hadoop/hdfs/CHANGES.txt

Hadoop HDFS Change Log

Release 0.22.0 - Unreleased

  INCOMPATIBLE CHANGES

    HDFS-1825. Remove thriftfs contrib. (nigel via eli)

  NEW FEATURES

    HDFS-1921. saveNamespace can cause NN to be unable to come up on restart.
    (Matt Foley)

    HDFS-992. Re-factor block access token implementation to conform to the 
    generic Token interface in Common (Kan Zhang and Jitendra Pandey via 
    jghoman)

    HDFS-599. Allow NameNode to have a seprate port for service requests from
    client requests. (Dmytro Molkov via hairong)

    HDFS-1004. Update NN to support Kerberized SSL from HADOOP-6584. 
    (jghoman and Kan Zhang via jghoman)

    HDFS-1005. Fsck security. (borya and Kan Zhang via jghoman)

    HDFS-1006. getImage/putImage http requests should be https for the case 
    of security enabled. (borya and jghoman via jghoman)

    HDFS-1033. In secure clusters, NN and SNN should verify that the remote 
    principal during image and edits transfer. (jghoman)

    HDFS-1023. Allow http server to start as regular principal if https 
    principal not defined. (jghoman)

    HDFS-1150. Verify datanodes' identities to clients in secure clusters.
    (jghoman)

    HDFS-1330. Make RPCs to DataNodes timeout. (hairong)

    HDFS-202.  HDFS support of listLocatedStatus introduced in HADOOP-6870.
    HDFS piggyback block locations to each file status when listing a
    directory.  (hairong)

    HDFS-1361. Add -fileStatus operation to NNThroughputBenchmark. (shv)

    HDFS-1435. Provide an option to store fsimage compressed. (hairong)

    HDFS-903.  Support fsimage validation through MD5 checksum. (hairong)

    HDFS-1457. Provide an option to throttle image transmission between
    pimary and secondary NameNodes. (Yifei Lu and hairong via hairong)

    HDFS-1164. TestHdfsProxy is failing. (Todd Lipcon via cos)

    HDFS-811. Add metrics, failure reporting and additional tests for HDFS-457.
    (eli)

    HDFS-895. Allow hflush/sync to occur in parallel with new writes
    to the file. (Todd Lipcon via hairong)

    HDFS-528. Add ability for safemode to wait for a minimum number of 
    live datanodes (Todd Lipcon via eli)

    HDFS-1850. DN should transmit absolute failed volume count rather than
    increments to the NN. (eli)

    HDFS-671. Documentation change for updated configuration keys.
    (tomwhite via eli)

  IMPROVEMENTS

    HDFS-1304. Add a new unit test for HftpFileSystem.open(..).  (szetszwo)

    HDFS-1096. fix for prev. commit. (boryas)

    HDFS-1096. allow dfsadmin/mradmin refresh of superuser proxy group
     mappings (boryas)

    HDFS-1146. Javadoc for getDelegationTokenSecretManager in FSNamesystem (jnp via boryas)

    HDFS-1132. Refactor TestFileStatus (Eli Collins via cos)

    HDFS-1163. normalize property names for JT/NN kerberos principal 
    names in configuration (from HADOOP 6633) (boryas)

    HDFS-1003. authorization checks for inter-server protocol 
    (based on HADOOP-6600) (boryas)

    HDFS-1061. Memory footprint optimization for INodeFile object. 
    (Bharath Mundlapudi via jghoman)

    HDFS-1079. Throw exceptions as specified by the AbstractFileSystem
    in HDFS implemenation and protocols. (suresh)

    HDFS-1112. Edit log buffer should not grow unfoundedly. (hairong)

    HDFS-1119. Introduce a GSet interface to BlocksMap.  (szetszwo)

    HDFS-1184. Replace tabs in code with spaces. (Jeff Ames via jghoman)

    HDFS-1185. Remove duplicate now() functions in DataNode, FSNamesysetm.
    (Jeff Ames via jghoman)

    HDFS-1183. Remove some duplicate code in NamenodeJspHelper.java.
    (Jeff Ames via jghoman)
    
    HDFS-1190.  Remove unused getNamenode() method from DataNode.
    (Jeff Ames via jghoman)

    HDFS-1110. Reuses objects for commonly used file names in namenode to
    reduce the heap usage. (suresh)

    HDFS-752. Add interfaces classification to to HDFS source code. (suresh)

    HDFS-947. An Hftp read request is redirected to a datanode that has 
    the most replicas of the blocks in the file. (Dmytro Molkov via dhruba)

    HDFS-1272. Fixes to take care of the changes in HADOOP-6845.
    (Jitendra Pandey via ddas)

    HDFS-1298 - Add support in HDFS for new statistics added in FileSystem
    to track the file system operations. (suresh)

    HDFS-1201. The HDFS component for HADOOP-6632. 
    (Kan Zhang & Jitendra Pandey via ddas)
    
    HDFS-1307 Add start time, end time and total time taken for FSCK to 
    FSCK report (suresh)

    HDFS-1302. The HDFS side of the changes corresponding to HADOOP-6861.
    (Jitendra Pandey & Owen O'Malley via ddas)
    
    HDFS-1315. Add fsck event to audit log and remove other audit log events 
    corresponding to FSCK listStatus and open calls. (suresh)

    HDFS-1178. The NameNode servlets should not use RPC to connect to the 
    NameNode. (Kan Zhang via jghoman)

    HDFS-1130. Adds dfs.cluster.administrator ACL configuration that can
    be used to control who can view the default hdfs servlets. (ddas)

    HDFS-1297. Fix some comments. (Jeff Ames via jghoman)

    HDFS-330.  Datanode Web UIs should provide robots.txt.
    (Allen Wittenauer via jghoman)

    HDFS-881.  Refactor DataNode Packet header into DataTransferProtocol.
    (Todd Lipcon via jghoman)

    HDFS-1036. docs for fetchdt

    HDFS-1318. Add JMX interface for read access to namenode and datanode
    web UI information. (Tanping Wang via suresh).

    HDFS-1356.  Provide information as to whether or not security is 
    enabled on web interface for NameNode (boryas)

    HDFS-1205. FSDatasetAsyncDiskService should name its threads.
    (Todd Lipcon via eli)

    HDFS-1111. Introduce getCorruptFileBlocks() for fsck. (Sriram Rao via shv)

    HDFS-1395. Add @Override to FSDataset methods that implement
    FSDatasetInterface methods. (suresh)

    HDFS-1383. Improve the error messages when using hftp://.  (szetszwo)

    HDFS-1093. Change the FSNamesystem lock to a read/write lock. (dhruba)

    HDFS-1407. Change DataTransferProtocol methods to use Block instead 
    of individual elements of Block. (suresh)

    HDFS-1417. Add @Override to SimulatedFSDataset methods that implement
    FSDatasetInterface methods. (suresh)

    HDFS-1426. Remove unused method BlockInfo#listCount. (hairong)

    HDFS-1456. Provide builder for constructing instances of MiniDFSCluster.
    (jghoman)

    HDFS-1472. Allow programmatic access to fsck output.
    (Ramkumar Vadali via dhruba)

    HADOOP-7007. Update the hudson-test-patch ant target to work with the
    latest test-patch.sh script (gkesavan)

    HDFS-1462. Refactor edit log loading to a separate class from edit log writing.
    (Todd Lipcon via eli)

    HDFS-1485. Fix typo in BlockPlacementPolicy. (Jingguo Yao via shv)

    HDFS-1035. Generate Eclipse's .classpath file from Ivy config. (nigel)

    HDFS-1408. Herriot NN and DN clients should vend statistics. (cos)

    HDFS-1491  Update Hdfs to match the change of methods from protected to public
    in AbstractFileSystem (Hadoop-6903) (sanjay)

    HDFS-1160. Improve some FSDataset warnings and comments. (eli)

    HDFS-556. Provide info on failed volumes in the web ui. (eli)

    HDFS-697. Enable asserts for tests by default. (eli)

    HDFS-1187. Modify fetchdt to allow renewing and canceling token.
    (Owen O'Malley and Kan Zhang via jghoman)

    HDFS-1387. Update HDFS permissions guide for security. (Todd Lipcon via eli)

    HDFS-455. Make NN and DN handle in a intuitive way comma-separated 
    configuration strings. (Michele Catasta via eli)

    HDFS-1071. savenamespace should write the fsimage to all configured 
    fs.name.dir in parallel (Dmytro Molkov via jghoman)
 
    HDFS-1055. Improve thread naming for DataXceivers. 
    (Todd Lipcon and Ramkumar Vadali via eli).

    HDFS-718. Configuration parameter to prevent accidental formatting of 
    HDFS filesystem. (Andrew Ryan via jghoman)

    HDFS-1500. TestOfflineImageViewer failing on trunk. (Todd Lipcon
    via hairong)

    HDFS-1483. DFSClient.getBlockLocations should indicate if corresponding
    blocks are corrupt. (Patrick Kling via hairong)

    HDFS-259. Remove intentionally corrupt 0.13 directory layout creation.
    (Todd Lipcon via eli)

    HDFS-1513. Fix a number of warnings. (eli)

    HDFS-1473. Refactor storage management into separate classes than fsimage
    file reading/writing. (Todd Lipcon via eli)

    HDFS-1582. Remove auto-generated native build files. (rvs via eli)

    HDFS-1861. Rename dfs.datanode.max.xcievers and bump its default value.
    (eli)

    HDFS-1562. Add rack policy tests. (eli)

    HDFS-1866. Document dfs.datanode.max.transfer.threads in hdfs-default.xml
    (Harsh J Chouraria via todd)

    HDFS-1946. HDFS part of HADOOP-7291. (eli)

    HDFS-1947. DFSClient should use mapreduce.task.attempt.id. (eli)

    HDFS-1957. Add documentation for HFTP. (Ari Rabkin via todd)

    HDFS-1454. Update the documentation to reflect that clients don't write
    blocks to local disk before copying to HDFS. (Harsh J Chouraria via todd)

    HDFS-1980. Move build/webapps deeper in the build directory heirarchy
    to aid eclipse users. (todd)

    HDFS-1619. Remove AC_TYPE* from the libhdfs. (Roman Shaposhnik via eli)

    HDFS-1948  Forward port 'hdfs-1520 lightweight namenode operation to
    trigger lease reccovery' (stack)

    HDFS-1954. Improved corrupt files warning on NameNode web UI.
    (Patrick Hunt via shv)

    HDFS-1409. BackupNode registration throwing  
    UnsupportedActionException("register") instead of "journal".
    (Ching-Shen Chen via shv)

    HADOOP-7106. Reorganize project SVN layout to "unsplit" the projects.
    (todd, nigel)

    HDFS-2054  BlockSender.sendChunk() prints ERROR for connection closures
    encountered during transferToFully() (Kihwal Lee via stack)


  OPTIMIZATIONS

    HDFS-1140. Speedup INode.getPathComponents. (Dmytro Molkov via shv)

    HDFS-1081. Performance regression in 
    DistributedFileSystem::getFileBlockLocations in secure systems (jghoman)

    HDFS-1114. Implement LightWeightGSet for BlocksMap in order to reduce
    NameNode memory footprint.  (szetszwo)

    HDFS-1320. Add LOG.isDebugEnabled() guard for each LOG.debug(..).
    (Erik Steffl via szetszwo)

    HDFS-1368. Add a block counter to DatanodeDescriptor. (hairong)

    HDFS-1434. Refactor Datanode#startDataNode method into smaller methods.
    (suresh)

    HDFS-1602. Fix HADOOP-4885 for it is doesn't work as expected. (boryas)

    HDFS-941. The DFS client should cache and reuse open sockets to datanodes
    while performing reads. (bc Wong and Todd Lipcon via todd)

  BUG FIXES

    HDFS-1039. Adding test for  JspHelper.getUGI(jnp via boryas)

    HDFS-1019. Incorrect default values for delegation tokens in 
    hdfs-default.xml (jnp via boryas)

    HDFS-1039.  Service should be set in the token in JspHelper.getUGI(jnp via boryas)

    HDFS-1038. FIX. A test missed in a previous commit for this JIRA. (boryas)

    HDFS-1038. In nn_browsedfscontent.jsp fetch delegation token only 
    if security is enabled. (jnp via boryas)

    HDFS-1044. Cannot submit mapreduce job from secure client to 
    unsecure sever (boryas)

    HDFS-1021. specify correct server principal for RefreshAuthorizationPolicyProtocol 
    and RefreshUserToGroupMappingsProtocol protocols in DFSAdmin (for HADOOP-6612) (boryas)

    HDFS-970. fsync fsimage to disk before closing fsimage file.
    (Todd Lipcon via dhruba)

    HDFS-1027. Update copyright year to 2010. (Ravi Phulari via jghoman)

    HDFS-1080. SecondaryNameNode image transfer should use the defined http 
    address rather than local ip address. (jghoman)

    HDFS-1198. Resolving cross-realm principals. (Jitendra Pandey via jghoman)

    HDFS-1118. Fix socketleak on DFSClient. (Zheng Shao via dhruba)

    HDFS-1192. refreshSuperUserGroupsConfiguration should use server side 
    configuration for the refresh (for HADOOP-6815) (boryas)

    HDFS-1036. in DelegationTokenFetch dfs.getURI returns no port (boryas)

    HDFS-1017. browsedfs jsp should call JspHelper.getUGI rather 
    than using createRemoteUser() (jnp via boryas)

    HDFS-1250. Namenode should reject block reports and block received
    requests from dead datanodes (suresh)

    HDFS-1145. When NameNode is shutdown it does not try to exit
    safemode anymore. (dhruba)

    HDFS-1202. DataBlockScanner throws NPE when updated before 
    initialized. (Todd Lipcon via dhruba)

    HDFS-882. Datanode logs the hostname and port its listening on.
    (Steve Loughran via dhruba)

    HDFS-1238. ant eclipse-files has drifted again, (jghoman)

    HDFS-1045. In secure clusters, re-login is necessary for https 
    clients before opening connections. (jghoman)

    HDFS-1289. Datanode secure mode is broken. (Kan Zhang via jghoman)

    HDFS-1007. HFTP needs to be updated to use delegation tokens (boryas)

    HDFS-1085. HFTP read may fail silently on the client side if there is an
    exception on the server side.  (szetszwo)

    HDFS-1308. job conf key for the services name of DelegationToken for HFTP
    url is constructed incorrectly in HFTPFileSystem (boryas)

    HDFS-1319. Fix location of re-login for secondary namenode from HDFS-999. 
    (jghoman)

    HDFS-1317. Remove the FILEPATH_PATTERN from hdfsproxy.AuthorizationFilter.
    (Rohini Palaniswamy via szetszwo)

    HDFS-912. sed in build.xml on Solaris fails. (Allen Wittenauer via jghoman)

    HDFS-1296. using delegation token over hftp for long running 
    clients (boryas)

    HDFS-1334. open in HftpFileSystem does not add delegation tokens to the url.
    (Jitendra Pandey via jghoman)

    HDFS-1301.  TestHDFSProxy need to use server side conf for ProxyUser 
    stuff. (boryas)

    HDFS-1340. When security is turned off, there is a potential XSS attack. 
    This patch fixes it by removing delegationtoken string from the URL, 
    before returning a response to the client. (Jitendra Pandey via ddas)

    HDFS-1347.  TestDelegationToken uses mortbay.log for logging (boryas)

    HDFS-1157. Modifications introduced by HDFS-1150 are breaking aspect's
    bindings (cos)

    HDFS-1349. Remove empty java files. (Eli Collins)

    HDFS-1340. A null delegation token is appended to the url if security
    is disabled when browsing filesystem. (boryas)
    
    HDFS-1352. Fix jsvc.location. (Eli Collins via jghoman)

    HDFS-1284. TestBlockToken fails.  (Kan Zhang via jghoman)

    HDFS-1355. ant veryclean (clean-cache) doesn't clean enough. 
    (Luke Lu via jghoman)

    HDFS-1353. Remove most of getBlockLocation optimization. (jghoman)

    HDFS-1369. Invalid javadoc reference in FSDatasetMBean.java (Eli Collins)

    HDFS-829. hdfsJniHelper.c: #include <error.h> is not portable. 
    (Allen Wittenauer via jghoman)

    HDFS-1310. The ClientDatanodeProtocol proxy should be stopped in
    DFSInputStream.readBlockLength(..).  (sam rash via szetszwo)

    HDFS-1357. HFTP traffic served by DataNode shouldn't use service port 
    on NameNode. (Kan Zhang via jghoman)

    HDFS-96. HDFS supports blocks larger than 2 GB.
    (Patrick Kling via dhruba)

    HDFS-1433. Fix test failures - TestPread and TestFileLimit. (suresh)

    HDFS-1364. Makes long running HFTP-based applications do relogins
    if necessary. (Jitendra Pandey via ddas)

    HDFS-1399. Distinct minicluster services (e.g. NN and JT) overwrite each
    other's service policies.  (Aaron T. Myers via tomwhite)

    HDFS-1440. Fix TestComputeInvalidateWork failure. (suresh)
 
    HDFS-1498. FSDirectory#unprotectedConcat calls setModificationTime 
    on a file. (eli)

    HDFS-1466. TestFcHdfsSymlink relies on /tmp/test not existing. (eli)

    HDFS-874. TestHDFSFileContextMainOperations fails on weirdly 
    configured DNS hosts. (Todd Lipcon via eli)

    HDFS-1507. TestAbandonBlock should abandon a block. (eli)

    HDFS-1487. FSDirectory.removeBlock() should update diskspace count 
    of the block owner node (Zhong Wang via eli).

    HDFS-1001. DataXceiver and BlockReader disagree on when to send/recv
    CHECKSUM_OK. (bc Wong via eli)

    HDFS-1167. New property for local conf directory in system-test-hdfs.xml
    file. (Vinay Thota via cos)

    HDFS-1467. Append pipeline never succeeds with more than one replica.
    (Todd Lipcon via eli)

    HDFS-1503. TestSaveNamespace fails. (Todd Lipcon via cos)

    HDFS-1524. Image loader should make sure to read every byte in image file.
    (hairong)

    HDFS-1523. TestLargeBlock is failing on trunk. (cos)

    HDFS-1502. TestBlockRecovery triggers NPE in assert. (hairong via cos)

    HDFS-1532. Exclude Findbugs warning in FSImageFormat$Saver. (Todd Lipcon
    via cos)

    HDFS-1527. SocketOutputStream.transferToFully fails for blocks >= 2GB on
    32 bit JVM. (Patrick Kling via cos)

    HDFS-1531. Clean up stack traces due to duplicate MXBean registration.
    (Todd Lipcon via cos)

    HDFS-613. TestBalancer and TestBlockTokenWithDFS fail Balancer assert.
    (Todd Lipcon via cos)

    HDFS-1511. 98 Release Audit warnings on trunk and branch-0.22.
    (jghoman)

    HDFS-1560. dfs.data.dir permissions should default to 700. 
    (Todd Lipcon via eli)

    HDFS-1550. NPE when listing a file with no location. (hairong)

    HDFS-1542. Add test for HADOOP-7082, a deadlock writing Configuration to
    HDFS. (todd)

    HDFS-1504. FSImageSaver should catch all exceptions, not just IOE. (todd)

    HDFS-884. DataNode throws IOException if all data directories are 
    unavailable. (Steve Loughran and shv)

    HDFS-1572. Checkpointer should trigger checkpoint with specified period.
    (jghoman)

    HDFS-1561. BackupNode listens on the default host. (shv)

    HDFS-1591. HDFS part of HADOOP-6642. (Chris Douglas, Po Cheung via shv)

    HDFS-900. Corrupt replicas are not processed correctly in block report (shv)

    HDFS-1529. Incorrect handling of interrupts in waitForAckedSeqno can cause
    deadlock (todd)

    HDFS-1597. Batched edit log syncs can reset synctxid and throw assertions
    (todd)

    HDFS-1618. configure files that are generated as part of the released
    tarball need to have executable bit set (Roman Shaposhnik via cos)

    HDFS-981. test-contrib fails due to test-cactus failure (cos)

    HDFS-1625. Ignore disk space values in TestDataNodeMXBean.  (szetszwo)

    HDFS-1781. Fix the path for jsvc in bin/hdfs.  (John George via szetszwo)

    HDFS-1782. Fix an NPE in FSNamesystem.startFileInternal(..).
    (John George via szetszwo)

    HDFS-1821. Fix username resolution in NameNode.createSymlink(..) and
    FSDirectory.addSymlink(..).  (John George via szetszwo)

    HDFS-1806. TestBlockReport.blockReport_08() and _09() are timing-dependent
    and likely to fail on fast servers. (Matt Foley via eli)

    HDFS-1845. Symlink comes up as directory after namenode restart.
    (John George via eli)

    HDFS-1666. Disable failing hdfsproxy test TestAuthorizationFilter (todd)

    HDFS-1823. start-dfs.sh script fails if HADOOP_HOME is not set.
    (tomwhite via eli)

    HDFS-1822. Handle editlog opcode conflict with 0.20.203 during upgrade,
    by throwing an error to indicate the editlog needs to be empty.
    (suresh)

    HDFS-1909. TestHDFSCLI fails due to typo in expected output. (tomwhite)

    HDFS-1544. Ivy resolve force mode should be turned off by default.
    (Luke Lu via tomwhite)

    HDFS-1615. seek() on closed DFS input stream throws NullPointerException
    (Scott Carey via todd)

    HDFS-1897. Documentation refers to removed option dfs.network.script
    (Andrew Whang via todd)

    HDFS-1621. Fix references to hadoop-common-${version} in build.xml
    (Jolly Chen via todd)

    HDFS-1891. Disable IPV6 for junit tests to fix TestBackupNode failure.
    (suresh)

    HDFS-1505. saveNamespace appears to succeed even if all directories fail
    to save. (Aaron T. Myers via todd)

    HDFS-1925. SafeModeInfo should use the correct constant instead of a
    hard-coded value for its default. (Joey Echeverria via todd)

    HDFS-1575. Viewing block from web UI is broken. (Aaron T. Myers via todd)
    
    HDFS-1932. Ensure that HDFS configuration deprecations are set up in every
    spot that HDFS configurations are loaded. (Jolly Chen via todd)

    HDFS-1978. All but first option in LIBHDFS_OPTS is ignored. (eli)

    HDFS-1965. IPCs done using block token-based tickets can't reuse
    connections (todd)

    HDFS-1964. Fix incorrect HTML unescaping in DatanodeJspHelper
    (Aaron T. Myers via todd)

    HDFS-1997. Image transfer process misreports client side exceptions.
    (todd via eli)

    HDFS-2000. Missing deprecation for io.bytes.per.checksum.
    (Aaron T. Myers vie eli)

    HDFS-977. DataNode.createInterDataNodeProtocolProxy() guards a log
    at the wrong level. (Harsh J Chouraria via todd)

    HDFS-1936. Layout version change from HDFS-1822 causes upgrade failure.
    (suresh)

    HDFS-1969. Running rollback on new-version namenode destroys the
    namespace. (todd)

    HDFS-2039. TestNameNodeMetrics uses a bad test root path, preventing it
    from running inside Eclipse. (todd)

    HDFS-988. saveNamespace race can corrupt the edits log. (eli)

    HDFS-2071. Use of isConnected() in DataXceiver is invalid. (Kihwal Lee
    via todd)

    HDFS-1952. FSEditLog.open() appears to succeed even if all EDITS
    directories fail. (Andrew Wang via mattf)

    HDFS-2189. Add guava-r09 dependency to ivy/hadoop-hdfs-template.xml
    (Plamen Jeliazkov via shv)

    HDFS-1981. NameNode does not saveNamespace() when editsNew is empty.
    (Uma Maheswara Rao G via shv)

Release 0.21.1 - Unreleased

  IMPROVEMENTS

    HDFS-1411. Correct backup node startup command in hdfs user guide.
    (Ching-Shen Chen via shv)

  BUG FIXES

    HDFS-1363. Eliminate second synchronized sections in appendFile(). (shv)

    HDFS-1413. Fix broken links to HDFS Wiki. (shv)

    HDFS-1420. Clover build doesn't generate per-test coverage (cos)

    HDFS-1444. Test related code of build.xml is error-prone and needs to be
    re-aligned. (cos)

    HDFS-1343. Instrumented build should be concentrated in one build area (cos)

    HDFS-1452. ant compile-contrib is broken (cos)

    HDFS-1474. ant binary-system is broken (cos)

    HDFS-1292. Allow artifacts to be published to the staging Apache Nexus
    Maven Repository.  (Giridharan Kesavan via tomwhite)

    HDFS-1206. TestFiHFlush fails intermittently. (cos)

    HDFS-1548. Fault-injection tests are executed multiple times if invoked
    with run-test-hdfs-fault-inject target (cos)

    HDFS-1552. Remove java5 dependencies from build. (cos) 

    HDFS-996. JUnit tests should never depend on anything in conf (cos)

    HDFS-1612. Update HDFS design documentation for append, quota, symlink,
    block placement and checkpoint/backup node features.  (Joe Crobak
    via szetszwo)

    HDFS-1189. Quota counts missed between clear quota and set quota.
    (John George via szetszwo)

    HDFS-1665. Balancer misuses dfs.heartbeat.interval as milliseconds.
    (szetszwo)

    HDFS-1728. SecondaryNameNode.checkpointSize is in bytes but not in MB.
    (szetszwo)

    HDFS-1596. Replace fs.checkpoint.* with dfs.namenode.checkpoint.*
    in documentations.  (Harsh J Chouraria via szetszwo)

    HDFS-1786. Some cli test cases expect a "null" message
    (Uma Maheswara Rao G via todd)

    HDFS-1855. TestDatanodeBlockScanner.testBlockCorruptionRecoveryPolicy()
    part 2 fails in two different ways. (Matt Foley via eli)

Release 0.21.0 - 2010-08-13

  INCOMPATIBLE CHANGES

    HDFS-538. Per the contract elucidated in HADOOP-6201, throw
    FileNotFoundException from FileSystem::listStatus rather than returning
    null. (Jakob Homan via cdouglas)

    HDFS-602. DistributedFileSystem mkdirs throws FileAlreadyExistsException
    instead of FileNotFoundException. (Boris Shkolnik via suresh)

    HDFS-544. Add a "rbw" subdir to DataNode data directory. (hairong)

    HDFS-576. Block report includes under-construction replicas. (shv)

    HDFS-636. SafeMode counts complete blocks only. (shv)

    HDFS-644. Lease recovery, concurrency support. (shv)

    HDFS-570. Get last block length from a data-node when opening a file
    being written to. (Tsz Wo (Nicholas), SZE via shv)

    HDFS-657. Remove unused legacy data-node protocol methods. (shv)

    HDFS-658. Block recovery for primary data-node. (shv)

    HDFS-660. Remove deprecated methods from InterDatanodeProtocol. (shv)

    HDFS-512. Block.equals() and compareTo() compare blocks based
    only on block Ids, ignoring generation stamps. (shv)

    HDFS-873. Configuration specifies data-node storage directories as URIs.
    (shv)

    HDFS-905. Use the new UserGroupInformation from HDFS-6299. 
    (jghoman via omalley)

    HDFS-984. Persistent delegation tokens. (Jitendra Pandey via shv)

    HDFS-1016. HDFS side change for HADOOP-6569. This jira changes the
    error message on the screen when cat a directory or a 
    non-existent file. (hairong)

  NEW FEATURES

    HDFS-1134. Large-scale Automated Framework. (cos)

    HDFS-436. Introduce AspectJ framework for HDFS code and tests.
    (Konstantin Boudnik via szetszwo)

    HDFS-447. Add LDAP lookup to hdfsproxy. (Zhiyong Zhang via cdouglas)

    HDFS-459. Introduce Job History Log Analyzer. (shv)

    HDFS-461. Tool to analyze file size distribution in HDFS. (shv)

    HDFS-492. Add two JSON JSP pages to the Namenode for providing corrupt
    blocks/replicas information.  (Bill Zeller via szetszwo)

    HDFS-578. Add support for new FileSystem method for clients to get server
    defaults. (Kan Zhang via suresh)

    HDFS-595. umask settings in configuration may now use octal or symbolic 
    instead of decimal. (Jakob Homan via suresh)

    HADOOP-6234. Updated hadoop-core and test jars to propagate new option 
    dfs.umaskmode in configuration. (Jakob Homan via suresh)

    HDFS-235. Add support for byte ranges in HftpFileSystem to serve
    range of bytes from a file. (Bill Zeller via suresh)

    HDFS-385. Add support for an experimental API that allows a module external
    to HDFS to specify how HDFS blocks should be placed. (dhruba)

    HADOOP-4952. Update hadoop-core and test jars to propagate new FileContext
    file system application interface. (Sanjay Radia via suresh).

    HDFS-567. Add block forensics contrib tool to print history of corrupt and
    missing blocks from the HDFS logs.
    (Bill Zeller, Jitendra Nath Pandey via suresh).

    HDFS-610. Support o.a.h.fs.FileContext.  (Sanjay Radia via szetszwo)

    HDFS-536. Support hflush at DFSClient. (hairong)

    HDFS-517. Introduce BlockInfoUnderConstruction to reflect block replica
    states while writing. (shv)

    HDFS-565. Introduce block committing logic during new block allocation
    and file close. (shv)

    HDFS-537. DataNode exposes a replica's meta info to BlockReceiver for the
    support of dfs writes/hflush. It also updates a replica's bytes received,
    bytes on disk, and bytes acked after receiving a packet. (hairong)

    HDFS-585. Datanode should serve up to visible length of a replica for read
    requests.  (szetszwo)

    HDFS-604. Block report processing for append. (shv)

    HDFS-619. Support replica recovery initialization in datanode for the new
    append design.  (szetszwo)

    HDFS-592. Allow clients to fetch a new generation stamp from NameNode for
    pipeline recovery. (hairong)

    HDFS-624. Support a new algorithm for pipeline recovery and pipeline setup
    for append. (hairong)

    HDFS-627. Support replica update in data-node.
    (Tsz Wo (Nicholas), SZE and Hairong Kuang via shv)

    HDFS-642. Support pipeline close and close error recovery. (hairong)

    HDFS-631. Rename configuration keys towards API standardization and
    backward compatibility. (Jitendra Nath Pandey via suresh)

    HDFS-669. Add unit tests framework (Mockito) (cos, Eli Collins)

    HDFS-731. Support new Syncable interface in HDFS. (hairong)

    HDFS-702. Add HDFS implementation of AbstractFileSystem. 
    (Sanjay Radio via suresh)

    HDFS-758. Add decommissioning status page to Namenode Web UI.
    (Jitendra Nath Pandey via suresh)

    HDFS-814. Add an api to get the visible length of a DFSDataInputStream.
    (szetszwo)

    HDFS-654. Add support new atomic rename functionality in HDFS for 
    supporting rename in FileContext. (suresh)

    HDFS-222. Support for concatenating of files into a single file
    without copying. (Boris Shkolnik via hairong)

    HDFS-933. Adds Delegation token based authentication in the NameNode.
    (Kan Zhang via ddas)

    HDFS-935. Adds a real user component in Delegation token.
    (Jitendra Nath Pandey via ddas)

    HDFS-245. Adds a symlink implementation to HDFS. This complements the new 
    symlink feature added in HADOOP-6421 (Eli Collins via Sanjay Radia)

    HDFS-1009. Support Kerberos authorization in HDFSProxy.  (Srikanth
    Sundarrajan via szetszwo)

    HDFS-1091. Implement listStatus that returns an iterator of FileStatus.
    (hairong)

  IMPROVEMENTS

    HDFS-381. Remove blocks from DataNode maps when corresponding file
    is deleted. (Suresh Srinivas via rangadi)

    HDFS-377. Separate codes which implement DataTransferProtocol.
    (szetszwo)

    HDFS-396. NameNode image and edits directories are specified as URIs.
    (Luca Telloli via rangadi)

    HDFS-444. Allow to change probability levels dynamically in the fault
    injection framework.  (Konstantin Boudnik via szetszwo)

    HDFS-352. Documentation for saveNamespace command. (Ravi Phulari via shv)

    HADOOP-6106. Updated hadoop-core and test jars from hudson trunk 
    build #12. (Giridharan Kesavan)

    HDFS-204. Add a new metrics FilesInGetListingOps to the Namenode.
    (Jitendra Nath Pandey via szetszwo)

    HDFS-278. HDFS Outputstream close does not hang forever. (dhruba)

    HDFS-443. Add a new metrics numExpiredHeartbeats to the Namenode.
    (Jitendra Nath Pandey via szetszwo)

    HDFS-475. Add new ant targets for fault injection jars and tests.
    (Konstantin Boudnik via szetszwo)

    HDFS-458. Create a new ant target, run-commit-test.  (Jakob Homan
    via szetszwo)

    HDFS-493. Change build.xml so that the fault-injected tests are executed
    only by the run-test-*-fault-inject targets.  (Konstantin Boudnik via
    szetszwo)

    HDFS-446. Improvements to Offline Image Viewer. (Jakob Homan via shv)

    HADOOP-6160. Fix releaseaudit target to run on specific directories.
    (gkesavan)

    HDFS-501. Use enum to define the constants in DataTransferProtocol.
    (szetszwo)

    HDFS-508. Factor out BlockInfo from BlocksMap. (shv)

    HDFS-510. Rename DatanodeBlockInfo to be ReplicaInfo.
    (Jakob Homan & Hairong Kuang via shv)

    HDFS-500. Deprecate NameNode methods deprecated in NameNodeProtocol.
    (Jakob Homan via shv)

    HDFS-514. Change DFSClient.namenode from public to private.  (Bill Zeller
    via szetszwo)

    HDFS-496. Use PureJavaCrc32 in HDFS.  (Todd Lipcon via szetszwo)

    HDFS-511. Remove redundant block searches in BlockManager. (shv)

    HDFS-504. Update the modification time of a file when the file 
    is closed. (Chun Zhang via dhruba)

    HDFS-498. Add development guide and documentation for the fault injection
    framework.  (Konstantin Boudnik via szetszwo)

    HDFS-524. Further DataTransferProtocol code refactoring.  (szetszwo)

    HDFS-529. Use BlockInfo instead of Block to avoid redundant block searches
    in BlockManager. (shv)

    HDFS-530. Refactor TestFileAppend* to remove code duplication.
    (Konstantin Boudnik via szetszwo)

    HDFS-451. Add fault injection tests for DataTransferProtocol.  (szetszwo)

    HDFS-409. Add more access token tests.  (Kan Zhang via szetszwo)

    HDFS-546. DatanodeDescriptor iterates blocks as BlockInfo. (shv)

    HDFS-457. Do not shutdown datanode if some, but not all, volumes fail.
    (Boris Shkolnik via szetszwo)

    HDFS-548. TestFsck takes nearly 10 minutes to run. (hairong)

    HDFS-539. Refactor fault injeciton pipeline test util for future reuse.
    (Konstantin Boudnik via szetszwo)

    HDFS-552. Change TestFiDataTransferProtocol to junit 4 and add a few new
    tests.  (szetszwo)

    HDFS-563. Simplify the codes in FSNamesystem.getBlockLocations(..).
    (szetszwo)

    HDFS-581. Introduce an iterator over blocks in the block report array.(shv)

    HDFS-549. Add a new target, run-with-fault-inject-testcaseonly, which
    allows an execution of non-FI tests in FI-enable environment.  (Konstantin
    Boudnik via szetszwo)

    HDFS-173. Namenode will not block until a large directory deletion 
    completes. It allows other operations when the deletion is in progress. 
    (suresh)

    HDFS-551. Create new functional test for a block report. (Konstantin
    Boudnik via hairong)

    HDFS-288. Redundant computation in hashCode() implementation.
    (szetszwo via tomwhite)

    HDFS-412. Hadoop JMX usage makes Nagios monitoring impossible.
    (Brian Bockelman via tomwhite)

    HDFS-472. Update hdfsproxy documentation. Adds a setup guide and design
    document. (Zhiyong Zhang via cdouglas)

    HDFS-617. Support non-recursive create().  (Kan Zhang via szetszwo)

    HDFS-618. Support non-recursive mkdir().  (Kan Zhang via szetszwo)

    HDFS-574. Split the documentation between the subprojects.
    (Corinne Chandel via omalley)

    HDFS-598. Eclipse launch task for HDFS. (Eli Collins via tomwhite)

    HDFS-641. Move all of the components that depend on map/reduce to 
    map/reduce. (omalley)

    HDFS-509. Redesign DataNode volumeMap to include all types of Replicas.
    (hairong)

    HDFS-562. Add a test for NameNode.getBlockLocations(..) to check read from
    un-closed file.  (szetszwo)

    HDFS-543. Break FSDatasetInterface#writToBlock() into writeToRemporary,
    writeToRBW, ad append. (hairong)

    HDFS-603. Add a new interface, Replica, which is going to replace the use
    of Block in datanode.  (szetszwo)

    HDFS-589. Change block write protocol to support pipeline recovery.
    (hairong)

    HDFS-652. Replace BlockInfo.isUnderConstruction() with isComplete() (shv)

    HDFS-648. Change some methods in AppendTestUtil to public.  (Konstantin
    Boudnik via szetszwo)

    HDFS-662. Unnecessary info message from DFSClient. (hairong)

    HDFS-518. Create new tests for Append's hflush. (Konstantin Boudnik
    via szetszwo)

    HDFS-688. Add configuration resources to DFSAdmin. (shv)

    HDFS-29. Validate the consistency of the lengths of replica and its file 
    in replica recovery.  (szetszwo)

    HDFS-680. Add new access method to a copy of a block's replica. (shv)

    HDFS-704. Unify build property names to facilitate cross-projects
    modifications (cos)

    HDFS-705. Create an adapter to access some of package-private methods of
    DataNode from tests (cos)

    HDFS-710. Add actions with constraints to the pipeline fault injection
    tests and change SleepAction to support uniform random sleeping over an
    interval.  (szetszwo)

    HDFS-713. Need to properly check the type of the test class from an aspect
    (cos)

    HDFS-716. Define a pointcut for pipeline close and add a few fault
    injection tests to simulate out of memory problem.  (szetszwo)

    HDFS-719. Add 6 fault injection tests for pipeline close to simulate slow
    datanodes and disk errors.  (szetszwo)

    HDFS-616. Create functional tests for new design of the block report. (cos)
    
    HDFS-584. Fail the fault-inject build if any advices are mis-bound. (cos)

    HDFS-730. Add 4 fault injection tests to simulate non-responsive datanode
    and out-of-memory problem for pipeline close ack.  (szetszwo)

    HDFS-728. Create a comprehensive functional test for append. (hairong)

    HDFS-736. commitBlockSynchronization() updates block GS and length 
    in-place. (shv)

    HADOOP-5107. Use Maven ant tasks to publish the subproject jars.
    (Giridharan Kesavan via omalley)

    HDFS-521. Create new tests for pipeline (cos)

    HDFS-764. Places the Block Access token implementation in hdfs project.
    (Kan Zhang via ddas)

    HDFS-787. Upgrade some libraries to be consistent with common and 
    mapreduce. (omalley)

    HDFS-519. Create new tests for lease recovery (cos)

    HDFS-804. New unit tests for concurrent lease recovery (cos)

    HDFS-813. Enable the append test in TestReadWhileWriting.  (szetszwo)

    HDFS-145. Cleanup inconsistent block length handling code in
    FSNameSystem#addStoredBlock. (hairong)

    HDFS-127. Reset failure count in DFSClient for each block acquiring
    operation.  (Igor Bolotin via szetszwo)

    HDFS-520. Create new tests for block recovery. (hairong)

    HDFS-1067. Create block recovery tests that handle errors. (hairong)

    HDFS-1107. Turn on append by default. (shv)

    HDFS-968. Use StringBuilder instead of StringBuffer for better
    performance. (Kay Kay via suresh)
    
    HDFS-703. Replace current fault injection implementation with one
    from (cos)

    HDFS-754. Reduce ivy console output to observable level (cos)

    HDFS-832. HDFS side of HADOOP-6222. (cos)

    HDFS-840. Change tests to use FileContext test helper introduced in
    HADOOP-6394. (Jitendra Nath Pandey via suresh)

    HDFS-685. Use the user-to-groups mapping service in the NameNode. 
    (boryas, acmurthy)

    HDFS-755. Read multiple checksum chunks at once in DFSInputStream.
    (Todd Lipcon via tomwhite)

    HDFS-786. Implement getContentSummary in HftpFileSystem.
    (Tsz Wo (Nicholas), SZE via cdouglas)

    HDFS-587. Add support for specifying queue name in mapreduce tests.
    (Erik Steffl via suresh)

    HDFS-902 Move contrib/raid to MapReduce. (Eli Collins via omalley)

    HDFS-800. The last block of a file under construction may change to the
    COMPLETE state in response to getAdditionalBlock or completeFileInternal.
    (hairong)

    HDFS-899. Delegation Token Implementation
     and corresponding changes in Namenode and DFS Api to issue, 
    renew and cancel delegation tokens. (jnp via boryas)

    HDFS-844. Log the filename when file locking fails. (tomwhite)

    HDFS-914. Refactor DFSOutputStream and DFSInputStream out of DFSClient.
    (Todd Lipcon via tomwhite)

    HDFS-949. Move DelegationToken into Common so that it can be used by
    MapReduce. (omalley)

    HDFS-930. Better error message for DATA_TRANSFER_VERSION mismatched.
    (Kay Kay via szetszwo)

    HDFS-986. Delegation token renewing and cancelling should provide
    meaningful exceptions when there are failures instead of returning 
    false. (omalley)

    HADOOP-6579. Upgrade the commons-codec library to 1.4. (omalley)

    HDFS-991. Allow authentication to the web ui via a delegation token. 
    (omalley)

    HDFS-994. Allow fetching of delegation token from NameNode for hftp.
    (Jakob Homan via acmurthy) 

    HDFS-998. Quote blocks streamed through jsps. (cdouglas)

    HDFS-729. NameNode API to list files that have missing blocks.
    (Rodrigo Schmidt via dhruba)

    HDFS-850. The WebUI display more details about namenode memory usage.
    (Dmytro Molkov via dhruba)

    HDFS-826. The DFSOutputStream has a API that returns the number of
    active datanode(s) in the current pipeline. (dhruba)

    HDFS-985. HDFS should issue multiple RPCs for listing a large
    directory. (hairong)

    HDFS-1043. NNThroughputBenchmark modifications to support benchmarking of
    server-side user group resolution. (shv)

    HDFS-892. Optionally use Avro reflection for Namenode RPC.  This
    is not a complete implementation yet, but rather a starting point.
    (cutting)
    
    HDFS-854. Datanode should scan devices in parallel to generate
    block report. (Dmytro Molkov via jhoman)

    HDFS-1032. fsck has an option to list corrupt files.
    (Andre Oriai via dhruba)

    HDFS-1024. SecondaryNameNode verifies size of fsimage and edits file.
    (Dmytro Molkov via dhruba)
    
    HDFS-1011. hdfsproxy: Improve log messages by restoring the previous
    thread name.  (Srikanth Sundarrajan via szetszwo)

    HDFS-997. Allow datanode storage directory permissions to be configurable.
    (Luke Lu via cdouglas)

    HDFS-1012. hdfsproxy: Support for fully qualified HDFS path in addition to
    simple unqualified path.  (Srikanth Sundarrajan via szetszwo)

    HDFS-933. Namenode should issue a delegation token only for kerberos 
    authenticated clients.(jnp via boryas)

    HDFS-1087. Modify audit log to use a StringBuilder rather than a Formatter.
    (cdouglas)

    HDFS-1083. Update TestHDFSCLI not to expect exception class name
    in error messages. (suresh)

    HDFS-1099. Add test for umask backward compatibility. (suresh)

    HDFS-1092. Use logging rather than System.err in MiniDFSCluster.
    (Kay Kay via jghoman)

    HDFS-1047. Install/deploy source jars to Maven repo. 
    (Patrick Angeles via jghoman)

    HDFS-666. Unit test for FsShell -text. (cdouglas via jghoman)

    HDFS-1054. Remove unnecessary sleep after failure in nextBlockOutputStream.
    (Todd Lipcon via jghoman)

    HDFS-921. Convert TestDFSClientRetries::testNotYetReplicatedErrors
    to Mockito. (jghoman)

    HDFS-1100. Override unwrapException in TestFcHdfsSymlink to test 
    symlink API conformance. (Eli Collins via suresh).

    HDFS-1089. Remove uses of FileContext#isFile, isDirectory, and exists.
    (Eli Collins via hairong)

    HDFS-1028. Efficient splitting of path components reduces the time
    to load in fsimage by 20%. (Dmytro Molkov via dhruba)

    HDFS-1109. HFTP supports filenames that contains the character "+".
    (Dmytro Molkov via dhruba)

    HDFS-853. The HDFS webUI displays the balanced-ness of the cluster.
    (Dmytro Molkov via dhruba)

    HDFS-1126. Change HDFS to depend on Hadoop 'common' artifacts instead
    of 'core'. (tomwhite)

    HDFS-995.  Replace usage of FileStatus#isDir().  (Eli Collins via
    tomwhite)

    HDFS-1161.  Make DN minimum valid volumes configurable.
    (Eli Collins via tomwhite)

    HDFS-1181. Move configuration and script files post split. (tomwhite)

    HDFS-1170.  Add more assertions to TestLargeDirectoryDelete.
    (Steve Loughran via tomwhite)

    HDFS-1199. Extract a subset of tests for smoke (DOA) validation. (cos)

    HDFS-1174. New properties for suspend and resume process. (Vinay Thota via
    cos)

    HDFS-1277. [Herriot] New property for multi user list. (Vinay Thota via
    cos)

    HDFS-806. Add new unit tests to the 10-mins 'run-commit-test' target (cos)

  OPTIMIZATIONS

    HDFS-946. NameNode should not return full path name when lisitng a
    diretory or getting the status of a file. (hairong)

  BUG FIXES

    HDFS-76. Better error message to users when commands fail because of 
    lack of quota. Allow quota to be set even if the limit is lower than
    current consumption. (Boris Shkolnik via rangadi)

    HADOOP-4687. HDFS is split from Hadoop Core. It is a subproject under 
    Hadoop (Owen O'Malley)

    HADOOP-6096. Fix Eclipse project and classpath files following project
    split. (tomwhite)

    HDFS-195. Handle expired tokens when write pipeline is reestablished.
    (Kan Zhang via rangadi)

    HDFS-181. Validate src path in FSNamesystem.getFileInfo(..).  (Todd
    Lipcon via szetszwo)

    HDFS-441. Remove TestFTPFileSystem.  (szetszwo)

    HDFS-440. Fix javadoc broken links in DFSClient.  (szetszwo)

    HDFS-480. Fix a typo in the jar name in build.xml.  
    (Konstantin Shvachko via gkesavan)

    HDFS-438. Check for NULL before invoking GenericArgumentParser in
    DataNode. (Raghu Angadi)

    HDFS-415. BlockReceiver hangs in case of certain runtime exceptions.
    (Konstantin Boudnik via rangadi)

    HDFS-462. loadFSImage should close edits file. (Jakob Homan via shv)

    HDFS-489. Update TestHDFSCLI for the -skipTrash option in rm. (Jakob Homan
    via szetszwo)

    HDFS-445. pread() does not pick up changes to block locations. 
    (Kan Zhang via rangadi) 

    HDFS-463. CreateEditLog utility broken after HDFS-396 (URI for
    FSImage). (Suresh Srinivas via rangadi)

    HDFS-484. Fix bin-package and package target to package jar files.
    (gkesavan)

    HDFS-490. Eliminate the deprecated warnings introduced by H-5438.
    (He Yongqiang via szetszwo)

    HDFS-119. Fix a bug in logSync(), which causes NameNode block forever.
    (Suresh Srinivas via shv)

    HDFS-534. Include avro in ivy.  (szetszwo)

    HDFS-532. Allow applications to know that a read request failed 
    because block is missing. (dhruba)

    HDFS-561. Fix write pipeline READ_TIMEOUT in DataTransferProtocol.
    (Kan Zhang via szetszwo)

    HDFS-553. BlockSender reports wrong failed position in ChecksumException.
    (hairong)

    HDFS-568. Set mapred.job.tracker.retire.jobs to false in
    src/test/mapred-site.xml for mapreduce tests to run.  (Amareshwari
    Sriramadasu via szetszwo)
 
    HDFS-15. All replicas end up on 1 rack. (Jitendra Nath Pandey via hairong)
 
    HDFS-586. TestBlocksWithNotEnoughRacks sometimes fails.
    (Jitendra Nath Pandey via hairong)

    HADOOP-6243. Fixed a NullPointerException in handling deprecated keys.
    (Sreekanth Ramakrishnan via yhemanth)

    HDFS-605. Do not run fault injection tests in the run-test-hdfs-with-mr
    target.  (Konstantin Boudnik via szetszwo)

    HDFS-606. Fix ConcurrentModificationException in invalidateCorruptReplicas()
    (shv)

    HDFS-601. TestBlockReport obtains data directories directly from
    MiniHDFSCluster. (Konstantin Boudnik via shv)

    HDFS-614. TestDatanodeBlockScanner obtains data directories directly from
    MiniHDFSCluster. (shv)

    HDFS-612. Remove the use of org.mortbay.log.Log in FSDataset.  (szetszwo)

    HDFS-622. checkMinReplication should count live nodes only. (shv)

    HDFS-629. Remove ReplicationTargetChooser.java along with fixing 
    import warnings generated by Eclipse. (dhruba)

    HDFS-637. DataNode sends a Success ack when block write fails. (hairong)

    HDFS-640. Fixed TestHDFSFileContextMainOperations.java build failure. (suresh)

    HDFS-547. TestHDFSFileSystemContract#testOutputStreamClosedTwice
    sometimes fails with CloseByInterruptException. (hairong)

    HDFS-588. Fix TestFiDataTransferProtocol and TestAppend2 failures. (shv)

    HDFS-550. DataNode restarts may introduce corrupt/duplicated/lost replicas
    when handling detached replicas. (hairong)

    HDFS-659. If the the last block is not complete, update its length with
    one of its replica's length stored in datanode.  (szetszwo)

    HDFS-649. Check null pointers for DataTransferTest.  (Konstantin Boudnik
    via szetszwo)

    HDFS-661. DataNode upgrade fails on non-existant current directory.
    (hairong)

    HDFS-597. Mofication introduced by HDFS-537 breakes an advice binding in
    FSDatasetAspects.  (Konstantin Boudnik via szetszwo)

    HDFS-665. TestFileAppend2 sometimes hangs. (hairong)

    HDFS-676. Fix NPE in FSDataset.updateReplicaUnderRecovery() (shv)

    HDFS-673. BlockReceiver#PacketResponder should not remove a packet from
    the ack queue before its ack is sent. (hairong)

    HDFS-682. Fix bugs in TestBlockUnderConstruction.  (szetszwo)

    HDFS-668. TestFileAppend3#TC7 sometimes hangs. (hairong)

    HDFS-679. Appending to a partial chunk incorrectly assumes the
    first packet fills up the partial chunk. (hairong)

    HDFS-722. Fix callCreateBlockWriteStream pointcut in FSDatasetAspects.
    (szetszwo)

    HDFS-690. TestAppend2#testComplexAppend failed on "Too many open files".
    (hairong)

    HDFS-725. Support the build error fix for HADOOP-6327.  (Sanjay Radia via
    szetszwo)

    HDFS-625. Fix NullPointerException thrown from ListPathServlet. (suresh)

    HDFS-735. TestReadWhileWriting has wrong line termination symbols (cos)

    HDFS-691. Fix an overflow error in DFSClient.DFSInputStream.available().
    (szetszwo)

    HDFS-733. TestBlockReport fails intermittently. (cos)

    HDFS-774. Intermittent race condition in TestFiPipelines (cos)

    HDFS-741. TestHFlush test doesn't seek() past previously written part of
    the file (cos, szetszwo)

    HDFS-706. Intermittent failures in TestFiHFlush (cos)
 
    HDFS-646. Fix test-patch failure by adding test-contrib ant target.
    (gkesavan)

    HDFS-791. Build is broken after HDFS-787 patch has been applied (cos)

    HDFS-792. TestHDFSCLI is failing. (Todd Lipcon via cos)

    HDFS-781. Namenode metrics PendingDeletionBlocks is not decremented.
    (Suresh)

    HDFS-192. Fix TestBackupNode failures. (shv)

    HDFS-797. TestHDFSCLI much slower after HDFS-265 merge. (Todd Lipcon via cos)

    HDFS-824. Stop lease checker in TestReadWhileWriting.  (szetszwo)

    HDFS-823. CheckPointer should use addInternalServlet for image-fetching
    servlet (jghoman)

    HDFS-456. Fix URI generation for windows file paths. (shv)

    HDFS-812. FSNamesystem#internalReleaseLease throws NullPointerException on
    a single-block file's lease recovery. (cos)

    HDFS-724. Pipeline hangs if one of the block receiver is not responsive.
    (hairong)

    HDFS-564. Adding pipeline tests 17-35. (hairong)

    HDFS-849. TestFiDataTransferProtocol2#pipeline_Fi_18 sometimes fails.
    (hairong)

    HDFS-762. Balancer causes Null Pointer Exception. 
    (Cristian Ivascu via dhruba)

    HDFS-868. Fix link to Hadoop Upgrade Wiki. (Chris A. Mattmann via shv)
    
    HDFS-880. TestNNLeaseRecovery fails on windows (cos, shv)

    HDFS-699. Primary datanode should compare replicas' on disk lengths.
    (hairong)

    HDFS-897. Fix a bug related to generation stamp comparison in 
    ReplicasMap. (suresh)

    HDFS-793. Data node should receive the whole packet ack message before it
    constructs and sends its own ack message for the packet. (hairong)

    HDFS-101. DFS write pipeline: DFSClient sometimes does not detect second
    datanode failure. (hairong)

    HDFS-822. Appends to already-finalized blocks can rename across volumes.
    (hairong)

    HDFS-1046. Fix Tomcat version in hdfsproxy/build.xml.  (Srikanth
    Sundarrajan via szetszwo)

    HDFS-1072. Fix TestReadWhileWriting failure. (Erik Steffl via shv)

    HDFS-913. Rename fault injection test TestRename.java to TestFiRename.java
    to include it in tests run by ant target run-test-hdfs-fault-inject.
    (suresh)
  
    HDFS-695. RaidNode should read in configuration from hdfs-site.xml.
    (dhruba)

    HDFS-726. Eclipse .classpath template has outdated jar files and is
    missing some new ones. (cos)

    HDFS-750. Fix build failure due to TestRename. (suresh)

    HDFS-712. Move libhdfs from mapreduce subproject to hdfs subproject.
    (Eli Collins via dhruba)

    HDFS-757. Enable Unit test for HDFS Raid. (dhruba)

    HDFS-611. Prevent DataNode heartbeat times from increasing even when
    the DataNode has many blocks to delete. (Zheng Shao via dhruba)

    HDFS-751. Fix TestCrcCorruption to pick up the correct datablocks to
    corrupt. (dhruba)
    
    HDFS-763. Fix slightly misleading report from DataBlockScanner 
    about corrupted scans. (dhruba)

    HDFS-727. bug setting block size hdfsOpenFile (Eli Collins via cos)

    HDFS-756. libhdfs unit tests do not run. (Eli Collins via cos)

    HDFS-783. libhdfs tests brakes code coverage runs with Clover (cos)

    HDFS-785. Add Apache license to several namenode unit tests. 
    (Ravi Phulari via jghoman)

    HDFS-802. Update Eclipse configuration to match changes to Ivy
    configuration (Edwin Chan via cos)

    HDFS-423. Unbreak FUSE build and fuse_dfs_wrapper.sh (Eli Collins via cos)

    HDFS-825. Build fails to pull latest hadoop-core-* artifacts (cos)

    HDFS-94. The Heap Size printed in the NameNode WebUI is accurate.
    (Dmytro Molkov via dhruba)

    HDFS-767. An improved retry policy when the DFSClient is unable to fetch a
    block from the datanode.  (Ning Zhang via dhruba)

    HDFS-775. FSDataset calls getCapacity() twice. (stevel)
    
    HDFS-885. Datanode toString() NPEs on null dnRegistration. (stevel)

    HDFS-877. Client-driven block verification not functioning. (Todd
    Lipcon via hairong)

    HDFS-630. In DFSOutputStream.nextBlockOutputStream(), the client can
    exclude specific datanodes when locating the next block.
    (Cosmin Lehene via Stack)

    HDFS-922. Remove unnecessary semicolon added by HDFS-877 that causes
    problems for Eclipse compilation. (jghoman)

    HDFS-927  DFSInputStream retries too many times for new block locations
    (Todd Lipcon via Stack)

    HDFS-938. Replace calls to UGI.getUserName() with UGI.getShortUserName()
    (jghoman)

    HDFS-894. DatanodeID.ipcPort is not updated when existing node 
    re-registers. (Todd Lipcon via tomwhite)

    HDFS-965. Split TestDelegationToken in to two parts and fix configuration
    to allow proxy users in the test. (Jitendra Pandey via omalley)

    HDFS-999. Secondary namenode should login using kerberos if security is 
    configured (boryas)

    HDFS-856. Hardcoded replication level for new files in fuse-dfs.
    (Brian Bockelman via tomwhite)

    HDFS-857. Incorrect type for fuse-dfs capacity can cause "df" to return
    negative values on 32-bit machines. (Brian Bockelman via tomwhite)

    HDFS-858. Incorrect return codes for fuse-dfs. (Brian Bockelman via
    tomwhite)

    HDFS-859. fuse-dfs utime behavior causes issues with tar.
    (Brian Bockelman via tomwhite)

    HDFS-861. fuse-dfs does not support O_RDWR. (Brian Bockelman via tomwhite)

    HDFS-961. dfs_readdir incorrectly parses paths. (Eli Collins via tomwhite)

    HDFS-1015. Fix intermittent failure in TestSecurityTokenEditLog.
    (Jitendra Nath Pandey via suresh)

    HDFS-939. libhdfs test is broken. (Eli Collins via tomwhite)
    
    HDFS-1074. hdfsproxy: Fix bugs in TestProxyUtil.  (Srikanth Sundarrajan
    via szetszwo)

    HDFS-481. hdfsproxy: Bug Fixes + HdfsProxy to use proxy user to
    impresonate the real user.  (Srikanth Sundarrajan via szetszwo)

    HDFS-482. Move HsftpFileSystem's ssl.client.do.not.authenticate.server
    configuration setting to ssl-client.xml.  (Srikanth Sundarrajan via
    szetszwo)

    HDFS-1010. hdfsproxy: Retrieve groups from UnixUserGroupInformation
    instead of LdapEntry.  (Srikanth Sundarrajan via szetszwo)

    HDFS-466. hdfs_write infinite loop when dfs fails and cannot write
    files > 2 GB. (Pete Wyckoff via tomwhite)

    HDFS-651. HDFS Docs - fix listing of docs in the doc menu.
    (Corinne Chandel via tomwhite)

    HDFS-1014. Error in reading delegation tokens from edit logs.
    (Jitendra Nath Pandey via jhoman)

    HDFS-1088. Prevent renaming a symbolik link to its target.
    (Eli Collins via suresh)

    HDFS-966. NameNode does not recovers lease when it is in safemode.
    (dhruba)

    HDFS-833. Datanode shutdown should log problems with Storage.unlockAll()
    (Steve Loughran via dhruba)

    HDFS-1101. TestDiskError.testLocalDirs() fails. (cdouglas via jghoman)

    HDFS-1031. Enhance the webUi to list a few of the corrupted files in HDFS.
    (Andre Orian via dhruba)

    HDFS-1078. Create static and dynamic versions of libhdfs.
    (Sam Rash via dhruba)

    HDFS-1104. Fsck triggers full GC on NameNode. (hairong)

    HDFS-1141. Closing a file is successful only if the client still has a
    valid lease. (Todd Lipcon via dhruba)

    HDFS-1138. Prevent erroneous updation of modification time of a directory
    when fsimage loads. (Dmytro Molkov via dhruba)

    HDFS-1000. Updates libhdfs to the new API for UGI (ddas)

    HDFS-609. Create a file with the append flag does not work in HDFS.
    (tomwhite)

    HDFS-1255. Fix failing test-libhdfs.sh test. (tomwhite)

    HDFS-1256. libhdfs is missing from the tarball. (tomwhite)

    HDFS-1057. Concurrent readers hit ChecksumExceptions if following a
    writer to very end of file. (sam rash via hairong)

    HDFS-1212. Harmonize HDFS JAR library versions with Common. (tomwhite)

    HDFS-1159. clean-cache target removes wrong ivy cache (cos)

    HDFS-1193. -mvn-system-deploy target is broken which inturn fails the
    mvn-deploy task leading to unstable mapreduce build (Giridharan
    Kesavan via cos)

    HDFS-1299. 'compile-fault-inject' never should be called directly. (cos)

    HDFS-1311. Running tests with 'testcase' cause triple execution of the
    same test case (Cos)

    HDFS-1267. fuse-dfs does not compile. (Devaraj Das via tomwhite)

    HDFS-1598.  Directory listing on hftp:// does not show .*.crc files.
    (szetszwo)

    HDFS-1750. ListPathsServlet should not use HdfsFileStatus.getLocalName()
    to get file name since it may return an empty string.  (szetszwo)

Release 0.20.3 - 2011-1-5

  IMPROVEMENTS

  BUG FIXES

    HDFS-955. New implementation of saveNamespace() to avoid loss of edits 
    when name-node fails during saving. (shv)

    HDFS-1041. DFSClient.getFileChecksum(..) should retry if connection to
    the first datanode fails.  (szetszwo)

    HDFS-909. Wait until edits syncing is finishes before purging edits.
    (Todd Lipcon via shv)

    HDFS-1258. Clearing namespace quota on "/" corrupts fs image.
    (Aaron T. Myers via szetszwo)

    HDFS-132. Fix namenode to not report files deleted metrics for deletions
    done while replaying edits during startup. (suresh & shv)

    HDFS-1406. TestCLI fails on Ubuntu with default /etc/hosts. (cos)

Release 0.20.2 - 2009-09-01

  IMPROVEMENTS

    HDFS-737. Add full path name of the file to the block information and 
    summary of total number of files, blocks, live and deadnodes to 
    metasave output. (Jitendra Nath Pandey via suresh)

    HDFS-919. Create test to validate the BlocksVerified metric (Gary Murry
    via cos)

    HDFS-907. Add tests for getBlockLocations and totalLoad metrics.
    (Ravi Phulari via cos)
    
  BUG FIXES

    HDFS-686. NullPointerException is thrown while merging edit log and image.
    (hairong)

    HDFS-677. Rename failure when both source and destination quota exceeds
    results in deletion of source. (suresh)

    HDFS-709. Fix TestDFSShell failure due to rename bug introduced by 
    HDFS-677. (suresh)

    HDFS-579. Fix DfsTask to follow the semantics of 0.19, regarding non-zero
    return values as failures. (Christian Kunz via cdouglas)

    HDFS-723. Fix deadlock in DFSClient#DFSOutputStream. (hairong)

    HDFS-596. Fix memory leak in hdfsFreeFileInfo() for libhdfs.
    (Zhang Bingjun via dhruba)

    HDFS-185. Disallow chown, chgrp, chmod, setQuota, and setSpaceQuota when
    name-node is in safemode. (Ravi Phulari via shv)

    HDFS-187. Initialize secondary namenode http address in TestStartup.
    (Todd Lipcon via szetszwo)

    HDFS-464. Fix memory leaks in libhdfs. (Christian Kunz via suresh)

    HDFS-1377. Quota bug for partial blocks allows quotas to be violated. (eli)

Release 0.20.1 - 2009-09-01

  IMPROVEMENTS

    HDFS-438. Improve help message for space quota command. (Raghu Angadi)

  BUG FIXES

    HDFS-167. Fix a bug in DFSClient that caused infinite retries on write.
    (Bill Zeller via szetszwo)

    HDFS-527. Remove/deprecate unnecessary DFSClient constructors.  (szetszwo)

    HDFS-525. The SimpleDateFormat object in ListPathsServlet is not thread
    safe. (Suresh Srinivas and cdouglas)

    HDFS-761. Fix failure to process rename operation from edits log due to 
    quota verification. (suresh)