Commit | Line | Data |
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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> |
5ca14835 | 18 | #include <linux/iversion.h> |
d5aacad5 | 19 | #include <linux/writeback.h> |
ff01bb48 | 20 | #include <linux/buffer_head.h> /* sync_mapping_buffers */ |
31d6d5ce DH |
21 | #include <linux/fs_context.h> |
22 | #include <linux/pseudo_fs.h> | |
a3d1e7eb | 23 | #include <linux/fsnotify.h> |
c843843e DR |
24 | #include <linux/unicode.h> |
25 | #include <linux/fscrypt.h> | |
7cf34c76 | 26 | |
7c0f6ba6 | 27 | #include <linux/uaccess.h> |
1da177e4 | 28 | |
a4464dbc AV |
29 | #include "internal.h" |
30 | ||
b74d24f7 | 31 | int simple_getattr(struct mnt_idmap *idmap, const struct path *path, |
549c7297 CB |
32 | struct kstat *stat, u32 request_mask, |
33 | unsigned int query_flags) | |
1da177e4 | 34 | { |
a528d35e | 35 | struct inode *inode = d_inode(path->dentry); |
b74d24f7 | 36 | generic_fillattr(&nop_mnt_idmap, inode, stat); |
09cbfeaf | 37 | stat->blocks = inode->i_mapping->nrpages << (PAGE_SHIFT - 9); |
1da177e4 LT |
38 | return 0; |
39 | } | |
12f38872 | 40 | EXPORT_SYMBOL(simple_getattr); |
1da177e4 | 41 | |
726c3342 | 42 | int simple_statfs(struct dentry *dentry, struct kstatfs *buf) |
1da177e4 | 43 | { |
726c3342 | 44 | buf->f_type = dentry->d_sb->s_magic; |
09cbfeaf | 45 | buf->f_bsize = PAGE_SIZE; |
1da177e4 LT |
46 | buf->f_namelen = NAME_MAX; |
47 | return 0; | |
48 | } | |
12f38872 | 49 | EXPORT_SYMBOL(simple_statfs); |
1da177e4 LT |
50 | |
51 | /* | |
52 | * Retaining negative dentries for an in-memory filesystem just wastes | |
53 | * memory and lookup time: arrange for them to be deleted immediately. | |
54 | */ | |
b26d4cd3 | 55 | int always_delete_dentry(const struct dentry *dentry) |
1da177e4 LT |
56 | { |
57 | return 1; | |
58 | } | |
b26d4cd3 AV |
59 | EXPORT_SYMBOL(always_delete_dentry); |
60 | ||
61 | const struct dentry_operations simple_dentry_operations = { | |
62 | .d_delete = always_delete_dentry, | |
63 | }; | |
64 | EXPORT_SYMBOL(simple_dentry_operations); | |
1da177e4 LT |
65 | |
66 | /* | |
67 | * Lookup the data. This is trivial - if the dentry didn't already | |
68 | * exist, we know it is negative. Set d_op to delete negative dentries. | |
69 | */ | |
00cd8dd3 | 70 | struct dentry *simple_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags) |
1da177e4 | 71 | { |
1da177e4 LT |
72 | if (dentry->d_name.len > NAME_MAX) |
73 | return ERR_PTR(-ENAMETOOLONG); | |
74931da7 AV |
74 | if (!dentry->d_sb->s_d_op) |
75 | d_set_d_op(dentry, &simple_dentry_operations); | |
1da177e4 LT |
76 | d_add(dentry, NULL); |
77 | return NULL; | |
78 | } | |
12f38872 | 79 | EXPORT_SYMBOL(simple_lookup); |
1da177e4 | 80 | |
1da177e4 LT |
81 | int dcache_dir_open(struct inode *inode, struct file *file) |
82 | { | |
ba65dc5e | 83 | file->private_data = d_alloc_cursor(file->f_path.dentry); |
1da177e4 LT |
84 | |
85 | return file->private_data ? 0 : -ENOMEM; | |
86 | } | |
12f38872 | 87 | EXPORT_SYMBOL(dcache_dir_open); |
1da177e4 LT |
88 | |
89 | int dcache_dir_close(struct inode *inode, struct file *file) | |
90 | { | |
91 | dput(file->private_data); | |
92 | return 0; | |
93 | } | |
12f38872 | 94 | EXPORT_SYMBOL(dcache_dir_close); |
1da177e4 | 95 | |
4f42c1b5 | 96 | /* parent is locked at least shared */ |
d4f4de5e AV |
97 | /* |
98 | * Returns an element of siblings' list. | |
99 | * We are looking for <count>th positive after <p>; if | |
26b6c984 AV |
100 | * found, dentry is grabbed and returned to caller. |
101 | * If no such element exists, NULL is returned. | |
d4f4de5e | 102 | */ |
26b6c984 | 103 | static struct dentry *scan_positives(struct dentry *cursor, |
d4f4de5e AV |
104 | struct list_head *p, |
105 | loff_t count, | |
26b6c984 | 106 | struct dentry *last) |
4f42c1b5 | 107 | { |
d4f4de5e AV |
108 | struct dentry *dentry = cursor->d_parent, *found = NULL; |
109 | ||
110 | spin_lock(&dentry->d_lock); | |
111 | while ((p = p->next) != &dentry->d_subdirs) { | |
4f42c1b5 | 112 | struct dentry *d = list_entry(p, struct dentry, d_child); |
d4f4de5e AV |
113 | // we must at least skip cursors, to avoid livelocks |
114 | if (d->d_flags & DCACHE_DENTRY_CURSOR) | |
115 | continue; | |
116 | if (simple_positive(d) && !--count) { | |
117 | spin_lock_nested(&d->d_lock, DENTRY_D_LOCK_NESTED); | |
118 | if (simple_positive(d)) | |
119 | found = dget_dlock(d); | |
120 | spin_unlock(&d->d_lock); | |
121 | if (likely(found)) | |
122 | break; | |
123 | count = 1; | |
124 | } | |
125 | if (need_resched()) { | |
126 | list_move(&cursor->d_child, p); | |
127 | p = &cursor->d_child; | |
128 | spin_unlock(&dentry->d_lock); | |
129 | cond_resched(); | |
130 | spin_lock(&dentry->d_lock); | |
4f42c1b5 AV |
131 | } |
132 | } | |
d4f4de5e | 133 | spin_unlock(&dentry->d_lock); |
26b6c984 AV |
134 | dput(last); |
135 | return found; | |
4f42c1b5 AV |
136 | } |
137 | ||
965c8e59 | 138 | loff_t dcache_dir_lseek(struct file *file, loff_t offset, int whence) |
1da177e4 | 139 | { |
2fd6b7f5 | 140 | struct dentry *dentry = file->f_path.dentry; |
965c8e59 | 141 | switch (whence) { |
1da177e4 LT |
142 | case 1: |
143 | offset += file->f_pos; | |
df561f66 | 144 | fallthrough; |
1da177e4 LT |
145 | case 0: |
146 | if (offset >= 0) | |
147 | break; | |
df561f66 | 148 | fallthrough; |
1da177e4 | 149 | default: |
1da177e4 LT |
150 | return -EINVAL; |
151 | } | |
152 | if (offset != file->f_pos) { | |
d4f4de5e AV |
153 | struct dentry *cursor = file->private_data; |
154 | struct dentry *to = NULL; | |
d4f4de5e | 155 | |
d4f4de5e AV |
156 | inode_lock_shared(dentry->d_inode); |
157 | ||
26b6c984 AV |
158 | if (offset > 2) |
159 | to = scan_positives(cursor, &dentry->d_subdirs, | |
160 | offset - 2, NULL); | |
161 | spin_lock(&dentry->d_lock); | |
162 | if (to) | |
163 | list_move(&cursor->d_child, &to->d_child); | |
164 | else | |
d4f4de5e | 165 | list_del_init(&cursor->d_child); |
26b6c984 | 166 | spin_unlock(&dentry->d_lock); |
d4f4de5e AV |
167 | dput(to); |
168 | ||
26b6c984 AV |
169 | file->f_pos = offset; |
170 | ||
d4f4de5e | 171 | inode_unlock_shared(dentry->d_inode); |
1da177e4 | 172 | } |
1da177e4 LT |
173 | return offset; |
174 | } | |
12f38872 | 175 | EXPORT_SYMBOL(dcache_dir_lseek); |
1da177e4 | 176 | |
1da177e4 LT |
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; | |
d4f4de5e AV |
187 | struct list_head *anchor = &dentry->d_subdirs; |
188 | struct dentry *next = NULL; | |
189 | struct list_head *p; | |
1da177e4 | 190 | |
5f99f4e7 AV |
191 | if (!dir_emit_dots(file, ctx)) |
192 | return 0; | |
5f99f4e7 | 193 | |
4f42c1b5 | 194 | if (ctx->pos == 2) |
d4f4de5e | 195 | p = anchor; |
26b6c984 | 196 | else if (!list_empty(&cursor->d_child)) |
d4f4de5e | 197 | p = &cursor->d_child; |
26b6c984 AV |
198 | else |
199 | return 0; | |
d4f4de5e | 200 | |
26b6c984 | 201 | while ((next = scan_positives(cursor, p, 1, next)) != NULL) { |
5f99f4e7 | 202 | if (!dir_emit(ctx, next->d_name.name, next->d_name.len, |
364595a6 JL |
203 | d_inode(next)->i_ino, |
204 | fs_umode_to_dtype(d_inode(next)->i_mode))) | |
4f42c1b5 | 205 | break; |
5f99f4e7 | 206 | ctx->pos++; |
26b6c984 | 207 | p = &next->d_child; |
1da177e4 | 208 | } |
d4f4de5e | 209 | spin_lock(&dentry->d_lock); |
26b6c984 AV |
210 | if (next) |
211 | list_move_tail(&cursor->d_child, &next->d_child); | |
212 | else | |
213 | list_del_init(&cursor->d_child); | |
d4f4de5e AV |
214 | spin_unlock(&dentry->d_lock); |
215 | dput(next); | |
216 | ||
1da177e4 LT |
217 | return 0; |
218 | } | |
12f38872 | 219 | EXPORT_SYMBOL(dcache_readdir); |
1da177e4 LT |
220 | |
221 | ssize_t generic_read_dir(struct file *filp, char __user *buf, size_t siz, loff_t *ppos) | |
222 | { | |
223 | return -EISDIR; | |
224 | } | |
12f38872 | 225 | EXPORT_SYMBOL(generic_read_dir); |
1da177e4 | 226 | |
4b6f5d20 | 227 | const struct file_operations simple_dir_operations = { |
1da177e4 LT |
228 | .open = dcache_dir_open, |
229 | .release = dcache_dir_close, | |
230 | .llseek = dcache_dir_lseek, | |
231 | .read = generic_read_dir, | |
4e82901c | 232 | .iterate_shared = dcache_readdir, |
1b061d92 | 233 | .fsync = noop_fsync, |
1da177e4 | 234 | }; |
12f38872 | 235 | EXPORT_SYMBOL(simple_dir_operations); |
1da177e4 | 236 | |
92e1d5be | 237 | const struct inode_operations simple_dir_inode_operations = { |
1da177e4 LT |
238 | .lookup = simple_lookup, |
239 | }; | |
12f38872 | 240 | EXPORT_SYMBOL(simple_dir_inode_operations); |
1da177e4 | 241 | |
a3d1e7eb AV |
242 | static struct dentry *find_next_child(struct dentry *parent, struct dentry *prev) |
243 | { | |
244 | struct dentry *child = NULL; | |
245 | struct list_head *p = prev ? &prev->d_child : &parent->d_subdirs; | |
246 | ||
247 | spin_lock(&parent->d_lock); | |
248 | while ((p = p->next) != &parent->d_subdirs) { | |
249 | struct dentry *d = container_of(p, struct dentry, d_child); | |
250 | if (simple_positive(d)) { | |
251 | spin_lock_nested(&d->d_lock, DENTRY_D_LOCK_NESTED); | |
252 | if (simple_positive(d)) | |
253 | child = dget_dlock(d); | |
254 | spin_unlock(&d->d_lock); | |
255 | if (likely(child)) | |
256 | break; | |
257 | } | |
258 | } | |
259 | spin_unlock(&parent->d_lock); | |
260 | dput(prev); | |
261 | return child; | |
262 | } | |
263 | ||
264 | void simple_recursive_removal(struct dentry *dentry, | |
265 | void (*callback)(struct dentry *)) | |
266 | { | |
267 | struct dentry *this = dget(dentry); | |
268 | while (true) { | |
269 | struct dentry *victim = NULL, *child; | |
270 | struct inode *inode = this->d_inode; | |
271 | ||
272 | inode_lock(inode); | |
273 | if (d_is_dir(this)) | |
274 | inode->i_flags |= S_DEAD; | |
275 | while ((child = find_next_child(this, victim)) == NULL) { | |
276 | // kill and ascend | |
277 | // update metadata while it's still locked | |
f7f43858 | 278 | inode_set_ctime_current(inode); |
a3d1e7eb AV |
279 | clear_nlink(inode); |
280 | inode_unlock(inode); | |
281 | victim = this; | |
282 | this = this->d_parent; | |
283 | inode = this->d_inode; | |
284 | inode_lock(inode); | |
285 | if (simple_positive(victim)) { | |
286 | d_invalidate(victim); // avoid lost mounts | |
287 | if (d_is_dir(victim)) | |
288 | fsnotify_rmdir(inode, victim); | |
289 | else | |
290 | fsnotify_unlink(inode, victim); | |
291 | if (callback) | |
292 | callback(victim); | |
293 | dput(victim); // unpin it | |
294 | } | |
295 | if (victim == dentry) { | |
f7f43858 | 296 | inode->i_mtime = inode_set_ctime_current(inode); |
a3d1e7eb AV |
297 | if (d_is_dir(dentry)) |
298 | drop_nlink(inode); | |
299 | inode_unlock(inode); | |
300 | dput(dentry); | |
301 | return; | |
302 | } | |
303 | } | |
304 | inode_unlock(inode); | |
305 | this = child; | |
306 | } | |
307 | } | |
308 | EXPORT_SYMBOL(simple_recursive_removal); | |
309 | ||
759b9775 HD |
310 | static const struct super_operations simple_super_operations = { |
311 | .statfs = simple_statfs, | |
312 | }; | |
313 | ||
db2c246a | 314 | static int pseudo_fs_fill_super(struct super_block *s, struct fs_context *fc) |
1da177e4 | 315 | { |
31d6d5ce | 316 | struct pseudo_fs_context *ctx = fc->fs_private; |
1da177e4 | 317 | struct inode *root; |
1da177e4 | 318 | |
89a4eb4b | 319 | s->s_maxbytes = MAX_LFS_FILESIZE; |
3971e1a9 AN |
320 | s->s_blocksize = PAGE_SIZE; |
321 | s->s_blocksize_bits = PAGE_SHIFT; | |
8d9e46d8 AV |
322 | s->s_magic = ctx->magic; |
323 | s->s_op = ctx->ops ?: &simple_super_operations; | |
324 | s->s_xattr = ctx->xattr; | |
1da177e4 LT |
325 | s->s_time_gran = 1; |
326 | root = new_inode(s); | |
327 | if (!root) | |
db2c246a DH |
328 | return -ENOMEM; |
329 | ||
1a1c9bb4 JL |
330 | /* |
331 | * since this is the first inode, make it number 1. New inodes created | |
332 | * after this must take care not to collide with it (by passing | |
333 | * max_reserved of 1 to iunique). | |
334 | */ | |
335 | root->i_ino = 1; | |
1da177e4 | 336 | root->i_mode = S_IFDIR | S_IRUSR | S_IWUSR; |
f7f43858 | 337 | root->i_atime = root->i_mtime = inode_set_ctime_current(root); |
8d9e46d8 AV |
338 | s->s_root = d_make_root(root); |
339 | if (!s->s_root) | |
db2c246a | 340 | return -ENOMEM; |
8d9e46d8 | 341 | s->s_d_op = ctx->dops; |
31d6d5ce | 342 | return 0; |
db2c246a | 343 | } |
8d9e46d8 | 344 | |
db2c246a DH |
345 | static int pseudo_fs_get_tree(struct fs_context *fc) |
346 | { | |
2ac295d4 | 347 | return get_tree_nodev(fc, pseudo_fs_fill_super); |
31d6d5ce DH |
348 | } |
349 | ||
350 | static void pseudo_fs_free(struct fs_context *fc) | |
351 | { | |
352 | kfree(fc->fs_private); | |
353 | } | |
354 | ||
355 | static const struct fs_context_operations pseudo_fs_context_ops = { | |
356 | .free = pseudo_fs_free, | |
357 | .get_tree = pseudo_fs_get_tree, | |
358 | }; | |
359 | ||
360 | /* | |
361 | * Common helper for pseudo-filesystems (sockfs, pipefs, bdev - stuff that | |
362 | * will never be mountable) | |
363 | */ | |
364 | struct pseudo_fs_context *init_pseudo(struct fs_context *fc, | |
365 | unsigned long magic) | |
366 | { | |
367 | struct pseudo_fs_context *ctx; | |
368 | ||
369 | ctx = kzalloc(sizeof(struct pseudo_fs_context), GFP_KERNEL); | |
370 | if (likely(ctx)) { | |
371 | ctx->magic = magic; | |
372 | fc->fs_private = ctx; | |
373 | fc->ops = &pseudo_fs_context_ops; | |
db2c246a DH |
374 | fc->sb_flags |= SB_NOUSER; |
375 | fc->global = true; | |
1da177e4 | 376 | } |
31d6d5ce | 377 | return ctx; |
1da177e4 | 378 | } |
31d6d5ce | 379 | EXPORT_SYMBOL(init_pseudo); |
1da177e4 | 380 | |
20955e89 SB |
381 | int simple_open(struct inode *inode, struct file *file) |
382 | { | |
383 | if (inode->i_private) | |
384 | file->private_data = inode->i_private; | |
385 | return 0; | |
386 | } | |
12f38872 | 387 | EXPORT_SYMBOL(simple_open); |
20955e89 | 388 | |
1da177e4 LT |
389 | int simple_link(struct dentry *old_dentry, struct inode *dir, struct dentry *dentry) |
390 | { | |
dea655c2 | 391 | struct inode *inode = d_inode(old_dentry); |
1da177e4 | 392 | |
f7f43858 JL |
393 | dir->i_mtime = inode_set_ctime_to_ts(dir, |
394 | inode_set_ctime_current(inode)); | |
d8c76e6f | 395 | inc_nlink(inode); |
7de9c6ee | 396 | ihold(inode); |
1da177e4 LT |
397 | dget(dentry); |
398 | d_instantiate(dentry, inode); | |
399 | return 0; | |
400 | } | |
12f38872 | 401 | EXPORT_SYMBOL(simple_link); |
1da177e4 | 402 | |
1da177e4 LT |
403 | int simple_empty(struct dentry *dentry) |
404 | { | |
405 | struct dentry *child; | |
406 | int ret = 0; | |
407 | ||
2fd6b7f5 | 408 | spin_lock(&dentry->d_lock); |
946e51f2 | 409 | list_for_each_entry(child, &dentry->d_subdirs, d_child) { |
da502956 NP |
410 | spin_lock_nested(&child->d_lock, DENTRY_D_LOCK_NESTED); |
411 | if (simple_positive(child)) { | |
412 | spin_unlock(&child->d_lock); | |
1da177e4 | 413 | goto out; |
da502956 NP |
414 | } |
415 | spin_unlock(&child->d_lock); | |
416 | } | |
1da177e4 LT |
417 | ret = 1; |
418 | out: | |
2fd6b7f5 | 419 | spin_unlock(&dentry->d_lock); |
1da177e4 LT |
420 | return ret; |
421 | } | |
12f38872 | 422 | EXPORT_SYMBOL(simple_empty); |
1da177e4 LT |
423 | |
424 | int simple_unlink(struct inode *dir, struct dentry *dentry) | |
425 | { | |
dea655c2 | 426 | struct inode *inode = d_inode(dentry); |
1da177e4 | 427 | |
f7f43858 JL |
428 | dir->i_mtime = inode_set_ctime_to_ts(dir, |
429 | inode_set_ctime_current(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 | 447 | |
0c476792 JL |
448 | /** |
449 | * simple_rename_timestamp - update the various inode timestamps for rename | |
450 | * @old_dir: old parent directory | |
451 | * @old_dentry: dentry that is being renamed | |
452 | * @new_dir: new parent directory | |
453 | * @new_dentry: target for rename | |
454 | * | |
455 | * POSIX mandates that the old and new parent directories have their ctime and | |
456 | * mtime updated, and that inodes of @old_dentry and @new_dentry (if any), have | |
457 | * their ctime updated. | |
458 | */ | |
459 | void simple_rename_timestamp(struct inode *old_dir, struct dentry *old_dentry, | |
460 | struct inode *new_dir, struct dentry *new_dentry) | |
461 | { | |
462 | struct inode *newino = d_inode(new_dentry); | |
463 | ||
464 | old_dir->i_mtime = inode_set_ctime_current(old_dir); | |
465 | if (new_dir != old_dir) | |
466 | new_dir->i_mtime = inode_set_ctime_current(new_dir); | |
467 | inode_set_ctime_current(d_inode(old_dentry)); | |
468 | if (newino) | |
469 | inode_set_ctime_current(newino); | |
470 | } | |
471 | EXPORT_SYMBOL_GPL(simple_rename_timestamp); | |
472 | ||
6429e463 LB |
473 | int simple_rename_exchange(struct inode *old_dir, struct dentry *old_dentry, |
474 | struct inode *new_dir, struct dentry *new_dentry) | |
475 | { | |
476 | bool old_is_dir = d_is_dir(old_dentry); | |
477 | bool new_is_dir = d_is_dir(new_dentry); | |
478 | ||
479 | if (old_dir != new_dir && old_is_dir != new_is_dir) { | |
480 | if (old_is_dir) { | |
481 | drop_nlink(old_dir); | |
482 | inc_nlink(new_dir); | |
483 | } else { | |
484 | drop_nlink(new_dir); | |
485 | inc_nlink(old_dir); | |
486 | } | |
487 | } | |
0c476792 | 488 | simple_rename_timestamp(old_dir, old_dentry, new_dir, new_dentry); |
6429e463 LB |
489 | return 0; |
490 | } | |
491 | EXPORT_SYMBOL_GPL(simple_rename_exchange); | |
492 | ||
e18275ae | 493 | int simple_rename(struct mnt_idmap *idmap, struct inode *old_dir, |
549c7297 CB |
494 | struct dentry *old_dentry, struct inode *new_dir, |
495 | struct dentry *new_dentry, unsigned int flags) | |
1da177e4 | 496 | { |
e36cb0b8 | 497 | int they_are_dirs = d_is_dir(old_dentry); |
1da177e4 | 498 | |
3871cb8c | 499 | if (flags & ~(RENAME_NOREPLACE | RENAME_EXCHANGE)) |
e0e0be8a MS |
500 | return -EINVAL; |
501 | ||
3871cb8c LB |
502 | if (flags & RENAME_EXCHANGE) |
503 | return simple_rename_exchange(old_dir, old_dentry, new_dir, new_dentry); | |
504 | ||
1da177e4 LT |
505 | if (!simple_empty(new_dentry)) |
506 | return -ENOTEMPTY; | |
507 | ||
dea655c2 | 508 | if (d_really_is_positive(new_dentry)) { |
1da177e4 | 509 | simple_unlink(new_dir, new_dentry); |
841590ce | 510 | if (they_are_dirs) { |
dea655c2 | 511 | drop_nlink(d_inode(new_dentry)); |
9a53c3a7 | 512 | drop_nlink(old_dir); |
841590ce | 513 | } |
1da177e4 | 514 | } else if (they_are_dirs) { |
9a53c3a7 | 515 | drop_nlink(old_dir); |
d8c76e6f | 516 | inc_nlink(new_dir); |
1da177e4 LT |
517 | } |
518 | ||
0c476792 | 519 | simple_rename_timestamp(old_dir, old_dentry, new_dir, new_dentry); |
1da177e4 LT |
520 | return 0; |
521 | } | |
12f38872 | 522 | EXPORT_SYMBOL(simple_rename); |
1da177e4 | 523 | |
7bb46a67 | 524 | /** |
eef2380c | 525 | * simple_setattr - setattr for simple filesystem |
c1632a0f | 526 | * @idmap: idmap of the target mount |
7bb46a67 | 527 | * @dentry: dentry |
528 | * @iattr: iattr structure | |
529 | * | |
530 | * Returns 0 on success, -error on failure. | |
531 | * | |
eef2380c CH |
532 | * simple_setattr is a simple ->setattr implementation without a proper |
533 | * implementation of size changes. | |
534 | * | |
535 | * It can either be used for in-memory filesystems or special files | |
536 | * on simple regular filesystems. Anything that needs to change on-disk | |
537 | * or wire state on size changes needs its own setattr method. | |
7bb46a67 | 538 | */ |
c1632a0f | 539 | int simple_setattr(struct mnt_idmap *idmap, struct dentry *dentry, |
549c7297 | 540 | struct iattr *iattr) |
7bb46a67 | 541 | { |
dea655c2 | 542 | struct inode *inode = d_inode(dentry); |
7bb46a67 | 543 | int error; |
544 | ||
c1632a0f | 545 | error = setattr_prepare(idmap, dentry, iattr); |
7bb46a67 | 546 | if (error) |
547 | return error; | |
548 | ||
2c27c65e CH |
549 | if (iattr->ia_valid & ATTR_SIZE) |
550 | truncate_setsize(inode, iattr->ia_size); | |
c1632a0f | 551 | setattr_copy(idmap, inode, iattr); |
eef2380c CH |
552 | mark_inode_dirty(inode); |
553 | return 0; | |
7bb46a67 | 554 | } |
555 | EXPORT_SYMBOL(simple_setattr); | |
556 | ||
a77f580a | 557 | static int simple_read_folio(struct file *file, struct folio *folio) |
1da177e4 | 558 | { |
a77f580a MWO |
559 | folio_zero_range(folio, 0, folio_size(folio)); |
560 | flush_dcache_folio(folio); | |
561 | folio_mark_uptodate(folio); | |
562 | folio_unlock(folio); | |
1da177e4 LT |
563 | return 0; |
564 | } | |
565 | ||
afddba49 | 566 | int simple_write_begin(struct file *file, struct address_space *mapping, |
9d6b0cd7 | 567 | loff_t pos, unsigned len, |
afddba49 NP |
568 | struct page **pagep, void **fsdata) |
569 | { | |
570 | struct page *page; | |
571 | pgoff_t index; | |
afddba49 | 572 | |
09cbfeaf | 573 | index = pos >> PAGE_SHIFT; |
afddba49 | 574 | |
b7446e7c | 575 | page = grab_cache_page_write_begin(mapping, index); |
afddba49 NP |
576 | if (!page) |
577 | return -ENOMEM; | |
578 | ||
579 | *pagep = page; | |
580 | ||
09cbfeaf KS |
581 | if (!PageUptodate(page) && (len != PAGE_SIZE)) { |
582 | unsigned from = pos & (PAGE_SIZE - 1); | |
193cf4b9 | 583 | |
09cbfeaf | 584 | zero_user_segments(page, 0, from, from + len, PAGE_SIZE); |
193cf4b9 BH |
585 | } |
586 | return 0; | |
afddba49 | 587 | } |
12f38872 | 588 | EXPORT_SYMBOL(simple_write_begin); |
afddba49 | 589 | |
ad2a722f BH |
590 | /** |
591 | * simple_write_end - .write_end helper for non-block-device FSes | |
8e88bfba | 592 | * @file: See .write_end of address_space_operations |
ad2a722f BH |
593 | * @mapping: " |
594 | * @pos: " | |
595 | * @len: " | |
596 | * @copied: " | |
597 | * @page: " | |
598 | * @fsdata: " | |
599 | * | |
600 | * simple_write_end does the minimum needed for updating a page after writing is | |
601 | * done. It has the same API signature as the .write_end of | |
602 | * address_space_operations vector. So it can just be set onto .write_end for | |
603 | * FSes that don't need any other processing. i_mutex is assumed to be held. | |
604 | * Block based filesystems should use generic_write_end(). | |
605 | * NOTE: Even though i_size might get updated by this function, mark_inode_dirty | |
606 | * is not called, so a filesystem that actually does store data in .write_inode | |
607 | * should extend on what's done here with a call to mark_inode_dirty() in the | |
608 | * case that i_size has changed. | |
04fff641 | 609 | * |
a77f580a | 610 | * Use *ONLY* with simple_read_folio() |
ad2a722f | 611 | */ |
c1e3dbe9 | 612 | static int simple_write_end(struct file *file, struct address_space *mapping, |
afddba49 NP |
613 | loff_t pos, unsigned len, unsigned copied, |
614 | struct page *page, void *fsdata) | |
615 | { | |
ad2a722f BH |
616 | struct inode *inode = page->mapping->host; |
617 | loff_t last_pos = pos + copied; | |
afddba49 NP |
618 | |
619 | /* zero the stale part of the page if we did a short copy */ | |
04fff641 AV |
620 | if (!PageUptodate(page)) { |
621 | if (copied < len) { | |
622 | unsigned from = pos & (PAGE_SIZE - 1); | |
afddba49 | 623 | |
04fff641 AV |
624 | zero_user(page, from + copied, len - copied); |
625 | } | |
ad2a722f | 626 | SetPageUptodate(page); |
04fff641 | 627 | } |
ad2a722f BH |
628 | /* |
629 | * No need to use i_size_read() here, the i_size | |
630 | * cannot change under us because we hold the i_mutex. | |
631 | */ | |
632 | if (last_pos > inode->i_size) | |
633 | i_size_write(inode, last_pos); | |
afddba49 | 634 | |
ad2a722f | 635 | set_page_dirty(page); |
afddba49 | 636 | unlock_page(page); |
09cbfeaf | 637 | put_page(page); |
afddba49 NP |
638 | |
639 | return copied; | |
640 | } | |
c1e3dbe9 CH |
641 | |
642 | /* | |
643 | * Provides ramfs-style behavior: data in the pagecache, but no writeback. | |
644 | */ | |
645 | const struct address_space_operations ram_aops = { | |
a77f580a | 646 | .read_folio = simple_read_folio, |
c1e3dbe9 CH |
647 | .write_begin = simple_write_begin, |
648 | .write_end = simple_write_end, | |
46de8b97 | 649 | .dirty_folio = noop_dirty_folio, |
c1e3dbe9 CH |
650 | }; |
651 | EXPORT_SYMBOL(ram_aops); | |
afddba49 | 652 | |
1a1c9bb4 JL |
653 | /* |
654 | * the inodes created here are not hashed. If you use iunique to generate | |
655 | * unique inode values later for this filesystem, then you must take care | |
656 | * to pass it an appropriate max_reserved value to avoid collisions. | |
657 | */ | |
7d683a09 | 658 | int simple_fill_super(struct super_block *s, unsigned long magic, |
cda37124 | 659 | const struct tree_descr *files) |
1da177e4 | 660 | { |
1da177e4 LT |
661 | struct inode *inode; |
662 | struct dentry *root; | |
663 | struct dentry *dentry; | |
664 | int i; | |
665 | ||
09cbfeaf KS |
666 | s->s_blocksize = PAGE_SIZE; |
667 | s->s_blocksize_bits = PAGE_SHIFT; | |
1da177e4 | 668 | s->s_magic = magic; |
759b9775 | 669 | s->s_op = &simple_super_operations; |
1da177e4 LT |
670 | s->s_time_gran = 1; |
671 | ||
672 | inode = new_inode(s); | |
673 | if (!inode) | |
674 | return -ENOMEM; | |
1a1c9bb4 JL |
675 | /* |
676 | * because the root inode is 1, the files array must not contain an | |
677 | * entry at index 1 | |
678 | */ | |
679 | inode->i_ino = 1; | |
1da177e4 | 680 | inode->i_mode = S_IFDIR | 0755; |
f7f43858 | 681 | inode->i_atime = inode->i_mtime = inode_set_ctime_current(inode); |
1da177e4 LT |
682 | inode->i_op = &simple_dir_inode_operations; |
683 | inode->i_fop = &simple_dir_operations; | |
bfe86848 | 684 | set_nlink(inode, 2); |
48fde701 AV |
685 | root = d_make_root(inode); |
686 | if (!root) | |
1da177e4 | 687 | return -ENOMEM; |
1da177e4 LT |
688 | for (i = 0; !files->name || files->name[0]; i++, files++) { |
689 | if (!files->name) | |
690 | continue; | |
1a1c9bb4 JL |
691 | |
692 | /* warn if it tries to conflict with the root inode */ | |
693 | if (unlikely(i == 1)) | |
694 | printk(KERN_WARNING "%s: %s passed in a files array" | |
695 | "with an index of 1!\n", __func__, | |
696 | s->s_type->name); | |
697 | ||
1da177e4 LT |
698 | dentry = d_alloc_name(root, files->name); |
699 | if (!dentry) | |
700 | goto out; | |
701 | inode = new_inode(s); | |
32096ea1 KK |
702 | if (!inode) { |
703 | dput(dentry); | |
1da177e4 | 704 | goto out; |
32096ea1 | 705 | } |
1da177e4 | 706 | inode->i_mode = S_IFREG | files->mode; |
f7f43858 | 707 | inode->i_atime = inode->i_mtime = inode_set_ctime_current(inode); |
1da177e4 LT |
708 | inode->i_fop = files->ops; |
709 | inode->i_ino = i; | |
710 | d_add(dentry, inode); | |
711 | } | |
712 | s->s_root = root; | |
713 | return 0; | |
714 | out: | |
715 | d_genocide(root); | |
640946f2 | 716 | shrink_dcache_parent(root); |
1da177e4 LT |
717 | dput(root); |
718 | return -ENOMEM; | |
719 | } | |
12f38872 | 720 | EXPORT_SYMBOL(simple_fill_super); |
1da177e4 LT |
721 | |
722 | static DEFINE_SPINLOCK(pin_fs_lock); | |
723 | ||
1f5ce9e9 | 724 | int simple_pin_fs(struct file_system_type *type, struct vfsmount **mount, int *count) |
1da177e4 LT |
725 | { |
726 | struct vfsmount *mnt = NULL; | |
727 | spin_lock(&pin_fs_lock); | |
728 | if (unlikely(!*mount)) { | |
729 | spin_unlock(&pin_fs_lock); | |
1751e8a6 | 730 | mnt = vfs_kern_mount(type, SB_KERNMOUNT, type->name, NULL); |
1da177e4 LT |
731 | if (IS_ERR(mnt)) |
732 | return PTR_ERR(mnt); | |
733 | spin_lock(&pin_fs_lock); | |
734 | if (!*mount) | |
735 | *mount = mnt; | |
736 | } | |
737 | mntget(*mount); | |
738 | ++*count; | |
739 | spin_unlock(&pin_fs_lock); | |
740 | mntput(mnt); | |
741 | return 0; | |
742 | } | |
12f38872 | 743 | EXPORT_SYMBOL(simple_pin_fs); |
1da177e4 LT |
744 | |
745 | void simple_release_fs(struct vfsmount **mount, int *count) | |
746 | { | |
747 | struct vfsmount *mnt; | |
748 | spin_lock(&pin_fs_lock); | |
749 | mnt = *mount; | |
750 | if (!--*count) | |
751 | *mount = NULL; | |
752 | spin_unlock(&pin_fs_lock); | |
753 | mntput(mnt); | |
754 | } | |
12f38872 | 755 | EXPORT_SYMBOL(simple_release_fs); |
1da177e4 | 756 | |
6d1029b5 AM |
757 | /** |
758 | * simple_read_from_buffer - copy data from the buffer to user space | |
759 | * @to: the user space buffer to read to | |
760 | * @count: the maximum number of bytes to read | |
761 | * @ppos: the current position in the buffer | |
762 | * @from: the buffer to read from | |
763 | * @available: the size of the buffer | |
764 | * | |
765 | * The simple_read_from_buffer() function reads up to @count bytes from the | |
766 | * buffer @from at offset @ppos into the user space address starting at @to. | |
767 | * | |
768 | * On success, the number of bytes read is returned and the offset @ppos is | |
769 | * advanced by this number, or negative value is returned on error. | |
770 | **/ | |
1da177e4 LT |
771 | ssize_t simple_read_from_buffer(void __user *to, size_t count, loff_t *ppos, |
772 | const void *from, size_t available) | |
773 | { | |
774 | loff_t pos = *ppos; | |
14be2746 SR |
775 | size_t ret; |
776 | ||
1da177e4 LT |
777 | if (pos < 0) |
778 | return -EINVAL; | |
14be2746 | 779 | if (pos >= available || !count) |
1da177e4 LT |
780 | return 0; |
781 | if (count > available - pos) | |
782 | count = available - pos; | |
14be2746 SR |
783 | ret = copy_to_user(to, from + pos, count); |
784 | if (ret == count) | |
1da177e4 | 785 | return -EFAULT; |
14be2746 | 786 | count -= ret; |
1da177e4 LT |
787 | *ppos = pos + count; |
788 | return count; | |
789 | } | |
12f38872 | 790 | EXPORT_SYMBOL(simple_read_from_buffer); |
1da177e4 | 791 | |
6a727b43 JS |
792 | /** |
793 | * simple_write_to_buffer - copy data from user space to the buffer | |
794 | * @to: the buffer to write to | |
795 | * @available: the size of the buffer | |
796 | * @ppos: the current position in the buffer | |
797 | * @from: the user space buffer to read from | |
798 | * @count: the maximum number of bytes to read | |
799 | * | |
800 | * The simple_write_to_buffer() function reads up to @count bytes from the user | |
801 | * space address starting at @from into the buffer @to at offset @ppos. | |
802 | * | |
803 | * On success, the number of bytes written is returned and the offset @ppos is | |
804 | * advanced by this number, or negative value is returned on error. | |
805 | **/ | |
806 | ssize_t simple_write_to_buffer(void *to, size_t available, loff_t *ppos, | |
807 | const void __user *from, size_t count) | |
808 | { | |
809 | loff_t pos = *ppos; | |
810 | size_t res; | |
811 | ||
812 | if (pos < 0) | |
813 | return -EINVAL; | |
814 | if (pos >= available || !count) | |
815 | return 0; | |
816 | if (count > available - pos) | |
817 | count = available - pos; | |
818 | res = copy_from_user(to + pos, from, count); | |
819 | if (res == count) | |
820 | return -EFAULT; | |
821 | count -= res; | |
822 | *ppos = pos + count; | |
823 | return count; | |
824 | } | |
12f38872 | 825 | EXPORT_SYMBOL(simple_write_to_buffer); |
6a727b43 | 826 | |
6d1029b5 AM |
827 | /** |
828 | * memory_read_from_buffer - copy data from the buffer | |
829 | * @to: the kernel space buffer to read to | |
830 | * @count: the maximum number of bytes to read | |
831 | * @ppos: the current position in the buffer | |
832 | * @from: the buffer to read from | |
833 | * @available: the size of the buffer | |
834 | * | |
835 | * The memory_read_from_buffer() function reads up to @count bytes from the | |
836 | * buffer @from at offset @ppos into the kernel space address starting at @to. | |
837 | * | |
838 | * On success, the number of bytes read is returned and the offset @ppos is | |
839 | * advanced by this number, or negative value is returned on error. | |
840 | **/ | |
93b07113 AM |
841 | ssize_t memory_read_from_buffer(void *to, size_t count, loff_t *ppos, |
842 | const void *from, size_t available) | |
843 | { | |
844 | loff_t pos = *ppos; | |
845 | ||
846 | if (pos < 0) | |
847 | return -EINVAL; | |
848 | if (pos >= available) | |
849 | return 0; | |
850 | if (count > available - pos) | |
851 | count = available - pos; | |
852 | memcpy(to, from + pos, count); | |
853 | *ppos = pos + count; | |
854 | ||
855 | return count; | |
856 | } | |
12f38872 | 857 | EXPORT_SYMBOL(memory_read_from_buffer); |
93b07113 | 858 | |
1da177e4 LT |
859 | /* |
860 | * Transaction based IO. | |
861 | * The file expects a single write which triggers the transaction, and then | |
862 | * possibly a read which collects the result - which is stored in a | |
863 | * file-local buffer. | |
864 | */ | |
76791ab2 IM |
865 | |
866 | void simple_transaction_set(struct file *file, size_t n) | |
867 | { | |
868 | struct simple_transaction_argresp *ar = file->private_data; | |
869 | ||
870 | BUG_ON(n > SIMPLE_TRANSACTION_LIMIT); | |
871 | ||
872 | /* | |
873 | * The barrier ensures that ar->size will really remain zero until | |
874 | * ar->data is ready for reading. | |
875 | */ | |
876 | smp_mb(); | |
877 | ar->size = n; | |
878 | } | |
12f38872 | 879 | EXPORT_SYMBOL(simple_transaction_set); |
76791ab2 | 880 | |
1da177e4 LT |
881 | char *simple_transaction_get(struct file *file, const char __user *buf, size_t size) |
882 | { | |
883 | struct simple_transaction_argresp *ar; | |
884 | static DEFINE_SPINLOCK(simple_transaction_lock); | |
885 | ||
886 | if (size > SIMPLE_TRANSACTION_LIMIT - 1) | |
887 | return ERR_PTR(-EFBIG); | |
888 | ||
889 | ar = (struct simple_transaction_argresp *)get_zeroed_page(GFP_KERNEL); | |
890 | if (!ar) | |
891 | return ERR_PTR(-ENOMEM); | |
892 | ||
893 | spin_lock(&simple_transaction_lock); | |
894 | ||
895 | /* only one write allowed per open */ | |
896 | if (file->private_data) { | |
897 | spin_unlock(&simple_transaction_lock); | |
898 | free_page((unsigned long)ar); | |
899 | return ERR_PTR(-EBUSY); | |
900 | } | |
901 | ||
902 | file->private_data = ar; | |
903 | ||
904 | spin_unlock(&simple_transaction_lock); | |
905 | ||
906 | if (copy_from_user(ar->data, buf, size)) | |
907 | return ERR_PTR(-EFAULT); | |
908 | ||
909 | return ar->data; | |
910 | } | |
12f38872 | 911 | EXPORT_SYMBOL(simple_transaction_get); |
1da177e4 LT |
912 | |
913 | ssize_t simple_transaction_read(struct file *file, char __user *buf, size_t size, loff_t *pos) | |
914 | { | |
915 | struct simple_transaction_argresp *ar = file->private_data; | |
916 | ||
917 | if (!ar) | |
918 | return 0; | |
919 | return simple_read_from_buffer(buf, size, pos, ar->data, ar->size); | |
920 | } | |
12f38872 | 921 | EXPORT_SYMBOL(simple_transaction_read); |
1da177e4 LT |
922 | |
923 | int simple_transaction_release(struct inode *inode, struct file *file) | |
924 | { | |
925 | free_page((unsigned long)file->private_data); | |
926 | return 0; | |
927 | } | |
12f38872 | 928 | EXPORT_SYMBOL(simple_transaction_release); |
1da177e4 | 929 | |
acaefc25 AB |
930 | /* Simple attribute files */ |
931 | ||
932 | struct simple_attr { | |
8b88b099 CH |
933 | int (*get)(void *, u64 *); |
934 | int (*set)(void *, u64); | |
acaefc25 AB |
935 | char get_buf[24]; /* enough to store a u64 and "\n\0" */ |
936 | char set_buf[24]; | |
937 | void *data; | |
938 | const char *fmt; /* format for read operation */ | |
7cf34c76 | 939 | struct mutex mutex; /* protects access to these buffers */ |
acaefc25 AB |
940 | }; |
941 | ||
942 | /* simple_attr_open is called by an actual attribute open file operation | |
943 | * to set the attribute specific access operations. */ | |
944 | int simple_attr_open(struct inode *inode, struct file *file, | |
8b88b099 | 945 | int (*get)(void *, u64 *), int (*set)(void *, u64), |
acaefc25 AB |
946 | const char *fmt) |
947 | { | |
948 | struct simple_attr *attr; | |
949 | ||
a65cab7d | 950 | attr = kzalloc(sizeof(*attr), GFP_KERNEL); |
acaefc25 AB |
951 | if (!attr) |
952 | return -ENOMEM; | |
953 | ||
954 | attr->get = get; | |
955 | attr->set = set; | |
8e18e294 | 956 | attr->data = inode->i_private; |
acaefc25 | 957 | attr->fmt = fmt; |
7cf34c76 | 958 | mutex_init(&attr->mutex); |
acaefc25 AB |
959 | |
960 | file->private_data = attr; | |
961 | ||
962 | return nonseekable_open(inode, file); | |
963 | } | |
12f38872 | 964 | EXPORT_SYMBOL_GPL(simple_attr_open); |
acaefc25 | 965 | |
74bedc4d | 966 | int simple_attr_release(struct inode *inode, struct file *file) |
acaefc25 AB |
967 | { |
968 | kfree(file->private_data); | |
969 | return 0; | |
970 | } | |
12f38872 | 971 | EXPORT_SYMBOL_GPL(simple_attr_release); /* GPL-only? This? Really? */ |
acaefc25 AB |
972 | |
973 | /* read from the buffer that is filled with the get function */ | |
974 | ssize_t simple_attr_read(struct file *file, char __user *buf, | |
975 | size_t len, loff_t *ppos) | |
976 | { | |
977 | struct simple_attr *attr; | |
978 | size_t size; | |
979 | ssize_t ret; | |
980 | ||
981 | attr = file->private_data; | |
982 | ||
983 | if (!attr->get) | |
984 | return -EACCES; | |
985 | ||
9261303a CH |
986 | ret = mutex_lock_interruptible(&attr->mutex); |
987 | if (ret) | |
988 | return ret; | |
989 | ||
a65cab7d EB |
990 | if (*ppos && attr->get_buf[0]) { |
991 | /* continued read */ | |
acaefc25 | 992 | size = strlen(attr->get_buf); |
a65cab7d EB |
993 | } else { |
994 | /* first read */ | |
8b88b099 CH |
995 | u64 val; |
996 | ret = attr->get(attr->data, &val); | |
997 | if (ret) | |
998 | goto out; | |
999 | ||
acaefc25 | 1000 | size = scnprintf(attr->get_buf, sizeof(attr->get_buf), |
8b88b099 CH |
1001 | attr->fmt, (unsigned long long)val); |
1002 | } | |
acaefc25 AB |
1003 | |
1004 | ret = simple_read_from_buffer(buf, len, ppos, attr->get_buf, size); | |
8b88b099 | 1005 | out: |
7cf34c76 | 1006 | mutex_unlock(&attr->mutex); |
acaefc25 AB |
1007 | return ret; |
1008 | } | |
12f38872 | 1009 | EXPORT_SYMBOL_GPL(simple_attr_read); |
acaefc25 AB |
1010 | |
1011 | /* interpret the buffer as a number to call the set function with */ | |
2e41f274 AM |
1012 | static ssize_t simple_attr_write_xsigned(struct file *file, const char __user *buf, |
1013 | size_t len, loff_t *ppos, bool is_signed) | |
acaefc25 AB |
1014 | { |
1015 | struct simple_attr *attr; | |
488dac0c | 1016 | unsigned long long val; |
acaefc25 AB |
1017 | size_t size; |
1018 | ssize_t ret; | |
1019 | ||
1020 | attr = file->private_data; | |
acaefc25 AB |
1021 | if (!attr->set) |
1022 | return -EACCES; | |
1023 | ||
9261303a CH |
1024 | ret = mutex_lock_interruptible(&attr->mutex); |
1025 | if (ret) | |
1026 | return ret; | |
1027 | ||
acaefc25 AB |
1028 | ret = -EFAULT; |
1029 | size = min(sizeof(attr->set_buf) - 1, len); | |
1030 | if (copy_from_user(attr->set_buf, buf, size)) | |
1031 | goto out; | |
1032 | ||
acaefc25 | 1033 | attr->set_buf[size] = '\0'; |
2e41f274 AM |
1034 | if (is_signed) |
1035 | ret = kstrtoll(attr->set_buf, 0, &val); | |
1036 | else | |
1037 | ret = kstrtoull(attr->set_buf, 0, &val); | |
488dac0c YY |
1038 | if (ret) |
1039 | goto out; | |
05cc0cee WF |
1040 | ret = attr->set(attr->data, val); |
1041 | if (ret == 0) | |
1042 | ret = len; /* on success, claim we got the whole input */ | |
acaefc25 | 1043 | out: |
7cf34c76 | 1044 | mutex_unlock(&attr->mutex); |
acaefc25 AB |
1045 | return ret; |
1046 | } | |
2e41f274 AM |
1047 | |
1048 | ssize_t simple_attr_write(struct file *file, const char __user *buf, | |
1049 | size_t len, loff_t *ppos) | |
1050 | { | |
1051 | return simple_attr_write_xsigned(file, buf, len, ppos, false); | |
1052 | } | |
12f38872 | 1053 | EXPORT_SYMBOL_GPL(simple_attr_write); |
acaefc25 | 1054 | |
2e41f274 AM |
1055 | ssize_t simple_attr_write_signed(struct file *file, const char __user *buf, |
1056 | size_t len, loff_t *ppos) | |
1057 | { | |
1058 | return simple_attr_write_xsigned(file, buf, len, ppos, true); | |
1059 | } | |
1060 | EXPORT_SYMBOL_GPL(simple_attr_write_signed); | |
1061 | ||
2596110a CH |
1062 | /** |
1063 | * generic_fh_to_dentry - generic helper for the fh_to_dentry export operation | |
1064 | * @sb: filesystem to do the file handle conversion on | |
1065 | * @fid: file handle to convert | |
1066 | * @fh_len: length of the file handle in bytes | |
1067 | * @fh_type: type of file handle | |
1068 | * @get_inode: filesystem callback to retrieve inode | |
1069 | * | |
1070 | * This function decodes @fid as long as it has one of the well-known | |
1071 | * Linux filehandle types and calls @get_inode on it to retrieve the | |
1072 | * inode for the object specified in the file handle. | |
1073 | */ | |
1074 | struct dentry *generic_fh_to_dentry(struct super_block *sb, struct fid *fid, | |
1075 | int fh_len, int fh_type, struct inode *(*get_inode) | |
1076 | (struct super_block *sb, u64 ino, u32 gen)) | |
1077 | { | |
1078 | struct inode *inode = NULL; | |
1079 | ||
1080 | if (fh_len < 2) | |
1081 | return NULL; | |
1082 | ||
1083 | switch (fh_type) { | |
1084 | case FILEID_INO32_GEN: | |
1085 | case FILEID_INO32_GEN_PARENT: | |
1086 | inode = get_inode(sb, fid->i32.ino, fid->i32.gen); | |
1087 | break; | |
1088 | } | |
1089 | ||
4ea3ada2 | 1090 | return d_obtain_alias(inode); |
2596110a CH |
1091 | } |
1092 | EXPORT_SYMBOL_GPL(generic_fh_to_dentry); | |
1093 | ||
1094 | /** | |
ca186830 | 1095 | * generic_fh_to_parent - generic helper for the fh_to_parent export operation |
2596110a CH |
1096 | * @sb: filesystem to do the file handle conversion on |
1097 | * @fid: file handle to convert | |
1098 | * @fh_len: length of the file handle in bytes | |
1099 | * @fh_type: type of file handle | |
1100 | * @get_inode: filesystem callback to retrieve inode | |
1101 | * | |
1102 | * This function decodes @fid as long as it has one of the well-known | |
1103 | * Linux filehandle types and calls @get_inode on it to retrieve the | |
1104 | * inode for the _parent_ object specified in the file handle if it | |
1105 | * is specified in the file handle, or NULL otherwise. | |
1106 | */ | |
1107 | struct dentry *generic_fh_to_parent(struct super_block *sb, struct fid *fid, | |
1108 | int fh_len, int fh_type, struct inode *(*get_inode) | |
1109 | (struct super_block *sb, u64 ino, u32 gen)) | |
1110 | { | |
1111 | struct inode *inode = NULL; | |
1112 | ||
1113 | if (fh_len <= 2) | |
1114 | return NULL; | |
1115 | ||
1116 | switch (fh_type) { | |
1117 | case FILEID_INO32_GEN_PARENT: | |
1118 | inode = get_inode(sb, fid->i32.parent_ino, | |
1119 | (fh_len > 3 ? fid->i32.parent_gen : 0)); | |
1120 | break; | |
1121 | } | |
1122 | ||
4ea3ada2 | 1123 | return d_obtain_alias(inode); |
2596110a CH |
1124 | } |
1125 | EXPORT_SYMBOL_GPL(generic_fh_to_parent); | |
1126 | ||
1b061d92 | 1127 | /** |
ac13a829 FF |
1128 | * __generic_file_fsync - generic fsync implementation for simple filesystems |
1129 | * | |
1b061d92 | 1130 | * @file: file to synchronize |
ac13a829 FF |
1131 | * @start: start offset in bytes |
1132 | * @end: end offset in bytes (inclusive) | |
1b061d92 CH |
1133 | * @datasync: only synchronize essential metadata if true |
1134 | * | |
1135 | * This is a generic implementation of the fsync method for simple | |
1136 | * filesystems which track all non-inode metadata in the buffers list | |
1137 | * hanging off the address_space structure. | |
1138 | */ | |
ac13a829 FF |
1139 | int __generic_file_fsync(struct file *file, loff_t start, loff_t end, |
1140 | int datasync) | |
d5aacad5 | 1141 | { |
7ea80859 | 1142 | struct inode *inode = file->f_mapping->host; |
d5aacad5 AV |
1143 | int err; |
1144 | int ret; | |
1145 | ||
383aa543 | 1146 | err = file_write_and_wait_range(file, start, end); |
02c24a82 JB |
1147 | if (err) |
1148 | return err; | |
1149 | ||
5955102c | 1150 | inode_lock(inode); |
d5aacad5 | 1151 | ret = sync_mapping_buffers(inode->i_mapping); |
0ae45f63 | 1152 | if (!(inode->i_state & I_DIRTY_ALL)) |
02c24a82 | 1153 | goto out; |
d5aacad5 | 1154 | if (datasync && !(inode->i_state & I_DIRTY_DATASYNC)) |
02c24a82 | 1155 | goto out; |
d5aacad5 | 1156 | |
c3765016 | 1157 | err = sync_inode_metadata(inode, 1); |
d5aacad5 AV |
1158 | if (ret == 0) |
1159 | ret = err; | |
ac13a829 | 1160 | |
02c24a82 | 1161 | out: |
5955102c | 1162 | inode_unlock(inode); |
383aa543 JL |
1163 | /* check and advance again to catch errors after syncing out buffers */ |
1164 | err = file_check_and_advance_wb_err(file); | |
1165 | if (ret == 0) | |
1166 | ret = err; | |
1167 | return ret; | |
d5aacad5 | 1168 | } |
ac13a829 FF |
1169 | EXPORT_SYMBOL(__generic_file_fsync); |
1170 | ||
1171 | /** | |
1172 | * generic_file_fsync - generic fsync implementation for simple filesystems | |
1173 | * with flush | |
1174 | * @file: file to synchronize | |
1175 | * @start: start offset in bytes | |
1176 | * @end: end offset in bytes (inclusive) | |
1177 | * @datasync: only synchronize essential metadata if true | |
1178 | * | |
1179 | */ | |
1180 | ||
1181 | int generic_file_fsync(struct file *file, loff_t start, loff_t end, | |
1182 | int datasync) | |
1183 | { | |
1184 | struct inode *inode = file->f_mapping->host; | |
1185 | int err; | |
1186 | ||
1187 | err = __generic_file_fsync(file, start, end, datasync); | |
1188 | if (err) | |
1189 | return err; | |
c6bf3f0e | 1190 | return blkdev_issue_flush(inode->i_sb->s_bdev); |
ac13a829 | 1191 | } |
1b061d92 CH |
1192 | EXPORT_SYMBOL(generic_file_fsync); |
1193 | ||
30ca22c7 PL |
1194 | /** |
1195 | * generic_check_addressable - Check addressability of file system | |
1196 | * @blocksize_bits: log of file system block size | |
1197 | * @num_blocks: number of blocks in file system | |
1198 | * | |
1199 | * Determine whether a file system with @num_blocks blocks (and a | |
1200 | * block size of 2**@blocksize_bits) is addressable by the sector_t | |
1201 | * and page cache of the system. Return 0 if so and -EFBIG otherwise. | |
1202 | */ | |
1203 | int generic_check_addressable(unsigned blocksize_bits, u64 num_blocks) | |
1204 | { | |
1205 | u64 last_fs_block = num_blocks - 1; | |
a33f13ef | 1206 | u64 last_fs_page = |
09cbfeaf | 1207 | last_fs_block >> (PAGE_SHIFT - blocksize_bits); |
30ca22c7 PL |
1208 | |
1209 | if (unlikely(num_blocks == 0)) | |
1210 | return 0; | |
1211 | ||
09cbfeaf | 1212 | if ((blocksize_bits < 9) || (blocksize_bits > PAGE_SHIFT)) |
30ca22c7 PL |
1213 | return -EINVAL; |
1214 | ||
a33f13ef JB |
1215 | if ((last_fs_block > (sector_t)(~0ULL) >> (blocksize_bits - 9)) || |
1216 | (last_fs_page > (pgoff_t)(~0ULL))) { | |
30ca22c7 PL |
1217 | return -EFBIG; |
1218 | } | |
1219 | return 0; | |
1220 | } | |
1221 | EXPORT_SYMBOL(generic_check_addressable); | |
1222 | ||
1b061d92 CH |
1223 | /* |
1224 | * No-op implementation of ->fsync for in-memory filesystems. | |
1225 | */ | |
02c24a82 | 1226 | int noop_fsync(struct file *file, loff_t start, loff_t end, int datasync) |
1b061d92 CH |
1227 | { |
1228 | return 0; | |
1229 | } | |
1b061d92 | 1230 | EXPORT_SYMBOL(noop_fsync); |
87dc800b | 1231 | |
f44c7763 DW |
1232 | ssize_t noop_direct_IO(struct kiocb *iocb, struct iov_iter *iter) |
1233 | { | |
1234 | /* | |
1235 | * iomap based filesystems support direct I/O without need for | |
1236 | * this callback. However, it still needs to be set in | |
1237 | * inode->a_ops so that open/fcntl know that direct I/O is | |
1238 | * generally supported. | |
1239 | */ | |
1240 | return -EINVAL; | |
1241 | } | |
1242 | EXPORT_SYMBOL_GPL(noop_direct_IO); | |
1243 | ||
fceef393 AV |
1244 | /* Because kfree isn't assignment-compatible with void(void*) ;-/ */ |
1245 | void kfree_link(void *p) | |
87dc800b | 1246 | { |
fceef393 | 1247 | kfree(p); |
87dc800b | 1248 | } |
fceef393 | 1249 | EXPORT_SYMBOL(kfree_link); |
6987843f | 1250 | |
6987843f AV |
1251 | struct inode *alloc_anon_inode(struct super_block *s) |
1252 | { | |
1253 | static const struct address_space_operations anon_aops = { | |
46de8b97 | 1254 | .dirty_folio = noop_dirty_folio, |
6987843f AV |
1255 | }; |
1256 | struct inode *inode = new_inode_pseudo(s); | |
1257 | ||
1258 | if (!inode) | |
1259 | return ERR_PTR(-ENOMEM); | |
1260 | ||
1261 | inode->i_ino = get_next_ino(); | |
1262 | inode->i_mapping->a_ops = &anon_aops; | |
1263 | ||
1264 | /* | |
1265 | * Mark the inode dirty from the very beginning, | |
1266 | * that way it will never be moved to the dirty | |
1267 | * list because mark_inode_dirty() will think | |
1268 | * that it already _is_ on the dirty list. | |
1269 | */ | |
1270 | inode->i_state = I_DIRTY; | |
1271 | inode->i_mode = S_IRUSR | S_IWUSR; | |
1272 | inode->i_uid = current_fsuid(); | |
1273 | inode->i_gid = current_fsgid(); | |
1274 | inode->i_flags |= S_PRIVATE; | |
f7f43858 | 1275 | inode->i_atime = inode->i_mtime = inode_set_ctime_current(inode); |
6987843f AV |
1276 | return inode; |
1277 | } | |
1278 | EXPORT_SYMBOL(alloc_anon_inode); | |
1c994a09 JL |
1279 | |
1280 | /** | |
1281 | * simple_nosetlease - generic helper for prohibiting leases | |
1282 | * @filp: file pointer | |
1283 | * @arg: type of lease to obtain | |
1284 | * @flp: new lease supplied for insertion | |
e6f5c789 | 1285 | * @priv: private data for lm_setup operation |
1c994a09 JL |
1286 | * |
1287 | * Generic helper for filesystems that do not wish to allow leases to be set. | |
1288 | * All arguments are ignored and it just returns -EINVAL. | |
1289 | */ | |
1290 | int | |
e6f5c789 JL |
1291 | simple_nosetlease(struct file *filp, long arg, struct file_lock **flp, |
1292 | void **priv) | |
1c994a09 JL |
1293 | { |
1294 | return -EINVAL; | |
1295 | } | |
1296 | EXPORT_SYMBOL(simple_nosetlease); | |
61ba64fc | 1297 | |
6ee9706a EB |
1298 | /** |
1299 | * simple_get_link - generic helper to get the target of "fast" symlinks | |
1300 | * @dentry: not used here | |
1301 | * @inode: the symlink inode | |
1302 | * @done: not used here | |
1303 | * | |
1304 | * Generic helper for filesystems to use for symlink inodes where a pointer to | |
1305 | * the symlink target is stored in ->i_link. NOTE: this isn't normally called, | |
1306 | * since as an optimization the path lookup code uses any non-NULL ->i_link | |
1307 | * directly, without calling ->get_link(). But ->get_link() still must be set, | |
1308 | * to mark the inode_operations as being for a symlink. | |
1309 | * | |
1310 | * Return: the symlink target | |
1311 | */ | |
6b255391 | 1312 | const char *simple_get_link(struct dentry *dentry, struct inode *inode, |
fceef393 | 1313 | struct delayed_call *done) |
61ba64fc | 1314 | { |
6b255391 | 1315 | return inode->i_link; |
61ba64fc | 1316 | } |
6b255391 | 1317 | EXPORT_SYMBOL(simple_get_link); |
61ba64fc AV |
1318 | |
1319 | const struct inode_operations simple_symlink_inode_operations = { | |
6b255391 | 1320 | .get_link = simple_get_link, |
61ba64fc AV |
1321 | }; |
1322 | EXPORT_SYMBOL(simple_symlink_inode_operations); | |
fbabfd0f EB |
1323 | |
1324 | /* | |
1325 | * Operations for a permanently empty directory. | |
1326 | */ | |
1327 | static struct dentry *empty_dir_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags) | |
1328 | { | |
1329 | return ERR_PTR(-ENOENT); | |
1330 | } | |
1331 | ||
b74d24f7 | 1332 | static int empty_dir_getattr(struct mnt_idmap *idmap, |
549c7297 | 1333 | const struct path *path, struct kstat *stat, |
a528d35e | 1334 | u32 request_mask, unsigned int query_flags) |
fbabfd0f | 1335 | { |
a528d35e | 1336 | struct inode *inode = d_inode(path->dentry); |
b74d24f7 | 1337 | generic_fillattr(&nop_mnt_idmap, inode, stat); |
fbabfd0f EB |
1338 | return 0; |
1339 | } | |
1340 | ||
c1632a0f | 1341 | static int empty_dir_setattr(struct mnt_idmap *idmap, |
549c7297 | 1342 | struct dentry *dentry, struct iattr *attr) |
fbabfd0f EB |
1343 | { |
1344 | return -EPERM; | |
1345 | } | |
1346 | ||
fbabfd0f EB |
1347 | static ssize_t empty_dir_listxattr(struct dentry *dentry, char *list, size_t size) |
1348 | { | |
1349 | return -EOPNOTSUPP; | |
1350 | } | |
1351 | ||
1352 | static const struct inode_operations empty_dir_inode_operations = { | |
1353 | .lookup = empty_dir_lookup, | |
1354 | .permission = generic_permission, | |
1355 | .setattr = empty_dir_setattr, | |
1356 | .getattr = empty_dir_getattr, | |
fbabfd0f EB |
1357 | .listxattr = empty_dir_listxattr, |
1358 | }; | |
1359 | ||
1360 | static loff_t empty_dir_llseek(struct file *file, loff_t offset, int whence) | |
1361 | { | |
1362 | /* An empty directory has two entries . and .. at offsets 0 and 1 */ | |
1363 | return generic_file_llseek_size(file, offset, whence, 2, 2); | |
1364 | } | |
1365 | ||
1366 | static int empty_dir_readdir(struct file *file, struct dir_context *ctx) | |
1367 | { | |
1368 | dir_emit_dots(file, ctx); | |
1369 | return 0; | |
1370 | } | |
1371 | ||
1372 | static const struct file_operations empty_dir_operations = { | |
1373 | .llseek = empty_dir_llseek, | |
1374 | .read = generic_read_dir, | |
c51da20c | 1375 | .iterate_shared = empty_dir_readdir, |
fbabfd0f EB |
1376 | .fsync = noop_fsync, |
1377 | }; | |
1378 | ||
1379 | ||
1380 | void make_empty_dir_inode(struct inode *inode) | |
1381 | { | |
1382 | set_nlink(inode, 2); | |
1383 | inode->i_mode = S_IFDIR | S_IRUGO | S_IXUGO; | |
1384 | inode->i_uid = GLOBAL_ROOT_UID; | |
1385 | inode->i_gid = GLOBAL_ROOT_GID; | |
1386 | inode->i_rdev = 0; | |
4b75de86 | 1387 | inode->i_size = 0; |
fbabfd0f EB |
1388 | inode->i_blkbits = PAGE_SHIFT; |
1389 | inode->i_blocks = 0; | |
1390 | ||
1391 | inode->i_op = &empty_dir_inode_operations; | |
f5c24438 | 1392 | inode->i_opflags &= ~IOP_XATTR; |
fbabfd0f EB |
1393 | inode->i_fop = &empty_dir_operations; |
1394 | } | |
1395 | ||
1396 | bool is_empty_dir_inode(struct inode *inode) | |
1397 | { | |
1398 | return (inode->i_fop == &empty_dir_operations) && | |
1399 | (inode->i_op == &empty_dir_inode_operations); | |
1400 | } | |
c843843e | 1401 | |
5298d4bf | 1402 | #if IS_ENABLED(CONFIG_UNICODE) |
c843843e DR |
1403 | /* |
1404 | * Determine if the name of a dentry should be casefolded. | |
1405 | * | |
1406 | * Return: if names will need casefolding | |
1407 | */ | |
1408 | static bool needs_casefold(const struct inode *dir) | |
1409 | { | |
1410 | return IS_CASEFOLDED(dir) && dir->i_sb->s_encoding; | |
1411 | } | |
1412 | ||
1413 | /** | |
1414 | * generic_ci_d_compare - generic d_compare implementation for casefolding filesystems | |
1415 | * @dentry: dentry whose name we are checking against | |
1416 | * @len: len of name of dentry | |
1417 | * @str: str pointer to name of dentry | |
1418 | * @name: Name to compare against | |
1419 | * | |
1420 | * Return: 0 if names match, 1 if mismatch, or -ERRNO | |
1421 | */ | |
794c43f7 EB |
1422 | static int generic_ci_d_compare(const struct dentry *dentry, unsigned int len, |
1423 | const char *str, const struct qstr *name) | |
c843843e DR |
1424 | { |
1425 | const struct dentry *parent = READ_ONCE(dentry->d_parent); | |
1426 | const struct inode *dir = READ_ONCE(parent->d_inode); | |
1427 | const struct super_block *sb = dentry->d_sb; | |
1428 | const struct unicode_map *um = sb->s_encoding; | |
1429 | struct qstr qstr = QSTR_INIT(str, len); | |
1430 | char strbuf[DNAME_INLINE_LEN]; | |
1431 | int ret; | |
1432 | ||
1433 | if (!dir || !needs_casefold(dir)) | |
1434 | goto fallback; | |
1435 | /* | |
1436 | * If the dentry name is stored in-line, then it may be concurrently | |
1437 | * modified by a rename. If this happens, the VFS will eventually retry | |
1438 | * the lookup, so it doesn't matter what ->d_compare() returns. | |
1439 | * However, it's unsafe to call utf8_strncasecmp() with an unstable | |
1440 | * string. Therefore, we have to copy the name into a temporary buffer. | |
1441 | */ | |
1442 | if (len <= DNAME_INLINE_LEN - 1) { | |
1443 | memcpy(strbuf, str, len); | |
1444 | strbuf[len] = 0; | |
1445 | qstr.name = strbuf; | |
1446 | /* prevent compiler from optimizing out the temporary buffer */ | |
1447 | barrier(); | |
1448 | } | |
1449 | ret = utf8_strncasecmp(um, name, &qstr); | |
1450 | if (ret >= 0) | |
1451 | return ret; | |
1452 | ||
1453 | if (sb_has_strict_encoding(sb)) | |
1454 | return -EINVAL; | |
1455 | fallback: | |
1456 | if (len != name->len) | |
1457 | return 1; | |
1458 | return !!memcmp(str, name->name, len); | |
1459 | } | |
c843843e DR |
1460 | |
1461 | /** | |
1462 | * generic_ci_d_hash - generic d_hash implementation for casefolding filesystems | |
1463 | * @dentry: dentry of the parent directory | |
1464 | * @str: qstr of name whose hash we should fill in | |
1465 | * | |
1466 | * Return: 0 if hash was successful or unchanged, and -EINVAL on error | |
1467 | */ | |
794c43f7 | 1468 | static int generic_ci_d_hash(const struct dentry *dentry, struct qstr *str) |
c843843e DR |
1469 | { |
1470 | const struct inode *dir = READ_ONCE(dentry->d_inode); | |
1471 | struct super_block *sb = dentry->d_sb; | |
1472 | const struct unicode_map *um = sb->s_encoding; | |
1473 | int ret = 0; | |
1474 | ||
1475 | if (!dir || !needs_casefold(dir)) | |
1476 | return 0; | |
1477 | ||
1478 | ret = utf8_casefold_hash(um, dentry, str); | |
1479 | if (ret < 0 && sb_has_strict_encoding(sb)) | |
1480 | return -EINVAL; | |
1481 | return 0; | |
1482 | } | |
608af703 DR |
1483 | |
1484 | static const struct dentry_operations generic_ci_dentry_ops = { | |
1485 | .d_hash = generic_ci_d_hash, | |
1486 | .d_compare = generic_ci_d_compare, | |
1487 | }; | |
1488 | #endif | |
1489 | ||
1490 | #ifdef CONFIG_FS_ENCRYPTION | |
1491 | static const struct dentry_operations generic_encrypted_dentry_ops = { | |
1492 | .d_revalidate = fscrypt_d_revalidate, | |
1493 | }; | |
1494 | #endif | |
1495 | ||
5298d4bf | 1496 | #if defined(CONFIG_FS_ENCRYPTION) && IS_ENABLED(CONFIG_UNICODE) |
608af703 DR |
1497 | static const struct dentry_operations generic_encrypted_ci_dentry_ops = { |
1498 | .d_hash = generic_ci_d_hash, | |
1499 | .d_compare = generic_ci_d_compare, | |
1500 | .d_revalidate = fscrypt_d_revalidate, | |
1501 | }; | |
1502 | #endif | |
1503 | ||
1504 | /** | |
1505 | * generic_set_encrypted_ci_d_ops - helper for setting d_ops for given dentry | |
1506 | * @dentry: dentry to set ops on | |
1507 | * | |
1508 | * Casefolded directories need d_hash and d_compare set, so that the dentries | |
1509 | * contained in them are handled case-insensitively. Note that these operations | |
1510 | * are needed on the parent directory rather than on the dentries in it, and | |
1511 | * while the casefolding flag can be toggled on and off on an empty directory, | |
1512 | * dentry_operations can't be changed later. As a result, if the filesystem has | |
1513 | * casefolding support enabled at all, we have to give all dentries the | |
1514 | * casefolding operations even if their inode doesn't have the casefolding flag | |
1515 | * currently (and thus the casefolding ops would be no-ops for now). | |
1516 | * | |
1517 | * Encryption works differently in that the only dentry operation it needs is | |
1518 | * d_revalidate, which it only needs on dentries that have the no-key name flag. | |
1519 | * The no-key flag can't be set "later", so we don't have to worry about that. | |
1520 | * | |
1521 | * Finally, to maximize compatibility with overlayfs (which isn't compatible | |
1522 | * with certain dentry operations) and to avoid taking an unnecessary | |
1523 | * performance hit, we use custom dentry_operations for each possible | |
1524 | * combination rather than always installing all operations. | |
1525 | */ | |
1526 | void generic_set_encrypted_ci_d_ops(struct dentry *dentry) | |
1527 | { | |
1528 | #ifdef CONFIG_FS_ENCRYPTION | |
1529 | bool needs_encrypt_ops = dentry->d_flags & DCACHE_NOKEY_NAME; | |
1530 | #endif | |
5298d4bf | 1531 | #if IS_ENABLED(CONFIG_UNICODE) |
608af703 DR |
1532 | bool needs_ci_ops = dentry->d_sb->s_encoding; |
1533 | #endif | |
5298d4bf | 1534 | #if defined(CONFIG_FS_ENCRYPTION) && IS_ENABLED(CONFIG_UNICODE) |
608af703 DR |
1535 | if (needs_encrypt_ops && needs_ci_ops) { |
1536 | d_set_d_op(dentry, &generic_encrypted_ci_dentry_ops); | |
1537 | return; | |
1538 | } | |
c843843e | 1539 | #endif |
608af703 DR |
1540 | #ifdef CONFIG_FS_ENCRYPTION |
1541 | if (needs_encrypt_ops) { | |
1542 | d_set_d_op(dentry, &generic_encrypted_dentry_ops); | |
1543 | return; | |
1544 | } | |
1545 | #endif | |
5298d4bf | 1546 | #if IS_ENABLED(CONFIG_UNICODE) |
608af703 DR |
1547 | if (needs_ci_ops) { |
1548 | d_set_d_op(dentry, &generic_ci_dentry_ops); | |
1549 | return; | |
1550 | } | |
1551 | #endif | |
1552 | } | |
1553 | EXPORT_SYMBOL(generic_set_encrypted_ci_d_ops); | |
5ca14835 AM |
1554 | |
1555 | /** | |
1556 | * inode_maybe_inc_iversion - increments i_version | |
1557 | * @inode: inode with the i_version that should be updated | |
1558 | * @force: increment the counter even if it's not necessary? | |
1559 | * | |
1560 | * Every time the inode is modified, the i_version field must be seen to have | |
1561 | * changed by any observer. | |
1562 | * | |
1563 | * If "force" is set or the QUERIED flag is set, then ensure that we increment | |
1564 | * the value, and clear the queried flag. | |
1565 | * | |
1566 | * In the common case where neither is set, then we can return "false" without | |
1567 | * updating i_version. | |
1568 | * | |
1569 | * If this function returns false, and no other metadata has changed, then we | |
1570 | * can avoid logging the metadata. | |
1571 | */ | |
1572 | bool inode_maybe_inc_iversion(struct inode *inode, bool force) | |
1573 | { | |
1574 | u64 cur, new; | |
1575 | ||
1576 | /* | |
1577 | * The i_version field is not strictly ordered with any other inode | |
1578 | * information, but the legacy inode_inc_iversion code used a spinlock | |
1579 | * to serialize increments. | |
1580 | * | |
1581 | * Here, we add full memory barriers to ensure that any de-facto | |
1582 | * ordering with other info is preserved. | |
1583 | * | |
1584 | * This barrier pairs with the barrier in inode_query_iversion() | |
1585 | */ | |
1586 | smp_mb(); | |
1587 | cur = inode_peek_iversion_raw(inode); | |
1588 | do { | |
1589 | /* If flag is clear then we needn't do anything */ | |
1590 | if (!force && !(cur & I_VERSION_QUERIED)) | |
1591 | return false; | |
1592 | ||
1593 | /* Since lowest bit is flag, add 2 to avoid it */ | |
1594 | new = (cur & ~I_VERSION_QUERIED) + I_VERSION_INCREMENT; | |
1595 | } while (!atomic64_try_cmpxchg(&inode->i_version, &cur, new)); | |
1596 | return true; | |
1597 | } | |
1598 | EXPORT_SYMBOL(inode_maybe_inc_iversion); | |
c5bc1b3f JL |
1599 | |
1600 | /** | |
1601 | * inode_query_iversion - read i_version for later use | |
1602 | * @inode: inode from which i_version should be read | |
1603 | * | |
1604 | * Read the inode i_version counter. This should be used by callers that wish | |
1605 | * to store the returned i_version for later comparison. This will guarantee | |
1606 | * that a later query of the i_version will result in a different value if | |
1607 | * anything has changed. | |
1608 | * | |
1609 | * In this implementation, we fetch the current value, set the QUERIED flag and | |
1610 | * then try to swap it into place with a cmpxchg, if it wasn't already set. If | |
1611 | * that fails, we try again with the newly fetched value from the cmpxchg. | |
1612 | */ | |
1613 | u64 inode_query_iversion(struct inode *inode) | |
1614 | { | |
1615 | u64 cur, new; | |
1616 | ||
1617 | cur = inode_peek_iversion_raw(inode); | |
1618 | do { | |
1619 | /* If flag is already set, then no need to swap */ | |
1620 | if (cur & I_VERSION_QUERIED) { | |
1621 | /* | |
1622 | * This barrier (and the implicit barrier in the | |
1623 | * cmpxchg below) pairs with the barrier in | |
1624 | * inode_maybe_inc_iversion(). | |
1625 | */ | |
1626 | smp_mb(); | |
1627 | break; | |
1628 | } | |
1629 | ||
1630 | new = cur | I_VERSION_QUERIED; | |
1631 | } while (!atomic64_try_cmpxchg(&inode->i_version, &cur, new)); | |
1632 | return cur >> I_VERSION_QUERIED_SHIFT; | |
1633 | } | |
1634 | EXPORT_SYMBOL(inode_query_iversion); | |
44fff0fa CH |
1635 | |
1636 | ssize_t direct_write_fallback(struct kiocb *iocb, struct iov_iter *iter, | |
1637 | ssize_t direct_written, ssize_t buffered_written) | |
1638 | { | |
1639 | struct address_space *mapping = iocb->ki_filp->f_mapping; | |
1640 | loff_t pos = iocb->ki_pos - buffered_written; | |
1641 | loff_t end = iocb->ki_pos - 1; | |
1642 | int err; | |
1643 | ||
1644 | /* | |
1645 | * If the buffered write fallback returned an error, we want to return | |
1646 | * the number of bytes which were written by direct I/O, or the error | |
1647 | * code if that was zero. | |
1648 | * | |
1649 | * Note that this differs from normal direct-io semantics, which will | |
1650 | * return -EFOO even if some bytes were written. | |
1651 | */ | |
1652 | if (unlikely(buffered_written < 0)) { | |
1653 | if (direct_written) | |
1654 | return direct_written; | |
1655 | return buffered_written; | |
1656 | } | |
1657 | ||
1658 | /* | |
1659 | * We need to ensure that the page cache pages are written to disk and | |
1660 | * invalidated to preserve the expected O_DIRECT semantics. | |
1661 | */ | |
1662 | err = filemap_write_and_wait_range(mapping, pos, end); | |
1663 | if (err < 0) { | |
1664 | /* | |
1665 | * We don't know how much we wrote, so just return the number of | |
1666 | * bytes which were direct-written | |
1667 | */ | |
1668 | if (direct_written) | |
1669 | return direct_written; | |
1670 | return err; | |
1671 | } | |
1672 | invalidate_mapping_pages(mapping, pos >> PAGE_SHIFT, end >> PAGE_SHIFT); | |
1673 | return direct_written + buffered_written; | |
1674 | } | |
1675 | EXPORT_SYMBOL_GPL(direct_write_fallback); |