This patch make DistributedRaidFileSystem find the location of missing/corrupt data correctly.

ant test result:

All but org.apache.hadoop.streaming.TestUlimit passed. TestUlimit failure is unrelated to this.

ant test-patch result:

[exec] +1 overall.
[exec]
[exec] +1 @author. The patch does not contain any @author tags.
[exec]
[exec] +1 tests included. The patch appears to include 2 new or modified tests.
[exec]
[exec] +1 javadoc. The javadoc tool did not generate any warning messages.
[exec]
[exec] +1 javac. The applied patch does not increase the total number of javac compiler warnings.
[exec]
[exec] +1 findbugs. The patch does not introduce any new Findbugs warnings.
[exec]
[exec] +1 release audit. The applied patch does not increase the total number of release audit warnings.
[exec]
[exec] +1 system tests framework. The patch passed system tests framework compile.
[exec]
[exec]
[exec]
[exec]
[exec] ======================================================================
[exec] ======================================================================
[exec] Finished build.
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Ram: Can you add one more unit test that corrupt more than one block in the stripe?

Modified test to corrupt two blocks in the same stripe and ensure failure.
The test found an additional issue - need to disable caching to force the use of DFS.

+1 Looks good to me. Let's wait for your test results.

Test results under src/contrib/raid:

test-junit:
[junit] WARNING: multiple versions of ant detected in path for junit
[junit] jar:file:/home/rvadali/local/external/ant/lib/ant.jar!/org/apache/tools/ant/Project.class
[junit] and jar:file:/home/rvadali/.ivy2/cache/ant/ant/jars/ant-1.6.5.jar!/org/apache/tools/ant/Project.class
[junit] Running org.apache.hadoop.hdfs.TestRaidDfs
[junit] Tests run: 2, Failures: 0, Errors: 0, Time elapsed: 14.223 sec
[junit] Running org.apache.hadoop.raid.TestRaidHar
[junit] Tests run: 1, Failures: 0, Errors: 0, Time elapsed: 91.264 sec
[junit] Running org.apache.hadoop.raid.TestRaidNode
[junit] Tests run: 3, Failures: 0, Errors: 0, Time elapsed: 62.755 sec
[junit] Running org.apache.hadoop.raid.TestRaidPurge
[junit] Tests run: 1, Failures: 0, Errors: 0, Time elapsed: 23.959 sec

test:

BUILD SUCCESSFUL
Total time: 3 minutes 25 seconds

result of ant test-patch:

[exec]
[exec]
[exec]
[exec] +1 overall.
[exec]
[exec] +1 @author. The patch does not contain any @author tags.
[exec]
[exec] +1 tests included. The patch appears to include 2 new or modified tests.
[exec]
[exec] +1 javadoc. The javadoc tool did not generate any warning messages.
[exec]
[exec] +1 javac. The applied patch does not increase the total number of javac compiler warnings.
[exec]
[exec] +1 findbugs. The patch does not introduce any new Findbugs warnings.
[exec]
[exec] +1 release audit. The applied patch does not increase the total number of release audit warnings.
[exec]
[exec] +1 system tests framework. The patch passed system tests framework compile.
[exec]
[exec]
[exec]
[exec]
[exec] ======================================================================
[exec] ======================================================================
[exec] Finished build.
[exec] ======================================================================
[exec] ======================================================================
[exec]
[exec]

BUILD SUCCESSFUL
Total time: 18 minutes 27 seconds

Looks good.
Let's wait for a few days to see if we get further comments. Then I will commit it.

I just committed this. Thanks, Ram.