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/sysfs/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 __read_mostly;
  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 __read_mostly;
  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 = -EPIPE;
  80
  81         down(&inode->i_sem);
  82         if (rpci->ops == NULL)
  83                 goto out;
  84         if (rpci->nreaders) {
  85                 list_add_tail(&msg->list, &rpci->pipe);
  86                 rpci->pipelen += msg->len;
  87                 res = 0;
  88         } else if (rpci->flags & RPC_PIPE_WAIT_FOR_OPEN) {
  89                 if (list_empty(&rpci->pipe))
  90                         schedule_delayed_work(&rpci->queue_timeout,
  91                                         RPC_UPCALL_TIMEOUT);
  92                 list_add_tail(&msg->list, &rpci->pipe);
  93                 rpci->pipelen += msg->len;
  94                 res = 0;
  95         }
  96 out:
  97         up(&inode->i_sem);
  98         wake_up(&rpci->waitq);
  99         return res;
 100 }
 101
 102 static inline void
 103 rpc_inode_setowner(struct inode *inode, void *private)
 104 {
 105         RPC_I(inode)->private = private;
 106 }
 107
 108 static void
 109 rpc_close_pipes(struct inode *inode)
 110 {
 111         struct rpc_inode *rpci = RPC_I(inode);
 112
 113         cancel_delayed_work(&rpci->queue_timeout);
 114         flush_scheduled_work();
 115         down(&inode->i_sem);
 116         if (rpci->ops != NULL) {
 117                 rpci->nreaders = 0;
 118                 __rpc_purge_upcall(inode, -EPIPE);
 119                 rpci->nwriters = 0;
 120                 if (rpci->ops->release_pipe)
 121                         rpci->ops->release_pipe(inode);
 122                 rpci->ops = NULL;
 123         }
 124         rpc_inode_setowner(inode, NULL);
 125         up(&inode->i_sem);
 126 }
 127
 128 static struct inode *
 129 rpc_alloc_inode(struct super_block *sb)
 130 {
 131         struct rpc_inode *rpci;
 132         rpci = (struct rpc_inode *)kmem_cache_alloc(rpc_inode_cachep, SLAB_KERNEL);
 133         if (!rpci)
 134                 return NULL;
 135         return &rpci->vfs_inode;
 136 }
 137
 138 static void
 139 rpc_destroy_inode(struct inode *inode)
 140 {
 141         kmem_cache_free(rpc_inode_cachep, RPC_I(inode));
 142 }
 143
 144 static int
 145 rpc_pipe_open(struct inode *inode, struct file *filp)
 146 {
 147         struct rpc_inode *rpci = RPC_I(inode);
 148         int res = -ENXIO;
 149
 150         down(&inode->i_sem);
 151         if (rpci->ops != NULL) {
 152                 if (filp->f_mode & FMODE_READ)
 153                         rpci->nreaders ++;
 154                 if (filp->f_mode & FMODE_WRITE)
 155                         rpci->nwriters ++;
 156                 res = 0;
 157         }
 158         up(&inode->i_sem);
 159         return res;
 160 }
 161
 162 static int
 163 rpc_pipe_release(struct inode *inode, struct file *filp)
 164 {
 165         struct rpc_inode *rpci = RPC_I(filp->f_dentry->d_inode);
 166         struct rpc_pipe_msg *msg;
 167
 168         down(&inode->i_sem);
 169         if (rpci->ops == NULL)
 170                 goto out;
 171         msg = (struct rpc_pipe_msg *)filp->private_data;
 172         if (msg != NULL) {
 173                 msg->errno = -EPIPE;
 174                 list_del_init(&msg->list);
 175                 rpci->ops->destroy_msg(msg);
 176         }
 177         if (filp->f_mode & FMODE_WRITE)
 178                 rpci->nwriters --;
 179         if (filp->f_mode & FMODE_READ)
 180                 rpci->nreaders --;
 181         if (!rpci->nreaders)
 182                 __rpc_purge_upcall(inode, -EPIPE);
 183         if (rpci->ops->release_pipe)
 184                 rpci->ops->release_pipe(inode);
 185 out:
 186         up(&inode->i_sem);
 187         return 0;
 188 }
 189
 190 static ssize_t
 191 rpc_pipe_read(struct file *filp, char __user *buf, size_t len, loff_t *offset)
 192 {
 193         struct inode *inode = filp->f_dentry->d_inode;
 194         struct rpc_inode *rpci = RPC_I(inode);
 195         struct rpc_pipe_msg *msg;
 196         int res = 0;
 197
 198         down(&inode->i_sem);
 199         if (rpci->ops == NULL) {
 200                 res = -EPIPE;
 201                 goto out_unlock;
 202         }
 203         msg = filp->private_data;
 204         if (msg == NULL) {
 205                 if (!list_empty(&rpci->pipe)) {
 206                         msg = list_entry(rpci->pipe.next,
 207                                         struct rpc_pipe_msg,
 208                                         list);
 209                         list_move(&msg->list, &rpci->in_upcall);
 210                         rpci->pipelen -= msg->len;
 211                         filp->private_data = msg;
 212                         msg->copied = 0;
 213                 }
 214                 if (msg == NULL)
 215                         goto out_unlock;
 216         }
 217         /* NOTE: it is up to the callback to update msg->copied */
 218         res = rpci->ops->upcall(filp, msg, buf, len);
 219         if (res < 0 || msg->len == msg->copied) {
 220                 filp->private_data = NULL;
 221                 list_del_init(&msg->list);
 222                 rpci->ops->destroy_msg(msg);
 223         }
 224 out_unlock:
 225         up(&inode->i_sem);
 226         return res;
 227 }
 228
 229 static ssize_t
 230 rpc_pipe_write(struct file *filp, const char __user *buf, size_t len, loff_t *offset)
 231 {
 232         struct inode *inode = filp->f_dentry->d_inode;
 233         struct rpc_inode *rpci = RPC_I(inode);
 234         int res;
 235
 236         down(&inode->i_sem);
 237         res = -EPIPE;
 238         if (rpci->ops != NULL)
 239                 res = rpci->ops->downcall(filp, buf, len);
 240         up(&inode->i_sem);
 241         return res;
 242 }
 243
 244 static unsigned int
 245 rpc_pipe_poll(struct file *filp, struct poll_table_struct *wait)
 246 {
 247         struct rpc_inode *rpci;
 248         unsigned int mask = 0;
 249
 250         rpci = RPC_I(filp->f_dentry->d_inode);
 251         poll_wait(filp, &rpci->waitq, wait);
 252
 253         mask = POLLOUT | POLLWRNORM;
 254         if (rpci->ops == NULL)
 255                 mask |= POLLERR | POLLHUP;
 256         if (!list_empty(&rpci->pipe))
 257                 mask |= POLLIN | POLLRDNORM;
 258         return mask;
 259 }
 260
 261 static int
 262 rpc_pipe_ioctl(struct inode *ino, struct file *filp,
 263                 unsigned int cmd, unsigned long arg)
 264 {
 265         struct rpc_inode *rpci = RPC_I(filp->f_dentry->d_inode);
 266         int len;
 267
 268         switch (cmd) {
 269         case FIONREAD:
 270                 if (rpci->ops == NULL)
 271                         return -EPIPE;
 272                 len = rpci->pipelen;
 273                 if (filp->private_data) {
 274                         struct rpc_pipe_msg *msg;
 275                         msg = (struct rpc_pipe_msg *)filp->private_data;
 276                         len += msg->len - msg->copied;
 277                 }
 278                 return put_user(len, (int __user *)arg);
 279         default:
 280                 return -EINVAL;
 281         }
 282 }
 283
 284 static 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                                 simple_unlink(dir, dentry);
 510                         }
 511                         dput(dentry);
 512                 } while (n);
 513                 goto repeat;
 514         }
 515         up(&dir->i_sem);
 516 }
 517
 518 static int
 519 rpc_populate(struct dentry *parent,
 520                 struct rpc_filelist *files,
 521                 int start, int eof)
 522 {
 523         struct inode *inode, *dir = parent->d_inode;
 524         void *private = RPC_I(dir)->private;
 525         struct dentry *dentry;
 526         int mode, i;
 527
 528         down(&dir->i_sem);
 529         for (i = start; i < eof; i++) {
 530                 dentry = d_alloc_name(parent, files[i].name);
 531                 if (!dentry)
 532                         goto out_bad;
 533                 mode = files[i].mode;
 534                 inode = rpc_get_inode(dir->i_sb, mode);
 535                 if (!inode) {
 536                         dput(dentry);
 537                         goto out_bad;
 538                 }
 539                 inode->i_ino = i;
 540                 if (files[i].i_fop)
 541                         inode->i_fop = files[i].i_fop;
 542                 if (private)
 543                         rpc_inode_setowner(inode, private);
 544                 if (S_ISDIR(mode))
 545                         dir->i_nlink++;
 546                 d_add(dentry, inode);
 547         }
 548         up(&dir->i_sem);
 549         return 0;
 550 out_bad:
 551         up(&dir->i_sem);
 552         printk(KERN_WARNING "%s: %s failed to populate directory %s\n",
 553                         __FILE__, __FUNCTION__, parent->d_name.name);
 554         return -ENOMEM;
 555 }
 556
 557 static int
 558 __rpc_mkdir(struct inode *dir, struct dentry *dentry)
 559 {
 560         struct inode *inode;
 561
 562         inode = rpc_get_inode(dir->i_sb, S_IFDIR | S_IRUSR | S_IXUSR);
 563         if (!inode)
 564                 goto out_err;
 565         inode->i_ino = iunique(dir->i_sb, 100);
 566         d_instantiate(dentry, inode);
 567         dir->i_nlink++;
 568         inode_dir_notify(dir, DN_CREATE);
 569         rpc_get_mount();
 570         return 0;
 571 out_err:
 572         printk(KERN_WARNING "%s: %s failed to allocate inode for dentry %s\n",
 573                         __FILE__, __FUNCTION__, dentry->d_name.name);
 574         return -ENOMEM;
 575 }
 576
 577 static int
 578 __rpc_rmdir(struct inode *dir, struct dentry *dentry)
 579 {
 580         int error;
 581
 582         shrink_dcache_parent(dentry);
 583         if (dentry->d_inode)
 584                 rpc_close_pipes(dentry->d_inode);
 585         if ((error = simple_rmdir(dir, dentry)) != 0)
 586                 return error;
 587         if (!error) {
 588                 inode_dir_notify(dir, DN_DELETE);
 589                 d_drop(dentry);
 590                 rpc_put_mount();
 591         }
 592         return 0;
 593 }
 594
 595 static struct dentry *
 596 rpc_lookup_negative(char *path, struct nameidata *nd)
 597 {
 598         struct dentry *dentry;
 599         struct inode *dir;
 600         int error;
 601
 602         if ((error = rpc_lookup_parent(path, nd)) != 0)
 603                 return ERR_PTR(error);
 604         dir = nd->dentry->d_inode;
 605         down(&dir->i_sem);
 606         dentry = lookup_hash(&nd->last, nd->dentry);
 607         if (IS_ERR(dentry))
 608                 goto out_err;
 609         if (dentry->d_inode) {
 610                 dput(dentry);
 611                 dentry = ERR_PTR(-EEXIST);
 612                 goto out_err;
 613         }
 614         return dentry;
 615 out_err:
 616         up(&dir->i_sem);
 617         rpc_release_path(nd);
 618         return dentry;
 619 }
 620
 621
 622 struct dentry *
 623 rpc_mkdir(char *path, struct rpc_clnt *rpc_client)
 624 {
 625         struct nameidata nd;
 626         struct dentry *dentry;
 627         struct inode *dir;
 628         int error;
 629
 630         dentry = rpc_lookup_negative(path, &nd);
 631         if (IS_ERR(dentry))
 632                 return dentry;
 633         dir = nd.dentry->d_inode;
 634         if ((error = __rpc_mkdir(dir, dentry)) != 0)
 635                 goto err_dput;
 636         RPC_I(dentry->d_inode)->private = rpc_client;
 637         error = rpc_populate(dentry, authfiles,
 638                         RPCAUTH_info, RPCAUTH_EOF);
 639         if (error)
 640                 goto err_depopulate;
 641 out:
 642         up(&dir->i_sem);
 643         rpc_release_path(&nd);
 644         return dentry;
 645 err_depopulate:
 646         rpc_depopulate(dentry);
 647         __rpc_rmdir(dir, dentry);
 648 err_dput:
 649         dput(dentry);
 650         printk(KERN_WARNING "%s: %s() failed to create directory %s (errno = %d)\n",
 651                         __FILE__, __FUNCTION__, path, error);
 652         dentry = ERR_PTR(error);
 653         goto out;
 654 }
 655
 656 int
 657 rpc_rmdir(char *path)
 658 {
 659         struct nameidata nd;
 660         struct dentry *dentry;
 661         struct inode *dir;
 662         int error;
 663
 664         if ((error = rpc_lookup_parent(path, &nd)) != 0)
 665                 return error;
 666         dir = nd.dentry->d_inode;
 667         down(&dir->i_sem);
 668         dentry = lookup_hash(&nd.last, nd.dentry);
 669         if (IS_ERR(dentry)) {
 670                 error = PTR_ERR(dentry);
 671                 goto out_release;
 672         }
 673         rpc_depopulate(dentry);
 674         error = __rpc_rmdir(dir, dentry);
 675         dput(dentry);
 676 out_release:
 677         up(&dir->i_sem);
 678         rpc_release_path(&nd);
 679         return error;
 680 }
 681
 682 struct dentry *
 683 rpc_mkpipe(char *path, void *private, struct rpc_pipe_ops *ops, int flags)
 684 {
 685         struct nameidata nd;
 686         struct dentry *dentry;
 687         struct inode *dir, *inode;
 688         struct rpc_inode *rpci;
 689
 690         dentry = rpc_lookup_negative(path, &nd);
 691         if (IS_ERR(dentry))
 692                 return dentry;
 693         dir = nd.dentry->d_inode;
 694         inode = rpc_get_inode(dir->i_sb, S_IFSOCK | S_IRUSR | S_IWUSR);
 695         if (!inode)
 696                 goto err_dput;
 697         inode->i_ino = iunique(dir->i_sb, 100);
 698         inode->i_fop = &rpc_pipe_fops;
 699         d_instantiate(dentry, inode);
 700         rpci = RPC_I(inode);
 701         rpci->private = private;
 702         rpci->flags = flags;
 703         rpci->ops = ops;
 704         inode_dir_notify(dir, DN_CREATE);
 705 out:
 706         up(&dir->i_sem);
 707         rpc_release_path(&nd);
 708         return dentry;
 709 err_dput:
 710         dput(dentry);
 711         dentry = ERR_PTR(-ENOMEM);
 712         printk(KERN_WARNING "%s: %s() failed to create pipe %s (errno = %d)\n",
 713                         __FILE__, __FUNCTION__, path, -ENOMEM);
 714         goto out;
 715 }
 716
 717 int
 718 rpc_unlink(char *path)
 719 {
 720         struct nameidata nd;
 721         struct dentry *dentry;
 722         struct inode *dir;
 723         int error;
 724
 725         if ((error = rpc_lookup_parent(path, &nd)) != 0)
 726                 return error;
 727         dir = nd.dentry->d_inode;
 728         down(&dir->i_sem);
 729         dentry = lookup_hash(&nd.last, nd.dentry);
 730         if (IS_ERR(dentry)) {
 731                 error = PTR_ERR(dentry);
 732                 goto out_release;
 733         }
 734         d_drop(dentry);
 735         if (dentry->d_inode) {
 736                 rpc_close_pipes(dentry->d_inode);
 737                 error = simple_unlink(dir, dentry);
 738         }
 739         dput(dentry);
 740         inode_dir_notify(dir, DN_DELETE);
 741 out_release:
 742         up(&dir->i_sem);
 743         rpc_release_path(&nd);
 744         return error;
 745 }
 746
 747 /*
 748  * populate the filesystem
 749  */
 750 static struct super_operations s_ops = {
 751         .alloc_inode    = rpc_alloc_inode,
 752         .destroy_inode  = rpc_destroy_inode,
 753         .statfs         = simple_statfs,
 754 };
 755
 756 #define RPCAUTH_GSSMAGIC 0x67596969
 757
 758 static int
 759 rpc_fill_super(struct super_block *sb, void *data, int silent)
 760 {
 761         struct inode *inode;
 762         struct dentry *root;
 763
 764         sb->s_blocksize = PAGE_CACHE_SIZE;
 765         sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
 766         sb->s_magic = RPCAUTH_GSSMAGIC;
 767         sb->s_op = &s_ops;
 768         sb->s_time_gran = 1;
 769
 770         inode = rpc_get_inode(sb, S_IFDIR | 0755);
 771         if (!inode)
 772                 return -ENOMEM;
 773         root = d_alloc_root(inode);
 774         if (!root) {
 775                 iput(inode);
 776                 return -ENOMEM;
 777         }
 778         if (rpc_populate(root, files, RPCAUTH_Root + 1, RPCAUTH_RootEOF))
 779                 goto out;
 780         sb->s_root = root;
 781         return 0;
 782 out:
 783         d_genocide(root);
 784         dput(root);
 785         return -ENOMEM;
 786 }
 787
 788 static struct super_block *
 789 rpc_get_sb(struct file_system_type *fs_type,
 790                 int flags, const char *dev_name, void *data)
 791 {
 792         return get_sb_single(fs_type, flags, data, rpc_fill_super);
 793 }
 794
 795 static struct file_system_type rpc_pipe_fs_type = {
 796         .owner          = THIS_MODULE,
 797         .name           = "rpc_pipefs",
 798         .get_sb         = rpc_get_sb,
 799         .kill_sb        = kill_litter_super,
 800 };
 801
 802 static void
 803 init_once(void * foo, kmem_cache_t * cachep, unsigned long flags)
 804 {
 805         struct rpc_inode *rpci = (struct rpc_inode *) foo;
 806
 807         if ((flags & (SLAB_CTOR_VERIFY|SLAB_CTOR_CONSTRUCTOR)) ==
 808             SLAB_CTOR_CONSTRUCTOR) {
 809                 inode_init_once(&rpci->vfs_inode);
 810                 rpci->private = NULL;
 811                 rpci->nreaders = 0;
 812                 rpci->nwriters = 0;
 813                 INIT_LIST_HEAD(&rpci->in_upcall);
 814                 INIT_LIST_HEAD(&rpci->pipe);
 815                 rpci->pipelen = 0;
 816                 init_waitqueue_head(&rpci->waitq);
 817                 INIT_WORK(&rpci->queue_timeout, rpc_timeout_upcall_queue, rpci);
 818                 rpci->ops = NULL;
 819         }
 820 }
 821
 822 int register_rpc_pipefs(void)
 823 {
 824         rpc_inode_cachep = kmem_cache_create("rpc_inode_cache",
 825                                              sizeof(struct rpc_inode),
 826                                              0, SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT,
 827                                              init_once, NULL);
 828         if (!rpc_inode_cachep)
 829                 return -ENOMEM;
 830         register_filesystem(&rpc_pipe_fs_type);
 831         return 0;
 832 }
 833
 834 void unregister_rpc_pipefs(void)
 835 {
 836         if (kmem_cache_destroy(rpc_inode_cachep))
 837                 printk(KERN_WARNING "RPC: unable to free inode cache\n");
 838         unregister_filesystem(&rpc_pipe_fs_type);
 839 }