classification: provide infra to start labelling features/components

`doc/xlator-classification.md` talks about the reasoning and expectations

Reviewers are expected to check the 'category' of new
option / translator added in the codebase, and make sure the flag
is always properly set. It helps to keep the 'expectation' proper
on the codebase.

updates: #430
Change-Id: I2bfc9934a5f6eed77fcc3e20364046242decc82c
Signed-off-by: Amar Tumballi <amarts@redhat.com>

4 files changed, 45 insertions, 4 deletions

diff --git a/libglusterfs/src/glusterfs.h b/libglusterfs/src/glusterfs.h
index 423804300a..31fb65b866 100644
--- a/libglusterfs/src/glusterfs.h
+++ b/libglusterfs/src/glusterfs.h
@@ -390,6 +390,35 @@ typedef enum {
         GF_FOP_PRI_MAX,                 /* Highest */
 } gf_fop_pri_t;
 
+typedef enum {
+        /* The 'component' (xlator / option) is not yet setting the flag */
+        GF_UNCLASSIFIED = 0,
+        /* The 'component' is experimental, should not be recommened
+           in production mode */
+        GF_EXPERIMENTAL,
+        /* The 'component' is tech preview, ie, it is 'mostly' working as
+           expected, but can have some of the corner cases, which is not
+           handled. */
+        GF_TECH_PREVIEW,
+        /* The 'component' is good to run. Has good enough test and
+           documentation coverage. */
+        GF_MAINTAINED,
+        /* The component is:
+           - no more a focus
+           - no more solving a valid use case
+           - no more maintained, no volunteers to maintain
+           - there is 'maintained' or 'tech-preview' feature,
+           which does the same thing, better.
+        */
+        GF_DEPRECATED,
+        /* The 'component' is no more 'built'. */
+        GF_OBSOLETE,
+        /* The 'component' exist for Documentation purposes.
+           No real usecase */
+        GF_DOCUMENT_PURPOSE,
+} gf_category_t;
+
+
 static const char * const FOP_PRI_STRINGS[] = {
         "HIGH",
         "NORMAL",
diff --git a/libglusterfs/src/options.h b/libglusterfs/src/options.h
index 1aa2734162..1ce8975e79 100644
--- a/libglusterfs/src/options.h
+++ b/libglusterfs/src/options.h
@@ -134,9 +134,15 @@ typedef struct volume_options {
          */
         char *setkey;
 
-        /* The level at which the option is classified
-         */
-        opt_level_t             level;
+        /* A 'level' is about the technical depth / understanding one
+           needs to handle the option. 'category' is based on
+           quality (ie, tests, people behind it, documentation available) */
+
+        /* The level at which the option is classified */
+        opt_level_t level;
+
+        /* Flag to understand how this option is categorized */
+        gf_category_t category;
 } volume_option_t;
 
 
diff --git a/libglusterfs/src/xlator.c b/libglusterfs/src/xlator.c
index 22e3e041fd..d3c134ba90 100644
--- a/libglusterfs/src/xlator.c
+++ b/libglusterfs/src/xlator.c
@@ -417,6 +417,8 @@ int xlator_dynload_newway (xlator_t *xl)
         xl->id         = xlapi->xlator_id;
         xl->flags      = xlapi->flags;
         xl->identifier = xlapi->identifier;
+        xl->category   = xlapi->category;
+
         memcpy (xl->op_version, xlapi->op_version,
                 sizeof (uint32_t) * GF_MAX_RELEASES);
 
diff --git a/libglusterfs/src/xlator.h b/libglusterfs/src/xlator.h
index d476cf2644..e0b8207444 100644
--- a/libglusterfs/src/xlator.h
+++ b/libglusterfs/src/xlator.h
@@ -1051,7 +1051,8 @@ struct _xlator {
         /* flag to avoid recall of xlator_mem_cleanup for xame xlator */
         uint32_t call_cleanup;
 
-
+        /* Flag to understand how this xlator is categorized */
+        gf_category_t category;
 };
 
 typedef struct {
@@ -1092,6 +1093,9 @@ typedef struct {
            volume file, then that should be defined here. optional. */
         volume_option_t *options;
 
+        /* Flag to understand how this xlator is categorized */
+        gf_category_t category;
+
         /* XXX: GD2MARKER
          * If a new member that needs to be visible to GD2 is introduced,
          * add it above this comment.