Merge branch 'timers-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel...
[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->mode = mode;
57         ino->last_used = jiffies;
58
59         ino->sbi = sbi;
60
61         if (reinit && ino->free)
62                 (ino->free)(ino);
63
64         memset(&ino->u, 0, sizeof(ino->u));
65
66         ino->free = NULL;
67
68         if (S_ISLNK(mode))
69                 ino->free = ino_lnkfree;
70
71         return ino;
72 }
73
74 void autofs4_free_ino(struct autofs_info *ino)
75 {
76         struct autofs_info *p_ino;
77
78         if (ino->dentry) {
79                 ino->dentry->d_fsdata = NULL;
80                 if (ino->dentry->d_inode) {
81                         struct dentry *parent = ino->dentry->d_parent;
82                         if (atomic_dec_and_test(&ino->count)) {
83                                 p_ino = autofs4_dentry_ino(parent);
84                                 if (p_ino && parent != ino->dentry)
85                                         atomic_dec(&p_ino->count);
86                         }
87                         dput(ino->dentry);
88                 }
89                 ino->dentry = NULL;
90         }
91         if (ino->free)
92                 (ino->free)(ino);
93         kfree(ino);
94 }
95
96 /*
97  * Deal with the infamous "Busy inodes after umount ..." message.
98  *
99  * Clean up the dentry tree. This happens with autofs if the user
100  * space program goes away due to a SIGKILL, SIGSEGV etc.
101  */
102 static void autofs4_force_release(struct autofs_sb_info *sbi)
103 {
104         struct dentry *this_parent = sbi->sb->s_root;
105         struct list_head *next;
106
107         if (!sbi->sb->s_root)
108                 return;
109
110         spin_lock(&dcache_lock);
111 repeat:
112         next = this_parent->d_subdirs.next;
113 resume:
114         while (next != &this_parent->d_subdirs) {
115                 struct dentry *dentry = list_entry(next, struct dentry, d_u.d_child);
116
117                 /* Negative dentry - don`t care */
118                 if (!simple_positive(dentry)) {
119                         next = next->next;
120                         continue;
121                 }
122
123                 if (!list_empty(&dentry->d_subdirs)) {
124                         this_parent = dentry;
125                         goto repeat;
126                 }
127
128                 next = next->next;
129                 spin_unlock(&dcache_lock);
130
131                 DPRINTK("dentry %p %.*s",
132                         dentry, (int)dentry->d_name.len, dentry->d_name.name);
133
134                 dput(dentry);
135                 spin_lock(&dcache_lock);
136         }
137
138         if (this_parent != sbi->sb->s_root) {
139                 struct dentry *dentry = this_parent;
140
141                 next = this_parent->d_u.d_child.next;
142                 this_parent = this_parent->d_parent;
143                 spin_unlock(&dcache_lock);
144                 DPRINTK("parent dentry %p %.*s",
145                         dentry, (int)dentry->d_name.len, dentry->d_name.name);
146                 dput(dentry);
147                 spin_lock(&dcache_lock);
148                 goto resume;
149         }
150         spin_unlock(&dcache_lock);
151 }
152
153 void autofs4_kill_sb(struct super_block *sb)
154 {
155         struct autofs_sb_info *sbi = autofs4_sbi(sb);
156
157         /*
158          * In the event of a failure in get_sb_nodev the superblock
159          * info is not present so nothing else has been setup, so
160          * just call kill_anon_super when we are called from
161          * deactivate_super.
162          */
163         if (!sbi)
164                 goto out_kill_sb;
165
166         /* Free wait queues, close pipe */
167         autofs4_catatonic_mode(sbi);
168
169         /* Clean up and release dangling references */
170         autofs4_force_release(sbi);
171
172         sb->s_fs_info = NULL;
173         kfree(sbi);
174
175 out_kill_sb:
176         DPRINTK("shutting down");
177         kill_anon_super(sb);
178 }
179
180 static int autofs4_show_options(struct seq_file *m, struct vfsmount *mnt)
181 {
182         struct autofs_sb_info *sbi = autofs4_sbi(mnt->mnt_sb);
183         struct inode *root_inode = mnt->mnt_sb->s_root->d_inode;
184
185         if (!sbi)
186                 return 0;
187
188         seq_printf(m, ",fd=%d", sbi->pipefd);
189         if (root_inode->i_uid != 0)
190                 seq_printf(m, ",uid=%u", root_inode->i_uid);
191         if (root_inode->i_gid != 0)
192                 seq_printf(m, ",gid=%u", root_inode->i_gid);
193         seq_printf(m, ",pgrp=%d", sbi->oz_pgrp);
194         seq_printf(m, ",timeout=%lu", sbi->exp_timeout/HZ);
195         seq_printf(m, ",minproto=%d", sbi->min_proto);
196         seq_printf(m, ",maxproto=%d", sbi->max_proto);
197
198         if (sbi->type & AUTOFS_TYPE_OFFSET)
199                 seq_printf(m, ",offset");
200         else if (sbi->type & AUTOFS_TYPE_DIRECT)
201                 seq_printf(m, ",direct");
202         else
203                 seq_printf(m, ",indirect");
204
205         return 0;
206 }
207
208 static const struct super_operations autofs4_sops = {
209         .statfs         = simple_statfs,
210         .show_options   = autofs4_show_options,
211 };
212
213 enum {Opt_err, Opt_fd, Opt_uid, Opt_gid, Opt_pgrp, Opt_minproto, Opt_maxproto,
214         Opt_indirect, Opt_direct, Opt_offset};
215
216 static match_table_t tokens = {
217         {Opt_fd, "fd=%u"},
218         {Opt_uid, "uid=%u"},
219         {Opt_gid, "gid=%u"},
220         {Opt_pgrp, "pgrp=%u"},
221         {Opt_minproto, "minproto=%u"},
222         {Opt_maxproto, "maxproto=%u"},
223         {Opt_indirect, "indirect"},
224         {Opt_direct, "direct"},
225         {Opt_offset, "offset"},
226         {Opt_err, NULL}
227 };
228
229 static int parse_options(char *options, int *pipefd, uid_t *uid, gid_t *gid,
230                 pid_t *pgrp, unsigned int *type, int *minproto, int *maxproto)
231 {
232         char *p;
233         substring_t args[MAX_OPT_ARGS];
234         int option;
235
236         *uid = current->uid;
237         *gid = current->gid;
238         *pgrp = task_pgrp_nr(current);
239
240         *minproto = AUTOFS_MIN_PROTO_VERSION;
241         *maxproto = AUTOFS_MAX_PROTO_VERSION;
242
243         *pipefd = -1;
244
245         if (!options)
246                 return 1;
247
248         while ((p = strsep(&options, ",")) != NULL) {
249                 int token;
250                 if (!*p)
251                         continue;
252
253                 token = match_token(p, tokens, args);
254                 switch (token) {
255                 case Opt_fd:
256                         if (match_int(args, pipefd))
257                                 return 1;
258                         break;
259                 case Opt_uid:
260                         if (match_int(args, &option))
261                                 return 1;
262                         *uid = option;
263                         break;
264                 case Opt_gid:
265                         if (match_int(args, &option))
266                                 return 1;
267                         *gid = option;
268                         break;
269                 case Opt_pgrp:
270                         if (match_int(args, &option))
271                                 return 1;
272                         *pgrp = option;
273                         break;
274                 case Opt_minproto:
275                         if (match_int(args, &option))
276                                 return 1;
277                         *minproto = option;
278                         break;
279                 case Opt_maxproto:
280                         if (match_int(args, &option))
281                                 return 1;
282                         *maxproto = option;
283                         break;
284                 case Opt_indirect:
285                         *type = AUTOFS_TYPE_INDIRECT;
286                         break;
287                 case Opt_direct:
288                         *type = AUTOFS_TYPE_DIRECT;
289                         break;
290                 case Opt_offset:
291                         *type = AUTOFS_TYPE_DIRECT | AUTOFS_TYPE_OFFSET;
292                         break;
293                 default:
294                         return 1;
295                 }
296         }
297         return (*pipefd < 0);
298 }
299
300 static struct autofs_info *autofs4_mkroot(struct autofs_sb_info *sbi)
301 {
302         struct autofs_info *ino;
303
304         ino = autofs4_init_ino(NULL, sbi, S_IFDIR | 0755);
305         if (!ino)
306                 return NULL;
307
308         return ino;
309 }
310
311 static struct dentry_operations autofs4_sb_dentry_operations = {
312         .d_release      = autofs4_dentry_release,
313 };
314
315 int autofs4_fill_super(struct super_block *s, void *data, int silent)
316 {
317         struct inode * root_inode;
318         struct dentry * root;
319         struct file * pipe;
320         int pipefd;
321         struct autofs_sb_info *sbi;
322         struct autofs_info *ino;
323
324         sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
325         if (!sbi)
326                 goto fail_unlock;
327         DPRINTK("starting up, sbi = %p",sbi);
328
329         s->s_fs_info = sbi;
330         sbi->magic = AUTOFS_SBI_MAGIC;
331         sbi->pipefd = -1;
332         sbi->pipe = NULL;
333         sbi->catatonic = 1;
334         sbi->exp_timeout = 0;
335         sbi->oz_pgrp = task_pgrp_nr(current);
336         sbi->sb = s;
337         sbi->version = 0;
338         sbi->sub_version = 0;
339         sbi->type = 0;
340         sbi->min_proto = 0;
341         sbi->max_proto = 0;
342         mutex_init(&sbi->wq_mutex);
343         spin_lock_init(&sbi->fs_lock);
344         sbi->queues = NULL;
345         spin_lock_init(&sbi->lookup_lock);
346         INIT_LIST_HEAD(&sbi->active_list);
347         INIT_LIST_HEAD(&sbi->expiring_list);
348         s->s_blocksize = 1024;
349         s->s_blocksize_bits = 10;
350         s->s_magic = AUTOFS_SUPER_MAGIC;
351         s->s_op = &autofs4_sops;
352         s->s_time_gran = 1;
353
354         /*
355          * Get the root inode and dentry, but defer checking for errors.
356          */
357         ino = autofs4_mkroot(sbi);
358         if (!ino)
359                 goto fail_free;
360         root_inode = autofs4_get_inode(s, ino);
361         if (!root_inode)
362                 goto fail_ino;
363
364         root = d_alloc_root(root_inode);
365         if (!root)
366                 goto fail_iput;
367         pipe = NULL;
368
369         root->d_op = &autofs4_sb_dentry_operations;
370         root->d_fsdata = ino;
371
372         /* Can this call block? */
373         if (parse_options(data, &pipefd, &root_inode->i_uid, &root_inode->i_gid,
374                                 &sbi->oz_pgrp, &sbi->type, &sbi->min_proto,
375                                 &sbi->max_proto)) {
376                 printk("autofs: called with bogus options\n");
377                 goto fail_dput;
378         }
379
380         root_inode->i_fop = &autofs4_root_operations;
381         root_inode->i_op = sbi->type & AUTOFS_TYPE_DIRECT ?
382                         &autofs4_direct_root_inode_operations :
383                         &autofs4_indirect_root_inode_operations;
384
385         /* Couldn't this be tested earlier? */
386         if (sbi->max_proto < AUTOFS_MIN_PROTO_VERSION ||
387             sbi->min_proto > AUTOFS_MAX_PROTO_VERSION) {
388                 printk("autofs: kernel does not match daemon version "
389                        "daemon (%d, %d) kernel (%d, %d)\n",
390                         sbi->min_proto, sbi->max_proto,
391                         AUTOFS_MIN_PROTO_VERSION, AUTOFS_MAX_PROTO_VERSION);
392                 goto fail_dput;
393         }
394
395         /* Establish highest kernel protocol version */
396         if (sbi->max_proto > AUTOFS_MAX_PROTO_VERSION)
397                 sbi->version = AUTOFS_MAX_PROTO_VERSION;
398         else
399                 sbi->version = sbi->max_proto;
400         sbi->sub_version = AUTOFS_PROTO_SUBVERSION;
401
402         DPRINTK("pipe fd = %d, pgrp = %u", pipefd, sbi->oz_pgrp);
403         pipe = fget(pipefd);
404         
405         if (!pipe) {
406                 printk("autofs: could not open pipe file descriptor\n");
407                 goto fail_dput;
408         }
409         if (!pipe->f_op || !pipe->f_op->write)
410                 goto fail_fput;
411         sbi->pipe = pipe;
412         sbi->pipefd = pipefd;
413         sbi->catatonic = 0;
414
415         /*
416          * Success! Install the root dentry now to indicate completion.
417          */
418         s->s_root = root;
419         return 0;
420         
421         /*
422          * Failure ... clean up.
423          */
424 fail_fput:
425         printk("autofs: pipe file descriptor does not contain proper ops\n");
426         fput(pipe);
427         /* fall through */
428 fail_dput:
429         dput(root);
430         goto fail_free;
431 fail_iput:
432         printk("autofs: get root dentry failed\n");
433         iput(root_inode);
434 fail_ino:
435         kfree(ino);
436 fail_free:
437         kfree(sbi);
438         s->s_fs_info = NULL;
439 fail_unlock:
440         return -EINVAL;
441 }
442
443 struct inode *autofs4_get_inode(struct super_block *sb,
444                                 struct autofs_info *inf)
445 {
446         struct inode *inode = new_inode(sb);
447
448         if (inode == NULL)
449                 return NULL;
450
451         inf->inode = inode;
452         inode->i_mode = inf->mode;
453         if (sb->s_root) {
454                 inode->i_uid = sb->s_root->d_inode->i_uid;
455                 inode->i_gid = sb->s_root->d_inode->i_gid;
456         } else {
457                 inode->i_uid = 0;
458                 inode->i_gid = 0;
459         }
460         inode->i_blocks = 0;
461         inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
462
463         if (S_ISDIR(inf->mode)) {
464                 inode->i_nlink = 2;
465                 inode->i_op = &autofs4_dir_inode_operations;
466                 inode->i_fop = &autofs4_dir_operations;
467         } else if (S_ISLNK(inf->mode)) {
468                 inode->i_size = inf->size;
469                 inode->i_op = &autofs4_symlink_inode_operations;
470         }
471
472         return inode;
473 }