Allow null mounts to accept -o update
[dragonfly.git] / sys / vfs / nullfs / null_vfsops.c
CommitLineData
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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 $
67863d04 40 * $DragonFly: src/sys/vfs/nullfs/null_vfsops.c,v 1.31 2008/09/17 21:44:25 dillon Exp $
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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>
fad57d0e 55#include <sys/nlookup.h>
67863d04 56#include <sys/mountctl.h>
1f2de5d4 57#include "null.h"
984263bc 58
66a1ddf5 59extern struct vop_ops null_vnode_vops;
0961aa92 60
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61static MALLOC_DEFINE(M_NULLFSMNT, "NULLFS mount", "NULLFS mount structure");
62
984263bc 63static int nullfs_root(struct mount *mp, struct vnode **vpp);
984263bc 64static int nullfs_statfs(struct mount *mp, struct statfs *sbp,
acde96db 65 struct ucred *cred);
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66
67/*
68 * Mount null layer
69 */
70static int
acde96db 71nullfs_mount(struct mount *mp, char *path, caddr_t data, struct ucred *cred)
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72{
73 int error = 0;
74 struct null_args args;
8cb8b61a 75 struct vnode *rootvp;
984263bc 76 struct null_mount *xmp;
973c11b9 77 size_t size;
fad57d0e 78 struct nlookupdata nd;
67863d04 79 fhandle_t fh;
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80
81 NULLFSDEBUG("nullfs_mount(mp = %p)\n", (void *)mp);
82
83 /*
8b02b69a 84 * Get argument
984263bc 85 */
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86 error = copyin(data, (caddr_t)&args, sizeof(struct null_args));
87 if (error)
88 return (error);
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89
90 /*
8b02b69a
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91 * XXX: Should we process mount export info ?
92 * If not, returning zero here is enough as the actual ro/rw update is
93 * being done in sys_mount().
984263bc 94 */
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95 if (mp->mnt_flag & MNT_UPDATE) {
96 xmp = MOUNTTONULLMOUNT(mp);
97 error = vfs_export(mp, &xmp->export, &args.export);
984263bc 98 return (error);
8b02b69a 99 }
984263bc 100
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101 /*
102 * Find lower node
103 */
8cb8b61a 104 rootvp = NULL;
fad57d0e 105 error = nlookup_init(&nd, args.target, UIO_USERSPACE, NLC_FOLLOW);
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106 if (error)
107 goto fail1;
108 error = nlookup(&nd);
109 if (error)
110 goto fail2;
111 error = cache_vget(&nd.nl_nch, nd.nl_cred, LK_EXCLUSIVE, &rootvp);
112 if (error)
113 goto fail2;
984263bc 114
77652cad 115 xmp = (struct null_mount *) kmalloc(sizeof(struct null_mount),
67863d04 116 M_NULLFSMNT, M_WAITOK | M_ZERO);
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117
118 /*
119 * Save reference to underlying FS
28623bf9 120 *
8cb8b61a 121 * As lite stacking enters the scene, the old way of doing this
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122 * -- via the vnode -- is not good enough anymore. Use the
123 * underlying filesystem's namecache handle as our mount point
124 * root, adjusting the mount to point to us.
125 *
126 * NCF_ISMOUNTPT is normally set on the mount point, but we also
127 * want to set it on the base directory being mounted to prevent
128 * that directory from being destroyed out from under the nullfs
129 * mount.
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130 *
131 * The forwarding mount pointer (xmp->nullm_vfs) must be set to
132 * the actual target filesystem. If the target filesystem was
133 * resolved via a nullfs mount nd.nl_nch.mount will be pointing
134 * to the nullfs mount structure instead of the target filesystem,
135 * which would otherwise cause the mount VOPS and VFSOPS to recurse
136 * endlessly. If we are mounting via a nullfs mount we inherit
137 * its read-only state, if set.
8cb8b61a 138 */
28623bf9 139 xmp->nullm_vfs = nd.nl_nch.mount;
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140 if (xmp->nullm_vfs != rootvp->v_mount) {
141 if (xmp->nullm_vfs->mnt_flag & MNT_RDONLY)
142 mp->mnt_flag |= MNT_RDONLY;
143 xmp->nullm_vfs = rootvp->v_mount;
144 }
145
146 /*
147 * ncmountpt is the parent glue. When mounting a nullfs via a nullfs
148 * we retain the parent nullfs to create a unique chain tuple.
149 */
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150 mp->mnt_ncmountpt = nd.nl_nch;
151 cache_changemount(&mp->mnt_ncmountpt, mp);
152 mp->mnt_ncmountpt.ncp->nc_flag |= NCF_ISMOUNTPT;
153 cache_unlock(&mp->mnt_ncmountpt);
154 cache_zero(&nd.nl_nch);
8cb8b61a 155 nlookup_done(&nd);
984263bc 156
66a1ddf5 157 vfs_add_vnodeops(mp, &null_vnode_vops, &mp->mnt_vn_norm_ops);
0961aa92 158
28623bf9 159 vn_unlock(rootvp); /* leave reference intact */
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160
161 /*
162 * Keep a held reference to the root vnode.
163 * It is vrele'd in nullfs_unmount.
164 */
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165 xmp->nullm_rootvp = rootvp;
166 /*
167 * XXX What's the proper safety condition for querying
168 * the underlying mount? Is this flag tuning necessary
169 * at all?
170 */
171 if (xmp->nullm_vfs->mnt_flag & MNT_LOCAL)
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172 mp->mnt_flag |= MNT_LOCAL;
173 mp->mnt_data = (qaddr_t) xmp;
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174
175 /*
176 * Try to create a unique but non-random fsid for the nullfs to
177 * allow it to be exported via NFS.
178 */
179 bzero(&fh, sizeof(fh));
180 fh.fh_fsid = rootvp->v_mount->mnt_stat.f_fsid;
181 if (VFS_VPTOFH(rootvp, &fh.fh_fid) == 0) {
182 fh.fh_fsid.val[1] ^= crc32(&fh.fh_fid, sizeof(fh.fh_fid));
183 vfs_setfsid(mp, &fh.fh_fsid);
184 } else {
185 vfs_getnewfsid(mp);
186 }
984263bc 187
984263bc 188 (void) copyinstr(args.target, mp->mnt_stat.f_mntfromname, MNAMELEN - 1,
973c11b9 189 &size);
984263bc 190 bzero(mp->mnt_stat.f_mntfromname + size, MNAMELEN - size);
acde96db 191 (void)nullfs_statfs(mp, &mp->mnt_stat, cred);
984263bc 192 NULLFSDEBUG("nullfs_mount: lower %s, alias at %s\n",
75ffff0d 193 mp->mnt_stat.f_mntfromname, mp->mnt_stat.f_mntfromname);
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194
195 /*
196 * So unmount won't complain about namecache refs still existing
197 */
198 mp->mnt_kern_flag |= MNTK_NCALIASED;
984263bc 199 return (0);
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200fail2:
201 nlookup_done(&nd);
202fail1:
203 return (error);
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204}
205
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206/*
207 * Free reference to null layer
208 */
209static int
acde96db 210nullfs_unmount(struct mount *mp, int mntflags)
984263bc 211{
b81dacf0 212 struct null_mount *xmp;
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213 int flags = 0;
214
215 NULLFSDEBUG("nullfs_unmount: mp = %p\n", (void *)mp);
216
217 if (mntflags & MNT_FORCE)
218 flags |= FORCECLOSE;
219
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220 /*
221 * Finally, throw away the null_mount structure
222 */
8e77d370 223 xmp = (void *)mp->mnt_data;
984263bc 224 mp->mnt_data = 0;
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225 if (xmp->nullm_rootvp) {
226 vrele(xmp->nullm_rootvp);
227 xmp->nullm_rootvp = NULL;
228 }
229 kfree(xmp, M_NULLFSMNT);
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230 return 0;
231}
232
233static int
dadab5e9 234nullfs_root(struct mount *mp, struct vnode **vpp)
984263bc 235{
984263bc 236 struct vnode *vp;
44b1cf3d 237 int error;
984263bc 238
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239 NULLFSDEBUG("nullfs_root(mp = %p, vp = %p)\n", (void *)mp,
240 (void *)MOUNTTONULLMOUNT(mp)->nullm_rootvp);
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241
242 /*
243 * Return locked reference to root.
244 */
245 vp = MOUNTTONULLMOUNT(mp)->nullm_rootvp;
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246 error = vget(vp, LK_EXCLUSIVE | LK_RETRY);
247 if (error == 0)
248 *vpp = vp;
249 return (error);
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250}
251
252static int
f4a3189a 253nullfs_quotactl(struct mount *mp, int cmd, uid_t uid, caddr_t arg,
acde96db 254 struct ucred *cred)
984263bc 255{
acde96db 256 return VFS_QUOTACTL(MOUNTTONULLMOUNT(mp)->nullm_vfs, cmd, uid, arg, cred);
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257}
258
259static int
acde96db 260nullfs_statfs(struct mount *mp, struct statfs *sbp, struct ucred *cred)
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261{
262 int error;
263 struct statfs mstat;
264
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265 NULLFSDEBUG("nullfs_statfs(mp = %p, vp = %p)\n", (void *)mp,
266 (void *)MOUNTTONULLMOUNT(mp)->nullm_rootvp);
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267
268 bzero(&mstat, sizeof(mstat));
269
acde96db 270 error = VFS_STATFS(MOUNTTONULLMOUNT(mp)->nullm_vfs, &mstat, cred);
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271 if (error)
272 return (error);
273
274 /* now copy across the "interesting" information and fake the rest */
275 sbp->f_type = mstat.f_type;
276 sbp->f_flags = mstat.f_flags;
277 sbp->f_bsize = mstat.f_bsize;
278 sbp->f_iosize = mstat.f_iosize;
279 sbp->f_blocks = mstat.f_blocks;
280 sbp->f_bfree = mstat.f_bfree;
281 sbp->f_bavail = mstat.f_bavail;
282 sbp->f_files = mstat.f_files;
283 sbp->f_ffree = mstat.f_ffree;
284 if (sbp != &mp->mnt_stat) {
285 bcopy(&mp->mnt_stat.f_fsid, &sbp->f_fsid, sizeof(sbp->f_fsid));
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286 bcopy(mp->mnt_stat.f_mntfromname, sbp->f_mntfromname, MNAMELEN);
287 }
288 return (0);
289}
290
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291/*
292 * Implement NFS export tracking
293 */
984263bc 294static int
f4a3189a
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295nullfs_checkexp(struct mount *mp, struct sockaddr *nam, int *extflagsp,
296 struct ucred **credanonp)
984263bc 297{
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298 struct null_mount *xmp = (void *)mp->mnt_data;
299 struct netcred *np;
300 int error;
984263bc 301
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302 np = vfs_export_lookup(mp, &xmp->export, nam);
303 if (np) {
304 *extflagsp = np->netc_exflags;
305 *credanonp = &np->netc_anon;
306 error = 0;
307 } else {
308 error = EACCES;
309 }
310 return(error);
311#if 0
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312 return VFS_CHECKEXP(MOUNTTONULLMOUNT(mp)->nullm_vfs, nam,
313 extflagsp, credanonp);
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314#endif
315}
316
317int
318nullfs_export(struct mount *mp, int op, const struct export_args *export)
319{
320 struct null_mount *xmp = (void *)mp->mnt_data;
321 int error;
322
323 switch(op) {
324 case MOUNTCTL_SET_EXPORT:
325 error = vfs_export(mp, &xmp->export, export);
326 break;
327 default:
328 error = EOPNOTSUPP;
329 break;
330 }
331 return(error);
332}
333
334/*
335 * Pass through file handle conversion functions.
336 */
337static int
338nullfs_vptofh(struct vnode *vp, struct fid *fhp)
339{
340 return VFS_VPTOFH(vp, fhp);
341}
342
343/*
344 * Pass through file handle conversion functions.
345 *
346 * NOTE: currently only HAMMER uses rootvp. HAMMER uses rootvp only
347 * to enforce PFS isolation.
348 */
349static int
350nullfs_fhtovp(struct mount *mp, struct vnode *rootvp,
351 struct fid *fhp, struct vnode **vpp)
352{
353 struct null_mount *xmp = MOUNTTONULLMOUNT(mp);
354
355 return VFS_FHTOVP(xmp->nullm_vfs, xmp->nullm_rootvp, fhp, vpp);
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356}
357
984263bc 358static int
f4a3189a 359nullfs_extattrctl(struct mount *mp, int cmd, const char *attrname, caddr_t arg,
acde96db 360 struct ucred *cred)
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361{
362 return VFS_EXTATTRCTL(MOUNTTONULLMOUNT(mp)->nullm_vfs, cmd, attrname,
acde96db 363 arg, cred);
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364}
365
366
367static struct vfsops null_vfsops = {
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368 .vfs_mount = nullfs_mount,
369 .vfs_unmount = nullfs_unmount,
370 .vfs_root = nullfs_root,
371 .vfs_quotactl = nullfs_quotactl,
372 .vfs_statfs = nullfs_statfs,
373 .vfs_sync = vfs_stdsync,
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374 .vfs_extattrctl = nullfs_extattrctl,
375 .vfs_fhtovp = nullfs_fhtovp,
376 .vfs_vptofh = nullfs_vptofh,
377 .vfs_checkexp = nullfs_checkexp
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378};
379
380VFS_SET(null_vfsops, null, VFCF_LOOPBACK);