From: Greg Farnum <gregf@hq.newdream.net>
Date: Thu, 29 Apr 2010 23:00:10 +0000 (-0700)
Subject: mds: implement look_for_lock, for fcntl F_GETLK-style things
X-Git-Tag: v0.22~346^2~26
X-Git-Url: http://git-server-git.apps.pok.os.sepia.ceph.com/?a=commitdiff_plain;h=0dbcdd848628e7222895cff1688d98d88067622a;p=ceph.git

mds: implement look_for_lock, for fcntl F_GETLK-style things
---

diff --git a/src/mds/Server.cc b/src/mds/Server.cc
index f6f10d2f48d..32a136e3702 100644
--- a/src/mds/Server.cc
+++ b/src/mds/Server.cc
@@ -2660,7 +2660,7 @@ void Server::handle_client_file_readlock(MDRequest *mdr)
 	    << ", dropping request!" << dendl;
     return;
   }
-  lock_state->add_lock(checking_lock, false, false);
+  lock_state->look_for_lock(checking_lock);
 
   bufferlist lock_bl;
   ::encode(lock_state, lock_bl);
diff --git a/src/mds/mdstypes.h b/src/mds/mdstypes.h
index 8f29b1c5596..112d5f0b6e4 100644
--- a/src/mds/mdstypes.h
+++ b/src/mds/mdstypes.h
@@ -385,6 +385,28 @@ struct ceph_lock_state_t {
     return false;
   }
 
+  void look_for_lock(ceph_filelock& testing_lock) {
+    list<ceph_filelock*> overlapping_locks, self_overlapping_locks;
+    if (get_overlapping_locks(testing_lock, overlapping_locks)) {
+      split_by_owner(testing_lock, overlapping_locks, self_overlapping_locks);
+    }
+    if (!overlapping_locks.empty()) { //somebody else owns overlapping lock
+      if (CEPH_LOCK_EXCL == testing_lock.type) { //any lock blocks it
+	testing_lock = *(*overlapping_locks.begin());
+      } else {
+	ceph_filelock *blocking_lock;
+	if ((blocking_lock = contains_exclusive_lock(overlapping_locks))) {
+	  testing_lock = *blocking_lock;
+	} else { //nothing blocking!
+	  testing_lock.type = CEPH_LOCK_UNLOCK;
+	}
+      }
+      return;
+    }
+    //if we get here, only our own locks block
+    testing_lock.type = CEPH_LOCK_UNLOCK;
+  }
+
   /*
    * Remove lock(s) described in old_lock. This may involve splitting a
    * previous lock or making a previous lock smaller.
@@ -659,13 +681,13 @@ private:
     }
   }
 
-  bool contains_exclusive_lock(list<ceph_filelock*>& locks) {
+  ceph_filelock *contains_exclusive_lock(list<ceph_filelock*>& locks) {
     for (list<ceph_filelock*>::iterator iter = locks.begin();
 	 iter != locks.end();
 	 ++iter) {
-      if (CEPH_LOCK_EXCL == (*iter)->type) return true;
+      if (CEPH_LOCK_EXCL == (*iter)->type) return *iter;
     }
-    return false;
+    return NULL;
   }
 
 public: