[ISSUE #9693] Add writeWithoutMmap configuration to prevent JVM crash when device becomes read-only

store/src/main/java/org/apache/rocketmq/store/AllocateMappedFileService.java

@@ -172,16 +172,17 @@ private boolean mmapOperation() {
                 long beginTime = System.currentTimeMillis();
 
                 MappedFile mappedFile;
+                boolean writeWithoutMmap = messageStore.getMessageStoreConfig().isWriteWithoutMmap();
                 if (messageStore.isTransientStorePoolEnable()) {
                     try {
                         mappedFile = ServiceLoader.load(MappedFile.class).iterator().next();
                         mappedFile.init(req.getFilePath(), req.getFileSize(), messageStore.getTransientStorePool());
                     } catch (RuntimeException e) {
                         log.warn("Use default implementation.");
-                        mappedFile = new DefaultMappedFile(req.getFilePath(), req.getFileSize(), messageStore.getTransientStorePool());
+                        mappedFile = new DefaultMappedFile(req.getFilePath(), req.getFileSize(), messageStore.getTransientStorePool(), writeWithoutMmap);
                     }
                 } else {
-                    mappedFile = new DefaultMappedFile(req.getFilePath(), req.getFileSize());
+                    mappedFile = new DefaultMappedFile(req.getFilePath(), req.getFileSize(), writeWithoutMmap);
                 }
 
                 long elapsedTime = UtilAll.computeElapsedTimeMilliseconds(beginTime);
@@ -195,7 +196,9 @@ private boolean mmapOperation() {
                 if (mappedFile.getFileSize() >= this.messageStore.getMessageStoreConfig()
                     .getMappedFileSizeCommitLog()
                     &&
-                    this.messageStore.getMessageStoreConfig().isWarmMapedFileEnable()) {
+                    this.messageStore.getMessageStoreConfig().isWarmMapedFileEnable()
+                    &&
+                    !this.messageStore.getMessageStoreConfig().isWriteWithoutMmap()) {
                     mappedFile.warmMappedFile(this.messageStore.getMessageStoreConfig().getFlushDiskType(),
                         this.messageStore.getMessageStoreConfig().getFlushLeastPagesWhenWarmMapedFile());
                 }

store/src/main/java/org/apache/rocketmq/store/CommitLog.java

@@ -118,7 +118,8 @@ public CommitLog(final DefaultMessageStore messageStore) {
         } else {
             this.mappedFileQueue = new MappedFileQueue(storePath,
                 messageStore.getMessageStoreConfig().getMappedFileSizeCommitLog(),
-                messageStore.getAllocateMappedFileService());
+                messageStore.getAllocateMappedFileService(),
+                messageStore.getMessageStoreConfig().isWriteWithoutMmap());
         }
 
         this.defaultMessageStore = messageStore;

store/src/main/java/org/apache/rocketmq/store/ConsumeQueue.java

@@ -98,7 +98,12 @@ public ConsumeQueue(final String topic, final int queueId, final String storePat
             + File.separator + topic
             + File.separator + queueId;
 
-        this.mappedFileQueue = new MappedFileQueue(queueDir, mappedFileSize, null);
+        boolean writeWithoutMmap = false;
+        if (messageStore.getMessageStoreConfig() != null) {
+            writeWithoutMmap = messageStore.getMessageStoreConfig().isWriteWithoutMmap();
+        }
+
+        this.mappedFileQueue = new MappedFileQueue(queueDir, mappedFileSize, null, writeWithoutMmap);
 
         this.byteBufferIndex = ByteBuffer.allocate(CQ_STORE_UNIT_SIZE);
 
@@ -108,7 +113,8 @@ public ConsumeQueue(final String topic, final int queueId, final String storePat
                 queueId,
                 StorePathConfigHelper.getStorePathConsumeQueueExt(messageStore.getMessageStoreConfig().getStorePathRootDir()),
                 messageStore.getMessageStoreConfig().getMappedFileSizeConsumeQueueExt(),
-                messageStore.getMessageStoreConfig().getBitMapLengthConsumeQueueExt()
+                messageStore.getMessageStoreConfig().getBitMapLengthConsumeQueueExt(),
+                writeWithoutMmap
             );
         }
     }

store/src/main/java/org/apache/rocketmq/store/ConsumeQueueExt.java

@@ -90,6 +90,42 @@ public ConsumeQueueExt(final String topic,
         }
     }
 
+    /**
+     * Constructor with writeWithoutMmap support.
+     *
+     * @param topic topic
+     * @param queueId id of queue
+     * @param storePath root dir of files to store.
+     * @param mappedFileSize file size
+     * @param bitMapLength bit map length.
+     * @param writeWithoutMmap whether to use RandomAccessFile instead of MappedByteBuffer
+     */
+    public ConsumeQueueExt(final String topic,
+        final int queueId,
+        final String storePath,
+        final int mappedFileSize,
+        final int bitMapLength,
+        final boolean writeWithoutMmap) {
+
+        this.storePath = storePath;
+        this.mappedFileSize = mappedFileSize;
+
+        this.topic = topic;
+        this.queueId = queueId;
+
+        String queueDir = this.storePath
+            + File.separator + topic
+            + File.separator + queueId;
+
+        this.mappedFileQueue = new MappedFileQueue(queueDir, mappedFileSize, null, writeWithoutMmap);
+
+        if (bitMapLength > 0) {
+            this.tempContainer = ByteBuffer.allocate(
+                bitMapLength / Byte.SIZE
+            );
+        }
+    }
+
     public long getTotalSize() {
         return this.mappedFileQueue.getTotalFileSize();
     }

store/src/main/java/org/apache/rocketmq/store/MappedFileQueue.java

@@ -53,6 +53,11 @@ public class MappedFileQueue implements Swappable {
     protected long committedWhere = 0;
 
     protected volatile long storeTimestamp = 0;
+
+    /**
+     * Configuration flag to use RandomAccessFile instead of MappedByteBuffer for writing
+     */
+    protected boolean writeWithoutMmap = false;
 
     public MappedFileQueue(final String storePath, int mappedFileSize,
         AllocateMappedFileService allocateMappedFileService) {
@@ -61,6 +66,14 @@ public MappedFileQueue(final String storePath, int mappedFileSize,
         this.allocateMappedFileService = allocateMappedFileService;
     }
 
+    public MappedFileQueue(final String storePath, int mappedFileSize,
+        AllocateMappedFileService allocateMappedFileService, boolean writeWithoutMmap) {
+        this.storePath = storePath;
+        this.mappedFileSize = mappedFileSize;
+        this.allocateMappedFileService = allocateMappedFileService;
+        this.writeWithoutMmap = writeWithoutMmap;
+    }
+
     public void checkSelf() {
         List<MappedFile> mappedFiles = new ArrayList<>(this.mappedFiles);
         if (!mappedFiles.isEmpty()) {
@@ -266,7 +279,7 @@ public boolean doLoad(List<File> files) {
             }
 
             try {
-                MappedFile mappedFile = new DefaultMappedFile(file.getPath(), mappedFileSize);
+                MappedFile mappedFile = new DefaultMappedFile(file.getPath(), mappedFileSize, writeWithoutMmap);
 
                 mappedFile.setWrotePosition(this.mappedFileSize);
                 mappedFile.setFlushedPosition(this.mappedFileSize);
@@ -356,7 +369,7 @@ protected MappedFile doCreateMappedFile(String nextFilePath, String nextNextFile
                     nextNextFilePath, this.mappedFileSize);
         } else {
             try {
-                mappedFile = new DefaultMappedFile(nextFilePath, this.mappedFileSize);
+                mappedFile = new DefaultMappedFile(nextFilePath, this.mappedFileSize, this.writeWithoutMmap);
             } catch (IOException e) {
                 log.error("create mappedFile exception", e);
             }

store/src/main/java/org/apache/rocketmq/store/MultiPathMappedFileQueue.java

@@ -39,7 +39,8 @@ public class MultiPathMappedFileQueue extends MappedFileQueue {
     public MultiPathMappedFileQueue(MessageStoreConfig messageStoreConfig, int mappedFileSize,
                                     AllocateMappedFileService allocateMappedFileService,
                                     Supplier<Set<String>> fullStorePathsSupplier) {
-        super(messageStoreConfig.getStorePathCommitLog(), mappedFileSize, allocateMappedFileService);
+        super(messageStoreConfig.getStorePathCommitLog(), mappedFileSize, allocateMappedFileService, 
+              messageStoreConfig.isWriteWithoutMmap());
         this.config = messageStoreConfig;
         this.fullStorePathsSupplier = fullStorePathsSupplier;
     }

store/src/main/java/org/apache/rocketmq/store/config/MessageStoreConfig.java

@@ -238,6 +238,13 @@ public class MessageStoreConfig {
     private int transientStorePoolSize = 5;
     private boolean fastFailIfNoBufferInStorePool = false;
 
+    /**
+     * When true, use RandomAccessFile for writing instead of MappedByteBuffer.
+     * This can be useful for certain scenarios where mmap is not desired.
+     */
+    @ImportantField
+    private boolean writeWithoutMmap = false;
+
     // DLedger message store config
     private boolean enableDLegerCommitLog = false;
     private String dLegerGroup;
@@ -1140,6 +1147,14 @@ public void setTransientStorePoolEnable(final boolean transientStorePoolEnable)
         this.transientStorePoolEnable = transientStorePoolEnable;
     }
 
+    public boolean isWriteWithoutMmap() {
+        return writeWithoutMmap;
+    }
+
+    public void setWriteWithoutMmap(final boolean writeWithoutMmap) {
+        this.writeWithoutMmap = writeWithoutMmap;
+    }
+
     public int getTransientStorePoolSize() {
         return transientStorePoolSize;
     }