Function Ext2QueryUnusedFcb

Ext4Fsd/memory.c:3300–3356

/* get unused Fcbs to free */

BOOLEAN
Ext2QueryUnusedFcb(PEXT2_VCB Vcb, PLIST_ENTRY list)
{
    PEXT2_FCB       Fcb;
    PLIST_ENTRY     next = NULL;
    LARGE_INTEGER   start, now;

    ULONG           count = 0;
    ULONG           tries = 0;
    BOOLEAN         wake = FALSE;
    BOOLEAN         retry = TRUE;

    KeQuerySystemTime(&start);

    ExAcquireResourceExclusiveLite(&Vcb->FcbLock, TRUE);

again:

    KeQuerySystemTime(&now);
    while (!IsListEmpty(&Vcb->FcbList)) {

        next = RemoveHeadList(&Vcb->FcbList);
        Fcb = CONTAINING_RECORD(next, EXT2_FCB, Next);

        if (Fcb->ReferenceCount > 0) {
            InsertTailList(&Vcb->FcbList, &Fcb->Next);
            break;
        }

        retry = FALSE;

        if (now.QuadPart < Fcb->TsDrop.QuadPart + 10*1000*1000*120) {
            InsertHeadList(&Vcb->FcbList, &Fcb->Next);
            break;
        }

        Ext2UnlinkFcb(Fcb);
        Ext2DerefXcb(&Vcb->FcbCount);
        InsertTailList(list, &Fcb->Next);
        if (++count >= Ext2Global->MaxDepth) {
            break;
        }
    }

    if (start.QuadPart + 10*1000*1000 > now.QuadPart) {
        retry = FALSE;
    }

    if (retry) {
        if (++tries < (Vcb->FcbCount >> 4) )
            goto again;
    }

    ExReleaseResourceLite(&Vcb->FcbLock);

    return 0;
}