null_vfsops.c revision 1.82
1/* $NetBSD: null_vfsops.c,v 1.82 2010/07/02 03:16:01 rmind Exp $ */ 2 3/* 4 * Copyright (c) 1999 National Aeronautics & Space Administration 5 * All rights reserved. 6 * 7 * This software was written by William Studenmund of the 8 * Numerical Aerospace Simulation Facility, NASA Ames Research Center. 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 National Aeronautics & Space Administration 19 * nor the names of its contributors may be used to endorse or promote 20 * products derived from this software without specific prior written 21 * permission. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE NATIONAL AERONAUTICS & SPACE ADMINISTRATION 24 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 25 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 26 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE ADMINISTRATION OR CONTRIB- 27 * UTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, 28 * OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 29 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 30 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 31 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 32 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 33 * POSSIBILITY OF SUCH DAMAGE. 34 */ 35 36/* 37 * Copyright (c) 1992, 1993, 1995 38 * The Regents of the University of California. All rights reserved. 39 * 40 * This code is derived from software donated to Berkeley by 41 * Jan-Simon Pendry. 42 * 43 * Redistribution and use in source and binary forms, with or without 44 * modification, are permitted provided that the following conditions 45 * are met: 46 * 1. Redistributions of source code must retain the above copyright 47 * notice, this list of conditions and the following disclaimer. 48 * 2. Redistributions in binary form must reproduce the above copyright 49 * notice, this list of conditions and the following disclaimer in the 50 * documentation and/or other materials provided with the distribution. 51 * 3. Neither the name of the University nor the names of its contributors 52 * may be used to endorse or promote products derived from this software 53 * without specific prior written permission. 54 * 55 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 56 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 57 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 58 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 59 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 60 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 61 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 62 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 63 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 64 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 65 * SUCH DAMAGE. 66 * 67 * from: Id: lofs_vfsops.c,v 1.9 1992/05/30 10:26:24 jsp Exp 68 * from: @(#)lofs_vfsops.c 1.2 (Berkeley) 6/18/92 69 * @(#)null_vfsops.c 8.7 (Berkeley) 5/14/95 70 */ 71 72/* 73 * Null file-system: VFS operations. 74 * 75 * See null_vnops.c for a description. 76 */ 77 78#include <sys/cdefs.h> 79__KERNEL_RCSID(0, "$NetBSD: null_vfsops.c,v 1.82 2010/07/02 03:16:01 rmind Exp $"); 80 81#include <sys/param.h> 82#include <sys/systm.h> 83#include <sys/sysctl.h> 84#include <sys/vnode.h> 85#include <sys/mount.h> 86#include <sys/namei.h> 87#include <sys/malloc.h> 88#include <sys/module.h> 89 90#include <miscfs/nullfs/null.h> 91#include <miscfs/genfs/layer_extern.h> 92 93MODULE(MODULE_CLASS_VFS, null, "layerfs"); 94 95VFS_PROTOS(nullfs); 96 97static struct sysctllog *nullfs_sysctl_log; 98 99int 100nullfs_mount(struct mount *mp, const char *path, void *data, size_t *data_len) 101{ 102 struct vnode *lowerrootvp, *vp; 103 struct null_args *args = data; 104 struct null_mount *nmp; 105 struct layer_mount *lmp; 106 struct nameidata nd; 107 int error; 108 109 if (*data_len < sizeof(*args)) 110 return EINVAL; 111 112 if (mp->mnt_flag & MNT_GETARGS) { 113 lmp = MOUNTTOLAYERMOUNT(mp); 114 if (lmp == NULL) 115 return EIO; 116 args->la.target = NULL; 117 *data_len = sizeof(*args); 118 return 0; 119 } 120 121 /* Update is not supported. */ 122 if (mp->mnt_flag & MNT_UPDATE) 123 return EOPNOTSUPP; 124 125 /* Find the lower vnode and lock it. */ 126 NDINIT(&nd, LOOKUP, FOLLOW|LOCKLEAF, UIO_USERSPACE, args->la.target); 127 if ((error = namei(&nd)) != 0) { 128 return error; 129 } 130 lowerrootvp = nd.ni_vp; 131 132 /* Create the mount point. */ 133 nmp = malloc(sizeof(struct null_mount), M_UFSMNT, M_WAITOK | M_ZERO); 134 mp->mnt_data = nmp; 135 nmp->nullm_vfs = lowerrootvp->v_mount; 136 if (nmp->nullm_vfs->mnt_flag & MNT_LOCAL) 137 mp->mnt_flag |= MNT_LOCAL; 138 139 /* 140 * Make sure that the mount point is sufficiently initialized 141 * that the node create call will work. 142 */ 143 vfs_getnewfsid(mp); 144 145 nmp->nullm_size = sizeof(struct null_node); 146 nmp->nullm_tag = VT_NULL; 147 nmp->nullm_bypass = layer_bypass; 148 nmp->nullm_alloc = layer_node_alloc; /* the default alloc is fine */ 149 nmp->nullm_vnodeop_p = null_vnodeop_p; 150 mutex_init(&nmp->nullm_hashlock, MUTEX_DEFAULT, IPL_NONE); 151 nmp->nullm_node_hashtbl = hashinit(desiredvnodes, HASH_LIST, true, 152 &nmp->nullm_node_hash); 153 154 /* Setup a null node for root vnode. */ 155 error = layer_node_create(mp, lowerrootvp, &vp); 156 if (error) { 157 vput(lowerrootvp); 158 hashdone(nmp->nullm_node_hashtbl, HASH_LIST, 159 nmp->nullm_node_hash); 160 free(nmp, M_UFSMNT); 161 return error; 162 } 163 /* 164 * Keep a held reference to the root vnode. It will be released on 165 * umount. Note: nullfs is MP-safe. 166 */ 167 vp->v_vflag |= VV_ROOT; 168 nmp->nullm_rootvp = vp; 169 mp->mnt_iflag |= IMNT_MPSAFE; 170 VOP_UNLOCK(vp); 171 172 error = set_statvfs_info(path, UIO_USERSPACE, args->la.target, 173 UIO_USERSPACE, mp->mnt_op->vfs_name, mp, curlwp); 174 return error; 175} 176 177int 178nullfs_unmount(struct mount *mp, int mntflags) 179{ 180 struct null_mount *nmp = MOUNTTONULLMOUNT(mp); 181 struct vnode *null_rootvp = nmp->nullm_rootvp; 182 int error, flags = 0; 183 184 if (mntflags & MNT_FORCE) 185 flags |= FORCECLOSE; 186 187 if (null_rootvp->v_usecount > 1 && (mntflags & MNT_FORCE) == 0) 188 return EBUSY; 189 190 if ((error = vflush(mp, null_rootvp, flags)) != 0) 191 return error; 192 193 /* Eliminate all activity and release the vnode. */ 194 vgone(null_rootvp); 195 196 /* Finally, destroy the mount point structures. */ 197 hashdone(nmp->nullm_node_hashtbl, HASH_LIST, nmp->nullm_node_hash); 198 mutex_destroy(&nmp->nullm_hashlock); 199 free(mp->mnt_data, M_UFSMNT); 200 mp->mnt_data = NULL; 201 return 0; 202} 203 204extern const struct vnodeopv_desc null_vnodeop_opv_desc; 205 206const struct vnodeopv_desc * const nullfs_vnodeopv_descs[] = { 207 &null_vnodeop_opv_desc, 208 NULL, 209}; 210 211struct vfsops nullfs_vfsops = { 212 MOUNT_NULL, 213 sizeof (struct null_args), 214 nullfs_mount, 215 layerfs_start, 216 nullfs_unmount, 217 layerfs_root, 218 layerfs_quotactl, 219 layerfs_statvfs, 220 layerfs_sync, 221 layerfs_vget, 222 layerfs_fhtovp, 223 layerfs_vptofh, 224 layerfs_init, 225 NULL, 226 layerfs_done, 227 NULL, /* vfs_mountroot */ 228 layerfs_snapshot, 229 vfs_stdextattrctl, 230 (void *)eopnotsupp, /* vfs_suspendctl */ 231 layerfs_renamelock_enter, 232 layerfs_renamelock_exit, 233 (void *)eopnotsupp, 234 nullfs_vnodeopv_descs, 235 0, 236 { NULL, NULL }, 237}; 238 239static int 240null_modcmd(modcmd_t cmd, void *arg) 241{ 242 int error; 243 244 switch (cmd) { 245 case MODULE_CMD_INIT: 246 error = vfs_attach(&nullfs_vfsops); 247 if (error != 0) 248 break; 249 sysctl_createv(&nullfs_sysctl_log, 0, NULL, NULL, 250 CTLFLAG_PERMANENT, 251 CTLTYPE_NODE, "vfs", NULL, 252 NULL, 0, NULL, 0, 253 CTL_VFS, CTL_EOL); 254 sysctl_createv(&nullfs_sysctl_log, 0, NULL, NULL, 255 CTLFLAG_PERMANENT, 256 CTLTYPE_NODE, "null", 257 SYSCTL_DESCR("Loopback file system"), 258 NULL, 0, NULL, 0, 259 CTL_VFS, 9, CTL_EOL); 260 /* 261 * XXX the "9" above could be dynamic, thereby eliminating 262 * one more instance of the "number to vfs" mapping problem, 263 * but "9" is the order as taken from sys/mount.h 264 */ 265 break; 266 case MODULE_CMD_FINI: 267 error = vfs_detach(&nullfs_vfsops); 268 if (error != 0) 269 break; 270 sysctl_teardown(&nullfs_sysctl_log); 271 break; 272 default: 273 error = ENOTTY; 274 break; 275 } 276 return error; 277} 278