mgmt/glusterd: Refactor brick graph generation in volgen.

This commit does the following:

1. Adds several new functions for generation of brick xlator units
   in a volgen. Each such function takes care of generation of only
   one xlator in volgen.

2. A new table, server_graph_table, links all individual graph generation
   functions together.  The order of xlator function generators in the
   table determines the topology of the brick graph.

3. server_graph_builder() invokes individual graph generators by walking
   through server_graph_table. Addition of debug xlators into the brick
   graph is also handled by this walk. As a result, a lot of cruft that
   is present in the exisiting implementation of this function gets
   cleaned up.

4. get_server_xlator() now makes use of server_graph_table to determine
   whether a xlator key corresponds to a server xlator or not.

Change-Id: I46bb6e331544150302eb5b33c4007917aff2586d
BUG: 1188196
Signed-off-by: Vijay Bellur <vbellur@redhat.com>
Reviewed-on: http://review.gluster.org/9751
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Krishnan Parthasarathi <kparthas@redhat.com>
Tested-by: Krishnan Parthasarathi <kparthas@redhat.com>

1 files changed, 16 insertions, 0 deletions

diff --git a/xlators/mgmt/glusterd/src/glusterd-volgen.h b/xlators/mgmt/glusterd/src/glusterd-volgen.h
index a3c093422a6..bc9c2265384 100644
--- a/xlators/mgmt/glusterd/src/glusterd-volgen.h
+++ b/xlators/mgmt/glusterd/src/glusterd-volgen.h
@@ -91,6 +91,7 @@ typedef enum {
         GF_XLATOR_MARKER,
         GF_XLATOR_IO_STATS,
         GF_XLATOR_BD,
+        GF_XLATOR_SERVER,
         GF_XLATOR_NONE,
 } glusterd_server_xlator_t;
 
@@ -125,6 +126,21 @@ struct volopt_map_entry {
         //gf_boolean_t client_option;
 };
 
+typedef
+int (*brick_xlator_builder) (volgen_graph_t *graph,
+                             glusterd_volinfo_t *volinfo, dict_t *set_dict,
+                             glusterd_brickinfo_t *brickinfo);
+
+struct volgen_brick_xlator {
+        /* function that builds a xlator */
+        brick_xlator_builder builder;
+        /* debug key for a xlator that
+         * gets used for adding debug translators like trace, error-gen
+         * before this xlator */
+        char *dbg_key;
+};
+typedef struct volgen_brick_xlator volgen_brick_xlator_t;
+
 int
 glusterd_snapdsvc_create_volfile (glusterd_volinfo_t *volinfo);