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x86, gdt, hibernate: Store/load GDT for hibernate path.
[linux-2.6/btrfs-unstable.git] / fs / fuse / file.c
blobd15c6f21c17f6eefe1d90f16e77d59afe045394b
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 #include <linux/compat.h>
17 #include <linux/swap.h>
18
19 static const struct file_operations fuse_direct_io_file_operations;
20
21 static int fuse_send_open(struct fuse_conn *fc, u64 nodeid, struct file *file,
22 int opcode, struct fuse_open_out *outargp)
23 {
24 struct fuse_open_in inarg;
25 struct fuse_req *req;
26 int err;
27
28 req = fuse_get_req_nopages(fc);
29 if (IS_ERR(req))
30 return PTR_ERR(req);
31
32 memset(&inarg, 0, sizeof(inarg));
33 inarg.flags = file->f_flags & ~(O_CREAT | O_EXCL | O_NOCTTY);
34 if (!fc->atomic_o_trunc)
35 inarg.flags &= ~O_TRUNC;
36 req->in.h.opcode = opcode;
37 req->in.h.nodeid = nodeid;
38 req->in.numargs = 1;
39 req->in.args[0].size = sizeof(inarg);
40 req->in.args[0].value = &inarg;
41 req->out.numargs = 1;
42 req->out.args[0].size = sizeof(*outargp);
43 req->out.args[0].value = outargp;
44 fuse_request_send(fc, req);
45 err = req->out.h.error;
46 fuse_put_request(fc, req);
47
48 return err;
49 }
50
51 struct fuse_file *fuse_file_alloc(struct fuse_conn *fc)
52 {
53 struct fuse_file *ff;
54
55 ff = kmalloc(sizeof(struct fuse_file), GFP_KERNEL);
56 if (unlikely(!ff))
57 return NULL;
58
59 ff->fc = fc;
60 ff->reserved_req = fuse_request_alloc(0);
61 if (unlikely(!ff->reserved_req)) {
62 kfree(ff);
63 return NULL;
64 }
65
66 INIT_LIST_HEAD(&ff->write_entry);
67 atomic_set(&ff->count, 0);
68 RB_CLEAR_NODE(&ff->polled_node);
69 init_waitqueue_head(&ff->poll_wait);
70
71 spin_lock(&fc->lock);
72 ff->kh = ++fc->khctr;
73 spin_unlock(&fc->lock);
74
75 return ff;
76 }
77
78 void fuse_file_free(struct fuse_file *ff)
79 {
80 fuse_request_free(ff->reserved_req);
81 kfree(ff);
82 }
83
84 struct fuse_file *fuse_file_get(struct fuse_file *ff)
85 {
86 atomic_inc(&ff->count);
87 return ff;
88 }
89
90 static void fuse_release_async(struct work_struct *work)
91 {
92 struct fuse_req *req;
93 struct fuse_conn *fc;
94 struct path path;
95
96 req = container_of(work, struct fuse_req, misc.release.work);
97 path = req->misc.release.path;
98 fc = get_fuse_conn(path.dentry->d_inode);
99
100 fuse_put_request(fc, req);
101 path_put(&path);
102 }
103
104 static void fuse_release_end(struct fuse_conn *fc, struct fuse_req *req)
105 {
106 if (fc->destroy_req) {
107 /*
108 * If this is a fuseblk mount, then it's possible that
109 * releasing the path will result in releasing the
110 * super block and sending the DESTROY request. If
111 * the server is single threaded, this would hang.
112 * For this reason do the path_put() in a separate
113 * thread.
114 */
115 atomic_inc(&req->count);
116 INIT_WORK(&req->misc.release.work, fuse_release_async);
117 schedule_work(&req->misc.release.work);
118 } else {
119 path_put(&req->misc.release.path);
120 }
121 }
122
123 static void fuse_file_put(struct fuse_file *ff, bool sync)
124 {
125 if (atomic_dec_and_test(&ff->count)) {
126 struct fuse_req *req = ff->reserved_req;
127
128 if (sync) {
129 fuse_request_send(ff->fc, req);
130 path_put(&req->misc.release.path);
131 fuse_put_request(ff->fc, req);
132 } else {
133 req->end = fuse_release_end;
134 fuse_request_send_background(ff->fc, req);
135 }
136 kfree(ff);
137 }
138 }
139
140 int fuse_do_open(struct fuse_conn *fc, u64 nodeid, struct file *file,
141 bool isdir)
142 {
143 struct fuse_open_out outarg;
144 struct fuse_file *ff;
145 int err;
146 int opcode = isdir ? FUSE_OPENDIR : FUSE_OPEN;
147
148 ff = fuse_file_alloc(fc);
149 if (!ff)
150 return -ENOMEM;
151
152 err = fuse_send_open(fc, nodeid, file, opcode, &outarg);
153 if (err) {
154 fuse_file_free(ff);
155 return err;
156 }
157
158 if (isdir)
159 outarg.open_flags &= ~FOPEN_DIRECT_IO;
160
161 ff->fh = outarg.fh;
162 ff->nodeid = nodeid;
163 ff->open_flags = outarg.open_flags;
164 file->private_data = fuse_file_get(ff);
165
166 return 0;
167 }
168 EXPORT_SYMBOL_GPL(fuse_do_open);
169
170 void fuse_finish_open(struct inode *inode, struct file *file)
171 {
172 struct fuse_file *ff = file->private_data;
173 struct fuse_conn *fc = get_fuse_conn(inode);
174
175 if (ff->open_flags & FOPEN_DIRECT_IO)
176 file->f_op = &fuse_direct_io_file_operations;
177 if (!(ff->open_flags & FOPEN_KEEP_CACHE))
178 invalidate_inode_pages2(inode->i_mapping);
179 if (ff->open_flags & FOPEN_NONSEEKABLE)
180 nonseekable_open(inode, file);
181 if (fc->atomic_o_trunc && (file->f_flags & O_TRUNC)) {
182 struct fuse_inode *fi = get_fuse_inode(inode);
183
184 spin_lock(&fc->lock);
185 fi->attr_version = ++fc->attr_version;
186 i_size_write(inode, 0);
187 spin_unlock(&fc->lock);
188 fuse_invalidate_attr(inode);
189 }
190 }
191
192 int fuse_open_common(struct inode *inode, struct file *file, bool isdir)
193 {
194 struct fuse_conn *fc = get_fuse_conn(inode);
195 int err;
196
197 err = generic_file_open(inode, file);
198 if (err)
199 return err;
200
201 err = fuse_do_open(fc, get_node_id(inode), file, isdir);
202 if (err)
203 return err;
204
205 fuse_finish_open(inode, file);
206
207 return 0;
208 }
209
210 static void fuse_prepare_release(struct fuse_file *ff, int flags, int opcode)
211 {
212 struct fuse_conn *fc = ff->fc;
213 struct fuse_req *req = ff->reserved_req;
214 struct fuse_release_in *inarg = &req->misc.release.in;
215
216 spin_lock(&fc->lock);
217 list_del(&ff->write_entry);
218 if (!RB_EMPTY_NODE(&ff->polled_node))
219 rb_erase(&ff->polled_node, &fc->polled_files);
220 spin_unlock(&fc->lock);
221
222 wake_up_interruptible_all(&ff->poll_wait);
223
224 inarg->fh = ff->fh;
225 inarg->flags = flags;
226 req->in.h.opcode = opcode;
227 req->in.h.nodeid = ff->nodeid;
228 req->in.numargs = 1;
229 req->in.args[0].size = sizeof(struct fuse_release_in);
230 req->in.args[0].value = inarg;
231 }
232
233 void fuse_release_common(struct file *file, int opcode)
234 {
235 struct fuse_file *ff;
236 struct fuse_req *req;
237
238 ff = file->private_data;
239 if (unlikely(!ff))
240 return;
241
242 req = ff->reserved_req;
243 fuse_prepare_release(ff, file->f_flags, opcode);
244
245 if (ff->flock) {
246 struct fuse_release_in *inarg = &req->misc.release.in;
247 inarg->release_flags |= FUSE_RELEASE_FLOCK_UNLOCK;
248 inarg->lock_owner = fuse_lock_owner_id(ff->fc,
249 (fl_owner_t) file);
250 }
251 /* Hold vfsmount and dentry until release is finished */
252 path_get(&file->f_path);
253 req->misc.release.path = file->f_path;
254
255 /*
256 * Normally this will send the RELEASE request, however if
257 * some asynchronous READ or WRITE requests are outstanding,
258 * the sending will be delayed.
259 *
260 * Make the release synchronous if this is a fuseblk mount,
261 * synchronous RELEASE is allowed (and desirable) in this case
262 * because the server can be trusted not to screw up.
263 */
264 fuse_file_put(ff, ff->fc->destroy_req != NULL);
265 }
266
267 static int fuse_open(struct inode *inode, struct file *file)
268 {
269 return fuse_open_common(inode, file, false);
270 }
271
272 static int fuse_release(struct inode *inode, struct file *file)
273 {
274 fuse_release_common(file, FUSE_RELEASE);
275
276 /* return value is ignored by VFS */
277 return 0;
278 }
279
280 void fuse_sync_release(struct fuse_file *ff, int flags)
281 {
282 WARN_ON(atomic_read(&ff->count) > 1);
283 fuse_prepare_release(ff, flags, FUSE_RELEASE);
284 ff->reserved_req->force = 1;
285 fuse_request_send(ff->fc, ff->reserved_req);
286 fuse_put_request(ff->fc, ff->reserved_req);
287 kfree(ff);
288 }
289 EXPORT_SYMBOL_GPL(fuse_sync_release);
290
291 /*
292 * Scramble the ID space with XTEA, so that the value of the files_struct
293 * pointer is not exposed to userspace.
294 */
295 u64 fuse_lock_owner_id(struct fuse_conn *fc, fl_owner_t id)
296 {
297 u32 *k = fc->scramble_key;
298 u64 v = (unsigned long) id;
299 u32 v0 = v;
300 u32 v1 = v >> 32;
301 u32 sum = 0;
302 int i;
303
304 for (i = 0; i < 32; i++) {
305 v0 += ((v1 << 4 ^ v1 >> 5) + v1) ^ (sum + k[sum & 3]);
306 sum += 0x9E3779B9;
307 v1 += ((v0 << 4 ^ v0 >> 5) + v0) ^ (sum + k[sum>>11 & 3]);
308 }
309
310 return (u64) v0 + ((u64) v1 << 32);
311 }
312
313 /*
314 * Check if page is under writeback
315 *
316 * This is currently done by walking the list of writepage requests
317 * for the inode, which can be pretty inefficient.
318 */
319 static bool fuse_page_is_writeback(struct inode *inode, pgoff_t index)
320 {
321 struct fuse_conn *fc = get_fuse_conn(inode);
322 struct fuse_inode *fi = get_fuse_inode(inode);
323 struct fuse_req *req;
324 bool found = false;
325
326 spin_lock(&fc->lock);
327 list_for_each_entry(req, &fi->writepages, writepages_entry) {
328 pgoff_t curr_index;
329
330 BUG_ON(req->inode != inode);
331 curr_index = req->misc.write.in.offset >> PAGE_CACHE_SHIFT;
332 if (curr_index == index) {
333 found = true;
334 break;
335 }
336 }
337 spin_unlock(&fc->lock);
338
339 return found;
340 }
341
342 /*
343 * Wait for page writeback to be completed.
344 *
345 * Since fuse doesn't rely on the VM writeback tracking, this has to
346 * use some other means.
347 */
348 static int fuse_wait_on_page_writeback(struct inode *inode, pgoff_t index)
349 {
350 struct fuse_inode *fi = get_fuse_inode(inode);
351
352 wait_event(fi->page_waitq, !fuse_page_is_writeback(inode, index));
353 return 0;
354 }
355
356 static int fuse_flush(struct file *file, fl_owner_t id)
357 {
358 struct inode *inode = file_inode(file);
359 struct fuse_conn *fc = get_fuse_conn(inode);
360 struct fuse_file *ff = file->private_data;
361 struct fuse_req *req;
362 struct fuse_flush_in inarg;
363 int err;
364
365 if (is_bad_inode(inode))
366 return -EIO;
367
368 if (fc->no_flush)
369 return 0;
370
371 req = fuse_get_req_nofail_nopages(fc, file);
372 memset(&inarg, 0, sizeof(inarg));
373 inarg.fh = ff->fh;
374 inarg.lock_owner = fuse_lock_owner_id(fc, id);
375 req->in.h.opcode = FUSE_FLUSH;
376 req->in.h.nodeid = get_node_id(inode);
377 req->in.numargs = 1;
378 req->in.args[0].size = sizeof(inarg);
379 req->in.args[0].value = &inarg;
380 req->force = 1;
381 fuse_request_send(fc, req);
382 err = req->out.h.error;
383 fuse_put_request(fc, req);
384 if (err == -ENOSYS) {
385 fc->no_flush = 1;
386 err = 0;
387 }
388 return err;
389 }
390
391 /*
392 * Wait for all pending writepages on the inode to finish.
393 *
394 * This is currently done by blocking further writes with FUSE_NOWRITE
395 * and waiting for all sent writes to complete.
396 *
397 * This must be called under i_mutex, otherwise the FUSE_NOWRITE usage
398 * could conflict with truncation.
399 */
400 static void fuse_sync_writes(struct inode *inode)
401 {
402 fuse_set_nowrite(inode);
403 fuse_release_nowrite(inode);
404 }
405
406 int fuse_fsync_common(struct file *file, loff_t start, loff_t end,
407 int datasync, int isdir)
408 {
409 struct inode *inode = file->f_mapping->host;
410 struct fuse_conn *fc = get_fuse_conn(inode);
411 struct fuse_file *ff = file->private_data;
412 struct fuse_req *req;
413 struct fuse_fsync_in inarg;
414 int err;
415
416 if (is_bad_inode(inode))
417 return -EIO;
418
419 err = filemap_write_and_wait_range(inode->i_mapping, start, end);
420 if (err)
421 return err;
422
423 if ((!isdir && fc->no_fsync) || (isdir && fc->no_fsyncdir))
424 return 0;
425
426 mutex_lock(&inode->i_mutex);
427
428 /*
429 * Start writeback against all dirty pages of the inode, then
430 * wait for all outstanding writes, before sending the FSYNC
431 * request.
432 */
433 err = write_inode_now(inode, 0);
434 if (err)
435 goto out;
436
437 fuse_sync_writes(inode);
438
439 req = fuse_get_req_nopages(fc);
440 if (IS_ERR(req)) {
441 err = PTR_ERR(req);
442 goto out;
443 }
444
445 memset(&inarg, 0, sizeof(inarg));
446 inarg.fh = ff->fh;
447 inarg.fsync_flags = datasync ? 1 : 0;
448 req->in.h.opcode = isdir ? FUSE_FSYNCDIR : FUSE_FSYNC;
449 req->in.h.nodeid = get_node_id(inode);
450 req->in.numargs = 1;
451 req->in.args[0].size = sizeof(inarg);
452 req->in.args[0].value = &inarg;
453 fuse_request_send(fc, req);
454 err = req->out.h.error;
455 fuse_put_request(fc, req);
456 if (err == -ENOSYS) {
457 if (isdir)
458 fc->no_fsyncdir = 1;
459 else
460 fc->no_fsync = 1;
461 err = 0;
462 }
463 out:
464 mutex_unlock(&inode->i_mutex);
465 return err;
466 }
467
468 static int fuse_fsync(struct file *file, loff_t start, loff_t end,
469 int datasync)
470 {
471 return fuse_fsync_common(file, start, end, datasync, 0);
472 }
473
474 void fuse_read_fill(struct fuse_req *req, struct file *file, loff_t pos,
475 size_t count, int opcode)
476 {
477 struct fuse_read_in *inarg = &req->misc.read.in;
478 struct fuse_file *ff = file->private_data;
479
480 inarg->fh = ff->fh;
481 inarg->offset = pos;
482 inarg->size = count;
483 inarg->flags = file->f_flags;
484 req->in.h.opcode = opcode;
485 req->in.h.nodeid = ff->nodeid;
486 req->in.numargs = 1;
487 req->in.args[0].size = sizeof(struct fuse_read_in);
488 req->in.args[0].value = inarg;
489 req->out.argvar = 1;
490 req->out.numargs = 1;
491 req->out.args[0].size = count;
492 }
493
494 static size_t fuse_send_read(struct fuse_req *req, struct file *file,
495 loff_t pos, size_t count, fl_owner_t owner)
496 {
497 struct fuse_file *ff = file->private_data;
498 struct fuse_conn *fc = ff->fc;
499
500 fuse_read_fill(req, file, pos, count, FUSE_READ);
501 if (owner != NULL) {
502 struct fuse_read_in *inarg = &req->misc.read.in;
503
504 inarg->read_flags |= FUSE_READ_LOCKOWNER;
505 inarg->lock_owner = fuse_lock_owner_id(fc, owner);
506 }
507 fuse_request_send(fc, req);
508 return req->out.args[0].size;
509 }
510
511 static void fuse_read_update_size(struct inode *inode, loff_t size,
512 u64 attr_ver)
513 {
514 struct fuse_conn *fc = get_fuse_conn(inode);
515 struct fuse_inode *fi = get_fuse_inode(inode);
516
517 spin_lock(&fc->lock);
518 if (attr_ver == fi->attr_version && size < inode->i_size) {
519 fi->attr_version = ++fc->attr_version;
520 i_size_write(inode, size);
521 }
522 spin_unlock(&fc->lock);
523 }
524
525 static int fuse_readpage(struct file *file, struct page *page)
526 {
527 struct inode *inode = page->mapping->host;
528 struct fuse_conn *fc = get_fuse_conn(inode);
529 struct fuse_req *req;
530 size_t num_read;
531 loff_t pos = page_offset(page);
532 size_t count = PAGE_CACHE_SIZE;
533 u64 attr_ver;
534 int err;
535
536 err = -EIO;
537 if (is_bad_inode(inode))
538 goto out;
539
540 /*
541 * Page writeback can extend beyond the lifetime of the
542 * page-cache page, so make sure we read a properly synced
543 * page.
544 */
545 fuse_wait_on_page_writeback(inode, page->index);
546
547 req = fuse_get_req(fc, 1);
548 err = PTR_ERR(req);
549 if (IS_ERR(req))
550 goto out;
551
552 attr_ver = fuse_get_attr_version(fc);
553
554 req->out.page_zeroing = 1;
555 req->out.argpages = 1;
556 req->num_pages = 1;
557 req->pages[0] = page;
558 req->page_descs[0].length = count;
559 num_read = fuse_send_read(req, file, pos, count, NULL);
560 err = req->out.h.error;
561 fuse_put_request(fc, req);
562
563 if (!err) {
564 /*
565 * Short read means EOF. If file size is larger, truncate it
566 */
567 if (num_read < count)
568 fuse_read_update_size(inode, pos + num_read, attr_ver);
569
570 SetPageUptodate(page);
571 }
572
573 fuse_invalidate_attr(inode); /* atime changed */
574 out:
575 unlock_page(page);
576 return err;
577 }
578
579 static void fuse_readpages_end(struct fuse_conn *fc, struct fuse_req *req)
580 {
581 int i;
582 size_t count = req->misc.read.in.size;
583 size_t num_read = req->out.args[0].size;
584 struct address_space *mapping = NULL;
585
586 for (i = 0; mapping == NULL && i < req->num_pages; i++)
587 mapping = req->pages[i]->mapping;
588
589 if (mapping) {
590 struct inode *inode = mapping->host;
591
592 /*
593 * Short read means EOF. If file size is larger, truncate it
594 */
595 if (!req->out.h.error && num_read < count) {
596 loff_t pos;
597
598 pos = page_offset(req->pages[0]) + num_read;
599 fuse_read_update_size(inode, pos,
600 req->misc.read.attr_ver);
601 }
602 fuse_invalidate_attr(inode); /* atime changed */
603 }
604
605 for (i = 0; i < req->num_pages; i++) {
606 struct page *page = req->pages[i];
607 if (!req->out.h.error)
608 SetPageUptodate(page);
609 else
610 SetPageError(page);
611 unlock_page(page);
612 page_cache_release(page);
613 }
614 if (req->ff)
615 fuse_file_put(req->ff, false);
616 }
617
618 static void fuse_send_readpages(struct fuse_req *req, struct file *file)
619 {
620 struct fuse_file *ff = file->private_data;
621 struct fuse_conn *fc = ff->fc;
622 loff_t pos = page_offset(req->pages[0]);
623 size_t count = req->num_pages << PAGE_CACHE_SHIFT;
624
625 req->out.argpages = 1;
626 req->out.page_zeroing = 1;
627 req->out.page_replace = 1;
628 fuse_read_fill(req, file, pos, count, FUSE_READ);
629 req->misc.read.attr_ver = fuse_get_attr_version(fc);
630 if (fc->async_read) {
631 req->ff = fuse_file_get(ff);
632 req->end = fuse_readpages_end;
633 fuse_request_send_background(fc, req);
634 } else {
635 fuse_request_send(fc, req);
636 fuse_readpages_end(fc, req);
637 fuse_put_request(fc, req);
638 }
639 }
640
641 struct fuse_fill_data {
642 struct fuse_req *req;
643 struct file *file;
644 struct inode *inode;
645 unsigned nr_pages;
646 };
647
648 static int fuse_readpages_fill(void *_data, struct page *page)
649 {
650 struct fuse_fill_data *data = _data;
651 struct fuse_req *req = data->req;
652 struct inode *inode = data->inode;
653 struct fuse_conn *fc = get_fuse_conn(inode);
654
655 fuse_wait_on_page_writeback(inode, page->index);
656
657 if (req->num_pages &&
658 (req->num_pages == FUSE_MAX_PAGES_PER_REQ ||
659 (req->num_pages + 1) * PAGE_CACHE_SIZE > fc->max_read ||
660 req->pages[req->num_pages - 1]->index + 1 != page->index)) {
661 int nr_alloc = min_t(unsigned, data->nr_pages,
662 FUSE_MAX_PAGES_PER_REQ);
663 fuse_send_readpages(req, data->file);
664 data->req = req = fuse_get_req(fc, nr_alloc);
665 if (IS_ERR(req)) {
666 unlock_page(page);
667 return PTR_ERR(req);
668 }
669 }
670
671 if (WARN_ON(req->num_pages >= req->max_pages)) {
672 fuse_put_request(fc, req);
673 return -EIO;
674 }
675
676 page_cache_get(page);
677 req->pages[req->num_pages] = page;
678 req->page_descs[req->num_pages].length = PAGE_SIZE;
679 req->num_pages++;
680 data->nr_pages--;
681 return 0;
682 }
683
684 static int fuse_readpages(struct file *file, struct address_space *mapping,
685 struct list_head *pages, unsigned nr_pages)
686 {
687 struct inode *inode = mapping->host;
688 struct fuse_conn *fc = get_fuse_conn(inode);
689 struct fuse_fill_data data;
690 int err;
691 int nr_alloc = min_t(unsigned, nr_pages, FUSE_MAX_PAGES_PER_REQ);
692
693 err = -EIO;
694 if (is_bad_inode(inode))
695 goto out;
696
697 data.file = file;
698 data.inode = inode;
699 data.req = fuse_get_req(fc, nr_alloc);
700 data.nr_pages = nr_pages;
701 err = PTR_ERR(data.req);
702 if (IS_ERR(data.req))
703 goto out;
704
705 err = read_cache_pages(mapping, pages, fuse_readpages_fill, &data);
706 if (!err) {
707 if (data.req->num_pages)
708 fuse_send_readpages(data.req, file);
709 else
710 fuse_put_request(fc, data.req);
711 }
712 out:
713 return err;
714 }
715
716 static ssize_t fuse_file_aio_read(struct kiocb *iocb, const struct iovec *iov,
717 unsigned long nr_segs, loff_t pos)
718 {
719 struct inode *inode = iocb->ki_filp->f_mapping->host;
720 struct fuse_conn *fc = get_fuse_conn(inode);
721
722 /*
723 * In auto invalidate mode, always update attributes on read.
724 * Otherwise, only update if we attempt to read past EOF (to ensure
725 * i_size is up to date).
726 */
727 if (fc->auto_inval_data ||
728 (pos + iov_length(iov, nr_segs) > i_size_read(inode))) {
729 int err;
730 err = fuse_update_attributes(inode, NULL, iocb->ki_filp, NULL);
731 if (err)
732 return err;
733 }
734
735 return generic_file_aio_read(iocb, iov, nr_segs, pos);
736 }
737
738 static void fuse_write_fill(struct fuse_req *req, struct fuse_file *ff,
739 loff_t pos, size_t count)
740 {
741 struct fuse_write_in *inarg = &req->misc.write.in;
742 struct fuse_write_out *outarg = &req->misc.write.out;
743
744 inarg->fh = ff->fh;
745 inarg->offset = pos;
746 inarg->size = count;
747 req->in.h.opcode = FUSE_WRITE;
748 req->in.h.nodeid = ff->nodeid;
749 req->in.numargs = 2;
750 if (ff->fc->minor < 9)
751 req->in.args[0].size = FUSE_COMPAT_WRITE_IN_SIZE;
752 else
753 req->in.args[0].size = sizeof(struct fuse_write_in);
754 req->in.args[0].value = inarg;
755 req->in.args[1].size = count;
756 req->out.numargs = 1;
757 req->out.args[0].size = sizeof(struct fuse_write_out);
758 req->out.args[0].value = outarg;
759 }
760
761 static size_t fuse_send_write(struct fuse_req *req, struct file *file,
762 loff_t pos, size_t count, fl_owner_t owner)
763 {
764 struct fuse_file *ff = file->private_data;
765 struct fuse_conn *fc = ff->fc;
766 struct fuse_write_in *inarg = &req->misc.write.in;
767
768 fuse_write_fill(req, ff, pos, count);
769 inarg->flags = file->f_flags;
770 if (owner != NULL) {
771 inarg->write_flags |= FUSE_WRITE_LOCKOWNER;
772 inarg->lock_owner = fuse_lock_owner_id(fc, owner);
773 }
774 fuse_request_send(fc, req);
775 return req->misc.write.out.size;
776 }
777
778 void fuse_write_update_size(struct inode *inode, loff_t pos)
779 {
780 struct fuse_conn *fc = get_fuse_conn(inode);
781 struct fuse_inode *fi = get_fuse_inode(inode);
782
783 spin_lock(&fc->lock);
784 fi->attr_version = ++fc->attr_version;
785 if (pos > inode->i_size)
786 i_size_write(inode, pos);
787 spin_unlock(&fc->lock);
788 }
789
790 static size_t fuse_send_write_pages(struct fuse_req *req, struct file *file,
791 struct inode *inode, loff_t pos,
792 size_t count)
793 {
794 size_t res;
795 unsigned offset;
796 unsigned i;
797
798 for (i = 0; i < req->num_pages; i++)
799 fuse_wait_on_page_writeback(inode, req->pages[i]->index);
800
801 res = fuse_send_write(req, file, pos, count, NULL);
802
803 offset = req->page_descs[0].offset;
804 count = res;
805 for (i = 0; i < req->num_pages; i++) {
806 struct page *page = req->pages[i];
807
808 if (!req->out.h.error && !offset && count >= PAGE_CACHE_SIZE)
809 SetPageUptodate(page);
810
811 if (count > PAGE_CACHE_SIZE - offset)
812 count -= PAGE_CACHE_SIZE - offset;
813 else
814 count = 0;
815 offset = 0;
816
817 unlock_page(page);
818 page_cache_release(page);
819 }
820
821 return res;
822 }
823
824 static ssize_t fuse_fill_write_pages(struct fuse_req *req,
825 struct address_space *mapping,
826 struct iov_iter *ii, loff_t pos)
827 {
828 struct fuse_conn *fc = get_fuse_conn(mapping->host);
829 unsigned offset = pos & (PAGE_CACHE_SIZE - 1);
830 size_t count = 0;
831 int err;
832
833 req->in.argpages = 1;
834 req->page_descs[0].offset = offset;
835
836 do {
837 size_t tmp;
838 struct page *page;
839 pgoff_t index = pos >> PAGE_CACHE_SHIFT;
840 size_t bytes = min_t(size_t, PAGE_CACHE_SIZE - offset,
841 iov_iter_count(ii));
842
843 bytes = min_t(size_t, bytes, fc->max_write - count);
844
845 again:
846 err = -EFAULT;
847 if (iov_iter_fault_in_readable(ii, bytes))
848 break;
849
850 err = -ENOMEM;
851 page = grab_cache_page_write_begin(mapping, index, 0);
852 if (!page)
853 break;
854
855 if (mapping_writably_mapped(mapping))
856 flush_dcache_page(page);
857
858 pagefault_disable();
859 tmp = iov_iter_copy_from_user_atomic(page, ii, offset, bytes);
860 pagefault_enable();
861 flush_dcache_page(page);
862
863 mark_page_accessed(page);
864
865 if (!tmp) {
866 unlock_page(page);
867 page_cache_release(page);
868 bytes = min(bytes, iov_iter_single_seg_count(ii));
869 goto again;
870 }
871
872 err = 0;
873 req->pages[req->num_pages] = page;
874 req->page_descs[req->num_pages].length = tmp;
875 req->num_pages++;
876
877 iov_iter_advance(ii, tmp);
878 count += tmp;
879 pos += tmp;
880 offset += tmp;
881 if (offset == PAGE_CACHE_SIZE)
882 offset = 0;
883
884 if (!fc->big_writes)
885 break;
886 } while (iov_iter_count(ii) && count < fc->max_write &&
887 req->num_pages < req->max_pages && offset == 0);
888
889 return count > 0 ? count : err;
890 }
891
892 static inline unsigned fuse_wr_pages(loff_t pos, size_t len)
893 {
894 return min_t(unsigned,
895 ((pos + len - 1) >> PAGE_CACHE_SHIFT) -
896 (pos >> PAGE_CACHE_SHIFT) + 1,
897 FUSE_MAX_PAGES_PER_REQ);
898 }
899
900 static ssize_t fuse_perform_write(struct file *file,
901 struct address_space *mapping,
902 struct iov_iter *ii, loff_t pos)
903 {
904 struct inode *inode = mapping->host;
905 struct fuse_conn *fc = get_fuse_conn(inode);
906 int err = 0;
907 ssize_t res = 0;
908
909 if (is_bad_inode(inode))
910 return -EIO;
911
912 do {
913 struct fuse_req *req;
914 ssize_t count;
915 unsigned nr_pages = fuse_wr_pages(pos, iov_iter_count(ii));
916
917 req = fuse_get_req(fc, nr_pages);
918 if (IS_ERR(req)) {
919 err = PTR_ERR(req);
920 break;
921 }
922
923 count = fuse_fill_write_pages(req, mapping, ii, pos);
924 if (count <= 0) {
925 err = count;
926 } else {
927 size_t num_written;
928
929 num_written = fuse_send_write_pages(req, file, inode,
930 pos, count);
931 err = req->out.h.error;
932 if (!err) {
933 res += num_written;
934 pos += num_written;
935
936 /* break out of the loop on short write */
937 if (num_written != count)
938 err = -EIO;
939 }
940 }
941 fuse_put_request(fc, req);
942 } while (!err && iov_iter_count(ii));
943
944 if (res > 0)
945 fuse_write_update_size(inode, pos);
946
947 fuse_invalidate_attr(inode);
948
949 return res > 0 ? res : err;
950 }
951
952 static ssize_t fuse_file_aio_write(struct kiocb *iocb, const struct iovec *iov,
953 unsigned long nr_segs, loff_t pos)
954 {
955 struct file *file = iocb->ki_filp;
956 struct address_space *mapping = file->f_mapping;
957 size_t count = 0;
958 size_t ocount = 0;
959 ssize_t written = 0;
960 ssize_t written_buffered = 0;
961 struct inode *inode = mapping->host;
962 ssize_t err;
963 struct iov_iter i;
964 loff_t endbyte = 0;
965
966 WARN_ON(iocb->ki_pos != pos);
967
968 ocount = 0;
969 err = generic_segment_checks(iov, &nr_segs, &ocount, VERIFY_READ);
970 if (err)
971 return err;
972
973 count = ocount;
974 mutex_lock(&inode->i_mutex);
975
976 /* We can write back this queue in page reclaim */
977 current->backing_dev_info = mapping->backing_dev_info;
978
979 err = generic_write_checks(file, &pos, &count, S_ISBLK(inode->i_mode));
980 if (err)
981 goto out;
982
983 if (count == 0)
984 goto out;
985
986 err = file_remove_suid(file);
987 if (err)
988 goto out;
989
990 err = file_update_time(file);
991 if (err)
992 goto out;
993
994 if (file->f_flags & O_DIRECT) {
995 written = generic_file_direct_write(iocb, iov, &nr_segs,
996 pos, &iocb->ki_pos,
997 count, ocount);
998 if (written < 0 || written == count)
999 goto out;
1000
1001 pos += written;
1002 count -= written;
1003
1004 iov_iter_init(&i, iov, nr_segs, count, written);
1005 written_buffered = fuse_perform_write(file, mapping, &i, pos);
1006 if (written_buffered < 0) {
1007 err = written_buffered;
1008 goto out;
1009 }
1010 endbyte = pos + written_buffered - 1;
1011
1012 err = filemap_write_and_wait_range(file->f_mapping, pos,
1013 endbyte);
1014 if (err)
1015 goto out;
1016
1017 invalidate_mapping_pages(file->f_mapping,
1018 pos >> PAGE_CACHE_SHIFT,
1019 endbyte >> PAGE_CACHE_SHIFT);
1020
1021 written += written_buffered;
1022 iocb->ki_pos = pos + written_buffered;
1023 } else {
1024 iov_iter_init(&i, iov, nr_segs, count, 0);
1025 written = fuse_perform_write(file, mapping, &i, pos);
1026 if (written >= 0)
1027 iocb->ki_pos = pos + written;
1028 }
1029 out:
1030 current->backing_dev_info = NULL;
1031 mutex_unlock(&inode->i_mutex);
1032
1033 return written ? written : err;
1034 }
1035
1036 static void fuse_release_user_pages(struct fuse_req *req, int write)
1037 {
1038 unsigned i;
1039
1040 for (i = 0; i < req->num_pages; i++) {
1041 struct page *page = req->pages[i];
1042 if (write)
1043 set_page_dirty_lock(page);
1044 put_page(page);
1045 }
1046 }
1047
1048 static inline void fuse_page_descs_length_init(struct fuse_req *req,
1049 unsigned index, unsigned nr_pages)
1050 {
1051 int i;
1052
1053 for (i = index; i < index + nr_pages; i++)
1054 req->page_descs[i].length = PAGE_SIZE -
1055 req->page_descs[i].offset;
1056 }
1057
1058 static inline unsigned long fuse_get_user_addr(const struct iov_iter *ii)
1059 {
1060 return (unsigned long)ii->iov->iov_base + ii->iov_offset;
1061 }
1062
1063 static inline size_t fuse_get_frag_size(const struct iov_iter *ii,
1064 size_t max_size)
1065 {
1066 return min(iov_iter_single_seg_count(ii), max_size);
1067 }
1068
1069 static int fuse_get_user_pages(struct fuse_req *req, struct iov_iter *ii,
1070 size_t *nbytesp, int write)
1071 {
1072 size_t nbytes = 0; /* # bytes already packed in req */
1073
1074 /* Special case for kernel I/O: can copy directly into the buffer */
1075 if (segment_eq(get_fs(), KERNEL_DS)) {
1076 unsigned long user_addr = fuse_get_user_addr(ii);
1077 size_t frag_size = fuse_get_frag_size(ii, *nbytesp);
1078
1079 if (write)
1080 req->in.args[1].value = (void *) user_addr;
1081 else
1082 req->out.args[0].value = (void *) user_addr;
1083
1084 iov_iter_advance(ii, frag_size);
1085 *nbytesp = frag_size;
1086 return 0;
1087 }
1088
1089 while (nbytes < *nbytesp && req->num_pages < req->max_pages) {
1090 unsigned npages;
1091 unsigned long user_addr = fuse_get_user_addr(ii);
1092 unsigned offset = user_addr & ~PAGE_MASK;
1093 size_t frag_size = fuse_get_frag_size(ii, *nbytesp - nbytes);
1094 int ret;
1095
1096 unsigned n = req->max_pages - req->num_pages;
1097 frag_size = min_t(size_t, frag_size, n << PAGE_SHIFT);
1098
1099 npages = (frag_size + offset + PAGE_SIZE - 1) >> PAGE_SHIFT;
1100 npages = clamp(npages, 1U, n);
1101
1102 ret = get_user_pages_fast(user_addr, npages, !write,
1103 &req->pages[req->num_pages]);
1104 if (ret < 0)
1105 return ret;
1106
1107 npages = ret;
1108 frag_size = min_t(size_t, frag_size,
1109 (npages << PAGE_SHIFT) - offset);
1110 iov_iter_advance(ii, frag_size);
1111
1112 req->page_descs[req->num_pages].offset = offset;
1113 fuse_page_descs_length_init(req, req->num_pages, npages);
1114
1115 req->num_pages += npages;
1116 req->page_descs[req->num_pages - 1].length -=
1117 (npages << PAGE_SHIFT) - offset - frag_size;
1118
1119 nbytes += frag_size;
1120 }
1121
1122 if (write)
1123 req->in.argpages = 1;
1124 else
1125 req->out.argpages = 1;
1126
1127 *nbytesp = nbytes;
1128
1129 return 0;
1130 }
1131
1132 static inline int fuse_iter_npages(const struct iov_iter *ii_p)
1133 {
1134 struct iov_iter ii = *ii_p;
1135 int npages = 0;
1136
1137 while (iov_iter_count(&ii) && npages < FUSE_MAX_PAGES_PER_REQ) {
1138 unsigned long user_addr = fuse_get_user_addr(&ii);
1139 unsigned offset = user_addr & ~PAGE_MASK;
1140 size_t frag_size = iov_iter_single_seg_count(&ii);
1141
1142 npages += (frag_size + offset + PAGE_SIZE - 1) >> PAGE_SHIFT;
1143 iov_iter_advance(&ii, frag_size);
1144 }
1145
1146 return min(npages, FUSE_MAX_PAGES_PER_REQ);
1147 }
1148
1149 ssize_t fuse_direct_io(struct file *file, const struct iovec *iov,
1150 unsigned long nr_segs, size_t count, loff_t *ppos,
1151 int write)
1152 {
1153 struct fuse_file *ff = file->private_data;
1154 struct fuse_conn *fc = ff->fc;
1155 size_t nmax = write ? fc->max_write : fc->max_read;
1156 loff_t pos = *ppos;
1157 ssize_t res = 0;
1158 struct fuse_req *req;
1159 struct iov_iter ii;
1160
1161 iov_iter_init(&ii, iov, nr_segs, count, 0);
1162
1163 req = fuse_get_req(fc, fuse_iter_npages(&ii));
1164 if (IS_ERR(req))
1165 return PTR_ERR(req);
1166
1167 while (count) {
1168 size_t nres;
1169 fl_owner_t owner = current->files;
1170 size_t nbytes = min(count, nmax);
1171 int err = fuse_get_user_pages(req, &ii, &nbytes, write);
1172 if (err) {
1173 res = err;
1174 break;
1175 }
1176
1177 if (write)
1178 nres = fuse_send_write(req, file, pos, nbytes, owner);
1179 else
1180 nres = fuse_send_read(req, file, pos, nbytes, owner);
1181
1182 fuse_release_user_pages(req, !write);
1183 if (req->out.h.error) {
1184 if (!res)
1185 res = req->out.h.error;
1186 break;
1187 } else if (nres > nbytes) {
1188 res = -EIO;
1189 break;
1190 }
1191 count -= nres;
1192 res += nres;
1193 pos += nres;
1194 if (nres != nbytes)
1195 break;
1196 if (count) {
1197 fuse_put_request(fc, req);
1198 req = fuse_get_req(fc, fuse_iter_npages(&ii));
1199 if (IS_ERR(req))
1200 break;
1201 }
1202 }
1203 if (!IS_ERR(req))
1204 fuse_put_request(fc, req);
1205 if (res > 0)
1206 *ppos = pos;
1207
1208 return res;
1209 }
1210 EXPORT_SYMBOL_GPL(fuse_direct_io);
1211
1212 static ssize_t __fuse_direct_read(struct file *file, const struct iovec *iov,
1213 unsigned long nr_segs, loff_t *ppos)
1214 {
1215 ssize_t res;
1216 struct inode *inode = file_inode(file);
1217
1218 if (is_bad_inode(inode))
1219 return -EIO;
1220
1221 res = fuse_direct_io(file, iov, nr_segs, iov_length(iov, nr_segs),
1222 ppos, 0);
1223
1224 fuse_invalidate_attr(inode);
1225
1226 return res;
1227 }
1228
1229 static ssize_t fuse_direct_read(struct file *file, char __user *buf,
1230 size_t count, loff_t *ppos)
1231 {
1232 struct iovec iov = { .iov_base = buf, .iov_len = count };
1233 return __fuse_direct_read(file, &iov, 1, ppos);
1234 }
1235
1236 static ssize_t __fuse_direct_write(struct file *file, const struct iovec *iov,
1237 unsigned long nr_segs, loff_t *ppos)
1238 {
1239 struct inode *inode = file_inode(file);
1240 size_t count = iov_length(iov, nr_segs);
1241 ssize_t res;
1242
1243 res = generic_write_checks(file, ppos, &count, 0);
1244 if (!res) {
1245 res = fuse_direct_io(file, iov, nr_segs, count, ppos, 1);
1246 if (res > 0)
1247 fuse_write_update_size(inode, *ppos);
1248 }
1249
1250 fuse_invalidate_attr(inode);
1251
1252 return res;
1253 }
1254
1255 static ssize_t fuse_direct_write(struct file *file, const char __user *buf,
1256 size_t count, loff_t *ppos)
1257 {
1258 struct iovec iov = { .iov_base = (void __user *)buf, .iov_len = count };
1259 struct inode *inode = file_inode(file);
1260 ssize_t res;
1261
1262 if (is_bad_inode(inode))
1263 return -EIO;
1264
1265 /* Don't allow parallel writes to the same file */
1266 mutex_lock(&inode->i_mutex);
1267 res = __fuse_direct_write(file, &iov, 1, ppos);
1268 mutex_unlock(&inode->i_mutex);
1269
1270 return res;
1271 }
1272
1273 static void fuse_writepage_free(struct fuse_conn *fc, struct fuse_req *req)
1274 {
1275 __free_page(req->pages[0]);
1276 fuse_file_put(req->ff, false);
1277 }
1278
1279 static void fuse_writepage_finish(struct fuse_conn *fc, struct fuse_req *req)
1280 {
1281 struct inode *inode = req->inode;
1282 struct fuse_inode *fi = get_fuse_inode(inode);
1283 struct backing_dev_info *bdi = inode->i_mapping->backing_dev_info;
1284
1285 list_del(&req->writepages_entry);
1286 dec_bdi_stat(bdi, BDI_WRITEBACK);
1287 dec_zone_page_state(req->pages[0], NR_WRITEBACK_TEMP);
1288 bdi_writeout_inc(bdi);
1289 wake_up(&fi->page_waitq);
1290 }
1291
1292 /* Called under fc->lock, may release and reacquire it */
1293 static void fuse_send_writepage(struct fuse_conn *fc, struct fuse_req *req)
1294 __releases(fc->lock)
1295 __acquires(fc->lock)
1296 {
1297 struct fuse_inode *fi = get_fuse_inode(req->inode);
1298 loff_t size = i_size_read(req->inode);
1299 struct fuse_write_in *inarg = &req->misc.write.in;
1300
1301 if (!fc->connected)
1302 goto out_free;
1303
1304 if (inarg->offset + PAGE_CACHE_SIZE <= size) {
1305 inarg->size = PAGE_CACHE_SIZE;
1306 } else if (inarg->offset < size) {
1307 inarg->size = size & (PAGE_CACHE_SIZE - 1);
1308 } else {
1309 /* Got truncated off completely */
1310 goto out_free;
1311 }
1312
1313 req->in.args[1].size = inarg->size;
1314 fi->writectr++;
1315 fuse_request_send_background_locked(fc, req);
1316 return;
1317
1318 out_free:
1319 fuse_writepage_finish(fc, req);
1320 spin_unlock(&fc->lock);
1321 fuse_writepage_free(fc, req);
1322 fuse_put_request(fc, req);
1323 spin_lock(&fc->lock);
1324 }
1325
1326 /*
1327 * If fi->writectr is positive (no truncate or fsync going on) send
1328 * all queued writepage requests.
1329 *
1330 * Called with fc->lock
1331 */
1332 void fuse_flush_writepages(struct inode *inode)
1333 __releases(fc->lock)
1334 __acquires(fc->lock)
1335 {
1336 struct fuse_conn *fc = get_fuse_conn(inode);
1337 struct fuse_inode *fi = get_fuse_inode(inode);
1338 struct fuse_req *req;
1339
1340 while (fi->writectr >= 0 && !list_empty(&fi->queued_writes)) {
1341 req = list_entry(fi->queued_writes.next, struct fuse_req, list);
1342 list_del_init(&req->list);
1343 fuse_send_writepage(fc, req);
1344 }
1345 }
1346
1347 static void fuse_writepage_end(struct fuse_conn *fc, struct fuse_req *req)
1348 {
1349 struct inode *inode = req->inode;
1350 struct fuse_inode *fi = get_fuse_inode(inode);
1351
1352 mapping_set_error(inode->i_mapping, req->out.h.error);
1353 spin_lock(&fc->lock);
1354 fi->writectr--;
1355 fuse_writepage_finish(fc, req);
1356 spin_unlock(&fc->lock);
1357 fuse_writepage_free(fc, req);
1358 }
1359
1360 static int fuse_writepage_locked(struct page *page)
1361 {
1362 struct address_space *mapping = page->mapping;
1363 struct inode *inode = mapping->host;
1364 struct fuse_conn *fc = get_fuse_conn(inode);
1365 struct fuse_inode *fi = get_fuse_inode(inode);
1366 struct fuse_req *req;
1367 struct fuse_file *ff;
1368 struct page *tmp_page;
1369
1370 set_page_writeback(page);
1371
1372 req = fuse_request_alloc_nofs(1);
1373 if (!req)
1374 goto err;
1375
1376 tmp_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
1377 if (!tmp_page)
1378 goto err_free;
1379
1380 spin_lock(&fc->lock);
1381 BUG_ON(list_empty(&fi->write_files));
1382 ff = list_entry(fi->write_files.next, struct fuse_file, write_entry);
1383 req->ff = fuse_file_get(ff);
1384 spin_unlock(&fc->lock);
1385
1386 fuse_write_fill(req, ff, page_offset(page), 0);
1387
1388 copy_highpage(tmp_page, page);
1389 req->misc.write.in.write_flags |= FUSE_WRITE_CACHE;
1390 req->in.argpages = 1;
1391 req->num_pages = 1;
1392 req->pages[0] = tmp_page;
1393 req->page_descs[0].offset = 0;
1394 req->page_descs[0].length = PAGE_SIZE;
1395 req->end = fuse_writepage_end;
1396 req->inode = inode;
1397
1398 inc_bdi_stat(mapping->backing_dev_info, BDI_WRITEBACK);
1399 inc_zone_page_state(tmp_page, NR_WRITEBACK_TEMP);
1400 end_page_writeback(page);
1401
1402 spin_lock(&fc->lock);
1403 list_add(&req->writepages_entry, &fi->writepages);
1404 list_add_tail(&req->list, &fi->queued_writes);
1405 fuse_flush_writepages(inode);
1406 spin_unlock(&fc->lock);
1407
1408 return 0;
1409
1410 err_free:
1411 fuse_request_free(req);
1412 err:
1413 end_page_writeback(page);
1414 return -ENOMEM;
1415 }
1416
1417 static int fuse_writepage(struct page *page, struct writeback_control *wbc)
1418 {
1419 int err;
1420
1421 err = fuse_writepage_locked(page);
1422 unlock_page(page);
1423
1424 return err;
1425 }
1426
1427 static int fuse_launder_page(struct page *page)
1428 {
1429 int err = 0;
1430 if (clear_page_dirty_for_io(page)) {
1431 struct inode *inode = page->mapping->host;
1432 err = fuse_writepage_locked(page);
1433 if (!err)
1434 fuse_wait_on_page_writeback(inode, page->index);
1435 }
1436 return err;
1437 }
1438
1439 /*
1440 * Write back dirty pages now, because there may not be any suitable
1441 * open files later
1442 */
1443 static void fuse_vma_close(struct vm_area_struct *vma)
1444 {
1445 filemap_write_and_wait(vma->vm_file->f_mapping);
1446 }
1447
1448 /*
1449 * Wait for writeback against this page to complete before allowing it
1450 * to be marked dirty again, and hence written back again, possibly
1451 * before the previous writepage completed.
1452 *
1453 * Block here, instead of in ->writepage(), so that the userspace fs
1454 * can only block processes actually operating on the filesystem.
1455 *
1456 * Otherwise unprivileged userspace fs would be able to block
1457 * unrelated:
1458 *
1459 * - page migration
1460 * - sync(2)
1461 * - try_to_free_pages() with order > PAGE_ALLOC_COSTLY_ORDER
1462 */
1463 static int fuse_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
1464 {
1465 struct page *page = vmf->page;
1466 /*
1467 * Don't use page->mapping as it may become NULL from a
1468 * concurrent truncate.
1469 */
1470 struct inode *inode = vma->vm_file->f_mapping->host;
1471
1472 fuse_wait_on_page_writeback(inode, page->index);
1473 return 0;
1474 }
1475
1476 static const struct vm_operations_struct fuse_file_vm_ops = {
1477 .close = fuse_vma_close,
1478 .fault = filemap_fault,
1479 .page_mkwrite = fuse_page_mkwrite,
1480 .remap_pages = generic_file_remap_pages,
1481 };
1482
1483 static int fuse_file_mmap(struct file *file, struct vm_area_struct *vma)
1484 {
1485 if ((vma->vm_flags & VM_SHARED) && (vma->vm_flags & VM_MAYWRITE)) {
1486 struct inode *inode = file_inode(file);
1487 struct fuse_conn *fc = get_fuse_conn(inode);
1488 struct fuse_inode *fi = get_fuse_inode(inode);
1489 struct fuse_file *ff = file->private_data;
1490 /*
1491 * file may be written through mmap, so chain it onto the
1492 * inodes's write_file list
1493 */
1494 spin_lock(&fc->lock);
1495 if (list_empty(&ff->write_entry))
1496 list_add(&ff->write_entry, &fi->write_files);
1497 spin_unlock(&fc->lock);
1498 }
1499 file_accessed(file);
1500 vma->vm_ops = &fuse_file_vm_ops;
1501 return 0;
1502 }
1503
1504 static int fuse_direct_mmap(struct file *file, struct vm_area_struct *vma)
1505 {
1506 /* Can't provide the coherency needed for MAP_SHARED */
1507 if (vma->vm_flags & VM_MAYSHARE)
1508 return -ENODEV;
1509
1510 invalidate_inode_pages2(file->f_mapping);
1511
1512 return generic_file_mmap(file, vma);
1513 }
1514
1515 static int convert_fuse_file_lock(const struct fuse_file_lock *ffl,
1516 struct file_lock *fl)
1517 {
1518 switch (ffl->type) {
1519 case F_UNLCK:
1520 break;
1521
1522 case F_RDLCK:
1523 case F_WRLCK:
1524 if (ffl->start > OFFSET_MAX || ffl->end > OFFSET_MAX ||
1525 ffl->end < ffl->start)
1526 return -EIO;
1527
1528 fl->fl_start = ffl->start;
1529 fl->fl_end = ffl->end;
1530 fl->fl_pid = ffl->pid;
1531 break;
1532
1533 default:
1534 return -EIO;
1535 }
1536 fl->fl_type = ffl->type;
1537 return 0;
1538 }
1539
1540 static void fuse_lk_fill(struct fuse_req *req, struct file *file,
1541 const struct file_lock *fl, int opcode, pid_t pid,
1542 int flock)
1543 {
1544 struct inode *inode = file_inode(file);
1545 struct fuse_conn *fc = get_fuse_conn(inode);
1546 struct fuse_file *ff = file->private_data;
1547 struct fuse_lk_in *arg = &req->misc.lk_in;
1548
1549 arg->fh = ff->fh;
1550 arg->owner = fuse_lock_owner_id(fc, fl->fl_owner);
1551 arg->lk.start = fl->fl_start;
1552 arg->lk.end = fl->fl_end;
1553 arg->lk.type = fl->fl_type;
1554 arg->lk.pid = pid;
1555 if (flock)
1556 arg->lk_flags |= FUSE_LK_FLOCK;
1557 req->in.h.opcode = opcode;
1558 req->in.h.nodeid = get_node_id(inode);
1559 req->in.numargs = 1;
1560 req->in.args[0].size = sizeof(*arg);
1561 req->in.args[0].value = arg;
1562 }
1563
1564 static int fuse_getlk(struct file *file, struct file_lock *fl)
1565 {
1566 struct inode *inode = file_inode(file);
1567 struct fuse_conn *fc = get_fuse_conn(inode);
1568 struct fuse_req *req;
1569 struct fuse_lk_out outarg;
1570 int err;
1571
1572 req = fuse_get_req_nopages(fc);
1573 if (IS_ERR(req))
1574 return PTR_ERR(req);
1575
1576 fuse_lk_fill(req, file, fl, FUSE_GETLK, 0, 0);
1577 req->out.numargs = 1;
1578 req->out.args[0].size = sizeof(outarg);
1579 req->out.args[0].value = &outarg;
1580 fuse_request_send(fc, req);
1581 err = req->out.h.error;
1582 fuse_put_request(fc, req);
1583 if (!err)
1584 err = convert_fuse_file_lock(&outarg.lk, fl);
1585
1586 return err;
1587 }
1588
1589 static int fuse_setlk(struct file *file, struct file_lock *fl, int flock)
1590 {
1591 struct inode *inode = file_inode(file);
1592 struct fuse_conn *fc = get_fuse_conn(inode);
1593 struct fuse_req *req;
1594 int opcode = (fl->fl_flags & FL_SLEEP) ? FUSE_SETLKW : FUSE_SETLK;
1595 pid_t pid = fl->fl_type != F_UNLCK ? current->tgid : 0;
1596 int err;
1597
1598 if (fl->fl_lmops && fl->fl_lmops->lm_grant) {
1599 /* NLM needs asynchronous locks, which we don't support yet */
1600 return -ENOLCK;
1601 }
1602
1603 /* Unlock on close is handled by the flush method */
1604 if (fl->fl_flags & FL_CLOSE)
1605 return 0;
1606
1607 req = fuse_get_req_nopages(fc);
1608 if (IS_ERR(req))
1609 return PTR_ERR(req);
1610
1611 fuse_lk_fill(req, file, fl, opcode, pid, flock);
1612 fuse_request_send(fc, req);
1613 err = req->out.h.error;
1614 /* locking is restartable */
1615 if (err == -EINTR)
1616 err = -ERESTARTSYS;
1617 fuse_put_request(fc, req);
1618 return err;
1619 }
1620
1621 static int fuse_file_lock(struct file *file, int cmd, struct file_lock *fl)
1622 {
1623 struct inode *inode = file_inode(file);
1624 struct fuse_conn *fc = get_fuse_conn(inode);
1625 int err;
1626
1627 if (cmd == F_CANCELLK) {
1628 err = 0;
1629 } else if (cmd == F_GETLK) {
1630 if (fc->no_lock) {
1631 posix_test_lock(file, fl);
1632 err = 0;
1633 } else
1634 err = fuse_getlk(file, fl);
1635 } else {
1636 if (fc->no_lock)
1637 err = posix_lock_file(file, fl, NULL);
1638 else
1639 err = fuse_setlk(file, fl, 0);
1640 }
1641 return err;
1642 }
1643
1644 static int fuse_file_flock(struct file *file, int cmd, struct file_lock *fl)
1645 {
1646 struct inode *inode = file_inode(file);
1647 struct fuse_conn *fc = get_fuse_conn(inode);
1648 int err;
1649
1650 if (fc->no_flock) {
1651 err = flock_lock_file_wait(file, fl);
1652 } else {
1653 struct fuse_file *ff = file->private_data;
1654
1655 /* emulate flock with POSIX locks */
1656 fl->fl_owner = (fl_owner_t) file;
1657 ff->flock = true;
1658 err = fuse_setlk(file, fl, 1);
1659 }
1660
1661 return err;
1662 }
1663
1664 static sector_t fuse_bmap(struct address_space *mapping, sector_t block)
1665 {
1666 struct inode *inode = mapping->host;
1667 struct fuse_conn *fc = get_fuse_conn(inode);
1668 struct fuse_req *req;
1669 struct fuse_bmap_in inarg;
1670 struct fuse_bmap_out outarg;
1671 int err;
1672
1673 if (!inode->i_sb->s_bdev || fc->no_bmap)
1674 return 0;
1675
1676 req = fuse_get_req_nopages(fc);
1677 if (IS_ERR(req))
1678 return 0;
1679
1680 memset(&inarg, 0, sizeof(inarg));
1681 inarg.block = block;
1682 inarg.blocksize = inode->i_sb->s_blocksize;
1683 req->in.h.opcode = FUSE_BMAP;
1684 req->in.h.nodeid = get_node_id(inode);
1685 req->in.numargs = 1;
1686 req->in.args[0].size = sizeof(inarg);
1687 req->in.args[0].value = &inarg;
1688 req->out.numargs = 1;
1689 req->out.args[0].size = sizeof(outarg);
1690 req->out.args[0].value = &outarg;
1691 fuse_request_send(fc, req);
1692 err = req->out.h.error;
1693 fuse_put_request(fc, req);
1694 if (err == -ENOSYS)
1695 fc->no_bmap = 1;
1696
1697 return err ? 0 : outarg.block;
1698 }
1699
1700 static loff_t fuse_file_llseek(struct file *file, loff_t offset, int whence)
1701 {
1702 loff_t retval;
1703 struct inode *inode = file_inode(file);
1704
1705 /* No i_mutex protection necessary for SEEK_CUR and SEEK_SET */
1706 if (whence == SEEK_CUR || whence == SEEK_SET)
1707 return generic_file_llseek(file, offset, whence);
1708
1709 mutex_lock(&inode->i_mutex);
1710 retval = fuse_update_attributes(inode, NULL, file, NULL);
1711 if (!retval)
1712 retval = generic_file_llseek(file, offset, whence);
1713 mutex_unlock(&inode->i_mutex);
1714
1715 return retval;
1716 }
1717
1718 static int fuse_ioctl_copy_user(struct page **pages, struct iovec *iov,
1719 unsigned int nr_segs, size_t bytes, bool to_user)
1720 {
1721 struct iov_iter ii;
1722 int page_idx = 0;
1723
1724 if (!bytes)
1725 return 0;
1726
1727 iov_iter_init(&ii, iov, nr_segs, bytes, 0);
1728
1729 while (iov_iter_count(&ii)) {
1730 struct page *page = pages[page_idx++];
1731 size_t todo = min_t(size_t, PAGE_SIZE, iov_iter_count(&ii));
1732 void *kaddr;
1733
1734 kaddr = kmap(page);
1735
1736 while (todo) {
1737 char __user *uaddr = ii.iov->iov_base + ii.iov_offset;
1738 size_t iov_len = ii.iov->iov_len - ii.iov_offset;
1739 size_t copy = min(todo, iov_len);
1740 size_t left;
1741
1742 if (!to_user)
1743 left = copy_from_user(kaddr, uaddr, copy);
1744 else
1745 left = copy_to_user(uaddr, kaddr, copy);
1746
1747 if (unlikely(left))
1748 return -EFAULT;
1749
1750 iov_iter_advance(&ii, copy);
1751 todo -= copy;
1752 kaddr += copy;
1753 }
1754
1755 kunmap(page);
1756 }
1757
1758 return 0;
1759 }
1760
1761 /*
1762 * CUSE servers compiled on 32bit broke on 64bit kernels because the
1763 * ABI was defined to be 'struct iovec' which is different on 32bit
1764 * and 64bit. Fortunately we can determine which structure the server
1765 * used from the size of the reply.
1766 */
1767 static int fuse_copy_ioctl_iovec_old(struct iovec *dst, void *src,
1768 size_t transferred, unsigned count,
1769 bool is_compat)
1770 {
1771 #ifdef CONFIG_COMPAT
1772 if (count * sizeof(struct compat_iovec) == transferred) {
1773 struct compat_iovec *ciov = src;
1774 unsigned i;
1775
1776 /*
1777 * With this interface a 32bit server cannot support
1778 * non-compat (i.e. ones coming from 64bit apps) ioctl
1779 * requests
1780 */
1781 if (!is_compat)
1782 return -EINVAL;
1783
1784 for (i = 0; i < count; i++) {
1785 dst[i].iov_base = compat_ptr(ciov[i].iov_base);
1786 dst[i].iov_len = ciov[i].iov_len;
1787 }
1788 return 0;
1789 }
1790 #endif
1791
1792 if (count * sizeof(struct iovec) != transferred)
1793 return -EIO;
1794
1795 memcpy(dst, src, transferred);
1796 return 0;
1797 }
1798
1799 /* Make sure iov_length() won't overflow */
1800 static int fuse_verify_ioctl_iov(struct iovec *iov, size_t count)
1801 {
1802 size_t n;
1803 u32 max = FUSE_MAX_PAGES_PER_REQ << PAGE_SHIFT;
1804
1805 for (n = 0; n < count; n++, iov++) {
1806 if (iov->iov_len > (size_t) max)
1807 return -ENOMEM;
1808 max -= iov->iov_len;
1809 }
1810 return 0;
1811 }
1812
1813 static int fuse_copy_ioctl_iovec(struct fuse_conn *fc, struct iovec *dst,
1814 void *src, size_t transferred, unsigned count,
1815 bool is_compat)
1816 {
1817 unsigned i;
1818 struct fuse_ioctl_iovec *fiov = src;
1819
1820 if (fc->minor < 16) {
1821 return fuse_copy_ioctl_iovec_old(dst, src, transferred,
1822 count, is_compat);
1823 }
1824
1825 if (count * sizeof(struct fuse_ioctl_iovec) != transferred)
1826 return -EIO;
1827
1828 for (i = 0; i < count; i++) {
1829 /* Did the server supply an inappropriate value? */
1830 if (fiov[i].base != (unsigned long) fiov[i].base ||
1831 fiov[i].len != (unsigned long) fiov[i].len)
1832 return -EIO;
1833
1834 dst[i].iov_base = (void __user *) (unsigned long) fiov[i].base;
1835 dst[i].iov_len = (size_t) fiov[i].len;
1836
1837 #ifdef CONFIG_COMPAT
1838 if (is_compat &&
1839 (ptr_to_compat(dst[i].iov_base) != fiov[i].base ||
1840 (compat_size_t) dst[i].iov_len != fiov[i].len))
1841 return -EIO;
1842 #endif
1843 }
1844
1845 return 0;
1846 }
1847
1848
1849 /*
1850 * For ioctls, there is no generic way to determine how much memory
1851 * needs to be read and/or written. Furthermore, ioctls are allowed
1852 * to dereference the passed pointer, so the parameter requires deep
1853 * copying but FUSE has no idea whatsoever about what to copy in or
1854 * out.
1855 *
1856 * This is solved by allowing FUSE server to retry ioctl with
1857 * necessary in/out iovecs. Let's assume the ioctl implementation
1858 * needs to read in the following structure.
1859 *
1860 * struct a {
1861 * char *buf;
1862 * size_t buflen;
1863 * }
1864 *
1865 * On the first callout to FUSE server, inarg->in_size and
1866 * inarg->out_size will be NULL; then, the server completes the ioctl
1867 * with FUSE_IOCTL_RETRY set in out->flags, out->in_iovs set to 1 and
1868 * the actual iov array to
1869 *
1870 * { { .iov_base = inarg.arg, .iov_len = sizeof(struct a) } }
1871 *
1872 * which tells FUSE to copy in the requested area and retry the ioctl.
1873 * On the second round, the server has access to the structure and
1874 * from that it can tell what to look for next, so on the invocation,
1875 * it sets FUSE_IOCTL_RETRY, out->in_iovs to 2 and iov array to
1876 *
1877 * { { .iov_base = inarg.arg, .iov_len = sizeof(struct a) },
1878 * { .iov_base = a.buf, .iov_len = a.buflen } }
1879 *
1880 * FUSE will copy both struct a and the pointed buffer from the
1881 * process doing the ioctl and retry ioctl with both struct a and the
1882 * buffer.
1883 *
1884 * This time, FUSE server has everything it needs and completes ioctl
1885 * without FUSE_IOCTL_RETRY which finishes the ioctl call.
1886 *
1887 * Copying data out works the same way.
1888 *
1889 * Note that if FUSE_IOCTL_UNRESTRICTED is clear, the kernel
1890 * automatically initializes in and out iovs by decoding @cmd with
1891 * _IOC_* macros and the server is not allowed to request RETRY. This
1892 * limits ioctl data transfers to well-formed ioctls and is the forced
1893 * behavior for all FUSE servers.
1894 */
1895 long fuse_do_ioctl(struct file *file, unsigned int cmd, unsigned long arg,
1896 unsigned int flags)
1897 {
1898 struct fuse_file *ff = file->private_data;
1899 struct fuse_conn *fc = ff->fc;
1900 struct fuse_ioctl_in inarg = {
1901 .fh = ff->fh,
1902 .cmd = cmd,
1903 .arg = arg,
1904 .flags = flags
1905 };
1906 struct fuse_ioctl_out outarg;
1907 struct fuse_req *req = NULL;
1908 struct page **pages = NULL;
1909 struct iovec *iov_page = NULL;
1910 struct iovec *in_iov = NULL, *out_iov = NULL;
1911 unsigned int in_iovs = 0, out_iovs = 0, num_pages = 0, max_pages;
1912 size_t in_size, out_size, transferred;
1913 int err;
1914
1915 #if BITS_PER_LONG == 32
1916 inarg.flags |= FUSE_IOCTL_32BIT;
1917 #else
1918 if (flags & FUSE_IOCTL_COMPAT)
1919 inarg.flags |= FUSE_IOCTL_32BIT;
1920 #endif
1921
1922 /* assume all the iovs returned by client always fits in a page */
1923 BUILD_BUG_ON(sizeof(struct fuse_ioctl_iovec) * FUSE_IOCTL_MAX_IOV > PAGE_SIZE);
1924
1925 err = -ENOMEM;
1926 pages = kcalloc(FUSE_MAX_PAGES_PER_REQ, sizeof(pages[0]), GFP_KERNEL);
1927 iov_page = (struct iovec *) __get_free_page(GFP_KERNEL);
1928 if (!pages || !iov_page)
1929 goto out;
1930
1931 /*
1932 * If restricted, initialize IO parameters as encoded in @cmd.
1933 * RETRY from server is not allowed.
1934 */
1935 if (!(flags & FUSE_IOCTL_UNRESTRICTED)) {
1936 struct iovec *iov = iov_page;
1937
1938 iov->iov_base = (void __user *)arg;
1939 iov->iov_len = _IOC_SIZE(cmd);
1940
1941 if (_IOC_DIR(cmd) & _IOC_WRITE) {
1942 in_iov = iov;
1943 in_iovs = 1;
1944 }
1945
1946 if (_IOC_DIR(cmd) & _IOC_READ) {
1947 out_iov = iov;
1948 out_iovs = 1;
1949 }
1950 }
1951
1952 retry:
1953 inarg.in_size = in_size = iov_length(in_iov, in_iovs);
1954 inarg.out_size = out_size = iov_length(out_iov, out_iovs);
1955
1956 /*
1957 * Out data can be used either for actual out data or iovs,
1958 * make sure there always is at least one page.
1959 */
1960 out_size = max_t(size_t, out_size, PAGE_SIZE);
1961 max_pages = DIV_ROUND_UP(max(in_size, out_size), PAGE_SIZE);
1962
1963 /* make sure there are enough buffer pages and init request with them */
1964 err = -ENOMEM;
1965 if (max_pages > FUSE_MAX_PAGES_PER_REQ)
1966 goto out;
1967 while (num_pages < max_pages) {
1968 pages[num_pages] = alloc_page(GFP_KERNEL | __GFP_HIGHMEM);
1969 if (!pages[num_pages])
1970 goto out;
1971 num_pages++;
1972 }
1973
1974 req = fuse_get_req(fc, num_pages);
1975 if (IS_ERR(req)) {
1976 err = PTR_ERR(req);
1977 req = NULL;
1978 goto out;
1979 }
1980 memcpy(req->pages, pages, sizeof(req->pages[0]) * num_pages);
1981 req->num_pages = num_pages;
1982 fuse_page_descs_length_init(req, 0, req->num_pages);
1983
1984 /* okay, let's send it to the client */
1985 req->in.h.opcode = FUSE_IOCTL;
1986 req->in.h.nodeid = ff->nodeid;
1987 req->in.numargs = 1;
1988 req->in.args[0].size = sizeof(inarg);
1989 req->in.args[0].value = &inarg;
1990 if (in_size) {
1991 req->in.numargs++;
1992 req->in.args[1].size = in_size;
1993 req->in.argpages = 1;
1994
1995 err = fuse_ioctl_copy_user(pages, in_iov, in_iovs, in_size,
1996 false);
1997 if (err)
1998 goto out;
1999 }
2000
2001 req->out.numargs = 2;
2002 req->out.args[0].size = sizeof(outarg);
2003 req->out.args[0].value = &outarg;
2004 req->out.args[1].size = out_size;
2005 req->out.argpages = 1;
2006 req->out.argvar = 1;
2007
2008 fuse_request_send(fc, req);
2009 err = req->out.h.error;
2010 transferred = req->out.args[1].size;
2011 fuse_put_request(fc, req);
2012 req = NULL;
2013 if (err)
2014 goto out;
2015
2016 /* did it ask for retry? */
2017 if (outarg.flags & FUSE_IOCTL_RETRY) {
2018 void *vaddr;
2019
2020 /* no retry if in restricted mode */
2021 err = -EIO;
2022 if (!(flags & FUSE_IOCTL_UNRESTRICTED))
2023 goto out;
2024
2025 in_iovs = outarg.in_iovs;
2026 out_iovs = outarg.out_iovs;
2027
2028 /*
2029 * Make sure things are in boundary, separate checks
2030 * are to protect against overflow.
2031 */
2032 err = -ENOMEM;
2033 if (in_iovs > FUSE_IOCTL_MAX_IOV ||
2034 out_iovs > FUSE_IOCTL_MAX_IOV ||
2035 in_iovs + out_iovs > FUSE_IOCTL_MAX_IOV)
2036 goto out;
2037
2038 vaddr = kmap_atomic(pages[0]);
2039 err = fuse_copy_ioctl_iovec(fc, iov_page, vaddr,
2040 transferred, in_iovs + out_iovs,
2041 (flags & FUSE_IOCTL_COMPAT) != 0);
2042 kunmap_atomic(vaddr);
2043 if (err)
2044 goto out;
2045
2046 in_iov = iov_page;
2047 out_iov = in_iov + in_iovs;
2048
2049 err = fuse_verify_ioctl_iov(in_iov, in_iovs);
2050 if (err)
2051 goto out;
2052
2053 err = fuse_verify_ioctl_iov(out_iov, out_iovs);
2054 if (err)
2055 goto out;
2056
2057 goto retry;
2058 }
2059
2060 err = -EIO;
2061 if (transferred > inarg.out_size)
2062 goto out;
2063
2064 err = fuse_ioctl_copy_user(pages, out_iov, out_iovs, transferred, true);
2065 out:
2066 if (req)
2067 fuse_put_request(fc, req);
2068 free_page((unsigned long) iov_page);
2069 while (num_pages)
2070 __free_page(pages[--num_pages]);
2071 kfree(pages);
2072
2073 return err ? err : outarg.result;
2074 }
2075 EXPORT_SYMBOL_GPL(fuse_do_ioctl);
2076
2077 long fuse_ioctl_common(struct file *file, unsigned int cmd,
2078 unsigned long arg, unsigned int flags)
2079 {
2080 struct inode *inode = file_inode(file);
2081 struct fuse_conn *fc = get_fuse_conn(inode);
2082
2083 if (!fuse_allow_current_process(fc))
2084 return -EACCES;
2085
2086 if (is_bad_inode(inode))
2087 return -EIO;
2088
2089 return fuse_do_ioctl(file, cmd, arg, flags);
2090 }
2091
2092 static long fuse_file_ioctl(struct file *file, unsigned int cmd,
2093 unsigned long arg)
2094 {
2095 return fuse_ioctl_common(file, cmd, arg, 0);
2096 }
2097
2098 static long fuse_file_compat_ioctl(struct file *file, unsigned int cmd,
2099 unsigned long arg)
2100 {
2101 return fuse_ioctl_common(file, cmd, arg, FUSE_IOCTL_COMPAT);
2102 }
2103
2104 /*
2105 * All files which have been polled are linked to RB tree
2106 * fuse_conn->polled_files which is indexed by kh. Walk the tree and
2107 * find the matching one.
2108 */
2109 static struct rb_node **fuse_find_polled_node(struct fuse_conn *fc, u64 kh,
2110 struct rb_node **parent_out)
2111 {
2112 struct rb_node **link = &fc->polled_files.rb_node;
2113 struct rb_node *last = NULL;
2114
2115 while (*link) {
2116 struct fuse_file *ff;
2117
2118 last = *link;
2119 ff = rb_entry(last, struct fuse_file, polled_node);
2120
2121 if (kh < ff->kh)
2122 link = &last->rb_left;
2123 else if (kh > ff->kh)
2124 link = &last->rb_right;
2125 else
2126 return link;
2127 }
2128
2129 if (parent_out)
2130 *parent_out = last;
2131 return link;
2132 }
2133
2134 /*
2135 * The file is about to be polled. Make sure it's on the polled_files
2136 * RB tree. Note that files once added to the polled_files tree are
2137 * not removed before the file is released. This is because a file
2138 * polled once is likely to be polled again.
2139 */
2140 static void fuse_register_polled_file(struct fuse_conn *fc,
2141 struct fuse_file *ff)
2142 {
2143 spin_lock(&fc->lock);
2144 if (RB_EMPTY_NODE(&ff->polled_node)) {
2145 struct rb_node **link, *parent;
2146
2147 link = fuse_find_polled_node(fc, ff->kh, &parent);
2148 BUG_ON(*link);
2149 rb_link_node(&ff->polled_node, parent, link);
2150 rb_insert_color(&ff->polled_node, &fc->polled_files);
2151 }
2152 spin_unlock(&fc->lock);
2153 }
2154
2155 unsigned fuse_file_poll(struct file *file, poll_table *wait)
2156 {
2157 struct fuse_file *ff = file->private_data;
2158 struct fuse_conn *fc = ff->fc;
2159 struct fuse_poll_in inarg = { .fh = ff->fh, .kh = ff->kh };
2160 struct fuse_poll_out outarg;
2161 struct fuse_req *req;
2162 int err;
2163
2164 if (fc->no_poll)
2165 return DEFAULT_POLLMASK;
2166
2167 poll_wait(file, &ff->poll_wait, wait);
2168 inarg.events = (__u32)poll_requested_events(wait);
2169
2170 /*
2171 * Ask for notification iff there's someone waiting for it.
2172 * The client may ignore the flag and always notify.
2173 */
2174 if (waitqueue_active(&ff->poll_wait)) {
2175 inarg.flags |= FUSE_POLL_SCHEDULE_NOTIFY;
2176 fuse_register_polled_file(fc, ff);
2177 }
2178
2179 req = fuse_get_req_nopages(fc);
2180 if (IS_ERR(req))
2181 return POLLERR;
2182
2183 req->in.h.opcode = FUSE_POLL;
2184 req->in.h.nodeid = ff->nodeid;
2185 req->in.numargs = 1;
2186 req->in.args[0].size = sizeof(inarg);
2187 req->in.args[0].value = &inarg;
2188 req->out.numargs = 1;
2189 req->out.args[0].size = sizeof(outarg);
2190 req->out.args[0].value = &outarg;
2191 fuse_request_send(fc, req);
2192 err = req->out.h.error;
2193 fuse_put_request(fc, req);
2194
2195 if (!err)
2196 return outarg.revents;
2197 if (err == -ENOSYS) {
2198 fc->no_poll = 1;
2199 return DEFAULT_POLLMASK;
2200 }
2201 return POLLERR;
2202 }
2203 EXPORT_SYMBOL_GPL(fuse_file_poll);
2204
2205 /*
2206 * This is called from fuse_handle_notify() on FUSE_NOTIFY_POLL and
2207 * wakes up the poll waiters.
2208 */
2209 int fuse_notify_poll_wakeup(struct fuse_conn *fc,
2210 struct fuse_notify_poll_wakeup_out *outarg)
2211 {
2212 u64 kh = outarg->kh;
2213 struct rb_node **link;
2214
2215 spin_lock(&fc->lock);
2216
2217 link = fuse_find_polled_node(fc, kh, NULL);
2218 if (*link) {
2219 struct fuse_file *ff;
2220
2221 ff = rb_entry(*link, struct fuse_file, polled_node);
2222 wake_up_interruptible_sync(&ff->poll_wait);
2223 }
2224
2225 spin_unlock(&fc->lock);
2226 return 0;
2227 }
2228
2229 static ssize_t
2230 fuse_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov,
2231 loff_t offset, unsigned long nr_segs)
2232 {
2233 ssize_t ret = 0;
2234 struct file *file = NULL;
2235 loff_t pos = 0;
2236
2237 file = iocb->ki_filp;
2238 pos = offset;
2239
2240 if (rw == WRITE)
2241 ret = __fuse_direct_write(file, iov, nr_segs, &pos);
2242 else
2243 ret = __fuse_direct_read(file, iov, nr_segs, &pos);
2244
2245 return ret;
2246 }
2247
2248 static long fuse_file_fallocate(struct file *file, int mode, loff_t offset,
2249 loff_t length)
2250 {
2251 struct fuse_file *ff = file->private_data;
2252 struct fuse_conn *fc = ff->fc;
2253 struct fuse_req *req;
2254 struct fuse_fallocate_in inarg = {
2255 .fh = ff->fh,
2256 .offset = offset,
2257 .length = length,
2258 .mode = mode
2259 };
2260 int err;
2261
2262 if (fc->no_fallocate)
2263 return -EOPNOTSUPP;
2264
2265 req = fuse_get_req_nopages(fc);
2266 if (IS_ERR(req))
2267 return PTR_ERR(req);
2268
2269 req->in.h.opcode = FUSE_FALLOCATE;
2270 req->in.h.nodeid = ff->nodeid;
2271 req->in.numargs = 1;
2272 req->in.args[0].size = sizeof(inarg);
2273 req->in.args[0].value = &inarg;
2274 fuse_request_send(fc, req);
2275 err = req->out.h.error;
2276 if (err == -ENOSYS) {
2277 fc->no_fallocate = 1;
2278 err = -EOPNOTSUPP;
2279 }
2280 fuse_put_request(fc, req);
2281
2282 return err;
2283 }
2284
2285 static const struct file_operations fuse_file_operations = {
2286 .llseek = fuse_file_llseek,
2287 .read = do_sync_read,
2288 .aio_read = fuse_file_aio_read,
2289 .write = do_sync_write,
2290 .aio_write = fuse_file_aio_write,
2291 .mmap = fuse_file_mmap,
2292 .open = fuse_open,
2293 .flush = fuse_flush,
2294 .release = fuse_release,
2295 .fsync = fuse_fsync,
2296 .lock = fuse_file_lock,
2297 .flock = fuse_file_flock,
2298 .splice_read = generic_file_splice_read,
2299 .unlocked_ioctl = fuse_file_ioctl,
2300 .compat_ioctl = fuse_file_compat_ioctl,
2301 .poll = fuse_file_poll,
2302 .fallocate = fuse_file_fallocate,
2303 };
2304
2305 static const struct file_operations fuse_direct_io_file_operations = {
2306 .llseek = fuse_file_llseek,
2307 .read = fuse_direct_read,
2308 .write = fuse_direct_write,
2309 .mmap = fuse_direct_mmap,
2310 .open = fuse_open,
2311 .flush = fuse_flush,
2312 .release = fuse_release,
2313 .fsync = fuse_fsync,
2314 .lock = fuse_file_lock,
2315 .flock = fuse_file_flock,
2316 .unlocked_ioctl = fuse_file_ioctl,
2317 .compat_ioctl = fuse_file_compat_ioctl,
2318 .poll = fuse_file_poll,
2319 .fallocate = fuse_file_fallocate,
2320 /* no splice_read */
2321 };
2322
2323 static const struct address_space_operations fuse_file_aops = {
2324 .readpage = fuse_readpage,
2325 .writepage = fuse_writepage,
2326 .launder_page = fuse_launder_page,
2327 .readpages = fuse_readpages,
2328 .set_page_dirty = __set_page_dirty_nobuffers,
2329 .bmap = fuse_bmap,
2330 .direct_IO = fuse_direct_IO,
2331 };
2332
2333 void fuse_init_file_inode(struct inode *inode)
2334 {
2335 inode->i_fop = &fuse_file_operations;
2336 inode->i_data.a_ops = &fuse_file_aops;
2337 }
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