mds/SimpleLock: add is_xlocked_by()

This eliminates more reference counter manipulations.

Signed-off-by: Max Kellermann <[email protected]>

Author: MaxKellermann

src/mds/CDentry.h

@@ -232,7 +232,7 @@ class CDentry : public MDSCacheObject, public LRUObject, public Counter<CDentry>
 
   bool use_projected(client_t client, const MutationRef& mut) const {
     return lock.can_read_projected(client) || 
-      lock.get_xlock_by() == mut;
+      lock.is_xlocked_by(mut);
   }
   linkage_t *get_linkage(client_t client, const MutationRef& mut) {
     return use_projected(client, mut) ? get_projected_linkage() : get_linkage();

src/mds/MDCache.cc

@@ -8524,7 +8524,7 @@ int MDCache::path_traverse(const MDRequestRef& mdr, MDSContextFactory& cf,
 	}
       } else if (!path_locked &&
 		 !dn->lock.can_read(client) &&
-		 !(dn->lock.is_xlocked() && dn->lock.get_xlock_by() == mdr)) {
+		 !(dn->lock.is_xlocked() && dn->lock.is_xlocked_by(mdr))) {
 	dout(10) << "traverse: non-readable dentry at " << *dn << dendl;
 	dn->lock.add_waiter(SimpleLock::WAIT_RD, cf.build());
 	if (mds->logger)

src/mds/SimpleLock.h

@@ -468,6 +468,9 @@ class SimpleLock {
   bool has_xlock_by() const noexcept {
     return have_more() && more()->xlock_by;
   }
+  bool is_xlocked_by(const MutationRef &who) const noexcept {
+    return have_more() && more()->xlock_by == who;
+  }
 
   // lease
   bool is_leased() const {