Commit | Line | Data |
---|---|---|
1da177e4 LT |
1 | /* |
2 | * fs/libfs.c | |
3 | * Library for filesystems writers. | |
4 | */ | |
5 | ||
ac13a829 | 6 | #include <linux/blkdev.h> |
630d9c47 | 7 | #include <linux/export.h> |
1da177e4 | 8 | #include <linux/pagemap.h> |
5a0e3ad6 | 9 | #include <linux/slab.h> |
1da177e4 LT |
10 | #include <linux/mount.h> |
11 | #include <linux/vfs.h> | |
7bb46a67 | 12 | #include <linux/quotaops.h> |
7cf34c76 | 13 | #include <linux/mutex.h> |
87dc800b | 14 | #include <linux/namei.h> |
2596110a | 15 | #include <linux/exportfs.h> |
d5aacad5 | 16 | #include <linux/writeback.h> |
ff01bb48 | 17 | #include <linux/buffer_head.h> /* sync_mapping_buffers */ |
7cf34c76 | 18 | |
1da177e4 LT |
19 | #include <asm/uaccess.h> |
20 | ||
a4464dbc AV |
21 | #include "internal.h" |
22 | ||
1da177e4 LT |
23 | int simple_getattr(struct vfsmount *mnt, struct dentry *dentry, |
24 | struct kstat *stat) | |
25 | { | |
dea655c2 | 26 | struct inode *inode = d_inode(dentry); |
1da177e4 | 27 | generic_fillattr(inode, stat); |
09cbfeaf | 28 | stat->blocks = inode->i_mapping->nrpages << (PAGE_SHIFT - 9); |
1da177e4 LT |
29 | return 0; |
30 | } | |
12f38872 | 31 | EXPORT_SYMBOL(simple_getattr); |
1da177e4 | 32 | |
726c3342 | 33 | int simple_statfs(struct dentry *dentry, struct kstatfs *buf) |
1da177e4 | 34 | { |
726c3342 | 35 | buf->f_type = dentry->d_sb->s_magic; |
09cbfeaf | 36 | buf->f_bsize = PAGE_SIZE; |
1da177e4 LT |
37 | buf->f_namelen = NAME_MAX; |
38 | return 0; | |
39 | } | |
12f38872 | 40 | EXPORT_SYMBOL(simple_statfs); |
1da177e4 LT |
41 | |
42 | /* | |
43 | * Retaining negative dentries for an in-memory filesystem just wastes | |
44 | * memory and lookup time: arrange for them to be deleted immediately. | |
45 | */ | |
b26d4cd3 | 46 | int always_delete_dentry(const struct dentry *dentry) |
1da177e4 LT |
47 | { |
48 | return 1; | |
49 | } | |
b26d4cd3 AV |
50 | EXPORT_SYMBOL(always_delete_dentry); |
51 | ||
52 | const struct dentry_operations simple_dentry_operations = { | |
53 | .d_delete = always_delete_dentry, | |
54 | }; | |
55 | EXPORT_SYMBOL(simple_dentry_operations); | |
1da177e4 LT |
56 | |
57 | /* | |
58 | * Lookup the data. This is trivial - if the dentry didn't already | |
59 | * exist, we know it is negative. Set d_op to delete negative dentries. | |
60 | */ | |
00cd8dd3 | 61 | struct dentry *simple_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags) |
1da177e4 | 62 | { |
1da177e4 LT |
63 | if (dentry->d_name.len > NAME_MAX) |
64 | return ERR_PTR(-ENAMETOOLONG); | |
74931da7 AV |
65 | if (!dentry->d_sb->s_d_op) |
66 | d_set_d_op(dentry, &simple_dentry_operations); | |
1da177e4 LT |
67 | d_add(dentry, NULL); |
68 | return NULL; | |
69 | } | |
12f38872 | 70 | EXPORT_SYMBOL(simple_lookup); |
1da177e4 | 71 | |
1da177e4 LT |
72 | int dcache_dir_open(struct inode *inode, struct file *file) |
73 | { | |
ba65dc5e | 74 | file->private_data = d_alloc_cursor(file->f_path.dentry); |
1da177e4 LT |
75 | |
76 | return file->private_data ? 0 : -ENOMEM; | |
77 | } | |
12f38872 | 78 | EXPORT_SYMBOL(dcache_dir_open); |
1da177e4 LT |
79 | |
80 | int dcache_dir_close(struct inode *inode, struct file *file) | |
81 | { | |
82 | dput(file->private_data); | |
83 | return 0; | |
84 | } | |
12f38872 | 85 | EXPORT_SYMBOL(dcache_dir_close); |
1da177e4 | 86 | |
4f42c1b5 AV |
87 | /* parent is locked at least shared */ |
88 | static struct dentry *next_positive(struct dentry *parent, | |
89 | struct list_head *from, | |
90 | int count) | |
91 | { | |
92 | struct dentry *res = NULL; | |
93 | struct list_head *p; | |
94 | ||
95 | spin_lock(&parent->d_lock); | |
96 | for (p = from->next; p != &parent->d_subdirs; p = p->next) { | |
97 | struct dentry *d = list_entry(p, struct dentry, d_child); | |
98 | if (simple_positive(d) && !--count) { | |
99 | res = d; | |
100 | break; | |
101 | } | |
102 | } | |
103 | spin_unlock(&parent->d_lock); | |
104 | return res; | |
105 | } | |
106 | ||
107 | static void move_cursor(struct dentry *cursor, struct list_head *after) | |
108 | { | |
109 | struct dentry *parent = cursor->d_parent; | |
110 | ||
111 | spin_lock(&parent->d_lock); | |
112 | __list_del(cursor->d_child.prev, cursor->d_child.next); | |
113 | if (after) | |
114 | list_add(&cursor->d_child, after); | |
115 | else | |
116 | list_add_tail(&cursor->d_child, &parent->d_subdirs); | |
117 | spin_unlock(&parent->d_lock); | |
118 | } | |
119 | ||
965c8e59 | 120 | loff_t dcache_dir_lseek(struct file *file, loff_t offset, int whence) |
1da177e4 | 121 | { |
2fd6b7f5 | 122 | struct dentry *dentry = file->f_path.dentry; |
965c8e59 | 123 | switch (whence) { |
1da177e4 LT |
124 | case 1: |
125 | offset += file->f_pos; | |
126 | case 0: | |
127 | if (offset >= 0) | |
128 | break; | |
129 | default: | |
1da177e4 LT |
130 | return -EINVAL; |
131 | } | |
132 | if (offset != file->f_pos) { | |
133 | file->f_pos = offset; | |
134 | if (file->f_pos >= 2) { | |
1da177e4 | 135 | struct dentry *cursor = file->private_data; |
4f42c1b5 | 136 | struct dentry *to; |
1da177e4 LT |
137 | loff_t n = file->f_pos - 2; |
138 | ||
274f5b04 | 139 | inode_lock_shared(dentry->d_inode); |
4f42c1b5 AV |
140 | to = next_positive(dentry, &dentry->d_subdirs, n); |
141 | move_cursor(cursor, to ? &to->d_child : NULL); | |
274f5b04 | 142 | inode_unlock_shared(dentry->d_inode); |
1da177e4 LT |
143 | } |
144 | } | |
1da177e4 LT |
145 | return offset; |
146 | } | |
12f38872 | 147 | EXPORT_SYMBOL(dcache_dir_lseek); |
1da177e4 LT |
148 | |
149 | /* Relationship between i_mode and the DT_xxx types */ | |
150 | static inline unsigned char dt_type(struct inode *inode) | |
151 | { | |
152 | return (inode->i_mode >> 12) & 15; | |
153 | } | |
154 | ||
155 | /* | |
156 | * Directory is locked and all positive dentries in it are safe, since | |
157 | * for ramfs-type trees they can't go away without unlink() or rmdir(), | |
158 | * both impossible due to the lock on directory. | |
159 | */ | |
160 | ||
5f99f4e7 | 161 | int dcache_readdir(struct file *file, struct dir_context *ctx) |
1da177e4 | 162 | { |
5f99f4e7 AV |
163 | struct dentry *dentry = file->f_path.dentry; |
164 | struct dentry *cursor = file->private_data; | |
4f42c1b5 AV |
165 | struct list_head *p = &cursor->d_child; |
166 | struct dentry *next; | |
167 | bool moved = false; | |
1da177e4 | 168 | |
5f99f4e7 AV |
169 | if (!dir_emit_dots(file, ctx)) |
170 | return 0; | |
5f99f4e7 | 171 | |
4f42c1b5 AV |
172 | if (ctx->pos == 2) |
173 | p = &dentry->d_subdirs; | |
174 | while ((next = next_positive(dentry, p, 1)) != NULL) { | |
5f99f4e7 | 175 | if (!dir_emit(ctx, next->d_name.name, next->d_name.len, |
dea655c2 | 176 | d_inode(next)->i_ino, dt_type(d_inode(next)))) |
4f42c1b5 AV |
177 | break; |
178 | moved = true; | |
179 | p = &next->d_child; | |
5f99f4e7 | 180 | ctx->pos++; |
1da177e4 | 181 | } |
4f42c1b5 AV |
182 | if (moved) |
183 | move_cursor(cursor, p); | |
1da177e4 LT |
184 | return 0; |
185 | } | |
12f38872 | 186 | EXPORT_SYMBOL(dcache_readdir); |
1da177e4 LT |
187 | |
188 | ssize_t generic_read_dir(struct file *filp, char __user *buf, size_t siz, loff_t *ppos) | |
189 | { | |
190 | return -EISDIR; | |
191 | } | |
12f38872 | 192 | EXPORT_SYMBOL(generic_read_dir); |
1da177e4 | 193 | |
4b6f5d20 | 194 | const struct file_operations simple_dir_operations = { |
1da177e4 LT |
195 | .open = dcache_dir_open, |
196 | .release = dcache_dir_close, | |
197 | .llseek = dcache_dir_lseek, | |
198 | .read = generic_read_dir, | |
4e82901c | 199 | .iterate_shared = dcache_readdir, |
1b061d92 | 200 | .fsync = noop_fsync, |
1da177e4 | 201 | }; |
12f38872 | 202 | EXPORT_SYMBOL(simple_dir_operations); |
1da177e4 | 203 | |
92e1d5be | 204 | const struct inode_operations simple_dir_inode_operations = { |
1da177e4 LT |
205 | .lookup = simple_lookup, |
206 | }; | |
12f38872 | 207 | EXPORT_SYMBOL(simple_dir_inode_operations); |
1da177e4 | 208 | |
759b9775 HD |
209 | static const struct super_operations simple_super_operations = { |
210 | .statfs = simple_statfs, | |
211 | }; | |
212 | ||
1da177e4 LT |
213 | /* |
214 | * Common helper for pseudo-filesystems (sockfs, pipefs, bdev - stuff that | |
215 | * will never be mountable) | |
216 | */ | |
51139ada | 217 | struct dentry *mount_pseudo(struct file_system_type *fs_type, char *name, |
c74a1cbb AV |
218 | const struct super_operations *ops, |
219 | const struct dentry_operations *dops, unsigned long magic) | |
1da177e4 | 220 | { |
9249e17f | 221 | struct super_block *s; |
1da177e4 LT |
222 | struct dentry *dentry; |
223 | struct inode *root; | |
26fe5750 | 224 | struct qstr d_name = QSTR_INIT(name, strlen(name)); |
1da177e4 | 225 | |
9249e17f | 226 | s = sget(fs_type, NULL, set_anon_super, MS_NOUSER, NULL); |
1da177e4 | 227 | if (IS_ERR(s)) |
51139ada | 228 | return ERR_CAST(s); |
1da177e4 | 229 | |
89a4eb4b | 230 | s->s_maxbytes = MAX_LFS_FILESIZE; |
3971e1a9 AN |
231 | s->s_blocksize = PAGE_SIZE; |
232 | s->s_blocksize_bits = PAGE_SHIFT; | |
1da177e4 | 233 | s->s_magic = magic; |
759b9775 | 234 | s->s_op = ops ? ops : &simple_super_operations; |
1da177e4 LT |
235 | s->s_time_gran = 1; |
236 | root = new_inode(s); | |
237 | if (!root) | |
238 | goto Enomem; | |
1a1c9bb4 JL |
239 | /* |
240 | * since this is the first inode, make it number 1. New inodes created | |
241 | * after this must take care not to collide with it (by passing | |
242 | * max_reserved of 1 to iunique). | |
243 | */ | |
244 | root->i_ino = 1; | |
1da177e4 | 245 | root->i_mode = S_IFDIR | S_IRUSR | S_IWUSR; |
1da177e4 | 246 | root->i_atime = root->i_mtime = root->i_ctime = CURRENT_TIME; |
a4464dbc | 247 | dentry = __d_alloc(s, &d_name); |
1da177e4 LT |
248 | if (!dentry) { |
249 | iput(root); | |
250 | goto Enomem; | |
251 | } | |
1da177e4 LT |
252 | d_instantiate(dentry, root); |
253 | s->s_root = dentry; | |
c74a1cbb | 254 | s->s_d_op = dops; |
1da177e4 | 255 | s->s_flags |= MS_ACTIVE; |
51139ada | 256 | return dget(s->s_root); |
1da177e4 LT |
257 | |
258 | Enomem: | |
6f5bbff9 | 259 | deactivate_locked_super(s); |
51139ada | 260 | return ERR_PTR(-ENOMEM); |
1da177e4 | 261 | } |
12f38872 | 262 | EXPORT_SYMBOL(mount_pseudo); |
1da177e4 | 263 | |
20955e89 SB |
264 | int simple_open(struct inode *inode, struct file *file) |
265 | { | |
266 | if (inode->i_private) | |
267 | file->private_data = inode->i_private; | |
268 | return 0; | |
269 | } | |
12f38872 | 270 | EXPORT_SYMBOL(simple_open); |
20955e89 | 271 | |
1da177e4 LT |
272 | int simple_link(struct dentry *old_dentry, struct inode *dir, struct dentry *dentry) |
273 | { | |
dea655c2 | 274 | struct inode *inode = d_inode(old_dentry); |
1da177e4 LT |
275 | |
276 | inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME; | |
d8c76e6f | 277 | inc_nlink(inode); |
7de9c6ee | 278 | ihold(inode); |
1da177e4 LT |
279 | dget(dentry); |
280 | d_instantiate(dentry, inode); | |
281 | return 0; | |
282 | } | |
12f38872 | 283 | EXPORT_SYMBOL(simple_link); |
1da177e4 | 284 | |
1da177e4 LT |
285 | int simple_empty(struct dentry *dentry) |
286 | { | |
287 | struct dentry *child; | |
288 | int ret = 0; | |
289 | ||
2fd6b7f5 | 290 | spin_lock(&dentry->d_lock); |
946e51f2 | 291 | list_for_each_entry(child, &dentry->d_subdirs, d_child) { |
da502956 NP |
292 | spin_lock_nested(&child->d_lock, DENTRY_D_LOCK_NESTED); |
293 | if (simple_positive(child)) { | |
294 | spin_unlock(&child->d_lock); | |
1da177e4 | 295 | goto out; |
da502956 NP |
296 | } |
297 | spin_unlock(&child->d_lock); | |
298 | } | |
1da177e4 LT |
299 | ret = 1; |
300 | out: | |
2fd6b7f5 | 301 | spin_unlock(&dentry->d_lock); |
1da177e4 LT |
302 | return ret; |
303 | } | |
12f38872 | 304 | EXPORT_SYMBOL(simple_empty); |
1da177e4 LT |
305 | |
306 | int simple_unlink(struct inode *dir, struct dentry *dentry) | |
307 | { | |
dea655c2 | 308 | struct inode *inode = d_inode(dentry); |
1da177e4 LT |
309 | |
310 | inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME; | |
9a53c3a7 | 311 | drop_nlink(inode); |
1da177e4 LT |
312 | dput(dentry); |
313 | return 0; | |
314 | } | |
12f38872 | 315 | EXPORT_SYMBOL(simple_unlink); |
1da177e4 LT |
316 | |
317 | int simple_rmdir(struct inode *dir, struct dentry *dentry) | |
318 | { | |
319 | if (!simple_empty(dentry)) | |
320 | return -ENOTEMPTY; | |
321 | ||
dea655c2 | 322 | drop_nlink(d_inode(dentry)); |
1da177e4 | 323 | simple_unlink(dir, dentry); |
9a53c3a7 | 324 | drop_nlink(dir); |
1da177e4 LT |
325 | return 0; |
326 | } | |
12f38872 | 327 | EXPORT_SYMBOL(simple_rmdir); |
1da177e4 LT |
328 | |
329 | int simple_rename(struct inode *old_dir, struct dentry *old_dentry, | |
330 | struct inode *new_dir, struct dentry *new_dentry) | |
331 | { | |
dea655c2 | 332 | struct inode *inode = d_inode(old_dentry); |
e36cb0b8 | 333 | int they_are_dirs = d_is_dir(old_dentry); |
1da177e4 LT |
334 | |
335 | if (!simple_empty(new_dentry)) | |
336 | return -ENOTEMPTY; | |
337 | ||
dea655c2 | 338 | if (d_really_is_positive(new_dentry)) { |
1da177e4 | 339 | simple_unlink(new_dir, new_dentry); |
841590ce | 340 | if (they_are_dirs) { |
dea655c2 | 341 | drop_nlink(d_inode(new_dentry)); |
9a53c3a7 | 342 | drop_nlink(old_dir); |
841590ce | 343 | } |
1da177e4 | 344 | } else if (they_are_dirs) { |
9a53c3a7 | 345 | drop_nlink(old_dir); |
d8c76e6f | 346 | inc_nlink(new_dir); |
1da177e4 LT |
347 | } |
348 | ||
349 | old_dir->i_ctime = old_dir->i_mtime = new_dir->i_ctime = | |
350 | new_dir->i_mtime = inode->i_ctime = CURRENT_TIME; | |
351 | ||
352 | return 0; | |
353 | } | |
12f38872 | 354 | EXPORT_SYMBOL(simple_rename); |
1da177e4 | 355 | |
7bb46a67 | 356 | /** |
eef2380c | 357 | * simple_setattr - setattr for simple filesystem |
7bb46a67 | 358 | * @dentry: dentry |
359 | * @iattr: iattr structure | |
360 | * | |
361 | * Returns 0 on success, -error on failure. | |
362 | * | |
eef2380c CH |
363 | * simple_setattr is a simple ->setattr implementation without a proper |
364 | * implementation of size changes. | |
365 | * | |
366 | * It can either be used for in-memory filesystems or special files | |
367 | * on simple regular filesystems. Anything that needs to change on-disk | |
368 | * or wire state on size changes needs its own setattr method. | |
7bb46a67 | 369 | */ |
370 | int simple_setattr(struct dentry *dentry, struct iattr *iattr) | |
371 | { | |
dea655c2 | 372 | struct inode *inode = d_inode(dentry); |
7bb46a67 | 373 | int error; |
374 | ||
375 | error = inode_change_ok(inode, iattr); | |
376 | if (error) | |
377 | return error; | |
378 | ||
2c27c65e CH |
379 | if (iattr->ia_valid & ATTR_SIZE) |
380 | truncate_setsize(inode, iattr->ia_size); | |
6a1a90ad | 381 | setattr_copy(inode, iattr); |
eef2380c CH |
382 | mark_inode_dirty(inode); |
383 | return 0; | |
7bb46a67 | 384 | } |
385 | EXPORT_SYMBOL(simple_setattr); | |
386 | ||
1da177e4 LT |
387 | int simple_readpage(struct file *file, struct page *page) |
388 | { | |
c0d92cbc | 389 | clear_highpage(page); |
1da177e4 LT |
390 | flush_dcache_page(page); |
391 | SetPageUptodate(page); | |
1da177e4 LT |
392 | unlock_page(page); |
393 | return 0; | |
394 | } | |
12f38872 | 395 | EXPORT_SYMBOL(simple_readpage); |
1da177e4 | 396 | |
afddba49 NP |
397 | int simple_write_begin(struct file *file, struct address_space *mapping, |
398 | loff_t pos, unsigned len, unsigned flags, | |
399 | struct page **pagep, void **fsdata) | |
400 | { | |
401 | struct page *page; | |
402 | pgoff_t index; | |
afddba49 | 403 | |
09cbfeaf | 404 | index = pos >> PAGE_SHIFT; |
afddba49 | 405 | |
54566b2c | 406 | page = grab_cache_page_write_begin(mapping, index, flags); |
afddba49 NP |
407 | if (!page) |
408 | return -ENOMEM; | |
409 | ||
410 | *pagep = page; | |
411 | ||
09cbfeaf KS |
412 | if (!PageUptodate(page) && (len != PAGE_SIZE)) { |
413 | unsigned from = pos & (PAGE_SIZE - 1); | |
193cf4b9 | 414 | |
09cbfeaf | 415 | zero_user_segments(page, 0, from, from + len, PAGE_SIZE); |
193cf4b9 BH |
416 | } |
417 | return 0; | |
afddba49 | 418 | } |
12f38872 | 419 | EXPORT_SYMBOL(simple_write_begin); |
afddba49 | 420 | |
ad2a722f BH |
421 | /** |
422 | * simple_write_end - .write_end helper for non-block-device FSes | |
423 | * @available: See .write_end of address_space_operations | |
424 | * @file: " | |
425 | * @mapping: " | |
426 | * @pos: " | |
427 | * @len: " | |
428 | * @copied: " | |
429 | * @page: " | |
430 | * @fsdata: " | |
431 | * | |
432 | * simple_write_end does the minimum needed for updating a page after writing is | |
433 | * done. It has the same API signature as the .write_end of | |
434 | * address_space_operations vector. So it can just be set onto .write_end for | |
435 | * FSes that don't need any other processing. i_mutex is assumed to be held. | |
436 | * Block based filesystems should use generic_write_end(). | |
437 | * NOTE: Even though i_size might get updated by this function, mark_inode_dirty | |
438 | * is not called, so a filesystem that actually does store data in .write_inode | |
439 | * should extend on what's done here with a call to mark_inode_dirty() in the | |
440 | * case that i_size has changed. | |
441 | */ | |
afddba49 NP |
442 | int simple_write_end(struct file *file, struct address_space *mapping, |
443 | loff_t pos, unsigned len, unsigned copied, | |
444 | struct page *page, void *fsdata) | |
445 | { | |
ad2a722f BH |
446 | struct inode *inode = page->mapping->host; |
447 | loff_t last_pos = pos + copied; | |
afddba49 NP |
448 | |
449 | /* zero the stale part of the page if we did a short copy */ | |
450 | if (copied < len) { | |
09cbfeaf | 451 | unsigned from = pos & (PAGE_SIZE - 1); |
ad2a722f BH |
452 | |
453 | zero_user(page, from + copied, len - copied); | |
afddba49 NP |
454 | } |
455 | ||
ad2a722f BH |
456 | if (!PageUptodate(page)) |
457 | SetPageUptodate(page); | |
458 | /* | |
459 | * No need to use i_size_read() here, the i_size | |
460 | * cannot change under us because we hold the i_mutex. | |
461 | */ | |
462 | if (last_pos > inode->i_size) | |
463 | i_size_write(inode, last_pos); | |
afddba49 | 464 | |
ad2a722f | 465 | set_page_dirty(page); |
afddba49 | 466 | unlock_page(page); |
09cbfeaf | 467 | put_page(page); |
afddba49 NP |
468 | |
469 | return copied; | |
470 | } | |
12f38872 | 471 | EXPORT_SYMBOL(simple_write_end); |
afddba49 | 472 | |
1a1c9bb4 JL |
473 | /* |
474 | * the inodes created here are not hashed. If you use iunique to generate | |
475 | * unique inode values later for this filesystem, then you must take care | |
476 | * to pass it an appropriate max_reserved value to avoid collisions. | |
477 | */ | |
7d683a09 RS |
478 | int simple_fill_super(struct super_block *s, unsigned long magic, |
479 | struct tree_descr *files) | |
1da177e4 | 480 | { |
1da177e4 LT |
481 | struct inode *inode; |
482 | struct dentry *root; | |
483 | struct dentry *dentry; | |
484 | int i; | |
485 | ||
09cbfeaf KS |
486 | s->s_blocksize = PAGE_SIZE; |
487 | s->s_blocksize_bits = PAGE_SHIFT; | |
1da177e4 | 488 | s->s_magic = magic; |
759b9775 | 489 | s->s_op = &simple_super_operations; |
1da177e4 LT |
490 | s->s_time_gran = 1; |
491 | ||
492 | inode = new_inode(s); | |
493 | if (!inode) | |
494 | return -ENOMEM; | |
1a1c9bb4 JL |
495 | /* |
496 | * because the root inode is 1, the files array must not contain an | |
497 | * entry at index 1 | |
498 | */ | |
499 | inode->i_ino = 1; | |
1da177e4 | 500 | inode->i_mode = S_IFDIR | 0755; |
1da177e4 LT |
501 | inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; |
502 | inode->i_op = &simple_dir_inode_operations; | |
503 | inode->i_fop = &simple_dir_operations; | |
bfe86848 | 504 | set_nlink(inode, 2); |
48fde701 AV |
505 | root = d_make_root(inode); |
506 | if (!root) | |
1da177e4 | 507 | return -ENOMEM; |
1da177e4 LT |
508 | for (i = 0; !files->name || files->name[0]; i++, files++) { |
509 | if (!files->name) | |
510 | continue; | |
1a1c9bb4 JL |
511 | |
512 | /* warn if it tries to conflict with the root inode */ | |
513 | if (unlikely(i == 1)) | |
514 | printk(KERN_WARNING "%s: %s passed in a files array" | |
515 | "with an index of 1!\n", __func__, | |
516 | s->s_type->name); | |
517 | ||
1da177e4 LT |
518 | dentry = d_alloc_name(root, files->name); |
519 | if (!dentry) | |
520 | goto out; | |
521 | inode = new_inode(s); | |
32096ea1 KK |
522 | if (!inode) { |
523 | dput(dentry); | |
1da177e4 | 524 | goto out; |
32096ea1 | 525 | } |
1da177e4 | 526 | inode->i_mode = S_IFREG | files->mode; |
1da177e4 LT |
527 | inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; |
528 | inode->i_fop = files->ops; | |
529 | inode->i_ino = i; | |
530 | d_add(dentry, inode); | |
531 | } | |
532 | s->s_root = root; | |
533 | return 0; | |
534 | out: | |
535 | d_genocide(root); | |
640946f2 | 536 | shrink_dcache_parent(root); |
1da177e4 LT |
537 | dput(root); |
538 | return -ENOMEM; | |
539 | } | |
12f38872 | 540 | EXPORT_SYMBOL(simple_fill_super); |
1da177e4 LT |
541 | |
542 | static DEFINE_SPINLOCK(pin_fs_lock); | |
543 | ||
1f5ce9e9 | 544 | int simple_pin_fs(struct file_system_type *type, struct vfsmount **mount, int *count) |
1da177e4 LT |
545 | { |
546 | struct vfsmount *mnt = NULL; | |
547 | spin_lock(&pin_fs_lock); | |
548 | if (unlikely(!*mount)) { | |
549 | spin_unlock(&pin_fs_lock); | |
2452992a | 550 | mnt = vfs_kern_mount(type, MS_KERNMOUNT, type->name, NULL); |
1da177e4 LT |
551 | if (IS_ERR(mnt)) |
552 | return PTR_ERR(mnt); | |
553 | spin_lock(&pin_fs_lock); | |
554 | if (!*mount) | |
555 | *mount = mnt; | |
556 | } | |
557 | mntget(*mount); | |
558 | ++*count; | |
559 | spin_unlock(&pin_fs_lock); | |
560 | mntput(mnt); | |
561 | return 0; | |
562 | } | |
12f38872 | 563 | EXPORT_SYMBOL(simple_pin_fs); |
1da177e4 LT |
564 | |
565 | void simple_release_fs(struct vfsmount **mount, int *count) | |
566 | { | |
567 | struct vfsmount *mnt; | |
568 | spin_lock(&pin_fs_lock); | |
569 | mnt = *mount; | |
570 | if (!--*count) | |
571 | *mount = NULL; | |
572 | spin_unlock(&pin_fs_lock); | |
573 | mntput(mnt); | |
574 | } | |
12f38872 | 575 | EXPORT_SYMBOL(simple_release_fs); |
1da177e4 | 576 | |
6d1029b5 AM |
577 | /** |
578 | * simple_read_from_buffer - copy data from the buffer to user space | |
579 | * @to: the user space buffer to read to | |
580 | * @count: the maximum number of bytes to read | |
581 | * @ppos: the current position in the buffer | |
582 | * @from: the buffer to read from | |
583 | * @available: the size of the buffer | |
584 | * | |
585 | * The simple_read_from_buffer() function reads up to @count bytes from the | |
586 | * buffer @from at offset @ppos into the user space address starting at @to. | |
587 | * | |
588 | * On success, the number of bytes read is returned and the offset @ppos is | |
589 | * advanced by this number, or negative value is returned on error. | |
590 | **/ | |
1da177e4 LT |
591 | ssize_t simple_read_from_buffer(void __user *to, size_t count, loff_t *ppos, |
592 | const void *from, size_t available) | |
593 | { | |
594 | loff_t pos = *ppos; | |
14be2746 SR |
595 | size_t ret; |
596 | ||
1da177e4 LT |
597 | if (pos < 0) |
598 | return -EINVAL; | |
14be2746 | 599 | if (pos >= available || !count) |
1da177e4 LT |
600 | return 0; |
601 | if (count > available - pos) | |
602 | count = available - pos; | |
14be2746 SR |
603 | ret = copy_to_user(to, from + pos, count); |
604 | if (ret == count) | |
1da177e4 | 605 | return -EFAULT; |
14be2746 | 606 | count -= ret; |
1da177e4 LT |
607 | *ppos = pos + count; |
608 | return count; | |
609 | } | |
12f38872 | 610 | EXPORT_SYMBOL(simple_read_from_buffer); |
1da177e4 | 611 | |
6a727b43 JS |
612 | /** |
613 | * simple_write_to_buffer - copy data from user space to the buffer | |
614 | * @to: the buffer to write to | |
615 | * @available: the size of the buffer | |
616 | * @ppos: the current position in the buffer | |
617 | * @from: the user space buffer to read from | |
618 | * @count: the maximum number of bytes to read | |
619 | * | |
620 | * The simple_write_to_buffer() function reads up to @count bytes from the user | |
621 | * space address starting at @from into the buffer @to at offset @ppos. | |
622 | * | |
623 | * On success, the number of bytes written is returned and the offset @ppos is | |
624 | * advanced by this number, or negative value is returned on error. | |
625 | **/ | |
626 | ssize_t simple_write_to_buffer(void *to, size_t available, loff_t *ppos, | |
627 | const void __user *from, size_t count) | |
628 | { | |
629 | loff_t pos = *ppos; | |
630 | size_t res; | |
631 | ||
632 | if (pos < 0) | |
633 | return -EINVAL; | |
634 | if (pos >= available || !count) | |
635 | return 0; | |
636 | if (count > available - pos) | |
637 | count = available - pos; | |
638 | res = copy_from_user(to + pos, from, count); | |
639 | if (res == count) | |
640 | return -EFAULT; | |
641 | count -= res; | |
642 | *ppos = pos + count; | |
643 | return count; | |
644 | } | |
12f38872 | 645 | EXPORT_SYMBOL(simple_write_to_buffer); |
6a727b43 | 646 | |
6d1029b5 AM |
647 | /** |
648 | * memory_read_from_buffer - copy data from the buffer | |
649 | * @to: the kernel space buffer to read to | |
650 | * @count: the maximum number of bytes to read | |
651 | * @ppos: the current position in the buffer | |
652 | * @from: the buffer to read from | |
653 | * @available: the size of the buffer | |
654 | * | |
655 | * The memory_read_from_buffer() function reads up to @count bytes from the | |
656 | * buffer @from at offset @ppos into the kernel space address starting at @to. | |
657 | * | |
658 | * On success, the number of bytes read is returned and the offset @ppos is | |
659 | * advanced by this number, or negative value is returned on error. | |
660 | **/ | |
93b07113 AM |
661 | ssize_t memory_read_from_buffer(void *to, size_t count, loff_t *ppos, |
662 | const void *from, size_t available) | |
663 | { | |
664 | loff_t pos = *ppos; | |
665 | ||
666 | if (pos < 0) | |
667 | return -EINVAL; | |
668 | if (pos >= available) | |
669 | return 0; | |
670 | if (count > available - pos) | |
671 | count = available - pos; | |
672 | memcpy(to, from + pos, count); | |
673 | *ppos = pos + count; | |
674 | ||
675 | return count; | |
676 | } | |
12f38872 | 677 | EXPORT_SYMBOL(memory_read_from_buffer); |
93b07113 | 678 | |
1da177e4 LT |
679 | /* |
680 | * Transaction based IO. | |
681 | * The file expects a single write which triggers the transaction, and then | |
682 | * possibly a read which collects the result - which is stored in a | |
683 | * file-local buffer. | |
684 | */ | |
76791ab2 IM |
685 | |
686 | void simple_transaction_set(struct file *file, size_t n) | |
687 | { | |
688 | struct simple_transaction_argresp *ar = file->private_data; | |
689 | ||
690 | BUG_ON(n > SIMPLE_TRANSACTION_LIMIT); | |
691 | ||
692 | /* | |
693 | * The barrier ensures that ar->size will really remain zero until | |
694 | * ar->data is ready for reading. | |
695 | */ | |
696 | smp_mb(); | |
697 | ar->size = n; | |
698 | } | |
12f38872 | 699 | EXPORT_SYMBOL(simple_transaction_set); |
76791ab2 | 700 | |
1da177e4 LT |
701 | char *simple_transaction_get(struct file *file, const char __user *buf, size_t size) |
702 | { | |
703 | struct simple_transaction_argresp *ar; | |
704 | static DEFINE_SPINLOCK(simple_transaction_lock); | |
705 | ||
706 | if (size > SIMPLE_TRANSACTION_LIMIT - 1) | |
707 | return ERR_PTR(-EFBIG); | |
708 | ||
709 | ar = (struct simple_transaction_argresp *)get_zeroed_page(GFP_KERNEL); | |
710 | if (!ar) | |
711 | return ERR_PTR(-ENOMEM); | |
712 | ||
713 | spin_lock(&simple_transaction_lock); | |
714 | ||
715 | /* only one write allowed per open */ | |
716 | if (file->private_data) { | |
717 | spin_unlock(&simple_transaction_lock); | |
718 | free_page((unsigned long)ar); | |
719 | return ERR_PTR(-EBUSY); | |
720 | } | |
721 | ||
722 | file->private_data = ar; | |
723 | ||
724 | spin_unlock(&simple_transaction_lock); | |
725 | ||
726 | if (copy_from_user(ar->data, buf, size)) | |
727 | return ERR_PTR(-EFAULT); | |
728 | ||
729 | return ar->data; | |
730 | } | |
12f38872 | 731 | EXPORT_SYMBOL(simple_transaction_get); |
1da177e4 LT |
732 | |
733 | ssize_t simple_transaction_read(struct file *file, char __user *buf, size_t size, loff_t *pos) | |
734 | { | |
735 | struct simple_transaction_argresp *ar = file->private_data; | |
736 | ||
737 | if (!ar) | |
738 | return 0; | |
739 | return simple_read_from_buffer(buf, size, pos, ar->data, ar->size); | |
740 | } | |
12f38872 | 741 | EXPORT_SYMBOL(simple_transaction_read); |
1da177e4 LT |
742 | |
743 | int simple_transaction_release(struct inode *inode, struct file *file) | |
744 | { | |
745 | free_page((unsigned long)file->private_data); | |
746 | return 0; | |
747 | } | |
12f38872 | 748 | EXPORT_SYMBOL(simple_transaction_release); |
1da177e4 | 749 | |
acaefc25 AB |
750 | /* Simple attribute files */ |
751 | ||
752 | struct simple_attr { | |
8b88b099 CH |
753 | int (*get)(void *, u64 *); |
754 | int (*set)(void *, u64); | |
acaefc25 AB |
755 | char get_buf[24]; /* enough to store a u64 and "\n\0" */ |
756 | char set_buf[24]; | |
757 | void *data; | |
758 | const char *fmt; /* format for read operation */ | |
7cf34c76 | 759 | struct mutex mutex; /* protects access to these buffers */ |
acaefc25 AB |
760 | }; |
761 | ||
762 | /* simple_attr_open is called by an actual attribute open file operation | |
763 | * to set the attribute specific access operations. */ | |
764 | int simple_attr_open(struct inode *inode, struct file *file, | |
8b88b099 | 765 | int (*get)(void *, u64 *), int (*set)(void *, u64), |
acaefc25 AB |
766 | const char *fmt) |
767 | { | |
768 | struct simple_attr *attr; | |
769 | ||
770 | attr = kmalloc(sizeof(*attr), GFP_KERNEL); | |
771 | if (!attr) | |
772 | return -ENOMEM; | |
773 | ||
774 | attr->get = get; | |
775 | attr->set = set; | |
8e18e294 | 776 | attr->data = inode->i_private; |
acaefc25 | 777 | attr->fmt = fmt; |
7cf34c76 | 778 | mutex_init(&attr->mutex); |
acaefc25 AB |
779 | |
780 | file->private_data = attr; | |
781 | ||
782 | return nonseekable_open(inode, file); | |
783 | } | |
12f38872 | 784 | EXPORT_SYMBOL_GPL(simple_attr_open); |
acaefc25 | 785 | |
74bedc4d | 786 | int simple_attr_release(struct inode *inode, struct file *file) |
acaefc25 AB |
787 | { |
788 | kfree(file->private_data); | |
789 | return 0; | |
790 | } | |
12f38872 | 791 | EXPORT_SYMBOL_GPL(simple_attr_release); /* GPL-only? This? Really? */ |
acaefc25 AB |
792 | |
793 | /* read from the buffer that is filled with the get function */ | |
794 | ssize_t simple_attr_read(struct file *file, char __user *buf, | |
795 | size_t len, loff_t *ppos) | |
796 | { | |
797 | struct simple_attr *attr; | |
798 | size_t size; | |
799 | ssize_t ret; | |
800 | ||
801 | attr = file->private_data; | |
802 | ||
803 | if (!attr->get) | |
804 | return -EACCES; | |
805 | ||
9261303a CH |
806 | ret = mutex_lock_interruptible(&attr->mutex); |
807 | if (ret) | |
808 | return ret; | |
809 | ||
8b88b099 | 810 | if (*ppos) { /* continued read */ |
acaefc25 | 811 | size = strlen(attr->get_buf); |
8b88b099 CH |
812 | } else { /* first read */ |
813 | u64 val; | |
814 | ret = attr->get(attr->data, &val); | |
815 | if (ret) | |
816 | goto out; | |
817 | ||
acaefc25 | 818 | size = scnprintf(attr->get_buf, sizeof(attr->get_buf), |
8b88b099 CH |
819 | attr->fmt, (unsigned long long)val); |
820 | } | |
acaefc25 AB |
821 | |
822 | ret = simple_read_from_buffer(buf, len, ppos, attr->get_buf, size); | |
8b88b099 | 823 | out: |
7cf34c76 | 824 | mutex_unlock(&attr->mutex); |
acaefc25 AB |
825 | return ret; |
826 | } | |
12f38872 | 827 | EXPORT_SYMBOL_GPL(simple_attr_read); |
acaefc25 AB |
828 | |
829 | /* interpret the buffer as a number to call the set function with */ | |
830 | ssize_t simple_attr_write(struct file *file, const char __user *buf, | |
831 | size_t len, loff_t *ppos) | |
832 | { | |
833 | struct simple_attr *attr; | |
834 | u64 val; | |
835 | size_t size; | |
836 | ssize_t ret; | |
837 | ||
838 | attr = file->private_data; | |
acaefc25 AB |
839 | if (!attr->set) |
840 | return -EACCES; | |
841 | ||
9261303a CH |
842 | ret = mutex_lock_interruptible(&attr->mutex); |
843 | if (ret) | |
844 | return ret; | |
845 | ||
acaefc25 AB |
846 | ret = -EFAULT; |
847 | size = min(sizeof(attr->set_buf) - 1, len); | |
848 | if (copy_from_user(attr->set_buf, buf, size)) | |
849 | goto out; | |
850 | ||
acaefc25 | 851 | attr->set_buf[size] = '\0'; |
f7b88631 | 852 | val = simple_strtoll(attr->set_buf, NULL, 0); |
05cc0cee WF |
853 | ret = attr->set(attr->data, val); |
854 | if (ret == 0) | |
855 | ret = len; /* on success, claim we got the whole input */ | |
acaefc25 | 856 | out: |
7cf34c76 | 857 | mutex_unlock(&attr->mutex); |
acaefc25 AB |
858 | return ret; |
859 | } | |
12f38872 | 860 | EXPORT_SYMBOL_GPL(simple_attr_write); |
acaefc25 | 861 | |
2596110a CH |
862 | /** |
863 | * generic_fh_to_dentry - generic helper for the fh_to_dentry export operation | |
864 | * @sb: filesystem to do the file handle conversion on | |
865 | * @fid: file handle to convert | |
866 | * @fh_len: length of the file handle in bytes | |
867 | * @fh_type: type of file handle | |
868 | * @get_inode: filesystem callback to retrieve inode | |
869 | * | |
870 | * This function decodes @fid as long as it has one of the well-known | |
871 | * Linux filehandle types and calls @get_inode on it to retrieve the | |
872 | * inode for the object specified in the file handle. | |
873 | */ | |
874 | struct dentry *generic_fh_to_dentry(struct super_block *sb, struct fid *fid, | |
875 | int fh_len, int fh_type, struct inode *(*get_inode) | |
876 | (struct super_block *sb, u64 ino, u32 gen)) | |
877 | { | |
878 | struct inode *inode = NULL; | |
879 | ||
880 | if (fh_len < 2) | |
881 | return NULL; | |
882 | ||
883 | switch (fh_type) { | |
884 | case FILEID_INO32_GEN: | |
885 | case FILEID_INO32_GEN_PARENT: | |
886 | inode = get_inode(sb, fid->i32.ino, fid->i32.gen); | |
887 | break; | |
888 | } | |
889 | ||
4ea3ada2 | 890 | return d_obtain_alias(inode); |
2596110a CH |
891 | } |
892 | EXPORT_SYMBOL_GPL(generic_fh_to_dentry); | |
893 | ||
894 | /** | |
ca186830 | 895 | * generic_fh_to_parent - generic helper for the fh_to_parent export operation |
2596110a CH |
896 | * @sb: filesystem to do the file handle conversion on |
897 | * @fid: file handle to convert | |
898 | * @fh_len: length of the file handle in bytes | |
899 | * @fh_type: type of file handle | |
900 | * @get_inode: filesystem callback to retrieve inode | |
901 | * | |
902 | * This function decodes @fid as long as it has one of the well-known | |
903 | * Linux filehandle types and calls @get_inode on it to retrieve the | |
904 | * inode for the _parent_ object specified in the file handle if it | |
905 | * is specified in the file handle, or NULL otherwise. | |
906 | */ | |
907 | struct dentry *generic_fh_to_parent(struct super_block *sb, struct fid *fid, | |
908 | int fh_len, int fh_type, struct inode *(*get_inode) | |
909 | (struct super_block *sb, u64 ino, u32 gen)) | |
910 | { | |
911 | struct inode *inode = NULL; | |
912 | ||
913 | if (fh_len <= 2) | |
914 | return NULL; | |
915 | ||
916 | switch (fh_type) { | |
917 | case FILEID_INO32_GEN_PARENT: | |
918 | inode = get_inode(sb, fid->i32.parent_ino, | |
919 | (fh_len > 3 ? fid->i32.parent_gen : 0)); | |
920 | break; | |
921 | } | |
922 | ||
4ea3ada2 | 923 | return d_obtain_alias(inode); |
2596110a CH |
924 | } |
925 | EXPORT_SYMBOL_GPL(generic_fh_to_parent); | |
926 | ||
1b061d92 | 927 | /** |
ac13a829 FF |
928 | * __generic_file_fsync - generic fsync implementation for simple filesystems |
929 | * | |
1b061d92 | 930 | * @file: file to synchronize |
ac13a829 FF |
931 | * @start: start offset in bytes |
932 | * @end: end offset in bytes (inclusive) | |
1b061d92 CH |
933 | * @datasync: only synchronize essential metadata if true |
934 | * | |
935 | * This is a generic implementation of the fsync method for simple | |
936 | * filesystems which track all non-inode metadata in the buffers list | |
937 | * hanging off the address_space structure. | |
938 | */ | |
ac13a829 FF |
939 | int __generic_file_fsync(struct file *file, loff_t start, loff_t end, |
940 | int datasync) | |
d5aacad5 | 941 | { |
7ea80859 | 942 | struct inode *inode = file->f_mapping->host; |
d5aacad5 AV |
943 | int err; |
944 | int ret; | |
945 | ||
02c24a82 JB |
946 | err = filemap_write_and_wait_range(inode->i_mapping, start, end); |
947 | if (err) | |
948 | return err; | |
949 | ||
5955102c | 950 | inode_lock(inode); |
d5aacad5 | 951 | ret = sync_mapping_buffers(inode->i_mapping); |
0ae45f63 | 952 | if (!(inode->i_state & I_DIRTY_ALL)) |
02c24a82 | 953 | goto out; |
d5aacad5 | 954 | if (datasync && !(inode->i_state & I_DIRTY_DATASYNC)) |
02c24a82 | 955 | goto out; |
d5aacad5 | 956 | |
c3765016 | 957 | err = sync_inode_metadata(inode, 1); |
d5aacad5 AV |
958 | if (ret == 0) |
959 | ret = err; | |
ac13a829 | 960 | |
02c24a82 | 961 | out: |
5955102c | 962 | inode_unlock(inode); |
d5aacad5 AV |
963 | return ret; |
964 | } | |
ac13a829 FF |
965 | EXPORT_SYMBOL(__generic_file_fsync); |
966 | ||
967 | /** | |
968 | * generic_file_fsync - generic fsync implementation for simple filesystems | |
969 | * with flush | |
970 | * @file: file to synchronize | |
971 | * @start: start offset in bytes | |
972 | * @end: end offset in bytes (inclusive) | |
973 | * @datasync: only synchronize essential metadata if true | |
974 | * | |
975 | */ | |
976 | ||
977 | int generic_file_fsync(struct file *file, loff_t start, loff_t end, | |
978 | int datasync) | |
979 | { | |
980 | struct inode *inode = file->f_mapping->host; | |
981 | int err; | |
982 | ||
983 | err = __generic_file_fsync(file, start, end, datasync); | |
984 | if (err) | |
985 | return err; | |
986 | return blkdev_issue_flush(inode->i_sb->s_bdev, GFP_KERNEL, NULL); | |
987 | } | |
1b061d92 CH |
988 | EXPORT_SYMBOL(generic_file_fsync); |
989 | ||
30ca22c7 PL |
990 | /** |
991 | * generic_check_addressable - Check addressability of file system | |
992 | * @blocksize_bits: log of file system block size | |
993 | * @num_blocks: number of blocks in file system | |
994 | * | |
995 | * Determine whether a file system with @num_blocks blocks (and a | |
996 | * block size of 2**@blocksize_bits) is addressable by the sector_t | |
997 | * and page cache of the system. Return 0 if so and -EFBIG otherwise. | |
998 | */ | |
999 | int generic_check_addressable(unsigned blocksize_bits, u64 num_blocks) | |
1000 | { | |
1001 | u64 last_fs_block = num_blocks - 1; | |
a33f13ef | 1002 | u64 last_fs_page = |
09cbfeaf | 1003 | last_fs_block >> (PAGE_SHIFT - blocksize_bits); |
30ca22c7 PL |
1004 | |
1005 | if (unlikely(num_blocks == 0)) | |
1006 | return 0; | |
1007 | ||
09cbfeaf | 1008 | if ((blocksize_bits < 9) || (blocksize_bits > PAGE_SHIFT)) |
30ca22c7 PL |
1009 | return -EINVAL; |
1010 | ||
a33f13ef JB |
1011 | if ((last_fs_block > (sector_t)(~0ULL) >> (blocksize_bits - 9)) || |
1012 | (last_fs_page > (pgoff_t)(~0ULL))) { | |
30ca22c7 PL |
1013 | return -EFBIG; |
1014 | } | |
1015 | return 0; | |
1016 | } | |
1017 | EXPORT_SYMBOL(generic_check_addressable); | |
1018 | ||
1b061d92 CH |
1019 | /* |
1020 | * No-op implementation of ->fsync for in-memory filesystems. | |
1021 | */ | |
02c24a82 | 1022 | int noop_fsync(struct file *file, loff_t start, loff_t end, int datasync) |
1b061d92 CH |
1023 | { |
1024 | return 0; | |
1025 | } | |
1b061d92 | 1026 | EXPORT_SYMBOL(noop_fsync); |
87dc800b | 1027 | |
fceef393 AV |
1028 | /* Because kfree isn't assignment-compatible with void(void*) ;-/ */ |
1029 | void kfree_link(void *p) | |
87dc800b | 1030 | { |
fceef393 | 1031 | kfree(p); |
87dc800b | 1032 | } |
fceef393 | 1033 | EXPORT_SYMBOL(kfree_link); |
6987843f AV |
1034 | |
1035 | /* | |
1036 | * nop .set_page_dirty method so that people can use .page_mkwrite on | |
1037 | * anon inodes. | |
1038 | */ | |
1039 | static int anon_set_page_dirty(struct page *page) | |
1040 | { | |
1041 | return 0; | |
1042 | }; | |
1043 | ||
1044 | /* | |
1045 | * A single inode exists for all anon_inode files. Contrary to pipes, | |
1046 | * anon_inode inodes have no associated per-instance data, so we need | |
1047 | * only allocate one of them. | |
1048 | */ | |
1049 | struct inode *alloc_anon_inode(struct super_block *s) | |
1050 | { | |
1051 | static const struct address_space_operations anon_aops = { | |
1052 | .set_page_dirty = anon_set_page_dirty, | |
1053 | }; | |
1054 | struct inode *inode = new_inode_pseudo(s); | |
1055 | ||
1056 | if (!inode) | |
1057 | return ERR_PTR(-ENOMEM); | |
1058 | ||
1059 | inode->i_ino = get_next_ino(); | |
1060 | inode->i_mapping->a_ops = &anon_aops; | |
1061 | ||
1062 | /* | |
1063 | * Mark the inode dirty from the very beginning, | |
1064 | * that way it will never be moved to the dirty | |
1065 | * list because mark_inode_dirty() will think | |
1066 | * that it already _is_ on the dirty list. | |
1067 | */ | |
1068 | inode->i_state = I_DIRTY; | |
1069 | inode->i_mode = S_IRUSR | S_IWUSR; | |
1070 | inode->i_uid = current_fsuid(); | |
1071 | inode->i_gid = current_fsgid(); | |
1072 | inode->i_flags |= S_PRIVATE; | |
1073 | inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; | |
1074 | return inode; | |
1075 | } | |
1076 | EXPORT_SYMBOL(alloc_anon_inode); | |
1c994a09 JL |
1077 | |
1078 | /** | |
1079 | * simple_nosetlease - generic helper for prohibiting leases | |
1080 | * @filp: file pointer | |
1081 | * @arg: type of lease to obtain | |
1082 | * @flp: new lease supplied for insertion | |
e6f5c789 | 1083 | * @priv: private data for lm_setup operation |
1c994a09 JL |
1084 | * |
1085 | * Generic helper for filesystems that do not wish to allow leases to be set. | |
1086 | * All arguments are ignored and it just returns -EINVAL. | |
1087 | */ | |
1088 | int | |
e6f5c789 JL |
1089 | simple_nosetlease(struct file *filp, long arg, struct file_lock **flp, |
1090 | void **priv) | |
1c994a09 JL |
1091 | { |
1092 | return -EINVAL; | |
1093 | } | |
1094 | EXPORT_SYMBOL(simple_nosetlease); | |
61ba64fc | 1095 | |
6b255391 | 1096 | const char *simple_get_link(struct dentry *dentry, struct inode *inode, |
fceef393 | 1097 | struct delayed_call *done) |
61ba64fc | 1098 | { |
6b255391 | 1099 | return inode->i_link; |
61ba64fc | 1100 | } |
6b255391 | 1101 | EXPORT_SYMBOL(simple_get_link); |
61ba64fc AV |
1102 | |
1103 | const struct inode_operations simple_symlink_inode_operations = { | |
6b255391 | 1104 | .get_link = simple_get_link, |
61ba64fc AV |
1105 | .readlink = generic_readlink |
1106 | }; | |
1107 | EXPORT_SYMBOL(simple_symlink_inode_operations); | |
fbabfd0f EB |
1108 | |
1109 | /* | |
1110 | * Operations for a permanently empty directory. | |
1111 | */ | |
1112 | static struct dentry *empty_dir_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags) | |
1113 | { | |
1114 | return ERR_PTR(-ENOENT); | |
1115 | } | |
1116 | ||
1117 | static int empty_dir_getattr(struct vfsmount *mnt, struct dentry *dentry, | |
1118 | struct kstat *stat) | |
1119 | { | |
1120 | struct inode *inode = d_inode(dentry); | |
1121 | generic_fillattr(inode, stat); | |
1122 | return 0; | |
1123 | } | |
1124 | ||
1125 | static int empty_dir_setattr(struct dentry *dentry, struct iattr *attr) | |
1126 | { | |
1127 | return -EPERM; | |
1128 | } | |
1129 | ||
3767e255 AV |
1130 | static int empty_dir_setxattr(struct dentry *dentry, struct inode *inode, |
1131 | const char *name, const void *value, | |
1132 | size_t size, int flags) | |
fbabfd0f EB |
1133 | { |
1134 | return -EOPNOTSUPP; | |
1135 | } | |
1136 | ||
ce23e640 AV |
1137 | static ssize_t empty_dir_getxattr(struct dentry *dentry, struct inode *inode, |
1138 | const char *name, void *value, size_t size) | |
fbabfd0f EB |
1139 | { |
1140 | return -EOPNOTSUPP; | |
1141 | } | |
1142 | ||
1143 | static int empty_dir_removexattr(struct dentry *dentry, const char *name) | |
1144 | { | |
1145 | return -EOPNOTSUPP; | |
1146 | } | |
1147 | ||
1148 | static ssize_t empty_dir_listxattr(struct dentry *dentry, char *list, size_t size) | |
1149 | { | |
1150 | return -EOPNOTSUPP; | |
1151 | } | |
1152 | ||
1153 | static const struct inode_operations empty_dir_inode_operations = { | |
1154 | .lookup = empty_dir_lookup, | |
1155 | .permission = generic_permission, | |
1156 | .setattr = empty_dir_setattr, | |
1157 | .getattr = empty_dir_getattr, | |
1158 | .setxattr = empty_dir_setxattr, | |
1159 | .getxattr = empty_dir_getxattr, | |
1160 | .removexattr = empty_dir_removexattr, | |
1161 | .listxattr = empty_dir_listxattr, | |
1162 | }; | |
1163 | ||
1164 | static loff_t empty_dir_llseek(struct file *file, loff_t offset, int whence) | |
1165 | { | |
1166 | /* An empty directory has two entries . and .. at offsets 0 and 1 */ | |
1167 | return generic_file_llseek_size(file, offset, whence, 2, 2); | |
1168 | } | |
1169 | ||
1170 | static int empty_dir_readdir(struct file *file, struct dir_context *ctx) | |
1171 | { | |
1172 | dir_emit_dots(file, ctx); | |
1173 | return 0; | |
1174 | } | |
1175 | ||
1176 | static const struct file_operations empty_dir_operations = { | |
1177 | .llseek = empty_dir_llseek, | |
1178 | .read = generic_read_dir, | |
c51da20c | 1179 | .iterate_shared = empty_dir_readdir, |
fbabfd0f EB |
1180 | .fsync = noop_fsync, |
1181 | }; | |
1182 | ||
1183 | ||
1184 | void make_empty_dir_inode(struct inode *inode) | |
1185 | { | |
1186 | set_nlink(inode, 2); | |
1187 | inode->i_mode = S_IFDIR | S_IRUGO | S_IXUGO; | |
1188 | inode->i_uid = GLOBAL_ROOT_UID; | |
1189 | inode->i_gid = GLOBAL_ROOT_GID; | |
1190 | inode->i_rdev = 0; | |
4b75de86 | 1191 | inode->i_size = 0; |
fbabfd0f EB |
1192 | inode->i_blkbits = PAGE_SHIFT; |
1193 | inode->i_blocks = 0; | |
1194 | ||
1195 | inode->i_op = &empty_dir_inode_operations; | |
1196 | inode->i_fop = &empty_dir_operations; | |
1197 | } | |
1198 | ||
1199 | bool is_empty_dir_inode(struct inode *inode) | |
1200 | { | |
1201 | return (inode->i_fop == &empty_dir_operations) && | |
1202 | (inode->i_op == &empty_dir_inode_operations); | |
1203 | } |