]>
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> |
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> | |
b28ddcc3 | 26 | #include <linux/pidfs.h> |
7cf34c76 | 27 | |
7c0f6ba6 | 28 | #include <linux/uaccess.h> |
1da177e4 | 29 | |
a4464dbc AV |
30 | #include "internal.h" |
31 | ||
b74d24f7 | 32 | int simple_getattr(struct mnt_idmap *idmap, const struct path *path, |
549c7297 CB |
33 | struct kstat *stat, u32 request_mask, |
34 | unsigned int query_flags) | |
1da177e4 | 35 | { |
a528d35e | 36 | struct inode *inode = d_inode(path->dentry); |
0d72b928 | 37 | generic_fillattr(&nop_mnt_idmap, request_mask, inode, stat); |
09cbfeaf | 38 | stat->blocks = inode->i_mapping->nrpages << (PAGE_SHIFT - 9); |
1da177e4 LT |
39 | return 0; |
40 | } | |
12f38872 | 41 | EXPORT_SYMBOL(simple_getattr); |
1da177e4 | 42 | |
726c3342 | 43 | int simple_statfs(struct dentry *dentry, struct kstatfs *buf) |
1da177e4 | 44 | { |
ae62bcb5 AG |
45 | u64 id = huge_encode_dev(dentry->d_sb->s_dev); |
46 | ||
47 | buf->f_fsid = u64_to_fsid(id); | |
726c3342 | 48 | buf->f_type = dentry->d_sb->s_magic; |
09cbfeaf | 49 | buf->f_bsize = PAGE_SIZE; |
1da177e4 LT |
50 | buf->f_namelen = NAME_MAX; |
51 | return 0; | |
52 | } | |
12f38872 | 53 | EXPORT_SYMBOL(simple_statfs); |
1da177e4 LT |
54 | |
55 | /* | |
56 | * Retaining negative dentries for an in-memory filesystem just wastes | |
57 | * memory and lookup time: arrange for them to be deleted immediately. | |
58 | */ | |
b26d4cd3 | 59 | int always_delete_dentry(const struct dentry *dentry) |
1da177e4 LT |
60 | { |
61 | return 1; | |
62 | } | |
b26d4cd3 AV |
63 | EXPORT_SYMBOL(always_delete_dentry); |
64 | ||
65 | const struct dentry_operations simple_dentry_operations = { | |
66 | .d_delete = always_delete_dentry, | |
67 | }; | |
68 | EXPORT_SYMBOL(simple_dentry_operations); | |
1da177e4 LT |
69 | |
70 | /* | |
71 | * Lookup the data. This is trivial - if the dentry didn't already | |
72 | * exist, we know it is negative. Set d_op to delete negative dentries. | |
73 | */ | |
00cd8dd3 | 74 | struct dentry *simple_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags) |
1da177e4 | 75 | { |
1da177e4 LT |
76 | if (dentry->d_name.len > NAME_MAX) |
77 | return ERR_PTR(-ENAMETOOLONG); | |
74931da7 AV |
78 | if (!dentry->d_sb->s_d_op) |
79 | d_set_d_op(dentry, &simple_dentry_operations); | |
1da177e4 LT |
80 | d_add(dentry, NULL); |
81 | return NULL; | |
82 | } | |
12f38872 | 83 | EXPORT_SYMBOL(simple_lookup); |
1da177e4 | 84 | |
1da177e4 LT |
85 | int dcache_dir_open(struct inode *inode, struct file *file) |
86 | { | |
ba65dc5e | 87 | file->private_data = d_alloc_cursor(file->f_path.dentry); |
1da177e4 LT |
88 | |
89 | return file->private_data ? 0 : -ENOMEM; | |
90 | } | |
12f38872 | 91 | EXPORT_SYMBOL(dcache_dir_open); |
1da177e4 LT |
92 | |
93 | int dcache_dir_close(struct inode *inode, struct file *file) | |
94 | { | |
95 | dput(file->private_data); | |
96 | return 0; | |
97 | } | |
12f38872 | 98 | EXPORT_SYMBOL(dcache_dir_close); |
1da177e4 | 99 | |
4f42c1b5 | 100 | /* parent is locked at least shared */ |
d4f4de5e AV |
101 | /* |
102 | * Returns an element of siblings' list. | |
103 | * We are looking for <count>th positive after <p>; if | |
26b6c984 AV |
104 | * found, dentry is grabbed and returned to caller. |
105 | * If no such element exists, NULL is returned. | |
d4f4de5e | 106 | */ |
26b6c984 | 107 | static struct dentry *scan_positives(struct dentry *cursor, |
da549bdd | 108 | struct hlist_node **p, |
d4f4de5e | 109 | loff_t count, |
26b6c984 | 110 | struct dentry *last) |
4f42c1b5 | 111 | { |
d4f4de5e AV |
112 | struct dentry *dentry = cursor->d_parent, *found = NULL; |
113 | ||
114 | spin_lock(&dentry->d_lock); | |
da549bdd AV |
115 | while (*p) { |
116 | struct dentry *d = hlist_entry(*p, struct dentry, d_sib); | |
117 | p = &d->d_sib.next; | |
d4f4de5e AV |
118 | // we must at least skip cursors, to avoid livelocks |
119 | if (d->d_flags & DCACHE_DENTRY_CURSOR) | |
120 | continue; | |
121 | if (simple_positive(d) && !--count) { | |
122 | spin_lock_nested(&d->d_lock, DENTRY_D_LOCK_NESTED); | |
123 | if (simple_positive(d)) | |
124 | found = dget_dlock(d); | |
125 | spin_unlock(&d->d_lock); | |
126 | if (likely(found)) | |
127 | break; | |
128 | count = 1; | |
129 | } | |
130 | if (need_resched()) { | |
da549bdd AV |
131 | if (!hlist_unhashed(&cursor->d_sib)) |
132 | __hlist_del(&cursor->d_sib); | |
133 | hlist_add_behind(&cursor->d_sib, &d->d_sib); | |
134 | p = &cursor->d_sib.next; | |
d4f4de5e AV |
135 | spin_unlock(&dentry->d_lock); |
136 | cond_resched(); | |
137 | spin_lock(&dentry->d_lock); | |
4f42c1b5 AV |
138 | } |
139 | } | |
d4f4de5e | 140 | spin_unlock(&dentry->d_lock); |
26b6c984 AV |
141 | dput(last); |
142 | return found; | |
4f42c1b5 AV |
143 | } |
144 | ||
965c8e59 | 145 | loff_t dcache_dir_lseek(struct file *file, loff_t offset, int whence) |
1da177e4 | 146 | { |
2fd6b7f5 | 147 | struct dentry *dentry = file->f_path.dentry; |
965c8e59 | 148 | switch (whence) { |
1da177e4 LT |
149 | case 1: |
150 | offset += file->f_pos; | |
df561f66 | 151 | fallthrough; |
1da177e4 LT |
152 | case 0: |
153 | if (offset >= 0) | |
154 | break; | |
df561f66 | 155 | fallthrough; |
1da177e4 | 156 | default: |
1da177e4 LT |
157 | return -EINVAL; |
158 | } | |
159 | if (offset != file->f_pos) { | |
d4f4de5e AV |
160 | struct dentry *cursor = file->private_data; |
161 | struct dentry *to = NULL; | |
d4f4de5e | 162 | |
d4f4de5e AV |
163 | inode_lock_shared(dentry->d_inode); |
164 | ||
26b6c984 | 165 | if (offset > 2) |
da549bdd | 166 | to = scan_positives(cursor, &dentry->d_children.first, |
26b6c984 AV |
167 | offset - 2, NULL); |
168 | spin_lock(&dentry->d_lock); | |
da549bdd | 169 | hlist_del_init(&cursor->d_sib); |
26b6c984 | 170 | if (to) |
da549bdd | 171 | hlist_add_behind(&cursor->d_sib, &to->d_sib); |
26b6c984 | 172 | spin_unlock(&dentry->d_lock); |
d4f4de5e AV |
173 | dput(to); |
174 | ||
26b6c984 AV |
175 | file->f_pos = offset; |
176 | ||
d4f4de5e | 177 | inode_unlock_shared(dentry->d_inode); |
1da177e4 | 178 | } |
1da177e4 LT |
179 | return offset; |
180 | } | |
12f38872 | 181 | EXPORT_SYMBOL(dcache_dir_lseek); |
1da177e4 | 182 | |
1da177e4 LT |
183 | /* |
184 | * Directory is locked and all positive dentries in it are safe, since | |
185 | * for ramfs-type trees they can't go away without unlink() or rmdir(), | |
186 | * both impossible due to the lock on directory. | |
187 | */ | |
188 | ||
5f99f4e7 | 189 | int dcache_readdir(struct file *file, struct dir_context *ctx) |
1da177e4 | 190 | { |
5f99f4e7 AV |
191 | struct dentry *dentry = file->f_path.dentry; |
192 | struct dentry *cursor = file->private_data; | |
d4f4de5e | 193 | struct dentry *next = NULL; |
da549bdd | 194 | struct hlist_node **p; |
1da177e4 | 195 | |
5f99f4e7 AV |
196 | if (!dir_emit_dots(file, ctx)) |
197 | return 0; | |
5f99f4e7 | 198 | |
4f42c1b5 | 199 | if (ctx->pos == 2) |
da549bdd | 200 | p = &dentry->d_children.first; |
26b6c984 | 201 | else |
da549bdd | 202 | p = &cursor->d_sib.next; |
d4f4de5e | 203 | |
26b6c984 | 204 | while ((next = scan_positives(cursor, p, 1, next)) != NULL) { |
5f99f4e7 | 205 | if (!dir_emit(ctx, next->d_name.name, next->d_name.len, |
364595a6 JL |
206 | d_inode(next)->i_ino, |
207 | fs_umode_to_dtype(d_inode(next)->i_mode))) | |
4f42c1b5 | 208 | break; |
5f99f4e7 | 209 | ctx->pos++; |
da549bdd | 210 | p = &next->d_sib.next; |
1da177e4 | 211 | } |
d4f4de5e | 212 | spin_lock(&dentry->d_lock); |
da549bdd | 213 | hlist_del_init(&cursor->d_sib); |
26b6c984 | 214 | if (next) |
da549bdd | 215 | hlist_add_before(&cursor->d_sib, &next->d_sib); |
d4f4de5e AV |
216 | spin_unlock(&dentry->d_lock); |
217 | dput(next); | |
218 | ||
1da177e4 LT |
219 | return 0; |
220 | } | |
12f38872 | 221 | EXPORT_SYMBOL(dcache_readdir); |
1da177e4 LT |
222 | |
223 | ssize_t generic_read_dir(struct file *filp, char __user *buf, size_t siz, loff_t *ppos) | |
224 | { | |
225 | return -EISDIR; | |
226 | } | |
12f38872 | 227 | EXPORT_SYMBOL(generic_read_dir); |
1da177e4 | 228 | |
4b6f5d20 | 229 | const struct file_operations simple_dir_operations = { |
1da177e4 LT |
230 | .open = dcache_dir_open, |
231 | .release = dcache_dir_close, | |
232 | .llseek = dcache_dir_lseek, | |
233 | .read = generic_read_dir, | |
4e82901c | 234 | .iterate_shared = dcache_readdir, |
1b061d92 | 235 | .fsync = noop_fsync, |
1da177e4 | 236 | }; |
12f38872 | 237 | EXPORT_SYMBOL(simple_dir_operations); |
1da177e4 | 238 | |
92e1d5be | 239 | const struct inode_operations simple_dir_inode_operations = { |
1da177e4 LT |
240 | .lookup = simple_lookup, |
241 | }; | |
12f38872 | 242 | EXPORT_SYMBOL(simple_dir_inode_operations); |
1da177e4 | 243 | |
7beea725 CL |
244 | /* 0 is '.', 1 is '..', so always start with offset 2 or more */ |
245 | enum { | |
246 | DIR_OFFSET_MIN = 2, | |
247 | }; | |
248 | ||
0e4a8621 | 249 | static void offset_set(struct dentry *dentry, long offset) |
6faddda6 | 250 | { |
0e4a8621 | 251 | dentry->d_fsdata = (void *)offset; |
6faddda6 CL |
252 | } |
253 | ||
0e4a8621 | 254 | static long dentry2offset(struct dentry *dentry) |
6faddda6 | 255 | { |
0e4a8621 | 256 | return (long)dentry->d_fsdata; |
6faddda6 CL |
257 | } |
258 | ||
0e4a8621 | 259 | static struct lock_class_key simple_offset_lock_class; |
bbaef797 | 260 | |
6faddda6 CL |
261 | /** |
262 | * simple_offset_init - initialize an offset_ctx | |
263 | * @octx: directory offset map to be initialized | |
264 | * | |
265 | */ | |
266 | void simple_offset_init(struct offset_ctx *octx) | |
267 | { | |
0e4a8621 CL |
268 | mt_init_flags(&octx->mt, MT_FLAGS_ALLOC_RANGE); |
269 | lockdep_set_class(&octx->mt.ma_lock, &simple_offset_lock_class); | |
7beea725 | 270 | octx->next_offset = DIR_OFFSET_MIN; |
6faddda6 CL |
271 | } |
272 | ||
273 | /** | |
274 | * simple_offset_add - Add an entry to a directory's offset map | |
275 | * @octx: directory offset ctx to be updated | |
276 | * @dentry: new dentry being added | |
277 | * | |
0e4a8621 | 278 | * Returns zero on success. @octx and the dentry's offset are updated. |
6faddda6 CL |
279 | * Otherwise, a negative errno value is returned. |
280 | */ | |
281 | int simple_offset_add(struct offset_ctx *octx, struct dentry *dentry) | |
282 | { | |
0e4a8621 | 283 | unsigned long offset; |
6faddda6 CL |
284 | int ret; |
285 | ||
286 | if (dentry2offset(dentry) != 0) | |
287 | return -EBUSY; | |
288 | ||
0e4a8621 CL |
289 | ret = mtree_alloc_cyclic(&octx->mt, &offset, dentry, DIR_OFFSET_MIN, |
290 | LONG_MAX, &octx->next_offset, GFP_KERNEL); | |
6faddda6 CL |
291 | if (ret < 0) |
292 | return ret; | |
293 | ||
294 | offset_set(dentry, offset); | |
295 | return 0; | |
296 | } | |
297 | ||
298 | /** | |
299 | * simple_offset_remove - Remove an entry to a directory's offset map | |
300 | * @octx: directory offset ctx to be updated | |
301 | * @dentry: dentry being removed | |
302 | * | |
303 | */ | |
304 | void simple_offset_remove(struct offset_ctx *octx, struct dentry *dentry) | |
305 | { | |
0e4a8621 | 306 | long offset; |
6faddda6 CL |
307 | |
308 | offset = dentry2offset(dentry); | |
309 | if (offset == 0) | |
310 | return; | |
311 | ||
0e4a8621 | 312 | mtree_erase(&octx->mt, offset); |
6faddda6 CL |
313 | offset_set(dentry, 0); |
314 | } | |
315 | ||
ecba88a3 CL |
316 | /** |
317 | * simple_offset_empty - Check if a dentry can be unlinked | |
318 | * @dentry: dentry to be tested | |
319 | * | |
320 | * Returns 0 if @dentry is a non-empty directory; otherwise returns 1. | |
321 | */ | |
322 | int simple_offset_empty(struct dentry *dentry) | |
323 | { | |
324 | struct inode *inode = d_inode(dentry); | |
325 | struct offset_ctx *octx; | |
326 | struct dentry *child; | |
327 | unsigned long index; | |
328 | int ret = 1; | |
329 | ||
330 | if (!inode || !S_ISDIR(inode->i_mode)) | |
331 | return ret; | |
332 | ||
333 | index = DIR_OFFSET_MIN; | |
334 | octx = inode->i_op->get_offset_ctx(inode); | |
0e4a8621 | 335 | mt_for_each(&octx->mt, child, index, LONG_MAX) { |
ecba88a3 CL |
336 | spin_lock(&child->d_lock); |
337 | if (simple_positive(child)) { | |
338 | spin_unlock(&child->d_lock); | |
339 | ret = 0; | |
340 | break; | |
341 | } | |
342 | spin_unlock(&child->d_lock); | |
343 | } | |
344 | ||
345 | return ret; | |
346 | } | |
347 | ||
6faddda6 CL |
348 | /** |
349 | * simple_offset_rename_exchange - exchange rename with directory offsets | |
350 | * @old_dir: parent of dentry being moved | |
351 | * @old_dentry: dentry being moved | |
352 | * @new_dir: destination parent | |
353 | * @new_dentry: destination dentry | |
354 | * | |
355 | * Returns zero on success. Otherwise a negative errno is returned and the | |
356 | * rename is rolled back. | |
357 | */ | |
358 | int simple_offset_rename_exchange(struct inode *old_dir, | |
359 | struct dentry *old_dentry, | |
360 | struct inode *new_dir, | |
361 | struct dentry *new_dentry) | |
362 | { | |
363 | struct offset_ctx *old_ctx = old_dir->i_op->get_offset_ctx(old_dir); | |
364 | struct offset_ctx *new_ctx = new_dir->i_op->get_offset_ctx(new_dir); | |
0e4a8621 CL |
365 | long old_index = dentry2offset(old_dentry); |
366 | long new_index = dentry2offset(new_dentry); | |
6faddda6 CL |
367 | int ret; |
368 | ||
369 | simple_offset_remove(old_ctx, old_dentry); | |
370 | simple_offset_remove(new_ctx, new_dentry); | |
371 | ||
372 | ret = simple_offset_add(new_ctx, old_dentry); | |
373 | if (ret) | |
374 | goto out_restore; | |
375 | ||
376 | ret = simple_offset_add(old_ctx, new_dentry); | |
377 | if (ret) { | |
378 | simple_offset_remove(new_ctx, old_dentry); | |
379 | goto out_restore; | |
380 | } | |
381 | ||
382 | ret = simple_rename_exchange(old_dir, old_dentry, new_dir, new_dentry); | |
383 | if (ret) { | |
384 | simple_offset_remove(new_ctx, old_dentry); | |
385 | simple_offset_remove(old_ctx, new_dentry); | |
386 | goto out_restore; | |
387 | } | |
388 | return 0; | |
389 | ||
390 | out_restore: | |
391 | offset_set(old_dentry, old_index); | |
0e4a8621 | 392 | mtree_store(&old_ctx->mt, old_index, old_dentry, GFP_KERNEL); |
6faddda6 | 393 | offset_set(new_dentry, new_index); |
0e4a8621 | 394 | mtree_store(&new_ctx->mt, new_index, new_dentry, GFP_KERNEL); |
6faddda6 CL |
395 | return ret; |
396 | } | |
397 | ||
398 | /** | |
399 | * simple_offset_destroy - Release offset map | |
400 | * @octx: directory offset ctx that is about to be destroyed | |
401 | * | |
402 | * During fs teardown (eg. umount), a directory's offset map might still | |
403 | * contain entries. xa_destroy() cleans out anything that remains. | |
404 | */ | |
405 | void simple_offset_destroy(struct offset_ctx *octx) | |
406 | { | |
0e4a8621 | 407 | mtree_destroy(&octx->mt); |
6faddda6 CL |
408 | } |
409 | ||
410 | /** | |
411 | * offset_dir_llseek - Advance the read position of a directory descriptor | |
412 | * @file: an open directory whose position is to be updated | |
413 | * @offset: a byte offset | |
414 | * @whence: enumerator describing the starting position for this update | |
415 | * | |
416 | * SEEK_END, SEEK_DATA, and SEEK_HOLE are not supported for directories. | |
417 | * | |
418 | * Returns the updated read position if successful; otherwise a | |
419 | * negative errno is returned and the read position remains unchanged. | |
420 | */ | |
421 | static loff_t offset_dir_llseek(struct file *file, loff_t offset, int whence) | |
422 | { | |
423 | switch (whence) { | |
424 | case SEEK_CUR: | |
425 | offset += file->f_pos; | |
426 | fallthrough; | |
427 | case SEEK_SET: | |
428 | if (offset >= 0) | |
429 | break; | |
430 | fallthrough; | |
431 | default: | |
432 | return -EINVAL; | |
433 | } | |
434 | ||
796432ef CL |
435 | /* In this case, ->private_data is protected by f_pos_lock */ |
436 | file->private_data = NULL; | |
0e4a8621 | 437 | return vfs_setpos(file, offset, LONG_MAX); |
6faddda6 CL |
438 | } |
439 | ||
3f6d8106 | 440 | static struct dentry *offset_find_next(struct offset_ctx *octx, loff_t offset) |
6faddda6 | 441 | { |
0e4a8621 | 442 | MA_STATE(mas, &octx->mt, offset, offset); |
6faddda6 CL |
443 | struct dentry *child, *found = NULL; |
444 | ||
445 | rcu_read_lock(); | |
0e4a8621 | 446 | child = mas_find(&mas, LONG_MAX); |
6faddda6 CL |
447 | if (!child) |
448 | goto out; | |
2be4f05a | 449 | spin_lock(&child->d_lock); |
6faddda6 CL |
450 | if (simple_positive(child)) |
451 | found = dget_dlock(child); | |
452 | spin_unlock(&child->d_lock); | |
453 | out: | |
454 | rcu_read_unlock(); | |
455 | return found; | |
456 | } | |
457 | ||
458 | static bool offset_dir_emit(struct dir_context *ctx, struct dentry *dentry) | |
459 | { | |
6faddda6 | 460 | struct inode *inode = d_inode(dentry); |
0e4a8621 | 461 | long offset = dentry2offset(dentry); |
6faddda6 CL |
462 | |
463 | return ctx->actor(ctx, dentry->d_name.name, dentry->d_name.len, offset, | |
464 | inode->i_ino, fs_umode_to_dtype(inode->i_mode)); | |
465 | } | |
466 | ||
796432ef | 467 | static void *offset_iterate_dir(struct inode *inode, struct dir_context *ctx) |
6faddda6 | 468 | { |
3f6d8106 | 469 | struct offset_ctx *octx = inode->i_op->get_offset_ctx(inode); |
6faddda6 CL |
470 | struct dentry *dentry; |
471 | ||
472 | while (true) { | |
3f6d8106 | 473 | dentry = offset_find_next(octx, ctx->pos); |
6faddda6 | 474 | if (!dentry) |
796432ef | 475 | return ERR_PTR(-ENOENT); |
6faddda6 CL |
476 | |
477 | if (!offset_dir_emit(ctx, dentry)) { | |
478 | dput(dentry); | |
479 | break; | |
480 | } | |
481 | ||
3f6d8106 | 482 | ctx->pos = dentry2offset(dentry) + 1; |
6faddda6 | 483 | dput(dentry); |
6faddda6 | 484 | } |
796432ef | 485 | return NULL; |
6faddda6 CL |
486 | } |
487 | ||
488 | /** | |
489 | * offset_readdir - Emit entries starting at offset @ctx->pos | |
490 | * @file: an open directory to iterate over | |
491 | * @ctx: directory iteration context | |
492 | * | |
493 | * Caller must hold @file's i_rwsem to prevent insertion or removal of | |
494 | * entries during this call. | |
495 | * | |
496 | * On entry, @ctx->pos contains an offset that represents the first entry | |
497 | * to be read from the directory. | |
498 | * | |
499 | * The operation continues until there are no more entries to read, or | |
500 | * until the ctx->actor indicates there is no more space in the caller's | |
501 | * output buffer. | |
502 | * | |
503 | * On return, @ctx->pos contains an offset that will read the next entry | |
2be4f05a | 504 | * in this directory when offset_readdir() is called again with @ctx. |
6faddda6 CL |
505 | * |
506 | * Return values: | |
507 | * %0 - Complete | |
508 | */ | |
509 | static int offset_readdir(struct file *file, struct dir_context *ctx) | |
510 | { | |
511 | struct dentry *dir = file->f_path.dentry; | |
512 | ||
513 | lockdep_assert_held(&d_inode(dir)->i_rwsem); | |
514 | ||
515 | if (!dir_emit_dots(file, ctx)) | |
516 | return 0; | |
517 | ||
796432ef | 518 | /* In this case, ->private_data is protected by f_pos_lock */ |
7beea725 | 519 | if (ctx->pos == DIR_OFFSET_MIN) |
796432ef CL |
520 | file->private_data = NULL; |
521 | else if (file->private_data == ERR_PTR(-ENOENT)) | |
522 | return 0; | |
523 | file->private_data = offset_iterate_dir(d_inode(dir), ctx); | |
6faddda6 CL |
524 | return 0; |
525 | } | |
526 | ||
527 | const struct file_operations simple_offset_dir_operations = { | |
528 | .llseek = offset_dir_llseek, | |
529 | .iterate_shared = offset_readdir, | |
530 | .read = generic_read_dir, | |
531 | .fsync = noop_fsync, | |
532 | }; | |
533 | ||
a3d1e7eb AV |
534 | static struct dentry *find_next_child(struct dentry *parent, struct dentry *prev) |
535 | { | |
da549bdd | 536 | struct dentry *child = NULL, *d; |
a3d1e7eb AV |
537 | |
538 | spin_lock(&parent->d_lock); | |
da549bdd AV |
539 | d = prev ? d_next_sibling(prev) : d_first_child(parent); |
540 | hlist_for_each_entry_from(d, d_sib) { | |
a3d1e7eb AV |
541 | if (simple_positive(d)) { |
542 | spin_lock_nested(&d->d_lock, DENTRY_D_LOCK_NESTED); | |
543 | if (simple_positive(d)) | |
544 | child = dget_dlock(d); | |
545 | spin_unlock(&d->d_lock); | |
546 | if (likely(child)) | |
547 | break; | |
548 | } | |
549 | } | |
550 | spin_unlock(&parent->d_lock); | |
551 | dput(prev); | |
552 | return child; | |
553 | } | |
554 | ||
555 | void simple_recursive_removal(struct dentry *dentry, | |
556 | void (*callback)(struct dentry *)) | |
557 | { | |
558 | struct dentry *this = dget(dentry); | |
559 | while (true) { | |
560 | struct dentry *victim = NULL, *child; | |
561 | struct inode *inode = this->d_inode; | |
562 | ||
563 | inode_lock(inode); | |
564 | if (d_is_dir(this)) | |
565 | inode->i_flags |= S_DEAD; | |
566 | while ((child = find_next_child(this, victim)) == NULL) { | |
567 | // kill and ascend | |
568 | // update metadata while it's still locked | |
f7f43858 | 569 | inode_set_ctime_current(inode); |
a3d1e7eb AV |
570 | clear_nlink(inode); |
571 | inode_unlock(inode); | |
572 | victim = this; | |
573 | this = this->d_parent; | |
574 | inode = this->d_inode; | |
575 | inode_lock(inode); | |
576 | if (simple_positive(victim)) { | |
577 | d_invalidate(victim); // avoid lost mounts | |
578 | if (d_is_dir(victim)) | |
579 | fsnotify_rmdir(inode, victim); | |
580 | else | |
581 | fsnotify_unlink(inode, victim); | |
582 | if (callback) | |
583 | callback(victim); | |
584 | dput(victim); // unpin it | |
585 | } | |
586 | if (victim == dentry) { | |
077c212f JL |
587 | inode_set_mtime_to_ts(inode, |
588 | inode_set_ctime_current(inode)); | |
a3d1e7eb AV |
589 | if (d_is_dir(dentry)) |
590 | drop_nlink(inode); | |
591 | inode_unlock(inode); | |
592 | dput(dentry); | |
593 | return; | |
594 | } | |
595 | } | |
596 | inode_unlock(inode); | |
597 | this = child; | |
598 | } | |
599 | } | |
600 | EXPORT_SYMBOL(simple_recursive_removal); | |
601 | ||
759b9775 HD |
602 | static const struct super_operations simple_super_operations = { |
603 | .statfs = simple_statfs, | |
604 | }; | |
605 | ||
db2c246a | 606 | static int pseudo_fs_fill_super(struct super_block *s, struct fs_context *fc) |
1da177e4 | 607 | { |
31d6d5ce | 608 | struct pseudo_fs_context *ctx = fc->fs_private; |
1da177e4 | 609 | struct inode *root; |
1da177e4 | 610 | |
89a4eb4b | 611 | s->s_maxbytes = MAX_LFS_FILESIZE; |
3971e1a9 AN |
612 | s->s_blocksize = PAGE_SIZE; |
613 | s->s_blocksize_bits = PAGE_SHIFT; | |
8d9e46d8 AV |
614 | s->s_magic = ctx->magic; |
615 | s->s_op = ctx->ops ?: &simple_super_operations; | |
616 | s->s_xattr = ctx->xattr; | |
1da177e4 LT |
617 | s->s_time_gran = 1; |
618 | root = new_inode(s); | |
619 | if (!root) | |
db2c246a DH |
620 | return -ENOMEM; |
621 | ||
1a1c9bb4 JL |
622 | /* |
623 | * since this is the first inode, make it number 1. New inodes created | |
624 | * after this must take care not to collide with it (by passing | |
625 | * max_reserved of 1 to iunique). | |
626 | */ | |
627 | root->i_ino = 1; | |
1da177e4 | 628 | root->i_mode = S_IFDIR | S_IRUSR | S_IWUSR; |
077c212f | 629 | simple_inode_init_ts(root); |
8d9e46d8 AV |
630 | s->s_root = d_make_root(root); |
631 | if (!s->s_root) | |
db2c246a | 632 | return -ENOMEM; |
8d9e46d8 | 633 | s->s_d_op = ctx->dops; |
31d6d5ce | 634 | return 0; |
db2c246a | 635 | } |
8d9e46d8 | 636 | |
db2c246a DH |
637 | static int pseudo_fs_get_tree(struct fs_context *fc) |
638 | { | |
2ac295d4 | 639 | return get_tree_nodev(fc, pseudo_fs_fill_super); |
31d6d5ce DH |
640 | } |
641 | ||
642 | static void pseudo_fs_free(struct fs_context *fc) | |
643 | { | |
644 | kfree(fc->fs_private); | |
645 | } | |
646 | ||
647 | static const struct fs_context_operations pseudo_fs_context_ops = { | |
648 | .free = pseudo_fs_free, | |
649 | .get_tree = pseudo_fs_get_tree, | |
650 | }; | |
651 | ||
652 | /* | |
653 | * Common helper for pseudo-filesystems (sockfs, pipefs, bdev - stuff that | |
654 | * will never be mountable) | |
655 | */ | |
656 | struct pseudo_fs_context *init_pseudo(struct fs_context *fc, | |
657 | unsigned long magic) | |
658 | { | |
659 | struct pseudo_fs_context *ctx; | |
660 | ||
661 | ctx = kzalloc(sizeof(struct pseudo_fs_context), GFP_KERNEL); | |
662 | if (likely(ctx)) { | |
663 | ctx->magic = magic; | |
664 | fc->fs_private = ctx; | |
665 | fc->ops = &pseudo_fs_context_ops; | |
db2c246a DH |
666 | fc->sb_flags |= SB_NOUSER; |
667 | fc->global = true; | |
1da177e4 | 668 | } |
31d6d5ce | 669 | return ctx; |
1da177e4 | 670 | } |
31d6d5ce | 671 | EXPORT_SYMBOL(init_pseudo); |
1da177e4 | 672 | |
20955e89 SB |
673 | int simple_open(struct inode *inode, struct file *file) |
674 | { | |
675 | if (inode->i_private) | |
676 | file->private_data = inode->i_private; | |
677 | return 0; | |
678 | } | |
12f38872 | 679 | EXPORT_SYMBOL(simple_open); |
20955e89 | 680 | |
1da177e4 LT |
681 | int simple_link(struct dentry *old_dentry, struct inode *dir, struct dentry *dentry) |
682 | { | |
dea655c2 | 683 | struct inode *inode = d_inode(old_dentry); |
1da177e4 | 684 | |
077c212f JL |
685 | inode_set_mtime_to_ts(dir, |
686 | inode_set_ctime_to_ts(dir, inode_set_ctime_current(inode))); | |
d8c76e6f | 687 | inc_nlink(inode); |
7de9c6ee | 688 | ihold(inode); |
1da177e4 LT |
689 | dget(dentry); |
690 | d_instantiate(dentry, inode); | |
691 | return 0; | |
692 | } | |
12f38872 | 693 | EXPORT_SYMBOL(simple_link); |
1da177e4 | 694 | |
1da177e4 LT |
695 | int simple_empty(struct dentry *dentry) |
696 | { | |
697 | struct dentry *child; | |
698 | int ret = 0; | |
699 | ||
2fd6b7f5 | 700 | spin_lock(&dentry->d_lock); |
da549bdd | 701 | hlist_for_each_entry(child, &dentry->d_children, d_sib) { |
da502956 NP |
702 | spin_lock_nested(&child->d_lock, DENTRY_D_LOCK_NESTED); |
703 | if (simple_positive(child)) { | |
704 | spin_unlock(&child->d_lock); | |
1da177e4 | 705 | goto out; |
da502956 NP |
706 | } |
707 | spin_unlock(&child->d_lock); | |
708 | } | |
1da177e4 LT |
709 | ret = 1; |
710 | out: | |
2fd6b7f5 | 711 | spin_unlock(&dentry->d_lock); |
1da177e4 LT |
712 | return ret; |
713 | } | |
12f38872 | 714 | EXPORT_SYMBOL(simple_empty); |
1da177e4 LT |
715 | |
716 | int simple_unlink(struct inode *dir, struct dentry *dentry) | |
717 | { | |
dea655c2 | 718 | struct inode *inode = d_inode(dentry); |
1da177e4 | 719 | |
077c212f JL |
720 | inode_set_mtime_to_ts(dir, |
721 | inode_set_ctime_to_ts(dir, inode_set_ctime_current(inode))); | |
9a53c3a7 | 722 | drop_nlink(inode); |
1da177e4 LT |
723 | dput(dentry); |
724 | return 0; | |
725 | } | |
12f38872 | 726 | EXPORT_SYMBOL(simple_unlink); |
1da177e4 LT |
727 | |
728 | int simple_rmdir(struct inode *dir, struct dentry *dentry) | |
729 | { | |
730 | if (!simple_empty(dentry)) | |
731 | return -ENOTEMPTY; | |
732 | ||
dea655c2 | 733 | drop_nlink(d_inode(dentry)); |
1da177e4 | 734 | simple_unlink(dir, dentry); |
9a53c3a7 | 735 | drop_nlink(dir); |
1da177e4 LT |
736 | return 0; |
737 | } | |
12f38872 | 738 | EXPORT_SYMBOL(simple_rmdir); |
1da177e4 | 739 | |
0c476792 JL |
740 | /** |
741 | * simple_rename_timestamp - update the various inode timestamps for rename | |
742 | * @old_dir: old parent directory | |
743 | * @old_dentry: dentry that is being renamed | |
744 | * @new_dir: new parent directory | |
745 | * @new_dentry: target for rename | |
746 | * | |
747 | * POSIX mandates that the old and new parent directories have their ctime and | |
748 | * mtime updated, and that inodes of @old_dentry and @new_dentry (if any), have | |
749 | * their ctime updated. | |
750 | */ | |
751 | void simple_rename_timestamp(struct inode *old_dir, struct dentry *old_dentry, | |
752 | struct inode *new_dir, struct dentry *new_dentry) | |
753 | { | |
754 | struct inode *newino = d_inode(new_dentry); | |
755 | ||
077c212f | 756 | inode_set_mtime_to_ts(old_dir, inode_set_ctime_current(old_dir)); |
0c476792 | 757 | if (new_dir != old_dir) |
077c212f JL |
758 | inode_set_mtime_to_ts(new_dir, |
759 | inode_set_ctime_current(new_dir)); | |
0c476792 JL |
760 | inode_set_ctime_current(d_inode(old_dentry)); |
761 | if (newino) | |
762 | inode_set_ctime_current(newino); | |
763 | } | |
764 | EXPORT_SYMBOL_GPL(simple_rename_timestamp); | |
765 | ||
6429e463 LB |
766 | int simple_rename_exchange(struct inode *old_dir, struct dentry *old_dentry, |
767 | struct inode *new_dir, struct dentry *new_dentry) | |
768 | { | |
769 | bool old_is_dir = d_is_dir(old_dentry); | |
770 | bool new_is_dir = d_is_dir(new_dentry); | |
771 | ||
772 | if (old_dir != new_dir && old_is_dir != new_is_dir) { | |
773 | if (old_is_dir) { | |
774 | drop_nlink(old_dir); | |
775 | inc_nlink(new_dir); | |
776 | } else { | |
777 | drop_nlink(new_dir); | |
778 | inc_nlink(old_dir); | |
779 | } | |
780 | } | |
0c476792 | 781 | simple_rename_timestamp(old_dir, old_dentry, new_dir, new_dentry); |
6429e463 LB |
782 | return 0; |
783 | } | |
784 | EXPORT_SYMBOL_GPL(simple_rename_exchange); | |
785 | ||
e18275ae | 786 | int simple_rename(struct mnt_idmap *idmap, struct inode *old_dir, |
549c7297 CB |
787 | struct dentry *old_dentry, struct inode *new_dir, |
788 | struct dentry *new_dentry, unsigned int flags) | |
1da177e4 | 789 | { |
e36cb0b8 | 790 | int they_are_dirs = d_is_dir(old_dentry); |
1da177e4 | 791 | |
3871cb8c | 792 | if (flags & ~(RENAME_NOREPLACE | RENAME_EXCHANGE)) |
e0e0be8a MS |
793 | return -EINVAL; |
794 | ||
3871cb8c LB |
795 | if (flags & RENAME_EXCHANGE) |
796 | return simple_rename_exchange(old_dir, old_dentry, new_dir, new_dentry); | |
797 | ||
1da177e4 LT |
798 | if (!simple_empty(new_dentry)) |
799 | return -ENOTEMPTY; | |
800 | ||
dea655c2 | 801 | if (d_really_is_positive(new_dentry)) { |
1da177e4 | 802 | simple_unlink(new_dir, new_dentry); |
841590ce | 803 | if (they_are_dirs) { |
dea655c2 | 804 | drop_nlink(d_inode(new_dentry)); |
9a53c3a7 | 805 | drop_nlink(old_dir); |
841590ce | 806 | } |
1da177e4 | 807 | } else if (they_are_dirs) { |
9a53c3a7 | 808 | drop_nlink(old_dir); |
d8c76e6f | 809 | inc_nlink(new_dir); |
1da177e4 LT |
810 | } |
811 | ||
0c476792 | 812 | simple_rename_timestamp(old_dir, old_dentry, new_dir, new_dentry); |
1da177e4 LT |
813 | return 0; |
814 | } | |
12f38872 | 815 | EXPORT_SYMBOL(simple_rename); |
1da177e4 | 816 | |
7bb46a67 | 817 | /** |
eef2380c | 818 | * simple_setattr - setattr for simple filesystem |
c1632a0f | 819 | * @idmap: idmap of the target mount |
7bb46a67 NP |
820 | * @dentry: dentry |
821 | * @iattr: iattr structure | |
822 | * | |
823 | * Returns 0 on success, -error on failure. | |
824 | * | |
eef2380c CH |
825 | * simple_setattr is a simple ->setattr implementation without a proper |
826 | * implementation of size changes. | |
827 | * | |
828 | * It can either be used for in-memory filesystems or special files | |
829 | * on simple regular filesystems. Anything that needs to change on-disk | |
830 | * or wire state on size changes needs its own setattr method. | |
7bb46a67 | 831 | */ |
c1632a0f | 832 | int simple_setattr(struct mnt_idmap *idmap, struct dentry *dentry, |
549c7297 | 833 | struct iattr *iattr) |
7bb46a67 | 834 | { |
dea655c2 | 835 | struct inode *inode = d_inode(dentry); |
7bb46a67 NP |
836 | int error; |
837 | ||
c1632a0f | 838 | error = setattr_prepare(idmap, dentry, iattr); |
7bb46a67 NP |
839 | if (error) |
840 | return error; | |
841 | ||
2c27c65e CH |
842 | if (iattr->ia_valid & ATTR_SIZE) |
843 | truncate_setsize(inode, iattr->ia_size); | |
c1632a0f | 844 | setattr_copy(idmap, inode, iattr); |
eef2380c CH |
845 | mark_inode_dirty(inode); |
846 | return 0; | |
7bb46a67 NP |
847 | } |
848 | EXPORT_SYMBOL(simple_setattr); | |
849 | ||
a77f580a | 850 | static int simple_read_folio(struct file *file, struct folio *folio) |
1da177e4 | 851 | { |
a77f580a MWO |
852 | folio_zero_range(folio, 0, folio_size(folio)); |
853 | flush_dcache_folio(folio); | |
854 | folio_mark_uptodate(folio); | |
855 | folio_unlock(folio); | |
1da177e4 LT |
856 | return 0; |
857 | } | |
858 | ||
afddba49 | 859 | int simple_write_begin(struct file *file, struct address_space *mapping, |
9d6b0cd7 | 860 | loff_t pos, unsigned len, |
afddba49 NP |
861 | struct page **pagep, void **fsdata) |
862 | { | |
5522d9f7 | 863 | struct folio *folio; |
afddba49 | 864 | |
5522d9f7 MWO |
865 | folio = __filemap_get_folio(mapping, pos / PAGE_SIZE, FGP_WRITEBEGIN, |
866 | mapping_gfp_mask(mapping)); | |
867 | if (IS_ERR(folio)) | |
868 | return PTR_ERR(folio); | |
afddba49 | 869 | |
5522d9f7 | 870 | *pagep = &folio->page; |
afddba49 | 871 | |
5522d9f7 MWO |
872 | if (!folio_test_uptodate(folio) && (len != folio_size(folio))) { |
873 | size_t from = offset_in_folio(folio, pos); | |
193cf4b9 | 874 | |
5522d9f7 MWO |
875 | folio_zero_segments(folio, 0, from, |
876 | from + len, folio_size(folio)); | |
193cf4b9 BH |
877 | } |
878 | return 0; | |
afddba49 | 879 | } |
12f38872 | 880 | EXPORT_SYMBOL(simple_write_begin); |
afddba49 | 881 | |
ad2a722f BH |
882 | /** |
883 | * simple_write_end - .write_end helper for non-block-device FSes | |
8e88bfba | 884 | * @file: See .write_end of address_space_operations |
ad2a722f BH |
885 | * @mapping: " |
886 | * @pos: " | |
887 | * @len: " | |
888 | * @copied: " | |
889 | * @page: " | |
890 | * @fsdata: " | |
891 | * | |
892 | * simple_write_end does the minimum needed for updating a page after writing is | |
893 | * done. It has the same API signature as the .write_end of | |
894 | * address_space_operations vector. So it can just be set onto .write_end for | |
895 | * FSes that don't need any other processing. i_mutex is assumed to be held. | |
896 | * Block based filesystems should use generic_write_end(). | |
897 | * NOTE: Even though i_size might get updated by this function, mark_inode_dirty | |
898 | * is not called, so a filesystem that actually does store data in .write_inode | |
899 | * should extend on what's done here with a call to mark_inode_dirty() in the | |
900 | * case that i_size has changed. | |
04fff641 | 901 | * |
a77f580a | 902 | * Use *ONLY* with simple_read_folio() |
ad2a722f | 903 | */ |
c1e3dbe9 | 904 | static int simple_write_end(struct file *file, struct address_space *mapping, |
afddba49 NP |
905 | loff_t pos, unsigned len, unsigned copied, |
906 | struct page *page, void *fsdata) | |
907 | { | |
5522d9f7 MWO |
908 | struct folio *folio = page_folio(page); |
909 | struct inode *inode = folio->mapping->host; | |
ad2a722f | 910 | loff_t last_pos = pos + copied; |
afddba49 | 911 | |
5522d9f7 MWO |
912 | /* zero the stale part of the folio if we did a short copy */ |
913 | if (!folio_test_uptodate(folio)) { | |
04fff641 | 914 | if (copied < len) { |
5522d9f7 | 915 | size_t from = offset_in_folio(folio, pos); |
afddba49 | 916 | |
5522d9f7 | 917 | folio_zero_range(folio, from + copied, len - copied); |
04fff641 | 918 | } |
5522d9f7 | 919 | folio_mark_uptodate(folio); |
04fff641 | 920 | } |
ad2a722f BH |
921 | /* |
922 | * No need to use i_size_read() here, the i_size | |
923 | * cannot change under us because we hold the i_mutex. | |
924 | */ | |
925 | if (last_pos > inode->i_size) | |
926 | i_size_write(inode, last_pos); | |
afddba49 | 927 | |
5522d9f7 MWO |
928 | folio_mark_dirty(folio); |
929 | folio_unlock(folio); | |
930 | folio_put(folio); | |
afddba49 NP |
931 | |
932 | return copied; | |
933 | } | |
c1e3dbe9 CH |
934 | |
935 | /* | |
936 | * Provides ramfs-style behavior: data in the pagecache, but no writeback. | |
937 | */ | |
938 | const struct address_space_operations ram_aops = { | |
a77f580a | 939 | .read_folio = simple_read_folio, |
c1e3dbe9 CH |
940 | .write_begin = simple_write_begin, |
941 | .write_end = simple_write_end, | |
46de8b97 | 942 | .dirty_folio = noop_dirty_folio, |
c1e3dbe9 CH |
943 | }; |
944 | EXPORT_SYMBOL(ram_aops); | |
afddba49 | 945 | |
1a1c9bb4 JL |
946 | /* |
947 | * the inodes created here are not hashed. If you use iunique to generate | |
948 | * unique inode values later for this filesystem, then you must take care | |
949 | * to pass it an appropriate max_reserved value to avoid collisions. | |
950 | */ | |
7d683a09 | 951 | int simple_fill_super(struct super_block *s, unsigned long magic, |
cda37124 | 952 | const struct tree_descr *files) |
1da177e4 | 953 | { |
1da177e4 | 954 | struct inode *inode; |
1da177e4 LT |
955 | struct dentry *dentry; |
956 | int i; | |
957 | ||
09cbfeaf KS |
958 | s->s_blocksize = PAGE_SIZE; |
959 | s->s_blocksize_bits = PAGE_SHIFT; | |
1da177e4 | 960 | s->s_magic = magic; |
759b9775 | 961 | s->s_op = &simple_super_operations; |
1da177e4 LT |
962 | s->s_time_gran = 1; |
963 | ||
964 | inode = new_inode(s); | |
965 | if (!inode) | |
966 | return -ENOMEM; | |
1a1c9bb4 JL |
967 | /* |
968 | * because the root inode is 1, the files array must not contain an | |
969 | * entry at index 1 | |
970 | */ | |
971 | inode->i_ino = 1; | |
1da177e4 | 972 | inode->i_mode = S_IFDIR | 0755; |
077c212f | 973 | simple_inode_init_ts(inode); |
1da177e4 LT |
974 | inode->i_op = &simple_dir_inode_operations; |
975 | inode->i_fop = &simple_dir_operations; | |
bfe86848 | 976 | set_nlink(inode, 2); |
715cd66a AV |
977 | s->s_root = d_make_root(inode); |
978 | if (!s->s_root) | |
1da177e4 | 979 | return -ENOMEM; |
1da177e4 LT |
980 | for (i = 0; !files->name || files->name[0]; i++, files++) { |
981 | if (!files->name) | |
982 | continue; | |
1a1c9bb4 JL |
983 | |
984 | /* warn if it tries to conflict with the root inode */ | |
985 | if (unlikely(i == 1)) | |
986 | printk(KERN_WARNING "%s: %s passed in a files array" | |
987 | "with an index of 1!\n", __func__, | |
988 | s->s_type->name); | |
989 | ||
715cd66a | 990 | dentry = d_alloc_name(s->s_root, files->name); |
1da177e4 | 991 | if (!dentry) |
715cd66a | 992 | return -ENOMEM; |
1da177e4 | 993 | inode = new_inode(s); |
32096ea1 KK |
994 | if (!inode) { |
995 | dput(dentry); | |
715cd66a | 996 | return -ENOMEM; |
32096ea1 | 997 | } |
1da177e4 | 998 | inode->i_mode = S_IFREG | files->mode; |
077c212f | 999 | simple_inode_init_ts(inode); |
1da177e4 LT |
1000 | inode->i_fop = files->ops; |
1001 | inode->i_ino = i; | |
1002 | d_add(dentry, inode); | |
1003 | } | |
1da177e4 | 1004 | return 0; |
1da177e4 | 1005 | } |
12f38872 | 1006 | EXPORT_SYMBOL(simple_fill_super); |
1da177e4 LT |
1007 | |
1008 | static DEFINE_SPINLOCK(pin_fs_lock); | |
1009 | ||
1f5ce9e9 | 1010 | int simple_pin_fs(struct file_system_type *type, struct vfsmount **mount, int *count) |
1da177e4 LT |
1011 | { |
1012 | struct vfsmount *mnt = NULL; | |
1013 | spin_lock(&pin_fs_lock); | |
1014 | if (unlikely(!*mount)) { | |
1015 | spin_unlock(&pin_fs_lock); | |
1751e8a6 | 1016 | mnt = vfs_kern_mount(type, SB_KERNMOUNT, type->name, NULL); |
1da177e4 LT |
1017 | if (IS_ERR(mnt)) |
1018 | return PTR_ERR(mnt); | |
1019 | spin_lock(&pin_fs_lock); | |
1020 | if (!*mount) | |
1021 | *mount = mnt; | |
1022 | } | |
1023 | mntget(*mount); | |
1024 | ++*count; | |
1025 | spin_unlock(&pin_fs_lock); | |
1026 | mntput(mnt); | |
1027 | return 0; | |
1028 | } | |
12f38872 | 1029 | EXPORT_SYMBOL(simple_pin_fs); |
1da177e4 LT |
1030 | |
1031 | void simple_release_fs(struct vfsmount **mount, int *count) | |
1032 | { | |
1033 | struct vfsmount *mnt; | |
1034 | spin_lock(&pin_fs_lock); | |
1035 | mnt = *mount; | |
1036 | if (!--*count) | |
1037 | *mount = NULL; | |
1038 | spin_unlock(&pin_fs_lock); | |
1039 | mntput(mnt); | |
1040 | } | |
12f38872 | 1041 | EXPORT_SYMBOL(simple_release_fs); |
1da177e4 | 1042 | |
6d1029b5 AM |
1043 | /** |
1044 | * simple_read_from_buffer - copy data from the buffer to user space | |
1045 | * @to: the user space buffer to read to | |
1046 | * @count: the maximum number of bytes to read | |
1047 | * @ppos: the current position in the buffer | |
1048 | * @from: the buffer to read from | |
1049 | * @available: the size of the buffer | |
1050 | * | |
1051 | * The simple_read_from_buffer() function reads up to @count bytes from the | |
1052 | * buffer @from at offset @ppos into the user space address starting at @to. | |
1053 | * | |
1054 | * On success, the number of bytes read is returned and the offset @ppos is | |
1055 | * advanced by this number, or negative value is returned on error. | |
1056 | **/ | |
1da177e4 LT |
1057 | ssize_t simple_read_from_buffer(void __user *to, size_t count, loff_t *ppos, |
1058 | const void *from, size_t available) | |
1059 | { | |
1060 | loff_t pos = *ppos; | |
14be2746 SR |
1061 | size_t ret; |
1062 | ||
1da177e4 LT |
1063 | if (pos < 0) |
1064 | return -EINVAL; | |
14be2746 | 1065 | if (pos >= available || !count) |
1da177e4 LT |
1066 | return 0; |
1067 | if (count > available - pos) | |
1068 | count = available - pos; | |
14be2746 SR |
1069 | ret = copy_to_user(to, from + pos, count); |
1070 | if (ret == count) | |
1da177e4 | 1071 | return -EFAULT; |
14be2746 | 1072 | count -= ret; |
1da177e4 LT |
1073 | *ppos = pos + count; |
1074 | return count; | |
1075 | } | |
12f38872 | 1076 | EXPORT_SYMBOL(simple_read_from_buffer); |
1da177e4 | 1077 | |
6a727b43 JS |
1078 | /** |
1079 | * simple_write_to_buffer - copy data from user space to the buffer | |
1080 | * @to: the buffer to write to | |
1081 | * @available: the size of the buffer | |
1082 | * @ppos: the current position in the buffer | |
1083 | * @from: the user space buffer to read from | |
1084 | * @count: the maximum number of bytes to read | |
1085 | * | |
1086 | * The simple_write_to_buffer() function reads up to @count bytes from the user | |
1087 | * space address starting at @from into the buffer @to at offset @ppos. | |
1088 | * | |
1089 | * On success, the number of bytes written is returned and the offset @ppos is | |
1090 | * advanced by this number, or negative value is returned on error. | |
1091 | **/ | |
1092 | ssize_t simple_write_to_buffer(void *to, size_t available, loff_t *ppos, | |
1093 | const void __user *from, size_t count) | |
1094 | { | |
1095 | loff_t pos = *ppos; | |
1096 | size_t res; | |
1097 | ||
1098 | if (pos < 0) | |
1099 | return -EINVAL; | |
1100 | if (pos >= available || !count) | |
1101 | return 0; | |
1102 | if (count > available - pos) | |
1103 | count = available - pos; | |
1104 | res = copy_from_user(to + pos, from, count); | |
1105 | if (res == count) | |
1106 | return -EFAULT; | |
1107 | count -= res; | |
1108 | *ppos = pos + count; | |
1109 | return count; | |
1110 | } | |
12f38872 | 1111 | EXPORT_SYMBOL(simple_write_to_buffer); |
6a727b43 | 1112 | |
6d1029b5 AM |
1113 | /** |
1114 | * memory_read_from_buffer - copy data from the buffer | |
1115 | * @to: the kernel space buffer to read to | |
1116 | * @count: the maximum number of bytes to read | |
1117 | * @ppos: the current position in the buffer | |
1118 | * @from: the buffer to read from | |
1119 | * @available: the size of the buffer | |
1120 | * | |
1121 | * The memory_read_from_buffer() function reads up to @count bytes from the | |
1122 | * buffer @from at offset @ppos into the kernel space address starting at @to. | |
1123 | * | |
1124 | * On success, the number of bytes read is returned and the offset @ppos is | |
1125 | * advanced by this number, or negative value is returned on error. | |
1126 | **/ | |
93b07113 AM |
1127 | ssize_t memory_read_from_buffer(void *to, size_t count, loff_t *ppos, |
1128 | const void *from, size_t available) | |
1129 | { | |
1130 | loff_t pos = *ppos; | |
1131 | ||
1132 | if (pos < 0) | |
1133 | return -EINVAL; | |
1134 | if (pos >= available) | |
1135 | return 0; | |
1136 | if (count > available - pos) | |
1137 | count = available - pos; | |
1138 | memcpy(to, from + pos, count); | |
1139 | *ppos = pos + count; | |
1140 | ||
1141 | return count; | |
1142 | } | |
12f38872 | 1143 | EXPORT_SYMBOL(memory_read_from_buffer); |
93b07113 | 1144 | |
1da177e4 LT |
1145 | /* |
1146 | * Transaction based IO. | |
1147 | * The file expects a single write which triggers the transaction, and then | |
1148 | * possibly a read which collects the result - which is stored in a | |
1149 | * file-local buffer. | |
1150 | */ | |
76791ab2 IM |
1151 | |
1152 | void simple_transaction_set(struct file *file, size_t n) | |
1153 | { | |
1154 | struct simple_transaction_argresp *ar = file->private_data; | |
1155 | ||
1156 | BUG_ON(n > SIMPLE_TRANSACTION_LIMIT); | |
1157 | ||
1158 | /* | |
1159 | * The barrier ensures that ar->size will really remain zero until | |
1160 | * ar->data is ready for reading. | |
1161 | */ | |
1162 | smp_mb(); | |
1163 | ar->size = n; | |
1164 | } | |
12f38872 | 1165 | EXPORT_SYMBOL(simple_transaction_set); |
76791ab2 | 1166 | |
1da177e4 LT |
1167 | char *simple_transaction_get(struct file *file, const char __user *buf, size_t size) |
1168 | { | |
1169 | struct simple_transaction_argresp *ar; | |
1170 | static DEFINE_SPINLOCK(simple_transaction_lock); | |
1171 | ||
1172 | if (size > SIMPLE_TRANSACTION_LIMIT - 1) | |
1173 | return ERR_PTR(-EFBIG); | |
1174 | ||
1175 | ar = (struct simple_transaction_argresp *)get_zeroed_page(GFP_KERNEL); | |
1176 | if (!ar) | |
1177 | return ERR_PTR(-ENOMEM); | |
1178 | ||
1179 | spin_lock(&simple_transaction_lock); | |
1180 | ||
1181 | /* only one write allowed per open */ | |
1182 | if (file->private_data) { | |
1183 | spin_unlock(&simple_transaction_lock); | |
1184 | free_page((unsigned long)ar); | |
1185 | return ERR_PTR(-EBUSY); | |
1186 | } | |
1187 | ||
1188 | file->private_data = ar; | |
1189 | ||
1190 | spin_unlock(&simple_transaction_lock); | |
1191 | ||
1192 | if (copy_from_user(ar->data, buf, size)) | |
1193 | return ERR_PTR(-EFAULT); | |
1194 | ||
1195 | return ar->data; | |
1196 | } | |
12f38872 | 1197 | EXPORT_SYMBOL(simple_transaction_get); |
1da177e4 LT |
1198 | |
1199 | ssize_t simple_transaction_read(struct file *file, char __user *buf, size_t size, loff_t *pos) | |
1200 | { | |
1201 | struct simple_transaction_argresp *ar = file->private_data; | |
1202 | ||
1203 | if (!ar) | |
1204 | return 0; | |
1205 | return simple_read_from_buffer(buf, size, pos, ar->data, ar->size); | |
1206 | } | |
12f38872 | 1207 | EXPORT_SYMBOL(simple_transaction_read); |
1da177e4 LT |
1208 | |
1209 | int simple_transaction_release(struct inode *inode, struct file *file) | |
1210 | { | |
1211 | free_page((unsigned long)file->private_data); | |
1212 | return 0; | |
1213 | } | |
12f38872 | 1214 | EXPORT_SYMBOL(simple_transaction_release); |
1da177e4 | 1215 | |
acaefc25 AB |
1216 | /* Simple attribute files */ |
1217 | ||
1218 | struct simple_attr { | |
8b88b099 CH |
1219 | int (*get)(void *, u64 *); |
1220 | int (*set)(void *, u64); | |
acaefc25 AB |
1221 | char get_buf[24]; /* enough to store a u64 and "\n\0" */ |
1222 | char set_buf[24]; | |
1223 | void *data; | |
1224 | const char *fmt; /* format for read operation */ | |
7cf34c76 | 1225 | struct mutex mutex; /* protects access to these buffers */ |
acaefc25 AB |
1226 | }; |
1227 | ||
1228 | /* simple_attr_open is called by an actual attribute open file operation | |
1229 | * to set the attribute specific access operations. */ | |
1230 | int simple_attr_open(struct inode *inode, struct file *file, | |
8b88b099 | 1231 | int (*get)(void *, u64 *), int (*set)(void *, u64), |
acaefc25 AB |
1232 | const char *fmt) |
1233 | { | |
1234 | struct simple_attr *attr; | |
1235 | ||
a65cab7d | 1236 | attr = kzalloc(sizeof(*attr), GFP_KERNEL); |
acaefc25 AB |
1237 | if (!attr) |
1238 | return -ENOMEM; | |
1239 | ||
1240 | attr->get = get; | |
1241 | attr->set = set; | |
8e18e294 | 1242 | attr->data = inode->i_private; |
acaefc25 | 1243 | attr->fmt = fmt; |
7cf34c76 | 1244 | mutex_init(&attr->mutex); |
acaefc25 AB |
1245 | |
1246 | file->private_data = attr; | |
1247 | ||
1248 | return nonseekable_open(inode, file); | |
1249 | } | |
12f38872 | 1250 | EXPORT_SYMBOL_GPL(simple_attr_open); |
acaefc25 | 1251 | |
74bedc4d | 1252 | int simple_attr_release(struct inode *inode, struct file *file) |
acaefc25 AB |
1253 | { |
1254 | kfree(file->private_data); | |
1255 | return 0; | |
1256 | } | |
12f38872 | 1257 | EXPORT_SYMBOL_GPL(simple_attr_release); /* GPL-only? This? Really? */ |
acaefc25 AB |
1258 | |
1259 | /* read from the buffer that is filled with the get function */ | |
1260 | ssize_t simple_attr_read(struct file *file, char __user *buf, | |
1261 | size_t len, loff_t *ppos) | |
1262 | { | |
1263 | struct simple_attr *attr; | |
1264 | size_t size; | |
1265 | ssize_t ret; | |
1266 | ||
1267 | attr = file->private_data; | |
1268 | ||
1269 | if (!attr->get) | |
1270 | return -EACCES; | |
1271 | ||
9261303a CH |
1272 | ret = mutex_lock_interruptible(&attr->mutex); |
1273 | if (ret) | |
1274 | return ret; | |
1275 | ||
a65cab7d EB |
1276 | if (*ppos && attr->get_buf[0]) { |
1277 | /* continued read */ | |
acaefc25 | 1278 | size = strlen(attr->get_buf); |
a65cab7d EB |
1279 | } else { |
1280 | /* first read */ | |
8b88b099 CH |
1281 | u64 val; |
1282 | ret = attr->get(attr->data, &val); | |
1283 | if (ret) | |
1284 | goto out; | |
1285 | ||
acaefc25 | 1286 | size = scnprintf(attr->get_buf, sizeof(attr->get_buf), |
8b88b099 CH |
1287 | attr->fmt, (unsigned long long)val); |
1288 | } | |
acaefc25 AB |
1289 | |
1290 | ret = simple_read_from_buffer(buf, len, ppos, attr->get_buf, size); | |
8b88b099 | 1291 | out: |
7cf34c76 | 1292 | mutex_unlock(&attr->mutex); |
acaefc25 AB |
1293 | return ret; |
1294 | } | |
12f38872 | 1295 | EXPORT_SYMBOL_GPL(simple_attr_read); |
acaefc25 AB |
1296 | |
1297 | /* interpret the buffer as a number to call the set function with */ | |
2e41f274 AM |
1298 | static ssize_t simple_attr_write_xsigned(struct file *file, const char __user *buf, |
1299 | size_t len, loff_t *ppos, bool is_signed) | |
acaefc25 AB |
1300 | { |
1301 | struct simple_attr *attr; | |
488dac0c | 1302 | unsigned long long val; |
acaefc25 AB |
1303 | size_t size; |
1304 | ssize_t ret; | |
1305 | ||
1306 | attr = file->private_data; | |
acaefc25 AB |
1307 | if (!attr->set) |
1308 | return -EACCES; | |
1309 | ||
9261303a CH |
1310 | ret = mutex_lock_interruptible(&attr->mutex); |
1311 | if (ret) | |
1312 | return ret; | |
1313 | ||
acaefc25 AB |
1314 | ret = -EFAULT; |
1315 | size = min(sizeof(attr->set_buf) - 1, len); | |
1316 | if (copy_from_user(attr->set_buf, buf, size)) | |
1317 | goto out; | |
1318 | ||
acaefc25 | 1319 | attr->set_buf[size] = '\0'; |
2e41f274 AM |
1320 | if (is_signed) |
1321 | ret = kstrtoll(attr->set_buf, 0, &val); | |
1322 | else | |
1323 | ret = kstrtoull(attr->set_buf, 0, &val); | |
488dac0c YY |
1324 | if (ret) |
1325 | goto out; | |
05cc0cee WF |
1326 | ret = attr->set(attr->data, val); |
1327 | if (ret == 0) | |
1328 | ret = len; /* on success, claim we got the whole input */ | |
acaefc25 | 1329 | out: |
7cf34c76 | 1330 | mutex_unlock(&attr->mutex); |
acaefc25 AB |
1331 | return ret; |
1332 | } | |
2e41f274 AM |
1333 | |
1334 | ssize_t simple_attr_write(struct file *file, const char __user *buf, | |
1335 | size_t len, loff_t *ppos) | |
1336 | { | |
1337 | return simple_attr_write_xsigned(file, buf, len, ppos, false); | |
1338 | } | |
12f38872 | 1339 | EXPORT_SYMBOL_GPL(simple_attr_write); |
acaefc25 | 1340 | |
2e41f274 AM |
1341 | ssize_t simple_attr_write_signed(struct file *file, const char __user *buf, |
1342 | size_t len, loff_t *ppos) | |
1343 | { | |
1344 | return simple_attr_write_xsigned(file, buf, len, ppos, true); | |
1345 | } | |
1346 | EXPORT_SYMBOL_GPL(simple_attr_write_signed); | |
1347 | ||
d9e5d922 AG |
1348 | /** |
1349 | * generic_encode_ino32_fh - generic export_operations->encode_fh function | |
1350 | * @inode: the object to encode | |
1351 | * @fh: where to store the file handle fragment | |
1352 | * @max_len: maximum length to store there (in 4 byte units) | |
1353 | * @parent: parent directory inode, if wanted | |
1354 | * | |
1355 | * This generic encode_fh function assumes that the 32 inode number | |
1356 | * is suitable for locating an inode, and that the generation number | |
1357 | * can be used to check that it is still valid. It places them in the | |
1358 | * filehandle fragment where export_decode_fh expects to find them. | |
1359 | */ | |
1360 | int generic_encode_ino32_fh(struct inode *inode, __u32 *fh, int *max_len, | |
1361 | struct inode *parent) | |
1362 | { | |
1363 | struct fid *fid = (void *)fh; | |
1364 | int len = *max_len; | |
1365 | int type = FILEID_INO32_GEN; | |
1366 | ||
1367 | if (parent && (len < 4)) { | |
1368 | *max_len = 4; | |
1369 | return FILEID_INVALID; | |
1370 | } else if (len < 2) { | |
1371 | *max_len = 2; | |
1372 | return FILEID_INVALID; | |
1373 | } | |
1374 | ||
1375 | len = 2; | |
1376 | fid->i32.ino = inode->i_ino; | |
1377 | fid->i32.gen = inode->i_generation; | |
1378 | if (parent) { | |
1379 | fid->i32.parent_ino = parent->i_ino; | |
1380 | fid->i32.parent_gen = parent->i_generation; | |
1381 | len = 4; | |
1382 | type = FILEID_INO32_GEN_PARENT; | |
1383 | } | |
1384 | *max_len = len; | |
1385 | return type; | |
1386 | } | |
1387 | EXPORT_SYMBOL_GPL(generic_encode_ino32_fh); | |
1388 | ||
2596110a CH |
1389 | /** |
1390 | * generic_fh_to_dentry - generic helper for the fh_to_dentry export operation | |
1391 | * @sb: filesystem to do the file handle conversion on | |
1392 | * @fid: file handle to convert | |
1393 | * @fh_len: length of the file handle in bytes | |
1394 | * @fh_type: type of file handle | |
1395 | * @get_inode: filesystem callback to retrieve inode | |
1396 | * | |
1397 | * This function decodes @fid as long as it has one of the well-known | |
1398 | * Linux filehandle types and calls @get_inode on it to retrieve the | |
1399 | * inode for the object specified in the file handle. | |
1400 | */ | |
1401 | struct dentry *generic_fh_to_dentry(struct super_block *sb, struct fid *fid, | |
1402 | int fh_len, int fh_type, struct inode *(*get_inode) | |
1403 | (struct super_block *sb, u64 ino, u32 gen)) | |
1404 | { | |
1405 | struct inode *inode = NULL; | |
1406 | ||
1407 | if (fh_len < 2) | |
1408 | return NULL; | |
1409 | ||
1410 | switch (fh_type) { | |
1411 | case FILEID_INO32_GEN: | |
1412 | case FILEID_INO32_GEN_PARENT: | |
1413 | inode = get_inode(sb, fid->i32.ino, fid->i32.gen); | |
1414 | break; | |
1415 | } | |
1416 | ||
4ea3ada2 | 1417 | return d_obtain_alias(inode); |
2596110a CH |
1418 | } |
1419 | EXPORT_SYMBOL_GPL(generic_fh_to_dentry); | |
1420 | ||
1421 | /** | |
ca186830 | 1422 | * generic_fh_to_parent - generic helper for the fh_to_parent export operation |
2596110a CH |
1423 | * @sb: filesystem to do the file handle conversion on |
1424 | * @fid: file handle to convert | |
1425 | * @fh_len: length of the file handle in bytes | |
1426 | * @fh_type: type of file handle | |
1427 | * @get_inode: filesystem callback to retrieve inode | |
1428 | * | |
1429 | * This function decodes @fid as long as it has one of the well-known | |
1430 | * Linux filehandle types and calls @get_inode on it to retrieve the | |
1431 | * inode for the _parent_ object specified in the file handle if it | |
1432 | * is specified in the file handle, or NULL otherwise. | |
1433 | */ | |
1434 | struct dentry *generic_fh_to_parent(struct super_block *sb, struct fid *fid, | |
1435 | int fh_len, int fh_type, struct inode *(*get_inode) | |
1436 | (struct super_block *sb, u64 ino, u32 gen)) | |
1437 | { | |
1438 | struct inode *inode = NULL; | |
1439 | ||
1440 | if (fh_len <= 2) | |
1441 | return NULL; | |
1442 | ||
1443 | switch (fh_type) { | |
1444 | case FILEID_INO32_GEN_PARENT: | |
1445 | inode = get_inode(sb, fid->i32.parent_ino, | |
1446 | (fh_len > 3 ? fid->i32.parent_gen : 0)); | |
1447 | break; | |
1448 | } | |
1449 | ||
4ea3ada2 | 1450 | return d_obtain_alias(inode); |
2596110a CH |
1451 | } |
1452 | EXPORT_SYMBOL_GPL(generic_fh_to_parent); | |
1453 | ||
1b061d92 | 1454 | /** |
ac13a829 FF |
1455 | * __generic_file_fsync - generic fsync implementation for simple filesystems |
1456 | * | |
1b061d92 | 1457 | * @file: file to synchronize |
ac13a829 FF |
1458 | * @start: start offset in bytes |
1459 | * @end: end offset in bytes (inclusive) | |
1b061d92 CH |
1460 | * @datasync: only synchronize essential metadata if true |
1461 | * | |
1462 | * This is a generic implementation of the fsync method for simple | |
1463 | * filesystems which track all non-inode metadata in the buffers list | |
1464 | * hanging off the address_space structure. | |
1465 | */ | |
ac13a829 FF |
1466 | int __generic_file_fsync(struct file *file, loff_t start, loff_t end, |
1467 | int datasync) | |
d5aacad5 | 1468 | { |
7ea80859 | 1469 | struct inode *inode = file->f_mapping->host; |
d5aacad5 AV |
1470 | int err; |
1471 | int ret; | |
1472 | ||
383aa543 | 1473 | err = file_write_and_wait_range(file, start, end); |
02c24a82 JB |
1474 | if (err) |
1475 | return err; | |
1476 | ||
5955102c | 1477 | inode_lock(inode); |
d5aacad5 | 1478 | ret = sync_mapping_buffers(inode->i_mapping); |
0ae45f63 | 1479 | if (!(inode->i_state & I_DIRTY_ALL)) |
02c24a82 | 1480 | goto out; |
d5aacad5 | 1481 | if (datasync && !(inode->i_state & I_DIRTY_DATASYNC)) |
02c24a82 | 1482 | goto out; |
d5aacad5 | 1483 | |
c3765016 | 1484 | err = sync_inode_metadata(inode, 1); |
d5aacad5 AV |
1485 | if (ret == 0) |
1486 | ret = err; | |
ac13a829 | 1487 | |
02c24a82 | 1488 | out: |
5955102c | 1489 | inode_unlock(inode); |
383aa543 JL |
1490 | /* check and advance again to catch errors after syncing out buffers */ |
1491 | err = file_check_and_advance_wb_err(file); | |
1492 | if (ret == 0) | |
1493 | ret = err; | |
1494 | return ret; | |
d5aacad5 | 1495 | } |
ac13a829 FF |
1496 | EXPORT_SYMBOL(__generic_file_fsync); |
1497 | ||
1498 | /** | |
1499 | * generic_file_fsync - generic fsync implementation for simple filesystems | |
1500 | * with flush | |
1501 | * @file: file to synchronize | |
1502 | * @start: start offset in bytes | |
1503 | * @end: end offset in bytes (inclusive) | |
1504 | * @datasync: only synchronize essential metadata if true | |
1505 | * | |
1506 | */ | |
1507 | ||
1508 | int generic_file_fsync(struct file *file, loff_t start, loff_t end, | |
1509 | int datasync) | |
1510 | { | |
1511 | struct inode *inode = file->f_mapping->host; | |
1512 | int err; | |
1513 | ||
1514 | err = __generic_file_fsync(file, start, end, datasync); | |
1515 | if (err) | |
1516 | return err; | |
c6bf3f0e | 1517 | return blkdev_issue_flush(inode->i_sb->s_bdev); |
ac13a829 | 1518 | } |
1b061d92 CH |
1519 | EXPORT_SYMBOL(generic_file_fsync); |
1520 | ||
30ca22c7 PL |
1521 | /** |
1522 | * generic_check_addressable - Check addressability of file system | |
1523 | * @blocksize_bits: log of file system block size | |
1524 | * @num_blocks: number of blocks in file system | |
1525 | * | |
1526 | * Determine whether a file system with @num_blocks blocks (and a | |
1527 | * block size of 2**@blocksize_bits) is addressable by the sector_t | |
1528 | * and page cache of the system. Return 0 if so and -EFBIG otherwise. | |
1529 | */ | |
1530 | int generic_check_addressable(unsigned blocksize_bits, u64 num_blocks) | |
1531 | { | |
1532 | u64 last_fs_block = num_blocks - 1; | |
a33f13ef | 1533 | u64 last_fs_page = |
09cbfeaf | 1534 | last_fs_block >> (PAGE_SHIFT - blocksize_bits); |
30ca22c7 PL |
1535 | |
1536 | if (unlikely(num_blocks == 0)) | |
1537 | return 0; | |
1538 | ||
09cbfeaf | 1539 | if ((blocksize_bits < 9) || (blocksize_bits > PAGE_SHIFT)) |
30ca22c7 PL |
1540 | return -EINVAL; |
1541 | ||
a33f13ef JB |
1542 | if ((last_fs_block > (sector_t)(~0ULL) >> (blocksize_bits - 9)) || |
1543 | (last_fs_page > (pgoff_t)(~0ULL))) { | |
30ca22c7 PL |
1544 | return -EFBIG; |
1545 | } | |
1546 | return 0; | |
1547 | } | |
1548 | EXPORT_SYMBOL(generic_check_addressable); | |
1549 | ||
1b061d92 CH |
1550 | /* |
1551 | * No-op implementation of ->fsync for in-memory filesystems. | |
1552 | */ | |
02c24a82 | 1553 | int noop_fsync(struct file *file, loff_t start, loff_t end, int datasync) |
1b061d92 CH |
1554 | { |
1555 | return 0; | |
1556 | } | |
1b061d92 | 1557 | EXPORT_SYMBOL(noop_fsync); |
87dc800b | 1558 | |
f44c7763 DW |
1559 | ssize_t noop_direct_IO(struct kiocb *iocb, struct iov_iter *iter) |
1560 | { | |
1561 | /* | |
1562 | * iomap based filesystems support direct I/O without need for | |
1563 | * this callback. However, it still needs to be set in | |
1564 | * inode->a_ops so that open/fcntl know that direct I/O is | |
1565 | * generally supported. | |
1566 | */ | |
1567 | return -EINVAL; | |
1568 | } | |
1569 | EXPORT_SYMBOL_GPL(noop_direct_IO); | |
1570 | ||
fceef393 AV |
1571 | /* Because kfree isn't assignment-compatible with void(void*) ;-/ */ |
1572 | void kfree_link(void *p) | |
87dc800b | 1573 | { |
fceef393 | 1574 | kfree(p); |
87dc800b | 1575 | } |
fceef393 | 1576 | EXPORT_SYMBOL(kfree_link); |
6987843f | 1577 | |
6987843f AV |
1578 | struct inode *alloc_anon_inode(struct super_block *s) |
1579 | { | |
1580 | static const struct address_space_operations anon_aops = { | |
46de8b97 | 1581 | .dirty_folio = noop_dirty_folio, |
6987843f AV |
1582 | }; |
1583 | struct inode *inode = new_inode_pseudo(s); | |
1584 | ||
1585 | if (!inode) | |
1586 | return ERR_PTR(-ENOMEM); | |
1587 | ||
1588 | inode->i_ino = get_next_ino(); | |
1589 | inode->i_mapping->a_ops = &anon_aops; | |
1590 | ||
1591 | /* | |
1592 | * Mark the inode dirty from the very beginning, | |
1593 | * that way it will never be moved to the dirty | |
1594 | * list because mark_inode_dirty() will think | |
1595 | * that it already _is_ on the dirty list. | |
1596 | */ | |
1597 | inode->i_state = I_DIRTY; | |
1598 | inode->i_mode = S_IRUSR | S_IWUSR; | |
1599 | inode->i_uid = current_fsuid(); | |
1600 | inode->i_gid = current_fsgid(); | |
1601 | inode->i_flags |= S_PRIVATE; | |
077c212f | 1602 | simple_inode_init_ts(inode); |
6987843f AV |
1603 | return inode; |
1604 | } | |
1605 | EXPORT_SYMBOL(alloc_anon_inode); | |
1c994a09 JL |
1606 | |
1607 | /** | |
1608 | * simple_nosetlease - generic helper for prohibiting leases | |
1609 | * @filp: file pointer | |
1610 | * @arg: type of lease to obtain | |
1611 | * @flp: new lease supplied for insertion | |
e6f5c789 | 1612 | * @priv: private data for lm_setup operation |
1c994a09 JL |
1613 | * |
1614 | * Generic helper for filesystems that do not wish to allow leases to be set. | |
1615 | * All arguments are ignored and it just returns -EINVAL. | |
1616 | */ | |
1617 | int | |
c69ff407 | 1618 | simple_nosetlease(struct file *filp, int arg, struct file_lease **flp, |
e6f5c789 | 1619 | void **priv) |
1c994a09 JL |
1620 | { |
1621 | return -EINVAL; | |
1622 | } | |
1623 | EXPORT_SYMBOL(simple_nosetlease); | |
61ba64fc | 1624 | |
6ee9706a EB |
1625 | /** |
1626 | * simple_get_link - generic helper to get the target of "fast" symlinks | |
1627 | * @dentry: not used here | |
1628 | * @inode: the symlink inode | |
1629 | * @done: not used here | |
1630 | * | |
1631 | * Generic helper for filesystems to use for symlink inodes where a pointer to | |
1632 | * the symlink target is stored in ->i_link. NOTE: this isn't normally called, | |
1633 | * since as an optimization the path lookup code uses any non-NULL ->i_link | |
1634 | * directly, without calling ->get_link(). But ->get_link() still must be set, | |
1635 | * to mark the inode_operations as being for a symlink. | |
1636 | * | |
1637 | * Return: the symlink target | |
1638 | */ | |
6b255391 | 1639 | const char *simple_get_link(struct dentry *dentry, struct inode *inode, |
fceef393 | 1640 | struct delayed_call *done) |
61ba64fc | 1641 | { |
6b255391 | 1642 | return inode->i_link; |
61ba64fc | 1643 | } |
6b255391 | 1644 | EXPORT_SYMBOL(simple_get_link); |
61ba64fc AV |
1645 | |
1646 | const struct inode_operations simple_symlink_inode_operations = { | |
6b255391 | 1647 | .get_link = simple_get_link, |
61ba64fc AV |
1648 | }; |
1649 | EXPORT_SYMBOL(simple_symlink_inode_operations); | |
fbabfd0f EB |
1650 | |
1651 | /* | |
1652 | * Operations for a permanently empty directory. | |
1653 | */ | |
1654 | static struct dentry *empty_dir_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags) | |
1655 | { | |
1656 | return ERR_PTR(-ENOENT); | |
1657 | } | |
1658 | ||
b74d24f7 | 1659 | static int empty_dir_getattr(struct mnt_idmap *idmap, |
549c7297 | 1660 | const struct path *path, struct kstat *stat, |
a528d35e | 1661 | u32 request_mask, unsigned int query_flags) |
fbabfd0f | 1662 | { |
a528d35e | 1663 | struct inode *inode = d_inode(path->dentry); |
0d72b928 | 1664 | generic_fillattr(&nop_mnt_idmap, request_mask, inode, stat); |
fbabfd0f EB |
1665 | return 0; |
1666 | } | |
1667 | ||
c1632a0f | 1668 | static int empty_dir_setattr(struct mnt_idmap *idmap, |
549c7297 | 1669 | struct dentry *dentry, struct iattr *attr) |
fbabfd0f EB |
1670 | { |
1671 | return -EPERM; | |
1672 | } | |
1673 | ||
fbabfd0f EB |
1674 | static ssize_t empty_dir_listxattr(struct dentry *dentry, char *list, size_t size) |
1675 | { | |
1676 | return -EOPNOTSUPP; | |
1677 | } | |
1678 | ||
1679 | static const struct inode_operations empty_dir_inode_operations = { | |
1680 | .lookup = empty_dir_lookup, | |
1681 | .permission = generic_permission, | |
1682 | .setattr = empty_dir_setattr, | |
1683 | .getattr = empty_dir_getattr, | |
fbabfd0f EB |
1684 | .listxattr = empty_dir_listxattr, |
1685 | }; | |
1686 | ||
1687 | static loff_t empty_dir_llseek(struct file *file, loff_t offset, int whence) | |
1688 | { | |
1689 | /* An empty directory has two entries . and .. at offsets 0 and 1 */ | |
1690 | return generic_file_llseek_size(file, offset, whence, 2, 2); | |
1691 | } | |
1692 | ||
1693 | static int empty_dir_readdir(struct file *file, struct dir_context *ctx) | |
1694 | { | |
1695 | dir_emit_dots(file, ctx); | |
1696 | return 0; | |
1697 | } | |
1698 | ||
1699 | static const struct file_operations empty_dir_operations = { | |
1700 | .llseek = empty_dir_llseek, | |
1701 | .read = generic_read_dir, | |
c51da20c | 1702 | .iterate_shared = empty_dir_readdir, |
fbabfd0f EB |
1703 | .fsync = noop_fsync, |
1704 | }; | |
1705 | ||
1706 | ||
1707 | void make_empty_dir_inode(struct inode *inode) | |
1708 | { | |
1709 | set_nlink(inode, 2); | |
1710 | inode->i_mode = S_IFDIR | S_IRUGO | S_IXUGO; | |
1711 | inode->i_uid = GLOBAL_ROOT_UID; | |
1712 | inode->i_gid = GLOBAL_ROOT_GID; | |
1713 | inode->i_rdev = 0; | |
4b75de86 | 1714 | inode->i_size = 0; |
fbabfd0f EB |
1715 | inode->i_blkbits = PAGE_SHIFT; |
1716 | inode->i_blocks = 0; | |
1717 | ||
1718 | inode->i_op = &empty_dir_inode_operations; | |
f5c24438 | 1719 | inode->i_opflags &= ~IOP_XATTR; |
fbabfd0f EB |
1720 | inode->i_fop = &empty_dir_operations; |
1721 | } | |
1722 | ||
1723 | bool is_empty_dir_inode(struct inode *inode) | |
1724 | { | |
1725 | return (inode->i_fop == &empty_dir_operations) && | |
1726 | (inode->i_op == &empty_dir_inode_operations); | |
1727 | } | |
c843843e | 1728 | |
5298d4bf | 1729 | #if IS_ENABLED(CONFIG_UNICODE) |
c843843e DR |
1730 | /** |
1731 | * generic_ci_d_compare - generic d_compare implementation for casefolding filesystems | |
1732 | * @dentry: dentry whose name we are checking against | |
1733 | * @len: len of name of dentry | |
1734 | * @str: str pointer to name of dentry | |
1735 | * @name: Name to compare against | |
1736 | * | |
1737 | * Return: 0 if names match, 1 if mismatch, or -ERRNO | |
1738 | */ | |
794c43f7 EB |
1739 | static int generic_ci_d_compare(const struct dentry *dentry, unsigned int len, |
1740 | const char *str, const struct qstr *name) | |
c843843e | 1741 | { |
0906fbb2 GKB |
1742 | const struct dentry *parent; |
1743 | const struct inode *dir; | |
c843843e | 1744 | char strbuf[DNAME_INLINE_LEN]; |
0906fbb2 GKB |
1745 | struct qstr qstr; |
1746 | ||
1747 | /* | |
1748 | * Attempt a case-sensitive match first. It is cheaper and | |
1749 | * should cover most lookups, including all the sane | |
1750 | * applications that expect a case-sensitive filesystem. | |
1751 | * | |
1752 | * This comparison is safe under RCU because the caller | |
1753 | * guarantees the consistency between str and len. See | |
1754 | * __d_lookup_rcu_op_compare() for details. | |
1755 | */ | |
1756 | if (len == name->len && !memcmp(str, name->name, len)) | |
1757 | return 0; | |
c843843e | 1758 | |
0906fbb2 GKB |
1759 | parent = READ_ONCE(dentry->d_parent); |
1760 | dir = READ_ONCE(parent->d_inode); | |
af494af3 | 1761 | if (!dir || !IS_CASEFOLDED(dir)) |
0906fbb2 GKB |
1762 | return 1; |
1763 | ||
c843843e DR |
1764 | /* |
1765 | * If the dentry name is stored in-line, then it may be concurrently | |
1766 | * modified by a rename. If this happens, the VFS will eventually retry | |
1767 | * the lookup, so it doesn't matter what ->d_compare() returns. | |
1768 | * However, it's unsafe to call utf8_strncasecmp() with an unstable | |
1769 | * string. Therefore, we have to copy the name into a temporary buffer. | |
1770 | */ | |
1771 | if (len <= DNAME_INLINE_LEN - 1) { | |
1772 | memcpy(strbuf, str, len); | |
1773 | strbuf[len] = 0; | |
0906fbb2 | 1774 | str = strbuf; |
c843843e DR |
1775 | /* prevent compiler from optimizing out the temporary buffer */ |
1776 | barrier(); | |
1777 | } | |
0906fbb2 GKB |
1778 | qstr.len = len; |
1779 | qstr.name = str; | |
c843843e | 1780 | |
0906fbb2 | 1781 | return utf8_strncasecmp(dentry->d_sb->s_encoding, name, &qstr); |
c843843e | 1782 | } |
c843843e DR |
1783 | |
1784 | /** | |
1785 | * generic_ci_d_hash - generic d_hash implementation for casefolding filesystems | |
1786 | * @dentry: dentry of the parent directory | |
1787 | * @str: qstr of name whose hash we should fill in | |
1788 | * | |
1789 | * Return: 0 if hash was successful or unchanged, and -EINVAL on error | |
1790 | */ | |
794c43f7 | 1791 | static int generic_ci_d_hash(const struct dentry *dentry, struct qstr *str) |
c843843e DR |
1792 | { |
1793 | const struct inode *dir = READ_ONCE(dentry->d_inode); | |
1794 | struct super_block *sb = dentry->d_sb; | |
1795 | const struct unicode_map *um = sb->s_encoding; | |
bae8bc46 | 1796 | int ret; |
c843843e | 1797 | |
af494af3 | 1798 | if (!dir || !IS_CASEFOLDED(dir)) |
c843843e DR |
1799 | return 0; |
1800 | ||
1801 | ret = utf8_casefold_hash(um, dentry, str); | |
1802 | if (ret < 0 && sb_has_strict_encoding(sb)) | |
1803 | return -EINVAL; | |
1804 | return 0; | |
1805 | } | |
608af703 DR |
1806 | |
1807 | static const struct dentry_operations generic_ci_dentry_ops = { | |
1808 | .d_hash = generic_ci_d_hash, | |
1809 | .d_compare = generic_ci_d_compare, | |
608af703 | 1810 | #ifdef CONFIG_FS_ENCRYPTION |
608af703 | 1811 | .d_revalidate = fscrypt_d_revalidate, |
e6ca2883 | 1812 | #endif |
608af703 DR |
1813 | }; |
1814 | #endif | |
1815 | ||
e6ca2883 GKB |
1816 | #ifdef CONFIG_FS_ENCRYPTION |
1817 | static const struct dentry_operations generic_encrypted_dentry_ops = { | |
608af703 DR |
1818 | .d_revalidate = fscrypt_d_revalidate, |
1819 | }; | |
1820 | #endif | |
1821 | ||
1822 | /** | |
70dfe3f0 GKB |
1823 | * generic_set_sb_d_ops - helper for choosing the set of |
1824 | * filesystem-wide dentry operations for the enabled features | |
1825 | * @sb: superblock to be configured | |
608af703 | 1826 | * |
70dfe3f0 GKB |
1827 | * Filesystems supporting casefolding and/or fscrypt can call this |
1828 | * helper at mount-time to configure sb->s_d_op to best set of dentry | |
1829 | * operations required for the enabled features. The helper must be | |
1830 | * called after these have been configured, but before the root dentry | |
1831 | * is created. | |
608af703 | 1832 | */ |
70dfe3f0 | 1833 | void generic_set_sb_d_ops(struct super_block *sb) |
608af703 | 1834 | { |
5298d4bf | 1835 | #if IS_ENABLED(CONFIG_UNICODE) |
70dfe3f0 GKB |
1836 | if (sb->s_encoding) { |
1837 | sb->s_d_op = &generic_ci_dentry_ops; | |
608af703 DR |
1838 | return; |
1839 | } | |
c843843e | 1840 | #endif |
608af703 | 1841 | #ifdef CONFIG_FS_ENCRYPTION |
70dfe3f0 GKB |
1842 | if (sb->s_cop) { |
1843 | sb->s_d_op = &generic_encrypted_dentry_ops; | |
608af703 DR |
1844 | return; |
1845 | } | |
1846 | #endif | |
1847 | } | |
70dfe3f0 | 1848 | EXPORT_SYMBOL(generic_set_sb_d_ops); |
5ca14835 AM |
1849 | |
1850 | /** | |
1851 | * inode_maybe_inc_iversion - increments i_version | |
1852 | * @inode: inode with the i_version that should be updated | |
1853 | * @force: increment the counter even if it's not necessary? | |
1854 | * | |
1855 | * Every time the inode is modified, the i_version field must be seen to have | |
1856 | * changed by any observer. | |
1857 | * | |
1858 | * If "force" is set or the QUERIED flag is set, then ensure that we increment | |
1859 | * the value, and clear the queried flag. | |
1860 | * | |
1861 | * In the common case where neither is set, then we can return "false" without | |
1862 | * updating i_version. | |
1863 | * | |
1864 | * If this function returns false, and no other metadata has changed, then we | |
1865 | * can avoid logging the metadata. | |
1866 | */ | |
1867 | bool inode_maybe_inc_iversion(struct inode *inode, bool force) | |
1868 | { | |
1869 | u64 cur, new; | |
1870 | ||
1871 | /* | |
1872 | * The i_version field is not strictly ordered with any other inode | |
1873 | * information, but the legacy inode_inc_iversion code used a spinlock | |
1874 | * to serialize increments. | |
1875 | * | |
1876 | * Here, we add full memory barriers to ensure that any de-facto | |
1877 | * ordering with other info is preserved. | |
1878 | * | |
1879 | * This barrier pairs with the barrier in inode_query_iversion() | |
1880 | */ | |
1881 | smp_mb(); | |
1882 | cur = inode_peek_iversion_raw(inode); | |
1883 | do { | |
1884 | /* If flag is clear then we needn't do anything */ | |
1885 | if (!force && !(cur & I_VERSION_QUERIED)) | |
1886 | return false; | |
1887 | ||
1888 | /* Since lowest bit is flag, add 2 to avoid it */ | |
1889 | new = (cur & ~I_VERSION_QUERIED) + I_VERSION_INCREMENT; | |
1890 | } while (!atomic64_try_cmpxchg(&inode->i_version, &cur, new)); | |
1891 | return true; | |
1892 | } | |
1893 | EXPORT_SYMBOL(inode_maybe_inc_iversion); | |
c5bc1b3f JL |
1894 | |
1895 | /** | |
1896 | * inode_query_iversion - read i_version for later use | |
1897 | * @inode: inode from which i_version should be read | |
1898 | * | |
1899 | * Read the inode i_version counter. This should be used by callers that wish | |
1900 | * to store the returned i_version for later comparison. This will guarantee | |
1901 | * that a later query of the i_version will result in a different value if | |
1902 | * anything has changed. | |
1903 | * | |
1904 | * In this implementation, we fetch the current value, set the QUERIED flag and | |
1905 | * then try to swap it into place with a cmpxchg, if it wasn't already set. If | |
1906 | * that fails, we try again with the newly fetched value from the cmpxchg. | |
1907 | */ | |
1908 | u64 inode_query_iversion(struct inode *inode) | |
1909 | { | |
1910 | u64 cur, new; | |
1911 | ||
1912 | cur = inode_peek_iversion_raw(inode); | |
1913 | do { | |
1914 | /* If flag is already set, then no need to swap */ | |
1915 | if (cur & I_VERSION_QUERIED) { | |
1916 | /* | |
1917 | * This barrier (and the implicit barrier in the | |
1918 | * cmpxchg below) pairs with the barrier in | |
1919 | * inode_maybe_inc_iversion(). | |
1920 | */ | |
1921 | smp_mb(); | |
1922 | break; | |
1923 | } | |
1924 | ||
1925 | new = cur | I_VERSION_QUERIED; | |
1926 | } while (!atomic64_try_cmpxchg(&inode->i_version, &cur, new)); | |
1927 | return cur >> I_VERSION_QUERIED_SHIFT; | |
1928 | } | |
1929 | EXPORT_SYMBOL(inode_query_iversion); | |
44fff0fa CH |
1930 | |
1931 | ssize_t direct_write_fallback(struct kiocb *iocb, struct iov_iter *iter, | |
1932 | ssize_t direct_written, ssize_t buffered_written) | |
1933 | { | |
1934 | struct address_space *mapping = iocb->ki_filp->f_mapping; | |
1935 | loff_t pos = iocb->ki_pos - buffered_written; | |
1936 | loff_t end = iocb->ki_pos - 1; | |
1937 | int err; | |
1938 | ||
1939 | /* | |
1940 | * If the buffered write fallback returned an error, we want to return | |
1941 | * the number of bytes which were written by direct I/O, or the error | |
1942 | * code if that was zero. | |
1943 | * | |
1944 | * Note that this differs from normal direct-io semantics, which will | |
1945 | * return -EFOO even if some bytes were written. | |
1946 | */ | |
1947 | if (unlikely(buffered_written < 0)) { | |
1948 | if (direct_written) | |
1949 | return direct_written; | |
1950 | return buffered_written; | |
1951 | } | |
1952 | ||
1953 | /* | |
1954 | * We need to ensure that the page cache pages are written to disk and | |
1955 | * invalidated to preserve the expected O_DIRECT semantics. | |
1956 | */ | |
1957 | err = filemap_write_and_wait_range(mapping, pos, end); | |
1958 | if (err < 0) { | |
1959 | /* | |
1960 | * We don't know how much we wrote, so just return the number of | |
1961 | * bytes which were direct-written | |
1962 | */ | |
8287474a | 1963 | iocb->ki_pos -= buffered_written; |
44fff0fa CH |
1964 | if (direct_written) |
1965 | return direct_written; | |
1966 | return err; | |
1967 | } | |
1968 | invalidate_mapping_pages(mapping, pos >> PAGE_SHIFT, end >> PAGE_SHIFT); | |
1969 | return direct_written + buffered_written; | |
1970 | } | |
1971 | EXPORT_SYMBOL_GPL(direct_write_fallback); | |
077c212f JL |
1972 | |
1973 | /** | |
1974 | * simple_inode_init_ts - initialize the timestamps for a new inode | |
1975 | * @inode: inode to be initialized | |
1976 | * | |
1977 | * When a new inode is created, most filesystems set the timestamps to the | |
1978 | * current time. Add a helper to do this. | |
1979 | */ | |
1980 | struct timespec64 simple_inode_init_ts(struct inode *inode) | |
1981 | { | |
1982 | struct timespec64 ts = inode_set_ctime_current(inode); | |
1983 | ||
1984 | inode_set_atime_to_ts(inode, ts); | |
1985 | inode_set_mtime_to_ts(inode, ts); | |
1986 | return ts; | |
1987 | } | |
1988 | EXPORT_SYMBOL(simple_inode_init_ts); | |
07fd7c32 CB |
1989 | |
1990 | static inline struct dentry *get_stashed_dentry(struct dentry *stashed) | |
1991 | { | |
1992 | struct dentry *dentry; | |
1993 | ||
1994 | guard(rcu)(); | |
1995 | dentry = READ_ONCE(stashed); | |
1996 | if (!dentry) | |
1997 | return NULL; | |
1998 | if (!lockref_get_not_dead(&dentry->d_lockref)) | |
1999 | return NULL; | |
2000 | return dentry; | |
2001 | } | |
2002 | ||
2558e3b2 | 2003 | static struct dentry *prepare_anon_dentry(struct dentry **stashed, |
159a0d9f | 2004 | struct super_block *sb, |
159a0d9f | 2005 | void *data) |
07fd7c32 CB |
2006 | { |
2007 | struct dentry *dentry; | |
2008 | struct inode *inode; | |
e9c5263c | 2009 | const struct stashed_operations *sops = sb->s_fs_info; |
9d9539db | 2010 | int ret; |
07fd7c32 CB |
2011 | |
2012 | inode = new_inode_pseudo(sb); | |
2013 | if (!inode) { | |
9d9539db | 2014 | sops->put_data(data); |
07fd7c32 CB |
2015 | return ERR_PTR(-ENOMEM); |
2016 | } | |
2017 | ||
07fd7c32 | 2018 | inode->i_flags |= S_IMMUTABLE; |
e9c5263c | 2019 | inode->i_mode = S_IFREG; |
07fd7c32 | 2020 | simple_inode_init_ts(inode); |
9d9539db CB |
2021 | |
2022 | ret = sops->init_inode(inode, data); | |
2023 | if (ret < 0) { | |
2024 | iput(inode); | |
2025 | return ERR_PTR(ret); | |
2026 | } | |
e9c5263c CB |
2027 | |
2028 | /* Notice when this is changed. */ | |
2029 | WARN_ON_ONCE(!S_ISREG(inode->i_mode)); | |
2030 | WARN_ON_ONCE(!IS_IMMUTABLE(inode)); | |
07fd7c32 | 2031 | |
9d9539db CB |
2032 | dentry = d_alloc_anon(sb); |
2033 | if (!dentry) { | |
2034 | iput(inode); | |
2035 | return ERR_PTR(-ENOMEM); | |
2036 | } | |
2037 | ||
2558e3b2 CB |
2038 | /* Store address of location where dentry's supposed to be stashed. */ |
2039 | dentry->d_fsdata = stashed; | |
2040 | ||
07fd7c32 CB |
2041 | /* @data is now owned by the fs */ |
2042 | d_instantiate(dentry, inode); | |
159a0d9f CB |
2043 | return dentry; |
2044 | } | |
07fd7c32 | 2045 | |
159a0d9f CB |
2046 | static struct dentry *stash_dentry(struct dentry **stashed, |
2047 | struct dentry *dentry) | |
2048 | { | |
2049 | guard(rcu)(); | |
2050 | for (;;) { | |
2051 | struct dentry *old; | |
07fd7c32 | 2052 | |
159a0d9f CB |
2053 | /* Assume any old dentry was cleared out. */ |
2054 | old = cmpxchg(stashed, NULL, dentry); | |
2055 | if (likely(!old)) | |
2056 | return dentry; | |
2057 | ||
2058 | /* Check if somebody else installed a reusable dentry. */ | |
2059 | if (lockref_get_not_dead(&old->d_lockref)) | |
2060 | return old; | |
2061 | ||
2062 | /* There's an old dead dentry there, try to take it over. */ | |
2063 | if (likely(try_cmpxchg(stashed, &old, dentry))) | |
2064 | return dentry; | |
2065 | } | |
07fd7c32 CB |
2066 | } |
2067 | ||
2068 | /** | |
2069 | * path_from_stashed - create path from stashed or new dentry | |
2070 | * @stashed: where to retrieve or stash dentry | |
07fd7c32 | 2071 | * @mnt: mnt of the filesystems to use |
07fd7c32 CB |
2072 | * @data: data to store in inode->i_private |
2073 | * @path: path to create | |
2074 | * | |
2075 | * The function tries to retrieve a stashed dentry from @stashed. If the dentry | |
2076 | * is still valid then it will be reused. If the dentry isn't able the function | |
159a0d9f CB |
2077 | * will allocate a new dentry and inode. It will then check again whether it |
2078 | * can reuse an existing dentry in case one has been added in the meantime or | |
2079 | * update @stashed with the newly added dentry. | |
07fd7c32 CB |
2080 | * |
2081 | * Special-purpose helper for nsfs and pidfs. | |
2082 | * | |
e9c5263c | 2083 | * Return: On success zero and on failure a negative error is returned. |
07fd7c32 | 2084 | */ |
9d9539db CB |
2085 | int path_from_stashed(struct dentry **stashed, struct vfsmount *mnt, void *data, |
2086 | struct path *path) | |
07fd7c32 CB |
2087 | { |
2088 | struct dentry *dentry; | |
e9c5263c | 2089 | const struct stashed_operations *sops = mnt->mnt_sb->s_fs_info; |
07fd7c32 | 2090 | |
159a0d9f CB |
2091 | /* See if dentry can be reused. */ |
2092 | path->dentry = get_stashed_dentry(*stashed); | |
e9c5263c CB |
2093 | if (path->dentry) { |
2094 | sops->put_data(data); | |
07fd7c32 | 2095 | goto out_path; |
e9c5263c | 2096 | } |
07fd7c32 | 2097 | |
159a0d9f | 2098 | /* Allocate a new dentry. */ |
9d9539db CB |
2099 | dentry = prepare_anon_dentry(stashed, mnt->mnt_sb, data); |
2100 | if (IS_ERR(dentry)) | |
07fd7c32 | 2101 | return PTR_ERR(dentry); |
159a0d9f CB |
2102 | |
2103 | /* Added a new dentry. @data is now owned by the filesystem. */ | |
2104 | path->dentry = stash_dentry(stashed, dentry); | |
2105 | if (path->dentry != dentry) | |
2106 | dput(dentry); | |
07fd7c32 CB |
2107 | |
2108 | out_path: | |
2558e3b2 CB |
2109 | WARN_ON_ONCE(path->dentry->d_fsdata != stashed); |
2110 | WARN_ON_ONCE(d_inode(path->dentry)->i_private != data); | |
07fd7c32 | 2111 | path->mnt = mntget(mnt); |
e9c5263c | 2112 | return 0; |
07fd7c32 | 2113 | } |
2558e3b2 CB |
2114 | |
2115 | void stashed_dentry_prune(struct dentry *dentry) | |
2116 | { | |
2117 | struct dentry **stashed = dentry->d_fsdata; | |
2118 | struct inode *inode = d_inode(dentry); | |
2119 | ||
2120 | if (WARN_ON_ONCE(!stashed)) | |
2121 | return; | |
2122 | ||
2123 | if (!inode) | |
2124 | return; | |
2125 | ||
2126 | /* | |
2127 | * Only replace our own @dentry as someone else might've | |
2128 | * already cleared out @dentry and stashed their own | |
2129 | * dentry in there. | |
2130 | */ | |
2131 | cmpxchg(stashed, dentry, NULL); | |
2132 | } |