On Mon, 14 Jan 2019 at 16:47, Eric Blake <ebl...@redhat.com> wrote:
>
> We only have one caller that wants to export a bitmap name,
> which it does right after creation of the export. But there is
> still a brief window of time where an NBD client could see the
> export but not the dirty bitmap, which a robust client would
> have to interpret as meaning the entire image should be treated
> as dirty. Better is to eliminate the window entirely, by
> inlining nbd_export_bitmap() into nbd_export_new(), and refusing
> to create the bitmap in the first place if the requested bitmap
> can't be located.
> NBDExport *nbd_export_new(BlockDriverState *bs, off_t dev_offset, off_t size,
> const char *name, const char *description,
> - uint16_t nbdflags, void (*close)(NBDExport *),
> - bool writethrough, BlockBackend *on_eject_blk,
> - Error **errp)
> + const char *bitmap, uint16_t nbdflags,
> + void (*close)(NBDExport *), bool writethrough,
> + BlockBackend *on_eject_blk, Error **errp)
> {
> AioContext *ctx;
> BlockBackend *blk;
> @@ -1507,6 +1507,43 @@ NBDExport *nbd_export_new(BlockDriverState *bs, off_t
> dev_offset, off_t size,
> }
> exp->size -= exp->size % BDRV_SECTOR_SIZE;
>
> + if (bitmap) {
> + BdrvDirtyBitmap *bm = NULL;
> + BlockDriverState *bs = blk_bs(blk);
lgtm.com points out that this local variable 'bs' shadows
the 'bs' argument to the function. Is this intentional?
I think that the two can't ever be different, in which case
you could just delete the variable declaration here, but
I'm not an expert on the block layer APIs.
thanks
-- PMM
