Root/
1 | /* |
2 | FUSE: Filesystem in Userspace |
3 | Copyright (C) 2001-2008 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 | #include "fuse_i.h" |
10 | |
11 | #include <linux/pagemap.h> |
12 | #include <linux/slab.h> |
13 | #include <linux/kernel.h> |
14 | #include <linux/sched.h> |
15 | #include <linux/module.h> |
16 | |
17 | static const struct file_operations fuse_direct_io_file_operations; |
18 | |
19 | static int fuse_send_open(struct fuse_conn *fc, u64 nodeid, struct file *file, |
20 | int opcode, struct fuse_open_out *outargp) |
21 | { |
22 | struct fuse_open_in inarg; |
23 | struct fuse_req *req; |
24 | int err; |
25 | |
26 | req = fuse_get_req(fc); |
27 | if (IS_ERR(req)) |
28 | return PTR_ERR(req); |
29 | |
30 | memset(&inarg, 0, sizeof(inarg)); |
31 | inarg.flags = file->f_flags & ~(O_CREAT | O_EXCL | O_NOCTTY); |
32 | if (!fc->atomic_o_trunc) |
33 | inarg.flags &= ~O_TRUNC; |
34 | req->in.h.opcode = opcode; |
35 | req->in.h.nodeid = nodeid; |
36 | req->in.numargs = 1; |
37 | req->in.args[0].size = sizeof(inarg); |
38 | req->in.args[0].value = &inarg; |
39 | req->out.numargs = 1; |
40 | req->out.args[0].size = sizeof(*outargp); |
41 | req->out.args[0].value = outargp; |
42 | fuse_request_send(fc, req); |
43 | err = req->out.h.error; |
44 | fuse_put_request(fc, req); |
45 | |
46 | return err; |
47 | } |
48 | |
49 | struct fuse_file *fuse_file_alloc(struct fuse_conn *fc) |
50 | { |
51 | struct fuse_file *ff; |
52 | |
53 | ff = kmalloc(sizeof(struct fuse_file), GFP_KERNEL); |
54 | if (unlikely(!ff)) |
55 | return NULL; |
56 | |
57 | ff->fc = fc; |
58 | ff->reserved_req = fuse_request_alloc(); |
59 | if (unlikely(!ff->reserved_req)) { |
60 | kfree(ff); |
61 | return NULL; |
62 | } |
63 | |
64 | INIT_LIST_HEAD(&ff->write_entry); |
65 | atomic_set(&ff->count, 0); |
66 | RB_CLEAR_NODE(&ff->polled_node); |
67 | init_waitqueue_head(&ff->poll_wait); |
68 | |
69 | spin_lock(&fc->lock); |
70 | ff->kh = ++fc->khctr; |
71 | spin_unlock(&fc->lock); |
72 | |
73 | return ff; |
74 | } |
75 | |
76 | void fuse_file_free(struct fuse_file *ff) |
77 | { |
78 | fuse_request_free(ff->reserved_req); |
79 | kfree(ff); |
80 | } |
81 | |
82 | struct fuse_file *fuse_file_get(struct fuse_file *ff) |
83 | { |
84 | atomic_inc(&ff->count); |
85 | return ff; |
86 | } |
87 | |
88 | static void fuse_release_end(struct fuse_conn *fc, struct fuse_req *req) |
89 | { |
90 | path_put(&req->misc.release.path); |
91 | } |
92 | |
93 | static void fuse_file_put(struct fuse_file *ff) |
94 | { |
95 | if (atomic_dec_and_test(&ff->count)) { |
96 | struct fuse_req *req = ff->reserved_req; |
97 | |
98 | req->end = fuse_release_end; |
99 | fuse_request_send_background(ff->fc, req); |
100 | kfree(ff); |
101 | } |
102 | } |
103 | |
104 | int fuse_do_open(struct fuse_conn *fc, u64 nodeid, struct file *file, |
105 | bool isdir) |
106 | { |
107 | struct fuse_open_out outarg; |
108 | struct fuse_file *ff; |
109 | int err; |
110 | int opcode = isdir ? FUSE_OPENDIR : FUSE_OPEN; |
111 | |
112 | ff = fuse_file_alloc(fc); |
113 | if (!ff) |
114 | return -ENOMEM; |
115 | |
116 | err = fuse_send_open(fc, nodeid, file, opcode, &outarg); |
117 | if (err) { |
118 | fuse_file_free(ff); |
119 | return err; |
120 | } |
121 | |
122 | if (isdir) |
123 | outarg.open_flags &= ~FOPEN_DIRECT_IO; |
124 | |
125 | ff->fh = outarg.fh; |
126 | ff->nodeid = nodeid; |
127 | ff->open_flags = outarg.open_flags; |
128 | file->private_data = fuse_file_get(ff); |
129 | |
130 | return 0; |
131 | } |
132 | EXPORT_SYMBOL_GPL(fuse_do_open); |
133 | |
134 | void fuse_finish_open(struct inode *inode, struct file *file) |
135 | { |
136 | struct fuse_file *ff = file->private_data; |
137 | |
138 | if (ff->open_flags & FOPEN_DIRECT_IO) |
139 | file->f_op = &fuse_direct_io_file_operations; |
140 | if (!(ff->open_flags & FOPEN_KEEP_CACHE)) |
141 | invalidate_inode_pages2(inode->i_mapping); |
142 | if (ff->open_flags & FOPEN_NONSEEKABLE) |
143 | nonseekable_open(inode, file); |
144 | } |
145 | |
146 | int fuse_open_common(struct inode *inode, struct file *file, bool isdir) |
147 | { |
148 | struct fuse_conn *fc = get_fuse_conn(inode); |
149 | int err; |
150 | |
151 | /* VFS checks this, but only _after_ ->open() */ |
152 | if (file->f_flags & O_DIRECT) |
153 | return -EINVAL; |
154 | |
155 | err = generic_file_open(inode, file); |
156 | if (err) |
157 | return err; |
158 | |
159 | err = fuse_do_open(fc, get_node_id(inode), file, isdir); |
160 | if (err) |
161 | return err; |
162 | |
163 | fuse_finish_open(inode, file); |
164 | |
165 | return 0; |
166 | } |
167 | |
168 | static void fuse_prepare_release(struct fuse_file *ff, int flags, int opcode) |
169 | { |
170 | struct fuse_conn *fc = ff->fc; |
171 | struct fuse_req *req = ff->reserved_req; |
172 | struct fuse_release_in *inarg = &req->misc.release.in; |
173 | |
174 | spin_lock(&fc->lock); |
175 | list_del(&ff->write_entry); |
176 | if (!RB_EMPTY_NODE(&ff->polled_node)) |
177 | rb_erase(&ff->polled_node, &fc->polled_files); |
178 | spin_unlock(&fc->lock); |
179 | |
180 | wake_up_interruptible_sync(&ff->poll_wait); |
181 | |
182 | inarg->fh = ff->fh; |
183 | inarg->flags = flags; |
184 | req->in.h.opcode = opcode; |
185 | req->in.h.nodeid = ff->nodeid; |
186 | req->in.numargs = 1; |
187 | req->in.args[0].size = sizeof(struct fuse_release_in); |
188 | req->in.args[0].value = inarg; |
189 | } |
190 | |
191 | void fuse_release_common(struct file *file, int opcode) |
192 | { |
193 | struct fuse_file *ff; |
194 | struct fuse_req *req; |
195 | |
196 | ff = file->private_data; |
197 | if (unlikely(!ff)) |
198 | return; |
199 | |
200 | req = ff->reserved_req; |
201 | fuse_prepare_release(ff, file->f_flags, opcode); |
202 | |
203 | /* Hold vfsmount and dentry until release is finished */ |
204 | path_get(&file->f_path); |
205 | req->misc.release.path = file->f_path; |
206 | |
207 | /* |
208 | * Normally this will send the RELEASE request, however if |
209 | * some asynchronous READ or WRITE requests are outstanding, |
210 | * the sending will be delayed. |
211 | */ |
212 | fuse_file_put(ff); |
213 | } |
214 | |
215 | static int fuse_open(struct inode *inode, struct file *file) |
216 | { |
217 | return fuse_open_common(inode, file, false); |
218 | } |
219 | |
220 | static int fuse_release(struct inode *inode, struct file *file) |
221 | { |
222 | fuse_release_common(file, FUSE_RELEASE); |
223 | |
224 | /* return value is ignored by VFS */ |
225 | return 0; |
226 | } |
227 | |
228 | void fuse_sync_release(struct fuse_file *ff, int flags) |
229 | { |
230 | WARN_ON(atomic_read(&ff->count) > 1); |
231 | fuse_prepare_release(ff, flags, FUSE_RELEASE); |
232 | ff->reserved_req->force = 1; |
233 | fuse_request_send(ff->fc, ff->reserved_req); |
234 | fuse_put_request(ff->fc, ff->reserved_req); |
235 | kfree(ff); |
236 | } |
237 | EXPORT_SYMBOL_GPL(fuse_sync_release); |
238 | |
239 | /* |
240 | * Scramble the ID space with XTEA, so that the value of the files_struct |
241 | * pointer is not exposed to userspace. |
242 | */ |
243 | u64 fuse_lock_owner_id(struct fuse_conn *fc, fl_owner_t id) |
244 | { |
245 | u32 *k = fc->scramble_key; |
246 | u64 v = (unsigned long) id; |
247 | u32 v0 = v; |
248 | u32 v1 = v >> 32; |
249 | u32 sum = 0; |
250 | int i; |
251 | |
252 | for (i = 0; i < 32; i++) { |
253 | v0 += ((v1 << 4 ^ v1 >> 5) + v1) ^ (sum + k[sum & 3]); |
254 | sum += 0x9E3779B9; |
255 | v1 += ((v0 << 4 ^ v0 >> 5) + v0) ^ (sum + k[sum>>11 & 3]); |
256 | } |
257 | |
258 | return (u64) v0 + ((u64) v1 << 32); |
259 | } |
260 | |
261 | /* |
262 | * Check if page is under writeback |
263 | * |
264 | * This is currently done by walking the list of writepage requests |
265 | * for the inode, which can be pretty inefficient. |
266 | */ |
267 | static bool fuse_page_is_writeback(struct inode *inode, pgoff_t index) |
268 | { |
269 | struct fuse_conn *fc = get_fuse_conn(inode); |
270 | struct fuse_inode *fi = get_fuse_inode(inode); |
271 | struct fuse_req *req; |
272 | bool found = false; |
273 | |
274 | spin_lock(&fc->lock); |
275 | list_for_each_entry(req, &fi->writepages, writepages_entry) { |
276 | pgoff_t curr_index; |
277 | |
278 | BUG_ON(req->inode != inode); |
279 | curr_index = req->misc.write.in.offset >> PAGE_CACHE_SHIFT; |
280 | if (curr_index == index) { |
281 | found = true; |
282 | break; |
283 | } |
284 | } |
285 | spin_unlock(&fc->lock); |
286 | |
287 | return found; |
288 | } |
289 | |
290 | /* |
291 | * Wait for page writeback to be completed. |
292 | * |
293 | * Since fuse doesn't rely on the VM writeback tracking, this has to |
294 | * use some other means. |
295 | */ |
296 | static int fuse_wait_on_page_writeback(struct inode *inode, pgoff_t index) |
297 | { |
298 | struct fuse_inode *fi = get_fuse_inode(inode); |
299 | |
300 | wait_event(fi->page_waitq, !fuse_page_is_writeback(inode, index)); |
301 | return 0; |
302 | } |
303 | |
304 | static int fuse_flush(struct file *file, fl_owner_t id) |
305 | { |
306 | struct inode *inode = file->f_path.dentry->d_inode; |
307 | struct fuse_conn *fc = get_fuse_conn(inode); |
308 | struct fuse_file *ff = file->private_data; |
309 | struct fuse_req *req; |
310 | struct fuse_flush_in inarg; |
311 | int err; |
312 | |
313 | if (is_bad_inode(inode)) |
314 | return -EIO; |
315 | |
316 | if (fc->no_flush) |
317 | return 0; |
318 | |
319 | req = fuse_get_req_nofail(fc, file); |
320 | memset(&inarg, 0, sizeof(inarg)); |
321 | inarg.fh = ff->fh; |
322 | inarg.lock_owner = fuse_lock_owner_id(fc, id); |
323 | req->in.h.opcode = FUSE_FLUSH; |
324 | req->in.h.nodeid = get_node_id(inode); |
325 | req->in.numargs = 1; |
326 | req->in.args[0].size = sizeof(inarg); |
327 | req->in.args[0].value = &inarg; |
328 | req->force = 1; |
329 | fuse_request_send(fc, req); |
330 | err = req->out.h.error; |
331 | fuse_put_request(fc, req); |
332 | if (err == -ENOSYS) { |
333 | fc->no_flush = 1; |
334 | err = 0; |
335 | } |
336 | return err; |
337 | } |
338 | |
339 | /* |
340 | * Wait for all pending writepages on the inode to finish. |
341 | * |
342 | * This is currently done by blocking further writes with FUSE_NOWRITE |
343 | * and waiting for all sent writes to complete. |
344 | * |
345 | * This must be called under i_mutex, otherwise the FUSE_NOWRITE usage |
346 | * could conflict with truncation. |
347 | */ |
348 | static void fuse_sync_writes(struct inode *inode) |
349 | { |
350 | fuse_set_nowrite(inode); |
351 | fuse_release_nowrite(inode); |
352 | } |
353 | |
354 | int fuse_fsync_common(struct file *file, struct dentry *de, int datasync, |
355 | int isdir) |
356 | { |
357 | struct inode *inode = de->d_inode; |
358 | struct fuse_conn *fc = get_fuse_conn(inode); |
359 | struct fuse_file *ff = file->private_data; |
360 | struct fuse_req *req; |
361 | struct fuse_fsync_in inarg; |
362 | int err; |
363 | |
364 | if (is_bad_inode(inode)) |
365 | return -EIO; |
366 | |
367 | if ((!isdir && fc->no_fsync) || (isdir && fc->no_fsyncdir)) |
368 | return 0; |
369 | |
370 | /* |
371 | * Start writeback against all dirty pages of the inode, then |
372 | * wait for all outstanding writes, before sending the FSYNC |
373 | * request. |
374 | */ |
375 | err = write_inode_now(inode, 0); |
376 | if (err) |
377 | return err; |
378 | |
379 | fuse_sync_writes(inode); |
380 | |
381 | req = fuse_get_req(fc); |
382 | if (IS_ERR(req)) |
383 | return PTR_ERR(req); |
384 | |
385 | memset(&inarg, 0, sizeof(inarg)); |
386 | inarg.fh = ff->fh; |
387 | inarg.fsync_flags = datasync ? 1 : 0; |
388 | req->in.h.opcode = isdir ? FUSE_FSYNCDIR : FUSE_FSYNC; |
389 | req->in.h.nodeid = get_node_id(inode); |
390 | req->in.numargs = 1; |
391 | req->in.args[0].size = sizeof(inarg); |
392 | req->in.args[0].value = &inarg; |
393 | fuse_request_send(fc, req); |
394 | err = req->out.h.error; |
395 | fuse_put_request(fc, req); |
396 | if (err == -ENOSYS) { |
397 | if (isdir) |
398 | fc->no_fsyncdir = 1; |
399 | else |
400 | fc->no_fsync = 1; |
401 | err = 0; |
402 | } |
403 | return err; |
404 | } |
405 | |
406 | static int fuse_fsync(struct file *file, struct dentry *de, int datasync) |
407 | { |
408 | return fuse_fsync_common(file, de, datasync, 0); |
409 | } |
410 | |
411 | void fuse_read_fill(struct fuse_req *req, struct file *file, loff_t pos, |
412 | size_t count, int opcode) |
413 | { |
414 | struct fuse_read_in *inarg = &req->misc.read.in; |
415 | struct fuse_file *ff = file->private_data; |
416 | |
417 | inarg->fh = ff->fh; |
418 | inarg->offset = pos; |
419 | inarg->size = count; |
420 | inarg->flags = file->f_flags; |
421 | req->in.h.opcode = opcode; |
422 | req->in.h.nodeid = ff->nodeid; |
423 | req->in.numargs = 1; |
424 | req->in.args[0].size = sizeof(struct fuse_read_in); |
425 | req->in.args[0].value = inarg; |
426 | req->out.argvar = 1; |
427 | req->out.numargs = 1; |
428 | req->out.args[0].size = count; |
429 | } |
430 | |
431 | static size_t fuse_send_read(struct fuse_req *req, struct file *file, |
432 | loff_t pos, size_t count, fl_owner_t owner) |
433 | { |
434 | struct fuse_file *ff = file->private_data; |
435 | struct fuse_conn *fc = ff->fc; |
436 | |
437 | fuse_read_fill(req, file, pos, count, FUSE_READ); |
438 | if (owner != NULL) { |
439 | struct fuse_read_in *inarg = &req->misc.read.in; |
440 | |
441 | inarg->read_flags |= FUSE_READ_LOCKOWNER; |
442 | inarg->lock_owner = fuse_lock_owner_id(fc, owner); |
443 | } |
444 | fuse_request_send(fc, req); |
445 | return req->out.args[0].size; |
446 | } |
447 | |
448 | static void fuse_read_update_size(struct inode *inode, loff_t size, |
449 | u64 attr_ver) |
450 | { |
451 | struct fuse_conn *fc = get_fuse_conn(inode); |
452 | struct fuse_inode *fi = get_fuse_inode(inode); |
453 | |
454 | spin_lock(&fc->lock); |
455 | if (attr_ver == fi->attr_version && size < inode->i_size) { |
456 | fi->attr_version = ++fc->attr_version; |
457 | i_size_write(inode, size); |
458 | } |
459 | spin_unlock(&fc->lock); |
460 | } |
461 | |
462 | static int fuse_readpage(struct file *file, struct page *page) |
463 | { |
464 | struct inode *inode = page->mapping->host; |
465 | struct fuse_conn *fc = get_fuse_conn(inode); |
466 | struct fuse_req *req; |
467 | size_t num_read; |
468 | loff_t pos = page_offset(page); |
469 | size_t count = PAGE_CACHE_SIZE; |
470 | u64 attr_ver; |
471 | int err; |
472 | |
473 | err = -EIO; |
474 | if (is_bad_inode(inode)) |
475 | goto out; |
476 | |
477 | /* |
478 | * Page writeback can extend beyond the liftime of the |
479 | * page-cache page, so make sure we read a properly synced |
480 | * page. |
481 | */ |
482 | fuse_wait_on_page_writeback(inode, page->index); |
483 | |
484 | req = fuse_get_req(fc); |
485 | err = PTR_ERR(req); |
486 | if (IS_ERR(req)) |
487 | goto out; |
488 | |
489 | attr_ver = fuse_get_attr_version(fc); |
490 | |
491 | req->out.page_zeroing = 1; |
492 | req->out.argpages = 1; |
493 | req->num_pages = 1; |
494 | req->pages[0] = page; |
495 | num_read = fuse_send_read(req, file, pos, count, NULL); |
496 | err = req->out.h.error; |
497 | fuse_put_request(fc, req); |
498 | |
499 | if (!err) { |
500 | /* |
501 | * Short read means EOF. If file size is larger, truncate it |
502 | */ |
503 | if (num_read < count) |
504 | fuse_read_update_size(inode, pos + num_read, attr_ver); |
505 | |
506 | SetPageUptodate(page); |
507 | } |
508 | |
509 | fuse_invalidate_attr(inode); /* atime changed */ |
510 | out: |
511 | unlock_page(page); |
512 | return err; |
513 | } |
514 | |
515 | static void fuse_readpages_end(struct fuse_conn *fc, struct fuse_req *req) |
516 | { |
517 | int i; |
518 | size_t count = req->misc.read.in.size; |
519 | size_t num_read = req->out.args[0].size; |
520 | struct inode *inode = req->pages[0]->mapping->host; |
521 | |
522 | /* |
523 | * Short read means EOF. If file size is larger, truncate it |
524 | */ |
525 | if (!req->out.h.error && num_read < count) { |
526 | loff_t pos = page_offset(req->pages[0]) + num_read; |
527 | fuse_read_update_size(inode, pos, req->misc.read.attr_ver); |
528 | } |
529 | |
530 | fuse_invalidate_attr(inode); /* atime changed */ |
531 | |
532 | for (i = 0; i < req->num_pages; i++) { |
533 | struct page *page = req->pages[i]; |
534 | if (!req->out.h.error) |
535 | SetPageUptodate(page); |
536 | else |
537 | SetPageError(page); |
538 | unlock_page(page); |
539 | } |
540 | if (req->ff) |
541 | fuse_file_put(req->ff); |
542 | } |
543 | |
544 | static void fuse_send_readpages(struct fuse_req *req, struct file *file) |
545 | { |
546 | struct fuse_file *ff = file->private_data; |
547 | struct fuse_conn *fc = ff->fc; |
548 | loff_t pos = page_offset(req->pages[0]); |
549 | size_t count = req->num_pages << PAGE_CACHE_SHIFT; |
550 | |
551 | req->out.argpages = 1; |
552 | req->out.page_zeroing = 1; |
553 | fuse_read_fill(req, file, pos, count, FUSE_READ); |
554 | req->misc.read.attr_ver = fuse_get_attr_version(fc); |
555 | if (fc->async_read) { |
556 | req->ff = fuse_file_get(ff); |
557 | req->end = fuse_readpages_end; |
558 | fuse_request_send_background(fc, req); |
559 | } else { |
560 | fuse_request_send(fc, req); |
561 | fuse_readpages_end(fc, req); |
562 | fuse_put_request(fc, req); |
563 | } |
564 | } |
565 | |
566 | struct fuse_fill_data { |
567 | struct fuse_req *req; |
568 | struct file *file; |
569 | struct inode *inode; |
570 | }; |
571 | |
572 | static int fuse_readpages_fill(void *_data, struct page *page) |
573 | { |
574 | struct fuse_fill_data *data = _data; |
575 | struct fuse_req *req = data->req; |
576 | struct inode *inode = data->inode; |
577 | struct fuse_conn *fc = get_fuse_conn(inode); |
578 | |
579 | fuse_wait_on_page_writeback(inode, page->index); |
580 | |
581 | if (req->num_pages && |
582 | (req->num_pages == FUSE_MAX_PAGES_PER_REQ || |
583 | (req->num_pages + 1) * PAGE_CACHE_SIZE > fc->max_read || |
584 | req->pages[req->num_pages - 1]->index + 1 != page->index)) { |
585 | fuse_send_readpages(req, data->file); |
586 | data->req = req = fuse_get_req(fc); |
587 | if (IS_ERR(req)) { |
588 | unlock_page(page); |
589 | return PTR_ERR(req); |
590 | } |
591 | } |
592 | req->pages[req->num_pages] = page; |
593 | req->num_pages++; |
594 | return 0; |
595 | } |
596 | |
597 | static int fuse_readpages(struct file *file, struct address_space *mapping, |
598 | struct list_head *pages, unsigned nr_pages) |
599 | { |
600 | struct inode *inode = mapping->host; |
601 | struct fuse_conn *fc = get_fuse_conn(inode); |
602 | struct fuse_fill_data data; |
603 | int err; |
604 | |
605 | err = -EIO; |
606 | if (is_bad_inode(inode)) |
607 | goto out; |
608 | |
609 | data.file = file; |
610 | data.inode = inode; |
611 | data.req = fuse_get_req(fc); |
612 | err = PTR_ERR(data.req); |
613 | if (IS_ERR(data.req)) |
614 | goto out; |
615 | |
616 | err = read_cache_pages(mapping, pages, fuse_readpages_fill, &data); |
617 | if (!err) { |
618 | if (data.req->num_pages) |
619 | fuse_send_readpages(data.req, file); |
620 | else |
621 | fuse_put_request(fc, data.req); |
622 | } |
623 | out: |
624 | return err; |
625 | } |
626 | |
627 | static ssize_t fuse_file_aio_read(struct kiocb *iocb, const struct iovec *iov, |
628 | unsigned long nr_segs, loff_t pos) |
629 | { |
630 | struct inode *inode = iocb->ki_filp->f_mapping->host; |
631 | |
632 | if (pos + iov_length(iov, nr_segs) > i_size_read(inode)) { |
633 | int err; |
634 | /* |
635 | * If trying to read past EOF, make sure the i_size |
636 | * attribute is up-to-date. |
637 | */ |
638 | err = fuse_update_attributes(inode, NULL, iocb->ki_filp, NULL); |
639 | if (err) |
640 | return err; |
641 | } |
642 | |
643 | return generic_file_aio_read(iocb, iov, nr_segs, pos); |
644 | } |
645 | |
646 | static void fuse_write_fill(struct fuse_req *req, struct fuse_file *ff, |
647 | loff_t pos, size_t count) |
648 | { |
649 | struct fuse_write_in *inarg = &req->misc.write.in; |
650 | struct fuse_write_out *outarg = &req->misc.write.out; |
651 | |
652 | inarg->fh = ff->fh; |
653 | inarg->offset = pos; |
654 | inarg->size = count; |
655 | req->in.h.opcode = FUSE_WRITE; |
656 | req->in.h.nodeid = ff->nodeid; |
657 | req->in.numargs = 2; |
658 | if (ff->fc->minor < 9) |
659 | req->in.args[0].size = FUSE_COMPAT_WRITE_IN_SIZE; |
660 | else |
661 | req->in.args[0].size = sizeof(struct fuse_write_in); |
662 | req->in.args[0].value = inarg; |
663 | req->in.args[1].size = count; |
664 | req->out.numargs = 1; |
665 | req->out.args[0].size = sizeof(struct fuse_write_out); |
666 | req->out.args[0].value = outarg; |
667 | } |
668 | |
669 | static size_t fuse_send_write(struct fuse_req *req, struct file *file, |
670 | loff_t pos, size_t count, fl_owner_t owner) |
671 | { |
672 | struct fuse_file *ff = file->private_data; |
673 | struct fuse_conn *fc = ff->fc; |
674 | struct fuse_write_in *inarg = &req->misc.write.in; |
675 | |
676 | fuse_write_fill(req, ff, pos, count); |
677 | inarg->flags = file->f_flags; |
678 | if (owner != NULL) { |
679 | inarg->write_flags |= FUSE_WRITE_LOCKOWNER; |
680 | inarg->lock_owner = fuse_lock_owner_id(fc, owner); |
681 | } |
682 | fuse_request_send(fc, req); |
683 | return req->misc.write.out.size; |
684 | } |
685 | |
686 | static int fuse_write_begin(struct file *file, struct address_space *mapping, |
687 | loff_t pos, unsigned len, unsigned flags, |
688 | struct page **pagep, void **fsdata) |
689 | { |
690 | pgoff_t index = pos >> PAGE_CACHE_SHIFT; |
691 | |
692 | *pagep = grab_cache_page_write_begin(mapping, index, flags); |
693 | if (!*pagep) |
694 | return -ENOMEM; |
695 | return 0; |
696 | } |
697 | |
698 | static void fuse_write_update_size(struct inode *inode, loff_t pos) |
699 | { |
700 | struct fuse_conn *fc = get_fuse_conn(inode); |
701 | struct fuse_inode *fi = get_fuse_inode(inode); |
702 | |
703 | spin_lock(&fc->lock); |
704 | fi->attr_version = ++fc->attr_version; |
705 | if (pos > inode->i_size) |
706 | i_size_write(inode, pos); |
707 | spin_unlock(&fc->lock); |
708 | } |
709 | |
710 | static int fuse_buffered_write(struct file *file, struct inode *inode, |
711 | loff_t pos, unsigned count, struct page *page) |
712 | { |
713 | int err; |
714 | size_t nres; |
715 | struct fuse_conn *fc = get_fuse_conn(inode); |
716 | unsigned offset = pos & (PAGE_CACHE_SIZE - 1); |
717 | struct fuse_req *req; |
718 | |
719 | if (is_bad_inode(inode)) |
720 | return -EIO; |
721 | |
722 | /* |
723 | * Make sure writepages on the same page are not mixed up with |
724 | * plain writes. |
725 | */ |
726 | fuse_wait_on_page_writeback(inode, page->index); |
727 | |
728 | req = fuse_get_req(fc); |
729 | if (IS_ERR(req)) |
730 | return PTR_ERR(req); |
731 | |
732 | req->in.argpages = 1; |
733 | req->num_pages = 1; |
734 | req->pages[0] = page; |
735 | req->page_offset = offset; |
736 | nres = fuse_send_write(req, file, pos, count, NULL); |
737 | err = req->out.h.error; |
738 | fuse_put_request(fc, req); |
739 | if (!err && !nres) |
740 | err = -EIO; |
741 | if (!err) { |
742 | pos += nres; |
743 | fuse_write_update_size(inode, pos); |
744 | if (count == PAGE_CACHE_SIZE) |
745 | SetPageUptodate(page); |
746 | } |
747 | fuse_invalidate_attr(inode); |
748 | return err ? err : nres; |
749 | } |
750 | |
751 | static int fuse_write_end(struct file *file, struct address_space *mapping, |
752 | loff_t pos, unsigned len, unsigned copied, |
753 | struct page *page, void *fsdata) |
754 | { |
755 | struct inode *inode = mapping->host; |
756 | int res = 0; |
757 | |
758 | if (copied) |
759 | res = fuse_buffered_write(file, inode, pos, copied, page); |
760 | |
761 | unlock_page(page); |
762 | page_cache_release(page); |
763 | return res; |
764 | } |
765 | |
766 | static size_t fuse_send_write_pages(struct fuse_req *req, struct file *file, |
767 | struct inode *inode, loff_t pos, |
768 | size_t count) |
769 | { |
770 | size_t res; |
771 | unsigned offset; |
772 | unsigned i; |
773 | |
774 | for (i = 0; i < req->num_pages; i++) |
775 | fuse_wait_on_page_writeback(inode, req->pages[i]->index); |
776 | |
777 | res = fuse_send_write(req, file, pos, count, NULL); |
778 | |
779 | offset = req->page_offset; |
780 | count = res; |
781 | for (i = 0; i < req->num_pages; i++) { |
782 | struct page *page = req->pages[i]; |
783 | |
784 | if (!req->out.h.error && !offset && count >= PAGE_CACHE_SIZE) |
785 | SetPageUptodate(page); |
786 | |
787 | if (count > PAGE_CACHE_SIZE - offset) |
788 | count -= PAGE_CACHE_SIZE - offset; |
789 | else |
790 | count = 0; |
791 | offset = 0; |
792 | |
793 | unlock_page(page); |
794 | page_cache_release(page); |
795 | } |
796 | |
797 | return res; |
798 | } |
799 | |
800 | static ssize_t fuse_fill_write_pages(struct fuse_req *req, |
801 | struct address_space *mapping, |
802 | struct iov_iter *ii, loff_t pos) |
803 | { |
804 | struct fuse_conn *fc = get_fuse_conn(mapping->host); |
805 | unsigned offset = pos & (PAGE_CACHE_SIZE - 1); |
806 | size_t count = 0; |
807 | int err; |
808 | |
809 | req->in.argpages = 1; |
810 | req->page_offset = offset; |
811 | |
812 | do { |
813 | size_t tmp; |
814 | struct page *page; |
815 | pgoff_t index = pos >> PAGE_CACHE_SHIFT; |
816 | size_t bytes = min_t(size_t, PAGE_CACHE_SIZE - offset, |
817 | iov_iter_count(ii)); |
818 | |
819 | bytes = min_t(size_t, bytes, fc->max_write - count); |
820 | |
821 | again: |
822 | err = -EFAULT; |
823 | if (iov_iter_fault_in_readable(ii, bytes)) |
824 | break; |
825 | |
826 | err = -ENOMEM; |
827 | page = grab_cache_page_write_begin(mapping, index, 0); |
828 | if (!page) |
829 | break; |
830 | |
831 | pagefault_disable(); |
832 | tmp = iov_iter_copy_from_user_atomic(page, ii, offset, bytes); |
833 | pagefault_enable(); |
834 | flush_dcache_page(page); |
835 | |
836 | if (!tmp) { |
837 | unlock_page(page); |
838 | page_cache_release(page); |
839 | bytes = min(bytes, iov_iter_single_seg_count(ii)); |
840 | goto again; |
841 | } |
842 | |
843 | err = 0; |
844 | req->pages[req->num_pages] = page; |
845 | req->num_pages++; |
846 | |
847 | iov_iter_advance(ii, tmp); |
848 | count += tmp; |
849 | pos += tmp; |
850 | offset += tmp; |
851 | if (offset == PAGE_CACHE_SIZE) |
852 | offset = 0; |
853 | |
854 | if (!fc->big_writes) |
855 | break; |
856 | } while (iov_iter_count(ii) && count < fc->max_write && |
857 | req->num_pages < FUSE_MAX_PAGES_PER_REQ && offset == 0); |
858 | |
859 | return count > 0 ? count : err; |
860 | } |
861 | |
862 | static ssize_t fuse_perform_write(struct file *file, |
863 | struct address_space *mapping, |
864 | struct iov_iter *ii, loff_t pos) |
865 | { |
866 | struct inode *inode = mapping->host; |
867 | struct fuse_conn *fc = get_fuse_conn(inode); |
868 | int err = 0; |
869 | ssize_t res = 0; |
870 | |
871 | if (is_bad_inode(inode)) |
872 | return -EIO; |
873 | |
874 | do { |
875 | struct fuse_req *req; |
876 | ssize_t count; |
877 | |
878 | req = fuse_get_req(fc); |
879 | if (IS_ERR(req)) { |
880 | err = PTR_ERR(req); |
881 | break; |
882 | } |
883 | |
884 | count = fuse_fill_write_pages(req, mapping, ii, pos); |
885 | if (count <= 0) { |
886 | err = count; |
887 | } else { |
888 | size_t num_written; |
889 | |
890 | num_written = fuse_send_write_pages(req, file, inode, |
891 | pos, count); |
892 | err = req->out.h.error; |
893 | if (!err) { |
894 | res += num_written; |
895 | pos += num_written; |
896 | |
897 | /* break out of the loop on short write */ |
898 | if (num_written != count) |
899 | err = -EIO; |
900 | } |
901 | } |
902 | fuse_put_request(fc, req); |
903 | } while (!err && iov_iter_count(ii)); |
904 | |
905 | if (res > 0) |
906 | fuse_write_update_size(inode, pos); |
907 | |
908 | fuse_invalidate_attr(inode); |
909 | |
910 | return res > 0 ? res : err; |
911 | } |
912 | |
913 | static ssize_t fuse_file_aio_write(struct kiocb *iocb, const struct iovec *iov, |
914 | unsigned long nr_segs, loff_t pos) |
915 | { |
916 | struct file *file = iocb->ki_filp; |
917 | struct address_space *mapping = file->f_mapping; |
918 | size_t count = 0; |
919 | ssize_t written = 0; |
920 | struct inode *inode = mapping->host; |
921 | ssize_t err; |
922 | struct iov_iter i; |
923 | |
924 | WARN_ON(iocb->ki_pos != pos); |
925 | |
926 | err = generic_segment_checks(iov, &nr_segs, &count, VERIFY_READ); |
927 | if (err) |
928 | return err; |
929 | |
930 | mutex_lock(&inode->i_mutex); |
931 | vfs_check_frozen(inode->i_sb, SB_FREEZE_WRITE); |
932 | |
933 | /* We can write back this queue in page reclaim */ |
934 | current->backing_dev_info = mapping->backing_dev_info; |
935 | |
936 | err = generic_write_checks(file, &pos, &count, S_ISBLK(inode->i_mode)); |
937 | if (err) |
938 | goto out; |
939 | |
940 | if (count == 0) |
941 | goto out; |
942 | |
943 | err = file_remove_suid(file); |
944 | if (err) |
945 | goto out; |
946 | |
947 | file_update_time(file); |
948 | |
949 | iov_iter_init(&i, iov, nr_segs, count, 0); |
950 | written = fuse_perform_write(file, mapping, &i, pos); |
951 | if (written >= 0) |
952 | iocb->ki_pos = pos + written; |
953 | |
954 | out: |
955 | current->backing_dev_info = NULL; |
956 | mutex_unlock(&inode->i_mutex); |
957 | |
958 | return written ? written : err; |
959 | } |
960 | |
961 | static void fuse_release_user_pages(struct fuse_req *req, int write) |
962 | { |
963 | unsigned i; |
964 | |
965 | for (i = 0; i < req->num_pages; i++) { |
966 | struct page *page = req->pages[i]; |
967 | if (write) |
968 | set_page_dirty_lock(page); |
969 | put_page(page); |
970 | } |
971 | } |
972 | |
973 | static int fuse_get_user_pages(struct fuse_req *req, const char __user *buf, |
974 | size_t *nbytesp, int write) |
975 | { |
976 | size_t nbytes = *nbytesp; |
977 | unsigned long user_addr = (unsigned long) buf; |
978 | unsigned offset = user_addr & ~PAGE_MASK; |
979 | int npages; |
980 | |
981 | /* Special case for kernel I/O: can copy directly into the buffer */ |
982 | if (segment_eq(get_fs(), KERNEL_DS)) { |
983 | if (write) |
984 | req->in.args[1].value = (void *) user_addr; |
985 | else |
986 | req->out.args[0].value = (void *) user_addr; |
987 | |
988 | return 0; |
989 | } |
990 | |
991 | nbytes = min_t(size_t, nbytes, FUSE_MAX_PAGES_PER_REQ << PAGE_SHIFT); |
992 | npages = (nbytes + offset + PAGE_SIZE - 1) >> PAGE_SHIFT; |
993 | npages = clamp(npages, 1, FUSE_MAX_PAGES_PER_REQ); |
994 | down_read(¤t->mm->mmap_sem); |
995 | npages = get_user_pages(current, current->mm, user_addr, npages, !write, |
996 | 0, req->pages, NULL); |
997 | up_read(¤t->mm->mmap_sem); |
998 | if (npages < 0) |
999 | return npages; |
1000 | |
1001 | req->num_pages = npages; |
1002 | req->page_offset = offset; |
1003 | |
1004 | if (write) |
1005 | req->in.argpages = 1; |
1006 | else |
1007 | req->out.argpages = 1; |
1008 | |
1009 | nbytes = (req->num_pages << PAGE_SHIFT) - req->page_offset; |
1010 | *nbytesp = min(*nbytesp, nbytes); |
1011 | |
1012 | return 0; |
1013 | } |
1014 | |
1015 | ssize_t fuse_direct_io(struct file *file, const char __user *buf, |
1016 | size_t count, loff_t *ppos, int write) |
1017 | { |
1018 | struct fuse_file *ff = file->private_data; |
1019 | struct fuse_conn *fc = ff->fc; |
1020 | size_t nmax = write ? fc->max_write : fc->max_read; |
1021 | loff_t pos = *ppos; |
1022 | ssize_t res = 0; |
1023 | struct fuse_req *req; |
1024 | |
1025 | req = fuse_get_req(fc); |
1026 | if (IS_ERR(req)) |
1027 | return PTR_ERR(req); |
1028 | |
1029 | while (count) { |
1030 | size_t nres; |
1031 | fl_owner_t owner = current->files; |
1032 | size_t nbytes = min(count, nmax); |
1033 | int err = fuse_get_user_pages(req, buf, &nbytes, write); |
1034 | if (err) { |
1035 | res = err; |
1036 | break; |
1037 | } |
1038 | |
1039 | if (write) |
1040 | nres = fuse_send_write(req, file, pos, nbytes, owner); |
1041 | else |
1042 | nres = fuse_send_read(req, file, pos, nbytes, owner); |
1043 | |
1044 | fuse_release_user_pages(req, !write); |
1045 | if (req->out.h.error) { |
1046 | if (!res) |
1047 | res = req->out.h.error; |
1048 | break; |
1049 | } else if (nres > nbytes) { |
1050 | res = -EIO; |
1051 | break; |
1052 | } |
1053 | count -= nres; |
1054 | res += nres; |
1055 | pos += nres; |
1056 | buf += nres; |
1057 | if (nres != nbytes) |
1058 | break; |
1059 | if (count) { |
1060 | fuse_put_request(fc, req); |
1061 | req = fuse_get_req(fc); |
1062 | if (IS_ERR(req)) |
1063 | break; |
1064 | } |
1065 | } |
1066 | fuse_put_request(fc, req); |
1067 | if (res > 0) |
1068 | *ppos = pos; |
1069 | |
1070 | return res; |
1071 | } |
1072 | EXPORT_SYMBOL_GPL(fuse_direct_io); |
1073 | |
1074 | static ssize_t fuse_direct_read(struct file *file, char __user *buf, |
1075 | size_t count, loff_t *ppos) |
1076 | { |
1077 | ssize_t res; |
1078 | struct inode *inode = file->f_path.dentry->d_inode; |
1079 | |
1080 | if (is_bad_inode(inode)) |
1081 | return -EIO; |
1082 | |
1083 | res = fuse_direct_io(file, buf, count, ppos, 0); |
1084 | |
1085 | fuse_invalidate_attr(inode); |
1086 | |
1087 | return res; |
1088 | } |
1089 | |
1090 | static ssize_t fuse_direct_write(struct file *file, const char __user *buf, |
1091 | size_t count, loff_t *ppos) |
1092 | { |
1093 | struct inode *inode = file->f_path.dentry->d_inode; |
1094 | ssize_t res; |
1095 | |
1096 | if (is_bad_inode(inode)) |
1097 | return -EIO; |
1098 | |
1099 | /* Don't allow parallel writes to the same file */ |
1100 | mutex_lock(&inode->i_mutex); |
1101 | res = generic_write_checks(file, ppos, &count, 0); |
1102 | if (!res) { |
1103 | res = fuse_direct_io(file, buf, count, ppos, 1); |
1104 | if (res > 0) |
1105 | fuse_write_update_size(inode, *ppos); |
1106 | } |
1107 | mutex_unlock(&inode->i_mutex); |
1108 | |
1109 | fuse_invalidate_attr(inode); |
1110 | |
1111 | return res; |
1112 | } |
1113 | |
1114 | static void fuse_writepage_free(struct fuse_conn *fc, struct fuse_req *req) |
1115 | { |
1116 | __free_page(req->pages[0]); |
1117 | fuse_file_put(req->ff); |
1118 | } |
1119 | |
1120 | static void fuse_writepage_finish(struct fuse_conn *fc, struct fuse_req *req) |
1121 | { |
1122 | struct inode *inode = req->inode; |
1123 | struct fuse_inode *fi = get_fuse_inode(inode); |
1124 | struct backing_dev_info *bdi = inode->i_mapping->backing_dev_info; |
1125 | |
1126 | list_del(&req->writepages_entry); |
1127 | dec_bdi_stat(bdi, BDI_WRITEBACK); |
1128 | dec_zone_page_state(req->pages[0], NR_WRITEBACK_TEMP); |
1129 | bdi_writeout_inc(bdi); |
1130 | wake_up(&fi->page_waitq); |
1131 | } |
1132 | |
1133 | /* Called under fc->lock, may release and reacquire it */ |
1134 | static void fuse_send_writepage(struct fuse_conn *fc, struct fuse_req *req) |
1135 | __releases(&fc->lock) |
1136 | __acquires(&fc->lock) |
1137 | { |
1138 | struct fuse_inode *fi = get_fuse_inode(req->inode); |
1139 | loff_t size = i_size_read(req->inode); |
1140 | struct fuse_write_in *inarg = &req->misc.write.in; |
1141 | |
1142 | if (!fc->connected) |
1143 | goto out_free; |
1144 | |
1145 | if (inarg->offset + PAGE_CACHE_SIZE <= size) { |
1146 | inarg->size = PAGE_CACHE_SIZE; |
1147 | } else if (inarg->offset < size) { |
1148 | inarg->size = size & (PAGE_CACHE_SIZE - 1); |
1149 | } else { |
1150 | /* Got truncated off completely */ |
1151 | goto out_free; |
1152 | } |
1153 | |
1154 | req->in.args[1].size = inarg->size; |
1155 | fi->writectr++; |
1156 | fuse_request_send_background_locked(fc, req); |
1157 | return; |
1158 | |
1159 | out_free: |
1160 | fuse_writepage_finish(fc, req); |
1161 | spin_unlock(&fc->lock); |
1162 | fuse_writepage_free(fc, req); |
1163 | fuse_put_request(fc, req); |
1164 | spin_lock(&fc->lock); |
1165 | } |
1166 | |
1167 | /* |
1168 | * If fi->writectr is positive (no truncate or fsync going on) send |
1169 | * all queued writepage requests. |
1170 | * |
1171 | * Called with fc->lock |
1172 | */ |
1173 | void fuse_flush_writepages(struct inode *inode) |
1174 | __releases(&fc->lock) |
1175 | __acquires(&fc->lock) |
1176 | { |
1177 | struct fuse_conn *fc = get_fuse_conn(inode); |
1178 | struct fuse_inode *fi = get_fuse_inode(inode); |
1179 | struct fuse_req *req; |
1180 | |
1181 | while (fi->writectr >= 0 && !list_empty(&fi->queued_writes)) { |
1182 | req = list_entry(fi->queued_writes.next, struct fuse_req, list); |
1183 | list_del_init(&req->list); |
1184 | fuse_send_writepage(fc, req); |
1185 | } |
1186 | } |
1187 | |
1188 | static void fuse_writepage_end(struct fuse_conn *fc, struct fuse_req *req) |
1189 | { |
1190 | struct inode *inode = req->inode; |
1191 | struct fuse_inode *fi = get_fuse_inode(inode); |
1192 | |
1193 | mapping_set_error(inode->i_mapping, req->out.h.error); |
1194 | spin_lock(&fc->lock); |
1195 | fi->writectr--; |
1196 | fuse_writepage_finish(fc, req); |
1197 | spin_unlock(&fc->lock); |
1198 | fuse_writepage_free(fc, req); |
1199 | } |
1200 | |
1201 | static int fuse_writepage_locked(struct page *page) |
1202 | { |
1203 | struct address_space *mapping = page->mapping; |
1204 | struct inode *inode = mapping->host; |
1205 | struct fuse_conn *fc = get_fuse_conn(inode); |
1206 | struct fuse_inode *fi = get_fuse_inode(inode); |
1207 | struct fuse_req *req; |
1208 | struct fuse_file *ff; |
1209 | struct page *tmp_page; |
1210 | |
1211 | set_page_writeback(page); |
1212 | |
1213 | req = fuse_request_alloc_nofs(); |
1214 | if (!req) |
1215 | goto err; |
1216 | |
1217 | tmp_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM); |
1218 | if (!tmp_page) |
1219 | goto err_free; |
1220 | |
1221 | spin_lock(&fc->lock); |
1222 | BUG_ON(list_empty(&fi->write_files)); |
1223 | ff = list_entry(fi->write_files.next, struct fuse_file, write_entry); |
1224 | req->ff = fuse_file_get(ff); |
1225 | spin_unlock(&fc->lock); |
1226 | |
1227 | fuse_write_fill(req, ff, page_offset(page), 0); |
1228 | |
1229 | copy_highpage(tmp_page, page); |
1230 | req->misc.write.in.write_flags |= FUSE_WRITE_CACHE; |
1231 | req->in.argpages = 1; |
1232 | req->num_pages = 1; |
1233 | req->pages[0] = tmp_page; |
1234 | req->page_offset = 0; |
1235 | req->end = fuse_writepage_end; |
1236 | req->inode = inode; |
1237 | |
1238 | inc_bdi_stat(mapping->backing_dev_info, BDI_WRITEBACK); |
1239 | inc_zone_page_state(tmp_page, NR_WRITEBACK_TEMP); |
1240 | end_page_writeback(page); |
1241 | |
1242 | spin_lock(&fc->lock); |
1243 | list_add(&req->writepages_entry, &fi->writepages); |
1244 | list_add_tail(&req->list, &fi->queued_writes); |
1245 | fuse_flush_writepages(inode); |
1246 | spin_unlock(&fc->lock); |
1247 | |
1248 | return 0; |
1249 | |
1250 | err_free: |
1251 | fuse_request_free(req); |
1252 | err: |
1253 | end_page_writeback(page); |
1254 | return -ENOMEM; |
1255 | } |
1256 | |
1257 | static int fuse_writepage(struct page *page, struct writeback_control *wbc) |
1258 | { |
1259 | int err; |
1260 | |
1261 | err = fuse_writepage_locked(page); |
1262 | unlock_page(page); |
1263 | |
1264 | return err; |
1265 | } |
1266 | |
1267 | static int fuse_launder_page(struct page *page) |
1268 | { |
1269 | int err = 0; |
1270 | if (clear_page_dirty_for_io(page)) { |
1271 | struct inode *inode = page->mapping->host; |
1272 | err = fuse_writepage_locked(page); |
1273 | if (!err) |
1274 | fuse_wait_on_page_writeback(inode, page->index); |
1275 | } |
1276 | return err; |
1277 | } |
1278 | |
1279 | /* |
1280 | * Write back dirty pages now, because there may not be any suitable |
1281 | * open files later |
1282 | */ |
1283 | static void fuse_vma_close(struct vm_area_struct *vma) |
1284 | { |
1285 | filemap_write_and_wait(vma->vm_file->f_mapping); |
1286 | } |
1287 | |
1288 | /* |
1289 | * Wait for writeback against this page to complete before allowing it |
1290 | * to be marked dirty again, and hence written back again, possibly |
1291 | * before the previous writepage completed. |
1292 | * |
1293 | * Block here, instead of in ->writepage(), so that the userspace fs |
1294 | * can only block processes actually operating on the filesystem. |
1295 | * |
1296 | * Otherwise unprivileged userspace fs would be able to block |
1297 | * unrelated: |
1298 | * |
1299 | * - page migration |
1300 | * - sync(2) |
1301 | * - try_to_free_pages() with order > PAGE_ALLOC_COSTLY_ORDER |
1302 | */ |
1303 | static int fuse_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf) |
1304 | { |
1305 | struct page *page = vmf->page; |
1306 | /* |
1307 | * Don't use page->mapping as it may become NULL from a |
1308 | * concurrent truncate. |
1309 | */ |
1310 | struct inode *inode = vma->vm_file->f_mapping->host; |
1311 | |
1312 | fuse_wait_on_page_writeback(inode, page->index); |
1313 | return 0; |
1314 | } |
1315 | |
1316 | static struct vm_operations_struct fuse_file_vm_ops = { |
1317 | .close = fuse_vma_close, |
1318 | .fault = filemap_fault, |
1319 | .page_mkwrite = fuse_page_mkwrite, |
1320 | }; |
1321 | |
1322 | static int fuse_file_mmap(struct file *file, struct vm_area_struct *vma) |
1323 | { |
1324 | if ((vma->vm_flags & VM_SHARED) && (vma->vm_flags & VM_MAYWRITE)) { |
1325 | struct inode *inode = file->f_dentry->d_inode; |
1326 | struct fuse_conn *fc = get_fuse_conn(inode); |
1327 | struct fuse_inode *fi = get_fuse_inode(inode); |
1328 | struct fuse_file *ff = file->private_data; |
1329 | /* |
1330 | * file may be written through mmap, so chain it onto the |
1331 | * inodes's write_file list |
1332 | */ |
1333 | spin_lock(&fc->lock); |
1334 | if (list_empty(&ff->write_entry)) |
1335 | list_add(&ff->write_entry, &fi->write_files); |
1336 | spin_unlock(&fc->lock); |
1337 | } |
1338 | file_accessed(file); |
1339 | vma->vm_ops = &fuse_file_vm_ops; |
1340 | return 0; |
1341 | } |
1342 | |
1343 | static int fuse_direct_mmap(struct file *file, struct vm_area_struct *vma) |
1344 | { |
1345 | /* Can't provide the coherency needed for MAP_SHARED */ |
1346 | if (vma->vm_flags & VM_MAYSHARE) |
1347 | return -ENODEV; |
1348 | |
1349 | invalidate_inode_pages2(file->f_mapping); |
1350 | |
1351 | return generic_file_mmap(file, vma); |
1352 | } |
1353 | |
1354 | static int convert_fuse_file_lock(const struct fuse_file_lock *ffl, |
1355 | struct file_lock *fl) |
1356 | { |
1357 | switch (ffl->type) { |
1358 | case F_UNLCK: |
1359 | break; |
1360 | |
1361 | case F_RDLCK: |
1362 | case F_WRLCK: |
1363 | if (ffl->start > OFFSET_MAX || ffl->end > OFFSET_MAX || |
1364 | ffl->end < ffl->start) |
1365 | return -EIO; |
1366 | |
1367 | fl->fl_start = ffl->start; |
1368 | fl->fl_end = ffl->end; |
1369 | fl->fl_pid = ffl->pid; |
1370 | break; |
1371 | |
1372 | default: |
1373 | return -EIO; |
1374 | } |
1375 | fl->fl_type = ffl->type; |
1376 | return 0; |
1377 | } |
1378 | |
1379 | static void fuse_lk_fill(struct fuse_req *req, struct file *file, |
1380 | const struct file_lock *fl, int opcode, pid_t pid, |
1381 | int flock) |
1382 | { |
1383 | struct inode *inode = file->f_path.dentry->d_inode; |
1384 | struct fuse_conn *fc = get_fuse_conn(inode); |
1385 | struct fuse_file *ff = file->private_data; |
1386 | struct fuse_lk_in *arg = &req->misc.lk_in; |
1387 | |
1388 | arg->fh = ff->fh; |
1389 | arg->owner = fuse_lock_owner_id(fc, fl->fl_owner); |
1390 | arg->lk.start = fl->fl_start; |
1391 | arg->lk.end = fl->fl_end; |
1392 | arg->lk.type = fl->fl_type; |
1393 | arg->lk.pid = pid; |
1394 | if (flock) |
1395 | arg->lk_flags |= FUSE_LK_FLOCK; |
1396 | req->in.h.opcode = opcode; |
1397 | req->in.h.nodeid = get_node_id(inode); |
1398 | req->in.numargs = 1; |
1399 | req->in.args[0].size = sizeof(*arg); |
1400 | req->in.args[0].value = arg; |
1401 | } |
1402 | |
1403 | static int fuse_getlk(struct file *file, struct file_lock *fl) |
1404 | { |
1405 | struct inode *inode = file->f_path.dentry->d_inode; |
1406 | struct fuse_conn *fc = get_fuse_conn(inode); |
1407 | struct fuse_req *req; |
1408 | struct fuse_lk_out outarg; |
1409 | int err; |
1410 | |
1411 | req = fuse_get_req(fc); |
1412 | if (IS_ERR(req)) |
1413 | return PTR_ERR(req); |
1414 | |
1415 | fuse_lk_fill(req, file, fl, FUSE_GETLK, 0, 0); |
1416 | req->out.numargs = 1; |
1417 | req->out.args[0].size = sizeof(outarg); |
1418 | req->out.args[0].value = &outarg; |
1419 | fuse_request_send(fc, req); |
1420 | err = req->out.h.error; |
1421 | fuse_put_request(fc, req); |
1422 | if (!err) |
1423 | err = convert_fuse_file_lock(&outarg.lk, fl); |
1424 | |
1425 | return err; |
1426 | } |
1427 | |
1428 | static int fuse_setlk(struct file *file, struct file_lock *fl, int flock) |
1429 | { |
1430 | struct inode *inode = file->f_path.dentry->d_inode; |
1431 | struct fuse_conn *fc = get_fuse_conn(inode); |
1432 | struct fuse_req *req; |
1433 | int opcode = (fl->fl_flags & FL_SLEEP) ? FUSE_SETLKW : FUSE_SETLK; |
1434 | pid_t pid = fl->fl_type != F_UNLCK ? current->tgid : 0; |
1435 | int err; |
1436 | |
1437 | if (fl->fl_lmops && fl->fl_lmops->fl_grant) { |
1438 | /* NLM needs asynchronous locks, which we don't support yet */ |
1439 | return -ENOLCK; |
1440 | } |
1441 | |
1442 | /* Unlock on close is handled by the flush method */ |
1443 | if (fl->fl_flags & FL_CLOSE) |
1444 | return 0; |
1445 | |
1446 | req = fuse_get_req(fc); |
1447 | if (IS_ERR(req)) |
1448 | return PTR_ERR(req); |
1449 | |
1450 | fuse_lk_fill(req, file, fl, opcode, pid, flock); |
1451 | fuse_request_send(fc, req); |
1452 | err = req->out.h.error; |
1453 | /* locking is restartable */ |
1454 | if (err == -EINTR) |
1455 | err = -ERESTARTSYS; |
1456 | fuse_put_request(fc, req); |
1457 | return err; |
1458 | } |
1459 | |
1460 | static int fuse_file_lock(struct file *file, int cmd, struct file_lock *fl) |
1461 | { |
1462 | struct inode *inode = file->f_path.dentry->d_inode; |
1463 | struct fuse_conn *fc = get_fuse_conn(inode); |
1464 | int err; |
1465 | |
1466 | if (cmd == F_CANCELLK) { |
1467 | err = 0; |
1468 | } else if (cmd == F_GETLK) { |
1469 | if (fc->no_lock) { |
1470 | posix_test_lock(file, fl); |
1471 | err = 0; |
1472 | } else |
1473 | err = fuse_getlk(file, fl); |
1474 | } else { |
1475 | if (fc->no_lock) |
1476 | err = posix_lock_file(file, fl, NULL); |
1477 | else |
1478 | err = fuse_setlk(file, fl, 0); |
1479 | } |
1480 | return err; |
1481 | } |
1482 | |
1483 | static int fuse_file_flock(struct file *file, int cmd, struct file_lock *fl) |
1484 | { |
1485 | struct inode *inode = file->f_path.dentry->d_inode; |
1486 | struct fuse_conn *fc = get_fuse_conn(inode); |
1487 | int err; |
1488 | |
1489 | if (fc->no_lock) { |
1490 | err = flock_lock_file_wait(file, fl); |
1491 | } else { |
1492 | /* emulate flock with POSIX locks */ |
1493 | fl->fl_owner = (fl_owner_t) file; |
1494 | err = fuse_setlk(file, fl, 1); |
1495 | } |
1496 | |
1497 | return err; |
1498 | } |
1499 | |
1500 | static sector_t fuse_bmap(struct address_space *mapping, sector_t block) |
1501 | { |
1502 | struct inode *inode = mapping->host; |
1503 | struct fuse_conn *fc = get_fuse_conn(inode); |
1504 | struct fuse_req *req; |
1505 | struct fuse_bmap_in inarg; |
1506 | struct fuse_bmap_out outarg; |
1507 | int err; |
1508 | |
1509 | if (!inode->i_sb->s_bdev || fc->no_bmap) |
1510 | return 0; |
1511 | |
1512 | req = fuse_get_req(fc); |
1513 | if (IS_ERR(req)) |
1514 | return 0; |
1515 | |
1516 | memset(&inarg, 0, sizeof(inarg)); |
1517 | inarg.block = block; |
1518 | inarg.blocksize = inode->i_sb->s_blocksize; |
1519 | req->in.h.opcode = FUSE_BMAP; |
1520 | req->in.h.nodeid = get_node_id(inode); |
1521 | req->in.numargs = 1; |
1522 | req->in.args[0].size = sizeof(inarg); |
1523 | req->in.args[0].value = &inarg; |
1524 | req->out.numargs = 1; |
1525 | req->out.args[0].size = sizeof(outarg); |
1526 | req->out.args[0].value = &outarg; |
1527 | fuse_request_send(fc, req); |
1528 | err = req->out.h.error; |
1529 | fuse_put_request(fc, req); |
1530 | if (err == -ENOSYS) |
1531 | fc->no_bmap = 1; |
1532 | |
1533 | return err ? 0 : outarg.block; |
1534 | } |
1535 | |
1536 | static loff_t fuse_file_llseek(struct file *file, loff_t offset, int origin) |
1537 | { |
1538 | loff_t retval; |
1539 | struct inode *inode = file->f_path.dentry->d_inode; |
1540 | |
1541 | mutex_lock(&inode->i_mutex); |
1542 | switch (origin) { |
1543 | case SEEK_END: |
1544 | retval = fuse_update_attributes(inode, NULL, file, NULL); |
1545 | if (retval) |
1546 | goto exit; |
1547 | offset += i_size_read(inode); |
1548 | break; |
1549 | case SEEK_CUR: |
1550 | offset += file->f_pos; |
1551 | } |
1552 | retval = -EINVAL; |
1553 | if (offset >= 0 && offset <= inode->i_sb->s_maxbytes) { |
1554 | if (offset != file->f_pos) { |
1555 | file->f_pos = offset; |
1556 | file->f_version = 0; |
1557 | } |
1558 | retval = offset; |
1559 | } |
1560 | exit: |
1561 | mutex_unlock(&inode->i_mutex); |
1562 | return retval; |
1563 | } |
1564 | |
1565 | static int fuse_ioctl_copy_user(struct page **pages, struct iovec *iov, |
1566 | unsigned int nr_segs, size_t bytes, bool to_user) |
1567 | { |
1568 | struct iov_iter ii; |
1569 | int page_idx = 0; |
1570 | |
1571 | if (!bytes) |
1572 | return 0; |
1573 | |
1574 | iov_iter_init(&ii, iov, nr_segs, bytes, 0); |
1575 | |
1576 | while (iov_iter_count(&ii)) { |
1577 | struct page *page = pages[page_idx++]; |
1578 | size_t todo = min_t(size_t, PAGE_SIZE, iov_iter_count(&ii)); |
1579 | void *kaddr, *map; |
1580 | |
1581 | kaddr = map = kmap(page); |
1582 | |
1583 | while (todo) { |
1584 | char __user *uaddr = ii.iov->iov_base + ii.iov_offset; |
1585 | size_t iov_len = ii.iov->iov_len - ii.iov_offset; |
1586 | size_t copy = min(todo, iov_len); |
1587 | size_t left; |
1588 | |
1589 | if (!to_user) |
1590 | left = copy_from_user(kaddr, uaddr, copy); |
1591 | else |
1592 | left = copy_to_user(uaddr, kaddr, copy); |
1593 | |
1594 | if (unlikely(left)) |
1595 | return -EFAULT; |
1596 | |
1597 | iov_iter_advance(&ii, copy); |
1598 | todo -= copy; |
1599 | kaddr += copy; |
1600 | } |
1601 | |
1602 | kunmap(map); |
1603 | } |
1604 | |
1605 | return 0; |
1606 | } |
1607 | |
1608 | /* |
1609 | * For ioctls, there is no generic way to determine how much memory |
1610 | * needs to be read and/or written. Furthermore, ioctls are allowed |
1611 | * to dereference the passed pointer, so the parameter requires deep |
1612 | * copying but FUSE has no idea whatsoever about what to copy in or |
1613 | * out. |
1614 | * |
1615 | * This is solved by allowing FUSE server to retry ioctl with |
1616 | * necessary in/out iovecs. Let's assume the ioctl implementation |
1617 | * needs to read in the following structure. |
1618 | * |
1619 | * struct a { |
1620 | * char *buf; |
1621 | * size_t buflen; |
1622 | * } |
1623 | * |
1624 | * On the first callout to FUSE server, inarg->in_size and |
1625 | * inarg->out_size will be NULL; then, the server completes the ioctl |
1626 | * with FUSE_IOCTL_RETRY set in out->flags, out->in_iovs set to 1 and |
1627 | * the actual iov array to |
1628 | * |
1629 | * { { .iov_base = inarg.arg, .iov_len = sizeof(struct a) } } |
1630 | * |
1631 | * which tells FUSE to copy in the requested area and retry the ioctl. |
1632 | * On the second round, the server has access to the structure and |
1633 | * from that it can tell what to look for next, so on the invocation, |
1634 | * it sets FUSE_IOCTL_RETRY, out->in_iovs to 2 and iov array to |
1635 | * |
1636 | * { { .iov_base = inarg.arg, .iov_len = sizeof(struct a) }, |
1637 | * { .iov_base = a.buf, .iov_len = a.buflen } } |
1638 | * |
1639 | * FUSE will copy both struct a and the pointed buffer from the |
1640 | * process doing the ioctl and retry ioctl with both struct a and the |
1641 | * buffer. |
1642 | * |
1643 | * This time, FUSE server has everything it needs and completes ioctl |
1644 | * without FUSE_IOCTL_RETRY which finishes the ioctl call. |
1645 | * |
1646 | * Copying data out works the same way. |
1647 | * |
1648 | * Note that if FUSE_IOCTL_UNRESTRICTED is clear, the kernel |
1649 | * automatically initializes in and out iovs by decoding @cmd with |
1650 | * _IOC_* macros and the server is not allowed to request RETRY. This |
1651 | * limits ioctl data transfers to well-formed ioctls and is the forced |
1652 | * behavior for all FUSE servers. |
1653 | */ |
1654 | long fuse_do_ioctl(struct file *file, unsigned int cmd, unsigned long arg, |
1655 | unsigned int flags) |
1656 | { |
1657 | struct fuse_file *ff = file->private_data; |
1658 | struct fuse_conn *fc = ff->fc; |
1659 | struct fuse_ioctl_in inarg = { |
1660 | .fh = ff->fh, |
1661 | .cmd = cmd, |
1662 | .arg = arg, |
1663 | .flags = flags |
1664 | }; |
1665 | struct fuse_ioctl_out outarg; |
1666 | struct fuse_req *req = NULL; |
1667 | struct page **pages = NULL; |
1668 | struct page *iov_page = NULL; |
1669 | struct iovec *in_iov = NULL, *out_iov = NULL; |
1670 | unsigned int in_iovs = 0, out_iovs = 0, num_pages = 0, max_pages; |
1671 | size_t in_size, out_size, transferred; |
1672 | int err; |
1673 | |
1674 | /* assume all the iovs returned by client always fits in a page */ |
1675 | BUILD_BUG_ON(sizeof(struct iovec) * FUSE_IOCTL_MAX_IOV > PAGE_SIZE); |
1676 | |
1677 | err = -ENOMEM; |
1678 | pages = kzalloc(sizeof(pages[0]) * FUSE_MAX_PAGES_PER_REQ, GFP_KERNEL); |
1679 | iov_page = alloc_page(GFP_KERNEL); |
1680 | if (!pages || !iov_page) |
1681 | goto out; |
1682 | |
1683 | /* |
1684 | * If restricted, initialize IO parameters as encoded in @cmd. |
1685 | * RETRY from server is not allowed. |
1686 | */ |
1687 | if (!(flags & FUSE_IOCTL_UNRESTRICTED)) { |
1688 | struct iovec *iov = page_address(iov_page); |
1689 | |
1690 | iov->iov_base = (void __user *)arg; |
1691 | iov->iov_len = _IOC_SIZE(cmd); |
1692 | |
1693 | if (_IOC_DIR(cmd) & _IOC_WRITE) { |
1694 | in_iov = iov; |
1695 | in_iovs = 1; |
1696 | } |
1697 | |
1698 | if (_IOC_DIR(cmd) & _IOC_READ) { |
1699 | out_iov = iov; |
1700 | out_iovs = 1; |
1701 | } |
1702 | } |
1703 | |
1704 | retry: |
1705 | inarg.in_size = in_size = iov_length(in_iov, in_iovs); |
1706 | inarg.out_size = out_size = iov_length(out_iov, out_iovs); |
1707 | |
1708 | /* |
1709 | * Out data can be used either for actual out data or iovs, |
1710 | * make sure there always is at least one page. |
1711 | */ |
1712 | out_size = max_t(size_t, out_size, PAGE_SIZE); |
1713 | max_pages = DIV_ROUND_UP(max(in_size, out_size), PAGE_SIZE); |
1714 | |
1715 | /* make sure there are enough buffer pages and init request with them */ |
1716 | err = -ENOMEM; |
1717 | if (max_pages > FUSE_MAX_PAGES_PER_REQ) |
1718 | goto out; |
1719 | while (num_pages < max_pages) { |
1720 | pages[num_pages] = alloc_page(GFP_KERNEL | __GFP_HIGHMEM); |
1721 | if (!pages[num_pages]) |
1722 | goto out; |
1723 | num_pages++; |
1724 | } |
1725 | |
1726 | req = fuse_get_req(fc); |
1727 | if (IS_ERR(req)) { |
1728 | err = PTR_ERR(req); |
1729 | req = NULL; |
1730 | goto out; |
1731 | } |
1732 | memcpy(req->pages, pages, sizeof(req->pages[0]) * num_pages); |
1733 | req->num_pages = num_pages; |
1734 | |
1735 | /* okay, let's send it to the client */ |
1736 | req->in.h.opcode = FUSE_IOCTL; |
1737 | req->in.h.nodeid = ff->nodeid; |
1738 | req->in.numargs = 1; |
1739 | req->in.args[0].size = sizeof(inarg); |
1740 | req->in.args[0].value = &inarg; |
1741 | if (in_size) { |
1742 | req->in.numargs++; |
1743 | req->in.args[1].size = in_size; |
1744 | req->in.argpages = 1; |
1745 | |
1746 | err = fuse_ioctl_copy_user(pages, in_iov, in_iovs, in_size, |
1747 | false); |
1748 | if (err) |
1749 | goto out; |
1750 | } |
1751 | |
1752 | req->out.numargs = 2; |
1753 | req->out.args[0].size = sizeof(outarg); |
1754 | req->out.args[0].value = &outarg; |
1755 | req->out.args[1].size = out_size; |
1756 | req->out.argpages = 1; |
1757 | req->out.argvar = 1; |
1758 | |
1759 | fuse_request_send(fc, req); |
1760 | err = req->out.h.error; |
1761 | transferred = req->out.args[1].size; |
1762 | fuse_put_request(fc, req); |
1763 | req = NULL; |
1764 | if (err) |
1765 | goto out; |
1766 | |
1767 | /* did it ask for retry? */ |
1768 | if (outarg.flags & FUSE_IOCTL_RETRY) { |
1769 | char *vaddr; |
1770 | |
1771 | /* no retry if in restricted mode */ |
1772 | err = -EIO; |
1773 | if (!(flags & FUSE_IOCTL_UNRESTRICTED)) |
1774 | goto out; |
1775 | |
1776 | in_iovs = outarg.in_iovs; |
1777 | out_iovs = outarg.out_iovs; |
1778 | |
1779 | /* |
1780 | * Make sure things are in boundary, separate checks |
1781 | * are to protect against overflow. |
1782 | */ |
1783 | err = -ENOMEM; |
1784 | if (in_iovs > FUSE_IOCTL_MAX_IOV || |
1785 | out_iovs > FUSE_IOCTL_MAX_IOV || |
1786 | in_iovs + out_iovs > FUSE_IOCTL_MAX_IOV) |
1787 | goto out; |
1788 | |
1789 | err = -EIO; |
1790 | if ((in_iovs + out_iovs) * sizeof(struct iovec) != transferred) |
1791 | goto out; |
1792 | |
1793 | /* okay, copy in iovs and retry */ |
1794 | vaddr = kmap_atomic(pages[0], KM_USER0); |
1795 | memcpy(page_address(iov_page), vaddr, transferred); |
1796 | kunmap_atomic(vaddr, KM_USER0); |
1797 | |
1798 | in_iov = page_address(iov_page); |
1799 | out_iov = in_iov + in_iovs; |
1800 | |
1801 | goto retry; |
1802 | } |
1803 | |
1804 | err = -EIO; |
1805 | if (transferred > inarg.out_size) |
1806 | goto out; |
1807 | |
1808 | err = fuse_ioctl_copy_user(pages, out_iov, out_iovs, transferred, true); |
1809 | out: |
1810 | if (req) |
1811 | fuse_put_request(fc, req); |
1812 | if (iov_page) |
1813 | __free_page(iov_page); |
1814 | while (num_pages) |
1815 | __free_page(pages[--num_pages]); |
1816 | kfree(pages); |
1817 | |
1818 | return err ? err : outarg.result; |
1819 | } |
1820 | EXPORT_SYMBOL_GPL(fuse_do_ioctl); |
1821 | |
1822 | static long fuse_file_ioctl_common(struct file *file, unsigned int cmd, |
1823 | unsigned long arg, unsigned int flags) |
1824 | { |
1825 | struct inode *inode = file->f_dentry->d_inode; |
1826 | struct fuse_conn *fc = get_fuse_conn(inode); |
1827 | |
1828 | if (!fuse_allow_task(fc, current)) |
1829 | return -EACCES; |
1830 | |
1831 | if (is_bad_inode(inode)) |
1832 | return -EIO; |
1833 | |
1834 | return fuse_do_ioctl(file, cmd, arg, flags); |
1835 | } |
1836 | |
1837 | static long fuse_file_ioctl(struct file *file, unsigned int cmd, |
1838 | unsigned long arg) |
1839 | { |
1840 | return fuse_file_ioctl_common(file, cmd, arg, 0); |
1841 | } |
1842 | |
1843 | static long fuse_file_compat_ioctl(struct file *file, unsigned int cmd, |
1844 | unsigned long arg) |
1845 | { |
1846 | return fuse_file_ioctl_common(file, cmd, arg, FUSE_IOCTL_COMPAT); |
1847 | } |
1848 | |
1849 | /* |
1850 | * All files which have been polled are linked to RB tree |
1851 | * fuse_conn->polled_files which is indexed by kh. Walk the tree and |
1852 | * find the matching one. |
1853 | */ |
1854 | static struct rb_node **fuse_find_polled_node(struct fuse_conn *fc, u64 kh, |
1855 | struct rb_node **parent_out) |
1856 | { |
1857 | struct rb_node **link = &fc->polled_files.rb_node; |
1858 | struct rb_node *last = NULL; |
1859 | |
1860 | while (*link) { |
1861 | struct fuse_file *ff; |
1862 | |
1863 | last = *link; |
1864 | ff = rb_entry(last, struct fuse_file, polled_node); |
1865 | |
1866 | if (kh < ff->kh) |
1867 | link = &last->rb_left; |
1868 | else if (kh > ff->kh) |
1869 | link = &last->rb_right; |
1870 | else |
1871 | return link; |
1872 | } |
1873 | |
1874 | if (parent_out) |
1875 | *parent_out = last; |
1876 | return link; |
1877 | } |
1878 | |
1879 | /* |
1880 | * The file is about to be polled. Make sure it's on the polled_files |
1881 | * RB tree. Note that files once added to the polled_files tree are |
1882 | * not removed before the file is released. This is because a file |
1883 | * polled once is likely to be polled again. |
1884 | */ |
1885 | static void fuse_register_polled_file(struct fuse_conn *fc, |
1886 | struct fuse_file *ff) |
1887 | { |
1888 | spin_lock(&fc->lock); |
1889 | if (RB_EMPTY_NODE(&ff->polled_node)) { |
1890 | struct rb_node **link, *parent; |
1891 | |
1892 | link = fuse_find_polled_node(fc, ff->kh, &parent); |
1893 | BUG_ON(*link); |
1894 | rb_link_node(&ff->polled_node, parent, link); |
1895 | rb_insert_color(&ff->polled_node, &fc->polled_files); |
1896 | } |
1897 | spin_unlock(&fc->lock); |
1898 | } |
1899 | |
1900 | unsigned fuse_file_poll(struct file *file, poll_table *wait) |
1901 | { |
1902 | struct fuse_file *ff = file->private_data; |
1903 | struct fuse_conn *fc = ff->fc; |
1904 | struct fuse_poll_in inarg = { .fh = ff->fh, .kh = ff->kh }; |
1905 | struct fuse_poll_out outarg; |
1906 | struct fuse_req *req; |
1907 | int err; |
1908 | |
1909 | if (fc->no_poll) |
1910 | return DEFAULT_POLLMASK; |
1911 | |
1912 | poll_wait(file, &ff->poll_wait, wait); |
1913 | |
1914 | /* |
1915 | * Ask for notification iff there's someone waiting for it. |
1916 | * The client may ignore the flag and always notify. |
1917 | */ |
1918 | if (waitqueue_active(&ff->poll_wait)) { |
1919 | inarg.flags |= FUSE_POLL_SCHEDULE_NOTIFY; |
1920 | fuse_register_polled_file(fc, ff); |
1921 | } |
1922 | |
1923 | req = fuse_get_req(fc); |
1924 | if (IS_ERR(req)) |
1925 | return POLLERR; |
1926 | |
1927 | req->in.h.opcode = FUSE_POLL; |
1928 | req->in.h.nodeid = ff->nodeid; |
1929 | req->in.numargs = 1; |
1930 | req->in.args[0].size = sizeof(inarg); |
1931 | req->in.args[0].value = &inarg; |
1932 | req->out.numargs = 1; |
1933 | req->out.args[0].size = sizeof(outarg); |
1934 | req->out.args[0].value = &outarg; |
1935 | fuse_request_send(fc, req); |
1936 | err = req->out.h.error; |
1937 | fuse_put_request(fc, req); |
1938 | |
1939 | if (!err) |
1940 | return outarg.revents; |
1941 | if (err == -ENOSYS) { |
1942 | fc->no_poll = 1; |
1943 | return DEFAULT_POLLMASK; |
1944 | } |
1945 | return POLLERR; |
1946 | } |
1947 | EXPORT_SYMBOL_GPL(fuse_file_poll); |
1948 | |
1949 | /* |
1950 | * This is called from fuse_handle_notify() on FUSE_NOTIFY_POLL and |
1951 | * wakes up the poll waiters. |
1952 | */ |
1953 | int fuse_notify_poll_wakeup(struct fuse_conn *fc, |
1954 | struct fuse_notify_poll_wakeup_out *outarg) |
1955 | { |
1956 | u64 kh = outarg->kh; |
1957 | struct rb_node **link; |
1958 | |
1959 | spin_lock(&fc->lock); |
1960 | |
1961 | link = fuse_find_polled_node(fc, kh, NULL); |
1962 | if (*link) { |
1963 | struct fuse_file *ff; |
1964 | |
1965 | ff = rb_entry(*link, struct fuse_file, polled_node); |
1966 | wake_up_interruptible_sync(&ff->poll_wait); |
1967 | } |
1968 | |
1969 | spin_unlock(&fc->lock); |
1970 | return 0; |
1971 | } |
1972 | |
1973 | static const struct file_operations fuse_file_operations = { |
1974 | .llseek = fuse_file_llseek, |
1975 | .read = do_sync_read, |
1976 | .aio_read = fuse_file_aio_read, |
1977 | .write = do_sync_write, |
1978 | .aio_write = fuse_file_aio_write, |
1979 | .mmap = fuse_file_mmap, |
1980 | .open = fuse_open, |
1981 | .flush = fuse_flush, |
1982 | .release = fuse_release, |
1983 | .fsync = fuse_fsync, |
1984 | .lock = fuse_file_lock, |
1985 | .flock = fuse_file_flock, |
1986 | .splice_read = generic_file_splice_read, |
1987 | .unlocked_ioctl = fuse_file_ioctl, |
1988 | .compat_ioctl = fuse_file_compat_ioctl, |
1989 | .poll = fuse_file_poll, |
1990 | }; |
1991 | |
1992 | static const struct file_operations fuse_direct_io_file_operations = { |
1993 | .llseek = fuse_file_llseek, |
1994 | .read = fuse_direct_read, |
1995 | .write = fuse_direct_write, |
1996 | .mmap = fuse_direct_mmap, |
1997 | .open = fuse_open, |
1998 | .flush = fuse_flush, |
1999 | .release = fuse_release, |
2000 | .fsync = fuse_fsync, |
2001 | .lock = fuse_file_lock, |
2002 | .flock = fuse_file_flock, |
2003 | .unlocked_ioctl = fuse_file_ioctl, |
2004 | .compat_ioctl = fuse_file_compat_ioctl, |
2005 | .poll = fuse_file_poll, |
2006 | /* no splice_read */ |
2007 | }; |
2008 | |
2009 | static const struct address_space_operations fuse_file_aops = { |
2010 | .readpage = fuse_readpage, |
2011 | .writepage = fuse_writepage, |
2012 | .launder_page = fuse_launder_page, |
2013 | .write_begin = fuse_write_begin, |
2014 | .write_end = fuse_write_end, |
2015 | .readpages = fuse_readpages, |
2016 | .set_page_dirty = __set_page_dirty_nobuffers, |
2017 | .bmap = fuse_bmap, |
2018 | }; |
2019 | |
2020 | void fuse_init_file_inode(struct inode *inode) |
2021 | { |
2022 | inode->i_fop = &fuse_file_operations; |
2023 | inode->i_data.a_ops = &fuse_file_aops; |
2024 | } |
2025 |
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