1 /*
2 FUSE: Filesystem in Userspace
3 Copyright (C) 2001-2008 Miklos Szeredi <miklos@szeredi.hu>
4
5 This program can be distributed under the terms of the GNU GPL.
6 See the file COPYING.
7 */
8
9 #include "fuse_i.h"
10
11 #include <linux/pagemap.h>
12 #include <linux/slab.h>
13 #include <linux/kernel.h>
14 #include <linux/sched.h>
15 #include <linux/sched/signal.h>
16 #include <linux/module.h>
17 #include <linux/swap.h>
18 #include <linux/falloc.h>
19 #include <linux/uio.h>
20 #include <linux/fs.h>
21 #include <linux/filelock.h>
22 #include <linux/splice.h>
23
fuse_send_open(struct fuse_mount * fm,u64 nodeid,unsigned int open_flags,int opcode,struct fuse_open_out * outargp)24 static int fuse_send_open(struct fuse_mount *fm, u64 nodeid,
25 unsigned int open_flags, int opcode,
26 struct fuse_open_out *outargp)
27 {
28 struct fuse_open_in inarg;
29 FUSE_ARGS(args);
30
31 memset(&inarg, 0, sizeof(inarg));
32 inarg.flags = open_flags & ~(O_CREAT | O_EXCL | O_NOCTTY);
33 if (!fm->fc->atomic_o_trunc)
34 inarg.flags &= ~O_TRUNC;
35
36 if (fm->fc->handle_killpriv_v2 &&
37 (inarg.flags & O_TRUNC) && !capable(CAP_FSETID)) {
38 inarg.open_flags |= FUSE_OPEN_KILL_SUIDGID;
39 }
40
41 args.opcode = opcode;
42 args.nodeid = nodeid;
43 args.in_numargs = 1;
44 args.in_args[0].size = sizeof(inarg);
45 args.in_args[0].value = &inarg;
46 args.out_numargs = 1;
47 args.out_args[0].size = sizeof(*outargp);
48 args.out_args[0].value = outargp;
49
50 return fuse_simple_request(fm, &args);
51 }
52
53 struct fuse_release_args {
54 struct fuse_args args;
55 struct fuse_release_in inarg;
56 struct inode *inode;
57 };
58
fuse_file_alloc(struct fuse_mount * fm)59 struct fuse_file *fuse_file_alloc(struct fuse_mount *fm)
60 {
61 struct fuse_file *ff;
62
63 ff = kzalloc(sizeof(struct fuse_file), GFP_KERNEL_ACCOUNT);
64 if (unlikely(!ff))
65 return NULL;
66
67 ff->fm = fm;
68 ff->release_args = kzalloc(sizeof(*ff->release_args),
69 GFP_KERNEL_ACCOUNT);
70 if (!ff->release_args) {
71 kfree(ff);
72 return NULL;
73 }
74
75 INIT_LIST_HEAD(&ff->write_entry);
76 mutex_init(&ff->readdir.lock);
77 refcount_set(&ff->count, 1);
78 RB_CLEAR_NODE(&ff->polled_node);
79 init_waitqueue_head(&ff->poll_wait);
80
81 ff->kh = atomic64_inc_return(&fm->fc->khctr);
82
83 return ff;
84 }
85
fuse_file_free(struct fuse_file * ff)86 void fuse_file_free(struct fuse_file *ff)
87 {
88 kfree(ff->release_args);
89 mutex_destroy(&ff->readdir.lock);
90 kfree(ff);
91 }
92
fuse_file_get(struct fuse_file * ff)93 static struct fuse_file *fuse_file_get(struct fuse_file *ff)
94 {
95 refcount_inc(&ff->count);
96 return ff;
97 }
98
fuse_release_end(struct fuse_mount * fm,struct fuse_args * args,int error)99 static void fuse_release_end(struct fuse_mount *fm, struct fuse_args *args,
100 int error)
101 {
102 struct fuse_release_args *ra = container_of(args, typeof(*ra), args);
103
104 iput(ra->inode);
105 kfree(ra);
106 }
107
fuse_file_put(struct fuse_file * ff,bool sync,bool isdir)108 static void fuse_file_put(struct fuse_file *ff, bool sync, bool isdir)
109 {
110 if (refcount_dec_and_test(&ff->count)) {
111 struct fuse_args *args = &ff->release_args->args;
112
113 if (isdir ? ff->fm->fc->no_opendir : ff->fm->fc->no_open) {
114 /* Do nothing when client does not implement 'open' */
115 fuse_release_end(ff->fm, args, 0);
116 } else if (sync) {
117 fuse_simple_request(ff->fm, args);
118 fuse_release_end(ff->fm, args, 0);
119 } else {
120 args->end = fuse_release_end;
121 if (fuse_simple_background(ff->fm, args,
122 GFP_KERNEL | __GFP_NOFAIL))
123 fuse_release_end(ff->fm, args, -ENOTCONN);
124 }
125 kfree(ff);
126 }
127 }
128
fuse_file_open(struct fuse_mount * fm,u64 nodeid,unsigned int open_flags,bool isdir)129 struct fuse_file *fuse_file_open(struct fuse_mount *fm, u64 nodeid,
130 unsigned int open_flags, bool isdir)
131 {
132 struct fuse_conn *fc = fm->fc;
133 struct fuse_file *ff;
134 int opcode = isdir ? FUSE_OPENDIR : FUSE_OPEN;
135
136 ff = fuse_file_alloc(fm);
137 if (!ff)
138 return ERR_PTR(-ENOMEM);
139
140 ff->fh = 0;
141 /* Default for no-open */
142 ff->open_flags = FOPEN_KEEP_CACHE | (isdir ? FOPEN_CACHE_DIR : 0);
143 if (isdir ? !fc->no_opendir : !fc->no_open) {
144 struct fuse_open_out outarg;
145 int err;
146
147 err = fuse_send_open(fm, nodeid, open_flags, opcode, &outarg);
148 if (!err) {
149 ff->fh = outarg.fh;
150 ff->open_flags = outarg.open_flags;
151
152 } else if (err != -ENOSYS) {
153 fuse_file_free(ff);
154 return ERR_PTR(err);
155 } else {
156 if (isdir)
157 fc->no_opendir = 1;
158 else
159 fc->no_open = 1;
160 }
161 }
162
163 if (isdir)
164 ff->open_flags &= ~FOPEN_DIRECT_IO;
165
166 ff->nodeid = nodeid;
167
168 return ff;
169 }
170
fuse_do_open(struct fuse_mount * fm,u64 nodeid,struct file * file,bool isdir)171 int fuse_do_open(struct fuse_mount *fm, u64 nodeid, struct file *file,
172 bool isdir)
173 {
174 struct fuse_file *ff = fuse_file_open(fm, nodeid, file->f_flags, isdir);
175
176 if (!IS_ERR(ff))
177 file->private_data = ff;
178
179 return PTR_ERR_OR_ZERO(ff);
180 }
181 EXPORT_SYMBOL_GPL(fuse_do_open);
182
fuse_link_write_file(struct file * file)183 static void fuse_link_write_file(struct file *file)
184 {
185 struct inode *inode = file_inode(file);
186 struct fuse_inode *fi = get_fuse_inode(inode);
187 struct fuse_file *ff = file->private_data;
188 /*
189 * file may be written through mmap, so chain it onto the
190 * inodes's write_file list
191 */
192 spin_lock(&fi->lock);
193 if (list_empty(&ff->write_entry))
194 list_add(&ff->write_entry, &fi->write_files);
195 spin_unlock(&fi->lock);
196 }
197
fuse_finish_open(struct inode * inode,struct file * file)198 void fuse_finish_open(struct inode *inode, struct file *file)
199 {
200 struct fuse_file *ff = file->private_data;
201 struct fuse_conn *fc = get_fuse_conn(inode);
202
203 if (ff->open_flags & FOPEN_STREAM)
204 stream_open(inode, file);
205 else if (ff->open_flags & FOPEN_NONSEEKABLE)
206 nonseekable_open(inode, file);
207
208 if (fc->atomic_o_trunc && (file->f_flags & O_TRUNC)) {
209 struct fuse_inode *fi = get_fuse_inode(inode);
210
211 spin_lock(&fi->lock);
212 fi->attr_version = atomic64_inc_return(&fc->attr_version);
213 i_size_write(inode, 0);
214 spin_unlock(&fi->lock);
215 file_update_time(file);
216 fuse_invalidate_attr_mask(inode, FUSE_STATX_MODSIZE);
217 }
218 if ((file->f_mode & FMODE_WRITE) && fc->writeback_cache)
219 fuse_link_write_file(file);
220 }
221
fuse_open_common(struct inode * inode,struct file * file,bool isdir)222 int fuse_open_common(struct inode *inode, struct file *file, bool isdir)
223 {
224 struct fuse_mount *fm = get_fuse_mount(inode);
225 struct fuse_conn *fc = fm->fc;
226 int err;
227 bool is_wb_truncate = (file->f_flags & O_TRUNC) &&
228 fc->atomic_o_trunc &&
229 fc->writeback_cache;
230 bool dax_truncate = (file->f_flags & O_TRUNC) &&
231 fc->atomic_o_trunc && FUSE_IS_DAX(inode);
232
233 if (fuse_is_bad(inode))
234 return -EIO;
235
236 err = generic_file_open(inode, file);
237 if (err)
238 return err;
239
240 if (is_wb_truncate || dax_truncate)
241 inode_lock(inode);
242
243 if (dax_truncate) {
244 filemap_invalidate_lock(inode->i_mapping);
245 err = fuse_dax_break_layouts(inode, 0, 0);
246 if (err)
247 goto out_inode_unlock;
248 }
249
250 if (is_wb_truncate || dax_truncate)
251 fuse_set_nowrite(inode);
252
253 err = fuse_do_open(fm, get_node_id(inode), file, isdir);
254 if (!err)
255 fuse_finish_open(inode, file);
256
257 if (is_wb_truncate || dax_truncate)
258 fuse_release_nowrite(inode);
259 if (!err) {
260 struct fuse_file *ff = file->private_data;
261
262 if (fc->atomic_o_trunc && (file->f_flags & O_TRUNC))
263 truncate_pagecache(inode, 0);
264 else if (!(ff->open_flags & FOPEN_KEEP_CACHE))
265 invalidate_inode_pages2(inode->i_mapping);
266 }
267 if (dax_truncate)
268 filemap_invalidate_unlock(inode->i_mapping);
269 out_inode_unlock:
270 if (is_wb_truncate || dax_truncate)
271 inode_unlock(inode);
272
273 return err;
274 }
275
fuse_prepare_release(struct fuse_inode * fi,struct fuse_file * ff,unsigned int flags,int opcode)276 static void fuse_prepare_release(struct fuse_inode *fi, struct fuse_file *ff,
277 unsigned int flags, int opcode)
278 {
279 struct fuse_conn *fc = ff->fm->fc;
280 struct fuse_release_args *ra = ff->release_args;
281
282 /* Inode is NULL on error path of fuse_create_open() */
283 if (likely(fi)) {
284 spin_lock(&fi->lock);
285 list_del(&ff->write_entry);
286 spin_unlock(&fi->lock);
287 }
288 spin_lock(&fc->lock);
289 if (!RB_EMPTY_NODE(&ff->polled_node))
290 rb_erase(&ff->polled_node, &fc->polled_files);
291 spin_unlock(&fc->lock);
292
293 wake_up_interruptible_all(&ff->poll_wait);
294
295 ra->inarg.fh = ff->fh;
296 ra->inarg.flags = flags;
297 ra->args.in_numargs = 1;
298 ra->args.in_args[0].size = sizeof(struct fuse_release_in);
299 ra->args.in_args[0].value = &ra->inarg;
300 ra->args.opcode = opcode;
301 ra->args.nodeid = ff->nodeid;
302 ra->args.force = true;
303 ra->args.nocreds = true;
304 }
305
fuse_file_release(struct inode * inode,struct fuse_file * ff,unsigned int open_flags,fl_owner_t id,bool isdir)306 void fuse_file_release(struct inode *inode, struct fuse_file *ff,
307 unsigned int open_flags, fl_owner_t id, bool isdir)
308 {
309 struct fuse_inode *fi = get_fuse_inode(inode);
310 struct fuse_release_args *ra = ff->release_args;
311 int opcode = isdir ? FUSE_RELEASEDIR : FUSE_RELEASE;
312
313 fuse_prepare_release(fi, ff, open_flags, opcode);
314
315 if (ff->flock) {
316 ra->inarg.release_flags |= FUSE_RELEASE_FLOCK_UNLOCK;
317 ra->inarg.lock_owner = fuse_lock_owner_id(ff->fm->fc, id);
318 }
319 /* Hold inode until release is finished */
320 ra->inode = igrab(inode);
321
322 /*
323 * Normally this will send the RELEASE request, however if
324 * some asynchronous READ or WRITE requests are outstanding,
325 * the sending will be delayed.
326 *
327 * Make the release synchronous if this is a fuseblk mount,
328 * synchronous RELEASE is allowed (and desirable) in this case
329 * because the server can be trusted not to screw up.
330 */
331 fuse_file_put(ff, ff->fm->fc->destroy, isdir);
332 }
333
fuse_release_common(struct file * file,bool isdir)334 void fuse_release_common(struct file *file, bool isdir)
335 {
336 fuse_file_release(file_inode(file), file->private_data, file->f_flags,
337 (fl_owner_t) file, isdir);
338 }
339
fuse_open(struct inode * inode,struct file * file)340 static int fuse_open(struct inode *inode, struct file *file)
341 {
342 return fuse_open_common(inode, file, false);
343 }
344
fuse_release(struct inode * inode,struct file * file)345 static int fuse_release(struct inode *inode, struct file *file)
346 {
347 struct fuse_conn *fc = get_fuse_conn(inode);
348
349 /*
350 * Dirty pages might remain despite write_inode_now() call from
351 * fuse_flush() due to writes racing with the close.
352 */
353 if (fc->writeback_cache)
354 write_inode_now(inode, 1);
355
356 fuse_release_common(file, false);
357
358 /* return value is ignored by VFS */
359 return 0;
360 }
361
fuse_sync_release(struct fuse_inode * fi,struct fuse_file * ff,unsigned int flags)362 void fuse_sync_release(struct fuse_inode *fi, struct fuse_file *ff,
363 unsigned int flags)
364 {
365 WARN_ON(refcount_read(&ff->count) > 1);
366 fuse_prepare_release(fi, ff, flags, FUSE_RELEASE);
367 /*
368 * iput(NULL) is a no-op and since the refcount is 1 and everything's
369 * synchronous, we are fine with not doing igrab() here"
370 */
371 fuse_file_put(ff, true, false);
372 }
373 EXPORT_SYMBOL_GPL(fuse_sync_release);
374
375 /*
376 * Scramble the ID space with XTEA, so that the value of the files_struct
377 * pointer is not exposed to userspace.
378 */
fuse_lock_owner_id(struct fuse_conn * fc,fl_owner_t id)379 u64 fuse_lock_owner_id(struct fuse_conn *fc, fl_owner_t id)
380 {
381 u32 *k = fc->scramble_key;
382 u64 v = (unsigned long) id;
383 u32 v0 = v;
384 u32 v1 = v >> 32;
385 u32 sum = 0;
386 int i;
387
388 for (i = 0; i < 32; i++) {
389 v0 += ((v1 << 4 ^ v1 >> 5) + v1) ^ (sum + k[sum & 3]);
390 sum += 0x9E3779B9;
391 v1 += ((v0 << 4 ^ v0 >> 5) + v0) ^ (sum + k[sum>>11 & 3]);
392 }
393
394 return (u64) v0 + ((u64) v1 << 32);
395 }
396
397 struct fuse_writepage_args {
398 struct fuse_io_args ia;
399 struct rb_node writepages_entry;
400 struct list_head queue_entry;
401 struct fuse_writepage_args *next;
402 struct inode *inode;
403 struct fuse_sync_bucket *bucket;
404 };
405
fuse_find_writeback(struct fuse_inode * fi,pgoff_t idx_from,pgoff_t idx_to)406 static struct fuse_writepage_args *fuse_find_writeback(struct fuse_inode *fi,
407 pgoff_t idx_from, pgoff_t idx_to)
408 {
409 struct rb_node *n;
410
411 n = fi->writepages.rb_node;
412
413 while (n) {
414 struct fuse_writepage_args *wpa;
415 pgoff_t curr_index;
416
417 wpa = rb_entry(n, struct fuse_writepage_args, writepages_entry);
418 WARN_ON(get_fuse_inode(wpa->inode) != fi);
419 curr_index = wpa->ia.write.in.offset >> PAGE_SHIFT;
420 if (idx_from >= curr_index + wpa->ia.ap.num_pages)
421 n = n->rb_right;
422 else if (idx_to < curr_index)
423 n = n->rb_left;
424 else
425 return wpa;
426 }
427 return NULL;
428 }
429
430 /*
431 * Check if any page in a range is under writeback
432 *
433 * This is currently done by walking the list of writepage requests
434 * for the inode, which can be pretty inefficient.
435 */
fuse_range_is_writeback(struct inode * inode,pgoff_t idx_from,pgoff_t idx_to)436 static bool fuse_range_is_writeback(struct inode *inode, pgoff_t idx_from,
437 pgoff_t idx_to)
438 {
439 struct fuse_inode *fi = get_fuse_inode(inode);
440 bool found;
441
442 spin_lock(&fi->lock);
443 found = fuse_find_writeback(fi, idx_from, idx_to);
444 spin_unlock(&fi->lock);
445
446 return found;
447 }
448
fuse_page_is_writeback(struct inode * inode,pgoff_t index)449 static inline bool fuse_page_is_writeback(struct inode *inode, pgoff_t index)
450 {
451 return fuse_range_is_writeback(inode, index, index);
452 }
453
454 /*
455 * Wait for page writeback to be completed.
456 *
457 * Since fuse doesn't rely on the VM writeback tracking, this has to
458 * use some other means.
459 */
fuse_wait_on_page_writeback(struct inode * inode,pgoff_t index)460 static void fuse_wait_on_page_writeback(struct inode *inode, pgoff_t index)
461 {
462 struct fuse_inode *fi = get_fuse_inode(inode);
463
464 wait_event(fi->page_waitq, !fuse_page_is_writeback(inode, index));
465 }
466
467 /*
468 * Wait for all pending writepages on the inode to finish.
469 *
470 * This is currently done by blocking further writes with FUSE_NOWRITE
471 * and waiting for all sent writes to complete.
472 *
473 * This must be called under i_mutex, otherwise the FUSE_NOWRITE usage
474 * could conflict with truncation.
475 */
fuse_sync_writes(struct inode * inode)476 static void fuse_sync_writes(struct inode *inode)
477 {
478 fuse_set_nowrite(inode);
479 fuse_release_nowrite(inode);
480 }
481
fuse_flush(struct file * file,fl_owner_t id)482 static int fuse_flush(struct file *file, fl_owner_t id)
483 {
484 struct inode *inode = file_inode(file);
485 struct fuse_mount *fm = get_fuse_mount(inode);
486 struct fuse_file *ff = file->private_data;
487 struct fuse_flush_in inarg;
488 FUSE_ARGS(args);
489 int err;
490
491 if (fuse_is_bad(inode))
492 return -EIO;
493
494 if (ff->open_flags & FOPEN_NOFLUSH && !fm->fc->writeback_cache)
495 return 0;
496
497 err = write_inode_now(inode, 1);
498 if (err)
499 return err;
500
501 inode_lock(inode);
502 fuse_sync_writes(inode);
503 inode_unlock(inode);
504
505 err = filemap_check_errors(file->f_mapping);
506 if (err)
507 return err;
508
509 err = 0;
510 if (fm->fc->no_flush)
511 goto inval_attr_out;
512
513 memset(&inarg, 0, sizeof(inarg));
514 inarg.fh = ff->fh;
515 inarg.lock_owner = fuse_lock_owner_id(fm->fc, id);
516 args.opcode = FUSE_FLUSH;
517 args.nodeid = get_node_id(inode);
518 args.in_numargs = 1;
519 args.in_args[0].size = sizeof(inarg);
520 args.in_args[0].value = &inarg;
521 args.force = true;
522
523 err = fuse_simple_request(fm, &args);
524 if (err == -ENOSYS) {
525 fm->fc->no_flush = 1;
526 err = 0;
527 }
528
529 inval_attr_out:
530 /*
531 * In memory i_blocks is not maintained by fuse, if writeback cache is
532 * enabled, i_blocks from cached attr may not be accurate.
533 */
534 if (!err && fm->fc->writeback_cache)
535 fuse_invalidate_attr_mask(inode, STATX_BLOCKS);
536 return err;
537 }
538
fuse_fsync_common(struct file * file,loff_t start,loff_t end,int datasync,int opcode)539 int fuse_fsync_common(struct file *file, loff_t start, loff_t end,
540 int datasync, int opcode)
541 {
542 struct inode *inode = file->f_mapping->host;
543 struct fuse_mount *fm = get_fuse_mount(inode);
544 struct fuse_file *ff = file->private_data;
545 FUSE_ARGS(args);
546 struct fuse_fsync_in inarg;
547
548 memset(&inarg, 0, sizeof(inarg));
549 inarg.fh = ff->fh;
550 inarg.fsync_flags = datasync ? FUSE_FSYNC_FDATASYNC : 0;
551 args.opcode = opcode;
552 args.nodeid = get_node_id(inode);
553 args.in_numargs = 1;
554 args.in_args[0].size = sizeof(inarg);
555 args.in_args[0].value = &inarg;
556 return fuse_simple_request(fm, &args);
557 }
558
fuse_fsync(struct file * file,loff_t start,loff_t end,int datasync)559 static int fuse_fsync(struct file *file, loff_t start, loff_t end,
560 int datasync)
561 {
562 struct inode *inode = file->f_mapping->host;
563 struct fuse_conn *fc = get_fuse_conn(inode);
564 int err;
565
566 if (fuse_is_bad(inode))
567 return -EIO;
568
569 inode_lock(inode);
570
571 /*
572 * Start writeback against all dirty pages of the inode, then
573 * wait for all outstanding writes, before sending the FSYNC
574 * request.
575 */
576 err = file_write_and_wait_range(file, start, end);
577 if (err)
578 goto out;
579
580 fuse_sync_writes(inode);
581
582 /*
583 * Due to implementation of fuse writeback
584 * file_write_and_wait_range() does not catch errors.
585 * We have to do this directly after fuse_sync_writes()
586 */
587 err = file_check_and_advance_wb_err(file);
588 if (err)
589 goto out;
590
591 err = sync_inode_metadata(inode, 1);
592 if (err)
593 goto out;
594
595 if (fc->no_fsync)
596 goto out;
597
598 err = fuse_fsync_common(file, start, end, datasync, FUSE_FSYNC);
599 if (err == -ENOSYS) {
600 fc->no_fsync = 1;
601 err = 0;
602 }
603 out:
604 inode_unlock(inode);
605
606 return err;
607 }
608
fuse_read_args_fill(struct fuse_io_args * ia,struct file * file,loff_t pos,size_t count,int opcode)609 void fuse_read_args_fill(struct fuse_io_args *ia, struct file *file, loff_t pos,
610 size_t count, int opcode)
611 {
612 struct fuse_file *ff = file->private_data;
613 struct fuse_args *args = &ia->ap.args;
614
615 ia->read.in.fh = ff->fh;
616 ia->read.in.offset = pos;
617 ia->read.in.size = count;
618 ia->read.in.flags = file->f_flags;
619 args->opcode = opcode;
620 args->nodeid = ff->nodeid;
621 args->in_numargs = 1;
622 args->in_args[0].size = sizeof(ia->read.in);
623 args->in_args[0].value = &ia->read.in;
624 args->out_argvar = true;
625 args->out_numargs = 1;
626 args->out_args[0].size = count;
627 }
628
fuse_release_user_pages(struct fuse_args_pages * ap,bool should_dirty)629 static void fuse_release_user_pages(struct fuse_args_pages *ap,
630 bool should_dirty)
631 {
632 unsigned int i;
633
634 for (i = 0; i < ap->num_pages; i++) {
635 if (should_dirty)
636 set_page_dirty_lock(ap->pages[i]);
637 put_page(ap->pages[i]);
638 }
639 }
640
fuse_io_release(struct kref * kref)641 static void fuse_io_release(struct kref *kref)
642 {
643 kfree(container_of(kref, struct fuse_io_priv, refcnt));
644 }
645
fuse_get_res_by_io(struct fuse_io_priv * io)646 static ssize_t fuse_get_res_by_io(struct fuse_io_priv *io)
647 {
648 if (io->err)
649 return io->err;
650
651 if (io->bytes >= 0 && io->write)
652 return -EIO;
653
654 return io->bytes < 0 ? io->size : io->bytes;
655 }
656
657 /*
658 * In case of short read, the caller sets 'pos' to the position of
659 * actual end of fuse request in IO request. Otherwise, if bytes_requested
660 * == bytes_transferred or rw == WRITE, the caller sets 'pos' to -1.
661 *
662 * An example:
663 * User requested DIO read of 64K. It was split into two 32K fuse requests,
664 * both submitted asynchronously. The first of them was ACKed by userspace as
665 * fully completed (req->out.args[0].size == 32K) resulting in pos == -1. The
666 * second request was ACKed as short, e.g. only 1K was read, resulting in
667 * pos == 33K.
668 *
669 * Thus, when all fuse requests are completed, the minimal non-negative 'pos'
670 * will be equal to the length of the longest contiguous fragment of
671 * transferred data starting from the beginning of IO request.
672 */
fuse_aio_complete(struct fuse_io_priv * io,int err,ssize_t pos)673 static void fuse_aio_complete(struct fuse_io_priv *io, int err, ssize_t pos)
674 {
675 int left;
676
677 spin_lock(&io->lock);
678 if (err)
679 io->err = io->err ? : err;
680 else if (pos >= 0 && (io->bytes < 0 || pos < io->bytes))
681 io->bytes = pos;
682
683 left = --io->reqs;
684 if (!left && io->blocking)
685 complete(io->done);
686 spin_unlock(&io->lock);
687
688 if (!left && !io->blocking) {
689 ssize_t res = fuse_get_res_by_io(io);
690
691 if (res >= 0) {
692 struct inode *inode = file_inode(io->iocb->ki_filp);
693 struct fuse_conn *fc = get_fuse_conn(inode);
694 struct fuse_inode *fi = get_fuse_inode(inode);
695
696 spin_lock(&fi->lock);
697 fi->attr_version = atomic64_inc_return(&fc->attr_version);
698 spin_unlock(&fi->lock);
699 }
700
701 io->iocb->ki_complete(io->iocb, res);
702 }
703
704 kref_put(&io->refcnt, fuse_io_release);
705 }
706
fuse_io_alloc(struct fuse_io_priv * io,unsigned int npages)707 static struct fuse_io_args *fuse_io_alloc(struct fuse_io_priv *io,
708 unsigned int npages)
709 {
710 struct fuse_io_args *ia;
711
712 ia = kzalloc(sizeof(*ia), GFP_KERNEL);
713 if (ia) {
714 ia->io = io;
715 ia->ap.pages = fuse_pages_alloc(npages, GFP_KERNEL,
716 &ia->ap.descs);
717 if (!ia->ap.pages) {
718 kfree(ia);
719 ia = NULL;
720 }
721 }
722 return ia;
723 }
724
fuse_io_free(struct fuse_io_args * ia)725 static void fuse_io_free(struct fuse_io_args *ia)
726 {
727 kfree(ia->ap.pages);
728 kfree(ia);
729 }
730
fuse_aio_complete_req(struct fuse_mount * fm,struct fuse_args * args,int err)731 static void fuse_aio_complete_req(struct fuse_mount *fm, struct fuse_args *args,
732 int err)
733 {
734 struct fuse_io_args *ia = container_of(args, typeof(*ia), ap.args);
735 struct fuse_io_priv *io = ia->io;
736 ssize_t pos = -1;
737
738 fuse_release_user_pages(&ia->ap, io->should_dirty);
739
740 if (err) {
741 /* Nothing */
742 } else if (io->write) {
743 if (ia->write.out.size > ia->write.in.size) {
744 err = -EIO;
745 } else if (ia->write.in.size != ia->write.out.size) {
746 pos = ia->write.in.offset - io->offset +
747 ia->write.out.size;
748 }
749 } else {
750 u32 outsize = args->out_args[0].size;
751
752 if (ia->read.in.size != outsize)
753 pos = ia->read.in.offset - io->offset + outsize;
754 }
755
756 fuse_aio_complete(io, err, pos);
757 fuse_io_free(ia);
758 }
759
fuse_async_req_send(struct fuse_mount * fm,struct fuse_io_args * ia,size_t num_bytes)760 static ssize_t fuse_async_req_send(struct fuse_mount *fm,
761 struct fuse_io_args *ia, size_t num_bytes)
762 {
763 ssize_t err;
764 struct fuse_io_priv *io = ia->io;
765
766 spin_lock(&io->lock);
767 kref_get(&io->refcnt);
768 io->size += num_bytes;
769 io->reqs++;
770 spin_unlock(&io->lock);
771
772 ia->ap.args.end = fuse_aio_complete_req;
773 ia->ap.args.may_block = io->should_dirty;
774 err = fuse_simple_background(fm, &ia->ap.args, GFP_KERNEL);
775 if (err)
776 fuse_aio_complete_req(fm, &ia->ap.args, err);
777
778 return num_bytes;
779 }
780
fuse_send_read(struct fuse_io_args * ia,loff_t pos,size_t count,fl_owner_t owner)781 static ssize_t fuse_send_read(struct fuse_io_args *ia, loff_t pos, size_t count,
782 fl_owner_t owner)
783 {
784 struct file *file = ia->io->iocb->ki_filp;
785 struct fuse_file *ff = file->private_data;
786 struct fuse_mount *fm = ff->fm;
787
788 fuse_read_args_fill(ia, file, pos, count, FUSE_READ);
789 if (owner != NULL) {
790 ia->read.in.read_flags |= FUSE_READ_LOCKOWNER;
791 ia->read.in.lock_owner = fuse_lock_owner_id(fm->fc, owner);
792 }
793
794 if (ia->io->async)
795 return fuse_async_req_send(fm, ia, count);
796
797 return fuse_simple_request(fm, &ia->ap.args);
798 }
799
fuse_read_update_size(struct inode * inode,loff_t size,u64 attr_ver)800 static void fuse_read_update_size(struct inode *inode, loff_t size,
801 u64 attr_ver)
802 {
803 struct fuse_conn *fc = get_fuse_conn(inode);
804 struct fuse_inode *fi = get_fuse_inode(inode);
805
806 spin_lock(&fi->lock);
807 if (attr_ver >= fi->attr_version && size < inode->i_size &&
808 !test_bit(FUSE_I_SIZE_UNSTABLE, &fi->state)) {
809 fi->attr_version = atomic64_inc_return(&fc->attr_version);
810 i_size_write(inode, size);
811 }
812 spin_unlock(&fi->lock);
813 }
814
fuse_short_read(struct inode * inode,u64 attr_ver,size_t num_read,struct fuse_args_pages * ap)815 static void fuse_short_read(struct inode *inode, u64 attr_ver, size_t num_read,
816 struct fuse_args_pages *ap)
817 {
818 struct fuse_conn *fc = get_fuse_conn(inode);
819
820 /*
821 * If writeback_cache is enabled, a short read means there's a hole in
822 * the file. Some data after the hole is in page cache, but has not
823 * reached the client fs yet. So the hole is not present there.
824 */
825 if (!fc->writeback_cache) {
826 loff_t pos = page_offset(ap->pages[0]) + num_read;
827 fuse_read_update_size(inode, pos, attr_ver);
828 }
829 }
830
fuse_do_readpage(struct file * file,struct page * page)831 static int fuse_do_readpage(struct file *file, struct page *page)
832 {
833 struct inode *inode = page->mapping->host;
834 struct fuse_mount *fm = get_fuse_mount(inode);
835 loff_t pos = page_offset(page);
836 struct fuse_page_desc desc = { .length = PAGE_SIZE };
837 struct fuse_io_args ia = {
838 .ap.args.page_zeroing = true,
839 .ap.args.out_pages = true,
840 .ap.num_pages = 1,
841 .ap.pages = &page,
842 .ap.descs = &desc,
843 };
844 ssize_t res;
845 u64 attr_ver;
846
847 /*
848 * Page writeback can extend beyond the lifetime of the
849 * page-cache page, so make sure we read a properly synced
850 * page.
851 */
852 fuse_wait_on_page_writeback(inode, page->index);
853
854 attr_ver = fuse_get_attr_version(fm->fc);
855
856 /* Don't overflow end offset */
857 if (pos + (desc.length - 1) == LLONG_MAX)
858 desc.length--;
859
860 fuse_read_args_fill(&ia, file, pos, desc.length, FUSE_READ);
861 res = fuse_simple_request(fm, &ia.ap.args);
862 if (res < 0)
863 return res;
864 /*
865 * Short read means EOF. If file size is larger, truncate it
866 */
867 if (res < desc.length)
868 fuse_short_read(inode, attr_ver, res, &ia.ap);
869
870 SetPageUptodate(page);
871
872 return 0;
873 }
874
fuse_read_folio(struct file * file,struct folio * folio)875 static int fuse_read_folio(struct file *file, struct folio *folio)
876 {
877 struct page *page = &folio->page;
878 struct inode *inode = page->mapping->host;
879 int err;
880
881 err = -EIO;
882 if (fuse_is_bad(inode))
883 goto out;
884
885 err = fuse_do_readpage(file, page);
886 fuse_invalidate_atime(inode);
887 out:
888 unlock_page(page);
889 return err;
890 }
891
fuse_readpages_end(struct fuse_mount * fm,struct fuse_args * args,int err)892 static void fuse_readpages_end(struct fuse_mount *fm, struct fuse_args *args,
893 int err)
894 {
895 int i;
896 struct fuse_io_args *ia = container_of(args, typeof(*ia), ap.args);
897 struct fuse_args_pages *ap = &ia->ap;
898 size_t count = ia->read.in.size;
899 size_t num_read = args->out_args[0].size;
900 struct address_space *mapping = NULL;
901
902 for (i = 0; mapping == NULL && i < ap->num_pages; i++)
903 mapping = ap->pages[i]->mapping;
904
905 if (mapping) {
906 struct inode *inode = mapping->host;
907
908 /*
909 * Short read means EOF. If file size is larger, truncate it
910 */
911 if (!err && num_read < count)
912 fuse_short_read(inode, ia->read.attr_ver, num_read, ap);
913
914 fuse_invalidate_atime(inode);
915 }
916
917 for (i = 0; i < ap->num_pages; i++) {
918 struct page *page = ap->pages[i];
919
920 if (!err)
921 SetPageUptodate(page);
922 else
923 SetPageError(page);
924 unlock_page(page);
925 put_page(page);
926 }
927 if (ia->ff)
928 fuse_file_put(ia->ff, false, false);
929
930 fuse_io_free(ia);
931 }
932
fuse_send_readpages(struct fuse_io_args * ia,struct file * file)933 static void fuse_send_readpages(struct fuse_io_args *ia, struct file *file)
934 {
935 struct fuse_file *ff = file->private_data;
936 struct fuse_mount *fm = ff->fm;
937 struct fuse_args_pages *ap = &ia->ap;
938 loff_t pos = page_offset(ap->pages[0]);
939 size_t count = ap->num_pages << PAGE_SHIFT;
940 ssize_t res;
941 int err;
942
943 ap->args.out_pages = true;
944 ap->args.page_zeroing = true;
945 ap->args.page_replace = true;
946
947 /* Don't overflow end offset */
948 if (pos + (count - 1) == LLONG_MAX) {
949 count--;
950 ap->descs[ap->num_pages - 1].length--;
951 }
952 WARN_ON((loff_t) (pos + count) < 0);
953
954 fuse_read_args_fill(ia, file, pos, count, FUSE_READ);
955 ia->read.attr_ver = fuse_get_attr_version(fm->fc);
956 if (fm->fc->async_read) {
957 ia->ff = fuse_file_get(ff);
958 ap->args.end = fuse_readpages_end;
959 err = fuse_simple_background(fm, &ap->args, GFP_KERNEL);
960 if (!err)
961 return;
962 } else {
963 res = fuse_simple_request(fm, &ap->args);
964 err = res < 0 ? res : 0;
965 }
966 fuse_readpages_end(fm, &ap->args, err);
967 }
968
fuse_readahead(struct readahead_control * rac)969 static void fuse_readahead(struct readahead_control *rac)
970 {
971 struct inode *inode = rac->mapping->host;
972 struct fuse_conn *fc = get_fuse_conn(inode);
973 unsigned int i, max_pages, nr_pages = 0;
974
975 if (fuse_is_bad(inode))
976 return;
977
978 max_pages = min_t(unsigned int, fc->max_pages,
979 fc->max_read / PAGE_SIZE);
980
981 for (;;) {
982 struct fuse_io_args *ia;
983 struct fuse_args_pages *ap;
984
985 if (fc->num_background >= fc->congestion_threshold &&
986 rac->ra->async_size >= readahead_count(rac))
987 /*
988 * Congested and only async pages left, so skip the
989 * rest.
990 */
991 break;
992
993 nr_pages = readahead_count(rac) - nr_pages;
994 if (nr_pages > max_pages)
995 nr_pages = max_pages;
996 if (nr_pages == 0)
997 break;
998 ia = fuse_io_alloc(NULL, nr_pages);
999 if (!ia)
1000 return;
1001 ap = &ia->ap;
1002 nr_pages = __readahead_batch(rac, ap->pages, nr_pages);
1003 for (i = 0; i < nr_pages; i++) {
1004 fuse_wait_on_page_writeback(inode,
1005 readahead_index(rac) + i);
1006 ap->descs[i].length = PAGE_SIZE;
1007 }
1008 ap->num_pages = nr_pages;
1009 fuse_send_readpages(ia, rac->file);
1010 }
1011 }
1012
fuse_cache_read_iter(struct kiocb * iocb,struct iov_iter * to)1013 static ssize_t fuse_cache_read_iter(struct kiocb *iocb, struct iov_iter *to)
1014 {
1015 struct inode *inode = iocb->ki_filp->f_mapping->host;
1016 struct fuse_conn *fc = get_fuse_conn(inode);
1017
1018 /*
1019 * In auto invalidate mode, always update attributes on read.
1020 * Otherwise, only update if we attempt to read past EOF (to ensure
1021 * i_size is up to date).
1022 */
1023 if (fc->auto_inval_data ||
1024 (iocb->ki_pos + iov_iter_count(to) > i_size_read(inode))) {
1025 int err;
1026 err = fuse_update_attributes(inode, iocb->ki_filp, STATX_SIZE);
1027 if (err)
1028 return err;
1029 }
1030
1031 return generic_file_read_iter(iocb, to);
1032 }
1033
fuse_write_args_fill(struct fuse_io_args * ia,struct fuse_file * ff,loff_t pos,size_t count)1034 static void fuse_write_args_fill(struct fuse_io_args *ia, struct fuse_file *ff,
1035 loff_t pos, size_t count)
1036 {
1037 struct fuse_args *args = &ia->ap.args;
1038
1039 ia->write.in.fh = ff->fh;
1040 ia->write.in.offset = pos;
1041 ia->write.in.size = count;
1042 args->opcode = FUSE_WRITE;
1043 args->nodeid = ff->nodeid;
1044 args->in_numargs = 2;
1045 if (ff->fm->fc->minor < 9)
1046 args->in_args[0].size = FUSE_COMPAT_WRITE_IN_SIZE;
1047 else
1048 args->in_args[0].size = sizeof(ia->write.in);
1049 args->in_args[0].value = &ia->write.in;
1050 args->in_args[1].size = count;
1051 args->out_numargs = 1;
1052 args->out_args[0].size = sizeof(ia->write.out);
1053 args->out_args[0].value = &ia->write.out;
1054 }
1055
fuse_write_flags(struct kiocb * iocb)1056 static unsigned int fuse_write_flags(struct kiocb *iocb)
1057 {
1058 unsigned int flags = iocb->ki_filp->f_flags;
1059
1060 if (iocb_is_dsync(iocb))
1061 flags |= O_DSYNC;
1062 if (iocb->ki_flags & IOCB_SYNC)
1063 flags |= O_SYNC;
1064
1065 return flags;
1066 }
1067
fuse_send_write(struct fuse_io_args * ia,loff_t pos,size_t count,fl_owner_t owner)1068 static ssize_t fuse_send_write(struct fuse_io_args *ia, loff_t pos,
1069 size_t count, fl_owner_t owner)
1070 {
1071 struct kiocb *iocb = ia->io->iocb;
1072 struct file *file = iocb->ki_filp;
1073 struct fuse_file *ff = file->private_data;
1074 struct fuse_mount *fm = ff->fm;
1075 struct fuse_write_in *inarg = &ia->write.in;
1076 ssize_t err;
1077
1078 fuse_write_args_fill(ia, ff, pos, count);
1079 inarg->flags = fuse_write_flags(iocb);
1080 if (owner != NULL) {
1081 inarg->write_flags |= FUSE_WRITE_LOCKOWNER;
1082 inarg->lock_owner = fuse_lock_owner_id(fm->fc, owner);
1083 }
1084
1085 if (ia->io->async)
1086 return fuse_async_req_send(fm, ia, count);
1087
1088 err = fuse_simple_request(fm, &ia->ap.args);
1089 if (!err && ia->write.out.size > count)
1090 err = -EIO;
1091
1092 return err ?: ia->write.out.size;
1093 }
1094
fuse_write_update_attr(struct inode * inode,loff_t pos,ssize_t written)1095 bool fuse_write_update_attr(struct inode *inode, loff_t pos, ssize_t written)
1096 {
1097 struct fuse_conn *fc = get_fuse_conn(inode);
1098 struct fuse_inode *fi = get_fuse_inode(inode);
1099 bool ret = false;
1100
1101 spin_lock(&fi->lock);
1102 fi->attr_version = atomic64_inc_return(&fc->attr_version);
1103 if (written > 0 && pos > inode->i_size) {
1104 i_size_write(inode, pos);
1105 ret = true;
1106 }
1107 spin_unlock(&fi->lock);
1108
1109 fuse_invalidate_attr_mask(inode, FUSE_STATX_MODSIZE);
1110
1111 return ret;
1112 }
1113
fuse_send_write_pages(struct fuse_io_args * ia,struct kiocb * iocb,struct inode * inode,loff_t pos,size_t count)1114 static ssize_t fuse_send_write_pages(struct fuse_io_args *ia,
1115 struct kiocb *iocb, struct inode *inode,
1116 loff_t pos, size_t count)
1117 {
1118 struct fuse_args_pages *ap = &ia->ap;
1119 struct file *file = iocb->ki_filp;
1120 struct fuse_file *ff = file->private_data;
1121 struct fuse_mount *fm = ff->fm;
1122 unsigned int offset, i;
1123 bool short_write;
1124 int err;
1125
1126 for (i = 0; i < ap->num_pages; i++)
1127 fuse_wait_on_page_writeback(inode, ap->pages[i]->index);
1128
1129 fuse_write_args_fill(ia, ff, pos, count);
1130 ia->write.in.flags = fuse_write_flags(iocb);
1131 if (fm->fc->handle_killpriv_v2 && !capable(CAP_FSETID))
1132 ia->write.in.write_flags |= FUSE_WRITE_KILL_SUIDGID;
1133
1134 err = fuse_simple_request(fm, &ap->args);
1135 if (!err && ia->write.out.size > count)
1136 err = -EIO;
1137
1138 short_write = ia->write.out.size < count;
1139 offset = ap->descs[0].offset;
1140 count = ia->write.out.size;
1141 for (i = 0; i < ap->num_pages; i++) {
1142 struct page *page = ap->pages[i];
1143
1144 if (err) {
1145 ClearPageUptodate(page);
1146 } else {
1147 if (count >= PAGE_SIZE - offset)
1148 count -= PAGE_SIZE - offset;
1149 else {
1150 if (short_write)
1151 ClearPageUptodate(page);
1152 count = 0;
1153 }
1154 offset = 0;
1155 }
1156 if (ia->write.page_locked && (i == ap->num_pages - 1))
1157 unlock_page(page);
1158 put_page(page);
1159 }
1160
1161 return err;
1162 }
1163
fuse_fill_write_pages(struct fuse_io_args * ia,struct address_space * mapping,struct iov_iter * ii,loff_t pos,unsigned int max_pages)1164 static ssize_t fuse_fill_write_pages(struct fuse_io_args *ia,
1165 struct address_space *mapping,
1166 struct iov_iter *ii, loff_t pos,
1167 unsigned int max_pages)
1168 {
1169 struct fuse_args_pages *ap = &ia->ap;
1170 struct fuse_conn *fc = get_fuse_conn(mapping->host);
1171 unsigned offset = pos & (PAGE_SIZE - 1);
1172 size_t count = 0;
1173 int err;
1174
1175 ap->args.in_pages = true;
1176 ap->descs[0].offset = offset;
1177
1178 do {
1179 size_t tmp;
1180 struct page *page;
1181 pgoff_t index = pos >> PAGE_SHIFT;
1182 size_t bytes = min_t(size_t, PAGE_SIZE - offset,
1183 iov_iter_count(ii));
1184
1185 bytes = min_t(size_t, bytes, fc->max_write - count);
1186
1187 again:
1188 err = -EFAULT;
1189 if (fault_in_iov_iter_readable(ii, bytes))
1190 break;
1191
1192 err = -ENOMEM;
1193 page = grab_cache_page_write_begin(mapping, index);
1194 if (!page)
1195 break;
1196
1197 if (mapping_writably_mapped(mapping))
1198 flush_dcache_page(page);
1199
1200 tmp = copy_page_from_iter_atomic(page, offset, bytes, ii);
1201 flush_dcache_page(page);
1202
1203 if (!tmp) {
1204 unlock_page(page);
1205 put_page(page);
1206 goto again;
1207 }
1208
1209 err = 0;
1210 ap->pages[ap->num_pages] = page;
1211 ap->descs[ap->num_pages].length = tmp;
1212 ap->num_pages++;
1213
1214 count += tmp;
1215 pos += tmp;
1216 offset += tmp;
1217 if (offset == PAGE_SIZE)
1218 offset = 0;
1219
1220 /* If we copied full page, mark it uptodate */
1221 if (tmp == PAGE_SIZE)
1222 SetPageUptodate(page);
1223
1224 if (PageUptodate(page)) {
1225 unlock_page(page);
1226 } else {
1227 ia->write.page_locked = true;
1228 break;
1229 }
1230 if (!fc->big_writes)
1231 break;
1232 } while (iov_iter_count(ii) && count < fc->max_write &&
1233 ap->num_pages < max_pages && offset == 0);
1234
1235 return count > 0 ? count : err;
1236 }
1237
fuse_wr_pages(loff_t pos,size_t len,unsigned int max_pages)1238 static inline unsigned int fuse_wr_pages(loff_t pos, size_t len,
1239 unsigned int max_pages)
1240 {
1241 return min_t(unsigned int,
1242 ((pos + len - 1) >> PAGE_SHIFT) -
1243 (pos >> PAGE_SHIFT) + 1,
1244 max_pages);
1245 }
1246
fuse_perform_write(struct kiocb * iocb,struct iov_iter * ii)1247 static ssize_t fuse_perform_write(struct kiocb *iocb, struct iov_iter *ii)
1248 {
1249 struct address_space *mapping = iocb->ki_filp->f_mapping;
1250 struct inode *inode = mapping->host;
1251 struct fuse_conn *fc = get_fuse_conn(inode);
1252 struct fuse_inode *fi = get_fuse_inode(inode);
1253 loff_t pos = iocb->ki_pos;
1254 int err = 0;
1255 ssize_t res = 0;
1256
1257 if (inode->i_size < pos + iov_iter_count(ii))
1258 set_bit(FUSE_I_SIZE_UNSTABLE, &fi->state);
1259
1260 do {
1261 ssize_t count;
1262 struct fuse_io_args ia = {};
1263 struct fuse_args_pages *ap = &ia.ap;
1264 unsigned int nr_pages = fuse_wr_pages(pos, iov_iter_count(ii),
1265 fc->max_pages);
1266
1267 ap->pages = fuse_pages_alloc(nr_pages, GFP_KERNEL, &ap->descs);
1268 if (!ap->pages) {
1269 err = -ENOMEM;
1270 break;
1271 }
1272
1273 count = fuse_fill_write_pages(&ia, mapping, ii, pos, nr_pages);
1274 if (count <= 0) {
1275 err = count;
1276 } else {
1277 err = fuse_send_write_pages(&ia, iocb, inode,
1278 pos, count);
1279 if (!err) {
1280 size_t num_written = ia.write.out.size;
1281
1282 res += num_written;
1283 pos += num_written;
1284
1285 /* break out of the loop on short write */
1286 if (num_written != count)
1287 err = -EIO;
1288 }
1289 }
1290 kfree(ap->pages);
1291 } while (!err && iov_iter_count(ii));
1292
1293 fuse_write_update_attr(inode, pos, res);
1294 clear_bit(FUSE_I_SIZE_UNSTABLE, &fi->state);
1295
1296 if (!res)
1297 return err;
1298 iocb->ki_pos += res;
1299 return res;
1300 }
1301
fuse_cache_write_iter(struct kiocb * iocb,struct iov_iter * from)1302 static ssize_t fuse_cache_write_iter(struct kiocb *iocb, struct iov_iter *from)
1303 {
1304 struct file *file = iocb->ki_filp;
1305 struct address_space *mapping = file->f_mapping;
1306 ssize_t written = 0;
1307 struct inode *inode = mapping->host;
1308 ssize_t err;
1309 struct fuse_conn *fc = get_fuse_conn(inode);
1310
1311 if (fc->writeback_cache) {
1312 /* Update size (EOF optimization) and mode (SUID clearing) */
1313 err = fuse_update_attributes(mapping->host, file,
1314 STATX_SIZE | STATX_MODE);
1315 if (err)
1316 return err;
1317
1318 if (fc->handle_killpriv_v2 &&
1319 setattr_should_drop_suidgid(&nop_mnt_idmap,
1320 file_inode(file))) {
1321 goto writethrough;
1322 }
1323
1324 return generic_file_write_iter(iocb, from);
1325 }
1326
1327 writethrough:
1328 inode_lock(inode);
1329
1330 err = generic_write_checks(iocb, from);
1331 if (err <= 0)
1332 goto out;
1333
1334 err = file_remove_privs(file);
1335 if (err)
1336 goto out;
1337
1338 err = file_update_time(file);
1339 if (err)
1340 goto out;
1341
1342 if (iocb->ki_flags & IOCB_DIRECT) {
1343 written = generic_file_direct_write(iocb, from);
1344 if (written < 0 || !iov_iter_count(from))
1345 goto out;
1346 written = direct_write_fallback(iocb, from, written,
1347 fuse_perform_write(iocb, from));
1348 } else {
1349 written = fuse_perform_write(iocb, from);
1350 }
1351 out:
1352 inode_unlock(inode);
1353 if (written > 0)
1354 written = generic_write_sync(iocb, written);
1355
1356 return written ? written : err;
1357 }
1358
fuse_get_user_addr(const struct iov_iter * ii)1359 static inline unsigned long fuse_get_user_addr(const struct iov_iter *ii)
1360 {
1361 return (unsigned long)iter_iov(ii)->iov_base + ii->iov_offset;
1362 }
1363
fuse_get_frag_size(const struct iov_iter * ii,size_t max_size)1364 static inline size_t fuse_get_frag_size(const struct iov_iter *ii,
1365 size_t max_size)
1366 {
1367 return min(iov_iter_single_seg_count(ii), max_size);
1368 }
1369
fuse_get_user_pages(struct fuse_args_pages * ap,struct iov_iter * ii,size_t * nbytesp,int write,unsigned int max_pages)1370 static int fuse_get_user_pages(struct fuse_args_pages *ap, struct iov_iter *ii,
1371 size_t *nbytesp, int write,
1372 unsigned int max_pages)
1373 {
1374 size_t nbytes = 0; /* # bytes already packed in req */
1375 ssize_t ret = 0;
1376
1377 /* Special case for kernel I/O: can copy directly into the buffer */
1378 if (iov_iter_is_kvec(ii)) {
1379 unsigned long user_addr = fuse_get_user_addr(ii);
1380 size_t frag_size = fuse_get_frag_size(ii, *nbytesp);
1381
1382 if (write)
1383 ap->args.in_args[1].value = (void *) user_addr;
1384 else
1385 ap->args.out_args[0].value = (void *) user_addr;
1386
1387 iov_iter_advance(ii, frag_size);
1388 *nbytesp = frag_size;
1389 return 0;
1390 }
1391
1392 while (nbytes < *nbytesp && ap->num_pages < max_pages) {
1393 unsigned npages;
1394 size_t start;
1395 ret = iov_iter_get_pages2(ii, &ap->pages[ap->num_pages],
1396 *nbytesp - nbytes,
1397 max_pages - ap->num_pages,
1398 &start);
1399 if (ret < 0)
1400 break;
1401
1402 nbytes += ret;
1403
1404 ret += start;
1405 npages = DIV_ROUND_UP(ret, PAGE_SIZE);
1406
1407 ap->descs[ap->num_pages].offset = start;
1408 fuse_page_descs_length_init(ap->descs, ap->num_pages, npages);
1409
1410 ap->num_pages += npages;
1411 ap->descs[ap->num_pages - 1].length -=
1412 (PAGE_SIZE - ret) & (PAGE_SIZE - 1);
1413 }
1414
1415 ap->args.user_pages = true;
1416 if (write)
1417 ap->args.in_pages = true;
1418 else
1419 ap->args.out_pages = true;
1420
1421 *nbytesp = nbytes;
1422
1423 return ret < 0 ? ret : 0;
1424 }
1425
fuse_direct_io(struct fuse_io_priv * io,struct iov_iter * iter,loff_t * ppos,int flags)1426 ssize_t fuse_direct_io(struct fuse_io_priv *io, struct iov_iter *iter,
1427 loff_t *ppos, int flags)
1428 {
1429 int write = flags & FUSE_DIO_WRITE;
1430 int cuse = flags & FUSE_DIO_CUSE;
1431 struct file *file = io->iocb->ki_filp;
1432 struct address_space *mapping = file->f_mapping;
1433 struct inode *inode = mapping->host;
1434 struct fuse_file *ff = file->private_data;
1435 struct fuse_conn *fc = ff->fm->fc;
1436 size_t nmax = write ? fc->max_write : fc->max_read;
1437 loff_t pos = *ppos;
1438 size_t count = iov_iter_count(iter);
1439 pgoff_t idx_from = pos >> PAGE_SHIFT;
1440 pgoff_t idx_to = (pos + count - 1) >> PAGE_SHIFT;
1441 ssize_t res = 0;
1442 int err = 0;
1443 struct fuse_io_args *ia;
1444 unsigned int max_pages;
1445 bool fopen_direct_io = ff->open_flags & FOPEN_DIRECT_IO;
1446
1447 max_pages = iov_iter_npages(iter, fc->max_pages);
1448 ia = fuse_io_alloc(io, max_pages);
1449 if (!ia)
1450 return -ENOMEM;
1451
1452 if (fopen_direct_io && fc->direct_io_allow_mmap) {
1453 res = filemap_write_and_wait_range(mapping, pos, pos + count - 1);
1454 if (res) {
1455 fuse_io_free(ia);
1456 return res;
1457 }
1458 }
1459 if (!cuse && fuse_range_is_writeback(inode, idx_from, idx_to)) {
1460 if (!write)
1461 inode_lock(inode);
1462 fuse_sync_writes(inode);
1463 if (!write)
1464 inode_unlock(inode);
1465 }
1466
1467 if (fopen_direct_io && write) {
1468 res = invalidate_inode_pages2_range(mapping, idx_from, idx_to);
1469 if (res) {
1470 fuse_io_free(ia);
1471 return res;
1472 }
1473 }
1474
1475 io->should_dirty = !write && user_backed_iter(iter);
1476 while (count) {
1477 ssize_t nres;
1478 fl_owner_t owner = current->files;
1479 size_t nbytes = min(count, nmax);
1480
1481 err = fuse_get_user_pages(&ia->ap, iter, &nbytes, write,
1482 max_pages);
1483 if (err && !nbytes)
1484 break;
1485
1486 if (write) {
1487 if (!capable(CAP_FSETID))
1488 ia->write.in.write_flags |= FUSE_WRITE_KILL_SUIDGID;
1489
1490 nres = fuse_send_write(ia, pos, nbytes, owner);
1491 } else {
1492 nres = fuse_send_read(ia, pos, nbytes, owner);
1493 }
1494
1495 if (!io->async || nres < 0) {
1496 fuse_release_user_pages(&ia->ap, io->should_dirty);
1497 fuse_io_free(ia);
1498 }
1499 ia = NULL;
1500 if (nres < 0) {
1501 iov_iter_revert(iter, nbytes);
1502 err = nres;
1503 break;
1504 }
1505 WARN_ON(nres > nbytes);
1506
1507 count -= nres;
1508 res += nres;
1509 pos += nres;
1510 if (nres != nbytes) {
1511 iov_iter_revert(iter, nbytes - nres);
1512 break;
1513 }
1514 if (count) {
1515 max_pages = iov_iter_npages(iter, fc->max_pages);
1516 ia = fuse_io_alloc(io, max_pages);
1517 if (!ia)
1518 break;
1519 }
1520 }
1521 if (ia)
1522 fuse_io_free(ia);
1523 if (res > 0)
1524 *ppos = pos;
1525
1526 return res > 0 ? res : err;
1527 }
1528 EXPORT_SYMBOL_GPL(fuse_direct_io);
1529
__fuse_direct_read(struct fuse_io_priv * io,struct iov_iter * iter,loff_t * ppos)1530 static ssize_t __fuse_direct_read(struct fuse_io_priv *io,
1531 struct iov_iter *iter,
1532 loff_t *ppos)
1533 {
1534 ssize_t res;
1535 struct inode *inode = file_inode(io->iocb->ki_filp);
1536
1537 res = fuse_direct_io(io, iter, ppos, 0);
1538
1539 fuse_invalidate_atime(inode);
1540
1541 return res;
1542 }
1543
1544 static ssize_t fuse_direct_IO(struct kiocb *iocb, struct iov_iter *iter);
1545
fuse_direct_read_iter(struct kiocb * iocb,struct iov_iter * to)1546 static ssize_t fuse_direct_read_iter(struct kiocb *iocb, struct iov_iter *to)
1547 {
1548 ssize_t res;
1549
1550 if (!is_sync_kiocb(iocb) && iocb->ki_flags & IOCB_DIRECT) {
1551 res = fuse_direct_IO(iocb, to);
1552 } else {
1553 struct fuse_io_priv io = FUSE_IO_PRIV_SYNC(iocb);
1554
1555 res = __fuse_direct_read(&io, to, &iocb->ki_pos);
1556 }
1557
1558 return res;
1559 }
1560
fuse_direct_write_extending_i_size(struct kiocb * iocb,struct iov_iter * iter)1561 static bool fuse_direct_write_extending_i_size(struct kiocb *iocb,
1562 struct iov_iter *iter)
1563 {
1564 struct inode *inode = file_inode(iocb->ki_filp);
1565
1566 return iocb->ki_pos + iov_iter_count(iter) > i_size_read(inode);
1567 }
1568
fuse_direct_write_iter(struct kiocb * iocb,struct iov_iter * from)1569 static ssize_t fuse_direct_write_iter(struct kiocb *iocb, struct iov_iter *from)
1570 {
1571 struct inode *inode = file_inode(iocb->ki_filp);
1572 struct file *file = iocb->ki_filp;
1573 struct fuse_file *ff = file->private_data;
1574 struct fuse_io_priv io = FUSE_IO_PRIV_SYNC(iocb);
1575 ssize_t res;
1576 bool exclusive_lock =
1577 !(ff->open_flags & FOPEN_PARALLEL_DIRECT_WRITES) ||
1578 get_fuse_conn(inode)->direct_io_allow_mmap ||
1579 iocb->ki_flags & IOCB_APPEND ||
1580 fuse_direct_write_extending_i_size(iocb, from);
1581
1582 /*
1583 * Take exclusive lock if
1584 * - Parallel direct writes are disabled - a user space decision
1585 * - Parallel direct writes are enabled and i_size is being extended.
1586 * - Shared mmap on direct_io file is supported (FUSE_DIRECT_IO_ALLOW_MMAP).
1587 * This might not be needed at all, but needs further investigation.
1588 */
1589 if (exclusive_lock)
1590 inode_lock(inode);
1591 else {
1592 inode_lock_shared(inode);
1593
1594 /* A race with truncate might have come up as the decision for
1595 * the lock type was done without holding the lock, check again.
1596 */
1597 if (fuse_direct_write_extending_i_size(iocb, from)) {
1598 inode_unlock_shared(inode);
1599 inode_lock(inode);
1600 exclusive_lock = true;
1601 }
1602 }
1603
1604 res = generic_write_checks(iocb, from);
1605 if (res > 0) {
1606 if (!is_sync_kiocb(iocb) && iocb->ki_flags & IOCB_DIRECT) {
1607 res = fuse_direct_IO(iocb, from);
1608 } else {
1609 res = fuse_direct_io(&io, from, &iocb->ki_pos,
1610 FUSE_DIO_WRITE);
1611 fuse_write_update_attr(inode, iocb->ki_pos, res);
1612 }
1613 }
1614 if (exclusive_lock)
1615 inode_unlock(inode);
1616 else
1617 inode_unlock_shared(inode);
1618
1619 return res;
1620 }
1621
fuse_file_read_iter(struct kiocb * iocb,struct iov_iter * to)1622 static ssize_t fuse_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
1623 {
1624 struct file *file = iocb->ki_filp;
1625 struct fuse_file *ff = file->private_data;
1626 struct inode *inode = file_inode(file);
1627
1628 if (fuse_is_bad(inode))
1629 return -EIO;
1630
1631 if (FUSE_IS_DAX(inode))
1632 return fuse_dax_read_iter(iocb, to);
1633
1634 if (!(ff->open_flags & FOPEN_DIRECT_IO))
1635 return fuse_cache_read_iter(iocb, to);
1636 else
1637 return fuse_direct_read_iter(iocb, to);
1638 }
1639
fuse_file_write_iter(struct kiocb * iocb,struct iov_iter * from)1640 static ssize_t fuse_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
1641 {
1642 struct file *file = iocb->ki_filp;
1643 struct fuse_file *ff = file->private_data;
1644 struct inode *inode = file_inode(file);
1645
1646 if (fuse_is_bad(inode))
1647 return -EIO;
1648
1649 if (FUSE_IS_DAX(inode))
1650 return fuse_dax_write_iter(iocb, from);
1651
1652 if (!(ff->open_flags & FOPEN_DIRECT_IO))
1653 return fuse_cache_write_iter(iocb, from);
1654 else
1655 return fuse_direct_write_iter(iocb, from);
1656 }
1657
fuse_writepage_free(struct fuse_writepage_args * wpa)1658 static void fuse_writepage_free(struct fuse_writepage_args *wpa)
1659 {
1660 struct fuse_args_pages *ap = &wpa->ia.ap;
1661 int i;
1662
1663 if (wpa->bucket)
1664 fuse_sync_bucket_dec(wpa->bucket);
1665
1666 for (i = 0; i < ap->num_pages; i++)
1667 __free_page(ap->pages[i]);
1668
1669 if (wpa->ia.ff)
1670 fuse_file_put(wpa->ia.ff, false, false);
1671
1672 kfree(ap->pages);
1673 kfree(wpa);
1674 }
1675
fuse_writepage_finish(struct fuse_mount * fm,struct fuse_writepage_args * wpa)1676 static void fuse_writepage_finish(struct fuse_mount *fm,
1677 struct fuse_writepage_args *wpa)
1678 {
1679 struct fuse_args_pages *ap = &wpa->ia.ap;
1680 struct inode *inode = wpa->inode;
1681 struct fuse_inode *fi = get_fuse_inode(inode);
1682 struct backing_dev_info *bdi = inode_to_bdi(inode);
1683 int i;
1684
1685 for (i = 0; i < ap->num_pages; i++) {
1686 dec_wb_stat(&bdi->wb, WB_WRITEBACK);
1687 dec_node_page_state(ap->pages[i], NR_WRITEBACK_TEMP);
1688 wb_writeout_inc(&bdi->wb);
1689 }
1690 wake_up(&fi->page_waitq);
1691 }
1692
1693 /* Called under fi->lock, may release and reacquire it */
fuse_send_writepage(struct fuse_mount * fm,struct fuse_writepage_args * wpa,loff_t size)1694 static void fuse_send_writepage(struct fuse_mount *fm,
1695 struct fuse_writepage_args *wpa, loff_t size)
1696 __releases(fi->lock)
1697 __acquires(fi->lock)
1698 {
1699 struct fuse_writepage_args *aux, *next;
1700 struct fuse_inode *fi = get_fuse_inode(wpa->inode);
1701 struct fuse_write_in *inarg = &wpa->ia.write.in;
1702 struct fuse_args *args = &wpa->ia.ap.args;
1703 __u64 data_size = wpa->ia.ap.num_pages * PAGE_SIZE;
1704 int err;
1705
1706 fi->writectr++;
1707 if (inarg->offset + data_size <= size) {
1708 inarg->size = data_size;
1709 } else if (inarg->offset < size) {
1710 inarg->size = size - inarg->offset;
1711 } else {
1712 /* Got truncated off completely */
1713 goto out_free;
1714 }
1715
1716 args->in_args[1].size = inarg->size;
1717 args->force = true;
1718 args->nocreds = true;
1719
1720 err = fuse_simple_background(fm, args, GFP_ATOMIC);
1721 if (err == -ENOMEM) {
1722 spin_unlock(&fi->lock);
1723 err = fuse_simple_background(fm, args, GFP_NOFS | __GFP_NOFAIL);
1724 spin_lock(&fi->lock);
1725 }
1726
1727 /* Fails on broken connection only */
1728 if (unlikely(err))
1729 goto out_free;
1730
1731 return;
1732
1733 out_free:
1734 fi->writectr--;
1735 rb_erase(&wpa->writepages_entry, &fi->writepages);
1736 fuse_writepage_finish(fm, wpa);
1737 spin_unlock(&fi->lock);
1738
1739 /* After fuse_writepage_finish() aux request list is private */
1740 for (aux = wpa->next; aux; aux = next) {
1741 next = aux->next;
1742 aux->next = NULL;
1743 fuse_writepage_free(aux);
1744 }
1745
1746 fuse_writepage_free(wpa);
1747 spin_lock(&fi->lock);
1748 }
1749
1750 /*
1751 * If fi->writectr is positive (no truncate or fsync going on) send
1752 * all queued writepage requests.
1753 *
1754 * Called with fi->lock
1755 */
fuse_flush_writepages(struct inode * inode)1756 void fuse_flush_writepages(struct inode *inode)
1757 __releases(fi->lock)
1758 __acquires(fi->lock)
1759 {
1760 struct fuse_mount *fm = get_fuse_mount(inode);
1761 struct fuse_inode *fi = get_fuse_inode(inode);
1762 loff_t crop = i_size_read(inode);
1763 struct fuse_writepage_args *wpa;
1764
1765 while (fi->writectr >= 0 && !list_empty(&fi->queued_writes)) {
1766 wpa = list_entry(fi->queued_writes.next,
1767 struct fuse_writepage_args, queue_entry);
1768 list_del_init(&wpa->queue_entry);
1769 fuse_send_writepage(fm, wpa, crop);
1770 }
1771 }
1772
fuse_insert_writeback(struct rb_root * root,struct fuse_writepage_args * wpa)1773 static struct fuse_writepage_args *fuse_insert_writeback(struct rb_root *root,
1774 struct fuse_writepage_args *wpa)
1775 {
1776 pgoff_t idx_from = wpa->ia.write.in.offset >> PAGE_SHIFT;
1777 pgoff_t idx_to = idx_from + wpa->ia.ap.num_pages - 1;
1778 struct rb_node **p = &root->rb_node;
1779 struct rb_node *parent = NULL;
1780
1781 WARN_ON(!wpa->ia.ap.num_pages);
1782 while (*p) {
1783 struct fuse_writepage_args *curr;
1784 pgoff_t curr_index;
1785
1786 parent = *p;
1787 curr = rb_entry(parent, struct fuse_writepage_args,
1788 writepages_entry);
1789 WARN_ON(curr->inode != wpa->inode);
1790 curr_index = curr->ia.write.in.offset >> PAGE_SHIFT;
1791
1792 if (idx_from >= curr_index + curr->ia.ap.num_pages)
1793 p = &(*p)->rb_right;
1794 else if (idx_to < curr_index)
1795 p = &(*p)->rb_left;
1796 else
1797 return curr;
1798 }
1799
1800 rb_link_node(&wpa->writepages_entry, parent, p);
1801 rb_insert_color(&wpa->writepages_entry, root);
1802 return NULL;
1803 }
1804
tree_insert(struct rb_root * root,struct fuse_writepage_args * wpa)1805 static void tree_insert(struct rb_root *root, struct fuse_writepage_args *wpa)
1806 {
1807 WARN_ON(fuse_insert_writeback(root, wpa));
1808 }
1809
fuse_writepage_end(struct fuse_mount * fm,struct fuse_args * args,int error)1810 static void fuse_writepage_end(struct fuse_mount *fm, struct fuse_args *args,
1811 int error)
1812 {
1813 struct fuse_writepage_args *wpa =
1814 container_of(args, typeof(*wpa), ia.ap.args);
1815 struct inode *inode = wpa->inode;
1816 struct fuse_inode *fi = get_fuse_inode(inode);
1817 struct fuse_conn *fc = get_fuse_conn(inode);
1818
1819 mapping_set_error(inode->i_mapping, error);
1820 /*
1821 * A writeback finished and this might have updated mtime/ctime on
1822 * server making local mtime/ctime stale. Hence invalidate attrs.
1823 * Do this only if writeback_cache is not enabled. If writeback_cache
1824 * is enabled, we trust local ctime/mtime.
1825 */
1826 if (!fc->writeback_cache)
1827 fuse_invalidate_attr_mask(inode, FUSE_STATX_MODIFY);
1828 spin_lock(&fi->lock);
1829 rb_erase(&wpa->writepages_entry, &fi->writepages);
1830 while (wpa->next) {
1831 struct fuse_mount *fm = get_fuse_mount(inode);
1832 struct fuse_write_in *inarg = &wpa->ia.write.in;
1833 struct fuse_writepage_args *next = wpa->next;
1834
1835 wpa->next = next->next;
1836 next->next = NULL;
1837 next->ia.ff = fuse_file_get(wpa->ia.ff);
1838 tree_insert(&fi->writepages, next);
1839
1840 /*
1841 * Skip fuse_flush_writepages() to make it easy to crop requests
1842 * based on primary request size.
1843 *
1844 * 1st case (trivial): there are no concurrent activities using
1845 * fuse_set/release_nowrite. Then we're on safe side because
1846 * fuse_flush_writepages() would call fuse_send_writepage()
1847 * anyway.
1848 *
1849 * 2nd case: someone called fuse_set_nowrite and it is waiting
1850 * now for completion of all in-flight requests. This happens
1851 * rarely and no more than once per page, so this should be
1852 * okay.
1853 *
1854 * 3rd case: someone (e.g. fuse_do_setattr()) is in the middle
1855 * of fuse_set_nowrite..fuse_release_nowrite section. The fact
1856 * that fuse_set_nowrite returned implies that all in-flight
1857 * requests were completed along with all of their secondary
1858 * requests. Further primary requests are blocked by negative
1859 * writectr. Hence there cannot be any in-flight requests and
1860 * no invocations of fuse_writepage_end() while we're in
1861 * fuse_set_nowrite..fuse_release_nowrite section.
1862 */
1863 fuse_send_writepage(fm, next, inarg->offset + inarg->size);
1864 }
1865 fi->writectr--;
1866 fuse_writepage_finish(fm, wpa);
1867 spin_unlock(&fi->lock);
1868 fuse_writepage_free(wpa);
1869 }
1870
__fuse_write_file_get(struct fuse_inode * fi)1871 static struct fuse_file *__fuse_write_file_get(struct fuse_inode *fi)
1872 {
1873 struct fuse_file *ff;
1874
1875 spin_lock(&fi->lock);
1876 ff = list_first_entry_or_null(&fi->write_files, struct fuse_file,
1877 write_entry);
1878 if (ff)
1879 fuse_file_get(ff);
1880 spin_unlock(&fi->lock);
1881
1882 return ff;
1883 }
1884
fuse_write_file_get(struct fuse_inode * fi)1885 static struct fuse_file *fuse_write_file_get(struct fuse_inode *fi)
1886 {
1887 struct fuse_file *ff = __fuse_write_file_get(fi);
1888 WARN_ON(!ff);
1889 return ff;
1890 }
1891
fuse_write_inode(struct inode * inode,struct writeback_control * wbc)1892 int fuse_write_inode(struct inode *inode, struct writeback_control *wbc)
1893 {
1894 struct fuse_inode *fi = get_fuse_inode(inode);
1895 struct fuse_file *ff;
1896 int err;
1897
1898 /*
1899 * Inode is always written before the last reference is dropped and
1900 * hence this should not be reached from reclaim.
1901 *
1902 * Writing back the inode from reclaim can deadlock if the request
1903 * processing itself needs an allocation. Allocations triggering
1904 * reclaim while serving a request can't be prevented, because it can
1905 * involve any number of unrelated userspace processes.
1906 */
1907 WARN_ON(wbc->for_reclaim);
1908
1909 ff = __fuse_write_file_get(fi);
1910 err = fuse_flush_times(inode, ff);
1911 if (ff)
1912 fuse_file_put(ff, false, false);
1913
1914 return err;
1915 }
1916
fuse_writepage_args_alloc(void)1917 static struct fuse_writepage_args *fuse_writepage_args_alloc(void)
1918 {
1919 struct fuse_writepage_args *wpa;
1920 struct fuse_args_pages *ap;
1921
1922 wpa = kzalloc(sizeof(*wpa), GFP_NOFS);
1923 if (wpa) {
1924 ap = &wpa->ia.ap;
1925 ap->num_pages = 0;
1926 ap->pages = fuse_pages_alloc(1, GFP_NOFS, &ap->descs);
1927 if (!ap->pages) {
1928 kfree(wpa);
1929 wpa = NULL;
1930 }
1931 }
1932 return wpa;
1933
1934 }
1935
fuse_writepage_add_to_bucket(struct fuse_conn * fc,struct fuse_writepage_args * wpa)1936 static void fuse_writepage_add_to_bucket(struct fuse_conn *fc,
1937 struct fuse_writepage_args *wpa)
1938 {
1939 if (!fc->sync_fs)
1940 return;
1941
1942 rcu_read_lock();
1943 /* Prevent resurrection of dead bucket in unlikely race with syncfs */
1944 do {
1945 wpa->bucket = rcu_dereference(fc->curr_bucket);
1946 } while (unlikely(!atomic_inc_not_zero(&wpa->bucket->count)));
1947 rcu_read_unlock();
1948 }
1949
fuse_writepage_locked(struct page * page)1950 static int fuse_writepage_locked(struct page *page)
1951 {
1952 struct address_space *mapping = page->mapping;
1953 struct inode *inode = mapping->host;
1954 struct fuse_conn *fc = get_fuse_conn(inode);
1955 struct fuse_inode *fi = get_fuse_inode(inode);
1956 struct fuse_writepage_args *wpa;
1957 struct fuse_args_pages *ap;
1958 struct page *tmp_page;
1959 int error = -ENOMEM;
1960
1961 set_page_writeback(page);
1962
1963 wpa = fuse_writepage_args_alloc();
1964 if (!wpa)
1965 goto err;
1966 ap = &wpa->ia.ap;
1967
1968 tmp_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
1969 if (!tmp_page)
1970 goto err_free;
1971
1972 error = -EIO;
1973 wpa->ia.ff = fuse_write_file_get(fi);
1974 if (!wpa->ia.ff)
1975 goto err_nofile;
1976
1977 fuse_writepage_add_to_bucket(fc, wpa);
1978 fuse_write_args_fill(&wpa->ia, wpa->ia.ff, page_offset(page), 0);
1979
1980 copy_highpage(tmp_page, page);
1981 wpa->ia.write.in.write_flags |= FUSE_WRITE_CACHE;
1982 wpa->next = NULL;
1983 ap->args.in_pages = true;
1984 ap->num_pages = 1;
1985 ap->pages[0] = tmp_page;
1986 ap->descs[0].offset = 0;
1987 ap->descs[0].length = PAGE_SIZE;
1988 ap->args.end = fuse_writepage_end;
1989 wpa->inode = inode;
1990
1991 inc_wb_stat(&inode_to_bdi(inode)->wb, WB_WRITEBACK);
1992 inc_node_page_state(tmp_page, NR_WRITEBACK_TEMP);
1993
1994 spin_lock(&fi->lock);
1995 tree_insert(&fi->writepages, wpa);
1996 list_add_tail(&wpa->queue_entry, &fi->queued_writes);
1997 fuse_flush_writepages(inode);
1998 spin_unlock(&fi->lock);
1999
2000 end_page_writeback(page);
2001
2002 return 0;
2003
2004 err_nofile:
2005 __free_page(tmp_page);
2006 err_free:
2007 kfree(wpa);
2008 err:
2009 mapping_set_error(page->mapping, error);
2010 end_page_writeback(page);
2011 return error;
2012 }
2013
fuse_writepage(struct page * page,struct writeback_control * wbc)2014 static int fuse_writepage(struct page *page, struct writeback_control *wbc)
2015 {
2016 struct fuse_conn *fc = get_fuse_conn(page->mapping->host);
2017 int err;
2018
2019 if (fuse_page_is_writeback(page->mapping->host, page->index)) {
2020 /*
2021 * ->writepages() should be called for sync() and friends. We
2022 * should only get here on direct reclaim and then we are
2023 * allowed to skip a page which is already in flight
2024 */
2025 WARN_ON(wbc->sync_mode == WB_SYNC_ALL);
2026
2027 redirty_page_for_writepage(wbc, page);
2028 unlock_page(page);
2029 return 0;
2030 }
2031
2032 if (wbc->sync_mode == WB_SYNC_NONE &&
2033 fc->num_background >= fc->congestion_threshold)
2034 return AOP_WRITEPAGE_ACTIVATE;
2035
2036 err = fuse_writepage_locked(page);
2037 unlock_page(page);
2038
2039 return err;
2040 }
2041
2042 struct fuse_fill_wb_data {
2043 struct fuse_writepage_args *wpa;
2044 struct fuse_file *ff;
2045 struct inode *inode;
2046 struct page **orig_pages;
2047 unsigned int max_pages;
2048 };
2049
fuse_pages_realloc(struct fuse_fill_wb_data * data)2050 static bool fuse_pages_realloc(struct fuse_fill_wb_data *data)
2051 {
2052 struct fuse_args_pages *ap = &data->wpa->ia.ap;
2053 struct fuse_conn *fc = get_fuse_conn(data->inode);
2054 struct page **pages;
2055 struct fuse_page_desc *descs;
2056 unsigned int npages = min_t(unsigned int,
2057 max_t(unsigned int, data->max_pages * 2,
2058 FUSE_DEFAULT_MAX_PAGES_PER_REQ),
2059 fc->max_pages);
2060 WARN_ON(npages <= data->max_pages);
2061
2062 pages = fuse_pages_alloc(npages, GFP_NOFS, &descs);
2063 if (!pages)
2064 return false;
2065
2066 memcpy(pages, ap->pages, sizeof(struct page *) * ap->num_pages);
2067 memcpy(descs, ap->descs, sizeof(struct fuse_page_desc) * ap->num_pages);
2068 kfree(ap->pages);
2069 ap->pages = pages;
2070 ap->descs = descs;
2071 data->max_pages = npages;
2072
2073 return true;
2074 }
2075
fuse_writepages_send(struct fuse_fill_wb_data * data)2076 static void fuse_writepages_send(struct fuse_fill_wb_data *data)
2077 {
2078 struct fuse_writepage_args *wpa = data->wpa;
2079 struct inode *inode = data->inode;
2080 struct fuse_inode *fi = get_fuse_inode(inode);
2081 int num_pages = wpa->ia.ap.num_pages;
2082 int i;
2083
2084 wpa->ia.ff = fuse_file_get(data->ff);
2085 spin_lock(&fi->lock);
2086 list_add_tail(&wpa->queue_entry, &fi->queued_writes);
2087 fuse_flush_writepages(inode);
2088 spin_unlock(&fi->lock);
2089
2090 for (i = 0; i < num_pages; i++)
2091 end_page_writeback(data->orig_pages[i]);
2092 }
2093
2094 /*
2095 * Check under fi->lock if the page is under writeback, and insert it onto the
2096 * rb_tree if not. Otherwise iterate auxiliary write requests, to see if there's
2097 * one already added for a page at this offset. If there's none, then insert
2098 * this new request onto the auxiliary list, otherwise reuse the existing one by
2099 * swapping the new temp page with the old one.
2100 */
fuse_writepage_add(struct fuse_writepage_args * new_wpa,struct page * page)2101 static bool fuse_writepage_add(struct fuse_writepage_args *new_wpa,
2102 struct page *page)
2103 {
2104 struct fuse_inode *fi = get_fuse_inode(new_wpa->inode);
2105 struct fuse_writepage_args *tmp;
2106 struct fuse_writepage_args *old_wpa;
2107 struct fuse_args_pages *new_ap = &new_wpa->ia.ap;
2108
2109 WARN_ON(new_ap->num_pages != 0);
2110 new_ap->num_pages = 1;
2111
2112 spin_lock(&fi->lock);
2113 old_wpa = fuse_insert_writeback(&fi->writepages, new_wpa);
2114 if (!old_wpa) {
2115 spin_unlock(&fi->lock);
2116 return true;
2117 }
2118
2119 for (tmp = old_wpa->next; tmp; tmp = tmp->next) {
2120 pgoff_t curr_index;
2121
2122 WARN_ON(tmp->inode != new_wpa->inode);
2123 curr_index = tmp->ia.write.in.offset >> PAGE_SHIFT;
2124 if (curr_index == page->index) {
2125 WARN_ON(tmp->ia.ap.num_pages != 1);
2126 swap(tmp->ia.ap.pages[0], new_ap->pages[0]);
2127 break;
2128 }
2129 }
2130
2131 if (!tmp) {
2132 new_wpa->next = old_wpa->next;
2133 old_wpa->next = new_wpa;
2134 }
2135
2136 spin_unlock(&fi->lock);
2137
2138 if (tmp) {
2139 struct backing_dev_info *bdi = inode_to_bdi(new_wpa->inode);
2140
2141 dec_wb_stat(&bdi->wb, WB_WRITEBACK);
2142 dec_node_page_state(new_ap->pages[0], NR_WRITEBACK_TEMP);
2143 wb_writeout_inc(&bdi->wb);
2144 fuse_writepage_free(new_wpa);
2145 }
2146
2147 return false;
2148 }
2149
fuse_writepage_need_send(struct fuse_conn * fc,struct page * page,struct fuse_args_pages * ap,struct fuse_fill_wb_data * data)2150 static bool fuse_writepage_need_send(struct fuse_conn *fc, struct page *page,
2151 struct fuse_args_pages *ap,
2152 struct fuse_fill_wb_data *data)
2153 {
2154 WARN_ON(!ap->num_pages);
2155
2156 /*
2157 * Being under writeback is unlikely but possible. For example direct
2158 * read to an mmaped fuse file will set the page dirty twice; once when
2159 * the pages are faulted with get_user_pages(), and then after the read
2160 * completed.
2161 */
2162 if (fuse_page_is_writeback(data->inode, page->index))
2163 return true;
2164
2165 /* Reached max pages */
2166 if (ap->num_pages == fc->max_pages)
2167 return true;
2168
2169 /* Reached max write bytes */
2170 if ((ap->num_pages + 1) * PAGE_SIZE > fc->max_write)
2171 return true;
2172
2173 /* Discontinuity */
2174 if (data->orig_pages[ap->num_pages - 1]->index + 1 != page->index)
2175 return true;
2176
2177 /* Need to grow the pages array? If so, did the expansion fail? */
2178 if (ap->num_pages == data->max_pages && !fuse_pages_realloc(data))
2179 return true;
2180
2181 return false;
2182 }
2183
fuse_writepages_fill(struct folio * folio,struct writeback_control * wbc,void * _data)2184 static int fuse_writepages_fill(struct folio *folio,
2185 struct writeback_control *wbc, void *_data)
2186 {
2187 struct fuse_fill_wb_data *data = _data;
2188 struct fuse_writepage_args *wpa = data->wpa;
2189 struct fuse_args_pages *ap = &wpa->ia.ap;
2190 struct inode *inode = data->inode;
2191 struct fuse_inode *fi = get_fuse_inode(inode);
2192 struct fuse_conn *fc = get_fuse_conn(inode);
2193 struct page *tmp_page;
2194 int err;
2195
2196 if (!data->ff) {
2197 err = -EIO;
2198 data->ff = fuse_write_file_get(fi);
2199 if (!data->ff)
2200 goto out_unlock;
2201 }
2202
2203 if (wpa && fuse_writepage_need_send(fc, &folio->page, ap, data)) {
2204 fuse_writepages_send(data);
2205 data->wpa = NULL;
2206 }
2207
2208 err = -ENOMEM;
2209 tmp_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
2210 if (!tmp_page)
2211 goto out_unlock;
2212
2213 /*
2214 * The page must not be redirtied until the writeout is completed
2215 * (i.e. userspace has sent a reply to the write request). Otherwise
2216 * there could be more than one temporary page instance for each real
2217 * page.
2218 *
2219 * This is ensured by holding the page lock in page_mkwrite() while
2220 * checking fuse_page_is_writeback(). We already hold the page lock
2221 * since clear_page_dirty_for_io() and keep it held until we add the
2222 * request to the fi->writepages list and increment ap->num_pages.
2223 * After this fuse_page_is_writeback() will indicate that the page is
2224 * under writeback, so we can release the page lock.
2225 */
2226 if (data->wpa == NULL) {
2227 err = -ENOMEM;
2228 wpa = fuse_writepage_args_alloc();
2229 if (!wpa) {
2230 __free_page(tmp_page);
2231 goto out_unlock;
2232 }
2233 fuse_writepage_add_to_bucket(fc, wpa);
2234
2235 data->max_pages = 1;
2236
2237 ap = &wpa->ia.ap;
2238 fuse_write_args_fill(&wpa->ia, data->ff, folio_pos(folio), 0);
2239 wpa->ia.write.in.write_flags |= FUSE_WRITE_CACHE;
2240 wpa->next = NULL;
2241 ap->args.in_pages = true;
2242 ap->args.end = fuse_writepage_end;
2243 ap->num_pages = 0;
2244 wpa->inode = inode;
2245 }
2246 folio_start_writeback(folio);
2247
2248 copy_highpage(tmp_page, &folio->page);
2249 ap->pages[ap->num_pages] = tmp_page;
2250 ap->descs[ap->num_pages].offset = 0;
2251 ap->descs[ap->num_pages].length = PAGE_SIZE;
2252 data->orig_pages[ap->num_pages] = &folio->page;
2253
2254 inc_wb_stat(&inode_to_bdi(inode)->wb, WB_WRITEBACK);
2255 inc_node_page_state(tmp_page, NR_WRITEBACK_TEMP);
2256
2257 err = 0;
2258 if (data->wpa) {
2259 /*
2260 * Protected by fi->lock against concurrent access by
2261 * fuse_page_is_writeback().
2262 */
2263 spin_lock(&fi->lock);
2264 ap->num_pages++;
2265 spin_unlock(&fi->lock);
2266 } else if (fuse_writepage_add(wpa, &folio->page)) {
2267 data->wpa = wpa;
2268 } else {
2269 folio_end_writeback(folio);
2270 }
2271 out_unlock:
2272 folio_unlock(folio);
2273
2274 return err;
2275 }
2276
fuse_writepages(struct address_space * mapping,struct writeback_control * wbc)2277 static int fuse_writepages(struct address_space *mapping,
2278 struct writeback_control *wbc)
2279 {
2280 struct inode *inode = mapping->host;
2281 struct fuse_conn *fc = get_fuse_conn(inode);
2282 struct fuse_fill_wb_data data;
2283 int err;
2284
2285 err = -EIO;
2286 if (fuse_is_bad(inode))
2287 goto out;
2288
2289 if (wbc->sync_mode == WB_SYNC_NONE &&
2290 fc->num_background >= fc->congestion_threshold)
2291 return 0;
2292
2293 data.inode = inode;
2294 data.wpa = NULL;
2295 data.ff = NULL;
2296
2297 err = -ENOMEM;
2298 data.orig_pages = kcalloc(fc->max_pages,
2299 sizeof(struct page *),
2300 GFP_NOFS);
2301 if (!data.orig_pages)
2302 goto out;
2303
2304 err = write_cache_pages(mapping, wbc, fuse_writepages_fill, &data);
2305 if (data.wpa) {
2306 WARN_ON(!data.wpa->ia.ap.num_pages);
2307 fuse_writepages_send(&data);
2308 }
2309 if (data.ff)
2310 fuse_file_put(data.ff, false, false);
2311
2312 kfree(data.orig_pages);
2313 out:
2314 return err;
2315 }
2316
2317 /*
2318 * It's worthy to make sure that space is reserved on disk for the write,
2319 * but how to implement it without killing performance need more thinking.
2320 */
fuse_write_begin(struct file * file,struct address_space * mapping,loff_t pos,unsigned len,struct page ** pagep,void ** fsdata)2321 static int fuse_write_begin(struct file *file, struct address_space *mapping,
2322 loff_t pos, unsigned len, struct page **pagep, void **fsdata)
2323 {
2324 pgoff_t index = pos >> PAGE_SHIFT;
2325 struct fuse_conn *fc = get_fuse_conn(file_inode(file));
2326 struct page *page;
2327 loff_t fsize;
2328 int err = -ENOMEM;
2329
2330 WARN_ON(!fc->writeback_cache);
2331
2332 page = grab_cache_page_write_begin(mapping, index);
2333 if (!page)
2334 goto error;
2335
2336 fuse_wait_on_page_writeback(mapping->host, page->index);
2337
2338 if (PageUptodate(page) || len == PAGE_SIZE)
2339 goto success;
2340 /*
2341 * Check if the start this page comes after the end of file, in which
2342 * case the readpage can be optimized away.
2343 */
2344 fsize = i_size_read(mapping->host);
2345 if (fsize <= (pos & PAGE_MASK)) {
2346 size_t off = pos & ~PAGE_MASK;
2347 if (off)
2348 zero_user_segment(page, 0, off);
2349 goto success;
2350 }
2351 err = fuse_do_readpage(file, page);
2352 if (err)
2353 goto cleanup;
2354 success:
2355 *pagep = page;
2356 return 0;
2357
2358 cleanup:
2359 unlock_page(page);
2360 put_page(page);
2361 error:
2362 return err;
2363 }
2364
fuse_write_end(struct file * file,struct address_space * mapping,loff_t pos,unsigned len,unsigned copied,struct page * page,void * fsdata)2365 static int fuse_write_end(struct file *file, struct address_space *mapping,
2366 loff_t pos, unsigned len, unsigned copied,
2367 struct page *page, void *fsdata)
2368 {
2369 struct inode *inode = page->mapping->host;
2370
2371 /* Haven't copied anything? Skip zeroing, size extending, dirtying. */
2372 if (!copied)
2373 goto unlock;
2374
2375 pos += copied;
2376 if (!PageUptodate(page)) {
2377 /* Zero any unwritten bytes at the end of the page */
2378 size_t endoff = pos & ~PAGE_MASK;
2379 if (endoff)
2380 zero_user_segment(page, endoff, PAGE_SIZE);
2381 SetPageUptodate(page);
2382 }
2383
2384 if (pos > inode->i_size)
2385 i_size_write(inode, pos);
2386
2387 set_page_dirty(page);
2388
2389 unlock:
2390 unlock_page(page);
2391 put_page(page);
2392
2393 return copied;
2394 }
2395
fuse_launder_folio(struct folio * folio)2396 static int fuse_launder_folio(struct folio *folio)
2397 {
2398 int err = 0;
2399 if (folio_clear_dirty_for_io(folio)) {
2400 struct inode *inode = folio->mapping->host;
2401
2402 /* Serialize with pending writeback for the same page */
2403 fuse_wait_on_page_writeback(inode, folio->index);
2404 err = fuse_writepage_locked(&folio->page);
2405 if (!err)
2406 fuse_wait_on_page_writeback(inode, folio->index);
2407 }
2408 return err;
2409 }
2410
2411 /*
2412 * Write back dirty data/metadata now (there may not be any suitable
2413 * open files later for data)
2414 */
fuse_vma_close(struct vm_area_struct * vma)2415 static void fuse_vma_close(struct vm_area_struct *vma)
2416 {
2417 int err;
2418
2419 err = write_inode_now(vma->vm_file->f_mapping->host, 1);
2420 mapping_set_error(vma->vm_file->f_mapping, err);
2421 }
2422
2423 /*
2424 * Wait for writeback against this page to complete before allowing it
2425 * to be marked dirty again, and hence written back again, possibly
2426 * before the previous writepage completed.
2427 *
2428 * Block here, instead of in ->writepage(), so that the userspace fs
2429 * can only block processes actually operating on the filesystem.
2430 *
2431 * Otherwise unprivileged userspace fs would be able to block
2432 * unrelated:
2433 *
2434 * - page migration
2435 * - sync(2)
2436 * - try_to_free_pages() with order > PAGE_ALLOC_COSTLY_ORDER
2437 */
fuse_page_mkwrite(struct vm_fault * vmf)2438 static vm_fault_t fuse_page_mkwrite(struct vm_fault *vmf)
2439 {
2440 struct page *page = vmf->page;
2441 struct inode *inode = file_inode(vmf->vma->vm_file);
2442
2443 file_update_time(vmf->vma->vm_file);
2444 lock_page(page);
2445 if (page->mapping != inode->i_mapping) {
2446 unlock_page(page);
2447 return VM_FAULT_NOPAGE;
2448 }
2449
2450 fuse_wait_on_page_writeback(inode, page->index);
2451 return VM_FAULT_LOCKED;
2452 }
2453
2454 static const struct vm_operations_struct fuse_file_vm_ops = {
2455 .close = fuse_vma_close,
2456 .fault = filemap_fault,
2457 .map_pages = filemap_map_pages,
2458 .page_mkwrite = fuse_page_mkwrite,
2459 };
2460
fuse_file_mmap(struct file * file,struct vm_area_struct * vma)2461 static int fuse_file_mmap(struct file *file, struct vm_area_struct *vma)
2462 {
2463 struct fuse_file *ff = file->private_data;
2464 struct fuse_conn *fc = ff->fm->fc;
2465
2466 /* DAX mmap is superior to direct_io mmap */
2467 if (FUSE_IS_DAX(file_inode(file)))
2468 return fuse_dax_mmap(file, vma);
2469
2470 if (ff->open_flags & FOPEN_DIRECT_IO) {
2471 /* Can't provide the coherency needed for MAP_SHARED
2472 * if FUSE_DIRECT_IO_ALLOW_MMAP isn't set.
2473 */
2474 if ((vma->vm_flags & VM_MAYSHARE) && !fc->direct_io_allow_mmap)
2475 return -ENODEV;
2476
2477 invalidate_inode_pages2(file->f_mapping);
2478
2479 return generic_file_mmap(file, vma);
2480 }
2481
2482 if ((vma->vm_flags & VM_SHARED) && (vma->vm_flags & VM_MAYWRITE))
2483 fuse_link_write_file(file);
2484
2485 file_accessed(file);
2486 vma->vm_ops = &fuse_file_vm_ops;
2487 return 0;
2488 }
2489
convert_fuse_file_lock(struct fuse_conn * fc,const struct fuse_file_lock * ffl,struct file_lock * fl)2490 static int convert_fuse_file_lock(struct fuse_conn *fc,
2491 const struct fuse_file_lock *ffl,
2492 struct file_lock *fl)
2493 {
2494 switch (ffl->type) {
2495 case F_UNLCK:
2496 break;
2497
2498 case F_RDLCK:
2499 case F_WRLCK:
2500 if (ffl->start > OFFSET_MAX || ffl->end > OFFSET_MAX ||
2501 ffl->end < ffl->start)
2502 return -EIO;
2503
2504 fl->fl_start = ffl->start;
2505 fl->fl_end = ffl->end;
2506
2507 /*
2508 * Convert pid into init's pid namespace. The locks API will
2509 * translate it into the caller's pid namespace.
2510 */
2511 rcu_read_lock();
2512 fl->fl_pid = pid_nr_ns(find_pid_ns(ffl->pid, fc->pid_ns), &init_pid_ns);
2513 rcu_read_unlock();
2514 break;
2515
2516 default:
2517 return -EIO;
2518 }
2519 fl->fl_type = ffl->type;
2520 return 0;
2521 }
2522
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)2523 static void fuse_lk_fill(struct fuse_args *args, struct file *file,
2524 const struct file_lock *fl, int opcode, pid_t pid,
2525 int flock, struct fuse_lk_in *inarg)
2526 {
2527 struct inode *inode = file_inode(file);
2528 struct fuse_conn *fc = get_fuse_conn(inode);
2529 struct fuse_file *ff = file->private_data;
2530
2531 memset(inarg, 0, sizeof(*inarg));
2532 inarg->fh = ff->fh;
2533 inarg->owner = fuse_lock_owner_id(fc, fl->fl_owner);
2534 inarg->lk.start = fl->fl_start;
2535 inarg->lk.end = fl->fl_end;
2536 inarg->lk.type = fl->fl_type;
2537 inarg->lk.pid = pid;
2538 if (flock)
2539 inarg->lk_flags |= FUSE_LK_FLOCK;
2540 args->opcode = opcode;
2541 args->nodeid = get_node_id(inode);
2542 args->in_numargs = 1;
2543 args->in_args[0].size = sizeof(*inarg);
2544 args->in_args[0].value = inarg;
2545 }
2546
fuse_getlk(struct file * file,struct file_lock * fl)2547 static int fuse_getlk(struct file *file, struct file_lock *fl)
2548 {
2549 struct inode *inode = file_inode(file);
2550 struct fuse_mount *fm = get_fuse_mount(inode);
2551 FUSE_ARGS(args);
2552 struct fuse_lk_in inarg;
2553 struct fuse_lk_out outarg;
2554 int err;
2555
2556 fuse_lk_fill(&args, file, fl, FUSE_GETLK, 0, 0, &inarg);
2557 args.out_numargs = 1;
2558 args.out_args[0].size = sizeof(outarg);
2559 args.out_args[0].value = &outarg;
2560 err = fuse_simple_request(fm, &args);
2561 if (!err)
2562 err = convert_fuse_file_lock(fm->fc, &outarg.lk, fl);
2563
2564 return err;
2565 }
2566
fuse_setlk(struct file * file,struct file_lock * fl,int flock)2567 static int fuse_setlk(struct file *file, struct file_lock *fl, int flock)
2568 {
2569 struct inode *inode = file_inode(file);
2570 struct fuse_mount *fm = get_fuse_mount(inode);
2571 FUSE_ARGS(args);
2572 struct fuse_lk_in inarg;
2573 int opcode = (fl->fl_flags & FL_SLEEP) ? FUSE_SETLKW : FUSE_SETLK;
2574 struct pid *pid = fl->fl_type != F_UNLCK ? task_tgid(current) : NULL;
2575 pid_t pid_nr = pid_nr_ns(pid, fm->fc->pid_ns);
2576 int err;
2577
2578 if (fl->fl_lmops && fl->fl_lmops->lm_grant) {
2579 /* NLM needs asynchronous locks, which we don't support yet */
2580 return -ENOLCK;
2581 }
2582
2583 /* Unlock on close is handled by the flush method */
2584 if ((fl->fl_flags & FL_CLOSE_POSIX) == FL_CLOSE_POSIX)
2585 return 0;
2586
2587 fuse_lk_fill(&args, file, fl, opcode, pid_nr, flock, &inarg);
2588 err = fuse_simple_request(fm, &args);
2589
2590 /* locking is restartable */
2591 if (err == -EINTR)
2592 err = -ERESTARTSYS;
2593
2594 return err;
2595 }
2596
fuse_file_lock(struct file * file,int cmd,struct file_lock * fl)2597 static int fuse_file_lock(struct file *file, int cmd, struct file_lock *fl)
2598 {
2599 struct inode *inode = file_inode(file);
2600 struct fuse_conn *fc = get_fuse_conn(inode);
2601 int err;
2602
2603 if (cmd == F_CANCELLK) {
2604 err = 0;
2605 } else if (cmd == F_GETLK) {
2606 if (fc->no_lock) {
2607 posix_test_lock(file, fl);
2608 err = 0;
2609 } else
2610 err = fuse_getlk(file, fl);
2611 } else {
2612 if (fc->no_lock)
2613 err = posix_lock_file(file, fl, NULL);
2614 else
2615 err = fuse_setlk(file, fl, 0);
2616 }
2617 return err;
2618 }
2619
fuse_file_flock(struct file * file,int cmd,struct file_lock * fl)2620 static int fuse_file_flock(struct file *file, int cmd, struct file_lock *fl)
2621 {
2622 struct inode *inode = file_inode(file);
2623 struct fuse_conn *fc = get_fuse_conn(inode);
2624 int err;
2625
2626 if (fc->no_flock) {
2627 err = locks_lock_file_wait(file, fl);
2628 } else {
2629 struct fuse_file *ff = file->private_data;
2630
2631 /* emulate flock with POSIX locks */
2632 ff->flock = true;
2633 err = fuse_setlk(file, fl, 1);
2634 }
2635
2636 return err;
2637 }
2638
fuse_bmap(struct address_space * mapping,sector_t block)2639 static sector_t fuse_bmap(struct address_space *mapping, sector_t block)
2640 {
2641 struct inode *inode = mapping->host;
2642 struct fuse_mount *fm = get_fuse_mount(inode);
2643 FUSE_ARGS(args);
2644 struct fuse_bmap_in inarg;
2645 struct fuse_bmap_out outarg;
2646 int err;
2647
2648 if (!inode->i_sb->s_bdev || fm->fc->no_bmap)
2649 return 0;
2650
2651 memset(&inarg, 0, sizeof(inarg));
2652 inarg.block = block;
2653 inarg.blocksize = inode->i_sb->s_blocksize;
2654 args.opcode = FUSE_BMAP;
2655 args.nodeid = get_node_id(inode);
2656 args.in_numargs = 1;
2657 args.in_args[0].size = sizeof(inarg);
2658 args.in_args[0].value = &inarg;
2659 args.out_numargs = 1;
2660 args.out_args[0].size = sizeof(outarg);
2661 args.out_args[0].value = &outarg;
2662 err = fuse_simple_request(fm, &args);
2663 if (err == -ENOSYS)
2664 fm->fc->no_bmap = 1;
2665
2666 return err ? 0 : outarg.block;
2667 }
2668
fuse_lseek(struct file * file,loff_t offset,int whence)2669 static loff_t fuse_lseek(struct file *file, loff_t offset, int whence)
2670 {
2671 struct inode *inode = file->f_mapping->host;
2672 struct fuse_mount *fm = get_fuse_mount(inode);
2673 struct fuse_file *ff = file->private_data;
2674 FUSE_ARGS(args);
2675 struct fuse_lseek_in inarg = {
2676 .fh = ff->fh,
2677 .offset = offset,
2678 .whence = whence
2679 };
2680 struct fuse_lseek_out outarg;
2681 int err;
2682
2683 if (fm->fc->no_lseek)
2684 goto fallback;
2685
2686 args.opcode = FUSE_LSEEK;
2687 args.nodeid = ff->nodeid;
2688 args.in_numargs = 1;
2689 args.in_args[0].size = sizeof(inarg);
2690 args.in_args[0].value = &inarg;
2691 args.out_numargs = 1;
2692 args.out_args[0].size = sizeof(outarg);
2693 args.out_args[0].value = &outarg;
2694 err = fuse_simple_request(fm, &args);
2695 if (err) {
2696 if (err == -ENOSYS) {
2697 fm->fc->no_lseek = 1;
2698 goto fallback;
2699 }
2700 return err;
2701 }
2702
2703 return vfs_setpos(file, outarg.offset, inode->i_sb->s_maxbytes);
2704
2705 fallback:
2706 err = fuse_update_attributes(inode, file, STATX_SIZE);
2707 if (!err)
2708 return generic_file_llseek(file, offset, whence);
2709 else
2710 return err;
2711 }
2712
fuse_file_llseek(struct file * file,loff_t offset,int whence)2713 static loff_t fuse_file_llseek(struct file *file, loff_t offset, int whence)
2714 {
2715 loff_t retval;
2716 struct inode *inode = file_inode(file);
2717
2718 switch (whence) {
2719 case SEEK_SET:
2720 case SEEK_CUR:
2721 /* No i_mutex protection necessary for SEEK_CUR and SEEK_SET */
2722 retval = generic_file_llseek(file, offset, whence);
2723 break;
2724 case SEEK_END:
2725 inode_lock(inode);
2726 retval = fuse_update_attributes(inode, file, STATX_SIZE);
2727 if (!retval)
2728 retval = generic_file_llseek(file, offset, whence);
2729 inode_unlock(inode);
2730 break;
2731 case SEEK_HOLE:
2732 case SEEK_DATA:
2733 inode_lock(inode);
2734 retval = fuse_lseek(file, offset, whence);
2735 inode_unlock(inode);
2736 break;
2737 default:
2738 retval = -EINVAL;
2739 }
2740
2741 return retval;
2742 }
2743
2744 /*
2745 * All files which have been polled are linked to RB tree
2746 * fuse_conn->polled_files which is indexed by kh. Walk the tree and
2747 * find the matching one.
2748 */
fuse_find_polled_node(struct fuse_conn * fc,u64 kh,struct rb_node ** parent_out)2749 static struct rb_node **fuse_find_polled_node(struct fuse_conn *fc, u64 kh,
2750 struct rb_node **parent_out)
2751 {
2752 struct rb_node **link = &fc->polled_files.rb_node;
2753 struct rb_node *last = NULL;
2754
2755 while (*link) {
2756 struct fuse_file *ff;
2757
2758 last = *link;
2759 ff = rb_entry(last, struct fuse_file, polled_node);
2760
2761 if (kh < ff->kh)
2762 link = &last->rb_left;
2763 else if (kh > ff->kh)
2764 link = &last->rb_right;
2765 else
2766 return link;
2767 }
2768
2769 if (parent_out)
2770 *parent_out = last;
2771 return link;
2772 }
2773
2774 /*
2775 * The file is about to be polled. Make sure it's on the polled_files
2776 * RB tree. Note that files once added to the polled_files tree are
2777 * not removed before the file is released. This is because a file
2778 * polled once is likely to be polled again.
2779 */
fuse_register_polled_file(struct fuse_conn * fc,struct fuse_file * ff)2780 static void fuse_register_polled_file(struct fuse_conn *fc,
2781 struct fuse_file *ff)
2782 {
2783 spin_lock(&fc->lock);
2784 if (RB_EMPTY_NODE(&ff->polled_node)) {
2785 struct rb_node **link, *parent;
2786
2787 link = fuse_find_polled_node(fc, ff->kh, &parent);
2788 BUG_ON(*link);
2789 rb_link_node(&ff->polled_node, parent, link);
2790 rb_insert_color(&ff->polled_node, &fc->polled_files);
2791 }
2792 spin_unlock(&fc->lock);
2793 }
2794
fuse_file_poll(struct file * file,poll_table * wait)2795 __poll_t fuse_file_poll(struct file *file, poll_table *wait)
2796 {
2797 struct fuse_file *ff = file->private_data;
2798 struct fuse_mount *fm = ff->fm;
2799 struct fuse_poll_in inarg = { .fh = ff->fh, .kh = ff->kh };
2800 struct fuse_poll_out outarg;
2801 FUSE_ARGS(args);
2802 int err;
2803
2804 if (fm->fc->no_poll)
2805 return DEFAULT_POLLMASK;
2806
2807 poll_wait(file, &ff->poll_wait, wait);
2808 inarg.events = mangle_poll(poll_requested_events(wait));
2809
2810 /*
2811 * Ask for notification iff there's someone waiting for it.
2812 * The client may ignore the flag and always notify.
2813 */
2814 if (waitqueue_active(&ff->poll_wait)) {
2815 inarg.flags |= FUSE_POLL_SCHEDULE_NOTIFY;
2816 fuse_register_polled_file(fm->fc, ff);
2817 }
2818
2819 args.opcode = FUSE_POLL;
2820 args.nodeid = ff->nodeid;
2821 args.in_numargs = 1;
2822 args.in_args[0].size = sizeof(inarg);
2823 args.in_args[0].value = &inarg;
2824 args.out_numargs = 1;
2825 args.out_args[0].size = sizeof(outarg);
2826 args.out_args[0].value = &outarg;
2827 err = fuse_simple_request(fm, &args);
2828
2829 if (!err)
2830 return demangle_poll(outarg.revents);
2831 if (err == -ENOSYS) {
2832 fm->fc->no_poll = 1;
2833 return DEFAULT_POLLMASK;
2834 }
2835 return EPOLLERR;
2836 }
2837 EXPORT_SYMBOL_GPL(fuse_file_poll);
2838
2839 /*
2840 * This is called from fuse_handle_notify() on FUSE_NOTIFY_POLL and
2841 * wakes up the poll waiters.
2842 */
fuse_notify_poll_wakeup(struct fuse_conn * fc,struct fuse_notify_poll_wakeup_out * outarg)2843 int fuse_notify_poll_wakeup(struct fuse_conn *fc,
2844 struct fuse_notify_poll_wakeup_out *outarg)
2845 {
2846 u64 kh = outarg->kh;
2847 struct rb_node **link;
2848
2849 spin_lock(&fc->lock);
2850
2851 link = fuse_find_polled_node(fc, kh, NULL);
2852 if (*link) {
2853 struct fuse_file *ff;
2854
2855 ff = rb_entry(*link, struct fuse_file, polled_node);
2856 wake_up_interruptible_sync(&ff->poll_wait);
2857 }
2858
2859 spin_unlock(&fc->lock);
2860 return 0;
2861 }
2862
fuse_do_truncate(struct file * file)2863 static void fuse_do_truncate(struct file *file)
2864 {
2865 struct inode *inode = file->f_mapping->host;
2866 struct iattr attr;
2867
2868 attr.ia_valid = ATTR_SIZE;
2869 attr.ia_size = i_size_read(inode);
2870
2871 attr.ia_file = file;
2872 attr.ia_valid |= ATTR_FILE;
2873
2874 fuse_do_setattr(file_dentry(file), &attr, file);
2875 }
2876
fuse_round_up(struct fuse_conn * fc,loff_t off)2877 static inline loff_t fuse_round_up(struct fuse_conn *fc, loff_t off)
2878 {
2879 return round_up(off, fc->max_pages << PAGE_SHIFT);
2880 }
2881
2882 static ssize_t
fuse_direct_IO(struct kiocb * iocb,struct iov_iter * iter)2883 fuse_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
2884 {
2885 DECLARE_COMPLETION_ONSTACK(wait);
2886 ssize_t ret = 0;
2887 struct file *file = iocb->ki_filp;
2888 struct fuse_file *ff = file->private_data;
2889 loff_t pos = 0;
2890 struct inode *inode;
2891 loff_t i_size;
2892 size_t count = iov_iter_count(iter), shortened = 0;
2893 loff_t offset = iocb->ki_pos;
2894 struct fuse_io_priv *io;
2895
2896 pos = offset;
2897 inode = file->f_mapping->host;
2898 i_size = i_size_read(inode);
2899
2900 if ((iov_iter_rw(iter) == READ) && (offset >= i_size))
2901 return 0;
2902
2903 io = kmalloc(sizeof(struct fuse_io_priv), GFP_KERNEL);
2904 if (!io)
2905 return -ENOMEM;
2906 spin_lock_init(&io->lock);
2907 kref_init(&io->refcnt);
2908 io->reqs = 1;
2909 io->bytes = -1;
2910 io->size = 0;
2911 io->offset = offset;
2912 io->write = (iov_iter_rw(iter) == WRITE);
2913 io->err = 0;
2914 /*
2915 * By default, we want to optimize all I/Os with async request
2916 * submission to the client filesystem if supported.
2917 */
2918 io->async = ff->fm->fc->async_dio;
2919 io->iocb = iocb;
2920 io->blocking = is_sync_kiocb(iocb);
2921
2922 /* optimization for short read */
2923 if (io->async && !io->write && offset + count > i_size) {
2924 iov_iter_truncate(iter, fuse_round_up(ff->fm->fc, i_size - offset));
2925 shortened = count - iov_iter_count(iter);
2926 count -= shortened;
2927 }
2928
2929 /*
2930 * We cannot asynchronously extend the size of a file.
2931 * In such case the aio will behave exactly like sync io.
2932 */
2933 if ((offset + count > i_size) && io->write)
2934 io->blocking = true;
2935
2936 if (io->async && io->blocking) {
2937 /*
2938 * Additional reference to keep io around after
2939 * calling fuse_aio_complete()
2940 */
2941 kref_get(&io->refcnt);
2942 io->done = &wait;
2943 }
2944
2945 if (iov_iter_rw(iter) == WRITE) {
2946 ret = fuse_direct_io(io, iter, &pos, FUSE_DIO_WRITE);
2947 fuse_invalidate_attr_mask(inode, FUSE_STATX_MODSIZE);
2948 } else {
2949 ret = __fuse_direct_read(io, iter, &pos);
2950 }
2951 iov_iter_reexpand(iter, iov_iter_count(iter) + shortened);
2952
2953 if (io->async) {
2954 bool blocking = io->blocking;
2955
2956 fuse_aio_complete(io, ret < 0 ? ret : 0, -1);
2957
2958 /* we have a non-extending, async request, so return */
2959 if (!blocking)
2960 return -EIOCBQUEUED;
2961
2962 wait_for_completion(&wait);
2963 ret = fuse_get_res_by_io(io);
2964 }
2965
2966 kref_put(&io->refcnt, fuse_io_release);
2967
2968 if (iov_iter_rw(iter) == WRITE) {
2969 fuse_write_update_attr(inode, pos, ret);
2970 /* For extending writes we already hold exclusive lock */
2971 if (ret < 0 && offset + count > i_size)
2972 fuse_do_truncate(file);
2973 }
2974
2975 return ret;
2976 }
2977
fuse_writeback_range(struct inode * inode,loff_t start,loff_t end)2978 static int fuse_writeback_range(struct inode *inode, loff_t start, loff_t end)
2979 {
2980 int err = filemap_write_and_wait_range(inode->i_mapping, start, LLONG_MAX);
2981
2982 if (!err)
2983 fuse_sync_writes(inode);
2984
2985 return err;
2986 }
2987
fuse_file_fallocate(struct file * file,int mode,loff_t offset,loff_t length)2988 static long fuse_file_fallocate(struct file *file, int mode, loff_t offset,
2989 loff_t length)
2990 {
2991 struct fuse_file *ff = file->private_data;
2992 struct inode *inode = file_inode(file);
2993 struct fuse_inode *fi = get_fuse_inode(inode);
2994 struct fuse_mount *fm = ff->fm;
2995 FUSE_ARGS(args);
2996 struct fuse_fallocate_in inarg = {
2997 .fh = ff->fh,
2998 .offset = offset,
2999 .length = length,
3000 .mode = mode
3001 };
3002 int err;
3003 bool block_faults = FUSE_IS_DAX(inode) &&
3004 (!(mode & FALLOC_FL_KEEP_SIZE) ||
3005 (mode & (FALLOC_FL_PUNCH_HOLE | FALLOC_FL_ZERO_RANGE)));
3006
3007 if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE |
3008 FALLOC_FL_ZERO_RANGE))
3009 return -EOPNOTSUPP;
3010
3011 if (fm->fc->no_fallocate)
3012 return -EOPNOTSUPP;
3013
3014 inode_lock(inode);
3015 if (block_faults) {
3016 filemap_invalidate_lock(inode->i_mapping);
3017 err = fuse_dax_break_layouts(inode, 0, 0);
3018 if (err)
3019 goto out;
3020 }
3021
3022 if (mode & (FALLOC_FL_PUNCH_HOLE | FALLOC_FL_ZERO_RANGE)) {
3023 loff_t endbyte = offset + length - 1;
3024
3025 err = fuse_writeback_range(inode, offset, endbyte);
3026 if (err)
3027 goto out;
3028 }
3029
3030 if (!(mode & FALLOC_FL_KEEP_SIZE) &&
3031 offset + length > i_size_read(inode)) {
3032 err = inode_newsize_ok(inode, offset + length);
3033 if (err)
3034 goto out;
3035 }
3036
3037 err = file_modified(file);
3038 if (err)
3039 goto out;
3040
3041 if (!(mode & FALLOC_FL_KEEP_SIZE))
3042 set_bit(FUSE_I_SIZE_UNSTABLE, &fi->state);
3043
3044 args.opcode = FUSE_FALLOCATE;
3045 args.nodeid = ff->nodeid;
3046 args.in_numargs = 1;
3047 args.in_args[0].size = sizeof(inarg);
3048 args.in_args[0].value = &inarg;
3049 err = fuse_simple_request(fm, &args);
3050 if (err == -ENOSYS) {
3051 fm->fc->no_fallocate = 1;
3052 err = -EOPNOTSUPP;
3053 }
3054 if (err)
3055 goto out;
3056
3057 /* we could have extended the file */
3058 if (!(mode & FALLOC_FL_KEEP_SIZE)) {
3059 if (fuse_write_update_attr(inode, offset + length, length))
3060 file_update_time(file);
3061 }
3062
3063 if (mode & (FALLOC_FL_PUNCH_HOLE | FALLOC_FL_ZERO_RANGE))
3064 truncate_pagecache_range(inode, offset, offset + length - 1);
3065
3066 fuse_invalidate_attr_mask(inode, FUSE_STATX_MODSIZE);
3067
3068 out:
3069 if (!(mode & FALLOC_FL_KEEP_SIZE))
3070 clear_bit(FUSE_I_SIZE_UNSTABLE, &fi->state);
3071
3072 if (block_faults)
3073 filemap_invalidate_unlock(inode->i_mapping);
3074
3075 inode_unlock(inode);
3076
3077 fuse_flush_time_update(inode);
3078
3079 return err;
3080 }
3081
__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)3082 static ssize_t __fuse_copy_file_range(struct file *file_in, loff_t pos_in,
3083 struct file *file_out, loff_t pos_out,
3084 size_t len, unsigned int flags)
3085 {
3086 struct fuse_file *ff_in = file_in->private_data;
3087 struct fuse_file *ff_out = file_out->private_data;
3088 struct inode *inode_in = file_inode(file_in);
3089 struct inode *inode_out = file_inode(file_out);
3090 struct fuse_inode *fi_out = get_fuse_inode(inode_out);
3091 struct fuse_mount *fm = ff_in->fm;
3092 struct fuse_conn *fc = fm->fc;
3093 FUSE_ARGS(args);
3094 struct fuse_copy_file_range_in inarg = {
3095 .fh_in = ff_in->fh,
3096 .off_in = pos_in,
3097 .nodeid_out = ff_out->nodeid,
3098 .fh_out = ff_out->fh,
3099 .off_out = pos_out,
3100 .len = len,
3101 .flags = flags
3102 };
3103 struct fuse_write_out outarg;
3104 ssize_t err;
3105 /* mark unstable when write-back is not used, and file_out gets
3106 * extended */
3107 bool is_unstable = (!fc->writeback_cache) &&
3108 ((pos_out + len) > inode_out->i_size);
3109
3110 if (fc->no_copy_file_range)
3111 return -EOPNOTSUPP;
3112
3113 if (file_inode(file_in)->i_sb != file_inode(file_out)->i_sb)
3114 return -EXDEV;
3115
3116 inode_lock(inode_in);
3117 err = fuse_writeback_range(inode_in, pos_in, pos_in + len - 1);
3118 inode_unlock(inode_in);
3119 if (err)
3120 return err;
3121
3122 inode_lock(inode_out);
3123
3124 err = file_modified(file_out);
3125 if (err)
3126 goto out;
3127
3128 /*
3129 * Write out dirty pages in the destination file before sending the COPY
3130 * request to userspace. After the request is completed, truncate off
3131 * pages (including partial ones) from the cache that have been copied,
3132 * since these contain stale data at that point.
3133 *
3134 * This should be mostly correct, but if the COPY writes to partial
3135 * pages (at the start or end) and the parts not covered by the COPY are
3136 * written through a memory map after calling fuse_writeback_range(),
3137 * then these partial page modifications will be lost on truncation.
3138 *
3139 * It is unlikely that someone would rely on such mixed style
3140 * modifications. Yet this does give less guarantees than if the
3141 * copying was performed with write(2).
3142 *
3143 * To fix this a mapping->invalidate_lock could be used to prevent new
3144 * faults while the copy is ongoing.
3145 */
3146 err = fuse_writeback_range(inode_out, pos_out, pos_out + len - 1);
3147 if (err)
3148 goto out;
3149
3150 if (is_unstable)
3151 set_bit(FUSE_I_SIZE_UNSTABLE, &fi_out->state);
3152
3153 args.opcode = FUSE_COPY_FILE_RANGE;
3154 args.nodeid = ff_in->nodeid;
3155 args.in_numargs = 1;
3156 args.in_args[0].size = sizeof(inarg);
3157 args.in_args[0].value = &inarg;
3158 args.out_numargs = 1;
3159 args.out_args[0].size = sizeof(outarg);
3160 args.out_args[0].value = &outarg;
3161 err = fuse_simple_request(fm, &args);
3162 if (err == -ENOSYS) {
3163 fc->no_copy_file_range = 1;
3164 err = -EOPNOTSUPP;
3165 }
3166 if (err)
3167 goto out;
3168
3169 truncate_inode_pages_range(inode_out->i_mapping,
3170 ALIGN_DOWN(pos_out, PAGE_SIZE),
3171 ALIGN(pos_out + outarg.size, PAGE_SIZE) - 1);
3172
3173 file_update_time(file_out);
3174 fuse_write_update_attr(inode_out, pos_out + outarg.size, outarg.size);
3175
3176 err = outarg.size;
3177 out:
3178 if (is_unstable)
3179 clear_bit(FUSE_I_SIZE_UNSTABLE, &fi_out->state);
3180
3181 inode_unlock(inode_out);
3182 file_accessed(file_in);
3183
3184 fuse_flush_time_update(inode_out);
3185
3186 return err;
3187 }
3188
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)3189 static ssize_t fuse_copy_file_range(struct file *src_file, loff_t src_off,
3190 struct file *dst_file, loff_t dst_off,
3191 size_t len, unsigned int flags)
3192 {
3193 ssize_t ret;
3194
3195 ret = __fuse_copy_file_range(src_file, src_off, dst_file, dst_off,
3196 len, flags);
3197
3198 if (ret == -EOPNOTSUPP || ret == -EXDEV)
3199 ret = splice_copy_file_range(src_file, src_off, dst_file,
3200 dst_off, len);
3201 return ret;
3202 }
3203
3204 static const struct file_operations fuse_file_operations = {
3205 .llseek = fuse_file_llseek,
3206 .read_iter = fuse_file_read_iter,
3207 .write_iter = fuse_file_write_iter,
3208 .mmap = fuse_file_mmap,
3209 .open = fuse_open,
3210 .flush = fuse_flush,
3211 .release = fuse_release,
3212 .fsync = fuse_fsync,
3213 .lock = fuse_file_lock,
3214 .get_unmapped_area = thp_get_unmapped_area,
3215 .flock = fuse_file_flock,
3216 .splice_read = filemap_splice_read,
3217 .splice_write = iter_file_splice_write,
3218 .unlocked_ioctl = fuse_file_ioctl,
3219 .compat_ioctl = fuse_file_compat_ioctl,
3220 .poll = fuse_file_poll,
3221 .fallocate = fuse_file_fallocate,
3222 .copy_file_range = fuse_copy_file_range,
3223 };
3224
3225 static const struct address_space_operations fuse_file_aops = {
3226 .read_folio = fuse_read_folio,
3227 .readahead = fuse_readahead,
3228 .writepage = fuse_writepage,
3229 .writepages = fuse_writepages,
3230 .launder_folio = fuse_launder_folio,
3231 .dirty_folio = filemap_dirty_folio,
3232 .bmap = fuse_bmap,
3233 .direct_IO = fuse_direct_IO,
3234 .write_begin = fuse_write_begin,
3235 .write_end = fuse_write_end,
3236 };
3237
fuse_init_file_inode(struct inode * inode,unsigned int flags)3238 void fuse_init_file_inode(struct inode *inode, unsigned int flags)
3239 {
3240 struct fuse_inode *fi = get_fuse_inode(inode);
3241
3242 inode->i_fop = &fuse_file_operations;
3243 inode->i_data.a_ops = &fuse_file_aops;
3244
3245 INIT_LIST_HEAD(&fi->write_files);
3246 INIT_LIST_HEAD(&fi->queued_writes);
3247 fi->writectr = 0;
3248 init_waitqueue_head(&fi->page_waitq);
3249 fi->writepages = RB_ROOT;
3250
3251 if (IS_ENABLED(CONFIG_FUSE_DAX))
3252 fuse_dax_inode_init(inode, flags);
3253 }
3254