* Split the Node references and referrers concepts. One can now have a

reference without being a referring entry.
* Reworked entry renaming. We do now remove the original entry first and
  then create a target entry. Renaming directories didn't work before since
  there would temporarily have been two links to a directory, which is not
  allowed. Replacing an entry was also broken: The original entry was not
  removed. Due to reversing the entry creation/deletion order we also do no
  longer suffer from the Tracker bug, that entries would disappear from
  queries when being renamed.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@20204 a95241bf-73f2-0310-859d-f6bbb57e9c96

src/tests/add-ons/kernel/file_systems/userlandfs/r5/src/test/ramfs/Directory.cpp

@@ -32,7 +32,7 @@ Directory::~Directory()
 status_t
 Directory::Link(Entry *entry)
 {
-	if (GetRefCount() == 0)
+	if (fReferrers.IsEmpty())
 		return Node::Link(entry);
 	return B_IS_A_DIRECTORY;
 }

src/tests/add-ons/kernel/file_systems/userlandfs/r5/src/test/ramfs/Node.cpp

@@ -80,23 +80,44 @@ Node::InitCheck() const
 	return (fVolume && fID >= 0 ? B_OK : B_NO_INIT);
 }
 
+// AddReference
+status_t
+Node::AddReference()
+{
+	if (++fRefCount == 1) {
+		status_t error = GetVolume()->NewNode(this);
+		if (error != B_OK) {
+			fRefCount--;
+			return error;
+		}
+
+		fIsKnownToVFS = true;
+	}
+
+	return B_OK;
+}
+	
+// RemoveReference
+void
+Node::RemoveReference()
+{
+	if (--fRefCount == 0) {
+		GetVolume()->RemoveNode(this);
+		fRefCount++;
+	}
+}
+
 // Link
 status_t
 Node::Link(Entry *entry)
 {
 PRINT(("Node[%Ld]::Link(): %ld ->...\n", fID, fRefCount));
-	status_t error = B_OK;
 	fReferrers.Insert(entry);
-	if (++fRefCount == 1) {
-//		error = GetVolume()->NodeAdded(this);
-		error = GetVolume()->NewNode(this);
-		if (error == B_OK)
-			fIsKnownToVFS = true;
-		else {
-			fRefCount--;
-			fReferrers.Remove(entry);
-		}
-	}
+
+	status_t error = AddReference();
+	if (error != B_OK)
+		fReferrers.Remove(entry);
+
 	return error;
 }
 
@@ -105,16 +126,10 @@ status_t
 Node::Unlink(Entry *entry)
 {
 PRINT(("Node[%Ld]::Unlink(): %ld ->...\n", fID, fRefCount));
-	status_t error = B_OK;
-	if (--fRefCount == 0) {
-//		error = GetVolume()->NodeRemoved(this);
-		error = GetVolume()->RemoveNode(this);
-		if (error != B_OK)
-			fRefCount++;
-	}
-	if (error == B_OK)
-		fReferrers.Remove(entry);
-	return error;
+	RemoveReference();
+	fReferrers.Remove(entry);
+
+	return B_OK;
 }
 
 // SetMTime

src/tests/add-ons/kernel/file_systems/userlandfs/r5/src/test/ramfs/Node.h

@@ -41,9 +41,12 @@ public:
 
 	inline vnode_id GetID() const	{ return fID; }
 
+	status_t AddReference();
+	void RemoveReference();
+	int32 GetRefCount()	{ return fRefCount; }
+
 	virtual status_t Link(Entry *entry);
 	virtual status_t Unlink(Entry *entry);
-	int32 GetRefCount()	{ return fRefCount; }
 
 	inline bool IsDirectory() const	{ return S_ISDIR(fMode); }
 	inline bool IsFile() const		{ return S_ISREG(fMode); }

src/tests/add-ons/kernel/file_systems/userlandfs/r5/src/test/ramfs/kernel_interface.cpp

@@ -873,15 +873,18 @@ ramfs_rename(void *ns, void *_oldDir, const char *oldName,
 	Directory *oldDir = dynamic_cast<Directory*>((Node*)_oldDir);
 	Directory *newDir = dynamic_cast<Directory*>((Node*)_newDir);
 	status_t error = B_OK;
+
 	// check name
 	if (!oldName || *oldName == '\0'
 		|| !strcmp(oldName, ".")  || !strcmp(oldName, "..")
 		|| !newName || *newName == '\0'
 		|| !strcmp(newName, ".")  || !strcmp(newName, "..")) {
 		SET_ERROR(error, B_BAD_VALUE);
+
 	// check nodes
 	} else if (!oldDir || !newDir) {
 		SET_ERROR(error, B_BAD_VALUE);
+
 	// check if the entry isn't actually moved or renamed
 	} else if (oldDir == newDir && !strcmp(oldName, newName)) {
 		SET_ERROR(error, B_BAD_VALUE);
@@ -890,14 +893,17 @@ FUNCTION(("old dir: %Ld, old name: `%s', new dir: %Ld, new name: `%s'\n",
 oldDir->GetID(), oldName, newDir->GetID(), newName));
 		NodeMTimeUpdater mTimeUpdater1(oldDir);
 		NodeMTimeUpdater mTimeUpdater2(newDir);
+
 		// target directory deleted?
 		if (is_vnode_removed(volume->GetID(), newDir->GetID()) > 0)
 			SET_ERROR(error, B_NOT_ALLOWED);
+
 		// check directory write permissions
 		if (error == B_OK)
 			error = oldDir->CheckPermissions(ACCESS_W);
 		if (error == B_OK)
 			error = newDir->CheckPermissions(ACCESS_W);
+
 		Node *node = NULL;
 		Entry *entry = NULL;
 		if (error == B_OK) {
@@ -919,6 +925,7 @@ oldDir->GetID(), oldName, newDir->GetID(), newName));
 					}
 				}
 			}
+
 			// check the target directory situation
 			Node *clobberNode = NULL;
 			Entry *clobberEntry = NULL;
@@ -931,33 +938,47 @@ oldDir->GetID(), oldName, newDir->GetID(), newName));
 					}
 				}
 			}
+
 			// do the job
 			if (error == B_OK) {
-				if (clobberEntry) {
-					error = clobberEntry->Link(node);
-					// notify listeners
+				// temporarily acquire an additional reference to make
+				// sure the node isn't deleted when we remove the entry
+				error = node->AddReference();
+				if (error == B_OK) {
+					// delete the original entry
+					error = oldDir->DeleteEntry(entry);
 					if (error == B_OK) {
-						notify_listener(B_ENTRY_REMOVED,
-							volume->GetID(), newDir->GetID(), 0,
-							clobberNode->GetID(), NULL);
-					}
-				} else {
-					Entry *newEntry = NULL;
-// TODO: If the node is a directory, this does fail!!!
-					error = newDir->CreateEntry(node, newName, &newEntry);
-					if (error == B_OK) {
-						error = oldDir->DeleteEntry(entry);
-						if (error != B_OK)
-							newDir->DeleteEntry(newEntry);
+						// create the new one/relink the target entry
+						if (clobberEntry)
+							error = clobberEntry->Link(node);
+						else
+							error = newDir->CreateEntry(node, newName);
+
+						if (error == B_OK) {
+							// send a "removed" notification for the clobbered
+							// entry
+							if (clobberEntry) {
+								notify_listener(B_ENTRY_REMOVED,
+									volume->GetID(), newDir->GetID(), 0,
+									clobberNode->GetID(), newName);
+							}
+						} else {
+							// try to recreate the original entry, in case of
+							// failure
+							newDir->CreateEntry(node, oldName);
+						}
 					}
+					node->RemoveReference();
 				}
 			}
+
 			// release the entries
 			if (clobberEntry)
 				volume->PutNode(clobberNode);
 			if (entry)
 				volume->PutNode(node);
 		}
+
 		// notify listeners
 		if (error == B_OK) {
 			notify_listener(B_ENTRY_MOVED, volume->GetID(), oldDir->GetID(),
@@ -965,6 +986,7 @@ oldDir->GetID(), oldName, newDir->GetID(), newName));
 		}
 	} else
 		SET_ERROR(error, B_ERROR);
+
 	RETURN_ERROR(error);
 }