[Qemu-devel] [PATCH 14/22] qcow2: delete bitmaps on truncate

[Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>]

This will not touch loaded bitmaps, as they are alredy removed from the
image.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
---
 block/qcow2-bitmap.c | 38 ++++++++++++++++++++++++++++++++++++++
 block/qcow2.c        |  9 ++++++---
 block/qcow2.h        |  2 ++
 3 files changed, 46 insertions(+), 3 deletions(-)

diff --git a/block/qcow2-bitmap.c b/block/qcow2-bitmap.c
index 1c3abea..2642afe 100644
--- a/block/qcow2-bitmap.c
+++ b/block/qcow2-bitmap.c
@@ -624,6 +624,44 @@ out:
     return ret;
 }
 
+
+int qcow2_delete_bitmaps(BlockDriverState *bs)
+{
+    int ret;
+    BDRVQcow2State *s = bs->opaque;
+    uint8_t *dir;
+    uint64_t dir_size;
+    Qcow2BitmapDirEntry *e;
+
+    if (s->nb_bitmaps == 0) {
+        /* No bitmaps - nothing to do */
+        return 0;
+    }
+
+    dir_size = s->bitmap_directory_size;
+    dir = directory_read(bs, s->bitmap_directory_offset,
+                         s->bitmap_directory_size, NULL);
+    if (dir == NULL) {
+        ret = -EINVAL;
+        goto out;
+    }
+
+    ret = directory_update(bs, NULL, 0, 0);
+    if (ret < 0) {
+        goto out;
+    }
+
+    /* to be consistent, free bitmap only after successfull directory update */
+    for_each_bitmap_dir_entry(e, dir, dir_size) {
+        free_bitmap_clusters(bs, e);
+    }
+
+out:
+    g_free(dir);
+
+    return ret;
+}
+
 /* store_bitmap_data()
  * Store bitmap to image, filling bitamp table accordingly.
  */
diff --git a/block/qcow2.c b/block/qcow2.c
index 8238205..aa967ed 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -2592,9 +2592,12 @@ static int qcow2_truncate(BlockDriverState *bs, int64_t offset)
 
     /* cannot proceed if image has bitmaps */
     if (s->nb_bitmaps) {
-        /* FIXME */
-        error_report("Can't resize an image which has bitmaps");
-        return -ENOTSUP;
+        /* FIXME: not loaded bitmaps will be lost */
+        ret = qcow2_delete_bitmaps(bs);
+        if (ret < 0) {
+            error_report("Can't remove bitmaps from qcow2 on truncate");
+            return ret;
+        }
     }
 
     /* shrinking is currently not supported */
diff --git a/block/qcow2.h b/block/qcow2.h
index dfcf4c6..af18efc 100644
--- a/block/qcow2.h
+++ b/block/qcow2.h
@@ -606,6 +606,8 @@ int qcow2_read_snapshots(BlockDriverState *bs);
 /* qcow2-bitmap.c functions */
 int qcow2_read_bitmaps(BlockDriverState *bs, Error **errp);
 
+int qcow2_delete_bitmaps(BlockDriverState *bs);
+
 /* qcow2-cache.c functions */
 Qcow2Cache *qcow2_cache_create(BlockDriverState *bs, int num_tables);
 int qcow2_cache_destroy(BlockDriverState* bs, Qcow2Cache *c);
-- 
1.8.3.1