* bfs_{read|write}_pages() now only try to lock - this fixes a possible

deadlock whenever someone without a lock (like the page_writer()) is calling
  this function.
* Added a new ReadWriteLock::TryLock() method.
* Renamed bfs_read_vnode() and bfs_release_vnode() to bfs_get_vnode() and
  bfs_put_vnode() just like those functions are called in fs_interface.h.
* Fixed a warning in BPlusTree::_SplitNode().


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@22372 a95241bf-73f2-0310-859d-f6bbb57e9c96

src/add-ons/kernel/file_systems/bfs/BPlusTree.cpp

@@ -1002,7 +1002,7 @@ BPlusTree::_SplitNode(bplustree_node *node, off_t nodeOffset,
 	int32 keyIndex = *_keyIndex;	// can become less than zero!
 
 	if (keyIndex > node->NumKeys()) {
-		FATAL(("key index out of bounds: %d, num keys: %d\n", keyIndex,
+		FATAL(("key index out of bounds: %ld, num keys: %u\n", keyIndex,
 			node->NumKeys()));
 		return B_BAD_VALUE;
 	}

src/add-ons/kernel/file_systems/bfs/Lock.h

@@ -16,7 +16,7 @@
 
 
 // Configure here if and when real benaphores should be used
-#define USE_BENAPHORE
+//#define USE_BENAPHORE
 	// if defined, benaphores are used for the Semaphore/RecursiveLock classes
 //#	define FAST_LOCK
 	// the ReadWriteLock class uses a second Semaphore to
@@ -285,16 +285,16 @@ class ReadWriteLock {
 		{
 			if (atomic_add(&fCount, -1) <= 0)
 				return acquire_sem(fSemaphore);
-			
+
 			return B_OK;
 		}
-		
+
 		void Unlock()
 		{
 			if (atomic_add(&fCount, 1) < 0)
 				release_sem(fSemaphore);
 		}
-		
+
 		status_t LockWrite()
 		{
 			if (fWriteLock.Lock() < B_OK)
@@ -313,7 +313,7 @@ class ReadWriteLock {
 
 			return status;
 		}
-		
+
 		void UnlockWrite()
 		{
 			int32 readers = atomic_add(&fCount, MAX_READERS);
@@ -377,7 +377,18 @@ class ReadWriteLock {
 			}
 			return acquire_sem(fSemaphore);
 		}
-		
+
+		status_t TryLock()
+		{
+			// This allows nested locking when holding a write lock
+			thread_id currentThread = find_thread(NULL);
+			if (currentThread == fOwner) {
+				fOwnerCount++;
+				return B_OK;
+			}
+			return acquire_sem_etc(fSemaphore, 1, B_RELATIVE_TIMEOUT, 0);
+		}
+
 		void Unlock()
 		{
 			thread_id currentThread = find_thread(NULL);
@@ -386,7 +397,7 @@ class ReadWriteLock {
 
 			release_sem(fSemaphore);
 		}
-		
+
 		status_t LockWrite()
 		{
 			thread_id currentThread = find_thread(NULL);
@@ -401,7 +412,7 @@ class ReadWriteLock {
 			}
 			return status;
 		}
-		
+
 		void UnlockWrite()
 		{
 			if (--fOwnerCount == 0) {

src/add-ons/kernel/file_systems/bfs/kernel_interface.cpp

@@ -225,11 +225,10 @@ bfs_sync(void *_ns)
 //	#pragma mark -
 
 
-/**	Reads in the node from disk and creates an inode object from it.
- */
-
+/*!	Reads in the node from disk and creates an inode object from it.
+*/
 static status_t
-bfs_read_vnode(void *_ns, ino_t id, void **_node, bool reenter)
+bfs_get_vnode(void *_ns, ino_t id, void **_node, bool reenter)
 {
 	//FUNCTION_START(("ino_t = %Ld\n", id));
 	Volume *volume = (Volume *)_ns;
@@ -271,11 +270,9 @@ bfs_read_vnode(void *_ns, ino_t id, void **_node, bool reenter)
 
 
 static status_t
-bfs_release_vnode(void *_ns, void *_node, bool reenter)
+bfs_put_vnode(void *_volume, void *_node, bool reenter)
 {
-	//FUNCTION_START(("node = %p\n", _node));
-
-	Volume *volume = (Volume *)_ns;
+	Volume *volume = (Volume *)_volume;
 	Inode *inode = (Inode *)_node;
 
 	// since a directory's size can be changed without having it opened,
@@ -292,8 +289,7 @@ bfs_release_vnode(void *_ns, void *_node, bool reenter)
 	}
 
 	delete inode;
-
-	return B_NO_ERROR;
+	return B_OK;
 }
 
 
@@ -353,11 +349,13 @@ bfs_read_pages(fs_volume _fs, fs_vnode _node, fs_cookie _cookie, off_t pos,
 	if (inode->FileCache() == NULL)
 		RETURN_ERROR(B_BAD_VALUE);
 
-	if (!reenter)
-		inode->Lock().Lock();
+	if (!reenter) {
+		if (inode->Lock().TryLock() < B_OK)
+			return B_BUSY;
+	}
 
-	status_t status = file_cache_read_pages(inode->FileCache(), pos, vecs, count,
-		_numBytes);
+	status_t status = file_cache_read_pages(inode->FileCache(), pos, vecs,
+		count, _numBytes);
 
 	if (!reenter)
 		inode->Lock().Unlock();
@@ -375,11 +373,13 @@ bfs_write_pages(fs_volume _fs, fs_vnode _node, fs_cookie _cookie, off_t pos,
 	if (inode->FileCache() == NULL)
 		RETURN_ERROR(B_BAD_VALUE);
 
-	if (!reenter)
-		inode->Lock().Lock();
+	if (!reenter) {
+		if (inode->Lock().TryLock() < B_OK)
+			return B_BUSY;
+	}
 
-	status_t status = file_cache_write_pages(inode->FileCache(), pos, vecs, count,
-		_numBytes);
+	status_t status = file_cache_write_pages(inode->FileCache(), pos, vecs,
+		count, _numBytes);
 
 	if (!reenter)
 		inode->Lock().Unlock();
@@ -2161,8 +2161,8 @@ static file_system_module_info sBeFileSystem = {
 	/* vnode operations */
 	&bfs_lookup,
 	&bfs_get_vnode_name,
-	&bfs_read_vnode,
-	&bfs_release_vnode,
+	&bfs_get_vnode,
+	&bfs_put_vnode,
 	&bfs_remove_vnode,
 
 	/* VM file access */