[PATCH 0/2] xfstests: add cifs.ko server-side copy helper

[David Disseldorp]

In preparation for adding cifs.ko support to xfstests, this patch series
extends the cloner binary to support SMB2 server-side copies via
CIFS_IOC_COPYCHUNK_FILE, in addition to the existing Btrfs COW clone
functionality.

This could be split into a separate binary if deemed necessary, but
given the code overlap, I though it suitable to share the same source.

Feedback appreciated.

--

David Disseldorp (2):
src/cloner: check filesystem type
src/cloner: add CIFS_IOC_COPYCHUNK_FILE support

configure.ac | 1 +
src/cloner.c | 123 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++----------
2 files changed, 114 insertions(+), 10 deletions(-)

[David Disseldorp]

Limit clone requests to Btrfs only for the moment.

Signed-off-by: David Disseldorp <***@suse.de>
---
src/cloner.c | 47 +++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 47 insertions(+)

diff --git a/src/cloner.c b/src/cloner.c
index ccc2354..6fb40fa 100644
--- a/src/cloner.c
+++ b/src/cloner.c
@@ -22,6 +22,7 @@
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/ioctl.h>
+#include <sys/vfs.h>
#include <stdint.h>
#include <stdbool.h>
#include <fcntl.h>
@@ -30,6 +31,7 @@
#include <stdio.h>
#include <string.h>
#include <errno.h>
+#include <linux/magic.h>
#ifdef HAVE_BTRFS_IOCTL_H
#include <btrfs/ioctl.h>
#else
@@ -47,6 +49,10 @@ struct btrfs_ioctl_clone_range_args {
struct btrfs_ioctl_clone_range_args)
#endif

+#ifndef BTRFS_SUPER_MAGIC
+#define BTRFS_SUPER_MAGIC 0x9123683E
+#endif
+
static void
usage(char *name, const char *msg)
{
@@ -89,6 +95,41 @@ clone_file_range(int src_fd, int dst_fd, uint64_t src_off, uint64_t dst_off,
return ret;
}

+static int
+cloner_check_fs_support(int src_fd, int dest_fd, unsigned int *fs_type)
+{
+ int ret;
+ struct statfs sfs;
+
+ ret = fstatfs(src_fd, &sfs);
+ if (ret != 0) {
+ printf("failed to stat source FS\n");
+ return errno;
+ }
+
+ if (sfs.f_type != BTRFS_SUPER_MAGIC) {
+ printf("unsupported source FS 0x%x\n",
+ (unsigned int)sfs.f_type);
+ return ENOTSUP;
+ }
+
+ *fs_type = (unsigned int)sfs.f_type;
+
+ ret = fstatfs(dest_fd, &sfs);
+ if (ret != 0) {
+ printf("failed to stat destination FS\n");
+ return errno;
+ }
+
+ if (sfs.f_type != *fs_type) {
+ printf("dest FS type 0x%x does not match source 0x%x\n",
+ (unsigned int)sfs.f_type, *fs_type);
+ return ENOTSUP;
+ }
+
+ return 0;
+}
+
int
main(int argc, char **argv)
{
@@ -102,6 +143,7 @@ main(int argc, char **argv)
int dst_fd;
int ret;
int opt;
+ unsigned int fs_type = 0;

while ((opt = getopt(argc, argv, "s:d:l:")) != -1) {
char *sval_end;
@@ -162,6 +204,11 @@ main(int argc, char **argv)
goto err_src_close;
}

+ ret = cloner_check_fs_support(src_fd, dst_fd, &fs_type);
+ if (ret != 0) {
+ goto err_dst_close;
+ }
+
if (full_file) {
ret = clone_file(src_fd, dst_fd);
} else {

[David Disseldorp]

cifs.ko supports server-side copy offloads via CIFS_IOC_COPYCHUNK_FILE.
In handling the ioctl, the request is split into a series of
SMB2 FSCTL_SRV_COPYCHUNK wire requests, which may be handled by the SMB
server as a local read/write, or COW clone as is the case for Samba with
vfs_btrfs.

Signed-off-by: David Disseldorp <***@suse.de>
---
configure.ac | 1 +
src/cloner.c | 78 +++++++++++++++++++++++++++++++++++++++++++++++++++---------
2 files changed, 68 insertions(+), 11 deletions(-)

diff --git a/configure.ac b/configure.ac
index 53459d8..d038f95 100644
--- a/configure.ac
+++ b/configure.ac
@@ -31,6 +31,7 @@ AC_HEADER_STDC
sys/fs/xfs_itable.h \
xfs/platform_defs.h \
btrfs/ioctl.h \
+ cifs/ioctl.h \
])

AC_CHECK_HEADERS([xfs/xfs_log_format.h],,,[#include <xfs/libxfs.h>])
diff --git a/src/cloner.c b/src/cloner.c
index 6fb40fa..18c44b9 100644
--- a/src/cloner.c
+++ b/src/cloner.c
@@ -1,6 +1,5 @@
/*
- * Tiny program to perform file (range) clones using raw Btrfs ioctls.
- * It should only be needed until btrfs-progs has an xfs_io equivalent.
+ * Tiny program to perform file (range) clones using raw Btrfs and CIFS ioctls.
*
* Copyright (C) 2014 SUSE Linux Products GmbH. All Rights Reserved.
*
@@ -49,9 +48,21 @@ struct btrfs_ioctl_clone_range_args {
struct btrfs_ioctl_clone_range_args)
#endif

+#ifdef HAVE_CIFS_IOCTL_H
+#include <cifs/ioctl.h>
+#else
+
+#define CIFS_IOCTL_MAGIC 0xCF
+#define CIFS_IOC_COPYCHUNK_FILE _IOW(CIFS_IOCTL_MAGIC, 3, int)
+
+#endif
+
#ifndef BTRFS_SUPER_MAGIC
#define BTRFS_SUPER_MAGIC 0x9123683E
#endif
+#ifndef CIFS_MAGIC_NUMBER
+#define CIFS_MAGIC_NUMBER 0xFE534D42
+#endif

static void
usage(char *name, const char *msg)
@@ -59,17 +70,19 @@ 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"
+ "\tA full file clone is performed by default, "
+ "unless any of the following are specified (Btrfs only):\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",
+ "\t-l <length>: length of clone (default = 0)\n\n"
+ "\tBoth Btrfs and CIFS are supported. On Btrfs, a COW clone "
+ "is attempted. On CIFS, a server-side copy is requested.\n",
msg, name);
_exit(1);
}

static int
-clone_file(int src_fd, int dst_fd)
+clone_file_btrfs(int src_fd, int dst_fd)
{
int ret = ioctl(dst_fd, BTRFS_IOC_CLONE, src_fd);
if (ret != 0)
@@ -78,8 +91,33 @@ clone_file(int src_fd, int dst_fd)
}

static int
-clone_file_range(int src_fd, int dst_fd, uint64_t src_off, uint64_t dst_off,
- uint64_t len)
+clone_file_cifs(int src_fd, int dst_fd)
+{
+ int ret = ioctl(dst_fd, CIFS_IOC_COPYCHUNK_FILE, src_fd);
+ if (ret != 0)
+ ret = errno;
+ return ret;
+}
+
+static int
+clone_file(unsigned int fs_type, int src_fd, int dst_fd)
+{
+ switch (fs_type) {
+ case BTRFS_SUPER_MAGIC:
+ return clone_file_btrfs(src_fd, dst_fd);
+ break;
+ case CIFS_MAGIC_NUMBER:
+ return clone_file_cifs(src_fd, dst_fd);
+ break;
+ default:
+ return ENOTSUP;
+ break;
+ }
+}
+
+static int
+clone_file_range_btrfs(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;
@@ -96,6 +134,22 @@ clone_file_range(int src_fd, int dst_fd, uint64_t src_off, uint64_t dst_off,
}

static int
+clone_file_range(unsigned int fs_type, int src_fd, int dst_fd, uint64_t src_off,
+ uint64_t dst_off, uint64_t len)
+{
+ switch (fs_type) {
+ case BTRFS_SUPER_MAGIC:
+ return clone_file_range_btrfs(src_fd, dst_fd, src_off, dst_off,
+ len);
+ break;
+ case CIFS_MAGIC_NUMBER: /* only supports full file server-side copies */
+ default:
+ return ENOTSUP;
+ break;
+ }
+}
+
+static int
cloner_check_fs_support(int src_fd, int dest_fd, unsigned int *fs_type)
{
int ret;
@@ -107,7 +161,8 @@ cloner_check_fs_support(int src_fd, int dest_fd, unsigned int *fs_type)
return errno;
}

- if (sfs.f_type != BTRFS_SUPER_MAGIC) {
+ if ((sfs.f_type != BTRFS_SUPER_MAGIC)
+ && (sfs.f_type != CIFS_MAGIC_NUMBER)) {
printf("unsupported source FS 0x%x\n",
(unsigned int)sfs.f_type);
return ENOTSUP;
@@ -210,9 +265,10 @@ main(int argc, char **argv)
}

if (full_file) {
- ret = clone_file(src_fd, dst_fd);
+ ret = clone_file(fs_type, src_fd, dst_fd);
} else {
- ret = clone_file_range(src_fd, dst_fd, src_off, dst_off, len);
+ ret = clone_file_range(fs_type, src_fd, dst_fd, src_off,
+ dst_off, len);
}
if (ret != 0) {
printf("clone failed: %s\n", strerror(ret));