On Mon, Apr 16, 2018 at 06:58:46PM +0200, Max Reitz wrote: > Update the rest of the filter drivers to support > BDRV_REQ_WRITE_UNCHANGED. They already forward write request flags to > their children, so we just have to announce support for it. > > This patch does not cover the replication driver because that currently > does not support flags at all, and because it just grabs the WRITE > permission for its children when it can, so we should be fine just > submitting the incoming WRITE_UNCHANGED requests as normal writes. > > It also does not cover format drivers for similar reasons. They all use > bdrv_format_default_perms() as their .bdrv_child_perm() implementation > so they just always grab the WRITE permission for their file children > whenever possible. In addition, it often would be difficult to > ascertain whether incoming unchanging writes end up as unchanging writes > in their files. So we just leave them as normal potentially changing > writes. > > Signed-off-by: Max Reitz <mre...@redhat.com> > --- > block/blkdebug.c | 9 +++++---- > block/blkreplay.c | 3 +++ > block/blkverify.c | 3 +++ > block/cor.c | 10 ++++++---- > block/mirror.c | 2 ++ > block/raw-format.c | 9 +++++---- > block/throttle.c | 6 ++++-- > 7 files changed, 28 insertions(+), 14 deletions(-)
Reviewed-by: Stefan Hajnoczi <stefa...@redhat.com>
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