[PATCH v4 2/7] qapi: Make parameter 'file' optional for BlockdevCreateOptionsLUKS

[yong.huang@smartx.com]

From: Hyman Huang <yong.huang@smartx.com>

To support detached LUKS header creation, make the existing 'file'
field in BlockdevCreateOptionsLUKS optional.

Signed-off-by: Hyman Huang <yong.huang@smartx.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
---
 block/crypto.c       | 21 ++++++++++++++-------
 qapi/block-core.json |  5 +++--
 2 files changed, 17 insertions(+), 9 deletions(-)

diff --git a/block/crypto.c b/block/crypto.c
index 68656158e9..e87dc84111 100644
--- a/block/crypto.c
+++ b/block/crypto.c
@@ -663,9 +663,9 @@ block_crypto_co_create_luks(BlockdevCreateOptions *create_options, Error **errp)
     assert(create_options->driver == BLOCKDEV_DRIVER_LUKS);
     luks_opts = &create_options->u.luks;
 
-    bs = bdrv_co_open_blockdev_ref(luks_opts->file, errp);
-    if (bs == NULL) {
-        return -EIO;
+    if (luks_opts->file == NULL) {
+        error_setg(errp, "Formatting LUKS disk requires parameter 'file'");
+        return -EINVAL;
     }
 
     create_opts = (QCryptoBlockCreateOptions) {
@@ -677,10 +677,17 @@ block_crypto_co_create_luks(BlockdevCreateOptions *create_options, Error **errp)
         preallocation = luks_opts->preallocation;
     }
 
-    ret = block_crypto_co_create_generic(bs, luks_opts->size, &create_opts,
-                                         preallocation, errp);
-    if (ret < 0) {
-        goto fail;
+    if (luks_opts->file) {
+        bs = bdrv_co_open_blockdev_ref(luks_opts->file, errp);
+        if (bs == NULL) {
+            return -EIO;
+        }
+
+        ret = block_crypto_co_create_generic(bs, luks_opts->size, &create_opts,
+                                             preallocation, errp);
+        if (ret < 0) {
+            goto fail;
+        }
     }
 
     ret = 0;
diff --git a/qapi/block-core.json b/qapi/block-core.json
index ae604c6019..69a88d613d 100644
--- a/qapi/block-core.json
+++ b/qapi/block-core.json
@@ -4957,7 +4957,8 @@
 #
 # Driver specific image creation options for LUKS.
 #
-# @file: Node to create the image format on
+# @file: Node to create the image format on, mandatory except when
+#        'preallocation' is not requested
 #
 # @size: Size of the virtual disk in bytes
 #
@@ -4968,7 +4969,7 @@
 ##
 { 'struct': 'BlockdevCreateOptionsLUKS',
   'base': 'QCryptoBlockCreateOptionsLUKS',
-  'data': { 'file':             'BlockdevRef',
+  'data': { '*file':            'BlockdevRef',
             'size':             'size',
             '*preallocation':   'PreallocMode' } }
 
-- 
2.31.1