Remove custom block device support.

Remove page cache file system.
Remove ability to stream files over page cache.
Always use default file system for all copy/transfer operations.
Remove page file read and write channel.

community/consistency-check/src/main/java/org/neo4j/consistency/ConsistencyCheckService.java

@@ -244,7 +244,7 @@ fileSystem, config, new SimpleLogService( logProvider, logProvider ), pageCache,
             IndexProviderMap indexes = loadIndexProviders( extensions );
 
             LabelScanStore labelScanStore =
-                    new NativeLabelScanStore( pageCache, storeDir, FullStoreChangeStream.EMPTY, true, monitors,
+                    new NativeLabelScanStore( pageCache, storeDir, fileSystem, FullStoreChangeStream.EMPTY, true, monitors,
                             RecoveryCleanupWorkCollector.IGNORE );
             life.add( labelScanStore );
 

community/consistency-check/src/test/java/org/neo4j/consistency/checking/GraphStoreFixture.java

@@ -39,13 +39,13 @@
 import org.neo4j.graphdb.factory.GraphDatabaseBuilder;
 import org.neo4j.graphdb.factory.GraphDatabaseSettings;
 import org.neo4j.index.internal.gbptree.RecoveryCleanupWorkCollector;
+import org.neo4j.internal.kernel.api.exceptions.TransactionFailureException;
 import org.neo4j.io.fs.DefaultFileSystemAbstraction;
 import org.neo4j.io.fs.FileSystemAbstraction;
 import org.neo4j.io.pagecache.PageCache;
 import org.neo4j.io.pagecache.tracing.cursor.context.EmptyVersionContextSupplier;
 import org.neo4j.kernel.api.StatementConstants;
 import org.neo4j.kernel.api.direct.DirectStoreAccess;
-import org.neo4j.internal.kernel.api.exceptions.TransactionFailureException;
 import org.neo4j.kernel.api.labelscan.LabelScanStore;
 import org.neo4j.kernel.configuration.Config;
 import org.neo4j.kernel.extension.KernelExtensions;
@@ -197,7 +197,7 @@ public DirectStoreAccess directStoreAccess()
     private LabelScanStore startLabelScanStore( PageCache pageCache, IndexStoreView indexStoreView, Monitors monitors )
     {
         NativeLabelScanStore labelScanStore =
-                new NativeLabelScanStore( pageCache, directory, new FullLabelStream( indexStoreView ), false, monitors,
+                new NativeLabelScanStore( pageCache, directory, fileSystem, new FullLabelStream( indexStoreView ), false, monitors,
                         RecoveryCleanupWorkCollector.IMMEDIATE );
         try
         {

community/io/src/main/java/org/neo4j/io/pagecache/PageCache.java

@@ -26,8 +26,6 @@
 import java.util.List;
 import java.util.Optional;
 
-import org.neo4j.io.fs.FileSystemAbstraction;
-
 /**
  * A page caching mechanism that allows caching multiple files and accessing their data
  * in pages via a re-usable cursor.
@@ -134,26 +132,9 @@ public interface PageCache extends AutoCloseable
      */
     long maxCachedPages();
 
-    /**
-     * Get the {@link FileSystemAbstraction} that represents the filesystem where the paged files reside.
-     *
-     * @return the filesystem that the page cache is using.
-     */
-    FileSystemAbstraction getCachedFileSystem();
-
     /**
      * Report any thread-local events to the global page cache tracer, as if acquiring a thread-specific page cursor
      * tracer, and reporting the events collected within it.
      */
     void reportEvents();
-
-    /**
-     * Check if the backing {@link FileSystemAbstraction file system} supports regular file operations or not.
-     * <p>
-     * E.g. the file system for block device will not work with generic open and read/write calls and all operations
-     * needs to be done through the page cache.
-     *
-     * @return {@code true} if the backing file system supports regular file operations.
-     */
-    boolean fileSystemSupportsFileOperations();
 }

community/io/src/main/java/org/neo4j/io/pagecache/PageSwapperFactory.java

@@ -45,11 +45,6 @@ public interface PageSwapperFactory
      */
     void open( FileSystemAbstraction fs, Configuration config );
 
-    /**
-     * Get the {@link FileSystemAbstraction} that represents the underlying storage for the page swapper.
-     */
-    FileSystemAbstraction getFileSystemAbstraction();
-
     /**
      * Get the name of this PageSwapperFactory implementation, for configuration purpose.
      */

community/io/src/main/java/org/neo4j/io/pagecache/PagedFile.java

@@ -21,9 +21,6 @@
 
 import java.io.File;
 import java.io.IOException;
-import java.nio.channels.ReadableByteChannel;
-import java.nio.channels.WritableByteChannel;
-import java.nio.file.OpenOption;
 
 /**
  * The representation of a file that has been mapped into the associated page cache.
@@ -191,33 +188,4 @@ public interface PagedFile extends AutoCloseable
     @Override
     void close() throws IOException;
 
-    /**
-     * Open a {@link ReadableByteChannel} view of this PagedFile.
-     * <p>
-     * The channel will read the file sequentially from the beginning till the end.
-     * Seeking is not supported.
-     * <p>
-     * The channel is not thread-safe.
-     *
-     * @return A channel for reading the paged file.
-     */
-    ReadableByteChannel openReadableByteChannel() throws IOException;
-
-    /**
-     * Open a {@link WritableByteChannel} view of this PagedFile.
-     * <p>
-     * The channel will write to the file sequentially from the beginning of the file, overwriting whatever is there
-     * already. If the amount of new data is less than the amount of existing data, then the old data will still be
-     * present at the far end of the file. Thus, this function works neither like opening a file for writing, nor like
-     * appending to a file.
-     * <p>
-     * If this is undesired, then the file can be mapped with {@link java.nio.file.StandardOpenOption#TRUNCATE_EXISTING}
-     * to remove the existing data before writing to the file.
-     * <p>
-     * The channel is not thread-safe.
-     *
-     * @return A channel for writing to the paged file.
-     * @see PageCache#map(File, int, OpenOption...)
-     */
-    WritableByteChannel openWritableByteChannel() throws IOException;
 }

community/io/src/main/java/org/neo4j/io/pagecache/impl/SingleFilePageSwapperFactory.java

@@ -44,12 +44,6 @@ public void open( FileSystemAbstraction fs, Configuration config )
         this.fs = fs;
     }
 
-    @Override
-    public FileSystemAbstraction getFileSystemAbstraction()
-    {
-        return fs;
-    }
-
     @Override
     public PageSwapper createPageSwapper(
             File file,

community/io/src/main/java/org/neo4j/io/pagecache/impl/muninn/MuninnPageCache.java

@@ -35,8 +35,6 @@
 import java.util.concurrent.atomic.AtomicInteger;
 import java.util.concurrent.locks.LockSupport;
 
-import org.neo4j.io.fs.DefaultFileSystemAbstraction;
-import org.neo4j.io.fs.FileSystemAbstraction;
 import org.neo4j.io.mem.MemoryAllocator;
 import org.neo4j.io.pagecache.IOLimiter;
 import org.neo4j.io.pagecache.PageCache;
@@ -700,25 +698,12 @@ public long maxCachedPages()
         return pages.getPageCount();
     }
 
-    @Override
-    public FileSystemAbstraction getCachedFileSystem()
-    {
-        return swapperFactory.getFileSystemAbstraction();
-    }
-
     @Override
     public void reportEvents()
     {
         pageCursorTracerSupplier.get().reportEvents();
     }
 
-    @Override
-    public boolean fileSystemSupportsFileOperations()
-    {
-        // Default filesystem supports direct file access.
-        return getCachedFileSystem() instanceof DefaultFileSystemAbstraction;
-    }
-
     int getPageCacheId()
     {
         return pageCacheId;

community/io/src/main/java/org/neo4j/io/pagecache/impl/muninn/MuninnPagedFile.java

@@ -23,8 +23,6 @@
 import java.io.Flushable;
 import java.io.IOException;
 import java.nio.channels.ClosedChannelException;
-import java.nio.channels.ReadableByteChannel;
-import java.nio.channels.WritableByteChannel;
 import java.util.Arrays;
 
 import org.neo4j.io.pagecache.IOLimiter;
@@ -34,8 +32,6 @@
 import org.neo4j.io.pagecache.PageSwapperFactory;
 import org.neo4j.io.pagecache.PagedFile;
 import org.neo4j.io.pagecache.impl.FileIsNotMappedException;
-import org.neo4j.io.pagecache.impl.PagedReadableByteChannel;
-import org.neo4j.io.pagecache.impl.PagedWritableByteChannel;
 import org.neo4j.io.pagecache.tracing.FlushEvent;
 import org.neo4j.io.pagecache.tracing.FlushEventOpportunity;
 import org.neo4j.io.pagecache.tracing.MajorFlushEvent;
@@ -228,18 +224,6 @@ public void close()
         pageCache.unmap( this );
     }
 
-    @Override
-    public ReadableByteChannel openReadableByteChannel() throws IOException
-    {
-        return new PagedReadableByteChannel( this );
-    }
-
-    @Override
-    public WritableByteChannel openWritableByteChannel() throws IOException
-    {
-        return new PagedWritableByteChannel( this );
-    }
-
     void closeSwapper() throws IOException
     {
         // We don't set closeStackTrace in close(), because the reference count may keep the file open.