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 int autofs4_dir_close(struct inode
*inode
, struct file
*file
);
29 static int autofs4_dir_readdir(struct file
* filp
, void * dirent
, filldir_t filldir
);
30 static int autofs4_root_readdir(struct file
* filp
, void * dirent
, filldir_t filldir
);
31 static struct dentry
*autofs4_lookup(struct inode
*,struct dentry
*, struct nameidata
*);
32 static void *autofs4_follow_link(struct dentry
*, struct nameidata
*);
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
= autofs4_root_readdir
,
39 .ioctl
= autofs4_root_ioctl
,
42 const struct file_operations autofs4_dir_operations
= {
43 .open
= autofs4_dir_open
,
44 .release
= autofs4_dir_close
,
45 .read
= generic_read_dir
,
46 .readdir
= autofs4_dir_readdir
,
49 const struct inode_operations autofs4_indirect_root_inode_operations
= {
50 .lookup
= autofs4_lookup
,
51 .unlink
= autofs4_dir_unlink
,
52 .symlink
= autofs4_dir_symlink
,
53 .mkdir
= autofs4_dir_mkdir
,
54 .rmdir
= autofs4_dir_rmdir
,
57 const struct inode_operations autofs4_direct_root_inode_operations
= {
58 .lookup
= autofs4_lookup
,
59 .unlink
= autofs4_dir_unlink
,
60 .mkdir
= autofs4_dir_mkdir
,
61 .rmdir
= autofs4_dir_rmdir
,
62 .follow_link
= autofs4_follow_link
,
65 const struct inode_operations autofs4_dir_inode_operations
= {
66 .lookup
= autofs4_lookup
,
67 .unlink
= autofs4_dir_unlink
,
68 .symlink
= autofs4_dir_symlink
,
69 .mkdir
= autofs4_dir_mkdir
,
70 .rmdir
= autofs4_dir_rmdir
,
73 static int autofs4_root_readdir(struct file
*file
, void *dirent
,
76 struct autofs_sb_info
*sbi
= autofs4_sbi(file
->f_path
.dentry
->d_sb
);
77 int oz_mode
= autofs4_oz_mode(sbi
);
79 DPRINTK("called, filp->f_pos = %lld", file
->f_pos
);
82 * Don't set reghost flag if:
83 * 1) f_pos is larger than zero -- we've already been here.
84 * 2) we haven't even enabled reghosting in the 1st place.
85 * 3) this is the daemon doing a readdir
87 if (oz_mode
&& file
->f_pos
== 0 && sbi
->reghost_enabled
)
88 sbi
->needs_reghost
= 1;
90 DPRINTK("needs_reghost = %d", sbi
->needs_reghost
);
92 return dcache_readdir(file
, dirent
, filldir
);
95 static int autofs4_dir_open(struct inode
*inode
, struct file
*file
)
97 struct dentry
*dentry
= file
->f_path
.dentry
;
98 struct vfsmount
*mnt
= file
->f_path
.mnt
;
99 struct autofs_sb_info
*sbi
= autofs4_sbi(dentry
->d_sb
);
100 struct dentry
*cursor
;
103 status
= dcache_dir_open(inode
, file
);
107 cursor
= file
->private_data
;
108 cursor
->d_fsdata
= NULL
;
110 DPRINTK("file=%p dentry=%p %.*s",
111 file
, dentry
, dentry
->d_name
.len
, dentry
->d_name
.name
);
113 if (autofs4_oz_mode(sbi
))
116 if (autofs4_ispending(dentry
)) {
117 DPRINTK("dentry busy");
118 dcache_dir_close(inode
, file
);
124 if (!d_mountpoint(dentry
) && dentry
->d_op
&& dentry
->d_op
->d_revalidate
) {
128 /* In case there are stale directory dentrys from a failed mount */
129 spin_lock(&dcache_lock
);
130 empty
= list_empty(&dentry
->d_subdirs
);
131 spin_unlock(&dcache_lock
);
134 d_invalidate(dentry
);
136 nd
.flags
= LOOKUP_DIRECTORY
;
137 ret
= (dentry
->d_op
->d_revalidate
)(dentry
, &nd
);
142 dcache_dir_close(inode
, file
);
147 if (d_mountpoint(dentry
)) {
148 struct file
*fp
= NULL
;
149 struct path fp_path
= { .dentry
= dentry
, .mnt
= mnt
};
153 if (!autofs4_follow_mount(&fp_path
.mnt
, &fp_path
.dentry
)) {
155 dcache_dir_close(inode
, file
);
159 fp
= dentry_open(fp_path
.dentry
, fp_path
.mnt
, file
->f_flags
);
160 status
= PTR_ERR(fp
);
162 dcache_dir_close(inode
, file
);
165 cursor
->d_fsdata
= fp
;
172 static int autofs4_dir_close(struct inode
*inode
, struct file
*file
)
174 struct dentry
*dentry
= file
->f_path
.dentry
;
175 struct autofs_sb_info
*sbi
= autofs4_sbi(dentry
->d_sb
);
176 struct dentry
*cursor
= file
->private_data
;
179 DPRINTK("file=%p dentry=%p %.*s",
180 file
, dentry
, dentry
->d_name
.len
, dentry
->d_name
.name
);
182 if (autofs4_oz_mode(sbi
))
185 if (autofs4_ispending(dentry
)) {
186 DPRINTK("dentry busy");
191 if (d_mountpoint(dentry
)) {
192 struct file
*fp
= cursor
->d_fsdata
;
197 filp_close(fp
, current
->files
);
200 dcache_dir_close(inode
, file
);
204 static int autofs4_dir_readdir(struct file
*file
, void *dirent
, filldir_t filldir
)
206 struct dentry
*dentry
= file
->f_path
.dentry
;
207 struct autofs_sb_info
*sbi
= autofs4_sbi(dentry
->d_sb
);
208 struct dentry
*cursor
= file
->private_data
;
211 DPRINTK("file=%p dentry=%p %.*s",
212 file
, dentry
, dentry
->d_name
.len
, dentry
->d_name
.name
);
214 if (autofs4_oz_mode(sbi
))
217 if (autofs4_ispending(dentry
)) {
218 DPRINTK("dentry busy");
222 if (d_mountpoint(dentry
)) {
223 struct file
*fp
= cursor
->d_fsdata
;
228 if (!fp
->f_op
|| !fp
->f_op
->readdir
)
231 status
= vfs_readdir(fp
, filldir
, dirent
);
232 file
->f_pos
= fp
->f_pos
;
234 autofs4_copy_atime(file
, fp
);
238 return dcache_readdir(file
, dirent
, filldir
);
241 static int try_to_fill_dentry(struct dentry
*dentry
, int flags
)
243 struct autofs_sb_info
*sbi
= autofs4_sbi(dentry
->d_sb
);
244 struct autofs_info
*ino
= autofs4_dentry_ino(dentry
);
247 /* Block on any pending expiry here; invalidate the dentry
248 when expiration is done to trigger mount request with a new
250 if (ino
&& (ino
->flags
& AUTOFS_INF_EXPIRING
)) {
251 DPRINTK("waiting for expire %p name=%.*s",
252 dentry
, dentry
->d_name
.len
, dentry
->d_name
.name
);
254 status
= autofs4_wait(sbi
, dentry
, NFY_NONE
);
256 DPRINTK("expire done status=%d", status
);
259 * If the directory still exists the mount request must
260 * continue otherwise it can't be followed at the right
261 * time during the walk.
263 status
= d_invalidate(dentry
);
264 if (status
!= -EBUSY
)
268 DPRINTK("dentry=%p %.*s ino=%p",
269 dentry
, dentry
->d_name
.len
, dentry
->d_name
.name
, dentry
->d_inode
);
272 * Wait for a pending mount, triggering one if there
275 if (dentry
->d_inode
== NULL
) {
276 DPRINTK("waiting for mount name=%.*s",
277 dentry
->d_name
.len
, dentry
->d_name
.name
);
279 status
= autofs4_wait(sbi
, dentry
, NFY_MOUNT
);
281 DPRINTK("mount done status=%d", status
);
283 /* Turn this into a real negative dentry? */
284 if (status
== -ENOENT
) {
285 spin_lock(&dentry
->d_lock
);
286 dentry
->d_flags
&= ~DCACHE_AUTOFS_PENDING
;
287 spin_unlock(&dentry
->d_lock
);
290 /* Return a negative dentry, but leave it "pending" */
293 /* Trigger mount for path component or follow link */
294 } else if (flags
& (LOOKUP_CONTINUE
| LOOKUP_DIRECTORY
) ||
295 current
->link_count
) {
296 DPRINTK("waiting for mount name=%.*s",
297 dentry
->d_name
.len
, dentry
->d_name
.name
);
299 spin_lock(&dentry
->d_lock
);
300 dentry
->d_flags
|= DCACHE_AUTOFS_PENDING
;
301 spin_unlock(&dentry
->d_lock
);
302 status
= autofs4_wait(sbi
, dentry
, NFY_MOUNT
);
304 DPRINTK("mount done status=%d", status
);
307 spin_lock(&dentry
->d_lock
);
308 dentry
->d_flags
&= ~DCACHE_AUTOFS_PENDING
;
309 spin_unlock(&dentry
->d_lock
);
314 /* Initialize expiry counter after successful mount */
316 ino
->last_used
= jiffies
;
318 spin_lock(&dentry
->d_lock
);
319 dentry
->d_flags
&= ~DCACHE_AUTOFS_PENDING
;
320 spin_unlock(&dentry
->d_lock
);
325 /* For autofs direct mounts the follow link triggers the mount */
326 static void *autofs4_follow_link(struct dentry
*dentry
, struct nameidata
*nd
)
328 struct autofs_sb_info
*sbi
= autofs4_sbi(dentry
->d_sb
);
329 struct autofs_info
*ino
= autofs4_dentry_ino(dentry
);
330 int oz_mode
= autofs4_oz_mode(sbi
);
331 unsigned int lookup_type
;
334 DPRINTK("dentry=%p %.*s oz_mode=%d nd->flags=%d",
335 dentry
, dentry
->d_name
.len
, dentry
->d_name
.name
, oz_mode
,
338 /* If it's our master or we shouldn't trigger a mount we're done */
339 lookup_type
= nd
->flags
& (LOOKUP_CONTINUE
| LOOKUP_DIRECTORY
);
340 if (oz_mode
|| !lookup_type
)
343 /* If an expire request is pending wait for it. */
344 if (ino
&& (ino
->flags
& AUTOFS_INF_EXPIRING
)) {
345 DPRINTK("waiting for active request %p name=%.*s",
346 dentry
, dentry
->d_name
.len
, dentry
->d_name
.name
);
348 status
= autofs4_wait(sbi
, dentry
, NFY_NONE
);
350 DPRINTK("request done status=%d", status
);
354 * If the dentry contains directories then it is an
355 * autofs multi-mount with no root mount offset. So
356 * don't try to mount it again.
358 spin_lock(&dcache_lock
);
359 if (!d_mountpoint(dentry
) && __simple_empty(dentry
)) {
360 spin_unlock(&dcache_lock
);
362 status
= try_to_fill_dentry(dentry
, 0);
367 * The mount succeeded but if there is no root mount
368 * it must be an autofs multi-mount with no root offset
369 * so we don't need to follow the mount.
371 if (d_mountpoint(dentry
)) {
372 if (!autofs4_follow_mount(&nd
->path
.mnt
,
381 spin_unlock(&dcache_lock
);
388 return ERR_PTR(status
);
392 * Revalidate is called on every cache lookup. Some of those
393 * cache lookups may actually happen while the dentry is not
394 * yet completely filled in, and revalidate has to delay such
397 static int autofs4_revalidate(struct dentry
*dentry
, struct nameidata
*nd
)
399 struct inode
*dir
= dentry
->d_parent
->d_inode
;
400 struct autofs_sb_info
*sbi
= autofs4_sbi(dir
->i_sb
);
401 int oz_mode
= autofs4_oz_mode(sbi
);
402 int flags
= nd
? nd
->flags
: 0;
406 if (autofs4_ispending(dentry
)) {
407 /* The daemon never causes a mount to trigger */
412 * A zero status is success otherwise we have a
413 * negative error code.
415 status
= try_to_fill_dentry(dentry
, flags
);
420 * A status of EAGAIN here means that the dentry has gone
421 * away while waiting for an expire to complete. If we are
422 * racing with expire lookup will wait for it so this must
423 * be a revalidate and we need to send it to lookup.
425 if (status
== -EAGAIN
)
431 /* Negative dentry.. invalidate if "old" */
432 if (dentry
->d_inode
== NULL
)
435 /* Check for a non-mountpoint directory with no contents */
436 spin_lock(&dcache_lock
);
437 if (S_ISDIR(dentry
->d_inode
->i_mode
) &&
438 !d_mountpoint(dentry
) &&
439 __simple_empty(dentry
)) {
440 DPRINTK("dentry=%p %.*s, emptydir",
441 dentry
, dentry
->d_name
.len
, dentry
->d_name
.name
);
442 spin_unlock(&dcache_lock
);
443 /* The daemon never causes a mount to trigger */
448 * A zero status is success otherwise we have a
449 * negative error code.
451 status
= try_to_fill_dentry(dentry
, flags
);
457 spin_unlock(&dcache_lock
);
462 void autofs4_dentry_release(struct dentry
*de
)
464 struct autofs_info
*inf
;
466 DPRINTK("releasing %p", de
);
468 inf
= autofs4_dentry_ino(de
);
472 struct autofs_sb_info
*sbi
= autofs4_sbi(de
->d_sb
);
475 spin_lock(&sbi
->lookup_lock
);
476 if (!list_empty(&inf
->active
))
477 list_del(&inf
->active
);
478 if (!list_empty(&inf
->expiring
))
479 list_del(&inf
->expiring
);
480 spin_unlock(&sbi
->lookup_lock
);
486 autofs4_free_ino(inf
);
490 /* For dentries of directories in the root dir */
491 static struct dentry_operations autofs4_root_dentry_operations
= {
492 .d_revalidate
= autofs4_revalidate
,
493 .d_release
= autofs4_dentry_release
,
496 /* For other dentries */
497 static struct dentry_operations autofs4_dentry_operations
= {
498 .d_revalidate
= autofs4_revalidate
,
499 .d_release
= autofs4_dentry_release
,
502 static struct dentry
*autofs4_lookup_active(struct autofs_sb_info
*sbi
, struct dentry
*parent
, struct qstr
*name
)
504 unsigned int len
= name
->len
;
505 unsigned int hash
= name
->hash
;
506 const unsigned char *str
= name
->name
;
507 struct list_head
*p
, *head
;
509 spin_lock(&dcache_lock
);
510 spin_lock(&sbi
->lookup_lock
);
511 head
= &sbi
->active_list
;
512 list_for_each(p
, head
) {
513 struct autofs_info
*ino
;
514 struct dentry
*dentry
;
517 ino
= list_entry(p
, struct autofs_info
, active
);
518 dentry
= ino
->dentry
;
520 spin_lock(&dentry
->d_lock
);
523 if (atomic_read(&dentry
->d_count
) == 0)
526 qstr
= &dentry
->d_name
;
528 if (dentry
->d_name
.hash
!= hash
)
530 if (dentry
->d_parent
!= parent
)
533 if (qstr
->len
!= len
)
535 if (memcmp(qstr
->name
, str
, len
))
538 if (d_unhashed(dentry
)) {
540 spin_unlock(&dentry
->d_lock
);
541 spin_unlock(&sbi
->lookup_lock
);
542 spin_unlock(&dcache_lock
);
546 spin_unlock(&dentry
->d_lock
);
548 spin_unlock(&sbi
->lookup_lock
);
549 spin_unlock(&dcache_lock
);
554 static struct dentry
*autofs4_lookup_expiring(struct autofs_sb_info
*sbi
, struct dentry
*parent
, struct qstr
*name
)
556 unsigned int len
= name
->len
;
557 unsigned int hash
= name
->hash
;
558 const unsigned char *str
= name
->name
;
559 struct list_head
*p
, *head
;
561 spin_lock(&dcache_lock
);
562 spin_lock(&sbi
->lookup_lock
);
563 head
= &sbi
->expiring_list
;
564 list_for_each(p
, head
) {
565 struct autofs_info
*ino
;
566 struct dentry
*dentry
;
569 ino
= list_entry(p
, struct autofs_info
, expiring
);
570 dentry
= ino
->dentry
;
572 spin_lock(&dentry
->d_lock
);
574 /* Bad luck, we've already been dentry_iput */
575 if (!dentry
->d_inode
)
578 qstr
= &dentry
->d_name
;
580 if (dentry
->d_name
.hash
!= hash
)
582 if (dentry
->d_parent
!= parent
)
585 if (qstr
->len
!= len
)
587 if (memcmp(qstr
->name
, str
, len
))
590 if (d_unhashed(dentry
)) {
592 spin_unlock(&dentry
->d_lock
);
593 spin_unlock(&sbi
->lookup_lock
);
594 spin_unlock(&dcache_lock
);
598 spin_unlock(&dentry
->d_lock
);
600 spin_unlock(&sbi
->lookup_lock
);
601 spin_unlock(&dcache_lock
);
606 /* Lookups in the root directory */
607 static struct dentry
*autofs4_lookup(struct inode
*dir
, struct dentry
*dentry
, struct nameidata
*nd
)
609 struct autofs_sb_info
*sbi
;
610 struct autofs_info
*ino
;
611 struct dentry
*expiring
, *unhashed
;
614 DPRINTK("name = %.*s",
615 dentry
->d_name
.len
, dentry
->d_name
.name
);
617 /* File name too long to exist */
618 if (dentry
->d_name
.len
> NAME_MAX
)
619 return ERR_PTR(-ENAMETOOLONG
);
621 sbi
= autofs4_sbi(dir
->i_sb
);
622 oz_mode
= autofs4_oz_mode(sbi
);
624 DPRINTK("pid = %u, pgrp = %u, catatonic = %d, oz_mode = %d",
625 current
->pid
, task_pgrp_nr(current
), sbi
->catatonic
, oz_mode
);
627 expiring
= autofs4_lookup_expiring(sbi
, dentry
->d_parent
, &dentry
->d_name
);
630 * If we are racing with expire the request might not
631 * be quite complete but the directory has been removed
632 * so it must have been successful, so just wait for it.
634 ino
= autofs4_dentry_ino(expiring
);
635 while (ino
&& (ino
->flags
& AUTOFS_INF_EXPIRING
)) {
636 DPRINTK("wait for incomplete expire %p name=%.*s",
637 expiring
, expiring
->d_name
.len
,
638 expiring
->d_name
.name
);
639 autofs4_wait(sbi
, expiring
, NFY_NONE
);
640 DPRINTK("request completed");
642 spin_lock(&sbi
->lookup_lock
);
643 if (!list_empty(&ino
->expiring
))
644 list_del_init(&ino
->expiring
);
645 spin_unlock(&sbi
->lookup_lock
);
649 unhashed
= autofs4_lookup_active(sbi
, dentry
->d_parent
, &dentry
->d_name
);
654 * Mark the dentry incomplete but don't hash it. We do this
655 * to serialize our inode creation operations (symlink and
656 * mkdir) which prevents deadlock during the callback to
657 * the daemon. Subsequent user space lookups for the same
658 * dentry are placed on the wait queue while the daemon
659 * itself is allowed passage unresticted so the create
660 * operation itself can then hash the dentry. Finally,
661 * we check for the hashed dentry and return the newly
664 dentry
->d_op
= &autofs4_root_dentry_operations
;
667 * And we need to ensure that the same dentry is used for
668 * all following lookup calls until it is hashed so that
669 * the dentry flags are persistent throughout the request.
671 ino
= autofs4_init_ino(NULL
, sbi
, 0555);
673 return ERR_PTR(-ENOMEM
);
675 dentry
->d_fsdata
= ino
;
676 ino
->dentry
= dentry
;
678 spin_lock(&sbi
->lookup_lock
);
679 list_add(&ino
->active
, &sbi
->active_list
);
680 spin_unlock(&sbi
->lookup_lock
);
682 d_instantiate(dentry
, NULL
);
686 spin_lock(&dentry
->d_lock
);
687 dentry
->d_flags
|= DCACHE_AUTOFS_PENDING
;
688 spin_unlock(&dentry
->d_lock
);
689 if (dentry
->d_op
&& dentry
->d_op
->d_revalidate
) {
690 mutex_unlock(&dir
->i_mutex
);
691 (dentry
->d_op
->d_revalidate
)(dentry
, nd
);
692 mutex_lock(&dir
->i_mutex
);
697 * If we are still pending, check if we had to handle
698 * a signal. If so we can force a restart..
700 if (dentry
->d_flags
& DCACHE_AUTOFS_PENDING
) {
701 /* See if we were interrupted */
702 if (signal_pending(current
)) {
703 sigset_t
*sigset
= ¤t
->pending
.signal
;
704 if (sigismember (sigset
, SIGKILL
) ||
705 sigismember (sigset
, SIGQUIT
) ||
706 sigismember (sigset
, SIGINT
)) {
709 return ERR_PTR(-ERESTARTNOINTR
);
713 spin_lock(&dentry
->d_lock
);
714 dentry
->d_flags
&= ~DCACHE_AUTOFS_PENDING
;
715 spin_unlock(&dentry
->d_lock
);
720 * If this dentry is unhashed, then we shouldn't honour this
721 * lookup. Returning ENOENT here doesn't do the right thing
722 * for all system calls, but it should be OK for the operations
723 * we permit from an autofs.
725 if (!oz_mode
&& d_unhashed(dentry
)) {
727 * A user space application can (and has done in the past)
728 * remove and re-create this directory during the callback.
729 * This can leave us with an unhashed dentry, but a
730 * successful mount! So we need to perform another
731 * cached lookup in case the dentry now exists.
733 struct dentry
*parent
= dentry
->d_parent
;
734 struct dentry
*new = d_lookup(parent
, &dentry
->d_name
);
738 dentry
= ERR_PTR(-ENOENT
);
752 static int autofs4_dir_symlink(struct inode
*dir
,
753 struct dentry
*dentry
,
756 struct autofs_sb_info
*sbi
= autofs4_sbi(dir
->i_sb
);
757 struct autofs_info
*ino
= autofs4_dentry_ino(dentry
);
758 struct autofs_info
*p_ino
;
762 DPRINTK("%s <- %.*s", symname
,
763 dentry
->d_name
.len
, dentry
->d_name
.name
);
765 if (!autofs4_oz_mode(sbi
))
768 ino
= autofs4_init_ino(ino
, sbi
, S_IFLNK
| 0555);
772 spin_lock(&sbi
->lookup_lock
);
773 if (!list_empty(&ino
->active
))
774 list_del_init(&ino
->active
);
775 spin_unlock(&sbi
->lookup_lock
);
777 ino
->size
= strlen(symname
);
778 cp
= kmalloc(ino
->size
+ 1, GFP_KERNEL
);
780 if (!dentry
->d_fsdata
)
787 inode
= autofs4_get_inode(dir
->i_sb
, ino
);
790 if (!dentry
->d_fsdata
)
794 d_add(dentry
, inode
);
796 if (dir
== dir
->i_sb
->s_root
->d_inode
)
797 dentry
->d_op
= &autofs4_root_dentry_operations
;
799 dentry
->d_op
= &autofs4_dentry_operations
;
801 dentry
->d_fsdata
= ino
;
802 ino
->dentry
= dget(dentry
);
803 atomic_inc(&ino
->count
);
804 p_ino
= autofs4_dentry_ino(dentry
->d_parent
);
805 if (p_ino
&& dentry
->d_parent
!= dentry
)
806 atomic_inc(&p_ino
->count
);
810 dir
->i_mtime
= CURRENT_TIME
;
818 * Normal filesystems would do a "d_delete()" to tell the VFS dcache
819 * that the file no longer exists. However, doing that means that the
820 * VFS layer can turn the dentry into a negative dentry. We don't want
821 * this, because the unlink is probably the result of an expire.
822 * We simply d_drop it and add it to a expiring list in the super block,
823 * which allows the dentry lookup to check for an incomplete expire.
825 * If a process is blocked on the dentry waiting for the expire to finish,
826 * it will invalidate the dentry and try to mount with a new one.
828 * Also see autofs4_dir_rmdir()..
830 static int autofs4_dir_unlink(struct inode
*dir
, struct dentry
*dentry
)
832 struct autofs_sb_info
*sbi
= autofs4_sbi(dir
->i_sb
);
833 struct autofs_info
*ino
= autofs4_dentry_ino(dentry
);
834 struct autofs_info
*p_ino
;
836 /* This allows root to remove symlinks */
837 if (!autofs4_oz_mode(sbi
) && !capable(CAP_SYS_ADMIN
))
840 if (atomic_dec_and_test(&ino
->count
)) {
841 p_ino
= autofs4_dentry_ino(dentry
->d_parent
);
842 if (p_ino
&& dentry
->d_parent
!= dentry
)
843 atomic_dec(&p_ino
->count
);
847 dentry
->d_inode
->i_size
= 0;
848 clear_nlink(dentry
->d_inode
);
850 dir
->i_mtime
= CURRENT_TIME
;
852 spin_lock(&dcache_lock
);
853 spin_lock(&sbi
->lookup_lock
);
854 if (list_empty(&ino
->expiring
))
855 list_add(&ino
->expiring
, &sbi
->expiring_list
);
856 spin_unlock(&sbi
->lookup_lock
);
857 spin_lock(&dentry
->d_lock
);
859 spin_unlock(&dentry
->d_lock
);
860 spin_unlock(&dcache_lock
);
865 static int autofs4_dir_rmdir(struct inode
*dir
, struct dentry
*dentry
)
867 struct autofs_sb_info
*sbi
= autofs4_sbi(dir
->i_sb
);
868 struct autofs_info
*ino
= autofs4_dentry_ino(dentry
);
869 struct autofs_info
*p_ino
;
871 DPRINTK("dentry %p, removing %.*s",
872 dentry
, dentry
->d_name
.len
, dentry
->d_name
.name
);
874 if (!autofs4_oz_mode(sbi
))
877 spin_lock(&dcache_lock
);
878 if (!list_empty(&dentry
->d_subdirs
)) {
879 spin_unlock(&dcache_lock
);
882 spin_lock(&sbi
->lookup_lock
);
883 if (list_empty(&ino
->expiring
))
884 list_add(&ino
->expiring
, &sbi
->expiring_list
);
885 spin_unlock(&sbi
->lookup_lock
);
886 spin_lock(&dentry
->d_lock
);
888 spin_unlock(&dentry
->d_lock
);
889 spin_unlock(&dcache_lock
);
891 if (atomic_dec_and_test(&ino
->count
)) {
892 p_ino
= autofs4_dentry_ino(dentry
->d_parent
);
893 if (p_ino
&& dentry
->d_parent
!= dentry
)
894 atomic_dec(&p_ino
->count
);
897 dentry
->d_inode
->i_size
= 0;
898 clear_nlink(dentry
->d_inode
);
906 static int autofs4_dir_mkdir(struct inode
*dir
, struct dentry
*dentry
, int mode
)
908 struct autofs_sb_info
*sbi
= autofs4_sbi(dir
->i_sb
);
909 struct autofs_info
*ino
= autofs4_dentry_ino(dentry
);
910 struct autofs_info
*p_ino
;
913 if (!autofs4_oz_mode(sbi
))
916 DPRINTK("dentry %p, creating %.*s",
917 dentry
, dentry
->d_name
.len
, dentry
->d_name
.name
);
919 ino
= autofs4_init_ino(ino
, sbi
, S_IFDIR
| 0555);
923 spin_lock(&sbi
->lookup_lock
);
924 if (!list_empty(&ino
->active
))
925 list_del_init(&ino
->active
);
926 spin_unlock(&sbi
->lookup_lock
);
928 inode
= autofs4_get_inode(dir
->i_sb
, ino
);
930 if (!dentry
->d_fsdata
)
934 d_add(dentry
, inode
);
936 if (dir
== dir
->i_sb
->s_root
->d_inode
)
937 dentry
->d_op
= &autofs4_root_dentry_operations
;
939 dentry
->d_op
= &autofs4_dentry_operations
;
941 dentry
->d_fsdata
= ino
;
942 ino
->dentry
= dget(dentry
);
943 atomic_inc(&ino
->count
);
944 p_ino
= autofs4_dentry_ino(dentry
->d_parent
);
945 if (p_ino
&& dentry
->d_parent
!= dentry
)
946 atomic_inc(&p_ino
->count
);
949 dir
->i_mtime
= CURRENT_TIME
;
954 /* Get/set timeout ioctl() operation */
955 static inline int autofs4_get_set_timeout(struct autofs_sb_info
*sbi
,
956 unsigned long __user
*p
)
959 unsigned long ntimeout
;
961 if ((rv
= get_user(ntimeout
, p
)) ||
962 (rv
= put_user(sbi
->exp_timeout
/HZ
, p
)))
965 if (ntimeout
> ULONG_MAX
/HZ
)
966 sbi
->exp_timeout
= 0;
968 sbi
->exp_timeout
= ntimeout
* HZ
;
973 /* Return protocol version */
974 static inline int autofs4_get_protover(struct autofs_sb_info
*sbi
, int __user
*p
)
976 return put_user(sbi
->version
, p
);
979 /* Return protocol sub version */
980 static inline int autofs4_get_protosubver(struct autofs_sb_info
*sbi
, int __user
*p
)
982 return put_user(sbi
->sub_version
, p
);
986 * Tells the daemon whether we need to reghost or not. Also, clears
987 * the reghost_needed flag.
989 static inline int autofs4_ask_reghost(struct autofs_sb_info
*sbi
, int __user
*p
)
993 DPRINTK("returning %d", sbi
->needs_reghost
);
995 status
= put_user(sbi
->needs_reghost
, p
);
999 sbi
->needs_reghost
= 0;
1004 * Enable / Disable reghosting ioctl() operation
1006 static inline int autofs4_toggle_reghost(struct autofs_sb_info
*sbi
, int __user
*p
)
1011 status
= get_user(val
, p
);
1013 DPRINTK("reghost = %d", val
);
1018 /* turn on/off reghosting, with the val */
1019 sbi
->reghost_enabled
= val
;
1024 * Tells the daemon whether it can umount the autofs mount.
1026 static inline int autofs4_ask_umount(struct vfsmount
*mnt
, int __user
*p
)
1030 if (may_umount(mnt
))
1033 DPRINTK("returning %d", status
);
1035 status
= put_user(status
, p
);
1040 /* Identify autofs4_dentries - this is so we can tell if there's
1041 an extra dentry refcount or not. We only hold a refcount on the
1042 dentry if its non-negative (ie, d_inode != NULL)
1044 int is_autofs4_dentry(struct dentry
*dentry
)
1046 return dentry
&& dentry
->d_inode
&&
1047 (dentry
->d_op
== &autofs4_root_dentry_operations
||
1048 dentry
->d_op
== &autofs4_dentry_operations
) &&
1049 dentry
->d_fsdata
!= NULL
;
1053 * ioctl()'s on the root directory is the chief method for the daemon to
1054 * generate kernel reactions
1056 static int autofs4_root_ioctl(struct inode
*inode
, struct file
*filp
,
1057 unsigned int cmd
, unsigned long arg
)
1059 struct autofs_sb_info
*sbi
= autofs4_sbi(inode
->i_sb
);
1060 void __user
*p
= (void __user
*)arg
;
1062 DPRINTK("cmd = 0x%08x, arg = 0x%08lx, sbi = %p, pgrp = %u",
1063 cmd
,arg
,sbi
,task_pgrp_nr(current
));
1065 if (_IOC_TYPE(cmd
) != _IOC_TYPE(AUTOFS_IOC_FIRST
) ||
1066 _IOC_NR(cmd
) - _IOC_NR(AUTOFS_IOC_FIRST
) >= AUTOFS_IOC_COUNT
)
1069 if (!autofs4_oz_mode(sbi
) && !capable(CAP_SYS_ADMIN
))
1073 case AUTOFS_IOC_READY
: /* Wait queue: go ahead and retry */
1074 return autofs4_wait_release(sbi
,(autofs_wqt_t
)arg
,0);
1075 case AUTOFS_IOC_FAIL
: /* Wait queue: fail with ENOENT */
1076 return autofs4_wait_release(sbi
,(autofs_wqt_t
)arg
,-ENOENT
);
1077 case AUTOFS_IOC_CATATONIC
: /* Enter catatonic mode (daemon shutdown) */
1078 autofs4_catatonic_mode(sbi
);
1080 case AUTOFS_IOC_PROTOVER
: /* Get protocol version */
1081 return autofs4_get_protover(sbi
, p
);
1082 case AUTOFS_IOC_PROTOSUBVER
: /* Get protocol sub version */
1083 return autofs4_get_protosubver(sbi
, p
);
1084 case AUTOFS_IOC_SETTIMEOUT
:
1085 return autofs4_get_set_timeout(sbi
, p
);
1087 case AUTOFS_IOC_TOGGLEREGHOST
:
1088 return autofs4_toggle_reghost(sbi
, p
);
1089 case AUTOFS_IOC_ASKREGHOST
:
1090 return autofs4_ask_reghost(sbi
, p
);
1092 case AUTOFS_IOC_ASKUMOUNT
:
1093 return autofs4_ask_umount(filp
->f_path
.mnt
, p
);
1095 /* return a single thing to expire */
1096 case AUTOFS_IOC_EXPIRE
:
1097 return autofs4_expire_run(inode
->i_sb
,filp
->f_path
.mnt
,sbi
, p
);
1098 /* same as above, but can send multiple expires through pipe */
1099 case AUTOFS_IOC_EXPIRE_MULTI
:
1100 return autofs4_expire_multi(inode
->i_sb
,filp
->f_path
.mnt
,sbi
, p
);