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 int oz_mode = autofs4_oz_mode(sbi);
154 if (autofs4_ispending(dentry)) {
155 if (autofs4_oz_mode(sbi))
158 return try_to_fill_dentry(dentry, dir->i_sb, sbi);
161 /* Negative dentry.. invalidate if "old" */
162 if (dentry->d_inode == NULL)
163 return (dentry->d_time - jiffies <= AUTOFS_NEGATIVE_TIMEOUT);
165 /* Check for a non-mountpoint directory with no contents */
166 spin_lock(&dcache_lock);
167 if (S_ISDIR(dentry->d_inode->i_mode) &&
168 !d_mountpoint(dentry) &&
169 list_empty(&dentry->d_subdirs)) {
170 DPRINTK(("autofs_root_revalidate: dentry=%p %.*s, emptydir\n",
171 dentry, dentry->d_name.len, dentry->d_name.name));
172 spin_unlock(&dcache_lock);
176 return try_to_fill_dentry(dentry, dir->i_sb, sbi);
178 spin_unlock(&dcache_lock);
180 /* Update the usage list */
182 autofs4_update_usage(dentry);
187 static int autofs4_revalidate(struct dentry *dentry, int flags)
189 struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
191 if (!autofs4_oz_mode(sbi))
192 autofs4_update_usage(dentry);
197 static void autofs4_dentry_release(struct dentry *de)
199 struct autofs_info *inf;
203 DPRINTK(("autofs4_dentry_release: releasing %p\n", de));
205 inf = autofs4_dentry_ino(de);
212 autofs4_free_ino(inf);
218 /* For dentries of directories in the root dir */
219 static struct dentry_operations autofs4_root_dentry_operations = {
220 d_revalidate: autofs4_root_revalidate,
221 d_release: autofs4_dentry_release,
224 /* For other dentries */
225 static struct dentry_operations autofs4_dentry_operations = {
226 d_revalidate: autofs4_revalidate,
227 d_release: autofs4_dentry_release,
230 /* Lookups in non-root dirs never find anything - if it's there, it's
231 already in the dcache */
232 static struct dentry *autofs4_dir_lookup(struct inode *dir, struct dentry *dentry)
235 DPRINTK(("autofs_dir_lookup: ignoring lookup of %.*s/%.*s\n",
236 dentry->d_parent->d_name.len, dentry->d_parent->d_name.name,
237 dentry->d_name.len, dentry->d_name.name));
240 dentry->d_fsdata = NULL;
245 /* Lookups in the root directory */
246 static struct dentry *autofs4_root_lookup(struct inode *dir, struct dentry *dentry)
248 struct autofs_sb_info *sbi;
251 DPRINTK(("autofs_root_lookup: name = %.*s\n",
252 dentry->d_name.len, dentry->d_name.name));
254 if (dentry->d_name.len > NAME_MAX)
255 return ERR_PTR(-ENAMETOOLONG);/* File name too long to exist */
257 sbi = autofs4_sbi(dir->i_sb);
259 oz_mode = autofs4_oz_mode(sbi);
260 DPRINTK(("autofs_lookup: pid = %u, pgrp = %u, catatonic = %d, oz_mode = %d\n",
261 current->pid, current->pgrp, sbi->catatonic, oz_mode));
264 * Mark the dentry incomplete, but add it. This is needed so
265 * that the VFS layer knows about the dentry, and we can count
266 * on catching any lookups through the revalidate.
268 * Let all the hard work be done by the revalidate function that
269 * needs to be able to do this anyway..
271 * We need to do this before we release the directory semaphore.
273 dentry->d_op = &autofs4_root_dentry_operations;
276 dentry->d_flags |= DCACHE_AUTOFS_PENDING;
277 dentry->d_fsdata = NULL;
280 if (dentry->d_op && dentry->d_op->d_revalidate) {
282 (dentry->d_op->d_revalidate)(dentry, 0);
287 * If we are still pending, check if we had to handle
288 * a signal. If so we can force a restart..
290 if (dentry->d_flags & DCACHE_AUTOFS_PENDING) {
291 if (signal_pending(current))
292 return ERR_PTR(-ERESTARTNOINTR);
296 * If this dentry is unhashed, then we shouldn't honour this
297 * lookup even if the dentry is positive. Returning ENOENT here
298 * doesn't do the right thing for all system calls, but it should
299 * be OK for the operations we permit from an autofs.
301 if ( dentry->d_inode && d_unhashed(dentry) )
302 return ERR_PTR(-ENOENT);
307 static int autofs4_dir_symlink(struct inode *dir,
308 struct dentry *dentry,
311 struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb);
312 struct autofs_info *ino = autofs4_dentry_ino(dentry);
316 DPRINTK(("autofs_dir_symlink: %s <- %.*s\n", symname,
317 dentry->d_name.len, dentry->d_name.name));
319 if (!autofs4_oz_mode(sbi))
322 ino = autofs4_init_ino(ino, sbi, S_IFLNK | 0555);
326 ino->size = strlen(symname);
327 ino->u.symlink = cp = kmalloc(ino->size + 1, GFP_KERNEL);
336 inode = autofs4_get_inode(dir->i_sb, ino);
337 d_instantiate(dentry, inode);
339 if (dir == dir->i_sb->s_root->d_inode)
340 dentry->d_op = &autofs4_root_dentry_operations;
342 dentry->d_op = &autofs4_dentry_operations;
344 dentry->d_fsdata = ino;
345 ino->dentry = dget(dentry);
348 dir->i_mtime = CURRENT_TIME;
356 * Normal filesystems would do a "d_delete()" to tell the VFS dcache
357 * that the file no longer exists. However, doing that means that the
358 * VFS layer can turn the dentry into a negative dentry. We don't want
359 * this, because since the unlink is probably the result of an expire.
360 * We simply d_drop it, which allows the dentry lookup to remount it
363 * If a process is blocked on the dentry waiting for the expire to finish,
364 * it will invalidate the dentry and try to mount with a new one.
366 * Also see autofs_dir_rmdir()..
368 static int autofs4_dir_unlink(struct inode *dir, struct dentry *dentry)
370 struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb);
371 struct autofs_info *ino = autofs4_dentry_ino(dentry);
373 /* This allows root to remove symlinks */
374 if ( !autofs4_oz_mode(sbi) && !capable(CAP_SYS_ADMIN) )
379 dentry->d_inode->i_size = 0;
380 dentry->d_inode->i_nlink = 0;
382 dir->i_mtime = CURRENT_TIME;
389 static int autofs4_dir_rmdir(struct inode *dir, struct dentry *dentry)
391 struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb);
392 struct autofs_info *ino = autofs4_dentry_ino(dentry);
394 if (!autofs4_oz_mode(sbi))
397 spin_lock(&dcache_lock);
398 if (!list_empty(&dentry->d_subdirs)) {
399 spin_unlock(&dcache_lock);
402 list_del_init(&dentry->d_hash);
403 spin_unlock(&dcache_lock);
407 dentry->d_inode->i_size = 0;
408 dentry->d_inode->i_nlink = 0;
418 static int autofs4_dir_mkdir(struct inode *dir, struct dentry *dentry, int mode)
420 struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb);
421 struct autofs_info *ino = autofs4_dentry_ino(dentry);
424 if ( !autofs4_oz_mode(sbi) )
427 DPRINTK(("autofs_dir_mkdir: dentry %p, creating %.*s\n",
428 dentry, dentry->d_name.len, dentry->d_name.name));
430 ino = autofs4_init_ino(ino, sbi, S_IFDIR | 0555);
434 inode = autofs4_get_inode(dir->i_sb, ino);
435 d_instantiate(dentry, inode);
437 if (dir == dir->i_sb->s_root->d_inode)
438 dentry->d_op = &autofs4_root_dentry_operations;
440 dentry->d_op = &autofs4_dentry_operations;
442 dentry->d_fsdata = ino;
443 ino->dentry = dget(dentry);
446 dir->i_mtime = CURRENT_TIME;
451 /* Get/set timeout ioctl() operation */
452 static inline int autofs4_get_set_timeout(struct autofs_sb_info *sbi,
456 unsigned long ntimeout;
458 if ( (rv = get_user(ntimeout, p)) ||
459 (rv = put_user(sbi->exp_timeout/HZ, p)) )
462 if ( ntimeout > ULONG_MAX/HZ )
463 sbi->exp_timeout = 0;
465 sbi->exp_timeout = ntimeout * HZ;
470 /* Return protocol version */
471 static inline int autofs4_get_protover(struct autofs_sb_info *sbi, int *p)
473 return put_user(sbi->version, p);
476 /* Identify autofs_dentries - this is so we can tell if there's
477 an extra dentry refcount or not. We only hold a refcount on the
478 dentry if its non-negative (ie, d_inode != NULL)
480 int is_autofs4_dentry(struct dentry *dentry)
482 return dentry && dentry->d_inode &&
483 (dentry->d_op == &autofs4_root_dentry_operations ||
484 dentry->d_op == &autofs4_dentry_operations) &&
485 dentry->d_fsdata != NULL;
489 * ioctl()'s on the root directory is the chief method for the daemon to
490 * generate kernel reactions
492 static int autofs4_root_ioctl(struct inode *inode, struct file *filp,
493 unsigned int cmd, unsigned long arg)
495 struct autofs_sb_info *sbi = autofs4_sbi(inode->i_sb);
497 DPRINTK(("autofs_ioctl: cmd = 0x%08x, arg = 0x%08lx, sbi = %p, pgrp = %u\n",
498 cmd,arg,sbi,current->pgrp));
500 if ( _IOC_TYPE(cmd) != _IOC_TYPE(AUTOFS_IOC_FIRST) ||
501 _IOC_NR(cmd) - _IOC_NR(AUTOFS_IOC_FIRST) >= AUTOFS_IOC_COUNT )
504 if ( !autofs4_oz_mode(sbi) && !capable(CAP_SYS_ADMIN) )
508 case AUTOFS_IOC_READY: /* Wait queue: go ahead and retry */
509 return autofs4_wait_release(sbi,(autofs_wqt_t)arg,0);
510 case AUTOFS_IOC_FAIL: /* Wait queue: fail with ENOENT */
511 return autofs4_wait_release(sbi,(autofs_wqt_t)arg,-ENOENT);
512 case AUTOFS_IOC_CATATONIC: /* Enter catatonic mode (daemon shutdown) */
513 autofs4_catatonic_mode(sbi);
515 case AUTOFS_IOC_PROTOVER: /* Get protocol version */
516 return autofs4_get_protover(sbi, (int *)arg);
517 case AUTOFS_IOC_SETTIMEOUT:
518 return autofs4_get_set_timeout(sbi,(unsigned long *)arg);
520 /* return a single thing to expire */
521 case AUTOFS_IOC_EXPIRE:
522 return autofs4_expire_run(inode->i_sb,filp->f_vfsmnt,sbi,
523 (struct autofs_packet_expire *)arg);
524 /* same as above, but can send multiple expires through pipe */
525 case AUTOFS_IOC_EXPIRE_MULTI:
526 return autofs4_expire_multi(inode->i_sb,filp->f_vfsmnt,sbi,