1 /* -*- c -*- --------------------------------------------------------------- *
3 * linux/fs/autofs/root.c
5 * Copyright 1997-1998 Transmeta Corporation -- All Rights Reserved
6 * Copyright 1999-2000 Jeremy Fitzhardinge <jeremy@goop.org>
7 * Copyright 2001-2006 Ian Kent <raven@themaw.net>
9 * This file is part of the Linux kernel and is made available under
10 * the terms of the GNU General Public License, version 2, or at your
11 * option, any later version, incorporated herein by reference.
13 * ------------------------------------------------------------------------- */
15 #include <linux/capability.h>
16 #include <linux/errno.h>
17 #include <linux/stat.h>
18 #include <linux/param.h>
19 #include <linux/time.h>
22 static int autofs4_dir_symlink(struct inode *,struct dentry *,const char *);
23 static int autofs4_dir_unlink(struct inode *,struct dentry *);
24 static int autofs4_dir_rmdir(struct inode *,struct dentry *);
25 static int autofs4_dir_mkdir(struct inode *,struct dentry *,int);
26 static int autofs4_root_ioctl(struct inode *, struct file *,unsigned int,unsigned long);
27 static int autofs4_dir_open(struct inode *inode, struct file *file);
28 static struct dentry *autofs4_lookup(struct inode *,struct dentry *, struct nameidata *);
29 static void *autofs4_follow_link(struct dentry *, struct nameidata *);
31 #define TRIGGER_FLAGS (LOOKUP_CONTINUE | LOOKUP_DIRECTORY)
32 #define TRIGGER_INTENTS (LOOKUP_OPEN | LOOKUP_CREATE)
34 const struct file_operations autofs4_root_operations = {
35 .open = dcache_dir_open,
36 .release = dcache_dir_close,
37 .read = generic_read_dir,
38 .readdir = dcache_readdir,
39 .llseek = dcache_dir_lseek,
40 .ioctl = autofs4_root_ioctl,
43 const struct file_operations autofs4_dir_operations = {
44 .open = autofs4_dir_open,
45 .release = dcache_dir_close,
46 .read = generic_read_dir,
47 .readdir = dcache_readdir,
48 .llseek = dcache_dir_lseek,
51 const struct inode_operations autofs4_indirect_root_inode_operations = {
52 .lookup = autofs4_lookup,
53 .unlink = autofs4_dir_unlink,
54 .symlink = autofs4_dir_symlink,
55 .mkdir = autofs4_dir_mkdir,
56 .rmdir = autofs4_dir_rmdir,
59 const struct inode_operations autofs4_direct_root_inode_operations = {
60 .lookup = autofs4_lookup,
61 .unlink = autofs4_dir_unlink,
62 .mkdir = autofs4_dir_mkdir,
63 .rmdir = autofs4_dir_rmdir,
64 .follow_link = autofs4_follow_link,
67 const struct inode_operations autofs4_dir_inode_operations = {
68 .lookup = autofs4_lookup,
69 .unlink = autofs4_dir_unlink,
70 .symlink = autofs4_dir_symlink,
71 .mkdir = autofs4_dir_mkdir,
72 .rmdir = autofs4_dir_rmdir,
75 static void autofs4_add_active(struct dentry *dentry)
77 struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
78 struct autofs_info *ino = autofs4_dentry_ino(dentry);
80 spin_lock(&sbi->lookup_lock);
81 if (!ino->active_count) {
82 if (list_empty(&ino->active))
83 list_add(&ino->active, &sbi->active_list);
86 spin_unlock(&sbi->lookup_lock);
91 static void autofs4_del_active(struct dentry *dentry)
93 struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
94 struct autofs_info *ino = autofs4_dentry_ino(dentry);
96 spin_lock(&sbi->lookup_lock);
98 if (!ino->active_count) {
99 if (!list_empty(&ino->active))
100 list_del_init(&ino->active);
102 spin_unlock(&sbi->lookup_lock);
107 static unsigned int autofs4_need_mount(unsigned int flags)
109 unsigned int res = 0;
110 if (flags & (TRIGGER_FLAGS | TRIGGER_INTENTS))
115 static int autofs4_dir_open(struct inode *inode, struct file *file)
117 struct dentry *dentry = file->f_path.dentry;
118 struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
120 DPRINTK("file=%p dentry=%p %.*s",
121 file, dentry, dentry->d_name.len, dentry->d_name.name);
123 if (autofs4_oz_mode(sbi))
127 * An empty directory in an autofs file system is always a
128 * mount point. The daemon must have failed to mount this
129 * during lookup so it doesn't exist. This can happen, for
130 * example, if user space returns an incorrect status for a
131 * mount request. Otherwise we're doing a readdir on the
132 * autofs file system so just let the libfs routines handle
135 spin_lock(&dcache_lock);
136 if (!d_mountpoint(dentry) && __simple_empty(dentry)) {
137 spin_unlock(&dcache_lock);
140 spin_unlock(&dcache_lock);
143 return dcache_dir_open(inode, file);
146 static int try_to_fill_dentry(struct dentry *dentry, int flags)
148 struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
149 struct autofs_info *ino = autofs4_dentry_ino(dentry);
152 DPRINTK("dentry=%p %.*s ino=%p",
153 dentry, dentry->d_name.len, dentry->d_name.name, dentry->d_inode);
156 * Wait for a pending mount, triggering one if there
159 if (dentry->d_inode == NULL) {
160 DPRINTK("waiting for mount name=%.*s",
161 dentry->d_name.len, dentry->d_name.name);
163 status = autofs4_wait(sbi, dentry, NFY_MOUNT);
165 DPRINTK("mount done status=%d", status);
167 /* Turn this into a real negative dentry? */
168 if (status == -ENOENT) {
169 spin_lock(&sbi->fs_lock);
170 ino->flags &= ~AUTOFS_INF_PENDING;
171 spin_unlock(&sbi->fs_lock);
174 /* Return a negative dentry, but leave it "pending" */
177 /* Trigger mount for path component or follow link */
178 } else if (ino->flags & AUTOFS_INF_PENDING ||
179 autofs4_need_mount(flags) ||
180 current->link_count) {
181 DPRINTK("waiting for mount name=%.*s",
182 dentry->d_name.len, dentry->d_name.name);
184 spin_lock(&sbi->fs_lock);
185 ino->flags |= AUTOFS_INF_PENDING;
186 spin_unlock(&sbi->fs_lock);
187 status = autofs4_wait(sbi, dentry, NFY_MOUNT);
189 DPRINTK("mount done status=%d", status);
192 spin_lock(&sbi->fs_lock);
193 ino->flags &= ~AUTOFS_INF_PENDING;
194 spin_unlock(&sbi->fs_lock);
199 /* Initialize expiry counter after successful mount */
201 ino->last_used = jiffies;
203 spin_lock(&sbi->fs_lock);
204 ino->flags &= ~AUTOFS_INF_PENDING;
205 spin_unlock(&sbi->fs_lock);
210 /* For autofs direct mounts the follow link triggers the mount */
211 static void *autofs4_follow_link(struct dentry *dentry, struct nameidata *nd)
213 struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
214 struct autofs_info *ino = autofs4_dentry_ino(dentry);
215 int oz_mode = autofs4_oz_mode(sbi);
216 unsigned int lookup_type;
219 DPRINTK("dentry=%p %.*s oz_mode=%d nd->flags=%d",
220 dentry, dentry->d_name.len, dentry->d_name.name, oz_mode,
223 * For an expire of a covered direct or offset mount we need
224 * to break out of follow_down() at the autofs mount trigger
225 * (d_mounted--), so we can see the expiring flag, and manage
226 * the blocking and following here until the expire is completed.
229 spin_lock(&sbi->fs_lock);
230 if (ino->flags & AUTOFS_INF_EXPIRING) {
231 spin_unlock(&sbi->fs_lock);
232 /* Follow down to our covering mount. */
233 if (!follow_down(&nd->path))
237 spin_unlock(&sbi->fs_lock);
241 /* If an expire request is pending everyone must wait. */
242 autofs4_expire_wait(dentry);
244 /* We trigger a mount for almost all flags */
245 lookup_type = autofs4_need_mount(nd->flags);
246 spin_lock(&sbi->fs_lock);
247 spin_lock(&dcache_lock);
248 if (!(lookup_type || ino->flags & AUTOFS_INF_PENDING)) {
249 spin_unlock(&dcache_lock);
250 spin_unlock(&sbi->fs_lock);
255 * If the dentry contains directories then it is an autofs
256 * multi-mount with no root mount offset. So don't try to
259 if (ino->flags & AUTOFS_INF_PENDING ||
260 (!d_mountpoint(dentry) && __simple_empty(dentry))) {
261 spin_unlock(&dcache_lock);
262 spin_unlock(&sbi->fs_lock);
264 status = try_to_fill_dentry(dentry, 0);
270 spin_unlock(&dcache_lock);
271 spin_unlock(&sbi->fs_lock);
274 * If there is no root mount it must be an autofs
275 * multi-mount with no root offset so we don't need
278 if (d_mountpoint(dentry)) {
279 if (!autofs4_follow_mount(&nd->path)) {
290 return ERR_PTR(status);
294 * Revalidate is called on every cache lookup. Some of those
295 * cache lookups may actually happen while the dentry is not
296 * yet completely filled in, and revalidate has to delay such
299 static int autofs4_revalidate(struct dentry *dentry, struct nameidata *nd)
301 struct inode *dir = dentry->d_parent->d_inode;
302 struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb);
303 int oz_mode = autofs4_oz_mode(sbi);
304 int flags = nd ? nd->flags : 0;
308 spin_lock(&sbi->fs_lock);
309 if (autofs4_ispending(dentry)) {
310 /* The daemon never causes a mount to trigger */
311 spin_unlock(&sbi->fs_lock);
317 * If the directory has gone away due to an expire
318 * we have been called as ->d_revalidate() and so
319 * we need to return false and proceed to ->lookup().
321 if (autofs4_expire_wait(dentry) == -EAGAIN)
325 * A zero status is success otherwise we have a
326 * negative error code.
328 status = try_to_fill_dentry(dentry, flags);
334 spin_unlock(&sbi->fs_lock);
336 /* Negative dentry.. invalidate if "old" */
337 if (dentry->d_inode == NULL)
340 /* Check for a non-mountpoint directory with no contents */
341 spin_lock(&dcache_lock);
342 if (S_ISDIR(dentry->d_inode->i_mode) &&
343 !d_mountpoint(dentry) &&
344 __simple_empty(dentry)) {
345 DPRINTK("dentry=%p %.*s, emptydir",
346 dentry, dentry->d_name.len, dentry->d_name.name);
347 spin_unlock(&dcache_lock);
349 /* The daemon never causes a mount to trigger */
354 * A zero status is success otherwise we have a
355 * negative error code.
357 status = try_to_fill_dentry(dentry, flags);
363 spin_unlock(&dcache_lock);
368 void autofs4_dentry_release(struct dentry *de)
370 struct autofs_info *inf;
372 DPRINTK("releasing %p", de);
374 inf = autofs4_dentry_ino(de);
378 struct autofs_sb_info *sbi = autofs4_sbi(de->d_sb);
381 spin_lock(&sbi->lookup_lock);
382 if (!list_empty(&inf->active))
383 list_del(&inf->active);
384 if (!list_empty(&inf->expiring))
385 list_del(&inf->expiring);
386 spin_unlock(&sbi->lookup_lock);
392 autofs4_free_ino(inf);
396 /* For dentries of directories in the root dir */
397 static const struct dentry_operations autofs4_root_dentry_operations = {
398 .d_revalidate = autofs4_revalidate,
399 .d_release = autofs4_dentry_release,
402 /* For other dentries */
403 static const struct dentry_operations autofs4_dentry_operations = {
404 .d_revalidate = autofs4_revalidate,
405 .d_release = autofs4_dentry_release,
408 static struct dentry *autofs4_lookup_active(struct dentry *dentry)
410 struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
411 struct dentry *parent = dentry->d_parent;
412 struct qstr *name = &dentry->d_name;
413 unsigned int len = name->len;
414 unsigned int hash = name->hash;
415 const unsigned char *str = name->name;
416 struct list_head *p, *head;
418 spin_lock(&dcache_lock);
419 spin_lock(&sbi->lookup_lock);
420 head = &sbi->active_list;
421 list_for_each(p, head) {
422 struct autofs_info *ino;
423 struct dentry *dentry;
426 ino = list_entry(p, struct autofs_info, active);
427 dentry = ino->dentry;
429 spin_lock(&dentry->d_lock);
432 if (atomic_read(&dentry->d_count) == 0)
435 qstr = &dentry->d_name;
437 if (dentry->d_name.hash != hash)
439 if (dentry->d_parent != parent)
442 if (qstr->len != len)
444 if (memcmp(qstr->name, str, len))
447 if (d_unhashed(dentry)) {
449 spin_unlock(&dentry->d_lock);
450 spin_unlock(&sbi->lookup_lock);
451 spin_unlock(&dcache_lock);
455 spin_unlock(&dentry->d_lock);
457 spin_unlock(&sbi->lookup_lock);
458 spin_unlock(&dcache_lock);
463 static struct dentry *autofs4_lookup_expiring(struct dentry *dentry)
465 struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
466 struct dentry *parent = dentry->d_parent;
467 struct qstr *name = &dentry->d_name;
468 unsigned int len = name->len;
469 unsigned int hash = name->hash;
470 const unsigned char *str = name->name;
471 struct list_head *p, *head;
473 spin_lock(&dcache_lock);
474 spin_lock(&sbi->lookup_lock);
475 head = &sbi->expiring_list;
476 list_for_each(p, head) {
477 struct autofs_info *ino;
478 struct dentry *dentry;
481 ino = list_entry(p, struct autofs_info, expiring);
482 dentry = ino->dentry;
484 spin_lock(&dentry->d_lock);
486 /* Bad luck, we've already been dentry_iput */
487 if (!dentry->d_inode)
490 qstr = &dentry->d_name;
492 if (dentry->d_name.hash != hash)
494 if (dentry->d_parent != parent)
497 if (qstr->len != len)
499 if (memcmp(qstr->name, str, len))
502 if (d_unhashed(dentry)) {
504 spin_unlock(&dentry->d_lock);
505 spin_unlock(&sbi->lookup_lock);
506 spin_unlock(&dcache_lock);
510 spin_unlock(&dentry->d_lock);
512 spin_unlock(&sbi->lookup_lock);
513 spin_unlock(&dcache_lock);
518 /* Lookups in the root directory */
519 static struct dentry *autofs4_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd)
521 struct autofs_sb_info *sbi;
522 struct autofs_info *ino;
523 struct dentry *expiring, *active;
526 DPRINTK("name = %.*s",
527 dentry->d_name.len, dentry->d_name.name);
529 /* File name too long to exist */
530 if (dentry->d_name.len > NAME_MAX)
531 return ERR_PTR(-ENAMETOOLONG);
533 sbi = autofs4_sbi(dir->i_sb);
534 oz_mode = autofs4_oz_mode(sbi);
536 DPRINTK("pid = %u, pgrp = %u, catatonic = %d, oz_mode = %d",
537 current->pid, task_pgrp_nr(current), sbi->catatonic, oz_mode);
539 active = autofs4_lookup_active(dentry);
542 ino = autofs4_dentry_ino(dentry);
545 * Mark the dentry incomplete but don't hash it. We do this
546 * to serialize our inode creation operations (symlink and
547 * mkdir) which prevents deadlock during the callback to
548 * the daemon. Subsequent user space lookups for the same
549 * dentry are placed on the wait queue while the daemon
550 * itself is allowed passage unresticted so the create
551 * operation itself can then hash the dentry. Finally,
552 * we check for the hashed dentry and return the newly
555 dentry->d_op = &autofs4_root_dentry_operations;
558 * And we need to ensure that the same dentry is used for
559 * all following lookup calls until it is hashed so that
560 * the dentry flags are persistent throughout the request.
562 ino = autofs4_init_ino(NULL, sbi, 0555);
564 return ERR_PTR(-ENOMEM);
566 dentry->d_fsdata = ino;
567 ino->dentry = dentry;
569 autofs4_add_active(dentry);
571 d_instantiate(dentry, NULL);
575 mutex_unlock(&dir->i_mutex);
576 expiring = autofs4_lookup_expiring(dentry);
579 * If we are racing with expire the request might not
580 * be quite complete but the directory has been removed
581 * so it must have been successful, so just wait for it.
583 autofs4_expire_wait(expiring);
584 autofs4_del_expiring(expiring);
588 spin_lock(&sbi->fs_lock);
589 ino->flags |= AUTOFS_INF_PENDING;
590 spin_unlock(&sbi->fs_lock);
591 if (dentry->d_op && dentry->d_op->d_revalidate)
592 (dentry->d_op->d_revalidate)(dentry, nd);
593 mutex_lock(&dir->i_mutex);
597 * If we are still pending, check if we had to handle
598 * a signal. If so we can force a restart..
600 if (ino->flags & AUTOFS_INF_PENDING) {
601 /* See if we were interrupted */
602 if (signal_pending(current)) {
603 sigset_t *sigset = ¤t->pending.signal;
604 if (sigismember (sigset, SIGKILL) ||
605 sigismember (sigset, SIGQUIT) ||
606 sigismember (sigset, SIGINT)) {
609 return ERR_PTR(-ERESTARTNOINTR);
613 spin_lock(&sbi->fs_lock);
614 ino->flags &= ~AUTOFS_INF_PENDING;
615 spin_unlock(&sbi->fs_lock);
620 * If this dentry is unhashed, then we shouldn't honour this
621 * lookup. Returning ENOENT here doesn't do the right thing
622 * for all system calls, but it should be OK for the operations
623 * we permit from an autofs.
625 if (!oz_mode && d_unhashed(dentry)) {
627 * A user space application can (and has done in the past)
628 * remove and re-create this directory during the callback.
629 * This can leave us with an unhashed dentry, but a
630 * successful mount! So we need to perform another
631 * cached lookup in case the dentry now exists.
633 struct dentry *parent = dentry->d_parent;
634 struct dentry *new = d_lookup(parent, &dentry->d_name);
638 dentry = ERR_PTR(-ENOENT);
652 static int autofs4_dir_symlink(struct inode *dir,
653 struct dentry *dentry,
656 struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb);
657 struct autofs_info *ino = autofs4_dentry_ino(dentry);
658 struct autofs_info *p_ino;
662 DPRINTK("%s <- %.*s", symname,
663 dentry->d_name.len, dentry->d_name.name);
665 if (!autofs4_oz_mode(sbi))
668 ino = autofs4_init_ino(ino, sbi, S_IFLNK | 0555);
672 autofs4_del_active(dentry);
674 ino->size = strlen(symname);
675 cp = kmalloc(ino->size + 1, GFP_KERNEL);
677 if (!dentry->d_fsdata)
684 inode = autofs4_get_inode(dir->i_sb, ino);
687 if (!dentry->d_fsdata)
691 d_add(dentry, inode);
693 if (dir == dir->i_sb->s_root->d_inode)
694 dentry->d_op = &autofs4_root_dentry_operations;
696 dentry->d_op = &autofs4_dentry_operations;
698 dentry->d_fsdata = ino;
699 ino->dentry = dget(dentry);
700 atomic_inc(&ino->count);
701 p_ino = autofs4_dentry_ino(dentry->d_parent);
702 if (p_ino && dentry->d_parent != dentry)
703 atomic_inc(&p_ino->count);
707 dir->i_mtime = CURRENT_TIME;
715 * Normal filesystems would do a "d_delete()" to tell the VFS dcache
716 * that the file no longer exists. However, doing that means that the
717 * VFS layer can turn the dentry into a negative dentry. We don't want
718 * this, because the unlink is probably the result of an expire.
719 * We simply d_drop it and add it to a expiring list in the super block,
720 * which allows the dentry lookup to check for an incomplete expire.
722 * If a process is blocked on the dentry waiting for the expire to finish,
723 * it will invalidate the dentry and try to mount with a new one.
725 * Also see autofs4_dir_rmdir()..
727 static int autofs4_dir_unlink(struct inode *dir, struct dentry *dentry)
729 struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb);
730 struct autofs_info *ino = autofs4_dentry_ino(dentry);
731 struct autofs_info *p_ino;
733 /* This allows root to remove symlinks */
734 if (!autofs4_oz_mode(sbi) && !capable(CAP_SYS_ADMIN))
737 if (atomic_dec_and_test(&ino->count)) {
738 p_ino = autofs4_dentry_ino(dentry->d_parent);
739 if (p_ino && dentry->d_parent != dentry)
740 atomic_dec(&p_ino->count);
744 dentry->d_inode->i_size = 0;
745 clear_nlink(dentry->d_inode);
747 dir->i_mtime = CURRENT_TIME;
749 spin_lock(&dcache_lock);
750 autofs4_add_expiring(dentry);
751 spin_lock(&dentry->d_lock);
753 spin_unlock(&dentry->d_lock);
754 spin_unlock(&dcache_lock);
759 static int autofs4_dir_rmdir(struct inode *dir, struct dentry *dentry)
761 struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb);
762 struct autofs_info *ino = autofs4_dentry_ino(dentry);
763 struct autofs_info *p_ino;
765 DPRINTK("dentry %p, removing %.*s",
766 dentry, dentry->d_name.len, dentry->d_name.name);
768 if (!autofs4_oz_mode(sbi))
771 spin_lock(&dcache_lock);
772 if (!list_empty(&dentry->d_subdirs)) {
773 spin_unlock(&dcache_lock);
776 autofs4_add_expiring(dentry);
777 spin_lock(&dentry->d_lock);
779 spin_unlock(&dentry->d_lock);
780 spin_unlock(&dcache_lock);
782 if (atomic_dec_and_test(&ino->count)) {
783 p_ino = autofs4_dentry_ino(dentry->d_parent);
784 if (p_ino && dentry->d_parent != dentry)
785 atomic_dec(&p_ino->count);
788 dentry->d_inode->i_size = 0;
789 clear_nlink(dentry->d_inode);
797 static int autofs4_dir_mkdir(struct inode *dir, struct dentry *dentry, int mode)
799 struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb);
800 struct autofs_info *ino = autofs4_dentry_ino(dentry);
801 struct autofs_info *p_ino;
804 if (!autofs4_oz_mode(sbi))
807 DPRINTK("dentry %p, creating %.*s",
808 dentry, dentry->d_name.len, dentry->d_name.name);
810 ino = autofs4_init_ino(ino, sbi, S_IFDIR | 0555);
814 autofs4_del_active(dentry);
816 inode = autofs4_get_inode(dir->i_sb, ino);
818 if (!dentry->d_fsdata)
822 d_add(dentry, inode);
824 if (dir == dir->i_sb->s_root->d_inode)
825 dentry->d_op = &autofs4_root_dentry_operations;
827 dentry->d_op = &autofs4_dentry_operations;
829 dentry->d_fsdata = ino;
830 ino->dentry = dget(dentry);
831 atomic_inc(&ino->count);
832 p_ino = autofs4_dentry_ino(dentry->d_parent);
833 if (p_ino && dentry->d_parent != dentry)
834 atomic_inc(&p_ino->count);
837 dir->i_mtime = CURRENT_TIME;
842 /* Get/set timeout ioctl() operation */
843 static inline int autofs4_get_set_timeout(struct autofs_sb_info *sbi,
844 unsigned long __user *p)
847 unsigned long ntimeout;
849 if ((rv = get_user(ntimeout, p)) ||
850 (rv = put_user(sbi->exp_timeout/HZ, p)))
853 if (ntimeout > ULONG_MAX/HZ)
854 sbi->exp_timeout = 0;
856 sbi->exp_timeout = ntimeout * HZ;
861 /* Return protocol version */
862 static inline int autofs4_get_protover(struct autofs_sb_info *sbi, int __user *p)
864 return put_user(sbi->version, p);
867 /* Return protocol sub version */
868 static inline int autofs4_get_protosubver(struct autofs_sb_info *sbi, int __user *p)
870 return put_user(sbi->sub_version, p);
874 * Tells the daemon whether it can umount the autofs mount.
876 static inline int autofs4_ask_umount(struct vfsmount *mnt, int __user *p)
883 DPRINTK("returning %d", status);
885 status = put_user(status, p);
890 /* Identify autofs4_dentries - this is so we can tell if there's
891 an extra dentry refcount or not. We only hold a refcount on the
892 dentry if its non-negative (ie, d_inode != NULL)
894 int is_autofs4_dentry(struct dentry *dentry)
896 return dentry && dentry->d_inode &&
897 (dentry->d_op == &autofs4_root_dentry_operations ||
898 dentry->d_op == &autofs4_dentry_operations) &&
899 dentry->d_fsdata != NULL;
903 * ioctl()'s on the root directory is the chief method for the daemon to
904 * generate kernel reactions
906 static int autofs4_root_ioctl(struct inode *inode, struct file *filp,
907 unsigned int cmd, unsigned long arg)
909 struct autofs_sb_info *sbi = autofs4_sbi(inode->i_sb);
910 void __user *p = (void __user *)arg;
912 DPRINTK("cmd = 0x%08x, arg = 0x%08lx, sbi = %p, pgrp = %u",
913 cmd,arg,sbi,task_pgrp_nr(current));
915 if (_IOC_TYPE(cmd) != _IOC_TYPE(AUTOFS_IOC_FIRST) ||
916 _IOC_NR(cmd) - _IOC_NR(AUTOFS_IOC_FIRST) >= AUTOFS_IOC_COUNT)
919 if (!autofs4_oz_mode(sbi) && !capable(CAP_SYS_ADMIN))
923 case AUTOFS_IOC_READY: /* Wait queue: go ahead and retry */
924 return autofs4_wait_release(sbi,(autofs_wqt_t)arg,0);
925 case AUTOFS_IOC_FAIL: /* Wait queue: fail with ENOENT */
926 return autofs4_wait_release(sbi,(autofs_wqt_t)arg,-ENOENT);
927 case AUTOFS_IOC_CATATONIC: /* Enter catatonic mode (daemon shutdown) */
928 autofs4_catatonic_mode(sbi);
930 case AUTOFS_IOC_PROTOVER: /* Get protocol version */
931 return autofs4_get_protover(sbi, p);
932 case AUTOFS_IOC_PROTOSUBVER: /* Get protocol sub version */
933 return autofs4_get_protosubver(sbi, p);
934 case AUTOFS_IOC_SETTIMEOUT:
935 return autofs4_get_set_timeout(sbi, p);
937 case AUTOFS_IOC_ASKUMOUNT:
938 return autofs4_ask_umount(filp->f_path.mnt, p);
940 /* return a single thing to expire */
941 case AUTOFS_IOC_EXPIRE:
942 return autofs4_expire_run(inode->i_sb,filp->f_path.mnt,sbi, p);
943 /* same as above, but can send multiple expires through pipe */
944 case AUTOFS_IOC_EXPIRE_MULTI:
945 return autofs4_expire_multi(inode->i_sb,filp->f_path.mnt,sbi, p);