Commit | Line | Data |
---|---|---|
d123d8e1 MS |
1 | /* |
2 | FUSE: Filesystem in Userspace | |
3 | Copyright (C) 2001-2018 Miklos Szeredi <miklos@szeredi.hu> | |
4 | ||
5 | This program can be distributed under the terms of the GNU GPL. | |
6 | See the file COPYING. | |
7 | */ | |
8 | ||
9 | ||
10 | #include "fuse_i.h" | |
261aaba7 | 11 | #include <linux/iversion.h> |
d123d8e1 | 12 | #include <linux/posix_acl.h> |
69e34551 MS |
13 | #include <linux/pagemap.h> |
14 | #include <linux/highmem.h> | |
d123d8e1 MS |
15 | |
16 | static bool fuse_use_readdirplus(struct inode *dir, struct dir_context *ctx) | |
17 | { | |
18 | struct fuse_conn *fc = get_fuse_conn(dir); | |
19 | struct fuse_inode *fi = get_fuse_inode(dir); | |
20 | ||
21 | if (!fc->do_readdirplus) | |
22 | return false; | |
23 | if (!fc->readdirplus_auto) | |
24 | return true; | |
25 | if (test_and_clear_bit(FUSE_I_ADVISE_RDPLUS, &fi->state)) | |
26 | return true; | |
27 | if (ctx->pos == 0) | |
28 | return true; | |
29 | return false; | |
30 | } | |
31 | ||
69e34551 MS |
32 | static void fuse_add_dirent_to_cache(struct file *file, |
33 | struct fuse_dirent *dirent, loff_t pos) | |
34 | { | |
35 | struct fuse_inode *fi = get_fuse_inode(file_inode(file)); | |
36 | size_t reclen = FUSE_DIRENT_SIZE(dirent); | |
37 | pgoff_t index; | |
38 | struct page *page; | |
39 | loff_t size; | |
3494927e | 40 | u64 version; |
69e34551 MS |
41 | unsigned int offset; |
42 | void *addr; | |
43 | ||
44 | spin_lock(&fi->rdc.lock); | |
45 | /* | |
46 | * Is cache already completed? Or this entry does not go at the end of | |
47 | * cache? | |
48 | */ | |
49 | if (fi->rdc.cached || pos != fi->rdc.pos) { | |
50 | spin_unlock(&fi->rdc.lock); | |
51 | return; | |
52 | } | |
3494927e | 53 | version = fi->rdc.version; |
69e34551 MS |
54 | size = fi->rdc.size; |
55 | offset = size & ~PAGE_MASK; | |
56 | index = size >> PAGE_SHIFT; | |
57 | /* Dirent doesn't fit in current page? Jump to next page. */ | |
58 | if (offset + reclen > PAGE_SIZE) { | |
59 | index++; | |
60 | offset = 0; | |
61 | } | |
62 | spin_unlock(&fi->rdc.lock); | |
63 | ||
64 | if (offset) { | |
65 | page = find_lock_page(file->f_mapping, index); | |
66 | } else { | |
67 | page = find_or_create_page(file->f_mapping, index, | |
68 | mapping_gfp_mask(file->f_mapping)); | |
69 | } | |
70 | if (!page) | |
71 | return; | |
72 | ||
73 | spin_lock(&fi->rdc.lock); | |
74 | /* Raced with another readdir */ | |
3494927e MS |
75 | if (fi->rdc.version != version || fi->rdc.size != size || |
76 | WARN_ON(fi->rdc.pos != pos)) | |
69e34551 MS |
77 | goto unlock; |
78 | ||
79 | addr = kmap_atomic(page); | |
80 | if (!offset) | |
81 | clear_page(addr); | |
82 | memcpy(addr + offset, dirent, reclen); | |
83 | kunmap_atomic(addr); | |
84 | fi->rdc.size = (index << PAGE_SHIFT) + offset + reclen; | |
85 | fi->rdc.pos = dirent->off; | |
86 | unlock: | |
87 | spin_unlock(&fi->rdc.lock); | |
88 | unlock_page(page); | |
89 | put_page(page); | |
90 | } | |
91 | ||
92 | static void fuse_readdir_cache_end(struct file *file, loff_t pos) | |
93 | { | |
94 | struct fuse_inode *fi = get_fuse_inode(file_inode(file)); | |
95 | loff_t end; | |
96 | ||
97 | spin_lock(&fi->rdc.lock); | |
98 | /* does cache end position match current position? */ | |
99 | if (fi->rdc.pos != pos) { | |
100 | spin_unlock(&fi->rdc.lock); | |
101 | return; | |
102 | } | |
103 | ||
104 | fi->rdc.cached = true; | |
105 | end = ALIGN(fi->rdc.size, PAGE_SIZE); | |
106 | spin_unlock(&fi->rdc.lock); | |
107 | ||
108 | /* truncate unused tail of cache */ | |
109 | truncate_inode_pages(file->f_mapping, end); | |
110 | } | |
111 | ||
18172b10 MS |
112 | static bool fuse_emit(struct file *file, struct dir_context *ctx, |
113 | struct fuse_dirent *dirent) | |
114 | { | |
69e34551 MS |
115 | struct fuse_file *ff = file->private_data; |
116 | ||
117 | if (ff->open_flags & FOPEN_CACHE_DIR) | |
118 | fuse_add_dirent_to_cache(file, dirent, ctx->pos); | |
119 | ||
18172b10 MS |
120 | return dir_emit(ctx, dirent->name, dirent->namelen, dirent->ino, |
121 | dirent->type); | |
122 | } | |
123 | ||
d123d8e1 MS |
124 | static int parse_dirfile(char *buf, size_t nbytes, struct file *file, |
125 | struct dir_context *ctx) | |
126 | { | |
127 | while (nbytes >= FUSE_NAME_OFFSET) { | |
128 | struct fuse_dirent *dirent = (struct fuse_dirent *) buf; | |
129 | size_t reclen = FUSE_DIRENT_SIZE(dirent); | |
130 | if (!dirent->namelen || dirent->namelen > FUSE_NAME_MAX) | |
131 | return -EIO; | |
132 | if (reclen > nbytes) | |
133 | break; | |
134 | if (memchr(dirent->name, '/', dirent->namelen) != NULL) | |
135 | return -EIO; | |
136 | ||
18172b10 | 137 | if (!fuse_emit(file, ctx, dirent)) |
d123d8e1 MS |
138 | break; |
139 | ||
140 | buf += reclen; | |
141 | nbytes -= reclen; | |
142 | ctx->pos = dirent->off; | |
143 | } | |
144 | ||
145 | return 0; | |
146 | } | |
147 | ||
148 | static int fuse_direntplus_link(struct file *file, | |
149 | struct fuse_direntplus *direntplus, | |
150 | u64 attr_version) | |
151 | { | |
152 | struct fuse_entry_out *o = &direntplus->entry_out; | |
153 | struct fuse_dirent *dirent = &direntplus->dirent; | |
154 | struct dentry *parent = file->f_path.dentry; | |
155 | struct qstr name = QSTR_INIT(dirent->name, dirent->namelen); | |
156 | struct dentry *dentry; | |
157 | struct dentry *alias; | |
158 | struct inode *dir = d_inode(parent); | |
159 | struct fuse_conn *fc; | |
160 | struct inode *inode; | |
161 | DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq); | |
162 | ||
163 | if (!o->nodeid) { | |
164 | /* | |
165 | * Unlike in the case of fuse_lookup, zero nodeid does not mean | |
166 | * ENOENT. Instead, it only means the userspace filesystem did | |
167 | * not want to return attributes/handle for this entry. | |
168 | * | |
169 | * So do nothing. | |
170 | */ | |
171 | return 0; | |
172 | } | |
173 | ||
174 | if (name.name[0] == '.') { | |
175 | /* | |
176 | * We could potentially refresh the attributes of the directory | |
177 | * and its parent? | |
178 | */ | |
179 | if (name.len == 1) | |
180 | return 0; | |
181 | if (name.name[1] == '.' && name.len == 2) | |
182 | return 0; | |
183 | } | |
184 | ||
185 | if (invalid_nodeid(o->nodeid)) | |
186 | return -EIO; | |
187 | if (!fuse_valid_type(o->attr.mode)) | |
188 | return -EIO; | |
189 | ||
190 | fc = get_fuse_conn(dir); | |
191 | ||
192 | name.hash = full_name_hash(parent, name.name, name.len); | |
193 | dentry = d_lookup(parent, &name); | |
194 | if (!dentry) { | |
195 | retry: | |
196 | dentry = d_alloc_parallel(parent, &name, &wq); | |
197 | if (IS_ERR(dentry)) | |
198 | return PTR_ERR(dentry); | |
199 | } | |
200 | if (!d_in_lookup(dentry)) { | |
201 | struct fuse_inode *fi; | |
202 | inode = d_inode(dentry); | |
203 | if (!inode || | |
204 | get_node_id(inode) != o->nodeid || | |
205 | ((o->attr.mode ^ inode->i_mode) & S_IFMT)) { | |
206 | d_invalidate(dentry); | |
207 | dput(dentry); | |
208 | goto retry; | |
209 | } | |
210 | if (is_bad_inode(inode)) { | |
211 | dput(dentry); | |
212 | return -EIO; | |
213 | } | |
214 | ||
215 | fi = get_fuse_inode(inode); | |
216 | spin_lock(&fc->lock); | |
217 | fi->nlookup++; | |
218 | spin_unlock(&fc->lock); | |
219 | ||
220 | forget_all_cached_acls(inode); | |
221 | fuse_change_attributes(inode, &o->attr, | |
222 | entry_attr_timeout(o), | |
223 | attr_version); | |
224 | /* | |
225 | * The other branch comes via fuse_iget() | |
226 | * which bumps nlookup inside | |
227 | */ | |
228 | } else { | |
229 | inode = fuse_iget(dir->i_sb, o->nodeid, o->generation, | |
230 | &o->attr, entry_attr_timeout(o), | |
231 | attr_version); | |
232 | if (!inode) | |
233 | inode = ERR_PTR(-ENOMEM); | |
234 | ||
235 | alias = d_splice_alias(inode, dentry); | |
236 | d_lookup_done(dentry); | |
237 | if (alias) { | |
238 | dput(dentry); | |
239 | dentry = alias; | |
240 | } | |
241 | if (IS_ERR(dentry)) | |
242 | return PTR_ERR(dentry); | |
243 | } | |
244 | if (fc->readdirplus_auto) | |
245 | set_bit(FUSE_I_INIT_RDPLUS, &get_fuse_inode(inode)->state); | |
246 | fuse_change_entry_timeout(dentry, o); | |
247 | ||
248 | dput(dentry); | |
249 | return 0; | |
250 | } | |
251 | ||
252 | static int parse_dirplusfile(char *buf, size_t nbytes, struct file *file, | |
253 | struct dir_context *ctx, u64 attr_version) | |
254 | { | |
255 | struct fuse_direntplus *direntplus; | |
256 | struct fuse_dirent *dirent; | |
257 | size_t reclen; | |
258 | int over = 0; | |
259 | int ret; | |
260 | ||
261 | while (nbytes >= FUSE_NAME_OFFSET_DIRENTPLUS) { | |
262 | direntplus = (struct fuse_direntplus *) buf; | |
263 | dirent = &direntplus->dirent; | |
264 | reclen = FUSE_DIRENTPLUS_SIZE(direntplus); | |
265 | ||
266 | if (!dirent->namelen || dirent->namelen > FUSE_NAME_MAX) | |
267 | return -EIO; | |
268 | if (reclen > nbytes) | |
269 | break; | |
270 | if (memchr(dirent->name, '/', dirent->namelen) != NULL) | |
271 | return -EIO; | |
272 | ||
273 | if (!over) { | |
274 | /* We fill entries into dstbuf only as much as | |
275 | it can hold. But we still continue iterating | |
276 | over remaining entries to link them. If not, | |
277 | we need to send a FORGET for each of those | |
278 | which we did not link. | |
279 | */ | |
18172b10 | 280 | over = !fuse_emit(file, ctx, dirent); |
d123d8e1 MS |
281 | if (!over) |
282 | ctx->pos = dirent->off; | |
283 | } | |
284 | ||
285 | buf += reclen; | |
286 | nbytes -= reclen; | |
287 | ||
288 | ret = fuse_direntplus_link(file, direntplus, attr_version); | |
289 | if (ret) | |
290 | fuse_force_forget(file, direntplus->entry_out.nodeid); | |
291 | } | |
292 | ||
293 | return 0; | |
294 | } | |
295 | ||
5d7bc7e8 | 296 | static int fuse_readdir_uncached(struct file *file, struct dir_context *ctx) |
d123d8e1 MS |
297 | { |
298 | int plus, err; | |
299 | size_t nbytes; | |
300 | struct page *page; | |
301 | struct inode *inode = file_inode(file); | |
302 | struct fuse_conn *fc = get_fuse_conn(inode); | |
303 | struct fuse_req *req; | |
304 | u64 attr_version = 0; | |
305 | bool locked; | |
306 | ||
d123d8e1 MS |
307 | req = fuse_get_req(fc, 1); |
308 | if (IS_ERR(req)) | |
309 | return PTR_ERR(req); | |
310 | ||
311 | page = alloc_page(GFP_KERNEL); | |
312 | if (!page) { | |
313 | fuse_put_request(fc, req); | |
314 | return -ENOMEM; | |
315 | } | |
316 | ||
317 | plus = fuse_use_readdirplus(inode, ctx); | |
318 | req->out.argpages = 1; | |
319 | req->num_pages = 1; | |
320 | req->pages[0] = page; | |
321 | req->page_descs[0].length = PAGE_SIZE; | |
322 | if (plus) { | |
323 | attr_version = fuse_get_attr_version(fc); | |
324 | fuse_read_fill(req, file, ctx->pos, PAGE_SIZE, | |
325 | FUSE_READDIRPLUS); | |
326 | } else { | |
327 | fuse_read_fill(req, file, ctx->pos, PAGE_SIZE, | |
328 | FUSE_READDIR); | |
329 | } | |
330 | locked = fuse_lock_inode(inode); | |
331 | fuse_request_send(fc, req); | |
332 | fuse_unlock_inode(inode, locked); | |
333 | nbytes = req->out.args[0].size; | |
334 | err = req->out.h.error; | |
335 | fuse_put_request(fc, req); | |
336 | if (!err) { | |
69e34551 MS |
337 | if (!nbytes) { |
338 | struct fuse_file *ff = file->private_data; | |
339 | ||
340 | if (ff->open_flags & FOPEN_CACHE_DIR) | |
341 | fuse_readdir_cache_end(file, ctx->pos); | |
342 | } else if (plus) { | |
d123d8e1 MS |
343 | err = parse_dirplusfile(page_address(page), nbytes, |
344 | file, ctx, attr_version); | |
345 | } else { | |
346 | err = parse_dirfile(page_address(page), nbytes, file, | |
347 | ctx); | |
348 | } | |
349 | } | |
350 | ||
351 | __free_page(page); | |
352 | fuse_invalidate_atime(inode); | |
353 | return err; | |
354 | } | |
5d7bc7e8 MS |
355 | |
356 | enum fuse_parse_result { | |
357 | FOUND_ERR = -1, | |
358 | FOUND_NONE = 0, | |
359 | FOUND_SOME, | |
360 | FOUND_ALL, | |
361 | }; | |
362 | ||
363 | static enum fuse_parse_result fuse_parse_cache(struct fuse_file *ff, | |
364 | void *addr, unsigned int size, | |
365 | struct dir_context *ctx) | |
366 | { | |
367 | unsigned int offset = ff->readdir.cache_off & ~PAGE_MASK; | |
368 | enum fuse_parse_result res = FOUND_NONE; | |
369 | ||
370 | WARN_ON(offset >= size); | |
371 | ||
372 | for (;;) { | |
373 | struct fuse_dirent *dirent = addr + offset; | |
374 | unsigned int nbytes = size - offset; | |
375 | size_t reclen = FUSE_DIRENT_SIZE(dirent); | |
376 | ||
377 | if (nbytes < FUSE_NAME_OFFSET || !dirent->namelen) | |
378 | break; | |
379 | ||
380 | if (WARN_ON(dirent->namelen > FUSE_NAME_MAX)) | |
381 | return FOUND_ERR; | |
382 | if (WARN_ON(reclen > nbytes)) | |
383 | return FOUND_ERR; | |
384 | if (WARN_ON(memchr(dirent->name, '/', dirent->namelen) != NULL)) | |
385 | return FOUND_ERR; | |
386 | ||
387 | if (ff->readdir.pos == ctx->pos) { | |
388 | res = FOUND_SOME; | |
389 | if (!dir_emit(ctx, dirent->name, dirent->namelen, | |
390 | dirent->ino, dirent->type)) | |
391 | return FOUND_ALL; | |
392 | ctx->pos = dirent->off; | |
393 | } | |
394 | ff->readdir.pos = dirent->off; | |
395 | ff->readdir.cache_off += reclen; | |
396 | ||
397 | offset += reclen; | |
398 | } | |
399 | ||
400 | return res; | |
401 | } | |
402 | ||
7118883b | 403 | static void fuse_rdc_reset(struct inode *inode) |
3494927e | 404 | { |
7118883b MS |
405 | struct fuse_inode *fi = get_fuse_inode(inode); |
406 | ||
3494927e MS |
407 | fi->rdc.cached = false; |
408 | fi->rdc.version++; | |
409 | fi->rdc.size = 0; | |
410 | fi->rdc.pos = 0; | |
411 | } | |
412 | ||
5d7bc7e8 MS |
413 | #define UNCACHED 1 |
414 | ||
415 | static int fuse_readdir_cached(struct file *file, struct dir_context *ctx) | |
416 | { | |
417 | struct fuse_file *ff = file->private_data; | |
418 | struct inode *inode = file_inode(file); | |
7118883b | 419 | struct fuse_conn *fc = get_fuse_conn(inode); |
5d7bc7e8 MS |
420 | struct fuse_inode *fi = get_fuse_inode(inode); |
421 | enum fuse_parse_result res; | |
422 | pgoff_t index; | |
423 | unsigned int size; | |
424 | struct page *page; | |
425 | void *addr; | |
426 | ||
427 | /* Seeked? If so, reset the cache stream */ | |
428 | if (ff->readdir.pos != ctx->pos) { | |
429 | ff->readdir.pos = 0; | |
430 | ff->readdir.cache_off = 0; | |
431 | } | |
432 | ||
7118883b MS |
433 | /* |
434 | * We're just about to start reading into the cache or reading the | |
435 | * cache; both cases require an up-to-date mtime value. | |
436 | */ | |
437 | if (!ctx->pos && fc->auto_inval_data) { | |
438 | int err = fuse_update_attributes(inode, file); | |
439 | ||
440 | if (err) | |
441 | return err; | |
442 | } | |
443 | ||
5d7bc7e8 MS |
444 | retry: |
445 | spin_lock(&fi->rdc.lock); | |
7118883b | 446 | retry_locked: |
5d7bc7e8 | 447 | if (!fi->rdc.cached) { |
7118883b MS |
448 | /* Starting cache? Set cache mtime. */ |
449 | if (!ctx->pos && !fi->rdc.size) { | |
450 | fi->rdc.mtime = inode->i_mtime; | |
261aaba7 | 451 | fi->rdc.iversion = inode_query_iversion(inode); |
7118883b | 452 | } |
5d7bc7e8 MS |
453 | spin_unlock(&fi->rdc.lock); |
454 | return UNCACHED; | |
455 | } | |
7118883b MS |
456 | /* |
457 | * When at the beginning of the directory (i.e. just after opendir(3) or | |
458 | * rewinddir(3)), then need to check whether directory contents have | |
459 | * changed, and reset the cache if so. | |
460 | */ | |
461 | if (!ctx->pos) { | |
261aaba7 MS |
462 | if (inode_peek_iversion(inode) != fi->rdc.iversion || |
463 | !timespec64_equal(&fi->rdc.mtime, &inode->i_mtime)) { | |
7118883b MS |
464 | fuse_rdc_reset(inode); |
465 | goto retry_locked; | |
466 | } | |
467 | } | |
468 | ||
3494927e MS |
469 | /* |
470 | * If cache version changed since the last getdents() call, then reset | |
471 | * the cache stream. | |
472 | */ | |
473 | if (ff->readdir.version != fi->rdc.version) { | |
474 | ff->readdir.pos = 0; | |
475 | ff->readdir.cache_off = 0; | |
476 | } | |
477 | /* | |
478 | * If at the beginning of the cache, than reset version to | |
479 | * current. | |
480 | */ | |
481 | if (ff->readdir.pos == 0) | |
482 | ff->readdir.version = fi->rdc.version; | |
483 | ||
5d7bc7e8 MS |
484 | WARN_ON(fi->rdc.size < ff->readdir.cache_off); |
485 | ||
486 | index = ff->readdir.cache_off >> PAGE_SHIFT; | |
487 | ||
488 | if (index == (fi->rdc.size >> PAGE_SHIFT)) | |
489 | size = fi->rdc.size & ~PAGE_MASK; | |
490 | else | |
491 | size = PAGE_SIZE; | |
492 | spin_unlock(&fi->rdc.lock); | |
493 | ||
494 | /* EOF? */ | |
495 | if ((ff->readdir.cache_off & ~PAGE_MASK) == size) | |
496 | return 0; | |
497 | ||
498 | page = find_get_page_flags(file->f_mapping, index, | |
499 | FGP_ACCESSED | FGP_LOCK); | |
3494927e | 500 | spin_lock(&fi->rdc.lock); |
5d7bc7e8 MS |
501 | if (!page) { |
502 | /* | |
503 | * Uh-oh: page gone missing, cache is useless | |
504 | */ | |
3494927e | 505 | if (fi->rdc.version == ff->readdir.version) |
7118883b MS |
506 | fuse_rdc_reset(inode); |
507 | goto retry_locked; | |
5d7bc7e8 MS |
508 | } |
509 | ||
3494927e MS |
510 | /* Make sure it's still the same version after getting the page. */ |
511 | if (ff->readdir.version != fi->rdc.version) { | |
512 | spin_unlock(&fi->rdc.lock); | |
513 | unlock_page(page); | |
514 | put_page(page); | |
515 | goto retry; | |
516 | } | |
517 | spin_unlock(&fi->rdc.lock); | |
518 | ||
519 | /* | |
520 | * Contents of the page are now protected against changing by holding | |
521 | * the page lock. | |
522 | */ | |
5d7bc7e8 MS |
523 | addr = kmap(page); |
524 | res = fuse_parse_cache(ff, addr, size, ctx); | |
525 | kunmap(page); | |
526 | unlock_page(page); | |
527 | put_page(page); | |
528 | ||
529 | if (res == FOUND_ERR) | |
530 | return -EIO; | |
531 | ||
532 | if (res == FOUND_ALL) | |
533 | return 0; | |
534 | ||
535 | if (size == PAGE_SIZE) { | |
536 | /* We hit end of page: skip to next page. */ | |
537 | ff->readdir.cache_off = ALIGN(ff->readdir.cache_off, PAGE_SIZE); | |
538 | goto retry; | |
539 | } | |
540 | ||
541 | /* | |
542 | * End of cache reached. If found position, then we are done, otherwise | |
543 | * need to fall back to uncached, since the position we were looking for | |
544 | * wasn't in the cache. | |
545 | */ | |
546 | return res == FOUND_SOME ? 0 : UNCACHED; | |
547 | } | |
548 | ||
549 | int fuse_readdir(struct file *file, struct dir_context *ctx) | |
550 | { | |
551 | struct fuse_file *ff = file->private_data; | |
552 | struct inode *inode = file_inode(file); | |
553 | int err; | |
554 | ||
555 | if (is_bad_inode(inode)) | |
556 | return -EIO; | |
557 | ||
558 | mutex_lock(&ff->readdir.lock); | |
559 | ||
560 | err = UNCACHED; | |
561 | if (ff->open_flags & FOPEN_CACHE_DIR) | |
562 | err = fuse_readdir_cached(file, ctx); | |
563 | if (err == UNCACHED) | |
564 | err = fuse_readdir_uncached(file, ctx); | |
565 | ||
566 | mutex_unlock(&ff->readdir.lock); | |
567 | ||
568 | return err; | |
569 | } |