xref: /linux/fs/fuse/file.c (revision 42fda66387daa53538ae13a2c858396aaf037158)
1 /*
2   FUSE: Filesystem in Userspace
3   Copyright (C) 2001-2006  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 | O_TRUNC);
32 	req->in.h.opcode = isdir ? FUSE_OPENDIR : FUSE_OPEN;
33 	req->in.h.nodeid = get_node_id(inode);
34 	req->in.numargs = 1;
35 	req->in.args[0].size = sizeof(inarg);
36 	req->in.args[0].value = &inarg;
37 	req->out.numargs = 1;
38 	req->out.args[0].size = sizeof(*outargp);
39 	req->out.args[0].value = outargp;
40 	request_send(fc, req);
41 	err = req->out.h.error;
42 	fuse_put_request(fc, req);
43 
44 	return err;
45 }
46 
47 struct fuse_file *fuse_file_alloc(void)
48 {
49 	struct fuse_file *ff;
50 	ff = kmalloc(sizeof(struct fuse_file), GFP_KERNEL);
51 	if (ff) {
52 		ff->reserved_req = fuse_request_alloc();
53 		if (!ff->reserved_req) {
54 			kfree(ff);
55 			ff = NULL;
56 		}
57 	}
58 	return ff;
59 }
60 
61 void fuse_file_free(struct fuse_file *ff)
62 {
63 	fuse_request_free(ff->reserved_req);
64 	kfree(ff);
65 }
66 
67 void fuse_finish_open(struct inode *inode, struct file *file,
68 		      struct fuse_file *ff, struct fuse_open_out *outarg)
69 {
70 	if (outarg->open_flags & FOPEN_DIRECT_IO)
71 		file->f_op = &fuse_direct_io_file_operations;
72 	if (!(outarg->open_flags & FOPEN_KEEP_CACHE))
73 		invalidate_mapping_pages(inode->i_mapping, 0, -1);
74 	ff->fh = outarg->fh;
75 	file->private_data = ff;
76 }
77 
78 int fuse_open_common(struct inode *inode, struct file *file, int isdir)
79 {
80 	struct fuse_open_out outarg;
81 	struct fuse_file *ff;
82 	int err;
83 
84 	/* VFS checks this, but only _after_ ->open() */
85 	if (file->f_flags & O_DIRECT)
86 		return -EINVAL;
87 
88 	err = generic_file_open(inode, file);
89 	if (err)
90 		return err;
91 
92 	/* If opening the root node, no lookup has been performed on
93 	   it, so the attributes must be refreshed */
94 	if (get_node_id(inode) == FUSE_ROOT_ID) {
95 		err = fuse_do_getattr(inode);
96 		if (err)
97 		 	return err;
98 	}
99 
100 	ff = fuse_file_alloc();
101 	if (!ff)
102 		return -ENOMEM;
103 
104 	err = fuse_send_open(inode, file, isdir, &outarg);
105 	if (err)
106 		fuse_file_free(ff);
107 	else {
108 		if (isdir)
109 			outarg.open_flags &= ~FOPEN_DIRECT_IO;
110 		fuse_finish_open(inode, file, ff, &outarg);
111 	}
112 
113 	return err;
114 }
115 
116 struct fuse_req *fuse_release_fill(struct fuse_file *ff, u64 nodeid, int flags,
117 				   int opcode)
118 {
119 	struct fuse_req *req = ff->reserved_req;
120 	struct fuse_release_in *inarg = &req->misc.release_in;
121 
122 	inarg->fh = ff->fh;
123 	inarg->flags = flags;
124 	req->in.h.opcode = opcode;
125 	req->in.h.nodeid = nodeid;
126 	req->in.numargs = 1;
127 	req->in.args[0].size = sizeof(struct fuse_release_in);
128 	req->in.args[0].value = inarg;
129 	kfree(ff);
130 
131 	return req;
132 }
133 
134 int fuse_release_common(struct inode *inode, struct file *file, int isdir)
135 {
136 	struct fuse_file *ff = file->private_data;
137 	if (ff) {
138 		struct fuse_conn *fc = get_fuse_conn(inode);
139 		struct fuse_req *req;
140 
141 		req = fuse_release_fill(ff, get_node_id(inode), file->f_flags,
142 					isdir ? FUSE_RELEASEDIR : FUSE_RELEASE);
143 
144 		/* Hold vfsmount and dentry until release is finished */
145 		req->vfsmount = mntget(file->f_path.mnt);
146 		req->dentry = dget(file->f_path.dentry);
147 		request_send_background(fc, req);
148 	}
149 
150 	/* Return value is ignored by VFS */
151 	return 0;
152 }
153 
154 static int fuse_open(struct inode *inode, struct file *file)
155 {
156 	return fuse_open_common(inode, file, 0);
157 }
158 
159 static int fuse_release(struct inode *inode, struct file *file)
160 {
161 	return fuse_release_common(inode, file, 0);
162 }
163 
164 /*
165  * Scramble the ID space with XTEA, so that the value of the files_struct
166  * pointer is not exposed to userspace.
167  */
168 static u64 fuse_lock_owner_id(struct fuse_conn *fc, fl_owner_t id)
169 {
170 	u32 *k = fc->scramble_key;
171 	u64 v = (unsigned long) id;
172 	u32 v0 = v;
173 	u32 v1 = v >> 32;
174 	u32 sum = 0;
175 	int i;
176 
177 	for (i = 0; i < 32; i++) {
178 		v0 += ((v1 << 4 ^ v1 >> 5) + v1) ^ (sum + k[sum & 3]);
179 		sum += 0x9E3779B9;
180 		v1 += ((v0 << 4 ^ v0 >> 5) + v0) ^ (sum + k[sum>>11 & 3]);
181 	}
182 
183 	return (u64) v0 + ((u64) v1 << 32);
184 }
185 
186 static int fuse_flush(struct file *file, fl_owner_t id)
187 {
188 	struct inode *inode = file->f_path.dentry->d_inode;
189 	struct fuse_conn *fc = get_fuse_conn(inode);
190 	struct fuse_file *ff = file->private_data;
191 	struct fuse_req *req;
192 	struct fuse_flush_in inarg;
193 	int err;
194 
195 	if (is_bad_inode(inode))
196 		return -EIO;
197 
198 	if (fc->no_flush)
199 		return 0;
200 
201 	req = fuse_get_req_nofail(fc, file);
202 	memset(&inarg, 0, sizeof(inarg));
203 	inarg.fh = ff->fh;
204 	inarg.lock_owner = fuse_lock_owner_id(fc, id);
205 	req->in.h.opcode = FUSE_FLUSH;
206 	req->in.h.nodeid = get_node_id(inode);
207 	req->in.numargs = 1;
208 	req->in.args[0].size = sizeof(inarg);
209 	req->in.args[0].value = &inarg;
210 	req->force = 1;
211 	request_send(fc, req);
212 	err = req->out.h.error;
213 	fuse_put_request(fc, req);
214 	if (err == -ENOSYS) {
215 		fc->no_flush = 1;
216 		err = 0;
217 	}
218 	return err;
219 }
220 
221 int fuse_fsync_common(struct file *file, struct dentry *de, int datasync,
222 		      int isdir)
223 {
224 	struct inode *inode = de->d_inode;
225 	struct fuse_conn *fc = get_fuse_conn(inode);
226 	struct fuse_file *ff = file->private_data;
227 	struct fuse_req *req;
228 	struct fuse_fsync_in inarg;
229 	int err;
230 
231 	if (is_bad_inode(inode))
232 		return -EIO;
233 
234 	if ((!isdir && fc->no_fsync) || (isdir && fc->no_fsyncdir))
235 		return 0;
236 
237 	req = fuse_get_req(fc);
238 	if (IS_ERR(req))
239 		return PTR_ERR(req);
240 
241 	memset(&inarg, 0, sizeof(inarg));
242 	inarg.fh = ff->fh;
243 	inarg.fsync_flags = datasync ? 1 : 0;
244 	req->in.h.opcode = isdir ? FUSE_FSYNCDIR : FUSE_FSYNC;
245 	req->in.h.nodeid = get_node_id(inode);
246 	req->in.numargs = 1;
247 	req->in.args[0].size = sizeof(inarg);
248 	req->in.args[0].value = &inarg;
249 	request_send(fc, req);
250 	err = req->out.h.error;
251 	fuse_put_request(fc, req);
252 	if (err == -ENOSYS) {
253 		if (isdir)
254 			fc->no_fsyncdir = 1;
255 		else
256 			fc->no_fsync = 1;
257 		err = 0;
258 	}
259 	return err;
260 }
261 
262 static int fuse_fsync(struct file *file, struct dentry *de, int datasync)
263 {
264 	return fuse_fsync_common(file, de, datasync, 0);
265 }
266 
267 void fuse_read_fill(struct fuse_req *req, struct file *file,
268 		    struct inode *inode, loff_t pos, size_t count, int opcode)
269 {
270 	struct fuse_file *ff = file->private_data;
271 	struct fuse_read_in *inarg = &req->misc.read_in;
272 
273 	inarg->fh = ff->fh;
274 	inarg->offset = pos;
275 	inarg->size = count;
276 	req->in.h.opcode = opcode;
277 	req->in.h.nodeid = get_node_id(inode);
278 	req->in.numargs = 1;
279 	req->in.args[0].size = sizeof(struct fuse_read_in);
280 	req->in.args[0].value = inarg;
281 	req->out.argpages = 1;
282 	req->out.argvar = 1;
283 	req->out.numargs = 1;
284 	req->out.args[0].size = count;
285 }
286 
287 static size_t fuse_send_read(struct fuse_req *req, struct file *file,
288 			     struct inode *inode, loff_t pos, size_t count)
289 {
290 	struct fuse_conn *fc = get_fuse_conn(inode);
291 	fuse_read_fill(req, file, inode, pos, count, FUSE_READ);
292 	request_send(fc, req);
293 	return req->out.args[0].size;
294 }
295 
296 static int fuse_readpage(struct file *file, struct page *page)
297 {
298 	struct inode *inode = page->mapping->host;
299 	struct fuse_conn *fc = get_fuse_conn(inode);
300 	struct fuse_req *req;
301 	int err;
302 
303 	err = -EIO;
304 	if (is_bad_inode(inode))
305 		goto out;
306 
307 	req = fuse_get_req(fc);
308 	err = PTR_ERR(req);
309 	if (IS_ERR(req))
310 		goto out;
311 
312 	req->out.page_zeroing = 1;
313 	req->num_pages = 1;
314 	req->pages[0] = page;
315 	fuse_send_read(req, file, inode, page_offset(page), PAGE_CACHE_SIZE);
316 	err = req->out.h.error;
317 	fuse_put_request(fc, req);
318 	if (!err)
319 		SetPageUptodate(page);
320 	fuse_invalidate_attr(inode); /* atime changed */
321  out:
322 	unlock_page(page);
323 	return err;
324 }
325 
326 static void fuse_readpages_end(struct fuse_conn *fc, struct fuse_req *req)
327 {
328 	int i;
329 
330 	fuse_invalidate_attr(req->pages[0]->mapping->host); /* atime changed */
331 
332 	for (i = 0; i < req->num_pages; i++) {
333 		struct page *page = req->pages[i];
334 		if (!req->out.h.error)
335 			SetPageUptodate(page);
336 		else
337 			SetPageError(page);
338 		unlock_page(page);
339 	}
340 	fuse_put_request(fc, req);
341 }
342 
343 static void fuse_send_readpages(struct fuse_req *req, struct file *file,
344 				struct inode *inode)
345 {
346 	struct fuse_conn *fc = get_fuse_conn(inode);
347 	loff_t pos = page_offset(req->pages[0]);
348 	size_t count = req->num_pages << PAGE_CACHE_SHIFT;
349 	req->out.page_zeroing = 1;
350 	fuse_read_fill(req, file, inode, pos, count, FUSE_READ);
351 	if (fc->async_read) {
352 		get_file(file);
353 		req->file = file;
354 		req->end = fuse_readpages_end;
355 		request_send_background(fc, req);
356 	} else {
357 		request_send(fc, req);
358 		fuse_readpages_end(fc, req);
359 	}
360 }
361 
362 struct fuse_readpages_data {
363 	struct fuse_req *req;
364 	struct file *file;
365 	struct inode *inode;
366 };
367 
368 static int fuse_readpages_fill(void *_data, struct page *page)
369 {
370 	struct fuse_readpages_data *data = _data;
371 	struct fuse_req *req = data->req;
372 	struct inode *inode = data->inode;
373 	struct fuse_conn *fc = get_fuse_conn(inode);
374 
375 	if (req->num_pages &&
376 	    (req->num_pages == FUSE_MAX_PAGES_PER_REQ ||
377 	     (req->num_pages + 1) * PAGE_CACHE_SIZE > fc->max_read ||
378 	     req->pages[req->num_pages - 1]->index + 1 != page->index)) {
379 		fuse_send_readpages(req, data->file, inode);
380 		data->req = req = fuse_get_req(fc);
381 		if (IS_ERR(req)) {
382 			unlock_page(page);
383 			return PTR_ERR(req);
384 		}
385 	}
386 	req->pages[req->num_pages] = page;
387 	req->num_pages ++;
388 	return 0;
389 }
390 
391 static int fuse_readpages(struct file *file, struct address_space *mapping,
392 			  struct list_head *pages, unsigned nr_pages)
393 {
394 	struct inode *inode = mapping->host;
395 	struct fuse_conn *fc = get_fuse_conn(inode);
396 	struct fuse_readpages_data data;
397 	int err;
398 
399 	err = -EIO;
400 	if (is_bad_inode(inode))
401 		goto out;
402 
403 	data.file = file;
404 	data.inode = inode;
405 	data.req = fuse_get_req(fc);
406 	err = PTR_ERR(data.req);
407 	if (IS_ERR(data.req))
408 		goto out;
409 
410 	err = read_cache_pages(mapping, pages, fuse_readpages_fill, &data);
411 	if (!err) {
412 		if (data.req->num_pages)
413 			fuse_send_readpages(data.req, file, inode);
414 		else
415 			fuse_put_request(fc, data.req);
416 	}
417 out:
418 	return err;
419 }
420 
421 static size_t fuse_send_write(struct fuse_req *req, struct file *file,
422 			      struct inode *inode, loff_t pos, size_t count)
423 {
424 	struct fuse_conn *fc = get_fuse_conn(inode);
425 	struct fuse_file *ff = file->private_data;
426 	struct fuse_write_in inarg;
427 	struct fuse_write_out outarg;
428 
429 	memset(&inarg, 0, sizeof(struct fuse_write_in));
430 	inarg.fh = ff->fh;
431 	inarg.offset = pos;
432 	inarg.size = count;
433 	req->in.h.opcode = FUSE_WRITE;
434 	req->in.h.nodeid = get_node_id(inode);
435 	req->in.argpages = 1;
436 	req->in.numargs = 2;
437 	req->in.args[0].size = sizeof(struct fuse_write_in);
438 	req->in.args[0].value = &inarg;
439 	req->in.args[1].size = count;
440 	req->out.numargs = 1;
441 	req->out.args[0].size = sizeof(struct fuse_write_out);
442 	req->out.args[0].value = &outarg;
443 	request_send(fc, req);
444 	return outarg.size;
445 }
446 
447 static int fuse_write_begin(struct file *file, struct address_space *mapping,
448 			loff_t pos, unsigned len, unsigned flags,
449 			struct page **pagep, void **fsdata)
450 {
451 	pgoff_t index = pos >> PAGE_CACHE_SHIFT;
452 
453 	*pagep = __grab_cache_page(mapping, index);
454 	if (!*pagep)
455 		return -ENOMEM;
456 	return 0;
457 }
458 
459 static int fuse_buffered_write(struct file *file, struct inode *inode,
460 			       loff_t pos, unsigned count, struct page *page)
461 {
462 	int err;
463 	size_t nres;
464 	struct fuse_conn *fc = get_fuse_conn(inode);
465 	unsigned offset = pos & (PAGE_CACHE_SIZE - 1);
466 	struct fuse_req *req;
467 
468 	if (is_bad_inode(inode))
469 		return -EIO;
470 
471 	req = fuse_get_req(fc);
472 	if (IS_ERR(req))
473 		return PTR_ERR(req);
474 
475 	req->num_pages = 1;
476 	req->pages[0] = page;
477 	req->page_offset = offset;
478 	nres = fuse_send_write(req, file, inode, pos, count);
479 	err = req->out.h.error;
480 	fuse_put_request(fc, req);
481 	if (!err && !nres)
482 		err = -EIO;
483 	if (!err) {
484 		pos += nres;
485 		spin_lock(&fc->lock);
486 		if (pos > inode->i_size)
487 			i_size_write(inode, pos);
488 		spin_unlock(&fc->lock);
489 
490 		if (count == PAGE_CACHE_SIZE)
491 			SetPageUptodate(page);
492 	}
493 	fuse_invalidate_attr(inode);
494 	return err ? err : nres;
495 }
496 
497 static int fuse_write_end(struct file *file, struct address_space *mapping,
498 			loff_t pos, unsigned len, unsigned copied,
499 			struct page *page, void *fsdata)
500 {
501 	struct inode *inode = mapping->host;
502 	int res = 0;
503 
504 	if (copied)
505 		res = fuse_buffered_write(file, inode, pos, copied, page);
506 
507 	unlock_page(page);
508 	page_cache_release(page);
509 	return res;
510 }
511 
512 static void fuse_release_user_pages(struct fuse_req *req, int write)
513 {
514 	unsigned i;
515 
516 	for (i = 0; i < req->num_pages; i++) {
517 		struct page *page = req->pages[i];
518 		if (write)
519 			set_page_dirty_lock(page);
520 		put_page(page);
521 	}
522 }
523 
524 static int fuse_get_user_pages(struct fuse_req *req, const char __user *buf,
525 			       unsigned nbytes, int write)
526 {
527 	unsigned long user_addr = (unsigned long) buf;
528 	unsigned offset = user_addr & ~PAGE_MASK;
529 	int npages;
530 
531 	/* This doesn't work with nfsd */
532 	if (!current->mm)
533 		return -EPERM;
534 
535 	nbytes = min(nbytes, (unsigned) FUSE_MAX_PAGES_PER_REQ << PAGE_SHIFT);
536 	npages = (nbytes + offset + PAGE_SIZE - 1) >> PAGE_SHIFT;
537 	npages = min(max(npages, 1), FUSE_MAX_PAGES_PER_REQ);
538 	down_read(&current->mm->mmap_sem);
539 	npages = get_user_pages(current, current->mm, user_addr, npages, write,
540 				0, req->pages, NULL);
541 	up_read(&current->mm->mmap_sem);
542 	if (npages < 0)
543 		return npages;
544 
545 	req->num_pages = npages;
546 	req->page_offset = offset;
547 	return 0;
548 }
549 
550 static ssize_t fuse_direct_io(struct file *file, const char __user *buf,
551 			      size_t count, loff_t *ppos, int write)
552 {
553 	struct inode *inode = file->f_path.dentry->d_inode;
554 	struct fuse_conn *fc = get_fuse_conn(inode);
555 	size_t nmax = write ? fc->max_write : fc->max_read;
556 	loff_t pos = *ppos;
557 	ssize_t res = 0;
558 	struct fuse_req *req;
559 
560 	if (is_bad_inode(inode))
561 		return -EIO;
562 
563 	req = fuse_get_req(fc);
564 	if (IS_ERR(req))
565 		return PTR_ERR(req);
566 
567 	while (count) {
568 		size_t nres;
569 		size_t nbytes = min(count, nmax);
570 		int err = fuse_get_user_pages(req, buf, nbytes, !write);
571 		if (err) {
572 			res = err;
573 			break;
574 		}
575 		nbytes = (req->num_pages << PAGE_SHIFT) - req->page_offset;
576 		nbytes = min(count, nbytes);
577 		if (write)
578 			nres = fuse_send_write(req, file, inode, pos, nbytes);
579 		else
580 			nres = fuse_send_read(req, file, inode, pos, nbytes);
581 		fuse_release_user_pages(req, !write);
582 		if (req->out.h.error) {
583 			if (!res)
584 				res = req->out.h.error;
585 			break;
586 		} else if (nres > nbytes) {
587 			res = -EIO;
588 			break;
589 		}
590 		count -= nres;
591 		res += nres;
592 		pos += nres;
593 		buf += nres;
594 		if (nres != nbytes)
595 			break;
596 		if (count) {
597 			fuse_put_request(fc, req);
598 			req = fuse_get_req(fc);
599 			if (IS_ERR(req))
600 				break;
601 		}
602 	}
603 	fuse_put_request(fc, req);
604 	if (res > 0) {
605 		if (write) {
606 			spin_lock(&fc->lock);
607 			if (pos > inode->i_size)
608 				i_size_write(inode, pos);
609 			spin_unlock(&fc->lock);
610 		}
611 		*ppos = pos;
612 	}
613 	fuse_invalidate_attr(inode);
614 
615 	return res;
616 }
617 
618 static ssize_t fuse_direct_read(struct file *file, char __user *buf,
619 				     size_t count, loff_t *ppos)
620 {
621 	return fuse_direct_io(file, buf, count, ppos, 0);
622 }
623 
624 static ssize_t fuse_direct_write(struct file *file, const char __user *buf,
625 				 size_t count, loff_t *ppos)
626 {
627 	struct inode *inode = file->f_path.dentry->d_inode;
628 	ssize_t res;
629 	/* Don't allow parallel writes to the same file */
630 	mutex_lock(&inode->i_mutex);
631 	res = generic_write_checks(file, ppos, &count, 0);
632 	if (!res)
633 		res = fuse_direct_io(file, buf, count, ppos, 1);
634 	mutex_unlock(&inode->i_mutex);
635 	return res;
636 }
637 
638 static int fuse_file_mmap(struct file *file, struct vm_area_struct *vma)
639 {
640 	if ((vma->vm_flags & VM_SHARED)) {
641 		if ((vma->vm_flags & VM_WRITE))
642 			return -ENODEV;
643 		else
644 			vma->vm_flags &= ~VM_MAYWRITE;
645 	}
646 	return generic_file_mmap(file, vma);
647 }
648 
649 static int fuse_set_page_dirty(struct page *page)
650 {
651 	printk("fuse_set_page_dirty: should not happen\n");
652 	dump_stack();
653 	return 0;
654 }
655 
656 static int convert_fuse_file_lock(const struct fuse_file_lock *ffl,
657 				  struct file_lock *fl)
658 {
659 	switch (ffl->type) {
660 	case F_UNLCK:
661 		break;
662 
663 	case F_RDLCK:
664 	case F_WRLCK:
665 		if (ffl->start > OFFSET_MAX || ffl->end > OFFSET_MAX ||
666 		    ffl->end < ffl->start)
667 			return -EIO;
668 
669 		fl->fl_start = ffl->start;
670 		fl->fl_end = ffl->end;
671 		fl->fl_pid = ffl->pid;
672 		break;
673 
674 	default:
675 		return -EIO;
676 	}
677 	fl->fl_type = ffl->type;
678 	return 0;
679 }
680 
681 static void fuse_lk_fill(struct fuse_req *req, struct file *file,
682 			 const struct file_lock *fl, int opcode, pid_t pid)
683 {
684 	struct inode *inode = file->f_path.dentry->d_inode;
685 	struct fuse_conn *fc = get_fuse_conn(inode);
686 	struct fuse_file *ff = file->private_data;
687 	struct fuse_lk_in *arg = &req->misc.lk_in;
688 
689 	arg->fh = ff->fh;
690 	arg->owner = fuse_lock_owner_id(fc, fl->fl_owner);
691 	arg->lk.start = fl->fl_start;
692 	arg->lk.end = fl->fl_end;
693 	arg->lk.type = fl->fl_type;
694 	arg->lk.pid = pid;
695 	req->in.h.opcode = opcode;
696 	req->in.h.nodeid = get_node_id(inode);
697 	req->in.numargs = 1;
698 	req->in.args[0].size = sizeof(*arg);
699 	req->in.args[0].value = arg;
700 }
701 
702 static int fuse_getlk(struct file *file, struct file_lock *fl)
703 {
704 	struct inode *inode = file->f_path.dentry->d_inode;
705 	struct fuse_conn *fc = get_fuse_conn(inode);
706 	struct fuse_req *req;
707 	struct fuse_lk_out outarg;
708 	int err;
709 
710 	req = fuse_get_req(fc);
711 	if (IS_ERR(req))
712 		return PTR_ERR(req);
713 
714 	fuse_lk_fill(req, file, fl, FUSE_GETLK, 0);
715 	req->out.numargs = 1;
716 	req->out.args[0].size = sizeof(outarg);
717 	req->out.args[0].value = &outarg;
718 	request_send(fc, req);
719 	err = req->out.h.error;
720 	fuse_put_request(fc, req);
721 	if (!err)
722 		err = convert_fuse_file_lock(&outarg.lk, fl);
723 
724 	return err;
725 }
726 
727 static int fuse_setlk(struct file *file, struct file_lock *fl)
728 {
729 	struct inode *inode = file->f_path.dentry->d_inode;
730 	struct fuse_conn *fc = get_fuse_conn(inode);
731 	struct fuse_req *req;
732 	int opcode = (fl->fl_flags & FL_SLEEP) ? FUSE_SETLKW : FUSE_SETLK;
733 	pid_t pid = fl->fl_type != F_UNLCK ? current->tgid : 0;
734 	int err;
735 
736 	/* Unlock on close is handled by the flush method */
737 	if (fl->fl_flags & FL_CLOSE)
738 		return 0;
739 
740 	req = fuse_get_req(fc);
741 	if (IS_ERR(req))
742 		return PTR_ERR(req);
743 
744 	fuse_lk_fill(req, file, fl, opcode, pid);
745 	request_send(fc, req);
746 	err = req->out.h.error;
747 	/* locking is restartable */
748 	if (err == -EINTR)
749 		err = -ERESTARTSYS;
750 	fuse_put_request(fc, req);
751 	return err;
752 }
753 
754 static int fuse_file_lock(struct file *file, int cmd, struct file_lock *fl)
755 {
756 	struct inode *inode = file->f_path.dentry->d_inode;
757 	struct fuse_conn *fc = get_fuse_conn(inode);
758 	int err;
759 
760 	if (cmd == F_GETLK) {
761 		if (fc->no_lock) {
762 			posix_test_lock(file, fl);
763 			err = 0;
764 		} else
765 			err = fuse_getlk(file, fl);
766 	} else {
767 		if (fc->no_lock)
768 			err = posix_lock_file_wait(file, fl);
769 		else
770 			err = fuse_setlk(file, fl);
771 	}
772 	return err;
773 }
774 
775 static sector_t fuse_bmap(struct address_space *mapping, sector_t block)
776 {
777 	struct inode *inode = mapping->host;
778 	struct fuse_conn *fc = get_fuse_conn(inode);
779 	struct fuse_req *req;
780 	struct fuse_bmap_in inarg;
781 	struct fuse_bmap_out outarg;
782 	int err;
783 
784 	if (!inode->i_sb->s_bdev || fc->no_bmap)
785 		return 0;
786 
787 	req = fuse_get_req(fc);
788 	if (IS_ERR(req))
789 		return 0;
790 
791 	memset(&inarg, 0, sizeof(inarg));
792 	inarg.block = block;
793 	inarg.blocksize = inode->i_sb->s_blocksize;
794 	req->in.h.opcode = FUSE_BMAP;
795 	req->in.h.nodeid = get_node_id(inode);
796 	req->in.numargs = 1;
797 	req->in.args[0].size = sizeof(inarg);
798 	req->in.args[0].value = &inarg;
799 	req->out.numargs = 1;
800 	req->out.args[0].size = sizeof(outarg);
801 	req->out.args[0].value = &outarg;
802 	request_send(fc, req);
803 	err = req->out.h.error;
804 	fuse_put_request(fc, req);
805 	if (err == -ENOSYS)
806 		fc->no_bmap = 1;
807 
808 	return err ? 0 : outarg.block;
809 }
810 
811 static const struct file_operations fuse_file_operations = {
812 	.llseek		= generic_file_llseek,
813 	.read		= do_sync_read,
814 	.aio_read	= generic_file_aio_read,
815 	.write		= do_sync_write,
816 	.aio_write	= generic_file_aio_write,
817 	.mmap		= fuse_file_mmap,
818 	.open		= fuse_open,
819 	.flush		= fuse_flush,
820 	.release	= fuse_release,
821 	.fsync		= fuse_fsync,
822 	.lock		= fuse_file_lock,
823 	.splice_read	= generic_file_splice_read,
824 };
825 
826 static const struct file_operations fuse_direct_io_file_operations = {
827 	.llseek		= generic_file_llseek,
828 	.read		= fuse_direct_read,
829 	.write		= fuse_direct_write,
830 	.open		= fuse_open,
831 	.flush		= fuse_flush,
832 	.release	= fuse_release,
833 	.fsync		= fuse_fsync,
834 	.lock		= fuse_file_lock,
835 	/* no mmap and splice_read */
836 };
837 
838 static const struct address_space_operations fuse_file_aops  = {
839 	.readpage	= fuse_readpage,
840 	.write_begin	= fuse_write_begin,
841 	.write_end	= fuse_write_end,
842 	.readpages	= fuse_readpages,
843 	.set_page_dirty	= fuse_set_page_dirty,
844 	.bmap		= fuse_bmap,
845 };
846 
847 void fuse_init_file_inode(struct inode *inode)
848 {
849 	inode->i_fop = &fuse_file_operations;
850 	inode->i_data.a_ops = &fuse_file_aops;
851 }
852