From: sage <sage@29311d96-e01e-0410-9327-a35deaab8ce9>
Date: Tue, 28 Jun 2005 16:41:31 +0000 (+0000)
Subject: *** empty log message ***
X-Git-Tag: v0.1~2025
X-Git-Url: http://git-server-git.apps.pok.os.sepia.ceph.com/?a=commitdiff_plain;h=ac9d0d44c18f9751387819c493ef4d2e6786f96f;p=ceph.git

*** empty log message ***


git-svn-id: https://ceph.svn.sf.net/svnroot/ceph@356 29311d96-e01e-0410-9327-a35deaab8ce9
---

diff --git a/ceph/client/Buffercache.h b/ceph/client/Buffercache.h
index 62b4ae3c00433..fa30708a822ec 100644
--- a/ceph/client/Buffercache.h
+++ b/ceph/client/Buffercache.h
@@ -16,6 +16,17 @@
 class Buffercache;
 
 class Bufferhead : public LRUObject {
+  // reference counter
+  int ref;  
+  void get() {
+	if (ref == 0) lru_pin();
+	++ref;
+  }
+  void put() {
+	--ref;
+	if (ref == 0) lru_unpin();
+  }
+
  public: // FIXME: make more private and write some accessors
   off_t offset;
   size_t len;
@@ -30,6 +41,7 @@ class Bufferhead : public LRUObject {
   
   // cons/destructors
   Bufferhead(inodeno_t ino, off_t off, size_t len, Buffercache *bc, int state=BUFHD_STATE_CLEAN) {
+	this->ref = 0;
     this->ino = ino;
     this->offset = off;
 	this->len = len;
@@ -40,28 +52,32 @@ class Bufferhead : public LRUObject {
   }
   
   ~Bufferhead() {
-    list<bufferptr> bl = bh->bl.buffers();
-    for (list<bufferptr>::iterator it == bl.begin();
-         it != bl.end();
-         it++) {
-      delete *it;
-    }
+	// no need to delete bufferlist bufferptr's explicitly; ~list() does that (since it's list<bufferptr>, not list<bufferptr*>)
   }
   
   //Bufferhead(inodeno_t ino, off_t off, size_t len, int state);
   
   // ~Bufferhead(); FIXME: need to mesh with allocator scheme
 
-  void add_read_waiter(Cond *cond) {
-    read_waiters->push_back(cond); 
-	lru_pin(); 
+
+  // -- wait for read, write: these will block
+  // i think this will work okay?  and reference coutning in the waiter makes sure the wakeup fn doesn't 
+  // inadvertantly unpin the bufferhead before the waiters get to go
+  void wait_for_read(Mutex& lock) {
+	Cond cond;  // on local stack
+	get();
+	read_waiters.push_back(&cond);
+	cond.Wait(lock);
+	put();
   }
-  
-  void add_write_waiter(Cond *cond) { 
-    write_waiters->push_back(cond); 
-	lru_pin(); 
+  void wait_for_write(Mutex& lock) {
+	Cond cond;  // on local stack
+	get();
+	write_waiters.push_back(&cond);
+	cond.Wait(lock);
+	put();  
   }
-  
+
   void wakeup_read_waiters() { 
     for (list<Cond*>::iterator it = read_waiters.begin();
 		 it != read_waiters.end();
@@ -69,7 +85,6 @@ class Bufferhead : public LRUObject {
 	  (*it)->Signal();
 	}
     read_waiters.clear(); 
-	if (write_waiters.empty()) lru_unpin(); 
   }
   
   void wakeup_write_waiters() {
@@ -78,8 +93,6 @@ class Bufferhead : public LRUObject {
 		 it++) {
 	  (*it)->Signal();
 	}
-    write_waiters.clear(); 
-	if (read_waiters.empty()) lru_unpin(); 
   }
   
   void miss_start() {