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