From 37f99929f7cfe986058da46da907ca8158550230 Mon Sep 17 00:00:00 2001
From: Bill Zissimopoulos <billziss@navimatics.com>
Date: Wed, 9 Mar 2016 20:31:19 -0800
Subject: [PATCH] sys: callbacks.c

---
 src/sys/callbacks.c | 33 +++++++++++++++++++++++++++++----
 src/sys/file.c      |  2 +-
 2 files changed, 30 insertions(+), 5 deletions(-)

diff --git a/src/sys/callbacks.c b/src/sys/callbacks.c
index 6b867342..40853078 100644
--- a/src/sys/callbacks.c
+++ b/src/sys/callbacks.c
@@ -92,8 +92,10 @@ NTSTATUS FspAcquireForModWrite(
 
     FSP_FILE_NODE *FileNode = FileObject->FsContext;
 
+    ASSERT((PIRP)FSRTL_MOD_WRITE_TOP_LEVEL_IRP == IoGetTopLevelIrp());
     FspFileNodeAcquireExclusive(FileNode, Full);
-    *ResourceToRelease = 0;
+    *ResourceToRelease = FileNode->Header.PagingIoResource;
+        /* ignored by us, but ModWriter expects it; any (non-NULL) resource will do */
 
     FSP_LEAVE("FileObject=%p", FileObject);
 }
@@ -108,6 +110,7 @@ NTSTATUS FspReleaseForModWrite(
     FSP_FILE_NODE *FileNode = FileObject->FsContext;
 
     FspFileNodeRelease(FileNode, Full);
+    ASSERT((PIRP)FSRTL_MOD_WRITE_TOP_LEVEL_IRP == IoGetTopLevelIrp());
 
     FSP_LEAVE("FileObject=%p", FileObject);
 }
@@ -119,8 +122,13 @@ NTSTATUS FspAcquireForCcFlush(
     FSP_ENTER(PAGED_CODE());
 
     FSP_FILE_NODE *FileNode = FileObject->FsContext;
+    PIRP TopLevelIrp = IoGetTopLevelIrp();
 
+    ASSERT(0 == TopLevelIrp ||
+        (PIRP)FSRTL_MAX_TOP_LEVEL_IRP_FLAG < TopLevelIrp);
     FspFileNodeAcquireExclusive(FileNode, Full);
+    if (0 == TopLevelIrp)
+        IoSetTopLevelIrp((PIRP)FSRTL_CACHE_TOP_LEVEL_IRP);
 
     FSP_LEAVE("FileObject=%p", FileObject);
 }
@@ -132,7 +140,12 @@ NTSTATUS FspReleaseForCcFlush(
     FSP_ENTER(PAGED_CODE());
 
     FSP_FILE_NODE *FileNode = FileObject->FsContext;
+    PIRP TopLevelIrp = IoGetTopLevelIrp();
 
+    ASSERT((PIRP)FSRTL_CACHE_TOP_LEVEL_IRP == TopLevelIrp ||
+        (PIRP)FSRTL_MAX_TOP_LEVEL_IRP_FLAG < TopLevelIrp);
+    if ((PIRP)FSRTL_CACHE_TOP_LEVEL_IRP == TopLevelIrp)
+        IoSetTopLevelIrp(0);
     FspFileNodeRelease(FileNode, Full);
 
     FSP_LEAVE("FileObject=%p", FileObject);
@@ -146,7 +159,10 @@ BOOLEAN FspAcquireForLazyWrite(
 
     FSP_FILE_NODE *FileNode = Context;
 
-    FspFileNodeAcquireExclusive(FileNode, Full);
+    ASSERT(0 == IoGetTopLevelIrp());
+    Result = FspFileNodeTryAcquireExclusiveF(FileNode, FspFileNodeAcquireFull, Wait);
+    if (Result)
+        IoSetTopLevelIrp((PIRP)FSRTL_CACHE_TOP_LEVEL_IRP);
 
     FSP_LEAVE_BOOL("Context=%p, Wait=%d", Context, Wait);
 }
@@ -158,6 +174,8 @@ VOID FspReleaseFromLazyWrite(
 
     FSP_FILE_NODE *FileNode = Context;
 
+    ASSERT((PIRP)FSRTL_CACHE_TOP_LEVEL_IRP == IoGetTopLevelIrp());
+    IoSetTopLevelIrp(0);
     FspFileNodeRelease(FileNode, Full);
 
     FSP_LEAVE_VOID("Context=%p", Context);
@@ -171,7 +189,10 @@ BOOLEAN FspAcquireForReadAhead(
 
     FSP_FILE_NODE *FileNode = Context;
 
-    FspFileNodeAcquireShared(FileNode, Full);
+    ASSERT(0 == IoGetTopLevelIrp());
+    Result = FspFileNodeTryAcquireSharedF(FileNode, FspFileNodeAcquireFull, Wait);
+    if (Result)
+        IoSetTopLevelIrp((PIRP)FSRTL_CACHE_TOP_LEVEL_IRP);
 
     FSP_LEAVE_BOOL("Context=%p, Wait=%d", Context, Wait);
 }
@@ -183,6 +204,8 @@ VOID FspReleaseFromReadAhead(
 
     FSP_FILE_NODE *FileNode = Context;
 
+    ASSERT((PIRP)FSRTL_CACHE_TOP_LEVEL_IRP == IoGetTopLevelIrp());
+    IoSetTopLevelIrp(0);
     FspFileNodeRelease(FileNode, Full);
 
     FSP_LEAVE_VOID("Context=%p", Context);
@@ -197,7 +220,9 @@ VOID FspPropagateTopFlags(PIRP Irp, PIRP TopLevelIrp)
 
     PAGED_CODE();
 
-    if (FSRTL_MAX_TOP_LEVEL_IRP_FLAG >= (UINT_PTR)TopLevelIrp)
+    ASSERT(0 != Irp && 0 != TopLevelIrp);
+
+    if ((PIRP)FSRTL_MAX_TOP_LEVEL_IRP_FLAG >= TopLevelIrp)
     {
         DEBUGBREAK_EX(iorecu);
 
diff --git a/src/sys/file.c b/src/sys/file.c
index 6ebff8eb..c1efe0ec 100644
--- a/src/sys/file.c
+++ b/src/sys/file.c
@@ -63,7 +63,7 @@ VOID FspFileDescDelete(FSP_FILE_DESC *FileDesc);
 
 #define FSP_FILE_NODE_GET_FLAGS()       \
     PIRP Irp = IoGetTopLevelIrp();      \
-    BOOLEAN IrpValid = FSRTL_MAX_TOP_LEVEL_IRP_FLAG < (UINT_PTR)Irp &&\
+    BOOLEAN IrpValid = (PIRP)FSRTL_MAX_TOP_LEVEL_IRP_FLAG < Irp &&\
         IO_TYPE_IRP == Irp->Type;\
     if (IrpValid)                       \
         Flags &= ~FspIrpTopFlags(Irp);