Merge tag 'v3.3.7' into 3.3/master
[zen-stable.git] / arch / s390 / hypfs / inode.c
blob8a2a887478cc770141f7f8138ee0b8cce44dda54
1 /*
2 * arch/s390/hypfs/inode.c
3 * Hypervisor filesystem for Linux on s390.
5 * Copyright IBM Corp. 2006, 2008
6 * Author(s): Michael Holzheu <holzheu@de.ibm.com>
7 */
9 #define KMSG_COMPONENT "hypfs"
10 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
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"
28 #define HYPFS_MAGIC 0x687970 /* ASCII 'hyp' */
29 #define TMP_SIZE 64 /* size of temporary buffers */
31 static struct dentry *hypfs_create_update_file(struct super_block *sb,
32 struct dentry *dir);
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 */
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;
46 /* start of list of all dentries, which have to be deleted on update */
47 static struct dentry *hypfs_last_dentry;
49 static void hypfs_update_update(struct super_block *sb)
51 struct hypfs_sb_info *sb_info = sb->s_fs_info;
52 struct inode *inode = sb_info->update_file->d_inode;
54 sb_info->last_update = get_seconds();
55 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
58 /* directory tree removal functions */
60 static void hypfs_add_dentry(struct dentry *dentry)
62 dentry->d_fsdata = hypfs_last_dentry;
63 hypfs_last_dentry = dentry;
66 static inline int hypfs_positive(struct dentry *dentry)
68 return dentry->d_inode && !d_unhashed(dentry);
71 static void hypfs_remove(struct dentry *dentry)
73 struct dentry *parent;
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);
85 d_delete(dentry);
86 dput(dentry);
87 mutex_unlock(&parent->d_inode->i_mutex);
90 static void hypfs_delete_tree(struct dentry *root)
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;
100 static struct inode *hypfs_make_inode(struct super_block *sb, umode_t mode)
102 struct inode *ret = new_inode(sb);
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);
113 return ret;
116 static void hypfs_evict_inode(struct inode *inode)
118 end_writeback(inode);
119 kfree(inode->i_private);
122 static int hypfs_open(struct inode *inode, struct file *filp)
124 char *data = filp->f_path.dentry->d_inode->i_private;
125 struct hypfs_sb_info *fs_info;
127 if (filp->f_mode & FMODE_WRITE) {
128 if (!(inode->i_mode & S_IWUGO))
129 return -EACCES;
131 if (filp->f_mode & FMODE_READ) {
132 if (!(inode->i_mode & S_IRUGO))
133 return -EACCES;
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;
144 mutex_unlock(&fs_info->lock);
146 return nonseekable_open(inode, filp);
149 static ssize_t hypfs_aio_read(struct kiocb *iocb, const struct iovec *iov,
150 unsigned long nr_segs, loff_t offset)
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;
159 if (nr_segs != 1)
160 return -EINVAL;
162 data = filp->private_data;
163 ret = simple_read_from_buffer(buf, count, &offset, data, strlen(data));
164 if (ret <= 0)
165 return ret;
167 iocb->ki_pos += ret;
168 file_accessed(filp);
170 return ret;
172 static ssize_t hypfs_aio_write(struct kiocb *iocb, const struct iovec *iov,
173 unsigned long nr_segs, loff_t offset)
175 int rc;
176 struct super_block *sb;
177 struct hypfs_sb_info *fs_info;
178 size_t count = iov_length(iov, nr_segs);
180 sb = iocb->ki_filp->f_path.dentry->d_inode->i_sb;
181 fs_info = sb->s_fs_info;
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.
192 mutex_lock(&fs_info->lock);
193 if (fs_info->last_update == get_seconds()) {
194 rc = -EBUSY;
195 goto out;
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;
207 hypfs_update_update(sb);
208 rc = count;
209 out:
210 mutex_unlock(&fs_info->lock);
211 return rc;
214 static int hypfs_release(struct inode *inode, struct file *filp)
216 kfree(filp->private_data);
217 return 0;
220 enum { opt_uid, opt_gid, opt_err };
222 static const match_table_t hypfs_tokens = {
223 {opt_uid, "uid=%u"},
224 {opt_gid, "gid=%u"},
225 {opt_err, NULL}
228 static int hypfs_parse_options(char *options, struct super_block *sb)
230 char *str;
231 substring_t args[MAX_OPT_ARGS];
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;
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;
259 return 0;
262 static int hypfs_show_options(struct seq_file *s, struct dentry *root)
264 struct hypfs_sb_info *hypfs_info = root->d_sb->s_fs_info;
266 seq_printf(s, ",uid=%u", hypfs_info->uid);
267 seq_printf(s, ",gid=%u", hypfs_info->gid);
268 return 0;
271 static int hypfs_fill_super(struct super_block *sb, void *data, int silent)
273 struct inode *root_inode;
274 struct dentry *root_dentry;
275 int rc = 0;
276 struct hypfs_sb_info *sbi;
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_alloc_root(root_inode);
297 if (!root_dentry) {
298 iput(root_inode);
299 return -ENOMEM;
301 if (MACHINE_IS_VM)
302 rc = hypfs_vm_create_files(sb, root_dentry);
303 else
304 rc = hypfs_diag_create_files(sb, root_dentry);
305 if (rc)
306 return rc;
307 sbi->update_file = hypfs_create_update_file(sb, root_dentry);
308 if (IS_ERR(sbi->update_file))
309 return PTR_ERR(sbi->update_file);
310 hypfs_update_update(sb);
311 pr_info("Hypervisor filesystem mounted\n");
312 return 0;
315 static struct dentry *hypfs_mount(struct file_system_type *fst, int flags,
316 const char *devname, void *data)
318 return mount_single(fst, flags, data, hypfs_fill_super);
321 static void hypfs_kill_super(struct super_block *sb)
323 struct hypfs_sb_info *sb_info = sb->s_fs_info;
325 if (sb->s_root)
326 hypfs_delete_tree(sb->s_root);
327 if (sb_info->update_file)
328 hypfs_remove(sb_info->update_file);
329 kfree(sb->s_fs_info);
330 sb->s_fs_info = NULL;
331 kill_litter_super(sb);
334 static struct dentry *hypfs_create_file(struct super_block *sb,
335 struct dentry *parent, const char *name,
336 char *data, umode_t mode)
338 struct dentry *dentry;
339 struct inode *inode;
341 mutex_lock(&parent->d_inode->i_mutex);
342 dentry = lookup_one_len(name, parent, strlen(name));
343 if (IS_ERR(dentry)) {
344 dentry = ERR_PTR(-ENOMEM);
345 goto fail;
347 inode = hypfs_make_inode(sb, mode);
348 if (!inode) {
349 dput(dentry);
350 dentry = ERR_PTR(-ENOMEM);
351 goto fail;
353 if (S_ISREG(mode)) {
354 inode->i_fop = &hypfs_file_ops;
355 if (data)
356 inode->i_size = strlen(data);
357 else
358 inode->i_size = 0;
359 } else if (S_ISDIR(mode)) {
360 inode->i_op = &simple_dir_inode_operations;
361 inode->i_fop = &simple_dir_operations;
362 inc_nlink(parent->d_inode);
363 } else
364 BUG();
365 inode->i_private = data;
366 d_instantiate(dentry, inode);
367 dget(dentry);
368 fail:
369 mutex_unlock(&parent->d_inode->i_mutex);
370 return dentry;
373 struct dentry *hypfs_mkdir(struct super_block *sb, struct dentry *parent,
374 const char *name)
376 struct dentry *dentry;
378 dentry = hypfs_create_file(sb, parent, name, NULL, S_IFDIR | DIR_MODE);
379 if (IS_ERR(dentry))
380 return dentry;
381 hypfs_add_dentry(dentry);
382 return dentry;
385 static struct dentry *hypfs_create_update_file(struct super_block *sb,
386 struct dentry *dir)
388 struct dentry *dentry;
390 dentry = hypfs_create_file(sb, dir, "update", NULL,
391 S_IFREG | UPDATE_FILE_MODE);
393 * We do not put the update file on the 'delete' list with
394 * hypfs_add_dentry(), since it should not be removed when the tree
395 * is updated.
397 return dentry;
400 struct dentry *hypfs_create_u64(struct super_block *sb, struct dentry *dir,
401 const char *name, __u64 value)
403 char *buffer;
404 char tmp[TMP_SIZE];
405 struct dentry *dentry;
407 snprintf(tmp, TMP_SIZE, "%llu\n", (unsigned long long int)value);
408 buffer = kstrdup(tmp, GFP_KERNEL);
409 if (!buffer)
410 return ERR_PTR(-ENOMEM);
411 dentry =
412 hypfs_create_file(sb, dir, name, buffer, S_IFREG | REG_FILE_MODE);
413 if (IS_ERR(dentry)) {
414 kfree(buffer);
415 return ERR_PTR(-ENOMEM);
417 hypfs_add_dentry(dentry);
418 return dentry;
421 struct dentry *hypfs_create_str(struct super_block *sb, struct dentry *dir,
422 const char *name, char *string)
424 char *buffer;
425 struct dentry *dentry;
427 buffer = kmalloc(strlen(string) + 2, GFP_KERNEL);
428 if (!buffer)
429 return ERR_PTR(-ENOMEM);
430 sprintf(buffer, "%s\n", string);
431 dentry =
432 hypfs_create_file(sb, dir, name, buffer, S_IFREG | REG_FILE_MODE);
433 if (IS_ERR(dentry)) {
434 kfree(buffer);
435 return ERR_PTR(-ENOMEM);
437 hypfs_add_dentry(dentry);
438 return dentry;
441 static const struct file_operations hypfs_file_ops = {
442 .open = hypfs_open,
443 .release = hypfs_release,
444 .read = do_sync_read,
445 .write = do_sync_write,
446 .aio_read = hypfs_aio_read,
447 .aio_write = hypfs_aio_write,
448 .llseek = no_llseek,
451 static struct file_system_type hypfs_type = {
452 .owner = THIS_MODULE,
453 .name = "s390_hypfs",
454 .mount = hypfs_mount,
455 .kill_sb = hypfs_kill_super
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,
464 static struct kobject *s390_kobj;
466 static int __init hypfs_init(void)
468 int rc;
470 rc = hypfs_dbfs_init();
471 if (rc)
472 return rc;
473 if (hypfs_diag_init()) {
474 rc = -ENODATA;
475 goto fail_dbfs_exit;
477 if (hypfs_vm_init()) {
478 rc = -ENODATA;
479 goto fail_hypfs_diag_exit;
481 s390_kobj = kobject_create_and_add("s390", hypervisor_kobj);
482 if (!s390_kobj) {
483 rc = -ENOMEM;
484 goto fail_hypfs_vm_exit;
486 rc = register_filesystem(&hypfs_type);
487 if (rc)
488 goto fail_filesystem;
489 return 0;
491 fail_filesystem:
492 kobject_put(s390_kobj);
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;
503 static void __exit hypfs_exit(void)
505 hypfs_diag_exit();
506 hypfs_vm_exit();
507 hypfs_dbfs_exit();
508 unregister_filesystem(&hypfs_type);
509 kobject_put(s390_kobj);
512 module_init(hypfs_init)
513 module_exit(hypfs_exit)
515 MODULE_LICENSE("GPL");
516 MODULE_AUTHOR("Michael Holzheu <holzheu@de.ibm.com>");
517 MODULE_DESCRIPTION("s390 Hypervisor Filesystem");