[PATCH 18/19] block/qcow2: implement blockdev-amend

[Max Reitz <mreitz@redhat.com>]

From: Maxim Levitsky <mlevitsk@redhat.com>

Currently the implementation only supports amending the encryption
options, unlike the qemu-img version

Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-Id: <20200608094030.670121-14-mlevitsk@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
---
 qapi/block-core.json | 16 +++++++++++++++-
 block/qcow2.c        | 39 +++++++++++++++++++++++++++++++++++++++
 2 files changed, 54 insertions(+), 1 deletion(-)

diff --git a/qapi/block-core.json b/qapi/block-core.json
index cd679ad435..b20332e592 100644
--- a/qapi/block-core.json
+++ b/qapi/block-core.json
@@ -4686,6 +4686,19 @@
   'data': { }
 }
 
+##
+# @BlockdevAmendOptionsQcow2:
+#
+# Driver specific image amend options for qcow2.
+# For now, only encryption options can be amended
+#
+# @encrypt          Encryption options to be amended
+#
+# Since: 5.1
+##
+{ 'struct': 'BlockdevAmendOptionsQcow2',
+  'data': { '*encrypt':         'QCryptoBlockAmendOptions' } }
+
 ##
 # @BlockdevAmendOptions:
 #
@@ -4700,7 +4713,8 @@
       'driver':         'BlockdevDriver' },
   'discriminator': 'driver',
   'data': {
-      'luks':           'BlockdevAmendOptionsLUKS' } }
+      'luks':           'BlockdevAmendOptionsLUKS',
+      'qcow2':          'BlockdevAmendOptionsQcow2' } }
 
 ##
 # @x-blockdev-amend:
diff --git a/block/qcow2.c b/block/qcow2.c
index 0e72e8fc39..0d2d05d1f7 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -5585,6 +5585,44 @@ static int qcow2_amend_options(BlockDriverState *bs, QemuOpts *opts,
     return 0;
 }
 
+static int coroutine_fn qcow2_co_amend(BlockDriverState *bs,
+                                       BlockdevAmendOptions *opts,
+                                       bool force,
+                                       Error **errp)
+{
+    BlockdevAmendOptionsQcow2 *qopts = &opts->u.qcow2;
+    BDRVQcow2State *s = bs->opaque;
+    int ret = 0;
+
+    if (qopts->has_encrypt) {
+        if (!s->crypto) {
+            error_setg(errp, "image is not encrypted, can't amend");
+            return -EOPNOTSUPP;
+        }
+
+        if (qopts->encrypt->format != Q_CRYPTO_BLOCK_FORMAT_LUKS) {
+            error_setg(errp,
+                       "Amend can't be used to change the qcow2 encryption format");
+            return -EOPNOTSUPP;
+        }
+
+        if (s->crypt_method_header != QCOW_CRYPT_LUKS) {
+            error_setg(errp,
+                       "Only LUKS encryption options can be amended for qcow2 with blockdev-amend");
+            return -EOPNOTSUPP;
+        }
+
+        ret = qcrypto_block_amend_options(s->crypto,
+                                          qcow2_crypto_hdr_read_func,
+                                          qcow2_crypto_hdr_write_func,
+                                          bs,
+                                          qopts->encrypt,
+                                          force,
+                                          errp);
+    }
+    return ret;
+}
+
 /*
  * If offset or size are negative, respectively, they will not be included in
  * the BLOCK_IMAGE_CORRUPTED event emitted.
@@ -5802,6 +5840,7 @@ BlockDriver bdrv_qcow2 = {
     .mutable_opts        = mutable_opts,
     .bdrv_co_check       = qcow2_co_check,
     .bdrv_amend_options  = qcow2_amend_options,
+    .bdrv_co_amend       = qcow2_co_amend,
 
     .bdrv_detach_aio_context  = qcow2_detach_aio_context,
     .bdrv_attach_aio_context  = qcow2_attach_aio_context,
-- 
2.26.2