Merge master.kernel.org:/home/rmk/linux-2.6-serial
[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 "autofs_i.h"
23 #include <linux/module.h>
24
25 static void ino_lnkfree(struct autofs_info *ino)
26 {
27         kfree(ino->u.symlink);
28         ino->u.symlink = NULL;
29 }
30
31 struct autofs_info *autofs4_init_ino(struct autofs_info *ino,
32                                      struct autofs_sb_info *sbi, mode_t mode)
33 {
34         int reinit = 1;
35
36         if (ino == NULL) {
37                 reinit = 0;
38                 ino = kmalloc(sizeof(*ino), GFP_KERNEL);
39         }
40
41         if (ino == NULL)
42                 return NULL;
43
44         ino->flags = 0;
45         ino->mode = mode;
46         ino->inode = NULL;
47         ino->dentry = NULL;
48         ino->size = 0;
49
50         ino->last_used = jiffies;
51         atomic_set(&ino->count, 0);
52
53         ino->sbi = sbi;
54
55         if (reinit && ino->free)
56                 (ino->free)(ino);
57
58         memset(&ino->u, 0, sizeof(ino->u));
59
60         ino->free = NULL;
61
62         if (S_ISLNK(mode))
63                 ino->free = ino_lnkfree;
64
65         return ino;
66 }
67
68 void autofs4_free_ino(struct autofs_info *ino)
69 {
70         struct autofs_info *p_ino;
71
72         if (ino->dentry) {
73                 ino->dentry->d_fsdata = NULL;
74                 if (ino->dentry->d_inode) {
75                         struct dentry *parent = ino->dentry->d_parent;
76                         if (atomic_dec_and_test(&ino->count)) {
77                                 p_ino = autofs4_dentry_ino(parent);
78                                 if (p_ino && parent != ino->dentry)
79                                         atomic_dec(&p_ino->count);
80                         }
81                         dput(ino->dentry);
82                 }
83                 ino->dentry = NULL;
84         }
85         if (ino->free)
86                 (ino->free)(ino);
87         kfree(ino);
88 }
89
90 /*
91  * Deal with the infamous "Busy inodes after umount ..." message.
92  *
93  * Clean up the dentry tree. This happens with autofs if the user
94  * space program goes away due to a SIGKILL, SIGSEGV etc.
95  */
96 static void autofs4_force_release(struct autofs_sb_info *sbi)
97 {
98         struct dentry *this_parent = sbi->root;
99         struct list_head *next;
100
101         spin_lock(&dcache_lock);
102 repeat:
103         next = this_parent->d_subdirs.next;
104 resume:
105         while (next != &this_parent->d_subdirs) {
106                 struct dentry *dentry = list_entry(next, struct dentry, d_u.d_child);
107
108                 /* Negative dentry - don`t care */
109                 if (!simple_positive(dentry)) {
110                         next = next->next;
111                         continue;
112                 }
113
114                 if (!list_empty(&dentry->d_subdirs)) {
115                         this_parent = dentry;
116                         goto repeat;
117                 }
118
119                 next = next->next;
120                 spin_unlock(&dcache_lock);
121
122                 DPRINTK("dentry %p %.*s",
123                         dentry, (int)dentry->d_name.len, dentry->d_name.name);
124
125                 dput(dentry);
126                 spin_lock(&dcache_lock);
127         }
128
129         if (this_parent != sbi->root) {
130                 struct dentry *dentry = this_parent;
131
132                 next = this_parent->d_u.d_child.next;
133                 this_parent = this_parent->d_parent;
134                 spin_unlock(&dcache_lock);
135                 DPRINTK("parent dentry %p %.*s",
136                         dentry, (int)dentry->d_name.len, dentry->d_name.name);
137                 dput(dentry);
138                 spin_lock(&dcache_lock);
139                 goto resume;
140         }
141         spin_unlock(&dcache_lock);
142
143         dput(sbi->root);
144         sbi->root = NULL;
145         shrink_dcache_sb(sbi->sb);
146
147         return;
148 }
149
150 static void autofs4_put_super(struct super_block *sb)
151 {
152         struct autofs_sb_info *sbi = autofs4_sbi(sb);
153
154         sb->s_fs_info = NULL;
155
156         if ( !sbi->catatonic )
157                 autofs4_catatonic_mode(sbi); /* Free wait queues, close pipe */
158
159         /* Clean up and release dangling references */
160         autofs4_force_release(sbi);
161
162         kfree(sbi);
163
164         DPRINTK("shutting down");
165 }
166
167 static int autofs4_show_options(struct seq_file *m, struct vfsmount *mnt)
168 {
169         struct autofs_sb_info *sbi = autofs4_sbi(mnt->mnt_sb);
170
171         if (!sbi)
172                 return 0;
173
174         seq_printf(m, ",fd=%d", sbi->pipefd);
175         seq_printf(m, ",pgrp=%d", sbi->oz_pgrp);
176         seq_printf(m, ",timeout=%lu", sbi->exp_timeout/HZ);
177         seq_printf(m, ",minproto=%d", sbi->min_proto);
178         seq_printf(m, ",maxproto=%d", sbi->max_proto);
179
180         if (sbi->type & AUTOFS_TYPE_OFFSET)
181                 seq_printf(m, ",offset");
182         else if (sbi->type & AUTOFS_TYPE_DIRECT)
183                 seq_printf(m, ",direct");
184         else
185                 seq_printf(m, ",indirect");
186
187         return 0;
188 }
189
190 static struct super_operations autofs4_sops = {
191         .put_super      = autofs4_put_super,
192         .statfs         = simple_statfs,
193         .show_options   = autofs4_show_options,
194 };
195
196 enum {Opt_err, Opt_fd, Opt_uid, Opt_gid, Opt_pgrp, Opt_minproto, Opt_maxproto,
197         Opt_indirect, Opt_direct, Opt_offset};
198
199 static match_table_t tokens = {
200         {Opt_fd, "fd=%u"},
201         {Opt_uid, "uid=%u"},
202         {Opt_gid, "gid=%u"},
203         {Opt_pgrp, "pgrp=%u"},
204         {Opt_minproto, "minproto=%u"},
205         {Opt_maxproto, "maxproto=%u"},
206         {Opt_indirect, "indirect"},
207         {Opt_direct, "direct"},
208         {Opt_offset, "offset"},
209         {Opt_err, NULL}
210 };
211
212 static int parse_options(char *options, int *pipefd, uid_t *uid, gid_t *gid,
213                          pid_t *pgrp, unsigned int *type,
214                          int *minproto, int *maxproto)
215 {
216         char *p;
217         substring_t args[MAX_OPT_ARGS];
218         int option;
219
220         *uid = current->uid;
221         *gid = current->gid;
222         *pgrp = process_group(current);
223
224         *minproto = AUTOFS_MIN_PROTO_VERSION;
225         *maxproto = AUTOFS_MAX_PROTO_VERSION;
226
227         *pipefd = -1;
228
229         if (!options)
230                 return 1;
231
232         while ((p = strsep(&options, ",")) != NULL) {
233                 int token;
234                 if (!*p)
235                         continue;
236
237                 token = match_token(p, tokens, args);
238                 switch (token) {
239                 case Opt_fd:
240                         if (match_int(args, pipefd))
241                                 return 1;
242                         break;
243                 case Opt_uid:
244                         if (match_int(args, &option))
245                                 return 1;
246                         *uid = option;
247                         break;
248                 case Opt_gid:
249                         if (match_int(args, &option))
250                                 return 1;
251                         *gid = option;
252                         break;
253                 case Opt_pgrp:
254                         if (match_int(args, &option))
255                                 return 1;
256                         *pgrp = option;
257                         break;
258                 case Opt_minproto:
259                         if (match_int(args, &option))
260                                 return 1;
261                         *minproto = option;
262                         break;
263                 case Opt_maxproto:
264                         if (match_int(args, &option))
265                                 return 1;
266                         *maxproto = option;
267                         break;
268                 case Opt_indirect:
269                         *type = AUTOFS_TYPE_INDIRECT;
270                         break;
271                 case Opt_direct:
272                         *type = AUTOFS_TYPE_DIRECT;
273                         break;
274                 case Opt_offset:
275                         *type = AUTOFS_TYPE_DIRECT | AUTOFS_TYPE_OFFSET;
276                         break;
277                 default:
278                         return 1;
279                 }
280         }
281         return (*pipefd < 0);
282 }
283
284 static struct autofs_info *autofs4_mkroot(struct autofs_sb_info *sbi)
285 {
286         struct autofs_info *ino;
287
288         ino = autofs4_init_ino(NULL, sbi, S_IFDIR | 0755);
289         if (!ino)
290                 return NULL;
291
292         return ino;
293 }
294
295 static struct dentry_operations autofs4_sb_dentry_operations = {
296         .d_release      = autofs4_dentry_release,
297 };
298
299 int autofs4_fill_super(struct super_block *s, void *data, int silent)
300 {
301         struct inode * root_inode;
302         struct dentry * root;
303         struct file * pipe;
304         int pipefd;
305         struct autofs_sb_info *sbi;
306         struct autofs_info *ino;
307
308         sbi = (struct autofs_sb_info *) kmalloc(sizeof(*sbi), GFP_KERNEL);
309         if ( !sbi )
310                 goto fail_unlock;
311         DPRINTK("starting up, sbi = %p",sbi);
312
313         memset(sbi, 0, sizeof(*sbi));
314
315         s->s_fs_info = sbi;
316         sbi->magic = AUTOFS_SBI_MAGIC;
317         sbi->root = NULL;
318         sbi->pipefd = -1;
319         sbi->catatonic = 0;
320         sbi->exp_timeout = 0;
321         sbi->oz_pgrp = process_group(current);
322         sbi->sb = s;
323         sbi->version = 0;
324         sbi->sub_version = 0;
325         sbi->type = 0;
326         sbi->min_proto = 0;
327         sbi->max_proto = 0;
328         mutex_init(&sbi->wq_mutex);
329         spin_lock_init(&sbi->fs_lock);
330         sbi->queues = NULL;
331         s->s_blocksize = 1024;
332         s->s_blocksize_bits = 10;
333         s->s_magic = AUTOFS_SUPER_MAGIC;
334         s->s_op = &autofs4_sops;
335         s->s_time_gran = 1;
336
337         /*
338          * Get the root inode and dentry, but defer checking for errors.
339          */
340         ino = autofs4_mkroot(sbi);
341         if (!ino)
342                 goto fail_free;
343         root_inode = autofs4_get_inode(s, ino);
344         if (!root_inode)
345                 goto fail_ino;
346
347         root = d_alloc_root(root_inode);
348         if (!root)
349                 goto fail_iput;
350         pipe = NULL;
351
352         root->d_op = &autofs4_sb_dentry_operations;
353         root->d_fsdata = ino;
354
355         /* Can this call block? */
356         if (parse_options(data, &pipefd,
357                           &root_inode->i_uid, &root_inode->i_gid,
358                           &sbi->oz_pgrp, &sbi->type,
359                           &sbi->min_proto, &sbi->max_proto)) {
360                 printk("autofs: called with bogus options\n");
361                 goto fail_dput;
362         }
363
364         root_inode->i_fop = &autofs4_root_operations;
365         root_inode->i_op = sbi->type & AUTOFS_TYPE_DIRECT ?
366                         &autofs4_direct_root_inode_operations :
367                         &autofs4_indirect_root_inode_operations;
368
369         /* Couldn't this be tested earlier? */
370         if (sbi->max_proto < AUTOFS_MIN_PROTO_VERSION ||
371             sbi->min_proto > AUTOFS_MAX_PROTO_VERSION) {
372                 printk("autofs: kernel does not match daemon version "
373                        "daemon (%d, %d) kernel (%d, %d)\n",
374                         sbi->min_proto, sbi->max_proto,
375                         AUTOFS_MIN_PROTO_VERSION, AUTOFS_MAX_PROTO_VERSION);
376                 goto fail_dput;
377         }
378
379         /* Establish highest kernel protocol version */
380         if (sbi->max_proto > AUTOFS_MAX_PROTO_VERSION)
381                 sbi->version = AUTOFS_MAX_PROTO_VERSION;
382         else
383                 sbi->version = sbi->max_proto;
384         sbi->sub_version = AUTOFS_PROTO_SUBVERSION;
385
386         DPRINTK("pipe fd = %d, pgrp = %u", pipefd, sbi->oz_pgrp);
387         pipe = fget(pipefd);
388         
389         if ( !pipe ) {
390                 printk("autofs: could not open pipe file descriptor\n");
391                 goto fail_dput;
392         }
393         if ( !pipe->f_op || !pipe->f_op->write )
394                 goto fail_fput;
395         sbi->pipe = pipe;
396         sbi->pipefd = pipefd;
397
398         /*
399          * Take a reference to the root dentry so we get a chance to
400          * clean up the dentry tree on umount.
401          * See autofs4_force_release.
402          */
403         sbi->root = dget(root);
404
405         /*
406          * Success! Install the root dentry now to indicate completion.
407          */
408         s->s_root = root;
409         return 0;
410         
411         /*
412          * Failure ... clean up.
413          */
414 fail_fput:
415         printk("autofs: pipe file descriptor does not contain proper ops\n");
416         fput(pipe);
417         /* fall through */
418 fail_dput:
419         dput(root);
420         goto fail_free;
421 fail_iput:
422         printk("autofs: get root dentry failed\n");
423         iput(root_inode);
424 fail_ino:
425         kfree(ino);
426 fail_free:
427         kfree(sbi);
428 fail_unlock:
429         return -EINVAL;
430 }
431
432 struct inode *autofs4_get_inode(struct super_block *sb,
433                                 struct autofs_info *inf)
434 {
435         struct inode *inode = new_inode(sb);
436
437         if (inode == NULL)
438                 return NULL;
439
440         inf->inode = inode;
441         inode->i_mode = inf->mode;
442         if (sb->s_root) {
443                 inode->i_uid = sb->s_root->d_inode->i_uid;
444                 inode->i_gid = sb->s_root->d_inode->i_gid;
445         } else {
446                 inode->i_uid = 0;
447                 inode->i_gid = 0;
448         }
449         inode->i_blksize = PAGE_CACHE_SIZE;
450         inode->i_blocks = 0;
451         inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
452
453         if (S_ISDIR(inf->mode)) {
454                 inode->i_nlink = 2;
455                 inode->i_op = &autofs4_dir_inode_operations;
456                 inode->i_fop = &autofs4_dir_operations;
457         } else if (S_ISLNK(inf->mode)) {
458                 inode->i_size = inf->size;
459                 inode->i_op = &autofs4_symlink_inode_operations;
460         }
461
462         return inode;
463 }