Hi,
I have a question about how NTFS will 0-fill a file if you SetEndOfFile further down and then write at that new EOF.
- Create a new file on an NTFS volume without specifying no buffering, so will use buffered IO.
- SetFilePointer to 0x1000403.
- SetEndOfFile at that offset.
- WriteFile 4 0’s at that end offset. So size would now be 0x1000407
The 0-fill from start of file up to 0x1000403 occurs as expected during the WriteFile call. But our driver is not seeing ANY such paging IOs. Does NTFS perform the 0-fill without using paging IOs?
BTW I know all about SetFileValidData to get past the 0-fill but not interested in that for this purpose.