From 0af0bfbe7c45e353d693a2a45965d99fa81f2163 Mon Sep 17 00:00:00 2001
From: Bill Zissimopoulos <billziss@navimatics.com>
Date: Mon, 18 Jan 2021 15:07:57 -0800
Subject: [PATCH] sys: FspFsvolClose: convert CLOSE requests to synchronous
 when above the IOQ watermark

---
 src/sys/close.c  |  5 +++--
 src/sys/driver.h |  1 +
 src/sys/ioq.c    | 10 ++++++++++
 3 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/src/sys/close.c b/src/sys/close.c
index c3b061c1..2b5b189a 100644
--- a/src/sys/close.c
+++ b/src/sys/close.c
@@ -84,8 +84,9 @@ static NTSTATUS FspFsvolClose(
     FspFileDescDelete(FileDesc); /* this will also close the MainFileObject if any */
     FspFileNodeDereference(FileNode);
 
-    /* if we are closing files in the context of a rename make it synchronous */
-    if (FspFsvolDeviceFileRenameIsAcquiredExclusive(FsvolDeviceObject))
+    /* if closing in the context of a rename or IOQ is above the watermark make it synchronous */
+    if (FspFsvolDeviceFileRenameIsAcquiredExclusive(FsvolDeviceObject) ||
+        FspIoqPendingAboveWatermark(FspFsvolDeviceExtension(FsvolDeviceObject)->Ioq, 50))
     {
         /* acquire ownership of the Request */
         Request->Hint = (UINT_PTR)Irp;
diff --git a/src/sys/driver.h b/src/sys/driver.h
index 2f0dc0a3..6a28394c 100644
--- a/src/sys/driver.h
+++ b/src/sys/driver.h
@@ -953,6 +953,7 @@ BOOLEAN FspIoqPostIrpEx(FSP_IOQ *Ioq, PIRP Irp, BOOLEAN BestEffort, NTSTATUS *PR
 PIRP FspIoqNextPendingIrp(FSP_IOQ *Ioq, PIRP BoundaryIrp, PLARGE_INTEGER Timeout,
     PIRP CancellableIrp);
 ULONG FspIoqPendingIrpCount(FSP_IOQ *Ioq);
+BOOLEAN FspIoqPendingAboveWatermark(FSP_IOQ *Ioq, ULONG Watermark);
 BOOLEAN FspIoqStartProcessingIrp(FSP_IOQ *Ioq, PIRP Irp);
 PIRP FspIoqEndProcessingIrp(FSP_IOQ *Ioq, UINT_PTR IrpHint);
 ULONG FspIoqProcessIrpCount(FSP_IOQ *Ioq);
diff --git a/src/sys/ioq.c b/src/sys/ioq.c
index d07cad66..f5d58e24 100644
--- a/src/sys/ioq.c
+++ b/src/sys/ioq.c
@@ -643,6 +643,16 @@ ULONG FspIoqPendingIrpCount(FSP_IOQ *Ioq)
     return Result;
 }
 
+BOOLEAN FspIoqPendingAboveWatermark(FSP_IOQ *Ioq, ULONG Watermark)
+{
+    BOOLEAN Result;
+    KIRQL Irql;
+    KeAcquireSpinLock(&Ioq->SpinLock, &Irql);
+    Result = Watermark < 100 * Ioq->PendingIrpCount / Ioq->PendingIrpCapacity;
+    KeReleaseSpinLock(&Ioq->SpinLock, Irql);
+    return Result;
+}
+
 BOOLEAN FspIoqStartProcessingIrp(FSP_IOQ *Ioq, PIRP Irp)
 {
     NTSTATUS Result;