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/compat.h>
18 #include <linux/swap.h>
19 #include <linux/falloc.h>
20 #include <linux/uio.h>
21
22 static int fuse_send_open(struct fuse_conn *fc, u64 nodeid, struct file *file,
23 int opcode, struct fuse_open_out *outargp)
24 {
25 struct fuse_open_in inarg;
26 FUSE_ARGS(args);
27
28 memset(&inarg, 0, sizeof(inarg));
29 inarg.flags = file->f_flags & ~(O_CREAT | O_EXCL | O_NOCTTY);
30 if (!fc->atomic_o_trunc)
31 inarg.flags &= ~O_TRUNC;
32 args.in.h.opcode = opcode;
33 args.in.h.nodeid = nodeid;
34 args.in.numargs = 1;
35 args.in.args[0].size = sizeof(inarg);
36 args.in.args[0].value = &inarg;
37 args.out.numargs = 1;
38 args.out.args[0].size = sizeof(*outargp);
39 args.out.args[0].value = outargp;
40
41 return fuse_simple_request(fc, &args);
42 }
43
44 struct fuse_file *fuse_file_alloc(struct fuse_conn *fc)
45 {
46 struct fuse_file *ff;
47
48 ff = kzalloc(sizeof(struct fuse_file), GFP_KERNEL);
49 if (unlikely(!ff))
50 return NULL;
51
52 ff->fc = fc;
53 ff->reserved_req = fuse_request_alloc(0);
54 if (unlikely(!ff->reserved_req)) {
55 kfree(ff);
56 return NULL;
57 }
58
59 INIT_LIST_HEAD(&ff->write_entry);
60 mutex_init(&ff->readdir.lock);
61 refcount_set(&ff->count, 1);
62 RB_CLEAR_NODE(&ff->polled_node);
63 init_waitqueue_head(&ff->poll_wait);
64
65 ff->kh = atomic64_inc_return(&fc->khctr);
66
67 return ff;
68 }
69
70 void fuse_file_free(struct fuse_file *ff)
71 {
72 fuse_request_free(ff->reserved_req);
73 mutex_destroy(&ff->readdir.lock);
74 kfree(ff);
75 }
76
77 static struct fuse_file *fuse_file_get(struct fuse_file *ff)
78 {
79 refcount_inc(&ff->count);
80 return ff;
81 }
82
83 static void fuse_release_end(struct fuse_conn *fc, struct fuse_req *req)
84 {
85 iput(req->misc.release.inode);
86 }
87
88 static void fuse_file_put(struct fuse_file *ff, bool sync, bool isdir)
89 {
90 if (refcount_dec_and_test(&ff->count)) {
91 struct fuse_req *req = ff->reserved_req;
92
93 if (isdir ? ff->fc->no_opendir : ff->fc->no_open) {
94 /*
95 * Drop the release request when client does not
96 * implement 'open'
97 */
98 __clear_bit(FR_BACKGROUND, &req->flags);
99 iput(req->misc.release.inode);
100 fuse_put_request(ff->fc, req);
101 } else if (sync) {
102 __set_bit(FR_FORCE, &req->flags);
103 __clear_bit(FR_BACKGROUND, &req->flags);
104 fuse_request_send(ff->fc, req);
105 iput(req->misc.release.inode);
106 fuse_put_request(ff->fc, req);
107 } else {
108 req->end = fuse_release_end;
109 __set_bit(FR_BACKGROUND, &req->flags);
110 fuse_request_send_background(ff->fc, req);
111 }
112 kfree(ff);
113 }
114 }
115
116 int fuse_do_open(struct fuse_conn *fc, u64 nodeid, struct file *file,
117 bool isdir)
118 {
119 struct fuse_file *ff;
120 int opcode = isdir ? FUSE_OPENDIR : FUSE_OPEN;
121
122 ff = fuse_file_alloc(fc);
123 if (!ff)
124 return -ENOMEM;
125
126 ff->fh = 0;
127 /* Default for no-open */
128 ff->open_flags = FOPEN_KEEP_CACHE | (isdir ? FOPEN_CACHE_DIR : 0);
129 if (isdir ? !fc->no_opendir : !fc->no_open) {
130 struct fuse_open_out outarg;
131 int err;
132
133 err = fuse_send_open(fc, nodeid, file, opcode, &outarg);
134 if (!err) {
135 ff->fh = outarg.fh;
136 ff->open_flags = outarg.open_flags;
137
138 } else if (err != -ENOSYS) {
139 fuse_file_free(ff);
140 return err;
141 } else {
142 if (isdir)
143 fc->no_opendir = 1;
144 else
145 fc->no_open = 1;
146 }
147 }
148
149 if (isdir)
150 ff->open_flags &= ~FOPEN_DIRECT_IO;
151
152 ff->nodeid = nodeid;
153 file->private_data = ff;
154
155 return 0;
156 }
157 EXPORT_SYMBOL_GPL(fuse_do_open);
158
159 static void fuse_link_write_file(struct file *file)
160 {
161 struct inode *inode = file_inode(file);
162 struct fuse_inode *fi = get_fuse_inode(inode);
163 struct fuse_file *ff = file->private_data;
164 /*
165 * file may be written through mmap, so chain it onto the
166 * inodes's write_file list
167 */
168 spin_lock(&fi->lock);
169 if (list_empty(&ff->write_entry))
170 list_add(&ff->write_entry, &fi->write_files);
171 spin_unlock(&fi->lock);
172 }
173
174 void fuse_finish_open(struct inode *inode, struct file *file)
175 {
176 struct fuse_file *ff = file->private_data;
177 struct fuse_conn *fc = get_fuse_conn(inode);
178
179 if (!(ff->open_flags & FOPEN_KEEP_CACHE))
180 invalidate_inode_pages2(inode->i_mapping);
181 if (ff->open_flags & FOPEN_STREAM)
182 stream_open(inode, file);
183 else if (ff->open_flags & FOPEN_NONSEEKABLE)
184 nonseekable_open(inode, file);
185 if (fc->atomic_o_trunc && (file->f_flags & O_TRUNC)) {
186 struct fuse_inode *fi = get_fuse_inode(inode);
187
188 spin_lock(&fi->lock);
189 fi->attr_version = atomic64_inc_return(&fc->attr_version);
190 i_size_write(inode, 0);
191 spin_unlock(&fi->lock);
192 fuse_invalidate_attr(inode);
193 if (fc->writeback_cache)
194 file_update_time(file);
195 }
196 if ((file->f_mode & FMODE_WRITE) && fc->writeback_cache)
197 fuse_link_write_file(file);
198 }
199
200 int fuse_open_common(struct inode *inode, struct file *file, bool isdir)
201 {
202 struct fuse_conn *fc = get_fuse_conn(inode);
203 int err;
204 bool lock_inode = (file->f_flags & O_TRUNC) &&
205 fc->atomic_o_trunc &&
206 fc->writeback_cache;
207
208 err = generic_file_open(inode, file);
209 if (err)
210 return err;
211
212 if (lock_inode)
213 inode_lock(inode);
214
215 err = fuse_do_open(fc, get_node_id(inode), file, isdir);
216
217 if (!err)
218 fuse_finish_open(inode, file);
219
220 if (lock_inode)
221 inode_unlock(inode);
222
223 return err;
224 }
225
226 static void fuse_prepare_release(struct fuse_inode *fi, struct fuse_file *ff,
227 int flags, int opcode)
228 {
229 struct fuse_conn *fc = ff->fc;
230 struct fuse_req *req = ff->reserved_req;
231 struct fuse_release_in *inarg = &req->misc.release.in;
232
233 /* Inode is NULL on error path of fuse_create_open() */
234 if (likely(fi)) {
235 spin_lock(&fi->lock);
236 list_del(&ff->write_entry);
237 spin_unlock(&fi->lock);
238 }
239 spin_lock(&fc->lock);
240 if (!RB_EMPTY_NODE(&ff->polled_node))
241 rb_erase(&ff->polled_node, &fc->polled_files);
242 spin_unlock(&fc->lock);
243
244 wake_up_interruptible_all(&ff->poll_wait);
245
246 inarg->fh = ff->fh;
247 inarg->flags = flags;
248 req->in.h.opcode = opcode;
249 req->in.h.nodeid = ff->nodeid;
250 req->in.numargs = 1;
251 req->in.args[0].size = sizeof(struct fuse_release_in);
252 req->in.args[0].value = inarg;
253 }
254
255 void fuse_release_common(struct file *file, bool isdir)
256 {
257 struct fuse_inode *fi = get_fuse_inode(file_inode(file));
258 struct fuse_file *ff = file->private_data;
259 struct fuse_req *req = ff->reserved_req;
260 int opcode = isdir ? FUSE_RELEASEDIR : FUSE_RELEASE;
261
262 fuse_prepare_release(fi, ff, file->f_flags, opcode);
263
264 if (ff->flock) {
265 struct fuse_release_in *inarg = &req->misc.release.in;
266 inarg->release_flags |= FUSE_RELEASE_FLOCK_UNLOCK;
267 inarg->lock_owner = fuse_lock_owner_id(ff->fc,
268 (fl_owner_t) file);
269 }
270 /* Hold inode until release is finished */
271 req->misc.release.inode = igrab(file_inode(file));
272
273 /*
274 * Normally this will send the RELEASE request, however if
275 * some asynchronous READ or WRITE requests are outstanding,
276 * the sending will be delayed.
277 *
278 * Make the release synchronous if this is a fuseblk mount,
279 * synchronous RELEASE is allowed (and desirable) in this case
280 * because the server can be trusted not to screw up.
281 */
282 fuse_file_put(ff, ff->fc->destroy_req != NULL, isdir);
283 }
284
285 static int fuse_open(struct inode *inode, struct file *file)
286 {
287 return fuse_open_common(inode, file, false);
288 }
289
290 static int fuse_release(struct inode *inode, struct file *file)
291 {
292 struct fuse_conn *fc = get_fuse_conn(inode);
293
294 /* see fuse_vma_close() for !writeback_cache case */
295 if (fc->writeback_cache)
296 write_inode_now(inode, 1);
297
298 fuse_release_common(file, false);
299
300 /* return value is ignored by VFS */
301 return 0;
302 }
303
304 void fuse_sync_release(struct fuse_inode *fi, struct fuse_file *ff, int flags)
305 {
306 WARN_ON(refcount_read(&ff->count) > 1);
307 fuse_prepare_release(fi, ff, flags, FUSE_RELEASE);
308 /*
309 * iput(NULL) is a no-op and since the refcount is 1 and everything's
310 * synchronous, we are fine with not doing igrab() here"
311 */
312 fuse_file_put(ff, true, false);
313 }
314 EXPORT_SYMBOL_GPL(fuse_sync_release);
315
316 /*
317 * Scramble the ID space with XTEA, so that the value of the files_struct
318 * pointer is not exposed to userspace.
319 */
320 u64 fuse_lock_owner_id(struct fuse_conn *fc, fl_owner_t id)
321 {
322 u32 *k = fc->scramble_key;
323 u64 v = (unsigned long) id;
324 u32 v0 = v;
325 u32 v1 = v >> 32;
326 u32 sum = 0;
327 int i;
328
329 for (i = 0; i < 32; i++) {
330 v0 += ((v1 << 4 ^ v1 >> 5) + v1) ^ (sum + k[sum & 3]);
331 sum += 0x9E3779B9;
332 v1 += ((v0 << 4 ^ v0 >> 5) + v0) ^ (sum + k[sum>>11 & 3]);
333 }
334
335 return (u64) v0 + ((u64) v1 << 32);
336 }
337
338 static struct fuse_req *fuse_find_writeback(struct fuse_inode *fi,
339 pgoff_t idx_from, pgoff_t idx_to)
340 {
341 struct fuse_req *req;
342
343 list_for_each_entry(req, &fi->writepages, writepages_entry) {
344 pgoff_t curr_index;
345
346 WARN_ON(get_fuse_inode(req->inode) != fi);
347 curr_index = req->misc.write.in.offset >> PAGE_SHIFT;
348 if (idx_from < curr_index + req->num_pages &&
349 curr_index <= idx_to) {
350 return req;
351 }
352 }
353 return NULL;
354 }
355
356 /*
357 * Check if any page in a range is under writeback
358 *
359 * This is currently done by walking the list of writepage requests
360 * for the inode, which can be pretty inefficient.
361 */
362 static bool fuse_range_is_writeback(struct inode *inode, pgoff_t idx_from,
363 pgoff_t idx_to)
364 {
365 struct fuse_inode *fi = get_fuse_inode(inode);
366 bool found;
367
368 spin_lock(&fi->lock);
369 found = fuse_find_writeback(fi, idx_from, idx_to);
370 spin_unlock(&fi->lock);
371
372 return found;
373 }
374
375 static inline bool fuse_page_is_writeback(struct inode *inode, pgoff_t index)
376 {
377 return fuse_range_is_writeback(inode, index, index);
378 }
379
380 /*
381 * Wait for page writeback to be completed.
382 *
383 * Since fuse doesn't rely on the VM writeback tracking, this has to
384 * use some other means.
385 */
386 static int fuse_wait_on_page_writeback(struct inode *inode, pgoff_t index)
387 {
388 struct fuse_inode *fi = get_fuse_inode(inode);
389
390 wait_event(fi->page_waitq, !fuse_page_is_writeback(inode, index));
391 return 0;
392 }
393
394 /*
395 * Wait for all pending writepages on the inode to finish.
396 *
397 * This is currently done by blocking further writes with FUSE_NOWRITE
398 * and waiting for all sent writes to complete.
399 *
400 * This must be called under i_mutex, otherwise the FUSE_NOWRITE usage
401 * could conflict with truncation.
402 */
403 static void fuse_sync_writes(struct inode *inode)
404 {
405 fuse_set_nowrite(inode);
406 fuse_release_nowrite(inode);
407 }
408
409 static int fuse_flush(struct file *file, fl_owner_t id)
410 {
411 struct inode *inode = file_inode(file);
412 struct fuse_conn *fc = get_fuse_conn(inode);
413 struct fuse_file *ff = file->private_data;
414 struct fuse_req *req;
415 struct fuse_flush_in inarg;
416 int err;
417
418 if (is_bad_inode(inode))
419 return -EIO;
420
421 if (fc->no_flush)
422 return 0;
423
424 err = write_inode_now(inode, 1);
425 if (err)
426 return err;
427
428 inode_lock(inode);
429 fuse_sync_writes(inode);
430 inode_unlock(inode);
431
432 err = filemap_check_errors(file->f_mapping);
433 if (err)
434 return err;
435
436 req = fuse_get_req_nofail_nopages(fc, file);
437 memset(&inarg, 0, sizeof(inarg));
438 inarg.fh = ff->fh;
439 inarg.lock_owner = fuse_lock_owner_id(fc, id);
440 req->in.h.opcode = FUSE_FLUSH;
441 req->in.h.nodeid = get_node_id(inode);
442 req->in.numargs = 1;
443 req->in.args[0].size = sizeof(inarg);
444 req->in.args[0].value = &inarg;
445 __set_bit(FR_FORCE, &req->flags);
446 fuse_request_send(fc, req);
447 err = req->out.h.error;
448 fuse_put_request(fc, req);
449 if (err == -ENOSYS) {
450 fc->no_flush = 1;
451 err = 0;
452 }
453 return err;
454 }
455
456 int fuse_fsync_common(struct file *file, loff_t start, loff_t end,
457 int datasync, int opcode)
458 {
459 struct inode *inode = file->f_mapping->host;
460 struct fuse_conn *fc = get_fuse_conn(inode);
461 struct fuse_file *ff = file->private_data;
462 FUSE_ARGS(args);
463 struct fuse_fsync_in inarg;
464
465 memset(&inarg, 0, sizeof(inarg));
466 inarg.fh = ff->fh;
467 inarg.fsync_flags = datasync ? FUSE_FSYNC_FDATASYNC : 0;
468 args.in.h.opcode = opcode;
469 args.in.h.nodeid = get_node_id(inode);
470 args.in.numargs = 1;
471 args.in.args[0].size = sizeof(inarg);
472 args.in.args[0].value = &inarg;
473 return fuse_simple_request(fc, &args);
474 }
475
476 static int fuse_fsync(struct file *file, loff_t start, loff_t end,
477 int datasync)
478 {
479 struct inode *inode = file->f_mapping->host;
480 struct fuse_conn *fc = get_fuse_conn(inode);
481 int err;
482
483 if (is_bad_inode(inode))
484 return -EIO;
485
486 inode_lock(inode);
487
488 /*
489 * Start writeback against all dirty pages of the inode, then
490 * wait for all outstanding writes, before sending the FSYNC
491 * request.
492 */
493 err = file_write_and_wait_range(file, start, end);
494 if (err)
495 goto out;
496
497 fuse_sync_writes(inode);
498
499 /*
500 * Due to implementation of fuse writeback
501 * file_write_and_wait_range() does not catch errors.
502 * We have to do this directly after fuse_sync_writes()
503 */
504 err = file_check_and_advance_wb_err(file);
505 if (err)
506 goto out;
507
508 err = sync_inode_metadata(inode, 1);
509 if (err)
510 goto out;
511
512 if (fc->no_fsync)
513 goto out;
514
515 err = fuse_fsync_common(file, start, end, datasync, FUSE_FSYNC);
516 if (err == -ENOSYS) {
517 fc->no_fsync = 1;
518 err = 0;
519 }
520 out:
521 inode_unlock(inode);
522
523 return err;
524 }
525
526 void fuse_read_fill(struct fuse_req *req, struct file *file, loff_t pos,
527 size_t count, int opcode)
528 {
529 struct fuse_read_in *inarg = &req->misc.read.in;
530 struct fuse_file *ff = file->private_data;
531
532 inarg->fh = ff->fh;
533 inarg->offset = pos;
534 inarg->size = count;
535 inarg->flags = file->f_flags;
536 req->in.h.opcode = opcode;
537 req->in.h.nodeid = ff->nodeid;
538 req->in.numargs = 1;
539 req->in.args[0].size = sizeof(struct fuse_read_in);
540 req->in.args[0].value = inarg;
541 req->out.argvar = 1;
542 req->out.numargs = 1;
543 req->out.args[0].size = count;
544 }
545
546 static void fuse_release_user_pages(struct fuse_req *req, bool should_dirty)
547 {
548 unsigned i;
549
550 for (i = 0; i < req->num_pages; i++) {
551 struct page *page = req->pages[i];
552 if (should_dirty)
553 set_page_dirty_lock(page);
554 put_page(page);
555 }
556 }
557
558 static void fuse_io_release(struct kref *kref)
559 {
560 kfree(container_of(kref, struct fuse_io_priv, refcnt));
561 }
562
563 static ssize_t fuse_get_res_by_io(struct fuse_io_priv *io)
564 {
565 if (io->err)
566 return io->err;
567
568 if (io->bytes >= 0 && io->write)
569 return -EIO;
570
571 return io->bytes < 0 ? io->size : io->bytes;
572 }
573
574 /**
575 * In case of short read, the caller sets 'pos' to the position of
576 * actual end of fuse request in IO request. Otherwise, if bytes_requested
577 * == bytes_transferred or rw == WRITE, the caller sets 'pos' to -1.
578 *
579 * An example:
580 * User requested DIO read of 64K. It was splitted into two 32K fuse requests,
581 * both submitted asynchronously. The first of them was ACKed by userspace as
582 * fully completed (req->out.args[0].size == 32K) resulting in pos == -1. The
583 * second request was ACKed as short, e.g. only 1K was read, resulting in
584 * pos == 33K.
585 *
586 * Thus, when all fuse requests are completed, the minimal non-negative 'pos'
587 * will be equal to the length of the longest contiguous fragment of
588 * transferred data starting from the beginning of IO request.
589 */
590 static void fuse_aio_complete(struct fuse_io_priv *io, int err, ssize_t pos)
591 {
592 int left;
593
594 spin_lock(&io->lock);
595 if (err)
596 io->err = io->err ? : err;
597 else if (pos >= 0 && (io->bytes < 0 || pos < io->bytes))
598 io->bytes = pos;
599
600 left = --io->reqs;
601 if (!left && io->blocking)
602 complete(io->done);
603 spin_unlock(&io->lock);
604
605 if (!left && !io->blocking) {
606 ssize_t res = fuse_get_res_by_io(io);
607
608 if (res >= 0) {
609 struct inode *inode = file_inode(io->iocb->ki_filp);
610 struct fuse_conn *fc = get_fuse_conn(inode);
611 struct fuse_inode *fi = get_fuse_inode(inode);
612
613 spin_lock(&fi->lock);
614 fi->attr_version = atomic64_inc_return(&fc->attr_version);
615 spin_unlock(&fi->lock);
616 }
617
618 io->iocb->ki_complete(io->iocb, res, 0);
619 }
620
621 kref_put(&io->refcnt, fuse_io_release);
622 }
623
624 static void fuse_aio_complete_req(struct fuse_conn *fc, struct fuse_req *req)
625 {
626 struct fuse_io_priv *io = req->io;
627 ssize_t pos = -1;
628
629 fuse_release_user_pages(req, io->should_dirty);
630
631 if (io->write) {
632 if (req->misc.write.in.size != req->misc.write.out.size)
633 pos = req->misc.write.in.offset - io->offset +
634 req->misc.write.out.size;
635 } else {
636 if (req->misc.read.in.size != req->out.args[0].size)
637 pos = req->misc.read.in.offset - io->offset +
638 req->out.args[0].size;
639 }
640
641 fuse_aio_complete(io, req->out.h.error, pos);
642 }
643
644 static size_t fuse_async_req_send(struct fuse_conn *fc, struct fuse_req *req,
645 size_t num_bytes, struct fuse_io_priv *io)
646 {
647 spin_lock(&io->lock);
648 kref_get(&io->refcnt);
649 io->size += num_bytes;
650 io->reqs++;
651 spin_unlock(&io->lock);
652
653 req->io = io;
654 req->end = fuse_aio_complete_req;
655
656 __fuse_get_request(req);
657 fuse_request_send_background(fc, req);
658
659 return num_bytes;
660 }
661
662 static size_t fuse_send_read(struct fuse_req *req, struct fuse_io_priv *io,
663 loff_t pos, size_t count, fl_owner_t owner)
664 {
665 struct file *file = io->iocb->ki_filp;
666 struct fuse_file *ff = file->private_data;
667 struct fuse_conn *fc = ff->fc;
668
669 fuse_read_fill(req, file, pos, count, FUSE_READ);
670 if (owner != NULL) {
671 struct fuse_read_in *inarg = &req->misc.read.in;
672
673 inarg->read_flags |= FUSE_READ_LOCKOWNER;
674 inarg->lock_owner = fuse_lock_owner_id(fc, owner);
675 }
676
677 if (io->async)
678 return fuse_async_req_send(fc, req, count, io);
679
680 fuse_request_send(fc, req);
681 return req->out.args[0].size;
682 }
683
684 static void fuse_read_update_size(struct inode *inode, loff_t size,
685 u64 attr_ver)
686 {
687 struct fuse_conn *fc = get_fuse_conn(inode);
688 struct fuse_inode *fi = get_fuse_inode(inode);
689
690 spin_lock(&fi->lock);
691 if (attr_ver == fi->attr_version && size < inode->i_size &&
692 !test_bit(FUSE_I_SIZE_UNSTABLE, &fi->state)) {
693 fi->attr_version = atomic64_inc_return(&fc->attr_version);
694 i_size_write(inode, size);
695 }
696 spin_unlock(&fi->lock);
697 }
698
699 static void fuse_short_read(struct fuse_req *req, struct inode *inode,
700 u64 attr_ver)
701 {
702 size_t num_read = req->out.args[0].size;
703 struct fuse_conn *fc = get_fuse_conn(inode);
704
705 if (fc->writeback_cache) {
706 /*
707 * A hole in a file. Some data after the hole are in page cache,
708 * but have not reached the client fs yet. So, the hole is not
709 * present there.
710 */
711 int i;
712 int start_idx = num_read >> PAGE_SHIFT;
713 size_t off = num_read & (PAGE_SIZE - 1);
714
715 for (i = start_idx; i < req->num_pages; i++) {
716 zero_user_segment(req->pages[i], off, PAGE_SIZE);
717 off = 0;
718 }
719 } else {
720 loff_t pos = page_offset(req->pages[0]) + num_read;
721 fuse_read_update_size(inode, pos, attr_ver);
722 }
723 }
724
725 static int fuse_do_readpage(struct file *file, struct page *page)
726 {
727 struct kiocb iocb;
728 struct fuse_io_priv io;
729 struct inode *inode = page->mapping->host;
730 struct fuse_conn *fc = get_fuse_conn(inode);
731 struct fuse_req *req;
732 size_t num_read;
733 loff_t pos = page_offset(page);
734 size_t count = PAGE_SIZE;
735 u64 attr_ver;
736 int err;
737
738 /*
739 * Page writeback can extend beyond the lifetime of the
740 * page-cache page, so make sure we read a properly synced
741 * page.
742 */
743 fuse_wait_on_page_writeback(inode, page->index);
744
745 req = fuse_get_req(fc, 1);
746 if (IS_ERR(req))
747 return PTR_ERR(req);
748
749 attr_ver = fuse_get_attr_version(fc);
750
751 req->out.page_zeroing = 1;
752 req->out.argpages = 1;
753 req->num_pages = 1;
754 req->pages[0] = page;
755 req->page_descs[0].length = count;
756 init_sync_kiocb(&iocb, file);
757 io = (struct fuse_io_priv) FUSE_IO_PRIV_SYNC(&iocb);
758 num_read = fuse_send_read(req, &io, pos, count, NULL);
759 err = req->out.h.error;
760
761 if (!err) {
762 /*
763 * Short read means EOF. If file size is larger, truncate it
764 */
765 if (num_read < count)
766 fuse_short_read(req, inode, attr_ver);
767
768 SetPageUptodate(page);
769 }
770
771 fuse_put_request(fc, req);
772
773 return err;
774 }
775
776 static int fuse_readpage(struct file *file, struct page *page)
777 {
778 struct inode *inode = page->mapping->host;
779 int err;
780
781 err = -EIO;
782 if (is_bad_inode(inode))
783 goto out;
784
785 err = fuse_do_readpage(file, page);
786 fuse_invalidate_atime(inode);
787 out:
788 unlock_page(page);
789 return err;
790 }
791
792 static void fuse_readpages_end(struct fuse_conn *fc, struct fuse_req *req)
793 {
794 int i;
795 size_t count = req->misc.read.in.size;
796 size_t num_read = req->out.args[0].size;
797 struct address_space *mapping = NULL;
798
799 for (i = 0; mapping == NULL && i < req->num_pages; i++)
800 mapping = req->pages[i]->mapping;
801
802 if (mapping) {
803 struct inode *inode = mapping->host;
804
805 /*
806 * Short read means EOF. If file size is larger, truncate it
807 */
808 if (!req->out.h.error && num_read < count)
809 fuse_short_read(req, inode, req->misc.read.attr_ver);
810
811 fuse_invalidate_atime(inode);
812 }
813
814 for (i = 0; i < req->num_pages; i++) {
815 struct page *page = req->pages[i];
816 if (!req->out.h.error)
817 SetPageUptodate(page);
818 else
819 SetPageError(page);
820 unlock_page(page);
821 put_page(page);
822 }
823 if (req->ff)
824 fuse_file_put(req->ff, false, false);
825 }
826
827 static void fuse_send_readpages(struct fuse_req *req, struct file *file)
828 {
829 struct fuse_file *ff = file->private_data;
830 struct fuse_conn *fc = ff->fc;
831 loff_t pos = page_offset(req->pages[0]);
832 size_t count = req->num_pages << PAGE_SHIFT;
833
834 req->out.argpages = 1;
835 req->out.page_zeroing = 1;
836 req->out.page_replace = 1;
837 fuse_read_fill(req, file, pos, count, FUSE_READ);
838 req->misc.read.attr_ver = fuse_get_attr_version(fc);
839 if (fc->async_read) {
840 req->ff = fuse_file_get(ff);
841 req->end = fuse_readpages_end;
842 fuse_request_send_background(fc, req);
843 } else {
844 fuse_request_send(fc, req);
845 fuse_readpages_end(fc, req);
846 fuse_put_request(fc, req);
847 }
848 }
849
850 struct fuse_fill_data {
851 struct fuse_req *req;
852 struct file *file;
853 struct inode *inode;
854 unsigned nr_pages;
855 };
856
857 static int fuse_readpages_fill(void *_data, struct page *page)
858 {
859 struct fuse_fill_data *data = _data;
860 struct fuse_req *req = data->req;
861 struct inode *inode = data->inode;
862 struct fuse_conn *fc = get_fuse_conn(inode);
863
864 fuse_wait_on_page_writeback(inode, page->index);
865
866 if (req->num_pages &&
867 (req->num_pages == fc->max_pages ||
868 (req->num_pages + 1) * PAGE_SIZE > fc->max_read ||
869 req->pages[req->num_pages - 1]->index + 1 != page->index)) {
870 unsigned int nr_alloc = min_t(unsigned int, data->nr_pages,
871 fc->max_pages);
872 fuse_send_readpages(req, data->file);
873 if (fc->async_read)
874 req = fuse_get_req_for_background(fc, nr_alloc);
875 else
876 req = fuse_get_req(fc, nr_alloc);
877
878 data->req = req;
879 if (IS_ERR(req)) {
880 unlock_page(page);
881 return PTR_ERR(req);
882 }
883 }
884
885 if (WARN_ON(req->num_pages >= req->max_pages)) {
886 unlock_page(page);
887 fuse_put_request(fc, req);
888 return -EIO;
889 }
890
891 get_page(page);
892 req->pages[req->num_pages] = page;
893 req->page_descs[req->num_pages].length = PAGE_SIZE;
894 req->num_pages++;
895 data->nr_pages--;
896 return 0;
897 }
898
899 static int fuse_readpages(struct file *file, struct address_space *mapping,
900 struct list_head *pages, unsigned nr_pages)
901 {
902 struct inode *inode = mapping->host;
903 struct fuse_conn *fc = get_fuse_conn(inode);
904 struct fuse_fill_data data;
905 int err;
906 unsigned int nr_alloc = min_t(unsigned int, nr_pages, fc->max_pages);
907
908 err = -EIO;
909 if (is_bad_inode(inode))
910 goto out;
911
912 data.file = file;
913 data.inode = inode;
914 if (fc->async_read)
915 data.req = fuse_get_req_for_background(fc, nr_alloc);
916 else
917 data.req = fuse_get_req(fc, nr_alloc);
918 data.nr_pages = nr_pages;
919 err = PTR_ERR(data.req);
920 if (IS_ERR(data.req))
921 goto out;
922
923 err = read_cache_pages(mapping, pages, fuse_readpages_fill, &data);
924 if (!err) {
925 if (data.req->num_pages)
926 fuse_send_readpages(data.req, file);
927 else
928 fuse_put_request(fc, data.req);
929 }
930 out:
931 return err;
932 }
933
934 static ssize_t fuse_cache_read_iter(struct kiocb *iocb, struct iov_iter *to)
935 {
936 struct inode *inode = iocb->ki_filp->f_mapping->host;
937 struct fuse_conn *fc = get_fuse_conn(inode);
938
939 /*
940 * In auto invalidate mode, always update attributes on read.
941 * Otherwise, only update if we attempt to read past EOF (to ensure
942 * i_size is up to date).
943 */
944 if (fc->auto_inval_data ||
945 (iocb->ki_pos + iov_iter_count(to) > i_size_read(inode))) {
946 int err;
947 err = fuse_update_attributes(inode, iocb->ki_filp);
948 if (err)
949 return err;
950 }
951
952 return generic_file_read_iter(iocb, to);
953 }
954
955 static void fuse_write_fill(struct fuse_req *req, struct fuse_file *ff,
956 loff_t pos, size_t count)
957 {
958 struct fuse_write_in *inarg = &req->misc.write.in;
959 struct fuse_write_out *outarg = &req->misc.write.out;
960
961 inarg->fh = ff->fh;
962 inarg->offset = pos;
963 inarg->size = count;
964 req->in.h.opcode = FUSE_WRITE;
965 req->in.h.nodeid = ff->nodeid;
966 req->in.numargs = 2;
967 if (ff->fc->minor < 9)
968 req->in.args[0].size = FUSE_COMPAT_WRITE_IN_SIZE;
969 else
970 req->in.args[0].size = sizeof(struct fuse_write_in);
971 req->in.args[0].value = inarg;
972 req->in.args[1].size = count;
973 req->out.numargs = 1;
974 req->out.args[0].size = sizeof(struct fuse_write_out);
975 req->out.args[0].value = outarg;
976 }
977
978 static size_t fuse_send_write(struct fuse_req *req, struct fuse_io_priv *io,
979 loff_t pos, size_t count, fl_owner_t owner)
980 {
981 struct kiocb *iocb = io->iocb;
982 struct file *file = iocb->ki_filp;
983 struct fuse_file *ff = file->private_data;
984 struct fuse_conn *fc = ff->fc;
985 struct fuse_write_in *inarg = &req->misc.write.in;
986
987 fuse_write_fill(req, ff, pos, count);
988 inarg->flags = file->f_flags;
989 if (iocb->ki_flags & IOCB_DSYNC)
990 inarg->flags |= O_DSYNC;
991 if (iocb->ki_flags & IOCB_SYNC)
992 inarg->flags |= O_SYNC;
993 if (owner != NULL) {
994 inarg->write_flags |= FUSE_WRITE_LOCKOWNER;
995 inarg->lock_owner = fuse_lock_owner_id(fc, owner);
996 }
997
998 if (io->async)
999 return fuse_async_req_send(fc, req, count, io);
1000
1001 fuse_request_send(fc, req);
1002 return req->misc.write.out.size;
1003 }
1004
1005 bool fuse_write_update_size(struct inode *inode, loff_t pos)
1006 {
1007 struct fuse_conn *fc = get_fuse_conn(inode);
1008 struct fuse_inode *fi = get_fuse_inode(inode);
1009 bool ret = false;
1010
1011 spin_lock(&fi->lock);
1012 fi->attr_version = atomic64_inc_return(&fc->attr_version);
1013 if (pos > inode->i_size) {
1014 i_size_write(inode, pos);
1015 ret = true;
1016 }
1017 spin_unlock(&fi->lock);
1018
1019 return ret;
1020 }
1021
1022 static size_t fuse_send_write_pages(struct fuse_req *req, struct kiocb *iocb,
1023 struct inode *inode, loff_t pos,
1024 size_t count)
1025 {
1026 size_t res;
1027 unsigned offset;
1028 unsigned i;
1029 struct fuse_io_priv io = FUSE_IO_PRIV_SYNC(iocb);
1030
1031 for (i = 0; i < req->num_pages; i++)
1032 fuse_wait_on_page_writeback(inode, req->pages[i]->index);
1033
1034 res = fuse_send_write(req, &io, pos, count, NULL);
1035
1036 offset = req->page_descs[0].offset;
1037 count = res;
1038 for (i = 0; i < req->num_pages; i++) {
1039 struct page *page = req->pages[i];
1040
1041 if (!req->out.h.error && !offset && count >= PAGE_SIZE)
1042 SetPageUptodate(page);
1043
1044 if (count > PAGE_SIZE - offset)
1045 count -= PAGE_SIZE - offset;
1046 else
1047 count = 0;
1048 offset = 0;
1049
1050 unlock_page(page);
1051 put_page(page);
1052 }
1053
1054 return res;
1055 }
1056
1057 static ssize_t fuse_fill_write_pages(struct fuse_req *req,
1058 struct address_space *mapping,
1059 struct iov_iter *ii, loff_t pos)
1060 {
1061 struct fuse_conn *fc = get_fuse_conn(mapping->host);
1062 unsigned offset = pos & (PAGE_SIZE - 1);
1063 size_t count = 0;
1064 int err;
1065
1066 req->in.argpages = 1;
1067 req->page_descs[0].offset = offset;
1068
1069 do {
1070 size_t tmp;
1071 struct page *page;
1072 pgoff_t index = pos >> PAGE_SHIFT;
1073 size_t bytes = min_t(size_t, PAGE_SIZE - offset,
1074 iov_iter_count(ii));
1075
1076 bytes = min_t(size_t, bytes, fc->max_write - count);
1077
1078 again:
1079 err = -EFAULT;
1080 if (iov_iter_fault_in_readable(ii, bytes))
1081 break;
1082
1083 err = -ENOMEM;
1084 page = grab_cache_page_write_begin(mapping, index, 0);
1085 if (!page)
1086 break;
1087
1088 if (mapping_writably_mapped(mapping))
1089 flush_dcache_page(page);
1090
1091 tmp = iov_iter_copy_from_user_atomic(page, ii, offset, bytes);
1092 flush_dcache_page(page);
1093
1094 iov_iter_advance(ii, tmp);
1095 if (!tmp) {
1096 unlock_page(page);
1097 put_page(page);
1098 bytes = min(bytes, iov_iter_single_seg_count(ii));
1099 goto again;
1100 }
1101
1102 err = 0;
1103 req->pages[req->num_pages] = page;
1104 req->page_descs[req->num_pages].length = tmp;
1105 req->num_pages++;
1106
1107 count += tmp;
1108 pos += tmp;
1109 offset += tmp;
1110 if (offset == PAGE_SIZE)
1111 offset = 0;
1112
1113 if (!fc->big_writes)
1114 break;
1115 } while (iov_iter_count(ii) && count < fc->max_write &&
1116 req->num_pages < req->max_pages && offset == 0);
1117
1118 return count > 0 ? count : err;
1119 }
1120
1121 static inline unsigned int fuse_wr_pages(loff_t pos, size_t len,
1122 unsigned int max_pages)
1123 {
1124 return min_t(unsigned int,
1125 ((pos + len - 1) >> PAGE_SHIFT) -
1126 (pos >> PAGE_SHIFT) + 1,
1127 max_pages);
1128 }
1129
1130 static ssize_t fuse_perform_write(struct kiocb *iocb,
1131 struct address_space *mapping,
1132 struct iov_iter *ii, loff_t pos)
1133 {
1134 struct inode *inode = mapping->host;
1135 struct fuse_conn *fc = get_fuse_conn(inode);
1136 struct fuse_inode *fi = get_fuse_inode(inode);
1137 int err = 0;
1138 ssize_t res = 0;
1139
1140 if (inode->i_size < pos + iov_iter_count(ii))
1141 set_bit(FUSE_I_SIZE_UNSTABLE, &fi->state);
1142
1143 do {
1144 struct fuse_req *req;
1145 ssize_t count;
1146 unsigned int nr_pages = fuse_wr_pages(pos, iov_iter_count(ii),
1147 fc->max_pages);
1148
1149 req = fuse_get_req(fc, nr_pages);
1150 if (IS_ERR(req)) {
1151 err = PTR_ERR(req);
1152 break;
1153 }
1154
1155 count = fuse_fill_write_pages(req, mapping, ii, pos);
1156 if (count <= 0) {
1157 err = count;
1158 } else {
1159 size_t num_written;
1160
1161 num_written = fuse_send_write_pages(req, iocb, inode,
1162 pos, count);
1163 err = req->out.h.error;
1164 if (!err) {
1165 res += num_written;
1166 pos += num_written;
1167
1168 /* break out of the loop on short write */
1169 if (num_written != count)
1170 err = -EIO;
1171 }
1172 }
1173 fuse_put_request(fc, req);
1174 } while (!err && iov_iter_count(ii));
1175
1176 if (res > 0)
1177 fuse_write_update_size(inode, pos);
1178
1179 clear_bit(FUSE_I_SIZE_UNSTABLE, &fi->state);
1180 fuse_invalidate_attr(inode);
1181
1182 return res > 0 ? res : err;
1183 }
1184
1185 static ssize_t fuse_cache_write_iter(struct kiocb *iocb, struct iov_iter *from)
1186 {
1187 struct file *file = iocb->ki_filp;
1188 struct address_space *mapping = file->f_mapping;
1189 ssize_t written = 0;
1190 ssize_t written_buffered = 0;
1191 struct inode *inode = mapping->host;
1192 ssize_t err;
1193 loff_t endbyte = 0;
1194
1195 if (get_fuse_conn(inode)->writeback_cache) {
1196 /* Update size (EOF optimization) and mode (SUID clearing) */
1197 err = fuse_update_attributes(mapping->host, file);
1198 if (err)
1199 return err;
1200
1201 return generic_file_write_iter(iocb, from);
1202 }
1203
1204 inode_lock(inode);
1205
1206 /* We can write back this queue in page reclaim */
1207 current->backing_dev_info = inode_to_bdi(inode);
1208
1209 err = generic_write_checks(iocb, from);
1210 if (err <= 0)
1211 goto out;
1212
1213 err = file_remove_privs(file);
1214 if (err)
1215 goto out;
1216
1217 err = file_update_time(file);
1218 if (err)
1219 goto out;
1220
1221 if (iocb->ki_flags & IOCB_DIRECT) {
1222 loff_t pos = iocb->ki_pos;
1223 written = generic_file_direct_write(iocb, from);
1224 if (written < 0 || !iov_iter_count(from))
1225 goto out;
1226
1227 pos += written;
1228
1229 written_buffered = fuse_perform_write(iocb, mapping, from, pos);
1230 if (written_buffered < 0) {
1231 err = written_buffered;
1232 goto out;
1233 }
1234 endbyte = pos + written_buffered - 1;
1235
1236 err = filemap_write_and_wait_range(file->f_mapping, pos,
1237 endbyte);
1238 if (err)
1239 goto out;
1240
1241 invalidate_mapping_pages(file->f_mapping,
1242 pos >> PAGE_SHIFT,
1243 endbyte >> PAGE_SHIFT);
1244
1245 written += written_buffered;
1246 iocb->ki_pos = pos + written_buffered;
1247 } else {
1248 written = fuse_perform_write(iocb, mapping, from, iocb->ki_pos);
1249 if (written >= 0)
1250 iocb->ki_pos += written;
1251 }
1252 out:
1253 current->backing_dev_info = NULL;
1254 inode_unlock(inode);
1255 if (written > 0)
1256 written = generic_write_sync(iocb, written);
1257
1258 return written ? written : err;
1259 }
1260
1261 static inline void fuse_page_descs_length_init(struct fuse_req *req,
1262 unsigned index, unsigned nr_pages)
1263 {
1264 int i;
1265
1266 for (i = index; i < index + nr_pages; i++)
1267 req->page_descs[i].length = PAGE_SIZE -
1268 req->page_descs[i].offset;
1269 }
1270
1271 static inline unsigned long fuse_get_user_addr(const struct iov_iter *ii)
1272 {
1273 return (unsigned long)ii->iov->iov_base + ii->iov_offset;
1274 }
1275
1276 static inline size_t fuse_get_frag_size(const struct iov_iter *ii,
1277 size_t max_size)
1278 {
1279 return min(iov_iter_single_seg_count(ii), max_size);
1280 }
1281
1282 static int fuse_get_user_pages(struct fuse_req *req, struct iov_iter *ii,
1283 size_t *nbytesp, int write)
1284 {
1285 size_t nbytes = 0; /* # bytes already packed in req */
1286 ssize_t ret = 0;
1287
1288 /* Special case for kernel I/O: can copy directly into the buffer */
1289 if (iov_iter_is_kvec(ii)) {
1290 unsigned long user_addr = fuse_get_user_addr(ii);
1291 size_t frag_size = fuse_get_frag_size(ii, *nbytesp);
1292
1293 if (write)
1294 req->in.args[1].value = (void *) user_addr;
1295 else
1296 req->out.args[0].value = (void *) user_addr;
1297
1298 iov_iter_advance(ii, frag_size);
1299 *nbytesp = frag_size;
1300 return 0;
1301 }
1302
1303 while (nbytes < *nbytesp && req->num_pages < req->max_pages) {
1304 unsigned npages;
1305 size_t start;
1306 ret = iov_iter_get_pages(ii, &req->pages[req->num_pages],
1307 *nbytesp - nbytes,
1308 req->max_pages - req->num_pages,
1309 &start);
1310 if (ret < 0)
1311 break;
1312
1313 iov_iter_advance(ii, ret);
1314 nbytes += ret;
1315
1316 ret += start;
1317 npages = (ret + PAGE_SIZE - 1) / PAGE_SIZE;
1318
1319 req->page_descs[req->num_pages].offset = start;
1320 fuse_page_descs_length_init(req, req->num_pages, npages);
1321
1322 req->num_pages += npages;
1323 req->page_descs[req->num_pages - 1].length -=
1324 (PAGE_SIZE - ret) & (PAGE_SIZE - 1);
1325 }
1326
1327 if (write)
1328 req->in.argpages = 1;
1329 else
1330 req->out.argpages = 1;
1331
1332 *nbytesp = nbytes;
1333
1334 return ret < 0 ? ret : 0;
1335 }
1336
1337 ssize_t fuse_direct_io(struct fuse_io_priv *io, struct iov_iter *iter,
1338 loff_t *ppos, int flags)
1339 {
1340 int write = flags & FUSE_DIO_WRITE;
1341 int cuse = flags & FUSE_DIO_CUSE;
1342 struct file *file = io->iocb->ki_filp;
1343 struct inode *inode = file->f_mapping->host;
1344 struct fuse_file *ff = file->private_data;
1345 struct fuse_conn *fc = ff->fc;
1346 size_t nmax = write ? fc->max_write : fc->max_read;
1347 loff_t pos = *ppos;
1348 size_t count = iov_iter_count(iter);
1349 pgoff_t idx_from = pos >> PAGE_SHIFT;
1350 pgoff_t idx_to = (pos + count - 1) >> PAGE_SHIFT;
1351 ssize_t res = 0;
1352 struct fuse_req *req;
1353 int err = 0;
1354
1355 if (io->async)
1356 req = fuse_get_req_for_background(fc, iov_iter_npages(iter,
1357 fc->max_pages));
1358 else
1359 req = fuse_get_req(fc, iov_iter_npages(iter, fc->max_pages));
1360 if (IS_ERR(req))
1361 return PTR_ERR(req);
1362
1363 if (!cuse && fuse_range_is_writeback(inode, idx_from, idx_to)) {
1364 if (!write)
1365 inode_lock(inode);
1366 fuse_sync_writes(inode);
1367 if (!write)
1368 inode_unlock(inode);
1369 }
1370
1371 io->should_dirty = !write && iter_is_iovec(iter);
1372 while (count) {
1373 size_t nres;
1374 fl_owner_t owner = current->files;
1375 size_t nbytes = min(count, nmax);
1376 err = fuse_get_user_pages(req, iter, &nbytes, write);
1377 if (err && !nbytes)
1378 break;
1379
1380 if (write) {
1381 if (!capable(CAP_FSETID)) {
1382 struct fuse_write_in *inarg;
1383
1384 inarg = &req->misc.write.in;
1385 inarg->write_flags |= FUSE_WRITE_KILL_PRIV;
1386 }
1387 nres = fuse_send_write(req, io, pos, nbytes, owner);
1388 } else {
1389 nres = fuse_send_read(req, io, pos, nbytes, owner);
1390 }
1391
1392 if (!io->async)
1393 fuse_release_user_pages(req, io->should_dirty);
1394 if (req->out.h.error) {
1395 err = req->out.h.error;
1396 break;
1397 } else if (nres > nbytes) {
1398 res = 0;
1399 err = -EIO;
1400 break;
1401 }
1402 count -= nres;
1403 res += nres;
1404 pos += nres;
1405 if (nres != nbytes)
1406 break;
1407 if (count) {
1408 fuse_put_request(fc, req);
1409 if (io->async)
1410 req = fuse_get_req_for_background(fc,
1411 iov_iter_npages(iter, fc->max_pages));
1412 else
1413 req = fuse_get_req(fc, iov_iter_npages(iter,
1414 fc->max_pages));
1415 if (IS_ERR(req))
1416 break;
1417 }
1418 }
1419 if (!IS_ERR(req))
1420 fuse_put_request(fc, req);
1421 if (res > 0)
1422 *ppos = pos;
1423
1424 return res > 0 ? res : err;
1425 }
1426 EXPORT_SYMBOL_GPL(fuse_direct_io);
1427
1428 static ssize_t __fuse_direct_read(struct fuse_io_priv *io,
1429 struct iov_iter *iter,
1430 loff_t *ppos)
1431 {
1432 ssize_t res;
1433 struct inode *inode = file_inode(io->iocb->ki_filp);
1434
1435 res = fuse_direct_io(io, iter, ppos, 0);
1436
1437 fuse_invalidate_atime(inode);
1438
1439 return res;
1440 }
1441
1442 static ssize_t fuse_direct_IO(struct kiocb *iocb, struct iov_iter *iter);
1443
1444 static ssize_t fuse_direct_read_iter(struct kiocb *iocb, struct iov_iter *to)
1445 {
1446 ssize_t res;
1447
1448 if (!is_sync_kiocb(iocb) && iocb->ki_flags & IOCB_DIRECT) {
1449 res = fuse_direct_IO(iocb, to);
1450 } else {
1451 struct fuse_io_priv io = FUSE_IO_PRIV_SYNC(iocb);
1452
1453 res = __fuse_direct_read(&io, to, &iocb->ki_pos);
1454 }
1455
1456 return res;
1457 }
1458
1459 static ssize_t fuse_direct_write_iter(struct kiocb *iocb, struct iov_iter *from)
1460 {
1461 struct inode *inode = file_inode(iocb->ki_filp);
1462 struct fuse_io_priv io = FUSE_IO_PRIV_SYNC(iocb);
1463 ssize_t res;
1464
1465 /* Don't allow parallel writes to the same file */
1466 inode_lock(inode);
1467 res = generic_write_checks(iocb, from);
1468 if (res > 0) {
1469 if (!is_sync_kiocb(iocb) && iocb->ki_flags & IOCB_DIRECT) {
1470 res = fuse_direct_IO(iocb, from);
1471 } else {
1472 res = fuse_direct_io(&io, from, &iocb->ki_pos,
1473 FUSE_DIO_WRITE);
1474 }
1475 }
1476 fuse_invalidate_attr(inode);
1477 if (res > 0)
1478 fuse_write_update_size(inode, iocb->ki_pos);
1479 inode_unlock(inode);
1480
1481 return res;
1482 }
1483
1484 static ssize_t fuse_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
1485 {
1486 struct file *file = iocb->ki_filp;
1487 struct fuse_file *ff = file->private_data;
1488
1489 if (is_bad_inode(file_inode(file)))
1490 return -EIO;
1491
1492 if (!(ff->open_flags & FOPEN_DIRECT_IO))
1493 return fuse_cache_read_iter(iocb, to);
1494 else
1495 return fuse_direct_read_iter(iocb, to);
1496 }
1497
1498 static ssize_t fuse_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
1499 {
1500 struct file *file = iocb->ki_filp;
1501 struct fuse_file *ff = file->private_data;
1502
1503 if (is_bad_inode(file_inode(file)))
1504 return -EIO;
1505
1506 if (!(ff->open_flags & FOPEN_DIRECT_IO))
1507 return fuse_cache_write_iter(iocb, from);
1508 else
1509 return fuse_direct_write_iter(iocb, from);
1510 }
1511
1512 static void fuse_writepage_free(struct fuse_conn *fc, struct fuse_req *req)
1513 {
1514 int i;
1515
1516 for (i = 0; i < req->num_pages; i++)
1517 __free_page(req->pages[i]);
1518
1519 if (req->ff)
1520 fuse_file_put(req->ff, false, false);
1521 }
1522
1523 static void fuse_writepage_finish(struct fuse_conn *fc, struct fuse_req *req)
1524 {
1525 struct inode *inode = req->inode;
1526 struct fuse_inode *fi = get_fuse_inode(inode);
1527 struct backing_dev_info *bdi = inode_to_bdi(inode);
1528 int i;
1529
1530 list_del(&req->writepages_entry);
1531 for (i = 0; i < req->num_pages; i++) {
1532 dec_wb_stat(&bdi->wb, WB_WRITEBACK);
1533 dec_node_page_state(req->pages[i], NR_WRITEBACK_TEMP);
1534 wb_writeout_inc(&bdi->wb);
1535 }
1536 wake_up(&fi->page_waitq);
1537 }
1538
1539 /* Called under fi->lock, may release and reacquire it */
1540 static void fuse_send_writepage(struct fuse_conn *fc, struct fuse_req *req,
1541 loff_t size)
1542 __releases(fi->lock)
1543 __acquires(fi->lock)
1544 {
1545 struct fuse_req *aux, *next;
1546 struct fuse_inode *fi = get_fuse_inode(req->inode);
1547 struct fuse_write_in *inarg = &req->misc.write.in;
1548 __u64 data_size = req->num_pages * PAGE_SIZE;
1549 bool queued;
1550
1551 if (inarg->offset + data_size <= size) {
1552 inarg->size = data_size;
1553 } else if (inarg->offset < size) {
1554 inarg->size = size - inarg->offset;
1555 } else {
1556 /* Got truncated off completely */
1557 goto out_free;
1558 }
1559
1560 req->in.args[1].size = inarg->size;
1561 queued = fuse_request_queue_background(fc, req);
1562 /* Fails on broken connection only */
1563 if (unlikely(!queued))
1564 goto out_free;
1565
1566 fi->writectr++;
1567 return;
1568
1569 out_free:
1570 fuse_writepage_finish(fc, req);
1571 spin_unlock(&fi->lock);
1572
1573 /* After fuse_writepage_finish() aux request list is private */
1574 for (aux = req->misc.write.next; aux; aux = next) {
1575 next = aux->misc.write.next;
1576 aux->misc.write.next = NULL;
1577 fuse_writepage_free(fc, aux);
1578 fuse_put_request(fc, aux);
1579 }
1580
1581 fuse_writepage_free(fc, req);
1582 fuse_put_request(fc, req);
1583 spin_lock(&fi->lock);
1584 }
1585
1586 /*
1587 * If fi->writectr is positive (no truncate or fsync going on) send
1588 * all queued writepage requests.
1589 *
1590 * Called with fi->lock
1591 */
1592 void fuse_flush_writepages(struct inode *inode)
1593 __releases(fi->lock)
1594 __acquires(fi->lock)
1595 {
1596 struct fuse_conn *fc = get_fuse_conn(inode);
1597 struct fuse_inode *fi = get_fuse_inode(inode);
1598 loff_t crop = i_size_read(inode);
1599 struct fuse_req *req;
1600
1601 while (fi->writectr >= 0 && !list_empty(&fi->queued_writes)) {
1602 req = list_entry(fi->queued_writes.next, struct fuse_req, list);
1603 list_del_init(&req->list);
1604 fuse_send_writepage(fc, req, crop);
1605 }
1606 }
1607
1608 static void fuse_writepage_end(struct fuse_conn *fc, struct fuse_req *req)
1609 {
1610 struct inode *inode = req->inode;
1611 struct fuse_inode *fi = get_fuse_inode(inode);
1612
1613 mapping_set_error(inode->i_mapping, req->out.h.error);
1614 spin_lock(&fi->lock);
1615 while (req->misc.write.next) {
1616 struct fuse_conn *fc = get_fuse_conn(inode);
1617 struct fuse_write_in *inarg = &req->misc.write.in;
1618 struct fuse_req *next = req->misc.write.next;
1619 req->misc.write.next = next->misc.write.next;
1620 next->misc.write.next = NULL;
1621 next->ff = fuse_file_get(req->ff);
1622 list_add(&next->writepages_entry, &fi->writepages);
1623
1624 /*
1625 * Skip fuse_flush_writepages() to make it easy to crop requests
1626 * based on primary request size.
1627 *
1628 * 1st case (trivial): there are no concurrent activities using
1629 * fuse_set/release_nowrite. Then we're on safe side because
1630 * fuse_flush_writepages() would call fuse_send_writepage()
1631 * anyway.
1632 *
1633 * 2nd case: someone called fuse_set_nowrite and it is waiting
1634 * now for completion of all in-flight requests. This happens
1635 * rarely and no more than once per page, so this should be
1636 * okay.
1637 *
1638 * 3rd case: someone (e.g. fuse_do_setattr()) is in the middle
1639 * of fuse_set_nowrite..fuse_release_nowrite section. The fact
1640 * that fuse_set_nowrite returned implies that all in-flight
1641 * requests were completed along with all of their secondary
1642 * requests. Further primary requests are blocked by negative
1643 * writectr. Hence there cannot be any in-flight requests and
1644 * no invocations of fuse_writepage_end() while we're in
1645 * fuse_set_nowrite..fuse_release_nowrite section.
1646 */
1647 fuse_send_writepage(fc, next, inarg->offset + inarg->size);
1648 }
1649 fi->writectr--;
1650 fuse_writepage_finish(fc, req);
1651 spin_unlock(&fi->lock);
1652 fuse_writepage_free(fc, req);
1653 }
1654
1655 static struct fuse_file *__fuse_write_file_get(struct fuse_conn *fc,
1656 struct fuse_inode *fi)
1657 {
1658 struct fuse_file *ff = NULL;
1659
1660 spin_lock(&fi->lock);
1661 if (!list_empty(&fi->write_files)) {
1662 ff = list_entry(fi->write_files.next, struct fuse_file,
1663 write_entry);
1664 fuse_file_get(ff);
1665 }
1666 spin_unlock(&fi->lock);
1667
1668 return ff;
1669 }
1670
1671 static struct fuse_file *fuse_write_file_get(struct fuse_conn *fc,
1672 struct fuse_inode *fi)
1673 {
1674 struct fuse_file *ff = __fuse_write_file_get(fc, fi);
1675 WARN_ON(!ff);
1676 return ff;
1677 }
1678
1679 int fuse_write_inode(struct inode *inode, struct writeback_control *wbc)
1680 {
1681 struct fuse_conn *fc = get_fuse_conn(inode);
1682 struct fuse_inode *fi = get_fuse_inode(inode);
1683 struct fuse_file *ff;
1684 int err;
1685
1686 ff = __fuse_write_file_get(fc, fi);
1687 err = fuse_flush_times(inode, ff);
1688 if (ff)
1689 fuse_file_put(ff, false, false);
1690
1691 return err;
1692 }
1693
1694 static int fuse_writepage_locked(struct page *page)
1695 {
1696 struct address_space *mapping = page->mapping;
1697 struct inode *inode = mapping->host;
1698 struct fuse_conn *fc = get_fuse_conn(inode);
1699 struct fuse_inode *fi = get_fuse_inode(inode);
1700 struct fuse_req *req;
1701 struct page *tmp_page;
1702 int error = -ENOMEM;
1703
1704 set_page_writeback(page);
1705
1706 req = fuse_request_alloc_nofs(1);
1707 if (!req)
1708 goto err;
1709
1710 /* writeback always goes to bg_queue */
1711 __set_bit(FR_BACKGROUND, &req->flags);
1712 tmp_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
1713 if (!tmp_page)
1714 goto err_free;
1715
1716 error = -EIO;
1717 req->ff = fuse_write_file_get(fc, fi);
1718 if (!req->ff)
1719 goto err_nofile;
1720
1721 fuse_write_fill(req, req->ff, page_offset(page), 0);
1722
1723 copy_highpage(tmp_page, page);
1724 req->misc.write.in.write_flags |= FUSE_WRITE_CACHE;
1725 req->misc.write.next = NULL;
1726 req->in.argpages = 1;
1727 req->num_pages = 1;
1728 req->pages[0] = tmp_page;
1729 req->page_descs[0].offset = 0;
1730 req->page_descs[0].length = PAGE_SIZE;
1731 req->end = fuse_writepage_end;
1732 req->inode = inode;
1733
1734 inc_wb_stat(&inode_to_bdi(inode)->wb, WB_WRITEBACK);
1735 inc_node_page_state(tmp_page, NR_WRITEBACK_TEMP);
1736
1737 spin_lock(&fi->lock);
1738 list_add(&req->writepages_entry, &fi->writepages);
1739 list_add_tail(&req->list, &fi->queued_writes);
1740 fuse_flush_writepages(inode);
1741 spin_unlock(&fi->lock);
1742
1743 end_page_writeback(page);
1744
1745 return 0;
1746
1747 err_nofile:
1748 __free_page(tmp_page);
1749 err_free:
1750 fuse_request_free(req);
1751 err:
1752 mapping_set_error(page->mapping, error);
1753 end_page_writeback(page);
1754 return error;
1755 }
1756
1757 static int fuse_writepage(struct page *page, struct writeback_control *wbc)
1758 {
1759 int err;
1760
1761 if (fuse_page_is_writeback(page->mapping->host, page->index)) {
1762 /*
1763 * ->writepages() should be called for sync() and friends. We
1764 * should only get here on direct reclaim and then we are
1765 * allowed to skip a page which is already in flight
1766 */
1767 WARN_ON(wbc->sync_mode == WB_SYNC_ALL);
1768
1769 redirty_page_for_writepage(wbc, page);
1770 unlock_page(page);
1771 return 0;
1772 }
1773
1774 err = fuse_writepage_locked(page);
1775 unlock_page(page);
1776
1777 return err;
1778 }
1779
1780 struct fuse_fill_wb_data {
1781 struct fuse_req *req;
1782 struct fuse_file *ff;
1783 struct inode *inode;
1784 struct page **orig_pages;
1785 };
1786
1787 static void fuse_writepages_send(struct fuse_fill_wb_data *data)
1788 {
1789 struct fuse_req *req = data->req;
1790 struct inode *inode = data->inode;
1791 struct fuse_inode *fi = get_fuse_inode(inode);
1792 int num_pages = req->num_pages;
1793 int i;
1794
1795 req->ff = fuse_file_get(data->ff);
1796 spin_lock(&fi->lock);
1797 list_add_tail(&req->list, &fi->queued_writes);
1798 fuse_flush_writepages(inode);
1799 spin_unlock(&fi->lock);
1800
1801 for (i = 0; i < num_pages; i++)
1802 end_page_writeback(data->orig_pages[i]);
1803 }
1804
1805 /*
1806 * First recheck under fi->lock if the offending offset is still under
1807 * writeback. If yes, then iterate auxiliary write requests, to see if there's
1808 * one already added for a page at this offset. If there's none, then insert
1809 * this new request onto the auxiliary list, otherwise reuse the existing one by
1810 * copying the new page contents over to the old temporary page.
1811 */
1812 static bool fuse_writepage_in_flight(struct fuse_req *new_req,
1813 struct page *page)
1814 {
1815 struct fuse_conn *fc = get_fuse_conn(new_req->inode);
1816 struct fuse_inode *fi = get_fuse_inode(new_req->inode);
1817 struct fuse_req *tmp;
1818 struct fuse_req *old_req;
1819
1820 WARN_ON(new_req->num_pages != 0);
1821
1822 spin_lock(&fi->lock);
1823 list_del(&new_req->writepages_entry);
1824 old_req = fuse_find_writeback(fi, page->index, page->index);
1825 if (!old_req) {
1826 list_add(&new_req->writepages_entry, &fi->writepages);
1827 spin_unlock(&fi->lock);
1828 return false;
1829 }
1830
1831 new_req->num_pages = 1;
1832 for (tmp = old_req->misc.write.next; tmp; tmp = tmp->misc.write.next) {
1833 pgoff_t curr_index;
1834
1835 WARN_ON(tmp->inode != new_req->inode);
1836 curr_index = tmp->misc.write.in.offset >> PAGE_SHIFT;
1837 if (curr_index == page->index) {
1838 WARN_ON(tmp->num_pages != 1);
1839 WARN_ON(!test_bit(FR_PENDING, &tmp->flags));
1840 swap(tmp->pages[0], new_req->pages[0]);
1841 break;
1842 }
1843 }
1844
1845 if (!tmp) {
1846 new_req->misc.write.next = old_req->misc.write.next;
1847 old_req->misc.write.next = new_req;
1848 }
1849
1850 spin_unlock(&fi->lock);
1851
1852 if (tmp) {
1853 struct backing_dev_info *bdi = inode_to_bdi(new_req->inode);
1854
1855 dec_wb_stat(&bdi->wb, WB_WRITEBACK);
1856 dec_node_page_state(new_req->pages[0], NR_WRITEBACK_TEMP);
1857 wb_writeout_inc(&bdi->wb);
1858 fuse_writepage_free(fc, new_req);
1859 fuse_request_free(new_req);
1860 }
1861
1862 return true;
1863 }
1864
1865 static int fuse_writepages_fill(struct page *page,
1866 struct writeback_control *wbc, void *_data)
1867 {
1868 struct fuse_fill_wb_data *data = _data;
1869 struct fuse_req *req = data->req;
1870 struct inode *inode = data->inode;
1871 struct fuse_inode *fi = get_fuse_inode(inode);
1872 struct fuse_conn *fc = get_fuse_conn(inode);
1873 struct page *tmp_page;
1874 bool is_writeback;
1875 int err;
1876
1877 if (!data->ff) {
1878 err = -EIO;
1879 data->ff = fuse_write_file_get(fc, get_fuse_inode(inode));
1880 if (!data->ff)
1881 goto out_unlock;
1882 }
1883
1884 /*
1885 * Being under writeback is unlikely but possible. For example direct
1886 * read to an mmaped fuse file will set the page dirty twice; once when
1887 * the pages are faulted with get_user_pages(), and then after the read
1888 * completed.
1889 */
1890 is_writeback = fuse_page_is_writeback(inode, page->index);
1891
1892 if (req && req->num_pages &&
1893 (is_writeback || req->num_pages == fc->max_pages ||
1894 (req->num_pages + 1) * PAGE_SIZE > fc->max_write ||
1895 data->orig_pages[req->num_pages - 1]->index + 1 != page->index)) {
1896 fuse_writepages_send(data);
1897 data->req = NULL;
1898 } else if (req && req->num_pages == req->max_pages) {
1899 if (!fuse_req_realloc_pages(fc, req, GFP_NOFS)) {
1900 fuse_writepages_send(data);
1901 req = data->req = NULL;
1902 }
1903 }
1904
1905 err = -ENOMEM;
1906 tmp_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
1907 if (!tmp_page)
1908 goto out_unlock;
1909
1910 /*
1911 * The page must not be redirtied until the writeout is completed
1912 * (i.e. userspace has sent a reply to the write request). Otherwise
1913 * there could be more than one temporary page instance for each real
1914 * page.
1915 *
1916 * This is ensured by holding the page lock in page_mkwrite() while
1917 * checking fuse_page_is_writeback(). We already hold the page lock
1918 * since clear_page_dirty_for_io() and keep it held until we add the
1919 * request to the fi->writepages list and increment req->num_pages.
1920 * After this fuse_page_is_writeback() will indicate that the page is
1921 * under writeback, so we can release the page lock.
1922 */
1923 if (data->req == NULL) {
1924 struct fuse_inode *fi = get_fuse_inode(inode);
1925
1926 err = -ENOMEM;
1927 req = fuse_request_alloc_nofs(FUSE_REQ_INLINE_PAGES);
1928 if (!req) {
1929 __free_page(tmp_page);
1930 goto out_unlock;
1931 }
1932
1933 fuse_write_fill(req, data->ff, page_offset(page), 0);
1934 req->misc.write.in.write_flags |= FUSE_WRITE_CACHE;
1935 req->misc.write.next = NULL;
1936 req->in.argpages = 1;
1937 __set_bit(FR_BACKGROUND, &req->flags);
1938 req->num_pages = 0;
1939 req->end = fuse_writepage_end;
1940 req->inode = inode;
1941
1942 spin_lock(&fi->lock);
1943 list_add(&req->writepages_entry, &fi->writepages);
1944 spin_unlock(&fi->lock);
1945
1946 data->req = req;
1947 }
1948 set_page_writeback(page);
1949
1950 copy_highpage(tmp_page, page);
1951 req->pages[req->num_pages] = tmp_page;
1952 req->page_descs[req->num_pages].offset = 0;
1953 req->page_descs[req->num_pages].length = PAGE_SIZE;
1954
1955 inc_wb_stat(&inode_to_bdi(inode)->wb, WB_WRITEBACK);
1956 inc_node_page_state(tmp_page, NR_WRITEBACK_TEMP);
1957
1958 err = 0;
1959 if (is_writeback && fuse_writepage_in_flight(req, page)) {
1960 end_page_writeback(page);
1961 data->req = NULL;
1962 goto out_unlock;
1963 }
1964 data->orig_pages[req->num_pages] = page;
1965
1966 /*
1967 * Protected by fi->lock against concurrent access by
1968 * fuse_page_is_writeback().
1969 */
1970 spin_lock(&fi->lock);
1971 req->num_pages++;
1972 spin_unlock(&fi->lock);
1973
1974 out_unlock:
1975 unlock_page(page);
1976
1977 return err;
1978 }
1979
1980 static int fuse_writepages(struct address_space *mapping,
1981 struct writeback_control *wbc)
1982 {
1983 struct inode *inode = mapping->host;
1984 struct fuse_conn *fc = get_fuse_conn(inode);
1985 struct fuse_fill_wb_data data;
1986 int err;
1987
1988 err = -EIO;
1989 if (is_bad_inode(inode))
1990 goto out;
1991
1992 data.inode = inode;
1993 data.req = NULL;
1994 data.ff = NULL;
1995
1996 err = -ENOMEM;
1997 data.orig_pages = kcalloc(fc->max_pages,
1998 sizeof(struct page *),
1999 GFP_NOFS);
2000 if (!data.orig_pages)
2001 goto out;
2002
2003 err = write_cache_pages(mapping, wbc, fuse_writepages_fill, &data);
2004 if (data.req) {
2005 /* Ignore errors if we can write at least one page */
2006 BUG_ON(!data.req->num_pages);
2007 fuse_writepages_send(&data);
2008 err = 0;
2009 }
2010 if (data.ff)
2011 fuse_file_put(data.ff, false, false);
2012
2013 kfree(data.orig_pages);
2014 out:
2015 return err;
2016 }
2017
2018 /*
2019 * It's worthy to make sure that space is reserved on disk for the write,
2020 * but how to implement it without killing performance need more thinking.
2021 */
2022 static int fuse_write_begin(struct file *file, struct address_space *mapping,
2023 loff_t pos, unsigned len, unsigned flags,
2024 struct page **pagep, void **fsdata)
2025 {
2026 pgoff_t index = pos >> PAGE_SHIFT;
2027 struct fuse_conn *fc = get_fuse_conn(file_inode(file));
2028 struct page *page;
2029 loff_t fsize;
2030 int err = -ENOMEM;
2031
2032 WARN_ON(!fc->writeback_cache);
2033
2034 page = grab_cache_page_write_begin(mapping, index, flags);
2035 if (!page)
2036 goto error;
2037
2038 fuse_wait_on_page_writeback(mapping->host, page->index);
2039
2040 if (PageUptodate(page) || len == PAGE_SIZE)
2041 goto success;
2042 /*
2043 * Check if the start this page comes after the end of file, in which
2044 * case the readpage can be optimized away.
2045 */
2046 fsize = i_size_read(mapping->host);
2047 if (fsize <= (pos & PAGE_MASK)) {
2048 size_t off = pos & ~PAGE_MASK;
2049 if (off)
2050 zero_user_segment(page, 0, off);
2051 goto success;
2052 }
2053 err = fuse_do_readpage(file, page);
2054 if (err)
2055 goto cleanup;
2056 success:
2057 *pagep = page;
2058 return 0;
2059
2060 cleanup:
2061 unlock_page(page);
2062 put_page(page);
2063 error:
2064 return err;
2065 }
2066
2067 static int fuse_write_end(struct file *file, struct address_space *mapping,
2068 loff_t pos, unsigned len, unsigned copied,
2069 struct page *page, void *fsdata)
2070 {
2071 struct inode *inode = page->mapping->host;
2072
2073 /* Haven't copied anything? Skip zeroing, size extending, dirtying. */
2074 if (!copied)
2075 goto unlock;
2076
2077 if (!PageUptodate(page)) {
2078 /* Zero any unwritten bytes at the end of the page */
2079 size_t endoff = (pos + copied) & ~PAGE_MASK;
2080 if (endoff)
2081 zero_user_segment(page, endoff, PAGE_SIZE);
2082 SetPageUptodate(page);
2083 }
2084
2085 fuse_write_update_size(inode, pos + copied);
2086 set_page_dirty(page);
2087
2088 unlock:
2089 unlock_page(page);
2090 put_page(page);
2091
2092 return copied;
2093 }
2094
2095 static int fuse_launder_page(struct page *page)
2096 {
2097 int err = 0;
2098 if (clear_page_dirty_for_io(page)) {
2099 struct inode *inode = page->mapping->host;
2100 err = fuse_writepage_locked(page);
2101 if (!err)
2102 fuse_wait_on_page_writeback(inode, page->index);
2103 }
2104 return err;
2105 }
2106
2107 /*
2108 * Write back dirty pages now, because there may not be any suitable
2109 * open files later
2110 */
2111 static void fuse_vma_close(struct vm_area_struct *vma)
2112 {
2113 filemap_write_and_wait(vma->vm_file->f_mapping);
2114 }
2115
2116 /*
2117 * Wait for writeback against this page to complete before allowing it
2118 * to be marked dirty again, and hence written back again, possibly
2119 * before the previous writepage completed.
2120 *
2121 * Block here, instead of in ->writepage(), so that the userspace fs
2122 * can only block processes actually operating on the filesystem.
2123 *
2124 * Otherwise unprivileged userspace fs would be able to block
2125 * unrelated:
2126 *
2127 * - page migration
2128 * - sync(2)
2129 * - try_to_free_pages() with order > PAGE_ALLOC_COSTLY_ORDER
2130 */
2131 static vm_fault_t fuse_page_mkwrite(struct vm_fault *vmf)
2132 {
2133 struct page *page = vmf->page;
2134 struct inode *inode = file_inode(vmf->vma->vm_file);
2135
2136 file_update_time(vmf->vma->vm_file);
2137 lock_page(page);
2138 if (page->mapping != inode->i_mapping) {
2139 unlock_page(page);
2140 return VM_FAULT_NOPAGE;
2141 }
2142
2143 fuse_wait_on_page_writeback(inode, page->index);
2144 return VM_FAULT_LOCKED;
2145 }
2146
2147 static const struct vm_operations_struct fuse_file_vm_ops = {
2148 .close = fuse_vma_close,
2149 .fault = filemap_fault,
2150 .map_pages = filemap_map_pages,
2151 .page_mkwrite = fuse_page_mkwrite,
2152 };
2153
2154 static int fuse_file_mmap(struct file *file, struct vm_area_struct *vma)
2155 {
2156 struct fuse_file *ff = file->private_data;
2157
2158 if (ff->open_flags & FOPEN_DIRECT_IO) {
2159 /* Can't provide the coherency needed for MAP_SHARED */
2160 if (vma->vm_flags & VM_MAYSHARE)
2161 return -ENODEV;
2162
2163 invalidate_inode_pages2(file->f_mapping);
2164
2165 return generic_file_mmap(file, vma);
2166 }
2167
2168 if ((vma->vm_flags & VM_SHARED) && (vma->vm_flags & VM_MAYWRITE))
2169 fuse_link_write_file(file);
2170
2171 file_accessed(file);
2172 vma->vm_ops = &fuse_file_vm_ops;
2173 return 0;
2174 }
2175
2176 static int convert_fuse_file_lock(struct fuse_conn *fc,
2177 const struct fuse_file_lock *ffl,
2178 struct file_lock *fl)
2179 {
2180 switch (ffl->type) {
2181 case F_UNLCK:
2182 break;
2183
2184 case F_RDLCK:
2185 case F_WRLCK:
2186 if (ffl->start > OFFSET_MAX || ffl->end > OFFSET_MAX ||
2187 ffl->end < ffl->start)
2188 return -EIO;
2189
2190 fl->fl_start = ffl->start;
2191 fl->fl_end = ffl->end;
2192
2193 /*
2194 * Convert pid into init's pid namespace. The locks API will
2195 * translate it into the caller's pid namespace.
2196 */
2197 rcu_read_lock();
2198 fl->fl_pid = pid_nr_ns(find_pid_ns(ffl->pid, fc->pid_ns), &init_pid_ns);
2199 rcu_read_unlock();
2200 break;
2201
2202 default:
2203 return -EIO;
2204 }
2205 fl->fl_type = ffl->type;
2206 return 0;
2207 }
2208
2209 static void fuse_lk_fill(struct fuse_args *args, struct file *file,
2210 const struct file_lock *fl, int opcode, pid_t pid,
2211 int flock, struct fuse_lk_in *inarg)
2212 {
2213 struct inode *inode = file_inode(file);
2214 struct fuse_conn *fc = get_fuse_conn(inode);
2215 struct fuse_file *ff = file->private_data;
2216
2217 memset(inarg, 0, sizeof(*inarg));
2218 inarg->fh = ff->fh;
2219 inarg->owner = fuse_lock_owner_id(fc, fl->fl_owner);
2220 inarg->lk.start = fl->fl_start;
2221 inarg->lk.end = fl->fl_end;
2222 inarg->lk.type = fl->fl_type;
2223 inarg->lk.pid = pid;
2224 if (flock)
2225 inarg->lk_flags |= FUSE_LK_FLOCK;
2226 args->in.h.opcode = opcode;
2227 args->in.h.nodeid = get_node_id(inode);
2228 args->in.numargs = 1;
2229 args->in.args[0].size = sizeof(*inarg);
2230 args->in.args[0].value = inarg;
2231 }
2232
2233 static int fuse_getlk(struct file *file, struct file_lock *fl)
2234 {
2235 struct inode *inode = file_inode(file);
2236 struct fuse_conn *fc = get_fuse_conn(inode);
2237 FUSE_ARGS(args);
2238 struct fuse_lk_in inarg;
2239 struct fuse_lk_out outarg;
2240 int err;
2241
2242 fuse_lk_fill(&args, file, fl, FUSE_GETLK, 0, 0, &inarg);
2243 args.out.numargs = 1;
2244 args.out.args[0].size = sizeof(outarg);
2245 args.out.args[0].value = &outarg;
2246 err = fuse_simple_request(fc, &args);
2247 if (!err)
2248 err = convert_fuse_file_lock(fc, &outarg.lk, fl);
2249
2250 return err;
2251 }
2252
2253 static int fuse_setlk(struct file *file, struct file_lock *fl, int flock)
2254 {
2255 struct inode *inode = file_inode(file);
2256 struct fuse_conn *fc = get_fuse_conn(inode);
2257 FUSE_ARGS(args);
2258 struct fuse_lk_in inarg;
2259 int opcode = (fl->fl_flags & FL_SLEEP) ? FUSE_SETLKW : FUSE_SETLK;
2260 struct pid *pid = fl->fl_type != F_UNLCK ? task_tgid(current) : NULL;
2261 pid_t pid_nr = pid_nr_ns(pid, fc->pid_ns);
2262 int err;
2263
2264 if (fl->fl_lmops && fl->fl_lmops->lm_grant) {
2265 /* NLM needs asynchronous locks, which we don't support yet */
2266 return -ENOLCK;
2267 }
2268
2269 /* Unlock on close is handled by the flush method */
2270 if ((fl->fl_flags & FL_CLOSE_POSIX) == FL_CLOSE_POSIX)
2271 return 0;
2272
2273 fuse_lk_fill(&args, file, fl, opcode, pid_nr, flock, &inarg);
2274 err = fuse_simple_request(fc, &args);
2275
2276 /* locking is restartable */
2277 if (err == -EINTR)
2278 err = -ERESTARTSYS;
2279
2280 return err;
2281 }
2282
2283 static int fuse_file_lock(struct file *file, int cmd, struct file_lock *fl)
2284 {
2285 struct inode *inode = file_inode(file);
2286 struct fuse_conn *fc = get_fuse_conn(inode);
2287 int err;
2288
2289 if (cmd == F_CANCELLK) {
2290 err = 0;
2291 } else if (cmd == F_GETLK) {
2292 if (fc->no_lock) {
2293 posix_test_lock(file, fl);
2294 err = 0;
2295 } else
2296 err = fuse_getlk(file, fl);
2297 } else {
2298 if (fc->no_lock)
2299 err = posix_lock_file(file, fl, NULL);
2300 else
2301 err = fuse_setlk(file, fl, 0);
2302 }
2303 return err;
2304 }
2305
2306 static int fuse_file_flock(struct file *file, int cmd, struct file_lock *fl)
2307 {
2308 struct inode *inode = file_inode(file);
2309 struct fuse_conn *fc = get_fuse_conn(inode);
2310 int err;
2311
2312 if (fc->no_flock) {
2313 err = locks_lock_file_wait(file, fl);
2314 } else {
2315 struct fuse_file *ff = file->private_data;
2316
2317 /* emulate flock with POSIX locks */
2318 ff->flock = true;
2319 err = fuse_setlk(file, fl, 1);
2320 }
2321
2322 return err;
2323 }
2324
2325 static sector_t fuse_bmap(struct address_space *mapping, sector_t block)
2326 {
2327 struct inode *inode = mapping->host;
2328 struct fuse_conn *fc = get_fuse_conn(inode);
2329 FUSE_ARGS(args);
2330 struct fuse_bmap_in inarg;
2331 struct fuse_bmap_out outarg;
2332 int err;
2333
2334 if (!inode->i_sb->s_bdev || fc->no_bmap)
2335 return 0;
2336
2337 memset(&inarg, 0, sizeof(inarg));
2338 inarg.block = block;
2339 inarg.blocksize = inode->i_sb->s_blocksize;
2340 args.in.h.opcode = FUSE_BMAP;
2341 args.in.h.nodeid = get_node_id(inode);
2342 args.in.numargs = 1;
2343 args.in.args[0].size = sizeof(inarg);
2344 args.in.args[0].value = &inarg;
2345 args.out.numargs = 1;
2346 args.out.args[0].size = sizeof(outarg);
2347 args.out.args[0].value = &outarg;
2348 err = fuse_simple_request(fc, &args);
2349 if (err == -ENOSYS)
2350 fc->no_bmap = 1;
2351
2352 return err ? 0 : outarg.block;
2353 }
2354
2355 static loff_t fuse_lseek(struct file *file, loff_t offset, int whence)
2356 {
2357 struct inode *inode = file->f_mapping->host;
2358 struct fuse_conn *fc = get_fuse_conn(inode);
2359 struct fuse_file *ff = file->private_data;
2360 FUSE_ARGS(args);
2361 struct fuse_lseek_in inarg = {
2362 .fh = ff->fh,
2363 .offset = offset,
2364 .whence = whence
2365 };
2366 struct fuse_lseek_out outarg;
2367 int err;
2368
2369 if (fc->no_lseek)
2370 goto fallback;
2371
2372 args.in.h.opcode = FUSE_LSEEK;
2373 args.in.h.nodeid = ff->nodeid;
2374 args.in.numargs = 1;
2375 args.in.args[0].size = sizeof(inarg);
2376 args.in.args[0].value = &inarg;
2377 args.out.numargs = 1;
2378 args.out.args[0].size = sizeof(outarg);
2379 args.out.args[0].value = &outarg;
2380 err = fuse_simple_request(fc, &args);
2381 if (err) {
2382 if (err == -ENOSYS) {
2383 fc->no_lseek = 1;
2384 goto fallback;
2385 }
2386 return err;
2387 }
2388
2389 return vfs_setpos(file, outarg.offset, inode->i_sb->s_maxbytes);
2390
2391 fallback:
2392 err = fuse_update_attributes(inode, file);
2393 if (!err)
2394 return generic_file_llseek(file, offset, whence);
2395 else
2396 return err;
2397 }
2398
2399 static loff_t fuse_file_llseek(struct file *file, loff_t offset, int whence)
2400 {
2401 loff_t retval;
2402 struct inode *inode = file_inode(file);
2403
2404 switch (whence) {
2405 case SEEK_SET:
2406 case SEEK_CUR:
2407 /* No i_mutex protection necessary for SEEK_CUR and SEEK_SET */
2408 retval = generic_file_llseek(file, offset, whence);
2409 break;
2410 case SEEK_END:
2411 inode_lock(inode);
2412 retval = fuse_update_attributes(inode, file);
2413 if (!retval)
2414 retval = generic_file_llseek(file, offset, whence);
2415 inode_unlock(inode);
2416 break;
2417 case SEEK_HOLE:
2418 case SEEK_DATA:
2419 inode_lock(inode);
2420 retval = fuse_lseek(file, offset, whence);
2421 inode_unlock(inode);
2422 break;
2423 default:
2424 retval = -EINVAL;
2425 }
2426
2427 return retval;
2428 }
2429
2430 /*
2431 * CUSE servers compiled on 32bit broke on 64bit kernels because the
2432 * ABI was defined to be 'struct iovec' which is different on 32bit
2433 * and 64bit. Fortunately we can determine which structure the server
2434 * used from the size of the reply.
2435 */
2436 static int fuse_copy_ioctl_iovec_old(struct iovec *dst, void *src,
2437 size_t transferred, unsigned count,
2438 bool is_compat)
2439 {
2440 #ifdef CONFIG_COMPAT
2441 if (count * sizeof(struct compat_iovec) == transferred) {
2442 struct compat_iovec *ciov = src;
2443 unsigned i;
2444
2445 /*
2446 * With this interface a 32bit server cannot support
2447 * non-compat (i.e. ones coming from 64bit apps) ioctl
2448 * requests
2449 */
2450 if (!is_compat)
2451 return -EINVAL;
2452
2453 for (i = 0; i < count; i++) {
2454 dst[i].iov_base = compat_ptr(ciov[i].iov_base);
2455 dst[i].iov_len = ciov[i].iov_len;
2456 }
2457 return 0;
2458 }
2459 #endif
2460
2461 if (count * sizeof(struct iovec) != transferred)
2462 return -EIO;
2463
2464 memcpy(dst, src, transferred);
2465 return 0;
2466 }
2467
2468 /* Make sure iov_length() won't overflow */
2469 static int fuse_verify_ioctl_iov(struct fuse_conn *fc, struct iovec *iov,
2470 size_t count)
2471 {
2472 size_t n;
2473 u32 max = fc->max_pages << PAGE_SHIFT;
2474
2475 for (n = 0; n < count; n++, iov++) {
2476 if (iov->iov_len > (size_t) max)
2477 return -ENOMEM;
2478 max -= iov->iov_len;
2479 }
2480 return 0;
2481 }
2482
2483 static int fuse_copy_ioctl_iovec(struct fuse_conn *fc, struct iovec *dst,
2484 void *src, size_t transferred, unsigned count,
2485 bool is_compat)
2486 {
2487 unsigned i;
2488 struct fuse_ioctl_iovec *fiov = src;
2489
2490 if (fc->minor < 16) {
2491 return fuse_copy_ioctl_iovec_old(dst, src, transferred,
2492 count, is_compat);
2493 }
2494
2495 if (count * sizeof(struct fuse_ioctl_iovec) != transferred)
2496 return -EIO;
2497
2498 for (i = 0; i < count; i++) {
2499 /* Did the server supply an inappropriate value? */
2500 if (fiov[i].base != (unsigned long) fiov[i].base ||
2501 fiov[i].len != (unsigned long) fiov[i].len)
2502 return -EIO;
2503
2504 dst[i].iov_base = (void __user *) (unsigned long) fiov[i].base;
2505 dst[i].iov_len = (size_t) fiov[i].len;
2506
2507 #ifdef CONFIG_COMPAT
2508 if (is_compat &&
2509 (ptr_to_compat(dst[i].iov_base) != fiov[i].base ||
2510 (compat_size_t) dst[i].iov_len != fiov[i].len))
2511 return -EIO;
2512 #endif
2513 }
2514
2515 return 0;
2516 }
2517
2518
2519 /*
2520 * For ioctls, there is no generic way to determine how much memory
2521 * needs to be read and/or written. Furthermore, ioctls are allowed
2522 * to dereference the passed pointer, so the parameter requires deep
2523 * copying but FUSE has no idea whatsoever about what to copy in or
2524 * out.
2525 *
2526 * This is solved by allowing FUSE server to retry ioctl with
2527 * necessary in/out iovecs. Let's assume the ioctl implementation
2528 * needs to read in the following structure.
2529 *
2530 * struct a {
2531 * char *buf;
2532 * size_t buflen;
2533 * }
2534 *
2535 * On the first callout to FUSE server, inarg->in_size and
2536 * inarg->out_size will be NULL; then, the server completes the ioctl
2537 * with FUSE_IOCTL_RETRY set in out->flags, out->in_iovs set to 1 and
2538 * the actual iov array to
2539 *
2540 * { { .iov_base = inarg.arg, .iov_len = sizeof(struct a) } }
2541 *
2542 * which tells FUSE to copy in the requested area and retry the ioctl.
2543 * On the second round, the server has access to the structure and
2544 * from that it can tell what to look for next, so on the invocation,
2545 * it sets FUSE_IOCTL_RETRY, out->in_iovs to 2 and iov array to
2546 *
2547 * { { .iov_base = inarg.arg, .iov_len = sizeof(struct a) },
2548 * { .iov_base = a.buf, .iov_len = a.buflen } }
2549 *
2550 * FUSE will copy both struct a and the pointed buffer from the
2551 * process doing the ioctl and retry ioctl with both struct a and the
2552 * buffer.
2553 *
2554 * This time, FUSE server has everything it needs and completes ioctl
2555 * without FUSE_IOCTL_RETRY which finishes the ioctl call.
2556 *
2557 * Copying data out works the same way.
2558 *
2559 * Note that if FUSE_IOCTL_UNRESTRICTED is clear, the kernel
2560 * automatically initializes in and out iovs by decoding @cmd with
2561 * _IOC_* macros and the server is not allowed to request RETRY. This
2562 * limits ioctl data transfers to well-formed ioctls and is the forced
2563 * behavior for all FUSE servers.
2564 */
2565 long fuse_do_ioctl(struct file *file, unsigned int cmd, unsigned long arg,
2566 unsigned int flags)
2567 {
2568 struct fuse_file *ff = file->private_data;
2569 struct fuse_conn *fc = ff->fc;
2570 struct fuse_ioctl_in inarg = {
2571 .fh = ff->fh,
2572 .cmd = cmd,
2573 .arg = arg,
2574 .flags = flags
2575 };
2576 struct fuse_ioctl_out outarg;
2577 struct fuse_req *req = NULL;
2578 struct page **pages = NULL;
2579 struct iovec *iov_page = NULL;
2580 struct iovec *in_iov = NULL, *out_iov = NULL;
2581 unsigned int in_iovs = 0, out_iovs = 0, num_pages = 0, max_pages;
2582 size_t in_size, out_size, transferred, c;
2583 int err, i;
2584 struct iov_iter ii;
2585
2586 #if BITS_PER_LONG == 32
2587 inarg.flags |= FUSE_IOCTL_32BIT;
2588 #else
2589 if (flags & FUSE_IOCTL_COMPAT) {
2590 inarg.flags |= FUSE_IOCTL_32BIT;
2591 #ifdef CONFIG_X86_X32
2592 if (in_x32_syscall())
2593 inarg.flags |= FUSE_IOCTL_COMPAT_X32;
2594 #endif
2595 }
2596 #endif
2597
2598 /* assume all the iovs returned by client always fits in a page */
2599 BUILD_BUG_ON(sizeof(struct fuse_ioctl_iovec) * FUSE_IOCTL_MAX_IOV > PAGE_SIZE);
2600
2601 err = -ENOMEM;
2602 pages = kcalloc(fc->max_pages, sizeof(pages[0]), GFP_KERNEL);
2603 iov_page = (struct iovec *) __get_free_page(GFP_KERNEL);
2604 if (!pages || !iov_page)
2605 goto out;
2606
2607 /*
2608 * If restricted, initialize IO parameters as encoded in @cmd.
2609 * RETRY from server is not allowed.
2610 */
2611 if (!(flags & FUSE_IOCTL_UNRESTRICTED)) {
2612 struct iovec *iov = iov_page;
2613
2614 iov->iov_base = (void __user *)arg;
2615 iov->iov_len = _IOC_SIZE(cmd);
2616
2617 if (_IOC_DIR(cmd) & _IOC_WRITE) {
2618 in_iov = iov;
2619 in_iovs = 1;
2620 }
2621
2622 if (_IOC_DIR(cmd) & _IOC_READ) {
2623 out_iov = iov;
2624 out_iovs = 1;
2625 }
2626 }
2627
2628 retry:
2629 inarg.in_size = in_size = iov_length(in_iov, in_iovs);
2630 inarg.out_size = out_size = iov_length(out_iov, out_iovs);
2631
2632 /*
2633 * Out data can be used either for actual out data or iovs,
2634 * make sure there always is at least one page.
2635 */
2636 out_size = max_t(size_t, out_size, PAGE_SIZE);
2637 max_pages = DIV_ROUND_UP(max(in_size, out_size), PAGE_SIZE);
2638
2639 /* make sure there are enough buffer pages and init request with them */
2640 err = -ENOMEM;
2641 if (max_pages > fc->max_pages)
2642 goto out;
2643 while (num_pages < max_pages) {
2644 pages[num_pages] = alloc_page(GFP_KERNEL | __GFP_HIGHMEM);
2645 if (!pages[num_pages])
2646 goto out;
2647 num_pages++;
2648 }
2649
2650 req = fuse_get_req(fc, num_pages);
2651 if (IS_ERR(req)) {
2652 err = PTR_ERR(req);
2653 req = NULL;
2654 goto out;
2655 }
2656 memcpy(req->pages, pages, sizeof(req->pages[0]) * num_pages);
2657 req->num_pages = num_pages;
2658 fuse_page_descs_length_init(req, 0, req->num_pages);
2659
2660 /* okay, let's send it to the client */
2661 req->in.h.opcode = FUSE_IOCTL;
2662 req->in.h.nodeid = ff->nodeid;
2663 req->in.numargs = 1;
2664 req->in.args[0].size = sizeof(inarg);
2665 req->in.args[0].value = &inarg;
2666 if (in_size) {
2667 req->in.numargs++;
2668 req->in.args[1].size = in_size;
2669 req->in.argpages = 1;
2670
2671 err = -EFAULT;
2672 iov_iter_init(&ii, WRITE, in_iov, in_iovs, in_size);
2673 for (i = 0; iov_iter_count(&ii) && !WARN_ON(i >= num_pages); i++) {
2674 c = copy_page_from_iter(pages[i], 0, PAGE_SIZE, &ii);
2675 if (c != PAGE_SIZE && iov_iter_count(&ii))
2676 goto out;
2677 }
2678 }
2679
2680 req->out.numargs = 2;
2681 req->out.args[0].size = sizeof(outarg);
2682 req->out.args[0].value = &outarg;
2683 req->out.args[1].size = out_size;
2684 req->out.argpages = 1;
2685 req->out.argvar = 1;
2686
2687 fuse_request_send(fc, req);
2688 err = req->out.h.error;
2689 transferred = req->out.args[1].size;
2690 fuse_put_request(fc, req);
2691 req = NULL;
2692 if (err)
2693 goto out;
2694
2695 /* did it ask for retry? */
2696 if (outarg.flags & FUSE_IOCTL_RETRY) {
2697 void *vaddr;
2698
2699 /* no retry if in restricted mode */
2700 err = -EIO;
2701 if (!(flags & FUSE_IOCTL_UNRESTRICTED))
2702 goto out;
2703
2704 in_iovs = outarg.in_iovs;
2705 out_iovs = outarg.out_iovs;
2706
2707 /*
2708 * Make sure things are in boundary, separate checks
2709 * are to protect against overflow.
2710 */
2711 err = -ENOMEM;
2712 if (in_iovs > FUSE_IOCTL_MAX_IOV ||
2713 out_iovs > FUSE_IOCTL_MAX_IOV ||
2714 in_iovs + out_iovs > FUSE_IOCTL_MAX_IOV)
2715 goto out;
2716
2717 vaddr = kmap_atomic(pages[0]);
2718 err = fuse_copy_ioctl_iovec(fc, iov_page, vaddr,
2719 transferred, in_iovs + out_iovs,
2720 (flags & FUSE_IOCTL_COMPAT) != 0);
2721 kunmap_atomic(vaddr);
2722 if (err)
2723 goto out;
2724
2725 in_iov = iov_page;
2726 out_iov = in_iov + in_iovs;
2727
2728 err = fuse_verify_ioctl_iov(fc, in_iov, in_iovs);
2729 if (err)
2730 goto out;
2731
2732 err = fuse_verify_ioctl_iov(fc, out_iov, out_iovs);
2733 if (err)
2734 goto out;
2735
2736 goto retry;
2737 }
2738
2739 err = -EIO;
2740 if (transferred > inarg.out_size)
2741 goto out;
2742
2743 err = -EFAULT;
2744 iov_iter_init(&ii, READ, out_iov, out_iovs, transferred);
2745 for (i = 0; iov_iter_count(&ii) && !WARN_ON(i >= num_pages); i++) {
2746 c = copy_page_to_iter(pages[i], 0, PAGE_SIZE, &ii);
2747 if (c != PAGE_SIZE && iov_iter_count(&ii))
2748 goto out;
2749 }
2750 err = 0;
2751 out:
2752 if (req)
2753 fuse_put_request(fc, req);
2754 free_page((unsigned long) iov_page);
2755 while (num_pages)
2756 __free_page(pages[--num_pages]);
2757 kfree(pages);
2758
2759 return err ? err : outarg.result;
2760 }
2761 EXPORT_SYMBOL_GPL(fuse_do_ioctl);
2762
2763 long fuse_ioctl_common(struct file *file, unsigned int cmd,
2764 unsigned long arg, unsigned int flags)
2765 {
2766 struct inode *inode = file_inode(file);
2767 struct fuse_conn *fc = get_fuse_conn(inode);
2768
2769 if (!fuse_allow_current_process(fc))
2770 return -EACCES;
2771
2772 if (is_bad_inode(inode))
2773 return -EIO;
2774
2775 return fuse_do_ioctl(file, cmd, arg, flags);
2776 }
2777
2778 static long fuse_file_ioctl(struct file *file, unsigned int cmd,
2779 unsigned long arg)
2780 {
2781 return fuse_ioctl_common(file, cmd, arg, 0);
2782 }
2783
2784 static long fuse_file_compat_ioctl(struct file *file, unsigned int cmd,
2785 unsigned long arg)
2786 {
2787 return fuse_ioctl_common(file, cmd, arg, FUSE_IOCTL_COMPAT);
2788 }
2789
2790 /*
2791 * All files which have been polled are linked to RB tree
2792 * fuse_conn->polled_files which is indexed by kh. Walk the tree and
2793 * find the matching one.
2794 */
2795 static struct rb_node **fuse_find_polled_node(struct fuse_conn *fc, u64 kh,
2796 struct rb_node **parent_out)
2797 {
2798 struct rb_node **link = &fc->polled_files.rb_node;
2799 struct rb_node *last = NULL;
2800
2801 while (*link) {
2802 struct fuse_file *ff;
2803
2804 last = *link;
2805 ff = rb_entry(last, struct fuse_file, polled_node);
2806
2807 if (kh < ff->kh)
2808 link = &last->rb_left;
2809 else if (kh > ff->kh)
2810 link = &last->rb_right;
2811 else
2812 return link;
2813 }
2814
2815 if (parent_out)
2816 *parent_out = last;
2817 return link;
2818 }
2819
2820 /*
2821 * The file is about to be polled. Make sure it's on the polled_files
2822 * RB tree. Note that files once added to the polled_files tree are
2823 * not removed before the file is released. This is because a file
2824 * polled once is likely to be polled again.
2825 */
2826 static void fuse_register_polled_file(struct fuse_conn *fc,
2827 struct fuse_file *ff)
2828 {
2829 spin_lock(&fc->lock);
2830 if (RB_EMPTY_NODE(&ff->polled_node)) {
2831 struct rb_node **link, *uninitialized_var(parent);
2832
2833 link = fuse_find_polled_node(fc, ff->kh, &parent);
2834 BUG_ON(*link);
2835 rb_link_node(&ff->polled_node, parent, link);
2836 rb_insert_color(&ff->polled_node, &fc->polled_files);
2837 }
2838 spin_unlock(&fc->lock);
2839 }
2840
2841 __poll_t fuse_file_poll(struct file *file, poll_table *wait)
2842 {
2843 struct fuse_file *ff = file->private_data;
2844 struct fuse_conn *fc = ff->fc;
2845 struct fuse_poll_in inarg = { .fh = ff->fh, .kh = ff->kh };
2846 struct fuse_poll_out outarg;
2847 FUSE_ARGS(args);
2848 int err;
2849
2850 if (fc->no_poll)
2851 return DEFAULT_POLLMASK;
2852
2853 poll_wait(file, &ff->poll_wait, wait);
2854 inarg.events = mangle_poll(poll_requested_events(wait));
2855
2856 /*
2857 * Ask for notification iff there's someone waiting for it.
2858 * The client may ignore the flag and always notify.
2859 */
2860 if (waitqueue_active(&ff->poll_wait)) {
2861 inarg.flags |= FUSE_POLL_SCHEDULE_NOTIFY;
2862 fuse_register_polled_file(fc, ff);
2863 }
2864
2865 args.in.h.opcode = FUSE_POLL;
2866 args.in.h.nodeid = ff->nodeid;
2867 args.in.numargs = 1;
2868 args.in.args[0].size = sizeof(inarg);
2869 args.in.args[0].value = &inarg;
2870 args.out.numargs = 1;
2871 args.out.args[0].size = sizeof(outarg);
2872 args.out.args[0].value = &outarg;
2873 err = fuse_simple_request(fc, &args);
2874
2875 if (!err)
2876 return demangle_poll(outarg.revents);
2877 if (err == -ENOSYS) {
2878 fc->no_poll = 1;
2879 return DEFAULT_POLLMASK;
2880 }
2881 return EPOLLERR;
2882 }
2883 EXPORT_SYMBOL_GPL(fuse_file_poll);
2884
2885 /*
2886 * This is called from fuse_handle_notify() on FUSE_NOTIFY_POLL and
2887 * wakes up the poll waiters.
2888 */
2889 int fuse_notify_poll_wakeup(struct fuse_conn *fc,
2890 struct fuse_notify_poll_wakeup_out *outarg)
2891 {
2892 u64 kh = outarg->kh;
2893 struct rb_node **link;
2894
2895 spin_lock(&fc->lock);
2896
2897 link = fuse_find_polled_node(fc, kh, NULL);
2898 if (*link) {
2899 struct fuse_file *ff;
2900
2901 ff = rb_entry(*link, struct fuse_file, polled_node);
2902 wake_up_interruptible_sync(&ff->poll_wait);
2903 }
2904
2905 spin_unlock(&fc->lock);
2906 return 0;
2907 }
2908
2909 static void fuse_do_truncate(struct file *file)
2910 {
2911 struct inode *inode = file->f_mapping->host;
2912 struct iattr attr;
2913
2914 attr.ia_valid = ATTR_SIZE;
2915 attr.ia_size = i_size_read(inode);
2916
2917 attr.ia_file = file;
2918 attr.ia_valid |= ATTR_FILE;
2919
2920 fuse_do_setattr(file_dentry(file), &attr, file);
2921 }
2922
2923 static inline loff_t fuse_round_up(struct fuse_conn *fc, loff_t off)
2924 {
2925 return round_up(off, fc->max_pages << PAGE_SHIFT);
2926 }
2927
2928 static ssize_t
2929 fuse_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
2930 {
2931 DECLARE_COMPLETION_ONSTACK(wait);
2932 ssize_t ret = 0;
2933 struct file *file = iocb->ki_filp;
2934 struct fuse_file *ff = file->private_data;
2935 bool async_dio = ff->fc->async_dio;
2936 loff_t pos = 0;
2937 struct inode *inode;
2938 loff_t i_size;
2939 size_t count = iov_iter_count(iter);
2940 loff_t offset = iocb->ki_pos;
2941 struct fuse_io_priv *io;
2942
2943 pos = offset;
2944 inode = file->f_mapping->host;
2945 i_size = i_size_read(inode);
2946
2947 if ((iov_iter_rw(iter) == READ) && (offset > i_size))
2948 return 0;
2949
2950 /* optimization for short read */
2951 if (async_dio && iov_iter_rw(iter) != WRITE && offset + count > i_size) {
2952 if (offset >= i_size)
2953 return 0;
2954 iov_iter_truncate(iter, fuse_round_up(ff->fc, i_size - offset));
2955 count = iov_iter_count(iter);
2956 }
2957
2958 io = kmalloc(sizeof(struct fuse_io_priv), GFP_KERNEL);
2959 if (!io)
2960 return -ENOMEM;
2961 spin_lock_init(&io->lock);
2962 kref_init(&io->refcnt);
2963 io->reqs = 1;
2964 io->bytes = -1;
2965 io->size = 0;
2966 io->offset = offset;
2967 io->write = (iov_iter_rw(iter) == WRITE);
2968 io->err = 0;
2969 /*
2970 * By default, we want to optimize all I/Os with async request
2971 * submission to the client filesystem if supported.
2972 */
2973 io->async = async_dio;
2974 io->iocb = iocb;
2975 io->blocking = is_sync_kiocb(iocb);
2976
2977 /*
2978 * We cannot asynchronously extend the size of a file.
2979 * In such case the aio will behave exactly like sync io.
2980 */
2981 if ((offset + count > i_size) && iov_iter_rw(iter) == WRITE)
2982 io->blocking = true;
2983
2984 if (io->async && io->blocking) {
2985 /*
2986 * Additional reference to keep io around after
2987 * calling fuse_aio_complete()
2988 */
2989 kref_get(&io->refcnt);
2990 io->done = &wait;
2991 }
2992
2993 if (iov_iter_rw(iter) == WRITE) {
2994 ret = fuse_direct_io(io, iter, &pos, FUSE_DIO_WRITE);
2995 fuse_invalidate_attr(inode);
2996 } else {
2997 ret = __fuse_direct_read(io, iter, &pos);
2998 }
2999
3000 if (io->async) {
3001 bool blocking = io->blocking;
3002
3003 fuse_aio_complete(io, ret < 0 ? ret : 0, -1);
3004
3005 /* we have a non-extending, async request, so return */
3006 if (!blocking)
3007 return -EIOCBQUEUED;
3008
3009 wait_for_completion(&wait);
3010 ret = fuse_get_res_by_io(io);
3011 }
3012
3013 kref_put(&io->refcnt, fuse_io_release);
3014
3015 if (iov_iter_rw(iter) == WRITE) {
3016 if (ret > 0)
3017 fuse_write_update_size(inode, pos);
3018 else if (ret < 0 && offset + count > i_size)
3019 fuse_do_truncate(file);
3020 }
3021
3022 return ret;
3023 }
3024
3025 static int fuse_writeback_range(struct inode *inode, loff_t start, loff_t end)
3026 {
3027 int err = filemap_write_and_wait_range(inode->i_mapping, start, end);
3028
3029 if (!err)
3030 fuse_sync_writes(inode);
3031
3032 return err;
3033 }
3034
3035 static long fuse_file_fallocate(struct file *file, int mode, loff_t offset,
3036 loff_t length)
3037 {
3038 struct fuse_file *ff = file->private_data;
3039 struct inode *inode = file_inode(file);
3040 struct fuse_inode *fi = get_fuse_inode(inode);
3041 struct fuse_conn *fc = ff->fc;
3042 FUSE_ARGS(args);
3043 struct fuse_fallocate_in inarg = {
3044 .fh = ff->fh,
3045 .offset = offset,
3046 .length = length,
3047 .mode = mode
3048 };
3049 int err;
3050 bool lock_inode = !(mode & FALLOC_FL_KEEP_SIZE) ||
3051 (mode & FALLOC_FL_PUNCH_HOLE);
3052
3053 if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE))
3054 return -EOPNOTSUPP;
3055
3056 if (fc->no_fallocate)
3057 return -EOPNOTSUPP;
3058
3059 if (lock_inode) {
3060 inode_lock(inode);
3061 if (mode & FALLOC_FL_PUNCH_HOLE) {
3062 loff_t endbyte = offset + length - 1;
3063
3064 err = fuse_writeback_range(inode, offset, endbyte);
3065 if (err)
3066 goto out;
3067 }
3068 }
3069
3070 if (!(mode & FALLOC_FL_KEEP_SIZE) &&
3071 offset + length > i_size_read(inode)) {
3072 err = inode_newsize_ok(inode, offset + length);
3073 if (err)
3074 goto out;
3075 }
3076
3077 if (!(mode & FALLOC_FL_KEEP_SIZE))
3078 set_bit(FUSE_I_SIZE_UNSTABLE, &fi->state);
3079
3080 args.in.h.opcode = FUSE_FALLOCATE;
3081 args.in.h.nodeid = ff->nodeid;
3082 args.in.numargs = 1;
3083 args.in.args[0].size = sizeof(inarg);
3084 args.in.args[0].value = &inarg;
3085 err = fuse_simple_request(fc, &args);
3086 if (err == -ENOSYS) {
3087 fc->no_fallocate = 1;
3088 err = -EOPNOTSUPP;
3089 }
3090 if (err)
3091 goto out;
3092
3093 /* we could have extended the file */
3094 if (!(mode & FALLOC_FL_KEEP_SIZE)) {
3095 bool changed = fuse_write_update_size(inode, offset + length);
3096
3097 if (changed && fc->writeback_cache)
3098 file_update_time(file);
3099 }
3100
3101 if (mode & FALLOC_FL_PUNCH_HOLE)
3102 truncate_pagecache_range(inode, offset, offset + length - 1);
3103
3104 fuse_invalidate_attr(inode);
3105
3106 out:
3107 if (!(mode & FALLOC_FL_KEEP_SIZE))
3108 clear_bit(FUSE_I_SIZE_UNSTABLE, &fi->state);
3109
3110 if (lock_inode)
3111 inode_unlock(inode);
3112
3113 return err;
3114 }
3115
3116 static ssize_t fuse_copy_file_range(struct file *file_in, loff_t pos_in,
3117 struct file *file_out, loff_t pos_out,
3118 size_t len, unsigned int flags)
3119 {
3120 struct fuse_file *ff_in = file_in->private_data;
3121 struct fuse_file *ff_out = file_out->private_data;
3122 struct inode *inode_in = file_inode(file_in);
3123 struct inode *inode_out = file_inode(file_out);
3124 struct fuse_inode *fi_out = get_fuse_inode(inode_out);
3125 struct fuse_conn *fc = ff_in->fc;
3126 FUSE_ARGS(args);
3127 struct fuse_copy_file_range_in inarg = {
3128 .fh_in = ff_in->fh,
3129 .off_in = pos_in,
3130 .nodeid_out = ff_out->nodeid,
3131 .fh_out = ff_out->fh,
3132 .off_out = pos_out,
3133 .len = len,
3134 .flags = flags
3135 };
3136 struct fuse_write_out outarg;
3137 ssize_t err;
3138 /* mark unstable when write-back is not used, and file_out gets
3139 * extended */
3140 bool is_unstable = (!fc->writeback_cache) &&
3141 ((pos_out + len) > inode_out->i_size);
3142
3143 if (fc->no_copy_file_range)
3144 return -EOPNOTSUPP;
3145
3146 if (fc->writeback_cache) {
3147 inode_lock(inode_in);
3148 err = fuse_writeback_range(inode_in, pos_in, pos_in + len);
3149 inode_unlock(inode_in);
3150 if (err)
3151 return err;
3152 }
3153
3154 inode_lock(inode_out);
3155
3156 if (fc->writeback_cache) {
3157 err = fuse_writeback_range(inode_out, pos_out, pos_out + len);
3158 if (err)
3159 goto out;
3160 }
3161
3162 if (is_unstable)
3163 set_bit(FUSE_I_SIZE_UNSTABLE, &fi_out->state);
3164
3165 args.in.h.opcode = FUSE_COPY_FILE_RANGE;
3166 args.in.h.nodeid = ff_in->nodeid;
3167 args.in.numargs = 1;
3168 args.in.args[0].size = sizeof(inarg);
3169 args.in.args[0].value = &inarg;
3170 args.out.numargs = 1;
3171 args.out.args[0].size = sizeof(outarg);
3172 args.out.args[0].value = &outarg;
3173 err = fuse_simple_request(fc, &args);
3174 if (err == -ENOSYS) {
3175 fc->no_copy_file_range = 1;
3176 err = -EOPNOTSUPP;
3177 }
3178 if (err)
3179 goto out;
3180
3181 if (fc->writeback_cache) {
3182 fuse_write_update_size(inode_out, pos_out + outarg.size);
3183 file_update_time(file_out);
3184 }
3185
3186 fuse_invalidate_attr(inode_out);
3187
3188 err = outarg.size;
3189 out:
3190 if (is_unstable)
3191 clear_bit(FUSE_I_SIZE_UNSTABLE, &fi_out->state);
3192
3193 inode_unlock(inode_out);
3194
3195 return err;
3196 }
3197
3198 static const struct file_operations fuse_file_operations = {
3199 .llseek = fuse_file_llseek,
3200 .read_iter = fuse_file_read_iter,
3201 .write_iter = fuse_file_write_iter,
3202 .mmap = fuse_file_mmap,
3203 .open = fuse_open,
3204 .flush = fuse_flush,
3205 .release = fuse_release,
3206 .fsync = fuse_fsync,
3207 .lock = fuse_file_lock,
3208 .flock = fuse_file_flock,
3209 .splice_read = generic_file_splice_read,
3210 .splice_write = iter_file_splice_write,
3211 .unlocked_ioctl = fuse_file_ioctl,
3212 .compat_ioctl = fuse_file_compat_ioctl,
3213 .poll = fuse_file_poll,
3214 .fallocate = fuse_file_fallocate,
3215 .copy_file_range = fuse_copy_file_range,
3216 };
3217
3218 static const struct address_space_operations fuse_file_aops = {
3219 .readpage = fuse_readpage,
3220 .writepage = fuse_writepage,
3221 .writepages = fuse_writepages,
3222 .launder_page = fuse_launder_page,
3223 .readpages = fuse_readpages,
3224 .set_page_dirty = __set_page_dirty_nobuffers,
3225 .bmap = fuse_bmap,
3226 .direct_IO = fuse_direct_IO,
3227 .write_begin = fuse_write_begin,
3228 .write_end = fuse_write_end,
3229 };
3230
3231 void fuse_init_file_inode(struct inode *inode)
3232 {
3233 struct fuse_inode *fi = get_fuse_inode(inode);
3234
3235 inode->i_fop = &fuse_file_operations;
3236 inode->i_data.a_ops = &fuse_file_aops;
3237
3238 INIT_LIST_HEAD(&fi->write_files);
3239 INIT_LIST_HEAD(&fi->queued_writes);
3240 fi->writectr = 0;
3241 init_waitqueue_head(&fi->page_waitq);
3242 INIT_LIST_HEAD(&fi->writepages);
3243 }
3244
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