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HADOOP-18636 LocalDirAllocator cannot recover from directory tree deletion (#5412) 

Even though DiskChecker.mkdirsWithExistsCheck() will create the directory tree,
it is only called *after* the enumeration of directories with available
space has completed.

Directories which don't exist are reported as having 0 space, therefore
the mkdirs code is never reached.

Adding a simple mkdirs() -without bothering to check the outcome-
ensures that if a dir has been deleted then it will be reconstructed
if possible. If it can't it will still have 0 bytes of space
reported and so be excluded from the allocation.

Contributed by Steve Loughran
This commit is contained in:
Steve Loughran 2023-02-22 11:48:12 +00:00 committed by GitHub
parent 49b8ac19f2
commit 11a220c6e7
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2 changed files with 27 additions and 1 deletions
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9
hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/LocalDirAllocator.java
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@ -414,7 +414,14 @@ public class LocalDirAllocator {
//build the "roulette wheel"
for(int i =0; i < ctx.dirDF.length; ++i) {
availableOnDisk[i] = ctx.dirDF[i].getAvailable();
final DF target = ctx.dirDF[i];
// attempt to recreate the dir so that getAvailable() is valid
// if it fails, getAvailable() will return 0, so the dir will
// be declared unavailable.
// return value is logged at debug to keep spotbugs quiet.
final boolean b = new File(target.getDirPath()).mkdirs();
LOG.debug("mkdirs of {}={}", target, b);
availableOnDisk[i] = target.getAvailable();
totalAvailable += availableOnDisk[i];
}

19
hadoop-common-project/hadoop-common/src/test/java/org/apache/hadoop/fs/TestLocalDirAllocator.java
View File

@ -548,5 +548,24 @@ public class TestLocalDirAllocator {
"p1/x", Long.MAX_VALUE - 1), "Expect a DiskErrorException.",
() -> dirAllocator.getLocalPathForWrite("p1/x", Long.MAX_VALUE - 1, conf));
}
/**
* Test for HADOOP-18636 LocalDirAllocator cannot recover from directory tree deletion.
*/
@Test(timeout = 30000)
public void testDirectoryRecovery() throws Throwable {
String dir0 = buildBufferDir(ROOT, 0);
String subdir = dir0 + "/subdir1/subdir2";
conf.set(CONTEXT, subdir);
// get local path and an ancestor
final Path pathForWrite = dirAllocator.getLocalPathForWrite("file", -1, conf);
final Path ancestor = pathForWrite.getParent().getParent();
// delete that ancestor
localFs.delete(ancestor, true);
// and expect to get a new file back
dirAllocator.getLocalPathForWrite("file2", -1, conf);
}
}