[PATCH] libceph: fix byte order mismatch

[PATCH] libceph: fix byte order mismatch

[Alex Elder]

A WATCH op includes an object version.  The version that's supplied
is incorrectly byte-swapped osd_req_op_watch_init() where it's first
assigned (it's been this way since that code was first added).

The result is that the version sent to the osd is wrong, because
that value gets byte-swapped again in osd_req_encode_op().  This
is the source of a sparse warning related to improper byte order in
the assignment.

The approach of using the version to avoid a race is deprecated
(see http://tracker.ceph.com/issues/3871), and the watch parameter
is no longer even examined by the osd.  So fix the assignment in
osd_req_op_watch_init() so it no longer does the byte swap.

This resolves:
    http://tracker.ceph.com/issues/3847

Signed-off-by: Alex Elder <elder@inktank.com>
---
 net/ceph/osd_client.c |    3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/net/ceph/osd_client.c b/net/ceph/osd_client.c
index 467020c..57d8db5 100644
--- a/net/ceph/osd_client.c
+++ b/net/ceph/osd_client.c
@@ -577,8 +577,7 @@ void osd_req_op_watch_init(struct ceph_osd_request
*osd_req,
 	BUG_ON(opcode != CEPH_OSD_OP_NOTIFY_ACK && opcode != CEPH_OSD_OP_WATCH);

 	op->watch.cookie = cookie;
-	/* op->watch.ver = version; */	/* XXX 3847 */
-	op->watch.ver = cpu_to_le64(version);
+	op->watch.ver = version;
 	if (opcode == CEPH_OSD_OP_WATCH && flag)
 		op->watch.flag = (u8)1;
 }
-- 
1.7.9.5

Re: [PATCH] libceph: fix byte order mismatch

[Josh Durgin]

On 04/21/2013 02:55 PM, Alex Elder wrote:
> A WATCH op includes an object version.  The version that's supplied
> is incorrectly byte-swapped osd_req_op_watch_init() where it's first
> assigned (it's been this way since that code was first added).
>
> The result is that the version sent to the osd is wrong, because
> that value gets byte-swapped again in osd_req_encode_op().  This
> is the source of a sparse warning related to improper byte order in
> the assignment.
>
> The approach of using the version to avoid a race is deprecated
> (see http://tracker.ceph.com/issues/3871), and the watch parameter
> is no longer even examined by the osd.  So fix the assignment in
> osd_req_op_watch_init() so it no longer does the byte swap.

IIRC it was never examined by the osd. Doesn't hurt to fix the encoding
though.

Reviewed-by: Josh Durgin <josh.durgin@inktank.com>

> This resolves:
>      http://tracker.ceph.com/issues/3847
>
> Signed-off-by: Alex Elder <elder@inktank.com>
> ---
>   net/ceph/osd_client.c |    3 +--
>   1 file changed, 1 insertion(+), 2 deletions(-)
>
> diff --git a/net/ceph/osd_client.c b/net/ceph/osd_client.c
> index 467020c..57d8db5 100644
> --- a/net/ceph/osd_client.c
> +++ b/net/ceph/osd_client.c
> @@ -577,8 +577,7 @@ void osd_req_op_watch_init(struct ceph_osd_request
> *osd_req,
>   	BUG_ON(opcode != CEPH_OSD_OP_NOTIFY_ACK && opcode != CEPH_OSD_OP_WATCH);
>
>   	op->watch.cookie = cookie;
> -	/* op->watch.ver = version; */	/* XXX 3847 */
> -	op->watch.ver = cpu_to_le64(version);
> +	op->watch.ver = version;
>   	if (opcode == CEPH_OSD_OP_WATCH && flag)
>   		op->watch.flag = (u8)1;
>   }
>