MmDoesFileHaveUserWritableReferences function (ntifs.h)
The MmDoesFileHaveUserWritableReferences function determines whether a file associated with a transaction has any user-mapped sections present.
Syntax
ULONG MmDoesFileHaveUserWritableReferences(
[in] PSECTION_OBJECT_POINTERS SectionPointer
);
Parameters
[in] SectionPointer
Pointer to a SECTION_OBJECT_POINTERS structure that contains the file object's section object pointers. This parameter is required and can't be NULL.
Return value
MmDoesFileHaveUserWritableReferences returns one of the following values.
| Return value | Meaning |
|---|---|
| 0 | The file object has no user-mapped sections. It's safe to proceed with the transaction. |
| 1 | The file object has user-mapped sections. The transaction must be rolled back. |
Remarks
For transactional file systems, you can use this function to determine if a given transaction is referencing a file object that can change. If so, the transaction must be rolled back because atomicity can't be guaranteed.
Prior to calling MmDoesFileHaveUserWritableReferences, transactional file systems must check and intercept the creation of file objects that specify write access. Specifically, prior to starting a transaction, transactional file systems must ensure that there are no writable file objects that currently exist for the given file in the transaction. While the transaction is ongoing, transactional file systems must fail the requests to create file objects with write access for the transacted files.
This function can be used to detect if there are writable views for a file object even when all file handles and section handles for the file object have been closed.
For more information about transactions, see Kernel Transaction Manager.
For more information about file objects, see FILE_OBJECT.
Requirements
| Requirement | Value |
|---|---|
| Minimum supported client | Windows Vista |
| Target Platform | Universal |
| Header | ntifs.h (include Fltkernel.h, Ntifs.h) |
| Library | NtosKrnl.lib |
| DLL | NtosKrnl.exe |
| IRQL | <= APC_LEVEL |
| DDI compliance rules | HwStorPortProhibitedDDIs(storport) |