![[BACK]](/cvsweb/icons/back.gif){kind=icon}
Return to union_vfsops.c CVS log ![[TXT]](/cvsweb/icons/text.gif){kind=icon}
![[DIR]](/cvsweb/icons/dir.gif){kind=icon}
Up to [Apple XNU] / XNU / bsd / miscfs / union|
Return to union_vfsops.c CVS log | Up to [Apple XNU] / XNU / bsd / miscfs / union |
1.1 root 1: /*
2: * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
3: *
4: * @APPLE_LICENSE_HEADER_START@
5: *
6: * The contents of this file constitute Original Code as defined in and
7: * are subject to the Apple Public Source License Version 1.1 (the
8: * "License"). You may not use this file except in compliance with the
9: * License. Please obtain a copy of the License at
10: * http://www.apple.com/publicsource and read it before using this file.
11: *
12: * This Original Code and all software distributed under the License are
13: * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
14: * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
15: * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
16: * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT. Please see the
17: * License for the specific language governing rights and limitations
18: * under the License.
19: *
20: * @APPLE_LICENSE_HEADER_END@
21: */
22: /* Copyright (c) 1995 NeXT Computer, Inc. All Rights Reserved */
23: /*
24: * Copyright (c) 1994, 1995 The Regents of the University of California.
25: * Copyright (c) 1994, 1995 Jan-Simon Pendry.
26: * All rights reserved.
27: *
28: * This code is derived from software donated to Berkeley by
29: * Jan-Simon Pendry.
30: *
31: * Redistribution and use in source and binary forms, with or without
32: * modification, are permitted provided that the following conditions
33: * are met:
34: * 1. Redistributions of source code must retain the above copyright
35: * notice, this list of conditions and the following disclaimer.
36: * 2. Redistributions in binary form must reproduce the above copyright
37: * notice, this list of conditions and the following disclaimer in the
38: * documentation and/or other materials provided with the distribution.
39: * 3. All advertising materials mentioning features or use of this software
40: * must display the following acknowledgement:
41: * This product includes software developed by the University of
42: * California, Berkeley and its contributors.
43: * 4. Neither the name of the University nor the names of its contributors
44: * may be used to endorse or promote products derived from this software
45: * without specific prior written permission.
46: *
47: * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
48: * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
49: * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
50: * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
51: * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
52: * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
53: * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
54: * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
55: * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
56: * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
57: * SUCH DAMAGE.
58: *
59: * @(#)union_vfsops.c 8.20 (Berkeley) 5/20/95
60: */
61:
62: /*
63: * Union Layer
64: */
65:
66: #include <sys/param.h>
67: #include <sys/systm.h>
68: #include <sys/time.h>
69: #include <sys/types.h>
70: #include <sys/proc.h>
71: #include <sys/vnode.h>
72: #include <sys/mount.h>
73: #include <sys/namei.h>
74: #include <sys/malloc.h>
75: #include <sys/filedesc.h>
76: #include <sys/queue.h>
77: #include <miscfs/union/union.h>
78:
79: /*
80: * Mount union filesystem
81: */
82: int
83: union_mount(mp, path, data, ndp, p)
84: struct mount *mp;
85: char *path;
86: caddr_t data;
87: struct nameidata *ndp;
88: struct proc *p;
89: {
90: int error = 0;
91: struct union_args args;
92: struct vnode *lowerrootvp = NULLVP;
93: struct vnode *upperrootvp = NULLVP;
94: struct union_mount *um = 0;
95: struct ucred *cred = 0;
96: struct ucred *scred;
97: struct vattr va;
98: char *cp;
99: int len;
100: u_int size;
101:
102: #ifdef UNION_DIAGNOSTIC
103: printf("union_mount(mp = %x)\n", mp);
104: #endif
105:
106: /*
107: * Update is a no-op
108: */
109: if (mp->mnt_flag & MNT_UPDATE) {
110: /*
111: * Need to provide.
112: * 1. a way to convert between rdonly and rdwr mounts.
113: * 2. support for nfs exports.
114: */
115: error = EOPNOTSUPP;
116: goto bad;
117: }
118:
119: /*
120: * Get argument
121: */
122: if (error = copyin(data, (caddr_t)&args, sizeof(struct union_args)))
123: goto bad;
124:
125: lowerrootvp = mp->mnt_vnodecovered;
126: VREF(lowerrootvp);
127:
128: /*
129: * Find upper node.
130: */
131: NDINIT(ndp, LOOKUP, FOLLOW|WANTPARENT,
132: UIO_USERSPACE, args.target, p);
133:
134: if (error = namei(ndp))
135: goto bad;
136:
137: upperrootvp = ndp->ni_vp;
138: vrele(ndp->ni_dvp);
139: ndp->ni_dvp = NULL;
140:
141: if (upperrootvp->v_type != VDIR) {
142: error = EINVAL;
143: goto bad;
144: }
145:
146: // um = (struct union_mount *) malloc(sizeof(struct union_mount),
147: // M_UFSMNT, M_WAITOK); /* XXX */
148: MALLOC(um, struct union_mount *, sizeof(struct union_mount),
149: M_UFSMNT, M_WAITOK);
150:
151: /*
152: * Keep a held reference to the target vnodes.
153: * They are vrele'd in union_unmount.
154: *
155: * Depending on the _BELOW flag, the filesystems are
156: * viewed in a different order. In effect, this is the
157: * same as providing a mount under option to the mount syscall.
158: */
159:
160: um->um_op = args.mntflags & UNMNT_OPMASK;
161: switch (um->um_op) {
162: case UNMNT_ABOVE:
163: um->um_lowervp = lowerrootvp;
164: um->um_uppervp = upperrootvp;
165: break;
166:
167: case UNMNT_BELOW:
168: um->um_lowervp = upperrootvp;
169: um->um_uppervp = lowerrootvp;
170: break;
171:
172: case UNMNT_REPLACE:
173: vrele(lowerrootvp);
174: lowerrootvp = NULLVP;
175: um->um_uppervp = upperrootvp;
176: um->um_lowervp = lowerrootvp;
177: break;
178:
179: default:
180: error = EINVAL;
181: goto bad;
182: }
183:
184: /*
185: * Unless the mount is readonly, ensure that the top layer
186: * supports whiteout operations
187: */
188: if ((mp->mnt_flag & MNT_RDONLY) == 0) {
189: error = VOP_WHITEOUT(um->um_uppervp, (struct componentname *) 0, LOOKUP);
190: if (error)
191: goto bad;
192: }
193:
194: um->um_cred = p->p_ucred;
195: crhold(um->um_cred);
196: um->um_cmode = UN_DIRMODE &~ p->p_fd->fd_cmask;
197:
198: /*
199: * Depending on what you think the MNT_LOCAL flag might mean,
200: * you may want the && to be || on the conditional below.
201: * At the moment it has been defined that the filesystem is
202: * only local if it is all local, ie the MNT_LOCAL flag implies
203: * that the entire namespace is local. If you think the MNT_LOCAL
204: * flag implies that some of the files might be stored locally
205: * then you will want to change the conditional.
206: */
207: if (um->um_op == UNMNT_ABOVE) {
208: if (((um->um_lowervp == NULLVP) ||
209: (um->um_lowervp->v_mount->mnt_flag & MNT_LOCAL)) &&
210: (um->um_uppervp->v_mount->mnt_flag & MNT_LOCAL))
211: mp->mnt_flag |= MNT_LOCAL;
212: }
213:
214: /*
215: * Copy in the upper layer's RDONLY flag. This is for the benefit
216: * of lookup() which explicitly checks the flag, rather than asking
217: * the filesystem for it's own opinion. This means, that an update
218: * mount of the underlying filesystem to go from rdonly to rdwr
219: * will leave the unioned view as read-only.
220: */
221: mp->mnt_flag |= (um->um_uppervp->v_mount->mnt_flag & MNT_RDONLY);
222:
223: mp->mnt_data = (qaddr_t) um;
224: vfs_getnewfsid(mp);
225:
226: (void) copyinstr(path, mp->mnt_stat.f_mntonname, MNAMELEN - 1, &size);
227: bzero(mp->mnt_stat.f_mntonname + size, MNAMELEN - size);
228:
229: switch (um->um_op) {
230: case UNMNT_ABOVE:
231: cp = "<above>:";
232: break;
233: case UNMNT_BELOW:
234: cp = "<below>:";
235: break;
236: case UNMNT_REPLACE:
237: cp = "";
238: break;
239: }
240: len = strlen(cp);
241: bcopy(cp, mp->mnt_stat.f_mntfromname, len);
242:
243: cp = mp->mnt_stat.f_mntfromname + len;
244: len = MNAMELEN - len;
245:
246: (void) copyinstr(args.target, cp, len - 1, &size);
247: bzero(cp + size, len - size);
248:
249: #ifdef UNION_DIAGNOSTIC
250: printf("union_mount: from %s, on %s\n",
251: mp->mnt_stat.f_mntfromname, mp->mnt_stat.f_mntonname);
252: #endif
253: return (0);
254:
255: bad:
256: if (um)
257: _FREE(um, M_UFSMNT);
258: if (cred != NOCRED)
259: crfree(cred);
260: if (upperrootvp)
261: vrele(upperrootvp);
262: if (lowerrootvp)
263: vrele(lowerrootvp);
264: return (error);
265: }
266:
267: /*
268: * VFS start. Nothing needed here - the start routine
269: * on the underlying filesystem(s) will have been called
270: * when that filesystem was mounted.
271: */
272: int
273: union_start(mp, flags, p)
274: struct mount *mp;
275: int flags;
276: struct proc *p;
277: {
278:
279: return (0);
280: }
281:
282: /*
283: * Free reference to union layer
284: */
285: int
286: union_unmount(mp, mntflags, p)
287: struct mount *mp;
288: int mntflags;
289: struct proc *p;
290: {
291: struct union_mount *um = MOUNTTOUNIONMOUNT(mp);
292: struct vnode *um_rootvp;
293: int error;
294: int freeing;
295: int flags = 0;
296: struct ucred *cred;
297:
298: #ifdef UNION_DIAGNOSTIC
299: printf("union_unmount(mp = %x)\n", mp);
300: #endif
301:
302: if (mntflags & MNT_FORCE)
303: flags |= FORCECLOSE;
304:
305: if (error = union_root(mp, &um_rootvp))
306: return (error);
307:
308: /*
309: * Keep flushing vnodes from the mount list.
310: * This is needed because of the un_pvp held
311: * reference to the parent vnode.
312: * If more vnodes have been freed on a given pass,
313: * the try again. The loop will iterate at most
314: * (d) times, where (d) is the maximum tree depth
315: * in the filesystem.
316: */
317: for (freeing = 0; vflush(mp, um_rootvp, flags) != 0;) {
318: struct vnode *vp;
319: int n;
320:
321: /* count #vnodes held on mount list */
322: for (n = 0, vp = mp->mnt_vnodelist.lh_first;
323: vp != NULLVP;
324: vp = vp->v_mntvnodes.le_next)
325: n++;
326:
327: /* if this is unchanged then stop */
328: if (n == freeing)
329: break;
330:
331: /* otherwise try once more time */
332: freeing = n;
333: }
334:
335: /* At this point the root vnode should have a single reference */
336: if (um_rootvp->v_usecount > 1) {
337: vput(um_rootvp);
338: return (EBUSY);
339: }
340:
341: #ifdef UNION_DIAGNOSTIC
342: vprint("union root", um_rootvp);
343: #endif
344: /*
345: * Discard references to upper and lower target vnodes.
346: */
347: if (um->um_lowervp)
348: vrele(um->um_lowervp);
349: vrele(um->um_uppervp);
350: cred = um->um_cred;
351: if (cred != NOCRED) {
352: um->um_cred = NOCRED;
353: crfree(cred);
354: }
355: /*
356: * Release reference on underlying root vnode
357: */
358: vput(um_rootvp);
359: /*
360: * And blow it away for future re-use
361: */
362: vgone(um_rootvp);
363: /*
364: * Finally, throw away the union_mount structure
365: */
366: _FREE(mp->mnt_data, M_UFSMNT); /* XXX */
367: mp->mnt_data = 0;
368: return (0);
369: }
370:
371: int
372: union_root(mp, vpp)
373: struct mount *mp;
374: struct vnode **vpp;
375: {
376: struct proc *p = current_proc(); /* XXX */
377: struct union_mount *um = MOUNTTOUNIONMOUNT(mp);
378: int error;
379: int loselock;
380:
381: /*
382: * Return locked reference to root.
383: */
384: VREF(um->um_uppervp);
385: if ((um->um_op == UNMNT_BELOW) &&
386: VOP_ISLOCKED(um->um_uppervp)) {
387: loselock = 1;
388: } else {
389: vn_lock(um->um_uppervp, LK_EXCLUSIVE | LK_RETRY, p);
390: loselock = 0;
391: }
392: if (um->um_lowervp)
393: VREF(um->um_lowervp);
394: error = union_allocvp(vpp, mp,
395: (struct vnode *) 0,
396: (struct vnode *) 0,
397: (struct componentname *) 0,
398: um->um_uppervp,
399: um->um_lowervp,
400: 1);
401:
402: if (error) {
403: if (loselock)
404: vrele(um->um_uppervp);
405: else
406: vput(um->um_uppervp);
407: if (um->um_lowervp)
408: vrele(um->um_lowervp);
409: } else {
410: if (loselock)
411: VTOUNION(*vpp)->un_flags &= ~UN_ULOCK;
412: }
413:
414: return (error);
415: }
416:
417: int
418: union_statfs(mp, sbp, p)
419: struct mount *mp;
420: struct statfs *sbp;
421: struct proc *p;
422: {
423: int error;
424: struct union_mount *um = MOUNTTOUNIONMOUNT(mp);
425: struct statfs mstat;
426: int lbsize;
427:
428: #ifdef UNION_DIAGNOSTIC
429: printf("union_statfs(mp = %x, lvp = %x, uvp = %x)\n", mp,
430: um->um_lowervp,
431: um->um_uppervp);
432: #endif
433:
434: bzero(&mstat, sizeof(mstat));
435:
436: if (um->um_lowervp) {
437: error = VFS_STATFS(um->um_lowervp->v_mount, &mstat, p);
438: if (error)
439: return (error);
440: }
441:
442: /* now copy across the "interesting" information and fake the rest */
443: #if 0
444: sbp->f_type = mstat.f_type;
445: sbp->f_flags = mstat.f_flags;
446: sbp->f_bsize = mstat.f_bsize;
447: sbp->f_iosize = mstat.f_iosize;
448: #endif
449: lbsize = mstat.f_bsize;
450: sbp->f_blocks = mstat.f_blocks;
451: sbp->f_bfree = mstat.f_bfree;
452: sbp->f_bavail = mstat.f_bavail;
453: sbp->f_files = mstat.f_files;
454: sbp->f_ffree = mstat.f_ffree;
455:
456: error = VFS_STATFS(um->um_uppervp->v_mount, &mstat, p);
457: if (error)
458: return (error);
459:
460: sbp->f_flags = mstat.f_flags;
461: sbp->f_bsize = mstat.f_bsize;
462: sbp->f_iosize = mstat.f_iosize;
463:
464: /*
465: * if the lower and upper blocksizes differ, then frig the
466: * block counts so that the sizes reported by df make some
467: * kind of sense. none of this makes sense though.
468: */
469:
470: if (mstat.f_bsize != lbsize)
471: sbp->f_blocks = sbp->f_blocks * lbsize / mstat.f_bsize;
472:
473: /*
474: * The "total" fields count total resources in all layers,
475: * the "free" fields count only those resources which are
476: * free in the upper layer (since only the upper layer
477: * is writeable).
478: */
479: sbp->f_blocks += mstat.f_blocks;
480: sbp->f_bfree = mstat.f_bfree;
481: sbp->f_bavail = mstat.f_bavail;
482: sbp->f_files += mstat.f_files;
483: sbp->f_ffree = mstat.f_ffree;
484:
485: if (sbp != &mp->mnt_stat) {
486: sbp->f_type = mp->mnt_vfc->vfc_typenum;
487: bcopy(&mp->mnt_stat.f_fsid, &sbp->f_fsid, sizeof(sbp->f_fsid));
488: bcopy(mp->mnt_stat.f_mntonname, sbp->f_mntonname, MNAMELEN);
489: bcopy(mp->mnt_stat.f_mntfromname, sbp->f_mntfromname, MNAMELEN);
490: }
491: return (0);
492: }
493:
494: /*
495: * XXX - Assumes no data cached at union layer.
496: */
497: #define union_sync ((int (*) __P((struct mount *, int, struct ucred *, \
498: struct proc *)))nullop)
499:
500: #define union_fhtovp ((int (*) __P((struct mount *, struct fid *, \
501: struct mbuf *, struct vnode **, int *, struct ucred **)))eopnotsupp)
502: int union_init __P((struct vfsconf *));
503: #define union_quotactl ((int (*) __P((struct mount *, int, uid_t, caddr_t, \
504: struct proc *)))eopnotsupp)
505: #define union_sysctl ((int (*) __P((int *, u_int, void *, size_t *, void *, \
506: size_t, struct proc *)))eopnotsupp)
507: #define union_vget ((int (*) __P((struct mount *, ino_t, struct vnode **))) \
508: eopnotsupp)
509: #define union_vptofh ((int (*) __P((struct vnode *, struct fid *)))eopnotsupp)
510:
511: struct vfsops union_vfsops = {
512: union_mount,
513: union_start,
514: union_unmount,
515: union_root,
516: union_quotactl,
517: union_statfs,
518: union_sync,
519: union_vget,
520: union_fhtovp,
521: union_vptofh,
522: union_init,
523: union_sysctl,
524: };
This archive runs on limited infrastructure. Preserving old code on modern bandwidth. Automated agents are requested to crawl responsibly.