Add a check to verify that the TopLevelIrp has not been completed. This
became necessary because on recent Windows kernels, IRP's can have "IRP
extensions", which are freed when an IRP is completed. This can trigger
a recursive CLOSE with a top-level IRP that has been completed, which
can bugcheck the system.
Case in point: the new (Win11) NtCopyFileChunk creates IRP's with
COPY_INFORMATION attached. Upon completion of such an IRP the
SourceFileObject is freed, which results in a recursive IRP_MJ_CLOSE
with a completed top-level IRP, which would lead to a BSOD.
In some rare cases and under load the mapped page writer's TopLevelIrp
may be trashed by some outside component (observed on Windows 10 1909).
For this reason remove an assertion that could trigger in debug builds.
During CreateProcess/CreateSection Windows locks the image file (using AcquireFileForNtCreateSection),
gets the image file size and then reads the image file. Unfortunately if the file system (erroneously) reads
past the file size, Windows can bugcheck. This allows a faulty or malicious file system to crash Windows.
This commit adds a check in WinFsp to mitigate this problem.
