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