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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 | |
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 | { | |
ebaaa80e AV |
92 | unsigned *seq = &parent->d_inode->i_dir_seq, n; |
93 | struct dentry *res; | |
4f42c1b5 | 94 | struct list_head *p; |
ebaaa80e AV |
95 | bool skipped; |
96 | int i; | |
97 | ||
98 | retry: | |
99 | i = count; | |
100 | skipped = false; | |
101 | n = smp_load_acquire(seq) & ~1; | |
102 | res = NULL; | |
103 | rcu_read_lock(); | |
4f42c1b5 AV |
104 | for (p = from->next; p != &parent->d_subdirs; p = p->next) { |
105 | struct dentry *d = list_entry(p, struct dentry, d_child); | |
ebaaa80e AV |
106 | if (!simple_positive(d)) { |
107 | skipped = true; | |
108 | } else if (!--i) { | |
4f42c1b5 AV |
109 | res = d; |
110 | break; | |
111 | } | |
112 | } | |
ebaaa80e AV |
113 | rcu_read_unlock(); |
114 | if (skipped) { | |
115 | smp_rmb(); | |
116 | if (unlikely(*seq != n)) | |
117 | goto retry; | |
118 | } | |
4f42c1b5 AV |
119 | return res; |
120 | } | |
121 | ||
122 | static void move_cursor(struct dentry *cursor, struct list_head *after) | |
123 | { | |
124 | struct dentry *parent = cursor->d_parent; | |
ebaaa80e | 125 | unsigned n, *seq = &parent->d_inode->i_dir_seq; |
4f42c1b5 | 126 | spin_lock(&parent->d_lock); |
ebaaa80e AV |
127 | for (;;) { |
128 | n = *seq; | |
129 | if (!(n & 1) && cmpxchg(seq, n, n + 1) == n) | |
130 | break; | |
131 | cpu_relax(); | |
132 | } | |
4f42c1b5 AV |
133 | __list_del(cursor->d_child.prev, cursor->d_child.next); |
134 | if (after) | |
135 | list_add(&cursor->d_child, after); | |
136 | else | |
137 | list_add_tail(&cursor->d_child, &parent->d_subdirs); | |
ebaaa80e | 138 | smp_store_release(seq, n + 2); |
4f42c1b5 AV |
139 | spin_unlock(&parent->d_lock); |
140 | } | |
141 | ||
965c8e59 | 142 | loff_t dcache_dir_lseek(struct file *file, loff_t offset, int whence) |
1da177e4 | 143 | { |
2fd6b7f5 | 144 | struct dentry *dentry = file->f_path.dentry; |
965c8e59 | 145 | switch (whence) { |
1da177e4 LT |
146 | case 1: |
147 | offset += file->f_pos; | |
148 | case 0: | |
149 | if (offset >= 0) | |
150 | break; | |
151 | default: | |
1da177e4 LT |
152 | return -EINVAL; |
153 | } | |
154 | if (offset != file->f_pos) { | |
155 | file->f_pos = offset; | |
156 | if (file->f_pos >= 2) { | |
1da177e4 | 157 | struct dentry *cursor = file->private_data; |
4f42c1b5 | 158 | struct dentry *to; |
1da177e4 LT |
159 | loff_t n = file->f_pos - 2; |
160 | ||
274f5b04 | 161 | inode_lock_shared(dentry->d_inode); |
4f42c1b5 AV |
162 | to = next_positive(dentry, &dentry->d_subdirs, n); |
163 | move_cursor(cursor, to ? &to->d_child : NULL); | |
274f5b04 | 164 | inode_unlock_shared(dentry->d_inode); |
1da177e4 LT |
165 | } |
166 | } | |
1da177e4 LT |
167 | return offset; |
168 | } | |
12f38872 | 169 | EXPORT_SYMBOL(dcache_dir_lseek); |
1da177e4 LT |
170 | |
171 | /* Relationship between i_mode and the DT_xxx types */ | |
172 | static inline unsigned char dt_type(struct inode *inode) | |
173 | { | |
174 | return (inode->i_mode >> 12) & 15; | |
175 | } | |
176 | ||
177 | /* | |
178 | * Directory is locked and all positive dentries in it are safe, since | |
179 | * for ramfs-type trees they can't go away without unlink() or rmdir(), | |
180 | * both impossible due to the lock on directory. | |
181 | */ | |
182 | ||
5f99f4e7 | 183 | int dcache_readdir(struct file *file, struct dir_context *ctx) |
1da177e4 | 184 | { |
5f99f4e7 AV |
185 | struct dentry *dentry = file->f_path.dentry; |
186 | struct dentry *cursor = file->private_data; | |
4f42c1b5 AV |
187 | struct list_head *p = &cursor->d_child; |
188 | struct dentry *next; | |
189 | bool moved = false; | |
1da177e4 | 190 | |
5f99f4e7 AV |
191 | if (!dir_emit_dots(file, ctx)) |
192 | return 0; | |
5f99f4e7 | 193 | |
4f42c1b5 AV |
194 | if (ctx->pos == 2) |
195 | p = &dentry->d_subdirs; | |
196 | while ((next = next_positive(dentry, p, 1)) != NULL) { | |
5f99f4e7 | 197 | if (!dir_emit(ctx, next->d_name.name, next->d_name.len, |
dea655c2 | 198 | d_inode(next)->i_ino, dt_type(d_inode(next)))) |
4f42c1b5 AV |
199 | break; |
200 | moved = true; | |
201 | p = &next->d_child; | |
5f99f4e7 | 202 | ctx->pos++; |
1da177e4 | 203 | } |
4f42c1b5 AV |
204 | if (moved) |
205 | move_cursor(cursor, p); | |
1da177e4 LT |
206 | return 0; |
207 | } | |
12f38872 | 208 | EXPORT_SYMBOL(dcache_readdir); |
1da177e4 LT |
209 | |
210 | ssize_t generic_read_dir(struct file *filp, char __user *buf, size_t siz, loff_t *ppos) | |
211 | { | |
212 | return -EISDIR; | |
213 | } | |
12f38872 | 214 | EXPORT_SYMBOL(generic_read_dir); |
1da177e4 | 215 | |
4b6f5d20 | 216 | const struct file_operations simple_dir_operations = { |
1da177e4 LT |
217 | .open = dcache_dir_open, |
218 | .release = dcache_dir_close, | |
219 | .llseek = dcache_dir_lseek, | |
220 | .read = generic_read_dir, | |
4e82901c | 221 | .iterate_shared = dcache_readdir, |
1b061d92 | 222 | .fsync = noop_fsync, |
1da177e4 | 223 | }; |
12f38872 | 224 | EXPORT_SYMBOL(simple_dir_operations); |
1da177e4 | 225 | |
92e1d5be | 226 | const struct inode_operations simple_dir_inode_operations = { |
1da177e4 LT |
227 | .lookup = simple_lookup, |
228 | }; | |
12f38872 | 229 | EXPORT_SYMBOL(simple_dir_inode_operations); |
1da177e4 | 230 | |
759b9775 HD |
231 | static const struct super_operations simple_super_operations = { |
232 | .statfs = simple_statfs, | |
233 | }; | |
234 | ||
1da177e4 LT |
235 | /* |
236 | * Common helper for pseudo-filesystems (sockfs, pipefs, bdev - stuff that | |
237 | * will never be mountable) | |
238 | */ | |
51139ada | 239 | struct dentry *mount_pseudo(struct file_system_type *fs_type, char *name, |
c74a1cbb AV |
240 | const struct super_operations *ops, |
241 | const struct dentry_operations *dops, unsigned long magic) | |
1da177e4 | 242 | { |
9249e17f | 243 | struct super_block *s; |
1da177e4 LT |
244 | struct dentry *dentry; |
245 | struct inode *root; | |
26fe5750 | 246 | struct qstr d_name = QSTR_INIT(name, strlen(name)); |
1da177e4 | 247 | |
9249e17f | 248 | s = sget(fs_type, NULL, set_anon_super, MS_NOUSER, NULL); |
1da177e4 | 249 | if (IS_ERR(s)) |
51139ada | 250 | return ERR_CAST(s); |
1da177e4 | 251 | |
89a4eb4b | 252 | s->s_maxbytes = MAX_LFS_FILESIZE; |
3971e1a9 AN |
253 | s->s_blocksize = PAGE_SIZE; |
254 | s->s_blocksize_bits = PAGE_SHIFT; | |
1da177e4 | 255 | s->s_magic = magic; |
759b9775 | 256 | s->s_op = ops ? ops : &simple_super_operations; |
1da177e4 LT |
257 | s->s_time_gran = 1; |
258 | root = new_inode(s); | |
259 | if (!root) | |
260 | goto Enomem; | |
1a1c9bb4 JL |
261 | /* |
262 | * since this is the first inode, make it number 1. New inodes created | |
263 | * after this must take care not to collide with it (by passing | |
264 | * max_reserved of 1 to iunique). | |
265 | */ | |
266 | root->i_ino = 1; | |
1da177e4 | 267 | root->i_mode = S_IFDIR | S_IRUSR | S_IWUSR; |
1da177e4 | 268 | root->i_atime = root->i_mtime = root->i_ctime = CURRENT_TIME; |
a4464dbc | 269 | dentry = __d_alloc(s, &d_name); |
1da177e4 LT |
270 | if (!dentry) { |
271 | iput(root); | |
272 | goto Enomem; | |
273 | } | |
1da177e4 LT |
274 | d_instantiate(dentry, root); |
275 | s->s_root = dentry; | |
c74a1cbb | 276 | s->s_d_op = dops; |
1da177e4 | 277 | s->s_flags |= MS_ACTIVE; |
51139ada | 278 | return dget(s->s_root); |
1da177e4 LT |
279 | |
280 | Enomem: | |
6f5bbff9 | 281 | deactivate_locked_super(s); |
51139ada | 282 | return ERR_PTR(-ENOMEM); |
1da177e4 | 283 | } |
12f38872 | 284 | EXPORT_SYMBOL(mount_pseudo); |
1da177e4 | 285 | |
20955e89 SB |
286 | int simple_open(struct inode *inode, struct file *file) |
287 | { | |
288 | if (inode->i_private) | |
289 | file->private_data = inode->i_private; | |
290 | return 0; | |
291 | } | |
12f38872 | 292 | EXPORT_SYMBOL(simple_open); |
20955e89 | 293 | |
1da177e4 LT |
294 | int simple_link(struct dentry *old_dentry, struct inode *dir, struct dentry *dentry) |
295 | { | |
dea655c2 | 296 | struct inode *inode = d_inode(old_dentry); |
1da177e4 LT |
297 | |
298 | inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME; | |
d8c76e6f | 299 | inc_nlink(inode); |
7de9c6ee | 300 | ihold(inode); |
1da177e4 LT |
301 | dget(dentry); |
302 | d_instantiate(dentry, inode); | |
303 | return 0; | |
304 | } | |
12f38872 | 305 | EXPORT_SYMBOL(simple_link); |
1da177e4 | 306 | |
1da177e4 LT |
307 | int simple_empty(struct dentry *dentry) |
308 | { | |
309 | struct dentry *child; | |
310 | int ret = 0; | |
311 | ||
2fd6b7f5 | 312 | spin_lock(&dentry->d_lock); |
946e51f2 | 313 | list_for_each_entry(child, &dentry->d_subdirs, d_child) { |
da502956 NP |
314 | spin_lock_nested(&child->d_lock, DENTRY_D_LOCK_NESTED); |
315 | if (simple_positive(child)) { | |
316 | spin_unlock(&child->d_lock); | |
1da177e4 | 317 | goto out; |
da502956 NP |
318 | } |
319 | spin_unlock(&child->d_lock); | |
320 | } | |
1da177e4 LT |
321 | ret = 1; |
322 | out: | |
2fd6b7f5 | 323 | spin_unlock(&dentry->d_lock); |
1da177e4 LT |
324 | return ret; |
325 | } | |
12f38872 | 326 | EXPORT_SYMBOL(simple_empty); |
1da177e4 LT |
327 | |
328 | int simple_unlink(struct inode *dir, struct dentry *dentry) | |
329 | { | |
dea655c2 | 330 | struct inode *inode = d_inode(dentry); |
1da177e4 LT |
331 | |
332 | inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME; | |
9a53c3a7 | 333 | drop_nlink(inode); |
1da177e4 LT |
334 | dput(dentry); |
335 | return 0; | |
336 | } | |
12f38872 | 337 | EXPORT_SYMBOL(simple_unlink); |
1da177e4 LT |
338 | |
339 | int simple_rmdir(struct inode *dir, struct dentry *dentry) | |
340 | { | |
341 | if (!simple_empty(dentry)) | |
342 | return -ENOTEMPTY; | |
343 | ||
dea655c2 | 344 | drop_nlink(d_inode(dentry)); |
1da177e4 | 345 | simple_unlink(dir, dentry); |
9a53c3a7 | 346 | drop_nlink(dir); |
1da177e4 LT |
347 | return 0; |
348 | } | |
12f38872 | 349 | EXPORT_SYMBOL(simple_rmdir); |
1da177e4 LT |
350 | |
351 | int simple_rename(struct inode *old_dir, struct dentry *old_dentry, | |
352 | struct inode *new_dir, struct dentry *new_dentry) | |
353 | { | |
dea655c2 | 354 | struct inode *inode = d_inode(old_dentry); |
e36cb0b8 | 355 | int they_are_dirs = d_is_dir(old_dentry); |
1da177e4 LT |
356 | |
357 | if (!simple_empty(new_dentry)) | |
358 | return -ENOTEMPTY; | |
359 | ||
dea655c2 | 360 | if (d_really_is_positive(new_dentry)) { |
1da177e4 | 361 | simple_unlink(new_dir, new_dentry); |
841590ce | 362 | if (they_are_dirs) { |
dea655c2 | 363 | drop_nlink(d_inode(new_dentry)); |
9a53c3a7 | 364 | drop_nlink(old_dir); |
841590ce | 365 | } |
1da177e4 | 366 | } else if (they_are_dirs) { |
9a53c3a7 | 367 | drop_nlink(old_dir); |
d8c76e6f | 368 | inc_nlink(new_dir); |
1da177e4 LT |
369 | } |
370 | ||
371 | old_dir->i_ctime = old_dir->i_mtime = new_dir->i_ctime = | |
372 | new_dir->i_mtime = inode->i_ctime = CURRENT_TIME; | |
373 | ||
374 | return 0; | |
375 | } | |
12f38872 | 376 | EXPORT_SYMBOL(simple_rename); |
1da177e4 | 377 | |
7bb46a67 | 378 | /** |
eef2380c | 379 | * simple_setattr - setattr for simple filesystem |
7bb46a67 NP |
380 | * @dentry: dentry |
381 | * @iattr: iattr structure | |
382 | * | |
383 | * Returns 0 on success, -error on failure. | |
384 | * | |
eef2380c CH |
385 | * simple_setattr is a simple ->setattr implementation without a proper |
386 | * implementation of size changes. | |
387 | * | |
388 | * It can either be used for in-memory filesystems or special files | |
389 | * on simple regular filesystems. Anything that needs to change on-disk | |
390 | * or wire state on size changes needs its own setattr method. | |
7bb46a67 NP |
391 | */ |
392 | int simple_setattr(struct dentry *dentry, struct iattr *iattr) | |
393 | { | |
dea655c2 | 394 | struct inode *inode = d_inode(dentry); |
7bb46a67 NP |
395 | int error; |
396 | ||
397 | error = inode_change_ok(inode, iattr); | |
398 | if (error) | |
399 | return error; | |
400 | ||
2c27c65e CH |
401 | if (iattr->ia_valid & ATTR_SIZE) |
402 | truncate_setsize(inode, iattr->ia_size); | |
6a1a90ad | 403 | setattr_copy(inode, iattr); |
eef2380c CH |
404 | mark_inode_dirty(inode); |
405 | return 0; | |
7bb46a67 NP |
406 | } |
407 | EXPORT_SYMBOL(simple_setattr); | |
408 | ||
1da177e4 LT |
409 | int simple_readpage(struct file *file, struct page *page) |
410 | { | |
c0d92cbc | 411 | clear_highpage(page); |
1da177e4 LT |
412 | flush_dcache_page(page); |
413 | SetPageUptodate(page); | |
1da177e4 LT |
414 | unlock_page(page); |
415 | return 0; | |
416 | } | |
12f38872 | 417 | EXPORT_SYMBOL(simple_readpage); |
1da177e4 | 418 | |
afddba49 NP |
419 | int simple_write_begin(struct file *file, struct address_space *mapping, |
420 | loff_t pos, unsigned len, unsigned flags, | |
421 | struct page **pagep, void **fsdata) | |
422 | { | |
423 | struct page *page; | |
424 | pgoff_t index; | |
afddba49 | 425 | |
09cbfeaf | 426 | index = pos >> PAGE_SHIFT; |
afddba49 | 427 | |
54566b2c | 428 | page = grab_cache_page_write_begin(mapping, index, flags); |
afddba49 NP |
429 | if (!page) |
430 | return -ENOMEM; | |
431 | ||
432 | *pagep = page; | |
433 | ||
09cbfeaf KS |
434 | if (!PageUptodate(page) && (len != PAGE_SIZE)) { |
435 | unsigned from = pos & (PAGE_SIZE - 1); | |
193cf4b9 | 436 | |
09cbfeaf | 437 | zero_user_segments(page, 0, from, from + len, PAGE_SIZE); |
193cf4b9 BH |
438 | } |
439 | return 0; | |
afddba49 | 440 | } |
12f38872 | 441 | EXPORT_SYMBOL(simple_write_begin); |
afddba49 | 442 | |
ad2a722f BH |
443 | /** |
444 | * simple_write_end - .write_end helper for non-block-device FSes | |
445 | * @available: See .write_end of address_space_operations | |
446 | * @file: " | |
447 | * @mapping: " | |
448 | * @pos: " | |
449 | * @len: " | |
450 | * @copied: " | |
451 | * @page: " | |
452 | * @fsdata: " | |
453 | * | |
454 | * simple_write_end does the minimum needed for updating a page after writing is | |
455 | * done. It has the same API signature as the .write_end of | |
456 | * address_space_operations vector. So it can just be set onto .write_end for | |
457 | * FSes that don't need any other processing. i_mutex is assumed to be held. | |
458 | * Block based filesystems should use generic_write_end(). | |
459 | * NOTE: Even though i_size might get updated by this function, mark_inode_dirty | |
460 | * is not called, so a filesystem that actually does store data in .write_inode | |
461 | * should extend on what's done here with a call to mark_inode_dirty() in the | |
462 | * case that i_size has changed. | |
463 | */ | |
afddba49 NP |
464 | int simple_write_end(struct file *file, struct address_space *mapping, |
465 | loff_t pos, unsigned len, unsigned copied, | |
466 | struct page *page, void *fsdata) | |
467 | { | |
ad2a722f BH |
468 | struct inode *inode = page->mapping->host; |
469 | loff_t last_pos = pos + copied; | |
afddba49 NP |
470 | |
471 | /* zero the stale part of the page if we did a short copy */ | |
472 | if (copied < len) { | |
09cbfeaf | 473 | unsigned from = pos & (PAGE_SIZE - 1); |
ad2a722f BH |
474 | |
475 | zero_user(page, from + copied, len - copied); | |
afddba49 NP |
476 | } |
477 | ||
ad2a722f BH |
478 | if (!PageUptodate(page)) |
479 | SetPageUptodate(page); | |
480 | /* | |
481 | * No need to use i_size_read() here, the i_size | |
482 | * cannot change under us because we hold the i_mutex. | |
483 | */ | |
484 | if (last_pos > inode->i_size) | |
485 | i_size_write(inode, last_pos); | |
afddba49 | 486 | |
ad2a722f | 487 | set_page_dirty(page); |
afddba49 | 488 | unlock_page(page); |
09cbfeaf | 489 | put_page(page); |
afddba49 NP |
490 | |
491 | return copied; | |
492 | } | |
12f38872 | 493 | EXPORT_SYMBOL(simple_write_end); |
afddba49 | 494 | |
1a1c9bb4 JL |
495 | /* |
496 | * the inodes created here are not hashed. If you use iunique to generate | |
497 | * unique inode values later for this filesystem, then you must take care | |
498 | * to pass it an appropriate max_reserved value to avoid collisions. | |
499 | */ | |
7d683a09 RS |
500 | int simple_fill_super(struct super_block *s, unsigned long magic, |
501 | struct tree_descr *files) | |
1da177e4 | 502 | { |
1da177e4 LT |
503 | struct inode *inode; |
504 | struct dentry *root; | |
505 | struct dentry *dentry; | |
506 | int i; | |
507 | ||
09cbfeaf KS |
508 | s->s_blocksize = PAGE_SIZE; |
509 | s->s_blocksize_bits = PAGE_SHIFT; | |
1da177e4 | 510 | s->s_magic = magic; |
759b9775 | 511 | s->s_op = &simple_super_operations; |
1da177e4 LT |
512 | s->s_time_gran = 1; |
513 | ||
514 | inode = new_inode(s); | |
515 | if (!inode) | |
516 | return -ENOMEM; | |
1a1c9bb4 JL |
517 | /* |
518 | * because the root inode is 1, the files array must not contain an | |
519 | * entry at index 1 | |
520 | */ | |
521 | inode->i_ino = 1; | |
1da177e4 | 522 | inode->i_mode = S_IFDIR | 0755; |
1da177e4 LT |
523 | inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; |
524 | inode->i_op = &simple_dir_inode_operations; | |
525 | inode->i_fop = &simple_dir_operations; | |
bfe86848 | 526 | set_nlink(inode, 2); |
48fde701 AV |
527 | root = d_make_root(inode); |
528 | if (!root) | |
1da177e4 | 529 | return -ENOMEM; |
1da177e4 LT |
530 | for (i = 0; !files->name || files->name[0]; i++, files++) { |
531 | if (!files->name) | |
532 | continue; | |
1a1c9bb4 JL |
533 | |
534 | /* warn if it tries to conflict with the root inode */ | |
535 | if (unlikely(i == 1)) | |
536 | printk(KERN_WARNING "%s: %s passed in a files array" | |
537 | "with an index of 1!\n", __func__, | |
538 | s->s_type->name); | |
539 | ||
1da177e4 LT |
540 | dentry = d_alloc_name(root, files->name); |
541 | if (!dentry) | |
542 | goto out; | |
543 | inode = new_inode(s); | |
32096ea1 KK |
544 | if (!inode) { |
545 | dput(dentry); | |
1da177e4 | 546 | goto out; |
32096ea1 | 547 | } |
1da177e4 | 548 | inode->i_mode = S_IFREG | files->mode; |
1da177e4 LT |
549 | inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; |
550 | inode->i_fop = files->ops; | |
551 | inode->i_ino = i; | |
552 | d_add(dentry, inode); | |
553 | } | |
554 | s->s_root = root; | |
555 | return 0; | |
556 | out: | |
557 | d_genocide(root); | |
640946f2 | 558 | shrink_dcache_parent(root); |
1da177e4 LT |
559 | dput(root); |
560 | return -ENOMEM; | |
561 | } | |
12f38872 | 562 | EXPORT_SYMBOL(simple_fill_super); |
1da177e4 LT |
563 | |
564 | static DEFINE_SPINLOCK(pin_fs_lock); | |
565 | ||
1f5ce9e9 | 566 | int simple_pin_fs(struct file_system_type *type, struct vfsmount **mount, int *count) |
1da177e4 LT |
567 | { |
568 | struct vfsmount *mnt = NULL; | |
569 | spin_lock(&pin_fs_lock); | |
570 | if (unlikely(!*mount)) { | |
571 | spin_unlock(&pin_fs_lock); | |
2452992a | 572 | mnt = vfs_kern_mount(type, MS_KERNMOUNT, type->name, NULL); |
1da177e4 LT |
573 | if (IS_ERR(mnt)) |
574 | return PTR_ERR(mnt); | |
575 | spin_lock(&pin_fs_lock); | |
576 | if (!*mount) | |
577 | *mount = mnt; | |
578 | } | |
579 | mntget(*mount); | |
580 | ++*count; | |
581 | spin_unlock(&pin_fs_lock); | |
582 | mntput(mnt); | |
583 | return 0; | |
584 | } | |
12f38872 | 585 | EXPORT_SYMBOL(simple_pin_fs); |
1da177e4 LT |
586 | |
587 | void simple_release_fs(struct vfsmount **mount, int *count) | |
588 | { | |
589 | struct vfsmount *mnt; | |
590 | spin_lock(&pin_fs_lock); | |
591 | mnt = *mount; | |
592 | if (!--*count) | |
593 | *mount = NULL; | |
594 | spin_unlock(&pin_fs_lock); | |
595 | mntput(mnt); | |
596 | } | |
12f38872 | 597 | EXPORT_SYMBOL(simple_release_fs); |
1da177e4 | 598 | |
6d1029b5 AM |
599 | /** |
600 | * simple_read_from_buffer - copy data from the buffer to user space | |
601 | * @to: the user space buffer to read to | |
602 | * @count: the maximum number of bytes to read | |
603 | * @ppos: the current position in the buffer | |
604 | * @from: the buffer to read from | |
605 | * @available: the size of the buffer | |
606 | * | |
607 | * The simple_read_from_buffer() function reads up to @count bytes from the | |
608 | * buffer @from at offset @ppos into the user space address starting at @to. | |
609 | * | |
610 | * On success, the number of bytes read is returned and the offset @ppos is | |
611 | * advanced by this number, or negative value is returned on error. | |
612 | **/ | |
1da177e4 LT |
613 | ssize_t simple_read_from_buffer(void __user *to, size_t count, loff_t *ppos, |
614 | const void *from, size_t available) | |
615 | { | |
616 | loff_t pos = *ppos; | |
14be2746 SR |
617 | size_t ret; |
618 | ||
1da177e4 LT |
619 | if (pos < 0) |
620 | return -EINVAL; | |
14be2746 | 621 | if (pos >= available || !count) |
1da177e4 LT |
622 | return 0; |
623 | if (count > available - pos) | |
624 | count = available - pos; | |
14be2746 SR |
625 | ret = copy_to_user(to, from + pos, count); |
626 | if (ret == count) | |
1da177e4 | 627 | return -EFAULT; |
14be2746 | 628 | count -= ret; |
1da177e4 LT |
629 | *ppos = pos + count; |
630 | return count; | |
631 | } | |
12f38872 | 632 | EXPORT_SYMBOL(simple_read_from_buffer); |
1da177e4 | 633 | |
6a727b43 JS |
634 | /** |
635 | * simple_write_to_buffer - copy data from user space to the buffer | |
636 | * @to: the buffer to write to | |
637 | * @available: the size of the buffer | |
638 | * @ppos: the current position in the buffer | |
639 | * @from: the user space buffer to read from | |
640 | * @count: the maximum number of bytes to read | |
641 | * | |
642 | * The simple_write_to_buffer() function reads up to @count bytes from the user | |
643 | * space address starting at @from into the buffer @to at offset @ppos. | |
644 | * | |
645 | * On success, the number of bytes written is returned and the offset @ppos is | |
646 | * advanced by this number, or negative value is returned on error. | |
647 | **/ | |
648 | ssize_t simple_write_to_buffer(void *to, size_t available, loff_t *ppos, | |
649 | const void __user *from, size_t count) | |
650 | { | |
651 | loff_t pos = *ppos; | |
652 | size_t res; | |
653 | ||
654 | if (pos < 0) | |
655 | return -EINVAL; | |
656 | if (pos >= available || !count) | |
657 | return 0; | |
658 | if (count > available - pos) | |
659 | count = available - pos; | |
660 | res = copy_from_user(to + pos, from, count); | |
661 | if (res == count) | |
662 | return -EFAULT; | |
663 | count -= res; | |
664 | *ppos = pos + count; | |
665 | return count; | |
666 | } | |
12f38872 | 667 | EXPORT_SYMBOL(simple_write_to_buffer); |
6a727b43 | 668 | |
6d1029b5 AM |
669 | /** |
670 | * memory_read_from_buffer - copy data from the buffer | |
671 | * @to: the kernel space buffer to read to | |
672 | * @count: the maximum number of bytes to read | |
673 | * @ppos: the current position in the buffer | |
674 | * @from: the buffer to read from | |
675 | * @available: the size of the buffer | |
676 | * | |
677 | * The memory_read_from_buffer() function reads up to @count bytes from the | |
678 | * buffer @from at offset @ppos into the kernel space address starting at @to. | |
679 | * | |
680 | * On success, the number of bytes read is returned and the offset @ppos is | |
681 | * advanced by this number, or negative value is returned on error. | |
682 | **/ | |
93b07113 AM |
683 | ssize_t memory_read_from_buffer(void *to, size_t count, loff_t *ppos, |
684 | const void *from, size_t available) | |
685 | { | |
686 | loff_t pos = *ppos; | |
687 | ||
688 | if (pos < 0) | |
689 | return -EINVAL; | |
690 | if (pos >= available) | |
691 | return 0; | |
692 | if (count > available - pos) | |
693 | count = available - pos; | |
694 | memcpy(to, from + pos, count); | |
695 | *ppos = pos + count; | |
696 | ||
697 | return count; | |
698 | } | |
12f38872 | 699 | EXPORT_SYMBOL(memory_read_from_buffer); |
93b07113 | 700 | |
1da177e4 LT |
701 | /* |
702 | * Transaction based IO. | |
703 | * The file expects a single write which triggers the transaction, and then | |
704 | * possibly a read which collects the result - which is stored in a | |
705 | * file-local buffer. | |
706 | */ | |
76791ab2 IM |
707 | |
708 | void simple_transaction_set(struct file *file, size_t n) | |
709 | { | |
710 | struct simple_transaction_argresp *ar = file->private_data; | |
711 | ||
712 | BUG_ON(n > SIMPLE_TRANSACTION_LIMIT); | |
713 | ||
714 | /* | |
715 | * The barrier ensures that ar->size will really remain zero until | |
716 | * ar->data is ready for reading. | |
717 | */ | |
718 | smp_mb(); | |
719 | ar->size = n; | |
720 | } | |
12f38872 | 721 | EXPORT_SYMBOL(simple_transaction_set); |
76791ab2 | 722 | |
1da177e4 LT |
723 | char *simple_transaction_get(struct file *file, const char __user *buf, size_t size) |
724 | { | |
725 | struct simple_transaction_argresp *ar; | |
726 | static DEFINE_SPINLOCK(simple_transaction_lock); | |
727 | ||
728 | if (size > SIMPLE_TRANSACTION_LIMIT - 1) | |
729 | return ERR_PTR(-EFBIG); | |
730 | ||
731 | ar = (struct simple_transaction_argresp *)get_zeroed_page(GFP_KERNEL); | |
732 | if (!ar) | |
733 | return ERR_PTR(-ENOMEM); | |
734 | ||
735 | spin_lock(&simple_transaction_lock); | |
736 | ||
737 | /* only one write allowed per open */ | |
738 | if (file->private_data) { | |
739 | spin_unlock(&simple_transaction_lock); | |
740 | free_page((unsigned long)ar); | |
741 | return ERR_PTR(-EBUSY); | |
742 | } | |
743 | ||
744 | file->private_data = ar; | |
745 | ||
746 | spin_unlock(&simple_transaction_lock); | |
747 | ||
748 | if (copy_from_user(ar->data, buf, size)) | |
749 | return ERR_PTR(-EFAULT); | |
750 | ||
751 | return ar->data; | |
752 | } | |
12f38872 | 753 | EXPORT_SYMBOL(simple_transaction_get); |
1da177e4 LT |
754 | |
755 | ssize_t simple_transaction_read(struct file *file, char __user *buf, size_t size, loff_t *pos) | |
756 | { | |
757 | struct simple_transaction_argresp *ar = file->private_data; | |
758 | ||
759 | if (!ar) | |
760 | return 0; | |
761 | return simple_read_from_buffer(buf, size, pos, ar->data, ar->size); | |
762 | } | |
12f38872 | 763 | EXPORT_SYMBOL(simple_transaction_read); |
1da177e4 LT |
764 | |
765 | int simple_transaction_release(struct inode *inode, struct file *file) | |
766 | { | |
767 | free_page((unsigned long)file->private_data); | |
768 | return 0; | |
769 | } | |
12f38872 | 770 | EXPORT_SYMBOL(simple_transaction_release); |
1da177e4 | 771 | |
acaefc25 AB |
772 | /* Simple attribute files */ |
773 | ||
774 | struct simple_attr { | |
8b88b099 CH |
775 | int (*get)(void *, u64 *); |
776 | int (*set)(void *, u64); | |
acaefc25 AB |
777 | char get_buf[24]; /* enough to store a u64 and "\n\0" */ |
778 | char set_buf[24]; | |
779 | void *data; | |
780 | const char *fmt; /* format for read operation */ | |
7cf34c76 | 781 | struct mutex mutex; /* protects access to these buffers */ |
acaefc25 AB |
782 | }; |
783 | ||
784 | /* simple_attr_open is called by an actual attribute open file operation | |
785 | * to set the attribute specific access operations. */ | |
786 | int simple_attr_open(struct inode *inode, struct file *file, | |
8b88b099 | 787 | int (*get)(void *, u64 *), int (*set)(void *, u64), |
acaefc25 AB |
788 | const char *fmt) |
789 | { | |
790 | struct simple_attr *attr; | |
791 | ||
792 | attr = kmalloc(sizeof(*attr), GFP_KERNEL); | |
793 | if (!attr) | |
794 | return -ENOMEM; | |
795 | ||
796 | attr->get = get; | |
797 | attr->set = set; | |
8e18e294 | 798 | attr->data = inode->i_private; |
acaefc25 | 799 | attr->fmt = fmt; |
7cf34c76 | 800 | mutex_init(&attr->mutex); |
acaefc25 AB |
801 | |
802 | file->private_data = attr; | |
803 | ||
804 | return nonseekable_open(inode, file); | |
805 | } | |
12f38872 | 806 | EXPORT_SYMBOL_GPL(simple_attr_open); |
acaefc25 | 807 | |
74bedc4d | 808 | int simple_attr_release(struct inode *inode, struct file *file) |
acaefc25 AB |
809 | { |
810 | kfree(file->private_data); | |
811 | return 0; | |
812 | } | |
12f38872 | 813 | EXPORT_SYMBOL_GPL(simple_attr_release); /* GPL-only? This? Really? */ |
acaefc25 AB |
814 | |
815 | /* read from the buffer that is filled with the get function */ | |
816 | ssize_t simple_attr_read(struct file *file, char __user *buf, | |
817 | size_t len, loff_t *ppos) | |
818 | { | |
819 | struct simple_attr *attr; | |
820 | size_t size; | |
821 | ssize_t ret; | |
822 | ||
823 | attr = file->private_data; | |
824 | ||
825 | if (!attr->get) | |
826 | return -EACCES; | |
827 | ||
9261303a CH |
828 | ret = mutex_lock_interruptible(&attr->mutex); |
829 | if (ret) | |
830 | return ret; | |
831 | ||
8b88b099 | 832 | if (*ppos) { /* continued read */ |
acaefc25 | 833 | size = strlen(attr->get_buf); |
8b88b099 CH |
834 | } else { /* first read */ |
835 | u64 val; | |
836 | ret = attr->get(attr->data, &val); | |
837 | if (ret) | |
838 | goto out; | |
839 | ||
acaefc25 | 840 | size = scnprintf(attr->get_buf, sizeof(attr->get_buf), |
8b88b099 CH |
841 | attr->fmt, (unsigned long long)val); |
842 | } | |
acaefc25 AB |
843 | |
844 | ret = simple_read_from_buffer(buf, len, ppos, attr->get_buf, size); | |
8b88b099 | 845 | out: |
7cf34c76 | 846 | mutex_unlock(&attr->mutex); |
acaefc25 AB |
847 | return ret; |
848 | } | |
12f38872 | 849 | EXPORT_SYMBOL_GPL(simple_attr_read); |
acaefc25 AB |
850 | |
851 | /* interpret the buffer as a number to call the set function with */ | |
852 | ssize_t simple_attr_write(struct file *file, const char __user *buf, | |
853 | size_t len, loff_t *ppos) | |
854 | { | |
855 | struct simple_attr *attr; | |
856 | u64 val; | |
857 | size_t size; | |
858 | ssize_t ret; | |
859 | ||
860 | attr = file->private_data; | |
acaefc25 AB |
861 | if (!attr->set) |
862 | return -EACCES; | |
863 | ||
9261303a CH |
864 | ret = mutex_lock_interruptible(&attr->mutex); |
865 | if (ret) | |
866 | return ret; | |
867 | ||
acaefc25 AB |
868 | ret = -EFAULT; |
869 | size = min(sizeof(attr->set_buf) - 1, len); | |
870 | if (copy_from_user(attr->set_buf, buf, size)) | |
871 | goto out; | |
872 | ||
acaefc25 | 873 | attr->set_buf[size] = '\0'; |
f7b88631 | 874 | val = simple_strtoll(attr->set_buf, NULL, 0); |
05cc0cee WF |
875 | ret = attr->set(attr->data, val); |
876 | if (ret == 0) | |
877 | ret = len; /* on success, claim we got the whole input */ | |
acaefc25 | 878 | out: |
7cf34c76 | 879 | mutex_unlock(&attr->mutex); |
acaefc25 AB |
880 | return ret; |
881 | } | |
12f38872 | 882 | EXPORT_SYMBOL_GPL(simple_attr_write); |
acaefc25 | 883 | |
2596110a CH |
884 | /** |
885 | * generic_fh_to_dentry - generic helper for the fh_to_dentry export operation | |
886 | * @sb: filesystem to do the file handle conversion on | |
887 | * @fid: file handle to convert | |
888 | * @fh_len: length of the file handle in bytes | |
889 | * @fh_type: type of file handle | |
890 | * @get_inode: filesystem callback to retrieve inode | |
891 | * | |
892 | * This function decodes @fid as long as it has one of the well-known | |
893 | * Linux filehandle types and calls @get_inode on it to retrieve the | |
894 | * inode for the object specified in the file handle. | |
895 | */ | |
896 | struct dentry *generic_fh_to_dentry(struct super_block *sb, struct fid *fid, | |
897 | int fh_len, int fh_type, struct inode *(*get_inode) | |
898 | (struct super_block *sb, u64 ino, u32 gen)) | |
899 | { | |
900 | struct inode *inode = NULL; | |
901 | ||
902 | if (fh_len < 2) | |
903 | return NULL; | |
904 | ||
905 | switch (fh_type) { | |
906 | case FILEID_INO32_GEN: | |
907 | case FILEID_INO32_GEN_PARENT: | |
908 | inode = get_inode(sb, fid->i32.ino, fid->i32.gen); | |
909 | break; | |
910 | } | |
911 | ||
4ea3ada2 | 912 | return d_obtain_alias(inode); |
2596110a CH |
913 | } |
914 | EXPORT_SYMBOL_GPL(generic_fh_to_dentry); | |
915 | ||
916 | /** | |
ca186830 | 917 | * generic_fh_to_parent - generic helper for the fh_to_parent export operation |
2596110a CH |
918 | * @sb: filesystem to do the file handle conversion on |
919 | * @fid: file handle to convert | |
920 | * @fh_len: length of the file handle in bytes | |
921 | * @fh_type: type of file handle | |
922 | * @get_inode: filesystem callback to retrieve inode | |
923 | * | |
924 | * This function decodes @fid as long as it has one of the well-known | |
925 | * Linux filehandle types and calls @get_inode on it to retrieve the | |
926 | * inode for the _parent_ object specified in the file handle if it | |
927 | * is specified in the file handle, or NULL otherwise. | |
928 | */ | |
929 | struct dentry *generic_fh_to_parent(struct super_block *sb, struct fid *fid, | |
930 | int fh_len, int fh_type, struct inode *(*get_inode) | |
931 | (struct super_block *sb, u64 ino, u32 gen)) | |
932 | { | |
933 | struct inode *inode = NULL; | |
934 | ||
935 | if (fh_len <= 2) | |
936 | return NULL; | |
937 | ||
938 | switch (fh_type) { | |
939 | case FILEID_INO32_GEN_PARENT: | |
940 | inode = get_inode(sb, fid->i32.parent_ino, | |
941 | (fh_len > 3 ? fid->i32.parent_gen : 0)); | |
942 | break; | |
943 | } | |
944 | ||
4ea3ada2 | 945 | return d_obtain_alias(inode); |
2596110a CH |
946 | } |
947 | EXPORT_SYMBOL_GPL(generic_fh_to_parent); | |
948 | ||
1b061d92 | 949 | /** |
ac13a829 FF |
950 | * __generic_file_fsync - generic fsync implementation for simple filesystems |
951 | * | |
1b061d92 | 952 | * @file: file to synchronize |
ac13a829 FF |
953 | * @start: start offset in bytes |
954 | * @end: end offset in bytes (inclusive) | |
1b061d92 CH |
955 | * @datasync: only synchronize essential metadata if true |
956 | * | |
957 | * This is a generic implementation of the fsync method for simple | |
958 | * filesystems which track all non-inode metadata in the buffers list | |
959 | * hanging off the address_space structure. | |
960 | */ | |
ac13a829 FF |
961 | int __generic_file_fsync(struct file *file, loff_t start, loff_t end, |
962 | int datasync) | |
d5aacad5 | 963 | { |
7ea80859 | 964 | struct inode *inode = file->f_mapping->host; |
d5aacad5 AV |
965 | int err; |
966 | int ret; | |
967 | ||
02c24a82 JB |
968 | err = filemap_write_and_wait_range(inode->i_mapping, start, end); |
969 | if (err) | |
970 | return err; | |
971 | ||
5955102c | 972 | inode_lock(inode); |
d5aacad5 | 973 | ret = sync_mapping_buffers(inode->i_mapping); |
0ae45f63 | 974 | if (!(inode->i_state & I_DIRTY_ALL)) |
02c24a82 | 975 | goto out; |
d5aacad5 | 976 | if (datasync && !(inode->i_state & I_DIRTY_DATASYNC)) |
02c24a82 | 977 | goto out; |
d5aacad5 | 978 | |
c3765016 | 979 | err = sync_inode_metadata(inode, 1); |
d5aacad5 AV |
980 | if (ret == 0) |
981 | ret = err; | |
ac13a829 | 982 | |
02c24a82 | 983 | out: |
5955102c | 984 | inode_unlock(inode); |
d5aacad5 AV |
985 | return ret; |
986 | } | |
ac13a829 FF |
987 | EXPORT_SYMBOL(__generic_file_fsync); |
988 | ||
989 | /** | |
990 | * generic_file_fsync - generic fsync implementation for simple filesystems | |
991 | * with flush | |
992 | * @file: file to synchronize | |
993 | * @start: start offset in bytes | |
994 | * @end: end offset in bytes (inclusive) | |
995 | * @datasync: only synchronize essential metadata if true | |
996 | * | |
997 | */ | |
998 | ||
999 | int generic_file_fsync(struct file *file, loff_t start, loff_t end, | |
1000 | int datasync) | |
1001 | { | |
1002 | struct inode *inode = file->f_mapping->host; | |
1003 | int err; | |
1004 | ||
1005 | err = __generic_file_fsync(file, start, end, datasync); | |
1006 | if (err) | |
1007 | return err; | |
1008 | return blkdev_issue_flush(inode->i_sb->s_bdev, GFP_KERNEL, NULL); | |
1009 | } | |
1b061d92 CH |
1010 | EXPORT_SYMBOL(generic_file_fsync); |
1011 | ||
30ca22c7 PL |
1012 | /** |
1013 | * generic_check_addressable - Check addressability of file system | |
1014 | * @blocksize_bits: log of file system block size | |
1015 | * @num_blocks: number of blocks in file system | |
1016 | * | |
1017 | * Determine whether a file system with @num_blocks blocks (and a | |
1018 | * block size of 2**@blocksize_bits) is addressable by the sector_t | |
1019 | * and page cache of the system. Return 0 if so and -EFBIG otherwise. | |
1020 | */ | |
1021 | int generic_check_addressable(unsigned blocksize_bits, u64 num_blocks) | |
1022 | { | |
1023 | u64 last_fs_block = num_blocks - 1; | |
a33f13ef | 1024 | u64 last_fs_page = |
09cbfeaf | 1025 | last_fs_block >> (PAGE_SHIFT - blocksize_bits); |
30ca22c7 PL |
1026 | |
1027 | if (unlikely(num_blocks == 0)) | |
1028 | return 0; | |
1029 | ||
09cbfeaf | 1030 | if ((blocksize_bits < 9) || (blocksize_bits > PAGE_SHIFT)) |
30ca22c7 PL |
1031 | return -EINVAL; |
1032 | ||
a33f13ef JB |
1033 | if ((last_fs_block > (sector_t)(~0ULL) >> (blocksize_bits - 9)) || |
1034 | (last_fs_page > (pgoff_t)(~0ULL))) { | |
30ca22c7 PL |
1035 | return -EFBIG; |
1036 | } | |
1037 | return 0; | |
1038 | } | |
1039 | EXPORT_SYMBOL(generic_check_addressable); | |
1040 | ||
1b061d92 CH |
1041 | /* |
1042 | * No-op implementation of ->fsync for in-memory filesystems. | |
1043 | */ | |
02c24a82 | 1044 | int noop_fsync(struct file *file, loff_t start, loff_t end, int datasync) |
1b061d92 CH |
1045 | { |
1046 | return 0; | |
1047 | } | |
1b061d92 | 1048 | EXPORT_SYMBOL(noop_fsync); |
87dc800b | 1049 | |
fceef393 AV |
1050 | /* Because kfree isn't assignment-compatible with void(void*) ;-/ */ |
1051 | void kfree_link(void *p) | |
87dc800b | 1052 | { |
fceef393 | 1053 | kfree(p); |
87dc800b | 1054 | } |
fceef393 | 1055 | EXPORT_SYMBOL(kfree_link); |
6987843f AV |
1056 | |
1057 | /* | |
1058 | * nop .set_page_dirty method so that people can use .page_mkwrite on | |
1059 | * anon inodes. | |
1060 | */ | |
1061 | static int anon_set_page_dirty(struct page *page) | |
1062 | { | |
1063 | return 0; | |
1064 | }; | |
1065 | ||
1066 | /* | |
1067 | * A single inode exists for all anon_inode files. Contrary to pipes, | |
1068 | * anon_inode inodes have no associated per-instance data, so we need | |
1069 | * only allocate one of them. | |
1070 | */ | |
1071 | struct inode *alloc_anon_inode(struct super_block *s) | |
1072 | { | |
1073 | static const struct address_space_operations anon_aops = { | |
1074 | .set_page_dirty = anon_set_page_dirty, | |
1075 | }; | |
1076 | struct inode *inode = new_inode_pseudo(s); | |
1077 | ||
1078 | if (!inode) | |
1079 | return ERR_PTR(-ENOMEM); | |
1080 | ||
1081 | inode->i_ino = get_next_ino(); | |
1082 | inode->i_mapping->a_ops = &anon_aops; | |
1083 | ||
1084 | /* | |
1085 | * Mark the inode dirty from the very beginning, | |
1086 | * that way it will never be moved to the dirty | |
1087 | * list because mark_inode_dirty() will think | |
1088 | * that it already _is_ on the dirty list. | |
1089 | */ | |
1090 | inode->i_state = I_DIRTY; | |
1091 | inode->i_mode = S_IRUSR | S_IWUSR; | |
1092 | inode->i_uid = current_fsuid(); | |
1093 | inode->i_gid = current_fsgid(); | |
1094 | inode->i_flags |= S_PRIVATE; | |
1095 | inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; | |
1096 | return inode; | |
1097 | } | |
1098 | EXPORT_SYMBOL(alloc_anon_inode); | |
1c994a09 JL |
1099 | |
1100 | /** | |
1101 | * simple_nosetlease - generic helper for prohibiting leases | |
1102 | * @filp: file pointer | |
1103 | * @arg: type of lease to obtain | |
1104 | * @flp: new lease supplied for insertion | |
e6f5c789 | 1105 | * @priv: private data for lm_setup operation |
1c994a09 JL |
1106 | * |
1107 | * Generic helper for filesystems that do not wish to allow leases to be set. | |
1108 | * All arguments are ignored and it just returns -EINVAL. | |
1109 | */ | |
1110 | int | |
e6f5c789 JL |
1111 | simple_nosetlease(struct file *filp, long arg, struct file_lock **flp, |
1112 | void **priv) | |
1c994a09 JL |
1113 | { |
1114 | return -EINVAL; | |
1115 | } | |
1116 | EXPORT_SYMBOL(simple_nosetlease); | |
61ba64fc | 1117 | |
6b255391 | 1118 | const char *simple_get_link(struct dentry *dentry, struct inode *inode, |
fceef393 | 1119 | struct delayed_call *done) |
61ba64fc | 1120 | { |
6b255391 | 1121 | return inode->i_link; |
61ba64fc | 1122 | } |
6b255391 | 1123 | EXPORT_SYMBOL(simple_get_link); |
61ba64fc AV |
1124 | |
1125 | const struct inode_operations simple_symlink_inode_operations = { | |
6b255391 | 1126 | .get_link = simple_get_link, |
61ba64fc AV |
1127 | .readlink = generic_readlink |
1128 | }; | |
1129 | EXPORT_SYMBOL(simple_symlink_inode_operations); | |
fbabfd0f EB |
1130 | |
1131 | /* | |
1132 | * Operations for a permanently empty directory. | |
1133 | */ | |
1134 | static struct dentry *empty_dir_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags) | |
1135 | { | |
1136 | return ERR_PTR(-ENOENT); | |
1137 | } | |
1138 | ||
1139 | static int empty_dir_getattr(struct vfsmount *mnt, struct dentry *dentry, | |
1140 | struct kstat *stat) | |
1141 | { | |
1142 | struct inode *inode = d_inode(dentry); | |
1143 | generic_fillattr(inode, stat); | |
1144 | return 0; | |
1145 | } | |
1146 | ||
1147 | static int empty_dir_setattr(struct dentry *dentry, struct iattr *attr) | |
1148 | { | |
1149 | return -EPERM; | |
1150 | } | |
1151 | ||
3767e255 AV |
1152 | static int empty_dir_setxattr(struct dentry *dentry, struct inode *inode, |
1153 | const char *name, const void *value, | |
1154 | size_t size, int flags) | |
fbabfd0f EB |
1155 | { |
1156 | return -EOPNOTSUPP; | |
1157 | } | |
1158 | ||
ce23e640 AV |
1159 | static ssize_t empty_dir_getxattr(struct dentry *dentry, struct inode *inode, |
1160 | const char *name, void *value, size_t size) | |
fbabfd0f EB |
1161 | { |
1162 | return -EOPNOTSUPP; | |
1163 | } | |
1164 | ||
1165 | static int empty_dir_removexattr(struct dentry *dentry, const char *name) | |
1166 | { | |
1167 | return -EOPNOTSUPP; | |
1168 | } | |
1169 | ||
1170 | static ssize_t empty_dir_listxattr(struct dentry *dentry, char *list, size_t size) | |
1171 | { | |
1172 | return -EOPNOTSUPP; | |
1173 | } | |
1174 | ||
1175 | static const struct inode_operations empty_dir_inode_operations = { | |
1176 | .lookup = empty_dir_lookup, | |
1177 | .permission = generic_permission, | |
1178 | .setattr = empty_dir_setattr, | |
1179 | .getattr = empty_dir_getattr, | |
1180 | .setxattr = empty_dir_setxattr, | |
1181 | .getxattr = empty_dir_getxattr, | |
1182 | .removexattr = empty_dir_removexattr, | |
1183 | .listxattr = empty_dir_listxattr, | |
1184 | }; | |
1185 | ||
1186 | static loff_t empty_dir_llseek(struct file *file, loff_t offset, int whence) | |
1187 | { | |
1188 | /* An empty directory has two entries . and .. at offsets 0 and 1 */ | |
1189 | return generic_file_llseek_size(file, offset, whence, 2, 2); | |
1190 | } | |
1191 | ||
1192 | static int empty_dir_readdir(struct file *file, struct dir_context *ctx) | |
1193 | { | |
1194 | dir_emit_dots(file, ctx); | |
1195 | return 0; | |
1196 | } | |
1197 | ||
1198 | static const struct file_operations empty_dir_operations = { | |
1199 | .llseek = empty_dir_llseek, | |
1200 | .read = generic_read_dir, | |
c51da20c | 1201 | .iterate_shared = empty_dir_readdir, |
fbabfd0f EB |
1202 | .fsync = noop_fsync, |
1203 | }; | |
1204 | ||
1205 | ||
1206 | void make_empty_dir_inode(struct inode *inode) | |
1207 | { | |
1208 | set_nlink(inode, 2); | |
1209 | inode->i_mode = S_IFDIR | S_IRUGO | S_IXUGO; | |
1210 | inode->i_uid = GLOBAL_ROOT_UID; | |
1211 | inode->i_gid = GLOBAL_ROOT_GID; | |
1212 | inode->i_rdev = 0; | |
4b75de86 | 1213 | inode->i_size = 0; |
fbabfd0f EB |
1214 | inode->i_blkbits = PAGE_SHIFT; |
1215 | inode->i_blocks = 0; | |
1216 | ||
1217 | inode->i_op = &empty_dir_inode_operations; | |
1218 | inode->i_fop = &empty_dir_operations; | |
1219 | } | |
1220 | ||
1221 | bool is_empty_dir_inode(struct inode *inode) | |
1222 | { | |
1223 | return (inode->i_fop == &empty_dir_operations) && | |
1224 | (inode->i_op == &empty_dir_inode_operations); | |
1225 | } |