Merge tag 'writeback' of git://git.kernel.org/pub/scm/linux/kernel/git/wfg/linux
[linux-3.10.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 struct autofs_info *autofs4_new_ino(struct autofs_sb_info *sbi)
26 {
27         struct autofs_info *ino = kzalloc(sizeof(*ino), GFP_KERNEL);
28         if (ino) {
29                 INIT_LIST_HEAD(&ino->active);
30                 INIT_LIST_HEAD(&ino->expiring);
31                 ino->last_used = jiffies;
32                 ino->sbi = sbi;
33         }
34         return ino;
35 }
36
37 void autofs4_clean_ino(struct autofs_info *ino)
38 {
39         ino->uid = 0;
40         ino->gid = 0;
41         ino->last_used = jiffies;
42 }
43
44 void autofs4_free_ino(struct autofs_info *ino)
45 {
46         kfree(ino);
47 }
48
49 void autofs4_kill_sb(struct super_block *sb)
50 {
51         struct autofs_sb_info *sbi = autofs4_sbi(sb);
52
53         /*
54          * In the event of a failure in get_sb_nodev the superblock
55          * info is not present so nothing else has been setup, so
56          * just call kill_anon_super when we are called from
57          * deactivate_super.
58          */
59         if (!sbi)
60                 goto out_kill_sb;
61
62         /* Free wait queues, close pipe */
63         autofs4_catatonic_mode(sbi);
64
65         sb->s_fs_info = NULL;
66         kfree(sbi);
67
68 out_kill_sb:
69         DPRINTK("shutting down");
70         kill_litter_super(sb);
71 }
72
73 static int autofs4_show_options(struct seq_file *m, struct dentry *root)
74 {
75         struct autofs_sb_info *sbi = autofs4_sbi(root->d_sb);
76         struct inode *root_inode = root->d_sb->s_root->d_inode;
77
78         if (!sbi)
79                 return 0;
80
81         seq_printf(m, ",fd=%d", sbi->pipefd);
82         if (root_inode->i_uid != 0)
83                 seq_printf(m, ",uid=%u", root_inode->i_uid);
84         if (root_inode->i_gid != 0)
85                 seq_printf(m, ",gid=%u", root_inode->i_gid);
86         seq_printf(m, ",pgrp=%d", sbi->oz_pgrp);
87         seq_printf(m, ",timeout=%lu", sbi->exp_timeout/HZ);
88         seq_printf(m, ",minproto=%d", sbi->min_proto);
89         seq_printf(m, ",maxproto=%d", sbi->max_proto);
90
91         if (autofs_type_offset(sbi->type))
92                 seq_printf(m, ",offset");
93         else if (autofs_type_direct(sbi->type))
94                 seq_printf(m, ",direct");
95         else
96                 seq_printf(m, ",indirect");
97
98         return 0;
99 }
100
101 static void autofs4_evict_inode(struct inode *inode)
102 {
103         clear_inode(inode);
104         kfree(inode->i_private);
105 }
106
107 static const struct super_operations autofs4_sops = {
108         .statfs         = simple_statfs,
109         .show_options   = autofs4_show_options,
110         .evict_inode    = autofs4_evict_inode,
111 };
112
113 enum {Opt_err, Opt_fd, Opt_uid, Opt_gid, Opt_pgrp, Opt_minproto, Opt_maxproto,
114         Opt_indirect, Opt_direct, Opt_offset};
115
116 static const match_table_t tokens = {
117         {Opt_fd, "fd=%u"},
118         {Opt_uid, "uid=%u"},
119         {Opt_gid, "gid=%u"},
120         {Opt_pgrp, "pgrp=%u"},
121         {Opt_minproto, "minproto=%u"},
122         {Opt_maxproto, "maxproto=%u"},
123         {Opt_indirect, "indirect"},
124         {Opt_direct, "direct"},
125         {Opt_offset, "offset"},
126         {Opt_err, NULL}
127 };
128
129 static int parse_options(char *options, int *pipefd, uid_t *uid, gid_t *gid,
130                 pid_t *pgrp, unsigned int *type, int *minproto, int *maxproto)
131 {
132         char *p;
133         substring_t args[MAX_OPT_ARGS];
134         int option;
135
136         *uid = current_uid();
137         *gid = current_gid();
138         *pgrp = task_pgrp_nr(current);
139
140         *minproto = AUTOFS_MIN_PROTO_VERSION;
141         *maxproto = AUTOFS_MAX_PROTO_VERSION;
142
143         *pipefd = -1;
144
145         if (!options)
146                 return 1;
147
148         while ((p = strsep(&options, ",")) != NULL) {
149                 int token;
150                 if (!*p)
151                         continue;
152
153                 token = match_token(p, tokens, args);
154                 switch (token) {
155                 case Opt_fd:
156                         if (match_int(args, pipefd))
157                                 return 1;
158                         break;
159                 case Opt_uid:
160                         if (match_int(args, &option))
161                                 return 1;
162                         *uid = option;
163                         break;
164                 case Opt_gid:
165                         if (match_int(args, &option))
166                                 return 1;
167                         *gid = option;
168                         break;
169                 case Opt_pgrp:
170                         if (match_int(args, &option))
171                                 return 1;
172                         *pgrp = option;
173                         break;
174                 case Opt_minproto:
175                         if (match_int(args, &option))
176                                 return 1;
177                         *minproto = option;
178                         break;
179                 case Opt_maxproto:
180                         if (match_int(args, &option))
181                                 return 1;
182                         *maxproto = option;
183                         break;
184                 case Opt_indirect:
185                         set_autofs_type_indirect(type);
186                         break;
187                 case Opt_direct:
188                         set_autofs_type_direct(type);
189                         break;
190                 case Opt_offset:
191                         set_autofs_type_offset(type);
192                         break;
193                 default:
194                         return 1;
195                 }
196         }
197         return (*pipefd < 0);
198 }
199
200 int autofs4_fill_super(struct super_block *s, void *data, int silent)
201 {
202         struct inode * root_inode;
203         struct dentry * root;
204         struct file * pipe;
205         int pipefd;
206         struct autofs_sb_info *sbi;
207         struct autofs_info *ino;
208
209         sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
210         if (!sbi)
211                 goto fail_unlock;
212         DPRINTK("starting up, sbi = %p",sbi);
213
214         s->s_fs_info = sbi;
215         sbi->magic = AUTOFS_SBI_MAGIC;
216         sbi->pipefd = -1;
217         sbi->pipe = NULL;
218         sbi->catatonic = 1;
219         sbi->exp_timeout = 0;
220         sbi->oz_pgrp = task_pgrp_nr(current);
221         sbi->sb = s;
222         sbi->version = 0;
223         sbi->sub_version = 0;
224         set_autofs_type_indirect(&sbi->type);
225         sbi->min_proto = 0;
226         sbi->max_proto = 0;
227         mutex_init(&sbi->wq_mutex);
228         mutex_init(&sbi->pipe_mutex);
229         spin_lock_init(&sbi->fs_lock);
230         sbi->queues = NULL;
231         spin_lock_init(&sbi->lookup_lock);
232         INIT_LIST_HEAD(&sbi->active_list);
233         INIT_LIST_HEAD(&sbi->expiring_list);
234         s->s_blocksize = 1024;
235         s->s_blocksize_bits = 10;
236         s->s_magic = AUTOFS_SUPER_MAGIC;
237         s->s_op = &autofs4_sops;
238         s->s_d_op = &autofs4_dentry_operations;
239         s->s_time_gran = 1;
240
241         /*
242          * Get the root inode and dentry, but defer checking for errors.
243          */
244         ino = autofs4_new_ino(sbi);
245         if (!ino)
246                 goto fail_free;
247         root_inode = autofs4_get_inode(s, S_IFDIR | 0755);
248         root = d_make_root(root_inode);
249         if (!root)
250                 goto fail_ino;
251         pipe = NULL;
252
253         root->d_fsdata = ino;
254
255         /* Can this call block? */
256         if (parse_options(data, &pipefd, &root_inode->i_uid, &root_inode->i_gid,
257                                 &sbi->oz_pgrp, &sbi->type, &sbi->min_proto,
258                                 &sbi->max_proto)) {
259                 printk("autofs: called with bogus options\n");
260                 goto fail_dput;
261         }
262
263         if (autofs_type_trigger(sbi->type))
264                 __managed_dentry_set_managed(root);
265
266         root_inode->i_fop = &autofs4_root_operations;
267         root_inode->i_op = &autofs4_dir_inode_operations;
268
269         /* Couldn't this be tested earlier? */
270         if (sbi->max_proto < AUTOFS_MIN_PROTO_VERSION ||
271             sbi->min_proto > AUTOFS_MAX_PROTO_VERSION) {
272                 printk("autofs: kernel does not match daemon version "
273                        "daemon (%d, %d) kernel (%d, %d)\n",
274                         sbi->min_proto, sbi->max_proto,
275                         AUTOFS_MIN_PROTO_VERSION, AUTOFS_MAX_PROTO_VERSION);
276                 goto fail_dput;
277         }
278
279         /* Establish highest kernel protocol version */
280         if (sbi->max_proto > AUTOFS_MAX_PROTO_VERSION)
281                 sbi->version = AUTOFS_MAX_PROTO_VERSION;
282         else
283                 sbi->version = sbi->max_proto;
284         sbi->sub_version = AUTOFS_PROTO_SUBVERSION;
285
286         DPRINTK("pipe fd = %d, pgrp = %u", pipefd, sbi->oz_pgrp);
287         pipe = fget(pipefd);
288         
289         if (!pipe) {
290                 printk("autofs: could not open pipe file descriptor\n");
291                 goto fail_dput;
292         }
293         if (autofs_prepare_pipe(pipe) < 0)
294                 goto fail_fput;
295         sbi->pipe = pipe;
296         sbi->pipefd = pipefd;
297         sbi->catatonic = 0;
298
299         /*
300          * Success! Install the root dentry now to indicate completion.
301          */
302         s->s_root = root;
303         return 0;
304         
305         /*
306          * Failure ... clean up.
307          */
308 fail_fput:
309         printk("autofs: pipe file descriptor does not contain proper ops\n");
310         fput(pipe);
311         /* fall through */
312 fail_dput:
313         dput(root);
314         goto fail_free;
315 fail_ino:
316         kfree(ino);
317 fail_free:
318         kfree(sbi);
319         s->s_fs_info = NULL;
320 fail_unlock:
321         return -EINVAL;
322 }
323
324 struct inode *autofs4_get_inode(struct super_block *sb, umode_t mode)
325 {
326         struct inode *inode = new_inode(sb);
327
328         if (inode == NULL)
329                 return NULL;
330
331         inode->i_mode = mode;
332         if (sb->s_root) {
333                 inode->i_uid = sb->s_root->d_inode->i_uid;
334                 inode->i_gid = sb->s_root->d_inode->i_gid;
335         }
336         inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
337         inode->i_ino = get_next_ino();
338
339         if (S_ISDIR(mode)) {
340                 set_nlink(inode, 2);
341                 inode->i_op = &autofs4_dir_inode_operations;
342                 inode->i_fop = &autofs4_dir_operations;
343         } else if (S_ISLNK(mode)) {
344                 inode->i_op = &autofs4_symlink_inode_operations;
345         }
346
347         return inode;
348 }