convert get_sb_single() users
[linux-3.10.git] / arch / s390 / hypfs / inode.c
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
49 struct dentry *hypfs_dbfs_dir;
50
51 static void hypfs_update_update(struct super_block *sb)
52 {
53         struct hypfs_sb_info *sb_info = sb->s_fs_info;
54         struct inode *inode = sb_info->update_file->d_inode;
55
56         sb_info->last_update = get_seconds();
57         inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
58 }
59
60 /* directory tree removal functions */
61
62 static void hypfs_add_dentry(struct dentry *dentry)
63 {
64         dentry->d_fsdata = hypfs_last_dentry;
65         hypfs_last_dentry = dentry;
66 }
67
68 static inline int hypfs_positive(struct dentry *dentry)
69 {
70         return dentry->d_inode && !d_unhashed(dentry);
71 }
72
73 static void hypfs_remove(struct dentry *dentry)
74 {
75         struct dentry *parent;
76
77         parent = dentry->d_parent;
78         if (!parent || !parent->d_inode)
79                 return;
80         mutex_lock(&parent->d_inode->i_mutex);
81         if (hypfs_positive(dentry)) {
82                 if (S_ISDIR(dentry->d_inode->i_mode))
83                         simple_rmdir(parent->d_inode, dentry);
84                 else
85                         simple_unlink(parent->d_inode, dentry);
86         }
87         d_delete(dentry);
88         dput(dentry);
89         mutex_unlock(&parent->d_inode->i_mutex);
90 }
91
92 static void hypfs_delete_tree(struct dentry *root)
93 {
94         while (hypfs_last_dentry) {
95                 struct dentry *next_dentry;
96                 next_dentry = hypfs_last_dentry->d_fsdata;
97                 hypfs_remove(hypfs_last_dentry);
98                 hypfs_last_dentry = next_dentry;
99         }
100 }
101
102 static struct inode *hypfs_make_inode(struct super_block *sb, int mode)
103 {
104         struct inode *ret = new_inode(sb);
105
106         if (ret) {
107                 struct hypfs_sb_info *hypfs_info = sb->s_fs_info;
108                 ret->i_mode = mode;
109                 ret->i_uid = hypfs_info->uid;
110                 ret->i_gid = hypfs_info->gid;
111                 ret->i_atime = ret->i_mtime = ret->i_ctime = CURRENT_TIME;
112                 if (mode & S_IFDIR)
113                         ret->i_nlink = 2;
114                 else
115                         ret->i_nlink = 1;
116         }
117         return ret;
118 }
119
120 static void hypfs_evict_inode(struct inode *inode)
121 {
122         end_writeback(inode);
123         kfree(inode->i_private);
124 }
125
126 static int hypfs_open(struct inode *inode, struct file *filp)
127 {
128         char *data = filp->f_path.dentry->d_inode->i_private;
129         struct hypfs_sb_info *fs_info;
130
131         if (filp->f_mode & FMODE_WRITE) {
132                 if (!(inode->i_mode & S_IWUGO))
133                         return -EACCES;
134         }
135         if (filp->f_mode & FMODE_READ) {
136                 if (!(inode->i_mode & S_IRUGO))
137                         return -EACCES;
138         }
139
140         fs_info = inode->i_sb->s_fs_info;
141         if(data) {
142                 mutex_lock(&fs_info->lock);
143                 filp->private_data = kstrdup(data, GFP_KERNEL);
144                 if (!filp->private_data) {
145                         mutex_unlock(&fs_info->lock);
146                         return -ENOMEM;
147                 }
148                 mutex_unlock(&fs_info->lock);
149         }
150         return nonseekable_open(inode, filp);
151 }
152
153 static ssize_t hypfs_aio_read(struct kiocb *iocb, const struct iovec *iov,
154                               unsigned long nr_segs, loff_t offset)
155 {
156         char *data;
157         ssize_t ret;
158         struct file *filp = iocb->ki_filp;
159         /* XXX: temporary */
160         char __user *buf = iov[0].iov_base;
161         size_t count = iov[0].iov_len;
162
163         if (nr_segs != 1)
164                 return -EINVAL;
165
166         data = filp->private_data;
167         ret = simple_read_from_buffer(buf, count, &offset, data, strlen(data));
168         if (ret <= 0)
169                 return ret;
170
171         iocb->ki_pos += ret;
172         file_accessed(filp);
173
174         return ret;
175 }
176 static ssize_t hypfs_aio_write(struct kiocb *iocb, const struct iovec *iov,
177                               unsigned long nr_segs, loff_t offset)
178 {
179         int rc;
180         struct super_block *sb;
181         struct hypfs_sb_info *fs_info;
182         size_t count = iov_length(iov, nr_segs);
183
184         sb = iocb->ki_filp->f_path.dentry->d_inode->i_sb;
185         fs_info = sb->s_fs_info;
186         /*
187          * Currently we only allow one update per second for two reasons:
188          * 1. diag 204 is VERY expensive
189          * 2. If several processes do updates in parallel and then read the
190          *    hypfs data, the likelihood of collisions is reduced, if we restrict
191          *    the minimum update interval. A collision occurs, if during the
192          *    data gathering of one process another process triggers an update
193          *    If the first process wants to ensure consistent data, it has
194          *    to restart data collection in this case.
195          */
196         mutex_lock(&fs_info->lock);
197         if (fs_info->last_update == get_seconds()) {
198                 rc = -EBUSY;
199                 goto out;
200         }
201         hypfs_delete_tree(sb->s_root);
202         if (MACHINE_IS_VM)
203                 rc = hypfs_vm_create_files(sb, sb->s_root);
204         else
205                 rc = hypfs_diag_create_files(sb, sb->s_root);
206         if (rc) {
207                 pr_err("Updating the hypfs tree failed\n");
208                 hypfs_delete_tree(sb->s_root);
209                 goto out;
210         }
211         hypfs_update_update(sb);
212         rc = count;
213 out:
214         mutex_unlock(&fs_info->lock);
215         return rc;
216 }
217
218 static int hypfs_release(struct inode *inode, struct file *filp)
219 {
220         kfree(filp->private_data);
221         return 0;
222 }
223
224 enum { opt_uid, opt_gid, opt_err };
225
226 static const match_table_t hypfs_tokens = {
227         {opt_uid, "uid=%u"},
228         {opt_gid, "gid=%u"},
229         {opt_err, NULL}
230 };
231
232 static int hypfs_parse_options(char *options, struct super_block *sb)
233 {
234         char *str;
235         substring_t args[MAX_OPT_ARGS];
236
237         if (!options)
238                 return 0;
239         while ((str = strsep(&options, ",")) != NULL) {
240                 int token, option;
241                 struct hypfs_sb_info *hypfs_info = sb->s_fs_info;
242
243                 if (!*str)
244                         continue;
245                 token = match_token(str, hypfs_tokens, args);
246                 switch (token) {
247                 case opt_uid:
248                         if (match_int(&args[0], &option))
249                                 return -EINVAL;
250                         hypfs_info->uid = option;
251                         break;
252                 case opt_gid:
253                         if (match_int(&args[0], &option))
254                                 return -EINVAL;
255                         hypfs_info->gid = option;
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
266 static int hypfs_show_options(struct seq_file *s, struct vfsmount *mnt)
267 {
268         struct hypfs_sb_info *hypfs_info = mnt->mnt_sb->s_fs_info;
269
270         seq_printf(s, ",uid=%u", hypfs_info->uid);
271         seq_printf(s, ",gid=%u", hypfs_info->gid);
272         return 0;
273 }
274
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_alloc_root(root_inode);
301         if (!root_dentry) {
302                 iput(root_inode);
303                 return -ENOMEM;
304         }
305         if (MACHINE_IS_VM)
306                 rc = hypfs_vm_create_files(sb, root_dentry);
307         else
308                 rc = hypfs_diag_create_files(sb, root_dentry);
309         if (rc)
310                 return rc;
311         sbi->update_file = hypfs_create_update_file(sb, root_dentry);
312         if (IS_ERR(sbi->update_file))
313                 return PTR_ERR(sbi->update_file);
314         hypfs_update_update(sb);
315         pr_info("Hypervisor filesystem mounted\n");
316         return 0;
317 }
318
319 static struct dentry *hypfs_mount(struct file_system_type *fst, int flags,
320                         const char *devname, void *data)
321 {
322         return mount_single(fst, flags, data, hypfs_fill_super);
323 }
324
325 static void hypfs_kill_super(struct super_block *sb)
326 {
327         struct hypfs_sb_info *sb_info = sb->s_fs_info;
328
329         if (sb->s_root)
330                 hypfs_delete_tree(sb->s_root);
331         if (sb_info->update_file)
332                 hypfs_remove(sb_info->update_file);
333         kfree(sb->s_fs_info);
334         sb->s_fs_info = NULL;
335         kill_litter_super(sb);
336 }
337
338 static struct dentry *hypfs_create_file(struct super_block *sb,
339                                         struct dentry *parent, const char *name,
340                                         char *data, mode_t mode)
341 {
342         struct dentry *dentry;
343         struct inode *inode;
344
345         mutex_lock(&parent->d_inode->i_mutex);
346         dentry = lookup_one_len(name, parent, strlen(name));
347         if (IS_ERR(dentry)) {
348                 dentry = ERR_PTR(-ENOMEM);
349                 goto fail;
350         }
351         inode = hypfs_make_inode(sb, mode);
352         if (!inode) {
353                 dput(dentry);
354                 dentry = ERR_PTR(-ENOMEM);
355                 goto fail;
356         }
357         if (mode & S_IFREG) {
358                 inode->i_fop = &hypfs_file_ops;
359                 if (data)
360                         inode->i_size = strlen(data);
361                 else
362                         inode->i_size = 0;
363         } else if (mode & S_IFDIR) {
364                 inode->i_op = &simple_dir_inode_operations;
365                 inode->i_fop = &simple_dir_operations;
366                 parent->d_inode->i_nlink++;
367         } else
368                 BUG();
369         inode->i_private = data;
370         d_instantiate(dentry, inode);
371         dget(dentry);
372 fail:
373         mutex_unlock(&parent->d_inode->i_mutex);
374         return dentry;
375 }
376
377 struct dentry *hypfs_mkdir(struct super_block *sb, struct dentry *parent,
378                            const char *name)
379 {
380         struct dentry *dentry;
381
382         dentry = hypfs_create_file(sb, parent, name, NULL, S_IFDIR | DIR_MODE);
383         if (IS_ERR(dentry))
384                 return dentry;
385         hypfs_add_dentry(dentry);
386         return dentry;
387 }
388
389 static struct dentry *hypfs_create_update_file(struct super_block *sb,
390                                                struct dentry *dir)
391 {
392         struct dentry *dentry;
393
394         dentry = hypfs_create_file(sb, dir, "update", NULL,
395                                    S_IFREG | UPDATE_FILE_MODE);
396         /*
397          * We do not put the update file on the 'delete' list with
398          * hypfs_add_dentry(), since it should not be removed when the tree
399          * is updated.
400          */
401         return dentry;
402 }
403
404 struct dentry *hypfs_create_u64(struct super_block *sb, struct dentry *dir,
405                                 const char *name, __u64 value)
406 {
407         char *buffer;
408         char tmp[TMP_SIZE];
409         struct dentry *dentry;
410
411         snprintf(tmp, TMP_SIZE, "%llu\n", (unsigned long long int)value);
412         buffer = kstrdup(tmp, GFP_KERNEL);
413         if (!buffer)
414                 return ERR_PTR(-ENOMEM);
415         dentry =
416             hypfs_create_file(sb, dir, name, buffer, S_IFREG | REG_FILE_MODE);
417         if (IS_ERR(dentry)) {
418                 kfree(buffer);
419                 return ERR_PTR(-ENOMEM);
420         }
421         hypfs_add_dentry(dentry);
422         return dentry;
423 }
424
425 struct dentry *hypfs_create_str(struct super_block *sb, struct dentry *dir,
426                                 const char *name, char *string)
427 {
428         char *buffer;
429         struct dentry *dentry;
430
431         buffer = kmalloc(strlen(string) + 2, GFP_KERNEL);
432         if (!buffer)
433                 return ERR_PTR(-ENOMEM);
434         sprintf(buffer, "%s\n", string);
435         dentry =
436             hypfs_create_file(sb, dir, name, buffer, S_IFREG | REG_FILE_MODE);
437         if (IS_ERR(dentry)) {
438                 kfree(buffer);
439                 return ERR_PTR(-ENOMEM);
440         }
441         hypfs_add_dentry(dentry);
442         return dentry;
443 }
444
445 static const struct file_operations hypfs_file_ops = {
446         .open           = hypfs_open,
447         .release        = hypfs_release,
448         .read           = do_sync_read,
449         .write          = do_sync_write,
450         .aio_read       = hypfs_aio_read,
451         .aio_write      = hypfs_aio_write,
452         .llseek         = no_llseek,
453 };
454
455 static struct file_system_type hypfs_type = {
456         .owner          = THIS_MODULE,
457         .name           = "s390_hypfs",
458         .mount          = hypfs_mount,
459         .kill_sb        = hypfs_kill_super
460 };
461
462 static const struct super_operations hypfs_s_ops = {
463         .statfs         = simple_statfs,
464         .evict_inode    = hypfs_evict_inode,
465         .show_options   = hypfs_show_options,
466 };
467
468 static struct kobject *s390_kobj;
469
470 static int __init hypfs_init(void)
471 {
472         int rc;
473
474         hypfs_dbfs_dir = debugfs_create_dir("s390_hypfs", NULL);
475         if (IS_ERR(hypfs_dbfs_dir))
476                 return PTR_ERR(hypfs_dbfs_dir);
477
478         if (hypfs_diag_init()) {
479                 rc = -ENODATA;
480                 goto fail_debugfs_remove;
481         }
482         if (hypfs_vm_init()) {
483                 rc = -ENODATA;
484                 goto fail_hypfs_diag_exit;
485         }
486         s390_kobj = kobject_create_and_add("s390", hypervisor_kobj);
487         if (!s390_kobj) {
488                 rc = -ENOMEM;
489                 goto fail_hypfs_vm_exit;
490         }
491         rc = register_filesystem(&hypfs_type);
492         if (rc)
493                 goto fail_filesystem;
494         return 0;
495
496 fail_filesystem:
497         kobject_put(s390_kobj);
498 fail_hypfs_vm_exit:
499         hypfs_vm_exit();
500 fail_hypfs_diag_exit:
501         hypfs_diag_exit();
502 fail_debugfs_remove:
503         debugfs_remove(hypfs_dbfs_dir);
504
505         pr_err("Initialization of hypfs failed with rc=%i\n", rc);
506         return rc;
507 }
508
509 static void __exit hypfs_exit(void)
510 {
511         hypfs_diag_exit();
512         hypfs_vm_exit();
513         debugfs_remove(hypfs_dbfs_dir);
514         unregister_filesystem(&hypfs_type);
515         kobject_put(s390_kobj);
516 }
517
518 module_init(hypfs_init)
519 module_exit(hypfs_exit)
520
521 MODULE_LICENSE("GPL");
522 MODULE_AUTHOR("Michael Holzheu <holzheu@de.ibm.com>");
523 MODULE_DESCRIPTION("s390 Hypervisor Filesystem");