Style(9):
[dragonfly.git] / sys / vfs / nullfs / null_vfsops.c
CommitLineData
984263bc
MD
1/*
2 * Copyright (c) 1992, 1993, 1995
3 * The Regents of the University of California. All rights reserved.
4 *
5 * This code is derived from software donated to Berkeley by
6 * Jan-Simon Pendry.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 * 3. All advertising materials mentioning features or use of this software
17 * must display the following acknowledgement:
18 * This product includes software developed by the University of
19 * California, Berkeley and its contributors.
20 * 4. Neither the name of the University nor the names of its contributors
21 * may be used to endorse or promote products derived from this software
22 * without specific prior written permission.
23 *
24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34 * SUCH DAMAGE.
35 *
36 * @(#)null_vfsops.c 8.2 (Berkeley) 1/21/94
37 *
38 * @(#)lofs_vfsops.c 1.2 (Berkeley) 6/18/92
39 * $FreeBSD: src/sys/miscfs/nullfs/null_vfsops.c,v 1.35.2.3 2001/07/26 20:37:11 iedowse Exp $
5fd012e0 40 * $DragonFly: src/sys/vfs/nullfs/null_vfsops.c,v 1.13 2004/10/12 19:21:04 dillon Exp $
984263bc
MD
41 */
42
43/*
44 * Null Layer
45 * (See null_vnops.c for a description of what this does.)
46 */
47
48#include <sys/param.h>
49#include <sys/systm.h>
50#include <sys/kernel.h>
51#include <sys/proc.h>
52#include <sys/malloc.h>
53#include <sys/vnode.h>
54#include <sys/mount.h>
55#include <sys/namei.h>
1f2de5d4 56#include "null.h"
984263bc 57
0961aa92
MD
58extern struct vnodeopv_entry_desc null_vnodeop_entries[];
59
984263bc
MD
60static MALLOC_DEFINE(M_NULLFSMNT, "NULLFS mount", "NULLFS mount structure");
61
62static int nullfs_fhtovp(struct mount *mp, struct fid *fidp,
63 struct vnode **vpp);
64static int nullfs_checkexp(struct mount *mp, struct sockaddr *nam,
65 int *extflagsp, struct ucred **credanonp);
66static int nullfs_mount(struct mount *mp, char *path, caddr_t data,
21739618 67 struct thread *td);
984263bc 68static int nullfs_quotactl(struct mount *mp, int cmd, uid_t uid,
dadab5e9 69 caddr_t arg, struct thread *td);
984263bc 70static int nullfs_root(struct mount *mp, struct vnode **vpp);
dadab5e9 71static int nullfs_start(struct mount *mp, int flags, struct thread *td);
984263bc 72static int nullfs_statfs(struct mount *mp, struct statfs *sbp,
dadab5e9 73 struct thread *td);
3b568787 74static int nullfs_sync(struct mount *mp, int waitfor, struct thread *td);
dadab5e9 75static int nullfs_unmount(struct mount *mp, int mntflags, struct thread *td);
984263bc
MD
76static int nullfs_vget(struct mount *mp, ino_t ino, struct vnode **vpp);
77static int nullfs_vptofh(struct vnode *vp, struct fid *fhp);
78static int nullfs_extattrctl(struct mount *mp, int cmd,
dadab5e9 79 const char *attrname, caddr_t arg, struct thread *td);
984263bc
MD
80
81/*
82 * Mount null layer
83 */
84static int
21739618 85nullfs_mount(struct mount *mp, char *path, caddr_t data, struct thread *td)
984263bc
MD
86{
87 int error = 0;
88 struct null_args args;
89 struct vnode *lowerrootvp, *vp;
90 struct vnode *nullm_rootvp;
91 struct null_mount *xmp;
92 u_int size;
93 int isvnunlocked = 0;
21739618 94 struct nameidata nd;
984263bc
MD
95
96 NULLFSDEBUG("nullfs_mount(mp = %p)\n", (void *)mp);
97
98 /*
99 * Update is a no-op
100 */
101 if (mp->mnt_flag & MNT_UPDATE) {
102 return (EOPNOTSUPP);
984263bc
MD
103 }
104
105 /*
106 * Get argument
107 */
108 error = copyin(data, (caddr_t)&args, sizeof(struct null_args));
109 if (error)
110 return (error);
111
112 /*
113 * Unlock lower node to avoid deadlock.
114 * (XXX) VOP_ISLOCKED is needed?
115 */
0961aa92 116 if ((mp->mnt_vnodecovered->v_tag == VT_NULL) &&
984263bc 117 VOP_ISLOCKED(mp->mnt_vnodecovered, NULL)) {
5fd012e0 118 VOP_UNLOCK(mp->mnt_vnodecovered, 0, td);
984263bc
MD
119 isvnunlocked = 1;
120 }
121 /*
122 * Find lower node
123 */
21739618 124 NDINIT(&nd, NAMEI_LOOKUP, CNP_FOLLOW | CNP_WANTPARENT | CNP_LOCKLEAF,
dadab5e9 125 UIO_USERSPACE, args.target, td);
21739618 126 error = namei(&nd);
984263bc
MD
127 /*
128 * Re-lock vnode.
129 */
130 if (isvnunlocked && !VOP_ISLOCKED(mp->mnt_vnodecovered, NULL))
5fd012e0 131 vn_lock(mp->mnt_vnodecovered, LK_EXCLUSIVE | LK_RETRY, td);
984263bc
MD
132
133 if (error)
134 return (error);
21739618 135 NDFREE(&nd, NDF_ONLY_PNBUF);
984263bc
MD
136
137 /*
138 * Sanity check on lower vnode
139 */
21739618 140 lowerrootvp = nd.ni_vp;
984263bc 141
21739618
MD
142 vrele(nd.ni_dvp);
143 nd.ni_dvp = NULLVP;
984263bc
MD
144
145 /*
146 * Check multi null mount to avoid `lock against myself' panic.
147 */
148 if (lowerrootvp == VTONULL(mp->mnt_vnodecovered)->null_lowervp) {
149 NULLFSDEBUG("nullfs_mount: multi null mount?\n");
150 vput(lowerrootvp);
151 return (EDEADLK);
152 }
153
154 xmp = (struct null_mount *) malloc(sizeof(struct null_mount),
155 M_NULLFSMNT, M_WAITOK); /* XXX */
156
157 /*
158 * Save reference to underlying FS
159 */
160 xmp->nullm_vfs = lowerrootvp->v_mount;
161
0961aa92
MD
162 vfs_add_vnodeops(&mp->mnt_vn_ops, null_vnodeop_entries);
163
984263bc
MD
164 /*
165 * Save reference. Each mount also holds
166 * a reference on the root vnode.
167 */
168 error = null_node_create(mp, lowerrootvp, &vp);
169 /*
170 * Unlock the node (either the lower or the alias)
171 */
5fd012e0 172 VOP_UNLOCK(vp, 0, td);
984263bc
MD
173 /*
174 * Make sure the node alias worked
175 */
176 if (error) {
177 vrele(lowerrootvp);
178 free(xmp, M_NULLFSMNT); /* XXX */
179 return (error);
180 }
181
182 /*
183 * Keep a held reference to the root vnode.
184 * It is vrele'd in nullfs_unmount.
185 */
186 nullm_rootvp = vp;
187 nullm_rootvp->v_flag |= VROOT;
188 xmp->nullm_rootvp = nullm_rootvp;
189 if (NULLVPTOLOWERVP(nullm_rootvp)->v_mount->mnt_flag & MNT_LOCAL)
190 mp->mnt_flag |= MNT_LOCAL;
191 mp->mnt_data = (qaddr_t) xmp;
192 vfs_getnewfsid(mp);
193
194 (void) copyinstr(path, mp->mnt_stat.f_mntonname, MNAMELEN - 1, &size);
195 bzero(mp->mnt_stat.f_mntonname + size, MNAMELEN - size);
196 (void) copyinstr(args.target, mp->mnt_stat.f_mntfromname, MNAMELEN - 1,
197 &size);
198 bzero(mp->mnt_stat.f_mntfromname + size, MNAMELEN - size);
dadab5e9 199 (void)nullfs_statfs(mp, &mp->mnt_stat, td);
984263bc
MD
200 NULLFSDEBUG("nullfs_mount: lower %s, alias at %s\n",
201 mp->mnt_stat.f_mntfromname, mp->mnt_stat.f_mntonname);
202 return (0);
203}
204
205/*
206 * VFS start. Nothing needed here - the start routine
207 * on the underlying filesystem will have been called
208 * when that filesystem was mounted.
209 */
210static int
dadab5e9 211nullfs_start(struct mount *mp, int flags, struct thread *td)
984263bc
MD
212{
213 return (0);
dadab5e9 214 /* return VFS_START(MOUNTTONULLMOUNT(mp)->nullm_vfs, flags, td); */
984263bc
MD
215}
216
217/*
218 * Free reference to null layer
219 */
220static int
dadab5e9 221nullfs_unmount(struct mount *mp, int mntflags, struct thread *td)
984263bc
MD
222{
223 void *mntdata;
224 int error;
225 int flags = 0;
226
227 NULLFSDEBUG("nullfs_unmount: mp = %p\n", (void *)mp);
228
229 if (mntflags & MNT_FORCE)
230 flags |= FORCECLOSE;
231
232 /* There is 1 extra root vnode reference (nullm_rootvp). */
233 error = vflush(mp, 1, flags);
234 if (error)
235 return (error);
236
237 /*
238 * Finally, throw away the null_mount structure
239 */
240 mntdata = mp->mnt_data;
241 mp->mnt_data = 0;
242 free(mntdata, M_NULLFSMNT);
243 return 0;
244}
245
246static int
dadab5e9 247nullfs_root(struct mount *mp, struct vnode **vpp)
984263bc 248{
dadab5e9 249 struct thread *td = curthread; /* XXX */
984263bc
MD
250 struct vnode *vp;
251
252 NULLFSDEBUG("nullfs_root(mp = %p, vp = %p->%p)\n", (void *)mp,
253 (void *)MOUNTTONULLMOUNT(mp)->nullm_rootvp,
254 (void *)NULLVPTOLOWERVP(MOUNTTONULLMOUNT(mp)->nullm_rootvp));
255
256 /*
257 * Return locked reference to root.
258 */
259 vp = MOUNTTONULLMOUNT(mp)->nullm_rootvp;
597aea93 260 vref(vp);
984263bc
MD
261
262#ifdef NULLFS_DEBUG
263 if (VOP_ISLOCKED(vp, NULL)) {
264 Debugger("root vnode is locked.\n");
265 vrele(vp);
266 return (EDEADLK);
267 }
268#endif
5fd012e0 269 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, td);
984263bc
MD
270 *vpp = vp;
271 return 0;
272}
273
274static int
f4a3189a
CP
275nullfs_quotactl(struct mount *mp, int cmd, uid_t uid, caddr_t arg,
276 struct thread *td)
984263bc 277{
dadab5e9 278 return VFS_QUOTACTL(MOUNTTONULLMOUNT(mp)->nullm_vfs, cmd, uid, arg, td);
984263bc
MD
279}
280
281static int
dadab5e9 282nullfs_statfs(struct mount *mp, struct statfs *sbp, struct thread *td)
984263bc
MD
283{
284 int error;
285 struct statfs mstat;
286
287 NULLFSDEBUG("nullfs_statfs(mp = %p, vp = %p->%p)\n", (void *)mp,
288 (void *)MOUNTTONULLMOUNT(mp)->nullm_rootvp,
289 (void *)NULLVPTOLOWERVP(MOUNTTONULLMOUNT(mp)->nullm_rootvp));
290
291 bzero(&mstat, sizeof(mstat));
292
dadab5e9 293 error = VFS_STATFS(MOUNTTONULLMOUNT(mp)->nullm_vfs, &mstat, td);
984263bc
MD
294 if (error)
295 return (error);
296
297 /* now copy across the "interesting" information and fake the rest */
298 sbp->f_type = mstat.f_type;
299 sbp->f_flags = mstat.f_flags;
300 sbp->f_bsize = mstat.f_bsize;
301 sbp->f_iosize = mstat.f_iosize;
302 sbp->f_blocks = mstat.f_blocks;
303 sbp->f_bfree = mstat.f_bfree;
304 sbp->f_bavail = mstat.f_bavail;
305 sbp->f_files = mstat.f_files;
306 sbp->f_ffree = mstat.f_ffree;
307 if (sbp != &mp->mnt_stat) {
308 bcopy(&mp->mnt_stat.f_fsid, &sbp->f_fsid, sizeof(sbp->f_fsid));
309 bcopy(mp->mnt_stat.f_mntonname, sbp->f_mntonname, MNAMELEN);
310 bcopy(mp->mnt_stat.f_mntfromname, sbp->f_mntfromname, MNAMELEN);
311 }
312 return (0);
313}
314
315static int
f4a3189a 316nullfs_sync(struct mount *mp, int waitfor, struct thread *td)
984263bc
MD
317{
318 /*
319 * XXX - Assumes no data cached at null layer.
320 */
321 return (0);
322}
323
324static int
f4a3189a 325nullfs_vget(struct mount *mp, ino_t ino, struct vnode **vpp)
984263bc
MD
326{
327
328 return VFS_VGET(MOUNTTONULLMOUNT(mp)->nullm_vfs, ino, vpp);
329}
330
331static int
f4a3189a 332nullfs_fhtovp(struct mount *mp, struct fid *fidp, struct vnode **vpp)
984263bc
MD
333{
334
335 return VFS_FHTOVP(MOUNTTONULLMOUNT(mp)->nullm_vfs, fidp, vpp);
336}
337
338static int
f4a3189a
CP
339nullfs_checkexp(struct mount *mp, struct sockaddr *nam, int *extflagsp,
340 struct ucred **credanonp)
984263bc
MD
341{
342
343 return VFS_CHECKEXP(MOUNTTONULLMOUNT(mp)->nullm_vfs, nam,
344 extflagsp, credanonp);
345}
346
347static int
f4a3189a 348nullfs_vptofh(struct vnode *vp, struct fid *fhp)
984263bc
MD
349{
350 return VFS_VPTOFH(NULLVPTOLOWERVP(vp), fhp);
351}
352
353static int
f4a3189a
CP
354nullfs_extattrctl(struct mount *mp, int cmd, const char *attrname, caddr_t arg,
355 struct thread *td)
984263bc
MD
356{
357 return VFS_EXTATTRCTL(MOUNTTONULLMOUNT(mp)->nullm_vfs, cmd, attrname,
dadab5e9 358 arg, td);
984263bc
MD
359}
360
361
362static struct vfsops null_vfsops = {
363 nullfs_mount,
364 nullfs_start,
365 nullfs_unmount,
366 nullfs_root,
367 nullfs_quotactl,
368 nullfs_statfs,
369 nullfs_sync,
370 nullfs_vget,
371 nullfs_fhtovp,
372 nullfs_checkexp,
373 nullfs_vptofh,
374 nullfs_init,
375 nullfs_uninit,
376 nullfs_extattrctl,
377};
378
379VFS_SET(null_vfsops, null, VFCF_LOOPBACK);