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