long time since I've seen your head pop up around here ;)

A few comments below.

> +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)

Is there some published header file that these belong to? i.e.
somewhere in the include/linux/uapi/ kernel directory? Normally the
way to handle this sort of thing is by autoconf - if the header file
exists, then we include it, otherwise we use the manual definitions.
This just means that if the public api ever changes, we'll pick it
up automatically in future...

> +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) {
> +		switch (opt) {
> +		case 's':
> +			src_off = atoi(optarg);

atoi() only returns 32 bit numbers. You probably should use
strtoull() as the offset parameters are 64 bit.

Cheers,

Dave.
David Disseldorp Feb. 6, 2014, 10:03 a.m. UTC | #2
Hi Dave,

On Thu, 6 Feb 2014 10:09:36 +1100, Dave Chinner wrote:

> On Wed, Feb 05, 2014 at 12:16:48PM +0100, David Disseldorp wrote:
> > 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>
> 
> Hi Dave - long time since I've seen your head pop up around here ;)

Indeed, it's been a while. Thanks for the review :)

> 
> A few comments below.
> 
> > +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)
> 
> Is there some published header file that these belong to? i.e.
> somewhere in the include/linux/uapi/ kernel directory? Normally the
> way to handle this sort of thing is by autoconf - if the header file
> exists, then we include it, otherwise we use the manual definitions.
> This just means that if the public api ever changes, we'll pick it
> up automatically in future...

I'd wanted to avoid the addition of another xfsqa prereq, but I guess
it'll work with the fall-back.
I'll add the autoconf logic to the next round, along with changes
addressing your other remarks.

Cheers, David
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diff mbox

Patch

diff --git a/src/Makefile b/src/Makefile
index 84c8297..6509f2d 100644
--- a/src/Makefile
+++ b/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 =
 
diff --git a/src/cloner.c b/src/cloner.c
new file mode 100644
index 0000000..59defbb
--- /dev/null
+++ b/src/cloner.c
@@ -0,0 +1,168 @@ 
+/*
+ *  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) {
+		switch (opt) {
+		case 's':
+			src_off = atoi(optarg);
+			full_file = false;
+			break;
+		case 'd':
+			dst_off = atoi(optarg);
+			full_file = false;
+			break;
+		case 'l':
+			len = atoi(optarg);
+			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;
+		goto err_out;
+	}
+	dst_file = (char *)strdup(argv[optind++]);
+	if (dst_file == NULL) {
+		ret = ENOMEM;
+		goto err_src_free;
+	}
+
+	src_fd = open(src_file, O_RDONLY);
+	if (src_fd == -1) {
+		ret = errno;
+		goto err_dst_free;
+	}
+	dst_fd = open(dst_file, O_CREAT | O_WRONLY, 0644);
+	if (dst_fd == -1) {
+		ret = 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 with %d\n", ret);
+		goto err_dst_close;
+	}
+
+	ret = 0;
+err_dst_close:
+	ret |= close(dst_fd);
+err_src_close:
+	ret |= close(src_fd);
+err_dst_free:
+	free(dst_file);
+err_src_free:
+	free(src_file);
+err_out:
+	return ret;
+}