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>
8 * This file is part of the Linux kernel and is made available under
9 * the terms of the GNU General Public License, version 2, or at your
10 * option, any later version, incorporated herein by reference.
12 * ------------------------------------------------------------------------- */
14 #include <linux/errno.h>
15 #include <linux/stat.h>
16 #include <linux/param.h>
17 #include <linux/sched.h>
18 #include <linux/smp_lock.h>
21 static struct dentry *autofs4_dir_lookup(struct inode *,struct dentry *);
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 struct dentry *autofs4_root_lookup(struct inode *,struct dentry *);
29 struct file_operations autofs4_root_operations = {
30 open: dcache_dir_open,
31 release: dcache_dir_close,
32 llseek: dcache_dir_lseek,
33 read: generic_read_dir,
34 readdir: dcache_readdir,
35 fsync: dcache_dir_fsync,
36 ioctl: autofs4_root_ioctl,
39 struct inode_operations autofs4_root_inode_operations = {
40 lookup: autofs4_root_lookup,
41 unlink: autofs4_dir_unlink,
42 symlink: autofs4_dir_symlink,
43 mkdir: autofs4_dir_mkdir,
44 rmdir: autofs4_dir_rmdir,
47 struct inode_operations autofs4_dir_inode_operations = {
48 lookup: autofs4_dir_lookup,
49 unlink: autofs4_dir_unlink,
50 symlink: autofs4_dir_symlink,
51 mkdir: autofs4_dir_mkdir,
52 rmdir: autofs4_dir_rmdir,
55 /* Update usage from here to top of tree, so that scan of
56 top-level directories will give a useful result */
57 static void autofs4_update_usage(struct dentry *dentry)
59 struct dentry *top = dentry->d_sb->s_root;
61 for(; dentry != top; dentry = dentry->d_parent) {
62 struct autofs_info *ino = autofs4_dentry_ino(dentry);
65 update_atime(dentry->d_inode);
66 ino->last_used = jiffies;
71 static int try_to_fill_dentry(struct dentry *dentry,
72 struct super_block *sb,
73 struct autofs_sb_info *sbi)
75 struct autofs_info *de_info = autofs4_dentry_ino(dentry);
78 /* Block on any pending expiry here; invalidate the dentry
79 when expiration is done to trigger mount request with a new
81 if (de_info && (de_info->flags & AUTOFS_INF_EXPIRING)) {
82 DPRINTK(("try_to_fill_entry: waiting for expire %p name=%.*s, flags&PENDING=%s de_info=%p de_info->flags=%x\n",
83 dentry, dentry->d_name.len, dentry->d_name.name,
84 dentry->d_flags & DCACHE_AUTOFS_PENDING?"t":"f",
85 de_info, de_info?de_info->flags:0));
86 status = autofs4_wait(sbi, &dentry->d_name, NFY_NONE);
88 DPRINTK(("try_to_fill_entry: expire done status=%d\n", status));
93 DPRINTK(("try_to_fill_entry: dentry=%p %.*s ino=%p\n",
94 dentry, dentry->d_name.len, dentry->d_name.name, dentry->d_inode));
96 /* Wait for a pending mount, triggering one if there isn't one already */
97 while(dentry->d_inode == NULL) {
98 DPRINTK(("try_to_fill_entry: waiting for mount name=%.*s, de_info=%p de_info->flags=%x\n",
99 dentry->d_name.len, dentry->d_name.name,
100 de_info, de_info?de_info->flags:0));
101 status = autofs4_wait(sbi, &dentry->d_name, NFY_MOUNT);
103 DPRINTK(("try_to_fill_entry: mount done status=%d\n", status));
105 if (status && dentry->d_inode)
106 return 0; /* Try to get the kernel to invalidate this dentry */
108 /* Turn this into a real negative dentry? */
109 if (status == -ENOENT) {
110 dentry->d_time = jiffies + AUTOFS_NEGATIVE_TIMEOUT;
111 dentry->d_flags &= ~DCACHE_AUTOFS_PENDING;
114 /* Return a negative dentry, but leave it "pending" */
119 /* If this is an unused directory that isn't a mount point,
120 bitch at the daemon and fix it in user space */
121 spin_lock(&dcache_lock);
122 if (S_ISDIR(dentry->d_inode->i_mode) &&
123 !d_mountpoint(dentry) &&
124 list_empty(&dentry->d_subdirs)) {
125 DPRINTK(("try_to_fill_entry: mounting existing dir\n"));
126 spin_unlock(&dcache_lock);
127 return autofs4_wait(sbi, &dentry->d_name, NFY_MOUNT) == 0;
129 spin_unlock(&dcache_lock);
131 /* We don't update the usages for the autofs daemon itself, this
132 is necessary for recursive autofs mounts */
133 if (!autofs4_oz_mode(sbi))
134 autofs4_update_usage(dentry);
136 dentry->d_flags &= ~DCACHE_AUTOFS_PENDING;
142 * Revalidate is called on every cache lookup. Some of those
143 * cache lookups may actually happen while the dentry is not
144 * yet completely filled in, and revalidate has to delay such
147 static int autofs4_root_revalidate(struct dentry * dentry, int flags)
149 struct inode * dir = dentry->d_parent->d_inode;
150 struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb);
151 struct autofs_info *ino;
152 int oz_mode = autofs4_oz_mode(sbi);
155 if (autofs4_ispending(dentry)) {
156 if (autofs4_oz_mode(sbi))
159 return try_to_fill_dentry(dentry, dir->i_sb, sbi);
162 /* Negative dentry.. invalidate if "old" */
163 if (dentry->d_inode == NULL)
164 return (dentry->d_time - jiffies <= AUTOFS_NEGATIVE_TIMEOUT);
166 ino = autofs4_dentry_ino(dentry);
168 /* Check for a non-mountpoint directory with no contents */
169 spin_lock(&dcache_lock);
170 if (S_ISDIR(dentry->d_inode->i_mode) &&
171 !d_mountpoint(dentry) &&
172 list_empty(&dentry->d_subdirs)) {
173 DPRINTK(("autofs_root_revalidate: dentry=%p %.*s, emptydir\n",
174 dentry, dentry->d_name.len, dentry->d_name.name));
175 spin_unlock(&dcache_lock);
179 return try_to_fill_dentry(dentry, dir->i_sb, sbi);
181 spin_unlock(&dcache_lock);
183 /* Update the usage list */
185 autofs4_update_usage(dentry);
190 static int autofs4_revalidate(struct dentry *dentry, int flags)
192 struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
194 if (!autofs4_oz_mode(sbi))
195 autofs4_update_usage(dentry);
200 static void autofs4_dentry_release(struct dentry *de)
202 struct autofs_info *inf;
206 DPRINTK(("autofs4_dentry_release: releasing %p\n", de));
208 inf = autofs4_dentry_ino(de);
215 autofs4_free_ino(inf);
221 /* For dentries of directories in the root dir */
222 static struct dentry_operations autofs4_root_dentry_operations = {
223 d_revalidate: autofs4_root_revalidate,
224 d_release: autofs4_dentry_release,
227 /* For other dentries */
228 static struct dentry_operations autofs4_dentry_operations = {
229 d_revalidate: autofs4_revalidate,
230 d_release: autofs4_dentry_release,
233 /* Lookups in non-root dirs never find anything - if it's there, it's
234 already in the dcache */
235 static struct dentry *autofs4_dir_lookup(struct inode *dir, struct dentry *dentry)
238 DPRINTK(("autofs_dir_lookup: ignoring lookup of %.*s/%.*s\n",
239 dentry->d_parent->d_name.len, dentry->d_parent->d_name.name,
240 dentry->d_name.len, dentry->d_name.name));
243 dentry->d_fsdata = NULL;
248 /* Lookups in the root directory */
249 static struct dentry *autofs4_root_lookup(struct inode *dir, struct dentry *dentry)
251 struct autofs_sb_info *sbi;
254 DPRINTK(("autofs_root_lookup: name = %.*s\n",
255 dentry->d_name.len, dentry->d_name.name));
257 if (dentry->d_name.len > NAME_MAX)
258 return ERR_PTR(-ENAMETOOLONG);/* File name too long to exist */
260 sbi = autofs4_sbi(dir->i_sb);
262 oz_mode = autofs4_oz_mode(sbi);
263 DPRINTK(("autofs_lookup: pid = %u, pgrp = %u, catatonic = %d, oz_mode = %d\n",
264 current->pid, current->pgrp, sbi->catatonic, oz_mode));
267 * Mark the dentry incomplete, but add it. This is needed so
268 * that the VFS layer knows about the dentry, and we can count
269 * on catching any lookups through the revalidate.
271 * Let all the hard work be done by the revalidate function that
272 * needs to be able to do this anyway..
274 * We need to do this before we release the directory semaphore.
276 dentry->d_op = &autofs4_root_dentry_operations;
279 dentry->d_flags |= DCACHE_AUTOFS_PENDING;
280 dentry->d_fsdata = NULL;
283 if (dentry->d_op && dentry->d_op->d_revalidate) {
285 (dentry->d_op->d_revalidate)(dentry, 0);
290 * If we are still pending, check if we had to handle
291 * a signal. If so we can force a restart..
293 if (dentry->d_flags & DCACHE_AUTOFS_PENDING) {
294 if (signal_pending(current))
295 return ERR_PTR(-ERESTARTNOINTR);
299 * If this dentry is unhashed, then we shouldn't honour this
300 * lookup even if the dentry is positive. Returning ENOENT here
301 * doesn't do the right thing for all system calls, but it should
302 * be OK for the operations we permit from an autofs.
304 if ( dentry->d_inode && d_unhashed(dentry) )
305 return ERR_PTR(-ENOENT);
310 static int autofs4_dir_symlink(struct inode *dir,
311 struct dentry *dentry,
314 struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb);
315 struct autofs_info *ino = autofs4_dentry_ino(dentry);
319 DPRINTK(("autofs_dir_symlink: %s <- %.*s\n", symname,
320 dentry->d_name.len, dentry->d_name.name));
322 if (!autofs4_oz_mode(sbi))
325 ino = autofs4_init_ino(ino, sbi, S_IFLNK | 0555);
329 ino->size = strlen(symname);
330 ino->u.symlink = cp = kmalloc(ino->size + 1, GFP_KERNEL);
339 inode = autofs4_get_inode(dir->i_sb, ino);
340 d_instantiate(dentry, inode);
342 if (dir == dir->i_sb->s_root->d_inode)
343 dentry->d_op = &autofs4_root_dentry_operations;
345 dentry->d_op = &autofs4_dentry_operations;
347 dentry->d_fsdata = ino;
348 ino->dentry = dget(dentry);
351 dir->i_mtime = CURRENT_TIME;
359 * Normal filesystems would do a "d_delete()" to tell the VFS dcache
360 * that the file no longer exists. However, doing that means that the
361 * VFS layer can turn the dentry into a negative dentry. We don't want
362 * this, because since the unlink is probably the result of an expire.
363 * We simply d_drop it, which allows the dentry lookup to remount it
366 * If a process is blocked on the dentry waiting for the expire to finish,
367 * it will invalidate the dentry and try to mount with a new one.
369 * Also see autofs_dir_rmdir()..
371 static int autofs4_dir_unlink(struct inode *dir, struct dentry *dentry)
373 struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb);
374 struct autofs_info *ino = autofs4_dentry_ino(dentry);
376 /* This allows root to remove symlinks */
377 if ( !autofs4_oz_mode(sbi) && !capable(CAP_SYS_ADMIN) )
382 dentry->d_inode->i_size = 0;
383 dentry->d_inode->i_nlink = 0;
385 dir->i_mtime = CURRENT_TIME;
392 static int autofs4_dir_rmdir(struct inode *dir, struct dentry *dentry)
394 struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb);
395 struct autofs_info *ino = autofs4_dentry_ino(dentry);
397 if (!autofs4_oz_mode(sbi))
400 spin_lock(&dcache_lock);
401 if (!list_empty(&dentry->d_subdirs)) {
402 spin_unlock(&dcache_lock);
405 list_del_init(&dentry->d_hash);
406 spin_unlock(&dcache_lock);
410 dentry->d_inode->i_size = 0;
411 dentry->d_inode->i_nlink = 0;
421 static int autofs4_dir_mkdir(struct inode *dir, struct dentry *dentry, int mode)
423 struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb);
424 struct autofs_info *ino = autofs4_dentry_ino(dentry);
427 if ( !autofs4_oz_mode(sbi) )
430 DPRINTK(("autofs_dir_mkdir: dentry %p, creating %.*s\n",
431 dentry, dentry->d_name.len, dentry->d_name.name));
433 ino = autofs4_init_ino(ino, sbi, S_IFDIR | 0555);
437 inode = autofs4_get_inode(dir->i_sb, ino);
438 d_instantiate(dentry, inode);
440 if (dir == dir->i_sb->s_root->d_inode)
441 dentry->d_op = &autofs4_root_dentry_operations;
443 dentry->d_op = &autofs4_dentry_operations;
445 dentry->d_fsdata = ino;
446 ino->dentry = dget(dentry);
449 dir->i_mtime = CURRENT_TIME;
454 /* Get/set timeout ioctl() operation */
455 static inline int autofs4_get_set_timeout(struct autofs_sb_info *sbi,
459 unsigned long ntimeout;
461 if ( (rv = get_user(ntimeout, p)) ||
462 (rv = put_user(sbi->exp_timeout/HZ, p)) )
465 if ( ntimeout > ULONG_MAX/HZ )
466 sbi->exp_timeout = 0;
468 sbi->exp_timeout = ntimeout * HZ;
473 /* Return protocol version */
474 static inline int autofs4_get_protover(struct autofs_sb_info *sbi, int *p)
476 return put_user(sbi->version, p);
479 /* Identify autofs_dentries - this is so we can tell if there's
480 an extra dentry refcount or not. We only hold a refcount on the
481 dentry if its non-negative (ie, d_inode != NULL)
483 int is_autofs4_dentry(struct dentry *dentry)
485 return dentry && dentry->d_inode &&
486 (dentry->d_op == &autofs4_root_dentry_operations ||
487 dentry->d_op == &autofs4_dentry_operations) &&
488 dentry->d_fsdata != NULL;
492 * ioctl()'s on the root directory is the chief method for the daemon to
493 * generate kernel reactions
495 static int autofs4_root_ioctl(struct inode *inode, struct file *filp,
496 unsigned int cmd, unsigned long arg)
498 struct autofs_sb_info *sbi = autofs4_sbi(inode->i_sb);
500 DPRINTK(("autofs_ioctl: cmd = 0x%08x, arg = 0x%08lx, sbi = %p, pgrp = %u\n",
501 cmd,arg,sbi,current->pgrp));
503 if ( _IOC_TYPE(cmd) != _IOC_TYPE(AUTOFS_IOC_FIRST) ||
504 _IOC_NR(cmd) - _IOC_NR(AUTOFS_IOC_FIRST) >= AUTOFS_IOC_COUNT )
507 if ( !autofs4_oz_mode(sbi) && !capable(CAP_SYS_ADMIN) )
511 case AUTOFS_IOC_READY: /* Wait queue: go ahead and retry */
512 return autofs4_wait_release(sbi,(autofs_wqt_t)arg,0);
513 case AUTOFS_IOC_FAIL: /* Wait queue: fail with ENOENT */
514 return autofs4_wait_release(sbi,(autofs_wqt_t)arg,-ENOENT);
515 case AUTOFS_IOC_CATATONIC: /* Enter catatonic mode (daemon shutdown) */
516 autofs4_catatonic_mode(sbi);
518 case AUTOFS_IOC_PROTOVER: /* Get protocol version */
519 return autofs4_get_protover(sbi, (int *)arg);
520 case AUTOFS_IOC_SETTIMEOUT:
521 return autofs4_get_set_timeout(sbi,(unsigned long *)arg);
523 /* return a single thing to expire */
524 case AUTOFS_IOC_EXPIRE:
525 return autofs4_expire_run(inode->i_sb,filp->f_vfsmnt,sbi,
526 (struct autofs_packet_expire *)arg);
527 /* same as above, but can send multiple expires through pipe */
528 case AUTOFS_IOC_EXPIRE_MULTI:
529 return autofs4_expire_multi(inode->i_sb,filp->f_vfsmnt,sbi,