/*

 * 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/hashLock.h#3 $

 */

#ifndef HASH_LOCK_H

#define HASH_LOCK_H

#include "types.h"

/**

 * Get the PBN lock on the duplicate data location for a DataVIO from the

 * HashLock the DataVIO holds (if there is one).

 *

 * @param dataVIO  The DataVIO to query

 *

 * @return The PBN lock on the DataVIO's duplicate location

 **/

PBNLock *getDuplicateLock(DataVIO *dataVIO)

  __attribute__((warn_unused_result));

/**

 * Acquire or share a lock on the hash (chunk name) of the data in a DataVIO,

 * updating the DataVIO to reference the lock. This must only be called in the

 * correct thread for the zone. In the unlikely case of a hash collision, this

 * function will succeed, but the DataVIO will not get a lock reference.

 *

 * @param dataVIO  The DataVIO acquiring a lock on its chunk name

 **/

int acquireHashLock(DataVIO *dataVIO)

  __attribute__((warn_unused_result));

/**

 * Asynchronously process a DataVIO that has just acquired its reference to a

 * hash lock. This may place the DataVIO on a wait queue, or it may use the

 * DataVIO to perform operations on the lock's behalf.

 *

 * @param dataVIO  The DataVIO that has just acquired a lock on its chunk name

 **/

void enterHashLock(DataVIO *dataVIO);

/**

 * Asynchronously continue processing a DataVIO in its hash lock after it has

 * finished writing, compressing, or deduplicating, so it can share the result

 * with any DataVIOs waiting in the hash lock, or update Albireo, or simply

 * release its share of the lock. This must only be called in the correct

 * thread for the hash zone.

 *

 * @param dataVIO  The DataVIO to continue processing in its hash lock

 **/

void continueHashLock(DataVIO *dataVIO);

/**

 * Re-enter the hash lock after encountering an error, to clean up the hash

 * lock.

 *

 * @param dataVIO  The DataVIO with an error

 **/

void continueHashLockOnError(DataVIO *dataVIO);

/**

 * Release a DataVIO's share of a hash lock, if held, and null out the

 * DataVIO's reference to it. This must only be called in the correct thread

 * for the hash zone.

 *

 * If the DataVIO is the only one holding the lock, this also releases any

 * resources or locks used by the hash lock (such as a PBN read lock on a

 * block containing data with the same hash) and returns the lock to the hash

 * zone's lock pool.

 *

 * @param dataVIO  The DataVIO releasing its hash lock

 **/

void releaseHashLock(DataVIO *dataVIO);

/**

 * Make a DataVIO's hash lock a shared holder of the PBN lock on the

 * compressed block to which its data was just written. If the lock is still a

 * write lock (as it will be for the first share), it will be converted to a

 * read lock. This also reserves a reference count increment for the DataVIO.

 *

 * @param dataVIO  The DataVIO which was just compressed

 * @param pbnLock  The PBN lock on the compressed block

 **/

void shareCompressedWriteLock(DataVIO *dataVIO, PBNLock *pbnLock);

#endif // HASH_LOCK_H