23.02.2019 3:06, John Snow wrote: > Currently, the enabled predicate means something like: > "the QAPI status of the bitmap is ACTIVE." > After this patch, it should mean exclusively: > "This bitmap is recording guest writes, and is allowed to do so." > > In many places, this is how this predicate was already used. > Internal usages of the bitmap QPI can call user_locked to find out if > the bitmap is in use by an operation. > > To accommodate this, modify the create_successor routine to now > explicitly disable the parent bitmap at creation time. > > > Justifications: > > 1. bdrv_dirty_bitmap_status suffers no change from the lack of > 1:1 parity with the new predicates because of the order in which > the predicates are checked. This is now only for compatibility. > > 2. bdrv_set_dirty() is unchanged: pre-patch, it was skipping bitmaps that were > disabled or had a successor, while post-patch it is only skipping bitmaps > that are disabled. To accommodate this, create_successor now ensures that > any bitmap with a successor is explicitly disabled. > > 3. qcow2_store_persistent_dirty_bitmaps: No functional change. This function > cares only about the literal enabled bit, and makes no effort to check if > the bitmap is in-use or not. After this patch there are still no ways to > produce an enabled bitmap with a successor. > > 4. block_dirty_bitmap_enable_prepare > block_dirty_bitmap_disable_prepare > init_dirty_bitmap_migration > nbd_export_new > > These functions care about the literal enabled bit, > and already check user_locked separately. > > Signed-off-by: John Snow<jsnow@xxxxxxxxxx> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@xxxxxxxxxxxxx> -- Best regards, Vladimir -- libvir-list mailing list libvir-list@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/libvir-list
