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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
22static 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
51struct fuse_release_args {
52 struct fuse_args args;
53 struct fuse_release_in inarg;
54 struct inode *inode;
55};
56
57struct 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
84void fuse_file_free(struct fuse_file *ff)
85{
86 kfree(ff->release_args);
87 mutex_destroy(&ff->readdir.lock);
88 kfree(ff);
89}
90
91static struct fuse_file *fuse_file_get(struct fuse_file *ff)
92{
93 refcount_inc(&ff->count);
94 return ff;
95}
96
97static 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
106static 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
127struct 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
169int 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}
179EXPORT_SYMBOL_GPL(fuse_do_open);
180
181static 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
196void 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 file_update_time(file);
214 fuse_invalidate_attr_mask(inode, FUSE_STATX_MODSIZE);
215 }
216 if ((file->f_mode & FMODE_WRITE) && fc->writeback_cache)
217 fuse_link_write_file(file);
218}
219
220int fuse_open_common(struct inode *inode, struct file *file, bool isdir)
221{
222 struct fuse_mount *fm = get_fuse_mount(inode);
223 struct fuse_conn *fc = fm->fc;
224 int err;
225 bool is_wb_truncate = (file->f_flags & O_TRUNC) &&
226 fc->atomic_o_trunc &&
227 fc->writeback_cache;
228 bool dax_truncate = (file->f_flags & O_TRUNC) &&
229 fc->atomic_o_trunc && FUSE_IS_DAX(inode);
230
231 if (fuse_is_bad(inode))
232 return -EIO;
233
234 err = generic_file_open(inode, file);
235 if (err)
236 return err;
237
238 if (is_wb_truncate || dax_truncate)
239 inode_lock(inode);
240
241 if (dax_truncate) {
242 filemap_invalidate_lock(inode->i_mapping);
243 err = fuse_dax_break_layouts(inode, 0, 0);
244 if (err)
245 goto out_inode_unlock;
246 }
247
248 if (is_wb_truncate || dax_truncate)
249 fuse_set_nowrite(inode);
250
251 err = fuse_do_open(fm, get_node_id(inode), file, isdir);
252 if (!err)
253 fuse_finish_open(inode, file);
254
255 if (is_wb_truncate || dax_truncate)
256 fuse_release_nowrite(inode);
257 if (!err) {
258 struct fuse_file *ff = file->private_data;
259
260 if (fc->atomic_o_trunc && (file->f_flags & O_TRUNC))
261 truncate_pagecache(inode, 0);
262 else if (!(ff->open_flags & FOPEN_KEEP_CACHE))
263 invalidate_inode_pages2(inode->i_mapping);
264 }
265 if (dax_truncate)
266 filemap_invalidate_unlock(inode->i_mapping);
267out_inode_unlock:
268 if (is_wb_truncate || dax_truncate)
269 inode_unlock(inode);
270
271 return err;
272}
273
274static void fuse_prepare_release(struct fuse_inode *fi, struct fuse_file *ff,
275 unsigned int flags, int opcode)
276{
277 struct fuse_conn *fc = ff->fm->fc;
278 struct fuse_release_args *ra = ff->release_args;
279
280 /* Inode is NULL on error path of fuse_create_open() */
281 if (likely(fi)) {
282 spin_lock(&fi->lock);
283 list_del(&ff->write_entry);
284 spin_unlock(&fi->lock);
285 }
286 spin_lock(&fc->lock);
287 if (!RB_EMPTY_NODE(&ff->polled_node))
288 rb_erase(&ff->polled_node, &fc->polled_files);
289 spin_unlock(&fc->lock);
290
291 wake_up_interruptible_all(&ff->poll_wait);
292
293 ra->inarg.fh = ff->fh;
294 ra->inarg.flags = flags;
295 ra->args.in_numargs = 1;
296 ra->args.in_args[0].size = sizeof(struct fuse_release_in);
297 ra->args.in_args[0].value = &ra->inarg;
298 ra->args.opcode = opcode;
299 ra->args.nodeid = ff->nodeid;
300 ra->args.force = true;
301 ra->args.nocreds = true;
302}
303
304void fuse_file_release(struct inode *inode, struct fuse_file *ff,
305 unsigned int open_flags, fl_owner_t id, bool isdir)
306{
307 struct fuse_inode *fi = get_fuse_inode(inode);
308 struct fuse_release_args *ra = ff->release_args;
309 int opcode = isdir ? FUSE_RELEASEDIR : FUSE_RELEASE;
310
311 fuse_prepare_release(fi, ff, open_flags, opcode);
312
313 if (ff->flock) {
314 ra->inarg.release_flags |= FUSE_RELEASE_FLOCK_UNLOCK;
315 ra->inarg.lock_owner = fuse_lock_owner_id(ff->fm->fc, id);
316 }
317 /* Hold inode until release is finished */
318 ra->inode = igrab(inode);
319
320 /*
321 * Normally this will send the RELEASE request, however if
322 * some asynchronous READ or WRITE requests are outstanding,
323 * the sending will be delayed.
324 *
325 * Make the release synchronous if this is a fuseblk mount,
326 * synchronous RELEASE is allowed (and desirable) in this case
327 * because the server can be trusted not to screw up.
328 */
329 fuse_file_put(ff, ff->fm->fc->destroy, isdir);
330}
331
332void fuse_release_common(struct file *file, bool isdir)
333{
334 fuse_file_release(file_inode(file), file->private_data, file->f_flags,
335 (fl_owner_t) file, isdir);
336}
337
338static int fuse_open(struct inode *inode, struct file *file)
339{
340 return fuse_open_common(inode, file, false);
341}
342
343static int fuse_release(struct inode *inode, struct file *file)
344{
345 struct fuse_conn *fc = get_fuse_conn(inode);
346
347 /*
348 * Dirty pages might remain despite write_inode_now() call from
349 * fuse_flush() due to writes racing with the close.
350 */
351 if (fc->writeback_cache)
352 write_inode_now(inode, 1);
353
354 fuse_release_common(file, false);
355
356 /* return value is ignored by VFS */
357 return 0;
358}
359
360void fuse_sync_release(struct fuse_inode *fi, struct fuse_file *ff,
361 unsigned int flags)
362{
363 WARN_ON(refcount_read(&ff->count) > 1);
364 fuse_prepare_release(fi, ff, flags, FUSE_RELEASE);
365 /*
366 * iput(NULL) is a no-op and since the refcount is 1 and everything's
367 * synchronous, we are fine with not doing igrab() here"
368 */
369 fuse_file_put(ff, true, false);
370}
371EXPORT_SYMBOL_GPL(fuse_sync_release);
372
373/*
374 * Scramble the ID space with XTEA, so that the value of the files_struct
375 * pointer is not exposed to userspace.
376 */
377u64 fuse_lock_owner_id(struct fuse_conn *fc, fl_owner_t id)
378{
379 u32 *k = fc->scramble_key;
380 u64 v = (unsigned long) id;
381 u32 v0 = v;
382 u32 v1 = v >> 32;
383 u32 sum = 0;
384 int i;
385
386 for (i = 0; i < 32; i++) {
387 v0 += ((v1 << 4 ^ v1 >> 5) + v1) ^ (sum + k[sum & 3]);
388 sum += 0x9E3779B9;
389 v1 += ((v0 << 4 ^ v0 >> 5) + v0) ^ (sum + k[sum>>11 & 3]);
390 }
391
392 return (u64) v0 + ((u64) v1 << 32);
393}
394
395struct fuse_writepage_args {
396 struct fuse_io_args ia;
397 struct rb_node writepages_entry;
398 struct list_head queue_entry;
399 struct fuse_writepage_args *next;
400 struct inode *inode;
401 struct fuse_sync_bucket *bucket;
402};
403
404static struct fuse_writepage_args *fuse_find_writeback(struct fuse_inode *fi,
405 pgoff_t idx_from, pgoff_t idx_to)
406{
407 struct rb_node *n;
408
409 n = fi->writepages.rb_node;
410
411 while (n) {
412 struct fuse_writepage_args *wpa;
413 pgoff_t curr_index;
414
415 wpa = rb_entry(n, struct fuse_writepage_args, writepages_entry);
416 WARN_ON(get_fuse_inode(wpa->inode) != fi);
417 curr_index = wpa->ia.write.in.offset >> PAGE_SHIFT;
418 if (idx_from >= curr_index + wpa->ia.ap.num_pages)
419 n = n->rb_right;
420 else if (idx_to < curr_index)
421 n = n->rb_left;
422 else
423 return wpa;
424 }
425 return NULL;
426}
427
428/*
429 * Check if any page in a range is under writeback
430 *
431 * This is currently done by walking the list of writepage requests
432 * for the inode, which can be pretty inefficient.
433 */
434static bool fuse_range_is_writeback(struct inode *inode, pgoff_t idx_from,
435 pgoff_t idx_to)
436{
437 struct fuse_inode *fi = get_fuse_inode(inode);
438 bool found;
439
440 spin_lock(&fi->lock);
441 found = fuse_find_writeback(fi, idx_from, idx_to);
442 spin_unlock(&fi->lock);
443
444 return found;
445}
446
447static inline bool fuse_page_is_writeback(struct inode *inode, pgoff_t index)
448{
449 return fuse_range_is_writeback(inode, index, index);
450}
451
452/*
453 * Wait for page writeback to be completed.
454 *
455 * Since fuse doesn't rely on the VM writeback tracking, this has to
456 * use some other means.
457 */
458static void fuse_wait_on_page_writeback(struct inode *inode, pgoff_t index)
459{
460 struct fuse_inode *fi = get_fuse_inode(inode);
461
462 wait_event(fi->page_waitq, !fuse_page_is_writeback(inode, index));
463}
464
465/*
466 * Wait for all pending writepages on the inode to finish.
467 *
468 * This is currently done by blocking further writes with FUSE_NOWRITE
469 * and waiting for all sent writes to complete.
470 *
471 * This must be called under i_mutex, otherwise the FUSE_NOWRITE usage
472 * could conflict with truncation.
473 */
474static void fuse_sync_writes(struct inode *inode)
475{
476 fuse_set_nowrite(inode);
477 fuse_release_nowrite(inode);
478}
479
480static int fuse_flush(struct file *file, fl_owner_t id)
481{
482 struct inode *inode = file_inode(file);
483 struct fuse_mount *fm = get_fuse_mount(inode);
484 struct fuse_file *ff = file->private_data;
485 struct fuse_flush_in inarg;
486 FUSE_ARGS(args);
487 int err;
488
489 if (fuse_is_bad(inode))
490 return -EIO;
491
492 if (ff->open_flags & FOPEN_NOFLUSH && !fm->fc->writeback_cache)
493 return 0;
494
495 err = write_inode_now(inode, 1);
496 if (err)
497 return err;
498
499 inode_lock(inode);
500 fuse_sync_writes(inode);
501 inode_unlock(inode);
502
503 err = filemap_check_errors(file->f_mapping);
504 if (err)
505 return err;
506
507 err = 0;
508 if (fm->fc->no_flush)
509 goto inval_attr_out;
510
511 memset(&inarg, 0, sizeof(inarg));
512 inarg.fh = ff->fh;
513 inarg.lock_owner = fuse_lock_owner_id(fm->fc, id);
514 args.opcode = FUSE_FLUSH;
515 args.nodeid = get_node_id(inode);
516 args.in_numargs = 1;
517 args.in_args[0].size = sizeof(inarg);
518 args.in_args[0].value = &inarg;
519 args.force = true;
520
521 err = fuse_simple_request(fm, &args);
522 if (err == -ENOSYS) {
523 fm->fc->no_flush = 1;
524 err = 0;
525 }
526
527inval_attr_out:
528 /*
529 * In memory i_blocks is not maintained by fuse, if writeback cache is
530 * enabled, i_blocks from cached attr may not be accurate.
531 */
532 if (!err && fm->fc->writeback_cache)
533 fuse_invalidate_attr_mask(inode, STATX_BLOCKS);
534 return err;
535}
536
537int fuse_fsync_common(struct file *file, loff_t start, loff_t end,
538 int datasync, int opcode)
539{
540 struct inode *inode = file->f_mapping->host;
541 struct fuse_mount *fm = get_fuse_mount(inode);
542 struct fuse_file *ff = file->private_data;
543 FUSE_ARGS(args);
544 struct fuse_fsync_in inarg;
545
546 memset(&inarg, 0, sizeof(inarg));
547 inarg.fh = ff->fh;
548 inarg.fsync_flags = datasync ? FUSE_FSYNC_FDATASYNC : 0;
549 args.opcode = opcode;
550 args.nodeid = get_node_id(inode);
551 args.in_numargs = 1;
552 args.in_args[0].size = sizeof(inarg);
553 args.in_args[0].value = &inarg;
554 return fuse_simple_request(fm, &args);
555}
556
557static int fuse_fsync(struct file *file, loff_t start, loff_t end,
558 int datasync)
559{
560 struct inode *inode = file->f_mapping->host;
561 struct fuse_conn *fc = get_fuse_conn(inode);
562 int err;
563
564 if (fuse_is_bad(inode))
565 return -EIO;
566
567 inode_lock(inode);
568
569 /*
570 * Start writeback against all dirty pages of the inode, then
571 * wait for all outstanding writes, before sending the FSYNC
572 * request.
573 */
574 err = file_write_and_wait_range(file, start, end);
575 if (err)
576 goto out;
577
578 fuse_sync_writes(inode);
579
580 /*
581 * Due to implementation of fuse writeback
582 * file_write_and_wait_range() does not catch errors.
583 * We have to do this directly after fuse_sync_writes()
584 */
585 err = file_check_and_advance_wb_err(file);
586 if (err)
587 goto out;
588
589 err = sync_inode_metadata(inode, 1);
590 if (err)
591 goto out;
592
593 if (fc->no_fsync)
594 goto out;
595
596 err = fuse_fsync_common(file, start, end, datasync, FUSE_FSYNC);
597 if (err == -ENOSYS) {
598 fc->no_fsync = 1;
599 err = 0;
600 }
601out:
602 inode_unlock(inode);
603
604 return err;
605}
606
607void fuse_read_args_fill(struct fuse_io_args *ia, struct file *file, loff_t pos,
608 size_t count, int opcode)
609{
610 struct fuse_file *ff = file->private_data;
611 struct fuse_args *args = &ia->ap.args;
612
613 ia->read.in.fh = ff->fh;
614 ia->read.in.offset = pos;
615 ia->read.in.size = count;
616 ia->read.in.flags = file->f_flags;
617 args->opcode = opcode;
618 args->nodeid = ff->nodeid;
619 args->in_numargs = 1;
620 args->in_args[0].size = sizeof(ia->read.in);
621 args->in_args[0].value = &ia->read.in;
622 args->out_argvar = true;
623 args->out_numargs = 1;
624 args->out_args[0].size = count;
625}
626
627static void fuse_release_user_pages(struct fuse_args_pages *ap,
628 bool should_dirty)
629{
630 unsigned int i;
631
632 for (i = 0; i < ap->num_pages; i++) {
633 if (should_dirty)
634 set_page_dirty_lock(ap->pages[i]);
635 put_page(ap->pages[i]);
636 }
637}
638
639static void fuse_io_release(struct kref *kref)
640{
641 kfree(container_of(kref, struct fuse_io_priv, refcnt));
642}
643
644static ssize_t fuse_get_res_by_io(struct fuse_io_priv *io)
645{
646 if (io->err)
647 return io->err;
648
649 if (io->bytes >= 0 && io->write)
650 return -EIO;
651
652 return io->bytes < 0 ? io->size : io->bytes;
653}
654
655/**
656 * In case of short read, the caller sets 'pos' to the position of
657 * actual end of fuse request in IO request. Otherwise, if bytes_requested
658 * == bytes_transferred or rw == WRITE, the caller sets 'pos' to -1.
659 *
660 * An example:
661 * User requested DIO read of 64K. It was split into two 32K fuse requests,
662 * both submitted asynchronously. The first of them was ACKed by userspace as
663 * fully completed (req->out.args[0].size == 32K) resulting in pos == -1. The
664 * second request was ACKed as short, e.g. only 1K was read, resulting in
665 * pos == 33K.
666 *
667 * Thus, when all fuse requests are completed, the minimal non-negative 'pos'
668 * will be equal to the length of the longest contiguous fragment of
669 * transferred data starting from the beginning of IO request.
670 */
671static void fuse_aio_complete(struct fuse_io_priv *io, int err, ssize_t pos)
672{
673 int left;
674
675 spin_lock(&io->lock);
676 if (err)
677 io->err = io->err ? : err;
678 else if (pos >= 0 && (io->bytes < 0 || pos < io->bytes))
679 io->bytes = pos;
680
681 left = --io->reqs;
682 if (!left && io->blocking)
683 complete(io->done);
684 spin_unlock(&io->lock);
685
686 if (!left && !io->blocking) {
687 ssize_t res = fuse_get_res_by_io(io);
688
689 if (res >= 0) {
690 struct inode *inode = file_inode(io->iocb->ki_filp);
691 struct fuse_conn *fc = get_fuse_conn(inode);
692 struct fuse_inode *fi = get_fuse_inode(inode);
693
694 spin_lock(&fi->lock);
695 fi->attr_version = atomic64_inc_return(&fc->attr_version);
696 spin_unlock(&fi->lock);
697 }
698
699 io->iocb->ki_complete(io->iocb, res);
700 }
701
702 kref_put(&io->refcnt, fuse_io_release);
703}
704
705static struct fuse_io_args *fuse_io_alloc(struct fuse_io_priv *io,
706 unsigned int npages)
707{
708 struct fuse_io_args *ia;
709
710 ia = kzalloc(sizeof(*ia), GFP_KERNEL);
711 if (ia) {
712 ia->io = io;
713 ia->ap.pages = fuse_pages_alloc(npages, GFP_KERNEL,
714 &ia->ap.descs);
715 if (!ia->ap.pages) {
716 kfree(ia);
717 ia = NULL;
718 }
719 }
720 return ia;
721}
722
723static void fuse_io_free(struct fuse_io_args *ia)
724{
725 kfree(ia->ap.pages);
726 kfree(ia);
727}
728
729static void fuse_aio_complete_req(struct fuse_mount *fm, struct fuse_args *args,
730 int err)
731{
732 struct fuse_io_args *ia = container_of(args, typeof(*ia), ap.args);
733 struct fuse_io_priv *io = ia->io;
734 ssize_t pos = -1;
735
736 fuse_release_user_pages(&ia->ap, io->should_dirty);
737
738 if (err) {
739 /* Nothing */
740 } else if (io->write) {
741 if (ia->write.out.size > ia->write.in.size) {
742 err = -EIO;
743 } else if (ia->write.in.size != ia->write.out.size) {
744 pos = ia->write.in.offset - io->offset +
745 ia->write.out.size;
746 }
747 } else {
748 u32 outsize = args->out_args[0].size;
749
750 if (ia->read.in.size != outsize)
751 pos = ia->read.in.offset - io->offset + outsize;
752 }
753
754 fuse_aio_complete(io, err, pos);
755 fuse_io_free(ia);
756}
757
758static ssize_t fuse_async_req_send(struct fuse_mount *fm,
759 struct fuse_io_args *ia, size_t num_bytes)
760{
761 ssize_t err;
762 struct fuse_io_priv *io = ia->io;
763
764 spin_lock(&io->lock);
765 kref_get(&io->refcnt);
766 io->size += num_bytes;
767 io->reqs++;
768 spin_unlock(&io->lock);
769
770 ia->ap.args.end = fuse_aio_complete_req;
771 ia->ap.args.may_block = io->should_dirty;
772 err = fuse_simple_background(fm, &ia->ap.args, GFP_KERNEL);
773 if (err)
774 fuse_aio_complete_req(fm, &ia->ap.args, err);
775
776 return num_bytes;
777}
778
779static ssize_t fuse_send_read(struct fuse_io_args *ia, loff_t pos, size_t count,
780 fl_owner_t owner)
781{
782 struct file *file = ia->io->iocb->ki_filp;
783 struct fuse_file *ff = file->private_data;
784 struct fuse_mount *fm = ff->fm;
785
786 fuse_read_args_fill(ia, file, pos, count, FUSE_READ);
787 if (owner != NULL) {
788 ia->read.in.read_flags |= FUSE_READ_LOCKOWNER;
789 ia->read.in.lock_owner = fuse_lock_owner_id(fm->fc, owner);
790 }
791
792 if (ia->io->async)
793 return fuse_async_req_send(fm, ia, count);
794
795 return fuse_simple_request(fm, &ia->ap.args);
796}
797
798static void fuse_read_update_size(struct inode *inode, loff_t size,
799 u64 attr_ver)
800{
801 struct fuse_conn *fc = get_fuse_conn(inode);
802 struct fuse_inode *fi = get_fuse_inode(inode);
803
804 spin_lock(&fi->lock);
805 if (attr_ver >= fi->attr_version && size < inode->i_size &&
806 !test_bit(FUSE_I_SIZE_UNSTABLE, &fi->state)) {
807 fi->attr_version = atomic64_inc_return(&fc->attr_version);
808 i_size_write(inode, size);
809 }
810 spin_unlock(&fi->lock);
811}
812
813static void fuse_short_read(struct inode *inode, u64 attr_ver, size_t num_read,
814 struct fuse_args_pages *ap)
815{
816 struct fuse_conn *fc = get_fuse_conn(inode);
817
818 /*
819 * If writeback_cache is enabled, a short read means there's a hole in
820 * the file. Some data after the hole is in page cache, but has not
821 * reached the client fs yet. So the hole is not present there.
822 */
823 if (!fc->writeback_cache) {
824 loff_t pos = page_offset(ap->pages[0]) + num_read;
825 fuse_read_update_size(inode, pos, attr_ver);
826 }
827}
828
829static int fuse_do_readpage(struct file *file, struct page *page)
830{
831 struct inode *inode = page->mapping->host;
832 struct fuse_mount *fm = get_fuse_mount(inode);
833 loff_t pos = page_offset(page);
834 struct fuse_page_desc desc = { .length = PAGE_SIZE };
835 struct fuse_io_args ia = {
836 .ap.args.page_zeroing = true,
837 .ap.args.out_pages = true,
838 .ap.num_pages = 1,
839 .ap.pages = &page,
840 .ap.descs = &desc,
841 };
842 ssize_t res;
843 u64 attr_ver;
844
845 /*
846 * Page writeback can extend beyond the lifetime of the
847 * page-cache page, so make sure we read a properly synced
848 * page.
849 */
850 fuse_wait_on_page_writeback(inode, page->index);
851
852 attr_ver = fuse_get_attr_version(fm->fc);
853
854 /* Don't overflow end offset */
855 if (pos + (desc.length - 1) == LLONG_MAX)
856 desc.length--;
857
858 fuse_read_args_fill(&ia, file, pos, desc.length, FUSE_READ);
859 res = fuse_simple_request(fm, &ia.ap.args);
860 if (res < 0)
861 return res;
862 /*
863 * Short read means EOF. If file size is larger, truncate it
864 */
865 if (res < desc.length)
866 fuse_short_read(inode, attr_ver, res, &ia.ap);
867
868 SetPageUptodate(page);
869
870 return 0;
871}
872
873static int fuse_read_folio(struct file *file, struct folio *folio)
874{
875 struct page *page = &folio->page;
876 struct inode *inode = page->mapping->host;
877 int err;
878
879 err = -EIO;
880 if (fuse_is_bad(inode))
881 goto out;
882
883 err = fuse_do_readpage(file, page);
884 fuse_invalidate_atime(inode);
885 out:
886 unlock_page(page);
887 return err;
888}
889
890static void fuse_readpages_end(struct fuse_mount *fm, struct fuse_args *args,
891 int err)
892{
893 int i;
894 struct fuse_io_args *ia = container_of(args, typeof(*ia), ap.args);
895 struct fuse_args_pages *ap = &ia->ap;
896 size_t count = ia->read.in.size;
897 size_t num_read = args->out_args[0].size;
898 struct address_space *mapping = NULL;
899
900 for (i = 0; mapping == NULL && i < ap->num_pages; i++)
901 mapping = ap->pages[i]->mapping;
902
903 if (mapping) {
904 struct inode *inode = mapping->host;
905
906 /*
907 * Short read means EOF. If file size is larger, truncate it
908 */
909 if (!err && num_read < count)
910 fuse_short_read(inode, ia->read.attr_ver, num_read, ap);
911
912 fuse_invalidate_atime(inode);
913 }
914
915 for (i = 0; i < ap->num_pages; i++) {
916 struct page *page = ap->pages[i];
917
918 if (!err)
919 SetPageUptodate(page);
920 else
921 SetPageError(page);
922 unlock_page(page);
923 put_page(page);
924 }
925 if (ia->ff)
926 fuse_file_put(ia->ff, false, false);
927
928 fuse_io_free(ia);
929}
930
931static void fuse_send_readpages(struct fuse_io_args *ia, struct file *file)
932{
933 struct fuse_file *ff = file->private_data;
934 struct fuse_mount *fm = ff->fm;
935 struct fuse_args_pages *ap = &ia->ap;
936 loff_t pos = page_offset(ap->pages[0]);
937 size_t count = ap->num_pages << PAGE_SHIFT;
938 ssize_t res;
939 int err;
940
941 ap->args.out_pages = true;
942 ap->args.page_zeroing = true;
943 ap->args.page_replace = true;
944
945 /* Don't overflow end offset */
946 if (pos + (count - 1) == LLONG_MAX) {
947 count--;
948 ap->descs[ap->num_pages - 1].length--;
949 }
950 WARN_ON((loff_t) (pos + count) < 0);
951
952 fuse_read_args_fill(ia, file, pos, count, FUSE_READ);
953 ia->read.attr_ver = fuse_get_attr_version(fm->fc);
954 if (fm->fc->async_read) {
955 ia->ff = fuse_file_get(ff);
956 ap->args.end = fuse_readpages_end;
957 err = fuse_simple_background(fm, &ap->args, GFP_KERNEL);
958 if (!err)
959 return;
960 } else {
961 res = fuse_simple_request(fm, &ap->args);
962 err = res < 0 ? res : 0;
963 }
964 fuse_readpages_end(fm, &ap->args, err);
965}
966
967static void fuse_readahead(struct readahead_control *rac)
968{
969 struct inode *inode = rac->mapping->host;
970 struct fuse_conn *fc = get_fuse_conn(inode);
971 unsigned int i, max_pages, nr_pages = 0;
972
973 if (fuse_is_bad(inode))
974 return;
975
976 max_pages = min_t(unsigned int, fc->max_pages,
977 fc->max_read / PAGE_SIZE);
978
979 for (;;) {
980 struct fuse_io_args *ia;
981 struct fuse_args_pages *ap;
982
983 if (fc->num_background >= fc->congestion_threshold &&
984 rac->ra->async_size >= readahead_count(rac))
985 /*
986 * Congested and only async pages left, so skip the
987 * rest.
988 */
989 break;
990
991 nr_pages = readahead_count(rac) - nr_pages;
992 if (nr_pages > max_pages)
993 nr_pages = max_pages;
994 if (nr_pages == 0)
995 break;
996 ia = fuse_io_alloc(NULL, nr_pages);
997 if (!ia)
998 return;
999 ap = &ia->ap;
1000 nr_pages = __readahead_batch(rac, ap->pages, nr_pages);
1001 for (i = 0; i < nr_pages; i++) {
1002 fuse_wait_on_page_writeback(inode,
1003 readahead_index(rac) + i);
1004 ap->descs[i].length = PAGE_SIZE;
1005 }
1006 ap->num_pages = nr_pages;
1007 fuse_send_readpages(ia, rac->file);
1008 }
1009}
1010
1011static ssize_t fuse_cache_read_iter(struct kiocb *iocb, struct iov_iter *to)
1012{
1013 struct inode *inode = iocb->ki_filp->f_mapping->host;
1014 struct fuse_conn *fc = get_fuse_conn(inode);
1015
1016 /*
1017 * In auto invalidate mode, always update attributes on read.
1018 * Otherwise, only update if we attempt to read past EOF (to ensure
1019 * i_size is up to date).
1020 */
1021 if (fc->auto_inval_data ||
1022 (iocb->ki_pos + iov_iter_count(to) > i_size_read(inode))) {
1023 int err;
1024 err = fuse_update_attributes(inode, iocb->ki_filp, STATX_SIZE);
1025 if (err)
1026 return err;
1027 }
1028
1029 return generic_file_read_iter(iocb, to);
1030}
1031
1032static void fuse_write_args_fill(struct fuse_io_args *ia, struct fuse_file *ff,
1033 loff_t pos, size_t count)
1034{
1035 struct fuse_args *args = &ia->ap.args;
1036
1037 ia->write.in.fh = ff->fh;
1038 ia->write.in.offset = pos;
1039 ia->write.in.size = count;
1040 args->opcode = FUSE_WRITE;
1041 args->nodeid = ff->nodeid;
1042 args->in_numargs = 2;
1043 if (ff->fm->fc->minor < 9)
1044 args->in_args[0].size = FUSE_COMPAT_WRITE_IN_SIZE;
1045 else
1046 args->in_args[0].size = sizeof(ia->write.in);
1047 args->in_args[0].value = &ia->write.in;
1048 args->in_args[1].size = count;
1049 args->out_numargs = 1;
1050 args->out_args[0].size = sizeof(ia->write.out);
1051 args->out_args[0].value = &ia->write.out;
1052}
1053
1054static unsigned int fuse_write_flags(struct kiocb *iocb)
1055{
1056 unsigned int flags = iocb->ki_filp->f_flags;
1057
1058 if (iocb_is_dsync(iocb))
1059 flags |= O_DSYNC;
1060 if (iocb->ki_flags & IOCB_SYNC)
1061 flags |= O_SYNC;
1062
1063 return flags;
1064}
1065
1066static ssize_t fuse_send_write(struct fuse_io_args *ia, loff_t pos,
1067 size_t count, fl_owner_t owner)
1068{
1069 struct kiocb *iocb = ia->io->iocb;
1070 struct file *file = iocb->ki_filp;
1071 struct fuse_file *ff = file->private_data;
1072 struct fuse_mount *fm = ff->fm;
1073 struct fuse_write_in *inarg = &ia->write.in;
1074 ssize_t err;
1075
1076 fuse_write_args_fill(ia, ff, pos, count);
1077 inarg->flags = fuse_write_flags(iocb);
1078 if (owner != NULL) {
1079 inarg->write_flags |= FUSE_WRITE_LOCKOWNER;
1080 inarg->lock_owner = fuse_lock_owner_id(fm->fc, owner);
1081 }
1082
1083 if (ia->io->async)
1084 return fuse_async_req_send(fm, ia, count);
1085
1086 err = fuse_simple_request(fm, &ia->ap.args);
1087 if (!err && ia->write.out.size > count)
1088 err = -EIO;
1089
1090 return err ?: ia->write.out.size;
1091}
1092
1093bool fuse_write_update_attr(struct inode *inode, loff_t pos, ssize_t written)
1094{
1095 struct fuse_conn *fc = get_fuse_conn(inode);
1096 struct fuse_inode *fi = get_fuse_inode(inode);
1097 bool ret = false;
1098
1099 spin_lock(&fi->lock);
1100 fi->attr_version = atomic64_inc_return(&fc->attr_version);
1101 if (written > 0 && pos > inode->i_size) {
1102 i_size_write(inode, pos);
1103 ret = true;
1104 }
1105 spin_unlock(&fi->lock);
1106
1107 fuse_invalidate_attr_mask(inode, FUSE_STATX_MODSIZE);
1108
1109 return ret;
1110}
1111
1112static ssize_t fuse_send_write_pages(struct fuse_io_args *ia,
1113 struct kiocb *iocb, struct inode *inode,
1114 loff_t pos, size_t count)
1115{
1116 struct fuse_args_pages *ap = &ia->ap;
1117 struct file *file = iocb->ki_filp;
1118 struct fuse_file *ff = file->private_data;
1119 struct fuse_mount *fm = ff->fm;
1120 unsigned int offset, i;
1121 bool short_write;
1122 int err;
1123
1124 for (i = 0; i < ap->num_pages; i++)
1125 fuse_wait_on_page_writeback(inode, ap->pages[i]->index);
1126
1127 fuse_write_args_fill(ia, ff, pos, count);
1128 ia->write.in.flags = fuse_write_flags(iocb);
1129 if (fm->fc->handle_killpriv_v2 && !capable(CAP_FSETID))
1130 ia->write.in.write_flags |= FUSE_WRITE_KILL_SUIDGID;
1131
1132 err = fuse_simple_request(fm, &ap->args);
1133 if (!err && ia->write.out.size > count)
1134 err = -EIO;
1135
1136 short_write = ia->write.out.size < count;
1137 offset = ap->descs[0].offset;
1138 count = ia->write.out.size;
1139 for (i = 0; i < ap->num_pages; i++) {
1140 struct page *page = ap->pages[i];
1141
1142 if (err) {
1143 ClearPageUptodate(page);
1144 } else {
1145 if (count >= PAGE_SIZE - offset)
1146 count -= PAGE_SIZE - offset;
1147 else {
1148 if (short_write)
1149 ClearPageUptodate(page);
1150 count = 0;
1151 }
1152 offset = 0;
1153 }
1154 if (ia->write.page_locked && (i == ap->num_pages - 1))
1155 unlock_page(page);
1156 put_page(page);
1157 }
1158
1159 return err;
1160}
1161
1162static ssize_t fuse_fill_write_pages(struct fuse_io_args *ia,
1163 struct address_space *mapping,
1164 struct iov_iter *ii, loff_t pos,
1165 unsigned int max_pages)
1166{
1167 struct fuse_args_pages *ap = &ia->ap;
1168 struct fuse_conn *fc = get_fuse_conn(mapping->host);
1169 unsigned offset = pos & (PAGE_SIZE - 1);
1170 size_t count = 0;
1171 int err;
1172
1173 ap->args.in_pages = true;
1174 ap->descs[0].offset = offset;
1175
1176 do {
1177 size_t tmp;
1178 struct page *page;
1179 pgoff_t index = pos >> PAGE_SHIFT;
1180 size_t bytes = min_t(size_t, PAGE_SIZE - offset,
1181 iov_iter_count(ii));
1182
1183 bytes = min_t(size_t, bytes, fc->max_write - count);
1184
1185 again:
1186 err = -EFAULT;
1187 if (fault_in_iov_iter_readable(ii, bytes))
1188 break;
1189
1190 err = -ENOMEM;
1191 page = grab_cache_page_write_begin(mapping, index);
1192 if (!page)
1193 break;
1194
1195 if (mapping_writably_mapped(mapping))
1196 flush_dcache_page(page);
1197
1198 tmp = copy_page_from_iter_atomic(page, offset, bytes, ii);
1199 flush_dcache_page(page);
1200
1201 if (!tmp) {
1202 unlock_page(page);
1203 put_page(page);
1204 goto again;
1205 }
1206
1207 err = 0;
1208 ap->pages[ap->num_pages] = page;
1209 ap->descs[ap->num_pages].length = tmp;
1210 ap->num_pages++;
1211
1212 count += tmp;
1213 pos += tmp;
1214 offset += tmp;
1215 if (offset == PAGE_SIZE)
1216 offset = 0;
1217
1218 /* If we copied full page, mark it uptodate */
1219 if (tmp == PAGE_SIZE)
1220 SetPageUptodate(page);
1221
1222 if (PageUptodate(page)) {
1223 unlock_page(page);
1224 } else {
1225 ia->write.page_locked = true;
1226 break;
1227 }
1228 if (!fc->big_writes)
1229 break;
1230 } while (iov_iter_count(ii) && count < fc->max_write &&
1231 ap->num_pages < max_pages && offset == 0);
1232
1233 return count > 0 ? count : err;
1234}
1235
1236static inline unsigned int fuse_wr_pages(loff_t pos, size_t len,
1237 unsigned int max_pages)
1238{
1239 return min_t(unsigned int,
1240 ((pos + len - 1) >> PAGE_SHIFT) -
1241 (pos >> PAGE_SHIFT) + 1,
1242 max_pages);
1243}
1244
1245static ssize_t fuse_perform_write(struct kiocb *iocb,
1246 struct address_space *mapping,
1247 struct iov_iter *ii, loff_t pos)
1248{
1249 struct inode *inode = mapping->host;
1250 struct fuse_conn *fc = get_fuse_conn(inode);
1251 struct fuse_inode *fi = get_fuse_inode(inode);
1252 int err = 0;
1253 ssize_t res = 0;
1254
1255 if (inode->i_size < pos + iov_iter_count(ii))
1256 set_bit(FUSE_I_SIZE_UNSTABLE, &fi->state);
1257
1258 do {
1259 ssize_t count;
1260 struct fuse_io_args ia = {};
1261 struct fuse_args_pages *ap = &ia.ap;
1262 unsigned int nr_pages = fuse_wr_pages(pos, iov_iter_count(ii),
1263 fc->max_pages);
1264
1265 ap->pages = fuse_pages_alloc(nr_pages, GFP_KERNEL, &ap->descs);
1266 if (!ap->pages) {
1267 err = -ENOMEM;
1268 break;
1269 }
1270
1271 count = fuse_fill_write_pages(&ia, mapping, ii, pos, nr_pages);
1272 if (count <= 0) {
1273 err = count;
1274 } else {
1275 err = fuse_send_write_pages(&ia, iocb, inode,
1276 pos, count);
1277 if (!err) {
1278 size_t num_written = ia.write.out.size;
1279
1280 res += num_written;
1281 pos += num_written;
1282
1283 /* break out of the loop on short write */
1284 if (num_written != count)
1285 err = -EIO;
1286 }
1287 }
1288 kfree(ap->pages);
1289 } while (!err && iov_iter_count(ii));
1290
1291 fuse_write_update_attr(inode, pos, res);
1292 clear_bit(FUSE_I_SIZE_UNSTABLE, &fi->state);
1293
1294 return res > 0 ? res : err;
1295}
1296
1297static ssize_t fuse_cache_write_iter(struct kiocb *iocb, struct iov_iter *from)
1298{
1299 struct file *file = iocb->ki_filp;
1300 struct address_space *mapping = file->f_mapping;
1301 ssize_t written = 0;
1302 ssize_t written_buffered = 0;
1303 struct inode *inode = mapping->host;
1304 ssize_t err;
1305 struct fuse_conn *fc = get_fuse_conn(inode);
1306 loff_t endbyte = 0;
1307
1308 if (fc->writeback_cache) {
1309 /* Update size (EOF optimization) and mode (SUID clearing) */
1310 err = fuse_update_attributes(mapping->host, file,
1311 STATX_SIZE | STATX_MODE);
1312 if (err)
1313 return err;
1314
1315 if (fc->handle_killpriv_v2 &&
1316 setattr_should_drop_suidgid(&init_user_ns, file_inode(file))) {
1317 goto writethrough;
1318 }
1319
1320 return generic_file_write_iter(iocb, from);
1321 }
1322
1323writethrough:
1324 inode_lock(inode);
1325
1326 /* We can write back this queue in page reclaim */
1327 current->backing_dev_info = inode_to_bdi(inode);
1328
1329 err = generic_write_checks(iocb, from);
1330 if (err <= 0)
1331 goto out;
1332
1333 err = file_remove_privs(file);
1334 if (err)
1335 goto out;
1336
1337 err = file_update_time(file);
1338 if (err)
1339 goto out;
1340
1341 if (iocb->ki_flags & IOCB_DIRECT) {
1342 loff_t pos = iocb->ki_pos;
1343 written = generic_file_direct_write(iocb, from);
1344 if (written < 0 || !iov_iter_count(from))
1345 goto out;
1346
1347 pos += written;
1348
1349 written_buffered = fuse_perform_write(iocb, mapping, from, pos);
1350 if (written_buffered < 0) {
1351 err = written_buffered;
1352 goto out;
1353 }
1354 endbyte = pos + written_buffered - 1;
1355
1356 err = filemap_write_and_wait_range(file->f_mapping, pos,
1357 endbyte);
1358 if (err)
1359 goto out;
1360
1361 invalidate_mapping_pages(file->f_mapping,
1362 pos >> PAGE_SHIFT,
1363 endbyte >> PAGE_SHIFT);
1364
1365 written += written_buffered;
1366 iocb->ki_pos = pos + written_buffered;
1367 } else {
1368 written = fuse_perform_write(iocb, mapping, from, iocb->ki_pos);
1369 if (written >= 0)
1370 iocb->ki_pos += written;
1371 }
1372out:
1373 current->backing_dev_info = NULL;
1374 inode_unlock(inode);
1375 if (written > 0)
1376 written = generic_write_sync(iocb, written);
1377
1378 return written ? written : err;
1379}
1380
1381static inline unsigned long fuse_get_user_addr(const struct iov_iter *ii)
1382{
1383 return (unsigned long)ii->iov->iov_base + ii->iov_offset;
1384}
1385
1386static inline size_t fuse_get_frag_size(const struct iov_iter *ii,
1387 size_t max_size)
1388{
1389 return min(iov_iter_single_seg_count(ii), max_size);
1390}
1391
1392static int fuse_get_user_pages(struct fuse_args_pages *ap, struct iov_iter *ii,
1393 size_t *nbytesp, int write,
1394 unsigned int max_pages)
1395{
1396 size_t nbytes = 0; /* # bytes already packed in req */
1397 ssize_t ret = 0;
1398
1399 /* Special case for kernel I/O: can copy directly into the buffer */
1400 if (iov_iter_is_kvec(ii)) {
1401 unsigned long user_addr = fuse_get_user_addr(ii);
1402 size_t frag_size = fuse_get_frag_size(ii, *nbytesp);
1403
1404 if (write)
1405 ap->args.in_args[1].value = (void *) user_addr;
1406 else
1407 ap->args.out_args[0].value = (void *) user_addr;
1408
1409 iov_iter_advance(ii, frag_size);
1410 *nbytesp = frag_size;
1411 return 0;
1412 }
1413
1414 while (nbytes < *nbytesp && ap->num_pages < max_pages) {
1415 unsigned npages;
1416 size_t start;
1417 ret = iov_iter_get_pages2(ii, &ap->pages[ap->num_pages],
1418 *nbytesp - nbytes,
1419 max_pages - ap->num_pages,
1420 &start);
1421 if (ret < 0)
1422 break;
1423
1424 nbytes += ret;
1425
1426 ret += start;
1427 npages = DIV_ROUND_UP(ret, PAGE_SIZE);
1428
1429 ap->descs[ap->num_pages].offset = start;
1430 fuse_page_descs_length_init(ap->descs, ap->num_pages, npages);
1431
1432 ap->num_pages += npages;
1433 ap->descs[ap->num_pages - 1].length -=
1434 (PAGE_SIZE - ret) & (PAGE_SIZE - 1);
1435 }
1436
1437 ap->args.user_pages = true;
1438 if (write)
1439 ap->args.in_pages = true;
1440 else
1441 ap->args.out_pages = true;
1442
1443 *nbytesp = nbytes;
1444
1445 return ret < 0 ? ret : 0;
1446}
1447
1448ssize_t fuse_direct_io(struct fuse_io_priv *io, struct iov_iter *iter,
1449 loff_t *ppos, int flags)
1450{
1451 int write = flags & FUSE_DIO_WRITE;
1452 int cuse = flags & FUSE_DIO_CUSE;
1453 struct file *file = io->iocb->ki_filp;
1454 struct inode *inode = file->f_mapping->host;
1455 struct fuse_file *ff = file->private_data;
1456 struct fuse_conn *fc = ff->fm->fc;
1457 size_t nmax = write ? fc->max_write : fc->max_read;
1458 loff_t pos = *ppos;
1459 size_t count = iov_iter_count(iter);
1460 pgoff_t idx_from = pos >> PAGE_SHIFT;
1461 pgoff_t idx_to = (pos + count - 1) >> PAGE_SHIFT;
1462 ssize_t res = 0;
1463 int err = 0;
1464 struct fuse_io_args *ia;
1465 unsigned int max_pages;
1466
1467 max_pages = iov_iter_npages(iter, fc->max_pages);
1468 ia = fuse_io_alloc(io, max_pages);
1469 if (!ia)
1470 return -ENOMEM;
1471
1472 if (!cuse && fuse_range_is_writeback(inode, idx_from, idx_to)) {
1473 if (!write)
1474 inode_lock(inode);
1475 fuse_sync_writes(inode);
1476 if (!write)
1477 inode_unlock(inode);
1478 }
1479
1480 io->should_dirty = !write && user_backed_iter(iter);
1481 while (count) {
1482 ssize_t nres;
1483 fl_owner_t owner = current->files;
1484 size_t nbytes = min(count, nmax);
1485
1486 err = fuse_get_user_pages(&ia->ap, iter, &nbytes, write,
1487 max_pages);
1488 if (err && !nbytes)
1489 break;
1490
1491 if (write) {
1492 if (!capable(CAP_FSETID))
1493 ia->write.in.write_flags |= FUSE_WRITE_KILL_SUIDGID;
1494
1495 nres = fuse_send_write(ia, pos, nbytes, owner);
1496 } else {
1497 nres = fuse_send_read(ia, pos, nbytes, owner);
1498 }
1499
1500 if (!io->async || nres < 0) {
1501 fuse_release_user_pages(&ia->ap, io->should_dirty);
1502 fuse_io_free(ia);
1503 }
1504 ia = NULL;
1505 if (nres < 0) {
1506 iov_iter_revert(iter, nbytes);
1507 err = nres;
1508 break;
1509 }
1510 WARN_ON(nres > nbytes);
1511
1512 count -= nres;
1513 res += nres;
1514 pos += nres;
1515 if (nres != nbytes) {
1516 iov_iter_revert(iter, nbytes - nres);
1517 break;
1518 }
1519 if (count) {
1520 max_pages = iov_iter_npages(iter, fc->max_pages);
1521 ia = fuse_io_alloc(io, max_pages);
1522 if (!ia)
1523 break;
1524 }
1525 }
1526 if (ia)
1527 fuse_io_free(ia);
1528 if (res > 0)
1529 *ppos = pos;
1530
1531 return res > 0 ? res : err;
1532}
1533EXPORT_SYMBOL_GPL(fuse_direct_io);
1534
1535static ssize_t __fuse_direct_read(struct fuse_io_priv *io,
1536 struct iov_iter *iter,
1537 loff_t *ppos)
1538{
1539 ssize_t res;
1540 struct inode *inode = file_inode(io->iocb->ki_filp);
1541
1542 res = fuse_direct_io(io, iter, ppos, 0);
1543
1544 fuse_invalidate_atime(inode);
1545
1546 return res;
1547}
1548
1549static ssize_t fuse_direct_IO(struct kiocb *iocb, struct iov_iter *iter);
1550
1551static ssize_t fuse_direct_read_iter(struct kiocb *iocb, struct iov_iter *to)
1552{
1553 ssize_t res;
1554
1555 if (!is_sync_kiocb(iocb) && iocb->ki_flags & IOCB_DIRECT) {
1556 res = fuse_direct_IO(iocb, to);
1557 } else {
1558 struct fuse_io_priv io = FUSE_IO_PRIV_SYNC(iocb);
1559
1560 res = __fuse_direct_read(&io, to, &iocb->ki_pos);
1561 }
1562
1563 return res;
1564}
1565
1566static bool fuse_direct_write_extending_i_size(struct kiocb *iocb,
1567 struct iov_iter *iter)
1568{
1569 struct inode *inode = file_inode(iocb->ki_filp);
1570
1571 return iocb->ki_pos + iov_iter_count(iter) > i_size_read(inode);
1572}
1573
1574static ssize_t fuse_direct_write_iter(struct kiocb *iocb, struct iov_iter *from)
1575{
1576 struct inode *inode = file_inode(iocb->ki_filp);
1577 struct file *file = iocb->ki_filp;
1578 struct fuse_file *ff = file->private_data;
1579 struct fuse_io_priv io = FUSE_IO_PRIV_SYNC(iocb);
1580 ssize_t res;
1581 bool exclusive_lock =
1582 !(ff->open_flags & FOPEN_PARALLEL_DIRECT_WRITES) ||
1583 iocb->ki_flags & IOCB_APPEND ||
1584 fuse_direct_write_extending_i_size(iocb, from);
1585
1586 /*
1587 * Take exclusive lock if
1588 * - Parallel direct writes are disabled - a user space decision
1589 * - Parallel direct writes are enabled and i_size is being extended.
1590 * This might not be needed at all, but needs further investigation.
1591 */
1592 if (exclusive_lock)
1593 inode_lock(inode);
1594 else {
1595 inode_lock_shared(inode);
1596
1597 /* A race with truncate might have come up as the decision for
1598 * the lock type was done without holding the lock, check again.
1599 */
1600 if (fuse_direct_write_extending_i_size(iocb, from)) {
1601 inode_unlock_shared(inode);
1602 inode_lock(inode);
1603 exclusive_lock = true;
1604 }
1605 }
1606
1607 res = generic_write_checks(iocb, from);
1608 if (res > 0) {
1609 if (!is_sync_kiocb(iocb) && iocb->ki_flags & IOCB_DIRECT) {
1610 res = fuse_direct_IO(iocb, from);
1611 } else {
1612 res = fuse_direct_io(&io, from, &iocb->ki_pos,
1613 FUSE_DIO_WRITE);
1614 fuse_write_update_attr(inode, iocb->ki_pos, res);
1615 }
1616 }
1617 if (exclusive_lock)
1618 inode_unlock(inode);
1619 else
1620 inode_unlock_shared(inode);
1621
1622 return res;
1623}
1624
1625static ssize_t fuse_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
1626{
1627 struct file *file = iocb->ki_filp;
1628 struct fuse_file *ff = file->private_data;
1629 struct inode *inode = file_inode(file);
1630
1631 if (fuse_is_bad(inode))
1632 return -EIO;
1633
1634 if (FUSE_IS_DAX(inode))
1635 return fuse_dax_read_iter(iocb, to);
1636
1637 if (!(ff->open_flags & FOPEN_DIRECT_IO))
1638 return fuse_cache_read_iter(iocb, to);
1639 else
1640 return fuse_direct_read_iter(iocb, to);
1641}
1642
1643static ssize_t fuse_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
1644{
1645 struct file *file = iocb->ki_filp;
1646 struct fuse_file *ff = file->private_data;
1647 struct inode *inode = file_inode(file);
1648
1649 if (fuse_is_bad(inode))
1650 return -EIO;
1651
1652 if (FUSE_IS_DAX(inode))
1653 return fuse_dax_write_iter(iocb, from);
1654
1655 if (!(ff->open_flags & FOPEN_DIRECT_IO))
1656 return fuse_cache_write_iter(iocb, from);
1657 else
1658 return fuse_direct_write_iter(iocb, from);
1659}
1660
1661static void fuse_writepage_free(struct fuse_writepage_args *wpa)
1662{
1663 struct fuse_args_pages *ap = &wpa->ia.ap;
1664 int i;
1665
1666 if (wpa->bucket)
1667 fuse_sync_bucket_dec(wpa->bucket);
1668
1669 for (i = 0; i < ap->num_pages; i++)
1670 __free_page(ap->pages[i]);
1671
1672 if (wpa->ia.ff)
1673 fuse_file_put(wpa->ia.ff, false, false);
1674
1675 kfree(ap->pages);
1676 kfree(wpa);
1677}
1678
1679static void fuse_writepage_finish(struct fuse_mount *fm,
1680 struct fuse_writepage_args *wpa)
1681{
1682 struct fuse_args_pages *ap = &wpa->ia.ap;
1683 struct inode *inode = wpa->inode;
1684 struct fuse_inode *fi = get_fuse_inode(inode);
1685 struct backing_dev_info *bdi = inode_to_bdi(inode);
1686 int i;
1687
1688 for (i = 0; i < ap->num_pages; i++) {
1689 dec_wb_stat(&bdi->wb, WB_WRITEBACK);
1690 dec_node_page_state(ap->pages[i], NR_WRITEBACK_TEMP);
1691 wb_writeout_inc(&bdi->wb);
1692 }
1693 wake_up(&fi->page_waitq);
1694}
1695
1696/* Called under fi->lock, may release and reacquire it */
1697static void fuse_send_writepage(struct fuse_mount *fm,
1698 struct fuse_writepage_args *wpa, loff_t size)
1699__releases(fi->lock)
1700__acquires(fi->lock)
1701{
1702 struct fuse_writepage_args *aux, *next;
1703 struct fuse_inode *fi = get_fuse_inode(wpa->inode);
1704 struct fuse_write_in *inarg = &wpa->ia.write.in;
1705 struct fuse_args *args = &wpa->ia.ap.args;
1706 __u64 data_size = wpa->ia.ap.num_pages * PAGE_SIZE;
1707 int err;
1708
1709 fi->writectr++;
1710 if (inarg->offset + data_size <= size) {
1711 inarg->size = data_size;
1712 } else if (inarg->offset < size) {
1713 inarg->size = size - inarg->offset;
1714 } else {
1715 /* Got truncated off completely */
1716 goto out_free;
1717 }
1718
1719 args->in_args[1].size = inarg->size;
1720 args->force = true;
1721 args->nocreds = true;
1722
1723 err = fuse_simple_background(fm, args, GFP_ATOMIC);
1724 if (err == -ENOMEM) {
1725 spin_unlock(&fi->lock);
1726 err = fuse_simple_background(fm, args, GFP_NOFS | __GFP_NOFAIL);
1727 spin_lock(&fi->lock);
1728 }
1729
1730 /* Fails on broken connection only */
1731 if (unlikely(err))
1732 goto out_free;
1733
1734 return;
1735
1736 out_free:
1737 fi->writectr--;
1738 rb_erase(&wpa->writepages_entry, &fi->writepages);
1739 fuse_writepage_finish(fm, wpa);
1740 spin_unlock(&fi->lock);
1741
1742 /* After fuse_writepage_finish() aux request list is private */
1743 for (aux = wpa->next; aux; aux = next) {
1744 next = aux->next;
1745 aux->next = NULL;
1746 fuse_writepage_free(aux);
1747 }
1748
1749 fuse_writepage_free(wpa);
1750 spin_lock(&fi->lock);
1751}
1752
1753/*
1754 * If fi->writectr is positive (no truncate or fsync going on) send
1755 * all queued writepage requests.
1756 *
1757 * Called with fi->lock
1758 */
1759void fuse_flush_writepages(struct inode *inode)
1760__releases(fi->lock)
1761__acquires(fi->lock)
1762{
1763 struct fuse_mount *fm = get_fuse_mount(inode);
1764 struct fuse_inode *fi = get_fuse_inode(inode);
1765 loff_t crop = i_size_read(inode);
1766 struct fuse_writepage_args *wpa;
1767
1768 while (fi->writectr >= 0 && !list_empty(&fi->queued_writes)) {
1769 wpa = list_entry(fi->queued_writes.next,
1770 struct fuse_writepage_args, queue_entry);
1771 list_del_init(&wpa->queue_entry);
1772 fuse_send_writepage(fm, wpa, crop);
1773 }
1774}
1775
1776static struct fuse_writepage_args *fuse_insert_writeback(struct rb_root *root,
1777 struct fuse_writepage_args *wpa)
1778{
1779 pgoff_t idx_from = wpa->ia.write.in.offset >> PAGE_SHIFT;
1780 pgoff_t idx_to = idx_from + wpa->ia.ap.num_pages - 1;
1781 struct rb_node **p = &root->rb_node;
1782 struct rb_node *parent = NULL;
1783
1784 WARN_ON(!wpa->ia.ap.num_pages);
1785 while (*p) {
1786 struct fuse_writepage_args *curr;
1787 pgoff_t curr_index;
1788
1789 parent = *p;
1790 curr = rb_entry(parent, struct fuse_writepage_args,
1791 writepages_entry);
1792 WARN_ON(curr->inode != wpa->inode);
1793 curr_index = curr->ia.write.in.offset >> PAGE_SHIFT;
1794
1795 if (idx_from >= curr_index + curr->ia.ap.num_pages)
1796 p = &(*p)->rb_right;
1797 else if (idx_to < curr_index)
1798 p = &(*p)->rb_left;
1799 else
1800 return curr;
1801 }
1802
1803 rb_link_node(&wpa->writepages_entry, parent, p);
1804 rb_insert_color(&wpa->writepages_entry, root);
1805 return NULL;
1806}
1807
1808static void tree_insert(struct rb_root *root, struct fuse_writepage_args *wpa)
1809{
1810 WARN_ON(fuse_insert_writeback(root, wpa));
1811}
1812
1813static void fuse_writepage_end(struct fuse_mount *fm, struct fuse_args *args,
1814 int error)
1815{
1816 struct fuse_writepage_args *wpa =
1817 container_of(args, typeof(*wpa), ia.ap.args);
1818 struct inode *inode = wpa->inode;
1819 struct fuse_inode *fi = get_fuse_inode(inode);
1820 struct fuse_conn *fc = get_fuse_conn(inode);
1821
1822 mapping_set_error(inode->i_mapping, error);
1823 /*
1824 * A writeback finished and this might have updated mtime/ctime on
1825 * server making local mtime/ctime stale. Hence invalidate attrs.
1826 * Do this only if writeback_cache is not enabled. If writeback_cache
1827 * is enabled, we trust local ctime/mtime.
1828 */
1829 if (!fc->writeback_cache)
1830 fuse_invalidate_attr_mask(inode, FUSE_STATX_MODIFY);
1831 spin_lock(&fi->lock);
1832 rb_erase(&wpa->writepages_entry, &fi->writepages);
1833 while (wpa->next) {
1834 struct fuse_mount *fm = get_fuse_mount(inode);
1835 struct fuse_write_in *inarg = &wpa->ia.write.in;
1836 struct fuse_writepage_args *next = wpa->next;
1837
1838 wpa->next = next->next;
1839 next->next = NULL;
1840 next->ia.ff = fuse_file_get(wpa->ia.ff);
1841 tree_insert(&fi->writepages, next);
1842
1843 /*
1844 * Skip fuse_flush_writepages() to make it easy to crop requests
1845 * based on primary request size.
1846 *
1847 * 1st case (trivial): there are no concurrent activities using
1848 * fuse_set/release_nowrite. Then we're on safe side because
1849 * fuse_flush_writepages() would call fuse_send_writepage()
1850 * anyway.
1851 *
1852 * 2nd case: someone called fuse_set_nowrite and it is waiting
1853 * now for completion of all in-flight requests. This happens
1854 * rarely and no more than once per page, so this should be
1855 * okay.
1856 *
1857 * 3rd case: someone (e.g. fuse_do_setattr()) is in the middle
1858 * of fuse_set_nowrite..fuse_release_nowrite section. The fact
1859 * that fuse_set_nowrite returned implies that all in-flight
1860 * requests were completed along with all of their secondary
1861 * requests. Further primary requests are blocked by negative
1862 * writectr. Hence there cannot be any in-flight requests and
1863 * no invocations of fuse_writepage_end() while we're in
1864 * fuse_set_nowrite..fuse_release_nowrite section.
1865 */
1866 fuse_send_writepage(fm, next, inarg->offset + inarg->size);
1867 }
1868 fi->writectr--;
1869 fuse_writepage_finish(fm, wpa);
1870 spin_unlock(&fi->lock);
1871 fuse_writepage_free(wpa);
1872}
1873
1874static struct fuse_file *__fuse_write_file_get(struct fuse_inode *fi)
1875{
1876 struct fuse_file *ff;
1877
1878 spin_lock(&fi->lock);
1879 ff = list_first_entry_or_null(&fi->write_files, struct fuse_file,
1880 write_entry);
1881 if (ff)
1882 fuse_file_get(ff);
1883 spin_unlock(&fi->lock);
1884
1885 return ff;
1886}
1887
1888static struct fuse_file *fuse_write_file_get(struct fuse_inode *fi)
1889{
1890 struct fuse_file *ff = __fuse_write_file_get(fi);
1891 WARN_ON(!ff);
1892 return ff;
1893}
1894
1895int fuse_write_inode(struct inode *inode, struct writeback_control *wbc)
1896{
1897 struct fuse_inode *fi = get_fuse_inode(inode);
1898 struct fuse_file *ff;
1899 int err;
1900
1901 /*
1902 * Inode is always written before the last reference is dropped and
1903 * hence this should not be reached from reclaim.
1904 *
1905 * Writing back the inode from reclaim can deadlock if the request
1906 * processing itself needs an allocation. Allocations triggering
1907 * reclaim while serving a request can't be prevented, because it can
1908 * involve any number of unrelated userspace processes.
1909 */
1910 WARN_ON(wbc->for_reclaim);
1911
1912 ff = __fuse_write_file_get(fi);
1913 err = fuse_flush_times(inode, ff);
1914 if (ff)
1915 fuse_file_put(ff, false, false);
1916
1917 return err;
1918}
1919
1920static struct fuse_writepage_args *fuse_writepage_args_alloc(void)
1921{
1922 struct fuse_writepage_args *wpa;
1923 struct fuse_args_pages *ap;
1924
1925 wpa = kzalloc(sizeof(*wpa), GFP_NOFS);
1926 if (wpa) {
1927 ap = &wpa->ia.ap;
1928 ap->num_pages = 0;
1929 ap->pages = fuse_pages_alloc(1, GFP_NOFS, &ap->descs);
1930 if (!ap->pages) {
1931 kfree(wpa);
1932 wpa = NULL;
1933 }
1934 }
1935 return wpa;
1936
1937}
1938
1939static void fuse_writepage_add_to_bucket(struct fuse_conn *fc,
1940 struct fuse_writepage_args *wpa)
1941{
1942 if (!fc->sync_fs)
1943 return;
1944
1945 rcu_read_lock();
1946 /* Prevent resurrection of dead bucket in unlikely race with syncfs */
1947 do {
1948 wpa->bucket = rcu_dereference(fc->curr_bucket);
1949 } while (unlikely(!atomic_inc_not_zero(&wpa->bucket->count)));
1950 rcu_read_unlock();
1951}
1952
1953static int fuse_writepage_locked(struct page *page)
1954{
1955 struct address_space *mapping = page->mapping;
1956 struct inode *inode = mapping->host;
1957 struct fuse_conn *fc = get_fuse_conn(inode);
1958 struct fuse_inode *fi = get_fuse_inode(inode);
1959 struct fuse_writepage_args *wpa;
1960 struct fuse_args_pages *ap;
1961 struct page *tmp_page;
1962 int error = -ENOMEM;
1963
1964 set_page_writeback(page);
1965
1966 wpa = fuse_writepage_args_alloc();
1967 if (!wpa)
1968 goto err;
1969 ap = &wpa->ia.ap;
1970
1971 tmp_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
1972 if (!tmp_page)
1973 goto err_free;
1974
1975 error = -EIO;
1976 wpa->ia.ff = fuse_write_file_get(fi);
1977 if (!wpa->ia.ff)
1978 goto err_nofile;
1979
1980 fuse_writepage_add_to_bucket(fc, wpa);
1981 fuse_write_args_fill(&wpa->ia, wpa->ia.ff, page_offset(page), 0);
1982
1983 copy_highpage(tmp_page, page);
1984 wpa->ia.write.in.write_flags |= FUSE_WRITE_CACHE;
1985 wpa->next = NULL;
1986 ap->args.in_pages = true;
1987 ap->num_pages = 1;
1988 ap->pages[0] = tmp_page;
1989 ap->descs[0].offset = 0;
1990 ap->descs[0].length = PAGE_SIZE;
1991 ap->args.end = fuse_writepage_end;
1992 wpa->inode = inode;
1993
1994 inc_wb_stat(&inode_to_bdi(inode)->wb, WB_WRITEBACK);
1995 inc_node_page_state(tmp_page, NR_WRITEBACK_TEMP);
1996
1997 spin_lock(&fi->lock);
1998 tree_insert(&fi->writepages, wpa);
1999 list_add_tail(&wpa->queue_entry, &fi->queued_writes);
2000 fuse_flush_writepages(inode);
2001 spin_unlock(&fi->lock);
2002
2003 end_page_writeback(page);
2004
2005 return 0;
2006
2007err_nofile:
2008 __free_page(tmp_page);
2009err_free:
2010 kfree(wpa);
2011err:
2012 mapping_set_error(page->mapping, error);
2013 end_page_writeback(page);
2014 return error;
2015}
2016
2017static int fuse_writepage(struct page *page, struct writeback_control *wbc)
2018{
2019 struct fuse_conn *fc = get_fuse_conn(page->mapping->host);
2020 int err;
2021
2022 if (fuse_page_is_writeback(page->mapping->host, page->index)) {
2023 /*
2024 * ->writepages() should be called for sync() and friends. We
2025 * should only get here on direct reclaim and then we are
2026 * allowed to skip a page which is already in flight
2027 */
2028 WARN_ON(wbc->sync_mode == WB_SYNC_ALL);
2029
2030 redirty_page_for_writepage(wbc, page);
2031 unlock_page(page);
2032 return 0;
2033 }
2034
2035 if (wbc->sync_mode == WB_SYNC_NONE &&
2036 fc->num_background >= fc->congestion_threshold)
2037 return AOP_WRITEPAGE_ACTIVATE;
2038
2039 err = fuse_writepage_locked(page);
2040 unlock_page(page);
2041
2042 return err;
2043}
2044
2045struct fuse_fill_wb_data {
2046 struct fuse_writepage_args *wpa;
2047 struct fuse_file *ff;
2048 struct inode *inode;
2049 struct page **orig_pages;
2050 unsigned int max_pages;
2051};
2052
2053static bool fuse_pages_realloc(struct fuse_fill_wb_data *data)
2054{
2055 struct fuse_args_pages *ap = &data->wpa->ia.ap;
2056 struct fuse_conn *fc = get_fuse_conn(data->inode);
2057 struct page **pages;
2058 struct fuse_page_desc *descs;
2059 unsigned int npages = min_t(unsigned int,
2060 max_t(unsigned int, data->max_pages * 2,
2061 FUSE_DEFAULT_MAX_PAGES_PER_REQ),
2062 fc->max_pages);
2063 WARN_ON(npages <= data->max_pages);
2064
2065 pages = fuse_pages_alloc(npages, GFP_NOFS, &descs);
2066 if (!pages)
2067 return false;
2068
2069 memcpy(pages, ap->pages, sizeof(struct page *) * ap->num_pages);
2070 memcpy(descs, ap->descs, sizeof(struct fuse_page_desc) * ap->num_pages);
2071 kfree(ap->pages);
2072 ap->pages = pages;
2073 ap->descs = descs;
2074 data->max_pages = npages;
2075
2076 return true;
2077}
2078
2079static void fuse_writepages_send(struct fuse_fill_wb_data *data)
2080{
2081 struct fuse_writepage_args *wpa = data->wpa;
2082 struct inode *inode = data->inode;
2083 struct fuse_inode *fi = get_fuse_inode(inode);
2084 int num_pages = wpa->ia.ap.num_pages;
2085 int i;
2086
2087 wpa->ia.ff = fuse_file_get(data->ff);
2088 spin_lock(&fi->lock);
2089 list_add_tail(&wpa->queue_entry, &fi->queued_writes);
2090 fuse_flush_writepages(inode);
2091 spin_unlock(&fi->lock);
2092
2093 for (i = 0; i < num_pages; i++)
2094 end_page_writeback(data->orig_pages[i]);
2095}
2096
2097/*
2098 * Check under fi->lock if the page is under writeback, and insert it onto the
2099 * rb_tree if not. Otherwise iterate auxiliary write requests, to see if there's
2100 * one already added for a page at this offset. If there's none, then insert
2101 * this new request onto the auxiliary list, otherwise reuse the existing one by
2102 * swapping the new temp page with the old one.
2103 */
2104static bool fuse_writepage_add(struct fuse_writepage_args *new_wpa,
2105 struct page *page)
2106{
2107 struct fuse_inode *fi = get_fuse_inode(new_wpa->inode);
2108 struct fuse_writepage_args *tmp;
2109 struct fuse_writepage_args *old_wpa;
2110 struct fuse_args_pages *new_ap = &new_wpa->ia.ap;
2111
2112 WARN_ON(new_ap->num_pages != 0);
2113 new_ap->num_pages = 1;
2114
2115 spin_lock(&fi->lock);
2116 old_wpa = fuse_insert_writeback(&fi->writepages, new_wpa);
2117 if (!old_wpa) {
2118 spin_unlock(&fi->lock);
2119 return true;
2120 }
2121
2122 for (tmp = old_wpa->next; tmp; tmp = tmp->next) {
2123 pgoff_t curr_index;
2124
2125 WARN_ON(tmp->inode != new_wpa->inode);
2126 curr_index = tmp->ia.write.in.offset >> PAGE_SHIFT;
2127 if (curr_index == page->index) {
2128 WARN_ON(tmp->ia.ap.num_pages != 1);
2129 swap(tmp->ia.ap.pages[0], new_ap->pages[0]);
2130 break;
2131 }
2132 }
2133
2134 if (!tmp) {
2135 new_wpa->next = old_wpa->next;
2136 old_wpa->next = new_wpa;
2137 }
2138
2139 spin_unlock(&fi->lock);
2140
2141 if (tmp) {
2142 struct backing_dev_info *bdi = inode_to_bdi(new_wpa->inode);
2143
2144 dec_wb_stat(&bdi->wb, WB_WRITEBACK);
2145 dec_node_page_state(new_ap->pages[0], NR_WRITEBACK_TEMP);
2146 wb_writeout_inc(&bdi->wb);
2147 fuse_writepage_free(new_wpa);
2148 }
2149
2150 return false;
2151}
2152
2153static bool fuse_writepage_need_send(struct fuse_conn *fc, struct page *page,
2154 struct fuse_args_pages *ap,
2155 struct fuse_fill_wb_data *data)
2156{
2157 WARN_ON(!ap->num_pages);
2158
2159 /*
2160 * Being under writeback is unlikely but possible. For example direct
2161 * read to an mmaped fuse file will set the page dirty twice; once when
2162 * the pages are faulted with get_user_pages(), and then after the read
2163 * completed.
2164 */
2165 if (fuse_page_is_writeback(data->inode, page->index))
2166 return true;
2167
2168 /* Reached max pages */
2169 if (ap->num_pages == fc->max_pages)
2170 return true;
2171
2172 /* Reached max write bytes */
2173 if ((ap->num_pages + 1) * PAGE_SIZE > fc->max_write)
2174 return true;
2175
2176 /* Discontinuity */
2177 if (data->orig_pages[ap->num_pages - 1]->index + 1 != page->index)
2178 return true;
2179
2180 /* Need to grow the pages array? If so, did the expansion fail? */
2181 if (ap->num_pages == data->max_pages && !fuse_pages_realloc(data))
2182 return true;
2183
2184 return false;
2185}
2186
2187static int fuse_writepages_fill(struct page *page,
2188 struct writeback_control *wbc, void *_data)
2189{
2190 struct fuse_fill_wb_data *data = _data;
2191 struct fuse_writepage_args *wpa = data->wpa;
2192 struct fuse_args_pages *ap = &wpa->ia.ap;
2193 struct inode *inode = data->inode;
2194 struct fuse_inode *fi = get_fuse_inode(inode);
2195 struct fuse_conn *fc = get_fuse_conn(inode);
2196 struct page *tmp_page;
2197 int err;
2198
2199 if (!data->ff) {
2200 err = -EIO;
2201 data->ff = fuse_write_file_get(fi);
2202 if (!data->ff)
2203 goto out_unlock;
2204 }
2205
2206 if (wpa && fuse_writepage_need_send(fc, page, ap, data)) {
2207 fuse_writepages_send(data);
2208 data->wpa = NULL;
2209 }
2210
2211 err = -ENOMEM;
2212 tmp_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
2213 if (!tmp_page)
2214 goto out_unlock;
2215
2216 /*
2217 * The page must not be redirtied until the writeout is completed
2218 * (i.e. userspace has sent a reply to the write request). Otherwise
2219 * there could be more than one temporary page instance for each real
2220 * page.
2221 *
2222 * This is ensured by holding the page lock in page_mkwrite() while
2223 * checking fuse_page_is_writeback(). We already hold the page lock
2224 * since clear_page_dirty_for_io() and keep it held until we add the
2225 * request to the fi->writepages list and increment ap->num_pages.
2226 * After this fuse_page_is_writeback() will indicate that the page is
2227 * under writeback, so we can release the page lock.
2228 */
2229 if (data->wpa == NULL) {
2230 err = -ENOMEM;
2231 wpa = fuse_writepage_args_alloc();
2232 if (!wpa) {
2233 __free_page(tmp_page);
2234 goto out_unlock;
2235 }
2236 fuse_writepage_add_to_bucket(fc, wpa);
2237
2238 data->max_pages = 1;
2239
2240 ap = &wpa->ia.ap;
2241 fuse_write_args_fill(&wpa->ia, data->ff, page_offset(page), 0);
2242 wpa->ia.write.in.write_flags |= FUSE_WRITE_CACHE;
2243 wpa->next = NULL;
2244 ap->args.in_pages = true;
2245 ap->args.end = fuse_writepage_end;
2246 ap->num_pages = 0;
2247 wpa->inode = inode;
2248 }
2249 set_page_writeback(page);
2250
2251 copy_highpage(tmp_page, page);
2252 ap->pages[ap->num_pages] = tmp_page;
2253 ap->descs[ap->num_pages].offset = 0;
2254 ap->descs[ap->num_pages].length = PAGE_SIZE;
2255 data->orig_pages[ap->num_pages] = page;
2256
2257 inc_wb_stat(&inode_to_bdi(inode)->wb, WB_WRITEBACK);
2258 inc_node_page_state(tmp_page, NR_WRITEBACK_TEMP);
2259
2260 err = 0;
2261 if (data->wpa) {
2262 /*
2263 * Protected by fi->lock against concurrent access by
2264 * fuse_page_is_writeback().
2265 */
2266 spin_lock(&fi->lock);
2267 ap->num_pages++;
2268 spin_unlock(&fi->lock);
2269 } else if (fuse_writepage_add(wpa, page)) {
2270 data->wpa = wpa;
2271 } else {
2272 end_page_writeback(page);
2273 }
2274out_unlock:
2275 unlock_page(page);
2276
2277 return err;
2278}
2279
2280static int fuse_writepages(struct address_space *mapping,
2281 struct writeback_control *wbc)
2282{
2283 struct inode *inode = mapping->host;
2284 struct fuse_conn *fc = get_fuse_conn(inode);
2285 struct fuse_fill_wb_data data;
2286 int err;
2287
2288 err = -EIO;
2289 if (fuse_is_bad(inode))
2290 goto out;
2291
2292 if (wbc->sync_mode == WB_SYNC_NONE &&
2293 fc->num_background >= fc->congestion_threshold)
2294 return 0;
2295
2296 data.inode = inode;
2297 data.wpa = NULL;
2298 data.ff = NULL;
2299
2300 err = -ENOMEM;
2301 data.orig_pages = kcalloc(fc->max_pages,
2302 sizeof(struct page *),
2303 GFP_NOFS);
2304 if (!data.orig_pages)
2305 goto out;
2306
2307 err = write_cache_pages(mapping, wbc, fuse_writepages_fill, &data);
2308 if (data.wpa) {
2309 WARN_ON(!data.wpa->ia.ap.num_pages);
2310 fuse_writepages_send(&data);
2311 }
2312 if (data.ff)
2313 fuse_file_put(data.ff, false, false);
2314
2315 kfree(data.orig_pages);
2316out:
2317 return err;
2318}
2319
2320/*
2321 * It's worthy to make sure that space is reserved on disk for the write,
2322 * but how to implement it without killing performance need more thinking.
2323 */
2324static int fuse_write_begin(struct file *file, struct address_space *mapping,
2325 loff_t pos, unsigned len, struct page **pagep, void **fsdata)
2326{
2327 pgoff_t index = pos >> PAGE_SHIFT;
2328 struct fuse_conn *fc = get_fuse_conn(file_inode(file));
2329 struct page *page;
2330 loff_t fsize;
2331 int err = -ENOMEM;
2332
2333 WARN_ON(!fc->writeback_cache);
2334
2335 page = grab_cache_page_write_begin(mapping, index);
2336 if (!page)
2337 goto error;
2338
2339 fuse_wait_on_page_writeback(mapping->host, page->index);
2340
2341 if (PageUptodate(page) || len == PAGE_SIZE)
2342 goto success;
2343 /*
2344 * Check if the start this page comes after the end of file, in which
2345 * case the readpage can be optimized away.
2346 */
2347 fsize = i_size_read(mapping->host);
2348 if (fsize <= (pos & PAGE_MASK)) {
2349 size_t off = pos & ~PAGE_MASK;
2350 if (off)
2351 zero_user_segment(page, 0, off);
2352 goto success;
2353 }
2354 err = fuse_do_readpage(file, page);
2355 if (err)
2356 goto cleanup;
2357success:
2358 *pagep = page;
2359 return 0;
2360
2361cleanup:
2362 unlock_page(page);
2363 put_page(page);
2364error:
2365 return err;
2366}
2367
2368static int fuse_write_end(struct file *file, struct address_space *mapping,
2369 loff_t pos, unsigned len, unsigned copied,
2370 struct page *page, void *fsdata)
2371{
2372 struct inode *inode = page->mapping->host;
2373
2374 /* Haven't copied anything? Skip zeroing, size extending, dirtying. */
2375 if (!copied)
2376 goto unlock;
2377
2378 pos += copied;
2379 if (!PageUptodate(page)) {
2380 /* Zero any unwritten bytes at the end of the page */
2381 size_t endoff = pos & ~PAGE_MASK;
2382 if (endoff)
2383 zero_user_segment(page, endoff, PAGE_SIZE);
2384 SetPageUptodate(page);
2385 }
2386
2387 if (pos > inode->i_size)
2388 i_size_write(inode, pos);
2389
2390 set_page_dirty(page);
2391
2392unlock:
2393 unlock_page(page);
2394 put_page(page);
2395
2396 return copied;
2397}
2398
2399static int fuse_launder_folio(struct folio *folio)
2400{
2401 int err = 0;
2402 if (folio_clear_dirty_for_io(folio)) {
2403 struct inode *inode = folio->mapping->host;
2404
2405 /* Serialize with pending writeback for the same page */
2406 fuse_wait_on_page_writeback(inode, folio->index);
2407 err = fuse_writepage_locked(&folio->page);
2408 if (!err)
2409 fuse_wait_on_page_writeback(inode, folio->index);
2410 }
2411 return err;
2412}
2413
2414/*
2415 * Write back dirty data/metadata now (there may not be any suitable
2416 * open files later for data)
2417 */
2418static void fuse_vma_close(struct vm_area_struct *vma)
2419{
2420 int err;
2421
2422 err = write_inode_now(vma->vm_file->f_mapping->host, 1);
2423 mapping_set_error(vma->vm_file->f_mapping, err);
2424}
2425
2426/*
2427 * Wait for writeback against this page to complete before allowing it
2428 * to be marked dirty again, and hence written back again, possibly
2429 * before the previous writepage completed.
2430 *
2431 * Block here, instead of in ->writepage(), so that the userspace fs
2432 * can only block processes actually operating on the filesystem.
2433 *
2434 * Otherwise unprivileged userspace fs would be able to block
2435 * unrelated:
2436 *
2437 * - page migration
2438 * - sync(2)
2439 * - try_to_free_pages() with order > PAGE_ALLOC_COSTLY_ORDER
2440 */
2441static vm_fault_t fuse_page_mkwrite(struct vm_fault *vmf)
2442{
2443 struct page *page = vmf->page;
2444 struct inode *inode = file_inode(vmf->vma->vm_file);
2445
2446 file_update_time(vmf->vma->vm_file);
2447 lock_page(page);
2448 if (page->mapping != inode->i_mapping) {
2449 unlock_page(page);
2450 return VM_FAULT_NOPAGE;
2451 }
2452
2453 fuse_wait_on_page_writeback(inode, page->index);
2454 return VM_FAULT_LOCKED;
2455}
2456
2457static const struct vm_operations_struct fuse_file_vm_ops = {
2458 .close = fuse_vma_close,
2459 .fault = filemap_fault,
2460 .map_pages = filemap_map_pages,
2461 .page_mkwrite = fuse_page_mkwrite,
2462};
2463
2464static int fuse_file_mmap(struct file *file, struct vm_area_struct *vma)
2465{
2466 struct fuse_file *ff = file->private_data;
2467
2468 /* DAX mmap is superior to direct_io mmap */
2469 if (FUSE_IS_DAX(file_inode(file)))
2470 return fuse_dax_mmap(file, vma);
2471
2472 if (ff->open_flags & FOPEN_DIRECT_IO) {
2473 /* Can't provide the coherency needed for MAP_SHARED */
2474 if (vma->vm_flags & VM_MAYSHARE)
2475 return -ENODEV;
2476
2477 invalidate_inode_pages2(file->f_mapping);
2478
2479 return generic_file_mmap(file, vma);
2480 }
2481
2482 if ((vma->vm_flags & VM_SHARED) && (vma->vm_flags & VM_MAYWRITE))
2483 fuse_link_write_file(file);
2484
2485 file_accessed(file);
2486 vma->vm_ops = &fuse_file_vm_ops;
2487 return 0;
2488}
2489
2490static int convert_fuse_file_lock(struct fuse_conn *fc,
2491 const struct fuse_file_lock *ffl,
2492 struct file_lock *fl)
2493{
2494 switch (ffl->type) {
2495 case F_UNLCK:
2496 break;
2497
2498 case F_RDLCK:
2499 case F_WRLCK:
2500 if (ffl->start > OFFSET_MAX || ffl->end > OFFSET_MAX ||
2501 ffl->end < ffl->start)
2502 return -EIO;
2503
2504 fl->fl_start = ffl->start;
2505 fl->fl_end = ffl->end;
2506
2507 /*
2508 * Convert pid into init's pid namespace. The locks API will
2509 * translate it into the caller's pid namespace.
2510 */
2511 rcu_read_lock();
2512 fl->fl_pid = pid_nr_ns(find_pid_ns(ffl->pid, fc->pid_ns), &init_pid_ns);
2513 rcu_read_unlock();
2514 break;
2515
2516 default:
2517 return -EIO;
2518 }
2519 fl->fl_type = ffl->type;
2520 return 0;
2521}
2522
2523static void fuse_lk_fill(struct fuse_args *args, struct file *file,
2524 const struct file_lock *fl, int opcode, pid_t pid,
2525 int flock, struct fuse_lk_in *inarg)
2526{
2527 struct inode *inode = file_inode(file);
2528 struct fuse_conn *fc = get_fuse_conn(inode);
2529 struct fuse_file *ff = file->private_data;
2530
2531 memset(inarg, 0, sizeof(*inarg));
2532 inarg->fh = ff->fh;
2533 inarg->owner = fuse_lock_owner_id(fc, fl->fl_owner);
2534 inarg->lk.start = fl->fl_start;
2535 inarg->lk.end = fl->fl_end;
2536 inarg->lk.type = fl->fl_type;
2537 inarg->lk.pid = pid;
2538 if (flock)
2539 inarg->lk_flags |= FUSE_LK_FLOCK;
2540 args->opcode = opcode;
2541 args->nodeid = get_node_id(inode);
2542 args->in_numargs = 1;
2543 args->in_args[0].size = sizeof(*inarg);
2544 args->in_args[0].value = inarg;
2545}
2546
2547static int fuse_getlk(struct file *file, struct file_lock *fl)
2548{
2549 struct inode *inode = file_inode(file);
2550 struct fuse_mount *fm = get_fuse_mount(inode);
2551 FUSE_ARGS(args);
2552 struct fuse_lk_in inarg;
2553 struct fuse_lk_out outarg;
2554 int err;
2555
2556 fuse_lk_fill(&args, file, fl, FUSE_GETLK, 0, 0, &inarg);
2557 args.out_numargs = 1;
2558 args.out_args[0].size = sizeof(outarg);
2559 args.out_args[0].value = &outarg;
2560 err = fuse_simple_request(fm, &args);
2561 if (!err)
2562 err = convert_fuse_file_lock(fm->fc, &outarg.lk, fl);
2563
2564 return err;
2565}
2566
2567static int fuse_setlk(struct file *file, struct file_lock *fl, int flock)
2568{
2569 struct inode *inode = file_inode(file);
2570 struct fuse_mount *fm = get_fuse_mount(inode);
2571 FUSE_ARGS(args);
2572 struct fuse_lk_in inarg;
2573 int opcode = (fl->fl_flags & FL_SLEEP) ? FUSE_SETLKW : FUSE_SETLK;
2574 struct pid *pid = fl->fl_type != F_UNLCK ? task_tgid(current) : NULL;
2575 pid_t pid_nr = pid_nr_ns(pid, fm->fc->pid_ns);
2576 int err;
2577
2578 if (fl->fl_lmops && fl->fl_lmops->lm_grant) {
2579 /* NLM needs asynchronous locks, which we don't support yet */
2580 return -ENOLCK;
2581 }
2582
2583 /* Unlock on close is handled by the flush method */
2584 if ((fl->fl_flags & FL_CLOSE_POSIX) == FL_CLOSE_POSIX)
2585 return 0;
2586
2587 fuse_lk_fill(&args, file, fl, opcode, pid_nr, flock, &inarg);
2588 err = fuse_simple_request(fm, &args);
2589
2590 /* locking is restartable */
2591 if (err == -EINTR)
2592 err = -ERESTARTSYS;
2593
2594 return err;
2595}
2596
2597static int fuse_file_lock(struct file *file, int cmd, struct file_lock *fl)
2598{
2599 struct inode *inode = file_inode(file);
2600 struct fuse_conn *fc = get_fuse_conn(inode);
2601 int err;
2602
2603 if (cmd == F_CANCELLK) {
2604 err = 0;
2605 } else if (cmd == F_GETLK) {
2606 if (fc->no_lock) {
2607 posix_test_lock(file, fl);
2608 err = 0;
2609 } else
2610 err = fuse_getlk(file, fl);
2611 } else {
2612 if (fc->no_lock)
2613 err = posix_lock_file(file, fl, NULL);
2614 else
2615 err = fuse_setlk(file, fl, 0);
2616 }
2617 return err;
2618}
2619
2620static int fuse_file_flock(struct file *file, int cmd, struct file_lock *fl)
2621{
2622 struct inode *inode = file_inode(file);
2623 struct fuse_conn *fc = get_fuse_conn(inode);
2624 int err;
2625
2626 if (fc->no_flock) {
2627 err = locks_lock_file_wait(file, fl);
2628 } else {
2629 struct fuse_file *ff = file->private_data;
2630
2631 /* emulate flock with POSIX locks */
2632 ff->flock = true;
2633 err = fuse_setlk(file, fl, 1);
2634 }
2635
2636 return err;
2637}
2638
2639static sector_t fuse_bmap(struct address_space *mapping, sector_t block)
2640{
2641 struct inode *inode = mapping->host;
2642 struct fuse_mount *fm = get_fuse_mount(inode);
2643 FUSE_ARGS(args);
2644 struct fuse_bmap_in inarg;
2645 struct fuse_bmap_out outarg;
2646 int err;
2647
2648 if (!inode->i_sb->s_bdev || fm->fc->no_bmap)
2649 return 0;
2650
2651 memset(&inarg, 0, sizeof(inarg));
2652 inarg.block = block;
2653 inarg.blocksize = inode->i_sb->s_blocksize;
2654 args.opcode = FUSE_BMAP;
2655 args.nodeid = get_node_id(inode);
2656 args.in_numargs = 1;
2657 args.in_args[0].size = sizeof(inarg);
2658 args.in_args[0].value = &inarg;
2659 args.out_numargs = 1;
2660 args.out_args[0].size = sizeof(outarg);
2661 args.out_args[0].value = &outarg;
2662 err = fuse_simple_request(fm, &args);
2663 if (err == -ENOSYS)
2664 fm->fc->no_bmap = 1;
2665
2666 return err ? 0 : outarg.block;
2667}
2668
2669static loff_t fuse_lseek(struct file *file, loff_t offset, int whence)
2670{
2671 struct inode *inode = file->f_mapping->host;
2672 struct fuse_mount *fm = get_fuse_mount(inode);
2673 struct fuse_file *ff = file->private_data;
2674 FUSE_ARGS(args);
2675 struct fuse_lseek_in inarg = {
2676 .fh = ff->fh,
2677 .offset = offset,
2678 .whence = whence
2679 };
2680 struct fuse_lseek_out outarg;
2681 int err;
2682
2683 if (fm->fc->no_lseek)
2684 goto fallback;
2685
2686 args.opcode = FUSE_LSEEK;
2687 args.nodeid = ff->nodeid;
2688 args.in_numargs = 1;
2689 args.in_args[0].size = sizeof(inarg);
2690 args.in_args[0].value = &inarg;
2691 args.out_numargs = 1;
2692 args.out_args[0].size = sizeof(outarg);
2693 args.out_args[0].value = &outarg;
2694 err = fuse_simple_request(fm, &args);
2695 if (err) {
2696 if (err == -ENOSYS) {
2697 fm->fc->no_lseek = 1;
2698 goto fallback;
2699 }
2700 return err;
2701 }
2702
2703 return vfs_setpos(file, outarg.offset, inode->i_sb->s_maxbytes);
2704
2705fallback:
2706 err = fuse_update_attributes(inode, file, STATX_SIZE);
2707 if (!err)
2708 return generic_file_llseek(file, offset, whence);
2709 else
2710 return err;
2711}
2712
2713static loff_t fuse_file_llseek(struct file *file, loff_t offset, int whence)
2714{
2715 loff_t retval;
2716 struct inode *inode = file_inode(file);
2717
2718 switch (whence) {
2719 case SEEK_SET:
2720 case SEEK_CUR:
2721 /* No i_mutex protection necessary for SEEK_CUR and SEEK_SET */
2722 retval = generic_file_llseek(file, offset, whence);
2723 break;
2724 case SEEK_END:
2725 inode_lock(inode);
2726 retval = fuse_update_attributes(inode, file, STATX_SIZE);
2727 if (!retval)
2728 retval = generic_file_llseek(file, offset, whence);
2729 inode_unlock(inode);
2730 break;
2731 case SEEK_HOLE:
2732 case SEEK_DATA:
2733 inode_lock(inode);
2734 retval = fuse_lseek(file, offset, whence);
2735 inode_unlock(inode);
2736 break;
2737 default:
2738 retval = -EINVAL;
2739 }
2740
2741 return retval;
2742}
2743
2744/*
2745 * All files which have been polled are linked to RB tree
2746 * fuse_conn->polled_files which is indexed by kh. Walk the tree and
2747 * find the matching one.
2748 */
2749static struct rb_node **fuse_find_polled_node(struct fuse_conn *fc, u64 kh,
2750 struct rb_node **parent_out)
2751{
2752 struct rb_node **link = &fc->polled_files.rb_node;
2753 struct rb_node *last = NULL;
2754
2755 while (*link) {
2756 struct fuse_file *ff;
2757
2758 last = *link;
2759 ff = rb_entry(last, struct fuse_file, polled_node);
2760
2761 if (kh < ff->kh)
2762 link = &last->rb_left;
2763 else if (kh > ff->kh)
2764 link = &last->rb_right;
2765 else
2766 return link;
2767 }
2768
2769 if (parent_out)
2770 *parent_out = last;
2771 return link;
2772}
2773
2774/*
2775 * The file is about to be polled. Make sure it's on the polled_files
2776 * RB tree. Note that files once added to the polled_files tree are
2777 * not removed before the file is released. This is because a file
2778 * polled once is likely to be polled again.
2779 */
2780static void fuse_register_polled_file(struct fuse_conn *fc,
2781 struct fuse_file *ff)
2782{
2783 spin_lock(&fc->lock);
2784 if (RB_EMPTY_NODE(&ff->polled_node)) {
2785 struct rb_node **link, *parent;
2786
2787 link = fuse_find_polled_node(fc, ff->kh, &parent);
2788 BUG_ON(*link);
2789 rb_link_node(&ff->polled_node, parent, link);
2790 rb_insert_color(&ff->polled_node, &fc->polled_files);
2791 }
2792 spin_unlock(&fc->lock);
2793}
2794
2795__poll_t fuse_file_poll(struct file *file, poll_table *wait)
2796{
2797 struct fuse_file *ff = file->private_data;
2798 struct fuse_mount *fm = ff->fm;
2799 struct fuse_poll_in inarg = { .fh = ff->fh, .kh = ff->kh };
2800 struct fuse_poll_out outarg;
2801 FUSE_ARGS(args);
2802 int err;
2803
2804 if (fm->fc->no_poll)
2805 return DEFAULT_POLLMASK;
2806
2807 poll_wait(file, &ff->poll_wait, wait);
2808 inarg.events = mangle_poll(poll_requested_events(wait));
2809
2810 /*
2811 * Ask for notification iff there's someone waiting for it.
2812 * The client may ignore the flag and always notify.
2813 */
2814 if (waitqueue_active(&ff->poll_wait)) {
2815 inarg.flags |= FUSE_POLL_SCHEDULE_NOTIFY;
2816 fuse_register_polled_file(fm->fc, ff);
2817 }
2818
2819 args.opcode = FUSE_POLL;
2820 args.nodeid = ff->nodeid;
2821 args.in_numargs = 1;
2822 args.in_args[0].size = sizeof(inarg);
2823 args.in_args[0].value = &inarg;
2824 args.out_numargs = 1;
2825 args.out_args[0].size = sizeof(outarg);
2826 args.out_args[0].value = &outarg;
2827 err = fuse_simple_request(fm, &args);
2828
2829 if (!err)
2830 return demangle_poll(outarg.revents);
2831 if (err == -ENOSYS) {
2832 fm->fc->no_poll = 1;
2833 return DEFAULT_POLLMASK;
2834 }
2835 return EPOLLERR;
2836}
2837EXPORT_SYMBOL_GPL(fuse_file_poll);
2838
2839/*
2840 * This is called from fuse_handle_notify() on FUSE_NOTIFY_POLL and
2841 * wakes up the poll waiters.
2842 */
2843int fuse_notify_poll_wakeup(struct fuse_conn *fc,
2844 struct fuse_notify_poll_wakeup_out *outarg)
2845{
2846 u64 kh = outarg->kh;
2847 struct rb_node **link;
2848
2849 spin_lock(&fc->lock);
2850
2851 link = fuse_find_polled_node(fc, kh, NULL);
2852 if (*link) {
2853 struct fuse_file *ff;
2854
2855 ff = rb_entry(*link, struct fuse_file, polled_node);
2856 wake_up_interruptible_sync(&ff->poll_wait);
2857 }
2858
2859 spin_unlock(&fc->lock);
2860 return 0;
2861}
2862
2863static void fuse_do_truncate(struct file *file)
2864{
2865 struct inode *inode = file->f_mapping->host;
2866 struct iattr attr;
2867
2868 attr.ia_valid = ATTR_SIZE;
2869 attr.ia_size = i_size_read(inode);
2870
2871 attr.ia_file = file;
2872 attr.ia_valid |= ATTR_FILE;
2873
2874 fuse_do_setattr(file_dentry(file), &attr, file);
2875}
2876
2877static inline loff_t fuse_round_up(struct fuse_conn *fc, loff_t off)
2878{
2879 return round_up(off, fc->max_pages << PAGE_SHIFT);
2880}
2881
2882static ssize_t
2883fuse_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
2884{
2885 DECLARE_COMPLETION_ONSTACK(wait);
2886 ssize_t ret = 0;
2887 struct file *file = iocb->ki_filp;
2888 struct fuse_file *ff = file->private_data;
2889 loff_t pos = 0;
2890 struct inode *inode;
2891 loff_t i_size;
2892 size_t count = iov_iter_count(iter), shortened = 0;
2893 loff_t offset = iocb->ki_pos;
2894 struct fuse_io_priv *io;
2895
2896 pos = offset;
2897 inode = file->f_mapping->host;
2898 i_size = i_size_read(inode);
2899
2900 if ((iov_iter_rw(iter) == READ) && (offset >= i_size))
2901 return 0;
2902
2903 io = kmalloc(sizeof(struct fuse_io_priv), GFP_KERNEL);
2904 if (!io)
2905 return -ENOMEM;
2906 spin_lock_init(&io->lock);
2907 kref_init(&io->refcnt);
2908 io->reqs = 1;
2909 io->bytes = -1;
2910 io->size = 0;
2911 io->offset = offset;
2912 io->write = (iov_iter_rw(iter) == WRITE);
2913 io->err = 0;
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 = ff->fm->fc->async_dio;
2919 io->iocb = iocb;
2920 io->blocking = is_sync_kiocb(iocb);
2921
2922 /* optimization for short read */
2923 if (io->async && !io->write && offset + count > i_size) {
2924 iov_iter_truncate(iter, fuse_round_up(ff->fm->fc, i_size - offset));
2925 shortened = count - iov_iter_count(iter);
2926 count -= shortened;
2927 }
2928
2929 /*
2930 * We cannot asynchronously extend the size of a file.
2931 * In such case the aio will behave exactly like sync io.
2932 */
2933 if ((offset + count > i_size) && io->write)
2934 io->blocking = true;
2935
2936 if (io->async && io->blocking) {
2937 /*
2938 * Additional reference to keep io around after
2939 * calling fuse_aio_complete()
2940 */
2941 kref_get(&io->refcnt);
2942 io->done = &wait;
2943 }
2944
2945 if (iov_iter_rw(iter) == WRITE) {
2946 ret = fuse_direct_io(io, iter, &pos, FUSE_DIO_WRITE);
2947 fuse_invalidate_attr_mask(inode, FUSE_STATX_MODSIZE);
2948 } else {
2949 ret = __fuse_direct_read(io, iter, &pos);
2950 }
2951 iov_iter_reexpand(iter, iov_iter_count(iter) + shortened);
2952
2953 if (io->async) {
2954 bool blocking = io->blocking;
2955
2956 fuse_aio_complete(io, ret < 0 ? ret : 0, -1);
2957
2958 /* we have a non-extending, async request, so return */
2959 if (!blocking)
2960 return -EIOCBQUEUED;
2961
2962 wait_for_completion(&wait);
2963 ret = fuse_get_res_by_io(io);
2964 }
2965
2966 kref_put(&io->refcnt, fuse_io_release);
2967
2968 if (iov_iter_rw(iter) == WRITE) {
2969 fuse_write_update_attr(inode, pos, ret);
2970 /* For extending writes we already hold exclusive lock */
2971 if (ret < 0 && offset + count > i_size)
2972 fuse_do_truncate(file);
2973 }
2974
2975 return ret;
2976}
2977
2978static int fuse_writeback_range(struct inode *inode, loff_t start, loff_t end)
2979{
2980 int err = filemap_write_and_wait_range(inode->i_mapping, start, LLONG_MAX);
2981
2982 if (!err)
2983 fuse_sync_writes(inode);
2984
2985 return err;
2986}
2987
2988static long fuse_file_fallocate(struct file *file, int mode, loff_t offset,
2989 loff_t length)
2990{
2991 struct fuse_file *ff = file->private_data;
2992 struct inode *inode = file_inode(file);
2993 struct fuse_inode *fi = get_fuse_inode(inode);
2994 struct fuse_mount *fm = ff->fm;
2995 FUSE_ARGS(args);
2996 struct fuse_fallocate_in inarg = {
2997 .fh = ff->fh,
2998 .offset = offset,
2999 .length = length,
3000 .mode = mode
3001 };
3002 int err;
3003 bool block_faults = FUSE_IS_DAX(inode) &&
3004 (!(mode & FALLOC_FL_KEEP_SIZE) ||
3005 (mode & (FALLOC_FL_PUNCH_HOLE | FALLOC_FL_ZERO_RANGE)));
3006
3007 if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE |
3008 FALLOC_FL_ZERO_RANGE))
3009 return -EOPNOTSUPP;
3010
3011 if (fm->fc->no_fallocate)
3012 return -EOPNOTSUPP;
3013
3014 inode_lock(inode);
3015 if (block_faults) {
3016 filemap_invalidate_lock(inode->i_mapping);
3017 err = fuse_dax_break_layouts(inode, 0, 0);
3018 if (err)
3019 goto out;
3020 }
3021
3022 if (mode & (FALLOC_FL_PUNCH_HOLE | FALLOC_FL_ZERO_RANGE)) {
3023 loff_t endbyte = offset + length - 1;
3024
3025 err = fuse_writeback_range(inode, offset, endbyte);
3026 if (err)
3027 goto out;
3028 }
3029
3030 if (!(mode & FALLOC_FL_KEEP_SIZE) &&
3031 offset + length > i_size_read(inode)) {
3032 err = inode_newsize_ok(inode, offset + length);
3033 if (err)
3034 goto out;
3035 }
3036
3037 err = file_modified(file);
3038 if (err)
3039 goto out;
3040
3041 if (!(mode & FALLOC_FL_KEEP_SIZE))
3042 set_bit(FUSE_I_SIZE_UNSTABLE, &fi->state);
3043
3044 args.opcode = FUSE_FALLOCATE;
3045 args.nodeid = ff->nodeid;
3046 args.in_numargs = 1;
3047 args.in_args[0].size = sizeof(inarg);
3048 args.in_args[0].value = &inarg;
3049 err = fuse_simple_request(fm, &args);
3050 if (err == -ENOSYS) {
3051 fm->fc->no_fallocate = 1;
3052 err = -EOPNOTSUPP;
3053 }
3054 if (err)
3055 goto out;
3056
3057 /* we could have extended the file */
3058 if (!(mode & FALLOC_FL_KEEP_SIZE)) {
3059 if (fuse_write_update_attr(inode, offset + length, length))
3060 file_update_time(file);
3061 }
3062
3063 if (mode & (FALLOC_FL_PUNCH_HOLE | FALLOC_FL_ZERO_RANGE))
3064 truncate_pagecache_range(inode, offset, offset + length - 1);
3065
3066 fuse_invalidate_attr_mask(inode, FUSE_STATX_MODSIZE);
3067
3068out:
3069 if (!(mode & FALLOC_FL_KEEP_SIZE))
3070 clear_bit(FUSE_I_SIZE_UNSTABLE, &fi->state);
3071
3072 if (block_faults)
3073 filemap_invalidate_unlock(inode->i_mapping);
3074
3075 inode_unlock(inode);
3076
3077 fuse_flush_time_update(inode);
3078
3079 return err;
3080}
3081
3082static ssize_t __fuse_copy_file_range(struct file *file_in, loff_t pos_in,
3083 struct file *file_out, loff_t pos_out,
3084 size_t len, unsigned int flags)
3085{
3086 struct fuse_file *ff_in = file_in->private_data;
3087 struct fuse_file *ff_out = file_out->private_data;
3088 struct inode *inode_in = file_inode(file_in);
3089 struct inode *inode_out = file_inode(file_out);
3090 struct fuse_inode *fi_out = get_fuse_inode(inode_out);
3091 struct fuse_mount *fm = ff_in->fm;
3092 struct fuse_conn *fc = fm->fc;
3093 FUSE_ARGS(args);
3094 struct fuse_copy_file_range_in inarg = {
3095 .fh_in = ff_in->fh,
3096 .off_in = pos_in,
3097 .nodeid_out = ff_out->nodeid,
3098 .fh_out = ff_out->fh,
3099 .off_out = pos_out,
3100 .len = len,
3101 .flags = flags
3102 };
3103 struct fuse_write_out outarg;
3104 ssize_t err;
3105 /* mark unstable when write-back is not used, and file_out gets
3106 * extended */
3107 bool is_unstable = (!fc->writeback_cache) &&
3108 ((pos_out + len) > inode_out->i_size);
3109
3110 if (fc->no_copy_file_range)
3111 return -EOPNOTSUPP;
3112
3113 if (file_inode(file_in)->i_sb != file_inode(file_out)->i_sb)
3114 return -EXDEV;
3115
3116 inode_lock(inode_in);
3117 err = fuse_writeback_range(inode_in, pos_in, pos_in + len - 1);
3118 inode_unlock(inode_in);
3119 if (err)
3120 return err;
3121
3122 inode_lock(inode_out);
3123
3124 err = file_modified(file_out);
3125 if (err)
3126 goto out;
3127
3128 /*
3129 * Write out dirty pages in the destination file before sending the COPY
3130 * request to userspace. After the request is completed, truncate off
3131 * pages (including partial ones) from the cache that have been copied,
3132 * since these contain stale data at that point.
3133 *
3134 * This should be mostly correct, but if the COPY writes to partial
3135 * pages (at the start or end) and the parts not covered by the COPY are
3136 * written through a memory map after calling fuse_writeback_range(),
3137 * then these partial page modifications will be lost on truncation.
3138 *
3139 * It is unlikely that someone would rely on such mixed style
3140 * modifications. Yet this does give less guarantees than if the
3141 * copying was performed with write(2).
3142 *
3143 * To fix this a mapping->invalidate_lock could be used to prevent new
3144 * faults while the copy is ongoing.
3145 */
3146 err = fuse_writeback_range(inode_out, pos_out, pos_out + len - 1);
3147 if (err)
3148 goto out;
3149
3150 if (is_unstable)
3151 set_bit(FUSE_I_SIZE_UNSTABLE, &fi_out->state);
3152
3153 args.opcode = FUSE_COPY_FILE_RANGE;
3154 args.nodeid = ff_in->nodeid;
3155 args.in_numargs = 1;
3156 args.in_args[0].size = sizeof(inarg);
3157 args.in_args[0].value = &inarg;
3158 args.out_numargs = 1;
3159 args.out_args[0].size = sizeof(outarg);
3160 args.out_args[0].value = &outarg;
3161 err = fuse_simple_request(fm, &args);
3162 if (err == -ENOSYS) {
3163 fc->no_copy_file_range = 1;
3164 err = -EOPNOTSUPP;
3165 }
3166 if (err)
3167 goto out;
3168
3169 truncate_inode_pages_range(inode_out->i_mapping,
3170 ALIGN_DOWN(pos_out, PAGE_SIZE),
3171 ALIGN(pos_out + outarg.size, PAGE_SIZE) - 1);
3172
3173 file_update_time(file_out);
3174 fuse_write_update_attr(inode_out, pos_out + outarg.size, outarg.size);
3175
3176 err = outarg.size;
3177out:
3178 if (is_unstable)
3179 clear_bit(FUSE_I_SIZE_UNSTABLE, &fi_out->state);
3180
3181 inode_unlock(inode_out);
3182 file_accessed(file_in);
3183
3184 fuse_flush_time_update(inode_out);
3185
3186 return err;
3187}
3188
3189static ssize_t fuse_copy_file_range(struct file *src_file, loff_t src_off,
3190 struct file *dst_file, loff_t dst_off,
3191 size_t len, unsigned int flags)
3192{
3193 ssize_t ret;
3194
3195 ret = __fuse_copy_file_range(src_file, src_off, dst_file, dst_off,
3196 len, flags);
3197
3198 if (ret == -EOPNOTSUPP || ret == -EXDEV)
3199 ret = generic_copy_file_range(src_file, src_off, dst_file,
3200 dst_off, len, flags);
3201 return ret;
3202}
3203
3204static const struct file_operations fuse_file_operations = {
3205 .llseek = fuse_file_llseek,
3206 .read_iter = fuse_file_read_iter,
3207 .write_iter = fuse_file_write_iter,
3208 .mmap = fuse_file_mmap,
3209 .open = fuse_open,
3210 .flush = fuse_flush,
3211 .release = fuse_release,
3212 .fsync = fuse_fsync,
3213 .lock = fuse_file_lock,
3214 .get_unmapped_area = thp_get_unmapped_area,
3215 .flock = fuse_file_flock,
3216 .splice_read = generic_file_splice_read,
3217 .splice_write = iter_file_splice_write,
3218 .unlocked_ioctl = fuse_file_ioctl,
3219 .compat_ioctl = fuse_file_compat_ioctl,
3220 .poll = fuse_file_poll,
3221 .fallocate = fuse_file_fallocate,
3222 .copy_file_range = fuse_copy_file_range,
3223};
3224
3225static const struct address_space_operations fuse_file_aops = {
3226 .read_folio = fuse_read_folio,
3227 .readahead = fuse_readahead,
3228 .writepage = fuse_writepage,
3229 .writepages = fuse_writepages,
3230 .launder_folio = fuse_launder_folio,
3231 .dirty_folio = filemap_dirty_folio,
3232 .bmap = fuse_bmap,
3233 .direct_IO = fuse_direct_IO,
3234 .write_begin = fuse_write_begin,
3235 .write_end = fuse_write_end,
3236};
3237
3238void fuse_init_file_inode(struct inode *inode, unsigned int flags)
3239{
3240 struct fuse_inode *fi = get_fuse_inode(inode);
3241
3242 inode->i_fop = &fuse_file_operations;
3243 inode->i_data.a_ops = &fuse_file_aops;
3244
3245 INIT_LIST_HEAD(&fi->write_files);
3246 INIT_LIST_HEAD(&fi->queued_writes);
3247 fi->writectr = 0;
3248 init_waitqueue_head(&fi->page_waitq);
3249 fi->writepages = RB_ROOT;
3250
3251 if (IS_ENABLED(CONFIG_FUSE_DAX))
3252 fuse_dax_inode_init(inode, flags);
3253}
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
22static 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
51struct fuse_release_args {
52 struct fuse_args args;
53 struct fuse_release_in inarg;
54 struct inode *inode;
55};
56
57struct 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
84void fuse_file_free(struct fuse_file *ff)
85{
86 kfree(ff->release_args);
87 mutex_destroy(&ff->readdir.lock);
88 kfree(ff);
89}
90
91static struct fuse_file *fuse_file_get(struct fuse_file *ff)
92{
93 refcount_inc(&ff->count);
94 return ff;
95}
96
97static 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
106static 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
127struct 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
169int 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}
179EXPORT_SYMBOL_GPL(fuse_do_open);
180
181static 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
196void 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
225int 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 down_write(&get_fuse_inode(inode)->i_mmap_sem);
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
259out:
260 if (dax_truncate)
261 up_write(&get_fuse_inode(inode)->i_mmap_sem);
262
263 if (is_wb_truncate | dax_truncate) {
264 fuse_release_nowrite(inode);
265 inode_unlock(inode);
266 }
267
268 return err;
269}
270
271static 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
301void 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
329void 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
335static int fuse_open(struct inode *inode, struct file *file)
336{
337 return fuse_open_common(inode, file, false);
338}
339
340static 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
354void 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}
365EXPORT_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 */
371u64 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
389struct 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
398static 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 */
428static 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
441static 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 */
452static 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 */
468static void fuse_sync_writes(struct inode *inode)
469{
470 fuse_set_nowrite(inode);
471 fuse_release_nowrite(inode);
472}
473
474static 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
518inval_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
528int 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
548static 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 }
592out:
593 inode_unlock(inode);
594
595 return err;
596}
597
598void 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
618static 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
630static void fuse_io_release(struct kref *kref)
631{
632 kfree(container_of(kref, struct fuse_io_priv, refcnt));
633}
634
635static 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 */
662static 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
696static 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
714static void fuse_io_free(struct fuse_io_args *ia)
715{
716 kfree(ia->ap.pages);
717 kfree(ia);
718}
719
720static 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
749static 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
770static 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
789static 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
804static 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
820static 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
864static 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
880static 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
921static 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
957static 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
993static 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
1014static 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
1036static 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
1048static 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
1075bool 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
1092static 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
1142static 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
1216static 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
1225static 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
1280static 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
1305writethrough:
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 }
1354out:
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
1363static 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
1368static 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
1374static 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
1430ssize_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}
1516EXPORT_SYMBOL_GPL(fuse_direct_io);
1517
1518static 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
1532static ssize_t fuse_direct_IO(struct kiocb *iocb, struct iov_iter *iter);
1533
1534static 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
1549static 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
1574static 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
1592static 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
1610static 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
1628static 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 */
1646static 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 */
1708void 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
1725static 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
1757static void tree_insert(struct rb_root *root, struct fuse_writepage_args *wpa)
1758{
1759 WARN_ON(fuse_insert_writeback(root, wpa));
1760}
1761
1762static 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
1823static struct fuse_file *__fuse_write_file_get(struct fuse_conn *fc,
1824 struct fuse_inode *fi)
1825{
1826 struct fuse_file *ff = NULL;
1827
1828 spin_lock(&fi->lock);
1829 if (!list_empty(&fi->write_files)) {
1830 ff = list_entry(fi->write_files.next, struct fuse_file,
1831 write_entry);
1832 fuse_file_get(ff);
1833 }
1834 spin_unlock(&fi->lock);
1835
1836 return ff;
1837}
1838
1839static struct fuse_file *fuse_write_file_get(struct fuse_conn *fc,
1840 struct fuse_inode *fi)
1841{
1842 struct fuse_file *ff = __fuse_write_file_get(fc, fi);
1843 WARN_ON(!ff);
1844 return ff;
1845}
1846
1847int fuse_write_inode(struct inode *inode, struct writeback_control *wbc)
1848{
1849 struct fuse_conn *fc = get_fuse_conn(inode);
1850 struct fuse_inode *fi = get_fuse_inode(inode);
1851 struct fuse_file *ff;
1852 int err;
1853
1854 ff = __fuse_write_file_get(fc, fi);
1855 err = fuse_flush_times(inode, ff);
1856 if (ff)
1857 fuse_file_put(ff, false, false);
1858
1859 return err;
1860}
1861
1862static struct fuse_writepage_args *fuse_writepage_args_alloc(void)
1863{
1864 struct fuse_writepage_args *wpa;
1865 struct fuse_args_pages *ap;
1866
1867 wpa = kzalloc(sizeof(*wpa), GFP_NOFS);
1868 if (wpa) {
1869 ap = &wpa->ia.ap;
1870 ap->num_pages = 0;
1871 ap->pages = fuse_pages_alloc(1, GFP_NOFS, &ap->descs);
1872 if (!ap->pages) {
1873 kfree(wpa);
1874 wpa = NULL;
1875 }
1876 }
1877 return wpa;
1878
1879}
1880
1881static void fuse_writepage_add_to_bucket(struct fuse_conn *fc,
1882 struct fuse_writepage_args *wpa)
1883{
1884 if (!fc->sync_fs)
1885 return;
1886
1887 rcu_read_lock();
1888 /* Prevent resurrection of dead bucket in unlikely race with syncfs */
1889 do {
1890 wpa->bucket = rcu_dereference(fc->curr_bucket);
1891 } while (unlikely(!atomic_inc_not_zero(&wpa->bucket->count)));
1892 rcu_read_unlock();
1893}
1894
1895static int fuse_writepage_locked(struct page *page)
1896{
1897 struct address_space *mapping = page->mapping;
1898 struct inode *inode = mapping->host;
1899 struct fuse_conn *fc = get_fuse_conn(inode);
1900 struct fuse_inode *fi = get_fuse_inode(inode);
1901 struct fuse_writepage_args *wpa;
1902 struct fuse_args_pages *ap;
1903 struct page *tmp_page;
1904 int error = -ENOMEM;
1905
1906 set_page_writeback(page);
1907
1908 wpa = fuse_writepage_args_alloc();
1909 if (!wpa)
1910 goto err;
1911 ap = &wpa->ia.ap;
1912
1913 tmp_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
1914 if (!tmp_page)
1915 goto err_free;
1916
1917 error = -EIO;
1918 wpa->ia.ff = fuse_write_file_get(fc, fi);
1919 if (!wpa->ia.ff)
1920 goto err_nofile;
1921
1922 fuse_writepage_add_to_bucket(fc, wpa);
1923 fuse_write_args_fill(&wpa->ia, wpa->ia.ff, page_offset(page), 0);
1924
1925 copy_highpage(tmp_page, page);
1926 wpa->ia.write.in.write_flags |= FUSE_WRITE_CACHE;
1927 wpa->next = NULL;
1928 ap->args.in_pages = true;
1929 ap->num_pages = 1;
1930 ap->pages[0] = tmp_page;
1931 ap->descs[0].offset = 0;
1932 ap->descs[0].length = PAGE_SIZE;
1933 ap->args.end = fuse_writepage_end;
1934 wpa->inode = inode;
1935
1936 inc_wb_stat(&inode_to_bdi(inode)->wb, WB_WRITEBACK);
1937 inc_node_page_state(tmp_page, NR_WRITEBACK_TEMP);
1938
1939 spin_lock(&fi->lock);
1940 tree_insert(&fi->writepages, wpa);
1941 list_add_tail(&wpa->queue_entry, &fi->queued_writes);
1942 fuse_flush_writepages(inode);
1943 spin_unlock(&fi->lock);
1944
1945 end_page_writeback(page);
1946
1947 return 0;
1948
1949err_nofile:
1950 __free_page(tmp_page);
1951err_free:
1952 kfree(wpa);
1953err:
1954 mapping_set_error(page->mapping, error);
1955 end_page_writeback(page);
1956 return error;
1957}
1958
1959static int fuse_writepage(struct page *page, struct writeback_control *wbc)
1960{
1961 int err;
1962
1963 if (fuse_page_is_writeback(page->mapping->host, page->index)) {
1964 /*
1965 * ->writepages() should be called for sync() and friends. We
1966 * should only get here on direct reclaim and then we are
1967 * allowed to skip a page which is already in flight
1968 */
1969 WARN_ON(wbc->sync_mode == WB_SYNC_ALL);
1970
1971 redirty_page_for_writepage(wbc, page);
1972 unlock_page(page);
1973 return 0;
1974 }
1975
1976 err = fuse_writepage_locked(page);
1977 unlock_page(page);
1978
1979 return err;
1980}
1981
1982struct fuse_fill_wb_data {
1983 struct fuse_writepage_args *wpa;
1984 struct fuse_file *ff;
1985 struct inode *inode;
1986 struct page **orig_pages;
1987 unsigned int max_pages;
1988};
1989
1990static bool fuse_pages_realloc(struct fuse_fill_wb_data *data)
1991{
1992 struct fuse_args_pages *ap = &data->wpa->ia.ap;
1993 struct fuse_conn *fc = get_fuse_conn(data->inode);
1994 struct page **pages;
1995 struct fuse_page_desc *descs;
1996 unsigned int npages = min_t(unsigned int,
1997 max_t(unsigned int, data->max_pages * 2,
1998 FUSE_DEFAULT_MAX_PAGES_PER_REQ),
1999 fc->max_pages);
2000 WARN_ON(npages <= data->max_pages);
2001
2002 pages = fuse_pages_alloc(npages, GFP_NOFS, &descs);
2003 if (!pages)
2004 return false;
2005
2006 memcpy(pages, ap->pages, sizeof(struct page *) * ap->num_pages);
2007 memcpy(descs, ap->descs, sizeof(struct fuse_page_desc) * ap->num_pages);
2008 kfree(ap->pages);
2009 ap->pages = pages;
2010 ap->descs = descs;
2011 data->max_pages = npages;
2012
2013 return true;
2014}
2015
2016static void fuse_writepages_send(struct fuse_fill_wb_data *data)
2017{
2018 struct fuse_writepage_args *wpa = data->wpa;
2019 struct inode *inode = data->inode;
2020 struct fuse_inode *fi = get_fuse_inode(inode);
2021 int num_pages = wpa->ia.ap.num_pages;
2022 int i;
2023
2024 wpa->ia.ff = fuse_file_get(data->ff);
2025 spin_lock(&fi->lock);
2026 list_add_tail(&wpa->queue_entry, &fi->queued_writes);
2027 fuse_flush_writepages(inode);
2028 spin_unlock(&fi->lock);
2029
2030 for (i = 0; i < num_pages; i++)
2031 end_page_writeback(data->orig_pages[i]);
2032}
2033
2034/*
2035 * Check under fi->lock if the page is under writeback, and insert it onto the
2036 * rb_tree if not. Otherwise iterate auxiliary write requests, to see if there's
2037 * one already added for a page at this offset. If there's none, then insert
2038 * this new request onto the auxiliary list, otherwise reuse the existing one by
2039 * swapping the new temp page with the old one.
2040 */
2041static bool fuse_writepage_add(struct fuse_writepage_args *new_wpa,
2042 struct page *page)
2043{
2044 struct fuse_inode *fi = get_fuse_inode(new_wpa->inode);
2045 struct fuse_writepage_args *tmp;
2046 struct fuse_writepage_args *old_wpa;
2047 struct fuse_args_pages *new_ap = &new_wpa->ia.ap;
2048
2049 WARN_ON(new_ap->num_pages != 0);
2050 new_ap->num_pages = 1;
2051
2052 spin_lock(&fi->lock);
2053 old_wpa = fuse_insert_writeback(&fi->writepages, new_wpa);
2054 if (!old_wpa) {
2055 spin_unlock(&fi->lock);
2056 return true;
2057 }
2058
2059 for (tmp = old_wpa->next; tmp; tmp = tmp->next) {
2060 pgoff_t curr_index;
2061
2062 WARN_ON(tmp->inode != new_wpa->inode);
2063 curr_index = tmp->ia.write.in.offset >> PAGE_SHIFT;
2064 if (curr_index == page->index) {
2065 WARN_ON(tmp->ia.ap.num_pages != 1);
2066 swap(tmp->ia.ap.pages[0], new_ap->pages[0]);
2067 break;
2068 }
2069 }
2070
2071 if (!tmp) {
2072 new_wpa->next = old_wpa->next;
2073 old_wpa->next = new_wpa;
2074 }
2075
2076 spin_unlock(&fi->lock);
2077
2078 if (tmp) {
2079 struct backing_dev_info *bdi = inode_to_bdi(new_wpa->inode);
2080
2081 dec_wb_stat(&bdi->wb, WB_WRITEBACK);
2082 dec_node_page_state(new_ap->pages[0], NR_WRITEBACK_TEMP);
2083 wb_writeout_inc(&bdi->wb);
2084 fuse_writepage_free(new_wpa);
2085 }
2086
2087 return false;
2088}
2089
2090static bool fuse_writepage_need_send(struct fuse_conn *fc, struct page *page,
2091 struct fuse_args_pages *ap,
2092 struct fuse_fill_wb_data *data)
2093{
2094 WARN_ON(!ap->num_pages);
2095
2096 /*
2097 * Being under writeback is unlikely but possible. For example direct
2098 * read to an mmaped fuse file will set the page dirty twice; once when
2099 * the pages are faulted with get_user_pages(), and then after the read
2100 * completed.
2101 */
2102 if (fuse_page_is_writeback(data->inode, page->index))
2103 return true;
2104
2105 /* Reached max pages */
2106 if (ap->num_pages == fc->max_pages)
2107 return true;
2108
2109 /* Reached max write bytes */
2110 if ((ap->num_pages + 1) * PAGE_SIZE > fc->max_write)
2111 return true;
2112
2113 /* Discontinuity */
2114 if (data->orig_pages[ap->num_pages - 1]->index + 1 != page->index)
2115 return true;
2116
2117 /* Need to grow the pages array? If so, did the expansion fail? */
2118 if (ap->num_pages == data->max_pages && !fuse_pages_realloc(data))
2119 return true;
2120
2121 return false;
2122}
2123
2124static int fuse_writepages_fill(struct page *page,
2125 struct writeback_control *wbc, void *_data)
2126{
2127 struct fuse_fill_wb_data *data = _data;
2128 struct fuse_writepage_args *wpa = data->wpa;
2129 struct fuse_args_pages *ap = &wpa->ia.ap;
2130 struct inode *inode = data->inode;
2131 struct fuse_inode *fi = get_fuse_inode(inode);
2132 struct fuse_conn *fc = get_fuse_conn(inode);
2133 struct page *tmp_page;
2134 int err;
2135
2136 if (!data->ff) {
2137 err = -EIO;
2138 data->ff = fuse_write_file_get(fc, fi);
2139 if (!data->ff)
2140 goto out_unlock;
2141 }
2142
2143 if (wpa && fuse_writepage_need_send(fc, page, ap, data)) {
2144 fuse_writepages_send(data);
2145 data->wpa = NULL;
2146 }
2147
2148 err = -ENOMEM;
2149 tmp_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
2150 if (!tmp_page)
2151 goto out_unlock;
2152
2153 /*
2154 * The page must not be redirtied until the writeout is completed
2155 * (i.e. userspace has sent a reply to the write request). Otherwise
2156 * there could be more than one temporary page instance for each real
2157 * page.
2158 *
2159 * This is ensured by holding the page lock in page_mkwrite() while
2160 * checking fuse_page_is_writeback(). We already hold the page lock
2161 * since clear_page_dirty_for_io() and keep it held until we add the
2162 * request to the fi->writepages list and increment ap->num_pages.
2163 * After this fuse_page_is_writeback() will indicate that the page is
2164 * under writeback, so we can release the page lock.
2165 */
2166 if (data->wpa == NULL) {
2167 err = -ENOMEM;
2168 wpa = fuse_writepage_args_alloc();
2169 if (!wpa) {
2170 __free_page(tmp_page);
2171 goto out_unlock;
2172 }
2173 fuse_writepage_add_to_bucket(fc, wpa);
2174
2175 data->max_pages = 1;
2176
2177 ap = &wpa->ia.ap;
2178 fuse_write_args_fill(&wpa->ia, data->ff, page_offset(page), 0);
2179 wpa->ia.write.in.write_flags |= FUSE_WRITE_CACHE;
2180 wpa->next = NULL;
2181 ap->args.in_pages = true;
2182 ap->args.end = fuse_writepage_end;
2183 ap->num_pages = 0;
2184 wpa->inode = inode;
2185 }
2186 set_page_writeback(page);
2187
2188 copy_highpage(tmp_page, page);
2189 ap->pages[ap->num_pages] = tmp_page;
2190 ap->descs[ap->num_pages].offset = 0;
2191 ap->descs[ap->num_pages].length = PAGE_SIZE;
2192 data->orig_pages[ap->num_pages] = page;
2193
2194 inc_wb_stat(&inode_to_bdi(inode)->wb, WB_WRITEBACK);
2195 inc_node_page_state(tmp_page, NR_WRITEBACK_TEMP);
2196
2197 err = 0;
2198 if (data->wpa) {
2199 /*
2200 * Protected by fi->lock against concurrent access by
2201 * fuse_page_is_writeback().
2202 */
2203 spin_lock(&fi->lock);
2204 ap->num_pages++;
2205 spin_unlock(&fi->lock);
2206 } else if (fuse_writepage_add(wpa, page)) {
2207 data->wpa = wpa;
2208 } else {
2209 end_page_writeback(page);
2210 }
2211out_unlock:
2212 unlock_page(page);
2213
2214 return err;
2215}
2216
2217static int fuse_writepages(struct address_space *mapping,
2218 struct writeback_control *wbc)
2219{
2220 struct inode *inode = mapping->host;
2221 struct fuse_conn *fc = get_fuse_conn(inode);
2222 struct fuse_fill_wb_data data;
2223 int err;
2224
2225 err = -EIO;
2226 if (fuse_is_bad(inode))
2227 goto out;
2228
2229 data.inode = inode;
2230 data.wpa = NULL;
2231 data.ff = NULL;
2232
2233 err = -ENOMEM;
2234 data.orig_pages = kcalloc(fc->max_pages,
2235 sizeof(struct page *),
2236 GFP_NOFS);
2237 if (!data.orig_pages)
2238 goto out;
2239
2240 err = write_cache_pages(mapping, wbc, fuse_writepages_fill, &data);
2241 if (data.wpa) {
2242 WARN_ON(!data.wpa->ia.ap.num_pages);
2243 fuse_writepages_send(&data);
2244 }
2245 if (data.ff)
2246 fuse_file_put(data.ff, false, false);
2247
2248 kfree(data.orig_pages);
2249out:
2250 return err;
2251}
2252
2253/*
2254 * It's worthy to make sure that space is reserved on disk for the write,
2255 * but how to implement it without killing performance need more thinking.
2256 */
2257static int fuse_write_begin(struct file *file, struct address_space *mapping,
2258 loff_t pos, unsigned len, unsigned flags,
2259 struct page **pagep, void **fsdata)
2260{
2261 pgoff_t index = pos >> PAGE_SHIFT;
2262 struct fuse_conn *fc = get_fuse_conn(file_inode(file));
2263 struct page *page;
2264 loff_t fsize;
2265 int err = -ENOMEM;
2266
2267 WARN_ON(!fc->writeback_cache);
2268
2269 page = grab_cache_page_write_begin(mapping, index, flags);
2270 if (!page)
2271 goto error;
2272
2273 fuse_wait_on_page_writeback(mapping->host, page->index);
2274
2275 if (PageUptodate(page) || len == PAGE_SIZE)
2276 goto success;
2277 /*
2278 * Check if the start this page comes after the end of file, in which
2279 * case the readpage can be optimized away.
2280 */
2281 fsize = i_size_read(mapping->host);
2282 if (fsize <= (pos & PAGE_MASK)) {
2283 size_t off = pos & ~PAGE_MASK;
2284 if (off)
2285 zero_user_segment(page, 0, off);
2286 goto success;
2287 }
2288 err = fuse_do_readpage(file, page);
2289 if (err)
2290 goto cleanup;
2291success:
2292 *pagep = page;
2293 return 0;
2294
2295cleanup:
2296 unlock_page(page);
2297 put_page(page);
2298error:
2299 return err;
2300}
2301
2302static int fuse_write_end(struct file *file, struct address_space *mapping,
2303 loff_t pos, unsigned len, unsigned copied,
2304 struct page *page, void *fsdata)
2305{
2306 struct inode *inode = page->mapping->host;
2307
2308 /* Haven't copied anything? Skip zeroing, size extending, dirtying. */
2309 if (!copied)
2310 goto unlock;
2311
2312 if (!PageUptodate(page)) {
2313 /* Zero any unwritten bytes at the end of the page */
2314 size_t endoff = (pos + copied) & ~PAGE_MASK;
2315 if (endoff)
2316 zero_user_segment(page, endoff, PAGE_SIZE);
2317 SetPageUptodate(page);
2318 }
2319
2320 fuse_write_update_size(inode, pos + copied);
2321 set_page_dirty(page);
2322
2323unlock:
2324 unlock_page(page);
2325 put_page(page);
2326
2327 return copied;
2328}
2329
2330static int fuse_launder_page(struct page *page)
2331{
2332 int err = 0;
2333 if (clear_page_dirty_for_io(page)) {
2334 struct inode *inode = page->mapping->host;
2335
2336 /* Serialize with pending writeback for the same page */
2337 fuse_wait_on_page_writeback(inode, page->index);
2338 err = fuse_writepage_locked(page);
2339 if (!err)
2340 fuse_wait_on_page_writeback(inode, page->index);
2341 }
2342 return err;
2343}
2344
2345/*
2346 * Write back dirty pages now, because there may not be any suitable
2347 * open files later
2348 */
2349static void fuse_vma_close(struct vm_area_struct *vma)
2350{
2351 filemap_write_and_wait(vma->vm_file->f_mapping);
2352}
2353
2354/*
2355 * Wait for writeback against this page to complete before allowing it
2356 * to be marked dirty again, and hence written back again, possibly
2357 * before the previous writepage completed.
2358 *
2359 * Block here, instead of in ->writepage(), so that the userspace fs
2360 * can only block processes actually operating on the filesystem.
2361 *
2362 * Otherwise unprivileged userspace fs would be able to block
2363 * unrelated:
2364 *
2365 * - page migration
2366 * - sync(2)
2367 * - try_to_free_pages() with order > PAGE_ALLOC_COSTLY_ORDER
2368 */
2369static vm_fault_t fuse_page_mkwrite(struct vm_fault *vmf)
2370{
2371 struct page *page = vmf->page;
2372 struct inode *inode = file_inode(vmf->vma->vm_file);
2373
2374 file_update_time(vmf->vma->vm_file);
2375 lock_page(page);
2376 if (page->mapping != inode->i_mapping) {
2377 unlock_page(page);
2378 return VM_FAULT_NOPAGE;
2379 }
2380
2381 fuse_wait_on_page_writeback(inode, page->index);
2382 return VM_FAULT_LOCKED;
2383}
2384
2385static const struct vm_operations_struct fuse_file_vm_ops = {
2386 .close = fuse_vma_close,
2387 .fault = filemap_fault,
2388 .map_pages = filemap_map_pages,
2389 .page_mkwrite = fuse_page_mkwrite,
2390};
2391
2392static int fuse_file_mmap(struct file *file, struct vm_area_struct *vma)
2393{
2394 struct fuse_file *ff = file->private_data;
2395
2396 /* DAX mmap is superior to direct_io mmap */
2397 if (FUSE_IS_DAX(file_inode(file)))
2398 return fuse_dax_mmap(file, vma);
2399
2400 if (ff->open_flags & FOPEN_DIRECT_IO) {
2401 /* Can't provide the coherency needed for MAP_SHARED */
2402 if (vma->vm_flags & VM_MAYSHARE)
2403 return -ENODEV;
2404
2405 invalidate_inode_pages2(file->f_mapping);
2406
2407 return generic_file_mmap(file, vma);
2408 }
2409
2410 if ((vma->vm_flags & VM_SHARED) && (vma->vm_flags & VM_MAYWRITE))
2411 fuse_link_write_file(file);
2412
2413 file_accessed(file);
2414 vma->vm_ops = &fuse_file_vm_ops;
2415 return 0;
2416}
2417
2418static int convert_fuse_file_lock(struct fuse_conn *fc,
2419 const struct fuse_file_lock *ffl,
2420 struct file_lock *fl)
2421{
2422 switch (ffl->type) {
2423 case F_UNLCK:
2424 break;
2425
2426 case F_RDLCK:
2427 case F_WRLCK:
2428 if (ffl->start > OFFSET_MAX || ffl->end > OFFSET_MAX ||
2429 ffl->end < ffl->start)
2430 return -EIO;
2431
2432 fl->fl_start = ffl->start;
2433 fl->fl_end = ffl->end;
2434
2435 /*
2436 * Convert pid into init's pid namespace. The locks API will
2437 * translate it into the caller's pid namespace.
2438 */
2439 rcu_read_lock();
2440 fl->fl_pid = pid_nr_ns(find_pid_ns(ffl->pid, fc->pid_ns), &init_pid_ns);
2441 rcu_read_unlock();
2442 break;
2443
2444 default:
2445 return -EIO;
2446 }
2447 fl->fl_type = ffl->type;
2448 return 0;
2449}
2450
2451static void fuse_lk_fill(struct fuse_args *args, struct file *file,
2452 const struct file_lock *fl, int opcode, pid_t pid,
2453 int flock, struct fuse_lk_in *inarg)
2454{
2455 struct inode *inode = file_inode(file);
2456 struct fuse_conn *fc = get_fuse_conn(inode);
2457 struct fuse_file *ff = file->private_data;
2458
2459 memset(inarg, 0, sizeof(*inarg));
2460 inarg->fh = ff->fh;
2461 inarg->owner = fuse_lock_owner_id(fc, fl->fl_owner);
2462 inarg->lk.start = fl->fl_start;
2463 inarg->lk.end = fl->fl_end;
2464 inarg->lk.type = fl->fl_type;
2465 inarg->lk.pid = pid;
2466 if (flock)
2467 inarg->lk_flags |= FUSE_LK_FLOCK;
2468 args->opcode = opcode;
2469 args->nodeid = get_node_id(inode);
2470 args->in_numargs = 1;
2471 args->in_args[0].size = sizeof(*inarg);
2472 args->in_args[0].value = inarg;
2473}
2474
2475static int fuse_getlk(struct file *file, struct file_lock *fl)
2476{
2477 struct inode *inode = file_inode(file);
2478 struct fuse_mount *fm = get_fuse_mount(inode);
2479 FUSE_ARGS(args);
2480 struct fuse_lk_in inarg;
2481 struct fuse_lk_out outarg;
2482 int err;
2483
2484 fuse_lk_fill(&args, file, fl, FUSE_GETLK, 0, 0, &inarg);
2485 args.out_numargs = 1;
2486 args.out_args[0].size = sizeof(outarg);
2487 args.out_args[0].value = &outarg;
2488 err = fuse_simple_request(fm, &args);
2489 if (!err)
2490 err = convert_fuse_file_lock(fm->fc, &outarg.lk, fl);
2491
2492 return err;
2493}
2494
2495static int fuse_setlk(struct file *file, struct file_lock *fl, int flock)
2496{
2497 struct inode *inode = file_inode(file);
2498 struct fuse_mount *fm = get_fuse_mount(inode);
2499 FUSE_ARGS(args);
2500 struct fuse_lk_in inarg;
2501 int opcode = (fl->fl_flags & FL_SLEEP) ? FUSE_SETLKW : FUSE_SETLK;
2502 struct pid *pid = fl->fl_type != F_UNLCK ? task_tgid(current) : NULL;
2503 pid_t pid_nr = pid_nr_ns(pid, fm->fc->pid_ns);
2504 int err;
2505
2506 if (fl->fl_lmops && fl->fl_lmops->lm_grant) {
2507 /* NLM needs asynchronous locks, which we don't support yet */
2508 return -ENOLCK;
2509 }
2510
2511 /* Unlock on close is handled by the flush method */
2512 if ((fl->fl_flags & FL_CLOSE_POSIX) == FL_CLOSE_POSIX)
2513 return 0;
2514
2515 fuse_lk_fill(&args, file, fl, opcode, pid_nr, flock, &inarg);
2516 err = fuse_simple_request(fm, &args);
2517
2518 /* locking is restartable */
2519 if (err == -EINTR)
2520 err = -ERESTARTSYS;
2521
2522 return err;
2523}
2524
2525static int fuse_file_lock(struct file *file, int cmd, struct file_lock *fl)
2526{
2527 struct inode *inode = file_inode(file);
2528 struct fuse_conn *fc = get_fuse_conn(inode);
2529 int err;
2530
2531 if (cmd == F_CANCELLK) {
2532 err = 0;
2533 } else if (cmd == F_GETLK) {
2534 if (fc->no_lock) {
2535 posix_test_lock(file, fl);
2536 err = 0;
2537 } else
2538 err = fuse_getlk(file, fl);
2539 } else {
2540 if (fc->no_lock)
2541 err = posix_lock_file(file, fl, NULL);
2542 else
2543 err = fuse_setlk(file, fl, 0);
2544 }
2545 return err;
2546}
2547
2548static int fuse_file_flock(struct file *file, int cmd, struct file_lock *fl)
2549{
2550 struct inode *inode = file_inode(file);
2551 struct fuse_conn *fc = get_fuse_conn(inode);
2552 int err;
2553
2554 if (fc->no_flock) {
2555 err = locks_lock_file_wait(file, fl);
2556 } else {
2557 struct fuse_file *ff = file->private_data;
2558
2559 /* emulate flock with POSIX locks */
2560 ff->flock = true;
2561 err = fuse_setlk(file, fl, 1);
2562 }
2563
2564 return err;
2565}
2566
2567static sector_t fuse_bmap(struct address_space *mapping, sector_t block)
2568{
2569 struct inode *inode = mapping->host;
2570 struct fuse_mount *fm = get_fuse_mount(inode);
2571 FUSE_ARGS(args);
2572 struct fuse_bmap_in inarg;
2573 struct fuse_bmap_out outarg;
2574 int err;
2575
2576 if (!inode->i_sb->s_bdev || fm->fc->no_bmap)
2577 return 0;
2578
2579 memset(&inarg, 0, sizeof(inarg));
2580 inarg.block = block;
2581 inarg.blocksize = inode->i_sb->s_blocksize;
2582 args.opcode = FUSE_BMAP;
2583 args.nodeid = get_node_id(inode);
2584 args.in_numargs = 1;
2585 args.in_args[0].size = sizeof(inarg);
2586 args.in_args[0].value = &inarg;
2587 args.out_numargs = 1;
2588 args.out_args[0].size = sizeof(outarg);
2589 args.out_args[0].value = &outarg;
2590 err = fuse_simple_request(fm, &args);
2591 if (err == -ENOSYS)
2592 fm->fc->no_bmap = 1;
2593
2594 return err ? 0 : outarg.block;
2595}
2596
2597static loff_t fuse_lseek(struct file *file, loff_t offset, int whence)
2598{
2599 struct inode *inode = file->f_mapping->host;
2600 struct fuse_mount *fm = get_fuse_mount(inode);
2601 struct fuse_file *ff = file->private_data;
2602 FUSE_ARGS(args);
2603 struct fuse_lseek_in inarg = {
2604 .fh = ff->fh,
2605 .offset = offset,
2606 .whence = whence
2607 };
2608 struct fuse_lseek_out outarg;
2609 int err;
2610
2611 if (fm->fc->no_lseek)
2612 goto fallback;
2613
2614 args.opcode = FUSE_LSEEK;
2615 args.nodeid = ff->nodeid;
2616 args.in_numargs = 1;
2617 args.in_args[0].size = sizeof(inarg);
2618 args.in_args[0].value = &inarg;
2619 args.out_numargs = 1;
2620 args.out_args[0].size = sizeof(outarg);
2621 args.out_args[0].value = &outarg;
2622 err = fuse_simple_request(fm, &args);
2623 if (err) {
2624 if (err == -ENOSYS) {
2625 fm->fc->no_lseek = 1;
2626 goto fallback;
2627 }
2628 return err;
2629 }
2630
2631 return vfs_setpos(file, outarg.offset, inode->i_sb->s_maxbytes);
2632
2633fallback:
2634 err = fuse_update_attributes(inode, file);
2635 if (!err)
2636 return generic_file_llseek(file, offset, whence);
2637 else
2638 return err;
2639}
2640
2641static loff_t fuse_file_llseek(struct file *file, loff_t offset, int whence)
2642{
2643 loff_t retval;
2644 struct inode *inode = file_inode(file);
2645
2646 switch (whence) {
2647 case SEEK_SET:
2648 case SEEK_CUR:
2649 /* No i_mutex protection necessary for SEEK_CUR and SEEK_SET */
2650 retval = generic_file_llseek(file, offset, whence);
2651 break;
2652 case SEEK_END:
2653 inode_lock(inode);
2654 retval = fuse_update_attributes(inode, file);
2655 if (!retval)
2656 retval = generic_file_llseek(file, offset, whence);
2657 inode_unlock(inode);
2658 break;
2659 case SEEK_HOLE:
2660 case SEEK_DATA:
2661 inode_lock(inode);
2662 retval = fuse_lseek(file, offset, whence);
2663 inode_unlock(inode);
2664 break;
2665 default:
2666 retval = -EINVAL;
2667 }
2668
2669 return retval;
2670}
2671
2672/*
2673 * All files which have been polled are linked to RB tree
2674 * fuse_conn->polled_files which is indexed by kh. Walk the tree and
2675 * find the matching one.
2676 */
2677static struct rb_node **fuse_find_polled_node(struct fuse_conn *fc, u64 kh,
2678 struct rb_node **parent_out)
2679{
2680 struct rb_node **link = &fc->polled_files.rb_node;
2681 struct rb_node *last = NULL;
2682
2683 while (*link) {
2684 struct fuse_file *ff;
2685
2686 last = *link;
2687 ff = rb_entry(last, struct fuse_file, polled_node);
2688
2689 if (kh < ff->kh)
2690 link = &last->rb_left;
2691 else if (kh > ff->kh)
2692 link = &last->rb_right;
2693 else
2694 return link;
2695 }
2696
2697 if (parent_out)
2698 *parent_out = last;
2699 return link;
2700}
2701
2702/*
2703 * The file is about to be polled. Make sure it's on the polled_files
2704 * RB tree. Note that files once added to the polled_files tree are
2705 * not removed before the file is released. This is because a file
2706 * polled once is likely to be polled again.
2707 */
2708static void fuse_register_polled_file(struct fuse_conn *fc,
2709 struct fuse_file *ff)
2710{
2711 spin_lock(&fc->lock);
2712 if (RB_EMPTY_NODE(&ff->polled_node)) {
2713 struct rb_node **link, *parent;
2714
2715 link = fuse_find_polled_node(fc, ff->kh, &parent);
2716 BUG_ON(*link);
2717 rb_link_node(&ff->polled_node, parent, link);
2718 rb_insert_color(&ff->polled_node, &fc->polled_files);
2719 }
2720 spin_unlock(&fc->lock);
2721}
2722
2723__poll_t fuse_file_poll(struct file *file, poll_table *wait)
2724{
2725 struct fuse_file *ff = file->private_data;
2726 struct fuse_mount *fm = ff->fm;
2727 struct fuse_poll_in inarg = { .fh = ff->fh, .kh = ff->kh };
2728 struct fuse_poll_out outarg;
2729 FUSE_ARGS(args);
2730 int err;
2731
2732 if (fm->fc->no_poll)
2733 return DEFAULT_POLLMASK;
2734
2735 poll_wait(file, &ff->poll_wait, wait);
2736 inarg.events = mangle_poll(poll_requested_events(wait));
2737
2738 /*
2739 * Ask for notification iff there's someone waiting for it.
2740 * The client may ignore the flag and always notify.
2741 */
2742 if (waitqueue_active(&ff->poll_wait)) {
2743 inarg.flags |= FUSE_POLL_SCHEDULE_NOTIFY;
2744 fuse_register_polled_file(fm->fc, ff);
2745 }
2746
2747 args.opcode = FUSE_POLL;
2748 args.nodeid = ff->nodeid;
2749 args.in_numargs = 1;
2750 args.in_args[0].size = sizeof(inarg);
2751 args.in_args[0].value = &inarg;
2752 args.out_numargs = 1;
2753 args.out_args[0].size = sizeof(outarg);
2754 args.out_args[0].value = &outarg;
2755 err = fuse_simple_request(fm, &args);
2756
2757 if (!err)
2758 return demangle_poll(outarg.revents);
2759 if (err == -ENOSYS) {
2760 fm->fc->no_poll = 1;
2761 return DEFAULT_POLLMASK;
2762 }
2763 return EPOLLERR;
2764}
2765EXPORT_SYMBOL_GPL(fuse_file_poll);
2766
2767/*
2768 * This is called from fuse_handle_notify() on FUSE_NOTIFY_POLL and
2769 * wakes up the poll waiters.
2770 */
2771int fuse_notify_poll_wakeup(struct fuse_conn *fc,
2772 struct fuse_notify_poll_wakeup_out *outarg)
2773{
2774 u64 kh = outarg->kh;
2775 struct rb_node **link;
2776
2777 spin_lock(&fc->lock);
2778
2779 link = fuse_find_polled_node(fc, kh, NULL);
2780 if (*link) {
2781 struct fuse_file *ff;
2782
2783 ff = rb_entry(*link, struct fuse_file, polled_node);
2784 wake_up_interruptible_sync(&ff->poll_wait);
2785 }
2786
2787 spin_unlock(&fc->lock);
2788 return 0;
2789}
2790
2791static void fuse_do_truncate(struct file *file)
2792{
2793 struct inode *inode = file->f_mapping->host;
2794 struct iattr attr;
2795
2796 attr.ia_valid = ATTR_SIZE;
2797 attr.ia_size = i_size_read(inode);
2798
2799 attr.ia_file = file;
2800 attr.ia_valid |= ATTR_FILE;
2801
2802 fuse_do_setattr(file_dentry(file), &attr, file);
2803}
2804
2805static inline loff_t fuse_round_up(struct fuse_conn *fc, loff_t off)
2806{
2807 return round_up(off, fc->max_pages << PAGE_SHIFT);
2808}
2809
2810static ssize_t
2811fuse_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
2812{
2813 DECLARE_COMPLETION_ONSTACK(wait);
2814 ssize_t ret = 0;
2815 struct file *file = iocb->ki_filp;
2816 struct fuse_file *ff = file->private_data;
2817 loff_t pos = 0;
2818 struct inode *inode;
2819 loff_t i_size;
2820 size_t count = iov_iter_count(iter), shortened = 0;
2821 loff_t offset = iocb->ki_pos;
2822 struct fuse_io_priv *io;
2823
2824 pos = offset;
2825 inode = file->f_mapping->host;
2826 i_size = i_size_read(inode);
2827
2828 if ((iov_iter_rw(iter) == READ) && (offset >= i_size))
2829 return 0;
2830
2831 io = kmalloc(sizeof(struct fuse_io_priv), GFP_KERNEL);
2832 if (!io)
2833 return -ENOMEM;
2834 spin_lock_init(&io->lock);
2835 kref_init(&io->refcnt);
2836 io->reqs = 1;
2837 io->bytes = -1;
2838 io->size = 0;
2839 io->offset = offset;
2840 io->write = (iov_iter_rw(iter) == WRITE);
2841 io->err = 0;
2842 /*
2843 * By default, we want to optimize all I/Os with async request
2844 * submission to the client filesystem if supported.
2845 */
2846 io->async = ff->fm->fc->async_dio;
2847 io->iocb = iocb;
2848 io->blocking = is_sync_kiocb(iocb);
2849
2850 /* optimization for short read */
2851 if (io->async && !io->write && offset + count > i_size) {
2852 iov_iter_truncate(iter, fuse_round_up(ff->fm->fc, i_size - offset));
2853 shortened = count - iov_iter_count(iter);
2854 count -= shortened;
2855 }
2856
2857 /*
2858 * We cannot asynchronously extend the size of a file.
2859 * In such case the aio will behave exactly like sync io.
2860 */
2861 if ((offset + count > i_size) && io->write)
2862 io->blocking = true;
2863
2864 if (io->async && io->blocking) {
2865 /*
2866 * Additional reference to keep io around after
2867 * calling fuse_aio_complete()
2868 */
2869 kref_get(&io->refcnt);
2870 io->done = &wait;
2871 }
2872
2873 if (iov_iter_rw(iter) == WRITE) {
2874 ret = fuse_direct_io(io, iter, &pos, FUSE_DIO_WRITE);
2875 fuse_invalidate_attr(inode);
2876 } else {
2877 ret = __fuse_direct_read(io, iter, &pos);
2878 }
2879 iov_iter_reexpand(iter, iov_iter_count(iter) + shortened);
2880
2881 if (io->async) {
2882 bool blocking = io->blocking;
2883
2884 fuse_aio_complete(io, ret < 0 ? ret : 0, -1);
2885
2886 /* we have a non-extending, async request, so return */
2887 if (!blocking)
2888 return -EIOCBQUEUED;
2889
2890 wait_for_completion(&wait);
2891 ret = fuse_get_res_by_io(io);
2892 }
2893
2894 kref_put(&io->refcnt, fuse_io_release);
2895
2896 if (iov_iter_rw(iter) == WRITE) {
2897 if (ret > 0)
2898 fuse_write_update_size(inode, pos);
2899 else if (ret < 0 && offset + count > i_size)
2900 fuse_do_truncate(file);
2901 }
2902
2903 return ret;
2904}
2905
2906static int fuse_writeback_range(struct inode *inode, loff_t start, loff_t end)
2907{
2908 int err = filemap_write_and_wait_range(inode->i_mapping, start, -1);
2909
2910 if (!err)
2911 fuse_sync_writes(inode);
2912
2913 return err;
2914}
2915
2916static long fuse_file_fallocate(struct file *file, int mode, loff_t offset,
2917 loff_t length)
2918{
2919 struct fuse_file *ff = file->private_data;
2920 struct inode *inode = file_inode(file);
2921 struct fuse_inode *fi = get_fuse_inode(inode);
2922 struct fuse_mount *fm = ff->fm;
2923 FUSE_ARGS(args);
2924 struct fuse_fallocate_in inarg = {
2925 .fh = ff->fh,
2926 .offset = offset,
2927 .length = length,
2928 .mode = mode
2929 };
2930 int err;
2931 bool lock_inode = !(mode & FALLOC_FL_KEEP_SIZE) ||
2932 (mode & (FALLOC_FL_PUNCH_HOLE |
2933 FALLOC_FL_ZERO_RANGE));
2934
2935 bool block_faults = FUSE_IS_DAX(inode) && lock_inode;
2936
2937 if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE |
2938 FALLOC_FL_ZERO_RANGE))
2939 return -EOPNOTSUPP;
2940
2941 if (fm->fc->no_fallocate)
2942 return -EOPNOTSUPP;
2943
2944 if (lock_inode) {
2945 inode_lock(inode);
2946 if (block_faults) {
2947 down_write(&fi->i_mmap_sem);
2948 err = fuse_dax_break_layouts(inode, 0, 0);
2949 if (err)
2950 goto out;
2951 }
2952
2953 if (mode & (FALLOC_FL_PUNCH_HOLE | FALLOC_FL_ZERO_RANGE)) {
2954 loff_t endbyte = offset + length - 1;
2955
2956 err = fuse_writeback_range(inode, offset, endbyte);
2957 if (err)
2958 goto out;
2959 }
2960 }
2961
2962 if (!(mode & FALLOC_FL_KEEP_SIZE) &&
2963 offset + length > i_size_read(inode)) {
2964 err = inode_newsize_ok(inode, offset + length);
2965 if (err)
2966 goto out;
2967 }
2968
2969 if (!(mode & FALLOC_FL_KEEP_SIZE))
2970 set_bit(FUSE_I_SIZE_UNSTABLE, &fi->state);
2971
2972 args.opcode = FUSE_FALLOCATE;
2973 args.nodeid = ff->nodeid;
2974 args.in_numargs = 1;
2975 args.in_args[0].size = sizeof(inarg);
2976 args.in_args[0].value = &inarg;
2977 err = fuse_simple_request(fm, &args);
2978 if (err == -ENOSYS) {
2979 fm->fc->no_fallocate = 1;
2980 err = -EOPNOTSUPP;
2981 }
2982 if (err)
2983 goto out;
2984
2985 /* we could have extended the file */
2986 if (!(mode & FALLOC_FL_KEEP_SIZE)) {
2987 bool changed = fuse_write_update_size(inode, offset + length);
2988
2989 if (changed && fm->fc->writeback_cache)
2990 file_update_time(file);
2991 }
2992
2993 if (mode & (FALLOC_FL_PUNCH_HOLE | FALLOC_FL_ZERO_RANGE))
2994 truncate_pagecache_range(inode, offset, offset + length - 1);
2995
2996 fuse_invalidate_attr(inode);
2997
2998out:
2999 if (!(mode & FALLOC_FL_KEEP_SIZE))
3000 clear_bit(FUSE_I_SIZE_UNSTABLE, &fi->state);
3001
3002 if (block_faults)
3003 up_write(&fi->i_mmap_sem);
3004
3005 if (lock_inode)
3006 inode_unlock(inode);
3007
3008 return err;
3009}
3010
3011static ssize_t __fuse_copy_file_range(struct file *file_in, loff_t pos_in,
3012 struct file *file_out, loff_t pos_out,
3013 size_t len, unsigned int flags)
3014{
3015 struct fuse_file *ff_in = file_in->private_data;
3016 struct fuse_file *ff_out = file_out->private_data;
3017 struct inode *inode_in = file_inode(file_in);
3018 struct inode *inode_out = file_inode(file_out);
3019 struct fuse_inode *fi_out = get_fuse_inode(inode_out);
3020 struct fuse_mount *fm = ff_in->fm;
3021 struct fuse_conn *fc = fm->fc;
3022 FUSE_ARGS(args);
3023 struct fuse_copy_file_range_in inarg = {
3024 .fh_in = ff_in->fh,
3025 .off_in = pos_in,
3026 .nodeid_out = ff_out->nodeid,
3027 .fh_out = ff_out->fh,
3028 .off_out = pos_out,
3029 .len = len,
3030 .flags = flags
3031 };
3032 struct fuse_write_out outarg;
3033 ssize_t err;
3034 /* mark unstable when write-back is not used, and file_out gets
3035 * extended */
3036 bool is_unstable = (!fc->writeback_cache) &&
3037 ((pos_out + len) > inode_out->i_size);
3038
3039 if (fc->no_copy_file_range)
3040 return -EOPNOTSUPP;
3041
3042 if (file_inode(file_in)->i_sb != file_inode(file_out)->i_sb)
3043 return -EXDEV;
3044
3045 inode_lock(inode_in);
3046 err = fuse_writeback_range(inode_in, pos_in, pos_in + len - 1);
3047 inode_unlock(inode_in);
3048 if (err)
3049 return err;
3050
3051 inode_lock(inode_out);
3052
3053 err = file_modified(file_out);
3054 if (err)
3055 goto out;
3056
3057 /*
3058 * Write out dirty pages in the destination file before sending the COPY
3059 * request to userspace. After the request is completed, truncate off
3060 * pages (including partial ones) from the cache that have been copied,
3061 * since these contain stale data at that point.
3062 *
3063 * This should be mostly correct, but if the COPY writes to partial
3064 * pages (at the start or end) and the parts not covered by the COPY are
3065 * written through a memory map after calling fuse_writeback_range(),
3066 * then these partial page modifications will be lost on truncation.
3067 *
3068 * It is unlikely that someone would rely on such mixed style
3069 * modifications. Yet this does give less guarantees than if the
3070 * copying was performed with write(2).
3071 *
3072 * To fix this a i_mmap_sem style lock could be used to prevent new
3073 * faults while the copy is ongoing.
3074 */
3075 err = fuse_writeback_range(inode_out, pos_out, pos_out + len - 1);
3076 if (err)
3077 goto out;
3078
3079 if (is_unstable)
3080 set_bit(FUSE_I_SIZE_UNSTABLE, &fi_out->state);
3081
3082 args.opcode = FUSE_COPY_FILE_RANGE;
3083 args.nodeid = ff_in->nodeid;
3084 args.in_numargs = 1;
3085 args.in_args[0].size = sizeof(inarg);
3086 args.in_args[0].value = &inarg;
3087 args.out_numargs = 1;
3088 args.out_args[0].size = sizeof(outarg);
3089 args.out_args[0].value = &outarg;
3090 err = fuse_simple_request(fm, &args);
3091 if (err == -ENOSYS) {
3092 fc->no_copy_file_range = 1;
3093 err = -EOPNOTSUPP;
3094 }
3095 if (err)
3096 goto out;
3097
3098 truncate_inode_pages_range(inode_out->i_mapping,
3099 ALIGN_DOWN(pos_out, PAGE_SIZE),
3100 ALIGN(pos_out + outarg.size, PAGE_SIZE) - 1);
3101
3102 if (fc->writeback_cache) {
3103 fuse_write_update_size(inode_out, pos_out + outarg.size);
3104 file_update_time(file_out);
3105 }
3106
3107 fuse_invalidate_attr(inode_out);
3108
3109 err = outarg.size;
3110out:
3111 if (is_unstable)
3112 clear_bit(FUSE_I_SIZE_UNSTABLE, &fi_out->state);
3113
3114 inode_unlock(inode_out);
3115 file_accessed(file_in);
3116
3117 return err;
3118}
3119
3120static ssize_t fuse_copy_file_range(struct file *src_file, loff_t src_off,
3121 struct file *dst_file, loff_t dst_off,
3122 size_t len, unsigned int flags)
3123{
3124 ssize_t ret;
3125
3126 ret = __fuse_copy_file_range(src_file, src_off, dst_file, dst_off,
3127 len, flags);
3128
3129 if (ret == -EOPNOTSUPP || ret == -EXDEV)
3130 ret = generic_copy_file_range(src_file, src_off, dst_file,
3131 dst_off, len, flags);
3132 return ret;
3133}
3134
3135static const struct file_operations fuse_file_operations = {
3136 .llseek = fuse_file_llseek,
3137 .read_iter = fuse_file_read_iter,
3138 .write_iter = fuse_file_write_iter,
3139 .mmap = fuse_file_mmap,
3140 .open = fuse_open,
3141 .flush = fuse_flush,
3142 .release = fuse_release,
3143 .fsync = fuse_fsync,
3144 .lock = fuse_file_lock,
3145 .get_unmapped_area = thp_get_unmapped_area,
3146 .flock = fuse_file_flock,
3147 .splice_read = generic_file_splice_read,
3148 .splice_write = iter_file_splice_write,
3149 .unlocked_ioctl = fuse_file_ioctl,
3150 .compat_ioctl = fuse_file_compat_ioctl,
3151 .poll = fuse_file_poll,
3152 .fallocate = fuse_file_fallocate,
3153 .copy_file_range = fuse_copy_file_range,
3154};
3155
3156static const struct address_space_operations fuse_file_aops = {
3157 .readpage = fuse_readpage,
3158 .readahead = fuse_readahead,
3159 .writepage = fuse_writepage,
3160 .writepages = fuse_writepages,
3161 .launder_page = fuse_launder_page,
3162 .set_page_dirty = __set_page_dirty_nobuffers,
3163 .bmap = fuse_bmap,
3164 .direct_IO = fuse_direct_IO,
3165 .write_begin = fuse_write_begin,
3166 .write_end = fuse_write_end,
3167};
3168
3169void fuse_init_file_inode(struct inode *inode)
3170{
3171 struct fuse_inode *fi = get_fuse_inode(inode);
3172
3173 inode->i_fop = &fuse_file_operations;
3174 inode->i_data.a_ops = &fuse_file_aops;
3175
3176 INIT_LIST_HEAD(&fi->write_files);
3177 INIT_LIST_HEAD(&fi->queued_writes);
3178 fi->writectr = 0;
3179 init_waitqueue_head(&fi->page_waitq);
3180 fi->writepages = RB_ROOT;
3181
3182 if (IS_ENABLED(CONFIG_FUSE_DAX))
3183 fuse_dax_inode_init(inode);
3184}