Merge git://git.kernel.org/pub/scm/linux/kernel/git/bart/ide-2.6
[linux-2.6] / fs / fuse / file.c
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);
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         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(void)
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                         ff = NULL;
58                 } else {
59                         INIT_LIST_HEAD(&ff->write_entry);
60                         atomic_set(&ff->count, 0);
61                 }
62         }
63         return ff;
64 }
65
66 void fuse_file_free(struct fuse_file *ff)
67 {
68         fuse_request_free(ff->reserved_req);
69         kfree(ff);
70 }
71
72 static struct fuse_file *fuse_file_get(struct fuse_file *ff)
73 {
74         atomic_inc(&ff->count);
75         return ff;
76 }
77
78 static void fuse_release_end(struct fuse_conn *fc, struct fuse_req *req)
79 {
80         dput(req->misc.release.dentry);
81         mntput(req->misc.release.vfsmount);
82         fuse_put_request(fc, req);
83 }
84
85 static void fuse_file_put(struct fuse_file *ff)
86 {
87         if (atomic_dec_and_test(&ff->count)) {
88                 struct fuse_req *req = ff->reserved_req;
89                 struct inode *inode = req->misc.release.dentry->d_inode;
90                 struct fuse_conn *fc = get_fuse_conn(inode);
91                 req->end = fuse_release_end;
92                 request_send_background(fc, req);
93                 kfree(ff);
94         }
95 }
96
97 void fuse_finish_open(struct inode *inode, struct file *file,
98                       struct fuse_file *ff, struct fuse_open_out *outarg)
99 {
100         if (outarg->open_flags & FOPEN_DIRECT_IO)
101                 file->f_op = &fuse_direct_io_file_operations;
102         if (!(outarg->open_flags & FOPEN_KEEP_CACHE))
103                 invalidate_inode_pages2(inode->i_mapping);
104         ff->fh = outarg->fh;
105         file->private_data = fuse_file_get(ff);
106 }
107
108 int fuse_open_common(struct inode *inode, struct file *file, int isdir)
109 {
110         struct fuse_open_out outarg;
111         struct fuse_file *ff;
112         int err;
113
114         /* VFS checks this, but only _after_ ->open() */
115         if (file->f_flags & O_DIRECT)
116                 return -EINVAL;
117
118         err = generic_file_open(inode, file);
119         if (err)
120                 return err;
121
122         ff = fuse_file_alloc();
123         if (!ff)
124                 return -ENOMEM;
125
126         err = fuse_send_open(inode, file, isdir, &outarg);
127         if (err)
128                 fuse_file_free(ff);
129         else {
130                 if (isdir)
131                         outarg.open_flags &= ~FOPEN_DIRECT_IO;
132                 fuse_finish_open(inode, file, ff, &outarg);
133         }
134
135         return err;
136 }
137
138 void fuse_release_fill(struct fuse_file *ff, u64 nodeid, int flags, int opcode)
139 {
140         struct fuse_req *req = ff->reserved_req;
141         struct fuse_release_in *inarg = &req->misc.release.in;
142
143         inarg->fh = ff->fh;
144         inarg->flags = flags;
145         req->in.h.opcode = opcode;
146         req->in.h.nodeid = nodeid;
147         req->in.numargs = 1;
148         req->in.args[0].size = sizeof(struct fuse_release_in);
149         req->in.args[0].value = inarg;
150 }
151
152 int fuse_release_common(struct inode *inode, struct file *file, int isdir)
153 {
154         struct fuse_file *ff = file->private_data;
155         if (ff) {
156                 struct fuse_conn *fc = get_fuse_conn(inode);
157                 struct fuse_req *req = ff->reserved_req;
158
159                 fuse_release_fill(ff, get_node_id(inode), file->f_flags,
160                                   isdir ? FUSE_RELEASEDIR : FUSE_RELEASE);
161
162                 /* Hold vfsmount and dentry until release is finished */
163                 req->misc.release.vfsmount = mntget(file->f_path.mnt);
164                 req->misc.release.dentry = dget(file->f_path.dentry);
165
166                 spin_lock(&fc->lock);
167                 list_del(&ff->write_entry);
168                 spin_unlock(&fc->lock);
169                 /*
170                  * Normally this will send the RELEASE request,
171                  * however if some asynchronous READ or WRITE requests
172                  * are outstanding, the sending will be delayed
173                  */
174                 fuse_file_put(ff);
175         }
176
177         /* Return value is ignored by VFS */
178         return 0;
179 }
180
181 static int fuse_open(struct inode *inode, struct file *file)
182 {
183         return fuse_open_common(inode, file, 0);
184 }
185
186 static int fuse_release(struct inode *inode, struct file *file)
187 {
188         return fuse_release_common(inode, file, 0);
189 }
190
191 /*
192  * Scramble the ID space with XTEA, so that the value of the files_struct
193  * pointer is not exposed to userspace.
194  */
195 u64 fuse_lock_owner_id(struct fuse_conn *fc, fl_owner_t id)
196 {
197         u32 *k = fc->scramble_key;
198         u64 v = (unsigned long) id;
199         u32 v0 = v;
200         u32 v1 = v >> 32;
201         u32 sum = 0;
202         int i;
203
204         for (i = 0; i < 32; i++) {
205                 v0 += ((v1 << 4 ^ v1 >> 5) + v1) ^ (sum + k[sum & 3]);
206                 sum += 0x9E3779B9;
207                 v1 += ((v0 << 4 ^ v0 >> 5) + v0) ^ (sum + k[sum>>11 & 3]);
208         }
209
210         return (u64) v0 + ((u64) v1 << 32);
211 }
212
213 /*
214  * Check if page is under writeback
215  *
216  * This is currently done by walking the list of writepage requests
217  * for the inode, which can be pretty inefficient.
218  */
219 static bool fuse_page_is_writeback(struct inode *inode, pgoff_t index)
220 {
221         struct fuse_conn *fc = get_fuse_conn(inode);
222         struct fuse_inode *fi = get_fuse_inode(inode);
223         struct fuse_req *req;
224         bool found = false;
225
226         spin_lock(&fc->lock);
227         list_for_each_entry(req, &fi->writepages, writepages_entry) {
228                 pgoff_t curr_index;
229
230                 BUG_ON(req->inode != inode);
231                 curr_index = req->misc.write.in.offset >> PAGE_CACHE_SHIFT;
232                 if (curr_index == index) {
233                         found = true;
234                         break;
235                 }
236         }
237         spin_unlock(&fc->lock);
238
239         return found;
240 }
241
242 /*
243  * Wait for page writeback to be completed.
244  *
245  * Since fuse doesn't rely on the VM writeback tracking, this has to
246  * use some other means.
247  */
248 static int fuse_wait_on_page_writeback(struct inode *inode, pgoff_t index)
249 {
250         struct fuse_inode *fi = get_fuse_inode(inode);
251
252         wait_event(fi->page_waitq, !fuse_page_is_writeback(inode, index));
253         return 0;
254 }
255
256 static int fuse_flush(struct file *file, fl_owner_t id)
257 {
258         struct inode *inode = file->f_path.dentry->d_inode;
259         struct fuse_conn *fc = get_fuse_conn(inode);
260         struct fuse_file *ff = file->private_data;
261         struct fuse_req *req;
262         struct fuse_flush_in inarg;
263         int err;
264
265         if (is_bad_inode(inode))
266                 return -EIO;
267
268         if (fc->no_flush)
269                 return 0;
270
271         req = fuse_get_req_nofail(fc, file);
272         memset(&inarg, 0, sizeof(inarg));
273         inarg.fh = ff->fh;
274         inarg.lock_owner = fuse_lock_owner_id(fc, id);
275         req->in.h.opcode = FUSE_FLUSH;
276         req->in.h.nodeid = get_node_id(inode);
277         req->in.numargs = 1;
278         req->in.args[0].size = sizeof(inarg);
279         req->in.args[0].value = &inarg;
280         req->force = 1;
281         request_send(fc, req);
282         err = req->out.h.error;
283         fuse_put_request(fc, req);
284         if (err == -ENOSYS) {
285                 fc->no_flush = 1;
286                 err = 0;
287         }
288         return err;
289 }
290
291 /*
292  * Wait for all pending writepages on the inode to finish.
293  *
294  * This is currently done by blocking further writes with FUSE_NOWRITE
295  * and waiting for all sent writes to complete.
296  *
297  * This must be called under i_mutex, otherwise the FUSE_NOWRITE usage
298  * could conflict with truncation.
299  */
300 static void fuse_sync_writes(struct inode *inode)
301 {
302         fuse_set_nowrite(inode);
303         fuse_release_nowrite(inode);
304 }
305
306 int fuse_fsync_common(struct file *file, struct dentry *de, int datasync,
307                       int isdir)
308 {
309         struct inode *inode = de->d_inode;
310         struct fuse_conn *fc = get_fuse_conn(inode);
311         struct fuse_file *ff = file->private_data;
312         struct fuse_req *req;
313         struct fuse_fsync_in inarg;
314         int err;
315
316         if (is_bad_inode(inode))
317                 return -EIO;
318
319         if ((!isdir && fc->no_fsync) || (isdir && fc->no_fsyncdir))
320                 return 0;
321
322         /*
323          * Start writeback against all dirty pages of the inode, then
324          * wait for all outstanding writes, before sending the FSYNC
325          * request.
326          */
327         err = write_inode_now(inode, 0);
328         if (err)
329                 return err;
330
331         fuse_sync_writes(inode);
332
333         req = fuse_get_req(fc);
334         if (IS_ERR(req))
335                 return PTR_ERR(req);
336
337         memset(&inarg, 0, sizeof(inarg));
338         inarg.fh = ff->fh;
339         inarg.fsync_flags = datasync ? 1 : 0;
340         req->in.h.opcode = isdir ? FUSE_FSYNCDIR : FUSE_FSYNC;
341         req->in.h.nodeid = get_node_id(inode);
342         req->in.numargs = 1;
343         req->in.args[0].size = sizeof(inarg);
344         req->in.args[0].value = &inarg;
345         request_send(fc, req);
346         err = req->out.h.error;
347         fuse_put_request(fc, req);
348         if (err == -ENOSYS) {
349                 if (isdir)
350                         fc->no_fsyncdir = 1;
351                 else
352                         fc->no_fsync = 1;
353                 err = 0;
354         }
355         return err;
356 }
357
358 static int fuse_fsync(struct file *file, struct dentry *de, int datasync)
359 {
360         return fuse_fsync_common(file, de, datasync, 0);
361 }
362
363 void fuse_read_fill(struct fuse_req *req, struct file *file,
364                     struct inode *inode, loff_t pos, size_t count, int opcode)
365 {
366         struct fuse_read_in *inarg = &req->misc.read.in;
367         struct fuse_file *ff = file->private_data;
368
369         inarg->fh = ff->fh;
370         inarg->offset = pos;
371         inarg->size = count;
372         inarg->flags = file->f_flags;
373         req->in.h.opcode = opcode;
374         req->in.h.nodeid = get_node_id(inode);
375         req->in.numargs = 1;
376         req->in.args[0].size = sizeof(struct fuse_read_in);
377         req->in.args[0].value = inarg;
378         req->out.argpages = 1;
379         req->out.argvar = 1;
380         req->out.numargs = 1;
381         req->out.args[0].size = count;
382 }
383
384 static size_t fuse_send_read(struct fuse_req *req, struct file *file,
385                              struct inode *inode, loff_t pos, size_t count,
386                              fl_owner_t owner)
387 {
388         struct fuse_conn *fc = get_fuse_conn(inode);
389
390         fuse_read_fill(req, file, inode, pos, count, FUSE_READ);
391         if (owner != NULL) {
392                 struct fuse_read_in *inarg = &req->misc.read.in;
393
394                 inarg->read_flags |= FUSE_READ_LOCKOWNER;
395                 inarg->lock_owner = fuse_lock_owner_id(fc, owner);
396         }
397         request_send(fc, req);
398         return req->out.args[0].size;
399 }
400
401 static void fuse_read_update_size(struct inode *inode, loff_t size,
402                                   u64 attr_ver)
403 {
404         struct fuse_conn *fc = get_fuse_conn(inode);
405         struct fuse_inode *fi = get_fuse_inode(inode);
406
407         spin_lock(&fc->lock);
408         if (attr_ver == fi->attr_version && size < inode->i_size) {
409                 fi->attr_version = ++fc->attr_version;
410                 i_size_write(inode, size);
411         }
412         spin_unlock(&fc->lock);
413 }
414
415 static int fuse_readpage(struct file *file, struct page *page)
416 {
417         struct inode *inode = page->mapping->host;
418         struct fuse_conn *fc = get_fuse_conn(inode);
419         struct fuse_req *req;
420         size_t num_read;
421         loff_t pos = page_offset(page);
422         size_t count = PAGE_CACHE_SIZE;
423         u64 attr_ver;
424         int err;
425
426         err = -EIO;
427         if (is_bad_inode(inode))
428                 goto out;
429
430         /*
431          * Page writeback can extend beyond the liftime of the
432          * page-cache page, so make sure we read a properly synced
433          * page.
434          */
435         fuse_wait_on_page_writeback(inode, page->index);
436
437         req = fuse_get_req(fc);
438         err = PTR_ERR(req);
439         if (IS_ERR(req))
440                 goto out;
441
442         attr_ver = fuse_get_attr_version(fc);
443
444         req->out.page_zeroing = 1;
445         req->num_pages = 1;
446         req->pages[0] = page;
447         num_read = fuse_send_read(req, file, inode, pos, count, NULL);
448         err = req->out.h.error;
449         fuse_put_request(fc, req);
450
451         if (!err) {
452                 /*
453                  * Short read means EOF.  If file size is larger, truncate it
454                  */
455                 if (num_read < count)
456                         fuse_read_update_size(inode, pos + num_read, attr_ver);
457
458                 SetPageUptodate(page);
459         }
460
461         fuse_invalidate_attr(inode); /* atime changed */
462  out:
463         unlock_page(page);
464         return err;
465 }
466
467 static void fuse_readpages_end(struct fuse_conn *fc, struct fuse_req *req)
468 {
469         int i;
470         size_t count = req->misc.read.in.size;
471         size_t num_read = req->out.args[0].size;
472         struct inode *inode = req->pages[0]->mapping->host;
473
474         /*
475          * Short read means EOF.  If file size is larger, truncate it
476          */
477         if (!req->out.h.error && num_read < count) {
478                 loff_t pos = page_offset(req->pages[0]) + num_read;
479                 fuse_read_update_size(inode, pos, req->misc.read.attr_ver);
480         }
481
482         fuse_invalidate_attr(inode); /* atime changed */
483
484         for (i = 0; i < req->num_pages; i++) {
485                 struct page *page = req->pages[i];
486                 if (!req->out.h.error)
487                         SetPageUptodate(page);
488                 else
489                         SetPageError(page);
490                 unlock_page(page);
491         }
492         if (req->ff)
493                 fuse_file_put(req->ff);
494         fuse_put_request(fc, req);
495 }
496
497 static void fuse_send_readpages(struct fuse_req *req, struct file *file,
498                                 struct inode *inode)
499 {
500         struct fuse_conn *fc = get_fuse_conn(inode);
501         loff_t pos = page_offset(req->pages[0]);
502         size_t count = req->num_pages << PAGE_CACHE_SHIFT;
503         req->out.page_zeroing = 1;
504         fuse_read_fill(req, file, inode, pos, count, FUSE_READ);
505         req->misc.read.attr_ver = fuse_get_attr_version(fc);
506         if (fc->async_read) {
507                 struct fuse_file *ff = file->private_data;
508                 req->ff = fuse_file_get(ff);
509                 req->end = fuse_readpages_end;
510                 request_send_background(fc, req);
511         } else {
512                 request_send(fc, req);
513                 fuse_readpages_end(fc, req);
514         }
515 }
516
517 struct fuse_fill_data {
518         struct fuse_req *req;
519         struct file *file;
520         struct inode *inode;
521 };
522
523 static int fuse_readpages_fill(void *_data, struct page *page)
524 {
525         struct fuse_fill_data *data = _data;
526         struct fuse_req *req = data->req;
527         struct inode *inode = data->inode;
528         struct fuse_conn *fc = get_fuse_conn(inode);
529
530         fuse_wait_on_page_writeback(inode, page->index);
531
532         if (req->num_pages &&
533             (req->num_pages == FUSE_MAX_PAGES_PER_REQ ||
534              (req->num_pages + 1) * PAGE_CACHE_SIZE > fc->max_read ||
535              req->pages[req->num_pages - 1]->index + 1 != page->index)) {
536                 fuse_send_readpages(req, data->file, inode);
537                 data->req = req = fuse_get_req(fc);
538                 if (IS_ERR(req)) {
539                         unlock_page(page);
540                         return PTR_ERR(req);
541                 }
542         }
543         req->pages[req->num_pages] = page;
544         req->num_pages ++;
545         return 0;
546 }
547
548 static int fuse_readpages(struct file *file, struct address_space *mapping,
549                           struct list_head *pages, unsigned nr_pages)
550 {
551         struct inode *inode = mapping->host;
552         struct fuse_conn *fc = get_fuse_conn(inode);
553         struct fuse_fill_data data;
554         int err;
555
556         err = -EIO;
557         if (is_bad_inode(inode))
558                 goto out;
559
560         data.file = file;
561         data.inode = inode;
562         data.req = fuse_get_req(fc);
563         err = PTR_ERR(data.req);
564         if (IS_ERR(data.req))
565                 goto out;
566
567         err = read_cache_pages(mapping, pages, fuse_readpages_fill, &data);
568         if (!err) {
569                 if (data.req->num_pages)
570                         fuse_send_readpages(data.req, file, inode);
571                 else
572                         fuse_put_request(fc, data.req);
573         }
574 out:
575         return err;
576 }
577
578 static ssize_t fuse_file_aio_read(struct kiocb *iocb, const struct iovec *iov,
579                                   unsigned long nr_segs, loff_t pos)
580 {
581         struct inode *inode = iocb->ki_filp->f_mapping->host;
582
583         if (pos + iov_length(iov, nr_segs) > i_size_read(inode)) {
584                 int err;
585                 /*
586                  * If trying to read past EOF, make sure the i_size
587                  * attribute is up-to-date.
588                  */
589                 err = fuse_update_attributes(inode, NULL, iocb->ki_filp, NULL);
590                 if (err)
591                         return err;
592         }
593
594         return generic_file_aio_read(iocb, iov, nr_segs, pos);
595 }
596
597 static void fuse_write_fill(struct fuse_req *req, struct file *file,
598                             struct fuse_file *ff, struct inode *inode,
599                             loff_t pos, size_t count, int writepage)
600 {
601         struct fuse_conn *fc = get_fuse_conn(inode);
602         struct fuse_write_in *inarg = &req->misc.write.in;
603         struct fuse_write_out *outarg = &req->misc.write.out;
604
605         memset(inarg, 0, sizeof(struct fuse_write_in));
606         inarg->fh = ff->fh;
607         inarg->offset = pos;
608         inarg->size = count;
609         inarg->write_flags = writepage ? FUSE_WRITE_CACHE : 0;
610         inarg->flags = file ? file->f_flags : 0;
611         req->in.h.opcode = FUSE_WRITE;
612         req->in.h.nodeid = get_node_id(inode);
613         req->in.argpages = 1;
614         req->in.numargs = 2;
615         if (fc->minor < 9)
616                 req->in.args[0].size = FUSE_COMPAT_WRITE_IN_SIZE;
617         else
618                 req->in.args[0].size = sizeof(struct fuse_write_in);
619         req->in.args[0].value = inarg;
620         req->in.args[1].size = count;
621         req->out.numargs = 1;
622         req->out.args[0].size = sizeof(struct fuse_write_out);
623         req->out.args[0].value = outarg;
624 }
625
626 static size_t fuse_send_write(struct fuse_req *req, struct file *file,
627                               struct inode *inode, loff_t pos, size_t count,
628                               fl_owner_t owner)
629 {
630         struct fuse_conn *fc = get_fuse_conn(inode);
631         fuse_write_fill(req, file, file->private_data, inode, pos, count, 0);
632         if (owner != NULL) {
633                 struct fuse_write_in *inarg = &req->misc.write.in;
634                 inarg->write_flags |= FUSE_WRITE_LOCKOWNER;
635                 inarg->lock_owner = fuse_lock_owner_id(fc, owner);
636         }
637         request_send(fc, req);
638         return req->misc.write.out.size;
639 }
640
641 static int fuse_write_begin(struct file *file, struct address_space *mapping,
642                         loff_t pos, unsigned len, unsigned flags,
643                         struct page **pagep, void **fsdata)
644 {
645         pgoff_t index = pos >> PAGE_CACHE_SHIFT;
646
647         *pagep = __grab_cache_page(mapping, index);
648         if (!*pagep)
649                 return -ENOMEM;
650         return 0;
651 }
652
653 static void fuse_write_update_size(struct inode *inode, loff_t pos)
654 {
655         struct fuse_conn *fc = get_fuse_conn(inode);
656         struct fuse_inode *fi = get_fuse_inode(inode);
657
658         spin_lock(&fc->lock);
659         fi->attr_version = ++fc->attr_version;
660         if (pos > inode->i_size)
661                 i_size_write(inode, pos);
662         spin_unlock(&fc->lock);
663 }
664
665 static int fuse_buffered_write(struct file *file, struct inode *inode,
666                                loff_t pos, unsigned count, struct page *page)
667 {
668         int err;
669         size_t nres;
670         struct fuse_conn *fc = get_fuse_conn(inode);
671         unsigned offset = pos & (PAGE_CACHE_SIZE - 1);
672         struct fuse_req *req;
673
674         if (is_bad_inode(inode))
675                 return -EIO;
676
677         /*
678          * Make sure writepages on the same page are not mixed up with
679          * plain writes.
680          */
681         fuse_wait_on_page_writeback(inode, page->index);
682
683         req = fuse_get_req(fc);
684         if (IS_ERR(req))
685                 return PTR_ERR(req);
686
687         req->num_pages = 1;
688         req->pages[0] = page;
689         req->page_offset = offset;
690         nres = fuse_send_write(req, file, inode, pos, count, NULL);
691         err = req->out.h.error;
692         fuse_put_request(fc, req);
693         if (!err && !nres)
694                 err = -EIO;
695         if (!err) {
696                 pos += nres;
697                 fuse_write_update_size(inode, pos);
698                 if (count == PAGE_CACHE_SIZE)
699                         SetPageUptodate(page);
700         }
701         fuse_invalidate_attr(inode);
702         return err ? err : nres;
703 }
704
705 static int fuse_write_end(struct file *file, struct address_space *mapping,
706                         loff_t pos, unsigned len, unsigned copied,
707                         struct page *page, void *fsdata)
708 {
709         struct inode *inode = mapping->host;
710         int res = 0;
711
712         if (copied)
713                 res = fuse_buffered_write(file, inode, pos, copied, page);
714
715         unlock_page(page);
716         page_cache_release(page);
717         return res;
718 }
719
720 static size_t fuse_send_write_pages(struct fuse_req *req, struct file *file,
721                                     struct inode *inode, loff_t pos,
722                                     size_t count)
723 {
724         size_t res;
725         unsigned offset;
726         unsigned i;
727
728         for (i = 0; i < req->num_pages; i++)
729                 fuse_wait_on_page_writeback(inode, req->pages[i]->index);
730
731         res = fuse_send_write(req, file, inode, pos, count, NULL);
732
733         offset = req->page_offset;
734         count = res;
735         for (i = 0; i < req->num_pages; i++) {
736                 struct page *page = req->pages[i];
737
738                 if (!req->out.h.error && !offset && count >= PAGE_CACHE_SIZE)
739                         SetPageUptodate(page);
740
741                 if (count > PAGE_CACHE_SIZE - offset)
742                         count -= PAGE_CACHE_SIZE - offset;
743                 else
744                         count = 0;
745                 offset = 0;
746
747                 unlock_page(page);
748                 page_cache_release(page);
749         }
750
751         return res;
752 }
753
754 static ssize_t fuse_fill_write_pages(struct fuse_req *req,
755                                struct address_space *mapping,
756                                struct iov_iter *ii, loff_t pos)
757 {
758         struct fuse_conn *fc = get_fuse_conn(mapping->host);
759         unsigned offset = pos & (PAGE_CACHE_SIZE - 1);
760         size_t count = 0;
761         int err;
762
763         req->page_offset = offset;
764
765         do {
766                 size_t tmp;
767                 struct page *page;
768                 pgoff_t index = pos >> PAGE_CACHE_SHIFT;
769                 size_t bytes = min_t(size_t, PAGE_CACHE_SIZE - offset,
770                                      iov_iter_count(ii));
771
772                 bytes = min_t(size_t, bytes, fc->max_write - count);
773
774  again:
775                 err = -EFAULT;
776                 if (iov_iter_fault_in_readable(ii, bytes))
777                         break;
778
779                 err = -ENOMEM;
780                 page = __grab_cache_page(mapping, index);
781                 if (!page)
782                         break;
783
784                 pagefault_disable();
785                 tmp = iov_iter_copy_from_user_atomic(page, ii, offset, bytes);
786                 pagefault_enable();
787                 flush_dcache_page(page);
788
789                 if (!tmp) {
790                         unlock_page(page);
791                         page_cache_release(page);
792                         bytes = min(bytes, iov_iter_single_seg_count(ii));
793                         goto again;
794                 }
795
796                 err = 0;
797                 req->pages[req->num_pages] = page;
798                 req->num_pages++;
799
800                 iov_iter_advance(ii, tmp);
801                 count += tmp;
802                 pos += tmp;
803                 offset += tmp;
804                 if (offset == PAGE_CACHE_SIZE)
805                         offset = 0;
806
807         } while (iov_iter_count(ii) && count < fc->max_write &&
808                  req->num_pages < FUSE_MAX_PAGES_PER_REQ && offset == 0);
809
810         return count > 0 ? count : err;
811 }
812
813 static ssize_t fuse_perform_write(struct file *file,
814                                   struct address_space *mapping,
815                                   struct iov_iter *ii, loff_t pos)
816 {
817         struct inode *inode = mapping->host;
818         struct fuse_conn *fc = get_fuse_conn(inode);
819         int err = 0;
820         ssize_t res = 0;
821
822         if (is_bad_inode(inode))
823                 return -EIO;
824
825         do {
826                 struct fuse_req *req;
827                 ssize_t count;
828
829                 req = fuse_get_req(fc);
830                 if (IS_ERR(req)) {
831                         err = PTR_ERR(req);
832                         break;
833                 }
834
835                 count = fuse_fill_write_pages(req, mapping, ii, pos);
836                 if (count <= 0) {
837                         err = count;
838                 } else {
839                         size_t num_written;
840
841                         num_written = fuse_send_write_pages(req, file, inode,
842                                                             pos, count);
843                         err = req->out.h.error;
844                         if (!err) {
845                                 res += num_written;
846                                 pos += num_written;
847
848                                 /* break out of the loop on short write */
849                                 if (num_written != count)
850                                         err = -EIO;
851                         }
852                 }
853                 fuse_put_request(fc, req);
854         } while (!err && iov_iter_count(ii));
855
856         if (res > 0)
857                 fuse_write_update_size(inode, pos);
858
859         fuse_invalidate_attr(inode);
860
861         return res > 0 ? res : err;
862 }
863
864 static ssize_t fuse_file_aio_write(struct kiocb *iocb, const struct iovec *iov,
865                                    unsigned long nr_segs, loff_t pos)
866 {
867         struct file *file = iocb->ki_filp;
868         struct address_space *mapping = file->f_mapping;
869         size_t count = 0;
870         ssize_t written = 0;
871         struct inode *inode = mapping->host;
872         ssize_t err;
873         struct iov_iter i;
874
875         WARN_ON(iocb->ki_pos != pos);
876
877         err = generic_segment_checks(iov, &nr_segs, &count, VERIFY_READ);
878         if (err)
879                 return err;
880
881         mutex_lock(&inode->i_mutex);
882         vfs_check_frozen(inode->i_sb, SB_FREEZE_WRITE);
883
884         /* We can write back this queue in page reclaim */
885         current->backing_dev_info = mapping->backing_dev_info;
886
887         err = generic_write_checks(file, &pos, &count, S_ISBLK(inode->i_mode));
888         if (err)
889                 goto out;
890
891         if (count == 0)
892                 goto out;
893
894         err = remove_suid(file->f_path.dentry);
895         if (err)
896                 goto out;
897
898         file_update_time(file);
899
900         iov_iter_init(&i, iov, nr_segs, count, 0);
901         written = fuse_perform_write(file, mapping, &i, pos);
902         if (written >= 0)
903                 iocb->ki_pos = pos + written;
904
905 out:
906         current->backing_dev_info = NULL;
907         mutex_unlock(&inode->i_mutex);
908
909         return written ? written : err;
910 }
911
912 static void fuse_release_user_pages(struct fuse_req *req, int write)
913 {
914         unsigned i;
915
916         for (i = 0; i < req->num_pages; i++) {
917                 struct page *page = req->pages[i];
918                 if (write)
919                         set_page_dirty_lock(page);
920                 put_page(page);
921         }
922 }
923
924 static int fuse_get_user_pages(struct fuse_req *req, const char __user *buf,
925                                unsigned nbytes, int write)
926 {
927         unsigned long user_addr = (unsigned long) buf;
928         unsigned offset = user_addr & ~PAGE_MASK;
929         int npages;
930
931         /* This doesn't work with nfsd */
932         if (!current->mm)
933                 return -EPERM;
934
935         nbytes = min(nbytes, (unsigned) FUSE_MAX_PAGES_PER_REQ << PAGE_SHIFT);
936         npages = (nbytes + offset + PAGE_SIZE - 1) >> PAGE_SHIFT;
937         npages = clamp(npages, 1, FUSE_MAX_PAGES_PER_REQ);
938         down_read(&current->mm->mmap_sem);
939         npages = get_user_pages(current, current->mm, user_addr, npages, write,
940                                 0, req->pages, NULL);
941         up_read(&current->mm->mmap_sem);
942         if (npages < 0)
943                 return npages;
944
945         req->num_pages = npages;
946         req->page_offset = offset;
947         return 0;
948 }
949
950 static ssize_t fuse_direct_io(struct file *file, const char __user *buf,
951                               size_t count, loff_t *ppos, int write)
952 {
953         struct inode *inode = file->f_path.dentry->d_inode;
954         struct fuse_conn *fc = get_fuse_conn(inode);
955         size_t nmax = write ? fc->max_write : fc->max_read;
956         loff_t pos = *ppos;
957         ssize_t res = 0;
958         struct fuse_req *req;
959
960         if (is_bad_inode(inode))
961                 return -EIO;
962
963         req = fuse_get_req(fc);
964         if (IS_ERR(req))
965                 return PTR_ERR(req);
966
967         while (count) {
968                 size_t nres;
969                 size_t nbytes_limit = min(count, nmax);
970                 size_t nbytes;
971                 int err = fuse_get_user_pages(req, buf, nbytes_limit, !write);
972                 if (err) {
973                         res = err;
974                         break;
975                 }
976                 nbytes = (req->num_pages << PAGE_SHIFT) - req->page_offset;
977                 nbytes = min(nbytes_limit, nbytes);
978                 if (write)
979                         nres = fuse_send_write(req, file, inode, pos, nbytes,
980                                                current->files);
981                 else
982                         nres = fuse_send_read(req, file, inode, pos, nbytes,
983                                               current->files);
984                 fuse_release_user_pages(req, !write);
985                 if (req->out.h.error) {
986                         if (!res)
987                                 res = req->out.h.error;
988                         break;
989                 } else if (nres > nbytes) {
990                         res = -EIO;
991                         break;
992                 }
993                 count -= nres;
994                 res += nres;
995                 pos += nres;
996                 buf += nres;
997                 if (nres != nbytes)
998                         break;
999                 if (count) {
1000                         fuse_put_request(fc, req);
1001                         req = fuse_get_req(fc);
1002                         if (IS_ERR(req))
1003                                 break;
1004                 }
1005         }
1006         fuse_put_request(fc, req);
1007         if (res > 0) {
1008                 if (write)
1009                         fuse_write_update_size(inode, pos);
1010                 *ppos = pos;
1011         }
1012         fuse_invalidate_attr(inode);
1013
1014         return res;
1015 }
1016
1017 static ssize_t fuse_direct_read(struct file *file, char __user *buf,
1018                                      size_t count, loff_t *ppos)
1019 {
1020         return fuse_direct_io(file, buf, count, ppos, 0);
1021 }
1022
1023 static ssize_t fuse_direct_write(struct file *file, const char __user *buf,
1024                                  size_t count, loff_t *ppos)
1025 {
1026         struct inode *inode = file->f_path.dentry->d_inode;
1027         ssize_t res;
1028         /* Don't allow parallel writes to the same file */
1029         mutex_lock(&inode->i_mutex);
1030         res = generic_write_checks(file, ppos, &count, 0);
1031         if (!res)
1032                 res = fuse_direct_io(file, buf, count, ppos, 1);
1033         mutex_unlock(&inode->i_mutex);
1034         return res;
1035 }
1036
1037 static void fuse_writepage_free(struct fuse_conn *fc, struct fuse_req *req)
1038 {
1039         __free_page(req->pages[0]);
1040         fuse_file_put(req->ff);
1041         fuse_put_request(fc, req);
1042 }
1043
1044 static void fuse_writepage_finish(struct fuse_conn *fc, struct fuse_req *req)
1045 {
1046         struct inode *inode = req->inode;
1047         struct fuse_inode *fi = get_fuse_inode(inode);
1048         struct backing_dev_info *bdi = inode->i_mapping->backing_dev_info;
1049
1050         list_del(&req->writepages_entry);
1051         dec_bdi_stat(bdi, BDI_WRITEBACK);
1052         dec_zone_page_state(req->pages[0], NR_WRITEBACK_TEMP);
1053         bdi_writeout_inc(bdi);
1054         wake_up(&fi->page_waitq);
1055 }
1056
1057 /* Called under fc->lock, may release and reacquire it */
1058 static void fuse_send_writepage(struct fuse_conn *fc, struct fuse_req *req)
1059 {
1060         struct fuse_inode *fi = get_fuse_inode(req->inode);
1061         loff_t size = i_size_read(req->inode);
1062         struct fuse_write_in *inarg = &req->misc.write.in;
1063
1064         if (!fc->connected)
1065                 goto out_free;
1066
1067         if (inarg->offset + PAGE_CACHE_SIZE <= size) {
1068                 inarg->size = PAGE_CACHE_SIZE;
1069         } else if (inarg->offset < size) {
1070                 inarg->size = size & (PAGE_CACHE_SIZE - 1);
1071         } else {
1072                 /* Got truncated off completely */
1073                 goto out_free;
1074         }
1075
1076         req->in.args[1].size = inarg->size;
1077         fi->writectr++;
1078         request_send_background_locked(fc, req);
1079         return;
1080
1081  out_free:
1082         fuse_writepage_finish(fc, req);
1083         spin_unlock(&fc->lock);
1084         fuse_writepage_free(fc, req);
1085         spin_lock(&fc->lock);
1086 }
1087
1088 /*
1089  * If fi->writectr is positive (no truncate or fsync going on) send
1090  * all queued writepage requests.
1091  *
1092  * Called with fc->lock
1093  */
1094 void fuse_flush_writepages(struct inode *inode)
1095 {
1096         struct fuse_conn *fc = get_fuse_conn(inode);
1097         struct fuse_inode *fi = get_fuse_inode(inode);
1098         struct fuse_req *req;
1099
1100         while (fi->writectr >= 0 && !list_empty(&fi->queued_writes)) {
1101                 req = list_entry(fi->queued_writes.next, struct fuse_req, list);
1102                 list_del_init(&req->list);
1103                 fuse_send_writepage(fc, req);
1104         }
1105 }
1106
1107 static void fuse_writepage_end(struct fuse_conn *fc, struct fuse_req *req)
1108 {
1109         struct inode *inode = req->inode;
1110         struct fuse_inode *fi = get_fuse_inode(inode);
1111
1112         mapping_set_error(inode->i_mapping, req->out.h.error);
1113         spin_lock(&fc->lock);
1114         fi->writectr--;
1115         fuse_writepage_finish(fc, req);
1116         spin_unlock(&fc->lock);
1117         fuse_writepage_free(fc, req);
1118 }
1119
1120 static int fuse_writepage_locked(struct page *page)
1121 {
1122         struct address_space *mapping = page->mapping;
1123         struct inode *inode = mapping->host;
1124         struct fuse_conn *fc = get_fuse_conn(inode);
1125         struct fuse_inode *fi = get_fuse_inode(inode);
1126         struct fuse_req *req;
1127         struct fuse_file *ff;
1128         struct page *tmp_page;
1129
1130         set_page_writeback(page);
1131
1132         req = fuse_request_alloc_nofs();
1133         if (!req)
1134                 goto err;
1135
1136         tmp_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
1137         if (!tmp_page)
1138                 goto err_free;
1139
1140         spin_lock(&fc->lock);
1141         BUG_ON(list_empty(&fi->write_files));
1142         ff = list_entry(fi->write_files.next, struct fuse_file, write_entry);
1143         req->ff = fuse_file_get(ff);
1144         spin_unlock(&fc->lock);
1145
1146         fuse_write_fill(req, NULL, ff, inode, page_offset(page), 0, 1);
1147
1148         copy_highpage(tmp_page, page);
1149         req->num_pages = 1;
1150         req->pages[0] = tmp_page;
1151         req->page_offset = 0;
1152         req->end = fuse_writepage_end;
1153         req->inode = inode;
1154
1155         inc_bdi_stat(mapping->backing_dev_info, BDI_WRITEBACK);
1156         inc_zone_page_state(tmp_page, NR_WRITEBACK_TEMP);
1157         end_page_writeback(page);
1158
1159         spin_lock(&fc->lock);
1160         list_add(&req->writepages_entry, &fi->writepages);
1161         list_add_tail(&req->list, &fi->queued_writes);
1162         fuse_flush_writepages(inode);
1163         spin_unlock(&fc->lock);
1164
1165         return 0;
1166
1167 err_free:
1168         fuse_request_free(req);
1169 err:
1170         end_page_writeback(page);
1171         return -ENOMEM;
1172 }
1173
1174 static int fuse_writepage(struct page *page, struct writeback_control *wbc)
1175 {
1176         int err;
1177
1178         err = fuse_writepage_locked(page);
1179         unlock_page(page);
1180
1181         return err;
1182 }
1183
1184 static int fuse_launder_page(struct page *page)
1185 {
1186         int err = 0;
1187         if (clear_page_dirty_for_io(page)) {
1188                 struct inode *inode = page->mapping->host;
1189                 err = fuse_writepage_locked(page);
1190                 if (!err)
1191                         fuse_wait_on_page_writeback(inode, page->index);
1192         }
1193         return err;
1194 }
1195
1196 /*
1197  * Write back dirty pages now, because there may not be any suitable
1198  * open files later
1199  */
1200 static void fuse_vma_close(struct vm_area_struct *vma)
1201 {
1202         filemap_write_and_wait(vma->vm_file->f_mapping);
1203 }
1204
1205 /*
1206  * Wait for writeback against this page to complete before allowing it
1207  * to be marked dirty again, and hence written back again, possibly
1208  * before the previous writepage completed.
1209  *
1210  * Block here, instead of in ->writepage(), so that the userspace fs
1211  * can only block processes actually operating on the filesystem.
1212  *
1213  * Otherwise unprivileged userspace fs would be able to block
1214  * unrelated:
1215  *
1216  * - page migration
1217  * - sync(2)
1218  * - try_to_free_pages() with order > PAGE_ALLOC_COSTLY_ORDER
1219  */
1220 static int fuse_page_mkwrite(struct vm_area_struct *vma, struct page *page)
1221 {
1222         /*
1223          * Don't use page->mapping as it may become NULL from a
1224          * concurrent truncate.
1225          */
1226         struct inode *inode = vma->vm_file->f_mapping->host;
1227
1228         fuse_wait_on_page_writeback(inode, page->index);
1229         return 0;
1230 }
1231
1232 static struct vm_operations_struct fuse_file_vm_ops = {
1233         .close          = fuse_vma_close,
1234         .fault          = filemap_fault,
1235         .page_mkwrite   = fuse_page_mkwrite,
1236 };
1237
1238 static int fuse_file_mmap(struct file *file, struct vm_area_struct *vma)
1239 {
1240         if ((vma->vm_flags & VM_SHARED) && (vma->vm_flags & VM_MAYWRITE)) {
1241                 struct inode *inode = file->f_dentry->d_inode;
1242                 struct fuse_conn *fc = get_fuse_conn(inode);
1243                 struct fuse_inode *fi = get_fuse_inode(inode);
1244                 struct fuse_file *ff = file->private_data;
1245                 /*
1246                  * file may be written through mmap, so chain it onto the
1247                  * inodes's write_file list
1248                  */
1249                 spin_lock(&fc->lock);
1250                 if (list_empty(&ff->write_entry))
1251                         list_add(&ff->write_entry, &fi->write_files);
1252                 spin_unlock(&fc->lock);
1253         }
1254         file_accessed(file);
1255         vma->vm_ops = &fuse_file_vm_ops;
1256         return 0;
1257 }
1258
1259 static int convert_fuse_file_lock(const struct fuse_file_lock *ffl,
1260                                   struct file_lock *fl)
1261 {
1262         switch (ffl->type) {
1263         case F_UNLCK:
1264                 break;
1265
1266         case F_RDLCK:
1267         case F_WRLCK:
1268                 if (ffl->start > OFFSET_MAX || ffl->end > OFFSET_MAX ||
1269                     ffl->end < ffl->start)
1270                         return -EIO;
1271
1272                 fl->fl_start = ffl->start;
1273                 fl->fl_end = ffl->end;
1274                 fl->fl_pid = ffl->pid;
1275                 break;
1276
1277         default:
1278                 return -EIO;
1279         }
1280         fl->fl_type = ffl->type;
1281         return 0;
1282 }
1283
1284 static void fuse_lk_fill(struct fuse_req *req, struct file *file,
1285                          const struct file_lock *fl, int opcode, pid_t pid,
1286                          int flock)
1287 {
1288         struct inode *inode = file->f_path.dentry->d_inode;
1289         struct fuse_conn *fc = get_fuse_conn(inode);
1290         struct fuse_file *ff = file->private_data;
1291         struct fuse_lk_in *arg = &req->misc.lk_in;
1292
1293         arg->fh = ff->fh;
1294         arg->owner = fuse_lock_owner_id(fc, fl->fl_owner);
1295         arg->lk.start = fl->fl_start;
1296         arg->lk.end = fl->fl_end;
1297         arg->lk.type = fl->fl_type;
1298         arg->lk.pid = pid;
1299         if (flock)
1300                 arg->lk_flags |= FUSE_LK_FLOCK;
1301         req->in.h.opcode = opcode;
1302         req->in.h.nodeid = get_node_id(inode);
1303         req->in.numargs = 1;
1304         req->in.args[0].size = sizeof(*arg);
1305         req->in.args[0].value = arg;
1306 }
1307
1308 static int fuse_getlk(struct file *file, struct file_lock *fl)
1309 {
1310         struct inode *inode = file->f_path.dentry->d_inode;
1311         struct fuse_conn *fc = get_fuse_conn(inode);
1312         struct fuse_req *req;
1313         struct fuse_lk_out outarg;
1314         int err;
1315
1316         req = fuse_get_req(fc);
1317         if (IS_ERR(req))
1318                 return PTR_ERR(req);
1319
1320         fuse_lk_fill(req, file, fl, FUSE_GETLK, 0, 0);
1321         req->out.numargs = 1;
1322         req->out.args[0].size = sizeof(outarg);
1323         req->out.args[0].value = &outarg;
1324         request_send(fc, req);
1325         err = req->out.h.error;
1326         fuse_put_request(fc, req);
1327         if (!err)
1328                 err = convert_fuse_file_lock(&outarg.lk, fl);
1329
1330         return err;
1331 }
1332
1333 static int fuse_setlk(struct file *file, struct file_lock *fl, int flock)
1334 {
1335         struct inode *inode = file->f_path.dentry->d_inode;
1336         struct fuse_conn *fc = get_fuse_conn(inode);
1337         struct fuse_req *req;
1338         int opcode = (fl->fl_flags & FL_SLEEP) ? FUSE_SETLKW : FUSE_SETLK;
1339         pid_t pid = fl->fl_type != F_UNLCK ? current->tgid : 0;
1340         int err;
1341
1342         /* Unlock on close is handled by the flush method */
1343         if (fl->fl_flags & FL_CLOSE)
1344                 return 0;
1345
1346         req = fuse_get_req(fc);
1347         if (IS_ERR(req))
1348                 return PTR_ERR(req);
1349
1350         fuse_lk_fill(req, file, fl, opcode, pid, flock);
1351         request_send(fc, req);
1352         err = req->out.h.error;
1353         /* locking is restartable */
1354         if (err == -EINTR)
1355                 err = -ERESTARTSYS;
1356         fuse_put_request(fc, req);
1357         return err;
1358 }
1359
1360 static int fuse_file_lock(struct file *file, int cmd, struct file_lock *fl)
1361 {
1362         struct inode *inode = file->f_path.dentry->d_inode;
1363         struct fuse_conn *fc = get_fuse_conn(inode);
1364         int err;
1365
1366         if (cmd == F_GETLK) {
1367                 if (fc->no_lock) {
1368                         posix_test_lock(file, fl);
1369                         err = 0;
1370                 } else
1371                         err = fuse_getlk(file, fl);
1372         } else {
1373                 if (fc->no_lock)
1374                         err = posix_lock_file_wait(file, fl);
1375                 else
1376                         err = fuse_setlk(file, fl, 0);
1377         }
1378         return err;
1379 }
1380
1381 static int fuse_file_flock(struct file *file, int cmd, struct file_lock *fl)
1382 {
1383         struct inode *inode = file->f_path.dentry->d_inode;
1384         struct fuse_conn *fc = get_fuse_conn(inode);
1385         int err;
1386
1387         if (fc->no_lock) {
1388                 err = flock_lock_file_wait(file, fl);
1389         } else {
1390                 /* emulate flock with POSIX locks */
1391                 fl->fl_owner = (fl_owner_t) file;
1392                 err = fuse_setlk(file, fl, 1);
1393         }
1394
1395         return err;
1396 }
1397
1398 static sector_t fuse_bmap(struct address_space *mapping, sector_t block)
1399 {
1400         struct inode *inode = mapping->host;
1401         struct fuse_conn *fc = get_fuse_conn(inode);
1402         struct fuse_req *req;
1403         struct fuse_bmap_in inarg;
1404         struct fuse_bmap_out outarg;
1405         int err;
1406
1407         if (!inode->i_sb->s_bdev || fc->no_bmap)
1408                 return 0;
1409
1410         req = fuse_get_req(fc);
1411         if (IS_ERR(req))
1412                 return 0;
1413
1414         memset(&inarg, 0, sizeof(inarg));
1415         inarg.block = block;
1416         inarg.blocksize = inode->i_sb->s_blocksize;
1417         req->in.h.opcode = FUSE_BMAP;
1418         req->in.h.nodeid = get_node_id(inode);
1419         req->in.numargs = 1;
1420         req->in.args[0].size = sizeof(inarg);
1421         req->in.args[0].value = &inarg;
1422         req->out.numargs = 1;
1423         req->out.args[0].size = sizeof(outarg);
1424         req->out.args[0].value = &outarg;
1425         request_send(fc, req);
1426         err = req->out.h.error;
1427         fuse_put_request(fc, req);
1428         if (err == -ENOSYS)
1429                 fc->no_bmap = 1;
1430
1431         return err ? 0 : outarg.block;
1432 }
1433
1434 static loff_t fuse_file_llseek(struct file *file, loff_t offset, int origin)
1435 {
1436         loff_t retval;
1437         struct inode *inode = file->f_path.dentry->d_inode;
1438
1439         mutex_lock(&inode->i_mutex);
1440         switch (origin) {
1441         case SEEK_END:
1442                 offset += i_size_read(inode);
1443                 break;
1444         case SEEK_CUR:
1445                 offset += file->f_pos;
1446         }
1447         retval = -EINVAL;
1448         if (offset >= 0 && offset <= inode->i_sb->s_maxbytes) {
1449                 if (offset != file->f_pos) {
1450                         file->f_pos = offset;
1451                         file->f_version = 0;
1452                 }
1453                 retval = offset;
1454         }
1455         mutex_unlock(&inode->i_mutex);
1456         return retval;
1457 }
1458
1459 static const struct file_operations fuse_file_operations = {
1460         .llseek         = fuse_file_llseek,
1461         .read           = do_sync_read,
1462         .aio_read       = fuse_file_aio_read,
1463         .write          = do_sync_write,
1464         .aio_write      = fuse_file_aio_write,
1465         .mmap           = fuse_file_mmap,
1466         .open           = fuse_open,
1467         .flush          = fuse_flush,
1468         .release        = fuse_release,
1469         .fsync          = fuse_fsync,
1470         .lock           = fuse_file_lock,
1471         .flock          = fuse_file_flock,
1472         .splice_read    = generic_file_splice_read,
1473 };
1474
1475 static const struct file_operations fuse_direct_io_file_operations = {
1476         .llseek         = fuse_file_llseek,
1477         .read           = fuse_direct_read,
1478         .write          = fuse_direct_write,
1479         .open           = fuse_open,
1480         .flush          = fuse_flush,
1481         .release        = fuse_release,
1482         .fsync          = fuse_fsync,
1483         .lock           = fuse_file_lock,
1484         .flock          = fuse_file_flock,
1485         /* no mmap and splice_read */
1486 };
1487
1488 static const struct address_space_operations fuse_file_aops  = {
1489         .readpage       = fuse_readpage,
1490         .writepage      = fuse_writepage,
1491         .launder_page   = fuse_launder_page,
1492         .write_begin    = fuse_write_begin,
1493         .write_end      = fuse_write_end,
1494         .readpages      = fuse_readpages,
1495         .set_page_dirty = __set_page_dirty_nobuffers,
1496         .bmap           = fuse_bmap,
1497 };
1498
1499 void fuse_init_file_inode(struct inode *inode)
1500 {
1501         inode->i_fop = &fuse_file_operations;
1502         inode->i_data.a_ops = &fuse_file_aops;
1503 }