[Qemu-devel] [PATCH 8/9] qmp: Add dirty-bitmap-disable command

[Fam Zheng <famz@redhat.com>]

This will put the dirty bitmap into a disabled state and no more
writes will be tracked.

It will be used before backup or writing to persistent file.

Signed-off-by: Fam Zheng <famz@redhat.com>
---
 block.c               | 15 +++++++++++++++
 blockdev.c            | 22 ++++++++++++++++++++++
 include/block/block.h |  2 ++
 qapi-schema.json      | 16 ++++++++++++++++
 qmp-commands.hx       |  5 +++++
 5 files changed, 60 insertions(+)

diff --git a/block.c b/block.c
index 0e59a9a..62efb93 100644
--- a/block.c
+++ b/block.c
@@ -53,6 +53,7 @@ struct BdrvDirtyBitmap {
     HBitmap *bitmap;
     int refcnt;
     char name[1024];
+    bool enabled;
     QLIST_ENTRY(BdrvDirtyBitmap) list;
 };
 
@@ -4580,6 +4581,7 @@ BdrvDirtyBitmap *bdrv_create_dirty_bitmap(BlockDriverState *bs,
     if (name) {
         pstrcpy(bitmap->name, sizeof(bitmap->name), name);
     }
+    bitmap->enabled = true;
     QLIST_INSERT_HEAD(&bs->dirty_bitmaps, bitmap, list);
     return bitmap;
 }
@@ -4606,6 +4608,16 @@ void bdrv_reference_dirty_bitmap(BlockDriverState *bs, BdrvDirtyBitmap *bitmap)
     bitmap->refcnt++;
 }
 
+void bdrv_disable_dirty_bitmap(BlockDriverState *bs, BdrvDirtyBitmap *bitmap)
+{
+    bitmap->enabled = false;
+}
+
+void bdrv_enable_dirty_bitmap(BlockDriverState *bs, BdrvDirtyBitmap *bitmap)
+{
+    bitmap->enabled = true;
+}
+
 BlockDirtyInfoList *bdrv_query_dirty_bitmaps(BlockDriverState *bs)
 {
     BdrvDirtyBitmap *bm;
@@ -4654,6 +4666,9 @@ void bdrv_set_dirty(BlockDriverState *bs, int64_t cur_sector,
 {
     BdrvDirtyBitmap *bitmap;
     QLIST_FOREACH(bitmap, &bs->dirty_bitmaps, list) {
+        if (!bitmap->enabled) {
+            continue;
+        }
         hbitmap_set(bitmap->bitmap, cur_sector, nr_sectors);
     }
 }
diff --git a/blockdev.c b/blockdev.c
index ac00562..090a681 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -1694,6 +1694,28 @@ void qmp_dirty_bitmap_remove(const char *device, const char *name,
     bdrv_release_dirty_bitmap(bs, bitmap);
 }
 
+void qmp_dirty_bitmap_disable(const char *device, const char *name,
+                              bool has_granularity, int64_t granularity,
+                              Error **errp)
+{
+    BlockDriverState *bs;
+    BdrvDirtyBitmap *bitmap;
+
+    bs = bdrv_find(device);
+    if (!bs) {
+        error_set(errp, QERR_DEVICE_NOT_FOUND, device);
+        return;
+    }
+
+    bitmap = bdrv_find_dirty_bitmap(bs, name);
+    if (!bitmap) {
+        error_setg(errp, "Dirty bitmap not found: %s", name);
+        return;
+    }
+
+    bdrv_disable_dirty_bitmap(bs, bitmap);
+}
+
 int do_drive_del(Monitor *mon, const QDict *qdict, QObject **ret_data)
 {
     const char *id = qdict_get_str(qdict, "id");
diff --git a/include/block/block.h b/include/block/block.h
index 858baad..8b9b142 100644
--- a/include/block/block.h
+++ b/include/block/block.h
@@ -433,6 +433,8 @@ BdrvDirtyBitmap *bdrv_find_dirty_bitmap(BlockDriverState *bs,
 void bdrv_dirty_bitmap_make_anon(BlockDriverState *bs, BdrvDirtyBitmap *bitmap);
 void bdrv_release_dirty_bitmap(BlockDriverState *bs, BdrvDirtyBitmap *bitmap);
 void bdrv_reference_dirty_bitmap(BlockDriverState *bs, BdrvDirtyBitmap *bitmap);
+void bdrv_disable_dirty_bitmap(BlockDriverState *bs, BdrvDirtyBitmap *bitmap);
+void bdrv_enable_dirty_bitmap(BlockDriverState *bs, BdrvDirtyBitmap *bitmap);
 BlockDirtyInfoList *bdrv_query_dirty_bitmaps(BlockDriverState *bs);
 int bdrv_dirty_bitmap_granularity(BlockDriverState *bs,
                                   BdrvDirtyBitmap *bitmap);
diff --git a/qapi-schema.json b/qapi-schema.json
index eef894c..8a81026 100644
--- a/qapi-schema.json
+++ b/qapi-schema.json
@@ -2109,6 +2109,22 @@
   'data': { 'device': 'str', 'name': 'str' } }
 
 ##
+# @dirty-bitmap-disable
+#
+# Disable a dirty bitmap on the device
+#
+# Setting granularity has no effect here.
+#
+# Returns: nothing on success
+#          If @device is not a valid block device, DeviceNotFound
+#          If @name is not found, GenericError with an explaining message
+#
+# Since 2.0
+##
+{'command': 'dirty-bitmap-disable',
+  'data': 'DirtyBitmap' }
+
+##
 # @migrate_cancel
 #
 # Cancel the current executing migration process.
diff --git a/qmp-commands.hx b/qmp-commands.hx
index eaae70e..88b5f58 100644
--- a/qmp-commands.hx
+++ b/qmp-commands.hx
@@ -1074,6 +1074,11 @@ EQMP
         .args_type  = "device:B,name:s",
         .mhandler.cmd_new = qmp_marshal_input_dirty_bitmap_remove,
     },
+    {
+        .name       = "dirty-bitmap-disable",
+        .args_type  = "device:B,name:s",
+        .mhandler.cmd_new = qmp_marshal_input_dirty_bitmap_disable,
+    },
 
 SQMP
 
-- 
1.8.5.2