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.
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Fixes: 5a18ec176c93 ("fuse: fix hang of single threaded fuseblk filesystem") Cc: <stable@vger.kernel.org> # v2.6.38+