sys,dll,inc: implement user mode locking

inc/winfsp/fsctl.h

@@ -153,7 +153,8 @@ typedef struct
     UINT32 PassQueryDirectoryPattern:1;     /* pass Pattern during QueryDirectory operations */
     UINT32 AlwaysUseDoubleBuffering:1;
     UINT32 PassQueryDirectoryFileName:1;    /* pass FileName during QueryDirectory (GetDirInfoByName) */
-    UINT32 KmReservedFlags:2;
+    UINT32 UserModeFileLocking:1;           /* pass file locking requests to user mode */
+    UINT32 KmReservedFlags:1;
     /* user-mode flags */
     UINT32 UmFileContextIsUserContext2:1;   /* user mode: FileContext parameter is UserContext2 */
     UINT32 UmFileContextIsFullContext:1;    /* user mode: FileContext parameter is FullContext */
@@ -259,6 +260,7 @@ typedef struct
             UINT32 SetLastAccessTime:1;
             UINT32 SetLastWriteTime:1;
             UINT32 SetChangeTime:1;
+            UINT32 UnlockAll:1;
         } Cleanup;
         struct
         {
@@ -273,6 +275,7 @@ typedef struct
             UINT64 Offset;
             UINT32 Length;
             UINT32 Key;
+            UINT32 ProcessId;
         } Read;
         struct
         {
@@ -283,6 +286,8 @@ typedef struct
             UINT32 Length;
             UINT32 Key;
             UINT32 ConstrainedIo:1;
+            UINT32 ReservedFlags:31;
+            UINT32 ProcessId;
         } Write;
         struct
         {
@@ -359,6 +364,18 @@ typedef struct
             UINT16 TargetOnFileSystem;  /* the target of the symbolic link is on this file system */
         } FileSystemControl;
         struct
+        {
+            UINT64 UserContext;
+            UINT64 UserContext2;
+            UINT32 LockFunction;
+            UINT64 Offset;
+            UINT64 Length;
+            UINT32 Key;
+            UINT32 ProcessId;
+            UINT32 Exclusive:1;
+            UINT32 FailImmediately:1;
+        } LockControl;
+        struct
         {
             UINT64 UserContext;
             UINT64 UserContext2;

inc/winfsp/winfsp.h

@@ -133,6 +133,7 @@ enum
     FspCleanupSetLastAccessTime         = 0x20,
     FspCleanupSetLastWriteTime          = 0x40,
     FspCleanupSetChangeTime             = 0x80,
+    FspCleanupUnlockAll                 = 0x0100,
 };
 /**
  * @class FSP_FILE_SYSTEM
@@ -822,12 +823,80 @@ typedef struct _FSP_FILE_SYSTEM_INTERFACE
     NTSTATUS (*GetDirInfoByName)(FSP_FILE_SYSTEM *FileSystem,
         PVOID FileContext, PWSTR FileName,
         FSP_FSCTL_DIR_INFO *DirInfo);
+    /**
+     * Lock a file range.
+     *
+     * At the time of this call the FSD has already done its own locking processing.
+     * Thus the kernel may fail a lock control request or a Read or Write without
+     * informing the user mode file system.
+     *
+     * @param FileSystem
+     *     The file system on which this request is posted.
+     * @param FileContext
+     *     The file context of the file to be locked.
+     * @param Offset
+     *     Offset within the file to lock.
+     * @param Length
+     *     Length of data to lock.
+     * @param Owner
+     *     Lock owner. This 64-bit value consists of a PID in the high 32-bits and a "Key"
+     *     in the low 32-bits. The PID is that of the process requesting the lock. The Key
+     *     is an arbitrary value.
+     *
+     *     The triplet (FileDesc,PID,Key) uniquely identifies the lock owner.
+     * @param Exclusive
+     *     When TRUE an exclusive lock is requested. Otherwise a shared lock is requested.
+     * @param FailImmediately
+     *     When TRUE the function should return immediately if it is unable to acquire the
+     *     requested lock. Otherwise the function should wait until the lock can be granted.
+     *     In this case the function may also return STATUS_PENDING.
+     * @return
+     *     STATUS_SUCCESS or error code. STATUS_PENDING is supported allowing for asynchronous
+     *     operation.
+     */
+    NTSTATUS (*Lock)(FSP_FILE_SYSTEM *FileSystem,
+        PVOID FileContext, UINT64 Offset, UINT64 Length, UINT64 Owner,
+        BOOLEAN Exclusive, BOOLEAN FailImmediately);
+    /**
+     * Unlock file ranges.
+     *
+     * At the time of this call the FSD has already done its own locking processing.
+     * Thus the kernel may fail a lock control request or a Read or Write without
+     * informing the user mode file system.
+     *
+     * An Unlock operation with Offset == Length == -1 is a request to remove multiple locks.
+     * The set of possible locks to remove includes all locks made by the process described
+     * by the Owner parameter through the file descriptor described by the FileContext parameter.
+     * If the Key portion of the Owner parameter is 0, all the locks in the set are removed.
+     * If the Key portion of the Owner paramter is non-0, only locks that match the Key are
+     * removed.
+     *
+     * @param FileSystem
+     *     The file system on which this request is posted.
+     * @param FileContext
+     *     The file context of the file to be unlocked.
+     * @param Offset
+     *     Offset within the file to unlock.
+     * @param Length
+     *     Length of data to unlock.
+     * @param Owner
+     *     Lock owner. This 64-bit value consists of a PID in the high 32-bits and a "Key"
+     *     in the low 32-bits. The PID is that of the process requesting the lock. The Key
+     *     is an arbitrary value.
+     *
+     *     The triplet (FileDesc,PID,Key) uniquely identifies the lock owner.
+     * @return
+     *     STATUS_SUCCESS or error code. STATUS_PENDING is supported allowing for asynchronous
+     *     operation.
+     */
+    NTSTATUS (*Unlock)(FSP_FILE_SYSTEM *FileSystem,
+        PVOID FileContext, UINT64 Offset, UINT64 Length, UINT64 Owner);
 
     /*
      * This ensures that this interface will always contain 64 function pointers.
      * Please update when changing the interface as it is important for future compatibility.
      */
-    NTSTATUS (*Reserved[39])();
+    NTSTATUS (*Reserved[37])();
 } FSP_FILE_SYSTEM_INTERFACE;
 FSP_FSCTL_STATIC_ASSERT(sizeof(FSP_FILE_SYSTEM_INTERFACE) == 64 * sizeof(NTSTATUS (*)()),
     "FSP_FILE_SYSTEM_INTERFACE must have 64 entries.");
@@ -1086,7 +1155,7 @@ BOOLEAN FspFileSystemIsOperationCaseSensitive(VOID)
 }
 FSP_API BOOLEAN FspFileSystemIsOperationCaseSensitiveF(VOID);
 /**
- * Gets the originating process ID.
+ * Get the originating process ID.
  *
  * Valid only during Create, Open and Rename requests when the target exists.
  */
@@ -1107,6 +1176,28 @@ UINT32 FspFileSystemOperationProcessId(VOID)
     }
 }
 FSP_API UINT32 FspFileSystemOperationProcessIdF(VOID);
+/**
+ * Get the lock owner.
+ *
+ * Valid only during Read, Write, Lock and Unlock requests.
+ */
+static inline
+UINT64 FspFileSystemOperationLockOwner(VOID)
+{
+    FSP_FSCTL_TRANSACT_REQ *Request = FspFileSystemGetOperationContext()->Request;
+    switch (Request->Kind)
+    {
+    case FspFsctlTransactReadKind:
+        return ((UINT64)Request->Req.Read.ProcessId << 32) | (UINT64)Request->Req.Read.Key;
+    case FspFsctlTransactWriteKind:
+        return ((UINT64)Request->Req.Write.ProcessId << 32) | (UINT64)Request->Req.Write.Key;
+    case FspFsctlTransactLockControlKind:
+        return ((UINT64)Request->Req.LockControl.ProcessId << 32) | (UINT64)Request->Req.LockControl.Key;
+    default:
+        return 0;
+    }
+}
+FSP_API UINT64 FspFileSystemOperationLockOwnerF(VOID);
 
 /*
  * Operations
@@ -1141,6 +1232,8 @@ FSP_API NTSTATUS FspFileSystemOpQueryDirectory(FSP_FILE_SYSTEM *FileSystem,
     FSP_FSCTL_TRANSACT_REQ *Request, FSP_FSCTL_TRANSACT_RSP *Response);
 FSP_API NTSTATUS FspFileSystemOpFileSystemControl(FSP_FILE_SYSTEM *FileSystem,
     FSP_FSCTL_TRANSACT_REQ *Request, FSP_FSCTL_TRANSACT_RSP *Response);
+FSP_API NTSTATUS FspFileSystemOpLockControl(FSP_FILE_SYSTEM *FileSystem,
+    FSP_FSCTL_TRANSACT_REQ *Request, FSP_FSCTL_TRANSACT_RSP *Response);
 FSP_API NTSTATUS FspFileSystemOpQuerySecurity(FSP_FILE_SYSTEM *FileSystem,
     FSP_FSCTL_TRANSACT_REQ *Request, FSP_FSCTL_TRANSACT_RSP *Response);
 FSP_API NTSTATUS FspFileSystemOpSetSecurity(FSP_FILE_SYSTEM *FileSystem,

src/dll/fs.c

@@ -162,6 +162,7 @@ FSP_API NTSTATUS FspFileSystemCreate(PWSTR DevicePath,
     FileSystem->Operations[FspFsctlTransactSetVolumeInformationKind] = FspFileSystemOpSetVolumeInformation;
     FileSystem->Operations[FspFsctlTransactQueryDirectoryKind] = FspFileSystemOpQueryDirectory;
     FileSystem->Operations[FspFsctlTransactFileSystemControlKind] = FspFileSystemOpFileSystemControl;
+    FileSystem->Operations[FspFsctlTransactLockControlKind] = FspFileSystemOpLockControl;
     FileSystem->Operations[FspFsctlTransactQuerySecurityKind] = FspFileSystemOpQuerySecurity;
     FileSystem->Operations[FspFsctlTransactSetSecurityKind] = FspFileSystemOpSetSecurity;
     FileSystem->Operations[FspFsctlTransactQueryStreamInformationKind] = FspFileSystemOpQueryStreamInformation;
@@ -688,3 +689,8 @@ FSP_API UINT32 FspFileSystemOperationProcessIdF(VOID)
 {
     return FspFileSystemOperationProcessId();
 }
+
+FSP_API UINT64 FspFileSystemOperationLockOwnerF(VOID)
+{
+    return FspFileSystemOperationLockOwner();
+}

src/dll/fsop.c

@@ -886,6 +886,7 @@ FSP_API NTSTATUS FspFileSystemOpCleanup(FSP_FILE_SYSTEM *FileSystem,
             (0 != Request->Req.Cleanup.SetArchiveBit ? FspCleanupSetArchiveBit : 0) |
             (0 != Request->Req.Cleanup.SetLastAccessTime ? FspCleanupSetLastAccessTime : 0) |
             (0 != Request->Req.Cleanup.SetLastWriteTime ? FspCleanupSetLastWriteTime : 0) |
+            (0 != Request->Req.Cleanup.UnlockAll ? FspCleanupUnlockAll : 0) |
             (0 != Request->Req.Cleanup.SetChangeTime ? FspCleanupSetChangeTime : 0));
 
     return STATUS_SUCCESS;
@@ -1247,6 +1248,43 @@ FSP_API NTSTATUS FspFileSystemOpFileSystemControl(FSP_FILE_SYSTEM *FileSystem,
     return Result;
 }
 
+FSP_API NTSTATUS FspFileSystemOpLockControl(FSP_FILE_SYSTEM *FileSystem,
+    FSP_FSCTL_TRANSACT_REQ *Request, FSP_FSCTL_TRANSACT_RSP *Response)
+{
+    NTSTATUS Result;
+
+    Result = STATUS_INVALID_DEVICE_REQUEST;
+    switch (Request->Req.LockControl.LockFunction)
+    {
+    case 0x01/*IRP_MN_LOCK*/:
+        if (0 != FileSystem->Interface->Lock)
+            Result = FileSystem->Interface->Lock(FileSystem,
+                (PVOID)ValOfFileContext(Request->Req.LockControl),
+                Request->Req.LockControl.Offset, Request->Req.LockControl.Length,
+                ((UINT64)Request->Req.LockControl.ProcessId << 32) | (UINT64)Request->Req.LockControl.Key,
+                0 != Request->Req.LockControl.Exclusive,
+                0 != Request->Req.LockControl.FailImmediately);
+        break;
+    case 0x02/*IRP_MN_UNLOCK_SINGLE*/:
+        if (0 != FileSystem->Interface->Unlock)
+            Result = FileSystem->Interface->Unlock(FileSystem,
+                (PVOID)ValOfFileContext(Request->Req.LockControl),
+                Request->Req.LockControl.Offset, Request->Req.LockControl.Length,
+                ((UINT64)Request->Req.LockControl.ProcessId << 32) | (UINT64)Request->Req.LockControl.Key);
+        break;
+    case 0x03/*IRP_MN_UNLOCK_ALL*/:
+    case 0x04/*IRP_MN_UNLOCK_ALL_BY_KEY*/:
+        if (0 != FileSystem->Interface->Unlock)
+            Result = FileSystem->Interface->Unlock(FileSystem,
+                (PVOID)ValOfFileContext(Request->Req.LockControl),
+                (UINT64)-1LL, (UINT64)-1LL,
+                ((UINT64)Request->Req.LockControl.ProcessId << 32) | (UINT64)Request->Req.LockControl.Key);
+        break;
+    }
+
+    return Result;
+}
+
 FSP_API NTSTATUS FspFileSystemOpQuerySecurity(FSP_FILE_SYSTEM *FileSystem,
     FSP_FSCTL_TRANSACT_REQ *Request, FSP_FSCTL_TRANSACT_RSP *Response)
 {

src/sys/cleanup.c

@@ -117,6 +117,8 @@ static NTSTATUS FspFsvolCleanup(
     Request->Req.Cleanup.SetLastWriteTime = FileModified && !FileDesc->DidSetLastWriteTime;
     Request->Req.Cleanup.SetChangeTime = (FileModified || FileDesc->DidSetMetadata) &&
         !FileDesc->DidSetChangeTime;
+    Request->Req.Cleanup.UnlockAll = FsvolDeviceExtension->VolumeParams.UserModeFileLocking &&
+        FsRtlAreThereCurrentOrInProgressFileLocks(&FileNode->FileLock);
 
     FspFileNodeAcquireExclusive(FileNode, Pgio);
 
@@ -128,6 +130,7 @@ static NTSTATUS FspFsvolCleanup(
         Request->Req.Cleanup.SetArchiveBit ||
         Request->Req.Cleanup.SetLastWriteTime ||
         Request->Req.Cleanup.SetChangeTime ||
+        Request->Req.Cleanup.UnlockAll ||
         !FsvolDeviceExtension->VolumeParams.PostCleanupWhenModifiedOnly)
         /*
          * Note that it is still possible for this request to not be delivered,

src/sys/driver.c

@@ -128,6 +128,7 @@ NTSTATUS DriverEntry(
     FspIopCompleteFunction[IRP_MJ_FILE_SYSTEM_CONTROL] = FspFsvolFileSystemControlComplete;
     FspIopCompleteFunction[IRP_MJ_DEVICE_CONTROL] = FspFsvolDeviceControlComplete;
     FspIopCompleteFunction[IRP_MJ_SHUTDOWN] = FspFsvolShutdownComplete;
+    FspFileNodeCompleteLockIrp = FspFsvolLockControlForward;
     FspIopCompleteFunction[IRP_MJ_LOCK_CONTROL] = FspFsvolLockControlComplete;
     FspIopCompleteFunction[IRP_MJ_CLEANUP] = FspFsvolCleanupComplete;
     FspIopCompleteFunction[IRP_MJ_QUERY_SECURITY] = FspFsvolQuerySecurityComplete;

src/sys/driver.h

@@ -316,6 +316,7 @@ FSP_IOPREP_DISPATCH FspFsvolDirectoryControlPrepare;
 FSP_IOCMPL_DISPATCH FspFsvolDirectoryControlComplete;
 FSP_IOCMPL_DISPATCH FspFsvolFileSystemControlComplete;
 FSP_IOCMPL_DISPATCH FspFsvolFlushBuffersComplete;
+NTSTATUS FspFsvolLockControlForward(PVOID Context, PIRP Irp);
 FSP_IOCMPL_DISPATCH FspFsvolLockControlComplete;
 FSP_IOCMPL_DISPATCH FspFsvolQueryEaComplete;
 FSP_IOCMPL_DISPATCH FspFsvolQueryInformationComplete;
@@ -1564,6 +1565,7 @@ extern CACHE_MANAGER_CALLBACKS FspCacheManagerCallbacks;
 extern FSP_IOPREP_DISPATCH *FspIopPrepareFunction[];
 extern FSP_IOCMPL_DISPATCH *FspIopCompleteFunction[];
 extern ERESOURCE FspDeviceGlobalResource;
+extern PCOMPLETE_LOCK_IRP_ROUTINE FspFileNodeCompleteLockIrp;
 extern WCHAR FspFileDescDirectoryPatternMatchAll[];
 extern const GUID FspMainFileOpenEcpGuid;
 extern ULONG FspProcessorCount;

src/sys/file.c

@@ -83,7 +83,6 @@ VOID FspFileNodeInvalidateStreamInfo(FSP_FILE_NODE *FileNode);
 VOID FspFileNodeNotifyChange(FSP_FILE_NODE *FileNode, ULONG Filter, ULONG Action,
     BOOLEAN InvalidateCaches);
 NTSTATUS FspFileNodeProcessLockIrp(FSP_FILE_NODE *FileNode, PIRP Irp);
-static NTSTATUS FspFileNodeCompleteLockIrp(PVOID Context, PIRP Irp);
 NTSTATUS FspFileDescCreate(FSP_FILE_DESC **PFileDesc);
 VOID FspFileDescDelete(FSP_FILE_DESC *FileDesc);
 NTSTATUS FspFileDescResetDirectory(FSP_FILE_DESC *FileDesc,
@@ -149,7 +148,6 @@ VOID FspFileNodeOplockComplete(PVOID Context, PIRP Irp);
 // !#pragma alloc_text(PAGE, FspFileNodeInvalidateStreamInfo)
 #pragma alloc_text(PAGE, FspFileNodeNotifyChange)
 #pragma alloc_text(PAGE, FspFileNodeProcessLockIrp)
-#pragma alloc_text(PAGE, FspFileNodeCompleteLockIrp)
 #pragma alloc_text(PAGE, FspFileDescCreate)
 #pragma alloc_text(PAGE, FspFileDescDelete)
 #pragma alloc_text(PAGE, FspFileDescResetDirectory)
@@ -2030,19 +2028,6 @@ NTSTATUS FspFileNodeProcessLockIrp(FSP_FILE_NODE *FileNode, PIRP Irp)
     return Result;
 }
 
-static NTSTATUS FspFileNodeCompleteLockIrp(PVOID Context, PIRP Irp)
-{
-    PAGED_CODE();
-
-    NTSTATUS Result = Irp->IoStatus.Status;
-
-    DEBUGLOGIRP(Irp, Result);
-
-    FspIopCompleteIrp(Irp, Result);
-
-    return Result;
-}
-
 NTSTATUS FspFileDescCreate(FSP_FILE_DESC **PFileDesc)
 {
     PAGED_CODE();
@@ -2379,6 +2364,7 @@ VOID FspFileNodeOplockComplete(PVOID Context, PIRP Irp)
         FspIopCompleteIrp(Irp, Irp->IoStatus.Status);
 }
 
+PCOMPLETE_LOCK_IRP_ROUTINE FspFileNodeCompleteLockIrp;
 WCHAR FspFileDescDirectoryPatternMatchAll[] = L"*";
 
 // {904862B4-EB3F-461E-ACB2-4DF2B3FC898B}

src/sys/lockctl.c

@@ -22,12 +22,14 @@ static NTSTATUS FspFsvolLockControlRetry(
     BOOLEAN CanWait);
 static NTSTATUS FspFsvolLockControl(
     PDEVICE_OBJECT DeviceObject, PIRP Irp, PIO_STACK_LOCATION IrpSp);
+NTSTATUS FspFsvolLockControlForward(PVOID Context, PIRP Irp);
 FSP_IOCMPL_DISPATCH FspFsvolLockControlComplete;
 FSP_DRIVER_DISPATCH FspLockControl;
 
 #ifdef ALLOC_PRAGMA
 #pragma alloc_text(PAGE, FspFsvolLockControlRetry)
 #pragma alloc_text(PAGE, FspFsvolLockControl)
+#pragma alloc_text(PAGE, FspFsvolLockControlForward)
 #pragma alloc_text(PAGE, FspFsvolLockControlComplete)
 #pragma alloc_text(PAGE, FspLockControl)
 #endif
@@ -94,6 +96,57 @@ static NTSTATUS FspFsvolLockControl(
     return Result;
 }
 
+NTSTATUS FspFsvolLockControlForward(PVOID Context, PIRP Irp)
+{
+    /*
+     * At this point the FSRTL package has processed the lock IRP.
+     * Either complete the IRP or if we are supposed to forward to
+     * user mode do so now.
+     */
+
+    PAGED_CODE();
+
+    PIO_STACK_LOCATION IrpSp = IoGetCurrentIrpStackLocation(Irp);
+    PDEVICE_OBJECT FsvolDeviceObject = IrpSp->DeviceObject;
+    FSP_FSVOL_DEVICE_EXTENSION *FsvolDeviceExtension = FspFsvolDeviceExtension(FsvolDeviceObject);
+    NTSTATUS Result = Irp->IoStatus.Status;
+
+    if (!NT_SUCCESS(Result) || !FsvolDeviceExtension->VolumeParams.UserModeFileLocking)
+        goto complete;
+
+    PFILE_OBJECT FileObject = IrpSp->FileObject;
+    FSP_FILE_NODE *FileNode = FileObject->FsContext;
+    FSP_FILE_DESC *FileDesc = FileObject->FsContext2;
+    FSP_FSCTL_TRANSACT_REQ *Request;
+
+    ASSERT(FileNode == FileDesc->FileNode);
+
+    Result = FspIopCreateRequest(Irp, 0, 0, &Request);
+    if (!NT_SUCCESS(Result))
+        goto complete;
+
+    Request->Kind = FspFsctlTransactLockControlKind;
+    Request->Req.LockControl.UserContext = FileNode->UserContext;
+    Request->Req.LockControl.UserContext2 = FileDesc->UserContext2;
+    Request->Req.LockControl.LockFunction = IrpSp->MinorFunction;
+    Request->Req.LockControl.Offset = IrpSp->Parameters.LockControl.ByteOffset.QuadPart;
+    Request->Req.LockControl.Length = IrpSp->Parameters.LockControl.Length->QuadPart;
+    Request->Req.LockControl.Key = IrpSp->Parameters.LockControl.Key;
+    Request->Req.LockControl.ProcessId = IoGetRequestorProcessId(Irp);
+    Request->Req.LockControl.Exclusive = 0 != (IrpSp->Flags & SL_EXCLUSIVE_LOCK);
+    Request->Req.LockControl.FailImmediately = 0 != (IrpSp->Flags & SL_FAIL_IMMEDIATELY);
+
+    if (!FspIoqPostIrp(FsvolDeviceExtension->Ioq, Irp, &Result))
+        goto complete;
+
+    return Result;
+
+complete:
+    DEBUGLOGIRP(Irp, Result);
+    FspIopCompleteIrp(Irp, Result);
+    return Result;
+}
+
 NTSTATUS FspFsvolLockControlComplete(
     PIRP Irp, const FSP_FSCTL_TRANSACT_RSP *Response)
 {

src/sys/read.c

@@ -228,7 +228,6 @@ static NTSTATUS FspFsvolReadNonCached(
     FSP_FILE_DESC *FileDesc = FileObject->FsContext2;
     LARGE_INTEGER ReadOffset = IrpSp->Parameters.Read.ByteOffset;
     ULONG ReadLength = IrpSp->Parameters.Read.Length;
-    ULONG ReadKey = IrpSp->Parameters.Read.Key;
     BOOLEAN PagingIo = BooleanFlagOn(Irp->Flags, IRP_PAGING_IO);
     FSP_FSCTL_TRANSACT_REQ *Request;
     BOOLEAN Success;
@@ -321,7 +320,11 @@ static NTSTATUS FspFsvolReadNonCached(
     Request->Req.Read.UserContext2 = FileDesc->UserContext2;
     Request->Req.Read.Offset = ReadOffset.QuadPart;
     Request->Req.Read.Length = ReadLength;
-    Request->Req.Read.Key = ReadKey;
+    if (!PagingIo)
+    {
+        Request->Req.Read.Key = IrpSp->Parameters.Read.Key;
+        Request->Req.Read.ProcessId = IoGetRequestorProcessId(Irp);
+    }
 
     FspFileNodeSetOwner(FileNode, Full, Request);
     FspIopRequestContext(Request, RequestIrp) = Irp;

src/sys/write.c

@@ -289,7 +289,6 @@ static NTSTATUS FspFsvolWriteNonCached(
     FSP_FILE_DESC *FileDesc = FileObject->FsContext2;
     LARGE_INTEGER WriteOffset = IrpSp->Parameters.Write.ByteOffset;
     ULONG WriteLength = IrpSp->Parameters.Write.Length;
-    ULONG WriteKey = IrpSp->Parameters.Write.Key;
     BOOLEAN WriteToEndOfFile =
         FILE_WRITE_TO_END_OF_FILE == WriteOffset.LowPart && -1L == WriteOffset.HighPart;
     BOOLEAN PagingIo = BooleanFlagOn(Irp->Flags, IRP_PAGING_IO);
@@ -390,8 +389,13 @@ static NTSTATUS FspFsvolWriteNonCached(
     Request->Req.Write.UserContext2 = FileDesc->UserContext2;
     Request->Req.Write.Offset = WriteOffset.QuadPart;
     Request->Req.Write.Length = WriteLength;
-    Request->Req.Write.Key = WriteKey;
+    if (!PagingIo)
-    Request->Req.Write.ConstrainedIo = !!PagingIo;
+    {
+        Request->Req.Write.Key = IrpSp->Parameters.Write.Key;
+        Request->Req.Write.ProcessId = IoGetRequestorProcessId(Irp);
+    }
+    else
+        Request->Req.Write.ConstrainedIo = TRUE;
 
     FspFileNodeSetOwner(FileNode, Full, Request);
     FspIopRequestContext(Request, RequestIrp) = Irp;