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 * License: GPL
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/init.h>
23 #include <linux/kobject.h>
24 #include <linux/seq_file.h>
25 #include <linux/mount.h>
26 #include <linux/uio.h>
27 #include <asm/ebcdic.h>
28 #include "hypfs.h"
29
30 #define HYPFS_MAGIC 0x687970 /* ASCII 'hyp' */
31 #define TMP_SIZE 64 /* size of temporary buffers */
32
33 static struct dentry *hypfs_create_update_file(struct dentry *dir);
34
35 struct hypfs_sb_info {
36 kuid_t uid; /* uid used for files and dirs */
37 kgid_t gid; /* gid used for files and dirs */
38 struct dentry *update_file; /* file to trigger update */
39 time_t last_update; /* last update time in secs since 1970 */
40 struct mutex lock; /* lock to protect update process */
41 };
42
43 static const struct file_operations hypfs_file_ops;
44 static struct file_system_type hypfs_type;
45 static const struct super_operations hypfs_s_ops;
46
47 /* start of list of all dentries, which have to be deleted on update */
48 static struct dentry *hypfs_last_dentry;
49
hypfs_update_update(struct super_block * sb)50 static void hypfs_update_update(struct super_block *sb)
51 {
52 struct hypfs_sb_info *sb_info = sb->s_fs_info;
53 struct inode *inode = d_inode(sb_info->update_file);
54
55 sb_info->last_update = get_seconds();
56 inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode);
57 }
58
59 /* directory tree removal functions */
60
hypfs_add_dentry(struct dentry * dentry)61 static void hypfs_add_dentry(struct dentry *dentry)
62 {
63 dentry->d_fsdata = hypfs_last_dentry;
64 hypfs_last_dentry = dentry;
65 }
66
hypfs_remove(struct dentry * dentry)67 static void hypfs_remove(struct dentry *dentry)
68 {
69 struct dentry *parent;
70
71 parent = dentry->d_parent;
72 inode_lock(d_inode(parent));
73 if (simple_positive(dentry)) {
74 if (d_is_dir(dentry))
75 simple_rmdir(d_inode(parent), dentry);
76 else
77 simple_unlink(d_inode(parent), dentry);
78 }
79 d_delete(dentry);
80 dput(dentry);
81 inode_unlock(d_inode(parent));
82 }
83
hypfs_delete_tree(struct dentry * root)84 static void hypfs_delete_tree(struct dentry *root)
85 {
86 while (hypfs_last_dentry) {
87 struct dentry *next_dentry;
88 next_dentry = hypfs_last_dentry->d_fsdata;
89 hypfs_remove(hypfs_last_dentry);
90 hypfs_last_dentry = next_dentry;
91 }
92 }
93
hypfs_make_inode(struct super_block * sb,umode_t mode)94 static struct inode *hypfs_make_inode(struct super_block *sb, umode_t mode)
95 {
96 struct inode *ret = new_inode(sb);
97
98 if (ret) {
99 struct hypfs_sb_info *hypfs_info = sb->s_fs_info;
100 ret->i_ino = get_next_ino();
101 ret->i_mode = mode;
102 ret->i_uid = hypfs_info->uid;
103 ret->i_gid = hypfs_info->gid;
104 ret->i_atime = ret->i_mtime = ret->i_ctime = current_time(ret);
105 if (S_ISDIR(mode))
106 set_nlink(ret, 2);
107 }
108 return ret;
109 }
110
hypfs_evict_inode(struct inode * inode)111 static void hypfs_evict_inode(struct inode *inode)
112 {
113 clear_inode(inode);
114 kfree(inode->i_private);
115 }
116
hypfs_open(struct inode * inode,struct file * filp)117 static int hypfs_open(struct inode *inode, struct file *filp)
118 {
119 char *data = file_inode(filp)->i_private;
120 struct hypfs_sb_info *fs_info;
121
122 if (filp->f_mode & FMODE_WRITE) {
123 if (!(inode->i_mode & S_IWUGO))
124 return -EACCES;
125 }
126 if (filp->f_mode & FMODE_READ) {
127 if (!(inode->i_mode & S_IRUGO))
128 return -EACCES;
129 }
130
131 fs_info = inode->i_sb->s_fs_info;
132 if(data) {
133 mutex_lock(&fs_info->lock);
134 filp->private_data = kstrdup(data, GFP_KERNEL);
135 if (!filp->private_data) {
136 mutex_unlock(&fs_info->lock);
137 return -ENOMEM;
138 }
139 mutex_unlock(&fs_info->lock);
140 }
141 return nonseekable_open(inode, filp);
142 }
143
hypfs_read_iter(struct kiocb * iocb,struct iov_iter * to)144 static ssize_t hypfs_read_iter(struct kiocb *iocb, struct iov_iter *to)
145 {
146 struct file *file = iocb->ki_filp;
147 char *data = file->private_data;
148 size_t available = strlen(data);
149 loff_t pos = iocb->ki_pos;
150 size_t count;
151
152 if (pos < 0)
153 return -EINVAL;
154 if (pos >= available || !iov_iter_count(to))
155 return 0;
156 count = copy_to_iter(data + pos, available - pos, to);
157 if (!count)
158 return -EFAULT;
159 iocb->ki_pos = pos + count;
160 file_accessed(file);
161 return count;
162 }
163
hypfs_write_iter(struct kiocb * iocb,struct iov_iter * from)164 static ssize_t hypfs_write_iter(struct kiocb *iocb, struct iov_iter *from)
165 {
166 int rc;
167 struct super_block *sb = file_inode(iocb->ki_filp)->i_sb;
168 struct hypfs_sb_info *fs_info = sb->s_fs_info;
169 size_t count = iov_iter_count(from);
170
171 /*
172 * Currently we only allow one update per second for two reasons:
173 * 1. diag 204 is VERY expensive
174 * 2. If several processes do updates in parallel and then read the
175 * hypfs data, the likelihood of collisions is reduced, if we restrict
176 * the minimum update interval. A collision occurs, if during the
177 * data gathering of one process another process triggers an update
178 * If the first process wants to ensure consistent data, it has
179 * to restart data collection in this case.
180 */
181 mutex_lock(&fs_info->lock);
182 if (fs_info->last_update == get_seconds()) {
183 rc = -EBUSY;
184 goto out;
185 }
186 hypfs_delete_tree(sb->s_root);
187 if (MACHINE_IS_VM)
188 rc = hypfs_vm_create_files(sb->s_root);
189 else
190 rc = hypfs_diag_create_files(sb->s_root);
191 if (rc) {
192 pr_err("Updating the hypfs tree failed\n");
193 hypfs_delete_tree(sb->s_root);
194 goto out;
195 }
196 hypfs_update_update(sb);
197 rc = count;
198 iov_iter_advance(from, count);
199 out:
200 mutex_unlock(&fs_info->lock);
201 return rc;
202 }
203
hypfs_release(struct inode * inode,struct file * filp)204 static int hypfs_release(struct inode *inode, struct file *filp)
205 {
206 kfree(filp->private_data);
207 return 0;
208 }
209
210 enum { opt_uid, opt_gid, opt_err };
211
212 static const match_table_t hypfs_tokens = {
213 {opt_uid, "uid=%u"},
214 {opt_gid, "gid=%u"},
215 {opt_err, NULL}
216 };
217
hypfs_parse_options(char * options,struct super_block * sb)218 static int hypfs_parse_options(char *options, struct super_block *sb)
219 {
220 char *str;
221 substring_t args[MAX_OPT_ARGS];
222 kuid_t uid;
223 kgid_t gid;
224
225 if (!options)
226 return 0;
227 while ((str = strsep(&options, ",")) != NULL) {
228 int token, option;
229 struct hypfs_sb_info *hypfs_info = sb->s_fs_info;
230
231 if (!*str)
232 continue;
233 token = match_token(str, hypfs_tokens, args);
234 switch (token) {
235 case opt_uid:
236 if (match_int(&args[0], &option))
237 return -EINVAL;
238 uid = make_kuid(current_user_ns(), option);
239 if (!uid_valid(uid))
240 return -EINVAL;
241 hypfs_info->uid = uid;
242 break;
243 case opt_gid:
244 if (match_int(&args[0], &option))
245 return -EINVAL;
246 gid = make_kgid(current_user_ns(), option);
247 if (!gid_valid(gid))
248 return -EINVAL;
249 hypfs_info->gid = gid;
250 break;
251 case opt_err:
252 default:
253 pr_err("%s is not a valid mount option\n", str);
254 return -EINVAL;
255 }
256 }
257 return 0;
258 }
259
hypfs_show_options(struct seq_file * s,struct dentry * root)260 static int hypfs_show_options(struct seq_file *s, struct dentry *root)
261 {
262 struct hypfs_sb_info *hypfs_info = root->d_sb->s_fs_info;
263
264 seq_printf(s, ",uid=%u", from_kuid_munged(&init_user_ns, hypfs_info->uid));
265 seq_printf(s, ",gid=%u", from_kgid_munged(&init_user_ns, hypfs_info->gid));
266 return 0;
267 }
268
hypfs_fill_super(struct super_block * sb,void * data,int silent)269 static int hypfs_fill_super(struct super_block *sb, void *data, int silent)
270 {
271 struct inode *root_inode;
272 struct dentry *root_dentry, *update_file;
273 int rc = 0;
274 struct hypfs_sb_info *sbi;
275
276 sbi = kzalloc(sizeof(struct hypfs_sb_info), GFP_KERNEL);
277 if (!sbi)
278 return -ENOMEM;
279 mutex_init(&sbi->lock);
280 sbi->uid = current_uid();
281 sbi->gid = current_gid();
282 sb->s_fs_info = sbi;
283 sb->s_blocksize = PAGE_SIZE;
284 sb->s_blocksize_bits = PAGE_SHIFT;
285 sb->s_magic = HYPFS_MAGIC;
286 sb->s_op = &hypfs_s_ops;
287 if (hypfs_parse_options(data, sb))
288 return -EINVAL;
289 root_inode = hypfs_make_inode(sb, S_IFDIR | 0755);
290 if (!root_inode)
291 return -ENOMEM;
292 root_inode->i_op = &simple_dir_inode_operations;
293 root_inode->i_fop = &simple_dir_operations;
294 sb->s_root = root_dentry = d_make_root(root_inode);
295 if (!root_dentry)
296 return -ENOMEM;
297 if (MACHINE_IS_VM)
298 rc = hypfs_vm_create_files(root_dentry);
299 else
300 rc = hypfs_diag_create_files(root_dentry);
301 if (rc)
302 return rc;
303 update_file = hypfs_create_update_file(root_dentry);
304 if (IS_ERR(update_file))
305 return PTR_ERR(update_file);
306 sbi->update_file = update_file;
307 hypfs_update_update(sb);
308 pr_info("Hypervisor filesystem mounted\n");
309 return 0;
310 }
311
hypfs_mount(struct file_system_type * fst,int flags,const char * devname,void * data)312 static struct dentry *hypfs_mount(struct file_system_type *fst, int flags,
313 const char *devname, void *data)
314 {
315 return mount_single(fst, flags, data, hypfs_fill_super);
316 }
317
hypfs_kill_super(struct super_block * sb)318 static void hypfs_kill_super(struct super_block *sb)
319 {
320 struct hypfs_sb_info *sb_info = sb->s_fs_info;
321
322 if (sb->s_root)
323 hypfs_delete_tree(sb->s_root);
324 if (sb_info && sb_info->update_file)
325 hypfs_remove(sb_info->update_file);
326 kfree(sb->s_fs_info);
327 sb->s_fs_info = NULL;
328 kill_litter_super(sb);
329 }
330
hypfs_create_file(struct dentry * parent,const char * name,char * data,umode_t mode)331 static struct dentry *hypfs_create_file(struct dentry *parent, const char *name,
332 char *data, umode_t mode)
333 {
334 struct dentry *dentry;
335 struct inode *inode;
336
337 inode_lock(d_inode(parent));
338 dentry = lookup_one_len(name, parent, strlen(name));
339 if (IS_ERR(dentry)) {
340 dentry = ERR_PTR(-ENOMEM);
341 goto fail;
342 }
343 inode = hypfs_make_inode(parent->d_sb, mode);
344 if (!inode) {
345 dput(dentry);
346 dentry = ERR_PTR(-ENOMEM);
347 goto fail;
348 }
349 if (S_ISREG(mode)) {
350 inode->i_fop = &hypfs_file_ops;
351 if (data)
352 inode->i_size = strlen(data);
353 else
354 inode->i_size = 0;
355 } else if (S_ISDIR(mode)) {
356 inode->i_op = &simple_dir_inode_operations;
357 inode->i_fop = &simple_dir_operations;
358 inc_nlink(d_inode(parent));
359 } else
360 BUG();
361 inode->i_private = data;
362 d_instantiate(dentry, inode);
363 dget(dentry);
364 fail:
365 inode_unlock(d_inode(parent));
366 return dentry;
367 }
368
hypfs_mkdir(struct dentry * parent,const char * name)369 struct dentry *hypfs_mkdir(struct dentry *parent, const char *name)
370 {
371 struct dentry *dentry;
372
373 dentry = hypfs_create_file(parent, name, NULL, S_IFDIR | DIR_MODE);
374 if (IS_ERR(dentry))
375 return dentry;
376 hypfs_add_dentry(dentry);
377 return dentry;
378 }
379
hypfs_create_update_file(struct dentry * dir)380 static struct dentry *hypfs_create_update_file(struct dentry *dir)
381 {
382 struct dentry *dentry;
383
384 dentry = hypfs_create_file(dir, "update", NULL,
385 S_IFREG | UPDATE_FILE_MODE);
386 /*
387 * We do not put the update file on the 'delete' list with
388 * hypfs_add_dentry(), since it should not be removed when the tree
389 * is updated.
390 */
391 return dentry;
392 }
393
hypfs_create_u64(struct dentry * dir,const char * name,__u64 value)394 struct dentry *hypfs_create_u64(struct dentry *dir,
395 const char *name, __u64 value)
396 {
397 char *buffer;
398 char tmp[TMP_SIZE];
399 struct dentry *dentry;
400
401 snprintf(tmp, TMP_SIZE, "%llu\n", (unsigned long long int)value);
402 buffer = kstrdup(tmp, GFP_KERNEL);
403 if (!buffer)
404 return ERR_PTR(-ENOMEM);
405 dentry =
406 hypfs_create_file(dir, name, buffer, S_IFREG | REG_FILE_MODE);
407 if (IS_ERR(dentry)) {
408 kfree(buffer);
409 return ERR_PTR(-ENOMEM);
410 }
411 hypfs_add_dentry(dentry);
412 return dentry;
413 }
414
hypfs_create_str(struct dentry * dir,const char * name,char * string)415 struct dentry *hypfs_create_str(struct dentry *dir,
416 const char *name, char *string)
417 {
418 char *buffer;
419 struct dentry *dentry;
420
421 buffer = kmalloc(strlen(string) + 2, GFP_KERNEL);
422 if (!buffer)
423 return ERR_PTR(-ENOMEM);
424 sprintf(buffer, "%s\n", string);
425 dentry =
426 hypfs_create_file(dir, name, buffer, S_IFREG | REG_FILE_MODE);
427 if (IS_ERR(dentry)) {
428 kfree(buffer);
429 return ERR_PTR(-ENOMEM);
430 }
431 hypfs_add_dentry(dentry);
432 return dentry;
433 }
434
435 static const struct file_operations hypfs_file_ops = {
436 .open = hypfs_open,
437 .release = hypfs_release,
438 .read_iter = hypfs_read_iter,
439 .write_iter = hypfs_write_iter,
440 .llseek = no_llseek,
441 };
442
443 static struct file_system_type hypfs_type = {
444 .owner = THIS_MODULE,
445 .name = "s390_hypfs",
446 .mount = hypfs_mount,
447 .kill_sb = hypfs_kill_super
448 };
449
450 static const struct super_operations hypfs_s_ops = {
451 .statfs = simple_statfs,
452 .evict_inode = hypfs_evict_inode,
453 .show_options = hypfs_show_options,
454 };
455
hypfs_init(void)456 static int __init hypfs_init(void)
457 {
458 int rc;
459
460 rc = hypfs_dbfs_init();
461 if (rc)
462 return rc;
463 if (hypfs_diag_init()) {
464 rc = -ENODATA;
465 goto fail_dbfs_exit;
466 }
467 if (hypfs_vm_init()) {
468 rc = -ENODATA;
469 goto fail_hypfs_diag_exit;
470 }
471 if (hypfs_sprp_init()) {
472 rc = -ENODATA;
473 goto fail_hypfs_vm_exit;
474 }
475 if (hypfs_diag0c_init()) {
476 rc = -ENODATA;
477 goto fail_hypfs_sprp_exit;
478 }
479 rc = sysfs_create_mount_point(hypervisor_kobj, "s390");
480 if (rc)
481 goto fail_hypfs_diag0c_exit;
482 rc = register_filesystem(&hypfs_type);
483 if (rc)
484 goto fail_filesystem;
485 return 0;
486
487 fail_filesystem:
488 sysfs_remove_mount_point(hypervisor_kobj, "s390");
489 fail_hypfs_diag0c_exit:
490 hypfs_diag0c_exit();
491 fail_hypfs_sprp_exit:
492 hypfs_sprp_exit();
493 fail_hypfs_vm_exit:
494 hypfs_vm_exit();
495 fail_hypfs_diag_exit:
496 hypfs_diag_exit();
497 fail_dbfs_exit:
498 hypfs_dbfs_exit();
499 pr_err("Initialization of hypfs failed with rc=%i\n", rc);
500 return rc;
501 }
502 device_initcall(hypfs_init)
503