Re: [Qemu-block] [RFC PATCH 17/41] block: Request real permissions in blk_new_open()

[Max Reitz]

On 13.02.2017 18:22, Kevin Wolf wrote:
> We can figure out the necessary permissions from the flags that the
> caller passed.
> 
> Signed-off-by: Kevin Wolf <address@hidden>
> ---
>  block/block-backend.c | 16 ++++++++++++++--
>  1 file changed, 14 insertions(+), 2 deletions(-)
> 
> diff --git a/block/block-backend.c b/block/block-backend.c
> index 1f80854..e10a278 100644
> --- a/block/block-backend.c
> +++ b/block/block-backend.c
> @@ -160,6 +160,7 @@ BlockBackend *blk_new_open(const char *filename, const 
> char *reference,
>  {
>      BlockBackend *blk;
>      BlockDriverState *bs;
> +    uint64_t perm;
>  
>      blk = blk_new(0, BLK_PERM_ALL);

What about this?

Max

>      bs = bdrv_open(filename, reference, options, flags, errp);
> @@ -168,9 +169,20 @@ BlockBackend *blk_new_open(const char *filename, const 
> char *reference,
>          return NULL;
>      }
>  
> -    /* FIXME Use real permissions */
> +    /* blk_new_open() is mainly used in .bdrv_create implementations and the
> +     * tools where sharing isn't a concern because the BDS stays private, so 
> we
> +     * just request permission according to the flags.
> +     *
> +     * The exceptions are xen_disk and blockdev_init(); in these cases, the
> +     * caller of blk_new_open() doesn't make use of the permissions, but they
> +     * shouldn't hurt either. We can still share everything here because the
> +     * guest devices will add their own blockers if they can't share. */
> +    perm = BLK_PERM_CONSISTENT_READ;
> +    if (flags & BDRV_O_RDWR) {
> +        perm |= BLK_PERM_WRITE;
> +    }
>      blk->root = bdrv_root_attach_child(bs, "root", &child_root,
> -                                       0, BLK_PERM_ALL, blk, &error_abort);
> +                                       perm, BLK_PERM_ALL, blk, 
> &error_abort);
>  
>      return blk;
>  }
>

signature.asc
Description: OpenPGP digital signature