quorum: Add the rewrite-corrupted parameter to quorum

On read operations when this parameter is set and some replicas are corrupted
while quorum can be reached quorum will proceed to rewrite the correct version
of the data to fix the corrupted replicas.

This will shine with SSD where the FTL will remap the same block at another
place on rewrite.

Signed-off-by: Benoit Canet <benoit@irqsave.net>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
diff --git a/qapi/block-core.json b/qapi/block-core.json
index af6b436..de31f9f 100644
--- a/qapi/block-core.json
+++ b/qapi/block-core.json
@@ -1329,12 +1329,15 @@
 #
 # @vote-threshold: the vote limit under which a read will fail
 #
+# @rewrite-corrupted: #optional rewrite corrupted data when quorum is reached
+#                     (Since 2.1)
+#
 # Since: 2.0
 ##
 { 'type': 'BlockdevOptionsQuorum',
   'data': { '*blkverify': 'bool',
             'children': [ 'BlockdevRef' ],
-            'vote-threshold': 'int' } }
+            'vote-threshold': 'int', '*rewrite-corrupted': 'bool' } }
 
 ##
 # @BlockdevOptions