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 kmem_cache_t *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(void *data)
  58 {
  59         LIST_HEAD(free_list);
  60         struct rpc_inode *rpci = (struct rpc_inode *)data;
  61         struct inode *inode = &rpci->vfs_inode;
  62         void (*destroy_msg)(struct rpc_pipe_msg *);
  63
  64         spin_lock(&inode->i_lock);
  65         if (rpci->ops == NULL) {
  66                 spin_unlock(&inode->i_lock);
  67                 return;
  68         }
  69         destroy_msg = rpci->ops->destroy_msg;
  70         if (rpci->nreaders == 0) {
  71                 list_splice_init(&rpci->pipe, &free_list);
  72                 rpci->pipelen = 0;
  73         }
  74         spin_unlock(&inode->i_lock);
  75         rpc_purge_list(rpci, &free_list, destroy_msg, -ETIMEDOUT);
  76 }
  77
  78 int
  79 rpc_queue_upcall(struct inode *inode, struct rpc_pipe_msg *msg)
  80 {
  81         struct rpc_inode *rpci = RPC_I(inode);
  82         int res = -EPIPE;
  83
  84         spin_lock(&inode->i_lock);
  85         if (rpci->ops == NULL)
  86                 goto out;
  87         if (rpci->nreaders) {
  88                 list_add_tail(&msg->list, &rpci->pipe);
  89                 rpci->pipelen += msg->len;
  90                 res = 0;
  91         } else if (rpci->flags & RPC_PIPE_WAIT_FOR_OPEN) {
  92                 if (list_empty(&rpci->pipe))
  93                         queue_delayed_work(rpciod_workqueue,
  94                                         &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_workqueue(rpciod_workqueue);
 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         const 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 struct vfsmount *rpc_get_mount(void)
 438 {
 439         int err;
 440
 441         err = simple_pin_fs(&rpc_pipe_fs_type, &rpc_mount, &rpc_mount_count);
 442         if (err != 0)
 443                 return ERR_PTR(err);
 444         return rpc_mount;
 445 }
 446
 447 void rpc_put_mount(void)
 448 {
 449         simple_release_fs(&rpc_mount, &rpc_mount_count);
 450 }
 451
 452 static int
 453 rpc_lookup_parent(char *path, struct nameidata *nd)
 454 {
 455         if (path[0] == '\0')
 456                 return -ENOENT;
 457         nd->mnt = rpc_get_mount();
 458         if (IS_ERR(nd->mnt)) {
 459                 printk(KERN_WARNING "%s: %s failed to mount "
 460                                "pseudofilesystem \n", __FILE__, __FUNCTION__);
 461                 return PTR_ERR(nd->mnt);
 462         }
 463         mntget(nd->mnt);
 464         nd->dentry = dget(rpc_mount->mnt_root);
 465         nd->last_type = LAST_ROOT;
 466         nd->flags = LOOKUP_PARENT;
 467         nd->depth = 0;
 468
 469         if (path_walk(path, nd)) {
 470                 printk(KERN_WARNING "%s: %s failed to find path %s\n",
 471                                 __FILE__, __FUNCTION__, path);
 472                 rpc_put_mount();
 473                 return -ENOENT;
 474         }
 475         return 0;
 476 }
 477
 478 static void
 479 rpc_release_path(struct nameidata *nd)
 480 {
 481         path_release(nd);
 482         rpc_put_mount();
 483 }
 484
 485 static struct inode *
 486 rpc_get_inode(struct super_block *sb, int mode)
 487 {
 488         struct inode *inode = new_inode(sb);
 489         if (!inode)
 490                 return NULL;
 491         inode->i_mode = mode;
 492         inode->i_uid = inode->i_gid = 0;
 493         inode->i_blocks = 0;
 494         inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
 495         switch(mode & S_IFMT) {
 496                 case S_IFDIR:
 497                         inode->i_fop = &simple_dir_operations;
 498                         inode->i_op = &simple_dir_inode_operations;
 499                         inode->i_nlink++;
 500                 default:
 501                         break;
 502         }
 503         return inode;
 504 }
 505
 506 /*
 507  * FIXME: This probably has races.
 508  */
 509 static void
 510 rpc_depopulate(struct dentry *parent)
 511 {
 512         struct inode *dir = parent->d_inode;
 513         struct list_head *pos, *next;
 514         struct dentry *dentry, *dvec[10];
 515         int n = 0;
 516
 517         mutex_lock_nested(&dir->i_mutex, I_MUTEX_CHILD);
 518 repeat:
 519         spin_lock(&dcache_lock);
 520         list_for_each_safe(pos, next, &parent->d_subdirs) {
 521                 dentry = list_entry(pos, struct dentry, d_u.d_child);
 522                 spin_lock(&dentry->d_lock);
 523                 if (!d_unhashed(dentry)) {
 524                         dget_locked(dentry);
 525                         __d_drop(dentry);
 526                         spin_unlock(&dentry->d_lock);
 527                         dvec[n++] = dentry;
 528                         if (n == ARRAY_SIZE(dvec))
 529                                 break;
 530                 } else
 531                         spin_unlock(&dentry->d_lock);
 532         }
 533         spin_unlock(&dcache_lock);
 534         if (n) {
 535                 do {
 536                         dentry = dvec[--n];
 537                         if (dentry->d_inode) {
 538                                 rpc_close_pipes(dentry->d_inode);
 539                                 simple_unlink(dir, dentry);
 540                         }
 541                         inode_dir_notify(dir, DN_DELETE);
 542                         dput(dentry);
 543                 } while (n);
 544                 goto repeat;
 545         }
 546         mutex_unlock(&dir->i_mutex);
 547 }
 548
 549 static int
 550 rpc_populate(struct dentry *parent,
 551                 struct rpc_filelist *files,
 552                 int start, int eof)
 553 {
 554         struct inode *inode, *dir = parent->d_inode;
 555         void *private = RPC_I(dir)->private;
 556         struct dentry *dentry;
 557         int mode, i;
 558
 559         mutex_lock(&dir->i_mutex);
 560         for (i = start; i < eof; i++) {
 561                 dentry = d_alloc_name(parent, files[i].name);
 562                 if (!dentry)
 563                         goto out_bad;
 564                 mode = files[i].mode;
 565                 inode = rpc_get_inode(dir->i_sb, mode);
 566                 if (!inode) {
 567                         dput(dentry);
 568                         goto out_bad;
 569                 }
 570                 inode->i_ino = i;
 571                 if (files[i].i_fop)
 572                         inode->i_fop = files[i].i_fop;
 573                 if (private)
 574                         rpc_inode_setowner(inode, private);
 575                 if (S_ISDIR(mode))
 576                         dir->i_nlink++;
 577                 d_add(dentry, inode);
 578         }
 579         mutex_unlock(&dir->i_mutex);
 580         return 0;
 581 out_bad:
 582         mutex_unlock(&dir->i_mutex);
 583         printk(KERN_WARNING "%s: %s failed to populate directory %s\n",
 584                         __FILE__, __FUNCTION__, parent->d_name.name);
 585         return -ENOMEM;
 586 }
 587
 588 static int
 589 __rpc_mkdir(struct inode *dir, struct dentry *dentry)
 590 {
 591         struct inode *inode;
 592
 593         inode = rpc_get_inode(dir->i_sb, S_IFDIR | S_IRUSR | S_IXUSR);
 594         if (!inode)
 595                 goto out_err;
 596         inode->i_ino = iunique(dir->i_sb, 100);
 597         d_instantiate(dentry, inode);
 598         dir->i_nlink++;
 599         inode_dir_notify(dir, DN_CREATE);
 600         return 0;
 601 out_err:
 602         printk(KERN_WARNING "%s: %s failed to allocate inode for dentry %s\n",
 603                         __FILE__, __FUNCTION__, dentry->d_name.name);
 604         return -ENOMEM;
 605 }
 606
 607 static int
 608 __rpc_rmdir(struct inode *dir, struct dentry *dentry)
 609 {
 610         int error;
 611
 612         shrink_dcache_parent(dentry);
 613         if (d_unhashed(dentry))
 614                 return 0;
 615         if ((error = simple_rmdir(dir, dentry)) != 0)
 616                 return error;
 617         if (!error) {
 618                 inode_dir_notify(dir, DN_DELETE);
 619                 d_drop(dentry);
 620         }
 621         return 0;
 622 }
 623
 624 static struct dentry *
 625 rpc_lookup_negative(char *path, struct nameidata *nd)
 626 {
 627         struct dentry *dentry;
 628         struct inode *dir;
 629         int error;
 630
 631         if ((error = rpc_lookup_parent(path, nd)) != 0)
 632                 return ERR_PTR(error);
 633         dir = nd->dentry->d_inode;
 634         mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
 635         dentry = lookup_one_len(nd->last.name, nd->dentry, nd->last.len);
 636         if (IS_ERR(dentry))
 637                 goto out_err;
 638         if (dentry->d_inode) {
 639                 dput(dentry);
 640                 dentry = ERR_PTR(-EEXIST);
 641                 goto out_err;
 642         }
 643         return dentry;
 644 out_err:
 645         mutex_unlock(&dir->i_mutex);
 646         rpc_release_path(nd);
 647         return dentry;
 648 }
 649
 650
 651 struct dentry *
 652 rpc_mkdir(char *path, struct rpc_clnt *rpc_client)
 653 {
 654         struct nameidata nd;
 655         struct dentry *dentry;
 656         struct inode *dir;
 657         int error;
 658
 659         dentry = rpc_lookup_negative(path, &nd);
 660         if (IS_ERR(dentry))
 661                 return dentry;
 662         dir = nd.dentry->d_inode;
 663         if ((error = __rpc_mkdir(dir, dentry)) != 0)
 664                 goto err_dput;
 665         RPC_I(dentry->d_inode)->private = rpc_client;
 666         error = rpc_populate(dentry, authfiles,
 667                         RPCAUTH_info, RPCAUTH_EOF);
 668         if (error)
 669                 goto err_depopulate;
 670         dget(dentry);
 671 out:
 672         mutex_unlock(&dir->i_mutex);
 673         rpc_release_path(&nd);
 674         return 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(struct dentry *dentry)
 688 {
 689         struct dentry *parent;
 690         struct inode *dir;
 691         int error;
 692
 693         parent = dget_parent(dentry);
 694         dir = parent->d_inode;
 695         mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
 696         rpc_depopulate(dentry);
 697         error = __rpc_rmdir(dir, dentry);
 698         dput(dentry);
 699         mutex_unlock(&dir->i_mutex);
 700         dput(parent);
 701         return error;
 702 }
 703
 704 struct dentry *
 705 rpc_mkpipe(char *path, void *private, struct rpc_pipe_ops *ops, int flags)
 706 {
 707         struct nameidata nd;
 708         struct dentry *dentry;
 709         struct inode *dir, *inode;
 710         struct rpc_inode *rpci;
 711
 712         dentry = rpc_lookup_negative(path, &nd);
 713         if (IS_ERR(dentry))
 714                 return dentry;
 715         dir = nd.dentry->d_inode;
 716         inode = rpc_get_inode(dir->i_sb, S_IFIFO | S_IRUSR | S_IWUSR);
 717         if (!inode)
 718                 goto err_dput;
 719         inode->i_ino = iunique(dir->i_sb, 100);
 720         inode->i_fop = &rpc_pipe_fops;
 721         d_instantiate(dentry, inode);
 722         rpci = RPC_I(inode);
 723         rpci->private = private;
 724         rpci->flags = flags;
 725         rpci->ops = ops;
 726         inode_dir_notify(dir, DN_CREATE);
 727         dget(dentry);
 728 out:
 729         mutex_unlock(&dir->i_mutex);
 730         rpc_release_path(&nd);
 731         return dentry;
 732 err_dput:
 733         dput(dentry);
 734         dentry = ERR_PTR(-ENOMEM);
 735         printk(KERN_WARNING "%s: %s() failed to create pipe %s (errno = %d)\n",
 736                         __FILE__, __FUNCTION__, path, -ENOMEM);
 737         goto out;
 738 }
 739
 740 int
 741 rpc_unlink(struct dentry *dentry)
 742 {
 743         struct dentry *parent;
 744         struct inode *dir;
 745         int error = 0;
 746
 747         parent = dget_parent(dentry);
 748         dir = parent->d_inode;
 749         mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
 750         if (!d_unhashed(dentry)) {
 751                 d_drop(dentry);
 752                 if (dentry->d_inode) {
 753                         rpc_close_pipes(dentry->d_inode);
 754                         error = simple_unlink(dir, dentry);
 755                 }
 756                 inode_dir_notify(dir, DN_DELETE);
 757         }
 758         dput(dentry);
 759         mutex_unlock(&dir->i_mutex);
 760         dput(parent);
 761         return error;
 762 }
 763
 764 /*
 765  * populate the filesystem
 766  */
 767 static struct super_operations s_ops = {
 768         .alloc_inode    = rpc_alloc_inode,
 769         .destroy_inode  = rpc_destroy_inode,
 770         .statfs         = simple_statfs,
 771 };
 772
 773 #define RPCAUTH_GSSMAGIC 0x67596969
 774
 775 static int
 776 rpc_fill_super(struct super_block *sb, void *data, int silent)
 777 {
 778         struct inode *inode;
 779         struct dentry *root;
 780
 781         sb->s_blocksize = PAGE_CACHE_SIZE;
 782         sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
 783         sb->s_magic = RPCAUTH_GSSMAGIC;
 784         sb->s_op = &s_ops;
 785         sb->s_time_gran = 1;
 786
 787         inode = rpc_get_inode(sb, S_IFDIR | 0755);
 788         if (!inode)
 789                 return -ENOMEM;
 790         root = d_alloc_root(inode);
 791         if (!root) {
 792                 iput(inode);
 793                 return -ENOMEM;
 794         }
 795         if (rpc_populate(root, files, RPCAUTH_Root + 1, RPCAUTH_RootEOF))
 796                 goto out;
 797         sb->s_root = root;
 798         return 0;
 799 out:
 800         d_genocide(root);
 801         dput(root);
 802         return -ENOMEM;
 803 }
 804
 805 static int
 806 rpc_get_sb(struct file_system_type *fs_type,
 807                 int flags, const char *dev_name, void *data, struct vfsmount *mnt)
 808 {
 809         return get_sb_single(fs_type, flags, data, rpc_fill_super, mnt);
 810 }
 811
 812 static struct file_system_type rpc_pipe_fs_type = {
 813         .owner          = THIS_MODULE,
 814         .name           = "rpc_pipefs",
 815         .get_sb         = rpc_get_sb,
 816         .kill_sb        = kill_litter_super,
 817 };
 818
 819 static void
 820 init_once(void * foo, kmem_cache_t * cachep, unsigned long flags)
 821 {
 822         struct rpc_inode *rpci = (struct rpc_inode *) foo;
 823
 824         if ((flags & (SLAB_CTOR_VERIFY|SLAB_CTOR_CONSTRUCTOR)) ==
 825             SLAB_CTOR_CONSTRUCTOR) {
 826                 inode_init_once(&rpci->vfs_inode);
 827                 rpci->private = NULL;
 828                 rpci->nreaders = 0;
 829                 rpci->nwriters = 0;
 830                 INIT_LIST_HEAD(&rpci->in_upcall);
 831                 INIT_LIST_HEAD(&rpci->pipe);
 832                 rpci->pipelen = 0;
 833                 init_waitqueue_head(&rpci->waitq);
 834                 INIT_WORK(&rpci->queue_timeout, rpc_timeout_upcall_queue, rpci);
 835                 rpci->ops = NULL;
 836         }
 837 }
 838
 839 int register_rpc_pipefs(void)
 840 {
 841         rpc_inode_cachep = kmem_cache_create("rpc_inode_cache",
 842                                 sizeof(struct rpc_inode),
 843                                 0, (SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT|
 844                                                 SLAB_MEM_SPREAD),
 845                                 init_once, NULL);
 846         if (!rpc_inode_cachep)
 847                 return -ENOMEM;
 848         register_filesystem(&rpc_pipe_fs_type);
 849         return 0;
 850 }
 851
 852 void unregister_rpc_pipefs(void)
 853 {
 854         if (kmem_cache_destroy(rpc_inode_cachep))
 855                 printk(KERN_WARNING "RPC: unable to free inode cache\n");
 856         unregister_filesystem(&rpc_pipe_fs_type);
 857 }