+ /* compatibility check for 2.10 clients when it tries to open mirrored
+ * files. 2.10 clients don't verify overlapping components so they
+ * would read and write mirrored files just as if they were normal
+ * PFL files, which will cause the problem that sycned mirrors actually
+ * contain different data.
+ * Older clients are not a concern here because they don't even
+ * understand PFL layout. */
+ if (isreg && !exp_connect_flr(exp) && ma->ma_valid & MA_LOV &&
+ mdt_lmm_is_flr(ma->ma_lmm)) {
+ /* LU-10286: for simplicity clients who don't understand
+ * mirrored layout(with connect flag OBD_CONNECT2_FLR) won't
+ * be able to open mirrored files */
+ RETURN(-EOPNOTSUPP);
+ }
+