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 spin_lock(&dentry->d_lock);
334 dentry->d_flags &= ~DCACHE_AUTOFS_PENDING;
335 spin_unlock(&dentry->d_lock);
340 * Revalidate is called on every cache lookup. Some of those
341 * cache lookups may actually happen while the dentry is not
342 * yet completely filled in, and revalidate has to delay such
345 static int autofs4_revalidate(struct dentry *dentry, struct nameidata *nd)
347 struct inode *dir = dentry->d_parent->d_inode;
348 struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb);
349 int oz_mode = autofs4_oz_mode(sbi);
350 int flags = nd ? nd->flags : 0;
354 if (autofs4_ispending(dentry)) {
356 status = try_to_fill_dentry(nd->mnt, dentry, flags);
360 /* Negative dentry.. invalidate if "old" */
361 if (dentry->d_inode == NULL)
364 /* Check for a non-mountpoint directory with no contents */
365 spin_lock(&dcache_lock);
366 if (S_ISDIR(dentry->d_inode->i_mode) &&
367 !d_mountpoint(dentry) &&
368 simple_empty_nolock(dentry)) {
369 DPRINTK("dentry=%p %.*s, emptydir",
370 dentry, dentry->d_name.len, dentry->d_name.name);
371 spin_unlock(&dcache_lock);
373 status = try_to_fill_dentry(nd->mnt, dentry, flags);
376 spin_unlock(&dcache_lock);
378 /* Update the usage list */
380 autofs4_update_usage(nd->mnt, dentry);
385 static void autofs4_dentry_release(struct dentry *de)
387 struct autofs_info *inf;
389 DPRINTK("releasing %p", de);
391 inf = autofs4_dentry_ino(de);
398 autofs4_free_ino(inf);
402 /* For dentries of directories in the root dir */
403 static struct dentry_operations autofs4_root_dentry_operations = {
404 .d_revalidate = autofs4_revalidate,
405 .d_release = autofs4_dentry_release,
408 /* For other dentries */
409 static struct dentry_operations autofs4_dentry_operations = {
410 .d_revalidate = autofs4_revalidate,
411 .d_release = autofs4_dentry_release,
414 /* Lookups in the root directory */
415 static struct dentry *autofs4_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd)
417 struct autofs_sb_info *sbi;
420 DPRINTK("name = %.*s",
421 dentry->d_name.len, dentry->d_name.name);
423 /* File name too long to exist */
424 if (dentry->d_name.len > NAME_MAX)
425 return ERR_PTR(-ENAMETOOLONG);
427 sbi = autofs4_sbi(dir->i_sb);
428 oz_mode = autofs4_oz_mode(sbi);
430 DPRINTK("pid = %u, pgrp = %u, catatonic = %d, oz_mode = %d",
431 current->pid, process_group(current), sbi->catatonic, oz_mode);
434 * Mark the dentry incomplete, but add it. This is needed so
435 * that the VFS layer knows about the dentry, and we can count
436 * on catching any lookups through the revalidate.
438 * Let all the hard work be done by the revalidate function that
439 * needs to be able to do this anyway..
441 * We need to do this before we release the directory semaphore.
443 dentry->d_op = &autofs4_root_dentry_operations;
446 spin_lock(&dentry->d_lock);
447 dentry->d_flags |= DCACHE_AUTOFS_PENDING;
448 spin_unlock(&dentry->d_lock);
450 dentry->d_fsdata = NULL;
453 if (dentry->d_op && dentry->d_op->d_revalidate) {
454 mutex_unlock(&dir->i_mutex);
455 (dentry->d_op->d_revalidate)(dentry, nd);
456 mutex_lock(&dir->i_mutex);
460 * If we are still pending, check if we had to handle
461 * a signal. If so we can force a restart..
463 if (dentry->d_flags & DCACHE_AUTOFS_PENDING) {
464 /* See if we were interrupted */
465 if (signal_pending(current)) {
466 sigset_t *sigset = ¤t->pending.signal;
467 if (sigismember (sigset, SIGKILL) ||
468 sigismember (sigset, SIGQUIT) ||
469 sigismember (sigset, SIGINT)) {
470 return ERR_PTR(-ERESTARTNOINTR);
476 * If this dentry is unhashed, then we shouldn't honour this
477 * lookup even if the dentry is positive. Returning ENOENT here
478 * doesn't do the right thing for all system calls, but it should
479 * be OK for the operations we permit from an autofs.
481 if (dentry->d_inode && d_unhashed(dentry))
482 return ERR_PTR(-ENOENT);
487 static int autofs4_dir_symlink(struct inode *dir,
488 struct dentry *dentry,
491 struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb);
492 struct autofs_info *ino = autofs4_dentry_ino(dentry);
493 struct autofs_info *p_ino;
497 DPRINTK("%s <- %.*s", symname,
498 dentry->d_name.len, dentry->d_name.name);
500 if (!autofs4_oz_mode(sbi))
503 ino = autofs4_init_ino(ino, sbi, S_IFLNK | 0555);
507 ino->size = strlen(symname);
508 ino->u.symlink = cp = kmalloc(ino->size + 1, GFP_KERNEL);
517 inode = autofs4_get_inode(dir->i_sb, ino);
518 d_instantiate(dentry, inode);
520 if (dir == dir->i_sb->s_root->d_inode)
521 dentry->d_op = &autofs4_root_dentry_operations;
523 dentry->d_op = &autofs4_dentry_operations;
525 dentry->d_fsdata = ino;
526 ino->dentry = dget(dentry);
527 atomic_inc(&ino->count);
528 p_ino = autofs4_dentry_ino(dentry->d_parent);
529 if (p_ino && dentry->d_parent != dentry)
530 atomic_inc(&p_ino->count);
533 dir->i_mtime = CURRENT_TIME;
541 * Normal filesystems would do a "d_delete()" to tell the VFS dcache
542 * that the file no longer exists. However, doing that means that the
543 * VFS layer can turn the dentry into a negative dentry. We don't want
544 * this, because since the unlink is probably the result of an expire.
545 * We simply d_drop it, which allows the dentry lookup to remount it
548 * If a process is blocked on the dentry waiting for the expire to finish,
549 * it will invalidate the dentry and try to mount with a new one.
551 * Also see autofs4_dir_rmdir()..
553 static int autofs4_dir_unlink(struct inode *dir, struct dentry *dentry)
555 struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb);
556 struct autofs_info *ino = autofs4_dentry_ino(dentry);
557 struct autofs_info *p_ino;
559 /* This allows root to remove symlinks */
560 if ( !autofs4_oz_mode(sbi) && !capable(CAP_SYS_ADMIN) )
563 if (atomic_dec_and_test(&ino->count)) {
564 p_ino = autofs4_dentry_ino(dentry->d_parent);
565 if (p_ino && dentry->d_parent != dentry)
566 atomic_dec(&p_ino->count);
570 dentry->d_inode->i_size = 0;
571 dentry->d_inode->i_nlink = 0;
573 dir->i_mtime = CURRENT_TIME;
580 static int autofs4_dir_rmdir(struct inode *dir, struct dentry *dentry)
582 struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb);
583 struct autofs_info *ino = autofs4_dentry_ino(dentry);
584 struct autofs_info *p_ino;
586 if (!autofs4_oz_mode(sbi))
589 spin_lock(&dcache_lock);
590 if (!list_empty(&dentry->d_subdirs)) {
591 spin_unlock(&dcache_lock);
594 spin_lock(&dentry->d_lock);
596 spin_unlock(&dentry->d_lock);
597 spin_unlock(&dcache_lock);
599 if (atomic_dec_and_test(&ino->count)) {
600 p_ino = autofs4_dentry_ino(dentry->d_parent);
601 if (p_ino && dentry->d_parent != dentry)
602 atomic_dec(&p_ino->count);
605 dentry->d_inode->i_size = 0;
606 dentry->d_inode->i_nlink = 0;
614 static int autofs4_dir_mkdir(struct inode *dir, struct dentry *dentry, int mode)
616 struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb);
617 struct autofs_info *ino = autofs4_dentry_ino(dentry);
618 struct autofs_info *p_ino;
621 if ( !autofs4_oz_mode(sbi) )
624 DPRINTK("dentry %p, creating %.*s",
625 dentry, dentry->d_name.len, dentry->d_name.name);
627 ino = autofs4_init_ino(ino, sbi, S_IFDIR | 0555);
631 inode = autofs4_get_inode(dir->i_sb, ino);
632 d_instantiate(dentry, inode);
634 if (dir == dir->i_sb->s_root->d_inode)
635 dentry->d_op = &autofs4_root_dentry_operations;
637 dentry->d_op = &autofs4_dentry_operations;
639 dentry->d_fsdata = ino;
640 ino->dentry = dget(dentry);
641 atomic_inc(&ino->count);
642 p_ino = autofs4_dentry_ino(dentry->d_parent);
643 if (p_ino && dentry->d_parent != dentry)
644 atomic_inc(&p_ino->count);
647 dir->i_mtime = CURRENT_TIME;
652 /* Get/set timeout ioctl() operation */
653 static inline int autofs4_get_set_timeout(struct autofs_sb_info *sbi,
654 unsigned long __user *p)
657 unsigned long ntimeout;
659 if ( (rv = get_user(ntimeout, p)) ||
660 (rv = put_user(sbi->exp_timeout/HZ, p)) )
663 if ( ntimeout > ULONG_MAX/HZ )
664 sbi->exp_timeout = 0;
666 sbi->exp_timeout = ntimeout * HZ;
671 /* Return protocol version */
672 static inline int autofs4_get_protover(struct autofs_sb_info *sbi, int __user *p)
674 return put_user(sbi->version, p);
677 /* Return protocol sub version */
678 static inline int autofs4_get_protosubver(struct autofs_sb_info *sbi, int __user *p)
680 return put_user(sbi->sub_version, p);
684 * Tells the daemon whether we need to reghost or not. Also, clears
685 * the reghost_needed flag.
687 static inline int autofs4_ask_reghost(struct autofs_sb_info *sbi, int __user *p)
691 DPRINTK("returning %d", sbi->needs_reghost);
693 status = put_user(sbi->needs_reghost, p);
697 sbi->needs_reghost = 0;
702 * Enable / Disable reghosting ioctl() operation
704 static inline int autofs4_toggle_reghost(struct autofs_sb_info *sbi, int __user *p)
709 status = get_user(val, p);
711 DPRINTK("reghost = %d", val);
716 /* turn on/off reghosting, with the val */
717 sbi->reghost_enabled = val;
722 * Tells the daemon whether it can umount the autofs mount.
724 static inline int autofs4_ask_umount(struct vfsmount *mnt, int __user *p)
728 if (may_umount(mnt) == 0)
731 DPRINTK("returning %d", status);
733 status = put_user(status, p);
738 /* Identify autofs4_dentries - this is so we can tell if there's
739 an extra dentry refcount or not. We only hold a refcount on the
740 dentry if its non-negative (ie, d_inode != NULL)
742 int is_autofs4_dentry(struct dentry *dentry)
744 return dentry && dentry->d_inode &&
745 (dentry->d_op == &autofs4_root_dentry_operations ||
746 dentry->d_op == &autofs4_dentry_operations) &&
747 dentry->d_fsdata != NULL;
751 * ioctl()'s on the root directory is the chief method for the daemon to
752 * generate kernel reactions
754 static int autofs4_root_ioctl(struct inode *inode, struct file *filp,
755 unsigned int cmd, unsigned long arg)
757 struct autofs_sb_info *sbi = autofs4_sbi(inode->i_sb);
758 void __user *p = (void __user *)arg;
760 DPRINTK("cmd = 0x%08x, arg = 0x%08lx, sbi = %p, pgrp = %u",
761 cmd,arg,sbi,process_group(current));
763 if ( _IOC_TYPE(cmd) != _IOC_TYPE(AUTOFS_IOC_FIRST) ||
764 _IOC_NR(cmd) - _IOC_NR(AUTOFS_IOC_FIRST) >= AUTOFS_IOC_COUNT )
767 if ( !autofs4_oz_mode(sbi) && !capable(CAP_SYS_ADMIN) )
771 case AUTOFS_IOC_READY: /* Wait queue: go ahead and retry */
772 return autofs4_wait_release(sbi,(autofs_wqt_t)arg,0);
773 case AUTOFS_IOC_FAIL: /* Wait queue: fail with ENOENT */
774 return autofs4_wait_release(sbi,(autofs_wqt_t)arg,-ENOENT);
775 case AUTOFS_IOC_CATATONIC: /* Enter catatonic mode (daemon shutdown) */
776 autofs4_catatonic_mode(sbi);
778 case AUTOFS_IOC_PROTOVER: /* Get protocol version */
779 return autofs4_get_protover(sbi, p);
780 case AUTOFS_IOC_PROTOSUBVER: /* Get protocol sub version */
781 return autofs4_get_protosubver(sbi, p);
782 case AUTOFS_IOC_SETTIMEOUT:
783 return autofs4_get_set_timeout(sbi, p);
785 case AUTOFS_IOC_TOGGLEREGHOST:
786 return autofs4_toggle_reghost(sbi, p);
787 case AUTOFS_IOC_ASKREGHOST:
788 return autofs4_ask_reghost(sbi, p);
790 case AUTOFS_IOC_ASKUMOUNT:
791 return autofs4_ask_umount(filp->f_vfsmnt, p);
793 /* return a single thing to expire */
794 case AUTOFS_IOC_EXPIRE:
795 return autofs4_expire_run(inode->i_sb,filp->f_vfsmnt,sbi, p);
796 /* same as above, but can send multiple expires through pipe */
797 case AUTOFS_IOC_EXPIRE_MULTI:
798 return autofs4_expire_multi(inode->i_sb,filp->f_vfsmnt,sbi, p);