[PATCH] Fix 2.6.21 rfcomm lockups
[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/smp_lock.h>
22 #include <linux/magic.h>
23 #include "autofs_i.h"
24 #include <linux/module.h>
25
26 static void ino_lnkfree(struct autofs_info *ino)
27 {
28         kfree(ino->u.symlink);
29         ino->u.symlink = NULL;
30 }
31
32 struct autofs_info *autofs4_init_ino(struct autofs_info *ino,
33                                      struct autofs_sb_info *sbi, mode_t mode)
34 {
35         int reinit = 1;
36
37         if (ino == NULL) {
38                 reinit = 0;
39                 ino = kmalloc(sizeof(*ino), GFP_KERNEL);
40         }
41
42         if (ino == NULL)
43                 return NULL;
44
45         ino->flags = 0;
46         ino->mode = mode;
47         ino->inode = NULL;
48         ino->dentry = NULL;
49         ino->size = 0;
50
51         INIT_LIST_HEAD(&ino->rehash);
52
53         ino->last_used = jiffies;
54         atomic_set(&ino->count, 0);
55
56         ino->sbi = sbi;
57
58         if (reinit && ino->free)
59                 (ino->free)(ino);
60
61         memset(&ino->u, 0, sizeof(ino->u));
62
63         ino->free = NULL;
64
65         if (S_ISLNK(mode))
66                 ino->free = ino_lnkfree;
67
68         return ino;
69 }
70
71 void autofs4_free_ino(struct autofs_info *ino)
72 {
73         struct autofs_info *p_ino;
74
75         if (ino->dentry) {
76                 ino->dentry->d_fsdata = NULL;
77                 if (ino->dentry->d_inode) {
78                         struct dentry *parent = ino->dentry->d_parent;
79                         if (atomic_dec_and_test(&ino->count)) {
80                                 p_ino = autofs4_dentry_ino(parent);
81                                 if (p_ino && parent != ino->dentry)
82                                         atomic_dec(&p_ino->count);
83                         }
84                         dput(ino->dentry);
85                 }
86                 ino->dentry = NULL;
87         }
88         if (ino->free)
89                 (ino->free)(ino);
90         kfree(ino);
91 }
92
93 /*
94  * Deal with the infamous "Busy inodes after umount ..." message.
95  *
96  * Clean up the dentry tree. This happens with autofs if the user
97  * space program goes away due to a SIGKILL, SIGSEGV etc.
98  */
99 static void autofs4_force_release(struct autofs_sb_info *sbi)
100 {
101         struct dentry *this_parent = sbi->sb->s_root;
102         struct list_head *next;
103
104         if (!sbi->sb->s_root)
105                 return;
106
107         spin_lock(&dcache_lock);
108 repeat:
109         next = this_parent->d_subdirs.next;
110 resume:
111         while (next != &this_parent->d_subdirs) {
112                 struct dentry *dentry = list_entry(next, struct dentry, d_u.d_child);
113
114                 /* Negative dentry - don`t care */
115                 if (!simple_positive(dentry)) {
116                         next = next->next;
117                         continue;
118                 }
119
120                 if (!list_empty(&dentry->d_subdirs)) {
121                         this_parent = dentry;
122                         goto repeat;
123                 }
124
125                 next = next->next;
126                 spin_unlock(&dcache_lock);
127
128                 DPRINTK("dentry %p %.*s",
129                         dentry, (int)dentry->d_name.len, dentry->d_name.name);
130
131                 dput(dentry);
132                 spin_lock(&dcache_lock);
133         }
134
135         if (this_parent != sbi->sb->s_root) {
136                 struct dentry *dentry = this_parent;
137
138                 next = this_parent->d_u.d_child.next;
139                 this_parent = this_parent->d_parent;
140                 spin_unlock(&dcache_lock);
141                 DPRINTK("parent dentry %p %.*s",
142                         dentry, (int)dentry->d_name.len, dentry->d_name.name);
143                 dput(dentry);
144                 spin_lock(&dcache_lock);
145                 goto resume;
146         }
147         spin_unlock(&dcache_lock);
148 }
149
150 void autofs4_kill_sb(struct super_block *sb)
151 {
152         struct autofs_sb_info *sbi = autofs4_sbi(sb);
153
154         /*
155          * In the event of a failure in get_sb_nodev the superblock
156          * info is not present so nothing else has been setup, so
157          * just call kill_anon_super when we are called from
158          * deactivate_super.
159          */
160         if (!sbi)
161                 goto out_kill_sb;
162
163         if (!sbi->catatonic)
164                 autofs4_catatonic_mode(sbi); /* Free wait queues, close pipe */
165
166         /* Clean up and release dangling references */
167         autofs4_force_release(sbi);
168
169         sb->s_fs_info = NULL;
170         kfree(sbi);
171
172 out_kill_sb:
173         DPRINTK("shutting down");
174         kill_anon_super(sb);
175 }
176
177 static int autofs4_show_options(struct seq_file *m, struct vfsmount *mnt)
178 {
179         struct autofs_sb_info *sbi = autofs4_sbi(mnt->mnt_sb);
180
181         if (!sbi)
182                 return 0;
183
184         seq_printf(m, ",fd=%d", sbi->pipefd);
185         seq_printf(m, ",pgrp=%d", sbi->oz_pgrp);
186         seq_printf(m, ",timeout=%lu", sbi->exp_timeout/HZ);
187         seq_printf(m, ",minproto=%d", sbi->min_proto);
188         seq_printf(m, ",maxproto=%d", sbi->max_proto);
189
190         if (sbi->type & AUTOFS_TYPE_OFFSET)
191                 seq_printf(m, ",offset");
192         else if (sbi->type & AUTOFS_TYPE_DIRECT)
193                 seq_printf(m, ",direct");
194         else
195                 seq_printf(m, ",indirect");
196
197         return 0;
198 }
199
200 static const struct super_operations autofs4_sops = {
201         .statfs         = simple_statfs,
202         .show_options   = autofs4_show_options,
203 };
204
205 enum {Opt_err, Opt_fd, Opt_uid, Opt_gid, Opt_pgrp, Opt_minproto, Opt_maxproto,
206         Opt_indirect, Opt_direct, Opt_offset};
207
208 static match_table_t tokens = {
209         {Opt_fd, "fd=%u"},
210         {Opt_uid, "uid=%u"},
211         {Opt_gid, "gid=%u"},
212         {Opt_pgrp, "pgrp=%u"},
213         {Opt_minproto, "minproto=%u"},
214         {Opt_maxproto, "maxproto=%u"},
215         {Opt_indirect, "indirect"},
216         {Opt_direct, "direct"},
217         {Opt_offset, "offset"},
218         {Opt_err, NULL}
219 };
220
221 static int parse_options(char *options, int *pipefd, uid_t *uid, gid_t *gid,
222                          pid_t *pgrp, unsigned int *type,
223                          int *minproto, int *maxproto)
224 {
225         char *p;
226         substring_t args[MAX_OPT_ARGS];
227         int option;
228
229         *uid = current->uid;
230         *gid = current->gid;
231         *pgrp = process_group(current);
232
233         *minproto = AUTOFS_MIN_PROTO_VERSION;
234         *maxproto = AUTOFS_MAX_PROTO_VERSION;
235
236         *pipefd = -1;
237
238         if (!options)
239                 return 1;
240
241         while ((p = strsep(&options, ",")) != NULL) {
242                 int token;
243                 if (!*p)
244                         continue;
245
246                 token = match_token(p, tokens, args);
247                 switch (token) {
248                 case Opt_fd:
249                         if (match_int(args, pipefd))
250                                 return 1;
251                         break;
252                 case Opt_uid:
253                         if (match_int(args, &option))
254                                 return 1;
255                         *uid = option;
256                         break;
257                 case Opt_gid:
258                         if (match_int(args, &option))
259                                 return 1;
260                         *gid = option;
261                         break;
262                 case Opt_pgrp:
263                         if (match_int(args, &option))
264                                 return 1;
265                         *pgrp = option;
266                         break;
267                 case Opt_minproto:
268                         if (match_int(args, &option))
269                                 return 1;
270                         *minproto = option;
271                         break;
272                 case Opt_maxproto:
273                         if (match_int(args, &option))
274                                 return 1;
275                         *maxproto = option;
276                         break;
277                 case Opt_indirect:
278                         *type = AUTOFS_TYPE_INDIRECT;
279                         break;
280                 case Opt_direct:
281                         *type = AUTOFS_TYPE_DIRECT;
282                         break;
283                 case Opt_offset:
284                         *type = AUTOFS_TYPE_DIRECT | AUTOFS_TYPE_OFFSET;
285                         break;
286                 default:
287                         return 1;
288                 }
289         }
290         return (*pipefd < 0);
291 }
292
293 static struct autofs_info *autofs4_mkroot(struct autofs_sb_info *sbi)
294 {
295         struct autofs_info *ino;
296
297         ino = autofs4_init_ino(NULL, sbi, S_IFDIR | 0755);
298         if (!ino)
299                 return NULL;
300
301         return ino;
302 }
303
304 static struct dentry_operations autofs4_sb_dentry_operations = {
305         .d_release      = autofs4_dentry_release,
306 };
307
308 int autofs4_fill_super(struct super_block *s, void *data, int silent)
309 {
310         struct inode * root_inode;
311         struct dentry * root;
312         struct file * pipe;
313         int pipefd;
314         struct autofs_sb_info *sbi;
315         struct autofs_info *ino;
316
317         sbi = kmalloc(sizeof(*sbi), GFP_KERNEL);
318         if ( !sbi )
319                 goto fail_unlock;
320         DPRINTK("starting up, sbi = %p",sbi);
321
322         memset(sbi, 0, sizeof(*sbi));
323
324         s->s_fs_info = sbi;
325         sbi->magic = AUTOFS_SBI_MAGIC;
326         sbi->pipefd = -1;
327         sbi->pipe = NULL;
328         sbi->catatonic = 1;
329         sbi->exp_timeout = 0;
330         sbi->oz_pgrp = process_group(current);
331         sbi->sb = s;
332         sbi->version = 0;
333         sbi->sub_version = 0;
334         sbi->type = 0;
335         sbi->min_proto = 0;
336         sbi->max_proto = 0;
337         mutex_init(&sbi->wq_mutex);
338         spin_lock_init(&sbi->fs_lock);
339         sbi->queues = NULL;
340         spin_lock_init(&sbi->rehash_lock);
341         INIT_LIST_HEAD(&sbi->rehash_list);
342         s->s_blocksize = 1024;
343         s->s_blocksize_bits = 10;
344         s->s_magic = AUTOFS_SUPER_MAGIC;
345         s->s_op = &autofs4_sops;
346         s->s_time_gran = 1;
347
348         /*
349          * Get the root inode and dentry, but defer checking for errors.
350          */
351         ino = autofs4_mkroot(sbi);
352         if (!ino)
353                 goto fail_free;
354         root_inode = autofs4_get_inode(s, ino);
355         if (!root_inode)
356                 goto fail_ino;
357
358         root = d_alloc_root(root_inode);
359         if (!root)
360                 goto fail_iput;
361         pipe = NULL;
362
363         root->d_op = &autofs4_sb_dentry_operations;
364         root->d_fsdata = ino;
365
366         /* Can this call block? */
367         if (parse_options(data, &pipefd,
368                           &root_inode->i_uid, &root_inode->i_gid,
369                           &sbi->oz_pgrp, &sbi->type,
370                           &sbi->min_proto, &sbi->max_proto)) {
371                 printk("autofs: called with bogus options\n");
372                 goto fail_dput;
373         }
374
375         root_inode->i_fop = &autofs4_root_operations;
376         root_inode->i_op = sbi->type & AUTOFS_TYPE_DIRECT ?
377                         &autofs4_direct_root_inode_operations :
378                         &autofs4_indirect_root_inode_operations;
379
380         /* Couldn't this be tested earlier? */
381         if (sbi->max_proto < AUTOFS_MIN_PROTO_VERSION ||
382             sbi->min_proto > AUTOFS_MAX_PROTO_VERSION) {
383                 printk("autofs: kernel does not match daemon version "
384                        "daemon (%d, %d) kernel (%d, %d)\n",
385                         sbi->min_proto, sbi->max_proto,
386                         AUTOFS_MIN_PROTO_VERSION, AUTOFS_MAX_PROTO_VERSION);
387                 goto fail_dput;
388         }
389
390         /* Establish highest kernel protocol version */
391         if (sbi->max_proto > AUTOFS_MAX_PROTO_VERSION)
392                 sbi->version = AUTOFS_MAX_PROTO_VERSION;
393         else
394                 sbi->version = sbi->max_proto;
395         sbi->sub_version = AUTOFS_PROTO_SUBVERSION;
396
397         DPRINTK("pipe fd = %d, pgrp = %u", pipefd, sbi->oz_pgrp);
398         pipe = fget(pipefd);
399         
400         if ( !pipe ) {
401                 printk("autofs: could not open pipe file descriptor\n");
402                 goto fail_dput;
403         }
404         if ( !pipe->f_op || !pipe->f_op->write )
405                 goto fail_fput;
406         sbi->pipe = pipe;
407         sbi->pipefd = pipefd;
408         sbi->catatonic = 0;
409
410         /*
411          * Success! Install the root dentry now to indicate completion.
412          */
413         s->s_root = root;
414         return 0;
415         
416         /*
417          * Failure ... clean up.
418          */
419 fail_fput:
420         printk("autofs: pipe file descriptor does not contain proper ops\n");
421         fput(pipe);
422         /* fall through */
423 fail_dput:
424         dput(root);
425         goto fail_free;
426 fail_iput:
427         printk("autofs: get root dentry failed\n");
428         iput(root_inode);
429 fail_ino:
430         kfree(ino);
431 fail_free:
432         kfree(sbi);
433         s->s_fs_info = NULL;
434 fail_unlock:
435         return -EINVAL;
436 }
437
438 struct inode *autofs4_get_inode(struct super_block *sb,
439                                 struct autofs_info *inf)
440 {
441         struct inode *inode = new_inode(sb);
442
443         if (inode == NULL)
444                 return NULL;
445
446         inf->inode = inode;
447         inode->i_mode = inf->mode;
448         if (sb->s_root) {
449                 inode->i_uid = sb->s_root->d_inode->i_uid;
450                 inode->i_gid = sb->s_root->d_inode->i_gid;
451         } else {
452                 inode->i_uid = 0;
453                 inode->i_gid = 0;
454         }
455         inode->i_blocks = 0;
456         inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
457
458         if (S_ISDIR(inf->mode)) {
459                 inode->i_nlink = 2;
460                 inode->i_op = &autofs4_dir_inode_operations;
461                 inode->i_fop = &autofs4_dir_operations;
462         } else if (S_ISLNK(inf->mode)) {
463                 inode->i_size = inf->size;
464                 inode->i_op = &autofs4_symlink_inode_operations;
465         }
466
467         return inode;
468 }