passthrough_ll: pass correct errno to fuse_reply_err()

fuse_reply_err() expects the error code, not its negative.

Upstreamed from https://www.redhat.com/archives/virtio-fs/2020-January/msg00000.html. Original commit message:

lo_copy_file_range() passes -errno to fuse_reply_err() and then fuse_reply_err()
changes it to errno again, so that subsequent fuse_send_reply_iov_nofree() catches
the wrong errno.(i.e. reports "fuse: bad error value: ...").

Make fuse_send_reply_iov_nofree() accept the correct -errno by passing errno
directly in lo_copy_file_range().

Signed-off-by: Xiao Yang <yangx.jy@cn.fujitsu.com>
Reviewed-by: Eryu Guan <eguan@linux.alibaba.com>
Co-authored-by: Xiao Yang <ice_yangxiao@163.com>

diff --git a/example/passthrough_ll.c b/example/passthrough_ll.c
index 5372d02934a6458cf01ef8948efe463394ef86e4..d80b493c8016d1291ae7631e9deb65147300092a 100644 (file)
--- a/example/passthrough_ll.c
+++ b/example/passthrough_ll.c
@@ -1155,7 +1155,7 @@ static void lo_copy_file_range(fuse_req_t req, fuse_ino_t ino_in, off_t off_in,
        res = copy_file_range(fi_in->fh, &off_in, fi_out->fh, &off_out, len,
                              flags);
        if (res < 0)
-               fuse_reply_err(req, -errno);
+               fuse_reply_err(req, errno);
        else
                fuse_reply_write(req, res);
 }