/*

 * 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/recoveryUtils.h#5 $

 */

#ifndef RECOVERY_UTILS_H

#define RECOVERY_UTILS_H

#include "constants.h"

#include "packedRecoveryJournalBlock.h"

#include "recoveryJournalEntry.h"

#include "recoveryJournalInternals.h"

#include "types.h"

/**

 * Get the block header for a block at a position in the journal data.

 *

 * @param journal      The recovery journal

 * @param journalData  The recovery journal data

 * @param sequence     The sequence number

 *

 * @return A pointer to a packed recovery journal block header.

 **/

__attribute__((warn_unused_result))

static inline

PackedJournalHeader *getJournalBlockHeader(RecoveryJournal *journal,

                                           char            *journalData,

                                           SequenceNumber   sequence)

{

  off_t blockOffset = (getRecoveryJournalBlockNumber(journal, sequence)

                       * VDO_BLOCK_SIZE);

  return (PackedJournalHeader *) &journalData[blockOffset];

}

/**

 * Determine whether the given header describes a valid block for the

 * given journal. A block is not valid if it is unformatted, or if it

 * is older than the last successful recovery or reformat.

 *

 * @param journal  The journal to use

 * @param header   The unpacked block header to check

 *

 * @return True if the header is valid

 **/

__attribute__((warn_unused_result))

static inline

bool isValidRecoveryJournalBlock(const RecoveryJournal     *journal,

                                 const RecoveryBlockHeader *header)

{

  return ((header->metadataType == VDO_METADATA_RECOVERY_JOURNAL)

          && (header->nonce == journal->nonce)

          && (header->recoveryCount == journal->recoveryCount));

}

/**

 * Determine whether the given header describes the exact block indicated.

 *

 * @param journal   The journal to use

 * @param header    The unpacked block header to check

 * @param sequence  The expected sequence number

 *

 * @return True if the block matches

 **/

__attribute__((warn_unused_result))

static inline

bool isExactRecoveryJournalBlock(const RecoveryJournal     *journal,

                                 const RecoveryBlockHeader *header,

                                 SequenceNumber             sequence)

{

  return ((header->sequenceNumber == sequence)

          && isValidRecoveryJournalBlock(journal, header));

}

/**

 * Determine whether the header of the given sector could describe a

 * valid sector for the given journal block header.

 *

 * @param header  The unpacked block header to compare against

 * @param sector  The packed sector to check

 *

 * @return True if the sector matches the block header

 **/

__attribute__((warn_unused_result))

static inline

bool isValidRecoveryJournalSector(const RecoveryBlockHeader *header,

                                  const PackedJournalSector *sector)

{

  return ((header->checkByte == sector->checkByte)

          && (header->recoveryCount == sector->recoveryCount));

}

/**

 * Load the journal data off the disk.

 *

 * @param [in]  journal         The recovery journal to load

 * @param [in]  parent          The completion to notify when the load is

 *                              complete

 * @param [out] journalDataPtr  A pointer to the journal data buffer (it is the

 *                              caller's responsibility to free this buffer)

 **/

void loadJournalAsync(RecoveryJournal  *journal,

                      VDOCompletion    *parent,

                      char            **journalDataPtr);

/**

 * Find the tail and the head of the journal by searching for the highest

 * sequence number in a block with a valid nonce, and the highest head value

 * among the blocks with valid nonces.

 *

 * @param [in]  journal             The recovery journal

 * @param [in]  journalData         The journal data read from disk

 * @param [out] tailPtr             A pointer to return the tail found, or if

 *                                  no higher block is found, the value

 *                                  currently in the journal

 * @param [out] blockMapHeadPtr     A pointer to return the block map head

 * @param [out] slabJournalHeadPtr  An optional pointer to return the slab

 *                                  journal head

 *

 * @return  True if there were valid journal blocks

 **/

bool findHeadAndTail(RecoveryJournal *journal,

                     char            *journalData,

                     SequenceNumber  *tailPtr,

                     SequenceNumber  *blockMapHeadPtr,

                     SequenceNumber  *slabJournalHeadPtr);

/**

 * Validate a recovery journal entry.

 *

 * @param vdo    The VDO

 * @param entry  The entry to validate

 *

 * @return VDO_SUCCESS or an error

 **/

int validateRecoveryJournalEntry(const VDO                  *vdo,

                                 const RecoveryJournalEntry *entry)

  __attribute__((warn_unused_result));

#endif // RECOVERY_UTILS_H