1 /*
2 FUSE: Filesystem in Userspace
3 Copyright (C) 2001-2008 Miklos Szeredi <miklos@szeredi.hu>
4
5 This program can be distributed under the terms of the GNU GPL.
6 See the file COPYING.
7 */
8
9 #include "fuse_i.h"
10
11 #include <linux/pagemap.h>
12 #include <linux/file.h>
13 #include <linux/sched.h>
14 #include <linux/namei.h>
15 #include <linux/slab.h>
16
17 #if BITS_PER_LONG >= 64
fuse_dentry_settime(struct dentry * entry,u64 time)18 static inline void fuse_dentry_settime(struct dentry *entry, u64 time)
19 {
20 entry->d_time = time;
21 }
22
fuse_dentry_time(struct dentry * entry)23 static inline u64 fuse_dentry_time(struct dentry *entry)
24 {
25 return entry->d_time;
26 }
27 #else
28 /*
29 * On 32 bit archs store the high 32 bits of time in d_fsdata
30 */
fuse_dentry_settime(struct dentry * entry,u64 time)31 static void fuse_dentry_settime(struct dentry *entry, u64 time)
32 {
33 entry->d_time = time;
34 entry->d_fsdata = (void *) (unsigned long) (time >> 32);
35 }
36
fuse_dentry_time(struct dentry * entry)37 static u64 fuse_dentry_time(struct dentry *entry)
38 {
39 return (u64) entry->d_time +
40 ((u64) (unsigned long) entry->d_fsdata << 32);
41 }
42 #endif
43
44 /*
45 * FUSE caches dentries and attributes with separate timeout. The
46 * time in jiffies until the dentry/attributes are valid is stored in
47 * dentry->d_time and fuse_inode->i_time respectively.
48 */
49
50 /*
51 * Calculate the time in jiffies until a dentry/attributes are valid
52 */
time_to_jiffies(unsigned long sec,unsigned long nsec)53 static u64 time_to_jiffies(unsigned long sec, unsigned long nsec)
54 {
55 if (sec || nsec) {
56 struct timespec ts = {sec, nsec};
57 return get_jiffies_64() + timespec_to_jiffies(&ts);
58 } else
59 return 0;
60 }
61
62 /*
63 * Set dentry and possibly attribute timeouts from the lookup/mk*
64 * replies
65 */
fuse_change_entry_timeout(struct dentry * entry,struct fuse_entry_out * o)66 static void fuse_change_entry_timeout(struct dentry *entry,
67 struct fuse_entry_out *o)
68 {
69 fuse_dentry_settime(entry,
70 time_to_jiffies(o->entry_valid, o->entry_valid_nsec));
71 }
72
attr_timeout(struct fuse_attr_out * o)73 static u64 attr_timeout(struct fuse_attr_out *o)
74 {
75 return time_to_jiffies(o->attr_valid, o->attr_valid_nsec);
76 }
77
entry_attr_timeout(struct fuse_entry_out * o)78 static u64 entry_attr_timeout(struct fuse_entry_out *o)
79 {
80 return time_to_jiffies(o->attr_valid, o->attr_valid_nsec);
81 }
82
83 /*
84 * Mark the attributes as stale, so that at the next call to
85 * ->getattr() they will be fetched from userspace
86 */
fuse_invalidate_attr(struct inode * inode)87 void fuse_invalidate_attr(struct inode *inode)
88 {
89 get_fuse_inode(inode)->i_time = 0;
90 }
91
92 /*
93 * Just mark the entry as stale, so that a next attempt to look it up
94 * will result in a new lookup call to userspace
95 *
96 * This is called when a dentry is about to become negative and the
97 * timeout is unknown (unlink, rmdir, rename and in some cases
98 * lookup)
99 */
fuse_invalidate_entry_cache(struct dentry * entry)100 void fuse_invalidate_entry_cache(struct dentry *entry)
101 {
102 fuse_dentry_settime(entry, 0);
103 }
104
105 /*
106 * Same as fuse_invalidate_entry_cache(), but also try to remove the
107 * dentry from the hash
108 */
fuse_invalidate_entry(struct dentry * entry)109 static void fuse_invalidate_entry(struct dentry *entry)
110 {
111 d_invalidate(entry);
112 fuse_invalidate_entry_cache(entry);
113 }
114
fuse_lookup_init(struct fuse_conn * fc,struct fuse_req * req,u64 nodeid,struct qstr * name,struct fuse_entry_out * outarg)115 static void fuse_lookup_init(struct fuse_conn *fc, struct fuse_req *req,
116 u64 nodeid, struct qstr *name,
117 struct fuse_entry_out *outarg)
118 {
119 memset(outarg, 0, sizeof(struct fuse_entry_out));
120 req->in.h.opcode = FUSE_LOOKUP;
121 req->in.h.nodeid = nodeid;
122 req->in.numargs = 1;
123 req->in.args[0].size = name->len + 1;
124 req->in.args[0].value = name->name;
125 req->out.numargs = 1;
126 if (fc->minor < 9)
127 req->out.args[0].size = FUSE_COMPAT_ENTRY_OUT_SIZE;
128 else
129 req->out.args[0].size = sizeof(struct fuse_entry_out);
130 req->out.args[0].value = outarg;
131 }
132
fuse_get_attr_version(struct fuse_conn * fc)133 u64 fuse_get_attr_version(struct fuse_conn *fc)
134 {
135 u64 curr_version;
136
137 /*
138 * The spin lock isn't actually needed on 64bit archs, but we
139 * don't yet care too much about such optimizations.
140 */
141 spin_lock(&fc->lock);
142 curr_version = fc->attr_version;
143 spin_unlock(&fc->lock);
144
145 return curr_version;
146 }
147
148 /*
149 * Check whether the dentry is still valid
150 *
151 * If the entry validity timeout has expired and the dentry is
152 * positive, try to redo the lookup. If the lookup results in a
153 * different inode, then let the VFS invalidate the dentry and redo
154 * the lookup once more. If the lookup results in the same inode,
155 * then refresh the attributes, timeouts and mark the dentry valid.
156 */
fuse_dentry_revalidate(struct dentry * entry,struct nameidata * nd)157 static int fuse_dentry_revalidate(struct dentry *entry, struct nameidata *nd)
158 {
159 struct inode *inode;
160
161 inode = ACCESS_ONCE(entry->d_inode);
162 if (inode && is_bad_inode(inode))
163 return 0;
164 else if (fuse_dentry_time(entry) < get_jiffies_64()) {
165 int err;
166 struct fuse_entry_out outarg;
167 struct fuse_conn *fc;
168 struct fuse_req *req;
169 struct fuse_forget_link *forget;
170 struct dentry *parent;
171 u64 attr_version;
172
173 /* For negative dentries, always do a fresh lookup */
174 if (!inode)
175 return 0;
176
177 if (nd && (nd->flags & LOOKUP_RCU))
178 return -ECHILD;
179
180 fc = get_fuse_conn(inode);
181 req = fuse_get_req(fc);
182 if (IS_ERR(req))
183 return 0;
184
185 forget = fuse_alloc_forget();
186 if (!forget) {
187 fuse_put_request(fc, req);
188 return 0;
189 }
190
191 attr_version = fuse_get_attr_version(fc);
192
193 parent = dget_parent(entry);
194 fuse_lookup_init(fc, req, get_node_id(parent->d_inode),
195 &entry->d_name, &outarg);
196 fuse_request_send(fc, req);
197 dput(parent);
198 err = req->out.h.error;
199 fuse_put_request(fc, req);
200 /* Zero nodeid is same as -ENOENT */
201 if (!err && !outarg.nodeid)
202 err = -ENOENT;
203 if (!err) {
204 struct fuse_inode *fi = get_fuse_inode(inode);
205 if (outarg.nodeid != get_node_id(inode)) {
206 fuse_queue_forget(fc, forget, outarg.nodeid, 1);
207 return 0;
208 }
209 spin_lock(&fc->lock);
210 fi->nlookup++;
211 spin_unlock(&fc->lock);
212 }
213 kfree(forget);
214 if (err || (outarg.attr.mode ^ inode->i_mode) & S_IFMT)
215 return 0;
216
217 fuse_change_attributes(inode, &outarg.attr,
218 entry_attr_timeout(&outarg),
219 attr_version);
220 fuse_change_entry_timeout(entry, &outarg);
221 }
222 return 1;
223 }
224
invalid_nodeid(u64 nodeid)225 static int invalid_nodeid(u64 nodeid)
226 {
227 return !nodeid || nodeid == FUSE_ROOT_ID;
228 }
229
230 const struct dentry_operations fuse_dentry_operations = {
231 .d_revalidate = fuse_dentry_revalidate,
232 };
233
fuse_valid_type(int m)234 int fuse_valid_type(int m)
235 {
236 return S_ISREG(m) || S_ISDIR(m) || S_ISLNK(m) || S_ISCHR(m) ||
237 S_ISBLK(m) || S_ISFIFO(m) || S_ISSOCK(m);
238 }
239
240 /*
241 * Add a directory inode to a dentry, ensuring that no other dentry
242 * refers to this inode. Called with fc->inst_mutex.
243 */
fuse_d_add_directory(struct dentry * entry,struct inode * inode)244 static struct dentry *fuse_d_add_directory(struct dentry *entry,
245 struct inode *inode)
246 {
247 struct dentry *alias = d_find_alias(inode);
248 if (alias && !(alias->d_flags & DCACHE_DISCONNECTED)) {
249 /* This tries to shrink the subtree below alias */
250 fuse_invalidate_entry(alias);
251 dput(alias);
252 if (!list_empty(&inode->i_dentry))
253 return ERR_PTR(-EBUSY);
254 } else {
255 dput(alias);
256 }
257 return d_splice_alias(inode, entry);
258 }
259
fuse_lookup_name(struct super_block * sb,u64 nodeid,struct qstr * name,struct fuse_entry_out * outarg,struct inode ** inode)260 int fuse_lookup_name(struct super_block *sb, u64 nodeid, struct qstr *name,
261 struct fuse_entry_out *outarg, struct inode **inode)
262 {
263 struct fuse_conn *fc = get_fuse_conn_super(sb);
264 struct fuse_req *req;
265 struct fuse_forget_link *forget;
266 u64 attr_version;
267 int err;
268
269 *inode = NULL;
270 err = -ENAMETOOLONG;
271 if (name->len > FUSE_NAME_MAX)
272 goto out;
273
274 req = fuse_get_req(fc);
275 err = PTR_ERR(req);
276 if (IS_ERR(req))
277 goto out;
278
279 forget = fuse_alloc_forget();
280 err = -ENOMEM;
281 if (!forget) {
282 fuse_put_request(fc, req);
283 goto out;
284 }
285
286 attr_version = fuse_get_attr_version(fc);
287
288 fuse_lookup_init(fc, req, nodeid, name, outarg);
289 fuse_request_send(fc, req);
290 err = req->out.h.error;
291 fuse_put_request(fc, req);
292 /* Zero nodeid is same as -ENOENT, but with valid timeout */
293 if (err || !outarg->nodeid)
294 goto out_put_forget;
295
296 err = -EIO;
297 if (!outarg->nodeid)
298 goto out_put_forget;
299 if (!fuse_valid_type(outarg->attr.mode))
300 goto out_put_forget;
301
302 *inode = fuse_iget(sb, outarg->nodeid, outarg->generation,
303 &outarg->attr, entry_attr_timeout(outarg),
304 attr_version);
305 err = -ENOMEM;
306 if (!*inode) {
307 fuse_queue_forget(fc, forget, outarg->nodeid, 1);
308 goto out;
309 }
310 err = 0;
311
312 out_put_forget:
313 kfree(forget);
314 out:
315 return err;
316 }
317
fuse_lookup(struct inode * dir,struct dentry * entry,struct nameidata * nd)318 static struct dentry *fuse_lookup(struct inode *dir, struct dentry *entry,
319 struct nameidata *nd)
320 {
321 int err;
322 struct fuse_entry_out outarg;
323 struct inode *inode;
324 struct dentry *newent;
325 struct fuse_conn *fc = get_fuse_conn(dir);
326 bool outarg_valid = true;
327
328 err = fuse_lookup_name(dir->i_sb, get_node_id(dir), &entry->d_name,
329 &outarg, &inode);
330 if (err == -ENOENT) {
331 outarg_valid = false;
332 err = 0;
333 }
334 if (err)
335 goto out_err;
336
337 err = -EIO;
338 if (inode && get_node_id(inode) == FUSE_ROOT_ID)
339 goto out_iput;
340
341 if (inode && S_ISDIR(inode->i_mode)) {
342 mutex_lock(&fc->inst_mutex);
343 newent = fuse_d_add_directory(entry, inode);
344 mutex_unlock(&fc->inst_mutex);
345 err = PTR_ERR(newent);
346 if (IS_ERR(newent))
347 goto out_iput;
348 } else {
349 newent = d_splice_alias(inode, entry);
350 }
351
352 entry = newent ? newent : entry;
353 if (outarg_valid)
354 fuse_change_entry_timeout(entry, &outarg);
355 else
356 fuse_invalidate_entry_cache(entry);
357
358 return newent;
359
360 out_iput:
361 iput(inode);
362 out_err:
363 return ERR_PTR(err);
364 }
365
366 /*
367 * Atomic create+open operation
368 *
369 * If the filesystem doesn't support this, then fall back to separate
370 * 'mknod' + 'open' requests.
371 */
fuse_create_open(struct inode * dir,struct dentry * entry,umode_t mode,struct nameidata * nd)372 static int fuse_create_open(struct inode *dir, struct dentry *entry,
373 umode_t mode, struct nameidata *nd)
374 {
375 int err;
376 struct inode *inode;
377 struct fuse_conn *fc = get_fuse_conn(dir);
378 struct fuse_req *req;
379 struct fuse_forget_link *forget;
380 struct fuse_create_in inarg;
381 struct fuse_open_out outopen;
382 struct fuse_entry_out outentry;
383 struct fuse_file *ff;
384 struct file *file;
385 int flags = nd->intent.open.flags;
386
387 if (fc->no_create)
388 return -ENOSYS;
389
390 forget = fuse_alloc_forget();
391 if (!forget)
392 return -ENOMEM;
393
394 req = fuse_get_req(fc);
395 err = PTR_ERR(req);
396 if (IS_ERR(req))
397 goto out_put_forget_req;
398
399 err = -ENOMEM;
400 ff = fuse_file_alloc(fc);
401 if (!ff)
402 goto out_put_request;
403
404 if (!fc->dont_mask)
405 mode &= ~current_umask();
406
407 flags &= ~O_NOCTTY;
408 memset(&inarg, 0, sizeof(inarg));
409 memset(&outentry, 0, sizeof(outentry));
410 inarg.flags = flags;
411 inarg.mode = mode;
412 inarg.umask = current_umask();
413 req->in.h.opcode = FUSE_CREATE;
414 req->in.h.nodeid = get_node_id(dir);
415 req->in.numargs = 2;
416 req->in.args[0].size = fc->minor < 12 ? sizeof(struct fuse_open_in) :
417 sizeof(inarg);
418 req->in.args[0].value = &inarg;
419 req->in.args[1].size = entry->d_name.len + 1;
420 req->in.args[1].value = entry->d_name.name;
421 req->out.numargs = 2;
422 if (fc->minor < 9)
423 req->out.args[0].size = FUSE_COMPAT_ENTRY_OUT_SIZE;
424 else
425 req->out.args[0].size = sizeof(outentry);
426 req->out.args[0].value = &outentry;
427 req->out.args[1].size = sizeof(outopen);
428 req->out.args[1].value = &outopen;
429 fuse_request_send(fc, req);
430 err = req->out.h.error;
431 if (err) {
432 if (err == -ENOSYS)
433 fc->no_create = 1;
434 goto out_free_ff;
435 }
436
437 err = -EIO;
438 if (!S_ISREG(outentry.attr.mode) || invalid_nodeid(outentry.nodeid))
439 goto out_free_ff;
440
441 fuse_put_request(fc, req);
442 ff->fh = outopen.fh;
443 ff->nodeid = outentry.nodeid;
444 ff->open_flags = outopen.open_flags;
445 inode = fuse_iget(dir->i_sb, outentry.nodeid, outentry.generation,
446 &outentry.attr, entry_attr_timeout(&outentry), 0);
447 if (!inode) {
448 flags &= ~(O_CREAT | O_EXCL | O_TRUNC);
449 fuse_sync_release(ff, flags);
450 fuse_queue_forget(fc, forget, outentry.nodeid, 1);
451 return -ENOMEM;
452 }
453 kfree(forget);
454 d_instantiate(entry, inode);
455 fuse_change_entry_timeout(entry, &outentry);
456 fuse_invalidate_attr(dir);
457 file = lookup_instantiate_filp(nd, entry, generic_file_open);
458 if (IS_ERR(file)) {
459 fuse_sync_release(ff, flags);
460 return PTR_ERR(file);
461 }
462 file->private_data = fuse_file_get(ff);
463 fuse_finish_open(inode, file);
464 return 0;
465
466 out_free_ff:
467 fuse_file_free(ff);
468 out_put_request:
469 fuse_put_request(fc, req);
470 out_put_forget_req:
471 kfree(forget);
472 return err;
473 }
474
475 /*
476 * Code shared between mknod, mkdir, symlink and link
477 */
create_new_entry(struct fuse_conn * fc,struct fuse_req * req,struct inode * dir,struct dentry * entry,umode_t mode)478 static int create_new_entry(struct fuse_conn *fc, struct fuse_req *req,
479 struct inode *dir, struct dentry *entry,
480 umode_t mode)
481 {
482 struct fuse_entry_out outarg;
483 struct inode *inode;
484 int err;
485 struct fuse_forget_link *forget;
486
487 forget = fuse_alloc_forget();
488 if (!forget) {
489 fuse_put_request(fc, req);
490 return -ENOMEM;
491 }
492
493 memset(&outarg, 0, sizeof(outarg));
494 req->in.h.nodeid = get_node_id(dir);
495 req->out.numargs = 1;
496 if (fc->minor < 9)
497 req->out.args[0].size = FUSE_COMPAT_ENTRY_OUT_SIZE;
498 else
499 req->out.args[0].size = sizeof(outarg);
500 req->out.args[0].value = &outarg;
501 fuse_request_send(fc, req);
502 err = req->out.h.error;
503 fuse_put_request(fc, req);
504 if (err)
505 goto out_put_forget_req;
506
507 err = -EIO;
508 if (invalid_nodeid(outarg.nodeid))
509 goto out_put_forget_req;
510
511 if ((outarg.attr.mode ^ mode) & S_IFMT)
512 goto out_put_forget_req;
513
514 inode = fuse_iget(dir->i_sb, outarg.nodeid, outarg.generation,
515 &outarg.attr, entry_attr_timeout(&outarg), 0);
516 if (!inode) {
517 fuse_queue_forget(fc, forget, outarg.nodeid, 1);
518 return -ENOMEM;
519 }
520 kfree(forget);
521
522 if (S_ISDIR(inode->i_mode)) {
523 struct dentry *alias;
524 mutex_lock(&fc->inst_mutex);
525 alias = d_find_alias(inode);
526 if (alias) {
527 /* New directory must have moved since mkdir */
528 mutex_unlock(&fc->inst_mutex);
529 dput(alias);
530 iput(inode);
531 return -EBUSY;
532 }
533 d_instantiate(entry, inode);
534 mutex_unlock(&fc->inst_mutex);
535 } else
536 d_instantiate(entry, inode);
537
538 fuse_change_entry_timeout(entry, &outarg);
539 fuse_invalidate_attr(dir);
540 return 0;
541
542 out_put_forget_req:
543 kfree(forget);
544 return err;
545 }
546
fuse_mknod(struct inode * dir,struct dentry * entry,umode_t mode,dev_t rdev)547 static int fuse_mknod(struct inode *dir, struct dentry *entry, umode_t mode,
548 dev_t rdev)
549 {
550 struct fuse_mknod_in inarg;
551 struct fuse_conn *fc = get_fuse_conn(dir);
552 struct fuse_req *req = fuse_get_req(fc);
553 if (IS_ERR(req))
554 return PTR_ERR(req);
555
556 if (!fc->dont_mask)
557 mode &= ~current_umask();
558
559 memset(&inarg, 0, sizeof(inarg));
560 inarg.mode = mode;
561 inarg.rdev = new_encode_dev(rdev);
562 inarg.umask = current_umask();
563 req->in.h.opcode = FUSE_MKNOD;
564 req->in.numargs = 2;
565 req->in.args[0].size = fc->minor < 12 ? FUSE_COMPAT_MKNOD_IN_SIZE :
566 sizeof(inarg);
567 req->in.args[0].value = &inarg;
568 req->in.args[1].size = entry->d_name.len + 1;
569 req->in.args[1].value = entry->d_name.name;
570 return create_new_entry(fc, req, dir, entry, mode);
571 }
572
fuse_create(struct inode * dir,struct dentry * entry,umode_t mode,struct nameidata * nd)573 static int fuse_create(struct inode *dir, struct dentry *entry, umode_t mode,
574 struct nameidata *nd)
575 {
576 if (nd) {
577 int err = fuse_create_open(dir, entry, mode, nd);
578 if (err != -ENOSYS)
579 return err;
580 /* Fall back on mknod */
581 }
582 return fuse_mknod(dir, entry, mode, 0);
583 }
584
fuse_mkdir(struct inode * dir,struct dentry * entry,umode_t mode)585 static int fuse_mkdir(struct inode *dir, struct dentry *entry, umode_t mode)
586 {
587 struct fuse_mkdir_in inarg;
588 struct fuse_conn *fc = get_fuse_conn(dir);
589 struct fuse_req *req = fuse_get_req(fc);
590 if (IS_ERR(req))
591 return PTR_ERR(req);
592
593 if (!fc->dont_mask)
594 mode &= ~current_umask();
595
596 memset(&inarg, 0, sizeof(inarg));
597 inarg.mode = mode;
598 inarg.umask = current_umask();
599 req->in.h.opcode = FUSE_MKDIR;
600 req->in.numargs = 2;
601 req->in.args[0].size = sizeof(inarg);
602 req->in.args[0].value = &inarg;
603 req->in.args[1].size = entry->d_name.len + 1;
604 req->in.args[1].value = entry->d_name.name;
605 return create_new_entry(fc, req, dir, entry, S_IFDIR);
606 }
607
fuse_symlink(struct inode * dir,struct dentry * entry,const char * link)608 static int fuse_symlink(struct inode *dir, struct dentry *entry,
609 const char *link)
610 {
611 struct fuse_conn *fc = get_fuse_conn(dir);
612 unsigned len = strlen(link) + 1;
613 struct fuse_req *req = fuse_get_req(fc);
614 if (IS_ERR(req))
615 return PTR_ERR(req);
616
617 req->in.h.opcode = FUSE_SYMLINK;
618 req->in.numargs = 2;
619 req->in.args[0].size = entry->d_name.len + 1;
620 req->in.args[0].value = entry->d_name.name;
621 req->in.args[1].size = len;
622 req->in.args[1].value = link;
623 return create_new_entry(fc, req, dir, entry, S_IFLNK);
624 }
625
fuse_unlink(struct inode * dir,struct dentry * entry)626 static int fuse_unlink(struct inode *dir, struct dentry *entry)
627 {
628 int err;
629 struct fuse_conn *fc = get_fuse_conn(dir);
630 struct fuse_req *req = fuse_get_req(fc);
631 if (IS_ERR(req))
632 return PTR_ERR(req);
633
634 req->in.h.opcode = FUSE_UNLINK;
635 req->in.h.nodeid = get_node_id(dir);
636 req->in.numargs = 1;
637 req->in.args[0].size = entry->d_name.len + 1;
638 req->in.args[0].value = entry->d_name.name;
639 fuse_request_send(fc, req);
640 err = req->out.h.error;
641 fuse_put_request(fc, req);
642 if (!err) {
643 struct inode *inode = entry->d_inode;
644 struct fuse_inode *fi = get_fuse_inode(inode);
645
646 spin_lock(&fc->lock);
647 fi->attr_version = ++fc->attr_version;
648 /*
649 * If i_nlink == 0 then unlink doesn't make sense, yet this can
650 * happen if userspace filesystem is careless. It would be
651 * difficult to enforce correct nlink usage so just ignore this
652 * condition here
653 */
654 if (inode->i_nlink > 0)
655 drop_nlink(inode);
656 spin_unlock(&fc->lock);
657 fuse_invalidate_attr(inode);
658 fuse_invalidate_attr(dir);
659 fuse_invalidate_entry_cache(entry);
660 } else if (err == -EINTR)
661 fuse_invalidate_entry(entry);
662 return err;
663 }
664
fuse_rmdir(struct inode * dir,struct dentry * entry)665 static int fuse_rmdir(struct inode *dir, struct dentry *entry)
666 {
667 int err;
668 struct fuse_conn *fc = get_fuse_conn(dir);
669 struct fuse_req *req = fuse_get_req(fc);
670 if (IS_ERR(req))
671 return PTR_ERR(req);
672
673 req->in.h.opcode = FUSE_RMDIR;
674 req->in.h.nodeid = get_node_id(dir);
675 req->in.numargs = 1;
676 req->in.args[0].size = entry->d_name.len + 1;
677 req->in.args[0].value = entry->d_name.name;
678 fuse_request_send(fc, req);
679 err = req->out.h.error;
680 fuse_put_request(fc, req);
681 if (!err) {
682 clear_nlink(entry->d_inode);
683 fuse_invalidate_attr(dir);
684 fuse_invalidate_entry_cache(entry);
685 } else if (err == -EINTR)
686 fuse_invalidate_entry(entry);
687 return err;
688 }
689
fuse_rename(struct inode * olddir,struct dentry * oldent,struct inode * newdir,struct dentry * newent)690 static int fuse_rename(struct inode *olddir, struct dentry *oldent,
691 struct inode *newdir, struct dentry *newent)
692 {
693 int err;
694 struct fuse_rename_in inarg;
695 struct fuse_conn *fc = get_fuse_conn(olddir);
696 struct fuse_req *req = fuse_get_req(fc);
697
698 if (IS_ERR(req))
699 return PTR_ERR(req);
700
701 memset(&inarg, 0, sizeof(inarg));
702 inarg.newdir = get_node_id(newdir);
703 req->in.h.opcode = FUSE_RENAME;
704 req->in.h.nodeid = get_node_id(olddir);
705 req->in.numargs = 3;
706 req->in.args[0].size = sizeof(inarg);
707 req->in.args[0].value = &inarg;
708 req->in.args[1].size = oldent->d_name.len + 1;
709 req->in.args[1].value = oldent->d_name.name;
710 req->in.args[2].size = newent->d_name.len + 1;
711 req->in.args[2].value = newent->d_name.name;
712 fuse_request_send(fc, req);
713 err = req->out.h.error;
714 fuse_put_request(fc, req);
715 if (!err) {
716 /* ctime changes */
717 fuse_invalidate_attr(oldent->d_inode);
718
719 fuse_invalidate_attr(olddir);
720 if (olddir != newdir)
721 fuse_invalidate_attr(newdir);
722
723 /* newent will end up negative */
724 if (newent->d_inode) {
725 fuse_invalidate_attr(newent->d_inode);
726 fuse_invalidate_entry_cache(newent);
727 }
728 } else if (err == -EINTR) {
729 /* If request was interrupted, DEITY only knows if the
730 rename actually took place. If the invalidation
731 fails (e.g. some process has CWD under the renamed
732 directory), then there can be inconsistency between
733 the dcache and the real filesystem. Tough luck. */
734 fuse_invalidate_entry(oldent);
735 if (newent->d_inode)
736 fuse_invalidate_entry(newent);
737 }
738
739 return err;
740 }
741
fuse_link(struct dentry * entry,struct inode * newdir,struct dentry * newent)742 static int fuse_link(struct dentry *entry, struct inode *newdir,
743 struct dentry *newent)
744 {
745 int err;
746 struct fuse_link_in inarg;
747 struct inode *inode = entry->d_inode;
748 struct fuse_conn *fc = get_fuse_conn(inode);
749 struct fuse_req *req = fuse_get_req(fc);
750 if (IS_ERR(req))
751 return PTR_ERR(req);
752
753 memset(&inarg, 0, sizeof(inarg));
754 inarg.oldnodeid = get_node_id(inode);
755 req->in.h.opcode = FUSE_LINK;
756 req->in.numargs = 2;
757 req->in.args[0].size = sizeof(inarg);
758 req->in.args[0].value = &inarg;
759 req->in.args[1].size = newent->d_name.len + 1;
760 req->in.args[1].value = newent->d_name.name;
761 err = create_new_entry(fc, req, newdir, newent, inode->i_mode);
762 /* Contrary to "normal" filesystems it can happen that link
763 makes two "logical" inodes point to the same "physical"
764 inode. We invalidate the attributes of the old one, so it
765 will reflect changes in the backing inode (link count,
766 etc.)
767 */
768 if (!err) {
769 struct fuse_inode *fi = get_fuse_inode(inode);
770
771 spin_lock(&fc->lock);
772 fi->attr_version = ++fc->attr_version;
773 inc_nlink(inode);
774 spin_unlock(&fc->lock);
775 fuse_invalidate_attr(inode);
776 } else if (err == -EINTR) {
777 fuse_invalidate_attr(inode);
778 }
779 return err;
780 }
781
fuse_fillattr(struct inode * inode,struct fuse_attr * attr,struct kstat * stat)782 static void fuse_fillattr(struct inode *inode, struct fuse_attr *attr,
783 struct kstat *stat)
784 {
785 stat->dev = inode->i_sb->s_dev;
786 stat->ino = attr->ino;
787 stat->mode = (inode->i_mode & S_IFMT) | (attr->mode & 07777);
788 stat->nlink = attr->nlink;
789 stat->uid = attr->uid;
790 stat->gid = attr->gid;
791 stat->rdev = inode->i_rdev;
792 stat->atime.tv_sec = attr->atime;
793 stat->atime.tv_nsec = attr->atimensec;
794 stat->mtime.tv_sec = attr->mtime;
795 stat->mtime.tv_nsec = attr->mtimensec;
796 stat->ctime.tv_sec = attr->ctime;
797 stat->ctime.tv_nsec = attr->ctimensec;
798 stat->size = attr->size;
799 stat->blocks = attr->blocks;
800 stat->blksize = (1 << inode->i_blkbits);
801 }
802
fuse_do_getattr(struct inode * inode,struct kstat * stat,struct file * file)803 static int fuse_do_getattr(struct inode *inode, struct kstat *stat,
804 struct file *file)
805 {
806 int err;
807 struct fuse_getattr_in inarg;
808 struct fuse_attr_out outarg;
809 struct fuse_conn *fc = get_fuse_conn(inode);
810 struct fuse_req *req;
811 u64 attr_version;
812
813 req = fuse_get_req(fc);
814 if (IS_ERR(req))
815 return PTR_ERR(req);
816
817 attr_version = fuse_get_attr_version(fc);
818
819 memset(&inarg, 0, sizeof(inarg));
820 memset(&outarg, 0, sizeof(outarg));
821 /* Directories have separate file-handle space */
822 if (file && S_ISREG(inode->i_mode)) {
823 struct fuse_file *ff = file->private_data;
824
825 inarg.getattr_flags |= FUSE_GETATTR_FH;
826 inarg.fh = ff->fh;
827 }
828 req->in.h.opcode = FUSE_GETATTR;
829 req->in.h.nodeid = get_node_id(inode);
830 req->in.numargs = 1;
831 req->in.args[0].size = sizeof(inarg);
832 req->in.args[0].value = &inarg;
833 req->out.numargs = 1;
834 if (fc->minor < 9)
835 req->out.args[0].size = FUSE_COMPAT_ATTR_OUT_SIZE;
836 else
837 req->out.args[0].size = sizeof(outarg);
838 req->out.args[0].value = &outarg;
839 fuse_request_send(fc, req);
840 err = req->out.h.error;
841 fuse_put_request(fc, req);
842 if (!err) {
843 if ((inode->i_mode ^ outarg.attr.mode) & S_IFMT) {
844 make_bad_inode(inode);
845 err = -EIO;
846 } else {
847 fuse_change_attributes(inode, &outarg.attr,
848 attr_timeout(&outarg),
849 attr_version);
850 if (stat)
851 fuse_fillattr(inode, &outarg.attr, stat);
852 }
853 }
854 return err;
855 }
856
fuse_update_attributes(struct inode * inode,struct kstat * stat,struct file * file,bool * refreshed)857 int fuse_update_attributes(struct inode *inode, struct kstat *stat,
858 struct file *file, bool *refreshed)
859 {
860 struct fuse_inode *fi = get_fuse_inode(inode);
861 int err;
862 bool r;
863
864 if (fi->i_time < get_jiffies_64()) {
865 r = true;
866 err = fuse_do_getattr(inode, stat, file);
867 } else {
868 r = false;
869 err = 0;
870 if (stat) {
871 generic_fillattr(inode, stat);
872 stat->mode = fi->orig_i_mode;
873 stat->ino = fi->orig_ino;
874 }
875 }
876
877 if (refreshed != NULL)
878 *refreshed = r;
879
880 return err;
881 }
882
fuse_reverse_inval_entry(struct super_block * sb,u64 parent_nodeid,u64 child_nodeid,struct qstr * name)883 int fuse_reverse_inval_entry(struct super_block *sb, u64 parent_nodeid,
884 u64 child_nodeid, struct qstr *name)
885 {
886 int err = -ENOTDIR;
887 struct inode *parent;
888 struct dentry *dir;
889 struct dentry *entry;
890
891 parent = ilookup5(sb, parent_nodeid, fuse_inode_eq, &parent_nodeid);
892 if (!parent)
893 return -ENOENT;
894
895 mutex_lock(&parent->i_mutex);
896 if (!S_ISDIR(parent->i_mode))
897 goto unlock;
898
899 err = -ENOENT;
900 dir = d_find_alias(parent);
901 if (!dir)
902 goto unlock;
903
904 entry = d_lookup(dir, name);
905 dput(dir);
906 if (!entry)
907 goto unlock;
908
909 fuse_invalidate_attr(parent);
910 fuse_invalidate_entry(entry);
911
912 if (child_nodeid != 0 && entry->d_inode) {
913 mutex_lock(&entry->d_inode->i_mutex);
914 if (get_node_id(entry->d_inode) != child_nodeid) {
915 err = -ENOENT;
916 goto badentry;
917 }
918 if (d_mountpoint(entry)) {
919 err = -EBUSY;
920 goto badentry;
921 }
922 if (S_ISDIR(entry->d_inode->i_mode)) {
923 shrink_dcache_parent(entry);
924 if (!simple_empty(entry)) {
925 err = -ENOTEMPTY;
926 goto badentry;
927 }
928 entry->d_inode->i_flags |= S_DEAD;
929 }
930 dont_mount(entry);
931 clear_nlink(entry->d_inode);
932 err = 0;
933 badentry:
934 mutex_unlock(&entry->d_inode->i_mutex);
935 if (!err)
936 d_delete(entry);
937 } else {
938 err = 0;
939 }
940 dput(entry);
941
942 unlock:
943 mutex_unlock(&parent->i_mutex);
944 iput(parent);
945 return err;
946 }
947
948 /*
949 * Calling into a user-controlled filesystem gives the filesystem
950 * daemon ptrace-like capabilities over the requester process. This
951 * means, that the filesystem daemon is able to record the exact
952 * filesystem operations performed, and can also control the behavior
953 * of the requester process in otherwise impossible ways. For example
954 * it can delay the operation for arbitrary length of time allowing
955 * DoS against the requester.
956 *
957 * For this reason only those processes can call into the filesystem,
958 * for which the owner of the mount has ptrace privilege. This
959 * excludes processes started by other users, suid or sgid processes.
960 */
fuse_allow_task(struct fuse_conn * fc,struct task_struct * task)961 int fuse_allow_task(struct fuse_conn *fc, struct task_struct *task)
962 {
963 const struct cred *cred;
964 int ret;
965
966 if (fc->flags & FUSE_ALLOW_OTHER)
967 return 1;
968
969 rcu_read_lock();
970 ret = 0;
971 cred = __task_cred(task);
972 if (cred->euid == fc->user_id &&
973 cred->suid == fc->user_id &&
974 cred->uid == fc->user_id &&
975 cred->egid == fc->group_id &&
976 cred->sgid == fc->group_id &&
977 cred->gid == fc->group_id)
978 ret = 1;
979 rcu_read_unlock();
980
981 return ret;
982 }
983
fuse_access(struct inode * inode,int mask)984 static int fuse_access(struct inode *inode, int mask)
985 {
986 struct fuse_conn *fc = get_fuse_conn(inode);
987 struct fuse_req *req;
988 struct fuse_access_in inarg;
989 int err;
990
991 if (fc->no_access)
992 return 0;
993
994 req = fuse_get_req(fc);
995 if (IS_ERR(req))
996 return PTR_ERR(req);
997
998 memset(&inarg, 0, sizeof(inarg));
999 inarg.mask = mask & (MAY_READ | MAY_WRITE | MAY_EXEC);
1000 req->in.h.opcode = FUSE_ACCESS;
1001 req->in.h.nodeid = get_node_id(inode);
1002 req->in.numargs = 1;
1003 req->in.args[0].size = sizeof(inarg);
1004 req->in.args[0].value = &inarg;
1005 fuse_request_send(fc, req);
1006 err = req->out.h.error;
1007 fuse_put_request(fc, req);
1008 if (err == -ENOSYS) {
1009 fc->no_access = 1;
1010 err = 0;
1011 }
1012 return err;
1013 }
1014
fuse_perm_getattr(struct inode * inode,int mask)1015 static int fuse_perm_getattr(struct inode *inode, int mask)
1016 {
1017 if (mask & MAY_NOT_BLOCK)
1018 return -ECHILD;
1019
1020 return fuse_do_getattr(inode, NULL, NULL);
1021 }
1022
1023 /*
1024 * Check permission. The two basic access models of FUSE are:
1025 *
1026 * 1) Local access checking ('default_permissions' mount option) based
1027 * on file mode. This is the plain old disk filesystem permission
1028 * modell.
1029 *
1030 * 2) "Remote" access checking, where server is responsible for
1031 * checking permission in each inode operation. An exception to this
1032 * is if ->permission() was invoked from sys_access() in which case an
1033 * access request is sent. Execute permission is still checked
1034 * locally based on file mode.
1035 */
fuse_permission(struct inode * inode,int mask)1036 static int fuse_permission(struct inode *inode, int mask)
1037 {
1038 struct fuse_conn *fc = get_fuse_conn(inode);
1039 bool refreshed = false;
1040 int err = 0;
1041
1042 if (!fuse_allow_task(fc, current))
1043 return -EACCES;
1044
1045 /*
1046 * If attributes are needed, refresh them before proceeding
1047 */
1048 if ((fc->flags & FUSE_DEFAULT_PERMISSIONS) ||
1049 ((mask & MAY_EXEC) && S_ISREG(inode->i_mode))) {
1050 struct fuse_inode *fi = get_fuse_inode(inode);
1051
1052 if (fi->i_time < get_jiffies_64()) {
1053 refreshed = true;
1054
1055 err = fuse_perm_getattr(inode, mask);
1056 if (err)
1057 return err;
1058 }
1059 }
1060
1061 if (fc->flags & FUSE_DEFAULT_PERMISSIONS) {
1062 err = generic_permission(inode, mask);
1063
1064 /* If permission is denied, try to refresh file
1065 attributes. This is also needed, because the root
1066 node will at first have no permissions */
1067 if (err == -EACCES && !refreshed) {
1068 err = fuse_perm_getattr(inode, mask);
1069 if (!err)
1070 err = generic_permission(inode, mask);
1071 }
1072
1073 /* Note: the opposite of the above test does not
1074 exist. So if permissions are revoked this won't be
1075 noticed immediately, only after the attribute
1076 timeout has expired */
1077 } else if (mask & (MAY_ACCESS | MAY_CHDIR)) {
1078 if (mask & MAY_NOT_BLOCK)
1079 return -ECHILD;
1080
1081 err = fuse_access(inode, mask);
1082 } else if ((mask & MAY_EXEC) && S_ISREG(inode->i_mode)) {
1083 if (!(inode->i_mode & S_IXUGO)) {
1084 if (refreshed)
1085 return -EACCES;
1086
1087 err = fuse_perm_getattr(inode, mask);
1088 if (!err && !(inode->i_mode & S_IXUGO))
1089 return -EACCES;
1090 }
1091 }
1092 return err;
1093 }
1094
parse_dirfile(char * buf,size_t nbytes,struct file * file,void * dstbuf,filldir_t filldir)1095 static int parse_dirfile(char *buf, size_t nbytes, struct file *file,
1096 void *dstbuf, filldir_t filldir)
1097 {
1098 while (nbytes >= FUSE_NAME_OFFSET) {
1099 struct fuse_dirent *dirent = (struct fuse_dirent *) buf;
1100 size_t reclen = FUSE_DIRENT_SIZE(dirent);
1101 int over;
1102 if (!dirent->namelen || dirent->namelen > FUSE_NAME_MAX)
1103 return -EIO;
1104 if (reclen > nbytes)
1105 break;
1106 if (memchr(dirent->name, '/', dirent->namelen) != NULL)
1107 return -EIO;
1108
1109 over = filldir(dstbuf, dirent->name, dirent->namelen,
1110 file->f_pos, dirent->ino, dirent->type);
1111 if (over)
1112 break;
1113
1114 buf += reclen;
1115 nbytes -= reclen;
1116 file->f_pos = dirent->off;
1117 }
1118
1119 return 0;
1120 }
1121
fuse_readdir(struct file * file,void * dstbuf,filldir_t filldir)1122 static int fuse_readdir(struct file *file, void *dstbuf, filldir_t filldir)
1123 {
1124 int err;
1125 size_t nbytes;
1126 struct page *page;
1127 struct inode *inode = file->f_path.dentry->d_inode;
1128 struct fuse_conn *fc = get_fuse_conn(inode);
1129 struct fuse_req *req;
1130
1131 if (is_bad_inode(inode))
1132 return -EIO;
1133
1134 req = fuse_get_req(fc);
1135 if (IS_ERR(req))
1136 return PTR_ERR(req);
1137
1138 page = alloc_page(GFP_KERNEL);
1139 if (!page) {
1140 fuse_put_request(fc, req);
1141 return -ENOMEM;
1142 }
1143 req->out.argpages = 1;
1144 req->num_pages = 1;
1145 req->pages[0] = page;
1146 fuse_read_fill(req, file, file->f_pos, PAGE_SIZE, FUSE_READDIR);
1147 fuse_request_send(fc, req);
1148 nbytes = req->out.args[0].size;
1149 err = req->out.h.error;
1150 fuse_put_request(fc, req);
1151 if (!err)
1152 err = parse_dirfile(page_address(page), nbytes, file, dstbuf,
1153 filldir);
1154
1155 __free_page(page);
1156 fuse_invalidate_attr(inode); /* atime changed */
1157 return err;
1158 }
1159
read_link(struct dentry * dentry)1160 static char *read_link(struct dentry *dentry)
1161 {
1162 struct inode *inode = dentry->d_inode;
1163 struct fuse_conn *fc = get_fuse_conn(inode);
1164 struct fuse_req *req = fuse_get_req(fc);
1165 char *link;
1166
1167 if (IS_ERR(req))
1168 return ERR_CAST(req);
1169
1170 link = (char *) __get_free_page(GFP_KERNEL);
1171 if (!link) {
1172 link = ERR_PTR(-ENOMEM);
1173 goto out;
1174 }
1175 req->in.h.opcode = FUSE_READLINK;
1176 req->in.h.nodeid = get_node_id(inode);
1177 req->out.argvar = 1;
1178 req->out.numargs = 1;
1179 req->out.args[0].size = PAGE_SIZE - 1;
1180 req->out.args[0].value = link;
1181 fuse_request_send(fc, req);
1182 if (req->out.h.error) {
1183 free_page((unsigned long) link);
1184 link = ERR_PTR(req->out.h.error);
1185 } else
1186 link[req->out.args[0].size] = '\0';
1187 out:
1188 fuse_put_request(fc, req);
1189 fuse_invalidate_attr(inode); /* atime changed */
1190 return link;
1191 }
1192
free_link(char * link)1193 static void free_link(char *link)
1194 {
1195 if (!IS_ERR(link))
1196 free_page((unsigned long) link);
1197 }
1198
fuse_follow_link(struct dentry * dentry,struct nameidata * nd)1199 static void *fuse_follow_link(struct dentry *dentry, struct nameidata *nd)
1200 {
1201 nd_set_link(nd, read_link(dentry));
1202 return NULL;
1203 }
1204
fuse_put_link(struct dentry * dentry,struct nameidata * nd,void * c)1205 static void fuse_put_link(struct dentry *dentry, struct nameidata *nd, void *c)
1206 {
1207 free_link(nd_get_link(nd));
1208 }
1209
fuse_dir_open(struct inode * inode,struct file * file)1210 static int fuse_dir_open(struct inode *inode, struct file *file)
1211 {
1212 return fuse_open_common(inode, file, true);
1213 }
1214
fuse_dir_release(struct inode * inode,struct file * file)1215 static int fuse_dir_release(struct inode *inode, struct file *file)
1216 {
1217 fuse_release_common(file, FUSE_RELEASEDIR);
1218
1219 return 0;
1220 }
1221
fuse_dir_fsync(struct file * file,loff_t start,loff_t end,int datasync)1222 static int fuse_dir_fsync(struct file *file, loff_t start, loff_t end,
1223 int datasync)
1224 {
1225 return fuse_fsync_common(file, start, end, datasync, 1);
1226 }
1227
fuse_dir_ioctl(struct file * file,unsigned int cmd,unsigned long arg)1228 static long fuse_dir_ioctl(struct file *file, unsigned int cmd,
1229 unsigned long arg)
1230 {
1231 struct fuse_conn *fc = get_fuse_conn(file->f_mapping->host);
1232
1233 /* FUSE_IOCTL_DIR only supported for API version >= 7.18 */
1234 if (fc->minor < 18)
1235 return -ENOTTY;
1236
1237 return fuse_ioctl_common(file, cmd, arg, FUSE_IOCTL_DIR);
1238 }
1239
fuse_dir_compat_ioctl(struct file * file,unsigned int cmd,unsigned long arg)1240 static long fuse_dir_compat_ioctl(struct file *file, unsigned int cmd,
1241 unsigned long arg)
1242 {
1243 struct fuse_conn *fc = get_fuse_conn(file->f_mapping->host);
1244
1245 if (fc->minor < 18)
1246 return -ENOTTY;
1247
1248 return fuse_ioctl_common(file, cmd, arg,
1249 FUSE_IOCTL_COMPAT | FUSE_IOCTL_DIR);
1250 }
1251
update_mtime(unsigned ivalid)1252 static bool update_mtime(unsigned ivalid)
1253 {
1254 /* Always update if mtime is explicitly set */
1255 if (ivalid & ATTR_MTIME_SET)
1256 return true;
1257
1258 /* If it's an open(O_TRUNC) or an ftruncate(), don't update */
1259 if ((ivalid & ATTR_SIZE) && (ivalid & (ATTR_OPEN | ATTR_FILE)))
1260 return false;
1261
1262 /* In all other cases update */
1263 return true;
1264 }
1265
iattr_to_fattr(struct iattr * iattr,struct fuse_setattr_in * arg)1266 static void iattr_to_fattr(struct iattr *iattr, struct fuse_setattr_in *arg)
1267 {
1268 unsigned ivalid = iattr->ia_valid;
1269
1270 if (ivalid & ATTR_MODE)
1271 arg->valid |= FATTR_MODE, arg->mode = iattr->ia_mode;
1272 if (ivalid & ATTR_UID)
1273 arg->valid |= FATTR_UID, arg->uid = iattr->ia_uid;
1274 if (ivalid & ATTR_GID)
1275 arg->valid |= FATTR_GID, arg->gid = iattr->ia_gid;
1276 if (ivalid & ATTR_SIZE)
1277 arg->valid |= FATTR_SIZE, arg->size = iattr->ia_size;
1278 if (ivalid & ATTR_ATIME) {
1279 arg->valid |= FATTR_ATIME;
1280 arg->atime = iattr->ia_atime.tv_sec;
1281 arg->atimensec = iattr->ia_atime.tv_nsec;
1282 if (!(ivalid & ATTR_ATIME_SET))
1283 arg->valid |= FATTR_ATIME_NOW;
1284 }
1285 if ((ivalid & ATTR_MTIME) && update_mtime(ivalid)) {
1286 arg->valid |= FATTR_MTIME;
1287 arg->mtime = iattr->ia_mtime.tv_sec;
1288 arg->mtimensec = iattr->ia_mtime.tv_nsec;
1289 if (!(ivalid & ATTR_MTIME_SET))
1290 arg->valid |= FATTR_MTIME_NOW;
1291 }
1292 }
1293
1294 /*
1295 * Prevent concurrent writepages on inode
1296 *
1297 * This is done by adding a negative bias to the inode write counter
1298 * and waiting for all pending writes to finish.
1299 */
fuse_set_nowrite(struct inode * inode)1300 void fuse_set_nowrite(struct inode *inode)
1301 {
1302 struct fuse_conn *fc = get_fuse_conn(inode);
1303 struct fuse_inode *fi = get_fuse_inode(inode);
1304
1305 BUG_ON(!mutex_is_locked(&inode->i_mutex));
1306
1307 spin_lock(&fc->lock);
1308 BUG_ON(fi->writectr < 0);
1309 fi->writectr += FUSE_NOWRITE;
1310 spin_unlock(&fc->lock);
1311 wait_event(fi->page_waitq, fi->writectr == FUSE_NOWRITE);
1312 }
1313
1314 /*
1315 * Allow writepages on inode
1316 *
1317 * Remove the bias from the writecounter and send any queued
1318 * writepages.
1319 */
__fuse_release_nowrite(struct inode * inode)1320 static void __fuse_release_nowrite(struct inode *inode)
1321 {
1322 struct fuse_inode *fi = get_fuse_inode(inode);
1323
1324 BUG_ON(fi->writectr != FUSE_NOWRITE);
1325 fi->writectr = 0;
1326 fuse_flush_writepages(inode);
1327 }
1328
fuse_release_nowrite(struct inode * inode)1329 void fuse_release_nowrite(struct inode *inode)
1330 {
1331 struct fuse_conn *fc = get_fuse_conn(inode);
1332
1333 spin_lock(&fc->lock);
1334 __fuse_release_nowrite(inode);
1335 spin_unlock(&fc->lock);
1336 }
1337
1338 /*
1339 * Set attributes, and at the same time refresh them.
1340 *
1341 * Truncation is slightly complicated, because the 'truncate' request
1342 * may fail, in which case we don't want to touch the mapping.
1343 * vmtruncate() doesn't allow for this case, so do the rlimit checking
1344 * and the actual truncation by hand.
1345 */
fuse_do_setattr(struct dentry * entry,struct iattr * attr,struct file * file)1346 static int fuse_do_setattr(struct dentry *entry, struct iattr *attr,
1347 struct file *file)
1348 {
1349 struct inode *inode = entry->d_inode;
1350 struct fuse_conn *fc = get_fuse_conn(inode);
1351 struct fuse_inode *fi = get_fuse_inode(inode);
1352 struct fuse_req *req;
1353 struct fuse_setattr_in inarg;
1354 struct fuse_attr_out outarg;
1355 bool is_truncate = false;
1356 loff_t oldsize;
1357 int err;
1358
1359 if (!fuse_allow_task(fc, current))
1360 return -EACCES;
1361
1362 if (!(fc->flags & FUSE_DEFAULT_PERMISSIONS))
1363 attr->ia_valid |= ATTR_FORCE;
1364
1365 err = inode_change_ok(inode, attr);
1366 if (err)
1367 return err;
1368
1369 if (attr->ia_valid & ATTR_OPEN) {
1370 if (fc->atomic_o_trunc)
1371 return 0;
1372 file = NULL;
1373 }
1374
1375 if (attr->ia_valid & ATTR_SIZE)
1376 is_truncate = true;
1377
1378 req = fuse_get_req(fc);
1379 if (IS_ERR(req))
1380 return PTR_ERR(req);
1381
1382 if (is_truncate) {
1383 fuse_set_nowrite(inode);
1384 set_bit(FUSE_I_SIZE_UNSTABLE, &fi->state);
1385 }
1386
1387 memset(&inarg, 0, sizeof(inarg));
1388 memset(&outarg, 0, sizeof(outarg));
1389 iattr_to_fattr(attr, &inarg);
1390 if (file) {
1391 struct fuse_file *ff = file->private_data;
1392 inarg.valid |= FATTR_FH;
1393 inarg.fh = ff->fh;
1394 }
1395 if (attr->ia_valid & ATTR_SIZE) {
1396 /* For mandatory locking in truncate */
1397 inarg.valid |= FATTR_LOCKOWNER;
1398 inarg.lock_owner = fuse_lock_owner_id(fc, current->files);
1399 }
1400 req->in.h.opcode = FUSE_SETATTR;
1401 req->in.h.nodeid = get_node_id(inode);
1402 req->in.numargs = 1;
1403 req->in.args[0].size = sizeof(inarg);
1404 req->in.args[0].value = &inarg;
1405 req->out.numargs = 1;
1406 if (fc->minor < 9)
1407 req->out.args[0].size = FUSE_COMPAT_ATTR_OUT_SIZE;
1408 else
1409 req->out.args[0].size = sizeof(outarg);
1410 req->out.args[0].value = &outarg;
1411 fuse_request_send(fc, req);
1412 err = req->out.h.error;
1413 fuse_put_request(fc, req);
1414 if (err) {
1415 if (err == -EINTR)
1416 fuse_invalidate_attr(inode);
1417 goto error;
1418 }
1419
1420 if ((inode->i_mode ^ outarg.attr.mode) & S_IFMT) {
1421 make_bad_inode(inode);
1422 err = -EIO;
1423 goto error;
1424 }
1425
1426 spin_lock(&fc->lock);
1427 fuse_change_attributes_common(inode, &outarg.attr,
1428 attr_timeout(&outarg));
1429 oldsize = inode->i_size;
1430 i_size_write(inode, outarg.attr.size);
1431
1432 if (is_truncate) {
1433 /* NOTE: this may release/reacquire fc->lock */
1434 __fuse_release_nowrite(inode);
1435 }
1436 spin_unlock(&fc->lock);
1437
1438 /*
1439 * Only call invalidate_inode_pages2() after removing
1440 * FUSE_NOWRITE, otherwise fuse_launder_page() would deadlock.
1441 */
1442 if (S_ISREG(inode->i_mode) && oldsize != outarg.attr.size) {
1443 truncate_pagecache(inode, oldsize, outarg.attr.size);
1444 invalidate_inode_pages2(inode->i_mapping);
1445 }
1446
1447 clear_bit(FUSE_I_SIZE_UNSTABLE, &fi->state);
1448 return 0;
1449
1450 error:
1451 if (is_truncate)
1452 fuse_release_nowrite(inode);
1453
1454 clear_bit(FUSE_I_SIZE_UNSTABLE, &fi->state);
1455 return err;
1456 }
1457
fuse_setattr(struct dentry * entry,struct iattr * attr)1458 static int fuse_setattr(struct dentry *entry, struct iattr *attr)
1459 {
1460 if (attr->ia_valid & ATTR_FILE)
1461 return fuse_do_setattr(entry, attr, attr->ia_file);
1462 else
1463 return fuse_do_setattr(entry, attr, NULL);
1464 }
1465
fuse_getattr(struct vfsmount * mnt,struct dentry * entry,struct kstat * stat)1466 static int fuse_getattr(struct vfsmount *mnt, struct dentry *entry,
1467 struct kstat *stat)
1468 {
1469 struct inode *inode = entry->d_inode;
1470 struct fuse_conn *fc = get_fuse_conn(inode);
1471
1472 if (!fuse_allow_task(fc, current))
1473 return -EACCES;
1474
1475 return fuse_update_attributes(inode, stat, NULL, NULL);
1476 }
1477
fuse_setxattr(struct dentry * entry,const char * name,const void * value,size_t size,int flags)1478 static int fuse_setxattr(struct dentry *entry, const char *name,
1479 const void *value, size_t size, int flags)
1480 {
1481 struct inode *inode = entry->d_inode;
1482 struct fuse_conn *fc = get_fuse_conn(inode);
1483 struct fuse_req *req;
1484 struct fuse_setxattr_in inarg;
1485 int err;
1486
1487 if (fc->no_setxattr)
1488 return -EOPNOTSUPP;
1489
1490 req = fuse_get_req(fc);
1491 if (IS_ERR(req))
1492 return PTR_ERR(req);
1493
1494 memset(&inarg, 0, sizeof(inarg));
1495 inarg.size = size;
1496 inarg.flags = flags;
1497 req->in.h.opcode = FUSE_SETXATTR;
1498 req->in.h.nodeid = get_node_id(inode);
1499 req->in.numargs = 3;
1500 req->in.args[0].size = sizeof(inarg);
1501 req->in.args[0].value = &inarg;
1502 req->in.args[1].size = strlen(name) + 1;
1503 req->in.args[1].value = name;
1504 req->in.args[2].size = size;
1505 req->in.args[2].value = value;
1506 fuse_request_send(fc, req);
1507 err = req->out.h.error;
1508 fuse_put_request(fc, req);
1509 if (err == -ENOSYS) {
1510 fc->no_setxattr = 1;
1511 err = -EOPNOTSUPP;
1512 }
1513 if (!err)
1514 fuse_invalidate_attr(inode);
1515 return err;
1516 }
1517
fuse_getxattr(struct dentry * entry,const char * name,void * value,size_t size)1518 static ssize_t fuse_getxattr(struct dentry *entry, const char *name,
1519 void *value, size_t size)
1520 {
1521 struct inode *inode = entry->d_inode;
1522 struct fuse_conn *fc = get_fuse_conn(inode);
1523 struct fuse_req *req;
1524 struct fuse_getxattr_in inarg;
1525 struct fuse_getxattr_out outarg;
1526 ssize_t ret;
1527
1528 if (fc->no_getxattr)
1529 return -EOPNOTSUPP;
1530
1531 req = fuse_get_req(fc);
1532 if (IS_ERR(req))
1533 return PTR_ERR(req);
1534
1535 memset(&inarg, 0, sizeof(inarg));
1536 inarg.size = size;
1537 req->in.h.opcode = FUSE_GETXATTR;
1538 req->in.h.nodeid = get_node_id(inode);
1539 req->in.numargs = 2;
1540 req->in.args[0].size = sizeof(inarg);
1541 req->in.args[0].value = &inarg;
1542 req->in.args[1].size = strlen(name) + 1;
1543 req->in.args[1].value = name;
1544 /* This is really two different operations rolled into one */
1545 req->out.numargs = 1;
1546 if (size) {
1547 req->out.argvar = 1;
1548 req->out.args[0].size = size;
1549 req->out.args[0].value = value;
1550 } else {
1551 req->out.args[0].size = sizeof(outarg);
1552 req->out.args[0].value = &outarg;
1553 }
1554 fuse_request_send(fc, req);
1555 ret = req->out.h.error;
1556 if (!ret)
1557 ret = size ? req->out.args[0].size : outarg.size;
1558 else {
1559 if (ret == -ENOSYS) {
1560 fc->no_getxattr = 1;
1561 ret = -EOPNOTSUPP;
1562 }
1563 }
1564 fuse_put_request(fc, req);
1565 return ret;
1566 }
1567
fuse_listxattr(struct dentry * entry,char * list,size_t size)1568 static ssize_t fuse_listxattr(struct dentry *entry, char *list, size_t size)
1569 {
1570 struct inode *inode = entry->d_inode;
1571 struct fuse_conn *fc = get_fuse_conn(inode);
1572 struct fuse_req *req;
1573 struct fuse_getxattr_in inarg;
1574 struct fuse_getxattr_out outarg;
1575 ssize_t ret;
1576
1577 if (!fuse_allow_task(fc, current))
1578 return -EACCES;
1579
1580 if (fc->no_listxattr)
1581 return -EOPNOTSUPP;
1582
1583 req = fuse_get_req(fc);
1584 if (IS_ERR(req))
1585 return PTR_ERR(req);
1586
1587 memset(&inarg, 0, sizeof(inarg));
1588 inarg.size = size;
1589 req->in.h.opcode = FUSE_LISTXATTR;
1590 req->in.h.nodeid = get_node_id(inode);
1591 req->in.numargs = 1;
1592 req->in.args[0].size = sizeof(inarg);
1593 req->in.args[0].value = &inarg;
1594 /* This is really two different operations rolled into one */
1595 req->out.numargs = 1;
1596 if (size) {
1597 req->out.argvar = 1;
1598 req->out.args[0].size = size;
1599 req->out.args[0].value = list;
1600 } else {
1601 req->out.args[0].size = sizeof(outarg);
1602 req->out.args[0].value = &outarg;
1603 }
1604 fuse_request_send(fc, req);
1605 ret = req->out.h.error;
1606 if (!ret)
1607 ret = size ? req->out.args[0].size : outarg.size;
1608 else {
1609 if (ret == -ENOSYS) {
1610 fc->no_listxattr = 1;
1611 ret = -EOPNOTSUPP;
1612 }
1613 }
1614 fuse_put_request(fc, req);
1615 return ret;
1616 }
1617
fuse_removexattr(struct dentry * entry,const char * name)1618 static int fuse_removexattr(struct dentry *entry, const char *name)
1619 {
1620 struct inode *inode = entry->d_inode;
1621 struct fuse_conn *fc = get_fuse_conn(inode);
1622 struct fuse_req *req;
1623 int err;
1624
1625 if (fc->no_removexattr)
1626 return -EOPNOTSUPP;
1627
1628 req = fuse_get_req(fc);
1629 if (IS_ERR(req))
1630 return PTR_ERR(req);
1631
1632 req->in.h.opcode = FUSE_REMOVEXATTR;
1633 req->in.h.nodeid = get_node_id(inode);
1634 req->in.numargs = 1;
1635 req->in.args[0].size = strlen(name) + 1;
1636 req->in.args[0].value = name;
1637 fuse_request_send(fc, req);
1638 err = req->out.h.error;
1639 fuse_put_request(fc, req);
1640 if (err == -ENOSYS) {
1641 fc->no_removexattr = 1;
1642 err = -EOPNOTSUPP;
1643 }
1644 if (!err)
1645 fuse_invalidate_attr(inode);
1646 return err;
1647 }
1648
1649 static const struct inode_operations fuse_dir_inode_operations = {
1650 .lookup = fuse_lookup,
1651 .mkdir = fuse_mkdir,
1652 .symlink = fuse_symlink,
1653 .unlink = fuse_unlink,
1654 .rmdir = fuse_rmdir,
1655 .rename = fuse_rename,
1656 .link = fuse_link,
1657 .setattr = fuse_setattr,
1658 .create = fuse_create,
1659 .mknod = fuse_mknod,
1660 .permission = fuse_permission,
1661 .getattr = fuse_getattr,
1662 .setxattr = fuse_setxattr,
1663 .getxattr = fuse_getxattr,
1664 .listxattr = fuse_listxattr,
1665 .removexattr = fuse_removexattr,
1666 };
1667
1668 static const struct file_operations fuse_dir_operations = {
1669 .llseek = generic_file_llseek,
1670 .read = generic_read_dir,
1671 .readdir = fuse_readdir,
1672 .open = fuse_dir_open,
1673 .release = fuse_dir_release,
1674 .fsync = fuse_dir_fsync,
1675 .unlocked_ioctl = fuse_dir_ioctl,
1676 .compat_ioctl = fuse_dir_compat_ioctl,
1677 };
1678
1679 static const struct inode_operations fuse_common_inode_operations = {
1680 .setattr = fuse_setattr,
1681 .permission = fuse_permission,
1682 .getattr = fuse_getattr,
1683 .setxattr = fuse_setxattr,
1684 .getxattr = fuse_getxattr,
1685 .listxattr = fuse_listxattr,
1686 .removexattr = fuse_removexattr,
1687 };
1688
1689 static const struct inode_operations fuse_symlink_inode_operations = {
1690 .setattr = fuse_setattr,
1691 .follow_link = fuse_follow_link,
1692 .put_link = fuse_put_link,
1693 .readlink = generic_readlink,
1694 .getattr = fuse_getattr,
1695 .setxattr = fuse_setxattr,
1696 .getxattr = fuse_getxattr,
1697 .listxattr = fuse_listxattr,
1698 .removexattr = fuse_removexattr,
1699 };
1700
fuse_init_common(struct inode * inode)1701 void fuse_init_common(struct inode *inode)
1702 {
1703 inode->i_op = &fuse_common_inode_operations;
1704 }
1705
fuse_init_dir(struct inode * inode)1706 void fuse_init_dir(struct inode *inode)
1707 {
1708 inode->i_op = &fuse_dir_inode_operations;
1709 inode->i_fop = &fuse_dir_operations;
1710 }
1711
fuse_init_symlink(struct inode * inode)1712 void fuse_init_symlink(struct inode *inode)
1713 {
1714 inode->i_op = &fuse_symlink_inode_operations;
1715 }
1716