libceph: mon_get_version request infrastructure

Add support for mon_get_version requests to libceph.  This reuses much
of the ceph_mon_generic_request infrastructure, with one exception.
Older OSDs don't set mon_get_version reply hdr->tid even if the
original request had a non-zero tid, which makes it impossible to
lookup ceph_mon_generic_request contexts by tid in get_generic_reply()
for such replies.  As a workaround, we allocate a reply message on the
reply path.  This can probably interfere with revoke, but I don't see
a better way.

Signed-off-by: Ilya Dryomov <ilya.dryomov@inktank.com>
Reviewed-by: Sage Weil <sage@inktank.com>

1 files changed, 6 insertions, 3 deletions

diff --git a/include/linux/ceph/mon_client.h b/include/linux/ceph/mon_client.h
index a486f390dfbe..585ef9450e9d 100644
--- a/include/linux/ceph/mon_client.h
+++ b/include/linux/ceph/mon_client.h
@@ -40,9 +40,9 @@ struct ceph_mon_request {
 };
 
 /*
- * ceph_mon_generic_request is being used for the statfs and poolop requests
- * which are bening done a bit differently because we need to get data back
- * to the caller
+ * ceph_mon_generic_request is being used for the statfs, poolop and
+ * mon_get_version requests which are being done a bit differently
+ * because we need to get data back to the caller
  */
 struct ceph_mon_generic_request {
         struct kref kref;
@@ -108,6 +108,9 @@ extern void ceph_monc_request_next_osdmap(struct ceph_mon_client *monc);
 extern int ceph_monc_do_statfs(struct ceph_mon_client *monc,
                                struct ceph_statfs *buf);
 
+extern int ceph_monc_do_get_version(struct ceph_mon_client *monc,
+                                    const char *what, u64 *newest);
+
 extern int ceph_monc_open_session(struct ceph_mon_client *monc);
 
 extern int ceph_monc_validate_auth(struct ceph_mon_client *monc);