+
+#ifdef HAVE_BDI
+ /*
+ * 2.6.32 API change,
+ * Added backing_device_info (BDI) per super block interfaces. A BDI
+ * must be configured when using a non-device backed filesystem for
+ * proper writeback. This is not required for older pdflush kernels.
+ *
+ * NOTE: Linux read-ahead is disabled in favor of zfs read-ahead.
+ */
+ zsb->z_bdi.ra_pages = 0;
+ sb->s_bdi = &zsb->z_bdi;
+
+ error = -bdi_setup_and_register(&zsb->z_bdi, "zfs", BDI_CAP_MAP_COPY);
+ if (error)
+ goto out;
+#endif /* HAVE_BDI */