DispatchFlushBuffers Routines

A driver's DispatchFlushBuffers routine handles IRPs for the IRP_MJ_FLUSH_BUFFERS I/O function code. Driver support for this I/O function code is optional, but all file system and filter drivers that maintain internal data buffers must handle it to preserve changes to file data or metadata across system shutdowns. This request is sent by the I/O manager and other operating system components, as well as other kernel-mode drivers, when buffered data needs to be flushed to disk. For example, it is sent when a user-mode application calls FlushFileBuffers.