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/fsnotify.h>
  18 #include <linux/kernel.h>
  19 #include <linux/rcupdate.h>
  20
  21 #include <asm/ioctls.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 #include <linux/sunrpc/cache.h>
  30 #include <linux/nsproxy.h>
  31 #include <linux/notifier.h>
  32
  33 #include "netns.h"
  34 #include "sunrpc.h"
  35
  36 #define RPCDBG_FACILITY RPCDBG_DEBUG
  37
  38 #define NET_NAME(net)   ((net == &init_net) ? " (init_net)" : "")
  39
  40 static struct file_system_type rpc_pipe_fs_type;
  41 static const struct rpc_pipe_ops gssd_dummy_pipe_ops;
  42
  43 static struct kmem_cache *rpc_inode_cachep __read_mostly;
  44
  45 #define RPC_UPCALL_TIMEOUT (30*HZ)
  46
  47 static BLOCKING_NOTIFIER_HEAD(rpc_pipefs_notifier_list);
  48
  49 int rpc_pipefs_notifier_register(struct notifier_block *nb)
  50 {
  51         return blocking_notifier_chain_cond_register(&rpc_pipefs_notifier_list, nb);
  52 }
  53 EXPORT_SYMBOL_GPL(rpc_pipefs_notifier_register);
  54
  55 void rpc_pipefs_notifier_unregister(struct notifier_block *nb)
  56 {
  57         blocking_notifier_chain_unregister(&rpc_pipefs_notifier_list, nb);
  58 }
  59 EXPORT_SYMBOL_GPL(rpc_pipefs_notifier_unregister);
  60
  61 static void rpc_purge_list(wait_queue_head_t *waitq, struct list_head *head,
  62                 void (*destroy_msg)(struct rpc_pipe_msg *), int err)
  63 {
  64         struct rpc_pipe_msg *msg;
  65
  66         if (list_empty(head))
  67                 return;
  68         do {
  69                 msg = list_entry(head->next, struct rpc_pipe_msg, list);
  70                 list_del_init(&msg->list);
  71                 msg->errno = err;
  72                 destroy_msg(msg);
  73         } while (!list_empty(head));
  74
  75         if (waitq)
  76                 wake_up(waitq);
  77 }
  78
  79 static void
  80 rpc_timeout_upcall_queue(struct work_struct *work)
  81 {
  82         LIST_HEAD(free_list);
  83         struct rpc_pipe *pipe =
  84                 container_of(work, struct rpc_pipe, queue_timeout.work);
  85         void (*destroy_msg)(struct rpc_pipe_msg *);
  86         struct dentry *dentry;
  87
  88         spin_lock(&pipe->lock);
  89         destroy_msg = pipe->ops->destroy_msg;
  90         if (pipe->nreaders == 0) {
  91                 list_splice_init(&pipe->pipe, &free_list);
  92                 pipe->pipelen = 0;
  93         }
  94         dentry = dget(pipe->dentry);
  95         spin_unlock(&pipe->lock);
  96         rpc_purge_list(dentry ? &RPC_I(dentry->d_inode)->waitq : NULL,
  97                         &free_list, destroy_msg, -ETIMEDOUT);
  98         dput(dentry);
  99 }
 100
 101 ssize_t rpc_pipe_generic_upcall(struct file *filp, struct rpc_pipe_msg *msg,
 102                                 char __user *dst, size_t buflen)
 103 {
 104         char *data = (char *)msg->data + msg->copied;
 105         size_t mlen = min(msg->len - msg->copied, buflen);
 106         unsigned long left;
 107
 108         left = copy_to_user(dst, data, mlen);
 109         if (left == mlen) {
 110                 msg->errno = -EFAULT;
 111                 return -EFAULT;
 112         }
 113
 114         mlen -= left;
 115         msg->copied += mlen;
 116         msg->errno = 0;
 117         return mlen;
 118 }
 119 EXPORT_SYMBOL_GPL(rpc_pipe_generic_upcall);
 120
 121 /**
 122  * rpc_queue_upcall - queue an upcall message to userspace
 123  * @pipe: upcall pipe on which to queue given message
 124  * @msg: message to queue
 125  *
 126  * Call with an @inode created by rpc_mkpipe() to queue an upcall.
 127  * A userspace process may then later read the upcall by performing a
 128  * read on an open file for this inode.  It is up to the caller to
 129  * initialize the fields of @msg (other than @msg->list) appropriately.
 130  */
 131 int
 132 rpc_queue_upcall(struct rpc_pipe *pipe, struct rpc_pipe_msg *msg)
 133 {
 134         int res = -EPIPE;
 135         struct dentry *dentry;
 136
 137         spin_lock(&pipe->lock);
 138         if (pipe->nreaders) {
 139                 list_add_tail(&msg->list, &pipe->pipe);
 140                 pipe->pipelen += msg->len;
 141                 res = 0;
 142         } else if (pipe->flags & RPC_PIPE_WAIT_FOR_OPEN) {
 143                 if (list_empty(&pipe->pipe))
 144                         queue_delayed_work(rpciod_workqueue,
 145                                         &pipe->queue_timeout,
 146                                         RPC_UPCALL_TIMEOUT);
 147                 list_add_tail(&msg->list, &pipe->pipe);
 148                 pipe->pipelen += msg->len;
 149                 res = 0;
 150         }
 151         dentry = dget(pipe->dentry);
 152         spin_unlock(&pipe->lock);
 153         if (dentry) {
 154                 wake_up(&RPC_I(dentry->d_inode)->waitq);
 155                 dput(dentry);
 156         }
 157         return res;
 158 }
 159 EXPORT_SYMBOL_GPL(rpc_queue_upcall);
 160
 161 static inline void
 162 rpc_inode_setowner(struct inode *inode, void *private)
 163 {
 164         RPC_I(inode)->private = private;
 165 }
 166
 167 static void
 168 rpc_close_pipes(struct inode *inode)
 169 {
 170         struct rpc_pipe *pipe = RPC_I(inode)->pipe;
 171         int need_release;
 172         LIST_HEAD(free_list);
 173
 174         mutex_lock(&inode->i_mutex);
 175         spin_lock(&pipe->lock);
 176         need_release = pipe->nreaders != 0 || pipe->nwriters != 0;
 177         pipe->nreaders = 0;
 178         list_splice_init(&pipe->in_upcall, &free_list);
 179         list_splice_init(&pipe->pipe, &free_list);
 180         pipe->pipelen = 0;
 181         pipe->dentry = NULL;
 182         spin_unlock(&pipe->lock);
 183         rpc_purge_list(&RPC_I(inode)->waitq, &free_list, pipe->ops->destroy_msg, -EPIPE);
 184         pipe->nwriters = 0;
 185         if (need_release && pipe->ops->release_pipe)
 186                 pipe->ops->release_pipe(inode);
 187         cancel_delayed_work_sync(&pipe->queue_timeout);
 188         rpc_inode_setowner(inode, NULL);
 189         RPC_I(inode)->pipe = NULL;
 190         mutex_unlock(&inode->i_mutex);
 191 }
 192
 193 static struct inode *
 194 rpc_alloc_inode(struct super_block *sb)
 195 {
 196         struct rpc_inode *rpci;
 197         rpci = (struct rpc_inode *)kmem_cache_alloc(rpc_inode_cachep, GFP_KERNEL);
 198         if (!rpci)
 199                 return NULL;
 200         return &rpci->vfs_inode;
 201 }
 202
 203 static void
 204 rpc_i_callback(struct rcu_head *head)
 205 {
 206         struct inode *inode = container_of(head, struct inode, i_rcu);
 207         kmem_cache_free(rpc_inode_cachep, RPC_I(inode));
 208 }
 209
 210 static void
 211 rpc_destroy_inode(struct inode *inode)
 212 {
 213         call_rcu(&inode->i_rcu, rpc_i_callback);
 214 }
 215
 216 static int
 217 rpc_pipe_open(struct inode *inode, struct file *filp)
 218 {
 219         struct rpc_pipe *pipe;
 220         int first_open;
 221         int res = -ENXIO;
 222
 223         mutex_lock(&inode->i_mutex);
 224         pipe = RPC_I(inode)->pipe;
 225         if (pipe == NULL)
 226                 goto out;
 227         first_open = pipe->nreaders == 0 && pipe->nwriters == 0;
 228         if (first_open && pipe->ops->open_pipe) {
 229                 res = pipe->ops->open_pipe(inode);
 230                 if (res)
 231                         goto out;
 232         }
 233         if (filp->f_mode & FMODE_READ)
 234                 pipe->nreaders++;
 235         if (filp->f_mode & FMODE_WRITE)
 236                 pipe->nwriters++;
 237         res = 0;
 238 out:
 239         mutex_unlock(&inode->i_mutex);
 240         return res;
 241 }
 242
 243 static int
 244 rpc_pipe_release(struct inode *inode, struct file *filp)
 245 {
 246         struct rpc_pipe *pipe;
 247         struct rpc_pipe_msg *msg;
 248         int last_close;
 249
 250         mutex_lock(&inode->i_mutex);
 251         pipe = RPC_I(inode)->pipe;
 252         if (pipe == NULL)
 253                 goto out;
 254         msg = filp->private_data;
 255         if (msg != NULL) {
 256                 spin_lock(&pipe->lock);
 257                 msg->errno = -EAGAIN;
 258                 list_del_init(&msg->list);
 259                 spin_unlock(&pipe->lock);
 260                 pipe->ops->destroy_msg(msg);
 261         }
 262         if (filp->f_mode & FMODE_WRITE)
 263                 pipe->nwriters --;
 264         if (filp->f_mode & FMODE_READ) {
 265                 pipe->nreaders --;
 266                 if (pipe->nreaders == 0) {
 267                         LIST_HEAD(free_list);
 268                         spin_lock(&pipe->lock);
 269                         list_splice_init(&pipe->pipe, &free_list);
 270                         pipe->pipelen = 0;
 271                         spin_unlock(&pipe->lock);
 272                         rpc_purge_list(&RPC_I(inode)->waitq, &free_list,
 273                                         pipe->ops->destroy_msg, -EAGAIN);
 274                 }
 275         }
 276         last_close = pipe->nwriters == 0 && pipe->nreaders == 0;
 277         if (last_close && pipe->ops->release_pipe)
 278                 pipe->ops->release_pipe(inode);
 279 out:
 280         mutex_unlock(&inode->i_mutex);
 281         return 0;
 282 }
 283
 284 static ssize_t
 285 rpc_pipe_read(struct file *filp, char __user *buf, size_t len, loff_t *offset)
 286 {
 287         struct inode *inode = file_inode(filp);
 288         struct rpc_pipe *pipe;
 289         struct rpc_pipe_msg *msg;
 290         int res = 0;
 291
 292         mutex_lock(&inode->i_mutex);
 293         pipe = RPC_I(inode)->pipe;
 294         if (pipe == NULL) {
 295                 res = -EPIPE;
 296                 goto out_unlock;
 297         }
 298         msg = filp->private_data;
 299         if (msg == NULL) {
 300                 spin_lock(&pipe->lock);
 301                 if (!list_empty(&pipe->pipe)) {
 302                         msg = list_entry(pipe->pipe.next,
 303                                         struct rpc_pipe_msg,
 304                                         list);
 305                         list_move(&msg->list, &pipe->in_upcall);
 306                         pipe->pipelen -= msg->len;
 307                         filp->private_data = msg;
 308                         msg->copied = 0;
 309                 }
 310                 spin_unlock(&pipe->lock);
 311                 if (msg == NULL)
 312                         goto out_unlock;
 313         }
 314         /* NOTE: it is up to the callback to update msg->copied */
 315         res = pipe->ops->upcall(filp, msg, buf, len);
 316         if (res < 0 || msg->len == msg->copied) {
 317                 filp->private_data = NULL;
 318                 spin_lock(&pipe->lock);
 319                 list_del_init(&msg->list);
 320                 spin_unlock(&pipe->lock);
 321                 pipe->ops->destroy_msg(msg);
 322         }
 323 out_unlock:
 324         mutex_unlock(&inode->i_mutex);
 325         return res;
 326 }
 327
 328 static ssize_t
 329 rpc_pipe_write(struct file *filp, const char __user *buf, size_t len, loff_t *offset)
 330 {
 331         struct inode *inode = file_inode(filp);
 332         int res;
 333
 334         mutex_lock(&inode->i_mutex);
 335         res = -EPIPE;
 336         if (RPC_I(inode)->pipe != NULL)
 337                 res = RPC_I(inode)->pipe->ops->downcall(filp, buf, len);
 338         mutex_unlock(&inode->i_mutex);
 339         return res;
 340 }
 341
 342 static unsigned int
 343 rpc_pipe_poll(struct file *filp, struct poll_table_struct *wait)
 344 {
 345         struct inode *inode = file_inode(filp);
 346         struct rpc_inode *rpci = RPC_I(inode);
 347         unsigned int mask = POLLOUT | POLLWRNORM;
 348
 349         poll_wait(filp, &rpci->waitq, wait);
 350
 351         mutex_lock(&inode->i_mutex);
 352         if (rpci->pipe == NULL)
 353                 mask |= POLLERR | POLLHUP;
 354         else if (filp->private_data || !list_empty(&rpci->pipe->pipe))
 355                 mask |= POLLIN | POLLRDNORM;
 356         mutex_unlock(&inode->i_mutex);
 357         return mask;
 358 }
 359
 360 static long
 361 rpc_pipe_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 362 {
 363         struct inode *inode = file_inode(filp);
 364         struct rpc_pipe *pipe;
 365         int len;
 366
 367         switch (cmd) {
 368         case FIONREAD:
 369                 mutex_lock(&inode->i_mutex);
 370                 pipe = RPC_I(inode)->pipe;
 371                 if (pipe == NULL) {
 372                         mutex_unlock(&inode->i_mutex);
 373                         return -EPIPE;
 374                 }
 375                 spin_lock(&pipe->lock);
 376                 len = pipe->pipelen;
 377                 if (filp->private_data) {
 378                         struct rpc_pipe_msg *msg;
 379                         msg = filp->private_data;
 380                         len += msg->len - msg->copied;
 381                 }
 382                 spin_unlock(&pipe->lock);
 383                 mutex_unlock(&inode->i_mutex);
 384                 return put_user(len, (int __user *)arg);
 385         default:
 386                 return -EINVAL;
 387         }
 388 }
 389
 390 static const struct file_operations rpc_pipe_fops = {
 391         .owner          = THIS_MODULE,
 392         .llseek         = no_llseek,
 393         .read           = rpc_pipe_read,
 394         .write          = rpc_pipe_write,
 395         .poll           = rpc_pipe_poll,
 396         .unlocked_ioctl = rpc_pipe_ioctl,
 397         .open           = rpc_pipe_open,
 398         .release        = rpc_pipe_release,
 399 };
 400
 401 static int
 402 rpc_show_info(struct seq_file *m, void *v)
 403 {
 404         struct rpc_clnt *clnt = m->private;
 405
 406         rcu_read_lock();
 407         seq_printf(m, "RPC server: %s\n",
 408                         rcu_dereference(clnt->cl_xprt)->servername);
 409         seq_printf(m, "service: %s (%d) version %d\n", clnt->cl_program->name,
 410                         clnt->cl_prog, clnt->cl_vers);
 411         seq_printf(m, "address: %s\n", rpc_peeraddr2str(clnt, RPC_DISPLAY_ADDR));
 412         seq_printf(m, "protocol: %s\n", rpc_peeraddr2str(clnt, RPC_DISPLAY_PROTO));
 413         seq_printf(m, "port: %s\n", rpc_peeraddr2str(clnt, RPC_DISPLAY_PORT));
 414         rcu_read_unlock();
 415         return 0;
 416 }
 417
 418 static int
 419 rpc_info_open(struct inode *inode, struct file *file)
 420 {
 421         struct rpc_clnt *clnt = NULL;
 422         int ret = single_open(file, rpc_show_info, NULL);
 423
 424         if (!ret) {
 425                 struct seq_file *m = file->private_data;
 426
 427                 spin_lock(&file->f_path.dentry->d_lock);
 428                 if (!d_unhashed(file->f_path.dentry))
 429                         clnt = RPC_I(inode)->private;
 430                 if (clnt != NULL && atomic_inc_not_zero(&clnt->cl_count)) {
 431                         spin_unlock(&file->f_path.dentry->d_lock);
 432                         m->private = clnt;
 433                 } else {
 434                         spin_unlock(&file->f_path.dentry->d_lock);
 435                         single_release(inode, file);
 436                         ret = -EINVAL;
 437                 }
 438         }
 439         return ret;
 440 }
 441
 442 static int
 443 rpc_info_release(struct inode *inode, struct file *file)
 444 {
 445         struct seq_file *m = file->private_data;
 446         struct rpc_clnt *clnt = (struct rpc_clnt *)m->private;
 447
 448         if (clnt)
 449                 rpc_release_client(clnt);
 450         return single_release(inode, file);
 451 }
 452
 453 static const struct file_operations rpc_info_operations = {
 454         .owner          = THIS_MODULE,
 455         .open           = rpc_info_open,
 456         .read           = seq_read,
 457         .llseek         = seq_lseek,
 458         .release        = rpc_info_release,
 459 };
 460
 461
 462 /*
 463  * Description of fs contents.
 464  */
 465 struct rpc_filelist {
 466         const char *name;
 467         const struct file_operations *i_fop;
 468         umode_t mode;
 469 };
 470
 471 static struct inode *
 472 rpc_get_inode(struct super_block *sb, umode_t mode)
 473 {
 474         struct inode *inode = new_inode(sb);
 475         if (!inode)
 476                 return NULL;
 477         inode->i_ino = get_next_ino();
 478         inode->i_mode = mode;
 479         inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
 480         switch (mode & S_IFMT) {
 481         case S_IFDIR:
 482                 inode->i_fop = &simple_dir_operations;
 483                 inode->i_op = &simple_dir_inode_operations;
 484                 inc_nlink(inode);
 485         default:
 486                 break;
 487         }
 488         return inode;
 489 }
 490
 491 static int __rpc_create_common(struct inode *dir, struct dentry *dentry,
 492                                umode_t mode,
 493                                const struct file_operations *i_fop,
 494                                void *private)
 495 {
 496         struct inode *inode;
 497
 498         d_drop(dentry);
 499         inode = rpc_get_inode(dir->i_sb, mode);
 500         if (!inode)
 501                 goto out_err;
 502         inode->i_ino = iunique(dir->i_sb, 100);
 503         if (i_fop)
 504                 inode->i_fop = i_fop;
 505         if (private)
 506                 rpc_inode_setowner(inode, private);
 507         d_add(dentry, inode);
 508         return 0;
 509 out_err:
 510         printk(KERN_WARNING "%s: %s failed to allocate inode for dentry %pd\n",
 511                         __FILE__, __func__, dentry);
 512         dput(dentry);
 513         return -ENOMEM;
 514 }
 515
 516 static int __rpc_create(struct inode *dir, struct dentry *dentry,
 517                         umode_t mode,
 518                         const struct file_operations *i_fop,
 519                         void *private)
 520 {
 521         int err;
 522
 523         err = __rpc_create_common(dir, dentry, S_IFREG | mode, i_fop, private);
 524         if (err)
 525                 return err;
 526         fsnotify_create(dir, dentry);
 527         return 0;
 528 }
 529
 530 static int __rpc_mkdir(struct inode *dir, struct dentry *dentry,
 531                        umode_t mode,
 532                        const struct file_operations *i_fop,
 533                        void *private)
 534 {
 535         int err;
 536
 537         err = __rpc_create_common(dir, dentry, S_IFDIR | mode, i_fop, private);
 538         if (err)
 539                 return err;
 540         inc_nlink(dir);
 541         fsnotify_mkdir(dir, dentry);
 542         return 0;
 543 }
 544
 545 static void
 546 init_pipe(struct rpc_pipe *pipe)
 547 {
 548         pipe->nreaders = 0;
 549         pipe->nwriters = 0;
 550         INIT_LIST_HEAD(&pipe->in_upcall);
 551         INIT_LIST_HEAD(&pipe->in_downcall);
 552         INIT_LIST_HEAD(&pipe->pipe);
 553         pipe->pipelen = 0;
 554         INIT_DELAYED_WORK(&pipe->queue_timeout,
 555                             rpc_timeout_upcall_queue);
 556         pipe->ops = NULL;
 557         spin_lock_init(&pipe->lock);
 558         pipe->dentry = NULL;
 559 }
 560
 561 void rpc_destroy_pipe_data(struct rpc_pipe *pipe)
 562 {
 563         kfree(pipe);
 564 }
 565 EXPORT_SYMBOL_GPL(rpc_destroy_pipe_data);
 566
 567 struct rpc_pipe *rpc_mkpipe_data(const struct rpc_pipe_ops *ops, int flags)
 568 {
 569         struct rpc_pipe *pipe;
 570
 571         pipe = kzalloc(sizeof(struct rpc_pipe), GFP_KERNEL);
 572         if (!pipe)
 573                 return ERR_PTR(-ENOMEM);
 574         init_pipe(pipe);
 575         pipe->ops = ops;
 576         pipe->flags = flags;
 577         return pipe;
 578 }
 579 EXPORT_SYMBOL_GPL(rpc_mkpipe_data);
 580
 581 static int __rpc_mkpipe_dentry(struct inode *dir, struct dentry *dentry,
 582                                umode_t mode,
 583                                const struct file_operations *i_fop,
 584                                void *private,
 585                                struct rpc_pipe *pipe)
 586 {
 587         struct rpc_inode *rpci;
 588         int err;
 589
 590         err = __rpc_create_common(dir, dentry, S_IFIFO | mode, i_fop, private);
 591         if (err)
 592                 return err;
 593         rpci = RPC_I(dentry->d_inode);
 594         rpci->private = private;
 595         rpci->pipe = pipe;
 596         fsnotify_create(dir, dentry);
 597         return 0;
 598 }
 599
 600 static int __rpc_rmdir(struct inode *dir, struct dentry *dentry)
 601 {
 602         int ret;
 603
 604         dget(dentry);
 605         ret = simple_rmdir(dir, dentry);
 606         d_delete(dentry);
 607         dput(dentry);
 608         return ret;
 609 }
 610
 611 int rpc_rmdir(struct dentry *dentry)
 612 {
 613         struct dentry *parent;
 614         struct inode *dir;
 615         int error;
 616
 617         parent = dget_parent(dentry);
 618         dir = parent->d_inode;
 619         mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
 620         error = __rpc_rmdir(dir, dentry);
 621         mutex_unlock(&dir->i_mutex);
 622         dput(parent);
 623         return error;
 624 }
 625 EXPORT_SYMBOL_GPL(rpc_rmdir);
 626
 627 static int __rpc_unlink(struct inode *dir, struct dentry *dentry)
 628 {
 629         int ret;
 630
 631         dget(dentry);
 632         ret = simple_unlink(dir, dentry);
 633         d_delete(dentry);
 634         dput(dentry);
 635         return ret;
 636 }
 637
 638 static int __rpc_rmpipe(struct inode *dir, struct dentry *dentry)
 639 {
 640         struct inode *inode = dentry->d_inode;
 641
 642         rpc_close_pipes(inode);
 643         return __rpc_unlink(dir, dentry);
 644 }
 645
 646 static struct dentry *__rpc_lookup_create_exclusive(struct dentry *parent,
 647                                           const char *name)
 648 {
 649         struct qstr q = QSTR_INIT(name, strlen(name));
 650         struct dentry *dentry = d_hash_and_lookup(parent, &q);
 651         if (!dentry) {
 652                 dentry = d_alloc(parent, &q);
 653                 if (!dentry)
 654                         return ERR_PTR(-ENOMEM);
 655         }
 656         if (dentry->d_inode == NULL)
 657                 return dentry;
 658         dput(dentry);
 659         return ERR_PTR(-EEXIST);
 660 }
 661
 662 /*
 663  * FIXME: This probably has races.
 664  */
 665 static void __rpc_depopulate(struct dentry *parent,
 666                              const struct rpc_filelist *files,
 667                              int start, int eof)
 668 {
 669         struct inode *dir = parent->d_inode;
 670         struct dentry *dentry;
 671         struct qstr name;
 672         int i;
 673
 674         for (i = start; i < eof; i++) {
 675                 name.name = files[i].name;
 676                 name.len = strlen(files[i].name);
 677                 dentry = d_hash_and_lookup(parent, &name);
 678
 679                 if (dentry == NULL)
 680                         continue;
 681                 if (dentry->d_inode == NULL)
 682                         goto next;
 683                 switch (dentry->d_inode->i_mode & S_IFMT) {
 684                         default:
 685                                 BUG();
 686                         case S_IFREG:
 687                                 __rpc_unlink(dir, dentry);
 688                                 break;
 689                         case S_IFDIR:
 690                                 __rpc_rmdir(dir, dentry);
 691                 }
 692 next:
 693                 dput(dentry);
 694         }
 695 }
 696
 697 static void rpc_depopulate(struct dentry *parent,
 698                            const struct rpc_filelist *files,
 699                            int start, int eof)
 700 {
 701         struct inode *dir = parent->d_inode;
 702
 703         mutex_lock_nested(&dir->i_mutex, I_MUTEX_CHILD);
 704         __rpc_depopulate(parent, files, start, eof);
 705         mutex_unlock(&dir->i_mutex);
 706 }
 707
 708 static int rpc_populate(struct dentry *parent,
 709                         const struct rpc_filelist *files,
 710                         int start, int eof,
 711                         void *private)
 712 {
 713         struct inode *dir = parent->d_inode;
 714         struct dentry *dentry;
 715         int i, err;
 716
 717         mutex_lock(&dir->i_mutex);
 718         for (i = start; i < eof; i++) {
 719                 dentry = __rpc_lookup_create_exclusive(parent, files[i].name);
 720                 err = PTR_ERR(dentry);
 721                 if (IS_ERR(dentry))
 722                         goto out_bad;
 723                 switch (files[i].mode & S_IFMT) {
 724                         default:
 725                                 BUG();
 726                         case S_IFREG:
 727                                 err = __rpc_create(dir, dentry,
 728                                                 files[i].mode,
 729                                                 files[i].i_fop,
 730                                                 private);
 731                                 break;
 732                         case S_IFDIR:
 733                                 err = __rpc_mkdir(dir, dentry,
 734                                                 files[i].mode,
 735                                                 NULL,
 736                                                 private);
 737                 }
 738                 if (err != 0)
 739                         goto out_bad;
 740         }
 741         mutex_unlock(&dir->i_mutex);
 742         return 0;
 743 out_bad:
 744         __rpc_depopulate(parent, files, start, eof);
 745         mutex_unlock(&dir->i_mutex);
 746         printk(KERN_WARNING "%s: %s failed to populate directory %pd\n",
 747                         __FILE__, __func__, parent);
 748         return err;
 749 }
 750
 751 static struct dentry *rpc_mkdir_populate(struct dentry *parent,
 752                 const char *name, umode_t mode, void *private,
 753                 int (*populate)(struct dentry *, void *), void *args_populate)
 754 {
 755         struct dentry *dentry;
 756         struct inode *dir = parent->d_inode;
 757         int error;
 758
 759         mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
 760         dentry = __rpc_lookup_create_exclusive(parent, name);
 761         if (IS_ERR(dentry))
 762                 goto out;
 763         error = __rpc_mkdir(dir, dentry, mode, NULL, private);
 764         if (error != 0)
 765                 goto out_err;
 766         if (populate != NULL) {
 767                 error = populate(dentry, args_populate);
 768                 if (error)
 769                         goto err_rmdir;
 770         }
 771 out:
 772         mutex_unlock(&dir->i_mutex);
 773         return dentry;
 774 err_rmdir:
 775         __rpc_rmdir(dir, dentry);
 776 out_err:
 777         dentry = ERR_PTR(error);
 778         goto out;
 779 }
 780
 781 static int rpc_rmdir_depopulate(struct dentry *dentry,
 782                 void (*depopulate)(struct dentry *))
 783 {
 784         struct dentry *parent;
 785         struct inode *dir;
 786         int error;
 787
 788         parent = dget_parent(dentry);
 789         dir = parent->d_inode;
 790         mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
 791         if (depopulate != NULL)
 792                 depopulate(dentry);
 793         error = __rpc_rmdir(dir, dentry);
 794         mutex_unlock(&dir->i_mutex);
 795         dput(parent);
 796         return error;
 797 }
 798
 799 /**
 800  * rpc_mkpipe - make an rpc_pipefs file for kernel<->userspace communication
 801  * @parent: dentry of directory to create new "pipe" in
 802  * @name: name of pipe
 803  * @private: private data to associate with the pipe, for the caller's use
 804  * @pipe: &rpc_pipe containing input parameters
 805  *
 806  * Data is made available for userspace to read by calls to
 807  * rpc_queue_upcall().  The actual reads will result in calls to
 808  * @ops->upcall, which will be called with the file pointer,
 809  * message, and userspace buffer to copy to.
 810  *
 811  * Writes can come at any time, and do not necessarily have to be
 812  * responses to upcalls.  They will result in calls to @msg->downcall.
 813  *
 814  * The @private argument passed here will be available to all these methods
 815  * from the file pointer, via RPC_I(file_inode(file))->private.
 816  */
 817 struct dentry *rpc_mkpipe_dentry(struct dentry *parent, const char *name,
 818                                  void *private, struct rpc_pipe *pipe)
 819 {
 820         struct dentry *dentry;
 821         struct inode *dir = parent->d_inode;
 822         umode_t umode = S_IFIFO | S_IRUSR | S_IWUSR;
 823         int err;
 824
 825         if (pipe->ops->upcall == NULL)
 826                 umode &= ~S_IRUGO;
 827         if (pipe->ops->downcall == NULL)
 828                 umode &= ~S_IWUGO;
 829
 830         mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
 831         dentry = __rpc_lookup_create_exclusive(parent, name);
 832         if (IS_ERR(dentry))
 833                 goto out;
 834         err = __rpc_mkpipe_dentry(dir, dentry, umode, &rpc_pipe_fops,
 835                                   private, pipe);
 836         if (err)
 837                 goto out_err;
 838 out:
 839         mutex_unlock(&dir->i_mutex);
 840         return dentry;
 841 out_err:
 842         dentry = ERR_PTR(err);
 843         printk(KERN_WARNING "%s: %s() failed to create pipe %pd/%s (errno = %d)\n",
 844                         __FILE__, __func__, parent, name,
 845                         err);
 846         goto out;
 847 }
 848 EXPORT_SYMBOL_GPL(rpc_mkpipe_dentry);
 849
 850 /**
 851  * rpc_unlink - remove a pipe
 852  * @dentry: dentry for the pipe, as returned from rpc_mkpipe
 853  *
 854  * After this call, lookups will no longer find the pipe, and any
 855  * attempts to read or write using preexisting opens of the pipe will
 856  * return -EPIPE.
 857  */
 858 int
 859 rpc_unlink(struct dentry *dentry)
 860 {
 861         struct dentry *parent;
 862         struct inode *dir;
 863         int error = 0;
 864
 865         parent = dget_parent(dentry);
 866         dir = parent->d_inode;
 867         mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
 868         error = __rpc_rmpipe(dir, dentry);
 869         mutex_unlock(&dir->i_mutex);
 870         dput(parent);
 871         return error;
 872 }
 873 EXPORT_SYMBOL_GPL(rpc_unlink);
 874
 875 /**
 876  * rpc_init_pipe_dir_head - initialise a struct rpc_pipe_dir_head
 877  * @pdh: pointer to struct rpc_pipe_dir_head
 878  */
 879 void rpc_init_pipe_dir_head(struct rpc_pipe_dir_head *pdh)
 880 {
 881         INIT_LIST_HEAD(&pdh->pdh_entries);
 882         pdh->pdh_dentry = NULL;
 883 }
 884 EXPORT_SYMBOL_GPL(rpc_init_pipe_dir_head);
 885
 886 /**
 887  * rpc_init_pipe_dir_object - initialise a struct rpc_pipe_dir_object
 888  * @pdo: pointer to struct rpc_pipe_dir_object
 889  * @pdo_ops: pointer to const struct rpc_pipe_dir_object_ops
 890  * @pdo_data: pointer to caller-defined data
 891  */
 892 void rpc_init_pipe_dir_object(struct rpc_pipe_dir_object *pdo,
 893                 const struct rpc_pipe_dir_object_ops *pdo_ops,
 894                 void *pdo_data)
 895 {
 896         INIT_LIST_HEAD(&pdo->pdo_head);
 897         pdo->pdo_ops = pdo_ops;
 898         pdo->pdo_data = pdo_data;
 899 }
 900 EXPORT_SYMBOL_GPL(rpc_init_pipe_dir_object);
 901
 902 static int
 903 rpc_add_pipe_dir_object_locked(struct net *net,
 904                 struct rpc_pipe_dir_head *pdh,
 905                 struct rpc_pipe_dir_object *pdo)
 906 {
 907         int ret = 0;
 908
 909         if (pdh->pdh_dentry)
 910                 ret = pdo->pdo_ops->create(pdh->pdh_dentry, pdo);
 911         if (ret == 0)
 912                 list_add_tail(&pdo->pdo_head, &pdh->pdh_entries);
 913         return ret;
 914 }
 915
 916 static void
 917 rpc_remove_pipe_dir_object_locked(struct net *net,
 918                 struct rpc_pipe_dir_head *pdh,
 919                 struct rpc_pipe_dir_object *pdo)
 920 {
 921         if (pdh->pdh_dentry)
 922                 pdo->pdo_ops->destroy(pdh->pdh_dentry, pdo);
 923         list_del_init(&pdo->pdo_head);
 924 }
 925
 926 /**
 927  * rpc_add_pipe_dir_object - associate a rpc_pipe_dir_object to a directory
 928  * @net: pointer to struct net
 929  * @pdh: pointer to struct rpc_pipe_dir_head
 930  * @pdo: pointer to struct rpc_pipe_dir_object
 931  *
 932  */
 933 int
 934 rpc_add_pipe_dir_object(struct net *net,
 935                 struct rpc_pipe_dir_head *pdh,
 936                 struct rpc_pipe_dir_object *pdo)
 937 {
 938         int ret = 0;
 939
 940         if (list_empty(&pdo->pdo_head)) {
 941                 struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
 942
 943                 mutex_lock(&sn->pipefs_sb_lock);
 944                 ret = rpc_add_pipe_dir_object_locked(net, pdh, pdo);
 945                 mutex_unlock(&sn->pipefs_sb_lock);
 946         }
 947         return ret;
 948 }
 949 EXPORT_SYMBOL_GPL(rpc_add_pipe_dir_object);
 950
 951 /**
 952  * rpc_remove_pipe_dir_object - remove a rpc_pipe_dir_object from a directory
 953  * @net: pointer to struct net
 954  * @pdh: pointer to struct rpc_pipe_dir_head
 955  * @pdo: pointer to struct rpc_pipe_dir_object
 956  *
 957  */
 958 void
 959 rpc_remove_pipe_dir_object(struct net *net,
 960                 struct rpc_pipe_dir_head *pdh,
 961                 struct rpc_pipe_dir_object *pdo)
 962 {
 963         if (!list_empty(&pdo->pdo_head)) {
 964                 struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
 965
 966                 mutex_lock(&sn->pipefs_sb_lock);
 967                 rpc_remove_pipe_dir_object_locked(net, pdh, pdo);
 968                 mutex_unlock(&sn->pipefs_sb_lock);
 969         }
 970 }
 971 EXPORT_SYMBOL_GPL(rpc_remove_pipe_dir_object);
 972
 973 /**
 974  * rpc_find_or_alloc_pipe_dir_object
 975  * @net: pointer to struct net
 976  * @pdh: pointer to struct rpc_pipe_dir_head
 977  * @match: match struct rpc_pipe_dir_object to data
 978  * @alloc: allocate a new struct rpc_pipe_dir_object
 979  * @data: user defined data for match() and alloc()
 980  *
 981  */
 982 struct rpc_pipe_dir_object *
 983 rpc_find_or_alloc_pipe_dir_object(struct net *net,
 984                 struct rpc_pipe_dir_head *pdh,
 985                 int (*match)(struct rpc_pipe_dir_object *, void *),
 986                 struct rpc_pipe_dir_object *(*alloc)(void *),
 987                 void *data)
 988 {
 989         struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
 990         struct rpc_pipe_dir_object *pdo;
 991
 992         mutex_lock(&sn->pipefs_sb_lock);
 993         list_for_each_entry(pdo, &pdh->pdh_entries, pdo_head) {
 994                 if (!match(pdo, data))
 995                         continue;
 996                 goto out;
 997         }
 998         pdo = alloc(data);
 999         if (!pdo)
1000                 goto out;
1001         rpc_add_pipe_dir_object_locked(net, pdh, pdo);
1002 out:
1003         mutex_unlock(&sn->pipefs_sb_lock);
1004         return pdo;
1005 }
1006 EXPORT_SYMBOL_GPL(rpc_find_or_alloc_pipe_dir_object);
1007
1008 static void
1009 rpc_create_pipe_dir_objects(struct rpc_pipe_dir_head *pdh)
1010 {
1011         struct rpc_pipe_dir_object *pdo;
1012         struct dentry *dir = pdh->pdh_dentry;
1013
1014         list_for_each_entry(pdo, &pdh->pdh_entries, pdo_head)
1015                 pdo->pdo_ops->create(dir, pdo);
1016 }
1017
1018 static void
1019 rpc_destroy_pipe_dir_objects(struct rpc_pipe_dir_head *pdh)
1020 {
1021         struct rpc_pipe_dir_object *pdo;
1022         struct dentry *dir = pdh->pdh_dentry;
1023
1024         list_for_each_entry(pdo, &pdh->pdh_entries, pdo_head)
1025                 pdo->pdo_ops->destroy(dir, pdo);
1026 }
1027
1028 enum {
1029         RPCAUTH_info,
1030         RPCAUTH_EOF
1031 };
1032
1033 static const struct rpc_filelist authfiles[] = {
1034         [RPCAUTH_info] = {
1035                 .name = "info",
1036                 .i_fop = &rpc_info_operations,
1037                 .mode = S_IFREG | S_IRUSR,
1038         },
1039 };
1040
1041 static int rpc_clntdir_populate(struct dentry *dentry, void *private)
1042 {
1043         return rpc_populate(dentry,
1044                             authfiles, RPCAUTH_info, RPCAUTH_EOF,
1045                             private);
1046 }
1047
1048 static void rpc_clntdir_depopulate(struct dentry *dentry)
1049 {
1050         rpc_depopulate(dentry, authfiles, RPCAUTH_info, RPCAUTH_EOF);
1051 }
1052
1053 /**
1054  * rpc_create_client_dir - Create a new rpc_client directory in rpc_pipefs
1055  * @dentry: the parent of new directory
1056  * @name: the name of new directory
1057  * @rpc_client: rpc client to associate with this directory
1058  *
1059  * This creates a directory at the given @path associated with
1060  * @rpc_clnt, which will contain a file named "info" with some basic
1061  * information about the client, together with any "pipes" that may
1062  * later be created using rpc_mkpipe().
1063  */
1064 struct dentry *rpc_create_client_dir(struct dentry *dentry,
1065                                    const char *name,
1066                                    struct rpc_clnt *rpc_client)
1067 {
1068         struct dentry *ret;
1069
1070         ret = rpc_mkdir_populate(dentry, name, S_IRUGO | S_IXUGO, NULL,
1071                         rpc_clntdir_populate, rpc_client);
1072         if (!IS_ERR(ret)) {
1073                 rpc_client->cl_pipedir_objects.pdh_dentry = ret;
1074                 rpc_create_pipe_dir_objects(&rpc_client->cl_pipedir_objects);
1075         }
1076         return ret;
1077 }
1078
1079 /**
1080  * rpc_remove_client_dir - Remove a directory created with rpc_create_client_dir()
1081  * @rpc_client: rpc_client for the pipe
1082  */
1083 int rpc_remove_client_dir(struct rpc_clnt *rpc_client)
1084 {
1085         struct dentry *dentry = rpc_client->cl_pipedir_objects.pdh_dentry;
1086
1087         if (dentry == NULL)
1088                 return 0;
1089         rpc_destroy_pipe_dir_objects(&rpc_client->cl_pipedir_objects);
1090         rpc_client->cl_pipedir_objects.pdh_dentry = NULL;
1091         return rpc_rmdir_depopulate(dentry, rpc_clntdir_depopulate);
1092 }
1093
1094 static const struct rpc_filelist cache_pipefs_files[3] = {
1095         [0] = {
1096                 .name = "channel",
1097                 .i_fop = &cache_file_operations_pipefs,
1098                 .mode = S_IFREG|S_IRUSR|S_IWUSR,
1099         },
1100         [1] = {
1101                 .name = "content",
1102                 .i_fop = &content_file_operations_pipefs,
1103                 .mode = S_IFREG|S_IRUSR,
1104         },
1105         [2] = {
1106                 .name = "flush",
1107                 .i_fop = &cache_flush_operations_pipefs,
1108                 .mode = S_IFREG|S_IRUSR|S_IWUSR,
1109         },
1110 };
1111
1112 static int rpc_cachedir_populate(struct dentry *dentry, void *private)
1113 {
1114         return rpc_populate(dentry,
1115                             cache_pipefs_files, 0, 3,
1116                             private);
1117 }
1118
1119 static void rpc_cachedir_depopulate(struct dentry *dentry)
1120 {
1121         rpc_depopulate(dentry, cache_pipefs_files, 0, 3);
1122 }
1123
1124 struct dentry *rpc_create_cache_dir(struct dentry *parent, const char *name,
1125                                     umode_t umode, struct cache_detail *cd)
1126 {
1127         return rpc_mkdir_populate(parent, name, umode, NULL,
1128                         rpc_cachedir_populate, cd);
1129 }
1130
1131 void rpc_remove_cache_dir(struct dentry *dentry)
1132 {
1133         rpc_rmdir_depopulate(dentry, rpc_cachedir_depopulate);
1134 }
1135
1136 /*
1137  * populate the filesystem
1138  */
1139 static const struct super_operations s_ops = {
1140         .alloc_inode    = rpc_alloc_inode,
1141         .destroy_inode  = rpc_destroy_inode,
1142         .statfs         = simple_statfs,
1143 };
1144
1145 #define RPCAUTH_GSSMAGIC 0x67596969
1146
1147 /*
1148  * We have a single directory with 1 node in it.
1149  */
1150 enum {
1151         RPCAUTH_lockd,
1152         RPCAUTH_mount,
1153         RPCAUTH_nfs,
1154         RPCAUTH_portmap,
1155         RPCAUTH_statd,
1156         RPCAUTH_nfsd4_cb,
1157         RPCAUTH_cache,
1158         RPCAUTH_nfsd,
1159         RPCAUTH_gssd,
1160         RPCAUTH_RootEOF
1161 };
1162
1163 static const struct rpc_filelist files[] = {
1164         [RPCAUTH_lockd] = {
1165                 .name = "lockd",
1166                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
1167         },
1168         [RPCAUTH_mount] = {
1169                 .name = "mount",
1170                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
1171         },
1172         [RPCAUTH_nfs] = {
1173                 .name = "nfs",
1174                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
1175         },
1176         [RPCAUTH_portmap] = {
1177                 .name = "portmap",
1178                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
1179         },
1180         [RPCAUTH_statd] = {
1181                 .name = "statd",
1182                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
1183         },
1184         [RPCAUTH_nfsd4_cb] = {
1185                 .name = "nfsd4_cb",
1186                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
1187         },
1188         [RPCAUTH_cache] = {
1189                 .name = "cache",
1190                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
1191         },
1192         [RPCAUTH_nfsd] = {
1193                 .name = "nfsd",
1194                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
1195         },
1196         [RPCAUTH_gssd] = {
1197                 .name = "gssd",
1198                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
1199         },
1200 };
1201
1202 /*
1203  * This call can be used only in RPC pipefs mount notification hooks.
1204  */
1205 struct dentry *rpc_d_lookup_sb(const struct super_block *sb,
1206                                const unsigned char *dir_name)
1207 {
1208         struct qstr dir = QSTR_INIT(dir_name, strlen(dir_name));
1209         return d_hash_and_lookup(sb->s_root, &dir);
1210 }
1211 EXPORT_SYMBOL_GPL(rpc_d_lookup_sb);
1212
1213 int rpc_pipefs_init_net(struct net *net)
1214 {
1215         struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
1216
1217         sn->gssd_dummy = rpc_mkpipe_data(&gssd_dummy_pipe_ops, 0);
1218         if (IS_ERR(sn->gssd_dummy))
1219                 return PTR_ERR(sn->gssd_dummy);
1220
1221         mutex_init(&sn->pipefs_sb_lock);
1222         sn->pipe_version = -1;
1223         return 0;
1224 }
1225
1226 void rpc_pipefs_exit_net(struct net *net)
1227 {
1228         struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
1229
1230         rpc_destroy_pipe_data(sn->gssd_dummy);
1231 }
1232
1233 /*
1234  * This call will be used for per network namespace operations calls.
1235  * Note: Function will be returned with pipefs_sb_lock taken if superblock was
1236  * found. This lock have to be released by rpc_put_sb_net() when all operations
1237  * will be completed.
1238  */
1239 struct super_block *rpc_get_sb_net(const struct net *net)
1240 {
1241         struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
1242
1243         mutex_lock(&sn->pipefs_sb_lock);
1244         if (sn->pipefs_sb)
1245                 return sn->pipefs_sb;
1246         mutex_unlock(&sn->pipefs_sb_lock);
1247         return NULL;
1248 }
1249 EXPORT_SYMBOL_GPL(rpc_get_sb_net);
1250
1251 void rpc_put_sb_net(const struct net *net)
1252 {
1253         struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
1254
1255         WARN_ON(sn->pipefs_sb == NULL);
1256         mutex_unlock(&sn->pipefs_sb_lock);
1257 }
1258 EXPORT_SYMBOL_GPL(rpc_put_sb_net);
1259
1260 static const struct rpc_filelist gssd_dummy_clnt_dir[] = {
1261         [0] = {
1262                 .name = "clntXX",
1263                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
1264         },
1265 };
1266
1267 static ssize_t
1268 dummy_downcall(struct file *filp, const char __user *src, size_t len)
1269 {
1270         return -EINVAL;
1271 }
1272
1273 static const struct rpc_pipe_ops gssd_dummy_pipe_ops = {
1274         .upcall         = rpc_pipe_generic_upcall,
1275         .downcall       = dummy_downcall,
1276 };
1277
1278 /**
1279  * rpc_gssd_dummy_populate - create a dummy gssd pipe
1280  * @root:       root of the rpc_pipefs filesystem
1281  * @pipe_data:  pipe data created when netns is initialized
1282  *
1283  * Create a dummy set of directories and a pipe that gssd can hold open to
1284  * indicate that it is up and running.
1285  */
1286 static struct dentry *
1287 rpc_gssd_dummy_populate(struct dentry *root, struct rpc_pipe *pipe_data)
1288 {
1289         int ret = 0;
1290         struct dentry *gssd_dentry;
1291         struct dentry *clnt_dentry = NULL;
1292         struct dentry *pipe_dentry = NULL;
1293         struct qstr q = QSTR_INIT(files[RPCAUTH_gssd].name,
1294                                   strlen(files[RPCAUTH_gssd].name));
1295
1296         /* We should never get this far if "gssd" doesn't exist */
1297         gssd_dentry = d_hash_and_lookup(root, &q);
1298         if (!gssd_dentry)
1299                 return ERR_PTR(-ENOENT);
1300
1301         ret = rpc_populate(gssd_dentry, gssd_dummy_clnt_dir, 0, 1, NULL);
1302         if (ret) {
1303                 pipe_dentry = ERR_PTR(ret);
1304                 goto out;
1305         }
1306
1307         q.name = gssd_dummy_clnt_dir[0].name;
1308         q.len = strlen(gssd_dummy_clnt_dir[0].name);
1309         clnt_dentry = d_hash_and_lookup(gssd_dentry, &q);
1310         if (!clnt_dentry) {
1311                 pipe_dentry = ERR_PTR(-ENOENT);
1312                 goto out;
1313         }
1314
1315         pipe_dentry = rpc_mkpipe_dentry(clnt_dentry, "gssd", NULL, pipe_data);
1316         if (IS_ERR(pipe_dentry))
1317                 __rpc_depopulate(gssd_dentry, gssd_dummy_clnt_dir, 0, 1);
1318 out:
1319         dput(clnt_dentry);
1320         dput(gssd_dentry);
1321         return pipe_dentry;
1322 }
1323
1324 static int
1325 rpc_fill_super(struct super_block *sb, void *data, int silent)
1326 {
1327         struct inode *inode;
1328         struct dentry *root, *gssd_dentry;
1329         struct net *net = data;
1330         struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
1331         int err;
1332
1333         sb->s_blocksize = PAGE_CACHE_SIZE;
1334         sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
1335         sb->s_magic = RPCAUTH_GSSMAGIC;
1336         sb->s_op = &s_ops;
1337         sb->s_d_op = &simple_dentry_operations;
1338         sb->s_time_gran = 1;
1339
1340         inode = rpc_get_inode(sb, S_IFDIR | S_IRUGO | S_IXUGO);
1341         sb->s_root = root = d_make_root(inode);
1342         if (!root)
1343                 return -ENOMEM;
1344         if (rpc_populate(root, files, RPCAUTH_lockd, RPCAUTH_RootEOF, NULL))
1345                 return -ENOMEM;
1346
1347         gssd_dentry = rpc_gssd_dummy_populate(root, sn->gssd_dummy);
1348         if (IS_ERR(gssd_dentry)) {
1349                 __rpc_depopulate(root, files, RPCAUTH_lockd, RPCAUTH_RootEOF);
1350                 return PTR_ERR(gssd_dentry);
1351         }
1352
1353         dprintk("RPC:       sending pipefs MOUNT notification for net %p%s\n",
1354                 net, NET_NAME(net));
1355         mutex_lock(&sn->pipefs_sb_lock);
1356         sn->pipefs_sb = sb;
1357         err = blocking_notifier_call_chain(&rpc_pipefs_notifier_list,
1358                                            RPC_PIPEFS_MOUNT,
1359                                            sb);
1360         if (err)
1361                 goto err_depopulate;
1362         sb->s_fs_info = get_net(net);
1363         mutex_unlock(&sn->pipefs_sb_lock);
1364         return 0;
1365
1366 err_depopulate:
1367         dput(gssd_dentry);
1368         blocking_notifier_call_chain(&rpc_pipefs_notifier_list,
1369                                            RPC_PIPEFS_UMOUNT,
1370                                            sb);
1371         sn->pipefs_sb = NULL;
1372         __rpc_depopulate(root, files, RPCAUTH_lockd, RPCAUTH_RootEOF);
1373         mutex_unlock(&sn->pipefs_sb_lock);
1374         return err;
1375 }
1376
1377 bool
1378 gssd_running(struct net *net)
1379 {
1380         struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
1381         struct rpc_pipe *pipe = sn->gssd_dummy;
1382
1383         return pipe->nreaders || pipe->nwriters;
1384 }
1385 EXPORT_SYMBOL_GPL(gssd_running);
1386
1387 static struct dentry *
1388 rpc_mount(struct file_system_type *fs_type,
1389                 int flags, const char *dev_name, void *data)
1390 {
1391         return mount_ns(fs_type, flags, current->nsproxy->net_ns, rpc_fill_super);
1392 }
1393
1394 static void rpc_kill_sb(struct super_block *sb)
1395 {
1396         struct net *net = sb->s_fs_info;
1397         struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
1398
1399         mutex_lock(&sn->pipefs_sb_lock);
1400         if (sn->pipefs_sb != sb) {
1401                 mutex_unlock(&sn->pipefs_sb_lock);
1402                 goto out;
1403         }
1404         sn->pipefs_sb = NULL;
1405         dprintk("RPC:       sending pipefs UMOUNT notification for net %p%s\n",
1406                 net, NET_NAME(net));
1407         blocking_notifier_call_chain(&rpc_pipefs_notifier_list,
1408                                            RPC_PIPEFS_UMOUNT,
1409                                            sb);
1410         mutex_unlock(&sn->pipefs_sb_lock);
1411         put_net(net);
1412 out:
1413         kill_litter_super(sb);
1414 }
1415
1416 static struct file_system_type rpc_pipe_fs_type = {
1417         .owner          = THIS_MODULE,
1418         .name           = "rpc_pipefs",
1419         .mount          = rpc_mount,
1420         .kill_sb        = rpc_kill_sb,
1421 };
1422 MODULE_ALIAS_FS("rpc_pipefs");
1423 MODULE_ALIAS("rpc_pipefs");
1424
1425 static void
1426 init_once(void *foo)
1427 {
1428         struct rpc_inode *rpci = (struct rpc_inode *) foo;
1429
1430         inode_init_once(&rpci->vfs_inode);
1431         rpci->private = NULL;
1432         rpci->pipe = NULL;
1433         init_waitqueue_head(&rpci->waitq);
1434 }
1435
1436 int register_rpc_pipefs(void)
1437 {
1438         int err;
1439
1440         rpc_inode_cachep = kmem_cache_create("rpc_inode_cache",
1441                                 sizeof(struct rpc_inode),
1442                                 0, (SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT|
1443                                                 SLAB_MEM_SPREAD),
1444                                 init_once);
1445         if (!rpc_inode_cachep)
1446                 return -ENOMEM;
1447         err = rpc_clients_notifier_register();
1448         if (err)
1449                 goto err_notifier;
1450         err = register_filesystem(&rpc_pipe_fs_type);
1451         if (err)
1452                 goto err_register;
1453         return 0;
1454
1455 err_register:
1456         rpc_clients_notifier_unregister();
1457 err_notifier:
1458         kmem_cache_destroy(rpc_inode_cachep);
1459         return err;
1460 }
1461
1462 void unregister_rpc_pipefs(void)
1463 {
1464         rpc_clients_notifier_unregister();
1465         kmem_cache_destroy(rpc_inode_cachep);
1466         unregister_filesystem(&rpc_pipe_fs_type);
1467 }