2 * Copyright (c) 2014 The FreeBSD Foundation
5 * This software was developed by Edward Tomasz Napierala under sponsorship
6 * from the FreeBSD Foundation.
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 #include <sys/cdefs.h>
32 __FBSDID("$FreeBSD$");
34 #include <sys/param.h>
35 #include <sys/kernel.h>
36 #include <sys/condvar.h>
37 #include <sys/dirent.h>
38 #include <sys/fcntl.h>
40 #include <sys/mount.h>
41 #include <sys/mutex.h>
42 #include <sys/namei.h>
43 #include <sys/signalvar.h>
45 #include <sys/systm.h>
46 #include <sys/taskqueue.h>
48 #include <sys/vnode.h>
49 #include <machine/atomic.h>
52 #include <fs/autofs/autofs.h>
54 static int autofs_trigger_vn(struct vnode *vp, const char *path,
55 int pathlen, struct vnode **newvp);
57 extern struct autofs_softc *autofs_softc;
60 autofs_access(struct vop_access_args *ap)
64 * Nothing to do here; the only kind of access control
65 * needed is in autofs_mkdir().
72 autofs_getattr(struct vop_getattr_args *ap)
74 struct vnode *vp, *newvp;
75 struct autofs_node *anp;
85 KASSERT(ap->a_vp->v_type == VDIR, ("!VDIR"));
88 * The reason we must do this is that some tree-walking software,
89 * namely fts(3), assumes that stat(".") results will not change
90 * between chdir("subdir") and chdir(".."), and fails with ENOENT
93 if (autofs_mount_on_stat && autofs_cached(anp, NULL, 0) == false &&
94 autofs_ignore_thread(curthread) == false) {
95 error = autofs_trigger_vn(vp, "", 0, &newvp);
100 error = VOP_GETATTR(newvp, ap->a_vap,
109 vap->va_nlink = 3; /* XXX */
112 vap->va_rdev = NODEV;
113 vap->va_fsid = mp->mnt_stat.f_fsid.val[0];
114 vap->va_fileid = anp->an_fileno;
115 vap->va_size = S_BLKSIZE;
116 vap->va_blocksize = S_BLKSIZE;
117 vap->va_mtime = anp->an_ctime;
118 vap->va_atime = anp->an_ctime;
119 vap->va_ctime = anp->an_ctime;
120 vap->va_birthtime = anp->an_ctime;
124 vap->va_bytes = S_BLKSIZE;
132 * Unlock the vnode, request automountd(8) action, and then lock it back.
133 * If anything got mounted on top of the vnode, return the new filesystem's
134 * root vnode in 'newvp', locked.
137 autofs_trigger_vn(struct vnode *vp, const char *path, int pathlen,
138 struct vnode **newvp)
140 struct autofs_node *anp;
141 int error, lock_flags;
146 * Release the vnode lock, so that other operations, in partcular
147 * mounting a filesystem on top of it, can proceed. Increase use
148 * count, to prevent the vnode from being deallocated and to prevent
149 * filesystem from being unmounted.
151 lock_flags = VOP_ISLOCKED(vp);
155 sx_xlock(&autofs_softc->sc_lock);
158 * XXX: Workaround for mounting the same thing multiple times; revisit.
160 if (vp->v_mountedhere != NULL) {
165 error = autofs_trigger(anp, path, pathlen);
167 sx_xunlock(&autofs_softc->sc_lock);
168 vn_lock(vp, lock_flags | LK_RETRY);
170 if ((vp->v_iflag & VI_DOOMED) != 0) {
171 AUTOFS_DEBUG("VI_DOOMED");
178 if (vp->v_mountedhere == NULL) {
183 * If the operation that succeeded was mount, then mark
184 * the node as non-cached. Otherwise, if someone unmounts
185 * the filesystem before the cache times out, we will fail
188 anp->an_cached = false;
191 error = VFS_ROOT(vp->v_mountedhere, lock_flags, newvp);
193 AUTOFS_WARN("VFS_ROOT() failed with error %d", error);
201 autofs_vget_callback(struct mount *mp, void *arg, int flags,
206 return (autofs_node_vn(arg, mp, flags, vpp));
210 autofs_lookup(struct vop_lookup_args *ap)
212 struct vnode *dvp, *newvp, **vpp;
214 struct autofs_mount *amp;
215 struct autofs_node *anp, *child;
216 struct componentname *cnp;
222 amp = VFSTOAUTOFS(mp);
226 if (cnp->cn_flags & ISDOTDOT) {
227 KASSERT(anp->an_parent != NULL, ("NULL parent"));
229 * Note that in this case, dvp is the child vnode, and we
230 * are looking up the parent vnode - exactly reverse from
231 * normal operation. Unlocking dvp requires some rather
232 * tricky unlock/relock dance to prevent mp from being freed;
233 * use vn_vget_ino_gen() which takes care of all that.
235 error = vn_vget_ino_gen(dvp, autofs_vget_callback,
236 anp->an_parent, cnp->cn_lkflags, vpp);
238 AUTOFS_WARN("vn_vget_ino_gen() failed with error %d",
245 if (cnp->cn_namelen == 1 && cnp->cn_nameptr[0] == '.') {
252 if (autofs_cached(anp, cnp->cn_nameptr, cnp->cn_namelen) == false &&
253 autofs_ignore_thread(cnp->cn_thread) == false) {
254 error = autofs_trigger_vn(dvp,
255 cnp->cn_nameptr, cnp->cn_namelen, &newvp);
261 * The target filesystem got automounted.
262 * Let the lookup(9) go around with the same
271 error = autofs_node_find(anp, cnp->cn_nameptr, cnp->cn_namelen, &child);
273 if ((cnp->cn_flags & ISLASTCN) && cnp->cn_nameiop == CREATE) {
275 return (EJUSTRETURN);
283 * XXX: Dropping the node here is ok, because we never remove nodes.
287 error = autofs_node_vn(child, mp, cnp->cn_lkflags, vpp);
289 if ((cnp->cn_flags & ISLASTCN) && cnp->cn_nameiop == CREATE)
290 return (EJUSTRETURN);
299 autofs_mkdir(struct vop_mkdir_args *ap)
302 struct autofs_node *anp;
303 struct autofs_mount *amp;
304 struct autofs_node *child;
309 amp = VFSTOAUTOFS(vp->v_mount);
312 * Do not allow mkdir() if the calling thread is not
313 * automountd(8) descendant.
315 if (autofs_ignore_thread(curthread) == false)
319 error = autofs_node_new(anp, amp, ap->a_cnp->cn_nameptr,
320 ap->a_cnp->cn_namelen, &child);
327 error = autofs_node_vn(child, vp->v_mount, LK_EXCLUSIVE, ap->a_vpp);
333 autofs_print(struct vop_print_args *ap)
336 struct autofs_node *anp;
341 printf(" name \"%s\", fileno %d, cached %d, wildcards %d\n",
342 anp->an_name, anp->an_fileno, anp->an_cached, anp->an_wildcards);
348 * Write out a single 'struct dirent', based on 'name' and 'fileno' arguments.
351 autofs_readdir_one(struct uio *uio, const char *name, int fileno,
354 struct dirent dirent;
355 size_t namlen, padded_namlen, reclen;
358 namlen = strlen(name);
359 padded_namlen = roundup2(namlen + 1, __alignof(struct dirent));
360 KASSERT(padded_namlen <= MAXNAMLEN, ("%zd > MAXNAMLEN", padded_namlen));
361 reclen = offsetof(struct dirent, d_name) + padded_namlen;
369 if (uio->uio_resid < reclen)
372 dirent.d_fileno = fileno;
373 dirent.d_reclen = reclen;
374 dirent.d_type = DT_DIR;
375 dirent.d_namlen = namlen;
376 memcpy(dirent.d_name, name, namlen);
377 memset(dirent.d_name + namlen, 0, padded_namlen - namlen);
378 error = uiomove(&dirent, reclen, uio);
384 autofs_dirent_reclen(const char *name)
388 (void)autofs_readdir_one(NULL, name, -1, &reclen);
394 autofs_readdir(struct vop_readdir_args *ap)
396 struct vnode *vp, *newvp;
397 struct autofs_mount *amp;
398 struct autofs_node *anp, *child;
400 size_t reclen, reclens;
401 ssize_t initial_resid;
405 amp = VFSTOAUTOFS(vp->v_mount);
408 initial_resid = ap->a_uio->uio_resid;
410 KASSERT(vp->v_type == VDIR, ("!VDIR"));
412 if (autofs_cached(anp, NULL, 0) == false &&
413 autofs_ignore_thread(curthread) == false) {
414 error = autofs_trigger_vn(vp, "", 0, &newvp);
419 error = VOP_READDIR(newvp, ap->a_uio, ap->a_cred,
420 ap->a_eofflag, ap->a_ncookies, ap->a_cookies);
426 if (uio->uio_offset < 0)
429 if (ap->a_eofflag != NULL)
430 *ap->a_eofflag = FALSE;
433 * Write out the directory entry for ".". This is conditional
434 * on the current offset into the directory; same applies to the
435 * other two cases below.
437 if (uio->uio_offset == 0) {
438 error = autofs_readdir_one(uio, ".", anp->an_fileno, &reclen);
442 reclens = autofs_dirent_reclen(".");
445 * Write out the directory entry for "..".
447 if (uio->uio_offset <= reclens) {
448 if (uio->uio_offset != reclens)
450 if (anp->an_parent == NULL) {
451 error = autofs_readdir_one(uio, "..",
452 anp->an_fileno, &reclen);
454 error = autofs_readdir_one(uio, "..",
455 anp->an_parent->an_fileno, &reclen);
461 reclens += autofs_dirent_reclen("..");
464 * Write out the directory entries for subdirectories.
467 RB_FOREACH(child, autofs_node_tree, &anp->an_children) {
469 * Check the offset to skip entries returned by previous
470 * calls to getdents().
472 if (uio->uio_offset > reclens) {
473 reclens += autofs_dirent_reclen(child->an_name);
478 * Prevent seeking into the middle of dirent.
480 if (uio->uio_offset != reclens) {
485 error = autofs_readdir_one(uio, child->an_name,
486 child->an_fileno, &reclen);
495 if (ap->a_eofflag != NULL)
496 *ap->a_eofflag = TRUE;
502 * Return error if the initial buffer was too small to do anything.
504 if (uio->uio_resid == initial_resid)
508 * Don't return an error if we managed to copy out some entries.
510 if (uio->uio_resid < reclen)
517 autofs_reclaim(struct vop_reclaim_args *ap)
520 struct autofs_node *anp;
526 * We do not free autofs_node here; instead we are
527 * destroying them in autofs_node_delete().
529 sx_xlock(&anp->an_vnode_lock);
530 anp->an_vnode = NULL;
532 sx_xunlock(&anp->an_vnode_lock);
537 struct vop_vector autofs_vnodeops = {
538 .vop_default = &default_vnodeops,
540 .vop_access = autofs_access,
541 .vop_lookup = autofs_lookup,
542 .vop_create = VOP_EOPNOTSUPP,
543 .vop_getattr = autofs_getattr,
544 .vop_link = VOP_EOPNOTSUPP,
545 .vop_mkdir = autofs_mkdir,
546 .vop_mknod = VOP_EOPNOTSUPP,
547 .vop_print = autofs_print,
548 .vop_read = VOP_EOPNOTSUPP,
549 .vop_readdir = autofs_readdir,
550 .vop_remove = VOP_EOPNOTSUPP,
551 .vop_rename = VOP_EOPNOTSUPP,
552 .vop_rmdir = VOP_EOPNOTSUPP,
553 .vop_setattr = VOP_EOPNOTSUPP,
554 .vop_symlink = VOP_EOPNOTSUPP,
555 .vop_write = VOP_EOPNOTSUPP,
556 .vop_reclaim = autofs_reclaim,
560 autofs_node_new(struct autofs_node *parent, struct autofs_mount *amp,
561 const char *name, int namelen, struct autofs_node **anpp)
563 struct autofs_node *anp;
565 if (parent != NULL) {
566 AUTOFS_ASSERT_XLOCKED(parent->an_mount);
568 KASSERT(autofs_node_find(parent, name, namelen, NULL) == ENOENT,
569 ("node \"%s\" already exists", name));
572 anp = uma_zalloc(autofs_node_zone, M_WAITOK | M_ZERO);
574 anp->an_name = strndup(name, namelen, M_AUTOFS);
576 anp->an_name = strdup(name, M_AUTOFS);
577 anp->an_fileno = atomic_fetchadd_int(&->am_last_fileno, 1);
578 callout_init(&anp->an_callout, 1);
580 * The reason for SX_NOWITNESS here is that witness(4)
581 * cannot tell vnodes apart, so the following perfectly
582 * valid lock order...
584 * vnode lock A -> autofsvlk B -> vnode lock B
586 * ... gets reported as a LOR.
588 sx_init_flags(&anp->an_vnode_lock, "autofsvlk", SX_NOWITNESS);
589 getnanotime(&anp->an_ctime);
590 anp->an_parent = parent;
593 RB_INSERT(autofs_node_tree, &parent->an_children, anp);
594 RB_INIT(&anp->an_children);
601 autofs_node_find(struct autofs_node *parent, const char *name,
602 int namelen, struct autofs_node **anpp)
604 struct autofs_node *anp, find;
607 AUTOFS_ASSERT_LOCKED(parent->an_mount);
610 find.an_name = strndup(name, namelen, M_AUTOFS);
612 find.an_name = strdup(name, M_AUTOFS);
614 anp = RB_FIND(autofs_node_tree, &parent->an_children, &find);
623 free(find.an_name, M_AUTOFS);
629 autofs_node_delete(struct autofs_node *anp)
631 struct autofs_node *parent;
633 AUTOFS_ASSERT_XLOCKED(anp->an_mount);
634 KASSERT(RB_EMPTY(&anp->an_children), ("have children"));
636 callout_drain(&anp->an_callout);
638 parent = anp->an_parent;
640 RB_REMOVE(autofs_node_tree, &parent->an_children, anp);
641 sx_destroy(&anp->an_vnode_lock);
642 free(anp->an_name, M_AUTOFS);
643 uma_zfree(autofs_node_zone, anp);
647 autofs_node_vn(struct autofs_node *anp, struct mount *mp, int flags,
653 AUTOFS_ASSERT_UNLOCKED(anp->an_mount);
655 sx_xlock(&anp->an_vnode_lock);
659 error = vget(vp, flags | LK_RETRY, curthread);
661 AUTOFS_WARN("vget failed with error %d", error);
662 sx_xunlock(&anp->an_vnode_lock);
665 if (vp->v_iflag & VI_DOOMED) {
667 * We got forcibly unmounted.
669 AUTOFS_DEBUG("doomed vnode");
670 sx_xunlock(&anp->an_vnode_lock);
677 sx_xunlock(&anp->an_vnode_lock);
681 error = getnewvnode("autofs", mp, &autofs_vnodeops, &vp);
683 sx_xunlock(&anp->an_vnode_lock);
687 error = vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
689 sx_xunlock(&anp->an_vnode_lock);
695 if (anp->an_parent == NULL)
696 vp->v_vflag |= VV_ROOT;
701 error = insmntque(vp, mp);
703 AUTOFS_DEBUG("insmntque() failed with error %d", error);
704 sx_xunlock(&anp->an_vnode_lock);
708 KASSERT(anp->an_vnode == NULL, ("lost race"));
711 sx_xunlock(&anp->an_vnode_lock);