blob: 7d487047dbb8814ea1d5f0a01c9e30c630d9a322 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * fs/libfs.c
3 * Library for filesystems writers.
4 */
5
6#include <linux/module.h>
7#include <linux/pagemap.h>
8#include <linux/mount.h>
9#include <linux/vfs.h>
Ingo Molnar7cf34c72006-03-23 03:00:36 -080010#include <linux/mutex.h>
11
Linus Torvalds1da177e2005-04-16 15:20:36 -070012#include <asm/uaccess.h>
13
14int simple_getattr(struct vfsmount *mnt, struct dentry *dentry,
15 struct kstat *stat)
16{
17 struct inode *inode = dentry->d_inode;
18 generic_fillattr(inode, stat);
19 stat->blocks = inode->i_mapping->nrpages << (PAGE_CACHE_SHIFT - 9);
20 return 0;
21}
22
David Howells726c3342006-06-23 02:02:58 -070023int simple_statfs(struct dentry *dentry, struct kstatfs *buf)
Linus Torvalds1da177e2005-04-16 15:20:36 -070024{
David Howells726c3342006-06-23 02:02:58 -070025 buf->f_type = dentry->d_sb->s_magic;
Linus Torvalds1da177e2005-04-16 15:20:36 -070026 buf->f_bsize = PAGE_CACHE_SIZE;
27 buf->f_namelen = NAME_MAX;
28 return 0;
29}
30
31/*
32 * Retaining negative dentries for an in-memory filesystem just wastes
33 * memory and lookup time: arrange for them to be deleted immediately.
34 */
35static int simple_delete_dentry(struct dentry *dentry)
36{
37 return 1;
38}
39
40/*
41 * Lookup the data. This is trivial - if the dentry didn't already
42 * exist, we know it is negative. Set d_op to delete negative dentries.
43 */
44struct dentry *simple_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd)
45{
46 static struct dentry_operations simple_dentry_operations = {
47 .d_delete = simple_delete_dentry,
48 };
49
50 if (dentry->d_name.len > NAME_MAX)
51 return ERR_PTR(-ENAMETOOLONG);
52 dentry->d_op = &simple_dentry_operations;
53 d_add(dentry, NULL);
54 return NULL;
55}
56
57int simple_sync_file(struct file * file, struct dentry *dentry, int datasync)
58{
59 return 0;
60}
61
62int dcache_dir_open(struct inode *inode, struct file *file)
63{
64 static struct qstr cursor_name = {.len = 1, .name = "."};
65
Josef "Jeff" Sipek0f7fc9e2006-12-08 02:36:35 -080066 file->private_data = d_alloc(file->f_path.dentry, &cursor_name);
Linus Torvalds1da177e2005-04-16 15:20:36 -070067
68 return file->private_data ? 0 : -ENOMEM;
69}
70
71int dcache_dir_close(struct inode *inode, struct file *file)
72{
73 dput(file->private_data);
74 return 0;
75}
76
77loff_t dcache_dir_lseek(struct file *file, loff_t offset, int origin)
78{
Josef "Jeff" Sipek0f7fc9e2006-12-08 02:36:35 -080079 mutex_lock(&file->f_path.dentry->d_inode->i_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -070080 switch (origin) {
81 case 1:
82 offset += file->f_pos;
83 case 0:
84 if (offset >= 0)
85 break;
86 default:
Josef "Jeff" Sipek0f7fc9e2006-12-08 02:36:35 -080087 mutex_unlock(&file->f_path.dentry->d_inode->i_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -070088 return -EINVAL;
89 }
90 if (offset != file->f_pos) {
91 file->f_pos = offset;
92 if (file->f_pos >= 2) {
93 struct list_head *p;
94 struct dentry *cursor = file->private_data;
95 loff_t n = file->f_pos - 2;
96
97 spin_lock(&dcache_lock);
Eric Dumazet5160ee62006-01-08 01:03:32 -080098 list_del(&cursor->d_u.d_child);
Josef "Jeff" Sipek0f7fc9e2006-12-08 02:36:35 -080099 p = file->f_path.dentry->d_subdirs.next;
100 while (n && p != &file->f_path.dentry->d_subdirs) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700101 struct dentry *next;
Eric Dumazet5160ee62006-01-08 01:03:32 -0800102 next = list_entry(p, struct dentry, d_u.d_child);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700103 if (!d_unhashed(next) && next->d_inode)
104 n--;
105 p = p->next;
106 }
Eric Dumazet5160ee62006-01-08 01:03:32 -0800107 list_add_tail(&cursor->d_u.d_child, p);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700108 spin_unlock(&dcache_lock);
109 }
110 }
Josef "Jeff" Sipek0f7fc9e2006-12-08 02:36:35 -0800111 mutex_unlock(&file->f_path.dentry->d_inode->i_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700112 return offset;
113}
114
115/* Relationship between i_mode and the DT_xxx types */
116static inline unsigned char dt_type(struct inode *inode)
117{
118 return (inode->i_mode >> 12) & 15;
119}
120
121/*
122 * Directory is locked and all positive dentries in it are safe, since
123 * for ramfs-type trees they can't go away without unlink() or rmdir(),
124 * both impossible due to the lock on directory.
125 */
126
127int dcache_readdir(struct file * filp, void * dirent, filldir_t filldir)
128{
Josef "Jeff" Sipek0f7fc9e2006-12-08 02:36:35 -0800129 struct dentry *dentry = filp->f_path.dentry;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700130 struct dentry *cursor = filp->private_data;
Eric Dumazet5160ee62006-01-08 01:03:32 -0800131 struct list_head *p, *q = &cursor->d_u.d_child;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700132 ino_t ino;
133 int i = filp->f_pos;
134
135 switch (i) {
136 case 0:
137 ino = dentry->d_inode->i_ino;
138 if (filldir(dirent, ".", 1, i, ino, DT_DIR) < 0)
139 break;
140 filp->f_pos++;
141 i++;
142 /* fallthrough */
143 case 1:
144 ino = parent_ino(dentry);
145 if (filldir(dirent, "..", 2, i, ino, DT_DIR) < 0)
146 break;
147 filp->f_pos++;
148 i++;
149 /* fallthrough */
150 default:
151 spin_lock(&dcache_lock);
Akinobu Mita1bfba4e2006-06-26 00:24:40 -0700152 if (filp->f_pos == 2)
153 list_move(q, &dentry->d_subdirs);
154
Linus Torvalds1da177e2005-04-16 15:20:36 -0700155 for (p=q->next; p != &dentry->d_subdirs; p=p->next) {
156 struct dentry *next;
Eric Dumazet5160ee62006-01-08 01:03:32 -0800157 next = list_entry(p, struct dentry, d_u.d_child);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700158 if (d_unhashed(next) || !next->d_inode)
159 continue;
160
161 spin_unlock(&dcache_lock);
162 if (filldir(dirent, next->d_name.name, next->d_name.len, filp->f_pos, next->d_inode->i_ino, dt_type(next->d_inode)) < 0)
163 return 0;
164 spin_lock(&dcache_lock);
165 /* next is still alive */
Akinobu Mita1bfba4e2006-06-26 00:24:40 -0700166 list_move(q, p);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700167 p = q;
168 filp->f_pos++;
169 }
170 spin_unlock(&dcache_lock);
171 }
172 return 0;
173}
174
175ssize_t generic_read_dir(struct file *filp, char __user *buf, size_t siz, loff_t *ppos)
176{
177 return -EISDIR;
178}
179
Arjan van de Ven4b6f5d22006-03-28 01:56:42 -0800180const struct file_operations simple_dir_operations = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700181 .open = dcache_dir_open,
182 .release = dcache_dir_close,
183 .llseek = dcache_dir_lseek,
184 .read = generic_read_dir,
185 .readdir = dcache_readdir,
Hugh Dickins8ae0b772005-06-25 14:55:41 -0700186 .fsync = simple_sync_file,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700187};
188
Arjan van de Ven92e1d5b2007-02-12 00:55:39 -0800189const struct inode_operations simple_dir_inode_operations = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700190 .lookup = simple_lookup,
191};
192
193/*
194 * Common helper for pseudo-filesystems (sockfs, pipefs, bdev - stuff that
195 * will never be mountable)
196 */
David Howells454e2392006-06-23 02:02:57 -0700197int get_sb_pseudo(struct file_system_type *fs_type, char *name,
Josef 'Jeff' Sipekee9b6d62007-02-12 00:55:41 -0800198 const struct super_operations *ops, unsigned long magic,
David Howells454e2392006-06-23 02:02:57 -0700199 struct vfsmount *mnt)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700200{
201 struct super_block *s = sget(fs_type, NULL, set_anon_super, NULL);
Josef 'Jeff' Sipekee9b6d62007-02-12 00:55:41 -0800202 static const struct super_operations default_ops = {.statfs = simple_statfs};
Linus Torvalds1da177e2005-04-16 15:20:36 -0700203 struct dentry *dentry;
204 struct inode *root;
205 struct qstr d_name = {.name = name, .len = strlen(name)};
206
207 if (IS_ERR(s))
David Howells454e2392006-06-23 02:02:57 -0700208 return PTR_ERR(s);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700209
210 s->s_flags = MS_NOUSER;
211 s->s_maxbytes = ~0ULL;
212 s->s_blocksize = 1024;
213 s->s_blocksize_bits = 10;
214 s->s_magic = magic;
215 s->s_op = ops ? ops : &default_ops;
216 s->s_time_gran = 1;
217 root = new_inode(s);
218 if (!root)
219 goto Enomem;
220 root->i_mode = S_IFDIR | S_IRUSR | S_IWUSR;
221 root->i_uid = root->i_gid = 0;
222 root->i_atime = root->i_mtime = root->i_ctime = CURRENT_TIME;
223 dentry = d_alloc(NULL, &d_name);
224 if (!dentry) {
225 iput(root);
226 goto Enomem;
227 }
228 dentry->d_sb = s;
229 dentry->d_parent = dentry;
230 d_instantiate(dentry, root);
231 s->s_root = dentry;
232 s->s_flags |= MS_ACTIVE;
David Howells454e2392006-06-23 02:02:57 -0700233 return simple_set_mnt(mnt, s);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700234
235Enomem:
236 up_write(&s->s_umount);
237 deactivate_super(s);
David Howells454e2392006-06-23 02:02:57 -0700238 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700239}
240
241int simple_link(struct dentry *old_dentry, struct inode *dir, struct dentry *dentry)
242{
243 struct inode *inode = old_dentry->d_inode;
244
245 inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME;
Dave Hansend8c76e62006-09-30 23:29:04 -0700246 inc_nlink(inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700247 atomic_inc(&inode->i_count);
248 dget(dentry);
249 d_instantiate(dentry, inode);
250 return 0;
251}
252
253static inline int simple_positive(struct dentry *dentry)
254{
255 return dentry->d_inode && !d_unhashed(dentry);
256}
257
258int simple_empty(struct dentry *dentry)
259{
260 struct dentry *child;
261 int ret = 0;
262
263 spin_lock(&dcache_lock);
Eric Dumazet5160ee62006-01-08 01:03:32 -0800264 list_for_each_entry(child, &dentry->d_subdirs, d_u.d_child)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700265 if (simple_positive(child))
266 goto out;
267 ret = 1;
268out:
269 spin_unlock(&dcache_lock);
270 return ret;
271}
272
273int simple_unlink(struct inode *dir, struct dentry *dentry)
274{
275 struct inode *inode = dentry->d_inode;
276
277 inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME;
Dave Hansen9a53c3a2006-09-30 23:29:03 -0700278 drop_nlink(inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700279 dput(dentry);
280 return 0;
281}
282
283int simple_rmdir(struct inode *dir, struct dentry *dentry)
284{
285 if (!simple_empty(dentry))
286 return -ENOTEMPTY;
287
Dave Hansen9a53c3a2006-09-30 23:29:03 -0700288 drop_nlink(dentry->d_inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700289 simple_unlink(dir, dentry);
Dave Hansen9a53c3a2006-09-30 23:29:03 -0700290 drop_nlink(dir);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700291 return 0;
292}
293
294int simple_rename(struct inode *old_dir, struct dentry *old_dentry,
295 struct inode *new_dir, struct dentry *new_dentry)
296{
297 struct inode *inode = old_dentry->d_inode;
298 int they_are_dirs = S_ISDIR(old_dentry->d_inode->i_mode);
299
300 if (!simple_empty(new_dentry))
301 return -ENOTEMPTY;
302
303 if (new_dentry->d_inode) {
304 simple_unlink(new_dir, new_dentry);
305 if (they_are_dirs)
Dave Hansen9a53c3a2006-09-30 23:29:03 -0700306 drop_nlink(old_dir);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700307 } else if (they_are_dirs) {
Dave Hansen9a53c3a2006-09-30 23:29:03 -0700308 drop_nlink(old_dir);
Dave Hansend8c76e62006-09-30 23:29:04 -0700309 inc_nlink(new_dir);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700310 }
311
312 old_dir->i_ctime = old_dir->i_mtime = new_dir->i_ctime =
313 new_dir->i_mtime = inode->i_ctime = CURRENT_TIME;
314
315 return 0;
316}
317
318int simple_readpage(struct file *file, struct page *page)
319{
Pekka J Enbergc0d92cb2006-09-29 01:59:09 -0700320 clear_highpage(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700321 flush_dcache_page(page);
322 SetPageUptodate(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700323 unlock_page(page);
324 return 0;
325}
326
327int simple_prepare_write(struct file *file, struct page *page,
328 unsigned from, unsigned to)
329{
330 if (!PageUptodate(page)) {
331 if (to - from != PAGE_CACHE_SIZE) {
332 void *kaddr = kmap_atomic(page, KM_USER0);
333 memset(kaddr, 0, from);
334 memset(kaddr + to, 0, PAGE_CACHE_SIZE - to);
335 flush_dcache_page(page);
336 kunmap_atomic(kaddr, KM_USER0);
337 }
338 SetPageUptodate(page);
339 }
340 return 0;
341}
342
343int simple_commit_write(struct file *file, struct page *page,
344 unsigned offset, unsigned to)
345{
346 struct inode *inode = page->mapping->host;
347 loff_t pos = ((loff_t)page->index << PAGE_CACHE_SHIFT) + to;
348
349 /*
350 * No need to use i_size_read() here, the i_size
Jes Sorensen1b1dcc12006-01-09 15:59:24 -0800351 * cannot change under us because we hold the i_mutex.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700352 */
353 if (pos > inode->i_size)
354 i_size_write(inode, pos);
355 set_page_dirty(page);
356 return 0;
357}
358
359int simple_fill_super(struct super_block *s, int magic, struct tree_descr *files)
360{
361 static struct super_operations s_ops = {.statfs = simple_statfs};
362 struct inode *inode;
363 struct dentry *root;
364 struct dentry *dentry;
365 int i;
366
367 s->s_blocksize = PAGE_CACHE_SIZE;
368 s->s_blocksize_bits = PAGE_CACHE_SHIFT;
369 s->s_magic = magic;
370 s->s_op = &s_ops;
371 s->s_time_gran = 1;
372
373 inode = new_inode(s);
374 if (!inode)
375 return -ENOMEM;
376 inode->i_mode = S_IFDIR | 0755;
377 inode->i_uid = inode->i_gid = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700378 inode->i_blocks = 0;
379 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
380 inode->i_op = &simple_dir_inode_operations;
381 inode->i_fop = &simple_dir_operations;
Vincent Hanquez7656f322006-02-03 03:04:48 -0800382 inode->i_nlink = 2;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700383 root = d_alloc_root(inode);
384 if (!root) {
385 iput(inode);
386 return -ENOMEM;
387 }
388 for (i = 0; !files->name || files->name[0]; i++, files++) {
389 if (!files->name)
390 continue;
391 dentry = d_alloc_name(root, files->name);
392 if (!dentry)
393 goto out;
394 inode = new_inode(s);
395 if (!inode)
396 goto out;
397 inode->i_mode = S_IFREG | files->mode;
398 inode->i_uid = inode->i_gid = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700399 inode->i_blocks = 0;
400 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
401 inode->i_fop = files->ops;
402 inode->i_ino = i;
403 d_add(dentry, inode);
404 }
405 s->s_root = root;
406 return 0;
407out:
408 d_genocide(root);
409 dput(root);
410 return -ENOMEM;
411}
412
413static DEFINE_SPINLOCK(pin_fs_lock);
414
Trond Myklebust1f5ce9e2006-06-09 09:34:16 -0400415int simple_pin_fs(struct file_system_type *type, struct vfsmount **mount, int *count)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700416{
417 struct vfsmount *mnt = NULL;
418 spin_lock(&pin_fs_lock);
419 if (unlikely(!*mount)) {
420 spin_unlock(&pin_fs_lock);
Trond Myklebust1f5ce9e2006-06-09 09:34:16 -0400421 mnt = vfs_kern_mount(type, 0, type->name, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700422 if (IS_ERR(mnt))
423 return PTR_ERR(mnt);
424 spin_lock(&pin_fs_lock);
425 if (!*mount)
426 *mount = mnt;
427 }
428 mntget(*mount);
429 ++*count;
430 spin_unlock(&pin_fs_lock);
431 mntput(mnt);
432 return 0;
433}
434
435void simple_release_fs(struct vfsmount **mount, int *count)
436{
437 struct vfsmount *mnt;
438 spin_lock(&pin_fs_lock);
439 mnt = *mount;
440 if (!--*count)
441 *mount = NULL;
442 spin_unlock(&pin_fs_lock);
443 mntput(mnt);
444}
445
446ssize_t simple_read_from_buffer(void __user *to, size_t count, loff_t *ppos,
447 const void *from, size_t available)
448{
449 loff_t pos = *ppos;
450 if (pos < 0)
451 return -EINVAL;
452 if (pos >= available)
453 return 0;
454 if (count > available - pos)
455 count = available - pos;
456 if (copy_to_user(to, from + pos, count))
457 return -EFAULT;
458 *ppos = pos + count;
459 return count;
460}
461
462/*
463 * Transaction based IO.
464 * The file expects a single write which triggers the transaction, and then
465 * possibly a read which collects the result - which is stored in a
466 * file-local buffer.
467 */
468char *simple_transaction_get(struct file *file, const char __user *buf, size_t size)
469{
470 struct simple_transaction_argresp *ar;
471 static DEFINE_SPINLOCK(simple_transaction_lock);
472
473 if (size > SIMPLE_TRANSACTION_LIMIT - 1)
474 return ERR_PTR(-EFBIG);
475
476 ar = (struct simple_transaction_argresp *)get_zeroed_page(GFP_KERNEL);
477 if (!ar)
478 return ERR_PTR(-ENOMEM);
479
480 spin_lock(&simple_transaction_lock);
481
482 /* only one write allowed per open */
483 if (file->private_data) {
484 spin_unlock(&simple_transaction_lock);
485 free_page((unsigned long)ar);
486 return ERR_PTR(-EBUSY);
487 }
488
489 file->private_data = ar;
490
491 spin_unlock(&simple_transaction_lock);
492
493 if (copy_from_user(ar->data, buf, size))
494 return ERR_PTR(-EFAULT);
495
496 return ar->data;
497}
498
499ssize_t simple_transaction_read(struct file *file, char __user *buf, size_t size, loff_t *pos)
500{
501 struct simple_transaction_argresp *ar = file->private_data;
502
503 if (!ar)
504 return 0;
505 return simple_read_from_buffer(buf, size, pos, ar->data, ar->size);
506}
507
508int simple_transaction_release(struct inode *inode, struct file *file)
509{
510 free_page((unsigned long)file->private_data);
511 return 0;
512}
513
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200514/* Simple attribute files */
515
516struct simple_attr {
517 u64 (*get)(void *);
518 void (*set)(void *, u64);
519 char get_buf[24]; /* enough to store a u64 and "\n\0" */
520 char set_buf[24];
521 void *data;
522 const char *fmt; /* format for read operation */
Ingo Molnar7cf34c72006-03-23 03:00:36 -0800523 struct mutex mutex; /* protects access to these buffers */
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200524};
525
526/* simple_attr_open is called by an actual attribute open file operation
527 * to set the attribute specific access operations. */
528int simple_attr_open(struct inode *inode, struct file *file,
529 u64 (*get)(void *), void (*set)(void *, u64),
530 const char *fmt)
531{
532 struct simple_attr *attr;
533
534 attr = kmalloc(sizeof(*attr), GFP_KERNEL);
535 if (!attr)
536 return -ENOMEM;
537
538 attr->get = get;
539 attr->set = set;
Theodore Ts'o8e18e292006-09-27 01:50:46 -0700540 attr->data = inode->i_private;
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200541 attr->fmt = fmt;
Ingo Molnar7cf34c72006-03-23 03:00:36 -0800542 mutex_init(&attr->mutex);
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200543
544 file->private_data = attr;
545
546 return nonseekable_open(inode, file);
547}
548
549int simple_attr_close(struct inode *inode, struct file *file)
550{
551 kfree(file->private_data);
552 return 0;
553}
554
555/* read from the buffer that is filled with the get function */
556ssize_t simple_attr_read(struct file *file, char __user *buf,
557 size_t len, loff_t *ppos)
558{
559 struct simple_attr *attr;
560 size_t size;
561 ssize_t ret;
562
563 attr = file->private_data;
564
565 if (!attr->get)
566 return -EACCES;
567
Ingo Molnar7cf34c72006-03-23 03:00:36 -0800568 mutex_lock(&attr->mutex);
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200569 if (*ppos) /* continued read */
570 size = strlen(attr->get_buf);
571 else /* first read */
572 size = scnprintf(attr->get_buf, sizeof(attr->get_buf),
573 attr->fmt,
574 (unsigned long long)attr->get(attr->data));
575
576 ret = simple_read_from_buffer(buf, len, ppos, attr->get_buf, size);
Ingo Molnar7cf34c72006-03-23 03:00:36 -0800577 mutex_unlock(&attr->mutex);
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200578 return ret;
579}
580
581/* interpret the buffer as a number to call the set function with */
582ssize_t simple_attr_write(struct file *file, const char __user *buf,
583 size_t len, loff_t *ppos)
584{
585 struct simple_attr *attr;
586 u64 val;
587 size_t size;
588 ssize_t ret;
589
590 attr = file->private_data;
591
592 if (!attr->set)
593 return -EACCES;
594
Ingo Molnar7cf34c72006-03-23 03:00:36 -0800595 mutex_lock(&attr->mutex);
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200596 ret = -EFAULT;
597 size = min(sizeof(attr->set_buf) - 1, len);
598 if (copy_from_user(attr->set_buf, buf, size))
599 goto out;
600
601 ret = len; /* claim we got the whole input */
602 attr->set_buf[size] = '\0';
603 val = simple_strtol(attr->set_buf, NULL, 0);
604 attr->set(attr->data, val);
605out:
Ingo Molnar7cf34c72006-03-23 03:00:36 -0800606 mutex_unlock(&attr->mutex);
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200607 return ret;
608}
609
Linus Torvalds1da177e2005-04-16 15:20:36 -0700610EXPORT_SYMBOL(dcache_dir_close);
611EXPORT_SYMBOL(dcache_dir_lseek);
612EXPORT_SYMBOL(dcache_dir_open);
613EXPORT_SYMBOL(dcache_readdir);
614EXPORT_SYMBOL(generic_read_dir);
615EXPORT_SYMBOL(get_sb_pseudo);
616EXPORT_SYMBOL(simple_commit_write);
617EXPORT_SYMBOL(simple_dir_inode_operations);
618EXPORT_SYMBOL(simple_dir_operations);
619EXPORT_SYMBOL(simple_empty);
620EXPORT_SYMBOL(d_alloc_name);
621EXPORT_SYMBOL(simple_fill_super);
622EXPORT_SYMBOL(simple_getattr);
623EXPORT_SYMBOL(simple_link);
624EXPORT_SYMBOL(simple_lookup);
625EXPORT_SYMBOL(simple_pin_fs);
626EXPORT_SYMBOL(simple_prepare_write);
627EXPORT_SYMBOL(simple_readpage);
628EXPORT_SYMBOL(simple_release_fs);
629EXPORT_SYMBOL(simple_rename);
630EXPORT_SYMBOL(simple_rmdir);
631EXPORT_SYMBOL(simple_statfs);
632EXPORT_SYMBOL(simple_sync_file);
633EXPORT_SYMBOL(simple_unlink);
634EXPORT_SYMBOL(simple_read_from_buffer);
635EXPORT_SYMBOL(simple_transaction_get);
636EXPORT_SYMBOL(simple_transaction_read);
637EXPORT_SYMBOL(simple_transaction_release);
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200638EXPORT_SYMBOL_GPL(simple_attr_open);
639EXPORT_SYMBOL_GPL(simple_attr_close);
640EXPORT_SYMBOL_GPL(simple_attr_read);
641EXPORT_SYMBOL_GPL(simple_attr_write);