fs/fuse/dir.c

   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 static bool fuse_use_readdirplus(struct inode *dir, struct dir_context *ctx)
  18 {
  19         struct fuse_conn *fc = get_fuse_conn(dir);
  20         struct fuse_inode *fi = get_fuse_inode(dir);
  21
  22         if (!fc->do_readdirplus)
  23                 return false;
  24         if (!fc->readdirplus_auto)
  25                 return true;
  26         if (test_and_clear_bit(FUSE_I_ADVISE_RDPLUS, &fi->state))
  27                 return true;
  28         if (ctx->pos == 0)
  29                 return true;
  30         return false;
  31 }
  32
  33 static void fuse_advise_use_readdirplus(struct inode *dir)
  34 {
  35         struct fuse_inode *fi = get_fuse_inode(dir);
  36
  37         set_bit(FUSE_I_ADVISE_RDPLUS, &fi->state);
  38 }
  39
  40 #if BITS_PER_LONG >= 64
  41 static inline void fuse_dentry_settime(struct dentry *entry, u64 time)
  42 {
  43         entry->d_time = time;
  44 }
  45
  46 static inline u64 fuse_dentry_time(struct dentry *entry)
  47 {
  48         return entry->d_time;
  49 }
  50 #else
  51 /*
  52  * On 32 bit archs store the high 32 bits of time in d_fsdata
  53  */
  54 static void fuse_dentry_settime(struct dentry *entry, u64 time)
  55 {
  56         entry->d_time = time;
  57         entry->d_fsdata = (void *) (unsigned long) (time >> 32);
  58 }
  59
  60 static u64 fuse_dentry_time(struct dentry *entry)
  61 {
  62         return (u64) entry->d_time +
  63                 ((u64) (unsigned long) entry->d_fsdata << 32);
  64 }
  65 #endif
  66
  67 /*
  68  * FUSE caches dentries and attributes with separate timeout.  The
  69  * time in jiffies until the dentry/attributes are valid is stored in
  70  * dentry->d_time and fuse_inode->i_time respectively.
  71  */
  72
  73 /*
  74  * Calculate the time in jiffies until a dentry/attributes are valid
  75  */
  76 static u64 time_to_jiffies(unsigned long sec, unsigned long nsec)
  77 {
  78         if (sec || nsec) {
  79                 struct timespec ts = {sec, nsec};
  80                 return get_jiffies_64() + timespec_to_jiffies(&ts);
  81         } else
  82                 return 0;
  83 }
  84
  85 /*
  86  * Set dentry and possibly attribute timeouts from the lookup/mk*
  87  * replies
  88  */
  89 static void fuse_change_entry_timeout(struct dentry *entry,
  90                                       struct fuse_entry_out *o)
  91 {
  92         fuse_dentry_settime(entry,
  93                 time_to_jiffies(o->entry_valid, o->entry_valid_nsec));
  94 }
  95
  96 static u64 attr_timeout(struct fuse_attr_out *o)
  97 {
  98         return time_to_jiffies(o->attr_valid, o->attr_valid_nsec);
  99 }
 100
 101 static u64 entry_attr_timeout(struct fuse_entry_out *o)
 102 {
 103         return time_to_jiffies(o->attr_valid, o->attr_valid_nsec);
 104 }
 105
 106 /*
 107  * Mark the attributes as stale, so that at the next call to
 108  * ->getattr() they will be fetched from userspace
 109  */
 110 void fuse_invalidate_attr(struct inode *inode)
 111 {
 112         get_fuse_inode(inode)->i_time = 0;
 113 }
 114
 115 /**
 116  * Mark the attributes as stale due to an atime change.  Avoid the invalidate if
 117  * atime is not used.
 118  */
 119 void fuse_invalidate_atime(struct inode *inode)
 120 {
 121         if (!IS_RDONLY(inode))
 122                 fuse_invalidate_attr(inode);
 123 }
 124
 125 /*
 126  * Just mark the entry as stale, so that a next attempt to look it up
 127  * will result in a new lookup call to userspace
 128  *
 129  * This is called when a dentry is about to become negative and the
 130  * timeout is unknown (unlink, rmdir, rename and in some cases
 131  * lookup)
 132  */
 133 void fuse_invalidate_entry_cache(struct dentry *entry)
 134 {
 135         fuse_dentry_settime(entry, 0);
 136 }
 137
 138 /*
 139  * Same as fuse_invalidate_entry_cache(), but also try to remove the
 140  * dentry from the hash
 141  */
 142 static void fuse_invalidate_entry(struct dentry *entry)
 143 {
 144         d_invalidate(entry);
 145         fuse_invalidate_entry_cache(entry);
 146 }
 147
 148 static void fuse_lookup_init(struct fuse_conn *fc, struct fuse_req *req,
 149                              u64 nodeid, struct qstr *name,
 150                              struct fuse_entry_out *outarg)
 151 {
 152         memset(outarg, 0, sizeof(struct fuse_entry_out));
 153         req->in.h.opcode = FUSE_LOOKUP;
 154         req->in.h.nodeid = nodeid;
 155         req->in.numargs = 1;
 156         req->in.args[0].size = name->len + 1;
 157         req->in.args[0].value = name->name;
 158         req->out.numargs = 1;
 159         if (fc->minor < 9)
 160                 req->out.args[0].size = FUSE_COMPAT_ENTRY_OUT_SIZE;
 161         else
 162                 req->out.args[0].size = sizeof(struct fuse_entry_out);
 163         req->out.args[0].value = outarg;
 164 }
 165
 166 u64 fuse_get_attr_version(struct fuse_conn *fc)
 167 {
 168         u64 curr_version;
 169
 170         /*
 171          * The spin lock isn't actually needed on 64bit archs, but we
 172          * don't yet care too much about such optimizations.
 173          */
 174         spin_lock(&fc->lock);
 175         curr_version = fc->attr_version;
 176         spin_unlock(&fc->lock);
 177
 178         return curr_version;
 179 }
 180
 181 /*
 182  * Check whether the dentry is still valid
 183  *
 184  * If the entry validity timeout has expired and the dentry is
 185  * positive, try to redo the lookup.  If the lookup results in a
 186  * different inode, then let the VFS invalidate the dentry and redo
 187  * the lookup once more.  If the lookup results in the same inode,
 188  * then refresh the attributes, timeouts and mark the dentry valid.
 189  */
 190 static int fuse_dentry_revalidate(struct dentry *entry, unsigned int flags)
 191 {
 192         struct inode *inode;
 193         struct dentry *parent;
 194         struct fuse_conn *fc;
 195         struct fuse_inode *fi;
 196         int ret;
 197
 198         inode = ACCESS_ONCE(entry->d_inode);
 199         if (inode && is_bad_inode(inode))
 200                 goto invalid;
 201         else if (time_before64(fuse_dentry_time(entry), get_jiffies_64()) ||
 202                  (flags & LOOKUP_REVAL)) {
 203                 int err;
 204                 struct fuse_entry_out outarg;
 205                 struct fuse_req *req;
 206                 struct fuse_forget_link *forget;
 207                 u64 attr_version;
 208
 209                 /* For negative dentries, always do a fresh lookup */
 210                 if (!inode)
 211                         goto invalid;
 212
 213                 ret = -ECHILD;
 214                 if (flags & LOOKUP_RCU)
 215                         goto out;
 216
 217                 fc = get_fuse_conn(inode);
 218                 req = fuse_get_req_nopages(fc);
 219                 ret = PTR_ERR(req);
 220                 if (IS_ERR(req))
 221                         goto out;
 222
 223                 forget = fuse_alloc_forget();
 224                 if (!forget) {
 225                         fuse_put_request(fc, req);
 226                         ret = -ENOMEM;
 227                         goto out;
 228                 }
 229
 230                 attr_version = fuse_get_attr_version(fc);
 231
 232                 parent = dget_parent(entry);
 233                 fuse_lookup_init(fc, req, get_node_id(parent->d_inode),
 234                                  &entry->d_name, &outarg);
 235                 fuse_request_send(fc, req);
 236                 dput(parent);
 237                 err = req->out.h.error;
 238                 fuse_put_request(fc, req);
 239                 /* Zero nodeid is same as -ENOENT */
 240                 if (!err && !outarg.nodeid)
 241                         err = -ENOENT;
 242                 if (!err) {
 243                         fi = get_fuse_inode(inode);
 244                         if (outarg.nodeid != get_node_id(inode)) {
 245                                 fuse_queue_forget(fc, forget, outarg.nodeid, 1);
 246                                 goto invalid;
 247                         }
 248                         spin_lock(&fc->lock);
 249                         fi->nlookup++;
 250                         spin_unlock(&fc->lock);
 251                 }
 252                 kfree(forget);
 253                 if (err || (outarg.attr.mode ^ inode->i_mode) & S_IFMT)
 254                         goto invalid;
 255
 256                 fuse_change_attributes(inode, &outarg.attr,
 257                                        entry_attr_timeout(&outarg),
 258                                        attr_version);
 259                 fuse_change_entry_timeout(entry, &outarg);
 260         } else if (inode) {
 261                 fi = get_fuse_inode(inode);
 262                 if (flags & LOOKUP_RCU) {
 263                         if (test_bit(FUSE_I_INIT_RDPLUS, &fi->state))
 264                                 return -ECHILD;
 265                 } else if (test_and_clear_bit(FUSE_I_INIT_RDPLUS, &fi->state)) {
 266                         parent = dget_parent(entry);
 267                         fuse_advise_use_readdirplus(parent->d_inode);
 268                         dput(parent);
 269                 }
 270         }
 271         ret = 1;
 272 out:
 273         return ret;
 274
 275 invalid:
 276         ret = 0;
 277
 278         if (!(flags & LOOKUP_RCU) && check_submounts_and_drop(entry) != 0)
 279                 ret = 1;
 280         goto out;
 281 }
 282
 283 static int invalid_nodeid(u64 nodeid)
 284 {
 285         return !nodeid || nodeid == FUSE_ROOT_ID;
 286 }
 287
 288 const struct dentry_operations fuse_dentry_operations = {
 289         .d_revalidate   = fuse_dentry_revalidate,
 290 };
 291
 292 int fuse_valid_type(int m)
 293 {
 294         return S_ISREG(m) || S_ISDIR(m) || S_ISLNK(m) || S_ISCHR(m) ||
 295                 S_ISBLK(m) || S_ISFIFO(m) || S_ISSOCK(m);
 296 }
 297
 298 int fuse_lookup_name(struct super_block *sb, u64 nodeid, struct qstr *name,
 299                      struct fuse_entry_out *outarg, struct inode **inode)
 300 {
 301         struct fuse_conn *fc = get_fuse_conn_super(sb);
 302         struct fuse_req *req;
 303         struct fuse_forget_link *forget;
 304         u64 attr_version;
 305         int err;
 306
 307         *inode = NULL;
 308         err = -ENAMETOOLONG;
 309         if (name->len > FUSE_NAME_MAX)
 310                 goto out;
 311
 312         req = fuse_get_req_nopages(fc);
 313         err = PTR_ERR(req);
 314         if (IS_ERR(req))
 315                 goto out;
 316
 317         forget = fuse_alloc_forget();
 318         err = -ENOMEM;
 319         if (!forget) {
 320                 fuse_put_request(fc, req);
 321                 goto out;
 322         }
 323
 324         attr_version = fuse_get_attr_version(fc);
 325
 326         fuse_lookup_init(fc, req, nodeid, name, outarg);
 327         fuse_request_send(fc, req);
 328         err = req->out.h.error;
 329         fuse_put_request(fc, req);
 330         /* Zero nodeid is same as -ENOENT, but with valid timeout */
 331         if (err || !outarg->nodeid)
 332                 goto out_put_forget;
 333
 334         err = -EIO;
 335         if (!outarg->nodeid)
 336                 goto out_put_forget;
 337         if (!fuse_valid_type(outarg->attr.mode))
 338                 goto out_put_forget;
 339
 340         *inode = fuse_iget(sb, outarg->nodeid, outarg->generation,
 341                            &outarg->attr, entry_attr_timeout(outarg),
 342                            attr_version);
 343         err = -ENOMEM;
 344         if (!*inode) {
 345                 fuse_queue_forget(fc, forget, outarg->nodeid, 1);
 346                 goto out;
 347         }
 348         err = 0;
 349
 350  out_put_forget:
 351         kfree(forget);
 352  out:
 353         return err;
 354 }
 355
 356 static struct dentry *fuse_lookup(struct inode *dir, struct dentry *entry,
 357                                   unsigned int flags)
 358 {
 359         int err;
 360         struct fuse_entry_out outarg;
 361         struct inode *inode;
 362         struct dentry *newent;
 363         bool outarg_valid = true;
 364
 365         err = fuse_lookup_name(dir->i_sb, get_node_id(dir), &entry->d_name,
 366                                &outarg, &inode);
 367         if (err == -ENOENT) {
 368                 outarg_valid = false;
 369                 err = 0;
 370         }
 371         if (err)
 372                 goto out_err;
 373
 374         err = -EIO;
 375         if (inode && get_node_id(inode) == FUSE_ROOT_ID)
 376                 goto out_iput;
 377
 378         newent = d_materialise_unique(entry, inode);
 379         err = PTR_ERR(newent);
 380         if (IS_ERR(newent))
 381                 goto out_err;
 382
 383         entry = newent ? newent : entry;
 384         if (outarg_valid)
 385                 fuse_change_entry_timeout(entry, &outarg);
 386         else
 387                 fuse_invalidate_entry_cache(entry);
 388
 389         fuse_advise_use_readdirplus(dir);
 390         return newent;
 391
 392  out_iput:
 393         iput(inode);
 394  out_err:
 395         return ERR_PTR(err);
 396 }
 397
 398 /*
 399  * Atomic create+open operation
 400  *
 401  * If the filesystem doesn't support this, then fall back to separate
 402  * 'mknod' + 'open' requests.
 403  */
 404 static int fuse_create_open(struct inode *dir, struct dentry *entry,
 405                             struct file *file, unsigned flags,
 406                             umode_t mode, int *opened)
 407 {
 408         int err;
 409         struct inode *inode;
 410         struct fuse_conn *fc = get_fuse_conn(dir);
 411         struct fuse_req *req;
 412         struct fuse_forget_link *forget;
 413         struct fuse_create_in inarg;
 414         struct fuse_open_out outopen;
 415         struct fuse_entry_out outentry;
 416         struct fuse_file *ff;
 417
 418         /* Userspace expects S_IFREG in create mode */
 419         BUG_ON((mode & S_IFMT) != S_IFREG);
 420
 421         forget = fuse_alloc_forget();
 422         err = -ENOMEM;
 423         if (!forget)
 424                 goto out_err;
 425
 426         req = fuse_get_req_nopages(fc);
 427         err = PTR_ERR(req);
 428         if (IS_ERR(req))
 429                 goto out_put_forget_req;
 430
 431         err = -ENOMEM;
 432         ff = fuse_file_alloc(fc);
 433         if (!ff)
 434                 goto out_put_request;
 435
 436         if (!fc->dont_mask)
 437                 mode &= ~current_umask();
 438
 439         flags &= ~O_NOCTTY;
 440         memset(&inarg, 0, sizeof(inarg));
 441         memset(&outentry, 0, sizeof(outentry));
 442         inarg.flags = flags;
 443         inarg.mode = mode;
 444         inarg.umask = current_umask();
 445         req->in.h.opcode = FUSE_CREATE;
 446         req->in.h.nodeid = get_node_id(dir);
 447         req->in.numargs = 2;
 448         req->in.args[0].size = fc->minor < 12 ? sizeof(struct fuse_open_in) :
 449                                                 sizeof(inarg);
 450         req->in.args[0].value = &inarg;
 451         req->in.args[1].size = entry->d_name.len + 1;
 452         req->in.args[1].value = entry->d_name.name;
 453         req->out.numargs = 2;
 454         if (fc->minor < 9)
 455                 req->out.args[0].size = FUSE_COMPAT_ENTRY_OUT_SIZE;
 456         else
 457                 req->out.args[0].size = sizeof(outentry);
 458         req->out.args[0].value = &outentry;
 459         req->out.args[1].size = sizeof(outopen);
 460         req->out.args[1].value = &outopen;
 461         fuse_request_send(fc, req);
 462         err = req->out.h.error;
 463         if (err)
 464                 goto out_free_ff;
 465
 466         err = -EIO;
 467         if (!S_ISREG(outentry.attr.mode) || invalid_nodeid(outentry.nodeid))
 468                 goto out_free_ff;
 469
 470         fuse_put_request(fc, req);
 471         ff->fh = outopen.fh;
 472         ff->nodeid = outentry.nodeid;
 473         ff->open_flags = outopen.open_flags;
 474         inode = fuse_iget(dir->i_sb, outentry.nodeid, outentry.generation,
 475                           &outentry.attr, entry_attr_timeout(&outentry), 0);
 476         if (!inode) {
 477                 flags &= ~(O_CREAT | O_EXCL | O_TRUNC);
 478                 fuse_sync_release(ff, flags);
 479                 fuse_queue_forget(fc, forget, outentry.nodeid, 1);
 480                 err = -ENOMEM;
 481                 goto out_err;
 482         }
 483         kfree(forget);
 484         d_instantiate(entry, inode);
 485         fuse_change_entry_timeout(entry, &outentry);
 486         fuse_invalidate_attr(dir);
 487         err = finish_open(file, entry, generic_file_open, opened);
 488         if (err) {
 489                 fuse_sync_release(ff, flags);
 490         } else {
 491                 file->private_data = fuse_file_get(ff);
 492                 fuse_finish_open(inode, file);
 493         }
 494         return err;
 495
 496 out_free_ff:
 497         fuse_file_free(ff);
 498 out_put_request:
 499         fuse_put_request(fc, req);
 500 out_put_forget_req:
 501         kfree(forget);
 502 out_err:
 503         return err;
 504 }
 505
 506 static int fuse_mknod(struct inode *, struct dentry *, umode_t, dev_t);
 507 static int fuse_atomic_open(struct inode *dir, struct dentry *entry,
 508                             struct file *file, unsigned flags,
 509                             umode_t mode, int *opened)
 510 {
 511         int err;
 512         struct fuse_conn *fc = get_fuse_conn(dir);
 513         struct dentry *res = NULL;
 514
 515         if (d_unhashed(entry)) {
 516                 res = fuse_lookup(dir, entry, 0);
 517                 if (IS_ERR(res))
 518                         return PTR_ERR(res);
 519
 520                 if (res)
 521                         entry = res;
 522         }
 523
 524         if (!(flags & O_CREAT) || entry->d_inode)
 525                 goto no_open;
 526
 527         /* Only creates */
 528         *opened |= FILE_CREATED;
 529
 530         if (fc->no_create)
 531                 goto mknod;
 532
 533         err = fuse_create_open(dir, entry, file, flags, mode, opened);
 534         if (err == -ENOSYS) {
 535                 fc->no_create = 1;
 536                 goto mknod;
 537         }
 538 out_dput:
 539         dput(res);
 540         return err;
 541
 542 mknod:
 543         err = fuse_mknod(dir, entry, mode, 0);
 544         if (err)
 545                 goto out_dput;
 546 no_open:
 547         return finish_no_open(file, res);
 548 }
 549
 550 /*
 551  * Code shared between mknod, mkdir, symlink and link
 552  */
 553 static int create_new_entry(struct fuse_conn *fc, struct fuse_req *req,
 554                             struct inode *dir, struct dentry *entry,
 555                             umode_t mode)
 556 {
 557         struct fuse_entry_out outarg;
 558         struct inode *inode;
 559         int err;
 560         struct fuse_forget_link *forget;
 561
 562         forget = fuse_alloc_forget();
 563         if (!forget) {
 564                 fuse_put_request(fc, req);
 565                 return -ENOMEM;
 566         }
 567
 568         memset(&outarg, 0, sizeof(outarg));
 569         req->in.h.nodeid = get_node_id(dir);
 570         req->out.numargs = 1;
 571         if (fc->minor < 9)
 572                 req->out.args[0].size = FUSE_COMPAT_ENTRY_OUT_SIZE;
 573         else
 574                 req->out.args[0].size = sizeof(outarg);
 575         req->out.args[0].value = &outarg;
 576         fuse_request_send(fc, req);
 577         err = req->out.h.error;
 578         fuse_put_request(fc, req);
 579         if (err)
 580                 goto out_put_forget_req;
 581
 582         err = -EIO;
 583         if (invalid_nodeid(outarg.nodeid))
 584                 goto out_put_forget_req;
 585
 586         if ((outarg.attr.mode ^ mode) & S_IFMT)
 587                 goto out_put_forget_req;
 588
 589         inode = fuse_iget(dir->i_sb, outarg.nodeid, outarg.generation,
 590                           &outarg.attr, entry_attr_timeout(&outarg), 0);
 591         if (!inode) {
 592                 fuse_queue_forget(fc, forget, outarg.nodeid, 1);
 593                 return -ENOMEM;
 594         }
 595         kfree(forget);
 596
 597         err = d_instantiate_no_diralias(entry, inode);
 598         if (err)
 599                 return err;
 600
 601         fuse_change_entry_timeout(entry, &outarg);
 602         fuse_invalidate_attr(dir);
 603         return 0;
 604
 605  out_put_forget_req:
 606         kfree(forget);
 607         return err;
 608 }
 609
 610 static int fuse_mknod(struct inode *dir, struct dentry *entry, umode_t mode,
 611                       dev_t rdev)
 612 {
 613         struct fuse_mknod_in inarg;
 614         struct fuse_conn *fc = get_fuse_conn(dir);
 615         struct fuse_req *req = fuse_get_req_nopages(fc);
 616         if (IS_ERR(req))
 617                 return PTR_ERR(req);
 618
 619         if (!fc->dont_mask)
 620                 mode &= ~current_umask();
 621
 622         memset(&inarg, 0, sizeof(inarg));
 623         inarg.mode = mode;
 624         inarg.rdev = new_encode_dev(rdev);
 625         inarg.umask = current_umask();
 626         req->in.h.opcode = FUSE_MKNOD;
 627         req->in.numargs = 2;
 628         req->in.args[0].size = fc->minor < 12 ? FUSE_COMPAT_MKNOD_IN_SIZE :
 629                                                 sizeof(inarg);
 630         req->in.args[0].value = &inarg;
 631         req->in.args[1].size = entry->d_name.len + 1;
 632         req->in.args[1].value = entry->d_name.name;
 633         return create_new_entry(fc, req, dir, entry, mode);
 634 }
 635
 636 static int fuse_create(struct inode *dir, struct dentry *entry, umode_t mode,
 637                        bool excl)
 638 {
 639         return fuse_mknod(dir, entry, mode, 0);
 640 }
 641
 642 static int fuse_mkdir(struct inode *dir, struct dentry *entry, umode_t mode)
 643 {
 644         struct fuse_mkdir_in inarg;
 645         struct fuse_conn *fc = get_fuse_conn(dir);
 646         struct fuse_req *req = fuse_get_req_nopages(fc);
 647         if (IS_ERR(req))
 648                 return PTR_ERR(req);
 649
 650         if (!fc->dont_mask)
 651                 mode &= ~current_umask();
 652
 653         memset(&inarg, 0, sizeof(inarg));
 654         inarg.mode = mode;
 655         inarg.umask = current_umask();
 656         req->in.h.opcode = FUSE_MKDIR;
 657         req->in.numargs = 2;
 658         req->in.args[0].size = sizeof(inarg);
 659         req->in.args[0].value = &inarg;
 660         req->in.args[1].size = entry->d_name.len + 1;
 661         req->in.args[1].value = entry->d_name.name;
 662         return create_new_entry(fc, req, dir, entry, S_IFDIR);
 663 }
 664
 665 static int fuse_symlink(struct inode *dir, struct dentry *entry,
 666                         const char *link)
 667 {
 668         struct fuse_conn *fc = get_fuse_conn(dir);
 669         unsigned len = strlen(link) + 1;
 670         struct fuse_req *req = fuse_get_req_nopages(fc);
 671         if (IS_ERR(req))
 672                 return PTR_ERR(req);
 673
 674         req->in.h.opcode = FUSE_SYMLINK;
 675         req->in.numargs = 2;
 676         req->in.args[0].size = entry->d_name.len + 1;
 677         req->in.args[0].value = entry->d_name.name;
 678         req->in.args[1].size = len;
 679         req->in.args[1].value = link;
 680         return create_new_entry(fc, req, dir, entry, S_IFLNK);
 681 }
 682
 683 static inline void fuse_update_ctime(struct inode *inode)
 684 {
 685         if (!IS_NOCMTIME(inode)) {
 686                 inode->i_ctime = current_fs_time(inode->i_sb);
 687                 mark_inode_dirty_sync(inode);
 688         }
 689 }
 690
 691 static int fuse_unlink(struct inode *dir, struct dentry *entry)
 692 {
 693         int err;
 694         struct fuse_conn *fc = get_fuse_conn(dir);
 695         struct fuse_req *req = fuse_get_req_nopages(fc);
 696         if (IS_ERR(req))
 697                 return PTR_ERR(req);
 698
 699         req->in.h.opcode = FUSE_UNLINK;
 700         req->in.h.nodeid = get_node_id(dir);
 701         req->in.numargs = 1;
 702         req->in.args[0].size = entry->d_name.len + 1;
 703         req->in.args[0].value = entry->d_name.name;
 704         fuse_request_send(fc, req);
 705         err = req->out.h.error;
 706         fuse_put_request(fc, req);
 707         if (!err) {
 708                 struct inode *inode = entry->d_inode;
 709                 struct fuse_inode *fi = get_fuse_inode(inode);
 710
 711                 spin_lock(&fc->lock);
 712                 fi->attr_version = ++fc->attr_version;
 713                 /*
 714                  * If i_nlink == 0 then unlink doesn't make sense, yet this can
 715                  * happen if userspace filesystem is careless.  It would be
 716                  * difficult to enforce correct nlink usage so just ignore this
 717                  * condition here
 718                  */
 719                 if (inode->i_nlink > 0)
 720                         drop_nlink(inode);
 721                 spin_unlock(&fc->lock);
 722                 fuse_invalidate_attr(inode);
 723                 fuse_invalidate_attr(dir);
 724                 fuse_invalidate_entry_cache(entry);
 725                 fuse_update_ctime(inode);
 726         } else if (err == -EINTR)
 727                 fuse_invalidate_entry(entry);
 728         return err;
 729 }
 730
 731 static int fuse_rmdir(struct inode *dir, struct dentry *entry)
 732 {
 733         int err;
 734         struct fuse_conn *fc = get_fuse_conn(dir);
 735         struct fuse_req *req = fuse_get_req_nopages(fc);
 736         if (IS_ERR(req))
 737                 return PTR_ERR(req);
 738
 739         req->in.h.opcode = FUSE_RMDIR;
 740         req->in.h.nodeid = get_node_id(dir);
 741         req->in.numargs = 1;
 742         req->in.args[0].size = entry->d_name.len + 1;
 743         req->in.args[0].value = entry->d_name.name;
 744         fuse_request_send(fc, req);
 745         err = req->out.h.error;
 746         fuse_put_request(fc, req);
 747         if (!err) {
 748                 clear_nlink(entry->d_inode);
 749                 fuse_invalidate_attr(dir);
 750                 fuse_invalidate_entry_cache(entry);
 751         } else if (err == -EINTR)
 752                 fuse_invalidate_entry(entry);
 753         return err;
 754 }
 755
 756 static int fuse_rename_common(struct inode *olddir, struct dentry *oldent,
 757                               struct inode *newdir, struct dentry *newent,
 758                               unsigned int flags, int opcode, size_t argsize)
 759 {
 760         int err;
 761         struct fuse_rename2_in inarg;
 762         struct fuse_conn *fc = get_fuse_conn(olddir);
 763         struct fuse_req *req;
 764
 765         req = fuse_get_req_nopages(fc);
 766         if (IS_ERR(req))
 767                 return PTR_ERR(req);
 768
 769         memset(&inarg, 0, argsize);
 770         inarg.newdir = get_node_id(newdir);
 771         inarg.flags = flags;
 772         req->in.h.opcode = opcode;
 773         req->in.h.nodeid = get_node_id(olddir);
 774         req->in.numargs = 3;
 775         req->in.args[0].size = argsize;
 776         req->in.args[0].value = &inarg;
 777         req->in.args[1].size = oldent->d_name.len + 1;
 778         req->in.args[1].value = oldent->d_name.name;
 779         req->in.args[2].size = newent->d_name.len + 1;
 780         req->in.args[2].value = newent->d_name.name;
 781         fuse_request_send(fc, req);
 782         err = req->out.h.error;
 783         fuse_put_request(fc, req);
 784         if (!err) {
 785                 /* ctime changes */
 786                 fuse_invalidate_attr(oldent->d_inode);
 787                 fuse_update_ctime(oldent->d_inode);
 788
 789                 if (flags & RENAME_EXCHANGE) {
 790                         fuse_invalidate_attr(newent->d_inode);
 791                         fuse_update_ctime(newent->d_inode);
 792                 }
 793
 794                 fuse_invalidate_attr(olddir);
 795                 if (olddir != newdir)
 796                         fuse_invalidate_attr(newdir);
 797
 798                 /* newent will end up negative */
 799                 if (!(flags & RENAME_EXCHANGE) && newent->d_inode) {
 800                         fuse_invalidate_attr(newent->d_inode);
 801                         fuse_invalidate_entry_cache(newent);
 802                         fuse_update_ctime(newent->d_inode);
 803                 }
 804         } else if (err == -EINTR) {
 805                 /* If request was interrupted, DEITY only knows if the
 806                    rename actually took place.  If the invalidation
 807                    fails (e.g. some process has CWD under the renamed
 808                    directory), then there can be inconsistency between
 809                    the dcache and the real filesystem.  Tough luck. */
 810                 fuse_invalidate_entry(oldent);
 811                 if (newent->d_inode)
 812                         fuse_invalidate_entry(newent);
 813         }
 814
 815         return err;
 816 }
 817
 818 static int fuse_rename(struct inode *olddir, struct dentry *oldent,
 819                        struct inode *newdir, struct dentry *newent)
 820 {
 821         return fuse_rename_common(olddir, oldent, newdir, newent, 0,
 822                                   FUSE_RENAME, sizeof(struct fuse_rename_in));
 823 }
 824
 825 static int fuse_rename2(struct inode *olddir, struct dentry *oldent,
 826                         struct inode *newdir, struct dentry *newent,
 827                         unsigned int flags)
 828 {
 829         struct fuse_conn *fc = get_fuse_conn(olddir);
 830         int err;
 831
 832         if (flags & ~(RENAME_NOREPLACE | RENAME_EXCHANGE))
 833                 return -EINVAL;
 834
 835         if (fc->no_rename2 || fc->minor < 23)
 836                 return -EINVAL;
 837
 838         err = fuse_rename_common(olddir, oldent, newdir, newent, flags,
 839                                  FUSE_RENAME2, sizeof(struct fuse_rename2_in));
 840         if (err == -ENOSYS) {
 841                 fc->no_rename2 = 1;
 842                 err = -EINVAL;
 843         }
 844         return err;
 845
 846 }
 847
 848 static int fuse_link(struct dentry *entry, struct inode *newdir,
 849                      struct dentry *newent)
 850 {
 851         int err;
 852         struct fuse_link_in inarg;
 853         struct inode *inode = entry->d_inode;
 854         struct fuse_conn *fc = get_fuse_conn(inode);
 855         struct fuse_req *req = fuse_get_req_nopages(fc);
 856         if (IS_ERR(req))
 857                 return PTR_ERR(req);
 858
 859         memset(&inarg, 0, sizeof(inarg));
 860         inarg.oldnodeid = get_node_id(inode);
 861         req->in.h.opcode = FUSE_LINK;
 862         req->in.numargs = 2;
 863         req->in.args[0].size = sizeof(inarg);
 864         req->in.args[0].value = &inarg;
 865         req->in.args[1].size = newent->d_name.len + 1;
 866         req->in.args[1].value = newent->d_name.name;
 867         err = create_new_entry(fc, req, newdir, newent, inode->i_mode);
 868         /* Contrary to "normal" filesystems it can happen that link
 869            makes two "logical" inodes point to the same "physical"
 870            inode.  We invalidate the attributes of the old one, so it
 871            will reflect changes in the backing inode (link count,
 872            etc.)
 873         */
 874         if (!err) {
 875                 struct fuse_inode *fi = get_fuse_inode(inode);
 876
 877                 spin_lock(&fc->lock);
 878                 fi->attr_version = ++fc->attr_version;
 879                 inc_nlink(inode);
 880                 spin_unlock(&fc->lock);
 881                 fuse_invalidate_attr(inode);
 882                 fuse_update_ctime(inode);
 883         } else if (err == -EINTR) {
 884                 fuse_invalidate_attr(inode);
 885         }
 886         return err;
 887 }
 888
 889 static void fuse_fillattr(struct inode *inode, struct fuse_attr *attr,
 890                           struct kstat *stat)
 891 {
 892         unsigned int blkbits;
 893         struct fuse_conn *fc = get_fuse_conn(inode);
 894
 895         /* see the comment in fuse_change_attributes() */
 896         if (fc->writeback_cache && S_ISREG(inode->i_mode)) {
 897                 attr->size = i_size_read(inode);
 898                 attr->mtime = inode->i_mtime.tv_sec;
 899                 attr->mtimensec = inode->i_mtime.tv_nsec;
 900                 attr->ctime = inode->i_ctime.tv_sec;
 901                 attr->ctimensec = inode->i_ctime.tv_nsec;
 902         }
 903
 904         stat->dev = inode->i_sb->s_dev;
 905         stat->ino = attr->ino;
 906         stat->mode = (inode->i_mode & S_IFMT) | (attr->mode & 07777);
 907         stat->nlink = attr->nlink;
 908         stat->uid = make_kuid(&init_user_ns, attr->uid);
 909         stat->gid = make_kgid(&init_user_ns, attr->gid);
 910         stat->rdev = inode->i_rdev;
 911         stat->atime.tv_sec = attr->atime;
 912         stat->atime.tv_nsec = attr->atimensec;
 913         stat->mtime.tv_sec = attr->mtime;
 914         stat->mtime.tv_nsec = attr->mtimensec;
 915         stat->ctime.tv_sec = attr->ctime;
 916         stat->ctime.tv_nsec = attr->ctimensec;
 917         stat->size = attr->size;
 918         stat->blocks = attr->blocks;
 919
 920         if (attr->blksize != 0)
 921                 blkbits = ilog2(attr->blksize);
 922         else
 923                 blkbits = inode->i_sb->s_blocksize_bits;
 924
 925         stat->blksize = 1 << blkbits;
 926 }
 927
 928 static int fuse_do_getattr(struct inode *inode, struct kstat *stat,
 929                            struct file *file)
 930 {
 931         int err;
 932         struct fuse_getattr_in inarg;
 933         struct fuse_attr_out outarg;
 934         struct fuse_conn *fc = get_fuse_conn(inode);
 935         struct fuse_req *req;
 936         u64 attr_version;
 937
 938         req = fuse_get_req_nopages(fc);
 939         if (IS_ERR(req))
 940                 return PTR_ERR(req);
 941
 942         attr_version = fuse_get_attr_version(fc);
 943
 944         memset(&inarg, 0, sizeof(inarg));
 945         memset(&outarg, 0, sizeof(outarg));
 946         /* Directories have separate file-handle space */
 947         if (file && S_ISREG(inode->i_mode)) {
 948                 struct fuse_file *ff = file->private_data;
 949
 950                 inarg.getattr_flags |= FUSE_GETATTR_FH;
 951                 inarg.fh = ff->fh;
 952         }
 953         req->in.h.opcode = FUSE_GETATTR;
 954         req->in.h.nodeid = get_node_id(inode);
 955         req->in.numargs = 1;
 956         req->in.args[0].size = sizeof(inarg);
 957         req->in.args[0].value = &inarg;
 958         req->out.numargs = 1;
 959         if (fc->minor < 9)
 960                 req->out.args[0].size = FUSE_COMPAT_ATTR_OUT_SIZE;
 961         else
 962                 req->out.args[0].size = sizeof(outarg);
 963         req->out.args[0].value = &outarg;
 964         fuse_request_send(fc, req);
 965         err = req->out.h.error;
 966         fuse_put_request(fc, req);
 967         if (!err) {
 968                 if ((inode->i_mode ^ outarg.attr.mode) & S_IFMT) {
 969                         make_bad_inode(inode);
 970                         err = -EIO;
 971                 } else {
 972                         fuse_change_attributes(inode, &outarg.attr,
 973                                                attr_timeout(&outarg),
 974                                                attr_version);
 975                         if (stat)
 976                                 fuse_fillattr(inode, &outarg.attr, stat);
 977                 }
 978         }
 979         return err;
 980 }
 981
 982 int fuse_update_attributes(struct inode *inode, struct kstat *stat,
 983                            struct file *file, bool *refreshed)
 984 {
 985         struct fuse_inode *fi = get_fuse_inode(inode);
 986         int err;
 987         bool r;
 988
 989         if (time_before64(fi->i_time, get_jiffies_64())) {
 990                 r = true;
 991                 err = fuse_do_getattr(inode, stat, file);
 992         } else {
 993                 r = false;
 994                 err = 0;
 995                 if (stat) {
 996                         generic_fillattr(inode, stat);
 997                         stat->mode = fi->orig_i_mode;
 998                         stat->ino = fi->orig_ino;
 999                 }
1000         }
1001
1002         if (refreshed != NULL)
1003                 *refreshed = r;
1004
1005         return err;
1006 }
1007
1008 int fuse_reverse_inval_entry(struct super_block *sb, u64 parent_nodeid,
1009                              u64 child_nodeid, struct qstr *name)
1010 {
1011         int err = -ENOTDIR;
1012         struct inode *parent;
1013         struct dentry *dir;
1014         struct dentry *entry;
1015
1016         parent = ilookup5(sb, parent_nodeid, fuse_inode_eq, &parent_nodeid);
1017         if (!parent)
1018                 return -ENOENT;
1019
1020         mutex_lock(&parent->i_mutex);
1021         if (!S_ISDIR(parent->i_mode))
1022                 goto unlock;
1023
1024         err = -ENOENT;
1025         dir = d_find_alias(parent);
1026         if (!dir)
1027                 goto unlock;
1028
1029         entry = d_lookup(dir, name);
1030         dput(dir);
1031         if (!entry)
1032                 goto unlock;
1033
1034         fuse_invalidate_attr(parent);
1035         fuse_invalidate_entry(entry);
1036
1037         if (child_nodeid != 0 && entry->d_inode) {
1038                 mutex_lock(&entry->d_inode->i_mutex);
1039                 if (get_node_id(entry->d_inode) != child_nodeid) {
1040                         err = -ENOENT;
1041                         goto badentry;
1042                 }
1043                 if (d_mountpoint(entry)) {
1044                         err = -EBUSY;
1045                         goto badentry;
1046                 }
1047                 if (S_ISDIR(entry->d_inode->i_mode)) {
1048                         shrink_dcache_parent(entry);
1049                         if (!simple_empty(entry)) {
1050                                 err = -ENOTEMPTY;
1051                                 goto badentry;
1052                         }
1053                         entry->d_inode->i_flags |= S_DEAD;
1054                 }
1055                 dont_mount(entry);
1056                 clear_nlink(entry->d_inode);
1057                 err = 0;
1058  badentry:
1059                 mutex_unlock(&entry->d_inode->i_mutex);
1060                 if (!err)
1061                         d_delete(entry);
1062         } else {
1063                 err = 0;
1064         }
1065         dput(entry);
1066
1067  unlock:
1068         mutex_unlock(&parent->i_mutex);
1069         iput(parent);
1070         return err;
1071 }
1072
1073 /*
1074  * Calling into a user-controlled filesystem gives the filesystem
1075  * daemon ptrace-like capabilities over the current process.  This
1076  * means, that the filesystem daemon is able to record the exact
1077  * filesystem operations performed, and can also control the behavior
1078  * of the requester process in otherwise impossible ways.  For example
1079  * it can delay the operation for arbitrary length of time allowing
1080  * DoS against the requester.
1081  *
1082  * For this reason only those processes can call into the filesystem,
1083  * for which the owner of the mount has ptrace privilege.  This
1084  * excludes processes started by other users, suid or sgid processes.
1085  */
1086 int fuse_allow_current_process(struct fuse_conn *fc)
1087 {
1088         const struct cred *cred;
1089
1090         if (fc->flags & FUSE_ALLOW_OTHER)
1091                 return 1;
1092
1093         cred = current_cred();
1094         if (uid_eq(cred->euid, fc->user_id) &&
1095             uid_eq(cred->suid, fc->user_id) &&
1096             uid_eq(cred->uid,  fc->user_id) &&
1097             gid_eq(cred->egid, fc->group_id) &&
1098             gid_eq(cred->sgid, fc->group_id) &&
1099             gid_eq(cred->gid,  fc->group_id))
1100                 return 1;
1101
1102         return 0;
1103 }
1104
1105 static int fuse_access(struct inode *inode, int mask)
1106 {
1107         struct fuse_conn *fc = get_fuse_conn(inode);
1108         struct fuse_req *req;
1109         struct fuse_access_in inarg;
1110         int err;
1111
1112         BUG_ON(mask & MAY_NOT_BLOCK);
1113
1114         if (fc->no_access)
1115                 return 0;
1116
1117         req = fuse_get_req_nopages(fc);
1118         if (IS_ERR(req))
1119                 return PTR_ERR(req);
1120
1121         memset(&inarg, 0, sizeof(inarg));
1122         inarg.mask = mask & (MAY_READ | MAY_WRITE | MAY_EXEC);
1123         req->in.h.opcode = FUSE_ACCESS;
1124         req->in.h.nodeid = get_node_id(inode);
1125         req->in.numargs = 1;
1126         req->in.args[0].size = sizeof(inarg);
1127         req->in.args[0].value = &inarg;
1128         fuse_request_send(fc, req);
1129         err = req->out.h.error;
1130         fuse_put_request(fc, req);
1131         if (err == -ENOSYS) {
1132                 fc->no_access = 1;
1133                 err = 0;
1134         }
1135         return err;
1136 }
1137
1138 static int fuse_perm_getattr(struct inode *inode, int mask)
1139 {
1140         if (mask & MAY_NOT_BLOCK)
1141                 return -ECHILD;
1142
1143         return fuse_do_getattr(inode, NULL, NULL);
1144 }
1145
1146 /*
1147  * Check permission.  The two basic access models of FUSE are:
1148  *
1149  * 1) Local access checking ('default_permissions' mount option) based
1150  * on file mode.  This is the plain old disk filesystem permission
1151  * modell.
1152  *
1153  * 2) "Remote" access checking, where server is responsible for
1154  * checking permission in each inode operation.  An exception to this
1155  * is if ->permission() was invoked from sys_access() in which case an
1156  * access request is sent.  Execute permission is still checked
1157  * locally based on file mode.
1158  */
1159 static int fuse_permission(struct inode *inode, int mask)
1160 {
1161         struct fuse_conn *fc = get_fuse_conn(inode);
1162         bool refreshed = false;
1163         int err = 0;
1164
1165         if (!fuse_allow_current_process(fc))
1166                 return -EACCES;
1167
1168         /*
1169          * If attributes are needed, refresh them before proceeding
1170          */
1171         if ((fc->flags & FUSE_DEFAULT_PERMISSIONS) ||
1172             ((mask & MAY_EXEC) && S_ISREG(inode->i_mode))) {
1173                 struct fuse_inode *fi = get_fuse_inode(inode);
1174
1175                 if (time_before64(fi->i_time, get_jiffies_64())) {
1176                         refreshed = true;
1177
1178                         err = fuse_perm_getattr(inode, mask);
1179                         if (err)
1180                                 return err;
1181                 }
1182         }
1183
1184         if (fc->flags & FUSE_DEFAULT_PERMISSIONS) {
1185                 err = generic_permission(inode, mask);
1186
1187                 /* If permission is denied, try to refresh file
1188                    attributes.  This is also needed, because the root
1189                    node will at first have no permissions */
1190                 if (err == -EACCES && !refreshed) {
1191                         err = fuse_perm_getattr(inode, mask);
1192                         if (!err)
1193                                 err = generic_permission(inode, mask);
1194                 }
1195
1196                 /* Note: the opposite of the above test does not
1197                    exist.  So if permissions are revoked this won't be
1198                    noticed immediately, only after the attribute
1199                    timeout has expired */
1200         } else if (mask & (MAY_ACCESS | MAY_CHDIR)) {
1201                 err = fuse_access(inode, mask);
1202         } else if ((mask & MAY_EXEC) && S_ISREG(inode->i_mode)) {
1203                 if (!(inode->i_mode & S_IXUGO)) {
1204                         if (refreshed)
1205                                 return -EACCES;
1206
1207                         err = fuse_perm_getattr(inode, mask);
1208                         if (!err && !(inode->i_mode & S_IXUGO))
1209                                 return -EACCES;
1210                 }
1211         }
1212         return err;
1213 }
1214
1215 static int parse_dirfile(char *buf, size_t nbytes, struct file *file,
1216                          struct dir_context *ctx)
1217 {
1218         while (nbytes >= FUSE_NAME_OFFSET) {
1219                 struct fuse_dirent *dirent = (struct fuse_dirent *) buf;
1220                 size_t reclen = FUSE_DIRENT_SIZE(dirent);
1221                 if (!dirent->namelen || dirent->namelen > FUSE_NAME_MAX)
1222                         return -EIO;
1223                 if (reclen > nbytes)
1224                         break;
1225                 if (memchr(dirent->name, '/', dirent->namelen) != NULL)
1226                         return -EIO;
1227
1228                 if (!dir_emit(ctx, dirent->name, dirent->namelen,
1229                                dirent->ino, dirent->type))
1230                         break;
1231
1232                 buf += reclen;
1233                 nbytes -= reclen;
1234                 ctx->pos = dirent->off;
1235         }
1236
1237         return 0;
1238 }
1239
1240 static int fuse_direntplus_link(struct file *file,
1241                                 struct fuse_direntplus *direntplus,
1242                                 u64 attr_version)
1243 {
1244         int err;
1245         struct fuse_entry_out *o = &direntplus->entry_out;
1246         struct fuse_dirent *dirent = &direntplus->dirent;
1247         struct dentry *parent = file->f_path.dentry;
1248         struct qstr name = QSTR_INIT(dirent->name, dirent->namelen);
1249         struct dentry *dentry;
1250         struct dentry *alias;
1251         struct inode *dir = parent->d_inode;
1252         struct fuse_conn *fc;
1253         struct inode *inode;
1254
1255         if (!o->nodeid) {
1256                 /*
1257                  * Unlike in the case of fuse_lookup, zero nodeid does not mean
1258                  * ENOENT. Instead, it only means the userspace filesystem did
1259                  * not want to return attributes/handle for this entry.
1260                  *
1261                  * So do nothing.
1262                  */
1263                 return 0;
1264         }
1265
1266         if (name.name[0] == '.') {
1267                 /*
1268                  * We could potentially refresh the attributes of the directory
1269                  * and its parent?
1270                  */
1271                 if (name.len == 1)
1272                         return 0;
1273                 if (name.name[1] == '.' && name.len == 2)
1274                         return 0;
1275         }
1276
1277         if (invalid_nodeid(o->nodeid))
1278                 return -EIO;
1279         if (!fuse_valid_type(o->attr.mode))
1280                 return -EIO;
1281
1282         fc = get_fuse_conn(dir);
1283
1284         name.hash = full_name_hash(name.name, name.len);
1285         dentry = d_lookup(parent, &name);
1286         if (dentry) {
1287                 inode = dentry->d_inode;
1288                 if (!inode) {
1289                         d_drop(dentry);
1290                 } else if (get_node_id(inode) != o->nodeid ||
1291                            ((o->attr.mode ^ inode->i_mode) & S_IFMT)) {
1292                         err = d_invalidate(dentry);
1293                         if (err)
1294                                 goto out;
1295                 } else if (is_bad_inode(inode)) {
1296                         err = -EIO;
1297                         goto out;
1298                 } else {
1299                         struct fuse_inode *fi;
1300                         fi = get_fuse_inode(inode);
1301                         spin_lock(&fc->lock);
1302                         fi->nlookup++;
1303                         spin_unlock(&fc->lock);
1304
1305                         fuse_change_attributes(inode, &o->attr,
1306                                                entry_attr_timeout(o),
1307                                                attr_version);
1308
1309                         /*
1310                          * The other branch to 'found' comes via fuse_iget()
1311                          * which bumps nlookup inside
1312                          */
1313                         goto found;
1314                 }
1315                 dput(dentry);
1316         }
1317
1318         dentry = d_alloc(parent, &name);
1319         err = -ENOMEM;
1320         if (!dentry)
1321                 goto out;
1322
1323         inode = fuse_iget(dir->i_sb, o->nodeid, o->generation,
1324                           &o->attr, entry_attr_timeout(o), attr_version);
1325         if (!inode)
1326                 goto out;
1327
1328         alias = d_materialise_unique(dentry, inode);
1329         err = PTR_ERR(alias);
1330         if (IS_ERR(alias))
1331                 goto out;
1332
1333         if (alias) {
1334                 dput(dentry);
1335                 dentry = alias;
1336         }
1337
1338 found:
1339         if (fc->readdirplus_auto)
1340                 set_bit(FUSE_I_INIT_RDPLUS, &get_fuse_inode(inode)->state);
1341         fuse_change_entry_timeout(dentry, o);
1342
1343         err = 0;
1344 out:
1345         dput(dentry);
1346         return err;
1347 }
1348
1349 static int parse_dirplusfile(char *buf, size_t nbytes, struct file *file,
1350                              struct dir_context *ctx, u64 attr_version)
1351 {
1352         struct fuse_direntplus *direntplus;
1353         struct fuse_dirent *dirent;
1354         size_t reclen;
1355         int over = 0;
1356         int ret;
1357
1358         while (nbytes >= FUSE_NAME_OFFSET_DIRENTPLUS) {
1359                 direntplus = (struct fuse_direntplus *) buf;
1360                 dirent = &direntplus->dirent;
1361                 reclen = FUSE_DIRENTPLUS_SIZE(direntplus);
1362
1363                 if (!dirent->namelen || dirent->namelen > FUSE_NAME_MAX)
1364                         return -EIO;
1365                 if (reclen > nbytes)
1366                         break;
1367                 if (memchr(dirent->name, '/', dirent->namelen) != NULL)
1368                         return -EIO;
1369
1370                 if (!over) {
1371                         /* We fill entries into dstbuf only as much as
1372                            it can hold. But we still continue iterating
1373                            over remaining entries to link them. If not,
1374                            we need to send a FORGET for each of those
1375                            which we did not link.
1376                         */
1377                         over = !dir_emit(ctx, dirent->name, dirent->namelen,
1378                                        dirent->ino, dirent->type);
1379                         ctx->pos = dirent->off;
1380                 }
1381
1382                 buf += reclen;
1383                 nbytes -= reclen;
1384
1385                 ret = fuse_direntplus_link(file, direntplus, attr_version);
1386                 if (ret)
1387                         fuse_force_forget(file, direntplus->entry_out.nodeid);
1388         }
1389
1390         return 0;
1391 }
1392
1393 static int fuse_readdir(struct file *file, struct dir_context *ctx)
1394 {
1395         int plus, err;
1396         size_t nbytes;
1397         struct page *page;
1398         struct inode *inode = file_inode(file);
1399         struct fuse_conn *fc = get_fuse_conn(inode);
1400         struct fuse_req *req;
1401         u64 attr_version = 0;
1402
1403         if (is_bad_inode(inode))
1404                 return -EIO;
1405
1406         req = fuse_get_req(fc, 1);
1407         if (IS_ERR(req))
1408                 return PTR_ERR(req);
1409
1410         page = alloc_page(GFP_KERNEL);
1411         if (!page) {
1412                 fuse_put_request(fc, req);
1413                 return -ENOMEM;
1414         }
1415
1416         plus = fuse_use_readdirplus(inode, ctx);
1417         req->out.argpages = 1;
1418         req->num_pages = 1;
1419         req->pages[0] = page;
1420         req->page_descs[0].length = PAGE_SIZE;
1421         if (plus) {
1422                 attr_version = fuse_get_attr_version(fc);
1423                 fuse_read_fill(req, file, ctx->pos, PAGE_SIZE,
1424                                FUSE_READDIRPLUS);
1425         } else {
1426                 fuse_read_fill(req, file, ctx->pos, PAGE_SIZE,
1427                                FUSE_READDIR);
1428         }
1429         fuse_request_send(fc, req);
1430         nbytes = req->out.args[0].size;
1431         err = req->out.h.error;
1432         fuse_put_request(fc, req);
1433         if (!err) {
1434                 if (plus) {
1435                         err = parse_dirplusfile(page_address(page), nbytes,
1436                                                 file, ctx,
1437                                                 attr_version);
1438                 } else {
1439                         err = parse_dirfile(page_address(page), nbytes, file,
1440                                             ctx);
1441                 }
1442         }
1443
1444         __free_page(page);
1445         fuse_invalidate_atime(inode);
1446         return err;
1447 }
1448
1449 static char *read_link(struct dentry *dentry)
1450 {
1451         struct inode *inode = dentry->d_inode;
1452         struct fuse_conn *fc = get_fuse_conn(inode);
1453         struct fuse_req *req = fuse_get_req_nopages(fc);
1454         char *link;
1455
1456         if (IS_ERR(req))
1457                 return ERR_CAST(req);
1458
1459         link = (char *) __get_free_page(GFP_KERNEL);
1460         if (!link) {
1461                 link = ERR_PTR(-ENOMEM);
1462                 goto out;
1463         }
1464         req->in.h.opcode = FUSE_READLINK;
1465         req->in.h.nodeid = get_node_id(inode);
1466         req->out.argvar = 1;
1467         req->out.numargs = 1;
1468         req->out.args[0].size = PAGE_SIZE - 1;
1469         req->out.args[0].value = link;
1470         fuse_request_send(fc, req);
1471         if (req->out.h.error) {
1472                 free_page((unsigned long) link);
1473                 link = ERR_PTR(req->out.h.error);
1474         } else
1475                 link[req->out.args[0].size] = '\0';
1476  out:
1477         fuse_put_request(fc, req);
1478         fuse_invalidate_atime(inode);
1479         return link;
1480 }
1481
1482 static void free_link(char *link)
1483 {
1484         if (!IS_ERR(link))
1485                 free_page((unsigned long) link);
1486 }
1487
1488 static void *fuse_follow_link(struct dentry *dentry, struct nameidata *nd)
1489 {
1490         nd_set_link(nd, read_link(dentry));
1491         return NULL;
1492 }
1493
1494 static void fuse_put_link(struct dentry *dentry, struct nameidata *nd, void *c)
1495 {
1496         free_link(nd_get_link(nd));
1497 }
1498
1499 static int fuse_dir_open(struct inode *inode, struct file *file)
1500 {
1501         return fuse_open_common(inode, file, true);
1502 }
1503
1504 static int fuse_dir_release(struct inode *inode, struct file *file)
1505 {
1506         fuse_release_common(file, FUSE_RELEASEDIR);
1507
1508         return 0;
1509 }
1510
1511 static int fuse_dir_fsync(struct file *file, loff_t start, loff_t end,
1512                           int datasync)
1513 {
1514         return fuse_fsync_common(file, start, end, datasync, 1);
1515 }
1516
1517 static long fuse_dir_ioctl(struct file *file, unsigned int cmd,
1518                             unsigned long arg)
1519 {
1520         struct fuse_conn *fc = get_fuse_conn(file->f_mapping->host);
1521
1522         /* FUSE_IOCTL_DIR only supported for API version >= 7.18 */
1523         if (fc->minor < 18)
1524                 return -ENOTTY;
1525
1526         return fuse_ioctl_common(file, cmd, arg, FUSE_IOCTL_DIR);
1527 }
1528
1529 static long fuse_dir_compat_ioctl(struct file *file, unsigned int cmd,
1530                                    unsigned long arg)
1531 {
1532         struct fuse_conn *fc = get_fuse_conn(file->f_mapping->host);
1533
1534         if (fc->minor < 18)
1535                 return -ENOTTY;
1536
1537         return fuse_ioctl_common(file, cmd, arg,
1538                                  FUSE_IOCTL_COMPAT | FUSE_IOCTL_DIR);
1539 }
1540
1541 static bool update_mtime(unsigned ivalid, bool trust_local_mtime)
1542 {
1543         /* Always update if mtime is explicitly set  */
1544         if (ivalid & ATTR_MTIME_SET)
1545                 return true;
1546
1547         /* Or if kernel i_mtime is the official one */
1548         if (trust_local_mtime)
1549                 return true;
1550
1551         /* If it's an open(O_TRUNC) or an ftruncate(), don't update */
1552         if ((ivalid & ATTR_SIZE) && (ivalid & (ATTR_OPEN | ATTR_FILE)))
1553                 return false;
1554
1555         /* In all other cases update */
1556         return true;
1557 }
1558
1559 static void iattr_to_fattr(struct iattr *iattr, struct fuse_setattr_in *arg,
1560                            bool trust_local_cmtime)
1561 {
1562         unsigned ivalid = iattr->ia_valid;
1563
1564         if (ivalid & ATTR_MODE)
1565                 arg->valid |= FATTR_MODE,   arg->mode = iattr->ia_mode;
1566         if (ivalid & ATTR_UID)
1567                 arg->valid |= FATTR_UID,    arg->uid = from_kuid(&init_user_ns, iattr->ia_uid);
1568         if (ivalid & ATTR_GID)
1569                 arg->valid |= FATTR_GID,    arg->gid = from_kgid(&init_user_ns, iattr->ia_gid);
1570         if (ivalid & ATTR_SIZE)
1571                 arg->valid |= FATTR_SIZE,   arg->size = iattr->ia_size;
1572         if (ivalid & ATTR_ATIME) {
1573                 arg->valid |= FATTR_ATIME;
1574                 arg->atime = iattr->ia_atime.tv_sec;
1575                 arg->atimensec = iattr->ia_atime.tv_nsec;
1576                 if (!(ivalid & ATTR_ATIME_SET))
1577                         arg->valid |= FATTR_ATIME_NOW;
1578         }
1579         if ((ivalid & ATTR_MTIME) && update_mtime(ivalid, trust_local_cmtime)) {
1580                 arg->valid |= FATTR_MTIME;
1581                 arg->mtime = iattr->ia_mtime.tv_sec;
1582                 arg->mtimensec = iattr->ia_mtime.tv_nsec;
1583                 if (!(ivalid & ATTR_MTIME_SET) && !trust_local_cmtime)
1584                         arg->valid |= FATTR_MTIME_NOW;
1585         }
1586         if ((ivalid & ATTR_CTIME) && trust_local_cmtime) {
1587                 arg->valid |= FATTR_CTIME;
1588                 arg->ctime = iattr->ia_ctime.tv_sec;
1589                 arg->ctimensec = iattr->ia_ctime.tv_nsec;
1590         }
1591 }
1592
1593 /*
1594  * Prevent concurrent writepages on inode
1595  *
1596  * This is done by adding a negative bias to the inode write counter
1597  * and waiting for all pending writes to finish.
1598  */
1599 void fuse_set_nowrite(struct inode *inode)
1600 {
1601         struct fuse_conn *fc = get_fuse_conn(inode);
1602         struct fuse_inode *fi = get_fuse_inode(inode);
1603
1604         BUG_ON(!mutex_is_locked(&inode->i_mutex));
1605
1606         spin_lock(&fc->lock);
1607         BUG_ON(fi->writectr < 0);
1608         fi->writectr += FUSE_NOWRITE;
1609         spin_unlock(&fc->lock);
1610         wait_event(fi->page_waitq, fi->writectr == FUSE_NOWRITE);
1611 }
1612
1613 /*
1614  * Allow writepages on inode
1615  *
1616  * Remove the bias from the writecounter and send any queued
1617  * writepages.
1618  */
1619 static void __fuse_release_nowrite(struct inode *inode)
1620 {
1621         struct fuse_inode *fi = get_fuse_inode(inode);
1622
1623         BUG_ON(fi->writectr != FUSE_NOWRITE);
1624         fi->writectr = 0;
1625         fuse_flush_writepages(inode);
1626 }
1627
1628 void fuse_release_nowrite(struct inode *inode)
1629 {
1630         struct fuse_conn *fc = get_fuse_conn(inode);
1631
1632         spin_lock(&fc->lock);
1633         __fuse_release_nowrite(inode);
1634         spin_unlock(&fc->lock);
1635 }
1636
1637 static void fuse_setattr_fill(struct fuse_conn *fc, struct fuse_req *req,
1638                               struct inode *inode,
1639                               struct fuse_setattr_in *inarg_p,
1640                               struct fuse_attr_out *outarg_p)
1641 {
1642         req->in.h.opcode = FUSE_SETATTR;
1643         req->in.h.nodeid = get_node_id(inode);
1644         req->in.numargs = 1;
1645         req->in.args[0].size = sizeof(*inarg_p);
1646         req->in.args[0].value = inarg_p;
1647         req->out.numargs = 1;
1648         if (fc->minor < 9)
1649                 req->out.args[0].size = FUSE_COMPAT_ATTR_OUT_SIZE;
1650         else
1651                 req->out.args[0].size = sizeof(*outarg_p);
1652         req->out.args[0].value = outarg_p;
1653 }
1654
1655 /*
1656  * Flush inode->i_mtime to the server
1657  */
1658 int fuse_flush_times(struct inode *inode, struct fuse_file *ff)
1659 {
1660         struct fuse_conn *fc = get_fuse_conn(inode);
1661         struct fuse_req *req;
1662         struct fuse_setattr_in inarg;
1663         struct fuse_attr_out outarg;
1664         int err;
1665
1666         req = fuse_get_req_nopages(fc);
1667         if (IS_ERR(req))
1668                 return PTR_ERR(req);
1669
1670         memset(&inarg, 0, sizeof(inarg));
1671         memset(&outarg, 0, sizeof(outarg));
1672
1673         inarg.valid = FATTR_MTIME;
1674         inarg.mtime = inode->i_mtime.tv_sec;
1675         inarg.mtimensec = inode->i_mtime.tv_nsec;
1676         if (fc->minor >= 23) {
1677                 inarg.valid |= FATTR_CTIME;
1678                 inarg.ctime = inode->i_ctime.tv_sec;
1679                 inarg.ctimensec = inode->i_ctime.tv_nsec;
1680         }
1681         if (ff) {
1682                 inarg.valid |= FATTR_FH;
1683                 inarg.fh = ff->fh;
1684         }
1685         fuse_setattr_fill(fc, req, inode, &inarg, &outarg);
1686         fuse_request_send(fc, req);
1687         err = req->out.h.error;
1688         fuse_put_request(fc, req);
1689
1690         return err;
1691 }
1692
1693 /*
1694  * Set attributes, and at the same time refresh them.
1695  *
1696  * Truncation is slightly complicated, because the 'truncate' request
1697  * may fail, in which case we don't want to touch the mapping.
1698  * vmtruncate() doesn't allow for this case, so do the rlimit checking
1699  * and the actual truncation by hand.
1700  */
1701 int fuse_do_setattr(struct inode *inode, struct iattr *attr,
1702                     struct file *file)
1703 {
1704         struct fuse_conn *fc = get_fuse_conn(inode);
1705         struct fuse_inode *fi = get_fuse_inode(inode);
1706         struct fuse_req *req;
1707         struct fuse_setattr_in inarg;
1708         struct fuse_attr_out outarg;
1709         bool is_truncate = false;
1710         bool is_wb = fc->writeback_cache;
1711         loff_t oldsize;
1712         int err;
1713         bool trust_local_cmtime = is_wb && S_ISREG(inode->i_mode);
1714
1715         if (!(fc->flags & FUSE_DEFAULT_PERMISSIONS))
1716                 attr->ia_valid |= ATTR_FORCE;
1717
1718         err = inode_change_ok(inode, attr);
1719         if (err)
1720                 return err;
1721
1722         if (attr->ia_valid & ATTR_OPEN) {
1723                 if (fc->atomic_o_trunc)
1724                         return 0;
1725                 file = NULL;
1726         }
1727
1728         if (attr->ia_valid & ATTR_SIZE)
1729                 is_truncate = true;
1730
1731         req = fuse_get_req_nopages(fc);
1732         if (IS_ERR(req))
1733                 return PTR_ERR(req);
1734
1735         if (is_truncate) {
1736                 fuse_set_nowrite(inode);
1737                 set_bit(FUSE_I_SIZE_UNSTABLE, &fi->state);
1738                 if (trust_local_cmtime && attr->ia_size != inode->i_size)
1739                         attr->ia_valid |= ATTR_MTIME | ATTR_CTIME;
1740         }
1741
1742         memset(&inarg, 0, sizeof(inarg));
1743         memset(&outarg, 0, sizeof(outarg));
1744         iattr_to_fattr(attr, &inarg, trust_local_cmtime);
1745         if (file) {
1746                 struct fuse_file *ff = file->private_data;
1747                 inarg.valid |= FATTR_FH;
1748                 inarg.fh = ff->fh;
1749         }
1750         if (attr->ia_valid & ATTR_SIZE) {
1751                 /* For mandatory locking in truncate */
1752                 inarg.valid |= FATTR_LOCKOWNER;
1753                 inarg.lock_owner = fuse_lock_owner_id(fc, current->files);
1754         }
1755         fuse_setattr_fill(fc, req, inode, &inarg, &outarg);
1756         fuse_request_send(fc, req);
1757         err = req->out.h.error;
1758         fuse_put_request(fc, req);
1759         if (err) {
1760                 if (err == -EINTR)
1761                         fuse_invalidate_attr(inode);
1762                 goto error;
1763         }
1764
1765         if ((inode->i_mode ^ outarg.attr.mode) & S_IFMT) {
1766                 make_bad_inode(inode);
1767                 err = -EIO;
1768                 goto error;
1769         }
1770
1771         spin_lock(&fc->lock);
1772         /* the kernel maintains i_mtime locally */
1773         if (trust_local_cmtime) {
1774                 if (attr->ia_valid & ATTR_MTIME)
1775                         inode->i_mtime = attr->ia_mtime;
1776                 if (attr->ia_valid & ATTR_CTIME)
1777                         inode->i_ctime = attr->ia_ctime;
1778                 /* FIXME: clear I_DIRTY_SYNC? */
1779         }
1780
1781         fuse_change_attributes_common(inode, &outarg.attr,
1782                                       attr_timeout(&outarg));
1783         oldsize = inode->i_size;
1784         /* see the comment in fuse_change_attributes() */
1785         if (!is_wb || is_truncate || !S_ISREG(inode->i_mode))
1786                 i_size_write(inode, outarg.attr.size);
1787
1788         if (is_truncate) {
1789                 /* NOTE: this may release/reacquire fc->lock */
1790                 __fuse_release_nowrite(inode);
1791         }
1792         spin_unlock(&fc->lock);
1793
1794         /*
1795          * Only call invalidate_inode_pages2() after removing
1796          * FUSE_NOWRITE, otherwise fuse_launder_page() would deadlock.
1797          */
1798         if ((is_truncate || !is_wb) &&
1799             S_ISREG(inode->i_mode) && oldsize != outarg.attr.size) {
1800                 truncate_pagecache(inode, outarg.attr.size);
1801                 invalidate_inode_pages2(inode->i_mapping);
1802         }
1803
1804         clear_bit(FUSE_I_SIZE_UNSTABLE, &fi->state);
1805         return 0;
1806
1807 error:
1808         if (is_truncate)
1809                 fuse_release_nowrite(inode);
1810
1811         clear_bit(FUSE_I_SIZE_UNSTABLE, &fi->state);
1812         return err;
1813 }
1814
1815 static int fuse_setattr(struct dentry *entry, struct iattr *attr)
1816 {
1817         struct inode *inode = entry->d_inode;
1818
1819         if (!fuse_allow_current_process(get_fuse_conn(inode)))
1820                 return -EACCES;
1821
1822         if (attr->ia_valid & ATTR_FILE)
1823                 return fuse_do_setattr(inode, attr, attr->ia_file);
1824         else
1825                 return fuse_do_setattr(inode, attr, NULL);
1826 }
1827
1828 static int fuse_getattr(struct vfsmount *mnt, struct dentry *entry,
1829                         struct kstat *stat)
1830 {
1831         struct inode *inode = entry->d_inode;
1832         struct fuse_conn *fc = get_fuse_conn(inode);
1833
1834         if (!fuse_allow_current_process(fc))
1835                 return -EACCES;
1836
1837         return fuse_update_attributes(inode, stat, NULL, NULL);
1838 }
1839
1840 static int fuse_setxattr(struct dentry *entry, const char *name,
1841                          const void *value, size_t size, int flags)
1842 {
1843         struct inode *inode = entry->d_inode;
1844         struct fuse_conn *fc = get_fuse_conn(inode);
1845         struct fuse_req *req;
1846         struct fuse_setxattr_in inarg;
1847         int err;
1848
1849         if (fc->no_setxattr)
1850                 return -EOPNOTSUPP;
1851
1852         req = fuse_get_req_nopages(fc);
1853         if (IS_ERR(req))
1854                 return PTR_ERR(req);
1855
1856         memset(&inarg, 0, sizeof(inarg));
1857         inarg.size = size;
1858         inarg.flags = flags;
1859         req->in.h.opcode = FUSE_SETXATTR;
1860         req->in.h.nodeid = get_node_id(inode);
1861         req->in.numargs = 3;
1862         req->in.args[0].size = sizeof(inarg);
1863         req->in.args[0].value = &inarg;
1864         req->in.args[1].size = strlen(name) + 1;
1865         req->in.args[1].value = name;
1866         req->in.args[2].size = size;
1867         req->in.args[2].value = value;
1868         fuse_request_send(fc, req);
1869         err = req->out.h.error;
1870         fuse_put_request(fc, req);
1871         if (err == -ENOSYS) {
1872                 fc->no_setxattr = 1;
1873                 err = -EOPNOTSUPP;
1874         }
1875         if (!err) {
1876                 fuse_invalidate_attr(inode);
1877                 fuse_update_ctime(inode);
1878         }
1879         return err;
1880 }
1881
1882 static ssize_t fuse_getxattr(struct dentry *entry, const char *name,
1883                              void *value, size_t size)
1884 {
1885         struct inode *inode = entry->d_inode;
1886         struct fuse_conn *fc = get_fuse_conn(inode);
1887         struct fuse_req *req;
1888         struct fuse_getxattr_in inarg;
1889         struct fuse_getxattr_out outarg;
1890         ssize_t ret;
1891
1892         if (fc->no_getxattr)
1893                 return -EOPNOTSUPP;
1894
1895         req = fuse_get_req_nopages(fc);
1896         if (IS_ERR(req))
1897                 return PTR_ERR(req);
1898
1899         memset(&inarg, 0, sizeof(inarg));
1900         inarg.size = size;
1901         req->in.h.opcode = FUSE_GETXATTR;
1902         req->in.h.nodeid = get_node_id(inode);
1903         req->in.numargs = 2;
1904         req->in.args[0].size = sizeof(inarg);
1905         req->in.args[0].value = &inarg;
1906         req->in.args[1].size = strlen(name) + 1;
1907         req->in.args[1].value = name;
1908         /* This is really two different operations rolled into one */
1909         req->out.numargs = 1;
1910         if (size) {
1911                 req->out.argvar = 1;
1912                 req->out.args[0].size = size;
1913                 req->out.args[0].value = value;
1914         } else {
1915                 req->out.args[0].size = sizeof(outarg);
1916                 req->out.args[0].value = &outarg;
1917         }
1918         fuse_request_send(fc, req);
1919         ret = req->out.h.error;
1920         if (!ret)
1921                 ret = size ? req->out.args[0].size : outarg.size;
1922         else {
1923                 if (ret == -ENOSYS) {
1924                         fc->no_getxattr = 1;
1925                         ret = -EOPNOTSUPP;
1926                 }
1927         }
1928         fuse_put_request(fc, req);
1929         return ret;
1930 }
1931
1932 static ssize_t fuse_listxattr(struct dentry *entry, char *list, size_t size)
1933 {
1934         struct inode *inode = entry->d_inode;
1935         struct fuse_conn *fc = get_fuse_conn(inode);
1936         struct fuse_req *req;
1937         struct fuse_getxattr_in inarg;
1938         struct fuse_getxattr_out outarg;
1939         ssize_t ret;
1940
1941         if (!fuse_allow_current_process(fc))
1942                 return -EACCES;
1943
1944         if (fc->no_listxattr)
1945                 return -EOPNOTSUPP;
1946
1947         req = fuse_get_req_nopages(fc);
1948         if (IS_ERR(req))
1949                 return PTR_ERR(req);
1950
1951         memset(&inarg, 0, sizeof(inarg));
1952         inarg.size = size;
1953         req->in.h.opcode = FUSE_LISTXATTR;
1954         req->in.h.nodeid = get_node_id(inode);
1955         req->in.numargs = 1;
1956         req->in.args[0].size = sizeof(inarg);
1957         req->in.args[0].value = &inarg;
1958         /* This is really two different operations rolled into one */
1959         req->out.numargs = 1;
1960         if (size) {
1961                 req->out.argvar = 1;
1962                 req->out.args[0].size = size;
1963                 req->out.args[0].value = list;
1964         } else {
1965                 req->out.args[0].size = sizeof(outarg);
1966                 req->out.args[0].value = &outarg;
1967         }
1968         fuse_request_send(fc, req);
1969         ret = req->out.h.error;
1970         if (!ret)
1971                 ret = size ? req->out.args[0].size : outarg.size;
1972         else {
1973                 if (ret == -ENOSYS) {
1974                         fc->no_listxattr = 1;
1975                         ret = -EOPNOTSUPP;
1976                 }
1977         }
1978         fuse_put_request(fc, req);
1979         return ret;
1980 }
1981
1982 static int fuse_removexattr(struct dentry *entry, const char *name)
1983 {
1984         struct inode *inode = entry->d_inode;
1985         struct fuse_conn *fc = get_fuse_conn(inode);
1986         struct fuse_req *req;
1987         int err;
1988
1989         if (fc->no_removexattr)
1990                 return -EOPNOTSUPP;
1991
1992         req = fuse_get_req_nopages(fc);
1993         if (IS_ERR(req))
1994                 return PTR_ERR(req);
1995
1996         req->in.h.opcode = FUSE_REMOVEXATTR;
1997         req->in.h.nodeid = get_node_id(inode);
1998         req->in.numargs = 1;
1999         req->in.args[0].size = strlen(name) + 1;
2000         req->in.args[0].value = name;
2001         fuse_request_send(fc, req);
2002         err = req->out.h.error;
2003         fuse_put_request(fc, req);
2004         if (err == -ENOSYS) {
2005                 fc->no_removexattr = 1;
2006                 err = -EOPNOTSUPP;
2007         }
2008         if (!err) {
2009                 fuse_invalidate_attr(inode);
2010                 fuse_update_ctime(inode);
2011         }
2012         return err;
2013 }
2014
2015 static const struct inode_operations fuse_dir_inode_operations = {
2016         .lookup         = fuse_lookup,
2017         .mkdir          = fuse_mkdir,
2018         .symlink        = fuse_symlink,
2019         .unlink         = fuse_unlink,
2020         .rmdir          = fuse_rmdir,
2021         .rename         = fuse_rename,
2022         .rename2        = fuse_rename2,
2023         .link           = fuse_link,
2024         .setattr        = fuse_setattr,
2025         .create         = fuse_create,
2026         .atomic_open    = fuse_atomic_open,
2027         .mknod          = fuse_mknod,
2028         .permission     = fuse_permission,
2029         .getattr        = fuse_getattr,
2030         .setxattr       = fuse_setxattr,
2031         .getxattr       = fuse_getxattr,
2032         .listxattr      = fuse_listxattr,
2033         .removexattr    = fuse_removexattr,
2034 };
2035
2036 static const struct file_operations fuse_dir_operations = {
2037         .llseek         = generic_file_llseek,
2038         .read           = generic_read_dir,
2039         .iterate        = fuse_readdir,
2040         .open           = fuse_dir_open,
2041         .release        = fuse_dir_release,
2042         .fsync          = fuse_dir_fsync,
2043         .unlocked_ioctl = fuse_dir_ioctl,
2044         .compat_ioctl   = fuse_dir_compat_ioctl,
2045 };
2046
2047 static const struct inode_operations fuse_common_inode_operations = {
2048         .setattr        = fuse_setattr,
2049         .permission     = fuse_permission,
2050         .getattr        = fuse_getattr,
2051         .setxattr       = fuse_setxattr,
2052         .getxattr       = fuse_getxattr,
2053         .listxattr      = fuse_listxattr,
2054         .removexattr    = fuse_removexattr,
2055 };
2056
2057 static const struct inode_operations fuse_symlink_inode_operations = {
2058         .setattr        = fuse_setattr,
2059         .follow_link    = fuse_follow_link,
2060         .put_link       = fuse_put_link,
2061         .readlink       = generic_readlink,
2062         .getattr        = fuse_getattr,
2063         .setxattr       = fuse_setxattr,
2064         .getxattr       = fuse_getxattr,
2065         .listxattr      = fuse_listxattr,
2066         .removexattr    = fuse_removexattr,
2067 };
2068
2069 void fuse_init_common(struct inode *inode)
2070 {
2071         inode->i_op = &fuse_common_inode_operations;
2072 }
2073
2074 void fuse_init_dir(struct inode *inode)
2075 {
2076         inode->i_op = &fuse_dir_inode_operations;
2077         inode->i_fop = &fuse_dir_operations;
2078 }
2079
2080 void fuse_init_symlink(struct inode *inode)
2081 {
2082         inode->i_op = &fuse_symlink_inode_operations;
2083 }