On 04/22/2013 12:33 PM, Alex Elder wrote:
On 04/22/2013 01:34 PM, Josh Durgin wrote:
Alex Elder <elder@xxxxxxxxxxx> wrote:
(This patch is available in branch "review/wip-overlap" of
the ceph-client git repository.)
A clone image has a defined overlap point with its parent image.
That is the byte offset beyond which the parent image has no
defined data to back the clone, and anything thereafter can be
viewed as being zero-filled by the clone image.
. . .
@@ -2166,6 +2166,16 @@ static int rbd_img_obj_parent_read_full(struct
rbd_obj_request *obj_request)
length = (u64)1 << rbd_dev->header.obj_order;
/*
+ * There is no defined parent data beyond the parent
+ * overlap, so limit what we read at that boundary if
+ * necessary.
+ */
+ if (img_offset + length > rbd_dev->parent_overlap) {
+ rbd_assert(img_offset < rbd_dev->parent_overlap);
+ length = obj_request->offset - obj_request->img_offset;
This doesn't look right. I think we want the length to be
rbd_dev->parent_overlap - img_offset.
You are correct. I'm glad you spotted that.
The assertion above it was right, I must have forgotten
to fix the actual assignment.
Is that the only problem you see? I can repost, but if
I agree to fix it as you describe, is that sufficient?
There's the > vs >= later too. If we agree on both, there's
no need to repost.
Josh
--
To unsubscribe from this list: send the line "unsubscribe ceph-devel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
