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 <kw...@redhat.com>
> ---
> 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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