aboutsummaryrefslogtreecommitdiff
path: root/arch/s390/hypfs/inode.c
blob: 06ea69bd387a00c7b31a4894d356383d9322426f (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
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
/*
 *    Hypervisor filesystem for Linux on s390.
 *
 *    Copyright IBM Corp. 2006, 2008
 *    Author(s): Michael Holzheu <holzheu@de.ibm.com>
 */

#define KMSG_COMPONENT "hypfs"
#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt

#include <linux/types.h>
#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/namei.h>
#include <linux/vfs.h>
#include <linux/slab.h>
#include <linux/pagemap.h>
#include <linux/time.h>
#include <linux/parser.h>
#include <linux/sysfs.h>
#include <linux/module.h>
#include <linux/seq_file.h>
#include <linux/mount.h>
#include <asm/ebcdic.h>
#include "hypfs.h"

#define HYPFS_MAGIC 0x687970	/* ASCII 'hyp' */
#define TMP_SIZE 64		/* size of temporary buffers */

static struct dentry *hypfs_create_update_file(struct super_block *sb,
					       struct dentry *dir);

struct hypfs_sb_info {
	kuid_t uid;			/* uid used for files and dirs */
	kgid_t gid;			/* gid used for files and dirs */
	struct dentry *update_file;	/* file to trigger update */
	time_t last_update;		/* last update time in secs since 1970 */
	struct mutex lock;		/* lock to protect update process */
};

static const struct file_operations hypfs_file_ops;
static struct file_system_type hypfs_type;
static const struct super_operations hypfs_s_ops;

/* start of list of all dentries, which have to be deleted on update */
static struct dentry *hypfs_last_dentry;

static void hypfs_update_update(struct super_block *sb)
{
	struct hypfs_sb_info *sb_info = sb->s_fs_info;
	struct inode *inode = sb_info->update_file->d_inode;

	sb_info->last_update = get_seconds();
	inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
}

/* directory tree removal functions */

static void hypfs_add_dentry(struct dentry *dentry)
{
	dentry->d_fsdata = hypfs_last_dentry;
	hypfs_last_dentry = dentry;
}

static inline int hypfs_positive(struct dentry *dentry)
{
	return dentry->d_inode && !d_unhashed(dentry);
}

static void hypfs_remove(struct dentry *dentry)
{
	struct dentry *parent;

	parent = dentry->d_parent;
	mutex_lock(&parent->d_inode->i_mutex);
	if (hypfs_positive(dentry)) {
		if (S_ISDIR(dentry->d_inode->i_mode))
			simple_rmdir(parent->d_inode, dentry);
		else
			simple_unlink(parent->d_inode, dentry);
	}
	d_delete(dentry);
	dput(dentry);
	mutex_unlock(&parent->d_inode->i_mutex);
}

static void hypfs_delete_tree(struct dentry *root)
{
	while (hypfs_last_dentry) {
		struct dentry *next_dentry;
		next_dentry = hypfs_last_dentry->d_fsdata;
		hypfs_remove(hypfs_last_dentry);
		hypfs_last_dentry = next_dentry;
	}
}

static struct inode *hypfs_make_inode(struct super_block *sb, umode_t mode)
{
	struct inode *ret = new_inode(sb);

	if (ret) {
		struct hypfs_sb_info *hypfs_info = sb->s_fs_info;
		ret->i_ino = get_next_ino();
		ret->i_mode = mode;
		ret->i_uid = hypfs_info->uid;
		ret->i_gid = hypfs_info->gid;
		ret->i_atime = ret->i_mtime = ret->i_ctime = CURRENT_TIME;
		if (S_ISDIR(mode))
			set_nlink(ret, 2);
	}
	return ret;
}

static void hypfs_evict_inode(struct inode *inode)
{
	clear_inode(inode);
	kfree(inode->i_private);
}

static int hypfs_open(struct inode *inode, struct file *filp)
{
	char *data = filp->f_path.dentry->d_inode->i_private;
	struct hypfs_sb_info *fs_info;

	if (filp->f_mode & FMODE_WRITE) {
		if (!(inode->i_mode & S_IWUGO))
			return -EACCES;
	}
	if (filp->f_mode & FMODE_READ) {
		if (!(inode->i_mode & S_IRUGO))
			return -EACCES;
	}

	fs_info = inode->i_sb->s_fs_info;
	if(data) {
		mutex_lock(&fs_info->lock);
		filp->private_data = kstrdup(data, GFP_KERNEL);
		if (!filp->private_data) {
			mutex_unlock(&fs_info->lock);
			return -ENOMEM;
		}
		mutex_unlock(&fs_info->lock);
	}
	return nonseekable_open(inode, filp);
}

static ssize_t hypfs_aio_read(struct kiocb *iocb, const struct iovec *iov,
			      unsigned long nr_segs, loff_t offset)
{
	char *data;
	ssize_t ret;
	struct file *filp = iocb->ki_filp;
	/* XXX: temporary */
	char __user *buf = iov[0].iov_base;
	size_t count = iov[0].iov_len;

	if (nr_segs != 1)
		return -EINVAL;

	data = filp->private_data;
	ret = simple_read_from_buffer(buf, count, &offset, data, strlen(data));
	if (ret <= 0)
		return ret;

	iocb->ki_pos += ret;
	file_accessed(filp);

	return ret;
}
static ssize_t hypfs_aio_write(struct kiocb *iocb, const struct iovec *iov,
			      unsigned long nr_segs, loff_t offset)
{
	int rc;
	struct super_block *sb;
	struct hypfs_sb_info *fs_info;
	size_t count = iov_length(iov, nr_segs);

	sb = iocb->ki_filp->f_path.dentry->d_inode->i_sb;
	fs_info = sb->s_fs_info;
	/*
	 * Currently we only allow one update per second for two reasons:
	 * 1. diag 204 is VERY expensive
	 * 2. If several processes do updates in parallel and then read the
	 *    hypfs data, the likelihood of collisions is reduced, if we restrict
	 *    the minimum update interval. A collision occurs, if during the
	 *    data gathering of one process another process triggers an update
	 *    If the first process wants to ensure consistent data, it has
	 *    to restart data collection in this case.
	 */
	mutex_lock(&fs_info->lock);
	if (fs_info->last_update == get_seconds()) {
		rc = -EBUSY;
		goto out;
	}
	hypfs_delete_tree(sb->s_root);
	if (MACHINE_IS_VM)
		rc = hypfs_vm_create_files(sb, sb->s_root);
	else
		rc = hypfs_diag_create_files(sb, sb->s_root);
	if (rc) {
		pr_err("Updating the hypfs tree failed\n");
		hypfs_delete_tree(sb->s_root);
		goto out;
	}
	hypfs_update_update(sb);
	rc = count;
out:
	mutex_unlock(&fs_info->lock);
	return rc;
}

static int hypfs_release(struct inode *inode, struct file *filp)
{
	kfree(filp->private_data);
	return 0;
}

enum { opt_uid, opt_gid, opt_err };

static const match_table_t hypfs_tokens = {
	{opt_uid, "uid=%u"},
	{opt_gid, "gid=%u"},
	{opt_err, NULL}
};

static int hypfs_parse_options(char *options, struct super_block *sb)
{
	char *str;
	substring_t args[MAX_OPT_ARGS];
	kuid_t uid;
	kgid_t gid;

	if (!options)
		return 0;
	while ((str = strsep(&options, ",")) != NULL) {
		int token, option;
		struct hypfs_sb_info *hypfs_info = sb->s_fs_info;

		if (!*str)
			continue;
		token = match_token(str, hypfs_tokens, args);
		switch (token) {
		case opt_uid:
			if (match_int(&args[0], &option))
				return -EINVAL;
			uid = make_kuid(current_user_ns(), option);
			if (!uid_valid(uid))
				return -EINVAL;
			hypfs_info->uid = uid;
			break;
		case opt_gid:
			if (match_int(&args[0], &option))
				return -EINVAL;
			gid = make_kgid(current_user_ns(), option);
			if (!gid_valid(gid))
				return -EINVAL;
			hypfs_info->gid = gid;
			break;
		case opt_err:
		default:
			pr_err("%s is not a valid mount option\n", str);
			return -EINVAL;
		}
	}
	return 0;
}

static int hypfs_show_options(struct seq_file *s, struct dentry *root)
{
	struct hypfs_sb_info *hypfs_info = root->d_sb->s_fs_info;

	seq_printf(s, ",uid=%u", from_kuid_munged(&init_user_ns, hypfs_info->uid));
	seq_printf(s, ",gid=%u", from_kgid_munged(&init_user_ns, hypfs_info->gid));
	return 0;
}

static int hypfs_fill_super(struct super_block *sb, void *data, int silent)
{
	struct inode *root_inode;
	struct dentry *root_dentry;
	int rc = 0;
	struct hypfs_sb_info *sbi;

	sbi = kzalloc(sizeof(struct hypfs_sb_info), GFP_KERNEL);
	if (!sbi)
		return -ENOMEM;
	mutex_init(&sbi->lock);
	sbi->uid = current_uid();
	sbi->gid = current_gid();
	sb->s_fs_info = sbi;
	sb->s_blocksize = PAGE_CACHE_SIZE;
	sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
	sb->s_magic = HYPFS_MAGIC;
	sb->s_op = &hypfs_s_ops;
	if (hypfs_parse_options(data, sb))
		return -EINVAL;
	root_inode = hypfs_make_inode(sb, S_IFDIR | 0755);
	if (!root_inode)
		return -ENOMEM;
	root_inode->i_op = &simple_dir_inode_operations;
	root_inode->i_fop = &simple_dir_operations;
	sb->s_root = root_dentry = d_make_root(root_inode);
	if (!root_dentry)
		return -ENOMEM;
	if (MACHINE_IS_VM)
		rc = hypfs_vm_create_files(sb, root_dentry);
	else
		rc = hypfs_diag_create_files(sb, root_dentry);
	if (rc)
		return rc;
	sbi->update_file = hypfs_create_update_file(sb, root_dentry);
	if (IS_ERR(sbi->update_file))
		return PTR_ERR(sbi->update_file);
	hypfs_update_update(sb);
	pr_info("Hypervisor filesystem mounted\n");
	return 0;
}

static struct dentry *hypfs_mount(struct file_system_type *fst, int flags,
			const char *devname, void *data)
{
	return mount_single(fst, flags, data, hypfs_fill_super);
}

static void hypfs_kill_super(struct super_block *sb)
{
	struct hypfs_sb_info *sb_info = sb->s_fs_info;

	if (sb->s_root)
		hypfs_delete_tree(sb->s_root);
	if (sb_info->update_file)
		hypfs_remove(sb_info->update_file);
	kfree(sb->s_fs_info);
	sb->s_fs_info = NULL;
	kill_litter_super(sb);
}

static struct dentry *hypfs_create_file(struct super_block *sb,
					struct dentry *parent, const char *name,
					char *data, umode_t mode)
{
	struct dentry *dentry;
	struct inode *inode;

	mutex_lock(&parent->d_inode->i_mutex);
	dentry = lookup_one_len(name, parent, strlen(name));
	if (IS_ERR(dentry)) {
		dentry = ERR_PTR(-ENOMEM);
		goto fail;
	}
	inode = hypfs_make_inode(sb, mode);
	if (!inode) {
		dput(dentry);
		dentry = ERR_PTR(-ENOMEM);
		goto fail;
	}
	if (S_ISREG(mode)) {
		inode->i_fop = &hypfs_file_ops;
		if (data)
			inode->i_size = strlen(data);
		else
			inode->i_size = 0;
	} else if (S_ISDIR(mode)) {
		inode->i_op = &simple_dir_inode_operations;
		inode->i_fop = &simple_dir_operations;
		inc_nlink(parent->d_inode);
	} else
		BUG();
	inode->i_private = data;
	d_instantiate(dentry, inode);
	dget(dentry);
fail:
	mutex_unlock(&parent->d_inode->i_mutex);
	return dentry;
}

struct dentry *hypfs_mkdir(struct super_block *sb, struct dentry *parent,
			   const char *name)
{
	struct dentry *dentry;

	dentry = hypfs_create_file(sb, parent, name, NULL, S_IFDIR | DIR_MODE);
	if (IS_ERR(dentry))
		return dentry;
	hypfs_add_dentry(dentry);
	return dentry;
}

static struct dentry *hypfs_create_update_file(struct super_block *sb,
					       struct dentry *dir)
{
	struct dentry *dentry;

	dentry = hypfs_create_file(sb, dir, "update", NULL,
				   S_IFREG | UPDATE_FILE_MODE);
	/*
	 * We do not put the update file on the 'delete' list with
	 * hypfs_add_dentry(), since it should not be removed when the tree
	 * is updated.
	 */
	return dentry;
}

struct dentry *hypfs_create_u64(struct super_block *sb, struct dentry *dir,
				const char *name, __u64 value)
{
	char *buffer;
	char tmp[TMP_SIZE];
	struct dentry *dentry;

	snprintf(tmp, TMP_SIZE, "%llu\n", (unsigned long long int)value);
	buffer = kstrdup(tmp, GFP_KERNEL);
	if (!buffer)
		return ERR_PTR(-ENOMEM);
	dentry =
	    hypfs_create_file(sb, dir, name, buffer, S_IFREG | REG_FILE_MODE);
	if (IS_ERR(dentry)) {
		kfree(buffer);
		return ERR_PTR(-ENOMEM);
	}
	hypfs_add_dentry(dentry);
	return dentry;
}

struct dentry *hypfs_create_str(struct super_block *sb, struct dentry *dir,
				const char *name, char *string)
{
	char *buffer;
	struct dentry *dentry;

	buffer = kmalloc(strlen(string) + 2, GFP_KERNEL);
	if (!buffer)
		return ERR_PTR(-ENOMEM);
	sprintf(buffer, "%s\n", string);
	dentry =
	    hypfs_create_file(sb, dir, name, buffer, S_IFREG | REG_FILE_MODE);
	if (IS_ERR(dentry)) {
		kfree(buffer);
		return ERR_PTR(-ENOMEM);
	}
	hypfs_add_dentry(dentry);
	return dentry;
}

static const struct file_operations hypfs_file_ops = {
	.open		= hypfs_open,
	.release	= hypfs_release,
	.read		= do_sync_read,
	.write		= do_sync_write,
	.aio_read	= hypfs_aio_read,
	.aio_write	= hypfs_aio_write,
	.llseek		= no_llseek,
};

static struct file_system_type hypfs_type = {
	.owner		= THIS_MODULE,
	.name		= "s390_hypfs",
	.mount		= hypfs_mount,
	.kill_sb	= hypfs_kill_super
};

static const struct super_operations hypfs_s_ops = {
	.statfs		= simple_statfs,
	.evict_inode	= hypfs_evict_inode,
	.show_options	= hypfs_show_options,
};

static struct kobject *s390_kobj;

static int __init hypfs_init(void)
{
	int rc;

	rc = hypfs_dbfs_init();
	if (rc)
		return rc;
	if (hypfs_diag_init()) {
		rc = -ENODATA;
		goto fail_dbfs_exit;
	}
	if (hypfs_vm_init()) {
		rc = -ENODATA;
		goto fail_hypfs_diag_exit;
	}
	s390_kobj = kobject_create_and_add("s390", hypervisor_kobj);
	if (!s390_kobj) {
		rc = -ENOMEM;
		goto fail_hypfs_vm_exit;
	}
	rc = register_filesystem(&hypfs_type);
	if (rc)
		goto fail_filesystem;
	return 0;

fail_filesystem:
	kobject_put(s390_kobj);
fail_hypfs_vm_exit:
	hypfs_vm_exit();
fail_hypfs_diag_exit:
	hypfs_diag_exit();
fail_dbfs_exit:
	hypfs_dbfs_exit();
	pr_err("Initialization of hypfs failed with rc=%i\n", rc);
	return rc;
}

static void __exit hypfs_exit(void)
{
	hypfs_diag_exit();
	hypfs_vm_exit();
	hypfs_dbfs_exit();
	unregister_filesystem(&hypfs_type);
	kobject_put(s390_kobj);
}

module_init(hypfs_init)
module_exit(hypfs_exit)

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Michael Holzheu <holzheu@de.ibm.com>");
MODULE_DESCRIPTION("s390 Hypervisor Filesystem");