]> nv-tegra.nvidia Code Review - linux-2.6.git/blob - arch/s390/hypfs/inode.c
Merge branch 'for-linus' of git://git390.osdl.marist.edu/pub/scm/linux-2.6
[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 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_blocks = 0;
110                 ret->i_atime = ret->i_mtime = ret->i_ctime = CURRENT_TIME;
111                 if (mode & S_IFDIR)
112                         ret->i_nlink = 2;
113                 else
114                         ret->i_nlink = 1;
115         }
116         return ret;
117 }
118
119 static void hypfs_drop_inode(struct inode *inode)
120 {
121         kfree(inode->i_private);
122         generic_delete_inode(inode);
123 }
124
125 static int hypfs_open(struct inode *inode, struct file *filp)
126 {
127         char *data = filp->f_path.dentry->d_inode->i_private;
128         struct hypfs_sb_info *fs_info;
129
130         if (filp->f_mode & FMODE_WRITE) {
131                 if (!(inode->i_mode & S_IWUGO))
132                         return -EACCES;
133         }
134         if (filp->f_mode & FMODE_READ) {
135                 if (!(inode->i_mode & S_IRUGO))
136                         return -EACCES;
137         }
138
139         fs_info = inode->i_sb->s_fs_info;
140         if(data) {
141                 mutex_lock(&fs_info->lock);
142                 filp->private_data = kstrdup(data, GFP_KERNEL);
143                 if (!filp->private_data) {
144                         mutex_unlock(&fs_info->lock);
145                         return -ENOMEM;
146                 }
147                 mutex_unlock(&fs_info->lock);
148         }
149         return 0;
150 }
151
152 static ssize_t hypfs_aio_read(struct kiocb *iocb, const struct iovec *iov,
153                               unsigned long nr_segs, loff_t offset)
154 {
155         char *data;
156         ssize_t ret;
157         struct file *filp = iocb->ki_filp;
158         /* XXX: temporary */
159         char __user *buf = iov[0].iov_base;
160         size_t count = iov[0].iov_len;
161
162         if (nr_segs != 1)
163                 return -EINVAL;
164
165         data = filp->private_data;
166         ret = simple_read_from_buffer(buf, count, &offset, data, strlen(data));
167         if (ret <= 0)
168                 return ret;
169
170         iocb->ki_pos += ret;
171         file_accessed(filp);
172
173         return ret;
174 }
175 static ssize_t hypfs_aio_write(struct kiocb *iocb, const struct iovec *iov,
176                               unsigned long nr_segs, loff_t offset)
177 {
178         int rc;
179         struct super_block *sb;
180         struct hypfs_sb_info *fs_info;
181         size_t count = iov_length(iov, nr_segs);
182
183         sb = iocb->ki_filp->f_path.dentry->d_inode->i_sb;
184         fs_info = sb->s_fs_info;
185         /*
186          * Currently we only allow one update per second for two reasons:
187          * 1. diag 204 is VERY expensive
188          * 2. If several processes do updates in parallel and then read the
189          *    hypfs data, the likelihood of collisions is reduced, if we restrict
190          *    the minimum update interval. A collision occurs, if during the
191          *    data gathering of one process another process triggers an update
192          *    If the first process wants to ensure consistent data, it has
193          *    to restart data collection in this case.
194          */
195         mutex_lock(&fs_info->lock);
196         if (fs_info->last_update == get_seconds()) {
197                 rc = -EBUSY;
198                 goto out;
199         }
200         hypfs_delete_tree(sb->s_root);
201         if (MACHINE_IS_VM)
202                 rc = hypfs_vm_create_files(sb, sb->s_root);
203         else
204                 rc = hypfs_diag_create_files(sb, sb->s_root);
205         if (rc) {
206                 pr_err("Updating the hypfs tree failed\n");
207                 hypfs_delete_tree(sb->s_root);
208                 goto out;
209         }
210         hypfs_update_update(sb);
211         rc = count;
212 out:
213         mutex_unlock(&fs_info->lock);
214         return rc;
215 }
216
217 static int hypfs_release(struct inode *inode, struct file *filp)
218 {
219         kfree(filp->private_data);
220         return 0;
221 }
222
223 enum { opt_uid, opt_gid, opt_err };
224
225 static const match_table_t hypfs_tokens = {
226         {opt_uid, "uid=%u"},
227         {opt_gid, "gid=%u"},
228         {opt_err, NULL}
229 };
230
231 static int hypfs_parse_options(char *options, struct super_block *sb)
232 {
233         char *str;
234         substring_t args[MAX_OPT_ARGS];
235
236         if (!options)
237                 return 0;
238         while ((str = strsep(&options, ",")) != NULL) {
239                 int token, option;
240                 struct hypfs_sb_info *hypfs_info = sb->s_fs_info;
241
242                 if (!*str)
243                         continue;
244                 token = match_token(str, hypfs_tokens, args);
245                 switch (token) {
246                 case opt_uid:
247                         if (match_int(&args[0], &option))
248                                 return -EINVAL;
249                         hypfs_info->uid = option;
250                         break;
251                 case opt_gid:
252                         if (match_int(&args[0], &option))
253                                 return -EINVAL;
254                         hypfs_info->gid = option;
255                         break;
256                 case opt_err:
257                 default:
258                         pr_err("%s is not a valid mount option\n", str);
259                         return -EINVAL;
260                 }
261         }
262         return 0;
263 }
264
265 static int hypfs_show_options(struct seq_file *s, struct vfsmount *mnt)
266 {
267         struct hypfs_sb_info *hypfs_info = mnt->mnt_sb->s_fs_info;
268
269         seq_printf(s, ",uid=%u", hypfs_info->uid);
270         seq_printf(s, ",gid=%u", hypfs_info->gid);
271         return 0;
272 }
273
274 static int hypfs_fill_super(struct super_block *sb, void *data, int silent)
275 {
276         struct inode *root_inode;
277         struct dentry *root_dentry;
278         int rc = 0;
279         struct hypfs_sb_info *sbi;
280
281         sbi = kzalloc(sizeof(struct hypfs_sb_info), GFP_KERNEL);
282         if (!sbi)
283                 return -ENOMEM;
284         mutex_init(&sbi->lock);
285         sbi->uid = current_uid();
286         sbi->gid = current_gid();
287         sb->s_fs_info = sbi;
288         sb->s_blocksize = PAGE_CACHE_SIZE;
289         sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
290         sb->s_magic = HYPFS_MAGIC;
291         sb->s_op = &hypfs_s_ops;
292         if (hypfs_parse_options(data, sb)) {
293                 rc = -EINVAL;
294                 goto err_alloc;
295         }
296         root_inode = hypfs_make_inode(sb, S_IFDIR | 0755);
297         if (!root_inode) {
298                 rc = -ENOMEM;
299                 goto err_alloc;
300         }
301         root_inode->i_op = &simple_dir_inode_operations;
302         root_inode->i_fop = &simple_dir_operations;
303         root_dentry = d_alloc_root(root_inode);
304         if (!root_dentry) {
305                 iput(root_inode);
306                 rc = -ENOMEM;
307                 goto err_alloc;
308         }
309         if (MACHINE_IS_VM)
310                 rc = hypfs_vm_create_files(sb, root_dentry);
311         else
312                 rc = hypfs_diag_create_files(sb, root_dentry);
313         if (rc)
314                 goto err_tree;
315         sbi->update_file = hypfs_create_update_file(sb, root_dentry);
316         if (IS_ERR(sbi->update_file)) {
317                 rc = PTR_ERR(sbi->update_file);
318                 goto err_tree;
319         }
320         hypfs_update_update(sb);
321         sb->s_root = root_dentry;
322         pr_info("Hypervisor filesystem mounted\n");
323         return 0;
324
325 err_tree:
326         hypfs_delete_tree(root_dentry);
327         d_genocide(root_dentry);
328         dput(root_dentry);
329 err_alloc:
330         kfree(sbi);
331         return rc;
332 }
333
334 static int hypfs_get_super(struct file_system_type *fst, int flags,
335                         const char *devname, void *data, struct vfsmount *mnt)
336 {
337         return get_sb_single(fst, flags, data, hypfs_fill_super, mnt);
338 }
339
340 static void hypfs_kill_super(struct super_block *sb)
341 {
342         struct hypfs_sb_info *sb_info = sb->s_fs_info;
343
344         if (sb->s_root) {
345                 hypfs_delete_tree(sb->s_root);
346                 hypfs_remove(sb_info->update_file);
347                 kfree(sb->s_fs_info);
348                 sb->s_fs_info = NULL;
349         }
350         kill_litter_super(sb);
351 }
352
353 static struct dentry *hypfs_create_file(struct super_block *sb,
354                                         struct dentry *parent, const char *name,
355                                         char *data, mode_t mode)
356 {
357         struct dentry *dentry;
358         struct inode *inode;
359         struct qstr qname;
360
361         qname.name = name;
362         qname.len = strlen(name);
363         qname.hash = full_name_hash(name, qname.len);
364         mutex_lock(&parent->d_inode->i_mutex);
365         dentry = lookup_one_len(name, parent, strlen(name));
366         if (IS_ERR(dentry)) {
367                 dentry = ERR_PTR(-ENOMEM);
368                 goto fail;
369         }
370         inode = hypfs_make_inode(sb, mode);
371         if (!inode) {
372                 dput(dentry);
373                 dentry = ERR_PTR(-ENOMEM);
374                 goto fail;
375         }
376         if (mode & S_IFREG) {
377                 inode->i_fop = &hypfs_file_ops;
378                 if (data)
379                         inode->i_size = strlen(data);
380                 else
381                         inode->i_size = 0;
382         } else if (mode & S_IFDIR) {
383                 inode->i_op = &simple_dir_inode_operations;
384                 inode->i_fop = &simple_dir_operations;
385                 parent->d_inode->i_nlink++;
386         } else
387                 BUG();
388         inode->i_private = data;
389         d_instantiate(dentry, inode);
390         dget(dentry);
391 fail:
392         mutex_unlock(&parent->d_inode->i_mutex);
393         return dentry;
394 }
395
396 struct dentry *hypfs_mkdir(struct super_block *sb, struct dentry *parent,
397                            const char *name)
398 {
399         struct dentry *dentry;
400
401         dentry = hypfs_create_file(sb, parent, name, NULL, S_IFDIR | DIR_MODE);
402         if (IS_ERR(dentry))
403                 return dentry;
404         hypfs_add_dentry(dentry);
405         return dentry;
406 }
407
408 static struct dentry *hypfs_create_update_file(struct super_block *sb,
409                                                struct dentry *dir)
410 {
411         struct dentry *dentry;
412
413         dentry = hypfs_create_file(sb, dir, "update", NULL,
414                                    S_IFREG | UPDATE_FILE_MODE);
415         /*
416          * We do not put the update file on the 'delete' list with
417          * hypfs_add_dentry(), since it should not be removed when the tree
418          * is updated.
419          */
420         return dentry;
421 }
422
423 struct dentry *hypfs_create_u64(struct super_block *sb, struct dentry *dir,
424                                 const char *name, __u64 value)
425 {
426         char *buffer;
427         char tmp[TMP_SIZE];
428         struct dentry *dentry;
429
430         snprintf(tmp, TMP_SIZE, "%lld\n", (unsigned long long int)value);
431         buffer = kstrdup(tmp, GFP_KERNEL);
432         if (!buffer)
433                 return ERR_PTR(-ENOMEM);
434         dentry =
435             hypfs_create_file(sb, dir, name, buffer, S_IFREG | REG_FILE_MODE);
436         if (IS_ERR(dentry)) {
437                 kfree(buffer);
438                 return ERR_PTR(-ENOMEM);
439         }
440         hypfs_add_dentry(dentry);
441         return dentry;
442 }
443
444 struct dentry *hypfs_create_str(struct super_block *sb, struct dentry *dir,
445                                 const char *name, char *string)
446 {
447         char *buffer;
448         struct dentry *dentry;
449
450         buffer = kmalloc(strlen(string) + 2, GFP_KERNEL);
451         if (!buffer)
452                 return ERR_PTR(-ENOMEM);
453         sprintf(buffer, "%s\n", string);
454         dentry =
455             hypfs_create_file(sb, dir, name, buffer, S_IFREG | REG_FILE_MODE);
456         if (IS_ERR(dentry)) {
457                 kfree(buffer);
458                 return ERR_PTR(-ENOMEM);
459         }
460         hypfs_add_dentry(dentry);
461         return dentry;
462 }
463
464 static const struct file_operations hypfs_file_ops = {
465         .open           = hypfs_open,
466         .release        = hypfs_release,
467         .read           = do_sync_read,
468         .write          = do_sync_write,
469         .aio_read       = hypfs_aio_read,
470         .aio_write      = hypfs_aio_write,
471 };
472
473 static struct file_system_type hypfs_type = {
474         .owner          = THIS_MODULE,
475         .name           = "s390_hypfs",
476         .get_sb         = hypfs_get_super,
477         .kill_sb        = hypfs_kill_super
478 };
479
480 static struct super_operations hypfs_s_ops = {
481         .statfs         = simple_statfs,
482         .drop_inode     = hypfs_drop_inode,
483         .show_options   = hypfs_show_options,
484 };
485
486 static struct kobject *s390_kobj;
487
488 static int __init hypfs_init(void)
489 {
490         int rc;
491
492         if (MACHINE_IS_VM) {
493                 if (hypfs_vm_init())
494                         /* no diag 2fc, just exit */
495                         return -ENODATA;
496         } else {
497                 if (hypfs_diag_init()) {
498                         rc = -ENODATA;
499                         goto fail_diag;
500                 }
501         }
502         s390_kobj = kobject_create_and_add("s390", hypervisor_kobj);
503         if (!s390_kobj) {
504                 rc = -ENOMEM;;
505                 goto fail_sysfs;
506         }
507         rc = register_filesystem(&hypfs_type);
508         if (rc)
509                 goto fail_filesystem;
510         return 0;
511
512 fail_filesystem:
513         kobject_put(s390_kobj);
514 fail_sysfs:
515         if (!MACHINE_IS_VM)
516                 hypfs_diag_exit();
517 fail_diag:
518         pr_err("Initialization of hypfs failed with rc=%i\n", rc);
519         return rc;
520 }
521
522 static void __exit hypfs_exit(void)
523 {
524         if (!MACHINE_IS_VM)
525                 hypfs_diag_exit();
526         unregister_filesystem(&hypfs_type);
527         kobject_put(s390_kobj);
528 }
529
530 module_init(hypfs_init)
531 module_exit(hypfs_exit)
532
533 MODULE_LICENSE("GPL");
534 MODULE_AUTHOR("Michael Holzheu <holzheu@de.ibm.com>");
535 MODULE_DESCRIPTION("s390 Hypervisor Filesystem");