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[deliverable/linux.git] / fs / fuse / file.c
1 /*
2 FUSE: Filesystem in Userspace
3 Copyright (C) 2001-2008 Miklos Szeredi <miklos@szeredi.hu>
4
5 This program can be distributed under the terms of the GNU GPL.
6 See the file COPYING.
7 */
8
9 #include "fuse_i.h"
10
11 #include <linux/pagemap.h>
12 #include <linux/slab.h>
13 #include <linux/kernel.h>
14 #include <linux/sched.h>
15
16 static const struct file_operations fuse_direct_io_file_operations;
17
18 static int fuse_send_open(struct inode *inode, struct file *file, int isdir,
19 struct fuse_open_out *outargp)
20 {
21 struct fuse_conn *fc = get_fuse_conn(inode);
22 struct fuse_open_in inarg;
23 struct fuse_req *req;
24 int err;
25
26 req = fuse_get_req(fc);
27 if (IS_ERR(req))
28 return PTR_ERR(req);
29
30 memset(&inarg, 0, sizeof(inarg));
31 inarg.flags = file->f_flags & ~(O_CREAT | O_EXCL | O_NOCTTY);
32 if (!fc->atomic_o_trunc)
33 inarg.flags &= ~O_TRUNC;
34 req->in.h.opcode = isdir ? FUSE_OPENDIR : FUSE_OPEN;
35 req->in.h.nodeid = get_node_id(inode);
36 req->in.numargs = 1;
37 req->in.args[0].size = sizeof(inarg);
38 req->in.args[0].value = &inarg;
39 req->out.numargs = 1;
40 req->out.args[0].size = sizeof(*outargp);
41 req->out.args[0].value = outargp;
42 fuse_request_send(fc, req);
43 err = req->out.h.error;
44 fuse_put_request(fc, req);
45
46 return err;
47 }
48
49 struct fuse_file *fuse_file_alloc(struct fuse_conn *fc)
50 {
51 struct fuse_file *ff;
52 ff = kmalloc(sizeof(struct fuse_file), GFP_KERNEL);
53 if (ff) {
54 ff->reserved_req = fuse_request_alloc();
55 if (!ff->reserved_req) {
56 kfree(ff);
57 return NULL;
58 } else {
59 INIT_LIST_HEAD(&ff->write_entry);
60 atomic_set(&ff->count, 0);
61 spin_lock(&fc->lock);
62 ff->kh = ++fc->khctr;
63 spin_unlock(&fc->lock);
64 }
65 RB_CLEAR_NODE(&ff->polled_node);
66 init_waitqueue_head(&ff->poll_wait);
67 }
68 return ff;
69 }
70
71 void fuse_file_free(struct fuse_file *ff)
72 {
73 fuse_request_free(ff->reserved_req);
74 kfree(ff);
75 }
76
77 static struct fuse_file *fuse_file_get(struct fuse_file *ff)
78 {
79 atomic_inc(&ff->count);
80 return ff;
81 }
82
83 static void fuse_release_end(struct fuse_conn *fc, struct fuse_req *req)
84 {
85 dput(req->misc.release.dentry);
86 mntput(req->misc.release.vfsmount);
87 }
88
89 static void fuse_file_put(struct fuse_file *ff)
90 {
91 if (atomic_dec_and_test(&ff->count)) {
92 struct fuse_req *req = ff->reserved_req;
93 struct inode *inode = req->misc.release.dentry->d_inode;
94 struct fuse_conn *fc = get_fuse_conn(inode);
95 req->end = fuse_release_end;
96 fuse_request_send_background(fc, req);
97 kfree(ff);
98 }
99 }
100
101 void fuse_finish_open(struct inode *inode, struct file *file,
102 struct fuse_file *ff, struct fuse_open_out *outarg)
103 {
104 if (outarg->open_flags & FOPEN_DIRECT_IO)
105 file->f_op = &fuse_direct_io_file_operations;
106 if (!(outarg->open_flags & FOPEN_KEEP_CACHE))
107 invalidate_inode_pages2(inode->i_mapping);
108 if (outarg->open_flags & FOPEN_NONSEEKABLE)
109 nonseekable_open(inode, file);
110 ff->fh = outarg->fh;
111 file->private_data = fuse_file_get(ff);
112 }
113
114 int fuse_open_common(struct inode *inode, struct file *file, int isdir)
115 {
116 struct fuse_conn *fc = get_fuse_conn(inode);
117 struct fuse_open_out outarg;
118 struct fuse_file *ff;
119 int err;
120
121 /* VFS checks this, but only _after_ ->open() */
122 if (file->f_flags & O_DIRECT)
123 return -EINVAL;
124
125 err = generic_file_open(inode, file);
126 if (err)
127 return err;
128
129 ff = fuse_file_alloc(fc);
130 if (!ff)
131 return -ENOMEM;
132
133 err = fuse_send_open(inode, file, isdir, &outarg);
134 if (err)
135 fuse_file_free(ff);
136 else {
137 if (isdir)
138 outarg.open_flags &= ~FOPEN_DIRECT_IO;
139 fuse_finish_open(inode, file, ff, &outarg);
140 }
141
142 return err;
143 }
144
145 void fuse_release_fill(struct fuse_file *ff, u64 nodeid, int flags, int opcode)
146 {
147 struct fuse_req *req = ff->reserved_req;
148 struct fuse_release_in *inarg = &req->misc.release.in;
149
150 inarg->fh = ff->fh;
151 inarg->flags = flags;
152 req->in.h.opcode = opcode;
153 req->in.h.nodeid = nodeid;
154 req->in.numargs = 1;
155 req->in.args[0].size = sizeof(struct fuse_release_in);
156 req->in.args[0].value = inarg;
157 }
158
159 int fuse_release_common(struct inode *inode, struct file *file, int isdir)
160 {
161 struct fuse_file *ff = file->private_data;
162 if (ff) {
163 struct fuse_conn *fc = get_fuse_conn(inode);
164 struct fuse_req *req = ff->reserved_req;
165
166 fuse_release_fill(ff, get_node_id(inode), file->f_flags,
167 isdir ? FUSE_RELEASEDIR : FUSE_RELEASE);
168
169 /* Hold vfsmount and dentry until release is finished */
170 req->misc.release.vfsmount = mntget(file->f_path.mnt);
171 req->misc.release.dentry = dget(file->f_path.dentry);
172
173 spin_lock(&fc->lock);
174 list_del(&ff->write_entry);
175 if (!RB_EMPTY_NODE(&ff->polled_node))
176 rb_erase(&ff->polled_node, &fc->polled_files);
177 spin_unlock(&fc->lock);
178
179 wake_up_interruptible_sync(&ff->poll_wait);
180 /*
181 * Normally this will send the RELEASE request,
182 * however if some asynchronous READ or WRITE requests
183 * are outstanding, the sending will be delayed
184 */
185 fuse_file_put(ff);
186 }
187
188 /* Return value is ignored by VFS */
189 return 0;
190 }
191
192 static int fuse_open(struct inode *inode, struct file *file)
193 {
194 return fuse_open_common(inode, file, 0);
195 }
196
197 static int fuse_release(struct inode *inode, struct file *file)
198 {
199 return fuse_release_common(inode, file, 0);
200 }
201
202 /*
203 * Scramble the ID space with XTEA, so that the value of the files_struct
204 * pointer is not exposed to userspace.
205 */
206 u64 fuse_lock_owner_id(struct fuse_conn *fc, fl_owner_t id)
207 {
208 u32 *k = fc->scramble_key;
209 u64 v = (unsigned long) id;
210 u32 v0 = v;
211 u32 v1 = v >> 32;
212 u32 sum = 0;
213 int i;
214
215 for (i = 0; i < 32; i++) {
216 v0 += ((v1 << 4 ^ v1 >> 5) + v1) ^ (sum + k[sum & 3]);
217 sum += 0x9E3779B9;
218 v1 += ((v0 << 4 ^ v0 >> 5) + v0) ^ (sum + k[sum>>11 & 3]);
219 }
220
221 return (u64) v0 + ((u64) v1 << 32);
222 }
223
224 /*
225 * Check if page is under writeback
226 *
227 * This is currently done by walking the list of writepage requests
228 * for the inode, which can be pretty inefficient.
229 */
230 static bool fuse_page_is_writeback(struct inode *inode, pgoff_t index)
231 {
232 struct fuse_conn *fc = get_fuse_conn(inode);
233 struct fuse_inode *fi = get_fuse_inode(inode);
234 struct fuse_req *req;
235 bool found = false;
236
237 spin_lock(&fc->lock);
238 list_for_each_entry(req, &fi->writepages, writepages_entry) {
239 pgoff_t curr_index;
240
241 BUG_ON(req->inode != inode);
242 curr_index = req->misc.write.in.offset >> PAGE_CACHE_SHIFT;
243 if (curr_index == index) {
244 found = true;
245 break;
246 }
247 }
248 spin_unlock(&fc->lock);
249
250 return found;
251 }
252
253 /*
254 * Wait for page writeback to be completed.
255 *
256 * Since fuse doesn't rely on the VM writeback tracking, this has to
257 * use some other means.
258 */
259 static int fuse_wait_on_page_writeback(struct inode *inode, pgoff_t index)
260 {
261 struct fuse_inode *fi = get_fuse_inode(inode);
262
263 wait_event(fi->page_waitq, !fuse_page_is_writeback(inode, index));
264 return 0;
265 }
266
267 static int fuse_flush(struct file *file, fl_owner_t id)
268 {
269 struct inode *inode = file->f_path.dentry->d_inode;
270 struct fuse_conn *fc = get_fuse_conn(inode);
271 struct fuse_file *ff = file->private_data;
272 struct fuse_req *req;
273 struct fuse_flush_in inarg;
274 int err;
275
276 if (is_bad_inode(inode))
277 return -EIO;
278
279 if (fc->no_flush)
280 return 0;
281
282 req = fuse_get_req_nofail(fc, file);
283 memset(&inarg, 0, sizeof(inarg));
284 inarg.fh = ff->fh;
285 inarg.lock_owner = fuse_lock_owner_id(fc, id);
286 req->in.h.opcode = FUSE_FLUSH;
287 req->in.h.nodeid = get_node_id(inode);
288 req->in.numargs = 1;
289 req->in.args[0].size = sizeof(inarg);
290 req->in.args[0].value = &inarg;
291 req->force = 1;
292 fuse_request_send(fc, req);
293 err = req->out.h.error;
294 fuse_put_request(fc, req);
295 if (err == -ENOSYS) {
296 fc->no_flush = 1;
297 err = 0;
298 }
299 return err;
300 }
301
302 /*
303 * Wait for all pending writepages on the inode to finish.
304 *
305 * This is currently done by blocking further writes with FUSE_NOWRITE
306 * and waiting for all sent writes to complete.
307 *
308 * This must be called under i_mutex, otherwise the FUSE_NOWRITE usage
309 * could conflict with truncation.
310 */
311 static void fuse_sync_writes(struct inode *inode)
312 {
313 fuse_set_nowrite(inode);
314 fuse_release_nowrite(inode);
315 }
316
317 int fuse_fsync_common(struct file *file, struct dentry *de, int datasync,
318 int isdir)
319 {
320 struct inode *inode = de->d_inode;
321 struct fuse_conn *fc = get_fuse_conn(inode);
322 struct fuse_file *ff = file->private_data;
323 struct fuse_req *req;
324 struct fuse_fsync_in inarg;
325 int err;
326
327 if (is_bad_inode(inode))
328 return -EIO;
329
330 if ((!isdir && fc->no_fsync) || (isdir && fc->no_fsyncdir))
331 return 0;
332
333 /*
334 * Start writeback against all dirty pages of the inode, then
335 * wait for all outstanding writes, before sending the FSYNC
336 * request.
337 */
338 err = write_inode_now(inode, 0);
339 if (err)
340 return err;
341
342 fuse_sync_writes(inode);
343
344 req = fuse_get_req(fc);
345 if (IS_ERR(req))
346 return PTR_ERR(req);
347
348 memset(&inarg, 0, sizeof(inarg));
349 inarg.fh = ff->fh;
350 inarg.fsync_flags = datasync ? 1 : 0;
351 req->in.h.opcode = isdir ? FUSE_FSYNCDIR : FUSE_FSYNC;
352 req->in.h.nodeid = get_node_id(inode);
353 req->in.numargs = 1;
354 req->in.args[0].size = sizeof(inarg);
355 req->in.args[0].value = &inarg;
356 fuse_request_send(fc, req);
357 err = req->out.h.error;
358 fuse_put_request(fc, req);
359 if (err == -ENOSYS) {
360 if (isdir)
361 fc->no_fsyncdir = 1;
362 else
363 fc->no_fsync = 1;
364 err = 0;
365 }
366 return err;
367 }
368
369 static int fuse_fsync(struct file *file, struct dentry *de, int datasync)
370 {
371 return fuse_fsync_common(file, de, datasync, 0);
372 }
373
374 void fuse_read_fill(struct fuse_req *req, struct file *file,
375 struct inode *inode, loff_t pos, size_t count, int opcode)
376 {
377 struct fuse_read_in *inarg = &req->misc.read.in;
378 struct fuse_file *ff = file->private_data;
379
380 inarg->fh = ff->fh;
381 inarg->offset = pos;
382 inarg->size = count;
383 inarg->flags = file->f_flags;
384 req->in.h.opcode = opcode;
385 req->in.h.nodeid = get_node_id(inode);
386 req->in.numargs = 1;
387 req->in.args[0].size = sizeof(struct fuse_read_in);
388 req->in.args[0].value = inarg;
389 req->out.argvar = 1;
390 req->out.numargs = 1;
391 req->out.args[0].size = count;
392 }
393
394 static size_t fuse_send_read(struct fuse_req *req, struct file *file,
395 struct inode *inode, loff_t pos, size_t count,
396 fl_owner_t owner)
397 {
398 struct fuse_conn *fc = get_fuse_conn(inode);
399
400 fuse_read_fill(req, file, inode, pos, count, FUSE_READ);
401 if (owner != NULL) {
402 struct fuse_read_in *inarg = &req->misc.read.in;
403
404 inarg->read_flags |= FUSE_READ_LOCKOWNER;
405 inarg->lock_owner = fuse_lock_owner_id(fc, owner);
406 }
407 fuse_request_send(fc, req);
408 return req->out.args[0].size;
409 }
410
411 static void fuse_read_update_size(struct inode *inode, loff_t size,
412 u64 attr_ver)
413 {
414 struct fuse_conn *fc = get_fuse_conn(inode);
415 struct fuse_inode *fi = get_fuse_inode(inode);
416
417 spin_lock(&fc->lock);
418 if (attr_ver == fi->attr_version && size < inode->i_size) {
419 fi->attr_version = ++fc->attr_version;
420 i_size_write(inode, size);
421 }
422 spin_unlock(&fc->lock);
423 }
424
425 static int fuse_readpage(struct file *file, struct page *page)
426 {
427 struct inode *inode = page->mapping->host;
428 struct fuse_conn *fc = get_fuse_conn(inode);
429 struct fuse_req *req;
430 size_t num_read;
431 loff_t pos = page_offset(page);
432 size_t count = PAGE_CACHE_SIZE;
433 u64 attr_ver;
434 int err;
435
436 err = -EIO;
437 if (is_bad_inode(inode))
438 goto out;
439
440 /*
441 * Page writeback can extend beyond the liftime of the
442 * page-cache page, so make sure we read a properly synced
443 * page.
444 */
445 fuse_wait_on_page_writeback(inode, page->index);
446
447 req = fuse_get_req(fc);
448 err = PTR_ERR(req);
449 if (IS_ERR(req))
450 goto out;
451
452 attr_ver = fuse_get_attr_version(fc);
453
454 req->out.page_zeroing = 1;
455 req->out.argpages = 1;
456 req->num_pages = 1;
457 req->pages[0] = page;
458 num_read = fuse_send_read(req, file, inode, pos, count, NULL);
459 err = req->out.h.error;
460 fuse_put_request(fc, req);
461
462 if (!err) {
463 /*
464 * Short read means EOF. If file size is larger, truncate it
465 */
466 if (num_read < count)
467 fuse_read_update_size(inode, pos + num_read, attr_ver);
468
469 SetPageUptodate(page);
470 }
471
472 fuse_invalidate_attr(inode); /* atime changed */
473 out:
474 unlock_page(page);
475 return err;
476 }
477
478 static void fuse_readpages_end(struct fuse_conn *fc, struct fuse_req *req)
479 {
480 int i;
481 size_t count = req->misc.read.in.size;
482 size_t num_read = req->out.args[0].size;
483 struct inode *inode = req->pages[0]->mapping->host;
484
485 /*
486 * Short read means EOF. If file size is larger, truncate it
487 */
488 if (!req->out.h.error && num_read < count) {
489 loff_t pos = page_offset(req->pages[0]) + num_read;
490 fuse_read_update_size(inode, pos, req->misc.read.attr_ver);
491 }
492
493 fuse_invalidate_attr(inode); /* atime changed */
494
495 for (i = 0; i < req->num_pages; i++) {
496 struct page *page = req->pages[i];
497 if (!req->out.h.error)
498 SetPageUptodate(page);
499 else
500 SetPageError(page);
501 unlock_page(page);
502 }
503 if (req->ff)
504 fuse_file_put(req->ff);
505 }
506
507 static void fuse_send_readpages(struct fuse_req *req, struct file *file,
508 struct inode *inode)
509 {
510 struct fuse_conn *fc = get_fuse_conn(inode);
511 loff_t pos = page_offset(req->pages[0]);
512 size_t count = req->num_pages << PAGE_CACHE_SHIFT;
513
514 req->out.argpages = 1;
515 req->out.page_zeroing = 1;
516 fuse_read_fill(req, file, inode, pos, count, FUSE_READ);
517 req->misc.read.attr_ver = fuse_get_attr_version(fc);
518 if (fc->async_read) {
519 struct fuse_file *ff = file->private_data;
520 req->ff = fuse_file_get(ff);
521 req->end = fuse_readpages_end;
522 fuse_request_send_background(fc, req);
523 } else {
524 fuse_request_send(fc, req);
525 fuse_readpages_end(fc, req);
526 fuse_put_request(fc, req);
527 }
528 }
529
530 struct fuse_fill_data {
531 struct fuse_req *req;
532 struct file *file;
533 struct inode *inode;
534 };
535
536 static int fuse_readpages_fill(void *_data, struct page *page)
537 {
538 struct fuse_fill_data *data = _data;
539 struct fuse_req *req = data->req;
540 struct inode *inode = data->inode;
541 struct fuse_conn *fc = get_fuse_conn(inode);
542
543 fuse_wait_on_page_writeback(inode, page->index);
544
545 if (req->num_pages &&
546 (req->num_pages == FUSE_MAX_PAGES_PER_REQ ||
547 (req->num_pages + 1) * PAGE_CACHE_SIZE > fc->max_read ||
548 req->pages[req->num_pages - 1]->index + 1 != page->index)) {
549 fuse_send_readpages(req, data->file, inode);
550 data->req = req = fuse_get_req(fc);
551 if (IS_ERR(req)) {
552 unlock_page(page);
553 return PTR_ERR(req);
554 }
555 }
556 req->pages[req->num_pages] = page;
557 req->num_pages++;
558 return 0;
559 }
560
561 static int fuse_readpages(struct file *file, struct address_space *mapping,
562 struct list_head *pages, unsigned nr_pages)
563 {
564 struct inode *inode = mapping->host;
565 struct fuse_conn *fc = get_fuse_conn(inode);
566 struct fuse_fill_data data;
567 int err;
568
569 err = -EIO;
570 if (is_bad_inode(inode))
571 goto out;
572
573 data.file = file;
574 data.inode = inode;
575 data.req = fuse_get_req(fc);
576 err = PTR_ERR(data.req);
577 if (IS_ERR(data.req))
578 goto out;
579
580 err = read_cache_pages(mapping, pages, fuse_readpages_fill, &data);
581 if (!err) {
582 if (data.req->num_pages)
583 fuse_send_readpages(data.req, file, inode);
584 else
585 fuse_put_request(fc, data.req);
586 }
587 out:
588 return err;
589 }
590
591 static ssize_t fuse_file_aio_read(struct kiocb *iocb, const struct iovec *iov,
592 unsigned long nr_segs, loff_t pos)
593 {
594 struct inode *inode = iocb->ki_filp->f_mapping->host;
595
596 if (pos + iov_length(iov, nr_segs) > i_size_read(inode)) {
597 int err;
598 /*
599 * If trying to read past EOF, make sure the i_size
600 * attribute is up-to-date.
601 */
602 err = fuse_update_attributes(inode, NULL, iocb->ki_filp, NULL);
603 if (err)
604 return err;
605 }
606
607 return generic_file_aio_read(iocb, iov, nr_segs, pos);
608 }
609
610 static void fuse_write_fill(struct fuse_req *req, struct file *file,
611 struct fuse_file *ff, struct inode *inode,
612 loff_t pos, size_t count, int writepage)
613 {
614 struct fuse_conn *fc = get_fuse_conn(inode);
615 struct fuse_write_in *inarg = &req->misc.write.in;
616 struct fuse_write_out *outarg = &req->misc.write.out;
617
618 memset(inarg, 0, sizeof(struct fuse_write_in));
619 inarg->fh = ff->fh;
620 inarg->offset = pos;
621 inarg->size = count;
622 inarg->write_flags = writepage ? FUSE_WRITE_CACHE : 0;
623 inarg->flags = file ? file->f_flags : 0;
624 req->in.h.opcode = FUSE_WRITE;
625 req->in.h.nodeid = get_node_id(inode);
626 req->in.numargs = 2;
627 if (fc->minor < 9)
628 req->in.args[0].size = FUSE_COMPAT_WRITE_IN_SIZE;
629 else
630 req->in.args[0].size = sizeof(struct fuse_write_in);
631 req->in.args[0].value = inarg;
632 req->in.args[1].size = count;
633 req->out.numargs = 1;
634 req->out.args[0].size = sizeof(struct fuse_write_out);
635 req->out.args[0].value = outarg;
636 }
637
638 static size_t fuse_send_write(struct fuse_req *req, struct file *file,
639 struct inode *inode, loff_t pos, size_t count,
640 fl_owner_t owner)
641 {
642 struct fuse_conn *fc = get_fuse_conn(inode);
643 fuse_write_fill(req, file, file->private_data, inode, pos, count, 0);
644 if (owner != NULL) {
645 struct fuse_write_in *inarg = &req->misc.write.in;
646 inarg->write_flags |= FUSE_WRITE_LOCKOWNER;
647 inarg->lock_owner = fuse_lock_owner_id(fc, owner);
648 }
649 fuse_request_send(fc, req);
650 return req->misc.write.out.size;
651 }
652
653 static int fuse_write_begin(struct file *file, struct address_space *mapping,
654 loff_t pos, unsigned len, unsigned flags,
655 struct page **pagep, void **fsdata)
656 {
657 pgoff_t index = pos >> PAGE_CACHE_SHIFT;
658
659 *pagep = grab_cache_page_write_begin(mapping, index, flags);
660 if (!*pagep)
661 return -ENOMEM;
662 return 0;
663 }
664
665 static void fuse_write_update_size(struct inode *inode, loff_t pos)
666 {
667 struct fuse_conn *fc = get_fuse_conn(inode);
668 struct fuse_inode *fi = get_fuse_inode(inode);
669
670 spin_lock(&fc->lock);
671 fi->attr_version = ++fc->attr_version;
672 if (pos > inode->i_size)
673 i_size_write(inode, pos);
674 spin_unlock(&fc->lock);
675 }
676
677 static int fuse_buffered_write(struct file *file, struct inode *inode,
678 loff_t pos, unsigned count, struct page *page)
679 {
680 int err;
681 size_t nres;
682 struct fuse_conn *fc = get_fuse_conn(inode);
683 unsigned offset = pos & (PAGE_CACHE_SIZE - 1);
684 struct fuse_req *req;
685
686 if (is_bad_inode(inode))
687 return -EIO;
688
689 /*
690 * Make sure writepages on the same page are not mixed up with
691 * plain writes.
692 */
693 fuse_wait_on_page_writeback(inode, page->index);
694
695 req = fuse_get_req(fc);
696 if (IS_ERR(req))
697 return PTR_ERR(req);
698
699 req->in.argpages = 1;
700 req->num_pages = 1;
701 req->pages[0] = page;
702 req->page_offset = offset;
703 nres = fuse_send_write(req, file, inode, pos, count, NULL);
704 err = req->out.h.error;
705 fuse_put_request(fc, req);
706 if (!err && !nres)
707 err = -EIO;
708 if (!err) {
709 pos += nres;
710 fuse_write_update_size(inode, pos);
711 if (count == PAGE_CACHE_SIZE)
712 SetPageUptodate(page);
713 }
714 fuse_invalidate_attr(inode);
715 return err ? err : nres;
716 }
717
718 static int fuse_write_end(struct file *file, struct address_space *mapping,
719 loff_t pos, unsigned len, unsigned copied,
720 struct page *page, void *fsdata)
721 {
722 struct inode *inode = mapping->host;
723 int res = 0;
724
725 if (copied)
726 res = fuse_buffered_write(file, inode, pos, copied, page);
727
728 unlock_page(page);
729 page_cache_release(page);
730 return res;
731 }
732
733 static size_t fuse_send_write_pages(struct fuse_req *req, struct file *file,
734 struct inode *inode, loff_t pos,
735 size_t count)
736 {
737 size_t res;
738 unsigned offset;
739 unsigned i;
740
741 for (i = 0; i < req->num_pages; i++)
742 fuse_wait_on_page_writeback(inode, req->pages[i]->index);
743
744 res = fuse_send_write(req, file, inode, pos, count, NULL);
745
746 offset = req->page_offset;
747 count = res;
748 for (i = 0; i < req->num_pages; i++) {
749 struct page *page = req->pages[i];
750
751 if (!req->out.h.error && !offset && count >= PAGE_CACHE_SIZE)
752 SetPageUptodate(page);
753
754 if (count > PAGE_CACHE_SIZE - offset)
755 count -= PAGE_CACHE_SIZE - offset;
756 else
757 count = 0;
758 offset = 0;
759
760 unlock_page(page);
761 page_cache_release(page);
762 }
763
764 return res;
765 }
766
767 static ssize_t fuse_fill_write_pages(struct fuse_req *req,
768 struct address_space *mapping,
769 struct iov_iter *ii, loff_t pos)
770 {
771 struct fuse_conn *fc = get_fuse_conn(mapping->host);
772 unsigned offset = pos & (PAGE_CACHE_SIZE - 1);
773 size_t count = 0;
774 int err;
775
776 req->in.argpages = 1;
777 req->page_offset = offset;
778
779 do {
780 size_t tmp;
781 struct page *page;
782 pgoff_t index = pos >> PAGE_CACHE_SHIFT;
783 size_t bytes = min_t(size_t, PAGE_CACHE_SIZE - offset,
784 iov_iter_count(ii));
785
786 bytes = min_t(size_t, bytes, fc->max_write - count);
787
788 again:
789 err = -EFAULT;
790 if (iov_iter_fault_in_readable(ii, bytes))
791 break;
792
793 err = -ENOMEM;
794 page = grab_cache_page_write_begin(mapping, index, 0);
795 if (!page)
796 break;
797
798 pagefault_disable();
799 tmp = iov_iter_copy_from_user_atomic(page, ii, offset, bytes);
800 pagefault_enable();
801 flush_dcache_page(page);
802
803 if (!tmp) {
804 unlock_page(page);
805 page_cache_release(page);
806 bytes = min(bytes, iov_iter_single_seg_count(ii));
807 goto again;
808 }
809
810 err = 0;
811 req->pages[req->num_pages] = page;
812 req->num_pages++;
813
814 iov_iter_advance(ii, tmp);
815 count += tmp;
816 pos += tmp;
817 offset += tmp;
818 if (offset == PAGE_CACHE_SIZE)
819 offset = 0;
820
821 if (!fc->big_writes)
822 break;
823 } while (iov_iter_count(ii) && count < fc->max_write &&
824 req->num_pages < FUSE_MAX_PAGES_PER_REQ && offset == 0);
825
826 return count > 0 ? count : err;
827 }
828
829 static ssize_t fuse_perform_write(struct file *file,
830 struct address_space *mapping,
831 struct iov_iter *ii, loff_t pos)
832 {
833 struct inode *inode = mapping->host;
834 struct fuse_conn *fc = get_fuse_conn(inode);
835 int err = 0;
836 ssize_t res = 0;
837
838 if (is_bad_inode(inode))
839 return -EIO;
840
841 do {
842 struct fuse_req *req;
843 ssize_t count;
844
845 req = fuse_get_req(fc);
846 if (IS_ERR(req)) {
847 err = PTR_ERR(req);
848 break;
849 }
850
851 count = fuse_fill_write_pages(req, mapping, ii, pos);
852 if (count <= 0) {
853 err = count;
854 } else {
855 size_t num_written;
856
857 num_written = fuse_send_write_pages(req, file, inode,
858 pos, count);
859 err = req->out.h.error;
860 if (!err) {
861 res += num_written;
862 pos += num_written;
863
864 /* break out of the loop on short write */
865 if (num_written != count)
866 err = -EIO;
867 }
868 }
869 fuse_put_request(fc, req);
870 } while (!err && iov_iter_count(ii));
871
872 if (res > 0)
873 fuse_write_update_size(inode, pos);
874
875 fuse_invalidate_attr(inode);
876
877 return res > 0 ? res : err;
878 }
879
880 static ssize_t fuse_file_aio_write(struct kiocb *iocb, const struct iovec *iov,
881 unsigned long nr_segs, loff_t pos)
882 {
883 struct file *file = iocb->ki_filp;
884 struct address_space *mapping = file->f_mapping;
885 size_t count = 0;
886 ssize_t written = 0;
887 struct inode *inode = mapping->host;
888 ssize_t err;
889 struct iov_iter i;
890
891 WARN_ON(iocb->ki_pos != pos);
892
893 err = generic_segment_checks(iov, &nr_segs, &count, VERIFY_READ);
894 if (err)
895 return err;
896
897 mutex_lock(&inode->i_mutex);
898 vfs_check_frozen(inode->i_sb, SB_FREEZE_WRITE);
899
900 /* We can write back this queue in page reclaim */
901 current->backing_dev_info = mapping->backing_dev_info;
902
903 err = generic_write_checks(file, &pos, &count, S_ISBLK(inode->i_mode));
904 if (err)
905 goto out;
906
907 if (count == 0)
908 goto out;
909
910 err = file_remove_suid(file);
911 if (err)
912 goto out;
913
914 file_update_time(file);
915
916 iov_iter_init(&i, iov, nr_segs, count, 0);
917 written = fuse_perform_write(file, mapping, &i, pos);
918 if (written >= 0)
919 iocb->ki_pos = pos + written;
920
921 out:
922 current->backing_dev_info = NULL;
923 mutex_unlock(&inode->i_mutex);
924
925 return written ? written : err;
926 }
927
928 static void fuse_release_user_pages(struct fuse_req *req, int write)
929 {
930 unsigned i;
931
932 for (i = 0; i < req->num_pages; i++) {
933 struct page *page = req->pages[i];
934 if (write)
935 set_page_dirty_lock(page);
936 put_page(page);
937 }
938 }
939
940 static int fuse_get_user_pages(struct fuse_req *req, const char __user *buf,
941 unsigned *nbytesp, int write)
942 {
943 unsigned nbytes = *nbytesp;
944 unsigned long user_addr = (unsigned long) buf;
945 unsigned offset = user_addr & ~PAGE_MASK;
946 int npages;
947
948 /* Special case for kernel I/O: can copy directly into the buffer */
949 if (segment_eq(get_fs(), KERNEL_DS)) {
950 if (write)
951 req->in.args[1].value = (void *) user_addr;
952 else
953 req->out.args[0].value = (void *) user_addr;
954
955 return 0;
956 }
957
958 nbytes = min(nbytes, (unsigned) FUSE_MAX_PAGES_PER_REQ << PAGE_SHIFT);
959 npages = (nbytes + offset + PAGE_SIZE - 1) >> PAGE_SHIFT;
960 npages = clamp(npages, 1, FUSE_MAX_PAGES_PER_REQ);
961 down_read(&current->mm->mmap_sem);
962 npages = get_user_pages(current, current->mm, user_addr, npages, !write,
963 0, req->pages, NULL);
964 up_read(&current->mm->mmap_sem);
965 if (npages < 0)
966 return npages;
967
968 req->num_pages = npages;
969 req->page_offset = offset;
970
971 if (write)
972 req->in.argpages = 1;
973 else
974 req->out.argpages = 1;
975
976 nbytes = (req->num_pages << PAGE_SHIFT) - req->page_offset;
977 *nbytesp = min(*nbytesp, nbytes);
978
979 return 0;
980 }
981
982 static ssize_t fuse_direct_io(struct file *file, const char __user *buf,
983 size_t count, loff_t *ppos, int write)
984 {
985 struct inode *inode = file->f_path.dentry->d_inode;
986 struct fuse_conn *fc = get_fuse_conn(inode);
987 size_t nmax = write ? fc->max_write : fc->max_read;
988 loff_t pos = *ppos;
989 ssize_t res = 0;
990 struct fuse_req *req;
991
992 if (is_bad_inode(inode))
993 return -EIO;
994
995 req = fuse_get_req(fc);
996 if (IS_ERR(req))
997 return PTR_ERR(req);
998
999 while (count) {
1000 size_t nres;
1001 size_t nbytes = min(count, nmax);
1002 int err = fuse_get_user_pages(req, buf, &nbytes, write);
1003 if (err) {
1004 res = err;
1005 break;
1006 }
1007
1008 if (write)
1009 nres = fuse_send_write(req, file, inode, pos, nbytes,
1010 current->files);
1011 else
1012 nres = fuse_send_read(req, file, inode, pos, nbytes,
1013 current->files);
1014 fuse_release_user_pages(req, !write);
1015 if (req->out.h.error) {
1016 if (!res)
1017 res = req->out.h.error;
1018 break;
1019 } else if (nres > nbytes) {
1020 res = -EIO;
1021 break;
1022 }
1023 count -= nres;
1024 res += nres;
1025 pos += nres;
1026 buf += nres;
1027 if (nres != nbytes)
1028 break;
1029 if (count) {
1030 fuse_put_request(fc, req);
1031 req = fuse_get_req(fc);
1032 if (IS_ERR(req))
1033 break;
1034 }
1035 }
1036 fuse_put_request(fc, req);
1037 if (res > 0) {
1038 if (write)
1039 fuse_write_update_size(inode, pos);
1040 *ppos = pos;
1041 }
1042 fuse_invalidate_attr(inode);
1043
1044 return res;
1045 }
1046
1047 static ssize_t fuse_direct_read(struct file *file, char __user *buf,
1048 size_t count, loff_t *ppos)
1049 {
1050 return fuse_direct_io(file, buf, count, ppos, 0);
1051 }
1052
1053 static ssize_t fuse_direct_write(struct file *file, const char __user *buf,
1054 size_t count, loff_t *ppos)
1055 {
1056 struct inode *inode = file->f_path.dentry->d_inode;
1057 ssize_t res;
1058 /* Don't allow parallel writes to the same file */
1059 mutex_lock(&inode->i_mutex);
1060 res = generic_write_checks(file, ppos, &count, 0);
1061 if (!res)
1062 res = fuse_direct_io(file, buf, count, ppos, 1);
1063 mutex_unlock(&inode->i_mutex);
1064 return res;
1065 }
1066
1067 static void fuse_writepage_free(struct fuse_conn *fc, struct fuse_req *req)
1068 {
1069 __free_page(req->pages[0]);
1070 fuse_file_put(req->ff);
1071 }
1072
1073 static void fuse_writepage_finish(struct fuse_conn *fc, struct fuse_req *req)
1074 {
1075 struct inode *inode = req->inode;
1076 struct fuse_inode *fi = get_fuse_inode(inode);
1077 struct backing_dev_info *bdi = inode->i_mapping->backing_dev_info;
1078
1079 list_del(&req->writepages_entry);
1080 dec_bdi_stat(bdi, BDI_WRITEBACK);
1081 dec_zone_page_state(req->pages[0], NR_WRITEBACK_TEMP);
1082 bdi_writeout_inc(bdi);
1083 wake_up(&fi->page_waitq);
1084 }
1085
1086 /* Called under fc->lock, may release and reacquire it */
1087 static void fuse_send_writepage(struct fuse_conn *fc, struct fuse_req *req)
1088 __releases(&fc->lock)
1089 __acquires(&fc->lock)
1090 {
1091 struct fuse_inode *fi = get_fuse_inode(req->inode);
1092 loff_t size = i_size_read(req->inode);
1093 struct fuse_write_in *inarg = &req->misc.write.in;
1094
1095 if (!fc->connected)
1096 goto out_free;
1097
1098 if (inarg->offset + PAGE_CACHE_SIZE <= size) {
1099 inarg->size = PAGE_CACHE_SIZE;
1100 } else if (inarg->offset < size) {
1101 inarg->size = size & (PAGE_CACHE_SIZE - 1);
1102 } else {
1103 /* Got truncated off completely */
1104 goto out_free;
1105 }
1106
1107 req->in.args[1].size = inarg->size;
1108 fi->writectr++;
1109 fuse_request_send_background_locked(fc, req);
1110 return;
1111
1112 out_free:
1113 fuse_writepage_finish(fc, req);
1114 spin_unlock(&fc->lock);
1115 fuse_writepage_free(fc, req);
1116 fuse_put_request(fc, req);
1117 spin_lock(&fc->lock);
1118 }
1119
1120 /*
1121 * If fi->writectr is positive (no truncate or fsync going on) send
1122 * all queued writepage requests.
1123 *
1124 * Called with fc->lock
1125 */
1126 void fuse_flush_writepages(struct inode *inode)
1127 __releases(&fc->lock)
1128 __acquires(&fc->lock)
1129 {
1130 struct fuse_conn *fc = get_fuse_conn(inode);
1131 struct fuse_inode *fi = get_fuse_inode(inode);
1132 struct fuse_req *req;
1133
1134 while (fi->writectr >= 0 && !list_empty(&fi->queued_writes)) {
1135 req = list_entry(fi->queued_writes.next, struct fuse_req, list);
1136 list_del_init(&req->list);
1137 fuse_send_writepage(fc, req);
1138 }
1139 }
1140
1141 static void fuse_writepage_end(struct fuse_conn *fc, struct fuse_req *req)
1142 {
1143 struct inode *inode = req->inode;
1144 struct fuse_inode *fi = get_fuse_inode(inode);
1145
1146 mapping_set_error(inode->i_mapping, req->out.h.error);
1147 spin_lock(&fc->lock);
1148 fi->writectr--;
1149 fuse_writepage_finish(fc, req);
1150 spin_unlock(&fc->lock);
1151 fuse_writepage_free(fc, req);
1152 }
1153
1154 static int fuse_writepage_locked(struct page *page)
1155 {
1156 struct address_space *mapping = page->mapping;
1157 struct inode *inode = mapping->host;
1158 struct fuse_conn *fc = get_fuse_conn(inode);
1159 struct fuse_inode *fi = get_fuse_inode(inode);
1160 struct fuse_req *req;
1161 struct fuse_file *ff;
1162 struct page *tmp_page;
1163
1164 set_page_writeback(page);
1165
1166 req = fuse_request_alloc_nofs();
1167 if (!req)
1168 goto err;
1169
1170 tmp_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
1171 if (!tmp_page)
1172 goto err_free;
1173
1174 spin_lock(&fc->lock);
1175 BUG_ON(list_empty(&fi->write_files));
1176 ff = list_entry(fi->write_files.next, struct fuse_file, write_entry);
1177 req->ff = fuse_file_get(ff);
1178 spin_unlock(&fc->lock);
1179
1180 fuse_write_fill(req, NULL, ff, inode, page_offset(page), 0, 1);
1181
1182 copy_highpage(tmp_page, page);
1183 req->in.argpages = 1;
1184 req->num_pages = 1;
1185 req->pages[0] = tmp_page;
1186 req->page_offset = 0;
1187 req->end = fuse_writepage_end;
1188 req->inode = inode;
1189
1190 inc_bdi_stat(mapping->backing_dev_info, BDI_WRITEBACK);
1191 inc_zone_page_state(tmp_page, NR_WRITEBACK_TEMP);
1192 end_page_writeback(page);
1193
1194 spin_lock(&fc->lock);
1195 list_add(&req->writepages_entry, &fi->writepages);
1196 list_add_tail(&req->list, &fi->queued_writes);
1197 fuse_flush_writepages(inode);
1198 spin_unlock(&fc->lock);
1199
1200 return 0;
1201
1202 err_free:
1203 fuse_request_free(req);
1204 err:
1205 end_page_writeback(page);
1206 return -ENOMEM;
1207 }
1208
1209 static int fuse_writepage(struct page *page, struct writeback_control *wbc)
1210 {
1211 int err;
1212
1213 err = fuse_writepage_locked(page);
1214 unlock_page(page);
1215
1216 return err;
1217 }
1218
1219 static int fuse_launder_page(struct page *page)
1220 {
1221 int err = 0;
1222 if (clear_page_dirty_for_io(page)) {
1223 struct inode *inode = page->mapping->host;
1224 err = fuse_writepage_locked(page);
1225 if (!err)
1226 fuse_wait_on_page_writeback(inode, page->index);
1227 }
1228 return err;
1229 }
1230
1231 /*
1232 * Write back dirty pages now, because there may not be any suitable
1233 * open files later
1234 */
1235 static void fuse_vma_close(struct vm_area_struct *vma)
1236 {
1237 filemap_write_and_wait(vma->vm_file->f_mapping);
1238 }
1239
1240 /*
1241 * Wait for writeback against this page to complete before allowing it
1242 * to be marked dirty again, and hence written back again, possibly
1243 * before the previous writepage completed.
1244 *
1245 * Block here, instead of in ->writepage(), so that the userspace fs
1246 * can only block processes actually operating on the filesystem.
1247 *
1248 * Otherwise unprivileged userspace fs would be able to block
1249 * unrelated:
1250 *
1251 * - page migration
1252 * - sync(2)
1253 * - try_to_free_pages() with order > PAGE_ALLOC_COSTLY_ORDER
1254 */
1255 static int fuse_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
1256 {
1257 struct page *page = vmf->page;
1258 /*
1259 * Don't use page->mapping as it may become NULL from a
1260 * concurrent truncate.
1261 */
1262 struct inode *inode = vma->vm_file->f_mapping->host;
1263
1264 fuse_wait_on_page_writeback(inode, page->index);
1265 return 0;
1266 }
1267
1268 static struct vm_operations_struct fuse_file_vm_ops = {
1269 .close = fuse_vma_close,
1270 .fault = filemap_fault,
1271 .page_mkwrite = fuse_page_mkwrite,
1272 };
1273
1274 static int fuse_file_mmap(struct file *file, struct vm_area_struct *vma)
1275 {
1276 if ((vma->vm_flags & VM_SHARED) && (vma->vm_flags & VM_MAYWRITE)) {
1277 struct inode *inode = file->f_dentry->d_inode;
1278 struct fuse_conn *fc = get_fuse_conn(inode);
1279 struct fuse_inode *fi = get_fuse_inode(inode);
1280 struct fuse_file *ff = file->private_data;
1281 /*
1282 * file may be written through mmap, so chain it onto the
1283 * inodes's write_file list
1284 */
1285 spin_lock(&fc->lock);
1286 if (list_empty(&ff->write_entry))
1287 list_add(&ff->write_entry, &fi->write_files);
1288 spin_unlock(&fc->lock);
1289 }
1290 file_accessed(file);
1291 vma->vm_ops = &fuse_file_vm_ops;
1292 return 0;
1293 }
1294
1295 static int convert_fuse_file_lock(const struct fuse_file_lock *ffl,
1296 struct file_lock *fl)
1297 {
1298 switch (ffl->type) {
1299 case F_UNLCK:
1300 break;
1301
1302 case F_RDLCK:
1303 case F_WRLCK:
1304 if (ffl->start > OFFSET_MAX || ffl->end > OFFSET_MAX ||
1305 ffl->end < ffl->start)
1306 return -EIO;
1307
1308 fl->fl_start = ffl->start;
1309 fl->fl_end = ffl->end;
1310 fl->fl_pid = ffl->pid;
1311 break;
1312
1313 default:
1314 return -EIO;
1315 }
1316 fl->fl_type = ffl->type;
1317 return 0;
1318 }
1319
1320 static void fuse_lk_fill(struct fuse_req *req, struct file *file,
1321 const struct file_lock *fl, int opcode, pid_t pid,
1322 int flock)
1323 {
1324 struct inode *inode = file->f_path.dentry->d_inode;
1325 struct fuse_conn *fc = get_fuse_conn(inode);
1326 struct fuse_file *ff = file->private_data;
1327 struct fuse_lk_in *arg = &req->misc.lk_in;
1328
1329 arg->fh = ff->fh;
1330 arg->owner = fuse_lock_owner_id(fc, fl->fl_owner);
1331 arg->lk.start = fl->fl_start;
1332 arg->lk.end = fl->fl_end;
1333 arg->lk.type = fl->fl_type;
1334 arg->lk.pid = pid;
1335 if (flock)
1336 arg->lk_flags |= FUSE_LK_FLOCK;
1337 req->in.h.opcode = opcode;
1338 req->in.h.nodeid = get_node_id(inode);
1339 req->in.numargs = 1;
1340 req->in.args[0].size = sizeof(*arg);
1341 req->in.args[0].value = arg;
1342 }
1343
1344 static int fuse_getlk(struct file *file, struct file_lock *fl)
1345 {
1346 struct inode *inode = file->f_path.dentry->d_inode;
1347 struct fuse_conn *fc = get_fuse_conn(inode);
1348 struct fuse_req *req;
1349 struct fuse_lk_out outarg;
1350 int err;
1351
1352 req = fuse_get_req(fc);
1353 if (IS_ERR(req))
1354 return PTR_ERR(req);
1355
1356 fuse_lk_fill(req, file, fl, FUSE_GETLK, 0, 0);
1357 req->out.numargs = 1;
1358 req->out.args[0].size = sizeof(outarg);
1359 req->out.args[0].value = &outarg;
1360 fuse_request_send(fc, req);
1361 err = req->out.h.error;
1362 fuse_put_request(fc, req);
1363 if (!err)
1364 err = convert_fuse_file_lock(&outarg.lk, fl);
1365
1366 return err;
1367 }
1368
1369 static int fuse_setlk(struct file *file, struct file_lock *fl, int flock)
1370 {
1371 struct inode *inode = file->f_path.dentry->d_inode;
1372 struct fuse_conn *fc = get_fuse_conn(inode);
1373 struct fuse_req *req;
1374 int opcode = (fl->fl_flags & FL_SLEEP) ? FUSE_SETLKW : FUSE_SETLK;
1375 pid_t pid = fl->fl_type != F_UNLCK ? current->tgid : 0;
1376 int err;
1377
1378 if (fl->fl_lmops && fl->fl_lmops->fl_grant) {
1379 /* NLM needs asynchronous locks, which we don't support yet */
1380 return -ENOLCK;
1381 }
1382
1383 /* Unlock on close is handled by the flush method */
1384 if (fl->fl_flags & FL_CLOSE)
1385 return 0;
1386
1387 req = fuse_get_req(fc);
1388 if (IS_ERR(req))
1389 return PTR_ERR(req);
1390
1391 fuse_lk_fill(req, file, fl, opcode, pid, flock);
1392 fuse_request_send(fc, req);
1393 err = req->out.h.error;
1394 /* locking is restartable */
1395 if (err == -EINTR)
1396 err = -ERESTARTSYS;
1397 fuse_put_request(fc, req);
1398 return err;
1399 }
1400
1401 static int fuse_file_lock(struct file *file, int cmd, struct file_lock *fl)
1402 {
1403 struct inode *inode = file->f_path.dentry->d_inode;
1404 struct fuse_conn *fc = get_fuse_conn(inode);
1405 int err;
1406
1407 if (cmd == F_CANCELLK) {
1408 err = 0;
1409 } else if (cmd == F_GETLK) {
1410 if (fc->no_lock) {
1411 posix_test_lock(file, fl);
1412 err = 0;
1413 } else
1414 err = fuse_getlk(file, fl);
1415 } else {
1416 if (fc->no_lock)
1417 err = posix_lock_file(file, fl, NULL);
1418 else
1419 err = fuse_setlk(file, fl, 0);
1420 }
1421 return err;
1422 }
1423
1424 static int fuse_file_flock(struct file *file, int cmd, struct file_lock *fl)
1425 {
1426 struct inode *inode = file->f_path.dentry->d_inode;
1427 struct fuse_conn *fc = get_fuse_conn(inode);
1428 int err;
1429
1430 if (fc->no_lock) {
1431 err = flock_lock_file_wait(file, fl);
1432 } else {
1433 /* emulate flock with POSIX locks */
1434 fl->fl_owner = (fl_owner_t) file;
1435 err = fuse_setlk(file, fl, 1);
1436 }
1437
1438 return err;
1439 }
1440
1441 static sector_t fuse_bmap(struct address_space *mapping, sector_t block)
1442 {
1443 struct inode *inode = mapping->host;
1444 struct fuse_conn *fc = get_fuse_conn(inode);
1445 struct fuse_req *req;
1446 struct fuse_bmap_in inarg;
1447 struct fuse_bmap_out outarg;
1448 int err;
1449
1450 if (!inode->i_sb->s_bdev || fc->no_bmap)
1451 return 0;
1452
1453 req = fuse_get_req(fc);
1454 if (IS_ERR(req))
1455 return 0;
1456
1457 memset(&inarg, 0, sizeof(inarg));
1458 inarg.block = block;
1459 inarg.blocksize = inode->i_sb->s_blocksize;
1460 req->in.h.opcode = FUSE_BMAP;
1461 req->in.h.nodeid = get_node_id(inode);
1462 req->in.numargs = 1;
1463 req->in.args[0].size = sizeof(inarg);
1464 req->in.args[0].value = &inarg;
1465 req->out.numargs = 1;
1466 req->out.args[0].size = sizeof(outarg);
1467 req->out.args[0].value = &outarg;
1468 fuse_request_send(fc, req);
1469 err = req->out.h.error;
1470 fuse_put_request(fc, req);
1471 if (err == -ENOSYS)
1472 fc->no_bmap = 1;
1473
1474 return err ? 0 : outarg.block;
1475 }
1476
1477 static loff_t fuse_file_llseek(struct file *file, loff_t offset, int origin)
1478 {
1479 loff_t retval;
1480 struct inode *inode = file->f_path.dentry->d_inode;
1481
1482 mutex_lock(&inode->i_mutex);
1483 switch (origin) {
1484 case SEEK_END:
1485 retval = fuse_update_attributes(inode, NULL, file, NULL);
1486 if (retval)
1487 goto exit;
1488 offset += i_size_read(inode);
1489 break;
1490 case SEEK_CUR:
1491 offset += file->f_pos;
1492 }
1493 retval = -EINVAL;
1494 if (offset >= 0 && offset <= inode->i_sb->s_maxbytes) {
1495 if (offset != file->f_pos) {
1496 file->f_pos = offset;
1497 file->f_version = 0;
1498 }
1499 retval = offset;
1500 }
1501 exit:
1502 mutex_unlock(&inode->i_mutex);
1503 return retval;
1504 }
1505
1506 static int fuse_ioctl_copy_user(struct page **pages, struct iovec *iov,
1507 unsigned int nr_segs, size_t bytes, bool to_user)
1508 {
1509 struct iov_iter ii;
1510 int page_idx = 0;
1511
1512 if (!bytes)
1513 return 0;
1514
1515 iov_iter_init(&ii, iov, nr_segs, bytes, 0);
1516
1517 while (iov_iter_count(&ii)) {
1518 struct page *page = pages[page_idx++];
1519 size_t todo = min_t(size_t, PAGE_SIZE, iov_iter_count(&ii));
1520 void *kaddr, *map;
1521
1522 kaddr = map = kmap(page);
1523
1524 while (todo) {
1525 char __user *uaddr = ii.iov->iov_base + ii.iov_offset;
1526 size_t iov_len = ii.iov->iov_len - ii.iov_offset;
1527 size_t copy = min(todo, iov_len);
1528 size_t left;
1529
1530 if (!to_user)
1531 left = copy_from_user(kaddr, uaddr, copy);
1532 else
1533 left = copy_to_user(uaddr, kaddr, copy);
1534
1535 if (unlikely(left))
1536 return -EFAULT;
1537
1538 iov_iter_advance(&ii, copy);
1539 todo -= copy;
1540 kaddr += copy;
1541 }
1542
1543 kunmap(map);
1544 }
1545
1546 return 0;
1547 }
1548
1549 /*
1550 * For ioctls, there is no generic way to determine how much memory
1551 * needs to be read and/or written. Furthermore, ioctls are allowed
1552 * to dereference the passed pointer, so the parameter requires deep
1553 * copying but FUSE has no idea whatsoever about what to copy in or
1554 * out.
1555 *
1556 * This is solved by allowing FUSE server to retry ioctl with
1557 * necessary in/out iovecs. Let's assume the ioctl implementation
1558 * needs to read in the following structure.
1559 *
1560 * struct a {
1561 * char *buf;
1562 * size_t buflen;
1563 * }
1564 *
1565 * On the first callout to FUSE server, inarg->in_size and
1566 * inarg->out_size will be NULL; then, the server completes the ioctl
1567 * with FUSE_IOCTL_RETRY set in out->flags, out->in_iovs set to 1 and
1568 * the actual iov array to
1569 *
1570 * { { .iov_base = inarg.arg, .iov_len = sizeof(struct a) } }
1571 *
1572 * which tells FUSE to copy in the requested area and retry the ioctl.
1573 * On the second round, the server has access to the structure and
1574 * from that it can tell what to look for next, so on the invocation,
1575 * it sets FUSE_IOCTL_RETRY, out->in_iovs to 2 and iov array to
1576 *
1577 * { { .iov_base = inarg.arg, .iov_len = sizeof(struct a) },
1578 * { .iov_base = a.buf, .iov_len = a.buflen } }
1579 *
1580 * FUSE will copy both struct a and the pointed buffer from the
1581 * process doing the ioctl and retry ioctl with both struct a and the
1582 * buffer.
1583 *
1584 * This time, FUSE server has everything it needs and completes ioctl
1585 * without FUSE_IOCTL_RETRY which finishes the ioctl call.
1586 *
1587 * Copying data out works the same way.
1588 *
1589 * Note that if FUSE_IOCTL_UNRESTRICTED is clear, the kernel
1590 * automatically initializes in and out iovs by decoding @cmd with
1591 * _IOC_* macros and the server is not allowed to request RETRY. This
1592 * limits ioctl data transfers to well-formed ioctls and is the forced
1593 * behavior for all FUSE servers.
1594 */
1595 static long fuse_file_do_ioctl(struct file *file, unsigned int cmd,
1596 unsigned long arg, unsigned int flags)
1597 {
1598 struct inode *inode = file->f_dentry->d_inode;
1599 struct fuse_file *ff = file->private_data;
1600 struct fuse_conn *fc = get_fuse_conn(inode);
1601 struct fuse_ioctl_in inarg = {
1602 .fh = ff->fh,
1603 .cmd = cmd,
1604 .arg = arg,
1605 .flags = flags
1606 };
1607 struct fuse_ioctl_out outarg;
1608 struct fuse_req *req = NULL;
1609 struct page **pages = NULL;
1610 struct page *iov_page = NULL;
1611 struct iovec *in_iov = NULL, *out_iov = NULL;
1612 unsigned int in_iovs = 0, out_iovs = 0, num_pages = 0, max_pages;
1613 size_t in_size, out_size, transferred;
1614 int err;
1615
1616 /* assume all the iovs returned by client always fits in a page */
1617 BUILD_BUG_ON(sizeof(struct iovec) * FUSE_IOCTL_MAX_IOV > PAGE_SIZE);
1618
1619 if (!fuse_allow_task(fc, current))
1620 return -EACCES;
1621
1622 err = -EIO;
1623 if (is_bad_inode(inode))
1624 goto out;
1625
1626 err = -ENOMEM;
1627 pages = kzalloc(sizeof(pages[0]) * FUSE_MAX_PAGES_PER_REQ, GFP_KERNEL);
1628 iov_page = alloc_page(GFP_KERNEL);
1629 if (!pages || !iov_page)
1630 goto out;
1631
1632 /*
1633 * If restricted, initialize IO parameters as encoded in @cmd.
1634 * RETRY from server is not allowed.
1635 */
1636 if (!(flags & FUSE_IOCTL_UNRESTRICTED)) {
1637 struct iovec *iov = page_address(iov_page);
1638
1639 iov->iov_base = (void __user *)arg;
1640 iov->iov_len = _IOC_SIZE(cmd);
1641
1642 if (_IOC_DIR(cmd) & _IOC_WRITE) {
1643 in_iov = iov;
1644 in_iovs = 1;
1645 }
1646
1647 if (_IOC_DIR(cmd) & _IOC_READ) {
1648 out_iov = iov;
1649 out_iovs = 1;
1650 }
1651 }
1652
1653 retry:
1654 inarg.in_size = in_size = iov_length(in_iov, in_iovs);
1655 inarg.out_size = out_size = iov_length(out_iov, out_iovs);
1656
1657 /*
1658 * Out data can be used either for actual out data or iovs,
1659 * make sure there always is at least one page.
1660 */
1661 out_size = max_t(size_t, out_size, PAGE_SIZE);
1662 max_pages = DIV_ROUND_UP(max(in_size, out_size), PAGE_SIZE);
1663
1664 /* make sure there are enough buffer pages and init request with them */
1665 err = -ENOMEM;
1666 if (max_pages > FUSE_MAX_PAGES_PER_REQ)
1667 goto out;
1668 while (num_pages < max_pages) {
1669 pages[num_pages] = alloc_page(GFP_KERNEL | __GFP_HIGHMEM);
1670 if (!pages[num_pages])
1671 goto out;
1672 num_pages++;
1673 }
1674
1675 req = fuse_get_req(fc);
1676 if (IS_ERR(req)) {
1677 err = PTR_ERR(req);
1678 req = NULL;
1679 goto out;
1680 }
1681 memcpy(req->pages, pages, sizeof(req->pages[0]) * num_pages);
1682 req->num_pages = num_pages;
1683
1684 /* okay, let's send it to the client */
1685 req->in.h.opcode = FUSE_IOCTL;
1686 req->in.h.nodeid = get_node_id(inode);
1687 req->in.numargs = 1;
1688 req->in.args[0].size = sizeof(inarg);
1689 req->in.args[0].value = &inarg;
1690 if (in_size) {
1691 req->in.numargs++;
1692 req->in.args[1].size = in_size;
1693 req->in.argpages = 1;
1694
1695 err = fuse_ioctl_copy_user(pages, in_iov, in_iovs, in_size,
1696 false);
1697 if (err)
1698 goto out;
1699 }
1700
1701 req->out.numargs = 2;
1702 req->out.args[0].size = sizeof(outarg);
1703 req->out.args[0].value = &outarg;
1704 req->out.args[1].size = out_size;
1705 req->out.argpages = 1;
1706 req->out.argvar = 1;
1707
1708 fuse_request_send(fc, req);
1709 err = req->out.h.error;
1710 transferred = req->out.args[1].size;
1711 fuse_put_request(fc, req);
1712 req = NULL;
1713 if (err)
1714 goto out;
1715
1716 /* did it ask for retry? */
1717 if (outarg.flags & FUSE_IOCTL_RETRY) {
1718 char *vaddr;
1719
1720 /* no retry if in restricted mode */
1721 err = -EIO;
1722 if (!(flags & FUSE_IOCTL_UNRESTRICTED))
1723 goto out;
1724
1725 in_iovs = outarg.in_iovs;
1726 out_iovs = outarg.out_iovs;
1727
1728 /*
1729 * Make sure things are in boundary, separate checks
1730 * are to protect against overflow.
1731 */
1732 err = -ENOMEM;
1733 if (in_iovs > FUSE_IOCTL_MAX_IOV ||
1734 out_iovs > FUSE_IOCTL_MAX_IOV ||
1735 in_iovs + out_iovs > FUSE_IOCTL_MAX_IOV)
1736 goto out;
1737
1738 err = -EIO;
1739 if ((in_iovs + out_iovs) * sizeof(struct iovec) != transferred)
1740 goto out;
1741
1742 /* okay, copy in iovs and retry */
1743 vaddr = kmap_atomic(pages[0], KM_USER0);
1744 memcpy(page_address(iov_page), vaddr, transferred);
1745 kunmap_atomic(vaddr, KM_USER0);
1746
1747 in_iov = page_address(iov_page);
1748 out_iov = in_iov + in_iovs;
1749
1750 goto retry;
1751 }
1752
1753 err = -EIO;
1754 if (transferred > inarg.out_size)
1755 goto out;
1756
1757 err = fuse_ioctl_copy_user(pages, out_iov, out_iovs, transferred, true);
1758 out:
1759 if (req)
1760 fuse_put_request(fc, req);
1761 if (iov_page)
1762 __free_page(iov_page);
1763 while (num_pages)
1764 __free_page(pages[--num_pages]);
1765 kfree(pages);
1766
1767 return err ? err : outarg.result;
1768 }
1769
1770 static long fuse_file_ioctl(struct file *file, unsigned int cmd,
1771 unsigned long arg)
1772 {
1773 return fuse_file_do_ioctl(file, cmd, arg, 0);
1774 }
1775
1776 static long fuse_file_compat_ioctl(struct file *file, unsigned int cmd,
1777 unsigned long arg)
1778 {
1779 return fuse_file_do_ioctl(file, cmd, arg, FUSE_IOCTL_COMPAT);
1780 }
1781
1782 /*
1783 * All files which have been polled are linked to RB tree
1784 * fuse_conn->polled_files which is indexed by kh. Walk the tree and
1785 * find the matching one.
1786 */
1787 static struct rb_node **fuse_find_polled_node(struct fuse_conn *fc, u64 kh,
1788 struct rb_node **parent_out)
1789 {
1790 struct rb_node **link = &fc->polled_files.rb_node;
1791 struct rb_node *last = NULL;
1792
1793 while (*link) {
1794 struct fuse_file *ff;
1795
1796 last = *link;
1797 ff = rb_entry(last, struct fuse_file, polled_node);
1798
1799 if (kh < ff->kh)
1800 link = &last->rb_left;
1801 else if (kh > ff->kh)
1802 link = &last->rb_right;
1803 else
1804 return link;
1805 }
1806
1807 if (parent_out)
1808 *parent_out = last;
1809 return link;
1810 }
1811
1812 /*
1813 * The file is about to be polled. Make sure it's on the polled_files
1814 * RB tree. Note that files once added to the polled_files tree are
1815 * not removed before the file is released. This is because a file
1816 * polled once is likely to be polled again.
1817 */
1818 static void fuse_register_polled_file(struct fuse_conn *fc,
1819 struct fuse_file *ff)
1820 {
1821 spin_lock(&fc->lock);
1822 if (RB_EMPTY_NODE(&ff->polled_node)) {
1823 struct rb_node **link, *parent;
1824
1825 link = fuse_find_polled_node(fc, ff->kh, &parent);
1826 BUG_ON(*link);
1827 rb_link_node(&ff->polled_node, parent, link);
1828 rb_insert_color(&ff->polled_node, &fc->polled_files);
1829 }
1830 spin_unlock(&fc->lock);
1831 }
1832
1833 static unsigned fuse_file_poll(struct file *file, poll_table *wait)
1834 {
1835 struct inode *inode = file->f_dentry->d_inode;
1836 struct fuse_file *ff = file->private_data;
1837 struct fuse_conn *fc = get_fuse_conn(inode);
1838 struct fuse_poll_in inarg = { .fh = ff->fh, .kh = ff->kh };
1839 struct fuse_poll_out outarg;
1840 struct fuse_req *req;
1841 int err;
1842
1843 if (fc->no_poll)
1844 return DEFAULT_POLLMASK;
1845
1846 poll_wait(file, &ff->poll_wait, wait);
1847
1848 /*
1849 * Ask for notification iff there's someone waiting for it.
1850 * The client may ignore the flag and always notify.
1851 */
1852 if (waitqueue_active(&ff->poll_wait)) {
1853 inarg.flags |= FUSE_POLL_SCHEDULE_NOTIFY;
1854 fuse_register_polled_file(fc, ff);
1855 }
1856
1857 req = fuse_get_req(fc);
1858 if (IS_ERR(req))
1859 return PTR_ERR(req);
1860
1861 req->in.h.opcode = FUSE_POLL;
1862 req->in.h.nodeid = get_node_id(inode);
1863 req->in.numargs = 1;
1864 req->in.args[0].size = sizeof(inarg);
1865 req->in.args[0].value = &inarg;
1866 req->out.numargs = 1;
1867 req->out.args[0].size = sizeof(outarg);
1868 req->out.args[0].value = &outarg;
1869 fuse_request_send(fc, req);
1870 err = req->out.h.error;
1871 fuse_put_request(fc, req);
1872
1873 if (!err)
1874 return outarg.revents;
1875 if (err == -ENOSYS) {
1876 fc->no_poll = 1;
1877 return DEFAULT_POLLMASK;
1878 }
1879 return POLLERR;
1880 }
1881
1882 /*
1883 * This is called from fuse_handle_notify() on FUSE_NOTIFY_POLL and
1884 * wakes up the poll waiters.
1885 */
1886 int fuse_notify_poll_wakeup(struct fuse_conn *fc,
1887 struct fuse_notify_poll_wakeup_out *outarg)
1888 {
1889 u64 kh = outarg->kh;
1890 struct rb_node **link;
1891
1892 spin_lock(&fc->lock);
1893
1894 link = fuse_find_polled_node(fc, kh, NULL);
1895 if (*link) {
1896 struct fuse_file *ff;
1897
1898 ff = rb_entry(*link, struct fuse_file, polled_node);
1899 wake_up_interruptible_sync(&ff->poll_wait);
1900 }
1901
1902 spin_unlock(&fc->lock);
1903 return 0;
1904 }
1905
1906 static const struct file_operations fuse_file_operations = {
1907 .llseek = fuse_file_llseek,
1908 .read = do_sync_read,
1909 .aio_read = fuse_file_aio_read,
1910 .write = do_sync_write,
1911 .aio_write = fuse_file_aio_write,
1912 .mmap = fuse_file_mmap,
1913 .open = fuse_open,
1914 .flush = fuse_flush,
1915 .release = fuse_release,
1916 .fsync = fuse_fsync,
1917 .lock = fuse_file_lock,
1918 .flock = fuse_file_flock,
1919 .splice_read = generic_file_splice_read,
1920 .unlocked_ioctl = fuse_file_ioctl,
1921 .compat_ioctl = fuse_file_compat_ioctl,
1922 .poll = fuse_file_poll,
1923 };
1924
1925 static const struct file_operations fuse_direct_io_file_operations = {
1926 .llseek = fuse_file_llseek,
1927 .read = fuse_direct_read,
1928 .write = fuse_direct_write,
1929 .open = fuse_open,
1930 .flush = fuse_flush,
1931 .release = fuse_release,
1932 .fsync = fuse_fsync,
1933 .lock = fuse_file_lock,
1934 .flock = fuse_file_flock,
1935 .unlocked_ioctl = fuse_file_ioctl,
1936 .compat_ioctl = fuse_file_compat_ioctl,
1937 .poll = fuse_file_poll,
1938 /* no mmap and splice_read */
1939 };
1940
1941 static const struct address_space_operations fuse_file_aops = {
1942 .readpage = fuse_readpage,
1943 .writepage = fuse_writepage,
1944 .launder_page = fuse_launder_page,
1945 .write_begin = fuse_write_begin,
1946 .write_end = fuse_write_end,
1947 .readpages = fuse_readpages,
1948 .set_page_dirty = __set_page_dirty_nobuffers,
1949 .bmap = fuse_bmap,
1950 };
1951
1952 void fuse_init_file_inode(struct inode *inode)
1953 {
1954 inode->i_fop = &fuse_file_operations;
1955 inode->i_data.a_ops = &fuse_file_aops;
1956 }
Linux kernel - Deliverables
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