]>
Commit | Line | Data |
---|---|---|
457c8996 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
1da177e4 LT |
2 | /* |
3 | * fs/libfs.c | |
4 | * Library for filesystems writers. | |
5 | */ | |
6 | ||
ac13a829 | 7 | #include <linux/blkdev.h> |
630d9c47 | 8 | #include <linux/export.h> |
1da177e4 | 9 | #include <linux/pagemap.h> |
5a0e3ad6 | 10 | #include <linux/slab.h> |
5b825c3a | 11 | #include <linux/cred.h> |
1da177e4 LT |
12 | #include <linux/mount.h> |
13 | #include <linux/vfs.h> | |
7bb46a67 | 14 | #include <linux/quotaops.h> |
7cf34c76 | 15 | #include <linux/mutex.h> |
87dc800b | 16 | #include <linux/namei.h> |
2596110a | 17 | #include <linux/exportfs.h> |
d5aacad5 | 18 | #include <linux/writeback.h> |
ff01bb48 | 19 | #include <linux/buffer_head.h> /* sync_mapping_buffers */ |
31d6d5ce DH |
20 | #include <linux/fs_context.h> |
21 | #include <linux/pseudo_fs.h> | |
a3d1e7eb | 22 | #include <linux/fsnotify.h> |
7cf34c76 | 23 | |
7c0f6ba6 | 24 | #include <linux/uaccess.h> |
1da177e4 | 25 | |
a4464dbc AV |
26 | #include "internal.h" |
27 | ||
a528d35e DH |
28 | int simple_getattr(const struct path *path, struct kstat *stat, |
29 | u32 request_mask, unsigned int query_flags) | |
1da177e4 | 30 | { |
a528d35e | 31 | struct inode *inode = d_inode(path->dentry); |
1da177e4 | 32 | generic_fillattr(inode, stat); |
09cbfeaf | 33 | stat->blocks = inode->i_mapping->nrpages << (PAGE_SHIFT - 9); |
1da177e4 LT |
34 | return 0; |
35 | } | |
12f38872 | 36 | EXPORT_SYMBOL(simple_getattr); |
1da177e4 | 37 | |
726c3342 | 38 | int simple_statfs(struct dentry *dentry, struct kstatfs *buf) |
1da177e4 | 39 | { |
726c3342 | 40 | buf->f_type = dentry->d_sb->s_magic; |
09cbfeaf | 41 | buf->f_bsize = PAGE_SIZE; |
1da177e4 LT |
42 | buf->f_namelen = NAME_MAX; |
43 | return 0; | |
44 | } | |
12f38872 | 45 | EXPORT_SYMBOL(simple_statfs); |
1da177e4 LT |
46 | |
47 | /* | |
48 | * Retaining negative dentries for an in-memory filesystem just wastes | |
49 | * memory and lookup time: arrange for them to be deleted immediately. | |
50 | */ | |
b26d4cd3 | 51 | int always_delete_dentry(const struct dentry *dentry) |
1da177e4 LT |
52 | { |
53 | return 1; | |
54 | } | |
b26d4cd3 AV |
55 | EXPORT_SYMBOL(always_delete_dentry); |
56 | ||
57 | const struct dentry_operations simple_dentry_operations = { | |
58 | .d_delete = always_delete_dentry, | |
59 | }; | |
60 | EXPORT_SYMBOL(simple_dentry_operations); | |
1da177e4 LT |
61 | |
62 | /* | |
63 | * Lookup the data. This is trivial - if the dentry didn't already | |
64 | * exist, we know it is negative. Set d_op to delete negative dentries. | |
65 | */ | |
00cd8dd3 | 66 | struct dentry *simple_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags) |
1da177e4 | 67 | { |
1da177e4 LT |
68 | if (dentry->d_name.len > NAME_MAX) |
69 | return ERR_PTR(-ENAMETOOLONG); | |
74931da7 AV |
70 | if (!dentry->d_sb->s_d_op) |
71 | d_set_d_op(dentry, &simple_dentry_operations); | |
1da177e4 LT |
72 | d_add(dentry, NULL); |
73 | return NULL; | |
74 | } | |
12f38872 | 75 | EXPORT_SYMBOL(simple_lookup); |
1da177e4 | 76 | |
1da177e4 LT |
77 | int dcache_dir_open(struct inode *inode, struct file *file) |
78 | { | |
ba65dc5e | 79 | file->private_data = d_alloc_cursor(file->f_path.dentry); |
1da177e4 LT |
80 | |
81 | return file->private_data ? 0 : -ENOMEM; | |
82 | } | |
12f38872 | 83 | EXPORT_SYMBOL(dcache_dir_open); |
1da177e4 LT |
84 | |
85 | int dcache_dir_close(struct inode *inode, struct file *file) | |
86 | { | |
87 | dput(file->private_data); | |
88 | return 0; | |
89 | } | |
12f38872 | 90 | EXPORT_SYMBOL(dcache_dir_close); |
1da177e4 | 91 | |
4f42c1b5 | 92 | /* parent is locked at least shared */ |
d4f4de5e AV |
93 | /* |
94 | * Returns an element of siblings' list. | |
95 | * We are looking for <count>th positive after <p>; if | |
26b6c984 AV |
96 | * found, dentry is grabbed and returned to caller. |
97 | * If no such element exists, NULL is returned. | |
d4f4de5e | 98 | */ |
26b6c984 | 99 | static struct dentry *scan_positives(struct dentry *cursor, |
d4f4de5e AV |
100 | struct list_head *p, |
101 | loff_t count, | |
26b6c984 | 102 | struct dentry *last) |
4f42c1b5 | 103 | { |
d4f4de5e AV |
104 | struct dentry *dentry = cursor->d_parent, *found = NULL; |
105 | ||
106 | spin_lock(&dentry->d_lock); | |
107 | while ((p = p->next) != &dentry->d_subdirs) { | |
4f42c1b5 | 108 | struct dentry *d = list_entry(p, struct dentry, d_child); |
d4f4de5e AV |
109 | // we must at least skip cursors, to avoid livelocks |
110 | if (d->d_flags & DCACHE_DENTRY_CURSOR) | |
111 | continue; | |
112 | if (simple_positive(d) && !--count) { | |
113 | spin_lock_nested(&d->d_lock, DENTRY_D_LOCK_NESTED); | |
114 | if (simple_positive(d)) | |
115 | found = dget_dlock(d); | |
116 | spin_unlock(&d->d_lock); | |
117 | if (likely(found)) | |
118 | break; | |
119 | count = 1; | |
120 | } | |
121 | if (need_resched()) { | |
122 | list_move(&cursor->d_child, p); | |
123 | p = &cursor->d_child; | |
124 | spin_unlock(&dentry->d_lock); | |
125 | cond_resched(); | |
126 | spin_lock(&dentry->d_lock); | |
4f42c1b5 AV |
127 | } |
128 | } | |
d4f4de5e | 129 | spin_unlock(&dentry->d_lock); |
26b6c984 AV |
130 | dput(last); |
131 | return found; | |
4f42c1b5 AV |
132 | } |
133 | ||
965c8e59 | 134 | loff_t dcache_dir_lseek(struct file *file, loff_t offset, int whence) |
1da177e4 | 135 | { |
2fd6b7f5 | 136 | struct dentry *dentry = file->f_path.dentry; |
965c8e59 | 137 | switch (whence) { |
1da177e4 LT |
138 | case 1: |
139 | offset += file->f_pos; | |
0a4c9265 | 140 | /* fall through */ |
1da177e4 LT |
141 | case 0: |
142 | if (offset >= 0) | |
143 | break; | |
0a4c9265 | 144 | /* fall through */ |
1da177e4 | 145 | default: |
1da177e4 LT |
146 | return -EINVAL; |
147 | } | |
148 | if (offset != file->f_pos) { | |
d4f4de5e AV |
149 | struct dentry *cursor = file->private_data; |
150 | struct dentry *to = NULL; | |
d4f4de5e | 151 | |
d4f4de5e AV |
152 | inode_lock_shared(dentry->d_inode); |
153 | ||
26b6c984 AV |
154 | if (offset > 2) |
155 | to = scan_positives(cursor, &dentry->d_subdirs, | |
156 | offset - 2, NULL); | |
157 | spin_lock(&dentry->d_lock); | |
158 | if (to) | |
159 | list_move(&cursor->d_child, &to->d_child); | |
160 | else | |
d4f4de5e | 161 | list_del_init(&cursor->d_child); |
26b6c984 | 162 | spin_unlock(&dentry->d_lock); |
d4f4de5e AV |
163 | dput(to); |
164 | ||
26b6c984 AV |
165 | file->f_pos = offset; |
166 | ||
d4f4de5e | 167 | inode_unlock_shared(dentry->d_inode); |
1da177e4 | 168 | } |
1da177e4 LT |
169 | return offset; |
170 | } | |
12f38872 | 171 | EXPORT_SYMBOL(dcache_dir_lseek); |
1da177e4 LT |
172 | |
173 | /* Relationship between i_mode and the DT_xxx types */ | |
174 | static inline unsigned char dt_type(struct inode *inode) | |
175 | { | |
176 | return (inode->i_mode >> 12) & 15; | |
177 | } | |
178 | ||
179 | /* | |
180 | * Directory is locked and all positive dentries in it are safe, since | |
181 | * for ramfs-type trees they can't go away without unlink() or rmdir(), | |
182 | * both impossible due to the lock on directory. | |
183 | */ | |
184 | ||
5f99f4e7 | 185 | int dcache_readdir(struct file *file, struct dir_context *ctx) |
1da177e4 | 186 | { |
5f99f4e7 AV |
187 | struct dentry *dentry = file->f_path.dentry; |
188 | struct dentry *cursor = file->private_data; | |
d4f4de5e AV |
189 | struct list_head *anchor = &dentry->d_subdirs; |
190 | struct dentry *next = NULL; | |
191 | struct list_head *p; | |
1da177e4 | 192 | |
5f99f4e7 AV |
193 | if (!dir_emit_dots(file, ctx)) |
194 | return 0; | |
5f99f4e7 | 195 | |
4f42c1b5 | 196 | if (ctx->pos == 2) |
d4f4de5e | 197 | p = anchor; |
26b6c984 | 198 | else if (!list_empty(&cursor->d_child)) |
d4f4de5e | 199 | p = &cursor->d_child; |
26b6c984 AV |
200 | else |
201 | return 0; | |
d4f4de5e | 202 | |
26b6c984 | 203 | while ((next = scan_positives(cursor, p, 1, next)) != NULL) { |
5f99f4e7 | 204 | if (!dir_emit(ctx, next->d_name.name, next->d_name.len, |
dea655c2 | 205 | d_inode(next)->i_ino, dt_type(d_inode(next)))) |
4f42c1b5 | 206 | break; |
5f99f4e7 | 207 | ctx->pos++; |
26b6c984 | 208 | p = &next->d_child; |
1da177e4 | 209 | } |
d4f4de5e | 210 | spin_lock(&dentry->d_lock); |
26b6c984 AV |
211 | if (next) |
212 | list_move_tail(&cursor->d_child, &next->d_child); | |
213 | else | |
214 | list_del_init(&cursor->d_child); | |
d4f4de5e AV |
215 | spin_unlock(&dentry->d_lock); |
216 | dput(next); | |
217 | ||
1da177e4 LT |
218 | return 0; |
219 | } | |
12f38872 | 220 | EXPORT_SYMBOL(dcache_readdir); |
1da177e4 LT |
221 | |
222 | ssize_t generic_read_dir(struct file *filp, char __user *buf, size_t siz, loff_t *ppos) | |
223 | { | |
224 | return -EISDIR; | |
225 | } | |
12f38872 | 226 | EXPORT_SYMBOL(generic_read_dir); |
1da177e4 | 227 | |
4b6f5d20 | 228 | const struct file_operations simple_dir_operations = { |
1da177e4 LT |
229 | .open = dcache_dir_open, |
230 | .release = dcache_dir_close, | |
231 | .llseek = dcache_dir_lseek, | |
232 | .read = generic_read_dir, | |
4e82901c | 233 | .iterate_shared = dcache_readdir, |
1b061d92 | 234 | .fsync = noop_fsync, |
1da177e4 | 235 | }; |
12f38872 | 236 | EXPORT_SYMBOL(simple_dir_operations); |
1da177e4 | 237 | |
92e1d5be | 238 | const struct inode_operations simple_dir_inode_operations = { |
1da177e4 LT |
239 | .lookup = simple_lookup, |
240 | }; | |
12f38872 | 241 | EXPORT_SYMBOL(simple_dir_inode_operations); |
1da177e4 | 242 | |
a3d1e7eb AV |
243 | static struct dentry *find_next_child(struct dentry *parent, struct dentry *prev) |
244 | { | |
245 | struct dentry *child = NULL; | |
246 | struct list_head *p = prev ? &prev->d_child : &parent->d_subdirs; | |
247 | ||
248 | spin_lock(&parent->d_lock); | |
249 | while ((p = p->next) != &parent->d_subdirs) { | |
250 | struct dentry *d = container_of(p, struct dentry, d_child); | |
251 | if (simple_positive(d)) { | |
252 | spin_lock_nested(&d->d_lock, DENTRY_D_LOCK_NESTED); | |
253 | if (simple_positive(d)) | |
254 | child = dget_dlock(d); | |
255 | spin_unlock(&d->d_lock); | |
256 | if (likely(child)) | |
257 | break; | |
258 | } | |
259 | } | |
260 | spin_unlock(&parent->d_lock); | |
261 | dput(prev); | |
262 | return child; | |
263 | } | |
264 | ||
265 | void simple_recursive_removal(struct dentry *dentry, | |
266 | void (*callback)(struct dentry *)) | |
267 | { | |
268 | struct dentry *this = dget(dentry); | |
269 | while (true) { | |
270 | struct dentry *victim = NULL, *child; | |
271 | struct inode *inode = this->d_inode; | |
272 | ||
273 | inode_lock(inode); | |
274 | if (d_is_dir(this)) | |
275 | inode->i_flags |= S_DEAD; | |
276 | while ((child = find_next_child(this, victim)) == NULL) { | |
277 | // kill and ascend | |
278 | // update metadata while it's still locked | |
279 | inode->i_ctime = current_time(inode); | |
280 | clear_nlink(inode); | |
281 | inode_unlock(inode); | |
282 | victim = this; | |
283 | this = this->d_parent; | |
284 | inode = this->d_inode; | |
285 | inode_lock(inode); | |
286 | if (simple_positive(victim)) { | |
287 | d_invalidate(victim); // avoid lost mounts | |
288 | if (d_is_dir(victim)) | |
289 | fsnotify_rmdir(inode, victim); | |
290 | else | |
291 | fsnotify_unlink(inode, victim); | |
292 | if (callback) | |
293 | callback(victim); | |
294 | dput(victim); // unpin it | |
295 | } | |
296 | if (victim == dentry) { | |
297 | inode->i_ctime = inode->i_mtime = | |
298 | current_time(inode); | |
299 | if (d_is_dir(dentry)) | |
300 | drop_nlink(inode); | |
301 | inode_unlock(inode); | |
302 | dput(dentry); | |
303 | return; | |
304 | } | |
305 | } | |
306 | inode_unlock(inode); | |
307 | this = child; | |
308 | } | |
309 | } | |
310 | EXPORT_SYMBOL(simple_recursive_removal); | |
311 | ||
759b9775 HD |
312 | static const struct super_operations simple_super_operations = { |
313 | .statfs = simple_statfs, | |
314 | }; | |
315 | ||
db2c246a | 316 | static int pseudo_fs_fill_super(struct super_block *s, struct fs_context *fc) |
1da177e4 | 317 | { |
31d6d5ce | 318 | struct pseudo_fs_context *ctx = fc->fs_private; |
1da177e4 | 319 | struct inode *root; |
1da177e4 | 320 | |
89a4eb4b | 321 | s->s_maxbytes = MAX_LFS_FILESIZE; |
3971e1a9 AN |
322 | s->s_blocksize = PAGE_SIZE; |
323 | s->s_blocksize_bits = PAGE_SHIFT; | |
8d9e46d8 AV |
324 | s->s_magic = ctx->magic; |
325 | s->s_op = ctx->ops ?: &simple_super_operations; | |
326 | s->s_xattr = ctx->xattr; | |
1da177e4 LT |
327 | s->s_time_gran = 1; |
328 | root = new_inode(s); | |
329 | if (!root) | |
db2c246a DH |
330 | return -ENOMEM; |
331 | ||
1a1c9bb4 JL |
332 | /* |
333 | * since this is the first inode, make it number 1. New inodes created | |
334 | * after this must take care not to collide with it (by passing | |
335 | * max_reserved of 1 to iunique). | |
336 | */ | |
337 | root->i_ino = 1; | |
1da177e4 | 338 | root->i_mode = S_IFDIR | S_IRUSR | S_IWUSR; |
078cd827 | 339 | root->i_atime = root->i_mtime = root->i_ctime = current_time(root); |
8d9e46d8 AV |
340 | s->s_root = d_make_root(root); |
341 | if (!s->s_root) | |
db2c246a | 342 | return -ENOMEM; |
8d9e46d8 | 343 | s->s_d_op = ctx->dops; |
31d6d5ce | 344 | return 0; |
db2c246a | 345 | } |
8d9e46d8 | 346 | |
db2c246a DH |
347 | static int pseudo_fs_get_tree(struct fs_context *fc) |
348 | { | |
2ac295d4 | 349 | return get_tree_nodev(fc, pseudo_fs_fill_super); |
31d6d5ce DH |
350 | } |
351 | ||
352 | static void pseudo_fs_free(struct fs_context *fc) | |
353 | { | |
354 | kfree(fc->fs_private); | |
355 | } | |
356 | ||
357 | static const struct fs_context_operations pseudo_fs_context_ops = { | |
358 | .free = pseudo_fs_free, | |
359 | .get_tree = pseudo_fs_get_tree, | |
360 | }; | |
361 | ||
362 | /* | |
363 | * Common helper for pseudo-filesystems (sockfs, pipefs, bdev - stuff that | |
364 | * will never be mountable) | |
365 | */ | |
366 | struct pseudo_fs_context *init_pseudo(struct fs_context *fc, | |
367 | unsigned long magic) | |
368 | { | |
369 | struct pseudo_fs_context *ctx; | |
370 | ||
371 | ctx = kzalloc(sizeof(struct pseudo_fs_context), GFP_KERNEL); | |
372 | if (likely(ctx)) { | |
373 | ctx->magic = magic; | |
374 | fc->fs_private = ctx; | |
375 | fc->ops = &pseudo_fs_context_ops; | |
db2c246a DH |
376 | fc->sb_flags |= SB_NOUSER; |
377 | fc->global = true; | |
1da177e4 | 378 | } |
31d6d5ce | 379 | return ctx; |
1da177e4 | 380 | } |
31d6d5ce | 381 | EXPORT_SYMBOL(init_pseudo); |
1da177e4 | 382 | |
20955e89 SB |
383 | int simple_open(struct inode *inode, struct file *file) |
384 | { | |
385 | if (inode->i_private) | |
386 | file->private_data = inode->i_private; | |
387 | return 0; | |
388 | } | |
12f38872 | 389 | EXPORT_SYMBOL(simple_open); |
20955e89 | 390 | |
1da177e4 LT |
391 | int simple_link(struct dentry *old_dentry, struct inode *dir, struct dentry *dentry) |
392 | { | |
dea655c2 | 393 | struct inode *inode = d_inode(old_dentry); |
1da177e4 | 394 | |
078cd827 | 395 | inode->i_ctime = dir->i_ctime = dir->i_mtime = current_time(inode); |
d8c76e6f | 396 | inc_nlink(inode); |
7de9c6ee | 397 | ihold(inode); |
1da177e4 LT |
398 | dget(dentry); |
399 | d_instantiate(dentry, inode); | |
400 | return 0; | |
401 | } | |
12f38872 | 402 | EXPORT_SYMBOL(simple_link); |
1da177e4 | 403 | |
1da177e4 LT |
404 | int simple_empty(struct dentry *dentry) |
405 | { | |
406 | struct dentry *child; | |
407 | int ret = 0; | |
408 | ||
2fd6b7f5 | 409 | spin_lock(&dentry->d_lock); |
946e51f2 | 410 | list_for_each_entry(child, &dentry->d_subdirs, d_child) { |
da502956 NP |
411 | spin_lock_nested(&child->d_lock, DENTRY_D_LOCK_NESTED); |
412 | if (simple_positive(child)) { | |
413 | spin_unlock(&child->d_lock); | |
1da177e4 | 414 | goto out; |
da502956 NP |
415 | } |
416 | spin_unlock(&child->d_lock); | |
417 | } | |
1da177e4 LT |
418 | ret = 1; |
419 | out: | |
2fd6b7f5 | 420 | spin_unlock(&dentry->d_lock); |
1da177e4 LT |
421 | return ret; |
422 | } | |
12f38872 | 423 | EXPORT_SYMBOL(simple_empty); |
1da177e4 LT |
424 | |
425 | int simple_unlink(struct inode *dir, struct dentry *dentry) | |
426 | { | |
dea655c2 | 427 | struct inode *inode = d_inode(dentry); |
1da177e4 | 428 | |
078cd827 | 429 | inode->i_ctime = dir->i_ctime = dir->i_mtime = current_time(inode); |
9a53c3a7 | 430 | drop_nlink(inode); |
1da177e4 LT |
431 | dput(dentry); |
432 | return 0; | |
433 | } | |
12f38872 | 434 | EXPORT_SYMBOL(simple_unlink); |
1da177e4 LT |
435 | |
436 | int simple_rmdir(struct inode *dir, struct dentry *dentry) | |
437 | { | |
438 | if (!simple_empty(dentry)) | |
439 | return -ENOTEMPTY; | |
440 | ||
dea655c2 | 441 | drop_nlink(d_inode(dentry)); |
1da177e4 | 442 | simple_unlink(dir, dentry); |
9a53c3a7 | 443 | drop_nlink(dir); |
1da177e4 LT |
444 | return 0; |
445 | } | |
12f38872 | 446 | EXPORT_SYMBOL(simple_rmdir); |
1da177e4 LT |
447 | |
448 | int simple_rename(struct inode *old_dir, struct dentry *old_dentry, | |
e0e0be8a MS |
449 | struct inode *new_dir, struct dentry *new_dentry, |
450 | unsigned int flags) | |
1da177e4 | 451 | { |
dea655c2 | 452 | struct inode *inode = d_inode(old_dentry); |
e36cb0b8 | 453 | int they_are_dirs = d_is_dir(old_dentry); |
1da177e4 | 454 | |
e0e0be8a MS |
455 | if (flags & ~RENAME_NOREPLACE) |
456 | return -EINVAL; | |
457 | ||
1da177e4 LT |
458 | if (!simple_empty(new_dentry)) |
459 | return -ENOTEMPTY; | |
460 | ||
dea655c2 | 461 | if (d_really_is_positive(new_dentry)) { |
1da177e4 | 462 | simple_unlink(new_dir, new_dentry); |
841590ce | 463 | if (they_are_dirs) { |
dea655c2 | 464 | drop_nlink(d_inode(new_dentry)); |
9a53c3a7 | 465 | drop_nlink(old_dir); |
841590ce | 466 | } |
1da177e4 | 467 | } else if (they_are_dirs) { |
9a53c3a7 | 468 | drop_nlink(old_dir); |
d8c76e6f | 469 | inc_nlink(new_dir); |
1da177e4 LT |
470 | } |
471 | ||
472 | old_dir->i_ctime = old_dir->i_mtime = new_dir->i_ctime = | |
078cd827 | 473 | new_dir->i_mtime = inode->i_ctime = current_time(old_dir); |
1da177e4 LT |
474 | |
475 | return 0; | |
476 | } | |
12f38872 | 477 | EXPORT_SYMBOL(simple_rename); |
1da177e4 | 478 | |
7bb46a67 | 479 | /** |
eef2380c | 480 | * simple_setattr - setattr for simple filesystem |
7bb46a67 NP |
481 | * @dentry: dentry |
482 | * @iattr: iattr structure | |
483 | * | |
484 | * Returns 0 on success, -error on failure. | |
485 | * | |
eef2380c CH |
486 | * simple_setattr is a simple ->setattr implementation without a proper |
487 | * implementation of size changes. | |
488 | * | |
489 | * It can either be used for in-memory filesystems or special files | |
490 | * on simple regular filesystems. Anything that needs to change on-disk | |
491 | * or wire state on size changes needs its own setattr method. | |
7bb46a67 NP |
492 | */ |
493 | int simple_setattr(struct dentry *dentry, struct iattr *iattr) | |
494 | { | |
dea655c2 | 495 | struct inode *inode = d_inode(dentry); |
7bb46a67 NP |
496 | int error; |
497 | ||
31051c85 | 498 | error = setattr_prepare(dentry, iattr); |
7bb46a67 NP |
499 | if (error) |
500 | return error; | |
501 | ||
2c27c65e CH |
502 | if (iattr->ia_valid & ATTR_SIZE) |
503 | truncate_setsize(inode, iattr->ia_size); | |
6a1a90ad | 504 | setattr_copy(inode, iattr); |
eef2380c CH |
505 | mark_inode_dirty(inode); |
506 | return 0; | |
7bb46a67 NP |
507 | } |
508 | EXPORT_SYMBOL(simple_setattr); | |
509 | ||
1da177e4 LT |
510 | int simple_readpage(struct file *file, struct page *page) |
511 | { | |
c0d92cbc | 512 | clear_highpage(page); |
1da177e4 LT |
513 | flush_dcache_page(page); |
514 | SetPageUptodate(page); | |
1da177e4 LT |
515 | unlock_page(page); |
516 | return 0; | |
517 | } | |
12f38872 | 518 | EXPORT_SYMBOL(simple_readpage); |
1da177e4 | 519 | |
afddba49 NP |
520 | int simple_write_begin(struct file *file, struct address_space *mapping, |
521 | loff_t pos, unsigned len, unsigned flags, | |
522 | struct page **pagep, void **fsdata) | |
523 | { | |
524 | struct page *page; | |
525 | pgoff_t index; | |
afddba49 | 526 | |
09cbfeaf | 527 | index = pos >> PAGE_SHIFT; |
afddba49 | 528 | |
54566b2c | 529 | page = grab_cache_page_write_begin(mapping, index, flags); |
afddba49 NP |
530 | if (!page) |
531 | return -ENOMEM; | |
532 | ||
533 | *pagep = page; | |
534 | ||
09cbfeaf KS |
535 | if (!PageUptodate(page) && (len != PAGE_SIZE)) { |
536 | unsigned from = pos & (PAGE_SIZE - 1); | |
193cf4b9 | 537 | |
09cbfeaf | 538 | zero_user_segments(page, 0, from, from + len, PAGE_SIZE); |
193cf4b9 BH |
539 | } |
540 | return 0; | |
afddba49 | 541 | } |
12f38872 | 542 | EXPORT_SYMBOL(simple_write_begin); |
afddba49 | 543 | |
ad2a722f BH |
544 | /** |
545 | * simple_write_end - .write_end helper for non-block-device FSes | |
8e88bfba | 546 | * @file: See .write_end of address_space_operations |
ad2a722f BH |
547 | * @mapping: " |
548 | * @pos: " | |
549 | * @len: " | |
550 | * @copied: " | |
551 | * @page: " | |
552 | * @fsdata: " | |
553 | * | |
554 | * simple_write_end does the minimum needed for updating a page after writing is | |
555 | * done. It has the same API signature as the .write_end of | |
556 | * address_space_operations vector. So it can just be set onto .write_end for | |
557 | * FSes that don't need any other processing. i_mutex is assumed to be held. | |
558 | * Block based filesystems should use generic_write_end(). | |
559 | * NOTE: Even though i_size might get updated by this function, mark_inode_dirty | |
560 | * is not called, so a filesystem that actually does store data in .write_inode | |
561 | * should extend on what's done here with a call to mark_inode_dirty() in the | |
562 | * case that i_size has changed. | |
04fff641 AV |
563 | * |
564 | * Use *ONLY* with simple_readpage() | |
ad2a722f | 565 | */ |
afddba49 NP |
566 | int simple_write_end(struct file *file, struct address_space *mapping, |
567 | loff_t pos, unsigned len, unsigned copied, | |
568 | struct page *page, void *fsdata) | |
569 | { | |
ad2a722f BH |
570 | struct inode *inode = page->mapping->host; |
571 | loff_t last_pos = pos + copied; | |
afddba49 NP |
572 | |
573 | /* zero the stale part of the page if we did a short copy */ | |
04fff641 AV |
574 | if (!PageUptodate(page)) { |
575 | if (copied < len) { | |
576 | unsigned from = pos & (PAGE_SIZE - 1); | |
afddba49 | 577 | |
04fff641 AV |
578 | zero_user(page, from + copied, len - copied); |
579 | } | |
ad2a722f | 580 | SetPageUptodate(page); |
04fff641 | 581 | } |
ad2a722f BH |
582 | /* |
583 | * No need to use i_size_read() here, the i_size | |
584 | * cannot change under us because we hold the i_mutex. | |
585 | */ | |
586 | if (last_pos > inode->i_size) | |
587 | i_size_write(inode, last_pos); | |
afddba49 | 588 | |
ad2a722f | 589 | set_page_dirty(page); |
afddba49 | 590 | unlock_page(page); |
09cbfeaf | 591 | put_page(page); |
afddba49 NP |
592 | |
593 | return copied; | |
594 | } | |
12f38872 | 595 | EXPORT_SYMBOL(simple_write_end); |
afddba49 | 596 | |
1a1c9bb4 JL |
597 | /* |
598 | * the inodes created here are not hashed. If you use iunique to generate | |
599 | * unique inode values later for this filesystem, then you must take care | |
600 | * to pass it an appropriate max_reserved value to avoid collisions. | |
601 | */ | |
7d683a09 | 602 | int simple_fill_super(struct super_block *s, unsigned long magic, |
cda37124 | 603 | const struct tree_descr *files) |
1da177e4 | 604 | { |
1da177e4 LT |
605 | struct inode *inode; |
606 | struct dentry *root; | |
607 | struct dentry *dentry; | |
608 | int i; | |
609 | ||
09cbfeaf KS |
610 | s->s_blocksize = PAGE_SIZE; |
611 | s->s_blocksize_bits = PAGE_SHIFT; | |
1da177e4 | 612 | s->s_magic = magic; |
759b9775 | 613 | s->s_op = &simple_super_operations; |
1da177e4 LT |
614 | s->s_time_gran = 1; |
615 | ||
616 | inode = new_inode(s); | |
617 | if (!inode) | |
618 | return -ENOMEM; | |
1a1c9bb4 JL |
619 | /* |
620 | * because the root inode is 1, the files array must not contain an | |
621 | * entry at index 1 | |
622 | */ | |
623 | inode->i_ino = 1; | |
1da177e4 | 624 | inode->i_mode = S_IFDIR | 0755; |
078cd827 | 625 | inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode); |
1da177e4 LT |
626 | inode->i_op = &simple_dir_inode_operations; |
627 | inode->i_fop = &simple_dir_operations; | |
bfe86848 | 628 | set_nlink(inode, 2); |
48fde701 AV |
629 | root = d_make_root(inode); |
630 | if (!root) | |
1da177e4 | 631 | return -ENOMEM; |
1da177e4 LT |
632 | for (i = 0; !files->name || files->name[0]; i++, files++) { |
633 | if (!files->name) | |
634 | continue; | |
1a1c9bb4 JL |
635 | |
636 | /* warn if it tries to conflict with the root inode */ | |
637 | if (unlikely(i == 1)) | |
638 | printk(KERN_WARNING "%s: %s passed in a files array" | |
639 | "with an index of 1!\n", __func__, | |
640 | s->s_type->name); | |
641 | ||
1da177e4 LT |
642 | dentry = d_alloc_name(root, files->name); |
643 | if (!dentry) | |
644 | goto out; | |
645 | inode = new_inode(s); | |
32096ea1 KK |
646 | if (!inode) { |
647 | dput(dentry); | |
1da177e4 | 648 | goto out; |
32096ea1 | 649 | } |
1da177e4 | 650 | inode->i_mode = S_IFREG | files->mode; |
078cd827 | 651 | inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode); |
1da177e4 LT |
652 | inode->i_fop = files->ops; |
653 | inode->i_ino = i; | |
654 | d_add(dentry, inode); | |
655 | } | |
656 | s->s_root = root; | |
657 | return 0; | |
658 | out: | |
659 | d_genocide(root); | |
640946f2 | 660 | shrink_dcache_parent(root); |
1da177e4 LT |
661 | dput(root); |
662 | return -ENOMEM; | |
663 | } | |
12f38872 | 664 | EXPORT_SYMBOL(simple_fill_super); |
1da177e4 LT |
665 | |
666 | static DEFINE_SPINLOCK(pin_fs_lock); | |
667 | ||
1f5ce9e9 | 668 | int simple_pin_fs(struct file_system_type *type, struct vfsmount **mount, int *count) |
1da177e4 LT |
669 | { |
670 | struct vfsmount *mnt = NULL; | |
671 | spin_lock(&pin_fs_lock); | |
672 | if (unlikely(!*mount)) { | |
673 | spin_unlock(&pin_fs_lock); | |
1751e8a6 | 674 | mnt = vfs_kern_mount(type, SB_KERNMOUNT, type->name, NULL); |
1da177e4 LT |
675 | if (IS_ERR(mnt)) |
676 | return PTR_ERR(mnt); | |
677 | spin_lock(&pin_fs_lock); | |
678 | if (!*mount) | |
679 | *mount = mnt; | |
680 | } | |
681 | mntget(*mount); | |
682 | ++*count; | |
683 | spin_unlock(&pin_fs_lock); | |
684 | mntput(mnt); | |
685 | return 0; | |
686 | } | |
12f38872 | 687 | EXPORT_SYMBOL(simple_pin_fs); |
1da177e4 LT |
688 | |
689 | void simple_release_fs(struct vfsmount **mount, int *count) | |
690 | { | |
691 | struct vfsmount *mnt; | |
692 | spin_lock(&pin_fs_lock); | |
693 | mnt = *mount; | |
694 | if (!--*count) | |
695 | *mount = NULL; | |
696 | spin_unlock(&pin_fs_lock); | |
697 | mntput(mnt); | |
698 | } | |
12f38872 | 699 | EXPORT_SYMBOL(simple_release_fs); |
1da177e4 | 700 | |
6d1029b5 AM |
701 | /** |
702 | * simple_read_from_buffer - copy data from the buffer to user space | |
703 | * @to: the user space buffer to read to | |
704 | * @count: the maximum number of bytes to read | |
705 | * @ppos: the current position in the buffer | |
706 | * @from: the buffer to read from | |
707 | * @available: the size of the buffer | |
708 | * | |
709 | * The simple_read_from_buffer() function reads up to @count bytes from the | |
710 | * buffer @from at offset @ppos into the user space address starting at @to. | |
711 | * | |
712 | * On success, the number of bytes read is returned and the offset @ppos is | |
713 | * advanced by this number, or negative value is returned on error. | |
714 | **/ | |
1da177e4 LT |
715 | ssize_t simple_read_from_buffer(void __user *to, size_t count, loff_t *ppos, |
716 | const void *from, size_t available) | |
717 | { | |
718 | loff_t pos = *ppos; | |
14be2746 SR |
719 | size_t ret; |
720 | ||
1da177e4 LT |
721 | if (pos < 0) |
722 | return -EINVAL; | |
14be2746 | 723 | if (pos >= available || !count) |
1da177e4 LT |
724 | return 0; |
725 | if (count > available - pos) | |
726 | count = available - pos; | |
14be2746 SR |
727 | ret = copy_to_user(to, from + pos, count); |
728 | if (ret == count) | |
1da177e4 | 729 | return -EFAULT; |
14be2746 | 730 | count -= ret; |
1da177e4 LT |
731 | *ppos = pos + count; |
732 | return count; | |
733 | } | |
12f38872 | 734 | EXPORT_SYMBOL(simple_read_from_buffer); |
1da177e4 | 735 | |
6a727b43 JS |
736 | /** |
737 | * simple_write_to_buffer - copy data from user space to the buffer | |
738 | * @to: the buffer to write to | |
739 | * @available: the size of the buffer | |
740 | * @ppos: the current position in the buffer | |
741 | * @from: the user space buffer to read from | |
742 | * @count: the maximum number of bytes to read | |
743 | * | |
744 | * The simple_write_to_buffer() function reads up to @count bytes from the user | |
745 | * space address starting at @from into the buffer @to at offset @ppos. | |
746 | * | |
747 | * On success, the number of bytes written is returned and the offset @ppos is | |
748 | * advanced by this number, or negative value is returned on error. | |
749 | **/ | |
750 | ssize_t simple_write_to_buffer(void *to, size_t available, loff_t *ppos, | |
751 | const void __user *from, size_t count) | |
752 | { | |
753 | loff_t pos = *ppos; | |
754 | size_t res; | |
755 | ||
756 | if (pos < 0) | |
757 | return -EINVAL; | |
758 | if (pos >= available || !count) | |
759 | return 0; | |
760 | if (count > available - pos) | |
761 | count = available - pos; | |
762 | res = copy_from_user(to + pos, from, count); | |
763 | if (res == count) | |
764 | return -EFAULT; | |
765 | count -= res; | |
766 | *ppos = pos + count; | |
767 | return count; | |
768 | } | |
12f38872 | 769 | EXPORT_SYMBOL(simple_write_to_buffer); |
6a727b43 | 770 | |
6d1029b5 AM |
771 | /** |
772 | * memory_read_from_buffer - copy data from the buffer | |
773 | * @to: the kernel space buffer to read to | |
774 | * @count: the maximum number of bytes to read | |
775 | * @ppos: the current position in the buffer | |
776 | * @from: the buffer to read from | |
777 | * @available: the size of the buffer | |
778 | * | |
779 | * The memory_read_from_buffer() function reads up to @count bytes from the | |
780 | * buffer @from at offset @ppos into the kernel space address starting at @to. | |
781 | * | |
782 | * On success, the number of bytes read is returned and the offset @ppos is | |
783 | * advanced by this number, or negative value is returned on error. | |
784 | **/ | |
93b07113 AM |
785 | ssize_t memory_read_from_buffer(void *to, size_t count, loff_t *ppos, |
786 | const void *from, size_t available) | |
787 | { | |
788 | loff_t pos = *ppos; | |
789 | ||
790 | if (pos < 0) | |
791 | return -EINVAL; | |
792 | if (pos >= available) | |
793 | return 0; | |
794 | if (count > available - pos) | |
795 | count = available - pos; | |
796 | memcpy(to, from + pos, count); | |
797 | *ppos = pos + count; | |
798 | ||
799 | return count; | |
800 | } | |
12f38872 | 801 | EXPORT_SYMBOL(memory_read_from_buffer); |
93b07113 | 802 | |
1da177e4 LT |
803 | /* |
804 | * Transaction based IO. | |
805 | * The file expects a single write which triggers the transaction, and then | |
806 | * possibly a read which collects the result - which is stored in a | |
807 | * file-local buffer. | |
808 | */ | |
76791ab2 IM |
809 | |
810 | void simple_transaction_set(struct file *file, size_t n) | |
811 | { | |
812 | struct simple_transaction_argresp *ar = file->private_data; | |
813 | ||
814 | BUG_ON(n > SIMPLE_TRANSACTION_LIMIT); | |
815 | ||
816 | /* | |
817 | * The barrier ensures that ar->size will really remain zero until | |
818 | * ar->data is ready for reading. | |
819 | */ | |
820 | smp_mb(); | |
821 | ar->size = n; | |
822 | } | |
12f38872 | 823 | EXPORT_SYMBOL(simple_transaction_set); |
76791ab2 | 824 | |
1da177e4 LT |
825 | char *simple_transaction_get(struct file *file, const char __user *buf, size_t size) |
826 | { | |
827 | struct simple_transaction_argresp *ar; | |
828 | static DEFINE_SPINLOCK(simple_transaction_lock); | |
829 | ||
830 | if (size > SIMPLE_TRANSACTION_LIMIT - 1) | |
831 | return ERR_PTR(-EFBIG); | |
832 | ||
833 | ar = (struct simple_transaction_argresp *)get_zeroed_page(GFP_KERNEL); | |
834 | if (!ar) | |
835 | return ERR_PTR(-ENOMEM); | |
836 | ||
837 | spin_lock(&simple_transaction_lock); | |
838 | ||
839 | /* only one write allowed per open */ | |
840 | if (file->private_data) { | |
841 | spin_unlock(&simple_transaction_lock); | |
842 | free_page((unsigned long)ar); | |
843 | return ERR_PTR(-EBUSY); | |
844 | } | |
845 | ||
846 | file->private_data = ar; | |
847 | ||
848 | spin_unlock(&simple_transaction_lock); | |
849 | ||
850 | if (copy_from_user(ar->data, buf, size)) | |
851 | return ERR_PTR(-EFAULT); | |
852 | ||
853 | return ar->data; | |
854 | } | |
12f38872 | 855 | EXPORT_SYMBOL(simple_transaction_get); |
1da177e4 LT |
856 | |
857 | ssize_t simple_transaction_read(struct file *file, char __user *buf, size_t size, loff_t *pos) | |
858 | { | |
859 | struct simple_transaction_argresp *ar = file->private_data; | |
860 | ||
861 | if (!ar) | |
862 | return 0; | |
863 | return simple_read_from_buffer(buf, size, pos, ar->data, ar->size); | |
864 | } | |
12f38872 | 865 | EXPORT_SYMBOL(simple_transaction_read); |
1da177e4 LT |
866 | |
867 | int simple_transaction_release(struct inode *inode, struct file *file) | |
868 | { | |
869 | free_page((unsigned long)file->private_data); | |
870 | return 0; | |
871 | } | |
12f38872 | 872 | EXPORT_SYMBOL(simple_transaction_release); |
1da177e4 | 873 | |
acaefc25 AB |
874 | /* Simple attribute files */ |
875 | ||
876 | struct simple_attr { | |
8b88b099 CH |
877 | int (*get)(void *, u64 *); |
878 | int (*set)(void *, u64); | |
acaefc25 AB |
879 | char get_buf[24]; /* enough to store a u64 and "\n\0" */ |
880 | char set_buf[24]; | |
881 | void *data; | |
882 | const char *fmt; /* format for read operation */ | |
7cf34c76 | 883 | struct mutex mutex; /* protects access to these buffers */ |
acaefc25 AB |
884 | }; |
885 | ||
886 | /* simple_attr_open is called by an actual attribute open file operation | |
887 | * to set the attribute specific access operations. */ | |
888 | int simple_attr_open(struct inode *inode, struct file *file, | |
8b88b099 | 889 | int (*get)(void *, u64 *), int (*set)(void *, u64), |
acaefc25 AB |
890 | const char *fmt) |
891 | { | |
892 | struct simple_attr *attr; | |
893 | ||
a65cab7d | 894 | attr = kzalloc(sizeof(*attr), GFP_KERNEL); |
acaefc25 AB |
895 | if (!attr) |
896 | return -ENOMEM; | |
897 | ||
898 | attr->get = get; | |
899 | attr->set = set; | |
8e18e294 | 900 | attr->data = inode->i_private; |
acaefc25 | 901 | attr->fmt = fmt; |
7cf34c76 | 902 | mutex_init(&attr->mutex); |
acaefc25 AB |
903 | |
904 | file->private_data = attr; | |
905 | ||
906 | return nonseekable_open(inode, file); | |
907 | } | |
12f38872 | 908 | EXPORT_SYMBOL_GPL(simple_attr_open); |
acaefc25 | 909 | |
74bedc4d | 910 | int simple_attr_release(struct inode *inode, struct file *file) |
acaefc25 AB |
911 | { |
912 | kfree(file->private_data); | |
913 | return 0; | |
914 | } | |
12f38872 | 915 | EXPORT_SYMBOL_GPL(simple_attr_release); /* GPL-only? This? Really? */ |
acaefc25 AB |
916 | |
917 | /* read from the buffer that is filled with the get function */ | |
918 | ssize_t simple_attr_read(struct file *file, char __user *buf, | |
919 | size_t len, loff_t *ppos) | |
920 | { | |
921 | struct simple_attr *attr; | |
922 | size_t size; | |
923 | ssize_t ret; | |
924 | ||
925 | attr = file->private_data; | |
926 | ||
927 | if (!attr->get) | |
928 | return -EACCES; | |
929 | ||
9261303a CH |
930 | ret = mutex_lock_interruptible(&attr->mutex); |
931 | if (ret) | |
932 | return ret; | |
933 | ||
a65cab7d EB |
934 | if (*ppos && attr->get_buf[0]) { |
935 | /* continued read */ | |
acaefc25 | 936 | size = strlen(attr->get_buf); |
a65cab7d EB |
937 | } else { |
938 | /* first read */ | |
8b88b099 CH |
939 | u64 val; |
940 | ret = attr->get(attr->data, &val); | |
941 | if (ret) | |
942 | goto out; | |
943 | ||
acaefc25 | 944 | size = scnprintf(attr->get_buf, sizeof(attr->get_buf), |
8b88b099 CH |
945 | attr->fmt, (unsigned long long)val); |
946 | } | |
acaefc25 AB |
947 | |
948 | ret = simple_read_from_buffer(buf, len, ppos, attr->get_buf, size); | |
8b88b099 | 949 | out: |
7cf34c76 | 950 | mutex_unlock(&attr->mutex); |
acaefc25 AB |
951 | return ret; |
952 | } | |
12f38872 | 953 | EXPORT_SYMBOL_GPL(simple_attr_read); |
acaefc25 AB |
954 | |
955 | /* interpret the buffer as a number to call the set function with */ | |
956 | ssize_t simple_attr_write(struct file *file, const char __user *buf, | |
957 | size_t len, loff_t *ppos) | |
958 | { | |
959 | struct simple_attr *attr; | |
960 | u64 val; | |
961 | size_t size; | |
962 | ssize_t ret; | |
963 | ||
964 | attr = file->private_data; | |
acaefc25 AB |
965 | if (!attr->set) |
966 | return -EACCES; | |
967 | ||
9261303a CH |
968 | ret = mutex_lock_interruptible(&attr->mutex); |
969 | if (ret) | |
970 | return ret; | |
971 | ||
acaefc25 AB |
972 | ret = -EFAULT; |
973 | size = min(sizeof(attr->set_buf) - 1, len); | |
974 | if (copy_from_user(attr->set_buf, buf, size)) | |
975 | goto out; | |
976 | ||
acaefc25 | 977 | attr->set_buf[size] = '\0'; |
f7b88631 | 978 | val = simple_strtoll(attr->set_buf, NULL, 0); |
05cc0cee WF |
979 | ret = attr->set(attr->data, val); |
980 | if (ret == 0) | |
981 | ret = len; /* on success, claim we got the whole input */ | |
acaefc25 | 982 | out: |
7cf34c76 | 983 | mutex_unlock(&attr->mutex); |
acaefc25 AB |
984 | return ret; |
985 | } | |
12f38872 | 986 | EXPORT_SYMBOL_GPL(simple_attr_write); |
acaefc25 | 987 | |
2596110a CH |
988 | /** |
989 | * generic_fh_to_dentry - generic helper for the fh_to_dentry export operation | |
990 | * @sb: filesystem to do the file handle conversion on | |
991 | * @fid: file handle to convert | |
992 | * @fh_len: length of the file handle in bytes | |
993 | * @fh_type: type of file handle | |
994 | * @get_inode: filesystem callback to retrieve inode | |
995 | * | |
996 | * This function decodes @fid as long as it has one of the well-known | |
997 | * Linux filehandle types and calls @get_inode on it to retrieve the | |
998 | * inode for the object specified in the file handle. | |
999 | */ | |
1000 | struct dentry *generic_fh_to_dentry(struct super_block *sb, struct fid *fid, | |
1001 | int fh_len, int fh_type, struct inode *(*get_inode) | |
1002 | (struct super_block *sb, u64 ino, u32 gen)) | |
1003 | { | |
1004 | struct inode *inode = NULL; | |
1005 | ||
1006 | if (fh_len < 2) | |
1007 | return NULL; | |
1008 | ||
1009 | switch (fh_type) { | |
1010 | case FILEID_INO32_GEN: | |
1011 | case FILEID_INO32_GEN_PARENT: | |
1012 | inode = get_inode(sb, fid->i32.ino, fid->i32.gen); | |
1013 | break; | |
1014 | } | |
1015 | ||
4ea3ada2 | 1016 | return d_obtain_alias(inode); |
2596110a CH |
1017 | } |
1018 | EXPORT_SYMBOL_GPL(generic_fh_to_dentry); | |
1019 | ||
1020 | /** | |
ca186830 | 1021 | * generic_fh_to_parent - generic helper for the fh_to_parent export operation |
2596110a CH |
1022 | * @sb: filesystem to do the file handle conversion on |
1023 | * @fid: file handle to convert | |
1024 | * @fh_len: length of the file handle in bytes | |
1025 | * @fh_type: type of file handle | |
1026 | * @get_inode: filesystem callback to retrieve inode | |
1027 | * | |
1028 | * This function decodes @fid as long as it has one of the well-known | |
1029 | * Linux filehandle types and calls @get_inode on it to retrieve the | |
1030 | * inode for the _parent_ object specified in the file handle if it | |
1031 | * is specified in the file handle, or NULL otherwise. | |
1032 | */ | |
1033 | struct dentry *generic_fh_to_parent(struct super_block *sb, struct fid *fid, | |
1034 | int fh_len, int fh_type, struct inode *(*get_inode) | |
1035 | (struct super_block *sb, u64 ino, u32 gen)) | |
1036 | { | |
1037 | struct inode *inode = NULL; | |
1038 | ||
1039 | if (fh_len <= 2) | |
1040 | return NULL; | |
1041 | ||
1042 | switch (fh_type) { | |
1043 | case FILEID_INO32_GEN_PARENT: | |
1044 | inode = get_inode(sb, fid->i32.parent_ino, | |
1045 | (fh_len > 3 ? fid->i32.parent_gen : 0)); | |
1046 | break; | |
1047 | } | |
1048 | ||
4ea3ada2 | 1049 | return d_obtain_alias(inode); |
2596110a CH |
1050 | } |
1051 | EXPORT_SYMBOL_GPL(generic_fh_to_parent); | |
1052 | ||
1b061d92 | 1053 | /** |
ac13a829 FF |
1054 | * __generic_file_fsync - generic fsync implementation for simple filesystems |
1055 | * | |
1b061d92 | 1056 | * @file: file to synchronize |
ac13a829 FF |
1057 | * @start: start offset in bytes |
1058 | * @end: end offset in bytes (inclusive) | |
1b061d92 CH |
1059 | * @datasync: only synchronize essential metadata if true |
1060 | * | |
1061 | * This is a generic implementation of the fsync method for simple | |
1062 | * filesystems which track all non-inode metadata in the buffers list | |
1063 | * hanging off the address_space structure. | |
1064 | */ | |
ac13a829 FF |
1065 | int __generic_file_fsync(struct file *file, loff_t start, loff_t end, |
1066 | int datasync) | |
d5aacad5 | 1067 | { |
7ea80859 | 1068 | struct inode *inode = file->f_mapping->host; |
d5aacad5 AV |
1069 | int err; |
1070 | int ret; | |
1071 | ||
383aa543 | 1072 | err = file_write_and_wait_range(file, start, end); |
02c24a82 JB |
1073 | if (err) |
1074 | return err; | |
1075 | ||
5955102c | 1076 | inode_lock(inode); |
d5aacad5 | 1077 | ret = sync_mapping_buffers(inode->i_mapping); |
0ae45f63 | 1078 | if (!(inode->i_state & I_DIRTY_ALL)) |
02c24a82 | 1079 | goto out; |
d5aacad5 | 1080 | if (datasync && !(inode->i_state & I_DIRTY_DATASYNC)) |
02c24a82 | 1081 | goto out; |
d5aacad5 | 1082 | |
c3765016 | 1083 | err = sync_inode_metadata(inode, 1); |
d5aacad5 AV |
1084 | if (ret == 0) |
1085 | ret = err; | |
ac13a829 | 1086 | |
02c24a82 | 1087 | out: |
5955102c | 1088 | inode_unlock(inode); |
383aa543 JL |
1089 | /* check and advance again to catch errors after syncing out buffers */ |
1090 | err = file_check_and_advance_wb_err(file); | |
1091 | if (ret == 0) | |
1092 | ret = err; | |
1093 | return ret; | |
d5aacad5 | 1094 | } |
ac13a829 FF |
1095 | EXPORT_SYMBOL(__generic_file_fsync); |
1096 | ||
1097 | /** | |
1098 | * generic_file_fsync - generic fsync implementation for simple filesystems | |
1099 | * with flush | |
1100 | * @file: file to synchronize | |
1101 | * @start: start offset in bytes | |
1102 | * @end: end offset in bytes (inclusive) | |
1103 | * @datasync: only synchronize essential metadata if true | |
1104 | * | |
1105 | */ | |
1106 | ||
1107 | int generic_file_fsync(struct file *file, loff_t start, loff_t end, | |
1108 | int datasync) | |
1109 | { | |
1110 | struct inode *inode = file->f_mapping->host; | |
1111 | int err; | |
1112 | ||
1113 | err = __generic_file_fsync(file, start, end, datasync); | |
1114 | if (err) | |
1115 | return err; | |
1116 | return blkdev_issue_flush(inode->i_sb->s_bdev, GFP_KERNEL, NULL); | |
1117 | } | |
1b061d92 CH |
1118 | EXPORT_SYMBOL(generic_file_fsync); |
1119 | ||
30ca22c7 PL |
1120 | /** |
1121 | * generic_check_addressable - Check addressability of file system | |
1122 | * @blocksize_bits: log of file system block size | |
1123 | * @num_blocks: number of blocks in file system | |
1124 | * | |
1125 | * Determine whether a file system with @num_blocks blocks (and a | |
1126 | * block size of 2**@blocksize_bits) is addressable by the sector_t | |
1127 | * and page cache of the system. Return 0 if so and -EFBIG otherwise. | |
1128 | */ | |
1129 | int generic_check_addressable(unsigned blocksize_bits, u64 num_blocks) | |
1130 | { | |
1131 | u64 last_fs_block = num_blocks - 1; | |
a33f13ef | 1132 | u64 last_fs_page = |
09cbfeaf | 1133 | last_fs_block >> (PAGE_SHIFT - blocksize_bits); |
30ca22c7 PL |
1134 | |
1135 | if (unlikely(num_blocks == 0)) | |
1136 | return 0; | |
1137 | ||
09cbfeaf | 1138 | if ((blocksize_bits < 9) || (blocksize_bits > PAGE_SHIFT)) |
30ca22c7 PL |
1139 | return -EINVAL; |
1140 | ||
a33f13ef JB |
1141 | if ((last_fs_block > (sector_t)(~0ULL) >> (blocksize_bits - 9)) || |
1142 | (last_fs_page > (pgoff_t)(~0ULL))) { | |
30ca22c7 PL |
1143 | return -EFBIG; |
1144 | } | |
1145 | return 0; | |
1146 | } | |
1147 | EXPORT_SYMBOL(generic_check_addressable); | |
1148 | ||
1b061d92 CH |
1149 | /* |
1150 | * No-op implementation of ->fsync for in-memory filesystems. | |
1151 | */ | |
02c24a82 | 1152 | int noop_fsync(struct file *file, loff_t start, loff_t end, int datasync) |
1b061d92 CH |
1153 | { |
1154 | return 0; | |
1155 | } | |
1b061d92 | 1156 | EXPORT_SYMBOL(noop_fsync); |
87dc800b | 1157 | |
f44c7763 DW |
1158 | int noop_set_page_dirty(struct page *page) |
1159 | { | |
1160 | /* | |
1161 | * Unlike __set_page_dirty_no_writeback that handles dirty page | |
1162 | * tracking in the page object, dax does all dirty tracking in | |
1163 | * the inode address_space in response to mkwrite faults. In the | |
1164 | * dax case we only need to worry about potentially dirty CPU | |
1165 | * caches, not dirty page cache pages to write back. | |
1166 | * | |
1167 | * This callback is defined to prevent fallback to | |
1168 | * __set_page_dirty_buffers() in set_page_dirty(). | |
1169 | */ | |
1170 | return 0; | |
1171 | } | |
1172 | EXPORT_SYMBOL_GPL(noop_set_page_dirty); | |
1173 | ||
1174 | void noop_invalidatepage(struct page *page, unsigned int offset, | |
1175 | unsigned int length) | |
1176 | { | |
1177 | /* | |
1178 | * There is no page cache to invalidate in the dax case, however | |
1179 | * we need this callback defined to prevent falling back to | |
1180 | * block_invalidatepage() in do_invalidatepage(). | |
1181 | */ | |
1182 | } | |
1183 | EXPORT_SYMBOL_GPL(noop_invalidatepage); | |
1184 | ||
1185 | ssize_t noop_direct_IO(struct kiocb *iocb, struct iov_iter *iter) | |
1186 | { | |
1187 | /* | |
1188 | * iomap based filesystems support direct I/O without need for | |
1189 | * this callback. However, it still needs to be set in | |
1190 | * inode->a_ops so that open/fcntl know that direct I/O is | |
1191 | * generally supported. | |
1192 | */ | |
1193 | return -EINVAL; | |
1194 | } | |
1195 | EXPORT_SYMBOL_GPL(noop_direct_IO); | |
1196 | ||
fceef393 AV |
1197 | /* Because kfree isn't assignment-compatible with void(void*) ;-/ */ |
1198 | void kfree_link(void *p) | |
87dc800b | 1199 | { |
fceef393 | 1200 | kfree(p); |
87dc800b | 1201 | } |
fceef393 | 1202 | EXPORT_SYMBOL(kfree_link); |
6987843f AV |
1203 | |
1204 | /* | |
1205 | * nop .set_page_dirty method so that people can use .page_mkwrite on | |
1206 | * anon inodes. | |
1207 | */ | |
1208 | static int anon_set_page_dirty(struct page *page) | |
1209 | { | |
1210 | return 0; | |
1211 | }; | |
1212 | ||
1213 | /* | |
1214 | * A single inode exists for all anon_inode files. Contrary to pipes, | |
1215 | * anon_inode inodes have no associated per-instance data, so we need | |
1216 | * only allocate one of them. | |
1217 | */ | |
1218 | struct inode *alloc_anon_inode(struct super_block *s) | |
1219 | { | |
1220 | static const struct address_space_operations anon_aops = { | |
1221 | .set_page_dirty = anon_set_page_dirty, | |
1222 | }; | |
1223 | struct inode *inode = new_inode_pseudo(s); | |
1224 | ||
1225 | if (!inode) | |
1226 | return ERR_PTR(-ENOMEM); | |
1227 | ||
1228 | inode->i_ino = get_next_ino(); | |
1229 | inode->i_mapping->a_ops = &anon_aops; | |
1230 | ||
1231 | /* | |
1232 | * Mark the inode dirty from the very beginning, | |
1233 | * that way it will never be moved to the dirty | |
1234 | * list because mark_inode_dirty() will think | |
1235 | * that it already _is_ on the dirty list. | |
1236 | */ | |
1237 | inode->i_state = I_DIRTY; | |
1238 | inode->i_mode = S_IRUSR | S_IWUSR; | |
1239 | inode->i_uid = current_fsuid(); | |
1240 | inode->i_gid = current_fsgid(); | |
1241 | inode->i_flags |= S_PRIVATE; | |
078cd827 | 1242 | inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode); |
6987843f AV |
1243 | return inode; |
1244 | } | |
1245 | EXPORT_SYMBOL(alloc_anon_inode); | |
1c994a09 JL |
1246 | |
1247 | /** | |
1248 | * simple_nosetlease - generic helper for prohibiting leases | |
1249 | * @filp: file pointer | |
1250 | * @arg: type of lease to obtain | |
1251 | * @flp: new lease supplied for insertion | |
e6f5c789 | 1252 | * @priv: private data for lm_setup operation |
1c994a09 JL |
1253 | * |
1254 | * Generic helper for filesystems that do not wish to allow leases to be set. | |
1255 | * All arguments are ignored and it just returns -EINVAL. | |
1256 | */ | |
1257 | int | |
e6f5c789 JL |
1258 | simple_nosetlease(struct file *filp, long arg, struct file_lock **flp, |
1259 | void **priv) | |
1c994a09 JL |
1260 | { |
1261 | return -EINVAL; | |
1262 | } | |
1263 | EXPORT_SYMBOL(simple_nosetlease); | |
61ba64fc | 1264 | |
6ee9706a EB |
1265 | /** |
1266 | * simple_get_link - generic helper to get the target of "fast" symlinks | |
1267 | * @dentry: not used here | |
1268 | * @inode: the symlink inode | |
1269 | * @done: not used here | |
1270 | * | |
1271 | * Generic helper for filesystems to use for symlink inodes where a pointer to | |
1272 | * the symlink target is stored in ->i_link. NOTE: this isn't normally called, | |
1273 | * since as an optimization the path lookup code uses any non-NULL ->i_link | |
1274 | * directly, without calling ->get_link(). But ->get_link() still must be set, | |
1275 | * to mark the inode_operations as being for a symlink. | |
1276 | * | |
1277 | * Return: the symlink target | |
1278 | */ | |
6b255391 | 1279 | const char *simple_get_link(struct dentry *dentry, struct inode *inode, |
fceef393 | 1280 | struct delayed_call *done) |
61ba64fc | 1281 | { |
6b255391 | 1282 | return inode->i_link; |
61ba64fc | 1283 | } |
6b255391 | 1284 | EXPORT_SYMBOL(simple_get_link); |
61ba64fc AV |
1285 | |
1286 | const struct inode_operations simple_symlink_inode_operations = { | |
6b255391 | 1287 | .get_link = simple_get_link, |
61ba64fc AV |
1288 | }; |
1289 | EXPORT_SYMBOL(simple_symlink_inode_operations); | |
fbabfd0f EB |
1290 | |
1291 | /* | |
1292 | * Operations for a permanently empty directory. | |
1293 | */ | |
1294 | static struct dentry *empty_dir_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags) | |
1295 | { | |
1296 | return ERR_PTR(-ENOENT); | |
1297 | } | |
1298 | ||
a528d35e DH |
1299 | static int empty_dir_getattr(const struct path *path, struct kstat *stat, |
1300 | u32 request_mask, unsigned int query_flags) | |
fbabfd0f | 1301 | { |
a528d35e | 1302 | struct inode *inode = d_inode(path->dentry); |
fbabfd0f EB |
1303 | generic_fillattr(inode, stat); |
1304 | return 0; | |
1305 | } | |
1306 | ||
1307 | static int empty_dir_setattr(struct dentry *dentry, struct iattr *attr) | |
1308 | { | |
1309 | return -EPERM; | |
1310 | } | |
1311 | ||
fbabfd0f EB |
1312 | static ssize_t empty_dir_listxattr(struct dentry *dentry, char *list, size_t size) |
1313 | { | |
1314 | return -EOPNOTSUPP; | |
1315 | } | |
1316 | ||
1317 | static const struct inode_operations empty_dir_inode_operations = { | |
1318 | .lookup = empty_dir_lookup, | |
1319 | .permission = generic_permission, | |
1320 | .setattr = empty_dir_setattr, | |
1321 | .getattr = empty_dir_getattr, | |
fbabfd0f EB |
1322 | .listxattr = empty_dir_listxattr, |
1323 | }; | |
1324 | ||
1325 | static loff_t empty_dir_llseek(struct file *file, loff_t offset, int whence) | |
1326 | { | |
1327 | /* An empty directory has two entries . and .. at offsets 0 and 1 */ | |
1328 | return generic_file_llseek_size(file, offset, whence, 2, 2); | |
1329 | } | |
1330 | ||
1331 | static int empty_dir_readdir(struct file *file, struct dir_context *ctx) | |
1332 | { | |
1333 | dir_emit_dots(file, ctx); | |
1334 | return 0; | |
1335 | } | |
1336 | ||
1337 | static const struct file_operations empty_dir_operations = { | |
1338 | .llseek = empty_dir_llseek, | |
1339 | .read = generic_read_dir, | |
c51da20c | 1340 | .iterate_shared = empty_dir_readdir, |
fbabfd0f EB |
1341 | .fsync = noop_fsync, |
1342 | }; | |
1343 | ||
1344 | ||
1345 | void make_empty_dir_inode(struct inode *inode) | |
1346 | { | |
1347 | set_nlink(inode, 2); | |
1348 | inode->i_mode = S_IFDIR | S_IRUGO | S_IXUGO; | |
1349 | inode->i_uid = GLOBAL_ROOT_UID; | |
1350 | inode->i_gid = GLOBAL_ROOT_GID; | |
1351 | inode->i_rdev = 0; | |
4b75de86 | 1352 | inode->i_size = 0; |
fbabfd0f EB |
1353 | inode->i_blkbits = PAGE_SHIFT; |
1354 | inode->i_blocks = 0; | |
1355 | ||
1356 | inode->i_op = &empty_dir_inode_operations; | |
f5c24438 | 1357 | inode->i_opflags &= ~IOP_XATTR; |
fbabfd0f EB |
1358 | inode->i_fop = &empty_dir_operations; |
1359 | } | |
1360 | ||
1361 | bool is_empty_dir_inode(struct inode *inode) | |
1362 | { | |
1363 | return (inode->i_fop == &empty_dir_operations) && | |
1364 | (inode->i_op == &empty_dir_inode_operations); | |
1365 | } |