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/uio.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 = d_inode(sb_info->update_file);
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_remove(struct dentry * dentry)65 static void hypfs_remove(struct dentry *dentry)
66 {
67 struct dentry *parent;
68
69 parent = dentry->d_parent;
70 mutex_lock(&d_inode(parent)->i_mutex);
71 if (simple_positive(dentry)) {
72 if (d_is_dir(dentry))
73 simple_rmdir(d_inode(parent), dentry);
74 else
75 simple_unlink(d_inode(parent), dentry);
76 }
77 d_delete(dentry);
78 dput(dentry);
79 mutex_unlock(&d_inode(parent)->i_mutex);
80 }
81
hypfs_delete_tree(struct dentry * root)82 static void hypfs_delete_tree(struct dentry *root)
83 {
84 while (hypfs_last_dentry) {
85 struct dentry *next_dentry;
86 next_dentry = hypfs_last_dentry->d_fsdata;
87 hypfs_remove(hypfs_last_dentry);
88 hypfs_last_dentry = next_dentry;
89 }
90 }
91
hypfs_make_inode(struct super_block * sb,umode_t mode)92 static struct inode *hypfs_make_inode(struct super_block *sb, umode_t mode)
93 {
94 struct inode *ret = new_inode(sb);
95
96 if (ret) {
97 struct hypfs_sb_info *hypfs_info = sb->s_fs_info;
98 ret->i_ino = get_next_ino();
99 ret->i_mode = mode;
100 ret->i_uid = hypfs_info->uid;
101 ret->i_gid = hypfs_info->gid;
102 ret->i_atime = ret->i_mtime = ret->i_ctime = CURRENT_TIME;
103 if (S_ISDIR(mode))
104 set_nlink(ret, 2);
105 }
106 return ret;
107 }
108
hypfs_evict_inode(struct inode * inode)109 static void hypfs_evict_inode(struct inode *inode)
110 {
111 clear_inode(inode);
112 kfree(inode->i_private);
113 }
114
hypfs_open(struct inode * inode,struct file * filp)115 static int hypfs_open(struct inode *inode, struct file *filp)
116 {
117 char *data = file_inode(filp)->i_private;
118 struct hypfs_sb_info *fs_info;
119
120 if (filp->f_mode & FMODE_WRITE) {
121 if (!(inode->i_mode & S_IWUGO))
122 return -EACCES;
123 }
124 if (filp->f_mode & FMODE_READ) {
125 if (!(inode->i_mode & S_IRUGO))
126 return -EACCES;
127 }
128
129 fs_info = inode->i_sb->s_fs_info;
130 if(data) {
131 mutex_lock(&fs_info->lock);
132 filp->private_data = kstrdup(data, GFP_KERNEL);
133 if (!filp->private_data) {
134 mutex_unlock(&fs_info->lock);
135 return -ENOMEM;
136 }
137 mutex_unlock(&fs_info->lock);
138 }
139 return nonseekable_open(inode, filp);
140 }
141
hypfs_read_iter(struct kiocb * iocb,struct iov_iter * to)142 static ssize_t hypfs_read_iter(struct kiocb *iocb, struct iov_iter *to)
143 {
144 struct file *file = iocb->ki_filp;
145 char *data = file->private_data;
146 size_t available = strlen(data);
147 loff_t pos = iocb->ki_pos;
148 size_t count;
149
150 if (pos < 0)
151 return -EINVAL;
152 if (pos >= available || !iov_iter_count(to))
153 return 0;
154 count = copy_to_iter(data + pos, available - pos, to);
155 if (!count)
156 return -EFAULT;
157 iocb->ki_pos = pos + count;
158 file_accessed(file);
159 return count;
160 }
161
hypfs_write_iter(struct kiocb * iocb,struct iov_iter * from)162 static ssize_t hypfs_write_iter(struct kiocb *iocb, struct iov_iter *from)
163 {
164 int rc;
165 struct super_block *sb = file_inode(iocb->ki_filp)->i_sb;
166 struct hypfs_sb_info *fs_info = sb->s_fs_info;
167 size_t count = iov_iter_count(from);
168
169 /*
170 * Currently we only allow one update per second for two reasons:
171 * 1. diag 204 is VERY expensive
172 * 2. If several processes do updates in parallel and then read the
173 * hypfs data, the likelihood of collisions is reduced, if we restrict
174 * the minimum update interval. A collision occurs, if during the
175 * data gathering of one process another process triggers an update
176 * If the first process wants to ensure consistent data, it has
177 * to restart data collection in this case.
178 */
179 mutex_lock(&fs_info->lock);
180 if (fs_info->last_update == get_seconds()) {
181 rc = -EBUSY;
182 goto out;
183 }
184 hypfs_delete_tree(sb->s_root);
185 if (MACHINE_IS_VM)
186 rc = hypfs_vm_create_files(sb->s_root);
187 else
188 rc = hypfs_diag_create_files(sb->s_root);
189 if (rc) {
190 pr_err("Updating the hypfs tree failed\n");
191 hypfs_delete_tree(sb->s_root);
192 goto out;
193 }
194 hypfs_update_update(sb);
195 rc = count;
196 iov_iter_advance(from, count);
197 out:
198 mutex_unlock(&fs_info->lock);
199 return rc;
200 }
201
hypfs_release(struct inode * inode,struct file * filp)202 static int hypfs_release(struct inode *inode, struct file *filp)
203 {
204 kfree(filp->private_data);
205 return 0;
206 }
207
208 enum { opt_uid, opt_gid, opt_err };
209
210 static const match_table_t hypfs_tokens = {
211 {opt_uid, "uid=%u"},
212 {opt_gid, "gid=%u"},
213 {opt_err, NULL}
214 };
215
hypfs_parse_options(char * options,struct super_block * sb)216 static int hypfs_parse_options(char *options, struct super_block *sb)
217 {
218 char *str;
219 substring_t args[MAX_OPT_ARGS];
220 kuid_t uid;
221 kgid_t gid;
222
223 if (!options)
224 return 0;
225 while ((str = strsep(&options, ",")) != NULL) {
226 int token, option;
227 struct hypfs_sb_info *hypfs_info = sb->s_fs_info;
228
229 if (!*str)
230 continue;
231 token = match_token(str, hypfs_tokens, args);
232 switch (token) {
233 case opt_uid:
234 if (match_int(&args[0], &option))
235 return -EINVAL;
236 uid = make_kuid(current_user_ns(), option);
237 if (!uid_valid(uid))
238 return -EINVAL;
239 hypfs_info->uid = uid;
240 break;
241 case opt_gid:
242 if (match_int(&args[0], &option))
243 return -EINVAL;
244 gid = make_kgid(current_user_ns(), option);
245 if (!gid_valid(gid))
246 return -EINVAL;
247 hypfs_info->gid = gid;
248 break;
249 case opt_err:
250 default:
251 pr_err("%s is not a valid mount option\n", str);
252 return -EINVAL;
253 }
254 }
255 return 0;
256 }
257
hypfs_show_options(struct seq_file * s,struct dentry * root)258 static int hypfs_show_options(struct seq_file *s, struct dentry *root)
259 {
260 struct hypfs_sb_info *hypfs_info = root->d_sb->s_fs_info;
261
262 seq_printf(s, ",uid=%u", from_kuid_munged(&init_user_ns, hypfs_info->uid));
263 seq_printf(s, ",gid=%u", from_kgid_munged(&init_user_ns, hypfs_info->gid));
264 return 0;
265 }
266
hypfs_fill_super(struct super_block * sb,void * data,int silent)267 static int hypfs_fill_super(struct super_block *sb, void *data, int silent)
268 {
269 struct inode *root_inode;
270 struct dentry *root_dentry, *update_file;
271 int rc = 0;
272 struct hypfs_sb_info *sbi;
273
274 sbi = kzalloc(sizeof(struct hypfs_sb_info), GFP_KERNEL);
275 if (!sbi)
276 return -ENOMEM;
277 mutex_init(&sbi->lock);
278 sbi->uid = current_uid();
279 sbi->gid = current_gid();
280 sb->s_fs_info = sbi;
281 sb->s_blocksize = PAGE_CACHE_SIZE;
282 sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
283 sb->s_magic = HYPFS_MAGIC;
284 sb->s_op = &hypfs_s_ops;
285 if (hypfs_parse_options(data, sb))
286 return -EINVAL;
287 root_inode = hypfs_make_inode(sb, S_IFDIR | 0755);
288 if (!root_inode)
289 return -ENOMEM;
290 root_inode->i_op = &simple_dir_inode_operations;
291 root_inode->i_fop = &simple_dir_operations;
292 sb->s_root = root_dentry = d_make_root(root_inode);
293 if (!root_dentry)
294 return -ENOMEM;
295 if (MACHINE_IS_VM)
296 rc = hypfs_vm_create_files(root_dentry);
297 else
298 rc = hypfs_diag_create_files(root_dentry);
299 if (rc)
300 return rc;
301 update_file = hypfs_create_update_file(root_dentry);
302 if (IS_ERR(update_file))
303 return PTR_ERR(update_file);
304 sbi->update_file = update_file;
305 hypfs_update_update(sb);
306 pr_info("Hypervisor filesystem mounted\n");
307 return 0;
308 }
309
hypfs_mount(struct file_system_type * fst,int flags,const char * devname,void * data)310 static struct dentry *hypfs_mount(struct file_system_type *fst, int flags,
311 const char *devname, void *data)
312 {
313 return mount_single(fst, flags, data, hypfs_fill_super);
314 }
315
hypfs_kill_super(struct super_block * sb)316 static void hypfs_kill_super(struct super_block *sb)
317 {
318 struct hypfs_sb_info *sb_info = sb->s_fs_info;
319
320 if (sb->s_root)
321 hypfs_delete_tree(sb->s_root);
322 if (sb_info && sb_info->update_file)
323 hypfs_remove(sb_info->update_file);
324 kfree(sb->s_fs_info);
325 sb->s_fs_info = NULL;
326 kill_litter_super(sb);
327 }
328
hypfs_create_file(struct dentry * parent,const char * name,char * data,umode_t mode)329 static struct dentry *hypfs_create_file(struct dentry *parent, const char *name,
330 char *data, umode_t mode)
331 {
332 struct dentry *dentry;
333 struct inode *inode;
334
335 mutex_lock(&d_inode(parent)->i_mutex);
336 dentry = lookup_one_len(name, parent, strlen(name));
337 if (IS_ERR(dentry)) {
338 dentry = ERR_PTR(-ENOMEM);
339 goto fail;
340 }
341 inode = hypfs_make_inode(parent->d_sb, mode);
342 if (!inode) {
343 dput(dentry);
344 dentry = ERR_PTR(-ENOMEM);
345 goto fail;
346 }
347 if (S_ISREG(mode)) {
348 inode->i_fop = &hypfs_file_ops;
349 if (data)
350 inode->i_size = strlen(data);
351 else
352 inode->i_size = 0;
353 } else if (S_ISDIR(mode)) {
354 inode->i_op = &simple_dir_inode_operations;
355 inode->i_fop = &simple_dir_operations;
356 inc_nlink(d_inode(parent));
357 } else
358 BUG();
359 inode->i_private = data;
360 d_instantiate(dentry, inode);
361 dget(dentry);
362 fail:
363 mutex_unlock(&d_inode(parent)->i_mutex);
364 return dentry;
365 }
366
hypfs_mkdir(struct dentry * parent,const char * name)367 struct dentry *hypfs_mkdir(struct dentry *parent, const char *name)
368 {
369 struct dentry *dentry;
370
371 dentry = hypfs_create_file(parent, name, NULL, S_IFDIR | DIR_MODE);
372 if (IS_ERR(dentry))
373 return dentry;
374 hypfs_add_dentry(dentry);
375 return dentry;
376 }
377
hypfs_create_update_file(struct dentry * dir)378 static struct dentry *hypfs_create_update_file(struct dentry *dir)
379 {
380 struct dentry *dentry;
381
382 dentry = hypfs_create_file(dir, "update", NULL,
383 S_IFREG | UPDATE_FILE_MODE);
384 /*
385 * We do not put the update file on the 'delete' list with
386 * hypfs_add_dentry(), since it should not be removed when the tree
387 * is updated.
388 */
389 return dentry;
390 }
391
hypfs_create_u64(struct dentry * dir,const char * name,__u64 value)392 struct dentry *hypfs_create_u64(struct dentry *dir,
393 const char *name, __u64 value)
394 {
395 char *buffer;
396 char tmp[TMP_SIZE];
397 struct dentry *dentry;
398
399 snprintf(tmp, TMP_SIZE, "%llu\n", (unsigned long long int)value);
400 buffer = kstrdup(tmp, GFP_KERNEL);
401 if (!buffer)
402 return ERR_PTR(-ENOMEM);
403 dentry =
404 hypfs_create_file(dir, name, buffer, S_IFREG | REG_FILE_MODE);
405 if (IS_ERR(dentry)) {
406 kfree(buffer);
407 return ERR_PTR(-ENOMEM);
408 }
409 hypfs_add_dentry(dentry);
410 return dentry;
411 }
412
hypfs_create_str(struct dentry * dir,const char * name,char * string)413 struct dentry *hypfs_create_str(struct dentry *dir,
414 const char *name, char *string)
415 {
416 char *buffer;
417 struct dentry *dentry;
418
419 buffer = kmalloc(strlen(string) + 2, GFP_KERNEL);
420 if (!buffer)
421 return ERR_PTR(-ENOMEM);
422 sprintf(buffer, "%s\n", string);
423 dentry =
424 hypfs_create_file(dir, name, buffer, S_IFREG | REG_FILE_MODE);
425 if (IS_ERR(dentry)) {
426 kfree(buffer);
427 return ERR_PTR(-ENOMEM);
428 }
429 hypfs_add_dentry(dentry);
430 return dentry;
431 }
432
433 static const struct file_operations hypfs_file_ops = {
434 .open = hypfs_open,
435 .release = hypfs_release,
436 .read_iter = hypfs_read_iter,
437 .write_iter = hypfs_write_iter,
438 .llseek = no_llseek,
439 };
440
441 static struct file_system_type hypfs_type = {
442 .owner = THIS_MODULE,
443 .name = "s390_hypfs",
444 .mount = hypfs_mount,
445 .kill_sb = hypfs_kill_super
446 };
447 MODULE_ALIAS_FS("s390_hypfs");
448
449 static const struct super_operations hypfs_s_ops = {
450 .statfs = simple_statfs,
451 .evict_inode = hypfs_evict_inode,
452 .show_options = hypfs_show_options,
453 };
454
hypfs_init(void)455 static int __init hypfs_init(void)
456 {
457 int rc;
458
459 rc = hypfs_dbfs_init();
460 if (rc)
461 return rc;
462 if (hypfs_diag_init()) {
463 rc = -ENODATA;
464 goto fail_dbfs_exit;
465 }
466 if (hypfs_vm_init()) {
467 rc = -ENODATA;
468 goto fail_hypfs_diag_exit;
469 }
470 if (hypfs_sprp_init()) {
471 rc = -ENODATA;
472 goto fail_hypfs_vm_exit;
473 }
474 if (hypfs_diag0c_init()) {
475 rc = -ENODATA;
476 goto fail_hypfs_sprp_exit;
477 }
478 rc = sysfs_create_mount_point(hypervisor_kobj, "s390");
479 if (rc)
480 goto fail_hypfs_diag0c_exit;
481 rc = register_filesystem(&hypfs_type);
482 if (rc)
483 goto fail_filesystem;
484 return 0;
485
486 fail_filesystem:
487 sysfs_remove_mount_point(hypervisor_kobj, "s390");
488 fail_hypfs_diag0c_exit:
489 hypfs_diag0c_exit();
490 fail_hypfs_sprp_exit:
491 hypfs_sprp_exit();
492 fail_hypfs_vm_exit:
493 hypfs_vm_exit();
494 fail_hypfs_diag_exit:
495 hypfs_diag_exit();
496 fail_dbfs_exit:
497 hypfs_dbfs_exit();
498 pr_err("Initialization of hypfs failed with rc=%i\n", rc);
499 return rc;
500 }
501
hypfs_exit(void)502 static void __exit hypfs_exit(void)
503 {
504 unregister_filesystem(&hypfs_type);
505 sysfs_remove_mount_point(hypervisor_kobj, "s390");
506 hypfs_diag0c_exit();
507 hypfs_sprp_exit();
508 hypfs_vm_exit();
509 hypfs_diag_exit();
510 hypfs_dbfs_exit();
511 }
512
513 module_init(hypfs_init)
514 module_exit(hypfs_exit)
515
516 MODULE_LICENSE("GPL");
517 MODULE_AUTHOR("Michael Holzheu <holzheu@de.ibm.com>");
518 MODULE_DESCRIPTION("s390 Hypervisor Filesystem");
519