[Qemu-devel] [PATCH v10 09/13] qmp: Add block-dirty-bitmap-enable and block-dirty-bitmap-disable

[John Snow <jsnow@redhat.com>]

From: Fam Zheng <famz@redhat.com>

This allows to put the dirty bitmap into a disabled state where 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>
Signed-off-by: John Snow <jsnow@redhat.com>
---
 block.c               | 19 ++++++++++++++++++-
 blockdev.c            | 40 ++++++++++++++++++++++++++++++++++++++++
 include/block/block.h |  2 ++
 qapi/block-core.json  | 28 ++++++++++++++++++++++++++++
 qmp-commands.hx       | 10 ++++++++++
 5 files changed, 98 insertions(+), 1 deletion(-)

diff --git a/block.c b/block.c
index 990b9eb..166a04f 100644
--- a/block.c
+++ b/block.c
@@ -57,6 +57,7 @@ struct BdrvDirtyBitmap {
     int64_t size;
     int64_t granularity;
     char *name;
+    bool enabled;
     QLIST_ENTRY(BdrvDirtyBitmap) list;
 };
 
@@ -5401,6 +5402,7 @@ BdrvDirtyBitmap *bdrv_create_dirty_bitmap(BlockDriverState *bs,
     bitmap->granularity = granularity;
     bitmap->bitmap = hbitmap_alloc(bitmap->size, ffs(sector_granularity) - 1);
     bitmap->name = g_strdup(name);
+    bitmap->enabled = true;
     QLIST_INSERT_HEAD(&bs->dirty_bitmaps, bitmap, list);
     return bitmap;
 }
@@ -5419,6 +5421,16 @@ void bdrv_release_dirty_bitmap(BlockDriverState *bs, BdrvDirtyBitmap *bitmap)
     }
 }
 
+void bdrv_disable_dirty_bitmap(BdrvDirtyBitmap *bitmap)
+{
+    bitmap->enabled = false;
+}
+
+void bdrv_enable_dirty_bitmap(BdrvDirtyBitmap *bitmap)
+{
+    bitmap->enabled = true;
+}
+
 BlockDirtyInfoList *bdrv_query_dirty_bitmaps(BlockDriverState *bs)
 {
     BdrvDirtyBitmap *bm;
@@ -5486,7 +5498,9 @@ void bdrv_dirty_iter_init(BlockDriverState *bs,
 void bdrv_set_dirty_bitmap(BlockDriverState *bs, BdrvDirtyBitmap *bitmap,
                            int64_t cur_sector, int nr_sectors)
 {
-    hbitmap_set(bitmap->bitmap, cur_sector, nr_sectors);
+    if (bitmap->enabled) {
+        hbitmap_set(bitmap->bitmap, cur_sector, nr_sectors);
+    }
 }
 
 void bdrv_reset_dirty_bitmap(BlockDriverState *bs, BdrvDirtyBitmap *bitmap,
@@ -5509,6 +5523,9 @@ static 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 95251c7..118cb6c 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -1994,6 +1994,46 @@ void qmp_block_dirty_bitmap_remove(const char *node_ref, const char *name,
     aio_context_release(aio_context);
 }
 
+void qmp_block_dirty_bitmap_enable(const char *node_ref, const char *name,
+                                   Error **errp)
+{
+    AioContext *aio_context;
+    BdrvDirtyBitmap *bitmap;
+    BlockDriverState *bs;
+
+    bitmap = block_dirty_bitmap_lookup(node_ref, name, &bs, errp);
+    if (!bitmap) {
+        return;
+    }
+
+    aio_context = bdrv_get_aio_context(bs);
+    aio_context_acquire(aio_context);
+
+    bdrv_enable_dirty_bitmap(bitmap);
+
+    aio_context_release(aio_context);
+}
+
+void qmp_block_dirty_bitmap_disable(const char *node_ref, const char *name,
+                                    Error **errp)
+{
+    AioContext *aio_context;
+    BdrvDirtyBitmap *bitmap;
+    BlockDriverState *bs;
+
+    bitmap = block_dirty_bitmap_lookup(node_ref, name, &bs, errp);
+    if (!bitmap) {
+        return;
+    }
+
+    aio_context = bdrv_get_aio_context(bs);
+    aio_context_acquire(aio_context);
+
+    bdrv_disable_dirty_bitmap(bitmap);
+
+    aio_context_release(aio_context);
+}
+
 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 e51ca45..8b18f7c 100644
--- a/include/block/block.h
+++ b/include/block/block.h
@@ -442,6 +442,8 @@ BdrvDirtyBitmap *bdrv_copy_dirty_bitmap(BlockDriverState *bs,
 BdrvDirtyBitmap *bdrv_reclaim_dirty_bitmap(BlockDriverState *bs,
                                            BdrvDirtyBitmap *failed);
 void bdrv_release_dirty_bitmap(BlockDriverState *bs, BdrvDirtyBitmap *bitmap);
+void bdrv_disable_dirty_bitmap(BdrvDirtyBitmap *bitmap);
+void bdrv_enable_dirty_bitmap(BdrvDirtyBitmap *bitmap);
 BlockDirtyInfoList *bdrv_query_dirty_bitmaps(BlockDriverState *bs);
 uint64_t bdrv_get_default_bitmap_granularity(BlockDriverState *bs);
 uint64_t bdrv_dirty_bitmap_granularity(BlockDriverState *bs,
diff --git a/qapi/block-core.json b/qapi/block-core.json
index f79d165..3e863b9 100644
--- a/qapi/block-core.json
+++ b/qapi/block-core.json
@@ -949,6 +949,34 @@
   'data': 'BlockDirtyBitmap' }
 
 ##
+# @block-dirty-bitmap-enable
+#
+# Enable a dirty bitmap on the device
+#
+# Returns: nothing on success
+#          If @node-ref is not a valid block device, DeviceNotFound
+#          If @name is not found, GenericError with an explaining message
+#
+# Since 2.3
+##
+{'command': 'block-dirty-bitmap-enable',
+  'data': 'BlockDirtyBitmap' }
+
+##
+# @block-dirty-bitmap-disable
+#
+# Disable a dirty bitmap on the device
+#
+# Returns: nothing on success
+#          If @node-ref is not a valid block device, DeviceNotFound
+#          If @name is not found, GenericError with an explaining message
+#
+# Since 2.3
+##
+{'command': 'block-dirty-bitmap-disable',
+  'data': 'BlockDirtyBitmap' }
+
+##
 # @block_set_io_throttle:
 #
 # Change I/O throttle limits for a block drive.
diff --git a/qmp-commands.hx b/qmp-commands.hx
index 4ffca8a..59be8eb 100644
--- a/qmp-commands.hx
+++ b/qmp-commands.hx
@@ -1211,6 +1211,16 @@ EQMP
         .args_type  = "node-ref:B,name:s",
         .mhandler.cmd_new = qmp_marshal_input_block_dirty_bitmap_remove,
     },
+    {
+        .name       = "block-dirty-bitmap-enable",
+        .args_type  = "node-ref:B,name:s",
+        .mhandler.cmd_new = qmp_marshal_input_block_dirty_bitmap_enable,
+    },
+    {
+        .name       = "block-dirty-bitmap-disable",
+        .args_type  = "node-ref:B,name:s",
+        .mhandler.cmd_new = qmp_marshal_input_block_dirty_bitmap_disable,
+    },
 
 SQMP
 
-- 
1.9.3