Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial
[linux-2.6.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/pagemap.h>
18 #include <linux/gfp.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 static void hypfs_update_update(struct super_block *sb)
50 {
51         struct hypfs_sb_info *sb_info = sb->s_fs_info;
52         struct inode *inode = sb_info->update_file->d_inode;
53
54         sb_info->last_update = get_seconds();
55         inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
56 }
57
58 /* directory tree removal functions */
59
60 static void hypfs_add_dentry(struct dentry *dentry)
61 {
62         dentry->d_fsdata = hypfs_last_dentry;
63         hypfs_last_dentry = dentry;
64 }
65
66 static inline int hypfs_positive(struct dentry *dentry)
67 {
68         return dentry->d_inode && !d_unhashed(dentry);
69 }
70
71 static void hypfs_remove(struct dentry *dentry)
72 {
73         struct dentry *parent;
74
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);
84         }
85         d_delete(dentry);
86         dput(dentry);
87         mutex_unlock(&parent->d_inode->i_mutex);
88 }
89
90 static void hypfs_delete_tree(struct dentry *root)
91 {
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;
97         }
98 }
99
100 static struct inode *hypfs_make_inode(struct super_block *sb, int mode)
101 {
102         struct inode *ret = new_inode(sb);
103
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 (mode & S_IFDIR)
111                         ret->i_nlink = 2;
112                 else
113                         ret->i_nlink = 1;
114         }
115         return ret;
116 }
117
118 static void hypfs_drop_inode(struct inode *inode)
119 {
120         kfree(inode->i_private);
121         generic_delete_inode(inode);
122 }
123
124 static int hypfs_open(struct inode *inode, struct file *filp)
125 {
126         char *data = filp->f_path.dentry->d_inode->i_private;
127         struct hypfs_sb_info *fs_info;
128
129         if (filp->f_mode & FMODE_WRITE) {
130                 if (!(inode->i_mode & S_IWUGO))
131                         return -EACCES;
132         }
133         if (filp->f_mode & FMODE_READ) {
134                 if (!(inode->i_mode & S_IRUGO))
135                         return -EACCES;
136         }
137
138         fs_info = inode->i_sb->s_fs_info;
139         if(data) {
140                 mutex_lock(&fs_info->lock);
141                 filp->private_data = kstrdup(data, GFP_KERNEL);
142                 if (!filp->private_data) {
143                         mutex_unlock(&fs_info->lock);
144                         return -ENOMEM;
145                 }
146                 mutex_unlock(&fs_info->lock);
147         }
148         return 0;
149 }
150
151 static ssize_t hypfs_aio_read(struct kiocb *iocb, const struct iovec *iov,
152                               unsigned long nr_segs, loff_t offset)
153 {
154         char *data;
155         ssize_t ret;
156         struct file *filp = iocb->ki_filp;
157         /* XXX: temporary */
158         char __user *buf = iov[0].iov_base;
159         size_t count = iov[0].iov_len;
160
161         if (nr_segs != 1)
162                 return -EINVAL;
163
164         data = filp->private_data;
165         ret = simple_read_from_buffer(buf, count, &offset, data, strlen(data));
166         if (ret <= 0)
167                 return ret;
168
169         iocb->ki_pos += ret;
170         file_accessed(filp);
171
172         return ret;
173 }
174 static ssize_t hypfs_aio_write(struct kiocb *iocb, const struct iovec *iov,
175                               unsigned long nr_segs, loff_t offset)
176 {
177         int rc;
178         struct super_block *sb;
179         struct hypfs_sb_info *fs_info;
180         size_t count = iov_length(iov, nr_segs);
181
182         sb = iocb->ki_filp->f_path.dentry->d_inode->i_sb;
183         fs_info = sb->s_fs_info;
184         /*
185          * Currently we only allow one update per second for two reasons:
186          * 1. diag 204 is VERY expensive
187          * 2. If several processes do updates in parallel and then read the
188          *    hypfs data, the likelihood of collisions is reduced, if we restrict
189          *    the minimum update interval. A collision occurs, if during the
190          *    data gathering of one process another process triggers an update
191          *    If the first process wants to ensure consistent data, it has
192          *    to restart data collection in this case.
193          */
194         mutex_lock(&fs_info->lock);
195         if (fs_info->last_update == get_seconds()) {
196                 rc = -EBUSY;
197                 goto out;
198         }
199         hypfs_delete_tree(sb->s_root);
200         if (MACHINE_IS_VM)
201                 rc = hypfs_vm_create_files(sb, sb->s_root);
202         else
203                 rc = hypfs_diag_create_files(sb, sb->s_root);
204         if (rc) {
205                 pr_err("Updating the hypfs tree failed\n");
206                 hypfs_delete_tree(sb->s_root);
207                 goto out;
208         }
209         hypfs_update_update(sb);
210         rc = count;
211 out:
212         mutex_unlock(&fs_info->lock);
213         return rc;
214 }
215
216 static int hypfs_release(struct inode *inode, struct file *filp)
217 {
218         kfree(filp->private_data);
219         return 0;
220 }
221
222 enum { opt_uid, opt_gid, opt_err };
223
224 static const match_table_t hypfs_tokens = {
225         {opt_uid, "uid=%u"},
226         {opt_gid, "gid=%u"},
227         {opt_err, NULL}
228 };
229
230 static int hypfs_parse_options(char *options, struct super_block *sb)
231 {
232         char *str;
233         substring_t args[MAX_OPT_ARGS];
234
235         if (!options)
236                 return 0;
237         while ((str = strsep(&options, ",")) != NULL) {
238                 int token, option;
239                 struct hypfs_sb_info *hypfs_info = sb->s_fs_info;
240
241                 if (!*str)
242                         continue;
243                 token = match_token(str, hypfs_tokens, args);
244                 switch (token) {
245                 case opt_uid:
246                         if (match_int(&args[0], &option))
247                                 return -EINVAL;
248                         hypfs_info->uid = option;
249                         break;
250                 case opt_gid:
251                         if (match_int(&args[0], &option))
252                                 return -EINVAL;
253                         hypfs_info->gid = option;
254                         break;
255                 case opt_err:
256                 default:
257                         pr_err("%s is not a valid mount option\n", str);
258                         return -EINVAL;
259                 }
260         }
261         return 0;
262 }
263
264 static int hypfs_show_options(struct seq_file *s, struct vfsmount *mnt)
265 {
266         struct hypfs_sb_info *hypfs_info = mnt->mnt_sb->s_fs_info;
267
268         seq_printf(s, ",uid=%u", hypfs_info->uid);
269         seq_printf(s, ",gid=%u", hypfs_info->gid);
270         return 0;
271 }
272
273 static int hypfs_fill_super(struct super_block *sb, void *data, int silent)
274 {
275         struct inode *root_inode;
276         struct dentry *root_dentry;
277         int rc = 0;
278         struct hypfs_sb_info *sbi;
279
280         sbi = kzalloc(sizeof(struct hypfs_sb_info), GFP_KERNEL);
281         if (!sbi)
282                 return -ENOMEM;
283         mutex_init(&sbi->lock);
284         sbi->uid = current_uid();
285         sbi->gid = current_gid();
286         sb->s_fs_info = sbi;
287         sb->s_blocksize = PAGE_CACHE_SIZE;
288         sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
289         sb->s_magic = HYPFS_MAGIC;
290         sb->s_op = &hypfs_s_ops;
291         if (hypfs_parse_options(data, sb)) {
292                 rc = -EINVAL;
293                 goto err_alloc;
294         }
295         root_inode = hypfs_make_inode(sb, S_IFDIR | 0755);
296         if (!root_inode) {
297                 rc = -ENOMEM;
298                 goto err_alloc;
299         }
300         root_inode->i_op = &simple_dir_inode_operations;
301         root_inode->i_fop = &simple_dir_operations;
302         root_dentry = d_alloc_root(root_inode);
303         if (!root_dentry) {
304                 iput(root_inode);
305                 rc = -ENOMEM;
306                 goto err_alloc;
307         }
308         if (MACHINE_IS_VM)
309                 rc = hypfs_vm_create_files(sb, root_dentry);
310         else
311                 rc = hypfs_diag_create_files(sb, root_dentry);
312         if (rc)
313                 goto err_tree;
314         sbi->update_file = hypfs_create_update_file(sb, root_dentry);
315         if (IS_ERR(sbi->update_file)) {
316                 rc = PTR_ERR(sbi->update_file);
317                 goto err_tree;
318         }
319         hypfs_update_update(sb);
320         sb->s_root = root_dentry;
321         pr_info("Hypervisor filesystem mounted\n");
322         return 0;
323
324 err_tree:
325         hypfs_delete_tree(root_dentry);
326         d_genocide(root_dentry);
327         dput(root_dentry);
328 err_alloc:
329         kfree(sbi);
330         return rc;
331 }
332
333 static int hypfs_get_super(struct file_system_type *fst, int flags,
334                         const char *devname, void *data, struct vfsmount *mnt)
335 {
336         return get_sb_single(fst, flags, data, hypfs_fill_super, mnt);
337 }
338
339 static void hypfs_kill_super(struct super_block *sb)
340 {
341         struct hypfs_sb_info *sb_info = sb->s_fs_info;
342
343         if (sb->s_root) {
344                 hypfs_delete_tree(sb->s_root);
345                 hypfs_remove(sb_info->update_file);
346                 kfree(sb->s_fs_info);
347                 sb->s_fs_info = NULL;
348         }
349         kill_litter_super(sb);
350 }
351
352 static struct dentry *hypfs_create_file(struct super_block *sb,
353                                         struct dentry *parent, const char *name,
354                                         char *data, mode_t mode)
355 {
356         struct dentry *dentry;
357         struct inode *inode;
358
359         mutex_lock(&parent->d_inode->i_mutex);
360         dentry = lookup_one_len(name, parent, strlen(name));
361         if (IS_ERR(dentry)) {
362                 dentry = ERR_PTR(-ENOMEM);
363                 goto fail;
364         }
365         inode = hypfs_make_inode(sb, mode);
366         if (!inode) {
367                 dput(dentry);
368                 dentry = ERR_PTR(-ENOMEM);
369                 goto fail;
370         }
371         if (mode & S_IFREG) {
372                 inode->i_fop = &hypfs_file_ops;
373                 if (data)
374                         inode->i_size = strlen(data);
375                 else
376                         inode->i_size = 0;
377         } else if (mode & S_IFDIR) {
378                 inode->i_op = &simple_dir_inode_operations;
379                 inode->i_fop = &simple_dir_operations;
380                 parent->d_inode->i_nlink++;
381         } else
382                 BUG();
383         inode->i_private = data;
384         d_instantiate(dentry, inode);
385         dget(dentry);
386 fail:
387         mutex_unlock(&parent->d_inode->i_mutex);
388         return dentry;
389 }
390
391 struct dentry *hypfs_mkdir(struct super_block *sb, struct dentry *parent,
392                            const char *name)
393 {
394         struct dentry *dentry;
395
396         dentry = hypfs_create_file(sb, parent, name, NULL, S_IFDIR | DIR_MODE);
397         if (IS_ERR(dentry))
398                 return dentry;
399         hypfs_add_dentry(dentry);
400         return dentry;
401 }
402
403 static struct dentry *hypfs_create_update_file(struct super_block *sb,
404                                                struct dentry *dir)
405 {
406         struct dentry *dentry;
407
408         dentry = hypfs_create_file(sb, dir, "update", NULL,
409                                    S_IFREG | UPDATE_FILE_MODE);
410         /*
411          * We do not put the update file on the 'delete' list with
412          * hypfs_add_dentry(), since it should not be removed when the tree
413          * is updated.
414          */
415         return dentry;
416 }
417
418 struct dentry *hypfs_create_u64(struct super_block *sb, struct dentry *dir,
419                                 const char *name, __u64 value)
420 {
421         char *buffer;
422         char tmp[TMP_SIZE];
423         struct dentry *dentry;
424
425         snprintf(tmp, TMP_SIZE, "%llu\n", (unsigned long long int)value);
426         buffer = kstrdup(tmp, GFP_KERNEL);
427         if (!buffer)
428                 return ERR_PTR(-ENOMEM);
429         dentry =
430             hypfs_create_file(sb, dir, name, buffer, S_IFREG | REG_FILE_MODE);
431         if (IS_ERR(dentry)) {
432                 kfree(buffer);
433                 return ERR_PTR(-ENOMEM);
434         }
435         hypfs_add_dentry(dentry);
436         return dentry;
437 }
438
439 struct dentry *hypfs_create_str(struct super_block *sb, struct dentry *dir,
440                                 const char *name, char *string)
441 {
442         char *buffer;
443         struct dentry *dentry;
444
445         buffer = kmalloc(strlen(string) + 2, GFP_KERNEL);
446         if (!buffer)
447                 return ERR_PTR(-ENOMEM);
448         sprintf(buffer, "%s\n", string);
449         dentry =
450             hypfs_create_file(sb, dir, name, buffer, S_IFREG | REG_FILE_MODE);
451         if (IS_ERR(dentry)) {
452                 kfree(buffer);
453                 return ERR_PTR(-ENOMEM);
454         }
455         hypfs_add_dentry(dentry);
456         return dentry;
457 }
458
459 static const struct file_operations hypfs_file_ops = {
460         .open           = hypfs_open,
461         .release        = hypfs_release,
462         .read           = do_sync_read,
463         .write          = do_sync_write,
464         .aio_read       = hypfs_aio_read,
465         .aio_write      = hypfs_aio_write,
466 };
467
468 static struct file_system_type hypfs_type = {
469         .owner          = THIS_MODULE,
470         .name           = "s390_hypfs",
471         .get_sb         = hypfs_get_super,
472         .kill_sb        = hypfs_kill_super
473 };
474
475 static const struct super_operations hypfs_s_ops = {
476         .statfs         = simple_statfs,
477         .drop_inode     = hypfs_drop_inode,
478         .show_options   = hypfs_show_options,
479 };
480
481 static struct kobject *s390_kobj;
482
483 static int __init hypfs_init(void)
484 {
485         int rc;
486
487         if (MACHINE_IS_VM) {
488                 if (hypfs_vm_init())
489                         /* no diag 2fc, just exit */
490                         return -ENODATA;
491         } else {
492                 if (hypfs_diag_init()) {
493                         rc = -ENODATA;
494                         goto fail_diag;
495                 }
496         }
497         s390_kobj = kobject_create_and_add("s390", hypervisor_kobj);
498         if (!s390_kobj) {
499                 rc = -ENOMEM;
500                 goto fail_sysfs;
501         }
502         rc = register_filesystem(&hypfs_type);
503         if (rc)
504                 goto fail_filesystem;
505         return 0;
506
507 fail_filesystem:
508         kobject_put(s390_kobj);
509 fail_sysfs:
510         if (!MACHINE_IS_VM)
511                 hypfs_diag_exit();
512 fail_diag:
513         pr_err("Initialization of hypfs failed with rc=%i\n", rc);
514         return rc;
515 }
516
517 static void __exit hypfs_exit(void)
518 {
519         if (!MACHINE_IS_VM)
520                 hypfs_diag_exit();
521         unregister_filesystem(&hypfs_type);
522         kobject_put(s390_kobj);
523 }
524
525 module_init(hypfs_init)
526 module_exit(hypfs_exit)
527
528 MODULE_LICENSE("GPL");
529 MODULE_AUTHOR("Michael Holzheu <holzheu@de.ibm.com>");
530 MODULE_DESCRIPTION("s390 Hypervisor Filesystem");