[v13,03/17] qmp: Add block-dirty-bitmap-add and block-dirty-bitmap-remove

diff --git a/block.c b/block.c
index 6e08b26..60dbdbd 100644
--- a/block.c
+++ b/block.c
@@ -5461,6 +5461,26 @@  int bdrv_get_dirty(BlockDriverState *bs, BdrvDirtyBitmap *bitmap, int64_t sector
     }
 }
 
+/**
+ * Chooses a default granularity based on the existing cluster size,
+ * but clamped between [4K, 64K]. Defaults to 64K in the case that there
+ * is no cluster size information available.
+ */
+uint32_t bdrv_get_default_bitmap_granularity(BlockDriverState *bs)
+{
+    BlockDriverInfo bdi;
+    uint32_t granularity;
+
+    if (bdrv_get_info(bs, &bdi) >= 0 && bdi.cluster_size > 0) {
+        granularity = MAX(4096, bdi.cluster_size);
+        granularity = MIN(65536, granularity);
+    } else {
+        granularity = 65536;
+    }
+
+    return granularity;
+}
+
 void bdrv_dirty_iter_init(BlockDriverState *bs,
                           BdrvDirtyBitmap *bitmap, HBitmapIter *hbi)
 {
diff --git a/block/mirror.c b/block/mirror.c
index f8aac33..1cb700e 100644
--- a/block/mirror.c
+++ b/block/mirror.c
@@ -668,15 +668,7 @@  static void mirror_start_job(BlockDriverState *bs, BlockDriverState *target,
     MirrorBlockJob *s;
 
     if (granularity == 0) {
-        /* Choose the default granularity based on the target file's cluster
-         * size, clamped between 4k and 64k.  */
-        BlockDriverInfo bdi;
-        if (bdrv_get_info(target, &bdi) >= 0 && bdi.cluster_size != 0) {
-            granularity = MAX(4096, bdi.cluster_size);
-            granularity = MIN(65536, granularity);
-        } else {
-            granularity = 65536;
-        }
+        granularity = bdrv_get_default_bitmap_granularity(target);
     }
 
     assert ((granularity & (granularity - 1)) == 0);
diff --git a/blockdev.c b/blockdev.c
index 7d34960..8842e39 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -1173,6 +1173,48 @@  out_aio_context:
     return NULL;
 }
 
+/**
+ * Return a dirty bitmap (if present), after validating
+ * the node reference and bitmap names. Returns NULL on error,
+ * including when the BDS and/or bitmap is not found.
+ */
+static BdrvDirtyBitmap *block_dirty_bitmap_lookup(const char *node,
+                                                  const char *name,
+                                                  BlockDriverState **pbs,
+                                                  Error **errp)
+{
+    BlockDriverState *bs;
+    BdrvDirtyBitmap *bitmap;
+
+    if (!node) {
+        error_setg(errp, "Node cannot be NULL");
+        return NULL;
+    }
+    if (!name) {
+        error_setg(errp, "Bitmap name cannot be NULL");
+        return NULL;
+    }
+
+    bs = bdrv_lookup_bs(node, node, NULL);
+    if (!bs) {
+        error_setg(errp, "Node '%s' not found", node);
+        return NULL;
+    }
+
+    /* If caller provided a BDS*, provide the result of that lookup, too. */
+    if (pbs) {
+        *pbs = bs;
+    }
+
+    bitmap = bdrv_find_dirty_bitmap(bs, name);
+    if (!bitmap) {
+        error_setg(errp, "Dirty bitmap '%s' not found", name);
+        return NULL;
+    }
+
+    return bitmap;
+}
+
 /* New and old BlockDriverState structs for atomic group operations */
 
 typedef struct BlkTransactionState BlkTransactionState;
@@ -1953,6 +1995,64 @@  void qmp_block_set_io_throttle(const char *device, int64_t bps, int64_t bps_rd,
     aio_context_release(aio_context);
 }
 
+void qmp_block_dirty_bitmap_add(const char *node, const char *name,
+                                bool has_granularity, uint32_t granularity,
+                                Error **errp)
+{
+    AioContext *aio_context;
+    BlockDriverState *bs;
+
+    if (!name || name[0] == '\0') {
+        error_setg(errp, "Bitmap name cannot be empty");
+        return;
+    }
+
+    bs = bdrv_lookup_bs(node, node, errp);
+    if (!bs) {
+        return;
+    }
+
+    aio_context = bdrv_get_aio_context(bs);
+    aio_context_acquire(aio_context);
+
+    if (has_granularity) {
+        if (granularity < 512 || !is_power_of_2(granularity)) {
+            error_setg(errp, "Granularity must be power of 2 "
+                             "and at least 512");
+            goto out;
+        }
+    } else {
+        /* Default to cluster size, if available: */
+        granularity = bdrv_get_default_bitmap_granularity(bs);
+    }
+
+    bdrv_create_dirty_bitmap(bs, granularity, name, errp);
+
+ out:
+    aio_context_release(aio_context);
+}
+
+void qmp_block_dirty_bitmap_remove(const char *node, const char *name,
+                                   Error **errp)
+{
+    AioContext *aio_context;
+    BlockDriverState *bs;
+    BdrvDirtyBitmap *bitmap;
+
+    bitmap = block_dirty_bitmap_lookup(node, name, &bs, errp);
+    if (!bitmap || !bs) {
+        return;
+    }
+
+    aio_context = bdrv_get_aio_context(bs);
+    aio_context_acquire(aio_context);
+
+    bdrv_dirty_bitmap_make_anon(bs, bitmap);
+    bdrv_release_dirty_bitmap(bs, 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 abdf8d6..3589132 100644
--- a/include/block/block.h
+++ b/include/block/block.h
@@ -447,6 +447,7 @@  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);
 BlockDirtyInfoList *bdrv_query_dirty_bitmaps(BlockDriverState *bs);
+uint32_t bdrv_get_default_bitmap_granularity(BlockDriverState *bs);
 int bdrv_get_dirty(BlockDriverState *bs, BdrvDirtyBitmap *bitmap, int64_t sector);
 void bdrv_set_dirty_bitmap(BlockDriverState *bs, BdrvDirtyBitmap *bitmap,
                            int64_t cur_sector, int nr_sectors);
diff --git a/qapi/block-core.json b/qapi/block-core.json
index 39291e7..764719d 100644
--- a/qapi/block-core.json
+++ b/qapi/block-core.json
@@ -959,6 +959,61 @@ 
             '*on-target-error': 'BlockdevOnError' } }
 
 ##
+# @BlockDirtyBitmap
+#
+# @node: name of device/node which the bitmap is tracking
+#
+# @name: name of the dirty bitmap
+#
+# Since 2.3
+##
+{ 'type': 'BlockDirtyBitmap',
+  'data': { 'node': 'str', 'name': 'str' } }
+
+##
+# @BlockDirtyBitmapAdd
+#
+# @node: name of device/node which the bitmap is tracking
+#
+# @name: name of the dirty bitmap
+#
+# @granularity: #optional the bitmap granularity, default is 64k for
+#               block-dirty-bitmap-add
+#
+# Since 2.3
+##
+{ 'type': 'BlockDirtyBitmapAdd',
+  'data': { 'node': 'str', 'name': 'str', '*granularity': 'uint32' } }
+
+##
+# @block-dirty-bitmap-add
+#
+# Create a dirty bitmap with a name on the node
+#
+# Returns: nothing on success
+#          If @node is not a valid block device or node, DeviceNotFound
+#          If @name is already taken, GenericError with an explanation
+#
+# Since 2.3
+##
+{ 'command': 'block-dirty-bitmap-add',
+  'data': 'BlockDirtyBitmapAdd' }
+
+##
+# @block-dirty-bitmap-remove
+#
+# Remove a dirty bitmap on the node
+#
+# Returns: nothing on success
+#          If @node is not a valid block device or node, DeviceNotFound
+#          If @name is not found, GenericError with an explanation
+#
+# Since 2.3
+##
+{ 'command': 'block-dirty-bitmap-remove',
+  '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 a85d847..881a810 100644
--- a/qmp-commands.hx
+++ b/qmp-commands.hx
@@ -1244,6 +1244,57 @@  Example:
 EQMP
 
     {
+        .name       = "block-dirty-bitmap-add",
+        .args_type  = "node:B,name:s,granularity:i?",
+        .mhandler.cmd_new = qmp_marshal_input_block_dirty_bitmap_add,
+    },
+    {
+        .name       = "block-dirty-bitmap-remove",
+        .args_type  = "node:B,name:s",
+        .mhandler.cmd_new = qmp_marshal_input_block_dirty_bitmap_remove,
+    },
+
+SQMP
+
+block-dirty-bitmap-add
+----------------------
+Since 2.3
+
+Create a dirty bitmap with a name on the device, and start tracking the writes.
+
+Arguments:
+
+- "node": device/node on which to create dirty bitmap (json-string)
+- "name": name of the new dirty bitmap (json-string)
+- "granularity": granularity to track writes with (int, optional)
+
+Example:
+
+-> { "execute": "block-dirty-bitmap-add", "arguments": { "node": "drive0",
+                                                   "name": "bitmap0" } }
+<- { "return": {} }
+
+block-dirty-bitmap-remove
+-------------------------
+Since 2.3
+
+Stop write tracking and remove the dirty bitmap that was created with
+block-dirty-bitmap-add.
+
+Arguments:
+
+- "node": device/node on which to remove dirty bitmap (json-string)
+- "name": name of the dirty bitmap to remove (json-string)
+
+Example:
+
+-> { "execute": "block-dirty-bitmap-remove", "arguments": { "node": "drive0",
+                                                      "name": "bitmap0" } }
+<- { "return": {} }
+
+EQMP
+
+    {
         .name       = "blockdev-snapshot-sync",
         .args_type  = "device:s?,node-name:s?,snapshot-file:s,snapshot-node-name:s?,format:s?,mode:s?",
         .mhandler.cmd_new = qmp_marshal_input_blockdev_snapshot_sync,