null.h (3328B) - Raw
1 /*- 2 * SPDX-License-Identifier: BSD-3-Clause 3 * 4 * Copyright (c) 1992, 1993 5 * The Regents of the University of California. All rights reserved. 6 * 7 * This code is derived from software donated to Berkeley by 8 * Jan-Simon Pendry. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. Neither the name of the University nor the names of its contributors 19 * may be used to endorse or promote products derived from this software 20 * without specific prior written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 * 34 * @(#)null.h 8.3 (Berkeley) 8/20/94 35 */ 36 37 #ifndef FS_NULL_H 38 #define FS_NULL_H 39 40 #define NULLM_CACHE 0x0001 41 42 struct null_mount { 43 struct mount *nullm_vfs; 44 struct vnode *nullm_lowerrootvp; /* Ref to lower root vnode */ 45 uint64_t nullm_flags; 46 struct mount_upper_node upper_node; 47 struct mount_upper_node notify_node; 48 }; 49 50 #ifdef _KERNEL 51 /* 52 * A cache of vnode references 53 */ 54 struct null_node { 55 LIST_ENTRY(null_node) null_hash; /* Hash list */ 56 struct vnode *null_lowervp; /* VREFed once */ 57 struct vnode *null_vnode; /* Back pointer */ 58 u_int null_flags; 59 }; 60 61 #define NULLV_NOUNLOCK 0x0001 62 #define NULLV_DROP 0x0002 63 64 #define MOUNTTONULLMOUNT(mp) ((struct null_mount *)((mp)->mnt_data)) 65 #define VTONULL(vp) ((struct null_node *)(vp)->v_data) 66 #define NULLTOV(xp) ((xp)->null_vnode) 67 68 int nullfs_init(struct vfsconf *vfsp); 69 int nullfs_uninit(struct vfsconf *vfsp); 70 int null_nodeget(struct mount *mp, struct vnode *target, struct vnode **vpp); 71 struct vnode *null_hashget(struct mount *mp, struct vnode *lowervp); 72 void null_hashrem(struct null_node *xp); 73 int null_bypass(struct vop_generic_args *ap); 74 75 #ifdef DIAGNOSTIC 76 struct vnode *null_checkvp(struct vnode *vp, char *fil, int lno); 77 #define NULLVPTOLOWERVP(vp) null_checkvp((vp), __FILE__, __LINE__) 78 #else 79 #define NULLVPTOLOWERVP(vp) (VTONULL(vp)->null_lowervp) 80 #endif 81 82 extern struct vop_vector null_vnodeops; 83 84 #ifdef MALLOC_DECLARE 85 MALLOC_DECLARE(M_NULLFSNODE); 86 #endif 87 88 #ifdef NULLFS_DEBUG 89 #define NULLFSDEBUG(format, args...) printf(format ,## args) 90 #else 91 #define NULLFSDEBUG(format, args...) 92 #endif /* NULLFS_DEBUG */ 93 94 #endif /* _KERNEL */ 95 96 #endif