ALF-12866: WebDAV in-memory locking - threading issues.

* LockInfo instances provide a ReentrantReadWriteLock for clients to use
* LockInfo client code synchronises uses provided RRWLs.



git-svn-id: https://svn.alfresco.com/repos/alfresco-enterprise/alfresco/HEAD/root@34212 c4b6b30b-aa2e-2d43-bbcb-ca4b014f7261
This commit is contained in:
Matt Ward
2012-02-24 11:28:09 +00:00
parent e579b15f15
commit 894056132b
7 changed files with 368 additions and 197 deletions

View File

@@ -22,9 +22,13 @@ import java.io.Serializable;
import java.util.Date;
import java.util.HashSet;
import java.util.Set;
import java.util.concurrent.locks.ReentrantReadWriteLock;
/**
* Class to represent a WebDAV lock info
* Class to represent a WebDAV lock info. Instances of this class are accessible
* my multiple threads as they are kept in the {@link LockStore}. Clients of this
* class are expected to synchronise externally using the provided
* ReentrantReadWriteLock (use {@link #getRWLock()}).
*
* @author Ivan Rybnikov
*
@@ -33,6 +37,8 @@ public final class LockInfo implements Serializable
{
private static final long serialVersionUID = 1L;
private final ReentrantReadWriteLock rwLock = new ReentrantReadWriteLock();
// Exclusive lock token
private String exclusiveLockToken = null;
@@ -73,6 +79,20 @@ public final class LockInfo implements Serializable
this.depth = depth;
}
/**
* Retrieves the {@link ReentrantReadWriteLock} associated with this LockInfo. This is
* to allow client code to protect against invalid concurrent access to the state of
* this class.
* <p>
* Not to be confused with WebDAV locks.
*
* @return
*/
public ReentrantReadWriteLock getRWLock()
{
return rwLock;
}
/**
* Returns true if node has shared or exclusive locks
*
@@ -294,11 +314,18 @@ public final class LockInfo implements Serializable
}
/**
* Sets the expiry date/time to lockTimeout seconds into the future.
* Sets the expiry date/time to lockTimeout seconds into the future. Provide
* a lockTimeout of WebDAV.TIMEOUT_INFINITY for never expires.
*
* @param lockTimeout
*/
public void setTimeoutSeconds(int lockTimeout)
{
if (lockTimeout == WebDAV.TIMEOUT_INFINITY)
{
setExpires(null);
}
else
{
int timeoutMillis = (lockTimeout * 60 * 1000);
Date now = new Date();
@@ -306,3 +333,4 @@ public final class LockInfo implements Serializable
setExpires(nextExpiry);
}
}
}

View File

@@ -336,12 +336,13 @@ public class LockMethod extends WebDAVMethod
m_response.setStatus(HttpServletResponse.SC_CREATED);
}
// Check if this is a new lock or a lock refresh
if (hasLockToken())
{
this.lockInfo = checkNode(lockNodeInfo);
lockInfo = checkNode(lockNodeInfo);
lockInfo.getRWLock().writeLock().lock();
try
{
// If a request body is not defined and "If" header is sent we have createExclusive as false,
// but we need to check a previous LOCK was an exclusive. I.e. get the property for node. It
// is already has got in a checkNode method, so we need just get a scope from lockInfo.
@@ -350,12 +351,25 @@ public class LockMethod extends WebDAVMethod
// Refresh an existing lock
refreshLock(lockNodeInfo, userName);
}
finally
{
lockInfo.getRWLock().writeLock().unlock();
}
}
else
{
this.lockInfo = checkNode(lockNodeInfo, true, this.createExclusive);
lockInfo = checkNode(lockNodeInfo, true, createExclusive);
lockInfo.getRWLock().writeLock().lock();
try
{
// Create a new lock
createLock(lockNodeInfo, userName);
}
finally
{
lockInfo.getRWLock().writeLock().unlock();
}
}
m_response.setHeader(WebDAV.HEADER_LOCK_TOKEN, "<" + WebDAV.makeLockToken(lockNodeInfo.getNodeRef(), userName) + ">");
@@ -391,6 +405,9 @@ public class LockMethod extends WebDAVMethod
// Create Lock token
lockToken = WebDAV.makeLockToken(lockNode.getNodeRef(), userName);
lockInfo.getRWLock().writeLock().lock();
try
{
if (createExclusive)
{
// Lock the node
@@ -417,6 +434,11 @@ public class LockMethod extends WebDAVMethod
logger.debug("Locked node " + lockNode + ": " + lockInfo);
}
}
finally
{
lockInfo.getRWLock().writeLock().unlock();
}
}
/**
* Refresh an existing lock
@@ -429,11 +451,16 @@ public class LockMethod extends WebDAVMethod
{
if (this.createExclusive)
{
// Update the expiry for the lock
if (lockInfo.getExpires() != null)
lockInfo.getRWLock().writeLock().lock();
try
{
// Update the expiry for the lock
lockInfo.setTimeoutSeconds(getLockTimeout());
}
finally
{
lockInfo.getRWLock().writeLock().unlock();
}
}
}
@@ -444,6 +471,12 @@ public class LockMethod extends WebDAVMethod
{
String scope;
String lt;
String owner;
Date expiry;
lockInfo.getRWLock().readLock().lock();
try
{
if (lockToken != null)
{
// In case of lock creation take the scope from request header
@@ -458,7 +491,13 @@ public class LockMethod extends WebDAVMethod
// Output refreshed lock
lt = this.lockInfo.getExclusiveLockToken();
}
String owner = lockInfo.getOwner();
owner = lockInfo.getOwner();
expiry = lockInfo.getExpires();
}
finally
{
lockInfo.getRWLock().readLock().unlock();
}
XMLWriter xml = createXMLWriter();
@@ -468,7 +507,6 @@ public class LockMethod extends WebDAVMethod
xml.startElement(WebDAV.DAV_NS, WebDAV.XML_PROP + nsdec, WebDAV.XML_NS_PROP + nsdec, getDAVHelper().getNullAttributes());
// Output the lock details
Date expiry = lockInfo.getExpires();
generateLockDiscoveryXML(xml, lockNodeInfo, false, scope, WebDAV.getDepthName(m_depth), lt, owner, expiry);
// Close off the XML

View File

@@ -54,5 +54,11 @@ public interface LockStore
LockInfo get(NodeRef nodeRef);
/**
* Remove LockInfo for the specified NodeRef. The LockInfo cannot be considered locked
* once removed from the LockStore.
*
* @param nodeRef
*/
void remove(NodeRef nodeRef);
}

View File

@@ -924,11 +924,19 @@ public class PropFindMethod extends WebDAVMethod
// Output the lock status response
LockInfo lockInfo = getNodeLockInfo(nodeInfo);
lockInfo.getRWLock().readLock().lock();
try
{
if (lockInfo.isLocked())
{
generateLockDiscoveryXML(xml, nodeInfo, lockInfo);
}
}
finally
{
lockInfo.getRWLock().readLock().unlock();
}
}
/**
* Output the supported lock types XML element

View File

@@ -190,7 +190,12 @@ public class PutMethod extends WebDAVMethod
String userName = getDAVHelper().getAuthenticationService().getCurrentUserName();
LockInfo lockInfo = getLockStore().get(contentNodeInfo.getNodeRef());
if (lockInfo != null && lockInfo.isLocked() && !lockInfo.getOwner().equals(userName))
if (lockInfo != null)
{
lockInfo.getRWLock().readLock().lock();
try
{
if (lockInfo.isLocked() && !lockInfo.getOwner().equals(userName))
{
if (logger.isDebugEnabled())
{
@@ -201,6 +206,12 @@ public class PutMethod extends WebDAVMethod
// Indicate that the resource is locked
throw new WebDAVServerException(WebDAV.WEBDAV_SC_LOCKED);
}
}
finally
{
lockInfo.getRWLock().readLock().unlock();
}
}
try
{

View File

@@ -132,7 +132,20 @@ public class UnlockMethod extends WebDAVMethod
NodeRef nodeRef = lockNodeInfo.getNodeRef();
LockInfo lockInfo = getLockStore().get(nodeRef);
if (lockInfo == null || !lockInfo.isLocked())
if (lockInfo == null)
{
if (logger.isDebugEnabled())
{
logger.debug("Unlock token=" + getLockToken() + " Not locked - no info in lock store.");
}
// Node is not locked
throw new WebDAVServerException(HttpServletResponse.SC_PRECONDITION_FAILED);
}
lockInfo.getRWLock().writeLock().lock();
try
{
if (!lockInfo.isLocked())
{
if (logger.isDebugEnabled())
{
@@ -200,6 +213,11 @@ public class UnlockMethod extends WebDAVMethod
throw new IllegalStateException("Invalid LockInfo state: " + lockInfo);
}
}
finally
{
lockInfo.getRWLock().writeLock().unlock();
}
}
// This method removes a new zero byte node that has been locked, where the
// PUT has not taken place but the client has issued an UNLOCK. The Timer

View File

@@ -751,9 +751,23 @@ public abstract class WebDAVMethod
*/
protected void generateLockDiscoveryXML(XMLWriter xml, FileInfo lockNodeInfo, LockInfo lockInfo) throws Exception
{
String owner = lockInfo.getOwner();
Date expiry = lockInfo.getExpires();
generateLockDiscoveryXML(xml, lockNodeInfo, false, lockInfo.getScope(), lockInfo.getDepth(),
String owner, scope, depth;
Date expiry;
lockInfo.getRWLock().readLock().lock();
try
{
owner = lockInfo.getOwner();
expiry = lockInfo.getExpires();
scope = lockInfo.getScope();
depth = lockInfo.getDepth();
}
finally
{
lockInfo.getRWLock().readLock().unlock();
}
generateLockDiscoveryXML(xml, lockNodeInfo, false, scope, depth,
WebDAV.makeLockToken(lockNodeInfo.getNodeRef(), owner), owner, expiry);
}
@@ -873,6 +887,10 @@ public abstract class WebDAVMethod
protected LockInfo checkNode(FileInfo fileInfo, boolean ignoreShared, boolean lockMethod) throws WebDAVServerException
{
LockInfo nodeLockInfo = getNodeLockInfo(fileInfo);
nodeLockInfo.getRWLock().readLock().lock();
try
{
String nodeETag = getDAVHelper().makeQuotedETag(fileInfo);
@@ -928,6 +946,11 @@ public abstract class WebDAVMethod
return nodeLockInfo;
}
finally
{
nodeLockInfo.getRWLock().readLock().unlock();
}
}
/**
* Checks if write operation can be performed on node.
@@ -945,13 +968,15 @@ public abstract class WebDAVMethod
/**
* Checks if node can be accessed with WebDAV operation
*
* @param nodeLockToken - token to check
* @param lockInfo - node's lock info
* @param ignoreShared - if true - ignores shared lock tokens
* @param lockMethod - must be true if used from lock method
* @throws WebDAVServerException if node has no appropriate lock token
*/
private void checkLockToken(LockInfo lockInfo, boolean ignoreShared, boolean lockMethod) throws WebDAVServerException
{
lockInfo.getRWLock().readLock().lock();
try
{
String nodeLockToken = lockInfo.getExclusiveLockToken();
Set<String> sharedLockTokens = lockInfo.getSharedLockTokens();
@@ -1013,6 +1038,11 @@ public abstract class WebDAVMethod
throw new WebDAVServerException(WebDAV.WEBDAV_SC_LOCKED);
}
}
}
finally
{
lockInfo.getRWLock().readLock().unlock();
}
throw new WebDAVServerException(WebDAV.WEBDAV_SC_LOCKED);
}
@@ -1136,10 +1166,21 @@ public abstract class WebDAVMethod
lockInfo = m_parentLockInfo.get(parent);
if ((lockInfo != null) && (lockInfo.isLocked()))
if (lockInfo != null)
{
lockInfo.getRWLock().readLock().lock();
try
{
if (lockInfo.isLocked())
{
return lockInfo;
}
}
finally
{
lockInfo.getRWLock().readLock().unlock();
}
}
if (lockInfo == null)
{
@@ -1177,13 +1218,25 @@ public abstract class WebDAVMethod
{
LockInfo lock = getLockStore().get(nodeInfo.getNodeRef());
if (lock != null && lock.isLocked())
if (lock == null)
{
return null;
}
lock.getRWLock().readLock().lock();
try
{
if (lock.isLocked())
{
return lock;
}
return null;
}
finally
{
lock.getRWLock().readLock().unlock();
}
}
/**
* Checks whether a parent node has a lock that is valid for all its descendants.
@@ -1195,18 +1248,27 @@ public abstract class WebDAVMethod
{
LockInfo parentLock = getLockStore().get(parent);
if (parentLock != null && WebDAV.INFINITY.equals(parentLock.getDepth()))
if (parentLock == null)
{
return null;
}
parentLock.getRWLock().readLock().lock();
try
{
// now check for lock status ...
if (parentLock.isLocked())
if (parentLock.isLocked() && WebDAV.INFINITY.equals(parentLock.getDepth()))
{
// In this case node is locked indirectly.
return parentLock;
}
}
return null;
}
finally
{
parentLock.getRWLock().readLock().unlock();
}
}
/**
* Get the file info for the given paths