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1 /*
2  *    Hypervisor filesystem for Linux on s390.
3  *
4  *    Copyright IBM Corp. 2006, 2008
5  *    Author(s): Michael Holzheu <holzheu@de.ibm.com>
6  */
7 
8 #define KMSG_COMPONENT "hypfs"
9 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
10 
11 #include <linux/types.h>
12 #include <linux/errno.h>
13 #include <linux/fs.h>
14 #include <linux/namei.h>
15 #include <linux/vfs.h>
16 #include <linux/slab.h>
17 #include <linux/pagemap.h>
18 #include <linux/time.h>
19 #include <linux/parser.h>
20 #include <linux/sysfs.h>
21 #include <linux/module.h>
22 #include <linux/seq_file.h>
23 #include <linux/mount.h>
24 #include <linux/aio.h>
25 #include <asm/ebcdic.h>
26 #include "hypfs.h"
27 
28 #define HYPFS_MAGIC 0x687970	/* ASCII 'hyp' */
29 #define TMP_SIZE 64		/* size of temporary buffers */
30 
31 static struct dentry *hypfs_create_update_file(struct dentry *dir);
32 
33 struct hypfs_sb_info {
34 	kuid_t uid;			/* uid used for files and dirs */
35 	kgid_t gid;			/* gid used for files and dirs */
36 	struct dentry *update_file;	/* file to trigger update */
37 	time_t last_update;		/* last update time in secs since 1970 */
38 	struct mutex lock;		/* lock to protect update process */
39 };
40 
41 static const struct file_operations hypfs_file_ops;
42 static struct file_system_type hypfs_type;
43 static const struct super_operations hypfs_s_ops;
44 
45 /* start of list of all dentries, which have to be deleted on update */
46 static struct dentry *hypfs_last_dentry;
47 
hypfs_update_update(struct super_block * sb)48 static void hypfs_update_update(struct super_block *sb)
49 {
50 	struct hypfs_sb_info *sb_info = sb->s_fs_info;
51 	struct inode *inode = sb_info->update_file->d_inode;
52 
53 	sb_info->last_update = get_seconds();
54 	inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
55 }
56 
57 /* directory tree removal functions */
58 
hypfs_add_dentry(struct dentry * dentry)59 static void hypfs_add_dentry(struct dentry *dentry)
60 {
61 	dentry->d_fsdata = hypfs_last_dentry;
62 	hypfs_last_dentry = dentry;
63 }
64 
hypfs_positive(struct dentry * dentry)65 static inline int hypfs_positive(struct dentry *dentry)
66 {
67 	return dentry->d_inode && !d_unhashed(dentry);
68 }
69 
hypfs_remove(struct dentry * dentry)70 static void hypfs_remove(struct dentry *dentry)
71 {
72 	struct dentry *parent;
73 
74 	parent = dentry->d_parent;
75 	mutex_lock(&parent->d_inode->i_mutex);
76 	if (hypfs_positive(dentry)) {
77 		if (S_ISDIR(dentry->d_inode->i_mode))
78 			simple_rmdir(parent->d_inode, dentry);
79 		else
80 			simple_unlink(parent->d_inode, dentry);
81 	}
82 	d_delete(dentry);
83 	dput(dentry);
84 	mutex_unlock(&parent->d_inode->i_mutex);
85 }
86 
hypfs_delete_tree(struct dentry * root)87 static void hypfs_delete_tree(struct dentry *root)
88 {
89 	while (hypfs_last_dentry) {
90 		struct dentry *next_dentry;
91 		next_dentry = hypfs_last_dentry->d_fsdata;
92 		hypfs_remove(hypfs_last_dentry);
93 		hypfs_last_dentry = next_dentry;
94 	}
95 }
96 
hypfs_make_inode(struct super_block * sb,umode_t mode)97 static struct inode *hypfs_make_inode(struct super_block *sb, umode_t mode)
98 {
99 	struct inode *ret = new_inode(sb);
100 
101 	if (ret) {
102 		struct hypfs_sb_info *hypfs_info = sb->s_fs_info;
103 		ret->i_ino = get_next_ino();
104 		ret->i_mode = mode;
105 		ret->i_uid = hypfs_info->uid;
106 		ret->i_gid = hypfs_info->gid;
107 		ret->i_atime = ret->i_mtime = ret->i_ctime = CURRENT_TIME;
108 		if (S_ISDIR(mode))
109 			set_nlink(ret, 2);
110 	}
111 	return ret;
112 }
113 
hypfs_evict_inode(struct inode * inode)114 static void hypfs_evict_inode(struct inode *inode)
115 {
116 	clear_inode(inode);
117 	kfree(inode->i_private);
118 }
119 
hypfs_open(struct inode * inode,struct file * filp)120 static int hypfs_open(struct inode *inode, struct file *filp)
121 {
122 	char *data = file_inode(filp)->i_private;
123 	struct hypfs_sb_info *fs_info;
124 
125 	if (filp->f_mode & FMODE_WRITE) {
126 		if (!(inode->i_mode & S_IWUGO))
127 			return -EACCES;
128 	}
129 	if (filp->f_mode & FMODE_READ) {
130 		if (!(inode->i_mode & S_IRUGO))
131 			return -EACCES;
132 	}
133 
134 	fs_info = inode->i_sb->s_fs_info;
135 	if(data) {
136 		mutex_lock(&fs_info->lock);
137 		filp->private_data = kstrdup(data, GFP_KERNEL);
138 		if (!filp->private_data) {
139 			mutex_unlock(&fs_info->lock);
140 			return -ENOMEM;
141 		}
142 		mutex_unlock(&fs_info->lock);
143 	}
144 	return nonseekable_open(inode, filp);
145 }
146 
hypfs_aio_read(struct kiocb * iocb,const struct iovec * iov,unsigned long nr_segs,loff_t offset)147 static ssize_t hypfs_aio_read(struct kiocb *iocb, const struct iovec *iov,
148 			      unsigned long nr_segs, loff_t offset)
149 {
150 	char *data;
151 	ssize_t ret;
152 	struct file *filp = iocb->ki_filp;
153 	/* XXX: temporary */
154 	char __user *buf = iov[0].iov_base;
155 	size_t count = iov[0].iov_len;
156 
157 	if (nr_segs != 1)
158 		return -EINVAL;
159 
160 	data = filp->private_data;
161 	ret = simple_read_from_buffer(buf, count, &offset, data, strlen(data));
162 	if (ret <= 0)
163 		return ret;
164 
165 	iocb->ki_pos += ret;
166 	file_accessed(filp);
167 
168 	return ret;
169 }
hypfs_aio_write(struct kiocb * iocb,const struct iovec * iov,unsigned long nr_segs,loff_t offset)170 static ssize_t hypfs_aio_write(struct kiocb *iocb, const struct iovec *iov,
171 			      unsigned long nr_segs, loff_t offset)
172 {
173 	int rc;
174 	struct super_block *sb = file_inode(iocb->ki_filp)->i_sb;
175 	struct hypfs_sb_info *fs_info = sb->s_fs_info;
176 	size_t count = iov_length(iov, nr_segs);
177 
178 	/*
179 	 * Currently we only allow one update per second for two reasons:
180 	 * 1. diag 204 is VERY expensive
181 	 * 2. If several processes do updates in parallel and then read the
182 	 *    hypfs data, the likelihood of collisions is reduced, if we restrict
183 	 *    the minimum update interval. A collision occurs, if during the
184 	 *    data gathering of one process another process triggers an update
185 	 *    If the first process wants to ensure consistent data, it has
186 	 *    to restart data collection in this case.
187 	 */
188 	mutex_lock(&fs_info->lock);
189 	if (fs_info->last_update == get_seconds()) {
190 		rc = -EBUSY;
191 		goto out;
192 	}
193 	hypfs_delete_tree(sb->s_root);
194 	if (MACHINE_IS_VM)
195 		rc = hypfs_vm_create_files(sb->s_root);
196 	else
197 		rc = hypfs_diag_create_files(sb->s_root);
198 	if (rc) {
199 		pr_err("Updating the hypfs tree failed\n");
200 		hypfs_delete_tree(sb->s_root);
201 		goto out;
202 	}
203 	hypfs_update_update(sb);
204 	rc = count;
205 out:
206 	mutex_unlock(&fs_info->lock);
207 	return rc;
208 }
209 
hypfs_release(struct inode * inode,struct file * filp)210 static int hypfs_release(struct inode *inode, struct file *filp)
211 {
212 	kfree(filp->private_data);
213 	return 0;
214 }
215 
216 enum { opt_uid, opt_gid, opt_err };
217 
218 static const match_table_t hypfs_tokens = {
219 	{opt_uid, "uid=%u"},
220 	{opt_gid, "gid=%u"},
221 	{opt_err, NULL}
222 };
223 
hypfs_parse_options(char * options,struct super_block * sb)224 static int hypfs_parse_options(char *options, struct super_block *sb)
225 {
226 	char *str;
227 	substring_t args[MAX_OPT_ARGS];
228 	kuid_t uid;
229 	kgid_t gid;
230 
231 	if (!options)
232 		return 0;
233 	while ((str = strsep(&options, ",")) != NULL) {
234 		int token, option;
235 		struct hypfs_sb_info *hypfs_info = sb->s_fs_info;
236 
237 		if (!*str)
238 			continue;
239 		token = match_token(str, hypfs_tokens, args);
240 		switch (token) {
241 		case opt_uid:
242 			if (match_int(&args[0], &option))
243 				return -EINVAL;
244 			uid = make_kuid(current_user_ns(), option);
245 			if (!uid_valid(uid))
246 				return -EINVAL;
247 			hypfs_info->uid = uid;
248 			break;
249 		case opt_gid:
250 			if (match_int(&args[0], &option))
251 				return -EINVAL;
252 			gid = make_kgid(current_user_ns(), option);
253 			if (!gid_valid(gid))
254 				return -EINVAL;
255 			hypfs_info->gid = gid;
256 			break;
257 		case opt_err:
258 		default:
259 			pr_err("%s is not a valid mount option\n", str);
260 			return -EINVAL;
261 		}
262 	}
263 	return 0;
264 }
265 
hypfs_show_options(struct seq_file * s,struct dentry * root)266 static int hypfs_show_options(struct seq_file *s, struct dentry *root)
267 {
268 	struct hypfs_sb_info *hypfs_info = root->d_sb->s_fs_info;
269 
270 	seq_printf(s, ",uid=%u", from_kuid_munged(&init_user_ns, hypfs_info->uid));
271 	seq_printf(s, ",gid=%u", from_kgid_munged(&init_user_ns, hypfs_info->gid));
272 	return 0;
273 }
274 
hypfs_fill_super(struct super_block * sb,void * data,int silent)275 static int hypfs_fill_super(struct super_block *sb, void *data, int silent)
276 {
277 	struct inode *root_inode;
278 	struct dentry *root_dentry;
279 	int rc = 0;
280 	struct hypfs_sb_info *sbi;
281 
282 	sbi = kzalloc(sizeof(struct hypfs_sb_info), GFP_KERNEL);
283 	if (!sbi)
284 		return -ENOMEM;
285 	mutex_init(&sbi->lock);
286 	sbi->uid = current_uid();
287 	sbi->gid = current_gid();
288 	sb->s_fs_info = sbi;
289 	sb->s_blocksize = PAGE_CACHE_SIZE;
290 	sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
291 	sb->s_magic = HYPFS_MAGIC;
292 	sb->s_op = &hypfs_s_ops;
293 	if (hypfs_parse_options(data, sb))
294 		return -EINVAL;
295 	root_inode = hypfs_make_inode(sb, S_IFDIR | 0755);
296 	if (!root_inode)
297 		return -ENOMEM;
298 	root_inode->i_op = &simple_dir_inode_operations;
299 	root_inode->i_fop = &simple_dir_operations;
300 	sb->s_root = root_dentry = d_make_root(root_inode);
301 	if (!root_dentry)
302 		return -ENOMEM;
303 	if (MACHINE_IS_VM)
304 		rc = hypfs_vm_create_files(root_dentry);
305 	else
306 		rc = hypfs_diag_create_files(root_dentry);
307 	if (rc)
308 		return rc;
309 	sbi->update_file = hypfs_create_update_file(root_dentry);
310 	if (IS_ERR(sbi->update_file))
311 		return PTR_ERR(sbi->update_file);
312 	hypfs_update_update(sb);
313 	pr_info("Hypervisor filesystem mounted\n");
314 	return 0;
315 }
316 
hypfs_mount(struct file_system_type * fst,int flags,const char * devname,void * data)317 static struct dentry *hypfs_mount(struct file_system_type *fst, int flags,
318 			const char *devname, void *data)
319 {
320 	return mount_single(fst, flags, data, hypfs_fill_super);
321 }
322 
hypfs_kill_super(struct super_block * sb)323 static void hypfs_kill_super(struct super_block *sb)
324 {
325 	struct hypfs_sb_info *sb_info = sb->s_fs_info;
326 
327 	if (sb->s_root)
328 		hypfs_delete_tree(sb->s_root);
329 	if (sb_info->update_file)
330 		hypfs_remove(sb_info->update_file);
331 	kfree(sb->s_fs_info);
332 	sb->s_fs_info = NULL;
333 	kill_litter_super(sb);
334 }
335 
hypfs_create_file(struct dentry * parent,const char * name,char * data,umode_t mode)336 static struct dentry *hypfs_create_file(struct dentry *parent, const char *name,
337 					char *data, umode_t mode)
338 {
339 	struct dentry *dentry;
340 	struct inode *inode;
341 
342 	mutex_lock(&parent->d_inode->i_mutex);
343 	dentry = lookup_one_len(name, parent, strlen(name));
344 	if (IS_ERR(dentry)) {
345 		dentry = ERR_PTR(-ENOMEM);
346 		goto fail;
347 	}
348 	inode = hypfs_make_inode(parent->d_sb, mode);
349 	if (!inode) {
350 		dput(dentry);
351 		dentry = ERR_PTR(-ENOMEM);
352 		goto fail;
353 	}
354 	if (S_ISREG(mode)) {
355 		inode->i_fop = &hypfs_file_ops;
356 		if (data)
357 			inode->i_size = strlen(data);
358 		else
359 			inode->i_size = 0;
360 	} else if (S_ISDIR(mode)) {
361 		inode->i_op = &simple_dir_inode_operations;
362 		inode->i_fop = &simple_dir_operations;
363 		inc_nlink(parent->d_inode);
364 	} else
365 		BUG();
366 	inode->i_private = data;
367 	d_instantiate(dentry, inode);
368 	dget(dentry);
369 fail:
370 	mutex_unlock(&parent->d_inode->i_mutex);
371 	return dentry;
372 }
373 
hypfs_mkdir(struct dentry * parent,const char * name)374 struct dentry *hypfs_mkdir(struct dentry *parent, const char *name)
375 {
376 	struct dentry *dentry;
377 
378 	dentry = hypfs_create_file(parent, name, NULL, S_IFDIR | DIR_MODE);
379 	if (IS_ERR(dentry))
380 		return dentry;
381 	hypfs_add_dentry(dentry);
382 	return dentry;
383 }
384 
hypfs_create_update_file(struct dentry * dir)385 static struct dentry *hypfs_create_update_file(struct dentry *dir)
386 {
387 	struct dentry *dentry;
388 
389 	dentry = hypfs_create_file(dir, "update", NULL,
390 				   S_IFREG | UPDATE_FILE_MODE);
391 	/*
392 	 * We do not put the update file on the 'delete' list with
393 	 * hypfs_add_dentry(), since it should not be removed when the tree
394 	 * is updated.
395 	 */
396 	return dentry;
397 }
398 
hypfs_create_u64(struct dentry * dir,const char * name,__u64 value)399 struct dentry *hypfs_create_u64(struct dentry *dir,
400 				const char *name, __u64 value)
401 {
402 	char *buffer;
403 	char tmp[TMP_SIZE];
404 	struct dentry *dentry;
405 
406 	snprintf(tmp, TMP_SIZE, "%llu\n", (unsigned long long int)value);
407 	buffer = kstrdup(tmp, GFP_KERNEL);
408 	if (!buffer)
409 		return ERR_PTR(-ENOMEM);
410 	dentry =
411 	    hypfs_create_file(dir, name, buffer, S_IFREG | REG_FILE_MODE);
412 	if (IS_ERR(dentry)) {
413 		kfree(buffer);
414 		return ERR_PTR(-ENOMEM);
415 	}
416 	hypfs_add_dentry(dentry);
417 	return dentry;
418 }
419 
hypfs_create_str(struct dentry * dir,const char * name,char * string)420 struct dentry *hypfs_create_str(struct dentry *dir,
421 				const char *name, char *string)
422 {
423 	char *buffer;
424 	struct dentry *dentry;
425 
426 	buffer = kmalloc(strlen(string) + 2, GFP_KERNEL);
427 	if (!buffer)
428 		return ERR_PTR(-ENOMEM);
429 	sprintf(buffer, "%s\n", string);
430 	dentry =
431 	    hypfs_create_file(dir, name, buffer, S_IFREG | REG_FILE_MODE);
432 	if (IS_ERR(dentry)) {
433 		kfree(buffer);
434 		return ERR_PTR(-ENOMEM);
435 	}
436 	hypfs_add_dentry(dentry);
437 	return dentry;
438 }
439 
440 static const struct file_operations hypfs_file_ops = {
441 	.open		= hypfs_open,
442 	.release	= hypfs_release,
443 	.read		= do_sync_read,
444 	.write		= do_sync_write,
445 	.aio_read	= hypfs_aio_read,
446 	.aio_write	= hypfs_aio_write,
447 	.llseek		= no_llseek,
448 };
449 
450 static struct file_system_type hypfs_type = {
451 	.owner		= THIS_MODULE,
452 	.name		= "s390_hypfs",
453 	.mount		= hypfs_mount,
454 	.kill_sb	= hypfs_kill_super
455 };
456 MODULE_ALIAS_FS("s390_hypfs");
457 
458 static const struct super_operations hypfs_s_ops = {
459 	.statfs		= simple_statfs,
460 	.evict_inode	= hypfs_evict_inode,
461 	.show_options	= hypfs_show_options,
462 };
463 
464 static struct kobject *s390_kobj;
465 
hypfs_init(void)466 static int __init hypfs_init(void)
467 {
468 	int rc;
469 
470 	rc = hypfs_dbfs_init();
471 	if (rc)
472 		return rc;
473 	if (hypfs_diag_init()) {
474 		rc = -ENODATA;
475 		goto fail_dbfs_exit;
476 	}
477 	if (hypfs_vm_init()) {
478 		rc = -ENODATA;
479 		goto fail_hypfs_diag_exit;
480 	}
481 	if (hypfs_sprp_init()) {
482 		rc = -ENODATA;
483 		goto fail_hypfs_vm_exit;
484 	}
485 	s390_kobj = kobject_create_and_add("s390", hypervisor_kobj);
486 	if (!s390_kobj) {
487 		rc = -ENOMEM;
488 		goto fail_hypfs_sprp_exit;
489 	}
490 	rc = register_filesystem(&hypfs_type);
491 	if (rc)
492 		goto fail_filesystem;
493 	return 0;
494 
495 fail_filesystem:
496 	kobject_put(s390_kobj);
497 fail_hypfs_sprp_exit:
498 	hypfs_sprp_exit();
499 fail_hypfs_vm_exit:
500 	hypfs_vm_exit();
501 fail_hypfs_diag_exit:
502 	hypfs_diag_exit();
503 fail_dbfs_exit:
504 	hypfs_dbfs_exit();
505 	pr_err("Initialization of hypfs failed with rc=%i\n", rc);
506 	return rc;
507 }
508 
hypfs_exit(void)509 static void __exit hypfs_exit(void)
510 {
511 	unregister_filesystem(&hypfs_type);
512 	kobject_put(s390_kobj);
513 	hypfs_sprp_exit();
514 	hypfs_vm_exit();
515 	hypfs_diag_exit();
516 	hypfs_dbfs_exit();
517 }
518 
519 module_init(hypfs_init)
520 module_exit(hypfs_exit)
521 
522 MODULE_LICENSE("GPL");
523 MODULE_AUTHOR("Michael Holzheu <holzheu@de.ibm.com>");
524 MODULE_DESCRIPTION("s390 Hypervisor Filesystem");
525