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 35 #ifndef FS_NULL_H 36 #define FS_NULL_H 37 38 #define NULLM_CACHE 0x0001 39 40 struct null_mount { 41 struct mount *nullm_vfs; 42 struct vnode *nullm_lowerrootvp; /* Ref to lower root vnode */ 43 uint64_t nullm_flags; 44 struct mount_upper_node upper_node; 45 struct mount_upper_node notify_node; 46 }; 47 48 #ifdef _KERNEL 49 /* 50 * A cache of vnode references 51 */ 52 struct null_node { 53 LIST_ENTRY(null_node) null_hash; /* Hash list */ 54 struct vnode *null_lowervp; /* VREFed once */ 55 struct vnode *null_vnode; /* Back pointer */ 56 u_int null_flags; 57 }; 58 59 #define NULLV_NOUNLOCK 0x0001 60 #define NULLV_DROP 0x0002 61 62 #define MOUNTTONULLMOUNT(mp) ((struct null_mount *)((mp)->mnt_data)) 63 #define VTONULL(vp) ((struct null_node *)(vp)->v_data) 64 #define NULLTOV(xp) ((xp)->null_vnode) 65 66 int nullfs_init(struct vfsconf *vfsp); 67 int nullfs_uninit(struct vfsconf *vfsp); 68 int null_nodeget(struct mount *mp, struct vnode *target, struct vnode **vpp); 69 struct vnode *null_hashget(struct mount *mp, struct vnode *lowervp); 70 void null_hashrem(struct null_node *xp); 71 int null_bypass(struct vop_generic_args *ap); 72 73 #ifdef DIAGNOSTIC 74 struct vnode *null_checkvp(struct vnode *vp, char *fil, int lno); 75 #define NULLVPTOLOWERVP(vp) null_checkvp((vp), __FILE__, __LINE__) 76 #else 77 #define NULLVPTOLOWERVP(vp) (VTONULL(vp)->null_lowervp) 78 #endif 79 80 extern struct vop_vector null_vnodeops; 81 82 #ifdef MALLOC_DECLARE 83 MALLOC_DECLARE(M_NULLFSNODE); 84 #endif 85 86 #ifdef NULLFS_DEBUG 87 #define NULLFSDEBUG(format, args...) printf(format ,## args) 88 #else 89 #define NULLFSDEBUG(format, args...) 90 #endif /* NULLFS_DEBUG */ 91 92 #endif /* _KERNEL */ 93 94 #endif 95