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authorFam Zheng <famz@redhat.com>2016-10-13 17:58:24 -0400
committerMax Reitz <mreitz@redhat.com>2016-10-24 17:56:07 +0200
commitfb933437de327a9a322d4c2473d0c23aa8d9a267 (patch)
tree564f091196507d82b75c498e78e8cf4ac9ed7dc2 /block/dirty-bitmap.c
parent4b62818a4f3075fce1e9335d91beef737a8fc9d3 (diff)
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block: Support meta dirty bitmap
The added group of operations enables tracking of the changed bits in the dirty bitmap. Signed-off-by: Fam Zheng <famz@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Signed-off-by: John Snow <jsnow@redhat.com> Message-id: 1476395910-8697-5-git-send-email-jsnow@redhat.com Signed-off-by: Max Reitz <mreitz@redhat.com>
Diffstat (limited to 'block/dirty-bitmap.c')
-rw-r--r--block/dirty-bitmap.c52
1 files changed, 52 insertions, 0 deletions
diff --git a/block/dirty-bitmap.c b/block/dirty-bitmap.c
index c572dfa..9c6febb 100644
--- a/block/dirty-bitmap.c
+++ b/block/dirty-bitmap.c
@@ -38,6 +38,7 @@
*/
struct BdrvDirtyBitmap {
HBitmap *bitmap; /* Dirty sector bitmap implementation */
+ HBitmap *meta; /* Meta dirty bitmap */
BdrvDirtyBitmap *successor; /* Anonymous child; implies frozen status */
char *name; /* Optional non-empty unique ID */
int64_t size; /* Size of the bitmap (Number of sectors) */
@@ -103,6 +104,56 @@ BdrvDirtyBitmap *bdrv_create_dirty_bitmap(BlockDriverState *bs,
return bitmap;
}
+/* bdrv_create_meta_dirty_bitmap
+ *
+ * Create a meta dirty bitmap that tracks the changes of bits in @bitmap. I.e.
+ * when a dirty status bit in @bitmap is changed (either from reset to set or
+ * the other way around), its respective meta dirty bitmap bit will be marked
+ * dirty as well.
+ *
+ * @bitmap: the block dirty bitmap for which to create a meta dirty bitmap.
+ * @chunk_size: how many bytes of bitmap data does each bit in the meta bitmap
+ * track.
+ */
+void bdrv_create_meta_dirty_bitmap(BdrvDirtyBitmap *bitmap,
+ int chunk_size)
+{
+ assert(!bitmap->meta);
+ bitmap->meta = hbitmap_create_meta(bitmap->bitmap,
+ chunk_size * BITS_PER_BYTE);
+}
+
+void bdrv_release_meta_dirty_bitmap(BdrvDirtyBitmap *bitmap)
+{
+ assert(bitmap->meta);
+ hbitmap_free_meta(bitmap->bitmap);
+ bitmap->meta = NULL;
+}
+
+int bdrv_dirty_bitmap_get_meta(BlockDriverState *bs,
+ BdrvDirtyBitmap *bitmap, int64_t sector,
+ int nb_sectors)
+{
+ uint64_t i;
+ int sectors_per_bit = 1 << hbitmap_granularity(bitmap->meta);
+
+ /* To optimize: we can make hbitmap to internally check the range in a
+ * coarse level, or at least do it word by word. */
+ for (i = sector; i < sector + nb_sectors; i += sectors_per_bit) {
+ if (hbitmap_get(bitmap->meta, i)) {
+ return true;
+ }
+ }
+ return false;
+}
+
+void bdrv_dirty_bitmap_reset_meta(BlockDriverState *bs,
+ BdrvDirtyBitmap *bitmap, int64_t sector,
+ int nb_sectors)
+{
+ hbitmap_reset(bitmap->meta, sector, nb_sectors);
+}
+
bool bdrv_dirty_bitmap_frozen(BdrvDirtyBitmap *bitmap)
{
return bitmap->successor;
@@ -233,6 +284,7 @@ static void bdrv_do_release_matching_dirty_bitmap(BlockDriverState *bs,
if ((!bitmap || bm == bitmap) && (!only_named || bm->name)) {
assert(!bm->active_iterators);
assert(!bdrv_dirty_bitmap_frozen(bm));
+ assert(!bm->meta);
QLIST_REMOVE(bm, list);
hbitmap_free(bm->bitmap);
g_free(bm->name);