fs/fuse/inode.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/slab.h>
  13 #include <linux/file.h>
  14 #include <linux/seq_file.h>
  15 #include <linux/init.h>
  16 #include <linux/module.h>
  17 #include <linux/parser.h>
  18 #include <linux/statfs.h>
  19 #include <linux/random.h>
  20 #include <linux/sched.h>
  21 #include <linux/exportfs.h>
  22
  23 MODULE_AUTHOR("Miklos Szeredi <miklos@szeredi.hu>");
  24 MODULE_DESCRIPTION("Filesystem in Userspace");
  25 MODULE_LICENSE("GPL");
  26
  27 static struct kmem_cache *fuse_inode_cachep;
  28 struct list_head fuse_conn_list;
  29 DEFINE_MUTEX(fuse_mutex);
  30
  31 #define FUSE_SUPER_MAGIC 0x65735546
  32
  33 #define FUSE_DEFAULT_BLKSIZE 512
  34
  35 struct fuse_mount_data {
  36         int fd;
  37         unsigned rootmode;
  38         unsigned user_id;
  39         unsigned group_id;
  40         unsigned fd_present:1;
  41         unsigned rootmode_present:1;
  42         unsigned user_id_present:1;
  43         unsigned group_id_present:1;
  44         unsigned flags;
  45         unsigned max_read;
  46         unsigned blksize;
  47 };
  48
  49 static struct inode *fuse_alloc_inode(struct super_block *sb)
  50 {
  51         struct inode *inode;
  52         struct fuse_inode *fi;
  53
  54         inode = kmem_cache_alloc(fuse_inode_cachep, GFP_KERNEL);
  55         if (!inode)
  56                 return NULL;
  57
  58         fi = get_fuse_inode(inode);
  59         fi->i_time = 0;
  60         fi->nodeid = 0;
  61         fi->nlookup = 0;
  62         fi->attr_version = 0;
  63         fi->writectr = 0;
  64         INIT_LIST_HEAD(&fi->write_files);
  65         INIT_LIST_HEAD(&fi->queued_writes);
  66         INIT_LIST_HEAD(&fi->writepages);
  67         init_waitqueue_head(&fi->page_waitq);
  68         fi->forget_req = fuse_request_alloc();
  69         if (!fi->forget_req) {
  70                 kmem_cache_free(fuse_inode_cachep, inode);
  71                 return NULL;
  72         }
  73
  74         return inode;
  75 }
  76
  77 static void fuse_destroy_inode(struct inode *inode)
  78 {
  79         struct fuse_inode *fi = get_fuse_inode(inode);
  80         BUG_ON(!list_empty(&fi->write_files));
  81         BUG_ON(!list_empty(&fi->queued_writes));
  82         if (fi->forget_req)
  83                 fuse_request_free(fi->forget_req);
  84         kmem_cache_free(fuse_inode_cachep, inode);
  85 }
  86
  87 void fuse_send_forget(struct fuse_conn *fc, struct fuse_req *req,
  88                       u64 nodeid, u64 nlookup)
  89 {
  90         struct fuse_forget_in *inarg = &req->misc.forget_in;
  91         inarg->nlookup = nlookup;
  92         req->in.h.opcode = FUSE_FORGET;
  93         req->in.h.nodeid = nodeid;
  94         req->in.numargs = 1;
  95         req->in.args[0].size = sizeof(struct fuse_forget_in);
  96         req->in.args[0].value = inarg;
  97         fuse_request_send_noreply(fc, req);
  98 }
  99
 100 static void fuse_clear_inode(struct inode *inode)
 101 {
 102         if (inode->i_sb->s_flags & MS_ACTIVE) {
 103                 struct fuse_conn *fc = get_fuse_conn(inode);
 104                 struct fuse_inode *fi = get_fuse_inode(inode);
 105                 fuse_send_forget(fc, fi->forget_req, fi->nodeid, fi->nlookup);
 106                 fi->forget_req = NULL;
 107         }
 108 }
 109
 110 static int fuse_remount_fs(struct super_block *sb, int *flags, char *data)
 111 {
 112         if (*flags & MS_MANDLOCK)
 113                 return -EINVAL;
 114
 115         return 0;
 116 }
 117
 118 void fuse_truncate(struct address_space *mapping, loff_t offset)
 119 {
 120         /* See vmtruncate() */
 121         unmap_mapping_range(mapping, offset + PAGE_SIZE - 1, 0, 1);
 122         truncate_inode_pages(mapping, offset);
 123         unmap_mapping_range(mapping, offset + PAGE_SIZE - 1, 0, 1);
 124 }
 125
 126 void fuse_change_attributes_common(struct inode *inode, struct fuse_attr *attr,
 127                                    u64 attr_valid)
 128 {
 129         struct fuse_conn *fc = get_fuse_conn(inode);
 130         struct fuse_inode *fi = get_fuse_inode(inode);
 131
 132         fi->attr_version = ++fc->attr_version;
 133         fi->i_time = attr_valid;
 134
 135         inode->i_ino     = attr->ino;
 136         inode->i_mode    = (inode->i_mode & S_IFMT) | (attr->mode & 07777);
 137         inode->i_nlink   = attr->nlink;
 138         inode->i_uid     = attr->uid;
 139         inode->i_gid     = attr->gid;
 140         inode->i_blocks  = attr->blocks;
 141         inode->i_atime.tv_sec   = attr->atime;
 142         inode->i_atime.tv_nsec  = attr->atimensec;
 143         inode->i_mtime.tv_sec   = attr->mtime;
 144         inode->i_mtime.tv_nsec  = attr->mtimensec;
 145         inode->i_ctime.tv_sec   = attr->ctime;
 146         inode->i_ctime.tv_nsec  = attr->ctimensec;
 147
 148         if (attr->blksize != 0)
 149                 inode->i_blkbits = ilog2(attr->blksize);
 150         else
 151                 inode->i_blkbits = inode->i_sb->s_blocksize_bits;
 152
 153         /*
 154          * Don't set the sticky bit in i_mode, unless we want the VFS
 155          * to check permissions.  This prevents failures due to the
 156          * check in may_delete().
 157          */
 158         fi->orig_i_mode = inode->i_mode;
 159         if (!(fc->flags & FUSE_DEFAULT_PERMISSIONS))
 160                 inode->i_mode &= ~S_ISVTX;
 161 }
 162
 163 void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr,
 164                             u64 attr_valid, u64 attr_version)
 165 {
 166         struct fuse_conn *fc = get_fuse_conn(inode);
 167         struct fuse_inode *fi = get_fuse_inode(inode);
 168         loff_t oldsize;
 169
 170         spin_lock(&fc->lock);
 171         if (attr_version != 0 && fi->attr_version > attr_version) {
 172                 spin_unlock(&fc->lock);
 173                 return;
 174         }
 175
 176         fuse_change_attributes_common(inode, attr, attr_valid);
 177
 178         oldsize = inode->i_size;
 179         i_size_write(inode, attr->size);
 180         spin_unlock(&fc->lock);
 181
 182         if (S_ISREG(inode->i_mode) && oldsize != attr->size) {
 183                 if (attr->size < oldsize)
 184                         fuse_truncate(inode->i_mapping, attr->size);
 185                 invalidate_inode_pages2(inode->i_mapping);
 186         }
 187 }
 188
 189 static void fuse_init_inode(struct inode *inode, struct fuse_attr *attr)
 190 {
 191         inode->i_mode = attr->mode & S_IFMT;
 192         inode->i_size = attr->size;
 193         if (S_ISREG(inode->i_mode)) {
 194                 fuse_init_common(inode);
 195                 fuse_init_file_inode(inode);
 196         } else if (S_ISDIR(inode->i_mode))
 197                 fuse_init_dir(inode);
 198         else if (S_ISLNK(inode->i_mode))
 199                 fuse_init_symlink(inode);
 200         else if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode) ||
 201                  S_ISFIFO(inode->i_mode) || S_ISSOCK(inode->i_mode)) {
 202                 fuse_init_common(inode);
 203                 init_special_inode(inode, inode->i_mode,
 204                                    new_decode_dev(attr->rdev));
 205         } else
 206                 BUG();
 207 }
 208
 209 static int fuse_inode_eq(struct inode *inode, void *_nodeidp)
 210 {
 211         u64 nodeid = *(u64 *) _nodeidp;
 212         if (get_node_id(inode) == nodeid)
 213                 return 1;
 214         else
 215                 return 0;
 216 }
 217
 218 static int fuse_inode_set(struct inode *inode, void *_nodeidp)
 219 {
 220         u64 nodeid = *(u64 *) _nodeidp;
 221         get_fuse_inode(inode)->nodeid = nodeid;
 222         return 0;
 223 }
 224
 225 struct inode *fuse_iget(struct super_block *sb, u64 nodeid,
 226                         int generation, struct fuse_attr *attr,
 227                         u64 attr_valid, u64 attr_version)
 228 {
 229         struct inode *inode;
 230         struct fuse_inode *fi;
 231         struct fuse_conn *fc = get_fuse_conn_super(sb);
 232
 233  retry:
 234         inode = iget5_locked(sb, nodeid, fuse_inode_eq, fuse_inode_set, &nodeid);
 235         if (!inode)
 236                 return NULL;
 237
 238         if ((inode->i_state & I_NEW)) {
 239                 inode->i_flags |= S_NOATIME|S_NOCMTIME;
 240                 inode->i_generation = generation;
 241                 inode->i_data.backing_dev_info = &fc->bdi;
 242                 fuse_init_inode(inode, attr);
 243                 unlock_new_inode(inode);
 244         } else if ((inode->i_mode ^ attr->mode) & S_IFMT) {
 245                 /* Inode has changed type, any I/O on the old should fail */
 246                 make_bad_inode(inode);
 247                 iput(inode);
 248                 goto retry;
 249         }
 250
 251         fi = get_fuse_inode(inode);
 252         spin_lock(&fc->lock);
 253         fi->nlookup++;
 254         spin_unlock(&fc->lock);
 255         fuse_change_attributes(inode, attr, attr_valid, attr_version);
 256
 257         return inode;
 258 }
 259
 260 static void fuse_umount_begin(struct super_block *sb)
 261 {
 262         fuse_abort_conn(get_fuse_conn_super(sb));
 263 }
 264
 265 static void fuse_send_destroy(struct fuse_conn *fc)
 266 {
 267         struct fuse_req *req = fc->destroy_req;
 268         if (req && fc->conn_init) {
 269                 fc->destroy_req = NULL;
 270                 req->in.h.opcode = FUSE_DESTROY;
 271                 req->force = 1;
 272                 fuse_request_send(fc, req);
 273                 fuse_put_request(fc, req);
 274         }
 275 }
 276
 277 static void fuse_put_super(struct super_block *sb)
 278 {
 279         struct fuse_conn *fc = get_fuse_conn_super(sb);
 280
 281         fuse_send_destroy(fc);
 282         spin_lock(&fc->lock);
 283         fc->connected = 0;
 284         fc->blocked = 0;
 285         spin_unlock(&fc->lock);
 286         /* Flush all readers on this fs */
 287         kill_fasync(&fc->fasync, SIGIO, POLL_IN);
 288         wake_up_all(&fc->waitq);
 289         wake_up_all(&fc->blocked_waitq);
 290         wake_up_all(&fc->reserved_req_waitq);
 291         mutex_lock(&fuse_mutex);
 292         list_del(&fc->entry);
 293         fuse_ctl_remove_conn(fc);
 294         mutex_unlock(&fuse_mutex);
 295         bdi_destroy(&fc->bdi);
 296         fuse_conn_put(fc);
 297 }
 298
 299 static void convert_fuse_statfs(struct kstatfs *stbuf, struct fuse_kstatfs *attr)
 300 {
 301         stbuf->f_type    = FUSE_SUPER_MAGIC;
 302         stbuf->f_bsize   = attr->bsize;
 303         stbuf->f_frsize  = attr->frsize;
 304         stbuf->f_blocks  = attr->blocks;
 305         stbuf->f_bfree   = attr->bfree;
 306         stbuf->f_bavail  = attr->bavail;
 307         stbuf->f_files   = attr->files;
 308         stbuf->f_ffree   = attr->ffree;
 309         stbuf->f_namelen = attr->namelen;
 310         /* fsid is left zero */
 311 }
 312
 313 static int fuse_statfs(struct dentry *dentry, struct kstatfs *buf)
 314 {
 315         struct super_block *sb = dentry->d_sb;
 316         struct fuse_conn *fc = get_fuse_conn_super(sb);
 317         struct fuse_req *req;
 318         struct fuse_statfs_out outarg;
 319         int err;
 320
 321         if (!fuse_allow_task(fc, current)) {
 322                 buf->f_type = FUSE_SUPER_MAGIC;
 323                 return 0;
 324         }
 325
 326         req = fuse_get_req(fc);
 327         if (IS_ERR(req))
 328                 return PTR_ERR(req);
 329
 330         memset(&outarg, 0, sizeof(outarg));
 331         req->in.numargs = 0;
 332         req->in.h.opcode = FUSE_STATFS;
 333         req->in.h.nodeid = get_node_id(dentry->d_inode);
 334         req->out.numargs = 1;
 335         req->out.args[0].size =
 336                 fc->minor < 4 ? FUSE_COMPAT_STATFS_SIZE : sizeof(outarg);
 337         req->out.args[0].value = &outarg;
 338         fuse_request_send(fc, req);
 339         err = req->out.h.error;
 340         if (!err)
 341                 convert_fuse_statfs(buf, &outarg.st);
 342         fuse_put_request(fc, req);
 343         return err;
 344 }
 345
 346 enum {
 347         OPT_FD,
 348         OPT_ROOTMODE,
 349         OPT_USER_ID,
 350         OPT_GROUP_ID,
 351         OPT_DEFAULT_PERMISSIONS,
 352         OPT_ALLOW_OTHER,
 353         OPT_MAX_READ,
 354         OPT_BLKSIZE,
 355         OPT_ERR
 356 };
 357
 358 static const match_table_t tokens = {
 359         {OPT_FD,                        "fd=%u"},
 360         {OPT_ROOTMODE,                  "rootmode=%o"},
 361         {OPT_USER_ID,                   "user_id=%u"},
 362         {OPT_GROUP_ID,                  "group_id=%u"},
 363         {OPT_DEFAULT_PERMISSIONS,       "default_permissions"},
 364         {OPT_ALLOW_OTHER,               "allow_other"},
 365         {OPT_MAX_READ,                  "max_read=%u"},
 366         {OPT_BLKSIZE,                   "blksize=%u"},
 367         {OPT_ERR,                       NULL}
 368 };
 369
 370 static int parse_fuse_opt(char *opt, struct fuse_mount_data *d, int is_bdev)
 371 {
 372         char *p;
 373         memset(d, 0, sizeof(struct fuse_mount_data));
 374         d->max_read = ~0;
 375         d->blksize = FUSE_DEFAULT_BLKSIZE;
 376
 377         while ((p = strsep(&opt, ",")) != NULL) {
 378                 int token;
 379                 int value;
 380                 substring_t args[MAX_OPT_ARGS];
 381                 if (!*p)
 382                         continue;
 383
 384                 token = match_token(p, tokens, args);
 385                 switch (token) {
 386                 case OPT_FD:
 387                         if (match_int(&args[0], &value))
 388                                 return 0;
 389                         d->fd = value;
 390                         d->fd_present = 1;
 391                         break;
 392
 393                 case OPT_ROOTMODE:
 394                         if (match_octal(&args[0], &value))
 395                                 return 0;
 396                         if (!fuse_valid_type(value))
 397                                 return 0;
 398                         d->rootmode = value;
 399                         d->rootmode_present = 1;
 400                         break;
 401
 402                 case OPT_USER_ID:
 403                         if (match_int(&args[0], &value))
 404                                 return 0;
 405                         d->user_id = value;
 406                         d->user_id_present = 1;
 407                         break;
 408
 409                 case OPT_GROUP_ID:
 410                         if (match_int(&args[0], &value))
 411                                 return 0;
 412                         d->group_id = value;
 413                         d->group_id_present = 1;
 414                         break;
 415
 416                 case OPT_DEFAULT_PERMISSIONS:
 417                         d->flags |= FUSE_DEFAULT_PERMISSIONS;
 418                         break;
 419
 420                 case OPT_ALLOW_OTHER:
 421                         d->flags |= FUSE_ALLOW_OTHER;
 422                         break;
 423
 424                 case OPT_MAX_READ:
 425                         if (match_int(&args[0], &value))
 426                                 return 0;
 427                         d->max_read = value;
 428                         break;
 429
 430                 case OPT_BLKSIZE:
 431                         if (!is_bdev || match_int(&args[0], &value))
 432                                 return 0;
 433                         d->blksize = value;
 434                         break;
 435
 436                 default:
 437                         return 0;
 438                 }
 439         }
 440
 441         if (!d->fd_present || !d->rootmode_present ||
 442             !d->user_id_present || !d->group_id_present)
 443                 return 0;
 444
 445         return 1;
 446 }
 447
 448 static int fuse_show_options(struct seq_file *m, struct vfsmount *mnt)
 449 {
 450         struct fuse_conn *fc = get_fuse_conn_super(mnt->mnt_sb);
 451
 452         seq_printf(m, ",user_id=%u", fc->user_id);
 453         seq_printf(m, ",group_id=%u", fc->group_id);
 454         if (fc->flags & FUSE_DEFAULT_PERMISSIONS)
 455                 seq_puts(m, ",default_permissions");
 456         if (fc->flags & FUSE_ALLOW_OTHER)
 457                 seq_puts(m, ",allow_other");
 458         if (fc->max_read != ~0)
 459                 seq_printf(m, ",max_read=%u", fc->max_read);
 460         if (mnt->mnt_sb->s_bdev &&
 461             mnt->mnt_sb->s_blocksize != FUSE_DEFAULT_BLKSIZE)
 462                 seq_printf(m, ",blksize=%lu", mnt->mnt_sb->s_blocksize);
 463         return 0;
 464 }
 465
 466 int fuse_conn_init(struct fuse_conn *fc, struct super_block *sb)
 467 {
 468         int err;
 469
 470         memset(fc, 0, sizeof(*fc));
 471         spin_lock_init(&fc->lock);
 472         mutex_init(&fc->inst_mutex);
 473         atomic_set(&fc->count, 1);
 474         init_waitqueue_head(&fc->waitq);
 475         init_waitqueue_head(&fc->blocked_waitq);
 476         init_waitqueue_head(&fc->reserved_req_waitq);
 477         INIT_LIST_HEAD(&fc->pending);
 478         INIT_LIST_HEAD(&fc->processing);
 479         INIT_LIST_HEAD(&fc->io);
 480         INIT_LIST_HEAD(&fc->interrupts);
 481         INIT_LIST_HEAD(&fc->bg_queue);
 482         INIT_LIST_HEAD(&fc->entry);
 483         atomic_set(&fc->num_waiting, 0);
 484         fc->bdi.ra_pages = (VM_MAX_READAHEAD * 1024) / PAGE_CACHE_SIZE;
 485         fc->bdi.unplug_io_fn = default_unplug_io_fn;
 486         /* fuse does it's own writeback accounting */
 487         fc->bdi.capabilities = BDI_CAP_NO_ACCT_WB;
 488         fc->khctr = 0;
 489         fc->polled_files = RB_ROOT;
 490         fc->dev = sb->s_dev;
 491         err = bdi_init(&fc->bdi);
 492         if (err)
 493                 goto error_mutex_destroy;
 494         if (sb->s_bdev) {
 495                 err = bdi_register(&fc->bdi, NULL, "%u:%u-fuseblk",
 496                                    MAJOR(fc->dev), MINOR(fc->dev));
 497         } else {
 498                 err = bdi_register_dev(&fc->bdi, fc->dev);
 499         }
 500         if (err)
 501                 goto error_bdi_destroy;
 502         /*
 503          * For a single fuse filesystem use max 1% of dirty +
 504          * writeback threshold.
 505          *
 506          * This gives about 1M of write buffer for memory maps on a
 507          * machine with 1G and 10% dirty_ratio, which should be more
 508          * than enough.
 509          *
 510          * Privileged users can raise it by writing to
 511          *
 512          *    /sys/class/bdi/<bdi>/max_ratio
 513          */
 514         bdi_set_max_ratio(&fc->bdi, 1);
 515         fc->reqctr = 0;
 516         fc->blocked = 1;
 517         fc->attr_version = 1;
 518         get_random_bytes(&fc->scramble_key, sizeof(fc->scramble_key));
 519
 520         return 0;
 521
 522  error_bdi_destroy:
 523         bdi_destroy(&fc->bdi);
 524  error_mutex_destroy:
 525         mutex_destroy(&fc->inst_mutex);
 526         return err;
 527 }
 528 EXPORT_SYMBOL_GPL(fuse_conn_init);
 529
 530 void fuse_conn_put(struct fuse_conn *fc)
 531 {
 532         if (atomic_dec_and_test(&fc->count)) {
 533                 if (fc->destroy_req)
 534                         fuse_request_free(fc->destroy_req);
 535                 mutex_destroy(&fc->inst_mutex);
 536                 fc->release(fc);
 537         }
 538 }
 539
 540 struct fuse_conn *fuse_conn_get(struct fuse_conn *fc)
 541 {
 542         atomic_inc(&fc->count);
 543         return fc;
 544 }
 545
 546 static struct inode *fuse_get_root_inode(struct super_block *sb, unsigned mode)
 547 {
 548         struct fuse_attr attr;
 549         memset(&attr, 0, sizeof(attr));
 550
 551         attr.mode = mode;
 552         attr.ino = FUSE_ROOT_ID;
 553         attr.nlink = 1;
 554         return fuse_iget(sb, 1, 0, &attr, 0, 0);
 555 }
 556
 557 struct fuse_inode_handle {
 558         u64 nodeid;
 559         u32 generation;
 560 };
 561
 562 static struct dentry *fuse_get_dentry(struct super_block *sb,
 563                                       struct fuse_inode_handle *handle)
 564 {
 565         struct fuse_conn *fc = get_fuse_conn_super(sb);
 566         struct inode *inode;
 567         struct dentry *entry;
 568         int err = -ESTALE;
 569
 570         if (handle->nodeid == 0)
 571                 goto out_err;
 572
 573         inode = ilookup5(sb, handle->nodeid, fuse_inode_eq, &handle->nodeid);
 574         if (!inode) {
 575                 struct fuse_entry_out outarg;
 576                 struct qstr name;
 577
 578                 if (!fc->export_support)
 579                         goto out_err;
 580
 581                 name.len = 1;
 582                 name.name = ".";
 583                 err = fuse_lookup_name(sb, handle->nodeid, &name, &outarg,
 584                                        &inode);
 585                 if (err && err != -ENOENT)
 586                         goto out_err;
 587                 if (err || !inode) {
 588                         err = -ESTALE;
 589                         goto out_err;
 590                 }
 591                 err = -EIO;
 592                 if (get_node_id(inode) != handle->nodeid)
 593                         goto out_iput;
 594         }
 595         err = -ESTALE;
 596         if (inode->i_generation != handle->generation)
 597                 goto out_iput;
 598
 599         entry = d_obtain_alias(inode);
 600         if (!IS_ERR(entry) && get_node_id(inode) != FUSE_ROOT_ID) {
 601                 entry->d_op = &fuse_dentry_operations;
 602                 fuse_invalidate_entry_cache(entry);
 603         }
 604
 605         return entry;
 606
 607  out_iput:
 608         iput(inode);
 609  out_err:
 610         return ERR_PTR(err);
 611 }
 612
 613 static int fuse_encode_fh(struct dentry *dentry, u32 *fh, int *max_len,
 614                            int connectable)
 615 {
 616         struct inode *inode = dentry->d_inode;
 617         bool encode_parent = connectable && !S_ISDIR(inode->i_mode);
 618         int len = encode_parent ? 6 : 3;
 619         u64 nodeid;
 620         u32 generation;
 621
 622         if (*max_len < len)
 623                 return  255;
 624
 625         nodeid = get_fuse_inode(inode)->nodeid;
 626         generation = inode->i_generation;
 627
 628         fh[0] = (u32)(nodeid >> 32);
 629         fh[1] = (u32)(nodeid & 0xffffffff);
 630         fh[2] = generation;
 631
 632         if (encode_parent) {
 633                 struct inode *parent;
 634
 635                 spin_lock(&dentry->d_lock);
 636                 parent = dentry->d_parent->d_inode;
 637                 nodeid = get_fuse_inode(parent)->nodeid;
 638                 generation = parent->i_generation;
 639                 spin_unlock(&dentry->d_lock);
 640
 641                 fh[3] = (u32)(nodeid >> 32);
 642                 fh[4] = (u32)(nodeid & 0xffffffff);
 643                 fh[5] = generation;
 644         }
 645
 646         *max_len = len;
 647         return encode_parent ? 0x82 : 0x81;
 648 }
 649
 650 static struct dentry *fuse_fh_to_dentry(struct super_block *sb,
 651                 struct fid *fid, int fh_len, int fh_type)
 652 {
 653         struct fuse_inode_handle handle;
 654
 655         if ((fh_type != 0x81 && fh_type != 0x82) || fh_len < 3)
 656                 return NULL;
 657
 658         handle.nodeid = (u64) fid->raw[0] << 32;
 659         handle.nodeid |= (u64) fid->raw[1];
 660         handle.generation = fid->raw[2];
 661         return fuse_get_dentry(sb, &handle);
 662 }
 663
 664 static struct dentry *fuse_fh_to_parent(struct super_block *sb,
 665                 struct fid *fid, int fh_len, int fh_type)
 666 {
 667         struct fuse_inode_handle parent;
 668
 669         if (fh_type != 0x82 || fh_len < 6)
 670                 return NULL;
 671
 672         parent.nodeid = (u64) fid->raw[3] << 32;
 673         parent.nodeid |= (u64) fid->raw[4];
 674         parent.generation = fid->raw[5];
 675         return fuse_get_dentry(sb, &parent);
 676 }
 677
 678 static struct dentry *fuse_get_parent(struct dentry *child)
 679 {
 680         struct inode *child_inode = child->d_inode;
 681         struct fuse_conn *fc = get_fuse_conn(child_inode);
 682         struct inode *inode;
 683         struct dentry *parent;
 684         struct fuse_entry_out outarg;
 685         struct qstr name;
 686         int err;
 687
 688         if (!fc->export_support)
 689                 return ERR_PTR(-ESTALE);
 690
 691         name.len = 2;
 692         name.name = "..";
 693         err = fuse_lookup_name(child_inode->i_sb, get_node_id(child_inode),
 694                                &name, &outarg, &inode);
 695         if (err) {
 696                 if (err == -ENOENT)
 697                         return ERR_PTR(-ESTALE);
 698                 return ERR_PTR(err);
 699         }
 700
 701         parent = d_obtain_alias(inode);
 702         if (!IS_ERR(parent) && get_node_id(inode) != FUSE_ROOT_ID) {
 703                 parent->d_op = &fuse_dentry_operations;
 704                 fuse_invalidate_entry_cache(parent);
 705         }
 706
 707         return parent;
 708 }
 709
 710 static const struct export_operations fuse_export_operations = {
 711         .fh_to_dentry   = fuse_fh_to_dentry,
 712         .fh_to_parent   = fuse_fh_to_parent,
 713         .encode_fh      = fuse_encode_fh,
 714         .get_parent     = fuse_get_parent,
 715 };
 716
 717 static const struct super_operations fuse_super_operations = {
 718         .alloc_inode    = fuse_alloc_inode,
 719         .destroy_inode  = fuse_destroy_inode,
 720         .clear_inode    = fuse_clear_inode,
 721         .drop_inode     = generic_delete_inode,
 722         .remount_fs     = fuse_remount_fs,
 723         .put_super      = fuse_put_super,
 724         .umount_begin   = fuse_umount_begin,
 725         .statfs         = fuse_statfs,
 726         .show_options   = fuse_show_options,
 727 };
 728
 729 static void process_init_reply(struct fuse_conn *fc, struct fuse_req *req)
 730 {
 731         struct fuse_init_out *arg = &req->misc.init_out;
 732
 733         if (req->out.h.error || arg->major != FUSE_KERNEL_VERSION)
 734                 fc->conn_error = 1;
 735         else {
 736                 unsigned long ra_pages;
 737
 738                 if (arg->minor >= 6) {
 739                         ra_pages = arg->max_readahead / PAGE_CACHE_SIZE;
 740                         if (arg->flags & FUSE_ASYNC_READ)
 741                                 fc->async_read = 1;
 742                         if (!(arg->flags & FUSE_POSIX_LOCKS))
 743                                 fc->no_lock = 1;
 744                         if (arg->flags & FUSE_ATOMIC_O_TRUNC)
 745                                 fc->atomic_o_trunc = 1;
 746                         if (arg->minor >= 9) {
 747                                 /* LOOKUP has dependency on proto version */
 748                                 if (arg->flags & FUSE_EXPORT_SUPPORT)
 749                                         fc->export_support = 1;
 750                         }
 751                         if (arg->flags & FUSE_BIG_WRITES)
 752                                 fc->big_writes = 1;
 753                 } else {
 754                         ra_pages = fc->max_read / PAGE_CACHE_SIZE;
 755                         fc->no_lock = 1;
 756                 }
 757
 758                 fc->bdi.ra_pages = min(fc->bdi.ra_pages, ra_pages);
 759                 fc->minor = arg->minor;
 760                 fc->max_write = arg->minor < 5 ? 4096 : arg->max_write;
 761                 fc->max_write = max_t(unsigned, 4096, fc->max_write);
 762                 fc->conn_init = 1;
 763         }
 764         fc->blocked = 0;
 765         wake_up_all(&fc->blocked_waitq);
 766 }
 767
 768 static void fuse_send_init(struct fuse_conn *fc, struct fuse_req *req)
 769 {
 770         struct fuse_init_in *arg = &req->misc.init_in;
 771
 772         arg->major = FUSE_KERNEL_VERSION;
 773         arg->minor = FUSE_KERNEL_MINOR_VERSION;
 774         arg->max_readahead = fc->bdi.ra_pages * PAGE_CACHE_SIZE;
 775         arg->flags |= FUSE_ASYNC_READ | FUSE_POSIX_LOCKS | FUSE_ATOMIC_O_TRUNC |
 776                 FUSE_EXPORT_SUPPORT | FUSE_BIG_WRITES;
 777         req->in.h.opcode = FUSE_INIT;
 778         req->in.numargs = 1;
 779         req->in.args[0].size = sizeof(*arg);
 780         req->in.args[0].value = arg;
 781         req->out.numargs = 1;
 782         /* Variable length arguement used for backward compatibility
 783            with interface version < 7.5.  Rest of init_out is zeroed
 784            by do_get_request(), so a short reply is not a problem */
 785         req->out.argvar = 1;
 786         req->out.args[0].size = sizeof(struct fuse_init_out);
 787         req->out.args[0].value = &req->misc.init_out;
 788         req->end = process_init_reply;
 789         fuse_request_send_background(fc, req);
 790 }
 791
 792 static void fuse_free_conn(struct fuse_conn *fc)
 793 {
 794         kfree(fc);
 795 }
 796
 797 static int fuse_fill_super(struct super_block *sb, void *data, int silent)
 798 {
 799         struct fuse_conn *fc;
 800         struct inode *root;
 801         struct fuse_mount_data d;
 802         struct file *file;
 803         struct dentry *root_dentry;
 804         struct fuse_req *init_req;
 805         int err;
 806         int is_bdev = sb->s_bdev != NULL;
 807
 808         err = -EINVAL;
 809         if (sb->s_flags & MS_MANDLOCK)
 810                 goto err;
 811
 812         if (!parse_fuse_opt((char *) data, &d, is_bdev))
 813                 goto err;
 814
 815         if (is_bdev) {
 816 #ifdef CONFIG_BLOCK
 817                 err = -EINVAL;
 818                 if (!sb_set_blocksize(sb, d.blksize))
 819                         goto err;
 820 #endif
 821         } else {
 822                 sb->s_blocksize = PAGE_CACHE_SIZE;
 823                 sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
 824         }
 825         sb->s_magic = FUSE_SUPER_MAGIC;
 826         sb->s_op = &fuse_super_operations;
 827         sb->s_maxbytes = MAX_LFS_FILESIZE;
 828         sb->s_export_op = &fuse_export_operations;
 829
 830         file = fget(d.fd);
 831         err = -EINVAL;
 832         if (!file)
 833                 goto err;
 834
 835         if (file->f_op != &fuse_dev_operations)
 836                 goto err_fput;
 837
 838         fc = kmalloc(sizeof(*fc), GFP_KERNEL);
 839         err = -ENOMEM;
 840         if (!fc)
 841                 goto err_fput;
 842
 843         err = fuse_conn_init(fc, sb);
 844         if (err) {
 845                 kfree(fc);
 846                 goto err_fput;
 847         }
 848
 849         fc->release = fuse_free_conn;
 850         fc->flags = d.flags;
 851         fc->user_id = d.user_id;
 852         fc->group_id = d.group_id;
 853         fc->max_read = max_t(unsigned, 4096, d.max_read);
 854
 855         /* Used by get_root_inode() */
 856         sb->s_fs_info = fc;
 857
 858         err = -ENOMEM;
 859         root = fuse_get_root_inode(sb, d.rootmode);
 860         if (!root)
 861                 goto err_put_conn;
 862
 863         root_dentry = d_alloc_root(root);
 864         if (!root_dentry) {
 865                 iput(root);
 866                 goto err_put_conn;
 867         }
 868
 869         init_req = fuse_request_alloc();
 870         if (!init_req)
 871                 goto err_put_root;
 872
 873         if (is_bdev) {
 874                 fc->destroy_req = fuse_request_alloc();
 875                 if (!fc->destroy_req)
 876                         goto err_free_init_req;
 877         }
 878
 879         mutex_lock(&fuse_mutex);
 880         err = -EINVAL;
 881         if (file->private_data)
 882                 goto err_unlock;
 883
 884         err = fuse_ctl_add_conn(fc);
 885         if (err)
 886                 goto err_unlock;
 887
 888         list_add_tail(&fc->entry, &fuse_conn_list);
 889         sb->s_root = root_dentry;
 890         fc->connected = 1;
 891         file->private_data = fuse_conn_get(fc);
 892         mutex_unlock(&fuse_mutex);
 893         /*
 894          * atomic_dec_and_test() in fput() provides the necessary
 895          * memory barrier for file->private_data to be visible on all
 896          * CPUs after this
 897          */
 898         fput(file);
 899
 900         fuse_send_init(fc, init_req);
 901
 902         return 0;
 903
 904  err_unlock:
 905         mutex_unlock(&fuse_mutex);
 906  err_free_init_req:
 907         fuse_request_free(init_req);
 908  err_put_root:
 909         dput(root_dentry);
 910  err_put_conn:
 911         fuse_conn_put(fc);
 912  err_fput:
 913         fput(file);
 914  err:
 915         return err;
 916 }
 917
 918 static int fuse_get_sb(struct file_system_type *fs_type,
 919                        int flags, const char *dev_name,
 920                        void *raw_data, struct vfsmount *mnt)
 921 {
 922         return get_sb_nodev(fs_type, flags, raw_data, fuse_fill_super, mnt);
 923 }
 924
 925 static struct file_system_type fuse_fs_type = {
 926         .owner          = THIS_MODULE,
 927         .name           = "fuse",
 928         .fs_flags       = FS_HAS_SUBTYPE,
 929         .get_sb         = fuse_get_sb,
 930         .kill_sb        = kill_anon_super,
 931 };
 932
 933 #ifdef CONFIG_BLOCK
 934 static int fuse_get_sb_blk(struct file_system_type *fs_type,
 935                            int flags, const char *dev_name,
 936                            void *raw_data, struct vfsmount *mnt)
 937 {
 938         return get_sb_bdev(fs_type, flags, dev_name, raw_data, fuse_fill_super,
 939                            mnt);
 940 }
 941
 942 static struct file_system_type fuseblk_fs_type = {
 943         .owner          = THIS_MODULE,
 944         .name           = "fuseblk",
 945         .get_sb         = fuse_get_sb_blk,
 946         .kill_sb        = kill_block_super,
 947         .fs_flags       = FS_REQUIRES_DEV | FS_HAS_SUBTYPE,
 948 };
 949
 950 static inline int register_fuseblk(void)
 951 {
 952         return register_filesystem(&fuseblk_fs_type);
 953 }
 954
 955 static inline void unregister_fuseblk(void)
 956 {
 957         unregister_filesystem(&fuseblk_fs_type);
 958 }
 959 #else
 960 static inline int register_fuseblk(void)
 961 {
 962         return 0;
 963 }
 964
 965 static inline void unregister_fuseblk(void)
 966 {
 967 }
 968 #endif
 969
 970 static void fuse_inode_init_once(void *foo)
 971 {
 972         struct inode *inode = foo;
 973
 974         inode_init_once(inode);
 975 }
 976
 977 static int __init fuse_fs_init(void)
 978 {
 979         int err;
 980
 981         err = register_filesystem(&fuse_fs_type);
 982         if (err)
 983                 goto out;
 984
 985         err = register_fuseblk();
 986         if (err)
 987                 goto out_unreg;
 988
 989         fuse_inode_cachep = kmem_cache_create("fuse_inode",
 990                                               sizeof(struct fuse_inode),
 991                                               0, SLAB_HWCACHE_ALIGN,
 992                                               fuse_inode_init_once);
 993         err = -ENOMEM;
 994         if (!fuse_inode_cachep)
 995                 goto out_unreg2;
 996
 997         return 0;
 998
 999  out_unreg2:
1000         unregister_fuseblk();
1001  out_unreg:
1002         unregister_filesystem(&fuse_fs_type);
1003  out:
1004         return err;
1005 }
1006
1007 static void fuse_fs_cleanup(void)
1008 {
1009         unregister_filesystem(&fuse_fs_type);
1010         unregister_fuseblk();
1011         kmem_cache_destroy(fuse_inode_cachep);
1012 }
1013
1014 static struct kobject *fuse_kobj;
1015 static struct kobject *connections_kobj;
1016
1017 static int fuse_sysfs_init(void)
1018 {
1019         int err;
1020
1021         fuse_kobj = kobject_create_and_add("fuse", fs_kobj);
1022         if (!fuse_kobj) {
1023                 err = -ENOMEM;
1024                 goto out_err;
1025         }
1026
1027         connections_kobj = kobject_create_and_add("connections", fuse_kobj);
1028         if (!connections_kobj) {
1029                 err = -ENOMEM;
1030                 goto out_fuse_unregister;
1031         }
1032
1033         return 0;
1034
1035  out_fuse_unregister:
1036         kobject_put(fuse_kobj);
1037  out_err:
1038         return err;
1039 }
1040
1041 static void fuse_sysfs_cleanup(void)
1042 {
1043         kobject_put(connections_kobj);
1044         kobject_put(fuse_kobj);
1045 }
1046
1047 static int __init fuse_init(void)
1048 {
1049         int res;
1050
1051         printk(KERN_INFO "fuse init (API version %i.%i)\n",
1052                FUSE_KERNEL_VERSION, FUSE_KERNEL_MINOR_VERSION);
1053
1054         INIT_LIST_HEAD(&fuse_conn_list);
1055         res = fuse_fs_init();
1056         if (res)
1057                 goto err;
1058
1059         res = fuse_dev_init();
1060         if (res)
1061                 goto err_fs_cleanup;
1062
1063         res = fuse_sysfs_init();
1064         if (res)
1065                 goto err_dev_cleanup;
1066
1067         res = fuse_ctl_init();
1068         if (res)
1069                 goto err_sysfs_cleanup;
1070
1071         return 0;
1072
1073  err_sysfs_cleanup:
1074         fuse_sysfs_cleanup();
1075  err_dev_cleanup:
1076         fuse_dev_cleanup();
1077  err_fs_cleanup:
1078         fuse_fs_cleanup();
1079  err:
1080         return res;
1081 }
1082
1083 static void __exit fuse_exit(void)
1084 {
1085         printk(KERN_DEBUG "fuse exit\n");
1086
1087         fuse_ctl_cleanup();
1088         fuse_sysfs_cleanup();
1089         fuse_fs_cleanup();
1090         fuse_dev_cleanup();
1091 }
1092
1093 module_init(fuse_init);
1094 module_exit(fuse_exit);