Function Ext2bhReaperThread

Ext4Fsd/memory.c:3211–3296

Reaper thread to release unused buffer heads */

/* Reaper thread to release unused buffer heads */
VOID
Ext2bhReaperThread(
    PVOID   Context
)
{
    PEXT2_REAPER    Reaper = Context;
    PEXT2_VCB       Vcb = NULL;
    LIST_ENTRY      List, *Link;
    LARGE_INTEGER   Timeout;

    BOOLEAN         GlobalAcquired = FALSE;
    BOOLEAN         DidNothing = FALSE;
    BOOLEAN         NonWait = FALSE;

    __try {

        Reaper->Thread = PsGetCurrentThread();

        /* wake up DirverEntry */
        KeSetEvent(&Reaper->Engine, 0, FALSE);

        /* now process looping */
        while (!IsFlagOn(Reaper->Flags, EXT2_REAPER_FLAG_STOP)) {

            /* wait until it is waken or it times out */
            if (NonWait) {
                Timeout.QuadPart = (LONGLONG)-10*1000*10;
                NonWait = FALSE;
            } else if (DidNothing) {
                Timeout.QuadPart = Timeout.QuadPart * 2;
            } else {
                Timeout.QuadPart = (LONGLONG)-10*1000*1000*10; /* 10 seconds */
            }
            KeWaitForSingleObject(
                &Reaper->Wait,
                Executive,
                KernelMode,
                FALSE,
                &Timeout
            );

            if (IsFlagOn(Reaper->Flags, EXT2_REAPER_FLAG_STOP))
                break;

            InitializeListHead(&List);

            /* acquire global exclusive lock */
            ExAcquireResourceSharedLite(&Ext2Global->Resource, TRUE);
            GlobalAcquired = TRUE;
            /* search all Vcb to get unused resources freed to system */
            for (Link = Ext2Global->VcbList.Flink;
                 Link != &(Ext2Global->VcbList);
                 Link = Link->Flink ) {

                Vcb = CONTAINING_RECORD(Link, EXT2_VCB, Next);
                NonWait = Ext2QueryUnusedBH(Vcb, &List);
            }
            DidNothing = IsListEmpty(&List);