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Merge tag 'fuse-update-5.15' of git://git.kernel.org/pub/scm/linux/kernel/git/mszered...
[mirror_ubuntu-jammy-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/sched/signal.h>
16 #include <linux/module.h>
17 #include <linux/swap.h>
18 #include <linux/falloc.h>
19 #include <linux/uio.h>
20 #include <linux/fs.h>
21
22 static int fuse_send_open(struct fuse_mount *fm, u64 nodeid,
23 unsigned int open_flags, int opcode,
24 struct fuse_open_out *outargp)
25 {
26 struct fuse_open_in inarg;
27 FUSE_ARGS(args);
28
29 memset(&inarg, 0, sizeof(inarg));
30 inarg.flags = open_flags & ~(O_CREAT | O_EXCL | O_NOCTTY);
31 if (!fm->fc->atomic_o_trunc)
32 inarg.flags &= ~O_TRUNC;
33
34 if (fm->fc->handle_killpriv_v2 &&
35 (inarg.flags & O_TRUNC) && !capable(CAP_FSETID)) {
36 inarg.open_flags |= FUSE_OPEN_KILL_SUIDGID;
37 }
38
39 args.opcode = opcode;
40 args.nodeid = nodeid;
41 args.in_numargs = 1;
42 args.in_args[0].size = sizeof(inarg);
43 args.in_args[0].value = &inarg;
44 args.out_numargs = 1;
45 args.out_args[0].size = sizeof(*outargp);
46 args.out_args[0].value = outargp;
47
48 return fuse_simple_request(fm, &args);
49 }
50
51 struct fuse_release_args {
52 struct fuse_args args;
53 struct fuse_release_in inarg;
54 struct inode *inode;
55 };
56
57 struct fuse_file *fuse_file_alloc(struct fuse_mount *fm)
58 {
59 struct fuse_file *ff;
60
61 ff = kzalloc(sizeof(struct fuse_file), GFP_KERNEL_ACCOUNT);
62 if (unlikely(!ff))
63 return NULL;
64
65 ff->fm = fm;
66 ff->release_args = kzalloc(sizeof(*ff->release_args),
67 GFP_KERNEL_ACCOUNT);
68 if (!ff->release_args) {
69 kfree(ff);
70 return NULL;
71 }
72
73 INIT_LIST_HEAD(&ff->write_entry);
74 mutex_init(&ff->readdir.lock);
75 refcount_set(&ff->count, 1);
76 RB_CLEAR_NODE(&ff->polled_node);
77 init_waitqueue_head(&ff->poll_wait);
78
79 ff->kh = atomic64_inc_return(&fm->fc->khctr);
80
81 return ff;
82 }
83
84 void fuse_file_free(struct fuse_file *ff)
85 {
86 kfree(ff->release_args);
87 mutex_destroy(&ff->readdir.lock);
88 kfree(ff);
89 }
90
91 static struct fuse_file *fuse_file_get(struct fuse_file *ff)
92 {
93 refcount_inc(&ff->count);
94 return ff;
95 }
96
97 static void fuse_release_end(struct fuse_mount *fm, struct fuse_args *args,
98 int error)
99 {
100 struct fuse_release_args *ra = container_of(args, typeof(*ra), args);
101
102 iput(ra->inode);
103 kfree(ra);
104 }
105
106 static void fuse_file_put(struct fuse_file *ff, bool sync, bool isdir)
107 {
108 if (refcount_dec_and_test(&ff->count)) {
109 struct fuse_args *args = &ff->release_args->args;
110
111 if (isdir ? ff->fm->fc->no_opendir : ff->fm->fc->no_open) {
112 /* Do nothing when client does not implement 'open' */
113 fuse_release_end(ff->fm, args, 0);
114 } else if (sync) {
115 fuse_simple_request(ff->fm, args);
116 fuse_release_end(ff->fm, args, 0);
117 } else {
118 args->end = fuse_release_end;
119 if (fuse_simple_background(ff->fm, args,
120 GFP_KERNEL | __GFP_NOFAIL))
121 fuse_release_end(ff->fm, args, -ENOTCONN);
122 }
123 kfree(ff);
124 }
125 }
126
127 struct fuse_file *fuse_file_open(struct fuse_mount *fm, u64 nodeid,
128 unsigned int open_flags, bool isdir)
129 {
130 struct fuse_conn *fc = fm->fc;
131 struct fuse_file *ff;
132 int opcode = isdir ? FUSE_OPENDIR : FUSE_OPEN;
133
134 ff = fuse_file_alloc(fm);
135 if (!ff)
136 return ERR_PTR(-ENOMEM);
137
138 ff->fh = 0;
139 /* Default for no-open */
140 ff->open_flags = FOPEN_KEEP_CACHE | (isdir ? FOPEN_CACHE_DIR : 0);
141 if (isdir ? !fc->no_opendir : !fc->no_open) {
142 struct fuse_open_out outarg;
143 int err;
144
145 err = fuse_send_open(fm, nodeid, open_flags, opcode, &outarg);
146 if (!err) {
147 ff->fh = outarg.fh;
148 ff->open_flags = outarg.open_flags;
149
150 } else if (err != -ENOSYS) {
151 fuse_file_free(ff);
152 return ERR_PTR(err);
153 } else {
154 if (isdir)
155 fc->no_opendir = 1;
156 else
157 fc->no_open = 1;
158 }
159 }
160
161 if (isdir)
162 ff->open_flags &= ~FOPEN_DIRECT_IO;
163
164 ff->nodeid = nodeid;
165
166 return ff;
167 }
168
169 int fuse_do_open(struct fuse_mount *fm, u64 nodeid, struct file *file,
170 bool isdir)
171 {
172 struct fuse_file *ff = fuse_file_open(fm, nodeid, file->f_flags, isdir);
173
174 if (!IS_ERR(ff))
175 file->private_data = ff;
176
177 return PTR_ERR_OR_ZERO(ff);
178 }
179 EXPORT_SYMBOL_GPL(fuse_do_open);
180
181 static void fuse_link_write_file(struct file *file)
182 {
183 struct inode *inode = file_inode(file);
184 struct fuse_inode *fi = get_fuse_inode(inode);
185 struct fuse_file *ff = file->private_data;
186 /*
187 * file may be written through mmap, so chain it onto the
188 * inodes's write_file list
189 */
190 spin_lock(&fi->lock);
191 if (list_empty(&ff->write_entry))
192 list_add(&ff->write_entry, &fi->write_files);
193 spin_unlock(&fi->lock);
194 }
195
196 void fuse_finish_open(struct inode *inode, struct file *file)
197 {
198 struct fuse_file *ff = file->private_data;
199 struct fuse_conn *fc = get_fuse_conn(inode);
200
201 if (ff->open_flags & FOPEN_STREAM)
202 stream_open(inode, file);
203 else if (ff->open_flags & FOPEN_NONSEEKABLE)
204 nonseekable_open(inode, file);
205
206 if (fc->atomic_o_trunc && (file->f_flags & O_TRUNC)) {
207 struct fuse_inode *fi = get_fuse_inode(inode);
208
209 spin_lock(&fi->lock);
210 fi->attr_version = atomic64_inc_return(&fc->attr_version);
211 i_size_write(inode, 0);
212 spin_unlock(&fi->lock);
213 truncate_pagecache(inode, 0);
214 fuse_invalidate_attr(inode);
215 if (fc->writeback_cache)
216 file_update_time(file);
217 } else if (!(ff->open_flags & FOPEN_KEEP_CACHE)) {
218 invalidate_inode_pages2(inode->i_mapping);
219 }
220
221 if ((file->f_mode & FMODE_WRITE) && fc->writeback_cache)
222 fuse_link_write_file(file);
223 }
224
225 int fuse_open_common(struct inode *inode, struct file *file, bool isdir)
226 {
227 struct fuse_mount *fm = get_fuse_mount(inode);
228 struct fuse_conn *fc = fm->fc;
229 int err;
230 bool is_wb_truncate = (file->f_flags & O_TRUNC) &&
231 fc->atomic_o_trunc &&
232 fc->writeback_cache;
233 bool dax_truncate = (file->f_flags & O_TRUNC) &&
234 fc->atomic_o_trunc && FUSE_IS_DAX(inode);
235
236 if (fuse_is_bad(inode))
237 return -EIO;
238
239 err = generic_file_open(inode, file);
240 if (err)
241 return err;
242
243 if (is_wb_truncate || dax_truncate) {
244 inode_lock(inode);
245 fuse_set_nowrite(inode);
246 }
247
248 if (dax_truncate) {
249 filemap_invalidate_lock(inode->i_mapping);
250 err = fuse_dax_break_layouts(inode, 0, 0);
251 if (err)
252 goto out;
253 }
254
255 err = fuse_do_open(fm, get_node_id(inode), file, isdir);
256 if (!err)
257 fuse_finish_open(inode, file);
258
259 out:
260 if (dax_truncate)
261 filemap_invalidate_unlock(inode->i_mapping);
262
263 if (is_wb_truncate | dax_truncate) {
264 fuse_release_nowrite(inode);
265 inode_unlock(inode);
266 }
267
268 return err;
269 }
270
271 static void fuse_prepare_release(struct fuse_inode *fi, struct fuse_file *ff,
272 unsigned int flags, int opcode)
273 {
274 struct fuse_conn *fc = ff->fm->fc;
275 struct fuse_release_args *ra = ff->release_args;
276
277 /* Inode is NULL on error path of fuse_create_open() */
278 if (likely(fi)) {
279 spin_lock(&fi->lock);
280 list_del(&ff->write_entry);
281 spin_unlock(&fi->lock);
282 }
283 spin_lock(&fc->lock);
284 if (!RB_EMPTY_NODE(&ff->polled_node))
285 rb_erase(&ff->polled_node, &fc->polled_files);
286 spin_unlock(&fc->lock);
287
288 wake_up_interruptible_all(&ff->poll_wait);
289
290 ra->inarg.fh = ff->fh;
291 ra->inarg.flags = flags;
292 ra->args.in_numargs = 1;
293 ra->args.in_args[0].size = sizeof(struct fuse_release_in);
294 ra->args.in_args[0].value = &ra->inarg;
295 ra->args.opcode = opcode;
296 ra->args.nodeid = ff->nodeid;
297 ra->args.force = true;
298 ra->args.nocreds = true;
299 }
300
301 void fuse_file_release(struct inode *inode, struct fuse_file *ff,
302 unsigned int open_flags, fl_owner_t id, bool isdir)
303 {
304 struct fuse_inode *fi = get_fuse_inode(inode);
305 struct fuse_release_args *ra = ff->release_args;
306 int opcode = isdir ? FUSE_RELEASEDIR : FUSE_RELEASE;
307
308 fuse_prepare_release(fi, ff, open_flags, opcode);
309
310 if (ff->flock) {
311 ra->inarg.release_flags |= FUSE_RELEASE_FLOCK_UNLOCK;
312 ra->inarg.lock_owner = fuse_lock_owner_id(ff->fm->fc, id);
313 }
314 /* Hold inode until release is finished */
315 ra->inode = igrab(inode);
316
317 /*
318 * Normally this will send the RELEASE request, however if
319 * some asynchronous READ or WRITE requests are outstanding,
320 * the sending will be delayed.
321 *
322 * Make the release synchronous if this is a fuseblk mount,
323 * synchronous RELEASE is allowed (and desirable) in this case
324 * because the server can be trusted not to screw up.
325 */
326 fuse_file_put(ff, ff->fm->fc->destroy, isdir);
327 }
328
329 void fuse_release_common(struct file *file, bool isdir)
330 {
331 fuse_file_release(file_inode(file), file->private_data, file->f_flags,
332 (fl_owner_t) file, isdir);
333 }
334
335 static int fuse_open(struct inode *inode, struct file *file)
336 {
337 return fuse_open_common(inode, file, false);
338 }
339
340 static int fuse_release(struct inode *inode, struct file *file)
341 {
342 struct fuse_conn *fc = get_fuse_conn(inode);
343
344 /* see fuse_vma_close() for !writeback_cache case */
345 if (fc->writeback_cache)
346 write_inode_now(inode, 1);
347
348 fuse_release_common(file, false);
349
350 /* return value is ignored by VFS */
351 return 0;
352 }
353
354 void fuse_sync_release(struct fuse_inode *fi, struct fuse_file *ff,
355 unsigned int flags)
356 {
357 WARN_ON(refcount_read(&ff->count) > 1);
358 fuse_prepare_release(fi, ff, flags, FUSE_RELEASE);
359 /*
360 * iput(NULL) is a no-op and since the refcount is 1 and everything's
361 * synchronous, we are fine with not doing igrab() here"
362 */
363 fuse_file_put(ff, true, false);
364 }
365 EXPORT_SYMBOL_GPL(fuse_sync_release);
366
367 /*
368 * Scramble the ID space with XTEA, so that the value of the files_struct
369 * pointer is not exposed to userspace.
370 */
371 u64 fuse_lock_owner_id(struct fuse_conn *fc, fl_owner_t id)
372 {
373 u32 *k = fc->scramble_key;
374 u64 v = (unsigned long) id;
375 u32 v0 = v;
376 u32 v1 = v >> 32;
377 u32 sum = 0;
378 int i;
379
380 for (i = 0; i < 32; i++) {
381 v0 += ((v1 << 4 ^ v1 >> 5) + v1) ^ (sum + k[sum & 3]);
382 sum += 0x9E3779B9;
383 v1 += ((v0 << 4 ^ v0 >> 5) + v0) ^ (sum + k[sum>>11 & 3]);
384 }
385
386 return (u64) v0 + ((u64) v1 << 32);
387 }
388
389 struct fuse_writepage_args {
390 struct fuse_io_args ia;
391 struct rb_node writepages_entry;
392 struct list_head queue_entry;
393 struct fuse_writepage_args *next;
394 struct inode *inode;
395 struct fuse_sync_bucket *bucket;
396 };
397
398 static struct fuse_writepage_args *fuse_find_writeback(struct fuse_inode *fi,
399 pgoff_t idx_from, pgoff_t idx_to)
400 {
401 struct rb_node *n;
402
403 n = fi->writepages.rb_node;
404
405 while (n) {
406 struct fuse_writepage_args *wpa;
407 pgoff_t curr_index;
408
409 wpa = rb_entry(n, struct fuse_writepage_args, writepages_entry);
410 WARN_ON(get_fuse_inode(wpa->inode) != fi);
411 curr_index = wpa->ia.write.in.offset >> PAGE_SHIFT;
412 if (idx_from >= curr_index + wpa->ia.ap.num_pages)
413 n = n->rb_right;
414 else if (idx_to < curr_index)
415 n = n->rb_left;
416 else
417 return wpa;
418 }
419 return NULL;
420 }
421
422 /*
423 * Check if any page in a range is under writeback
424 *
425 * This is currently done by walking the list of writepage requests
426 * for the inode, which can be pretty inefficient.
427 */
428 static bool fuse_range_is_writeback(struct inode *inode, pgoff_t idx_from,
429 pgoff_t idx_to)
430 {
431 struct fuse_inode *fi = get_fuse_inode(inode);
432 bool found;
433
434 spin_lock(&fi->lock);
435 found = fuse_find_writeback(fi, idx_from, idx_to);
436 spin_unlock(&fi->lock);
437
438 return found;
439 }
440
441 static inline bool fuse_page_is_writeback(struct inode *inode, pgoff_t index)
442 {
443 return fuse_range_is_writeback(inode, index, index);
444 }
445
446 /*
447 * Wait for page writeback to be completed.
448 *
449 * Since fuse doesn't rely on the VM writeback tracking, this has to
450 * use some other means.
451 */
452 static void fuse_wait_on_page_writeback(struct inode *inode, pgoff_t index)
453 {
454 struct fuse_inode *fi = get_fuse_inode(inode);
455
456 wait_event(fi->page_waitq, !fuse_page_is_writeback(inode, index));
457 }
458
459 /*
460 * Wait for all pending writepages on the inode to finish.
461 *
462 * This is currently done by blocking further writes with FUSE_NOWRITE
463 * and waiting for all sent writes to complete.
464 *
465 * This must be called under i_mutex, otherwise the FUSE_NOWRITE usage
466 * could conflict with truncation.
467 */
468 static void fuse_sync_writes(struct inode *inode)
469 {
470 fuse_set_nowrite(inode);
471 fuse_release_nowrite(inode);
472 }
473
474 static int fuse_flush(struct file *file, fl_owner_t id)
475 {
476 struct inode *inode = file_inode(file);
477 struct fuse_mount *fm = get_fuse_mount(inode);
478 struct fuse_file *ff = file->private_data;
479 struct fuse_flush_in inarg;
480 FUSE_ARGS(args);
481 int err;
482
483 if (fuse_is_bad(inode))
484 return -EIO;
485
486 err = write_inode_now(inode, 1);
487 if (err)
488 return err;
489
490 inode_lock(inode);
491 fuse_sync_writes(inode);
492 inode_unlock(inode);
493
494 err = filemap_check_errors(file->f_mapping);
495 if (err)
496 return err;
497
498 err = 0;
499 if (fm->fc->no_flush)
500 goto inval_attr_out;
501
502 memset(&inarg, 0, sizeof(inarg));
503 inarg.fh = ff->fh;
504 inarg.lock_owner = fuse_lock_owner_id(fm->fc, id);
505 args.opcode = FUSE_FLUSH;
506 args.nodeid = get_node_id(inode);
507 args.in_numargs = 1;
508 args.in_args[0].size = sizeof(inarg);
509 args.in_args[0].value = &inarg;
510 args.force = true;
511
512 err = fuse_simple_request(fm, &args);
513 if (err == -ENOSYS) {
514 fm->fc->no_flush = 1;
515 err = 0;
516 }
517
518 inval_attr_out:
519 /*
520 * In memory i_blocks is not maintained by fuse, if writeback cache is
521 * enabled, i_blocks from cached attr may not be accurate.
522 */
523 if (!err && fm->fc->writeback_cache)
524 fuse_invalidate_attr(inode);
525 return err;
526 }
527
528 int fuse_fsync_common(struct file *file, loff_t start, loff_t end,
529 int datasync, int opcode)
530 {
531 struct inode *inode = file->f_mapping->host;
532 struct fuse_mount *fm = get_fuse_mount(inode);
533 struct fuse_file *ff = file->private_data;
534 FUSE_ARGS(args);
535 struct fuse_fsync_in inarg;
536
537 memset(&inarg, 0, sizeof(inarg));
538 inarg.fh = ff->fh;
539 inarg.fsync_flags = datasync ? FUSE_FSYNC_FDATASYNC : 0;
540 args.opcode = opcode;
541 args.nodeid = get_node_id(inode);
542 args.in_numargs = 1;
543 args.in_args[0].size = sizeof(inarg);
544 args.in_args[0].value = &inarg;
545 return fuse_simple_request(fm, &args);
546 }
547
548 static int fuse_fsync(struct file *file, loff_t start, loff_t end,
549 int datasync)
550 {
551 struct inode *inode = file->f_mapping->host;
552 struct fuse_conn *fc = get_fuse_conn(inode);
553 int err;
554
555 if (fuse_is_bad(inode))
556 return -EIO;
557
558 inode_lock(inode);
559
560 /*
561 * Start writeback against all dirty pages of the inode, then
562 * wait for all outstanding writes, before sending the FSYNC
563 * request.
564 */
565 err = file_write_and_wait_range(file, start, end);
566 if (err)
567 goto out;
568
569 fuse_sync_writes(inode);
570
571 /*
572 * Due to implementation of fuse writeback
573 * file_write_and_wait_range() does not catch errors.
574 * We have to do this directly after fuse_sync_writes()
575 */
576 err = file_check_and_advance_wb_err(file);
577 if (err)
578 goto out;
579
580 err = sync_inode_metadata(inode, 1);
581 if (err)
582 goto out;
583
584 if (fc->no_fsync)
585 goto out;
586
587 err = fuse_fsync_common(file, start, end, datasync, FUSE_FSYNC);
588 if (err == -ENOSYS) {
589 fc->no_fsync = 1;
590 err = 0;
591 }
592 out:
593 inode_unlock(inode);
594
595 return err;
596 }
597
598 void fuse_read_args_fill(struct fuse_io_args *ia, struct file *file, loff_t pos,
599 size_t count, int opcode)
600 {
601 struct fuse_file *ff = file->private_data;
602 struct fuse_args *args = &ia->ap.args;
603
604 ia->read.in.fh = ff->fh;
605 ia->read.in.offset = pos;
606 ia->read.in.size = count;
607 ia->read.in.flags = file->f_flags;
608 args->opcode = opcode;
609 args->nodeid = ff->nodeid;
610 args->in_numargs = 1;
611 args->in_args[0].size = sizeof(ia->read.in);
612 args->in_args[0].value = &ia->read.in;
613 args->out_argvar = true;
614 args->out_numargs = 1;
615 args->out_args[0].size = count;
616 }
617
618 static void fuse_release_user_pages(struct fuse_args_pages *ap,
619 bool should_dirty)
620 {
621 unsigned int i;
622
623 for (i = 0; i < ap->num_pages; i++) {
624 if (should_dirty)
625 set_page_dirty_lock(ap->pages[i]);
626 put_page(ap->pages[i]);
627 }
628 }
629
630 static void fuse_io_release(struct kref *kref)
631 {
632 kfree(container_of(kref, struct fuse_io_priv, refcnt));
633 }
634
635 static ssize_t fuse_get_res_by_io(struct fuse_io_priv *io)
636 {
637 if (io->err)
638 return io->err;
639
640 if (io->bytes >= 0 && io->write)
641 return -EIO;
642
643 return io->bytes < 0 ? io->size : io->bytes;
644 }
645
646 /**
647 * In case of short read, the caller sets 'pos' to the position of
648 * actual end of fuse request in IO request. Otherwise, if bytes_requested
649 * == bytes_transferred or rw == WRITE, the caller sets 'pos' to -1.
650 *
651 * An example:
652 * User requested DIO read of 64K. It was split into two 32K fuse requests,
653 * both submitted asynchronously. The first of them was ACKed by userspace as
654 * fully completed (req->out.args[0].size == 32K) resulting in pos == -1. The
655 * second request was ACKed as short, e.g. only 1K was read, resulting in
656 * pos == 33K.
657 *
658 * Thus, when all fuse requests are completed, the minimal non-negative 'pos'
659 * will be equal to the length of the longest contiguous fragment of
660 * transferred data starting from the beginning of IO request.
661 */
662 static void fuse_aio_complete(struct fuse_io_priv *io, int err, ssize_t pos)
663 {
664 int left;
665
666 spin_lock(&io->lock);
667 if (err)
668 io->err = io->err ? : err;
669 else if (pos >= 0 && (io->bytes < 0 || pos < io->bytes))
670 io->bytes = pos;
671
672 left = --io->reqs;
673 if (!left && io->blocking)
674 complete(io->done);
675 spin_unlock(&io->lock);
676
677 if (!left && !io->blocking) {
678 ssize_t res = fuse_get_res_by_io(io);
679
680 if (res >= 0) {
681 struct inode *inode = file_inode(io->iocb->ki_filp);
682 struct fuse_conn *fc = get_fuse_conn(inode);
683 struct fuse_inode *fi = get_fuse_inode(inode);
684
685 spin_lock(&fi->lock);
686 fi->attr_version = atomic64_inc_return(&fc->attr_version);
687 spin_unlock(&fi->lock);
688 }
689
690 io->iocb->ki_complete(io->iocb, res, 0);
691 }
692
693 kref_put(&io->refcnt, fuse_io_release);
694 }
695
696 static struct fuse_io_args *fuse_io_alloc(struct fuse_io_priv *io,
697 unsigned int npages)
698 {
699 struct fuse_io_args *ia;
700
701 ia = kzalloc(sizeof(*ia), GFP_KERNEL);
702 if (ia) {
703 ia->io = io;
704 ia->ap.pages = fuse_pages_alloc(npages, GFP_KERNEL,
705 &ia->ap.descs);
706 if (!ia->ap.pages) {
707 kfree(ia);
708 ia = NULL;
709 }
710 }
711 return ia;
712 }
713
714 static void fuse_io_free(struct fuse_io_args *ia)
715 {
716 kfree(ia->ap.pages);
717 kfree(ia);
718 }
719
720 static void fuse_aio_complete_req(struct fuse_mount *fm, struct fuse_args *args,
721 int err)
722 {
723 struct fuse_io_args *ia = container_of(args, typeof(*ia), ap.args);
724 struct fuse_io_priv *io = ia->io;
725 ssize_t pos = -1;
726
727 fuse_release_user_pages(&ia->ap, io->should_dirty);
728
729 if (err) {
730 /* Nothing */
731 } else if (io->write) {
732 if (ia->write.out.size > ia->write.in.size) {
733 err = -EIO;
734 } else if (ia->write.in.size != ia->write.out.size) {
735 pos = ia->write.in.offset - io->offset +
736 ia->write.out.size;
737 }
738 } else {
739 u32 outsize = args->out_args[0].size;
740
741 if (ia->read.in.size != outsize)
742 pos = ia->read.in.offset - io->offset + outsize;
743 }
744
745 fuse_aio_complete(io, err, pos);
746 fuse_io_free(ia);
747 }
748
749 static ssize_t fuse_async_req_send(struct fuse_mount *fm,
750 struct fuse_io_args *ia, size_t num_bytes)
751 {
752 ssize_t err;
753 struct fuse_io_priv *io = ia->io;
754
755 spin_lock(&io->lock);
756 kref_get(&io->refcnt);
757 io->size += num_bytes;
758 io->reqs++;
759 spin_unlock(&io->lock);
760
761 ia->ap.args.end = fuse_aio_complete_req;
762 ia->ap.args.may_block = io->should_dirty;
763 err = fuse_simple_background(fm, &ia->ap.args, GFP_KERNEL);
764 if (err)
765 fuse_aio_complete_req(fm, &ia->ap.args, err);
766
767 return num_bytes;
768 }
769
770 static ssize_t fuse_send_read(struct fuse_io_args *ia, loff_t pos, size_t count,
771 fl_owner_t owner)
772 {
773 struct file *file = ia->io->iocb->ki_filp;
774 struct fuse_file *ff = file->private_data;
775 struct fuse_mount *fm = ff->fm;
776
777 fuse_read_args_fill(ia, file, pos, count, FUSE_READ);
778 if (owner != NULL) {
779 ia->read.in.read_flags |= FUSE_READ_LOCKOWNER;
780 ia->read.in.lock_owner = fuse_lock_owner_id(fm->fc, owner);
781 }
782
783 if (ia->io->async)
784 return fuse_async_req_send(fm, ia, count);
785
786 return fuse_simple_request(fm, &ia->ap.args);
787 }
788
789 static void fuse_read_update_size(struct inode *inode, loff_t size,
790 u64 attr_ver)
791 {
792 struct fuse_conn *fc = get_fuse_conn(inode);
793 struct fuse_inode *fi = get_fuse_inode(inode);
794
795 spin_lock(&fi->lock);
796 if (attr_ver == fi->attr_version && size < inode->i_size &&
797 !test_bit(FUSE_I_SIZE_UNSTABLE, &fi->state)) {
798 fi->attr_version = atomic64_inc_return(&fc->attr_version);
799 i_size_write(inode, size);
800 }
801 spin_unlock(&fi->lock);
802 }
803
804 static void fuse_short_read(struct inode *inode, u64 attr_ver, size_t num_read,
805 struct fuse_args_pages *ap)
806 {
807 struct fuse_conn *fc = get_fuse_conn(inode);
808
809 /*
810 * If writeback_cache is enabled, a short read means there's a hole in
811 * the file. Some data after the hole is in page cache, but has not
812 * reached the client fs yet. So the hole is not present there.
813 */
814 if (!fc->writeback_cache) {
815 loff_t pos = page_offset(ap->pages[0]) + num_read;
816 fuse_read_update_size(inode, pos, attr_ver);
817 }
818 }
819
820 static int fuse_do_readpage(struct file *file, struct page *page)
821 {
822 struct inode *inode = page->mapping->host;
823 struct fuse_mount *fm = get_fuse_mount(inode);
824 loff_t pos = page_offset(page);
825 struct fuse_page_desc desc = { .length = PAGE_SIZE };
826 struct fuse_io_args ia = {
827 .ap.args.page_zeroing = true,
828 .ap.args.out_pages = true,
829 .ap.num_pages = 1,
830 .ap.pages = &page,
831 .ap.descs = &desc,
832 };
833 ssize_t res;
834 u64 attr_ver;
835
836 /*
837 * Page writeback can extend beyond the lifetime of the
838 * page-cache page, so make sure we read a properly synced
839 * page.
840 */
841 fuse_wait_on_page_writeback(inode, page->index);
842
843 attr_ver = fuse_get_attr_version(fm->fc);
844
845 /* Don't overflow end offset */
846 if (pos + (desc.length - 1) == LLONG_MAX)
847 desc.length--;
848
849 fuse_read_args_fill(&ia, file, pos, desc.length, FUSE_READ);
850 res = fuse_simple_request(fm, &ia.ap.args);
851 if (res < 0)
852 return res;
853 /*
854 * Short read means EOF. If file size is larger, truncate it
855 */
856 if (res < desc.length)
857 fuse_short_read(inode, attr_ver, res, &ia.ap);
858
859 SetPageUptodate(page);
860
861 return 0;
862 }
863
864 static int fuse_readpage(struct file *file, struct page *page)
865 {
866 struct inode *inode = page->mapping->host;
867 int err;
868
869 err = -EIO;
870 if (fuse_is_bad(inode))
871 goto out;
872
873 err = fuse_do_readpage(file, page);
874 fuse_invalidate_atime(inode);
875 out:
876 unlock_page(page);
877 return err;
878 }
879
880 static void fuse_readpages_end(struct fuse_mount *fm, struct fuse_args *args,
881 int err)
882 {
883 int i;
884 struct fuse_io_args *ia = container_of(args, typeof(*ia), ap.args);
885 struct fuse_args_pages *ap = &ia->ap;
886 size_t count = ia->read.in.size;
887 size_t num_read = args->out_args[0].size;
888 struct address_space *mapping = NULL;
889
890 for (i = 0; mapping == NULL && i < ap->num_pages; i++)
891 mapping = ap->pages[i]->mapping;
892
893 if (mapping) {
894 struct inode *inode = mapping->host;
895
896 /*
897 * Short read means EOF. If file size is larger, truncate it
898 */
899 if (!err && num_read < count)
900 fuse_short_read(inode, ia->read.attr_ver, num_read, ap);
901
902 fuse_invalidate_atime(inode);
903 }
904
905 for (i = 0; i < ap->num_pages; i++) {
906 struct page *page = ap->pages[i];
907
908 if (!err)
909 SetPageUptodate(page);
910 else
911 SetPageError(page);
912 unlock_page(page);
913 put_page(page);
914 }
915 if (ia->ff)
916 fuse_file_put(ia->ff, false, false);
917
918 fuse_io_free(ia);
919 }
920
921 static void fuse_send_readpages(struct fuse_io_args *ia, struct file *file)
922 {
923 struct fuse_file *ff = file->private_data;
924 struct fuse_mount *fm = ff->fm;
925 struct fuse_args_pages *ap = &ia->ap;
926 loff_t pos = page_offset(ap->pages[0]);
927 size_t count = ap->num_pages << PAGE_SHIFT;
928 ssize_t res;
929 int err;
930
931 ap->args.out_pages = true;
932 ap->args.page_zeroing = true;
933 ap->args.page_replace = true;
934
935 /* Don't overflow end offset */
936 if (pos + (count - 1) == LLONG_MAX) {
937 count--;
938 ap->descs[ap->num_pages - 1].length--;
939 }
940 WARN_ON((loff_t) (pos + count) < 0);
941
942 fuse_read_args_fill(ia, file, pos, count, FUSE_READ);
943 ia->read.attr_ver = fuse_get_attr_version(fm->fc);
944 if (fm->fc->async_read) {
945 ia->ff = fuse_file_get(ff);
946 ap->args.end = fuse_readpages_end;
947 err = fuse_simple_background(fm, &ap->args, GFP_KERNEL);
948 if (!err)
949 return;
950 } else {
951 res = fuse_simple_request(fm, &ap->args);
952 err = res < 0 ? res : 0;
953 }
954 fuse_readpages_end(fm, &ap->args, err);
955 }
956
957 static void fuse_readahead(struct readahead_control *rac)
958 {
959 struct inode *inode = rac->mapping->host;
960 struct fuse_conn *fc = get_fuse_conn(inode);
961 unsigned int i, max_pages, nr_pages = 0;
962
963 if (fuse_is_bad(inode))
964 return;
965
966 max_pages = min_t(unsigned int, fc->max_pages,
967 fc->max_read / PAGE_SIZE);
968
969 for (;;) {
970 struct fuse_io_args *ia;
971 struct fuse_args_pages *ap;
972
973 nr_pages = readahead_count(rac) - nr_pages;
974 if (nr_pages > max_pages)
975 nr_pages = max_pages;
976 if (nr_pages == 0)
977 break;
978 ia = fuse_io_alloc(NULL, nr_pages);
979 if (!ia)
980 return;
981 ap = &ia->ap;
982 nr_pages = __readahead_batch(rac, ap->pages, nr_pages);
983 for (i = 0; i < nr_pages; i++) {
984 fuse_wait_on_page_writeback(inode,
985 readahead_index(rac) + i);
986 ap->descs[i].length = PAGE_SIZE;
987 }
988 ap->num_pages = nr_pages;
989 fuse_send_readpages(ia, rac->file);
990 }
991 }
992
993 static ssize_t fuse_cache_read_iter(struct kiocb *iocb, struct iov_iter *to)
994 {
995 struct inode *inode = iocb->ki_filp->f_mapping->host;
996 struct fuse_conn *fc = get_fuse_conn(inode);
997
998 /*
999 * In auto invalidate mode, always update attributes on read.
1000 * Otherwise, only update if we attempt to read past EOF (to ensure
1001 * i_size is up to date).
1002 */
1003 if (fc->auto_inval_data ||
1004 (iocb->ki_pos + iov_iter_count(to) > i_size_read(inode))) {
1005 int err;
1006 err = fuse_update_attributes(inode, iocb->ki_filp);
1007 if (err)
1008 return err;
1009 }
1010
1011 return generic_file_read_iter(iocb, to);
1012 }
1013
1014 static void fuse_write_args_fill(struct fuse_io_args *ia, struct fuse_file *ff,
1015 loff_t pos, size_t count)
1016 {
1017 struct fuse_args *args = &ia->ap.args;
1018
1019 ia->write.in.fh = ff->fh;
1020 ia->write.in.offset = pos;
1021 ia->write.in.size = count;
1022 args->opcode = FUSE_WRITE;
1023 args->nodeid = ff->nodeid;
1024 args->in_numargs = 2;
1025 if (ff->fm->fc->minor < 9)
1026 args->in_args[0].size = FUSE_COMPAT_WRITE_IN_SIZE;
1027 else
1028 args->in_args[0].size = sizeof(ia->write.in);
1029 args->in_args[0].value = &ia->write.in;
1030 args->in_args[1].size = count;
1031 args->out_numargs = 1;
1032 args->out_args[0].size = sizeof(ia->write.out);
1033 args->out_args[0].value = &ia->write.out;
1034 }
1035
1036 static unsigned int fuse_write_flags(struct kiocb *iocb)
1037 {
1038 unsigned int flags = iocb->ki_filp->f_flags;
1039
1040 if (iocb->ki_flags & IOCB_DSYNC)
1041 flags |= O_DSYNC;
1042 if (iocb->ki_flags & IOCB_SYNC)
1043 flags |= O_SYNC;
1044
1045 return flags;
1046 }
1047
1048 static ssize_t fuse_send_write(struct fuse_io_args *ia, loff_t pos,
1049 size_t count, fl_owner_t owner)
1050 {
1051 struct kiocb *iocb = ia->io->iocb;
1052 struct file *file = iocb->ki_filp;
1053 struct fuse_file *ff = file->private_data;
1054 struct fuse_mount *fm = ff->fm;
1055 struct fuse_write_in *inarg = &ia->write.in;
1056 ssize_t err;
1057
1058 fuse_write_args_fill(ia, ff, pos, count);
1059 inarg->flags = fuse_write_flags(iocb);
1060 if (owner != NULL) {
1061 inarg->write_flags |= FUSE_WRITE_LOCKOWNER;
1062 inarg->lock_owner = fuse_lock_owner_id(fm->fc, owner);
1063 }
1064
1065 if (ia->io->async)
1066 return fuse_async_req_send(fm, ia, count);
1067
1068 err = fuse_simple_request(fm, &ia->ap.args);
1069 if (!err && ia->write.out.size > count)
1070 err = -EIO;
1071
1072 return err ?: ia->write.out.size;
1073 }
1074
1075 bool fuse_write_update_size(struct inode *inode, loff_t pos)
1076 {
1077 struct fuse_conn *fc = get_fuse_conn(inode);
1078 struct fuse_inode *fi = get_fuse_inode(inode);
1079 bool ret = false;
1080
1081 spin_lock(&fi->lock);
1082 fi->attr_version = atomic64_inc_return(&fc->attr_version);
1083 if (pos > inode->i_size) {
1084 i_size_write(inode, pos);
1085 ret = true;
1086 }
1087 spin_unlock(&fi->lock);
1088
1089 return ret;
1090 }
1091
1092 static ssize_t fuse_send_write_pages(struct fuse_io_args *ia,
1093 struct kiocb *iocb, struct inode *inode,
1094 loff_t pos, size_t count)
1095 {
1096 struct fuse_args_pages *ap = &ia->ap;
1097 struct file *file = iocb->ki_filp;
1098 struct fuse_file *ff = file->private_data;
1099 struct fuse_mount *fm = ff->fm;
1100 unsigned int offset, i;
1101 bool short_write;
1102 int err;
1103
1104 for (i = 0; i < ap->num_pages; i++)
1105 fuse_wait_on_page_writeback(inode, ap->pages[i]->index);
1106
1107 fuse_write_args_fill(ia, ff, pos, count);
1108 ia->write.in.flags = fuse_write_flags(iocb);
1109 if (fm->fc->handle_killpriv_v2 && !capable(CAP_FSETID))
1110 ia->write.in.write_flags |= FUSE_WRITE_KILL_SUIDGID;
1111
1112 err = fuse_simple_request(fm, &ap->args);
1113 if (!err && ia->write.out.size > count)
1114 err = -EIO;
1115
1116 short_write = ia->write.out.size < count;
1117 offset = ap->descs[0].offset;
1118 count = ia->write.out.size;
1119 for (i = 0; i < ap->num_pages; i++) {
1120 struct page *page = ap->pages[i];
1121
1122 if (err) {
1123 ClearPageUptodate(page);
1124 } else {
1125 if (count >= PAGE_SIZE - offset)
1126 count -= PAGE_SIZE - offset;
1127 else {
1128 if (short_write)
1129 ClearPageUptodate(page);
1130 count = 0;
1131 }
1132 offset = 0;
1133 }
1134 if (ia->write.page_locked && (i == ap->num_pages - 1))
1135 unlock_page(page);
1136 put_page(page);
1137 }
1138
1139 return err;
1140 }
1141
1142 static ssize_t fuse_fill_write_pages(struct fuse_io_args *ia,
1143 struct address_space *mapping,
1144 struct iov_iter *ii, loff_t pos,
1145 unsigned int max_pages)
1146 {
1147 struct fuse_args_pages *ap = &ia->ap;
1148 struct fuse_conn *fc = get_fuse_conn(mapping->host);
1149 unsigned offset = pos & (PAGE_SIZE - 1);
1150 size_t count = 0;
1151 int err;
1152
1153 ap->args.in_pages = true;
1154 ap->descs[0].offset = offset;
1155
1156 do {
1157 size_t tmp;
1158 struct page *page;
1159 pgoff_t index = pos >> PAGE_SHIFT;
1160 size_t bytes = min_t(size_t, PAGE_SIZE - offset,
1161 iov_iter_count(ii));
1162
1163 bytes = min_t(size_t, bytes, fc->max_write - count);
1164
1165 again:
1166 err = -EFAULT;
1167 if (iov_iter_fault_in_readable(ii, bytes))
1168 break;
1169
1170 err = -ENOMEM;
1171 page = grab_cache_page_write_begin(mapping, index, 0);
1172 if (!page)
1173 break;
1174
1175 if (mapping_writably_mapped(mapping))
1176 flush_dcache_page(page);
1177
1178 tmp = copy_page_from_iter_atomic(page, offset, bytes, ii);
1179 flush_dcache_page(page);
1180
1181 if (!tmp) {
1182 unlock_page(page);
1183 put_page(page);
1184 goto again;
1185 }
1186
1187 err = 0;
1188 ap->pages[ap->num_pages] = page;
1189 ap->descs[ap->num_pages].length = tmp;
1190 ap->num_pages++;
1191
1192 count += tmp;
1193 pos += tmp;
1194 offset += tmp;
1195 if (offset == PAGE_SIZE)
1196 offset = 0;
1197
1198 /* If we copied full page, mark it uptodate */
1199 if (tmp == PAGE_SIZE)
1200 SetPageUptodate(page);
1201
1202 if (PageUptodate(page)) {
1203 unlock_page(page);
1204 } else {
1205 ia->write.page_locked = true;
1206 break;
1207 }
1208 if (!fc->big_writes)
1209 break;
1210 } while (iov_iter_count(ii) && count < fc->max_write &&
1211 ap->num_pages < max_pages && offset == 0);
1212
1213 return count > 0 ? count : err;
1214 }
1215
1216 static inline unsigned int fuse_wr_pages(loff_t pos, size_t len,
1217 unsigned int max_pages)
1218 {
1219 return min_t(unsigned int,
1220 ((pos + len - 1) >> PAGE_SHIFT) -
1221 (pos >> PAGE_SHIFT) + 1,
1222 max_pages);
1223 }
1224
1225 static ssize_t fuse_perform_write(struct kiocb *iocb,
1226 struct address_space *mapping,
1227 struct iov_iter *ii, loff_t pos)
1228 {
1229 struct inode *inode = mapping->host;
1230 struct fuse_conn *fc = get_fuse_conn(inode);
1231 struct fuse_inode *fi = get_fuse_inode(inode);
1232 int err = 0;
1233 ssize_t res = 0;
1234
1235 if (inode->i_size < pos + iov_iter_count(ii))
1236 set_bit(FUSE_I_SIZE_UNSTABLE, &fi->state);
1237
1238 do {
1239 ssize_t count;
1240 struct fuse_io_args ia = {};
1241 struct fuse_args_pages *ap = &ia.ap;
1242 unsigned int nr_pages = fuse_wr_pages(pos, iov_iter_count(ii),
1243 fc->max_pages);
1244
1245 ap->pages = fuse_pages_alloc(nr_pages, GFP_KERNEL, &ap->descs);
1246 if (!ap->pages) {
1247 err = -ENOMEM;
1248 break;
1249 }
1250
1251 count = fuse_fill_write_pages(&ia, mapping, ii, pos, nr_pages);
1252 if (count <= 0) {
1253 err = count;
1254 } else {
1255 err = fuse_send_write_pages(&ia, iocb, inode,
1256 pos, count);
1257 if (!err) {
1258 size_t num_written = ia.write.out.size;
1259
1260 res += num_written;
1261 pos += num_written;
1262
1263 /* break out of the loop on short write */
1264 if (num_written != count)
1265 err = -EIO;
1266 }
1267 }
1268 kfree(ap->pages);
1269 } while (!err && iov_iter_count(ii));
1270
1271 if (res > 0)
1272 fuse_write_update_size(inode, pos);
1273
1274 clear_bit(FUSE_I_SIZE_UNSTABLE, &fi->state);
1275 fuse_invalidate_attr(inode);
1276
1277 return res > 0 ? res : err;
1278 }
1279
1280 static ssize_t fuse_cache_write_iter(struct kiocb *iocb, struct iov_iter *from)
1281 {
1282 struct file *file = iocb->ki_filp;
1283 struct address_space *mapping = file->f_mapping;
1284 ssize_t written = 0;
1285 ssize_t written_buffered = 0;
1286 struct inode *inode = mapping->host;
1287 ssize_t err;
1288 struct fuse_conn *fc = get_fuse_conn(inode);
1289 loff_t endbyte = 0;
1290
1291 if (fc->writeback_cache) {
1292 /* Update size (EOF optimization) and mode (SUID clearing) */
1293 err = fuse_update_attributes(mapping->host, file);
1294 if (err)
1295 return err;
1296
1297 if (fc->handle_killpriv_v2 &&
1298 should_remove_suid(file_dentry(file))) {
1299 goto writethrough;
1300 }
1301
1302 return generic_file_write_iter(iocb, from);
1303 }
1304
1305 writethrough:
1306 inode_lock(inode);
1307
1308 /* We can write back this queue in page reclaim */
1309 current->backing_dev_info = inode_to_bdi(inode);
1310
1311 err = generic_write_checks(iocb, from);
1312 if (err <= 0)
1313 goto out;
1314
1315 err = file_remove_privs(file);
1316 if (err)
1317 goto out;
1318
1319 err = file_update_time(file);
1320 if (err)
1321 goto out;
1322
1323 if (iocb->ki_flags & IOCB_DIRECT) {
1324 loff_t pos = iocb->ki_pos;
1325 written = generic_file_direct_write(iocb, from);
1326 if (written < 0 || !iov_iter_count(from))
1327 goto out;
1328
1329 pos += written;
1330
1331 written_buffered = fuse_perform_write(iocb, mapping, from, pos);
1332 if (written_buffered < 0) {
1333 err = written_buffered;
1334 goto out;
1335 }
1336 endbyte = pos + written_buffered - 1;
1337
1338 err = filemap_write_and_wait_range(file->f_mapping, pos,
1339 endbyte);
1340 if (err)
1341 goto out;
1342
1343 invalidate_mapping_pages(file->f_mapping,
1344 pos >> PAGE_SHIFT,
1345 endbyte >> PAGE_SHIFT);
1346
1347 written += written_buffered;
1348 iocb->ki_pos = pos + written_buffered;
1349 } else {
1350 written = fuse_perform_write(iocb, mapping, from, iocb->ki_pos);
1351 if (written >= 0)
1352 iocb->ki_pos += written;
1353 }
1354 out:
1355 current->backing_dev_info = NULL;
1356 inode_unlock(inode);
1357 if (written > 0)
1358 written = generic_write_sync(iocb, written);
1359
1360 return written ? written : err;
1361 }
1362
1363 static inline unsigned long fuse_get_user_addr(const struct iov_iter *ii)
1364 {
1365 return (unsigned long)ii->iov->iov_base + ii->iov_offset;
1366 }
1367
1368 static inline size_t fuse_get_frag_size(const struct iov_iter *ii,
1369 size_t max_size)
1370 {
1371 return min(iov_iter_single_seg_count(ii), max_size);
1372 }
1373
1374 static int fuse_get_user_pages(struct fuse_args_pages *ap, struct iov_iter *ii,
1375 size_t *nbytesp, int write,
1376 unsigned int max_pages)
1377 {
1378 size_t nbytes = 0; /* # bytes already packed in req */
1379 ssize_t ret = 0;
1380
1381 /* Special case for kernel I/O: can copy directly into the buffer */
1382 if (iov_iter_is_kvec(ii)) {
1383 unsigned long user_addr = fuse_get_user_addr(ii);
1384 size_t frag_size = fuse_get_frag_size(ii, *nbytesp);
1385
1386 if (write)
1387 ap->args.in_args[1].value = (void *) user_addr;
1388 else
1389 ap->args.out_args[0].value = (void *) user_addr;
1390
1391 iov_iter_advance(ii, frag_size);
1392 *nbytesp = frag_size;
1393 return 0;
1394 }
1395
1396 while (nbytes < *nbytesp && ap->num_pages < max_pages) {
1397 unsigned npages;
1398 size_t start;
1399 ret = iov_iter_get_pages(ii, &ap->pages[ap->num_pages],
1400 *nbytesp - nbytes,
1401 max_pages - ap->num_pages,
1402 &start);
1403 if (ret < 0)
1404 break;
1405
1406 iov_iter_advance(ii, ret);
1407 nbytes += ret;
1408
1409 ret += start;
1410 npages = DIV_ROUND_UP(ret, PAGE_SIZE);
1411
1412 ap->descs[ap->num_pages].offset = start;
1413 fuse_page_descs_length_init(ap->descs, ap->num_pages, npages);
1414
1415 ap->num_pages += npages;
1416 ap->descs[ap->num_pages - 1].length -=
1417 (PAGE_SIZE - ret) & (PAGE_SIZE - 1);
1418 }
1419
1420 if (write)
1421 ap->args.in_pages = true;
1422 else
1423 ap->args.out_pages = true;
1424
1425 *nbytesp = nbytes;
1426
1427 return ret < 0 ? ret : 0;
1428 }
1429
1430 ssize_t fuse_direct_io(struct fuse_io_priv *io, struct iov_iter *iter,
1431 loff_t *ppos, int flags)
1432 {
1433 int write = flags & FUSE_DIO_WRITE;
1434 int cuse = flags & FUSE_DIO_CUSE;
1435 struct file *file = io->iocb->ki_filp;
1436 struct inode *inode = file->f_mapping->host;
1437 struct fuse_file *ff = file->private_data;
1438 struct fuse_conn *fc = ff->fm->fc;
1439 size_t nmax = write ? fc->max_write : fc->max_read;
1440 loff_t pos = *ppos;
1441 size_t count = iov_iter_count(iter);
1442 pgoff_t idx_from = pos >> PAGE_SHIFT;
1443 pgoff_t idx_to = (pos + count - 1) >> PAGE_SHIFT;
1444 ssize_t res = 0;
1445 int err = 0;
1446 struct fuse_io_args *ia;
1447 unsigned int max_pages;
1448
1449 max_pages = iov_iter_npages(iter, fc->max_pages);
1450 ia = fuse_io_alloc(io, max_pages);
1451 if (!ia)
1452 return -ENOMEM;
1453
1454 ia->io = io;
1455 if (!cuse && fuse_range_is_writeback(inode, idx_from, idx_to)) {
1456 if (!write)
1457 inode_lock(inode);
1458 fuse_sync_writes(inode);
1459 if (!write)
1460 inode_unlock(inode);
1461 }
1462
1463 io->should_dirty = !write && iter_is_iovec(iter);
1464 while (count) {
1465 ssize_t nres;
1466 fl_owner_t owner = current->files;
1467 size_t nbytes = min(count, nmax);
1468
1469 err = fuse_get_user_pages(&ia->ap, iter, &nbytes, write,
1470 max_pages);
1471 if (err && !nbytes)
1472 break;
1473
1474 if (write) {
1475 if (!capable(CAP_FSETID))
1476 ia->write.in.write_flags |= FUSE_WRITE_KILL_SUIDGID;
1477
1478 nres = fuse_send_write(ia, pos, nbytes, owner);
1479 } else {
1480 nres = fuse_send_read(ia, pos, nbytes, owner);
1481 }
1482
1483 if (!io->async || nres < 0) {
1484 fuse_release_user_pages(&ia->ap, io->should_dirty);
1485 fuse_io_free(ia);
1486 }
1487 ia = NULL;
1488 if (nres < 0) {
1489 iov_iter_revert(iter, nbytes);
1490 err = nres;
1491 break;
1492 }
1493 WARN_ON(nres > nbytes);
1494
1495 count -= nres;
1496 res += nres;
1497 pos += nres;
1498 if (nres != nbytes) {
1499 iov_iter_revert(iter, nbytes - nres);
1500 break;
1501 }
1502 if (count) {
1503 max_pages = iov_iter_npages(iter, fc->max_pages);
1504 ia = fuse_io_alloc(io, max_pages);
1505 if (!ia)
1506 break;
1507 }
1508 }
1509 if (ia)
1510 fuse_io_free(ia);
1511 if (res > 0)
1512 *ppos = pos;
1513
1514 return res > 0 ? res : err;
1515 }
1516 EXPORT_SYMBOL_GPL(fuse_direct_io);
1517
1518 static ssize_t __fuse_direct_read(struct fuse_io_priv *io,
1519 struct iov_iter *iter,
1520 loff_t *ppos)
1521 {
1522 ssize_t res;
1523 struct inode *inode = file_inode(io->iocb->ki_filp);
1524
1525 res = fuse_direct_io(io, iter, ppos, 0);
1526
1527 fuse_invalidate_atime(inode);
1528
1529 return res;
1530 }
1531
1532 static ssize_t fuse_direct_IO(struct kiocb *iocb, struct iov_iter *iter);
1533
1534 static ssize_t fuse_direct_read_iter(struct kiocb *iocb, struct iov_iter *to)
1535 {
1536 ssize_t res;
1537
1538 if (!is_sync_kiocb(iocb) && iocb->ki_flags & IOCB_DIRECT) {
1539 res = fuse_direct_IO(iocb, to);
1540 } else {
1541 struct fuse_io_priv io = FUSE_IO_PRIV_SYNC(iocb);
1542
1543 res = __fuse_direct_read(&io, to, &iocb->ki_pos);
1544 }
1545
1546 return res;
1547 }
1548
1549 static ssize_t fuse_direct_write_iter(struct kiocb *iocb, struct iov_iter *from)
1550 {
1551 struct inode *inode = file_inode(iocb->ki_filp);
1552 struct fuse_io_priv io = FUSE_IO_PRIV_SYNC(iocb);
1553 ssize_t res;
1554
1555 /* Don't allow parallel writes to the same file */
1556 inode_lock(inode);
1557 res = generic_write_checks(iocb, from);
1558 if (res > 0) {
1559 if (!is_sync_kiocb(iocb) && iocb->ki_flags & IOCB_DIRECT) {
1560 res = fuse_direct_IO(iocb, from);
1561 } else {
1562 res = fuse_direct_io(&io, from, &iocb->ki_pos,
1563 FUSE_DIO_WRITE);
1564 }
1565 }
1566 fuse_invalidate_attr(inode);
1567 if (res > 0)
1568 fuse_write_update_size(inode, iocb->ki_pos);
1569 inode_unlock(inode);
1570
1571 return res;
1572 }
1573
1574 static ssize_t fuse_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
1575 {
1576 struct file *file = iocb->ki_filp;
1577 struct fuse_file *ff = file->private_data;
1578 struct inode *inode = file_inode(file);
1579
1580 if (fuse_is_bad(inode))
1581 return -EIO;
1582
1583 if (FUSE_IS_DAX(inode))
1584 return fuse_dax_read_iter(iocb, to);
1585
1586 if (!(ff->open_flags & FOPEN_DIRECT_IO))
1587 return fuse_cache_read_iter(iocb, to);
1588 else
1589 return fuse_direct_read_iter(iocb, to);
1590 }
1591
1592 static ssize_t fuse_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
1593 {
1594 struct file *file = iocb->ki_filp;
1595 struct fuse_file *ff = file->private_data;
1596 struct inode *inode = file_inode(file);
1597
1598 if (fuse_is_bad(inode))
1599 return -EIO;
1600
1601 if (FUSE_IS_DAX(inode))
1602 return fuse_dax_write_iter(iocb, from);
1603
1604 if (!(ff->open_flags & FOPEN_DIRECT_IO))
1605 return fuse_cache_write_iter(iocb, from);
1606 else
1607 return fuse_direct_write_iter(iocb, from);
1608 }
1609
1610 static void fuse_writepage_free(struct fuse_writepage_args *wpa)
1611 {
1612 struct fuse_args_pages *ap = &wpa->ia.ap;
1613 int i;
1614
1615 if (wpa->bucket)
1616 fuse_sync_bucket_dec(wpa->bucket);
1617
1618 for (i = 0; i < ap->num_pages; i++)
1619 __free_page(ap->pages[i]);
1620
1621 if (wpa->ia.ff)
1622 fuse_file_put(wpa->ia.ff, false, false);
1623
1624 kfree(ap->pages);
1625 kfree(wpa);
1626 }
1627
1628 static void fuse_writepage_finish(struct fuse_mount *fm,
1629 struct fuse_writepage_args *wpa)
1630 {
1631 struct fuse_args_pages *ap = &wpa->ia.ap;
1632 struct inode *inode = wpa->inode;
1633 struct fuse_inode *fi = get_fuse_inode(inode);
1634 struct backing_dev_info *bdi = inode_to_bdi(inode);
1635 int i;
1636
1637 for (i = 0; i < ap->num_pages; i++) {
1638 dec_wb_stat(&bdi->wb, WB_WRITEBACK);
1639 dec_node_page_state(ap->pages[i], NR_WRITEBACK_TEMP);
1640 wb_writeout_inc(&bdi->wb);
1641 }
1642 wake_up(&fi->page_waitq);
1643 }
1644
1645 /* Called under fi->lock, may release and reacquire it */
1646 static void fuse_send_writepage(struct fuse_mount *fm,
1647 struct fuse_writepage_args *wpa, loff_t size)
1648 __releases(fi->lock)
1649 __acquires(fi->lock)
1650 {
1651 struct fuse_writepage_args *aux, *next;
1652 struct fuse_inode *fi = get_fuse_inode(wpa->inode);
1653 struct fuse_write_in *inarg = &wpa->ia.write.in;
1654 struct fuse_args *args = &wpa->ia.ap.args;
1655 __u64 data_size = wpa->ia.ap.num_pages * PAGE_SIZE;
1656 int err;
1657
1658 fi->writectr++;
1659 if (inarg->offset + data_size <= size) {
1660 inarg->size = data_size;
1661 } else if (inarg->offset < size) {
1662 inarg->size = size - inarg->offset;
1663 } else {
1664 /* Got truncated off completely */
1665 goto out_free;
1666 }
1667
1668 args->in_args[1].size = inarg->size;
1669 args->force = true;
1670 args->nocreds = true;
1671
1672 err = fuse_simple_background(fm, args, GFP_ATOMIC);
1673 if (err == -ENOMEM) {
1674 spin_unlock(&fi->lock);
1675 err = fuse_simple_background(fm, args, GFP_NOFS | __GFP_NOFAIL);
1676 spin_lock(&fi->lock);
1677 }
1678
1679 /* Fails on broken connection only */
1680 if (unlikely(err))
1681 goto out_free;
1682
1683 return;
1684
1685 out_free:
1686 fi->writectr--;
1687 rb_erase(&wpa->writepages_entry, &fi->writepages);
1688 fuse_writepage_finish(fm, wpa);
1689 spin_unlock(&fi->lock);
1690
1691 /* After fuse_writepage_finish() aux request list is private */
1692 for (aux = wpa->next; aux; aux = next) {
1693 next = aux->next;
1694 aux->next = NULL;
1695 fuse_writepage_free(aux);
1696 }
1697
1698 fuse_writepage_free(wpa);
1699 spin_lock(&fi->lock);
1700 }
1701
1702 /*
1703 * If fi->writectr is positive (no truncate or fsync going on) send
1704 * all queued writepage requests.
1705 *
1706 * Called with fi->lock
1707 */
1708 void fuse_flush_writepages(struct inode *inode)
1709 __releases(fi->lock)
1710 __acquires(fi->lock)
1711 {
1712 struct fuse_mount *fm = get_fuse_mount(inode);
1713 struct fuse_inode *fi = get_fuse_inode(inode);
1714 loff_t crop = i_size_read(inode);
1715 struct fuse_writepage_args *wpa;
1716
1717 while (fi->writectr >= 0 && !list_empty(&fi->queued_writes)) {
1718 wpa = list_entry(fi->queued_writes.next,
1719 struct fuse_writepage_args, queue_entry);
1720 list_del_init(&wpa->queue_entry);
1721 fuse_send_writepage(fm, wpa, crop);
1722 }
1723 }
1724
1725 static struct fuse_writepage_args *fuse_insert_writeback(struct rb_root *root,
1726 struct fuse_writepage_args *wpa)
1727 {
1728 pgoff_t idx_from = wpa->ia.write.in.offset >> PAGE_SHIFT;
1729 pgoff_t idx_to = idx_from + wpa->ia.ap.num_pages - 1;
1730 struct rb_node **p = &root->rb_node;
1731 struct rb_node *parent = NULL;
1732
1733 WARN_ON(!wpa->ia.ap.num_pages);
1734 while (*p) {
1735 struct fuse_writepage_args *curr;
1736 pgoff_t curr_index;
1737
1738 parent = *p;
1739 curr = rb_entry(parent, struct fuse_writepage_args,
1740 writepages_entry);
1741 WARN_ON(curr->inode != wpa->inode);
1742 curr_index = curr->ia.write.in.offset >> PAGE_SHIFT;
1743
1744 if (idx_from >= curr_index + curr->ia.ap.num_pages)
1745 p = &(*p)->rb_right;
1746 else if (idx_to < curr_index)
1747 p = &(*p)->rb_left;
1748 else
1749 return curr;
1750 }
1751
1752 rb_link_node(&wpa->writepages_entry, parent, p);
1753 rb_insert_color(&wpa->writepages_entry, root);
1754 return NULL;
1755 }
1756
1757 static void tree_insert(struct rb_root *root, struct fuse_writepage_args *wpa)
1758 {
1759 WARN_ON(fuse_insert_writeback(root, wpa));
1760 }
1761
1762 static void fuse_writepage_end(struct fuse_mount *fm, struct fuse_args *args,
1763 int error)
1764 {
1765 struct fuse_writepage_args *wpa =
1766 container_of(args, typeof(*wpa), ia.ap.args);
1767 struct inode *inode = wpa->inode;
1768 struct fuse_inode *fi = get_fuse_inode(inode);
1769 struct fuse_conn *fc = get_fuse_conn(inode);
1770
1771 mapping_set_error(inode->i_mapping, error);
1772 /*
1773 * A writeback finished and this might have updated mtime/ctime on
1774 * server making local mtime/ctime stale. Hence invalidate attrs.
1775 * Do this only if writeback_cache is not enabled. If writeback_cache
1776 * is enabled, we trust local ctime/mtime.
1777 */
1778 if (!fc->writeback_cache)
1779 fuse_invalidate_attr(inode);
1780 spin_lock(&fi->lock);
1781 rb_erase(&wpa->writepages_entry, &fi->writepages);
1782 while (wpa->next) {
1783 struct fuse_mount *fm = get_fuse_mount(inode);
1784 struct fuse_write_in *inarg = &wpa->ia.write.in;
1785 struct fuse_writepage_args *next = wpa->next;
1786
1787 wpa->next = next->next;
1788 next->next = NULL;
1789 next->ia.ff = fuse_file_get(wpa->ia.ff);
1790 tree_insert(&fi->writepages, next);
1791
1792 /*
1793 * Skip fuse_flush_writepages() to make it easy to crop requests
1794 * based on primary request size.
1795 *
1796 * 1st case (trivial): there are no concurrent activities using
1797 * fuse_set/release_nowrite. Then we're on safe side because
1798 * fuse_flush_writepages() would call fuse_send_writepage()
1799 * anyway.
1800 *
1801 * 2nd case: someone called fuse_set_nowrite and it is waiting
1802 * now for completion of all in-flight requests. This happens
1803 * rarely and no more than once per page, so this should be
1804 * okay.
1805 *
1806 * 3rd case: someone (e.g. fuse_do_setattr()) is in the middle
1807 * of fuse_set_nowrite..fuse_release_nowrite section. The fact
1808 * that fuse_set_nowrite returned implies that all in-flight
1809 * requests were completed along with all of their secondary
1810 * requests. Further primary requests are blocked by negative
1811 * writectr. Hence there cannot be any in-flight requests and
1812 * no invocations of fuse_writepage_end() while we're in
1813 * fuse_set_nowrite..fuse_release_nowrite section.
1814 */
1815 fuse_send_writepage(fm, next, inarg->offset + inarg->size);
1816 }
1817 fi->writectr--;
1818 fuse_writepage_finish(fm, wpa);
1819 spin_unlock(&fi->lock);
1820 fuse_writepage_free(wpa);
1821 }
1822
1823 static struct fuse_file *__fuse_write_file_get(struct fuse_inode *fi)
1824 {
1825 struct fuse_file *ff = NULL;
1826
1827 spin_lock(&fi->lock);
1828 if (!list_empty(&fi->write_files)) {
1829 ff = list_entry(fi->write_files.next, struct fuse_file,
1830 write_entry);
1831 fuse_file_get(ff);
1832 }
1833 spin_unlock(&fi->lock);
1834
1835 return ff;
1836 }
1837
1838 static struct fuse_file *fuse_write_file_get(struct fuse_inode *fi)
1839 {
1840 struct fuse_file *ff = __fuse_write_file_get(fi);
1841 WARN_ON(!ff);
1842 return ff;
1843 }
1844
1845 int fuse_write_inode(struct inode *inode, struct writeback_control *wbc)
1846 {
1847 struct fuse_inode *fi = get_fuse_inode(inode);
1848 struct fuse_file *ff;
1849 int err;
1850
1851 ff = __fuse_write_file_get(fi);
1852 err = fuse_flush_times(inode, ff);
1853 if (ff)
1854 fuse_file_put(ff, false, false);
1855
1856 return err;
1857 }
1858
1859 static struct fuse_writepage_args *fuse_writepage_args_alloc(void)
1860 {
1861 struct fuse_writepage_args *wpa;
1862 struct fuse_args_pages *ap;
1863
1864 wpa = kzalloc(sizeof(*wpa), GFP_NOFS);
1865 if (wpa) {
1866 ap = &wpa->ia.ap;
1867 ap->num_pages = 0;
1868 ap->pages = fuse_pages_alloc(1, GFP_NOFS, &ap->descs);
1869 if (!ap->pages) {
1870 kfree(wpa);
1871 wpa = NULL;
1872 }
1873 }
1874 return wpa;
1875
1876 }
1877
1878 static void fuse_writepage_add_to_bucket(struct fuse_conn *fc,
1879 struct fuse_writepage_args *wpa)
1880 {
1881 if (!fc->sync_fs)
1882 return;
1883
1884 rcu_read_lock();
1885 /* Prevent resurrection of dead bucket in unlikely race with syncfs */
1886 do {
1887 wpa->bucket = rcu_dereference(fc->curr_bucket);
1888 } while (unlikely(!atomic_inc_not_zero(&wpa->bucket->count)));
1889 rcu_read_unlock();
1890 }
1891
1892 static int fuse_writepage_locked(struct page *page)
1893 {
1894 struct address_space *mapping = page->mapping;
1895 struct inode *inode = mapping->host;
1896 struct fuse_conn *fc = get_fuse_conn(inode);
1897 struct fuse_inode *fi = get_fuse_inode(inode);
1898 struct fuse_writepage_args *wpa;
1899 struct fuse_args_pages *ap;
1900 struct page *tmp_page;
1901 int error = -ENOMEM;
1902
1903 set_page_writeback(page);
1904
1905 wpa = fuse_writepage_args_alloc();
1906 if (!wpa)
1907 goto err;
1908 ap = &wpa->ia.ap;
1909
1910 tmp_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
1911 if (!tmp_page)
1912 goto err_free;
1913
1914 error = -EIO;
1915 wpa->ia.ff = fuse_write_file_get(fi);
1916 if (!wpa->ia.ff)
1917 goto err_nofile;
1918
1919 fuse_writepage_add_to_bucket(fc, wpa);
1920 fuse_write_args_fill(&wpa->ia, wpa->ia.ff, page_offset(page), 0);
1921
1922 copy_highpage(tmp_page, page);
1923 wpa->ia.write.in.write_flags |= FUSE_WRITE_CACHE;
1924 wpa->next = NULL;
1925 ap->args.in_pages = true;
1926 ap->num_pages = 1;
1927 ap->pages[0] = tmp_page;
1928 ap->descs[0].offset = 0;
1929 ap->descs[0].length = PAGE_SIZE;
1930 ap->args.end = fuse_writepage_end;
1931 wpa->inode = inode;
1932
1933 inc_wb_stat(&inode_to_bdi(inode)->wb, WB_WRITEBACK);
1934 inc_node_page_state(tmp_page, NR_WRITEBACK_TEMP);
1935
1936 spin_lock(&fi->lock);
1937 tree_insert(&fi->writepages, wpa);
1938 list_add_tail(&wpa->queue_entry, &fi->queued_writes);
1939 fuse_flush_writepages(inode);
1940 spin_unlock(&fi->lock);
1941
1942 end_page_writeback(page);
1943
1944 return 0;
1945
1946 err_nofile:
1947 __free_page(tmp_page);
1948 err_free:
1949 kfree(wpa);
1950 err:
1951 mapping_set_error(page->mapping, error);
1952 end_page_writeback(page);
1953 return error;
1954 }
1955
1956 static int fuse_writepage(struct page *page, struct writeback_control *wbc)
1957 {
1958 int err;
1959
1960 if (fuse_page_is_writeback(page->mapping->host, page->index)) {
1961 /*
1962 * ->writepages() should be called for sync() and friends. We
1963 * should only get here on direct reclaim and then we are
1964 * allowed to skip a page which is already in flight
1965 */
1966 WARN_ON(wbc->sync_mode == WB_SYNC_ALL);
1967
1968 redirty_page_for_writepage(wbc, page);
1969 unlock_page(page);
1970 return 0;
1971 }
1972
1973 err = fuse_writepage_locked(page);
1974 unlock_page(page);
1975
1976 return err;
1977 }
1978
1979 struct fuse_fill_wb_data {
1980 struct fuse_writepage_args *wpa;
1981 struct fuse_file *ff;
1982 struct inode *inode;
1983 struct page **orig_pages;
1984 unsigned int max_pages;
1985 };
1986
1987 static bool fuse_pages_realloc(struct fuse_fill_wb_data *data)
1988 {
1989 struct fuse_args_pages *ap = &data->wpa->ia.ap;
1990 struct fuse_conn *fc = get_fuse_conn(data->inode);
1991 struct page **pages;
1992 struct fuse_page_desc *descs;
1993 unsigned int npages = min_t(unsigned int,
1994 max_t(unsigned int, data->max_pages * 2,
1995 FUSE_DEFAULT_MAX_PAGES_PER_REQ),
1996 fc->max_pages);
1997 WARN_ON(npages <= data->max_pages);
1998
1999 pages = fuse_pages_alloc(npages, GFP_NOFS, &descs);
2000 if (!pages)
2001 return false;
2002
2003 memcpy(pages, ap->pages, sizeof(struct page *) * ap->num_pages);
2004 memcpy(descs, ap->descs, sizeof(struct fuse_page_desc) * ap->num_pages);
2005 kfree(ap->pages);
2006 ap->pages = pages;
2007 ap->descs = descs;
2008 data->max_pages = npages;
2009
2010 return true;
2011 }
2012
2013 static void fuse_writepages_send(struct fuse_fill_wb_data *data)
2014 {
2015 struct fuse_writepage_args *wpa = data->wpa;
2016 struct inode *inode = data->inode;
2017 struct fuse_inode *fi = get_fuse_inode(inode);
2018 int num_pages = wpa->ia.ap.num_pages;
2019 int i;
2020
2021 wpa->ia.ff = fuse_file_get(data->ff);
2022 spin_lock(&fi->lock);
2023 list_add_tail(&wpa->queue_entry, &fi->queued_writes);
2024 fuse_flush_writepages(inode);
2025 spin_unlock(&fi->lock);
2026
2027 for (i = 0; i < num_pages; i++)
2028 end_page_writeback(data->orig_pages[i]);
2029 }
2030
2031 /*
2032 * Check under fi->lock if the page is under writeback, and insert it onto the
2033 * rb_tree if not. Otherwise iterate auxiliary write requests, to see if there's
2034 * one already added for a page at this offset. If there's none, then insert
2035 * this new request onto the auxiliary list, otherwise reuse the existing one by
2036 * swapping the new temp page with the old one.
2037 */
2038 static bool fuse_writepage_add(struct fuse_writepage_args *new_wpa,
2039 struct page *page)
2040 {
2041 struct fuse_inode *fi = get_fuse_inode(new_wpa->inode);
2042 struct fuse_writepage_args *tmp;
2043 struct fuse_writepage_args *old_wpa;
2044 struct fuse_args_pages *new_ap = &new_wpa->ia.ap;
2045
2046 WARN_ON(new_ap->num_pages != 0);
2047 new_ap->num_pages = 1;
2048
2049 spin_lock(&fi->lock);
2050 old_wpa = fuse_insert_writeback(&fi->writepages, new_wpa);
2051 if (!old_wpa) {
2052 spin_unlock(&fi->lock);
2053 return true;
2054 }
2055
2056 for (tmp = old_wpa->next; tmp; tmp = tmp->next) {
2057 pgoff_t curr_index;
2058
2059 WARN_ON(tmp->inode != new_wpa->inode);
2060 curr_index = tmp->ia.write.in.offset >> PAGE_SHIFT;
2061 if (curr_index == page->index) {
2062 WARN_ON(tmp->ia.ap.num_pages != 1);
2063 swap(tmp->ia.ap.pages[0], new_ap->pages[0]);
2064 break;
2065 }
2066 }
2067
2068 if (!tmp) {
2069 new_wpa->next = old_wpa->next;
2070 old_wpa->next = new_wpa;
2071 }
2072
2073 spin_unlock(&fi->lock);
2074
2075 if (tmp) {
2076 struct backing_dev_info *bdi = inode_to_bdi(new_wpa->inode);
2077
2078 dec_wb_stat(&bdi->wb, WB_WRITEBACK);
2079 dec_node_page_state(new_ap->pages[0], NR_WRITEBACK_TEMP);
2080 wb_writeout_inc(&bdi->wb);
2081 fuse_writepage_free(new_wpa);
2082 }
2083
2084 return false;
2085 }
2086
2087 static bool fuse_writepage_need_send(struct fuse_conn *fc, struct page *page,
2088 struct fuse_args_pages *ap,
2089 struct fuse_fill_wb_data *data)
2090 {
2091 WARN_ON(!ap->num_pages);
2092
2093 /*
2094 * Being under writeback is unlikely but possible. For example direct
2095 * read to an mmaped fuse file will set the page dirty twice; once when
2096 * the pages are faulted with get_user_pages(), and then after the read
2097 * completed.
2098 */
2099 if (fuse_page_is_writeback(data->inode, page->index))
2100 return true;
2101
2102 /* Reached max pages */
2103 if (ap->num_pages == fc->max_pages)
2104 return true;
2105
2106 /* Reached max write bytes */
2107 if ((ap->num_pages + 1) * PAGE_SIZE > fc->max_write)
2108 return true;
2109
2110 /* Discontinuity */
2111 if (data->orig_pages[ap->num_pages - 1]->index + 1 != page->index)
2112 return true;
2113
2114 /* Need to grow the pages array? If so, did the expansion fail? */
2115 if (ap->num_pages == data->max_pages && !fuse_pages_realloc(data))
2116 return true;
2117
2118 return false;
2119 }
2120
2121 static int fuse_writepages_fill(struct page *page,
2122 struct writeback_control *wbc, void *_data)
2123 {
2124 struct fuse_fill_wb_data *data = _data;
2125 struct fuse_writepage_args *wpa = data->wpa;
2126 struct fuse_args_pages *ap = &wpa->ia.ap;
2127 struct inode *inode = data->inode;
2128 struct fuse_inode *fi = get_fuse_inode(inode);
2129 struct fuse_conn *fc = get_fuse_conn(inode);
2130 struct page *tmp_page;
2131 int err;
2132
2133 if (!data->ff) {
2134 err = -EIO;
2135 data->ff = fuse_write_file_get(fi);
2136 if (!data->ff)
2137 goto out_unlock;
2138 }
2139
2140 if (wpa && fuse_writepage_need_send(fc, page, ap, data)) {
2141 fuse_writepages_send(data);
2142 data->wpa = NULL;
2143 }
2144
2145 err = -ENOMEM;
2146 tmp_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
2147 if (!tmp_page)
2148 goto out_unlock;
2149
2150 /*
2151 * The page must not be redirtied until the writeout is completed
2152 * (i.e. userspace has sent a reply to the write request). Otherwise
2153 * there could be more than one temporary page instance for each real
2154 * page.
2155 *
2156 * This is ensured by holding the page lock in page_mkwrite() while
2157 * checking fuse_page_is_writeback(). We already hold the page lock
2158 * since clear_page_dirty_for_io() and keep it held until we add the
2159 * request to the fi->writepages list and increment ap->num_pages.
2160 * After this fuse_page_is_writeback() will indicate that the page is
2161 * under writeback, so we can release the page lock.
2162 */
2163 if (data->wpa == NULL) {
2164 err = -ENOMEM;
2165 wpa = fuse_writepage_args_alloc();
2166 if (!wpa) {
2167 __free_page(tmp_page);
2168 goto out_unlock;
2169 }
2170 fuse_writepage_add_to_bucket(fc, wpa);
2171
2172 data->max_pages = 1;
2173
2174 ap = &wpa->ia.ap;
2175 fuse_write_args_fill(&wpa->ia, data->ff, page_offset(page), 0);
2176 wpa->ia.write.in.write_flags |= FUSE_WRITE_CACHE;
2177 wpa->next = NULL;
2178 ap->args.in_pages = true;
2179 ap->args.end = fuse_writepage_end;
2180 ap->num_pages = 0;
2181 wpa->inode = inode;
2182 }
2183 set_page_writeback(page);
2184
2185 copy_highpage(tmp_page, page);
2186 ap->pages[ap->num_pages] = tmp_page;
2187 ap->descs[ap->num_pages].offset = 0;
2188 ap->descs[ap->num_pages].length = PAGE_SIZE;
2189 data->orig_pages[ap->num_pages] = page;
2190
2191 inc_wb_stat(&inode_to_bdi(inode)->wb, WB_WRITEBACK);
2192 inc_node_page_state(tmp_page, NR_WRITEBACK_TEMP);
2193
2194 err = 0;
2195 if (data->wpa) {
2196 /*
2197 * Protected by fi->lock against concurrent access by
2198 * fuse_page_is_writeback().
2199 */
2200 spin_lock(&fi->lock);
2201 ap->num_pages++;
2202 spin_unlock(&fi->lock);
2203 } else if (fuse_writepage_add(wpa, page)) {
2204 data->wpa = wpa;
2205 } else {
2206 end_page_writeback(page);
2207 }
2208 out_unlock:
2209 unlock_page(page);
2210
2211 return err;
2212 }
2213
2214 static int fuse_writepages(struct address_space *mapping,
2215 struct writeback_control *wbc)
2216 {
2217 struct inode *inode = mapping->host;
2218 struct fuse_conn *fc = get_fuse_conn(inode);
2219 struct fuse_fill_wb_data data;
2220 int err;
2221
2222 err = -EIO;
2223 if (fuse_is_bad(inode))
2224 goto out;
2225
2226 data.inode = inode;
2227 data.wpa = NULL;
2228 data.ff = NULL;
2229
2230 err = -ENOMEM;
2231 data.orig_pages = kcalloc(fc->max_pages,
2232 sizeof(struct page *),
2233 GFP_NOFS);
2234 if (!data.orig_pages)
2235 goto out;
2236
2237 err = write_cache_pages(mapping, wbc, fuse_writepages_fill, &data);
2238 if (data.wpa) {
2239 WARN_ON(!data.wpa->ia.ap.num_pages);
2240 fuse_writepages_send(&data);
2241 }
2242 if (data.ff)
2243 fuse_file_put(data.ff, false, false);
2244
2245 kfree(data.orig_pages);
2246 out:
2247 return err;
2248 }
2249
2250 /*
2251 * It's worthy to make sure that space is reserved on disk for the write,
2252 * but how to implement it without killing performance need more thinking.
2253 */
2254 static int fuse_write_begin(struct file *file, struct address_space *mapping,
2255 loff_t pos, unsigned len, unsigned flags,
2256 struct page **pagep, void **fsdata)
2257 {
2258 pgoff_t index = pos >> PAGE_SHIFT;
2259 struct fuse_conn *fc = get_fuse_conn(file_inode(file));
2260 struct page *page;
2261 loff_t fsize;
2262 int err = -ENOMEM;
2263
2264 WARN_ON(!fc->writeback_cache);
2265
2266 page = grab_cache_page_write_begin(mapping, index, flags);
2267 if (!page)
2268 goto error;
2269
2270 fuse_wait_on_page_writeback(mapping->host, page->index);
2271
2272 if (PageUptodate(page) || len == PAGE_SIZE)
2273 goto success;
2274 /*
2275 * Check if the start this page comes after the end of file, in which
2276 * case the readpage can be optimized away.
2277 */
2278 fsize = i_size_read(mapping->host);
2279 if (fsize <= (pos & PAGE_MASK)) {
2280 size_t off = pos & ~PAGE_MASK;
2281 if (off)
2282 zero_user_segment(page, 0, off);
2283 goto success;
2284 }
2285 err = fuse_do_readpage(file, page);
2286 if (err)
2287 goto cleanup;
2288 success:
2289 *pagep = page;
2290 return 0;
2291
2292 cleanup:
2293 unlock_page(page);
2294 put_page(page);
2295 error:
2296 return err;
2297 }
2298
2299 static int fuse_write_end(struct file *file, struct address_space *mapping,
2300 loff_t pos, unsigned len, unsigned copied,
2301 struct page *page, void *fsdata)
2302 {
2303 struct inode *inode = page->mapping->host;
2304
2305 /* Haven't copied anything? Skip zeroing, size extending, dirtying. */
2306 if (!copied)
2307 goto unlock;
2308
2309 if (!PageUptodate(page)) {
2310 /* Zero any unwritten bytes at the end of the page */
2311 size_t endoff = (pos + copied) & ~PAGE_MASK;
2312 if (endoff)
2313 zero_user_segment(page, endoff, PAGE_SIZE);
2314 SetPageUptodate(page);
2315 }
2316
2317 fuse_write_update_size(inode, pos + copied);
2318 set_page_dirty(page);
2319
2320 unlock:
2321 unlock_page(page);
2322 put_page(page);
2323
2324 return copied;
2325 }
2326
2327 static int fuse_launder_page(struct page *page)
2328 {
2329 int err = 0;
2330 if (clear_page_dirty_for_io(page)) {
2331 struct inode *inode = page->mapping->host;
2332
2333 /* Serialize with pending writeback for the same page */
2334 fuse_wait_on_page_writeback(inode, page->index);
2335 err = fuse_writepage_locked(page);
2336 if (!err)
2337 fuse_wait_on_page_writeback(inode, page->index);
2338 }
2339 return err;
2340 }
2341
2342 /*
2343 * Write back dirty pages now, because there may not be any suitable
2344 * open files later
2345 */
2346 static void fuse_vma_close(struct vm_area_struct *vma)
2347 {
2348 filemap_write_and_wait(vma->vm_file->f_mapping);
2349 }
2350
2351 /*
2352 * Wait for writeback against this page to complete before allowing it
2353 * to be marked dirty again, and hence written back again, possibly
2354 * before the previous writepage completed.
2355 *
2356 * Block here, instead of in ->writepage(), so that the userspace fs
2357 * can only block processes actually operating on the filesystem.
2358 *
2359 * Otherwise unprivileged userspace fs would be able to block
2360 * unrelated:
2361 *
2362 * - page migration
2363 * - sync(2)
2364 * - try_to_free_pages() with order > PAGE_ALLOC_COSTLY_ORDER
2365 */
2366 static vm_fault_t fuse_page_mkwrite(struct vm_fault *vmf)
2367 {
2368 struct page *page = vmf->page;
2369 struct inode *inode = file_inode(vmf->vma->vm_file);
2370
2371 file_update_time(vmf->vma->vm_file);
2372 lock_page(page);
2373 if (page->mapping != inode->i_mapping) {
2374 unlock_page(page);
2375 return VM_FAULT_NOPAGE;
2376 }
2377
2378 fuse_wait_on_page_writeback(inode, page->index);
2379 return VM_FAULT_LOCKED;
2380 }
2381
2382 static const struct vm_operations_struct fuse_file_vm_ops = {
2383 .close = fuse_vma_close,
2384 .fault = filemap_fault,
2385 .map_pages = filemap_map_pages,
2386 .page_mkwrite = fuse_page_mkwrite,
2387 };
2388
2389 static int fuse_file_mmap(struct file *file, struct vm_area_struct *vma)
2390 {
2391 struct fuse_file *ff = file->private_data;
2392
2393 /* DAX mmap is superior to direct_io mmap */
2394 if (FUSE_IS_DAX(file_inode(file)))
2395 return fuse_dax_mmap(file, vma);
2396
2397 if (ff->open_flags & FOPEN_DIRECT_IO) {
2398 /* Can't provide the coherency needed for MAP_SHARED */
2399 if (vma->vm_flags & VM_MAYSHARE)
2400 return -ENODEV;
2401
2402 invalidate_inode_pages2(file->f_mapping);
2403
2404 return generic_file_mmap(file, vma);
2405 }
2406
2407 if ((vma->vm_flags & VM_SHARED) && (vma->vm_flags & VM_MAYWRITE))
2408 fuse_link_write_file(file);
2409
2410 file_accessed(file);
2411 vma->vm_ops = &fuse_file_vm_ops;
2412 return 0;
2413 }
2414
2415 static int convert_fuse_file_lock(struct fuse_conn *fc,
2416 const struct fuse_file_lock *ffl,
2417 struct file_lock *fl)
2418 {
2419 switch (ffl->type) {
2420 case F_UNLCK:
2421 break;
2422
2423 case F_RDLCK:
2424 case F_WRLCK:
2425 if (ffl->start > OFFSET_MAX || ffl->end > OFFSET_MAX ||
2426 ffl->end < ffl->start)
2427 return -EIO;
2428
2429 fl->fl_start = ffl->start;
2430 fl->fl_end = ffl->end;
2431
2432 /*
2433 * Convert pid into init's pid namespace. The locks API will
2434 * translate it into the caller's pid namespace.
2435 */
2436 rcu_read_lock();
2437 fl->fl_pid = pid_nr_ns(find_pid_ns(ffl->pid, fc->pid_ns), &init_pid_ns);
2438 rcu_read_unlock();
2439 break;
2440
2441 default:
2442 return -EIO;
2443 }
2444 fl->fl_type = ffl->type;
2445 return 0;
2446 }
2447
2448 static void fuse_lk_fill(struct fuse_args *args, struct file *file,
2449 const struct file_lock *fl, int opcode, pid_t pid,
2450 int flock, struct fuse_lk_in *inarg)
2451 {
2452 struct inode *inode = file_inode(file);
2453 struct fuse_conn *fc = get_fuse_conn(inode);
2454 struct fuse_file *ff = file->private_data;
2455
2456 memset(inarg, 0, sizeof(*inarg));
2457 inarg->fh = ff->fh;
2458 inarg->owner = fuse_lock_owner_id(fc, fl->fl_owner);
2459 inarg->lk.start = fl->fl_start;
2460 inarg->lk.end = fl->fl_end;
2461 inarg->lk.type = fl->fl_type;
2462 inarg->lk.pid = pid;
2463 if (flock)
2464 inarg->lk_flags |= FUSE_LK_FLOCK;
2465 args->opcode = opcode;
2466 args->nodeid = get_node_id(inode);
2467 args->in_numargs = 1;
2468 args->in_args[0].size = sizeof(*inarg);
2469 args->in_args[0].value = inarg;
2470 }
2471
2472 static int fuse_getlk(struct file *file, struct file_lock *fl)
2473 {
2474 struct inode *inode = file_inode(file);
2475 struct fuse_mount *fm = get_fuse_mount(inode);
2476 FUSE_ARGS(args);
2477 struct fuse_lk_in inarg;
2478 struct fuse_lk_out outarg;
2479 int err;
2480
2481 fuse_lk_fill(&args, file, fl, FUSE_GETLK, 0, 0, &inarg);
2482 args.out_numargs = 1;
2483 args.out_args[0].size = sizeof(outarg);
2484 args.out_args[0].value = &outarg;
2485 err = fuse_simple_request(fm, &args);
2486 if (!err)
2487 err = convert_fuse_file_lock(fm->fc, &outarg.lk, fl);
2488
2489 return err;
2490 }
2491
2492 static int fuse_setlk(struct file *file, struct file_lock *fl, int flock)
2493 {
2494 struct inode *inode = file_inode(file);
2495 struct fuse_mount *fm = get_fuse_mount(inode);
2496 FUSE_ARGS(args);
2497 struct fuse_lk_in inarg;
2498 int opcode = (fl->fl_flags & FL_SLEEP) ? FUSE_SETLKW : FUSE_SETLK;
2499 struct pid *pid = fl->fl_type != F_UNLCK ? task_tgid(current) : NULL;
2500 pid_t pid_nr = pid_nr_ns(pid, fm->fc->pid_ns);
2501 int err;
2502
2503 if (fl->fl_lmops && fl->fl_lmops->lm_grant) {
2504 /* NLM needs asynchronous locks, which we don't support yet */
2505 return -ENOLCK;
2506 }
2507
2508 /* Unlock on close is handled by the flush method */
2509 if ((fl->fl_flags & FL_CLOSE_POSIX) == FL_CLOSE_POSIX)
2510 return 0;
2511
2512 fuse_lk_fill(&args, file, fl, opcode, pid_nr, flock, &inarg);
2513 err = fuse_simple_request(fm, &args);
2514
2515 /* locking is restartable */
2516 if (err == -EINTR)
2517 err = -ERESTARTSYS;
2518
2519 return err;
2520 }
2521
2522 static int fuse_file_lock(struct file *file, int cmd, struct file_lock *fl)
2523 {
2524 struct inode *inode = file_inode(file);
2525 struct fuse_conn *fc = get_fuse_conn(inode);
2526 int err;
2527
2528 if (cmd == F_CANCELLK) {
2529 err = 0;
2530 } else if (cmd == F_GETLK) {
2531 if (fc->no_lock) {
2532 posix_test_lock(file, fl);
2533 err = 0;
2534 } else
2535 err = fuse_getlk(file, fl);
2536 } else {
2537 if (fc->no_lock)
2538 err = posix_lock_file(file, fl, NULL);
2539 else
2540 err = fuse_setlk(file, fl, 0);
2541 }
2542 return err;
2543 }
2544
2545 static int fuse_file_flock(struct file *file, int cmd, struct file_lock *fl)
2546 {
2547 struct inode *inode = file_inode(file);
2548 struct fuse_conn *fc = get_fuse_conn(inode);
2549 int err;
2550
2551 if (fc->no_flock) {
2552 err = locks_lock_file_wait(file, fl);
2553 } else {
2554 struct fuse_file *ff = file->private_data;
2555
2556 /* emulate flock with POSIX locks */
2557 ff->flock = true;
2558 err = fuse_setlk(file, fl, 1);
2559 }
2560
2561 return err;
2562 }
2563
2564 static sector_t fuse_bmap(struct address_space *mapping, sector_t block)
2565 {
2566 struct inode *inode = mapping->host;
2567 struct fuse_mount *fm = get_fuse_mount(inode);
2568 FUSE_ARGS(args);
2569 struct fuse_bmap_in inarg;
2570 struct fuse_bmap_out outarg;
2571 int err;
2572
2573 if (!inode->i_sb->s_bdev || fm->fc->no_bmap)
2574 return 0;
2575
2576 memset(&inarg, 0, sizeof(inarg));
2577 inarg.block = block;
2578 inarg.blocksize = inode->i_sb->s_blocksize;
2579 args.opcode = FUSE_BMAP;
2580 args.nodeid = get_node_id(inode);
2581 args.in_numargs = 1;
2582 args.in_args[0].size = sizeof(inarg);
2583 args.in_args[0].value = &inarg;
2584 args.out_numargs = 1;
2585 args.out_args[0].size = sizeof(outarg);
2586 args.out_args[0].value = &outarg;
2587 err = fuse_simple_request(fm, &args);
2588 if (err == -ENOSYS)
2589 fm->fc->no_bmap = 1;
2590
2591 return err ? 0 : outarg.block;
2592 }
2593
2594 static loff_t fuse_lseek(struct file *file, loff_t offset, int whence)
2595 {
2596 struct inode *inode = file->f_mapping->host;
2597 struct fuse_mount *fm = get_fuse_mount(inode);
2598 struct fuse_file *ff = file->private_data;
2599 FUSE_ARGS(args);
2600 struct fuse_lseek_in inarg = {
2601 .fh = ff->fh,
2602 .offset = offset,
2603 .whence = whence
2604 };
2605 struct fuse_lseek_out outarg;
2606 int err;
2607
2608 if (fm->fc->no_lseek)
2609 goto fallback;
2610
2611 args.opcode = FUSE_LSEEK;
2612 args.nodeid = ff->nodeid;
2613 args.in_numargs = 1;
2614 args.in_args[0].size = sizeof(inarg);
2615 args.in_args[0].value = &inarg;
2616 args.out_numargs = 1;
2617 args.out_args[0].size = sizeof(outarg);
2618 args.out_args[0].value = &outarg;
2619 err = fuse_simple_request(fm, &args);
2620 if (err) {
2621 if (err == -ENOSYS) {
2622 fm->fc->no_lseek = 1;
2623 goto fallback;
2624 }
2625 return err;
2626 }
2627
2628 return vfs_setpos(file, outarg.offset, inode->i_sb->s_maxbytes);
2629
2630 fallback:
2631 err = fuse_update_attributes(inode, file);
2632 if (!err)
2633 return generic_file_llseek(file, offset, whence);
2634 else
2635 return err;
2636 }
2637
2638 static loff_t fuse_file_llseek(struct file *file, loff_t offset, int whence)
2639 {
2640 loff_t retval;
2641 struct inode *inode = file_inode(file);
2642
2643 switch (whence) {
2644 case SEEK_SET:
2645 case SEEK_CUR:
2646 /* No i_mutex protection necessary for SEEK_CUR and SEEK_SET */
2647 retval = generic_file_llseek(file, offset, whence);
2648 break;
2649 case SEEK_END:
2650 inode_lock(inode);
2651 retval = fuse_update_attributes(inode, file);
2652 if (!retval)
2653 retval = generic_file_llseek(file, offset, whence);
2654 inode_unlock(inode);
2655 break;
2656 case SEEK_HOLE:
2657 case SEEK_DATA:
2658 inode_lock(inode);
2659 retval = fuse_lseek(file, offset, whence);
2660 inode_unlock(inode);
2661 break;
2662 default:
2663 retval = -EINVAL;
2664 }
2665
2666 return retval;
2667 }
2668
2669 /*
2670 * All files which have been polled are linked to RB tree
2671 * fuse_conn->polled_files which is indexed by kh. Walk the tree and
2672 * find the matching one.
2673 */
2674 static struct rb_node **fuse_find_polled_node(struct fuse_conn *fc, u64 kh,
2675 struct rb_node **parent_out)
2676 {
2677 struct rb_node **link = &fc->polled_files.rb_node;
2678 struct rb_node *last = NULL;
2679
2680 while (*link) {
2681 struct fuse_file *ff;
2682
2683 last = *link;
2684 ff = rb_entry(last, struct fuse_file, polled_node);
2685
2686 if (kh < ff->kh)
2687 link = &last->rb_left;
2688 else if (kh > ff->kh)
2689 link = &last->rb_right;
2690 else
2691 return link;
2692 }
2693
2694 if (parent_out)
2695 *parent_out = last;
2696 return link;
2697 }
2698
2699 /*
2700 * The file is about to be polled. Make sure it's on the polled_files
2701 * RB tree. Note that files once added to the polled_files tree are
2702 * not removed before the file is released. This is because a file
2703 * polled once is likely to be polled again.
2704 */
2705 static void fuse_register_polled_file(struct fuse_conn *fc,
2706 struct fuse_file *ff)
2707 {
2708 spin_lock(&fc->lock);
2709 if (RB_EMPTY_NODE(&ff->polled_node)) {
2710 struct rb_node **link, *parent;
2711
2712 link = fuse_find_polled_node(fc, ff->kh, &parent);
2713 BUG_ON(*link);
2714 rb_link_node(&ff->polled_node, parent, link);
2715 rb_insert_color(&ff->polled_node, &fc->polled_files);
2716 }
2717 spin_unlock(&fc->lock);
2718 }
2719
2720 __poll_t fuse_file_poll(struct file *file, poll_table *wait)
2721 {
2722 struct fuse_file *ff = file->private_data;
2723 struct fuse_mount *fm = ff->fm;
2724 struct fuse_poll_in inarg = { .fh = ff->fh, .kh = ff->kh };
2725 struct fuse_poll_out outarg;
2726 FUSE_ARGS(args);
2727 int err;
2728
2729 if (fm->fc->no_poll)
2730 return DEFAULT_POLLMASK;
2731
2732 poll_wait(file, &ff->poll_wait, wait);
2733 inarg.events = mangle_poll(poll_requested_events(wait));
2734
2735 /*
2736 * Ask for notification iff there's someone waiting for it.
2737 * The client may ignore the flag and always notify.
2738 */
2739 if (waitqueue_active(&ff->poll_wait)) {
2740 inarg.flags |= FUSE_POLL_SCHEDULE_NOTIFY;
2741 fuse_register_polled_file(fm->fc, ff);
2742 }
2743
2744 args.opcode = FUSE_POLL;
2745 args.nodeid = ff->nodeid;
2746 args.in_numargs = 1;
2747 args.in_args[0].size = sizeof(inarg);
2748 args.in_args[0].value = &inarg;
2749 args.out_numargs = 1;
2750 args.out_args[0].size = sizeof(outarg);
2751 args.out_args[0].value = &outarg;
2752 err = fuse_simple_request(fm, &args);
2753
2754 if (!err)
2755 return demangle_poll(outarg.revents);
2756 if (err == -ENOSYS) {
2757 fm->fc->no_poll = 1;
2758 return DEFAULT_POLLMASK;
2759 }
2760 return EPOLLERR;
2761 }
2762 EXPORT_SYMBOL_GPL(fuse_file_poll);
2763
2764 /*
2765 * This is called from fuse_handle_notify() on FUSE_NOTIFY_POLL and
2766 * wakes up the poll waiters.
2767 */
2768 int fuse_notify_poll_wakeup(struct fuse_conn *fc,
2769 struct fuse_notify_poll_wakeup_out *outarg)
2770 {
2771 u64 kh = outarg->kh;
2772 struct rb_node **link;
2773
2774 spin_lock(&fc->lock);
2775
2776 link = fuse_find_polled_node(fc, kh, NULL);
2777 if (*link) {
2778 struct fuse_file *ff;
2779
2780 ff = rb_entry(*link, struct fuse_file, polled_node);
2781 wake_up_interruptible_sync(&ff->poll_wait);
2782 }
2783
2784 spin_unlock(&fc->lock);
2785 return 0;
2786 }
2787
2788 static void fuse_do_truncate(struct file *file)
2789 {
2790 struct inode *inode = file->f_mapping->host;
2791 struct iattr attr;
2792
2793 attr.ia_valid = ATTR_SIZE;
2794 attr.ia_size = i_size_read(inode);
2795
2796 attr.ia_file = file;
2797 attr.ia_valid |= ATTR_FILE;
2798
2799 fuse_do_setattr(file_dentry(file), &attr, file);
2800 }
2801
2802 static inline loff_t fuse_round_up(struct fuse_conn *fc, loff_t off)
2803 {
2804 return round_up(off, fc->max_pages << PAGE_SHIFT);
2805 }
2806
2807 static ssize_t
2808 fuse_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
2809 {
2810 DECLARE_COMPLETION_ONSTACK(wait);
2811 ssize_t ret = 0;
2812 struct file *file = iocb->ki_filp;
2813 struct fuse_file *ff = file->private_data;
2814 loff_t pos = 0;
2815 struct inode *inode;
2816 loff_t i_size;
2817 size_t count = iov_iter_count(iter), shortened = 0;
2818 loff_t offset = iocb->ki_pos;
2819 struct fuse_io_priv *io;
2820
2821 pos = offset;
2822 inode = file->f_mapping->host;
2823 i_size = i_size_read(inode);
2824
2825 if ((iov_iter_rw(iter) == READ) && (offset >= i_size))
2826 return 0;
2827
2828 io = kmalloc(sizeof(struct fuse_io_priv), GFP_KERNEL);
2829 if (!io)
2830 return -ENOMEM;
2831 spin_lock_init(&io->lock);
2832 kref_init(&io->refcnt);
2833 io->reqs = 1;
2834 io->bytes = -1;
2835 io->size = 0;
2836 io->offset = offset;
2837 io->write = (iov_iter_rw(iter) == WRITE);
2838 io->err = 0;
2839 /*
2840 * By default, we want to optimize all I/Os with async request
2841 * submission to the client filesystem if supported.
2842 */
2843 io->async = ff->fm->fc->async_dio;
2844 io->iocb = iocb;
2845 io->blocking = is_sync_kiocb(iocb);
2846
2847 /* optimization for short read */
2848 if (io->async && !io->write && offset + count > i_size) {
2849 iov_iter_truncate(iter, fuse_round_up(ff->fm->fc, i_size - offset));
2850 shortened = count - iov_iter_count(iter);
2851 count -= shortened;
2852 }
2853
2854 /*
2855 * We cannot asynchronously extend the size of a file.
2856 * In such case the aio will behave exactly like sync io.
2857 */
2858 if ((offset + count > i_size) && io->write)
2859 io->blocking = true;
2860
2861 if (io->async && io->blocking) {
2862 /*
2863 * Additional reference to keep io around after
2864 * calling fuse_aio_complete()
2865 */
2866 kref_get(&io->refcnt);
2867 io->done = &wait;
2868 }
2869
2870 if (iov_iter_rw(iter) == WRITE) {
2871 ret = fuse_direct_io(io, iter, &pos, FUSE_DIO_WRITE);
2872 fuse_invalidate_attr(inode);
2873 } else {
2874 ret = __fuse_direct_read(io, iter, &pos);
2875 }
2876 iov_iter_reexpand(iter, iov_iter_count(iter) + shortened);
2877
2878 if (io->async) {
2879 bool blocking = io->blocking;
2880
2881 fuse_aio_complete(io, ret < 0 ? ret : 0, -1);
2882
2883 /* we have a non-extending, async request, so return */
2884 if (!blocking)
2885 return -EIOCBQUEUED;
2886
2887 wait_for_completion(&wait);
2888 ret = fuse_get_res_by_io(io);
2889 }
2890
2891 kref_put(&io->refcnt, fuse_io_release);
2892
2893 if (iov_iter_rw(iter) == WRITE) {
2894 if (ret > 0)
2895 fuse_write_update_size(inode, pos);
2896 else if (ret < 0 && offset + count > i_size)
2897 fuse_do_truncate(file);
2898 }
2899
2900 return ret;
2901 }
2902
2903 static int fuse_writeback_range(struct inode *inode, loff_t start, loff_t end)
2904 {
2905 int err = filemap_write_and_wait_range(inode->i_mapping, start, -1);
2906
2907 if (!err)
2908 fuse_sync_writes(inode);
2909
2910 return err;
2911 }
2912
2913 static long fuse_file_fallocate(struct file *file, int mode, loff_t offset,
2914 loff_t length)
2915 {
2916 struct fuse_file *ff = file->private_data;
2917 struct inode *inode = file_inode(file);
2918 struct fuse_inode *fi = get_fuse_inode(inode);
2919 struct fuse_mount *fm = ff->fm;
2920 FUSE_ARGS(args);
2921 struct fuse_fallocate_in inarg = {
2922 .fh = ff->fh,
2923 .offset = offset,
2924 .length = length,
2925 .mode = mode
2926 };
2927 int err;
2928 bool lock_inode = !(mode & FALLOC_FL_KEEP_SIZE) ||
2929 (mode & (FALLOC_FL_PUNCH_HOLE |
2930 FALLOC_FL_ZERO_RANGE));
2931
2932 bool block_faults = FUSE_IS_DAX(inode) && lock_inode;
2933
2934 if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE |
2935 FALLOC_FL_ZERO_RANGE))
2936 return -EOPNOTSUPP;
2937
2938 if (fm->fc->no_fallocate)
2939 return -EOPNOTSUPP;
2940
2941 if (lock_inode) {
2942 inode_lock(inode);
2943 if (block_faults) {
2944 filemap_invalidate_lock(inode->i_mapping);
2945 err = fuse_dax_break_layouts(inode, 0, 0);
2946 if (err)
2947 goto out;
2948 }
2949
2950 if (mode & (FALLOC_FL_PUNCH_HOLE | FALLOC_FL_ZERO_RANGE)) {
2951 loff_t endbyte = offset + length - 1;
2952
2953 err = fuse_writeback_range(inode, offset, endbyte);
2954 if (err)
2955 goto out;
2956 }
2957 }
2958
2959 if (!(mode & FALLOC_FL_KEEP_SIZE) &&
2960 offset + length > i_size_read(inode)) {
2961 err = inode_newsize_ok(inode, offset + length);
2962 if (err)
2963 goto out;
2964 }
2965
2966 if (!(mode & FALLOC_FL_KEEP_SIZE))
2967 set_bit(FUSE_I_SIZE_UNSTABLE, &fi->state);
2968
2969 args.opcode = FUSE_FALLOCATE;
2970 args.nodeid = ff->nodeid;
2971 args.in_numargs = 1;
2972 args.in_args[0].size = sizeof(inarg);
2973 args.in_args[0].value = &inarg;
2974 err = fuse_simple_request(fm, &args);
2975 if (err == -ENOSYS) {
2976 fm->fc->no_fallocate = 1;
2977 err = -EOPNOTSUPP;
2978 }
2979 if (err)
2980 goto out;
2981
2982 /* we could have extended the file */
2983 if (!(mode & FALLOC_FL_KEEP_SIZE)) {
2984 bool changed = fuse_write_update_size(inode, offset + length);
2985
2986 if (changed && fm->fc->writeback_cache)
2987 file_update_time(file);
2988 }
2989
2990 if (mode & (FALLOC_FL_PUNCH_HOLE | FALLOC_FL_ZERO_RANGE))
2991 truncate_pagecache_range(inode, offset, offset + length - 1);
2992
2993 fuse_invalidate_attr(inode);
2994
2995 out:
2996 if (!(mode & FALLOC_FL_KEEP_SIZE))
2997 clear_bit(FUSE_I_SIZE_UNSTABLE, &fi->state);
2998
2999 if (block_faults)
3000 filemap_invalidate_unlock(inode->i_mapping);
3001
3002 if (lock_inode)
3003 inode_unlock(inode);
3004
3005 return err;
3006 }
3007
3008 static ssize_t __fuse_copy_file_range(struct file *file_in, loff_t pos_in,
3009 struct file *file_out, loff_t pos_out,
3010 size_t len, unsigned int flags)
3011 {
3012 struct fuse_file *ff_in = file_in->private_data;
3013 struct fuse_file *ff_out = file_out->private_data;
3014 struct inode *inode_in = file_inode(file_in);
3015 struct inode *inode_out = file_inode(file_out);
3016 struct fuse_inode *fi_out = get_fuse_inode(inode_out);
3017 struct fuse_mount *fm = ff_in->fm;
3018 struct fuse_conn *fc = fm->fc;
3019 FUSE_ARGS(args);
3020 struct fuse_copy_file_range_in inarg = {
3021 .fh_in = ff_in->fh,
3022 .off_in = pos_in,
3023 .nodeid_out = ff_out->nodeid,
3024 .fh_out = ff_out->fh,
3025 .off_out = pos_out,
3026 .len = len,
3027 .flags = flags
3028 };
3029 struct fuse_write_out outarg;
3030 ssize_t err;
3031 /* mark unstable when write-back is not used, and file_out gets
3032 * extended */
3033 bool is_unstable = (!fc->writeback_cache) &&
3034 ((pos_out + len) > inode_out->i_size);
3035
3036 if (fc->no_copy_file_range)
3037 return -EOPNOTSUPP;
3038
3039 if (file_inode(file_in)->i_sb != file_inode(file_out)->i_sb)
3040 return -EXDEV;
3041
3042 inode_lock(inode_in);
3043 err = fuse_writeback_range(inode_in, pos_in, pos_in + len - 1);
3044 inode_unlock(inode_in);
3045 if (err)
3046 return err;
3047
3048 inode_lock(inode_out);
3049
3050 err = file_modified(file_out);
3051 if (err)
3052 goto out;
3053
3054 /*
3055 * Write out dirty pages in the destination file before sending the COPY
3056 * request to userspace. After the request is completed, truncate off
3057 * pages (including partial ones) from the cache that have been copied,
3058 * since these contain stale data at that point.
3059 *
3060 * This should be mostly correct, but if the COPY writes to partial
3061 * pages (at the start or end) and the parts not covered by the COPY are
3062 * written through a memory map after calling fuse_writeback_range(),
3063 * then these partial page modifications will be lost on truncation.
3064 *
3065 * It is unlikely that someone would rely on such mixed style
3066 * modifications. Yet this does give less guarantees than if the
3067 * copying was performed with write(2).
3068 *
3069 * To fix this a mapping->invalidate_lock could be used to prevent new
3070 * faults while the copy is ongoing.
3071 */
3072 err = fuse_writeback_range(inode_out, pos_out, pos_out + len - 1);
3073 if (err)
3074 goto out;
3075
3076 if (is_unstable)
3077 set_bit(FUSE_I_SIZE_UNSTABLE, &fi_out->state);
3078
3079 args.opcode = FUSE_COPY_FILE_RANGE;
3080 args.nodeid = ff_in->nodeid;
3081 args.in_numargs = 1;
3082 args.in_args[0].size = sizeof(inarg);
3083 args.in_args[0].value = &inarg;
3084 args.out_numargs = 1;
3085 args.out_args[0].size = sizeof(outarg);
3086 args.out_args[0].value = &outarg;
3087 err = fuse_simple_request(fm, &args);
3088 if (err == -ENOSYS) {
3089 fc->no_copy_file_range = 1;
3090 err = -EOPNOTSUPP;
3091 }
3092 if (err)
3093 goto out;
3094
3095 truncate_inode_pages_range(inode_out->i_mapping,
3096 ALIGN_DOWN(pos_out, PAGE_SIZE),
3097 ALIGN(pos_out + outarg.size, PAGE_SIZE) - 1);
3098
3099 if (fc->writeback_cache) {
3100 fuse_write_update_size(inode_out, pos_out + outarg.size);
3101 file_update_time(file_out);
3102 }
3103
3104 fuse_invalidate_attr(inode_out);
3105
3106 err = outarg.size;
3107 out:
3108 if (is_unstable)
3109 clear_bit(FUSE_I_SIZE_UNSTABLE, &fi_out->state);
3110
3111 inode_unlock(inode_out);
3112 file_accessed(file_in);
3113
3114 return err;
3115 }
3116
3117 static ssize_t fuse_copy_file_range(struct file *src_file, loff_t src_off,
3118 struct file *dst_file, loff_t dst_off,
3119 size_t len, unsigned int flags)
3120 {
3121 ssize_t ret;
3122
3123 ret = __fuse_copy_file_range(src_file, src_off, dst_file, dst_off,
3124 len, flags);
3125
3126 if (ret == -EOPNOTSUPP || ret == -EXDEV)
3127 ret = generic_copy_file_range(src_file, src_off, dst_file,
3128 dst_off, len, flags);
3129 return ret;
3130 }
3131
3132 static const struct file_operations fuse_file_operations = {
3133 .llseek = fuse_file_llseek,
3134 .read_iter = fuse_file_read_iter,
3135 .write_iter = fuse_file_write_iter,
3136 .mmap = fuse_file_mmap,
3137 .open = fuse_open,
3138 .flush = fuse_flush,
3139 .release = fuse_release,
3140 .fsync = fuse_fsync,
3141 .lock = fuse_file_lock,
3142 .get_unmapped_area = thp_get_unmapped_area,
3143 .flock = fuse_file_flock,
3144 .splice_read = generic_file_splice_read,
3145 .splice_write = iter_file_splice_write,
3146 .unlocked_ioctl = fuse_file_ioctl,
3147 .compat_ioctl = fuse_file_compat_ioctl,
3148 .poll = fuse_file_poll,
3149 .fallocate = fuse_file_fallocate,
3150 .copy_file_range = fuse_copy_file_range,
3151 };
3152
3153 static const struct address_space_operations fuse_file_aops = {
3154 .readpage = fuse_readpage,
3155 .readahead = fuse_readahead,
3156 .writepage = fuse_writepage,
3157 .writepages = fuse_writepages,
3158 .launder_page = fuse_launder_page,
3159 .set_page_dirty = __set_page_dirty_nobuffers,
3160 .bmap = fuse_bmap,
3161 .direct_IO = fuse_direct_IO,
3162 .write_begin = fuse_write_begin,
3163 .write_end = fuse_write_end,
3164 };
3165
3166 void fuse_init_file_inode(struct inode *inode)
3167 {
3168 struct fuse_inode *fi = get_fuse_inode(inode);
3169
3170 inode->i_fop = &fuse_file_operations;
3171 inode->i_data.a_ops = &fuse_file_aops;
3172
3173 INIT_LIST_HEAD(&fi->write_files);
3174 INIT_LIST_HEAD(&fi->queued_writes);
3175 fi->writectr = 0;
3176 init_waitqueue_head(&fi->page_waitq);
3177 fi->writepages = RB_ROOT;
3178
3179 if (IS_ENABLED(CONFIG_FUSE_DAX))
3180 fuse_dax_inode_init(inode);
3181 }
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