Re: osd_req_encode_op() breakage?

From: Alex Elder
Date: Wed Apr 18 2012 - 11:09:06 EST

I got dropped off the lists for a bit and didn't see
this at first. I don't know whether Sage responded to you or
not. I'm getting back to you, just to be sure.

> Date: Sat, 14 Apr 2012 03:34:20 +0100
> From: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
> To: Sage Weil <sage@xxxxxxxxxxxx>
> Cc: linux-kernel@xxxxxxxxxxxxxxx, linux-fsdevel@xxxxxxxxxxxxxxx
> Subject: osd_req_encode_op() breakage?
> static void osd_req_encode_op(struct ceph_osd_request *req,
> struct ceph_osd_op *dst,
> struct ceph_osd_req_op *src)
> {
> dst->op = cpu_to_le16(src->op);
> switch (dst->op) {
> is an interesting thing to say, seeing that CEPH_OSD_OP_READ are
> all host-endian... Should that be "switch (src->op)" instead?

Yes, you are absolutely correct.

We have obviously not done endianness checks in this code for
some time.

I will commit a fix and credit you for it. I'll also make sure
we are doing proper testing for this sort of thing on a regular


> AFAICS, that sucker had appeared in that form back in
> commit 68b4476b0bc13fef18266b4140309a30e86739d2
> Author: Yehuda Sadeh <yehuda@xxxxxxxxxxxxxxx>
> Date: Tue Apr 6 15:01:27 2010 -0700
> ceph: messenger and osdc changes for rbd
> and it seems to be broken on big-endian hosts. Doesn't look like a misspelled
> le16_to_cpu() either, since dst->op ends up going on the wire...
> I'm really mystified by that - it looks like it must've shown up immediately
> on big-endian hosts; it's not like it was an obscure codepath, after all...
> Comments?
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