/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */
/*
 * Copyright (c) 2018 by Delphix. All rights reserved.
 */

#ifndef _SYS_FS_ZFS_RLOCK_H
#define _SYS_FS_ZFS_RLOCK_H

#ifdef  __cplusplus
extern "C" {
#endif

typedef enum {
        RL_READER,
        RL_WRITER,
        RL_APPEND
} rangelock_type_t;

struct locked_range;

typedef void (rangelock_cb_t)(struct locked_range *, void *);

typedef struct rangelock {
        avl_tree_t rl_tree; /* contains locked_range_t */
        kmutex_t rl_lock;
        rangelock_cb_t *rl_cb;
        void *rl_arg;
} rangelock_t;

typedef struct locked_range {
        rangelock_t *lr_rangelock; /* rangelock that this lock applies to */
        avl_node_t lr_node;     /* avl node link */
        uint64_t lr_offset;     /* file range offset */
        uint64_t lr_length;     /* file range length */
        uint_t lr_count;        /* range reference count in tree */
        rangelock_type_t lr_type; /* range type */
        kcondvar_t lr_write_cv; /* cv for waiting writers */
        kcondvar_t lr_read_cv;  /* cv for waiting readers */
        uint8_t lr_proxy;       /* acting for original range */
        uint8_t lr_write_wanted; /* writer wants to lock this range */
        uint8_t lr_read_wanted; /* reader wants to lock this range */
} locked_range_t;

void rangelock_init(rangelock_t *, rangelock_cb_t *, void *);
void rangelock_fini(rangelock_t *);

locked_range_t *rangelock_enter(rangelock_t *,
    uint64_t, uint64_t, rangelock_type_t);
void rangelock_exit(locked_range_t *);
void rangelock_reduce(locked_range_t *, uint64_t, uint64_t);

#ifdef  __cplusplus
}
#endif

#endif  /* _SYS_FS_ZFS_RLOCK_H */