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 | |