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/slab.h>
19 #include <linux/param.h>
20 #include <linux/time.h>
23 static int autofs4_dir_symlink(struct inode *,struct dentry *,const char *);
24 static int autofs4_dir_unlink(struct inode *,struct dentry *);
25 static int autofs4_dir_rmdir(struct inode *,struct dentry *);
26 static int autofs4_dir_mkdir(struct inode *,struct dentry *,int);
27 static int autofs4_root_ioctl(struct inode *, struct file *,unsigned int,unsigned long);
28 static int autofs4_dir_open(struct inode *inode, struct file *file);
29 static struct dentry *autofs4_lookup(struct inode *,struct dentry *, struct nameidata *);
30 static void *autofs4_follow_link(struct dentry *, struct nameidata *);
32 #define TRIGGER_FLAGS (LOOKUP_CONTINUE | LOOKUP_DIRECTORY)
33 #define TRIGGER_INTENTS (LOOKUP_OPEN | LOOKUP_CREATE)
35 const struct file_operations autofs4_root_operations = {
36 .open = dcache_dir_open,
37 .release = dcache_dir_close,
38 .read = generic_read_dir,
39 .readdir = dcache_readdir,
40 .llseek = dcache_dir_lseek,
41 .ioctl = autofs4_root_ioctl,
44 const struct file_operations autofs4_dir_operations = {
45 .open = autofs4_dir_open,
46 .release = dcache_dir_close,
47 .read = generic_read_dir,
48 .readdir = dcache_readdir,
49 .llseek = dcache_dir_lseek,
52 const struct inode_operations autofs4_indirect_root_inode_operations = {
53 .lookup = autofs4_lookup,
54 .unlink = autofs4_dir_unlink,
55 .symlink = autofs4_dir_symlink,
56 .mkdir = autofs4_dir_mkdir,
57 .rmdir = autofs4_dir_rmdir,
60 const struct inode_operations autofs4_direct_root_inode_operations = {
61 .lookup = autofs4_lookup,
62 .unlink = autofs4_dir_unlink,
63 .mkdir = autofs4_dir_mkdir,
64 .rmdir = autofs4_dir_rmdir,
65 .follow_link = autofs4_follow_link,
68 const struct inode_operations autofs4_dir_inode_operations = {
69 .lookup = autofs4_lookup,
70 .unlink = autofs4_dir_unlink,
71 .symlink = autofs4_dir_symlink,
72 .mkdir = autofs4_dir_mkdir,
73 .rmdir = autofs4_dir_rmdir,
76 static void autofs4_add_active(struct dentry *dentry)
78 struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
79 struct autofs_info *ino = autofs4_dentry_ino(dentry);
81 spin_lock(&sbi->lookup_lock);
82 if (!ino->active_count) {
83 if (list_empty(&ino->active))
84 list_add(&ino->active, &sbi->active_list);
87 spin_unlock(&sbi->lookup_lock);
92 static void autofs4_del_active(struct dentry *dentry)
94 struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
95 struct autofs_info *ino = autofs4_dentry_ino(dentry);
97 spin_lock(&sbi->lookup_lock);
99 if (!ino->active_count) {
100 if (!list_empty(&ino->active))
101 list_del_init(&ino->active);
103 spin_unlock(&sbi->lookup_lock);
108 static unsigned int autofs4_need_mount(unsigned int flags)
110 unsigned int res = 0;
111 if (flags & (TRIGGER_FLAGS | TRIGGER_INTENTS))
116 static int autofs4_dir_open(struct inode *inode, struct file *file)
118 struct dentry *dentry = file->f_path.dentry;
119 struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
121 DPRINTK("file=%p dentry=%p %.*s",
122 file, dentry, dentry->d_name.len, dentry->d_name.name);
124 if (autofs4_oz_mode(sbi))
128 * An empty directory in an autofs file system is always a
129 * mount point. The daemon must have failed to mount this
130 * during lookup so it doesn't exist. This can happen, for
131 * example, if user space returns an incorrect status for a
132 * mount request. Otherwise we're doing a readdir on the
133 * autofs file system so just let the libfs routines handle
136 spin_lock(&dcache_lock);
137 if (!d_mountpoint(dentry) && list_empty(&dentry->d_subdirs)) {
138 spin_unlock(&dcache_lock);
141 spin_unlock(&dcache_lock);
144 return dcache_dir_open(inode, file);
147 static int try_to_fill_dentry(struct dentry *dentry, int flags)
149 struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
150 struct autofs_info *ino = autofs4_dentry_ino(dentry);
153 DPRINTK("dentry=%p %.*s ino=%p",
154 dentry, dentry->d_name.len, dentry->d_name.name, dentry->d_inode);
157 * Wait for a pending mount, triggering one if there
160 if (dentry->d_inode == NULL) {
161 DPRINTK("waiting for mount name=%.*s",
162 dentry->d_name.len, dentry->d_name.name);
164 status = autofs4_wait(sbi, dentry, NFY_MOUNT);
166 DPRINTK("mount done status=%d", status);
168 /* Turn this into a real negative dentry? */
169 if (status == -ENOENT) {
170 spin_lock(&sbi->fs_lock);
171 ino->flags &= ~AUTOFS_INF_PENDING;
172 spin_unlock(&sbi->fs_lock);
175 /* Return a negative dentry, but leave it "pending" */
178 /* Trigger mount for path component or follow link */
179 } else if (ino->flags & AUTOFS_INF_PENDING ||
180 autofs4_need_mount(flags)) {
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) && list_empty(&dentry->d_subdirs))) {
261 spin_unlock(&dcache_lock);
262 spin_unlock(&sbi->fs_lock);
264 status = try_to_fill_dentry(dentry, nd->flags);
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) && list_empty(&dentry->d_subdirs)) {
344 DPRINTK("dentry=%p %.*s, emptydir",
345 dentry, dentry->d_name.len, dentry->d_name.name);
346 spin_unlock(&dcache_lock);
348 /* The daemon never causes a mount to trigger */
353 * A zero status is success otherwise we have a
354 * negative error code.
356 status = try_to_fill_dentry(dentry, flags);
362 spin_unlock(&dcache_lock);
367 void autofs4_dentry_release(struct dentry *de)
369 struct autofs_info *inf;
371 DPRINTK("releasing %p", de);
373 inf = autofs4_dentry_ino(de);
377 struct autofs_sb_info *sbi = autofs4_sbi(de->d_sb);
380 spin_lock(&sbi->lookup_lock);
381 if (!list_empty(&inf->active))
382 list_del(&inf->active);
383 if (!list_empty(&inf->expiring))
384 list_del(&inf->expiring);
385 spin_unlock(&sbi->lookup_lock);
391 autofs4_free_ino(inf);
395 /* For dentries of directories in the root dir */
396 static const struct dentry_operations autofs4_root_dentry_operations = {
397 .d_revalidate = autofs4_revalidate,
398 .d_release = autofs4_dentry_release,
401 /* For other dentries */
402 static const struct dentry_operations autofs4_dentry_operations = {
403 .d_revalidate = autofs4_revalidate,
404 .d_release = autofs4_dentry_release,
407 static struct dentry *autofs4_lookup_active(struct dentry *dentry)
409 struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
410 struct dentry *parent = dentry->d_parent;
411 struct qstr *name = &dentry->d_name;
412 unsigned int len = name->len;
413 unsigned int hash = name->hash;
414 const unsigned char *str = name->name;
415 struct list_head *p, *head;
417 spin_lock(&dcache_lock);
418 spin_lock(&sbi->lookup_lock);
419 head = &sbi->active_list;
420 list_for_each(p, head) {
421 struct autofs_info *ino;
422 struct dentry *active;
425 ino = list_entry(p, struct autofs_info, active);
426 active = ino->dentry;
428 spin_lock(&active->d_lock);
431 if (atomic_read(&active->d_count) == 0)
434 qstr = &active->d_name;
436 if (active->d_name.hash != hash)
438 if (active->d_parent != parent)
441 if (qstr->len != len)
443 if (memcmp(qstr->name, str, len))
446 if (d_unhashed(active)) {
448 spin_unlock(&active->d_lock);
449 spin_unlock(&sbi->lookup_lock);
450 spin_unlock(&dcache_lock);
454 spin_unlock(&active->d_lock);
456 spin_unlock(&sbi->lookup_lock);
457 spin_unlock(&dcache_lock);
462 static struct dentry *autofs4_lookup_expiring(struct dentry *dentry)
464 struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
465 struct dentry *parent = dentry->d_parent;
466 struct qstr *name = &dentry->d_name;
467 unsigned int len = name->len;
468 unsigned int hash = name->hash;
469 const unsigned char *str = name->name;
470 struct list_head *p, *head;
472 spin_lock(&dcache_lock);
473 spin_lock(&sbi->lookup_lock);
474 head = &sbi->expiring_list;
475 list_for_each(p, head) {
476 struct autofs_info *ino;
477 struct dentry *expiring;
480 ino = list_entry(p, struct autofs_info, expiring);
481 expiring = ino->dentry;
483 spin_lock(&expiring->d_lock);
485 /* Bad luck, we've already been dentry_iput */
486 if (!expiring->d_inode)
489 qstr = &expiring->d_name;
491 if (expiring->d_name.hash != hash)
493 if (expiring->d_parent != parent)
496 if (qstr->len != len)
498 if (memcmp(qstr->name, str, len))
501 if (d_unhashed(expiring)) {
503 spin_unlock(&expiring->d_lock);
504 spin_unlock(&sbi->lookup_lock);
505 spin_unlock(&dcache_lock);
509 spin_unlock(&expiring->d_lock);
511 spin_unlock(&sbi->lookup_lock);
512 spin_unlock(&dcache_lock);
517 /* Lookups in the root directory */
518 static struct dentry *autofs4_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd)
520 struct autofs_sb_info *sbi;
521 struct autofs_info *ino;
522 struct dentry *expiring, *active;
525 DPRINTK("name = %.*s",
526 dentry->d_name.len, dentry->d_name.name);
528 /* File name too long to exist */
529 if (dentry->d_name.len > NAME_MAX)
530 return ERR_PTR(-ENAMETOOLONG);
532 sbi = autofs4_sbi(dir->i_sb);
533 oz_mode = autofs4_oz_mode(sbi);
535 DPRINTK("pid = %u, pgrp = %u, catatonic = %d, oz_mode = %d",
536 current->pid, task_pgrp_nr(current), sbi->catatonic, oz_mode);
538 active = autofs4_lookup_active(dentry);
541 ino = autofs4_dentry_ino(dentry);
544 * Mark the dentry incomplete but don't hash it. We do this
545 * to serialize our inode creation operations (symlink and
546 * mkdir) which prevents deadlock during the callback to
547 * the daemon. Subsequent user space lookups for the same
548 * dentry are placed on the wait queue while the daemon
549 * itself is allowed passage unresticted so the create
550 * operation itself can then hash the dentry. Finally,
551 * we check for the hashed dentry and return the newly
554 dentry->d_op = &autofs4_root_dentry_operations;
557 * And we need to ensure that the same dentry is used for
558 * all following lookup calls until it is hashed so that
559 * the dentry flags are persistent throughout the request.
561 ino = autofs4_init_ino(NULL, sbi, 0555);
563 return ERR_PTR(-ENOMEM);
565 dentry->d_fsdata = ino;
566 ino->dentry = dentry;
568 autofs4_add_active(dentry);
570 d_instantiate(dentry, NULL);
574 mutex_unlock(&dir->i_mutex);
575 expiring = autofs4_lookup_expiring(dentry);
578 * If we are racing with expire the request might not
579 * be quite complete but the directory has been removed
580 * so it must have been successful, so just wait for it.
582 autofs4_expire_wait(expiring);
583 autofs4_del_expiring(expiring);
587 spin_lock(&sbi->fs_lock);
588 ino->flags |= AUTOFS_INF_PENDING;
589 spin_unlock(&sbi->fs_lock);
590 if (dentry->d_op && dentry->d_op->d_revalidate)
591 (dentry->d_op->d_revalidate)(dentry, nd);
592 mutex_lock(&dir->i_mutex);
596 * If we are still pending, check if we had to handle
597 * a signal. If so we can force a restart..
599 if (ino->flags & AUTOFS_INF_PENDING) {
600 /* See if we were interrupted */
601 if (signal_pending(current)) {
602 sigset_t *sigset = ¤t->pending.signal;
603 if (sigismember (sigset, SIGKILL) ||
604 sigismember (sigset, SIGQUIT) ||
605 sigismember (sigset, SIGINT)) {
608 return ERR_PTR(-ERESTARTNOINTR);
612 spin_lock(&sbi->fs_lock);
613 ino->flags &= ~AUTOFS_INF_PENDING;
614 spin_unlock(&sbi->fs_lock);
619 * If this dentry is unhashed, then we shouldn't honour this
620 * lookup. Returning ENOENT here doesn't do the right thing
621 * for all system calls, but it should be OK for the operations
622 * we permit from an autofs.
624 if (!oz_mode && d_unhashed(dentry)) {
626 * A user space application can (and has done in the past)
627 * remove and re-create this directory during the callback.
628 * This can leave us with an unhashed dentry, but a
629 * successful mount! So we need to perform another
630 * cached lookup in case the dentry now exists.
632 struct dentry *parent = dentry->d_parent;
633 struct dentry *new = d_lookup(parent, &dentry->d_name);
637 dentry = ERR_PTR(-ENOENT);
651 static int autofs4_dir_symlink(struct inode *dir,
652 struct dentry *dentry,
655 struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb);
656 struct autofs_info *ino = autofs4_dentry_ino(dentry);
657 struct autofs_info *p_ino;
661 DPRINTK("%s <- %.*s", symname,
662 dentry->d_name.len, dentry->d_name.name);
664 if (!autofs4_oz_mode(sbi))
667 ino = autofs4_init_ino(ino, sbi, S_IFLNK | 0555);
671 autofs4_del_active(dentry);
673 ino->size = strlen(symname);
674 cp = kmalloc(ino->size + 1, GFP_KERNEL);
676 if (!dentry->d_fsdata)
683 inode = autofs4_get_inode(dir->i_sb, ino);
686 if (!dentry->d_fsdata)
690 d_add(dentry, inode);
692 if (dir == dir->i_sb->s_root->d_inode)
693 dentry->d_op = &autofs4_root_dentry_operations;
695 dentry->d_op = &autofs4_dentry_operations;
697 dentry->d_fsdata = ino;
698 ino->dentry = dget(dentry);
699 atomic_inc(&ino->count);
700 p_ino = autofs4_dentry_ino(dentry->d_parent);
701 if (p_ino && dentry->d_parent != dentry)
702 atomic_inc(&p_ino->count);
706 dir->i_mtime = CURRENT_TIME;
714 * Normal filesystems would do a "d_delete()" to tell the VFS dcache
715 * that the file no longer exists. However, doing that means that the
716 * VFS layer can turn the dentry into a negative dentry. We don't want
717 * this, because the unlink is probably the result of an expire.
718 * We simply d_drop it and add it to a expiring list in the super block,
719 * which allows the dentry lookup to check for an incomplete expire.
721 * If a process is blocked on the dentry waiting for the expire to finish,
722 * it will invalidate the dentry and try to mount with a new one.
724 * Also see autofs4_dir_rmdir()..
726 static int autofs4_dir_unlink(struct inode *dir, struct dentry *dentry)
728 struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb);
729 struct autofs_info *ino = autofs4_dentry_ino(dentry);
730 struct autofs_info *p_ino;
732 /* This allows root to remove symlinks */
733 if (!autofs4_oz_mode(sbi) && !capable(CAP_SYS_ADMIN))
736 if (atomic_dec_and_test(&ino->count)) {
737 p_ino = autofs4_dentry_ino(dentry->d_parent);
738 if (p_ino && dentry->d_parent != dentry)
739 atomic_dec(&p_ino->count);
743 dentry->d_inode->i_size = 0;
744 clear_nlink(dentry->d_inode);
746 dir->i_mtime = CURRENT_TIME;
748 spin_lock(&dcache_lock);
749 autofs4_add_expiring(dentry);
750 spin_lock(&dentry->d_lock);
752 spin_unlock(&dentry->d_lock);
753 spin_unlock(&dcache_lock);
758 static int autofs4_dir_rmdir(struct inode *dir, struct dentry *dentry)
760 struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb);
761 struct autofs_info *ino = autofs4_dentry_ino(dentry);
762 struct autofs_info *p_ino;
764 DPRINTK("dentry %p, removing %.*s",
765 dentry, dentry->d_name.len, dentry->d_name.name);
767 if (!autofs4_oz_mode(sbi))
770 spin_lock(&dcache_lock);
771 if (!list_empty(&dentry->d_subdirs)) {
772 spin_unlock(&dcache_lock);
775 autofs4_add_expiring(dentry);
776 spin_lock(&dentry->d_lock);
778 spin_unlock(&dentry->d_lock);
779 spin_unlock(&dcache_lock);
781 if (atomic_dec_and_test(&ino->count)) {
782 p_ino = autofs4_dentry_ino(dentry->d_parent);
783 if (p_ino && dentry->d_parent != dentry)
784 atomic_dec(&p_ino->count);
787 dentry->d_inode->i_size = 0;
788 clear_nlink(dentry->d_inode);
796 static int autofs4_dir_mkdir(struct inode *dir, struct dentry *dentry, int mode)
798 struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb);
799 struct autofs_info *ino = autofs4_dentry_ino(dentry);
800 struct autofs_info *p_ino;
803 if (!autofs4_oz_mode(sbi))
806 DPRINTK("dentry %p, creating %.*s",
807 dentry, dentry->d_name.len, dentry->d_name.name);
809 ino = autofs4_init_ino(ino, sbi, S_IFDIR | 0555);
813 autofs4_del_active(dentry);
815 inode = autofs4_get_inode(dir->i_sb, ino);
817 if (!dentry->d_fsdata)
821 d_add(dentry, inode);
823 if (dir == dir->i_sb->s_root->d_inode)
824 dentry->d_op = &autofs4_root_dentry_operations;
826 dentry->d_op = &autofs4_dentry_operations;
828 dentry->d_fsdata = ino;
829 ino->dentry = dget(dentry);
830 atomic_inc(&ino->count);
831 p_ino = autofs4_dentry_ino(dentry->d_parent);
832 if (p_ino && dentry->d_parent != dentry)
833 atomic_inc(&p_ino->count);
836 dir->i_mtime = CURRENT_TIME;
841 /* Get/set timeout ioctl() operation */
842 static inline int autofs4_get_set_timeout(struct autofs_sb_info *sbi,
843 unsigned long __user *p)
846 unsigned long ntimeout;
848 if ((rv = get_user(ntimeout, p)) ||
849 (rv = put_user(sbi->exp_timeout/HZ, p)))
852 if (ntimeout > ULONG_MAX/HZ)
853 sbi->exp_timeout = 0;
855 sbi->exp_timeout = ntimeout * HZ;
860 /* Return protocol version */
861 static inline int autofs4_get_protover(struct autofs_sb_info *sbi, int __user *p)
863 return put_user(sbi->version, p);
866 /* Return protocol sub version */
867 static inline int autofs4_get_protosubver(struct autofs_sb_info *sbi, int __user *p)
869 return put_user(sbi->sub_version, p);
873 * Tells the daemon whether it can umount the autofs mount.
875 static inline int autofs4_ask_umount(struct vfsmount *mnt, int __user *p)
882 DPRINTK("returning %d", status);
884 status = put_user(status, p);
889 /* Identify autofs4_dentries - this is so we can tell if there's
890 an extra dentry refcount or not. We only hold a refcount on the
891 dentry if its non-negative (ie, d_inode != NULL)
893 int is_autofs4_dentry(struct dentry *dentry)
895 return dentry && dentry->d_inode &&
896 (dentry->d_op == &autofs4_root_dentry_operations ||
897 dentry->d_op == &autofs4_dentry_operations) &&
898 dentry->d_fsdata != NULL;
902 * ioctl()'s on the root directory is the chief method for the daemon to
903 * generate kernel reactions
905 static int autofs4_root_ioctl(struct inode *inode, struct file *filp,
906 unsigned int cmd, unsigned long arg)
908 struct autofs_sb_info *sbi = autofs4_sbi(inode->i_sb);
909 void __user *p = (void __user *)arg;
911 DPRINTK("cmd = 0x%08x, arg = 0x%08lx, sbi = %p, pgrp = %u",
912 cmd,arg,sbi,task_pgrp_nr(current));
914 if (_IOC_TYPE(cmd) != _IOC_TYPE(AUTOFS_IOC_FIRST) ||
915 _IOC_NR(cmd) - _IOC_NR(AUTOFS_IOC_FIRST) >= AUTOFS_IOC_COUNT)
918 if (!autofs4_oz_mode(sbi) && !capable(CAP_SYS_ADMIN))
922 case AUTOFS_IOC_READY: /* Wait queue: go ahead and retry */
923 return autofs4_wait_release(sbi,(autofs_wqt_t)arg,0);
924 case AUTOFS_IOC_FAIL: /* Wait queue: fail with ENOENT */
925 return autofs4_wait_release(sbi,(autofs_wqt_t)arg,-ENOENT);
926 case AUTOFS_IOC_CATATONIC: /* Enter catatonic mode (daemon shutdown) */
927 autofs4_catatonic_mode(sbi);
929 case AUTOFS_IOC_PROTOVER: /* Get protocol version */
930 return autofs4_get_protover(sbi, p);
931 case AUTOFS_IOC_PROTOSUBVER: /* Get protocol sub version */
932 return autofs4_get_protosubver(sbi, p);
933 case AUTOFS_IOC_SETTIMEOUT:
934 return autofs4_get_set_timeout(sbi, p);
936 case AUTOFS_IOC_ASKUMOUNT:
937 return autofs4_ask_umount(filp->f_path.mnt, p);
939 /* return a single thing to expire */
940 case AUTOFS_IOC_EXPIRE:
941 return autofs4_expire_run(inode->i_sb,filp->f_path.mnt,sbi, p);
942 /* same as above, but can send multiple expires through pipe */
943 case AUTOFS_IOC_EXPIRE_MULTI:
944 return autofs4_expire_multi(inode->i_sb,filp->f_path.mnt,sbi, p);