xref: /freebsd/sys/fs/unionfs/union_vfsops.c (revision 9162f64b58d01ec01481d60b6cdc06ffd8e8c7fc)
1 /*-
2  * Copyright (c) 1994, 1995 The Regents of the University of California.
3  * Copyright (c) 1994, 1995 Jan-Simon Pendry.
4  * Copyright (c) 2005, 2006 Masanori Ozawa <ozawa@ongs.co.jp>, ONGS Inc.
5  * Copyright (c) 2006 Daichi Goto <daichi@freebsd.org>
6  * All rights reserved.
7  *
8  * This code is derived from software donated to Berkeley by
9  * Jan-Simon Pendry.
10  *
11  * Redistribution and use in source and binary forms, with or without
12  * modification, are permitted provided that the following conditions
13  * are met:
14  * 1. Redistributions of source code must retain the above copyright
15  *    notice, this list of conditions and the following disclaimer.
16  * 2. Redistributions in binary form must reproduce the above copyright
17  *    notice, this list of conditions and the following disclaimer in the
18  *    documentation and/or other materials provided with the distribution.
19  * 4. Neither the name of the University nor the names of its contributors
20  *    may be used to endorse or promote products derived from this software
21  *    without specific prior written permission.
22  *
23  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33  * SUCH DAMAGE.
34  *
35  *	@(#)union_vfsops.c	8.20 (Berkeley) 5/20/95
36  * $FreeBSD$
37  */
38 
39 #include <sys/param.h>
40 #include <sys/systm.h>
41 #include <sys/kdb.h>
42 #include <sys/fcntl.h>
43 #include <sys/kernel.h>
44 #include <sys/lock.h>
45 #include <sys/malloc.h>
46 #include <sys/mount.h>
47 #include <sys/namei.h>
48 #include <sys/proc.h>
49 #include <sys/vnode.h>
50 #include <sys/stat.h>
51 
52 #include <fs/unionfs/union.h>
53 
54 static MALLOC_DEFINE(M_UNIONFSMNT, "UNIONFS mount", "UNIONFS mount structure");
55 
56 static vfs_fhtovp_t	unionfs_fhtovp;
57 static vfs_checkexp_t	unionfs_checkexp;
58 static vfs_mount_t	unionfs_domount;
59 static vfs_quotactl_t	unionfs_quotactl;
60 static vfs_root_t	unionfs_root;
61 static vfs_sync_t	unionfs_sync;
62 static vfs_statfs_t	unionfs_statfs;
63 static vfs_unmount_t	unionfs_unmount;
64 static vfs_vget_t	unionfs_vget;
65 static vfs_extattrctl_t	unionfs_extattrctl;
66 
67 static struct vfsops unionfs_vfsops;
68 
69 /*
70  * Mount unionfs layer.
71  */
72 static int
73 unionfs_domount(struct mount *mp, struct thread *td)
74 {
75 	int		error;
76 	struct vnode   *lowerrootvp;
77 	struct vnode   *upperrootvp;
78 	struct unionfs_mount *ump;
79 	char           *target;
80 	char           *tmp;
81 	char           *ep;
82 	int		len;
83 	size_t		done;
84 	int		below;
85 	uid_t		uid;
86 	gid_t		gid;
87 	u_short		udir;
88 	u_short		ufile;
89 	unionfs_copymode copymode;
90 	unionfs_whitemode whitemode;
91 	struct componentname fakecn;
92 	struct nameidata nd, *ndp;
93 	struct vattr	va;
94 
95 	UNIONFSDEBUG("unionfs_mount(mp = %p)\n", (void *)mp);
96 
97 	error = 0;
98 	below = 0;
99 	uid = 0;
100 	gid = 0;
101 	udir = 0;
102 	ufile = 0;
103 	copymode = UNIONFS_TRANSPARENT;	/* default */
104 	whitemode = UNIONFS_WHITE_ALWAYS;
105 	ndp = &nd;
106 
107 	if (mp->mnt_flag & MNT_ROOTFS) {
108 		vfs_mount_error(mp, "Cannot union mount root filesystem");
109 		return (EOPNOTSUPP);
110 	}
111 
112 	/*
113 	 * Update is a no operation.
114 	 */
115 	if (mp->mnt_flag & MNT_UPDATE) {
116 		vfs_mount_error(mp, "unionfs does not support mount update");
117 		return (EOPNOTSUPP);
118 	}
119 
120 	/*
121 	 * Get argument
122 	 */
123 	error = vfs_getopt(mp->mnt_optnew, "target", (void **)&target, &len);
124 	if (error)
125 		error = vfs_getopt(mp->mnt_optnew, "from", (void **)&target,
126 		    &len);
127 	if (error || target[len - 1] != '\0') {
128 		vfs_mount_error(mp, "Invalid target");
129 		return (EINVAL);
130 	}
131 	if (vfs_getopt(mp->mnt_optnew, "below", NULL, NULL) == 0)
132 		below = 1;
133 	if (vfs_getopt(mp->mnt_optnew, "udir", (void **)&tmp, NULL) == 0) {
134 		if (tmp != NULL)
135 			udir = (mode_t)strtol(tmp, &ep, 8);
136 		if (tmp == NULL || *ep) {
137 			vfs_mount_error(mp, "Invalid udir");
138 			return (EINVAL);
139 		}
140 		udir &= S_IRWXU | S_IRWXG | S_IRWXO;
141 	}
142 	if (vfs_getopt(mp->mnt_optnew, "ufile", (void **)&tmp, NULL) == 0) {
143 		if (tmp != NULL)
144 			ufile = (mode_t)strtol(tmp, &ep, 8);
145 		if (tmp == NULL || *ep) {
146 			vfs_mount_error(mp, "Invalid ufile");
147 			return (EINVAL);
148 		}
149 		ufile &= S_IRWXU | S_IRWXG | S_IRWXO;
150 	}
151 	/* check umask, uid and gid */
152 	if (udir == 0 && ufile != 0)
153 		udir = ufile;
154 	if (ufile == 0 && udir != 0)
155 		ufile = udir;
156 
157 	vn_lock(mp->mnt_vnodecovered, LK_SHARED | LK_RETRY);
158 	error = VOP_GETATTR(mp->mnt_vnodecovered, &va, mp->mnt_cred);
159 	if (!error) {
160 		if (udir == 0)
161 			udir = va.va_mode;
162 		if (ufile == 0)
163 			ufile = va.va_mode;
164 		uid = va.va_uid;
165 		gid = va.va_gid;
166 	}
167 	VOP_UNLOCK(mp->mnt_vnodecovered, 0);
168 	if (error)
169 		return (error);
170 
171 	if (mp->mnt_cred->cr_ruid == 0) {	/* root only */
172 		if (vfs_getopt(mp->mnt_optnew, "uid", (void **)&tmp,
173 		    NULL) == 0) {
174 			if (tmp != NULL)
175 				uid = (uid_t)strtol(tmp, &ep, 10);
176 			if (tmp == NULL || *ep) {
177 				vfs_mount_error(mp, "Invalid uid");
178 				return (EINVAL);
179 			}
180 		}
181 		if (vfs_getopt(mp->mnt_optnew, "gid", (void **)&tmp,
182 		    NULL) == 0) {
183 			if (tmp != NULL)
184 				gid = (gid_t)strtol(tmp, &ep, 10);
185 			if (tmp == NULL || *ep) {
186 				vfs_mount_error(mp, "Invalid gid");
187 				return (EINVAL);
188 			}
189 		}
190 		if (vfs_getopt(mp->mnt_optnew, "copymode", (void **)&tmp,
191 		    NULL) == 0) {
192 			if (tmp == NULL) {
193 				vfs_mount_error(mp, "Invalid copymode");
194 				return (EINVAL);
195 			} else if (strcasecmp(tmp, "traditional") == 0)
196 				copymode = UNIONFS_TRADITIONAL;
197 			else if (strcasecmp(tmp, "transparent") == 0)
198 				copymode = UNIONFS_TRANSPARENT;
199 			else if (strcasecmp(tmp, "masquerade") == 0)
200 				copymode = UNIONFS_MASQUERADE;
201 			else {
202 				vfs_mount_error(mp, "Invalid copymode");
203 				return (EINVAL);
204 			}
205 		}
206 		if (vfs_getopt(mp->mnt_optnew, "whiteout", (void **)&tmp,
207 		    NULL) == 0) {
208 			if (tmp == NULL) {
209 				vfs_mount_error(mp, "Invalid whiteout mode");
210 				return (EINVAL);
211 			} else if (strcasecmp(tmp, "always") == 0)
212 				whitemode = UNIONFS_WHITE_ALWAYS;
213 			else if (strcasecmp(tmp, "whenneeded") == 0)
214 				whitemode = UNIONFS_WHITE_WHENNEEDED;
215 			else {
216 				vfs_mount_error(mp, "Invalid whiteout mode");
217 				return (EINVAL);
218 			}
219 		}
220 	}
221 	/* If copymode is UNIONFS_TRADITIONAL, uid/gid is mounted user. */
222 	if (copymode == UNIONFS_TRADITIONAL) {
223 		uid = mp->mnt_cred->cr_ruid;
224 		gid = mp->mnt_cred->cr_rgid;
225 	}
226 
227 	UNIONFSDEBUG("unionfs_mount: uid=%d, gid=%d\n", uid, gid);
228 	UNIONFSDEBUG("unionfs_mount: udir=0%03o, ufile=0%03o\n", udir, ufile);
229 	UNIONFSDEBUG("unionfs_mount: copymode=%d\n", copymode);
230 
231 	/*
232 	 * Find upper node
233 	 */
234 	NDINIT(ndp, LOOKUP, FOLLOW | LOCKLEAF, UIO_SYSSPACE, target, td);
235 	if ((error = namei(ndp)))
236 		return (error);
237 
238 	NDFREE(ndp, NDF_ONLY_PNBUF);
239 
240 	/* get root vnodes */
241 	lowerrootvp = mp->mnt_vnodecovered;
242 	upperrootvp = ndp->ni_vp;
243 
244 	/* create unionfs_mount */
245 	ump = (struct unionfs_mount *)malloc(sizeof(struct unionfs_mount),
246 	    M_UNIONFSMNT, M_WAITOK | M_ZERO);
247 
248 	/*
249 	 * Save reference
250 	 */
251 	if (below) {
252 		VOP_UNLOCK(upperrootvp, 0);
253 		vn_lock(lowerrootvp, LK_EXCLUSIVE | LK_RETRY);
254 		ump->um_lowervp = upperrootvp;
255 		ump->um_uppervp = lowerrootvp;
256 	} else {
257 		ump->um_lowervp = lowerrootvp;
258 		ump->um_uppervp = upperrootvp;
259 	}
260 	ump->um_rootvp = NULLVP;
261 	ump->um_uid = uid;
262 	ump->um_gid = gid;
263 	ump->um_udir = udir;
264 	ump->um_ufile = ufile;
265 	ump->um_copymode = copymode;
266 	ump->um_whitemode = whitemode;
267 
268 	MNT_ILOCK(mp);
269 	if ((lowerrootvp->v_mount->mnt_kern_flag & MNTK_MPSAFE) &&
270 	    (upperrootvp->v_mount->mnt_kern_flag & MNTK_MPSAFE))
271 		mp->mnt_kern_flag |= MNTK_MPSAFE;
272 	MNT_IUNLOCK(mp);
273 	mp->mnt_data = ump;
274 
275 	/*
276 	 * Copy upper layer's RDONLY flag.
277 	 */
278 	mp->mnt_flag |= ump->um_uppervp->v_mount->mnt_flag & MNT_RDONLY;
279 
280 	/*
281 	 * Check whiteout
282 	 */
283 	if ((mp->mnt_flag & MNT_RDONLY) == 0) {
284 		memset(&fakecn, 0, sizeof(fakecn));
285 		fakecn.cn_nameiop = LOOKUP;
286 		fakecn.cn_thread = td;
287 		error = VOP_WHITEOUT(ump->um_uppervp, &fakecn, LOOKUP);
288 		if (error) {
289 			if (below) {
290 				VOP_UNLOCK(ump->um_uppervp, 0);
291 				vrele(upperrootvp);
292 			} else
293 				vput(ump->um_uppervp);
294 			free(ump, M_UNIONFSMNT);
295 			mp->mnt_data = NULL;
296 			return (error);
297 		}
298 	}
299 
300 	/*
301 	 * Unlock the node
302 	 */
303 	VOP_UNLOCK(ump->um_uppervp, 0);
304 
305 	/*
306 	 * Get the unionfs root vnode.
307 	 */
308 	error = unionfs_nodeget(mp, ump->um_uppervp, ump->um_lowervp,
309 	    NULLVP, &(ump->um_rootvp), NULL, td);
310 	vrele(upperrootvp);
311 	if (error) {
312 		free(ump, M_UNIONFSMNT);
313 		mp->mnt_data = NULL;
314 		return (error);
315 	}
316 
317 	/*
318 	 * Check mnt_flag
319 	 */
320 	if ((ump->um_lowervp->v_mount->mnt_flag & MNT_LOCAL) &&
321 	    (ump->um_uppervp->v_mount->mnt_flag & MNT_LOCAL))
322 		mp->mnt_flag |= MNT_LOCAL;
323 
324 	/*
325 	 * Get new fsid
326 	 */
327 	vfs_getnewfsid(mp);
328 
329 	len = MNAMELEN - 1;
330 	tmp = mp->mnt_stat.f_mntfromname;
331 	copystr((below ? "<below>:" : "<above>:"), tmp, len, &done);
332 	len -= done - 1;
333 	tmp += done - 1;
334 	copystr(target, tmp, len, NULL);
335 
336 	UNIONFSDEBUG("unionfs_mount: from %s, on %s\n",
337 	    mp->mnt_stat.f_mntfromname, mp->mnt_stat.f_mntonname);
338 
339 	return (0);
340 }
341 
342 /*
343  * Free reference to unionfs layer
344  */
345 static int
346 unionfs_unmount(struct mount *mp, int mntflags, struct thread *td)
347 {
348 	struct unionfs_mount *ump;
349 	int		error;
350 	int		num;
351 	int		freeing;
352 	int		flags;
353 
354 	UNIONFSDEBUG("unionfs_unmount: mp = %p\n", (void *)mp);
355 
356 	ump = MOUNTTOUNIONFSMOUNT(mp);
357 	flags = 0;
358 
359 	if (mntflags & MNT_FORCE)
360 		flags |= FORCECLOSE;
361 
362 	/* vflush (no need to call vrele) */
363 	for (freeing = 0; (error = vflush(mp, 1, flags, td)) != 0;) {
364 		num = mp->mnt_nvnodelistsize;
365 		if (num == freeing)
366 			break;
367 		freeing = num;
368 	}
369 
370 	if (error)
371 		return (error);
372 
373 	free(ump, M_UNIONFSMNT);
374 	mp->mnt_data = 0;
375 
376 	return (0);
377 }
378 
379 static int
380 unionfs_root(struct mount *mp, int flags, struct vnode **vpp, struct thread *td)
381 {
382 	struct unionfs_mount *ump;
383 	struct vnode   *vp;
384 
385 	ump = MOUNTTOUNIONFSMOUNT(mp);
386 	vp = ump->um_rootvp;
387 
388 	UNIONFSDEBUG("unionfs_root: rootvp=%p locked=%x\n",
389 	    vp, VOP_ISLOCKED(vp));
390 
391 	vref(vp);
392 	if (flags & LK_TYPE_MASK)
393 		vn_lock(vp, flags);
394 
395 	*vpp = vp;
396 
397 	return (0);
398 }
399 
400 static int
401 unionfs_quotactl(struct mount *mp, int cmd, uid_t uid, void *arg,
402     struct thread *td)
403 {
404 	struct unionfs_mount *ump;
405 
406 	ump = MOUNTTOUNIONFSMOUNT(mp);
407 
408 	/*
409 	 * Writing is always performed to upper vnode.
410 	 */
411 	return (VFS_QUOTACTL(ump->um_uppervp->v_mount, cmd, uid, arg, td));
412 }
413 
414 static int
415 unionfs_statfs(struct mount *mp, struct statfs *sbp, struct thread *td)
416 {
417 	struct unionfs_mount *ump;
418 	int		error;
419 	struct statfs	mstat;
420 	uint64_t	lbsize;
421 
422 	ump = MOUNTTOUNIONFSMOUNT(mp);
423 
424 	UNIONFSDEBUG("unionfs_statfs(mp = %p, lvp = %p, uvp = %p)\n",
425 	    (void *)mp, (void *)ump->um_lowervp, (void *)ump->um_uppervp);
426 
427 	bzero(&mstat, sizeof(mstat));
428 
429 	error = VFS_STATFS(ump->um_lowervp->v_mount, &mstat, td);
430 	if (error)
431 		return (error);
432 
433 	/* now copy across the "interesting" information and fake the rest */
434 	sbp->f_blocks = mstat.f_blocks;
435 	sbp->f_files = mstat.f_files;
436 
437 	lbsize = mstat.f_bsize;
438 
439 	error = VFS_STATFS(ump->um_uppervp->v_mount, &mstat, td);
440 	if (error)
441 		return (error);
442 
443 	/*
444 	 * The FS type etc is copy from upper vfs.
445 	 * (write able vfs have priority)
446 	 */
447 	sbp->f_type = mstat.f_type;
448 	sbp->f_flags = mstat.f_flags;
449 	sbp->f_bsize = mstat.f_bsize;
450 	sbp->f_iosize = mstat.f_iosize;
451 
452 	if (mstat.f_bsize != lbsize)
453 		sbp->f_blocks = ((off_t)sbp->f_blocks * lbsize) / mstat.f_bsize;
454 
455 	sbp->f_blocks += mstat.f_blocks;
456 	sbp->f_bfree = mstat.f_bfree;
457 	sbp->f_bavail = mstat.f_bavail;
458 	sbp->f_files += mstat.f_files;
459 	sbp->f_ffree = mstat.f_ffree;
460 	return (0);
461 }
462 
463 static int
464 unionfs_sync(struct mount *mp, int waitfor, struct thread *td)
465 {
466 	/* nothing to do */
467 	return (0);
468 }
469 
470 static int
471 unionfs_vget(struct mount *mp, ino_t ino, int flags, struct vnode **vpp)
472 {
473 	return (EOPNOTSUPP);
474 }
475 
476 static int
477 unionfs_fhtovp(struct mount *mp, struct fid *fidp, struct vnode **vpp)
478 {
479 	return (EOPNOTSUPP);
480 }
481 
482 static int
483 unionfs_checkexp(struct mount *mp, struct sockaddr *nam, int *extflagsp,
484     struct ucred **credanonp, int *numsecflavors, int **secflavors)
485 {
486 	return (EOPNOTSUPP);
487 }
488 
489 static int
490 unionfs_extattrctl(struct mount *mp, int cmd, struct vnode *filename_vp,
491     int namespace, const char *attrname, struct thread *td)
492 {
493 	struct unionfs_mount *ump;
494 	struct unionfs_node *unp;
495 
496 	ump = MOUNTTOUNIONFSMOUNT(mp);
497 	unp = VTOUNIONFS(filename_vp);
498 
499 	if (unp->un_uppervp != NULLVP) {
500 		return (VFS_EXTATTRCTL(ump->um_uppervp->v_mount, cmd,
501 		    unp->un_uppervp, namespace, attrname, td));
502 	} else {
503 		return (VFS_EXTATTRCTL(ump->um_lowervp->v_mount, cmd,
504 		    unp->un_lowervp, namespace, attrname, td));
505 	}
506 }
507 
508 static struct vfsops unionfs_vfsops = {
509 	.vfs_checkexp =		unionfs_checkexp,
510 	.vfs_extattrctl =	unionfs_extattrctl,
511 	.vfs_fhtovp =		unionfs_fhtovp,
512 	.vfs_init =		unionfs_init,
513 	.vfs_mount =		unionfs_domount,
514 	.vfs_quotactl =		unionfs_quotactl,
515 	.vfs_root =		unionfs_root,
516 	.vfs_statfs =		unionfs_statfs,
517 	.vfs_sync =		unionfs_sync,
518 	.vfs_uninit =		unionfs_uninit,
519 	.vfs_unmount =		unionfs_unmount,
520 	.vfs_vget =		unionfs_vget,
521 };
522 
523 VFS_SET(unionfs_vfsops, unionfs, VFCF_LOOPBACK);
524