/*

 * 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/blockMapTreeInternals.h#4 $

 */

#ifndef BLOCK_MAP_TREE_INTERNALS_H

#define BLOCK_MAP_TREE_INTERNALS_H

#include "blockMapTree.h"

#include "blockMapPage.h"

#include "types.h"

/** A single page of a block map tree */

struct treePage {

  /** Waiter for a VIO to write out this page */

  Waiter         waiter;

  /** Dirty list node */

  RingNode       node;

  /**

   * If this is a dirty tree page, the tree zone flush generation in which it

   * was last dirtied.

   */

  uint8_t        generation;

  /** Whether this page is an interior tree page being written out. */

  bool           writing;

  /**

   * If this page is being written, the tree zone flush generation of the

   * copy of the page being written.

   **/

  uint8_t        writingGeneration;

  /** The earliest journal block containing uncommitted updates to this page */

  SequenceNumber recoveryLock;

  /** The value of recoveryLock when the this page last started writing */

  SequenceNumber writingRecoveryLock;

  /** The buffer to hold the on-disk representation of this page */

  char           pageBuffer[VDO_BLOCK_SIZE];

};

typedef struct {

  PageNumber levels[BLOCK_MAP_TREE_HEIGHT];

} Boundary;

/**

 * An invalid PBN used to indicate that the page holding the location of a

 * tree root has been "loaded".

 **/

extern const PhysicalBlockNumber INVALID_PBN;

/**

 * Extract the BlockMapPage from a TreePage.

 *

 * @param treePage  The TreePage

 *

 * @return The BlockMapPage of the TreePage

 **/

__attribute__((warn_unused_result))

static inline BlockMapPage *asBlockMapPage(TreePage *treePage)

{

  return (BlockMapPage *) treePage->pageBuffer;

}

/**

 * Replace the VIOPool in a tree zone. This method is used by unit tests.

 *

 * @param zone      The zone whose pool is to be replaced

 * @param layer     The physical layer from which to make VIOs

 * @param poolSize  The size of the new pool

 *

 * @return VDO_SUCCESS or an error

 **/

int replaceTreeZoneVIOPool(BlockMapTreeZone *zone,

                           PhysicalLayer    *layer,

                           size_t            poolSize)

  __attribute__((warn_unused_result));

/**

 * Check whether a buffer contains a valid page. If the page is bad, log an

 * error. If the page is valid, copy it to the supplied page.

 *

 * @param buffer  The buffer to validate (and copy)

 * @param nonce   The VDO nonce

 * @param pbn     The absolute PBN of the page

 * @param page    The page to copy into if valid

 *

 * @return true if the page was copied (valid)

 **/

bool copyValidPage(char                *buffer,

                   Nonce                nonce,

                   PhysicalBlockNumber  pbn,

                   BlockMapPage        *page);

#endif // BLOCK_MAP_TREE_INTERNALS_H