fuse: pass open flags to read and write
[linux-3.10.git] / 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->dentry);
81         mntput(req->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 fuse_conn *fc = get_fuse_conn(req->dentry->d_inode);
90                 req->end = fuse_release_end;
91                 request_send_background(fc, req);
92                 kfree(ff);
93         }
94 }
95
96 void fuse_finish_open(struct inode *inode, struct file *file,
97                       struct fuse_file *ff, struct fuse_open_out *outarg)
98 {
99         if (outarg->open_flags & FOPEN_DIRECT_IO)
100                 file->f_op = &fuse_direct_io_file_operations;
101         if (!(outarg->open_flags & FOPEN_KEEP_CACHE))
102                 invalidate_inode_pages2(inode->i_mapping);
103         ff->fh = outarg->fh;
104         file->private_data = fuse_file_get(ff);
105 }
106
107 int fuse_open_common(struct inode *inode, struct file *file, int isdir)
108 {
109         struct fuse_open_out outarg;
110         struct fuse_file *ff;
111         int err;
112
113         /* VFS checks this, but only _after_ ->open() */
114         if (file->f_flags & O_DIRECT)
115                 return -EINVAL;
116
117         err = generic_file_open(inode, file);
118         if (err)
119                 return err;
120
121         ff = fuse_file_alloc();
122         if (!ff)
123                 return -ENOMEM;
124
125         err = fuse_send_open(inode, file, isdir, &outarg);
126         if (err)
127                 fuse_file_free(ff);
128         else {
129                 if (isdir)
130                         outarg.open_flags &= ~FOPEN_DIRECT_IO;
131                 fuse_finish_open(inode, file, ff, &outarg);
132         }
133
134         return err;
135 }
136
137 void fuse_release_fill(struct fuse_file *ff, u64 nodeid, int flags, int opcode)
138 {
139         struct fuse_req *req = ff->reserved_req;
140         struct fuse_release_in *inarg = &req->misc.release_in;
141
142         inarg->fh = ff->fh;
143         inarg->flags = flags;
144         req->in.h.opcode = opcode;
145         req->in.h.nodeid = nodeid;
146         req->in.numargs = 1;
147         req->in.args[0].size = sizeof(struct fuse_release_in);
148         req->in.args[0].value = inarg;
149 }
150
151 int fuse_release_common(struct inode *inode, struct file *file, int isdir)
152 {
153         struct fuse_file *ff = file->private_data;
154         if (ff) {
155                 struct fuse_conn *fc = get_fuse_conn(inode);
156
157                 fuse_release_fill(ff, get_node_id(inode), file->f_flags,
158                                   isdir ? FUSE_RELEASEDIR : FUSE_RELEASE);
159
160                 /* Hold vfsmount and dentry until release is finished */
161                 ff->reserved_req->vfsmount = mntget(file->f_path.mnt);
162                 ff->reserved_req->dentry = dget(file->f_path.dentry);
163
164                 spin_lock(&fc->lock);
165                 list_del(&ff->write_entry);
166                 spin_unlock(&fc->lock);
167                 /*
168                  * Normally this will send the RELEASE request,
169                  * however if some asynchronous READ or WRITE requests
170                  * are outstanding, the sending will be delayed
171                  */
172                 fuse_file_put(ff);
173         }
174
175         /* Return value is ignored by VFS */
176         return 0;
177 }
178
179 static int fuse_open(struct inode *inode, struct file *file)
180 {
181         return fuse_open_common(inode, file, 0);
182 }
183
184 static int fuse_release(struct inode *inode, struct file *file)
185 {
186         return fuse_release_common(inode, file, 0);
187 }
188
189 /*
190  * Scramble the ID space with XTEA, so that the value of the files_struct
191  * pointer is not exposed to userspace.
192  */
193 u64 fuse_lock_owner_id(struct fuse_conn *fc, fl_owner_t id)
194 {
195         u32 *k = fc->scramble_key;
196         u64 v = (unsigned long) id;
197         u32 v0 = v;
198         u32 v1 = v >> 32;
199         u32 sum = 0;
200         int i;
201
202         for (i = 0; i < 32; i++) {
203                 v0 += ((v1 << 4 ^ v1 >> 5) + v1) ^ (sum + k[sum & 3]);
204                 sum += 0x9E3779B9;
205                 v1 += ((v0 << 4 ^ v0 >> 5) + v0) ^ (sum + k[sum>>11 & 3]);
206         }
207
208         return (u64) v0 + ((u64) v1 << 32);
209 }
210
211 static int fuse_flush(struct file *file, fl_owner_t id)
212 {
213         struct inode *inode = file->f_path.dentry->d_inode;
214         struct fuse_conn *fc = get_fuse_conn(inode);
215         struct fuse_file *ff = file->private_data;
216         struct fuse_req *req;
217         struct fuse_flush_in inarg;
218         int err;
219
220         if (is_bad_inode(inode))
221                 return -EIO;
222
223         if (fc->no_flush)
224                 return 0;
225
226         req = fuse_get_req_nofail(fc, file);
227         memset(&inarg, 0, sizeof(inarg));
228         inarg.fh = ff->fh;
229         inarg.lock_owner = fuse_lock_owner_id(fc, id);
230         req->in.h.opcode = FUSE_FLUSH;
231         req->in.h.nodeid = get_node_id(inode);
232         req->in.numargs = 1;
233         req->in.args[0].size = sizeof(inarg);
234         req->in.args[0].value = &inarg;
235         req->force = 1;
236         request_send(fc, req);
237         err = req->out.h.error;
238         fuse_put_request(fc, req);
239         if (err == -ENOSYS) {
240                 fc->no_flush = 1;
241                 err = 0;
242         }
243         return err;
244 }
245
246 int fuse_fsync_common(struct file *file, struct dentry *de, int datasync,
247                       int isdir)
248 {
249         struct inode *inode = de->d_inode;
250         struct fuse_conn *fc = get_fuse_conn(inode);
251         struct fuse_file *ff = file->private_data;
252         struct fuse_req *req;
253         struct fuse_fsync_in inarg;
254         int err;
255
256         if (is_bad_inode(inode))
257                 return -EIO;
258
259         if ((!isdir && fc->no_fsync) || (isdir && fc->no_fsyncdir))
260                 return 0;
261
262         req = fuse_get_req(fc);
263         if (IS_ERR(req))
264                 return PTR_ERR(req);
265
266         memset(&inarg, 0, sizeof(inarg));
267         inarg.fh = ff->fh;
268         inarg.fsync_flags = datasync ? 1 : 0;
269         req->in.h.opcode = isdir ? FUSE_FSYNCDIR : FUSE_FSYNC;
270         req->in.h.nodeid = get_node_id(inode);
271         req->in.numargs = 1;
272         req->in.args[0].size = sizeof(inarg);
273         req->in.args[0].value = &inarg;
274         request_send(fc, req);
275         err = req->out.h.error;
276         fuse_put_request(fc, req);
277         if (err == -ENOSYS) {
278                 if (isdir)
279                         fc->no_fsyncdir = 1;
280                 else
281                         fc->no_fsync = 1;
282                 err = 0;
283         }
284         return err;
285 }
286
287 static int fuse_fsync(struct file *file, struct dentry *de, int datasync)
288 {
289         return fuse_fsync_common(file, de, datasync, 0);
290 }
291
292 void fuse_read_fill(struct fuse_req *req, struct file *file,
293                     struct inode *inode, loff_t pos, size_t count, int opcode)
294 {
295         struct fuse_read_in *inarg = &req->misc.read_in;
296         struct fuse_file *ff = file->private_data;
297
298         inarg->fh = ff->fh;
299         inarg->offset = pos;
300         inarg->size = count;
301         inarg->flags = file->f_flags;
302         req->in.h.opcode = opcode;
303         req->in.h.nodeid = get_node_id(inode);
304         req->in.numargs = 1;
305         req->in.args[0].size = sizeof(struct fuse_read_in);
306         req->in.args[0].value = inarg;
307         req->out.argpages = 1;
308         req->out.argvar = 1;
309         req->out.numargs = 1;
310         req->out.args[0].size = count;
311 }
312
313 static size_t fuse_send_read(struct fuse_req *req, struct file *file,
314                              struct inode *inode, loff_t pos, size_t count,
315                              fl_owner_t owner)
316 {
317         struct fuse_conn *fc = get_fuse_conn(inode);
318
319         fuse_read_fill(req, file, inode, pos, count, FUSE_READ);
320         if (owner != NULL) {
321                 struct fuse_read_in *inarg = &req->misc.read_in;
322
323                 inarg->read_flags |= FUSE_READ_LOCKOWNER;
324                 inarg->lock_owner = fuse_lock_owner_id(fc, owner);
325         }
326         request_send(fc, req);
327         return req->out.args[0].size;
328 }
329
330 static int fuse_readpage(struct file *file, struct page *page)
331 {
332         struct inode *inode = page->mapping->host;
333         struct fuse_conn *fc = get_fuse_conn(inode);
334         struct fuse_req *req;
335         int err;
336
337         err = -EIO;
338         if (is_bad_inode(inode))
339                 goto out;
340
341         req = fuse_get_req(fc);
342         err = PTR_ERR(req);
343         if (IS_ERR(req))
344                 goto out;
345
346         req->out.page_zeroing = 1;
347         req->num_pages = 1;
348         req->pages[0] = page;
349         fuse_send_read(req, file, inode, page_offset(page), PAGE_CACHE_SIZE,
350                        NULL);
351         err = req->out.h.error;
352         fuse_put_request(fc, req);
353         if (!err)
354                 SetPageUptodate(page);
355         fuse_invalidate_attr(inode); /* atime changed */
356  out:
357         unlock_page(page);
358         return err;
359 }
360
361 static void fuse_readpages_end(struct fuse_conn *fc, struct fuse_req *req)
362 {
363         int i;
364
365         fuse_invalidate_attr(req->pages[0]->mapping->host); /* atime changed */
366
367         for (i = 0; i < req->num_pages; i++) {
368                 struct page *page = req->pages[i];
369                 if (!req->out.h.error)
370                         SetPageUptodate(page);
371                 else
372                         SetPageError(page);
373                 unlock_page(page);
374         }
375         if (req->ff)
376                 fuse_file_put(req->ff);
377         fuse_put_request(fc, req);
378 }
379
380 static void fuse_send_readpages(struct fuse_req *req, struct file *file,
381                                 struct inode *inode)
382 {
383         struct fuse_conn *fc = get_fuse_conn(inode);
384         loff_t pos = page_offset(req->pages[0]);
385         size_t count = req->num_pages << PAGE_CACHE_SHIFT;
386         req->out.page_zeroing = 1;
387         fuse_read_fill(req, file, inode, pos, count, FUSE_READ);
388         if (fc->async_read) {
389                 struct fuse_file *ff = file->private_data;
390                 req->ff = fuse_file_get(ff);
391                 req->end = fuse_readpages_end;
392                 request_send_background(fc, req);
393         } else {
394                 request_send(fc, req);
395                 fuse_readpages_end(fc, req);
396         }
397 }
398
399 struct fuse_fill_data {
400         struct fuse_req *req;
401         struct file *file;
402         struct inode *inode;
403 };
404
405 static int fuse_readpages_fill(void *_data, struct page *page)
406 {
407         struct fuse_fill_data *data = _data;
408         struct fuse_req *req = data->req;
409         struct inode *inode = data->inode;
410         struct fuse_conn *fc = get_fuse_conn(inode);
411
412         if (req->num_pages &&
413             (req->num_pages == FUSE_MAX_PAGES_PER_REQ ||
414              (req->num_pages + 1) * PAGE_CACHE_SIZE > fc->max_read ||
415              req->pages[req->num_pages - 1]->index + 1 != page->index)) {
416                 fuse_send_readpages(req, data->file, inode);
417                 data->req = req = fuse_get_req(fc);
418                 if (IS_ERR(req)) {
419                         unlock_page(page);
420                         return PTR_ERR(req);
421                 }
422         }
423         req->pages[req->num_pages] = page;
424         req->num_pages ++;
425         return 0;
426 }
427
428 static int fuse_readpages(struct file *file, struct address_space *mapping,
429                           struct list_head *pages, unsigned nr_pages)
430 {
431         struct inode *inode = mapping->host;
432         struct fuse_conn *fc = get_fuse_conn(inode);
433         struct fuse_fill_data data;
434         int err;
435
436         err = -EIO;
437         if (is_bad_inode(inode))
438                 goto out;
439
440         data.file = file;
441         data.inode = inode;
442         data.req = fuse_get_req(fc);
443         err = PTR_ERR(data.req);
444         if (IS_ERR(data.req))
445                 goto out;
446
447         err = read_cache_pages(mapping, pages, fuse_readpages_fill, &data);
448         if (!err) {
449                 if (data.req->num_pages)
450                         fuse_send_readpages(data.req, file, inode);
451                 else
452                         fuse_put_request(fc, data.req);
453         }
454 out:
455         return err;
456 }
457
458 static ssize_t fuse_file_aio_read(struct kiocb *iocb, const struct iovec *iov,
459                                   unsigned long nr_segs, loff_t pos)
460 {
461         struct inode *inode = iocb->ki_filp->f_mapping->host;
462
463         if (pos + iov_length(iov, nr_segs) > i_size_read(inode)) {
464                 int err;
465                 /*
466                  * If trying to read past EOF, make sure the i_size
467                  * attribute is up-to-date.
468                  */
469                 err = fuse_update_attributes(inode, NULL, iocb->ki_filp, NULL);
470                 if (err)
471                         return err;
472         }
473
474         return generic_file_aio_read(iocb, iov, nr_segs, pos);
475 }
476
477 static void fuse_write_fill(struct fuse_req *req, struct file *file,
478                             struct inode *inode, loff_t pos, size_t count,
479                             int writepage)
480 {
481         struct fuse_conn *fc = get_fuse_conn(inode);
482         struct fuse_file *ff = file->private_data;
483         struct fuse_write_in *inarg = &req->misc.write.in;
484         struct fuse_write_out *outarg = &req->misc.write.out;
485
486         memset(inarg, 0, sizeof(struct fuse_write_in));
487         inarg->fh = ff->fh;
488         inarg->offset = pos;
489         inarg->size = count;
490         inarg->write_flags = writepage ? FUSE_WRITE_CACHE : 0;
491         inarg->flags = file->f_flags;
492         req->in.h.opcode = FUSE_WRITE;
493         req->in.h.nodeid = get_node_id(inode);
494         req->in.argpages = 1;
495         req->in.numargs = 2;
496         if (fc->minor < 9)
497                 req->in.args[0].size = FUSE_COMPAT_WRITE_IN_SIZE;
498         else
499                 req->in.args[0].size = sizeof(struct fuse_write_in);
500         req->in.args[0].value = inarg;
501         req->in.args[1].size = count;
502         req->out.numargs = 1;
503         req->out.args[0].size = sizeof(struct fuse_write_out);
504         req->out.args[0].value = outarg;
505 }
506
507 static size_t fuse_send_write(struct fuse_req *req, struct file *file,
508                               struct inode *inode, loff_t pos, size_t count,
509                               fl_owner_t owner)
510 {
511         struct fuse_conn *fc = get_fuse_conn(inode);
512         fuse_write_fill(req, file, inode, pos, count, 0);
513         if (owner != NULL) {
514                 struct fuse_write_in *inarg = &req->misc.write.in;
515                 inarg->write_flags |= FUSE_WRITE_LOCKOWNER;
516                 inarg->lock_owner = fuse_lock_owner_id(fc, owner);
517         }
518         request_send(fc, req);
519         return req->misc.write.out.size;
520 }
521
522 static int fuse_write_begin(struct file *file, struct address_space *mapping,
523                         loff_t pos, unsigned len, unsigned flags,
524                         struct page **pagep, void **fsdata)
525 {
526         pgoff_t index = pos >> PAGE_CACHE_SHIFT;
527
528         *pagep = __grab_cache_page(mapping, index);
529         if (!*pagep)
530                 return -ENOMEM;
531         return 0;
532 }
533
534 static int fuse_buffered_write(struct file *file, struct inode *inode,
535                                loff_t pos, unsigned count, struct page *page)
536 {
537         int err;
538         size_t nres;
539         struct fuse_conn *fc = get_fuse_conn(inode);
540         struct fuse_inode *fi = get_fuse_inode(inode);
541         unsigned offset = pos & (PAGE_CACHE_SIZE - 1);
542         struct fuse_req *req;
543
544         if (is_bad_inode(inode))
545                 return -EIO;
546
547         req = fuse_get_req(fc);
548         if (IS_ERR(req))
549                 return PTR_ERR(req);
550
551         req->num_pages = 1;
552         req->pages[0] = page;
553         req->page_offset = offset;
554         nres = fuse_send_write(req, file, inode, pos, count, NULL);
555         err = req->out.h.error;
556         fuse_put_request(fc, req);
557         if (!err && !nres)
558                 err = -EIO;
559         if (!err) {
560                 pos += nres;
561                 spin_lock(&fc->lock);
562                 fi->attr_version = ++fc->attr_version;
563                 if (pos > inode->i_size)
564                         i_size_write(inode, pos);
565                 spin_unlock(&fc->lock);
566
567                 if (count == PAGE_CACHE_SIZE)
568                         SetPageUptodate(page);
569         }
570         fuse_invalidate_attr(inode);
571         return err ? err : nres;
572 }
573
574 static int fuse_write_end(struct file *file, struct address_space *mapping,
575                         loff_t pos, unsigned len, unsigned copied,
576                         struct page *page, void *fsdata)
577 {
578         struct inode *inode = mapping->host;
579         int res = 0;
580
581         if (copied)
582                 res = fuse_buffered_write(file, inode, pos, copied, page);
583
584         unlock_page(page);
585         page_cache_release(page);
586         return res;
587 }
588
589 static void fuse_release_user_pages(struct fuse_req *req, int write)
590 {
591         unsigned i;
592
593         for (i = 0; i < req->num_pages; i++) {
594                 struct page *page = req->pages[i];
595                 if (write)
596                         set_page_dirty_lock(page);
597                 put_page(page);
598         }
599 }
600
601 static int fuse_get_user_pages(struct fuse_req *req, const char __user *buf,
602                                unsigned nbytes, int write)
603 {
604         unsigned long user_addr = (unsigned long) buf;
605         unsigned offset = user_addr & ~PAGE_MASK;
606         int npages;
607
608         /* This doesn't work with nfsd */
609         if (!current->mm)
610                 return -EPERM;
611
612         nbytes = min(nbytes, (unsigned) FUSE_MAX_PAGES_PER_REQ << PAGE_SHIFT);
613         npages = (nbytes + offset + PAGE_SIZE - 1) >> PAGE_SHIFT;
614         npages = min(max(npages, 1), FUSE_MAX_PAGES_PER_REQ);
615         down_read(&current->mm->mmap_sem);
616         npages = get_user_pages(current, current->mm, user_addr, npages, write,
617                                 0, req->pages, NULL);
618         up_read(&current->mm->mmap_sem);
619         if (npages < 0)
620                 return npages;
621
622         req->num_pages = npages;
623         req->page_offset = offset;
624         return 0;
625 }
626
627 static ssize_t fuse_direct_io(struct file *file, const char __user *buf,
628                               size_t count, loff_t *ppos, int write)
629 {
630         struct inode *inode = file->f_path.dentry->d_inode;
631         struct fuse_conn *fc = get_fuse_conn(inode);
632         size_t nmax = write ? fc->max_write : fc->max_read;
633         loff_t pos = *ppos;
634         ssize_t res = 0;
635         struct fuse_req *req;
636
637         if (is_bad_inode(inode))
638                 return -EIO;
639
640         req = fuse_get_req(fc);
641         if (IS_ERR(req))
642                 return PTR_ERR(req);
643
644         while (count) {
645                 size_t nres;
646                 size_t nbytes = min(count, nmax);
647                 int err = fuse_get_user_pages(req, buf, nbytes, !write);
648                 if (err) {
649                         res = err;
650                         break;
651                 }
652                 nbytes = (req->num_pages << PAGE_SHIFT) - req->page_offset;
653                 nbytes = min(count, nbytes);
654                 if (write)
655                         nres = fuse_send_write(req, file, inode, pos, nbytes,
656                                                current->files);
657                 else
658                         nres = fuse_send_read(req, file, inode, pos, nbytes,
659                                               current->files);
660                 fuse_release_user_pages(req, !write);
661                 if (req->out.h.error) {
662                         if (!res)
663                                 res = req->out.h.error;
664                         break;
665                 } else if (nres > nbytes) {
666                         res = -EIO;
667                         break;
668                 }
669                 count -= nres;
670                 res += nres;
671                 pos += nres;
672                 buf += nres;
673                 if (nres != nbytes)
674                         break;
675                 if (count) {
676                         fuse_put_request(fc, req);
677                         req = fuse_get_req(fc);
678                         if (IS_ERR(req))
679                                 break;
680                 }
681         }
682         fuse_put_request(fc, req);
683         if (res > 0) {
684                 if (write) {
685                         spin_lock(&fc->lock);
686                         if (pos > inode->i_size)
687                                 i_size_write(inode, pos);
688                         spin_unlock(&fc->lock);
689                 }
690                 *ppos = pos;
691         }
692         fuse_invalidate_attr(inode);
693
694         return res;
695 }
696
697 static ssize_t fuse_direct_read(struct file *file, char __user *buf,
698                                      size_t count, loff_t *ppos)
699 {
700         return fuse_direct_io(file, buf, count, ppos, 0);
701 }
702
703 static ssize_t fuse_direct_write(struct file *file, const char __user *buf,
704                                  size_t count, loff_t *ppos)
705 {
706         struct inode *inode = file->f_path.dentry->d_inode;
707         ssize_t res;
708         /* Don't allow parallel writes to the same file */
709         mutex_lock(&inode->i_mutex);
710         res = generic_write_checks(file, ppos, &count, 0);
711         if (!res)
712                 res = fuse_direct_io(file, buf, count, ppos, 1);
713         mutex_unlock(&inode->i_mutex);
714         return res;
715 }
716
717 static int fuse_file_mmap(struct file *file, struct vm_area_struct *vma)
718 {
719         if ((vma->vm_flags & VM_SHARED)) {
720                 if ((vma->vm_flags & VM_WRITE))
721                         return -ENODEV;
722                 else
723                         vma->vm_flags &= ~VM_MAYWRITE;
724         }
725         return generic_file_mmap(file, vma);
726 }
727
728 static int fuse_set_page_dirty(struct page *page)
729 {
730         printk("fuse_set_page_dirty: should not happen\n");
731         dump_stack();
732         return 0;
733 }
734
735 static int convert_fuse_file_lock(const struct fuse_file_lock *ffl,
736                                   struct file_lock *fl)
737 {
738         switch (ffl->type) {
739         case F_UNLCK:
740                 break;
741
742         case F_RDLCK:
743         case F_WRLCK:
744                 if (ffl->start > OFFSET_MAX || ffl->end > OFFSET_MAX ||
745                     ffl->end < ffl->start)
746                         return -EIO;
747
748                 fl->fl_start = ffl->start;
749                 fl->fl_end = ffl->end;
750                 fl->fl_pid = ffl->pid;
751                 break;
752
753         default:
754                 return -EIO;
755         }
756         fl->fl_type = ffl->type;
757         return 0;
758 }
759
760 static void fuse_lk_fill(struct fuse_req *req, struct file *file,
761                          const struct file_lock *fl, int opcode, pid_t pid,
762                          int flock)
763 {
764         struct inode *inode = file->f_path.dentry->d_inode;
765         struct fuse_conn *fc = get_fuse_conn(inode);
766         struct fuse_file *ff = file->private_data;
767         struct fuse_lk_in *arg = &req->misc.lk_in;
768
769         arg->fh = ff->fh;
770         arg->owner = fuse_lock_owner_id(fc, fl->fl_owner);
771         arg->lk.start = fl->fl_start;
772         arg->lk.end = fl->fl_end;
773         arg->lk.type = fl->fl_type;
774         arg->lk.pid = pid;
775         if (flock)
776                 arg->lk_flags |= FUSE_LK_FLOCK;
777         req->in.h.opcode = opcode;
778         req->in.h.nodeid = get_node_id(inode);
779         req->in.numargs = 1;
780         req->in.args[0].size = sizeof(*arg);
781         req->in.args[0].value = arg;
782 }
783
784 static int fuse_getlk(struct file *file, struct file_lock *fl)
785 {
786         struct inode *inode = file->f_path.dentry->d_inode;
787         struct fuse_conn *fc = get_fuse_conn(inode);
788         struct fuse_req *req;
789         struct fuse_lk_out outarg;
790         int err;
791
792         req = fuse_get_req(fc);
793         if (IS_ERR(req))
794                 return PTR_ERR(req);
795
796         fuse_lk_fill(req, file, fl, FUSE_GETLK, 0, 0);
797         req->out.numargs = 1;
798         req->out.args[0].size = sizeof(outarg);
799         req->out.args[0].value = &outarg;
800         request_send(fc, req);
801         err = req->out.h.error;
802         fuse_put_request(fc, req);
803         if (!err)
804                 err = convert_fuse_file_lock(&outarg.lk, fl);
805
806         return err;
807 }
808
809 static int fuse_setlk(struct file *file, struct file_lock *fl, int flock)
810 {
811         struct inode *inode = file->f_path.dentry->d_inode;
812         struct fuse_conn *fc = get_fuse_conn(inode);
813         struct fuse_req *req;
814         int opcode = (fl->fl_flags & FL_SLEEP) ? FUSE_SETLKW : FUSE_SETLK;
815         pid_t pid = fl->fl_type != F_UNLCK ? current->tgid : 0;
816         int err;
817
818         /* Unlock on close is handled by the flush method */
819         if (fl->fl_flags & FL_CLOSE)
820                 return 0;
821
822         req = fuse_get_req(fc);
823         if (IS_ERR(req))
824                 return PTR_ERR(req);
825
826         fuse_lk_fill(req, file, fl, opcode, pid, flock);
827         request_send(fc, req);
828         err = req->out.h.error;
829         /* locking is restartable */
830         if (err == -EINTR)
831                 err = -ERESTARTSYS;
832         fuse_put_request(fc, req);
833         return err;
834 }
835
836 static int fuse_file_lock(struct file *file, int cmd, struct file_lock *fl)
837 {
838         struct inode *inode = file->f_path.dentry->d_inode;
839         struct fuse_conn *fc = get_fuse_conn(inode);
840         int err;
841
842         if (cmd == F_GETLK) {
843                 if (fc->no_lock) {
844                         posix_test_lock(file, fl);
845                         err = 0;
846                 } else
847                         err = fuse_getlk(file, fl);
848         } else {
849                 if (fc->no_lock)
850                         err = posix_lock_file_wait(file, fl);
851                 else
852                         err = fuse_setlk(file, fl, 0);
853         }
854         return err;
855 }
856
857 static int fuse_file_flock(struct file *file, int cmd, struct file_lock *fl)
858 {
859         struct inode *inode = file->f_path.dentry->d_inode;
860         struct fuse_conn *fc = get_fuse_conn(inode);
861         int err;
862
863         if (fc->no_lock) {
864                 err = flock_lock_file_wait(file, fl);
865         } else {
866                 /* emulate flock with POSIX locks */
867                 fl->fl_owner = (fl_owner_t) file;
868                 err = fuse_setlk(file, fl, 1);
869         }
870
871         return err;
872 }
873
874 static sector_t fuse_bmap(struct address_space *mapping, sector_t block)
875 {
876         struct inode *inode = mapping->host;
877         struct fuse_conn *fc = get_fuse_conn(inode);
878         struct fuse_req *req;
879         struct fuse_bmap_in inarg;
880         struct fuse_bmap_out outarg;
881         int err;
882
883         if (!inode->i_sb->s_bdev || fc->no_bmap)
884                 return 0;
885
886         req = fuse_get_req(fc);
887         if (IS_ERR(req))
888                 return 0;
889
890         memset(&inarg, 0, sizeof(inarg));
891         inarg.block = block;
892         inarg.blocksize = inode->i_sb->s_blocksize;
893         req->in.h.opcode = FUSE_BMAP;
894         req->in.h.nodeid = get_node_id(inode);
895         req->in.numargs = 1;
896         req->in.args[0].size = sizeof(inarg);
897         req->in.args[0].value = &inarg;
898         req->out.numargs = 1;
899         req->out.args[0].size = sizeof(outarg);
900         req->out.args[0].value = &outarg;
901         request_send(fc, req);
902         err = req->out.h.error;
903         fuse_put_request(fc, req);
904         if (err == -ENOSYS)
905                 fc->no_bmap = 1;
906
907         return err ? 0 : outarg.block;
908 }
909
910 static const struct file_operations fuse_file_operations = {
911         .llseek         = generic_file_llseek,
912         .read           = do_sync_read,
913         .aio_read       = fuse_file_aio_read,
914         .write          = do_sync_write,
915         .aio_write      = generic_file_aio_write,
916         .mmap           = fuse_file_mmap,
917         .open           = fuse_open,
918         .flush          = fuse_flush,
919         .release        = fuse_release,
920         .fsync          = fuse_fsync,
921         .lock           = fuse_file_lock,
922         .flock          = fuse_file_flock,
923         .splice_read    = generic_file_splice_read,
924 };
925
926 static const struct file_operations fuse_direct_io_file_operations = {
927         .llseek         = generic_file_llseek,
928         .read           = fuse_direct_read,
929         .write          = fuse_direct_write,
930         .open           = fuse_open,
931         .flush          = fuse_flush,
932         .release        = fuse_release,
933         .fsync          = fuse_fsync,
934         .lock           = fuse_file_lock,
935         .flock          = fuse_file_flock,
936         /* no mmap and splice_read */
937 };
938
939 static const struct address_space_operations fuse_file_aops  = {
940         .readpage       = fuse_readpage,
941         .write_begin    = fuse_write_begin,
942         .write_end      = fuse_write_end,
943         .readpages      = fuse_readpages,
944         .set_page_dirty = fuse_set_page_dirty,
945         .bmap           = fuse_bmap,
946 };
947
948 void fuse_init_file_inode(struct inode *inode)
949 {
950         inode->i_fop = &fuse_file_operations;
951         inode->i_data.a_ops = &fuse_file_aops;
952 }