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
nbl_start_crit(vnode_t * vp,krw_t mode)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
nbl_end_crit(vnode_t * vp)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
nbl_in_crit(vnode_t * vp)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
nbl_need_check(vnode_t * vp)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
nbl_conflict(vnode_t * vp,nbl_op_t op,u_offset_t offset,ssize_t length,int svmand,caller_context_t * ct)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
nbl_svmand(vnode_t * vp,cred_t * cr,int * svp)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