On 13.02.2017 18:22, Kevin Wolf wrote: > vvfat is the last remaining driver that can have children, but doesn't > implement .bdrv_child_perm() yet. The default handlers aren't suitable > here, so let's implement a very simple driver-specific one that protects > the internal child from being used by other users as good as our > permissions permit. > > Signed-off-by: Kevin Wolf <[email protected]> > --- > block/vvfat.c | 13 +++++++++++++ > 1 file changed, 13 insertions(+) > > diff --git a/block/vvfat.c b/block/vvfat.c > index c6bf67e..7246432 100644 > --- a/block/vvfat.c > +++ b/block/vvfat.c > @@ -3052,6 +3052,18 @@ err: > return ret; > } > > +static void vvfat_child_perm(BlockDriverState *bs, BdrvChild *c, > + const BdrvChildRole *role, > + uint64_t perm, uint64_t shared, > + uint64_t *nperm, uint64_t *nshared) > +{ > + assert(role == &child_vvfat_qcow); > + > + /* This is a private node, nobody should try to attach to it */ > + *nperm = BLK_PERM_WRITE; > + *nshared = 0;
0 for shared is probably enough to ward every other access off, but
maybe we should still pro forma request consistent read access...?
Max
> +}
> +
> static void vvfat_close(BlockDriverState *bs)
> {
> BDRVVVFATState *s = bs->opaque;
> @@ -3077,6 +3089,7 @@ static BlockDriver bdrv_vvfat = {
> .bdrv_file_open = vvfat_open,
> .bdrv_refresh_limits = vvfat_refresh_limits,
> .bdrv_close = vvfat_close,
> + .bdrv_child_perm = vvfat_child_perm,
>
> .bdrv_co_preadv = vvfat_co_preadv,
> .bdrv_co_pwritev = vvfat_co_pwritev,
>
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