HADOOP-13427. Eliminate needless uses of FileSystem#{exists(), isFile(), isDirectory()}. Contributed by Steve Loughran and Mingliang Liu

(cherry picked from commit 5af572b6443715b7a741296c1bd520a1840f9a7c)

hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/crypto/key/JavaKeyStoreProvider.java

@@ -36,6 +36,7 @@ import com.google.common.annotations.VisibleForTesting;
 
 import javax.crypto.spec.SecretKeySpec;
 
+import java.io.FileNotFoundException;
 import java.io.IOException;
 import java.io.ObjectInputStream;
 import java.io.ObjectOutputStream;
@@ -167,9 +168,9 @@ public class JavaKeyStoreProvider extends KeyProvider {
       // rewrite the keystore in flush()
       permissions = perm;
     } catch (KeyStoreException e) {
-      throw new IOException("Can't create keystore", e);
+      throw new IOException("Can't create keystore: " + e, e);
     } catch (GeneralSecurityException e) {
-      throw new IOException("Can't load keystore " + path, e);
+      throw new IOException("Can't load keystore " + path + " : " + e , e);
     }
   }
 
@@ -190,9 +191,7 @@ public class JavaKeyStoreProvider extends KeyProvider {
     try {
       perm = loadFromPath(path, password);
       // Remove _OLD if exists
-      if (fs.exists(backupPath)) {
-        fs.delete(backupPath, true);
-      }
+      fs.delete(backupPath, true);
       LOG.debug("KeyStore loaded successfully !!");
     } catch (IOException ioe) {
       // If file is corrupted for some reason other than
@@ -260,9 +259,7 @@ public class JavaKeyStoreProvider extends KeyProvider {
         LOG.debug(String.format("KeyStore loaded successfully from '%s'!!",
             pathToLoad));
       }
-      if (fs.exists(pathToDelete)) {
-        fs.delete(pathToDelete, true);
-      }
+      fs.delete(pathToDelete, true);
     } catch (IOException e) {
       // Check for password issue : don't want to trash file due
       // to wrong password
@@ -539,13 +536,15 @@ public class JavaKeyStoreProvider extends KeyProvider {
         return;
       }
       // Might exist if a backup has been restored etc.
-      if (fs.exists(newPath)) {
+      try {
         renameOrFail(newPath, new Path(newPath.toString()
             + "_ORPHANED_" + System.currentTimeMillis()));
+      } catch (FileNotFoundException ignored) {
       }
-      if (fs.exists(oldPath)) {
+      try {
         renameOrFail(oldPath, new Path(oldPath.toString()
             + "_ORPHANED_" + System.currentTimeMillis()));
+      } catch (FileNotFoundException ignored) {
       }
       // put all of the updates into the keystore
       for(Map.Entry<String, Metadata> entry: cache.entrySet()) {
@@ -601,9 +600,7 @@ public class JavaKeyStoreProvider extends KeyProvider {
     // Rename _NEW to CURRENT
     renameOrFail(newPath, path);
     // Delete _OLD
-    if (fs.exists(oldPath)) {
-      fs.delete(oldPath, true);
-    }
+    fs.delete(oldPath, true);
   }
 
   protected void writeToNew(Path newPath) throws IOException {
@@ -623,12 +620,12 @@ public class JavaKeyStoreProvider extends KeyProvider {
 
   protected boolean backupToOld(Path oldPath)
       throws IOException {
-    boolean fileExisted = false;
-    if (fs.exists(path)) {
+    try {
       renameOrFail(path, oldPath);
-      fileExisted = true;
+      return true;
+    } catch (FileNotFoundException e) {
+      return false;
     }
-    return fileExisted;
   }
 
   private void revertFromOld(Path oldPath, boolean fileExisted)

hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/FileUtil.java

@@ -22,6 +22,7 @@ import java.io.BufferedInputStream;
 import java.io.BufferedOutputStream;
 import java.io.File;
 import java.io.FileInputStream;
+import java.io.FileNotFoundException;
 import java.io.FileOutputStream;
 import java.io.IOException;
 import java.io.InputStream;
@@ -326,14 +327,15 @@ public class FileUtil {
       return copy(srcFS, srcs[0], dstFS, dst, deleteSource, overwrite, conf);
 
     // Check if dest is directory
-    if (!dstFS.exists(dst)) {
-      throw new IOException("`" + dst +"': specified destination directory " +
-                            "does not exist");
-    } else {
+    try {
       FileStatus sdst = dstFS.getFileStatus(dst);
       if (!sdst.isDirectory()) 
         throw new IOException("copying multiple files, but last argument `" +
                               dst + "' is not a directory");
+    } catch (FileNotFoundException e) {
+      throw new IOException(
+          "`" + dst + "': specified destination directory " +
+              "does not exist", e);
     }
 
     for (Path src : srcs) {
@@ -518,8 +520,13 @@ public class FileUtil {
 
   private static Path checkDest(String srcName, FileSystem dstFS, Path dst,
       boolean overwrite) throws IOException {
-    if (dstFS.exists(dst)) {
-      FileStatus sdst = dstFS.getFileStatus(dst);
+    FileStatus sdst;
+    try {
+      sdst = dstFS.getFileStatus(dst);
+    } catch (FileNotFoundException e) {
+      sdst = null;
+    }
+    if (null != sdst) {
       if (sdst.isDirectory()) {
         if (null == srcName) {
           throw new IOException("Target " + dst + " is a directory");

hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/RawLocalFileSystem.java

@@ -208,9 +208,7 @@ public class RawLocalFileSystem extends FileSystem {
   
   @Override
   public FSDataInputStream open(Path f, int bufferSize) throws IOException {
-    if (!exists(f)) {
-      throw new FileNotFoundException(f.toString());
-    }
+    getFileStatus(f);
     return new FSDataInputStream(new BufferedFSInputStream(
         new LocalFSFileInputStream(f), bufferSize));
   }
@@ -274,9 +272,6 @@ public class RawLocalFileSystem extends FileSystem {
   @Override
   public FSDataOutputStream append(Path f, int bufferSize,
       Progressable progress) throws IOException {
-    if (!exists(f)) {
-      throw new FileNotFoundException("File " + f + " not found");
-    }
     FileStatus status = getFileStatus(f);
     if (status.isDirectory()) {
       throw new IOException("Cannot append to a diretory (=" + f + " )");
@@ -383,17 +378,18 @@ public class RawLocalFileSystem extends FileSystem {
     // platforms (notably Windows) do not provide this behavior, so the Java API
     // call renameTo(dstFile) fails. Delete destination and attempt rename
     // again.
-    if (this.exists(dst)) {
+    try {
       FileStatus sdst = this.getFileStatus(dst);
       if (sdst.isDirectory() && dstFile.list().length == 0) {
         if (LOG.isDebugEnabled()) {
           LOG.debug("Deleting empty destination and renaming " + src + " to " +
-            dst);
+              dst);
         }
         if (this.delete(dst, false) && srcFile.renameTo(dstFile)) {
           return true;
         }
       }
+    } catch (FileNotFoundException ignored) {
     }
     return false;
   }

hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/TrashPolicyDefault.java

@@ -121,9 +121,8 @@ public class TrashPolicyDefault extends TrashPolicy {
     if (!path.isAbsolute())                       // make path absolute
       path = new Path(fs.getWorkingDirectory(), path);
 
-    if (!fs.exists(path))                         // check that path exists
-      throw new FileNotFoundException(path.toString());
-
+    // check that path exists
+    fs.getFileStatus(path);
     String qpath = fs.makeQualified(path).toString();
 
     Path trashRoot = fs.getTrashRoot(path);

hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/util/GenericOptionsParser.java

@@ -41,6 +41,7 @@ import org.apache.commons.logging.LogFactory;
 import org.apache.hadoop.classification.InterfaceAudience;
 import org.apache.hadoop.classification.InterfaceStability;
 import org.apache.hadoop.conf.Configuration;
+import org.apache.hadoop.fs.FileStatus;
 import org.apache.hadoop.fs.FileSystem;
 import org.apache.hadoop.fs.FileUtil;
 import org.apache.hadoop.fs.Path;
@@ -328,9 +329,7 @@ public class GenericOptionsParser {
       // check if the local file exists
       FileSystem localFs = FileSystem.getLocal(conf);
       Path p = localFs.makeQualified(new Path(fileName));
-      if (!localFs.exists(p)) {
-          throw new FileNotFoundException("File "+fileName+" does not exist.");
-      }
+      localFs.getFileStatus(p);
       if(LOG.isDebugEnabled()) {
         LOG.debug("setting conf tokensFile: " + fileName);
       }
@@ -437,9 +436,7 @@ public class GenericOptionsParser {
       if (pathURI.getScheme() == null) {
         //default to the local file system
         //check if the file exists or not first
-        if (!localFs.exists(path)) {
-          throw new FileNotFoundException("File " + tmp + " does not exist.");
-        }
+        localFs.getFileStatus(path);
         if (isWildcard) {
           expandWildcard(finalPaths, path, localFs);
         } else {
@@ -452,9 +449,8 @@ public class GenericOptionsParser {
         // these files to the file system ResourceManager is running
         // on.
         FileSystem fs = path.getFileSystem(conf);
-        if (!fs.exists(path)) {
-          throw new FileNotFoundException("File " + tmp + " does not exist.");
-        }
+        // existence check
+        fs.getFileStatus(path);
         if (isWildcard) {
           expandWildcard(finalPaths, path, fs);
         } else {
@@ -476,7 +472,8 @@ public class GenericOptionsParser {
 
   private void expandWildcard(List<String> finalPaths, Path path, FileSystem fs)
       throws IOException {
-    if (!fs.isDirectory(path)) {
+    FileStatus status = fs.getFileStatus(path);
+    if (!status.isDirectory()) {
       throw new FileNotFoundException(path + " is not a directory.");
     }
     // get all the jars in the directory

hadoop-hdfs-project/hadoop-hdfs-client/src/main/java/org/apache/hadoop/hdfs/DistributedFileSystem.java

@@ -2526,8 +2526,9 @@ public class DistributedFileSystem extends FileSystem {
         } else {
           Path userTrash = new Path(ezTrashRoot, System.getProperty(
               "user.name"));
-          if (exists(userTrash)) {
+          try {
             ret.add(getFileStatus(userTrash));
+          } catch (FileNotFoundException ignored) {
           }
         }
       }

hadoop-hdfs-project/hadoop-hdfs-client/src/main/java/org/apache/hadoop/hdfs/client/HdfsAdmin.java

@@ -29,6 +29,7 @@ import org.apache.hadoop.classification.InterfaceStability;
 import org.apache.hadoop.conf.Configuration;
 import org.apache.hadoop.fs.BlockStoragePolicySpi;
 import org.apache.hadoop.fs.CacheFlag;
+import org.apache.hadoop.fs.FileAlreadyExistsException;
 import org.apache.hadoop.fs.FileEncryptionInfo;
 import org.apache.hadoop.fs.FileStatus;
 import org.apache.hadoop.fs.FileSystem;
@@ -476,10 +477,10 @@ public class HdfsAdmin {
 
     Path trashPath = new Path(ez.getPath(), FileSystem.TRASH_PREFIX);
 
-    if (dfs.exists(trashPath)) {
+    try {
+      FileStatus trashFileStatus = dfs.getFileStatus(trashPath);
       String errMessage = "Will not provision new trash directory for " +
           "encryption zone " + ez.getPath() + ". Path already exists.";
-      FileStatus trashFileStatus = dfs.getFileStatus(trashPath);
       if (!trashFileStatus.isDirectory()) {
         errMessage += "\r\n" +
             "Warning: " + trashPath.toString() + " is not a directory";
@@ -489,7 +490,9 @@ public class HdfsAdmin {
             "Warning: the permission of " +
             trashPath.toString() + " is not " + TRASH_PERMISSION;
       }
-      throw new IOException(errMessage);
+      throw new FileAlreadyExistsException(errMessage);
+    } catch (FileNotFoundException ignored) {
+      // no trash path
     }
 
     // Update the permission bits

hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-app/src/main/java/org/apache/hadoop/mapreduce/jobhistory/JobHistoryEventHandler.java

@@ -1374,9 +1374,7 @@ public class JobHistoryEventHandler extends AbstractService
     if (stagingDirFS.exists(fromPath)) {
       LOG.info("Copying " + fromPath.toString() + " to " + toPath.toString());
       // TODO temporarily removing the existing dst
-      if (doneDirFS.exists(toPath)) {
-        doneDirFS.delete(toPath, true);
-      }
+      doneDirFS.delete(toPath, true);
       boolean copied = FileUtil.copy(stagingDirFS, fromPath, doneDirFS, toPath,
           false, getConfig());
 
@@ -1389,10 +1387,6 @@ public class JobHistoryEventHandler extends AbstractService
     }
   }
 
-  boolean pathExists(FileSystem fileSys, Path path) throws IOException {
-    return fileSys.exists(path);
-  }
-
   private String getTempFileName(String srcFile) {
     return srcFile + "_tmp";
   }

hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-core/src/main/java/org/apache/hadoop/mapreduce/JobResourceUploader.java

@@ -435,9 +435,11 @@ class JobResourceUploader {
     LOG.debug("default FileSystem: " + jtFs.getUri());
     FsPermission mapredSysPerms =
         new FsPermission(JobSubmissionFiles.JOB_DIR_PERMISSION);
-    if (!jtFs.exists(submitJobDir)) {
+    try {
+      jtFs.getFileStatus(submitJobDir);
+    } catch (FileNotFoundException e) {
       throw new IOException("Cannot find job submission directory! "
-          + "It should just be created, so something wrong here.");
+          + "It should just be created, so something wrong here.", e);
     }
 
     Path fileDir = JobSubmissionFiles.getJobLog4jFile(submitJobDir);
@@ -488,9 +490,7 @@ class JobResourceUploader {
     if (pathURI.getScheme() == null) {
       // default to the local file system
       // check if the file exists or not first
-      if (!localFs.exists(path)) {
-        throw new FileNotFoundException("File " + file + " does not exist.");
-      }
+      localFs.getFileStatus(path);
       finalPath =
           path.makeQualified(localFs.getUri(), localFs.getWorkingDirectory())
               .toString();
@@ -500,9 +500,7 @@ class JobResourceUploader {
       // these files to the file system ResourceManager is running
       // on.
       FileSystem fs = path.getFileSystem(conf);
-      if (!fs.exists(path)) {
-        throw new FileNotFoundException("File " + file + " does not exist.");
-      }
+      fs.getFileStatus(path);
       finalPath =
           path.makeQualified(fs.getUri(), fs.getWorkingDirectory()).toString();
     }

hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-core/src/main/java/org/apache/hadoop/mapreduce/JobSubmissionFiles.java

@@ -18,6 +18,7 @@
 
 package org.apache.hadoop.mapreduce;
 
+import java.io.FileNotFoundException;
 import java.io.IOException;
 
 import com.google.common.annotations.VisibleForTesting;
@@ -130,7 +131,7 @@ public class JobSubmissionFiles {
     Path stagingArea = cluster.getStagingAreaDir();
     FileSystem fs = stagingArea.getFileSystem(conf);
     UserGroupInformation currentUser = realUser.getCurrentUser();
-    if (fs.exists(stagingArea)) {
+    try {
       FileStatus fsStatus = fs.getFileStatus(stagingArea);
       String fileOwner = fsStatus.getOwner();
       if (!(fileOwner.equals(currentUser.getShortUserName()) || fileOwner
@@ -156,7 +157,7 @@ public class JobSubmissionFiles {
             "to correct value " + JOB_DIR_PERMISSION);
         fs.setPermission(stagingArea, JOB_DIR_PERMISSION);
       }
-    } else {
+    } catch (FileNotFoundException e) {
       fs.mkdirs(stagingArea, new FsPermission(JOB_DIR_PERMISSION));
     }
     return stagingArea;

hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-core/src/main/java/org/apache/hadoop/mapreduce/lib/output/FileOutputCommitter.java

@@ -674,10 +674,9 @@ public class FileOutputCommitter extends OutputCommitter {
       if (algorithmVersion == 1) {
         if (fs.exists(previousCommittedTaskPath)) {
           Path committedTaskPath = getCommittedTaskPath(context);
-          if (fs.exists(committedTaskPath)) {
-            if (!fs.delete(committedTaskPath, true)) {
-              throw new IOException("Could not delete "+committedTaskPath);
-            }
+          if (!fs.delete(committedTaskPath, true) &&
+              fs.exists(committedTaskPath)) {
+            throw new IOException("Could not delete " + committedTaskPath);
           }
           //Rename can fail if the parent directory does not yet exist.
           Path committedParent = committedTaskPath.getParent();
@@ -693,11 +692,12 @@ public class FileOutputCommitter extends OutputCommitter {
         // essentially a no-op, but for backwards compatibility
         // after upgrade to the new fileOutputCommitter,
         // check if there are any output left in committedTaskPath
-        if (fs.exists(previousCommittedTaskPath)) {
+        try {
+          FileStatus from = fs.getFileStatus(previousCommittedTaskPath);
           LOG.info("Recovering task for upgrading scenario, moving files from "
               + previousCommittedTaskPath + " to " + outputPath);
-          FileStatus from = fs.getFileStatus(previousCommittedTaskPath);
           mergePaths(fs, from, outputPath);
+        } catch (FileNotFoundException ignored) {
         }
         LOG.info("Done recovering task " + attemptId);
       }

hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-core/src/main/java/org/apache/hadoop/mapreduce/lib/output/PartialFileOutputCommitter.java

@@ -97,7 +97,7 @@ public class PartialFileOutputCommitter
     for (int i = 0; i < taid.getId(); ++i) {
       TaskAttemptID oldId = new TaskAttemptID(tid, i);
       Path pTask = new Path(pCommit, oldId.toString());
-      if (fs.exists(pTask) && !fs.delete(pTask, true)) {
+      if (!fs.delete(pTask, true) && fs.exists(pTask)) {
         throw new IOException("Failed to delete " + pTask);
       }
     }

hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-core/src/main/java/org/apache/hadoop/mapreduce/lib/partition/InputSampler.java

@@ -322,10 +322,8 @@ public class InputSampler<K,V> extends Configured implements Tool  {
     Arrays.sort(samples, comparator);
     Path dst = new Path(TotalOrderPartitioner.getPartitionFile(conf));
     FileSystem fs = dst.getFileSystem(conf);
-    if (fs.exists(dst)) {
-      fs.delete(dst, false);
-    }
-    SequenceFile.Writer writer = SequenceFile.createWriter(fs, 
+    fs.delete(dst, false);
+    SequenceFile.Writer writer = SequenceFile.createWriter(fs,
       conf, dst, job.getMapOutputKeyClass(), NullWritable.class);
     NullWritable nullValue = NullWritable.get();
     float stepSize = samples.length / (float) numPartitions;

hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-core/src/test/java/org/apache/hadoop/mapreduce/lib/output/TestPreemptableFileOutputCommitter.java

@@ -80,7 +80,7 @@ public class TestPreemptableFileOutputCommitter {
     foc.cleanUpPartialOutputForTask(context);
     verify(fs).delete(eq(p0), eq(true));
     verify(fs).delete(eq(p1), eq(true));
-    verify(fs, never()).delete(eq(p3), eq(true));
+    verify(fs, times(1)).delete(eq(p3), eq(true));
     verify(fs, never()).delete(eq(p2), eq(true));
   }
 

hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-hs/src/main/java/org/apache/hadoop/mapreduce/v2/hs/HistoryServerFileSystemStateStoreService.java

@@ -182,7 +182,7 @@ public class HistoryServerFileSystemStateStoreService
     Path keyPath = new Path(tokenKeysStatePath,
         TOKEN_MASTER_KEY_FILE_PREFIX + key.getKeyId());
     if (fs.exists(keyPath)) {
-      throw new IOException(keyPath + " already exists");
+      throw new FileAlreadyExistsException(keyPath + " already exists");
     }
 
     ByteArrayOutputStream memStream = new ByteArrayOutputStream();

hadoop-mapreduce-project/hadoop-mapreduce-examples/src/main/java/org/apache/hadoop/examples/terasort/TeraOutputFormat.java

@@ -18,6 +18,7 @@
 
 package org.apache.hadoop.examples.terasort;
 
+import java.io.FileNotFoundException;
 import java.io.IOException;
 
 import org.apache.hadoop.conf.Configuration;
@@ -100,7 +101,7 @@ public class TeraOutputFormat extends FileOutputFormat<Text,Text> {
 
     final FileSystem fs = outDir.getFileSystem(jobConf);
 
-    if (fs.exists(outDir)) {
+    try {
       // existing output dir is considered empty iff its only content is the
       // partition file.
       //
@@ -116,6 +117,7 @@ public class TeraOutputFormat extends FileOutputFormat<Text,Text> {
         throw new FileAlreadyExistsException("Output directory " + outDir
             + " already exists");
       }
+    } catch (FileNotFoundException ignored) {
     }
   }
 

hadoop-tools/hadoop-archive-logs/src/main/java/org/apache/hadoop/tools/HadoopArchiveLogs.java

@@ -178,9 +178,7 @@ public class HadoopArchiveLogs implements Tool {
     } finally {
       if (fs != null) {
         // Cleanup working directory
-        if (fs.exists(workingDir)) {
-          fs.delete(workingDir, true);
-        }
+        fs.delete(workingDir, true);
         fs.close();
       }
     }

hadoop-tools/hadoop-archives/src/main/java/org/apache/hadoop/tools/HadoopArchives.java

@@ -20,7 +20,6 @@ package org.apache.hadoop.tools;
 
 import java.io.DataInput;
 import java.io.DataOutput;
-import java.io.FileNotFoundException;
 import java.io.IOException;
 import java.io.UnsupportedEncodingException;
 import java.net.URLEncoder;
@@ -149,9 +148,7 @@ public class HadoopArchives implements Tool {
   IOException {
     for (Path p : paths) {
       FileSystem fs = p.getFileSystem(conf);
-      if (!fs.exists(p)) {
-        throw new FileNotFoundException("Source " + p + " does not exist.");
-      }
+      fs.getFileStatus(p);
     }
   }
 
@@ -619,9 +616,7 @@ public class HadoopArchives implements Tool {
       try {
         destFs = tmpOutput.getFileSystem(conf);
         //this was a stale copy
-        if (destFs.exists(tmpOutput)) {
-          destFs.delete(tmpOutput, false);
-        } 
+        destFs.delete(tmpOutput, false);
         partStream = destFs.create(tmpOutput, false, conf.getInt("io.file.buffer.size", 4096), 
             destFs.getDefaultReplication(tmpOutput), blockSize);
       } catch(IOException ie) {
@@ -747,12 +742,8 @@ public class HadoopArchives implements Tool {
       replication = conf.getInt(HAR_REPLICATION_LABEL, 3);
       try {
         fs = masterIndex.getFileSystem(conf);
-        if (fs.exists(masterIndex)) {
-          fs.delete(masterIndex, false);
-        }
-        if (fs.exists(index)) {
-          fs.delete(index, false);
-        }
+        fs.delete(masterIndex, false);
+        fs.delete(index, false);
         indexStream = fs.create(index);
         outStream = fs.create(masterIndex);
         String version = VERSION + " \n";

hadoop-tools/hadoop-azure/src/main/java/org/apache/hadoop/fs/azure/WasbFsck.java

@@ -18,6 +18,7 @@
 
 package org.apache.hadoop.fs.azure;
 
+import java.io.FileNotFoundException;
 import java.io.IOException;
 import java.util.Arrays;
 import java.util.List;
@@ -139,12 +140,15 @@ public class WasbFsck extends Configured implements Tool {
     if (p == null) {
       return true;
     }
-    if (!fs.exists(p)) {
+    FileStatus status;
+    try {
+      status = fs.getFileStatus(p);
+    } catch (FileNotFoundException e) {
       System.out.println("Path " + p + " does not exist!");
       return true;
     }
 
-    if (fs.isFile(p)) {
+    if (status.isFile()) {
       if (containsColon(p)) {
         System.out.println("Warning: file " + p + " has a colon in its name.");
         return false;

hadoop-tools/hadoop-distcp/src/main/java/org/apache/hadoop/tools/DistCpSync.java

@@ -328,9 +328,7 @@ class DistCpSync {
     Arrays.sort(diffs, DiffInfo.targetComparator);
     for (DiffInfo diff : diffs) {
       if (diff.getTarget() != null) {
-        if (!targetFs.exists(diff.getTarget().getParent())) {
-          targetFs.mkdirs(diff.getTarget().getParent());
-        }
+        targetFs.mkdirs(diff.getTarget().getParent());
         targetFs.rename(diff.getTmp(), diff.getTarget());
       }
     }

hadoop-tools/hadoop-distcp/src/main/java/org/apache/hadoop/tools/SimpleCopyListing.java

@@ -126,7 +126,13 @@ public class SimpleCopyListing extends CopyListing {
 
     Path targetPath = options.getTargetPath();
     FileSystem targetFS = targetPath.getFileSystem(getConf());
-    boolean targetIsFile = targetFS.isFile(targetPath);
+    boolean targetExists = false;
+    boolean targetIsFile = false;
+    try {
+      targetIsFile = targetFS.getFileStatus(targetPath).isFile();
+      targetExists = true;
+    } catch (FileNotFoundException ignored) {
+    }
     targetPath = targetFS.makeQualified(targetPath);
     final boolean targetIsReservedRaw =
         Path.getPathWithoutSchemeAndAuthority(targetPath).toString().
@@ -147,7 +153,7 @@ public class SimpleCopyListing extends CopyListing {
       }
     }
 
-    if (options.shouldAtomicCommit() && targetFS.exists(targetPath)) {
+    if (options.shouldAtomicCommit() && targetExists) {
       throw new InvalidInputException("Target path for atomic-commit already exists: " +
         targetPath + ". Cannot atomic-commit to pre-existing target-path.");
     }
@@ -448,7 +454,7 @@ public class SimpleCopyListing extends CopyListing {
                                                 && !sourceStatus.isDirectory();
 
     if (solitaryFile) {
-      if (targetFS.isFile(target) || !targetPathExists) {
+      if (!targetPathExists || targetFS.isFile(target)) {
         return sourceStatus.getPath();
       } else {
         return sourceStatus.getPath().getParent();
@@ -495,9 +501,7 @@ public class SimpleCopyListing extends CopyListing {
 
   private SequenceFile.Writer getWriter(Path pathToListFile) throws IOException {
     FileSystem fs = pathToListFile.getFileSystem(getConf());
-    if (fs.exists(pathToListFile)) {
-      fs.delete(pathToListFile, false);
-    }
+    fs.delete(pathToListFile, false);
     return SequenceFile.createWriter(getConf(),
             SequenceFile.Writer.file(pathToListFile),
             SequenceFile.Writer.keyClass(Text.class),

hadoop-tools/hadoop-distcp/src/main/java/org/apache/hadoop/tools/mapred/CopyCommitter.java

@@ -279,8 +279,8 @@ public class CopyCommitter extends FileOutputCommitter {
         if (srcAvailable && trgtRelPath.equals(srcRelPath)) continue;
 
         // Target doesn't exist at source. Delete.
-        boolean result = (!targetFS.exists(trgtFileStatus.getPath()) ||
-            targetFS.delete(trgtFileStatus.getPath(), true));
+        boolean result = targetFS.delete(trgtFileStatus.getPath(), true)
+            || !targetFS.exists(trgtFileStatus.getPath());
         if (result) {
           LOG.info("Deleted " + trgtFileStatus.getPath() + " - Missing at source");
           deletedEntries++;

hadoop-tools/hadoop-distcp/src/main/java/org/apache/hadoop/tools/mapred/CopyMapper.java

@@ -113,8 +113,9 @@ public class CopyMapper extends Mapper<Text, CopyListingFileStatus, Text, Text>
             DistCpConstants.CONF_LABEL_TARGET_FINAL_PATH));
     targetFS = targetFinalPath.getFileSystem(conf);
 
-    if (targetFS.exists(targetFinalPath) && targetFS.isFile(targetFinalPath)) {
-      overWrite = true; // When target is an existing file, overwrite it.
+    try {
+      overWrite = overWrite || targetFS.getFileStatus(targetFinalPath).isFile();
+    } catch (FileNotFoundException ignored) {
     }
 
     if (conf.get(DistCpConstants.CONF_LABEL_SSL_CONF) != null) {

hadoop-tools/hadoop-distcp/src/main/java/org/apache/hadoop/tools/mapred/RetriableFileCopyCommand.java

@@ -140,7 +140,7 @@ public class RetriableFileCopyCommand extends RetriableCommand {
       // note that for append case, it is possible that we append partial data
       // and then fail. In that case, for the next retry, we either reuse the
       // partial appended data if it is good or we overwrite the whole file
-      if (!toAppend && targetFS.exists(targetPath)) {
+      if (!toAppend) {
         targetFS.delete(targetPath, false);
       }
     }

hadoop-tools/hadoop-distcp/src/main/java/org/apache/hadoop/tools/util/DistCpUtils.java

@@ -356,9 +356,7 @@ public class DistCpUtils {
       CopyListingFileStatus.class, conf);
     Path output = new Path(sourceListing.toString() +  "_sorted");
 
-    if (fs.exists(output)) {
-      fs.delete(output, false);
-    }
+    fs.delete(output, false);
 
     sorter.sort(sourceListing, output);
     return output;

hadoop-tools/hadoop-extras/src/main/java/org/apache/hadoop/tools/DistTool.java

@@ -20,7 +20,6 @@ package org.apache.hadoop.tools;
 import java.io.BufferedReader;
 import java.io.DataInput;
 import java.io.DataOutput;
-import java.io.FileNotFoundException;
 import java.io.IOException;
 import java.io.InputStreamReader;
 import java.nio.charset.Charset;
@@ -68,11 +67,10 @@ abstract class DistTool implements org.apache.hadoop.util.Tool {
     List<IOException> ioes = new ArrayList<IOException>();
     for(Path p : srcs) {
       try {
-        if (!p.getFileSystem(conf).exists(p)) {
-          ioes.add(new FileNotFoundException("Source "+p+" does not exist."));
-        }
+        p.getFileSystem(conf).getFileStatus(p);
+      } catch(IOException e) {
+        ioes.add(e);
       }
-      catch(IOException e) {ioes.add(e);}
     }
     if (!ioes.isEmpty()) {
       throw new InvalidInputException(ioes);
@@ -113,4 +111,4 @@ abstract class DistTool implements org.apache.hadoop.util.Tool {
     public static final int ERROR_CODE = -2;
     DuplicationException(String message) {super(message);}
   }
-}
+}

hadoop-tools/hadoop-openstack/src/main/java/org/apache/hadoop/fs/swift/util/SwiftTestUtils.java

@@ -489,10 +489,13 @@ public class SwiftTestUtils extends org.junit.Assert {
    */
   public static void assertPathExists(FileSystem fileSystem, String message,
                                Path path) throws IOException {
-    if (!fileSystem.exists(path)) {
+    try {
+      fileSystem.getFileStatus(path);
+    } catch (FileNotFoundException e) {
       //failure, report it
-      fail(message + ": not found " + path + " in " + path.getParent());
-           ls(fileSystem, path.getParent());
+      throw (IOException)new FileNotFoundException(message + ": not found "
+          + path + " in " + path.getParent() + ": " + e + " -- "
+           + ls(fileSystem, path.getParent())).initCause(e);
     }
   }
 

hadoop-tools/hadoop-rumen/src/main/java/org/apache/hadoop/tools/rumen/state/StatePool.java

@@ -21,6 +21,7 @@ import java.io.DataInput;
 import java.io.DataInputStream;
 import java.io.DataOutput;
 import java.io.DataOutputStream;
+import java.io.FileNotFoundException;
 import java.io.IOException;
 import java.text.DateFormat;
 import java.text.SimpleDateFormat;
@@ -186,27 +187,23 @@ public class StatePool {
     if (reload) {
       // Reload persisted entries
       Path stateFilename = new Path(persistDirPath, COMMIT_STATE_FILENAME);
-      FileSystem fs = stateFilename.getFileSystem(conf);
-      if (fs.exists(stateFilename)) {
-        reloadState(stateFilename, conf);
-      } else {
-        throw new RuntimeException("No latest state persist directory found!" 
+      if (!reloadState(stateFilename, conf)) {
+        throw new RuntimeException("No latest state persist directory found!"
                                    + " Disable persistence and run.");
       }
     }
   }
   
-  private void reloadState(Path stateFile, Configuration conf) 
-  throws Exception {
-    FileSystem fs = stateFile.getFileSystem(conf);
-    if (fs.exists(stateFile)) {
+  private boolean reloadState(Path stateFile, Configuration configuration)
+      throws Exception {
+    FileSystem fs = stateFile.getFileSystem(configuration);
+    try (FSDataInputStream in = fs.open(stateFile)) {
       System.out.println("Reading state from " + stateFile.toString());
-      FSDataInputStream in = fs.open(stateFile);
-      
       read(in);
-      in.close();
-    } else {
+      return true;
+    } catch (FileNotFoundException e) {
       System.out.println("No state information found for " + stateFile);
+      return false;
     }
   }
   
@@ -342,4 +339,4 @@ public class StatePool {
     //TODO Should we do a clone?
     this.pool = states;
   }
-}
+}

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-common/src/main/java/org/apache/hadoop/yarn/FileSystemBasedConfigurationProvider.java

@@ -74,9 +74,7 @@ public class FileSystemBasedConfigurationProvider
         new Path(bootstrapConf.get(YarnConfiguration.FS_BASED_RM_CONF_STORE,
             YarnConfiguration.DEFAULT_FS_BASED_RM_CONF_STORE));
     fs = configDir.getFileSystem(bootstrapConf);
-    if (!fs.exists(configDir)) {
-      fs.mkdirs(configDir);
-    }
+    fs.mkdirs(configDir);
   }
 
   @Override

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-common/src/main/java/org/apache/hadoop/yarn/client/api/impl/FileSystemTimelineWriter.java

@@ -19,7 +19,6 @@
 package org.apache.hadoop.yarn.client.api.impl;
 
 import java.io.Closeable;
-import java.io.FileNotFoundException;
 import java.io.Flushable;
 import java.io.IOException;
 import java.net.URI;
@@ -121,10 +120,8 @@ public class FileSystemTimelineWriter extends TimelineWriter{
           .TIMELINE_SERVICE_ENTITYGROUP_FS_STORE_ACTIVE_DIR_DEFAULT));
     fs = FileSystem.newInstance(activePath.toUri(), fsConf);
 
-    if (!fs.exists(activePath)) {
-      throw new FileNotFoundException(activePath + " does not exist");
-    }
-
+    // raise FileNotFoundException if the path is not found
+    fs.getFileStatus(activePath);
     summaryEntityTypes = new HashSet<String>(
         conf.getStringCollection(YarnConfiguration
             .TIMELINE_SERVICE_ENTITYGROUP_FS_STORE_SUMMARY_ENTITY_TYPES));
@@ -992,9 +989,8 @@ public class FileSystemTimelineWriter extends TimelineWriter{
       Path appDir = createApplicationDir(appAttemptId.getApplicationId());
 
       Path attemptDir = new Path(appDir, appAttemptId.toString());
-      if (!fs.exists(attemptDir)) {
-        FileSystem.mkdirs(fs, attemptDir, new FsPermission(
-            APP_LOG_DIR_PERMISSIONS));
+      if (FileSystem.mkdirs(fs, attemptDir,
+          new FsPermission(APP_LOG_DIR_PERMISSIONS))) {
         if (LOG.isDebugEnabled()) {
           LOG.debug("New attempt directory created - " + attemptDir);
         }
@@ -1005,9 +1001,8 @@ public class FileSystemTimelineWriter extends TimelineWriter{
     private Path createApplicationDir(ApplicationId appId) throws IOException {
       Path appDir =
           new Path(activePath, appId.toString());
-      if (!fs.exists(appDir)) {
-        FileSystem.mkdirs(fs, appDir,
-            new FsPermission(APP_LOG_DIR_PERMISSIONS));
+      if (FileSystem.mkdirs(fs, appDir,
+          new FsPermission(APP_LOG_DIR_PERMISSIONS))) {
         if (LOG.isDebugEnabled()) {
           LOG.debug("New app directory created - " + appDir);
         }

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-common/src/main/java/org/apache/hadoop/yarn/nodelabels/FileSystemNodeLabelsStore.java

@@ -19,6 +19,7 @@
 package org.apache.hadoop.yarn.nodelabels;
 
 import java.io.EOFException;
+import java.io.FileNotFoundException;
 import java.io.IOException;
 import java.util.Collection;
 import java.util.List;
@@ -83,9 +84,7 @@ public class FileSystemNodeLabelsStore extends NodeLabelsStore {
     setFileSystem(conf);
 
     // mkdir of root dir path
-    if (!fs.exists(fsWorkingPath)) {
-      fs.mkdirs(fsWorkingPath);
-    }
+    fs.mkdirs(fsWorkingPath);
   }
 
   @Override
@@ -160,12 +159,15 @@ public class FileSystemNodeLabelsStore extends NodeLabelsStore {
       throws IOException {
     // If mirror.new exists, read from mirror.new,
     FSDataInputStream is = null;
-    if (fs.exists(newMirrorPath)) {
+    try {
       is = fs.open(newMirrorPath);
-    } else if (fs.exists(oldMirrorPath)) {
-      is = fs.open(oldMirrorPath);
-    }
+    } catch (FileNotFoundException e) {
+      try {
+        is = fs.open(oldMirrorPath);
+      } catch (FileNotFoundException ignored) {
 
+      }
+    }
     if (null != is) {
       List<NodeLabel> labels = new AddToClusterNodeLabelsRequestPBImpl(
           AddToClusterNodeLabelsRequestProto.parseDelimitedFrom(is))
@@ -209,8 +211,13 @@ public class FileSystemNodeLabelsStore extends NodeLabelsStore {
 
     // Open and process editlog
     editLogPath = new Path(fsWorkingPath, EDITLOG_FILENAME);
-    if (fs.exists(editLogPath)) {
-      FSDataInputStream is = fs.open(editLogPath);
+    FSDataInputStream is;
+    try {
+      is = fs.open(editLogPath);
+    } catch (FileNotFoundException e) {
+      is = null;
+    }
+    if (null != is) {
 
       while (true) {
         try {
@@ -255,6 +262,7 @@ public class FileSystemNodeLabelsStore extends NodeLabelsStore {
           break;
         }
       }
+      is.close();
     }
 
     // Serialize current mirror to mirror.writing

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-common/src/main/java/org/apache/hadoop/yarn/nodelabels/NonAppendableFSNodeLabelStore.java

@@ -116,16 +116,12 @@ public class NonAppendableFSNodeLabelStore extends FileSystemNodeLabelsStore {
       
       // Rename mirror.new.tmp to mirror.new (will remove .new if it's existed)
       Path newPath = new Path(fsWorkingPath, MIRROR_FILENAME + ".new"); 
-      if (fs.exists(newPath)) {
-        fs.delete(newPath, false);
-      }
+      fs.delete(newPath, false);
       fs.rename(newTmpPath, newPath);
       
       // Remove existing mirror and rename mirror.new to mirror
       Path mirrorPath = new Path(fsWorkingPath, MIRROR_FILENAME);
-      if (fs.exists(mirrorPath)) {
-        fs.delete(mirrorPath, false);
-      }
+      fs.delete(mirrorPath, false);
       fs.rename(newPath, mirrorPath);
     } finally {
       readLock.unlock();

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-common/src/test/java/org/apache/hadoop/yarn/nodelabels/TestFileSystemNodeLabelsStore.java

@@ -348,10 +348,10 @@ public class TestFileSystemNodeLabelsStore extends NodeLabelTestBase {
     };
     mockStore.setNodeLabelsManager(mgr);
     mockStore.fs = mockFs;
-    verifyMkdirsCount(mockStore, true, 0);
-    verifyMkdirsCount(mockStore, false, 1);
     verifyMkdirsCount(mockStore, true, 1);
     verifyMkdirsCount(mockStore, false, 2);
+    verifyMkdirsCount(mockStore, true, 3);
+    verifyMkdirsCount(mockStore, false, 4);
   }
 
   private void verifyMkdirsCount(FileSystemNodeLabelsStore store,

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-applicationhistoryservice/src/main/java/org/apache/hadoop/yarn/server/applicationhistoryservice/FileSystemApplicationHistoryStore.java

@@ -22,6 +22,7 @@ import java.io.DataInput;
 import java.io.DataInputStream;
 import java.io.DataOutput;
 import java.io.DataOutputStream;
+import java.io.FileNotFoundException;
 import java.io.IOException;
 import java.util.HashMap;
 import java.util.Map;
@@ -123,12 +124,7 @@ public class FileSystemApplicationHistoryStore extends AbstractService
     rootDirPath = new Path(fsWorkingPath, ROOT_DIR_NAME);
     try {
       fs = getFileSystem(fsWorkingPath, conf);
-
-      if (!fs.isDirectory(rootDirPath)) {
-        fs.mkdirs(rootDirPath);
-        fs.setPermission(rootDirPath, ROOT_DIR_UMASK);
-      }
-
+      fs.mkdirs(rootDirPath, ROOT_DIR_UMASK);
     } catch (IOException e) {
       LOG.error("Error when initializing FileSystemHistoryStorage", e);
       throw e;
@@ -659,9 +655,11 @@ public class FileSystemApplicationHistoryStore extends AbstractService
   private HistoryFileReader getHistoryFileReader(ApplicationId appId)
       throws IOException {
     Path applicationHistoryFile = new Path(rootDirPath, appId.toString());
-    if (!fs.exists(applicationHistoryFile)) {
-      throw new IOException("History file for application " + appId
-          + " is not found");
+    try {
+      fs.getFileStatus(applicationHistoryFile);
+    } catch (FileNotFoundException e) {
+      throw (FileNotFoundException) new FileNotFoundException("History file for"
+          + " application " + appId + " is not found: " + e).initCause(e);
     }
     // The history file is still under writing
     if (outstandingWriters.containsKey(appId)) {

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-applicationhistoryservice/src/test/java/org/apache/hadoop/yarn/server/applicationhistoryservice/TestFileSystemApplicationHistoryStore.java

@@ -27,6 +27,7 @@ import org.junit.Assert;
 import static org.mockito.Mockito.any;
 import static org.mockito.Mockito.doReturn;
 import static org.mockito.Mockito.doThrow;
+import static org.mockito.Mockito.never;
 import static org.mockito.Mockito.spy;
 import static org.mockito.Mockito.times;
 import static org.mockito.Mockito.verify;
@@ -279,8 +280,8 @@ public class TestFileSystemApplicationHistoryStore extends
     }
 
     // Make sure that directory creation was not attempted
-    verify(fs, times(1)).isDirectory(any(Path.class));
-    verify(fs, times(0)).mkdirs(any(Path.class));
+    verify(fs, never()).isDirectory(any(Path.class));
+    verify(fs, times(1)).mkdirs(any(Path.class));
   }
 
   @Test
@@ -301,7 +302,7 @@ public class TestFileSystemApplicationHistoryStore extends
     }
 
     // Make sure that directory creation was attempted
-    verify(fs, times(1)).isDirectory(any(Path.class));
+    verify(fs, never()).isDirectory(any(Path.class));
     verify(fs, times(1)).mkdirs(any(Path.class));
   }
 }

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-nodemanager/src/main/java/org/apache/hadoop/yarn/server/nodemanager/containermanager/localizer/sharedcache/SharedCacheUploader.java

@@ -192,10 +192,12 @@ class SharedCacheUploader implements Callable<Boolean> {
 
   private void deleteTempFile(Path tempPath) {
     try {
-      if (tempPath != null && fs.exists(tempPath)) {
+      if (tempPath != null) {
         fs.delete(tempPath, false);
       }
-    } catch (IOException ignore) {}
+    } catch (IOException ioe) {
+      LOG.debug("Exception received while deleting temp files", ioe);
+    }
   }
 
   /**

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-sharedcachemanager/src/main/java/org/apache/hadoop/yarn/server/sharedcachemanager/store/InMemorySCMStore.java

@@ -18,6 +18,7 @@
 
 package org.apache.hadoop.yarn.server.sharedcachemanager.store;
 
+import java.io.FileNotFoundException;
 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.Collection;
@@ -189,11 +190,14 @@ public class InMemorySCMStore extends SCMStore {
         conf.get(YarnConfiguration.SHARED_CACHE_ROOT,
             YarnConfiguration.DEFAULT_SHARED_CACHE_ROOT);
     Path root = new Path(location);
-    if (!fs.exists(root)) {
+    try {
+      fs.getFileStatus(root);
+    } catch (FileNotFoundException e) {
       String message =
           "The shared cache root directory " + location + " was not found";
       LOG.error(message);
-      throw new IOException(message);
+      throw (IOException)new FileNotFoundException(message)
+          .initCause(e);
     }
 
     int nestedLevel = SharedCacheUtil.getCacheDepth(conf);