diff --git a/block.c b/block.c
index f94585b230..814e5a02da 100644
--- a/block.c
+++ b/block.c
@@ -4010,17 +4010,11 @@ bool bdrv_unallocated_blocks_are_zero(BlockDriverState *bs)
 
 bool bdrv_can_write_zeroes_with_unmap(BlockDriverState *bs)
 {
-    BlockDriverInfo bdi;
-
     if (!(bs->open_flags & BDRV_O_UNMAP)) {
         return false;
     }
 
-    if (bdrv_get_info(bs, &bdi) == 0) {
-        return bdi.can_write_zeroes_with_unmap;
-    }
-
-    return false;
+    return bs->supported_zero_flags & BDRV_REQ_MAY_UNMAP;
 }
 
 const char *bdrv_get_encrypted_filename(BlockDriverState *bs)
diff --git a/block/crypto.c b/block/crypto.c
index 70e3691cd8..3df66947c5 100644
--- a/block/crypto.c
+++ b/block/crypto.c
@@ -576,7 +576,6 @@ static int block_crypto_get_info_luks(BlockDriverState *bs,
     }
 
     bdi->unallocated_blocks_are_zero = false;
-    bdi->can_write_zeroes_with_unmap = false;
     bdi->cluster_size = subbdi.cluster_size;
 
     return 0;
diff --git a/block/file-posix.c b/block/file-posix.c
index dd8d7cbbd2..ca49c1a98a 100644
--- a/block/file-posix.c
+++ b/block/file-posix.c
@@ -549,7 +549,6 @@ static int raw_open_common(BlockDriverState *bs, QDict *options,
 
     s->has_discard = true;
     s->has_write_zeroes = true;
-    bs->supported_zero_flags = BDRV_REQ_MAY_UNMAP;
     if ((bs->open_flags & BDRV_O_NOCACHE) != 0) {
         s->needs_alignment = true;
     }
@@ -599,6 +598,7 @@ static int raw_open_common(BlockDriverState *bs, QDict *options,
     }
 #endif
 
+    bs->supported_zero_flags = s->discard_zeroes ? BDRV_REQ_MAY_UNMAP : 0;
     ret = 0;
 fail:
     if (filename && (bdrv_flags & BDRV_O_TEMPORARY)) {
@@ -2223,7 +2223,6 @@ static int raw_get_info(BlockDriverState *bs, BlockDriverInfo *bdi)
     BDRVRawState *s = bs->opaque;
 
     bdi->unallocated_blocks_are_zero = s->discard_zeroes;
-    bdi->can_write_zeroes_with_unmap = s->discard_zeroes;
     return 0;
 }
 
diff --git a/block/iscsi.c b/block/iscsi.c
index 9f99ae5e07..421983dd6f 100644
--- a/block/iscsi.c
+++ b/block/iscsi.c
@@ -1877,7 +1877,6 @@ static int iscsi_open(BlockDriverState *bs, QDict *options, int flags,
     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 @@ static int iscsi_open(BlockDriverState *bs, QDict *options, int flags,
         }
     }
 
+    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 @@ static int iscsi_get_info(BlockDriverState *bs, BlockDriverInfo *bdi)
 {
     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;
 }
diff --git a/block/nbd.c b/block/nbd.c
index 411eeb42a7..ef81a9f53b 100644
--- a/block/nbd.c
+++ b/block/nbd.c
@@ -566,14 +566,6 @@ static void nbd_refresh_filename(BlockDriverState *bs, QDict *options)
     bs->full_open_options = opts;
 }
 
-static int nbd_get_info(BlockDriverState *bs, BlockDriverInfo *bdi)
-{
-    if (bs->supported_zero_flags & BDRV_REQ_MAY_UNMAP) {
-        bdi->can_write_zeroes_with_unmap = true;
-    }
-    return 0;
-}
-
 static BlockDriver bdrv_nbd = {
     .format_name                = "nbd",
     .protocol_name              = "nbd",
@@ -591,7 +583,6 @@ static BlockDriver bdrv_nbd = {
     .bdrv_detach_aio_context    = nbd_detach_aio_context,
     .bdrv_attach_aio_context    = nbd_attach_aio_context,
     .bdrv_refresh_filename      = nbd_refresh_filename,
-    .bdrv_get_info              = nbd_get_info,
 };
 
 static BlockDriver bdrv_nbd_tcp = {
@@ -611,7 +602,6 @@ static BlockDriver bdrv_nbd_tcp = {
     .bdrv_detach_aio_context    = nbd_detach_aio_context,
     .bdrv_attach_aio_context    = nbd_attach_aio_context,
     .bdrv_refresh_filename      = nbd_refresh_filename,
-    .bdrv_get_info              = nbd_get_info,
 };
 
 static BlockDriver bdrv_nbd_unix = {
@@ -631,7 +621,6 @@ static BlockDriver bdrv_nbd_unix = {
     .bdrv_detach_aio_context    = nbd_detach_aio_context,
     .bdrv_attach_aio_context    = nbd_attach_aio_context,
     .bdrv_refresh_filename      = nbd_refresh_filename,
-    .bdrv_get_info              = nbd_get_info,
 };
 
 static void bdrv_nbd_init(void)
diff --git a/block/qcow2.c b/block/qcow2.c
index a64a572785..801e29fc56 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -1479,7 +1479,7 @@ static int qcow2_do_open(BlockDriverState *bs, QDict *options, int flags,
 
     /* Initialise locks */
     qemu_co_mutex_init(&s->lock);
-    bs->supported_zero_flags = BDRV_REQ_MAY_UNMAP;
+    bs->supported_zero_flags = header.version >= 3 ? BDRV_REQ_MAY_UNMAP : 0;
 
     /* Repair image if dirty */
     if (!(flags & (BDRV_O_CHECK | BDRV_O_INACTIVE)) && !bs->read_only &&
@@ -3771,7 +3771,6 @@ static int qcow2_get_info(BlockDriverState *bs, BlockDriverInfo *bdi)
 {
     BDRVQcow2State *s = bs->opaque;
     bdi->unallocated_blocks_are_zero = true;
-    bdi->can_write_zeroes_with_unmap = (s->qcow_version >= 3);
     bdi->cluster_size = s->cluster_size;
     bdi->vm_state_offset = qcow2_vm_state_offset(s);
     return 0;
diff --git a/block/qed.c b/block/qed.c
index 205dbf16e3..c6ff3ab015 100644
--- a/block/qed.c
+++ b/block/qed.c
@@ -1438,7 +1438,6 @@ static int bdrv_qed_get_info(BlockDriverState *bs, BlockDriverInfo *bdi)
     bdi->cluster_size = s->header.cluster_size;
     bdi->is_dirty = s->header.features & QED_F_NEED_CHECK;
     bdi->unallocated_blocks_are_zero = true;
-    bdi->can_write_zeroes_with_unmap = true;
     return 0;
 }
 
diff --git a/include/block/block.h b/include/block/block.h
index 24ef816960..19b3ab9cb5 100644
--- a/include/block/block.h
+++ b/include/block/block.h
@@ -26,17 +26,6 @@ typedef struct BlockDriverInfo {
      * to the LBPRZ flag in the SCSI logical block provisioning page.
      */
     bool unallocated_blocks_are_zero;
-    /*
-     * True if the driver can optimize writing zeroes by unmapping
-     * sectors. This is equivalent to the BLKDISCARDZEROES ioctl in Linux
-     * with the difference that in qemu a discard is allowed to silently
-     * fail. Therefore we have to use bdrv_pwrite_zeroes with the
-     * BDRV_REQ_MAY_UNMAP flag for an optimized zero write with unmapping.
-     * After this call the driver has to guarantee that the contents read
-     * back as zero. It is additionally required that the block device is
-     * opened with BDRV_O_UNMAP flag for this to work.
-     */
-    bool can_write_zeroes_with_unmap;
     /*
      * True if this block driver only supports compressed writes
      */
diff --git a/tests/qemu-iotests/205 b/tests/qemu-iotests/205
index 10388920dc..e7b2eae51d 100644
--- a/tests/qemu-iotests/205
+++ b/tests/qemu-iotests/205
@@ -22,7 +22,7 @@ import os
 import sys
 import iotests
 import time
-from iotests import qemu_img, qemu_io, filter_qemu_io, QemuIoInteractive
+from iotests import qemu_img_create, qemu_io, filter_qemu_io, QemuIoInteractive
 
 nbd_sock = 'nbd_sock'
 nbd_uri = 'nbd+unix:///exp?socket=' + nbd_sock
@@ -31,7 +31,7 @@ disk = os.path.join(iotests.test_dir, 'disk')
 
 class TestNbdServerRemove(iotests.QMPTestCase):
     def setUp(self):
-        qemu_img('create', '-f', iotests.imgfmt, disk, '1M')
+        qemu_img_create('-f', iotests.imgfmt, disk, '1M')
 
         self.vm = iotests.VM().add_drive(disk)
         self.vm.launch()
diff --git a/tests/qemu-iotests/iotests.py b/tests/qemu-iotests/iotests.py
index 5a10b2d534..1bcc9ca57d 100644
--- a/tests/qemu-iotests/iotests.py
+++ b/tests/qemu-iotests/iotests.py
@@ -58,6 +58,11 @@ qemu_default_machine = os.environ.get('QEMU_DEFAULT_MACHINE')
 socket_scm_helper = os.environ.get('SOCKET_SCM_HELPER', 'socket_scm_helper')
 debug = False
 
+luks_default_secret_object = 'secret,id=keysec0,data=' + \
+                             os.environ['IMGKEYSECRET']
+luks_default_key_secret_opt = 'key-secret=keysec0'
+
+
 def qemu_img(*args):
     '''Run qemu-img and return the exit code'''
     devnull = open('/dev/null', 'r+')
@@ -66,6 +71,25 @@ def qemu_img(*args):
         sys.stderr.write('qemu-img received signal %i: %s\n' % (-exitcode, ' '.join(qemu_img_args + list(args))))
     return exitcode
 
+def qemu_img_create(*args):
+    args = list(args)
+
+    # default luks support
+    if '-f' in args and args[args.index('-f') + 1] == 'luks':
+        if '-o' in args:
+            i = args.index('-o')
+            if 'key-secret' not in args[i + 1]:
+                args[i + 1].append(luks_default_key_secret_opt)
+                args.insert(i + 2, '--object')
+                args.insert(i + 3, luks_default_secret_object)
+        else:
+            args = ['-o', luks_default_key_secret_opt,
+                    '--object', luks_default_secret_object] + args
+
+    args.insert(0, 'create')
+
+    return qemu_img(*args)
+
 def qemu_img_verbose(*args):
     '''Run qemu-img without suppressing its output and return the exit code'''
     exitcode = subprocess.call(qemu_img_args + list(args))
@@ -263,6 +287,13 @@ class VM(qtest.QEMUQtestMachine):
         if opts:
             options.append(opts)
 
+        if format == 'luks' and 'key-secret' not in opts:
+            # default luks support
+            if luks_default_secret_object not in self._args:
+                self.add_object(luks_default_secret_object)
+
+            options.append(luks_default_key_secret_opt)
+
         self._args.append('-drive')
         self._args.append(','.join(options))
         self._num_drives += 1