I don't quite understand the subject line,
what does " for just one time" mean here? From my reading of the patch
we always do it.
> +static int do_cow_at_local(struct request *req, struct sd_req *cow_hdr)
I'd call this gateway_handle_copy_on_write or similar.
> @@ -106,6 +144,14 @@ int forward_write_obj_req(struct request *req)
> memcpy(&fwd_hdr, &req->rq, sizeof(fwd_hdr));
> fwd_hdr.flags |= SD_FLAG_CMD_IO_LOCAL;
>
> + if (fwd_hdr.flags & SD_FLAG_CMD_COW) {
> + ret = do_cow_at_local(req, &fwd_hdr);
> + if (!ret) {
> + fwd_hdr.flags &= ~SD_FLAG_CMD_COW;
> + req->rq.flags &= ~SD_FLAG_CMD_COW;
> + }
> + }
If you initialize the forward hdr after the COW this code would be quite
a bit simpler.
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