err.no Git - linux-2.6/blob - 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/module.h>
  12 #include <linux/slab.h>
  13 #include <linux/string.h>
  14 #include <linux/pagemap.h>
  15 #include <linux/mount.h>
  16 #include <linux/namei.h>
  17 #include <linux/dnotify.h>
  18 #include <linux/kernel.h>
  19
  20 #include <asm/ioctls.h>
  21 #include <linux/fs.h>
  22 #include <linux/poll.h>
  23 #include <linux/wait.h>
  24 #include <linux/seq_file.h>
  25
  26 #include <linux/sunrpc/clnt.h>
  27 #include <linux/workqueue.h>
  28 #include <linux/sunrpc/rpc_pipe_fs.h>
  29
  30 static struct vfsmount *rpc_mount __read_mostly;
  31 static int rpc_mount_count;
  32
  33 static struct file_system_type rpc_pipe_fs_type;
  34
  35
  36 static struct kmem_cache *rpc_inode_cachep __read_mostly;
  37
  38 #define RPC_UPCALL_TIMEOUT (30*HZ)
  39
  40 static void rpc_purge_list(struct rpc_inode *rpci, struct list_head *head,
  41                 void (*destroy_msg)(struct rpc_pipe_msg *), int err)
  42 {
  43         struct rpc_pipe_msg *msg;
  44
  45         if (list_empty(head))
  46                 return;
  47         do {
  48                 msg = list_entry(head->next, struct rpc_pipe_msg, list);
  49                 list_del(&msg->list);
  50                 msg->errno = err;
  51                 destroy_msg(msg);
  52         } while (!list_empty(head));
  53         wake_up(&rpci->waitq);
  54 }
  55
  56 static void
  57 rpc_timeout_upcall_queue(struct work_struct *work)
  58 {
  59         LIST_HEAD(free_list);
  60         struct rpc_inode *rpci =
  61                 container_of(work, struct rpc_inode, queue_timeout.work);
  62         struct inode *inode = &rpci->vfs_inode;
  63         void (*destroy_msg)(struct rpc_pipe_msg *);
  64
  65         spin_lock(&inode->i_lock);
  66         if (rpci->ops == NULL) {
  67                 spin_unlock(&inode->i_lock);
  68                 return;
  69         }
  70         destroy_msg = rpci->ops->destroy_msg;
  71         if (rpci->nreaders == 0) {
  72                 list_splice_init(&rpci->pipe, &free_list);
  73                 rpci->pipelen = 0;
  74         }
  75         spin_unlock(&inode->i_lock);
  76         rpc_purge_list(rpci, &free_list, destroy_msg, -ETIMEDOUT);
  77 }
  78
  79 int
  80 rpc_queue_upcall(struct inode *inode, struct rpc_pipe_msg *msg)
  81 {
  82         struct rpc_inode *rpci = RPC_I(inode);
  83         int res = -EPIPE;
  84
  85         spin_lock(&inode->i_lock);
  86         if (rpci->ops == NULL)
  87                 goto out;
  88         if (rpci->nreaders) {
  89                 list_add_tail(&msg->list, &rpci->pipe);
  90                 rpci->pipelen += msg->len;
  91                 res = 0;
  92         } else if (rpci->flags & RPC_PIPE_WAIT_FOR_OPEN) {
  93                 if (list_empty(&rpci->pipe))
  94                         queue_delayed_work(rpciod_workqueue,
  95                                         &rpci->queue_timeout,
  96                                         RPC_UPCALL_TIMEOUT);
  97                 list_add_tail(&msg->list, &rpci->pipe);
  98                 rpci->pipelen += msg->len;
  99                 res = 0;
 100         }
 101 out:
 102         spin_unlock(&inode->i_lock);
 103         wake_up(&rpci->waitq);
 104         return res;
 105 }
 106
 107 static inline void
 108 rpc_inode_setowner(struct inode *inode, void *private)
 109 {
 110         RPC_I(inode)->private = private;
 111 }
 112
 113 static void
 114 rpc_close_pipes(struct inode *inode)
 115 {
 116         struct rpc_inode *rpci = RPC_I(inode);
 117         struct rpc_pipe_ops *ops;
 118
 119         mutex_lock(&inode->i_mutex);
 120         ops = rpci->ops;
 121         if (ops != NULL) {
 122                 LIST_HEAD(free_list);
 123
 124                 spin_lock(&inode->i_lock);
 125                 rpci->nreaders = 0;
 126                 list_splice_init(&rpci->in_upcall, &free_list);
 127                 list_splice_init(&rpci->pipe, &free_list);
 128                 rpci->pipelen = 0;
 129                 rpci->ops = NULL;
 130                 spin_unlock(&inode->i_lock);
 131                 rpc_purge_list(rpci, &free_list, ops->destroy_msg, -EPIPE);
 132                 rpci->nwriters = 0;
 133                 if (ops->release_pipe)
 134                         ops->release_pipe(inode);
 135                 cancel_delayed_work(&rpci->queue_timeout);
 136                 flush_workqueue(rpciod_workqueue);
 137         }
 138         rpc_inode_setowner(inode, NULL);
 139         mutex_unlock(&inode->i_mutex);
 140 }
 141
 142 static struct inode *
 143 rpc_alloc_inode(struct super_block *sb)
 144 {
 145         struct rpc_inode *rpci;
 146         rpci = (struct rpc_inode *)kmem_cache_alloc(rpc_inode_cachep, GFP_KERNEL);
 147         if (!rpci)
 148                 return NULL;
 149         return &rpci->vfs_inode;
 150 }
 151
 152 static void
 153 rpc_destroy_inode(struct inode *inode)
 154 {
 155         kmem_cache_free(rpc_inode_cachep, RPC_I(inode));
 156 }
 157
 158 static int
 159 rpc_pipe_open(struct inode *inode, struct file *filp)
 160 {
 161         struct rpc_inode *rpci = RPC_I(inode);
 162         int res = -ENXIO;
 163
 164         mutex_lock(&inode->i_mutex);
 165         if (rpci->ops != NULL) {
 166                 if (filp->f_mode & FMODE_READ)
 167                         rpci->nreaders ++;
 168                 if (filp->f_mode & FMODE_WRITE)
 169                         rpci->nwriters ++;
 170                 res = 0;
 171         }
 172         mutex_unlock(&inode->i_mutex);
 173         return res;
 174 }
 175
 176 static int
 177 rpc_pipe_release(struct inode *inode, struct file *filp)
 178 {
 179         struct rpc_inode *rpci = RPC_I(inode);
 180         struct rpc_pipe_msg *msg;
 181
 182         mutex_lock(&inode->i_mutex);
 183         if (rpci->ops == NULL)
 184                 goto out;
 185         msg = (struct rpc_pipe_msg *)filp->private_data;
 186         if (msg != NULL) {
 187                 spin_lock(&inode->i_lock);
 188                 msg->errno = -EAGAIN;
 189                 list_del(&msg->list);
 190                 spin_unlock(&inode->i_lock);
 191                 rpci->ops->destroy_msg(msg);
 192         }
 193         if (filp->f_mode & FMODE_WRITE)
 194                 rpci->nwriters --;
 195         if (filp->f_mode & FMODE_READ) {
 196                 rpci->nreaders --;
 197                 if (rpci->nreaders == 0) {
 198                         LIST_HEAD(free_list);
 199                         spin_lock(&inode->i_lock);
 200                         list_splice_init(&rpci->pipe, &free_list);
 201                         rpci->pipelen = 0;
 202                         spin_unlock(&inode->i_lock);
 203                         rpc_purge_list(rpci, &free_list,
 204                                         rpci->ops->destroy_msg, -EAGAIN);
 205                 }
 206         }
 207         if (rpci->ops->release_pipe)
 208                 rpci->ops->release_pipe(inode);
 209 out:
 210         mutex_unlock(&inode->i_mutex);
 211         return 0;
 212 }
 213
 214 static ssize_t
 215 rpc_pipe_read(struct file *filp, char __user *buf, size_t len, loff_t *offset)
 216 {
 217         struct inode *inode = filp->f_path.dentry->d_inode;
 218         struct rpc_inode *rpci = RPC_I(inode);
 219         struct rpc_pipe_msg *msg;
 220         int res = 0;
 221
 222         mutex_lock(&inode->i_mutex);
 223         if (rpci->ops == NULL) {
 224                 res = -EPIPE;
 225                 goto out_unlock;
 226         }
 227         msg = filp->private_data;
 228         if (msg == NULL) {
 229                 spin_lock(&inode->i_lock);
 230                 if (!list_empty(&rpci->pipe)) {
 231                         msg = list_entry(rpci->pipe.next,
 232                                         struct rpc_pipe_msg,
 233                                         list);
 234                         list_move(&msg->list, &rpci->in_upcall);
 235                         rpci->pipelen -= msg->len;
 236                         filp->private_data = msg;
 237                         msg->copied = 0;
 238                 }
 239                 spin_unlock(&inode->i_lock);
 240                 if (msg == NULL)
 241                         goto out_unlock;
 242         }
 243         /* NOTE: it is up to the callback to update msg->copied */
 244         res = rpci->ops->upcall(filp, msg, buf, len);
 245         if (res < 0 || msg->len == msg->copied) {
 246                 filp->private_data = NULL;
 247                 spin_lock(&inode->i_lock);
 248                 list_del(&msg->list);
 249                 spin_unlock(&inode->i_lock);
 250                 rpci->ops->destroy_msg(msg);
 251         }
 252 out_unlock:
 253         mutex_unlock(&inode->i_mutex);
 254         return res;
 255 }
 256
 257 static ssize_t
 258 rpc_pipe_write(struct file *filp, const char __user *buf, size_t len, loff_t *offset)
 259 {
 260         struct inode *inode = filp->f_path.dentry->d_inode;
 261         struct rpc_inode *rpci = RPC_I(inode);
 262         int res;
 263
 264         mutex_lock(&inode->i_mutex);
 265         res = -EPIPE;
 266         if (rpci->ops != NULL)
 267                 res = rpci->ops->downcall(filp, buf, len);
 268         mutex_unlock(&inode->i_mutex);
 269         return res;
 270 }
 271
 272 static unsigned int
 273 rpc_pipe_poll(struct file *filp, struct poll_table_struct *wait)
 274 {
 275         struct rpc_inode *rpci;
 276         unsigned int mask = 0;
 277
 278         rpci = RPC_I(filp->f_path.dentry->d_inode);
 279         poll_wait(filp, &rpci->waitq, wait);
 280
 281         mask = POLLOUT | POLLWRNORM;
 282         if (rpci->ops == NULL)
 283                 mask |= POLLERR | POLLHUP;
 284         if (!list_empty(&rpci->pipe))
 285                 mask |= POLLIN | POLLRDNORM;
 286         return mask;
 287 }
 288
 289 static int
 290 rpc_pipe_ioctl(struct inode *ino, struct file *filp,
 291                 unsigned int cmd, unsigned long arg)
 292 {
 293         struct rpc_inode *rpci = RPC_I(filp->f_path.dentry->d_inode);
 294         int len;
 295
 296         switch (cmd) {
 297         case FIONREAD:
 298                 if (rpci->ops == NULL)
 299                         return -EPIPE;
 300                 len = rpci->pipelen;
 301                 if (filp->private_data) {
 302                         struct rpc_pipe_msg *msg;
 303                         msg = (struct rpc_pipe_msg *)filp->private_data;
 304                         len += msg->len - msg->copied;
 305                 }
 306                 return put_user(len, (int __user *)arg);
 307         default:
 308                 return -EINVAL;
 309         }
 310 }
 311
 312 static const struct file_operations rpc_pipe_fops = {
 313         .owner          = THIS_MODULE,
 314         .llseek         = no_llseek,
 315         .read           = rpc_pipe_read,
 316         .write          = rpc_pipe_write,
 317         .poll           = rpc_pipe_poll,
 318         .ioctl          = rpc_pipe_ioctl,
 319         .open           = rpc_pipe_open,
 320         .release        = rpc_pipe_release,
 321 };
 322
 323 static int
 324 rpc_show_info(struct seq_file *m, void *v)
 325 {
 326         struct rpc_clnt *clnt = m->private;
 327
 328         seq_printf(m, "RPC server: %s\n", clnt->cl_server);
 329         seq_printf(m, "service: %s (%d) version %d\n", clnt->cl_protname,
 330                         clnt->cl_prog, clnt->cl_vers);
 331         seq_printf(m, "address: %s\n", rpc_peeraddr2str(clnt, RPC_DISPLAY_ADDR));
 332         seq_printf(m, "protocol: %s\n", rpc_peeraddr2str(clnt, RPC_DISPLAY_PROTO));
 333         return 0;
 334 }
 335
 336 static int
 337 rpc_info_open(struct inode *inode, struct file *file)
 338 {
 339         struct rpc_clnt *clnt;
 340         int ret = single_open(file, rpc_show_info, NULL);
 341
 342         if (!ret) {
 343                 struct seq_file *m = file->private_data;
 344                 mutex_lock(&inode->i_mutex);
 345                 clnt = RPC_I(inode)->private;
 346                 if (clnt) {
 347                         atomic_inc(&clnt->cl_users);
 348                         m->private = clnt;
 349                 } else {
 350                         single_release(inode, file);
 351                         ret = -EINVAL;
 352                 }
 353                 mutex_unlock(&inode->i_mutex);
 354         }
 355         return ret;
 356 }
 357
 358 static int
 359 rpc_info_release(struct inode *inode, struct file *file)
 360 {
 361         struct seq_file *m = file->private_data;
 362         struct rpc_clnt *clnt = (struct rpc_clnt *)m->private;
 363
 364         if (clnt)
 365                 rpc_release_client(clnt);
 366         return single_release(inode, file);
 367 }
 368
 369 static const struct file_operations rpc_info_operations = {
 370         .owner          = THIS_MODULE,
 371         .open           = rpc_info_open,
 372         .read           = seq_read,
 373         .llseek         = seq_lseek,
 374         .release        = rpc_info_release,
 375 };
 376
 377
 378 /*
 379  * We have a single directory with 1 node in it.
 380  */
 381 enum {
 382         RPCAUTH_Root = 1,
 383         RPCAUTH_lockd,
 384         RPCAUTH_mount,
 385         RPCAUTH_nfs,
 386         RPCAUTH_portmap,
 387         RPCAUTH_statd,
 388         RPCAUTH_RootEOF
 389 };
 390
 391 /*
 392  * Description of fs contents.
 393  */
 394 struct rpc_filelist {
 395         char *name;
 396         const struct file_operations *i_fop;
 397         int mode;
 398 };
 399
 400 static struct rpc_filelist files[] = {
 401         [RPCAUTH_lockd] = {
 402                 .name = "lockd",
 403                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
 404         },
 405         [RPCAUTH_mount] = {
 406                 .name = "mount",
 407                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
 408         },
 409         [RPCAUTH_nfs] = {
 410                 .name = "nfs",
 411                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
 412         },
 413         [RPCAUTH_portmap] = {
 414                 .name = "portmap",
 415                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
 416         },
 417         [RPCAUTH_statd] = {
 418                 .name = "statd",
 419                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
 420         },
 421 };
 422
 423 enum {
 424         RPCAUTH_info = 2,
 425         RPCAUTH_EOF
 426 };
 427
 428 static struct rpc_filelist authfiles[] = {
 429         [RPCAUTH_info] = {
 430                 .name = "info",
 431                 .i_fop = &rpc_info_operations,
 432                 .mode = S_IFREG | S_IRUSR,
 433         },
 434 };
 435
 436 struct vfsmount *rpc_get_mount(void)
 437 {
 438         int err;
 439
 440         err = simple_pin_fs(&rpc_pipe_fs_type, &rpc_mount, &rpc_mount_count);
 441         if (err != 0)
 442                 return ERR_PTR(err);
 443         return rpc_mount;
 444 }
 445
 446 void rpc_put_mount(void)
 447 {
 448         simple_release_fs(&rpc_mount, &rpc_mount_count);
 449 }
 450
 451 static int
 452 rpc_lookup_parent(char *path, struct nameidata *nd)
 453 {
 454         if (path[0] == '\0')
 455                 return -ENOENT;
 456         nd->mnt = rpc_get_mount();
 457         if (IS_ERR(nd->mnt)) {
 458                 printk(KERN_WARNING "%s: %s failed to mount "
 459                                "pseudofilesystem \n", __FILE__, __FUNCTION__);
 460                 return PTR_ERR(nd->mnt);
 461         }
 462         mntget(nd->mnt);
 463         nd->dentry = dget(rpc_mount->mnt_root);
 464         nd->last_type = LAST_ROOT;
 465         nd->flags = LOOKUP_PARENT;
 466         nd->depth = 0;
 467
 468         if (path_walk(path, nd)) {
 469                 printk(KERN_WARNING "%s: %s failed to find path %s\n",
 470                                 __FILE__, __FUNCTION__, path);
 471                 rpc_put_mount();
 472                 return -ENOENT;
 473         }
 474         return 0;
 475 }
 476
 477 static void
 478 rpc_release_path(struct nameidata *nd)
 479 {
 480         path_release(nd);
 481         rpc_put_mount();
 482 }
 483
 484 static struct inode *
 485 rpc_get_inode(struct super_block *sb, int mode)
 486 {
 487         struct inode *inode = new_inode(sb);
 488         if (!inode)
 489                 return NULL;
 490         inode->i_mode = mode;
 491         inode->i_uid = inode->i_gid = 0;
 492         inode->i_blocks = 0;
 493         inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
 494         switch(mode & S_IFMT) {
 495                 case S_IFDIR:
 496                         inode->i_fop = &simple_dir_operations;
 497                         inode->i_op = &simple_dir_inode_operations;
 498                         inc_nlink(inode);
 499                 default:
 500                         break;
 501         }
 502         return inode;
 503 }
 504
 505 /*
 506  * FIXME: This probably has races.
 507  */
 508 static void
 509 rpc_depopulate(struct dentry *parent)
 510 {
 511         struct inode *dir = parent->d_inode;
 512         struct list_head *pos, *next;
 513         struct dentry *dentry, *dvec[10];
 514         int n = 0;
 515
 516         mutex_lock_nested(&dir->i_mutex, I_MUTEX_CHILD);
 517 repeat:
 518         spin_lock(&dcache_lock);
 519         list_for_each_safe(pos, next, &parent->d_subdirs) {
 520                 dentry = list_entry(pos, struct dentry, d_u.d_child);
 521                 spin_lock(&dentry->d_lock);
 522                 if (!d_unhashed(dentry)) {
 523                         dget_locked(dentry);
 524                         __d_drop(dentry);
 525                         spin_unlock(&dentry->d_lock);
 526                         dvec[n++] = dentry;
 527                         if (n == ARRAY_SIZE(dvec))
 528                                 break;
 529                 } else
 530                         spin_unlock(&dentry->d_lock);
 531         }
 532         spin_unlock(&dcache_lock);
 533         if (n) {
 534                 do {
 535                         dentry = dvec[--n];
 536                         if (dentry->d_inode) {
 537                                 rpc_close_pipes(dentry->d_inode);
 538                                 simple_unlink(dir, dentry);
 539                         }
 540                         inode_dir_notify(dir, DN_DELETE);
 541                         dput(dentry);
 542                 } while (n);
 543                 goto repeat;
 544         }
 545         mutex_unlock(&dir->i_mutex);
 546 }
 547
 548 static int
 549 rpc_populate(struct dentry *parent,
 550                 struct rpc_filelist *files,
 551                 int start, int eof)
 552 {
 553         struct inode *inode, *dir = parent->d_inode;
 554         void *private = RPC_I(dir)->private;
 555         struct dentry *dentry;
 556         int mode, i;
 557
 558         mutex_lock(&dir->i_mutex);
 559         for (i = start; i < eof; i++) {
 560                 dentry = d_alloc_name(parent, files[i].name);
 561                 if (!dentry)
 562                         goto out_bad;
 563                 mode = files[i].mode;
 564                 inode = rpc_get_inode(dir->i_sb, mode);
 565                 if (!inode) {
 566                         dput(dentry);
 567                         goto out_bad;
 568                 }
 569                 inode->i_ino = i;
 570                 if (files[i].i_fop)
 571                         inode->i_fop = files[i].i_fop;
 572                 if (private)
 573                         rpc_inode_setowner(inode, private);
 574                 if (S_ISDIR(mode))
 575                         inc_nlink(dir);
 576                 d_add(dentry, inode);
 577         }
 578         mutex_unlock(&dir->i_mutex);
 579         return 0;
 580 out_bad:
 581         mutex_unlock(&dir->i_mutex);
 582         printk(KERN_WARNING "%s: %s failed to populate directory %s\n",
 583                         __FILE__, __FUNCTION__, parent->d_name.name);
 584         return -ENOMEM;
 585 }
 586
 587 static int
 588 __rpc_mkdir(struct inode *dir, struct dentry *dentry)
 589 {
 590         struct inode *inode;
 591
 592         inode = rpc_get_inode(dir->i_sb, S_IFDIR | S_IRUGO | S_IXUGO);
 593         if (!inode)
 594                 goto out_err;
 595         inode->i_ino = iunique(dir->i_sb, 100);
 596         d_instantiate(dentry, inode);
 597         inc_nlink(dir);
 598         inode_dir_notify(dir, DN_CREATE);
 599         return 0;
 600 out_err:
 601         printk(KERN_WARNING "%s: %s failed to allocate inode for dentry %s\n",
 602                         __FILE__, __FUNCTION__, dentry->d_name.name);
 603         return -ENOMEM;
 604 }
 605
 606 static int
 607 __rpc_rmdir(struct inode *dir, struct dentry *dentry)
 608 {
 609         int error;
 610
 611         shrink_dcache_parent(dentry);
 612         if (d_unhashed(dentry))
 613                 return 0;
 614         if ((error = simple_rmdir(dir, dentry)) != 0)
 615                 return error;
 616         if (!error) {
 617                 inode_dir_notify(dir, DN_DELETE);
 618                 d_drop(dentry);
 619         }
 620         return 0;
 621 }
 622
 623 static struct dentry *
 624 rpc_lookup_create(struct dentry *parent, const char *name, int len)
 625 {
 626         struct inode *dir = parent->d_inode;
 627         struct dentry *dentry;
 628
 629         mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
 630         dentry = lookup_one_len(name, parent, len);
 631         if (IS_ERR(dentry))
 632                 goto out_err;
 633         if (dentry->d_inode) {
 634                 dput(dentry);
 635                 dentry = ERR_PTR(-EEXIST);
 636                 goto out_err;
 637         }
 638         return dentry;
 639 out_err:
 640         mutex_unlock(&dir->i_mutex);
 641         return dentry;
 642 }
 643
 644 static struct dentry *
 645 rpc_lookup_negative(char *path, struct nameidata *nd)
 646 {
 647         struct dentry *dentry;
 648         int error;
 649
 650         if ((error = rpc_lookup_parent(path, nd)) != 0)
 651                 return ERR_PTR(error);
 652         dentry = rpc_lookup_create(nd->dentry, nd->last.name, nd->last.len);
 653         if (IS_ERR(dentry))
 654                 rpc_release_path(nd);
 655         return dentry;
 656 }
 657
 658
 659 struct dentry *
 660 rpc_mkdir(char *path, struct rpc_clnt *rpc_client)
 661 {
 662         struct nameidata nd;
 663         struct dentry *dentry;
 664         struct inode *dir;
 665         int error;
 666
 667         dentry = rpc_lookup_negative(path, &nd);
 668         if (IS_ERR(dentry))
 669                 return dentry;
 670         dir = nd.dentry->d_inode;
 671         if ((error = __rpc_mkdir(dir, dentry)) != 0)
 672                 goto err_dput;
 673         RPC_I(dentry->d_inode)->private = rpc_client;
 674         error = rpc_populate(dentry, authfiles,
 675                         RPCAUTH_info, RPCAUTH_EOF);
 676         if (error)
 677                 goto err_depopulate;
 678         dget(dentry);
 679 out:
 680         mutex_unlock(&dir->i_mutex);
 681         rpc_release_path(&nd);
 682         return dentry;
 683 err_depopulate:
 684         rpc_depopulate(dentry);
 685         __rpc_rmdir(dir, dentry);
 686 err_dput:
 687         dput(dentry);
 688         printk(KERN_WARNING "%s: %s() failed to create directory %s (errno = %d)\n",
 689                         __FILE__, __FUNCTION__, path, error);
 690         dentry = ERR_PTR(error);
 691         goto out;
 692 }
 693
 694 int
 695 rpc_rmdir(struct dentry *dentry)
 696 {
 697         struct dentry *parent;
 698         struct inode *dir;
 699         int error;
 700
 701         parent = dget_parent(dentry);
 702         dir = parent->d_inode;
 703         mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
 704         rpc_depopulate(dentry);
 705         error = __rpc_rmdir(dir, dentry);
 706         dput(dentry);
 707         mutex_unlock(&dir->i_mutex);
 708         dput(parent);
 709         return error;
 710 }
 711
 712 struct dentry *
 713 rpc_mkpipe(struct dentry *parent, const char *name, void *private, struct rpc_pipe_ops *ops, int flags)
 714 {
 715         struct dentry *dentry;
 716         struct inode *dir, *inode;
 717         struct rpc_inode *rpci;
 718
 719         dentry = rpc_lookup_create(parent, name, strlen(name));
 720         if (IS_ERR(dentry))
 721                 return dentry;
 722         dir = parent->d_inode;
 723         inode = rpc_get_inode(dir->i_sb, S_IFIFO | S_IRUSR | S_IWUSR);
 724         if (!inode)
 725                 goto err_dput;
 726         inode->i_ino = iunique(dir->i_sb, 100);
 727         inode->i_fop = &rpc_pipe_fops;
 728         d_instantiate(dentry, inode);
 729         rpci = RPC_I(inode);
 730         rpci->private = private;
 731         rpci->flags = flags;
 732         rpci->ops = ops;
 733         inode_dir_notify(dir, DN_CREATE);
 734         dget(dentry);
 735 out:
 736         mutex_unlock(&dir->i_mutex);
 737         return dentry;
 738 err_dput:
 739         dput(dentry);
 740         dentry = ERR_PTR(-ENOMEM);
 741         printk(KERN_WARNING "%s: %s() failed to create pipe %s/%s (errno = %d)\n",
 742                         __FILE__, __FUNCTION__, parent->d_name.name, name,
 743                         -ENOMEM);
 744         goto out;
 745 }
 746
 747 int
 748 rpc_unlink(struct dentry *dentry)
 749 {
 750         struct dentry *parent;
 751         struct inode *dir;
 752         int error = 0;
 753
 754         parent = dget_parent(dentry);
 755         dir = parent->d_inode;
 756         mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
 757         if (!d_unhashed(dentry)) {
 758                 d_drop(dentry);
 759                 if (dentry->d_inode) {
 760                         rpc_close_pipes(dentry->d_inode);
 761                         error = simple_unlink(dir, dentry);
 762                 }
 763                 inode_dir_notify(dir, DN_DELETE);
 764         }
 765         dput(dentry);
 766         mutex_unlock(&dir->i_mutex);
 767         dput(parent);
 768         return error;
 769 }
 770
 771 /*
 772  * populate the filesystem
 773  */
 774 static struct super_operations s_ops = {
 775         .alloc_inode    = rpc_alloc_inode,
 776         .destroy_inode  = rpc_destroy_inode,
 777         .statfs         = simple_statfs,
 778 };
 779
 780 #define RPCAUTH_GSSMAGIC 0x67596969
 781
 782 static int
 783 rpc_fill_super(struct super_block *sb, void *data, int silent)
 784 {
 785         struct inode *inode;
 786         struct dentry *root;
 787
 788         sb->s_blocksize = PAGE_CACHE_SIZE;
 789         sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
 790         sb->s_magic = RPCAUTH_GSSMAGIC;
 791         sb->s_op = &s_ops;
 792         sb->s_time_gran = 1;
 793
 794         inode = rpc_get_inode(sb, S_IFDIR | 0755);
 795         if (!inode)
 796                 return -ENOMEM;
 797         root = d_alloc_root(inode);
 798         if (!root) {
 799                 iput(inode);
 800                 return -ENOMEM;
 801         }
 802         if (rpc_populate(root, files, RPCAUTH_Root + 1, RPCAUTH_RootEOF))
 803                 goto out;
 804         sb->s_root = root;
 805         return 0;
 806 out:
 807         d_genocide(root);
 808         dput(root);
 809         return -ENOMEM;
 810 }
 811
 812 static int
 813 rpc_get_sb(struct file_system_type *fs_type,
 814                 int flags, const char *dev_name, void *data, struct vfsmount *mnt)
 815 {
 816         return get_sb_single(fs_type, flags, data, rpc_fill_super, mnt);
 817 }
 818
 819 static struct file_system_type rpc_pipe_fs_type = {
 820         .owner          = THIS_MODULE,
 821         .name           = "rpc_pipefs",
 822         .get_sb         = rpc_get_sb,
 823         .kill_sb        = kill_litter_super,
 824 };
 825
 826 static void
 827 init_once(void * foo, struct kmem_cache * cachep, unsigned long flags)
 828 {
 829         struct rpc_inode *rpci = (struct rpc_inode *) foo;
 830
 831         inode_init_once(&rpci->vfs_inode);
 832         rpci->private = NULL;
 833         rpci->nreaders = 0;
 834         rpci->nwriters = 0;
 835         INIT_LIST_HEAD(&rpci->in_upcall);
 836         INIT_LIST_HEAD(&rpci->pipe);
 837         rpci->pipelen = 0;
 838         init_waitqueue_head(&rpci->waitq);
 839         INIT_DELAYED_WORK(&rpci->queue_timeout,
 840                             rpc_timeout_upcall_queue);
 841         rpci->ops = NULL;
 842 }
 843
 844 int register_rpc_pipefs(void)
 845 {
 846         int err;
 847
 848         rpc_inode_cachep = kmem_cache_create("rpc_inode_cache",
 849                                 sizeof(struct rpc_inode),
 850                                 0, (SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT|
 851                                                 SLAB_MEM_SPREAD),
 852                                 init_once, NULL);
 853         if (!rpc_inode_cachep)
 854                 return -ENOMEM;
 855         err = register_filesystem(&rpc_pipe_fs_type);
 856         if (err) {
 857                 kmem_cache_destroy(rpc_inode_cachep);
 858                 return err;
 859         }
 860
 861         return 0;
 862 }
 863
 864 void unregister_rpc_pipefs(void)
 865 {
 866         kmem_cache_destroy(rpc_inode_cachep);
 867         unregister_filesystem(&rpc_pipe_fs_type);
 868 }