+static int loop_clr_fd(struct loop_device *lo)
+{
+ if (lo->lo_state != Lo_bound)
+ return -ENXIO;
+ /*
+ * If we've explicitly asked to tear down the loop device,
+ * and it has an elevated reference count, set it for auto-teardown when
+ * the last reference goes away. This stops $!~#$@ udev from
+ * preventing teardown because it decided that it needs to run blkid on
+ * the loopback device whenever they appear. xfstests is notorious for
+ * failing tests because blkid via udev races with a losetup
+ * <dev>/do something like mkfs/losetup -d <dev> causing the losetup -d
+ * command to fail with EBUSY.
+ */
+ if (atomic_read(&lo->lo_refcnt) > 1) {
+ lo->lo_flags |= LO_FLAGS_AUTOCLEAR;
+ mutex_unlock(&loop_ctl_mutex);
+ return 0;
+ }
+ lo->lo_state = Lo_rundown;
+
+ return __loop_clr_fd(lo);
+}
+