Am 20.04.2020 um 17:14 hat Eric Blake geschrieben: > On 4/20/20 8:32 AM, Kevin Wolf wrote: > > The raw format driver can simply forward the flag and let its bs->file > > child take care of actually providing the zeros. > > > > Signed-off-by: Kevin Wolf <kw...@redhat.com> > > --- > > block/raw-format.c | 3 ++- > > 1 file changed, 2 insertions(+), 1 deletion(-) > > > > diff --git a/block/raw-format.c b/block/raw-format.c > > index 3465c9a865..ab69ac46d3 100644 > > --- a/block/raw-format.c > > +++ b/block/raw-format.c > > @@ -387,7 +387,7 @@ static int coroutine_fn > > raw_co_truncate(BlockDriverState *bs, int64_t offset, > > s->size = offset; > > offset += s->offset; > > - return bdrv_co_truncate(bs->file, offset, exact, prealloc, 0, errp); > > + return bdrv_co_truncate(bs->file, offset, exact, prealloc, flags, > > errp); > > } > > static void raw_eject(BlockDriverState *bs, bool eject_flag) > > @@ -445,6 +445,7 @@ static int raw_open(BlockDriverState *bs, QDict > > *options, int flags, > > bs->supported_zero_flags = BDRV_REQ_WRITE_UNCHANGED | > > ((BDRV_REQ_FUA | BDRV_REQ_MAY_UNMAP | BDRV_REQ_NO_FALLBACK) & > > bs->file->bs->supported_zero_flags); > > + bs->supported_truncate_flags = BDRV_REQ_ZERO_WRITE; > > Shouldn't this be: > > bs->supported_truncate_flags = (bs->file->bs->supported_truncate_flags & > BDRV_REQ_ZERO_WRITE); > > rather than unconditionally advertising something that the underlying layer > may lack?
Maybe that makes more sense, yes. I think in practice it wouldn't make a difference because the nested bdrv_co_truncate() would still fail rather than silently ignoring the flag. It would behave the same as filter drivers, which also recursively call bdrv_co_truncate() without checking the flag first (which is, of course, because I don't want to modify each filter driver). Kevin