glusterd/geo-rep: slave volume uuid to identify a geo-rep session

Problem:
Currently, it is possible to create multiple geo-rep session from
the Master host to Slave host(s), where Slave host(s) belonging
to the same volume.

For example:
Consider Master Host M1 having volume tv1 and Slave volume tv2,
which spans across two Slave hosts S1 and S2.
Currently, it is possible to create geo-rep session from
M1(tv1) to S1(tv2) as well as from M1(tv1) to S2(tv2).

When the Slave Host is alone modified, it is identified as a new geo-rep
session (as slave host and slave volume together are identifying
Slave side).

Also, it is possible to create both root and non-root geo-rep session between
same Master volume and Slave volume. This should also be avoided.

Solution:
This multiple geo-rep session creation must be avoided and
in order to avoid, use Slave volume uuid to identify a Slave.
This way, we can identify whether a session is already created for
the same Slave volume and avoid creating again (using different host).

When the session creation is forced in the above scenario, rename
the existing geo-rep session directory with new Slave Host mentioned.

Change-Id: I9239759cbc0d15dad63c48b8cf62950bb687c7c8
BUG: 1294813
Signed-off-by: Saravanakumar Arumugam <sarumuga@redhat.com>
Signed-off-by: Aravinda VK <avishwan@redhat.com>
Reviewed-on: http://review.gluster.org/13111
Reviewed-by: Kotresh HR <khiremat@redhat.com>
Tested-by: Kotresh HR <khiremat@redhat.com>
Smoke: Gluster Build System <jenkins@build.gluster.com>
NetBSD-regression: NetBSD Build System <jenkins@build.gluster.org>
Reviewed-by: Atin Mukherjee <amukherj@redhat.com>
CentOS-regression: Gluster Build System <jenkins@build.gluster.com>

1 files changed, 9 insertions, 0 deletions

diff --git a/xlators/mgmt/glusterd/src/glusterd-geo-rep.h b/xlators/mgmt/glusterd/src/glusterd-geo-rep.h
index 5568b5cf316..0524ec48fca 100644
--- a/xlators/mgmt/glusterd/src/glusterd-geo-rep.h
+++ b/xlators/mgmt/glusterd/src/glusterd-geo-rep.h
@@ -14,6 +14,15 @@
 #define GSYNC_CONF_TEMPLATE GEOREP"/gsyncd_template.conf"
 #endif
 
+/* <slave host>::<slave volume> */
+#define SLAVE_URL_INFO_MAX (_POSIX_HOST_NAME_MAX + GD_VOLUME_NAME_MAX + 3)
+
+/* slave info format:
+ * <master host uuid>:ssh://{<slave_user>@}<slave host>::<slave volume> \
+ * :<slave volume uuid> */
+#define VOLINFO_SLAVE_URL_MAX (_POSIX_LOGIN_NAME_MAX + (2*GF_UUID_BUF_SIZE) \
+                                 + SLAVE_URL_INFO_MAX + 10)
+
 typedef struct glusterd_gsync_status_temp {
         dict_t *rsp_dict;
         glusterd_volinfo_t *volinfo;