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/*
* 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.
*/
#ifndef _SYS_FS_ZFS_RLOCK_H
#define _SYS_FS_ZFS_RLOCK_H
#ifdef __cplusplus
extern "C" {
#endif
#include <sys/list.h>
#include <sys/avl.h>
#ifdef _KERNEL
#include <sys/condvar.h>
#else
#include <sys/zfs_context.h>
#endif
typedef enum {
RL_READER,
RL_WRITER,
RL_APPEND
} rl_type_t;
typedef struct zfs_rlock {
kmutex_t zr_mutex; /* protects changes to zr_avl */
avl_tree_t zr_avl; /* avl tree of range locks */
uint64_t *zr_size; /* points to znode->z_size */
uint_t *zr_blksz; /* points to znode->z_blksz */
uint64_t *zr_max_blksz; /* points to zfsvfs->z_max_blksz */
} zfs_rlock_t;
typedef struct rl {
zfs_rlock_t *r_zrl;
avl_node_t r_node; /* avl node link */
uint64_t r_off; /* file range offset */
uint64_t r_len; /* file range length */
uint_t r_cnt; /* range reference count in tree */
rl_type_t r_type; /* range type */
kcondvar_t r_wr_cv; /* cv for waiting writers */
kcondvar_t r_rd_cv; /* cv for waiting readers */
uint8_t r_proxy; /* acting for original range */
uint8_t r_write_wanted; /* writer wants to lock this range */
uint8_t r_read_wanted; /* reader wants to lock this range */
list_node_t rl_node; /* used for deferred release */
} rl_t;
/*
* Lock a range (offset, length) as either shared (RL_READER)
* or exclusive (RL_WRITER or RL_APPEND). RL_APPEND is a special type that
* is converted to RL_WRITER that specified to lock from the start of the
* end of file. Returns the range lock structure.
*/
rl_t *zfs_range_lock(zfs_rlock_t *zrl, uint64_t off, uint64_t len,
rl_type_t type);
/* Unlock range and destroy range lock structure. */
void zfs_range_unlock(rl_t *rl);
/*
* Reduce range locked as RW_WRITER from whole file to specified range.
* Asserts the whole file was previously locked.
*/
void zfs_range_reduce(rl_t *rl, uint64_t off, uint64_t len);
/*
* AVL comparison function used to order range locks
* Locks are ordered on the start offset of the range.
*/
int zfs_range_compare(const void *arg1, const void *arg2);
static inline void
zfs_rlock_init(zfs_rlock_t *zrl)
{
mutex_init(&zrl->zr_mutex, NULL, MUTEX_DEFAULT, NULL);
avl_create(&zrl->zr_avl, zfs_range_compare,
sizeof (rl_t), offsetof(rl_t, r_node));
zrl->zr_size = NULL;
zrl->zr_blksz = NULL;
zrl->zr_max_blksz = NULL;
}
static inline void
zfs_rlock_destroy(zfs_rlock_t *zrl)
{
avl_destroy(&zrl->zr_avl);
mutex_destroy(&zrl->zr_mutex);
}
#ifdef __cplusplus
}
#endif
#endif /* _SYS_FS_ZFS_RLOCK_H */
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