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 rpc_purge_list(struct rpc_inode *rpci, struct list_head *head,
  42                 void (*destroy_msg)(struct rpc_pipe_msg *), int err)
  43 {
  44         struct rpc_pipe_msg *msg;
  45
  46         if (list_empty(head))
  47                 return;
  48         do {
  49                 msg = list_entry(head->next, struct rpc_pipe_msg, list);
  50                 list_del(&msg->list);
  51                 msg->errno = err;
  52                 destroy_msg(msg);
  53         } while (!list_empty(head));
  54         wake_up(&rpci->waitq);
  55 }
  56
  57 static void
  58 rpc_timeout_upcall_queue(void *data)
  59 {
  60         LIST_HEAD(free_list);
  61         struct rpc_inode *rpci = (struct rpc_inode *)data;
  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, SLAB_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_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_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_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_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 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: %u.%u.%u.%u\n",
 332                         NIPQUAD(clnt->cl_xprt->addr.sin_addr.s_addr));
 333         seq_printf(m, "protocol: %s\n",
 334                         clnt->cl_xprt->prot == IPPROTO_UDP ? "udp" : "tcp");
 335         return 0;
 336 }
 337
 338 static int
 339 rpc_info_open(struct inode *inode, struct file *file)
 340 {
 341         struct rpc_clnt *clnt;
 342         int ret = single_open(file, rpc_show_info, NULL);
 343
 344         if (!ret) {
 345                 struct seq_file *m = file->private_data;
 346                 mutex_lock(&inode->i_mutex);
 347                 clnt = RPC_I(inode)->private;
 348                 if (clnt) {
 349                         atomic_inc(&clnt->cl_users);
 350                         m->private = clnt;
 351                 } else {
 352                         single_release(inode, file);
 353                         ret = -EINVAL;
 354                 }
 355                 mutex_unlock(&inode->i_mutex);
 356         }
 357         return ret;
 358 }
 359
 360 static int
 361 rpc_info_release(struct inode *inode, struct file *file)
 362 {
 363         struct seq_file *m = file->private_data;
 364         struct rpc_clnt *clnt = (struct rpc_clnt *)m->private;
 365
 366         if (clnt)
 367                 rpc_release_client(clnt);
 368         return single_release(inode, file);
 369 }
 370
 371 static struct file_operations rpc_info_operations = {
 372         .owner          = THIS_MODULE,
 373         .open           = rpc_info_open,
 374         .read           = seq_read,
 375         .llseek         = seq_lseek,
 376         .release        = rpc_info_release,
 377 };
 378
 379
 380 /*
 381  * We have a single directory with 1 node in it.
 382  */
 383 enum {
 384         RPCAUTH_Root = 1,
 385         RPCAUTH_lockd,
 386         RPCAUTH_mount,
 387         RPCAUTH_nfs,
 388         RPCAUTH_portmap,
 389         RPCAUTH_statd,
 390         RPCAUTH_RootEOF
 391 };
 392
 393 /*
 394  * Description of fs contents.
 395  */
 396 struct rpc_filelist {
 397         char *name;
 398         const struct file_operations *i_fop;
 399         int mode;
 400 };
 401
 402 static struct rpc_filelist files[] = {
 403         [RPCAUTH_lockd] = {
 404                 .name = "lockd",
 405                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
 406         },
 407         [RPCAUTH_mount] = {
 408                 .name = "mount",
 409                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
 410         },
 411         [RPCAUTH_nfs] = {
 412                 .name = "nfs",
 413                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
 414         },
 415         [RPCAUTH_portmap] = {
 416                 .name = "portmap",
 417                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
 418         },
 419         [RPCAUTH_statd] = {
 420                 .name = "statd",
 421                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
 422         },
 423 };
 424
 425 enum {
 426         RPCAUTH_info = 2,
 427         RPCAUTH_EOF
 428 };
 429
 430 static struct rpc_filelist authfiles[] = {
 431         [RPCAUTH_info] = {
 432                 .name = "info",
 433                 .i_fop = &rpc_info_operations,
 434                 .mode = S_IFREG | S_IRUSR,
 435         },
 436 };
 437
 438 struct vfsmount *rpc_get_mount(void)
 439 {
 440         int err;
 441
 442         err = simple_pin_fs("rpc_pipefs", &rpc_mount, &rpc_mount_count);
 443         if (err != 0)
 444                 return ERR_PTR(err);
 445         return rpc_mount;
 446 }
 447
 448 void rpc_put_mount(void)
 449 {
 450         simple_release_fs(&rpc_mount, &rpc_mount_count);
 451 }
 452
 453 static int
 454 rpc_lookup_parent(char *path, struct nameidata *nd)
 455 {
 456         if (path[0] == '\0')
 457                 return -ENOENT;
 458         nd->mnt = rpc_get_mount();
 459         if (IS_ERR(nd->mnt)) {
 460                 printk(KERN_WARNING "%s: %s failed to mount "
 461                                "pseudofilesystem \n", __FILE__, __FUNCTION__);
 462                 return PTR_ERR(nd->mnt);
 463         }
 464         mntget(nd->mnt);
 465         nd->dentry = dget(rpc_mount->mnt_root);
 466         nd->last_type = LAST_ROOT;
 467         nd->flags = LOOKUP_PARENT;
 468         nd->depth = 0;
 469
 470         if (path_walk(path, nd)) {
 471                 printk(KERN_WARNING "%s: %s failed to find path %s\n",
 472                                 __FILE__, __FUNCTION__, path);
 473                 rpc_put_mount();
 474                 return -ENOENT;
 475         }
 476         return 0;
 477 }
 478
 479 static void
 480 rpc_release_path(struct nameidata *nd)
 481 {
 482         path_release(nd);
 483         rpc_put_mount();
 484 }
 485
 486 static struct inode *
 487 rpc_get_inode(struct super_block *sb, int mode)
 488 {
 489         struct inode *inode = new_inode(sb);
 490         if (!inode)
 491                 return NULL;
 492         inode->i_mode = mode;
 493         inode->i_uid = inode->i_gid = 0;
 494         inode->i_blksize = PAGE_CACHE_SIZE;
 495         inode->i_blocks = 0;
 496         inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
 497         switch(mode & S_IFMT) {
 498                 case S_IFDIR:
 499                         inode->i_fop = &simple_dir_operations;
 500                         inode->i_op = &simple_dir_inode_operations;
 501                         inode->i_nlink++;
 502                 default:
 503                         break;
 504         }
 505         return inode;
 506 }
 507
 508 /*
 509  * FIXME: This probably has races.
 510  */
 511 static void
 512 rpc_depopulate(struct dentry *parent)
 513 {
 514         struct inode *dir = parent->d_inode;
 515         struct list_head *pos, *next;
 516         struct dentry *dentry, *dvec[10];
 517         int n = 0;
 518
 519         mutex_lock(&dir->i_mutex);
 520 repeat:
 521         spin_lock(&dcache_lock);
 522         list_for_each_safe(pos, next, &parent->d_subdirs) {
 523                 dentry = list_entry(pos, struct dentry, d_u.d_child);
 524                 spin_lock(&dentry->d_lock);
 525                 if (!d_unhashed(dentry)) {
 526                         dget_locked(dentry);
 527                         __d_drop(dentry);
 528                         spin_unlock(&dentry->d_lock);
 529                         dvec[n++] = dentry;
 530                         if (n == ARRAY_SIZE(dvec))
 531                                 break;
 532                 } else
 533                         spin_unlock(&dentry->d_lock);
 534         }
 535         spin_unlock(&dcache_lock);
 536         if (n) {
 537                 do {
 538                         dentry = dvec[--n];
 539                         if (dentry->d_inode) {
 540                                 rpc_close_pipes(dentry->d_inode);
 541                                 simple_unlink(dir, dentry);
 542                         }
 543                         dput(dentry);
 544                 } while (n);
 545                 goto repeat;
 546         }
 547         mutex_unlock(&dir->i_mutex);
 548 }
 549
 550 static int
 551 rpc_populate(struct dentry *parent,
 552                 struct rpc_filelist *files,
 553                 int start, int eof)
 554 {
 555         struct inode *inode, *dir = parent->d_inode;
 556         void *private = RPC_I(dir)->private;
 557         struct dentry *dentry;
 558         int mode, i;
 559
 560         mutex_lock(&dir->i_mutex);
 561         for (i = start; i < eof; i++) {
 562                 dentry = d_alloc_name(parent, files[i].name);
 563                 if (!dentry)
 564                         goto out_bad;
 565                 mode = files[i].mode;
 566                 inode = rpc_get_inode(dir->i_sb, mode);
 567                 if (!inode) {
 568                         dput(dentry);
 569                         goto out_bad;
 570                 }
 571                 inode->i_ino = i;
 572                 if (files[i].i_fop)
 573                         inode->i_fop = files[i].i_fop;
 574                 if (private)
 575                         rpc_inode_setowner(inode, private);
 576                 if (S_ISDIR(mode))
 577                         dir->i_nlink++;
 578                 d_add(dentry, inode);
 579         }
 580         mutex_unlock(&dir->i_mutex);
 581         return 0;
 582 out_bad:
 583         mutex_unlock(&dir->i_mutex);
 584         printk(KERN_WARNING "%s: %s failed to populate directory %s\n",
 585                         __FILE__, __FUNCTION__, parent->d_name.name);
 586         return -ENOMEM;
 587 }
 588
 589 static int
 590 __rpc_mkdir(struct inode *dir, struct dentry *dentry)
 591 {
 592         struct inode *inode;
 593
 594         inode = rpc_get_inode(dir->i_sb, S_IFDIR | S_IRUSR | S_IXUSR);
 595         if (!inode)
 596                 goto out_err;
 597         inode->i_ino = iunique(dir->i_sb, 100);
 598         d_instantiate(dentry, inode);
 599         dir->i_nlink++;
 600         inode_dir_notify(dir, DN_CREATE);
 601         return 0;
 602 out_err:
 603         printk(KERN_WARNING "%s: %s failed to allocate inode for dentry %s\n",
 604                         __FILE__, __FUNCTION__, dentry->d_name.name);
 605         return -ENOMEM;
 606 }
 607
 608 static int
 609 __rpc_rmdir(struct inode *dir, struct dentry *dentry)
 610 {
 611         int error;
 612
 613         shrink_dcache_parent(dentry);
 614         if (dentry->d_inode)
 615                 rpc_close_pipes(dentry->d_inode);
 616         if ((error = simple_rmdir(dir, dentry)) != 0)
 617                 return error;
 618         if (!error) {
 619                 inode_dir_notify(dir, DN_DELETE);
 620                 d_drop(dentry);
 621         }
 622         return 0;
 623 }
 624
 625 static struct dentry *
 626 rpc_lookup_negative(char *path, struct nameidata *nd)
 627 {
 628         struct dentry *dentry;
 629         struct inode *dir;
 630         int error;
 631
 632         if ((error = rpc_lookup_parent(path, nd)) != 0)
 633                 return ERR_PTR(error);
 634         dir = nd->dentry->d_inode;
 635         mutex_lock(&dir->i_mutex);
 636         dentry = lookup_one_len(nd->last.name, nd->dentry, nd->last.len);
 637         if (IS_ERR(dentry))
 638                 goto out_err;
 639         if (dentry->d_inode) {
 640                 dput(dentry);
 641                 dentry = ERR_PTR(-EEXIST);
 642                 goto out_err;
 643         }
 644         return dentry;
 645 out_err:
 646         mutex_unlock(&dir->i_mutex);
 647         rpc_release_path(nd);
 648         return dentry;
 649 }
 650
 651
 652 struct dentry *
 653 rpc_mkdir(char *path, struct rpc_clnt *rpc_client)
 654 {
 655         struct nameidata nd;
 656         struct dentry *dentry;
 657         struct inode *dir;
 658         int error;
 659
 660         dentry = rpc_lookup_negative(path, &nd);
 661         if (IS_ERR(dentry))
 662                 return dentry;
 663         dir = nd.dentry->d_inode;
 664         if ((error = __rpc_mkdir(dir, dentry)) != 0)
 665                 goto err_dput;
 666         RPC_I(dentry->d_inode)->private = rpc_client;
 667         error = rpc_populate(dentry, authfiles,
 668                         RPCAUTH_info, RPCAUTH_EOF);
 669         if (error)
 670                 goto err_depopulate;
 671 out:
 672         mutex_unlock(&dir->i_mutex);
 673         rpc_release_path(&nd);
 674         return dget(dentry);
 675 err_depopulate:
 676         rpc_depopulate(dentry);
 677         __rpc_rmdir(dir, dentry);
 678 err_dput:
 679         dput(dentry);
 680         printk(KERN_WARNING "%s: %s() failed to create directory %s (errno = %d)\n",
 681                         __FILE__, __FUNCTION__, path, error);
 682         dentry = ERR_PTR(error);
 683         goto out;
 684 }
 685
 686 int
 687 rpc_rmdir(char *path)
 688 {
 689         struct nameidata nd;
 690         struct dentry *dentry;
 691         struct inode *dir;
 692         int error;
 693
 694         if ((error = rpc_lookup_parent(path, &nd)) != 0)
 695                 return error;
 696         dir = nd.dentry->d_inode;
 697         mutex_lock(&dir->i_mutex);
 698         dentry = lookup_one_len(nd.last.name, nd.dentry, nd.last.len);
 699         if (IS_ERR(dentry)) {
 700                 error = PTR_ERR(dentry);
 701                 goto out_release;
 702         }
 703         rpc_depopulate(dentry);
 704         error = __rpc_rmdir(dir, dentry);
 705         dput(dentry);
 706 out_release:
 707         mutex_unlock(&dir->i_mutex);
 708         rpc_release_path(&nd);
 709         return error;
 710 }
 711
 712 struct dentry *
 713 rpc_mkpipe(char *path, void *private, struct rpc_pipe_ops *ops, int flags)
 714 {
 715         struct nameidata nd;
 716         struct dentry *dentry;
 717         struct inode *dir, *inode;
 718         struct rpc_inode *rpci;
 719
 720         dentry = rpc_lookup_negative(path, &nd);
 721         if (IS_ERR(dentry))
 722                 return dentry;
 723         dir = nd.dentry->d_inode;
 724         inode = rpc_get_inode(dir->i_sb, S_IFSOCK | S_IRUSR | S_IWUSR);
 725         if (!inode)
 726                 goto err_dput;
 727         inode->i_ino = iunique(dir->i_sb, 100);
 728         inode->i_fop = &rpc_pipe_fops;
 729         d_instantiate(dentry, inode);
 730         rpci = RPC_I(inode);
 731         rpci->private = private;
 732         rpci->flags = flags;
 733         rpci->ops = ops;
 734         inode_dir_notify(dir, DN_CREATE);
 735 out:
 736         mutex_unlock(&dir->i_mutex);
 737         rpc_release_path(&nd);
 738         return dget(dentry);
 739 err_dput:
 740         dput(dentry);
 741         dentry = ERR_PTR(-ENOMEM);
 742         printk(KERN_WARNING "%s: %s() failed to create pipe %s (errno = %d)\n",
 743                         __FILE__, __FUNCTION__, path, -ENOMEM);
 744         goto out;
 745 }
 746
 747 int
 748 rpc_unlink(char *path)
 749 {
 750         struct nameidata nd;
 751         struct dentry *dentry;
 752         struct inode *dir;
 753         int error;
 754
 755         if ((error = rpc_lookup_parent(path, &nd)) != 0)
 756                 return error;
 757         dir = nd.dentry->d_inode;
 758         mutex_lock(&dir->i_mutex);
 759         dentry = lookup_one_len(nd.last.name, nd.dentry, nd.last.len);
 760         if (IS_ERR(dentry)) {
 761                 error = PTR_ERR(dentry);
 762                 goto out_release;
 763         }
 764         d_drop(dentry);
 765         if (dentry->d_inode) {
 766                 rpc_close_pipes(dentry->d_inode);
 767                 error = simple_unlink(dir, dentry);
 768         }
 769         dput(dentry);
 770         inode_dir_notify(dir, DN_DELETE);
 771 out_release:
 772         mutex_unlock(&dir->i_mutex);
 773         rpc_release_path(&nd);
 774         return error;
 775 }
 776
 777 /*
 778  * populate the filesystem
 779  */
 780 static struct super_operations s_ops = {
 781         .alloc_inode    = rpc_alloc_inode,
 782         .destroy_inode  = rpc_destroy_inode,
 783         .statfs         = simple_statfs,
 784 };
 785
 786 #define RPCAUTH_GSSMAGIC 0x67596969
 787
 788 static int
 789 rpc_fill_super(struct super_block *sb, void *data, int silent)
 790 {
 791         struct inode *inode;
 792         struct dentry *root;
 793
 794         sb->s_blocksize = PAGE_CACHE_SIZE;
 795         sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
 796         sb->s_magic = RPCAUTH_GSSMAGIC;
 797         sb->s_op = &s_ops;
 798         sb->s_time_gran = 1;
 799
 800         inode = rpc_get_inode(sb, S_IFDIR | 0755);
 801         if (!inode)
 802                 return -ENOMEM;
 803         root = d_alloc_root(inode);
 804         if (!root) {
 805                 iput(inode);
 806                 return -ENOMEM;
 807         }
 808         if (rpc_populate(root, files, RPCAUTH_Root + 1, RPCAUTH_RootEOF))
 809                 goto out;
 810         sb->s_root = root;
 811         return 0;
 812 out:
 813         d_genocide(root);
 814         dput(root);
 815         return -ENOMEM;
 816 }
 817
 818 static struct super_block *
 819 rpc_get_sb(struct file_system_type *fs_type,
 820                 int flags, const char *dev_name, void *data)
 821 {
 822         return get_sb_single(fs_type, flags, data, rpc_fill_super);
 823 }
 824
 825 static struct file_system_type rpc_pipe_fs_type = {
 826         .owner          = THIS_MODULE,
 827         .name           = "rpc_pipefs",
 828         .get_sb         = rpc_get_sb,
 829         .kill_sb        = kill_litter_super,
 830 };
 831
 832 static void
 833 init_once(void * foo, kmem_cache_t * cachep, unsigned long flags)
 834 {
 835         struct rpc_inode *rpci = (struct rpc_inode *) foo;
 836
 837         if ((flags & (SLAB_CTOR_VERIFY|SLAB_CTOR_CONSTRUCTOR)) ==
 838             SLAB_CTOR_CONSTRUCTOR) {
 839                 inode_init_once(&rpci->vfs_inode);
 840                 rpci->private = NULL;
 841                 rpci->nreaders = 0;
 842                 rpci->nwriters = 0;
 843                 INIT_LIST_HEAD(&rpci->in_upcall);
 844                 INIT_LIST_HEAD(&rpci->pipe);
 845                 rpci->pipelen = 0;
 846                 init_waitqueue_head(&rpci->waitq);
 847                 INIT_WORK(&rpci->queue_timeout, rpc_timeout_upcall_queue, rpci);
 848                 rpci->ops = NULL;
 849         }
 850 }
 851
 852 int register_rpc_pipefs(void)
 853 {
 854         rpc_inode_cachep = kmem_cache_create("rpc_inode_cache",
 855                                 sizeof(struct rpc_inode),
 856                                 0, (SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT|
 857                                                 SLAB_MEM_SPREAD),
 858                                 init_once, NULL);
 859         if (!rpc_inode_cachep)
 860                 return -ENOMEM;
 861         register_filesystem(&rpc_pipe_fs_type);
 862         return 0;
 863 }
 864
 865 void unregister_rpc_pipefs(void)
 866 {
 867         if (kmem_cache_destroy(rpc_inode_cachep))
 868                 printk(KERN_WARNING "RPC: unable to free inode cache\n");
 869         unregister_filesystem(&rpc_pipe_fs_type);
 870 }