glusterd: Added option description, and validation function fields.

In volopt_map_entry table, added option description field, and
option validation function pointer.

Change-Id: I21c6bccd175970592b470ce3ef3f418cb99a5a43
BUG: 903478
Signed-off-by: Avra Sengupta <asengupt@redhat.com>
Reviewed-on: http://review.gluster.org/4535
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Anand Avati <avati@redhat.com>

3 files changed, 47 insertions, 29 deletions

diff --git a/xlators/mgmt/glusterd/src/glusterd-volgen.c b/xlators/mgmt/glusterd/src/glusterd-volgen.c
index d650111f04b..d154c4fd242 100644
--- a/xlators/mgmt/glusterd/src/glusterd-volgen.c
+++ b/xlators/mgmt/glusterd/src/glusterd-volgen.c
@@ -1916,33 +1916,37 @@ glusterd_get_volopt_content (dict_t * ctx, gf_boolean_t xml_out)
                 if (get_key_from_volopt (vme, &key))
                                 goto out; /*Some error while getin key*/
 
-                if (!xlator_type || strcmp (vme->voltype, xlator_type)){
-                        ret = xlator_volopt_dynload (vme->voltype,
-                                                     &dl_handle,
-                                                     &vol_opt_handle);
-                        if (ret) {
-                                dl_handle = NULL;
-                                continue;
+                if (vme->description) {
+                        descr = vme->description;
+                        def_val = vme->value;
+                } else {
+                        if (!xlator_type || strcmp (vme->voltype, xlator_type)){
+                               ret = xlator_volopt_dynload (vme->voltype,
+                                                            &dl_handle,
+                                                            &vol_opt_handle);
+                                if (ret) {
+                                        dl_handle = NULL;
+                                        continue;
+                                }
                         }
+                        ret = xlator_option_info_list (&vol_opt_handle, key,
+                                                       &def_val, &descr);
+                        if (ret) /*Swallow Error i.e if option not found*/
+                                continue;
                 }
 
-                ret = xlator_option_info_list (&vol_opt_handle, key,
-                                               &def_val, &descr);
-                if (ret) /*Swallow Error i.e if option not found*/
-                        continue;
-
                 if (xml_out) {
 #if (HAVE_LIB_XML)
                         if (xml_add_volset_element (writer,vme->key,
-                                                        def_val, descr))
+                                                    def_val, descr))
                                 goto out;
 #else
                         gf_log ("glusterd", GF_LOG_ERROR, "Libxml not present");
 #endif
                 } else {
                         snprintf (tmp_str, 2048, "Option: %s\nDefault "
-                                        "Value: %s\nDescription: %s\n\n",
-                                        vme->key, def_val, descr);
+                                  "Value: %s\nDescription: %s\n\n",
+                                  vme->key, def_val, descr);
                         strcat (output_string, tmp_str);
                 }
 
diff --git a/xlators/mgmt/glusterd/src/glusterd-volgen.h b/xlators/mgmt/glusterd/src/glusterd-volgen.h
index b495b4408bf..342183ccafc 100644
--- a/xlators/mgmt/glusterd/src/glusterd-volgen.h
+++ b/xlators/mgmt/glusterd/src/glusterd-volgen.h
@@ -86,6 +86,9 @@ typedef enum {
 
 typedef enum  { DOC, NO_DOC, GLOBAL_DOC, GLOBAL_NO_DOC } option_type_t;
 
+typedef int (*vme_option_validation) (char *key, dict_t *dict,
+                                      char **op_errstr);
+
 struct volopt_map_entry {
         char *key;
         char *voltype;
@@ -94,7 +97,10 @@ struct volopt_map_entry {
         option_type_t type;
         uint32_t flags;
         uint32_t op_version;
+        char *description;
+        vme_option_validation validate_fn;
 };
+
 int glusterd_create_rb_volfiles (glusterd_volinfo_t *volinfo,
                                  glusterd_brickinfo_t *brickinfo);
 
diff --git a/xlators/mgmt/glusterd/src/glusterd-volume-set.c b/xlators/mgmt/glusterd/src/glusterd-volume-set.c
index 41719ec8993..62e7b4259cb 100644
--- a/xlators/mgmt/glusterd/src/glusterd-volume-set.c
+++ b/xlators/mgmt/glusterd/src/glusterd-volume-set.c
@@ -41,6 +41,12 @@
  *
  * Seventh field is <op-version>.
  *
+ * Eight field is description of option: If NULL, tried to fetch from
+ * translator code's xlator_options table.
+ *
+ * Nineth field is validation function: If NULL, xlator's option specific
+ * validation will be tried, otherwise tried at glusterd code itself.
+ *
  * There are two type of entries: basic and special.
  *
  * - Basic entries are the ones where the <option> does _not_ start with
@@ -463,50 +469,52 @@ struct volopt_map_entry glusterd_volopt_map[] = {
           .voltype     = "performance/write-behind",
           .option      = "!perf",
           .value       = "on",
-          .type        = NO_DOC,
-          .op_version  = 1
+          .op_version  = 1,
+          .description = "enable/disable write-behind translator in the volume."
         },
         { .key         = "performance.read-ahead",
           .voltype     = "performance/read-ahead",
           .option      = "!perf",
           .value       = "on",
-          .type        = NO_DOC,
-          .op_version  = 1
+          .op_version  = 1,
+          .description = "enable/disable read-ahead translator in the volume."
         },
         { .key         = "performance.io-cache",
           .voltype     = "performance/io-cache",
           .option      = "!perf",
           .value       = "on",
-          .type        = NO_DOC,
-          .op_version  = 1
+          .op_version  = 1,
+          .description = "enable/disable io-cache translator in the volume."
         },
         { .key         = "performance.quick-read",
           .voltype     = "performance/quick-read",
           .option      = "!perf",
           .value       = "on",
-          .type        = NO_DOC,
-          .op_version  = 1
+          .op_version  = 1,
+          .description = "enable/disable quick-read translator in the volume."
         },
         { .key         = "performance.open-behind",
           .voltype     = "performance/open-behind",
           .option      = "!perf",
           .value       = "on",
-          .type        = NO_DOC,
-          .op_version  = 2
+          .op_version  = 2,
+          .description = "enable/disable open-behind translator in the volume."
         },
         { .key         = "performance.stat-prefetch",
           .voltype     = "performance/md-cache",
           .option      = "!perf",
           .value       = "on",
-          .type        = NO_DOC,
-          .op_version  = 1
+          .op_version  = 1,
+          .description = "enable/disable meta-data caching translator in the "
+                         "volume."
         },
         { .key         = "performance.client-io-threads",
           .voltype     = "performance/io-threads",
           .option      = "!perf",
           .value       = "off",
-          .type        = NO_DOC,
-          .op_version  = 1
+          .op_version  = 1,
+          .description = "enable/disable io-threads translator in the client "
+                         "graph of volume."
         },
         { .key         = "performance.nfs.write-behind",
           .voltype     = "performance/write-behind",