Rename printf -> kprintf in sys/ and add some defines where necessary
[dragonfly.git] / sys / vfs / union / union_vfsops.c
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1/*
2 * Copyright (c) 1994, 1995 The Regents of the University of California.
3 * Copyright (c) 1994, 1995 Jan-Simon Pendry.
4 * All rights reserved.
5 *
6 * This code is derived from software donated to Berkeley by
7 * Jan-Simon Pendry.
8 *
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
11 * are met:
12 * 1. Redistributions of source code must retain the above copyright
13 * notice, this list of conditions and the following disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 * notice, this list of conditions and the following disclaimer in the
16 * documentation and/or other materials provided with the distribution.
17 * 3. All advertising materials mentioning features or use of this software
18 * must display the following acknowledgement:
19 * This product includes software developed by the University of
20 * California, Berkeley and its contributors.
21 * 4. Neither the name of the University nor the names of its contributors
22 * may be used to endorse or promote products derived from this software
23 * without specific prior written permission.
24 *
25 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
26 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
27 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
28 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
29 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
30 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
31 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
32 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
33 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
34 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
35 * SUCH DAMAGE.
36 *
37 * @(#)union_vfsops.c 8.20 (Berkeley) 5/20/95
38 * $FreeBSD: src/sys/miscfs/union/union_vfsops.c,v 1.39.2.2 2001/10/25 19:18:53 dillon Exp $
086c1d7e 39 * $DragonFly: src/sys/vfs/union/union_vfsops.c,v 1.29 2006/12/23 00:41:30 swildner Exp $
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40 */
41
42/*
43 * Union Layer
44 */
45
46#include <sys/param.h>
47#include <sys/systm.h>
48#include <sys/kernel.h>
49#include <sys/proc.h>
50#include <sys/vnode.h>
51#include <sys/mount.h>
fad57d0e 52#include <sys/nlookup.h>
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53#include <sys/namei.h>
54#include <sys/malloc.h>
55#include <sys/filedesc.h>
1f2de5d4 56#include "union.h"
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57#include <vm/vm_zone.h>
58
66a1ddf5 59extern struct vop_ops union_vnode_vops;
0961aa92 60
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61static MALLOC_DEFINE(M_UNIONFSMNT, "UNION mount", "UNION mount structure");
62
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63extern int union_init (struct vfsconf *);
64static int union_mount (struct mount *mp, char *path, caddr_t data,
acde96db 65 struct ucred *cred);
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66static int union_root (struct mount *mp, struct vnode **vpp);
67static int union_statfs (struct mount *mp, struct statfs *sbp,
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68 struct ucred *cred);
69static int union_unmount (struct mount *mp, int mntflags);
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70
71/*
72 * Mount union filesystem
73 */
74static int
acde96db 75union_mount(struct mount *mp, char *path, caddr_t data, struct ucred *cred)
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76{
77 int error = 0;
78 struct union_args args;
79 struct vnode *lowerrootvp = NULLVP;
80 struct vnode *upperrootvp = NULLVP;
81 struct union_mount *um = 0;
82 struct ucred *cred = 0;
fad57d0e 83 struct nlookupdata nd;
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84 char *cp = 0;
85 int len;
86 u_int size;
87
88 UDEBUG(("union_mount(mp = %p)\n", (void *)mp));
89
90 /*
91 * Disable clustered write, otherwise system becomes unstable.
92 */
93 mp->mnt_flag |= MNT_NOCLUSTERW;
94
95 /*
96 * Update is a no-op
97 */
98 if (mp->mnt_flag & MNT_UPDATE) {
99 /*
100 * Need to provide.
101 * 1. a way to convert between rdonly and rdwr mounts.
102 * 2. support for nfs exports.
103 */
104 error = EOPNOTSUPP;
105 goto bad;
106 }
107
108 /*
109 * Get argument
110 */
111 error = copyin(data, (caddr_t)&args, sizeof(struct union_args));
112 if (error)
113 goto bad;
114
115 /*
1d505369 116 * Obtain lower vnode.
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117 */
118
119 lowerrootvp = mp->mnt_vnodecovered;
597aea93 120 vref(lowerrootvp);
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121
122#if 0
123 /*
124 * Unlock lower node to avoid deadlock.
125 */
0961aa92 126 if (lowerrootvp->v_tag == VT_UNION)
a11aaa81 127 vn_unlock(lowerrootvp);
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128#endif
129
130 /*
fad57d0e 131 * Obtain upper vnode by calling nlookup() on the path. The
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132 * upperrootvp will be turned referenced but not locked.
133 */
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134 error = nlookup_init(&nd, args.target, UIO_USERSPACE, NLC_FOLLOW);
135 if (error == 0)
136 error = nlookup(&nd);
137 if (error == 0)
28623bf9 138 error = cache_vref(&nd.nl_nch, nd.nl_cred, &upperrootvp);
fad57d0e 139 nlookup_done(&nd);
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140 if (error)
141 goto bad;
142
984263bc 143 UDEBUG(("mount_root UPPERVP %p locked = %d\n", upperrootvp,
a11aaa81 144 vn_islocked(upperrootvp)));
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145
146 /*
147 * Check multi union mount to avoid `lock myself again' panic.
148 * Also require that it be a directory.
149 */
150 if (upperrootvp == VTOUNION(lowerrootvp)->un_uppervp) {
151#ifdef DIAGNOSTIC
086c1d7e 152 kprintf("union_mount: multi union mount?\n");
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153#endif
154 error = EDEADLK;
155 goto bad;
156 }
157
158 if (upperrootvp->v_type != VDIR) {
159 error = EINVAL;
160 goto bad;
161 }
162
163 /*
164 * Allocate our union_mount structure and populate the fields.
165 * The vnode references are stored in the union_mount as held,
166 * unlocked references. Depending on the _BELOW flag, the
167 * filesystems are viewed in a different order. In effect this
168 * is the same as providing a mount-under option to the mount
169 * syscall.
170 */
171
172 um = (struct union_mount *) malloc(sizeof(struct union_mount),
173 M_UNIONFSMNT, M_WAITOK);
174
175 bzero(um, sizeof(struct union_mount));
176
177 um->um_op = args.mntflags & UNMNT_OPMASK;
178
179 switch (um->um_op) {
180 case UNMNT_ABOVE:
181 um->um_lowervp = lowerrootvp;
182 um->um_uppervp = upperrootvp;
183 upperrootvp = NULL;
184 lowerrootvp = NULL;
185 break;
186
187 case UNMNT_BELOW:
188 um->um_lowervp = upperrootvp;
189 um->um_uppervp = lowerrootvp;
190 upperrootvp = NULL;
191 lowerrootvp = NULL;
192 break;
193
194 case UNMNT_REPLACE:
195 vrele(lowerrootvp);
196 lowerrootvp = NULL;
197 um->um_uppervp = upperrootvp;
198 um->um_lowervp = lowerrootvp;
199 upperrootvp = NULL;
200 break;
201
202 default:
203 error = EINVAL;
204 goto bad;
205 }
206
207 /*
208 * Unless the mount is readonly, ensure that the top layer
209 * supports whiteout operations
210 */
211 if ((mp->mnt_flag & MNT_RDONLY) == 0) {
fad57d0e 212 error = VOP_WHITEOUT(um->um_uppervp, NULL, NAMEI_LOOKUP);
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213 if (error)
214 goto bad;
215 }
216
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217 /*
218 * File creds and modes for shadowed files are based on the user
219 * that did the mount.
220 */
221 um->um_cred = crhold(cred);
222 um->um_cmode = UN_DIRMODE;
223 if (curproc)
224 um->um_cmode &= ~curproc->p_fd->fd_cmask;
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225
226 /*
227 * Depending on what you think the MNT_LOCAL flag might mean,
228 * you may want the && to be || on the conditional below.
229 * At the moment it has been defined that the filesystem is
230 * only local if it is all local, ie the MNT_LOCAL flag implies
231 * that the entire namespace is local. If you think the MNT_LOCAL
232 * flag implies that some of the files might be stored locally
233 * then you will want to change the conditional.
234 */
235 if (um->um_op == UNMNT_ABOVE) {
236 if (((um->um_lowervp == NULLVP) ||
237 (um->um_lowervp->v_mount->mnt_flag & MNT_LOCAL)) &&
238 (um->um_uppervp->v_mount->mnt_flag & MNT_LOCAL))
239 mp->mnt_flag |= MNT_LOCAL;
240 }
241
242 /*
243 * Copy in the upper layer's RDONLY flag. This is for the benefit
244 * of lookup() which explicitly checks the flag, rather than asking
245 * the filesystem for its own opinion. This means, that an update
246 * mount of the underlying filesystem to go from rdonly to rdwr
247 * will leave the unioned view as read-only.
248 */
249 mp->mnt_flag |= (um->um_uppervp->v_mount->mnt_flag & MNT_RDONLY);
250
251 mp->mnt_data = (qaddr_t) um;
252 vfs_getnewfsid(mp);
253
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254 switch (um->um_op) {
255 case UNMNT_ABOVE:
256 cp = "<above>:";
257 break;
258 case UNMNT_BELOW:
259 cp = "<below>:";
260 break;
261 case UNMNT_REPLACE:
262 cp = "";
263 break;
264 }
265 len = strlen(cp);
266 bcopy(cp, mp->mnt_stat.f_mntfromname, len);
267
268 cp = mp->mnt_stat.f_mntfromname + len;
269 len = MNAMELEN - len;
270
271 (void) copyinstr(args.target, cp, len - 1, &size);
272 bzero(cp + size, len - size);
273
66a1ddf5 274 vfs_add_vnodeops(mp, &union_vnode_vops, &mp->mnt_vn_norm_ops);
0961aa92 275
acde96db 276 (void)union_statfs(mp, &mp->mnt_stat, cred);
984263bc 277
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278 return (0);
279
280bad:
281 if (um) {
282 if (um->um_uppervp)
283 vrele(um->um_uppervp);
284 if (um->um_lowervp)
285 vrele(um->um_lowervp);
286 /* XXX other fields */
efda3bd0 287 kfree(um, M_UNIONFSMNT);
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288 }
289 if (cred)
290 crfree(cred);
291 if (upperrootvp)
292 vrele(upperrootvp);
293 if (lowerrootvp)
294 vrele(lowerrootvp);
295 return (error);
296}
297
298/*
299 * Free reference to union layer
300 */
301static int
acde96db 302union_unmount(struct mount *mp, int mntflags)
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303{
304 struct union_mount *um = MOUNTTOUNIONMOUNT(mp);
305 int error;
306 int freeing;
307 int flags = 0;
308
309 UDEBUG(("union_unmount(mp = %p)\n", (void *)mp));
310
311 if (mntflags & MNT_FORCE)
312 flags |= FORCECLOSE;
313
314 /*
315 * Keep flushing vnodes from the mount list.
316 * This is needed because of the un_pvp held
317 * reference to the parent vnode.
318 * If more vnodes have been freed on a given pass,
319 * the try again. The loop will iterate at most
320 * (d) times, where (d) is the maximum tree depth
321 * in the filesystem.
322 */
323 for (freeing = 0; (error = vflush(mp, 0, flags)) != 0;) {
eb945a80 324 int n = mp->mnt_nvnodelistsize;
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325
326 /* if this is unchanged then stop */
327 if (n == freeing)
328 break;
329
330 /* otherwise try once more time */
331 freeing = n;
332 }
333
334 /* If the most recent vflush failed, the filesystem is still busy. */
335 if (error)
336 return (error);
337
338 /*
339 * Discard references to upper and lower target vnodes.
340 */
341 if (um->um_lowervp)
342 vrele(um->um_lowervp);
343 vrele(um->um_uppervp);
344 crfree(um->um_cred);
345 /*
346 * Finally, throw away the union_mount structure
347 */
efda3bd0 348 kfree(mp->mnt_data, M_UNIONFSMNT); /* XXX */
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349 mp->mnt_data = 0;
350 return (0);
351}
352
353static int
262679fc 354union_root(struct mount *mp, struct vnode **vpp)
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355{
356 struct union_mount *um = MOUNTTOUNIONMOUNT(mp);
357 int error;
358
359 /*
360 * Supply an unlocked reference to um_uppervp and to um_lowervp. It
361 * is possible for um_uppervp to be locked without the associated
362 * root union_node being locked. We let union_allocvp() deal with
363 * it.
364 */
365 UDEBUG(("union_root UPPERVP %p locked = %d\n", um->um_uppervp,
a11aaa81 366 vn_islocked(um->um_uppervp)));
984263bc 367
597aea93 368 vref(um->um_uppervp);
984263bc 369 if (um->um_lowervp)
597aea93 370 vref(um->um_lowervp);
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371
372 error = union_allocvp(vpp, mp, NULLVP, NULLVP, NULL,
373 um->um_uppervp, um->um_lowervp, 1);
374 UDEBUG(("error %d\n", error));
375 UDEBUG(("union_root2 UPPERVP %p locked = %d\n", um->um_uppervp,
a11aaa81 376 vn_islocked(um->um_uppervp)));
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377
378 return (error);
379}
380
381static int
acde96db 382union_statfs(struct mount *mp, struct statfs *sbp, struct ucred *cred)
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383{
384 int error;
385 struct union_mount *um = MOUNTTOUNIONMOUNT(mp);
386 struct statfs mstat;
387 int lbsize;
388
389 UDEBUG(("union_statfs(mp = %p, lvp = %p, uvp = %p)\n",
390 (void *)mp, (void *)um->um_lowervp, (void *)um->um_uppervp));
391
392 bzero(&mstat, sizeof(mstat));
393
394 if (um->um_lowervp) {
acde96db 395 error = VFS_STATFS(um->um_lowervp->v_mount, &mstat, cred);
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396 if (error)
397 return (error);
398 }
399
400 /* now copy across the "interesting" information and fake the rest */
401#if 0
402 sbp->f_type = mstat.f_type;
403 sbp->f_flags = mstat.f_flags;
404 sbp->f_bsize = mstat.f_bsize;
405 sbp->f_iosize = mstat.f_iosize;
406#endif
407 lbsize = mstat.f_bsize;
408 sbp->f_blocks = mstat.f_blocks;
409 sbp->f_bfree = mstat.f_bfree;
410 sbp->f_bavail = mstat.f_bavail;
411 sbp->f_files = mstat.f_files;
412 sbp->f_ffree = mstat.f_ffree;
413
acde96db 414 error = VFS_STATFS(um->um_uppervp->v_mount, &mstat, cred);
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415 if (error)
416 return (error);
417
418 sbp->f_flags = mstat.f_flags;
419 sbp->f_bsize = mstat.f_bsize;
420 sbp->f_iosize = mstat.f_iosize;
421
422 /*
423 * if the lower and upper blocksizes differ, then frig the
424 * block counts so that the sizes reported by df make some
425 * kind of sense. none of this makes sense though.
426 */
427
428 if (mstat.f_bsize != lbsize)
429 sbp->f_blocks = ((off_t) sbp->f_blocks * lbsize) / mstat.f_bsize;
430
431 /*
432 * The "total" fields count total resources in all layers,
433 * the "free" fields count only those resources which are
434 * free in the upper layer (since only the upper layer
435 * is writeable).
436 */
437 sbp->f_blocks += mstat.f_blocks;
438 sbp->f_bfree = mstat.f_bfree;
439 sbp->f_bavail = mstat.f_bavail;
440 sbp->f_files += mstat.f_files;
441 sbp->f_ffree = mstat.f_ffree;
442
443 if (sbp != &mp->mnt_stat) {
444 sbp->f_type = mp->mnt_vfc->vfc_typenum;
445 bcopy(&mp->mnt_stat.f_fsid, &sbp->f_fsid, sizeof(sbp->f_fsid));
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446 bcopy(mp->mnt_stat.f_mntfromname, sbp->f_mntfromname, MNAMELEN);
447 }
448 return (0);
449}
450
451static struct vfsops union_vfsops = {
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452 .vfs_mount = union_mount,
453 .vfs_unmount = union_unmount,
454 .vfs_root = union_root,
455 .vfs_statfs = union_statfs,
456 .vfs_sync = vfs_stdsync,
457 .vfs_init = union_init
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458};
459
460VFS_SET(union_vfsops, union, VFCF_LOOPBACK);