include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit...
[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 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                 return -EINVAL;
293         root_inode = hypfs_make_inode(sb, S_IFDIR | 0755);
294         if (!root_inode)
295                 return -ENOMEM;
296         root_inode->i_op = &simple_dir_inode_operations;
297         root_inode->i_fop = &simple_dir_operations;
298         sb->s_root = root_dentry = d_alloc_root(root_inode);
299         if (!root_dentry) {
300                 iput(root_inode);
301                 return -ENOMEM;
302         }
303         if (MACHINE_IS_VM)
304                 rc = hypfs_vm_create_files(sb, root_dentry);
305         else
306                 rc = hypfs_diag_create_files(sb, root_dentry);
307         if (rc)
308                 return rc;
309         sbi->update_file = hypfs_create_update_file(sb, 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
317 static int hypfs_get_super(struct file_system_type *fst, int flags,
318                         const char *devname, void *data, struct vfsmount *mnt)
319 {
320         return get_sb_single(fst, flags, data, hypfs_fill_super, mnt);
321 }
322
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
336 static struct dentry *hypfs_create_file(struct super_block *sb,
337                                         struct dentry *parent, const char *name,
338                                         char *data, mode_t mode)
339 {
340         struct dentry *dentry;
341         struct inode *inode;
342
343         mutex_lock(&parent->d_inode->i_mutex);
344         dentry = lookup_one_len(name, parent, strlen(name));
345         if (IS_ERR(dentry)) {
346                 dentry = ERR_PTR(-ENOMEM);
347                 goto fail;
348         }
349         inode = hypfs_make_inode(sb, mode);
350         if (!inode) {
351                 dput(dentry);
352                 dentry = ERR_PTR(-ENOMEM);
353                 goto fail;
354         }
355         if (mode & S_IFREG) {
356                 inode->i_fop = &hypfs_file_ops;
357                 if (data)
358                         inode->i_size = strlen(data);
359                 else
360                         inode->i_size = 0;
361         } else if (mode & S_IFDIR) {
362                 inode->i_op = &simple_dir_inode_operations;
363                 inode->i_fop = &simple_dir_operations;
364                 parent->d_inode->i_nlink++;
365         } else
366                 BUG();
367         inode->i_private = data;
368         d_instantiate(dentry, inode);
369         dget(dentry);
370 fail:
371         mutex_unlock(&parent->d_inode->i_mutex);
372         return dentry;
373 }
374
375 struct dentry *hypfs_mkdir(struct super_block *sb, struct dentry *parent,
376                            const char *name)
377 {
378         struct dentry *dentry;
379
380         dentry = hypfs_create_file(sb, parent, name, NULL, S_IFDIR | DIR_MODE);
381         if (IS_ERR(dentry))
382                 return dentry;
383         hypfs_add_dentry(dentry);
384         return dentry;
385 }
386
387 static struct dentry *hypfs_create_update_file(struct super_block *sb,
388                                                struct dentry *dir)
389 {
390         struct dentry *dentry;
391
392         dentry = hypfs_create_file(sb, dir, "update", NULL,
393                                    S_IFREG | UPDATE_FILE_MODE);
394         /*
395          * We do not put the update file on the 'delete' list with
396          * hypfs_add_dentry(), since it should not be removed when the tree
397          * is updated.
398          */
399         return dentry;
400 }
401
402 struct dentry *hypfs_create_u64(struct super_block *sb, struct dentry *dir,
403                                 const char *name, __u64 value)
404 {
405         char *buffer;
406         char tmp[TMP_SIZE];
407         struct dentry *dentry;
408
409         snprintf(tmp, TMP_SIZE, "%llu\n", (unsigned long long int)value);
410         buffer = kstrdup(tmp, GFP_KERNEL);
411         if (!buffer)
412                 return ERR_PTR(-ENOMEM);
413         dentry =
414             hypfs_create_file(sb, dir, name, buffer, S_IFREG | REG_FILE_MODE);
415         if (IS_ERR(dentry)) {
416                 kfree(buffer);
417                 return ERR_PTR(-ENOMEM);
418         }
419         hypfs_add_dentry(dentry);
420         return dentry;
421 }
422
423 struct dentry *hypfs_create_str(struct super_block *sb, struct dentry *dir,
424                                 const char *name, char *string)
425 {
426         char *buffer;
427         struct dentry *dentry;
428
429         buffer = kmalloc(strlen(string) + 2, GFP_KERNEL);
430         if (!buffer)
431                 return ERR_PTR(-ENOMEM);
432         sprintf(buffer, "%s\n", string);
433         dentry =
434             hypfs_create_file(sb, dir, name, buffer, S_IFREG | REG_FILE_MODE);
435         if (IS_ERR(dentry)) {
436                 kfree(buffer);
437                 return ERR_PTR(-ENOMEM);
438         }
439         hypfs_add_dentry(dentry);
440         return dentry;
441 }
442
443 static const struct file_operations hypfs_file_ops = {
444         .open           = hypfs_open,
445         .release        = hypfs_release,
446         .read           = do_sync_read,
447         .write          = do_sync_write,
448         .aio_read       = hypfs_aio_read,
449         .aio_write      = hypfs_aio_write,
450 };
451
452 static struct file_system_type hypfs_type = {
453         .owner          = THIS_MODULE,
454         .name           = "s390_hypfs",
455         .get_sb         = hypfs_get_super,
456         .kill_sb        = hypfs_kill_super
457 };
458
459 static const struct super_operations hypfs_s_ops = {
460         .statfs         = simple_statfs,
461         .drop_inode     = hypfs_drop_inode,
462         .show_options   = hypfs_show_options,
463 };
464
465 static struct kobject *s390_kobj;
466
467 static int __init hypfs_init(void)
468 {
469         int rc;
470
471         if (MACHINE_IS_VM) {
472                 if (hypfs_vm_init())
473                         /* no diag 2fc, just exit */
474                         return -ENODATA;
475         } else {
476                 if (hypfs_diag_init()) {
477                         rc = -ENODATA;
478                         goto fail_diag;
479                 }
480         }
481         s390_kobj = kobject_create_and_add("s390", hypervisor_kobj);
482         if (!s390_kobj) {
483                 rc = -ENOMEM;
484                 goto fail_sysfs;
485         }
486         rc = register_filesystem(&hypfs_type);
487         if (rc)
488                 goto fail_filesystem;
489         return 0;
490
491 fail_filesystem:
492         kobject_put(s390_kobj);
493 fail_sysfs:
494         if (!MACHINE_IS_VM)
495                 hypfs_diag_exit();
496 fail_diag:
497         pr_err("Initialization of hypfs failed with rc=%i\n", rc);
498         return rc;
499 }
500
501 static void __exit hypfs_exit(void)
502 {
503         if (!MACHINE_IS_VM)
504                 hypfs_diag_exit();
505         unregister_filesystem(&hypfs_type);
506         kobject_put(s390_kobj);
507 }
508
509 module_init(hypfs_init)
510 module_exit(hypfs_exit)
511
512 MODULE_LICENSE("GPL");
513 MODULE_AUTHOR("Michael Holzheu <holzheu@de.ibm.com>");
514 MODULE_DESCRIPTION("s390 Hypervisor Filesystem");