net/sunrpc/rpc_pipe.c

   1 /*
   2  * net/sunrpc/rpc_pipe.c
   3  *
   4  * Userland/kernel interface for rpcauth_gss.
   5  * Code shamelessly plagiarized from fs/nfsd/nfsctl.c
   6  * and fs/driverfs/inode.c
   7  *
   8  * Copyright (c) 2002, Trond Myklebust <trond.myklebust@fys.uio.no>
   9  *
  10  */
  11 #include <linux/config.h>
  12 #include <linux/module.h>
  13 #include <linux/slab.h>
  14 #include <linux/string.h>
  15 #include <linux/pagemap.h>
  16 #include <linux/mount.h>
  17 #include <linux/namei.h>
  18 #include <linux/dnotify.h>
  19 #include <linux/kernel.h>
  20
  21 #include <asm/ioctls.h>
  22 #include <linux/fs.h>
  23 #include <linux/poll.h>
  24 #include <linux/wait.h>
  25 #include <linux/seq_file.h>
  26
  27 #include <linux/sunrpc/clnt.h>
  28 #include <linux/workqueue.h>
  29 #include <linux/sunrpc/rpc_pipe_fs.h>
  30
  31 static struct vfsmount *rpc_mount;
  32 static int rpc_mount_count;
  33
  34 static struct file_system_type rpc_pipe_fs_type;
  35
  36
  37 static kmem_cache_t *rpc_inode_cachep;
  38
  39 #define RPC_UPCALL_TIMEOUT (30*HZ)
  40
  41 static void
  42 __rpc_purge_upcall(struct inode *inode, int err)
  43 {
  44         struct rpc_inode *rpci = RPC_I(inode);
  45         struct rpc_pipe_msg *msg;
  46
  47         while (!list_empty(&rpci->pipe)) {
  48                 msg = list_entry(rpci->pipe.next, struct rpc_pipe_msg, list);
  49                 list_del_init(&msg->list);
  50                 msg->errno = err;
  51                 rpci->ops->destroy_msg(msg);
  52         }
  53         while (!list_empty(&rpci->in_upcall)) {
  54                 msg = list_entry(rpci->pipe.next, struct rpc_pipe_msg, list);
  55                 list_del_init(&msg->list);
  56                 msg->errno = err;
  57                 rpci->ops->destroy_msg(msg);
  58         }
  59         rpci->pipelen = 0;
  60         wake_up(&rpci->waitq);
  61 }
  62
  63 static void
  64 rpc_timeout_upcall_queue(void *data)
  65 {
  66         struct rpc_inode *rpci = (struct rpc_inode *)data;
  67         struct inode *inode = &rpci->vfs_inode;
  68
  69         down(&inode->i_sem);
  70         if (rpci->nreaders == 0 && !list_empty(&rpci->pipe))
  71                 __rpc_purge_upcall(inode, -ETIMEDOUT);
  72         up(&inode->i_sem);
  73 }
  74
  75 int
  76 rpc_queue_upcall(struct inode *inode, struct rpc_pipe_msg *msg)
  77 {
  78         struct rpc_inode *rpci = RPC_I(inode);
  79         int res = 0;
  80
  81         down(&inode->i_sem);
  82         if (rpci->nreaders) {
  83                 list_add_tail(&msg->list, &rpci->pipe);
  84                 rpci->pipelen += msg->len;
  85         } else if (rpci->flags & RPC_PIPE_WAIT_FOR_OPEN) {
  86                 if (list_empty(&rpci->pipe))
  87                         schedule_delayed_work(&rpci->queue_timeout,
  88                                         RPC_UPCALL_TIMEOUT);
  89                 list_add_tail(&msg->list, &rpci->pipe);
  90                 rpci->pipelen += msg->len;
  91         } else
  92                 res = -EPIPE;
  93         up(&inode->i_sem);
  94         wake_up(&rpci->waitq);
  95         return res;
  96 }
  97
  98 static void
  99 rpc_close_pipes(struct inode *inode)
 100 {
 101         struct rpc_inode *rpci = RPC_I(inode);
 102
 103         cancel_delayed_work(&rpci->queue_timeout);
 104         flush_scheduled_work();
 105         down(&inode->i_sem);
 106         if (rpci->ops != NULL) {
 107                 rpci->nreaders = 0;
 108                 __rpc_purge_upcall(inode, -EPIPE);
 109                 rpci->nwriters = 0;
 110                 if (rpci->ops->release_pipe)
 111                         rpci->ops->release_pipe(inode);
 112                 rpci->ops = NULL;
 113         }
 114         up(&inode->i_sem);
 115 }
 116
 117 static inline void
 118 rpc_inode_setowner(struct inode *inode, void *private)
 119 {
 120         RPC_I(inode)->private = private;
 121 }
 122
 123 static struct inode *
 124 rpc_alloc_inode(struct super_block *sb)
 125 {
 126         struct rpc_inode *rpci;
 127         rpci = (struct rpc_inode *)kmem_cache_alloc(rpc_inode_cachep, SLAB_KERNEL);
 128         if (!rpci)
 129                 return NULL;
 130         return &rpci->vfs_inode;
 131 }
 132
 133 static void
 134 rpc_destroy_inode(struct inode *inode)
 135 {
 136         kmem_cache_free(rpc_inode_cachep, RPC_I(inode));
 137 }
 138
 139 static int
 140 rpc_pipe_open(struct inode *inode, struct file *filp)
 141 {
 142         struct rpc_inode *rpci = RPC_I(inode);
 143         int res = -ENXIO;
 144
 145         down(&inode->i_sem);
 146         if (rpci->ops != NULL) {
 147                 if (filp->f_mode & FMODE_READ)
 148                         rpci->nreaders ++;
 149                 if (filp->f_mode & FMODE_WRITE)
 150                         rpci->nwriters ++;
 151                 res = 0;
 152         }
 153         up(&inode->i_sem);
 154         return res;
 155 }
 156
 157 static int
 158 rpc_pipe_release(struct inode *inode, struct file *filp)
 159 {
 160         struct rpc_inode *rpci = RPC_I(filp->f_dentry->d_inode);
 161         struct rpc_pipe_msg *msg;
 162
 163         down(&inode->i_sem);
 164         if (rpci->ops == NULL)
 165                 goto out;
 166         msg = (struct rpc_pipe_msg *)filp->private_data;
 167         if (msg != NULL) {
 168                 msg->errno = -EPIPE;
 169                 list_del_init(&msg->list);
 170                 rpci->ops->destroy_msg(msg);
 171         }
 172         if (filp->f_mode & FMODE_WRITE)
 173                 rpci->nwriters --;
 174         if (filp->f_mode & FMODE_READ)
 175                 rpci->nreaders --;
 176         if (!rpci->nreaders)
 177                 __rpc_purge_upcall(inode, -EPIPE);
 178         if (rpci->ops->release_pipe)
 179                 rpci->ops->release_pipe(inode);
 180 out:
 181         up(&inode->i_sem);
 182         return 0;
 183 }
 184
 185 static ssize_t
 186 rpc_pipe_read(struct file *filp, char __user *buf, size_t len, loff_t *offset)
 187 {
 188         struct inode *inode = filp->f_dentry->d_inode;
 189         struct rpc_inode *rpci = RPC_I(inode);
 190         struct rpc_pipe_msg *msg;
 191         int res = 0;
 192
 193         down(&inode->i_sem);
 194         if (rpci->ops == NULL) {
 195                 res = -EPIPE;
 196                 goto out_unlock;
 197         }
 198         msg = filp->private_data;
 199         if (msg == NULL) {
 200                 if (!list_empty(&rpci->pipe)) {
 201                         msg = list_entry(rpci->pipe.next,
 202                                         struct rpc_pipe_msg,
 203                                         list);
 204                         list_move(&msg->list, &rpci->in_upcall);
 205                         rpci->pipelen -= msg->len;
 206                         filp->private_data = msg;
 207                         msg->copied = 0;
 208                 }
 209                 if (msg == NULL)
 210                         goto out_unlock;
 211         }
 212         /* NOTE: it is up to the callback to update msg->copied */
 213         res = rpci->ops->upcall(filp, msg, buf, len);
 214         if (res < 0 || msg->len == msg->copied) {
 215                 filp->private_data = NULL;
 216                 list_del_init(&msg->list);
 217                 rpci->ops->destroy_msg(msg);
 218         }
 219 out_unlock:
 220         up(&inode->i_sem);
 221         return res;
 222 }
 223
 224 static ssize_t
 225 rpc_pipe_write(struct file *filp, const char __user *buf, size_t len, loff_t *offset)
 226 {
 227         struct inode *inode = filp->f_dentry->d_inode;
 228         struct rpc_inode *rpci = RPC_I(inode);
 229         int res;
 230
 231         down(&inode->i_sem);
 232         res = -EPIPE;
 233         if (rpci->ops != NULL)
 234                 res = rpci->ops->downcall(filp, buf, len);
 235         up(&inode->i_sem);
 236         return res;
 237 }
 238
 239 static unsigned int
 240 rpc_pipe_poll(struct file *filp, struct poll_table_struct *wait)
 241 {
 242         struct rpc_inode *rpci;
 243         unsigned int mask = 0;
 244
 245         rpci = RPC_I(filp->f_dentry->d_inode);
 246         poll_wait(filp, &rpci->waitq, wait);
 247
 248         mask = POLLOUT | POLLWRNORM;
 249         if (rpci->ops == NULL)
 250                 mask |= POLLERR | POLLHUP;
 251         if (!list_empty(&rpci->pipe))
 252                 mask |= POLLIN | POLLRDNORM;
 253         return mask;
 254 }
 255
 256 static int
 257 rpc_pipe_ioctl(struct inode *ino, struct file *filp,
 258                 unsigned int cmd, unsigned long arg)
 259 {
 260         struct rpc_inode *rpci = RPC_I(filp->f_dentry->d_inode);
 261         int len;
 262
 263         switch (cmd) {
 264         case FIONREAD:
 265                 if (rpci->ops == NULL)
 266                         return -EPIPE;
 267                 len = rpci->pipelen;
 268                 if (filp->private_data) {
 269                         struct rpc_pipe_msg *msg;
 270                         msg = (struct rpc_pipe_msg *)filp->private_data;
 271                         len += msg->len - msg->copied;
 272                 }
 273                 return put_user(len, (int __user *)arg);
 274         default:
 275                 return -EINVAL;
 276         }
 277 }
 278
 279 struct inode_operations rpc_pipe_iops = {
 280         .lookup         = simple_lookup,
 281 };
 282
 283
 284 struct file_operations rpc_pipe_fops = {
 285         .owner          = THIS_MODULE,
 286         .llseek         = no_llseek,
 287         .read           = rpc_pipe_read,
 288         .write          = rpc_pipe_write,
 289         .poll           = rpc_pipe_poll,
 290         .ioctl          = rpc_pipe_ioctl,
 291         .open           = rpc_pipe_open,
 292         .release        = rpc_pipe_release,
 293 };
 294
 295 static int
 296 rpc_show_info(struct seq_file *m, void *v)
 297 {
 298         struct rpc_clnt *clnt = m->private;
 299
 300         seq_printf(m, "RPC server: %s\n", clnt->cl_server);
 301         seq_printf(m, "service: %s (%d) version %d\n", clnt->cl_protname,
 302                         clnt->cl_prog, clnt->cl_vers);
 303         seq_printf(m, "address: %u.%u.%u.%u\n",
 304                         NIPQUAD(clnt->cl_xprt->addr.sin_addr.s_addr));
 305         seq_printf(m, "protocol: %s\n",
 306                         clnt->cl_xprt->prot == IPPROTO_UDP ? "udp" : "tcp");
 307         return 0;
 308 }
 309
 310 static int
 311 rpc_info_open(struct inode *inode, struct file *file)
 312 {
 313         struct rpc_clnt *clnt;
 314         int ret = single_open(file, rpc_show_info, NULL);
 315
 316         if (!ret) {
 317                 struct seq_file *m = file->private_data;
 318                 down(&inode->i_sem);
 319                 clnt = RPC_I(inode)->private;
 320                 if (clnt) {
 321                         atomic_inc(&clnt->cl_users);
 322                         m->private = clnt;
 323                 } else {
 324                         single_release(inode, file);
 325                         ret = -EINVAL;
 326                 }
 327                 up(&inode->i_sem);
 328         }
 329         return ret;
 330 }
 331
 332 static int
 333 rpc_info_release(struct inode *inode, struct file *file)
 334 {
 335         struct seq_file *m = file->private_data;
 336         struct rpc_clnt *clnt = (struct rpc_clnt *)m->private;
 337
 338         if (clnt)
 339                 rpc_release_client(clnt);
 340         return single_release(inode, file);
 341 }
 342
 343 static struct file_operations rpc_info_operations = {
 344         .owner          = THIS_MODULE,
 345         .open           = rpc_info_open,
 346         .read           = seq_read,
 347         .llseek         = seq_lseek,
 348         .release        = rpc_info_release,
 349 };
 350
 351
 352 /*
 353  * We have a single directory with 1 node in it.
 354  */
 355 enum {
 356         RPCAUTH_Root = 1,
 357         RPCAUTH_lockd,
 358         RPCAUTH_mount,
 359         RPCAUTH_nfs,
 360         RPCAUTH_portmap,
 361         RPCAUTH_statd,
 362         RPCAUTH_RootEOF
 363 };
 364
 365 /*
 366  * Description of fs contents.
 367  */
 368 struct rpc_filelist {
 369         char *name;
 370         struct file_operations *i_fop;
 371         int mode;
 372 };
 373
 374 static struct rpc_filelist files[] = {
 375         [RPCAUTH_lockd] = {
 376                 .name = "lockd",
 377                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
 378         },
 379         [RPCAUTH_mount] = {
 380                 .name = "mount",
 381                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
 382         },
 383         [RPCAUTH_nfs] = {
 384                 .name = "nfs",
 385                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
 386         },
 387         [RPCAUTH_portmap] = {
 388                 .name = "portmap",
 389                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
 390         },
 391         [RPCAUTH_statd] = {
 392                 .name = "statd",
 393                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
 394         },
 395 };
 396
 397 enum {
 398         RPCAUTH_info = 2,
 399         RPCAUTH_EOF
 400 };
 401
 402 static struct rpc_filelist authfiles[] = {
 403         [RPCAUTH_info] = {
 404                 .name = "info",
 405                 .i_fop = &rpc_info_operations,
 406                 .mode = S_IFREG | S_IRUSR,
 407         },
 408 };
 409
 410 static int
 411 rpc_get_mount(void)
 412 {
 413         return simple_pin_fs("rpc_pipefs", &rpc_mount, &rpc_mount_count);
 414 }
 415
 416 static void
 417 rpc_put_mount(void)
 418 {
 419         simple_release_fs(&rpc_mount, &rpc_mount_count);
 420 }
 421
 422 static int
 423 rpc_lookup_parent(char *path, struct nameidata *nd)
 424 {
 425         if (path[0] == '\0')
 426                 return -ENOENT;
 427         if (rpc_get_mount()) {
 428                 printk(KERN_WARNING "%s: %s failed to mount "
 429                                "pseudofilesystem \n", __FILE__, __FUNCTION__);
 430                 return -ENODEV;
 431         }
 432         nd->mnt = mntget(rpc_mount);
 433         nd->dentry = dget(rpc_mount->mnt_root);
 434         nd->last_type = LAST_ROOT;
 435         nd->flags = LOOKUP_PARENT;
 436         nd->depth = 0;
 437
 438         if (path_walk(path, nd)) {
 439                 printk(KERN_WARNING "%s: %s failed to find path %s\n",
 440                                 __FILE__, __FUNCTION__, path);
 441                 rpc_put_mount();
 442                 return -ENOENT;
 443         }
 444         return 0;
 445 }
 446
 447 static void
 448 rpc_release_path(struct nameidata *nd)
 449 {
 450         path_release(nd);
 451         rpc_put_mount();
 452 }
 453
 454 static struct inode *
 455 rpc_get_inode(struct super_block *sb, int mode)
 456 {
 457         struct inode *inode = new_inode(sb);
 458         if (!inode)
 459                 return NULL;
 460         inode->i_mode = mode;
 461         inode->i_uid = inode->i_gid = 0;
 462         inode->i_blksize = PAGE_CACHE_SIZE;
 463         inode->i_blocks = 0;
 464         inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
 465         switch(mode & S_IFMT) {
 466                 case S_IFDIR:
 467                         inode->i_fop = &simple_dir_operations;
 468                         inode->i_op = &simple_dir_inode_operations;
 469                         inode->i_nlink++;
 470                 default:
 471                         break;
 472         }
 473         return inode;
 474 }
 475
 476 /*
 477  * FIXME: This probably has races.
 478  */
 479 static void
 480 rpc_depopulate(struct dentry *parent)
 481 {
 482         struct inode *dir = parent->d_inode;
 483         struct list_head *pos, *next;
 484         struct dentry *dentry, *dvec[10];
 485         int n = 0;
 486
 487         down(&dir->i_sem);
 488 repeat:
 489         spin_lock(&dcache_lock);
 490         list_for_each_safe(pos, next, &parent->d_subdirs) {
 491                 dentry = list_entry(pos, struct dentry, d_child);
 492                 spin_lock(&dentry->d_lock);
 493                 if (!d_unhashed(dentry)) {
 494                         dget_locked(dentry);
 495                         __d_drop(dentry);
 496                         spin_unlock(&dentry->d_lock);
 497                         dvec[n++] = dentry;
 498                         if (n == ARRAY_SIZE(dvec))
 499                                 break;
 500                 } else
 501                         spin_unlock(&dentry->d_lock);
 502         }
 503         spin_unlock(&dcache_lock);
 504         if (n) {
 505                 do {
 506                         dentry = dvec[--n];
 507                         if (dentry->d_inode) {
 508                                 rpc_close_pipes(dentry->d_inode);
 509                                 rpc_inode_setowner(dentry->d_inode, NULL);
 510                                 simple_unlink(dir, dentry);
 511                         }
 512                         dput(dentry);
 513                 } while (n);
 514                 goto repeat;
 515         }
 516         up(&dir->i_sem);
 517 }
 518
 519 static int
 520 rpc_populate(struct dentry *parent,
 521                 struct rpc_filelist *files,
 522                 int start, int eof)
 523 {
 524         struct inode *inode, *dir = parent->d_inode;
 525         void *private = RPC_I(dir)->private;
 526         struct dentry *dentry;
 527         int mode, i;
 528
 529         down(&dir->i_sem);
 530         for (i = start; i < eof; i++) {
 531                 dentry = d_alloc_name(parent, files[i].name);
 532                 if (!dentry)
 533                         goto out_bad;
 534                 mode = files[i].mode;
 535                 inode = rpc_get_inode(dir->i_sb, mode);
 536                 if (!inode) {
 537                         dput(dentry);
 538                         goto out_bad;
 539                 }
 540                 inode->i_ino = i;
 541                 if (files[i].i_fop)
 542                         inode->i_fop = files[i].i_fop;
 543                 if (private)
 544                         rpc_inode_setowner(inode, private);
 545                 if (S_ISDIR(mode))
 546                         dir->i_nlink++;
 547                 d_add(dentry, inode);
 548         }
 549         up(&dir->i_sem);
 550         return 0;
 551 out_bad:
 552         up(&dir->i_sem);
 553         printk(KERN_WARNING "%s: %s failed to populate directory %s\n",
 554                         __FILE__, __FUNCTION__, parent->d_name.name);
 555         return -ENOMEM;
 556 }
 557
 558 static int
 559 __rpc_mkdir(struct inode *dir, struct dentry *dentry)
 560 {
 561         struct inode *inode;
 562
 563         inode = rpc_get_inode(dir->i_sb, S_IFDIR | S_IRUSR | S_IXUSR);
 564         if (!inode)
 565                 goto out_err;
 566         inode->i_ino = iunique(dir->i_sb, 100);
 567         d_instantiate(dentry, inode);
 568         dir->i_nlink++;
 569         inode_dir_notify(dir, DN_CREATE);
 570         rpc_get_mount();
 571         return 0;
 572 out_err:
 573         printk(KERN_WARNING "%s: %s failed to allocate inode for dentry %s\n",
 574                         __FILE__, __FUNCTION__, dentry->d_name.name);
 575         return -ENOMEM;
 576 }
 577
 578 static int
 579 __rpc_rmdir(struct inode *dir, struct dentry *dentry)
 580 {
 581         int error;
 582
 583         shrink_dcache_parent(dentry);
 584         if (dentry->d_inode) {
 585                 rpc_close_pipes(dentry->d_inode);
 586                 rpc_inode_setowner(dentry->d_inode, NULL);
 587         }
 588         if ((error = simple_rmdir(dir, dentry)) != 0)
 589                 return error;
 590         if (!error) {
 591                 inode_dir_notify(dir, DN_DELETE);
 592                 d_drop(dentry);
 593                 rpc_put_mount();
 594         }
 595         return 0;
 596 }
 597
 598 struct dentry *
 599 rpc_lookup_negative(char *path, struct nameidata *nd)
 600 {
 601         struct dentry *dentry;
 602         struct inode *dir;
 603         int error;
 604
 605         if ((error = rpc_lookup_parent(path, nd)) != 0)
 606                 return ERR_PTR(error);
 607         dir = nd->dentry->d_inode;
 608         down(&dir->i_sem);
 609         dentry = lookup_hash(&nd->last, nd->dentry);
 610         if (IS_ERR(dentry))
 611                 goto out_err;
 612         if (dentry->d_inode) {
 613                 dput(dentry);
 614                 dentry = ERR_PTR(-EEXIST);
 615                 goto out_err;
 616         }
 617         return dentry;
 618 out_err:
 619         up(&dir->i_sem);
 620         rpc_release_path(nd);
 621         return dentry;
 622 }
 623
 624
 625 struct dentry *
 626 rpc_mkdir(char *path, struct rpc_clnt *rpc_client)
 627 {
 628         struct nameidata nd;
 629         struct dentry *dentry;
 630         struct inode *dir;
 631         int error;
 632
 633         dentry = rpc_lookup_negative(path, &nd);
 634         if (IS_ERR(dentry))
 635                 return dentry;
 636         dir = nd.dentry->d_inode;
 637         if ((error = __rpc_mkdir(dir, dentry)) != 0)
 638                 goto err_dput;
 639         RPC_I(dentry->d_inode)->private = rpc_client;
 640         error = rpc_populate(dentry, authfiles,
 641                         RPCAUTH_info, RPCAUTH_EOF);
 642         if (error)
 643                 goto err_depopulate;
 644 out:
 645         up(&dir->i_sem);
 646         rpc_release_path(&nd);
 647         return dentry;
 648 err_depopulate:
 649         rpc_depopulate(dentry);
 650         __rpc_rmdir(dir, dentry);
 651 err_dput:
 652         dput(dentry);
 653         printk(KERN_WARNING "%s: %s() failed to create directory %s (errno = %d)\n",
 654                         __FILE__, __FUNCTION__, path, error);
 655         dentry = ERR_PTR(error);
 656         goto out;
 657 }
 658
 659 int
 660 rpc_rmdir(char *path)
 661 {
 662         struct nameidata nd;
 663         struct dentry *dentry;
 664         struct inode *dir;
 665         int error;
 666
 667         if ((error = rpc_lookup_parent(path, &nd)) != 0)
 668                 return error;
 669         dir = nd.dentry->d_inode;
 670         down(&dir->i_sem);
 671         dentry = lookup_hash(&nd.last, nd.dentry);
 672         if (IS_ERR(dentry)) {
 673                 error = PTR_ERR(dentry);
 674                 goto out_release;
 675         }
 676         rpc_depopulate(dentry);
 677         error = __rpc_rmdir(dir, dentry);
 678         dput(dentry);
 679 out_release:
 680         up(&dir->i_sem);
 681         rpc_release_path(&nd);
 682         return error;
 683 }
 684
 685 struct dentry *
 686 rpc_mkpipe(char *path, void *private, struct rpc_pipe_ops *ops, int flags)
 687 {
 688         struct nameidata nd;
 689         struct dentry *dentry;
 690         struct inode *dir, *inode;
 691         struct rpc_inode *rpci;
 692
 693         dentry = rpc_lookup_negative(path, &nd);
 694         if (IS_ERR(dentry))
 695                 return dentry;
 696         dir = nd.dentry->d_inode;
 697         inode = rpc_get_inode(dir->i_sb, S_IFSOCK | S_IRUSR | S_IWUSR);
 698         if (!inode)
 699                 goto err_dput;
 700         inode->i_ino = iunique(dir->i_sb, 100);
 701         inode->i_fop = &rpc_pipe_fops;
 702         d_instantiate(dentry, inode);
 703         rpci = RPC_I(inode);
 704         rpci->private = private;
 705         rpci->flags = flags;
 706         rpci->ops = ops;
 707         inode_dir_notify(dir, DN_CREATE);
 708 out:
 709         up(&dir->i_sem);
 710         rpc_release_path(&nd);
 711         return dentry;
 712 err_dput:
 713         dput(dentry);
 714         dentry = ERR_PTR(-ENOMEM);
 715         printk(KERN_WARNING "%s: %s() failed to create pipe %s (errno = %d)\n",
 716                         __FILE__, __FUNCTION__, path, -ENOMEM);
 717         goto out;
 718 }
 719
 720 int
 721 rpc_unlink(char *path)
 722 {
 723         struct nameidata nd;
 724         struct dentry *dentry;
 725         struct inode *dir;
 726         int error;
 727
 728         if ((error = rpc_lookup_parent(path, &nd)) != 0)
 729                 return error;
 730         dir = nd.dentry->d_inode;
 731         down(&dir->i_sem);
 732         dentry = lookup_hash(&nd.last, nd.dentry);
 733         if (IS_ERR(dentry)) {
 734                 error = PTR_ERR(dentry);
 735                 goto out_release;
 736         }
 737         d_drop(dentry);
 738         if (dentry->d_inode) {
 739                 rpc_close_pipes(dentry->d_inode);
 740                 rpc_inode_setowner(dentry->d_inode, NULL);
 741                 error = simple_unlink(dir, dentry);
 742         }
 743         dput(dentry);
 744         inode_dir_notify(dir, DN_DELETE);
 745 out_release:
 746         up(&dir->i_sem);
 747         rpc_release_path(&nd);
 748         return error;
 749 }
 750
 751 /*
 752  * populate the filesystem
 753  */
 754 static struct super_operations s_ops = {
 755         .alloc_inode    = rpc_alloc_inode,
 756         .destroy_inode  = rpc_destroy_inode,
 757         .statfs         = simple_statfs,
 758 };
 759
 760 #define RPCAUTH_GSSMAGIC 0x67596969
 761
 762 static int
 763 rpc_fill_super(struct super_block *sb, void *data, int silent)
 764 {
 765         struct inode *inode;
 766         struct dentry *root;
 767
 768         sb->s_blocksize = PAGE_CACHE_SIZE;
 769         sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
 770         sb->s_magic = RPCAUTH_GSSMAGIC;
 771         sb->s_op = &s_ops;
 772
 773         inode = rpc_get_inode(sb, S_IFDIR | 0755);
 774         if (!inode)
 775                 return -ENOMEM;
 776         root = d_alloc_root(inode);
 777         if (!root) {
 778                 iput(inode);
 779                 return -ENOMEM;
 780         }
 781         if (rpc_populate(root, files, RPCAUTH_Root + 1, RPCAUTH_RootEOF))
 782                 goto out;
 783         sb->s_root = root;
 784         return 0;
 785 out:
 786         d_genocide(root);
 787         dput(root);
 788         return -ENOMEM;
 789 }
 790
 791 static struct super_block *
 792 rpc_get_sb(struct file_system_type *fs_type,
 793                 int flags, const char *dev_name, void *data)
 794 {
 795         return get_sb_single(fs_type, flags, data, rpc_fill_super);
 796 }
 797
 798 static struct file_system_type rpc_pipe_fs_type = {
 799         .owner          = THIS_MODULE,
 800         .name           = "rpc_pipefs",
 801         .get_sb         = rpc_get_sb,
 802         .kill_sb        = kill_litter_super,
 803 };
 804
 805 static void
 806 init_once(void * foo, kmem_cache_t * cachep, unsigned long flags)
 807 {
 808         struct rpc_inode *rpci = (struct rpc_inode *) foo;
 809
 810         if ((flags & (SLAB_CTOR_VERIFY|SLAB_CTOR_CONSTRUCTOR)) ==
 811             SLAB_CTOR_CONSTRUCTOR) {
 812                 inode_init_once(&rpci->vfs_inode);
 813                 rpci->private = NULL;
 814                 rpci->nreaders = 0;
 815                 rpci->nwriters = 0;
 816                 INIT_LIST_HEAD(&rpci->in_upcall);
 817                 INIT_LIST_HEAD(&rpci->pipe);
 818                 rpci->pipelen = 0;
 819                 init_waitqueue_head(&rpci->waitq);
 820                 INIT_WORK(&rpci->queue_timeout, rpc_timeout_upcall_queue, rpci);
 821                 rpci->ops = NULL;
 822         }
 823 }
 824
 825 int register_rpc_pipefs(void)
 826 {
 827         rpc_inode_cachep = kmem_cache_create("rpc_inode_cache",
 828                                              sizeof(struct rpc_inode),
 829                                              0, SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT,
 830                                              init_once, NULL);
 831         if (!rpc_inode_cachep)
 832                 return -ENOMEM;
 833         register_filesystem(&rpc_pipe_fs_type);
 834         return 0;
 835 }
 836
 837 void unregister_rpc_pipefs(void)
 838 {
 839         if (kmem_cache_destroy(rpc_inode_cachep))
 840                 printk(KERN_WARNING "RPC: unable to free inode cache\n");
 841         unregister_filesystem(&rpc_pipe_fs_type);
 842 }