[Qemu-devel] [PATCH v2] dirty-bitmap: Expose persistent flag to 'query-block'

[Qemu-devel] [PATCH v2] dirty-bitmap: Expose persistent flag to 'query-block'

[Eric Blake]

Since qemu currently doesn't flush persistent bitmaps to disk until
shutdown (which might be MUCH later), it's useful if 'query-block'
at least shows WHICH bitmaps will (eventually) make it to persistent
storage.  Update affected iotests.

Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: John Snow <jsnow@redhat.com>

---
v2: also update iotest output [John]; R-b added since changes only to tests
---
 qapi/block-core.json       |  5 ++++-
 block/dirty-bitmap.c       |  1 +
 tests/qemu-iotests/124     |  1 +
 tests/qemu-iotests/236.out | 14 ++++++++++++++
 4 files changed, 20 insertions(+), 1 deletion(-)

diff --git a/qapi/block-core.json b/qapi/block-core.json
index 5f17d67d714..f2bfe566d8d 100644
--- a/qapi/block-core.json
+++ b/qapi/block-core.json
@@ -447,11 +447,14 @@
 #
 # @status: current status of the dirty bitmap (since 2.4)
 #
+# @persistent: true if the bitmap will eventually be flushed to persistent
+#              storage (since 4.0)
+#
 # Since: 1.3
 ##
 { 'struct': 'BlockDirtyInfo',
   'data': {'*name': 'str', 'count': 'int', 'granularity': 'uint32',
-           'status': 'DirtyBitmapStatus'} }
+           'status': 'DirtyBitmapStatus', 'persistent': 'bool' } }

 ##
 # @BlockLatencyHistogramInfo:
diff --git a/block/dirty-bitmap.c b/block/dirty-bitmap.c
index 00ea36f5545..e46f72b346c 100644
--- a/block/dirty-bitmap.c
+++ b/block/dirty-bitmap.c
@@ -440,6 +440,7 @@ BlockDirtyInfoList *bdrv_query_dirty_bitmaps(BlockDriverState *bs)
         info->has_name = !!bm->name;
         info->name = g_strdup(bm->name);
         info->status = bdrv_dirty_bitmap_status(bm);
+        info->persistent = bm->persistent;
         entry->value = info;
         *plist = entry;
         plist = &entry->next;
diff --git a/tests/qemu-iotests/124 b/tests/qemu-iotests/124
index 9f189e3b540..5aa1bf1bd64 100755
--- a/tests/qemu-iotests/124
+++ b/tests/qemu-iotests/124
@@ -350,6 +350,7 @@ class TestIncrementalBackup(TestIncrementalBackupBase):
         self.assert_qmp(result, 'return[0]/dirty-bitmaps[0]/count', 458752)
         self.assert_qmp(result, 'return[0]/dirty-bitmaps[0]/granularity', 65536)
         self.assert_qmp(result, 'return[0]/dirty-bitmaps[0]/status', 'active')
+        self.assert_qmp(result, 'return[0]/dirty-bitmaps[0]/persistent', False)

         # Prepare a cluster_size=128k backup target without a backing file.
         (target, _) = bitmap0.new_target()
diff --git a/tests/qemu-iotests/236.out b/tests/qemu-iotests/236.out
index bb2d71ea5ec..5006f7bca16 100644
--- a/tests/qemu-iotests/236.out
+++ b/tests/qemu-iotests/236.out
@@ -25,12 +25,14 @@ write -P0xcd 0x3ff0000 64k
         "count": 262144,
         "granularity": 65536,
         "name": "bitmapB",
+        "persistent": false,
         "status": "active"
       },
       {
         "count": 262144,
         "granularity": 65536,
         "name": "bitmapA",
+        "persistent": false,
         "status": "active"
       }
     ]
@@ -85,12 +87,14 @@ write -P0xcd 0x3ff0000 64k
         "count": 262144,
         "granularity": 65536,
         "name": "bitmapB",
+        "persistent": false,
         "status": "active"
       },
       {
         "count": 262144,
         "granularity": 65536,
         "name": "bitmapA",
+        "persistent": false,
         "status": "active"
       }
     ]
@@ -183,18 +187,21 @@ write -P0xea 0x3fe0000 64k
         "count": 393216,
         "granularity": 65536,
         "name": "bitmapC",
+        "persistent": false,
         "status": "disabled"
       },
       {
         "count": 262144,
         "granularity": 65536,
         "name": "bitmapB",
+        "persistent": false,
         "status": "disabled"
       },
       {
         "count": 458752,
         "granularity": 65536,
         "name": "bitmapA",
+        "persistent": false,
         "status": "disabled"
       }
     ]
@@ -247,18 +254,21 @@ write -P0xea 0x3fe0000 64k
         "count": 393216,
         "granularity": 65536,
         "name": "bitmapC",
+        "persistent": false,
         "status": "disabled"
       },
       {
         "count": 262144,
         "granularity": 65536,
         "name": "bitmapB",
+        "persistent": false,
         "status": "disabled"
       },
       {
         "count": 458752,
         "granularity": 65536,
         "name": "bitmapA",
+        "persistent": false,
         "status": "disabled"
       }
     ]
@@ -304,24 +314,28 @@ write -P0xea 0x3fe0000 64k
         "count": 458752,
         "granularity": 65536,
         "name": "bitmapD",
+        "persistent": false,
         "status": "disabled"
       },
       {
         "count": 393216,
         "granularity": 65536,
         "name": "bitmapC",
+        "persistent": false,
         "status": "disabled"
       },
       {
         "count": 262144,
         "granularity": 65536,
         "name": "bitmapB",
+        "persistent": false,
         "status": "disabled"
       },
       {
         "count": 458752,
         "granularity": 65536,
         "name": "bitmapA",
+        "persistent": false,
         "status": "disabled"
       }
     ]
-- 
2.20.1

Re: [Qemu-devel] [PATCH v2] dirty-bitmap: Expose persistent flag to 'query-block'

[John Snow]

On 2/4/19 4:05 PM, Eric Blake wrote:
> Since qemu currently doesn't flush persistent bitmaps to disk until
> shutdown (which might be MUCH later), it's useful if 'query-block'
> at least shows WHICH bitmaps will (eventually) make it to persistent
> storage.  Update affected iotests.
> 
> Signed-off-by: Eric Blake <eblake@redhat.com>
> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
> Reviewed-by: John Snow <jsnow@redhat.com>

staged, thanks!