On Fri, Aug 9, 2019 at 9:05 AM Dongsheng Yang
<dongsheng.yang@xxxxxxxxxxxx> wrote:
>
> Response will be an encoded string, which includes a length.
> So we need to allocate more buf of sizeof (__le32) in reply
> buffer, and pass the reply buffer size as a parameter in
> rbd_obj_method_sync function.
>
> Signed-off-by: Dongsheng Yang <dongsheng.yang@xxxxxxxxxxxx>
> ---
> drivers/block/rbd.c | 9 ++++++---
> 1 file changed, 6 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
> index 3327192..db55ece 100644
> --- a/drivers/block/rbd.c
> +++ b/drivers/block/rbd.c
> @@ -5661,14 +5661,17 @@ static int rbd_dev_v2_object_prefix(struct rbd_device *rbd_dev)
> void *reply_buf;
> int ret;
> void *p;
> + size_t size;
>
> - reply_buf = kzalloc(RBD_OBJ_PREFIX_LEN_MAX, GFP_KERNEL);
> + /* Response will be an encoded string, which includes a length */
> + size = sizeof (__le32) + RBD_OBJ_PREFIX_LEN_MAX;
> + reply_buf = kzalloc(size, GFP_KERNEL);
> if (!reply_buf)
> return -ENOMEM;
>
> ret = rbd_obj_method_sync(rbd_dev, &rbd_dev->header_oid,
> &rbd_dev->header_oloc, "get_object_prefix",
> - NULL, 0, reply_buf, RBD_OBJ_PREFIX_LEN_MAX);
> + NULL, 0, reply_buf, size);
> dout("%s: rbd_obj_method_sync returned %d\n", __func__, ret);
> if (ret < 0)
> goto out;
> @@ -6697,7 +6700,7 @@ static int rbd_dev_image_id(struct rbd_device *rbd_dev)
>
> ret = rbd_obj_method_sync(rbd_dev, &oid, &rbd_dev->header_oloc,
> "get_id", NULL, 0,
> - response, RBD_IMAGE_ID_LEN_MAX);
> + response, size);
> dout("%s: rbd_obj_method_sync returned %d\n", __func__, ret);
> if (ret == -ENOENT) {
> image_id = kstrdup("", GFP_KERNEL);
Hi Dongsheng,
AFAIR RBD_OBJ_PREFIX_LEN_MAX and RBD_IMAGE_ID_LEN_MAX are arbitrary
constants with enough slack for length, etc. We shouldn't ever see
object prefixes or image ids that are longer than 62 bytes.
Thanks,
Ilya
