diff --git a/block/iscsi.c b/block/iscsi.c
index 9f99ae5..421983d 100644
--- a/block/iscsi.c
+++ b/block/iscsi.c
@@ -1877,7 +1877,6 @@
     if (iscsilun->dpofua) {
         bs->supported_write_flags = BDRV_REQ_FUA;
     }
-    bs->supported_zero_flags = BDRV_REQ_MAY_UNMAP;
 
     /* Check the write protect flag of the LUN if we want to write */
     if (iscsilun->type == TYPE_DISK && (flags & BDRV_O_RDWR) &&
@@ -1961,6 +1960,10 @@
         }
     }
 
+    if (iscsilun->lbprz && iscsilun->lbp.lbpws) {
+        bs->supported_zero_flags = BDRV_REQ_MAY_UNMAP;
+    }
+
 out:
     qemu_opts_del(opts);
     g_free(initiator_name);
@@ -2160,7 +2163,6 @@
 {
     IscsiLun *iscsilun = bs->opaque;
     bdi->unallocated_blocks_are_zero = iscsilun->lbprz;
-    bdi->can_write_zeroes_with_unmap = iscsilun->lbprz && iscsilun->lbp.lbpws;
     bdi->cluster_size = iscsilun->cluster_sectors * BDRV_SECTOR_SIZE;
     return 0;
 }