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TOMOYO Linux Cross Reference
Linux/fs/fuse/dir.c

Version: ~ [ linux-5.1-rc1 ] ~ [ linux-5.0.3 ] ~ [ linux-4.20.17 ] ~ [ linux-4.19.30 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.107 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.164 ] ~ [ linux-4.8.17 ] ~ [ linux-4.7.10 ] ~ [ linux-4.6.7 ] ~ [ linux-4.5.7 ] ~ [ linux-4.4.176 ] ~ [ linux-4.3.6 ] ~ [ linux-4.2.8 ] ~ [ linux-4.1.52 ] ~ [ linux-4.0.9 ] ~ [ linux-3.19.8 ] ~ [ linux-3.18.136 ] ~ [ linux-3.17.8 ] ~ [ linux-3.16.63 ] ~ [ linux-3.15.10 ] ~ [ linux-3.14.79 ] ~ [ linux-3.13.11 ] ~ [ linux-3.12.74 ] ~ [ linux-3.11.10 ] ~ [ linux-3.10.108 ] ~ [ linux-3.9.11 ] ~ [ linux-3.8.13 ] ~ [ linux-3.7.10 ] ~ [ linux-3.6.11 ] ~ [ linux-3.5.7 ] ~ [ linux-3.4.113 ] ~ [ linux-3.3.8 ] ~ [ linux-3.2.102 ] ~ [ linux-3.1.10 ] ~ [ linux-3.0.101 ] ~ [ linux-2.6.39.4 ] ~ [ linux-2.6.38.8 ] ~ [ linux-2.6.37.6 ] ~ [ linux-2.6.36.4 ] ~ [ linux-2.6.35.14 ] ~ [ linux-2.6.34.15 ] ~ [ linux-2.6.33.20 ] ~ [ linux-2.6.32.71 ] ~ [ linux-2.6.0 ] ~ [ linux-2.4.37.11 ] ~ [ unix-v6-master ] ~ [ ccs-tools-1.8.5 ] ~ [ policy-sample ] ~
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  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 #include <linux/xattr.h>
 17 #include <linux/posix_acl.h>
 18 
 19 static bool fuse_use_readdirplus(struct inode *dir, struct dir_context *ctx)
 20 {
 21         struct fuse_conn *fc = get_fuse_conn(dir);
 22         struct fuse_inode *fi = get_fuse_inode(dir);
 23 
 24         if (!fc->do_readdirplus)
 25                 return false;
 26         if (!fc->readdirplus_auto)
 27                 return true;
 28         if (test_and_clear_bit(FUSE_I_ADVISE_RDPLUS, &fi->state))
 29                 return true;
 30         if (ctx->pos == 0)
 31                 return true;
 32         return false;
 33 }
 34 
 35 static void fuse_advise_use_readdirplus(struct inode *dir)
 36 {
 37         struct fuse_inode *fi = get_fuse_inode(dir);
 38 
 39         set_bit(FUSE_I_ADVISE_RDPLUS, &fi->state);
 40 }
 41 
 42 union fuse_dentry {
 43         u64 time;
 44         struct rcu_head rcu;
 45 };
 46 
 47 static inline void fuse_dentry_settime(struct dentry *entry, u64 time)
 48 {
 49         ((union fuse_dentry *) entry->d_fsdata)->time = time;
 50 }
 51 
 52 static inline u64 fuse_dentry_time(struct dentry *entry)
 53 {
 54         return ((union fuse_dentry *) entry->d_fsdata)->time;
 55 }
 56 
 57 /*
 58  * FUSE caches dentries and attributes with separate timeout.  The
 59  * time in jiffies until the dentry/attributes are valid is stored in
 60  * dentry->d_fsdata and fuse_inode->i_time respectively.
 61  */
 62 
 63 /*
 64  * Calculate the time in jiffies until a dentry/attributes are valid
 65  */
 66 static u64 time_to_jiffies(u64 sec, u32 nsec)
 67 {
 68         if (sec || nsec) {
 69                 struct timespec64 ts = {
 70                         sec,
 71                         min_t(u32, nsec, NSEC_PER_SEC - 1)
 72                 };
 73 
 74                 return get_jiffies_64() + timespec64_to_jiffies(&ts);
 75         } else
 76                 return 0;
 77 }
 78 
 79 /*
 80  * Set dentry and possibly attribute timeouts from the lookup/mk*
 81  * replies
 82  */
 83 static void fuse_change_entry_timeout(struct dentry *entry,
 84                                       struct fuse_entry_out *o)
 85 {
 86         fuse_dentry_settime(entry,
 87                 time_to_jiffies(o->entry_valid, o->entry_valid_nsec));
 88 }
 89 
 90 static u64 attr_timeout(struct fuse_attr_out *o)
 91 {
 92         return time_to_jiffies(o->attr_valid, o->attr_valid_nsec);
 93 }
 94 
 95 static u64 entry_attr_timeout(struct fuse_entry_out *o)
 96 {
 97         return time_to_jiffies(o->attr_valid, o->attr_valid_nsec);
 98 }
 99 
100 /*
101  * Mark the attributes as stale, so that at the next call to
102  * ->getattr() they will be fetched from userspace
103  */
104 void fuse_invalidate_attr(struct inode *inode)
105 {
106         get_fuse_inode(inode)->i_time = 0;
107 }
108 
109 /**
110  * Mark the attributes as stale due to an atime change.  Avoid the invalidate if
111  * atime is not used.
112  */
113 void fuse_invalidate_atime(struct inode *inode)
114 {
115         if (!IS_RDONLY(inode))
116                 fuse_invalidate_attr(inode);
117 }
118 
119 /*
120  * Just mark the entry as stale, so that a next attempt to look it up
121  * will result in a new lookup call to userspace
122  *
123  * This is called when a dentry is about to become negative and the
124  * timeout is unknown (unlink, rmdir, rename and in some cases
125  * lookup)
126  */
127 void fuse_invalidate_entry_cache(struct dentry *entry)
128 {
129         fuse_dentry_settime(entry, 0);
130 }
131 
132 /*
133  * Same as fuse_invalidate_entry_cache(), but also try to remove the
134  * dentry from the hash
135  */
136 static void fuse_invalidate_entry(struct dentry *entry)
137 {
138         d_invalidate(entry);
139         fuse_invalidate_entry_cache(entry);
140 }
141 
142 static void fuse_lookup_init(struct fuse_conn *fc, struct fuse_args *args,
143                              u64 nodeid, const struct qstr *name,
144                              struct fuse_entry_out *outarg)
145 {
146         memset(outarg, 0, sizeof(struct fuse_entry_out));
147         args->in.h.opcode = FUSE_LOOKUP;
148         args->in.h.nodeid = nodeid;
149         args->in.numargs = 1;
150         args->in.args[0].size = name->len + 1;
151         args->in.args[0].value = name->name;
152         args->out.numargs = 1;
153         args->out.args[0].size = sizeof(struct fuse_entry_out);
154         args->out.args[0].value = outarg;
155 }
156 
157 u64 fuse_get_attr_version(struct fuse_conn *fc)
158 {
159         u64 curr_version;
160 
161         /*
162          * The spin lock isn't actually needed on 64bit archs, but we
163          * don't yet care too much about such optimizations.
164          */
165         spin_lock(&fc->lock);
166         curr_version = fc->attr_version;
167         spin_unlock(&fc->lock);
168 
169         return curr_version;
170 }
171 
172 /*
173  * Check whether the dentry is still valid
174  *
175  * If the entry validity timeout has expired and the dentry is
176  * positive, try to redo the lookup.  If the lookup results in a
177  * different inode, then let the VFS invalidate the dentry and redo
178  * the lookup once more.  If the lookup results in the same inode,
179  * then refresh the attributes, timeouts and mark the dentry valid.
180  */
181 static int fuse_dentry_revalidate(struct dentry *entry, unsigned int flags)
182 {
183         struct inode *inode;
184         struct dentry *parent;
185         struct fuse_conn *fc;
186         struct fuse_inode *fi;
187         int ret;
188 
189         inode = d_inode_rcu(entry);
190         if (inode && is_bad_inode(inode))
191                 goto invalid;
192         else if (time_before64(fuse_dentry_time(entry), get_jiffies_64()) ||
193                  (flags & LOOKUP_REVAL)) {
194                 struct fuse_entry_out outarg;
195                 FUSE_ARGS(args);
196                 struct fuse_forget_link *forget;
197                 u64 attr_version;
198 
199                 /* For negative dentries, always do a fresh lookup */
200                 if (!inode)
201                         goto invalid;
202 
203                 ret = -ECHILD;
204                 if (flags & LOOKUP_RCU)
205                         goto out;
206 
207                 fc = get_fuse_conn(inode);
208 
209                 forget = fuse_alloc_forget();
210                 ret = -ENOMEM;
211                 if (!forget)
212                         goto out;
213 
214                 attr_version = fuse_get_attr_version(fc);
215 
216                 parent = dget_parent(entry);
217                 fuse_lookup_init(fc, &args, get_node_id(d_inode(parent)),
218                                  &entry->d_name, &outarg);
219                 ret = fuse_simple_request(fc, &args);
220                 dput(parent);
221                 /* Zero nodeid is same as -ENOENT */
222                 if (!ret && !outarg.nodeid)
223                         ret = -ENOENT;
224                 if (!ret) {
225                         fi = get_fuse_inode(inode);
226                         if (outarg.nodeid != get_node_id(inode)) {
227                                 fuse_queue_forget(fc, forget, outarg.nodeid, 1);
228                                 goto invalid;
229                         }
230                         spin_lock(&fc->lock);
231                         fi->nlookup++;
232                         spin_unlock(&fc->lock);
233                 }
234                 kfree(forget);
235                 if (ret == -ENOMEM)
236                         goto out;
237                 if (ret || (outarg.attr.mode ^ inode->i_mode) & S_IFMT)
238                         goto invalid;
239 
240                 forget_all_cached_acls(inode);
241                 fuse_change_attributes(inode, &outarg.attr,
242                                        entry_attr_timeout(&outarg),
243                                        attr_version);
244                 fuse_change_entry_timeout(entry, &outarg);
245         } else if (inode) {
246                 fi = get_fuse_inode(inode);
247                 if (flags & LOOKUP_RCU) {
248                         if (test_bit(FUSE_I_INIT_RDPLUS, &fi->state))
249                                 return -ECHILD;
250                 } else if (test_and_clear_bit(FUSE_I_INIT_RDPLUS, &fi->state)) {
251                         parent = dget_parent(entry);
252                         fuse_advise_use_readdirplus(d_inode(parent));
253                         dput(parent);
254                 }
255         }
256         ret = 1;
257 out:
258         return ret;
259 
260 invalid:
261         ret = 0;
262         goto out;
263 }
264 
265 static int invalid_nodeid(u64 nodeid)
266 {
267         return !nodeid || nodeid == FUSE_ROOT_ID;
268 }
269 
270 static int fuse_dentry_init(struct dentry *dentry)
271 {
272         dentry->d_fsdata = kzalloc(sizeof(union fuse_dentry), GFP_KERNEL);
273 
274         return dentry->d_fsdata ? 0 : -ENOMEM;
275 }
276 static void fuse_dentry_release(struct dentry *dentry)
277 {
278         union fuse_dentry *fd = dentry->d_fsdata;
279 
280         kfree_rcu(fd, rcu);
281 }
282 
283 const struct dentry_operations fuse_dentry_operations = {
284         .d_revalidate   = fuse_dentry_revalidate,
285         .d_init         = fuse_dentry_init,
286         .d_release      = fuse_dentry_release,
287 };
288 
289 const struct dentry_operations fuse_root_dentry_operations = {
290         .d_init         = fuse_dentry_init,
291         .d_release      = fuse_dentry_release,
292 };
293 
294 int fuse_valid_type(int m)
295 {
296         return S_ISREG(m) || S_ISDIR(m) || S_ISLNK(m) || S_ISCHR(m) ||
297                 S_ISBLK(m) || S_ISFIFO(m) || S_ISSOCK(m);
298 }
299 
300 int fuse_lookup_name(struct super_block *sb, u64 nodeid, const struct qstr *name,
301                      struct fuse_entry_out *outarg, struct inode **inode)
302 {
303         struct fuse_conn *fc = get_fuse_conn_super(sb);
304         FUSE_ARGS(args);
305         struct fuse_forget_link *forget;
306         u64 attr_version;
307         int err;
308 
309         *inode = NULL;
310         err = -ENAMETOOLONG;
311         if (name->len > FUSE_NAME_MAX)
312                 goto out;
313 
314 
315         forget = fuse_alloc_forget();
316         err = -ENOMEM;
317         if (!forget)
318                 goto out;
319 
320         attr_version = fuse_get_attr_version(fc);
321 
322         fuse_lookup_init(fc, &args, nodeid, name, outarg);
323         err = fuse_simple_request(fc, &args);
324         /* Zero nodeid is same as -ENOENT, but with valid timeout */
325         if (err || !outarg->nodeid)
326                 goto out_put_forget;
327 
328         err = -EIO;
329         if (!outarg->nodeid)
330                 goto out_put_forget;
331         if (!fuse_valid_type(outarg->attr.mode))
332                 goto out_put_forget;
333 
334         *inode = fuse_iget(sb, outarg->nodeid, outarg->generation,
335                            &outarg->attr, entry_attr_timeout(outarg),
336                            attr_version);
337         err = -ENOMEM;
338         if (!*inode) {
339                 fuse_queue_forget(fc, forget, outarg->nodeid, 1);
340                 goto out;
341         }
342         err = 0;
343 
344  out_put_forget:
345         kfree(forget);
346  out:
347         return err;
348 }
349 
350 static struct dentry *fuse_lookup(struct inode *dir, struct dentry *entry,
351                                   unsigned int flags)
352 {
353         int err;
354         struct fuse_entry_out outarg;
355         struct inode *inode;
356         struct dentry *newent;
357         bool outarg_valid = true;
358 
359         fuse_lock_inode(dir);
360         err = fuse_lookup_name(dir->i_sb, get_node_id(dir), &entry->d_name,
361                                &outarg, &inode);
362         fuse_unlock_inode(dir);
363         if (err == -ENOENT) {
364                 outarg_valid = false;
365                 err = 0;
366         }
367         if (err)
368                 goto out_err;
369 
370         err = -EIO;
371         if (inode && get_node_id(inode) == FUSE_ROOT_ID)
372                 goto out_iput;
373 
374         newent = d_splice_alias(inode, entry);
375         err = PTR_ERR(newent);
376         if (IS_ERR(newent))
377                 goto out_err;
378 
379         entry = newent ? newent : entry;
380         if (outarg_valid)
381                 fuse_change_entry_timeout(entry, &outarg);
382         else
383                 fuse_invalidate_entry_cache(entry);
384 
385         fuse_advise_use_readdirplus(dir);
386         return newent;
387 
388  out_iput:
389         iput(inode);
390  out_err:
391         return ERR_PTR(err);
392 }
393 
394 /*
395  * Atomic create+open operation
396  *
397  * If the filesystem doesn't support this, then fall back to separate
398  * 'mknod' + 'open' requests.
399  */
400 static int fuse_create_open(struct inode *dir, struct dentry *entry,
401                             struct file *file, unsigned flags,
402                             umode_t mode, int *opened)
403 {
404         int err;
405         struct inode *inode;
406         struct fuse_conn *fc = get_fuse_conn(dir);
407         FUSE_ARGS(args);
408         struct fuse_forget_link *forget;
409         struct fuse_create_in inarg;
410         struct fuse_open_out outopen;
411         struct fuse_entry_out outentry;
412         struct fuse_file *ff;
413 
414         /* Userspace expects S_IFREG in create mode */
415         BUG_ON((mode & S_IFMT) != S_IFREG);
416 
417         forget = fuse_alloc_forget();
418         err = -ENOMEM;
419         if (!forget)
420                 goto out_err;
421 
422         err = -ENOMEM;
423         ff = fuse_file_alloc(fc);
424         if (!ff)
425                 goto out_put_forget_req;
426 
427         if (!fc->dont_mask)
428                 mode &= ~current_umask();
429 
430         flags &= ~O_NOCTTY;
431         memset(&inarg, 0, sizeof(inarg));
432         memset(&outentry, 0, sizeof(outentry));
433         inarg.flags = flags;
434         inarg.mode = mode;
435         inarg.umask = current_umask();
436         args.in.h.opcode = FUSE_CREATE;
437         args.in.h.nodeid = get_node_id(dir);
438         args.in.numargs = 2;
439         args.in.args[0].size = sizeof(inarg);
440         args.in.args[0].value = &inarg;
441         args.in.args[1].size = entry->d_name.len + 1;
442         args.in.args[1].value = entry->d_name.name;
443         args.out.numargs = 2;
444         args.out.args[0].size = sizeof(outentry);
445         args.out.args[0].value = &outentry;
446         args.out.args[1].size = sizeof(outopen);
447         args.out.args[1].value = &outopen;
448         err = fuse_simple_request(fc, &args);
449         if (err)
450                 goto out_free_ff;
451 
452         err = -EIO;
453         if (!S_ISREG(outentry.attr.mode) || invalid_nodeid(outentry.nodeid))
454                 goto out_free_ff;
455 
456         ff->fh = outopen.fh;
457         ff->nodeid = outentry.nodeid;
458         ff->open_flags = outopen.open_flags;
459         inode = fuse_iget(dir->i_sb, outentry.nodeid, outentry.generation,
460                           &outentry.attr, entry_attr_timeout(&outentry), 0);
461         if (!inode) {
462                 flags &= ~(O_CREAT | O_EXCL | O_TRUNC);
463                 fuse_sync_release(ff, flags);
464                 fuse_queue_forget(fc, forget, outentry.nodeid, 1);
465                 err = -ENOMEM;
466                 goto out_err;
467         }
468         kfree(forget);
469         d_instantiate(entry, inode);
470         fuse_change_entry_timeout(entry, &outentry);
471         fuse_invalidate_attr(dir);
472         err = finish_open(file, entry, generic_file_open, opened);
473         if (err) {
474                 fuse_sync_release(ff, flags);
475         } else {
476                 file->private_data = ff;
477                 fuse_finish_open(inode, file);
478         }
479         return err;
480 
481 out_free_ff:
482         fuse_file_free(ff);
483 out_put_forget_req:
484         kfree(forget);
485 out_err:
486         return err;
487 }
488 
489 static int fuse_mknod(struct inode *, struct dentry *, umode_t, dev_t);
490 static int fuse_atomic_open(struct inode *dir, struct dentry *entry,
491                             struct file *file, unsigned flags,
492                             umode_t mode, int *opened)
493 {
494         int err;
495         struct fuse_conn *fc = get_fuse_conn(dir);
496         struct dentry *res = NULL;
497 
498         if (d_in_lookup(entry)) {
499                 res = fuse_lookup(dir, entry, 0);
500                 if (IS_ERR(res))
501                         return PTR_ERR(res);
502 
503                 if (res)
504                         entry = res;
505         }
506 
507         if (!(flags & O_CREAT) || d_really_is_positive(entry))
508                 goto no_open;
509 
510         /* Only creates */
511         *opened |= FILE_CREATED;
512 
513         if (fc->no_create)
514                 goto mknod;
515 
516         err = fuse_create_open(dir, entry, file, flags, mode, opened);
517         if (err == -ENOSYS) {
518                 fc->no_create = 1;
519                 goto mknod;
520         }
521 out_dput:
522         dput(res);
523         return err;
524 
525 mknod:
526         err = fuse_mknod(dir, entry, mode, 0);
527         if (err)
528                 goto out_dput;
529 no_open:
530         return finish_no_open(file, res);
531 }
532 
533 /*
534  * Code shared between mknod, mkdir, symlink and link
535  */
536 static int create_new_entry(struct fuse_conn *fc, struct fuse_args *args,
537                             struct inode *dir, struct dentry *entry,
538                             umode_t mode)
539 {
540         struct fuse_entry_out outarg;
541         struct inode *inode;
542         int err;
543         struct fuse_forget_link *forget;
544 
545         forget = fuse_alloc_forget();
546         if (!forget)
547                 return -ENOMEM;
548 
549         memset(&outarg, 0, sizeof(outarg));
550         args->in.h.nodeid = get_node_id(dir);
551         args->out.numargs = 1;
552         args->out.args[0].size = sizeof(outarg);
553         args->out.args[0].value = &outarg;
554         err = fuse_simple_request(fc, args);
555         if (err)
556                 goto out_put_forget_req;
557 
558         err = -EIO;
559         if (invalid_nodeid(outarg.nodeid))
560                 goto out_put_forget_req;
561 
562         if ((outarg.attr.mode ^ mode) & S_IFMT)
563                 goto out_put_forget_req;
564 
565         inode = fuse_iget(dir->i_sb, outarg.nodeid, outarg.generation,
566                           &outarg.attr, entry_attr_timeout(&outarg), 0);
567         if (!inode) {
568                 fuse_queue_forget(fc, forget, outarg.nodeid, 1);
569                 return -ENOMEM;
570         }
571         kfree(forget);
572 
573         err = d_instantiate_no_diralias(entry, inode);
574         if (err)
575                 return err;
576 
577         fuse_change_entry_timeout(entry, &outarg);
578         fuse_invalidate_attr(dir);
579         return 0;
580 
581  out_put_forget_req:
582         kfree(forget);
583         return err;
584 }
585 
586 static int fuse_mknod(struct inode *dir, struct dentry *entry, umode_t mode,
587                       dev_t rdev)
588 {
589         struct fuse_mknod_in inarg;
590         struct fuse_conn *fc = get_fuse_conn(dir);
591         FUSE_ARGS(args);
592 
593         if (!fc->dont_mask)
594                 mode &= ~current_umask();
595 
596         memset(&inarg, 0, sizeof(inarg));
597         inarg.mode = mode;
598         inarg.rdev = new_encode_dev(rdev);
599         inarg.umask = current_umask();
600         args.in.h.opcode = FUSE_MKNOD;
601         args.in.numargs = 2;
602         args.in.args[0].size = sizeof(inarg);
603         args.in.args[0].value = &inarg;
604         args.in.args[1].size = entry->d_name.len + 1;
605         args.in.args[1].value = entry->d_name.name;
606         return create_new_entry(fc, &args, dir, entry, mode);
607 }
608 
609 static int fuse_create(struct inode *dir, struct dentry *entry, umode_t mode,
610                        bool excl)
611 {
612         return fuse_mknod(dir, entry, mode, 0);
613 }
614 
615 static int fuse_mkdir(struct inode *dir, struct dentry *entry, umode_t mode)
616 {
617         struct fuse_mkdir_in inarg;
618         struct fuse_conn *fc = get_fuse_conn(dir);
619         FUSE_ARGS(args);
620 
621         if (!fc->dont_mask)
622                 mode &= ~current_umask();
623 
624         memset(&inarg, 0, sizeof(inarg));
625         inarg.mode = mode;
626         inarg.umask = current_umask();
627         args.in.h.opcode = FUSE_MKDIR;
628         args.in.numargs = 2;
629         args.in.args[0].size = sizeof(inarg);
630         args.in.args[0].value = &inarg;
631         args.in.args[1].size = entry->d_name.len + 1;
632         args.in.args[1].value = entry->d_name.name;
633         return create_new_entry(fc, &args, dir, entry, S_IFDIR);
634 }
635 
636 static int fuse_symlink(struct inode *dir, struct dentry *entry,
637                         const char *link)
638 {
639         struct fuse_conn *fc = get_fuse_conn(dir);
640         unsigned len = strlen(link) + 1;
641         FUSE_ARGS(args);
642 
643         args.in.h.opcode = FUSE_SYMLINK;
644         args.in.numargs = 2;
645         args.in.args[0].size = entry->d_name.len + 1;
646         args.in.args[0].value = entry->d_name.name;
647         args.in.args[1].size = len;
648         args.in.args[1].value = link;
649         return create_new_entry(fc, &args, dir, entry, S_IFLNK);
650 }
651 
652 void fuse_update_ctime(struct inode *inode)
653 {
654         if (!IS_NOCMTIME(inode)) {
655                 inode->i_ctime = current_time(inode);
656                 mark_inode_dirty_sync(inode);
657         }
658 }
659 
660 static int fuse_unlink(struct inode *dir, struct dentry *entry)
661 {
662         int err;
663         struct fuse_conn *fc = get_fuse_conn(dir);
664         FUSE_ARGS(args);
665 
666         args.in.h.opcode = FUSE_UNLINK;
667         args.in.h.nodeid = get_node_id(dir);
668         args.in.numargs = 1;
669         args.in.args[0].size = entry->d_name.len + 1;
670         args.in.args[0].value = entry->d_name.name;
671         err = fuse_simple_request(fc, &args);
672         if (!err) {
673                 struct inode *inode = d_inode(entry);
674                 struct fuse_inode *fi = get_fuse_inode(inode);
675 
676                 spin_lock(&fc->lock);
677                 fi->attr_version = ++fc->attr_version;
678                 /*
679                  * If i_nlink == 0 then unlink doesn't make sense, yet this can
680                  * happen if userspace filesystem is careless.  It would be
681                  * difficult to enforce correct nlink usage so just ignore this
682                  * condition here
683                  */
684                 if (inode->i_nlink > 0)
685                         drop_nlink(inode);
686                 spin_unlock(&fc->lock);
687                 fuse_invalidate_attr(inode);
688                 fuse_invalidate_attr(dir);
689                 fuse_invalidate_entry_cache(entry);
690                 fuse_update_ctime(inode);
691         } else if (err == -EINTR)
692                 fuse_invalidate_entry(entry);
693         return err;
694 }
695 
696 static int fuse_rmdir(struct inode *dir, struct dentry *entry)
697 {
698         int err;
699         struct fuse_conn *fc = get_fuse_conn(dir);
700         FUSE_ARGS(args);
701 
702         args.in.h.opcode = FUSE_RMDIR;
703         args.in.h.nodeid = get_node_id(dir);
704         args.in.numargs = 1;
705         args.in.args[0].size = entry->d_name.len + 1;
706         args.in.args[0].value = entry->d_name.name;
707         err = fuse_simple_request(fc, &args);
708         if (!err) {
709                 clear_nlink(d_inode(entry));
710                 fuse_invalidate_attr(dir);
711                 fuse_invalidate_entry_cache(entry);
712         } else if (err == -EINTR)
713                 fuse_invalidate_entry(entry);
714         return err;
715 }
716 
717 static int fuse_rename_common(struct inode *olddir, struct dentry *oldent,
718                               struct inode *newdir, struct dentry *newent,
719                               unsigned int flags, int opcode, size_t argsize)
720 {
721         int err;
722         struct fuse_rename2_in inarg;
723         struct fuse_conn *fc = get_fuse_conn(olddir);
724         FUSE_ARGS(args);
725 
726         memset(&inarg, 0, argsize);
727         inarg.newdir = get_node_id(newdir);
728         inarg.flags = flags;
729         args.in.h.opcode = opcode;
730         args.in.h.nodeid = get_node_id(olddir);
731         args.in.numargs = 3;
732         args.in.args[0].size = argsize;
733         args.in.args[0].value = &inarg;
734         args.in.args[1].size = oldent->d_name.len + 1;
735         args.in.args[1].value = oldent->d_name.name;
736         args.in.args[2].size = newent->d_name.len + 1;
737         args.in.args[2].value = newent->d_name.name;
738         err = fuse_simple_request(fc, &args);
739         if (!err) {
740                 /* ctime changes */
741                 fuse_invalidate_attr(d_inode(oldent));
742                 fuse_update_ctime(d_inode(oldent));
743 
744                 if (flags & RENAME_EXCHANGE) {
745                         fuse_invalidate_attr(d_inode(newent));
746                         fuse_update_ctime(d_inode(newent));
747                 }
748 
749                 fuse_invalidate_attr(olddir);
750                 if (olddir != newdir)
751                         fuse_invalidate_attr(newdir);
752 
753                 /* newent will end up negative */
754                 if (!(flags & RENAME_EXCHANGE) && d_really_is_positive(newent)) {
755                         fuse_invalidate_attr(d_inode(newent));
756                         fuse_invalidate_entry_cache(newent);
757                         fuse_update_ctime(d_inode(newent));
758                 }
759         } else if (err == -EINTR) {
760                 /* If request was interrupted, DEITY only knows if the
761                    rename actually took place.  If the invalidation
762                    fails (e.g. some process has CWD under the renamed
763                    directory), then there can be inconsistency between
764                    the dcache and the real filesystem.  Tough luck. */
765                 fuse_invalidate_entry(oldent);
766                 if (d_really_is_positive(newent))
767                         fuse_invalidate_entry(newent);
768         }
769 
770         return err;
771 }
772 
773 static int fuse_rename2(struct inode *olddir, struct dentry *oldent,
774                         struct inode *newdir, struct dentry *newent,
775                         unsigned int flags)
776 {
777         struct fuse_conn *fc = get_fuse_conn(olddir);
778         int err;
779 
780         if (flags & ~(RENAME_NOREPLACE | RENAME_EXCHANGE))
781                 return -EINVAL;
782 
783         if (flags) {
784                 if (fc->no_rename2 || fc->minor < 23)
785                         return -EINVAL;
786 
787                 err = fuse_rename_common(olddir, oldent, newdir, newent, flags,
788                                          FUSE_RENAME2,
789                                          sizeof(struct fuse_rename2_in));
790                 if (err == -ENOSYS) {
791                         fc->no_rename2 = 1;
792                         err = -EINVAL;
793                 }
794         } else {
795                 err = fuse_rename_common(olddir, oldent, newdir, newent, 0,
796                                          FUSE_RENAME,
797                                          sizeof(struct fuse_rename_in));
798         }
799 
800         return err;
801 }
802 
803 static int fuse_link(struct dentry *entry, struct inode *newdir,
804                      struct dentry *newent)
805 {
806         int err;
807         struct fuse_link_in inarg;
808         struct inode *inode = d_inode(entry);
809         struct fuse_conn *fc = get_fuse_conn(inode);
810         FUSE_ARGS(args);
811 
812         memset(&inarg, 0, sizeof(inarg));
813         inarg.oldnodeid = get_node_id(inode);
814         args.in.h.opcode = FUSE_LINK;
815         args.in.numargs = 2;
816         args.in.args[0].size = sizeof(inarg);
817         args.in.args[0].value = &inarg;
818         args.in.args[1].size = newent->d_name.len + 1;
819         args.in.args[1].value = newent->d_name.name;
820         err = create_new_entry(fc, &args, newdir, newent, inode->i_mode);
821         /* Contrary to "normal" filesystems it can happen that link
822            makes two "logical" inodes point to the same "physical"
823            inode.  We invalidate the attributes of the old one, so it
824            will reflect changes in the backing inode (link count,
825            etc.)
826         */
827         if (!err) {
828                 struct fuse_inode *fi = get_fuse_inode(inode);
829 
830                 spin_lock(&fc->lock);
831                 fi->attr_version = ++fc->attr_version;
832                 inc_nlink(inode);
833                 spin_unlock(&fc->lock);
834                 fuse_invalidate_attr(inode);
835                 fuse_update_ctime(inode);
836         } else if (err == -EINTR) {
837                 fuse_invalidate_attr(inode);
838         }
839         return err;
840 }
841 
842 static void fuse_fillattr(struct inode *inode, struct fuse_attr *attr,
843                           struct kstat *stat)
844 {
845         unsigned int blkbits;
846         struct fuse_conn *fc = get_fuse_conn(inode);
847 
848         /* see the comment in fuse_change_attributes() */
849         if (fc->writeback_cache && S_ISREG(inode->i_mode)) {
850                 attr->size = i_size_read(inode);
851                 attr->mtime = inode->i_mtime.tv_sec;
852                 attr->mtimensec = inode->i_mtime.tv_nsec;
853                 attr->ctime = inode->i_ctime.tv_sec;
854                 attr->ctimensec = inode->i_ctime.tv_nsec;
855         }
856 
857         stat->dev = inode->i_sb->s_dev;
858         stat->ino = attr->ino;
859         stat->mode = (inode->i_mode & S_IFMT) | (attr->mode & 07777);
860         stat->nlink = attr->nlink;
861         stat->uid = make_kuid(&init_user_ns, attr->uid);
862         stat->gid = make_kgid(&init_user_ns, attr->gid);
863         stat->rdev = inode->i_rdev;
864         stat->atime.tv_sec = attr->atime;
865         stat->atime.tv_nsec = attr->atimensec;
866         stat->mtime.tv_sec = attr->mtime;
867         stat->mtime.tv_nsec = attr->mtimensec;
868         stat->ctime.tv_sec = attr->ctime;
869         stat->ctime.tv_nsec = attr->ctimensec;
870         stat->size = attr->size;
871         stat->blocks = attr->blocks;
872 
873         if (attr->blksize != 0)
874                 blkbits = ilog2(attr->blksize);
875         else
876                 blkbits = inode->i_sb->s_blocksize_bits;
877 
878         stat->blksize = 1 << blkbits;
879 }
880 
881 static int fuse_do_getattr(struct inode *inode, struct kstat *stat,
882                            struct file *file)
883 {
884         int err;
885         struct fuse_getattr_in inarg;
886         struct fuse_attr_out outarg;
887         struct fuse_conn *fc = get_fuse_conn(inode);
888         FUSE_ARGS(args);
889         u64 attr_version;
890 
891         attr_version = fuse_get_attr_version(fc);
892 
893         memset(&inarg, 0, sizeof(inarg));
894         memset(&outarg, 0, sizeof(outarg));
895         /* Directories have separate file-handle space */
896         if (file && S_ISREG(inode->i_mode)) {
897                 struct fuse_file *ff = file->private_data;
898 
899                 inarg.getattr_flags |= FUSE_GETATTR_FH;
900                 inarg.fh = ff->fh;
901         }
902         args.in.h.opcode = FUSE_GETATTR;
903         args.in.h.nodeid = get_node_id(inode);
904         args.in.numargs = 1;
905         args.in.args[0].size = sizeof(inarg);
906         args.in.args[0].value = &inarg;
907         args.out.numargs = 1;
908         args.out.args[0].size = sizeof(outarg);
909         args.out.args[0].value = &outarg;
910         err = fuse_simple_request(fc, &args);
911         if (!err) {
912                 if ((inode->i_mode ^ outarg.attr.mode) & S_IFMT) {
913                         make_bad_inode(inode);
914                         err = -EIO;
915                 } else {
916                         fuse_change_attributes(inode, &outarg.attr,
917                                                attr_timeout(&outarg),
918                                                attr_version);
919                         if (stat)
920                                 fuse_fillattr(inode, &outarg.attr, stat);
921                 }
922         }
923         return err;
924 }
925 
926 static int fuse_update_get_attr(struct inode *inode, struct file *file,
927                                 struct kstat *stat)
928 {
929         struct fuse_inode *fi = get_fuse_inode(inode);
930         int err = 0;
931 
932         if (time_before64(fi->i_time, get_jiffies_64())) {
933                 forget_all_cached_acls(inode);
934                 err = fuse_do_getattr(inode, stat, file);
935         } else if (stat) {
936                 generic_fillattr(inode, stat);
937                 stat->mode = fi->orig_i_mode;
938                 stat->ino = fi->orig_ino;
939         }
940 
941         return err;
942 }
943 
944 int fuse_update_attributes(struct inode *inode, struct file *file)
945 {
946         return fuse_update_get_attr(inode, file, NULL);
947 }
948 
949 int fuse_reverse_inval_entry(struct super_block *sb, u64 parent_nodeid,
950                              u64 child_nodeid, struct qstr *name)
951 {
952         int err = -ENOTDIR;
953         struct inode *parent;
954         struct dentry *dir;
955         struct dentry *entry;
956 
957         parent = ilookup5(sb, parent_nodeid, fuse_inode_eq, &parent_nodeid);
958         if (!parent)
959                 return -ENOENT;
960 
961         inode_lock(parent);
962         if (!S_ISDIR(parent->i_mode))
963                 goto unlock;
964 
965         err = -ENOENT;
966         dir = d_find_alias(parent);
967         if (!dir)
968                 goto unlock;
969 
970         name->hash = full_name_hash(dir, name->name, name->len);
971         entry = d_lookup(dir, name);
972         dput(dir);
973         if (!entry)
974                 goto unlock;
975 
976         fuse_invalidate_attr(parent);
977         fuse_invalidate_entry(entry);
978 
979         if (child_nodeid != 0 && d_really_is_positive(entry)) {
980                 inode_lock(d_inode(entry));
981                 if (get_node_id(d_inode(entry)) != child_nodeid) {
982                         err = -ENOENT;
983                         goto badentry;
984                 }
985                 if (d_mountpoint(entry)) {
986                         err = -EBUSY;
987                         goto badentry;
988                 }
989                 if (d_is_dir(entry)) {
990                         shrink_dcache_parent(entry);
991                         if (!simple_empty(entry)) {
992                                 err = -ENOTEMPTY;
993                                 goto badentry;
994                         }
995                         d_inode(entry)->i_flags |= S_DEAD;
996                 }
997                 dont_mount(entry);
998                 clear_nlink(d_inode(entry));
999                 err = 0;
1000  badentry:
1001                 inode_unlock(d_inode(entry));
1002                 if (!err)
1003                         d_delete(entry);
1004         } else {
1005                 err = 0;
1006         }
1007         dput(entry);
1008 
1009  unlock:
1010         inode_unlock(parent);
1011         iput(parent);
1012         return err;
1013 }
1014 
1015 /*
1016  * Calling into a user-controlled filesystem gives the filesystem
1017  * daemon ptrace-like capabilities over the current process.  This
1018  * means, that the filesystem daemon is able to record the exact
1019  * filesystem operations performed, and can also control the behavior
1020  * of the requester process in otherwise impossible ways.  For example
1021  * it can delay the operation for arbitrary length of time allowing
1022  * DoS against the requester.
1023  *
1024  * For this reason only those processes can call into the filesystem,
1025  * for which the owner of the mount has ptrace privilege.  This
1026  * excludes processes started by other users, suid or sgid processes.
1027  */
1028 int fuse_allow_current_process(struct fuse_conn *fc)
1029 {
1030         const struct cred *cred;
1031 
1032         if (fc->allow_other)
1033                 return 1;
1034 
1035         cred = current_cred();
1036         if (uid_eq(cred->euid, fc->user_id) &&
1037             uid_eq(cred->suid, fc->user_id) &&
1038             uid_eq(cred->uid,  fc->user_id) &&
1039             gid_eq(cred->egid, fc->group_id) &&
1040             gid_eq(cred->sgid, fc->group_id) &&
1041             gid_eq(cred->gid,  fc->group_id))
1042                 return 1;
1043 
1044         return 0;
1045 }
1046 
1047 static int fuse_access(struct inode *inode, int mask)
1048 {
1049         struct fuse_conn *fc = get_fuse_conn(inode);
1050         FUSE_ARGS(args);
1051         struct fuse_access_in inarg;
1052         int err;
1053 
1054         BUG_ON(mask & MAY_NOT_BLOCK);
1055 
1056         if (fc->no_access)
1057                 return 0;
1058 
1059         memset(&inarg, 0, sizeof(inarg));
1060         inarg.mask = mask & (MAY_READ | MAY_WRITE | MAY_EXEC);
1061         args.in.h.opcode = FUSE_ACCESS;
1062         args.in.h.nodeid = get_node_id(inode);
1063         args.in.numargs = 1;
1064         args.in.args[0].size = sizeof(inarg);
1065         args.in.args[0].value = &inarg;
1066         err = fuse_simple_request(fc, &args);
1067         if (err == -ENOSYS) {
1068                 fc->no_access = 1;
1069                 err = 0;
1070         }
1071         return err;
1072 }
1073 
1074 static int fuse_perm_getattr(struct inode *inode, int mask)
1075 {
1076         if (mask & MAY_NOT_BLOCK)
1077                 return -ECHILD;
1078 
1079         forget_all_cached_acls(inode);
1080         return fuse_do_getattr(inode, NULL, NULL);
1081 }
1082 
1083 /*
1084  * Check permission.  The two basic access models of FUSE are:
1085  *
1086  * 1) Local access checking ('default_permissions' mount option) based
1087  * on file mode.  This is the plain old disk filesystem permission
1088  * modell.
1089  *
1090  * 2) "Remote" access checking, where server is responsible for
1091  * checking permission in each inode operation.  An exception to this
1092  * is if ->permission() was invoked from sys_access() in which case an
1093  * access request is sent.  Execute permission is still checked
1094  * locally based on file mode.
1095  */
1096 static int fuse_permission(struct inode *inode, int mask)
1097 {
1098         struct fuse_conn *fc = get_fuse_conn(inode);
1099         bool refreshed = false;
1100         int err = 0;
1101 
1102         if (!fuse_allow_current_process(fc))
1103                 return -EACCES;
1104 
1105         /*
1106          * If attributes are needed, refresh them before proceeding
1107          */
1108         if (fc->default_permissions ||
1109             ((mask & MAY_EXEC) && S_ISREG(inode->i_mode))) {
1110                 struct fuse_inode *fi = get_fuse_inode(inode);
1111 
1112                 if (time_before64(fi->i_time, get_jiffies_64())) {
1113                         refreshed = true;
1114 
1115                         err = fuse_perm_getattr(inode, mask);
1116                         if (err)
1117                                 return err;
1118                 }
1119         }
1120 
1121         if (fc->default_permissions) {
1122                 err = generic_permission(inode, mask);
1123 
1124                 /* If permission is denied, try to refresh file
1125                    attributes.  This is also needed, because the root
1126                    node will at first have no permissions */
1127                 if (err == -EACCES && !refreshed) {
1128                         err = fuse_perm_getattr(inode, mask);
1129                         if (!err)
1130                                 err = generic_permission(inode, mask);
1131                 }
1132 
1133                 /* Note: the opposite of the above test does not
1134                    exist.  So if permissions are revoked this won't be
1135                    noticed immediately, only after the attribute
1136                    timeout has expired */
1137         } else if (mask & (MAY_ACCESS | MAY_CHDIR)) {
1138                 err = fuse_access(inode, mask);
1139         } else if ((mask & MAY_EXEC) && S_ISREG(inode->i_mode)) {
1140                 if (!(inode->i_mode & S_IXUGO)) {
1141                         if (refreshed)
1142                                 return -EACCES;
1143 
1144                         err = fuse_perm_getattr(inode, mask);
1145                         if (!err && !(inode->i_mode & S_IXUGO))
1146                                 return -EACCES;
1147                 }
1148         }
1149         return err;
1150 }
1151 
1152 static int parse_dirfile(char *buf, size_t nbytes, struct file *file,
1153                          struct dir_context *ctx)
1154 {
1155         while (nbytes >= FUSE_NAME_OFFSET) {
1156                 struct fuse_dirent *dirent = (struct fuse_dirent *) buf;
1157                 size_t reclen = FUSE_DIRENT_SIZE(dirent);
1158                 if (!dirent->namelen || dirent->namelen > FUSE_NAME_MAX)
1159                         return -EIO;
1160                 if (reclen > nbytes)
1161                         break;
1162                 if (memchr(dirent->name, '/', dirent->namelen) != NULL)
1163                         return -EIO;
1164 
1165                 if (!dir_emit(ctx, dirent->name, dirent->namelen,
1166                                dirent->ino, dirent->type))
1167                         break;
1168 
1169                 buf += reclen;
1170                 nbytes -= reclen;
1171                 ctx->pos = dirent->off;
1172         }
1173 
1174         return 0;
1175 }
1176 
1177 static int fuse_direntplus_link(struct file *file,
1178                                 struct fuse_direntplus *direntplus,
1179                                 u64 attr_version)
1180 {
1181         struct fuse_entry_out *o = &direntplus->entry_out;
1182         struct fuse_dirent *dirent = &direntplus->dirent;
1183         struct dentry *parent = file->f_path.dentry;
1184         struct qstr name = QSTR_INIT(dirent->name, dirent->namelen);
1185         struct dentry *dentry;
1186         struct dentry *alias;
1187         struct inode *dir = d_inode(parent);
1188         struct fuse_conn *fc;
1189         struct inode *inode;
1190         DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq);
1191 
1192         if (!o->nodeid) {
1193                 /*
1194                  * Unlike in the case of fuse_lookup, zero nodeid does not mean
1195                  * ENOENT. Instead, it only means the userspace filesystem did
1196                  * not want to return attributes/handle for this entry.
1197                  *
1198                  * So do nothing.
1199                  */
1200                 return 0;
1201         }
1202 
1203         if (name.name[0] == '.') {
1204                 /*
1205                  * We could potentially refresh the attributes of the directory
1206                  * and its parent?
1207                  */
1208                 if (name.len == 1)
1209                         return 0;
1210                 if (name.name[1] == '.' && name.len == 2)
1211                         return 0;
1212         }
1213 
1214         if (invalid_nodeid(o->nodeid))
1215                 return -EIO;
1216         if (!fuse_valid_type(o->attr.mode))
1217                 return -EIO;
1218 
1219         fc = get_fuse_conn(dir);
1220 
1221         name.hash = full_name_hash(parent, name.name, name.len);
1222         dentry = d_lookup(parent, &name);
1223         if (!dentry) {
1224 retry:
1225                 dentry = d_alloc_parallel(parent, &name, &wq);
1226                 if (IS_ERR(dentry))
1227                         return PTR_ERR(dentry);
1228         }
1229         if (!d_in_lookup(dentry)) {
1230                 struct fuse_inode *fi;
1231                 inode = d_inode(dentry);
1232                 if (!inode ||
1233                     get_node_id(inode) != o->nodeid ||
1234                     ((o->attr.mode ^ inode->i_mode) & S_IFMT)) {
1235                         d_invalidate(dentry);
1236                         dput(dentry);
1237                         goto retry;
1238                 }
1239                 if (is_bad_inode(inode)) {
1240                         dput(dentry);
1241                         return -EIO;
1242                 }
1243 
1244                 fi = get_fuse_inode(inode);
1245                 spin_lock(&fc->lock);
1246                 fi->nlookup++;
1247                 spin_unlock(&fc->lock);
1248 
1249                 forget_all_cached_acls(inode);
1250                 fuse_change_attributes(inode, &o->attr,
1251                                        entry_attr_timeout(o),
1252                                        attr_version);
1253                 /*
1254                  * The other branch comes via fuse_iget()
1255                  * which bumps nlookup inside
1256                  */
1257         } else {
1258                 inode = fuse_iget(dir->i_sb, o->nodeid, o->generation,
1259                                   &o->attr, entry_attr_timeout(o),
1260                                   attr_version);
1261                 if (!inode)
1262                         inode = ERR_PTR(-ENOMEM);
1263 
1264                 alias = d_splice_alias(inode, dentry);
1265                 d_lookup_done(dentry);
1266                 if (alias) {
1267                         dput(dentry);
1268                         dentry = alias;
1269                 }
1270                 if (IS_ERR(dentry))
1271                         return PTR_ERR(dentry);
1272         }
1273         if (fc->readdirplus_auto)
1274                 set_bit(FUSE_I_INIT_RDPLUS, &get_fuse_inode(inode)->state);
1275         fuse_change_entry_timeout(dentry, o);
1276 
1277         dput(dentry);
1278         return 0;
1279 }
1280 
1281 static int parse_dirplusfile(char *buf, size_t nbytes, struct file *file,
1282                              struct dir_context *ctx, u64 attr_version)
1283 {
1284         struct fuse_direntplus *direntplus;
1285         struct fuse_dirent *dirent;
1286         size_t reclen;
1287         int over = 0;
1288         int ret;
1289 
1290         while (nbytes >= FUSE_NAME_OFFSET_DIRENTPLUS) {
1291                 direntplus = (struct fuse_direntplus *) buf;
1292                 dirent = &direntplus->dirent;
1293                 reclen = FUSE_DIRENTPLUS_SIZE(direntplus);
1294 
1295                 if (!dirent->namelen || dirent->namelen > FUSE_NAME_MAX)
1296                         return -EIO;
1297                 if (reclen > nbytes)
1298                         break;
1299                 if (memchr(dirent->name, '/', dirent->namelen) != NULL)
1300                         return -EIO;
1301 
1302                 if (!over) {
1303                         /* We fill entries into dstbuf only as much as
1304                            it can hold. But we still continue iterating
1305                            over remaining entries to link them. If not,
1306                            we need to send a FORGET for each of those
1307                            which we did not link.
1308                         */
1309                         over = !dir_emit(ctx, dirent->name, dirent->namelen,
1310                                        dirent->ino, dirent->type);
1311                         if (!over)
1312                                 ctx->pos = dirent->off;
1313                 }
1314 
1315                 buf += reclen;
1316                 nbytes -= reclen;
1317 
1318                 ret = fuse_direntplus_link(file, direntplus, attr_version);
1319                 if (ret)
1320                         fuse_force_forget(file, direntplus->entry_out.nodeid);
1321         }
1322 
1323         return 0;
1324 }
1325 
1326 static int fuse_readdir(struct file *file, struct dir_context *ctx)
1327 {
1328         int plus, err;
1329         size_t nbytes;
1330         struct page *page;
1331         struct inode *inode = file_inode(file);
1332         struct fuse_conn *fc = get_fuse_conn(inode);
1333         struct fuse_req *req;
1334         u64 attr_version = 0;
1335 
1336         if (is_bad_inode(inode))
1337                 return -EIO;
1338 
1339         req = fuse_get_req(fc, 1);
1340         if (IS_ERR(req))
1341                 return PTR_ERR(req);
1342 
1343         page = alloc_page(GFP_KERNEL);
1344         if (!page) {
1345                 fuse_put_request(fc, req);
1346                 return -ENOMEM;
1347         }
1348 
1349         plus = fuse_use_readdirplus(inode, ctx);
1350         req->out.argpages = 1;
1351         req->num_pages = 1;
1352         req->pages[0] = page;
1353         req->page_descs[0].length = PAGE_SIZE;
1354         if (plus) {
1355                 attr_version = fuse_get_attr_version(fc);
1356                 fuse_read_fill(req, file, ctx->pos, PAGE_SIZE,
1357                                FUSE_READDIRPLUS);
1358         } else {
1359                 fuse_read_fill(req, file, ctx->pos, PAGE_SIZE,
1360                                FUSE_READDIR);
1361         }
1362         fuse_lock_inode(inode);
1363         fuse_request_send(fc, req);
1364         fuse_unlock_inode(inode);
1365         nbytes = req->out.args[0].size;
1366         err = req->out.h.error;
1367         fuse_put_request(fc, req);
1368         if (!err) {
1369                 if (plus) {
1370                         err = parse_dirplusfile(page_address(page), nbytes,
1371                                                 file, ctx,
1372                                                 attr_version);
1373                 } else {
1374                         err = parse_dirfile(page_address(page), nbytes, file,
1375                                             ctx);
1376                 }
1377         }
1378 
1379         __free_page(page);
1380         fuse_invalidate_atime(inode);
1381         return err;
1382 }
1383 
1384 static const char *fuse_get_link(struct dentry *dentry,
1385                                  struct inode *inode,
1386                                  struct delayed_call *done)
1387 {
1388         struct fuse_conn *fc = get_fuse_conn(inode);
1389         FUSE_ARGS(args);
1390         char *link;
1391         ssize_t ret;
1392 
1393         if (!dentry)
1394                 return ERR_PTR(-ECHILD);
1395 
1396         link = kmalloc(PAGE_SIZE, GFP_KERNEL);
1397         if (!link)
1398                 return ERR_PTR(-ENOMEM);
1399 
1400         args.in.h.opcode = FUSE_READLINK;
1401         args.in.h.nodeid = get_node_id(inode);
1402         args.out.argvar = 1;
1403         args.out.numargs = 1;
1404         args.out.args[0].size = PAGE_SIZE - 1;
1405         args.out.args[0].value = link;
1406         ret = fuse_simple_request(fc, &args);
1407         if (ret < 0) {
1408                 kfree(link);
1409                 link = ERR_PTR(ret);
1410         } else {
1411                 link[ret] = '\0';
1412                 set_delayed_call(done, kfree_link, link);
1413         }
1414         fuse_invalidate_atime(inode);
1415         return link;
1416 }
1417 
1418 static int fuse_dir_open(struct inode *inode, struct file *file)
1419 {
1420         return fuse_open_common(inode, file, true);
1421 }
1422 
1423 static int fuse_dir_release(struct inode *inode, struct file *file)
1424 {
1425         fuse_release_common(file, FUSE_RELEASEDIR);
1426 
1427         return 0;
1428 }
1429 
1430 static int fuse_dir_fsync(struct file *file, loff_t start, loff_t end,
1431                           int datasync)
1432 {
1433         return fuse_fsync_common(file, start, end, datasync, 1);
1434 }
1435 
1436 static long fuse_dir_ioctl(struct file *file, unsigned int cmd,
1437                             unsigned long arg)
1438 {
1439         struct fuse_conn *fc = get_fuse_conn(file->f_mapping->host);
1440 
1441         /* FUSE_IOCTL_DIR only supported for API version >= 7.18 */
1442         if (fc->minor < 18)
1443                 return -ENOTTY;
1444 
1445         return fuse_ioctl_common(file, cmd, arg, FUSE_IOCTL_DIR);
1446 }
1447 
1448 static long fuse_dir_compat_ioctl(struct file *file, unsigned int cmd,
1449                                    unsigned long arg)
1450 {
1451         struct fuse_conn *fc = get_fuse_conn(file->f_mapping->host);
1452 
1453         if (fc->minor < 18)
1454                 return -ENOTTY;
1455 
1456         return fuse_ioctl_common(file, cmd, arg,
1457                                  FUSE_IOCTL_COMPAT | FUSE_IOCTL_DIR);
1458 }
1459 
1460 static bool update_mtime(unsigned ivalid, bool trust_local_mtime)
1461 {
1462         /* Always update if mtime is explicitly set  */
1463         if (ivalid & ATTR_MTIME_SET)
1464                 return true;
1465 
1466         /* Or if kernel i_mtime is the official one */
1467         if (trust_local_mtime)
1468                 return true;
1469 
1470         /* If it's an open(O_TRUNC) or an ftruncate(), don't update */
1471         if ((ivalid & ATTR_SIZE) && (ivalid & (ATTR_OPEN | ATTR_FILE)))
1472                 return false;
1473 
1474         /* In all other cases update */
1475         return true;
1476 }
1477 
1478 static void iattr_to_fattr(struct iattr *iattr, struct fuse_setattr_in *arg,
1479                            bool trust_local_cmtime)
1480 {
1481         unsigned ivalid = iattr->ia_valid;
1482 
1483         if (ivalid & ATTR_MODE)
1484                 arg->valid |= FATTR_MODE,   arg->mode = iattr->ia_mode;
1485         if (ivalid & ATTR_UID)
1486                 arg->valid |= FATTR_UID,    arg->uid = from_kuid(&init_user_ns, iattr->ia_uid);
1487         if (ivalid & ATTR_GID)
1488                 arg->valid |= FATTR_GID,    arg->gid = from_kgid(&init_user_ns, iattr->ia_gid);
1489         if (ivalid & ATTR_SIZE)
1490                 arg->valid |= FATTR_SIZE,   arg->size = iattr->ia_size;
1491         if (ivalid & ATTR_ATIME) {
1492                 arg->valid |= FATTR_ATIME;
1493                 arg->atime = iattr->ia_atime.tv_sec;
1494                 arg->atimensec = iattr->ia_atime.tv_nsec;
1495                 if (!(ivalid & ATTR_ATIME_SET))
1496                         arg->valid |= FATTR_ATIME_NOW;
1497         }
1498         if ((ivalid & ATTR_MTIME) && update_mtime(ivalid, trust_local_cmtime)) {
1499                 arg->valid |= FATTR_MTIME;
1500                 arg->mtime = iattr->ia_mtime.tv_sec;
1501                 arg->mtimensec = iattr->ia_mtime.tv_nsec;
1502                 if (!(ivalid & ATTR_MTIME_SET) && !trust_local_cmtime)
1503                         arg->valid |= FATTR_MTIME_NOW;
1504         }
1505         if ((ivalid & ATTR_CTIME) && trust_local_cmtime) {
1506                 arg->valid |= FATTR_CTIME;
1507                 arg->ctime = iattr->ia_ctime.tv_sec;
1508                 arg->ctimensec = iattr->ia_ctime.tv_nsec;
1509         }
1510 }
1511 
1512 /*
1513  * Prevent concurrent writepages on inode
1514  *
1515  * This is done by adding a negative bias to the inode write counter
1516  * and waiting for all pending writes to finish.
1517  */
1518 void fuse_set_nowrite(struct inode *inode)
1519 {
1520         struct fuse_conn *fc = get_fuse_conn(inode);
1521         struct fuse_inode *fi = get_fuse_inode(inode);
1522 
1523         BUG_ON(!inode_is_locked(inode));
1524 
1525         spin_lock(&fc->lock);
1526         BUG_ON(fi->writectr < 0);
1527         fi->writectr += FUSE_NOWRITE;
1528         spin_unlock(&fc->lock);
1529         wait_event(fi->page_waitq, fi->writectr == FUSE_NOWRITE);
1530 }
1531 
1532 /*
1533  * Allow writepages on inode
1534  *
1535  * Remove the bias from the writecounter and send any queued
1536  * writepages.
1537  */
1538 static void __fuse_release_nowrite(struct inode *inode)
1539 {
1540         struct fuse_inode *fi = get_fuse_inode(inode);
1541 
1542         BUG_ON(fi->writectr != FUSE_NOWRITE);
1543         fi->writectr = 0;
1544         fuse_flush_writepages(inode);
1545 }
1546 
1547 void fuse_release_nowrite(struct inode *inode)
1548 {
1549         struct fuse_conn *fc = get_fuse_conn(inode);
1550 
1551         spin_lock(&fc->lock);
1552         __fuse_release_nowrite(inode);
1553         spin_unlock(&fc->lock);
1554 }
1555 
1556 static void fuse_setattr_fill(struct fuse_conn *fc, struct fuse_args *args,
1557                               struct inode *inode,
1558                               struct fuse_setattr_in *inarg_p,
1559                               struct fuse_attr_out *outarg_p)
1560 {
1561         args->in.h.opcode = FUSE_SETATTR;
1562         args->in.h.nodeid = get_node_id(inode);
1563         args->in.numargs = 1;
1564         args->in.args[0].size = sizeof(*inarg_p);
1565         args->in.args[0].value = inarg_p;
1566         args->out.numargs = 1;
1567         args->out.args[0].size = sizeof(*outarg_p);
1568         args->out.args[0].value = outarg_p;
1569 }
1570 
1571 /*
1572  * Flush inode->i_mtime to the server
1573  */
1574 int fuse_flush_times(struct inode *inode, struct fuse_file *ff)
1575 {
1576         struct fuse_conn *fc = get_fuse_conn(inode);
1577         FUSE_ARGS(args);
1578         struct fuse_setattr_in inarg;
1579         struct fuse_attr_out outarg;
1580 
1581         memset(&inarg, 0, sizeof(inarg));
1582         memset(&outarg, 0, sizeof(outarg));
1583 
1584         inarg.valid = FATTR_MTIME;
1585         inarg.mtime = inode->i_mtime.tv_sec;
1586         inarg.mtimensec = inode->i_mtime.tv_nsec;
1587         if (fc->minor >= 23) {
1588                 inarg.valid |= FATTR_CTIME;
1589                 inarg.ctime = inode->i_ctime.tv_sec;
1590                 inarg.ctimensec = inode->i_ctime.tv_nsec;
1591         }
1592         if (ff) {
1593                 inarg.valid |= FATTR_FH;
1594                 inarg.fh = ff->fh;
1595         }
1596         fuse_setattr_fill(fc, &args, inode, &inarg, &outarg);
1597 
1598         return fuse_simple_request(fc, &args);
1599 }
1600 
1601 /*
1602  * Set attributes, and at the same time refresh them.
1603  *
1604  * Truncation is slightly complicated, because the 'truncate' request
1605  * may fail, in which case we don't want to touch the mapping.
1606  * vmtruncate() doesn't allow for this case, so do the rlimit checking
1607  * and the actual truncation by hand.
1608  */
1609 int fuse_do_setattr(struct dentry *dentry, struct iattr *attr,
1610                     struct file *file)
1611 {
1612         struct inode *inode = d_inode(dentry);
1613         struct fuse_conn *fc = get_fuse_conn(inode);
1614         struct fuse_inode *fi = get_fuse_inode(inode);
1615         FUSE_ARGS(args);
1616         struct fuse_setattr_in inarg;
1617         struct fuse_attr_out outarg;
1618         bool is_truncate = false;
1619         bool is_wb = fc->writeback_cache;
1620         loff_t oldsize;
1621         int err;
1622         bool trust_local_cmtime = is_wb && S_ISREG(inode->i_mode);
1623 
1624         if (!fc->default_permissions)
1625                 attr->ia_valid |= ATTR_FORCE;
1626 
1627         err = setattr_prepare(dentry, attr);
1628         if (err)
1629                 return err;
1630 
1631         if (attr->ia_valid & ATTR_OPEN) {
1632                 if (fc->atomic_o_trunc)
1633                         return 0;
1634                 file = NULL;
1635         }
1636 
1637         if (attr->ia_valid & ATTR_SIZE)
1638                 is_truncate = true;
1639 
1640         if (is_truncate) {
1641                 fuse_set_nowrite(inode);
1642                 set_bit(FUSE_I_SIZE_UNSTABLE, &fi->state);
1643                 if (trust_local_cmtime && attr->ia_size != inode->i_size)
1644                         attr->ia_valid |= ATTR_MTIME | ATTR_CTIME;
1645         }
1646 
1647         memset(&inarg, 0, sizeof(inarg));
1648         memset(&outarg, 0, sizeof(outarg));
1649         iattr_to_fattr(attr, &inarg, trust_local_cmtime);
1650         if (file) {
1651                 struct fuse_file *ff = file->private_data;
1652                 inarg.valid |= FATTR_FH;
1653                 inarg.fh = ff->fh;
1654         }
1655         if (attr->ia_valid & ATTR_SIZE) {
1656                 /* For mandatory locking in truncate */
1657                 inarg.valid |= FATTR_LOCKOWNER;
1658                 inarg.lock_owner = fuse_lock_owner_id(fc, current->files);
1659         }
1660         fuse_setattr_fill(fc, &args, inode, &inarg, &outarg);
1661         err = fuse_simple_request(fc, &args);
1662         if (err) {
1663                 if (err == -EINTR)
1664                         fuse_invalidate_attr(inode);
1665                 goto error;
1666         }
1667 
1668         if ((inode->i_mode ^ outarg.attr.mode) & S_IFMT) {
1669                 make_bad_inode(inode);
1670                 err = -EIO;
1671                 goto error;
1672         }
1673 
1674         spin_lock(&fc->lock);
1675         /* the kernel maintains i_mtime locally */
1676         if (trust_local_cmtime) {
1677                 if (attr->ia_valid & ATTR_MTIME)
1678                         inode->i_mtime = attr->ia_mtime;
1679                 if (attr->ia_valid & ATTR_CTIME)
1680                         inode->i_ctime = attr->ia_ctime;
1681                 /* FIXME: clear I_DIRTY_SYNC? */
1682         }
1683 
1684         fuse_change_attributes_common(inode, &outarg.attr,
1685                                       attr_timeout(&outarg));
1686         oldsize = inode->i_size;
1687         /* see the comment in fuse_change_attributes() */
1688         if (!is_wb || is_truncate || !S_ISREG(inode->i_mode))
1689                 i_size_write(inode, outarg.attr.size);
1690 
1691         if (is_truncate) {
1692                 /* NOTE: this may release/reacquire fc->lock */
1693                 __fuse_release_nowrite(inode);
1694         }
1695         spin_unlock(&fc->lock);
1696 
1697         /*
1698          * Only call invalidate_inode_pages2() after removing
1699          * FUSE_NOWRITE, otherwise fuse_launder_page() would deadlock.
1700          */
1701         if ((is_truncate || !is_wb) &&
1702             S_ISREG(inode->i_mode) && oldsize != outarg.attr.size) {
1703                 truncate_pagecache(inode, outarg.attr.size);
1704                 invalidate_inode_pages2(inode->i_mapping);
1705         }
1706 
1707         clear_bit(FUSE_I_SIZE_UNSTABLE, &fi->state);
1708         return 0;
1709 
1710 error:
1711         if (is_truncate)
1712                 fuse_release_nowrite(inode);
1713 
1714         clear_bit(FUSE_I_SIZE_UNSTABLE, &fi->state);
1715         return err;
1716 }
1717 
1718 static int fuse_setattr(struct dentry *entry, struct iattr *attr)
1719 {
1720         struct inode *inode = d_inode(entry);
1721         struct fuse_conn *fc = get_fuse_conn(inode);
1722         struct file *file = (attr->ia_valid & ATTR_FILE) ? attr->ia_file : NULL;
1723         int ret;
1724 
1725         if (!fuse_allow_current_process(get_fuse_conn(inode)))
1726                 return -EACCES;
1727 
1728         if (attr->ia_valid & (ATTR_KILL_SUID | ATTR_KILL_SGID)) {
1729                 attr->ia_valid &= ~(ATTR_KILL_SUID | ATTR_KILL_SGID |
1730                                     ATTR_MODE);
1731 
1732                 /*
1733                  * The only sane way to reliably kill suid/sgid is to do it in
1734                  * the userspace filesystem
1735                  *
1736                  * This should be done on write(), truncate() and chown().
1737                  */
1738                 if (!fc->handle_killpriv) {
1739                         /*
1740                          * ia_mode calculation may have used stale i_mode.
1741                          * Refresh and recalculate.
1742                          */
1743                         ret = fuse_do_getattr(inode, NULL, file);
1744                         if (ret)
1745                                 return ret;
1746 
1747                         attr->ia_mode = inode->i_mode;
1748                         if (inode->i_mode & S_ISUID) {
1749                                 attr->ia_valid |= ATTR_MODE;
1750                                 attr->ia_mode &= ~S_ISUID;
1751                         }
1752                         if ((inode->i_mode & (S_ISGID | S_IXGRP)) == (S_ISGID | S_IXGRP)) {
1753                                 attr->ia_valid |= ATTR_MODE;
1754                                 attr->ia_mode &= ~S_ISGID;
1755                         }
1756                 }
1757         }
1758         if (!attr->ia_valid)
1759                 return 0;
1760 
1761         ret = fuse_do_setattr(entry, attr, file);
1762         if (!ret) {
1763                 /*
1764                  * If filesystem supports acls it may have updated acl xattrs in
1765                  * the filesystem, so forget cached acls for the inode.
1766                  */
1767                 if (fc->posix_acl)
1768                         forget_all_cached_acls(inode);
1769 
1770                 /* Directory mode changed, may need to revalidate access */
1771                 if (d_is_dir(entry) && (attr->ia_valid & ATTR_MODE))
1772                         fuse_invalidate_entry_cache(entry);
1773         }
1774         return ret;
1775 }
1776 
1777 static int fuse_getattr(const struct path *path, struct kstat *stat,
1778                         u32 request_mask, unsigned int flags)
1779 {
1780         struct inode *inode = d_inode(path->dentry);
1781         struct fuse_conn *fc = get_fuse_conn(inode);
1782 
1783         if (!fuse_allow_current_process(fc))
1784                 return -EACCES;
1785 
1786         return fuse_update_get_attr(inode, NULL, stat);
1787 }
1788 
1789 static const struct inode_operations fuse_dir_inode_operations = {
1790         .lookup         = fuse_lookup,
1791         .mkdir          = fuse_mkdir,
1792         .symlink        = fuse_symlink,
1793         .unlink         = fuse_unlink,
1794         .rmdir          = fuse_rmdir,
1795         .rename         = fuse_rename2,
1796         .link           = fuse_link,
1797         .setattr        = fuse_setattr,
1798         .create         = fuse_create,
1799         .atomic_open    = fuse_atomic_open,
1800         .mknod          = fuse_mknod,
1801         .permission     = fuse_permission,
1802         .getattr        = fuse_getattr,
1803         .listxattr      = fuse_listxattr,
1804         .get_acl        = fuse_get_acl,
1805         .set_acl        = fuse_set_acl,
1806 };
1807 
1808 static const struct file_operations fuse_dir_operations = {
1809         .llseek         = generic_file_llseek,
1810         .read           = generic_read_dir,
1811         .iterate_shared = fuse_readdir,
1812         .open           = fuse_dir_open,
1813         .release        = fuse_dir_release,
1814         .fsync          = fuse_dir_fsync,
1815         .unlocked_ioctl = fuse_dir_ioctl,
1816         .compat_ioctl   = fuse_dir_compat_ioctl,
1817 };
1818 
1819 static const struct inode_operations fuse_common_inode_operations = {
1820         .setattr        = fuse_setattr,
1821         .permission     = fuse_permission,
1822         .getattr        = fuse_getattr,
1823         .listxattr      = fuse_listxattr,
1824         .get_acl        = fuse_get_acl,
1825         .set_acl        = fuse_set_acl,
1826 };
1827 
1828 static const struct inode_operations fuse_symlink_inode_operations = {
1829         .setattr        = fuse_setattr,
1830         .get_link       = fuse_get_link,
1831         .getattr        = fuse_getattr,
1832         .listxattr      = fuse_listxattr,
1833 };
1834 
1835 void fuse_init_common(struct inode *inode)
1836 {
1837         inode->i_op = &fuse_common_inode_operations;
1838 }
1839 
1840 void fuse_init_dir(struct inode *inode)
1841 {
1842         inode->i_op = &fuse_dir_inode_operations;
1843         inode->i_fop = &fuse_dir_operations;
1844 }
1845 
1846 void fuse_init_symlink(struct inode *inode)
1847 {
1848         inode->i_op = &fuse_symlink_inode_operations;
1849 }
1850 

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