Merge branch 'fix/asoc' into for-linus
[linux-2.6] / fs / autofs4 / inode.c
1 /* -*- c -*- --------------------------------------------------------------- *
2  *
3  * linux/fs/autofs/inode.c
4  *
5  *  Copyright 1997-1998 Transmeta Corporation -- All Rights Reserved
6  *  Copyright 2005-2006 Ian Kent <raven@themaw.net>
7  *
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.
11  *
12  * ------------------------------------------------------------------------- */
13
14 #include <linux/kernel.h>
15 #include <linux/slab.h>
16 #include <linux/file.h>
17 #include <linux/seq_file.h>
18 #include <linux/pagemap.h>
19 #include <linux/parser.h>
20 #include <linux/bitops.h>
21 #include <linux/magic.h>
22 #include "autofs_i.h"
23 #include <linux/module.h>
24
25 static void ino_lnkfree(struct autofs_info *ino)
26 {
27         if (ino->u.symlink) {
28                 kfree(ino->u.symlink);
29                 ino->u.symlink = NULL;
30         }
31 }
32
33 struct autofs_info *autofs4_init_ino(struct autofs_info *ino,
34                                      struct autofs_sb_info *sbi, mode_t mode)
35 {
36         int reinit = 1;
37
38         if (ino == NULL) {
39                 reinit = 0;
40                 ino = kmalloc(sizeof(*ino), GFP_KERNEL);
41         }
42
43         if (ino == NULL)
44                 return NULL;
45
46         if (!reinit) {
47                 ino->flags = 0;
48                 ino->inode = NULL;
49                 ino->dentry = NULL;
50                 ino->size = 0;
51                 INIT_LIST_HEAD(&ino->active);
52                 INIT_LIST_HEAD(&ino->expiring);
53                 atomic_set(&ino->count, 0);
54         }
55
56         ino->uid = 0;
57         ino->gid = 0;
58         ino->mode = mode;
59         ino->last_used = jiffies;
60
61         ino->sbi = sbi;
62
63         if (reinit && ino->free)
64                 (ino->free)(ino);
65
66         memset(&ino->u, 0, sizeof(ino->u));
67
68         ino->free = NULL;
69
70         if (S_ISLNK(mode))
71                 ino->free = ino_lnkfree;
72
73         return ino;
74 }
75
76 void autofs4_free_ino(struct autofs_info *ino)
77 {
78         struct autofs_info *p_ino;
79
80         if (ino->dentry) {
81                 ino->dentry->d_fsdata = NULL;
82                 if (ino->dentry->d_inode) {
83                         struct dentry *parent = ino->dentry->d_parent;
84                         if (atomic_dec_and_test(&ino->count)) {
85                                 p_ino = autofs4_dentry_ino(parent);
86                                 if (p_ino && parent != ino->dentry)
87                                         atomic_dec(&p_ino->count);
88                         }
89                         dput(ino->dentry);
90                 }
91                 ino->dentry = NULL;
92         }
93         if (ino->free)
94                 (ino->free)(ino);
95         kfree(ino);
96 }
97
98 /*
99  * Deal with the infamous "Busy inodes after umount ..." message.
100  *
101  * Clean up the dentry tree. This happens with autofs if the user
102  * space program goes away due to a SIGKILL, SIGSEGV etc.
103  */
104 static void autofs4_force_release(struct autofs_sb_info *sbi)
105 {
106         struct dentry *this_parent = sbi->sb->s_root;
107         struct list_head *next;
108
109         if (!sbi->sb->s_root)
110                 return;
111
112         spin_lock(&dcache_lock);
113 repeat:
114         next = this_parent->d_subdirs.next;
115 resume:
116         while (next != &this_parent->d_subdirs) {
117                 struct dentry *dentry = list_entry(next, struct dentry, d_u.d_child);
118
119                 /* Negative dentry - don`t care */
120                 if (!simple_positive(dentry)) {
121                         next = next->next;
122                         continue;
123                 }
124
125                 if (!list_empty(&dentry->d_subdirs)) {
126                         this_parent = dentry;
127                         goto repeat;
128                 }
129
130                 next = next->next;
131                 spin_unlock(&dcache_lock);
132
133                 DPRINTK("dentry %p %.*s",
134                         dentry, (int)dentry->d_name.len, dentry->d_name.name);
135
136                 dput(dentry);
137                 spin_lock(&dcache_lock);
138         }
139
140         if (this_parent != sbi->sb->s_root) {
141                 struct dentry *dentry = this_parent;
142
143                 next = this_parent->d_u.d_child.next;
144                 this_parent = this_parent->d_parent;
145                 spin_unlock(&dcache_lock);
146                 DPRINTK("parent dentry %p %.*s",
147                         dentry, (int)dentry->d_name.len, dentry->d_name.name);
148                 dput(dentry);
149                 spin_lock(&dcache_lock);
150                 goto resume;
151         }
152         spin_unlock(&dcache_lock);
153 }
154
155 void autofs4_kill_sb(struct super_block *sb)
156 {
157         struct autofs_sb_info *sbi = autofs4_sbi(sb);
158
159         /*
160          * In the event of a failure in get_sb_nodev the superblock
161          * info is not present so nothing else has been setup, so
162          * just call kill_anon_super when we are called from
163          * deactivate_super.
164          */
165         if (!sbi)
166                 goto out_kill_sb;
167
168         /* Free wait queues, close pipe */
169         autofs4_catatonic_mode(sbi);
170
171         /* Clean up and release dangling references */
172         autofs4_force_release(sbi);
173
174         sb->s_fs_info = NULL;
175         kfree(sbi);
176
177 out_kill_sb:
178         DPRINTK("shutting down");
179         kill_anon_super(sb);
180 }
181
182 static int autofs4_show_options(struct seq_file *m, struct vfsmount *mnt)
183 {
184         struct autofs_sb_info *sbi = autofs4_sbi(mnt->mnt_sb);
185         struct inode *root_inode = mnt->mnt_sb->s_root->d_inode;
186
187         if (!sbi)
188                 return 0;
189
190         seq_printf(m, ",fd=%d", sbi->pipefd);
191         if (root_inode->i_uid != 0)
192                 seq_printf(m, ",uid=%u", root_inode->i_uid);
193         if (root_inode->i_gid != 0)
194                 seq_printf(m, ",gid=%u", root_inode->i_gid);
195         seq_printf(m, ",pgrp=%d", sbi->oz_pgrp);
196         seq_printf(m, ",timeout=%lu", sbi->exp_timeout/HZ);
197         seq_printf(m, ",minproto=%d", sbi->min_proto);
198         seq_printf(m, ",maxproto=%d", sbi->max_proto);
199
200         if (autofs_type_offset(sbi->type))
201                 seq_printf(m, ",offset");
202         else if (autofs_type_direct(sbi->type))
203                 seq_printf(m, ",direct");
204         else
205                 seq_printf(m, ",indirect");
206
207         return 0;
208 }
209
210 static const struct super_operations autofs4_sops = {
211         .statfs         = simple_statfs,
212         .show_options   = autofs4_show_options,
213 };
214
215 enum {Opt_err, Opt_fd, Opt_uid, Opt_gid, Opt_pgrp, Opt_minproto, Opt_maxproto,
216         Opt_indirect, Opt_direct, Opt_offset};
217
218 static const match_table_t tokens = {
219         {Opt_fd, "fd=%u"},
220         {Opt_uid, "uid=%u"},
221         {Opt_gid, "gid=%u"},
222         {Opt_pgrp, "pgrp=%u"},
223         {Opt_minproto, "minproto=%u"},
224         {Opt_maxproto, "maxproto=%u"},
225         {Opt_indirect, "indirect"},
226         {Opt_direct, "direct"},
227         {Opt_offset, "offset"},
228         {Opt_err, NULL}
229 };
230
231 static int parse_options(char *options, int *pipefd, uid_t *uid, gid_t *gid,
232                 pid_t *pgrp, unsigned int *type, int *minproto, int *maxproto)
233 {
234         char *p;
235         substring_t args[MAX_OPT_ARGS];
236         int option;
237
238         *uid = current_uid();
239         *gid = current_gid();
240         *pgrp = task_pgrp_nr(current);
241
242         *minproto = AUTOFS_MIN_PROTO_VERSION;
243         *maxproto = AUTOFS_MAX_PROTO_VERSION;
244
245         *pipefd = -1;
246
247         if (!options)
248                 return 1;
249
250         while ((p = strsep(&options, ",")) != NULL) {
251                 int token;
252                 if (!*p)
253                         continue;
254
255                 token = match_token(p, tokens, args);
256                 switch (token) {
257                 case Opt_fd:
258                         if (match_int(args, pipefd))
259                                 return 1;
260                         break;
261                 case Opt_uid:
262                         if (match_int(args, &option))
263                                 return 1;
264                         *uid = option;
265                         break;
266                 case Opt_gid:
267                         if (match_int(args, &option))
268                                 return 1;
269                         *gid = option;
270                         break;
271                 case Opt_pgrp:
272                         if (match_int(args, &option))
273                                 return 1;
274                         *pgrp = option;
275                         break;
276                 case Opt_minproto:
277                         if (match_int(args, &option))
278                                 return 1;
279                         *minproto = option;
280                         break;
281                 case Opt_maxproto:
282                         if (match_int(args, &option))
283                                 return 1;
284                         *maxproto = option;
285                         break;
286                 case Opt_indirect:
287                         set_autofs_type_indirect(type);
288                         break;
289                 case Opt_direct:
290                         set_autofs_type_direct(type);
291                         break;
292                 case Opt_offset:
293                         set_autofs_type_offset(type);
294                         break;
295                 default:
296                         return 1;
297                 }
298         }
299         return (*pipefd < 0);
300 }
301
302 static struct autofs_info *autofs4_mkroot(struct autofs_sb_info *sbi)
303 {
304         struct autofs_info *ino;
305
306         ino = autofs4_init_ino(NULL, sbi, S_IFDIR | 0755);
307         if (!ino)
308                 return NULL;
309
310         return ino;
311 }
312
313 static const struct dentry_operations autofs4_sb_dentry_operations = {
314         .d_release      = autofs4_dentry_release,
315 };
316
317 int autofs4_fill_super(struct super_block *s, void *data, int silent)
318 {
319         struct inode * root_inode;
320         struct dentry * root;
321         struct file * pipe;
322         int pipefd;
323         struct autofs_sb_info *sbi;
324         struct autofs_info *ino;
325
326         sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
327         if (!sbi)
328                 goto fail_unlock;
329         DPRINTK("starting up, sbi = %p",sbi);
330
331         s->s_fs_info = sbi;
332         sbi->magic = AUTOFS_SBI_MAGIC;
333         sbi->pipefd = -1;
334         sbi->pipe = NULL;
335         sbi->catatonic = 1;
336         sbi->exp_timeout = 0;
337         sbi->oz_pgrp = task_pgrp_nr(current);
338         sbi->sb = s;
339         sbi->version = 0;
340         sbi->sub_version = 0;
341         set_autofs_type_indirect(&sbi->type);
342         sbi->min_proto = 0;
343         sbi->max_proto = 0;
344         mutex_init(&sbi->wq_mutex);
345         spin_lock_init(&sbi->fs_lock);
346         sbi->queues = NULL;
347         spin_lock_init(&sbi->lookup_lock);
348         INIT_LIST_HEAD(&sbi->active_list);
349         INIT_LIST_HEAD(&sbi->expiring_list);
350         s->s_blocksize = 1024;
351         s->s_blocksize_bits = 10;
352         s->s_magic = AUTOFS_SUPER_MAGIC;
353         s->s_op = &autofs4_sops;
354         s->s_time_gran = 1;
355
356         /*
357          * Get the root inode and dentry, but defer checking for errors.
358          */
359         ino = autofs4_mkroot(sbi);
360         if (!ino)
361                 goto fail_free;
362         root_inode = autofs4_get_inode(s, ino);
363         if (!root_inode)
364                 goto fail_ino;
365
366         root = d_alloc_root(root_inode);
367         if (!root)
368                 goto fail_iput;
369         pipe = NULL;
370
371         root->d_op = &autofs4_sb_dentry_operations;
372         root->d_fsdata = ino;
373
374         /* Can this call block? */
375         if (parse_options(data, &pipefd, &root_inode->i_uid, &root_inode->i_gid,
376                                 &sbi->oz_pgrp, &sbi->type, &sbi->min_proto,
377                                 &sbi->max_proto)) {
378                 printk("autofs: called with bogus options\n");
379                 goto fail_dput;
380         }
381
382         root_inode->i_fop = &autofs4_root_operations;
383         root_inode->i_op = autofs_type_trigger(sbi->type) ?
384                         &autofs4_direct_root_inode_operations :
385                         &autofs4_indirect_root_inode_operations;
386
387         /* Couldn't this be tested earlier? */
388         if (sbi->max_proto < AUTOFS_MIN_PROTO_VERSION ||
389             sbi->min_proto > AUTOFS_MAX_PROTO_VERSION) {
390                 printk("autofs: kernel does not match daemon version "
391                        "daemon (%d, %d) kernel (%d, %d)\n",
392                         sbi->min_proto, sbi->max_proto,
393                         AUTOFS_MIN_PROTO_VERSION, AUTOFS_MAX_PROTO_VERSION);
394                 goto fail_dput;
395         }
396
397         /* Establish highest kernel protocol version */
398         if (sbi->max_proto > AUTOFS_MAX_PROTO_VERSION)
399                 sbi->version = AUTOFS_MAX_PROTO_VERSION;
400         else
401                 sbi->version = sbi->max_proto;
402         sbi->sub_version = AUTOFS_PROTO_SUBVERSION;
403
404         DPRINTK("pipe fd = %d, pgrp = %u", pipefd, sbi->oz_pgrp);
405         pipe = fget(pipefd);
406         
407         if (!pipe) {
408                 printk("autofs: could not open pipe file descriptor\n");
409                 goto fail_dput;
410         }
411         if (!pipe->f_op || !pipe->f_op->write)
412                 goto fail_fput;
413         sbi->pipe = pipe;
414         sbi->pipefd = pipefd;
415         sbi->catatonic = 0;
416
417         /*
418          * Success! Install the root dentry now to indicate completion.
419          */
420         s->s_root = root;
421         return 0;
422         
423         /*
424          * Failure ... clean up.
425          */
426 fail_fput:
427         printk("autofs: pipe file descriptor does not contain proper ops\n");
428         fput(pipe);
429         /* fall through */
430 fail_dput:
431         dput(root);
432         goto fail_free;
433 fail_iput:
434         printk("autofs: get root dentry failed\n");
435         iput(root_inode);
436 fail_ino:
437         kfree(ino);
438 fail_free:
439         kfree(sbi);
440         s->s_fs_info = NULL;
441 fail_unlock:
442         return -EINVAL;
443 }
444
445 struct inode *autofs4_get_inode(struct super_block *sb,
446                                 struct autofs_info *inf)
447 {
448         struct inode *inode = new_inode(sb);
449
450         if (inode == NULL)
451                 return NULL;
452
453         inf->inode = inode;
454         inode->i_mode = inf->mode;
455         if (sb->s_root) {
456                 inode->i_uid = sb->s_root->d_inode->i_uid;
457                 inode->i_gid = sb->s_root->d_inode->i_gid;
458         }
459         inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
460
461         if (S_ISDIR(inf->mode)) {
462                 inode->i_nlink = 2;
463                 inode->i_op = &autofs4_dir_inode_operations;
464                 inode->i_fop = &autofs4_dir_operations;
465         } else if (S_ISLNK(inf->mode)) {
466                 inode->i_size = inf->size;
467                 inode->i_op = &autofs4_symlink_inode_operations;
468         }
469
470         return inode;
471 }