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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#include <linux/filelock.h>
22#include <linux/splice.h>
23#include <linux/task_io_accounting_ops.h>
24
25static int fuse_send_open(struct fuse_mount *fm, u64 nodeid,
26 unsigned int open_flags, int opcode,
27 struct fuse_open_out *outargp)
28{
29 struct fuse_open_in inarg;
30 FUSE_ARGS(args);
31
32 memset(&inarg, 0, sizeof(inarg));
33 inarg.flags = open_flags & ~(O_CREAT | O_EXCL | O_NOCTTY);
34 if (!fm->fc->atomic_o_trunc)
35 inarg.flags &= ~O_TRUNC;
36
37 if (fm->fc->handle_killpriv_v2 &&
38 (inarg.flags & O_TRUNC) && !capable(CAP_FSETID)) {
39 inarg.open_flags |= FUSE_OPEN_KILL_SUIDGID;
40 }
41
42 args.opcode = opcode;
43 args.nodeid = nodeid;
44 args.in_numargs = 1;
45 args.in_args[0].size = sizeof(inarg);
46 args.in_args[0].value = &inarg;
47 args.out_numargs = 1;
48 args.out_args[0].size = sizeof(*outargp);
49 args.out_args[0].value = outargp;
50
51 return fuse_simple_request(fm, &args);
52}
53
54struct fuse_file *fuse_file_alloc(struct fuse_mount *fm, bool release)
55{
56 struct fuse_file *ff;
57
58 ff = kzalloc(sizeof(struct fuse_file), GFP_KERNEL_ACCOUNT);
59 if (unlikely(!ff))
60 return NULL;
61
62 ff->fm = fm;
63 if (release) {
64 ff->args = kzalloc(sizeof(*ff->args), GFP_KERNEL_ACCOUNT);
65 if (!ff->args) {
66 kfree(ff);
67 return NULL;
68 }
69 }
70
71 INIT_LIST_HEAD(&ff->write_entry);
72 refcount_set(&ff->count, 1);
73 RB_CLEAR_NODE(&ff->polled_node);
74 init_waitqueue_head(&ff->poll_wait);
75
76 ff->kh = atomic64_inc_return(&fm->fc->khctr);
77
78 return ff;
79}
80
81void fuse_file_free(struct fuse_file *ff)
82{
83 kfree(ff->args);
84 kfree(ff);
85}
86
87static struct fuse_file *fuse_file_get(struct fuse_file *ff)
88{
89 refcount_inc(&ff->count);
90 return ff;
91}
92
93static void fuse_release_end(struct fuse_mount *fm, struct fuse_args *args,
94 int error)
95{
96 struct fuse_release_args *ra = container_of(args, typeof(*ra), args);
97
98 iput(ra->inode);
99 kfree(ra);
100}
101
102static void fuse_file_put(struct fuse_file *ff, bool sync)
103{
104 if (refcount_dec_and_test(&ff->count)) {
105 struct fuse_release_args *ra = &ff->args->release_args;
106 struct fuse_args *args = (ra ? &ra->args : NULL);
107
108 if (ra && ra->inode)
109 fuse_file_io_release(ff, ra->inode);
110
111 if (!args) {
112 /* Do nothing when server does not implement 'open' */
113 } else if (sync) {
114 fuse_simple_request(ff->fm, args);
115 fuse_release_end(ff->fm, args, 0);
116 } else {
117 args->end = fuse_release_end;
118 if (fuse_simple_background(ff->fm, args,
119 GFP_KERNEL | __GFP_NOFAIL))
120 fuse_release_end(ff->fm, args, -ENOTCONN);
121 }
122 kfree(ff);
123 }
124}
125
126struct fuse_file *fuse_file_open(struct fuse_mount *fm, u64 nodeid,
127 unsigned int open_flags, bool isdir)
128{
129 struct fuse_conn *fc = fm->fc;
130 struct fuse_file *ff;
131 int opcode = isdir ? FUSE_OPENDIR : FUSE_OPEN;
132 bool open = isdir ? !fc->no_opendir : !fc->no_open;
133
134 ff = fuse_file_alloc(fm, open);
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 (open) {
142 /* Store outarg for fuse_finish_open() */
143 struct fuse_open_out *outargp = &ff->args->open_outarg;
144 int err;
145
146 err = fuse_send_open(fm, nodeid, open_flags, opcode, outargp);
147 if (!err) {
148 ff->fh = outargp->fh;
149 ff->open_flags = outargp->open_flags;
150 } else if (err != -ENOSYS) {
151 fuse_file_free(ff);
152 return ERR_PTR(err);
153 } else {
154 /* No release needed */
155 kfree(ff->args);
156 ff->args = NULL;
157 if (isdir)
158 fc->no_opendir = 1;
159 else
160 fc->no_open = 1;
161 }
162 }
163
164 if (isdir)
165 ff->open_flags &= ~FOPEN_DIRECT_IO;
166
167 ff->nodeid = nodeid;
168
169 return ff;
170}
171
172int fuse_do_open(struct fuse_mount *fm, u64 nodeid, struct file *file,
173 bool isdir)
174{
175 struct fuse_file *ff = fuse_file_open(fm, nodeid, file->f_flags, isdir);
176
177 if (!IS_ERR(ff))
178 file->private_data = ff;
179
180 return PTR_ERR_OR_ZERO(ff);
181}
182EXPORT_SYMBOL_GPL(fuse_do_open);
183
184static void fuse_link_write_file(struct file *file)
185{
186 struct inode *inode = file_inode(file);
187 struct fuse_inode *fi = get_fuse_inode(inode);
188 struct fuse_file *ff = file->private_data;
189 /*
190 * file may be written through mmap, so chain it onto the
191 * inodes's write_file list
192 */
193 spin_lock(&fi->lock);
194 if (list_empty(&ff->write_entry))
195 list_add(&ff->write_entry, &fi->write_files);
196 spin_unlock(&fi->lock);
197}
198
199int fuse_finish_open(struct inode *inode, struct file *file)
200{
201 struct fuse_file *ff = file->private_data;
202 struct fuse_conn *fc = get_fuse_conn(inode);
203 int err;
204
205 err = fuse_file_io_open(file, inode);
206 if (err)
207 return err;
208
209 if (ff->open_flags & FOPEN_STREAM)
210 stream_open(inode, file);
211 else if (ff->open_flags & FOPEN_NONSEEKABLE)
212 nonseekable_open(inode, file);
213
214 if ((file->f_mode & FMODE_WRITE) && fc->writeback_cache)
215 fuse_link_write_file(file);
216
217 return 0;
218}
219
220static void fuse_truncate_update_attr(struct inode *inode, struct file *file)
221{
222 struct fuse_conn *fc = get_fuse_conn(inode);
223 struct fuse_inode *fi = get_fuse_inode(inode);
224
225 spin_lock(&fi->lock);
226 fi->attr_version = atomic64_inc_return(&fc->attr_version);
227 i_size_write(inode, 0);
228 spin_unlock(&fi->lock);
229 file_update_time(file);
230 fuse_invalidate_attr_mask(inode, FUSE_STATX_MODSIZE);
231}
232
233static int fuse_open(struct inode *inode, struct file *file)
234{
235 struct fuse_mount *fm = get_fuse_mount(inode);
236 struct fuse_inode *fi = get_fuse_inode(inode);
237 struct fuse_conn *fc = fm->fc;
238 struct fuse_file *ff;
239 int err;
240 bool is_truncate = (file->f_flags & O_TRUNC) && fc->atomic_o_trunc;
241 bool is_wb_truncate = is_truncate && fc->writeback_cache;
242 bool dax_truncate = is_truncate && FUSE_IS_DAX(inode);
243
244 if (fuse_is_bad(inode))
245 return -EIO;
246
247 err = generic_file_open(inode, file);
248 if (err)
249 return err;
250
251 if (is_wb_truncate || dax_truncate)
252 inode_lock(inode);
253
254 if (dax_truncate) {
255 filemap_invalidate_lock(inode->i_mapping);
256 err = fuse_dax_break_layouts(inode, 0, 0);
257 if (err)
258 goto out_inode_unlock;
259 }
260
261 if (is_wb_truncate || dax_truncate)
262 fuse_set_nowrite(inode);
263
264 err = fuse_do_open(fm, get_node_id(inode), file, false);
265 if (!err) {
266 ff = file->private_data;
267 err = fuse_finish_open(inode, file);
268 if (err)
269 fuse_sync_release(fi, ff, file->f_flags);
270 else if (is_truncate)
271 fuse_truncate_update_attr(inode, file);
272 }
273
274 if (is_wb_truncate || dax_truncate)
275 fuse_release_nowrite(inode);
276 if (!err) {
277 if (is_truncate)
278 truncate_pagecache(inode, 0);
279 else if (!(ff->open_flags & FOPEN_KEEP_CACHE))
280 invalidate_inode_pages2(inode->i_mapping);
281 }
282 if (dax_truncate)
283 filemap_invalidate_unlock(inode->i_mapping);
284out_inode_unlock:
285 if (is_wb_truncate || dax_truncate)
286 inode_unlock(inode);
287
288 return err;
289}
290
291static void fuse_prepare_release(struct fuse_inode *fi, struct fuse_file *ff,
292 unsigned int flags, int opcode, bool sync)
293{
294 struct fuse_conn *fc = ff->fm->fc;
295 struct fuse_release_args *ra = &ff->args->release_args;
296
297 if (fuse_file_passthrough(ff))
298 fuse_passthrough_release(ff, fuse_inode_backing(fi));
299
300 /* Inode is NULL on error path of fuse_create_open() */
301 if (likely(fi)) {
302 spin_lock(&fi->lock);
303 list_del(&ff->write_entry);
304 spin_unlock(&fi->lock);
305 }
306 spin_lock(&fc->lock);
307 if (!RB_EMPTY_NODE(&ff->polled_node))
308 rb_erase(&ff->polled_node, &fc->polled_files);
309 spin_unlock(&fc->lock);
310
311 wake_up_interruptible_all(&ff->poll_wait);
312
313 if (!ra)
314 return;
315
316 /* ff->args was used for open outarg */
317 memset(ff->args, 0, sizeof(*ff->args));
318 ra->inarg.fh = ff->fh;
319 ra->inarg.flags = flags;
320 ra->args.in_numargs = 1;
321 ra->args.in_args[0].size = sizeof(struct fuse_release_in);
322 ra->args.in_args[0].value = &ra->inarg;
323 ra->args.opcode = opcode;
324 ra->args.nodeid = ff->nodeid;
325 ra->args.force = true;
326 ra->args.nocreds = true;
327
328 /*
329 * Hold inode until release is finished.
330 * From fuse_sync_release() the refcount is 1 and everything's
331 * synchronous, so we are fine with not doing igrab() here.
332 */
333 ra->inode = sync ? NULL : igrab(&fi->inode);
334}
335
336void fuse_file_release(struct inode *inode, struct fuse_file *ff,
337 unsigned int open_flags, fl_owner_t id, bool isdir)
338{
339 struct fuse_inode *fi = get_fuse_inode(inode);
340 struct fuse_release_args *ra = &ff->args->release_args;
341 int opcode = isdir ? FUSE_RELEASEDIR : FUSE_RELEASE;
342
343 fuse_prepare_release(fi, ff, open_flags, opcode, false);
344
345 if (ra && ff->flock) {
346 ra->inarg.release_flags |= FUSE_RELEASE_FLOCK_UNLOCK;
347 ra->inarg.lock_owner = fuse_lock_owner_id(ff->fm->fc, id);
348 }
349
350 /*
351 * Normally this will send the RELEASE request, however if
352 * some asynchronous READ or WRITE requests are outstanding,
353 * the sending will be delayed.
354 *
355 * Make the release synchronous if this is a fuseblk mount,
356 * synchronous RELEASE is allowed (and desirable) in this case
357 * because the server can be trusted not to screw up.
358 */
359 fuse_file_put(ff, ff->fm->fc->destroy);
360}
361
362void fuse_release_common(struct file *file, bool isdir)
363{
364 fuse_file_release(file_inode(file), file->private_data, file->f_flags,
365 (fl_owner_t) file, isdir);
366}
367
368static int fuse_release(struct inode *inode, struct file *file)
369{
370 struct fuse_conn *fc = get_fuse_conn(inode);
371
372 /*
373 * Dirty pages might remain despite write_inode_now() call from
374 * fuse_flush() due to writes racing with the close.
375 */
376 if (fc->writeback_cache)
377 write_inode_now(inode, 1);
378
379 fuse_release_common(file, false);
380
381 /* return value is ignored by VFS */
382 return 0;
383}
384
385void fuse_sync_release(struct fuse_inode *fi, struct fuse_file *ff,
386 unsigned int flags)
387{
388 WARN_ON(refcount_read(&ff->count) > 1);
389 fuse_prepare_release(fi, ff, flags, FUSE_RELEASE, true);
390 fuse_file_put(ff, true);
391}
392EXPORT_SYMBOL_GPL(fuse_sync_release);
393
394/*
395 * Scramble the ID space with XTEA, so that the value of the files_struct
396 * pointer is not exposed to userspace.
397 */
398u64 fuse_lock_owner_id(struct fuse_conn *fc, fl_owner_t id)
399{
400 u32 *k = fc->scramble_key;
401 u64 v = (unsigned long) id;
402 u32 v0 = v;
403 u32 v1 = v >> 32;
404 u32 sum = 0;
405 int i;
406
407 for (i = 0; i < 32; i++) {
408 v0 += ((v1 << 4 ^ v1 >> 5) + v1) ^ (sum + k[sum & 3]);
409 sum += 0x9E3779B9;
410 v1 += ((v0 << 4 ^ v0 >> 5) + v0) ^ (sum + k[sum>>11 & 3]);
411 }
412
413 return (u64) v0 + ((u64) v1 << 32);
414}
415
416struct fuse_writepage_args {
417 struct fuse_io_args ia;
418 struct rb_node writepages_entry;
419 struct list_head queue_entry;
420 struct fuse_writepage_args *next;
421 struct inode *inode;
422 struct fuse_sync_bucket *bucket;
423};
424
425static struct fuse_writepage_args *fuse_find_writeback(struct fuse_inode *fi,
426 pgoff_t idx_from, pgoff_t idx_to)
427{
428 struct rb_node *n;
429
430 n = fi->writepages.rb_node;
431
432 while (n) {
433 struct fuse_writepage_args *wpa;
434 pgoff_t curr_index;
435
436 wpa = rb_entry(n, struct fuse_writepage_args, writepages_entry);
437 WARN_ON(get_fuse_inode(wpa->inode) != fi);
438 curr_index = wpa->ia.write.in.offset >> PAGE_SHIFT;
439 if (idx_from >= curr_index + wpa->ia.ap.num_pages)
440 n = n->rb_right;
441 else if (idx_to < curr_index)
442 n = n->rb_left;
443 else
444 return wpa;
445 }
446 return NULL;
447}
448
449/*
450 * Check if any page in a range is under writeback
451 *
452 * This is currently done by walking the list of writepage requests
453 * for the inode, which can be pretty inefficient.
454 */
455static bool fuse_range_is_writeback(struct inode *inode, pgoff_t idx_from,
456 pgoff_t idx_to)
457{
458 struct fuse_inode *fi = get_fuse_inode(inode);
459 bool found;
460
461 spin_lock(&fi->lock);
462 found = fuse_find_writeback(fi, idx_from, idx_to);
463 spin_unlock(&fi->lock);
464
465 return found;
466}
467
468static inline bool fuse_page_is_writeback(struct inode *inode, pgoff_t index)
469{
470 return fuse_range_is_writeback(inode, index, index);
471}
472
473/*
474 * Wait for page writeback to be completed.
475 *
476 * Since fuse doesn't rely on the VM writeback tracking, this has to
477 * use some other means.
478 */
479static void fuse_wait_on_page_writeback(struct inode *inode, pgoff_t index)
480{
481 struct fuse_inode *fi = get_fuse_inode(inode);
482
483 wait_event(fi->page_waitq, !fuse_page_is_writeback(inode, index));
484}
485
486/*
487 * Wait for all pending writepages on the inode to finish.
488 *
489 * This is currently done by blocking further writes with FUSE_NOWRITE
490 * and waiting for all sent writes to complete.
491 *
492 * This must be called under i_mutex, otherwise the FUSE_NOWRITE usage
493 * could conflict with truncation.
494 */
495static void fuse_sync_writes(struct inode *inode)
496{
497 fuse_set_nowrite(inode);
498 fuse_release_nowrite(inode);
499}
500
501static int fuse_flush(struct file *file, fl_owner_t id)
502{
503 struct inode *inode = file_inode(file);
504 struct fuse_mount *fm = get_fuse_mount(inode);
505 struct fuse_file *ff = file->private_data;
506 struct fuse_flush_in inarg;
507 FUSE_ARGS(args);
508 int err;
509
510 if (fuse_is_bad(inode))
511 return -EIO;
512
513 if (ff->open_flags & FOPEN_NOFLUSH && !fm->fc->writeback_cache)
514 return 0;
515
516 err = write_inode_now(inode, 1);
517 if (err)
518 return err;
519
520 inode_lock(inode);
521 fuse_sync_writes(inode);
522 inode_unlock(inode);
523
524 err = filemap_check_errors(file->f_mapping);
525 if (err)
526 return err;
527
528 err = 0;
529 if (fm->fc->no_flush)
530 goto inval_attr_out;
531
532 memset(&inarg, 0, sizeof(inarg));
533 inarg.fh = ff->fh;
534 inarg.lock_owner = fuse_lock_owner_id(fm->fc, id);
535 args.opcode = FUSE_FLUSH;
536 args.nodeid = get_node_id(inode);
537 args.in_numargs = 1;
538 args.in_args[0].size = sizeof(inarg);
539 args.in_args[0].value = &inarg;
540 args.force = true;
541
542 err = fuse_simple_request(fm, &args);
543 if (err == -ENOSYS) {
544 fm->fc->no_flush = 1;
545 err = 0;
546 }
547
548inval_attr_out:
549 /*
550 * In memory i_blocks is not maintained by fuse, if writeback cache is
551 * enabled, i_blocks from cached attr may not be accurate.
552 */
553 if (!err && fm->fc->writeback_cache)
554 fuse_invalidate_attr_mask(inode, STATX_BLOCKS);
555 return err;
556}
557
558int fuse_fsync_common(struct file *file, loff_t start, loff_t end,
559 int datasync, int opcode)
560{
561 struct inode *inode = file->f_mapping->host;
562 struct fuse_mount *fm = get_fuse_mount(inode);
563 struct fuse_file *ff = file->private_data;
564 FUSE_ARGS(args);
565 struct fuse_fsync_in inarg;
566
567 memset(&inarg, 0, sizeof(inarg));
568 inarg.fh = ff->fh;
569 inarg.fsync_flags = datasync ? FUSE_FSYNC_FDATASYNC : 0;
570 args.opcode = opcode;
571 args.nodeid = get_node_id(inode);
572 args.in_numargs = 1;
573 args.in_args[0].size = sizeof(inarg);
574 args.in_args[0].value = &inarg;
575 return fuse_simple_request(fm, &args);
576}
577
578static int fuse_fsync(struct file *file, loff_t start, loff_t end,
579 int datasync)
580{
581 struct inode *inode = file->f_mapping->host;
582 struct fuse_conn *fc = get_fuse_conn(inode);
583 int err;
584
585 if (fuse_is_bad(inode))
586 return -EIO;
587
588 inode_lock(inode);
589
590 /*
591 * Start writeback against all dirty pages of the inode, then
592 * wait for all outstanding writes, before sending the FSYNC
593 * request.
594 */
595 err = file_write_and_wait_range(file, start, end);
596 if (err)
597 goto out;
598
599 fuse_sync_writes(inode);
600
601 /*
602 * Due to implementation of fuse writeback
603 * file_write_and_wait_range() does not catch errors.
604 * We have to do this directly after fuse_sync_writes()
605 */
606 err = file_check_and_advance_wb_err(file);
607 if (err)
608 goto out;
609
610 err = sync_inode_metadata(inode, 1);
611 if (err)
612 goto out;
613
614 if (fc->no_fsync)
615 goto out;
616
617 err = fuse_fsync_common(file, start, end, datasync, FUSE_FSYNC);
618 if (err == -ENOSYS) {
619 fc->no_fsync = 1;
620 err = 0;
621 }
622out:
623 inode_unlock(inode);
624
625 return err;
626}
627
628void fuse_read_args_fill(struct fuse_io_args *ia, struct file *file, loff_t pos,
629 size_t count, int opcode)
630{
631 struct fuse_file *ff = file->private_data;
632 struct fuse_args *args = &ia->ap.args;
633
634 ia->read.in.fh = ff->fh;
635 ia->read.in.offset = pos;
636 ia->read.in.size = count;
637 ia->read.in.flags = file->f_flags;
638 args->opcode = opcode;
639 args->nodeid = ff->nodeid;
640 args->in_numargs = 1;
641 args->in_args[0].size = sizeof(ia->read.in);
642 args->in_args[0].value = &ia->read.in;
643 args->out_argvar = true;
644 args->out_numargs = 1;
645 args->out_args[0].size = count;
646}
647
648static void fuse_release_user_pages(struct fuse_args_pages *ap,
649 bool should_dirty)
650{
651 unsigned int i;
652
653 for (i = 0; i < ap->num_pages; i++) {
654 if (should_dirty)
655 set_page_dirty_lock(ap->pages[i]);
656 if (ap->args.is_pinned)
657 unpin_user_page(ap->pages[i]);
658 }
659}
660
661static void fuse_io_release(struct kref *kref)
662{
663 kfree(container_of(kref, struct fuse_io_priv, refcnt));
664}
665
666static ssize_t fuse_get_res_by_io(struct fuse_io_priv *io)
667{
668 if (io->err)
669 return io->err;
670
671 if (io->bytes >= 0 && io->write)
672 return -EIO;
673
674 return io->bytes < 0 ? io->size : io->bytes;
675}
676
677/*
678 * In case of short read, the caller sets 'pos' to the position of
679 * actual end of fuse request in IO request. Otherwise, if bytes_requested
680 * == bytes_transferred or rw == WRITE, the caller sets 'pos' to -1.
681 *
682 * An example:
683 * User requested DIO read of 64K. It was split into two 32K fuse requests,
684 * both submitted asynchronously. The first of them was ACKed by userspace as
685 * fully completed (req->out.args[0].size == 32K) resulting in pos == -1. The
686 * second request was ACKed as short, e.g. only 1K was read, resulting in
687 * pos == 33K.
688 *
689 * Thus, when all fuse requests are completed, the minimal non-negative 'pos'
690 * will be equal to the length of the longest contiguous fragment of
691 * transferred data starting from the beginning of IO request.
692 */
693static void fuse_aio_complete(struct fuse_io_priv *io, int err, ssize_t pos)
694{
695 int left;
696
697 spin_lock(&io->lock);
698 if (err)
699 io->err = io->err ? : err;
700 else if (pos >= 0 && (io->bytes < 0 || pos < io->bytes))
701 io->bytes = pos;
702
703 left = --io->reqs;
704 if (!left && io->blocking)
705 complete(io->done);
706 spin_unlock(&io->lock);
707
708 if (!left && !io->blocking) {
709 ssize_t res = fuse_get_res_by_io(io);
710
711 if (res >= 0) {
712 struct inode *inode = file_inode(io->iocb->ki_filp);
713 struct fuse_conn *fc = get_fuse_conn(inode);
714 struct fuse_inode *fi = get_fuse_inode(inode);
715
716 spin_lock(&fi->lock);
717 fi->attr_version = atomic64_inc_return(&fc->attr_version);
718 spin_unlock(&fi->lock);
719 }
720
721 io->iocb->ki_complete(io->iocb, res);
722 }
723
724 kref_put(&io->refcnt, fuse_io_release);
725}
726
727static struct fuse_io_args *fuse_io_alloc(struct fuse_io_priv *io,
728 unsigned int npages)
729{
730 struct fuse_io_args *ia;
731
732 ia = kzalloc(sizeof(*ia), GFP_KERNEL);
733 if (ia) {
734 ia->io = io;
735 ia->ap.pages = fuse_pages_alloc(npages, GFP_KERNEL,
736 &ia->ap.descs);
737 if (!ia->ap.pages) {
738 kfree(ia);
739 ia = NULL;
740 }
741 }
742 return ia;
743}
744
745static void fuse_io_free(struct fuse_io_args *ia)
746{
747 kfree(ia->ap.pages);
748 kfree(ia);
749}
750
751static void fuse_aio_complete_req(struct fuse_mount *fm, struct fuse_args *args,
752 int err)
753{
754 struct fuse_io_args *ia = container_of(args, typeof(*ia), ap.args);
755 struct fuse_io_priv *io = ia->io;
756 ssize_t pos = -1;
757
758 fuse_release_user_pages(&ia->ap, io->should_dirty);
759
760 if (err) {
761 /* Nothing */
762 } else if (io->write) {
763 if (ia->write.out.size > ia->write.in.size) {
764 err = -EIO;
765 } else if (ia->write.in.size != ia->write.out.size) {
766 pos = ia->write.in.offset - io->offset +
767 ia->write.out.size;
768 }
769 } else {
770 u32 outsize = args->out_args[0].size;
771
772 if (ia->read.in.size != outsize)
773 pos = ia->read.in.offset - io->offset + outsize;
774 }
775
776 fuse_aio_complete(io, err, pos);
777 fuse_io_free(ia);
778}
779
780static ssize_t fuse_async_req_send(struct fuse_mount *fm,
781 struct fuse_io_args *ia, size_t num_bytes)
782{
783 ssize_t err;
784 struct fuse_io_priv *io = ia->io;
785
786 spin_lock(&io->lock);
787 kref_get(&io->refcnt);
788 io->size += num_bytes;
789 io->reqs++;
790 spin_unlock(&io->lock);
791
792 ia->ap.args.end = fuse_aio_complete_req;
793 ia->ap.args.may_block = io->should_dirty;
794 err = fuse_simple_background(fm, &ia->ap.args, GFP_KERNEL);
795 if (err)
796 fuse_aio_complete_req(fm, &ia->ap.args, err);
797
798 return num_bytes;
799}
800
801static ssize_t fuse_send_read(struct fuse_io_args *ia, loff_t pos, size_t count,
802 fl_owner_t owner)
803{
804 struct file *file = ia->io->iocb->ki_filp;
805 struct fuse_file *ff = file->private_data;
806 struct fuse_mount *fm = ff->fm;
807
808 fuse_read_args_fill(ia, file, pos, count, FUSE_READ);
809 if (owner != NULL) {
810 ia->read.in.read_flags |= FUSE_READ_LOCKOWNER;
811 ia->read.in.lock_owner = fuse_lock_owner_id(fm->fc, owner);
812 }
813
814 if (ia->io->async)
815 return fuse_async_req_send(fm, ia, count);
816
817 return fuse_simple_request(fm, &ia->ap.args);
818}
819
820static void fuse_read_update_size(struct inode *inode, loff_t size,
821 u64 attr_ver)
822{
823 struct fuse_conn *fc = get_fuse_conn(inode);
824 struct fuse_inode *fi = get_fuse_inode(inode);
825
826 spin_lock(&fi->lock);
827 if (attr_ver >= fi->attr_version && size < inode->i_size &&
828 !test_bit(FUSE_I_SIZE_UNSTABLE, &fi->state)) {
829 fi->attr_version = atomic64_inc_return(&fc->attr_version);
830 i_size_write(inode, size);
831 }
832 spin_unlock(&fi->lock);
833}
834
835static void fuse_short_read(struct inode *inode, u64 attr_ver, size_t num_read,
836 struct fuse_args_pages *ap)
837{
838 struct fuse_conn *fc = get_fuse_conn(inode);
839
840 /*
841 * If writeback_cache is enabled, a short read means there's a hole in
842 * the file. Some data after the hole is in page cache, but has not
843 * reached the client fs yet. So the hole is not present there.
844 */
845 if (!fc->writeback_cache) {
846 loff_t pos = page_offset(ap->pages[0]) + num_read;
847 fuse_read_update_size(inode, pos, attr_ver);
848 }
849}
850
851static int fuse_do_readpage(struct file *file, struct page *page)
852{
853 struct inode *inode = page->mapping->host;
854 struct fuse_mount *fm = get_fuse_mount(inode);
855 loff_t pos = page_offset(page);
856 struct fuse_page_desc desc = { .length = PAGE_SIZE };
857 struct fuse_io_args ia = {
858 .ap.args.page_zeroing = true,
859 .ap.args.out_pages = true,
860 .ap.num_pages = 1,
861 .ap.pages = &page,
862 .ap.descs = &desc,
863 };
864 ssize_t res;
865 u64 attr_ver;
866
867 /*
868 * Page writeback can extend beyond the lifetime of the
869 * page-cache page, so make sure we read a properly synced
870 * page.
871 */
872 fuse_wait_on_page_writeback(inode, page->index);
873
874 attr_ver = fuse_get_attr_version(fm->fc);
875
876 /* Don't overflow end offset */
877 if (pos + (desc.length - 1) == LLONG_MAX)
878 desc.length--;
879
880 fuse_read_args_fill(&ia, file, pos, desc.length, FUSE_READ);
881 res = fuse_simple_request(fm, &ia.ap.args);
882 if (res < 0)
883 return res;
884 /*
885 * Short read means EOF. If file size is larger, truncate it
886 */
887 if (res < desc.length)
888 fuse_short_read(inode, attr_ver, res, &ia.ap);
889
890 SetPageUptodate(page);
891
892 return 0;
893}
894
895static int fuse_read_folio(struct file *file, struct folio *folio)
896{
897 struct page *page = &folio->page;
898 struct inode *inode = page->mapping->host;
899 int err;
900
901 err = -EIO;
902 if (fuse_is_bad(inode))
903 goto out;
904
905 err = fuse_do_readpage(file, page);
906 fuse_invalidate_atime(inode);
907 out:
908 unlock_page(page);
909 return err;
910}
911
912static void fuse_readpages_end(struct fuse_mount *fm, struct fuse_args *args,
913 int err)
914{
915 int i;
916 struct fuse_io_args *ia = container_of(args, typeof(*ia), ap.args);
917 struct fuse_args_pages *ap = &ia->ap;
918 size_t count = ia->read.in.size;
919 size_t num_read = args->out_args[0].size;
920 struct address_space *mapping = NULL;
921
922 for (i = 0; mapping == NULL && i < ap->num_pages; i++)
923 mapping = ap->pages[i]->mapping;
924
925 if (mapping) {
926 struct inode *inode = mapping->host;
927
928 /*
929 * Short read means EOF. If file size is larger, truncate it
930 */
931 if (!err && num_read < count)
932 fuse_short_read(inode, ia->read.attr_ver, num_read, ap);
933
934 fuse_invalidate_atime(inode);
935 }
936
937 for (i = 0; i < ap->num_pages; i++) {
938 struct page *page = ap->pages[i];
939
940 if (!err)
941 SetPageUptodate(page);
942 else
943 SetPageError(page);
944 unlock_page(page);
945 put_page(page);
946 }
947 if (ia->ff)
948 fuse_file_put(ia->ff, false);
949
950 fuse_io_free(ia);
951}
952
953static void fuse_send_readpages(struct fuse_io_args *ia, struct file *file)
954{
955 struct fuse_file *ff = file->private_data;
956 struct fuse_mount *fm = ff->fm;
957 struct fuse_args_pages *ap = &ia->ap;
958 loff_t pos = page_offset(ap->pages[0]);
959 size_t count = ap->num_pages << PAGE_SHIFT;
960 ssize_t res;
961 int err;
962
963 ap->args.out_pages = true;
964 ap->args.page_zeroing = true;
965 ap->args.page_replace = true;
966
967 /* Don't overflow end offset */
968 if (pos + (count - 1) == LLONG_MAX) {
969 count--;
970 ap->descs[ap->num_pages - 1].length--;
971 }
972 WARN_ON((loff_t) (pos + count) < 0);
973
974 fuse_read_args_fill(ia, file, pos, count, FUSE_READ);
975 ia->read.attr_ver = fuse_get_attr_version(fm->fc);
976 if (fm->fc->async_read) {
977 ia->ff = fuse_file_get(ff);
978 ap->args.end = fuse_readpages_end;
979 err = fuse_simple_background(fm, &ap->args, GFP_KERNEL);
980 if (!err)
981 return;
982 } else {
983 res = fuse_simple_request(fm, &ap->args);
984 err = res < 0 ? res : 0;
985 }
986 fuse_readpages_end(fm, &ap->args, err);
987}
988
989static void fuse_readahead(struct readahead_control *rac)
990{
991 struct inode *inode = rac->mapping->host;
992 struct fuse_conn *fc = get_fuse_conn(inode);
993 unsigned int i, max_pages, nr_pages = 0;
994
995 if (fuse_is_bad(inode))
996 return;
997
998 max_pages = min_t(unsigned int, fc->max_pages,
999 fc->max_read / PAGE_SIZE);
1000
1001 for (;;) {
1002 struct fuse_io_args *ia;
1003 struct fuse_args_pages *ap;
1004
1005 if (fc->num_background >= fc->congestion_threshold &&
1006 rac->ra->async_size >= readahead_count(rac))
1007 /*
1008 * Congested and only async pages left, so skip the
1009 * rest.
1010 */
1011 break;
1012
1013 nr_pages = readahead_count(rac) - nr_pages;
1014 if (nr_pages > max_pages)
1015 nr_pages = max_pages;
1016 if (nr_pages == 0)
1017 break;
1018 ia = fuse_io_alloc(NULL, nr_pages);
1019 if (!ia)
1020 return;
1021 ap = &ia->ap;
1022 nr_pages = __readahead_batch(rac, ap->pages, nr_pages);
1023 for (i = 0; i < nr_pages; i++) {
1024 fuse_wait_on_page_writeback(inode,
1025 readahead_index(rac) + i);
1026 ap->descs[i].length = PAGE_SIZE;
1027 }
1028 ap->num_pages = nr_pages;
1029 fuse_send_readpages(ia, rac->file);
1030 }
1031}
1032
1033static ssize_t fuse_cache_read_iter(struct kiocb *iocb, struct iov_iter *to)
1034{
1035 struct inode *inode = iocb->ki_filp->f_mapping->host;
1036 struct fuse_conn *fc = get_fuse_conn(inode);
1037
1038 /*
1039 * In auto invalidate mode, always update attributes on read.
1040 * Otherwise, only update if we attempt to read past EOF (to ensure
1041 * i_size is up to date).
1042 */
1043 if (fc->auto_inval_data ||
1044 (iocb->ki_pos + iov_iter_count(to) > i_size_read(inode))) {
1045 int err;
1046 err = fuse_update_attributes(inode, iocb->ki_filp, STATX_SIZE);
1047 if (err)
1048 return err;
1049 }
1050
1051 return generic_file_read_iter(iocb, to);
1052}
1053
1054static void fuse_write_args_fill(struct fuse_io_args *ia, struct fuse_file *ff,
1055 loff_t pos, size_t count)
1056{
1057 struct fuse_args *args = &ia->ap.args;
1058
1059 ia->write.in.fh = ff->fh;
1060 ia->write.in.offset = pos;
1061 ia->write.in.size = count;
1062 args->opcode = FUSE_WRITE;
1063 args->nodeid = ff->nodeid;
1064 args->in_numargs = 2;
1065 if (ff->fm->fc->minor < 9)
1066 args->in_args[0].size = FUSE_COMPAT_WRITE_IN_SIZE;
1067 else
1068 args->in_args[0].size = sizeof(ia->write.in);
1069 args->in_args[0].value = &ia->write.in;
1070 args->in_args[1].size = count;
1071 args->out_numargs = 1;
1072 args->out_args[0].size = sizeof(ia->write.out);
1073 args->out_args[0].value = &ia->write.out;
1074}
1075
1076static unsigned int fuse_write_flags(struct kiocb *iocb)
1077{
1078 unsigned int flags = iocb->ki_filp->f_flags;
1079
1080 if (iocb_is_dsync(iocb))
1081 flags |= O_DSYNC;
1082 if (iocb->ki_flags & IOCB_SYNC)
1083 flags |= O_SYNC;
1084
1085 return flags;
1086}
1087
1088static ssize_t fuse_send_write(struct fuse_io_args *ia, loff_t pos,
1089 size_t count, fl_owner_t owner)
1090{
1091 struct kiocb *iocb = ia->io->iocb;
1092 struct file *file = iocb->ki_filp;
1093 struct fuse_file *ff = file->private_data;
1094 struct fuse_mount *fm = ff->fm;
1095 struct fuse_write_in *inarg = &ia->write.in;
1096 ssize_t err;
1097
1098 fuse_write_args_fill(ia, ff, pos, count);
1099 inarg->flags = fuse_write_flags(iocb);
1100 if (owner != NULL) {
1101 inarg->write_flags |= FUSE_WRITE_LOCKOWNER;
1102 inarg->lock_owner = fuse_lock_owner_id(fm->fc, owner);
1103 }
1104
1105 if (ia->io->async)
1106 return fuse_async_req_send(fm, ia, count);
1107
1108 err = fuse_simple_request(fm, &ia->ap.args);
1109 if (!err && ia->write.out.size > count)
1110 err = -EIO;
1111
1112 return err ?: ia->write.out.size;
1113}
1114
1115bool fuse_write_update_attr(struct inode *inode, loff_t pos, ssize_t written)
1116{
1117 struct fuse_conn *fc = get_fuse_conn(inode);
1118 struct fuse_inode *fi = get_fuse_inode(inode);
1119 bool ret = false;
1120
1121 spin_lock(&fi->lock);
1122 fi->attr_version = atomic64_inc_return(&fc->attr_version);
1123 if (written > 0 && pos > inode->i_size) {
1124 i_size_write(inode, pos);
1125 ret = true;
1126 }
1127 spin_unlock(&fi->lock);
1128
1129 fuse_invalidate_attr_mask(inode, FUSE_STATX_MODSIZE);
1130
1131 return ret;
1132}
1133
1134static ssize_t fuse_send_write_pages(struct fuse_io_args *ia,
1135 struct kiocb *iocb, struct inode *inode,
1136 loff_t pos, size_t count)
1137{
1138 struct fuse_args_pages *ap = &ia->ap;
1139 struct file *file = iocb->ki_filp;
1140 struct fuse_file *ff = file->private_data;
1141 struct fuse_mount *fm = ff->fm;
1142 unsigned int offset, i;
1143 bool short_write;
1144 int err;
1145
1146 for (i = 0; i < ap->num_pages; i++)
1147 fuse_wait_on_page_writeback(inode, ap->pages[i]->index);
1148
1149 fuse_write_args_fill(ia, ff, pos, count);
1150 ia->write.in.flags = fuse_write_flags(iocb);
1151 if (fm->fc->handle_killpriv_v2 && !capable(CAP_FSETID))
1152 ia->write.in.write_flags |= FUSE_WRITE_KILL_SUIDGID;
1153
1154 err = fuse_simple_request(fm, &ap->args);
1155 if (!err && ia->write.out.size > count)
1156 err = -EIO;
1157
1158 short_write = ia->write.out.size < count;
1159 offset = ap->descs[0].offset;
1160 count = ia->write.out.size;
1161 for (i = 0; i < ap->num_pages; i++) {
1162 struct page *page = ap->pages[i];
1163
1164 if (err) {
1165 ClearPageUptodate(page);
1166 } else {
1167 if (count >= PAGE_SIZE - offset)
1168 count -= PAGE_SIZE - offset;
1169 else {
1170 if (short_write)
1171 ClearPageUptodate(page);
1172 count = 0;
1173 }
1174 offset = 0;
1175 }
1176 if (ia->write.page_locked && (i == ap->num_pages - 1))
1177 unlock_page(page);
1178 put_page(page);
1179 }
1180
1181 return err;
1182}
1183
1184static ssize_t fuse_fill_write_pages(struct fuse_io_args *ia,
1185 struct address_space *mapping,
1186 struct iov_iter *ii, loff_t pos,
1187 unsigned int max_pages)
1188{
1189 struct fuse_args_pages *ap = &ia->ap;
1190 struct fuse_conn *fc = get_fuse_conn(mapping->host);
1191 unsigned offset = pos & (PAGE_SIZE - 1);
1192 size_t count = 0;
1193 int err;
1194
1195 ap->args.in_pages = true;
1196 ap->descs[0].offset = offset;
1197
1198 do {
1199 size_t tmp;
1200 struct page *page;
1201 pgoff_t index = pos >> PAGE_SHIFT;
1202 size_t bytes = min_t(size_t, PAGE_SIZE - offset,
1203 iov_iter_count(ii));
1204
1205 bytes = min_t(size_t, bytes, fc->max_write - count);
1206
1207 again:
1208 err = -EFAULT;
1209 if (fault_in_iov_iter_readable(ii, bytes))
1210 break;
1211
1212 err = -ENOMEM;
1213 page = grab_cache_page_write_begin(mapping, index);
1214 if (!page)
1215 break;
1216
1217 if (mapping_writably_mapped(mapping))
1218 flush_dcache_page(page);
1219
1220 tmp = copy_page_from_iter_atomic(page, offset, bytes, ii);
1221 flush_dcache_page(page);
1222
1223 if (!tmp) {
1224 unlock_page(page);
1225 put_page(page);
1226 goto again;
1227 }
1228
1229 err = 0;
1230 ap->pages[ap->num_pages] = page;
1231 ap->descs[ap->num_pages].length = tmp;
1232 ap->num_pages++;
1233
1234 count += tmp;
1235 pos += tmp;
1236 offset += tmp;
1237 if (offset == PAGE_SIZE)
1238 offset = 0;
1239
1240 /* If we copied full page, mark it uptodate */
1241 if (tmp == PAGE_SIZE)
1242 SetPageUptodate(page);
1243
1244 if (PageUptodate(page)) {
1245 unlock_page(page);
1246 } else {
1247 ia->write.page_locked = true;
1248 break;
1249 }
1250 if (!fc->big_writes)
1251 break;
1252 } while (iov_iter_count(ii) && count < fc->max_write &&
1253 ap->num_pages < max_pages && offset == 0);
1254
1255 return count > 0 ? count : err;
1256}
1257
1258static inline unsigned int fuse_wr_pages(loff_t pos, size_t len,
1259 unsigned int max_pages)
1260{
1261 return min_t(unsigned int,
1262 ((pos + len - 1) >> PAGE_SHIFT) -
1263 (pos >> PAGE_SHIFT) + 1,
1264 max_pages);
1265}
1266
1267static ssize_t fuse_perform_write(struct kiocb *iocb, struct iov_iter *ii)
1268{
1269 struct address_space *mapping = iocb->ki_filp->f_mapping;
1270 struct inode *inode = mapping->host;
1271 struct fuse_conn *fc = get_fuse_conn(inode);
1272 struct fuse_inode *fi = get_fuse_inode(inode);
1273 loff_t pos = iocb->ki_pos;
1274 int err = 0;
1275 ssize_t res = 0;
1276
1277 if (inode->i_size < pos + iov_iter_count(ii))
1278 set_bit(FUSE_I_SIZE_UNSTABLE, &fi->state);
1279
1280 do {
1281 ssize_t count;
1282 struct fuse_io_args ia = {};
1283 struct fuse_args_pages *ap = &ia.ap;
1284 unsigned int nr_pages = fuse_wr_pages(pos, iov_iter_count(ii),
1285 fc->max_pages);
1286
1287 ap->pages = fuse_pages_alloc(nr_pages, GFP_KERNEL, &ap->descs);
1288 if (!ap->pages) {
1289 err = -ENOMEM;
1290 break;
1291 }
1292
1293 count = fuse_fill_write_pages(&ia, mapping, ii, pos, nr_pages);
1294 if (count <= 0) {
1295 err = count;
1296 } else {
1297 err = fuse_send_write_pages(&ia, iocb, inode,
1298 pos, count);
1299 if (!err) {
1300 size_t num_written = ia.write.out.size;
1301
1302 res += num_written;
1303 pos += num_written;
1304
1305 /* break out of the loop on short write */
1306 if (num_written != count)
1307 err = -EIO;
1308 }
1309 }
1310 kfree(ap->pages);
1311 } while (!err && iov_iter_count(ii));
1312
1313 fuse_write_update_attr(inode, pos, res);
1314 clear_bit(FUSE_I_SIZE_UNSTABLE, &fi->state);
1315
1316 if (!res)
1317 return err;
1318 iocb->ki_pos += res;
1319 return res;
1320}
1321
1322static bool fuse_io_past_eof(struct kiocb *iocb, struct iov_iter *iter)
1323{
1324 struct inode *inode = file_inode(iocb->ki_filp);
1325
1326 return iocb->ki_pos + iov_iter_count(iter) > i_size_read(inode);
1327}
1328
1329/*
1330 * @return true if an exclusive lock for direct IO writes is needed
1331 */
1332static bool fuse_dio_wr_exclusive_lock(struct kiocb *iocb, struct iov_iter *from)
1333{
1334 struct file *file = iocb->ki_filp;
1335 struct fuse_file *ff = file->private_data;
1336 struct inode *inode = file_inode(iocb->ki_filp);
1337 struct fuse_inode *fi = get_fuse_inode(inode);
1338
1339 /* Server side has to advise that it supports parallel dio writes. */
1340 if (!(ff->open_flags & FOPEN_PARALLEL_DIRECT_WRITES))
1341 return true;
1342
1343 /*
1344 * Append will need to know the eventual EOF - always needs an
1345 * exclusive lock.
1346 */
1347 if (iocb->ki_flags & IOCB_APPEND)
1348 return true;
1349
1350 /* shared locks are not allowed with parallel page cache IO */
1351 if (test_bit(FUSE_I_CACHE_IO_MODE, &fi->state))
1352 return false;
1353
1354 /* Parallel dio beyond EOF is not supported, at least for now. */
1355 if (fuse_io_past_eof(iocb, from))
1356 return true;
1357
1358 return false;
1359}
1360
1361static void fuse_dio_lock(struct kiocb *iocb, struct iov_iter *from,
1362 bool *exclusive)
1363{
1364 struct inode *inode = file_inode(iocb->ki_filp);
1365 struct fuse_inode *fi = get_fuse_inode(inode);
1366
1367 *exclusive = fuse_dio_wr_exclusive_lock(iocb, from);
1368 if (*exclusive) {
1369 inode_lock(inode);
1370 } else {
1371 inode_lock_shared(inode);
1372 /*
1373 * New parallal dio allowed only if inode is not in caching
1374 * mode and denies new opens in caching mode. This check
1375 * should be performed only after taking shared inode lock.
1376 * Previous past eof check was without inode lock and might
1377 * have raced, so check it again.
1378 */
1379 if (fuse_io_past_eof(iocb, from) ||
1380 fuse_inode_uncached_io_start(fi, NULL) != 0) {
1381 inode_unlock_shared(inode);
1382 inode_lock(inode);
1383 *exclusive = true;
1384 }
1385 }
1386}
1387
1388static void fuse_dio_unlock(struct kiocb *iocb, bool exclusive)
1389{
1390 struct inode *inode = file_inode(iocb->ki_filp);
1391 struct fuse_inode *fi = get_fuse_inode(inode);
1392
1393 if (exclusive) {
1394 inode_unlock(inode);
1395 } else {
1396 /* Allow opens in caching mode after last parallel dio end */
1397 fuse_inode_uncached_io_end(fi);
1398 inode_unlock_shared(inode);
1399 }
1400}
1401
1402static ssize_t fuse_cache_write_iter(struct kiocb *iocb, struct iov_iter *from)
1403{
1404 struct file *file = iocb->ki_filp;
1405 struct address_space *mapping = file->f_mapping;
1406 ssize_t written = 0;
1407 struct inode *inode = mapping->host;
1408 ssize_t err, count;
1409 struct fuse_conn *fc = get_fuse_conn(inode);
1410
1411 if (fc->writeback_cache) {
1412 /* Update size (EOF optimization) and mode (SUID clearing) */
1413 err = fuse_update_attributes(mapping->host, file,
1414 STATX_SIZE | STATX_MODE);
1415 if (err)
1416 return err;
1417
1418 if (fc->handle_killpriv_v2 &&
1419 setattr_should_drop_suidgid(&nop_mnt_idmap,
1420 file_inode(file))) {
1421 goto writethrough;
1422 }
1423
1424 return generic_file_write_iter(iocb, from);
1425 }
1426
1427writethrough:
1428 inode_lock(inode);
1429
1430 err = count = generic_write_checks(iocb, from);
1431 if (err <= 0)
1432 goto out;
1433
1434 task_io_account_write(count);
1435
1436 err = file_remove_privs(file);
1437 if (err)
1438 goto out;
1439
1440 err = file_update_time(file);
1441 if (err)
1442 goto out;
1443
1444 if (iocb->ki_flags & IOCB_DIRECT) {
1445 written = generic_file_direct_write(iocb, from);
1446 if (written < 0 || !iov_iter_count(from))
1447 goto out;
1448 written = direct_write_fallback(iocb, from, written,
1449 fuse_perform_write(iocb, from));
1450 } else {
1451 written = fuse_perform_write(iocb, from);
1452 }
1453out:
1454 inode_unlock(inode);
1455 if (written > 0)
1456 written = generic_write_sync(iocb, written);
1457
1458 return written ? written : err;
1459}
1460
1461static inline unsigned long fuse_get_user_addr(const struct iov_iter *ii)
1462{
1463 return (unsigned long)iter_iov(ii)->iov_base + ii->iov_offset;
1464}
1465
1466static inline size_t fuse_get_frag_size(const struct iov_iter *ii,
1467 size_t max_size)
1468{
1469 return min(iov_iter_single_seg_count(ii), max_size);
1470}
1471
1472static int fuse_get_user_pages(struct fuse_args_pages *ap, struct iov_iter *ii,
1473 size_t *nbytesp, int write,
1474 unsigned int max_pages)
1475{
1476 size_t nbytes = 0; /* # bytes already packed in req */
1477 ssize_t ret = 0;
1478
1479 /* Special case for kernel I/O: can copy directly into the buffer */
1480 if (iov_iter_is_kvec(ii)) {
1481 unsigned long user_addr = fuse_get_user_addr(ii);
1482 size_t frag_size = fuse_get_frag_size(ii, *nbytesp);
1483
1484 if (write)
1485 ap->args.in_args[1].value = (void *) user_addr;
1486 else
1487 ap->args.out_args[0].value = (void *) user_addr;
1488
1489 iov_iter_advance(ii, frag_size);
1490 *nbytesp = frag_size;
1491 return 0;
1492 }
1493
1494 while (nbytes < *nbytesp && ap->num_pages < max_pages) {
1495 unsigned npages;
1496 size_t start;
1497 struct page **pt_pages;
1498
1499 pt_pages = &ap->pages[ap->num_pages];
1500 ret = iov_iter_extract_pages(ii, &pt_pages,
1501 *nbytesp - nbytes,
1502 max_pages - ap->num_pages,
1503 0, &start);
1504 if (ret < 0)
1505 break;
1506
1507 nbytes += ret;
1508
1509 ret += start;
1510 npages = DIV_ROUND_UP(ret, PAGE_SIZE);
1511
1512 ap->descs[ap->num_pages].offset = start;
1513 fuse_page_descs_length_init(ap->descs, ap->num_pages, npages);
1514
1515 ap->num_pages += npages;
1516 ap->descs[ap->num_pages - 1].length -=
1517 (PAGE_SIZE - ret) & (PAGE_SIZE - 1);
1518 }
1519
1520 ap->args.is_pinned = iov_iter_extract_will_pin(ii);
1521 ap->args.user_pages = true;
1522 if (write)
1523 ap->args.in_pages = true;
1524 else
1525 ap->args.out_pages = true;
1526
1527 *nbytesp = nbytes;
1528
1529 return ret < 0 ? ret : 0;
1530}
1531
1532ssize_t fuse_direct_io(struct fuse_io_priv *io, struct iov_iter *iter,
1533 loff_t *ppos, int flags)
1534{
1535 int write = flags & FUSE_DIO_WRITE;
1536 int cuse = flags & FUSE_DIO_CUSE;
1537 struct file *file = io->iocb->ki_filp;
1538 struct address_space *mapping = file->f_mapping;
1539 struct inode *inode = mapping->host;
1540 struct fuse_file *ff = file->private_data;
1541 struct fuse_conn *fc = ff->fm->fc;
1542 size_t nmax = write ? fc->max_write : fc->max_read;
1543 loff_t pos = *ppos;
1544 size_t count = iov_iter_count(iter);
1545 pgoff_t idx_from = pos >> PAGE_SHIFT;
1546 pgoff_t idx_to = (pos + count - 1) >> PAGE_SHIFT;
1547 ssize_t res = 0;
1548 int err = 0;
1549 struct fuse_io_args *ia;
1550 unsigned int max_pages;
1551 bool fopen_direct_io = ff->open_flags & FOPEN_DIRECT_IO;
1552
1553 max_pages = iov_iter_npages(iter, fc->max_pages);
1554 ia = fuse_io_alloc(io, max_pages);
1555 if (!ia)
1556 return -ENOMEM;
1557
1558 if (fopen_direct_io && fc->direct_io_allow_mmap) {
1559 res = filemap_write_and_wait_range(mapping, pos, pos + count - 1);
1560 if (res) {
1561 fuse_io_free(ia);
1562 return res;
1563 }
1564 }
1565 if (!cuse && fuse_range_is_writeback(inode, idx_from, idx_to)) {
1566 if (!write)
1567 inode_lock(inode);
1568 fuse_sync_writes(inode);
1569 if (!write)
1570 inode_unlock(inode);
1571 }
1572
1573 if (fopen_direct_io && write) {
1574 res = invalidate_inode_pages2_range(mapping, idx_from, idx_to);
1575 if (res) {
1576 fuse_io_free(ia);
1577 return res;
1578 }
1579 }
1580
1581 io->should_dirty = !write && user_backed_iter(iter);
1582 while (count) {
1583 ssize_t nres;
1584 fl_owner_t owner = current->files;
1585 size_t nbytes = min(count, nmax);
1586
1587 err = fuse_get_user_pages(&ia->ap, iter, &nbytes, write,
1588 max_pages);
1589 if (err && !nbytes)
1590 break;
1591
1592 if (write) {
1593 if (!capable(CAP_FSETID))
1594 ia->write.in.write_flags |= FUSE_WRITE_KILL_SUIDGID;
1595
1596 nres = fuse_send_write(ia, pos, nbytes, owner);
1597 } else {
1598 nres = fuse_send_read(ia, pos, nbytes, owner);
1599 }
1600
1601 if (!io->async || nres < 0) {
1602 fuse_release_user_pages(&ia->ap, io->should_dirty);
1603 fuse_io_free(ia);
1604 }
1605 ia = NULL;
1606 if (nres < 0) {
1607 iov_iter_revert(iter, nbytes);
1608 err = nres;
1609 break;
1610 }
1611 WARN_ON(nres > nbytes);
1612
1613 count -= nres;
1614 res += nres;
1615 pos += nres;
1616 if (nres != nbytes) {
1617 iov_iter_revert(iter, nbytes - nres);
1618 break;
1619 }
1620 if (count) {
1621 max_pages = iov_iter_npages(iter, fc->max_pages);
1622 ia = fuse_io_alloc(io, max_pages);
1623 if (!ia)
1624 break;
1625 }
1626 }
1627 if (ia)
1628 fuse_io_free(ia);
1629 if (res > 0)
1630 *ppos = pos;
1631
1632 return res > 0 ? res : err;
1633}
1634EXPORT_SYMBOL_GPL(fuse_direct_io);
1635
1636static ssize_t __fuse_direct_read(struct fuse_io_priv *io,
1637 struct iov_iter *iter,
1638 loff_t *ppos)
1639{
1640 ssize_t res;
1641 struct inode *inode = file_inode(io->iocb->ki_filp);
1642
1643 res = fuse_direct_io(io, iter, ppos, 0);
1644
1645 fuse_invalidate_atime(inode);
1646
1647 return res;
1648}
1649
1650static ssize_t fuse_direct_IO(struct kiocb *iocb, struct iov_iter *iter);
1651
1652static ssize_t fuse_direct_read_iter(struct kiocb *iocb, struct iov_iter *to)
1653{
1654 ssize_t res;
1655
1656 if (!is_sync_kiocb(iocb) && iocb->ki_flags & IOCB_DIRECT) {
1657 res = fuse_direct_IO(iocb, to);
1658 } else {
1659 struct fuse_io_priv io = FUSE_IO_PRIV_SYNC(iocb);
1660
1661 res = __fuse_direct_read(&io, to, &iocb->ki_pos);
1662 }
1663
1664 return res;
1665}
1666
1667static ssize_t fuse_direct_write_iter(struct kiocb *iocb, struct iov_iter *from)
1668{
1669 struct inode *inode = file_inode(iocb->ki_filp);
1670 struct fuse_io_priv io = FUSE_IO_PRIV_SYNC(iocb);
1671 ssize_t res;
1672 bool exclusive;
1673
1674 fuse_dio_lock(iocb, from, &exclusive);
1675 res = generic_write_checks(iocb, from);
1676 if (res > 0) {
1677 task_io_account_write(res);
1678 if (!is_sync_kiocb(iocb) && iocb->ki_flags & IOCB_DIRECT) {
1679 res = fuse_direct_IO(iocb, from);
1680 } else {
1681 res = fuse_direct_io(&io, from, &iocb->ki_pos,
1682 FUSE_DIO_WRITE);
1683 fuse_write_update_attr(inode, iocb->ki_pos, res);
1684 }
1685 }
1686 fuse_dio_unlock(iocb, exclusive);
1687
1688 return res;
1689}
1690
1691static ssize_t fuse_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
1692{
1693 struct file *file = iocb->ki_filp;
1694 struct fuse_file *ff = file->private_data;
1695 struct inode *inode = file_inode(file);
1696
1697 if (fuse_is_bad(inode))
1698 return -EIO;
1699
1700 if (FUSE_IS_DAX(inode))
1701 return fuse_dax_read_iter(iocb, to);
1702
1703 /* FOPEN_DIRECT_IO overrides FOPEN_PASSTHROUGH */
1704 if (ff->open_flags & FOPEN_DIRECT_IO)
1705 return fuse_direct_read_iter(iocb, to);
1706 else if (fuse_file_passthrough(ff))
1707 return fuse_passthrough_read_iter(iocb, to);
1708 else
1709 return fuse_cache_read_iter(iocb, to);
1710}
1711
1712static ssize_t fuse_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
1713{
1714 struct file *file = iocb->ki_filp;
1715 struct fuse_file *ff = file->private_data;
1716 struct inode *inode = file_inode(file);
1717
1718 if (fuse_is_bad(inode))
1719 return -EIO;
1720
1721 if (FUSE_IS_DAX(inode))
1722 return fuse_dax_write_iter(iocb, from);
1723
1724 /* FOPEN_DIRECT_IO overrides FOPEN_PASSTHROUGH */
1725 if (ff->open_flags & FOPEN_DIRECT_IO)
1726 return fuse_direct_write_iter(iocb, from);
1727 else if (fuse_file_passthrough(ff))
1728 return fuse_passthrough_write_iter(iocb, from);
1729 else
1730 return fuse_cache_write_iter(iocb, from);
1731}
1732
1733static ssize_t fuse_splice_read(struct file *in, loff_t *ppos,
1734 struct pipe_inode_info *pipe, size_t len,
1735 unsigned int flags)
1736{
1737 struct fuse_file *ff = in->private_data;
1738
1739 /* FOPEN_DIRECT_IO overrides FOPEN_PASSTHROUGH */
1740 if (fuse_file_passthrough(ff) && !(ff->open_flags & FOPEN_DIRECT_IO))
1741 return fuse_passthrough_splice_read(in, ppos, pipe, len, flags);
1742 else
1743 return filemap_splice_read(in, ppos, pipe, len, flags);
1744}
1745
1746static ssize_t fuse_splice_write(struct pipe_inode_info *pipe, struct file *out,
1747 loff_t *ppos, size_t len, unsigned int flags)
1748{
1749 struct fuse_file *ff = out->private_data;
1750
1751 /* FOPEN_DIRECT_IO overrides FOPEN_PASSTHROUGH */
1752 if (fuse_file_passthrough(ff) && !(ff->open_flags & FOPEN_DIRECT_IO))
1753 return fuse_passthrough_splice_write(pipe, out, ppos, len, flags);
1754 else
1755 return iter_file_splice_write(pipe, out, ppos, len, flags);
1756}
1757
1758static void fuse_writepage_free(struct fuse_writepage_args *wpa)
1759{
1760 struct fuse_args_pages *ap = &wpa->ia.ap;
1761 int i;
1762
1763 if (wpa->bucket)
1764 fuse_sync_bucket_dec(wpa->bucket);
1765
1766 for (i = 0; i < ap->num_pages; i++)
1767 __free_page(ap->pages[i]);
1768
1769 if (wpa->ia.ff)
1770 fuse_file_put(wpa->ia.ff, false);
1771
1772 kfree(ap->pages);
1773 kfree(wpa);
1774}
1775
1776static void fuse_writepage_finish(struct fuse_mount *fm,
1777 struct fuse_writepage_args *wpa)
1778{
1779 struct fuse_args_pages *ap = &wpa->ia.ap;
1780 struct inode *inode = wpa->inode;
1781 struct fuse_inode *fi = get_fuse_inode(inode);
1782 struct backing_dev_info *bdi = inode_to_bdi(inode);
1783 int i;
1784
1785 for (i = 0; i < ap->num_pages; i++) {
1786 dec_wb_stat(&bdi->wb, WB_WRITEBACK);
1787 dec_node_page_state(ap->pages[i], NR_WRITEBACK_TEMP);
1788 wb_writeout_inc(&bdi->wb);
1789 }
1790 wake_up(&fi->page_waitq);
1791}
1792
1793/* Called under fi->lock, may release and reacquire it */
1794static void fuse_send_writepage(struct fuse_mount *fm,
1795 struct fuse_writepage_args *wpa, loff_t size)
1796__releases(fi->lock)
1797__acquires(fi->lock)
1798{
1799 struct fuse_writepage_args *aux, *next;
1800 struct fuse_inode *fi = get_fuse_inode(wpa->inode);
1801 struct fuse_write_in *inarg = &wpa->ia.write.in;
1802 struct fuse_args *args = &wpa->ia.ap.args;
1803 __u64 data_size = wpa->ia.ap.num_pages * PAGE_SIZE;
1804 int err;
1805
1806 fi->writectr++;
1807 if (inarg->offset + data_size <= size) {
1808 inarg->size = data_size;
1809 } else if (inarg->offset < size) {
1810 inarg->size = size - inarg->offset;
1811 } else {
1812 /* Got truncated off completely */
1813 goto out_free;
1814 }
1815
1816 args->in_args[1].size = inarg->size;
1817 args->force = true;
1818 args->nocreds = true;
1819
1820 err = fuse_simple_background(fm, args, GFP_ATOMIC);
1821 if (err == -ENOMEM) {
1822 spin_unlock(&fi->lock);
1823 err = fuse_simple_background(fm, args, GFP_NOFS | __GFP_NOFAIL);
1824 spin_lock(&fi->lock);
1825 }
1826
1827 /* Fails on broken connection only */
1828 if (unlikely(err))
1829 goto out_free;
1830
1831 return;
1832
1833 out_free:
1834 fi->writectr--;
1835 rb_erase(&wpa->writepages_entry, &fi->writepages);
1836 fuse_writepage_finish(fm, wpa);
1837 spin_unlock(&fi->lock);
1838
1839 /* After fuse_writepage_finish() aux request list is private */
1840 for (aux = wpa->next; aux; aux = next) {
1841 next = aux->next;
1842 aux->next = NULL;
1843 fuse_writepage_free(aux);
1844 }
1845
1846 fuse_writepage_free(wpa);
1847 spin_lock(&fi->lock);
1848}
1849
1850/*
1851 * If fi->writectr is positive (no truncate or fsync going on) send
1852 * all queued writepage requests.
1853 *
1854 * Called with fi->lock
1855 */
1856void fuse_flush_writepages(struct inode *inode)
1857__releases(fi->lock)
1858__acquires(fi->lock)
1859{
1860 struct fuse_mount *fm = get_fuse_mount(inode);
1861 struct fuse_inode *fi = get_fuse_inode(inode);
1862 loff_t crop = i_size_read(inode);
1863 struct fuse_writepage_args *wpa;
1864
1865 while (fi->writectr >= 0 && !list_empty(&fi->queued_writes)) {
1866 wpa = list_entry(fi->queued_writes.next,
1867 struct fuse_writepage_args, queue_entry);
1868 list_del_init(&wpa->queue_entry);
1869 fuse_send_writepage(fm, wpa, crop);
1870 }
1871}
1872
1873static struct fuse_writepage_args *fuse_insert_writeback(struct rb_root *root,
1874 struct fuse_writepage_args *wpa)
1875{
1876 pgoff_t idx_from = wpa->ia.write.in.offset >> PAGE_SHIFT;
1877 pgoff_t idx_to = idx_from + wpa->ia.ap.num_pages - 1;
1878 struct rb_node **p = &root->rb_node;
1879 struct rb_node *parent = NULL;
1880
1881 WARN_ON(!wpa->ia.ap.num_pages);
1882 while (*p) {
1883 struct fuse_writepage_args *curr;
1884 pgoff_t curr_index;
1885
1886 parent = *p;
1887 curr = rb_entry(parent, struct fuse_writepage_args,
1888 writepages_entry);
1889 WARN_ON(curr->inode != wpa->inode);
1890 curr_index = curr->ia.write.in.offset >> PAGE_SHIFT;
1891
1892 if (idx_from >= curr_index + curr->ia.ap.num_pages)
1893 p = &(*p)->rb_right;
1894 else if (idx_to < curr_index)
1895 p = &(*p)->rb_left;
1896 else
1897 return curr;
1898 }
1899
1900 rb_link_node(&wpa->writepages_entry, parent, p);
1901 rb_insert_color(&wpa->writepages_entry, root);
1902 return NULL;
1903}
1904
1905static void tree_insert(struct rb_root *root, struct fuse_writepage_args *wpa)
1906{
1907 WARN_ON(fuse_insert_writeback(root, wpa));
1908}
1909
1910static void fuse_writepage_end(struct fuse_mount *fm, struct fuse_args *args,
1911 int error)
1912{
1913 struct fuse_writepage_args *wpa =
1914 container_of(args, typeof(*wpa), ia.ap.args);
1915 struct inode *inode = wpa->inode;
1916 struct fuse_inode *fi = get_fuse_inode(inode);
1917 struct fuse_conn *fc = get_fuse_conn(inode);
1918
1919 mapping_set_error(inode->i_mapping, error);
1920 /*
1921 * A writeback finished and this might have updated mtime/ctime on
1922 * server making local mtime/ctime stale. Hence invalidate attrs.
1923 * Do this only if writeback_cache is not enabled. If writeback_cache
1924 * is enabled, we trust local ctime/mtime.
1925 */
1926 if (!fc->writeback_cache)
1927 fuse_invalidate_attr_mask(inode, FUSE_STATX_MODIFY);
1928 spin_lock(&fi->lock);
1929 rb_erase(&wpa->writepages_entry, &fi->writepages);
1930 while (wpa->next) {
1931 struct fuse_mount *fm = get_fuse_mount(inode);
1932 struct fuse_write_in *inarg = &wpa->ia.write.in;
1933 struct fuse_writepage_args *next = wpa->next;
1934
1935 wpa->next = next->next;
1936 next->next = NULL;
1937 next->ia.ff = fuse_file_get(wpa->ia.ff);
1938 tree_insert(&fi->writepages, next);
1939
1940 /*
1941 * Skip fuse_flush_writepages() to make it easy to crop requests
1942 * based on primary request size.
1943 *
1944 * 1st case (trivial): there are no concurrent activities using
1945 * fuse_set/release_nowrite. Then we're on safe side because
1946 * fuse_flush_writepages() would call fuse_send_writepage()
1947 * anyway.
1948 *
1949 * 2nd case: someone called fuse_set_nowrite and it is waiting
1950 * now for completion of all in-flight requests. This happens
1951 * rarely and no more than once per page, so this should be
1952 * okay.
1953 *
1954 * 3rd case: someone (e.g. fuse_do_setattr()) is in the middle
1955 * of fuse_set_nowrite..fuse_release_nowrite section. The fact
1956 * that fuse_set_nowrite returned implies that all in-flight
1957 * requests were completed along with all of their secondary
1958 * requests. Further primary requests are blocked by negative
1959 * writectr. Hence there cannot be any in-flight requests and
1960 * no invocations of fuse_writepage_end() while we're in
1961 * fuse_set_nowrite..fuse_release_nowrite section.
1962 */
1963 fuse_send_writepage(fm, next, inarg->offset + inarg->size);
1964 }
1965 fi->writectr--;
1966 fuse_writepage_finish(fm, wpa);
1967 spin_unlock(&fi->lock);
1968 fuse_writepage_free(wpa);
1969}
1970
1971static struct fuse_file *__fuse_write_file_get(struct fuse_inode *fi)
1972{
1973 struct fuse_file *ff;
1974
1975 spin_lock(&fi->lock);
1976 ff = list_first_entry_or_null(&fi->write_files, struct fuse_file,
1977 write_entry);
1978 if (ff)
1979 fuse_file_get(ff);
1980 spin_unlock(&fi->lock);
1981
1982 return ff;
1983}
1984
1985static struct fuse_file *fuse_write_file_get(struct fuse_inode *fi)
1986{
1987 struct fuse_file *ff = __fuse_write_file_get(fi);
1988 WARN_ON(!ff);
1989 return ff;
1990}
1991
1992int fuse_write_inode(struct inode *inode, struct writeback_control *wbc)
1993{
1994 struct fuse_inode *fi = get_fuse_inode(inode);
1995 struct fuse_file *ff;
1996 int err;
1997
1998 /*
1999 * Inode is always written before the last reference is dropped and
2000 * hence this should not be reached from reclaim.
2001 *
2002 * Writing back the inode from reclaim can deadlock if the request
2003 * processing itself needs an allocation. Allocations triggering
2004 * reclaim while serving a request can't be prevented, because it can
2005 * involve any number of unrelated userspace processes.
2006 */
2007 WARN_ON(wbc->for_reclaim);
2008
2009 ff = __fuse_write_file_get(fi);
2010 err = fuse_flush_times(inode, ff);
2011 if (ff)
2012 fuse_file_put(ff, false);
2013
2014 return err;
2015}
2016
2017static struct fuse_writepage_args *fuse_writepage_args_alloc(void)
2018{
2019 struct fuse_writepage_args *wpa;
2020 struct fuse_args_pages *ap;
2021
2022 wpa = kzalloc(sizeof(*wpa), GFP_NOFS);
2023 if (wpa) {
2024 ap = &wpa->ia.ap;
2025 ap->num_pages = 0;
2026 ap->pages = fuse_pages_alloc(1, GFP_NOFS, &ap->descs);
2027 if (!ap->pages) {
2028 kfree(wpa);
2029 wpa = NULL;
2030 }
2031 }
2032 return wpa;
2033
2034}
2035
2036static void fuse_writepage_add_to_bucket(struct fuse_conn *fc,
2037 struct fuse_writepage_args *wpa)
2038{
2039 if (!fc->sync_fs)
2040 return;
2041
2042 rcu_read_lock();
2043 /* Prevent resurrection of dead bucket in unlikely race with syncfs */
2044 do {
2045 wpa->bucket = rcu_dereference(fc->curr_bucket);
2046 } while (unlikely(!atomic_inc_not_zero(&wpa->bucket->count)));
2047 rcu_read_unlock();
2048}
2049
2050static int fuse_writepage_locked(struct folio *folio)
2051{
2052 struct address_space *mapping = folio->mapping;
2053 struct inode *inode = mapping->host;
2054 struct fuse_conn *fc = get_fuse_conn(inode);
2055 struct fuse_inode *fi = get_fuse_inode(inode);
2056 struct fuse_writepage_args *wpa;
2057 struct fuse_args_pages *ap;
2058 struct folio *tmp_folio;
2059 int error = -ENOMEM;
2060
2061 folio_start_writeback(folio);
2062
2063 wpa = fuse_writepage_args_alloc();
2064 if (!wpa)
2065 goto err;
2066 ap = &wpa->ia.ap;
2067
2068 tmp_folio = folio_alloc(GFP_NOFS | __GFP_HIGHMEM, 0);
2069 if (!tmp_folio)
2070 goto err_free;
2071
2072 error = -EIO;
2073 wpa->ia.ff = fuse_write_file_get(fi);
2074 if (!wpa->ia.ff)
2075 goto err_nofile;
2076
2077 fuse_writepage_add_to_bucket(fc, wpa);
2078 fuse_write_args_fill(&wpa->ia, wpa->ia.ff, folio_pos(folio), 0);
2079
2080 folio_copy(tmp_folio, folio);
2081 wpa->ia.write.in.write_flags |= FUSE_WRITE_CACHE;
2082 wpa->next = NULL;
2083 ap->args.in_pages = true;
2084 ap->num_pages = 1;
2085 ap->pages[0] = &tmp_folio->page;
2086 ap->descs[0].offset = 0;
2087 ap->descs[0].length = PAGE_SIZE;
2088 ap->args.end = fuse_writepage_end;
2089 wpa->inode = inode;
2090
2091 inc_wb_stat(&inode_to_bdi(inode)->wb, WB_WRITEBACK);
2092 node_stat_add_folio(tmp_folio, NR_WRITEBACK_TEMP);
2093
2094 spin_lock(&fi->lock);
2095 tree_insert(&fi->writepages, wpa);
2096 list_add_tail(&wpa->queue_entry, &fi->queued_writes);
2097 fuse_flush_writepages(inode);
2098 spin_unlock(&fi->lock);
2099
2100 folio_end_writeback(folio);
2101
2102 return 0;
2103
2104err_nofile:
2105 folio_put(tmp_folio);
2106err_free:
2107 kfree(wpa);
2108err:
2109 mapping_set_error(folio->mapping, error);
2110 folio_end_writeback(folio);
2111 return error;
2112}
2113
2114struct fuse_fill_wb_data {
2115 struct fuse_writepage_args *wpa;
2116 struct fuse_file *ff;
2117 struct inode *inode;
2118 struct page **orig_pages;
2119 unsigned int max_pages;
2120};
2121
2122static bool fuse_pages_realloc(struct fuse_fill_wb_data *data)
2123{
2124 struct fuse_args_pages *ap = &data->wpa->ia.ap;
2125 struct fuse_conn *fc = get_fuse_conn(data->inode);
2126 struct page **pages;
2127 struct fuse_page_desc *descs;
2128 unsigned int npages = min_t(unsigned int,
2129 max_t(unsigned int, data->max_pages * 2,
2130 FUSE_DEFAULT_MAX_PAGES_PER_REQ),
2131 fc->max_pages);
2132 WARN_ON(npages <= data->max_pages);
2133
2134 pages = fuse_pages_alloc(npages, GFP_NOFS, &descs);
2135 if (!pages)
2136 return false;
2137
2138 memcpy(pages, ap->pages, sizeof(struct page *) * ap->num_pages);
2139 memcpy(descs, ap->descs, sizeof(struct fuse_page_desc) * ap->num_pages);
2140 kfree(ap->pages);
2141 ap->pages = pages;
2142 ap->descs = descs;
2143 data->max_pages = npages;
2144
2145 return true;
2146}
2147
2148static void fuse_writepages_send(struct fuse_fill_wb_data *data)
2149{
2150 struct fuse_writepage_args *wpa = data->wpa;
2151 struct inode *inode = data->inode;
2152 struct fuse_inode *fi = get_fuse_inode(inode);
2153 int num_pages = wpa->ia.ap.num_pages;
2154 int i;
2155
2156 wpa->ia.ff = fuse_file_get(data->ff);
2157 spin_lock(&fi->lock);
2158 list_add_tail(&wpa->queue_entry, &fi->queued_writes);
2159 fuse_flush_writepages(inode);
2160 spin_unlock(&fi->lock);
2161
2162 for (i = 0; i < num_pages; i++)
2163 end_page_writeback(data->orig_pages[i]);
2164}
2165
2166/*
2167 * Check under fi->lock if the page is under writeback, and insert it onto the
2168 * rb_tree if not. Otherwise iterate auxiliary write requests, to see if there's
2169 * one already added for a page at this offset. If there's none, then insert
2170 * this new request onto the auxiliary list, otherwise reuse the existing one by
2171 * swapping the new temp page with the old one.
2172 */
2173static bool fuse_writepage_add(struct fuse_writepage_args *new_wpa,
2174 struct page *page)
2175{
2176 struct fuse_inode *fi = get_fuse_inode(new_wpa->inode);
2177 struct fuse_writepage_args *tmp;
2178 struct fuse_writepage_args *old_wpa;
2179 struct fuse_args_pages *new_ap = &new_wpa->ia.ap;
2180
2181 WARN_ON(new_ap->num_pages != 0);
2182 new_ap->num_pages = 1;
2183
2184 spin_lock(&fi->lock);
2185 old_wpa = fuse_insert_writeback(&fi->writepages, new_wpa);
2186 if (!old_wpa) {
2187 spin_unlock(&fi->lock);
2188 return true;
2189 }
2190
2191 for (tmp = old_wpa->next; tmp; tmp = tmp->next) {
2192 pgoff_t curr_index;
2193
2194 WARN_ON(tmp->inode != new_wpa->inode);
2195 curr_index = tmp->ia.write.in.offset >> PAGE_SHIFT;
2196 if (curr_index == page->index) {
2197 WARN_ON(tmp->ia.ap.num_pages != 1);
2198 swap(tmp->ia.ap.pages[0], new_ap->pages[0]);
2199 break;
2200 }
2201 }
2202
2203 if (!tmp) {
2204 new_wpa->next = old_wpa->next;
2205 old_wpa->next = new_wpa;
2206 }
2207
2208 spin_unlock(&fi->lock);
2209
2210 if (tmp) {
2211 struct backing_dev_info *bdi = inode_to_bdi(new_wpa->inode);
2212
2213 dec_wb_stat(&bdi->wb, WB_WRITEBACK);
2214 dec_node_page_state(new_ap->pages[0], NR_WRITEBACK_TEMP);
2215 wb_writeout_inc(&bdi->wb);
2216 fuse_writepage_free(new_wpa);
2217 }
2218
2219 return false;
2220}
2221
2222static bool fuse_writepage_need_send(struct fuse_conn *fc, struct page *page,
2223 struct fuse_args_pages *ap,
2224 struct fuse_fill_wb_data *data)
2225{
2226 WARN_ON(!ap->num_pages);
2227
2228 /*
2229 * Being under writeback is unlikely but possible. For example direct
2230 * read to an mmaped fuse file will set the page dirty twice; once when
2231 * the pages are faulted with get_user_pages(), and then after the read
2232 * completed.
2233 */
2234 if (fuse_page_is_writeback(data->inode, page->index))
2235 return true;
2236
2237 /* Reached max pages */
2238 if (ap->num_pages == fc->max_pages)
2239 return true;
2240
2241 /* Reached max write bytes */
2242 if ((ap->num_pages + 1) * PAGE_SIZE > fc->max_write)
2243 return true;
2244
2245 /* Discontinuity */
2246 if (data->orig_pages[ap->num_pages - 1]->index + 1 != page->index)
2247 return true;
2248
2249 /* Need to grow the pages array? If so, did the expansion fail? */
2250 if (ap->num_pages == data->max_pages && !fuse_pages_realloc(data))
2251 return true;
2252
2253 return false;
2254}
2255
2256static int fuse_writepages_fill(struct folio *folio,
2257 struct writeback_control *wbc, void *_data)
2258{
2259 struct fuse_fill_wb_data *data = _data;
2260 struct fuse_writepage_args *wpa = data->wpa;
2261 struct fuse_args_pages *ap = &wpa->ia.ap;
2262 struct inode *inode = data->inode;
2263 struct fuse_inode *fi = get_fuse_inode(inode);
2264 struct fuse_conn *fc = get_fuse_conn(inode);
2265 struct page *tmp_page;
2266 int err;
2267
2268 if (!data->ff) {
2269 err = -EIO;
2270 data->ff = fuse_write_file_get(fi);
2271 if (!data->ff)
2272 goto out_unlock;
2273 }
2274
2275 if (wpa && fuse_writepage_need_send(fc, &folio->page, ap, data)) {
2276 fuse_writepages_send(data);
2277 data->wpa = NULL;
2278 }
2279
2280 err = -ENOMEM;
2281 tmp_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
2282 if (!tmp_page)
2283 goto out_unlock;
2284
2285 /*
2286 * The page must not be redirtied until the writeout is completed
2287 * (i.e. userspace has sent a reply to the write request). Otherwise
2288 * there could be more than one temporary page instance for each real
2289 * page.
2290 *
2291 * This is ensured by holding the page lock in page_mkwrite() while
2292 * checking fuse_page_is_writeback(). We already hold the page lock
2293 * since clear_page_dirty_for_io() and keep it held until we add the
2294 * request to the fi->writepages list and increment ap->num_pages.
2295 * After this fuse_page_is_writeback() will indicate that the page is
2296 * under writeback, so we can release the page lock.
2297 */
2298 if (data->wpa == NULL) {
2299 err = -ENOMEM;
2300 wpa = fuse_writepage_args_alloc();
2301 if (!wpa) {
2302 __free_page(tmp_page);
2303 goto out_unlock;
2304 }
2305 fuse_writepage_add_to_bucket(fc, wpa);
2306
2307 data->max_pages = 1;
2308
2309 ap = &wpa->ia.ap;
2310 fuse_write_args_fill(&wpa->ia, data->ff, folio_pos(folio), 0);
2311 wpa->ia.write.in.write_flags |= FUSE_WRITE_CACHE;
2312 wpa->next = NULL;
2313 ap->args.in_pages = true;
2314 ap->args.end = fuse_writepage_end;
2315 ap->num_pages = 0;
2316 wpa->inode = inode;
2317 }
2318 folio_start_writeback(folio);
2319
2320 copy_highpage(tmp_page, &folio->page);
2321 ap->pages[ap->num_pages] = tmp_page;
2322 ap->descs[ap->num_pages].offset = 0;
2323 ap->descs[ap->num_pages].length = PAGE_SIZE;
2324 data->orig_pages[ap->num_pages] = &folio->page;
2325
2326 inc_wb_stat(&inode_to_bdi(inode)->wb, WB_WRITEBACK);
2327 inc_node_page_state(tmp_page, NR_WRITEBACK_TEMP);
2328
2329 err = 0;
2330 if (data->wpa) {
2331 /*
2332 * Protected by fi->lock against concurrent access by
2333 * fuse_page_is_writeback().
2334 */
2335 spin_lock(&fi->lock);
2336 ap->num_pages++;
2337 spin_unlock(&fi->lock);
2338 } else if (fuse_writepage_add(wpa, &folio->page)) {
2339 data->wpa = wpa;
2340 } else {
2341 folio_end_writeback(folio);
2342 }
2343out_unlock:
2344 folio_unlock(folio);
2345
2346 return err;
2347}
2348
2349static int fuse_writepages(struct address_space *mapping,
2350 struct writeback_control *wbc)
2351{
2352 struct inode *inode = mapping->host;
2353 struct fuse_conn *fc = get_fuse_conn(inode);
2354 struct fuse_fill_wb_data data;
2355 int err;
2356
2357 err = -EIO;
2358 if (fuse_is_bad(inode))
2359 goto out;
2360
2361 if (wbc->sync_mode == WB_SYNC_NONE &&
2362 fc->num_background >= fc->congestion_threshold)
2363 return 0;
2364
2365 data.inode = inode;
2366 data.wpa = NULL;
2367 data.ff = NULL;
2368
2369 err = -ENOMEM;
2370 data.orig_pages = kcalloc(fc->max_pages,
2371 sizeof(struct page *),
2372 GFP_NOFS);
2373 if (!data.orig_pages)
2374 goto out;
2375
2376 err = write_cache_pages(mapping, wbc, fuse_writepages_fill, &data);
2377 if (data.wpa) {
2378 WARN_ON(!data.wpa->ia.ap.num_pages);
2379 fuse_writepages_send(&data);
2380 }
2381 if (data.ff)
2382 fuse_file_put(data.ff, false);
2383
2384 kfree(data.orig_pages);
2385out:
2386 return err;
2387}
2388
2389/*
2390 * It's worthy to make sure that space is reserved on disk for the write,
2391 * but how to implement it without killing performance need more thinking.
2392 */
2393static int fuse_write_begin(struct file *file, struct address_space *mapping,
2394 loff_t pos, unsigned len, struct page **pagep, void **fsdata)
2395{
2396 pgoff_t index = pos >> PAGE_SHIFT;
2397 struct fuse_conn *fc = get_fuse_conn(file_inode(file));
2398 struct page *page;
2399 loff_t fsize;
2400 int err = -ENOMEM;
2401
2402 WARN_ON(!fc->writeback_cache);
2403
2404 page = grab_cache_page_write_begin(mapping, index);
2405 if (!page)
2406 goto error;
2407
2408 fuse_wait_on_page_writeback(mapping->host, page->index);
2409
2410 if (PageUptodate(page) || len == PAGE_SIZE)
2411 goto success;
2412 /*
2413 * Check if the start this page comes after the end of file, in which
2414 * case the readpage can be optimized away.
2415 */
2416 fsize = i_size_read(mapping->host);
2417 if (fsize <= (pos & PAGE_MASK)) {
2418 size_t off = pos & ~PAGE_MASK;
2419 if (off)
2420 zero_user_segment(page, 0, off);
2421 goto success;
2422 }
2423 err = fuse_do_readpage(file, page);
2424 if (err)
2425 goto cleanup;
2426success:
2427 *pagep = page;
2428 return 0;
2429
2430cleanup:
2431 unlock_page(page);
2432 put_page(page);
2433error:
2434 return err;
2435}
2436
2437static int fuse_write_end(struct file *file, struct address_space *mapping,
2438 loff_t pos, unsigned len, unsigned copied,
2439 struct page *page, void *fsdata)
2440{
2441 struct inode *inode = page->mapping->host;
2442
2443 /* Haven't copied anything? Skip zeroing, size extending, dirtying. */
2444 if (!copied)
2445 goto unlock;
2446
2447 pos += copied;
2448 if (!PageUptodate(page)) {
2449 /* Zero any unwritten bytes at the end of the page */
2450 size_t endoff = pos & ~PAGE_MASK;
2451 if (endoff)
2452 zero_user_segment(page, endoff, PAGE_SIZE);
2453 SetPageUptodate(page);
2454 }
2455
2456 if (pos > inode->i_size)
2457 i_size_write(inode, pos);
2458
2459 set_page_dirty(page);
2460
2461unlock:
2462 unlock_page(page);
2463 put_page(page);
2464
2465 return copied;
2466}
2467
2468static int fuse_launder_folio(struct folio *folio)
2469{
2470 int err = 0;
2471 if (folio_clear_dirty_for_io(folio)) {
2472 struct inode *inode = folio->mapping->host;
2473
2474 /* Serialize with pending writeback for the same page */
2475 fuse_wait_on_page_writeback(inode, folio->index);
2476 err = fuse_writepage_locked(folio);
2477 if (!err)
2478 fuse_wait_on_page_writeback(inode, folio->index);
2479 }
2480 return err;
2481}
2482
2483/*
2484 * Write back dirty data/metadata now (there may not be any suitable
2485 * open files later for data)
2486 */
2487static void fuse_vma_close(struct vm_area_struct *vma)
2488{
2489 int err;
2490
2491 err = write_inode_now(vma->vm_file->f_mapping->host, 1);
2492 mapping_set_error(vma->vm_file->f_mapping, err);
2493}
2494
2495/*
2496 * Wait for writeback against this page to complete before allowing it
2497 * to be marked dirty again, and hence written back again, possibly
2498 * before the previous writepage completed.
2499 *
2500 * Block here, instead of in ->writepage(), so that the userspace fs
2501 * can only block processes actually operating on the filesystem.
2502 *
2503 * Otherwise unprivileged userspace fs would be able to block
2504 * unrelated:
2505 *
2506 * - page migration
2507 * - sync(2)
2508 * - try_to_free_pages() with order > PAGE_ALLOC_COSTLY_ORDER
2509 */
2510static vm_fault_t fuse_page_mkwrite(struct vm_fault *vmf)
2511{
2512 struct page *page = vmf->page;
2513 struct inode *inode = file_inode(vmf->vma->vm_file);
2514
2515 file_update_time(vmf->vma->vm_file);
2516 lock_page(page);
2517 if (page->mapping != inode->i_mapping) {
2518 unlock_page(page);
2519 return VM_FAULT_NOPAGE;
2520 }
2521
2522 fuse_wait_on_page_writeback(inode, page->index);
2523 return VM_FAULT_LOCKED;
2524}
2525
2526static const struct vm_operations_struct fuse_file_vm_ops = {
2527 .close = fuse_vma_close,
2528 .fault = filemap_fault,
2529 .map_pages = filemap_map_pages,
2530 .page_mkwrite = fuse_page_mkwrite,
2531};
2532
2533static int fuse_file_mmap(struct file *file, struct vm_area_struct *vma)
2534{
2535 struct fuse_file *ff = file->private_data;
2536 struct fuse_conn *fc = ff->fm->fc;
2537 struct inode *inode = file_inode(file);
2538 int rc;
2539
2540 /* DAX mmap is superior to direct_io mmap */
2541 if (FUSE_IS_DAX(inode))
2542 return fuse_dax_mmap(file, vma);
2543
2544 /*
2545 * If inode is in passthrough io mode, because it has some file open
2546 * in passthrough mode, either mmap to backing file or fail mmap,
2547 * because mixing cached mmap and passthrough io mode is not allowed.
2548 */
2549 if (fuse_file_passthrough(ff))
2550 return fuse_passthrough_mmap(file, vma);
2551 else if (fuse_inode_backing(get_fuse_inode(inode)))
2552 return -ENODEV;
2553
2554 /*
2555 * FOPEN_DIRECT_IO handling is special compared to O_DIRECT,
2556 * as does not allow MAP_SHARED mmap without FUSE_DIRECT_IO_ALLOW_MMAP.
2557 */
2558 if (ff->open_flags & FOPEN_DIRECT_IO) {
2559 /*
2560 * Can't provide the coherency needed for MAP_SHARED
2561 * if FUSE_DIRECT_IO_ALLOW_MMAP isn't set.
2562 */
2563 if ((vma->vm_flags & VM_MAYSHARE) && !fc->direct_io_allow_mmap)
2564 return -ENODEV;
2565
2566 invalidate_inode_pages2(file->f_mapping);
2567
2568 if (!(vma->vm_flags & VM_MAYSHARE)) {
2569 /* MAP_PRIVATE */
2570 return generic_file_mmap(file, vma);
2571 }
2572
2573 /*
2574 * First mmap of direct_io file enters caching inode io mode.
2575 * Also waits for parallel dio writers to go into serial mode
2576 * (exclusive instead of shared lock).
2577 * After first mmap, the inode stays in caching io mode until
2578 * the direct_io file release.
2579 */
2580 rc = fuse_file_cached_io_open(inode, ff);
2581 if (rc)
2582 return rc;
2583 }
2584
2585 if ((vma->vm_flags & VM_SHARED) && (vma->vm_flags & VM_MAYWRITE))
2586 fuse_link_write_file(file);
2587
2588 file_accessed(file);
2589 vma->vm_ops = &fuse_file_vm_ops;
2590 return 0;
2591}
2592
2593static int convert_fuse_file_lock(struct fuse_conn *fc,
2594 const struct fuse_file_lock *ffl,
2595 struct file_lock *fl)
2596{
2597 switch (ffl->type) {
2598 case F_UNLCK:
2599 break;
2600
2601 case F_RDLCK:
2602 case F_WRLCK:
2603 if (ffl->start > OFFSET_MAX || ffl->end > OFFSET_MAX ||
2604 ffl->end < ffl->start)
2605 return -EIO;
2606
2607 fl->fl_start = ffl->start;
2608 fl->fl_end = ffl->end;
2609
2610 /*
2611 * Convert pid into init's pid namespace. The locks API will
2612 * translate it into the caller's pid namespace.
2613 */
2614 rcu_read_lock();
2615 fl->c.flc_pid = pid_nr_ns(find_pid_ns(ffl->pid, fc->pid_ns), &init_pid_ns);
2616 rcu_read_unlock();
2617 break;
2618
2619 default:
2620 return -EIO;
2621 }
2622 fl->c.flc_type = ffl->type;
2623 return 0;
2624}
2625
2626static void fuse_lk_fill(struct fuse_args *args, struct file *file,
2627 const struct file_lock *fl, int opcode, pid_t pid,
2628 int flock, struct fuse_lk_in *inarg)
2629{
2630 struct inode *inode = file_inode(file);
2631 struct fuse_conn *fc = get_fuse_conn(inode);
2632 struct fuse_file *ff = file->private_data;
2633
2634 memset(inarg, 0, sizeof(*inarg));
2635 inarg->fh = ff->fh;
2636 inarg->owner = fuse_lock_owner_id(fc, fl->c.flc_owner);
2637 inarg->lk.start = fl->fl_start;
2638 inarg->lk.end = fl->fl_end;
2639 inarg->lk.type = fl->c.flc_type;
2640 inarg->lk.pid = pid;
2641 if (flock)
2642 inarg->lk_flags |= FUSE_LK_FLOCK;
2643 args->opcode = opcode;
2644 args->nodeid = get_node_id(inode);
2645 args->in_numargs = 1;
2646 args->in_args[0].size = sizeof(*inarg);
2647 args->in_args[0].value = inarg;
2648}
2649
2650static int fuse_getlk(struct file *file, struct file_lock *fl)
2651{
2652 struct inode *inode = file_inode(file);
2653 struct fuse_mount *fm = get_fuse_mount(inode);
2654 FUSE_ARGS(args);
2655 struct fuse_lk_in inarg;
2656 struct fuse_lk_out outarg;
2657 int err;
2658
2659 fuse_lk_fill(&args, file, fl, FUSE_GETLK, 0, 0, &inarg);
2660 args.out_numargs = 1;
2661 args.out_args[0].size = sizeof(outarg);
2662 args.out_args[0].value = &outarg;
2663 err = fuse_simple_request(fm, &args);
2664 if (!err)
2665 err = convert_fuse_file_lock(fm->fc, &outarg.lk, fl);
2666
2667 return err;
2668}
2669
2670static int fuse_setlk(struct file *file, struct file_lock *fl, int flock)
2671{
2672 struct inode *inode = file_inode(file);
2673 struct fuse_mount *fm = get_fuse_mount(inode);
2674 FUSE_ARGS(args);
2675 struct fuse_lk_in inarg;
2676 int opcode = (fl->c.flc_flags & FL_SLEEP) ? FUSE_SETLKW : FUSE_SETLK;
2677 struct pid *pid = fl->c.flc_type != F_UNLCK ? task_tgid(current) : NULL;
2678 pid_t pid_nr = pid_nr_ns(pid, fm->fc->pid_ns);
2679 int err;
2680
2681 if (fl->fl_lmops && fl->fl_lmops->lm_grant) {
2682 /* NLM needs asynchronous locks, which we don't support yet */
2683 return -ENOLCK;
2684 }
2685
2686 fuse_lk_fill(&args, file, fl, opcode, pid_nr, flock, &inarg);
2687 err = fuse_simple_request(fm, &args);
2688
2689 /* locking is restartable */
2690 if (err == -EINTR)
2691 err = -ERESTARTSYS;
2692
2693 return err;
2694}
2695
2696static int fuse_file_lock(struct file *file, int cmd, struct file_lock *fl)
2697{
2698 struct inode *inode = file_inode(file);
2699 struct fuse_conn *fc = get_fuse_conn(inode);
2700 int err;
2701
2702 if (cmd == F_CANCELLK) {
2703 err = 0;
2704 } else if (cmd == F_GETLK) {
2705 if (fc->no_lock) {
2706 posix_test_lock(file, fl);
2707 err = 0;
2708 } else
2709 err = fuse_getlk(file, fl);
2710 } else {
2711 if (fc->no_lock)
2712 err = posix_lock_file(file, fl, NULL);
2713 else
2714 err = fuse_setlk(file, fl, 0);
2715 }
2716 return err;
2717}
2718
2719static int fuse_file_flock(struct file *file, int cmd, struct file_lock *fl)
2720{
2721 struct inode *inode = file_inode(file);
2722 struct fuse_conn *fc = get_fuse_conn(inode);
2723 int err;
2724
2725 if (fc->no_flock) {
2726 err = locks_lock_file_wait(file, fl);
2727 } else {
2728 struct fuse_file *ff = file->private_data;
2729
2730 /* emulate flock with POSIX locks */
2731 ff->flock = true;
2732 err = fuse_setlk(file, fl, 1);
2733 }
2734
2735 return err;
2736}
2737
2738static sector_t fuse_bmap(struct address_space *mapping, sector_t block)
2739{
2740 struct inode *inode = mapping->host;
2741 struct fuse_mount *fm = get_fuse_mount(inode);
2742 FUSE_ARGS(args);
2743 struct fuse_bmap_in inarg;
2744 struct fuse_bmap_out outarg;
2745 int err;
2746
2747 if (!inode->i_sb->s_bdev || fm->fc->no_bmap)
2748 return 0;
2749
2750 memset(&inarg, 0, sizeof(inarg));
2751 inarg.block = block;
2752 inarg.blocksize = inode->i_sb->s_blocksize;
2753 args.opcode = FUSE_BMAP;
2754 args.nodeid = get_node_id(inode);
2755 args.in_numargs = 1;
2756 args.in_args[0].size = sizeof(inarg);
2757 args.in_args[0].value = &inarg;
2758 args.out_numargs = 1;
2759 args.out_args[0].size = sizeof(outarg);
2760 args.out_args[0].value = &outarg;
2761 err = fuse_simple_request(fm, &args);
2762 if (err == -ENOSYS)
2763 fm->fc->no_bmap = 1;
2764
2765 return err ? 0 : outarg.block;
2766}
2767
2768static loff_t fuse_lseek(struct file *file, loff_t offset, int whence)
2769{
2770 struct inode *inode = file->f_mapping->host;
2771 struct fuse_mount *fm = get_fuse_mount(inode);
2772 struct fuse_file *ff = file->private_data;
2773 FUSE_ARGS(args);
2774 struct fuse_lseek_in inarg = {
2775 .fh = ff->fh,
2776 .offset = offset,
2777 .whence = whence
2778 };
2779 struct fuse_lseek_out outarg;
2780 int err;
2781
2782 if (fm->fc->no_lseek)
2783 goto fallback;
2784
2785 args.opcode = FUSE_LSEEK;
2786 args.nodeid = ff->nodeid;
2787 args.in_numargs = 1;
2788 args.in_args[0].size = sizeof(inarg);
2789 args.in_args[0].value = &inarg;
2790 args.out_numargs = 1;
2791 args.out_args[0].size = sizeof(outarg);
2792 args.out_args[0].value = &outarg;
2793 err = fuse_simple_request(fm, &args);
2794 if (err) {
2795 if (err == -ENOSYS) {
2796 fm->fc->no_lseek = 1;
2797 goto fallback;
2798 }
2799 return err;
2800 }
2801
2802 return vfs_setpos(file, outarg.offset, inode->i_sb->s_maxbytes);
2803
2804fallback:
2805 err = fuse_update_attributes(inode, file, STATX_SIZE);
2806 if (!err)
2807 return generic_file_llseek(file, offset, whence);
2808 else
2809 return err;
2810}
2811
2812static loff_t fuse_file_llseek(struct file *file, loff_t offset, int whence)
2813{
2814 loff_t retval;
2815 struct inode *inode = file_inode(file);
2816
2817 switch (whence) {
2818 case SEEK_SET:
2819 case SEEK_CUR:
2820 /* No i_mutex protection necessary for SEEK_CUR and SEEK_SET */
2821 retval = generic_file_llseek(file, offset, whence);
2822 break;
2823 case SEEK_END:
2824 inode_lock(inode);
2825 retval = fuse_update_attributes(inode, file, STATX_SIZE);
2826 if (!retval)
2827 retval = generic_file_llseek(file, offset, whence);
2828 inode_unlock(inode);
2829 break;
2830 case SEEK_HOLE:
2831 case SEEK_DATA:
2832 inode_lock(inode);
2833 retval = fuse_lseek(file, offset, whence);
2834 inode_unlock(inode);
2835 break;
2836 default:
2837 retval = -EINVAL;
2838 }
2839
2840 return retval;
2841}
2842
2843/*
2844 * All files which have been polled are linked to RB tree
2845 * fuse_conn->polled_files which is indexed by kh. Walk the tree and
2846 * find the matching one.
2847 */
2848static struct rb_node **fuse_find_polled_node(struct fuse_conn *fc, u64 kh,
2849 struct rb_node **parent_out)
2850{
2851 struct rb_node **link = &fc->polled_files.rb_node;
2852 struct rb_node *last = NULL;
2853
2854 while (*link) {
2855 struct fuse_file *ff;
2856
2857 last = *link;
2858 ff = rb_entry(last, struct fuse_file, polled_node);
2859
2860 if (kh < ff->kh)
2861 link = &last->rb_left;
2862 else if (kh > ff->kh)
2863 link = &last->rb_right;
2864 else
2865 return link;
2866 }
2867
2868 if (parent_out)
2869 *parent_out = last;
2870 return link;
2871}
2872
2873/*
2874 * The file is about to be polled. Make sure it's on the polled_files
2875 * RB tree. Note that files once added to the polled_files tree are
2876 * not removed before the file is released. This is because a file
2877 * polled once is likely to be polled again.
2878 */
2879static void fuse_register_polled_file(struct fuse_conn *fc,
2880 struct fuse_file *ff)
2881{
2882 spin_lock(&fc->lock);
2883 if (RB_EMPTY_NODE(&ff->polled_node)) {
2884 struct rb_node **link, *parent;
2885
2886 link = fuse_find_polled_node(fc, ff->kh, &parent);
2887 BUG_ON(*link);
2888 rb_link_node(&ff->polled_node, parent, link);
2889 rb_insert_color(&ff->polled_node, &fc->polled_files);
2890 }
2891 spin_unlock(&fc->lock);
2892}
2893
2894__poll_t fuse_file_poll(struct file *file, poll_table *wait)
2895{
2896 struct fuse_file *ff = file->private_data;
2897 struct fuse_mount *fm = ff->fm;
2898 struct fuse_poll_in inarg = { .fh = ff->fh, .kh = ff->kh };
2899 struct fuse_poll_out outarg;
2900 FUSE_ARGS(args);
2901 int err;
2902
2903 if (fm->fc->no_poll)
2904 return DEFAULT_POLLMASK;
2905
2906 poll_wait(file, &ff->poll_wait, wait);
2907 inarg.events = mangle_poll(poll_requested_events(wait));
2908
2909 /*
2910 * Ask for notification iff there's someone waiting for it.
2911 * The client may ignore the flag and always notify.
2912 */
2913 if (waitqueue_active(&ff->poll_wait)) {
2914 inarg.flags |= FUSE_POLL_SCHEDULE_NOTIFY;
2915 fuse_register_polled_file(fm->fc, ff);
2916 }
2917
2918 args.opcode = FUSE_POLL;
2919 args.nodeid = ff->nodeid;
2920 args.in_numargs = 1;
2921 args.in_args[0].size = sizeof(inarg);
2922 args.in_args[0].value = &inarg;
2923 args.out_numargs = 1;
2924 args.out_args[0].size = sizeof(outarg);
2925 args.out_args[0].value = &outarg;
2926 err = fuse_simple_request(fm, &args);
2927
2928 if (!err)
2929 return demangle_poll(outarg.revents);
2930 if (err == -ENOSYS) {
2931 fm->fc->no_poll = 1;
2932 return DEFAULT_POLLMASK;
2933 }
2934 return EPOLLERR;
2935}
2936EXPORT_SYMBOL_GPL(fuse_file_poll);
2937
2938/*
2939 * This is called from fuse_handle_notify() on FUSE_NOTIFY_POLL and
2940 * wakes up the poll waiters.
2941 */
2942int fuse_notify_poll_wakeup(struct fuse_conn *fc,
2943 struct fuse_notify_poll_wakeup_out *outarg)
2944{
2945 u64 kh = outarg->kh;
2946 struct rb_node **link;
2947
2948 spin_lock(&fc->lock);
2949
2950 link = fuse_find_polled_node(fc, kh, NULL);
2951 if (*link) {
2952 struct fuse_file *ff;
2953
2954 ff = rb_entry(*link, struct fuse_file, polled_node);
2955 wake_up_interruptible_sync(&ff->poll_wait);
2956 }
2957
2958 spin_unlock(&fc->lock);
2959 return 0;
2960}
2961
2962static void fuse_do_truncate(struct file *file)
2963{
2964 struct inode *inode = file->f_mapping->host;
2965 struct iattr attr;
2966
2967 attr.ia_valid = ATTR_SIZE;
2968 attr.ia_size = i_size_read(inode);
2969
2970 attr.ia_file = file;
2971 attr.ia_valid |= ATTR_FILE;
2972
2973 fuse_do_setattr(file_dentry(file), &attr, file);
2974}
2975
2976static inline loff_t fuse_round_up(struct fuse_conn *fc, loff_t off)
2977{
2978 return round_up(off, fc->max_pages << PAGE_SHIFT);
2979}
2980
2981static ssize_t
2982fuse_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
2983{
2984 DECLARE_COMPLETION_ONSTACK(wait);
2985 ssize_t ret = 0;
2986 struct file *file = iocb->ki_filp;
2987 struct fuse_file *ff = file->private_data;
2988 loff_t pos = 0;
2989 struct inode *inode;
2990 loff_t i_size;
2991 size_t count = iov_iter_count(iter), shortened = 0;
2992 loff_t offset = iocb->ki_pos;
2993 struct fuse_io_priv *io;
2994
2995 pos = offset;
2996 inode = file->f_mapping->host;
2997 i_size = i_size_read(inode);
2998
2999 if ((iov_iter_rw(iter) == READ) && (offset >= i_size))
3000 return 0;
3001
3002 io = kmalloc(sizeof(struct fuse_io_priv), GFP_KERNEL);
3003 if (!io)
3004 return -ENOMEM;
3005 spin_lock_init(&io->lock);
3006 kref_init(&io->refcnt);
3007 io->reqs = 1;
3008 io->bytes = -1;
3009 io->size = 0;
3010 io->offset = offset;
3011 io->write = (iov_iter_rw(iter) == WRITE);
3012 io->err = 0;
3013 /*
3014 * By default, we want to optimize all I/Os with async request
3015 * submission to the client filesystem if supported.
3016 */
3017 io->async = ff->fm->fc->async_dio;
3018 io->iocb = iocb;
3019 io->blocking = is_sync_kiocb(iocb);
3020
3021 /* optimization for short read */
3022 if (io->async && !io->write && offset + count > i_size) {
3023 iov_iter_truncate(iter, fuse_round_up(ff->fm->fc, i_size - offset));
3024 shortened = count - iov_iter_count(iter);
3025 count -= shortened;
3026 }
3027
3028 /*
3029 * We cannot asynchronously extend the size of a file.
3030 * In such case the aio will behave exactly like sync io.
3031 */
3032 if ((offset + count > i_size) && io->write)
3033 io->blocking = true;
3034
3035 if (io->async && io->blocking) {
3036 /*
3037 * Additional reference to keep io around after
3038 * calling fuse_aio_complete()
3039 */
3040 kref_get(&io->refcnt);
3041 io->done = &wait;
3042 }
3043
3044 if (iov_iter_rw(iter) == WRITE) {
3045 ret = fuse_direct_io(io, iter, &pos, FUSE_DIO_WRITE);
3046 fuse_invalidate_attr_mask(inode, FUSE_STATX_MODSIZE);
3047 } else {
3048 ret = __fuse_direct_read(io, iter, &pos);
3049 }
3050 iov_iter_reexpand(iter, iov_iter_count(iter) + shortened);
3051
3052 if (io->async) {
3053 bool blocking = io->blocking;
3054
3055 fuse_aio_complete(io, ret < 0 ? ret : 0, -1);
3056
3057 /* we have a non-extending, async request, so return */
3058 if (!blocking)
3059 return -EIOCBQUEUED;
3060
3061 wait_for_completion(&wait);
3062 ret = fuse_get_res_by_io(io);
3063 }
3064
3065 kref_put(&io->refcnt, fuse_io_release);
3066
3067 if (iov_iter_rw(iter) == WRITE) {
3068 fuse_write_update_attr(inode, pos, ret);
3069 /* For extending writes we already hold exclusive lock */
3070 if (ret < 0 && offset + count > i_size)
3071 fuse_do_truncate(file);
3072 }
3073
3074 return ret;
3075}
3076
3077static int fuse_writeback_range(struct inode *inode, loff_t start, loff_t end)
3078{
3079 int err = filemap_write_and_wait_range(inode->i_mapping, start, LLONG_MAX);
3080
3081 if (!err)
3082 fuse_sync_writes(inode);
3083
3084 return err;
3085}
3086
3087static long fuse_file_fallocate(struct file *file, int mode, loff_t offset,
3088 loff_t length)
3089{
3090 struct fuse_file *ff = file->private_data;
3091 struct inode *inode = file_inode(file);
3092 struct fuse_inode *fi = get_fuse_inode(inode);
3093 struct fuse_mount *fm = ff->fm;
3094 FUSE_ARGS(args);
3095 struct fuse_fallocate_in inarg = {
3096 .fh = ff->fh,
3097 .offset = offset,
3098 .length = length,
3099 .mode = mode
3100 };
3101 int err;
3102 bool block_faults = FUSE_IS_DAX(inode) &&
3103 (!(mode & FALLOC_FL_KEEP_SIZE) ||
3104 (mode & (FALLOC_FL_PUNCH_HOLE | FALLOC_FL_ZERO_RANGE)));
3105
3106 if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE |
3107 FALLOC_FL_ZERO_RANGE))
3108 return -EOPNOTSUPP;
3109
3110 if (fm->fc->no_fallocate)
3111 return -EOPNOTSUPP;
3112
3113 inode_lock(inode);
3114 if (block_faults) {
3115 filemap_invalidate_lock(inode->i_mapping);
3116 err = fuse_dax_break_layouts(inode, 0, 0);
3117 if (err)
3118 goto out;
3119 }
3120
3121 if (mode & (FALLOC_FL_PUNCH_HOLE | FALLOC_FL_ZERO_RANGE)) {
3122 loff_t endbyte = offset + length - 1;
3123
3124 err = fuse_writeback_range(inode, offset, endbyte);
3125 if (err)
3126 goto out;
3127 }
3128
3129 if (!(mode & FALLOC_FL_KEEP_SIZE) &&
3130 offset + length > i_size_read(inode)) {
3131 err = inode_newsize_ok(inode, offset + length);
3132 if (err)
3133 goto out;
3134 }
3135
3136 err = file_modified(file);
3137 if (err)
3138 goto out;
3139
3140 if (!(mode & FALLOC_FL_KEEP_SIZE))
3141 set_bit(FUSE_I_SIZE_UNSTABLE, &fi->state);
3142
3143 args.opcode = FUSE_FALLOCATE;
3144 args.nodeid = ff->nodeid;
3145 args.in_numargs = 1;
3146 args.in_args[0].size = sizeof(inarg);
3147 args.in_args[0].value = &inarg;
3148 err = fuse_simple_request(fm, &args);
3149 if (err == -ENOSYS) {
3150 fm->fc->no_fallocate = 1;
3151 err = -EOPNOTSUPP;
3152 }
3153 if (err)
3154 goto out;
3155
3156 /* we could have extended the file */
3157 if (!(mode & FALLOC_FL_KEEP_SIZE)) {
3158 if (fuse_write_update_attr(inode, offset + length, length))
3159 file_update_time(file);
3160 }
3161
3162 if (mode & (FALLOC_FL_PUNCH_HOLE | FALLOC_FL_ZERO_RANGE))
3163 truncate_pagecache_range(inode, offset, offset + length - 1);
3164
3165 fuse_invalidate_attr_mask(inode, FUSE_STATX_MODSIZE);
3166
3167out:
3168 if (!(mode & FALLOC_FL_KEEP_SIZE))
3169 clear_bit(FUSE_I_SIZE_UNSTABLE, &fi->state);
3170
3171 if (block_faults)
3172 filemap_invalidate_unlock(inode->i_mapping);
3173
3174 inode_unlock(inode);
3175
3176 fuse_flush_time_update(inode);
3177
3178 return err;
3179}
3180
3181static ssize_t __fuse_copy_file_range(struct file *file_in, loff_t pos_in,
3182 struct file *file_out, loff_t pos_out,
3183 size_t len, unsigned int flags)
3184{
3185 struct fuse_file *ff_in = file_in->private_data;
3186 struct fuse_file *ff_out = file_out->private_data;
3187 struct inode *inode_in = file_inode(file_in);
3188 struct inode *inode_out = file_inode(file_out);
3189 struct fuse_inode *fi_out = get_fuse_inode(inode_out);
3190 struct fuse_mount *fm = ff_in->fm;
3191 struct fuse_conn *fc = fm->fc;
3192 FUSE_ARGS(args);
3193 struct fuse_copy_file_range_in inarg = {
3194 .fh_in = ff_in->fh,
3195 .off_in = pos_in,
3196 .nodeid_out = ff_out->nodeid,
3197 .fh_out = ff_out->fh,
3198 .off_out = pos_out,
3199 .len = len,
3200 .flags = flags
3201 };
3202 struct fuse_write_out outarg;
3203 ssize_t err;
3204 /* mark unstable when write-back is not used, and file_out gets
3205 * extended */
3206 bool is_unstable = (!fc->writeback_cache) &&
3207 ((pos_out + len) > inode_out->i_size);
3208
3209 if (fc->no_copy_file_range)
3210 return -EOPNOTSUPP;
3211
3212 if (file_inode(file_in)->i_sb != file_inode(file_out)->i_sb)
3213 return -EXDEV;
3214
3215 inode_lock(inode_in);
3216 err = fuse_writeback_range(inode_in, pos_in, pos_in + len - 1);
3217 inode_unlock(inode_in);
3218 if (err)
3219 return err;
3220
3221 inode_lock(inode_out);
3222
3223 err = file_modified(file_out);
3224 if (err)
3225 goto out;
3226
3227 /*
3228 * Write out dirty pages in the destination file before sending the COPY
3229 * request to userspace. After the request is completed, truncate off
3230 * pages (including partial ones) from the cache that have been copied,
3231 * since these contain stale data at that point.
3232 *
3233 * This should be mostly correct, but if the COPY writes to partial
3234 * pages (at the start or end) and the parts not covered by the COPY are
3235 * written through a memory map after calling fuse_writeback_range(),
3236 * then these partial page modifications will be lost on truncation.
3237 *
3238 * It is unlikely that someone would rely on such mixed style
3239 * modifications. Yet this does give less guarantees than if the
3240 * copying was performed with write(2).
3241 *
3242 * To fix this a mapping->invalidate_lock could be used to prevent new
3243 * faults while the copy is ongoing.
3244 */
3245 err = fuse_writeback_range(inode_out, pos_out, pos_out + len - 1);
3246 if (err)
3247 goto out;
3248
3249 if (is_unstable)
3250 set_bit(FUSE_I_SIZE_UNSTABLE, &fi_out->state);
3251
3252 args.opcode = FUSE_COPY_FILE_RANGE;
3253 args.nodeid = ff_in->nodeid;
3254 args.in_numargs = 1;
3255 args.in_args[0].size = sizeof(inarg);
3256 args.in_args[0].value = &inarg;
3257 args.out_numargs = 1;
3258 args.out_args[0].size = sizeof(outarg);
3259 args.out_args[0].value = &outarg;
3260 err = fuse_simple_request(fm, &args);
3261 if (err == -ENOSYS) {
3262 fc->no_copy_file_range = 1;
3263 err = -EOPNOTSUPP;
3264 }
3265 if (err)
3266 goto out;
3267
3268 truncate_inode_pages_range(inode_out->i_mapping,
3269 ALIGN_DOWN(pos_out, PAGE_SIZE),
3270 ALIGN(pos_out + outarg.size, PAGE_SIZE) - 1);
3271
3272 file_update_time(file_out);
3273 fuse_write_update_attr(inode_out, pos_out + outarg.size, outarg.size);
3274
3275 err = outarg.size;
3276out:
3277 if (is_unstable)
3278 clear_bit(FUSE_I_SIZE_UNSTABLE, &fi_out->state);
3279
3280 inode_unlock(inode_out);
3281 file_accessed(file_in);
3282
3283 fuse_flush_time_update(inode_out);
3284
3285 return err;
3286}
3287
3288static ssize_t fuse_copy_file_range(struct file *src_file, loff_t src_off,
3289 struct file *dst_file, loff_t dst_off,
3290 size_t len, unsigned int flags)
3291{
3292 ssize_t ret;
3293
3294 ret = __fuse_copy_file_range(src_file, src_off, dst_file, dst_off,
3295 len, flags);
3296
3297 if (ret == -EOPNOTSUPP || ret == -EXDEV)
3298 ret = splice_copy_file_range(src_file, src_off, dst_file,
3299 dst_off, len);
3300 return ret;
3301}
3302
3303static const struct file_operations fuse_file_operations = {
3304 .llseek = fuse_file_llseek,
3305 .read_iter = fuse_file_read_iter,
3306 .write_iter = fuse_file_write_iter,
3307 .mmap = fuse_file_mmap,
3308 .open = fuse_open,
3309 .flush = fuse_flush,
3310 .release = fuse_release,
3311 .fsync = fuse_fsync,
3312 .lock = fuse_file_lock,
3313 .get_unmapped_area = thp_get_unmapped_area,
3314 .flock = fuse_file_flock,
3315 .splice_read = fuse_splice_read,
3316 .splice_write = fuse_splice_write,
3317 .unlocked_ioctl = fuse_file_ioctl,
3318 .compat_ioctl = fuse_file_compat_ioctl,
3319 .poll = fuse_file_poll,
3320 .fallocate = fuse_file_fallocate,
3321 .copy_file_range = fuse_copy_file_range,
3322};
3323
3324static const struct address_space_operations fuse_file_aops = {
3325 .read_folio = fuse_read_folio,
3326 .readahead = fuse_readahead,
3327 .writepages = fuse_writepages,
3328 .launder_folio = fuse_launder_folio,
3329 .dirty_folio = filemap_dirty_folio,
3330 .migrate_folio = filemap_migrate_folio,
3331 .bmap = fuse_bmap,
3332 .direct_IO = fuse_direct_IO,
3333 .write_begin = fuse_write_begin,
3334 .write_end = fuse_write_end,
3335};
3336
3337void fuse_init_file_inode(struct inode *inode, unsigned int flags)
3338{
3339 struct fuse_inode *fi = get_fuse_inode(inode);
3340
3341 inode->i_fop = &fuse_file_operations;
3342 inode->i_data.a_ops = &fuse_file_aops;
3343
3344 INIT_LIST_HEAD(&fi->write_files);
3345 INIT_LIST_HEAD(&fi->queued_writes);
3346 fi->writectr = 0;
3347 fi->iocachectr = 0;
3348 init_waitqueue_head(&fi->page_waitq);
3349 init_waitqueue_head(&fi->direct_io_waitq);
3350 fi->writepages = RB_ROOT;
3351
3352 if (IS_ENABLED(CONFIG_FUSE_DAX))
3353 fuse_dax_inode_init(inode, flags);
3354}
1/*
2 FUSE: Filesystem in Userspace
3 Copyright (C) 2001-2008 Miklos Szeredi <miklos@szeredi.hu>
4
5 This program can be distributed under the terms of the GNU GPL.
6 See the file COPYING.
7*/
8
9#include "fuse_i.h"
10
11#include <linux/pagemap.h>
12#include <linux/slab.h>
13#include <linux/kernel.h>
14#include <linux/sched.h>
15#include <linux/module.h>
16#include <linux/compat.h>
17#include <linux/swap.h>
18#include <linux/aio.h>
19#include <linux/falloc.h>
20
21static const struct file_operations fuse_direct_io_file_operations;
22
23static int fuse_send_open(struct fuse_conn *fc, u64 nodeid, struct file *file,
24 int opcode, struct fuse_open_out *outargp)
25{
26 struct fuse_open_in inarg;
27 struct fuse_req *req;
28 int err;
29
30 req = fuse_get_req_nopages(fc);
31 if (IS_ERR(req))
32 return PTR_ERR(req);
33
34 memset(&inarg, 0, sizeof(inarg));
35 inarg.flags = file->f_flags & ~(O_CREAT | O_EXCL | O_NOCTTY);
36 if (!fc->atomic_o_trunc)
37 inarg.flags &= ~O_TRUNC;
38 req->in.h.opcode = opcode;
39 req->in.h.nodeid = nodeid;
40 req->in.numargs = 1;
41 req->in.args[0].size = sizeof(inarg);
42 req->in.args[0].value = &inarg;
43 req->out.numargs = 1;
44 req->out.args[0].size = sizeof(*outargp);
45 req->out.args[0].value = outargp;
46 fuse_request_send(fc, req);
47 err = req->out.h.error;
48 fuse_put_request(fc, req);
49
50 return err;
51}
52
53struct fuse_file *fuse_file_alloc(struct fuse_conn *fc)
54{
55 struct fuse_file *ff;
56
57 ff = kmalloc(sizeof(struct fuse_file), GFP_KERNEL);
58 if (unlikely(!ff))
59 return NULL;
60
61 ff->fc = fc;
62 ff->reserved_req = fuse_request_alloc(0);
63 if (unlikely(!ff->reserved_req)) {
64 kfree(ff);
65 return NULL;
66 }
67
68 INIT_LIST_HEAD(&ff->write_entry);
69 atomic_set(&ff->count, 0);
70 RB_CLEAR_NODE(&ff->polled_node);
71 init_waitqueue_head(&ff->poll_wait);
72
73 spin_lock(&fc->lock);
74 ff->kh = ++fc->khctr;
75 spin_unlock(&fc->lock);
76
77 return ff;
78}
79
80void fuse_file_free(struct fuse_file *ff)
81{
82 fuse_request_free(ff->reserved_req);
83 kfree(ff);
84}
85
86struct fuse_file *fuse_file_get(struct fuse_file *ff)
87{
88 atomic_inc(&ff->count);
89 return ff;
90}
91
92static void fuse_release_async(struct work_struct *work)
93{
94 struct fuse_req *req;
95 struct fuse_conn *fc;
96 struct path path;
97
98 req = container_of(work, struct fuse_req, misc.release.work);
99 path = req->misc.release.path;
100 fc = get_fuse_conn(path.dentry->d_inode);
101
102 fuse_put_request(fc, req);
103 path_put(&path);
104}
105
106static void fuse_release_end(struct fuse_conn *fc, struct fuse_req *req)
107{
108 if (fc->destroy_req) {
109 /*
110 * If this is a fuseblk mount, then it's possible that
111 * releasing the path will result in releasing the
112 * super block and sending the DESTROY request. If
113 * the server is single threaded, this would hang.
114 * For this reason do the path_put() in a separate
115 * thread.
116 */
117 atomic_inc(&req->count);
118 INIT_WORK(&req->misc.release.work, fuse_release_async);
119 schedule_work(&req->misc.release.work);
120 } else {
121 path_put(&req->misc.release.path);
122 }
123}
124
125static void fuse_file_put(struct fuse_file *ff, bool sync)
126{
127 if (atomic_dec_and_test(&ff->count)) {
128 struct fuse_req *req = ff->reserved_req;
129
130 if (ff->fc->no_open) {
131 /*
132 * Drop the release request when client does not
133 * implement 'open'
134 */
135 req->background = 0;
136 path_put(&req->misc.release.path);
137 fuse_put_request(ff->fc, req);
138 } else if (sync) {
139 req->background = 0;
140 fuse_request_send(ff->fc, req);
141 path_put(&req->misc.release.path);
142 fuse_put_request(ff->fc, req);
143 } else {
144 req->end = fuse_release_end;
145 req->background = 1;
146 fuse_request_send_background(ff->fc, req);
147 }
148 kfree(ff);
149 }
150}
151
152int fuse_do_open(struct fuse_conn *fc, u64 nodeid, struct file *file,
153 bool isdir)
154{
155 struct fuse_file *ff;
156 int opcode = isdir ? FUSE_OPENDIR : FUSE_OPEN;
157
158 ff = fuse_file_alloc(fc);
159 if (!ff)
160 return -ENOMEM;
161
162 ff->fh = 0;
163 ff->open_flags = FOPEN_KEEP_CACHE; /* Default for no-open */
164 if (!fc->no_open || isdir) {
165 struct fuse_open_out outarg;
166 int err;
167
168 err = fuse_send_open(fc, nodeid, file, opcode, &outarg);
169 if (!err) {
170 ff->fh = outarg.fh;
171 ff->open_flags = outarg.open_flags;
172
173 } else if (err != -ENOSYS || isdir) {
174 fuse_file_free(ff);
175 return err;
176 } else {
177 fc->no_open = 1;
178 }
179 }
180
181 if (isdir)
182 ff->open_flags &= ~FOPEN_DIRECT_IO;
183
184 ff->nodeid = nodeid;
185 file->private_data = fuse_file_get(ff);
186
187 return 0;
188}
189EXPORT_SYMBOL_GPL(fuse_do_open);
190
191static void fuse_link_write_file(struct file *file)
192{
193 struct inode *inode = file_inode(file);
194 struct fuse_conn *fc = get_fuse_conn(inode);
195 struct fuse_inode *fi = get_fuse_inode(inode);
196 struct fuse_file *ff = file->private_data;
197 /*
198 * file may be written through mmap, so chain it onto the
199 * inodes's write_file list
200 */
201 spin_lock(&fc->lock);
202 if (list_empty(&ff->write_entry))
203 list_add(&ff->write_entry, &fi->write_files);
204 spin_unlock(&fc->lock);
205}
206
207void fuse_finish_open(struct inode *inode, struct file *file)
208{
209 struct fuse_file *ff = file->private_data;
210 struct fuse_conn *fc = get_fuse_conn(inode);
211
212 if (ff->open_flags & FOPEN_DIRECT_IO)
213 file->f_op = &fuse_direct_io_file_operations;
214 if (!(ff->open_flags & FOPEN_KEEP_CACHE))
215 invalidate_inode_pages2(inode->i_mapping);
216 if (ff->open_flags & FOPEN_NONSEEKABLE)
217 nonseekable_open(inode, file);
218 if (fc->atomic_o_trunc && (file->f_flags & O_TRUNC)) {
219 struct fuse_inode *fi = get_fuse_inode(inode);
220
221 spin_lock(&fc->lock);
222 fi->attr_version = ++fc->attr_version;
223 i_size_write(inode, 0);
224 spin_unlock(&fc->lock);
225 fuse_invalidate_attr(inode);
226 if (fc->writeback_cache)
227 file_update_time(file);
228 }
229 if ((file->f_mode & FMODE_WRITE) && fc->writeback_cache)
230 fuse_link_write_file(file);
231}
232
233int fuse_open_common(struct inode *inode, struct file *file, bool isdir)
234{
235 struct fuse_conn *fc = get_fuse_conn(inode);
236 int err;
237 bool lock_inode = (file->f_flags & O_TRUNC) &&
238 fc->atomic_o_trunc &&
239 fc->writeback_cache;
240
241 err = generic_file_open(inode, file);
242 if (err)
243 return err;
244
245 if (lock_inode)
246 mutex_lock(&inode->i_mutex);
247
248 err = fuse_do_open(fc, get_node_id(inode), file, isdir);
249
250 if (!err)
251 fuse_finish_open(inode, file);
252
253 if (lock_inode)
254 mutex_unlock(&inode->i_mutex);
255
256 return err;
257}
258
259static void fuse_prepare_release(struct fuse_file *ff, int flags, int opcode)
260{
261 struct fuse_conn *fc = ff->fc;
262 struct fuse_req *req = ff->reserved_req;
263 struct fuse_release_in *inarg = &req->misc.release.in;
264
265 spin_lock(&fc->lock);
266 list_del(&ff->write_entry);
267 if (!RB_EMPTY_NODE(&ff->polled_node))
268 rb_erase(&ff->polled_node, &fc->polled_files);
269 spin_unlock(&fc->lock);
270
271 wake_up_interruptible_all(&ff->poll_wait);
272
273 inarg->fh = ff->fh;
274 inarg->flags = flags;
275 req->in.h.opcode = opcode;
276 req->in.h.nodeid = ff->nodeid;
277 req->in.numargs = 1;
278 req->in.args[0].size = sizeof(struct fuse_release_in);
279 req->in.args[0].value = inarg;
280}
281
282void fuse_release_common(struct file *file, int opcode)
283{
284 struct fuse_file *ff;
285 struct fuse_req *req;
286
287 ff = file->private_data;
288 if (unlikely(!ff))
289 return;
290
291 req = ff->reserved_req;
292 fuse_prepare_release(ff, file->f_flags, opcode);
293
294 if (ff->flock) {
295 struct fuse_release_in *inarg = &req->misc.release.in;
296 inarg->release_flags |= FUSE_RELEASE_FLOCK_UNLOCK;
297 inarg->lock_owner = fuse_lock_owner_id(ff->fc,
298 (fl_owner_t) file);
299 }
300 /* Hold vfsmount and dentry until release is finished */
301 path_get(&file->f_path);
302 req->misc.release.path = file->f_path;
303
304 /*
305 * Normally this will send the RELEASE request, however if
306 * some asynchronous READ or WRITE requests are outstanding,
307 * the sending will be delayed.
308 *
309 * Make the release synchronous if this is a fuseblk mount,
310 * synchronous RELEASE is allowed (and desirable) in this case
311 * because the server can be trusted not to screw up.
312 */
313 fuse_file_put(ff, ff->fc->destroy_req != NULL);
314}
315
316static int fuse_open(struct inode *inode, struct file *file)
317{
318 return fuse_open_common(inode, file, false);
319}
320
321static int fuse_release(struct inode *inode, struct file *file)
322{
323 struct fuse_conn *fc = get_fuse_conn(inode);
324
325 /* see fuse_vma_close() for !writeback_cache case */
326 if (fc->writeback_cache)
327 write_inode_now(inode, 1);
328
329 fuse_release_common(file, FUSE_RELEASE);
330
331 /* return value is ignored by VFS */
332 return 0;
333}
334
335void fuse_sync_release(struct fuse_file *ff, int flags)
336{
337 WARN_ON(atomic_read(&ff->count) > 1);
338 fuse_prepare_release(ff, flags, FUSE_RELEASE);
339 ff->reserved_req->force = 1;
340 ff->reserved_req->background = 0;
341 fuse_request_send(ff->fc, ff->reserved_req);
342 fuse_put_request(ff->fc, ff->reserved_req);
343 kfree(ff);
344}
345EXPORT_SYMBOL_GPL(fuse_sync_release);
346
347/*
348 * Scramble the ID space with XTEA, so that the value of the files_struct
349 * pointer is not exposed to userspace.
350 */
351u64 fuse_lock_owner_id(struct fuse_conn *fc, fl_owner_t id)
352{
353 u32 *k = fc->scramble_key;
354 u64 v = (unsigned long) id;
355 u32 v0 = v;
356 u32 v1 = v >> 32;
357 u32 sum = 0;
358 int i;
359
360 for (i = 0; i < 32; i++) {
361 v0 += ((v1 << 4 ^ v1 >> 5) + v1) ^ (sum + k[sum & 3]);
362 sum += 0x9E3779B9;
363 v1 += ((v0 << 4 ^ v0 >> 5) + v0) ^ (sum + k[sum>>11 & 3]);
364 }
365
366 return (u64) v0 + ((u64) v1 << 32);
367}
368
369/*
370 * Check if any page in a range is under writeback
371 *
372 * This is currently done by walking the list of writepage requests
373 * for the inode, which can be pretty inefficient.
374 */
375static bool fuse_range_is_writeback(struct inode *inode, pgoff_t idx_from,
376 pgoff_t idx_to)
377{
378 struct fuse_conn *fc = get_fuse_conn(inode);
379 struct fuse_inode *fi = get_fuse_inode(inode);
380 struct fuse_req *req;
381 bool found = false;
382
383 spin_lock(&fc->lock);
384 list_for_each_entry(req, &fi->writepages, writepages_entry) {
385 pgoff_t curr_index;
386
387 BUG_ON(req->inode != inode);
388 curr_index = req->misc.write.in.offset >> PAGE_CACHE_SHIFT;
389 if (idx_from < curr_index + req->num_pages &&
390 curr_index <= idx_to) {
391 found = true;
392 break;
393 }
394 }
395 spin_unlock(&fc->lock);
396
397 return found;
398}
399
400static inline bool fuse_page_is_writeback(struct inode *inode, pgoff_t index)
401{
402 return fuse_range_is_writeback(inode, index, index);
403}
404
405/*
406 * Wait for page writeback to be completed.
407 *
408 * Since fuse doesn't rely on the VM writeback tracking, this has to
409 * use some other means.
410 */
411static int fuse_wait_on_page_writeback(struct inode *inode, pgoff_t index)
412{
413 struct fuse_inode *fi = get_fuse_inode(inode);
414
415 wait_event(fi->page_waitq, !fuse_page_is_writeback(inode, index));
416 return 0;
417}
418
419/*
420 * Wait for all pending writepages on the inode to finish.
421 *
422 * This is currently done by blocking further writes with FUSE_NOWRITE
423 * and waiting for all sent writes to complete.
424 *
425 * This must be called under i_mutex, otherwise the FUSE_NOWRITE usage
426 * could conflict with truncation.
427 */
428static void fuse_sync_writes(struct inode *inode)
429{
430 fuse_set_nowrite(inode);
431 fuse_release_nowrite(inode);
432}
433
434static int fuse_flush(struct file *file, fl_owner_t id)
435{
436 struct inode *inode = file_inode(file);
437 struct fuse_conn *fc = get_fuse_conn(inode);
438 struct fuse_file *ff = file->private_data;
439 struct fuse_req *req;
440 struct fuse_flush_in inarg;
441 int err;
442
443 if (is_bad_inode(inode))
444 return -EIO;
445
446 if (fc->no_flush)
447 return 0;
448
449 err = write_inode_now(inode, 1);
450 if (err)
451 return err;
452
453 mutex_lock(&inode->i_mutex);
454 fuse_sync_writes(inode);
455 mutex_unlock(&inode->i_mutex);
456
457 req = fuse_get_req_nofail_nopages(fc, file);
458 memset(&inarg, 0, sizeof(inarg));
459 inarg.fh = ff->fh;
460 inarg.lock_owner = fuse_lock_owner_id(fc, id);
461 req->in.h.opcode = FUSE_FLUSH;
462 req->in.h.nodeid = get_node_id(inode);
463 req->in.numargs = 1;
464 req->in.args[0].size = sizeof(inarg);
465 req->in.args[0].value = &inarg;
466 req->force = 1;
467 fuse_request_send(fc, req);
468 err = req->out.h.error;
469 fuse_put_request(fc, req);
470 if (err == -ENOSYS) {
471 fc->no_flush = 1;
472 err = 0;
473 }
474 return err;
475}
476
477int fuse_fsync_common(struct file *file, loff_t start, loff_t end,
478 int datasync, int isdir)
479{
480 struct inode *inode = file->f_mapping->host;
481 struct fuse_conn *fc = get_fuse_conn(inode);
482 struct fuse_file *ff = file->private_data;
483 struct fuse_req *req;
484 struct fuse_fsync_in inarg;
485 int err;
486
487 if (is_bad_inode(inode))
488 return -EIO;
489
490 mutex_lock(&inode->i_mutex);
491
492 /*
493 * Start writeback against all dirty pages of the inode, then
494 * wait for all outstanding writes, before sending the FSYNC
495 * request.
496 */
497 err = filemap_write_and_wait_range(inode->i_mapping, start, end);
498 if (err)
499 goto out;
500
501 fuse_sync_writes(inode);
502 err = sync_inode_metadata(inode, 1);
503 if (err)
504 goto out;
505
506 if ((!isdir && fc->no_fsync) || (isdir && fc->no_fsyncdir))
507 goto out;
508
509 req = fuse_get_req_nopages(fc);
510 if (IS_ERR(req)) {
511 err = PTR_ERR(req);
512 goto out;
513 }
514
515 memset(&inarg, 0, sizeof(inarg));
516 inarg.fh = ff->fh;
517 inarg.fsync_flags = datasync ? 1 : 0;
518 req->in.h.opcode = isdir ? FUSE_FSYNCDIR : FUSE_FSYNC;
519 req->in.h.nodeid = get_node_id(inode);
520 req->in.numargs = 1;
521 req->in.args[0].size = sizeof(inarg);
522 req->in.args[0].value = &inarg;
523 fuse_request_send(fc, req);
524 err = req->out.h.error;
525 fuse_put_request(fc, req);
526 if (err == -ENOSYS) {
527 if (isdir)
528 fc->no_fsyncdir = 1;
529 else
530 fc->no_fsync = 1;
531 err = 0;
532 }
533out:
534 mutex_unlock(&inode->i_mutex);
535 return err;
536}
537
538static int fuse_fsync(struct file *file, loff_t start, loff_t end,
539 int datasync)
540{
541 return fuse_fsync_common(file, start, end, datasync, 0);
542}
543
544void fuse_read_fill(struct fuse_req *req, struct file *file, loff_t pos,
545 size_t count, int opcode)
546{
547 struct fuse_read_in *inarg = &req->misc.read.in;
548 struct fuse_file *ff = file->private_data;
549
550 inarg->fh = ff->fh;
551 inarg->offset = pos;
552 inarg->size = count;
553 inarg->flags = file->f_flags;
554 req->in.h.opcode = opcode;
555 req->in.h.nodeid = ff->nodeid;
556 req->in.numargs = 1;
557 req->in.args[0].size = sizeof(struct fuse_read_in);
558 req->in.args[0].value = inarg;
559 req->out.argvar = 1;
560 req->out.numargs = 1;
561 req->out.args[0].size = count;
562}
563
564static void fuse_release_user_pages(struct fuse_req *req, int write)
565{
566 unsigned i;
567
568 for (i = 0; i < req->num_pages; i++) {
569 struct page *page = req->pages[i];
570 if (write)
571 set_page_dirty_lock(page);
572 put_page(page);
573 }
574}
575
576/**
577 * In case of short read, the caller sets 'pos' to the position of
578 * actual end of fuse request in IO request. Otherwise, if bytes_requested
579 * == bytes_transferred or rw == WRITE, the caller sets 'pos' to -1.
580 *
581 * An example:
582 * User requested DIO read of 64K. It was splitted into two 32K fuse requests,
583 * both submitted asynchronously. The first of them was ACKed by userspace as
584 * fully completed (req->out.args[0].size == 32K) resulting in pos == -1. The
585 * second request was ACKed as short, e.g. only 1K was read, resulting in
586 * pos == 33K.
587 *
588 * Thus, when all fuse requests are completed, the minimal non-negative 'pos'
589 * will be equal to the length of the longest contiguous fragment of
590 * transferred data starting from the beginning of IO request.
591 */
592static void fuse_aio_complete(struct fuse_io_priv *io, int err, ssize_t pos)
593{
594 int left;
595
596 spin_lock(&io->lock);
597 if (err)
598 io->err = io->err ? : err;
599 else if (pos >= 0 && (io->bytes < 0 || pos < io->bytes))
600 io->bytes = pos;
601
602 left = --io->reqs;
603 spin_unlock(&io->lock);
604
605 if (!left) {
606 long res;
607
608 if (io->err)
609 res = io->err;
610 else if (io->bytes >= 0 && io->write)
611 res = -EIO;
612 else {
613 res = io->bytes < 0 ? io->size : io->bytes;
614
615 if (!is_sync_kiocb(io->iocb)) {
616 struct inode *inode = file_inode(io->iocb->ki_filp);
617 struct fuse_conn *fc = get_fuse_conn(inode);
618 struct fuse_inode *fi = get_fuse_inode(inode);
619
620 spin_lock(&fc->lock);
621 fi->attr_version = ++fc->attr_version;
622 spin_unlock(&fc->lock);
623 }
624 }
625
626 aio_complete(io->iocb, res, 0);
627 kfree(io);
628 }
629}
630
631static void fuse_aio_complete_req(struct fuse_conn *fc, struct fuse_req *req)
632{
633 struct fuse_io_priv *io = req->io;
634 ssize_t pos = -1;
635
636 fuse_release_user_pages(req, !io->write);
637
638 if (io->write) {
639 if (req->misc.write.in.size != req->misc.write.out.size)
640 pos = req->misc.write.in.offset - io->offset +
641 req->misc.write.out.size;
642 } else {
643 if (req->misc.read.in.size != req->out.args[0].size)
644 pos = req->misc.read.in.offset - io->offset +
645 req->out.args[0].size;
646 }
647
648 fuse_aio_complete(io, req->out.h.error, pos);
649}
650
651static size_t fuse_async_req_send(struct fuse_conn *fc, struct fuse_req *req,
652 size_t num_bytes, struct fuse_io_priv *io)
653{
654 spin_lock(&io->lock);
655 io->size += num_bytes;
656 io->reqs++;
657 spin_unlock(&io->lock);
658
659 req->io = io;
660 req->end = fuse_aio_complete_req;
661
662 __fuse_get_request(req);
663 fuse_request_send_background(fc, req);
664
665 return num_bytes;
666}
667
668static size_t fuse_send_read(struct fuse_req *req, struct fuse_io_priv *io,
669 loff_t pos, size_t count, fl_owner_t owner)
670{
671 struct file *file = io->file;
672 struct fuse_file *ff = file->private_data;
673 struct fuse_conn *fc = ff->fc;
674
675 fuse_read_fill(req, file, pos, count, FUSE_READ);
676 if (owner != NULL) {
677 struct fuse_read_in *inarg = &req->misc.read.in;
678
679 inarg->read_flags |= FUSE_READ_LOCKOWNER;
680 inarg->lock_owner = fuse_lock_owner_id(fc, owner);
681 }
682
683 if (io->async)
684 return fuse_async_req_send(fc, req, count, io);
685
686 fuse_request_send(fc, req);
687 return req->out.args[0].size;
688}
689
690static void fuse_read_update_size(struct inode *inode, loff_t size,
691 u64 attr_ver)
692{
693 struct fuse_conn *fc = get_fuse_conn(inode);
694 struct fuse_inode *fi = get_fuse_inode(inode);
695
696 spin_lock(&fc->lock);
697 if (attr_ver == fi->attr_version && size < inode->i_size &&
698 !test_bit(FUSE_I_SIZE_UNSTABLE, &fi->state)) {
699 fi->attr_version = ++fc->attr_version;
700 i_size_write(inode, size);
701 }
702 spin_unlock(&fc->lock);
703}
704
705static void fuse_short_read(struct fuse_req *req, struct inode *inode,
706 u64 attr_ver)
707{
708 size_t num_read = req->out.args[0].size;
709 struct fuse_conn *fc = get_fuse_conn(inode);
710
711 if (fc->writeback_cache) {
712 /*
713 * A hole in a file. Some data after the hole are in page cache,
714 * but have not reached the client fs yet. So, the hole is not
715 * present there.
716 */
717 int i;
718 int start_idx = num_read >> PAGE_CACHE_SHIFT;
719 size_t off = num_read & (PAGE_CACHE_SIZE - 1);
720
721 for (i = start_idx; i < req->num_pages; i++) {
722 zero_user_segment(req->pages[i], off, PAGE_CACHE_SIZE);
723 off = 0;
724 }
725 } else {
726 loff_t pos = page_offset(req->pages[0]) + num_read;
727 fuse_read_update_size(inode, pos, attr_ver);
728 }
729}
730
731static int fuse_do_readpage(struct file *file, struct page *page)
732{
733 struct fuse_io_priv io = { .async = 0, .file = file };
734 struct inode *inode = page->mapping->host;
735 struct fuse_conn *fc = get_fuse_conn(inode);
736 struct fuse_req *req;
737 size_t num_read;
738 loff_t pos = page_offset(page);
739 size_t count = PAGE_CACHE_SIZE;
740 u64 attr_ver;
741 int err;
742
743 /*
744 * Page writeback can extend beyond the lifetime of the
745 * page-cache page, so make sure we read a properly synced
746 * page.
747 */
748 fuse_wait_on_page_writeback(inode, page->index);
749
750 req = fuse_get_req(fc, 1);
751 if (IS_ERR(req))
752 return PTR_ERR(req);
753
754 attr_ver = fuse_get_attr_version(fc);
755
756 req->out.page_zeroing = 1;
757 req->out.argpages = 1;
758 req->num_pages = 1;
759 req->pages[0] = page;
760 req->page_descs[0].length = count;
761 num_read = fuse_send_read(req, &io, pos, count, NULL);
762 err = req->out.h.error;
763
764 if (!err) {
765 /*
766 * Short read means EOF. If file size is larger, truncate it
767 */
768 if (num_read < count)
769 fuse_short_read(req, inode, attr_ver);
770
771 SetPageUptodate(page);
772 }
773
774 fuse_put_request(fc, req);
775
776 return err;
777}
778
779static int fuse_readpage(struct file *file, struct page *page)
780{
781 struct inode *inode = page->mapping->host;
782 int err;
783
784 err = -EIO;
785 if (is_bad_inode(inode))
786 goto out;
787
788 err = fuse_do_readpage(file, page);
789 fuse_invalidate_atime(inode);
790 out:
791 unlock_page(page);
792 return err;
793}
794
795static void fuse_readpages_end(struct fuse_conn *fc, struct fuse_req *req)
796{
797 int i;
798 size_t count = req->misc.read.in.size;
799 size_t num_read = req->out.args[0].size;
800 struct address_space *mapping = NULL;
801
802 for (i = 0; mapping == NULL && i < req->num_pages; i++)
803 mapping = req->pages[i]->mapping;
804
805 if (mapping) {
806 struct inode *inode = mapping->host;
807
808 /*
809 * Short read means EOF. If file size is larger, truncate it
810 */
811 if (!req->out.h.error && num_read < count)
812 fuse_short_read(req, inode, req->misc.read.attr_ver);
813
814 fuse_invalidate_atime(inode);
815 }
816
817 for (i = 0; i < req->num_pages; i++) {
818 struct page *page = req->pages[i];
819 if (!req->out.h.error)
820 SetPageUptodate(page);
821 else
822 SetPageError(page);
823 unlock_page(page);
824 page_cache_release(page);
825 }
826 if (req->ff)
827 fuse_file_put(req->ff, false);
828}
829
830static void fuse_send_readpages(struct fuse_req *req, struct file *file)
831{
832 struct fuse_file *ff = file->private_data;
833 struct fuse_conn *fc = ff->fc;
834 loff_t pos = page_offset(req->pages[0]);
835 size_t count = req->num_pages << PAGE_CACHE_SHIFT;
836
837 req->out.argpages = 1;
838 req->out.page_zeroing = 1;
839 req->out.page_replace = 1;
840 fuse_read_fill(req, file, pos, count, FUSE_READ);
841 req->misc.read.attr_ver = fuse_get_attr_version(fc);
842 if (fc->async_read) {
843 req->ff = fuse_file_get(ff);
844 req->end = fuse_readpages_end;
845 fuse_request_send_background(fc, req);
846 } else {
847 fuse_request_send(fc, req);
848 fuse_readpages_end(fc, req);
849 fuse_put_request(fc, req);
850 }
851}
852
853struct fuse_fill_data {
854 struct fuse_req *req;
855 struct file *file;
856 struct inode *inode;
857 unsigned nr_pages;
858};
859
860static int fuse_readpages_fill(void *_data, struct page *page)
861{
862 struct fuse_fill_data *data = _data;
863 struct fuse_req *req = data->req;
864 struct inode *inode = data->inode;
865 struct fuse_conn *fc = get_fuse_conn(inode);
866
867 fuse_wait_on_page_writeback(inode, page->index);
868
869 if (req->num_pages &&
870 (req->num_pages == FUSE_MAX_PAGES_PER_REQ ||
871 (req->num_pages + 1) * PAGE_CACHE_SIZE > fc->max_read ||
872 req->pages[req->num_pages - 1]->index + 1 != page->index)) {
873 int nr_alloc = min_t(unsigned, data->nr_pages,
874 FUSE_MAX_PAGES_PER_REQ);
875 fuse_send_readpages(req, data->file);
876 if (fc->async_read)
877 req = fuse_get_req_for_background(fc, nr_alloc);
878 else
879 req = fuse_get_req(fc, nr_alloc);
880
881 data->req = req;
882 if (IS_ERR(req)) {
883 unlock_page(page);
884 return PTR_ERR(req);
885 }
886 }
887
888 if (WARN_ON(req->num_pages >= req->max_pages)) {
889 fuse_put_request(fc, req);
890 return -EIO;
891 }
892
893 page_cache_get(page);
894 req->pages[req->num_pages] = page;
895 req->page_descs[req->num_pages].length = PAGE_SIZE;
896 req->num_pages++;
897 data->nr_pages--;
898 return 0;
899}
900
901static int fuse_readpages(struct file *file, struct address_space *mapping,
902 struct list_head *pages, unsigned nr_pages)
903{
904 struct inode *inode = mapping->host;
905 struct fuse_conn *fc = get_fuse_conn(inode);
906 struct fuse_fill_data data;
907 int err;
908 int nr_alloc = min_t(unsigned, nr_pages, FUSE_MAX_PAGES_PER_REQ);
909
910 err = -EIO;
911 if (is_bad_inode(inode))
912 goto out;
913
914 data.file = file;
915 data.inode = inode;
916 if (fc->async_read)
917 data.req = fuse_get_req_for_background(fc, nr_alloc);
918 else
919 data.req = fuse_get_req(fc, nr_alloc);
920 data.nr_pages = nr_pages;
921 err = PTR_ERR(data.req);
922 if (IS_ERR(data.req))
923 goto out;
924
925 err = read_cache_pages(mapping, pages, fuse_readpages_fill, &data);
926 if (!err) {
927 if (data.req->num_pages)
928 fuse_send_readpages(data.req, file);
929 else
930 fuse_put_request(fc, data.req);
931 }
932out:
933 return err;
934}
935
936static ssize_t fuse_file_aio_read(struct kiocb *iocb, const struct iovec *iov,
937 unsigned long nr_segs, loff_t pos)
938{
939 struct inode *inode = iocb->ki_filp->f_mapping->host;
940 struct fuse_conn *fc = get_fuse_conn(inode);
941
942 /*
943 * In auto invalidate mode, always update attributes on read.
944 * Otherwise, only update if we attempt to read past EOF (to ensure
945 * i_size is up to date).
946 */
947 if (fc->auto_inval_data ||
948 (pos + iov_length(iov, nr_segs) > i_size_read(inode))) {
949 int err;
950 err = fuse_update_attributes(inode, NULL, iocb->ki_filp, NULL);
951 if (err)
952 return err;
953 }
954
955 return generic_file_aio_read(iocb, iov, nr_segs, pos);
956}
957
958static void fuse_write_fill(struct fuse_req *req, struct fuse_file *ff,
959 loff_t pos, size_t count)
960{
961 struct fuse_write_in *inarg = &req->misc.write.in;
962 struct fuse_write_out *outarg = &req->misc.write.out;
963
964 inarg->fh = ff->fh;
965 inarg->offset = pos;
966 inarg->size = count;
967 req->in.h.opcode = FUSE_WRITE;
968 req->in.h.nodeid = ff->nodeid;
969 req->in.numargs = 2;
970 if (ff->fc->minor < 9)
971 req->in.args[0].size = FUSE_COMPAT_WRITE_IN_SIZE;
972 else
973 req->in.args[0].size = sizeof(struct fuse_write_in);
974 req->in.args[0].value = inarg;
975 req->in.args[1].size = count;
976 req->out.numargs = 1;
977 req->out.args[0].size = sizeof(struct fuse_write_out);
978 req->out.args[0].value = outarg;
979}
980
981static size_t fuse_send_write(struct fuse_req *req, struct fuse_io_priv *io,
982 loff_t pos, size_t count, fl_owner_t owner)
983{
984 struct file *file = io->file;
985 struct fuse_file *ff = file->private_data;
986 struct fuse_conn *fc = ff->fc;
987 struct fuse_write_in *inarg = &req->misc.write.in;
988
989 fuse_write_fill(req, ff, pos, count);
990 inarg->flags = file->f_flags;
991 if (owner != NULL) {
992 inarg->write_flags |= FUSE_WRITE_LOCKOWNER;
993 inarg->lock_owner = fuse_lock_owner_id(fc, owner);
994 }
995
996 if (io->async)
997 return fuse_async_req_send(fc, req, count, io);
998
999 fuse_request_send(fc, req);
1000 return req->misc.write.out.size;
1001}
1002
1003bool fuse_write_update_size(struct inode *inode, loff_t pos)
1004{
1005 struct fuse_conn *fc = get_fuse_conn(inode);
1006 struct fuse_inode *fi = get_fuse_inode(inode);
1007 bool ret = false;
1008
1009 spin_lock(&fc->lock);
1010 fi->attr_version = ++fc->attr_version;
1011 if (pos > inode->i_size) {
1012 i_size_write(inode, pos);
1013 ret = true;
1014 }
1015 spin_unlock(&fc->lock);
1016
1017 return ret;
1018}
1019
1020static size_t fuse_send_write_pages(struct fuse_req *req, struct file *file,
1021 struct inode *inode, loff_t pos,
1022 size_t count)
1023{
1024 size_t res;
1025 unsigned offset;
1026 unsigned i;
1027 struct fuse_io_priv io = { .async = 0, .file = file };
1028
1029 for (i = 0; i < req->num_pages; i++)
1030 fuse_wait_on_page_writeback(inode, req->pages[i]->index);
1031
1032 res = fuse_send_write(req, &io, pos, count, NULL);
1033
1034 offset = req->page_descs[0].offset;
1035 count = res;
1036 for (i = 0; i < req->num_pages; i++) {
1037 struct page *page = req->pages[i];
1038
1039 if (!req->out.h.error && !offset && count >= PAGE_CACHE_SIZE)
1040 SetPageUptodate(page);
1041
1042 if (count > PAGE_CACHE_SIZE - offset)
1043 count -= PAGE_CACHE_SIZE - offset;
1044 else
1045 count = 0;
1046 offset = 0;
1047
1048 unlock_page(page);
1049 page_cache_release(page);
1050 }
1051
1052 return res;
1053}
1054
1055static ssize_t fuse_fill_write_pages(struct fuse_req *req,
1056 struct address_space *mapping,
1057 struct iov_iter *ii, loff_t pos)
1058{
1059 struct fuse_conn *fc = get_fuse_conn(mapping->host);
1060 unsigned offset = pos & (PAGE_CACHE_SIZE - 1);
1061 size_t count = 0;
1062 int err;
1063
1064 req->in.argpages = 1;
1065 req->page_descs[0].offset = offset;
1066
1067 do {
1068 size_t tmp;
1069 struct page *page;
1070 pgoff_t index = pos >> PAGE_CACHE_SHIFT;
1071 size_t bytes = min_t(size_t, PAGE_CACHE_SIZE - offset,
1072 iov_iter_count(ii));
1073
1074 bytes = min_t(size_t, bytes, fc->max_write - count);
1075
1076 again:
1077 err = -EFAULT;
1078 if (iov_iter_fault_in_readable(ii, bytes))
1079 break;
1080
1081 err = -ENOMEM;
1082 page = grab_cache_page_write_begin(mapping, index, 0);
1083 if (!page)
1084 break;
1085
1086 if (mapping_writably_mapped(mapping))
1087 flush_dcache_page(page);
1088
1089 tmp = iov_iter_copy_from_user_atomic(page, ii, offset, bytes);
1090 flush_dcache_page(page);
1091
1092 mark_page_accessed(page);
1093
1094 if (!tmp) {
1095 unlock_page(page);
1096 page_cache_release(page);
1097 bytes = min(bytes, iov_iter_single_seg_count(ii));
1098 goto again;
1099 }
1100
1101 err = 0;
1102 req->pages[req->num_pages] = page;
1103 req->page_descs[req->num_pages].length = tmp;
1104 req->num_pages++;
1105
1106 iov_iter_advance(ii, tmp);
1107 count += tmp;
1108 pos += tmp;
1109 offset += tmp;
1110 if (offset == PAGE_CACHE_SIZE)
1111 offset = 0;
1112
1113 if (!fc->big_writes)
1114 break;
1115 } while (iov_iter_count(ii) && count < fc->max_write &&
1116 req->num_pages < req->max_pages && offset == 0);
1117
1118 return count > 0 ? count : err;
1119}
1120
1121static inline unsigned fuse_wr_pages(loff_t pos, size_t len)
1122{
1123 return min_t(unsigned,
1124 ((pos + len - 1) >> PAGE_CACHE_SHIFT) -
1125 (pos >> PAGE_CACHE_SHIFT) + 1,
1126 FUSE_MAX_PAGES_PER_REQ);
1127}
1128
1129static ssize_t fuse_perform_write(struct file *file,
1130 struct address_space *mapping,
1131 struct iov_iter *ii, loff_t pos)
1132{
1133 struct inode *inode = mapping->host;
1134 struct fuse_conn *fc = get_fuse_conn(inode);
1135 struct fuse_inode *fi = get_fuse_inode(inode);
1136 int err = 0;
1137 ssize_t res = 0;
1138
1139 if (is_bad_inode(inode))
1140 return -EIO;
1141
1142 if (inode->i_size < pos + iov_iter_count(ii))
1143 set_bit(FUSE_I_SIZE_UNSTABLE, &fi->state);
1144
1145 do {
1146 struct fuse_req *req;
1147 ssize_t count;
1148 unsigned nr_pages = fuse_wr_pages(pos, iov_iter_count(ii));
1149
1150 req = fuse_get_req(fc, nr_pages);
1151 if (IS_ERR(req)) {
1152 err = PTR_ERR(req);
1153 break;
1154 }
1155
1156 count = fuse_fill_write_pages(req, mapping, ii, pos);
1157 if (count <= 0) {
1158 err = count;
1159 } else {
1160 size_t num_written;
1161
1162 num_written = fuse_send_write_pages(req, file, inode,
1163 pos, count);
1164 err = req->out.h.error;
1165 if (!err) {
1166 res += num_written;
1167 pos += num_written;
1168
1169 /* break out of the loop on short write */
1170 if (num_written != count)
1171 err = -EIO;
1172 }
1173 }
1174 fuse_put_request(fc, req);
1175 } while (!err && iov_iter_count(ii));
1176
1177 if (res > 0)
1178 fuse_write_update_size(inode, pos);
1179
1180 clear_bit(FUSE_I_SIZE_UNSTABLE, &fi->state);
1181 fuse_invalidate_attr(inode);
1182
1183 return res > 0 ? res : err;
1184}
1185
1186static ssize_t fuse_file_aio_write(struct kiocb *iocb, const struct iovec *iov,
1187 unsigned long nr_segs, loff_t pos)
1188{
1189 struct file *file = iocb->ki_filp;
1190 struct address_space *mapping = file->f_mapping;
1191 size_t count = 0;
1192 size_t ocount = 0;
1193 ssize_t written = 0;
1194 ssize_t written_buffered = 0;
1195 struct inode *inode = mapping->host;
1196 ssize_t err;
1197 struct iov_iter i;
1198 loff_t endbyte = 0;
1199
1200 if (get_fuse_conn(inode)->writeback_cache) {
1201 /* Update size (EOF optimization) and mode (SUID clearing) */
1202 err = fuse_update_attributes(mapping->host, NULL, file, NULL);
1203 if (err)
1204 return err;
1205
1206 return generic_file_aio_write(iocb, iov, nr_segs, pos);
1207 }
1208
1209 WARN_ON(iocb->ki_pos != pos);
1210
1211 ocount = 0;
1212 err = generic_segment_checks(iov, &nr_segs, &ocount, VERIFY_READ);
1213 if (err)
1214 return err;
1215
1216 count = ocount;
1217 mutex_lock(&inode->i_mutex);
1218
1219 /* We can write back this queue in page reclaim */
1220 current->backing_dev_info = mapping->backing_dev_info;
1221
1222 err = generic_write_checks(file, &pos, &count, S_ISBLK(inode->i_mode));
1223 if (err)
1224 goto out;
1225
1226 if (count == 0)
1227 goto out;
1228
1229 err = file_remove_suid(file);
1230 if (err)
1231 goto out;
1232
1233 err = file_update_time(file);
1234 if (err)
1235 goto out;
1236
1237 if (file->f_flags & O_DIRECT) {
1238 written = generic_file_direct_write(iocb, iov, &nr_segs, pos,
1239 count, ocount);
1240 if (written < 0 || written == count)
1241 goto out;
1242
1243 pos += written;
1244 count -= written;
1245
1246 iov_iter_init(&i, iov, nr_segs, count, written);
1247 written_buffered = fuse_perform_write(file, mapping, &i, pos);
1248 if (written_buffered < 0) {
1249 err = written_buffered;
1250 goto out;
1251 }
1252 endbyte = pos + written_buffered - 1;
1253
1254 err = filemap_write_and_wait_range(file->f_mapping, pos,
1255 endbyte);
1256 if (err)
1257 goto out;
1258
1259 invalidate_mapping_pages(file->f_mapping,
1260 pos >> PAGE_CACHE_SHIFT,
1261 endbyte >> PAGE_CACHE_SHIFT);
1262
1263 written += written_buffered;
1264 iocb->ki_pos = pos + written_buffered;
1265 } else {
1266 iov_iter_init(&i, iov, nr_segs, count, 0);
1267 written = fuse_perform_write(file, mapping, &i, pos);
1268 if (written >= 0)
1269 iocb->ki_pos = pos + written;
1270 }
1271out:
1272 current->backing_dev_info = NULL;
1273 mutex_unlock(&inode->i_mutex);
1274
1275 return written ? written : err;
1276}
1277
1278static inline void fuse_page_descs_length_init(struct fuse_req *req,
1279 unsigned index, unsigned nr_pages)
1280{
1281 int i;
1282
1283 for (i = index; i < index + nr_pages; i++)
1284 req->page_descs[i].length = PAGE_SIZE -
1285 req->page_descs[i].offset;
1286}
1287
1288static inline unsigned long fuse_get_user_addr(const struct iov_iter *ii)
1289{
1290 return (unsigned long)ii->iov->iov_base + ii->iov_offset;
1291}
1292
1293static inline size_t fuse_get_frag_size(const struct iov_iter *ii,
1294 size_t max_size)
1295{
1296 return min(iov_iter_single_seg_count(ii), max_size);
1297}
1298
1299static int fuse_get_user_pages(struct fuse_req *req, struct iov_iter *ii,
1300 size_t *nbytesp, int write)
1301{
1302 size_t nbytes = 0; /* # bytes already packed in req */
1303
1304 /* Special case for kernel I/O: can copy directly into the buffer */
1305 if (segment_eq(get_fs(), KERNEL_DS)) {
1306 unsigned long user_addr = fuse_get_user_addr(ii);
1307 size_t frag_size = fuse_get_frag_size(ii, *nbytesp);
1308
1309 if (write)
1310 req->in.args[1].value = (void *) user_addr;
1311 else
1312 req->out.args[0].value = (void *) user_addr;
1313
1314 iov_iter_advance(ii, frag_size);
1315 *nbytesp = frag_size;
1316 return 0;
1317 }
1318
1319 while (nbytes < *nbytesp && req->num_pages < req->max_pages) {
1320 unsigned npages;
1321 unsigned long user_addr = fuse_get_user_addr(ii);
1322 unsigned offset = user_addr & ~PAGE_MASK;
1323 size_t frag_size = fuse_get_frag_size(ii, *nbytesp - nbytes);
1324 int ret;
1325
1326 unsigned n = req->max_pages - req->num_pages;
1327 frag_size = min_t(size_t, frag_size, n << PAGE_SHIFT);
1328
1329 npages = (frag_size + offset + PAGE_SIZE - 1) >> PAGE_SHIFT;
1330 npages = clamp(npages, 1U, n);
1331
1332 ret = get_user_pages_fast(user_addr, npages, !write,
1333 &req->pages[req->num_pages]);
1334 if (ret < 0)
1335 return ret;
1336
1337 npages = ret;
1338 frag_size = min_t(size_t, frag_size,
1339 (npages << PAGE_SHIFT) - offset);
1340 iov_iter_advance(ii, frag_size);
1341
1342 req->page_descs[req->num_pages].offset = offset;
1343 fuse_page_descs_length_init(req, req->num_pages, npages);
1344
1345 req->num_pages += npages;
1346 req->page_descs[req->num_pages - 1].length -=
1347 (npages << PAGE_SHIFT) - offset - frag_size;
1348
1349 nbytes += frag_size;
1350 }
1351
1352 if (write)
1353 req->in.argpages = 1;
1354 else
1355 req->out.argpages = 1;
1356
1357 *nbytesp = nbytes;
1358
1359 return 0;
1360}
1361
1362static inline int fuse_iter_npages(const struct iov_iter *ii_p)
1363{
1364 struct iov_iter ii = *ii_p;
1365 int npages = 0;
1366
1367 while (iov_iter_count(&ii) && npages < FUSE_MAX_PAGES_PER_REQ) {
1368 unsigned long user_addr = fuse_get_user_addr(&ii);
1369 unsigned offset = user_addr & ~PAGE_MASK;
1370 size_t frag_size = iov_iter_single_seg_count(&ii);
1371
1372 npages += (frag_size + offset + PAGE_SIZE - 1) >> PAGE_SHIFT;
1373 iov_iter_advance(&ii, frag_size);
1374 }
1375
1376 return min(npages, FUSE_MAX_PAGES_PER_REQ);
1377}
1378
1379ssize_t fuse_direct_io(struct fuse_io_priv *io, const struct iovec *iov,
1380 unsigned long nr_segs, size_t count, loff_t *ppos,
1381 int flags)
1382{
1383 int write = flags & FUSE_DIO_WRITE;
1384 int cuse = flags & FUSE_DIO_CUSE;
1385 struct file *file = io->file;
1386 struct inode *inode = file->f_mapping->host;
1387 struct fuse_file *ff = file->private_data;
1388 struct fuse_conn *fc = ff->fc;
1389 size_t nmax = write ? fc->max_write : fc->max_read;
1390 loff_t pos = *ppos;
1391 pgoff_t idx_from = pos >> PAGE_CACHE_SHIFT;
1392 pgoff_t idx_to = (pos + count - 1) >> PAGE_CACHE_SHIFT;
1393 ssize_t res = 0;
1394 struct fuse_req *req;
1395 struct iov_iter ii;
1396
1397 iov_iter_init(&ii, iov, nr_segs, count, 0);
1398
1399 if (io->async)
1400 req = fuse_get_req_for_background(fc, fuse_iter_npages(&ii));
1401 else
1402 req = fuse_get_req(fc, fuse_iter_npages(&ii));
1403 if (IS_ERR(req))
1404 return PTR_ERR(req);
1405
1406 if (!cuse && fuse_range_is_writeback(inode, idx_from, idx_to)) {
1407 if (!write)
1408 mutex_lock(&inode->i_mutex);
1409 fuse_sync_writes(inode);
1410 if (!write)
1411 mutex_unlock(&inode->i_mutex);
1412 }
1413
1414 while (count) {
1415 size_t nres;
1416 fl_owner_t owner = current->files;
1417 size_t nbytes = min(count, nmax);
1418 int err = fuse_get_user_pages(req, &ii, &nbytes, write);
1419 if (err) {
1420 res = err;
1421 break;
1422 }
1423
1424 if (write)
1425 nres = fuse_send_write(req, io, pos, nbytes, owner);
1426 else
1427 nres = fuse_send_read(req, io, pos, nbytes, owner);
1428
1429 if (!io->async)
1430 fuse_release_user_pages(req, !write);
1431 if (req->out.h.error) {
1432 if (!res)
1433 res = req->out.h.error;
1434 break;
1435 } else if (nres > nbytes) {
1436 res = -EIO;
1437 break;
1438 }
1439 count -= nres;
1440 res += nres;
1441 pos += nres;
1442 if (nres != nbytes)
1443 break;
1444 if (count) {
1445 fuse_put_request(fc, req);
1446 if (io->async)
1447 req = fuse_get_req_for_background(fc,
1448 fuse_iter_npages(&ii));
1449 else
1450 req = fuse_get_req(fc, fuse_iter_npages(&ii));
1451 if (IS_ERR(req))
1452 break;
1453 }
1454 }
1455 if (!IS_ERR(req))
1456 fuse_put_request(fc, req);
1457 if (res > 0)
1458 *ppos = pos;
1459
1460 return res;
1461}
1462EXPORT_SYMBOL_GPL(fuse_direct_io);
1463
1464static ssize_t __fuse_direct_read(struct fuse_io_priv *io,
1465 const struct iovec *iov,
1466 unsigned long nr_segs, loff_t *ppos,
1467 size_t count)
1468{
1469 ssize_t res;
1470 struct file *file = io->file;
1471 struct inode *inode = file_inode(file);
1472
1473 if (is_bad_inode(inode))
1474 return -EIO;
1475
1476 res = fuse_direct_io(io, iov, nr_segs, count, ppos, 0);
1477
1478 fuse_invalidate_attr(inode);
1479
1480 return res;
1481}
1482
1483static ssize_t fuse_direct_read(struct file *file, char __user *buf,
1484 size_t count, loff_t *ppos)
1485{
1486 struct fuse_io_priv io = { .async = 0, .file = file };
1487 struct iovec iov = { .iov_base = buf, .iov_len = count };
1488 return __fuse_direct_read(&io, &iov, 1, ppos, count);
1489}
1490
1491static ssize_t __fuse_direct_write(struct fuse_io_priv *io,
1492 const struct iovec *iov,
1493 unsigned long nr_segs, loff_t *ppos)
1494{
1495 struct file *file = io->file;
1496 struct inode *inode = file_inode(file);
1497 size_t count = iov_length(iov, nr_segs);
1498 ssize_t res;
1499
1500 res = generic_write_checks(file, ppos, &count, 0);
1501 if (!res)
1502 res = fuse_direct_io(io, iov, nr_segs, count, ppos,
1503 FUSE_DIO_WRITE);
1504
1505 fuse_invalidate_attr(inode);
1506
1507 return res;
1508}
1509
1510static ssize_t fuse_direct_write(struct file *file, const char __user *buf,
1511 size_t count, loff_t *ppos)
1512{
1513 struct iovec iov = { .iov_base = (void __user *)buf, .iov_len = count };
1514 struct inode *inode = file_inode(file);
1515 ssize_t res;
1516 struct fuse_io_priv io = { .async = 0, .file = file };
1517
1518 if (is_bad_inode(inode))
1519 return -EIO;
1520
1521 /* Don't allow parallel writes to the same file */
1522 mutex_lock(&inode->i_mutex);
1523 res = __fuse_direct_write(&io, &iov, 1, ppos);
1524 if (res > 0)
1525 fuse_write_update_size(inode, *ppos);
1526 mutex_unlock(&inode->i_mutex);
1527
1528 return res;
1529}
1530
1531static void fuse_writepage_free(struct fuse_conn *fc, struct fuse_req *req)
1532{
1533 int i;
1534
1535 for (i = 0; i < req->num_pages; i++)
1536 __free_page(req->pages[i]);
1537
1538 if (req->ff)
1539 fuse_file_put(req->ff, false);
1540}
1541
1542static void fuse_writepage_finish(struct fuse_conn *fc, struct fuse_req *req)
1543{
1544 struct inode *inode = req->inode;
1545 struct fuse_inode *fi = get_fuse_inode(inode);
1546 struct backing_dev_info *bdi = inode->i_mapping->backing_dev_info;
1547 int i;
1548
1549 list_del(&req->writepages_entry);
1550 for (i = 0; i < req->num_pages; i++) {
1551 dec_bdi_stat(bdi, BDI_WRITEBACK);
1552 dec_zone_page_state(req->pages[i], NR_WRITEBACK_TEMP);
1553 bdi_writeout_inc(bdi);
1554 }
1555 wake_up(&fi->page_waitq);
1556}
1557
1558/* Called under fc->lock, may release and reacquire it */
1559static void fuse_send_writepage(struct fuse_conn *fc, struct fuse_req *req,
1560 loff_t size)
1561__releases(fc->lock)
1562__acquires(fc->lock)
1563{
1564 struct fuse_inode *fi = get_fuse_inode(req->inode);
1565 struct fuse_write_in *inarg = &req->misc.write.in;
1566 __u64 data_size = req->num_pages * PAGE_CACHE_SIZE;
1567
1568 if (!fc->connected)
1569 goto out_free;
1570
1571 if (inarg->offset + data_size <= size) {
1572 inarg->size = data_size;
1573 } else if (inarg->offset < size) {
1574 inarg->size = size - inarg->offset;
1575 } else {
1576 /* Got truncated off completely */
1577 goto out_free;
1578 }
1579
1580 req->in.args[1].size = inarg->size;
1581 fi->writectr++;
1582 fuse_request_send_background_locked(fc, req);
1583 return;
1584
1585 out_free:
1586 fuse_writepage_finish(fc, req);
1587 spin_unlock(&fc->lock);
1588 fuse_writepage_free(fc, req);
1589 fuse_put_request(fc, req);
1590 spin_lock(&fc->lock);
1591}
1592
1593/*
1594 * If fi->writectr is positive (no truncate or fsync going on) send
1595 * all queued writepage requests.
1596 *
1597 * Called with fc->lock
1598 */
1599void fuse_flush_writepages(struct inode *inode)
1600__releases(fc->lock)
1601__acquires(fc->lock)
1602{
1603 struct fuse_conn *fc = get_fuse_conn(inode);
1604 struct fuse_inode *fi = get_fuse_inode(inode);
1605 size_t crop = i_size_read(inode);
1606 struct fuse_req *req;
1607
1608 while (fi->writectr >= 0 && !list_empty(&fi->queued_writes)) {
1609 req = list_entry(fi->queued_writes.next, struct fuse_req, list);
1610 list_del_init(&req->list);
1611 fuse_send_writepage(fc, req, crop);
1612 }
1613}
1614
1615static void fuse_writepage_end(struct fuse_conn *fc, struct fuse_req *req)
1616{
1617 struct inode *inode = req->inode;
1618 struct fuse_inode *fi = get_fuse_inode(inode);
1619
1620 mapping_set_error(inode->i_mapping, req->out.h.error);
1621 spin_lock(&fc->lock);
1622 while (req->misc.write.next) {
1623 struct fuse_conn *fc = get_fuse_conn(inode);
1624 struct fuse_write_in *inarg = &req->misc.write.in;
1625 struct fuse_req *next = req->misc.write.next;
1626 req->misc.write.next = next->misc.write.next;
1627 next->misc.write.next = NULL;
1628 next->ff = fuse_file_get(req->ff);
1629 list_add(&next->writepages_entry, &fi->writepages);
1630
1631 /*
1632 * Skip fuse_flush_writepages() to make it easy to crop requests
1633 * based on primary request size.
1634 *
1635 * 1st case (trivial): there are no concurrent activities using
1636 * fuse_set/release_nowrite. Then we're on safe side because
1637 * fuse_flush_writepages() would call fuse_send_writepage()
1638 * anyway.
1639 *
1640 * 2nd case: someone called fuse_set_nowrite and it is waiting
1641 * now for completion of all in-flight requests. This happens
1642 * rarely and no more than once per page, so this should be
1643 * okay.
1644 *
1645 * 3rd case: someone (e.g. fuse_do_setattr()) is in the middle
1646 * of fuse_set_nowrite..fuse_release_nowrite section. The fact
1647 * that fuse_set_nowrite returned implies that all in-flight
1648 * requests were completed along with all of their secondary
1649 * requests. Further primary requests are blocked by negative
1650 * writectr. Hence there cannot be any in-flight requests and
1651 * no invocations of fuse_writepage_end() while we're in
1652 * fuse_set_nowrite..fuse_release_nowrite section.
1653 */
1654 fuse_send_writepage(fc, next, inarg->offset + inarg->size);
1655 }
1656 fi->writectr--;
1657 fuse_writepage_finish(fc, req);
1658 spin_unlock(&fc->lock);
1659 fuse_writepage_free(fc, req);
1660}
1661
1662static struct fuse_file *__fuse_write_file_get(struct fuse_conn *fc,
1663 struct fuse_inode *fi)
1664{
1665 struct fuse_file *ff = NULL;
1666
1667 spin_lock(&fc->lock);
1668 if (!list_empty(&fi->write_files)) {
1669 ff = list_entry(fi->write_files.next, struct fuse_file,
1670 write_entry);
1671 fuse_file_get(ff);
1672 }
1673 spin_unlock(&fc->lock);
1674
1675 return ff;
1676}
1677
1678static struct fuse_file *fuse_write_file_get(struct fuse_conn *fc,
1679 struct fuse_inode *fi)
1680{
1681 struct fuse_file *ff = __fuse_write_file_get(fc, fi);
1682 WARN_ON(!ff);
1683 return ff;
1684}
1685
1686int fuse_write_inode(struct inode *inode, struct writeback_control *wbc)
1687{
1688 struct fuse_conn *fc = get_fuse_conn(inode);
1689 struct fuse_inode *fi = get_fuse_inode(inode);
1690 struct fuse_file *ff;
1691 int err;
1692
1693 ff = __fuse_write_file_get(fc, fi);
1694 err = fuse_flush_times(inode, ff);
1695 if (ff)
1696 fuse_file_put(ff, 0);
1697
1698 return err;
1699}
1700
1701static int fuse_writepage_locked(struct page *page)
1702{
1703 struct address_space *mapping = page->mapping;
1704 struct inode *inode = mapping->host;
1705 struct fuse_conn *fc = get_fuse_conn(inode);
1706 struct fuse_inode *fi = get_fuse_inode(inode);
1707 struct fuse_req *req;
1708 struct page *tmp_page;
1709 int error = -ENOMEM;
1710
1711 set_page_writeback(page);
1712
1713 req = fuse_request_alloc_nofs(1);
1714 if (!req)
1715 goto err;
1716
1717 req->background = 1; /* writeback always goes to bg_queue */
1718 tmp_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
1719 if (!tmp_page)
1720 goto err_free;
1721
1722 error = -EIO;
1723 req->ff = fuse_write_file_get(fc, fi);
1724 if (!req->ff)
1725 goto err_free;
1726
1727 fuse_write_fill(req, req->ff, page_offset(page), 0);
1728
1729 copy_highpage(tmp_page, page);
1730 req->misc.write.in.write_flags |= FUSE_WRITE_CACHE;
1731 req->misc.write.next = NULL;
1732 req->in.argpages = 1;
1733 req->num_pages = 1;
1734 req->pages[0] = tmp_page;
1735 req->page_descs[0].offset = 0;
1736 req->page_descs[0].length = PAGE_SIZE;
1737 req->end = fuse_writepage_end;
1738 req->inode = inode;
1739
1740 inc_bdi_stat(mapping->backing_dev_info, BDI_WRITEBACK);
1741 inc_zone_page_state(tmp_page, NR_WRITEBACK_TEMP);
1742
1743 spin_lock(&fc->lock);
1744 list_add(&req->writepages_entry, &fi->writepages);
1745 list_add_tail(&req->list, &fi->queued_writes);
1746 fuse_flush_writepages(inode);
1747 spin_unlock(&fc->lock);
1748
1749 end_page_writeback(page);
1750
1751 return 0;
1752
1753err_free:
1754 fuse_request_free(req);
1755err:
1756 end_page_writeback(page);
1757 return error;
1758}
1759
1760static int fuse_writepage(struct page *page, struct writeback_control *wbc)
1761{
1762 int err;
1763
1764 if (fuse_page_is_writeback(page->mapping->host, page->index)) {
1765 /*
1766 * ->writepages() should be called for sync() and friends. We
1767 * should only get here on direct reclaim and then we are
1768 * allowed to skip a page which is already in flight
1769 */
1770 WARN_ON(wbc->sync_mode == WB_SYNC_ALL);
1771
1772 redirty_page_for_writepage(wbc, page);
1773 return 0;
1774 }
1775
1776 err = fuse_writepage_locked(page);
1777 unlock_page(page);
1778
1779 return err;
1780}
1781
1782struct fuse_fill_wb_data {
1783 struct fuse_req *req;
1784 struct fuse_file *ff;
1785 struct inode *inode;
1786 struct page **orig_pages;
1787};
1788
1789static void fuse_writepages_send(struct fuse_fill_wb_data *data)
1790{
1791 struct fuse_req *req = data->req;
1792 struct inode *inode = data->inode;
1793 struct fuse_conn *fc = get_fuse_conn(inode);
1794 struct fuse_inode *fi = get_fuse_inode(inode);
1795 int num_pages = req->num_pages;
1796 int i;
1797
1798 req->ff = fuse_file_get(data->ff);
1799 spin_lock(&fc->lock);
1800 list_add_tail(&req->list, &fi->queued_writes);
1801 fuse_flush_writepages(inode);
1802 spin_unlock(&fc->lock);
1803
1804 for (i = 0; i < num_pages; i++)
1805 end_page_writeback(data->orig_pages[i]);
1806}
1807
1808static bool fuse_writepage_in_flight(struct fuse_req *new_req,
1809 struct page *page)
1810{
1811 struct fuse_conn *fc = get_fuse_conn(new_req->inode);
1812 struct fuse_inode *fi = get_fuse_inode(new_req->inode);
1813 struct fuse_req *tmp;
1814 struct fuse_req *old_req;
1815 bool found = false;
1816 pgoff_t curr_index;
1817
1818 BUG_ON(new_req->num_pages != 0);
1819
1820 spin_lock(&fc->lock);
1821 list_del(&new_req->writepages_entry);
1822 list_for_each_entry(old_req, &fi->writepages, writepages_entry) {
1823 BUG_ON(old_req->inode != new_req->inode);
1824 curr_index = old_req->misc.write.in.offset >> PAGE_CACHE_SHIFT;
1825 if (curr_index <= page->index &&
1826 page->index < curr_index + old_req->num_pages) {
1827 found = true;
1828 break;
1829 }
1830 }
1831 if (!found) {
1832 list_add(&new_req->writepages_entry, &fi->writepages);
1833 goto out_unlock;
1834 }
1835
1836 new_req->num_pages = 1;
1837 for (tmp = old_req; tmp != NULL; tmp = tmp->misc.write.next) {
1838 BUG_ON(tmp->inode != new_req->inode);
1839 curr_index = tmp->misc.write.in.offset >> PAGE_CACHE_SHIFT;
1840 if (tmp->num_pages == 1 &&
1841 curr_index == page->index) {
1842 old_req = tmp;
1843 }
1844 }
1845
1846 if (old_req->num_pages == 1 && (old_req->state == FUSE_REQ_INIT ||
1847 old_req->state == FUSE_REQ_PENDING)) {
1848 struct backing_dev_info *bdi = page->mapping->backing_dev_info;
1849
1850 copy_highpage(old_req->pages[0], page);
1851 spin_unlock(&fc->lock);
1852
1853 dec_bdi_stat(bdi, BDI_WRITEBACK);
1854 dec_zone_page_state(page, NR_WRITEBACK_TEMP);
1855 bdi_writeout_inc(bdi);
1856 fuse_writepage_free(fc, new_req);
1857 fuse_request_free(new_req);
1858 goto out;
1859 } else {
1860 new_req->misc.write.next = old_req->misc.write.next;
1861 old_req->misc.write.next = new_req;
1862 }
1863out_unlock:
1864 spin_unlock(&fc->lock);
1865out:
1866 return found;
1867}
1868
1869static int fuse_writepages_fill(struct page *page,
1870 struct writeback_control *wbc, void *_data)
1871{
1872 struct fuse_fill_wb_data *data = _data;
1873 struct fuse_req *req = data->req;
1874 struct inode *inode = data->inode;
1875 struct fuse_conn *fc = get_fuse_conn(inode);
1876 struct page *tmp_page;
1877 bool is_writeback;
1878 int err;
1879
1880 if (!data->ff) {
1881 err = -EIO;
1882 data->ff = fuse_write_file_get(fc, get_fuse_inode(inode));
1883 if (!data->ff)
1884 goto out_unlock;
1885 }
1886
1887 /*
1888 * Being under writeback is unlikely but possible. For example direct
1889 * read to an mmaped fuse file will set the page dirty twice; once when
1890 * the pages are faulted with get_user_pages(), and then after the read
1891 * completed.
1892 */
1893 is_writeback = fuse_page_is_writeback(inode, page->index);
1894
1895 if (req && req->num_pages &&
1896 (is_writeback || req->num_pages == FUSE_MAX_PAGES_PER_REQ ||
1897 (req->num_pages + 1) * PAGE_CACHE_SIZE > fc->max_write ||
1898 data->orig_pages[req->num_pages - 1]->index + 1 != page->index)) {
1899 fuse_writepages_send(data);
1900 data->req = NULL;
1901 }
1902 err = -ENOMEM;
1903 tmp_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
1904 if (!tmp_page)
1905 goto out_unlock;
1906
1907 /*
1908 * The page must not be redirtied until the writeout is completed
1909 * (i.e. userspace has sent a reply to the write request). Otherwise
1910 * there could be more than one temporary page instance for each real
1911 * page.
1912 *
1913 * This is ensured by holding the page lock in page_mkwrite() while
1914 * checking fuse_page_is_writeback(). We already hold the page lock
1915 * since clear_page_dirty_for_io() and keep it held until we add the
1916 * request to the fi->writepages list and increment req->num_pages.
1917 * After this fuse_page_is_writeback() will indicate that the page is
1918 * under writeback, so we can release the page lock.
1919 */
1920 if (data->req == NULL) {
1921 struct fuse_inode *fi = get_fuse_inode(inode);
1922
1923 err = -ENOMEM;
1924 req = fuse_request_alloc_nofs(FUSE_MAX_PAGES_PER_REQ);
1925 if (!req) {
1926 __free_page(tmp_page);
1927 goto out_unlock;
1928 }
1929
1930 fuse_write_fill(req, data->ff, page_offset(page), 0);
1931 req->misc.write.in.write_flags |= FUSE_WRITE_CACHE;
1932 req->misc.write.next = NULL;
1933 req->in.argpages = 1;
1934 req->background = 1;
1935 req->num_pages = 0;
1936 req->end = fuse_writepage_end;
1937 req->inode = inode;
1938
1939 spin_lock(&fc->lock);
1940 list_add(&req->writepages_entry, &fi->writepages);
1941 spin_unlock(&fc->lock);
1942
1943 data->req = req;
1944 }
1945 set_page_writeback(page);
1946
1947 copy_highpage(tmp_page, page);
1948 req->pages[req->num_pages] = tmp_page;
1949 req->page_descs[req->num_pages].offset = 0;
1950 req->page_descs[req->num_pages].length = PAGE_SIZE;
1951
1952 inc_bdi_stat(page->mapping->backing_dev_info, BDI_WRITEBACK);
1953 inc_zone_page_state(tmp_page, NR_WRITEBACK_TEMP);
1954
1955 err = 0;
1956 if (is_writeback && fuse_writepage_in_flight(req, page)) {
1957 end_page_writeback(page);
1958 data->req = NULL;
1959 goto out_unlock;
1960 }
1961 data->orig_pages[req->num_pages] = page;
1962
1963 /*
1964 * Protected by fc->lock against concurrent access by
1965 * fuse_page_is_writeback().
1966 */
1967 spin_lock(&fc->lock);
1968 req->num_pages++;
1969 spin_unlock(&fc->lock);
1970
1971out_unlock:
1972 unlock_page(page);
1973
1974 return err;
1975}
1976
1977static int fuse_writepages(struct address_space *mapping,
1978 struct writeback_control *wbc)
1979{
1980 struct inode *inode = mapping->host;
1981 struct fuse_fill_wb_data data;
1982 int err;
1983
1984 err = -EIO;
1985 if (is_bad_inode(inode))
1986 goto out;
1987
1988 data.inode = inode;
1989 data.req = NULL;
1990 data.ff = NULL;
1991
1992 err = -ENOMEM;
1993 data.orig_pages = kzalloc(sizeof(struct page *) *
1994 FUSE_MAX_PAGES_PER_REQ,
1995 GFP_NOFS);
1996 if (!data.orig_pages)
1997 goto out;
1998
1999 err = write_cache_pages(mapping, wbc, fuse_writepages_fill, &data);
2000 if (data.req) {
2001 /* Ignore errors if we can write at least one page */
2002 BUG_ON(!data.req->num_pages);
2003 fuse_writepages_send(&data);
2004 err = 0;
2005 }
2006 if (data.ff)
2007 fuse_file_put(data.ff, false);
2008
2009 kfree(data.orig_pages);
2010out:
2011 return err;
2012}
2013
2014/*
2015 * It's worthy to make sure that space is reserved on disk for the write,
2016 * but how to implement it without killing performance need more thinking.
2017 */
2018static int fuse_write_begin(struct file *file, struct address_space *mapping,
2019 loff_t pos, unsigned len, unsigned flags,
2020 struct page **pagep, void **fsdata)
2021{
2022 pgoff_t index = pos >> PAGE_CACHE_SHIFT;
2023 struct fuse_conn *fc = get_fuse_conn(file->f_dentry->d_inode);
2024 struct page *page;
2025 loff_t fsize;
2026 int err = -ENOMEM;
2027
2028 WARN_ON(!fc->writeback_cache);
2029
2030 page = grab_cache_page_write_begin(mapping, index, flags);
2031 if (!page)
2032 goto error;
2033
2034 fuse_wait_on_page_writeback(mapping->host, page->index);
2035
2036 if (PageUptodate(page) || len == PAGE_CACHE_SIZE)
2037 goto success;
2038 /*
2039 * Check if the start this page comes after the end of file, in which
2040 * case the readpage can be optimized away.
2041 */
2042 fsize = i_size_read(mapping->host);
2043 if (fsize <= (pos & PAGE_CACHE_MASK)) {
2044 size_t off = pos & ~PAGE_CACHE_MASK;
2045 if (off)
2046 zero_user_segment(page, 0, off);
2047 goto success;
2048 }
2049 err = fuse_do_readpage(file, page);
2050 if (err)
2051 goto cleanup;
2052success:
2053 *pagep = page;
2054 return 0;
2055
2056cleanup:
2057 unlock_page(page);
2058 page_cache_release(page);
2059error:
2060 return err;
2061}
2062
2063static int fuse_write_end(struct file *file, struct address_space *mapping,
2064 loff_t pos, unsigned len, unsigned copied,
2065 struct page *page, void *fsdata)
2066{
2067 struct inode *inode = page->mapping->host;
2068
2069 if (!PageUptodate(page)) {
2070 /* Zero any unwritten bytes at the end of the page */
2071 size_t endoff = (pos + copied) & ~PAGE_CACHE_MASK;
2072 if (endoff)
2073 zero_user_segment(page, endoff, PAGE_CACHE_SIZE);
2074 SetPageUptodate(page);
2075 }
2076
2077 fuse_write_update_size(inode, pos + copied);
2078 set_page_dirty(page);
2079 unlock_page(page);
2080 page_cache_release(page);
2081
2082 return copied;
2083}
2084
2085static int fuse_launder_page(struct page *page)
2086{
2087 int err = 0;
2088 if (clear_page_dirty_for_io(page)) {
2089 struct inode *inode = page->mapping->host;
2090 err = fuse_writepage_locked(page);
2091 if (!err)
2092 fuse_wait_on_page_writeback(inode, page->index);
2093 }
2094 return err;
2095}
2096
2097/*
2098 * Write back dirty pages now, because there may not be any suitable
2099 * open files later
2100 */
2101static void fuse_vma_close(struct vm_area_struct *vma)
2102{
2103 filemap_write_and_wait(vma->vm_file->f_mapping);
2104}
2105
2106/*
2107 * Wait for writeback against this page to complete before allowing it
2108 * to be marked dirty again, and hence written back again, possibly
2109 * before the previous writepage completed.
2110 *
2111 * Block here, instead of in ->writepage(), so that the userspace fs
2112 * can only block processes actually operating on the filesystem.
2113 *
2114 * Otherwise unprivileged userspace fs would be able to block
2115 * unrelated:
2116 *
2117 * - page migration
2118 * - sync(2)
2119 * - try_to_free_pages() with order > PAGE_ALLOC_COSTLY_ORDER
2120 */
2121static int fuse_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
2122{
2123 struct page *page = vmf->page;
2124 struct inode *inode = file_inode(vma->vm_file);
2125
2126 file_update_time(vma->vm_file);
2127 lock_page(page);
2128 if (page->mapping != inode->i_mapping) {
2129 unlock_page(page);
2130 return VM_FAULT_NOPAGE;
2131 }
2132
2133 fuse_wait_on_page_writeback(inode, page->index);
2134 return VM_FAULT_LOCKED;
2135}
2136
2137static const struct vm_operations_struct fuse_file_vm_ops = {
2138 .close = fuse_vma_close,
2139 .fault = filemap_fault,
2140 .map_pages = filemap_map_pages,
2141 .page_mkwrite = fuse_page_mkwrite,
2142 .remap_pages = generic_file_remap_pages,
2143};
2144
2145static int fuse_file_mmap(struct file *file, struct vm_area_struct *vma)
2146{
2147 if ((vma->vm_flags & VM_SHARED) && (vma->vm_flags & VM_MAYWRITE))
2148 fuse_link_write_file(file);
2149
2150 file_accessed(file);
2151 vma->vm_ops = &fuse_file_vm_ops;
2152 return 0;
2153}
2154
2155static int fuse_direct_mmap(struct file *file, struct vm_area_struct *vma)
2156{
2157 /* Can't provide the coherency needed for MAP_SHARED */
2158 if (vma->vm_flags & VM_MAYSHARE)
2159 return -ENODEV;
2160
2161 invalidate_inode_pages2(file->f_mapping);
2162
2163 return generic_file_mmap(file, vma);
2164}
2165
2166static int convert_fuse_file_lock(const struct fuse_file_lock *ffl,
2167 struct file_lock *fl)
2168{
2169 switch (ffl->type) {
2170 case F_UNLCK:
2171 break;
2172
2173 case F_RDLCK:
2174 case F_WRLCK:
2175 if (ffl->start > OFFSET_MAX || ffl->end > OFFSET_MAX ||
2176 ffl->end < ffl->start)
2177 return -EIO;
2178
2179 fl->fl_start = ffl->start;
2180 fl->fl_end = ffl->end;
2181 fl->fl_pid = ffl->pid;
2182 break;
2183
2184 default:
2185 return -EIO;
2186 }
2187 fl->fl_type = ffl->type;
2188 return 0;
2189}
2190
2191static void fuse_lk_fill(struct fuse_req *req, struct file *file,
2192 const struct file_lock *fl, int opcode, pid_t pid,
2193 int flock)
2194{
2195 struct inode *inode = file_inode(file);
2196 struct fuse_conn *fc = get_fuse_conn(inode);
2197 struct fuse_file *ff = file->private_data;
2198 struct fuse_lk_in *arg = &req->misc.lk_in;
2199
2200 arg->fh = ff->fh;
2201 arg->owner = fuse_lock_owner_id(fc, fl->fl_owner);
2202 arg->lk.start = fl->fl_start;
2203 arg->lk.end = fl->fl_end;
2204 arg->lk.type = fl->fl_type;
2205 arg->lk.pid = pid;
2206 if (flock)
2207 arg->lk_flags |= FUSE_LK_FLOCK;
2208 req->in.h.opcode = opcode;
2209 req->in.h.nodeid = get_node_id(inode);
2210 req->in.numargs = 1;
2211 req->in.args[0].size = sizeof(*arg);
2212 req->in.args[0].value = arg;
2213}
2214
2215static int fuse_getlk(struct file *file, struct file_lock *fl)
2216{
2217 struct inode *inode = file_inode(file);
2218 struct fuse_conn *fc = get_fuse_conn(inode);
2219 struct fuse_req *req;
2220 struct fuse_lk_out outarg;
2221 int err;
2222
2223 req = fuse_get_req_nopages(fc);
2224 if (IS_ERR(req))
2225 return PTR_ERR(req);
2226
2227 fuse_lk_fill(req, file, fl, FUSE_GETLK, 0, 0);
2228 req->out.numargs = 1;
2229 req->out.args[0].size = sizeof(outarg);
2230 req->out.args[0].value = &outarg;
2231 fuse_request_send(fc, req);
2232 err = req->out.h.error;
2233 fuse_put_request(fc, req);
2234 if (!err)
2235 err = convert_fuse_file_lock(&outarg.lk, fl);
2236
2237 return err;
2238}
2239
2240static int fuse_setlk(struct file *file, struct file_lock *fl, int flock)
2241{
2242 struct inode *inode = file_inode(file);
2243 struct fuse_conn *fc = get_fuse_conn(inode);
2244 struct fuse_req *req;
2245 int opcode = (fl->fl_flags & FL_SLEEP) ? FUSE_SETLKW : FUSE_SETLK;
2246 pid_t pid = fl->fl_type != F_UNLCK ? current->tgid : 0;
2247 int err;
2248
2249 if (fl->fl_lmops && fl->fl_lmops->lm_grant) {
2250 /* NLM needs asynchronous locks, which we don't support yet */
2251 return -ENOLCK;
2252 }
2253
2254 /* Unlock on close is handled by the flush method */
2255 if (fl->fl_flags & FL_CLOSE)
2256 return 0;
2257
2258 req = fuse_get_req_nopages(fc);
2259 if (IS_ERR(req))
2260 return PTR_ERR(req);
2261
2262 fuse_lk_fill(req, file, fl, opcode, pid, flock);
2263 fuse_request_send(fc, req);
2264 err = req->out.h.error;
2265 /* locking is restartable */
2266 if (err == -EINTR)
2267 err = -ERESTARTSYS;
2268 fuse_put_request(fc, req);
2269 return err;
2270}
2271
2272static int fuse_file_lock(struct file *file, int cmd, struct file_lock *fl)
2273{
2274 struct inode *inode = file_inode(file);
2275 struct fuse_conn *fc = get_fuse_conn(inode);
2276 int err;
2277
2278 if (cmd == F_CANCELLK) {
2279 err = 0;
2280 } else if (cmd == F_GETLK) {
2281 if (fc->no_lock) {
2282 posix_test_lock(file, fl);
2283 err = 0;
2284 } else
2285 err = fuse_getlk(file, fl);
2286 } else {
2287 if (fc->no_lock)
2288 err = posix_lock_file(file, fl, NULL);
2289 else
2290 err = fuse_setlk(file, fl, 0);
2291 }
2292 return err;
2293}
2294
2295static int fuse_file_flock(struct file *file, int cmd, struct file_lock *fl)
2296{
2297 struct inode *inode = file_inode(file);
2298 struct fuse_conn *fc = get_fuse_conn(inode);
2299 int err;
2300
2301 if (fc->no_flock) {
2302 err = flock_lock_file_wait(file, fl);
2303 } else {
2304 struct fuse_file *ff = file->private_data;
2305
2306 /* emulate flock with POSIX locks */
2307 fl->fl_owner = (fl_owner_t) file;
2308 ff->flock = true;
2309 err = fuse_setlk(file, fl, 1);
2310 }
2311
2312 return err;
2313}
2314
2315static sector_t fuse_bmap(struct address_space *mapping, sector_t block)
2316{
2317 struct inode *inode = mapping->host;
2318 struct fuse_conn *fc = get_fuse_conn(inode);
2319 struct fuse_req *req;
2320 struct fuse_bmap_in inarg;
2321 struct fuse_bmap_out outarg;
2322 int err;
2323
2324 if (!inode->i_sb->s_bdev || fc->no_bmap)
2325 return 0;
2326
2327 req = fuse_get_req_nopages(fc);
2328 if (IS_ERR(req))
2329 return 0;
2330
2331 memset(&inarg, 0, sizeof(inarg));
2332 inarg.block = block;
2333 inarg.blocksize = inode->i_sb->s_blocksize;
2334 req->in.h.opcode = FUSE_BMAP;
2335 req->in.h.nodeid = get_node_id(inode);
2336 req->in.numargs = 1;
2337 req->in.args[0].size = sizeof(inarg);
2338 req->in.args[0].value = &inarg;
2339 req->out.numargs = 1;
2340 req->out.args[0].size = sizeof(outarg);
2341 req->out.args[0].value = &outarg;
2342 fuse_request_send(fc, req);
2343 err = req->out.h.error;
2344 fuse_put_request(fc, req);
2345 if (err == -ENOSYS)
2346 fc->no_bmap = 1;
2347
2348 return err ? 0 : outarg.block;
2349}
2350
2351static loff_t fuse_file_llseek(struct file *file, loff_t offset, int whence)
2352{
2353 loff_t retval;
2354 struct inode *inode = file_inode(file);
2355
2356 /* No i_mutex protection necessary for SEEK_CUR and SEEK_SET */
2357 if (whence == SEEK_CUR || whence == SEEK_SET)
2358 return generic_file_llseek(file, offset, whence);
2359
2360 mutex_lock(&inode->i_mutex);
2361 retval = fuse_update_attributes(inode, NULL, file, NULL);
2362 if (!retval)
2363 retval = generic_file_llseek(file, offset, whence);
2364 mutex_unlock(&inode->i_mutex);
2365
2366 return retval;
2367}
2368
2369static int fuse_ioctl_copy_user(struct page **pages, struct iovec *iov,
2370 unsigned int nr_segs, size_t bytes, bool to_user)
2371{
2372 struct iov_iter ii;
2373 int page_idx = 0;
2374
2375 if (!bytes)
2376 return 0;
2377
2378 iov_iter_init(&ii, iov, nr_segs, bytes, 0);
2379
2380 while (iov_iter_count(&ii)) {
2381 struct page *page = pages[page_idx++];
2382 size_t todo = min_t(size_t, PAGE_SIZE, iov_iter_count(&ii));
2383 void *kaddr;
2384
2385 kaddr = kmap(page);
2386
2387 while (todo) {
2388 char __user *uaddr = ii.iov->iov_base + ii.iov_offset;
2389 size_t iov_len = ii.iov->iov_len - ii.iov_offset;
2390 size_t copy = min(todo, iov_len);
2391 size_t left;
2392
2393 if (!to_user)
2394 left = copy_from_user(kaddr, uaddr, copy);
2395 else
2396 left = copy_to_user(uaddr, kaddr, copy);
2397
2398 if (unlikely(left))
2399 return -EFAULT;
2400
2401 iov_iter_advance(&ii, copy);
2402 todo -= copy;
2403 kaddr += copy;
2404 }
2405
2406 kunmap(page);
2407 }
2408
2409 return 0;
2410}
2411
2412/*
2413 * CUSE servers compiled on 32bit broke on 64bit kernels because the
2414 * ABI was defined to be 'struct iovec' which is different on 32bit
2415 * and 64bit. Fortunately we can determine which structure the server
2416 * used from the size of the reply.
2417 */
2418static int fuse_copy_ioctl_iovec_old(struct iovec *dst, void *src,
2419 size_t transferred, unsigned count,
2420 bool is_compat)
2421{
2422#ifdef CONFIG_COMPAT
2423 if (count * sizeof(struct compat_iovec) == transferred) {
2424 struct compat_iovec *ciov = src;
2425 unsigned i;
2426
2427 /*
2428 * With this interface a 32bit server cannot support
2429 * non-compat (i.e. ones coming from 64bit apps) ioctl
2430 * requests
2431 */
2432 if (!is_compat)
2433 return -EINVAL;
2434
2435 for (i = 0; i < count; i++) {
2436 dst[i].iov_base = compat_ptr(ciov[i].iov_base);
2437 dst[i].iov_len = ciov[i].iov_len;
2438 }
2439 return 0;
2440 }
2441#endif
2442
2443 if (count * sizeof(struct iovec) != transferred)
2444 return -EIO;
2445
2446 memcpy(dst, src, transferred);
2447 return 0;
2448}
2449
2450/* Make sure iov_length() won't overflow */
2451static int fuse_verify_ioctl_iov(struct iovec *iov, size_t count)
2452{
2453 size_t n;
2454 u32 max = FUSE_MAX_PAGES_PER_REQ << PAGE_SHIFT;
2455
2456 for (n = 0; n < count; n++, iov++) {
2457 if (iov->iov_len > (size_t) max)
2458 return -ENOMEM;
2459 max -= iov->iov_len;
2460 }
2461 return 0;
2462}
2463
2464static int fuse_copy_ioctl_iovec(struct fuse_conn *fc, struct iovec *dst,
2465 void *src, size_t transferred, unsigned count,
2466 bool is_compat)
2467{
2468 unsigned i;
2469 struct fuse_ioctl_iovec *fiov = src;
2470
2471 if (fc->minor < 16) {
2472 return fuse_copy_ioctl_iovec_old(dst, src, transferred,
2473 count, is_compat);
2474 }
2475
2476 if (count * sizeof(struct fuse_ioctl_iovec) != transferred)
2477 return -EIO;
2478
2479 for (i = 0; i < count; i++) {
2480 /* Did the server supply an inappropriate value? */
2481 if (fiov[i].base != (unsigned long) fiov[i].base ||
2482 fiov[i].len != (unsigned long) fiov[i].len)
2483 return -EIO;
2484
2485 dst[i].iov_base = (void __user *) (unsigned long) fiov[i].base;
2486 dst[i].iov_len = (size_t) fiov[i].len;
2487
2488#ifdef CONFIG_COMPAT
2489 if (is_compat &&
2490 (ptr_to_compat(dst[i].iov_base) != fiov[i].base ||
2491 (compat_size_t) dst[i].iov_len != fiov[i].len))
2492 return -EIO;
2493#endif
2494 }
2495
2496 return 0;
2497}
2498
2499
2500/*
2501 * For ioctls, there is no generic way to determine how much memory
2502 * needs to be read and/or written. Furthermore, ioctls are allowed
2503 * to dereference the passed pointer, so the parameter requires deep
2504 * copying but FUSE has no idea whatsoever about what to copy in or
2505 * out.
2506 *
2507 * This is solved by allowing FUSE server to retry ioctl with
2508 * necessary in/out iovecs. Let's assume the ioctl implementation
2509 * needs to read in the following structure.
2510 *
2511 * struct a {
2512 * char *buf;
2513 * size_t buflen;
2514 * }
2515 *
2516 * On the first callout to FUSE server, inarg->in_size and
2517 * inarg->out_size will be NULL; then, the server completes the ioctl
2518 * with FUSE_IOCTL_RETRY set in out->flags, out->in_iovs set to 1 and
2519 * the actual iov array to
2520 *
2521 * { { .iov_base = inarg.arg, .iov_len = sizeof(struct a) } }
2522 *
2523 * which tells FUSE to copy in the requested area and retry the ioctl.
2524 * On the second round, the server has access to the structure and
2525 * from that it can tell what to look for next, so on the invocation,
2526 * it sets FUSE_IOCTL_RETRY, out->in_iovs to 2 and iov array to
2527 *
2528 * { { .iov_base = inarg.arg, .iov_len = sizeof(struct a) },
2529 * { .iov_base = a.buf, .iov_len = a.buflen } }
2530 *
2531 * FUSE will copy both struct a and the pointed buffer from the
2532 * process doing the ioctl and retry ioctl with both struct a and the
2533 * buffer.
2534 *
2535 * This time, FUSE server has everything it needs and completes ioctl
2536 * without FUSE_IOCTL_RETRY which finishes the ioctl call.
2537 *
2538 * Copying data out works the same way.
2539 *
2540 * Note that if FUSE_IOCTL_UNRESTRICTED is clear, the kernel
2541 * automatically initializes in and out iovs by decoding @cmd with
2542 * _IOC_* macros and the server is not allowed to request RETRY. This
2543 * limits ioctl data transfers to well-formed ioctls and is the forced
2544 * behavior for all FUSE servers.
2545 */
2546long fuse_do_ioctl(struct file *file, unsigned int cmd, unsigned long arg,
2547 unsigned int flags)
2548{
2549 struct fuse_file *ff = file->private_data;
2550 struct fuse_conn *fc = ff->fc;
2551 struct fuse_ioctl_in inarg = {
2552 .fh = ff->fh,
2553 .cmd = cmd,
2554 .arg = arg,
2555 .flags = flags
2556 };
2557 struct fuse_ioctl_out outarg;
2558 struct fuse_req *req = NULL;
2559 struct page **pages = NULL;
2560 struct iovec *iov_page = NULL;
2561 struct iovec *in_iov = NULL, *out_iov = NULL;
2562 unsigned int in_iovs = 0, out_iovs = 0, num_pages = 0, max_pages;
2563 size_t in_size, out_size, transferred;
2564 int err;
2565
2566#if BITS_PER_LONG == 32
2567 inarg.flags |= FUSE_IOCTL_32BIT;
2568#else
2569 if (flags & FUSE_IOCTL_COMPAT)
2570 inarg.flags |= FUSE_IOCTL_32BIT;
2571#endif
2572
2573 /* assume all the iovs returned by client always fits in a page */
2574 BUILD_BUG_ON(sizeof(struct fuse_ioctl_iovec) * FUSE_IOCTL_MAX_IOV > PAGE_SIZE);
2575
2576 err = -ENOMEM;
2577 pages = kcalloc(FUSE_MAX_PAGES_PER_REQ, sizeof(pages[0]), GFP_KERNEL);
2578 iov_page = (struct iovec *) __get_free_page(GFP_KERNEL);
2579 if (!pages || !iov_page)
2580 goto out;
2581
2582 /*
2583 * If restricted, initialize IO parameters as encoded in @cmd.
2584 * RETRY from server is not allowed.
2585 */
2586 if (!(flags & FUSE_IOCTL_UNRESTRICTED)) {
2587 struct iovec *iov = iov_page;
2588
2589 iov->iov_base = (void __user *)arg;
2590 iov->iov_len = _IOC_SIZE(cmd);
2591
2592 if (_IOC_DIR(cmd) & _IOC_WRITE) {
2593 in_iov = iov;
2594 in_iovs = 1;
2595 }
2596
2597 if (_IOC_DIR(cmd) & _IOC_READ) {
2598 out_iov = iov;
2599 out_iovs = 1;
2600 }
2601 }
2602
2603 retry:
2604 inarg.in_size = in_size = iov_length(in_iov, in_iovs);
2605 inarg.out_size = out_size = iov_length(out_iov, out_iovs);
2606
2607 /*
2608 * Out data can be used either for actual out data or iovs,
2609 * make sure there always is at least one page.
2610 */
2611 out_size = max_t(size_t, out_size, PAGE_SIZE);
2612 max_pages = DIV_ROUND_UP(max(in_size, out_size), PAGE_SIZE);
2613
2614 /* make sure there are enough buffer pages and init request with them */
2615 err = -ENOMEM;
2616 if (max_pages > FUSE_MAX_PAGES_PER_REQ)
2617 goto out;
2618 while (num_pages < max_pages) {
2619 pages[num_pages] = alloc_page(GFP_KERNEL | __GFP_HIGHMEM);
2620 if (!pages[num_pages])
2621 goto out;
2622 num_pages++;
2623 }
2624
2625 req = fuse_get_req(fc, num_pages);
2626 if (IS_ERR(req)) {
2627 err = PTR_ERR(req);
2628 req = NULL;
2629 goto out;
2630 }
2631 memcpy(req->pages, pages, sizeof(req->pages[0]) * num_pages);
2632 req->num_pages = num_pages;
2633 fuse_page_descs_length_init(req, 0, req->num_pages);
2634
2635 /* okay, let's send it to the client */
2636 req->in.h.opcode = FUSE_IOCTL;
2637 req->in.h.nodeid = ff->nodeid;
2638 req->in.numargs = 1;
2639 req->in.args[0].size = sizeof(inarg);
2640 req->in.args[0].value = &inarg;
2641 if (in_size) {
2642 req->in.numargs++;
2643 req->in.args[1].size = in_size;
2644 req->in.argpages = 1;
2645
2646 err = fuse_ioctl_copy_user(pages, in_iov, in_iovs, in_size,
2647 false);
2648 if (err)
2649 goto out;
2650 }
2651
2652 req->out.numargs = 2;
2653 req->out.args[0].size = sizeof(outarg);
2654 req->out.args[0].value = &outarg;
2655 req->out.args[1].size = out_size;
2656 req->out.argpages = 1;
2657 req->out.argvar = 1;
2658
2659 fuse_request_send(fc, req);
2660 err = req->out.h.error;
2661 transferred = req->out.args[1].size;
2662 fuse_put_request(fc, req);
2663 req = NULL;
2664 if (err)
2665 goto out;
2666
2667 /* did it ask for retry? */
2668 if (outarg.flags & FUSE_IOCTL_RETRY) {
2669 void *vaddr;
2670
2671 /* no retry if in restricted mode */
2672 err = -EIO;
2673 if (!(flags & FUSE_IOCTL_UNRESTRICTED))
2674 goto out;
2675
2676 in_iovs = outarg.in_iovs;
2677 out_iovs = outarg.out_iovs;
2678
2679 /*
2680 * Make sure things are in boundary, separate checks
2681 * are to protect against overflow.
2682 */
2683 err = -ENOMEM;
2684 if (in_iovs > FUSE_IOCTL_MAX_IOV ||
2685 out_iovs > FUSE_IOCTL_MAX_IOV ||
2686 in_iovs + out_iovs > FUSE_IOCTL_MAX_IOV)
2687 goto out;
2688
2689 vaddr = kmap_atomic(pages[0]);
2690 err = fuse_copy_ioctl_iovec(fc, iov_page, vaddr,
2691 transferred, in_iovs + out_iovs,
2692 (flags & FUSE_IOCTL_COMPAT) != 0);
2693 kunmap_atomic(vaddr);
2694 if (err)
2695 goto out;
2696
2697 in_iov = iov_page;
2698 out_iov = in_iov + in_iovs;
2699
2700 err = fuse_verify_ioctl_iov(in_iov, in_iovs);
2701 if (err)
2702 goto out;
2703
2704 err = fuse_verify_ioctl_iov(out_iov, out_iovs);
2705 if (err)
2706 goto out;
2707
2708 goto retry;
2709 }
2710
2711 err = -EIO;
2712 if (transferred > inarg.out_size)
2713 goto out;
2714
2715 err = fuse_ioctl_copy_user(pages, out_iov, out_iovs, transferred, true);
2716 out:
2717 if (req)
2718 fuse_put_request(fc, req);
2719 free_page((unsigned long) iov_page);
2720 while (num_pages)
2721 __free_page(pages[--num_pages]);
2722 kfree(pages);
2723
2724 return err ? err : outarg.result;
2725}
2726EXPORT_SYMBOL_GPL(fuse_do_ioctl);
2727
2728long fuse_ioctl_common(struct file *file, unsigned int cmd,
2729 unsigned long arg, unsigned int flags)
2730{
2731 struct inode *inode = file_inode(file);
2732 struct fuse_conn *fc = get_fuse_conn(inode);
2733
2734 if (!fuse_allow_current_process(fc))
2735 return -EACCES;
2736
2737 if (is_bad_inode(inode))
2738 return -EIO;
2739
2740 return fuse_do_ioctl(file, cmd, arg, flags);
2741}
2742
2743static long fuse_file_ioctl(struct file *file, unsigned int cmd,
2744 unsigned long arg)
2745{
2746 return fuse_ioctl_common(file, cmd, arg, 0);
2747}
2748
2749static long fuse_file_compat_ioctl(struct file *file, unsigned int cmd,
2750 unsigned long arg)
2751{
2752 return fuse_ioctl_common(file, cmd, arg, FUSE_IOCTL_COMPAT);
2753}
2754
2755/*
2756 * All files which have been polled are linked to RB tree
2757 * fuse_conn->polled_files which is indexed by kh. Walk the tree and
2758 * find the matching one.
2759 */
2760static struct rb_node **fuse_find_polled_node(struct fuse_conn *fc, u64 kh,
2761 struct rb_node **parent_out)
2762{
2763 struct rb_node **link = &fc->polled_files.rb_node;
2764 struct rb_node *last = NULL;
2765
2766 while (*link) {
2767 struct fuse_file *ff;
2768
2769 last = *link;
2770 ff = rb_entry(last, struct fuse_file, polled_node);
2771
2772 if (kh < ff->kh)
2773 link = &last->rb_left;
2774 else if (kh > ff->kh)
2775 link = &last->rb_right;
2776 else
2777 return link;
2778 }
2779
2780 if (parent_out)
2781 *parent_out = last;
2782 return link;
2783}
2784
2785/*
2786 * The file is about to be polled. Make sure it's on the polled_files
2787 * RB tree. Note that files once added to the polled_files tree are
2788 * not removed before the file is released. This is because a file
2789 * polled once is likely to be polled again.
2790 */
2791static void fuse_register_polled_file(struct fuse_conn *fc,
2792 struct fuse_file *ff)
2793{
2794 spin_lock(&fc->lock);
2795 if (RB_EMPTY_NODE(&ff->polled_node)) {
2796 struct rb_node **link, *uninitialized_var(parent);
2797
2798 link = fuse_find_polled_node(fc, ff->kh, &parent);
2799 BUG_ON(*link);
2800 rb_link_node(&ff->polled_node, parent, link);
2801 rb_insert_color(&ff->polled_node, &fc->polled_files);
2802 }
2803 spin_unlock(&fc->lock);
2804}
2805
2806unsigned fuse_file_poll(struct file *file, poll_table *wait)
2807{
2808 struct fuse_file *ff = file->private_data;
2809 struct fuse_conn *fc = ff->fc;
2810 struct fuse_poll_in inarg = { .fh = ff->fh, .kh = ff->kh };
2811 struct fuse_poll_out outarg;
2812 struct fuse_req *req;
2813 int err;
2814
2815 if (fc->no_poll)
2816 return DEFAULT_POLLMASK;
2817
2818 poll_wait(file, &ff->poll_wait, wait);
2819 inarg.events = (__u32)poll_requested_events(wait);
2820
2821 /*
2822 * Ask for notification iff there's someone waiting for it.
2823 * The client may ignore the flag and always notify.
2824 */
2825 if (waitqueue_active(&ff->poll_wait)) {
2826 inarg.flags |= FUSE_POLL_SCHEDULE_NOTIFY;
2827 fuse_register_polled_file(fc, ff);
2828 }
2829
2830 req = fuse_get_req_nopages(fc);
2831 if (IS_ERR(req))
2832 return POLLERR;
2833
2834 req->in.h.opcode = FUSE_POLL;
2835 req->in.h.nodeid = ff->nodeid;
2836 req->in.numargs = 1;
2837 req->in.args[0].size = sizeof(inarg);
2838 req->in.args[0].value = &inarg;
2839 req->out.numargs = 1;
2840 req->out.args[0].size = sizeof(outarg);
2841 req->out.args[0].value = &outarg;
2842 fuse_request_send(fc, req);
2843 err = req->out.h.error;
2844 fuse_put_request(fc, req);
2845
2846 if (!err)
2847 return outarg.revents;
2848 if (err == -ENOSYS) {
2849 fc->no_poll = 1;
2850 return DEFAULT_POLLMASK;
2851 }
2852 return POLLERR;
2853}
2854EXPORT_SYMBOL_GPL(fuse_file_poll);
2855
2856/*
2857 * This is called from fuse_handle_notify() on FUSE_NOTIFY_POLL and
2858 * wakes up the poll waiters.
2859 */
2860int fuse_notify_poll_wakeup(struct fuse_conn *fc,
2861 struct fuse_notify_poll_wakeup_out *outarg)
2862{
2863 u64 kh = outarg->kh;
2864 struct rb_node **link;
2865
2866 spin_lock(&fc->lock);
2867
2868 link = fuse_find_polled_node(fc, kh, NULL);
2869 if (*link) {
2870 struct fuse_file *ff;
2871
2872 ff = rb_entry(*link, struct fuse_file, polled_node);
2873 wake_up_interruptible_sync(&ff->poll_wait);
2874 }
2875
2876 spin_unlock(&fc->lock);
2877 return 0;
2878}
2879
2880static void fuse_do_truncate(struct file *file)
2881{
2882 struct inode *inode = file->f_mapping->host;
2883 struct iattr attr;
2884
2885 attr.ia_valid = ATTR_SIZE;
2886 attr.ia_size = i_size_read(inode);
2887
2888 attr.ia_file = file;
2889 attr.ia_valid |= ATTR_FILE;
2890
2891 fuse_do_setattr(inode, &attr, file);
2892}
2893
2894static inline loff_t fuse_round_up(loff_t off)
2895{
2896 return round_up(off, FUSE_MAX_PAGES_PER_REQ << PAGE_SHIFT);
2897}
2898
2899static ssize_t
2900fuse_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov,
2901 loff_t offset, unsigned long nr_segs)
2902{
2903 ssize_t ret = 0;
2904 struct file *file = iocb->ki_filp;
2905 struct fuse_file *ff = file->private_data;
2906 bool async_dio = ff->fc->async_dio;
2907 loff_t pos = 0;
2908 struct inode *inode;
2909 loff_t i_size;
2910 size_t count = iov_length(iov, nr_segs);
2911 struct fuse_io_priv *io;
2912
2913 pos = offset;
2914 inode = file->f_mapping->host;
2915 i_size = i_size_read(inode);
2916
2917 if ((rw == READ) && (offset > i_size))
2918 return 0;
2919
2920 /* optimization for short read */
2921 if (async_dio && rw != WRITE && offset + count > i_size) {
2922 if (offset >= i_size)
2923 return 0;
2924 count = min_t(loff_t, count, fuse_round_up(i_size - offset));
2925 }
2926
2927 io = kmalloc(sizeof(struct fuse_io_priv), GFP_KERNEL);
2928 if (!io)
2929 return -ENOMEM;
2930 spin_lock_init(&io->lock);
2931 io->reqs = 1;
2932 io->bytes = -1;
2933 io->size = 0;
2934 io->offset = offset;
2935 io->write = (rw == WRITE);
2936 io->err = 0;
2937 io->file = file;
2938 /*
2939 * By default, we want to optimize all I/Os with async request
2940 * submission to the client filesystem if supported.
2941 */
2942 io->async = async_dio;
2943 io->iocb = iocb;
2944
2945 /*
2946 * We cannot asynchronously extend the size of a file. We have no method
2947 * to wait on real async I/O requests, so we must submit this request
2948 * synchronously.
2949 */
2950 if (!is_sync_kiocb(iocb) && (offset + count > i_size) && rw == WRITE)
2951 io->async = false;
2952
2953 if (rw == WRITE)
2954 ret = __fuse_direct_write(io, iov, nr_segs, &pos);
2955 else
2956 ret = __fuse_direct_read(io, iov, nr_segs, &pos, count);
2957
2958 if (io->async) {
2959 fuse_aio_complete(io, ret < 0 ? ret : 0, -1);
2960
2961 /* we have a non-extending, async request, so return */
2962 if (!is_sync_kiocb(iocb))
2963 return -EIOCBQUEUED;
2964
2965 ret = wait_on_sync_kiocb(iocb);
2966 } else {
2967 kfree(io);
2968 }
2969
2970 if (rw == WRITE) {
2971 if (ret > 0)
2972 fuse_write_update_size(inode, pos);
2973 else if (ret < 0 && offset + count > i_size)
2974 fuse_do_truncate(file);
2975 }
2976
2977 return ret;
2978}
2979
2980static long fuse_file_fallocate(struct file *file, int mode, loff_t offset,
2981 loff_t length)
2982{
2983 struct fuse_file *ff = file->private_data;
2984 struct inode *inode = file->f_inode;
2985 struct fuse_inode *fi = get_fuse_inode(inode);
2986 struct fuse_conn *fc = ff->fc;
2987 struct fuse_req *req;
2988 struct fuse_fallocate_in inarg = {
2989 .fh = ff->fh,
2990 .offset = offset,
2991 .length = length,
2992 .mode = mode
2993 };
2994 int err;
2995 bool lock_inode = !(mode & FALLOC_FL_KEEP_SIZE) ||
2996 (mode & FALLOC_FL_PUNCH_HOLE);
2997
2998 if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE))
2999 return -EOPNOTSUPP;
3000
3001 if (fc->no_fallocate)
3002 return -EOPNOTSUPP;
3003
3004 if (lock_inode) {
3005 mutex_lock(&inode->i_mutex);
3006 if (mode & FALLOC_FL_PUNCH_HOLE) {
3007 loff_t endbyte = offset + length - 1;
3008 err = filemap_write_and_wait_range(inode->i_mapping,
3009 offset, endbyte);
3010 if (err)
3011 goto out;
3012
3013 fuse_sync_writes(inode);
3014 }
3015 }
3016
3017 if (!(mode & FALLOC_FL_KEEP_SIZE))
3018 set_bit(FUSE_I_SIZE_UNSTABLE, &fi->state);
3019
3020 req = fuse_get_req_nopages(fc);
3021 if (IS_ERR(req)) {
3022 err = PTR_ERR(req);
3023 goto out;
3024 }
3025
3026 req->in.h.opcode = FUSE_FALLOCATE;
3027 req->in.h.nodeid = ff->nodeid;
3028 req->in.numargs = 1;
3029 req->in.args[0].size = sizeof(inarg);
3030 req->in.args[0].value = &inarg;
3031 fuse_request_send(fc, req);
3032 err = req->out.h.error;
3033 if (err == -ENOSYS) {
3034 fc->no_fallocate = 1;
3035 err = -EOPNOTSUPP;
3036 }
3037 fuse_put_request(fc, req);
3038
3039 if (err)
3040 goto out;
3041
3042 /* we could have extended the file */
3043 if (!(mode & FALLOC_FL_KEEP_SIZE)) {
3044 bool changed = fuse_write_update_size(inode, offset + length);
3045
3046 if (changed && fc->writeback_cache)
3047 file_update_time(file);
3048 }
3049
3050 if (mode & FALLOC_FL_PUNCH_HOLE)
3051 truncate_pagecache_range(inode, offset, offset + length - 1);
3052
3053 fuse_invalidate_attr(inode);
3054
3055out:
3056 if (!(mode & FALLOC_FL_KEEP_SIZE))
3057 clear_bit(FUSE_I_SIZE_UNSTABLE, &fi->state);
3058
3059 if (lock_inode)
3060 mutex_unlock(&inode->i_mutex);
3061
3062 return err;
3063}
3064
3065static const struct file_operations fuse_file_operations = {
3066 .llseek = fuse_file_llseek,
3067 .read = do_sync_read,
3068 .aio_read = fuse_file_aio_read,
3069 .write = do_sync_write,
3070 .aio_write = fuse_file_aio_write,
3071 .mmap = fuse_file_mmap,
3072 .open = fuse_open,
3073 .flush = fuse_flush,
3074 .release = fuse_release,
3075 .fsync = fuse_fsync,
3076 .lock = fuse_file_lock,
3077 .flock = fuse_file_flock,
3078 .splice_read = generic_file_splice_read,
3079 .unlocked_ioctl = fuse_file_ioctl,
3080 .compat_ioctl = fuse_file_compat_ioctl,
3081 .poll = fuse_file_poll,
3082 .fallocate = fuse_file_fallocate,
3083};
3084
3085static const struct file_operations fuse_direct_io_file_operations = {
3086 .llseek = fuse_file_llseek,
3087 .read = fuse_direct_read,
3088 .write = fuse_direct_write,
3089 .mmap = fuse_direct_mmap,
3090 .open = fuse_open,
3091 .flush = fuse_flush,
3092 .release = fuse_release,
3093 .fsync = fuse_fsync,
3094 .lock = fuse_file_lock,
3095 .flock = fuse_file_flock,
3096 .unlocked_ioctl = fuse_file_ioctl,
3097 .compat_ioctl = fuse_file_compat_ioctl,
3098 .poll = fuse_file_poll,
3099 .fallocate = fuse_file_fallocate,
3100 /* no splice_read */
3101};
3102
3103static const struct address_space_operations fuse_file_aops = {
3104 .readpage = fuse_readpage,
3105 .writepage = fuse_writepage,
3106 .writepages = fuse_writepages,
3107 .launder_page = fuse_launder_page,
3108 .readpages = fuse_readpages,
3109 .set_page_dirty = __set_page_dirty_nobuffers,
3110 .bmap = fuse_bmap,
3111 .direct_IO = fuse_direct_IO,
3112 .write_begin = fuse_write_begin,
3113 .write_end = fuse_write_end,
3114};
3115
3116void fuse_init_file_inode(struct inode *inode)
3117{
3118 inode->i_fop = &fuse_file_operations;
3119 inode->i_data.a_ops = &fuse_file_aops;
3120}