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Posted to common-commits@hadoop.apache.org by wa...@apache.org on 2015/09/30 17:42:06 UTC
[06/50] [abbrv] hadoop git commit: Merge commit
'456e901a4c5c639267ee87b8e5f1319f256d20c2' (HDFS-6407. Add sorting and
pagination in the datanode tab of the NN Web UI. Contributed by Haohui Mai.)
into HDFS-7285-merge
http://git-wip-us.apache.org/repos/asf/hadoop/blob/6b6a63bb/hadoop-hdfs-project/hadoop-hdfs-client/src/main/java/org/apache/hadoop/hdfs/protocol/ClientProtocol.java
----------------------------------------------------------------------
diff --cc hadoop-hdfs-project/hadoop-hdfs-client/src/main/java/org/apache/hadoop/hdfs/protocol/ClientProtocol.java
index 0000000,8528999..7756bb9
mode 000000,100644..100644
--- a/hadoop-hdfs-project/hadoop-hdfs-client/src/main/java/org/apache/hadoop/hdfs/protocol/ClientProtocol.java
+++ b/hadoop-hdfs-project/hadoop-hdfs-client/src/main/java/org/apache/hadoop/hdfs/protocol/ClientProtocol.java
@@@ -1,0 -1,1486 +1,1511 @@@
+ /**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements. See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. The ASF licenses this file
+ * to you 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.hadoop.hdfs.protocol;
+
+ import java.io.IOException;
+ import java.util.EnumSet;
+ import java.util.List;
+
+ import org.apache.hadoop.classification.InterfaceAudience;
+ import org.apache.hadoop.classification.InterfaceStability;
+ import org.apache.hadoop.crypto.CryptoProtocolVersion;
+ import org.apache.hadoop.fs.BatchedRemoteIterator.BatchedEntries;
+ import org.apache.hadoop.fs.CacheFlag;
+ import org.apache.hadoop.fs.ContentSummary;
+ import org.apache.hadoop.fs.CreateFlag;
+ import org.apache.hadoop.fs.FsServerDefaults;
+ import org.apache.hadoop.fs.Options;
+ import org.apache.hadoop.fs.StorageType;
+ import org.apache.hadoop.fs.XAttr;
+ import org.apache.hadoop.fs.XAttrSetFlag;
+ import org.apache.hadoop.fs.permission.AclEntry;
+ import org.apache.hadoop.fs.permission.AclStatus;
+ import org.apache.hadoop.fs.permission.FsAction;
+ import org.apache.hadoop.fs.permission.FsPermission;
+ import org.apache.hadoop.hdfs.inotify.EventBatchList;
+ import org.apache.hadoop.hdfs.protocol.HdfsConstants.RollingUpgradeAction;
+ import org.apache.hadoop.hdfs.security.token.block.DataEncryptionKey;
+ import org.apache.hadoop.hdfs.security.token.delegation.DelegationTokenIdentifier;
+ import org.apache.hadoop.hdfs.security.token.delegation.DelegationTokenSelector;
+ import org.apache.hadoop.hdfs.server.protocol.DatanodeStorageReport;
+ import org.apache.hadoop.io.EnumSetWritable;
+ import org.apache.hadoop.io.Text;
+ import org.apache.hadoop.io.retry.AtMostOnce;
+ import org.apache.hadoop.io.retry.Idempotent;
+ import org.apache.hadoop.security.KerberosInfo;
+ import org.apache.hadoop.security.token.Token;
+ import org.apache.hadoop.security.token.TokenInfo;
+
+ import static org.apache.hadoop.hdfs.client.HdfsClientConfigKeys.DFS_NAMENODE_KERBEROS_PRINCIPAL_KEY;
+
+ /**********************************************************************
+ * ClientProtocol is used by user code via the DistributedFileSystem class to
+ * communicate with the NameNode. User code can manipulate the directory
+ * namespace, as well as open/close file streams, etc.
+ *
+ **********************************************************************/
+ @InterfaceAudience.Private
+ @InterfaceStability.Evolving
+ @KerberosInfo(
+ serverPrincipal = DFS_NAMENODE_KERBEROS_PRINCIPAL_KEY)
+ @TokenInfo(DelegationTokenSelector.class)
+ public interface ClientProtocol {
+
+ /**
+ * Until version 69, this class ClientProtocol served as both
+ * the client interface to the NN AND the RPC protocol used to
+ * communicate with the NN.
+ *
+ * This class is used by both the DFSClient and the
+ * NN server side to insulate from the protocol serialization.
+ *
+ * If you are adding/changing this interface then you need to
+ * change both this class and ALSO related protocol buffer
+ * wire protocol definition in ClientNamenodeProtocol.proto.
+ *
+ * For more details on protocol buffer wire protocol, please see
+ * .../org/apache/hadoop/hdfs/protocolPB/overview.html
+ *
+ * The log of historical changes can be retrieved from the svn).
+ * 69: Eliminate overloaded method names.
+ *
+ * 69L is the last version id when this class was used for protocols
+ * serialization. DO not update this version any further.
+ */
+ long versionID = 69L;
+
+ ///////////////////////////////////////
+ // File contents
+ ///////////////////////////////////////
+ /**
+ * Get locations of the blocks of the specified file
+ * within the specified range.
+ * DataNode locations for each block are sorted by
+ * the proximity to the client.
+ * <p>
+ * Return {@link LocatedBlocks} which contains
+ * file length, blocks and their locations.
+ * DataNode locations for each block are sorted by
+ * the distance to the client's address.
+ * <p>
+ * The client will then have to contact
+ * one of the indicated DataNodes to obtain the actual data.
+ *
+ * @param src file name
+ * @param offset range start offset
+ * @param length range length
+ *
+ * @return file length and array of blocks with their locations
+ *
+ * @throws org.apache.hadoop.security.AccessControlException If access is
+ * denied
+ * @throws java.io.FileNotFoundException If file <code>src</code> does not
+ * exist
+ * @throws org.apache.hadoop.fs.UnresolvedLinkException If <code>src</code>
+ * contains a symlink
+ * @throws IOException If an I/O error occurred
+ */
+ @Idempotent
+ LocatedBlocks getBlockLocations(String src, long offset, long length)
+ throws IOException;
+
+ /**
+ * Get server default values for a number of configuration params.
+ * @return a set of server default configuration values
+ * @throws IOException
+ */
+ @Idempotent
+ FsServerDefaults getServerDefaults() throws IOException;
+
+ /**
+ * Create a new file entry in the namespace.
+ * <p>
+ * This will create an empty file specified by the source path.
+ * The path should reflect a full path originated at the root.
+ * The name-node does not have a notion of "current" directory for a client.
+ * <p>
+ * Once created, the file is visible and available for read to other clients.
+ * Although, other clients cannot {@link #delete(String, boolean)}, re-create
+ * or {@link #rename(String, String)} it until the file is completed
+ * or explicitly as a result of lease expiration.
+ * <p>
+ * Blocks have a maximum size. Clients that intend to create
+ * multi-block files must also use
+ * {@link #addBlock}
+ *
+ * @param src path of the file being created.
+ * @param masked masked permission.
+ * @param clientName name of the current client.
+ * @param flag indicates whether the file should be
+ * overwritten if it already exists or create if it does not exist or append.
+ * @param createParent create missing parent directory if true
+ * @param replication block replication factor.
+ * @param blockSize maximum block size.
+ * @param supportedVersions CryptoProtocolVersions supported by the client
+ *
+ * @return the status of the created file, it could be null if the server
+ * doesn't support returning the file status
+ * @throws org.apache.hadoop.security.AccessControlException If access is
+ * denied
+ * @throws AlreadyBeingCreatedException if the path does not exist.
+ * @throws DSQuotaExceededException If file creation violates disk space
+ * quota restriction
+ * @throws org.apache.hadoop.fs.FileAlreadyExistsException If file
+ * <code>src</code> already exists
+ * @throws java.io.FileNotFoundException If parent of <code>src</code> does
+ * not exist and <code>createParent</code> is false
+ * @throws org.apache.hadoop.fs.ParentNotDirectoryException If parent of
+ * <code>src</code> is not a directory.
+ * @throws NSQuotaExceededException If file creation violates name space
+ * quota restriction
+ * @throws org.apache.hadoop.hdfs.server.namenode.SafeModeException create not
+ * allowed in safemode
+ * @throws org.apache.hadoop.fs.UnresolvedLinkException If <code>src</code>
+ * contains a symlink
+ * @throws SnapshotAccessControlException if path is in RO snapshot
+ * @throws IOException If an I/O error occurred
+ *
+ * RuntimeExceptions:
+ * @throws org.apache.hadoop.fs.InvalidPathException Path <code>src</code> is
+ * invalid
+ * <p>
+ * <em>Note that create with {@link CreateFlag#OVERWRITE} is idempotent.</em>
+ */
+ @AtMostOnce
+ HdfsFileStatus create(String src, FsPermission masked,
+ String clientName, EnumSetWritable<CreateFlag> flag,
+ boolean createParent, short replication, long blockSize,
+ CryptoProtocolVersion[] supportedVersions)
+ throws IOException;
+
+ /**
+ * Append to the end of the file.
+ * @param src path of the file being created.
+ * @param clientName name of the current client.
+ * @param flag indicates whether the data is appended to a new block.
+ * @return wrapper with information about the last partial block and file
+ * status if any
+ * @throws org.apache.hadoop.security.AccessControlException if permission to
+ * append file is denied by the system. As usually on the client side the
+ * exception will be wrapped into
+ * {@link org.apache.hadoop.ipc.RemoteException}.
+ * Allows appending to an existing file if the server is
+ * configured with the parameter dfs.support.append set to true, otherwise
+ * throws an IOException.
+ *
+ * @throws org.apache.hadoop.security.AccessControlException If permission to
+ * append to file is denied
+ * @throws java.io.FileNotFoundException If file <code>src</code> is not found
+ * @throws DSQuotaExceededException If append violates disk space quota
+ * restriction
+ * @throws org.apache.hadoop.hdfs.server.namenode.SafeModeException append not
+ * allowed in safemode
+ * @throws org.apache.hadoop.fs.UnresolvedLinkException If <code>src</code>
+ * contains a symlink
+ * @throws SnapshotAccessControlException if path is in RO snapshot
+ * @throws IOException If an I/O error occurred.
+ *
+ * RuntimeExceptions:
+ * @throws UnsupportedOperationException if append is not supported
+ */
+ @AtMostOnce
+ LastBlockWithStatus append(String src, String clientName,
+ EnumSetWritable<CreateFlag> flag) throws IOException;
+
+ /**
+ * Set replication for an existing file.
+ * <p>
+ * The NameNode sets replication to the new value and returns.
+ * The actual block replication is not expected to be performed during
+ * this method call. The blocks will be populated or removed in the
+ * background as the result of the routine block maintenance procedures.
+ *
+ * @param src file name
+ * @param replication new replication
+ *
+ * @return true if successful;
+ * false if file does not exist or is a directory
+ *
+ * @throws org.apache.hadoop.security.AccessControlException If access is
+ * denied
+ * @throws DSQuotaExceededException If replication violates disk space
+ * quota restriction
+ * @throws java.io.FileNotFoundException If file <code>src</code> is not found
+ * @throws org.apache.hadoop.hdfs.server.namenode.SafeModeException not
+ * allowed in safemode
+ * @throws org.apache.hadoop.fs.UnresolvedLinkException if <code>src</code>
+ * contains a symlink
+ * @throws SnapshotAccessControlException if path is in RO snapshot
+ * @throws IOException If an I/O error occurred
+ */
+ @Idempotent
+ boolean setReplication(String src, short replication)
+ throws IOException;
+
+ /**
+ * Get all the available block storage policies.
+ * @return All the in-use block storage policies currently.
+ */
+ @Idempotent
+ BlockStoragePolicy[] getStoragePolicies() throws IOException;
+
+ /**
+ * Set the storage policy for a file/directory.
+ * @param src Path of an existing file/directory.
+ * @param policyName The name of the storage policy
+ * @throws SnapshotAccessControlException If access is denied
+ * @throws org.apache.hadoop.fs.UnresolvedLinkException if <code>src</code>
+ * contains a symlink
+ * @throws java.io.FileNotFoundException If file/dir <code>src</code> is not
+ * found
+ * @throws QuotaExceededException If changes violate the quota restriction
+ */
+ @Idempotent
+ void setStoragePolicy(String src, String policyName)
+ throws IOException;
+
+ /**
+ * Get the storage policy for a file/directory.
+ * @param path
+ * Path of an existing file/directory.
+ * @throws AccessControlException
+ * If access is denied
+ * @throws org.apache.hadoop.fs.UnresolvedLinkException
+ * if <code>src</code> contains a symlink
+ * @throws java.io.FileNotFoundException
+ * If file/dir <code>src</code> is not found
+ */
+ @Idempotent
+ BlockStoragePolicy getStoragePolicy(String path) throws IOException;
+
+ /**
+ * Set permissions for an existing file/directory.
+ *
+ * @throws org.apache.hadoop.security.AccessControlException If access is
+ * denied
+ * @throws java.io.FileNotFoundException If file <code>src</code> is not found
+ * @throws org.apache.hadoop.hdfs.server.namenode.SafeModeException not
+ * allowed in safemode
+ * @throws org.apache.hadoop.fs.UnresolvedLinkException If <code>src</code>
+ * contains a symlink
+ * @throws SnapshotAccessControlException if path is in RO snapshot
+ * @throws IOException If an I/O error occurred
+ */
+ @Idempotent
+ void setPermission(String src, FsPermission permission)
+ throws IOException;
+
+ /**
+ * Set Owner of a path (i.e. a file or a directory).
+ * The parameters username and groupname cannot both be null.
+ * @param src file path
+ * @param username If it is null, the original username remains unchanged.
+ * @param groupname If it is null, the original groupname remains unchanged.
+ *
+ * @throws org.apache.hadoop.security.AccessControlException If access is
+ * denied
+ * @throws java.io.FileNotFoundException If file <code>src</code> is not found
+ * @throws org.apache.hadoop.hdfs.server.namenode.SafeModeException not
+ * allowed in safemode
+ * @throws org.apache.hadoop.fs.UnresolvedLinkException If <code>src</code>
+ * contains a symlink
+ * @throws SnapshotAccessControlException if path is in RO snapshot
+ * @throws IOException If an I/O error occurred
+ */
+ @Idempotent
+ void setOwner(String src, String username, String groupname)
+ throws IOException;
+
+ /**
+ * The client can give up on a block by calling abandonBlock().
+ * The client can then either obtain a new block, or complete or abandon the
+ * file.
+ * Any partial writes to the block will be discarded.
+ *
+ * @param b Block to abandon
+ * @param fileId The id of the file where the block resides. Older clients
+ * will pass GRANDFATHER_INODE_ID here.
+ * @param src The path of the file where the block resides.
+ * @param holder Lease holder.
+ *
+ * @throws org.apache.hadoop.security.AccessControlException If access is
+ * denied
+ * @throws java.io.FileNotFoundException file <code>src</code> is not found
+ * @throws org.apache.hadoop.fs.UnresolvedLinkException If <code>src</code>
+ * contains a symlink
+ * @throws IOException If an I/O error occurred
+ */
+ @Idempotent
+ void abandonBlock(ExtendedBlock b, long fileId,
+ String src, String holder)
+ throws IOException;
+
+ /**
+ * A client that wants to write an additional block to the
+ * indicated filename (which must currently be open for writing)
+ * should call addBlock().
+ *
+ * addBlock() allocates a new block and datanodes the block data
+ * should be replicated to.
+ *
+ * addBlock() also commits the previous block by reporting
+ * to the name-node the actual generation stamp and the length
+ * of the block that the client has transmitted to data-nodes.
+ *
+ * @param src the file being created
+ * @param clientName the name of the client that adds the block
+ * @param previous previous block
+ * @param excludeNodes a list of nodes that should not be
+ * allocated for the current block
+ * @param fileId the id uniquely identifying a file
+ * @param favoredNodes the list of nodes where the client wants the blocks.
+ * Nodes are identified by either host name or address.
+ *
+ * @return LocatedBlock allocated block information.
+ *
+ * @throws org.apache.hadoop.security.AccessControlException If access is
+ * denied
+ * @throws java.io.FileNotFoundException If file <code>src</code> is not found
+ * @throws org.apache.hadoop.hdfs.server.namenode.NotReplicatedYetException
+ * previous blocks of the file are not replicated yet.
+ * Blocks cannot be added until replication completes.
+ * @throws org.apache.hadoop.hdfs.server.namenode.SafeModeException create not
+ * allowed in safemode
+ * @throws org.apache.hadoop.fs.UnresolvedLinkException If <code>src</code>
+ * contains a symlink
+ * @throws IOException If an I/O error occurred
+ */
+ @Idempotent
+ LocatedBlock addBlock(String src, String clientName,
+ ExtendedBlock previous, DatanodeInfo[] excludeNodes, long fileId,
+ String[] favoredNodes)
+ throws IOException;
+
+ /**
+ * Get a datanode for an existing pipeline.
+ *
+ * @param src the file being written
+ * @param fileId the ID of the file being written
+ * @param blk the block being written
+ * @param existings the existing nodes in the pipeline
+ * @param excludes the excluded nodes
+ * @param numAdditionalNodes number of additional datanodes
+ * @param clientName the name of the client
+ *
+ * @return the located block.
+ *
+ * @throws org.apache.hadoop.security.AccessControlException If access is
+ * denied
+ * @throws java.io.FileNotFoundException If file <code>src</code> is not found
+ * @throws org.apache.hadoop.hdfs.server.namenode.SafeModeException create not
+ * allowed in safemode
+ * @throws org.apache.hadoop.fs.UnresolvedLinkException If <code>src</code>
+ * contains a symlink
+ * @throws IOException If an I/O error occurred
+ */
+ @Idempotent
+ LocatedBlock getAdditionalDatanode(final String src,
+ final long fileId, final ExtendedBlock blk,
+ final DatanodeInfo[] existings,
+ final String[] existingStorageIDs,
+ final DatanodeInfo[] excludes,
+ final int numAdditionalNodes, final String clientName
+ ) throws IOException;
+
+ /**
+ * The client is done writing data to the given filename, and would
+ * like to complete it.
+ *
+ * The function returns whether the file has been closed successfully.
+ * If the function returns false, the caller should try again.
+ *
+ * close() also commits the last block of file by reporting
+ * to the name-node the actual generation stamp and the length
+ * of the block that the client has transmitted to data-nodes.
+ *
+ * A call to complete() will not return true until all the file's
+ * blocks have been replicated the minimum number of times. Thus,
+ * DataNode failures may cause a client to call complete() several
+ * times before succeeding.
+ *
+ * @param src the file being created
+ * @param clientName the name of the client that adds the block
+ * @param last the last block info
+ * @param fileId the id uniquely identifying a file
+ *
+ * @return true if all file blocks are minimally replicated or false otherwise
+ *
+ * @throws org.apache.hadoop.security.AccessControlException If access is
+ * denied
+ * @throws java.io.FileNotFoundException If file <code>src</code> is not found
+ * @throws org.apache.hadoop.hdfs.server.namenode.SafeModeException create not
+ * allowed in safemode
+ * @throws org.apache.hadoop.fs.UnresolvedLinkException If <code>src</code>
+ * contains a symlink
+ * @throws IOException If an I/O error occurred
+ */
+ @Idempotent
+ boolean complete(String src, String clientName,
+ ExtendedBlock last, long fileId)
+ throws IOException;
+
+ /**
+ * The client wants to report corrupted blocks (blocks with specified
+ * locations on datanodes).
+ * @param blocks Array of located blocks to report
+ */
+ @Idempotent
+ void reportBadBlocks(LocatedBlock[] blocks) throws IOException;
+
+ ///////////////////////////////////////
+ // Namespace management
+ ///////////////////////////////////////
+ /**
+ * Rename an item in the file system namespace.
+ * @param src existing file or directory name.
+ * @param dst new name.
+ * @return true if successful, or false if the old name does not exist
+ * or if the new name already belongs to the namespace.
+ *
+ * @throws SnapshotAccessControlException if path is in RO snapshot
+ * @throws IOException an I/O error occurred
+ */
+ @AtMostOnce
+ boolean rename(String src, String dst)
+ throws IOException;
+
+ /**
+ * Moves blocks from srcs to trg and delete srcs.
+ *
+ * @param trg existing file
+ * @param srcs - list of existing files (same block size, same replication)
+ * @throws IOException if some arguments are invalid
+ * @throws org.apache.hadoop.fs.UnresolvedLinkException if <code>trg</code> or
+ * <code>srcs</code> contains a symlink
+ * @throws SnapshotAccessControlException if path is in RO snapshot
+ */
+ @AtMostOnce
+ void concat(String trg, String[] srcs)
+ throws IOException;
+
+ /**
+ * Rename src to dst.
+ * <ul>
+ * <li>Fails if src is a file and dst is a directory.
+ * <li>Fails if src is a directory and dst is a file.
+ * <li>Fails if the parent of dst does not exist or is a file.
+ * </ul>
+ * <p>
+ * Without OVERWRITE option, rename fails if the dst already exists.
+ * With OVERWRITE option, rename overwrites the dst, if it is a file
+ * or an empty directory. Rename fails if dst is a non-empty directory.
+ * <p>
+ * This implementation of rename is atomic.
+ * <p>
+ * @param src existing file or directory name.
+ * @param dst new name.
+ * @param options Rename options
+ *
+ * @throws org.apache.hadoop.security.AccessControlException If access is
+ * denied
+ * @throws DSQuotaExceededException If rename violates disk space
+ * quota restriction
+ * @throws org.apache.hadoop.fs.FileAlreadyExistsException If <code>dst</code>
+ * already exists and <code>options</code> has
+ * {@link org.apache.hadoop.fs.Options.Rename#OVERWRITE} option
+ * false.
+ * @throws java.io.FileNotFoundException If <code>src</code> does not exist
+ * @throws NSQuotaExceededException If rename violates namespace
+ * quota restriction
+ * @throws org.apache.hadoop.fs.ParentNotDirectoryException If parent of
+ * <code>dst</code> is not a directory
+ * @throws org.apache.hadoop.hdfs.server.namenode.SafeModeException rename not
+ * allowed in safemode
+ * @throws org.apache.hadoop.fs.UnresolvedLinkException If <code>src</code> or
+ * <code>dst</code> contains a symlink
+ * @throws SnapshotAccessControlException if path is in RO snapshot
+ * @throws IOException If an I/O error occurred
+ */
+ @AtMostOnce
+ void rename2(String src, String dst, Options.Rename... options)
+ throws IOException;
+
+ /**
+ * Truncate file src to new size.
+ * <ul>
+ * <li>Fails if src is a directory.
+ * <li>Fails if src does not exist.
+ * <li>Fails if src is not closed.
+ * <li>Fails if new size is greater than current size.
+ * </ul>
+ * <p>
+ * This implementation of truncate is purely a namespace operation if truncate
+ * occurs at a block boundary. Requires DataNode block recovery otherwise.
+ * <p>
+ * @param src existing file
+ * @param newLength the target size
+ *
+ * @return true if client does not need to wait for block recovery,
+ * false if client needs to wait for block recovery.
+ *
+ * @throws org.apache.hadoop.security.AccessControlException If access is
+ * denied
+ * @throws java.io.FileNotFoundException If file <code>src</code> is not found
+ * @throws org.apache.hadoop.hdfs.server.namenode.SafeModeException truncate
+ * not allowed in safemode
+ * @throws org.apache.hadoop.fs.UnresolvedLinkException If <code>src</code>
+ * contains a symlink
+ * @throws SnapshotAccessControlException if path is in RO snapshot
+ * @throws IOException If an I/O error occurred
+ */
+ @Idempotent
+ boolean truncate(String src, long newLength, String clientName)
+ throws IOException;
+
+ /**
+ * Delete the given file or directory from the file system.
+ * <p>
+ * same as delete but provides a way to avoid accidentally
+ * deleting non empty directories programmatically.
+ * @param src existing name
+ * @param recursive if true deletes a non empty directory recursively,
+ * else throws an exception.
+ * @return true only if the existing file or directory was actually removed
+ * from the file system.
+ *
+ * @throws org.apache.hadoop.security.AccessControlException If access is
+ * denied
+ * @throws java.io.FileNotFoundException If file <code>src</code> is not found
+ * @throws org.apache.hadoop.hdfs.server.namenode.SafeModeException create not
+ * allowed in safemode
+ * @throws org.apache.hadoop.fs.UnresolvedLinkException If <code>src</code>
+ * contains a symlink
+ * @throws SnapshotAccessControlException if path is in RO snapshot
+ * @throws IOException If an I/O error occurred
+ */
+ @AtMostOnce
+ boolean delete(String src, boolean recursive)
+ throws IOException;
+
+ /**
+ * Create a directory (or hierarchy of directories) with the given
+ * name and permission.
+ *
+ * @param src The path of the directory being created
+ * @param masked The masked permission of the directory being created
+ * @param createParent create missing parent directory if true
+ *
+ * @return True if the operation success.
+ *
+ * @throws org.apache.hadoop.security.AccessControlException If access is
+ * denied
+ * @throws org.apache.hadoop.fs.FileAlreadyExistsException If <code>src</code>
+ * already exists
+ * @throws java.io.FileNotFoundException If parent of <code>src</code> does
+ * not exist and <code>createParent</code> is false
+ * @throws NSQuotaExceededException If file creation violates quota
+ * restriction
+ * @throws org.apache.hadoop.fs.ParentNotDirectoryException If parent of
+ * <code>src</code> is not a directory
+ * @throws org.apache.hadoop.hdfs.server.namenode.SafeModeException create not
+ * allowed in safemode
+ * @throws org.apache.hadoop.fs.UnresolvedLinkException If <code>src</code>
+ * contains a symlink
+ * @throws SnapshotAccessControlException if path is in RO snapshot
+ * @throws IOException If an I/O error occurred.
+ *
+ * RunTimeExceptions:
+ * @throws org.apache.hadoop.fs.InvalidPathException If <code>src</code> is
+ * invalid
+ */
+ @Idempotent
+ boolean mkdirs(String src, FsPermission masked, boolean createParent)
+ throws IOException;
+
+ /**
+ * Get a partial listing of the indicated directory.
+ *
+ * @param src the directory name
+ * @param startAfter the name to start listing after encoded in java UTF8
+ * @param needLocation if the FileStatus should contain block locations
+ *
+ * @return a partial listing starting after startAfter
+ *
+ * @throws org.apache.hadoop.security.AccessControlException permission denied
+ * @throws java.io.FileNotFoundException file <code>src</code> is not found
+ * @throws org.apache.hadoop.fs.UnresolvedLinkException If <code>src</code>
+ * contains a symlink
+ * @throws IOException If an I/O error occurred
+ */
+ @Idempotent
+ DirectoryListing getListing(String src, byte[] startAfter,
+ boolean needLocation) throws IOException;
+
+ /**
+ * Get listing of all the snapshottable directories.
+ *
+ * @return Information about all the current snapshottable directory
+ * @throws IOException If an I/O error occurred
+ */
+ @Idempotent
+ SnapshottableDirectoryStatus[] getSnapshottableDirListing()
+ throws IOException;
+
+ ///////////////////////////////////////
+ // System issues and management
+ ///////////////////////////////////////
+
+ /**
+ * Client programs can cause stateful changes in the NameNode
+ * that affect other clients. A client may obtain a file and
+ * neither abandon nor complete it. A client might hold a series
+ * of locks that prevent other clients from proceeding.
+ * Clearly, it would be bad if a client held a bunch of locks
+ * that it never gave up. This can happen easily if the client
+ * dies unexpectedly.
+ * <p>
+ * So, the NameNode will revoke the locks and live file-creates
+ * for clients that it thinks have died. A client tells the
+ * NameNode that it is still alive by periodically calling
+ * renewLease(). If a certain amount of time passes since
+ * the last call to renewLease(), the NameNode assumes the
+ * client has died.
+ *
+ * @throws org.apache.hadoop.security.AccessControlException permission denied
+ * @throws IOException If an I/O error occurred
+ */
+ @Idempotent
+ void renewLease(String clientName) throws IOException;
+
+ /**
+ * Start lease recovery.
+ * Lightweight NameNode operation to trigger lease recovery
+ *
+ * @param src path of the file to start lease recovery
+ * @param clientName name of the current client
+ * @return true if the file is already closed
+ * @throws IOException
+ */
+ @Idempotent
+ boolean recoverLease(String src, String clientName) throws IOException;
+
+ int GET_STATS_CAPACITY_IDX = 0;
+ int GET_STATS_USED_IDX = 1;
+ int GET_STATS_REMAINING_IDX = 2;
+ int GET_STATS_UNDER_REPLICATED_IDX = 3;
+ int GET_STATS_CORRUPT_BLOCKS_IDX = 4;
+ int GET_STATS_MISSING_BLOCKS_IDX = 5;
+ int GET_STATS_MISSING_REPL_ONE_BLOCKS_IDX = 6;
+
+ /**
+ * Get a set of statistics about the filesystem.
+ * Right now, only seven values are returned.
+ * <ul>
+ * <li> [0] contains the total storage capacity of the system, in bytes.</li>
+ * <li> [1] contains the total used space of the system, in bytes.</li>
+ * <li> [2] contains the available storage of the system, in bytes.</li>
+ * <li> [3] contains number of under replicated blocks in the system.</li>
+ * <li> [4] contains number of blocks with a corrupt replica. </li>
+ * <li> [5] contains number of blocks without any good replicas left. </li>
+ * <li> [6] contains number of blocks which have replication factor
+ * 1 and have lost the only replica. </li>
+ * </ul>
+ * Use public constants like {@link #GET_STATS_CAPACITY_IDX} in place of
+ * actual numbers to index into the array.
+ */
+ @Idempotent
+ long[] getStats() throws IOException;
+
+ /**
+ * Get a report on the system's current datanodes.
+ * One DatanodeInfo object is returned for each DataNode.
+ * Return live datanodes if type is LIVE; dead datanodes if type is DEAD;
+ * otherwise all datanodes if type is ALL.
+ */
+ @Idempotent
+ DatanodeInfo[] getDatanodeReport(HdfsConstants.DatanodeReportType type)
+ throws IOException;
+
+ /**
+ * Get a report on the current datanode storages.
+ */
+ @Idempotent
+ DatanodeStorageReport[] getDatanodeStorageReport(
+ HdfsConstants.DatanodeReportType type) throws IOException;
+
+ /**
+ * Get the block size for the given file.
+ * @param filename The name of the file
+ * @return The number of bytes in each block
+ * @throws IOException
+ * @throws org.apache.hadoop.fs.UnresolvedLinkException if the path contains
+ * a symlink.
+ */
+ @Idempotent
+ long getPreferredBlockSize(String filename)
+ throws IOException;
+
+ /**
+ * Enter, leave or get safe mode.
+ * <p>
+ * Safe mode is a name node state when it
+ * <ol><li>does not accept changes to name space (read-only), and</li>
+ * <li>does not replicate or delete blocks.</li></ol>
+ *
+ * <p>
+ * Safe mode is entered automatically at name node startup.
+ * Safe mode can also be entered manually using
+ * {@link #setSafeMode(HdfsConstants.SafeModeAction,boolean)
+ * setSafeMode(SafeModeAction.SAFEMODE_ENTER,false)}.
+ * <p>
+ * At startup the name node accepts data node reports collecting
+ * information about block locations.
+ * In order to leave safe mode it needs to collect a configurable
+ * percentage called threshold of blocks, which satisfy the minimal
+ * replication condition.
+ * The minimal replication condition is that each block must have at least
+ * <tt>dfs.namenode.replication.min</tt> replicas.
+ * When the threshold is reached the name node extends safe mode
+ * for a configurable amount of time
+ * to let the remaining data nodes to check in before it
+ * will start replicating missing blocks.
+ * Then the name node leaves safe mode.
+ * <p>
+ * If safe mode is turned on manually using
+ * {@link #setSafeMode(HdfsConstants.SafeModeAction,boolean)
+ * setSafeMode(SafeModeAction.SAFEMODE_ENTER,false)}
+ * then the name node stays in safe mode until it is manually turned off
+ * using {@link #setSafeMode(HdfsConstants.SafeModeAction,boolean)
+ * setSafeMode(SafeModeAction.SAFEMODE_LEAVE,false)}.
+ * Current state of the name node can be verified using
+ * {@link #setSafeMode(HdfsConstants.SafeModeAction,boolean)
+ * setSafeMode(SafeModeAction.SAFEMODE_GET,false)}
+ * <h4>Configuration parameters:</h4>
+ * <tt>dfs.safemode.threshold.pct</tt> is the threshold parameter.<br>
+ * <tt>dfs.safemode.extension</tt> is the safe mode extension parameter.<br>
+ * <tt>dfs.namenode.replication.min</tt> is the minimal replication parameter.
+ *
+ * <h4>Special cases:</h4>
+ * The name node does not enter safe mode at startup if the threshold is
+ * set to 0 or if the name space is empty.<br>
+ * If the threshold is set to 1 then all blocks need to have at least
+ * minimal replication.<br>
+ * If the threshold value is greater than 1 then the name node will not be
+ * able to turn off safe mode automatically.<br>
+ * Safe mode can always be turned off manually.
+ *
+ * @param action <ul> <li>0 leave safe mode;</li>
+ * <li>1 enter safe mode;</li>
+ * <li>2 get safe mode state.</li></ul>
+ * @param isChecked If true then action will be done only in ActiveNN.
+ *
+ * @return <ul><li>0 if the safe mode is OFF or</li>
+ * <li>1 if the safe mode is ON.</li></ul>
+ *
+ * @throws IOException
+ */
+ @Idempotent
+ boolean setSafeMode(HdfsConstants.SafeModeAction action, boolean isChecked)
+ throws IOException;
+
+ /**
+ * Save namespace image.
+ * <p>
+ * Saves current namespace into storage directories and reset edits log.
+ * Requires superuser privilege and safe mode.
+ *
+ * @param timeWindow NameNode does a checkpoint if the latest checkpoint was
+ * done beyond the given time period (in seconds).
+ * @param txGap NameNode does a checkpoint if the gap between the latest
+ * checkpoint and the latest transaction id is greater this gap.
+ * @return whether an extra checkpoint has been done
+ *
+ * @throws IOException if image creation failed.
+ */
+ @AtMostOnce
+ boolean saveNamespace(long timeWindow, long txGap) throws IOException;
+
+ /**
+ * Roll the edit log.
+ * Requires superuser privileges.
+ *
+ * @throws org.apache.hadoop.security.AccessControlException if the superuser
+ * privilege is violated
+ * @throws IOException if log roll fails
+ * @return the txid of the new segment
+ */
+ @Idempotent
+ long rollEdits() throws IOException;
+
+ /**
+ * Enable/Disable restore failed storage.
+ * <p>
+ * sets flag to enable restore of failed storage replicas
+ *
+ * @throws org.apache.hadoop.security.AccessControlException if the superuser
+ * privilege is violated.
+ */
+ @Idempotent
+ boolean restoreFailedStorage(String arg) throws IOException;
+
+ /**
+ * Tells the namenode to reread the hosts and exclude files.
+ * @throws IOException
+ */
+ @Idempotent
+ void refreshNodes() throws IOException;
+
+ /**
+ * Finalize previous upgrade.
+ * Remove file system state saved during the upgrade.
+ * The upgrade will become irreversible.
+ *
+ * @throws IOException
+ */
+ @Idempotent
+ void finalizeUpgrade() throws IOException;
+
+ /**
+ * Rolling upgrade operations.
+ * @param action either query, prepare or finalize.
+ * @return rolling upgrade information. On query, if no upgrade is in
+ * progress, returns null.
+ */
+ @Idempotent
+ RollingUpgradeInfo rollingUpgrade(RollingUpgradeAction action)
+ throws IOException;
+
+ /**
+ * @return CorruptFileBlocks, containing a list of corrupt files (with
+ * duplicates if there is more than one corrupt block in a file)
+ * and a cookie
+ * @throws IOException
+ *
+ * Each call returns a subset of the corrupt files in the system. To obtain
+ * all corrupt files, call this method repeatedly and each time pass in the
+ * cookie returned from the previous call.
+ */
+ @Idempotent
+ CorruptFileBlocks listCorruptFileBlocks(String path, String cookie)
+ throws IOException;
+
+ /**
+ * Dumps namenode data structures into specified file. If the file
+ * already exists, then append.
+ *
+ * @throws IOException
+ */
+ @Idempotent
+ void metaSave(String filename) throws IOException;
+
+ /**
+ * Tell all datanodes to use a new, non-persistent bandwidth value for
+ * dfs.balance.bandwidthPerSec.
+ *
+ * @param bandwidth Blanacer bandwidth in bytes per second for this datanode.
+ * @throws IOException
+ */
+ @Idempotent
+ void setBalancerBandwidth(long bandwidth) throws IOException;
+
+ /**
+ * Get the file info for a specific file or directory.
+ * @param src The string representation of the path to the file
+ *
+ * @return object containing information regarding the file
+ * or null if file not found
+ * @throws org.apache.hadoop.security.AccessControlException permission denied
+ * @throws java.io.FileNotFoundException file <code>src</code> is not found
+ * @throws org.apache.hadoop.fs.UnresolvedLinkException if the path contains
+ * a symlink.
+ * @throws IOException If an I/O error occurred
+ */
+ @Idempotent
+ HdfsFileStatus getFileInfo(String src) throws IOException;
+
+ /**
+ * Get the close status of a file.
+ * @param src The string representation of the path to the file
+ *
+ * @return return true if file is closed
+ * @throws org.apache.hadoop.security.AccessControlException permission denied
+ * @throws java.io.FileNotFoundException file <code>src</code> is not found
+ * @throws org.apache.hadoop.fs.UnresolvedLinkException if the path contains
+ * a symlink.
+ * @throws IOException If an I/O error occurred
+ */
+ @Idempotent
+ boolean isFileClosed(String src) throws IOException;
+
+ /**
+ * Get the file info for a specific file or directory. If the path
+ * refers to a symlink then the FileStatus of the symlink is returned.
+ * @param src The string representation of the path to the file
+ *
+ * @return object containing information regarding the file
+ * or null if file not found
+ *
+ * @throws org.apache.hadoop.security.AccessControlException permission denied
+ * @throws org.apache.hadoop.fs.UnresolvedLinkException if <code>src</code>
+ * contains a symlink
+ * @throws IOException If an I/O error occurred
+ */
+ @Idempotent
+ HdfsFileStatus getFileLinkInfo(String src) throws IOException;
+
+ /**
+ * Get {@link ContentSummary} rooted at the specified directory.
+ * @param path The string representation of the path
+ *
+ * @throws org.apache.hadoop.security.AccessControlException permission denied
+ * @throws java.io.FileNotFoundException file <code>path</code> is not found
+ * @throws org.apache.hadoop.fs.UnresolvedLinkException if <code>path</code>
+ * contains a symlink.
+ * @throws IOException If an I/O error occurred
+ */
+ @Idempotent
+ ContentSummary getContentSummary(String path) throws IOException;
+
+ /**
+ * Set the quota for a directory.
+ * @param path The string representation of the path to the directory
+ * @param namespaceQuota Limit on the number of names in the tree rooted
+ * at the directory
+ * @param storagespaceQuota Limit on storage space occupied all the files
+ * under this directory.
+ * @param type StorageType that the space quota is intended to be set on.
+ * It may be null when called by traditional space/namespace
+ * quota. When type is is not null, the storagespaceQuota
+ * parameter is for type specified and namespaceQuota must be
+ * {@link HdfsConstants#QUOTA_DONT_SET}.
+ *
+ * <br><br>
+ *
+ * The quota can have three types of values : (1) 0 or more will set
+ * the quota to that value, (2) {@link HdfsConstants#QUOTA_DONT_SET} implies
+ * the quota will not be changed, and (3) {@link HdfsConstants#QUOTA_RESET}
+ * implies the quota will be reset. Any other value is a runtime error.
+ *
+ * @throws org.apache.hadoop.security.AccessControlException permission denied
+ * @throws java.io.FileNotFoundException file <code>path</code> is not found
+ * @throws QuotaExceededException if the directory size
+ * is greater than the given quota
+ * @throws org.apache.hadoop.fs.UnresolvedLinkException if the
+ * <code>path</code> contains a symlink.
+ * @throws SnapshotAccessControlException if path is in RO snapshot
+ * @throws IOException If an I/O error occurred
+ */
+ @Idempotent
+ void setQuota(String path, long namespaceQuota, long storagespaceQuota,
+ StorageType type) throws IOException;
+
+ /**
+ * Write all metadata for this file into persistent storage.
+ * The file must be currently open for writing.
+ * @param src The string representation of the path
+ * @param inodeId The inode ID, or GRANDFATHER_INODE_ID if the client is
+ * too old to support fsync with inode IDs.
+ * @param client The string representation of the client
+ * @param lastBlockLength The length of the last block (under construction)
+ * to be reported to NameNode
+ * @throws org.apache.hadoop.security.AccessControlException permission denied
+ * @throws java.io.FileNotFoundException file <code>src</code> is not found
+ * @throws org.apache.hadoop.fs.UnresolvedLinkException if <code>src</code>
+ * contains a symlink.
+ * @throws IOException If an I/O error occurred
+ */
+ @Idempotent
+ void fsync(String src, long inodeId, String client, long lastBlockLength)
+ throws IOException;
+
+ /**
+ * Sets the modification and access time of the file to the specified time.
+ * @param src The string representation of the path
+ * @param mtime The number of milliseconds since Jan 1, 1970.
+ * Setting mtime to -1 means that modification time should not
+ * be set by this call.
+ * @param atime The number of milliseconds since Jan 1, 1970.
+ * Setting atime to -1 means that access time should not be set
+ * by this call.
+ *
+ * @throws org.apache.hadoop.security.AccessControlException permission denied
+ * @throws java.io.FileNotFoundException file <code>src</code> is not found
+ * @throws org.apache.hadoop.fs.UnresolvedLinkException if <code>src</code>
+ * contains a symlink.
+ * @throws SnapshotAccessControlException if path is in RO snapshot
+ * @throws IOException If an I/O error occurred
+ */
+ @Idempotent
+ void setTimes(String src, long mtime, long atime) throws IOException;
+
+ /**
+ * Create symlink to a file or directory.
+ * @param target The path of the destination that the
+ * link points to.
+ * @param link The path of the link being created.
+ * @param dirPerm permissions to use when creating parent directories
+ * @param createParent - if true then missing parent dirs are created
+ * if false then parent must exist
+ *
+ * @throws org.apache.hadoop.security.AccessControlException permission denied
+ * @throws org.apache.hadoop.fs.FileAlreadyExistsException If file
+ * <code>link</code> already exists
+ * @throws java.io.FileNotFoundException If parent of <code>link</code> does
+ * not exist and <code>createParent</code> is false
+ * @throws org.apache.hadoop.fs.ParentNotDirectoryException If parent of
+ * <code>link</code> is not a directory.
+ * @throws org.apache.hadoop.fs.UnresolvedLinkException if <code>link</code>
+ * contains a symlink.
+ * @throws SnapshotAccessControlException if path is in RO snapshot
+ * @throws IOException If an I/O error occurred
+ */
+ @AtMostOnce
+ void createSymlink(String target, String link, FsPermission dirPerm,
+ boolean createParent) throws IOException;
+
+ /**
+ * Return the target of the given symlink. If there is an intermediate
+ * symlink in the path (ie a symlink leading up to the final path component)
+ * then the given path is returned with this symlink resolved.
+ *
+ * @param path The path with a link that needs resolution.
+ * @return The path after resolving the first symbolic link in the path.
+ * @throws org.apache.hadoop.security.AccessControlException permission denied
+ * @throws java.io.FileNotFoundException If <code>path</code> does not exist
+ * @throws IOException If the given path does not refer to a symlink
+ * or an I/O error occurred
+ */
+ @Idempotent
+ String getLinkTarget(String path) throws IOException;
+
+ /**
+ * Get a new generation stamp together with an access token for
+ * a block under construction
+ *
+ * This method is called only when a client needs to recover a failed
+ * pipeline or set up a pipeline for appending to a block.
+ *
+ * @param block a block
+ * @param clientName the name of the client
+ * @return a located block with a new generation stamp and an access token
+ * @throws IOException if any error occurs
+ */
+ @Idempotent
+ LocatedBlock updateBlockForPipeline(ExtendedBlock block,
+ String clientName) throws IOException;
+
+ /**
+ * Update a pipeline for a block under construction.
+ *
+ * @param clientName the name of the client
+ * @param oldBlock the old block
+ * @param newBlock the new block containing new generation stamp and length
+ * @param newNodes datanodes in the pipeline
+ * @throws IOException if any error occurs
+ */
+ @AtMostOnce
+ void updatePipeline(String clientName, ExtendedBlock oldBlock,
+ ExtendedBlock newBlock, DatanodeID[] newNodes, String[] newStorageIDs)
+ throws IOException;
+
+ /**
+ * Get a valid Delegation Token.
+ *
+ * @param renewer the designated renewer for the token
+ * @return Token<DelegationTokenIdentifier>
+ * @throws IOException
+ */
+ @Idempotent
+ Token<DelegationTokenIdentifier> getDelegationToken(Text renewer)
+ throws IOException;
+
+ /**
+ * Renew an existing delegation token.
+ *
+ * @param token delegation token obtained earlier
+ * @return the new expiration time
+ * @throws IOException
+ */
+ @Idempotent
+ long renewDelegationToken(Token<DelegationTokenIdentifier> token)
+ throws IOException;
+
+ /**
+ * Cancel an existing delegation token.
+ *
+ * @param token delegation token
+ * @throws IOException
+ */
+ @Idempotent
+ void cancelDelegationToken(Token<DelegationTokenIdentifier> token)
+ throws IOException;
+
+ /**
+ * @return encryption key so a client can encrypt data sent via the
+ * DataTransferProtocol to/from DataNodes.
+ * @throws IOException
+ */
+ @Idempotent
+ DataEncryptionKey getDataEncryptionKey() throws IOException;
+
+ /**
+ * Create a snapshot.
+ * @param snapshotRoot the path that is being snapshotted
+ * @param snapshotName name of the snapshot created
+ * @return the snapshot path.
+ * @throws IOException
+ */
+ @AtMostOnce
+ String createSnapshot(String snapshotRoot, String snapshotName)
+ throws IOException;
+
+ /**
+ * Delete a specific snapshot of a snapshottable directory.
+ * @param snapshotRoot The snapshottable directory
+ * @param snapshotName Name of the snapshot for the snapshottable directory
+ * @throws IOException
+ */
+ @AtMostOnce
+ void deleteSnapshot(String snapshotRoot, String snapshotName)
+ throws IOException;
+
+ /**
+ * Rename a snapshot.
+ * @param snapshotRoot the directory path where the snapshot was taken
+ * @param snapshotOldName old name of the snapshot
+ * @param snapshotNewName new name of the snapshot
+ * @throws IOException
+ */
+ @AtMostOnce
+ void renameSnapshot(String snapshotRoot, String snapshotOldName,
+ String snapshotNewName) throws IOException;
+
+ /**
+ * Allow snapshot on a directory.
+ * @param snapshotRoot the directory to be snapped
+ * @throws IOException on error
+ */
+ @Idempotent
+ void allowSnapshot(String snapshotRoot)
+ throws IOException;
+
+ /**
+ * Disallow snapshot on a directory.
+ * @param snapshotRoot the directory to disallow snapshot
+ * @throws IOException on error
+ */
+ @Idempotent
+ void disallowSnapshot(String snapshotRoot)
+ throws IOException;
+
+ /**
+ * Get the difference between two snapshots, or between a snapshot and the
+ * current tree of a directory.
+ *
+ * @param snapshotRoot
+ * full path of the directory where snapshots are taken
+ * @param fromSnapshot
+ * snapshot name of the from point. Null indicates the current
+ * tree
+ * @param toSnapshot
+ * snapshot name of the to point. Null indicates the current
+ * tree.
+ * @return The difference report represented as a {@link SnapshotDiffReport}.
+ * @throws IOException on error
+ */
+ @Idempotent
+ SnapshotDiffReport getSnapshotDiffReport(String snapshotRoot,
+ String fromSnapshot, String toSnapshot) throws IOException;
+
+ /**
+ * Add a CacheDirective to the CacheManager.
+ *
+ * @param directive A CacheDirectiveInfo to be added
+ * @param flags {@link CacheFlag}s to use for this operation.
+ * @return A CacheDirectiveInfo associated with the added directive
+ * @throws IOException if the directive could not be added
+ */
+ @AtMostOnce
+ long addCacheDirective(CacheDirectiveInfo directive,
+ EnumSet<CacheFlag> flags) throws IOException;
+
+ /**
+ * Modify a CacheDirective in the CacheManager.
+ *
+ * @param flags {@link CacheFlag}s to use for this operation.
+ * @throws IOException if the directive could not be modified
+ */
+ @AtMostOnce
+ void modifyCacheDirective(CacheDirectiveInfo directive,
+ EnumSet<CacheFlag> flags) throws IOException;
+
+ /**
+ * Remove a CacheDirectiveInfo from the CacheManager.
+ *
+ * @param id of a CacheDirectiveInfo
+ * @throws IOException if the cache directive could not be removed
+ */
+ @AtMostOnce
+ void removeCacheDirective(long id) throws IOException;
+
+ /**
+ * List the set of cached paths of a cache pool. Incrementally fetches results
+ * from the server.
+ *
+ * @param prevId The last listed entry ID, or -1 if this is the first call to
+ * listCacheDirectives.
+ * @param filter Parameters to use to filter the list results,
+ * or null to display all directives visible to us.
+ * @return A batch of CacheDirectiveEntry objects.
+ */
+ @Idempotent
+ BatchedEntries<CacheDirectiveEntry> listCacheDirectives(
+ long prevId, CacheDirectiveInfo filter) throws IOException;
+
+ /**
+ * Add a new cache pool.
+ *
+ * @param info Description of the new cache pool
+ * @throws IOException If the request could not be completed.
+ */
+ @AtMostOnce
+ void addCachePool(CachePoolInfo info) throws IOException;
+
+ /**
+ * Modify an existing cache pool.
+ *
+ * @param req
+ * The request to modify a cache pool.
+ * @throws IOException
+ * If the request could not be completed.
+ */
+ @AtMostOnce
+ void modifyCachePool(CachePoolInfo req) throws IOException;
+
+ /**
+ * Remove a cache pool.
+ *
+ * @param pool name of the cache pool to remove.
+ * @throws IOException if the cache pool did not exist, or could not be
+ * removed.
+ */
+ @AtMostOnce
+ void removeCachePool(String pool) throws IOException;
+
+ /**
+ * List the set of cache pools. Incrementally fetches results from the server.
+ *
+ * @param prevPool name of the last pool listed, or the empty string if this
+ * is the first invocation of listCachePools
+ * @return A batch of CachePoolEntry objects.
+ */
+ @Idempotent
+ BatchedEntries<CachePoolEntry> listCachePools(String prevPool)
+ throws IOException;
+
+ /**
+ * Modifies ACL entries of files and directories. This method can add new ACL
+ * entries or modify the permissions on existing ACL entries. All existing
+ * ACL entries that are not specified in this call are retained without
+ * changes. (Modifications are merged into the current ACL.)
+ */
+ @Idempotent
+ void modifyAclEntries(String src, List<AclEntry> aclSpec)
+ throws IOException;
+
+ /**
+ * Removes ACL entries from files and directories. Other ACL entries are
+ * retained.
+ */
+ @Idempotent
+ void removeAclEntries(String src, List<AclEntry> aclSpec)
+ throws IOException;
+
+ /**
+ * Removes all default ACL entries from files and directories.
+ */
+ @Idempotent
+ void removeDefaultAcl(String src) throws IOException;
+
+ /**
+ * Removes all but the base ACL entries of files and directories. The entries
+ * for user, group, and others are retained for compatibility with permission
+ * bits.
+ */
+ @Idempotent
+ void removeAcl(String src) throws IOException;
+
+ /**
+ * Fully replaces ACL of files and directories, discarding all existing
+ * entries.
+ */
+ @Idempotent
+ void setAcl(String src, List<AclEntry> aclSpec) throws IOException;
+
+ /**
+ * Gets the ACLs of files and directories.
+ */
+ @Idempotent
+ AclStatus getAclStatus(String src) throws IOException;
+
+ /**
+ * Create an encryption zone.
+ */
+ @AtMostOnce
+ void createEncryptionZone(String src, String keyName)
+ throws IOException;
+
+ /**
+ * Get the encryption zone for a path.
+ */
+ @Idempotent
+ EncryptionZone getEZForPath(String src)
+ throws IOException;
+
+ /**
+ * Used to implement cursor-based batched listing of {@EncryptionZone}s.
+ *
+ * @param prevId ID of the last item in the previous batch. If there is no
+ * previous batch, a negative value can be used.
+ * @return Batch of encryption zones.
+ */
+ @Idempotent
+ BatchedEntries<EncryptionZone> listEncryptionZones(
+ long prevId) throws IOException;
+
+ /**
+ * Set xattr of a file or directory.
+ * The name must be prefixed with the namespace followed by ".". For example,
+ * "user.attr".
+ * <p/>
+ * Refer to the HDFS extended attributes user documentation for details.
+ *
+ * @param src file or directory
+ * @param xAttr <code>XAttr</code> to set
+ * @param flag set flag
+ * @throws IOException
+ */
+ @AtMostOnce
+ void setXAttr(String src, XAttr xAttr, EnumSet<XAttrSetFlag> flag)
+ throws IOException;
+
+ /**
+ * Get xattrs of a file or directory. Values in xAttrs parameter are ignored.
+ * If xAttrs is null or empty, this is the same as getting all xattrs of the
+ * file or directory. Only those xattrs for which the logged-in user has
+ * permissions to view are returned.
+ * <p/>
+ * Refer to the HDFS extended attributes user documentation for details.
+ *
+ * @param src file or directory
+ * @param xAttrs xAttrs to get
+ * @return List<XAttr> <code>XAttr</code> list
+ * @throws IOException
+ */
+ @Idempotent
+ List<XAttr> getXAttrs(String src, List<XAttr> xAttrs)
+ throws IOException;
+
+ /**
+ * List the xattrs names for a file or directory.
+ * Only the xattr names for which the logged in user has the permissions to
+ * access will be returned.
+ * <p/>
+ * Refer to the HDFS extended attributes user documentation for details.
+ *
+ * @param src file or directory
+ * @return List<XAttr> <code>XAttr</code> list
+ * @throws IOException
+ */
+ @Idempotent
+ List<XAttr> listXAttrs(String src)
+ throws IOException;
+
+ /**
+ * Remove xattr of a file or directory.Value in xAttr parameter is ignored.
+ * The name must be prefixed with the namespace followed by ".". For example,
+ * "user.attr".
+ * <p/>
+ * Refer to the HDFS extended attributes user documentation for details.
+ *
+ * @param src file or directory
+ * @param xAttr <code>XAttr</code> to remove
+ * @throws IOException
+ */
+ @AtMostOnce
+ void removeXAttr(String src, XAttr xAttr) throws IOException;
+
+ /**
+ * Checks if the user can access a path. The mode specifies which access
+ * checks to perform. If the requested permissions are granted, then the
+ * method returns normally. If access is denied, then the method throws an
+ * {@link org.apache.hadoop.security.AccessControlException}.
+ * In general, applications should avoid using this method, due to the risk of
+ * time-of-check/time-of-use race conditions. The permissions on a file may
+ * change immediately after the access call returns.
+ *
+ * @param path Path to check
+ * @param mode type of access to check
+ * @throws org.apache.hadoop.security.AccessControlException if access is
+ * denied
+ * @throws java.io.FileNotFoundException if the path does not exist
+ * @throws IOException see specific implementation
+ */
+ @Idempotent
+ void checkAccess(String path, FsAction mode) throws IOException;
+
+ /**
+ * Get the highest txid the NameNode knows has been written to the edit
+ * log, or -1 if the NameNode's edit log is not yet open for write. Used as
+ * the starting point for the inotify event stream.
+ */
+ @Idempotent
+ long getCurrentEditLogTxid() throws IOException;
+
+ /**
+ * Get an ordered list of batches of events corresponding to the edit log
+ * transactions for txids equal to or greater than txid.
+ */
+ @Idempotent
+ EventBatchList getEditsFromTxid(long txid) throws IOException;
++
++ /**
++ * Create an erasure coding zone with specified policy, if any, otherwise
++ * default
++ */
++ @AtMostOnce
++ void createErasureCodingZone(String src, ErasureCodingPolicy ecPolicy)
++ throws IOException;
++
++ /**
++ * Get the erasure coding policies loaded in Namenode
++ *
++ * @throws IOException
++ */
++ @Idempotent
++ ErasureCodingPolicy[] getErasureCodingPolicies() throws IOException;
++
++ /**
++ * Get the information about the EC zone for the path
++ *
++ * @param src path to get the info for
++ * @throws IOException
++ */
++ @Idempotent
++ ErasureCodingZone getErasureCodingZone(String src) throws IOException;
+ }
http://git-wip-us.apache.org/repos/asf/hadoop/blob/6b6a63bb/hadoop-hdfs-project/hadoop-hdfs-client/src/main/java/org/apache/hadoop/hdfs/protocol/ErasureCodingZone.java
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diff --cc hadoop-hdfs-project/hadoop-hdfs-client/src/main/java/org/apache/hadoop/hdfs/protocol/ErasureCodingZone.java
index 0000000,0000000..533b630
new file mode 100644
--- /dev/null
+++ b/hadoop-hdfs-project/hadoop-hdfs-client/src/main/java/org/apache/hadoop/hdfs/protocol/ErasureCodingZone.java
@@@ -1,0 -1,0 +1,54 @@@
++/**
++ * Licensed to the Apache Software Foundation (ASF) under one or more
++ * contributor license agreements. See the NOTICE file distributed with this
++ * work for additional information regarding copyright ownership. The ASF
++ * licenses this file to you 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.hadoop.hdfs.protocol;
++
++/**
++ * Information about the EC Zone at the specified path.
++ */
++public class ErasureCodingZone {
++
++ private String dir;
++ private ErasureCodingPolicy ecPolicy;
++
++ public ErasureCodingZone(String dir, ErasureCodingPolicy ecPolicy) {
++ this.dir = dir;
++ this.ecPolicy = ecPolicy;
++ }
++
++ /**
++ * Get directory of the EC zone.
++ *
++ * @return
++ */
++ public String getDir() {
++ return dir;
++ }
++
++ /**
++ * Get the erasure coding policy for the EC Zone
++ *
++ * @return
++ */
++ public ErasureCodingPolicy getErasureCodingPolicy() {
++ return ecPolicy;
++ }
++
++ @Override
++ public String toString() {
++ return "Dir: " + getDir() + ", Policy: " + ecPolicy;
++ }
++}
http://git-wip-us.apache.org/repos/asf/hadoop/blob/6b6a63bb/hadoop-hdfs-project/hadoop-hdfs-client/src/main/java/org/apache/hadoop/hdfs/protocol/HdfsConstants.java
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http://git-wip-us.apache.org/repos/asf/hadoop/blob/6b6a63bb/hadoop-hdfs-project/hadoop-hdfs-client/src/main/java/org/apache/hadoop/hdfs/web/JsonUtilClient.java
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