examples: add copy_file_range() support to passthrough(_fh)

The passthrough example filesystem can be used for validating the API
and the implementation in the FUSE kernel module.

ChangeLog.rst

@@ -1,3 +1,9 @@
+libfuse 3.4.0
+=============
+
+* Add `copy_file_range()` to support efficient copying of data from one file to
+  an other.
+
 libfuse 3.3.0 (2018-11-06)
 ==========================
 

example/passthrough.c

@@ -29,6 +29,8 @@
 #include <config.h>
 #endif
 
+#define _GNU_SOURCE
+
 #ifdef linux
 /* For pread()/pwrite()/utimensat() */
 #define _XOPEN_SOURCE 700
@@ -445,6 +447,46 @@ static int xmp_removexattr(const char *path, const char *name)
 }
 #endif /* HAVE_SETXATTR */
 
+#ifdef HAVE_COPY_FILE_RANGE
+static ssize_t xmp_copy_file_range(const char *path_in,
+				   struct fuse_file_info *fi_in,
+				   off_t offset_in, const char *path_out,
+				   struct fuse_file_info *fi_out,
+				   off_t offset_out, size_t len, int flags)
+{
+	int fd_in, fd_out;
+	ssize_t res;
+
+	if(fi_in == NULL)
+		fd_in = open(path_in, O_RDONLY);
+	else
+		fd_in = fi_in->fh;
+
+	if (fd_in == -1)
+		return -errno;
+
+	if(fi_out == NULL)
+		fd_out = open(path_out, O_WRONLY);
+	else
+		fd_out = fi_out->fh;
+
+	if (fd_out == -1) {
+		close(fd_in);
+		return -errno;
+	}
+
+	res = copy_file_range(fd_in, &offset_in, fd_out, &offset_out, len,
+			      flags);
+	if (res == -1)
+		res = -errno;
+
+	close(fd_in);
+	close(fd_out);
+
+	return res;
+}
+#endif
+
 static struct fuse_operations xmp_oper = {
 	.init           = xmp_init,
 	.getattr	= xmp_getattr,
@@ -480,6 +522,9 @@ static struct fuse_operations xmp_oper = {
 	.listxattr	= xmp_listxattr,
 	.removexattr	= xmp_removexattr,
 #endif
+#ifdef HAVE_COPY_FILE_RANGE
+	.copy_file_range = xmp_copy_file_range,
+#endif
 };
 
 int main(int argc, char *argv[])

example/passthrough_fh.c

@@ -576,6 +576,26 @@ static int xmp_flock(const char *path, struct fuse_file_info *fi, int op)
 	return 0;
 }
 
+#ifdef HAVE_COPY_FILE_RANGE
+static ssize_t xmp_copy_file_range(const char *path_in,
+				   struct fuse_file_info *fi_in,
+				   off_t off_in, const char *path_out,
+				   struct fuse_file_info *fi_out,
+				   off_t off_out, size_t len, int flags)
+{
+	ssize_t res;
+	(void) path_in;
+	(void) path_out;
+
+	res = copy_file_range(fi_in->fh, &off_in, fi_out->fh, &off_out, len,
+			      flags);
+	if (res == -1)
+		return -errno;
+
+	return res;
+}
+#endif
+
 static struct fuse_operations xmp_oper = {
 	.init           = xmp_init,
 	.getattr	= xmp_getattr,
@@ -620,6 +640,9 @@ static struct fuse_operations xmp_oper = {
 	.lock		= xmp_lock,
 #endif
 	.flock		= xmp_flock,
+#ifdef HAVE_COPY_FILE_RANGE
+	.copy_file_range = xmp_copy_file_range,
+#endif
 };
 
 int main(int argc, char *argv[])

example/passthrough_ll.c

@@ -37,6 +37,8 @@
 #define _GNU_SOURCE
 #define FUSE_USE_VERSION 31
 
+#include "config.h"
+
 #include <fuse_lowlevel.h>
 #include <unistd.h>
 #include <stdlib.h>
@@ -1121,6 +1123,31 @@ out:
 	fuse_reply_err(req, saverr);
 }
 
+#ifdef HAVE_COPY_FILE_RANGE
+static void lo_copy_file_range(fuse_req_t req, fuse_ino_t ino_in, off_t off_in,
+			       struct fuse_file_info *fi_in,
+			       fuse_ino_t ino_out, off_t off_out,
+			       struct fuse_file_info *fi_out, size_t len,
+			       int flags)
+{
+	ssize_t res;
+
+	if (lo_debug(req))
+		fprintf(stderr, "lo_copy_file_range(ino=%" PRIu64 "/fd=%lu, "
+				"off=%lu, ino=%" PRIu64 "/fd=%lu, "
+				"off=%lu, size=%zd, flags=0x%x)\n",
+			ino_in, fi_in->fh, off_in, ino_out, fi_out->fh, off_out,
+			len, flags);
+
+	res = copy_file_range(fi_in->fh, &off_in, fi_out->fh, &off_out, len,
+			      flags);
+	if (res < 0)
+		fuse_reply_err(req, -errno);
+	else
+		fuse_reply_write(req, res);
+}
+#endif
+
 static struct fuse_lowlevel_ops lo_oper = {
 	.init		= lo_init,
 	.lookup		= lo_lookup,
@@ -1155,6 +1182,9 @@ static struct fuse_lowlevel_ops lo_oper = {
 	.listxattr	= lo_listxattr,
 	.setxattr	= lo_setxattr,
 	.removexattr	= lo_removexattr,
+#ifdef HAVE_COPY_FILE_RANGE
+	.copy_file_range = lo_copy_file_range,
+#endif
 };
 
 int main(int argc, char *argv[])

lib/meson.build

@@ -32,7 +32,7 @@ libfuse = library('fuse3', libfuse_sources, version: meson.project_version(),
                   soversion: '3', include_directories: include_dirs,
                   dependencies: deps, install: true,
                   link_depends: 'fuse_versionscript',
-                  c_args: [ '-DFUSE_USE_VERSION=33',
+                  c_args: [ '-DFUSE_USE_VERSION=34',
                             '-DFUSERMOUNT_DIR="@0@"'.format(fusermount_path) ],
                   link_args: ['-Wl,--version-script,' + meson.current_source_dir()
                               + '/fuse_versionscript' ])

meson.build

@@ -1,4 +1,4 @@
-project('libfuse3', 'c', version: '3.3.0',
+project('libfuse3', 'c', version: '3.4.0',
         meson_version: '>= 0.42',
         default_options: [ 'buildtype=debugoptimized' ])
 
@@ -36,7 +36,7 @@ cfg.set_quoted('PACKAGE_VERSION', meson.project_version())
 # Test for presence of some functions
 test_funcs = [ 'fork', 'fstatat', 'openat', 'readlinkat', 'pipe2',
                'splice', 'vmsplice', 'posix_fallocate', 'fdatasync',
-               'utimensat' ]
+               'utimensat', 'copy_file_range' ]
 foreach func : test_funcs
     cfg.set('HAVE_' + func.to_upper(),
         cc.has_function(func, prefix: include_default, args: args_default))

util/meson.build

@@ -11,7 +11,7 @@ executable('mount.fuse3', ['mount.fuse.c'],
            link_with: [ libfuse ],
            install: true,
            install_dir: get_option('sbindir'),
-           c_args: '-DFUSE_USE_VERSION=33')
+           c_args: '-DFUSE_USE_VERSION=34')
 
 
 udevrulesdir = get_option('udevrulesdir')