drive and blockdev backup cannot use readonly bitmaps, because the
sync=incremental mechanism actually edits the bitmaps on success.

If you really want to do this operation, use a copied bitmap.

Signed-off-by: John Snow <jsnow@redhat.com>
---
 blockdev.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/blockdev.c b/blockdev.c
index 5d74479ba7..c8255dda0b 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -3526,7 +3526,7 @@ static BlockJob *do_drive_backup(DriveBackup *backup, JobTxn *txn,
             bdrv_unref(target_bs);
             goto out;
         }
-        if (bdrv_dirty_bitmap_check(bmap, BDRV_BITMAP_ALLOW_RO, errp)) {
+        if (bdrv_dirty_bitmap_check(bmap, BDRV_BITMAP_DEFAULT, errp)) {
             goto out;
         }
     }
@@ -3636,7 +3636,7 @@ BlockJob *do_blockdev_backup(BlockdevBackup *backup, JobTxn *txn,
             error_setg(errp, "Bitmap '%s' could not be found", backup->bitmap);
             goto out;
         }
-        if (bdrv_dirty_bitmap_check(bmap, BDRV_BITMAP_ALLOW_RO, errp)) {
+        if (bdrv_dirty_bitmap_check(bmap, BDRV_BITMAP_DEFAULT, errp)) {
             goto out;
         }
     }
-- 
2.17.2

On 3/1/19 1:15 PM, John Snow wrote:
> drive and blockdev backup cannot use readonly bitmaps, because the
> sync=incremental mechanism actually edits the bitmaps on success.
> 
> If you really want to do this operation, use a copied bitmap.

In fact, that's what I ended up doing in my libvirt patches, always
running sync=incremental on a temporary copy.

Reviewed-by: Eric Blake <eblake@redhat.com>

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3226
Virtualization:  qemu.org | libvirt.org

01.03.2019 22:15, John Snow wrote:
> drive and blockdev backup cannot use readonly bitmaps, because the
> sync=incremental mechanism actually edits the bitmaps on success.
> 
> If you really want to do this operation, use a copied bitmap.
> 
> Signed-off-by: John Snow <jsnow@redhat.com>


Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>


> ---
>   blockdev.c | 4 ++--
>   1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/blockdev.c b/blockdev.c
> index 5d74479ba7..c8255dda0b 100644
> --- a/blockdev.c
> +++ b/blockdev.c
> @@ -3526,7 +3526,7 @@ static BlockJob *do_drive_backup(DriveBackup *backup, JobTxn *txn,
>               bdrv_unref(target_bs);
>               goto out;
>           }
> -        if (bdrv_dirty_bitmap_check(bmap, BDRV_BITMAP_ALLOW_RO, errp)) {
> +        if (bdrv_dirty_bitmap_check(bmap, BDRV_BITMAP_DEFAULT, errp)) {
>               goto out;
>           }
>       }
> @@ -3636,7 +3636,7 @@ BlockJob *do_blockdev_backup(BlockdevBackup *backup, JobTxn *txn,
>               error_setg(errp, "Bitmap '%s' could not be found", backup->bitmap);
>               goto out;
>           }
> -        if (bdrv_dirty_bitmap_check(bmap, BDRV_BITMAP_ALLOW_RO, errp)) {
> +        if (bdrv_dirty_bitmap_check(bmap, BDRV_BITMAP_DEFAULT, errp)) {
>               goto out;
>           }
>       }
> 


-- 
Best regards,
Vladimir