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