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[dragonfly.git] / sys / vfs / nullfs / null_vfsops.c
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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 $
66a1ddf5 40 * $DragonFly: src/sys/vfs/nullfs/null_vfsops.c,v 1.22 2006/07/18 22:22:15 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>
1f2de5d4 56#include "null.h"
984263bc 57
66a1ddf5 58extern struct vop_ops null_vnode_vops;
0961aa92 59
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60static MALLOC_DEFINE(M_NULLFSMNT, "NULLFS mount", "NULLFS mount structure");
61
984263bc 62static int nullfs_root(struct mount *mp, struct vnode **vpp);
984263bc 63static int nullfs_statfs(struct mount *mp, struct statfs *sbp,
acde96db 64 struct ucred *cred);
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65
66/*
67 * Mount null layer
68 */
69static int
acde96db 70nullfs_mount(struct mount *mp, char *path, caddr_t data, struct ucred *cred)
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71{
72 int error = 0;
73 struct null_args args;
8cb8b61a 74 struct vnode *rootvp;
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75 struct null_mount *xmp;
76 u_int size;
fad57d0e 77 struct nlookupdata nd;
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78
79 NULLFSDEBUG("nullfs_mount(mp = %p)\n", (void *)mp);
80
81 /*
82 * Update is a no-op
83 */
84 if (mp->mnt_flag & MNT_UPDATE) {
85 return (EOPNOTSUPP);
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86 }
87
88 /*
89 * Get argument
90 */
91 error = copyin(data, (caddr_t)&args, sizeof(struct null_args));
92 if (error)
93 return (error);
94
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95 /*
96 * Find lower node
97 */
8cb8b61a 98 rootvp = NULL;
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99 error = nlookup_init(&nd, args.target, UIO_USERSPACE, NLC_FOLLOW);
100 if (error == 0)
101 error = nlookup(&nd);
102 if (error == 0) {
103 error = cache_vget(nd.nl_ncp, nd.nl_cred, LK_EXCLUSIVE,
8cb8b61a 104 &rootvp);
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105 }
106
107 xmp = (struct null_mount *) malloc(sizeof(struct null_mount),
108 M_NULLFSMNT, M_WAITOK); /* XXX */
109
110 /*
111 * Save reference to underlying FS
112 */
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113 /*
114 * As lite stacking enters the scene, the old way of doing this
115 * -- via the vnode -- is not good enough anymore...
116 */
117 xmp->nullm_vfs = nd.nl_ncp->nc_mount;
118 nlookup_done(&nd);
984263bc 119
66a1ddf5 120 vfs_add_vnodeops(mp, &null_vnode_vops, &mp->mnt_vn_norm_ops);
0961aa92 121
ca466bae 122 VOP_UNLOCK(rootvp, 0);
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123
124 /*
125 * Keep a held reference to the root vnode.
126 * It is vrele'd in nullfs_unmount.
127 */
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128 xmp->nullm_rootvp = rootvp;
129 /*
130 * XXX What's the proper safety condition for querying
131 * the underlying mount? Is this flag tuning necessary
132 * at all?
133 */
134 if (xmp->nullm_vfs->mnt_flag & MNT_LOCAL)
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135 mp->mnt_flag |= MNT_LOCAL;
136 mp->mnt_data = (qaddr_t) xmp;
137 vfs_getnewfsid(mp);
138
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139 (void) copyinstr(args.target, mp->mnt_stat.f_mntfromname, MNAMELEN - 1,
140 &size);
141 bzero(mp->mnt_stat.f_mntfromname + size, MNAMELEN - size);
acde96db 142 (void)nullfs_statfs(mp, &mp->mnt_stat, cred);
984263bc 143 NULLFSDEBUG("nullfs_mount: lower %s, alias at %s\n",
75ffff0d 144 mp->mnt_stat.f_mntfromname, mp->mnt_stat.f_mntfromname);
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145 return (0);
146}
147
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148/*
149 * Free reference to null layer
150 */
151static int
acde96db 152nullfs_unmount(struct mount *mp, int mntflags)
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153{
154 void *mntdata;
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155 int flags = 0;
156
157 NULLFSDEBUG("nullfs_unmount: mp = %p\n", (void *)mp);
158
159 if (mntflags & MNT_FORCE)
160 flags |= FORCECLOSE;
161
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162 /*
163 * Finally, throw away the null_mount structure
164 */
165 mntdata = mp->mnt_data;
166 mp->mnt_data = 0;
167 free(mntdata, M_NULLFSMNT);
168 return 0;
169}
170
171static int
dadab5e9 172nullfs_root(struct mount *mp, struct vnode **vpp)
984263bc 173{
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174 struct vnode *vp;
175
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176 NULLFSDEBUG("nullfs_root(mp = %p, vp = %p)\n", (void *)mp,
177 (void *)MOUNTTONULLMOUNT(mp)->nullm_rootvp);
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178
179 /*
180 * Return locked reference to root.
181 */
182 vp = MOUNTTONULLMOUNT(mp)->nullm_rootvp;
597aea93 183 vref(vp);
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184
185#ifdef NULLFS_DEBUG
186 if (VOP_ISLOCKED(vp, NULL)) {
187 Debugger("root vnode is locked.\n");
188 vrele(vp);
189 return (EDEADLK);
190 }
191#endif
ca466bae 192 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
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193 *vpp = vp;
194 return 0;
195}
196
197static int
f4a3189a 198nullfs_quotactl(struct mount *mp, int cmd, uid_t uid, caddr_t arg,
acde96db 199 struct ucred *cred)
984263bc 200{
acde96db 201 return VFS_QUOTACTL(MOUNTTONULLMOUNT(mp)->nullm_vfs, cmd, uid, arg, cred);
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202}
203
204static int
acde96db 205nullfs_statfs(struct mount *mp, struct statfs *sbp, struct ucred *cred)
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206{
207 int error;
208 struct statfs mstat;
209
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210 NULLFSDEBUG("nullfs_statfs(mp = %p, vp = %p)\n", (void *)mp,
211 (void *)MOUNTTONULLMOUNT(mp)->nullm_rootvp);
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212
213 bzero(&mstat, sizeof(mstat));
214
acde96db 215 error = VFS_STATFS(MOUNTTONULLMOUNT(mp)->nullm_vfs, &mstat, cred);
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216 if (error)
217 return (error);
218
219 /* now copy across the "interesting" information and fake the rest */
220 sbp->f_type = mstat.f_type;
221 sbp->f_flags = mstat.f_flags;
222 sbp->f_bsize = mstat.f_bsize;
223 sbp->f_iosize = mstat.f_iosize;
224 sbp->f_blocks = mstat.f_blocks;
225 sbp->f_bfree = mstat.f_bfree;
226 sbp->f_bavail = mstat.f_bavail;
227 sbp->f_files = mstat.f_files;
228 sbp->f_ffree = mstat.f_ffree;
229 if (sbp != &mp->mnt_stat) {
230 bcopy(&mp->mnt_stat.f_fsid, &sbp->f_fsid, sizeof(sbp->f_fsid));
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231 bcopy(mp->mnt_stat.f_mntfromname, sbp->f_mntfromname, MNAMELEN);
232 }
233 return (0);
234}
235
984263bc 236static int
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237nullfs_checkexp(struct mount *mp, struct sockaddr *nam, int *extflagsp,
238 struct ucred **credanonp)
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239{
240
241 return VFS_CHECKEXP(MOUNTTONULLMOUNT(mp)->nullm_vfs, nam,
242 extflagsp, credanonp);
243}
244
984263bc 245static int
f4a3189a 246nullfs_extattrctl(struct mount *mp, int cmd, const char *attrname, caddr_t arg,
acde96db 247 struct ucred *cred)
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248{
249 return VFS_EXTATTRCTL(MOUNTTONULLMOUNT(mp)->nullm_vfs, cmd, attrname,
acde96db 250 arg, cred);
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251}
252
253
254static struct vfsops null_vfsops = {
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255 .vfs_mount = nullfs_mount,
256 .vfs_unmount = nullfs_unmount,
257 .vfs_root = nullfs_root,
258 .vfs_quotactl = nullfs_quotactl,
259 .vfs_statfs = nullfs_statfs,
260 .vfs_sync = vfs_stdsync,
43c45e8f 261 .vfs_checkexp = nullfs_checkexp,
43c45e8f 262 .vfs_extattrctl = nullfs_extattrctl
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263};
264
265VFS_SET(null_vfsops, null, VFCF_LOOPBACK);