qcow2_can_store_new_dirty_bitmap works wrong, as it considers only bitmaps already stored in the qcow2 image and ignores persistent BdrvDirtyBitmap objects.
So, let's instead count persistent BdrvDirtyBitmaps. We load all qcow2 bitmaps on open, so there should not be any bitmap in the image for which we don't have BdrvDirtyBitmaps version. If it is - it's a kind of corruption, and no reason to check for corruptions here (open() and close() are better places for it). Signed-off-by: Vladimir Sementsov-Ogievskiy <vsement...@virtuozzo.com> --- Hi! Patch is better than discussing I thing, so here is my counter-suggestion for "[PATCH 0/5] block/dirty-bitmap: check number and size constraints against queued bitmaps" by John. It's of course needs some additional refactoring, as first assert shows bad design, I just wrote it in such manner to make minimum changes to fix the bug. Of course, Reported-by: aihua liang <ali...@redhat.com> may be applied here (if I understood correctly), and I hope that Fixes: https://bugzilla.redhat.com/show_bug.cgi?id=1712636 too. block/qcow2-bitmap.c | 38 +++++++++++++++++--------------------- 1 file changed, 17 insertions(+), 21 deletions(-) diff --git a/block/qcow2-bitmap.c b/block/qcow2-bitmap.c index b2487101ed..7d1b3eeb2b 100644 --- a/block/qcow2-bitmap.c +++ b/block/qcow2-bitmap.c @@ -1619,8 +1619,11 @@ bool qcow2_can_store_new_dirty_bitmap(BlockDriverState *bs, Error **errp) { BDRVQcow2State *s = bs->opaque; - bool found; - Qcow2BitmapList *bm_list; + BdrvDirtyBitmap *bitmap; + uint64_t bitmap_directory_size = 0; + uint32_t nb_bitmaps = 0; + + assert(!bdrv_find_dirty_bitmap(bs, name)); if (s->qcow_version < 3) { /* Without autoclear_features, we would always have to assume @@ -1636,36 +1639,29 @@ bool qcow2_can_store_new_dirty_bitmap(BlockDriverState *bs, goto fail; } - if (s->nb_bitmaps == 0) { - return true; + for (bitmap = bdrv_dirty_bitmap_next(bs, NULL); bitmap != NULL; + bitmap = bdrv_dirty_bitmap_next(bs, bitmap)) + { + if (bdrv_dirty_bitmap_get_persistence(bitmap)) { + nb_bitmaps++; + bitmap_directory_size += + calc_dir_entry_size(strlen(bdrv_dirty_bitmap_name(bitmap)), 0); + } } + nb_bitmaps++; + bitmap_directory_size += calc_dir_entry_size(strlen(name), 0); - if (s->nb_bitmaps >= QCOW2_MAX_BITMAPS) { + if (nb_bitmaps > QCOW2_MAX_BITMAPS) { error_setg(errp, "Maximum number of persistent bitmaps is already reached"); goto fail; } - if (s->bitmap_directory_size + calc_dir_entry_size(strlen(name), 0) > - QCOW2_MAX_BITMAP_DIRECTORY_SIZE) - { + if (bitmap_directory_size > QCOW2_MAX_BITMAP_DIRECTORY_SIZE) { error_setg(errp, "Not enough space in the bitmap directory"); goto fail; } - bm_list = bitmap_list_load(bs, s->bitmap_directory_offset, - s->bitmap_directory_size, errp); - if (bm_list == NULL) { - goto fail; - } - - found = find_bitmap_by_name(bm_list, name); - bitmap_list_free(bm_list); - if (found) { - error_setg(errp, "Bitmap with the same name is already stored"); - goto fail; - } - return true; fail: -- 2.18.0