[GitHub] attilapiros commented on a change in pull request #23614: [SPARK-26689][CORE]Support blacklisting bad disk directory and retry in DiskBlockManager

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attilapiros commented on a change in pull request #23614: [SPARK-26689][CORE]Support blacklisting bad disk directory and retry in DiskBlockManager
URL: https://github.com/apache/spark/pull/23614#discussion_r253428199
 
 

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 File path: core/src/main/scala/org/apache/spark/storage/DiskBlockManager.scala
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 @@ -48,32 +55,71 @@ private[spark] class DiskBlockManager(conf: SparkConf, deleteFilesOnStop: Boolea
   // of subDirs(i) is protected by the lock of subDirs(i)
   private val subDirs = Array.fill(localDirs.length)(new Array[File](subDirsPerLocalDir))
 
+  private[spark] val badDirs = ArrayBuffer[File]()
+  private[spark] val dirToBlacklistExpiryTime = new HashMap[File, Long]
+  // Filename hash to dirId, it should be small enough to put into memory
+  private[spark] val migratedDirIdIndex = new ConcurrentHashMap[Int, Int].asScala
+
   private val shutdownHook = addShutdownHook()
 
   /** Looks up a file by hashing it into one of our local subdirectories. */
   // This method should be kept in sync with
   // org.apache.spark.network.shuffle.ExternalShuffleBlockResolver#getFile().
   def getFile(filename: String): File = {
+    var mostRecentFailure: Exception = null
     // Figure out which local directory it hashes to, and which subdirectory in that
     val hash = Utils.nonNegativeHash(filename)
-    val dirId = hash % localDirs.length
+    val dirId = migratedDirIdIndex.getOrElse(hash, hash % localDirs.length)
     val subDirId = (hash / localDirs.length) % subDirsPerLocalDir
 
     // Create the subdirectory if it doesn't already exist
     val subDir = subDirs(dirId).synchronized {
+      // Update blacklist
+      val now = clock.getTimeMillis()
+      val unblacklisted = badDirs.filter(now >= dirToBlacklistExpiryTime(_))
+      unblacklisted.foreach { dir =>
+        badDirs -= dir
+        dirToBlacklistExpiryTime.remove(dir)
+      }
+
       val old = subDirs(dirId)(subDirId)
       if (old != null) {
         old
       } else {
-        val newDir = new File(localDirs(dirId), "%02x".format(subDirId))
-        if (!newDir.exists() && !newDir.mkdir()) {
-          throw new IOException(s"Failed to create local dir in $newDir.")
+        assert(!migratedDirIdIndex.contains(dirId))
+        var succeed = false
+        var newDir: File = null
+        for (attempt <- 0 until maxRetries if !succeed) {
+          val isBlacklisted = badDirs.contains(localDirs(dirId))
+          val goodDirId = if (isBlacklisted) {
+            localDirs.indexWhere(!badDirs.contains(_))
+          } else {
+            dirId
+          }
+          try {
+            if (goodDirId < 0) {
+              throw new IOException("No good disk directories available")
+            }
+            newDir = new File(localDirs(goodDirId), "%02x".format(subDirId))
+            if (!newDir.exists() && !newDir.mkdir()) {
+              throw new IOException(s"Failed to create local dir in $newDir.")
+            }
+            subDirs(goodDirId)(subDirId) = newDir
+            if (goodDirId != dirId) {
+              migratedDirIdIndex.put(hash, goodDirId)
+            }
+            succeed = true
+          } catch {
+            case e: IOException =>
+              logError(s"Failed to looking up file $filename in attempt $attempt", e)
+              badDirs += localDirs(dirId)
 
 Review comment:
   @liupc race condition still possible if two `getFile` calls are using different `dirId` (so the locks are different) and both directories are corrupt  

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