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