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