[Qemu-devel] [PATCH] qmp: add query-block-dirty-bitmap

[Vladimir Sementsov-Ogievskiy]

Add qmp command to query dirty bitmap. This is needed for external
backup.

Signed-off-by: Vladimir Sementsov-Ogievskiy <address@hidden>
---
 block.c               | 41 ++++++++++++++++++++++++++++++++++++++++
 blockdev.c            | 21 +++++++++++++++++++++
 include/block/block.h |  2 ++
 qapi/block-core.json  | 52 +++++++++++++++++++++++++++++++++++++++++++++++++++
 qmp-commands.hx       | 22 ++++++++++++++++++++++
 5 files changed, 138 insertions(+)

diff --git a/block.c b/block.c
index 5709d3d..9a28589 100644
--- a/block.c
+++ b/block.c
@@ -3717,6 +3717,47 @@ void bdrv_set_dirty(BlockDriverState *bs, int64_t 
cur_sector,
     }
 }
 
+BlockDirtyBitmapInfo *bdrv_query_dirty_bitmap(BlockDriverState *bs,
+                                              BdrvDirtyBitmap *bitmap)
+{
+    BlockDirtyBitmapInfo *info = g_new0(BlockDirtyBitmapInfo, 1);
+    BlockDirtyRegionList **plist = &info->dirty_regions;
+    uint64_t begin = 0, end = 0, size = bitmap->size;
+    HBitmap *hb = bitmap->bitmap;
+
+    info->dirty_count = bdrv_get_dirty_count(bitmap);
+    info->granularity = bdrv_dirty_bitmap_granularity(bitmap);
+    info->size = bitmap->size;
+    info->name = g_strdup(bitmap->name);
+    info->disabled = bitmap->disabled;
+    info->dirty_regions = NULL;
+
+    for (; begin < size; ++begin) {
+        BlockDirtyRegion *region;
+        BlockDirtyRegionList *entry;
+
+        if (!hbitmap_get(hb, begin)) {
+            continue;
+        }
+
+        for (end = begin + 1; end < size && hbitmap_get(hb, end); ++end) {
+            ;
+        }
+
+        region = g_new0(BlockDirtyRegion, 1);
+        entry = g_new0(BlockDirtyRegionList, 1);
+        region->start = begin;
+        region->count = end - begin;
+        entry->value = region;
+        *plist = entry;
+        plist = &entry->next;
+
+        begin = end;
+    }
+
+    return info;
+}
+
 /**
  * Advance an HBitmapIter to an arbitrary offset.
  */
diff --git a/blockdev.c b/blockdev.c
index 07cfe25..d2bc453 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -2734,6 +2734,27 @@ void qmp_block_dirty_bitmap_clear(const char *node, 
const char *name,
     aio_context_release(aio_context);
 }
 
+BlockDirtyBitmapInfo *qmp_query_block_dirty_bitmap(const char *node,
+                                                   const char *name,
+                                                   Error **errp)
+{
+    AioContext *aio_context;
+    BdrvDirtyBitmap *bitmap;
+    BlockDriverState *bs;
+    BlockDirtyBitmapInfo *ret = NULL;
+
+    bitmap = block_dirty_bitmap_lookup(node, name, &bs, &aio_context, errp);
+    if (!bitmap) {
+        return NULL;
+    }
+
+    ret = bdrv_query_dirty_bitmap(bs, bitmap);
+
+    aio_context_release(aio_context);
+
+    return ret;
+}
+
 void hmp_drive_del(Monitor *mon, const QDict *qdict)
 {
     const char *id = qdict_get_str(qdict, "id");
diff --git a/include/block/block.h b/include/block/block.h
index 25f36dc..9d6bd33 100644
--- a/include/block/block.h
+++ b/include/block/block.h
@@ -505,6 +505,8 @@ void bdrv_set_dirty_bitmap(BdrvDirtyBitmap *bitmap,
                            int64_t cur_sector, int nr_sectors);
 void bdrv_reset_dirty_bitmap(BdrvDirtyBitmap *bitmap,
                              int64_t cur_sector, int nr_sectors);
+BlockDirtyBitmapInfo *bdrv_query_dirty_bitmap(BlockDriverState *bs,
+                                              BdrvDirtyBitmap *bitmap);
 void bdrv_dirty_iter_init(BdrvDirtyBitmap *bitmap, struct HBitmapIter *hbi);
 void bdrv_set_dirty_iter(struct HBitmapIter *hbi, int64_t offset);
 int64_t bdrv_get_dirty_count(BdrvDirtyBitmap *bitmap);
diff --git a/qapi/block-core.json b/qapi/block-core.json
index 0a915ed..12ed759 100644
--- a/qapi/block-core.json
+++ b/qapi/block-core.json
@@ -414,6 +414,58 @@
 ##
 { 'command': 'query-block', 'returns': ['BlockInfo'] }
 
+##
+# @BlockDirtyRegion:
+#
+# Region in bytes.
+#
+# @start: first byte
+#
+# @count: number of bytes in the region
+#
+# Since: 2.3
+##
+{ 'struct': 'BlockDirtyRegion',
+  'data': { 'start': 'int', 'count': 'int' } }
+
+##
+# @BlockDirtyBitmapInfo
+#
+# @name: the name of the dirty bitmap
+#
+# @size: size of the dirty bitmap in sectors
+#
+# @granularity: granularity of the dirty bitmap in bytes
+#
+# @disabled: whether the dirty bitmap is disabled
+#
+# @dirty-count: number of dirty bytes according to the dirty bitmap
+#
+# @dirty-regions: dirty regions of the bitmap
+#
+# Since 2.3
+##
+{ 'struct': 'BlockDirtyBitmapInfo',
+  'data': { 'name': 'str',
+            'size': 'int',
+            'granularity': 'int',
+            'disabled': 'bool',
+            'dirty-count': 'int',
+            'dirty-regions': ['BlockDirtyRegion'] } }
+
+##
+# @query-block-dirty-bitmap
+#
+# Get a description for specified dirty bitmap including it's dirty regions.
+# This command is in general for testing purposes.
+#
+# Returns: @BlockDirtyBitmapInfo
+#
+# Since: 2.3
+##
+{ 'command': 'query-block-dirty-bitmap',
+  'data': 'BlockDirtyBitmap',
+  'returns': 'BlockDirtyBitmapInfo' }
 
 ##
 # @BlockDeviceTimedStats:
diff --git a/qmp-commands.hx b/qmp-commands.hx
index db072a6..75d9345 100644
--- a/qmp-commands.hx
+++ b/qmp-commands.hx
@@ -1457,6 +1457,28 @@ Example:
 EQMP
 
     {
+        .name       = "query-block-dirty-bitmap",
+        .args_type  = "node:B,name:s",
+        .mhandler.cmd_new = qmp_marshal_query_block_dirty_bitmap,
+    },
+
+SQMP
+
+query-block-dirty-bitmap
+------------------------
+Since 2.6
+
+Get dirty bitmap info, including contents. Bitmap data are returned as array of
+dirty regions
+
+Arguments:
+
+- "node": device/node on which to remove dirty bitmap (json-string)
+- "name": name of the dirty bitmap to remove (json-string)
+
+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_blockdev_snapshot_sync,
-- 
1.8.3.1