crush: add PUSHOP feature bit

Set the PUSHPOP feature bit while encoding if we use any of the new
PUSH/POP/SHIFT/UNSHIF rule ops.

Signed-off-by: Sage Weil <sage.weil@dreamhost.com>

2 files changed, 23 insertions, 0 deletions

diff --git a/src/crush/CrushWrapper.h b/src/crush/CrushWrapper.h
index 11357d5ec99..c94536f3af1 100644
--- a/src/crush/CrushWrapper.h
+++ b/src/crush/CrushWrapper.h
@@ -409,12 +409,29 @@ public:
     return bl.write_file(fn);
   }
 
+  void calc_features() {
+    // see if we have any rules that use push|pop|shift|unshift
+    for (unsigned i=0; i<crush->max_rules; ++i) {
+      crush_rule *r = crush->rules[i];
+      if (r == NULL)
+	continue;
+      for (unsigned j=0; j<r->len; ++j) {
+	if (r->steps[j].op == CRUSH_RULE_PUSH ||
+	    r->steps[j].op == CRUSH_RULE_POP ||
+	    r->steps[j].op == CRUSH_RULE_SHIFT ||
+	    r->steps[j].op == CRUSH_RULE_UNSHIFT)
+	  crush->features |= CRUSH_FEATURE_PUSHPOP;
+      }
+    }
+  }
+
   void encode(bufferlist &bl, bool lean=false) {
     if (!crush) create();  // duh.
 
     __u16 struct_v = 1;
     ::encode(struct_v, bl);
 
+    calc_features();
     ::encode(crush->features, bl);
 
     ::encode(crush->max_buckets, bl);
diff --git a/src/crush/crush.h b/src/crush/crush.h
index 8595f88b1a2..0c60920a0f8 100644
--- a/src/crush/crush.h
+++ b/src/crush/crush.h
@@ -17,7 +17,9 @@
  */
 
 
+#define CRUSH_FEATURE_PUSHPOP  (1<<0)
 
+#define CRUSH_FEATURE_ALL      (CRUSH_FEATURE_PUSHPOP)
 
 #define CRUSH_MAX_DEPTH 10  /* max crush hierarchy depth */
 #define CRUSH_MAX_SET   10  /* max size of a mapping result */
@@ -150,6 +152,10 @@ struct crush_bucket_straw {
  * CRUSH map includes all buckets, rules, etc.
  */
 struct crush_map {
+	/*
+	 * Bit mask indicating which CRUSH_FEATURE_* features are used
+	 * by this map.
+	 */
 	__u16 features;
 
 	struct crush_bucket **buckets;