alluxio.master.file.meta

Class MountTable

java.lang.Object

alluxio.master.file.meta.MountTable

All Implemented Interfaces:

Checkpointed, DelegatingJournaled, Journaled, JournalEntryIterable

@ThreadSafe
public final class MountTable
extends Object
implements DelegatingJournaled

This class is used for keeping track of Alluxio mount points.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	MountTable.Resolution This class represents a UFS path after resolution.
static class	MountTable.ReverseResolution This class represents a Alluxio path after reverse resolution.
class	MountTable.State Persistent mount table state.

Field Summary

Fields

Modifier and Type	Field and Description
MountTable.State	mState Mount table state that is preserved across restarts.
static String	ROOT

Constructor Summary

Constructors

Constructor and Description
MountTable(UfsManager ufsManager, MountInfo rootMountInfo, java.time.Clock clock) Creates a new instance of MountTable.

Method Summary

Modifier and Type	Method and Description
void	add(java.util.function.Supplier<JournalContext> journalContext, AlluxioURI alluxioUri, AlluxioURI ufsUri, long mountId, MountPOptions options) Mounts the given UFS path at the given Alluxio path.
void	addValidated(java.util.function.Supplier<JournalContext> journalContext, AlluxioURI alluxioUri, AlluxioURI ufsUri, long mountId, MountPOptions options) Inserts an entry into the mount table.
void	checkUnderWritableMountPoint(AlluxioURI alluxioUri) Checks to see if a write operation is allowed for the specified Alluxio path, by determining if it is under a readonly mount point.
boolean	containsMountPoint(AlluxioURI uri, boolean containsSelf)
long	createUnusedMountId() Creates a mount point ID and guarantees uniqueness.
boolean	delete(java.util.function.Supplier<JournalContext> journalContext, AlluxioURI uri, boolean checkNestedMount) Unmounts the given Alluxio path.
List<MountInfo>	findChildrenMountPoints(AlluxioURI uri, boolean containsSelf) Returns the mount points under the specified path.
Journaled	getDelegate()
MountInfo	getMountInfo(AlluxioURI uri) Gets mount information for the path.
MountInfo	getMountInfo(long mountId)
String	getMountPoint(AlluxioURI uri) Returns the closest ancestor mount point the given path is nested under.
Map<String,MountInfo>	getMountTable() Returns a copy of the current mount table, the mount table is a map from Alluxio file system URIs to the corresponding mount point information.
UfsManager.UfsClient	getUfsClient(long mountId) Get the associated ufs client with the mount id.
com.codahale.metrics.Counter	getUfsSyncMetric(long mountId)
UfsSyncPathCache	getUfsSyncPathCache()
Lock	getWriteLock() Returns the underlying write lock of the MountTable.
boolean	isMountPoint(AlluxioURI uri)
MountTable.Resolution	resolve(AlluxioURI uri) Resolves the given Alluxio path.
MountTable.ReverseResolution	reverseResolve(AlluxioURI ufsUri) Resolves the given Ufs path.
void	update(java.util.function.Supplier<JournalContext> journalContext, AlluxioURI alluxioUri, long newMountId, MountPOptions newOptions) Update the mount point with new options and mount ID.
void	validateMountPoint(AlluxioURI alluxioUri, AlluxioURI ufsUri, long mountId, MountPOptions options) Verify if the given (alluxioPath, ufsPath) can be inserted into MountTable.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface alluxio.master.journal.DelegatingJournaled

applyAndJournal, getCheckpointName, getJournalEntryIterator, processJournalEntry, resetState, restoreFromCheckpoint, restoreFromCheckpoint, writeToCheckpoint, writeToCheckpoint

Field Detail

ROOT

public static final String ROOT

See Also:

Constant Field Values

mState

public final MountTable.State mState

Mount table state that is preserved across restarts.

Constructor Detail

MountTable

public MountTable(UfsManager ufsManager,
                  MountInfo rootMountInfo,
                  java.time.Clock clock)

Creates a new instance of MountTable.

Parameters:

ufsManager - the UFS manager

rootMountInfo - root mount info

clock - the clock

Method Detail

getWriteLock

public Lock getWriteLock()

Returns the underlying write lock of the MountTable. This method will be called when fileSystemMaster is adding a new MountPoint.

Returns:

the write lock of the mountTable

add

public void add(java.util.function.Supplier<JournalContext> journalContext,
                AlluxioURI alluxioUri,
                AlluxioURI ufsUri,
                long mountId,
                MountPOptions options)
         throws FileAlreadyExistsException,
                InvalidPathException,
                IOException

Mounts the given UFS path at the given Alluxio path. The Alluxio path should not be nested under an existing mount point.

Parameters:

journalContext - the journal context

alluxioUri - an Alluxio path URI

ufsUri - a UFS path URI

mountId - the mount id

options - the mount options

Throws:

FileAlreadyExistsException - if the mount point already exists

InvalidPathException - if an invalid path is encountered

IOException

addValidated

public void addValidated(java.util.function.Supplier<JournalContext> journalContext,
                         AlluxioURI alluxioUri,
                         AlluxioURI ufsUri,
                         long mountId,
                         MountPOptions options)

Inserts an entry into the mount table. Before calling this method, the caller must hold the write lock to the mount table. The caller must also have validated the mount information to make sure the mount will succeed.

 try (LockResource mountTableLock = new LockResource(mMountTable.getWriteLock()) {
     mMountTable.validateMountPoint(alluxioPath, ufsPath);
     mMountTable.addValidated(alluxioPath, ufsPath);
     ...
  }
 

Parameters:

journalContext - the journal context

alluxioUri - the uri of Alluxio Mount Point

ufsUri - the uri of UFS Path

mountId - the mount id

options - the mount options

validateMountPoint

public void validateMountPoint(AlluxioURI alluxioUri,
                               AlluxioURI ufsUri,
                               long mountId,
                               MountPOptions options)
                        throws FileAlreadyExistsException,
                               InvalidPathException,
                               IOException

Verify if the given (alluxioPath, ufsPath) can be inserted into MountTable. This method is NOT ThreadSafe. This method will not acquire any locks, so the caller MUST apply the lock first before calling this method.

Parameters:

alluxioUri - the alluxio path that is about to be the mount point

ufsUri - the UFS path that is about to mount

mountId - the mount id

options - the mount options

Throws:

FileAlreadyExistsException

InvalidPathException

IOException

getUfsSyncMetric

public com.codahale.metrics.Counter getUfsSyncMetric(long mountId)

Parameters:

mountId - the mount id

Returns:

the ufs sync counter metric for the mount id

delete

public boolean delete(java.util.function.Supplier<JournalContext> journalContext,
                      AlluxioURI uri,
                      boolean checkNestedMount)

Unmounts the given Alluxio path. The path should match an existing mount point.

Parameters:

journalContext - journal context

uri - an Alluxio path URI

checkNestedMount - whether to check nested mount points before delete

Returns:

whether the operation succeeded or not

update

public void update(java.util.function.Supplier<JournalContext> journalContext,
                   AlluxioURI alluxioUri,
                   long newMountId,
                   MountPOptions newOptions)
            throws InvalidPathException,
                   FileAlreadyExistsException,
                   IOException

Update the mount point with new options and mount ID.

Parameters:

journalContext - the journal context

alluxioUri - an Alluxio path URI

newMountId - the mount id

newOptions - the mount options

Throws:

FileAlreadyExistsException - if the mount point already exists

InvalidPathException - if an invalid path is encountered

IOException

getMountPoint

public String getMountPoint(AlluxioURI uri)
                     throws InvalidPathException

Returns the closest ancestor mount point the given path is nested under.

Parameters:

uri - an Alluxio path URI

Returns:

mount point the given Alluxio path is nested under

Throws:

InvalidPathException - if an invalid path is encountered

getMountTable

public Map<String,MountInfo> getMountTable()

Returns a copy of the current mount table, the mount table is a map from Alluxio file system URIs to the corresponding mount point information.

Returns:

a copy of the current mount table

containsMountPoint

public boolean containsMountPoint(AlluxioURI uri,
                                  boolean containsSelf)
                           throws InvalidPathException

Parameters:

uri - the Alluxio uri to check

containsSelf - cause method to return true when given uri itself is a mount point

Returns:

true if the given uri has a descendant which is a mount point [, or is a mount point]

Throws:

InvalidPathException

findChildrenMountPoints

public List<MountInfo> findChildrenMountPoints(AlluxioURI uri,
                                               boolean containsSelf)
                                        throws InvalidPathException

Returns the mount points under the specified path.

Parameters:

uri - the Alluxio uri to check

containsSelf - if the given uri itself can be a mount point and included in the return

Returns:

the mount points found

Throws:

InvalidPathException

isMountPoint

public boolean isMountPoint(AlluxioURI uri)

Parameters:

uri - an Alluxio path URI

Returns:

whether the given uri is a mount point

reverseResolve

@Nullable
public MountTable.ReverseResolution reverseResolve(AlluxioURI ufsUri)

Resolves the given Ufs path. If the given UFs path is mounted in Alluxio space, it returns the associated Alluxio path.

Parameters:

ufsUri - an Ufs path URI

Returns:

an Alluxio path URI

getUfsClient

@Nullable
public UfsManager.UfsClient getUfsClient(long mountId)

Get the associated ufs client with the mount id.

Parameters:

mountId - mount id to look up ufs client

Returns:

ufsClient

resolve

public MountTable.Resolution resolve(AlluxioURI uri)
                              throws InvalidPathException

Resolves the given Alluxio path. If the given Alluxio path is nested under a mount point, the resolution maps the Alluxio path to the corresponding UFS path. Otherwise, the resolution is a no-op.

Parameters:

uri - an Alluxio path URI

Returns:

the MountTable.Resolution representing the UFS path

Throws:

InvalidPathException - if an invalid path is encountered

checkUnderWritableMountPoint

public void checkUnderWritableMountPoint(AlluxioURI alluxioUri)
                                  throws InvalidPathException,
                                         AccessControlException

Checks to see if a write operation is allowed for the specified Alluxio path, by determining if it is under a readonly mount point.

Parameters:

alluxioUri - an Alluxio path URI

Throws:

InvalidPathException - if the Alluxio path is invalid

AccessControlException - if the Alluxio path is under a readonly mount point

getMountInfo

@Nullable
public MountInfo getMountInfo(long mountId)

Parameters:

mountId - the given ufs id

Returns:

the mount information with this id or null if this mount id is not found

getMountInfo

public MountInfo getMountInfo(AlluxioURI uri)
                       throws InvalidPathException

Gets mount information for the path.

Parameters:

uri - the path

Returns:

the mount information

Throws:

InvalidPathException

getUfsSyncPathCache

public UfsSyncPathCache getUfsSyncPathCache()

Returns:

the invalidation sync cache

getDelegate

public Journaled getDelegate()

Specified by:

getDelegate in interface DelegatingJournaled

Returns:

the object to delegate to

createUnusedMountId

public long createUnusedMountId()

Creates a mount point ID and guarantees uniqueness.

Returns:

the mount point ID