| 1 | /* $NetBSD: null_vfsops.c,v 1.90 2014/11/09 18:08:07 maxv 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 1.90 2014/11/09 18:08:07 maxv 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/module.h> |
| 88 | |
| 89 | #include <miscfs/nullfs/null.h> |
| 90 | #include <miscfs/genfs/layer_extern.h> |
| 91 | |
| 92 | MODULE(MODULE_CLASS_VFS, null, "layerfs" ); |
| 93 | |
| 94 | VFS_PROTOS(nullfs); |
| 95 | |
| 96 | static struct sysctllog *nullfs_sysctl_log; |
| 97 | |
| 98 | int |
| 99 | nullfs_mount(struct mount *mp, const char *path, void *data, size_t *data_len) |
| 100 | { |
| 101 | struct vnode *lowerrootvp, *vp; |
| 102 | struct null_args *args = data; |
| 103 | struct null_mount *nmp; |
| 104 | struct layer_mount *lmp; |
| 105 | struct pathbuf *pb; |
| 106 | struct nameidata nd; |
| 107 | int error; |
| 108 | |
| 109 | if (args == NULL) |
| 110 | return EINVAL; |
| 111 | if (*data_len < sizeof(*args)) |
| 112 | return EINVAL; |
| 113 | |
| 114 | if (mp->mnt_flag & MNT_GETARGS) { |
| 115 | lmp = MOUNTTOLAYERMOUNT(mp); |
| 116 | if (lmp == NULL) |
| 117 | return EIO; |
| 118 | args->la.target = NULL; |
| 119 | *data_len = sizeof(*args); |
| 120 | return 0; |
| 121 | } |
| 122 | |
| 123 | /* Update is not supported. */ |
| 124 | if (mp->mnt_flag & MNT_UPDATE) |
| 125 | return EOPNOTSUPP; |
| 126 | |
| 127 | /* Find the lower vnode and lock it. */ |
| 128 | error = pathbuf_copyin(args->la.target, &pb); |
| 129 | if (error) { |
| 130 | return error; |
| 131 | } |
| 132 | NDINIT(&nd, LOOKUP, FOLLOW|LOCKLEAF, pb); |
| 133 | if ((error = namei(&nd)) != 0) { |
| 134 | pathbuf_destroy(pb); |
| 135 | return error; |
| 136 | } |
| 137 | lowerrootvp = nd.ni_vp; |
| 138 | pathbuf_destroy(pb); |
| 139 | |
| 140 | /* Create the mount point. */ |
| 141 | nmp = kmem_zalloc(sizeof(struct null_mount), KM_SLEEP); |
| 142 | mp->mnt_data = nmp; |
| 143 | nmp->nullm_vfs = lowerrootvp->v_mount; |
| 144 | if (nmp->nullm_vfs->mnt_flag & MNT_LOCAL) |
| 145 | mp->mnt_flag |= MNT_LOCAL; |
| 146 | |
| 147 | /* |
| 148 | * Make sure that the mount point is sufficiently initialized |
| 149 | * that the node create call will work. |
| 150 | */ |
| 151 | vfs_getnewfsid(mp); |
| 152 | |
| 153 | nmp->nullm_size = sizeof(struct null_node); |
| 154 | nmp->nullm_tag = VT_NULL; |
| 155 | nmp->nullm_bypass = layer_bypass; |
| 156 | nmp->nullm_vnodeop_p = null_vnodeop_p; |
| 157 | |
| 158 | /* Setup a null node for root vnode. */ |
| 159 | VOP_UNLOCK(lowerrootvp); |
| 160 | error = layer_node_create(mp, lowerrootvp, &vp); |
| 161 | if (error) { |
| 162 | vrele(lowerrootvp); |
| 163 | kmem_free(nmp, sizeof(struct null_mount)); |
| 164 | return error; |
| 165 | } |
| 166 | /* |
| 167 | * Keep a held reference to the root vnode. It will be released on |
| 168 | * umount. Note: nullfs is MP-safe. |
| 169 | */ |
| 170 | vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); |
| 171 | vp->v_vflag |= VV_ROOT; |
| 172 | nmp->nullm_rootvp = vp; |
| 173 | mp->mnt_iflag |= IMNT_MPSAFE; |
| 174 | VOP_UNLOCK(vp); |
| 175 | |
| 176 | error = set_statvfs_info(path, UIO_USERSPACE, args->la.target, |
| 177 | UIO_USERSPACE, mp->mnt_op->vfs_name, mp, curlwp); |
| 178 | return error; |
| 179 | } |
| 180 | |
| 181 | int |
| 182 | nullfs_unmount(struct mount *mp, int mntflags) |
| 183 | { |
| 184 | struct null_mount *nmp = MOUNTTONULLMOUNT(mp); |
| 185 | struct vnode *null_rootvp = nmp->nullm_rootvp; |
| 186 | int error, flags = 0; |
| 187 | |
| 188 | if (mntflags & MNT_FORCE) |
| 189 | flags |= FORCECLOSE; |
| 190 | |
| 191 | if (null_rootvp->v_usecount > 1 && (mntflags & MNT_FORCE) == 0) |
| 192 | return EBUSY; |
| 193 | |
| 194 | if ((error = vflush(mp, null_rootvp, flags)) != 0) |
| 195 | return error; |
| 196 | |
| 197 | /* Eliminate all activity and release the vnode. */ |
| 198 | vgone(null_rootvp); |
| 199 | |
| 200 | /* Finally, destroy the mount point structures. */ |
| 201 | kmem_free(mp->mnt_data, sizeof(struct null_mount)); |
| 202 | mp->mnt_data = NULL; |
| 203 | return 0; |
| 204 | } |
| 205 | |
| 206 | extern const struct vnodeopv_desc null_vnodeop_opv_desc; |
| 207 | |
| 208 | const struct vnodeopv_desc * const nullfs_vnodeopv_descs[] = { |
| 209 | &null_vnodeop_opv_desc, |
| 210 | NULL, |
| 211 | }; |
| 212 | |
| 213 | struct vfsops nullfs_vfsops = { |
| 214 | .vfs_name = MOUNT_NULL, |
| 215 | .vfs_min_mount_data = sizeof (struct null_args), |
| 216 | .vfs_mount = nullfs_mount, |
| 217 | .vfs_start = layerfs_start, |
| 218 | .vfs_unmount = nullfs_unmount, |
| 219 | .vfs_root = layerfs_root, |
| 220 | .vfs_quotactl = layerfs_quotactl, |
| 221 | .vfs_statvfs = layerfs_statvfs, |
| 222 | .vfs_sync = layerfs_sync, |
| 223 | .vfs_loadvnode = layerfs_loadvnode, |
| 224 | .vfs_vget = layerfs_vget, |
| 225 | .vfs_fhtovp = layerfs_fhtovp, |
| 226 | .vfs_vptofh = layerfs_vptofh, |
| 227 | .vfs_init = layerfs_init, |
| 228 | .vfs_done = layerfs_done, |
| 229 | .vfs_snapshot = layerfs_snapshot, |
| 230 | .vfs_extattrctl = vfs_stdextattrctl, |
| 231 | .vfs_suspendctl = (void *)eopnotsupp, |
| 232 | .vfs_renamelock_enter = layerfs_renamelock_enter, |
| 233 | .vfs_renamelock_exit = layerfs_renamelock_exit, |
| 234 | .vfs_fsync = (void *)eopnotsupp, |
| 235 | .vfs_opv_descs = nullfs_vnodeopv_descs |
| 236 | }; |
| 237 | |
| 238 | static int |
| 239 | null_modcmd(modcmd_t cmd, void *arg) |
| 240 | { |
| 241 | int error; |
| 242 | |
| 243 | switch (cmd) { |
| 244 | case MODULE_CMD_INIT: |
| 245 | error = vfs_attach(&nullfs_vfsops); |
| 246 | if (error != 0) |
| 247 | break; |
| 248 | sysctl_createv(&nullfs_sysctl_log, 0, NULL, NULL, |
| 249 | CTLFLAG_PERMANENT, |
| 250 | CTLTYPE_NODE, "null" , |
| 251 | SYSCTL_DESCR("Loopback file system" ), |
| 252 | NULL, 0, NULL, 0, |
| 253 | CTL_VFS, 9, CTL_EOL); |
| 254 | /* |
| 255 | * XXX the "9" above could be dynamic, thereby eliminating |
| 256 | * one more instance of the "number to vfs" mapping problem, |
| 257 | * but "9" is the order as taken from sys/mount.h |
| 258 | */ |
| 259 | break; |
| 260 | case MODULE_CMD_FINI: |
| 261 | error = vfs_detach(&nullfs_vfsops); |
| 262 | if (error != 0) |
| 263 | break; |
| 264 | sysctl_teardown(&nullfs_sysctl_log); |
| 265 | break; |
| 266 | default: |
| 267 | error = ENOTTY; |
| 268 | break; |
| 269 | } |
| 270 | return error; |
| 271 | } |
| 272 | |