thin: update thin feature detection

Safe 1 static var and keep whole detection within one function.

diff --git a/lib/thin/thin.c b/lib/thin/thin.c
index 18b819b5d3669c1ed0a90807421fcd2ba3c04486..d7c45ca16a1b519b91d5b6c413efbc42a8d8902c 100644 (file)
--- a/lib/thin/thin.c
+++ b/lib/thin/thin.c
@@ -37,23 +37,8 @@
        log_error(t " segment %s of logical volume %s.", ## p, \
                  dm_config_parent_name(sn), seg->lv->name), 0;
 
-/* List of features with their kernel target version */
-static const struct feature {
-       uint32_t maj;
-       uint32_t min;
-       unsigned thin_feature;
-       const char *feature;
-} _features[] = {
-       { 1, 1, THIN_FEATURE_DISCARDS, "discards" },
-       { 1, 1, THIN_FEATURE_EXTERNAL_ORIGIN, "external_origin" },
-       { 1, 4, THIN_FEATURE_BLOCK_SIZE, "block_size" },
-       { 1, 5, THIN_FEATURE_DISCARDS_NON_POWER_2, "discards_non_power_2" },
-};
-
-static const char _lvmconf[] = "global/thin_disabled_features";
-/* TODO: using static field heer, maybe should be part of segment_type */
+/* TODO: using static field here, maybe should be a part of segment_type */
 static unsigned _feature_mask;
-static int _log_feature_mask;
 
 static int _thin_target_present(struct cmd_context *cmd,
                                const struct lv_segment *seg,
@@ -557,11 +542,28 @@ static int _thin_target_present(struct cmd_context *cmd,
                                const struct lv_segment *seg,
                                unsigned *attributes)
 {
+       /* List of features with their kernel target version */
+       static const struct feature {
+               uint32_t maj;
+               uint32_t min;
+               unsigned thin_feature;
+               const char *feature;
+       } const _features[] = {
+               { 1, 1, THIN_FEATURE_DISCARDS, "discards" },
+               { 1, 1, THIN_FEATURE_EXTERNAL_ORIGIN, "external_origin" },
+               { 1, 4, THIN_FEATURE_BLOCK_SIZE, "block_size" },
+               { 1, 5, THIN_FEATURE_DISCARDS_NON_POWER_2, "discards_non_power_2" },
+       };
+
+       static const char _lvmconf[] = "global/thin_disabled_features";
        static int _checked = 0;
        static int _present = 0;
        static unsigned _attrs = 0;
        uint32_t maj, min, patchlevel;
        unsigned i;
+       const struct dm_config_node *cn;
+       const struct dm_config_value *cv;
+       const char *str;
 
        if (!_checked) {
                _present = target_present(cmd, THIN_MODULE, 1);
@@ -582,13 +584,32 @@ static int _thin_target_present(struct cmd_context *cmd,
        }
 
        if (attributes) {
-               if (_log_feature_mask) {
+               if (!_feature_mask) {
+                       /* Support runtime lvm.conf changes, N.B. avoid 32 feature */
+                       if ((cn = find_config_tree_node(cmd, _lvmconf))) {
+                               for (cv = cn->v; cv; cv = cv->next) {
+                                       if (cv->type != DM_CFG_STRING) {
+                                               log_error("Ignoring invalid string in config file %s.",
+                                                         _lvmconf);
+                                               continue;
+                                       }
+                                       str = cv->v.str;
+                                       if (!*str) {
+                                               log_error("Ignoring empty string in config file %s.",
+                                                         _lvmconf);
+                                               continue;
+                                       }
+                                       for (i = 0; i < sizeof(_features)/sizeof(*_features); i++)
+                                               if (strcasecmp(str, _features[i].feature) == 0)
+                                                       _feature_mask |= _features[i].thin_feature;
+                               }
+                       }
+                       _feature_mask = ~_feature_mask;
                        for (i = 0; i < sizeof(_features)/sizeof(*_features); i++)
                                if ((_attrs & _features[i].thin_feature) &&
                                    !(_feature_mask & _features[i].thin_feature))
                                        log_very_verbose("Target "THIN_MODULE " %s support disabled by %s",
                                                         _features[i].feature, _lvmconf);
-                       _log_feature_mask = 0; /* log just once */
                }
                *attributes = _attrs & _feature_mask;
        }
@@ -664,11 +685,7 @@ int init_multiple_segtypes(struct cmd_context *cmd, struct segtype_library *segl
        };
 
        struct segment_type *segtype;
-       const struct dm_config_node *cn;
-       const struct dm_config_value *cv;
-       const char *str;
        unsigned i;
-       unsigned mask = 0;
 
        for (i = 0; i < sizeof(reg_segtypes)/sizeof(reg_segtypes[0]); ++i) {
                segtype = dm_zalloc(sizeof(*segtype));
@@ -697,29 +714,9 @@ int init_multiple_segtypes(struct cmd_context *cmd, struct segtype_library *segl
                log_very_verbose("Initialised segtype: %s", segtype->name);
        }
 
-       /* Support runtime lvm.conf changes */
-       if ((cn = find_config_tree_node(cmd, _lvmconf))) {
-               for (cv = cn->v; cv; cv = cv->next) {
-                       if (cv->type != DM_CFG_STRING) {
-                               log_error("Ignoring invalid string in config file %s.",
-                                         _lvmconf);
-                               continue;
-                       }
-                       str = cv->v.str;
-                       if (!*str) {
-                               log_error("Ignoring empty string in config file %s.",
-                                         _lvmconf);
-                               continue;
-                       }
-                       for (i = 0; i < sizeof(_features)/sizeof(*_features); i++)
-                               if (strcasecmp(str, _features[i].feature) == 0)
-                                       mask |= _features[i].thin_feature;
-               }
-               _log_feature_mask = (mask != 0);
-       }
 
-       /* Store as 'and' mask in static field */
-       _feature_mask = ~mask;
+       /* Reset mask for recalc */
+       _feature_mask = 0;
 
        return 1;
 }