1/* $NetBSD: layer_vnops.c,v 1.59 2016/08/20 12:37:09 hannken Exp $ */
2
3/*
4 * Copyright (c) 1999 National Aeronautics & Space Administration
5 * All rights reserved.
6 *
7 * This software was written by William Studenmund of the
8 * Numerical Aerospace Simulation Facility, NASA Ames Research Center.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 * 3. Neither the name of the National Aeronautics & Space Administration
19 * nor the names of its contributors may be used to endorse or promote
20 * products derived from this software without specific prior written
21 * permission.
22 *
23 * THIS SOFTWARE IS PROVIDED BY THE NATIONAL AERONAUTICS & SPACE ADMINISTRATION
24 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
25 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
26 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE ADMINISTRATION OR CONTRIB-
27 * UTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
28 * OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
29 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
30 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
31 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
32 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
33 * POSSIBILITY OF SUCH DAMAGE.
34 */
35
36/*
37 * Copyright (c) 1992, 1993
38 * The Regents of the University of California. All rights reserved.
39 *
40 * This code is derived from software contributed to Berkeley by
41 * John Heidemann of the UCLA Ficus project.
42 *
43 * Redistribution and use in source and binary forms, with or without
44 * modification, are permitted provided that the following conditions
45 * are met:
46 * 1. Redistributions of source code must retain the above copyright
47 * notice, this list of conditions and the following disclaimer.
48 * 2. Redistributions in binary form must reproduce the above copyright
49 * notice, this list of conditions and the following disclaimer in the
50 * documentation and/or other materials provided with the distribution.
51 * 3. Neither the name of the University nor the names of its contributors
52 * may be used to endorse or promote products derived from this software
53 * without specific prior written permission.
54 *
55 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
56 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
57 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
58 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
59 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
60 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
61 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
62 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
63 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
64 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
65 * SUCH DAMAGE.
66 *
67 * @(#)null_vnops.c 8.6 (Berkeley) 5/27/95
68 *
69 * Ancestors:
70 * @(#)lofs_vnops.c 1.2 (Berkeley) 6/18/92
71 * Id: lofs_vnops.c,v 1.11 1992/05/30 10:05:43 jsp Exp jsp
72 * ...and...
73 * @(#)null_vnodeops.c 1.20 92/07/07 UCLA Ficus project
74 */
75
76/*
77 * Generic layer vnode operations.
78 *
79 * The layer.h, layer_extern.h, layer_vfs.c, and layer_vnops.c files provide
80 * the core implementation of stacked file-systems.
81 *
82 * The layerfs duplicates a portion of the file system name space under
83 * a new name. In this respect, it is similar to the loopback file system.
84 * It differs from the loopback fs in two respects: it is implemented using
85 * a stackable layers technique, and it is "layerfs-nodes" stack above all
86 * lower-layer vnodes, not just over directory vnodes.
87 *
88 * OPERATION OF LAYERFS
89 *
90 * The layerfs is the minimum file system layer, bypassing all possible
91 * operations to the lower layer for processing there. The majority of its
92 * activity centers on the bypass routine, through which nearly all vnode
93 * operations pass.
94 *
95 * The bypass routine accepts arbitrary vnode operations for handling by
96 * the lower layer. It begins by examining vnode operation arguments and
97 * replacing any layered nodes by their lower-layer equivalents. It then
98 * invokes an operation on the lower layer. Finally, it replaces the
99 * layered nodes in the arguments and, if a vnode is returned by the
100 * operation, stacks a layered node on top of the returned vnode.
101 *
102 * The bypass routine in this file, layer_bypass(), is suitable for use
103 * by many different layered filesystems. It can be used by multiple
104 * filesystems simultaneously. Alternatively, a layered fs may provide
105 * its own bypass routine, in which case layer_bypass() should be used as
106 * a model. For instance, the main functionality provided by umapfs, the user
107 * identity mapping file system, is handled by a custom bypass routine.
108 *
109 * Typically a layered fs registers its selected bypass routine as the
110 * default vnode operation in its vnodeopv_entry_desc table. Additionally
111 * the filesystem must store the bypass entry point in the layerm_bypass
112 * field of struct layer_mount. All other layer routines in this file will
113 * use the layerm_bypass() routine.
114 *
115 * Although the bypass routine handles most operations outright, a number
116 * of operations are special cased and handled by the layerfs. For instance,
117 * layer_getattr() must change the fsid being returned. While layer_lock()
118 * and layer_unlock() must handle any locking for the current vnode as well
119 * as pass the lock request down. layer_inactive() and layer_reclaim() are
120 * not bypassed so that they can handle freeing layerfs-specific data. Also,
121 * certain vnode operations (create, mknod, remove, link, rename, mkdir,
122 * rmdir, and symlink) change the locking state within the operation. Ideally
123 * these operations should not change the lock state, but should be changed
124 * to let the caller of the function unlock them. Otherwise, all intermediate
125 * vnode layers (such as union, umapfs, etc) must catch these functions to do
126 * the necessary locking at their layer.
127 *
128 * INSTANTIATING VNODE STACKS
129 *
130 * Mounting associates "layerfs-nodes" stack and lower layer, in effect
131 * stacking two VFSes. The initial mount creates a single vnode stack for
132 * the root of the new layerfs. All other vnode stacks are created as a
133 * result of vnode operations on this or other layerfs vnode stacks.
134 *
135 * New vnode stacks come into existence as a result of an operation which
136 * returns a vnode. The bypass routine stacks a layerfs-node above the new
137 * vnode before returning it to the caller.
138 *
139 * For example, imagine mounting a null layer with:
140 *
141 * "mount_null /usr/include /dev/layer/null"
142 *
143 * Changing directory to /dev/layer/null will assign the root layerfs-node,
144 * which was created when the null layer was mounted). Now consider opening
145 * "sys". A layer_lookup() would be performed on the root layerfs-node.
146 * This operation would bypass through to the lower layer which would return
147 * a vnode representing the UFS "sys". Then, layer_bypass() builds a
148 * layerfs-node aliasing the UFS "sys" and returns this to the caller.
149 * Later operations on the layerfs-node "sys" will repeat this process when
150 * constructing other vnode stacks.
151 *
152 * INVOKING OPERATIONS ON LOWER LAYERS
153 *
154 * There are two techniques to invoke operations on a lower layer when the
155 * operation cannot be completely bypassed. Each method is appropriate in
156 * different situations. In both cases, it is the responsibility of the
157 * aliasing layer to make the operation arguments "correct" for the lower
158 * layer by mapping any vnode arguments to the lower layer.
159 *
160 * The first approach is to call the aliasing layer's bypass routine. This
161 * method is most suitable when you wish to invoke the operation currently
162 * being handled on the lower layer. It has the advantage that the bypass
163 * routine already must do argument mapping. An example of this is
164 * layer_getattr().
165 *
166 * A second approach is to directly invoke vnode operations on the lower
167 * layer with the VOP_OPERATIONNAME interface. The advantage of this method
168 * is that it is easy to invoke arbitrary operations on the lower layer.
169 * The disadvantage is that vnode's arguments must be manually mapped.
170 */
171
172#include <sys/cdefs.h>
173__KERNEL_RCSID(0, "$NetBSD: layer_vnops.c,v 1.59 2016/08/20 12:37:09 hannken Exp $");
174
175#include <sys/param.h>
176#include <sys/systm.h>
177#include <sys/proc.h>
178#include <sys/time.h>
179#include <sys/vnode.h>
180#include <sys/mount.h>
181#include <sys/namei.h>
182#include <sys/kmem.h>
183#include <sys/buf.h>
184#include <sys/kauth.h>
185
186#include <miscfs/genfs/layer.h>
187#include <miscfs/genfs/layer_extern.h>
188#include <miscfs/genfs/genfs.h>
189#include <miscfs/specfs/specdev.h>
190
191/*
192 * This is the 08-June-99 bypass routine, based on the 10-Apr-92 bypass
193 * routine by John Heidemann.
194 * The new element for this version is that the whole nullfs
195 * system gained the concept of locks on the lower node.
196 * The 10-Apr-92 version was optimized for speed, throwing away some
197 * safety checks. It should still always work, but it's not as
198 * robust to programmer errors.
199 *
200 * In general, we map all vnodes going down and unmap them on the way back.
201 *
202 * Also, some BSD vnode operations have the side effect of vrele'ing
203 * their arguments. With stacking, the reference counts are held
204 * by the upper node, not the lower one, so we must handle these
205 * side-effects here. This is not of concern in Sun-derived systems
206 * since there are no such side-effects.
207 *
208 * New for the 08-June-99 version: we also handle operations which unlock
209 * the passed-in node (typically they vput the node).
210 *
211 * This makes the following assumptions:
212 * - only one returned vpp
213 * - no INOUT vpp's (Sun's vop_open has one of these)
214 * - the vnode operation vector of the first vnode should be used
215 * to determine what implementation of the op should be invoked
216 * - all mapped vnodes are of our vnode-type (NEEDSWORK:
217 * problems on rmdir'ing mount points and renaming?)
218 */
219int
220layer_bypass(void *v)
221{
222 struct vop_generic_args /* {
223 struct vnodeop_desc *a_desc;
224 <other random data follows, presumably>
225 } */ *ap = v;
226 int (**our_vnodeop_p)(void *);
227 struct vnode **this_vp_p;
228 int error;
229 struct vnode *old_vps[VDESC_MAX_VPS], *vp0;
230 struct vnode **vps_p[VDESC_MAX_VPS];
231 struct vnode ***vppp;
232 struct mount *mp;
233 struct vnodeop_desc *descp = ap->a_desc;
234 int reles, i, flags;
235
236#ifdef DIAGNOSTIC
237 /*
238 * We require at least one vp.
239 */
240 if (descp->vdesc_vp_offsets == NULL ||
241 descp->vdesc_vp_offsets[0] == VDESC_NO_OFFSET)
242 panic("%s: no vp's in map.\n", __func__);
243#endif
244
245 vps_p[0] =
246 VOPARG_OFFSETTO(struct vnode**, descp->vdesc_vp_offsets[0], ap);
247 vp0 = *vps_p[0];
248 mp = vp0->v_mount;
249 flags = MOUNTTOLAYERMOUNT(mp)->layerm_flags;
250 our_vnodeop_p = vp0->v_op;
251
252 if (flags & LAYERFS_MBYPASSDEBUG)
253 printf("%s: %s\n", __func__, descp->vdesc_name);
254
255 /*
256 * Map the vnodes going in.
257 * Later, we'll invoke the operation based on
258 * the first mapped vnode's operation vector.
259 */
260 reles = descp->vdesc_flags;
261 for (i = 0; i < VDESC_MAX_VPS; reles >>= 1, i++) {
262 if (descp->vdesc_vp_offsets[i] == VDESC_NO_OFFSET)
263 break; /* bail out at end of list */
264 vps_p[i] = this_vp_p =
265 VOPARG_OFFSETTO(struct vnode**, descp->vdesc_vp_offsets[i],
266 ap);
267 /*
268 * We're not guaranteed that any but the first vnode
269 * are of our type. Check for and don't map any
270 * that aren't. (We must always map first vp or vclean fails.)
271 */
272 if (i && (*this_vp_p == NULL ||
273 (*this_vp_p)->v_op != our_vnodeop_p)) {
274 old_vps[i] = NULL;
275 } else {
276 old_vps[i] = *this_vp_p;
277 *(vps_p[i]) = LAYERVPTOLOWERVP(*this_vp_p);
278 /*
279 * XXX - Several operations have the side effect
280 * of vrele'ing their vp's. We must account for
281 * that. (This should go away in the future.)
282 */
283 if (reles & VDESC_VP0_WILLRELE)
284 vref(*this_vp_p);
285 }
286 }
287
288 /*
289 * Call the operation on the lower layer
290 * with the modified argument structure.
291 */
292 error = VCALL(*vps_p[0], descp->vdesc_offset, ap);
293
294 /*
295 * Maintain the illusion of call-by-value
296 * by restoring vnodes in the argument structure
297 * to their original value.
298 */
299 reles = descp->vdesc_flags;
300 for (i = 0; i < VDESC_MAX_VPS; reles >>= 1, i++) {
301 if (descp->vdesc_vp_offsets[i] == VDESC_NO_OFFSET)
302 break; /* bail out at end of list */
303 if (old_vps[i]) {
304 *(vps_p[i]) = old_vps[i];
305 if (reles & VDESC_VP0_WILLRELE)
306 vrele(*(vps_p[i]));
307 }
308 }
309
310 /*
311 * Map the possible out-going vpp
312 * (Assumes that the lower layer always returns
313 * a VREF'ed vpp unless it gets an error.)
314 */
315 if (descp->vdesc_vpp_offset != VDESC_NO_OFFSET && !error) {
316 vppp = VOPARG_OFFSETTO(struct vnode***,
317 descp->vdesc_vpp_offset, ap);
318 /*
319 * Only vop_lookup, vop_create, vop_makedir, vop_mknod
320 * and vop_symlink return vpp's. vop_lookup doesn't call bypass
321 * as a lookup on "." would generate a locking error.
322 * So all the calls which get us here have a unlocked vpp. :-)
323 */
324 error = layer_node_create(mp, **vppp, *vppp);
325 if (error) {
326 vrele(**vppp);
327 **vppp = NULL;
328 }
329 }
330 return error;
331}
332
333/*
334 * We have to carry on the locking protocol on the layer vnodes
335 * as we progress through the tree. We also have to enforce read-only
336 * if this layer is mounted read-only.
337 */
338int
339layer_lookup(void *v)
340{
341 struct vop_lookup_v2_args /* {
342 struct vnodeop_desc *a_desc;
343 struct vnode * a_dvp;
344 struct vnode ** a_vpp;
345 struct componentname * a_cnp;
346 } */ *ap = v;
347 struct componentname *cnp = ap->a_cnp;
348 struct vnode *dvp, *lvp, *ldvp;
349 int error, flags = cnp->cn_flags;
350
351 dvp = ap->a_dvp;
352
353 if ((flags & ISLASTCN) && (dvp->v_mount->mnt_flag & MNT_RDONLY) &&
354 (cnp->cn_nameiop == DELETE || cnp->cn_nameiop == RENAME)) {
355 *ap->a_vpp = NULL;
356 return EROFS;
357 }
358
359 ldvp = LAYERVPTOLOWERVP(dvp);
360 ap->a_dvp = ldvp;
361 error = VCALL(ldvp, ap->a_desc->vdesc_offset, ap);
362 lvp = *ap->a_vpp;
363 *ap->a_vpp = NULL;
364
365 if (error == EJUSTRETURN && (flags & ISLASTCN) &&
366 (dvp->v_mount->mnt_flag & MNT_RDONLY) &&
367 (cnp->cn_nameiop == CREATE || cnp->cn_nameiop == RENAME))
368 error = EROFS;
369
370 /*
371 * We must do the same locking and unlocking at this layer as
372 * is done in the layers below us.
373 */
374 if (ldvp == lvp) {
375 /*
376 * Got the same object back, because we looked up ".",
377 * or ".." in the root node of a mount point.
378 * So we make another reference to dvp and return it.
379 */
380 vref(dvp);
381 *ap->a_vpp = dvp;
382 vrele(lvp);
383 } else if (lvp != NULL) {
384 /* Note: dvp and ldvp are both locked. */
385 error = layer_node_create(dvp->v_mount, lvp, ap->a_vpp);
386 if (error) {
387 vrele(lvp);
388 }
389 }
390 return error;
391}
392
393/*
394 * Setattr call. Disallow write attempts if the layer is mounted read-only.
395 */
396int
397layer_setattr(void *v)
398{
399 struct vop_setattr_args /* {
400 struct vnodeop_desc *a_desc;
401 struct vnode *a_vp;
402 struct vattr *a_vap;
403 kauth_cred_t a_cred;
404 struct lwp *a_l;
405 } */ *ap = v;
406 struct vnode *vp = ap->a_vp;
407 struct vattr *vap = ap->a_vap;
408
409 if ((vap->va_flags != VNOVAL || vap->va_uid != (uid_t)VNOVAL ||
410 vap->va_gid != (gid_t)VNOVAL || vap->va_atime.tv_sec != VNOVAL ||
411 vap->va_mtime.tv_sec != VNOVAL || vap->va_mode != (mode_t)VNOVAL) &&
412 (vp->v_mount->mnt_flag & MNT_RDONLY))
413 return EROFS;
414 if (vap->va_size != VNOVAL) {
415 switch (vp->v_type) {
416 case VDIR:
417 return EISDIR;
418 case VCHR:
419 case VBLK:
420 case VSOCK:
421 case VFIFO:
422 return 0;
423 case VREG:
424 case VLNK:
425 default:
426 /*
427 * Disallow write attempts if the filesystem is
428 * mounted read-only.
429 */
430 if (vp->v_mount->mnt_flag & MNT_RDONLY)
431 return EROFS;
432 }
433 }
434 return LAYERFS_DO_BYPASS(vp, ap);
435}
436
437/*
438 * We handle getattr only to change the fsid.
439 */
440int
441layer_getattr(void *v)
442{
443 struct vop_getattr_args /* {
444 struct vnode *a_vp;
445 struct vattr *a_vap;
446 kauth_cred_t a_cred;
447 struct lwp *a_l;
448 } */ *ap = v;
449 struct vnode *vp = ap->a_vp;
450 int error;
451
452 error = LAYERFS_DO_BYPASS(vp, ap);
453 if (error) {
454 return error;
455 }
456 /* Requires that arguments be restored. */
457 ap->a_vap->va_fsid = vp->v_mount->mnt_stat.f_fsidx.__fsid_val[0];
458 return 0;
459}
460
461int
462layer_access(void *v)
463{
464 struct vop_access_args /* {
465 struct vnode *a_vp;
466 int a_mode;
467 kauth_cred_t a_cred;
468 struct lwp *a_l;
469 } */ *ap = v;
470 struct vnode *vp = ap->a_vp;
471 mode_t mode = ap->a_mode;
472
473 /*
474 * Disallow write attempts on read-only layers;
475 * unless the file is a socket, fifo, or a block or
476 * character device resident on the file system.
477 */
478 if (mode & VWRITE) {
479 switch (vp->v_type) {
480 case VDIR:
481 case VLNK:
482 case VREG:
483 if (vp->v_mount->mnt_flag & MNT_RDONLY)
484 return EROFS;
485 break;
486 default:
487 break;
488 }
489 }
490 return LAYERFS_DO_BYPASS(vp, ap);
491}
492
493/*
494 * We must handle open to be able to catch MNT_NODEV and friends.
495 */
496int
497layer_open(void *v)
498{
499 struct vop_open_args /* {
500 const struct vnodeop_desc *a_desc;
501 struct vnode *a_vp;
502 int a_mode;
503 kauth_cred_t a_cred;
504 } */ *ap = v;
505 struct vnode *vp = ap->a_vp;
506 enum vtype lower_type = LAYERVPTOLOWERVP(vp)->v_type;
507
508 if (((lower_type == VBLK) || (lower_type == VCHR)) &&
509 (vp->v_mount->mnt_flag & MNT_NODEV))
510 return ENXIO;
511
512 return LAYERFS_DO_BYPASS(vp, ap);
513}
514
515/*
516 * If vinvalbuf is calling us, it's a "shallow fsync" -- don't bother
517 * syncing the underlying vnodes, since they'll be fsync'ed when
518 * reclaimed; otherwise, pass it through to the underlying layer.
519 *
520 * XXX Do we still need to worry about shallow fsync?
521 */
522int
523layer_fsync(void *v)
524{
525 struct vop_fsync_args /* {
526 struct vnode *a_vp;
527 kauth_cred_t a_cred;
528 int a_flags;
529 off_t offlo;
530 off_t offhi;
531 struct lwp *a_l;
532 } */ *ap = v;
533 int error;
534
535 if (ap->a_flags & FSYNC_RECLAIM) {
536 return 0;
537 }
538 if (ap->a_vp->v_type == VBLK || ap->a_vp->v_type == VCHR) {
539 error = spec_fsync(v);
540 if (error)
541 return error;
542 }
543 return LAYERFS_DO_BYPASS(ap->a_vp, ap);
544}
545
546int
547layer_inactive(void *v)
548{
549 struct vop_inactive_args /* {
550 struct vnode *a_vp;
551 bool *a_recycle;
552 } */ *ap = v;
553 struct vnode *vp = ap->a_vp;
554
555 /*
556 * If we did a remove, don't cache the node.
557 */
558 *ap->a_recycle = ((VTOLAYER(vp)->layer_flags & LAYERFS_REMOVED) != 0);
559
560 /*
561 * Do nothing (and _don't_ bypass).
562 * Wait to vrele lowervp until reclaim,
563 * so that until then our layer_node is in the
564 * cache and reusable.
565 *
566 * NEEDSWORK: Someday, consider inactive'ing
567 * the lowervp and then trying to reactivate it
568 * with capabilities (v_id)
569 * like they do in the name lookup cache code.
570 * That's too much work for now.
571 */
572 VOP_UNLOCK(vp);
573 return 0;
574}
575
576int
577layer_remove(void *v)
578{
579 struct vop_remove_args /* {
580 struct vonde *a_dvp;
581 struct vnode *a_vp;
582 struct componentname *a_cnp;
583 } */ *ap = v;
584 struct vnode *vp = ap->a_vp;
585 int error;
586
587 vref(vp);
588 error = LAYERFS_DO_BYPASS(vp, ap);
589 if (error == 0) {
590 VTOLAYER(vp)->layer_flags |= LAYERFS_REMOVED;
591 }
592 vrele(vp);
593
594 return error;
595}
596
597int
598layer_rename(void *v)
599{
600 struct vop_rename_args /* {
601 struct vnode *a_fdvp;
602 struct vnode *a_fvp;
603 struct componentname *a_fcnp;
604 struct vnode *a_tdvp;
605 struct vnode *a_tvp;
606 struct componentname *a_tcnp;
607 } */ *ap = v;
608 struct vnode *fdvp = ap->a_fdvp, *tvp;
609 int error;
610
611 tvp = ap->a_tvp;
612 if (tvp) {
613 if (tvp->v_mount != fdvp->v_mount)
614 tvp = NULL;
615 else
616 vref(tvp);
617 }
618 error = LAYERFS_DO_BYPASS(fdvp, ap);
619 if (tvp) {
620 if (error == 0)
621 VTOLAYER(tvp)->layer_flags |= LAYERFS_REMOVED;
622 vrele(tvp);
623 }
624 return error;
625}
626
627int
628layer_rmdir(void *v)
629{
630 struct vop_rmdir_args /* {
631 struct vnode *a_dvp;
632 struct vnode *a_vp;
633 struct componentname *a_cnp;
634 } */ *ap = v;
635 int error;
636 struct vnode *vp = ap->a_vp;
637
638 vref(vp);
639 error = LAYERFS_DO_BYPASS(vp, ap);
640 if (error == 0) {
641 VTOLAYER(vp)->layer_flags |= LAYERFS_REMOVED;
642 }
643 vrele(vp);
644
645 return error;
646}
647
648int
649layer_revoke(void *v)
650{
651 struct vop_revoke_args /* {
652 struct vnode *a_vp;
653 int a_flags;
654 } */ *ap = v;
655 struct vnode *vp = ap->a_vp;
656 struct vnode *lvp = LAYERVPTOLOWERVP(vp);
657 int error;
658
659 /*
660 * We will most likely end up in vclean which uses the v_usecount
661 * to determine if a vnode is active. Take an extra reference on
662 * the lower vnode so it will always close and inactivate.
663 */
664 vref(lvp);
665 error = LAYERFS_DO_BYPASS(vp, ap);
666 vrele(lvp);
667
668 return error;
669}
670
671int
672layer_reclaim(void *v)
673{
674 struct vop_reclaim_args /* {
675 struct vnode *a_vp;
676 struct lwp *a_l;
677 } */ *ap = v;
678 struct vnode *vp = ap->a_vp;
679 struct layer_mount *lmp = MOUNTTOLAYERMOUNT(vp->v_mount);
680 struct layer_node *xp = VTOLAYER(vp);
681 struct vnode *lowervp = xp->layer_lowervp;
682
683 /*
684 * Note: in vop_reclaim, the node's struct lock has been
685 * decomissioned, so we have to be careful about calling
686 * VOP's on ourself. We must be careful as VXLOCK is set.
687 */
688 if (vp == lmp->layerm_rootvp) {
689 /*
690 * Oops! We no longer have a root node. Most likely reason is
691 * that someone forcably unmunted the underlying fs.
692 *
693 * Now getting the root vnode will fail. We're dead. :-(
694 */
695 lmp->layerm_rootvp = NULL;
696 }
697 /* After this assignment, this node will not be re-used. */
698 xp->layer_lowervp = NULL;
699 kmem_free(vp->v_data, lmp->layerm_size);
700 vp->v_data = NULL;
701 vrele(lowervp);
702
703 return 0;
704}
705
706int
707layer_lock(void *v)
708{
709 struct vop_lock_args /* {
710 struct vnode *a_vp;
711 int a_flags;
712 } */ *ap = v;
713 struct vnode *vp = ap->a_vp;
714 struct vnode *lowervp = LAYERVPTOLOWERVP(vp);
715 int flags = ap->a_flags;
716 int error;
717
718 if (ISSET(flags, LK_NOWAIT)) {
719 error = VOP_LOCK(lowervp, flags);
720 if (error)
721 return error;
722 if (mutex_tryenter(vp->v_interlock)) {
723 error = vdead_check(vp, VDEAD_NOWAIT);
724 mutex_exit(vp->v_interlock);
725 } else
726 error = EBUSY;
727 if (error)
728 VOP_UNLOCK(lowervp);
729 return error;
730 }
731
732 error = VOP_LOCK(lowervp, flags);
733 if (error)
734 return error;
735
736 mutex_enter(vp->v_interlock);
737 error = vdead_check(vp, VDEAD_NOWAIT);
738 if (error) {
739 VOP_UNLOCK(lowervp);
740 error = vdead_check(vp, 0);
741 KASSERT(error == ENOENT);
742 }
743 mutex_exit(vp->v_interlock);
744
745 return error;
746}
747
748/*
749 * We just feed the returned vnode up to the caller - there's no need
750 * to build a layer node on top of the node on which we're going to do
751 * i/o. :-)
752 */
753int
754layer_bmap(void *v)
755{
756 struct vop_bmap_args /* {
757 struct vnode *a_vp;
758 daddr_t a_bn;
759 struct vnode **a_vpp;
760 daddr_t *a_bnp;
761 int *a_runp;
762 } */ *ap = v;
763 struct vnode *vp;
764
765 vp = LAYERVPTOLOWERVP(ap->a_vp);
766 ap->a_vp = vp;
767
768 return VCALL(vp, ap->a_desc->vdesc_offset, ap);
769}
770
771int
772layer_print(void *v)
773{
774 struct vop_print_args /* {
775 struct vnode *a_vp;
776 } */ *ap = v;
777 struct vnode *vp = ap->a_vp;
778 printf ("\ttag VT_LAYERFS, vp=%p, lowervp=%p\n", vp, LAYERVPTOLOWERVP(vp));
779 return 0;
780}
781
782int
783layer_getpages(void *v)
784{
785 struct vop_getpages_args /* {
786 struct vnode *a_vp;
787 voff_t a_offset;
788 struct vm_page **a_m;
789 int *a_count;
790 int a_centeridx;
791 vm_prot_t a_access_type;
792 int a_advice;
793 int a_flags;
794 } */ *ap = v;
795 struct vnode *vp = ap->a_vp;
796
797 KASSERT(mutex_owned(vp->v_interlock));
798
799 if (ap->a_flags & PGO_LOCKED) {
800 return EBUSY;
801 }
802 ap->a_vp = LAYERVPTOLOWERVP(vp);
803 KASSERT(vp->v_interlock == ap->a_vp->v_interlock);
804
805 /* Just pass the request on to the underlying layer. */
806 return VCALL(ap->a_vp, VOFFSET(vop_getpages), ap);
807}
808
809int
810layer_putpages(void *v)
811{
812 struct vop_putpages_args /* {
813 struct vnode *a_vp;
814 voff_t a_offlo;
815 voff_t a_offhi;
816 int a_flags;
817 } */ *ap = v;
818 struct vnode *vp = ap->a_vp;
819
820 KASSERT(mutex_owned(vp->v_interlock));
821
822 ap->a_vp = LAYERVPTOLOWERVP(vp);
823 KASSERT(vp->v_interlock == ap->a_vp->v_interlock);
824
825 if (ap->a_flags & PGO_RECLAIM) {
826 mutex_exit(vp->v_interlock);
827 return 0;
828 }
829
830 /* Just pass the request on to the underlying layer. */
831 return VCALL(ap->a_vp, VOFFSET(vop_putpages), ap);
832}
833