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Merge branch 'for-3.16' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup
[mirror_ubuntu-bionic-kernel.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 #include <linux/module.h>
16 #include <linux/compat.h>
17 #include <linux/swap.h>
18 #include <linux/aio.h>
19 #include <linux/falloc.h>
20
21 static const struct file_operations fuse_direct_io_file_operations;
22
23 static int fuse_send_open(struct fuse_conn *fc, u64 nodeid, struct file *file,
24 int opcode, struct fuse_open_out *outargp)
25 {
26 struct fuse_open_in inarg;
27 struct fuse_req *req;
28 int err;
29
30 req = fuse_get_req_nopages(fc);
31 if (IS_ERR(req))
32 return PTR_ERR(req);
33
34 memset(&inarg, 0, sizeof(inarg));
35 inarg.flags = file->f_flags & ~(O_CREAT | O_EXCL | O_NOCTTY);
36 if (!fc->atomic_o_trunc)
37 inarg.flags &= ~O_TRUNC;
38 req->in.h.opcode = opcode;
39 req->in.h.nodeid = nodeid;
40 req->in.numargs = 1;
41 req->in.args[0].size = sizeof(inarg);
42 req->in.args[0].value = &inarg;
43 req->out.numargs = 1;
44 req->out.args[0].size = sizeof(*outargp);
45 req->out.args[0].value = outargp;
46 fuse_request_send(fc, req);
47 err = req->out.h.error;
48 fuse_put_request(fc, req);
49
50 return err;
51 }
52
53 struct fuse_file *fuse_file_alloc(struct fuse_conn *fc)
54 {
55 struct fuse_file *ff;
56
57 ff = kmalloc(sizeof(struct fuse_file), GFP_KERNEL);
58 if (unlikely(!ff))
59 return NULL;
60
61 ff->fc = fc;
62 ff->reserved_req = fuse_request_alloc(0);
63 if (unlikely(!ff->reserved_req)) {
64 kfree(ff);
65 return NULL;
66 }
67
68 INIT_LIST_HEAD(&ff->write_entry);
69 atomic_set(&ff->count, 0);
70 RB_CLEAR_NODE(&ff->polled_node);
71 init_waitqueue_head(&ff->poll_wait);
72
73 spin_lock(&fc->lock);
74 ff->kh = ++fc->khctr;
75 spin_unlock(&fc->lock);
76
77 return ff;
78 }
79
80 void fuse_file_free(struct fuse_file *ff)
81 {
82 fuse_request_free(ff->reserved_req);
83 kfree(ff);
84 }
85
86 struct fuse_file *fuse_file_get(struct fuse_file *ff)
87 {
88 atomic_inc(&ff->count);
89 return ff;
90 }
91
92 static void fuse_release_async(struct work_struct *work)
93 {
94 struct fuse_req *req;
95 struct fuse_conn *fc;
96 struct path path;
97
98 req = container_of(work, struct fuse_req, misc.release.work);
99 path = req->misc.release.path;
100 fc = get_fuse_conn(path.dentry->d_inode);
101
102 fuse_put_request(fc, req);
103 path_put(&path);
104 }
105
106 static void fuse_release_end(struct fuse_conn *fc, struct fuse_req *req)
107 {
108 if (fc->destroy_req) {
109 /*
110 * If this is a fuseblk mount, then it's possible that
111 * releasing the path will result in releasing the
112 * super block and sending the DESTROY request. If
113 * the server is single threaded, this would hang.
114 * For this reason do the path_put() in a separate
115 * thread.
116 */
117 atomic_inc(&req->count);
118 INIT_WORK(&req->misc.release.work, fuse_release_async);
119 schedule_work(&req->misc.release.work);
120 } else {
121 path_put(&req->misc.release.path);
122 }
123 }
124
125 static void fuse_file_put(struct fuse_file *ff, bool sync)
126 {
127 if (atomic_dec_and_test(&ff->count)) {
128 struct fuse_req *req = ff->reserved_req;
129
130 if (ff->fc->no_open) {
131 /*
132 * Drop the release request when client does not
133 * implement 'open'
134 */
135 req->background = 0;
136 path_put(&req->misc.release.path);
137 fuse_put_request(ff->fc, req);
138 } else if (sync) {
139 req->background = 0;
140 fuse_request_send(ff->fc, req);
141 path_put(&req->misc.release.path);
142 fuse_put_request(ff->fc, req);
143 } else {
144 req->end = fuse_release_end;
145 req->background = 1;
146 fuse_request_send_background(ff->fc, req);
147 }
148 kfree(ff);
149 }
150 }
151
152 int fuse_do_open(struct fuse_conn *fc, u64 nodeid, struct file *file,
153 bool isdir)
154 {
155 struct fuse_file *ff;
156 int opcode = isdir ? FUSE_OPENDIR : FUSE_OPEN;
157
158 ff = fuse_file_alloc(fc);
159 if (!ff)
160 return -ENOMEM;
161
162 ff->fh = 0;
163 ff->open_flags = FOPEN_KEEP_CACHE; /* Default for no-open */
164 if (!fc->no_open || isdir) {
165 struct fuse_open_out outarg;
166 int err;
167
168 err = fuse_send_open(fc, nodeid, file, opcode, &outarg);
169 if (!err) {
170 ff->fh = outarg.fh;
171 ff->open_flags = outarg.open_flags;
172
173 } else if (err != -ENOSYS || isdir) {
174 fuse_file_free(ff);
175 return err;
176 } else {
177 fc->no_open = 1;
178 }
179 }
180
181 if (isdir)
182 ff->open_flags &= ~FOPEN_DIRECT_IO;
183
184 ff->nodeid = nodeid;
185 file->private_data = fuse_file_get(ff);
186
187 return 0;
188 }
189 EXPORT_SYMBOL_GPL(fuse_do_open);
190
191 static void fuse_link_write_file(struct file *file)
192 {
193 struct inode *inode = file_inode(file);
194 struct fuse_conn *fc = get_fuse_conn(inode);
195 struct fuse_inode *fi = get_fuse_inode(inode);
196 struct fuse_file *ff = file->private_data;
197 /*
198 * file may be written through mmap, so chain it onto the
199 * inodes's write_file list
200 */
201 spin_lock(&fc->lock);
202 if (list_empty(&ff->write_entry))
203 list_add(&ff->write_entry, &fi->write_files);
204 spin_unlock(&fc->lock);
205 }
206
207 void fuse_finish_open(struct inode *inode, struct file *file)
208 {
209 struct fuse_file *ff = file->private_data;
210 struct fuse_conn *fc = get_fuse_conn(inode);
211
212 if (ff->open_flags & FOPEN_DIRECT_IO)
213 file->f_op = &fuse_direct_io_file_operations;
214 if (!(ff->open_flags & FOPEN_KEEP_CACHE))
215 invalidate_inode_pages2(inode->i_mapping);
216 if (ff->open_flags & FOPEN_NONSEEKABLE)
217 nonseekable_open(inode, file);
218 if (fc->atomic_o_trunc && (file->f_flags & O_TRUNC)) {
219 struct fuse_inode *fi = get_fuse_inode(inode);
220
221 spin_lock(&fc->lock);
222 fi->attr_version = ++fc->attr_version;
223 i_size_write(inode, 0);
224 spin_unlock(&fc->lock);
225 fuse_invalidate_attr(inode);
226 if (fc->writeback_cache)
227 file_update_time(file);
228 }
229 if ((file->f_mode & FMODE_WRITE) && fc->writeback_cache)
230 fuse_link_write_file(file);
231 }
232
233 int fuse_open_common(struct inode *inode, struct file *file, bool isdir)
234 {
235 struct fuse_conn *fc = get_fuse_conn(inode);
236 int err;
237 bool lock_inode = (file->f_flags & O_TRUNC) &&
238 fc->atomic_o_trunc &&
239 fc->writeback_cache;
240
241 err = generic_file_open(inode, file);
242 if (err)
243 return err;
244
245 if (lock_inode)
246 mutex_lock(&inode->i_mutex);
247
248 err = fuse_do_open(fc, get_node_id(inode), file, isdir);
249
250 if (!err)
251 fuse_finish_open(inode, file);
252
253 if (lock_inode)
254 mutex_unlock(&inode->i_mutex);
255
256 return err;
257 }
258
259 static void fuse_prepare_release(struct fuse_file *ff, int flags, int opcode)
260 {
261 struct fuse_conn *fc = ff->fc;
262 struct fuse_req *req = ff->reserved_req;
263 struct fuse_release_in *inarg = &req->misc.release.in;
264
265 spin_lock(&fc->lock);
266 list_del(&ff->write_entry);
267 if (!RB_EMPTY_NODE(&ff->polled_node))
268 rb_erase(&ff->polled_node, &fc->polled_files);
269 spin_unlock(&fc->lock);
270
271 wake_up_interruptible_all(&ff->poll_wait);
272
273 inarg->fh = ff->fh;
274 inarg->flags = flags;
275 req->in.h.opcode = opcode;
276 req->in.h.nodeid = ff->nodeid;
277 req->in.numargs = 1;
278 req->in.args[0].size = sizeof(struct fuse_release_in);
279 req->in.args[0].value = inarg;
280 }
281
282 void fuse_release_common(struct file *file, int opcode)
283 {
284 struct fuse_file *ff;
285 struct fuse_req *req;
286
287 ff = file->private_data;
288 if (unlikely(!ff))
289 return;
290
291 req = ff->reserved_req;
292 fuse_prepare_release(ff, file->f_flags, opcode);
293
294 if (ff->flock) {
295 struct fuse_release_in *inarg = &req->misc.release.in;
296 inarg->release_flags |= FUSE_RELEASE_FLOCK_UNLOCK;
297 inarg->lock_owner = fuse_lock_owner_id(ff->fc,
298 (fl_owner_t) file);
299 }
300 /* Hold vfsmount and dentry until release is finished */
301 path_get(&file->f_path);
302 req->misc.release.path = file->f_path;
303
304 /*
305 * Normally this will send the RELEASE request, however if
306 * some asynchronous READ or WRITE requests are outstanding,
307 * the sending will be delayed.
308 *
309 * Make the release synchronous if this is a fuseblk mount,
310 * synchronous RELEASE is allowed (and desirable) in this case
311 * because the server can be trusted not to screw up.
312 */
313 fuse_file_put(ff, ff->fc->destroy_req != NULL);
314 }
315
316 static int fuse_open(struct inode *inode, struct file *file)
317 {
318 return fuse_open_common(inode, file, false);
319 }
320
321 static int fuse_release(struct inode *inode, struct file *file)
322 {
323 struct fuse_conn *fc = get_fuse_conn(inode);
324
325 /* see fuse_vma_close() for !writeback_cache case */
326 if (fc->writeback_cache)
327 write_inode_now(inode, 1);
328
329 fuse_release_common(file, FUSE_RELEASE);
330
331 /* return value is ignored by VFS */
332 return 0;
333 }
334
335 void fuse_sync_release(struct fuse_file *ff, int flags)
336 {
337 WARN_ON(atomic_read(&ff->count) > 1);
338 fuse_prepare_release(ff, flags, FUSE_RELEASE);
339 ff->reserved_req->force = 1;
340 ff->reserved_req->background = 0;
341 fuse_request_send(ff->fc, ff->reserved_req);
342 fuse_put_request(ff->fc, ff->reserved_req);
343 kfree(ff);
344 }
345 EXPORT_SYMBOL_GPL(fuse_sync_release);
346
347 /*
348 * Scramble the ID space with XTEA, so that the value of the files_struct
349 * pointer is not exposed to userspace.
350 */
351 u64 fuse_lock_owner_id(struct fuse_conn *fc, fl_owner_t id)
352 {
353 u32 *k = fc->scramble_key;
354 u64 v = (unsigned long) id;
355 u32 v0 = v;
356 u32 v1 = v >> 32;
357 u32 sum = 0;
358 int i;
359
360 for (i = 0; i < 32; i++) {
361 v0 += ((v1 << 4 ^ v1 >> 5) + v1) ^ (sum + k[sum & 3]);
362 sum += 0x9E3779B9;
363 v1 += ((v0 << 4 ^ v0 >> 5) + v0) ^ (sum + k[sum>>11 & 3]);
364 }
365
366 return (u64) v0 + ((u64) v1 << 32);
367 }
368
369 /*
370 * Check if any page in a range is under writeback
371 *
372 * This is currently done by walking the list of writepage requests
373 * for the inode, which can be pretty inefficient.
374 */
375 static bool fuse_range_is_writeback(struct inode *inode, pgoff_t idx_from,
376 pgoff_t idx_to)
377 {
378 struct fuse_conn *fc = get_fuse_conn(inode);
379 struct fuse_inode *fi = get_fuse_inode(inode);
380 struct fuse_req *req;
381 bool found = false;
382
383 spin_lock(&fc->lock);
384 list_for_each_entry(req, &fi->writepages, writepages_entry) {
385 pgoff_t curr_index;
386
387 BUG_ON(req->inode != inode);
388 curr_index = req->misc.write.in.offset >> PAGE_CACHE_SHIFT;
389 if (idx_from < curr_index + req->num_pages &&
390 curr_index <= idx_to) {
391 found = true;
392 break;
393 }
394 }
395 spin_unlock(&fc->lock);
396
397 return found;
398 }
399
400 static inline bool fuse_page_is_writeback(struct inode *inode, pgoff_t index)
401 {
402 return fuse_range_is_writeback(inode, index, index);
403 }
404
405 /*
406 * Wait for page writeback to be completed.
407 *
408 * Since fuse doesn't rely on the VM writeback tracking, this has to
409 * use some other means.
410 */
411 static int fuse_wait_on_page_writeback(struct inode *inode, pgoff_t index)
412 {
413 struct fuse_inode *fi = get_fuse_inode(inode);
414
415 wait_event(fi->page_waitq, !fuse_page_is_writeback(inode, index));
416 return 0;
417 }
418
419 /*
420 * Wait for all pending writepages on the inode to finish.
421 *
422 * This is currently done by blocking further writes with FUSE_NOWRITE
423 * and waiting for all sent writes to complete.
424 *
425 * This must be called under i_mutex, otherwise the FUSE_NOWRITE usage
426 * could conflict with truncation.
427 */
428 static void fuse_sync_writes(struct inode *inode)
429 {
430 fuse_set_nowrite(inode);
431 fuse_release_nowrite(inode);
432 }
433
434 static int fuse_flush(struct file *file, fl_owner_t id)
435 {
436 struct inode *inode = file_inode(file);
437 struct fuse_conn *fc = get_fuse_conn(inode);
438 struct fuse_file *ff = file->private_data;
439 struct fuse_req *req;
440 struct fuse_flush_in inarg;
441 int err;
442
443 if (is_bad_inode(inode))
444 return -EIO;
445
446 if (fc->no_flush)
447 return 0;
448
449 err = write_inode_now(inode, 1);
450 if (err)
451 return err;
452
453 mutex_lock(&inode->i_mutex);
454 fuse_sync_writes(inode);
455 mutex_unlock(&inode->i_mutex);
456
457 req = fuse_get_req_nofail_nopages(fc, file);
458 memset(&inarg, 0, sizeof(inarg));
459 inarg.fh = ff->fh;
460 inarg.lock_owner = fuse_lock_owner_id(fc, id);
461 req->in.h.opcode = FUSE_FLUSH;
462 req->in.h.nodeid = get_node_id(inode);
463 req->in.numargs = 1;
464 req->in.args[0].size = sizeof(inarg);
465 req->in.args[0].value = &inarg;
466 req->force = 1;
467 fuse_request_send(fc, req);
468 err = req->out.h.error;
469 fuse_put_request(fc, req);
470 if (err == -ENOSYS) {
471 fc->no_flush = 1;
472 err = 0;
473 }
474 return err;
475 }
476
477 int fuse_fsync_common(struct file *file, loff_t start, loff_t end,
478 int datasync, int isdir)
479 {
480 struct inode *inode = file->f_mapping->host;
481 struct fuse_conn *fc = get_fuse_conn(inode);
482 struct fuse_file *ff = file->private_data;
483 struct fuse_req *req;
484 struct fuse_fsync_in inarg;
485 int err;
486
487 if (is_bad_inode(inode))
488 return -EIO;
489
490 mutex_lock(&inode->i_mutex);
491
492 /*
493 * Start writeback against all dirty pages of the inode, then
494 * wait for all outstanding writes, before sending the FSYNC
495 * request.
496 */
497 err = filemap_write_and_wait_range(inode->i_mapping, start, end);
498 if (err)
499 goto out;
500
501 fuse_sync_writes(inode);
502 err = sync_inode_metadata(inode, 1);
503 if (err)
504 goto out;
505
506 if ((!isdir && fc->no_fsync) || (isdir && fc->no_fsyncdir))
507 goto out;
508
509 req = fuse_get_req_nopages(fc);
510 if (IS_ERR(req)) {
511 err = PTR_ERR(req);
512 goto out;
513 }
514
515 memset(&inarg, 0, sizeof(inarg));
516 inarg.fh = ff->fh;
517 inarg.fsync_flags = datasync ? 1 : 0;
518 req->in.h.opcode = isdir ? FUSE_FSYNCDIR : FUSE_FSYNC;
519 req->in.h.nodeid = get_node_id(inode);
520 req->in.numargs = 1;
521 req->in.args[0].size = sizeof(inarg);
522 req->in.args[0].value = &inarg;
523 fuse_request_send(fc, req);
524 err = req->out.h.error;
525 fuse_put_request(fc, req);
526 if (err == -ENOSYS) {
527 if (isdir)
528 fc->no_fsyncdir = 1;
529 else
530 fc->no_fsync = 1;
531 err = 0;
532 }
533 out:
534 mutex_unlock(&inode->i_mutex);
535 return err;
536 }
537
538 static int fuse_fsync(struct file *file, loff_t start, loff_t end,
539 int datasync)
540 {
541 return fuse_fsync_common(file, start, end, datasync, 0);
542 }
543
544 void fuse_read_fill(struct fuse_req *req, struct file *file, loff_t pos,
545 size_t count, int opcode)
546 {
547 struct fuse_read_in *inarg = &req->misc.read.in;
548 struct fuse_file *ff = file->private_data;
549
550 inarg->fh = ff->fh;
551 inarg->offset = pos;
552 inarg->size = count;
553 inarg->flags = file->f_flags;
554 req->in.h.opcode = opcode;
555 req->in.h.nodeid = ff->nodeid;
556 req->in.numargs = 1;
557 req->in.args[0].size = sizeof(struct fuse_read_in);
558 req->in.args[0].value = inarg;
559 req->out.argvar = 1;
560 req->out.numargs = 1;
561 req->out.args[0].size = count;
562 }
563
564 static void fuse_release_user_pages(struct fuse_req *req, int write)
565 {
566 unsigned i;
567
568 for (i = 0; i < req->num_pages; i++) {
569 struct page *page = req->pages[i];
570 if (write)
571 set_page_dirty_lock(page);
572 put_page(page);
573 }
574 }
575
576 /**
577 * In case of short read, the caller sets 'pos' to the position of
578 * actual end of fuse request in IO request. Otherwise, if bytes_requested
579 * == bytes_transferred or rw == WRITE, the caller sets 'pos' to -1.
580 *
581 * An example:
582 * User requested DIO read of 64K. It was splitted into two 32K fuse requests,
583 * both submitted asynchronously. The first of them was ACKed by userspace as
584 * fully completed (req->out.args[0].size == 32K) resulting in pos == -1. The
585 * second request was ACKed as short, e.g. only 1K was read, resulting in
586 * pos == 33K.
587 *
588 * Thus, when all fuse requests are completed, the minimal non-negative 'pos'
589 * will be equal to the length of the longest contiguous fragment of
590 * transferred data starting from the beginning of IO request.
591 */
592 static void fuse_aio_complete(struct fuse_io_priv *io, int err, ssize_t pos)
593 {
594 int left;
595
596 spin_lock(&io->lock);
597 if (err)
598 io->err = io->err ? : err;
599 else if (pos >= 0 && (io->bytes < 0 || pos < io->bytes))
600 io->bytes = pos;
601
602 left = --io->reqs;
603 spin_unlock(&io->lock);
604
605 if (!left) {
606 long res;
607
608 if (io->err)
609 res = io->err;
610 else if (io->bytes >= 0 && io->write)
611 res = -EIO;
612 else {
613 res = io->bytes < 0 ? io->size : io->bytes;
614
615 if (!is_sync_kiocb(io->iocb)) {
616 struct inode *inode = file_inode(io->iocb->ki_filp);
617 struct fuse_conn *fc = get_fuse_conn(inode);
618 struct fuse_inode *fi = get_fuse_inode(inode);
619
620 spin_lock(&fc->lock);
621 fi->attr_version = ++fc->attr_version;
622 spin_unlock(&fc->lock);
623 }
624 }
625
626 aio_complete(io->iocb, res, 0);
627 kfree(io);
628 }
629 }
630
631 static void fuse_aio_complete_req(struct fuse_conn *fc, struct fuse_req *req)
632 {
633 struct fuse_io_priv *io = req->io;
634 ssize_t pos = -1;
635
636 fuse_release_user_pages(req, !io->write);
637
638 if (io->write) {
639 if (req->misc.write.in.size != req->misc.write.out.size)
640 pos = req->misc.write.in.offset - io->offset +
641 req->misc.write.out.size;
642 } else {
643 if (req->misc.read.in.size != req->out.args[0].size)
644 pos = req->misc.read.in.offset - io->offset +
645 req->out.args[0].size;
646 }
647
648 fuse_aio_complete(io, req->out.h.error, pos);
649 }
650
651 static size_t fuse_async_req_send(struct fuse_conn *fc, struct fuse_req *req,
652 size_t num_bytes, struct fuse_io_priv *io)
653 {
654 spin_lock(&io->lock);
655 io->size += num_bytes;
656 io->reqs++;
657 spin_unlock(&io->lock);
658
659 req->io = io;
660 req->end = fuse_aio_complete_req;
661
662 __fuse_get_request(req);
663 fuse_request_send_background(fc, req);
664
665 return num_bytes;
666 }
667
668 static size_t fuse_send_read(struct fuse_req *req, struct fuse_io_priv *io,
669 loff_t pos, size_t count, fl_owner_t owner)
670 {
671 struct file *file = io->file;
672 struct fuse_file *ff = file->private_data;
673 struct fuse_conn *fc = ff->fc;
674
675 fuse_read_fill(req, file, pos, count, FUSE_READ);
676 if (owner != NULL) {
677 struct fuse_read_in *inarg = &req->misc.read.in;
678
679 inarg->read_flags |= FUSE_READ_LOCKOWNER;
680 inarg->lock_owner = fuse_lock_owner_id(fc, owner);
681 }
682
683 if (io->async)
684 return fuse_async_req_send(fc, req, count, io);
685
686 fuse_request_send(fc, req);
687 return req->out.args[0].size;
688 }
689
690 static void fuse_read_update_size(struct inode *inode, loff_t size,
691 u64 attr_ver)
692 {
693 struct fuse_conn *fc = get_fuse_conn(inode);
694 struct fuse_inode *fi = get_fuse_inode(inode);
695
696 spin_lock(&fc->lock);
697 if (attr_ver == fi->attr_version && size < inode->i_size &&
698 !test_bit(FUSE_I_SIZE_UNSTABLE, &fi->state)) {
699 fi->attr_version = ++fc->attr_version;
700 i_size_write(inode, size);
701 }
702 spin_unlock(&fc->lock);
703 }
704
705 static void fuse_short_read(struct fuse_req *req, struct inode *inode,
706 u64 attr_ver)
707 {
708 size_t num_read = req->out.args[0].size;
709 struct fuse_conn *fc = get_fuse_conn(inode);
710
711 if (fc->writeback_cache) {
712 /*
713 * A hole in a file. Some data after the hole are in page cache,
714 * but have not reached the client fs yet. So, the hole is not
715 * present there.
716 */
717 int i;
718 int start_idx = num_read >> PAGE_CACHE_SHIFT;
719 size_t off = num_read & (PAGE_CACHE_SIZE - 1);
720
721 for (i = start_idx; i < req->num_pages; i++) {
722 zero_user_segment(req->pages[i], off, PAGE_CACHE_SIZE);
723 off = 0;
724 }
725 } else {
726 loff_t pos = page_offset(req->pages[0]) + num_read;
727 fuse_read_update_size(inode, pos, attr_ver);
728 }
729 }
730
731 static int fuse_do_readpage(struct file *file, struct page *page)
732 {
733 struct fuse_io_priv io = { .async = 0, .file = file };
734 struct inode *inode = page->mapping->host;
735 struct fuse_conn *fc = get_fuse_conn(inode);
736 struct fuse_req *req;
737 size_t num_read;
738 loff_t pos = page_offset(page);
739 size_t count = PAGE_CACHE_SIZE;
740 u64 attr_ver;
741 int err;
742
743 /*
744 * Page writeback can extend beyond the lifetime of the
745 * page-cache page, so make sure we read a properly synced
746 * page.
747 */
748 fuse_wait_on_page_writeback(inode, page->index);
749
750 req = fuse_get_req(fc, 1);
751 if (IS_ERR(req))
752 return PTR_ERR(req);
753
754 attr_ver = fuse_get_attr_version(fc);
755
756 req->out.page_zeroing = 1;
757 req->out.argpages = 1;
758 req->num_pages = 1;
759 req->pages[0] = page;
760 req->page_descs[0].length = count;
761 num_read = fuse_send_read(req, &io, pos, count, NULL);
762 err = req->out.h.error;
763
764 if (!err) {
765 /*
766 * Short read means EOF. If file size is larger, truncate it
767 */
768 if (num_read < count)
769 fuse_short_read(req, inode, attr_ver);
770
771 SetPageUptodate(page);
772 }
773
774 fuse_put_request(fc, req);
775
776 return err;
777 }
778
779 static int fuse_readpage(struct file *file, struct page *page)
780 {
781 struct inode *inode = page->mapping->host;
782 int err;
783
784 err = -EIO;
785 if (is_bad_inode(inode))
786 goto out;
787
788 err = fuse_do_readpage(file, page);
789 fuse_invalidate_atime(inode);
790 out:
791 unlock_page(page);
792 return err;
793 }
794
795 static void fuse_readpages_end(struct fuse_conn *fc, struct fuse_req *req)
796 {
797 int i;
798 size_t count = req->misc.read.in.size;
799 size_t num_read = req->out.args[0].size;
800 struct address_space *mapping = NULL;
801
802 for (i = 0; mapping == NULL && i < req->num_pages; i++)
803 mapping = req->pages[i]->mapping;
804
805 if (mapping) {
806 struct inode *inode = mapping->host;
807
808 /*
809 * Short read means EOF. If file size is larger, truncate it
810 */
811 if (!req->out.h.error && num_read < count)
812 fuse_short_read(req, inode, req->misc.read.attr_ver);
813
814 fuse_invalidate_atime(inode);
815 }
816
817 for (i = 0; i < req->num_pages; i++) {
818 struct page *page = req->pages[i];
819 if (!req->out.h.error)
820 SetPageUptodate(page);
821 else
822 SetPageError(page);
823 unlock_page(page);
824 page_cache_release(page);
825 }
826 if (req->ff)
827 fuse_file_put(req->ff, false);
828 }
829
830 static void fuse_send_readpages(struct fuse_req *req, struct file *file)
831 {
832 struct fuse_file *ff = file->private_data;
833 struct fuse_conn *fc = ff->fc;
834 loff_t pos = page_offset(req->pages[0]);
835 size_t count = req->num_pages << PAGE_CACHE_SHIFT;
836
837 req->out.argpages = 1;
838 req->out.page_zeroing = 1;
839 req->out.page_replace = 1;
840 fuse_read_fill(req, file, pos, count, FUSE_READ);
841 req->misc.read.attr_ver = fuse_get_attr_version(fc);
842 if (fc->async_read) {
843 req->ff = fuse_file_get(ff);
844 req->end = fuse_readpages_end;
845 fuse_request_send_background(fc, req);
846 } else {
847 fuse_request_send(fc, req);
848 fuse_readpages_end(fc, req);
849 fuse_put_request(fc, req);
850 }
851 }
852
853 struct fuse_fill_data {
854 struct fuse_req *req;
855 struct file *file;
856 struct inode *inode;
857 unsigned nr_pages;
858 };
859
860 static int fuse_readpages_fill(void *_data, struct page *page)
861 {
862 struct fuse_fill_data *data = _data;
863 struct fuse_req *req = data->req;
864 struct inode *inode = data->inode;
865 struct fuse_conn *fc = get_fuse_conn(inode);
866
867 fuse_wait_on_page_writeback(inode, page->index);
868
869 if (req->num_pages &&
870 (req->num_pages == FUSE_MAX_PAGES_PER_REQ ||
871 (req->num_pages + 1) * PAGE_CACHE_SIZE > fc->max_read ||
872 req->pages[req->num_pages - 1]->index + 1 != page->index)) {
873 int nr_alloc = min_t(unsigned, data->nr_pages,
874 FUSE_MAX_PAGES_PER_REQ);
875 fuse_send_readpages(req, data->file);
876 if (fc->async_read)
877 req = fuse_get_req_for_background(fc, nr_alloc);
878 else
879 req = fuse_get_req(fc, nr_alloc);
880
881 data->req = req;
882 if (IS_ERR(req)) {
883 unlock_page(page);
884 return PTR_ERR(req);
885 }
886 }
887
888 if (WARN_ON(req->num_pages >= req->max_pages)) {
889 fuse_put_request(fc, req);
890 return -EIO;
891 }
892
893 page_cache_get(page);
894 req->pages[req->num_pages] = page;
895 req->page_descs[req->num_pages].length = PAGE_SIZE;
896 req->num_pages++;
897 data->nr_pages--;
898 return 0;
899 }
900
901 static int fuse_readpages(struct file *file, struct address_space *mapping,
902 struct list_head *pages, unsigned nr_pages)
903 {
904 struct inode *inode = mapping->host;
905 struct fuse_conn *fc = get_fuse_conn(inode);
906 struct fuse_fill_data data;
907 int err;
908 int nr_alloc = min_t(unsigned, nr_pages, FUSE_MAX_PAGES_PER_REQ);
909
910 err = -EIO;
911 if (is_bad_inode(inode))
912 goto out;
913
914 data.file = file;
915 data.inode = inode;
916 if (fc->async_read)
917 data.req = fuse_get_req_for_background(fc, nr_alloc);
918 else
919 data.req = fuse_get_req(fc, nr_alloc);
920 data.nr_pages = nr_pages;
921 err = PTR_ERR(data.req);
922 if (IS_ERR(data.req))
923 goto out;
924
925 err = read_cache_pages(mapping, pages, fuse_readpages_fill, &data);
926 if (!err) {
927 if (data.req->num_pages)
928 fuse_send_readpages(data.req, file);
929 else
930 fuse_put_request(fc, data.req);
931 }
932 out:
933 return err;
934 }
935
936 static ssize_t fuse_file_aio_read(struct kiocb *iocb, const struct iovec *iov,
937 unsigned long nr_segs, loff_t pos)
938 {
939 struct inode *inode = iocb->ki_filp->f_mapping->host;
940 struct fuse_conn *fc = get_fuse_conn(inode);
941
942 /*
943 * In auto invalidate mode, always update attributes on read.
944 * Otherwise, only update if we attempt to read past EOF (to ensure
945 * i_size is up to date).
946 */
947 if (fc->auto_inval_data ||
948 (pos + iov_length(iov, nr_segs) > i_size_read(inode))) {
949 int err;
950 err = fuse_update_attributes(inode, NULL, iocb->ki_filp, NULL);
951 if (err)
952 return err;
953 }
954
955 return generic_file_aio_read(iocb, iov, nr_segs, pos);
956 }
957
958 static void fuse_write_fill(struct fuse_req *req, struct fuse_file *ff,
959 loff_t pos, size_t count)
960 {
961 struct fuse_write_in *inarg = &req->misc.write.in;
962 struct fuse_write_out *outarg = &req->misc.write.out;
963
964 inarg->fh = ff->fh;
965 inarg->offset = pos;
966 inarg->size = count;
967 req->in.h.opcode = FUSE_WRITE;
968 req->in.h.nodeid = ff->nodeid;
969 req->in.numargs = 2;
970 if (ff->fc->minor < 9)
971 req->in.args[0].size = FUSE_COMPAT_WRITE_IN_SIZE;
972 else
973 req->in.args[0].size = sizeof(struct fuse_write_in);
974 req->in.args[0].value = inarg;
975 req->in.args[1].size = count;
976 req->out.numargs = 1;
977 req->out.args[0].size = sizeof(struct fuse_write_out);
978 req->out.args[0].value = outarg;
979 }
980
981 static size_t fuse_send_write(struct fuse_req *req, struct fuse_io_priv *io,
982 loff_t pos, size_t count, fl_owner_t owner)
983 {
984 struct file *file = io->file;
985 struct fuse_file *ff = file->private_data;
986 struct fuse_conn *fc = ff->fc;
987 struct fuse_write_in *inarg = &req->misc.write.in;
988
989 fuse_write_fill(req, ff, pos, count);
990 inarg->flags = file->f_flags;
991 if (owner != NULL) {
992 inarg->write_flags |= FUSE_WRITE_LOCKOWNER;
993 inarg->lock_owner = fuse_lock_owner_id(fc, owner);
994 }
995
996 if (io->async)
997 return fuse_async_req_send(fc, req, count, io);
998
999 fuse_request_send(fc, req);
1000 return req->misc.write.out.size;
1001 }
1002
1003 bool fuse_write_update_size(struct inode *inode, loff_t pos)
1004 {
1005 struct fuse_conn *fc = get_fuse_conn(inode);
1006 struct fuse_inode *fi = get_fuse_inode(inode);
1007 bool ret = false;
1008
1009 spin_lock(&fc->lock);
1010 fi->attr_version = ++fc->attr_version;
1011 if (pos > inode->i_size) {
1012 i_size_write(inode, pos);
1013 ret = true;
1014 }
1015 spin_unlock(&fc->lock);
1016
1017 return ret;
1018 }
1019
1020 static size_t fuse_send_write_pages(struct fuse_req *req, struct file *file,
1021 struct inode *inode, loff_t pos,
1022 size_t count)
1023 {
1024 size_t res;
1025 unsigned offset;
1026 unsigned i;
1027 struct fuse_io_priv io = { .async = 0, .file = file };
1028
1029 for (i = 0; i < req->num_pages; i++)
1030 fuse_wait_on_page_writeback(inode, req->pages[i]->index);
1031
1032 res = fuse_send_write(req, &io, pos, count, NULL);
1033
1034 offset = req->page_descs[0].offset;
1035 count = res;
1036 for (i = 0; i < req->num_pages; i++) {
1037 struct page *page = req->pages[i];
1038
1039 if (!req->out.h.error && !offset && count >= PAGE_CACHE_SIZE)
1040 SetPageUptodate(page);
1041
1042 if (count > PAGE_CACHE_SIZE - offset)
1043 count -= PAGE_CACHE_SIZE - offset;
1044 else
1045 count = 0;
1046 offset = 0;
1047
1048 unlock_page(page);
1049 page_cache_release(page);
1050 }
1051
1052 return res;
1053 }
1054
1055 static ssize_t fuse_fill_write_pages(struct fuse_req *req,
1056 struct address_space *mapping,
1057 struct iov_iter *ii, loff_t pos)
1058 {
1059 struct fuse_conn *fc = get_fuse_conn(mapping->host);
1060 unsigned offset = pos & (PAGE_CACHE_SIZE - 1);
1061 size_t count = 0;
1062 int err;
1063
1064 req->in.argpages = 1;
1065 req->page_descs[0].offset = offset;
1066
1067 do {
1068 size_t tmp;
1069 struct page *page;
1070 pgoff_t index = pos >> PAGE_CACHE_SHIFT;
1071 size_t bytes = min_t(size_t, PAGE_CACHE_SIZE - offset,
1072 iov_iter_count(ii));
1073
1074 bytes = min_t(size_t, bytes, fc->max_write - count);
1075
1076 again:
1077 err = -EFAULT;
1078 if (iov_iter_fault_in_readable(ii, bytes))
1079 break;
1080
1081 err = -ENOMEM;
1082 page = grab_cache_page_write_begin(mapping, index, 0);
1083 if (!page)
1084 break;
1085
1086 if (mapping_writably_mapped(mapping))
1087 flush_dcache_page(page);
1088
1089 tmp = iov_iter_copy_from_user_atomic(page, ii, offset, bytes);
1090 flush_dcache_page(page);
1091
1092 if (!tmp) {
1093 unlock_page(page);
1094 page_cache_release(page);
1095 bytes = min(bytes, iov_iter_single_seg_count(ii));
1096 goto again;
1097 }
1098
1099 err = 0;
1100 req->pages[req->num_pages] = page;
1101 req->page_descs[req->num_pages].length = tmp;
1102 req->num_pages++;
1103
1104 iov_iter_advance(ii, tmp);
1105 count += tmp;
1106 pos += tmp;
1107 offset += tmp;
1108 if (offset == PAGE_CACHE_SIZE)
1109 offset = 0;
1110
1111 if (!fc->big_writes)
1112 break;
1113 } while (iov_iter_count(ii) && count < fc->max_write &&
1114 req->num_pages < req->max_pages && offset == 0);
1115
1116 return count > 0 ? count : err;
1117 }
1118
1119 static inline unsigned fuse_wr_pages(loff_t pos, size_t len)
1120 {
1121 return min_t(unsigned,
1122 ((pos + len - 1) >> PAGE_CACHE_SHIFT) -
1123 (pos >> PAGE_CACHE_SHIFT) + 1,
1124 FUSE_MAX_PAGES_PER_REQ);
1125 }
1126
1127 static ssize_t fuse_perform_write(struct file *file,
1128 struct address_space *mapping,
1129 struct iov_iter *ii, loff_t pos)
1130 {
1131 struct inode *inode = mapping->host;
1132 struct fuse_conn *fc = get_fuse_conn(inode);
1133 struct fuse_inode *fi = get_fuse_inode(inode);
1134 int err = 0;
1135 ssize_t res = 0;
1136
1137 if (is_bad_inode(inode))
1138 return -EIO;
1139
1140 if (inode->i_size < pos + iov_iter_count(ii))
1141 set_bit(FUSE_I_SIZE_UNSTABLE, &fi->state);
1142
1143 do {
1144 struct fuse_req *req;
1145 ssize_t count;
1146 unsigned nr_pages = fuse_wr_pages(pos, iov_iter_count(ii));
1147
1148 req = fuse_get_req(fc, nr_pages);
1149 if (IS_ERR(req)) {
1150 err = PTR_ERR(req);
1151 break;
1152 }
1153
1154 count = fuse_fill_write_pages(req, mapping, ii, pos);
1155 if (count <= 0) {
1156 err = count;
1157 } else {
1158 size_t num_written;
1159
1160 num_written = fuse_send_write_pages(req, file, inode,
1161 pos, count);
1162 err = req->out.h.error;
1163 if (!err) {
1164 res += num_written;
1165 pos += num_written;
1166
1167 /* break out of the loop on short write */
1168 if (num_written != count)
1169 err = -EIO;
1170 }
1171 }
1172 fuse_put_request(fc, req);
1173 } while (!err && iov_iter_count(ii));
1174
1175 if (res > 0)
1176 fuse_write_update_size(inode, pos);
1177
1178 clear_bit(FUSE_I_SIZE_UNSTABLE, &fi->state);
1179 fuse_invalidate_attr(inode);
1180
1181 return res > 0 ? res : err;
1182 }
1183
1184 static ssize_t fuse_file_aio_write(struct kiocb *iocb, const struct iovec *iov,
1185 unsigned long nr_segs, loff_t pos)
1186 {
1187 struct file *file = iocb->ki_filp;
1188 struct address_space *mapping = file->f_mapping;
1189 size_t count = 0;
1190 size_t ocount = 0;
1191 ssize_t written = 0;
1192 ssize_t written_buffered = 0;
1193 struct inode *inode = mapping->host;
1194 ssize_t err;
1195 struct iov_iter i;
1196 loff_t endbyte = 0;
1197
1198 if (get_fuse_conn(inode)->writeback_cache) {
1199 /* Update size (EOF optimization) and mode (SUID clearing) */
1200 err = fuse_update_attributes(mapping->host, NULL, file, NULL);
1201 if (err)
1202 return err;
1203
1204 return generic_file_aio_write(iocb, iov, nr_segs, pos);
1205 }
1206
1207 WARN_ON(iocb->ki_pos != pos);
1208
1209 ocount = 0;
1210 err = generic_segment_checks(iov, &nr_segs, &ocount, VERIFY_READ);
1211 if (err)
1212 return err;
1213
1214 count = ocount;
1215 mutex_lock(&inode->i_mutex);
1216
1217 /* We can write back this queue in page reclaim */
1218 current->backing_dev_info = mapping->backing_dev_info;
1219
1220 err = generic_write_checks(file, &pos, &count, S_ISBLK(inode->i_mode));
1221 if (err)
1222 goto out;
1223
1224 if (count == 0)
1225 goto out;
1226
1227 err = file_remove_suid(file);
1228 if (err)
1229 goto out;
1230
1231 err = file_update_time(file);
1232 if (err)
1233 goto out;
1234
1235 if (file->f_flags & O_DIRECT) {
1236 written = generic_file_direct_write(iocb, iov, &nr_segs, pos,
1237 count, ocount);
1238 if (written < 0 || written == count)
1239 goto out;
1240
1241 pos += written;
1242 count -= written;
1243
1244 iov_iter_init(&i, iov, nr_segs, count, written);
1245 written_buffered = fuse_perform_write(file, mapping, &i, pos);
1246 if (written_buffered < 0) {
1247 err = written_buffered;
1248 goto out;
1249 }
1250 endbyte = pos + written_buffered - 1;
1251
1252 err = filemap_write_and_wait_range(file->f_mapping, pos,
1253 endbyte);
1254 if (err)
1255 goto out;
1256
1257 invalidate_mapping_pages(file->f_mapping,
1258 pos >> PAGE_CACHE_SHIFT,
1259 endbyte >> PAGE_CACHE_SHIFT);
1260
1261 written += written_buffered;
1262 iocb->ki_pos = pos + written_buffered;
1263 } else {
1264 iov_iter_init(&i, iov, nr_segs, count, 0);
1265 written = fuse_perform_write(file, mapping, &i, pos);
1266 if (written >= 0)
1267 iocb->ki_pos = pos + written;
1268 }
1269 out:
1270 current->backing_dev_info = NULL;
1271 mutex_unlock(&inode->i_mutex);
1272
1273 return written ? written : err;
1274 }
1275
1276 static inline void fuse_page_descs_length_init(struct fuse_req *req,
1277 unsigned index, unsigned nr_pages)
1278 {
1279 int i;
1280
1281 for (i = index; i < index + nr_pages; i++)
1282 req->page_descs[i].length = PAGE_SIZE -
1283 req->page_descs[i].offset;
1284 }
1285
1286 static inline unsigned long fuse_get_user_addr(const struct iov_iter *ii)
1287 {
1288 return (unsigned long)ii->iov->iov_base + ii->iov_offset;
1289 }
1290
1291 static inline size_t fuse_get_frag_size(const struct iov_iter *ii,
1292 size_t max_size)
1293 {
1294 return min(iov_iter_single_seg_count(ii), max_size);
1295 }
1296
1297 static int fuse_get_user_pages(struct fuse_req *req, struct iov_iter *ii,
1298 size_t *nbytesp, int write)
1299 {
1300 size_t nbytes = 0; /* # bytes already packed in req */
1301
1302 /* Special case for kernel I/O: can copy directly into the buffer */
1303 if (segment_eq(get_fs(), KERNEL_DS)) {
1304 unsigned long user_addr = fuse_get_user_addr(ii);
1305 size_t frag_size = fuse_get_frag_size(ii, *nbytesp);
1306
1307 if (write)
1308 req->in.args[1].value = (void *) user_addr;
1309 else
1310 req->out.args[0].value = (void *) user_addr;
1311
1312 iov_iter_advance(ii, frag_size);
1313 *nbytesp = frag_size;
1314 return 0;
1315 }
1316
1317 while (nbytes < *nbytesp && req->num_pages < req->max_pages) {
1318 unsigned npages;
1319 unsigned long user_addr = fuse_get_user_addr(ii);
1320 unsigned offset = user_addr & ~PAGE_MASK;
1321 size_t frag_size = fuse_get_frag_size(ii, *nbytesp - nbytes);
1322 int ret;
1323
1324 unsigned n = req->max_pages - req->num_pages;
1325 frag_size = min_t(size_t, frag_size, n << PAGE_SHIFT);
1326
1327 npages = (frag_size + offset + PAGE_SIZE - 1) >> PAGE_SHIFT;
1328 npages = clamp(npages, 1U, n);
1329
1330 ret = get_user_pages_fast(user_addr, npages, !write,
1331 &req->pages[req->num_pages]);
1332 if (ret < 0)
1333 return ret;
1334
1335 npages = ret;
1336 frag_size = min_t(size_t, frag_size,
1337 (npages << PAGE_SHIFT) - offset);
1338 iov_iter_advance(ii, frag_size);
1339
1340 req->page_descs[req->num_pages].offset = offset;
1341 fuse_page_descs_length_init(req, req->num_pages, npages);
1342
1343 req->num_pages += npages;
1344 req->page_descs[req->num_pages - 1].length -=
1345 (npages << PAGE_SHIFT) - offset - frag_size;
1346
1347 nbytes += frag_size;
1348 }
1349
1350 if (write)
1351 req->in.argpages = 1;
1352 else
1353 req->out.argpages = 1;
1354
1355 *nbytesp = nbytes;
1356
1357 return 0;
1358 }
1359
1360 static inline int fuse_iter_npages(const struct iov_iter *ii_p)
1361 {
1362 struct iov_iter ii = *ii_p;
1363 int npages = 0;
1364
1365 while (iov_iter_count(&ii) && npages < FUSE_MAX_PAGES_PER_REQ) {
1366 unsigned long user_addr = fuse_get_user_addr(&ii);
1367 unsigned offset = user_addr & ~PAGE_MASK;
1368 size_t frag_size = iov_iter_single_seg_count(&ii);
1369
1370 npages += (frag_size + offset + PAGE_SIZE - 1) >> PAGE_SHIFT;
1371 iov_iter_advance(&ii, frag_size);
1372 }
1373
1374 return min(npages, FUSE_MAX_PAGES_PER_REQ);
1375 }
1376
1377 ssize_t fuse_direct_io(struct fuse_io_priv *io, const struct iovec *iov,
1378 unsigned long nr_segs, size_t count, loff_t *ppos,
1379 int flags)
1380 {
1381 int write = flags & FUSE_DIO_WRITE;
1382 int cuse = flags & FUSE_DIO_CUSE;
1383 struct file *file = io->file;
1384 struct inode *inode = file->f_mapping->host;
1385 struct fuse_file *ff = file->private_data;
1386 struct fuse_conn *fc = ff->fc;
1387 size_t nmax = write ? fc->max_write : fc->max_read;
1388 loff_t pos = *ppos;
1389 pgoff_t idx_from = pos >> PAGE_CACHE_SHIFT;
1390 pgoff_t idx_to = (pos + count - 1) >> PAGE_CACHE_SHIFT;
1391 ssize_t res = 0;
1392 struct fuse_req *req;
1393 struct iov_iter ii;
1394
1395 iov_iter_init(&ii, iov, nr_segs, count, 0);
1396
1397 if (io->async)
1398 req = fuse_get_req_for_background(fc, fuse_iter_npages(&ii));
1399 else
1400 req = fuse_get_req(fc, fuse_iter_npages(&ii));
1401 if (IS_ERR(req))
1402 return PTR_ERR(req);
1403
1404 if (!cuse && fuse_range_is_writeback(inode, idx_from, idx_to)) {
1405 if (!write)
1406 mutex_lock(&inode->i_mutex);
1407 fuse_sync_writes(inode);
1408 if (!write)
1409 mutex_unlock(&inode->i_mutex);
1410 }
1411
1412 while (count) {
1413 size_t nres;
1414 fl_owner_t owner = current->files;
1415 size_t nbytes = min(count, nmax);
1416 int err = fuse_get_user_pages(req, &ii, &nbytes, write);
1417 if (err) {
1418 res = err;
1419 break;
1420 }
1421
1422 if (write)
1423 nres = fuse_send_write(req, io, pos, nbytes, owner);
1424 else
1425 nres = fuse_send_read(req, io, pos, nbytes, owner);
1426
1427 if (!io->async)
1428 fuse_release_user_pages(req, !write);
1429 if (req->out.h.error) {
1430 if (!res)
1431 res = req->out.h.error;
1432 break;
1433 } else if (nres > nbytes) {
1434 res = -EIO;
1435 break;
1436 }
1437 count -= nres;
1438 res += nres;
1439 pos += nres;
1440 if (nres != nbytes)
1441 break;
1442 if (count) {
1443 fuse_put_request(fc, req);
1444 if (io->async)
1445 req = fuse_get_req_for_background(fc,
1446 fuse_iter_npages(&ii));
1447 else
1448 req = fuse_get_req(fc, fuse_iter_npages(&ii));
1449 if (IS_ERR(req))
1450 break;
1451 }
1452 }
1453 if (!IS_ERR(req))
1454 fuse_put_request(fc, req);
1455 if (res > 0)
1456 *ppos = pos;
1457
1458 return res;
1459 }
1460 EXPORT_SYMBOL_GPL(fuse_direct_io);
1461
1462 static ssize_t __fuse_direct_read(struct fuse_io_priv *io,
1463 const struct iovec *iov,
1464 unsigned long nr_segs, loff_t *ppos,
1465 size_t count)
1466 {
1467 ssize_t res;
1468 struct file *file = io->file;
1469 struct inode *inode = file_inode(file);
1470
1471 if (is_bad_inode(inode))
1472 return -EIO;
1473
1474 res = fuse_direct_io(io, iov, nr_segs, count, ppos, 0);
1475
1476 fuse_invalidate_attr(inode);
1477
1478 return res;
1479 }
1480
1481 static ssize_t fuse_direct_read(struct file *file, char __user *buf,
1482 size_t count, loff_t *ppos)
1483 {
1484 struct fuse_io_priv io = { .async = 0, .file = file };
1485 struct iovec iov = { .iov_base = buf, .iov_len = count };
1486 return __fuse_direct_read(&io, &iov, 1, ppos, count);
1487 }
1488
1489 static ssize_t __fuse_direct_write(struct fuse_io_priv *io,
1490 const struct iovec *iov,
1491 unsigned long nr_segs, loff_t *ppos)
1492 {
1493 struct file *file = io->file;
1494 struct inode *inode = file_inode(file);
1495 size_t count = iov_length(iov, nr_segs);
1496 ssize_t res;
1497
1498 res = generic_write_checks(file, ppos, &count, 0);
1499 if (!res)
1500 res = fuse_direct_io(io, iov, nr_segs, count, ppos,
1501 FUSE_DIO_WRITE);
1502
1503 fuse_invalidate_attr(inode);
1504
1505 return res;
1506 }
1507
1508 static ssize_t fuse_direct_write(struct file *file, const char __user *buf,
1509 size_t count, loff_t *ppos)
1510 {
1511 struct iovec iov = { .iov_base = (void __user *)buf, .iov_len = count };
1512 struct inode *inode = file_inode(file);
1513 ssize_t res;
1514 struct fuse_io_priv io = { .async = 0, .file = file };
1515
1516 if (is_bad_inode(inode))
1517 return -EIO;
1518
1519 /* Don't allow parallel writes to the same file */
1520 mutex_lock(&inode->i_mutex);
1521 res = __fuse_direct_write(&io, &iov, 1, ppos);
1522 if (res > 0)
1523 fuse_write_update_size(inode, *ppos);
1524 mutex_unlock(&inode->i_mutex);
1525
1526 return res;
1527 }
1528
1529 static void fuse_writepage_free(struct fuse_conn *fc, struct fuse_req *req)
1530 {
1531 int i;
1532
1533 for (i = 0; i < req->num_pages; i++)
1534 __free_page(req->pages[i]);
1535
1536 if (req->ff)
1537 fuse_file_put(req->ff, false);
1538 }
1539
1540 static void fuse_writepage_finish(struct fuse_conn *fc, struct fuse_req *req)
1541 {
1542 struct inode *inode = req->inode;
1543 struct fuse_inode *fi = get_fuse_inode(inode);
1544 struct backing_dev_info *bdi = inode->i_mapping->backing_dev_info;
1545 int i;
1546
1547 list_del(&req->writepages_entry);
1548 for (i = 0; i < req->num_pages; i++) {
1549 dec_bdi_stat(bdi, BDI_WRITEBACK);
1550 dec_zone_page_state(req->pages[i], NR_WRITEBACK_TEMP);
1551 bdi_writeout_inc(bdi);
1552 }
1553 wake_up(&fi->page_waitq);
1554 }
1555
1556 /* Called under fc->lock, may release and reacquire it */
1557 static void fuse_send_writepage(struct fuse_conn *fc, struct fuse_req *req,
1558 loff_t size)
1559 __releases(fc->lock)
1560 __acquires(fc->lock)
1561 {
1562 struct fuse_inode *fi = get_fuse_inode(req->inode);
1563 struct fuse_write_in *inarg = &req->misc.write.in;
1564 __u64 data_size = req->num_pages * PAGE_CACHE_SIZE;
1565
1566 if (!fc->connected)
1567 goto out_free;
1568
1569 if (inarg->offset + data_size <= size) {
1570 inarg->size = data_size;
1571 } else if (inarg->offset < size) {
1572 inarg->size = size - inarg->offset;
1573 } else {
1574 /* Got truncated off completely */
1575 goto out_free;
1576 }
1577
1578 req->in.args[1].size = inarg->size;
1579 fi->writectr++;
1580 fuse_request_send_background_locked(fc, req);
1581 return;
1582
1583 out_free:
1584 fuse_writepage_finish(fc, req);
1585 spin_unlock(&fc->lock);
1586 fuse_writepage_free(fc, req);
1587 fuse_put_request(fc, req);
1588 spin_lock(&fc->lock);
1589 }
1590
1591 /*
1592 * If fi->writectr is positive (no truncate or fsync going on) send
1593 * all queued writepage requests.
1594 *
1595 * Called with fc->lock
1596 */
1597 void fuse_flush_writepages(struct inode *inode)
1598 __releases(fc->lock)
1599 __acquires(fc->lock)
1600 {
1601 struct fuse_conn *fc = get_fuse_conn(inode);
1602 struct fuse_inode *fi = get_fuse_inode(inode);
1603 size_t crop = i_size_read(inode);
1604 struct fuse_req *req;
1605
1606 while (fi->writectr >= 0 && !list_empty(&fi->queued_writes)) {
1607 req = list_entry(fi->queued_writes.next, struct fuse_req, list);
1608 list_del_init(&req->list);
1609 fuse_send_writepage(fc, req, crop);
1610 }
1611 }
1612
1613 static void fuse_writepage_end(struct fuse_conn *fc, struct fuse_req *req)
1614 {
1615 struct inode *inode = req->inode;
1616 struct fuse_inode *fi = get_fuse_inode(inode);
1617
1618 mapping_set_error(inode->i_mapping, req->out.h.error);
1619 spin_lock(&fc->lock);
1620 while (req->misc.write.next) {
1621 struct fuse_conn *fc = get_fuse_conn(inode);
1622 struct fuse_write_in *inarg = &req->misc.write.in;
1623 struct fuse_req *next = req->misc.write.next;
1624 req->misc.write.next = next->misc.write.next;
1625 next->misc.write.next = NULL;
1626 next->ff = fuse_file_get(req->ff);
1627 list_add(&next->writepages_entry, &fi->writepages);
1628
1629 /*
1630 * Skip fuse_flush_writepages() to make it easy to crop requests
1631 * based on primary request size.
1632 *
1633 * 1st case (trivial): there are no concurrent activities using
1634 * fuse_set/release_nowrite. Then we're on safe side because
1635 * fuse_flush_writepages() would call fuse_send_writepage()
1636 * anyway.
1637 *
1638 * 2nd case: someone called fuse_set_nowrite and it is waiting
1639 * now for completion of all in-flight requests. This happens
1640 * rarely and no more than once per page, so this should be
1641 * okay.
1642 *
1643 * 3rd case: someone (e.g. fuse_do_setattr()) is in the middle
1644 * of fuse_set_nowrite..fuse_release_nowrite section. The fact
1645 * that fuse_set_nowrite returned implies that all in-flight
1646 * requests were completed along with all of their secondary
1647 * requests. Further primary requests are blocked by negative
1648 * writectr. Hence there cannot be any in-flight requests and
1649 * no invocations of fuse_writepage_end() while we're in
1650 * fuse_set_nowrite..fuse_release_nowrite section.
1651 */
1652 fuse_send_writepage(fc, next, inarg->offset + inarg->size);
1653 }
1654 fi->writectr--;
1655 fuse_writepage_finish(fc, req);
1656 spin_unlock(&fc->lock);
1657 fuse_writepage_free(fc, req);
1658 }
1659
1660 static struct fuse_file *__fuse_write_file_get(struct fuse_conn *fc,
1661 struct fuse_inode *fi)
1662 {
1663 struct fuse_file *ff = NULL;
1664
1665 spin_lock(&fc->lock);
1666 if (!list_empty(&fi->write_files)) {
1667 ff = list_entry(fi->write_files.next, struct fuse_file,
1668 write_entry);
1669 fuse_file_get(ff);
1670 }
1671 spin_unlock(&fc->lock);
1672
1673 return ff;
1674 }
1675
1676 static struct fuse_file *fuse_write_file_get(struct fuse_conn *fc,
1677 struct fuse_inode *fi)
1678 {
1679 struct fuse_file *ff = __fuse_write_file_get(fc, fi);
1680 WARN_ON(!ff);
1681 return ff;
1682 }
1683
1684 int fuse_write_inode(struct inode *inode, struct writeback_control *wbc)
1685 {
1686 struct fuse_conn *fc = get_fuse_conn(inode);
1687 struct fuse_inode *fi = get_fuse_inode(inode);
1688 struct fuse_file *ff;
1689 int err;
1690
1691 ff = __fuse_write_file_get(fc, fi);
1692 err = fuse_flush_times(inode, ff);
1693 if (ff)
1694 fuse_file_put(ff, 0);
1695
1696 return err;
1697 }
1698
1699 static int fuse_writepage_locked(struct page *page)
1700 {
1701 struct address_space *mapping = page->mapping;
1702 struct inode *inode = mapping->host;
1703 struct fuse_conn *fc = get_fuse_conn(inode);
1704 struct fuse_inode *fi = get_fuse_inode(inode);
1705 struct fuse_req *req;
1706 struct page *tmp_page;
1707 int error = -ENOMEM;
1708
1709 set_page_writeback(page);
1710
1711 req = fuse_request_alloc_nofs(1);
1712 if (!req)
1713 goto err;
1714
1715 req->background = 1; /* writeback always goes to bg_queue */
1716 tmp_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
1717 if (!tmp_page)
1718 goto err_free;
1719
1720 error = -EIO;
1721 req->ff = fuse_write_file_get(fc, fi);
1722 if (!req->ff)
1723 goto err_free;
1724
1725 fuse_write_fill(req, req->ff, page_offset(page), 0);
1726
1727 copy_highpage(tmp_page, page);
1728 req->misc.write.in.write_flags |= FUSE_WRITE_CACHE;
1729 req->misc.write.next = NULL;
1730 req->in.argpages = 1;
1731 req->num_pages = 1;
1732 req->pages[0] = tmp_page;
1733 req->page_descs[0].offset = 0;
1734 req->page_descs[0].length = PAGE_SIZE;
1735 req->end = fuse_writepage_end;
1736 req->inode = inode;
1737
1738 inc_bdi_stat(mapping->backing_dev_info, BDI_WRITEBACK);
1739 inc_zone_page_state(tmp_page, NR_WRITEBACK_TEMP);
1740
1741 spin_lock(&fc->lock);
1742 list_add(&req->writepages_entry, &fi->writepages);
1743 list_add_tail(&req->list, &fi->queued_writes);
1744 fuse_flush_writepages(inode);
1745 spin_unlock(&fc->lock);
1746
1747 end_page_writeback(page);
1748
1749 return 0;
1750
1751 err_free:
1752 fuse_request_free(req);
1753 err:
1754 end_page_writeback(page);
1755 return error;
1756 }
1757
1758 static int fuse_writepage(struct page *page, struct writeback_control *wbc)
1759 {
1760 int err;
1761
1762 if (fuse_page_is_writeback(page->mapping->host, page->index)) {
1763 /*
1764 * ->writepages() should be called for sync() and friends. We
1765 * should only get here on direct reclaim and then we are
1766 * allowed to skip a page which is already in flight
1767 */
1768 WARN_ON(wbc->sync_mode == WB_SYNC_ALL);
1769
1770 redirty_page_for_writepage(wbc, page);
1771 return 0;
1772 }
1773
1774 err = fuse_writepage_locked(page);
1775 unlock_page(page);
1776
1777 return err;
1778 }
1779
1780 struct fuse_fill_wb_data {
1781 struct fuse_req *req;
1782 struct fuse_file *ff;
1783 struct inode *inode;
1784 struct page **orig_pages;
1785 };
1786
1787 static void fuse_writepages_send(struct fuse_fill_wb_data *data)
1788 {
1789 struct fuse_req *req = data->req;
1790 struct inode *inode = data->inode;
1791 struct fuse_conn *fc = get_fuse_conn(inode);
1792 struct fuse_inode *fi = get_fuse_inode(inode);
1793 int num_pages = req->num_pages;
1794 int i;
1795
1796 req->ff = fuse_file_get(data->ff);
1797 spin_lock(&fc->lock);
1798 list_add_tail(&req->list, &fi->queued_writes);
1799 fuse_flush_writepages(inode);
1800 spin_unlock(&fc->lock);
1801
1802 for (i = 0; i < num_pages; i++)
1803 end_page_writeback(data->orig_pages[i]);
1804 }
1805
1806 static bool fuse_writepage_in_flight(struct fuse_req *new_req,
1807 struct page *page)
1808 {
1809 struct fuse_conn *fc = get_fuse_conn(new_req->inode);
1810 struct fuse_inode *fi = get_fuse_inode(new_req->inode);
1811 struct fuse_req *tmp;
1812 struct fuse_req *old_req;
1813 bool found = false;
1814 pgoff_t curr_index;
1815
1816 BUG_ON(new_req->num_pages != 0);
1817
1818 spin_lock(&fc->lock);
1819 list_del(&new_req->writepages_entry);
1820 list_for_each_entry(old_req, &fi->writepages, writepages_entry) {
1821 BUG_ON(old_req->inode != new_req->inode);
1822 curr_index = old_req->misc.write.in.offset >> PAGE_CACHE_SHIFT;
1823 if (curr_index <= page->index &&
1824 page->index < curr_index + old_req->num_pages) {
1825 found = true;
1826 break;
1827 }
1828 }
1829 if (!found) {
1830 list_add(&new_req->writepages_entry, &fi->writepages);
1831 goto out_unlock;
1832 }
1833
1834 new_req->num_pages = 1;
1835 for (tmp = old_req; tmp != NULL; tmp = tmp->misc.write.next) {
1836 BUG_ON(tmp->inode != new_req->inode);
1837 curr_index = tmp->misc.write.in.offset >> PAGE_CACHE_SHIFT;
1838 if (tmp->num_pages == 1 &&
1839 curr_index == page->index) {
1840 old_req = tmp;
1841 }
1842 }
1843
1844 if (old_req->num_pages == 1 && (old_req->state == FUSE_REQ_INIT ||
1845 old_req->state == FUSE_REQ_PENDING)) {
1846 struct backing_dev_info *bdi = page->mapping->backing_dev_info;
1847
1848 copy_highpage(old_req->pages[0], page);
1849 spin_unlock(&fc->lock);
1850
1851 dec_bdi_stat(bdi, BDI_WRITEBACK);
1852 dec_zone_page_state(page, NR_WRITEBACK_TEMP);
1853 bdi_writeout_inc(bdi);
1854 fuse_writepage_free(fc, new_req);
1855 fuse_request_free(new_req);
1856 goto out;
1857 } else {
1858 new_req->misc.write.next = old_req->misc.write.next;
1859 old_req->misc.write.next = new_req;
1860 }
1861 out_unlock:
1862 spin_unlock(&fc->lock);
1863 out:
1864 return found;
1865 }
1866
1867 static int fuse_writepages_fill(struct page *page,
1868 struct writeback_control *wbc, void *_data)
1869 {
1870 struct fuse_fill_wb_data *data = _data;
1871 struct fuse_req *req = data->req;
1872 struct inode *inode = data->inode;
1873 struct fuse_conn *fc = get_fuse_conn(inode);
1874 struct page *tmp_page;
1875 bool is_writeback;
1876 int err;
1877
1878 if (!data->ff) {
1879 err = -EIO;
1880 data->ff = fuse_write_file_get(fc, get_fuse_inode(inode));
1881 if (!data->ff)
1882 goto out_unlock;
1883 }
1884
1885 /*
1886 * Being under writeback is unlikely but possible. For example direct
1887 * read to an mmaped fuse file will set the page dirty twice; once when
1888 * the pages are faulted with get_user_pages(), and then after the read
1889 * completed.
1890 */
1891 is_writeback = fuse_page_is_writeback(inode, page->index);
1892
1893 if (req && req->num_pages &&
1894 (is_writeback || req->num_pages == FUSE_MAX_PAGES_PER_REQ ||
1895 (req->num_pages + 1) * PAGE_CACHE_SIZE > fc->max_write ||
1896 data->orig_pages[req->num_pages - 1]->index + 1 != page->index)) {
1897 fuse_writepages_send(data);
1898 data->req = NULL;
1899 }
1900 err = -ENOMEM;
1901 tmp_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
1902 if (!tmp_page)
1903 goto out_unlock;
1904
1905 /*
1906 * The page must not be redirtied until the writeout is completed
1907 * (i.e. userspace has sent a reply to the write request). Otherwise
1908 * there could be more than one temporary page instance for each real
1909 * page.
1910 *
1911 * This is ensured by holding the page lock in page_mkwrite() while
1912 * checking fuse_page_is_writeback(). We already hold the page lock
1913 * since clear_page_dirty_for_io() and keep it held until we add the
1914 * request to the fi->writepages list and increment req->num_pages.
1915 * After this fuse_page_is_writeback() will indicate that the page is
1916 * under writeback, so we can release the page lock.
1917 */
1918 if (data->req == NULL) {
1919 struct fuse_inode *fi = get_fuse_inode(inode);
1920
1921 err = -ENOMEM;
1922 req = fuse_request_alloc_nofs(FUSE_MAX_PAGES_PER_REQ);
1923 if (!req) {
1924 __free_page(tmp_page);
1925 goto out_unlock;
1926 }
1927
1928 fuse_write_fill(req, data->ff, page_offset(page), 0);
1929 req->misc.write.in.write_flags |= FUSE_WRITE_CACHE;
1930 req->misc.write.next = NULL;
1931 req->in.argpages = 1;
1932 req->background = 1;
1933 req->num_pages = 0;
1934 req->end = fuse_writepage_end;
1935 req->inode = inode;
1936
1937 spin_lock(&fc->lock);
1938 list_add(&req->writepages_entry, &fi->writepages);
1939 spin_unlock(&fc->lock);
1940
1941 data->req = req;
1942 }
1943 set_page_writeback(page);
1944
1945 copy_highpage(tmp_page, page);
1946 req->pages[req->num_pages] = tmp_page;
1947 req->page_descs[req->num_pages].offset = 0;
1948 req->page_descs[req->num_pages].length = PAGE_SIZE;
1949
1950 inc_bdi_stat(page->mapping->backing_dev_info, BDI_WRITEBACK);
1951 inc_zone_page_state(tmp_page, NR_WRITEBACK_TEMP);
1952
1953 err = 0;
1954 if (is_writeback && fuse_writepage_in_flight(req, page)) {
1955 end_page_writeback(page);
1956 data->req = NULL;
1957 goto out_unlock;
1958 }
1959 data->orig_pages[req->num_pages] = page;
1960
1961 /*
1962 * Protected by fc->lock against concurrent access by
1963 * fuse_page_is_writeback().
1964 */
1965 spin_lock(&fc->lock);
1966 req->num_pages++;
1967 spin_unlock(&fc->lock);
1968
1969 out_unlock:
1970 unlock_page(page);
1971
1972 return err;
1973 }
1974
1975 static int fuse_writepages(struct address_space *mapping,
1976 struct writeback_control *wbc)
1977 {
1978 struct inode *inode = mapping->host;
1979 struct fuse_fill_wb_data data;
1980 int err;
1981
1982 err = -EIO;
1983 if (is_bad_inode(inode))
1984 goto out;
1985
1986 data.inode = inode;
1987 data.req = NULL;
1988 data.ff = NULL;
1989
1990 err = -ENOMEM;
1991 data.orig_pages = kzalloc(sizeof(struct page *) *
1992 FUSE_MAX_PAGES_PER_REQ,
1993 GFP_NOFS);
1994 if (!data.orig_pages)
1995 goto out;
1996
1997 err = write_cache_pages(mapping, wbc, fuse_writepages_fill, &data);
1998 if (data.req) {
1999 /* Ignore errors if we can write at least one page */
2000 BUG_ON(!data.req->num_pages);
2001 fuse_writepages_send(&data);
2002 err = 0;
2003 }
2004 if (data.ff)
2005 fuse_file_put(data.ff, false);
2006
2007 kfree(data.orig_pages);
2008 out:
2009 return err;
2010 }
2011
2012 /*
2013 * It's worthy to make sure that space is reserved on disk for the write,
2014 * but how to implement it without killing performance need more thinking.
2015 */
2016 static int fuse_write_begin(struct file *file, struct address_space *mapping,
2017 loff_t pos, unsigned len, unsigned flags,
2018 struct page **pagep, void **fsdata)
2019 {
2020 pgoff_t index = pos >> PAGE_CACHE_SHIFT;
2021 struct fuse_conn *fc = get_fuse_conn(file->f_dentry->d_inode);
2022 struct page *page;
2023 loff_t fsize;
2024 int err = -ENOMEM;
2025
2026 WARN_ON(!fc->writeback_cache);
2027
2028 page = grab_cache_page_write_begin(mapping, index, flags);
2029 if (!page)
2030 goto error;
2031
2032 fuse_wait_on_page_writeback(mapping->host, page->index);
2033
2034 if (PageUptodate(page) || len == PAGE_CACHE_SIZE)
2035 goto success;
2036 /*
2037 * Check if the start this page comes after the end of file, in which
2038 * case the readpage can be optimized away.
2039 */
2040 fsize = i_size_read(mapping->host);
2041 if (fsize <= (pos & PAGE_CACHE_MASK)) {
2042 size_t off = pos & ~PAGE_CACHE_MASK;
2043 if (off)
2044 zero_user_segment(page, 0, off);
2045 goto success;
2046 }
2047 err = fuse_do_readpage(file, page);
2048 if (err)
2049 goto cleanup;
2050 success:
2051 *pagep = page;
2052 return 0;
2053
2054 cleanup:
2055 unlock_page(page);
2056 page_cache_release(page);
2057 error:
2058 return err;
2059 }
2060
2061 static int fuse_write_end(struct file *file, struct address_space *mapping,
2062 loff_t pos, unsigned len, unsigned copied,
2063 struct page *page, void *fsdata)
2064 {
2065 struct inode *inode = page->mapping->host;
2066
2067 if (!PageUptodate(page)) {
2068 /* Zero any unwritten bytes at the end of the page */
2069 size_t endoff = (pos + copied) & ~PAGE_CACHE_MASK;
2070 if (endoff)
2071 zero_user_segment(page, endoff, PAGE_CACHE_SIZE);
2072 SetPageUptodate(page);
2073 }
2074
2075 fuse_write_update_size(inode, pos + copied);
2076 set_page_dirty(page);
2077 unlock_page(page);
2078 page_cache_release(page);
2079
2080 return copied;
2081 }
2082
2083 static int fuse_launder_page(struct page *page)
2084 {
2085 int err = 0;
2086 if (clear_page_dirty_for_io(page)) {
2087 struct inode *inode = page->mapping->host;
2088 err = fuse_writepage_locked(page);
2089 if (!err)
2090 fuse_wait_on_page_writeback(inode, page->index);
2091 }
2092 return err;
2093 }
2094
2095 /*
2096 * Write back dirty pages now, because there may not be any suitable
2097 * open files later
2098 */
2099 static void fuse_vma_close(struct vm_area_struct *vma)
2100 {
2101 filemap_write_and_wait(vma->vm_file->f_mapping);
2102 }
2103
2104 /*
2105 * Wait for writeback against this page to complete before allowing it
2106 * to be marked dirty again, and hence written back again, possibly
2107 * before the previous writepage completed.
2108 *
2109 * Block here, instead of in ->writepage(), so that the userspace fs
2110 * can only block processes actually operating on the filesystem.
2111 *
2112 * Otherwise unprivileged userspace fs would be able to block
2113 * unrelated:
2114 *
2115 * - page migration
2116 * - sync(2)
2117 * - try_to_free_pages() with order > PAGE_ALLOC_COSTLY_ORDER
2118 */
2119 static int fuse_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
2120 {
2121 struct page *page = vmf->page;
2122 struct inode *inode = file_inode(vma->vm_file);
2123
2124 file_update_time(vma->vm_file);
2125 lock_page(page);
2126 if (page->mapping != inode->i_mapping) {
2127 unlock_page(page);
2128 return VM_FAULT_NOPAGE;
2129 }
2130
2131 fuse_wait_on_page_writeback(inode, page->index);
2132 return VM_FAULT_LOCKED;
2133 }
2134
2135 static const struct vm_operations_struct fuse_file_vm_ops = {
2136 .close = fuse_vma_close,
2137 .fault = filemap_fault,
2138 .map_pages = filemap_map_pages,
2139 .page_mkwrite = fuse_page_mkwrite,
2140 .remap_pages = generic_file_remap_pages,
2141 };
2142
2143 static int fuse_file_mmap(struct file *file, struct vm_area_struct *vma)
2144 {
2145 if ((vma->vm_flags & VM_SHARED) && (vma->vm_flags & VM_MAYWRITE))
2146 fuse_link_write_file(file);
2147
2148 file_accessed(file);
2149 vma->vm_ops = &fuse_file_vm_ops;
2150 return 0;
2151 }
2152
2153 static int fuse_direct_mmap(struct file *file, struct vm_area_struct *vma)
2154 {
2155 /* Can't provide the coherency needed for MAP_SHARED */
2156 if (vma->vm_flags & VM_MAYSHARE)
2157 return -ENODEV;
2158
2159 invalidate_inode_pages2(file->f_mapping);
2160
2161 return generic_file_mmap(file, vma);
2162 }
2163
2164 static int convert_fuse_file_lock(const struct fuse_file_lock *ffl,
2165 struct file_lock *fl)
2166 {
2167 switch (ffl->type) {
2168 case F_UNLCK:
2169 break;
2170
2171 case F_RDLCK:
2172 case F_WRLCK:
2173 if (ffl->start > OFFSET_MAX || ffl->end > OFFSET_MAX ||
2174 ffl->end < ffl->start)
2175 return -EIO;
2176
2177 fl->fl_start = ffl->start;
2178 fl->fl_end = ffl->end;
2179 fl->fl_pid = ffl->pid;
2180 break;
2181
2182 default:
2183 return -EIO;
2184 }
2185 fl->fl_type = ffl->type;
2186 return 0;
2187 }
2188
2189 static void fuse_lk_fill(struct fuse_req *req, struct file *file,
2190 const struct file_lock *fl, int opcode, pid_t pid,
2191 int flock)
2192 {
2193 struct inode *inode = file_inode(file);
2194 struct fuse_conn *fc = get_fuse_conn(inode);
2195 struct fuse_file *ff = file->private_data;
2196 struct fuse_lk_in *arg = &req->misc.lk_in;
2197
2198 arg->fh = ff->fh;
2199 arg->owner = fuse_lock_owner_id(fc, fl->fl_owner);
2200 arg->lk.start = fl->fl_start;
2201 arg->lk.end = fl->fl_end;
2202 arg->lk.type = fl->fl_type;
2203 arg->lk.pid = pid;
2204 if (flock)
2205 arg->lk_flags |= FUSE_LK_FLOCK;
2206 req->in.h.opcode = opcode;
2207 req->in.h.nodeid = get_node_id(inode);
2208 req->in.numargs = 1;
2209 req->in.args[0].size = sizeof(*arg);
2210 req->in.args[0].value = arg;
2211 }
2212
2213 static int fuse_getlk(struct file *file, struct file_lock *fl)
2214 {
2215 struct inode *inode = file_inode(file);
2216 struct fuse_conn *fc = get_fuse_conn(inode);
2217 struct fuse_req *req;
2218 struct fuse_lk_out outarg;
2219 int err;
2220
2221 req = fuse_get_req_nopages(fc);
2222 if (IS_ERR(req))
2223 return PTR_ERR(req);
2224
2225 fuse_lk_fill(req, file, fl, FUSE_GETLK, 0, 0);
2226 req->out.numargs = 1;
2227 req->out.args[0].size = sizeof(outarg);
2228 req->out.args[0].value = &outarg;
2229 fuse_request_send(fc, req);
2230 err = req->out.h.error;
2231 fuse_put_request(fc, req);
2232 if (!err)
2233 err = convert_fuse_file_lock(&outarg.lk, fl);
2234
2235 return err;
2236 }
2237
2238 static int fuse_setlk(struct file *file, struct file_lock *fl, int flock)
2239 {
2240 struct inode *inode = file_inode(file);
2241 struct fuse_conn *fc = get_fuse_conn(inode);
2242 struct fuse_req *req;
2243 int opcode = (fl->fl_flags & FL_SLEEP) ? FUSE_SETLKW : FUSE_SETLK;
2244 pid_t pid = fl->fl_type != F_UNLCK ? current->tgid : 0;
2245 int err;
2246
2247 if (fl->fl_lmops && fl->fl_lmops->lm_grant) {
2248 /* NLM needs asynchronous locks, which we don't support yet */
2249 return -ENOLCK;
2250 }
2251
2252 /* Unlock on close is handled by the flush method */
2253 if (fl->fl_flags & FL_CLOSE)
2254 return 0;
2255
2256 req = fuse_get_req_nopages(fc);
2257 if (IS_ERR(req))
2258 return PTR_ERR(req);
2259
2260 fuse_lk_fill(req, file, fl, opcode, pid, flock);
2261 fuse_request_send(fc, req);
2262 err = req->out.h.error;
2263 /* locking is restartable */
2264 if (err == -EINTR)
2265 err = -ERESTARTSYS;
2266 fuse_put_request(fc, req);
2267 return err;
2268 }
2269
2270 static int fuse_file_lock(struct file *file, int cmd, struct file_lock *fl)
2271 {
2272 struct inode *inode = file_inode(file);
2273 struct fuse_conn *fc = get_fuse_conn(inode);
2274 int err;
2275
2276 if (cmd == F_CANCELLK) {
2277 err = 0;
2278 } else if (cmd == F_GETLK) {
2279 if (fc->no_lock) {
2280 posix_test_lock(file, fl);
2281 err = 0;
2282 } else
2283 err = fuse_getlk(file, fl);
2284 } else {
2285 if (fc->no_lock)
2286 err = posix_lock_file(file, fl, NULL);
2287 else
2288 err = fuse_setlk(file, fl, 0);
2289 }
2290 return err;
2291 }
2292
2293 static int fuse_file_flock(struct file *file, int cmd, struct file_lock *fl)
2294 {
2295 struct inode *inode = file_inode(file);
2296 struct fuse_conn *fc = get_fuse_conn(inode);
2297 int err;
2298
2299 if (fc->no_flock) {
2300 err = flock_lock_file_wait(file, fl);
2301 } else {
2302 struct fuse_file *ff = file->private_data;
2303
2304 /* emulate flock with POSIX locks */
2305 ff->flock = true;
2306 err = fuse_setlk(file, fl, 1);
2307 }
2308
2309 return err;
2310 }
2311
2312 static sector_t fuse_bmap(struct address_space *mapping, sector_t block)
2313 {
2314 struct inode *inode = mapping->host;
2315 struct fuse_conn *fc = get_fuse_conn(inode);
2316 struct fuse_req *req;
2317 struct fuse_bmap_in inarg;
2318 struct fuse_bmap_out outarg;
2319 int err;
2320
2321 if (!inode->i_sb->s_bdev || fc->no_bmap)
2322 return 0;
2323
2324 req = fuse_get_req_nopages(fc);
2325 if (IS_ERR(req))
2326 return 0;
2327
2328 memset(&inarg, 0, sizeof(inarg));
2329 inarg.block = block;
2330 inarg.blocksize = inode->i_sb->s_blocksize;
2331 req->in.h.opcode = FUSE_BMAP;
2332 req->in.h.nodeid = get_node_id(inode);
2333 req->in.numargs = 1;
2334 req->in.args[0].size = sizeof(inarg);
2335 req->in.args[0].value = &inarg;
2336 req->out.numargs = 1;
2337 req->out.args[0].size = sizeof(outarg);
2338 req->out.args[0].value = &outarg;
2339 fuse_request_send(fc, req);
2340 err = req->out.h.error;
2341 fuse_put_request(fc, req);
2342 if (err == -ENOSYS)
2343 fc->no_bmap = 1;
2344
2345 return err ? 0 : outarg.block;
2346 }
2347
2348 static loff_t fuse_file_llseek(struct file *file, loff_t offset, int whence)
2349 {
2350 loff_t retval;
2351 struct inode *inode = file_inode(file);
2352
2353 /* No i_mutex protection necessary for SEEK_CUR and SEEK_SET */
2354 if (whence == SEEK_CUR || whence == SEEK_SET)
2355 return generic_file_llseek(file, offset, whence);
2356
2357 mutex_lock(&inode->i_mutex);
2358 retval = fuse_update_attributes(inode, NULL, file, NULL);
2359 if (!retval)
2360 retval = generic_file_llseek(file, offset, whence);
2361 mutex_unlock(&inode->i_mutex);
2362
2363 return retval;
2364 }
2365
2366 static int fuse_ioctl_copy_user(struct page **pages, struct iovec *iov,
2367 unsigned int nr_segs, size_t bytes, bool to_user)
2368 {
2369 struct iov_iter ii;
2370 int page_idx = 0;
2371
2372 if (!bytes)
2373 return 0;
2374
2375 iov_iter_init(&ii, iov, nr_segs, bytes, 0);
2376
2377 while (iov_iter_count(&ii)) {
2378 struct page *page = pages[page_idx++];
2379 size_t todo = min_t(size_t, PAGE_SIZE, iov_iter_count(&ii));
2380 void *kaddr;
2381
2382 kaddr = kmap(page);
2383
2384 while (todo) {
2385 char __user *uaddr = ii.iov->iov_base + ii.iov_offset;
2386 size_t iov_len = ii.iov->iov_len - ii.iov_offset;
2387 size_t copy = min(todo, iov_len);
2388 size_t left;
2389
2390 if (!to_user)
2391 left = copy_from_user(kaddr, uaddr, copy);
2392 else
2393 left = copy_to_user(uaddr, kaddr, copy);
2394
2395 if (unlikely(left))
2396 return -EFAULT;
2397
2398 iov_iter_advance(&ii, copy);
2399 todo -= copy;
2400 kaddr += copy;
2401 }
2402
2403 kunmap(page);
2404 }
2405
2406 return 0;
2407 }
2408
2409 /*
2410 * CUSE servers compiled on 32bit broke on 64bit kernels because the
2411 * ABI was defined to be 'struct iovec' which is different on 32bit
2412 * and 64bit. Fortunately we can determine which structure the server
2413 * used from the size of the reply.
2414 */
2415 static int fuse_copy_ioctl_iovec_old(struct iovec *dst, void *src,
2416 size_t transferred, unsigned count,
2417 bool is_compat)
2418 {
2419 #ifdef CONFIG_COMPAT
2420 if (count * sizeof(struct compat_iovec) == transferred) {
2421 struct compat_iovec *ciov = src;
2422 unsigned i;
2423
2424 /*
2425 * With this interface a 32bit server cannot support
2426 * non-compat (i.e. ones coming from 64bit apps) ioctl
2427 * requests
2428 */
2429 if (!is_compat)
2430 return -EINVAL;
2431
2432 for (i = 0; i < count; i++) {
2433 dst[i].iov_base = compat_ptr(ciov[i].iov_base);
2434 dst[i].iov_len = ciov[i].iov_len;
2435 }
2436 return 0;
2437 }
2438 #endif
2439
2440 if (count * sizeof(struct iovec) != transferred)
2441 return -EIO;
2442
2443 memcpy(dst, src, transferred);
2444 return 0;
2445 }
2446
2447 /* Make sure iov_length() won't overflow */
2448 static int fuse_verify_ioctl_iov(struct iovec *iov, size_t count)
2449 {
2450 size_t n;
2451 u32 max = FUSE_MAX_PAGES_PER_REQ << PAGE_SHIFT;
2452
2453 for (n = 0; n < count; n++, iov++) {
2454 if (iov->iov_len > (size_t) max)
2455 return -ENOMEM;
2456 max -= iov->iov_len;
2457 }
2458 return 0;
2459 }
2460
2461 static int fuse_copy_ioctl_iovec(struct fuse_conn *fc, struct iovec *dst,
2462 void *src, size_t transferred, unsigned count,
2463 bool is_compat)
2464 {
2465 unsigned i;
2466 struct fuse_ioctl_iovec *fiov = src;
2467
2468 if (fc->minor < 16) {
2469 return fuse_copy_ioctl_iovec_old(dst, src, transferred,
2470 count, is_compat);
2471 }
2472
2473 if (count * sizeof(struct fuse_ioctl_iovec) != transferred)
2474 return -EIO;
2475
2476 for (i = 0; i < count; i++) {
2477 /* Did the server supply an inappropriate value? */
2478 if (fiov[i].base != (unsigned long) fiov[i].base ||
2479 fiov[i].len != (unsigned long) fiov[i].len)
2480 return -EIO;
2481
2482 dst[i].iov_base = (void __user *) (unsigned long) fiov[i].base;
2483 dst[i].iov_len = (size_t) fiov[i].len;
2484
2485 #ifdef CONFIG_COMPAT
2486 if (is_compat &&
2487 (ptr_to_compat(dst[i].iov_base) != fiov[i].base ||
2488 (compat_size_t) dst[i].iov_len != fiov[i].len))
2489 return -EIO;
2490 #endif
2491 }
2492
2493 return 0;
2494 }
2495
2496
2497 /*
2498 * For ioctls, there is no generic way to determine how much memory
2499 * needs to be read and/or written. Furthermore, ioctls are allowed
2500 * to dereference the passed pointer, so the parameter requires deep
2501 * copying but FUSE has no idea whatsoever about what to copy in or
2502 * out.
2503 *
2504 * This is solved by allowing FUSE server to retry ioctl with
2505 * necessary in/out iovecs. Let's assume the ioctl implementation
2506 * needs to read in the following structure.
2507 *
2508 * struct a {
2509 * char *buf;
2510 * size_t buflen;
2511 * }
2512 *
2513 * On the first callout to FUSE server, inarg->in_size and
2514 * inarg->out_size will be NULL; then, the server completes the ioctl
2515 * with FUSE_IOCTL_RETRY set in out->flags, out->in_iovs set to 1 and
2516 * the actual iov array to
2517 *
2518 * { { .iov_base = inarg.arg, .iov_len = sizeof(struct a) } }
2519 *
2520 * which tells FUSE to copy in the requested area and retry the ioctl.
2521 * On the second round, the server has access to the structure and
2522 * from that it can tell what to look for next, so on the invocation,
2523 * it sets FUSE_IOCTL_RETRY, out->in_iovs to 2 and iov array to
2524 *
2525 * { { .iov_base = inarg.arg, .iov_len = sizeof(struct a) },
2526 * { .iov_base = a.buf, .iov_len = a.buflen } }
2527 *
2528 * FUSE will copy both struct a and the pointed buffer from the
2529 * process doing the ioctl and retry ioctl with both struct a and the
2530 * buffer.
2531 *
2532 * This time, FUSE server has everything it needs and completes ioctl
2533 * without FUSE_IOCTL_RETRY which finishes the ioctl call.
2534 *
2535 * Copying data out works the same way.
2536 *
2537 * Note that if FUSE_IOCTL_UNRESTRICTED is clear, the kernel
2538 * automatically initializes in and out iovs by decoding @cmd with
2539 * _IOC_* macros and the server is not allowed to request RETRY. This
2540 * limits ioctl data transfers to well-formed ioctls and is the forced
2541 * behavior for all FUSE servers.
2542 */
2543 long fuse_do_ioctl(struct file *file, unsigned int cmd, unsigned long arg,
2544 unsigned int flags)
2545 {
2546 struct fuse_file *ff = file->private_data;
2547 struct fuse_conn *fc = ff->fc;
2548 struct fuse_ioctl_in inarg = {
2549 .fh = ff->fh,
2550 .cmd = cmd,
2551 .arg = arg,
2552 .flags = flags
2553 };
2554 struct fuse_ioctl_out outarg;
2555 struct fuse_req *req = NULL;
2556 struct page **pages = NULL;
2557 struct iovec *iov_page = NULL;
2558 struct iovec *in_iov = NULL, *out_iov = NULL;
2559 unsigned int in_iovs = 0, out_iovs = 0, num_pages = 0, max_pages;
2560 size_t in_size, out_size, transferred;
2561 int err;
2562
2563 #if BITS_PER_LONG == 32
2564 inarg.flags |= FUSE_IOCTL_32BIT;
2565 #else
2566 if (flags & FUSE_IOCTL_COMPAT)
2567 inarg.flags |= FUSE_IOCTL_32BIT;
2568 #endif
2569
2570 /* assume all the iovs returned by client always fits in a page */
2571 BUILD_BUG_ON(sizeof(struct fuse_ioctl_iovec) * FUSE_IOCTL_MAX_IOV > PAGE_SIZE);
2572
2573 err = -ENOMEM;
2574 pages = kcalloc(FUSE_MAX_PAGES_PER_REQ, sizeof(pages[0]), GFP_KERNEL);
2575 iov_page = (struct iovec *) __get_free_page(GFP_KERNEL);
2576 if (!pages || !iov_page)
2577 goto out;
2578
2579 /*
2580 * If restricted, initialize IO parameters as encoded in @cmd.
2581 * RETRY from server is not allowed.
2582 */
2583 if (!(flags & FUSE_IOCTL_UNRESTRICTED)) {
2584 struct iovec *iov = iov_page;
2585
2586 iov->iov_base = (void __user *)arg;
2587 iov->iov_len = _IOC_SIZE(cmd);
2588
2589 if (_IOC_DIR(cmd) & _IOC_WRITE) {
2590 in_iov = iov;
2591 in_iovs = 1;
2592 }
2593
2594 if (_IOC_DIR(cmd) & _IOC_READ) {
2595 out_iov = iov;
2596 out_iovs = 1;
2597 }
2598 }
2599
2600 retry:
2601 inarg.in_size = in_size = iov_length(in_iov, in_iovs);
2602 inarg.out_size = out_size = iov_length(out_iov, out_iovs);
2603
2604 /*
2605 * Out data can be used either for actual out data or iovs,
2606 * make sure there always is at least one page.
2607 */
2608 out_size = max_t(size_t, out_size, PAGE_SIZE);
2609 max_pages = DIV_ROUND_UP(max(in_size, out_size), PAGE_SIZE);
2610
2611 /* make sure there are enough buffer pages and init request with them */
2612 err = -ENOMEM;
2613 if (max_pages > FUSE_MAX_PAGES_PER_REQ)
2614 goto out;
2615 while (num_pages < max_pages) {
2616 pages[num_pages] = alloc_page(GFP_KERNEL | __GFP_HIGHMEM);
2617 if (!pages[num_pages])
2618 goto out;
2619 num_pages++;
2620 }
2621
2622 req = fuse_get_req(fc, num_pages);
2623 if (IS_ERR(req)) {
2624 err = PTR_ERR(req);
2625 req = NULL;
2626 goto out;
2627 }
2628 memcpy(req->pages, pages, sizeof(req->pages[0]) * num_pages);
2629 req->num_pages = num_pages;
2630 fuse_page_descs_length_init(req, 0, req->num_pages);
2631
2632 /* okay, let's send it to the client */
2633 req->in.h.opcode = FUSE_IOCTL;
2634 req->in.h.nodeid = ff->nodeid;
2635 req->in.numargs = 1;
2636 req->in.args[0].size = sizeof(inarg);
2637 req->in.args[0].value = &inarg;
2638 if (in_size) {
2639 req->in.numargs++;
2640 req->in.args[1].size = in_size;
2641 req->in.argpages = 1;
2642
2643 err = fuse_ioctl_copy_user(pages, in_iov, in_iovs, in_size,
2644 false);
2645 if (err)
2646 goto out;
2647 }
2648
2649 req->out.numargs = 2;
2650 req->out.args[0].size = sizeof(outarg);
2651 req->out.args[0].value = &outarg;
2652 req->out.args[1].size = out_size;
2653 req->out.argpages = 1;
2654 req->out.argvar = 1;
2655
2656 fuse_request_send(fc, req);
2657 err = req->out.h.error;
2658 transferred = req->out.args[1].size;
2659 fuse_put_request(fc, req);
2660 req = NULL;
2661 if (err)
2662 goto out;
2663
2664 /* did it ask for retry? */
2665 if (outarg.flags & FUSE_IOCTL_RETRY) {
2666 void *vaddr;
2667
2668 /* no retry if in restricted mode */
2669 err = -EIO;
2670 if (!(flags & FUSE_IOCTL_UNRESTRICTED))
2671 goto out;
2672
2673 in_iovs = outarg.in_iovs;
2674 out_iovs = outarg.out_iovs;
2675
2676 /*
2677 * Make sure things are in boundary, separate checks
2678 * are to protect against overflow.
2679 */
2680 err = -ENOMEM;
2681 if (in_iovs > FUSE_IOCTL_MAX_IOV ||
2682 out_iovs > FUSE_IOCTL_MAX_IOV ||
2683 in_iovs + out_iovs > FUSE_IOCTL_MAX_IOV)
2684 goto out;
2685
2686 vaddr = kmap_atomic(pages[0]);
2687 err = fuse_copy_ioctl_iovec(fc, iov_page, vaddr,
2688 transferred, in_iovs + out_iovs,
2689 (flags & FUSE_IOCTL_COMPAT) != 0);
2690 kunmap_atomic(vaddr);
2691 if (err)
2692 goto out;
2693
2694 in_iov = iov_page;
2695 out_iov = in_iov + in_iovs;
2696
2697 err = fuse_verify_ioctl_iov(in_iov, in_iovs);
2698 if (err)
2699 goto out;
2700
2701 err = fuse_verify_ioctl_iov(out_iov, out_iovs);
2702 if (err)
2703 goto out;
2704
2705 goto retry;
2706 }
2707
2708 err = -EIO;
2709 if (transferred > inarg.out_size)
2710 goto out;
2711
2712 err = fuse_ioctl_copy_user(pages, out_iov, out_iovs, transferred, true);
2713 out:
2714 if (req)
2715 fuse_put_request(fc, req);
2716 free_page((unsigned long) iov_page);
2717 while (num_pages)
2718 __free_page(pages[--num_pages]);
2719 kfree(pages);
2720
2721 return err ? err : outarg.result;
2722 }
2723 EXPORT_SYMBOL_GPL(fuse_do_ioctl);
2724
2725 long fuse_ioctl_common(struct file *file, unsigned int cmd,
2726 unsigned long arg, unsigned int flags)
2727 {
2728 struct inode *inode = file_inode(file);
2729 struct fuse_conn *fc = get_fuse_conn(inode);
2730
2731 if (!fuse_allow_current_process(fc))
2732 return -EACCES;
2733
2734 if (is_bad_inode(inode))
2735 return -EIO;
2736
2737 return fuse_do_ioctl(file, cmd, arg, flags);
2738 }
2739
2740 static long fuse_file_ioctl(struct file *file, unsigned int cmd,
2741 unsigned long arg)
2742 {
2743 return fuse_ioctl_common(file, cmd, arg, 0);
2744 }
2745
2746 static long fuse_file_compat_ioctl(struct file *file, unsigned int cmd,
2747 unsigned long arg)
2748 {
2749 return fuse_ioctl_common(file, cmd, arg, FUSE_IOCTL_COMPAT);
2750 }
2751
2752 /*
2753 * All files which have been polled are linked to RB tree
2754 * fuse_conn->polled_files which is indexed by kh. Walk the tree and
2755 * find the matching one.
2756 */
2757 static struct rb_node **fuse_find_polled_node(struct fuse_conn *fc, u64 kh,
2758 struct rb_node **parent_out)
2759 {
2760 struct rb_node **link = &fc->polled_files.rb_node;
2761 struct rb_node *last = NULL;
2762
2763 while (*link) {
2764 struct fuse_file *ff;
2765
2766 last = *link;
2767 ff = rb_entry(last, struct fuse_file, polled_node);
2768
2769 if (kh < ff->kh)
2770 link = &last->rb_left;
2771 else if (kh > ff->kh)
2772 link = &last->rb_right;
2773 else
2774 return link;
2775 }
2776
2777 if (parent_out)
2778 *parent_out = last;
2779 return link;
2780 }
2781
2782 /*
2783 * The file is about to be polled. Make sure it's on the polled_files
2784 * RB tree. Note that files once added to the polled_files tree are
2785 * not removed before the file is released. This is because a file
2786 * polled once is likely to be polled again.
2787 */
2788 static void fuse_register_polled_file(struct fuse_conn *fc,
2789 struct fuse_file *ff)
2790 {
2791 spin_lock(&fc->lock);
2792 if (RB_EMPTY_NODE(&ff->polled_node)) {
2793 struct rb_node **link, *uninitialized_var(parent);
2794
2795 link = fuse_find_polled_node(fc, ff->kh, &parent);
2796 BUG_ON(*link);
2797 rb_link_node(&ff->polled_node, parent, link);
2798 rb_insert_color(&ff->polled_node, &fc->polled_files);
2799 }
2800 spin_unlock(&fc->lock);
2801 }
2802
2803 unsigned fuse_file_poll(struct file *file, poll_table *wait)
2804 {
2805 struct fuse_file *ff = file->private_data;
2806 struct fuse_conn *fc = ff->fc;
2807 struct fuse_poll_in inarg = { .fh = ff->fh, .kh = ff->kh };
2808 struct fuse_poll_out outarg;
2809 struct fuse_req *req;
2810 int err;
2811
2812 if (fc->no_poll)
2813 return DEFAULT_POLLMASK;
2814
2815 poll_wait(file, &ff->poll_wait, wait);
2816 inarg.events = (__u32)poll_requested_events(wait);
2817
2818 /*
2819 * Ask for notification iff there's someone waiting for it.
2820 * The client may ignore the flag and always notify.
2821 */
2822 if (waitqueue_active(&ff->poll_wait)) {
2823 inarg.flags |= FUSE_POLL_SCHEDULE_NOTIFY;
2824 fuse_register_polled_file(fc, ff);
2825 }
2826
2827 req = fuse_get_req_nopages(fc);
2828 if (IS_ERR(req))
2829 return POLLERR;
2830
2831 req->in.h.opcode = FUSE_POLL;
2832 req->in.h.nodeid = ff->nodeid;
2833 req->in.numargs = 1;
2834 req->in.args[0].size = sizeof(inarg);
2835 req->in.args[0].value = &inarg;
2836 req->out.numargs = 1;
2837 req->out.args[0].size = sizeof(outarg);
2838 req->out.args[0].value = &outarg;
2839 fuse_request_send(fc, req);
2840 err = req->out.h.error;
2841 fuse_put_request(fc, req);
2842
2843 if (!err)
2844 return outarg.revents;
2845 if (err == -ENOSYS) {
2846 fc->no_poll = 1;
2847 return DEFAULT_POLLMASK;
2848 }
2849 return POLLERR;
2850 }
2851 EXPORT_SYMBOL_GPL(fuse_file_poll);
2852
2853 /*
2854 * This is called from fuse_handle_notify() on FUSE_NOTIFY_POLL and
2855 * wakes up the poll waiters.
2856 */
2857 int fuse_notify_poll_wakeup(struct fuse_conn *fc,
2858 struct fuse_notify_poll_wakeup_out *outarg)
2859 {
2860 u64 kh = outarg->kh;
2861 struct rb_node **link;
2862
2863 spin_lock(&fc->lock);
2864
2865 link = fuse_find_polled_node(fc, kh, NULL);
2866 if (*link) {
2867 struct fuse_file *ff;
2868
2869 ff = rb_entry(*link, struct fuse_file, polled_node);
2870 wake_up_interruptible_sync(&ff->poll_wait);
2871 }
2872
2873 spin_unlock(&fc->lock);
2874 return 0;
2875 }
2876
2877 static void fuse_do_truncate(struct file *file)
2878 {
2879 struct inode *inode = file->f_mapping->host;
2880 struct iattr attr;
2881
2882 attr.ia_valid = ATTR_SIZE;
2883 attr.ia_size = i_size_read(inode);
2884
2885 attr.ia_file = file;
2886 attr.ia_valid |= ATTR_FILE;
2887
2888 fuse_do_setattr(inode, &attr, file);
2889 }
2890
2891 static inline loff_t fuse_round_up(loff_t off)
2892 {
2893 return round_up(off, FUSE_MAX_PAGES_PER_REQ << PAGE_SHIFT);
2894 }
2895
2896 static ssize_t
2897 fuse_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov,
2898 loff_t offset, unsigned long nr_segs)
2899 {
2900 ssize_t ret = 0;
2901 struct file *file = iocb->ki_filp;
2902 struct fuse_file *ff = file->private_data;
2903 bool async_dio = ff->fc->async_dio;
2904 loff_t pos = 0;
2905 struct inode *inode;
2906 loff_t i_size;
2907 size_t count = iov_length(iov, nr_segs);
2908 struct fuse_io_priv *io;
2909
2910 pos = offset;
2911 inode = file->f_mapping->host;
2912 i_size = i_size_read(inode);
2913
2914 if ((rw == READ) && (offset > i_size))
2915 return 0;
2916
2917 /* optimization for short read */
2918 if (async_dio && rw != WRITE && offset + count > i_size) {
2919 if (offset >= i_size)
2920 return 0;
2921 count = min_t(loff_t, count, fuse_round_up(i_size - offset));
2922 }
2923
2924 io = kmalloc(sizeof(struct fuse_io_priv), GFP_KERNEL);
2925 if (!io)
2926 return -ENOMEM;
2927 spin_lock_init(&io->lock);
2928 io->reqs = 1;
2929 io->bytes = -1;
2930 io->size = 0;
2931 io->offset = offset;
2932 io->write = (rw == WRITE);
2933 io->err = 0;
2934 io->file = file;
2935 /*
2936 * By default, we want to optimize all I/Os with async request
2937 * submission to the client filesystem if supported.
2938 */
2939 io->async = async_dio;
2940 io->iocb = iocb;
2941
2942 /*
2943 * We cannot asynchronously extend the size of a file. We have no method
2944 * to wait on real async I/O requests, so we must submit this request
2945 * synchronously.
2946 */
2947 if (!is_sync_kiocb(iocb) && (offset + count > i_size) && rw == WRITE)
2948 io->async = false;
2949
2950 if (rw == WRITE)
2951 ret = __fuse_direct_write(io, iov, nr_segs, &pos);
2952 else
2953 ret = __fuse_direct_read(io, iov, nr_segs, &pos, count);
2954
2955 if (io->async) {
2956 fuse_aio_complete(io, ret < 0 ? ret : 0, -1);
2957
2958 /* we have a non-extending, async request, so return */
2959 if (!is_sync_kiocb(iocb))
2960 return -EIOCBQUEUED;
2961
2962 ret = wait_on_sync_kiocb(iocb);
2963 } else {
2964 kfree(io);
2965 }
2966
2967 if (rw == WRITE) {
2968 if (ret > 0)
2969 fuse_write_update_size(inode, pos);
2970 else if (ret < 0 && offset + count > i_size)
2971 fuse_do_truncate(file);
2972 }
2973
2974 return ret;
2975 }
2976
2977 static long fuse_file_fallocate(struct file *file, int mode, loff_t offset,
2978 loff_t length)
2979 {
2980 struct fuse_file *ff = file->private_data;
2981 struct inode *inode = file->f_inode;
2982 struct fuse_inode *fi = get_fuse_inode(inode);
2983 struct fuse_conn *fc = ff->fc;
2984 struct fuse_req *req;
2985 struct fuse_fallocate_in inarg = {
2986 .fh = ff->fh,
2987 .offset = offset,
2988 .length = length,
2989 .mode = mode
2990 };
2991 int err;
2992 bool lock_inode = !(mode & FALLOC_FL_KEEP_SIZE) ||
2993 (mode & FALLOC_FL_PUNCH_HOLE);
2994
2995 if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE))
2996 return -EOPNOTSUPP;
2997
2998 if (fc->no_fallocate)
2999 return -EOPNOTSUPP;
3000
3001 if (lock_inode) {
3002 mutex_lock(&inode->i_mutex);
3003 if (mode & FALLOC_FL_PUNCH_HOLE) {
3004 loff_t endbyte = offset + length - 1;
3005 err = filemap_write_and_wait_range(inode->i_mapping,
3006 offset, endbyte);
3007 if (err)
3008 goto out;
3009
3010 fuse_sync_writes(inode);
3011 }
3012 }
3013
3014 if (!(mode & FALLOC_FL_KEEP_SIZE))
3015 set_bit(FUSE_I_SIZE_UNSTABLE, &fi->state);
3016
3017 req = fuse_get_req_nopages(fc);
3018 if (IS_ERR(req)) {
3019 err = PTR_ERR(req);
3020 goto out;
3021 }
3022
3023 req->in.h.opcode = FUSE_FALLOCATE;
3024 req->in.h.nodeid = ff->nodeid;
3025 req->in.numargs = 1;
3026 req->in.args[0].size = sizeof(inarg);
3027 req->in.args[0].value = &inarg;
3028 fuse_request_send(fc, req);
3029 err = req->out.h.error;
3030 if (err == -ENOSYS) {
3031 fc->no_fallocate = 1;
3032 err = -EOPNOTSUPP;
3033 }
3034 fuse_put_request(fc, req);
3035
3036 if (err)
3037 goto out;
3038
3039 /* we could have extended the file */
3040 if (!(mode & FALLOC_FL_KEEP_SIZE)) {
3041 bool changed = fuse_write_update_size(inode, offset + length);
3042
3043 if (changed && fc->writeback_cache)
3044 file_update_time(file);
3045 }
3046
3047 if (mode & FALLOC_FL_PUNCH_HOLE)
3048 truncate_pagecache_range(inode, offset, offset + length - 1);
3049
3050 fuse_invalidate_attr(inode);
3051
3052 out:
3053 if (!(mode & FALLOC_FL_KEEP_SIZE))
3054 clear_bit(FUSE_I_SIZE_UNSTABLE, &fi->state);
3055
3056 if (lock_inode)
3057 mutex_unlock(&inode->i_mutex);
3058
3059 return err;
3060 }
3061
3062 static const struct file_operations fuse_file_operations = {
3063 .llseek = fuse_file_llseek,
3064 .read = do_sync_read,
3065 .aio_read = fuse_file_aio_read,
3066 .write = do_sync_write,
3067 .aio_write = fuse_file_aio_write,
3068 .mmap = fuse_file_mmap,
3069 .open = fuse_open,
3070 .flush = fuse_flush,
3071 .release = fuse_release,
3072 .fsync = fuse_fsync,
3073 .lock = fuse_file_lock,
3074 .flock = fuse_file_flock,
3075 .splice_read = generic_file_splice_read,
3076 .unlocked_ioctl = fuse_file_ioctl,
3077 .compat_ioctl = fuse_file_compat_ioctl,
3078 .poll = fuse_file_poll,
3079 .fallocate = fuse_file_fallocate,
3080 };
3081
3082 static const struct file_operations fuse_direct_io_file_operations = {
3083 .llseek = fuse_file_llseek,
3084 .read = fuse_direct_read,
3085 .write = fuse_direct_write,
3086 .mmap = fuse_direct_mmap,
3087 .open = fuse_open,
3088 .flush = fuse_flush,
3089 .release = fuse_release,
3090 .fsync = fuse_fsync,
3091 .lock = fuse_file_lock,
3092 .flock = fuse_file_flock,
3093 .unlocked_ioctl = fuse_file_ioctl,
3094 .compat_ioctl = fuse_file_compat_ioctl,
3095 .poll = fuse_file_poll,
3096 .fallocate = fuse_file_fallocate,
3097 /* no splice_read */
3098 };
3099
3100 static const struct address_space_operations fuse_file_aops = {
3101 .readpage = fuse_readpage,
3102 .writepage = fuse_writepage,
3103 .writepages = fuse_writepages,
3104 .launder_page = fuse_launder_page,
3105 .readpages = fuse_readpages,
3106 .set_page_dirty = __set_page_dirty_nobuffers,
3107 .bmap = fuse_bmap,
3108 .direct_IO = fuse_direct_IO,
3109 .write_begin = fuse_write_begin,
3110 .write_end = fuse_write_end,
3111 };
3112
3113 void fuse_init_file_inode(struct inode *inode)
3114 {
3115 inode->i_fop = &fuse_file_operations;
3116 inode->i_data.a_ops = &fuse_file_aops;
3117 }
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