net/sunrpc/rpc_pipe.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * net/sunrpc/rpc_pipe.c
   4  *
   5  * Userland/kernel interface for rpcauth_gss.
   6  * Code shamelessly plagiarized from fs/nfsd/nfsctl.c
   7  * and fs/sysfs/inode.c
   8  *
   9  * Copyright (c) 2002, Trond Myklebust <trond.myklebust@fys.uio.no>
  10  *
  11  */
  12 #include <linux/module.h>
  13 #include <linux/slab.h>
  14 #include <linux/string.h>
  15 #include <linux/pagemap.h>
  16 #include <linux/mount.h>
  17 #include <linux/fs_context.h>
  18 #include <linux/namei.h>
  19 #include <linux/fsnotify.h>
  20 #include <linux/kernel.h>
  21 #include <linux/rcupdate.h>
  22 #include <linux/utsname.h>
  23
  24 #include <asm/ioctls.h>
  25 #include <linux/poll.h>
  26 #include <linux/wait.h>
  27 #include <linux/seq_file.h>
  28
  29 #include <linux/sunrpc/clnt.h>
  30 #include <linux/workqueue.h>
  31 #include <linux/sunrpc/rpc_pipe_fs.h>
  32 #include <linux/sunrpc/cache.h>
  33 #include <linux/nsproxy.h>
  34 #include <linux/notifier.h>
  35
  36 #include "netns.h"
  37 #include "sunrpc.h"
  38
  39 #define RPCDBG_FACILITY RPCDBG_DEBUG
  40
  41 #define NET_NAME(net)   ((net == &init_net) ? " (init_net)" : "")
  42
  43 static struct file_system_type rpc_pipe_fs_type;
  44 static const struct rpc_pipe_ops gssd_dummy_pipe_ops;
  45
  46 static struct kmem_cache *rpc_inode_cachep __read_mostly;
  47
  48 #define RPC_UPCALL_TIMEOUT (30*HZ)
  49
  50 static BLOCKING_NOTIFIER_HEAD(rpc_pipefs_notifier_list);
  51
  52 int rpc_pipefs_notifier_register(struct notifier_block *nb)
  53 {
  54         return blocking_notifier_chain_register(&rpc_pipefs_notifier_list, nb);
  55 }
  56 EXPORT_SYMBOL_GPL(rpc_pipefs_notifier_register);
  57
  58 void rpc_pipefs_notifier_unregister(struct notifier_block *nb)
  59 {
  60         blocking_notifier_chain_unregister(&rpc_pipefs_notifier_list, nb);
  61 }
  62 EXPORT_SYMBOL_GPL(rpc_pipefs_notifier_unregister);
  63
  64 static void rpc_purge_list(wait_queue_head_t *waitq, struct list_head *head,
  65                 void (*destroy_msg)(struct rpc_pipe_msg *), int err)
  66 {
  67         struct rpc_pipe_msg *msg;
  68
  69         if (list_empty(head))
  70                 return;
  71         do {
  72                 msg = list_entry(head->next, struct rpc_pipe_msg, list);
  73                 list_del_init(&msg->list);
  74                 msg->errno = err;
  75                 destroy_msg(msg);
  76         } while (!list_empty(head));
  77
  78         if (waitq)
  79                 wake_up(waitq);
  80 }
  81
  82 static void
  83 rpc_timeout_upcall_queue(struct work_struct *work)
  84 {
  85         LIST_HEAD(free_list);
  86         struct rpc_pipe *pipe =
  87                 container_of(work, struct rpc_pipe, queue_timeout.work);
  88         void (*destroy_msg)(struct rpc_pipe_msg *);
  89         struct dentry *dentry;
  90
  91         spin_lock(&pipe->lock);
  92         destroy_msg = pipe->ops->destroy_msg;
  93         if (pipe->nreaders == 0) {
  94                 list_splice_init(&pipe->pipe, &free_list);
  95                 pipe->pipelen = 0;
  96         }
  97         dentry = dget(pipe->dentry);
  98         spin_unlock(&pipe->lock);
  99         rpc_purge_list(dentry ? &RPC_I(d_inode(dentry))->waitq : NULL,
 100                         &free_list, destroy_msg, -ETIMEDOUT);
 101         dput(dentry);
 102 }
 103
 104 ssize_t rpc_pipe_generic_upcall(struct file *filp, struct rpc_pipe_msg *msg,
 105                                 char __user *dst, size_t buflen)
 106 {
 107         char *data = (char *)msg->data + msg->copied;
 108         size_t mlen = min(msg->len - msg->copied, buflen);
 109         unsigned long left;
 110
 111         left = copy_to_user(dst, data, mlen);
 112         if (left == mlen) {
 113                 msg->errno = -EFAULT;
 114                 return -EFAULT;
 115         }
 116
 117         mlen -= left;
 118         msg->copied += mlen;
 119         msg->errno = 0;
 120         return mlen;
 121 }
 122 EXPORT_SYMBOL_GPL(rpc_pipe_generic_upcall);
 123
 124 /**
 125  * rpc_queue_upcall - queue an upcall message to userspace
 126  * @pipe: upcall pipe on which to queue given message
 127  * @msg: message to queue
 128  *
 129  * Call with an @inode created by rpc_mkpipe() to queue an upcall.
 130  * A userspace process may then later read the upcall by performing a
 131  * read on an open file for this inode.  It is up to the caller to
 132  * initialize the fields of @msg (other than @msg->list) appropriately.
 133  */
 134 int
 135 rpc_queue_upcall(struct rpc_pipe *pipe, struct rpc_pipe_msg *msg)
 136 {
 137         int res = -EPIPE;
 138         struct dentry *dentry;
 139
 140         spin_lock(&pipe->lock);
 141         if (pipe->nreaders) {
 142                 list_add_tail(&msg->list, &pipe->pipe);
 143                 pipe->pipelen += msg->len;
 144                 res = 0;
 145         } else if (pipe->flags & RPC_PIPE_WAIT_FOR_OPEN) {
 146                 if (list_empty(&pipe->pipe))
 147                         queue_delayed_work(rpciod_workqueue,
 148                                         &pipe->queue_timeout,
 149                                         RPC_UPCALL_TIMEOUT);
 150                 list_add_tail(&msg->list, &pipe->pipe);
 151                 pipe->pipelen += msg->len;
 152                 res = 0;
 153         }
 154         dentry = dget(pipe->dentry);
 155         spin_unlock(&pipe->lock);
 156         if (dentry) {
 157                 wake_up(&RPC_I(d_inode(dentry))->waitq);
 158                 dput(dentry);
 159         }
 160         return res;
 161 }
 162 EXPORT_SYMBOL_GPL(rpc_queue_upcall);
 163
 164 static inline void
 165 rpc_inode_setowner(struct inode *inode, void *private)
 166 {
 167         RPC_I(inode)->private = private;
 168 }
 169
 170 static void
 171 rpc_close_pipes(struct inode *inode)
 172 {
 173         struct rpc_pipe *pipe = RPC_I(inode)->pipe;
 174         int need_release;
 175         LIST_HEAD(free_list);
 176
 177         inode_lock(inode);
 178         spin_lock(&pipe->lock);
 179         need_release = pipe->nreaders != 0 || pipe->nwriters != 0;
 180         pipe->nreaders = 0;
 181         list_splice_init(&pipe->in_upcall, &free_list);
 182         list_splice_init(&pipe->pipe, &free_list);
 183         pipe->pipelen = 0;
 184         pipe->dentry = NULL;
 185         spin_unlock(&pipe->lock);
 186         rpc_purge_list(&RPC_I(inode)->waitq, &free_list, pipe->ops->destroy_msg, -EPIPE);
 187         pipe->nwriters = 0;
 188         if (need_release && pipe->ops->release_pipe)
 189                 pipe->ops->release_pipe(inode);
 190         cancel_delayed_work_sync(&pipe->queue_timeout);
 191         rpc_inode_setowner(inode, NULL);
 192         RPC_I(inode)->pipe = NULL;
 193         inode_unlock(inode);
 194 }
 195
 196 static struct inode *
 197 rpc_alloc_inode(struct super_block *sb)
 198 {
 199         struct rpc_inode *rpci;
 200         rpci = alloc_inode_sb(sb, rpc_inode_cachep, GFP_KERNEL);
 201         if (!rpci)
 202                 return NULL;
 203         return &rpci->vfs_inode;
 204 }
 205
 206 static void
 207 rpc_free_inode(struct inode *inode)
 208 {
 209         kmem_cache_free(rpc_inode_cachep, RPC_I(inode));
 210 }
 211
 212 static int
 213 rpc_pipe_open(struct inode *inode, struct file *filp)
 214 {
 215         struct rpc_pipe *pipe;
 216         int first_open;
 217         int res = -ENXIO;
 218
 219         inode_lock(inode);
 220         pipe = RPC_I(inode)->pipe;
 221         if (pipe == NULL)
 222                 goto out;
 223         first_open = pipe->nreaders == 0 && pipe->nwriters == 0;
 224         if (first_open && pipe->ops->open_pipe) {
 225                 res = pipe->ops->open_pipe(inode);
 226                 if (res)
 227                         goto out;
 228         }
 229         if (filp->f_mode & FMODE_READ)
 230                 pipe->nreaders++;
 231         if (filp->f_mode & FMODE_WRITE)
 232                 pipe->nwriters++;
 233         res = 0;
 234 out:
 235         inode_unlock(inode);
 236         return res;
 237 }
 238
 239 static int
 240 rpc_pipe_release(struct inode *inode, struct file *filp)
 241 {
 242         struct rpc_pipe *pipe;
 243         struct rpc_pipe_msg *msg;
 244         int last_close;
 245
 246         inode_lock(inode);
 247         pipe = RPC_I(inode)->pipe;
 248         if (pipe == NULL)
 249                 goto out;
 250         msg = filp->private_data;
 251         if (msg != NULL) {
 252                 spin_lock(&pipe->lock);
 253                 msg->errno = -EAGAIN;
 254                 list_del_init(&msg->list);
 255                 spin_unlock(&pipe->lock);
 256                 pipe->ops->destroy_msg(msg);
 257         }
 258         if (filp->f_mode & FMODE_WRITE)
 259                 pipe->nwriters --;
 260         if (filp->f_mode & FMODE_READ) {
 261                 pipe->nreaders --;
 262                 if (pipe->nreaders == 0) {
 263                         LIST_HEAD(free_list);
 264                         spin_lock(&pipe->lock);
 265                         list_splice_init(&pipe->pipe, &free_list);
 266                         pipe->pipelen = 0;
 267                         spin_unlock(&pipe->lock);
 268                         rpc_purge_list(&RPC_I(inode)->waitq, &free_list,
 269                                         pipe->ops->destroy_msg, -EAGAIN);
 270                 }
 271         }
 272         last_close = pipe->nwriters == 0 && pipe->nreaders == 0;
 273         if (last_close && pipe->ops->release_pipe)
 274                 pipe->ops->release_pipe(inode);
 275 out:
 276         inode_unlock(inode);
 277         return 0;
 278 }
 279
 280 static ssize_t
 281 rpc_pipe_read(struct file *filp, char __user *buf, size_t len, loff_t *offset)
 282 {
 283         struct inode *inode = file_inode(filp);
 284         struct rpc_pipe *pipe;
 285         struct rpc_pipe_msg *msg;
 286         int res = 0;
 287
 288         inode_lock(inode);
 289         pipe = RPC_I(inode)->pipe;
 290         if (pipe == NULL) {
 291                 res = -EPIPE;
 292                 goto out_unlock;
 293         }
 294         msg = filp->private_data;
 295         if (msg == NULL) {
 296                 spin_lock(&pipe->lock);
 297                 if (!list_empty(&pipe->pipe)) {
 298                         msg = list_entry(pipe->pipe.next,
 299                                         struct rpc_pipe_msg,
 300                                         list);
 301                         list_move(&msg->list, &pipe->in_upcall);
 302                         pipe->pipelen -= msg->len;
 303                         filp->private_data = msg;
 304                         msg->copied = 0;
 305                 }
 306                 spin_unlock(&pipe->lock);
 307                 if (msg == NULL)
 308                         goto out_unlock;
 309         }
 310         /* NOTE: it is up to the callback to update msg->copied */
 311         res = pipe->ops->upcall(filp, msg, buf, len);
 312         if (res < 0 || msg->len == msg->copied) {
 313                 filp->private_data = NULL;
 314                 spin_lock(&pipe->lock);
 315                 list_del_init(&msg->list);
 316                 spin_unlock(&pipe->lock);
 317                 pipe->ops->destroy_msg(msg);
 318         }
 319 out_unlock:
 320         inode_unlock(inode);
 321         return res;
 322 }
 323
 324 static ssize_t
 325 rpc_pipe_write(struct file *filp, const char __user *buf, size_t len, loff_t *offset)
 326 {
 327         struct inode *inode = file_inode(filp);
 328         int res;
 329
 330         inode_lock(inode);
 331         res = -EPIPE;
 332         if (RPC_I(inode)->pipe != NULL)
 333                 res = RPC_I(inode)->pipe->ops->downcall(filp, buf, len);
 334         inode_unlock(inode);
 335         return res;
 336 }
 337
 338 static __poll_t
 339 rpc_pipe_poll(struct file *filp, struct poll_table_struct *wait)
 340 {
 341         struct inode *inode = file_inode(filp);
 342         struct rpc_inode *rpci = RPC_I(inode);
 343         __poll_t mask = EPOLLOUT | EPOLLWRNORM;
 344
 345         poll_wait(filp, &rpci->waitq, wait);
 346
 347         inode_lock(inode);
 348         if (rpci->pipe == NULL)
 349                 mask |= EPOLLERR | EPOLLHUP;
 350         else if (filp->private_data || !list_empty(&rpci->pipe->pipe))
 351                 mask |= EPOLLIN | EPOLLRDNORM;
 352         inode_unlock(inode);
 353         return mask;
 354 }
 355
 356 static long
 357 rpc_pipe_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 358 {
 359         struct inode *inode = file_inode(filp);
 360         struct rpc_pipe *pipe;
 361         int len;
 362
 363         switch (cmd) {
 364         case FIONREAD:
 365                 inode_lock(inode);
 366                 pipe = RPC_I(inode)->pipe;
 367                 if (pipe == NULL) {
 368                         inode_unlock(inode);
 369                         return -EPIPE;
 370                 }
 371                 spin_lock(&pipe->lock);
 372                 len = pipe->pipelen;
 373                 if (filp->private_data) {
 374                         struct rpc_pipe_msg *msg;
 375                         msg = filp->private_data;
 376                         len += msg->len - msg->copied;
 377                 }
 378                 spin_unlock(&pipe->lock);
 379                 inode_unlock(inode);
 380                 return put_user(len, (int __user *)arg);
 381         default:
 382                 return -EINVAL;
 383         }
 384 }
 385
 386 static const struct file_operations rpc_pipe_fops = {
 387         .owner          = THIS_MODULE,
 388         .llseek         = no_llseek,
 389         .read           = rpc_pipe_read,
 390         .write          = rpc_pipe_write,
 391         .poll           = rpc_pipe_poll,
 392         .unlocked_ioctl = rpc_pipe_ioctl,
 393         .open           = rpc_pipe_open,
 394         .release        = rpc_pipe_release,
 395 };
 396
 397 static int
 398 rpc_show_info(struct seq_file *m, void *v)
 399 {
 400         struct rpc_clnt *clnt = m->private;
 401
 402         rcu_read_lock();
 403         seq_printf(m, "RPC server: %s\n",
 404                         rcu_dereference(clnt->cl_xprt)->servername);
 405         seq_printf(m, "service: %s (%d) version %d\n", clnt->cl_program->name,
 406                         clnt->cl_prog, clnt->cl_vers);
 407         seq_printf(m, "address: %s\n", rpc_peeraddr2str(clnt, RPC_DISPLAY_ADDR));
 408         seq_printf(m, "protocol: %s\n", rpc_peeraddr2str(clnt, RPC_DISPLAY_PROTO));
 409         seq_printf(m, "port: %s\n", rpc_peeraddr2str(clnt, RPC_DISPLAY_PORT));
 410         rcu_read_unlock();
 411         return 0;
 412 }
 413
 414 static int
 415 rpc_info_open(struct inode *inode, struct file *file)
 416 {
 417         struct rpc_clnt *clnt = NULL;
 418         int ret = single_open(file, rpc_show_info, NULL);
 419
 420         if (!ret) {
 421                 struct seq_file *m = file->private_data;
 422
 423                 spin_lock(&file->f_path.dentry->d_lock);
 424                 if (!d_unhashed(file->f_path.dentry))
 425                         clnt = RPC_I(inode)->private;
 426                 if (clnt != NULL && refcount_inc_not_zero(&clnt->cl_count)) {
 427                         spin_unlock(&file->f_path.dentry->d_lock);
 428                         m->private = clnt;
 429                 } else {
 430                         spin_unlock(&file->f_path.dentry->d_lock);
 431                         single_release(inode, file);
 432                         ret = -EINVAL;
 433                 }
 434         }
 435         return ret;
 436 }
 437
 438 static int
 439 rpc_info_release(struct inode *inode, struct file *file)
 440 {
 441         struct seq_file *m = file->private_data;
 442         struct rpc_clnt *clnt = (struct rpc_clnt *)m->private;
 443
 444         if (clnt)
 445                 rpc_release_client(clnt);
 446         return single_release(inode, file);
 447 }
 448
 449 static const struct file_operations rpc_info_operations = {
 450         .owner          = THIS_MODULE,
 451         .open           = rpc_info_open,
 452         .read           = seq_read,
 453         .llseek         = seq_lseek,
 454         .release        = rpc_info_release,
 455 };
 456
 457
 458 /*
 459  * Description of fs contents.
 460  */
 461 struct rpc_filelist {
 462         const char *name;
 463         const struct file_operations *i_fop;
 464         umode_t mode;
 465 };
 466
 467 static struct inode *
 468 rpc_get_inode(struct super_block *sb, umode_t mode)
 469 {
 470         struct inode *inode = new_inode(sb);
 471         if (!inode)
 472                 return NULL;
 473         inode->i_ino = get_next_ino();
 474         inode->i_mode = mode;
 475         inode->i_atime = inode->i_mtime = inode_set_ctime_current(inode);
 476         switch (mode & S_IFMT) {
 477         case S_IFDIR:
 478                 inode->i_fop = &simple_dir_operations;
 479                 inode->i_op = &simple_dir_inode_operations;
 480                 inc_nlink(inode);
 481                 break;
 482         default:
 483                 break;
 484         }
 485         return inode;
 486 }
 487
 488 static int __rpc_create_common(struct inode *dir, struct dentry *dentry,
 489                                umode_t mode,
 490                                const struct file_operations *i_fop,
 491                                void *private)
 492 {
 493         struct inode *inode;
 494
 495         d_drop(dentry);
 496         inode = rpc_get_inode(dir->i_sb, mode);
 497         if (!inode)
 498                 goto out_err;
 499         inode->i_ino = iunique(dir->i_sb, 100);
 500         if (i_fop)
 501                 inode->i_fop = i_fop;
 502         if (private)
 503                 rpc_inode_setowner(inode, private);
 504         d_add(dentry, inode);
 505         return 0;
 506 out_err:
 507         printk(KERN_WARNING "%s: %s failed to allocate inode for dentry %pd\n",
 508                         __FILE__, __func__, dentry);
 509         dput(dentry);
 510         return -ENOMEM;
 511 }
 512
 513 static int __rpc_create(struct inode *dir, struct dentry *dentry,
 514                         umode_t mode,
 515                         const struct file_operations *i_fop,
 516                         void *private)
 517 {
 518         int err;
 519
 520         err = __rpc_create_common(dir, dentry, S_IFREG | mode, i_fop, private);
 521         if (err)
 522                 return err;
 523         fsnotify_create(dir, dentry);
 524         return 0;
 525 }
 526
 527 static int __rpc_mkdir(struct inode *dir, struct dentry *dentry,
 528                        umode_t mode,
 529                        const struct file_operations *i_fop,
 530                        void *private)
 531 {
 532         int err;
 533
 534         err = __rpc_create_common(dir, dentry, S_IFDIR | mode, i_fop, private);
 535         if (err)
 536                 return err;
 537         inc_nlink(dir);
 538         fsnotify_mkdir(dir, dentry);
 539         return 0;
 540 }
 541
 542 static void
 543 init_pipe(struct rpc_pipe *pipe)
 544 {
 545         pipe->nreaders = 0;
 546         pipe->nwriters = 0;
 547         INIT_LIST_HEAD(&pipe->in_upcall);
 548         INIT_LIST_HEAD(&pipe->in_downcall);
 549         INIT_LIST_HEAD(&pipe->pipe);
 550         pipe->pipelen = 0;
 551         INIT_DELAYED_WORK(&pipe->queue_timeout,
 552                             rpc_timeout_upcall_queue);
 553         pipe->ops = NULL;
 554         spin_lock_init(&pipe->lock);
 555         pipe->dentry = NULL;
 556 }
 557
 558 void rpc_destroy_pipe_data(struct rpc_pipe *pipe)
 559 {
 560         kfree(pipe);
 561 }
 562 EXPORT_SYMBOL_GPL(rpc_destroy_pipe_data);
 563
 564 struct rpc_pipe *rpc_mkpipe_data(const struct rpc_pipe_ops *ops, int flags)
 565 {
 566         struct rpc_pipe *pipe;
 567
 568         pipe = kzalloc(sizeof(struct rpc_pipe), GFP_KERNEL);
 569         if (!pipe)
 570                 return ERR_PTR(-ENOMEM);
 571         init_pipe(pipe);
 572         pipe->ops = ops;
 573         pipe->flags = flags;
 574         return pipe;
 575 }
 576 EXPORT_SYMBOL_GPL(rpc_mkpipe_data);
 577
 578 static int __rpc_mkpipe_dentry(struct inode *dir, struct dentry *dentry,
 579                                umode_t mode,
 580                                const struct file_operations *i_fop,
 581                                void *private,
 582                                struct rpc_pipe *pipe)
 583 {
 584         struct rpc_inode *rpci;
 585         int err;
 586
 587         err = __rpc_create_common(dir, dentry, S_IFIFO | mode, i_fop, private);
 588         if (err)
 589                 return err;
 590         rpci = RPC_I(d_inode(dentry));
 591         rpci->private = private;
 592         rpci->pipe = pipe;
 593         fsnotify_create(dir, dentry);
 594         return 0;
 595 }
 596
 597 static int __rpc_rmdir(struct inode *dir, struct dentry *dentry)
 598 {
 599         int ret;
 600
 601         dget(dentry);
 602         ret = simple_rmdir(dir, dentry);
 603         d_drop(dentry);
 604         if (!ret)
 605                 fsnotify_rmdir(dir, dentry);
 606         dput(dentry);
 607         return ret;
 608 }
 609
 610 static int __rpc_unlink(struct inode *dir, struct dentry *dentry)
 611 {
 612         int ret;
 613
 614         dget(dentry);
 615         ret = simple_unlink(dir, dentry);
 616         d_drop(dentry);
 617         if (!ret)
 618                 fsnotify_unlink(dir, dentry);
 619         dput(dentry);
 620         return ret;
 621 }
 622
 623 static int __rpc_rmpipe(struct inode *dir, struct dentry *dentry)
 624 {
 625         struct inode *inode = d_inode(dentry);
 626
 627         rpc_close_pipes(inode);
 628         return __rpc_unlink(dir, dentry);
 629 }
 630
 631 static struct dentry *__rpc_lookup_create_exclusive(struct dentry *parent,
 632                                           const char *name)
 633 {
 634         struct qstr q = QSTR_INIT(name, strlen(name));
 635         struct dentry *dentry = d_hash_and_lookup(parent, &q);
 636         if (!dentry) {
 637                 dentry = d_alloc(parent, &q);
 638                 if (!dentry)
 639                         return ERR_PTR(-ENOMEM);
 640         }
 641         if (d_really_is_negative(dentry))
 642                 return dentry;
 643         dput(dentry);
 644         return ERR_PTR(-EEXIST);
 645 }
 646
 647 /*
 648  * FIXME: This probably has races.
 649  */
 650 static void __rpc_depopulate(struct dentry *parent,
 651                              const struct rpc_filelist *files,
 652                              int start, int eof)
 653 {
 654         struct inode *dir = d_inode(parent);
 655         struct dentry *dentry;
 656         struct qstr name;
 657         int i;
 658
 659         for (i = start; i < eof; i++) {
 660                 name.name = files[i].name;
 661                 name.len = strlen(files[i].name);
 662                 dentry = d_hash_and_lookup(parent, &name);
 663
 664                 if (dentry == NULL)
 665                         continue;
 666                 if (d_really_is_negative(dentry))
 667                         goto next;
 668                 switch (d_inode(dentry)->i_mode & S_IFMT) {
 669                         default:
 670                                 BUG();
 671                         case S_IFREG:
 672                                 __rpc_unlink(dir, dentry);
 673                                 break;
 674                         case S_IFDIR:
 675                                 __rpc_rmdir(dir, dentry);
 676                 }
 677 next:
 678                 dput(dentry);
 679         }
 680 }
 681
 682 static void rpc_depopulate(struct dentry *parent,
 683                            const struct rpc_filelist *files,
 684                            int start, int eof)
 685 {
 686         struct inode *dir = d_inode(parent);
 687
 688         inode_lock_nested(dir, I_MUTEX_CHILD);
 689         __rpc_depopulate(parent, files, start, eof);
 690         inode_unlock(dir);
 691 }
 692
 693 static int rpc_populate(struct dentry *parent,
 694                         const struct rpc_filelist *files,
 695                         int start, int eof,
 696                         void *private)
 697 {
 698         struct inode *dir = d_inode(parent);
 699         struct dentry *dentry;
 700         int i, err;
 701
 702         inode_lock(dir);
 703         for (i = start; i < eof; i++) {
 704                 dentry = __rpc_lookup_create_exclusive(parent, files[i].name);
 705                 err = PTR_ERR(dentry);
 706                 if (IS_ERR(dentry))
 707                         goto out_bad;
 708                 switch (files[i].mode & S_IFMT) {
 709                         default:
 710                                 BUG();
 711                         case S_IFREG:
 712                                 err = __rpc_create(dir, dentry,
 713                                                 files[i].mode,
 714                                                 files[i].i_fop,
 715                                                 private);
 716                                 break;
 717                         case S_IFDIR:
 718                                 err = __rpc_mkdir(dir, dentry,
 719                                                 files[i].mode,
 720                                                 NULL,
 721                                                 private);
 722                 }
 723                 if (err != 0)
 724                         goto out_bad;
 725         }
 726         inode_unlock(dir);
 727         return 0;
 728 out_bad:
 729         __rpc_depopulate(parent, files, start, eof);
 730         inode_unlock(dir);
 731         printk(KERN_WARNING "%s: %s failed to populate directory %pd\n",
 732                         __FILE__, __func__, parent);
 733         return err;
 734 }
 735
 736 static struct dentry *rpc_mkdir_populate(struct dentry *parent,
 737                 const char *name, umode_t mode, void *private,
 738                 int (*populate)(struct dentry *, void *), void *args_populate)
 739 {
 740         struct dentry *dentry;
 741         struct inode *dir = d_inode(parent);
 742         int error;
 743
 744         inode_lock_nested(dir, I_MUTEX_PARENT);
 745         dentry = __rpc_lookup_create_exclusive(parent, name);
 746         if (IS_ERR(dentry))
 747                 goto out;
 748         error = __rpc_mkdir(dir, dentry, mode, NULL, private);
 749         if (error != 0)
 750                 goto out_err;
 751         if (populate != NULL) {
 752                 error = populate(dentry, args_populate);
 753                 if (error)
 754                         goto err_rmdir;
 755         }
 756 out:
 757         inode_unlock(dir);
 758         return dentry;
 759 err_rmdir:
 760         __rpc_rmdir(dir, dentry);
 761 out_err:
 762         dentry = ERR_PTR(error);
 763         goto out;
 764 }
 765
 766 static int rpc_rmdir_depopulate(struct dentry *dentry,
 767                 void (*depopulate)(struct dentry *))
 768 {
 769         struct dentry *parent;
 770         struct inode *dir;
 771         int error;
 772
 773         parent = dget_parent(dentry);
 774         dir = d_inode(parent);
 775         inode_lock_nested(dir, I_MUTEX_PARENT);
 776         if (depopulate != NULL)
 777                 depopulate(dentry);
 778         error = __rpc_rmdir(dir, dentry);
 779         inode_unlock(dir);
 780         dput(parent);
 781         return error;
 782 }
 783
 784 /**
 785  * rpc_mkpipe_dentry - make an rpc_pipefs file for kernel<->userspace
 786  *                     communication
 787  * @parent: dentry of directory to create new "pipe" in
 788  * @name: name of pipe
 789  * @private: private data to associate with the pipe, for the caller's use
 790  * @pipe: &rpc_pipe containing input parameters
 791  *
 792  * Data is made available for userspace to read by calls to
 793  * rpc_queue_upcall().  The actual reads will result in calls to
 794  * @ops->upcall, which will be called with the file pointer,
 795  * message, and userspace buffer to copy to.
 796  *
 797  * Writes can come at any time, and do not necessarily have to be
 798  * responses to upcalls.  They will result in calls to @msg->downcall.
 799  *
 800  * The @private argument passed here will be available to all these methods
 801  * from the file pointer, via RPC_I(file_inode(file))->private.
 802  */
 803 struct dentry *rpc_mkpipe_dentry(struct dentry *parent, const char *name,
 804                                  void *private, struct rpc_pipe *pipe)
 805 {
 806         struct dentry *dentry;
 807         struct inode *dir = d_inode(parent);
 808         umode_t umode = S_IFIFO | 0600;
 809         int err;
 810
 811         if (pipe->ops->upcall == NULL)
 812                 umode &= ~0444;
 813         if (pipe->ops->downcall == NULL)
 814                 umode &= ~0222;
 815
 816         inode_lock_nested(dir, I_MUTEX_PARENT);
 817         dentry = __rpc_lookup_create_exclusive(parent, name);
 818         if (IS_ERR(dentry))
 819                 goto out;
 820         err = __rpc_mkpipe_dentry(dir, dentry, umode, &rpc_pipe_fops,
 821                                   private, pipe);
 822         if (err)
 823                 goto out_err;
 824 out:
 825         inode_unlock(dir);
 826         return dentry;
 827 out_err:
 828         dentry = ERR_PTR(err);
 829         printk(KERN_WARNING "%s: %s() failed to create pipe %pd/%s (errno = %d)\n",
 830                         __FILE__, __func__, parent, name,
 831                         err);
 832         goto out;
 833 }
 834 EXPORT_SYMBOL_GPL(rpc_mkpipe_dentry);
 835
 836 /**
 837  * rpc_unlink - remove a pipe
 838  * @dentry: dentry for the pipe, as returned from rpc_mkpipe
 839  *
 840  * After this call, lookups will no longer find the pipe, and any
 841  * attempts to read or write using preexisting opens of the pipe will
 842  * return -EPIPE.
 843  */
 844 int
 845 rpc_unlink(struct dentry *dentry)
 846 {
 847         struct dentry *parent;
 848         struct inode *dir;
 849         int error = 0;
 850
 851         parent = dget_parent(dentry);
 852         dir = d_inode(parent);
 853         inode_lock_nested(dir, I_MUTEX_PARENT);
 854         error = __rpc_rmpipe(dir, dentry);
 855         inode_unlock(dir);
 856         dput(parent);
 857         return error;
 858 }
 859 EXPORT_SYMBOL_GPL(rpc_unlink);
 860
 861 /**
 862  * rpc_init_pipe_dir_head - initialise a struct rpc_pipe_dir_head
 863  * @pdh: pointer to struct rpc_pipe_dir_head
 864  */
 865 void rpc_init_pipe_dir_head(struct rpc_pipe_dir_head *pdh)
 866 {
 867         INIT_LIST_HEAD(&pdh->pdh_entries);
 868         pdh->pdh_dentry = NULL;
 869 }
 870 EXPORT_SYMBOL_GPL(rpc_init_pipe_dir_head);
 871
 872 /**
 873  * rpc_init_pipe_dir_object - initialise a struct rpc_pipe_dir_object
 874  * @pdo: pointer to struct rpc_pipe_dir_object
 875  * @pdo_ops: pointer to const struct rpc_pipe_dir_object_ops
 876  * @pdo_data: pointer to caller-defined data
 877  */
 878 void rpc_init_pipe_dir_object(struct rpc_pipe_dir_object *pdo,
 879                 const struct rpc_pipe_dir_object_ops *pdo_ops,
 880                 void *pdo_data)
 881 {
 882         INIT_LIST_HEAD(&pdo->pdo_head);
 883         pdo->pdo_ops = pdo_ops;
 884         pdo->pdo_data = pdo_data;
 885 }
 886 EXPORT_SYMBOL_GPL(rpc_init_pipe_dir_object);
 887
 888 static int
 889 rpc_add_pipe_dir_object_locked(struct net *net,
 890                 struct rpc_pipe_dir_head *pdh,
 891                 struct rpc_pipe_dir_object *pdo)
 892 {
 893         int ret = 0;
 894
 895         if (pdh->pdh_dentry)
 896                 ret = pdo->pdo_ops->create(pdh->pdh_dentry, pdo);
 897         if (ret == 0)
 898                 list_add_tail(&pdo->pdo_head, &pdh->pdh_entries);
 899         return ret;
 900 }
 901
 902 static void
 903 rpc_remove_pipe_dir_object_locked(struct net *net,
 904                 struct rpc_pipe_dir_head *pdh,
 905                 struct rpc_pipe_dir_object *pdo)
 906 {
 907         if (pdh->pdh_dentry)
 908                 pdo->pdo_ops->destroy(pdh->pdh_dentry, pdo);
 909         list_del_init(&pdo->pdo_head);
 910 }
 911
 912 /**
 913  * rpc_add_pipe_dir_object - associate a rpc_pipe_dir_object to a directory
 914  * @net: pointer to struct net
 915  * @pdh: pointer to struct rpc_pipe_dir_head
 916  * @pdo: pointer to struct rpc_pipe_dir_object
 917  *
 918  */
 919 int
 920 rpc_add_pipe_dir_object(struct net *net,
 921                 struct rpc_pipe_dir_head *pdh,
 922                 struct rpc_pipe_dir_object *pdo)
 923 {
 924         int ret = 0;
 925
 926         if (list_empty(&pdo->pdo_head)) {
 927                 struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
 928
 929                 mutex_lock(&sn->pipefs_sb_lock);
 930                 ret = rpc_add_pipe_dir_object_locked(net, pdh, pdo);
 931                 mutex_unlock(&sn->pipefs_sb_lock);
 932         }
 933         return ret;
 934 }
 935 EXPORT_SYMBOL_GPL(rpc_add_pipe_dir_object);
 936
 937 /**
 938  * rpc_remove_pipe_dir_object - remove a rpc_pipe_dir_object from a directory
 939  * @net: pointer to struct net
 940  * @pdh: pointer to struct rpc_pipe_dir_head
 941  * @pdo: pointer to struct rpc_pipe_dir_object
 942  *
 943  */
 944 void
 945 rpc_remove_pipe_dir_object(struct net *net,
 946                 struct rpc_pipe_dir_head *pdh,
 947                 struct rpc_pipe_dir_object *pdo)
 948 {
 949         if (!list_empty(&pdo->pdo_head)) {
 950                 struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
 951
 952                 mutex_lock(&sn->pipefs_sb_lock);
 953                 rpc_remove_pipe_dir_object_locked(net, pdh, pdo);
 954                 mutex_unlock(&sn->pipefs_sb_lock);
 955         }
 956 }
 957 EXPORT_SYMBOL_GPL(rpc_remove_pipe_dir_object);
 958
 959 /**
 960  * rpc_find_or_alloc_pipe_dir_object
 961  * @net: pointer to struct net
 962  * @pdh: pointer to struct rpc_pipe_dir_head
 963  * @match: match struct rpc_pipe_dir_object to data
 964  * @alloc: allocate a new struct rpc_pipe_dir_object
 965  * @data: user defined data for match() and alloc()
 966  *
 967  */
 968 struct rpc_pipe_dir_object *
 969 rpc_find_or_alloc_pipe_dir_object(struct net *net,
 970                 struct rpc_pipe_dir_head *pdh,
 971                 int (*match)(struct rpc_pipe_dir_object *, void *),
 972                 struct rpc_pipe_dir_object *(*alloc)(void *),
 973                 void *data)
 974 {
 975         struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
 976         struct rpc_pipe_dir_object *pdo;
 977
 978         mutex_lock(&sn->pipefs_sb_lock);
 979         list_for_each_entry(pdo, &pdh->pdh_entries, pdo_head) {
 980                 if (!match(pdo, data))
 981                         continue;
 982                 goto out;
 983         }
 984         pdo = alloc(data);
 985         if (!pdo)
 986                 goto out;
 987         rpc_add_pipe_dir_object_locked(net, pdh, pdo);
 988 out:
 989         mutex_unlock(&sn->pipefs_sb_lock);
 990         return pdo;
 991 }
 992 EXPORT_SYMBOL_GPL(rpc_find_or_alloc_pipe_dir_object);
 993
 994 static void
 995 rpc_create_pipe_dir_objects(struct rpc_pipe_dir_head *pdh)
 996 {
 997         struct rpc_pipe_dir_object *pdo;
 998         struct dentry *dir = pdh->pdh_dentry;
 999
1000         list_for_each_entry(pdo, &pdh->pdh_entries, pdo_head)
1001                 pdo->pdo_ops->create(dir, pdo);
1002 }
1003
1004 static void
1005 rpc_destroy_pipe_dir_objects(struct rpc_pipe_dir_head *pdh)
1006 {
1007         struct rpc_pipe_dir_object *pdo;
1008         struct dentry *dir = pdh->pdh_dentry;
1009
1010         list_for_each_entry(pdo, &pdh->pdh_entries, pdo_head)
1011                 pdo->pdo_ops->destroy(dir, pdo);
1012 }
1013
1014 enum {
1015         RPCAUTH_info,
1016         RPCAUTH_EOF
1017 };
1018
1019 static const struct rpc_filelist authfiles[] = {
1020         [RPCAUTH_info] = {
1021                 .name = "info",
1022                 .i_fop = &rpc_info_operations,
1023                 .mode = S_IFREG | 0400,
1024         },
1025 };
1026
1027 static int rpc_clntdir_populate(struct dentry *dentry, void *private)
1028 {
1029         return rpc_populate(dentry,
1030                             authfiles, RPCAUTH_info, RPCAUTH_EOF,
1031                             private);
1032 }
1033
1034 static void rpc_clntdir_depopulate(struct dentry *dentry)
1035 {
1036         rpc_depopulate(dentry, authfiles, RPCAUTH_info, RPCAUTH_EOF);
1037 }
1038
1039 /**
1040  * rpc_create_client_dir - Create a new rpc_client directory in rpc_pipefs
1041  * @dentry: the parent of new directory
1042  * @name: the name of new directory
1043  * @rpc_client: rpc client to associate with this directory
1044  *
1045  * This creates a directory at the given @path associated with
1046  * @rpc_clnt, which will contain a file named "info" with some basic
1047  * information about the client, together with any "pipes" that may
1048  * later be created using rpc_mkpipe().
1049  */
1050 struct dentry *rpc_create_client_dir(struct dentry *dentry,
1051                                    const char *name,
1052                                    struct rpc_clnt *rpc_client)
1053 {
1054         struct dentry *ret;
1055
1056         ret = rpc_mkdir_populate(dentry, name, 0555, NULL,
1057                                  rpc_clntdir_populate, rpc_client);
1058         if (!IS_ERR(ret)) {
1059                 rpc_client->cl_pipedir_objects.pdh_dentry = ret;
1060                 rpc_create_pipe_dir_objects(&rpc_client->cl_pipedir_objects);
1061         }
1062         return ret;
1063 }
1064
1065 /**
1066  * rpc_remove_client_dir - Remove a directory created with rpc_create_client_dir()
1067  * @rpc_client: rpc_client for the pipe
1068  */
1069 int rpc_remove_client_dir(struct rpc_clnt *rpc_client)
1070 {
1071         struct dentry *dentry = rpc_client->cl_pipedir_objects.pdh_dentry;
1072
1073         if (dentry == NULL)
1074                 return 0;
1075         rpc_destroy_pipe_dir_objects(&rpc_client->cl_pipedir_objects);
1076         rpc_client->cl_pipedir_objects.pdh_dentry = NULL;
1077         return rpc_rmdir_depopulate(dentry, rpc_clntdir_depopulate);
1078 }
1079
1080 static const struct rpc_filelist cache_pipefs_files[3] = {
1081         [0] = {
1082                 .name = "channel",
1083                 .i_fop = &cache_file_operations_pipefs,
1084                 .mode = S_IFREG | 0600,
1085         },
1086         [1] = {
1087                 .name = "content",
1088                 .i_fop = &content_file_operations_pipefs,
1089                 .mode = S_IFREG | 0400,
1090         },
1091         [2] = {
1092                 .name = "flush",
1093                 .i_fop = &cache_flush_operations_pipefs,
1094                 .mode = S_IFREG | 0600,
1095         },
1096 };
1097
1098 static int rpc_cachedir_populate(struct dentry *dentry, void *private)
1099 {
1100         return rpc_populate(dentry,
1101                             cache_pipefs_files, 0, 3,
1102                             private);
1103 }
1104
1105 static void rpc_cachedir_depopulate(struct dentry *dentry)
1106 {
1107         rpc_depopulate(dentry, cache_pipefs_files, 0, 3);
1108 }
1109
1110 struct dentry *rpc_create_cache_dir(struct dentry *parent, const char *name,
1111                                     umode_t umode, struct cache_detail *cd)
1112 {
1113         return rpc_mkdir_populate(parent, name, umode, NULL,
1114                         rpc_cachedir_populate, cd);
1115 }
1116
1117 void rpc_remove_cache_dir(struct dentry *dentry)
1118 {
1119         rpc_rmdir_depopulate(dentry, rpc_cachedir_depopulate);
1120 }
1121
1122 /*
1123  * populate the filesystem
1124  */
1125 static const struct super_operations s_ops = {
1126         .alloc_inode    = rpc_alloc_inode,
1127         .free_inode     = rpc_free_inode,
1128         .statfs         = simple_statfs,
1129 };
1130
1131 #define RPCAUTH_GSSMAGIC 0x67596969
1132
1133 /*
1134  * We have a single directory with 1 node in it.
1135  */
1136 enum {
1137         RPCAUTH_lockd,
1138         RPCAUTH_mount,
1139         RPCAUTH_nfs,
1140         RPCAUTH_portmap,
1141         RPCAUTH_statd,
1142         RPCAUTH_nfsd4_cb,
1143         RPCAUTH_cache,
1144         RPCAUTH_nfsd,
1145         RPCAUTH_gssd,
1146         RPCAUTH_RootEOF
1147 };
1148
1149 static const struct rpc_filelist files[] = {
1150         [RPCAUTH_lockd] = {
1151                 .name = "lockd",
1152                 .mode = S_IFDIR | 0555,
1153         },
1154         [RPCAUTH_mount] = {
1155                 .name = "mount",
1156                 .mode = S_IFDIR | 0555,
1157         },
1158         [RPCAUTH_nfs] = {
1159                 .name = "nfs",
1160                 .mode = S_IFDIR | 0555,
1161         },
1162         [RPCAUTH_portmap] = {
1163                 .name = "portmap",
1164                 .mode = S_IFDIR | 0555,
1165         },
1166         [RPCAUTH_statd] = {
1167                 .name = "statd",
1168                 .mode = S_IFDIR | 0555,
1169         },
1170         [RPCAUTH_nfsd4_cb] = {
1171                 .name = "nfsd4_cb",
1172                 .mode = S_IFDIR | 0555,
1173         },
1174         [RPCAUTH_cache] = {
1175                 .name = "cache",
1176                 .mode = S_IFDIR | 0555,
1177         },
1178         [RPCAUTH_nfsd] = {
1179                 .name = "nfsd",
1180                 .mode = S_IFDIR | 0555,
1181         },
1182         [RPCAUTH_gssd] = {
1183                 .name = "gssd",
1184                 .mode = S_IFDIR | 0555,
1185         },
1186 };
1187
1188 /*
1189  * This call can be used only in RPC pipefs mount notification hooks.
1190  */
1191 struct dentry *rpc_d_lookup_sb(const struct super_block *sb,
1192                                const unsigned char *dir_name)
1193 {
1194         struct qstr dir = QSTR_INIT(dir_name, strlen(dir_name));
1195         return d_hash_and_lookup(sb->s_root, &dir);
1196 }
1197 EXPORT_SYMBOL_GPL(rpc_d_lookup_sb);
1198
1199 int rpc_pipefs_init_net(struct net *net)
1200 {
1201         struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
1202
1203         sn->gssd_dummy = rpc_mkpipe_data(&gssd_dummy_pipe_ops, 0);
1204         if (IS_ERR(sn->gssd_dummy))
1205                 return PTR_ERR(sn->gssd_dummy);
1206
1207         mutex_init(&sn->pipefs_sb_lock);
1208         sn->pipe_version = -1;
1209         return 0;
1210 }
1211
1212 void rpc_pipefs_exit_net(struct net *net)
1213 {
1214         struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
1215
1216         rpc_destroy_pipe_data(sn->gssd_dummy);
1217 }
1218
1219 /*
1220  * This call will be used for per network namespace operations calls.
1221  * Note: Function will be returned with pipefs_sb_lock taken if superblock was
1222  * found. This lock have to be released by rpc_put_sb_net() when all operations
1223  * will be completed.
1224  */
1225 struct super_block *rpc_get_sb_net(const struct net *net)
1226 {
1227         struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
1228
1229         mutex_lock(&sn->pipefs_sb_lock);
1230         if (sn->pipefs_sb)
1231                 return sn->pipefs_sb;
1232         mutex_unlock(&sn->pipefs_sb_lock);
1233         return NULL;
1234 }
1235 EXPORT_SYMBOL_GPL(rpc_get_sb_net);
1236
1237 void rpc_put_sb_net(const struct net *net)
1238 {
1239         struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
1240
1241         WARN_ON(sn->pipefs_sb == NULL);
1242         mutex_unlock(&sn->pipefs_sb_lock);
1243 }
1244 EXPORT_SYMBOL_GPL(rpc_put_sb_net);
1245
1246 static const struct rpc_filelist gssd_dummy_clnt_dir[] = {
1247         [0] = {
1248                 .name = "clntXX",
1249                 .mode = S_IFDIR | 0555,
1250         },
1251 };
1252
1253 static ssize_t
1254 dummy_downcall(struct file *filp, const char __user *src, size_t len)
1255 {
1256         return -EINVAL;
1257 }
1258
1259 static const struct rpc_pipe_ops gssd_dummy_pipe_ops = {
1260         .upcall         = rpc_pipe_generic_upcall,
1261         .downcall       = dummy_downcall,
1262 };
1263
1264 /*
1265  * Here we present a bogus "info" file to keep rpc.gssd happy. We don't expect
1266  * that it will ever use this info to handle an upcall, but rpc.gssd expects
1267  * that this file will be there and have a certain format.
1268  */
1269 static int
1270 rpc_dummy_info_show(struct seq_file *m, void *v)
1271 {
1272         seq_printf(m, "RPC server: %s\n", utsname()->nodename);
1273         seq_printf(m, "service: foo (1) version 0\n");
1274         seq_printf(m, "address: 127.0.0.1\n");
1275         seq_printf(m, "protocol: tcp\n");
1276         seq_printf(m, "port: 0\n");
1277         return 0;
1278 }
1279 DEFINE_SHOW_ATTRIBUTE(rpc_dummy_info);
1280
1281 static const struct rpc_filelist gssd_dummy_info_file[] = {
1282         [0] = {
1283                 .name = "info",
1284                 .i_fop = &rpc_dummy_info_fops,
1285                 .mode = S_IFREG | 0400,
1286         },
1287 };
1288
1289 /**
1290  * rpc_gssd_dummy_populate - create a dummy gssd pipe
1291  * @root:       root of the rpc_pipefs filesystem
1292  * @pipe_data:  pipe data created when netns is initialized
1293  *
1294  * Create a dummy set of directories and a pipe that gssd can hold open to
1295  * indicate that it is up and running.
1296  */
1297 static struct dentry *
1298 rpc_gssd_dummy_populate(struct dentry *root, struct rpc_pipe *pipe_data)
1299 {
1300         int ret = 0;
1301         struct dentry *gssd_dentry;
1302         struct dentry *clnt_dentry = NULL;
1303         struct dentry *pipe_dentry = NULL;
1304         struct qstr q = QSTR_INIT(files[RPCAUTH_gssd].name,
1305                                   strlen(files[RPCAUTH_gssd].name));
1306
1307         /* We should never get this far if "gssd" doesn't exist */
1308         gssd_dentry = d_hash_and_lookup(root, &q);
1309         if (!gssd_dentry)
1310                 return ERR_PTR(-ENOENT);
1311
1312         ret = rpc_populate(gssd_dentry, gssd_dummy_clnt_dir, 0, 1, NULL);
1313         if (ret) {
1314                 pipe_dentry = ERR_PTR(ret);
1315                 goto out;
1316         }
1317
1318         q.name = gssd_dummy_clnt_dir[0].name;
1319         q.len = strlen(gssd_dummy_clnt_dir[0].name);
1320         clnt_dentry = d_hash_and_lookup(gssd_dentry, &q);
1321         if (!clnt_dentry) {
1322                 __rpc_depopulate(gssd_dentry, gssd_dummy_clnt_dir, 0, 1);
1323                 pipe_dentry = ERR_PTR(-ENOENT);
1324                 goto out;
1325         }
1326
1327         ret = rpc_populate(clnt_dentry, gssd_dummy_info_file, 0, 1, NULL);
1328         if (ret) {
1329                 __rpc_depopulate(gssd_dentry, gssd_dummy_clnt_dir, 0, 1);
1330                 pipe_dentry = ERR_PTR(ret);
1331                 goto out;
1332         }
1333
1334         pipe_dentry = rpc_mkpipe_dentry(clnt_dentry, "gssd", NULL, pipe_data);
1335         if (IS_ERR(pipe_dentry)) {
1336                 __rpc_depopulate(clnt_dentry, gssd_dummy_info_file, 0, 1);
1337                 __rpc_depopulate(gssd_dentry, gssd_dummy_clnt_dir, 0, 1);
1338         }
1339 out:
1340         dput(clnt_dentry);
1341         dput(gssd_dentry);
1342         return pipe_dentry;
1343 }
1344
1345 static void
1346 rpc_gssd_dummy_depopulate(struct dentry *pipe_dentry)
1347 {
1348         struct dentry *clnt_dir = pipe_dentry->d_parent;
1349         struct dentry *gssd_dir = clnt_dir->d_parent;
1350
1351         dget(pipe_dentry);
1352         __rpc_rmpipe(d_inode(clnt_dir), pipe_dentry);
1353         __rpc_depopulate(clnt_dir, gssd_dummy_info_file, 0, 1);
1354         __rpc_depopulate(gssd_dir, gssd_dummy_clnt_dir, 0, 1);
1355         dput(pipe_dentry);
1356 }
1357
1358 static int
1359 rpc_fill_super(struct super_block *sb, struct fs_context *fc)
1360 {
1361         struct inode *inode;
1362         struct dentry *root, *gssd_dentry;
1363         struct net *net = sb->s_fs_info;
1364         struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
1365         int err;
1366
1367         sb->s_blocksize = PAGE_SIZE;
1368         sb->s_blocksize_bits = PAGE_SHIFT;
1369         sb->s_magic = RPCAUTH_GSSMAGIC;
1370         sb->s_op = &s_ops;
1371         sb->s_d_op = &simple_dentry_operations;
1372         sb->s_time_gran = 1;
1373
1374         inode = rpc_get_inode(sb, S_IFDIR | 0555);
1375         sb->s_root = root = d_make_root(inode);
1376         if (!root)
1377                 return -ENOMEM;
1378         if (rpc_populate(root, files, RPCAUTH_lockd, RPCAUTH_RootEOF, NULL))
1379                 return -ENOMEM;
1380
1381         gssd_dentry = rpc_gssd_dummy_populate(root, sn->gssd_dummy);
1382         if (IS_ERR(gssd_dentry)) {
1383                 __rpc_depopulate(root, files, RPCAUTH_lockd, RPCAUTH_RootEOF);
1384                 return PTR_ERR(gssd_dentry);
1385         }
1386
1387         dprintk("RPC:       sending pipefs MOUNT notification for net %x%s\n",
1388                 net->ns.inum, NET_NAME(net));
1389         mutex_lock(&sn->pipefs_sb_lock);
1390         sn->pipefs_sb = sb;
1391         err = blocking_notifier_call_chain(&rpc_pipefs_notifier_list,
1392                                            RPC_PIPEFS_MOUNT,
1393                                            sb);
1394         if (err)
1395                 goto err_depopulate;
1396         mutex_unlock(&sn->pipefs_sb_lock);
1397         return 0;
1398
1399 err_depopulate:
1400         rpc_gssd_dummy_depopulate(gssd_dentry);
1401         blocking_notifier_call_chain(&rpc_pipefs_notifier_list,
1402                                            RPC_PIPEFS_UMOUNT,
1403                                            sb);
1404         sn->pipefs_sb = NULL;
1405         __rpc_depopulate(root, files, RPCAUTH_lockd, RPCAUTH_RootEOF);
1406         mutex_unlock(&sn->pipefs_sb_lock);
1407         return err;
1408 }
1409
1410 bool
1411 gssd_running(struct net *net)
1412 {
1413         struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
1414         struct rpc_pipe *pipe = sn->gssd_dummy;
1415
1416         return pipe->nreaders || pipe->nwriters;
1417 }
1418 EXPORT_SYMBOL_GPL(gssd_running);
1419
1420 static int rpc_fs_get_tree(struct fs_context *fc)
1421 {
1422         return get_tree_keyed(fc, rpc_fill_super, get_net(fc->net_ns));
1423 }
1424
1425 static void rpc_fs_free_fc(struct fs_context *fc)
1426 {
1427         if (fc->s_fs_info)
1428                 put_net(fc->s_fs_info);
1429 }
1430
1431 static const struct fs_context_operations rpc_fs_context_ops = {
1432         .free           = rpc_fs_free_fc,
1433         .get_tree       = rpc_fs_get_tree,
1434 };
1435
1436 static int rpc_init_fs_context(struct fs_context *fc)
1437 {
1438         put_user_ns(fc->user_ns);
1439         fc->user_ns = get_user_ns(fc->net_ns->user_ns);
1440         fc->ops = &rpc_fs_context_ops;
1441         return 0;
1442 }
1443
1444 static void rpc_kill_sb(struct super_block *sb)
1445 {
1446         struct net *net = sb->s_fs_info;
1447         struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
1448
1449         mutex_lock(&sn->pipefs_sb_lock);
1450         if (sn->pipefs_sb != sb) {
1451                 mutex_unlock(&sn->pipefs_sb_lock);
1452                 goto out;
1453         }
1454         sn->pipefs_sb = NULL;
1455         dprintk("RPC:       sending pipefs UMOUNT notification for net %x%s\n",
1456                 net->ns.inum, NET_NAME(net));
1457         blocking_notifier_call_chain(&rpc_pipefs_notifier_list,
1458                                            RPC_PIPEFS_UMOUNT,
1459                                            sb);
1460         mutex_unlock(&sn->pipefs_sb_lock);
1461 out:
1462         kill_litter_super(sb);
1463         put_net(net);
1464 }
1465
1466 static struct file_system_type rpc_pipe_fs_type = {
1467         .owner          = THIS_MODULE,
1468         .name           = "rpc_pipefs",
1469         .init_fs_context = rpc_init_fs_context,
1470         .kill_sb        = rpc_kill_sb,
1471 };
1472 MODULE_ALIAS_FS("rpc_pipefs");
1473 MODULE_ALIAS("rpc_pipefs");
1474
1475 static void
1476 init_once(void *foo)
1477 {
1478         struct rpc_inode *rpci = (struct rpc_inode *) foo;
1479
1480         inode_init_once(&rpci->vfs_inode);
1481         rpci->private = NULL;
1482         rpci->pipe = NULL;
1483         init_waitqueue_head(&rpci->waitq);
1484 }
1485
1486 int register_rpc_pipefs(void)
1487 {
1488         int err;
1489
1490         rpc_inode_cachep = kmem_cache_create("rpc_inode_cache",
1491                                 sizeof(struct rpc_inode),
1492                                 0, (SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT|
1493                                                 SLAB_MEM_SPREAD|SLAB_ACCOUNT),
1494                                 init_once);
1495         if (!rpc_inode_cachep)
1496                 return -ENOMEM;
1497         err = rpc_clients_notifier_register();
1498         if (err)
1499                 goto err_notifier;
1500         err = register_filesystem(&rpc_pipe_fs_type);
1501         if (err)
1502                 goto err_register;
1503         return 0;
1504
1505 err_register:
1506         rpc_clients_notifier_unregister();
1507 err_notifier:
1508         kmem_cache_destroy(rpc_inode_cachep);
1509         return err;
1510 }
1511
1512 void unregister_rpc_pipefs(void)
1513 {
1514         rpc_clients_notifier_unregister();
1515         unregister_filesystem(&rpc_pipe_fs_type);
1516         kmem_cache_destroy(rpc_inode_cachep);
1517 }