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   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/fsnotify.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 /**
  80  * rpc_queue_upcall
  81  * @inode: inode of upcall pipe on which to queue given message
  82  * @msg: message to queue
  83  *
  84  * Call with an @inode created by rpc_mkpipe() to queue an upcall.
  85  * A userspace process may then later read the upcall by performing a
  86  * read on an open file for this inode.  It is up to the caller to
  87  * initialize the fields of @msg (other than @msg->list) appropriately.
  88  */
  89 int
  90 rpc_queue_upcall(struct inode *inode, struct rpc_pipe_msg *msg)
  91 {
  92         struct rpc_inode *rpci = RPC_I(inode);
  93         int res = -EPIPE;
  94
  95         spin_lock(&inode->i_lock);
  96         if (rpci->ops == NULL)
  97                 goto out;
  98         if (rpci->nreaders) {
  99                 list_add_tail(&msg->list, &rpci->pipe);
 100                 rpci->pipelen += msg->len;
 101                 res = 0;
 102         } else if (rpci->flags & RPC_PIPE_WAIT_FOR_OPEN) {
 103                 if (list_empty(&rpci->pipe))
 104                         queue_delayed_work(rpciod_workqueue,
 105                                         &rpci->queue_timeout,
 106                                         RPC_UPCALL_TIMEOUT);
 107                 list_add_tail(&msg->list, &rpci->pipe);
 108                 rpci->pipelen += msg->len;
 109                 res = 0;
 110         }
 111 out:
 112         spin_unlock(&inode->i_lock);
 113         wake_up(&rpci->waitq);
 114         return res;
 115 }
 116 EXPORT_SYMBOL_GPL(rpc_queue_upcall);
 117
 118 static inline void
 119 rpc_inode_setowner(struct inode *inode, void *private)
 120 {
 121         RPC_I(inode)->private = private;
 122 }
 123
 124 static void
 125 rpc_close_pipes(struct inode *inode)
 126 {
 127         struct rpc_inode *rpci = RPC_I(inode);
 128         struct rpc_pipe_ops *ops;
 129
 130         mutex_lock(&inode->i_mutex);
 131         ops = rpci->ops;
 132         if (ops != NULL) {
 133                 LIST_HEAD(free_list);
 134
 135                 spin_lock(&inode->i_lock);
 136                 rpci->nreaders = 0;
 137                 list_splice_init(&rpci->in_upcall, &free_list);
 138                 list_splice_init(&rpci->pipe, &free_list);
 139                 rpci->pipelen = 0;
 140                 rpci->ops = NULL;
 141                 spin_unlock(&inode->i_lock);
 142                 rpc_purge_list(rpci, &free_list, ops->destroy_msg, -EPIPE);
 143                 rpci->nwriters = 0;
 144                 if (ops->release_pipe)
 145                         ops->release_pipe(inode);
 146                 cancel_delayed_work_sync(&rpci->queue_timeout);
 147         }
 148         rpc_inode_setowner(inode, NULL);
 149         mutex_unlock(&inode->i_mutex);
 150 }
 151
 152 static struct inode *
 153 rpc_alloc_inode(struct super_block *sb)
 154 {
 155         struct rpc_inode *rpci;
 156         rpci = (struct rpc_inode *)kmem_cache_alloc(rpc_inode_cachep, GFP_KERNEL);
 157         if (!rpci)
 158                 return NULL;
 159         return &rpci->vfs_inode;
 160 }
 161
 162 static void
 163 rpc_destroy_inode(struct inode *inode)
 164 {
 165         kmem_cache_free(rpc_inode_cachep, RPC_I(inode));
 166 }
 167
 168 static int
 169 rpc_pipe_open(struct inode *inode, struct file *filp)
 170 {
 171         struct rpc_inode *rpci = RPC_I(inode);
 172         int first_open;
 173         int res = -ENXIO;
 174
 175         mutex_lock(&inode->i_mutex);
 176         if (rpci->ops == NULL)
 177                 goto out;
 178         first_open = rpci->nreaders == 0 && rpci->nwriters == 0;
 179         if (first_open && rpci->ops->open_pipe) {
 180                 res = rpci->ops->open_pipe(inode);
 181                 if (res)
 182                         goto out;
 183         }
 184         if (filp->f_mode & FMODE_READ)
 185                 rpci->nreaders++;
 186         if (filp->f_mode & FMODE_WRITE)
 187                 rpci->nwriters++;
 188         res = 0;
 189 out:
 190         mutex_unlock(&inode->i_mutex);
 191         return res;
 192 }
 193
 194 static int
 195 rpc_pipe_release(struct inode *inode, struct file *filp)
 196 {
 197         struct rpc_inode *rpci = RPC_I(inode);
 198         struct rpc_pipe_msg *msg;
 199
 200         mutex_lock(&inode->i_mutex);
 201         if (rpci->ops == NULL)
 202                 goto out;
 203         msg = (struct rpc_pipe_msg *)filp->private_data;
 204         if (msg != NULL) {
 205                 spin_lock(&inode->i_lock);
 206                 msg->errno = -EAGAIN;
 207                 list_del(&msg->list);
 208                 spin_unlock(&inode->i_lock);
 209                 rpci->ops->destroy_msg(msg);
 210         }
 211         if (filp->f_mode & FMODE_WRITE)
 212                 rpci->nwriters --;
 213         if (filp->f_mode & FMODE_READ) {
 214                 rpci->nreaders --;
 215                 if (rpci->nreaders == 0) {
 216                         LIST_HEAD(free_list);
 217                         spin_lock(&inode->i_lock);
 218                         list_splice_init(&rpci->pipe, &free_list);
 219                         rpci->pipelen = 0;
 220                         spin_unlock(&inode->i_lock);
 221                         rpc_purge_list(rpci, &free_list,
 222                                         rpci->ops->destroy_msg, -EAGAIN);
 223                 }
 224         }
 225         if (rpci->ops->release_pipe)
 226                 rpci->ops->release_pipe(inode);
 227 out:
 228         mutex_unlock(&inode->i_mutex);
 229         return 0;
 230 }
 231
 232 static ssize_t
 233 rpc_pipe_read(struct file *filp, char __user *buf, size_t len, loff_t *offset)
 234 {
 235         struct inode *inode = filp->f_path.dentry->d_inode;
 236         struct rpc_inode *rpci = RPC_I(inode);
 237         struct rpc_pipe_msg *msg;
 238         int res = 0;
 239
 240         mutex_lock(&inode->i_mutex);
 241         if (rpci->ops == NULL) {
 242                 res = -EPIPE;
 243                 goto out_unlock;
 244         }
 245         msg = filp->private_data;
 246         if (msg == NULL) {
 247                 spin_lock(&inode->i_lock);
 248                 if (!list_empty(&rpci->pipe)) {
 249                         msg = list_entry(rpci->pipe.next,
 250                                         struct rpc_pipe_msg,
 251                                         list);
 252                         list_move(&msg->list, &rpci->in_upcall);
 253                         rpci->pipelen -= msg->len;
 254                         filp->private_data = msg;
 255                         msg->copied = 0;
 256                 }
 257                 spin_unlock(&inode->i_lock);
 258                 if (msg == NULL)
 259                         goto out_unlock;
 260         }
 261         /* NOTE: it is up to the callback to update msg->copied */
 262         res = rpci->ops->upcall(filp, msg, buf, len);
 263         if (res < 0 || msg->len == msg->copied) {
 264                 filp->private_data = NULL;
 265                 spin_lock(&inode->i_lock);
 266                 list_del(&msg->list);
 267                 spin_unlock(&inode->i_lock);
 268                 rpci->ops->destroy_msg(msg);
 269         }
 270 out_unlock:
 271         mutex_unlock(&inode->i_mutex);
 272         return res;
 273 }
 274
 275 static ssize_t
 276 rpc_pipe_write(struct file *filp, const char __user *buf, size_t len, loff_t *offset)
 277 {
 278         struct inode *inode = filp->f_path.dentry->d_inode;
 279         struct rpc_inode *rpci = RPC_I(inode);
 280         int res;
 281
 282         mutex_lock(&inode->i_mutex);
 283         res = -EPIPE;
 284         if (rpci->ops != NULL)
 285                 res = rpci->ops->downcall(filp, buf, len);
 286         mutex_unlock(&inode->i_mutex);
 287         return res;
 288 }
 289
 290 static unsigned int
 291 rpc_pipe_poll(struct file *filp, struct poll_table_struct *wait)
 292 {
 293         struct rpc_inode *rpci;
 294         unsigned int mask = 0;
 295
 296         rpci = RPC_I(filp->f_path.dentry->d_inode);
 297         poll_wait(filp, &rpci->waitq, wait);
 298
 299         mask = POLLOUT | POLLWRNORM;
 300         if (rpci->ops == NULL)
 301                 mask |= POLLERR | POLLHUP;
 302         if (filp->private_data || !list_empty(&rpci->pipe))
 303                 mask |= POLLIN | POLLRDNORM;
 304         return mask;
 305 }
 306
 307 static int
 308 rpc_pipe_ioctl(struct inode *ino, struct file *filp,
 309                 unsigned int cmd, unsigned long arg)
 310 {
 311         struct rpc_inode *rpci = RPC_I(filp->f_path.dentry->d_inode);
 312         int len;
 313
 314         switch (cmd) {
 315         case FIONREAD:
 316                 if (rpci->ops == NULL)
 317                         return -EPIPE;
 318                 len = rpci->pipelen;
 319                 if (filp->private_data) {
 320                         struct rpc_pipe_msg *msg;
 321                         msg = (struct rpc_pipe_msg *)filp->private_data;
 322                         len += msg->len - msg->copied;
 323                 }
 324                 return put_user(len, (int __user *)arg);
 325         default:
 326                 return -EINVAL;
 327         }
 328 }
 329
 330 static const struct file_operations rpc_pipe_fops = {
 331         .owner          = THIS_MODULE,
 332         .llseek         = no_llseek,
 333         .read           = rpc_pipe_read,
 334         .write          = rpc_pipe_write,
 335         .poll           = rpc_pipe_poll,
 336         .ioctl          = rpc_pipe_ioctl,
 337         .open           = rpc_pipe_open,
 338         .release        = rpc_pipe_release,
 339 };
 340
 341 static int
 342 rpc_show_info(struct seq_file *m, void *v)
 343 {
 344         struct rpc_clnt *clnt = m->private;
 345
 346         seq_printf(m, "RPC server: %s\n", clnt->cl_server);
 347         seq_printf(m, "service: %s (%d) version %d\n", clnt->cl_protname,
 348                         clnt->cl_prog, clnt->cl_vers);
 349         seq_printf(m, "address: %s\n", rpc_peeraddr2str(clnt, RPC_DISPLAY_ADDR));
 350         seq_printf(m, "protocol: %s\n", rpc_peeraddr2str(clnt, RPC_DISPLAY_PROTO));
 351         seq_printf(m, "port: %s\n", rpc_peeraddr2str(clnt, RPC_DISPLAY_PORT));
 352         return 0;
 353 }
 354
 355 static int
 356 rpc_info_open(struct inode *inode, struct file *file)
 357 {
 358         struct rpc_clnt *clnt;
 359         int ret = single_open(file, rpc_show_info, NULL);
 360
 361         if (!ret) {
 362                 struct seq_file *m = file->private_data;
 363                 mutex_lock(&inode->i_mutex);
 364                 clnt = RPC_I(inode)->private;
 365                 if (clnt) {
 366                         kref_get(&clnt->cl_kref);
 367                         m->private = clnt;
 368                 } else {
 369                         single_release(inode, file);
 370                         ret = -EINVAL;
 371                 }
 372                 mutex_unlock(&inode->i_mutex);
 373         }
 374         return ret;
 375 }
 376
 377 static int
 378 rpc_info_release(struct inode *inode, struct file *file)
 379 {
 380         struct seq_file *m = file->private_data;
 381         struct rpc_clnt *clnt = (struct rpc_clnt *)m->private;
 382
 383         if (clnt)
 384                 rpc_release_client(clnt);
 385         return single_release(inode, file);
 386 }
 387
 388 static const struct file_operations rpc_info_operations = {
 389         .owner          = THIS_MODULE,
 390         .open           = rpc_info_open,
 391         .read           = seq_read,
 392         .llseek         = seq_lseek,
 393         .release        = rpc_info_release,
 394 };
 395
 396
 397 /*
 398  * We have a single directory with 1 node in it.
 399  */
 400 enum {
 401         RPCAUTH_Root = 1,
 402         RPCAUTH_lockd,
 403         RPCAUTH_mount,
 404         RPCAUTH_nfs,
 405         RPCAUTH_portmap,
 406         RPCAUTH_statd,
 407         RPCAUTH_RootEOF
 408 };
 409
 410 /*
 411  * Description of fs contents.
 412  */
 413 struct rpc_filelist {
 414         char *name;
 415         const struct file_operations *i_fop;
 416         int mode;
 417 };
 418
 419 static struct rpc_filelist files[] = {
 420         [RPCAUTH_lockd] = {
 421                 .name = "lockd",
 422                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
 423         },
 424         [RPCAUTH_mount] = {
 425                 .name = "mount",
 426                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
 427         },
 428         [RPCAUTH_nfs] = {
 429                 .name = "nfs",
 430                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
 431         },
 432         [RPCAUTH_portmap] = {
 433                 .name = "portmap",
 434                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
 435         },
 436         [RPCAUTH_statd] = {
 437                 .name = "statd",
 438                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
 439         },
 440 };
 441
 442 enum {
 443         RPCAUTH_info = 2,
 444         RPCAUTH_EOF
 445 };
 446
 447 static struct rpc_filelist authfiles[] = {
 448         [RPCAUTH_info] = {
 449                 .name = "info",
 450                 .i_fop = &rpc_info_operations,
 451                 .mode = S_IFREG | S_IRUSR,
 452         },
 453 };
 454
 455 struct vfsmount *rpc_get_mount(void)
 456 {
 457         int err;
 458
 459         err = simple_pin_fs(&rpc_pipe_fs_type, &rpc_mount, &rpc_mount_count);
 460         if (err != 0)
 461                 return ERR_PTR(err);
 462         return rpc_mount;
 463 }
 464
 465 void rpc_put_mount(void)
 466 {
 467         simple_release_fs(&rpc_mount, &rpc_mount_count);
 468 }
 469
 470 static int rpc_delete_dentry(struct dentry *dentry)
 471 {
 472         return 1;
 473 }
 474
 475 static struct dentry_operations rpc_dentry_operations = {
 476         .d_delete = rpc_delete_dentry,
 477 };
 478
 479 static int
 480 rpc_lookup_parent(char *path, struct nameidata *nd)
 481 {
 482         struct vfsmount *mnt;
 483
 484         if (path[0] == '\0')
 485                 return -ENOENT;
 486
 487         mnt = rpc_get_mount();
 488         if (IS_ERR(mnt)) {
 489                 printk(KERN_WARNING "%s: %s failed to mount "
 490                                "pseudofilesystem \n", __FILE__, __func__);
 491                 return PTR_ERR(mnt);
 492         }
 493
 494         if (vfs_path_lookup(mnt->mnt_root, mnt, path, LOOKUP_PARENT, nd)) {
 495                 printk(KERN_WARNING "%s: %s failed to find path %s\n",
 496                                 __FILE__, __func__, path);
 497                 rpc_put_mount();
 498                 return -ENOENT;
 499         }
 500         return 0;
 501 }
 502
 503 static void
 504 rpc_release_path(struct nameidata *nd)
 505 {
 506         path_put(&nd->path);
 507         rpc_put_mount();
 508 }
 509
 510 static struct inode *
 511 rpc_get_inode(struct super_block *sb, int mode)
 512 {
 513         struct inode *inode = new_inode(sb);
 514         if (!inode)
 515                 return NULL;
 516         inode->i_mode = mode;
 517         inode->i_uid = inode->i_gid = 0;
 518         inode->i_blocks = 0;
 519         inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
 520         switch(mode & S_IFMT) {
 521                 case S_IFDIR:
 522                         inode->i_fop = &simple_dir_operations;
 523                         inode->i_op = &simple_dir_inode_operations;
 524                         inc_nlink(inode);
 525                 default:
 526                         break;
 527         }
 528         return inode;
 529 }
 530
 531 /*
 532  * FIXME: This probably has races.
 533  */
 534 static void rpc_depopulate(struct dentry *parent,
 535                            unsigned long start, unsigned long eof)
 536 {
 537         struct inode *dir = parent->d_inode;
 538         struct list_head *pos, *next;
 539         struct dentry *dentry, *dvec[10];
 540         int n = 0;
 541
 542         mutex_lock_nested(&dir->i_mutex, I_MUTEX_CHILD);
 543 repeat:
 544         spin_lock(&dcache_lock);
 545         list_for_each_safe(pos, next, &parent->d_subdirs) {
 546                 dentry = list_entry(pos, struct dentry, d_u.d_child);
 547                 if (!dentry->d_inode ||
 548                                 dentry->d_inode->i_ino < start ||
 549                                 dentry->d_inode->i_ino >= eof)
 550                         continue;
 551                 spin_lock(&dentry->d_lock);
 552                 if (!d_unhashed(dentry)) {
 553                         dget_locked(dentry);
 554                         __d_drop(dentry);
 555                         spin_unlock(&dentry->d_lock);
 556                         dvec[n++] = dentry;
 557                         if (n == ARRAY_SIZE(dvec))
 558                                 break;
 559                 } else
 560                         spin_unlock(&dentry->d_lock);
 561         }
 562         spin_unlock(&dcache_lock);
 563         if (n) {
 564                 do {
 565                         dentry = dvec[--n];
 566                         if (S_ISREG(dentry->d_inode->i_mode))
 567                                 simple_unlink(dir, dentry);
 568                         else if (S_ISDIR(dentry->d_inode->i_mode))
 569                                 simple_rmdir(dir, dentry);
 570                         d_delete(dentry);
 571                         dput(dentry);
 572                 } while (n);
 573                 goto repeat;
 574         }
 575         mutex_unlock(&dir->i_mutex);
 576 }
 577
 578 static int
 579 rpc_populate(struct dentry *parent,
 580                 struct rpc_filelist *files,
 581                 int start, int eof)
 582 {
 583         struct inode *inode, *dir = parent->d_inode;
 584         void *private = RPC_I(dir)->private;
 585         struct dentry *dentry;
 586         int mode, i;
 587
 588         mutex_lock(&dir->i_mutex);
 589         for (i = start; i < eof; i++) {
 590                 dentry = d_alloc_name(parent, files[i].name);
 591                 if (!dentry)
 592                         goto out_bad;
 593                 dentry->d_op = &rpc_dentry_operations;
 594                 mode = files[i].mode;
 595                 inode = rpc_get_inode(dir->i_sb, mode);
 596                 if (!inode) {
 597                         dput(dentry);
 598                         goto out_bad;
 599                 }
 600                 inode->i_ino = i;
 601                 if (files[i].i_fop)
 602                         inode->i_fop = files[i].i_fop;
 603                 if (private)
 604                         rpc_inode_setowner(inode, private);
 605                 if (S_ISDIR(mode))
 606                         inc_nlink(dir);
 607                 d_add(dentry, inode);
 608                 fsnotify_create(dir, dentry);
 609         }
 610         mutex_unlock(&dir->i_mutex);
 611         return 0;
 612 out_bad:
 613         mutex_unlock(&dir->i_mutex);
 614         printk(KERN_WARNING "%s: %s failed to populate directory %s\n",
 615                         __FILE__, __func__, parent->d_name.name);
 616         return -ENOMEM;
 617 }
 618
 619 static int
 620 __rpc_mkdir(struct inode *dir, struct dentry *dentry)
 621 {
 622         struct inode *inode;
 623
 624         inode = rpc_get_inode(dir->i_sb, S_IFDIR | S_IRUGO | S_IXUGO);
 625         if (!inode)
 626                 goto out_err;
 627         inode->i_ino = iunique(dir->i_sb, 100);
 628         d_instantiate(dentry, inode);
 629         inc_nlink(dir);
 630         fsnotify_mkdir(dir, dentry);
 631         return 0;
 632 out_err:
 633         printk(KERN_WARNING "%s: %s failed to allocate inode for dentry %s\n",
 634                         __FILE__, __func__, dentry->d_name.name);
 635         return -ENOMEM;
 636 }
 637
 638 static int
 639 __rpc_rmdir(struct inode *dir, struct dentry *dentry)
 640 {
 641         int error;
 642         error = simple_rmdir(dir, dentry);
 643         if (!error)
 644                 d_delete(dentry);
 645         return error;
 646 }
 647
 648 static struct dentry *
 649 rpc_lookup_create(struct dentry *parent, const char *name, int len, int exclusive)
 650 {
 651         struct inode *dir = parent->d_inode;
 652         struct dentry *dentry;
 653
 654         mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
 655         dentry = lookup_one_len(name, parent, len);
 656         if (IS_ERR(dentry))
 657                 goto out_err;
 658         if (!dentry->d_inode)
 659                 dentry->d_op = &rpc_dentry_operations;
 660         else if (exclusive) {
 661                 dput(dentry);
 662                 dentry = ERR_PTR(-EEXIST);
 663                 goto out_err;
 664         }
 665         return dentry;
 666 out_err:
 667         mutex_unlock(&dir->i_mutex);
 668         return dentry;
 669 }
 670
 671 static struct dentry *
 672 rpc_lookup_negative(char *path, struct nameidata *nd)
 673 {
 674         struct dentry *dentry;
 675         int error;
 676
 677         if ((error = rpc_lookup_parent(path, nd)) != 0)
 678                 return ERR_PTR(error);
 679         dentry = rpc_lookup_create(nd->path.dentry, nd->last.name, nd->last.len,
 680                                    1);
 681         if (IS_ERR(dentry))
 682                 rpc_release_path(nd);
 683         return dentry;
 684 }
 685
 686 /**
 687  * rpc_mkdir - Create a new directory in rpc_pipefs
 688  * @path: path from the rpc_pipefs root to the new directory
 689  * @rpc_client: rpc client to associate with this directory
 690  *
 691  * This creates a directory at the given @path associated with
 692  * @rpc_clnt, which will contain a file named "info" with some basic
 693  * information about the client, together with any "pipes" that may
 694  * later be created using rpc_mkpipe().
 695  */
 696 struct dentry *
 697 rpc_mkdir(char *path, struct rpc_clnt *rpc_client)
 698 {
 699         struct nameidata nd;
 700         struct dentry *dentry;
 701         struct inode *dir;
 702         int error;
 703
 704         dentry = rpc_lookup_negative(path, &nd);
 705         if (IS_ERR(dentry))
 706                 return dentry;
 707         dir = nd.path.dentry->d_inode;
 708         if ((error = __rpc_mkdir(dir, dentry)) != 0)
 709                 goto err_dput;
 710         RPC_I(dentry->d_inode)->private = rpc_client;
 711         error = rpc_populate(dentry, authfiles,
 712                         RPCAUTH_info, RPCAUTH_EOF);
 713         if (error)
 714                 goto err_depopulate;
 715         dget(dentry);
 716 out:
 717         mutex_unlock(&dir->i_mutex);
 718         rpc_release_path(&nd);
 719         return dentry;
 720 err_depopulate:
 721         rpc_depopulate(dentry, RPCAUTH_info, RPCAUTH_EOF);
 722         __rpc_rmdir(dir, dentry);
 723 err_dput:
 724         dput(dentry);
 725         printk(KERN_WARNING "%s: %s() failed to create directory %s (errno = %d)\n",
 726                         __FILE__, __func__, path, error);
 727         dentry = ERR_PTR(error);
 728         goto out;
 729 }
 730
 731 /**
 732  * rpc_rmdir - Remove a directory created with rpc_mkdir()
 733  * @dentry: directory to remove
 734  */
 735 int
 736 rpc_rmdir(struct dentry *dentry)
 737 {
 738         struct dentry *parent;
 739         struct inode *dir;
 740         int error;
 741
 742         parent = dget_parent(dentry);
 743         dir = parent->d_inode;
 744         mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
 745         rpc_depopulate(dentry, RPCAUTH_info, RPCAUTH_EOF);
 746         error = __rpc_rmdir(dir, dentry);
 747         dput(dentry);
 748         mutex_unlock(&dir->i_mutex);
 749         dput(parent);
 750         return error;
 751 }
 752
 753 /**
 754  * rpc_mkpipe - make an rpc_pipefs file for kernel<->userspace communication
 755  * @parent: dentry of directory to create new "pipe" in
 756  * @name: name of pipe
 757  * @private: private data to associate with the pipe, for the caller's use
 758  * @ops: operations defining the behavior of the pipe: upcall, downcall,
 759  *      release_pipe, open_pipe, and destroy_msg.
 760  * @flags: rpc_inode flags
 761  *
 762  * Data is made available for userspace to read by calls to
 763  * rpc_queue_upcall().  The actual reads will result in calls to
 764  * @ops->upcall, which will be called with the file pointer,
 765  * message, and userspace buffer to copy to.
 766  *
 767  * Writes can come at any time, and do not necessarily have to be
 768  * responses to upcalls.  They will result in calls to @msg->downcall.
 769  *
 770  * The @private argument passed here will be available to all these methods
 771  * from the file pointer, via RPC_I(file->f_dentry->d_inode)->private.
 772  */
 773 struct dentry *
 774 rpc_mkpipe(struct dentry *parent, const char *name, void *private, struct rpc_pipe_ops *ops, int flags)
 775 {
 776         struct dentry *dentry;
 777         struct inode *dir, *inode;
 778         struct rpc_inode *rpci;
 779
 780         dentry = rpc_lookup_create(parent, name, strlen(name), 0);
 781         if (IS_ERR(dentry))
 782                 return dentry;
 783         dir = parent->d_inode;
 784         if (dentry->d_inode) {
 785                 rpci = RPC_I(dentry->d_inode);
 786                 if (rpci->private != private ||
 787                                 rpci->ops != ops ||
 788                                 rpci->flags != flags) {
 789                         dput (dentry);
 790                         dentry = ERR_PTR(-EBUSY);
 791                 }
 792                 rpci->nkern_readwriters++;
 793                 goto out;
 794         }
 795         inode = rpc_get_inode(dir->i_sb, S_IFIFO | S_IRUSR | S_IWUSR);
 796         if (!inode)
 797                 goto err_dput;
 798         inode->i_ino = iunique(dir->i_sb, 100);
 799         inode->i_fop = &rpc_pipe_fops;
 800         d_instantiate(dentry, inode);
 801         rpci = RPC_I(inode);
 802         rpci->private = private;
 803         rpci->flags = flags;
 804         rpci->ops = ops;
 805         rpci->nkern_readwriters = 1;
 806         fsnotify_create(dir, dentry);
 807         dget(dentry);
 808 out:
 809         mutex_unlock(&dir->i_mutex);
 810         return dentry;
 811 err_dput:
 812         dput(dentry);
 813         dentry = ERR_PTR(-ENOMEM);
 814         printk(KERN_WARNING "%s: %s() failed to create pipe %s/%s (errno = %d)\n",
 815                         __FILE__, __func__, parent->d_name.name, name,
 816                         -ENOMEM);
 817         goto out;
 818 }
 819 EXPORT_SYMBOL_GPL(rpc_mkpipe);
 820
 821 /**
 822  * rpc_unlink - remove a pipe
 823  * @dentry: dentry for the pipe, as returned from rpc_mkpipe
 824  *
 825  * After this call, lookups will no longer find the pipe, and any
 826  * attempts to read or write using preexisting opens of the pipe will
 827  * return -EPIPE.
 828  */
 829 int
 830 rpc_unlink(struct dentry *dentry)
 831 {
 832         struct dentry *parent;
 833         struct inode *dir;
 834         int error = 0;
 835
 836         parent = dget_parent(dentry);
 837         dir = parent->d_inode;
 838         mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
 839         if (--RPC_I(dentry->d_inode)->nkern_readwriters == 0) {
 840                 rpc_close_pipes(dentry->d_inode);
 841                 error = simple_unlink(dir, dentry);
 842                 if (!error)
 843                         d_delete(dentry);
 844         }
 845         dput(dentry);
 846         mutex_unlock(&dir->i_mutex);
 847         dput(parent);
 848         return error;
 849 }
 850 EXPORT_SYMBOL_GPL(rpc_unlink);
 851
 852 /*
 853  * populate the filesystem
 854  */
 855 static struct super_operations s_ops = {
 856         .alloc_inode    = rpc_alloc_inode,
 857         .destroy_inode  = rpc_destroy_inode,
 858         .statfs         = simple_statfs,
 859 };
 860
 861 #define RPCAUTH_GSSMAGIC 0x67596969
 862
 863 static int
 864 rpc_fill_super(struct super_block *sb, void *data, int silent)
 865 {
 866         struct inode *inode;
 867         struct dentry *root;
 868
 869         sb->s_blocksize = PAGE_CACHE_SIZE;
 870         sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
 871         sb->s_magic = RPCAUTH_GSSMAGIC;
 872         sb->s_op = &s_ops;
 873         sb->s_time_gran = 1;
 874
 875         inode = rpc_get_inode(sb, S_IFDIR | 0755);
 876         if (!inode)
 877                 return -ENOMEM;
 878         root = d_alloc_root(inode);
 879         if (!root) {
 880                 iput(inode);
 881                 return -ENOMEM;
 882         }
 883         if (rpc_populate(root, files, RPCAUTH_Root + 1, RPCAUTH_RootEOF))
 884                 goto out;
 885         sb->s_root = root;
 886         return 0;
 887 out:
 888         d_genocide(root);
 889         dput(root);
 890         return -ENOMEM;
 891 }
 892
 893 static int
 894 rpc_get_sb(struct file_system_type *fs_type,
 895                 int flags, const char *dev_name, void *data, struct vfsmount *mnt)
 896 {
 897         return get_sb_single(fs_type, flags, data, rpc_fill_super, mnt);
 898 }
 899
 900 static struct file_system_type rpc_pipe_fs_type = {
 901         .owner          = THIS_MODULE,
 902         .name           = "rpc_pipefs",
 903         .get_sb         = rpc_get_sb,
 904         .kill_sb        = kill_litter_super,
 905 };
 906
 907 static void
 908 init_once(void *foo)
 909 {
 910         struct rpc_inode *rpci = (struct rpc_inode *) foo;
 911
 912         inode_init_once(&rpci->vfs_inode);
 913         rpci->private = NULL;
 914         rpci->nreaders = 0;
 915         rpci->nwriters = 0;
 916         INIT_LIST_HEAD(&rpci->in_upcall);
 917         INIT_LIST_HEAD(&rpci->in_downcall);
 918         INIT_LIST_HEAD(&rpci->pipe);
 919         rpci->pipelen = 0;
 920         init_waitqueue_head(&rpci->waitq);
 921         INIT_DELAYED_WORK(&rpci->queue_timeout,
 922                             rpc_timeout_upcall_queue);
 923         rpci->ops = NULL;
 924 }
 925
 926 int register_rpc_pipefs(void)
 927 {
 928         int err;
 929
 930         rpc_inode_cachep = kmem_cache_create("rpc_inode_cache",
 931                                 sizeof(struct rpc_inode),
 932                                 0, (SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT|
 933                                                 SLAB_MEM_SPREAD),
 934                                 init_once);
 935         if (!rpc_inode_cachep)
 936                 return -ENOMEM;
 937         err = register_filesystem(&rpc_pipe_fs_type);
 938         if (err) {
 939                 kmem_cache_destroy(rpc_inode_cachep);
 940                 return err;
 941         }
 942
 943         return 0;
 944 }
 945
 946 void unregister_rpc_pipefs(void)
 947 {
 948         kmem_cache_destroy(rpc_inode_cachep);
 949         unregister_filesystem(&rpc_pipe_fs_type);
 950 }