autofs4: don't make expiring dentry negative
[linux-2.6.git] / 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         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         INIT_LIST_HEAD(&ino->expiring);
51
52         ino->last_used = jiffies;
53         atomic_set(&ino->count, 0);
54
55         ino->sbi = sbi;
56
57         if (reinit && ino->free)
58                 (ino->free)(ino);
59
60         memset(&ino->u, 0, sizeof(ino->u));
61
62         ino->free = NULL;
63
64         if (S_ISLNK(mode))
65                 ino->free = ino_lnkfree;
66
67         return ino;
68 }
69
70 void autofs4_free_ino(struct autofs_info *ino)
71 {
72         struct autofs_info *p_ino;
73
74         if (ino->dentry) {
75                 ino->dentry->d_fsdata = NULL;
76                 if (ino->dentry->d_inode) {
77                         struct dentry *parent = ino->dentry->d_parent;
78                         if (atomic_dec_and_test(&ino->count)) {
79                                 p_ino = autofs4_dentry_ino(parent);
80                                 if (p_ino && parent != ino->dentry)
81                                         atomic_dec(&p_ino->count);
82                         }
83                         dput(ino->dentry);
84                 }
85                 ino->dentry = NULL;
86         }
87         if (ino->free)
88                 (ino->free)(ino);
89         kfree(ino);
90 }
91
92 /*
93  * Deal with the infamous "Busy inodes after umount ..." message.
94  *
95  * Clean up the dentry tree. This happens with autofs if the user
96  * space program goes away due to a SIGKILL, SIGSEGV etc.
97  */
98 static void autofs4_force_release(struct autofs_sb_info *sbi)
99 {
100         struct dentry *this_parent = sbi->sb->s_root;
101         struct list_head *next;
102
103         if (!sbi->sb->s_root)
104                 return;
105
106         spin_lock(&dcache_lock);
107 repeat:
108         next = this_parent->d_subdirs.next;
109 resume:
110         while (next != &this_parent->d_subdirs) {
111                 struct dentry *dentry = list_entry(next, struct dentry, d_u.d_child);
112
113                 /* Negative dentry - don`t care */
114                 if (!simple_positive(dentry)) {
115                         next = next->next;
116                         continue;
117                 }
118
119                 if (!list_empty(&dentry->d_subdirs)) {
120                         this_parent = dentry;
121                         goto repeat;
122                 }
123
124                 next = next->next;
125                 spin_unlock(&dcache_lock);
126
127                 DPRINTK("dentry %p %.*s",
128                         dentry, (int)dentry->d_name.len, dentry->d_name.name);
129
130                 dput(dentry);
131                 spin_lock(&dcache_lock);
132         }
133
134         if (this_parent != sbi->sb->s_root) {
135                 struct dentry *dentry = this_parent;
136
137                 next = this_parent->d_u.d_child.next;
138                 this_parent = this_parent->d_parent;
139                 spin_unlock(&dcache_lock);
140                 DPRINTK("parent dentry %p %.*s",
141                         dentry, (int)dentry->d_name.len, dentry->d_name.name);
142                 dput(dentry);
143                 spin_lock(&dcache_lock);
144                 goto resume;
145         }
146         spin_unlock(&dcache_lock);
147 }
148
149 void autofs4_kill_sb(struct super_block *sb)
150 {
151         struct autofs_sb_info *sbi = autofs4_sbi(sb);
152
153         /*
154          * In the event of a failure in get_sb_nodev the superblock
155          * info is not present so nothing else has been setup, so
156          * just call kill_anon_super when we are called from
157          * deactivate_super.
158          */
159         if (!sbi)
160                 goto out_kill_sb;
161
162         if (!sbi->catatonic)
163                 autofs4_catatonic_mode(sbi); /* Free wait queues, close pipe */
164
165         /* Clean up and release dangling references */
166         autofs4_force_release(sbi);
167
168         sb->s_fs_info = NULL;
169         kfree(sbi);
170
171 out_kill_sb:
172         DPRINTK("shutting down");
173         kill_anon_super(sb);
174 }
175
176 static int autofs4_show_options(struct seq_file *m, struct vfsmount *mnt)
177 {
178         struct autofs_sb_info *sbi = autofs4_sbi(mnt->mnt_sb);
179         struct inode *root_inode = mnt->mnt_sb->s_root->d_inode;
180
181         if (!sbi)
182                 return 0;
183
184         seq_printf(m, ",fd=%d", sbi->pipefd);
185         if (root_inode->i_uid != 0)
186                 seq_printf(m, ",uid=%u", root_inode->i_uid);
187         if (root_inode->i_gid != 0)
188                 seq_printf(m, ",gid=%u", root_inode->i_gid);
189         seq_printf(m, ",pgrp=%d", sbi->oz_pgrp);
190         seq_printf(m, ",timeout=%lu", sbi->exp_timeout/HZ);
191         seq_printf(m, ",minproto=%d", sbi->min_proto);
192         seq_printf(m, ",maxproto=%d", sbi->max_proto);
193
194         if (sbi->type & AUTOFS_TYPE_OFFSET)
195                 seq_printf(m, ",offset");
196         else if (sbi->type & AUTOFS_TYPE_DIRECT)
197                 seq_printf(m, ",direct");
198         else
199                 seq_printf(m, ",indirect");
200
201         return 0;
202 }
203
204 static const struct super_operations autofs4_sops = {
205         .statfs         = simple_statfs,
206         .show_options   = autofs4_show_options,
207 };
208
209 enum {Opt_err, Opt_fd, Opt_uid, Opt_gid, Opt_pgrp, Opt_minproto, Opt_maxproto,
210         Opt_indirect, Opt_direct, Opt_offset};
211
212 static match_table_t tokens = {
213         {Opt_fd, "fd=%u"},
214         {Opt_uid, "uid=%u"},
215         {Opt_gid, "gid=%u"},
216         {Opt_pgrp, "pgrp=%u"},
217         {Opt_minproto, "minproto=%u"},
218         {Opt_maxproto, "maxproto=%u"},
219         {Opt_indirect, "indirect"},
220         {Opt_direct, "direct"},
221         {Opt_offset, "offset"},
222         {Opt_err, NULL}
223 };
224
225 static int parse_options(char *options, int *pipefd, uid_t *uid, gid_t *gid,
226                 pid_t *pgrp, unsigned int *type, int *minproto, int *maxproto)
227 {
228         char *p;
229         substring_t args[MAX_OPT_ARGS];
230         int option;
231
232         *uid = current->uid;
233         *gid = current->gid;
234         *pgrp = task_pgrp_nr(current);
235
236         *minproto = AUTOFS_MIN_PROTO_VERSION;
237         *maxproto = AUTOFS_MAX_PROTO_VERSION;
238
239         *pipefd = -1;
240
241         if (!options)
242                 return 1;
243
244         while ((p = strsep(&options, ",")) != NULL) {
245                 int token;
246                 if (!*p)
247                         continue;
248
249                 token = match_token(p, tokens, args);
250                 switch (token) {
251                 case Opt_fd:
252                         if (match_int(args, pipefd))
253                                 return 1;
254                         break;
255                 case Opt_uid:
256                         if (match_int(args, &option))
257                                 return 1;
258                         *uid = option;
259                         break;
260                 case Opt_gid:
261                         if (match_int(args, &option))
262                                 return 1;
263                         *gid = option;
264                         break;
265                 case Opt_pgrp:
266                         if (match_int(args, &option))
267                                 return 1;
268                         *pgrp = option;
269                         break;
270                 case Opt_minproto:
271                         if (match_int(args, &option))
272                                 return 1;
273                         *minproto = option;
274                         break;
275                 case Opt_maxproto:
276                         if (match_int(args, &option))
277                                 return 1;
278                         *maxproto = option;
279                         break;
280                 case Opt_indirect:
281                         *type = AUTOFS_TYPE_INDIRECT;
282                         break;
283                 case Opt_direct:
284                         *type = AUTOFS_TYPE_DIRECT;
285                         break;
286                 case Opt_offset:
287                         *type = AUTOFS_TYPE_DIRECT | AUTOFS_TYPE_OFFSET;
288                         break;
289                 default:
290                         return 1;
291                 }
292         }
293         return (*pipefd < 0);
294 }
295
296 static struct autofs_info *autofs4_mkroot(struct autofs_sb_info *sbi)
297 {
298         struct autofs_info *ino;
299
300         ino = autofs4_init_ino(NULL, sbi, S_IFDIR | 0755);
301         if (!ino)
302                 return NULL;
303
304         return ino;
305 }
306
307 static struct dentry_operations autofs4_sb_dentry_operations = {
308         .d_release      = autofs4_dentry_release,
309 };
310
311 int autofs4_fill_super(struct super_block *s, void *data, int silent)
312 {
313         struct inode * root_inode;
314         struct dentry * root;
315         struct file * pipe;
316         int pipefd;
317         struct autofs_sb_info *sbi;
318         struct autofs_info *ino;
319
320         sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
321         if (!sbi)
322                 goto fail_unlock;
323         DPRINTK("starting up, sbi = %p",sbi);
324
325         s->s_fs_info = sbi;
326         sbi->magic = AUTOFS_SBI_MAGIC;
327         sbi->pipefd = -1;
328         sbi->pipe = NULL;
329         sbi->catatonic = 1;
330         sbi->exp_timeout = 0;
331         sbi->oz_pgrp = task_pgrp_nr(current);
332         sbi->sb = s;
333         sbi->version = 0;
334         sbi->sub_version = 0;
335         sbi->type = 0;
336         sbi->min_proto = 0;
337         sbi->max_proto = 0;
338         mutex_init(&sbi->wq_mutex);
339         spin_lock_init(&sbi->fs_lock);
340         sbi->queues = NULL;
341         spin_lock_init(&sbi->lookup_lock);
342         INIT_LIST_HEAD(&sbi->expiring_list);
343         s->s_blocksize = 1024;
344         s->s_blocksize_bits = 10;
345         s->s_magic = AUTOFS_SUPER_MAGIC;
346         s->s_op = &autofs4_sops;
347         s->s_time_gran = 1;
348
349         /*
350          * Get the root inode and dentry, but defer checking for errors.
351          */
352         ino = autofs4_mkroot(sbi);
353         if (!ino)
354                 goto fail_free;
355         root_inode = autofs4_get_inode(s, ino);
356         if (!root_inode)
357                 goto fail_ino;
358
359         root = d_alloc_root(root_inode);
360         if (!root)
361                 goto fail_iput;
362         pipe = NULL;
363
364         root->d_op = &autofs4_sb_dentry_operations;
365         root->d_fsdata = ino;
366
367         /* Can this call block? */
368         if (parse_options(data, &pipefd, &root_inode->i_uid, &root_inode->i_gid,
369                                 &sbi->oz_pgrp, &sbi->type, &sbi->min_proto,
370                                 &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 }