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 dentry->d_time = jiffies + AUTOFS_NEGATIVE_TIMEOUT;
298 spin_lock(&dentry->d_lock);
299 dentry->d_flags &= ~DCACHE_AUTOFS_PENDING;
300 spin_unlock(&dentry->d_lock);
303 /* Return a negative dentry, but leave it "pending" */
306 /* Trigger mount for path component or follow link */
307 } else if (flags & (LOOKUP_CONTINUE | LOOKUP_DIRECTORY) ||
308 current->link_count) {
309 DPRINTK("waiting for mount name=%.*s",
310 dentry->d_name.len, dentry->d_name.name);
312 spin_lock(&dentry->d_lock);
313 dentry->d_flags |= DCACHE_AUTOFS_PENDING;
314 spin_unlock(&dentry->d_lock);
315 status = autofs4_wait(sbi, dentry, NFY_MOUNT);
317 DPRINTK("mount done status=%d", status);
320 spin_lock(&dentry->d_lock);
321 dentry->d_flags &= ~DCACHE_AUTOFS_PENDING;
322 spin_unlock(&dentry->d_lock);
328 * We don't update the usages for the autofs daemon itself, this
329 * is necessary for recursive autofs mounts
331 if (!autofs4_oz_mode(sbi))
332 autofs4_update_usage(mnt, dentry);
334 spin_lock(&dentry->d_lock);
335 dentry->d_flags &= ~DCACHE_AUTOFS_PENDING;
336 spin_unlock(&dentry->d_lock);
341 * Revalidate is called on every cache lookup. Some of those
342 * cache lookups may actually happen while the dentry is not
343 * yet completely filled in, and revalidate has to delay such
346 static int autofs4_revalidate(struct dentry *dentry, struct nameidata *nd)
348 struct inode *dir = dentry->d_parent->d_inode;
349 struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb);
350 int oz_mode = autofs4_oz_mode(sbi);
351 int flags = nd ? nd->flags : 0;
355 if (autofs4_ispending(dentry)) {
357 status = try_to_fill_dentry(nd->mnt, dentry, flags);
361 /* Negative dentry.. invalidate if "old" */
362 if (dentry->d_inode == NULL)
363 return (dentry->d_time - jiffies <= AUTOFS_NEGATIVE_TIMEOUT);
365 /* Check for a non-mountpoint directory with no contents */
366 spin_lock(&dcache_lock);
367 if (S_ISDIR(dentry->d_inode->i_mode) &&
368 !d_mountpoint(dentry) &&
369 list_empty(&dentry->d_subdirs)) {
370 DPRINTK("dentry=%p %.*s, emptydir",
371 dentry, dentry->d_name.len, dentry->d_name.name);
372 spin_unlock(&dcache_lock);
374 status = try_to_fill_dentry(nd->mnt, dentry, flags);
377 spin_unlock(&dcache_lock);
379 /* Update the usage list */
381 autofs4_update_usage(nd->mnt, dentry);
386 static void autofs4_dentry_release(struct dentry *de)
388 struct autofs_info *inf;
390 DPRINTK("releasing %p", de);
392 inf = autofs4_dentry_ino(de);
399 autofs4_free_ino(inf);
403 /* For dentries of directories in the root dir */
404 static struct dentry_operations autofs4_root_dentry_operations = {
405 .d_revalidate = autofs4_revalidate,
406 .d_release = autofs4_dentry_release,
409 /* For other dentries */
410 static struct dentry_operations autofs4_dentry_operations = {
411 .d_revalidate = autofs4_revalidate,
412 .d_release = autofs4_dentry_release,
415 /* Lookups in the root directory */
416 static struct dentry *autofs4_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd)
418 struct autofs_sb_info *sbi;
421 DPRINTK("name = %.*s",
422 dentry->d_name.len, dentry->d_name.name);
424 /* File name too long to exist */
425 if (dentry->d_name.len > NAME_MAX)
426 return ERR_PTR(-ENAMETOOLONG);
428 sbi = autofs4_sbi(dir->i_sb);
429 oz_mode = autofs4_oz_mode(sbi);
431 DPRINTK("pid = %u, pgrp = %u, catatonic = %d, oz_mode = %d",
432 current->pid, process_group(current), sbi->catatonic, oz_mode);
435 * Mark the dentry incomplete, but add it. This is needed so
436 * that the VFS layer knows about the dentry, and we can count
437 * on catching any lookups through the revalidate.
439 * Let all the hard work be done by the revalidate function that
440 * needs to be able to do this anyway..
442 * We need to do this before we release the directory semaphore.
444 dentry->d_op = &autofs4_root_dentry_operations;
447 spin_lock(&dentry->d_lock);
448 dentry->d_flags |= DCACHE_AUTOFS_PENDING;
449 spin_unlock(&dentry->d_lock);
451 dentry->d_fsdata = NULL;
454 if (dentry->d_op && dentry->d_op->d_revalidate) {
455 mutex_unlock(&dir->i_mutex);
456 (dentry->d_op->d_revalidate)(dentry, nd);
457 mutex_lock(&dir->i_mutex);
461 * If we are still pending, check if we had to handle
462 * a signal. If so we can force a restart..
464 if (dentry->d_flags & DCACHE_AUTOFS_PENDING) {
465 /* See if we were interrupted */
466 if (signal_pending(current)) {
467 sigset_t *sigset = ¤t->pending.signal;
468 if (sigismember (sigset, SIGKILL) ||
469 sigismember (sigset, SIGQUIT) ||
470 sigismember (sigset, SIGINT)) {
471 return ERR_PTR(-ERESTARTNOINTR);
477 * If this dentry is unhashed, then we shouldn't honour this
478 * lookup even if the dentry is positive. Returning ENOENT here
479 * doesn't do the right thing for all system calls, but it should
480 * be OK for the operations we permit from an autofs.
482 if (dentry->d_inode && d_unhashed(dentry))
483 return ERR_PTR(-ENOENT);
488 static int autofs4_dir_symlink(struct inode *dir,
489 struct dentry *dentry,
492 struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb);
493 struct autofs_info *ino = autofs4_dentry_ino(dentry);
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);
529 dir->i_mtime = CURRENT_TIME;
537 * Normal filesystems would do a "d_delete()" to tell the VFS dcache
538 * that the file no longer exists. However, doing that means that the
539 * VFS layer can turn the dentry into a negative dentry. We don't want
540 * this, because since the unlink is probably the result of an expire.
541 * We simply d_drop it, which allows the dentry lookup to remount it
544 * If a process is blocked on the dentry waiting for the expire to finish,
545 * it will invalidate the dentry and try to mount with a new one.
547 * Also see autofs4_dir_rmdir()..
549 static int autofs4_dir_unlink(struct inode *dir, struct dentry *dentry)
551 struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb);
552 struct autofs_info *ino = autofs4_dentry_ino(dentry);
554 /* This allows root to remove symlinks */
555 if ( !autofs4_oz_mode(sbi) && !capable(CAP_SYS_ADMIN) )
560 dentry->d_inode->i_size = 0;
561 dentry->d_inode->i_nlink = 0;
563 dir->i_mtime = CURRENT_TIME;
570 static int autofs4_dir_rmdir(struct inode *dir, struct dentry *dentry)
572 struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb);
573 struct autofs_info *ino = autofs4_dentry_ino(dentry);
575 if (!autofs4_oz_mode(sbi))
578 spin_lock(&dcache_lock);
579 if (!list_empty(&dentry->d_subdirs)) {
580 spin_unlock(&dcache_lock);
583 spin_lock(&dentry->d_lock);
585 spin_unlock(&dentry->d_lock);
586 spin_unlock(&dcache_lock);
590 dentry->d_inode->i_size = 0;
591 dentry->d_inode->i_nlink = 0;
599 static int autofs4_dir_mkdir(struct inode *dir, struct dentry *dentry, int mode)
601 struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb);
602 struct autofs_info *ino = autofs4_dentry_ino(dentry);
605 if ( !autofs4_oz_mode(sbi) )
608 DPRINTK("dentry %p, creating %.*s",
609 dentry, dentry->d_name.len, dentry->d_name.name);
611 ino = autofs4_init_ino(ino, sbi, S_IFDIR | 0555);
615 inode = autofs4_get_inode(dir->i_sb, ino);
616 d_instantiate(dentry, inode);
618 if (dir == dir->i_sb->s_root->d_inode)
619 dentry->d_op = &autofs4_root_dentry_operations;
621 dentry->d_op = &autofs4_dentry_operations;
623 dentry->d_fsdata = ino;
624 ino->dentry = dget(dentry);
627 dir->i_mtime = CURRENT_TIME;
632 /* Get/set timeout ioctl() operation */
633 static inline int autofs4_get_set_timeout(struct autofs_sb_info *sbi,
634 unsigned long __user *p)
637 unsigned long ntimeout;
639 if ( (rv = get_user(ntimeout, p)) ||
640 (rv = put_user(sbi->exp_timeout/HZ, p)) )
643 if ( ntimeout > ULONG_MAX/HZ )
644 sbi->exp_timeout = 0;
646 sbi->exp_timeout = ntimeout * HZ;
651 /* Return protocol version */
652 static inline int autofs4_get_protover(struct autofs_sb_info *sbi, int __user *p)
654 return put_user(sbi->version, p);
657 /* Return protocol sub version */
658 static inline int autofs4_get_protosubver(struct autofs_sb_info *sbi, int __user *p)
660 return put_user(sbi->sub_version, p);
664 * Tells the daemon whether we need to reghost or not. Also, clears
665 * the reghost_needed flag.
667 static inline int autofs4_ask_reghost(struct autofs_sb_info *sbi, int __user *p)
671 DPRINTK("returning %d", sbi->needs_reghost);
673 status = put_user(sbi->needs_reghost, p);
677 sbi->needs_reghost = 0;
682 * Enable / Disable reghosting ioctl() operation
684 static inline int autofs4_toggle_reghost(struct autofs_sb_info *sbi, int __user *p)
689 status = get_user(val, p);
691 DPRINTK("reghost = %d", val);
696 /* turn on/off reghosting, with the val */
697 sbi->reghost_enabled = val;
702 * Tells the daemon whether it can umount the autofs mount.
704 static inline int autofs4_ask_umount(struct vfsmount *mnt, int __user *p)
708 if (may_umount(mnt) == 0)
711 DPRINTK("returning %d", status);
713 status = put_user(status, p);
718 /* Identify autofs4_dentries - this is so we can tell if there's
719 an extra dentry refcount or not. We only hold a refcount on the
720 dentry if its non-negative (ie, d_inode != NULL)
722 int is_autofs4_dentry(struct dentry *dentry)
724 return dentry && dentry->d_inode &&
725 (dentry->d_op == &autofs4_root_dentry_operations ||
726 dentry->d_op == &autofs4_dentry_operations) &&
727 dentry->d_fsdata != NULL;
731 * ioctl()'s on the root directory is the chief method for the daemon to
732 * generate kernel reactions
734 static int autofs4_root_ioctl(struct inode *inode, struct file *filp,
735 unsigned int cmd, unsigned long arg)
737 struct autofs_sb_info *sbi = autofs4_sbi(inode->i_sb);
738 void __user *p = (void __user *)arg;
740 DPRINTK("cmd = 0x%08x, arg = 0x%08lx, sbi = %p, pgrp = %u",
741 cmd,arg,sbi,process_group(current));
743 if ( _IOC_TYPE(cmd) != _IOC_TYPE(AUTOFS_IOC_FIRST) ||
744 _IOC_NR(cmd) - _IOC_NR(AUTOFS_IOC_FIRST) >= AUTOFS_IOC_COUNT )
747 if ( !autofs4_oz_mode(sbi) && !capable(CAP_SYS_ADMIN) )
751 case AUTOFS_IOC_READY: /* Wait queue: go ahead and retry */
752 return autofs4_wait_release(sbi,(autofs_wqt_t)arg,0);
753 case AUTOFS_IOC_FAIL: /* Wait queue: fail with ENOENT */
754 return autofs4_wait_release(sbi,(autofs_wqt_t)arg,-ENOENT);
755 case AUTOFS_IOC_CATATONIC: /* Enter catatonic mode (daemon shutdown) */
756 autofs4_catatonic_mode(sbi);
758 case AUTOFS_IOC_PROTOVER: /* Get protocol version */
759 return autofs4_get_protover(sbi, p);
760 case AUTOFS_IOC_PROTOSUBVER: /* Get protocol sub version */
761 return autofs4_get_protosubver(sbi, p);
762 case AUTOFS_IOC_SETTIMEOUT:
763 return autofs4_get_set_timeout(sbi, p);
765 case AUTOFS_IOC_TOGGLEREGHOST:
766 return autofs4_toggle_reghost(sbi, p);
767 case AUTOFS_IOC_ASKREGHOST:
768 return autofs4_ask_reghost(sbi, p);
770 case AUTOFS_IOC_ASKUMOUNT:
771 return autofs4_ask_umount(filp->f_vfsmnt, p);
773 /* return a single thing to expire */
774 case AUTOFS_IOC_EXPIRE:
775 return autofs4_expire_run(inode->i_sb,filp->f_vfsmnt,sbi, p);
776 /* same as above, but can send multiple expires through pipe */
777 case AUTOFS_IOC_EXPIRE_MULTI:
778 return autofs4_expire_multi(inode->i_sb,filp->f_vfsmnt,sbi, p);