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 2008 Sun Microsystems, Inc. All rights reserved. 23 * Use is subject to license terms. 24 * 25 * Copyright 2017 Nexenta Systems, Inc. All rights reserved. 26 */ 27 28 /* 29 * Utility routines and top-level conflict detection code for NBMAND 30 * locks. 31 */ 32 33 #include <sys/nbmlock.h> 34 #include <sys/rwlock.h> 35 #include <sys/vnode.h> 36 #include <sys/cmn_err.h> 37 #include <sys/debug.h> 38 #include <sys/types.h> 39 #include <sys/fcntl.h> 40 #include <sys/vfs.h> 41 42 /* 43 * Enter the critical region for synchronizing I/O requests with lock/share 44 * requests. "mode" specifies whether the caller intends to update 45 * lock/share state (as opposed to just query it). 46 */ 47 48 void 49 nbl_start_crit(vnode_t *vp, krw_t mode) 50 { 51 rw_enter(&vp->v_nbllock, mode); 52 } 53 54 /* 55 * Leave the critical region. 56 */ 57 58 void 59 nbl_end_crit(vnode_t *vp) 60 { 61 rw_exit(&vp->v_nbllock); 62 } 63 64 /* 65 * Return non-zero if some thread is in the critical region. 66 * Note that this is appropriate for use in ASSERT()s only. 67 */ 68 69 int 70 nbl_in_crit(vnode_t *vp) 71 { 72 return (RW_LOCK_HELD(&vp->v_nbllock)); 73 } 74 75 /* 76 * Returns non-zero if we need to look further for an NBMAND lock or 77 * share conflict. 78 */ 79 int 80 nbl_need_check(vnode_t *vp) 81 { 82 /* 83 * Currently we only check if NBMAND locks/shares are allowed on 84 * the filesystem. An option for the future would be to have a 85 * flag on the vnode, though the locking for that can get tricky. 86 */ 87 return ((vp->v_vfsp) && (vp->v_vfsp->vfs_flag & VFS_NBMAND)); 88 } 89 90 /* No locks, so no conflicts. */ 91 int 92 nbl_conflict(vnode_t *vp, 93 nbl_op_t op, /* attempted operation */ 94 u_offset_t offset, /* ignore if not I/O */ 95 ssize_t length, /* ignore if not I/O */ 96 int svmand, /* System V mandatory locking */ 97 caller_context_t *ct) /* caller context */ 98 { 99 ASSERT(nbl_in_crit(vp)); 100 101 return (0); 102 } 103 104 /* 105 * Determine if the given file has mode bits for System V mandatory locks. 106 * If there was an error, the errno value is returned. Otherwise, zero is 107 * returned and *svp is set appropriately (non-zero for mandatory locks, 108 * zero for no mandatory locks). 109 */ 110 111 int 112 nbl_svmand(vnode_t *vp, cred_t *cr, int *svp) 113 { 114 struct vattr va; 115 int error; 116 117 va.va_mask = AT_MODE; 118 error = VOP_GETATTR(vp, &va, 0, cr, NULL); 119 if (error != 0) 120 return (error); 121 122 *svp = MANDLOCK(vp, va.va_mode); 123 return (0); 124 } 125