blob: 889311e3d06b66c6ea99c581f96a9d2774950d12 [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>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +09008#include <linux/slab.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -07009#include <linux/mount.h>
10#include <linux/vfs.h>
npiggin@suse.de7bb46a62010-05-27 01:05:33 +100011#include <linux/quotaops.h>
Ingo Molnar7cf34c72006-03-23 03:00:36 -080012#include <linux/mutex.h>
Christoph Hellwig25961102007-10-21 16:42:05 -070013#include <linux/exportfs.h>
Al Virod5aacad2009-06-07 14:56:44 -040014#include <linux/writeback.h>
15#include <linux/buffer_head.h>
Ingo Molnar7cf34c72006-03-23 03:00:36 -080016
Linus Torvalds1da177e2005-04-16 15:20:36 -070017#include <asm/uaccess.h>
18
Nick Pigginda502952011-01-07 17:49:33 +110019static inline int simple_positive(struct dentry *dentry)
20{
21 return dentry->d_inode && !d_unhashed(dentry);
22}
23
Linus Torvalds1da177e2005-04-16 15:20:36 -070024int simple_getattr(struct vfsmount *mnt, struct dentry *dentry,
25 struct kstat *stat)
26{
27 struct inode *inode = dentry->d_inode;
28 generic_fillattr(inode, stat);
29 stat->blocks = inode->i_mapping->nrpages << (PAGE_CACHE_SHIFT - 9);
30 return 0;
31}
32
David Howells726c3342006-06-23 02:02:58 -070033int simple_statfs(struct dentry *dentry, struct kstatfs *buf)
Linus Torvalds1da177e2005-04-16 15:20:36 -070034{
David Howells726c3342006-06-23 02:02:58 -070035 buf->f_type = dentry->d_sb->s_magic;
Linus Torvalds1da177e2005-04-16 15:20:36 -070036 buf->f_bsize = PAGE_CACHE_SIZE;
37 buf->f_namelen = NAME_MAX;
38 return 0;
39}
40
41/*
42 * Retaining negative dentries for an in-memory filesystem just wastes
43 * memory and lookup time: arrange for them to be deleted immediately.
44 */
Nick Pigginfe15ce42011-01-07 17:49:23 +110045static int simple_delete_dentry(const struct dentry *dentry)
Linus Torvalds1da177e2005-04-16 15:20:36 -070046{
47 return 1;
48}
49
50/*
51 * Lookup the data. This is trivial - if the dentry didn't already
52 * exist, we know it is negative. Set d_op to delete negative dentries.
53 */
54struct dentry *simple_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd)
55{
Al Viro3ba13d12009-02-20 06:02:22 +000056 static const struct dentry_operations simple_dentry_operations = {
Linus Torvalds1da177e2005-04-16 15:20:36 -070057 .d_delete = simple_delete_dentry,
58 };
59
60 if (dentry->d_name.len > NAME_MAX)
61 return ERR_PTR(-ENAMETOOLONG);
Nick Pigginfb045ad2011-01-07 17:49:55 +110062 d_set_d_op(dentry, &simple_dentry_operations);
Linus Torvalds1da177e2005-04-16 15:20:36 -070063 d_add(dentry, NULL);
64 return NULL;
65}
66
Linus Torvalds1da177e2005-04-16 15:20:36 -070067int dcache_dir_open(struct inode *inode, struct file *file)
68{
69 static struct qstr cursor_name = {.len = 1, .name = "."};
70
Josef "Jeff" Sipek0f7fc9e2006-12-08 02:36:35 -080071 file->private_data = d_alloc(file->f_path.dentry, &cursor_name);
Linus Torvalds1da177e2005-04-16 15:20:36 -070072
73 return file->private_data ? 0 : -ENOMEM;
74}
75
76int dcache_dir_close(struct inode *inode, struct file *file)
77{
78 dput(file->private_data);
79 return 0;
80}
81
82loff_t dcache_dir_lseek(struct file *file, loff_t offset, int origin)
83{
Nick Piggin2fd6b7f2011-01-07 17:49:34 +110084 struct dentry *dentry = file->f_path.dentry;
85 mutex_lock(&dentry->d_inode->i_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -070086 switch (origin) {
87 case 1:
88 offset += file->f_pos;
89 case 0:
90 if (offset >= 0)
91 break;
92 default:
Nick Piggin2fd6b7f2011-01-07 17:49:34 +110093 mutex_unlock(&dentry->d_inode->i_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -070094 return -EINVAL;
95 }
96 if (offset != file->f_pos) {
97 file->f_pos = offset;
98 if (file->f_pos >= 2) {
99 struct list_head *p;
100 struct dentry *cursor = file->private_data;
101 loff_t n = file->f_pos - 2;
102
Nick Piggin2fd6b7f2011-01-07 17:49:34 +1100103 spin_lock(&dentry->d_lock);
104 /* d_lock not required for cursor */
Eric Dumazet5160ee62006-01-08 01:03:32 -0800105 list_del(&cursor->d_u.d_child);
Nick Piggin2fd6b7f2011-01-07 17:49:34 +1100106 p = dentry->d_subdirs.next;
107 while (n && p != &dentry->d_subdirs) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700108 struct dentry *next;
Eric Dumazet5160ee62006-01-08 01:03:32 -0800109 next = list_entry(p, struct dentry, d_u.d_child);
Nick Piggin2fd6b7f2011-01-07 17:49:34 +1100110 spin_lock_nested(&next->d_lock, DENTRY_D_LOCK_NESTED);
Nick Pigginda502952011-01-07 17:49:33 +1100111 if (simple_positive(next))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700112 n--;
Nick Pigginda502952011-01-07 17:49:33 +1100113 spin_unlock(&next->d_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700114 p = p->next;
115 }
Eric Dumazet5160ee62006-01-08 01:03:32 -0800116 list_add_tail(&cursor->d_u.d_child, p);
Nick Piggin2fd6b7f2011-01-07 17:49:34 +1100117 spin_unlock(&dentry->d_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700118 }
119 }
Nick Piggin2fd6b7f2011-01-07 17:49:34 +1100120 mutex_unlock(&dentry->d_inode->i_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700121 return offset;
122}
123
124/* Relationship between i_mode and the DT_xxx types */
125static inline unsigned char dt_type(struct inode *inode)
126{
127 return (inode->i_mode >> 12) & 15;
128}
129
130/*
131 * Directory is locked and all positive dentries in it are safe, since
132 * for ramfs-type trees they can't go away without unlink() or rmdir(),
133 * both impossible due to the lock on directory.
134 */
135
136int dcache_readdir(struct file * filp, void * dirent, filldir_t filldir)
137{
Josef "Jeff" Sipek0f7fc9e2006-12-08 02:36:35 -0800138 struct dentry *dentry = filp->f_path.dentry;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700139 struct dentry *cursor = filp->private_data;
Eric Dumazet5160ee62006-01-08 01:03:32 -0800140 struct list_head *p, *q = &cursor->d_u.d_child;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700141 ino_t ino;
142 int i = filp->f_pos;
143
144 switch (i) {
145 case 0:
146 ino = dentry->d_inode->i_ino;
147 if (filldir(dirent, ".", 1, i, ino, DT_DIR) < 0)
148 break;
149 filp->f_pos++;
150 i++;
151 /* fallthrough */
152 case 1:
153 ino = parent_ino(dentry);
154 if (filldir(dirent, "..", 2, i, ino, DT_DIR) < 0)
155 break;
156 filp->f_pos++;
157 i++;
158 /* fallthrough */
159 default:
Nick Piggin2fd6b7f2011-01-07 17:49:34 +1100160 spin_lock(&dentry->d_lock);
Akinobu Mita1bfba4e2006-06-26 00:24:40 -0700161 if (filp->f_pos == 2)
162 list_move(q, &dentry->d_subdirs);
163
Linus Torvalds1da177e2005-04-16 15:20:36 -0700164 for (p=q->next; p != &dentry->d_subdirs; p=p->next) {
165 struct dentry *next;
Eric Dumazet5160ee62006-01-08 01:03:32 -0800166 next = list_entry(p, struct dentry, d_u.d_child);
Nick Pigginda502952011-01-07 17:49:33 +1100167 spin_lock_nested(&next->d_lock, DENTRY_D_LOCK_NESTED);
168 if (!simple_positive(next)) {
169 spin_unlock(&next->d_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700170 continue;
Nick Pigginda502952011-01-07 17:49:33 +1100171 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700172
Nick Pigginda502952011-01-07 17:49:33 +1100173 spin_unlock(&next->d_lock);
Nick Piggin2fd6b7f2011-01-07 17:49:34 +1100174 spin_unlock(&dentry->d_lock);
Ronni Nielsen0f8952c22007-05-09 06:44:57 +0200175 if (filldir(dirent, next->d_name.name,
176 next->d_name.len, filp->f_pos,
177 next->d_inode->i_ino,
178 dt_type(next->d_inode)) < 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700179 return 0;
Nick Piggin2fd6b7f2011-01-07 17:49:34 +1100180 spin_lock(&dentry->d_lock);
181 spin_lock_nested(&next->d_lock, DENTRY_D_LOCK_NESTED);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700182 /* next is still alive */
Akinobu Mita1bfba4e2006-06-26 00:24:40 -0700183 list_move(q, p);
Nick Piggin2fd6b7f2011-01-07 17:49:34 +1100184 spin_unlock(&next->d_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700185 p = q;
186 filp->f_pos++;
187 }
Nick Piggin2fd6b7f2011-01-07 17:49:34 +1100188 spin_unlock(&dentry->d_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700189 }
190 return 0;
191}
192
193ssize_t generic_read_dir(struct file *filp, char __user *buf, size_t siz, loff_t *ppos)
194{
195 return -EISDIR;
196}
197
Arjan van de Ven4b6f5d22006-03-28 01:56:42 -0800198const struct file_operations simple_dir_operations = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700199 .open = dcache_dir_open,
200 .release = dcache_dir_close,
201 .llseek = dcache_dir_lseek,
202 .read = generic_read_dir,
203 .readdir = dcache_readdir,
Christoph Hellwig1b061d92010-05-26 17:53:41 +0200204 .fsync = noop_fsync,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700205};
206
Arjan van de Ven92e1d5b2007-02-12 00:55:39 -0800207const struct inode_operations simple_dir_inode_operations = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700208 .lookup = simple_lookup,
209};
210
Hugh Dickins759b9772007-03-05 00:30:28 -0800211static const struct super_operations simple_super_operations = {
212 .statfs = simple_statfs,
213};
214
Linus Torvalds1da177e2005-04-16 15:20:36 -0700215/*
216 * Common helper for pseudo-filesystems (sockfs, pipefs, bdev - stuff that
217 * will never be mountable)
218 */
Al Viro51139ad2010-07-25 23:47:46 +0400219struct dentry *mount_pseudo(struct file_system_type *fs_type, char *name,
220 const struct super_operations *ops, unsigned long magic)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700221{
222 struct super_block *s = sget(fs_type, NULL, set_anon_super, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700223 struct dentry *dentry;
224 struct inode *root;
225 struct qstr d_name = {.name = name, .len = strlen(name)};
226
227 if (IS_ERR(s))
Al Viro51139ad2010-07-25 23:47:46 +0400228 return ERR_CAST(s);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700229
230 s->s_flags = MS_NOUSER;
Jeff Layton89a4eb42009-08-18 14:11:08 -0700231 s->s_maxbytes = MAX_LFS_FILESIZE;
Alex Nixon3971e1a2008-07-29 22:33:03 -0700232 s->s_blocksize = PAGE_SIZE;
233 s->s_blocksize_bits = PAGE_SHIFT;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700234 s->s_magic = magic;
Hugh Dickins759b9772007-03-05 00:30:28 -0800235 s->s_op = ops ? ops : &simple_super_operations;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700236 s->s_time_gran = 1;
237 root = new_inode(s);
238 if (!root)
239 goto Enomem;
Jeff Layton1a1c9bb2007-05-08 00:32:31 -0700240 /*
241 * since this is the first inode, make it number 1. New inodes created
242 * after this must take care not to collide with it (by passing
243 * max_reserved of 1 to iunique).
244 */
245 root->i_ino = 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700246 root->i_mode = S_IFDIR | S_IRUSR | S_IWUSR;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700247 root->i_atime = root->i_mtime = root->i_ctime = CURRENT_TIME;
248 dentry = d_alloc(NULL, &d_name);
249 if (!dentry) {
250 iput(root);
251 goto Enomem;
252 }
253 dentry->d_sb = s;
254 dentry->d_parent = dentry;
255 d_instantiate(dentry, root);
256 s->s_root = dentry;
257 s->s_flags |= MS_ACTIVE;
Al Viro51139ad2010-07-25 23:47:46 +0400258 return dget(s->s_root);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700259
260Enomem:
Al Viro6f5bbff2009-05-06 01:34:22 -0400261 deactivate_locked_super(s);
Al Viro51139ad2010-07-25 23:47:46 +0400262 return ERR_PTR(-ENOMEM);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700263}
264
265int simple_link(struct dentry *old_dentry, struct inode *dir, struct dentry *dentry)
266{
267 struct inode *inode = old_dentry->d_inode;
268
269 inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME;
Dave Hansend8c76e62006-09-30 23:29:04 -0700270 inc_nlink(inode);
Al Viro7de9c6ee2010-10-23 11:11:40 -0400271 ihold(inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700272 dget(dentry);
273 d_instantiate(dentry, inode);
274 return 0;
275}
276
Linus Torvalds1da177e2005-04-16 15:20:36 -0700277int simple_empty(struct dentry *dentry)
278{
279 struct dentry *child;
280 int ret = 0;
281
Nick Piggin2fd6b7f2011-01-07 17:49:34 +1100282 spin_lock(&dentry->d_lock);
Nick Pigginda502952011-01-07 17:49:33 +1100283 list_for_each_entry(child, &dentry->d_subdirs, d_u.d_child) {
284 spin_lock_nested(&child->d_lock, DENTRY_D_LOCK_NESTED);
285 if (simple_positive(child)) {
286 spin_unlock(&child->d_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700287 goto out;
Nick Pigginda502952011-01-07 17:49:33 +1100288 }
289 spin_unlock(&child->d_lock);
290 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700291 ret = 1;
292out:
Nick Piggin2fd6b7f2011-01-07 17:49:34 +1100293 spin_unlock(&dentry->d_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700294 return ret;
295}
296
297int simple_unlink(struct inode *dir, struct dentry *dentry)
298{
299 struct inode *inode = dentry->d_inode;
300
301 inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME;
Dave Hansen9a53c3a2006-09-30 23:29:03 -0700302 drop_nlink(inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700303 dput(dentry);
304 return 0;
305}
306
307int simple_rmdir(struct inode *dir, struct dentry *dentry)
308{
309 if (!simple_empty(dentry))
310 return -ENOTEMPTY;
311
Dave Hansen9a53c3a2006-09-30 23:29:03 -0700312 drop_nlink(dentry->d_inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700313 simple_unlink(dir, dentry);
Dave Hansen9a53c3a2006-09-30 23:29:03 -0700314 drop_nlink(dir);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700315 return 0;
316}
317
318int simple_rename(struct inode *old_dir, struct dentry *old_dentry,
319 struct inode *new_dir, struct dentry *new_dentry)
320{
321 struct inode *inode = old_dentry->d_inode;
322 int they_are_dirs = S_ISDIR(old_dentry->d_inode->i_mode);
323
324 if (!simple_empty(new_dentry))
325 return -ENOTEMPTY;
326
327 if (new_dentry->d_inode) {
328 simple_unlink(new_dir, new_dentry);
329 if (they_are_dirs)
Dave Hansen9a53c3a2006-09-30 23:29:03 -0700330 drop_nlink(old_dir);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700331 } else if (they_are_dirs) {
Dave Hansen9a53c3a2006-09-30 23:29:03 -0700332 drop_nlink(old_dir);
Dave Hansend8c76e62006-09-30 23:29:04 -0700333 inc_nlink(new_dir);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700334 }
335
336 old_dir->i_ctime = old_dir->i_mtime = new_dir->i_ctime =
337 new_dir->i_mtime = inode->i_ctime = CURRENT_TIME;
338
339 return 0;
340}
341
npiggin@suse.de7bb46a62010-05-27 01:05:33 +1000342/**
Christoph Hellwigeef23802010-06-04 11:30:01 +0200343 * simple_setattr - setattr for simple filesystem
npiggin@suse.de7bb46a62010-05-27 01:05:33 +1000344 * @dentry: dentry
345 * @iattr: iattr structure
346 *
347 * Returns 0 on success, -error on failure.
348 *
Christoph Hellwigeef23802010-06-04 11:30:01 +0200349 * simple_setattr is a simple ->setattr implementation without a proper
350 * implementation of size changes.
351 *
352 * It can either be used for in-memory filesystems or special files
353 * on simple regular filesystems. Anything that needs to change on-disk
354 * or wire state on size changes needs its own setattr method.
npiggin@suse.de7bb46a62010-05-27 01:05:33 +1000355 */
356int simple_setattr(struct dentry *dentry, struct iattr *iattr)
357{
358 struct inode *inode = dentry->d_inode;
359 int error;
360
Christoph Hellwigeef23802010-06-04 11:30:01 +0200361 WARN_ON_ONCE(inode->i_op->truncate);
362
npiggin@suse.de7bb46a62010-05-27 01:05:33 +1000363 error = inode_change_ok(inode, iattr);
364 if (error)
365 return error;
366
Christoph Hellwig2c27c652010-06-04 11:30:04 +0200367 if (iattr->ia_valid & ATTR_SIZE)
368 truncate_setsize(inode, iattr->ia_size);
Christoph Hellwig6a1a90a2010-06-04 11:30:00 +0200369 setattr_copy(inode, iattr);
Christoph Hellwigeef23802010-06-04 11:30:01 +0200370 mark_inode_dirty(inode);
371 return 0;
npiggin@suse.de7bb46a62010-05-27 01:05:33 +1000372}
373EXPORT_SYMBOL(simple_setattr);
374
Linus Torvalds1da177e2005-04-16 15:20:36 -0700375int simple_readpage(struct file *file, struct page *page)
376{
Pekka J Enbergc0d92cb2006-09-29 01:59:09 -0700377 clear_highpage(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700378 flush_dcache_page(page);
379 SetPageUptodate(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700380 unlock_page(page);
381 return 0;
382}
383
Nick Pigginafddba42007-10-16 01:25:01 -0700384int simple_write_begin(struct file *file, struct address_space *mapping,
385 loff_t pos, unsigned len, unsigned flags,
386 struct page **pagep, void **fsdata)
387{
388 struct page *page;
389 pgoff_t index;
Nick Pigginafddba42007-10-16 01:25:01 -0700390
391 index = pos >> PAGE_CACHE_SHIFT;
Nick Pigginafddba42007-10-16 01:25:01 -0700392
Nick Piggin54566b22009-01-04 12:00:53 -0800393 page = grab_cache_page_write_begin(mapping, index, flags);
Nick Pigginafddba42007-10-16 01:25:01 -0700394 if (!page)
395 return -ENOMEM;
396
397 *pagep = page;
398
Boaz Harrosh193cf4b2010-01-12 16:18:08 +0200399 if (!PageUptodate(page) && (len != PAGE_CACHE_SIZE)) {
400 unsigned from = pos & (PAGE_CACHE_SIZE - 1);
401
402 zero_user_segments(page, 0, from, from + len, PAGE_CACHE_SIZE);
403 }
404 return 0;
Nick Pigginafddba42007-10-16 01:25:01 -0700405}
406
Boaz Harroshad2a722f2010-01-12 15:13:47 +0200407/**
408 * simple_write_end - .write_end helper for non-block-device FSes
409 * @available: See .write_end of address_space_operations
410 * @file: "
411 * @mapping: "
412 * @pos: "
413 * @len: "
414 * @copied: "
415 * @page: "
416 * @fsdata: "
417 *
418 * simple_write_end does the minimum needed for updating a page after writing is
419 * done. It has the same API signature as the .write_end of
420 * address_space_operations vector. So it can just be set onto .write_end for
421 * FSes that don't need any other processing. i_mutex is assumed to be held.
422 * Block based filesystems should use generic_write_end().
423 * NOTE: Even though i_size might get updated by this function, mark_inode_dirty
424 * is not called, so a filesystem that actually does store data in .write_inode
425 * should extend on what's done here with a call to mark_inode_dirty() in the
426 * case that i_size has changed.
427 */
428int simple_write_end(struct file *file, struct address_space *mapping,
429 loff_t pos, unsigned len, unsigned copied,
430 struct page *page, void *fsdata)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700431{
432 struct inode *inode = page->mapping->host;
Boaz Harroshad2a722f2010-01-12 15:13:47 +0200433 loff_t last_pos = pos + copied;
434
435 /* zero the stale part of the page if we did a short copy */
436 if (copied < len) {
437 unsigned from = pos & (PAGE_CACHE_SIZE - 1);
438
439 zero_user(page, from + copied, len - copied);
440 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700441
Nick Piggin955eff52007-02-20 13:58:08 -0800442 if (!PageUptodate(page))
443 SetPageUptodate(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700444 /*
445 * No need to use i_size_read() here, the i_size
Jes Sorensen1b1dcc12006-01-09 15:59:24 -0800446 * cannot change under us because we hold the i_mutex.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700447 */
Boaz Harroshad2a722f2010-01-12 15:13:47 +0200448 if (last_pos > inode->i_size)
449 i_size_write(inode, last_pos);
450
Linus Torvalds1da177e2005-04-16 15:20:36 -0700451 set_page_dirty(page);
Nick Pigginafddba42007-10-16 01:25:01 -0700452 unlock_page(page);
453 page_cache_release(page);
454
455 return copied;
456}
457
Jeff Layton1a1c9bb2007-05-08 00:32:31 -0700458/*
459 * the inodes created here are not hashed. If you use iunique to generate
460 * unique inode values later for this filesystem, then you must take care
461 * to pass it an appropriate max_reserved value to avoid collisions.
462 */
Roberto Sassu7d683a02010-06-03 11:58:28 +0200463int simple_fill_super(struct super_block *s, unsigned long magic,
464 struct tree_descr *files)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700465{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700466 struct inode *inode;
467 struct dentry *root;
468 struct dentry *dentry;
469 int i;
470
471 s->s_blocksize = PAGE_CACHE_SIZE;
472 s->s_blocksize_bits = PAGE_CACHE_SHIFT;
473 s->s_magic = magic;
Hugh Dickins759b9772007-03-05 00:30:28 -0800474 s->s_op = &simple_super_operations;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700475 s->s_time_gran = 1;
476
477 inode = new_inode(s);
478 if (!inode)
479 return -ENOMEM;
Jeff Layton1a1c9bb2007-05-08 00:32:31 -0700480 /*
481 * because the root inode is 1, the files array must not contain an
482 * entry at index 1
483 */
484 inode->i_ino = 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700485 inode->i_mode = S_IFDIR | 0755;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700486 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
487 inode->i_op = &simple_dir_inode_operations;
488 inode->i_fop = &simple_dir_operations;
Vincent Hanquez7656f322006-02-03 03:04:48 -0800489 inode->i_nlink = 2;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700490 root = d_alloc_root(inode);
491 if (!root) {
492 iput(inode);
493 return -ENOMEM;
494 }
495 for (i = 0; !files->name || files->name[0]; i++, files++) {
496 if (!files->name)
497 continue;
Jeff Layton1a1c9bb2007-05-08 00:32:31 -0700498
499 /* warn if it tries to conflict with the root inode */
500 if (unlikely(i == 1))
501 printk(KERN_WARNING "%s: %s passed in a files array"
502 "with an index of 1!\n", __func__,
503 s->s_type->name);
504
Linus Torvalds1da177e2005-04-16 15:20:36 -0700505 dentry = d_alloc_name(root, files->name);
506 if (!dentry)
507 goto out;
508 inode = new_inode(s);
509 if (!inode)
510 goto out;
511 inode->i_mode = S_IFREG | files->mode;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700512 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
513 inode->i_fop = files->ops;
514 inode->i_ino = i;
515 d_add(dentry, inode);
516 }
517 s->s_root = root;
518 return 0;
519out:
520 d_genocide(root);
521 dput(root);
522 return -ENOMEM;
523}
524
525static DEFINE_SPINLOCK(pin_fs_lock);
526
Trond Myklebust1f5ce9e2006-06-09 09:34:16 -0400527int simple_pin_fs(struct file_system_type *type, struct vfsmount **mount, int *count)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700528{
529 struct vfsmount *mnt = NULL;
530 spin_lock(&pin_fs_lock);
531 if (unlikely(!*mount)) {
532 spin_unlock(&pin_fs_lock);
Trond Myklebust1f5ce9e2006-06-09 09:34:16 -0400533 mnt = vfs_kern_mount(type, 0, type->name, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700534 if (IS_ERR(mnt))
535 return PTR_ERR(mnt);
536 spin_lock(&pin_fs_lock);
537 if (!*mount)
538 *mount = mnt;
539 }
540 mntget(*mount);
541 ++*count;
542 spin_unlock(&pin_fs_lock);
543 mntput(mnt);
544 return 0;
545}
546
547void simple_release_fs(struct vfsmount **mount, int *count)
548{
549 struct vfsmount *mnt;
550 spin_lock(&pin_fs_lock);
551 mnt = *mount;
552 if (!--*count)
553 *mount = NULL;
554 spin_unlock(&pin_fs_lock);
555 mntput(mnt);
556}
557
Akinobu Mita6d1029b2008-07-04 09:59:51 -0700558/**
559 * simple_read_from_buffer - copy data from the buffer to user space
560 * @to: the user space buffer to read to
561 * @count: the maximum number of bytes to read
562 * @ppos: the current position in the buffer
563 * @from: the buffer to read from
564 * @available: the size of the buffer
565 *
566 * The simple_read_from_buffer() function reads up to @count bytes from the
567 * buffer @from at offset @ppos into the user space address starting at @to.
568 *
569 * On success, the number of bytes read is returned and the offset @ppos is
570 * advanced by this number, or negative value is returned on error.
571 **/
Linus Torvalds1da177e2005-04-16 15:20:36 -0700572ssize_t simple_read_from_buffer(void __user *to, size_t count, loff_t *ppos,
573 const void *from, size_t available)
574{
575 loff_t pos = *ppos;
Steven Rostedt14be2742009-09-18 13:05:42 -0700576 size_t ret;
577
Linus Torvalds1da177e2005-04-16 15:20:36 -0700578 if (pos < 0)
579 return -EINVAL;
Steven Rostedt14be2742009-09-18 13:05:42 -0700580 if (pos >= available || !count)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700581 return 0;
582 if (count > available - pos)
583 count = available - pos;
Steven Rostedt14be2742009-09-18 13:05:42 -0700584 ret = copy_to_user(to, from + pos, count);
585 if (ret == count)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700586 return -EFAULT;
Steven Rostedt14be2742009-09-18 13:05:42 -0700587 count -= ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700588 *ppos = pos + count;
589 return count;
590}
591
Akinobu Mita6d1029b2008-07-04 09:59:51 -0700592/**
Jiri Slaby6a727b42010-05-01 23:51:22 +0200593 * simple_write_to_buffer - copy data from user space to the buffer
594 * @to: the buffer to write to
595 * @available: the size of the buffer
596 * @ppos: the current position in the buffer
597 * @from: the user space buffer to read from
598 * @count: the maximum number of bytes to read
599 *
600 * The simple_write_to_buffer() function reads up to @count bytes from the user
601 * space address starting at @from into the buffer @to at offset @ppos.
602 *
603 * On success, the number of bytes written is returned and the offset @ppos is
604 * advanced by this number, or negative value is returned on error.
605 **/
606ssize_t simple_write_to_buffer(void *to, size_t available, loff_t *ppos,
607 const void __user *from, size_t count)
608{
609 loff_t pos = *ppos;
610 size_t res;
611
612 if (pos < 0)
613 return -EINVAL;
614 if (pos >= available || !count)
615 return 0;
616 if (count > available - pos)
617 count = available - pos;
618 res = copy_from_user(to + pos, from, count);
619 if (res == count)
620 return -EFAULT;
621 count -= res;
622 *ppos = pos + count;
623 return count;
624}
625
626/**
Akinobu Mita6d1029b2008-07-04 09:59:51 -0700627 * memory_read_from_buffer - copy data from the buffer
628 * @to: the kernel space buffer to read to
629 * @count: the maximum number of bytes to read
630 * @ppos: the current position in the buffer
631 * @from: the buffer to read from
632 * @available: the size of the buffer
633 *
634 * The memory_read_from_buffer() function reads up to @count bytes from the
635 * buffer @from at offset @ppos into the kernel space address starting at @to.
636 *
637 * On success, the number of bytes read is returned and the offset @ppos is
638 * advanced by this number, or negative value is returned on error.
639 **/
Akinobu Mita93b07112008-06-05 22:46:21 -0700640ssize_t memory_read_from_buffer(void *to, size_t count, loff_t *ppos,
641 const void *from, size_t available)
642{
643 loff_t pos = *ppos;
644
645 if (pos < 0)
646 return -EINVAL;
647 if (pos >= available)
648 return 0;
649 if (count > available - pos)
650 count = available - pos;
651 memcpy(to, from + pos, count);
652 *ppos = pos + count;
653
654 return count;
655}
656
Linus Torvalds1da177e2005-04-16 15:20:36 -0700657/*
658 * Transaction based IO.
659 * The file expects a single write which triggers the transaction, and then
660 * possibly a read which collects the result - which is stored in a
661 * file-local buffer.
662 */
Ingo Molnar76791ab2009-03-25 16:48:35 +0100663
664void simple_transaction_set(struct file *file, size_t n)
665{
666 struct simple_transaction_argresp *ar = file->private_data;
667
668 BUG_ON(n > SIMPLE_TRANSACTION_LIMIT);
669
670 /*
671 * The barrier ensures that ar->size will really remain zero until
672 * ar->data is ready for reading.
673 */
674 smp_mb();
675 ar->size = n;
676}
677
Linus Torvalds1da177e2005-04-16 15:20:36 -0700678char *simple_transaction_get(struct file *file, const char __user *buf, size_t size)
679{
680 struct simple_transaction_argresp *ar;
681 static DEFINE_SPINLOCK(simple_transaction_lock);
682
683 if (size > SIMPLE_TRANSACTION_LIMIT - 1)
684 return ERR_PTR(-EFBIG);
685
686 ar = (struct simple_transaction_argresp *)get_zeroed_page(GFP_KERNEL);
687 if (!ar)
688 return ERR_PTR(-ENOMEM);
689
690 spin_lock(&simple_transaction_lock);
691
692 /* only one write allowed per open */
693 if (file->private_data) {
694 spin_unlock(&simple_transaction_lock);
695 free_page((unsigned long)ar);
696 return ERR_PTR(-EBUSY);
697 }
698
699 file->private_data = ar;
700
701 spin_unlock(&simple_transaction_lock);
702
703 if (copy_from_user(ar->data, buf, size))
704 return ERR_PTR(-EFAULT);
705
706 return ar->data;
707}
708
709ssize_t simple_transaction_read(struct file *file, char __user *buf, size_t size, loff_t *pos)
710{
711 struct simple_transaction_argresp *ar = file->private_data;
712
713 if (!ar)
714 return 0;
715 return simple_read_from_buffer(buf, size, pos, ar->data, ar->size);
716}
717
718int simple_transaction_release(struct inode *inode, struct file *file)
719{
720 free_page((unsigned long)file->private_data);
721 return 0;
722}
723
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200724/* Simple attribute files */
725
726struct simple_attr {
Christoph Hellwig8b88b092008-02-08 04:20:26 -0800727 int (*get)(void *, u64 *);
728 int (*set)(void *, u64);
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200729 char get_buf[24]; /* enough to store a u64 and "\n\0" */
730 char set_buf[24];
731 void *data;
732 const char *fmt; /* format for read operation */
Ingo Molnar7cf34c72006-03-23 03:00:36 -0800733 struct mutex mutex; /* protects access to these buffers */
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200734};
735
736/* simple_attr_open is called by an actual attribute open file operation
737 * to set the attribute specific access operations. */
738int simple_attr_open(struct inode *inode, struct file *file,
Christoph Hellwig8b88b092008-02-08 04:20:26 -0800739 int (*get)(void *, u64 *), int (*set)(void *, u64),
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200740 const char *fmt)
741{
742 struct simple_attr *attr;
743
744 attr = kmalloc(sizeof(*attr), GFP_KERNEL);
745 if (!attr)
746 return -ENOMEM;
747
748 attr->get = get;
749 attr->set = set;
Theodore Ts'o8e18e292006-09-27 01:50:46 -0700750 attr->data = inode->i_private;
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200751 attr->fmt = fmt;
Ingo Molnar7cf34c72006-03-23 03:00:36 -0800752 mutex_init(&attr->mutex);
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200753
754 file->private_data = attr;
755
756 return nonseekable_open(inode, file);
757}
758
Christoph Hellwig74bedc42008-02-08 04:20:28 -0800759int simple_attr_release(struct inode *inode, struct file *file)
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200760{
761 kfree(file->private_data);
762 return 0;
763}
764
765/* read from the buffer that is filled with the get function */
766ssize_t simple_attr_read(struct file *file, char __user *buf,
767 size_t len, loff_t *ppos)
768{
769 struct simple_attr *attr;
770 size_t size;
771 ssize_t ret;
772
773 attr = file->private_data;
774
775 if (!attr->get)
776 return -EACCES;
777
Christoph Hellwig92613032008-02-08 04:20:27 -0800778 ret = mutex_lock_interruptible(&attr->mutex);
779 if (ret)
780 return ret;
781
Christoph Hellwig8b88b092008-02-08 04:20:26 -0800782 if (*ppos) { /* continued read */
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200783 size = strlen(attr->get_buf);
Christoph Hellwig8b88b092008-02-08 04:20:26 -0800784 } else { /* first read */
785 u64 val;
786 ret = attr->get(attr->data, &val);
787 if (ret)
788 goto out;
789
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200790 size = scnprintf(attr->get_buf, sizeof(attr->get_buf),
Christoph Hellwig8b88b092008-02-08 04:20:26 -0800791 attr->fmt, (unsigned long long)val);
792 }
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200793
794 ret = simple_read_from_buffer(buf, len, ppos, attr->get_buf, size);
Christoph Hellwig8b88b092008-02-08 04:20:26 -0800795out:
Ingo Molnar7cf34c72006-03-23 03:00:36 -0800796 mutex_unlock(&attr->mutex);
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200797 return ret;
798}
799
800/* interpret the buffer as a number to call the set function with */
801ssize_t simple_attr_write(struct file *file, const char __user *buf,
802 size_t len, loff_t *ppos)
803{
804 struct simple_attr *attr;
805 u64 val;
806 size_t size;
807 ssize_t ret;
808
809 attr = file->private_data;
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200810 if (!attr->set)
811 return -EACCES;
812
Christoph Hellwig92613032008-02-08 04:20:27 -0800813 ret = mutex_lock_interruptible(&attr->mutex);
814 if (ret)
815 return ret;
816
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200817 ret = -EFAULT;
818 size = min(sizeof(attr->set_buf) - 1, len);
819 if (copy_from_user(attr->set_buf, buf, size))
820 goto out;
821
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200822 attr->set_buf[size] = '\0';
823 val = simple_strtol(attr->set_buf, NULL, 0);
Wu Fengguang05cc0ce2009-09-18 13:06:03 -0700824 ret = attr->set(attr->data, val);
825 if (ret == 0)
826 ret = len; /* on success, claim we got the whole input */
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200827out:
Ingo Molnar7cf34c72006-03-23 03:00:36 -0800828 mutex_unlock(&attr->mutex);
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200829 return ret;
830}
831
Christoph Hellwig25961102007-10-21 16:42:05 -0700832/**
833 * generic_fh_to_dentry - generic helper for the fh_to_dentry export operation
834 * @sb: filesystem to do the file handle conversion on
835 * @fid: file handle to convert
836 * @fh_len: length of the file handle in bytes
837 * @fh_type: type of file handle
838 * @get_inode: filesystem callback to retrieve inode
839 *
840 * This function decodes @fid as long as it has one of the well-known
841 * Linux filehandle types and calls @get_inode on it to retrieve the
842 * inode for the object specified in the file handle.
843 */
844struct dentry *generic_fh_to_dentry(struct super_block *sb, struct fid *fid,
845 int fh_len, int fh_type, struct inode *(*get_inode)
846 (struct super_block *sb, u64 ino, u32 gen))
847{
848 struct inode *inode = NULL;
849
850 if (fh_len < 2)
851 return NULL;
852
853 switch (fh_type) {
854 case FILEID_INO32_GEN:
855 case FILEID_INO32_GEN_PARENT:
856 inode = get_inode(sb, fid->i32.ino, fid->i32.gen);
857 break;
858 }
859
Christoph Hellwig4ea3ada2008-08-11 15:48:57 +0200860 return d_obtain_alias(inode);
Christoph Hellwig25961102007-10-21 16:42:05 -0700861}
862EXPORT_SYMBOL_GPL(generic_fh_to_dentry);
863
864/**
865 * generic_fh_to_dentry - generic helper for the fh_to_parent export operation
866 * @sb: filesystem to do the file handle conversion on
867 * @fid: file handle to convert
868 * @fh_len: length of the file handle in bytes
869 * @fh_type: type of file handle
870 * @get_inode: filesystem callback to retrieve inode
871 *
872 * This function decodes @fid as long as it has one of the well-known
873 * Linux filehandle types and calls @get_inode on it to retrieve the
874 * inode for the _parent_ object specified in the file handle if it
875 * is specified in the file handle, or NULL otherwise.
876 */
877struct dentry *generic_fh_to_parent(struct super_block *sb, struct fid *fid,
878 int fh_len, int fh_type, struct inode *(*get_inode)
879 (struct super_block *sb, u64 ino, u32 gen))
880{
881 struct inode *inode = NULL;
882
883 if (fh_len <= 2)
884 return NULL;
885
886 switch (fh_type) {
887 case FILEID_INO32_GEN_PARENT:
888 inode = get_inode(sb, fid->i32.parent_ino,
889 (fh_len > 3 ? fid->i32.parent_gen : 0));
890 break;
891 }
892
Christoph Hellwig4ea3ada2008-08-11 15:48:57 +0200893 return d_obtain_alias(inode);
Christoph Hellwig25961102007-10-21 16:42:05 -0700894}
895EXPORT_SYMBOL_GPL(generic_fh_to_parent);
896
Christoph Hellwig1b061d92010-05-26 17:53:41 +0200897/**
898 * generic_file_fsync - generic fsync implementation for simple filesystems
899 * @file: file to synchronize
900 * @datasync: only synchronize essential metadata if true
901 *
902 * This is a generic implementation of the fsync method for simple
903 * filesystems which track all non-inode metadata in the buffers list
904 * hanging off the address_space structure.
905 */
906int generic_file_fsync(struct file *file, int datasync)
Al Virod5aacad2009-06-07 14:56:44 -0400907{
Christoph Hellwig7ea80852010-05-26 17:53:25 +0200908 struct inode *inode = file->f_mapping->host;
Al Virod5aacad2009-06-07 14:56:44 -0400909 int err;
910 int ret;
911
912 ret = sync_mapping_buffers(inode->i_mapping);
913 if (!(inode->i_state & I_DIRTY))
914 return ret;
915 if (datasync && !(inode->i_state & I_DIRTY_DATASYNC))
916 return ret;
917
Christoph Hellwigc37650162010-10-06 10:48:20 +0200918 err = sync_inode_metadata(inode, 1);
Al Virod5aacad2009-06-07 14:56:44 -0400919 if (ret == 0)
920 ret = err;
921 return ret;
922}
Christoph Hellwig1b061d92010-05-26 17:53:41 +0200923EXPORT_SYMBOL(generic_file_fsync);
924
Patrick J. LoPresti30ca22c2010-07-22 15:03:41 -0700925/**
926 * generic_check_addressable - Check addressability of file system
927 * @blocksize_bits: log of file system block size
928 * @num_blocks: number of blocks in file system
929 *
930 * Determine whether a file system with @num_blocks blocks (and a
931 * block size of 2**@blocksize_bits) is addressable by the sector_t
932 * and page cache of the system. Return 0 if so and -EFBIG otherwise.
933 */
934int generic_check_addressable(unsigned blocksize_bits, u64 num_blocks)
935{
936 u64 last_fs_block = num_blocks - 1;
Joel Beckera33f13e2010-08-16 12:10:17 -0700937 u64 last_fs_page =
938 last_fs_block >> (PAGE_CACHE_SHIFT - blocksize_bits);
Patrick J. LoPresti30ca22c2010-07-22 15:03:41 -0700939
940 if (unlikely(num_blocks == 0))
941 return 0;
942
943 if ((blocksize_bits < 9) || (blocksize_bits > PAGE_CACHE_SHIFT))
944 return -EINVAL;
945
Joel Beckera33f13e2010-08-16 12:10:17 -0700946 if ((last_fs_block > (sector_t)(~0ULL) >> (blocksize_bits - 9)) ||
947 (last_fs_page > (pgoff_t)(~0ULL))) {
Patrick J. LoPresti30ca22c2010-07-22 15:03:41 -0700948 return -EFBIG;
949 }
950 return 0;
951}
952EXPORT_SYMBOL(generic_check_addressable);
953
Christoph Hellwig1b061d92010-05-26 17:53:41 +0200954/*
955 * No-op implementation of ->fsync for in-memory filesystems.
956 */
957int noop_fsync(struct file *file, int datasync)
958{
959 return 0;
960}
Al Virod5aacad2009-06-07 14:56:44 -0400961
Linus Torvalds1da177e2005-04-16 15:20:36 -0700962EXPORT_SYMBOL(dcache_dir_close);
963EXPORT_SYMBOL(dcache_dir_lseek);
964EXPORT_SYMBOL(dcache_dir_open);
965EXPORT_SYMBOL(dcache_readdir);
966EXPORT_SYMBOL(generic_read_dir);
Al Viro51139ad2010-07-25 23:47:46 +0400967EXPORT_SYMBOL(mount_pseudo);
Nick Pigginafddba42007-10-16 01:25:01 -0700968EXPORT_SYMBOL(simple_write_begin);
969EXPORT_SYMBOL(simple_write_end);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700970EXPORT_SYMBOL(simple_dir_inode_operations);
971EXPORT_SYMBOL(simple_dir_operations);
972EXPORT_SYMBOL(simple_empty);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700973EXPORT_SYMBOL(simple_fill_super);
974EXPORT_SYMBOL(simple_getattr);
975EXPORT_SYMBOL(simple_link);
976EXPORT_SYMBOL(simple_lookup);
977EXPORT_SYMBOL(simple_pin_fs);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700978EXPORT_SYMBOL(simple_readpage);
979EXPORT_SYMBOL(simple_release_fs);
980EXPORT_SYMBOL(simple_rename);
981EXPORT_SYMBOL(simple_rmdir);
982EXPORT_SYMBOL(simple_statfs);
Christoph Hellwig1b061d92010-05-26 17:53:41 +0200983EXPORT_SYMBOL(noop_fsync);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700984EXPORT_SYMBOL(simple_unlink);
985EXPORT_SYMBOL(simple_read_from_buffer);
Jiri Slaby6a727b42010-05-01 23:51:22 +0200986EXPORT_SYMBOL(simple_write_to_buffer);
Akinobu Mita93b07112008-06-05 22:46:21 -0700987EXPORT_SYMBOL(memory_read_from_buffer);
Ingo Molnar76791ab2009-03-25 16:48:35 +0100988EXPORT_SYMBOL(simple_transaction_set);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700989EXPORT_SYMBOL(simple_transaction_get);
990EXPORT_SYMBOL(simple_transaction_read);
991EXPORT_SYMBOL(simple_transaction_release);
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200992EXPORT_SYMBOL_GPL(simple_attr_open);
Christoph Hellwig74bedc42008-02-08 04:20:28 -0800993EXPORT_SYMBOL_GPL(simple_attr_release);
Arnd Bergmannacaefc22005-05-18 14:40:59 +0200994EXPORT_SYMBOL_GPL(simple_attr_read);
995EXPORT_SYMBOL_GPL(simple_attr_write);