On 6/3/19 8:00 AM, Vladimir Sementsov-Ogievskiy wrote:
> Add functionality to make bitmap temporary anonymous. It will be used
> to implement bitmap remove transaction action. We need hide bitmap
> persistence too, as there are should not be unnamed persistent bitmaps.
>
Ah, so this effectively ... "hides" a bitmap from any further
transaction actions. It also "hides" it from getting flushed to disk...
sort of?
The outer loop in store works with bdrv_dirty_bitmap_next, and we'll
skip this bitmap because it's anonymous/not persistent.
There's a second loop where we iterate bm_list, and we'll skip storing
this bitmap because that entry won't have an in-memory bitmap associated
with it in bm_list.
...But then we'll call update_ext_header_and_dir with the stale entries
in bm_list?
> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsement...@virtuozzo.com>
> ---
> include/block/dirty-bitmap.h | 2 ++
> block/dirty-bitmap.c | 26 ++++++++++++++++++++++++++
> 2 files changed, 28 insertions(+)
>
> diff --git a/include/block/dirty-bitmap.h b/include/block/dirty-bitmap.h
> index 8044ace63e..542e437123 100644
> --- a/include/block/dirty-bitmap.h
> +++ b/include/block/dirty-bitmap.h
> @@ -116,5 +116,7 @@ bool bdrv_dirty_bitmap_next_dirty_area(BdrvDirtyBitmap
> *bitmap,
> BdrvDirtyBitmap *bdrv_reclaim_dirty_bitmap_locked(BlockDriverState *bs,
> BdrvDirtyBitmap *bitmap,
> Error **errp);
> +void bdrv_dirty_bitmap_hide(BdrvDirtyBitmap *bitmap);
> +void bdrv_dirty_bitmap_unhide(BdrvDirtyBitmap *bitmap);
>
> #endif
> diff --git a/block/dirty-bitmap.c b/block/dirty-bitmap.c
> index 49646a30e6..592964635e 100644
> --- a/block/dirty-bitmap.c
> +++ b/block/dirty-bitmap.c
> @@ -35,6 +35,10 @@ struct BdrvDirtyBitmap {
> bool busy; /* Bitmap is busy, it can't be used via QMP
> */
> BdrvDirtyBitmap *successor; /* Anonymous child, if any. */
> char *name; /* Optional non-empty unique ID */
> + char *hidden_name; /* Backup of @name for removal transaction
> + action. Used for hide/unhide API. */
> + bool hidden_persistent; /* Backup of @persistent for removal
> transaction
> + action. */
> int64_t size; /* Size of the bitmap, in bytes */
> bool disabled; /* Bitmap is disabled. It ignores all writes
> to
> the device */
> @@ -849,3 +853,25 @@ out:
> qemu_mutex_unlock(src->mutex);
> }
> }
> +
> +void bdrv_dirty_bitmap_hide(BdrvDirtyBitmap *bitmap)
> +{
> + qemu_mutex_lock(bitmap->mutex);
> + assert(!bitmap->hidden_name);
> + bitmap->hidden_name = bitmap->name;
> + bitmap->hidden_persistent = bitmap->persistent;
> + bitmap->name = NULL;
> + bitmap->persistent = false;
> + qemu_mutex_unlock(bitmap->mutex);
> +}
> +
> +void bdrv_dirty_bitmap_unhide(BdrvDirtyBitmap *bitmap)
> +{
> + qemu_mutex_lock(bitmap->mutex);
> + assert(!bitmap->name);
> + bitmap->name = bitmap->hidden_name;
> + bitmap->persistent = bitmap->hidden_persistent;
> + bitmap->hidden_name = NULL;
> + bitmap->hidden_persistent = false;
> + qemu_mutex_unlock(bitmap->mutex);
> +}
>
