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 http://www.opensolaris.org/os/licensing. 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 #ifndef _SYS_FS_ZFS_RLOCK_H 27 #define _SYS_FS_ZFS_RLOCK_H 28 29 #pragma ident "%Z%%M% %I% %E% SMI" 30 31 #ifdef __cplusplus 32 extern "C" { 33 #endif 34 35 #ifdef _KERNEL 36 37 #include <sys/zfs_znode.h> 38 39 typedef enum { 40 RL_READER, 41 RL_WRITER, 42 RL_APPEND 43 } rl_type_t; 44 45 typedef struct rl { 46 avl_node_t r_node; /* avl node link */ 47 uint64_t r_off; /* file range offset */ 48 uint64_t r_len; /* file range length */ 49 uint_t r_cnt; /* range reference count in tree */ 50 rl_type_t r_type; /* range type */ 51 kcondvar_t r_wr_cv; /* cv for waiting writers */ 52 kcondvar_t r_rd_cv; /* cv for waiting readers */ 53 uint8_t r_proxy; /* acting for original range */ 54 uint8_t r_write_wanted; /* writer wants to lock this range */ 55 uint8_t r_read_wanted; /* reader wants to lock this range */ 56 } rl_t; 57 58 /* 59 * Lock a range (offset, length) as either shared (READER) 60 * or exclusive (WRITER or APPEND). APPEND is a special type that 61 * is converted to WRITER that specified to lock from the start of the 62 * end of file. zfs_range_lock() returns the range lock structure. 63 */ 64 rl_t *zfs_range_lock(znode_t *zp, uint64_t off, uint64_t len, rl_type_t type); 65 66 /* 67 * Unlock range and destroy range lock structure. 68 */ 69 void zfs_range_unlock(znode_t *zp, rl_t *rl); 70 71 /* 72 * Reduce range locked as RW_WRITER from whole file to specified range. 73 * Asserts the whole file was previously locked. 74 */ 75 void zfs_range_reduce(znode_t *zp, rl_t *rl, uint64_t off, uint64_t len); 76 77 /* 78 * AVL comparison function used to compare range locks 79 */ 80 int zfs_range_compare(const void *arg1, const void *arg2); 81 82 #endif /* _KERNEL */ 83 84 #ifdef __cplusplus 85 } 86 #endif 87 88 #endif /* _SYS_FS_ZFS_RLOCK_H */ 89