glusterd / cli: mount-broker service

Mountbroker is configured in glusterd volfile through a DSL
which is restriced enough to be able to appear in the role
of the value of a volfile knob.

Basically the DSL describes set-theorical requirements
against the option set which is sent by the cli (in the
hope of getting a mount with these options).

If the requirements meet and the volume id and the uid
who is to "own" the mount can be unambigously deduced from
the given request, glusterd does the mount with the given
parameters.

The use case of geo-replication is sugared by means of volume
options which then generate a complete mount-broker option set.

Demo:

- add the following option to your glusterd volfile:

    option mountbroker-root /tmp/mbr
    option mountbroker.fool EQL(volfile-id=pop*|user-map-root=*|volfile-server=localhost)&MEET(user-map-root=john|user-map-root=jane)

- before starting glusterd, create /tmp/mbr owned by root with mode 0755

- with cli, do

   $ gluster system:: mount fool volfile-id=pop33 user-map-root=jane volfile-server=localhost

- on succesful completion (volume pop33 exists and is started, jane is a valid username),
  the mount path will be echoed to you

- you can get rid of the mount by

   $ gluster system:: umount <mount-path>

Change-Id: I629cf64add0a45500d05becc3316f67cdb5b42ff
BUG: 3482
Reviewed-on: http://review.gluster.com/128
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Vijay Bellur <vijay@gluster.com>

1 files changed, 21 insertions, 0 deletions

diff --git a/rpc/xdr/src/cli1-xdr.x b/rpc/xdr/src/cli1-xdr.x
index 70d221cbb3b..9fc9f02d29d 100644
--- a/rpc/xdr/src/cli1-xdr.x
+++ b/rpc/xdr/src/cli1-xdr.x
@@ -411,3 +411,24 @@ struct gf1_cli_status_volume_rsp {
        string op_errstr<>;
        opaque dict<>;
 };
+
+struct gf1_cli_mount_req {
+        string label<>;
+        opaque dict<>;
+};
+
+struct gf1_cli_mount_rsp {
+       int op_ret;
+       int op_errno;
+       string path<>;
+};
+
+struct gf1_cli_umount_req {
+        int lazy;
+        string path<>;
+};
+
+struct gf1_cli_mount_rsp {
+       int op_ret;
+       int op_errno;
+};