1 /*
2 * CDDL HEADER START
3 *
4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License (the "License").
6 * You may not use this file except in compliance with the License.
7 *
8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9 * or http://www.opensolaris.org/os/licensing.
10 * See the License for the specific language governing permissions
11 * and limitations under the License.
12 *
13 * When distributing Covered Code, include this CDDL HEADER in each
14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15 * If applicable, add the following below this CDDL HEADER, with the
16 * fields enclosed by brackets "[]" replaced with your own identifying
17 * information: Portions Copyright [yyyy] [name of copyright owner]
18 *
19 * CDDL HEADER END
20 */
21
22 /*
23 * Copyright 2014 Nexenta Systems, Inc. All rights reserved.
24 * Copyright (c) 2003, 2010, Oracle and/or its affiliates. All rights reserved.
25 */
26
27 #include <sys/systm.h>
28
29 #include <nfs/nfs.h>
30 #include <nfs/export.h>
31 #include <sys/cmn_err.h>
32 #include <sys/avl.h>
33
34 #define PSEUDOFS_SUFFIX " (pseudo)"
35
36 /*
37 * A version of VOP_FID that deals with a remote VOP_FID for nfs.
38 * If vp is an nfs node, nfs4_fid() returns EREMOTE, nfs3_fid() and nfs_fid()
39 * returns the filehandle of vp as its fid. When nfs uses fid to set the
40 * exportinfo filehandle template, a remote nfs filehandle would be too big for
41 * the fid of the exported directory. This routine remaps the value of the
42 * attribute va_nodeid of vp to be the fid of vp, so that the fid can fit.
43 *
44 * We need this fid mainly for setting up NFSv4 server namespace where an
45 * nfs filesystem is also part of it. Thus, need to be able to setup a pseudo
46 * exportinfo for an nfs node.
47 *
48 * e.g. mount a filesystem on top of a nfs dir, and then share the new mount
49 * (like exporting a local disk from a "diskless" client)
50 */
51 int
52 vop_fid_pseudo(vnode_t *vp, fid_t *fidp)
53 {
54 struct vattr va;
55 int error;
56
57 error = VOP_FID(vp, fidp, NULL);
58
59 /*
60 * XXX nfs4_fid() does nothing and returns EREMOTE.
61 * XXX nfs3_fid()/nfs_fid() returns nfs filehandle as its fid
62 * which has a bigger length than local fid.
63 * NFS_FH4MAXDATA is the size of
64 * fhandle4_t.fh_xdata[NFS_FH4MAXDATA].
65 *
66 * Note: nfs[2,3,4]_fid() only gets called for diskless clients.
67 */
68 if (error == EREMOTE ||
69 (error == 0 && fidp->fid_len > NFS_FH4MAXDATA)) {
70
71 va.va_mask = AT_NODEID;
72 error = VOP_GETATTR(vp, &va, 0, CRED(), NULL);
73 if (error)
74 return (error);
75
76 fidp->fid_len = sizeof (va.va_nodeid);
77 bcopy(&va.va_nodeid, fidp->fid_data, fidp->fid_len);
78 return (0);
79 }
80
81 return (error);
82 }
83
84 /*
85 * Get an nfsv4 vnode of the given fid from the visible list of an
86 * nfs filesystem or get the exi_vp if it is the root node.
87 */
88 int
89 nfs4_vget_pseudo(struct exportinfo *exi, vnode_t **vpp, fid_t *fidp)
90 {
91 fid_t exp_fid;
92 struct exp_visible *visp;
93 int error;
94
95 /* check if the given fid is in the visible list */
96
97 for (visp = exi->exi_visible; visp; visp = visp->vis_next) {
98 if (EQFID(fidp, &visp->vis_fid)) {
99 VN_HOLD(visp->vis_vp);
100 *vpp = visp->vis_vp;
101 return (0);
102 }
103 }
104
105 /* check if the given fid is the same as the exported node */
106
107 bzero(&exp_fid, sizeof (exp_fid));
108 exp_fid.fid_len = MAXFIDSZ;
109 error = vop_fid_pseudo(exi->exi_vp, &exp_fid);
110 if (error)
111 return (error);
112
113 if (EQFID(fidp, &exp_fid)) {
114 VN_HOLD(exi->exi_vp);
115 *vpp = exi->exi_vp;
116 return (0);
117 }
118
119 return (ENOENT);
120 }
121
122 /*
123 * Create a pseudo export entry
124 *
125 * This is an export entry that's created as the
126 * side-effect of a "real" export. As a part of
127 * a real export, the pathname to the export is
128 * checked to see if all the directory components
129 * are accessible via an NFSv4 client, i.e. are
130 * exported. If treeclimb_export() finds an unexported
131 * mountpoint along the path, then it calls this
132 * function to export it.
133 *
134 * This pseudo export differs from a real export in that
135 * it only allows read-only access. A "visible" list of
136 * directories is added to filter lookup and readdir results
137 * to only contain dirnames which lead to descendant shares.
138 *
139 * A visible list has a per-file-system scope. Any exportinfo
140 * struct (real or pseudo) can have a visible list as long as
141 * a) its export root is VROOT
142 * b) a descendant of the export root is shared
143 */
144 struct exportinfo *
145 pseudo_exportfs(vnode_t *vp, fid_t *fid, struct exp_visible *vis_head,
146 struct exportdata *exdata)
147 {
148 struct exportinfo *exi;
149 struct exportdata *kex;
150 fsid_t fsid;
151 int vpathlen;
152 int i;
153
154 ASSERT(RW_WRITE_HELD(&exported_lock));
155
156 fsid = vp->v_vfsp->vfs_fsid;
157 exi = kmem_zalloc(sizeof (*exi), KM_SLEEP);
158 exi->exi_fsid = fsid;
159 exi->exi_fid = *fid;
160 exi->exi_vp = vp;
161 VN_HOLD(exi->exi_vp);
162 exi->exi_visible = vis_head;
163 exi->exi_count = 1;
164 exi->exi_volatile_dev = (vfssw[vp->v_vfsp->vfs_fstype].vsw_flag &
165 VSW_VOLATILEDEV) ? 1 : 0;
166 mutex_init(&exi->exi_lock, NULL, MUTEX_DEFAULT, NULL);
167
168 /*
169 * Build up the template fhandle
170 */
171 exi->exi_fh.fh_fsid = fsid;
172 ASSERT(exi->exi_fid.fid_len <= sizeof (exi->exi_fh.fh_xdata));
173 exi->exi_fh.fh_xlen = exi->exi_fid.fid_len;
174 bcopy(exi->exi_fid.fid_data, exi->exi_fh.fh_xdata,
175 exi->exi_fid.fid_len);
176 exi->exi_fh.fh_len = sizeof (exi->exi_fh.fh_data);
177
178 kex = &exi->exi_export;
179 kex->ex_flags = EX_PSEUDO;
180
181 vpathlen = vp->v_path ? strlen(vp->v_path) : 0;
182 kex->ex_pathlen = vpathlen + strlen(PSEUDOFS_SUFFIX);
183 kex->ex_path = kmem_alloc(kex->ex_pathlen + 1, KM_SLEEP);
184
185 if (vpathlen)
186 (void) strcpy(kex->ex_path, vp->v_path);
187 (void) strcpy(kex->ex_path + vpathlen, PSEUDOFS_SUFFIX);
188
189 /* Transfer the secinfo data from exdata to this new pseudo node */
190 if (exdata)
191 srv_secinfo_exp2pseu(&exi->exi_export, exdata);
192
193 /*
194 * Initialize auth cache and auth cache lock
195 */
196 for (i = 0; i < AUTH_TABLESIZE; i++) {
197 exi->exi_cache[i] = kmem_alloc(sizeof (avl_tree_t), KM_SLEEP);
198 avl_create(exi->exi_cache[i], nfsauth_cache_clnt_compar,
199 sizeof (struct auth_cache_clnt),
200 offsetof(struct auth_cache_clnt, authc_link));
201 }
202 rw_init(&exi->exi_cache_lock, NULL, RW_DEFAULT, NULL);
203
204 /*
205 * Insert the new entry at the front of the export list
206 */
207 export_link(exi);
208
209 return (exi);
210 }
211
212 /*
213 * Free a list of visible directories
214 */
215 void
216 free_visible(struct exp_visible *head)
217 {
218 struct exp_visible *visp, *next;
219
220 for (visp = head; visp; visp = next) {
221 if (visp->vis_vp != NULL)
222 VN_RELE(visp->vis_vp);
223
224 next = visp->vis_next;
225 srv_secinfo_list_free(visp->vis_secinfo, visp->vis_seccnt);
226 kmem_free(visp, sizeof (*visp));
227 }
228 }
229
230 /*
231 * Connects newchild (or subtree with newchild in head)
232 * to the parent node. We always add it to the beginning
233 * of sibling list.
234 */
235 static void
236 tree_add_child(treenode_t *parent, treenode_t *newchild)
237 {
238 newchild->tree_parent = parent;
239 newchild->tree_sibling = parent->tree_child_first;
240 parent->tree_child_first = newchild;
241 }
242
243 /* Look up among direct children a node with the exact tree_vis pointer */
244 static treenode_t *
245 tree_find_child_by_vis(treenode_t *t, exp_visible_t *vis)
246 {
247 for (t = t->tree_child_first; t; t = t->tree_sibling)
248 if (t->tree_vis == vis)
249 return (t);
250 return (NULL);
251 }
252
253 /*
254 * Add new node to the head of subtree pointed by 'n'. n can be NULL.
255 * Interconnects the new treenode with exp_visible and exportinfo
256 * if needed.
257 */
258 static treenode_t *
259 tree_prepend_node(treenode_t *n, exp_visible_t *v, exportinfo_t *e)
260 {
261 treenode_t *tnode = kmem_zalloc(sizeof (*tnode), KM_SLEEP);
262
263 if (n) {
264 tnode->tree_child_first = n;
265 n->tree_parent = tnode;
266 }
267 if (v) {
268 tnode->tree_vis = v;
269 }
270 if (e) {
271 tnode->tree_exi = e;
272 e->exi_tree = tnode;
273 }
274 return (tnode);
275 }
276
277 /*
278 * Removes node from the tree and frees the treenode struct.
279 * Does not free structures pointed by tree_exi and tree_vis,
280 * they should be already freed.
281 */
282 static void
283 tree_remove_node(treenode_t *node)
284 {
285 treenode_t *parent = node->tree_parent;
286 treenode_t *s; /* s for sibling */
287
288 if (parent == NULL) {
289 kmem_free(node, sizeof (*node));
290 ns_root = NULL;
291 return;
292 }
293 /* This node is first child */
294 if (parent->tree_child_first == node) {
295 parent->tree_child_first = node->tree_sibling;
296 /* This node is not first child */
297 } else {
298 s = parent->tree_child_first;
299 while (s->tree_sibling != node)
300 s = s->tree_sibling;
301 s->tree_sibling = s->tree_sibling->tree_sibling;
302 }
303 kmem_free(node, sizeof (*node));
304 }
305
306 /*
307 * When we export a new directory we need to add a new
308 * path segment through the pseudofs to reach the new
309 * directory. This new path is reflected in a list of
310 * directories added to the "visible" list.
311 *
312 * Here there are two lists of visible fids: one hanging off the
313 * pseudo exportinfo, and the one we want to add. It's possible
314 * that the two lists share a common path segment
315 * and have some common directories. We need to combine
316 * the lists so there's no duplicate entries. Where a common
317 * path component is found, the vis_count field is bumped.
318 *
319 * This example shows that the treenode chain (tree_head) and
320 * exp_visible chain (vis_head) can differ in length. The latter
321 * can be shorter. The outer loop must loop over the vis_head chain.
322 *
323 * share /x/a
324 * mount -F ufs /dev/dsk/... /x/y
325 * mkdir -p /x/y/a/b
326 * share /x/y/a/b
327 *
328 * When more_visible() is called during the second share,
329 * the existing namespace is following:
330 * exp_visible_t
331 * treenode_t exportinfo_t v0 v1
332 * ns_root+---+ +------------+ +---+ +---+
333 * t0| / |........| E0 pseudo |->| x |->| a |
334 * +---+ +------------+ +---+ +---+
335 * | / /
336 * +---+ / /
337 * t1| x |------------------------ /
338 * +---+ /
339 * | /
340 * +---+ /
341 * t2| a |-------------------------
342 * +---+........+------------+
343 * | E1 real |
344 * +------------+
345 *
346 * This is being added:
347 *
348 * tree_head vis_head
349 * +---+ +---+
350 * t3| x |->| x |v2
351 * +---+ +---+
352 * | |
353 * +---+ +---+ v4 v5
354 * t4| y |->| y |v3 +------------+ +---+ +---+
355 * +---+\ +---+ | E2 pseudo |->| a |->| b |
356 * | \....... >+------------+ +---+ +---+
357 * +---+ / /
358 * t5| a |--------------------------- /
359 * +---+ /
360 * | /
361 * +---+-------------------------------
362 * t6| b | +------------+
363 * +---+..........>| E3 real |
364 * +------------+
365 *
366 * more_visible() will:
367 * - kmem_free() t3 and v2
368 * - add t4, t5, t6 as a child of t1 (t4 will become sibling of t2)
369 * - add v3 to the end of E0->exi_visible
370 *
371 * Note that v4 and v5 were already processed in pseudo_exportfs() and
372 * added to E2. The outer loop of more_visible() will loop only over v2
373 * and v3. The inner loop of more_visible() always loops over v0 and v1.
374 *
375 * Illustration for this scenario:
376 *
377 * mkdir -p /v/a/b/c
378 * share /v/a/b/c
379 * mkdir /v/a/b/c1
380 * mkdir -p /v/a1
381 * mv /v/a/b /v/a1
382 * share /v/a1/b/c1
383 *
384 * EXISTING
385 * treenode
386 * namespace: +-----------+ visibles
387 * |exportinfo |-->v->a->b->c
388 * connect_point->+---+--->+-----------+
389 * | / |T0
390 * +---+
391 * | NEW treenode chain:
392 * child->+---+
393 * | v |T1 +---+<-curr
394 * +---+ N1| v |
395 * | +---+
396 * +---+ |
397 * | a |T2 +---+<-tree_head
398 * +---+ N2| a1|
399 * | +---+
400 * +---+ |
401 * | b |T3 +---+
402 * +---+ N3| b |
403 * | +---+
404 * +---+ |
405 * | c |T4 +---+
406 * +---+ N4| c1|
407 * +---+
408 *
409 * The picture above illustrates the position of following pointers after line
410 * 'child = tree_find_child_by_vis(connect_point, curr->tree_vis);'
411 * was executed for the first time in the outer 'for' loop:
412 *
413 * connect_point..parent treenode in the EXISTING namespace to which the 'curr'
414 * should be connected. If 'connect_point' already has a child
415 * with the same value of tree_vis as the curr->tree_vis is,
416 * the 'curr' will not be added, but kmem_free()d.
417 * child..........the result of tree_find_child_by_vis()
418 * curr...........currently processed treenode from the NEW treenode chain
419 * tree_head......current head of the NEW treenode chain, in this case it was
420 * already moved down to its child - preparation for another loop
421 *
422 * What will happen to NEW treenodes N1, N2, N3, N4 in more_visible() later:
423 *
424 * N1: is merged - i.e. N1 is kmem_free()d. T0 has a child T1 with the same
425 * tree_vis as N1
426 * N2: is added as a new child of T1
427 * Note: not just N2, but the whole chain N2->N3->N4 is added
428 * N3: not processed separately (it was added together with N2)
429 * Even that N3 and T3 have same tree_vis, they are NOT merged, but will
430 * become duplicates.
431 * N4: not processed separately
432 */
433 static void
434 more_visible(struct exportinfo *exi, treenode_t *tree_head)
435 {
436 struct exp_visible *vp1, *vp2, *vis_head, *tail, *next;
437 int found;
438 treenode_t *child, *curr, *connect_point;
439
440 vis_head = tree_head->tree_vis;
441 connect_point = exi->exi_tree;
442
443 /*
444 * If exportinfo doesn't already have a visible
445 * list just assign the entire supplied list.
446 */
447 if (exi->exi_visible == NULL) {
448 tree_add_child(exi->exi_tree, tree_head);
449 exi->exi_visible = vis_head;
450 return;
451 }
452
453 /* The outer loop traverses the supplied list. */
454 for (vp1 = vis_head; vp1; vp1 = next) {
455 found = 0;
456 next = vp1->vis_next;
457
458 /* The inner loop searches the exportinfo visible list. */
459 for (vp2 = exi->exi_visible; vp2; vp2 = vp2->vis_next) {
460 tail = vp2;
461 if (EQFID(&vp1->vis_fid, &vp2->vis_fid)) {
462 found = 1;
463 vp2->vis_count++;
464 VN_RELE(vp1->vis_vp);
465 /* Transfer vis_exported from vp1 to vp2. */
466 if (vp1->vis_exported && !vp2->vis_exported)
467 vp2->vis_exported = 1;
468 kmem_free(vp1, sizeof (*vp1));
469 tree_head->tree_vis = vp2;
470 break;
471 }
472 }
473
474 /* If not found - add to the end of the list */
475 if (! found) {
476 tail->vis_next = vp1;
477 vp1->vis_next = NULL;
478 }
479
480 curr = tree_head;
481 tree_head = tree_head->tree_child_first;
482
483 if (! connect_point) /* No longer merging */
484 continue;
485 /*
486 * The inner loop could set curr->tree_vis to the EXISTING
487 * exp_visible vp2, so we can search among the children of
488 * connect_point for the curr->tree_vis. No need for EQFID.
489 */
490 child = tree_find_child_by_vis(connect_point, curr->tree_vis);
491
492 /*
493 * Merging cannot be done if a valid child->tree_exi would
494 * be overwritten by a new curr->tree_exi.
495 */
496 if (child &&
497 (child->tree_exi == NULL || curr->tree_exi == NULL)) {
498 if (curr->tree_exi) { /* Transfer the exportinfo */
499 child->tree_exi = curr->tree_exi;
500 child->tree_exi->exi_tree = child;
501 }
502 kmem_free(curr, sizeof (treenode_t));
503 connect_point = child;
504 } else { /* Branching */
505 tree_add_child(connect_point, curr);
506 connect_point = NULL;
507 }
508 }
509 }
510
511 /*
512 * Remove one visible entry from the pseudo exportfs.
513 *
514 * When we unexport a directory, we have to remove path
515 * components from the visible list in the pseudo exportfs
516 * entry. The supplied visible contains one fid of one path
517 * component. The visible list of the export
518 * is checked against provided visible, matching fid has its
519 * reference count decremented. If a reference count drops to
520 * zero, then it means no paths now use this directory, so its
521 * fid can be removed from the visible list.
522 *
523 * When the last path is removed, the visible list will be null.
524 */
525 static void
526 less_visible(struct exportinfo *exi, struct exp_visible *vp1)
527 {
528 struct exp_visible *vp2;
529 struct exp_visible *prev, *next;
530
531 for (vp2 = exi->exi_visible, prev = NULL; vp2; vp2 = next) {
532
533 next = vp2->vis_next;
534
535 if (vp1 == vp2) {
536 /*
537 * Decrement the ref count.
538 * Remove the entry if it's zero.
539 */
540 if (--vp2->vis_count <= 0) {
541 if (prev == NULL)
542 exi->exi_visible = next;
543 else
544 prev->vis_next = next;
545 VN_RELE(vp2->vis_vp);
546 srv_secinfo_list_free(vp2->vis_secinfo,
547 vp2->vis_seccnt);
548 kmem_free(vp2, sizeof (*vp1));
549 }
550 break;
551 }
552 prev = vp2;
553 }
554 }
555
556 /*
557 * This function checks the path to a new export to
558 * check whether all the pathname components are
559 * exported. It works by climbing the file tree one
560 * component at a time via "..", crossing mountpoints
561 * if necessary until an export entry is found, or the
562 * system root is reached.
563 *
564 * If an unexported mountpoint is found, then
565 * a new pseudo export is added and the pathname from
566 * the mountpoint down to the export is added to the
567 * visible list for the new pseudo export. If an existing
568 * pseudo export is found, then the pathname is added
569 * to its visible list.
570 *
571 * Note that there's some tests for exportdir.
572 * The exportinfo entry that's passed as a parameter
573 * is that of the real export and exportdir is set
574 * for this case.
575 *
576 * Here is an example of a possible setup:
577 *
578 * () - a new fs; fs mount point
579 * EXPORT - a real exported node
580 * PSEUDO - a pseudo node
581 * vis - visible list
582 * f# - security flavor#
583 * (f#) - security flavor# propagated from its descendents
584 * "" - covered vnode
585 *
586 *
587 * /
588 * |
589 * (a) PSEUDO (f1,f2)
590 * | vis: b,b,"c","n"
591 * |
592 * b
593 * ---------|------------------
594 * | |
595 * (c) EXPORT,f1(f2) (n) PSEUDO (f1,f2)
596 * | vis: "e","d" | vis: m,m,,p,q,"o"
597 * | |
598 * ------------------ -------------------
599 * | | | | |
600 * (d) (e) f m EXPORT,f1(f2) p
601 * EXPORT EXPORT | |
602 * f1 f2 | |
603 * | | |
604 * j (o) EXPORT,f2 q EXPORT f2
605 *
606 */
607 int
608 treeclimb_export(struct exportinfo *exip)
609 {
610 vnode_t *dvp, *vp;
611 fid_t fid;
612 int error;
613 int exportdir;
614 struct exportinfo *exi = NULL;
615 struct exportinfo *new_exi = exip;
616 struct exp_visible *visp;
617 struct exp_visible *vis_head = NULL;
618 struct vattr va;
619 treenode_t *tree_head = NULL;
620
621 ASSERT(RW_WRITE_HELD(&exported_lock));
622
623 vp = exip->exi_vp;
624 VN_HOLD(vp);
625 exportdir = 1;
626
627 for (;;) {
628
629 bzero(&fid, sizeof (fid));
630 fid.fid_len = MAXFIDSZ;
631 error = vop_fid_pseudo(vp, &fid);
632 if (error)
633 break;
634
635 if (! exportdir) {
636 /*
637 * Check if this exportroot is a VROOT dir. If so,
638 * then attach the pseudonodes. If not, then
639 * continue .. traversal until we hit a VROOT
640 * export (pseudo or real).
641 */
642 exi = checkexport_nohold(&vp->v_vfsp->vfs_fsid, &fid,
643 vp);
644 if (exi != NULL && vp->v_flag & VROOT) {
645 /*
646 * Found an export info
647 *
648 * Extend the list of visible
649 * directories whether it's a pseudo
650 * or a real export.
651 */
652 more_visible(exi, tree_head);
653 break; /* and climb no further */
654 }
655 }
656
657 /*
658 * If at the root of the filesystem, need
659 * to traverse across the mountpoint
660 * and continue the climb on the mounted-on
661 * filesystem.
662 */
663 if (vp->v_flag & VROOT) {
664
665 if (! exportdir) {
666 /*
667 * Found the root directory of a filesystem
668 * that isn't exported. Need to export
669 * this as a pseudo export so that an NFS v4
670 * client can do lookups in it.
671 */
672 new_exi = pseudo_exportfs(vp, &fid, vis_head,
673 NULL);
674 vis_head = NULL;
675 }
676
677 if (VN_CMP(vp, rootdir)) {
678 /* at system root */
679 /*
680 * If sharing "/", new_exi is shared exportinfo
681 * (exip). Otherwise, new_exi is exportinfo
682 * created in pseudo_exportfs() above.
683 */
684 ns_root = tree_prepend_node(tree_head, 0,
685 new_exi);
686 break;
687 }
688
689 vp = untraverse(vp);
690 exportdir = 0;
691 continue;
692 }
693
694 /*
695 * Do a getattr to obtain the nodeid (inode num)
696 * for this vnode.
697 */
698 va.va_mask = AT_NODEID;
699 error = VOP_GETATTR(vp, &va, 0, CRED(), NULL);
700 if (error)
701 break;
702
703 /*
704 * Add this directory fid to visible list
705 */
706 visp = kmem_alloc(sizeof (*visp), KM_SLEEP);
707 VN_HOLD(vp);
708 visp->vis_vp = vp;
709 visp->vis_fid = fid; /* structure copy */
710 visp->vis_ino = va.va_nodeid;
711 visp->vis_count = 1;
712 visp->vis_exported = exportdir;
713 visp->vis_secinfo = NULL;
714 visp->vis_seccnt = 0;
715 visp->vis_next = vis_head;
716 vis_head = visp;
717
718
719 /*
720 * Will set treenode's pointer to exportinfo to
721 * 1. shared exportinfo (exip) - if first visit here
722 * 2. freshly allocated pseudo export (if any)
723 * 3. null otherwise
724 */
725 tree_head = tree_prepend_node(tree_head, visp, new_exi);
726 new_exi = NULL;
727
728 /*
729 * Now, do a ".." to find parent dir of vp.
730 */
731 error = VOP_LOOKUP(vp, "..", &dvp, NULL, 0, NULL, CRED(),
732 NULL, NULL, NULL);
733
734 if (error == ENOTDIR && exportdir) {
735 dvp = exip->exi_dvp;
736 ASSERT(dvp != NULL);
737 VN_HOLD(dvp);
738 error = 0;
739 }
740
741 if (error)
742 break;
743
744 exportdir = 0;
745 VN_RELE(vp);
746 vp = dvp;
747 }
748
749 VN_RELE(vp);
750
751 /*
752 * We can have set error due to error in:
753 * 1. vop_fid_pseudo()
754 * 2. VOP_GETATTR()
755 * 3. VOP_LOOKUP()
756 * We must free pseudo exportinfos, visibles and treenodes.
757 * Visibles are referenced from treenode_t::tree_vis and
758 * exportinfo_t::exi_visible. To avoid double freeing, only
759 * exi_visible pointer is used, via exi_rele(), for the clean-up.
760 */
761 if (error) {
762 /* Free unconnected visibles, if there are any. */
763 if (vis_head)
764 free_visible(vis_head);
765
766 /* Connect unconnected exportinfo, if there is any. */
767 if (new_exi && new_exi != exip)
768 tree_head = tree_prepend_node(tree_head, 0, new_exi);
769
770 while (tree_head) {
771 treenode_t *t2 = tree_head;
772 exportinfo_t *e = tree_head->tree_exi;
773 /* exip will be freed in exportfs() */
774 if (e && e != exip) {
775 export_unlink(e);
776 exi_rele(e);
777 }
778 tree_head = tree_head->tree_child_first;
779 kmem_free(t2, sizeof (*t2));
780 }
781 }
782
783 return (error);
784 }
785
786 /*
787 * Walk up the tree and:
788 * 1. release pseudo exportinfo if it has no child
789 * 2. release visible in parent's exportinfo
790 * 3. delete non-exported leaf nodes from tree
791 *
792 * Deleting of nodes will start only if the unshared
793 * node was a leaf node.
794 * Deleting of nodes will finish when we reach a node which
795 * has children or is a real export, then we might still need
796 * to continue releasing visibles, until we reach VROOT node.
797 */
798 void
799 treeclimb_unexport(struct exportinfo *exip)
800 {
801 treenode_t *tnode, *old_nd;
802
803 ASSERT(RW_WRITE_HELD(&exported_lock));
804
805 tnode = exip->exi_tree;
806 /*
807 * The unshared exportinfo was unlinked in unexport().
808 * Zeroing tree_exi ensures that we will skip it.
809 */
810 tnode->tree_exi = NULL;
811
812 if (tnode->tree_vis) /* system root has tree_vis == NULL */
813 tnode->tree_vis->vis_exported = 0;
814
815 while (tnode) {
816
817 /* Stop at VROOT node which is exported or has child */
818 if (TREE_ROOT(tnode) &&
819 (TREE_EXPORTED(tnode) || tnode->tree_child_first))
820 break;
821
822 /* Release pseudo export if it has no child */
823 if (TREE_ROOT(tnode) && !TREE_EXPORTED(tnode) &&
824 tnode->tree_child_first == 0) {
825 export_unlink(tnode->tree_exi);
826 exi_rele(tnode->tree_exi);
827 }
828
829 /* Release visible in parent's exportinfo */
830 if (tnode->tree_vis)
831 less_visible(vis2exi(tnode), tnode->tree_vis);
832
833 /* Continue with parent */
834 old_nd = tnode;
835 tnode = tnode->tree_parent;
836
837 /* Remove itself, if this is a leaf and non-exported node */
838 if (old_nd->tree_child_first == NULL && !TREE_EXPORTED(old_nd))
839 tree_remove_node(old_nd);
840 }
841 }
842
843 /*
844 * Traverse backward across mountpoint from the
845 * root vnode of a filesystem to its mounted-on
846 * vnode.
847 */
848 vnode_t *
849 untraverse(vnode_t *vp)
850 {
851 vnode_t *tvp, *nextvp;
852
853 tvp = vp;
854 for (;;) {
855 if (! (tvp->v_flag & VROOT))
856 break;
857
858 /* lock vfs to prevent unmount of this vfs */
859 vfs_lock_wait(tvp->v_vfsp);
860
861 if ((nextvp = tvp->v_vfsp->vfs_vnodecovered) == NULL) {
862 vfs_unlock(tvp->v_vfsp);
863 break;
864 }
865
866 /*
867 * Hold nextvp to prevent unmount. After unlock vfs and
868 * rele tvp, any number of overlays could be unmounted.
869 * Putting a hold on vfs_vnodecovered will only allow
870 * tvp's vfs to be unmounted. Of course if caller placed
871 * extra hold on vp before calling untraverse, the following
872 * hold would not be needed. Since prev actions of caller
873 * are unknown, we need to hold here just to be safe.
874 */
875 VN_HOLD(nextvp);
876 vfs_unlock(tvp->v_vfsp);
877 VN_RELE(tvp);
878 tvp = nextvp;
879 }
880
881 return (tvp);
882 }
883
884 /*
885 * Given an exportinfo, climb up to find the exportinfo for the VROOT
886 * of the filesystem.
887 *
888 * e.g. /
889 * |
890 * a (VROOT) pseudo-exportinfo
891 * |
892 * b
893 * |
894 * c #share /a/b/c
895 * |
896 * d
897 *
898 * where c is in the same filesystem as a.
899 * So, get_root_export(*exportinfo_for_c) returns exportinfo_for_a
900 *
901 * If d is shared, then c will be put into a's visible list.
902 * Note: visible list is per filesystem and is attached to the
903 * VROOT exportinfo.
904 */
905 struct exportinfo *
906 get_root_export(struct exportinfo *exip)
907 {
908 treenode_t *tnode = exip->exi_tree;
909 exportinfo_t *exi = NULL;
910
911 while (tnode) {
912 if (TREE_ROOT(tnode)) {
913 exi = tnode->tree_exi;
914 break;
915 }
916 tnode = tnode->tree_parent;
917 }
918 ASSERT(exi);
919 return (exi);
920 }
921
922 /*
923 * Return true if the supplied vnode has a sub-directory exported.
924 */
925 int
926 has_visible(struct exportinfo *exi, vnode_t *vp)
927 {
928 struct exp_visible *visp;
929 fid_t fid;
930 bool_t vp_is_exported;
931
932 vp_is_exported = VN_CMP(vp, exi->exi_vp);
933
934 /*
935 * An exported root vnode has a sub-dir shared if it has a visible list.
936 * i.e. if it does not have a visible list, then there is no node in
937 * this filesystem leads to any other shared node.
938 */
939 if (vp_is_exported && (vp->v_flag & VROOT))
940 return (exi->exi_visible ? 1 : 0);
941
942 /*
943 * Only the exportinfo of a fs root node may have a visible list.
944 * Either it is a pseudo root node, or a real exported root node.
945 */
946 exi = get_root_export(exi);
947
948 if (!exi->exi_visible)
949 return (0);
950
951 /* Get the fid of the vnode */
952 bzero(&fid, sizeof (fid));
953 fid.fid_len = MAXFIDSZ;
954 if (vop_fid_pseudo(vp, &fid) != 0) {
955 return (0);
956 }
957
958 /*
959 * See if vp is in the visible list of the root node exportinfo.
960 */
961 for (visp = exi->exi_visible; visp; visp = visp->vis_next) {
962 if (EQFID(&fid, &visp->vis_fid)) {
963 /*
964 * If vp is an exported non-root node with only 1 path
965 * count (for itself), it indicates no sub-dir shared
966 * using this vp as a path.
967 */
968 if (vp_is_exported && visp->vis_count < 2)
969 break;
970
971 return (1);
972 }
973 }
974
975 return (0);
976 }
977
978 /*
979 * Returns true if the supplied vnode is visible
980 * in this export. If vnode is visible, return
981 * vis_exported in expseudo.
982 */
983 int
984 nfs_visible(struct exportinfo *exi, vnode_t *vp, int *expseudo)
985 {
986 struct exp_visible *visp;
987 fid_t fid;
988
989 /*
990 * First check to see if vp is export root.
991 *
992 * A pseudo export root can never be exported
993 * (it would be a real export then); however,
994 * it is always visible. If a pseudo root object
995 * was exported by server admin, then the entire
996 * pseudo exportinfo (and all visible entries) would
997 * be destroyed. A pseudo exportinfo only exists
998 * to provide access to real (descendant) export(s).
999 *
1000 * Previously, rootdir was special cased here; however,
1001 * the export root special case handles the rootdir
1002 * case also.
1003 */
1004 if (VN_CMP(vp, exi->exi_vp)) {
1005 *expseudo = 0;
1006 return (1);
1007 }
1008
1009 /*
1010 * Only a PSEUDO node has a visible list or an exported VROOT
1011 * node may have a visible list.
1012 */
1013 if (! PSEUDO(exi))
1014 exi = get_root_export(exi);
1015
1016 /* Get the fid of the vnode */
1017
1018 bzero(&fid, sizeof (fid));
1019 fid.fid_len = MAXFIDSZ;
1020 if (vop_fid_pseudo(vp, &fid) != 0) {
1021 *expseudo = 0;
1022 return (0);
1023 }
1024
1025 /*
1026 * We can't trust VN_CMP() above because of LOFS.
1027 * Even though VOP_CMP will do the right thing for LOFS
1028 * objects, VN_CMP will short circuit out early when the
1029 * vnode ops ptrs are different. Just in case we're dealing
1030 * with LOFS, compare exi_fid/fsid here.
1031 *
1032 * expseudo is not set because this is not an export
1033 */
1034 if (EQFID(&exi->exi_fid, &fid) &&
1035 EQFSID(&exi->exi_fsid, &vp->v_vfsp->vfs_fsid)) {
1036 *expseudo = 0;
1037 return (1);
1038 }
1039
1040
1041 /* See if it matches any fid in the visible list */
1042
1043 for (visp = exi->exi_visible; visp; visp = visp->vis_next) {
1044 if (EQFID(&fid, &visp->vis_fid)) {
1045 *expseudo = visp->vis_exported;
1046 return (1);
1047 }
1048 }
1049
1050 *expseudo = 0;
1051
1052 return (0);
1053 }
1054
1055 /*
1056 * Returns true if the supplied vnode is the
1057 * directory of an export point.
1058 */
1059 int
1060 nfs_exported(struct exportinfo *exi, vnode_t *vp)
1061 {
1062 struct exp_visible *visp;
1063 fid_t fid;
1064
1065 /*
1066 * First check to see if vp is the export root
1067 * This check required for the case of lookup ..
1068 * where .. is a V_ROOT vnode and a pseudo exportroot.
1069 * Pseudo export root objects do not have an entry
1070 * in the visible list even though every V_ROOT
1071 * pseudonode is visible. It is safe to compare
1072 * vp here because pseudo_exportfs put a hold on
1073 * it when exi_vp was initialized.
1074 *
1075 * Note: VN_CMP() won't match for LOFS shares, but they're
1076 * handled below w/EQFID/EQFSID.
1077 */
1078 if (VN_CMP(vp, exi->exi_vp))
1079 return (1);
1080
1081 /* Get the fid of the vnode */
1082
1083 bzero(&fid, sizeof (fid));
1084 fid.fid_len = MAXFIDSZ;
1085 if (vop_fid_pseudo(vp, &fid) != 0)
1086 return (0);
1087
1088 if (EQFID(&fid, &exi->exi_fid) &&
1089 EQFSID(&vp->v_vfsp->vfs_fsid, &exi->exi_fsid)) {
1090 return (1);
1091 }
1092
1093 /* See if it matches any fid in the visible list */
1094
1095 for (visp = exi->exi_visible; visp; visp = visp->vis_next) {
1096 if (EQFID(&fid, &visp->vis_fid))
1097 return (visp->vis_exported);
1098 }
1099
1100 return (0);
1101 }
1102
1103 /*
1104 * Returns true if the supplied inode is visible
1105 * in this export. This function is used by
1106 * readdir which uses inode numbers from the
1107 * directory.
1108 *
1109 * NOTE: this code does not match inode number for ".",
1110 * but it isn't required because NFS4 server rddir
1111 * skips . and .. entries.
1112 */
1113 int
1114 nfs_visible_inode(struct exportinfo *exi, ino64_t ino, int *expseudo)
1115 {
1116 struct exp_visible *visp;
1117
1118 /*
1119 * Only a PSEUDO node has a visible list or an exported VROOT
1120 * node may have a visible list.
1121 */
1122 if (! PSEUDO(exi))
1123 exi = get_root_export(exi);
1124
1125 for (visp = exi->exi_visible; visp; visp = visp->vis_next)
1126 if ((u_longlong_t)ino == visp->vis_ino) {
1127 *expseudo = visp->vis_exported;
1128 return (1);
1129 }
1130
1131 *expseudo = 0;
1132 return (0);
1133 }