summaryrefslogtreecommitdiffstats
path: root/fs/autofs4/inode.c
blob: 818b37be5153f3d7508ac00c215c2f523f01999f (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
/* -*- c -*- --------------------------------------------------------------- *
 *
 * linux/fs/autofs/inode.c
 *
 *  Copyright 1997-1998 Transmeta Corporation -- All Rights Reserved
 *
 * This file is part of the Linux kernel and is made available under
 * the terms of the GNU General Public License, version 2, or at your
 * option, any later version, incorporated herein by reference.
 *
 * ------------------------------------------------------------------------- */

#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/file.h>
#include <linux/pagemap.h>
#include <linux/parser.h>
#include <linux/bitops.h>
#include <linux/smp_lock.h>
#include "autofs_i.h"
#include <linux/module.h>

static void ino_lnkfree(struct autofs_info *ino)
{
	kfree(ino->u.symlink);
	ino->u.symlink = NULL;
}

struct autofs_info *autofs4_init_ino(struct autofs_info *ino,
				     struct autofs_sb_info *sbi, mode_t mode)
{
	int reinit = 1;

	if (ino == NULL) {
		reinit = 0;
		ino = kmalloc(sizeof(*ino), GFP_KERNEL);
	}

	if (ino == NULL)
		return NULL;

	ino->flags = 0;
	ino->mode = mode;
	ino->inode = NULL;
	ino->dentry = NULL;
	ino->size = 0;

	ino->last_used = jiffies;

	ino->sbi = sbi;

	if (reinit && ino->free)
		(ino->free)(ino);

	memset(&ino->u, 0, sizeof(ino->u));

	ino->free = NULL;

	if (S_ISLNK(mode))
		ino->free = ino_lnkfree;

	return ino;
}

void autofs4_free_ino(struct autofs_info *ino)
{
	if (ino->dentry) {
		ino->dentry->d_fsdata = NULL;
		if (ino->dentry->d_inode)
			dput(ino->dentry);
		ino->dentry = NULL;
	}
	if (ino->free)
		(ino->free)(ino);
	kfree(ino);
}

/*
 * Deal with the infamous "Busy inodes after umount ..." message.
 *
 * Clean up the dentry tree. This happens with autofs if the user
 * space program goes away due to a SIGKILL, SIGSEGV etc.
 */
static void autofs4_force_release(struct autofs_sb_info *sbi)
{
	struct dentry *this_parent = sbi->root;
	struct list_head *next;

	spin_lock(&dcache_lock);
repeat:
	next = this_parent->d_subdirs.next;
resume:
	while (next != &this_parent->d_subdirs) {
		struct dentry *dentry = list_entry(next, struct dentry, d_child);

		/* Negative dentry - don`t care */
		if (!simple_positive(dentry)) {
			next = next->next;
			continue;
		}

		if (!list_empty(&dentry->d_subdirs)) {
			this_parent = dentry;
			goto repeat;
		}

		next = next->next;
		spin_unlock(&dcache_lock);

		DPRINTK("dentry %p %.*s",
			dentry, (int)dentry->d_name.len, dentry->d_name.name);

		dput(dentry);
		spin_lock(&dcache_lock);
	}

	if (this_parent != sbi->root) {
		struct dentry *dentry = this_parent;

		next = this_parent->d_child.next;
		this_parent = this_parent->d_parent;
		spin_unlock(&dcache_lock);
		DPRINTK("parent dentry %p %.*s",
			dentry, (int)dentry->d_name.len, dentry->d_name.name);
		dput(dentry);
		spin_lock(&dcache_lock);
		goto resume;
	}
	spin_unlock(&dcache_lock);

	dput(sbi->root);
	sbi->root = NULL;
	shrink_dcache_sb(sbi->sb);

	return;
}

static void autofs4_put_super(struct super_block *sb)
{
	struct autofs_sb_info *sbi = autofs4_sbi(sb);

	sb->s_fs_info = NULL;

	if ( !sbi->catatonic )
		autofs4_catatonic_mode(sbi); /* Free wait queues, close pipe */

	/* Clean up and release dangling references */
	if (sbi)
		autofs4_force_release(sbi);

	kfree(sbi);

	DPRINTK("shutting down");
}

static struct super_operations autofs4_sops = {
	.put_super	= autofs4_put_super,
	.statfs		= simple_statfs,
};

enum {Opt_err, Opt_fd, Opt_uid, Opt_gid, Opt_pgrp, Opt_minproto, Opt_maxproto};

static match_table_t tokens = {
	{Opt_fd, "fd=%u"},
	{Opt_uid, "uid=%u"},
	{Opt_gid, "gid=%u"},
	{Opt_pgrp, "pgrp=%u"},
	{Opt_minproto, "minproto=%u"},
	{Opt_maxproto, "maxproto=%u"},
	{Opt_err, NULL}
};

static int parse_options(char *options, int *pipefd, uid_t *uid, gid_t *gid,
			 pid_t *pgrp, int *minproto, int *maxproto)
{
	char *p;
	substring_t args[MAX_OPT_ARGS];
	int option;

	*uid = current->uid;
	*gid = current->gid;
	*pgrp = process_group(current);

	*minproto = AUTOFS_MIN_PROTO_VERSION;
	*maxproto = AUTOFS_MAX_PROTO_VERSION;

	*pipefd = -1;

	if (!options)
		return 1;

	while ((p = strsep(&options, ",")) != NULL) {
		int token;
		if (!*p)
			continue;

		token = match_token(p, tokens, args);
		switch (token) {
		case Opt_fd:
			if (match_int(args, pipefd))
				return 1;
			break;
		case Opt_uid:
			if (match_int(args, &option))
				return 1;
			*uid = option;
			break;
		case Opt_gid:
			if (match_int(args, &option))
				return 1;
			*gid = option;
			break;
		case Opt_pgrp:
			if (match_int(args, &option))
				return 1;
			*pgrp = option;
			break;
		case Opt_minproto:
			if (match_int(args, &option))
				return 1;
			*minproto = option;
			break;
		case Opt_maxproto:
			if (match_int(args, &option))
				return 1;
			*maxproto = option;
			break;
		default:
			return 1;
		}
	}
	return (*pipefd < 0);
}

static struct autofs_info *autofs4_mkroot(struct autofs_sb_info *sbi)
{
	struct autofs_info *ino;

	ino = autofs4_init_ino(NULL, sbi, S_IFDIR | 0755);
	if (!ino)
		return NULL;

	return ino;
}

int autofs4_fill_super(struct super_block *s, void *data, int silent)
{
	struct inode * root_inode;
	struct dentry * root;
	struct file * pipe;
	int pipefd;
	struct autofs_sb_info *sbi;
	struct autofs_info *ino;
	int minproto, maxproto;

	sbi = (struct autofs_sb_info *) kmalloc(sizeof(*sbi), GFP_KERNEL);
	if ( !sbi )
		goto fail_unlock;
	DPRINTK("starting up, sbi = %p",sbi);

	memset(sbi, 0, sizeof(*sbi));

	s->s_fs_info = sbi;
	sbi->magic = AUTOFS_SBI_MAGIC;
	sbi->root = NULL;
	sbi->catatonic = 0;
	sbi->exp_timeout = 0;
	sbi->oz_pgrp = process_group(current);
	sbi->sb = s;
	sbi->version = 0;
	sbi->sub_version = 0;
	init_MUTEX(&sbi->wq_sem);
	spin_lock_init(&sbi->fs_lock);
	sbi->queues = NULL;
	s->s_blocksize = 1024;
	s->s_blocksize_bits = 10;
	s->s_magic = AUTOFS_SUPER_MAGIC;
	s->s_op = &autofs4_sops;
	s->s_time_gran = 1;

	/*
	 * Get the root inode and dentry, but defer checking for errors.
	 */
	ino = autofs4_mkroot(sbi);
	if (!ino)
		goto fail_free;
	root_inode = autofs4_get_inode(s, ino);
	kfree(ino);
	if (!root_inode)
		goto fail_free;

	root_inode->i_op = &autofs4_root_inode_operations;
	root_inode->i_fop = &autofs4_root_operations;
	root = d_alloc_root(root_inode);
	pipe = NULL;

	if (!root)
		goto fail_iput;

	/* Can this call block? */
	if (parse_options(data, &pipefd,
			  &root_inode->i_uid, &root_inode->i_gid,
			  &sbi->oz_pgrp,
			  &minproto, &maxproto)) {
		printk("autofs: called with bogus options\n");
		goto fail_dput;
	}

	/* Couldn't this be tested earlier? */
	if (maxproto < AUTOFS_MIN_PROTO_VERSION ||
	    minproto > AUTOFS_MAX_PROTO_VERSION) {
		printk("autofs: kernel does not match daemon version "
		       "daemon (%d, %d) kernel (%d, %d)\n",
			minproto, maxproto,
			AUTOFS_MIN_PROTO_VERSION, AUTOFS_MAX_PROTO_VERSION);
		goto fail_dput;
	}

	sbi->version = maxproto > AUTOFS_MAX_PROTO_VERSION ? AUTOFS_MAX_PROTO_VERSION : maxproto;
	sbi->sub_version = AUTOFS_PROTO_SUBVERSION;

	DPRINTK("pipe fd = %d, pgrp = %u", pipefd, sbi->oz_pgrp);
	pipe = fget(pipefd);
	
	if ( !pipe ) {
		printk("autofs: could not open pipe file descriptor\n");
		goto fail_dput;
	}
	if ( !pipe->f_op || !pipe->f_op->write )
		goto fail_fput;
	sbi->pipe = pipe;

	/*
	 * Take a reference to the root dentry so we get a chance to
	 * clean up the dentry tree on umount.
	 * See autofs4_force_release.
	 */
	sbi->root = dget(root);

	/*
	 * Success! Install the root dentry now to indicate completion.
	 */
	s->s_root = root;
	return 0;
	
	/*
	 * Failure ... clean up.
	 */
fail_fput:
	printk("autofs: pipe file descriptor does not contain proper ops\n");
	fput(pipe);
	/* fall through */
fail_dput:
	dput(root);
	goto fail_free;
fail_iput:
	printk("autofs: get root dentry failed\n");
	iput(root_inode);
fail_free:
	kfree(sbi);
fail_unlock:
	return -EINVAL;
}

struct inode *autofs4_get_inode(struct super_block *sb,
				struct autofs_info *inf)
{
	struct inode *inode = new_inode(sb);

	if (inode == NULL)
		return NULL;

	inf->inode = inode;
	inode->i_mode = inf->mode;
	if (sb->s_root) {
		inode->i_uid = sb->s_root->d_inode->i_uid;
		inode->i_gid = sb->s_root->d_inode->i_gid;
	} else {
		inode->i_uid = 0;
		inode->i_gid = 0;
	}
	inode->i_blksize = PAGE_CACHE_SIZE;
	inode->i_blocks = 0;
	inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;

	if (S_ISDIR(inf->mode)) {
		inode->i_nlink = 2;
		inode->i_op = &autofs4_dir_inode_operations;
		inode->i_fop = &autofs4_dir_operations;
	} else if (S_ISLNK(inf->mode)) {
		inode->i_size = inf->size;
		inode->i_op = &autofs4_symlink_inode_operations;
	}

	return inode;
}
OpenPOWER on IntegriCloud