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/filter.h>
12 #include <linux/pagemap.h>
13 #include <linux/slab.h>
14 #include <linux/kernel.h>
15 #include <linux/sched.h>
16 #include <linux/sched/signal.h>
17 #include <linux/module.h>
18 #include <linux/swap.h>
19 #include <linux/falloc.h>
20 #include <linux/uio.h>
21 #include <linux/fs.h>
22
fuse_send_open(struct fuse_mount * fm,u64 nodeid,unsigned int open_flags,int opcode,struct fuse_open_out * outargp)23 static int fuse_send_open(struct fuse_mount *fm, u64 nodeid,
24 unsigned int open_flags, int opcode,
25 struct fuse_open_out *outargp)
26 {
27 struct fuse_open_in inarg;
28 FUSE_ARGS(args);
29
30 memset(&inarg, 0, sizeof(inarg));
31 inarg.flags = open_flags & ~(O_CREAT | O_EXCL | O_NOCTTY);
32 if (!fm->fc->atomic_o_trunc)
33 inarg.flags &= ~O_TRUNC;
34
35 if (fm->fc->handle_killpriv_v2 &&
36 (inarg.flags & O_TRUNC) && !capable(CAP_FSETID)) {
37 inarg.open_flags |= FUSE_OPEN_KILL_SUIDGID;
38 }
39
40 args.opcode = opcode;
41 args.nodeid = nodeid;
42 args.in_numargs = 1;
43 args.in_args[0].size = sizeof(inarg);
44 args.in_args[0].value = &inarg;
45 args.out_numargs = 1;
46 args.out_args[0].size = sizeof(*outargp);
47 args.out_args[0].value = outargp;
48
49 return fuse_simple_request(fm, &args);
50 }
51
52 struct fuse_release_args {
53 struct fuse_args args;
54 struct fuse_release_in inarg;
55 struct inode *inode;
56 };
57
fuse_file_alloc(struct fuse_mount * fm)58 struct fuse_file *fuse_file_alloc(struct fuse_mount *fm)
59 {
60 struct fuse_file *ff;
61
62 ff = kzalloc(sizeof(struct fuse_file), GFP_KERNEL_ACCOUNT);
63 if (unlikely(!ff))
64 return NULL;
65
66 ff->fm = fm;
67 ff->release_args = kzalloc(sizeof(*ff->release_args),
68 GFP_KERNEL_ACCOUNT);
69 if (!ff->release_args) {
70 kfree(ff);
71 return NULL;
72 }
73
74 INIT_LIST_HEAD(&ff->write_entry);
75 mutex_init(&ff->readdir.lock);
76 refcount_set(&ff->count, 1);
77 RB_CLEAR_NODE(&ff->polled_node);
78 init_waitqueue_head(&ff->poll_wait);
79
80 ff->kh = atomic64_inc_return(&fm->fc->khctr);
81
82 return ff;
83 }
84
fuse_file_free(struct fuse_file * ff)85 void fuse_file_free(struct fuse_file *ff)
86 {
87 kfree(ff->release_args);
88 mutex_destroy(&ff->readdir.lock);
89 kfree(ff);
90 }
91
fuse_file_get(struct fuse_file * ff)92 static struct fuse_file *fuse_file_get(struct fuse_file *ff)
93 {
94 refcount_inc(&ff->count);
95 return ff;
96 }
97
fuse_release_end(struct fuse_mount * fm,struct fuse_args * args,int error)98 static void fuse_release_end(struct fuse_mount *fm, struct fuse_args *args,
99 int error)
100 {
101 struct fuse_release_args *ra = container_of(args, typeof(*ra), args);
102
103 iput(ra->inode);
104 kfree(ra);
105 }
106
fuse_file_put(struct inode * inode,struct fuse_file * ff,bool sync,bool isdir)107 static void fuse_file_put(struct inode *inode, struct fuse_file *ff,
108 bool sync, bool isdir)
109 {
110 struct fuse_args *args = &ff->release_args->args;
111 #ifdef CONFIG_FUSE_BPF
112 struct fuse_err_ret fer;
113 #endif
114
115 if (!refcount_dec_and_test(&ff->count))
116 return;
117
118 #ifdef CONFIG_FUSE_BPF
119 fer = fuse_bpf_backing(inode, struct fuse_release_in,
120 fuse_release_initialize, fuse_release_backing,
121 fuse_release_finalize,
122 inode, ff);
123 if (fer.ret) {
124 fuse_release_end(ff->fm, args, 0);
125 } else
126 #endif
127 if (isdir ? ff->fm->fc->no_opendir : ff->fm->fc->no_open) {
128 /* Do nothing when client does not implement 'open' */
129 fuse_release_end(ff->fm, args, 0);
130 } else if (sync) {
131 fuse_simple_request(ff->fm, args);
132 fuse_release_end(ff->fm, args, 0);
133 } else {
134 args->end = fuse_release_end;
135 if (fuse_simple_background(ff->fm, args,
136 GFP_KERNEL | __GFP_NOFAIL))
137 fuse_release_end(ff->fm, args, -ENOTCONN);
138 }
139 kfree(ff);
140 }
141
fuse_file_open(struct fuse_mount * fm,u64 nodeid,unsigned int open_flags,bool isdir)142 struct fuse_file *fuse_file_open(struct fuse_mount *fm, u64 nodeid,
143 unsigned int open_flags, bool isdir)
144 {
145 struct fuse_conn *fc = fm->fc;
146 struct fuse_file *ff;
147 int opcode = isdir ? FUSE_OPENDIR : FUSE_OPEN;
148
149 ff = fuse_file_alloc(fm);
150 if (!ff)
151 return ERR_PTR(-ENOMEM);
152
153 ff->fh = 0;
154 /* Default for no-open */
155 ff->open_flags = FOPEN_KEEP_CACHE | (isdir ? FOPEN_CACHE_DIR : 0);
156 if (isdir ? !fc->no_opendir : !fc->no_open) {
157 struct fuse_open_out outarg;
158 int err;
159
160 err = fuse_send_open(fm, nodeid, open_flags, opcode, &outarg);
161 if (!err) {
162 ff->fh = outarg.fh;
163 ff->open_flags = outarg.open_flags;
164 fuse_passthrough_setup(fc, ff, &outarg);
165 } else if (err != -ENOSYS) {
166 fuse_file_free(ff);
167 return ERR_PTR(err);
168 } else {
169 if (isdir)
170 fc->no_opendir = 1;
171 else
172 fc->no_open = 1;
173 }
174 }
175
176 if (isdir)
177 ff->open_flags &= ~FOPEN_DIRECT_IO;
178
179 ff->nodeid = nodeid;
180
181 return ff;
182 }
183
fuse_do_open(struct fuse_mount * fm,u64 nodeid,struct file * file,bool isdir)184 int fuse_do_open(struct fuse_mount *fm, u64 nodeid, struct file *file,
185 bool isdir)
186 {
187 struct fuse_file *ff = fuse_file_open(fm, nodeid, file->f_flags, isdir);
188
189 if (!IS_ERR(ff))
190 file->private_data = ff;
191
192 return PTR_ERR_OR_ZERO(ff);
193 }
194 EXPORT_SYMBOL_GPL(fuse_do_open);
195
fuse_link_write_file(struct file * file)196 static void fuse_link_write_file(struct file *file)
197 {
198 struct inode *inode = file_inode(file);
199 struct fuse_inode *fi = get_fuse_inode(inode);
200 struct fuse_file *ff = file->private_data;
201 /*
202 * file may be written through mmap, so chain it onto the
203 * inodes's write_file list
204 */
205 spin_lock(&fi->lock);
206 if (list_empty(&ff->write_entry))
207 list_add(&ff->write_entry, &fi->write_files);
208 spin_unlock(&fi->lock);
209 }
210
fuse_finish_open(struct inode * inode,struct file * file)211 void fuse_finish_open(struct inode *inode, struct file *file)
212 {
213 struct fuse_file *ff = file->private_data;
214 struct fuse_conn *fc = get_fuse_conn(inode);
215
216 if (ff->open_flags & FOPEN_STREAM)
217 stream_open(inode, file);
218 else if (ff->open_flags & FOPEN_NONSEEKABLE)
219 nonseekable_open(inode, file);
220
221 if (fc->atomic_o_trunc && (file->f_flags & O_TRUNC)) {
222 struct fuse_inode *fi = get_fuse_inode(inode);
223
224 spin_lock(&fi->lock);
225 fi->attr_version = atomic64_inc_return(&fc->attr_version);
226 i_size_write(inode, 0);
227 spin_unlock(&fi->lock);
228 file_update_time(file);
229 fuse_invalidate_attr_mask(inode, FUSE_STATX_MODSIZE);
230 }
231 if ((file->f_mode & FMODE_WRITE) && fc->writeback_cache)
232 fuse_link_write_file(file);
233 }
234
fuse_open_common(struct inode * inode,struct file * file,bool isdir)235 int fuse_open_common(struct inode *inode, struct file *file, bool isdir)
236 {
237 struct fuse_mount *fm = get_fuse_mount(inode);
238 struct fuse_conn *fc = fm->fc;
239 int err;
240 bool is_wb_truncate = (file->f_flags & O_TRUNC) &&
241 fc->atomic_o_trunc &&
242 fc->writeback_cache;
243 bool dax_truncate = (file->f_flags & O_TRUNC) &&
244 fc->atomic_o_trunc && FUSE_IS_DAX(inode);
245
246 if (fuse_is_bad(inode))
247 return -EIO;
248
249 err = generic_file_open(inode, file);
250 if (err)
251 return err;
252
253 #ifdef CONFIG_FUSE_BPF
254 {
255 struct fuse_err_ret fer;
256
257 fer = fuse_bpf_backing(inode, struct fuse_open_io,
258 fuse_open_initialize,
259 fuse_open_backing,
260 fuse_open_finalize,
261 inode, file, isdir);
262 if (fer.ret)
263 return PTR_ERR(fer.result);
264 }
265 #endif
266
267 if (is_wb_truncate || dax_truncate)
268 inode_lock(inode);
269
270 if (dax_truncate) {
271 filemap_invalidate_lock(inode->i_mapping);
272 err = fuse_dax_break_layouts(inode, 0, 0);
273 if (err)
274 goto out_inode_unlock;
275 }
276
277 if (is_wb_truncate || dax_truncate)
278 fuse_set_nowrite(inode);
279
280 err = fuse_do_open(fm, get_node_id(inode), file, isdir);
281 if (!err)
282 fuse_finish_open(inode, file);
283
284 if (is_wb_truncate || dax_truncate)
285 fuse_release_nowrite(inode);
286 if (!err) {
287 struct fuse_file *ff = file->private_data;
288
289 if (fc->atomic_o_trunc && (file->f_flags & O_TRUNC))
290 truncate_pagecache(inode, 0);
291 else if (!(ff->open_flags & FOPEN_KEEP_CACHE))
292 invalidate_inode_pages2(inode->i_mapping);
293 }
294 if (dax_truncate)
295 filemap_invalidate_unlock(inode->i_mapping);
296 out_inode_unlock:
297 if (is_wb_truncate || dax_truncate)
298 inode_unlock(inode);
299
300 return err;
301 }
302
fuse_prepare_release(struct fuse_inode * fi,struct fuse_file * ff,unsigned int flags,int opcode)303 static void fuse_prepare_release(struct fuse_inode *fi, struct fuse_file *ff,
304 unsigned int flags, int opcode)
305 {
306 struct fuse_conn *fc = ff->fm->fc;
307 struct fuse_release_args *ra = ff->release_args;
308
309 /* Inode is NULL on error path of fuse_create_open() */
310 if (likely(fi)) {
311 spin_lock(&fi->lock);
312 list_del(&ff->write_entry);
313 spin_unlock(&fi->lock);
314 }
315 spin_lock(&fc->lock);
316 if (!RB_EMPTY_NODE(&ff->polled_node))
317 rb_erase(&ff->polled_node, &fc->polled_files);
318 spin_unlock(&fc->lock);
319
320 wake_up_interruptible_all(&ff->poll_wait);
321
322 ra->inarg.fh = ff->fh;
323 ra->inarg.flags = flags;
324 ra->args.in_numargs = 1;
325 ra->args.in_args[0].size = sizeof(struct fuse_release_in);
326 ra->args.in_args[0].value = &ra->inarg;
327 ra->args.opcode = opcode;
328 ra->args.nodeid = ff->nodeid;
329 ra->args.force = true;
330 ra->args.nocreds = true;
331 }
332
fuse_file_release(struct inode * inode,struct fuse_file * ff,unsigned int open_flags,fl_owner_t id,bool isdir)333 void fuse_file_release(struct inode *inode, struct fuse_file *ff,
334 unsigned int open_flags, fl_owner_t id, bool isdir)
335 {
336 struct fuse_inode *fi = get_fuse_inode(inode);
337 struct fuse_release_args *ra = ff->release_args;
338 int opcode = isdir ? FUSE_RELEASEDIR : FUSE_RELEASE;
339
340 fuse_passthrough_release(&ff->passthrough);
341
342 fuse_prepare_release(fi, ff, open_flags, opcode);
343
344 if (ff->flock) {
345 ra->inarg.release_flags |= FUSE_RELEASE_FLOCK_UNLOCK;
346 ra->inarg.lock_owner = fuse_lock_owner_id(ff->fm->fc, id);
347 }
348 /* Hold inode until release is finished */
349 ra->inode = igrab(inode);
350
351 /*
352 * Normally this will send the RELEASE request, however if
353 * some asynchronous READ or WRITE requests are outstanding,
354 * the sending will be delayed.
355 *
356 * Make the release synchronous if this is a fuseblk mount,
357 * synchronous RELEASE is allowed (and desirable) in this case
358 * because the server can be trusted not to screw up.
359 */
360 fuse_file_put(ra->inode, ff, ff->fm->fc->destroy, isdir);
361 }
362
fuse_release_common(struct file * file,bool isdir)363 void fuse_release_common(struct file *file, bool isdir)
364 {
365 fuse_file_release(file_inode(file), file->private_data, file->f_flags,
366 (fl_owner_t) file, isdir);
367 }
368
fuse_open(struct inode * inode,struct file * file)369 static int fuse_open(struct inode *inode, struct file *file)
370 {
371 return fuse_open_common(inode, file, false);
372 }
373
fuse_release(struct inode * inode,struct file * file)374 static int fuse_release(struct inode *inode, struct file *file)
375 {
376 struct fuse_conn *fc = get_fuse_conn(inode);
377
378 /*
379 * Dirty pages might remain despite write_inode_now() call from
380 * fuse_flush() due to writes racing with the close.
381 */
382 if (fc->writeback_cache)
383 write_inode_now(inode, 1);
384
385 fuse_release_common(file, false);
386
387 /* return value is ignored by VFS */
388 return 0;
389 }
390
fuse_sync_release(struct fuse_inode * fi,struct fuse_file * ff,unsigned int flags)391 void fuse_sync_release(struct fuse_inode *fi, struct fuse_file *ff,
392 unsigned int flags)
393 {
394 WARN_ON(refcount_read(&ff->count) > 1);
395 fuse_prepare_release(fi, ff, flags, FUSE_RELEASE);
396 /*
397 * iput(NULL) is a no-op and since the refcount is 1 and everything's
398 * synchronous, we are fine with not doing igrab() here"
399 */
400 fuse_file_put(&fi->inode, ff, true, false);
401 }
402 EXPORT_SYMBOL_GPL(fuse_sync_release);
403
404 /*
405 * Scramble the ID space with XTEA, so that the value of the files_struct
406 * pointer is not exposed to userspace.
407 */
fuse_lock_owner_id(struct fuse_conn * fc,fl_owner_t id)408 u64 fuse_lock_owner_id(struct fuse_conn *fc, fl_owner_t id)
409 {
410 u32 *k = fc->scramble_key;
411 u64 v = (unsigned long) id;
412 u32 v0 = v;
413 u32 v1 = v >> 32;
414 u32 sum = 0;
415 int i;
416
417 for (i = 0; i < 32; i++) {
418 v0 += ((v1 << 4 ^ v1 >> 5) + v1) ^ (sum + k[sum & 3]);
419 sum += 0x9E3779B9;
420 v1 += ((v0 << 4 ^ v0 >> 5) + v0) ^ (sum + k[sum>>11 & 3]);
421 }
422
423 return (u64) v0 + ((u64) v1 << 32);
424 }
425
426 struct fuse_writepage_args {
427 struct fuse_io_args ia;
428 struct rb_node writepages_entry;
429 struct list_head queue_entry;
430 struct fuse_writepage_args *next;
431 struct inode *inode;
432 struct fuse_sync_bucket *bucket;
433 };
434
fuse_find_writeback(struct fuse_inode * fi,pgoff_t idx_from,pgoff_t idx_to)435 static struct fuse_writepage_args *fuse_find_writeback(struct fuse_inode *fi,
436 pgoff_t idx_from, pgoff_t idx_to)
437 {
438 struct rb_node *n;
439
440 n = fi->writepages.rb_node;
441
442 while (n) {
443 struct fuse_writepage_args *wpa;
444 pgoff_t curr_index;
445
446 wpa = rb_entry(n, struct fuse_writepage_args, writepages_entry);
447 WARN_ON(get_fuse_inode(wpa->inode) != fi);
448 curr_index = wpa->ia.write.in.offset >> PAGE_SHIFT;
449 if (idx_from >= curr_index + wpa->ia.ap.num_pages)
450 n = n->rb_right;
451 else if (idx_to < curr_index)
452 n = n->rb_left;
453 else
454 return wpa;
455 }
456 return NULL;
457 }
458
459 /*
460 * Check if any page in a range is under writeback
461 *
462 * This is currently done by walking the list of writepage requests
463 * for the inode, which can be pretty inefficient.
464 */
fuse_range_is_writeback(struct inode * inode,pgoff_t idx_from,pgoff_t idx_to)465 static bool fuse_range_is_writeback(struct inode *inode, pgoff_t idx_from,
466 pgoff_t idx_to)
467 {
468 struct fuse_inode *fi = get_fuse_inode(inode);
469 bool found;
470
471 spin_lock(&fi->lock);
472 found = fuse_find_writeback(fi, idx_from, idx_to);
473 spin_unlock(&fi->lock);
474
475 return found;
476 }
477
fuse_page_is_writeback(struct inode * inode,pgoff_t index)478 static inline bool fuse_page_is_writeback(struct inode *inode, pgoff_t index)
479 {
480 return fuse_range_is_writeback(inode, index, index);
481 }
482
483 /*
484 * Wait for page writeback to be completed.
485 *
486 * Since fuse doesn't rely on the VM writeback tracking, this has to
487 * use some other means.
488 */
fuse_wait_on_page_writeback(struct inode * inode,pgoff_t index)489 static void fuse_wait_on_page_writeback(struct inode *inode, pgoff_t index)
490 {
491 struct fuse_inode *fi = get_fuse_inode(inode);
492
493 wait_event(fi->page_waitq, !fuse_page_is_writeback(inode, index));
494 }
495
496 /*
497 * Wait for all pending writepages on the inode to finish.
498 *
499 * This is currently done by blocking further writes with FUSE_NOWRITE
500 * and waiting for all sent writes to complete.
501 *
502 * This must be called under i_mutex, otherwise the FUSE_NOWRITE usage
503 * could conflict with truncation.
504 */
fuse_sync_writes(struct inode * inode)505 static void fuse_sync_writes(struct inode *inode)
506 {
507 fuse_set_nowrite(inode);
508 fuse_release_nowrite(inode);
509 }
510
fuse_flush(struct file * file,fl_owner_t id)511 static int fuse_flush(struct file *file, fl_owner_t id)
512 {
513 struct inode *inode = file_inode(file);
514 struct fuse_mount *fm = get_fuse_mount(inode);
515 struct fuse_file *ff = file->private_data;
516 struct fuse_flush_in inarg;
517 FUSE_ARGS(args);
518 int err;
519
520 #ifdef CONFIG_FUSE_BPF
521 struct fuse_err_ret fer;
522
523 fer = fuse_bpf_backing(file->f_inode, struct fuse_flush_in,
524 fuse_flush_initialize, fuse_flush_backing,
525 fuse_flush_finalize,
526 file, id);
527 if (fer.ret)
528 return PTR_ERR(fer.result);
529 #endif
530
531 if (fuse_is_bad(inode))
532 return -EIO;
533
534 if (ff->open_flags & FOPEN_NOFLUSH && !fm->fc->writeback_cache)
535 return 0;
536
537 err = write_inode_now(inode, 1);
538 if (err)
539 return err;
540
541 inode_lock(inode);
542 fuse_sync_writes(inode);
543 inode_unlock(inode);
544
545 err = filemap_check_errors(file->f_mapping);
546 if (err)
547 return err;
548
549 err = 0;
550 if (fm->fc->no_flush)
551 goto inval_attr_out;
552
553 memset(&inarg, 0, sizeof(inarg));
554 inarg.fh = ff->fh;
555 inarg.lock_owner = fuse_lock_owner_id(fm->fc, id);
556 args.opcode = FUSE_FLUSH;
557 args.nodeid = get_node_id(inode);
558 args.in_numargs = 1;
559 args.in_args[0].size = sizeof(inarg);
560 args.in_args[0].value = &inarg;
561 args.force = true;
562
563 err = fuse_simple_request(fm, &args);
564 if (err == -ENOSYS) {
565 fm->fc->no_flush = 1;
566 err = 0;
567 }
568
569 inval_attr_out:
570 /*
571 * In memory i_blocks is not maintained by fuse, if writeback cache is
572 * enabled, i_blocks from cached attr may not be accurate.
573 */
574 if (!err && fm->fc->writeback_cache)
575 fuse_invalidate_attr_mask(inode, STATX_BLOCKS);
576 return err;
577 }
578
fuse_fsync_common(struct file * file,loff_t start,loff_t end,int datasync,int opcode)579 int fuse_fsync_common(struct file *file, loff_t start, loff_t end,
580 int datasync, int opcode)
581 {
582 struct inode *inode = file->f_mapping->host;
583 struct fuse_mount *fm = get_fuse_mount(inode);
584 struct fuse_file *ff = file->private_data;
585 FUSE_ARGS(args);
586 struct fuse_fsync_in inarg;
587
588 memset(&inarg, 0, sizeof(inarg));
589 inarg.fh = ff->fh;
590 inarg.fsync_flags = datasync ? FUSE_FSYNC_FDATASYNC : 0;
591 args.opcode = opcode;
592 args.nodeid = get_node_id(inode);
593 args.in_numargs = 1;
594 args.in_args[0].size = sizeof(inarg);
595 args.in_args[0].value = &inarg;
596 return fuse_simple_request(fm, &args);
597 }
598
fuse_fsync(struct file * file,loff_t start,loff_t end,int datasync)599 static int fuse_fsync(struct file *file, loff_t start, loff_t end,
600 int datasync)
601 {
602 struct inode *inode = file->f_mapping->host;
603 struct fuse_conn *fc = get_fuse_conn(inode);
604 int err;
605
606 #ifdef CONFIG_FUSE_BPF
607 struct fuse_err_ret fer;
608
609 fer = fuse_bpf_backing(inode, struct fuse_fsync_in,
610 fuse_fsync_initialize, fuse_fsync_backing,
611 fuse_fsync_finalize,
612 file, start, end, datasync);
613 if (fer.ret)
614 return PTR_ERR(fer.result);
615 #endif
616
617 if (fuse_is_bad(inode))
618 return -EIO;
619
620 inode_lock(inode);
621
622 /*
623 * Start writeback against all dirty pages of the inode, then
624 * wait for all outstanding writes, before sending the FSYNC
625 * request.
626 */
627 err = file_write_and_wait_range(file, start, end);
628 if (err)
629 goto out;
630
631 fuse_sync_writes(inode);
632
633 /*
634 * Due to implementation of fuse writeback
635 * file_write_and_wait_range() does not catch errors.
636 * We have to do this directly after fuse_sync_writes()
637 */
638 err = file_check_and_advance_wb_err(file);
639 if (err)
640 goto out;
641
642 err = sync_inode_metadata(inode, 1);
643 if (err)
644 goto out;
645
646 if (fc->no_fsync)
647 goto out;
648
649 err = fuse_fsync_common(file, start, end, datasync, FUSE_FSYNC);
650 if (err == -ENOSYS) {
651 fc->no_fsync = 1;
652 err = 0;
653 }
654 out:
655 inode_unlock(inode);
656
657 return err;
658 }
659
fuse_read_args_fill(struct fuse_io_args * ia,struct file * file,loff_t pos,size_t count,int opcode)660 void fuse_read_args_fill(struct fuse_io_args *ia, struct file *file, loff_t pos,
661 size_t count, int opcode)
662 {
663 struct fuse_file *ff = file->private_data;
664 struct fuse_args *args = &ia->ap.args;
665
666 ia->read.in.fh = ff->fh;
667 ia->read.in.offset = pos;
668 ia->read.in.size = count;
669 ia->read.in.flags = file->f_flags;
670 args->opcode = opcode;
671 args->nodeid = ff->nodeid;
672 args->in_numargs = 1;
673 args->in_args[0].size = sizeof(ia->read.in);
674 args->in_args[0].value = &ia->read.in;
675 args->out_argvar = true;
676 args->out_numargs = 1;
677 args->out_args[0].size = count;
678 }
679
fuse_release_user_pages(struct fuse_args_pages * ap,bool should_dirty)680 static void fuse_release_user_pages(struct fuse_args_pages *ap,
681 bool should_dirty)
682 {
683 unsigned int i;
684
685 for (i = 0; i < ap->num_pages; i++) {
686 if (should_dirty)
687 set_page_dirty_lock(ap->pages[i]);
688 put_page(ap->pages[i]);
689 }
690 }
691
fuse_io_release(struct kref * kref)692 static void fuse_io_release(struct kref *kref)
693 {
694 kfree(container_of(kref, struct fuse_io_priv, refcnt));
695 }
696
fuse_get_res_by_io(struct fuse_io_priv * io)697 static ssize_t fuse_get_res_by_io(struct fuse_io_priv *io)
698 {
699 if (io->err)
700 return io->err;
701
702 if (io->bytes >= 0 && io->write)
703 return -EIO;
704
705 return io->bytes < 0 ? io->size : io->bytes;
706 }
707
708 /**
709 * In case of short read, the caller sets 'pos' to the position of
710 * actual end of fuse request in IO request. Otherwise, if bytes_requested
711 * == bytes_transferred or rw == WRITE, the caller sets 'pos' to -1.
712 *
713 * An example:
714 * User requested DIO read of 64K. It was split into two 32K fuse requests,
715 * both submitted asynchronously. The first of them was ACKed by userspace as
716 * fully completed (req->out.args[0].size == 32K) resulting in pos == -1. The
717 * second request was ACKed as short, e.g. only 1K was read, resulting in
718 * pos == 33K.
719 *
720 * Thus, when all fuse requests are completed, the minimal non-negative 'pos'
721 * will be equal to the length of the longest contiguous fragment of
722 * transferred data starting from the beginning of IO request.
723 */
fuse_aio_complete(struct fuse_io_priv * io,int err,ssize_t pos)724 static void fuse_aio_complete(struct fuse_io_priv *io, int err, ssize_t pos)
725 {
726 int left;
727
728 spin_lock(&io->lock);
729 if (err)
730 io->err = io->err ? : err;
731 else if (pos >= 0 && (io->bytes < 0 || pos < io->bytes))
732 io->bytes = pos;
733
734 left = --io->reqs;
735 if (!left && io->blocking)
736 complete(io->done);
737 spin_unlock(&io->lock);
738
739 if (!left && !io->blocking) {
740 ssize_t res = fuse_get_res_by_io(io);
741
742 if (res >= 0) {
743 struct inode *inode = file_inode(io->iocb->ki_filp);
744 struct fuse_conn *fc = get_fuse_conn(inode);
745 struct fuse_inode *fi = get_fuse_inode(inode);
746
747 spin_lock(&fi->lock);
748 fi->attr_version = atomic64_inc_return(&fc->attr_version);
749 spin_unlock(&fi->lock);
750 }
751
752 io->iocb->ki_complete(io->iocb, res);
753 }
754
755 kref_put(&io->refcnt, fuse_io_release);
756 }
757
fuse_io_alloc(struct fuse_io_priv * io,unsigned int npages)758 static struct fuse_io_args *fuse_io_alloc(struct fuse_io_priv *io,
759 unsigned int npages)
760 {
761 struct fuse_io_args *ia;
762
763 ia = kzalloc(sizeof(*ia), GFP_KERNEL);
764 if (ia) {
765 ia->io = io;
766 ia->ap.pages = fuse_pages_alloc(npages, GFP_KERNEL,
767 &ia->ap.descs);
768 if (!ia->ap.pages) {
769 kfree(ia);
770 ia = NULL;
771 }
772 }
773 return ia;
774 }
775
fuse_io_free(struct fuse_io_args * ia)776 static void fuse_io_free(struct fuse_io_args *ia)
777 {
778 kfree(ia->ap.pages);
779 kfree(ia);
780 }
781
fuse_aio_complete_req(struct fuse_mount * fm,struct fuse_args * args,int err)782 static void fuse_aio_complete_req(struct fuse_mount *fm, struct fuse_args *args,
783 int err)
784 {
785 struct fuse_io_args *ia = container_of(args, typeof(*ia), ap.args);
786 struct fuse_io_priv *io = ia->io;
787 ssize_t pos = -1;
788
789 fuse_release_user_pages(&ia->ap, io->should_dirty);
790
791 if (err) {
792 /* Nothing */
793 } else if (io->write) {
794 if (ia->write.out.size > ia->write.in.size) {
795 err = -EIO;
796 } else if (ia->write.in.size != ia->write.out.size) {
797 pos = ia->write.in.offset - io->offset +
798 ia->write.out.size;
799 }
800 } else {
801 u32 outsize = args->out_args[0].size;
802
803 if (ia->read.in.size != outsize)
804 pos = ia->read.in.offset - io->offset + outsize;
805 }
806
807 fuse_aio_complete(io, err, pos);
808 fuse_io_free(ia);
809 }
810
fuse_async_req_send(struct fuse_mount * fm,struct fuse_io_args * ia,size_t num_bytes)811 static ssize_t fuse_async_req_send(struct fuse_mount *fm,
812 struct fuse_io_args *ia, size_t num_bytes)
813 {
814 ssize_t err;
815 struct fuse_io_priv *io = ia->io;
816
817 spin_lock(&io->lock);
818 kref_get(&io->refcnt);
819 io->size += num_bytes;
820 io->reqs++;
821 spin_unlock(&io->lock);
822
823 ia->ap.args.end = fuse_aio_complete_req;
824 ia->ap.args.may_block = io->should_dirty;
825 err = fuse_simple_background(fm, &ia->ap.args, GFP_KERNEL);
826 if (err)
827 fuse_aio_complete_req(fm, &ia->ap.args, err);
828
829 return num_bytes;
830 }
831
fuse_send_read(struct fuse_io_args * ia,loff_t pos,size_t count,fl_owner_t owner)832 static ssize_t fuse_send_read(struct fuse_io_args *ia, loff_t pos, size_t count,
833 fl_owner_t owner)
834 {
835 struct file *file = ia->io->iocb->ki_filp;
836 struct fuse_file *ff = file->private_data;
837 struct fuse_mount *fm = ff->fm;
838
839 fuse_read_args_fill(ia, file, pos, count, FUSE_READ);
840 if (owner != NULL) {
841 ia->read.in.read_flags |= FUSE_READ_LOCKOWNER;
842 ia->read.in.lock_owner = fuse_lock_owner_id(fm->fc, owner);
843 }
844
845 if (ia->io->async)
846 return fuse_async_req_send(fm, ia, count);
847
848 return fuse_simple_request(fm, &ia->ap.args);
849 }
850
fuse_read_update_size(struct inode * inode,loff_t size,u64 attr_ver)851 static void fuse_read_update_size(struct inode *inode, loff_t size,
852 u64 attr_ver)
853 {
854 struct fuse_conn *fc = get_fuse_conn(inode);
855 struct fuse_inode *fi = get_fuse_inode(inode);
856
857 spin_lock(&fi->lock);
858 if (attr_ver >= fi->attr_version && size < inode->i_size &&
859 !test_bit(FUSE_I_SIZE_UNSTABLE, &fi->state)) {
860 fi->attr_version = atomic64_inc_return(&fc->attr_version);
861 i_size_write(inode, size);
862 }
863 spin_unlock(&fi->lock);
864 }
865
fuse_short_read(struct inode * inode,u64 attr_ver,size_t num_read,struct fuse_args_pages * ap)866 static void fuse_short_read(struct inode *inode, u64 attr_ver, size_t num_read,
867 struct fuse_args_pages *ap)
868 {
869 struct fuse_conn *fc = get_fuse_conn(inode);
870
871 /*
872 * If writeback_cache is enabled, a short read means there's a hole in
873 * the file. Some data after the hole is in page cache, but has not
874 * reached the client fs yet. So the hole is not present there.
875 */
876 if (!fc->writeback_cache) {
877 loff_t pos = page_offset(ap->pages[0]) + num_read;
878 fuse_read_update_size(inode, pos, attr_ver);
879 }
880 }
881
fuse_do_readpage(struct file * file,struct page * page)882 static int fuse_do_readpage(struct file *file, struct page *page)
883 {
884 struct inode *inode = page->mapping->host;
885 struct fuse_mount *fm = get_fuse_mount(inode);
886 loff_t pos = page_offset(page);
887 struct fuse_page_desc desc = { .length = PAGE_SIZE };
888 struct fuse_io_args ia = {
889 .ap.args.page_zeroing = true,
890 .ap.args.out_pages = true,
891 .ap.num_pages = 1,
892 .ap.pages = &page,
893 .ap.descs = &desc,
894 };
895 ssize_t res;
896 u64 attr_ver;
897
898 /*
899 * Page writeback can extend beyond the lifetime of the
900 * page-cache page, so make sure we read a properly synced
901 * page.
902 */
903 fuse_wait_on_page_writeback(inode, page->index);
904
905 attr_ver = fuse_get_attr_version(fm->fc);
906
907 /* Don't overflow end offset */
908 if (pos + (desc.length - 1) == LLONG_MAX)
909 desc.length--;
910
911 fuse_read_args_fill(&ia, file, pos, desc.length, FUSE_READ);
912 res = fuse_simple_request(fm, &ia.ap.args);
913 if (res < 0)
914 return res;
915 /*
916 * Short read means EOF. If file size is larger, truncate it
917 */
918 if (res < desc.length)
919 fuse_short_read(inode, attr_ver, res, &ia.ap);
920
921 SetPageUptodate(page);
922
923 return 0;
924 }
925
fuse_read_folio(struct file * file,struct folio * folio)926 static int fuse_read_folio(struct file *file, struct folio *folio)
927 {
928 struct page *page = &folio->page;
929 struct inode *inode = page->mapping->host;
930 int err;
931
932 err = -EIO;
933 if (fuse_is_bad(inode))
934 goto out;
935
936 err = fuse_do_readpage(file, page);
937 fuse_invalidate_atime(inode);
938 out:
939 unlock_page(page);
940 return err;
941 }
942
fuse_readpages_end(struct fuse_mount * fm,struct fuse_args * args,int err)943 static void fuse_readpages_end(struct fuse_mount *fm, struct fuse_args *args,
944 int err)
945 {
946 int i;
947 struct fuse_io_args *ia = container_of(args, typeof(*ia), ap.args);
948 struct fuse_args_pages *ap = &ia->ap;
949 size_t count = ia->read.in.size;
950 size_t num_read = args->out_args[0].size;
951 struct address_space *mapping = NULL;
952
953 for (i = 0; mapping == NULL && i < ap->num_pages; i++)
954 mapping = ap->pages[i]->mapping;
955
956 if (mapping) {
957 struct inode *inode = mapping->host;
958
959 /*
960 * Short read means EOF. If file size is larger, truncate it
961 */
962 if (!err && num_read < count)
963 fuse_short_read(inode, ia->read.attr_ver, num_read, ap);
964
965 fuse_invalidate_atime(inode);
966 }
967
968 for (i = 0; i < ap->num_pages; i++) {
969 struct page *page = ap->pages[i];
970
971 if (!err)
972 SetPageUptodate(page);
973 else
974 SetPageError(page);
975 unlock_page(page);
976 put_page(page);
977 }
978 if (ia->ff) {
979 WARN_ON(!mapping);
980 fuse_file_put(mapping ? mapping->host : NULL, ia->ff,
981 false, false);
982 }
983
984 fuse_io_free(ia);
985 }
986
fuse_send_readpages(struct fuse_io_args * ia,struct file * file)987 static void fuse_send_readpages(struct fuse_io_args *ia, struct file *file)
988 {
989 struct fuse_file *ff = file->private_data;
990 struct fuse_mount *fm = ff->fm;
991 struct fuse_args_pages *ap = &ia->ap;
992 loff_t pos = page_offset(ap->pages[0]);
993 size_t count = ap->num_pages << PAGE_SHIFT;
994 ssize_t res;
995 int err;
996
997 ap->args.out_pages = true;
998 ap->args.page_zeroing = true;
999 ap->args.page_replace = true;
1000
1001 /* Don't overflow end offset */
1002 if (pos + (count - 1) == LLONG_MAX) {
1003 count--;
1004 ap->descs[ap->num_pages - 1].length--;
1005 }
1006 WARN_ON((loff_t) (pos + count) < 0);
1007
1008 fuse_read_args_fill(ia, file, pos, count, FUSE_READ);
1009 ia->read.attr_ver = fuse_get_attr_version(fm->fc);
1010 if (fm->fc->async_read) {
1011 ia->ff = fuse_file_get(ff);
1012 ap->args.end = fuse_readpages_end;
1013 err = fuse_simple_background(fm, &ap->args, GFP_KERNEL);
1014 if (!err)
1015 return;
1016 } else {
1017 res = fuse_simple_request(fm, &ap->args);
1018 err = res < 0 ? res : 0;
1019 }
1020 fuse_readpages_end(fm, &ap->args, err);
1021 }
1022
fuse_readahead(struct readahead_control * rac)1023 static void fuse_readahead(struct readahead_control *rac)
1024 {
1025 struct inode *inode = rac->mapping->host;
1026 struct fuse_conn *fc = get_fuse_conn(inode);
1027 unsigned int i, max_pages, nr_pages = 0;
1028
1029 #ifdef CONFIG_FUSE_BPF
1030 /*
1031 * Currently no meaningful readahead is possible with fuse-bpf within
1032 * the kernel, so unless the daemon is aware of this file, ignore this
1033 * call.
1034 */
1035 if (!get_fuse_inode(inode)->nodeid)
1036 return;
1037 #endif
1038
1039 if (fuse_is_bad(inode))
1040 return;
1041
1042 max_pages = min_t(unsigned int, fc->max_pages,
1043 fc->max_read / PAGE_SIZE);
1044
1045 for (;;) {
1046 struct fuse_io_args *ia;
1047 struct fuse_args_pages *ap;
1048
1049 if (fc->num_background >= fc->congestion_threshold &&
1050 rac->ra->async_size >= readahead_count(rac))
1051 /*
1052 * Congested and only async pages left, so skip the
1053 * rest.
1054 */
1055 break;
1056
1057 nr_pages = readahead_count(rac) - nr_pages;
1058 if (nr_pages > max_pages)
1059 nr_pages = max_pages;
1060 if (nr_pages == 0)
1061 break;
1062 ia = fuse_io_alloc(NULL, nr_pages);
1063 if (!ia)
1064 return;
1065 ap = &ia->ap;
1066 nr_pages = __readahead_batch(rac, ap->pages, nr_pages);
1067 for (i = 0; i < nr_pages; i++) {
1068 fuse_wait_on_page_writeback(inode,
1069 readahead_index(rac) + i);
1070 ap->descs[i].length = PAGE_SIZE;
1071 }
1072 ap->num_pages = nr_pages;
1073 fuse_send_readpages(ia, rac->file);
1074 }
1075 }
1076
fuse_cache_read_iter(struct kiocb * iocb,struct iov_iter * to)1077 static ssize_t fuse_cache_read_iter(struct kiocb *iocb, struct iov_iter *to)
1078 {
1079 struct inode *inode = iocb->ki_filp->f_mapping->host;
1080 struct fuse_conn *fc = get_fuse_conn(inode);
1081
1082 /*
1083 * In auto invalidate mode, always update attributes on read.
1084 * Otherwise, only update if we attempt to read past EOF (to ensure
1085 * i_size is up to date).
1086 */
1087 if (fc->auto_inval_data ||
1088 (iocb->ki_pos + iov_iter_count(to) > i_size_read(inode))) {
1089 int err;
1090 err = fuse_update_attributes(inode, iocb->ki_filp, STATX_SIZE);
1091 if (err)
1092 return err;
1093 }
1094
1095 return generic_file_read_iter(iocb, to);
1096 }
1097
fuse_write_args_fill(struct fuse_io_args * ia,struct fuse_file * ff,loff_t pos,size_t count)1098 static void fuse_write_args_fill(struct fuse_io_args *ia, struct fuse_file *ff,
1099 loff_t pos, size_t count)
1100 {
1101 struct fuse_args *args = &ia->ap.args;
1102
1103 ia->write.in.fh = ff->fh;
1104 ia->write.in.offset = pos;
1105 ia->write.in.size = count;
1106 args->opcode = FUSE_WRITE;
1107 args->nodeid = ff->nodeid;
1108 args->in_numargs = 2;
1109 if (ff->fm->fc->minor < 9)
1110 args->in_args[0].size = FUSE_COMPAT_WRITE_IN_SIZE;
1111 else
1112 args->in_args[0].size = sizeof(ia->write.in);
1113 args->in_args[0].value = &ia->write.in;
1114 args->in_args[1].size = count;
1115 args->out_numargs = 1;
1116 args->out_args[0].size = sizeof(ia->write.out);
1117 args->out_args[0].value = &ia->write.out;
1118 }
1119
fuse_write_flags(struct kiocb * iocb)1120 static unsigned int fuse_write_flags(struct kiocb *iocb)
1121 {
1122 unsigned int flags = iocb->ki_filp->f_flags;
1123
1124 if (iocb_is_dsync(iocb))
1125 flags |= O_DSYNC;
1126 if (iocb->ki_flags & IOCB_SYNC)
1127 flags |= O_SYNC;
1128
1129 return flags;
1130 }
1131
fuse_send_write(struct fuse_io_args * ia,loff_t pos,size_t count,fl_owner_t owner)1132 static ssize_t fuse_send_write(struct fuse_io_args *ia, loff_t pos,
1133 size_t count, fl_owner_t owner)
1134 {
1135 struct kiocb *iocb = ia->io->iocb;
1136 struct file *file = iocb->ki_filp;
1137 struct fuse_file *ff = file->private_data;
1138 struct fuse_mount *fm = ff->fm;
1139 struct fuse_write_in *inarg = &ia->write.in;
1140 ssize_t err;
1141
1142 fuse_write_args_fill(ia, ff, pos, count);
1143 inarg->flags = fuse_write_flags(iocb);
1144 if (owner != NULL) {
1145 inarg->write_flags |= FUSE_WRITE_LOCKOWNER;
1146 inarg->lock_owner = fuse_lock_owner_id(fm->fc, owner);
1147 }
1148
1149 if (ia->io->async)
1150 return fuse_async_req_send(fm, ia, count);
1151
1152 err = fuse_simple_request(fm, &ia->ap.args);
1153 if (!err && ia->write.out.size > count)
1154 err = -EIO;
1155
1156 return err ?: ia->write.out.size;
1157 }
1158
fuse_write_update_attr(struct inode * inode,loff_t pos,ssize_t written)1159 bool fuse_write_update_attr(struct inode *inode, loff_t pos, ssize_t written)
1160 {
1161 struct fuse_conn *fc = get_fuse_conn(inode);
1162 struct fuse_inode *fi = get_fuse_inode(inode);
1163 bool ret = false;
1164
1165 spin_lock(&fi->lock);
1166 fi->attr_version = atomic64_inc_return(&fc->attr_version);
1167 if (written > 0 && pos > inode->i_size) {
1168 i_size_write(inode, pos);
1169 ret = true;
1170 }
1171 spin_unlock(&fi->lock);
1172
1173 fuse_invalidate_attr_mask(inode, FUSE_STATX_MODSIZE);
1174
1175 return ret;
1176 }
1177
fuse_send_write_pages(struct fuse_io_args * ia,struct kiocb * iocb,struct inode * inode,loff_t pos,size_t count)1178 static ssize_t fuse_send_write_pages(struct fuse_io_args *ia,
1179 struct kiocb *iocb, struct inode *inode,
1180 loff_t pos, size_t count)
1181 {
1182 struct fuse_args_pages *ap = &ia->ap;
1183 struct file *file = iocb->ki_filp;
1184 struct fuse_file *ff = file->private_data;
1185 struct fuse_mount *fm = ff->fm;
1186 unsigned int offset, i;
1187 bool short_write;
1188 int err;
1189
1190 for (i = 0; i < ap->num_pages; i++)
1191 fuse_wait_on_page_writeback(inode, ap->pages[i]->index);
1192
1193 fuse_write_args_fill(ia, ff, pos, count);
1194 ia->write.in.flags = fuse_write_flags(iocb);
1195 if (fm->fc->handle_killpriv_v2 && !capable(CAP_FSETID))
1196 ia->write.in.write_flags |= FUSE_WRITE_KILL_SUIDGID;
1197
1198 err = fuse_simple_request(fm, &ap->args);
1199 if (!err && ia->write.out.size > count)
1200 err = -EIO;
1201
1202 short_write = ia->write.out.size < count;
1203 offset = ap->descs[0].offset;
1204 count = ia->write.out.size;
1205 for (i = 0; i < ap->num_pages; i++) {
1206 struct page *page = ap->pages[i];
1207
1208 if (err) {
1209 ClearPageUptodate(page);
1210 } else {
1211 if (count >= PAGE_SIZE - offset)
1212 count -= PAGE_SIZE - offset;
1213 else {
1214 if (short_write)
1215 ClearPageUptodate(page);
1216 count = 0;
1217 }
1218 offset = 0;
1219 }
1220 if (ia->write.page_locked && (i == ap->num_pages - 1))
1221 unlock_page(page);
1222 put_page(page);
1223 }
1224
1225 return err;
1226 }
1227
fuse_fill_write_pages(struct fuse_io_args * ia,struct address_space * mapping,struct iov_iter * ii,loff_t pos,unsigned int max_pages)1228 static ssize_t fuse_fill_write_pages(struct fuse_io_args *ia,
1229 struct address_space *mapping,
1230 struct iov_iter *ii, loff_t pos,
1231 unsigned int max_pages)
1232 {
1233 struct fuse_args_pages *ap = &ia->ap;
1234 struct fuse_conn *fc = get_fuse_conn(mapping->host);
1235 unsigned offset = pos & (PAGE_SIZE - 1);
1236 size_t count = 0;
1237 int err;
1238
1239 ap->args.in_pages = true;
1240 ap->descs[0].offset = offset;
1241
1242 do {
1243 size_t tmp;
1244 struct page *page;
1245 pgoff_t index = pos >> PAGE_SHIFT;
1246 size_t bytes = min_t(size_t, PAGE_SIZE - offset,
1247 iov_iter_count(ii));
1248
1249 bytes = min_t(size_t, bytes, fc->max_write - count);
1250
1251 again:
1252 err = -EFAULT;
1253 if (fault_in_iov_iter_readable(ii, bytes))
1254 break;
1255
1256 err = -ENOMEM;
1257 page = grab_cache_page_write_begin(mapping, index);
1258 if (!page)
1259 break;
1260
1261 if (mapping_writably_mapped(mapping))
1262 flush_dcache_page(page);
1263
1264 tmp = copy_page_from_iter_atomic(page, offset, bytes, ii);
1265 flush_dcache_page(page);
1266
1267 if (!tmp) {
1268 unlock_page(page);
1269 put_page(page);
1270 goto again;
1271 }
1272
1273 err = 0;
1274 ap->pages[ap->num_pages] = page;
1275 ap->descs[ap->num_pages].length = tmp;
1276 ap->num_pages++;
1277
1278 count += tmp;
1279 pos += tmp;
1280 offset += tmp;
1281 if (offset == PAGE_SIZE)
1282 offset = 0;
1283
1284 /* If we copied full page, mark it uptodate */
1285 if (tmp == PAGE_SIZE)
1286 SetPageUptodate(page);
1287
1288 if (PageUptodate(page)) {
1289 unlock_page(page);
1290 } else {
1291 ia->write.page_locked = true;
1292 break;
1293 }
1294 if (!fc->big_writes)
1295 break;
1296 } while (iov_iter_count(ii) && count < fc->max_write &&
1297 ap->num_pages < max_pages && offset == 0);
1298
1299 return count > 0 ? count : err;
1300 }
1301
fuse_wr_pages(loff_t pos,size_t len,unsigned int max_pages)1302 static inline unsigned int fuse_wr_pages(loff_t pos, size_t len,
1303 unsigned int max_pages)
1304 {
1305 return min_t(unsigned int,
1306 ((pos + len - 1) >> PAGE_SHIFT) -
1307 (pos >> PAGE_SHIFT) + 1,
1308 max_pages);
1309 }
1310
fuse_perform_write(struct kiocb * iocb,struct address_space * mapping,struct iov_iter * ii,loff_t pos)1311 static ssize_t fuse_perform_write(struct kiocb *iocb,
1312 struct address_space *mapping,
1313 struct iov_iter *ii, loff_t pos)
1314 {
1315 struct inode *inode = mapping->host;
1316 struct fuse_conn *fc = get_fuse_conn(inode);
1317 struct fuse_inode *fi = get_fuse_inode(inode);
1318 int err = 0;
1319 ssize_t res = 0;
1320
1321 if (inode->i_size < pos + iov_iter_count(ii))
1322 set_bit(FUSE_I_SIZE_UNSTABLE, &fi->state);
1323
1324 do {
1325 ssize_t count;
1326 struct fuse_io_args ia = {};
1327 struct fuse_args_pages *ap = &ia.ap;
1328 unsigned int nr_pages = fuse_wr_pages(pos, iov_iter_count(ii),
1329 fc->max_pages);
1330
1331 ap->pages = fuse_pages_alloc(nr_pages, GFP_KERNEL, &ap->descs);
1332 if (!ap->pages) {
1333 err = -ENOMEM;
1334 break;
1335 }
1336
1337 count = fuse_fill_write_pages(&ia, mapping, ii, pos, nr_pages);
1338 if (count <= 0) {
1339 err = count;
1340 } else {
1341 err = fuse_send_write_pages(&ia, iocb, inode,
1342 pos, count);
1343 if (!err) {
1344 size_t num_written = ia.write.out.size;
1345
1346 res += num_written;
1347 pos += num_written;
1348
1349 /* break out of the loop on short write */
1350 if (num_written != count)
1351 err = -EIO;
1352 }
1353 }
1354 kfree(ap->pages);
1355 } while (!err && iov_iter_count(ii));
1356
1357 fuse_write_update_attr(inode, pos, res);
1358 clear_bit(FUSE_I_SIZE_UNSTABLE, &fi->state);
1359
1360 return res > 0 ? res : err;
1361 }
1362
fuse_cache_write_iter(struct kiocb * iocb,struct iov_iter * from)1363 static ssize_t fuse_cache_write_iter(struct kiocb *iocb, struct iov_iter *from)
1364 {
1365 struct file *file = iocb->ki_filp;
1366 struct address_space *mapping = file->f_mapping;
1367 ssize_t written = 0;
1368 ssize_t written_buffered = 0;
1369 struct inode *inode = mapping->host;
1370 ssize_t err;
1371 struct fuse_conn *fc = get_fuse_conn(inode);
1372 loff_t endbyte = 0;
1373
1374 if (fc->writeback_cache) {
1375 /* Update size (EOF optimization) and mode (SUID clearing) */
1376 err = fuse_update_attributes(mapping->host, file,
1377 STATX_SIZE | STATX_MODE);
1378 if (err)
1379 return err;
1380
1381 if (fc->handle_killpriv_v2 &&
1382 setattr_should_drop_suidgid(&init_user_ns, file_inode(file))) {
1383 goto writethrough;
1384 }
1385
1386 return generic_file_write_iter(iocb, from);
1387 }
1388
1389 writethrough:
1390 inode_lock(inode);
1391
1392 /* We can write back this queue in page reclaim */
1393 current->backing_dev_info = inode_to_bdi(inode);
1394
1395 err = generic_write_checks(iocb, from);
1396 if (err <= 0)
1397 goto out;
1398
1399 err = file_remove_privs(file);
1400 if (err)
1401 goto out;
1402
1403 err = file_update_time(file);
1404 if (err)
1405 goto out;
1406
1407 if (iocb->ki_flags & IOCB_DIRECT) {
1408 loff_t pos = iocb->ki_pos;
1409 written = generic_file_direct_write(iocb, from);
1410 if (written < 0 || !iov_iter_count(from))
1411 goto out;
1412
1413 pos += written;
1414
1415 written_buffered = fuse_perform_write(iocb, mapping, from, pos);
1416 if (written_buffered < 0) {
1417 err = written_buffered;
1418 goto out;
1419 }
1420 endbyte = pos + written_buffered - 1;
1421
1422 err = filemap_write_and_wait_range(file->f_mapping, pos,
1423 endbyte);
1424 if (err)
1425 goto out;
1426
1427 invalidate_mapping_pages(file->f_mapping,
1428 pos >> PAGE_SHIFT,
1429 endbyte >> PAGE_SHIFT);
1430
1431 written += written_buffered;
1432 iocb->ki_pos = pos + written_buffered;
1433 } else {
1434 written = fuse_perform_write(iocb, mapping, from, iocb->ki_pos);
1435 if (written >= 0)
1436 iocb->ki_pos += written;
1437 }
1438 out:
1439 current->backing_dev_info = NULL;
1440 inode_unlock(inode);
1441 if (written > 0)
1442 written = generic_write_sync(iocb, written);
1443
1444 return written ? written : err;
1445 }
1446
fuse_get_user_addr(const struct iov_iter * ii)1447 static inline unsigned long fuse_get_user_addr(const struct iov_iter *ii)
1448 {
1449 return (unsigned long)ii->iov->iov_base + ii->iov_offset;
1450 }
1451
fuse_get_frag_size(const struct iov_iter * ii,size_t max_size)1452 static inline size_t fuse_get_frag_size(const struct iov_iter *ii,
1453 size_t max_size)
1454 {
1455 return min(iov_iter_single_seg_count(ii), max_size);
1456 }
1457
fuse_get_user_pages(struct fuse_args_pages * ap,struct iov_iter * ii,size_t * nbytesp,int write,unsigned int max_pages)1458 static int fuse_get_user_pages(struct fuse_args_pages *ap, struct iov_iter *ii,
1459 size_t *nbytesp, int write,
1460 unsigned int max_pages)
1461 {
1462 size_t nbytes = 0; /* # bytes already packed in req */
1463 ssize_t ret = 0;
1464
1465 /* Special case for kernel I/O: can copy directly into the buffer */
1466 if (iov_iter_is_kvec(ii)) {
1467 unsigned long user_addr = fuse_get_user_addr(ii);
1468 size_t frag_size = fuse_get_frag_size(ii, *nbytesp);
1469
1470 if (write)
1471 ap->args.in_args[1].value = (void *) user_addr;
1472 else
1473 ap->args.out_args[0].value = (void *) user_addr;
1474
1475 iov_iter_advance(ii, frag_size);
1476 *nbytesp = frag_size;
1477 return 0;
1478 }
1479
1480 while (nbytes < *nbytesp && ap->num_pages < max_pages) {
1481 unsigned npages;
1482 size_t start;
1483 ret = iov_iter_get_pages2(ii, &ap->pages[ap->num_pages],
1484 *nbytesp - nbytes,
1485 max_pages - ap->num_pages,
1486 &start);
1487 if (ret < 0)
1488 break;
1489
1490 nbytes += ret;
1491
1492 ret += start;
1493 npages = DIV_ROUND_UP(ret, PAGE_SIZE);
1494
1495 ap->descs[ap->num_pages].offset = start;
1496 fuse_page_descs_length_init(ap->descs, ap->num_pages, npages);
1497
1498 ap->num_pages += npages;
1499 ap->descs[ap->num_pages - 1].length -=
1500 (PAGE_SIZE - ret) & (PAGE_SIZE - 1);
1501 }
1502
1503 ap->args.user_pages = true;
1504 if (write)
1505 ap->args.in_pages = true;
1506 else
1507 ap->args.out_pages = true;
1508
1509 *nbytesp = nbytes;
1510
1511 return ret < 0 ? ret : 0;
1512 }
1513
fuse_direct_io(struct fuse_io_priv * io,struct iov_iter * iter,loff_t * ppos,int flags)1514 ssize_t fuse_direct_io(struct fuse_io_priv *io, struct iov_iter *iter,
1515 loff_t *ppos, int flags)
1516 {
1517 int write = flags & FUSE_DIO_WRITE;
1518 int cuse = flags & FUSE_DIO_CUSE;
1519 struct file *file = io->iocb->ki_filp;
1520 struct inode *inode = file->f_mapping->host;
1521 struct fuse_file *ff = file->private_data;
1522 struct fuse_conn *fc = ff->fm->fc;
1523 size_t nmax = write ? fc->max_write : fc->max_read;
1524 loff_t pos = *ppos;
1525 size_t count = iov_iter_count(iter);
1526 pgoff_t idx_from = pos >> PAGE_SHIFT;
1527 pgoff_t idx_to = (pos + count - 1) >> PAGE_SHIFT;
1528 ssize_t res = 0;
1529 int err = 0;
1530 struct fuse_io_args *ia;
1531 unsigned int max_pages;
1532
1533 max_pages = iov_iter_npages(iter, fc->max_pages);
1534 ia = fuse_io_alloc(io, max_pages);
1535 if (!ia)
1536 return -ENOMEM;
1537
1538 if (!cuse && fuse_range_is_writeback(inode, idx_from, idx_to)) {
1539 if (!write)
1540 inode_lock(inode);
1541 fuse_sync_writes(inode);
1542 if (!write)
1543 inode_unlock(inode);
1544 }
1545
1546 io->should_dirty = !write && user_backed_iter(iter);
1547 while (count) {
1548 ssize_t nres;
1549 fl_owner_t owner = current->files;
1550 size_t nbytes = min(count, nmax);
1551
1552 err = fuse_get_user_pages(&ia->ap, iter, &nbytes, write,
1553 max_pages);
1554 if (err && !nbytes)
1555 break;
1556
1557 if (write) {
1558 if (!capable(CAP_FSETID))
1559 ia->write.in.write_flags |= FUSE_WRITE_KILL_SUIDGID;
1560
1561 nres = fuse_send_write(ia, pos, nbytes, owner);
1562 } else {
1563 nres = fuse_send_read(ia, pos, nbytes, owner);
1564 }
1565
1566 if (!io->async || nres < 0) {
1567 fuse_release_user_pages(&ia->ap, io->should_dirty);
1568 fuse_io_free(ia);
1569 }
1570 ia = NULL;
1571 if (nres < 0) {
1572 iov_iter_revert(iter, nbytes);
1573 err = nres;
1574 break;
1575 }
1576 WARN_ON(nres > nbytes);
1577
1578 count -= nres;
1579 res += nres;
1580 pos += nres;
1581 if (nres != nbytes) {
1582 iov_iter_revert(iter, nbytes - nres);
1583 break;
1584 }
1585 if (count) {
1586 max_pages = iov_iter_npages(iter, fc->max_pages);
1587 ia = fuse_io_alloc(io, max_pages);
1588 if (!ia)
1589 break;
1590 }
1591 }
1592 if (ia)
1593 fuse_io_free(ia);
1594 if (res > 0)
1595 *ppos = pos;
1596
1597 return res > 0 ? res : err;
1598 }
1599 EXPORT_SYMBOL_GPL(fuse_direct_io);
1600
__fuse_direct_read(struct fuse_io_priv * io,struct iov_iter * iter,loff_t * ppos)1601 static ssize_t __fuse_direct_read(struct fuse_io_priv *io,
1602 struct iov_iter *iter,
1603 loff_t *ppos)
1604 {
1605 ssize_t res;
1606 struct inode *inode = file_inode(io->iocb->ki_filp);
1607
1608 res = fuse_direct_io(io, iter, ppos, 0);
1609
1610 fuse_invalidate_atime(inode);
1611
1612 return res;
1613 }
1614
1615 static ssize_t fuse_direct_IO(struct kiocb *iocb, struct iov_iter *iter);
1616
fuse_direct_read_iter(struct kiocb * iocb,struct iov_iter * to)1617 static ssize_t fuse_direct_read_iter(struct kiocb *iocb, struct iov_iter *to)
1618 {
1619 ssize_t res;
1620
1621 if (!is_sync_kiocb(iocb) && iocb->ki_flags & IOCB_DIRECT) {
1622 res = fuse_direct_IO(iocb, to);
1623 } else {
1624 struct fuse_io_priv io = FUSE_IO_PRIV_SYNC(iocb);
1625
1626 res = __fuse_direct_read(&io, to, &iocb->ki_pos);
1627 }
1628
1629 return res;
1630 }
1631
fuse_direct_write_iter(struct kiocb * iocb,struct iov_iter * from)1632 static ssize_t fuse_direct_write_iter(struct kiocb *iocb, struct iov_iter *from)
1633 {
1634 struct inode *inode = file_inode(iocb->ki_filp);
1635 struct fuse_io_priv io = FUSE_IO_PRIV_SYNC(iocb);
1636 ssize_t res;
1637
1638 /* Don't allow parallel writes to the same file */
1639 inode_lock(inode);
1640 res = generic_write_checks(iocb, from);
1641 if (res > 0) {
1642 if (!is_sync_kiocb(iocb) && iocb->ki_flags & IOCB_DIRECT) {
1643 res = fuse_direct_IO(iocb, from);
1644 } else {
1645 res = fuse_direct_io(&io, from, &iocb->ki_pos,
1646 FUSE_DIO_WRITE);
1647 fuse_write_update_attr(inode, iocb->ki_pos, res);
1648 }
1649 }
1650 inode_unlock(inode);
1651
1652 return res;
1653 }
1654
fuse_file_read_iter(struct kiocb * iocb,struct iov_iter * to)1655 static ssize_t fuse_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
1656 {
1657 struct file *file = iocb->ki_filp;
1658 struct fuse_file *ff = file->private_data;
1659 struct inode *inode = file_inode(file);
1660
1661 if (fuse_is_bad(inode))
1662 return -EIO;
1663
1664 if (FUSE_IS_DAX(inode))
1665 return fuse_dax_read_iter(iocb, to);
1666
1667 #ifdef CONFIG_FUSE_BPF
1668 {
1669 struct fuse_err_ret fer;
1670
1671 fer = fuse_bpf_backing(inode, struct fuse_file_read_iter_io,
1672 fuse_file_read_iter_initialize,
1673 fuse_file_read_iter_backing,
1674 fuse_file_read_iter_finalize,
1675 iocb, to);
1676 if (fer.ret)
1677 return PTR_ERR(fer.result);
1678 }
1679 #endif
1680
1681 if (ff->passthrough.filp)
1682 return fuse_passthrough_read_iter(iocb, to);
1683 else if (!(ff->open_flags & FOPEN_DIRECT_IO))
1684 return fuse_cache_read_iter(iocb, to);
1685 else
1686 return fuse_direct_read_iter(iocb, to);
1687 }
1688
fuse_file_write_iter(struct kiocb * iocb,struct iov_iter * from)1689 static ssize_t fuse_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
1690 {
1691 struct file *file = iocb->ki_filp;
1692 struct fuse_file *ff = file->private_data;
1693 struct inode *inode = file_inode(file);
1694
1695 if (fuse_is_bad(inode))
1696 return -EIO;
1697
1698 if (FUSE_IS_DAX(inode))
1699 return fuse_dax_write_iter(iocb, from);
1700
1701 #ifdef CONFIG_FUSE_BPF
1702 {
1703 struct fuse_err_ret fer;
1704
1705 fer = fuse_bpf_backing(inode, struct fuse_file_write_iter_io,
1706 fuse_file_write_iter_initialize,
1707 fuse_file_write_iter_backing,
1708 fuse_file_write_iter_finalize,
1709 iocb, from);
1710 if (fer.ret)
1711 return PTR_ERR(fer.result);
1712 }
1713 #endif
1714
1715 if (ff->passthrough.filp)
1716 return fuse_passthrough_write_iter(iocb, from);
1717 else if (!(ff->open_flags & FOPEN_DIRECT_IO))
1718 return fuse_cache_write_iter(iocb, from);
1719 else
1720 return fuse_direct_write_iter(iocb, from);
1721 }
1722
fuse_writepage_free(struct fuse_writepage_args * wpa)1723 static void fuse_writepage_free(struct fuse_writepage_args *wpa)
1724 {
1725 struct fuse_args_pages *ap = &wpa->ia.ap;
1726 int i;
1727
1728 if (wpa->bucket)
1729 fuse_sync_bucket_dec(wpa->bucket);
1730
1731 for (i = 0; i < ap->num_pages; i++)
1732 __free_page(ap->pages[i]);
1733
1734 if (wpa->ia.ff)
1735 fuse_file_put(wpa->inode, wpa->ia.ff, false, false);
1736
1737 kfree(ap->pages);
1738 kfree(wpa);
1739 }
1740
fuse_writepage_finish(struct fuse_mount * fm,struct fuse_writepage_args * wpa)1741 static void fuse_writepage_finish(struct fuse_mount *fm,
1742 struct fuse_writepage_args *wpa)
1743 {
1744 struct fuse_args_pages *ap = &wpa->ia.ap;
1745 struct inode *inode = wpa->inode;
1746 struct fuse_inode *fi = get_fuse_inode(inode);
1747 struct backing_dev_info *bdi = inode_to_bdi(inode);
1748 int i;
1749
1750 for (i = 0; i < ap->num_pages; i++) {
1751 dec_wb_stat(&bdi->wb, WB_WRITEBACK);
1752 dec_node_page_state(ap->pages[i], NR_WRITEBACK_TEMP);
1753 wb_writeout_inc(&bdi->wb);
1754 }
1755 wake_up(&fi->page_waitq);
1756 }
1757
1758 /* Called under fi->lock, may release and reacquire it */
fuse_send_writepage(struct fuse_mount * fm,struct fuse_writepage_args * wpa,loff_t size)1759 static void fuse_send_writepage(struct fuse_mount *fm,
1760 struct fuse_writepage_args *wpa, loff_t size)
1761 __releases(fi->lock)
1762 __acquires(fi->lock)
1763 {
1764 struct fuse_writepage_args *aux, *next;
1765 struct fuse_inode *fi = get_fuse_inode(wpa->inode);
1766 struct fuse_write_in *inarg = &wpa->ia.write.in;
1767 struct fuse_args *args = &wpa->ia.ap.args;
1768 __u64 data_size = wpa->ia.ap.num_pages * PAGE_SIZE;
1769 int err;
1770
1771 fi->writectr++;
1772 if (inarg->offset + data_size <= size) {
1773 inarg->size = data_size;
1774 } else if (inarg->offset < size) {
1775 inarg->size = size - inarg->offset;
1776 } else {
1777 /* Got truncated off completely */
1778 goto out_free;
1779 }
1780
1781 args->in_args[1].size = inarg->size;
1782 args->force = true;
1783 args->nocreds = true;
1784
1785 err = fuse_simple_background(fm, args, GFP_ATOMIC);
1786 if (err == -ENOMEM) {
1787 spin_unlock(&fi->lock);
1788 err = fuse_simple_background(fm, args, GFP_NOFS | __GFP_NOFAIL);
1789 spin_lock(&fi->lock);
1790 }
1791
1792 /* Fails on broken connection only */
1793 if (unlikely(err))
1794 goto out_free;
1795
1796 return;
1797
1798 out_free:
1799 fi->writectr--;
1800 rb_erase(&wpa->writepages_entry, &fi->writepages);
1801 fuse_writepage_finish(fm, wpa);
1802 spin_unlock(&fi->lock);
1803
1804 /* After fuse_writepage_finish() aux request list is private */
1805 for (aux = wpa->next; aux; aux = next) {
1806 next = aux->next;
1807 aux->next = NULL;
1808 fuse_writepage_free(aux);
1809 }
1810
1811 fuse_writepage_free(wpa);
1812 spin_lock(&fi->lock);
1813 }
1814
1815 /*
1816 * If fi->writectr is positive (no truncate or fsync going on) send
1817 * all queued writepage requests.
1818 *
1819 * Called with fi->lock
1820 */
fuse_flush_writepages(struct inode * inode)1821 void fuse_flush_writepages(struct inode *inode)
1822 __releases(fi->lock)
1823 __acquires(fi->lock)
1824 {
1825 struct fuse_mount *fm = get_fuse_mount(inode);
1826 struct fuse_inode *fi = get_fuse_inode(inode);
1827 loff_t crop = i_size_read(inode);
1828 struct fuse_writepage_args *wpa;
1829
1830 while (fi->writectr >= 0 && !list_empty(&fi->queued_writes)) {
1831 wpa = list_entry(fi->queued_writes.next,
1832 struct fuse_writepage_args, queue_entry);
1833 list_del_init(&wpa->queue_entry);
1834 fuse_send_writepage(fm, wpa, crop);
1835 }
1836 }
1837
fuse_insert_writeback(struct rb_root * root,struct fuse_writepage_args * wpa)1838 static struct fuse_writepage_args *fuse_insert_writeback(struct rb_root *root,
1839 struct fuse_writepage_args *wpa)
1840 {
1841 pgoff_t idx_from = wpa->ia.write.in.offset >> PAGE_SHIFT;
1842 pgoff_t idx_to = idx_from + wpa->ia.ap.num_pages - 1;
1843 struct rb_node **p = &root->rb_node;
1844 struct rb_node *parent = NULL;
1845
1846 WARN_ON(!wpa->ia.ap.num_pages);
1847 while (*p) {
1848 struct fuse_writepage_args *curr;
1849 pgoff_t curr_index;
1850
1851 parent = *p;
1852 curr = rb_entry(parent, struct fuse_writepage_args,
1853 writepages_entry);
1854 WARN_ON(curr->inode != wpa->inode);
1855 curr_index = curr->ia.write.in.offset >> PAGE_SHIFT;
1856
1857 if (idx_from >= curr_index + curr->ia.ap.num_pages)
1858 p = &(*p)->rb_right;
1859 else if (idx_to < curr_index)
1860 p = &(*p)->rb_left;
1861 else
1862 return curr;
1863 }
1864
1865 rb_link_node(&wpa->writepages_entry, parent, p);
1866 rb_insert_color(&wpa->writepages_entry, root);
1867 return NULL;
1868 }
1869
tree_insert(struct rb_root * root,struct fuse_writepage_args * wpa)1870 static void tree_insert(struct rb_root *root, struct fuse_writepage_args *wpa)
1871 {
1872 WARN_ON(fuse_insert_writeback(root, wpa));
1873 }
1874
fuse_writepage_end(struct fuse_mount * fm,struct fuse_args * args,int error)1875 static void fuse_writepage_end(struct fuse_mount *fm, struct fuse_args *args,
1876 int error)
1877 {
1878 struct fuse_writepage_args *wpa =
1879 container_of(args, typeof(*wpa), ia.ap.args);
1880 struct inode *inode = wpa->inode;
1881 struct fuse_inode *fi = get_fuse_inode(inode);
1882 struct fuse_conn *fc = get_fuse_conn(inode);
1883
1884 mapping_set_error(inode->i_mapping, error);
1885 /*
1886 * A writeback finished and this might have updated mtime/ctime on
1887 * server making local mtime/ctime stale. Hence invalidate attrs.
1888 * Do this only if writeback_cache is not enabled. If writeback_cache
1889 * is enabled, we trust local ctime/mtime.
1890 */
1891 if (!fc->writeback_cache)
1892 fuse_invalidate_attr_mask(inode, FUSE_STATX_MODIFY);
1893 spin_lock(&fi->lock);
1894 rb_erase(&wpa->writepages_entry, &fi->writepages);
1895 while (wpa->next) {
1896 struct fuse_mount *fm = get_fuse_mount(inode);
1897 struct fuse_write_in *inarg = &wpa->ia.write.in;
1898 struct fuse_writepage_args *next = wpa->next;
1899
1900 wpa->next = next->next;
1901 next->next = NULL;
1902 next->ia.ff = fuse_file_get(wpa->ia.ff);
1903 tree_insert(&fi->writepages, next);
1904
1905 /*
1906 * Skip fuse_flush_writepages() to make it easy to crop requests
1907 * based on primary request size.
1908 *
1909 * 1st case (trivial): there are no concurrent activities using
1910 * fuse_set/release_nowrite. Then we're on safe side because
1911 * fuse_flush_writepages() would call fuse_send_writepage()
1912 * anyway.
1913 *
1914 * 2nd case: someone called fuse_set_nowrite and it is waiting
1915 * now for completion of all in-flight requests. This happens
1916 * rarely and no more than once per page, so this should be
1917 * okay.
1918 *
1919 * 3rd case: someone (e.g. fuse_do_setattr()) is in the middle
1920 * of fuse_set_nowrite..fuse_release_nowrite section. The fact
1921 * that fuse_set_nowrite returned implies that all in-flight
1922 * requests were completed along with all of their secondary
1923 * requests. Further primary requests are blocked by negative
1924 * writectr. Hence there cannot be any in-flight requests and
1925 * no invocations of fuse_writepage_end() while we're in
1926 * fuse_set_nowrite..fuse_release_nowrite section.
1927 */
1928 fuse_send_writepage(fm, next, inarg->offset + inarg->size);
1929 }
1930 fi->writectr--;
1931 fuse_writepage_finish(fm, wpa);
1932 spin_unlock(&fi->lock);
1933 fuse_writepage_free(wpa);
1934 }
1935
__fuse_write_file_get(struct fuse_inode * fi)1936 static struct fuse_file *__fuse_write_file_get(struct fuse_inode *fi)
1937 {
1938 struct fuse_file *ff;
1939
1940 spin_lock(&fi->lock);
1941 ff = list_first_entry_or_null(&fi->write_files, struct fuse_file,
1942 write_entry);
1943 if (ff)
1944 fuse_file_get(ff);
1945 spin_unlock(&fi->lock);
1946
1947 return ff;
1948 }
1949
fuse_write_file_get(struct fuse_inode * fi)1950 static struct fuse_file *fuse_write_file_get(struct fuse_inode *fi)
1951 {
1952 struct fuse_file *ff = __fuse_write_file_get(fi);
1953 WARN_ON(!ff);
1954 return ff;
1955 }
1956
fuse_write_inode(struct inode * inode,struct writeback_control * wbc)1957 int fuse_write_inode(struct inode *inode, struct writeback_control *wbc)
1958 {
1959 struct fuse_inode *fi = get_fuse_inode(inode);
1960 struct fuse_file *ff;
1961 int err;
1962
1963 /**
1964 * TODO - fully understand why this is necessary
1965 *
1966 * With fuse-bpf, fsstress fails if rename is enabled without this
1967 *
1968 * We are getting writes here on directory inodes, which do not have an
1969 * initialized file list so crash.
1970 *
1971 * The question is why we are getting those writes
1972 */
1973 if (!S_ISREG(inode->i_mode))
1974 return 0;
1975
1976 /*
1977 * Inode is always written before the last reference is dropped and
1978 * hence this should not be reached from reclaim.
1979 *
1980 * Writing back the inode from reclaim can deadlock if the request
1981 * processing itself needs an allocation. Allocations triggering
1982 * reclaim while serving a request can't be prevented, because it can
1983 * involve any number of unrelated userspace processes.
1984 */
1985 WARN_ON(wbc->for_reclaim);
1986
1987 ff = __fuse_write_file_get(fi);
1988 err = fuse_flush_times(inode, ff);
1989 if (ff)
1990 fuse_file_put(inode, ff, false, false);
1991
1992 return err;
1993 }
1994
fuse_writepage_args_alloc(void)1995 static struct fuse_writepage_args *fuse_writepage_args_alloc(void)
1996 {
1997 struct fuse_writepage_args *wpa;
1998 struct fuse_args_pages *ap;
1999
2000 wpa = kzalloc(sizeof(*wpa), GFP_NOFS);
2001 if (wpa) {
2002 ap = &wpa->ia.ap;
2003 ap->num_pages = 0;
2004 ap->pages = fuse_pages_alloc(1, GFP_NOFS, &ap->descs);
2005 if (!ap->pages) {
2006 kfree(wpa);
2007 wpa = NULL;
2008 }
2009 }
2010 return wpa;
2011
2012 }
2013
fuse_writepage_add_to_bucket(struct fuse_conn * fc,struct fuse_writepage_args * wpa)2014 static void fuse_writepage_add_to_bucket(struct fuse_conn *fc,
2015 struct fuse_writepage_args *wpa)
2016 {
2017 if (!fc->sync_fs)
2018 return;
2019
2020 rcu_read_lock();
2021 /* Prevent resurrection of dead bucket in unlikely race with syncfs */
2022 do {
2023 wpa->bucket = rcu_dereference(fc->curr_bucket);
2024 } while (unlikely(!atomic_inc_not_zero(&wpa->bucket->count)));
2025 rcu_read_unlock();
2026 }
2027
fuse_writepage_locked(struct page * page)2028 static int fuse_writepage_locked(struct page *page)
2029 {
2030 struct address_space *mapping = page->mapping;
2031 struct inode *inode = mapping->host;
2032 struct fuse_conn *fc = get_fuse_conn(inode);
2033 struct fuse_inode *fi = get_fuse_inode(inode);
2034 struct fuse_writepage_args *wpa;
2035 struct fuse_args_pages *ap;
2036 struct page *tmp_page;
2037 int error = -ENOMEM;
2038
2039 set_page_writeback(page);
2040
2041 wpa = fuse_writepage_args_alloc();
2042 if (!wpa)
2043 goto err;
2044 ap = &wpa->ia.ap;
2045
2046 tmp_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
2047 if (!tmp_page)
2048 goto err_free;
2049
2050 error = -EIO;
2051 wpa->ia.ff = fuse_write_file_get(fi);
2052 if (!wpa->ia.ff)
2053 goto err_nofile;
2054
2055 fuse_writepage_add_to_bucket(fc, wpa);
2056 fuse_write_args_fill(&wpa->ia, wpa->ia.ff, page_offset(page), 0);
2057
2058 copy_highpage(tmp_page, page);
2059 wpa->ia.write.in.write_flags |= FUSE_WRITE_CACHE;
2060 wpa->next = NULL;
2061 ap->args.in_pages = true;
2062 ap->num_pages = 1;
2063 ap->pages[0] = tmp_page;
2064 ap->descs[0].offset = 0;
2065 ap->descs[0].length = PAGE_SIZE;
2066 ap->args.end = fuse_writepage_end;
2067 wpa->inode = inode;
2068
2069 inc_wb_stat(&inode_to_bdi(inode)->wb, WB_WRITEBACK);
2070 inc_node_page_state(tmp_page, NR_WRITEBACK_TEMP);
2071
2072 spin_lock(&fi->lock);
2073 tree_insert(&fi->writepages, wpa);
2074 list_add_tail(&wpa->queue_entry, &fi->queued_writes);
2075 fuse_flush_writepages(inode);
2076 spin_unlock(&fi->lock);
2077
2078 end_page_writeback(page);
2079
2080 return 0;
2081
2082 err_nofile:
2083 __free_page(tmp_page);
2084 err_free:
2085 kfree(wpa);
2086 err:
2087 mapping_set_error(page->mapping, error);
2088 end_page_writeback(page);
2089 return error;
2090 }
2091
fuse_writepage(struct page * page,struct writeback_control * wbc)2092 static int fuse_writepage(struct page *page, struct writeback_control *wbc)
2093 {
2094 struct fuse_conn *fc = get_fuse_conn(page->mapping->host);
2095 int err;
2096
2097 if (fuse_page_is_writeback(page->mapping->host, page->index)) {
2098 /*
2099 * ->writepages() should be called for sync() and friends. We
2100 * should only get here on direct reclaim and then we are
2101 * allowed to skip a page which is already in flight
2102 */
2103 WARN_ON(wbc->sync_mode == WB_SYNC_ALL);
2104
2105 redirty_page_for_writepage(wbc, page);
2106 unlock_page(page);
2107 return 0;
2108 }
2109
2110 if (wbc->sync_mode == WB_SYNC_NONE &&
2111 fc->num_background >= fc->congestion_threshold)
2112 return AOP_WRITEPAGE_ACTIVATE;
2113
2114 err = fuse_writepage_locked(page);
2115 unlock_page(page);
2116
2117 return err;
2118 }
2119
2120 struct fuse_fill_wb_data {
2121 struct fuse_writepage_args *wpa;
2122 struct fuse_file *ff;
2123 struct inode *inode;
2124 struct page **orig_pages;
2125 unsigned int max_pages;
2126 };
2127
fuse_pages_realloc(struct fuse_fill_wb_data * data)2128 static bool fuse_pages_realloc(struct fuse_fill_wb_data *data)
2129 {
2130 struct fuse_args_pages *ap = &data->wpa->ia.ap;
2131 struct fuse_conn *fc = get_fuse_conn(data->inode);
2132 struct page **pages;
2133 struct fuse_page_desc *descs;
2134 unsigned int npages = min_t(unsigned int,
2135 max_t(unsigned int, data->max_pages * 2,
2136 FUSE_DEFAULT_MAX_PAGES_PER_REQ),
2137 fc->max_pages);
2138 WARN_ON(npages <= data->max_pages);
2139
2140 pages = fuse_pages_alloc(npages, GFP_NOFS, &descs);
2141 if (!pages)
2142 return false;
2143
2144 memcpy(pages, ap->pages, sizeof(struct page *) * ap->num_pages);
2145 memcpy(descs, ap->descs, sizeof(struct fuse_page_desc) * ap->num_pages);
2146 kfree(ap->pages);
2147 ap->pages = pages;
2148 ap->descs = descs;
2149 data->max_pages = npages;
2150
2151 return true;
2152 }
2153
fuse_writepages_send(struct fuse_fill_wb_data * data)2154 static void fuse_writepages_send(struct fuse_fill_wb_data *data)
2155 {
2156 struct fuse_writepage_args *wpa = data->wpa;
2157 struct inode *inode = data->inode;
2158 struct fuse_inode *fi = get_fuse_inode(inode);
2159 int num_pages = wpa->ia.ap.num_pages;
2160 int i;
2161
2162 wpa->ia.ff = fuse_file_get(data->ff);
2163 spin_lock(&fi->lock);
2164 list_add_tail(&wpa->queue_entry, &fi->queued_writes);
2165 fuse_flush_writepages(inode);
2166 spin_unlock(&fi->lock);
2167
2168 for (i = 0; i < num_pages; i++)
2169 end_page_writeback(data->orig_pages[i]);
2170 }
2171
2172 /*
2173 * Check under fi->lock if the page is under writeback, and insert it onto the
2174 * rb_tree if not. Otherwise iterate auxiliary write requests, to see if there's
2175 * one already added for a page at this offset. If there's none, then insert
2176 * this new request onto the auxiliary list, otherwise reuse the existing one by
2177 * swapping the new temp page with the old one.
2178 */
fuse_writepage_add(struct fuse_writepage_args * new_wpa,struct page * page)2179 static bool fuse_writepage_add(struct fuse_writepage_args *new_wpa,
2180 struct page *page)
2181 {
2182 struct fuse_inode *fi = get_fuse_inode(new_wpa->inode);
2183 struct fuse_writepage_args *tmp;
2184 struct fuse_writepage_args *old_wpa;
2185 struct fuse_args_pages *new_ap = &new_wpa->ia.ap;
2186
2187 WARN_ON(new_ap->num_pages != 0);
2188 new_ap->num_pages = 1;
2189
2190 spin_lock(&fi->lock);
2191 old_wpa = fuse_insert_writeback(&fi->writepages, new_wpa);
2192 if (!old_wpa) {
2193 spin_unlock(&fi->lock);
2194 return true;
2195 }
2196
2197 for (tmp = old_wpa->next; tmp; tmp = tmp->next) {
2198 pgoff_t curr_index;
2199
2200 WARN_ON(tmp->inode != new_wpa->inode);
2201 curr_index = tmp->ia.write.in.offset >> PAGE_SHIFT;
2202 if (curr_index == page->index) {
2203 WARN_ON(tmp->ia.ap.num_pages != 1);
2204 swap(tmp->ia.ap.pages[0], new_ap->pages[0]);
2205 break;
2206 }
2207 }
2208
2209 if (!tmp) {
2210 new_wpa->next = old_wpa->next;
2211 old_wpa->next = new_wpa;
2212 }
2213
2214 spin_unlock(&fi->lock);
2215
2216 if (tmp) {
2217 struct backing_dev_info *bdi = inode_to_bdi(new_wpa->inode);
2218
2219 dec_wb_stat(&bdi->wb, WB_WRITEBACK);
2220 dec_node_page_state(new_ap->pages[0], NR_WRITEBACK_TEMP);
2221 wb_writeout_inc(&bdi->wb);
2222 fuse_writepage_free(new_wpa);
2223 }
2224
2225 return false;
2226 }
2227
fuse_writepage_need_send(struct fuse_conn * fc,struct page * page,struct fuse_args_pages * ap,struct fuse_fill_wb_data * data)2228 static bool fuse_writepage_need_send(struct fuse_conn *fc, struct page *page,
2229 struct fuse_args_pages *ap,
2230 struct fuse_fill_wb_data *data)
2231 {
2232 WARN_ON(!ap->num_pages);
2233
2234 /*
2235 * Being under writeback is unlikely but possible. For example direct
2236 * read to an mmaped fuse file will set the page dirty twice; once when
2237 * the pages are faulted with get_user_pages(), and then after the read
2238 * completed.
2239 */
2240 if (fuse_page_is_writeback(data->inode, page->index))
2241 return true;
2242
2243 /* Reached max pages */
2244 if (ap->num_pages == fc->max_pages)
2245 return true;
2246
2247 /* Reached max write bytes */
2248 if ((ap->num_pages + 1) * PAGE_SIZE > fc->max_write)
2249 return true;
2250
2251 /* Discontinuity */
2252 if (data->orig_pages[ap->num_pages - 1]->index + 1 != page->index)
2253 return true;
2254
2255 /* Need to grow the pages array? If so, did the expansion fail? */
2256 if (ap->num_pages == data->max_pages && !fuse_pages_realloc(data))
2257 return true;
2258
2259 return false;
2260 }
2261
fuse_writepages_fill(struct page * page,struct writeback_control * wbc,void * _data)2262 static int fuse_writepages_fill(struct page *page,
2263 struct writeback_control *wbc, void *_data)
2264 {
2265 struct fuse_fill_wb_data *data = _data;
2266 struct fuse_writepage_args *wpa = data->wpa;
2267 struct fuse_args_pages *ap = &wpa->ia.ap;
2268 struct inode *inode = data->inode;
2269 struct fuse_inode *fi = get_fuse_inode(inode);
2270 struct fuse_conn *fc = get_fuse_conn(inode);
2271 struct page *tmp_page;
2272 int err;
2273
2274 if (!data->ff) {
2275 err = -EIO;
2276 data->ff = fuse_write_file_get(fi);
2277 if (!data->ff)
2278 goto out_unlock;
2279 }
2280
2281 if (wpa && fuse_writepage_need_send(fc, page, ap, data)) {
2282 fuse_writepages_send(data);
2283 data->wpa = NULL;
2284 }
2285
2286 err = -ENOMEM;
2287 tmp_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
2288 if (!tmp_page)
2289 goto out_unlock;
2290
2291 /*
2292 * The page must not be redirtied until the writeout is completed
2293 * (i.e. userspace has sent a reply to the write request). Otherwise
2294 * there could be more than one temporary page instance for each real
2295 * page.
2296 *
2297 * This is ensured by holding the page lock in page_mkwrite() while
2298 * checking fuse_page_is_writeback(). We already hold the page lock
2299 * since clear_page_dirty_for_io() and keep it held until we add the
2300 * request to the fi->writepages list and increment ap->num_pages.
2301 * After this fuse_page_is_writeback() will indicate that the page is
2302 * under writeback, so we can release the page lock.
2303 */
2304 if (data->wpa == NULL) {
2305 err = -ENOMEM;
2306 wpa = fuse_writepage_args_alloc();
2307 if (!wpa) {
2308 __free_page(tmp_page);
2309 goto out_unlock;
2310 }
2311 fuse_writepage_add_to_bucket(fc, wpa);
2312
2313 data->max_pages = 1;
2314
2315 ap = &wpa->ia.ap;
2316 fuse_write_args_fill(&wpa->ia, data->ff, page_offset(page), 0);
2317 wpa->ia.write.in.write_flags |= FUSE_WRITE_CACHE;
2318 wpa->next = NULL;
2319 ap->args.in_pages = true;
2320 ap->args.end = fuse_writepage_end;
2321 ap->num_pages = 0;
2322 wpa->inode = inode;
2323 }
2324 set_page_writeback(page);
2325
2326 copy_highpage(tmp_page, page);
2327 ap->pages[ap->num_pages] = tmp_page;
2328 ap->descs[ap->num_pages].offset = 0;
2329 ap->descs[ap->num_pages].length = PAGE_SIZE;
2330 data->orig_pages[ap->num_pages] = page;
2331
2332 inc_wb_stat(&inode_to_bdi(inode)->wb, WB_WRITEBACK);
2333 inc_node_page_state(tmp_page, NR_WRITEBACK_TEMP);
2334
2335 err = 0;
2336 if (data->wpa) {
2337 /*
2338 * Protected by fi->lock against concurrent access by
2339 * fuse_page_is_writeback().
2340 */
2341 spin_lock(&fi->lock);
2342 ap->num_pages++;
2343 spin_unlock(&fi->lock);
2344 } else if (fuse_writepage_add(wpa, page)) {
2345 data->wpa = wpa;
2346 } else {
2347 end_page_writeback(page);
2348 }
2349 out_unlock:
2350 unlock_page(page);
2351
2352 return err;
2353 }
2354
fuse_writepages(struct address_space * mapping,struct writeback_control * wbc)2355 static int fuse_writepages(struct address_space *mapping,
2356 struct writeback_control *wbc)
2357 {
2358 struct inode *inode = mapping->host;
2359 struct fuse_conn *fc = get_fuse_conn(inode);
2360 struct fuse_fill_wb_data data;
2361 int err;
2362
2363 err = -EIO;
2364 if (fuse_is_bad(inode))
2365 goto out;
2366
2367 if (wbc->sync_mode == WB_SYNC_NONE &&
2368 fc->num_background >= fc->congestion_threshold)
2369 return 0;
2370
2371 data.inode = inode;
2372 data.wpa = NULL;
2373 data.ff = NULL;
2374
2375 err = -ENOMEM;
2376 data.orig_pages = kcalloc(fc->max_pages,
2377 sizeof(struct page *),
2378 GFP_NOFS);
2379 if (!data.orig_pages)
2380 goto out;
2381
2382 err = write_cache_pages(mapping, wbc, fuse_writepages_fill, &data);
2383 if (data.wpa) {
2384 WARN_ON(!data.wpa->ia.ap.num_pages);
2385 fuse_writepages_send(&data);
2386 }
2387 if (data.ff)
2388 fuse_file_put(inode, data.ff, false, false);
2389
2390 kfree(data.orig_pages);
2391 out:
2392 return err;
2393 }
2394
2395 /*
2396 * It's worthy to make sure that space is reserved on disk for the write,
2397 * but how to implement it without killing performance need more thinking.
2398 */
fuse_write_begin(struct file * file,struct address_space * mapping,loff_t pos,unsigned len,struct page ** pagep,void ** fsdata)2399 static int fuse_write_begin(struct file *file, struct address_space *mapping,
2400 loff_t pos, unsigned len, struct page **pagep, void **fsdata)
2401 {
2402 pgoff_t index = pos >> PAGE_SHIFT;
2403 struct fuse_conn *fc = get_fuse_conn(file_inode(file));
2404 struct page *page;
2405 loff_t fsize;
2406 int err = -ENOMEM;
2407
2408 WARN_ON(!fc->writeback_cache);
2409
2410 page = grab_cache_page_write_begin(mapping, index);
2411 if (!page)
2412 goto error;
2413
2414 fuse_wait_on_page_writeback(mapping->host, page->index);
2415
2416 if (PageUptodate(page) || len == PAGE_SIZE)
2417 goto success;
2418 /*
2419 * Check if the start this page comes after the end of file, in which
2420 * case the readpage can be optimized away.
2421 */
2422 fsize = i_size_read(mapping->host);
2423 if (fsize <= (pos & PAGE_MASK)) {
2424 size_t off = pos & ~PAGE_MASK;
2425 if (off)
2426 zero_user_segment(page, 0, off);
2427 goto success;
2428 }
2429 err = fuse_do_readpage(file, page);
2430 if (err)
2431 goto cleanup;
2432 success:
2433 *pagep = page;
2434 return 0;
2435
2436 cleanup:
2437 unlock_page(page);
2438 put_page(page);
2439 error:
2440 return err;
2441 }
2442
fuse_write_end(struct file * file,struct address_space * mapping,loff_t pos,unsigned len,unsigned copied,struct page * page,void * fsdata)2443 static int fuse_write_end(struct file *file, struct address_space *mapping,
2444 loff_t pos, unsigned len, unsigned copied,
2445 struct page *page, void *fsdata)
2446 {
2447 struct inode *inode = page->mapping->host;
2448
2449 /* Haven't copied anything? Skip zeroing, size extending, dirtying. */
2450 if (!copied)
2451 goto unlock;
2452
2453 pos += copied;
2454 if (!PageUptodate(page)) {
2455 /* Zero any unwritten bytes at the end of the page */
2456 size_t endoff = pos & ~PAGE_MASK;
2457 if (endoff)
2458 zero_user_segment(page, endoff, PAGE_SIZE);
2459 SetPageUptodate(page);
2460 }
2461
2462 if (pos > inode->i_size)
2463 i_size_write(inode, pos);
2464
2465 set_page_dirty(page);
2466
2467 unlock:
2468 unlock_page(page);
2469 put_page(page);
2470
2471 return copied;
2472 }
2473
fuse_launder_folio(struct folio * folio)2474 static int fuse_launder_folio(struct folio *folio)
2475 {
2476 int err = 0;
2477 if (folio_clear_dirty_for_io(folio)) {
2478 struct inode *inode = folio->mapping->host;
2479
2480 /* Serialize with pending writeback for the same page */
2481 fuse_wait_on_page_writeback(inode, folio->index);
2482 err = fuse_writepage_locked(&folio->page);
2483 if (!err)
2484 fuse_wait_on_page_writeback(inode, folio->index);
2485 }
2486 return err;
2487 }
2488
2489 /*
2490 * Write back dirty data/metadata now (there may not be any suitable
2491 * open files later for data)
2492 */
fuse_vma_close(struct vm_area_struct * vma)2493 static void fuse_vma_close(struct vm_area_struct *vma)
2494 {
2495 int err;
2496
2497 err = write_inode_now(vma->vm_file->f_mapping->host, 1);
2498 mapping_set_error(vma->vm_file->f_mapping, err);
2499 }
2500
2501 /*
2502 * Wait for writeback against this page to complete before allowing it
2503 * to be marked dirty again, and hence written back again, possibly
2504 * before the previous writepage completed.
2505 *
2506 * Block here, instead of in ->writepage(), so that the userspace fs
2507 * can only block processes actually operating on the filesystem.
2508 *
2509 * Otherwise unprivileged userspace fs would be able to block
2510 * unrelated:
2511 *
2512 * - page migration
2513 * - sync(2)
2514 * - try_to_free_pages() with order > PAGE_ALLOC_COSTLY_ORDER
2515 */
fuse_page_mkwrite(struct vm_fault * vmf)2516 static vm_fault_t fuse_page_mkwrite(struct vm_fault *vmf)
2517 {
2518 struct page *page = vmf->page;
2519 struct inode *inode = file_inode(vmf->vma->vm_file);
2520
2521 file_update_time(vmf->vma->vm_file);
2522 lock_page(page);
2523 if (page->mapping != inode->i_mapping) {
2524 unlock_page(page);
2525 return VM_FAULT_NOPAGE;
2526 }
2527
2528 fuse_wait_on_page_writeback(inode, page->index);
2529 return VM_FAULT_LOCKED;
2530 }
2531
2532 static const struct vm_operations_struct fuse_file_vm_ops = {
2533 .close = fuse_vma_close,
2534 .fault = filemap_fault,
2535 .map_pages = filemap_map_pages,
2536 .page_mkwrite = fuse_page_mkwrite,
2537 };
2538
fuse_file_mmap(struct file * file,struct vm_area_struct * vma)2539 static int fuse_file_mmap(struct file *file, struct vm_area_struct *vma)
2540 {
2541 struct fuse_file *ff = file->private_data;
2542
2543 /* DAX mmap is superior to direct_io mmap */
2544 if (FUSE_IS_DAX(file_inode(file)))
2545 return fuse_dax_mmap(file, vma);
2546
2547 #ifdef CONFIG_FUSE_BPF
2548 /* TODO - this is simply passthrough, not a proper BPF filter */
2549 if (ff->backing_file)
2550 return fuse_backing_mmap(file, vma);
2551 #endif
2552
2553 if (ff->passthrough.filp)
2554 return fuse_passthrough_mmap(file, vma);
2555
2556 if (ff->open_flags & FOPEN_DIRECT_IO) {
2557 /* Can't provide the coherency needed for MAP_SHARED */
2558 if (vma->vm_flags & VM_MAYSHARE)
2559 return -ENODEV;
2560
2561 invalidate_inode_pages2(file->f_mapping);
2562
2563 return generic_file_mmap(file, vma);
2564 }
2565
2566 if ((vma->vm_flags & VM_SHARED) && (vma->vm_flags & VM_MAYWRITE))
2567 fuse_link_write_file(file);
2568
2569 file_accessed(file);
2570 vma->vm_ops = &fuse_file_vm_ops;
2571 return 0;
2572 }
2573
convert_fuse_file_lock(struct fuse_conn * fc,const struct fuse_file_lock * ffl,struct file_lock * fl)2574 static int convert_fuse_file_lock(struct fuse_conn *fc,
2575 const struct fuse_file_lock *ffl,
2576 struct file_lock *fl)
2577 {
2578 switch (ffl->type) {
2579 case F_UNLCK:
2580 break;
2581
2582 case F_RDLCK:
2583 case F_WRLCK:
2584 if (ffl->start > OFFSET_MAX || ffl->end > OFFSET_MAX ||
2585 ffl->end < ffl->start)
2586 return -EIO;
2587
2588 fl->fl_start = ffl->start;
2589 fl->fl_end = ffl->end;
2590
2591 /*
2592 * Convert pid into init's pid namespace. The locks API will
2593 * translate it into the caller's pid namespace.
2594 */
2595 rcu_read_lock();
2596 fl->fl_pid = pid_nr_ns(find_pid_ns(ffl->pid, fc->pid_ns), &init_pid_ns);
2597 rcu_read_unlock();
2598 break;
2599
2600 default:
2601 return -EIO;
2602 }
2603 fl->fl_type = ffl->type;
2604 return 0;
2605 }
2606
fuse_lk_fill(struct fuse_args * args,struct file * file,const struct file_lock * fl,int opcode,pid_t pid,int flock,struct fuse_lk_in * inarg)2607 static void fuse_lk_fill(struct fuse_args *args, struct file *file,
2608 const struct file_lock *fl, int opcode, pid_t pid,
2609 int flock, struct fuse_lk_in *inarg)
2610 {
2611 struct inode *inode = file_inode(file);
2612 struct fuse_conn *fc = get_fuse_conn(inode);
2613 struct fuse_file *ff = file->private_data;
2614
2615 memset(inarg, 0, sizeof(*inarg));
2616 inarg->fh = ff->fh;
2617 inarg->owner = fuse_lock_owner_id(fc, fl->fl_owner);
2618 inarg->lk.start = fl->fl_start;
2619 inarg->lk.end = fl->fl_end;
2620 inarg->lk.type = fl->fl_type;
2621 inarg->lk.pid = pid;
2622 if (flock)
2623 inarg->lk_flags |= FUSE_LK_FLOCK;
2624 args->opcode = opcode;
2625 args->nodeid = get_node_id(inode);
2626 args->in_numargs = 1;
2627 args->in_args[0].size = sizeof(*inarg);
2628 args->in_args[0].value = inarg;
2629 }
2630
fuse_getlk(struct file * file,struct file_lock * fl)2631 static int fuse_getlk(struct file *file, struct file_lock *fl)
2632 {
2633 struct inode *inode = file_inode(file);
2634 struct fuse_mount *fm = get_fuse_mount(inode);
2635 FUSE_ARGS(args);
2636 struct fuse_lk_in inarg;
2637 struct fuse_lk_out outarg;
2638 int err;
2639
2640 fuse_lk_fill(&args, file, fl, FUSE_GETLK, 0, 0, &inarg);
2641 args.out_numargs = 1;
2642 args.out_args[0].size = sizeof(outarg);
2643 args.out_args[0].value = &outarg;
2644 err = fuse_simple_request(fm, &args);
2645 if (!err)
2646 err = convert_fuse_file_lock(fm->fc, &outarg.lk, fl);
2647
2648 return err;
2649 }
2650
fuse_setlk(struct file * file,struct file_lock * fl,int flock)2651 static int fuse_setlk(struct file *file, struct file_lock *fl, int flock)
2652 {
2653 struct inode *inode = file_inode(file);
2654 struct fuse_mount *fm = get_fuse_mount(inode);
2655 FUSE_ARGS(args);
2656 struct fuse_lk_in inarg;
2657 int opcode = (fl->fl_flags & FL_SLEEP) ? FUSE_SETLKW : FUSE_SETLK;
2658 struct pid *pid = fl->fl_type != F_UNLCK ? task_tgid(current) : NULL;
2659 pid_t pid_nr = pid_nr_ns(pid, fm->fc->pid_ns);
2660 int err;
2661
2662 if (fl->fl_lmops && fl->fl_lmops->lm_grant) {
2663 /* NLM needs asynchronous locks, which we don't support yet */
2664 return -ENOLCK;
2665 }
2666
2667 /* Unlock on close is handled by the flush method */
2668 if ((fl->fl_flags & FL_CLOSE_POSIX) == FL_CLOSE_POSIX)
2669 return 0;
2670
2671 fuse_lk_fill(&args, file, fl, opcode, pid_nr, flock, &inarg);
2672 err = fuse_simple_request(fm, &args);
2673
2674 /* locking is restartable */
2675 if (err == -EINTR)
2676 err = -ERESTARTSYS;
2677
2678 return err;
2679 }
2680
fuse_file_lock(struct file * file,int cmd,struct file_lock * fl)2681 static int fuse_file_lock(struct file *file, int cmd, struct file_lock *fl)
2682 {
2683 struct inode *inode = file_inode(file);
2684 struct fuse_conn *fc = get_fuse_conn(inode);
2685 int err;
2686
2687 if (cmd == F_CANCELLK) {
2688 err = 0;
2689 } else if (cmd == F_GETLK) {
2690 if (fc->no_lock) {
2691 posix_test_lock(file, fl);
2692 err = 0;
2693 } else
2694 err = fuse_getlk(file, fl);
2695 } else {
2696 if (fc->no_lock)
2697 err = posix_lock_file(file, fl, NULL);
2698 else
2699 err = fuse_setlk(file, fl, 0);
2700 }
2701 return err;
2702 }
2703
fuse_file_flock(struct file * file,int cmd,struct file_lock * fl)2704 static int fuse_file_flock(struct file *file, int cmd, struct file_lock *fl)
2705 {
2706 struct inode *inode = file_inode(file);
2707 struct fuse_conn *fc = get_fuse_conn(inode);
2708 struct fuse_file *ff = file->private_data;
2709 int err;
2710
2711 #ifdef CONFIG_FUSE_BPF
2712 /* TODO - this is simply passthrough, not a proper BPF filter */
2713 if (ff->backing_file)
2714 return fuse_file_flock_backing(file, cmd, fl);
2715 #endif
2716
2717 if (fc->no_flock) {
2718 err = locks_lock_file_wait(file, fl);
2719 } else {
2720
2721 /* emulate flock with POSIX locks */
2722 ff->flock = true;
2723 err = fuse_setlk(file, fl, 1);
2724 }
2725
2726 return err;
2727 }
2728
fuse_bmap(struct address_space * mapping,sector_t block)2729 static sector_t fuse_bmap(struct address_space *mapping, sector_t block)
2730 {
2731 struct inode *inode = mapping->host;
2732 struct fuse_mount *fm = get_fuse_mount(inode);
2733 FUSE_ARGS(args);
2734 struct fuse_bmap_in inarg;
2735 struct fuse_bmap_out outarg;
2736 int err;
2737
2738 if (!inode->i_sb->s_bdev || fm->fc->no_bmap)
2739 return 0;
2740
2741 memset(&inarg, 0, sizeof(inarg));
2742 inarg.block = block;
2743 inarg.blocksize = inode->i_sb->s_blocksize;
2744 args.opcode = FUSE_BMAP;
2745 args.nodeid = get_node_id(inode);
2746 args.in_numargs = 1;
2747 args.in_args[0].size = sizeof(inarg);
2748 args.in_args[0].value = &inarg;
2749 args.out_numargs = 1;
2750 args.out_args[0].size = sizeof(outarg);
2751 args.out_args[0].value = &outarg;
2752 err = fuse_simple_request(fm, &args);
2753 if (err == -ENOSYS)
2754 fm->fc->no_bmap = 1;
2755
2756 return err ? 0 : outarg.block;
2757 }
2758
fuse_lseek(struct file * file,loff_t offset,int whence)2759 static loff_t fuse_lseek(struct file *file, loff_t offset, int whence)
2760 {
2761 struct inode *inode = file->f_mapping->host;
2762 struct fuse_mount *fm = get_fuse_mount(inode);
2763 struct fuse_file *ff = file->private_data;
2764 FUSE_ARGS(args);
2765 struct fuse_lseek_in inarg = {
2766 .fh = ff->fh,
2767 .offset = offset,
2768 .whence = whence
2769 };
2770 struct fuse_lseek_out outarg;
2771 int err;
2772
2773 if (fm->fc->no_lseek)
2774 goto fallback;
2775
2776 args.opcode = FUSE_LSEEK;
2777 args.nodeid = ff->nodeid;
2778 args.in_numargs = 1;
2779 args.in_args[0].size = sizeof(inarg);
2780 args.in_args[0].value = &inarg;
2781 args.out_numargs = 1;
2782 args.out_args[0].size = sizeof(outarg);
2783 args.out_args[0].value = &outarg;
2784 err = fuse_simple_request(fm, &args);
2785 if (err) {
2786 if (err == -ENOSYS) {
2787 fm->fc->no_lseek = 1;
2788 goto fallback;
2789 }
2790 return err;
2791 }
2792
2793 return vfs_setpos(file, outarg.offset, inode->i_sb->s_maxbytes);
2794
2795 fallback:
2796 err = fuse_update_attributes(inode, file, STATX_SIZE);
2797 if (!err)
2798 return generic_file_llseek(file, offset, whence);
2799 else
2800 return err;
2801 }
2802
fuse_file_llseek(struct file * file,loff_t offset,int whence)2803 static loff_t fuse_file_llseek(struct file *file, loff_t offset, int whence)
2804 {
2805 loff_t retval;
2806 struct inode *inode = file_inode(file);
2807 #ifdef CONFIG_FUSE_BPF
2808 struct fuse_err_ret fer;
2809
2810 fer = fuse_bpf_backing(inode, struct fuse_lseek_io,
2811 fuse_lseek_initialize,
2812 fuse_lseek_backing,
2813 fuse_lseek_finalize,
2814 file, offset, whence);
2815 if (fer.ret)
2816 return PTR_ERR(fer.result);
2817 #endif
2818
2819 switch (whence) {
2820 case SEEK_SET:
2821 case SEEK_CUR:
2822 /* No i_mutex protection necessary for SEEK_CUR and SEEK_SET */
2823 retval = generic_file_llseek(file, offset, whence);
2824 break;
2825 case SEEK_END:
2826 inode_lock(inode);
2827 retval = fuse_update_attributes(inode, file, STATX_SIZE);
2828 if (!retval)
2829 retval = generic_file_llseek(file, offset, whence);
2830 inode_unlock(inode);
2831 break;
2832 case SEEK_HOLE:
2833 case SEEK_DATA:
2834 inode_lock(inode);
2835 retval = fuse_lseek(file, offset, whence);
2836 inode_unlock(inode);
2837 break;
2838 default:
2839 retval = -EINVAL;
2840 }
2841
2842 return retval;
2843 }
2844
2845 /*
2846 * All files which have been polled are linked to RB tree
2847 * fuse_conn->polled_files which is indexed by kh. Walk the tree and
2848 * find the matching one.
2849 */
fuse_find_polled_node(struct fuse_conn * fc,u64 kh,struct rb_node ** parent_out)2850 static struct rb_node **fuse_find_polled_node(struct fuse_conn *fc, u64 kh,
2851 struct rb_node **parent_out)
2852 {
2853 struct rb_node **link = &fc->polled_files.rb_node;
2854 struct rb_node *last = NULL;
2855
2856 while (*link) {
2857 struct fuse_file *ff;
2858
2859 last = *link;
2860 ff = rb_entry(last, struct fuse_file, polled_node);
2861
2862 if (kh < ff->kh)
2863 link = &last->rb_left;
2864 else if (kh > ff->kh)
2865 link = &last->rb_right;
2866 else
2867 return link;
2868 }
2869
2870 if (parent_out)
2871 *parent_out = last;
2872 return link;
2873 }
2874
2875 /*
2876 * The file is about to be polled. Make sure it's on the polled_files
2877 * RB tree. Note that files once added to the polled_files tree are
2878 * not removed before the file is released. This is because a file
2879 * polled once is likely to be polled again.
2880 */
fuse_register_polled_file(struct fuse_conn * fc,struct fuse_file * ff)2881 static void fuse_register_polled_file(struct fuse_conn *fc,
2882 struct fuse_file *ff)
2883 {
2884 spin_lock(&fc->lock);
2885 if (RB_EMPTY_NODE(&ff->polled_node)) {
2886 struct rb_node **link, *parent;
2887
2888 link = fuse_find_polled_node(fc, ff->kh, &parent);
2889 BUG_ON(*link);
2890 rb_link_node(&ff->polled_node, parent, link);
2891 rb_insert_color(&ff->polled_node, &fc->polled_files);
2892 }
2893 spin_unlock(&fc->lock);
2894 }
2895
fuse_file_poll(struct file * file,poll_table * wait)2896 __poll_t fuse_file_poll(struct file *file, poll_table *wait)
2897 {
2898 struct fuse_file *ff = file->private_data;
2899 struct fuse_mount *fm = ff->fm;
2900 struct fuse_poll_in inarg = { .fh = ff->fh, .kh = ff->kh };
2901 struct fuse_poll_out outarg;
2902 FUSE_ARGS(args);
2903 int err;
2904
2905 if (fm->fc->no_poll)
2906 return DEFAULT_POLLMASK;
2907
2908 poll_wait(file, &ff->poll_wait, wait);
2909 inarg.events = mangle_poll(poll_requested_events(wait));
2910
2911 /*
2912 * Ask for notification iff there's someone waiting for it.
2913 * The client may ignore the flag and always notify.
2914 */
2915 if (waitqueue_active(&ff->poll_wait)) {
2916 inarg.flags |= FUSE_POLL_SCHEDULE_NOTIFY;
2917 fuse_register_polled_file(fm->fc, ff);
2918 }
2919
2920 args.opcode = FUSE_POLL;
2921 args.nodeid = ff->nodeid;
2922 args.in_numargs = 1;
2923 args.in_args[0].size = sizeof(inarg);
2924 args.in_args[0].value = &inarg;
2925 args.out_numargs = 1;
2926 args.out_args[0].size = sizeof(outarg);
2927 args.out_args[0].value = &outarg;
2928 err = fuse_simple_request(fm, &args);
2929
2930 if (!err)
2931 return demangle_poll(outarg.revents);
2932 if (err == -ENOSYS) {
2933 fm->fc->no_poll = 1;
2934 return DEFAULT_POLLMASK;
2935 }
2936 return EPOLLERR;
2937 }
2938 EXPORT_SYMBOL_GPL(fuse_file_poll);
2939
2940 /*
2941 * This is called from fuse_handle_notify() on FUSE_NOTIFY_POLL and
2942 * wakes up the poll waiters.
2943 */
fuse_notify_poll_wakeup(struct fuse_conn * fc,struct fuse_notify_poll_wakeup_out * outarg)2944 int fuse_notify_poll_wakeup(struct fuse_conn *fc,
2945 struct fuse_notify_poll_wakeup_out *outarg)
2946 {
2947 u64 kh = outarg->kh;
2948 struct rb_node **link;
2949
2950 spin_lock(&fc->lock);
2951
2952 link = fuse_find_polled_node(fc, kh, NULL);
2953 if (*link) {
2954 struct fuse_file *ff;
2955
2956 ff = rb_entry(*link, struct fuse_file, polled_node);
2957 wake_up_interruptible_sync(&ff->poll_wait);
2958 }
2959
2960 spin_unlock(&fc->lock);
2961 return 0;
2962 }
2963
fuse_do_truncate(struct file * file)2964 static void fuse_do_truncate(struct file *file)
2965 {
2966 struct inode *inode = file->f_mapping->host;
2967 struct iattr attr;
2968
2969 attr.ia_valid = ATTR_SIZE;
2970 attr.ia_size = i_size_read(inode);
2971
2972 attr.ia_file = file;
2973 attr.ia_valid |= ATTR_FILE;
2974
2975 fuse_do_setattr(file_dentry(file), &attr, file);
2976 }
2977
fuse_round_up(struct fuse_conn * fc,loff_t off)2978 static inline loff_t fuse_round_up(struct fuse_conn *fc, loff_t off)
2979 {
2980 return round_up(off, fc->max_pages << PAGE_SHIFT);
2981 }
2982
2983 static ssize_t
fuse_direct_IO(struct kiocb * iocb,struct iov_iter * iter)2984 fuse_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
2985 {
2986 DECLARE_COMPLETION_ONSTACK(wait);
2987 ssize_t ret = 0;
2988 struct file *file = iocb->ki_filp;
2989 struct fuse_file *ff = file->private_data;
2990 loff_t pos = 0;
2991 struct inode *inode;
2992 loff_t i_size;
2993 size_t count = iov_iter_count(iter), shortened = 0;
2994 loff_t offset = iocb->ki_pos;
2995 struct fuse_io_priv *io;
2996
2997 pos = offset;
2998 inode = file->f_mapping->host;
2999 i_size = i_size_read(inode);
3000
3001 if ((iov_iter_rw(iter) == READ) && (offset >= i_size))
3002 return 0;
3003
3004 io = kmalloc(sizeof(struct fuse_io_priv), GFP_KERNEL);
3005 if (!io)
3006 return -ENOMEM;
3007 spin_lock_init(&io->lock);
3008 kref_init(&io->refcnt);
3009 io->reqs = 1;
3010 io->bytes = -1;
3011 io->size = 0;
3012 io->offset = offset;
3013 io->write = (iov_iter_rw(iter) == WRITE);
3014 io->err = 0;
3015 /*
3016 * By default, we want to optimize all I/Os with async request
3017 * submission to the client filesystem if supported.
3018 */
3019 io->async = ff->fm->fc->async_dio;
3020 io->iocb = iocb;
3021 io->blocking = is_sync_kiocb(iocb);
3022
3023 /* optimization for short read */
3024 if (io->async && !io->write && offset + count > i_size) {
3025 iov_iter_truncate(iter, fuse_round_up(ff->fm->fc, i_size - offset));
3026 shortened = count - iov_iter_count(iter);
3027 count -= shortened;
3028 }
3029
3030 /*
3031 * We cannot asynchronously extend the size of a file.
3032 * In such case the aio will behave exactly like sync io.
3033 */
3034 if ((offset + count > i_size) && io->write)
3035 io->blocking = true;
3036
3037 if (io->async && io->blocking) {
3038 /*
3039 * Additional reference to keep io around after
3040 * calling fuse_aio_complete()
3041 */
3042 kref_get(&io->refcnt);
3043 io->done = &wait;
3044 }
3045
3046 if (iov_iter_rw(iter) == WRITE) {
3047 ret = fuse_direct_io(io, iter, &pos, FUSE_DIO_WRITE);
3048 fuse_invalidate_attr_mask(inode, FUSE_STATX_MODSIZE);
3049 } else {
3050 ret = __fuse_direct_read(io, iter, &pos);
3051 }
3052 iov_iter_reexpand(iter, iov_iter_count(iter) + shortened);
3053
3054 if (io->async) {
3055 bool blocking = io->blocking;
3056
3057 fuse_aio_complete(io, ret < 0 ? ret : 0, -1);
3058
3059 /* we have a non-extending, async request, so return */
3060 if (!blocking)
3061 return -EIOCBQUEUED;
3062
3063 wait_for_completion(&wait);
3064 ret = fuse_get_res_by_io(io);
3065 }
3066
3067 kref_put(&io->refcnt, fuse_io_release);
3068
3069 if (iov_iter_rw(iter) == WRITE) {
3070 fuse_write_update_attr(inode, pos, ret);
3071 if (ret < 0 && offset + count > i_size)
3072 fuse_do_truncate(file);
3073 }
3074
3075 return ret;
3076 }
3077
fuse_writeback_range(struct inode * inode,loff_t start,loff_t end)3078 static int fuse_writeback_range(struct inode *inode, loff_t start, loff_t end)
3079 {
3080 int err = filemap_write_and_wait_range(inode->i_mapping, start, LLONG_MAX);
3081
3082 if (!err)
3083 fuse_sync_writes(inode);
3084
3085 return err;
3086 }
3087
fuse_file_fallocate(struct file * file,int mode,loff_t offset,loff_t length)3088 static long fuse_file_fallocate(struct file *file, int mode, loff_t offset,
3089 loff_t length)
3090 {
3091 struct fuse_file *ff = file->private_data;
3092 struct inode *inode = file_inode(file);
3093 struct fuse_inode *fi = get_fuse_inode(inode);
3094 struct fuse_mount *fm = ff->fm;
3095 FUSE_ARGS(args);
3096 struct fuse_fallocate_in inarg = {
3097 .fh = ff->fh,
3098 .offset = offset,
3099 .length = length,
3100 .mode = mode
3101 };
3102 int err;
3103 bool block_faults = FUSE_IS_DAX(inode) &&
3104 (!(mode & FALLOC_FL_KEEP_SIZE) ||
3105 (mode & (FALLOC_FL_PUNCH_HOLE | FALLOC_FL_ZERO_RANGE)));
3106
3107 #ifdef CONFIG_FUSE_BPF
3108 struct fuse_err_ret fer;
3109
3110 fer = fuse_bpf_backing(inode, struct fuse_fallocate_in,
3111 fuse_file_fallocate_initialize,
3112 fuse_file_fallocate_backing,
3113 fuse_file_fallocate_finalize,
3114 file, mode, offset, length);
3115 if (fer.ret)
3116 return PTR_ERR(fer.result);
3117 #endif
3118
3119 if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE |
3120 FALLOC_FL_ZERO_RANGE))
3121 return -EOPNOTSUPP;
3122
3123 if (fm->fc->no_fallocate)
3124 return -EOPNOTSUPP;
3125
3126 inode_lock(inode);
3127 if (block_faults) {
3128 filemap_invalidate_lock(inode->i_mapping);
3129 err = fuse_dax_break_layouts(inode, 0, 0);
3130 if (err)
3131 goto out;
3132 }
3133
3134 if (mode & (FALLOC_FL_PUNCH_HOLE | FALLOC_FL_ZERO_RANGE)) {
3135 loff_t endbyte = offset + length - 1;
3136
3137 err = fuse_writeback_range(inode, offset, endbyte);
3138 if (err)
3139 goto out;
3140 }
3141
3142 if (!(mode & FALLOC_FL_KEEP_SIZE) &&
3143 offset + length > i_size_read(inode)) {
3144 err = inode_newsize_ok(inode, offset + length);
3145 if (err)
3146 goto out;
3147 }
3148
3149 err = file_modified(file);
3150 if (err)
3151 goto out;
3152
3153 if (!(mode & FALLOC_FL_KEEP_SIZE))
3154 set_bit(FUSE_I_SIZE_UNSTABLE, &fi->state);
3155
3156 args.opcode = FUSE_FALLOCATE;
3157 args.nodeid = ff->nodeid;
3158 args.in_numargs = 1;
3159 args.in_args[0].size = sizeof(inarg);
3160 args.in_args[0].value = &inarg;
3161 err = fuse_simple_request(fm, &args);
3162 if (err == -ENOSYS) {
3163 fm->fc->no_fallocate = 1;
3164 err = -EOPNOTSUPP;
3165 }
3166 if (err)
3167 goto out;
3168
3169 /* we could have extended the file */
3170 if (!(mode & FALLOC_FL_KEEP_SIZE)) {
3171 if (fuse_write_update_attr(inode, offset + length, length))
3172 file_update_time(file);
3173 }
3174
3175 if (mode & (FALLOC_FL_PUNCH_HOLE | FALLOC_FL_ZERO_RANGE))
3176 truncate_pagecache_range(inode, offset, offset + length - 1);
3177
3178 fuse_invalidate_attr_mask(inode, FUSE_STATX_MODSIZE);
3179
3180 out:
3181 if (!(mode & FALLOC_FL_KEEP_SIZE))
3182 clear_bit(FUSE_I_SIZE_UNSTABLE, &fi->state);
3183
3184 if (block_faults)
3185 filemap_invalidate_unlock(inode->i_mapping);
3186
3187 inode_unlock(inode);
3188
3189 fuse_flush_time_update(inode);
3190
3191 return err;
3192 }
3193
__fuse_copy_file_range(struct file * file_in,loff_t pos_in,struct file * file_out,loff_t pos_out,size_t len,unsigned int flags)3194 static ssize_t __fuse_copy_file_range(struct file *file_in, loff_t pos_in,
3195 struct file *file_out, loff_t pos_out,
3196 size_t len, unsigned int flags)
3197 {
3198 struct fuse_file *ff_in = file_in->private_data;
3199 struct fuse_file *ff_out = file_out->private_data;
3200 struct inode *inode_in = file_inode(file_in);
3201 struct inode *inode_out = file_inode(file_out);
3202 struct fuse_inode *fi_out = get_fuse_inode(inode_out);
3203 struct fuse_mount *fm = ff_in->fm;
3204 struct fuse_conn *fc = fm->fc;
3205 FUSE_ARGS(args);
3206 struct fuse_copy_file_range_in inarg = {
3207 .fh_in = ff_in->fh,
3208 .off_in = pos_in,
3209 .nodeid_out = ff_out->nodeid,
3210 .fh_out = ff_out->fh,
3211 .off_out = pos_out,
3212 .len = len,
3213 .flags = flags
3214 };
3215 struct fuse_write_out outarg;
3216 ssize_t err;
3217 /* mark unstable when write-back is not used, and file_out gets
3218 * extended */
3219 bool is_unstable = (!fc->writeback_cache) &&
3220 ((pos_out + len) > inode_out->i_size);
3221
3222 #ifdef CONFIG_FUSE_BPF
3223 struct fuse_err_ret fer;
3224
3225 fer = fuse_bpf_backing(file_in->f_inode, struct fuse_copy_file_range_io,
3226 fuse_copy_file_range_initialize,
3227 fuse_copy_file_range_backing,
3228 fuse_copy_file_range_finalize,
3229 file_in, pos_in, file_out, pos_out, len, flags);
3230 if (fer.ret)
3231 return PTR_ERR(fer.result);
3232 #endif
3233
3234 if (fc->no_copy_file_range)
3235 return -EOPNOTSUPP;
3236
3237 if (file_inode(file_in)->i_sb != file_inode(file_out)->i_sb)
3238 return -EXDEV;
3239
3240 inode_lock(inode_in);
3241 err = fuse_writeback_range(inode_in, pos_in, pos_in + len - 1);
3242 inode_unlock(inode_in);
3243 if (err)
3244 return err;
3245
3246 inode_lock(inode_out);
3247
3248 err = file_modified(file_out);
3249 if (err)
3250 goto out;
3251
3252 /*
3253 * Write out dirty pages in the destination file before sending the COPY
3254 * request to userspace. After the request is completed, truncate off
3255 * pages (including partial ones) from the cache that have been copied,
3256 * since these contain stale data at that point.
3257 *
3258 * This should be mostly correct, but if the COPY writes to partial
3259 * pages (at the start or end) and the parts not covered by the COPY are
3260 * written through a memory map after calling fuse_writeback_range(),
3261 * then these partial page modifications will be lost on truncation.
3262 *
3263 * It is unlikely that someone would rely on such mixed style
3264 * modifications. Yet this does give less guarantees than if the
3265 * copying was performed with write(2).
3266 *
3267 * To fix this a mapping->invalidate_lock could be used to prevent new
3268 * faults while the copy is ongoing.
3269 */
3270 err = fuse_writeback_range(inode_out, pos_out, pos_out + len - 1);
3271 if (err)
3272 goto out;
3273
3274 if (is_unstable)
3275 set_bit(FUSE_I_SIZE_UNSTABLE, &fi_out->state);
3276
3277 args.opcode = FUSE_COPY_FILE_RANGE;
3278 args.nodeid = ff_in->nodeid;
3279 args.in_numargs = 1;
3280 args.in_args[0].size = sizeof(inarg);
3281 args.in_args[0].value = &inarg;
3282 args.out_numargs = 1;
3283 args.out_args[0].size = sizeof(outarg);
3284 args.out_args[0].value = &outarg;
3285 err = fuse_simple_request(fm, &args);
3286 if (err == -ENOSYS) {
3287 fc->no_copy_file_range = 1;
3288 err = -EOPNOTSUPP;
3289 }
3290 if (err)
3291 goto out;
3292
3293 truncate_inode_pages_range(inode_out->i_mapping,
3294 ALIGN_DOWN(pos_out, PAGE_SIZE),
3295 ALIGN(pos_out + outarg.size, PAGE_SIZE) - 1);
3296
3297 file_update_time(file_out);
3298 fuse_write_update_attr(inode_out, pos_out + outarg.size, outarg.size);
3299
3300 err = outarg.size;
3301 out:
3302 if (is_unstable)
3303 clear_bit(FUSE_I_SIZE_UNSTABLE, &fi_out->state);
3304
3305 inode_unlock(inode_out);
3306 file_accessed(file_in);
3307
3308 fuse_flush_time_update(inode_out);
3309
3310 return err;
3311 }
3312
fuse_copy_file_range(struct file * src_file,loff_t src_off,struct file * dst_file,loff_t dst_off,size_t len,unsigned int flags)3313 static ssize_t fuse_copy_file_range(struct file *src_file, loff_t src_off,
3314 struct file *dst_file, loff_t dst_off,
3315 size_t len, unsigned int flags)
3316 {
3317 ssize_t ret;
3318
3319 ret = __fuse_copy_file_range(src_file, src_off, dst_file, dst_off,
3320 len, flags);
3321
3322 if (ret == -EOPNOTSUPP || ret == -EXDEV)
3323 ret = generic_copy_file_range(src_file, src_off, dst_file,
3324 dst_off, len, flags);
3325 return ret;
3326 }
3327
3328 static const struct file_operations fuse_file_operations = {
3329 .llseek = fuse_file_llseek,
3330 .read_iter = fuse_file_read_iter,
3331 .write_iter = fuse_file_write_iter,
3332 .mmap = fuse_file_mmap,
3333 .open = fuse_open,
3334 .flush = fuse_flush,
3335 .release = fuse_release,
3336 .fsync = fuse_fsync,
3337 .lock = fuse_file_lock,
3338 .get_unmapped_area = thp_get_unmapped_area,
3339 .flock = fuse_file_flock,
3340 .splice_read = generic_file_splice_read,
3341 .splice_write = iter_file_splice_write,
3342 .unlocked_ioctl = fuse_file_ioctl,
3343 .compat_ioctl = fuse_file_compat_ioctl,
3344 .poll = fuse_file_poll,
3345 .fallocate = fuse_file_fallocate,
3346 .copy_file_range = fuse_copy_file_range,
3347 };
3348
3349 static const struct address_space_operations fuse_file_aops = {
3350 .read_folio = fuse_read_folio,
3351 .readahead = fuse_readahead,
3352 .writepage = fuse_writepage,
3353 .writepages = fuse_writepages,
3354 .launder_folio = fuse_launder_folio,
3355 .dirty_folio = filemap_dirty_folio,
3356 .bmap = fuse_bmap,
3357 .direct_IO = fuse_direct_IO,
3358 .write_begin = fuse_write_begin,
3359 .write_end = fuse_write_end,
3360 };
3361
fuse_init_file_inode(struct inode * inode,unsigned int flags)3362 void fuse_init_file_inode(struct inode *inode, unsigned int flags)
3363 {
3364 struct fuse_inode *fi = get_fuse_inode(inode);
3365
3366 inode->i_fop = &fuse_file_operations;
3367 inode->i_data.a_ops = &fuse_file_aops;
3368
3369 INIT_LIST_HEAD(&fi->write_files);
3370 INIT_LIST_HEAD(&fi->queued_writes);
3371 fi->writectr = 0;
3372 init_waitqueue_head(&fi->page_waitq);
3373 fi->writepages = RB_ROOT;
3374
3375 if (IS_ENABLED(CONFIG_FUSE_DAX))
3376 fuse_dax_inode_init(inode, flags);
3377 }
3378