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[mirror_ubuntu-artful-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 mark_page_accessed(page);
1093
1094 if (!tmp) {
1095 unlock_page(page);
1096 page_cache_release(page);
1097 bytes = min(bytes, iov_iter_single_seg_count(ii));
1098 goto again;
1099 }
1100
1101 err = 0;
1102 req->pages[req->num_pages] = page;
1103 req->page_descs[req->num_pages].length = tmp;
1104 req->num_pages++;
1105
1106 iov_iter_advance(ii, tmp);
1107 count += tmp;
1108 pos += tmp;
1109 offset += tmp;
1110 if (offset == PAGE_CACHE_SIZE)
1111 offset = 0;
1112
1113 if (!fc->big_writes)
1114 break;
1115 } while (iov_iter_count(ii) && count < fc->max_write &&
1116 req->num_pages < req->max_pages && offset == 0);
1117
1118 return count > 0 ? count : err;
1119 }
1120
1121 static inline unsigned fuse_wr_pages(loff_t pos, size_t len)
1122 {
1123 return min_t(unsigned,
1124 ((pos + len - 1) >> PAGE_CACHE_SHIFT) -
1125 (pos >> PAGE_CACHE_SHIFT) + 1,
1126 FUSE_MAX_PAGES_PER_REQ);
1127 }
1128
1129 static ssize_t fuse_perform_write(struct file *file,
1130 struct address_space *mapping,
1131 struct iov_iter *ii, loff_t pos)
1132 {
1133 struct inode *inode = mapping->host;
1134 struct fuse_conn *fc = get_fuse_conn(inode);
1135 struct fuse_inode *fi = get_fuse_inode(inode);
1136 int err = 0;
1137 ssize_t res = 0;
1138
1139 if (is_bad_inode(inode))
1140 return -EIO;
1141
1142 if (inode->i_size < pos + iov_iter_count(ii))
1143 set_bit(FUSE_I_SIZE_UNSTABLE, &fi->state);
1144
1145 do {
1146 struct fuse_req *req;
1147 ssize_t count;
1148 unsigned nr_pages = fuse_wr_pages(pos, iov_iter_count(ii));
1149
1150 req = fuse_get_req(fc, nr_pages);
1151 if (IS_ERR(req)) {
1152 err = PTR_ERR(req);
1153 break;
1154 }
1155
1156 count = fuse_fill_write_pages(req, mapping, ii, pos);
1157 if (count <= 0) {
1158 err = count;
1159 } else {
1160 size_t num_written;
1161
1162 num_written = fuse_send_write_pages(req, file, inode,
1163 pos, count);
1164 err = req->out.h.error;
1165 if (!err) {
1166 res += num_written;
1167 pos += num_written;
1168
1169 /* break out of the loop on short write */
1170 if (num_written != count)
1171 err = -EIO;
1172 }
1173 }
1174 fuse_put_request(fc, req);
1175 } while (!err && iov_iter_count(ii));
1176
1177 if (res > 0)
1178 fuse_write_update_size(inode, pos);
1179
1180 clear_bit(FUSE_I_SIZE_UNSTABLE, &fi->state);
1181 fuse_invalidate_attr(inode);
1182
1183 return res > 0 ? res : err;
1184 }
1185
1186 static ssize_t fuse_file_aio_write(struct kiocb *iocb, const struct iovec *iov,
1187 unsigned long nr_segs, loff_t pos)
1188 {
1189 struct file *file = iocb->ki_filp;
1190 struct address_space *mapping = file->f_mapping;
1191 size_t count = 0;
1192 size_t ocount = 0;
1193 ssize_t written = 0;
1194 ssize_t written_buffered = 0;
1195 struct inode *inode = mapping->host;
1196 ssize_t err;
1197 struct iov_iter i;
1198 loff_t endbyte = 0;
1199
1200 if (get_fuse_conn(inode)->writeback_cache) {
1201 /* Update size (EOF optimization) and mode (SUID clearing) */
1202 err = fuse_update_attributes(mapping->host, NULL, file, NULL);
1203 if (err)
1204 return err;
1205
1206 return generic_file_aio_write(iocb, iov, nr_segs, pos);
1207 }
1208
1209 WARN_ON(iocb->ki_pos != pos);
1210
1211 count = ocount = iov_length(iov, nr_segs);
1212 mutex_lock(&inode->i_mutex);
1213
1214 /* We can write back this queue in page reclaim */
1215 current->backing_dev_info = mapping->backing_dev_info;
1216
1217 err = generic_write_checks(file, &pos, &count, S_ISBLK(inode->i_mode));
1218 if (err)
1219 goto out;
1220 iov_iter_init(&i, WRITE, iov, nr_segs, count);
1221
1222 if (count == 0)
1223 goto out;
1224
1225 err = file_remove_suid(file);
1226 if (err)
1227 goto out;
1228
1229 err = file_update_time(file);
1230 if (err)
1231 goto out;
1232
1233 if (file->f_flags & O_DIRECT) {
1234 written = generic_file_direct_write(iocb, &i, pos, count, ocount);
1235 if (written < 0 || written == count)
1236 goto out;
1237
1238 pos += written;
1239
1240 written_buffered = fuse_perform_write(file, mapping, &i, pos);
1241 if (written_buffered < 0) {
1242 err = written_buffered;
1243 goto out;
1244 }
1245 endbyte = pos + written_buffered - 1;
1246
1247 err = filemap_write_and_wait_range(file->f_mapping, pos,
1248 endbyte);
1249 if (err)
1250 goto out;
1251
1252 invalidate_mapping_pages(file->f_mapping,
1253 pos >> PAGE_CACHE_SHIFT,
1254 endbyte >> PAGE_CACHE_SHIFT);
1255
1256 written += written_buffered;
1257 iocb->ki_pos = pos + written_buffered;
1258 } else {
1259 written = fuse_perform_write(file, mapping, &i, pos);
1260 if (written >= 0)
1261 iocb->ki_pos = pos + written;
1262 }
1263 out:
1264 current->backing_dev_info = NULL;
1265 mutex_unlock(&inode->i_mutex);
1266
1267 return written ? written : err;
1268 }
1269
1270 static inline void fuse_page_descs_length_init(struct fuse_req *req,
1271 unsigned index, unsigned nr_pages)
1272 {
1273 int i;
1274
1275 for (i = index; i < index + nr_pages; i++)
1276 req->page_descs[i].length = PAGE_SIZE -
1277 req->page_descs[i].offset;
1278 }
1279
1280 static inline unsigned long fuse_get_user_addr(const struct iov_iter *ii)
1281 {
1282 return (unsigned long)ii->iov->iov_base + ii->iov_offset;
1283 }
1284
1285 static inline size_t fuse_get_frag_size(const struct iov_iter *ii,
1286 size_t max_size)
1287 {
1288 return min(iov_iter_single_seg_count(ii), max_size);
1289 }
1290
1291 static int fuse_get_user_pages(struct fuse_req *req, struct iov_iter *ii,
1292 size_t *nbytesp, int write)
1293 {
1294 size_t nbytes = 0; /* # bytes already packed in req */
1295
1296 /* Special case for kernel I/O: can copy directly into the buffer */
1297 if (ii->type & REQ_KERNEL) {
1298 unsigned long user_addr = fuse_get_user_addr(ii);
1299 size_t frag_size = fuse_get_frag_size(ii, *nbytesp);
1300
1301 if (write)
1302 req->in.args[1].value = (void *) user_addr;
1303 else
1304 req->out.args[0].value = (void *) user_addr;
1305
1306 iov_iter_advance(ii, frag_size);
1307 *nbytesp = frag_size;
1308 return 0;
1309 }
1310
1311 while (nbytes < *nbytesp && req->num_pages < req->max_pages) {
1312 unsigned npages;
1313 size_t start;
1314 unsigned n = req->max_pages - req->num_pages;
1315 ssize_t ret = iov_iter_get_pages(ii,
1316 &req->pages[req->num_pages],
1317 n * PAGE_SIZE, &start);
1318 if (ret < 0)
1319 return ret;
1320
1321 iov_iter_advance(ii, ret);
1322 nbytes += ret;
1323
1324 ret += start;
1325 npages = (ret + PAGE_SIZE - 1) / PAGE_SIZE;
1326
1327 req->page_descs[req->num_pages].offset = start;
1328 fuse_page_descs_length_init(req, req->num_pages, npages);
1329
1330 req->num_pages += npages;
1331 req->page_descs[req->num_pages - 1].length -=
1332 (PAGE_SIZE - ret) & (PAGE_SIZE - 1);
1333 }
1334
1335 if (write)
1336 req->in.argpages = 1;
1337 else
1338 req->out.argpages = 1;
1339
1340 *nbytesp = nbytes;
1341
1342 return 0;
1343 }
1344
1345 static inline int fuse_iter_npages(const struct iov_iter *ii_p)
1346 {
1347 return iov_iter_npages(ii_p, FUSE_MAX_PAGES_PER_REQ);
1348 }
1349
1350 ssize_t fuse_direct_io(struct fuse_io_priv *io, struct iov_iter *iter,
1351 loff_t *ppos, int flags)
1352 {
1353 int write = flags & FUSE_DIO_WRITE;
1354 int cuse = flags & FUSE_DIO_CUSE;
1355 struct file *file = io->file;
1356 struct inode *inode = file->f_mapping->host;
1357 struct fuse_file *ff = file->private_data;
1358 struct fuse_conn *fc = ff->fc;
1359 size_t nmax = write ? fc->max_write : fc->max_read;
1360 loff_t pos = *ppos;
1361 size_t count = iov_iter_count(iter);
1362 pgoff_t idx_from = pos >> PAGE_CACHE_SHIFT;
1363 pgoff_t idx_to = (pos + count - 1) >> PAGE_CACHE_SHIFT;
1364 ssize_t res = 0;
1365 struct fuse_req *req;
1366
1367 if (io->async)
1368 req = fuse_get_req_for_background(fc, fuse_iter_npages(iter));
1369 else
1370 req = fuse_get_req(fc, fuse_iter_npages(iter));
1371 if (IS_ERR(req))
1372 return PTR_ERR(req);
1373
1374 if (!cuse && fuse_range_is_writeback(inode, idx_from, idx_to)) {
1375 if (!write)
1376 mutex_lock(&inode->i_mutex);
1377 fuse_sync_writes(inode);
1378 if (!write)
1379 mutex_unlock(&inode->i_mutex);
1380 }
1381
1382 while (count) {
1383 size_t nres;
1384 fl_owner_t owner = current->files;
1385 size_t nbytes = min(count, nmax);
1386 int err = fuse_get_user_pages(req, iter, &nbytes, write);
1387 if (err) {
1388 res = err;
1389 break;
1390 }
1391
1392 if (write)
1393 nres = fuse_send_write(req, io, pos, nbytes, owner);
1394 else
1395 nres = fuse_send_read(req, io, pos, nbytes, owner);
1396
1397 if (!io->async)
1398 fuse_release_user_pages(req, !write);
1399 if (req->out.h.error) {
1400 if (!res)
1401 res = req->out.h.error;
1402 break;
1403 } else if (nres > nbytes) {
1404 res = -EIO;
1405 break;
1406 }
1407 count -= nres;
1408 res += nres;
1409 pos += nres;
1410 if (nres != nbytes)
1411 break;
1412 if (count) {
1413 fuse_put_request(fc, req);
1414 if (io->async)
1415 req = fuse_get_req_for_background(fc,
1416 fuse_iter_npages(iter));
1417 else
1418 req = fuse_get_req(fc, fuse_iter_npages(iter));
1419 if (IS_ERR(req))
1420 break;
1421 }
1422 }
1423 if (!IS_ERR(req))
1424 fuse_put_request(fc, req);
1425 if (res > 0)
1426 *ppos = pos;
1427
1428 return res;
1429 }
1430 EXPORT_SYMBOL_GPL(fuse_direct_io);
1431
1432 static ssize_t __fuse_direct_read(struct fuse_io_priv *io,
1433 struct iov_iter *iter,
1434 loff_t *ppos)
1435 {
1436 ssize_t res;
1437 struct file *file = io->file;
1438 struct inode *inode = file_inode(file);
1439
1440 if (is_bad_inode(inode))
1441 return -EIO;
1442
1443 res = fuse_direct_io(io, iter, ppos, 0);
1444
1445 fuse_invalidate_attr(inode);
1446
1447 return res;
1448 }
1449
1450 static ssize_t fuse_direct_read(struct file *file, char __user *buf,
1451 size_t count, loff_t *ppos)
1452 {
1453 struct fuse_io_priv io = { .async = 0, .file = file };
1454 struct iovec iov = { .iov_base = buf, .iov_len = count };
1455 struct iov_iter ii;
1456 iov_iter_init(&ii, READ, &iov, 1, count);
1457 return __fuse_direct_read(&io, &ii, ppos);
1458 }
1459
1460 static ssize_t __fuse_direct_write(struct fuse_io_priv *io,
1461 struct iov_iter *iter,
1462 loff_t *ppos)
1463 {
1464 struct file *file = io->file;
1465 struct inode *inode = file_inode(file);
1466 size_t count = iov_iter_count(iter);
1467 ssize_t res;
1468
1469
1470 res = generic_write_checks(file, ppos, &count, 0);
1471 if (!res) {
1472 if (iter->count > count)
1473 iter->count = count;
1474 res = fuse_direct_io(io, iter, ppos, FUSE_DIO_WRITE);
1475 }
1476
1477 fuse_invalidate_attr(inode);
1478
1479 return res;
1480 }
1481
1482 static ssize_t fuse_direct_write(struct file *file, const char __user *buf,
1483 size_t count, loff_t *ppos)
1484 {
1485 struct iovec iov = { .iov_base = (void __user *)buf, .iov_len = count };
1486 struct inode *inode = file_inode(file);
1487 ssize_t res;
1488 struct fuse_io_priv io = { .async = 0, .file = file };
1489 struct iov_iter ii;
1490 iov_iter_init(&ii, WRITE, &iov, 1, count);
1491
1492 if (is_bad_inode(inode))
1493 return -EIO;
1494
1495 /* Don't allow parallel writes to the same file */
1496 mutex_lock(&inode->i_mutex);
1497 res = __fuse_direct_write(&io, &ii, ppos);
1498 if (res > 0)
1499 fuse_write_update_size(inode, *ppos);
1500 mutex_unlock(&inode->i_mutex);
1501
1502 return res;
1503 }
1504
1505 static void fuse_writepage_free(struct fuse_conn *fc, struct fuse_req *req)
1506 {
1507 int i;
1508
1509 for (i = 0; i < req->num_pages; i++)
1510 __free_page(req->pages[i]);
1511
1512 if (req->ff)
1513 fuse_file_put(req->ff, false);
1514 }
1515
1516 static void fuse_writepage_finish(struct fuse_conn *fc, struct fuse_req *req)
1517 {
1518 struct inode *inode = req->inode;
1519 struct fuse_inode *fi = get_fuse_inode(inode);
1520 struct backing_dev_info *bdi = inode->i_mapping->backing_dev_info;
1521 int i;
1522
1523 list_del(&req->writepages_entry);
1524 for (i = 0; i < req->num_pages; i++) {
1525 dec_bdi_stat(bdi, BDI_WRITEBACK);
1526 dec_zone_page_state(req->pages[i], NR_WRITEBACK_TEMP);
1527 bdi_writeout_inc(bdi);
1528 }
1529 wake_up(&fi->page_waitq);
1530 }
1531
1532 /* Called under fc->lock, may release and reacquire it */
1533 static void fuse_send_writepage(struct fuse_conn *fc, struct fuse_req *req,
1534 loff_t size)
1535 __releases(fc->lock)
1536 __acquires(fc->lock)
1537 {
1538 struct fuse_inode *fi = get_fuse_inode(req->inode);
1539 struct fuse_write_in *inarg = &req->misc.write.in;
1540 __u64 data_size = req->num_pages * PAGE_CACHE_SIZE;
1541
1542 if (!fc->connected)
1543 goto out_free;
1544
1545 if (inarg->offset + data_size <= size) {
1546 inarg->size = data_size;
1547 } else if (inarg->offset < size) {
1548 inarg->size = size - inarg->offset;
1549 } else {
1550 /* Got truncated off completely */
1551 goto out_free;
1552 }
1553
1554 req->in.args[1].size = inarg->size;
1555 fi->writectr++;
1556 fuse_request_send_background_locked(fc, req);
1557 return;
1558
1559 out_free:
1560 fuse_writepage_finish(fc, req);
1561 spin_unlock(&fc->lock);
1562 fuse_writepage_free(fc, req);
1563 fuse_put_request(fc, req);
1564 spin_lock(&fc->lock);
1565 }
1566
1567 /*
1568 * If fi->writectr is positive (no truncate or fsync going on) send
1569 * all queued writepage requests.
1570 *
1571 * Called with fc->lock
1572 */
1573 void fuse_flush_writepages(struct inode *inode)
1574 __releases(fc->lock)
1575 __acquires(fc->lock)
1576 {
1577 struct fuse_conn *fc = get_fuse_conn(inode);
1578 struct fuse_inode *fi = get_fuse_inode(inode);
1579 size_t crop = i_size_read(inode);
1580 struct fuse_req *req;
1581
1582 while (fi->writectr >= 0 && !list_empty(&fi->queued_writes)) {
1583 req = list_entry(fi->queued_writes.next, struct fuse_req, list);
1584 list_del_init(&req->list);
1585 fuse_send_writepage(fc, req, crop);
1586 }
1587 }
1588
1589 static void fuse_writepage_end(struct fuse_conn *fc, struct fuse_req *req)
1590 {
1591 struct inode *inode = req->inode;
1592 struct fuse_inode *fi = get_fuse_inode(inode);
1593
1594 mapping_set_error(inode->i_mapping, req->out.h.error);
1595 spin_lock(&fc->lock);
1596 while (req->misc.write.next) {
1597 struct fuse_conn *fc = get_fuse_conn(inode);
1598 struct fuse_write_in *inarg = &req->misc.write.in;
1599 struct fuse_req *next = req->misc.write.next;
1600 req->misc.write.next = next->misc.write.next;
1601 next->misc.write.next = NULL;
1602 next->ff = fuse_file_get(req->ff);
1603 list_add(&next->writepages_entry, &fi->writepages);
1604
1605 /*
1606 * Skip fuse_flush_writepages() to make it easy to crop requests
1607 * based on primary request size.
1608 *
1609 * 1st case (trivial): there are no concurrent activities using
1610 * fuse_set/release_nowrite. Then we're on safe side because
1611 * fuse_flush_writepages() would call fuse_send_writepage()
1612 * anyway.
1613 *
1614 * 2nd case: someone called fuse_set_nowrite and it is waiting
1615 * now for completion of all in-flight requests. This happens
1616 * rarely and no more than once per page, so this should be
1617 * okay.
1618 *
1619 * 3rd case: someone (e.g. fuse_do_setattr()) is in the middle
1620 * of fuse_set_nowrite..fuse_release_nowrite section. The fact
1621 * that fuse_set_nowrite returned implies that all in-flight
1622 * requests were completed along with all of their secondary
1623 * requests. Further primary requests are blocked by negative
1624 * writectr. Hence there cannot be any in-flight requests and
1625 * no invocations of fuse_writepage_end() while we're in
1626 * fuse_set_nowrite..fuse_release_nowrite section.
1627 */
1628 fuse_send_writepage(fc, next, inarg->offset + inarg->size);
1629 }
1630 fi->writectr--;
1631 fuse_writepage_finish(fc, req);
1632 spin_unlock(&fc->lock);
1633 fuse_writepage_free(fc, req);
1634 }
1635
1636 static struct fuse_file *__fuse_write_file_get(struct fuse_conn *fc,
1637 struct fuse_inode *fi)
1638 {
1639 struct fuse_file *ff = NULL;
1640
1641 spin_lock(&fc->lock);
1642 if (!list_empty(&fi->write_files)) {
1643 ff = list_entry(fi->write_files.next, struct fuse_file,
1644 write_entry);
1645 fuse_file_get(ff);
1646 }
1647 spin_unlock(&fc->lock);
1648
1649 return ff;
1650 }
1651
1652 static struct fuse_file *fuse_write_file_get(struct fuse_conn *fc,
1653 struct fuse_inode *fi)
1654 {
1655 struct fuse_file *ff = __fuse_write_file_get(fc, fi);
1656 WARN_ON(!ff);
1657 return ff;
1658 }
1659
1660 int fuse_write_inode(struct inode *inode, struct writeback_control *wbc)
1661 {
1662 struct fuse_conn *fc = get_fuse_conn(inode);
1663 struct fuse_inode *fi = get_fuse_inode(inode);
1664 struct fuse_file *ff;
1665 int err;
1666
1667 ff = __fuse_write_file_get(fc, fi);
1668 err = fuse_flush_times(inode, ff);
1669 if (ff)
1670 fuse_file_put(ff, 0);
1671
1672 return err;
1673 }
1674
1675 static int fuse_writepage_locked(struct page *page)
1676 {
1677 struct address_space *mapping = page->mapping;
1678 struct inode *inode = mapping->host;
1679 struct fuse_conn *fc = get_fuse_conn(inode);
1680 struct fuse_inode *fi = get_fuse_inode(inode);
1681 struct fuse_req *req;
1682 struct page *tmp_page;
1683 int error = -ENOMEM;
1684
1685 set_page_writeback(page);
1686
1687 req = fuse_request_alloc_nofs(1);
1688 if (!req)
1689 goto err;
1690
1691 req->background = 1; /* writeback always goes to bg_queue */
1692 tmp_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
1693 if (!tmp_page)
1694 goto err_free;
1695
1696 error = -EIO;
1697 req->ff = fuse_write_file_get(fc, fi);
1698 if (!req->ff)
1699 goto err_free;
1700
1701 fuse_write_fill(req, req->ff, page_offset(page), 0);
1702
1703 copy_highpage(tmp_page, page);
1704 req->misc.write.in.write_flags |= FUSE_WRITE_CACHE;
1705 req->misc.write.next = NULL;
1706 req->in.argpages = 1;
1707 req->num_pages = 1;
1708 req->pages[0] = tmp_page;
1709 req->page_descs[0].offset = 0;
1710 req->page_descs[0].length = PAGE_SIZE;
1711 req->end = fuse_writepage_end;
1712 req->inode = inode;
1713
1714 inc_bdi_stat(mapping->backing_dev_info, BDI_WRITEBACK);
1715 inc_zone_page_state(tmp_page, NR_WRITEBACK_TEMP);
1716
1717 spin_lock(&fc->lock);
1718 list_add(&req->writepages_entry, &fi->writepages);
1719 list_add_tail(&req->list, &fi->queued_writes);
1720 fuse_flush_writepages(inode);
1721 spin_unlock(&fc->lock);
1722
1723 end_page_writeback(page);
1724
1725 return 0;
1726
1727 err_free:
1728 fuse_request_free(req);
1729 err:
1730 end_page_writeback(page);
1731 return error;
1732 }
1733
1734 static int fuse_writepage(struct page *page, struct writeback_control *wbc)
1735 {
1736 int err;
1737
1738 if (fuse_page_is_writeback(page->mapping->host, page->index)) {
1739 /*
1740 * ->writepages() should be called for sync() and friends. We
1741 * should only get here on direct reclaim and then we are
1742 * allowed to skip a page which is already in flight
1743 */
1744 WARN_ON(wbc->sync_mode == WB_SYNC_ALL);
1745
1746 redirty_page_for_writepage(wbc, page);
1747 return 0;
1748 }
1749
1750 err = fuse_writepage_locked(page);
1751 unlock_page(page);
1752
1753 return err;
1754 }
1755
1756 struct fuse_fill_wb_data {
1757 struct fuse_req *req;
1758 struct fuse_file *ff;
1759 struct inode *inode;
1760 struct page **orig_pages;
1761 };
1762
1763 static void fuse_writepages_send(struct fuse_fill_wb_data *data)
1764 {
1765 struct fuse_req *req = data->req;
1766 struct inode *inode = data->inode;
1767 struct fuse_conn *fc = get_fuse_conn(inode);
1768 struct fuse_inode *fi = get_fuse_inode(inode);
1769 int num_pages = req->num_pages;
1770 int i;
1771
1772 req->ff = fuse_file_get(data->ff);
1773 spin_lock(&fc->lock);
1774 list_add_tail(&req->list, &fi->queued_writes);
1775 fuse_flush_writepages(inode);
1776 spin_unlock(&fc->lock);
1777
1778 for (i = 0; i < num_pages; i++)
1779 end_page_writeback(data->orig_pages[i]);
1780 }
1781
1782 static bool fuse_writepage_in_flight(struct fuse_req *new_req,
1783 struct page *page)
1784 {
1785 struct fuse_conn *fc = get_fuse_conn(new_req->inode);
1786 struct fuse_inode *fi = get_fuse_inode(new_req->inode);
1787 struct fuse_req *tmp;
1788 struct fuse_req *old_req;
1789 bool found = false;
1790 pgoff_t curr_index;
1791
1792 BUG_ON(new_req->num_pages != 0);
1793
1794 spin_lock(&fc->lock);
1795 list_del(&new_req->writepages_entry);
1796 list_for_each_entry(old_req, &fi->writepages, writepages_entry) {
1797 BUG_ON(old_req->inode != new_req->inode);
1798 curr_index = old_req->misc.write.in.offset >> PAGE_CACHE_SHIFT;
1799 if (curr_index <= page->index &&
1800 page->index < curr_index + old_req->num_pages) {
1801 found = true;
1802 break;
1803 }
1804 }
1805 if (!found) {
1806 list_add(&new_req->writepages_entry, &fi->writepages);
1807 goto out_unlock;
1808 }
1809
1810 new_req->num_pages = 1;
1811 for (tmp = old_req; tmp != NULL; tmp = tmp->misc.write.next) {
1812 BUG_ON(tmp->inode != new_req->inode);
1813 curr_index = tmp->misc.write.in.offset >> PAGE_CACHE_SHIFT;
1814 if (tmp->num_pages == 1 &&
1815 curr_index == page->index) {
1816 old_req = tmp;
1817 }
1818 }
1819
1820 if (old_req->num_pages == 1 && (old_req->state == FUSE_REQ_INIT ||
1821 old_req->state == FUSE_REQ_PENDING)) {
1822 struct backing_dev_info *bdi = page->mapping->backing_dev_info;
1823
1824 copy_highpage(old_req->pages[0], page);
1825 spin_unlock(&fc->lock);
1826
1827 dec_bdi_stat(bdi, BDI_WRITEBACK);
1828 dec_zone_page_state(page, NR_WRITEBACK_TEMP);
1829 bdi_writeout_inc(bdi);
1830 fuse_writepage_free(fc, new_req);
1831 fuse_request_free(new_req);
1832 goto out;
1833 } else {
1834 new_req->misc.write.next = old_req->misc.write.next;
1835 old_req->misc.write.next = new_req;
1836 }
1837 out_unlock:
1838 spin_unlock(&fc->lock);
1839 out:
1840 return found;
1841 }
1842
1843 static int fuse_writepages_fill(struct page *page,
1844 struct writeback_control *wbc, void *_data)
1845 {
1846 struct fuse_fill_wb_data *data = _data;
1847 struct fuse_req *req = data->req;
1848 struct inode *inode = data->inode;
1849 struct fuse_conn *fc = get_fuse_conn(inode);
1850 struct page *tmp_page;
1851 bool is_writeback;
1852 int err;
1853
1854 if (!data->ff) {
1855 err = -EIO;
1856 data->ff = fuse_write_file_get(fc, get_fuse_inode(inode));
1857 if (!data->ff)
1858 goto out_unlock;
1859 }
1860
1861 /*
1862 * Being under writeback is unlikely but possible. For example direct
1863 * read to an mmaped fuse file will set the page dirty twice; once when
1864 * the pages are faulted with get_user_pages(), and then after the read
1865 * completed.
1866 */
1867 is_writeback = fuse_page_is_writeback(inode, page->index);
1868
1869 if (req && req->num_pages &&
1870 (is_writeback || req->num_pages == FUSE_MAX_PAGES_PER_REQ ||
1871 (req->num_pages + 1) * PAGE_CACHE_SIZE > fc->max_write ||
1872 data->orig_pages[req->num_pages - 1]->index + 1 != page->index)) {
1873 fuse_writepages_send(data);
1874 data->req = NULL;
1875 }
1876 err = -ENOMEM;
1877 tmp_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
1878 if (!tmp_page)
1879 goto out_unlock;
1880
1881 /*
1882 * The page must not be redirtied until the writeout is completed
1883 * (i.e. userspace has sent a reply to the write request). Otherwise
1884 * there could be more than one temporary page instance for each real
1885 * page.
1886 *
1887 * This is ensured by holding the page lock in page_mkwrite() while
1888 * checking fuse_page_is_writeback(). We already hold the page lock
1889 * since clear_page_dirty_for_io() and keep it held until we add the
1890 * request to the fi->writepages list and increment req->num_pages.
1891 * After this fuse_page_is_writeback() will indicate that the page is
1892 * under writeback, so we can release the page lock.
1893 */
1894 if (data->req == NULL) {
1895 struct fuse_inode *fi = get_fuse_inode(inode);
1896
1897 err = -ENOMEM;
1898 req = fuse_request_alloc_nofs(FUSE_MAX_PAGES_PER_REQ);
1899 if (!req) {
1900 __free_page(tmp_page);
1901 goto out_unlock;
1902 }
1903
1904 fuse_write_fill(req, data->ff, page_offset(page), 0);
1905 req->misc.write.in.write_flags |= FUSE_WRITE_CACHE;
1906 req->misc.write.next = NULL;
1907 req->in.argpages = 1;
1908 req->background = 1;
1909 req->num_pages = 0;
1910 req->end = fuse_writepage_end;
1911 req->inode = inode;
1912
1913 spin_lock(&fc->lock);
1914 list_add(&req->writepages_entry, &fi->writepages);
1915 spin_unlock(&fc->lock);
1916
1917 data->req = req;
1918 }
1919 set_page_writeback(page);
1920
1921 copy_highpage(tmp_page, page);
1922 req->pages[req->num_pages] = tmp_page;
1923 req->page_descs[req->num_pages].offset = 0;
1924 req->page_descs[req->num_pages].length = PAGE_SIZE;
1925
1926 inc_bdi_stat(page->mapping->backing_dev_info, BDI_WRITEBACK);
1927 inc_zone_page_state(tmp_page, NR_WRITEBACK_TEMP);
1928
1929 err = 0;
1930 if (is_writeback && fuse_writepage_in_flight(req, page)) {
1931 end_page_writeback(page);
1932 data->req = NULL;
1933 goto out_unlock;
1934 }
1935 data->orig_pages[req->num_pages] = page;
1936
1937 /*
1938 * Protected by fc->lock against concurrent access by
1939 * fuse_page_is_writeback().
1940 */
1941 spin_lock(&fc->lock);
1942 req->num_pages++;
1943 spin_unlock(&fc->lock);
1944
1945 out_unlock:
1946 unlock_page(page);
1947
1948 return err;
1949 }
1950
1951 static int fuse_writepages(struct address_space *mapping,
1952 struct writeback_control *wbc)
1953 {
1954 struct inode *inode = mapping->host;
1955 struct fuse_fill_wb_data data;
1956 int err;
1957
1958 err = -EIO;
1959 if (is_bad_inode(inode))
1960 goto out;
1961
1962 data.inode = inode;
1963 data.req = NULL;
1964 data.ff = NULL;
1965
1966 err = -ENOMEM;
1967 data.orig_pages = kzalloc(sizeof(struct page *) *
1968 FUSE_MAX_PAGES_PER_REQ,
1969 GFP_NOFS);
1970 if (!data.orig_pages)
1971 goto out;
1972
1973 err = write_cache_pages(mapping, wbc, fuse_writepages_fill, &data);
1974 if (data.req) {
1975 /* Ignore errors if we can write at least one page */
1976 BUG_ON(!data.req->num_pages);
1977 fuse_writepages_send(&data);
1978 err = 0;
1979 }
1980 if (data.ff)
1981 fuse_file_put(data.ff, false);
1982
1983 kfree(data.orig_pages);
1984 out:
1985 return err;
1986 }
1987
1988 /*
1989 * It's worthy to make sure that space is reserved on disk for the write,
1990 * but how to implement it without killing performance need more thinking.
1991 */
1992 static int fuse_write_begin(struct file *file, struct address_space *mapping,
1993 loff_t pos, unsigned len, unsigned flags,
1994 struct page **pagep, void **fsdata)
1995 {
1996 pgoff_t index = pos >> PAGE_CACHE_SHIFT;
1997 struct fuse_conn *fc = get_fuse_conn(file->f_dentry->d_inode);
1998 struct page *page;
1999 loff_t fsize;
2000 int err = -ENOMEM;
2001
2002 WARN_ON(!fc->writeback_cache);
2003
2004 page = grab_cache_page_write_begin(mapping, index, flags);
2005 if (!page)
2006 goto error;
2007
2008 fuse_wait_on_page_writeback(mapping->host, page->index);
2009
2010 if (PageUptodate(page) || len == PAGE_CACHE_SIZE)
2011 goto success;
2012 /*
2013 * Check if the start this page comes after the end of file, in which
2014 * case the readpage can be optimized away.
2015 */
2016 fsize = i_size_read(mapping->host);
2017 if (fsize <= (pos & PAGE_CACHE_MASK)) {
2018 size_t off = pos & ~PAGE_CACHE_MASK;
2019 if (off)
2020 zero_user_segment(page, 0, off);
2021 goto success;
2022 }
2023 err = fuse_do_readpage(file, page);
2024 if (err)
2025 goto cleanup;
2026 success:
2027 *pagep = page;
2028 return 0;
2029
2030 cleanup:
2031 unlock_page(page);
2032 page_cache_release(page);
2033 error:
2034 return err;
2035 }
2036
2037 static int fuse_write_end(struct file *file, struct address_space *mapping,
2038 loff_t pos, unsigned len, unsigned copied,
2039 struct page *page, void *fsdata)
2040 {
2041 struct inode *inode = page->mapping->host;
2042
2043 if (!PageUptodate(page)) {
2044 /* Zero any unwritten bytes at the end of the page */
2045 size_t endoff = (pos + copied) & ~PAGE_CACHE_MASK;
2046 if (endoff)
2047 zero_user_segment(page, endoff, PAGE_CACHE_SIZE);
2048 SetPageUptodate(page);
2049 }
2050
2051 fuse_write_update_size(inode, pos + copied);
2052 set_page_dirty(page);
2053 unlock_page(page);
2054 page_cache_release(page);
2055
2056 return copied;
2057 }
2058
2059 static int fuse_launder_page(struct page *page)
2060 {
2061 int err = 0;
2062 if (clear_page_dirty_for_io(page)) {
2063 struct inode *inode = page->mapping->host;
2064 err = fuse_writepage_locked(page);
2065 if (!err)
2066 fuse_wait_on_page_writeback(inode, page->index);
2067 }
2068 return err;
2069 }
2070
2071 /*
2072 * Write back dirty pages now, because there may not be any suitable
2073 * open files later
2074 */
2075 static void fuse_vma_close(struct vm_area_struct *vma)
2076 {
2077 filemap_write_and_wait(vma->vm_file->f_mapping);
2078 }
2079
2080 /*
2081 * Wait for writeback against this page to complete before allowing it
2082 * to be marked dirty again, and hence written back again, possibly
2083 * before the previous writepage completed.
2084 *
2085 * Block here, instead of in ->writepage(), so that the userspace fs
2086 * can only block processes actually operating on the filesystem.
2087 *
2088 * Otherwise unprivileged userspace fs would be able to block
2089 * unrelated:
2090 *
2091 * - page migration
2092 * - sync(2)
2093 * - try_to_free_pages() with order > PAGE_ALLOC_COSTLY_ORDER
2094 */
2095 static int fuse_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
2096 {
2097 struct page *page = vmf->page;
2098 struct inode *inode = file_inode(vma->vm_file);
2099
2100 file_update_time(vma->vm_file);
2101 lock_page(page);
2102 if (page->mapping != inode->i_mapping) {
2103 unlock_page(page);
2104 return VM_FAULT_NOPAGE;
2105 }
2106
2107 fuse_wait_on_page_writeback(inode, page->index);
2108 return VM_FAULT_LOCKED;
2109 }
2110
2111 static const struct vm_operations_struct fuse_file_vm_ops = {
2112 .close = fuse_vma_close,
2113 .fault = filemap_fault,
2114 .map_pages = filemap_map_pages,
2115 .page_mkwrite = fuse_page_mkwrite,
2116 .remap_pages = generic_file_remap_pages,
2117 };
2118
2119 static int fuse_file_mmap(struct file *file, struct vm_area_struct *vma)
2120 {
2121 if ((vma->vm_flags & VM_SHARED) && (vma->vm_flags & VM_MAYWRITE))
2122 fuse_link_write_file(file);
2123
2124 file_accessed(file);
2125 vma->vm_ops = &fuse_file_vm_ops;
2126 return 0;
2127 }
2128
2129 static int fuse_direct_mmap(struct file *file, struct vm_area_struct *vma)
2130 {
2131 /* Can't provide the coherency needed for MAP_SHARED */
2132 if (vma->vm_flags & VM_MAYSHARE)
2133 return -ENODEV;
2134
2135 invalidate_inode_pages2(file->f_mapping);
2136
2137 return generic_file_mmap(file, vma);
2138 }
2139
2140 static int convert_fuse_file_lock(const struct fuse_file_lock *ffl,
2141 struct file_lock *fl)
2142 {
2143 switch (ffl->type) {
2144 case F_UNLCK:
2145 break;
2146
2147 case F_RDLCK:
2148 case F_WRLCK:
2149 if (ffl->start > OFFSET_MAX || ffl->end > OFFSET_MAX ||
2150 ffl->end < ffl->start)
2151 return -EIO;
2152
2153 fl->fl_start = ffl->start;
2154 fl->fl_end = ffl->end;
2155 fl->fl_pid = ffl->pid;
2156 break;
2157
2158 default:
2159 return -EIO;
2160 }
2161 fl->fl_type = ffl->type;
2162 return 0;
2163 }
2164
2165 static void fuse_lk_fill(struct fuse_req *req, struct file *file,
2166 const struct file_lock *fl, int opcode, pid_t pid,
2167 int flock)
2168 {
2169 struct inode *inode = file_inode(file);
2170 struct fuse_conn *fc = get_fuse_conn(inode);
2171 struct fuse_file *ff = file->private_data;
2172 struct fuse_lk_in *arg = &req->misc.lk_in;
2173
2174 arg->fh = ff->fh;
2175 arg->owner = fuse_lock_owner_id(fc, fl->fl_owner);
2176 arg->lk.start = fl->fl_start;
2177 arg->lk.end = fl->fl_end;
2178 arg->lk.type = fl->fl_type;
2179 arg->lk.pid = pid;
2180 if (flock)
2181 arg->lk_flags |= FUSE_LK_FLOCK;
2182 req->in.h.opcode = opcode;
2183 req->in.h.nodeid = get_node_id(inode);
2184 req->in.numargs = 1;
2185 req->in.args[0].size = sizeof(*arg);
2186 req->in.args[0].value = arg;
2187 }
2188
2189 static int fuse_getlk(struct file *file, struct file_lock *fl)
2190 {
2191 struct inode *inode = file_inode(file);
2192 struct fuse_conn *fc = get_fuse_conn(inode);
2193 struct fuse_req *req;
2194 struct fuse_lk_out outarg;
2195 int err;
2196
2197 req = fuse_get_req_nopages(fc);
2198 if (IS_ERR(req))
2199 return PTR_ERR(req);
2200
2201 fuse_lk_fill(req, file, fl, FUSE_GETLK, 0, 0);
2202 req->out.numargs = 1;
2203 req->out.args[0].size = sizeof(outarg);
2204 req->out.args[0].value = &outarg;
2205 fuse_request_send(fc, req);
2206 err = req->out.h.error;
2207 fuse_put_request(fc, req);
2208 if (!err)
2209 err = convert_fuse_file_lock(&outarg.lk, fl);
2210
2211 return err;
2212 }
2213
2214 static int fuse_setlk(struct file *file, struct file_lock *fl, int flock)
2215 {
2216 struct inode *inode = file_inode(file);
2217 struct fuse_conn *fc = get_fuse_conn(inode);
2218 struct fuse_req *req;
2219 int opcode = (fl->fl_flags & FL_SLEEP) ? FUSE_SETLKW : FUSE_SETLK;
2220 pid_t pid = fl->fl_type != F_UNLCK ? current->tgid : 0;
2221 int err;
2222
2223 if (fl->fl_lmops && fl->fl_lmops->lm_grant) {
2224 /* NLM needs asynchronous locks, which we don't support yet */
2225 return -ENOLCK;
2226 }
2227
2228 /* Unlock on close is handled by the flush method */
2229 if (fl->fl_flags & FL_CLOSE)
2230 return 0;
2231
2232 req = fuse_get_req_nopages(fc);
2233 if (IS_ERR(req))
2234 return PTR_ERR(req);
2235
2236 fuse_lk_fill(req, file, fl, opcode, pid, flock);
2237 fuse_request_send(fc, req);
2238 err = req->out.h.error;
2239 /* locking is restartable */
2240 if (err == -EINTR)
2241 err = -ERESTARTSYS;
2242 fuse_put_request(fc, req);
2243 return err;
2244 }
2245
2246 static int fuse_file_lock(struct file *file, int cmd, struct file_lock *fl)
2247 {
2248 struct inode *inode = file_inode(file);
2249 struct fuse_conn *fc = get_fuse_conn(inode);
2250 int err;
2251
2252 if (cmd == F_CANCELLK) {
2253 err = 0;
2254 } else if (cmd == F_GETLK) {
2255 if (fc->no_lock) {
2256 posix_test_lock(file, fl);
2257 err = 0;
2258 } else
2259 err = fuse_getlk(file, fl);
2260 } else {
2261 if (fc->no_lock)
2262 err = posix_lock_file(file, fl, NULL);
2263 else
2264 err = fuse_setlk(file, fl, 0);
2265 }
2266 return err;
2267 }
2268
2269 static int fuse_file_flock(struct file *file, int cmd, struct file_lock *fl)
2270 {
2271 struct inode *inode = file_inode(file);
2272 struct fuse_conn *fc = get_fuse_conn(inode);
2273 int err;
2274
2275 if (fc->no_flock) {
2276 err = flock_lock_file_wait(file, fl);
2277 } else {
2278 struct fuse_file *ff = file->private_data;
2279
2280 /* emulate flock with POSIX locks */
2281 fl->fl_owner = (fl_owner_t) file;
2282 ff->flock = true;
2283 err = fuse_setlk(file, fl, 1);
2284 }
2285
2286 return err;
2287 }
2288
2289 static sector_t fuse_bmap(struct address_space *mapping, sector_t block)
2290 {
2291 struct inode *inode = mapping->host;
2292 struct fuse_conn *fc = get_fuse_conn(inode);
2293 struct fuse_req *req;
2294 struct fuse_bmap_in inarg;
2295 struct fuse_bmap_out outarg;
2296 int err;
2297
2298 if (!inode->i_sb->s_bdev || fc->no_bmap)
2299 return 0;
2300
2301 req = fuse_get_req_nopages(fc);
2302 if (IS_ERR(req))
2303 return 0;
2304
2305 memset(&inarg, 0, sizeof(inarg));
2306 inarg.block = block;
2307 inarg.blocksize = inode->i_sb->s_blocksize;
2308 req->in.h.opcode = FUSE_BMAP;
2309 req->in.h.nodeid = get_node_id(inode);
2310 req->in.numargs = 1;
2311 req->in.args[0].size = sizeof(inarg);
2312 req->in.args[0].value = &inarg;
2313 req->out.numargs = 1;
2314 req->out.args[0].size = sizeof(outarg);
2315 req->out.args[0].value = &outarg;
2316 fuse_request_send(fc, req);
2317 err = req->out.h.error;
2318 fuse_put_request(fc, req);
2319 if (err == -ENOSYS)
2320 fc->no_bmap = 1;
2321
2322 return err ? 0 : outarg.block;
2323 }
2324
2325 static loff_t fuse_file_llseek(struct file *file, loff_t offset, int whence)
2326 {
2327 loff_t retval;
2328 struct inode *inode = file_inode(file);
2329
2330 /* No i_mutex protection necessary for SEEK_CUR and SEEK_SET */
2331 if (whence == SEEK_CUR || whence == SEEK_SET)
2332 return generic_file_llseek(file, offset, whence);
2333
2334 mutex_lock(&inode->i_mutex);
2335 retval = fuse_update_attributes(inode, NULL, file, NULL);
2336 if (!retval)
2337 retval = generic_file_llseek(file, offset, whence);
2338 mutex_unlock(&inode->i_mutex);
2339
2340 return retval;
2341 }
2342
2343 static int fuse_ioctl_copy_user(struct page **pages, struct iovec *iov,
2344 unsigned int nr_segs, size_t bytes, bool to_user)
2345 {
2346 struct iov_iter ii;
2347 int page_idx = 0;
2348
2349 if (!bytes)
2350 return 0;
2351
2352 iov_iter_init(&ii, to_user ? READ : WRITE, iov, nr_segs, bytes);
2353
2354 while (iov_iter_count(&ii)) {
2355 struct page *page = pages[page_idx++];
2356 size_t todo = min_t(size_t, PAGE_SIZE, iov_iter_count(&ii));
2357 void *kaddr;
2358
2359 kaddr = kmap(page);
2360
2361 while (todo) {
2362 char __user *uaddr = ii.iov->iov_base + ii.iov_offset;
2363 size_t iov_len = ii.iov->iov_len - ii.iov_offset;
2364 size_t copy = min(todo, iov_len);
2365 size_t left;
2366
2367 if (!to_user)
2368 left = copy_from_user(kaddr, uaddr, copy);
2369 else
2370 left = copy_to_user(uaddr, kaddr, copy);
2371
2372 if (unlikely(left))
2373 return -EFAULT;
2374
2375 iov_iter_advance(&ii, copy);
2376 todo -= copy;
2377 kaddr += copy;
2378 }
2379
2380 kunmap(page);
2381 }
2382
2383 return 0;
2384 }
2385
2386 /*
2387 * CUSE servers compiled on 32bit broke on 64bit kernels because the
2388 * ABI was defined to be 'struct iovec' which is different on 32bit
2389 * and 64bit. Fortunately we can determine which structure the server
2390 * used from the size of the reply.
2391 */
2392 static int fuse_copy_ioctl_iovec_old(struct iovec *dst, void *src,
2393 size_t transferred, unsigned count,
2394 bool is_compat)
2395 {
2396 #ifdef CONFIG_COMPAT
2397 if (count * sizeof(struct compat_iovec) == transferred) {
2398 struct compat_iovec *ciov = src;
2399 unsigned i;
2400
2401 /*
2402 * With this interface a 32bit server cannot support
2403 * non-compat (i.e. ones coming from 64bit apps) ioctl
2404 * requests
2405 */
2406 if (!is_compat)
2407 return -EINVAL;
2408
2409 for (i = 0; i < count; i++) {
2410 dst[i].iov_base = compat_ptr(ciov[i].iov_base);
2411 dst[i].iov_len = ciov[i].iov_len;
2412 }
2413 return 0;
2414 }
2415 #endif
2416
2417 if (count * sizeof(struct iovec) != transferred)
2418 return -EIO;
2419
2420 memcpy(dst, src, transferred);
2421 return 0;
2422 }
2423
2424 /* Make sure iov_length() won't overflow */
2425 static int fuse_verify_ioctl_iov(struct iovec *iov, size_t count)
2426 {
2427 size_t n;
2428 u32 max = FUSE_MAX_PAGES_PER_REQ << PAGE_SHIFT;
2429
2430 for (n = 0; n < count; n++, iov++) {
2431 if (iov->iov_len > (size_t) max)
2432 return -ENOMEM;
2433 max -= iov->iov_len;
2434 }
2435 return 0;
2436 }
2437
2438 static int fuse_copy_ioctl_iovec(struct fuse_conn *fc, struct iovec *dst,
2439 void *src, size_t transferred, unsigned count,
2440 bool is_compat)
2441 {
2442 unsigned i;
2443 struct fuse_ioctl_iovec *fiov = src;
2444
2445 if (fc->minor < 16) {
2446 return fuse_copy_ioctl_iovec_old(dst, src, transferred,
2447 count, is_compat);
2448 }
2449
2450 if (count * sizeof(struct fuse_ioctl_iovec) != transferred)
2451 return -EIO;
2452
2453 for (i = 0; i < count; i++) {
2454 /* Did the server supply an inappropriate value? */
2455 if (fiov[i].base != (unsigned long) fiov[i].base ||
2456 fiov[i].len != (unsigned long) fiov[i].len)
2457 return -EIO;
2458
2459 dst[i].iov_base = (void __user *) (unsigned long) fiov[i].base;
2460 dst[i].iov_len = (size_t) fiov[i].len;
2461
2462 #ifdef CONFIG_COMPAT
2463 if (is_compat &&
2464 (ptr_to_compat(dst[i].iov_base) != fiov[i].base ||
2465 (compat_size_t) dst[i].iov_len != fiov[i].len))
2466 return -EIO;
2467 #endif
2468 }
2469
2470 return 0;
2471 }
2472
2473
2474 /*
2475 * For ioctls, there is no generic way to determine how much memory
2476 * needs to be read and/or written. Furthermore, ioctls are allowed
2477 * to dereference the passed pointer, so the parameter requires deep
2478 * copying but FUSE has no idea whatsoever about what to copy in or
2479 * out.
2480 *
2481 * This is solved by allowing FUSE server to retry ioctl with
2482 * necessary in/out iovecs. Let's assume the ioctl implementation
2483 * needs to read in the following structure.
2484 *
2485 * struct a {
2486 * char *buf;
2487 * size_t buflen;
2488 * }
2489 *
2490 * On the first callout to FUSE server, inarg->in_size and
2491 * inarg->out_size will be NULL; then, the server completes the ioctl
2492 * with FUSE_IOCTL_RETRY set in out->flags, out->in_iovs set to 1 and
2493 * the actual iov array to
2494 *
2495 * { { .iov_base = inarg.arg, .iov_len = sizeof(struct a) } }
2496 *
2497 * which tells FUSE to copy in the requested area and retry the ioctl.
2498 * On the second round, the server has access to the structure and
2499 * from that it can tell what to look for next, so on the invocation,
2500 * it sets FUSE_IOCTL_RETRY, out->in_iovs to 2 and iov array to
2501 *
2502 * { { .iov_base = inarg.arg, .iov_len = sizeof(struct a) },
2503 * { .iov_base = a.buf, .iov_len = a.buflen } }
2504 *
2505 * FUSE will copy both struct a and the pointed buffer from the
2506 * process doing the ioctl and retry ioctl with both struct a and the
2507 * buffer.
2508 *
2509 * This time, FUSE server has everything it needs and completes ioctl
2510 * without FUSE_IOCTL_RETRY which finishes the ioctl call.
2511 *
2512 * Copying data out works the same way.
2513 *
2514 * Note that if FUSE_IOCTL_UNRESTRICTED is clear, the kernel
2515 * automatically initializes in and out iovs by decoding @cmd with
2516 * _IOC_* macros and the server is not allowed to request RETRY. This
2517 * limits ioctl data transfers to well-formed ioctls and is the forced
2518 * behavior for all FUSE servers.
2519 */
2520 long fuse_do_ioctl(struct file *file, unsigned int cmd, unsigned long arg,
2521 unsigned int flags)
2522 {
2523 struct fuse_file *ff = file->private_data;
2524 struct fuse_conn *fc = ff->fc;
2525 struct fuse_ioctl_in inarg = {
2526 .fh = ff->fh,
2527 .cmd = cmd,
2528 .arg = arg,
2529 .flags = flags
2530 };
2531 struct fuse_ioctl_out outarg;
2532 struct fuse_req *req = NULL;
2533 struct page **pages = NULL;
2534 struct iovec *iov_page = NULL;
2535 struct iovec *in_iov = NULL, *out_iov = NULL;
2536 unsigned int in_iovs = 0, out_iovs = 0, num_pages = 0, max_pages;
2537 size_t in_size, out_size, transferred;
2538 int err;
2539
2540 #if BITS_PER_LONG == 32
2541 inarg.flags |= FUSE_IOCTL_32BIT;
2542 #else
2543 if (flags & FUSE_IOCTL_COMPAT)
2544 inarg.flags |= FUSE_IOCTL_32BIT;
2545 #endif
2546
2547 /* assume all the iovs returned by client always fits in a page */
2548 BUILD_BUG_ON(sizeof(struct fuse_ioctl_iovec) * FUSE_IOCTL_MAX_IOV > PAGE_SIZE);
2549
2550 err = -ENOMEM;
2551 pages = kcalloc(FUSE_MAX_PAGES_PER_REQ, sizeof(pages[0]), GFP_KERNEL);
2552 iov_page = (struct iovec *) __get_free_page(GFP_KERNEL);
2553 if (!pages || !iov_page)
2554 goto out;
2555
2556 /*
2557 * If restricted, initialize IO parameters as encoded in @cmd.
2558 * RETRY from server is not allowed.
2559 */
2560 if (!(flags & FUSE_IOCTL_UNRESTRICTED)) {
2561 struct iovec *iov = iov_page;
2562
2563 iov->iov_base = (void __user *)arg;
2564 iov->iov_len = _IOC_SIZE(cmd);
2565
2566 if (_IOC_DIR(cmd) & _IOC_WRITE) {
2567 in_iov = iov;
2568 in_iovs = 1;
2569 }
2570
2571 if (_IOC_DIR(cmd) & _IOC_READ) {
2572 out_iov = iov;
2573 out_iovs = 1;
2574 }
2575 }
2576
2577 retry:
2578 inarg.in_size = in_size = iov_length(in_iov, in_iovs);
2579 inarg.out_size = out_size = iov_length(out_iov, out_iovs);
2580
2581 /*
2582 * Out data can be used either for actual out data or iovs,
2583 * make sure there always is at least one page.
2584 */
2585 out_size = max_t(size_t, out_size, PAGE_SIZE);
2586 max_pages = DIV_ROUND_UP(max(in_size, out_size), PAGE_SIZE);
2587
2588 /* make sure there are enough buffer pages and init request with them */
2589 err = -ENOMEM;
2590 if (max_pages > FUSE_MAX_PAGES_PER_REQ)
2591 goto out;
2592 while (num_pages < max_pages) {
2593 pages[num_pages] = alloc_page(GFP_KERNEL | __GFP_HIGHMEM);
2594 if (!pages[num_pages])
2595 goto out;
2596 num_pages++;
2597 }
2598
2599 req = fuse_get_req(fc, num_pages);
2600 if (IS_ERR(req)) {
2601 err = PTR_ERR(req);
2602 req = NULL;
2603 goto out;
2604 }
2605 memcpy(req->pages, pages, sizeof(req->pages[0]) * num_pages);
2606 req->num_pages = num_pages;
2607 fuse_page_descs_length_init(req, 0, req->num_pages);
2608
2609 /* okay, let's send it to the client */
2610 req->in.h.opcode = FUSE_IOCTL;
2611 req->in.h.nodeid = ff->nodeid;
2612 req->in.numargs = 1;
2613 req->in.args[0].size = sizeof(inarg);
2614 req->in.args[0].value = &inarg;
2615 if (in_size) {
2616 req->in.numargs++;
2617 req->in.args[1].size = in_size;
2618 req->in.argpages = 1;
2619
2620 err = fuse_ioctl_copy_user(pages, in_iov, in_iovs, in_size,
2621 false);
2622 if (err)
2623 goto out;
2624 }
2625
2626 req->out.numargs = 2;
2627 req->out.args[0].size = sizeof(outarg);
2628 req->out.args[0].value = &outarg;
2629 req->out.args[1].size = out_size;
2630 req->out.argpages = 1;
2631 req->out.argvar = 1;
2632
2633 fuse_request_send(fc, req);
2634 err = req->out.h.error;
2635 transferred = req->out.args[1].size;
2636 fuse_put_request(fc, req);
2637 req = NULL;
2638 if (err)
2639 goto out;
2640
2641 /* did it ask for retry? */
2642 if (outarg.flags & FUSE_IOCTL_RETRY) {
2643 void *vaddr;
2644
2645 /* no retry if in restricted mode */
2646 err = -EIO;
2647 if (!(flags & FUSE_IOCTL_UNRESTRICTED))
2648 goto out;
2649
2650 in_iovs = outarg.in_iovs;
2651 out_iovs = outarg.out_iovs;
2652
2653 /*
2654 * Make sure things are in boundary, separate checks
2655 * are to protect against overflow.
2656 */
2657 err = -ENOMEM;
2658 if (in_iovs > FUSE_IOCTL_MAX_IOV ||
2659 out_iovs > FUSE_IOCTL_MAX_IOV ||
2660 in_iovs + out_iovs > FUSE_IOCTL_MAX_IOV)
2661 goto out;
2662
2663 vaddr = kmap_atomic(pages[0]);
2664 err = fuse_copy_ioctl_iovec(fc, iov_page, vaddr,
2665 transferred, in_iovs + out_iovs,
2666 (flags & FUSE_IOCTL_COMPAT) != 0);
2667 kunmap_atomic(vaddr);
2668 if (err)
2669 goto out;
2670
2671 in_iov = iov_page;
2672 out_iov = in_iov + in_iovs;
2673
2674 err = fuse_verify_ioctl_iov(in_iov, in_iovs);
2675 if (err)
2676 goto out;
2677
2678 err = fuse_verify_ioctl_iov(out_iov, out_iovs);
2679 if (err)
2680 goto out;
2681
2682 goto retry;
2683 }
2684
2685 err = -EIO;
2686 if (transferred > inarg.out_size)
2687 goto out;
2688
2689 err = fuse_ioctl_copy_user(pages, out_iov, out_iovs, transferred, true);
2690 out:
2691 if (req)
2692 fuse_put_request(fc, req);
2693 free_page((unsigned long) iov_page);
2694 while (num_pages)
2695 __free_page(pages[--num_pages]);
2696 kfree(pages);
2697
2698 return err ? err : outarg.result;
2699 }
2700 EXPORT_SYMBOL_GPL(fuse_do_ioctl);
2701
2702 long fuse_ioctl_common(struct file *file, unsigned int cmd,
2703 unsigned long arg, unsigned int flags)
2704 {
2705 struct inode *inode = file_inode(file);
2706 struct fuse_conn *fc = get_fuse_conn(inode);
2707
2708 if (!fuse_allow_current_process(fc))
2709 return -EACCES;
2710
2711 if (is_bad_inode(inode))
2712 return -EIO;
2713
2714 return fuse_do_ioctl(file, cmd, arg, flags);
2715 }
2716
2717 static long fuse_file_ioctl(struct file *file, unsigned int cmd,
2718 unsigned long arg)
2719 {
2720 return fuse_ioctl_common(file, cmd, arg, 0);
2721 }
2722
2723 static long fuse_file_compat_ioctl(struct file *file, unsigned int cmd,
2724 unsigned long arg)
2725 {
2726 return fuse_ioctl_common(file, cmd, arg, FUSE_IOCTL_COMPAT);
2727 }
2728
2729 /*
2730 * All files which have been polled are linked to RB tree
2731 * fuse_conn->polled_files which is indexed by kh. Walk the tree and
2732 * find the matching one.
2733 */
2734 static struct rb_node **fuse_find_polled_node(struct fuse_conn *fc, u64 kh,
2735 struct rb_node **parent_out)
2736 {
2737 struct rb_node **link = &fc->polled_files.rb_node;
2738 struct rb_node *last = NULL;
2739
2740 while (*link) {
2741 struct fuse_file *ff;
2742
2743 last = *link;
2744 ff = rb_entry(last, struct fuse_file, polled_node);
2745
2746 if (kh < ff->kh)
2747 link = &last->rb_left;
2748 else if (kh > ff->kh)
2749 link = &last->rb_right;
2750 else
2751 return link;
2752 }
2753
2754 if (parent_out)
2755 *parent_out = last;
2756 return link;
2757 }
2758
2759 /*
2760 * The file is about to be polled. Make sure it's on the polled_files
2761 * RB tree. Note that files once added to the polled_files tree are
2762 * not removed before the file is released. This is because a file
2763 * polled once is likely to be polled again.
2764 */
2765 static void fuse_register_polled_file(struct fuse_conn *fc,
2766 struct fuse_file *ff)
2767 {
2768 spin_lock(&fc->lock);
2769 if (RB_EMPTY_NODE(&ff->polled_node)) {
2770 struct rb_node **link, *uninitialized_var(parent);
2771
2772 link = fuse_find_polled_node(fc, ff->kh, &parent);
2773 BUG_ON(*link);
2774 rb_link_node(&ff->polled_node, parent, link);
2775 rb_insert_color(&ff->polled_node, &fc->polled_files);
2776 }
2777 spin_unlock(&fc->lock);
2778 }
2779
2780 unsigned fuse_file_poll(struct file *file, poll_table *wait)
2781 {
2782 struct fuse_file *ff = file->private_data;
2783 struct fuse_conn *fc = ff->fc;
2784 struct fuse_poll_in inarg = { .fh = ff->fh, .kh = ff->kh };
2785 struct fuse_poll_out outarg;
2786 struct fuse_req *req;
2787 int err;
2788
2789 if (fc->no_poll)
2790 return DEFAULT_POLLMASK;
2791
2792 poll_wait(file, &ff->poll_wait, wait);
2793 inarg.events = (__u32)poll_requested_events(wait);
2794
2795 /*
2796 * Ask for notification iff there's someone waiting for it.
2797 * The client may ignore the flag and always notify.
2798 */
2799 if (waitqueue_active(&ff->poll_wait)) {
2800 inarg.flags |= FUSE_POLL_SCHEDULE_NOTIFY;
2801 fuse_register_polled_file(fc, ff);
2802 }
2803
2804 req = fuse_get_req_nopages(fc);
2805 if (IS_ERR(req))
2806 return POLLERR;
2807
2808 req->in.h.opcode = FUSE_POLL;
2809 req->in.h.nodeid = ff->nodeid;
2810 req->in.numargs = 1;
2811 req->in.args[0].size = sizeof(inarg);
2812 req->in.args[0].value = &inarg;
2813 req->out.numargs = 1;
2814 req->out.args[0].size = sizeof(outarg);
2815 req->out.args[0].value = &outarg;
2816 fuse_request_send(fc, req);
2817 err = req->out.h.error;
2818 fuse_put_request(fc, req);
2819
2820 if (!err)
2821 return outarg.revents;
2822 if (err == -ENOSYS) {
2823 fc->no_poll = 1;
2824 return DEFAULT_POLLMASK;
2825 }
2826 return POLLERR;
2827 }
2828 EXPORT_SYMBOL_GPL(fuse_file_poll);
2829
2830 /*
2831 * This is called from fuse_handle_notify() on FUSE_NOTIFY_POLL and
2832 * wakes up the poll waiters.
2833 */
2834 int fuse_notify_poll_wakeup(struct fuse_conn *fc,
2835 struct fuse_notify_poll_wakeup_out *outarg)
2836 {
2837 u64 kh = outarg->kh;
2838 struct rb_node **link;
2839
2840 spin_lock(&fc->lock);
2841
2842 link = fuse_find_polled_node(fc, kh, NULL);
2843 if (*link) {
2844 struct fuse_file *ff;
2845
2846 ff = rb_entry(*link, struct fuse_file, polled_node);
2847 wake_up_interruptible_sync(&ff->poll_wait);
2848 }
2849
2850 spin_unlock(&fc->lock);
2851 return 0;
2852 }
2853
2854 static void fuse_do_truncate(struct file *file)
2855 {
2856 struct inode *inode = file->f_mapping->host;
2857 struct iattr attr;
2858
2859 attr.ia_valid = ATTR_SIZE;
2860 attr.ia_size = i_size_read(inode);
2861
2862 attr.ia_file = file;
2863 attr.ia_valid |= ATTR_FILE;
2864
2865 fuse_do_setattr(inode, &attr, file);
2866 }
2867
2868 static inline loff_t fuse_round_up(loff_t off)
2869 {
2870 return round_up(off, FUSE_MAX_PAGES_PER_REQ << PAGE_SHIFT);
2871 }
2872
2873 static ssize_t
2874 fuse_direct_IO(int rw, struct kiocb *iocb, struct iov_iter *iter,
2875 loff_t offset)
2876 {
2877 ssize_t ret = 0;
2878 struct file *file = iocb->ki_filp;
2879 struct fuse_file *ff = file->private_data;
2880 bool async_dio = ff->fc->async_dio;
2881 loff_t pos = 0;
2882 struct inode *inode;
2883 loff_t i_size;
2884 size_t count = iov_iter_count(iter);
2885 struct fuse_io_priv *io;
2886
2887 pos = offset;
2888 inode = file->f_mapping->host;
2889 i_size = i_size_read(inode);
2890
2891 if ((rw == READ) && (offset > i_size))
2892 return 0;
2893
2894 /* optimization for short read */
2895 if (async_dio && rw != WRITE && offset + count > i_size) {
2896 if (offset >= i_size)
2897 return 0;
2898 count = min_t(loff_t, count, fuse_round_up(i_size - offset));
2899 if (iter->count > count)
2900 iter->count = count;
2901 }
2902
2903 io = kmalloc(sizeof(struct fuse_io_priv), GFP_KERNEL);
2904 if (!io)
2905 return -ENOMEM;
2906 spin_lock_init(&io->lock);
2907 io->reqs = 1;
2908 io->bytes = -1;
2909 io->size = 0;
2910 io->offset = offset;
2911 io->write = (rw == WRITE);
2912 io->err = 0;
2913 io->file = file;
2914 /*
2915 * By default, we want to optimize all I/Os with async request
2916 * submission to the client filesystem if supported.
2917 */
2918 io->async = async_dio;
2919 io->iocb = iocb;
2920
2921 /*
2922 * We cannot asynchronously extend the size of a file. We have no method
2923 * to wait on real async I/O requests, so we must submit this request
2924 * synchronously.
2925 */
2926 if (!is_sync_kiocb(iocb) && (offset + count > i_size) && rw == WRITE)
2927 io->async = false;
2928
2929 if (rw == WRITE)
2930 ret = __fuse_direct_write(io, iter, &pos);
2931 else
2932 ret = __fuse_direct_read(io, iter, &pos);
2933
2934 if (io->async) {
2935 fuse_aio_complete(io, ret < 0 ? ret : 0, -1);
2936
2937 /* we have a non-extending, async request, so return */
2938 if (!is_sync_kiocb(iocb))
2939 return -EIOCBQUEUED;
2940
2941 ret = wait_on_sync_kiocb(iocb);
2942 } else {
2943 kfree(io);
2944 }
2945
2946 if (rw == WRITE) {
2947 if (ret > 0)
2948 fuse_write_update_size(inode, pos);
2949 else if (ret < 0 && offset + count > i_size)
2950 fuse_do_truncate(file);
2951 }
2952
2953 return ret;
2954 }
2955
2956 static long fuse_file_fallocate(struct file *file, int mode, loff_t offset,
2957 loff_t length)
2958 {
2959 struct fuse_file *ff = file->private_data;
2960 struct inode *inode = file->f_inode;
2961 struct fuse_inode *fi = get_fuse_inode(inode);
2962 struct fuse_conn *fc = ff->fc;
2963 struct fuse_req *req;
2964 struct fuse_fallocate_in inarg = {
2965 .fh = ff->fh,
2966 .offset = offset,
2967 .length = length,
2968 .mode = mode
2969 };
2970 int err;
2971 bool lock_inode = !(mode & FALLOC_FL_KEEP_SIZE) ||
2972 (mode & FALLOC_FL_PUNCH_HOLE);
2973
2974 if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE))
2975 return -EOPNOTSUPP;
2976
2977 if (fc->no_fallocate)
2978 return -EOPNOTSUPP;
2979
2980 if (lock_inode) {
2981 mutex_lock(&inode->i_mutex);
2982 if (mode & FALLOC_FL_PUNCH_HOLE) {
2983 loff_t endbyte = offset + length - 1;
2984 err = filemap_write_and_wait_range(inode->i_mapping,
2985 offset, endbyte);
2986 if (err)
2987 goto out;
2988
2989 fuse_sync_writes(inode);
2990 }
2991 }
2992
2993 if (!(mode & FALLOC_FL_KEEP_SIZE))
2994 set_bit(FUSE_I_SIZE_UNSTABLE, &fi->state);
2995
2996 req = fuse_get_req_nopages(fc);
2997 if (IS_ERR(req)) {
2998 err = PTR_ERR(req);
2999 goto out;
3000 }
3001
3002 req->in.h.opcode = FUSE_FALLOCATE;
3003 req->in.h.nodeid = ff->nodeid;
3004 req->in.numargs = 1;
3005 req->in.args[0].size = sizeof(inarg);
3006 req->in.args[0].value = &inarg;
3007 fuse_request_send(fc, req);
3008 err = req->out.h.error;
3009 if (err == -ENOSYS) {
3010 fc->no_fallocate = 1;
3011 err = -EOPNOTSUPP;
3012 }
3013 fuse_put_request(fc, req);
3014
3015 if (err)
3016 goto out;
3017
3018 /* we could have extended the file */
3019 if (!(mode & FALLOC_FL_KEEP_SIZE)) {
3020 bool changed = fuse_write_update_size(inode, offset + length);
3021
3022 if (changed && fc->writeback_cache)
3023 file_update_time(file);
3024 }
3025
3026 if (mode & FALLOC_FL_PUNCH_HOLE)
3027 truncate_pagecache_range(inode, offset, offset + length - 1);
3028
3029 fuse_invalidate_attr(inode);
3030
3031 out:
3032 if (!(mode & FALLOC_FL_KEEP_SIZE))
3033 clear_bit(FUSE_I_SIZE_UNSTABLE, &fi->state);
3034
3035 if (lock_inode)
3036 mutex_unlock(&inode->i_mutex);
3037
3038 return err;
3039 }
3040
3041 static const struct file_operations fuse_file_operations = {
3042 .llseek = fuse_file_llseek,
3043 .read = do_sync_read,
3044 .aio_read = fuse_file_aio_read,
3045 .write = do_sync_write,
3046 .aio_write = fuse_file_aio_write,
3047 .mmap = fuse_file_mmap,
3048 .open = fuse_open,
3049 .flush = fuse_flush,
3050 .release = fuse_release,
3051 .fsync = fuse_fsync,
3052 .lock = fuse_file_lock,
3053 .flock = fuse_file_flock,
3054 .splice_read = generic_file_splice_read,
3055 .unlocked_ioctl = fuse_file_ioctl,
3056 .compat_ioctl = fuse_file_compat_ioctl,
3057 .poll = fuse_file_poll,
3058 .fallocate = fuse_file_fallocate,
3059 };
3060
3061 static const struct file_operations fuse_direct_io_file_operations = {
3062 .llseek = fuse_file_llseek,
3063 .read = fuse_direct_read,
3064 .write = fuse_direct_write,
3065 .mmap = fuse_direct_mmap,
3066 .open = fuse_open,
3067 .flush = fuse_flush,
3068 .release = fuse_release,
3069 .fsync = fuse_fsync,
3070 .lock = fuse_file_lock,
3071 .flock = fuse_file_flock,
3072 .unlocked_ioctl = fuse_file_ioctl,
3073 .compat_ioctl = fuse_file_compat_ioctl,
3074 .poll = fuse_file_poll,
3075 .fallocate = fuse_file_fallocate,
3076 /* no splice_read */
3077 };
3078
3079 static const struct address_space_operations fuse_file_aops = {
3080 .readpage = fuse_readpage,
3081 .writepage = fuse_writepage,
3082 .writepages = fuse_writepages,
3083 .launder_page = fuse_launder_page,
3084 .readpages = fuse_readpages,
3085 .set_page_dirty = __set_page_dirty_nobuffers,
3086 .bmap = fuse_bmap,
3087 .direct_IO = fuse_direct_IO,
3088 .write_begin = fuse_write_begin,
3089 .write_end = fuse_write_end,
3090 };
3091
3092 void fuse_init_file_inode(struct inode *inode)
3093 {
3094 inode->i_fop = &fuse_file_operations;
3095 inode->i_data.a_ops = &fuse_file_aops;
3096 }
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