fuse: add missing FR_FORCE

commit 2e38bea9 upstream.

fuse_file_put() was missing the "force" flag for the RELEASE request when
sending synchronously (fuseblk).

If this flag is not set, then a sync request may be interrupted before it
is dequeued by the userspace filesystem.  In this case the OPEN won't be
balanced with a RELEASE.

[js] force is a variable, not a bit
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Fixes: 5a18ec17 ("fuse: fix hang of single threaded fuseblk filesystem")
Signed-off-by: Jiri Slaby <jslaby@suse.cz>

fs/fuse/file.c

@@ -128,6 +128,7 @@ static void fuse_file_put(struct fuse_file *ff, bool sync)
 		struct fuse_req *req = ff->reserved_req;
 
 		if (sync) {
+			req->force = 1;
 			req->background = 0;
 			fuse_request_send(ff->fc, req);
 			path_put(&req->misc.release.path);