[Qemu-devel] [PATCH v4 08/20] block: Add bitmap disabled status

[John Snow <jsnow@redhat.com>]

Add a status indicating the enabled/disabled state of the bitmap.
A bitmap is by default enabled, but you can lock the bitmap into
a read-only state by setting disabled = true.

A previous version of this patch added a QMP interface for changing
the state of the bitmap, but it has since been removed for now until
a use case emerges where this state must be revealed to the user.

The disabled state WILL be used internally for bitmap migration and
bitmap persistence.

Signed-off-by: Fam Zheng <famz@redhat.com>
Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
---
 block.c               | 25 +++++++++++++++++++++++++
 include/block/block.h |  3 +++
 2 files changed, 28 insertions(+)

diff --git a/block.c b/block.c
index 2a590aa..0bf5565 100644
--- a/block.c
+++ b/block.c
@@ -54,6 +54,7 @@
 struct BdrvDirtyBitmap {
     HBitmap *bitmap;
     char *name;
+    bool disabled;
     QLIST_ENTRY(BdrvDirtyBitmap) list;
 };
 
@@ -5448,10 +5449,16 @@ BdrvDirtyBitmap *bdrv_create_dirty_bitmap(BlockDriverState *bs,
     bitmap = g_new0(BdrvDirtyBitmap, 1);
     bitmap->bitmap = hbitmap_alloc(bitmap_size, ffs(sector_granularity) - 1);
     bitmap->name = g_strdup(name);
+    bitmap->disabled = false;
     QLIST_INSERT_HEAD(&bs->dirty_bitmaps, bitmap, list);
     return bitmap;
 }
 
+bool bdrv_dirty_bitmap_enabled(BdrvDirtyBitmap *bitmap)
+{
+    return !bitmap->disabled;
+}
+
 void bdrv_release_dirty_bitmap(BlockDriverState *bs, BdrvDirtyBitmap *bitmap)
 {
     BdrvDirtyBitmap *bm, *next;
@@ -5466,6 +5473,16 @@ void bdrv_release_dirty_bitmap(BlockDriverState *bs, BdrvDirtyBitmap *bitmap)
     }
 }
 
+void bdrv_disable_dirty_bitmap(BdrvDirtyBitmap *bitmap)
+{
+    bitmap->disabled = true;
+}
+
+void bdrv_enable_dirty_bitmap(BdrvDirtyBitmap *bitmap)
+{
+    bitmap->disabled = false;
+}
+
 BlockDirtyInfoList *bdrv_query_dirty_bitmaps(BlockDriverState *bs)
 {
     BdrvDirtyBitmap *bm;
@@ -5530,12 +5547,14 @@ void bdrv_dirty_iter_init(BlockDriverState *bs,
 void bdrv_set_dirty_bitmap(BlockDriverState *bs, BdrvDirtyBitmap *bitmap,
                            int64_t cur_sector, int nr_sectors)
 {
+    assert(bdrv_dirty_bitmap_enabled(bitmap));
     hbitmap_set(bitmap->bitmap, cur_sector, nr_sectors);
 }
 
 void bdrv_reset_dirty_bitmap(BlockDriverState *bs, BdrvDirtyBitmap *bitmap,
                              int64_t cur_sector, int nr_sectors)
 {
+    assert(bdrv_dirty_bitmap_enabled(bitmap));
     hbitmap_reset(bitmap->bitmap, cur_sector, nr_sectors);
 }
 
@@ -5544,6 +5563,9 @@ static void bdrv_set_dirty(BlockDriverState *bs, int64_t cur_sector,
 {
     BdrvDirtyBitmap *bitmap;
     QLIST_FOREACH(bitmap, &bs->dirty_bitmaps, list) {
+        if (!bdrv_dirty_bitmap_enabled(bitmap)) {
+            continue;
+        }
         hbitmap_set(bitmap->bitmap, cur_sector, nr_sectors);
     }
 }
@@ -5553,6 +5575,9 @@ static void bdrv_reset_dirty(BlockDriverState *bs, int64_t cur_sector,
 {
     BdrvDirtyBitmap *bitmap;
     QLIST_FOREACH(bitmap, &bs->dirty_bitmaps, list) {
+        if (!bdrv_dirty_bitmap_enabled(bitmap)) {
+            continue;
+        }
         hbitmap_reset(bitmap->bitmap, cur_sector, nr_sectors);
     }
 }
diff --git a/include/block/block.h b/include/block/block.h
index 493b7c5..029a8a7 100644
--- a/include/block/block.h
+++ b/include/block/block.h
@@ -457,9 +457,12 @@ BdrvDirtyBitmap *bdrv_find_dirty_bitmap(BlockDriverState *bs,
                                         const char *name);
 void bdrv_dirty_bitmap_make_anon(BlockDriverState *bs, BdrvDirtyBitmap *bitmap);
 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);
 uint32_t bdrv_get_default_bitmap_granularity(BlockDriverState *bs);
 uint32_t bdrv_dirty_bitmap_granularity(BdrvDirtyBitmap *bitmap);
+bool bdrv_dirty_bitmap_enabled(BdrvDirtyBitmap *bitmap);
 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);
-- 
2.1.0