[Qemu-devel] [PATCH 3/4] qcow2: add a migration blocker

[Anthony Liguori <aliguori@us.ibm.com>]

Now when you try to migrate with qcow2, you get:

(qemu) migrate tcp:localhost:1025
Block format 'qcow2' used by device 'ide0-hd0' does not support feature 'live migration'
(qemu)

Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
---
 block/qcow2.c |    9 +++++++++
 block/qcow2.h |    2 ++
 qemu-tool.c   |    9 +++++++++
 qerror.c      |    4 ++++
 qerror.h      |    3 +++
 5 files changed, 27 insertions(+), 0 deletions(-)

diff --git a/block/qcow2.c b/block/qcow2.c
index ef057d3..500cbbf 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -29,6 +29,7 @@
 #include "block/qcow2.h"
 #include "qemu-error.h"
 #include "qerror.h"
+#include "migration.h"
 
 /*
   Differences with QCOW:
@@ -277,6 +278,11 @@ static int qcow2_open(BlockDriverState *bs, int flags)
         goto fail;
     }
 
+    error_set(&s->migration_blocker,
+              QERR_BLOCK_FORMAT_FEATURE_NOT_SUPPORTED,
+              "qcow2", bs->device_name, "live migration");
+    migrate_add_blocker(s->migration_blocker);
+
     /* Initialise locks */
     qemu_co_mutex_init(&s->lock);
 
@@ -621,6 +627,9 @@ static void qcow2_close(BlockDriverState *bs)
     BDRVQcowState *s = bs->opaque;
     g_free(s->l1_table);
 
+    migrate_del_blocker(s->migration_blocker);
+    error_free(s->migration_blocker);
+
     qcow2_cache_flush(bs, s->l2_table_cache);
     qcow2_cache_flush(bs, s->refcount_block_cache);
 
diff --git a/block/qcow2.h b/block/qcow2.h
index 531af39..0734b23 100644
--- a/block/qcow2.h
+++ b/block/qcow2.h
@@ -125,6 +125,8 @@ typedef struct BDRVQcowState {
     int snapshots_size;
     int nb_snapshots;
     QCowSnapshot *snapshots;
+
+    Error *migration_blocker;
 } BDRVQcowState;
 
 /* XXX: use std qcow open function ? */
diff --git a/qemu-tool.c b/qemu-tool.c
index e9f7fe1..5df7279 100644
--- a/qemu-tool.c
+++ b/qemu-tool.c
@@ -15,6 +15,7 @@
 #include "monitor.h"
 #include "qemu-timer.h"
 #include "qemu-log.h"
+#include "migration.h"
 
 #include <sys/time.h>
 
@@ -92,3 +93,11 @@ int64_t qemu_get_clock_ns(QEMUClock *clock)
 {
     return 0;
 }
+
+void migrate_add_blocker(Error *reason)
+{
+}
+
+void migrate_del_blocker(Error *reason)
+{
+}
diff --git a/qerror.c b/qerror.c
index 8e30e2d..fdf62b9 100644
--- a/qerror.c
+++ b/qerror.c
@@ -49,6 +49,10 @@ static const QErrorStringTable qerror_table[] = {
         .desc      = "Device '%(device)' can't go on a %(bad_bus_type) bus",
     },
     {
+        .error_fmt = QERR_BLOCK_FORMAT_FEATURE_NOT_SUPPORTED,
+        .desc      = "Block format '%(format)' used by device '%(name)' does not support feature '%(feature)'",
+    },
+    {
         .error_fmt = QERR_BUS_NOT_FOUND,
         .desc      = "Bus '%(bus)' not found",
     },
diff --git a/qerror.h b/qerror.h
index 7e2eebf..2d3d43b 100644
--- a/qerror.h
+++ b/qerror.h
@@ -54,6 +54,9 @@ QError *qobject_to_qerror(const QObject *obj);
 #define QERR_BAD_BUS_FOR_DEVICE \
     "{ 'class': 'BadBusForDevice', 'data': { 'device': %s, 'bad_bus_type': %s } }"
 
+#define QERR_BLOCK_FORMAT_FEATURE_NOT_SUPPORTED \
+    "{ 'class': 'BlockFormatFeatureNotSupported', 'data': { 'format': %s, 'name': %s, 'feature': %s } }"
+
 #define QERR_BUS_NOT_FOUND \
     "{ 'class': 'BusNotFound', 'data': { 'bus': %s } }"
 
-- 
1.7.4.1