Adding FILE_SHARE_DELETE when deleteOnClose is used

cs/src/core/Device/LocalStorageDevice.cs

@@ -182,14 +182,26 @@ private SafeFileHandle CreateHandle(int segmentId)
 
             fileFlags = fileFlags | Native32.FILE_FLAG_NO_BUFFERING;
             if (deleteOnClose)
+            {
                 fileFlags = fileFlags | Native32.FILE_FLAG_DELETE_ON_CLOSE;
 
+                // FILE_SHARE_DELETE allows multiple FASTER instances to share a single log directory and each can specify deleteOnClose.
+                // This will allow the files to persist until all handles across all instances have been closed.
+                fileShare = fileShare | Native32.FILE_SHARE_DELETE;
+            }
+
             var logHandle = Native32.CreateFileW(
                 GetSegmentName(segmentId),
                 fileAccess, fileShare,
                 IntPtr.Zero, fileCreation,
                 fileFlags, IntPtr.Zero);
 
+            if (logHandle.IsInvalid)
+            {
+                var error = Marshal.GetLastWin32Error();
+                throw new IOException($"Error creating log file for {GetSegmentName(segmentId)}, error: {error}", Native32.MakeHRFromErrorCode(error));
+            }
+
             if (preallocateFile)
                 SetFileSize(FileName, logHandle, segmentSize);
 

cs/src/core/Utilities/Native32.cs

@@ -53,6 +53,8 @@ private struct MARK_HANDLE_INFO
         internal const uint FILE_FLAG_DELETE_ON_CLOSE = 0x04000000;
         internal const uint FILE_FLAG_NO_BUFFERING = 0x20000000;
         internal const uint FILE_FLAG_OVERLAPPED = 0x40000000;
+
+        internal const uint FILE_SHARE_DELETE = 0x00000004;
         #endregion
 
         #region io functions
@@ -320,6 +322,11 @@ public static bool SetFileSize(SafeFileHandle file_handle, long file_size)
 
             return true;
         }
+
+        internal static int MakeHRFromErrorCode(int errorCode)
+        {
+            return unchecked(((int)0x80070000) | errorCode);
+        }
         #endregion
     }
 }

cs/test/SharedDirectoryTests.cs

@@ -0,0 +1,232 @@
+// Copyright (c) Microsoft Corporation. All rights reserved.
+// Licensed under the MIT license.
+
+using FASTER.core;
+using NUnit.Framework;
+using NUnit.Framework.Internal;
+using System;
+using System.IO;
+using System.Linq;
+
+namespace FASTER.test.recovery.sumstore
+{
+    [TestFixture]
+    internal class SharedDirectoryTests
+    {
+        const long numUniqueKeys = (1 << 14);
+        const long keySpace = (1L << 14);
+        const long numOps = (1L << 19);
+        const long refreshInterval = (1L << 8);
+        const long completePendingInterval = (1L << 10);
+        private string rootPath;
+        private string sharedLogDirectory;
+        FasterTestInstance original;
+        FasterTestInstance clone;
+
+        [SetUp]
+        public void Setup()
+        {
+            this.rootPath = $"{TestContext.CurrentContext.TestDirectory}\\{Path.GetRandomFileName()}";
+            Directory.CreateDirectory(this.rootPath);
+            this.sharedLogDirectory = $"{this.rootPath}\\SharedLogs";
+            Directory.CreateDirectory(this.sharedLogDirectory);
+
+            this.original = new FasterTestInstance();
+            this.clone = new FasterTestInstance();
+        }
+
+        [TearDown]
+        public void TearDown()
+        {
+            this.original.TearDown();
+            this.clone.TearDown();
+            try
+            {
+                Directory.Delete(this.rootPath, recursive: true);
+            }
+            catch
+            {
+            }
+        }
+
+        [Test]
+        public void SharedLogDirectory()
+        {
+            this.original.Initialize($"{this.rootPath}\\OriginalCheckpoint", this.sharedLogDirectory);
+            this.original.Faster.StartSession();
+            Assert.IsTrue(IsDirectoryEmpty(this.sharedLogDirectory)); // sanity check
+            Populate(this.original.Faster);
+
+            // Take checkpoint from original to start the clone from
+            Assert.IsTrue(this.original.Faster.TakeFullCheckpoint(out var checkpointGuid));
+            Assert.IsTrue(this.original.Faster.CompleteCheckpoint(wait: true));
+
+            // Sanity check against original
+            Assert.IsFalse(IsDirectoryEmpty(this.sharedLogDirectory));
+            Test(this.original, checkpointGuid);
+
+            // Copy checkpoint directory
+            var cloneCheckpointDirectory = $"{this.rootPath}\\CloneCheckpoint";
+            CopyDirectory(new DirectoryInfo(this.original.CheckpointDirectory), new DirectoryInfo(cloneCheckpointDirectory));
+
+            // Recover from original checkpoint
+            this.clone.Initialize(cloneCheckpointDirectory, this.sharedLogDirectory);
+            this.clone.Faster.Recover(checkpointGuid);
+            this.clone.Faster.StartSession();
+
+            // Both sessions should work concurrently
+            Test(this.original, checkpointGuid);
+            Test(this.clone, checkpointGuid);
+
+            // Dispose original, files should not be deleted
+            this.original.TearDown();
+
+            // Clone should still work
+            Assert.IsFalse(IsDirectoryEmpty(this.sharedLogDirectory));
+            Test(this.clone, checkpointGuid);
+
+            this.clone.TearDown();
+
+            // Files should be deleted after both instances are closed
+            Assert.IsTrue(IsDirectoryEmpty(this.sharedLogDirectory));
+        }
+
+        private struct FasterTestInstance
+        {
+            public string CheckpointDirectory { get; private set; }
+            public string LogDirectory { get; private set; }
+            public FasterKV<AdId, NumClicks, Input, Output, Empty, Functions> Faster { get; private set; }
+            public IDevice LogDevice { get; private set; }
+
+            public void Initialize(string checkpointDirectory, string logDirectory)
+            {
+                this.CheckpointDirectory = checkpointDirectory;
+                this.LogDirectory = logDirectory;
+
+                this.LogDevice = Devices.CreateLogDevice($"{this.LogDirectory}\\log", deleteOnClose: true);
+                this.Faster = new FasterKV<AdId, NumClicks, Input, Output, Empty, Functions>(
+                    keySpace,
+                    new Functions(),
+                    new LogSettings { LogDevice = this.LogDevice },
+                    new CheckpointSettings { CheckpointDir = this.CheckpointDirectory, CheckPointType = CheckpointType.FoldOver });
+            }
+
+            public void TearDown()
+            {
+                this.Faster?.StopSession();
+                this.Faster?.Dispose();
+                this.Faster = null;
+                this.LogDevice?.Close();
+                this.LogDevice = null;
+            }
+        }
+
+        private void Populate(FasterKV<AdId, NumClicks, Input, Output, Empty, Functions> fasterInstance)
+        {
+            // Prepare the dataset
+            var inputArray = new Input[numOps];
+            for (int i = 0; i < numOps; i++)
+            {
+                inputArray[i].adId.adId = i % numUniqueKeys;
+                inputArray[i].numClicks.numClicks = 1;
+            }
+
+            // Process the batch of input data
+            for (int i = 0; i < numOps; i++)
+            {
+                fasterInstance.RMW(ref inputArray[i].adId, ref inputArray[i], Empty.Default, i);
+
+                if (i % completePendingInterval == 0)
+                {
+                    fasterInstance.CompletePending(false);
+                }
+                else if (i % refreshInterval == 0)
+                {
+                    fasterInstance.Refresh();
+                }
+            }
+
+            // Make sure operations are completed
+            fasterInstance.CompletePending(true);
+        }
+
+        private void Test(FasterTestInstance fasterInstance, Guid checkpointToken)
+        {
+            var checkpointInfo = default(HybridLogRecoveryInfo);
+            Assert.IsTrue(checkpointInfo.Recover(checkpointToken, new DirectoryConfiguration(fasterInstance.CheckpointDirectory)));
+
+            // Create array for reading
+            var inputArray = new Input[numUniqueKeys];
+            for (int i = 0; i < numUniqueKeys; i++)
+            {
+                inputArray[i].adId.adId = i;
+                inputArray[i].numClicks.numClicks = 0;
+            }
+
+            var input = default(Input);
+            var output = default(Output);
+
+            // Issue read requests
+            for (var i = 0; i < numUniqueKeys; i++)
+            {
+                var status = fasterInstance.Faster.Read(ref inputArray[i].adId, ref input, ref output, Empty.Default, i);
+                Assert.IsTrue(status == Status.OK);
+                inputArray[i].numClicks = output.value;
+            }
+
+            // Complete all pending requests
+            fasterInstance.Faster.CompletePending(true);
+
+
+            // Compute expected array
+            long[] expected = new long[numUniqueKeys];
+            foreach (var guid in checkpointInfo.continueTokens.Keys)
+            {
+                var sno = checkpointInfo.continueTokens[guid];
+                for (long i = 0; i <= sno; i++)
+                {
+                    var id = i % numUniqueKeys;
+                    expected[id]++;
+                }
+            }
+
+            int threadCount = 1; // single threaded test
+            int numCompleted = threadCount - checkpointInfo.continueTokens.Count;
+            for (int t = 0; t < numCompleted; t++)
+            {
+                var sno = numOps;
+                for (long i = 0; i < sno; i++)
+                {
+                    var id = i % numUniqueKeys;
+                    expected[id]++;
+                }
+            }
+
+            // Assert that expected is same as found
+            for (long i = 0; i < numUniqueKeys; i++)
+            {
+                Assert.IsTrue(
+                    expected[i] == inputArray[i].numClicks.numClicks,
+                    "Debug error for AdId {0}: Expected ({1}), Found({2})", inputArray[i].adId.adId, expected[i], inputArray[i].numClicks.numClicks);
+            }
+        }
+
+        private bool IsDirectoryEmpty(string path) => !Directory.Exists(path) || !Directory.EnumerateFileSystemEntries(path).Any();
+
+        private static void CopyDirectory(DirectoryInfo source, DirectoryInfo target)
+        {
+            // Copy each file
+            foreach (var file in source.GetFiles())
+            {
+                file.CopyTo(Path.Combine(target.FullName, file.Name), true);
+            }
+
+            // Copy each subdirectory
+            foreach (var sourceSubDirectory in source.GetDirectories())
+            {
+                var targetSubDirectory = target.CreateSubdirectory(sourceSubDirectory.Name);
+                CopyDirectory(sourceSubDirectory, targetSubDirectory);
+            }
+        }
+    }
+}