include/sys/zfs_rlock.h

   1 /*
   2  * CDDL HEADER START
   3  *
   4  * The contents of this file are subject to the terms of the
   5  * Common Development and Distribution License (the "License").
   6  * You may not use this file except in compliance with the License.
   7  *
   8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
   9  * or https://opensource.org/licenses/CDDL-1.0.
  10  * See the License for the specific language governing permissions
  11  * and limitations under the License.
  12  *
  13  * When distributing Covered Code, include this CDDL HEADER in each
  14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  15  * If applicable, add the following below this CDDL HEADER, with the
  16  * fields enclosed by brackets "[]" replaced with your own identifying
  17  * information: Portions Copyright [yyyy] [name of copyright owner]
  18  *
  19  * CDDL HEADER END
  20  */
  21 /*
  22  * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
  23  * Use is subject to license terms.
  24  */
  25 /*
  26  * Copyright (c) 2018 by Delphix. All rights reserved.
  27  */
  28
  29 #ifndef _SYS_FS_ZFS_RLOCK_H
  30 #define _SYS_FS_ZFS_RLOCK_H
  31
  32 #ifdef  __cplusplus
  33 extern "C" {
  34 #endif
  35
  36 #include <sys/avl.h>
  37
  38 typedef enum {
  39         RL_READER,
  40         RL_WRITER,
  41         RL_APPEND
  42 } zfs_rangelock_type_t;
  43
  44 struct zfs_locked_range;
  45
  46 typedef void (zfs_rangelock_cb_t)(struct zfs_locked_range *, void *);
  47
  48 typedef struct zfs_rangelock {
  49         avl_tree_t rl_tree; /* contains locked_range_t */
  50         kmutex_t rl_lock;
  51         zfs_rangelock_cb_t *rl_cb;
  52         void *rl_arg;
  53 } zfs_rangelock_t;
  54
  55 typedef struct zfs_locked_range {
  56         zfs_rangelock_t *lr_rangelock; /* rangelock that this lock applies to */
  57         avl_node_t lr_node;     /* avl node link */
  58         uint64_t lr_offset;     /* file range offset */
  59         uint64_t lr_length;     /* file range length */
  60         uint_t lr_count;        /* range reference count in tree */
  61         zfs_rangelock_type_t lr_type; /* range type */
  62         kcondvar_t lr_write_cv; /* cv for waiting writers */
  63         kcondvar_t lr_read_cv;  /* cv for waiting readers */
  64         uint8_t lr_proxy;       /* acting for original range */
  65         uint8_t lr_write_wanted; /* writer wants to lock this range */
  66         uint8_t lr_read_wanted; /* reader wants to lock this range */
  67 } zfs_locked_range_t;
  68
  69 void zfs_rangelock_init(zfs_rangelock_t *, zfs_rangelock_cb_t *, void *);
  70 void zfs_rangelock_fini(zfs_rangelock_t *);
  71
  72 zfs_locked_range_t *zfs_rangelock_enter(zfs_rangelock_t *,
  73     uint64_t, uint64_t, zfs_rangelock_type_t);
  74 zfs_locked_range_t *zfs_rangelock_tryenter(zfs_rangelock_t *,
  75     uint64_t, uint64_t, zfs_rangelock_type_t);
  76 void zfs_rangelock_exit(zfs_locked_range_t *);
  77 void zfs_rangelock_reduce(zfs_locked_range_t *, uint64_t, uint64_t);
  78
  79 #ifdef  __cplusplus
  80 }
  81 #endif
  82
  83 #endif  /* _SYS_FS_ZFS_RLOCK_H */