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 2001-2003 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>
20 #include <linux/smp_lock.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 int autofs4_dir_close(struct inode *inode, struct file *file);
30 static int autofs4_dir_readdir(struct file * filp, void * dirent, filldir_t filldir);
31 static int autofs4_root_readdir(struct file * filp, void * dirent, filldir_t filldir);
32 static struct dentry *autofs4_lookup(struct inode *,struct dentry *, struct nameidata *);
34 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 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 struct inode_operations autofs4_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 struct inode_operations autofs4_dir_inode_operations = {
58 .lookup = autofs4_lookup,
59 .unlink = autofs4_dir_unlink,
60 .symlink = autofs4_dir_symlink,
61 .mkdir = autofs4_dir_mkdir,
62 .rmdir = autofs4_dir_rmdir,
65 static int autofs4_root_readdir(struct file *file, void *dirent,
68 struct autofs_sb_info *sbi = autofs4_sbi(file->f_dentry->d_sb);
69 int oz_mode = autofs4_oz_mode(sbi);
71 DPRINTK("called, filp->f_pos = %lld", file->f_pos);
74 * Don't set reghost flag if:
75 * 1) f_pos is larger than zero -- we've already been here.
76 * 2) we haven't even enabled reghosting in the 1st place.
77 * 3) this is the daemon doing a readdir
79 if (oz_mode && file->f_pos == 0 && sbi->reghost_enabled)
80 sbi->needs_reghost = 1;
82 DPRINTK("needs_reghost = %d", sbi->needs_reghost);
84 return dcache_readdir(file, dirent, filldir);
87 /* Update usage from here to top of tree, so that scan of
88 top-level directories will give a useful result */
89 static void autofs4_update_usage(struct vfsmount *mnt, struct dentry *dentry)
91 struct dentry *top = dentry->d_sb->s_root;
93 spin_lock(&dcache_lock);
94 for(; dentry != top; dentry = dentry->d_parent) {
95 struct autofs_info *ino = autofs4_dentry_ino(dentry);
98 touch_atime(mnt, dentry);
99 ino->last_used = jiffies;
102 spin_unlock(&dcache_lock);
105 static int autofs4_dir_open(struct inode *inode, struct file *file)
107 struct dentry *dentry = file->f_dentry;
108 struct vfsmount *mnt = file->f_vfsmnt;
109 struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
110 struct dentry *cursor;
113 status = dcache_dir_open(inode, file);
117 cursor = file->private_data;
118 cursor->d_fsdata = NULL;
120 DPRINTK("file=%p dentry=%p %.*s",
121 file, dentry, dentry->d_name.len, dentry->d_name.name);
123 if (autofs4_oz_mode(sbi))
126 if (autofs4_ispending(dentry)) {
127 DPRINTK("dentry busy");
128 dcache_dir_close(inode, file);
134 if (!d_mountpoint(dentry) && dentry->d_op && dentry->d_op->d_revalidate) {
138 /* In case there are stale directory dentrys from a failed mount */
139 spin_lock(&dcache_lock);
140 empty = list_empty(&dentry->d_subdirs);
141 spin_unlock(&dcache_lock);
144 d_invalidate(dentry);
146 nd.flags = LOOKUP_DIRECTORY;
147 ret = (dentry->d_op->d_revalidate)(dentry, &nd);
150 dcache_dir_close(inode, file);
155 if (d_mountpoint(dentry)) {
156 struct file *fp = NULL;
157 struct vfsmount *fp_mnt = mntget(mnt);
158 struct dentry *fp_dentry = dget(dentry);
160 if (!autofs4_follow_mount(&fp_mnt, &fp_dentry)) {
163 dcache_dir_close(inode, file);
167 fp = dentry_open(fp_dentry, fp_mnt, file->f_flags);
168 status = PTR_ERR(fp);
170 dcache_dir_close(inode, file);
173 cursor->d_fsdata = fp;
180 static int autofs4_dir_close(struct inode *inode, struct file *file)
182 struct dentry *dentry = file->f_dentry;
183 struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
184 struct dentry *cursor = file->private_data;
187 DPRINTK("file=%p dentry=%p %.*s",
188 file, dentry, dentry->d_name.len, dentry->d_name.name);
190 if (autofs4_oz_mode(sbi))
193 if (autofs4_ispending(dentry)) {
194 DPRINTK("dentry busy");
199 if (d_mountpoint(dentry)) {
200 struct file *fp = cursor->d_fsdata;
205 filp_close(fp, current->files);
208 dcache_dir_close(inode, file);
212 static int autofs4_dir_readdir(struct file *file, void *dirent, filldir_t filldir)
214 struct dentry *dentry = file->f_dentry;
215 struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
216 struct dentry *cursor = file->private_data;
219 DPRINTK("file=%p dentry=%p %.*s",
220 file, dentry, dentry->d_name.len, dentry->d_name.name);
222 if (autofs4_oz_mode(sbi))
225 if (autofs4_ispending(dentry)) {
226 DPRINTK("dentry busy");
230 if (d_mountpoint(dentry)) {
231 struct file *fp = cursor->d_fsdata;
236 if (!fp->f_op || !fp->f_op->readdir)
239 status = vfs_readdir(fp, filldir, dirent);
240 file->f_pos = fp->f_pos;
242 autofs4_copy_atime(file, fp);
246 return dcache_readdir(file, dirent, filldir);
249 static int try_to_fill_dentry(struct vfsmount *mnt, struct dentry *dentry, int flags)
251 struct super_block *sb = mnt->mnt_sb;
252 struct autofs_sb_info *sbi = autofs4_sbi(sb);
253 struct autofs_info *ino = autofs4_dentry_ino(dentry);
256 /* Block on any pending expiry here; invalidate the dentry
257 when expiration is done to trigger mount request with a new
259 if (ino && (ino->flags & AUTOFS_INF_EXPIRING)) {
260 DPRINTK("waiting for expire %p name=%.*s",
261 dentry, dentry->d_name.len, dentry->d_name.name);
263 status = autofs4_wait(sbi, dentry, NFY_NONE);
265 DPRINTK("expire done status=%d", status);
268 * If the directory still exists the mount request must
269 * continue otherwise it can't be followed at the right
270 * time during the walk.
272 status = d_invalidate(dentry);
273 if (status != -EBUSY)
277 DPRINTK("dentry=%p %.*s ino=%p",
278 dentry, dentry->d_name.len, dentry->d_name.name, dentry->d_inode);
281 * Wait for a pending mount, triggering one if there
284 if (dentry->d_inode == NULL) {
285 DPRINTK("waiting for mount name=%.*s",
286 dentry->d_name.len, dentry->d_name.name);
288 status = autofs4_wait(sbi, dentry, NFY_MOUNT);
290 DPRINTK("mount done status=%d", status);
292 if (status && dentry->d_inode)
293 return 0; /* Try to get the kernel to invalidate this dentry */
295 /* Turn this into a real negative dentry? */
296 if (status == -ENOENT) {
297 spin_lock(&dentry->d_lock);
298 dentry->d_flags &= ~DCACHE_AUTOFS_PENDING;
299 spin_unlock(&dentry->d_lock);
302 /* Return a negative dentry, but leave it "pending" */
305 /* Trigger mount for path component or follow link */
306 } else if (flags & (LOOKUP_CONTINUE | LOOKUP_DIRECTORY) ||
307 current->link_count) {
308 DPRINTK("waiting for mount name=%.*s",
309 dentry->d_name.len, dentry->d_name.name);
311 spin_lock(&dentry->d_lock);
312 dentry->d_flags |= DCACHE_AUTOFS_PENDING;
313 spin_unlock(&dentry->d_lock);
314 status = autofs4_wait(sbi, dentry, NFY_MOUNT);
316 DPRINTK("mount done status=%d", status);
319 spin_lock(&dentry->d_lock);
320 dentry->d_flags &= ~DCACHE_AUTOFS_PENDING;
321 spin_unlock(&dentry->d_lock);
327 * We don't update the usages for the autofs daemon itself, this
328 * is necessary for recursive autofs mounts
330 if (!autofs4_oz_mode(sbi))
331 autofs4_update_usage(mnt, dentry);
333 /* Initialize expiry counter after successful mount */
335 ino->last_used = jiffies;
337 spin_lock(&dentry->d_lock);
338 dentry->d_flags &= ~DCACHE_AUTOFS_PENDING;
339 spin_unlock(&dentry->d_lock);
344 * Revalidate is called on every cache lookup. Some of those
345 * cache lookups may actually happen while the dentry is not
346 * yet completely filled in, and revalidate has to delay such
349 static int autofs4_revalidate(struct dentry *dentry, struct nameidata *nd)
351 struct inode *dir = dentry->d_parent->d_inode;
352 struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb);
353 int oz_mode = autofs4_oz_mode(sbi);
354 int flags = nd ? nd->flags : 0;
358 if (autofs4_ispending(dentry)) {
360 status = try_to_fill_dentry(nd->mnt, dentry, flags);
364 /* Negative dentry.. invalidate if "old" */
365 if (dentry->d_inode == NULL)
368 /* Check for a non-mountpoint directory with no contents */
369 spin_lock(&dcache_lock);
370 if (S_ISDIR(dentry->d_inode->i_mode) &&
371 !d_mountpoint(dentry) &&
372 simple_empty_nolock(dentry)) {
373 DPRINTK("dentry=%p %.*s, emptydir",
374 dentry, dentry->d_name.len, dentry->d_name.name);
375 spin_unlock(&dcache_lock);
377 status = try_to_fill_dentry(nd->mnt, dentry, flags);
380 spin_unlock(&dcache_lock);
382 /* Update the usage list */
384 autofs4_update_usage(nd->mnt, dentry);
389 static void autofs4_dentry_release(struct dentry *de)
391 struct autofs_info *inf;
393 DPRINTK("releasing %p", de);
395 inf = autofs4_dentry_ino(de);
402 autofs4_free_ino(inf);
406 /* For dentries of directories in the root dir */
407 static struct dentry_operations autofs4_root_dentry_operations = {
408 .d_revalidate = autofs4_revalidate,
409 .d_release = autofs4_dentry_release,
412 /* For other dentries */
413 static struct dentry_operations autofs4_dentry_operations = {
414 .d_revalidate = autofs4_revalidate,
415 .d_release = autofs4_dentry_release,
418 /* Lookups in the root directory */
419 static struct dentry *autofs4_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd)
421 struct autofs_sb_info *sbi;
424 DPRINTK("name = %.*s",
425 dentry->d_name.len, dentry->d_name.name);
427 /* File name too long to exist */
428 if (dentry->d_name.len > NAME_MAX)
429 return ERR_PTR(-ENAMETOOLONG);
431 sbi = autofs4_sbi(dir->i_sb);
432 oz_mode = autofs4_oz_mode(sbi);
434 DPRINTK("pid = %u, pgrp = %u, catatonic = %d, oz_mode = %d",
435 current->pid, process_group(current), sbi->catatonic, oz_mode);
438 * Mark the dentry incomplete, but add it. This is needed so
439 * that the VFS layer knows about the dentry, and we can count
440 * on catching any lookups through the revalidate.
442 * Let all the hard work be done by the revalidate function that
443 * needs to be able to do this anyway..
445 * We need to do this before we release the directory semaphore.
447 dentry->d_op = &autofs4_root_dentry_operations;
450 spin_lock(&dentry->d_lock);
451 dentry->d_flags |= DCACHE_AUTOFS_PENDING;
452 spin_unlock(&dentry->d_lock);
454 dentry->d_fsdata = NULL;
457 if (dentry->d_op && dentry->d_op->d_revalidate) {
458 mutex_unlock(&dir->i_mutex);
459 (dentry->d_op->d_revalidate)(dentry, nd);
460 mutex_lock(&dir->i_mutex);
464 * If we are still pending, check if we had to handle
465 * a signal. If so we can force a restart..
467 if (dentry->d_flags & DCACHE_AUTOFS_PENDING) {
468 /* See if we were interrupted */
469 if (signal_pending(current)) {
470 sigset_t *sigset = ¤t->pending.signal;
471 if (sigismember (sigset, SIGKILL) ||
472 sigismember (sigset, SIGQUIT) ||
473 sigismember (sigset, SIGINT)) {
474 return ERR_PTR(-ERESTARTNOINTR);
480 * If this dentry is unhashed, then we shouldn't honour this
481 * lookup even if the dentry is positive. Returning ENOENT here
482 * doesn't do the right thing for all system calls, but it should
483 * be OK for the operations we permit from an autofs.
485 if (dentry->d_inode && d_unhashed(dentry))
486 return ERR_PTR(-ENOENT);
491 static int autofs4_dir_symlink(struct inode *dir,
492 struct dentry *dentry,
495 struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb);
496 struct autofs_info *ino = autofs4_dentry_ino(dentry);
497 struct autofs_info *p_ino;
501 DPRINTK("%s <- %.*s", symname,
502 dentry->d_name.len, dentry->d_name.name);
504 if (!autofs4_oz_mode(sbi))
507 ino = autofs4_init_ino(ino, sbi, S_IFLNK | 0555);
511 ino->size = strlen(symname);
512 ino->u.symlink = cp = kmalloc(ino->size + 1, GFP_KERNEL);
521 inode = autofs4_get_inode(dir->i_sb, ino);
522 d_instantiate(dentry, inode);
524 if (dir == dir->i_sb->s_root->d_inode)
525 dentry->d_op = &autofs4_root_dentry_operations;
527 dentry->d_op = &autofs4_dentry_operations;
529 dentry->d_fsdata = ino;
530 ino->dentry = dget(dentry);
531 atomic_inc(&ino->count);
532 p_ino = autofs4_dentry_ino(dentry->d_parent);
533 if (p_ino && dentry->d_parent != dentry)
534 atomic_inc(&p_ino->count);
537 dir->i_mtime = CURRENT_TIME;
545 * Normal filesystems would do a "d_delete()" to tell the VFS dcache
546 * that the file no longer exists. However, doing that means that the
547 * VFS layer can turn the dentry into a negative dentry. We don't want
548 * this, because since the unlink is probably the result of an expire.
549 * We simply d_drop it, which allows the dentry lookup to remount it
552 * If a process is blocked on the dentry waiting for the expire to finish,
553 * it will invalidate the dentry and try to mount with a new one.
555 * Also see autofs4_dir_rmdir()..
557 static int autofs4_dir_unlink(struct inode *dir, struct dentry *dentry)
559 struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb);
560 struct autofs_info *ino = autofs4_dentry_ino(dentry);
561 struct autofs_info *p_ino;
563 /* This allows root to remove symlinks */
564 if ( !autofs4_oz_mode(sbi) && !capable(CAP_SYS_ADMIN) )
567 if (atomic_dec_and_test(&ino->count)) {
568 p_ino = autofs4_dentry_ino(dentry->d_parent);
569 if (p_ino && dentry->d_parent != dentry)
570 atomic_dec(&p_ino->count);
574 dentry->d_inode->i_size = 0;
575 dentry->d_inode->i_nlink = 0;
577 dir->i_mtime = CURRENT_TIME;
584 static int autofs4_dir_rmdir(struct inode *dir, struct dentry *dentry)
586 struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb);
587 struct autofs_info *ino = autofs4_dentry_ino(dentry);
588 struct autofs_info *p_ino;
590 if (!autofs4_oz_mode(sbi))
593 spin_lock(&dcache_lock);
594 if (!list_empty(&dentry->d_subdirs)) {
595 spin_unlock(&dcache_lock);
598 spin_lock(&dentry->d_lock);
600 spin_unlock(&dentry->d_lock);
601 spin_unlock(&dcache_lock);
603 if (atomic_dec_and_test(&ino->count)) {
604 p_ino = autofs4_dentry_ino(dentry->d_parent);
605 if (p_ino && dentry->d_parent != dentry)
606 atomic_dec(&p_ino->count);
609 dentry->d_inode->i_size = 0;
610 dentry->d_inode->i_nlink = 0;
618 static int autofs4_dir_mkdir(struct inode *dir, struct dentry *dentry, int mode)
620 struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb);
621 struct autofs_info *ino = autofs4_dentry_ino(dentry);
622 struct autofs_info *p_ino;
625 if ( !autofs4_oz_mode(sbi) )
628 DPRINTK("dentry %p, creating %.*s",
629 dentry, dentry->d_name.len, dentry->d_name.name);
631 ino = autofs4_init_ino(ino, sbi, S_IFDIR | 0555);
635 inode = autofs4_get_inode(dir->i_sb, ino);
636 d_instantiate(dentry, inode);
638 if (dir == dir->i_sb->s_root->d_inode)
639 dentry->d_op = &autofs4_root_dentry_operations;
641 dentry->d_op = &autofs4_dentry_operations;
643 dentry->d_fsdata = ino;
644 ino->dentry = dget(dentry);
645 atomic_inc(&ino->count);
646 p_ino = autofs4_dentry_ino(dentry->d_parent);
647 if (p_ino && dentry->d_parent != dentry)
648 atomic_inc(&p_ino->count);
651 dir->i_mtime = CURRENT_TIME;
656 /* Get/set timeout ioctl() operation */
657 static inline int autofs4_get_set_timeout(struct autofs_sb_info *sbi,
658 unsigned long __user *p)
661 unsigned long ntimeout;
663 if ( (rv = get_user(ntimeout, p)) ||
664 (rv = put_user(sbi->exp_timeout/HZ, p)) )
667 if ( ntimeout > ULONG_MAX/HZ )
668 sbi->exp_timeout = 0;
670 sbi->exp_timeout = ntimeout * HZ;
675 /* Return protocol version */
676 static inline int autofs4_get_protover(struct autofs_sb_info *sbi, int __user *p)
678 return put_user(sbi->version, p);
681 /* Return protocol sub version */
682 static inline int autofs4_get_protosubver(struct autofs_sb_info *sbi, int __user *p)
684 return put_user(sbi->sub_version, p);
688 * Tells the daemon whether we need to reghost or not. Also, clears
689 * the reghost_needed flag.
691 static inline int autofs4_ask_reghost(struct autofs_sb_info *sbi, int __user *p)
695 DPRINTK("returning %d", sbi->needs_reghost);
697 status = put_user(sbi->needs_reghost, p);
701 sbi->needs_reghost = 0;
706 * Enable / Disable reghosting ioctl() operation
708 static inline int autofs4_toggle_reghost(struct autofs_sb_info *sbi, int __user *p)
713 status = get_user(val, p);
715 DPRINTK("reghost = %d", val);
720 /* turn on/off reghosting, with the val */
721 sbi->reghost_enabled = val;
726 * Tells the daemon whether it can umount the autofs mount.
728 static inline int autofs4_ask_umount(struct vfsmount *mnt, int __user *p)
732 if (may_umount(mnt) == 0)
735 DPRINTK("returning %d", status);
737 status = put_user(status, p);
742 /* Identify autofs4_dentries - this is so we can tell if there's
743 an extra dentry refcount or not. We only hold a refcount on the
744 dentry if its non-negative (ie, d_inode != NULL)
746 int is_autofs4_dentry(struct dentry *dentry)
748 return dentry && dentry->d_inode &&
749 (dentry->d_op == &autofs4_root_dentry_operations ||
750 dentry->d_op == &autofs4_dentry_operations) &&
751 dentry->d_fsdata != NULL;
755 * ioctl()'s on the root directory is the chief method for the daemon to
756 * generate kernel reactions
758 static int autofs4_root_ioctl(struct inode *inode, struct file *filp,
759 unsigned int cmd, unsigned long arg)
761 struct autofs_sb_info *sbi = autofs4_sbi(inode->i_sb);
762 void __user *p = (void __user *)arg;
764 DPRINTK("cmd = 0x%08x, arg = 0x%08lx, sbi = %p, pgrp = %u",
765 cmd,arg,sbi,process_group(current));
767 if ( _IOC_TYPE(cmd) != _IOC_TYPE(AUTOFS_IOC_FIRST) ||
768 _IOC_NR(cmd) - _IOC_NR(AUTOFS_IOC_FIRST) >= AUTOFS_IOC_COUNT )
771 if ( !autofs4_oz_mode(sbi) && !capable(CAP_SYS_ADMIN) )
775 case AUTOFS_IOC_READY: /* Wait queue: go ahead and retry */
776 return autofs4_wait_release(sbi,(autofs_wqt_t)arg,0);
777 case AUTOFS_IOC_FAIL: /* Wait queue: fail with ENOENT */
778 return autofs4_wait_release(sbi,(autofs_wqt_t)arg,-ENOENT);
779 case AUTOFS_IOC_CATATONIC: /* Enter catatonic mode (daemon shutdown) */
780 autofs4_catatonic_mode(sbi);
782 case AUTOFS_IOC_PROTOVER: /* Get protocol version */
783 return autofs4_get_protover(sbi, p);
784 case AUTOFS_IOC_PROTOSUBVER: /* Get protocol sub version */
785 return autofs4_get_protosubver(sbi, p);
786 case AUTOFS_IOC_SETTIMEOUT:
787 return autofs4_get_set_timeout(sbi, p);
789 case AUTOFS_IOC_TOGGLEREGHOST:
790 return autofs4_toggle_reghost(sbi, p);
791 case AUTOFS_IOC_ASKREGHOST:
792 return autofs4_ask_reghost(sbi, p);
794 case AUTOFS_IOC_ASKUMOUNT:
795 return autofs4_ask_umount(filp->f_vfsmnt, p);
797 /* return a single thing to expire */
798 case AUTOFS_IOC_EXPIRE:
799 return autofs4_expire_run(inode->i_sb,filp->f_vfsmnt,sbi, p);
800 /* same as above, but can send multiple expires through pipe */
801 case AUTOFS_IOC_EXPIRE_MULTI:
802 return autofs4_expire_multi(inode->i_sb,filp->f_vfsmnt,sbi, p);