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(&dentry->d_lock);
170 dentry->d_flags &= ~DCACHE_AUTOFS_PENDING;
171 spin_unlock(&dentry->d_lock);
174 /* Return a negative dentry, but leave it "pending" */
177 /* Trigger mount for path component or follow link */
178 } else if (dentry->d_flags & DCACHE_AUTOFS_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(&dentry->d_lock);
185 dentry->d_flags |= DCACHE_AUTOFS_PENDING;
186 spin_unlock(&dentry->d_lock);
187 status = autofs4_wait(sbi, dentry, NFY_MOUNT);
189 DPRINTK("mount done status=%d", status);
192 spin_lock(&dentry->d_lock);
193 dentry->d_flags &= ~DCACHE_AUTOFS_PENDING;
194 spin_unlock(&dentry->d_lock);
199 /* Initialize expiry counter after successful mount */
201 ino->last_used = jiffies;
203 spin_lock(&dentry->d_lock);
204 dentry->d_flags &= ~DCACHE_AUTOFS_PENDING;
205 spin_unlock(&dentry->d_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 if (!(lookup_type || dentry->d_flags & DCACHE_AUTOFS_PENDING))
250 * If the dentry contains directories then it is an autofs
251 * multi-mount with no root mount offset. So don't try to
254 spin_lock(&dcache_lock);
255 if (dentry->d_flags & DCACHE_AUTOFS_PENDING ||
256 (!d_mountpoint(dentry) && __simple_empty(dentry))) {
257 spin_unlock(&dcache_lock);
259 status = try_to_fill_dentry(dentry, 0);
265 spin_unlock(&dcache_lock);
268 * If there is no root mount it must be an autofs
269 * multi-mount with no root offset so we don't need
272 if (d_mountpoint(dentry)) {
273 if (!autofs4_follow_mount(&nd->path)) {
284 return ERR_PTR(status);
288 * Revalidate is called on every cache lookup. Some of those
289 * cache lookups may actually happen while the dentry is not
290 * yet completely filled in, and revalidate has to delay such
293 static int autofs4_revalidate(struct dentry *dentry, struct nameidata *nd)
295 struct inode *dir = dentry->d_parent->d_inode;
296 struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb);
297 int oz_mode = autofs4_oz_mode(sbi);
298 int flags = nd ? nd->flags : 0;
302 spin_lock(&sbi->fs_lock);
303 if (autofs4_ispending(dentry)) {
304 /* The daemon never causes a mount to trigger */
305 spin_unlock(&sbi->fs_lock);
311 * If the directory has gone away due to an expire
312 * we have been called as ->d_revalidate() and so
313 * we need to return false and proceed to ->lookup().
315 if (autofs4_expire_wait(dentry) == -EAGAIN)
319 * A zero status is success otherwise we have a
320 * negative error code.
322 status = try_to_fill_dentry(dentry, flags);
328 spin_unlock(&sbi->fs_lock);
330 /* Negative dentry.. invalidate if "old" */
331 if (dentry->d_inode == NULL)
334 /* Check for a non-mountpoint directory with no contents */
335 spin_lock(&dcache_lock);
336 if (S_ISDIR(dentry->d_inode->i_mode) &&
337 !d_mountpoint(dentry) &&
338 __simple_empty(dentry)) {
339 DPRINTK("dentry=%p %.*s, emptydir",
340 dentry, dentry->d_name.len, dentry->d_name.name);
341 spin_unlock(&dcache_lock);
343 /* The daemon never causes a mount to trigger */
348 * A zero status is success otherwise we have a
349 * negative error code.
351 status = try_to_fill_dentry(dentry, flags);
357 spin_unlock(&dcache_lock);
362 void autofs4_dentry_release(struct dentry *de)
364 struct autofs_info *inf;
366 DPRINTK("releasing %p", de);
368 inf = autofs4_dentry_ino(de);
372 struct autofs_sb_info *sbi = autofs4_sbi(de->d_sb);
375 spin_lock(&sbi->lookup_lock);
376 if (!list_empty(&inf->active))
377 list_del(&inf->active);
378 if (!list_empty(&inf->expiring))
379 list_del(&inf->expiring);
380 spin_unlock(&sbi->lookup_lock);
386 autofs4_free_ino(inf);
390 /* For dentries of directories in the root dir */
391 static const struct dentry_operations autofs4_root_dentry_operations = {
392 .d_revalidate = autofs4_revalidate,
393 .d_release = autofs4_dentry_release,
396 /* For other dentries */
397 static const struct dentry_operations autofs4_dentry_operations = {
398 .d_revalidate = autofs4_revalidate,
399 .d_release = autofs4_dentry_release,
402 static struct dentry *autofs4_lookup_active(struct autofs_sb_info *sbi, struct dentry *parent, struct qstr *name)
404 unsigned int len = name->len;
405 unsigned int hash = name->hash;
406 const unsigned char *str = name->name;
407 struct list_head *p, *head;
409 spin_lock(&dcache_lock);
410 spin_lock(&sbi->lookup_lock);
411 head = &sbi->active_list;
412 list_for_each(p, head) {
413 struct autofs_info *ino;
414 struct dentry *dentry;
417 ino = list_entry(p, struct autofs_info, active);
418 dentry = ino->dentry;
420 spin_lock(&dentry->d_lock);
423 if (atomic_read(&dentry->d_count) == 0)
426 qstr = &dentry->d_name;
428 if (dentry->d_name.hash != hash)
430 if (dentry->d_parent != parent)
433 if (qstr->len != len)
435 if (memcmp(qstr->name, str, len))
438 if (d_unhashed(dentry)) {
440 spin_unlock(&dentry->d_lock);
441 spin_unlock(&sbi->lookup_lock);
442 spin_unlock(&dcache_lock);
446 spin_unlock(&dentry->d_lock);
448 spin_unlock(&sbi->lookup_lock);
449 spin_unlock(&dcache_lock);
454 static struct dentry *autofs4_lookup_expiring(struct autofs_sb_info *sbi, struct dentry *parent, struct qstr *name)
456 unsigned int len = name->len;
457 unsigned int hash = name->hash;
458 const unsigned char *str = name->name;
459 struct list_head *p, *head;
461 spin_lock(&dcache_lock);
462 spin_lock(&sbi->lookup_lock);
463 head = &sbi->expiring_list;
464 list_for_each(p, head) {
465 struct autofs_info *ino;
466 struct dentry *dentry;
469 ino = list_entry(p, struct autofs_info, expiring);
470 dentry = ino->dentry;
472 spin_lock(&dentry->d_lock);
474 /* Bad luck, we've already been dentry_iput */
475 if (!dentry->d_inode)
478 qstr = &dentry->d_name;
480 if (dentry->d_name.hash != hash)
482 if (dentry->d_parent != parent)
485 if (qstr->len != len)
487 if (memcmp(qstr->name, str, len))
490 if (d_unhashed(dentry)) {
492 spin_unlock(&dentry->d_lock);
493 spin_unlock(&sbi->lookup_lock);
494 spin_unlock(&dcache_lock);
498 spin_unlock(&dentry->d_lock);
500 spin_unlock(&sbi->lookup_lock);
501 spin_unlock(&dcache_lock);
506 /* Lookups in the root directory */
507 static struct dentry *autofs4_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd)
509 struct autofs_sb_info *sbi;
510 struct autofs_info *ino;
511 struct dentry *expiring, *unhashed;
514 DPRINTK("name = %.*s",
515 dentry->d_name.len, dentry->d_name.name);
517 /* File name too long to exist */
518 if (dentry->d_name.len > NAME_MAX)
519 return ERR_PTR(-ENAMETOOLONG);
521 sbi = autofs4_sbi(dir->i_sb);
522 oz_mode = autofs4_oz_mode(sbi);
524 DPRINTK("pid = %u, pgrp = %u, catatonic = %d, oz_mode = %d",
525 current->pid, task_pgrp_nr(current), sbi->catatonic, oz_mode);
527 unhashed = autofs4_lookup_active(sbi, dentry->d_parent, &dentry->d_name);
532 * Mark the dentry incomplete but don't hash it. We do this
533 * to serialize our inode creation operations (symlink and
534 * mkdir) which prevents deadlock during the callback to
535 * the daemon. Subsequent user space lookups for the same
536 * dentry are placed on the wait queue while the daemon
537 * itself is allowed passage unresticted so the create
538 * operation itself can then hash the dentry. Finally,
539 * we check for the hashed dentry and return the newly
542 dentry->d_op = &autofs4_root_dentry_operations;
545 * And we need to ensure that the same dentry is used for
546 * all following lookup calls until it is hashed so that
547 * the dentry flags are persistent throughout the request.
549 ino = autofs4_init_ino(NULL, sbi, 0555);
551 return ERR_PTR(-ENOMEM);
553 dentry->d_fsdata = ino;
554 ino->dentry = dentry;
556 autofs4_add_active(dentry);
558 d_instantiate(dentry, NULL);
562 mutex_unlock(&dir->i_mutex);
563 expiring = autofs4_lookup_expiring(sbi,
568 * If we are racing with expire the request might not
569 * be quite complete but the directory has been removed
570 * so it must have been successful, so just wait for it.
572 ino = autofs4_dentry_ino(expiring);
573 autofs4_expire_wait(expiring);
574 autofs4_del_expiring(expiring);
578 spin_lock(&dentry->d_lock);
579 dentry->d_flags |= DCACHE_AUTOFS_PENDING;
580 spin_unlock(&dentry->d_lock);
581 if (dentry->d_op && dentry->d_op->d_revalidate)
582 (dentry->d_op->d_revalidate)(dentry, nd);
583 mutex_lock(&dir->i_mutex);
587 * If we are still pending, check if we had to handle
588 * a signal. If so we can force a restart..
590 if (dentry->d_flags & DCACHE_AUTOFS_PENDING) {
591 /* See if we were interrupted */
592 if (signal_pending(current)) {
593 sigset_t *sigset = ¤t->pending.signal;
594 if (sigismember (sigset, SIGKILL) ||
595 sigismember (sigset, SIGQUIT) ||
596 sigismember (sigset, SIGINT)) {
599 return ERR_PTR(-ERESTARTNOINTR);
603 spin_lock(&dentry->d_lock);
604 dentry->d_flags &= ~DCACHE_AUTOFS_PENDING;
605 spin_unlock(&dentry->d_lock);
610 * If this dentry is unhashed, then we shouldn't honour this
611 * lookup. Returning ENOENT here doesn't do the right thing
612 * for all system calls, but it should be OK for the operations
613 * we permit from an autofs.
615 if (!oz_mode && d_unhashed(dentry)) {
617 * A user space application can (and has done in the past)
618 * remove and re-create this directory during the callback.
619 * This can leave us with an unhashed dentry, but a
620 * successful mount! So we need to perform another
621 * cached lookup in case the dentry now exists.
623 struct dentry *parent = dentry->d_parent;
624 struct dentry *new = d_lookup(parent, &dentry->d_name);
628 dentry = ERR_PTR(-ENOENT);
642 static int autofs4_dir_symlink(struct inode *dir,
643 struct dentry *dentry,
646 struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb);
647 struct autofs_info *ino = autofs4_dentry_ino(dentry);
648 struct autofs_info *p_ino;
652 DPRINTK("%s <- %.*s", symname,
653 dentry->d_name.len, dentry->d_name.name);
655 if (!autofs4_oz_mode(sbi))
658 ino = autofs4_init_ino(ino, sbi, S_IFLNK | 0555);
662 autofs4_del_active(dentry);
664 ino->size = strlen(symname);
665 cp = kmalloc(ino->size + 1, GFP_KERNEL);
667 if (!dentry->d_fsdata)
674 inode = autofs4_get_inode(dir->i_sb, ino);
677 if (!dentry->d_fsdata)
681 d_add(dentry, inode);
683 if (dir == dir->i_sb->s_root->d_inode)
684 dentry->d_op = &autofs4_root_dentry_operations;
686 dentry->d_op = &autofs4_dentry_operations;
688 dentry->d_fsdata = ino;
689 ino->dentry = dget(dentry);
690 atomic_inc(&ino->count);
691 p_ino = autofs4_dentry_ino(dentry->d_parent);
692 if (p_ino && dentry->d_parent != dentry)
693 atomic_inc(&p_ino->count);
697 dir->i_mtime = CURRENT_TIME;
705 * Normal filesystems would do a "d_delete()" to tell the VFS dcache
706 * that the file no longer exists. However, doing that means that the
707 * VFS layer can turn the dentry into a negative dentry. We don't want
708 * this, because the unlink is probably the result of an expire.
709 * We simply d_drop it and add it to a expiring list in the super block,
710 * which allows the dentry lookup to check for an incomplete expire.
712 * If a process is blocked on the dentry waiting for the expire to finish,
713 * it will invalidate the dentry and try to mount with a new one.
715 * Also see autofs4_dir_rmdir()..
717 static int autofs4_dir_unlink(struct inode *dir, struct dentry *dentry)
719 struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb);
720 struct autofs_info *ino = autofs4_dentry_ino(dentry);
721 struct autofs_info *p_ino;
723 /* This allows root to remove symlinks */
724 if (!autofs4_oz_mode(sbi) && !capable(CAP_SYS_ADMIN))
727 if (atomic_dec_and_test(&ino->count)) {
728 p_ino = autofs4_dentry_ino(dentry->d_parent);
729 if (p_ino && dentry->d_parent != dentry)
730 atomic_dec(&p_ino->count);
734 dentry->d_inode->i_size = 0;
735 clear_nlink(dentry->d_inode);
737 dir->i_mtime = CURRENT_TIME;
739 spin_lock(&dcache_lock);
740 autofs4_add_expiring(dentry);
741 spin_lock(&dentry->d_lock);
743 spin_unlock(&dentry->d_lock);
744 spin_unlock(&dcache_lock);
749 static int autofs4_dir_rmdir(struct inode *dir, struct dentry *dentry)
751 struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb);
752 struct autofs_info *ino = autofs4_dentry_ino(dentry);
753 struct autofs_info *p_ino;
755 DPRINTK("dentry %p, removing %.*s",
756 dentry, dentry->d_name.len, dentry->d_name.name);
758 if (!autofs4_oz_mode(sbi))
761 spin_lock(&dcache_lock);
762 if (!list_empty(&dentry->d_subdirs)) {
763 spin_unlock(&dcache_lock);
766 autofs4_add_expiring(dentry);
767 spin_lock(&dentry->d_lock);
769 spin_unlock(&dentry->d_lock);
770 spin_unlock(&dcache_lock);
772 if (atomic_dec_and_test(&ino->count)) {
773 p_ino = autofs4_dentry_ino(dentry->d_parent);
774 if (p_ino && dentry->d_parent != dentry)
775 atomic_dec(&p_ino->count);
778 dentry->d_inode->i_size = 0;
779 clear_nlink(dentry->d_inode);
787 static int autofs4_dir_mkdir(struct inode *dir, struct dentry *dentry, int mode)
789 struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb);
790 struct autofs_info *ino = autofs4_dentry_ino(dentry);
791 struct autofs_info *p_ino;
794 if (!autofs4_oz_mode(sbi))
797 DPRINTK("dentry %p, creating %.*s",
798 dentry, dentry->d_name.len, dentry->d_name.name);
800 ino = autofs4_init_ino(ino, sbi, S_IFDIR | 0555);
804 autofs4_del_active(dentry);
806 inode = autofs4_get_inode(dir->i_sb, ino);
808 if (!dentry->d_fsdata)
812 d_add(dentry, inode);
814 if (dir == dir->i_sb->s_root->d_inode)
815 dentry->d_op = &autofs4_root_dentry_operations;
817 dentry->d_op = &autofs4_dentry_operations;
819 dentry->d_fsdata = ino;
820 ino->dentry = dget(dentry);
821 atomic_inc(&ino->count);
822 p_ino = autofs4_dentry_ino(dentry->d_parent);
823 if (p_ino && dentry->d_parent != dentry)
824 atomic_inc(&p_ino->count);
827 dir->i_mtime = CURRENT_TIME;
832 /* Get/set timeout ioctl() operation */
833 static inline int autofs4_get_set_timeout(struct autofs_sb_info *sbi,
834 unsigned long __user *p)
837 unsigned long ntimeout;
839 if ((rv = get_user(ntimeout, p)) ||
840 (rv = put_user(sbi->exp_timeout/HZ, p)))
843 if (ntimeout > ULONG_MAX/HZ)
844 sbi->exp_timeout = 0;
846 sbi->exp_timeout = ntimeout * HZ;
851 /* Return protocol version */
852 static inline int autofs4_get_protover(struct autofs_sb_info *sbi, int __user *p)
854 return put_user(sbi->version, p);
857 /* Return protocol sub version */
858 static inline int autofs4_get_protosubver(struct autofs_sb_info *sbi, int __user *p)
860 return put_user(sbi->sub_version, p);
864 * Tells the daemon whether it can umount the autofs mount.
866 static inline int autofs4_ask_umount(struct vfsmount *mnt, int __user *p)
873 DPRINTK("returning %d", status);
875 status = put_user(status, p);
880 /* Identify autofs4_dentries - this is so we can tell if there's
881 an extra dentry refcount or not. We only hold a refcount on the
882 dentry if its non-negative (ie, d_inode != NULL)
884 int is_autofs4_dentry(struct dentry *dentry)
886 return dentry && dentry->d_inode &&
887 (dentry->d_op == &autofs4_root_dentry_operations ||
888 dentry->d_op == &autofs4_dentry_operations) &&
889 dentry->d_fsdata != NULL;
893 * ioctl()'s on the root directory is the chief method for the daemon to
894 * generate kernel reactions
896 static int autofs4_root_ioctl(struct inode *inode, struct file *filp,
897 unsigned int cmd, unsigned long arg)
899 struct autofs_sb_info *sbi = autofs4_sbi(inode->i_sb);
900 void __user *p = (void __user *)arg;
902 DPRINTK("cmd = 0x%08x, arg = 0x%08lx, sbi = %p, pgrp = %u",
903 cmd,arg,sbi,task_pgrp_nr(current));
905 if (_IOC_TYPE(cmd) != _IOC_TYPE(AUTOFS_IOC_FIRST) ||
906 _IOC_NR(cmd) - _IOC_NR(AUTOFS_IOC_FIRST) >= AUTOFS_IOC_COUNT)
909 if (!autofs4_oz_mode(sbi) && !capable(CAP_SYS_ADMIN))
913 case AUTOFS_IOC_READY: /* Wait queue: go ahead and retry */
914 return autofs4_wait_release(sbi,(autofs_wqt_t)arg,0);
915 case AUTOFS_IOC_FAIL: /* Wait queue: fail with ENOENT */
916 return autofs4_wait_release(sbi,(autofs_wqt_t)arg,-ENOENT);
917 case AUTOFS_IOC_CATATONIC: /* Enter catatonic mode (daemon shutdown) */
918 autofs4_catatonic_mode(sbi);
920 case AUTOFS_IOC_PROTOVER: /* Get protocol version */
921 return autofs4_get_protover(sbi, p);
922 case AUTOFS_IOC_PROTOSUBVER: /* Get protocol sub version */
923 return autofs4_get_protosubver(sbi, p);
924 case AUTOFS_IOC_SETTIMEOUT:
925 return autofs4_get_set_timeout(sbi, p);
927 case AUTOFS_IOC_ASKUMOUNT:
928 return autofs4_ask_umount(filp->f_path.mnt, p);
930 /* return a single thing to expire */
931 case AUTOFS_IOC_EXPIRE:
932 return autofs4_expire_run(inode->i_sb,filp->f_path.mnt,sbi, p);
933 /* same as above, but can send multiple expires through pipe */
934 case AUTOFS_IOC_EXPIRE_MULTI:
935 return autofs4_expire_multi(inode->i_sb,filp->f_path.mnt,sbi, p);