Fix .Os and a .Xr. Expand HISTORY a bit.
[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 $
ca466bae 40 * $DragonFly: src/sys/vfs/nullfs/null_vfsops.c,v 1.20 2006/05/05 21:15:10 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
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58extern struct vnodeopv_entry_desc null_vnodeop_entries[];
59
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60static MALLOC_DEFINE(M_NULLFSMNT, "NULLFS mount", "NULLFS mount structure");
61
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62static int nullfs_checkexp(struct mount *mp, struct sockaddr *nam,
63 int *extflagsp, struct ucred **credanonp);
64static int nullfs_mount(struct mount *mp, char *path, caddr_t data,
21739618 65 struct thread *td);
984263bc 66static int nullfs_quotactl(struct mount *mp, int cmd, uid_t uid,
dadab5e9 67 caddr_t arg, struct thread *td);
984263bc 68static int nullfs_root(struct mount *mp, struct vnode **vpp);
984263bc 69static int nullfs_statfs(struct mount *mp, struct statfs *sbp,
dadab5e9 70 struct thread *td);
dadab5e9 71static int nullfs_unmount(struct mount *mp, int mntflags, struct thread *td);
984263bc 72static int nullfs_extattrctl(struct mount *mp, int cmd,
dadab5e9 73 const char *attrname, caddr_t arg, struct thread *td);
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74
75/*
76 * Mount null layer
77 */
78static int
21739618 79nullfs_mount(struct mount *mp, char *path, caddr_t data, struct thread *td)
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80{
81 int error = 0;
82 struct null_args args;
8cb8b61a 83 struct vnode *rootvp;
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84 struct null_mount *xmp;
85 u_int size;
fad57d0e 86 struct nlookupdata nd;
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87
88 NULLFSDEBUG("nullfs_mount(mp = %p)\n", (void *)mp);
89
90 /*
91 * Update is a no-op
92 */
93 if (mp->mnt_flag & MNT_UPDATE) {
94 return (EOPNOTSUPP);
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95 }
96
97 /*
98 * Get argument
99 */
100 error = copyin(data, (caddr_t)&args, sizeof(struct null_args));
101 if (error)
102 return (error);
103
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104 /*
105 * Find lower node
106 */
8cb8b61a 107 rootvp = NULL;
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108 error = nlookup_init(&nd, args.target, UIO_USERSPACE, NLC_FOLLOW);
109 if (error == 0)
110 error = nlookup(&nd);
111 if (error == 0) {
112 error = cache_vget(nd.nl_ncp, nd.nl_cred, LK_EXCLUSIVE,
8cb8b61a 113 &rootvp);
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114 }
115
116 xmp = (struct null_mount *) malloc(sizeof(struct null_mount),
117 M_NULLFSMNT, M_WAITOK); /* XXX */
118
119 /*
120 * Save reference to underlying FS
121 */
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122 /*
123 * As lite stacking enters the scene, the old way of doing this
124 * -- via the vnode -- is not good enough anymore...
125 */
126 xmp->nullm_vfs = nd.nl_ncp->nc_mount;
127 nlookup_done(&nd);
984263bc 128
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129 vfs_add_vnodeops(mp, &mp->mnt_vn_norm_ops,
130 null_vnodeop_entries, 0);
0961aa92 131
ca466bae 132 VOP_UNLOCK(rootvp, 0);
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133
134 /*
135 * Keep a held reference to the root vnode.
136 * It is vrele'd in nullfs_unmount.
137 */
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138 xmp->nullm_rootvp = rootvp;
139 /*
140 * XXX What's the proper safety condition for querying
141 * the underlying mount? Is this flag tuning necessary
142 * at all?
143 */
144 if (xmp->nullm_vfs->mnt_flag & MNT_LOCAL)
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145 mp->mnt_flag |= MNT_LOCAL;
146 mp->mnt_data = (qaddr_t) xmp;
147 vfs_getnewfsid(mp);
148
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149 (void) copyinstr(args.target, mp->mnt_stat.f_mntfromname, MNAMELEN - 1,
150 &size);
151 bzero(mp->mnt_stat.f_mntfromname + size, MNAMELEN - size);
dadab5e9 152 (void)nullfs_statfs(mp, &mp->mnt_stat, td);
984263bc 153 NULLFSDEBUG("nullfs_mount: lower %s, alias at %s\n",
75ffff0d 154 mp->mnt_stat.f_mntfromname, mp->mnt_stat.f_mntfromname);
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155 return (0);
156}
157
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158/*
159 * Free reference to null layer
160 */
161static int
dadab5e9 162nullfs_unmount(struct mount *mp, int mntflags, struct thread *td)
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163{
164 void *mntdata;
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165 int flags = 0;
166
167 NULLFSDEBUG("nullfs_unmount: mp = %p\n", (void *)mp);
168
169 if (mntflags & MNT_FORCE)
170 flags |= FORCECLOSE;
171
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172 /*
173 * Finally, throw away the null_mount structure
174 */
175 mntdata = mp->mnt_data;
176 mp->mnt_data = 0;
177 free(mntdata, M_NULLFSMNT);
178 return 0;
179}
180
181static int
dadab5e9 182nullfs_root(struct mount *mp, struct vnode **vpp)
984263bc 183{
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184 struct vnode *vp;
185
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186 NULLFSDEBUG("nullfs_root(mp = %p, vp = %p)\n", (void *)mp,
187 (void *)MOUNTTONULLMOUNT(mp)->nullm_rootvp);
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188
189 /*
190 * Return locked reference to root.
191 */
192 vp = MOUNTTONULLMOUNT(mp)->nullm_rootvp;
597aea93 193 vref(vp);
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194
195#ifdef NULLFS_DEBUG
196 if (VOP_ISLOCKED(vp, NULL)) {
197 Debugger("root vnode is locked.\n");
198 vrele(vp);
199 return (EDEADLK);
200 }
201#endif
ca466bae 202 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
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203 *vpp = vp;
204 return 0;
205}
206
207static int
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208nullfs_quotactl(struct mount *mp, int cmd, uid_t uid, caddr_t arg,
209 struct thread *td)
984263bc 210{
dadab5e9 211 return VFS_QUOTACTL(MOUNTTONULLMOUNT(mp)->nullm_vfs, cmd, uid, arg, td);
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212}
213
214static int
dadab5e9 215nullfs_statfs(struct mount *mp, struct statfs *sbp, struct thread *td)
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216{
217 int error;
218 struct statfs mstat;
219
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220 NULLFSDEBUG("nullfs_statfs(mp = %p, vp = %p)\n", (void *)mp,
221 (void *)MOUNTTONULLMOUNT(mp)->nullm_rootvp);
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222
223 bzero(&mstat, sizeof(mstat));
224
dadab5e9 225 error = VFS_STATFS(MOUNTTONULLMOUNT(mp)->nullm_vfs, &mstat, td);
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226 if (error)
227 return (error);
228
229 /* now copy across the "interesting" information and fake the rest */
230 sbp->f_type = mstat.f_type;
231 sbp->f_flags = mstat.f_flags;
232 sbp->f_bsize = mstat.f_bsize;
233 sbp->f_iosize = mstat.f_iosize;
234 sbp->f_blocks = mstat.f_blocks;
235 sbp->f_bfree = mstat.f_bfree;
236 sbp->f_bavail = mstat.f_bavail;
237 sbp->f_files = mstat.f_files;
238 sbp->f_ffree = mstat.f_ffree;
239 if (sbp != &mp->mnt_stat) {
240 bcopy(&mp->mnt_stat.f_fsid, &sbp->f_fsid, sizeof(sbp->f_fsid));
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241 bcopy(mp->mnt_stat.f_mntfromname, sbp->f_mntfromname, MNAMELEN);
242 }
243 return (0);
244}
245
984263bc 246static int
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247nullfs_checkexp(struct mount *mp, struct sockaddr *nam, int *extflagsp,
248 struct ucred **credanonp)
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249{
250
251 return VFS_CHECKEXP(MOUNTTONULLMOUNT(mp)->nullm_vfs, nam,
252 extflagsp, credanonp);
253}
254
984263bc 255static int
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256nullfs_extattrctl(struct mount *mp, int cmd, const char *attrname, caddr_t arg,
257 struct thread *td)
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258{
259 return VFS_EXTATTRCTL(MOUNTTONULLMOUNT(mp)->nullm_vfs, cmd, attrname,
dadab5e9 260 arg, td);
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261}
262
263
264static struct vfsops null_vfsops = {
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265 .vfs_mount = nullfs_mount,
266 .vfs_unmount = nullfs_unmount,
267 .vfs_root = nullfs_root,
268 .vfs_quotactl = nullfs_quotactl,
269 .vfs_statfs = nullfs_statfs,
270 .vfs_sync = vfs_stdsync,
43c45e8f 271 .vfs_checkexp = nullfs_checkexp,
43c45e8f 272 .vfs_extattrctl = nullfs_extattrctl
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273};
274
275VFS_SET(null_vfsops, null, VFCF_LOOPBACK);