fs/fuse/inode.c

   1 /*
   2   FUSE: Filesystem in Userspace
   3   Copyright (C) 2001-2006  Miklos Szeredi <miklos@szeredi.hu>
   4
   5   This program can be distributed under the terms of the GNU GPL.
   6   See the file COPYING.
   7 */
   8
   9 #include "fuse_i.h"
  10
  11 #include <linux/pagemap.h>
  12 #include <linux/slab.h>
  13 #include <linux/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
  22 MODULE_AUTHOR("Miklos Szeredi <miklos@szeredi.hu>");
  23 MODULE_DESCRIPTION("Filesystem in Userspace");
  24 MODULE_LICENSE("GPL");
  25
  26 static struct kmem_cache *fuse_inode_cachep;
  27 struct list_head fuse_conn_list;
  28 DEFINE_MUTEX(fuse_mutex);
  29
  30 #define FUSE_SUPER_MAGIC 0x65735546
  31
  32 #define FUSE_DEFAULT_BLKSIZE 512
  33
  34 struct fuse_mount_data {
  35         int fd;
  36         unsigned rootmode;
  37         unsigned user_id;
  38         unsigned group_id;
  39         unsigned fd_present : 1;
  40         unsigned rootmode_present : 1;
  41         unsigned user_id_present : 1;
  42         unsigned group_id_present : 1;
  43         unsigned flags;
  44         unsigned max_read;
  45         unsigned blksize;
  46 };
  47
  48 static struct inode *fuse_alloc_inode(struct super_block *sb)
  49 {
  50         struct inode *inode;
  51         struct fuse_inode *fi;
  52
  53         inode = kmem_cache_alloc(fuse_inode_cachep, GFP_KERNEL);
  54         if (!inode)
  55                 return NULL;
  56
  57         fi = get_fuse_inode(inode);
  58         fi->i_time = 0;
  59         fi->nodeid = 0;
  60         fi->nlookup = 0;
  61         fi->attr_version = 0;
  62         fi->writectr = 0;
  63         INIT_LIST_HEAD(&fi->write_files);
  64         INIT_LIST_HEAD(&fi->queued_writes);
  65         INIT_LIST_HEAD(&fi->writepages);
  66         init_waitqueue_head(&fi->page_waitq);
  67         fi->forget_req = fuse_request_alloc();
  68         if (!fi->forget_req) {
  69                 kmem_cache_free(fuse_inode_cachep, inode);
  70                 return NULL;
  71         }
  72
  73         return inode;
  74 }
  75
  76 static void fuse_destroy_inode(struct inode *inode)
  77 {
  78         struct fuse_inode *fi = get_fuse_inode(inode);
  79         BUG_ON(!list_empty(&fi->write_files));
  80         BUG_ON(!list_empty(&fi->queued_writes));
  81         if (fi->forget_req)
  82                 fuse_request_free(fi->forget_req);
  83         kmem_cache_free(fuse_inode_cachep, inode);
  84 }
  85
  86 void fuse_send_forget(struct fuse_conn *fc, struct fuse_req *req,
  87                       u64 nodeid, u64 nlookup)
  88 {
  89         struct fuse_forget_in *inarg = &req->misc.forget_in;
  90         inarg->nlookup = nlookup;
  91         req->in.h.opcode = FUSE_FORGET;
  92         req->in.h.nodeid = nodeid;
  93         req->in.numargs = 1;
  94         req->in.args[0].size = sizeof(struct fuse_forget_in);
  95         req->in.args[0].value = inarg;
  96         request_send_noreply(fc, req);
  97 }
  98
  99 static void fuse_clear_inode(struct inode *inode)
 100 {
 101         if (inode->i_sb->s_flags & MS_ACTIVE) {
 102                 struct fuse_conn *fc = get_fuse_conn(inode);
 103                 struct fuse_inode *fi = get_fuse_inode(inode);
 104                 fuse_send_forget(fc, fi->forget_req, fi->nodeid, fi->nlookup);
 105                 fi->forget_req = NULL;
 106         }
 107 }
 108
 109 static int fuse_remount_fs(struct super_block *sb, int *flags, char *data)
 110 {
 111         if (*flags & MS_MANDLOCK)
 112                 return -EINVAL;
 113
 114         return 0;
 115 }
 116
 117 void fuse_truncate(struct address_space *mapping, loff_t offset)
 118 {
 119         /* See vmtruncate() */
 120         unmap_mapping_range(mapping, offset + PAGE_SIZE - 1, 0, 1);
 121         truncate_inode_pages(mapping, offset);
 122         unmap_mapping_range(mapping, offset + PAGE_SIZE - 1, 0, 1);
 123 }
 124
 125 void fuse_change_attributes_common(struct inode *inode, struct fuse_attr *attr,
 126                                    u64 attr_valid)
 127 {
 128         struct fuse_conn *fc = get_fuse_conn(inode);
 129         struct fuse_inode *fi = get_fuse_inode(inode);
 130
 131         fi->attr_version = ++fc->attr_version;
 132         fi->i_time = attr_valid;
 133
 134         inode->i_ino     = attr->ino;
 135         inode->i_mode    = (inode->i_mode & S_IFMT) | (attr->mode & 07777);
 136         inode->i_nlink   = attr->nlink;
 137         inode->i_uid     = attr->uid;
 138         inode->i_gid     = attr->gid;
 139         inode->i_blocks  = attr->blocks;
 140         inode->i_atime.tv_sec   = attr->atime;
 141         inode->i_atime.tv_nsec  = attr->atimensec;
 142         inode->i_mtime.tv_sec   = attr->mtime;
 143         inode->i_mtime.tv_nsec  = attr->mtimensec;
 144         inode->i_ctime.tv_sec   = attr->ctime;
 145         inode->i_ctime.tv_nsec  = attr->ctimensec;
 146
 147         if (attr->blksize != 0)
 148                 inode->i_blkbits = ilog2(attr->blksize);
 149         else
 150                 inode->i_blkbits = inode->i_sb->s_blocksize_bits;
 151
 152         /*
 153          * Don't set the sticky bit in i_mode, unless we want the VFS
 154          * to check permissions.  This prevents failures due to the
 155          * check in may_delete().
 156          */
 157         fi->orig_i_mode = inode->i_mode;
 158         if (!(fc->flags & FUSE_DEFAULT_PERMISSIONS))
 159                 inode->i_mode &= ~S_ISVTX;
 160 }
 161
 162 void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr,
 163                             u64 attr_valid, u64 attr_version)
 164 {
 165         struct fuse_conn *fc = get_fuse_conn(inode);
 166         struct fuse_inode *fi = get_fuse_inode(inode);
 167         loff_t oldsize;
 168
 169         spin_lock(&fc->lock);
 170         if (attr_version != 0 && fi->attr_version > attr_version) {
 171                 spin_unlock(&fc->lock);
 172                 return;
 173         }
 174
 175         fuse_change_attributes_common(inode, attr, attr_valid);
 176
 177         oldsize = inode->i_size;
 178         i_size_write(inode, attr->size);
 179         spin_unlock(&fc->lock);
 180
 181         if (S_ISREG(inode->i_mode) && oldsize != attr->size) {
 182                 if (attr->size < oldsize)
 183                         fuse_truncate(inode->i_mapping, attr->size);
 184                 invalidate_inode_pages2(inode->i_mapping);
 185         }
 186 }
 187
 188 static void fuse_init_inode(struct inode *inode, struct fuse_attr *attr)
 189 {
 190         inode->i_mode = attr->mode & S_IFMT;
 191         inode->i_size = attr->size;
 192         if (S_ISREG(inode->i_mode)) {
 193                 fuse_init_common(inode);
 194                 fuse_init_file_inode(inode);
 195         } else if (S_ISDIR(inode->i_mode))
 196                 fuse_init_dir(inode);
 197         else if (S_ISLNK(inode->i_mode))
 198                 fuse_init_symlink(inode);
 199         else if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode) ||
 200                  S_ISFIFO(inode->i_mode) || S_ISSOCK(inode->i_mode)) {
 201                 fuse_init_common(inode);
 202                 init_special_inode(inode, inode->i_mode,
 203                                    new_decode_dev(attr->rdev));
 204         } else
 205                 BUG();
 206 }
 207
 208 static int fuse_inode_eq(struct inode *inode, void *_nodeidp)
 209 {
 210         u64 nodeid = *(u64 *) _nodeidp;
 211         if (get_node_id(inode) == nodeid)
 212                 return 1;
 213         else
 214                 return 0;
 215 }
 216
 217 static int fuse_inode_set(struct inode *inode, void *_nodeidp)
 218 {
 219         u64 nodeid = *(u64 *) _nodeidp;
 220         get_fuse_inode(inode)->nodeid = nodeid;
 221         return 0;
 222 }
 223
 224 struct inode *fuse_iget(struct super_block *sb, u64 nodeid,
 225                         int generation, struct fuse_attr *attr,
 226                         u64 attr_valid, u64 attr_version)
 227 {
 228         struct inode *inode;
 229         struct fuse_inode *fi;
 230         struct fuse_conn *fc = get_fuse_conn_super(sb);
 231
 232  retry:
 233         inode = iget5_locked(sb, nodeid, fuse_inode_eq, fuse_inode_set, &nodeid);
 234         if (!inode)
 235                 return NULL;
 236
 237         if ((inode->i_state & I_NEW)) {
 238                 inode->i_flags |= S_NOATIME|S_NOCMTIME;
 239                 inode->i_generation = generation;
 240                 inode->i_data.backing_dev_info = &fc->bdi;
 241                 fuse_init_inode(inode, attr);
 242                 unlock_new_inode(inode);
 243         } else if ((inode->i_mode ^ attr->mode) & S_IFMT) {
 244                 /* Inode has changed type, any I/O on the old should fail */
 245                 make_bad_inode(inode);
 246                 iput(inode);
 247                 goto retry;
 248         }
 249
 250         fi = get_fuse_inode(inode);
 251         spin_lock(&fc->lock);
 252         fi->nlookup ++;
 253         spin_unlock(&fc->lock);
 254         fuse_change_attributes(inode, attr, attr_valid, attr_version);
 255
 256         return inode;
 257 }
 258
 259 static void fuse_umount_begin(struct super_block *sb)
 260 {
 261         fuse_abort_conn(get_fuse_conn_super(sb));
 262 }
 263
 264 static void fuse_send_destroy(struct fuse_conn *fc)
 265 {
 266         struct fuse_req *req = fc->destroy_req;
 267         if (req && fc->conn_init) {
 268                 fc->destroy_req = NULL;
 269                 req->in.h.opcode = FUSE_DESTROY;
 270                 req->force = 1;
 271                 request_send(fc, req);
 272                 fuse_put_request(fc, req);
 273         }
 274 }
 275
 276 static void fuse_put_super(struct super_block *sb)
 277 {
 278         struct fuse_conn *fc = get_fuse_conn_super(sb);
 279
 280         fuse_send_destroy(fc);
 281         spin_lock(&fc->lock);
 282         fc->connected = 0;
 283         fc->blocked = 0;
 284         spin_unlock(&fc->lock);
 285         /* Flush all readers on this fs */
 286         kill_fasync(&fc->fasync, SIGIO, POLL_IN);
 287         wake_up_all(&fc->waitq);
 288         wake_up_all(&fc->blocked_waitq);
 289         wake_up_all(&fc->reserved_req_waitq);
 290         mutex_lock(&fuse_mutex);
 291         list_del(&fc->entry);
 292         fuse_ctl_remove_conn(fc);
 293         mutex_unlock(&fuse_mutex);
 294         fuse_conn_put(fc);
 295 }
 296
 297 static void convert_fuse_statfs(struct kstatfs *stbuf, struct fuse_kstatfs *attr)
 298 {
 299         stbuf->f_type    = FUSE_SUPER_MAGIC;
 300         stbuf->f_bsize   = attr->bsize;
 301         stbuf->f_frsize  = attr->frsize;
 302         stbuf->f_blocks  = attr->blocks;
 303         stbuf->f_bfree   = attr->bfree;
 304         stbuf->f_bavail  = attr->bavail;
 305         stbuf->f_files   = attr->files;
 306         stbuf->f_ffree   = attr->ffree;
 307         stbuf->f_namelen = attr->namelen;
 308         /* fsid is left zero */
 309 }
 310
 311 static int fuse_statfs(struct dentry *dentry, struct kstatfs *buf)
 312 {
 313         struct super_block *sb = dentry->d_sb;
 314         struct fuse_conn *fc = get_fuse_conn_super(sb);
 315         struct fuse_req *req;
 316         struct fuse_statfs_out outarg;
 317         int err;
 318
 319         if (!fuse_allow_task(fc, current)) {
 320                 buf->f_type = FUSE_SUPER_MAGIC;
 321                 return 0;
 322         }
 323
 324         req = fuse_get_req(fc);
 325         if (IS_ERR(req))
 326                 return PTR_ERR(req);
 327
 328         memset(&outarg, 0, sizeof(outarg));
 329         req->in.numargs = 0;
 330         req->in.h.opcode = FUSE_STATFS;
 331         req->in.h.nodeid = get_node_id(dentry->d_inode);
 332         req->out.numargs = 1;
 333         req->out.args[0].size =
 334                 fc->minor < 4 ? FUSE_COMPAT_STATFS_SIZE : sizeof(outarg);
 335         req->out.args[0].value = &outarg;
 336         request_send(fc, req);
 337         err = req->out.h.error;
 338         if (!err)
 339                 convert_fuse_statfs(buf, &outarg.st);
 340         fuse_put_request(fc, req);
 341         return err;
 342 }
 343
 344 enum {
 345         OPT_FD,
 346         OPT_ROOTMODE,
 347         OPT_USER_ID,
 348         OPT_GROUP_ID,
 349         OPT_DEFAULT_PERMISSIONS,
 350         OPT_ALLOW_OTHER,
 351         OPT_MAX_READ,
 352         OPT_BLKSIZE,
 353         OPT_ERR
 354 };
 355
 356 static match_table_t tokens = {
 357         {OPT_FD,                        "fd=%u"},
 358         {OPT_ROOTMODE,                  "rootmode=%o"},
 359         {OPT_USER_ID,                   "user_id=%u"},
 360         {OPT_GROUP_ID,                  "group_id=%u"},
 361         {OPT_DEFAULT_PERMISSIONS,       "default_permissions"},
 362         {OPT_ALLOW_OTHER,               "allow_other"},
 363         {OPT_MAX_READ,                  "max_read=%u"},
 364         {OPT_BLKSIZE,                   "blksize=%u"},
 365         {OPT_ERR,                       NULL}
 366 };
 367
 368 static int parse_fuse_opt(char *opt, struct fuse_mount_data *d, int is_bdev)
 369 {
 370         char *p;
 371         memset(d, 0, sizeof(struct fuse_mount_data));
 372         d->max_read = ~0;
 373         d->blksize = FUSE_DEFAULT_BLKSIZE;
 374
 375         while ((p = strsep(&opt, ",")) != NULL) {
 376                 int token;
 377                 int value;
 378                 substring_t args[MAX_OPT_ARGS];
 379                 if (!*p)
 380                         continue;
 381
 382                 token = match_token(p, tokens, args);
 383                 switch (token) {
 384                 case OPT_FD:
 385                         if (match_int(&args[0], &value))
 386                                 return 0;
 387                         d->fd = value;
 388                         d->fd_present = 1;
 389                         break;
 390
 391                 case OPT_ROOTMODE:
 392                         if (match_octal(&args[0], &value))
 393                                 return 0;
 394                         if (!fuse_valid_type(value))
 395                                 return 0;
 396                         d->rootmode = value;
 397                         d->rootmode_present = 1;
 398                         break;
 399
 400                 case OPT_USER_ID:
 401                         if (match_int(&args[0], &value))
 402                                 return 0;
 403                         d->user_id = value;
 404                         d->user_id_present = 1;
 405                         break;
 406
 407                 case OPT_GROUP_ID:
 408                         if (match_int(&args[0], &value))
 409                                 return 0;
 410                         d->group_id = value;
 411                         d->group_id_present = 1;
 412                         break;
 413
 414                 case OPT_DEFAULT_PERMISSIONS:
 415                         d->flags |= FUSE_DEFAULT_PERMISSIONS;
 416                         break;
 417
 418                 case OPT_ALLOW_OTHER:
 419                         d->flags |= FUSE_ALLOW_OTHER;
 420                         break;
 421
 422                 case OPT_MAX_READ:
 423                         if (match_int(&args[0], &value))
 424                                 return 0;
 425                         d->max_read = value;
 426                         break;
 427
 428                 case OPT_BLKSIZE:
 429                         if (!is_bdev || match_int(&args[0], &value))
 430                                 return 0;
 431                         d->blksize = value;
 432                         break;
 433
 434                 default:
 435                         return 0;
 436                 }
 437         }
 438
 439         if (!d->fd_present || !d->rootmode_present ||
 440             !d->user_id_present || !d->group_id_present)
 441                 return 0;
 442
 443         return 1;
 444 }
 445
 446 static int fuse_show_options(struct seq_file *m, struct vfsmount *mnt)
 447 {
 448         struct fuse_conn *fc = get_fuse_conn_super(mnt->mnt_sb);
 449
 450         seq_printf(m, ",user_id=%u", fc->user_id);
 451         seq_printf(m, ",group_id=%u", fc->group_id);
 452         if (fc->flags & FUSE_DEFAULT_PERMISSIONS)
 453                 seq_puts(m, ",default_permissions");
 454         if (fc->flags & FUSE_ALLOW_OTHER)
 455                 seq_puts(m, ",allow_other");
 456         if (fc->max_read != ~0)
 457                 seq_printf(m, ",max_read=%u", fc->max_read);
 458         if (mnt->mnt_sb->s_bdev &&
 459             mnt->mnt_sb->s_blocksize != FUSE_DEFAULT_BLKSIZE)
 460                 seq_printf(m, ",blksize=%lu", mnt->mnt_sb->s_blocksize);
 461         return 0;
 462 }
 463
 464 static struct fuse_conn *new_conn(struct super_block *sb)
 465 {
 466         struct fuse_conn *fc;
 467         int err;
 468
 469         fc = kzalloc(sizeof(*fc), GFP_KERNEL);
 470         if (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                 atomic_set(&fc->num_waiting, 0);
 483                 fc->bdi.ra_pages = (VM_MAX_READAHEAD * 1024) / PAGE_CACHE_SIZE;
 484                 fc->bdi.unplug_io_fn = default_unplug_io_fn;
 485                 /* fuse does it's own writeback accounting */
 486                 fc->bdi.capabilities = BDI_CAP_NO_ACCT_WB;
 487                 fc->dev = sb->s_dev;
 488                 err = bdi_init(&fc->bdi);
 489                 if (err)
 490                         goto error_kfree;
 491                 err = bdi_register_dev(&fc->bdi, fc->dev);
 492                 if (err)
 493                         goto error_bdi_destroy;
 494                 /*
 495                  * For a single fuse filesystem use max 1% of dirty +
 496                  * writeback threshold.
 497                  *
 498                  * This gives about 1M of write buffer for memory maps on a
 499                  * machine with 1G and 10% dirty_ratio, which should be more
 500                  * than enough.
 501                  *
 502                  * Privileged users can raise it by writing to
 503                  *
 504                  *    /sys/class/bdi/<bdi>/max_ratio
 505                  */
 506                 bdi_set_max_ratio(&fc->bdi, 1);
 507                 fc->reqctr = 0;
 508                 fc->blocked = 1;
 509                 fc->attr_version = 1;
 510                 get_random_bytes(&fc->scramble_key, sizeof(fc->scramble_key));
 511         }
 512         return fc;
 513
 514 error_bdi_destroy:
 515         bdi_destroy(&fc->bdi);
 516 error_kfree:
 517         mutex_destroy(&fc->inst_mutex);
 518         kfree(fc);
 519         return NULL;
 520 }
 521
 522 void fuse_conn_put(struct fuse_conn *fc)
 523 {
 524         if (atomic_dec_and_test(&fc->count)) {
 525                 if (fc->destroy_req)
 526                         fuse_request_free(fc->destroy_req);
 527                 mutex_destroy(&fc->inst_mutex);
 528                 bdi_destroy(&fc->bdi);
 529                 kfree(fc);
 530         }
 531 }
 532
 533 struct fuse_conn *fuse_conn_get(struct fuse_conn *fc)
 534 {
 535         atomic_inc(&fc->count);
 536         return fc;
 537 }
 538
 539 static struct inode *get_root_inode(struct super_block *sb, unsigned mode)
 540 {
 541         struct fuse_attr attr;
 542         memset(&attr, 0, sizeof(attr));
 543
 544         attr.mode = mode;
 545         attr.ino = FUSE_ROOT_ID;
 546         attr.nlink = 1;
 547         return fuse_iget(sb, 1, 0, &attr, 0, 0);
 548 }
 549
 550 static const struct super_operations fuse_super_operations = {
 551         .alloc_inode    = fuse_alloc_inode,
 552         .destroy_inode  = fuse_destroy_inode,
 553         .clear_inode    = fuse_clear_inode,
 554         .drop_inode     = generic_delete_inode,
 555         .remount_fs     = fuse_remount_fs,
 556         .put_super      = fuse_put_super,
 557         .umount_begin   = fuse_umount_begin,
 558         .statfs         = fuse_statfs,
 559         .show_options   = fuse_show_options,
 560 };
 561
 562 static void process_init_reply(struct fuse_conn *fc, struct fuse_req *req)
 563 {
 564         struct fuse_init_out *arg = &req->misc.init_out;
 565
 566         if (req->out.h.error || arg->major != FUSE_KERNEL_VERSION)
 567                 fc->conn_error = 1;
 568         else {
 569                 unsigned long ra_pages;
 570
 571                 if (arg->minor >= 6) {
 572                         ra_pages = arg->max_readahead / PAGE_CACHE_SIZE;
 573                         if (arg->flags & FUSE_ASYNC_READ)
 574                                 fc->async_read = 1;
 575                         if (!(arg->flags & FUSE_POSIX_LOCKS))
 576                                 fc->no_lock = 1;
 577                         if (arg->flags & FUSE_ATOMIC_O_TRUNC)
 578                                 fc->atomic_o_trunc = 1;
 579                         if (arg->flags & FUSE_BIG_WRITES)
 580                                 fc->big_writes = 1;
 581                 } else {
 582                         ra_pages = fc->max_read / PAGE_CACHE_SIZE;
 583                         fc->no_lock = 1;
 584                 }
 585
 586                 fc->bdi.ra_pages = min(fc->bdi.ra_pages, ra_pages);
 587                 fc->minor = arg->minor;
 588                 fc->max_write = arg->minor < 5 ? 4096 : arg->max_write;
 589                 fc->max_write = min_t(unsigned, 4096, fc->max_write);
 590                 fc->conn_init = 1;
 591         }
 592         fuse_put_request(fc, req);
 593         fc->blocked = 0;
 594         wake_up_all(&fc->blocked_waitq);
 595 }
 596
 597 static void fuse_send_init(struct fuse_conn *fc, struct fuse_req *req)
 598 {
 599         struct fuse_init_in *arg = &req->misc.init_in;
 600
 601         arg->major = FUSE_KERNEL_VERSION;
 602         arg->minor = FUSE_KERNEL_MINOR_VERSION;
 603         arg->max_readahead = fc->bdi.ra_pages * PAGE_CACHE_SIZE;
 604         arg->flags |= FUSE_ASYNC_READ | FUSE_POSIX_LOCKS | FUSE_ATOMIC_O_TRUNC |
 605                 FUSE_BIG_WRITES;
 606         req->in.h.opcode = FUSE_INIT;
 607         req->in.numargs = 1;
 608         req->in.args[0].size = sizeof(*arg);
 609         req->in.args[0].value = arg;
 610         req->out.numargs = 1;
 611         /* Variable length arguement used for backward compatibility
 612            with interface version < 7.5.  Rest of init_out is zeroed
 613            by do_get_request(), so a short reply is not a problem */
 614         req->out.argvar = 1;
 615         req->out.args[0].size = sizeof(struct fuse_init_out);
 616         req->out.args[0].value = &req->misc.init_out;
 617         req->end = process_init_reply;
 618         request_send_background(fc, req);
 619 }
 620
 621 static int fuse_fill_super(struct super_block *sb, void *data, int silent)
 622 {
 623         struct fuse_conn *fc;
 624         struct inode *root;
 625         struct fuse_mount_data d;
 626         struct file *file;
 627         struct dentry *root_dentry;
 628         struct fuse_req *init_req;
 629         int err;
 630         int is_bdev = sb->s_bdev != NULL;
 631
 632         if (sb->s_flags & MS_MANDLOCK)
 633                 return -EINVAL;
 634
 635         if (!parse_fuse_opt((char *) data, &d, is_bdev))
 636                 return -EINVAL;
 637
 638         if (is_bdev) {
 639 #ifdef CONFIG_BLOCK
 640                 if (!sb_set_blocksize(sb, d.blksize))
 641                         return -EINVAL;
 642 #endif
 643         } else {
 644                 sb->s_blocksize = PAGE_CACHE_SIZE;
 645                 sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
 646         }
 647         sb->s_magic = FUSE_SUPER_MAGIC;
 648         sb->s_op = &fuse_super_operations;
 649         sb->s_maxbytes = MAX_LFS_FILESIZE;
 650
 651         file = fget(d.fd);
 652         if (!file)
 653                 return -EINVAL;
 654
 655         if (file->f_op != &fuse_dev_operations)
 656                 return -EINVAL;
 657
 658         fc = new_conn(sb);
 659         if (!fc)
 660                 return -ENOMEM;
 661
 662         fc->flags = d.flags;
 663         fc->user_id = d.user_id;
 664         fc->group_id = d.group_id;
 665         fc->max_read = min_t(unsigned, 4096, d.max_read);
 666
 667         /* Used by get_root_inode() */
 668         sb->s_fs_info = fc;
 669
 670         err = -ENOMEM;
 671         root = get_root_inode(sb, d.rootmode);
 672         if (!root)
 673                 goto err;
 674
 675         root_dentry = d_alloc_root(root);
 676         if (!root_dentry) {
 677                 iput(root);
 678                 goto err;
 679         }
 680
 681         init_req = fuse_request_alloc();
 682         if (!init_req)
 683                 goto err_put_root;
 684
 685         if (is_bdev) {
 686                 fc->destroy_req = fuse_request_alloc();
 687                 if (!fc->destroy_req)
 688                         goto err_put_root;
 689         }
 690
 691         mutex_lock(&fuse_mutex);
 692         err = -EINVAL;
 693         if (file->private_data)
 694                 goto err_unlock;
 695
 696         err = fuse_ctl_add_conn(fc);
 697         if (err)
 698                 goto err_unlock;
 699
 700         list_add_tail(&fc->entry, &fuse_conn_list);
 701         sb->s_root = root_dentry;
 702         fc->connected = 1;
 703         file->private_data = fuse_conn_get(fc);
 704         mutex_unlock(&fuse_mutex);
 705         /*
 706          * atomic_dec_and_test() in fput() provides the necessary
 707          * memory barrier for file->private_data to be visible on all
 708          * CPUs after this
 709          */
 710         fput(file);
 711
 712         fuse_send_init(fc, init_req);
 713
 714         return 0;
 715
 716  err_unlock:
 717         mutex_unlock(&fuse_mutex);
 718         fuse_request_free(init_req);
 719  err_put_root:
 720         dput(root_dentry);
 721  err:
 722         fput(file);
 723         fuse_conn_put(fc);
 724         return err;
 725 }
 726
 727 static int fuse_get_sb(struct file_system_type *fs_type,
 728                        int flags, const char *dev_name,
 729                        void *raw_data, struct vfsmount *mnt)
 730 {
 731         return get_sb_nodev(fs_type, flags, raw_data, fuse_fill_super, mnt);
 732 }
 733
 734 static struct file_system_type fuse_fs_type = {
 735         .owner          = THIS_MODULE,
 736         .name           = "fuse",
 737         .fs_flags       = FS_HAS_SUBTYPE,
 738         .get_sb         = fuse_get_sb,
 739         .kill_sb        = kill_anon_super,
 740 };
 741
 742 #ifdef CONFIG_BLOCK
 743 static int fuse_get_sb_blk(struct file_system_type *fs_type,
 744                            int flags, const char *dev_name,
 745                            void *raw_data, struct vfsmount *mnt)
 746 {
 747         return get_sb_bdev(fs_type, flags, dev_name, raw_data, fuse_fill_super,
 748                            mnt);
 749 }
 750
 751 static struct file_system_type fuseblk_fs_type = {
 752         .owner          = THIS_MODULE,
 753         .name           = "fuseblk",
 754         .get_sb         = fuse_get_sb_blk,
 755         .kill_sb        = kill_block_super,
 756         .fs_flags       = FS_REQUIRES_DEV | FS_HAS_SUBTYPE,
 757 };
 758
 759 static inline int register_fuseblk(void)
 760 {
 761         return register_filesystem(&fuseblk_fs_type);
 762 }
 763
 764 static inline void unregister_fuseblk(void)
 765 {
 766         unregister_filesystem(&fuseblk_fs_type);
 767 }
 768 #else
 769 static inline int register_fuseblk(void)
 770 {
 771         return 0;
 772 }
 773
 774 static inline void unregister_fuseblk(void)
 775 {
 776 }
 777 #endif
 778
 779 static void fuse_inode_init_once(struct kmem_cache *cachep, void *foo)
 780 {
 781         struct inode * inode = foo;
 782
 783         inode_init_once(inode);
 784 }
 785
 786 static int __init fuse_fs_init(void)
 787 {
 788         int err;
 789
 790         err = register_filesystem(&fuse_fs_type);
 791         if (err)
 792                 goto out;
 793
 794         err = register_fuseblk();
 795         if (err)
 796                 goto out_unreg;
 797
 798         fuse_inode_cachep = kmem_cache_create("fuse_inode",
 799                                               sizeof(struct fuse_inode),
 800                                               0, SLAB_HWCACHE_ALIGN,
 801                                               fuse_inode_init_once);
 802         err = -ENOMEM;
 803         if (!fuse_inode_cachep)
 804                 goto out_unreg2;
 805
 806         return 0;
 807
 808  out_unreg2:
 809         unregister_fuseblk();
 810  out_unreg:
 811         unregister_filesystem(&fuse_fs_type);
 812  out:
 813         return err;
 814 }
 815
 816 static void fuse_fs_cleanup(void)
 817 {
 818         unregister_filesystem(&fuse_fs_type);
 819         unregister_fuseblk();
 820         kmem_cache_destroy(fuse_inode_cachep);
 821 }
 822
 823 static struct kobject *fuse_kobj;
 824 static struct kobject *connections_kobj;
 825
 826 static int fuse_sysfs_init(void)
 827 {
 828         int err;
 829
 830         fuse_kobj = kobject_create_and_add("fuse", fs_kobj);
 831         if (!fuse_kobj) {
 832                 err = -ENOMEM;
 833                 goto out_err;
 834         }
 835
 836         connections_kobj = kobject_create_and_add("connections", fuse_kobj);
 837         if (!connections_kobj) {
 838                 err = -ENOMEM;
 839                 goto out_fuse_unregister;
 840         }
 841
 842         return 0;
 843
 844  out_fuse_unregister:
 845         kobject_put(fuse_kobj);
 846  out_err:
 847         return err;
 848 }
 849
 850 static void fuse_sysfs_cleanup(void)
 851 {
 852         kobject_put(connections_kobj);
 853         kobject_put(fuse_kobj);
 854 }
 855
 856 static int __init fuse_init(void)
 857 {
 858         int res;
 859
 860         printk("fuse init (API version %i.%i)\n",
 861                FUSE_KERNEL_VERSION, FUSE_KERNEL_MINOR_VERSION);
 862
 863         INIT_LIST_HEAD(&fuse_conn_list);
 864         res = fuse_fs_init();
 865         if (res)
 866                 goto err;
 867
 868         res = fuse_dev_init();
 869         if (res)
 870                 goto err_fs_cleanup;
 871
 872         res = fuse_sysfs_init();
 873         if (res)
 874                 goto err_dev_cleanup;
 875
 876         res = fuse_ctl_init();
 877         if (res)
 878                 goto err_sysfs_cleanup;
 879
 880         return 0;
 881
 882  err_sysfs_cleanup:
 883         fuse_sysfs_cleanup();
 884  err_dev_cleanup:
 885         fuse_dev_cleanup();
 886  err_fs_cleanup:
 887         fuse_fs_cleanup();
 888  err:
 889         return res;
 890 }
 891
 892 static void __exit fuse_exit(void)
 893 {
 894         printk(KERN_DEBUG "fuse exit\n");
 895
 896         fuse_ctl_cleanup();
 897         fuse_sysfs_cleanup();
 898         fuse_fs_cleanup();
 899         fuse_dev_cleanup();
 900 }
 901
 902 module_init(fuse_init);
 903 module_exit(fuse_exit);