rpc: implement server.manage-gids for group resolving on the bricks

The new volume option 'server.manage-gids' can be enabled in
environments where a user belongs to more than the current absolute
maximum of 93 groups. This option triggers the following behavior:

1. The AUTH_GLUSTERFS structure sent by GlusterFS clients (fuse, nfs or
   libgfapi) will contain only one (1) auxiliary group, instead of
   a full list. This reduces network usage and prevents problems in
   encoding the AUTH_GLUSTERFS structure which should fit in 400 bytes.
2. The single group in the RPC Calls received by the server is replaced
   by resolving the groups server-side. Permission checks and similar in
   lower xlators are applied against the full list of groups where the
   user belongs to, and not the single auxiliary group that the client
   sent.

Change-Id: I9e540de13e3022f8b63ff893ecba511129a47b91
BUG: 1053579
Signed-off-by: Niels de Vos <ndevos@redhat.com>
Reviewed-on: http://review.gluster.org/7501
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Santosh Pradhan <spradhan@redhat.com>
Reviewed-by: Harshavardhana <harsha@harshavardhana.net>
Reviewed-by: Anand Avati <avati@redhat.com>

2 files changed, 31 insertions, 0 deletions

diff --git a/xlators/protocol/client/src/client.c b/xlators/protocol/client/src/client.c
index 7726c0b8445..aecd8f8fb07 100644
--- a/xlators/protocol/client/src/client.c
+++ b/xlators/protocol/client/src/client.c
@@ -158,6 +158,8 @@ client_submit_request (xlator_t *this, void *req, call_frame_t *frame,
         struct iobref  *new_iobref = NULL;
         ssize_t         xdr_size   = 0;
         struct rpc_req  rpcreq     = {0, };
+        uint64_t        ngroups    = 0;
+        uint64_t        gid        = 0;
 
         GF_VALIDATE_OR_GOTO ("client", this, out);
         GF_VALIDATE_OR_GOTO (this->name, prog, out);
@@ -224,6 +226,18 @@ client_submit_request (xlator_t *this, void *req, call_frame_t *frame,
                 count = 1;
         }
 
+        /* do not send all groups if they are resolved server-side */
+        if (!conf->send_gids) {
+                /* copy some values for restoring later */
+                ngroups = frame->root->ngrps;
+                frame->root->ngrps = 1;
+                if (ngroups <= SMALL_GROUP_COUNT) {
+                        gid = frame->root->groups_small[0];
+                        frame->root->groups_small[0] = frame->root->gid;
+                        frame->root->groups = frame->root->groups_small;
+                }
+        }
+
         /* Send the msg */
         ret = rpc_clnt_submit (conf->rpc, prog, procnum, cbkfn, &iov, count,
                                NULL, 0, new_iobref, frame, rsphdr, rsphdr_count,
@@ -233,6 +247,13 @@ client_submit_request (xlator_t *this, void *req, call_frame_t *frame,
                 gf_log (this->name, GF_LOG_DEBUG, "rpc_clnt_submit failed");
         }
 
+        if (!conf->send_gids) {
+                /* restore previous values */
+                frame->root->ngrps = ngroups;
+                if (ngroups <= SMALL_GROUP_COUNT)
+                        frame->root->groups_small[0] = gid;
+        }
+
         ret = 0;
 
         if (new_iobref)
@@ -2314,6 +2335,8 @@ build_client_config (xlator_t *this, clnt_conf_t *conf)
         GF_OPTION_INIT ("filter-O_DIRECT", conf->filter_o_direct,
                         bool, out);
 
+        GF_OPTION_INIT ("send-gids", conf->send_gids, bool, out);
+
         ret = 0;
 out:
         return ret;
@@ -2501,6 +2524,8 @@ reconfigure (xlator_t *this, dict_t *options)
         GF_OPTION_RECONF ("filter-O_DIRECT", conf->filter_o_direct,
                           options, bool, out);
 
+        GF_OPTION_RECONF ("send-gids", conf->send_gids, options, bool, out);
+
         ret = client_init_grace_timer (this, options, conf);
         if (ret)
                 goto out;
@@ -2856,5 +2881,9 @@ struct volume_options options[] = {
           "still continue to cache the file. This works similar to NFS's "
           "behavior of O_DIRECT",
         },
+        { .key   = {"send-gids"},
+          .type  = GF_OPTION_TYPE_BOOL,
+          .default_value = "on",
+        },
         { .key   = {NULL} },
 };
diff --git a/xlators/protocol/client/src/client.h b/xlators/protocol/client/src/client.h
index bc0f5d0e9d2..7f7d511910e 100644
--- a/xlators/protocol/client/src/client.h
+++ b/xlators/protocol/client/src/client.h
@@ -125,6 +125,8 @@ typedef struct clnt_conf {
          * how manytimes set_volume is called
          */
         uint64_t               setvol_count;
+
+        gf_boolean_t           send_gids; /* let the server resolve gids */
 } clnt_conf_t;
 
 typedef struct _client_fd_ctx {