Re: [PATCH] rbd: don't treat CEPH_OSD_OP_DELETE as extent op

[Alex Elder <elder@ieee.org>]

On 11/24/2014 03:59 AM, Ilya Dryomov wrote:
> CEPH_OSD_OP_DELETE is not an extent op, stop treating it as such.  This
> sneaked in with discard patches - it's one of the three osd ops (the
> other two are CEPH_OSD_OP_TRUNCATE and CEPH_OSD_OP_ZERO) that discard
> is implemented with.
> 
> Signed-off-by: Ilya Dryomov <idryomov@redhat.com>

Is the CEPH_OSD_OP_DELETE used in ceph_zero_partial_object()
an extent op?  If it is not, you should get rid of the BUG_ON()
in osd_req_op_extent_init() that allows CEPH_OSD_OP_DELETE.

And if that's the case it looks like that function or
ceph_osdc_new_request() handle CEPH_OSD_OP_DELETE
properly--so it's not treated as an extent op.

And:  osd_req_encode_op() encodes a CEPH_OSD_OP_DELETE
as an extent op as well.

If it *can* be an extent op (but just not as used by RBD)
then it warrants a comment here that explains why it is
not being initialized as an extent op.

					-Alex

> ---
>  drivers/block/rbd.c | 8 ++++++--
>  1 file changed, 6 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
> index 27b71a0b72d0..1df0802bf6cb 100644
> --- a/drivers/block/rbd.c
> +++ b/drivers/block/rbd.c
> @@ -2370,8 +2370,12 @@ static void rbd_img_obj_request_fill(struct rbd_obj_request *obj_request,
>  		opcode = CEPH_OSD_OP_READ;
>  	}
>  
> -	osd_req_op_extent_init(osd_request, num_ops, opcode, offset, length,
> -				0, 0);
> +	if (opcode == CEPH_OSD_OP_DELETE)
> +		osd_req_op_init(osd_request, num_ops, opcode);
> +	else
> +		osd_req_op_extent_init(osd_request, num_ops, opcode,
> +				       offset, length, 0, 0);
> +
>  	if (obj_request->type == OBJ_REQUEST_BIO)
>  		osd_req_op_extent_osd_data_bio(osd_request, num_ops,
>  					obj_request->bio_list, length);
>