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