--- /dev/null	2017-11-09 09:38:01.297999907 +0100
+++ new/src/jdk.jfr/share/classes/jdk/jfr/internal/RepositoryChunk.java	2018-04-09 16:03:47.430000926 +0200
@@ -0,0 +1,210 @@
+/*
+ * Copyright (c) 2012, 2018, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.  Oracle designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Oracle in the LICENSE file that accompanied this code.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+package jdk.jfr.internal;
+
+import java.io.IOException;
+import java.io.RandomAccessFile;
+import java.nio.channels.ReadableByteChannel;
+import java.nio.file.Path;
+import java.time.Instant;
+import java.time.LocalDateTime;
+import java.time.ZonedDateTime;
+import java.util.Comparator;
+import java.util.Objects;
+
+import jdk.jfr.internal.SecuritySupport.SafePath;
+
+final class RepositoryChunk {
+    private static final int MAX_CHUNK_NAMES = 100;
+
+    static final Comparator<RepositoryChunk> END_TIME_COMPARATOR = new Comparator<RepositoryChunk>() {
+        @Override
+        public int compare(RepositoryChunk c1, RepositoryChunk c2) {
+            return c1.endTime.compareTo(c2.endTime);
+        }
+    };
+
+    private final SafePath repositoryPath;
+    private final SafePath unFinishedFile;
+    private final SafePath file;
+    private final Instant startTime;
+    private final RandomAccessFile unFinishedRAF;
+
+    private Instant endTime = null; // unfinished
+    private int refCount = 0;
+    private long size;
+
+    RepositoryChunk(SafePath path, Instant startTime) throws Exception {
+        ZonedDateTime z = ZonedDateTime.now();
+        String fileName = Repository.REPO_DATE_FORMAT.format(
+                LocalDateTime.ofInstant(startTime, z.getZone()));
+        this.startTime = startTime;
+        this.repositoryPath = path;
+        this.unFinishedFile = findFileName(repositoryPath, fileName, ".part");
+        this.file = findFileName(repositoryPath, fileName, ".jfr");
+        this.unFinishedRAF = SecuritySupport.createRandomAccessFile(unFinishedFile);
+        SecuritySupport.touch(file);
+    }
+
+    private static SafePath findFileName(SafePath directory, String name, String extension) throws Exception {
+        Path p = directory.toPath().resolve(name + extension);
+        for (int i = 1; i < MAX_CHUNK_NAMES; i++) {
+            SafePath s = new SafePath(p);
+            if (!SecuritySupport.exists(s)) {
+                return s;
+            }
+            String extendedName = String.format("%s_%02d%s", name, i, extension);
+            p = directory.toPath().resolve(extendedName);
+        }
+        p = directory.toPath().resolve(name + "_" + System.currentTimeMillis() + extension);
+        return SecuritySupport.toRealPath(new SafePath(p));
+    }
+
+    public SafePath getUnfishedFile() {
+        return unFinishedFile;
+    }
+
+    void finish(Instant endTime) {
+        try {
+            finishWithException(endTime);
+        } catch (IOException e) {
+            Logger.log(LogTag.JFR, LogLevel.ERROR, "Could not finish chunk. " + e.getMessage());
+        }
+    }
+
+    private void finishWithException(Instant endTime) throws IOException {
+        unFinishedRAF.close();
+        this.size = finish(unFinishedFile, file);
+        this.endTime = endTime;
+        Logger.log(LogTag.JFR_SYSTEM, LogLevel.DEBUG, () -> "Chunk finished: " + file);
+    }
+
+    private static long finish(SafePath unFinishedFile, SafePath file) throws IOException {
+        Objects.requireNonNull(unFinishedFile);
+        Objects.requireNonNull(file);
+        SecuritySupport.delete(file);
+        SecuritySupport.moveReplace(unFinishedFile, file);
+        return SecuritySupport.getFileSize(file);
+    }
+
+    public Instant getStartTime() {
+        return startTime;
+    }
+
+    public Instant getEndTime() {
+        return endTime;
+    }
+
+    private void delete(SafePath f) {
+        try {
+            SecuritySupport.delete(f);
+            Logger.log(LogTag.JFR, LogLevel.DEBUG, () -> "Repository chunk " + f + " deleted");
+        } catch (IOException e) {
+            Logger.log(LogTag.JFR, LogLevel.ERROR, ()  -> "Repository chunk " + f + " could not be deleted: " + e.getMessage());
+            if (f != null) {
+                SecuritySupport.deleteOnExit(f);
+            }
+        }
+    }
+
+    private void destroy() {
+        if (!isFinished()) {
+            finish(Instant.MIN);
+        }
+        if (file != null) {
+            delete(file);
+        }
+        try {
+            unFinishedRAF.close();
+        } catch (IOException e) {
+            Logger.log(LogTag.JFR, LogLevel.ERROR, () -> "Could not close random access file: " + unFinishedFile.toString() + ". File will not be deleted due to: " + e.getMessage());
+        }
+    }
+
+    public synchronized void use() {
+        ++refCount;
+        Logger.log(LogTag.JFR_SYSTEM, LogLevel.DEBUG, () -> "Use chunk " + toString() + " ref count now " + refCount);
+    }
+
+    public synchronized void release() {
+        --refCount;
+        Logger.log(LogTag.JFR_SYSTEM, LogLevel.DEBUG, () -> "Release chunk " + toString() + " ref count now " + refCount);
+        if (refCount == 0) {
+            destroy();
+        }
+    }
+
+    @Override
+    @SuppressWarnings("deprecation")
+    protected void finalize() {
+        boolean destroy = false;
+        synchronized (this) {
+            if (refCount > 0) {
+                destroy = true;
+            }
+        }
+        if (destroy) {
+            destroy();
+        }
+    }
+
+    public long getSize() {
+        return size;
+    }
+
+    public boolean isFinished() {
+        return endTime != null;
+    }
+
+    @Override
+    public String toString() {
+        if (isFinished()) {
+            return file.toString();
+        }
+        return unFinishedFile.toString();
+    }
+
+    ReadableByteChannel newChannel() throws IOException {
+        if (!isFinished()) {
+            throw new IOException("Chunk not finished");
+        }
+        return ((SecuritySupport.newFileChannelToRead(file)));
+    }
+
+    public boolean inInterval(Instant startTime, Instant endTime) {
+        if (startTime != null && getEndTime().isBefore(startTime)) {
+            return false;
+        }
+        if (endTime != null && getStartTime().isAfter(endTime)) {
+            return false;
+        }
+        return true;
+    }
+
+    public SafePath getFile() {
+        return file;
+    }
+}