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