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http://issues.apache.org/bugzilla/show_bug.cgi?id=37374 Summary: Deadly embrace between AbstractFileProvider and SoftRefFilesCache Product: Commons Version: unspecified Platform: All OS/Version: All Status: NEW Severity: critical Priority: P2 Component: VFS AssignedTo: commons-dev@jakarta.apache.org ReportedBy: [EMAIL PROTECTED] Lock contention occurs when one thread attempts to retreave a FileSystem from the cache at the same time that the SoftRefFilesCache thread is attempting to close a FileSystem. SoftRefFilesCache locaks itself and then calls FileSystem.close(), which attempts to acquire a lock on the AbstractFileProvider. AbstractFileProvider locks itself before calling SoftRefFilesCache. To fix: 1) Remove 'synchronized' from AbstractLayeredFileProvider.createfileSystem() 2) Replace AbstractFileProvider with the following: /* * Copyright 2002-2005 The Apache Software Foundation. * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package org.apache.commons.vfs.provider; import java.util.Collections; import java.util.Map; import java.util.TreeMap; import org.apache.commons.vfs.FileName; import org.apache.commons.vfs.FileObject; import org.apache.commons.vfs.FileSystem; import org.apache.commons.vfs.FileSystemConfigBuilder; import org.apache.commons.vfs.FileSystemException; import org.apache.commons.vfs.FileSystemOptions; import org.apache.commons.vfs.provider.local.GenericFileNameParser; /** * A partial [EMAIL PROTECTED] FileProvider} implementation. Takes care of managing the * file systems created by the provider. * * @author <a href="mailto:[EMAIL PROTECTED]">Adam Murdoch</a> * @version $Revision: 191323 $ $Date: 2005-06-19 03:25:16 -0400 (Sun, 19 Jun 2005) $ */ public abstract class AbstractFileProvider extends AbstractVfsContainer implements FileProvider { private FileNameParser parser; public AbstractFileProvider() { parser = GenericFileNameParser.getInstance(); } protected FileNameParser getFileNameParser() { return parser; } protected void setFileNameParser(FileNameParser parser) { this.parser = parser; } /** * The cached file systems. This is a mapping from root URI to * FileSystem object. */ // private final Map fileSystems = new HashMap(); private final Map fileSystems = Collections.synchronizedMap(new TreeMap()); /** * Closes the file systems created by this provider. */ public void close() { fileSystems.clear(); super.close(); } /** * Creates a layered file system. This method throws a 'not supported' exception. */ public FileObject createFileSystem(final String scheme, final FileObject file, final FileSystemOptions properties) throws FileSystemException { // Can't create a layered file system throw new FileSystemException("vfs.provider/not-layered-fs.error", scheme); } /** * Adds a file system to those cached by this provider. The file system * may implement [EMAIL PROTECTED] VfsComponent}, in which case it is initialised. */ protected void addFileSystem(final Comparable key, final FileSystem fs) throws FileSystemException { // Add to the cache addComponent(fs); FileSystemKey treeKey = new FileSystemKey(key, fs.getFileSystemOptions()); ((AbstractFileSystem) fs).setCacheKey(treeKey); fileSystems.put(treeKey, fs); } /** * Locates a cached file system * * @return The provider, or null if it is not cached. */ protected FileSystem findFileSystem(final Comparable key, final FileSystemOptions fileSystemProps) { FileSystemKey treeKey = new FileSystemKey(key, fileSystemProps); return (FileSystem) fileSystems.get(treeKey); } public FileSystemConfigBuilder getConfigBuilder() { return null; } public void freeUnusedResources() { Object[] item = fileSystems.values().toArray(); for (int i = 0; i < item.length; ++i) { AbstractFileSystem fs = (AbstractFileSystem) item[i]; if (fs.isReleaseable()) { fs.closeCommunicationLink(); } } } public void closeFileSystem(final FileSystem filesystem) { AbstractFileSystem fs = (AbstractFileSystem) filesystem; fileSystems.remove(fs.getCacheKey()); removeComponent(fs /*fileSystems*/); fs.close(); } /** * Parses an absolute URI. * * @param base The base file - if null the <code>uri</code> needs to be absolute * @param uri The URI to parse. */ public FileName parseUri(FileName base, String uri) throws FileSystemException { if (getFileNameParser() != null) { return getFileNameParser().parseUri(getContext(), base, uri); } throw new FileSystemException("vfs.provider/filename-parser-missing.error"); // return GenericFileName.parseUri(getFileNameParser(), uri, 0); } } -- Configure bugmail: http://issues.apache.org/bugzilla/userprefs.cgi?tab=email ------- You are receiving this mail because: ------- You are the assignee for the bug, or are watching the assignee. --------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
