From fe4f9428fc403fa8b99051f52d84ea5bd13f3855 Mon Sep 17 00:00:00 2001
From: Niels de Vos <ndevos@redhat.com>
Date: Mon, 18 Jun 2018 19:31:43 +0200
Subject: libfuse: add copy_file_range() support

Add support for the relatively new copy_file_range() syscall. Backend
filesystems can now implement an efficient way of cloning/duplicating
data ranges within files. See 'man 2 copy_file_range' for more details.
---
 lib/fuse.c | 63 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 63 insertions(+)

(limited to 'lib/fuse.c')

diff --git a/lib/fuse.c b/lib/fuse.c
index b88ef1a..946ae2f 100644
--- a/lib/fuse.c
+++ b/lib/fuse.c
@@ -2359,6 +2359,29 @@ int fuse_fs_fallocate(struct fuse_fs *fs, const char *path, int mode,
 		return -ENOSYS;
 }
 
+ssize_t fuse_fs_copy_file_range(struct fuse_fs *fs, 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)
+{
+	fuse_get_context()->private_data = fs->user_data;
+	if (fs->op.copy_file_range) {
+		if (fs->debug)
+			fprintf(stderr, "copy_file_range from %s:%llu to "
+			                "%s:%llu, length: %llu\n",
+				path_in,
+				(unsigned long long) off_in,
+				path_out,
+				(unsigned long long) off_out,
+				(unsigned long long) len);
+
+		return fs->op.copy_file_range(path_in, fi_in, off_in, path_out,
+					      fi_out, off_out, len, flags);
+	} else
+		return -ENOSYS;
+}
+
 static int is_open(struct fuse *f, fuse_ino_t dir, const char *name)
 {
 	struct node *node;
@@ -4290,6 +4313,45 @@ static void fuse_lib_fallocate(fuse_req_t req, fuse_ino_t ino, int mode,
 	reply_err(req, err);
 }
 
+static void fuse_lib_copy_file_range(fuse_req_t req, fuse_ino_t nodeid_in,
+				     off_t off_in, struct fuse_file_info *fi_in,
+				     fuse_ino_t nodeid_out, off_t off_out,
+				     struct fuse_file_info *fi_out, size_t len,
+				     int flags)
+{
+	struct fuse *f = req_fuse_prepare(req);
+	struct fuse_intr_data d;
+	char *path_in, *path_out;
+	int err;
+	ssize_t res;
+
+	err = get_path_nullok(f, nodeid_in, &path_in);
+	if (err) {
+		reply_err(req, err);
+		return;
+	}
+
+	err = get_path_nullok(f, nodeid_out, &path_out);
+	if (err) {
+		free_path(f, nodeid_in, path_in);
+		reply_err(req, err);
+		return;
+	}
+
+	fuse_prepare_interrupt(f, req, &d);
+	res = fuse_fs_copy_file_range(f->fs, path_in, fi_in, off_in, path_out,
+				      fi_out, off_out, len, flags);
+	fuse_finish_interrupt(f, req, &d);
+
+	if (res >= 0)
+		fuse_reply_write(req, res);
+	else
+		reply_err(req, res);
+
+	free_path(f, nodeid_in, path_in);
+	free_path(f, nodeid_out, path_out);
+}
+
 static int clean_delay(struct fuse *f)
 {
 	/*
@@ -4386,6 +4448,7 @@ static struct fuse_lowlevel_ops fuse_path_ops = {
 	.ioctl = fuse_lib_ioctl,
 	.poll = fuse_lib_poll,
 	.fallocate = fuse_lib_fallocate,
+	.copy_file_range = fuse_lib_copy_file_range,
 };
 
 int fuse_notify_poll(struct fuse_pollhandle *ph)
-- 
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