sys: IRP_MJ_FLUSH_BUFFERS

inc/winfsp/fsctl.h

@@ -246,6 +246,11 @@ typedef struct
             } Info;
         } SetInformation;
         struct
+        {
+            UINT64 UserContext;
+            UINT64 UserContext2;
+        } FlushBuffers;
+        struct
         {
             UINT32 FsInformationClass;
             union

inc/winfsp/winfsp.h

@@ -72,6 +72,9 @@ typedef struct _FSP_FILE_SYSTEM_INTERFACE
         FSP_FSCTL_TRANSACT_REQ *Request,
         PVOID FileNode, PVOID Buffer, UINT64 Offset, ULONG Length, BOOLEAN WriteToEndOfFile,
         PULONG PBytesTransferred, FSP_FSCTL_FILE_INFO *FileInfo);
+    NTSTATUS (*Flush)(FSP_FILE_SYSTEM *FileSystem,
+        FSP_FSCTL_TRANSACT_REQ *Request,
+        PVOID FileNode);
     NTSTATUS (*GetFileInfo)(FSP_FILE_SYSTEM *FileSystem,
         FSP_FSCTL_TRANSACT_REQ *Request,
         PVOID FileNode,
@@ -196,6 +199,8 @@ FSP_API NTSTATUS FspFileSystemOpQueryInformation(FSP_FILE_SYSTEM *FileSystem,
     FSP_FSCTL_TRANSACT_REQ *Request, FSP_FSCTL_TRANSACT_RSP *Response);
 FSP_API NTSTATUS FspFileSystemOpSetInformation(FSP_FILE_SYSTEM *FileSystem,
     FSP_FSCTL_TRANSACT_REQ *Request, FSP_FSCTL_TRANSACT_RSP *Response);
+FSP_API NTSTATUS FspFileSystemOpFlushBuffers(FSP_FILE_SYSTEM *FileSystem,
+    FSP_FSCTL_TRANSACT_REQ *Request, FSP_FSCTL_TRANSACT_RSP *Response);
 FSP_API NTSTATUS FspFileSystemOpQueryVolumeInformation(FSP_FILE_SYSTEM *FileSystem,
     FSP_FSCTL_TRANSACT_REQ *Request, FSP_FSCTL_TRANSACT_RSP *Response);
 FSP_API NTSTATUS FspFileSystemOpSetVolumeInformation(FSP_FILE_SYSTEM *FileSystem,

src/dll/dispatch.c

@@ -46,14 +46,15 @@ FSP_API NTSTATUS FspFileSystemCreate(PWSTR DevicePath,
     FileSystem->Operations[FspFsctlTransactCloseKind] = FspFileSystemOpClose;
     FileSystem->Operations[FspFsctlTransactReadKind] = FspFileSystemOpRead;
     FileSystem->Operations[FspFsctlTransactWriteKind] = FspFileSystemOpWrite;
-    // !!!: ...
     FileSystem->Operations[FspFsctlTransactQueryInformationKind] = FspFileSystemOpQueryInformation;
     FileSystem->Operations[FspFsctlTransactSetInformationKind] = FspFileSystemOpSetInformation;
+    FileSystem->Operations[FspFsctlTransactFlushBuffersKind] = FspFileSystemOpFlushBuffers;
     FileSystem->Operations[FspFsctlTransactQueryVolumeInformationKind] = FspFileSystemOpQueryVolumeInformation;
     FileSystem->Operations[FspFsctlTransactSetVolumeInformationKind] = FspFileSystemOpSetVolumeInformation;
     FileSystem->Operations[FspFsctlTransactQueryDirectoryKind] = FspFileSystemOpQueryDirectory;
     FileSystem->Operations[FspFsctlTransactQuerySecurityKind] = FspFileSystemOpQuerySecurity;
     FileSystem->Operations[FspFsctlTransactSetSecurityKind] = FspFileSystemOpSetSecurity;
+    // !!!: ...
     FileSystem->Interface = Interface;
 
     *PFileSystem = FileSystem;

src/dll/fsop.c

@@ -463,6 +463,16 @@ FSP_API NTSTATUS FspFileSystemOpWrite(FSP_FILE_SYSTEM *FileSystem,
     return Result;
 }
 
+FSP_API NTSTATUS FspFileSystemOpFlushBuffers(FSP_FILE_SYSTEM *FileSystem,
+    FSP_FSCTL_TRANSACT_REQ *Request, FSP_FSCTL_TRANSACT_RSP *Response)
+{
+    if (0 == FileSystem->Interface->Flush)
+        return STATUS_SUCCESS; /* liar! */
+
+    return FileSystem->Interface->Flush(FileSystem, Request,
+        (PVOID)Request->Req.FlushBuffers.UserContext);
+}
+
 FSP_API NTSTATUS FspFileSystemOpQueryInformation(FSP_FILE_SYSTEM *FileSystem,
     FSP_FSCTL_TRANSACT_REQ *Request, FSP_FSCTL_TRANSACT_RSP *Response)
 {

src/sys/driver.h

@@ -408,6 +408,8 @@ NTSTATUS FspCcMdlReadComplete(PFILE_OBJECT FileObject, PMDL MdlChain);
 NTSTATUS FspCcPrepareMdlWrite(PFILE_OBJECT FileObject, PLARGE_INTEGER FileOffset, ULONG Length,
     PMDL *PMdlChain, PIO_STATUS_BLOCK IoStatus);
 NTSTATUS FspCcMdlWriteComplete(PFILE_OBJECT FileObject, PLARGE_INTEGER FileOffset, PMDL MdlChain);
+NTSTATUS FspCcFlushCache(PSECTION_OBJECT_POINTERS SectionObjectPointer,
+    PLARGE_INTEGER FileOffset, ULONG Length, PIO_STATUS_BLOCK IoStatus);
 NTSTATUS FspQuerySecurityDescriptorInfo(SECURITY_INFORMATION SecurityInformation,
     PSECURITY_DESCRIPTOR SecurityDescriptor, PULONG PLength,
     PSECURITY_DESCRIPTOR ObjectsSecurityDescriptor);

src/sys/flush.c

@@ -9,20 +9,74 @@
 static NTSTATUS FspFsvolFlushBuffers(
     PDEVICE_OBJECT DeviceObject, PIRP Irp, PIO_STACK_LOCATION IrpSp);
 FSP_IOCMPL_DISPATCH FspFsvolFlushBuffersComplete;
+static FSP_IOP_REQUEST_FINI FspFsvolFlushBuffersRequestFini;
 FSP_DRIVER_DISPATCH FspFlushBuffers;
 
 #ifdef ALLOC_PRAGMA
 #pragma alloc_text(PAGE, FspFsvolFlushBuffers)
 #pragma alloc_text(PAGE, FspFsvolFlushBuffersComplete)
+#pragma alloc_text(PAGE, FspFsvolFlushBuffersRequestFini)
 #pragma alloc_text(PAGE, FspFlushBuffers)
 #endif
 
+enum
+{
+    /* FlushBuffers */
+    RequestFileNode                     = 0,
+};
+
 static NTSTATUS FspFsvolFlushBuffers(
     PDEVICE_OBJECT DeviceObject, PIRP Irp, PIO_STACK_LOCATION IrpSp)
 {
     PAGED_CODE();
 
-    return STATUS_INVALID_DEVICE_REQUEST;
+    NTSTATUS Result;
+    FSP_FSCTL_TRANSACT_REQ *Request;
+
+    /* is this a valid FileObject? */
+    if (!FspFileNodeIsValid(IrpSp->FileObject->FsContext))
+    {
+        /* indicate that we are flushing the whole volume! */
+        Result = FspIopCreateRequest(Irp, 0, 0, &Request);
+        if (!NT_SUCCESS(Result))
+            return Result;
+
+        Request->Kind = FspFsctlTransactFlushBuffersKind;
+
+        return FSP_STATUS_IOQ_POST;
+    }
+
+    PFILE_OBJECT FileObject = IrpSp->FileObject;
+    FSP_FILE_NODE *FileNode = FileObject->FsContext;
+    FSP_FILE_DESC *FileDesc = FileObject->FsContext2;
+    IO_STATUS_BLOCK IoStatus;
+
+    ASSERT(FileNode == FileDesc->FileNode);
+
+    FspFileNodeAcquireExclusive(FileNode, Full);
+
+    Result = FspCcFlushCache(FileObject->SectionObjectPointer, 0, 0, &IoStatus);
+    if (!NT_SUCCESS(Result))
+    {
+        FspFileNodeRelease(FileNode, Full);
+        return Result;
+    }
+
+    Result = FspIopCreateRequestEx(Irp, 0, 0, FspFsvolFlushBuffersRequestFini, &Request);
+    if (!NT_SUCCESS(Result))
+    {
+        FspFileNodeRelease(FileNode, Full);
+        return Result;
+    }
+
+    Request->Kind = FspFsctlTransactFlushBuffersKind;
+    Request->Req.FlushBuffers.UserContext = FileNode->UserContext;
+    Request->Req.FlushBuffers.UserContext2 = FileDesc->UserContext2;
+
+    FspFileNodeSetOwner(FileNode, Full, Request);
+    FspIopRequestContext(Request, RequestFileNode) = FileNode;
+
+    return FSP_STATUS_IOQ_POST;
 }
 
 NTSTATUS FspFsvolFlushBuffersComplete(
@@ -30,7 +84,18 @@ NTSTATUS FspFsvolFlushBuffersComplete(
 {
     FSP_ENTER_IOC(PAGED_CODE());
 
-    FSP_LEAVE_IOC("%s", "");
+    FSP_LEAVE_IOC("FileObject=%p",
+        IrpSp->FileObject);
+}
+
+static VOID FspFsvolFlushBuffersRequestFini(FSP_FSCTL_TRANSACT_REQ *Request, PVOID Context[4])
+{
+    PAGED_CODE();
+
+    FSP_FILE_NODE *FileNode = Context[RequestFileNode];
+
+    if (0 != FileNode)
+        FspFileNodeReleaseOwner(FileNode, Full, Request);
 }
 
 NTSTATUS FspFlushBuffers(
@@ -46,5 +111,6 @@ NTSTATUS FspFlushBuffers(
         FSP_RETURN(Result = STATUS_INVALID_DEVICE_REQUEST);
     }
 
-    FSP_LEAVE_MJ("%s", "");
+    FSP_LEAVE_MJ("FileObject=%p",
+        IrpSp->FileObject);
 }

src/sys/util.c

@@ -29,6 +29,8 @@ NTSTATUS FspCcMdlReadComplete(PFILE_OBJECT FileObject, PMDL MdlChain);
 NTSTATUS FspCcPrepareMdlWrite(PFILE_OBJECT FileObject, PLARGE_INTEGER FileOffset, ULONG Length,
     PMDL *PMdlChain, PIO_STATUS_BLOCK IoStatus);
 NTSTATUS FspCcMdlWriteComplete(PFILE_OBJECT FileObject, PLARGE_INTEGER FileOffset, PMDL MdlChain);
+NTSTATUS FspCcFlushCache(PSECTION_OBJECT_POINTERS SectionObjectPointer,
+    PLARGE_INTEGER FileOffset, ULONG Length, PIO_STATUS_BLOCK IoStatus);
 NTSTATUS FspQuerySecurityDescriptorInfo(SECURITY_INFORMATION SecurityInformation,
     PSECURITY_DESCRIPTOR SecurityDescriptor, PULONG PLength,
     PSECURITY_DESCRIPTOR ObjectsSecurityDescriptor);
@@ -83,6 +85,7 @@ VOID FspSafeMdlDelete(FSP_SAFE_MDL *SafeMdl);
 #pragma alloc_text(PAGE, FspCcMdlReadComplete)
 #pragma alloc_text(PAGE, FspCcPrepareMdlWrite)
 #pragma alloc_text(PAGE, FspCcMdlWriteComplete)
+#pragma alloc_text(PAGE, FspCcFlushCache)
 #pragma alloc_text(PAGE, FspQuerySecurityDescriptorInfo)
 #pragma alloc_text(PAGE, FspNotifyInitializeSync)
 #pragma alloc_text(PAGE, FspNotifyFullChangeDirectory)
@@ -528,6 +531,29 @@ NTSTATUS FspCcMdlWriteComplete(PFILE_OBJECT FileObject, PLARGE_INTEGER FileOffse
     }
 }
 
+NTSTATUS FspCcFlushCache(PSECTION_OBJECT_POINTERS SectionObjectPointer,
+    PLARGE_INTEGER FileOffset, ULONG Length, PIO_STATUS_BLOCK IoStatus)
+{
+    PAGED_CODE();
+
+    NTSTATUS Result;
+
+    try
+    {
+        CcFlushCache(SectionObjectPointer, FileOffset, Length, IoStatus);
+        Result = IoStatus->Status;
+    }
+    except (EXCEPTION_EXECUTE_HANDLER)
+    {
+        Result = GetExceptionCode();
+
+        IoStatus->Information = 0;
+        IoStatus->Status = Result;
+    }
+
+    return Result;
+}
+
 NTSTATUS FspQuerySecurityDescriptorInfo(SECURITY_INFORMATION SecurityInformation,
     PSECURITY_DESCRIPTOR SecurityDescriptor, PULONG PLength,
     PSECURITY_DESCRIPTOR ObjectsSecurityDescriptor)

tst/winfsp-tests/memfs.cpp

@@ -501,6 +501,14 @@ static NTSTATUS Write(FSP_FILE_SYSTEM *FileSystem,
     return STATUS_SUCCESS;
 }
 
+NTSTATUS Flush(FSP_FILE_SYSTEM *FileSystem,
+    FSP_FSCTL_TRANSACT_REQ *Request,
+    PVOID FileNode)
+{
+    /* nothing to do, since we do not cache anything */
+    return STATUS_SUCCESS;
+}
+
 static NTSTATUS GetFileInfo(FSP_FILE_SYSTEM *FileSystem,
     FSP_FSCTL_TRANSACT_REQ *Request,
     PVOID FileNode0,
@@ -802,6 +810,7 @@ static FSP_FILE_SYSTEM_INTERFACE MemfsInterface =
     Close,
     Read,
     Write,
+    Flush,
     GetFileInfo,
     SetBasicInfo,
     SetAllocationSize,