/*

 * Copyright (c) 2020 Red Hat, Inc.

 *

 * This program is free software; you can redistribute it and/or

 * modify it under the terms of the GNU General Public License

 * as published by the Free Software Foundation; either version 2

 * of the License, or (at your option) any later version.

 * 

 * This program 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 General Public License for more details.

 * 

 * You should have received a copy of the GNU General Public License

 * along with this program; if not, write to the Free Software

 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA

 * 02110-1301, USA. 

 *

 * $Id: //eng/vdo-releases/aluminum/src/c++/vdo/base/flush.h#1 $

 */

#ifndef FLUSH_H

#define FLUSH_H

#include "types.h"

#include "waitQueue.h"

/**

 * A marker for tracking which journal entries are affected by a flush request.

 **/

struct vdoFlush {

  /** The wait queue entry for this flush */

  Waiter         waiter;

  /** Which flush this struct represents */

  SequenceNumber flushGeneration;

};

/**

 * Make a flusher for a VDO.

 *

 * @param vdo  The VDO which owns the flusher

 *

 * @return VDO_SUCCESS or an error

 **/

int makeFlusher(VDO *vdo)

  __attribute__((warn_unused_result));

/**

 * Free a flusher and null out the reference to it.

 *

 * @param flusherPtr  A pointer to the flusher to free

 **/

void freeFlusher(Flusher **flusherPtr);

/**

 * Get the ID of the thread on which flusher functions should be called.

 *

 * @param flusher  The flusher to query

 *

 * @return The ID of the thread which handles the flusher

 **/

ThreadID getFlusherThreadID(Flusher *flusher)

  __attribute__((warn_unused_result));

/**

 * Handle empty flush requests.

 *

 * @param vdo       The VDO

 * @param vdoFlush  The opaque flush request

 **/

void flush(VDO *vdo, VDOFlush *vdoFlush);

/**

 * Attempt to complete any flushes which might have finished.

 *

 * @param flusher  The flusher

 **/

void completeFlushes(Flusher *flusher);

/**

 * Dump the flusher, in a thread-unsafe fashion.

 *

 * @param flusher  The flusher

 **/

void dumpFlusher(const Flusher *flusher);

#endif /* FLUSH_H */