/* Copyright (c) Mark Harmstone 2016
 * 
 * This file is part of WinBtrfs.
 * 
 * WinBtrfs is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public Licence as published by
 * the Free Software Foundation, either version 3 of the Licence, or
 * (at your option) any later version.
 * 
 * WinBtrfs is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Lesser General Public Licence for more details.
 * 
 * You should have received a copy of the GNU Lesser General Public Licence
 * along with WinBtrfs.  If not, see <http://www.gnu.org/licenses/>. */

#include "btrfs_drv.h"

#define INTERVAL 15000 // in milliseconds

static void do_flush(device_extension* Vcb) {
    LIST_ENTRY rollback;
    
    InitializeListHead(&rollback);
    
    FsRtlEnterFileSystem();

    acquire_tree_lock(Vcb, TRUE);

    if (Vcb->write_trees > 0)
        do_write(Vcb, &rollback);
    
    free_tree_cache(&Vcb->tree_cache);
    
    clear_rollback(&rollback);

    release_tree_lock(Vcb, TRUE);

    FsRtlExitFileSystem();
}

void STDCALL flush_thread(void* context) {
    device_extension* Vcb = context;
    LARGE_INTEGER due_time;
    
    KeInitializeTimer(&Vcb->flush_thread_timer);
    
    due_time.QuadPart = -INTERVAL * 10000;
    
    KeSetTimer(&Vcb->flush_thread_timer, due_time, NULL);
    
    while (TRUE) {
        KeWaitForSingleObject(&Vcb->flush_thread_timer, Executive, KernelMode, FALSE, NULL);        

        do_flush(Vcb);
        
        KeSetTimer(&Vcb->flush_thread_timer, due_time, NULL);
    }
    
    KeCancelTimer(&Vcb->flush_thread_timer);
    PsTerminateSystemThread(STATUS_SUCCESS);
}