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 <[email protected]>
  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 = kmem_cache_alloc(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 && atomic_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->i_ctime = current_time(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         default:
 482                 break;
 483         }
 484         return inode;
 485 }
 486
 487 static int __rpc_create_common(struct inode *dir, struct dentry *dentry,
 488                                umode_t mode,
 489                                const struct file_operations *i_fop,
 490                                void *private)
 491 {
 492         struct inode *inode;
 493
 494         d_drop(dentry);
 495         inode = rpc_get_inode(dir->i_sb, mode);
 496         if (!inode)
 497                 goto out_err;
 498         inode->i_ino = iunique(dir->i_sb, 100);
 499         if (i_fop)
 500                 inode->i_fop = i_fop;
 501         if (private)
 502                 rpc_inode_setowner(inode, private);
 503         d_add(dentry, inode);
 504         return 0;
 505 out_err:
 506         printk(KERN_WARNING "%s: %s failed to allocate inode for dentry %pd\n",
 507                         __FILE__, __func__, dentry);
 508         dput(dentry);
 509         return -ENOMEM;
 510 }
 511
 512 static int __rpc_create(struct inode *dir, struct dentry *dentry,
 513                         umode_t mode,
 514                         const struct file_operations *i_fop,
 515                         void *private)
 516 {
 517         int err;
 518
 519         err = __rpc_create_common(dir, dentry, S_IFREG | mode, i_fop, private);
 520         if (err)
 521                 return err;
 522         fsnotify_create(dir, dentry);
 523         return 0;
 524 }
 525
 526 static int __rpc_mkdir(struct inode *dir, struct dentry *dentry,
 527                        umode_t mode,
 528                        const struct file_operations *i_fop,
 529                        void *private)
 530 {
 531         int err;
 532
 533         err = __rpc_create_common(dir, dentry, S_IFDIR | mode, i_fop, private);
 534         if (err)
 535                 return err;
 536         inc_nlink(dir);
 537         fsnotify_mkdir(dir, dentry);
 538         return 0;
 539 }
 540
 541 static void
 542 init_pipe(struct rpc_pipe *pipe)
 543 {
 544         pipe->nreaders = 0;
 545         pipe->nwriters = 0;
 546         INIT_LIST_HEAD(&pipe->in_upcall);
 547         INIT_LIST_HEAD(&pipe->in_downcall);
 548         INIT_LIST_HEAD(&pipe->pipe);
 549         pipe->pipelen = 0;
 550         INIT_DELAYED_WORK(&pipe->queue_timeout,
 551                             rpc_timeout_upcall_queue);
 552         pipe->ops = NULL;
 553         spin_lock_init(&pipe->lock);
 554         pipe->dentry = NULL;
 555 }
 556
 557 void rpc_destroy_pipe_data(struct rpc_pipe *pipe)
 558 {
 559         kfree(pipe);
 560 }
 561 EXPORT_SYMBOL_GPL(rpc_destroy_pipe_data);
 562
 563 struct rpc_pipe *rpc_mkpipe_data(const struct rpc_pipe_ops *ops, int flags)
 564 {
 565         struct rpc_pipe *pipe;
 566
 567         pipe = kzalloc(sizeof(struct rpc_pipe), GFP_KERNEL);
 568         if (!pipe)
 569                 return ERR_PTR(-ENOMEM);
 570         init_pipe(pipe);
 571         pipe->ops = ops;
 572         pipe->flags = flags;
 573         return pipe;
 574 }
 575 EXPORT_SYMBOL_GPL(rpc_mkpipe_data);
 576
 577 static int __rpc_mkpipe_dentry(struct inode *dir, struct dentry *dentry,
 578                                umode_t mode,
 579                                const struct file_operations *i_fop,
 580                                void *private,
 581                                struct rpc_pipe *pipe)
 582 {
 583         struct rpc_inode *rpci;
 584         int err;
 585
 586         err = __rpc_create_common(dir, dentry, S_IFIFO | mode, i_fop, private);
 587         if (err)
 588                 return err;
 589         rpci = RPC_I(d_inode(dentry));
 590         rpci->private = private;
 591         rpci->pipe = pipe;
 592         fsnotify_create(dir, dentry);
 593         return 0;
 594 }
 595
 596 static int __rpc_rmdir(struct inode *dir, struct dentry *dentry)
 597 {
 598         int ret;
 599
 600         dget(dentry);
 601         ret = simple_rmdir(dir, dentry);
 602         if (!ret)
 603                 fsnotify_rmdir(dir, dentry);
 604         d_delete(dentry);
 605         dput(dentry);
 606         return ret;
 607 }
 608
 609 static int __rpc_unlink(struct inode *dir, struct dentry *dentry)
 610 {
 611         int ret;
 612
 613         dget(dentry);
 614         ret = simple_unlink(dir, dentry);
 615         if (!ret)
 616                 fsnotify_unlink(dir, dentry);
 617         d_delete(dentry);
 618         dput(dentry);
 619         return ret;
 620 }
 621
 622 static int __rpc_rmpipe(struct inode *dir, struct dentry *dentry)
 623 {
 624         struct inode *inode = d_inode(dentry);
 625
 626         rpc_close_pipes(inode);
 627         return __rpc_unlink(dir, dentry);
 628 }
 629
 630 static struct dentry *__rpc_lookup_create_exclusive(struct dentry *parent,
 631                                           const char *name)
 632 {
 633         struct qstr q = QSTR_INIT(name, strlen(name));
 634         struct dentry *dentry = d_hash_and_lookup(parent, &q);
 635         if (!dentry) {
 636                 dentry = d_alloc(parent, &q);
 637                 if (!dentry)
 638                         return ERR_PTR(-ENOMEM);
 639         }
 640         if (d_really_is_negative(dentry))
 641                 return dentry;
 642         dput(dentry);
 643         return ERR_PTR(-EEXIST);
 644 }
 645
 646 /*
 647  * FIXME: This probably has races.
 648  */
 649 static void __rpc_depopulate(struct dentry *parent,
 650                              const struct rpc_filelist *files,
 651                              int start, int eof)
 652 {
 653         struct inode *dir = d_inode(parent);
 654         struct dentry *dentry;
 655         struct qstr name;
 656         int i;
 657
 658         for (i = start; i < eof; i++) {
 659                 name.name = files[i].name;
 660                 name.len = strlen(files[i].name);
 661                 dentry = d_hash_and_lookup(parent, &name);
 662
 663                 if (dentry == NULL)
 664                         continue;
 665                 if (d_really_is_negative(dentry))
 666                         goto next;
 667                 switch (d_inode(dentry)->i_mode & S_IFMT) {
 668                         default:
 669                                 BUG();
 670                         case S_IFREG:
 671                                 __rpc_unlink(dir, dentry);
 672                                 break;
 673                         case S_IFDIR:
 674                                 __rpc_rmdir(dir, dentry);
 675                 }
 676 next:
 677                 dput(dentry);
 678         }
 679 }
 680
 681 static void rpc_depopulate(struct dentry *parent,
 682                            const struct rpc_filelist *files,
 683                            int start, int eof)
 684 {
 685         struct inode *dir = d_inode(parent);
 686
 687         inode_lock_nested(dir, I_MUTEX_CHILD);
 688         __rpc_depopulate(parent, files, start, eof);
 689         inode_unlock(dir);
 690 }
 691
 692 static int rpc_populate(struct dentry *parent,
 693                         const struct rpc_filelist *files,
 694                         int start, int eof,
 695                         void *private)
 696 {
 697         struct inode *dir = d_inode(parent);
 698         struct dentry *dentry;
 699         int i, err;
 700
 701         inode_lock(dir);
 702         for (i = start; i < eof; i++) {
 703                 dentry = __rpc_lookup_create_exclusive(parent, files[i].name);
 704                 err = PTR_ERR(dentry);
 705                 if (IS_ERR(dentry))
 706                         goto out_bad;
 707                 switch (files[i].mode & S_IFMT) {
 708                         default:
 709                                 BUG();
 710                         case S_IFREG:
 711                                 err = __rpc_create(dir, dentry,
 712                                                 files[i].mode,
 713                                                 files[i].i_fop,
 714                                                 private);
 715                                 break;
 716                         case S_IFDIR:
 717                                 err = __rpc_mkdir(dir, dentry,
 718                                                 files[i].mode,
 719                                                 NULL,
 720                                                 private);
 721                 }
 722                 if (err != 0)
 723                         goto out_bad;
 724         }
 725         inode_unlock(dir);
 726         return 0;
 727 out_bad:
 728         __rpc_depopulate(parent, files, start, eof);
 729         inode_unlock(dir);
 730         printk(KERN_WARNING "%s: %s failed to populate directory %pd\n",
 731                         __FILE__, __func__, parent);
 732         return err;
 733 }
 734
 735 static struct dentry *rpc_mkdir_populate(struct dentry *parent,
 736                 const char *name, umode_t mode, void *private,
 737                 int (*populate)(struct dentry *, void *), void *args_populate)
 738 {
 739         struct dentry *dentry;
 740         struct inode *dir = d_inode(parent);
 741         int error;
 742
 743         inode_lock_nested(dir, I_MUTEX_PARENT);
 744         dentry = __rpc_lookup_create_exclusive(parent, name);
 745         if (IS_ERR(dentry))
 746                 goto out;
 747         error = __rpc_mkdir(dir, dentry, mode, NULL, private);
 748         if (error != 0)
 749                 goto out_err;
 750         if (populate != NULL) {
 751                 error = populate(dentry, args_populate);
 752                 if (error)
 753                         goto err_rmdir;
 754         }
 755 out:
 756         inode_unlock(dir);
 757         return dentry;
 758 err_rmdir:
 759         __rpc_rmdir(dir, dentry);
 760 out_err:
 761         dentry = ERR_PTR(error);
 762         goto out;
 763 }
 764
 765 static int rpc_rmdir_depopulate(struct dentry *dentry,
 766                 void (*depopulate)(struct dentry *))
 767 {
 768         struct dentry *parent;
 769         struct inode *dir;
 770         int error;
 771
 772         parent = dget_parent(dentry);
 773         dir = d_inode(parent);
 774         inode_lock_nested(dir, I_MUTEX_PARENT);
 775         if (depopulate != NULL)
 776                 depopulate(dentry);
 777         error = __rpc_rmdir(dir, dentry);
 778         inode_unlock(dir);
 779         dput(parent);
 780         return error;
 781 }
 782
 783 /**
 784  * rpc_mkpipe_dentry - make an rpc_pipefs file for kernel<->userspace
 785  *                     communication
 786  * @parent: dentry of directory to create new "pipe" in
 787  * @name: name of pipe
 788  * @private: private data to associate with the pipe, for the caller's use
 789  * @pipe: &rpc_pipe containing input parameters
 790  *
 791  * Data is made available for userspace to read by calls to
 792  * rpc_queue_upcall().  The actual reads will result in calls to
 793  * @ops->upcall, which will be called with the file pointer,
 794  * message, and userspace buffer to copy to.
 795  *
 796  * Writes can come at any time, and do not necessarily have to be
 797  * responses to upcalls.  They will result in calls to @msg->downcall.
 798  *
 799  * The @private argument passed here will be available to all these methods
 800  * from the file pointer, via RPC_I(file_inode(file))->private.
 801  */
 802 struct dentry *rpc_mkpipe_dentry(struct dentry *parent, const char *name,
 803                                  void *private, struct rpc_pipe *pipe)
 804 {
 805         struct dentry *dentry;
 806         struct inode *dir = d_inode(parent);
 807         umode_t umode = S_IFIFO | 0600;
 808         int err;
 809
 810         if (pipe->ops->upcall == NULL)
 811                 umode &= ~0444;
 812         if (pipe->ops->downcall == NULL)
 813                 umode &= ~0222;
 814
 815         inode_lock_nested(dir, I_MUTEX_PARENT);
 816         dentry = __rpc_lookup_create_exclusive(parent, name);
 817         if (IS_ERR(dentry))
 818                 goto out;
 819         err = __rpc_mkpipe_dentry(dir, dentry, umode, &rpc_pipe_fops,
 820                                   private, pipe);
 821         if (err)
 822                 goto out_err;
 823 out:
 824         inode_unlock(dir);
 825         return dentry;
 826 out_err:
 827         dentry = ERR_PTR(err);
 828         printk(KERN_WARNING "%s: %s() failed to create pipe %pd/%s (errno = %d)\n",
 829                         __FILE__, __func__, parent, name,
 830                         err);
 831         goto out;
 832 }
 833 EXPORT_SYMBOL_GPL(rpc_mkpipe_dentry);
 834
 835 /**
 836  * rpc_unlink - remove a pipe
 837  * @dentry: dentry for the pipe, as returned from rpc_mkpipe
 838  *
 839  * After this call, lookups will no longer find the pipe, and any
 840  * attempts to read or write using preexisting opens of the pipe will
 841  * return -EPIPE.
 842  */
 843 int
 844 rpc_unlink(struct dentry *dentry)
 845 {
 846         struct dentry *parent;
 847         struct inode *dir;
 848         int error = 0;
 849
 850         parent = dget_parent(dentry);
 851         dir = d_inode(parent);
 852         inode_lock_nested(dir, I_MUTEX_PARENT);
 853         error = __rpc_rmpipe(dir, dentry);
 854         inode_unlock(dir);
 855         dput(parent);
 856         return error;
 857 }
 858 EXPORT_SYMBOL_GPL(rpc_unlink);
 859
 860 /**
 861  * rpc_init_pipe_dir_head - initialise a struct rpc_pipe_dir_head
 862  * @pdh: pointer to struct rpc_pipe_dir_head
 863  */
 864 void rpc_init_pipe_dir_head(struct rpc_pipe_dir_head *pdh)
 865 {
 866         INIT_LIST_HEAD(&pdh->pdh_entries);
 867         pdh->pdh_dentry = NULL;
 868 }
 869 EXPORT_SYMBOL_GPL(rpc_init_pipe_dir_head);
 870
 871 /**
 872  * rpc_init_pipe_dir_object - initialise a struct rpc_pipe_dir_object
 873  * @pdo: pointer to struct rpc_pipe_dir_object
 874  * @pdo_ops: pointer to const struct rpc_pipe_dir_object_ops
 875  * @pdo_data: pointer to caller-defined data
 876  */
 877 void rpc_init_pipe_dir_object(struct rpc_pipe_dir_object *pdo,
 878                 const struct rpc_pipe_dir_object_ops *pdo_ops,
 879                 void *pdo_data)
 880 {
 881         INIT_LIST_HEAD(&pdo->pdo_head);
 882         pdo->pdo_ops = pdo_ops;
 883         pdo->pdo_data = pdo_data;
 884 }
 885 EXPORT_SYMBOL_GPL(rpc_init_pipe_dir_object);
 886
 887 static int
 888 rpc_add_pipe_dir_object_locked(struct net *net,
 889                 struct rpc_pipe_dir_head *pdh,
 890                 struct rpc_pipe_dir_object *pdo)
 891 {
 892         int ret = 0;
 893
 894         if (pdh->pdh_dentry)
 895                 ret = pdo->pdo_ops->create(pdh->pdh_dentry, pdo);
 896         if (ret == 0)
 897                 list_add_tail(&pdo->pdo_head, &pdh->pdh_entries);
 898         return ret;
 899 }
 900
 901 static void
 902 rpc_remove_pipe_dir_object_locked(struct net *net,
 903                 struct rpc_pipe_dir_head *pdh,
 904                 struct rpc_pipe_dir_object *pdo)
 905 {
 906         if (pdh->pdh_dentry)
 907                 pdo->pdo_ops->destroy(pdh->pdh_dentry, pdo);
 908         list_del_init(&pdo->pdo_head);
 909 }
 910
 911 /**
 912  * rpc_add_pipe_dir_object - associate a rpc_pipe_dir_object to a directory
 913  * @net: pointer to struct net
 914  * @pdh: pointer to struct rpc_pipe_dir_head
 915  * @pdo: pointer to struct rpc_pipe_dir_object
 916  *
 917  */
 918 int
 919 rpc_add_pipe_dir_object(struct net *net,
 920                 struct rpc_pipe_dir_head *pdh,
 921                 struct rpc_pipe_dir_object *pdo)
 922 {
 923         int ret = 0;
 924
 925         if (list_empty(&pdo->pdo_head)) {
 926                 struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
 927
 928                 mutex_lock(&sn->pipefs_sb_lock);
 929                 ret = rpc_add_pipe_dir_object_locked(net, pdh, pdo);
 930                 mutex_unlock(&sn->pipefs_sb_lock);
 931         }
 932         return ret;
 933 }
 934 EXPORT_SYMBOL_GPL(rpc_add_pipe_dir_object);
 935
 936 /**
 937  * rpc_remove_pipe_dir_object - remove a rpc_pipe_dir_object from a directory
 938  * @net: pointer to struct net
 939  * @pdh: pointer to struct rpc_pipe_dir_head
 940  * @pdo: pointer to struct rpc_pipe_dir_object
 941  *
 942  */
 943 void
 944 rpc_remove_pipe_dir_object(struct net *net,
 945                 struct rpc_pipe_dir_head *pdh,
 946                 struct rpc_pipe_dir_object *pdo)
 947 {
 948         if (!list_empty(&pdo->pdo_head)) {
 949                 struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
 950
 951                 mutex_lock(&sn->pipefs_sb_lock);
 952                 rpc_remove_pipe_dir_object_locked(net, pdh, pdo);
 953                 mutex_unlock(&sn->pipefs_sb_lock);
 954         }
 955 }
 956 EXPORT_SYMBOL_GPL(rpc_remove_pipe_dir_object);
 957
 958 /**
 959  * rpc_find_or_alloc_pipe_dir_object
 960  * @net: pointer to struct net
 961  * @pdh: pointer to struct rpc_pipe_dir_head
 962  * @match: match struct rpc_pipe_dir_object to data
 963  * @alloc: allocate a new struct rpc_pipe_dir_object
 964  * @data: user defined data for match() and alloc()
 965  *
 966  */
 967 struct rpc_pipe_dir_object *
 968 rpc_find_or_alloc_pipe_dir_object(struct net *net,
 969                 struct rpc_pipe_dir_head *pdh,
 970                 int (*match)(struct rpc_pipe_dir_object *, void *),
 971                 struct rpc_pipe_dir_object *(*alloc)(void *),
 972                 void *data)
 973 {
 974         struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
 975         struct rpc_pipe_dir_object *pdo;
 976
 977         mutex_lock(&sn->pipefs_sb_lock);
 978         list_for_each_entry(pdo, &pdh->pdh_entries, pdo_head) {
 979                 if (!match(pdo, data))
 980                         continue;
 981                 goto out;
 982         }
 983         pdo = alloc(data);
 984         if (!pdo)
 985                 goto out;
 986         rpc_add_pipe_dir_object_locked(net, pdh, pdo);
 987 out:
 988         mutex_unlock(&sn->pipefs_sb_lock);
 989         return pdo;
 990 }
 991 EXPORT_SYMBOL_GPL(rpc_find_or_alloc_pipe_dir_object);
 992
 993 static void
 994 rpc_create_pipe_dir_objects(struct rpc_pipe_dir_head *pdh)
 995 {
 996         struct rpc_pipe_dir_object *pdo;
 997         struct dentry *dir = pdh->pdh_dentry;
 998
 999         list_for_each_entry(pdo, &pdh->pdh_entries, pdo_head)
1000                 pdo->pdo_ops->create(dir, pdo);
1001 }
1002
1003 static void
1004 rpc_destroy_pipe_dir_objects(struct rpc_pipe_dir_head *pdh)
1005 {
1006         struct rpc_pipe_dir_object *pdo;
1007         struct dentry *dir = pdh->pdh_dentry;
1008
1009         list_for_each_entry(pdo, &pdh->pdh_entries, pdo_head)
1010                 pdo->pdo_ops->destroy(dir, pdo);
1011 }
1012
1013 enum {
1014         RPCAUTH_info,
1015         RPCAUTH_EOF
1016 };
1017
1018 static const struct rpc_filelist authfiles[] = {
1019         [RPCAUTH_info] = {
1020                 .name = "info",
1021                 .i_fop = &rpc_info_operations,
1022                 .mode = S_IFREG | 0400,
1023         },
1024 };
1025
1026 static int rpc_clntdir_populate(struct dentry *dentry, void *private)
1027 {
1028         return rpc_populate(dentry,
1029                             authfiles, RPCAUTH_info, RPCAUTH_EOF,
1030                             private);
1031 }
1032
1033 static void rpc_clntdir_depopulate(struct dentry *dentry)
1034 {
1035         rpc_depopulate(dentry, authfiles, RPCAUTH_info, RPCAUTH_EOF);
1036 }
1037
1038 /**
1039  * rpc_create_client_dir - Create a new rpc_client directory in rpc_pipefs
1040  * @dentry: the parent of new directory
1041  * @name: the name of new directory
1042  * @rpc_client: rpc client to associate with this directory
1043  *
1044  * This creates a directory at the given @path associated with
1045  * @rpc_clnt, which will contain a file named "info" with some basic
1046  * information about the client, together with any "pipes" that may
1047  * later be created using rpc_mkpipe().
1048  */
1049 struct dentry *rpc_create_client_dir(struct dentry *dentry,
1050                                    const char *name,
1051                                    struct rpc_clnt *rpc_client)
1052 {
1053         struct dentry *ret;
1054
1055         ret = rpc_mkdir_populate(dentry, name, 0555, NULL,
1056                                  rpc_clntdir_populate, rpc_client);
1057         if (!IS_ERR(ret)) {
1058                 rpc_client->cl_pipedir_objects.pdh_dentry = ret;
1059                 rpc_create_pipe_dir_objects(&rpc_client->cl_pipedir_objects);
1060         }
1061         return ret;
1062 }
1063
1064 /**
1065  * rpc_remove_client_dir - Remove a directory created with rpc_create_client_dir()
1066  * @rpc_client: rpc_client for the pipe
1067  */
1068 int rpc_remove_client_dir(struct rpc_clnt *rpc_client)
1069 {
1070         struct dentry *dentry = rpc_client->cl_pipedir_objects.pdh_dentry;
1071
1072         if (dentry == NULL)
1073                 return 0;
1074         rpc_destroy_pipe_dir_objects(&rpc_client->cl_pipedir_objects);
1075         rpc_client->cl_pipedir_objects.pdh_dentry = NULL;
1076         return rpc_rmdir_depopulate(dentry, rpc_clntdir_depopulate);
1077 }
1078
1079 static const struct rpc_filelist cache_pipefs_files[3] = {
1080         [0] = {
1081                 .name = "channel",
1082                 .i_fop = &cache_file_operations_pipefs,
1083                 .mode = S_IFREG | 0600,
1084         },
1085         [1] = {
1086                 .name = "content",
1087                 .i_fop = &content_file_operations_pipefs,
1088                 .mode = S_IFREG | 0400,
1089         },
1090         [2] = {
1091                 .name = "flush",
1092                 .i_fop = &cache_flush_operations_pipefs,
1093                 .mode = S_IFREG | 0600,
1094         },
1095 };
1096
1097 static int rpc_cachedir_populate(struct dentry *dentry, void *private)
1098 {
1099         return rpc_populate(dentry,
1100                             cache_pipefs_files, 0, 3,
1101                             private);
1102 }
1103
1104 static void rpc_cachedir_depopulate(struct dentry *dentry)
1105 {
1106         rpc_depopulate(dentry, cache_pipefs_files, 0, 3);
1107 }
1108
1109 struct dentry *rpc_create_cache_dir(struct dentry *parent, const char *name,
1110                                     umode_t umode, struct cache_detail *cd)
1111 {
1112         return rpc_mkdir_populate(parent, name, umode, NULL,
1113                         rpc_cachedir_populate, cd);
1114 }
1115
1116 void rpc_remove_cache_dir(struct dentry *dentry)
1117 {
1118         rpc_rmdir_depopulate(dentry, rpc_cachedir_depopulate);
1119 }
1120
1121 /*
1122  * populate the filesystem
1123  */
1124 static const struct super_operations s_ops = {
1125         .alloc_inode    = rpc_alloc_inode,
1126         .free_inode     = rpc_free_inode,
1127         .statfs         = simple_statfs,
1128 };
1129
1130 #define RPCAUTH_GSSMAGIC 0x67596969
1131
1132 /*
1133  * We have a single directory with 1 node in it.
1134  */
1135 enum {
1136         RPCAUTH_lockd,
1137         RPCAUTH_mount,
1138         RPCAUTH_nfs,
1139         RPCAUTH_portmap,
1140         RPCAUTH_statd,
1141         RPCAUTH_nfsd4_cb,
1142         RPCAUTH_cache,
1143         RPCAUTH_nfsd,
1144         RPCAUTH_gssd,
1145         RPCAUTH_RootEOF
1146 };
1147
1148 static const struct rpc_filelist files[] = {
1149         [RPCAUTH_lockd] = {
1150                 .name = "lockd",
1151                 .mode = S_IFDIR | 0555,
1152         },
1153         [RPCAUTH_mount] = {
1154                 .name = "mount",
1155                 .mode = S_IFDIR | 0555,
1156         },
1157         [RPCAUTH_nfs] = {
1158                 .name = "nfs",
1159                 .mode = S_IFDIR | 0555,
1160         },
1161         [RPCAUTH_portmap] = {
1162                 .name = "portmap",
1163                 .mode = S_IFDIR | 0555,
1164         },
1165         [RPCAUTH_statd] = {
1166                 .name = "statd",
1167                 .mode = S_IFDIR | 0555,
1168         },
1169         [RPCAUTH_nfsd4_cb] = {
1170                 .name = "nfsd4_cb",
1171                 .mode = S_IFDIR | 0555,
1172         },
1173         [RPCAUTH_cache] = {
1174                 .name = "cache",
1175                 .mode = S_IFDIR | 0555,
1176         },
1177         [RPCAUTH_nfsd] = {
1178                 .name = "nfsd",
1179                 .mode = S_IFDIR | 0555,
1180         },
1181         [RPCAUTH_gssd] = {
1182                 .name = "gssd",
1183                 .mode = S_IFDIR | 0555,
1184         },
1185 };
1186
1187 /*
1188  * This call can be used only in RPC pipefs mount notification hooks.
1189  */
1190 struct dentry *rpc_d_lookup_sb(const struct super_block *sb,
1191                                const unsigned char *dir_name)
1192 {
1193         struct qstr dir = QSTR_INIT(dir_name, strlen(dir_name));
1194         return d_hash_and_lookup(sb->s_root, &dir);
1195 }
1196 EXPORT_SYMBOL_GPL(rpc_d_lookup_sb);
1197
1198 int rpc_pipefs_init_net(struct net *net)
1199 {
1200         struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
1201
1202         sn->gssd_dummy = rpc_mkpipe_data(&gssd_dummy_pipe_ops, 0);
1203         if (IS_ERR(sn->gssd_dummy))
1204                 return PTR_ERR(sn->gssd_dummy);
1205
1206         mutex_init(&sn->pipefs_sb_lock);
1207         sn->pipe_version = -1;
1208         return 0;
1209 }
1210
1211 void rpc_pipefs_exit_net(struct net *net)
1212 {
1213         struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
1214
1215         rpc_destroy_pipe_data(sn->gssd_dummy);
1216 }
1217
1218 /*
1219  * This call will be used for per network namespace operations calls.
1220  * Note: Function will be returned with pipefs_sb_lock taken if superblock was
1221  * found. This lock have to be released by rpc_put_sb_net() when all operations
1222  * will be completed.
1223  */
1224 struct super_block *rpc_get_sb_net(const struct net *net)
1225 {
1226         struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
1227
1228         mutex_lock(&sn->pipefs_sb_lock);
1229         if (sn->pipefs_sb)
1230                 return sn->pipefs_sb;
1231         mutex_unlock(&sn->pipefs_sb_lock);
1232         return NULL;
1233 }
1234 EXPORT_SYMBOL_GPL(rpc_get_sb_net);
1235
1236 void rpc_put_sb_net(const struct net *net)
1237 {
1238         struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
1239
1240         WARN_ON(sn->pipefs_sb == NULL);
1241         mutex_unlock(&sn->pipefs_sb_lock);
1242 }
1243 EXPORT_SYMBOL_GPL(rpc_put_sb_net);
1244
1245 static const struct rpc_filelist gssd_dummy_clnt_dir[] = {
1246         [0] = {
1247                 .name = "clntXX",
1248                 .mode = S_IFDIR | 0555,
1249         },
1250 };
1251
1252 static ssize_t
1253 dummy_downcall(struct file *filp, const char __user *src, size_t len)
1254 {
1255         return -EINVAL;
1256 }
1257
1258 static const struct rpc_pipe_ops gssd_dummy_pipe_ops = {
1259         .upcall         = rpc_pipe_generic_upcall,
1260         .downcall       = dummy_downcall,
1261 };
1262
1263 /*
1264  * Here we present a bogus "info" file to keep rpc.gssd happy. We don't expect
1265  * that it will ever use this info to handle an upcall, but rpc.gssd expects
1266  * that this file will be there and have a certain format.
1267  */
1268 static int
1269 rpc_dummy_info_show(struct seq_file *m, void *v)
1270 {
1271         seq_printf(m, "RPC server: %s\n", utsname()->nodename);
1272         seq_printf(m, "service: foo (1) version 0\n");
1273         seq_printf(m, "address: 127.0.0.1\n");
1274         seq_printf(m, "protocol: tcp\n");
1275         seq_printf(m, "port: 0\n");
1276         return 0;
1277 }
1278 DEFINE_SHOW_ATTRIBUTE(rpc_dummy_info);
1279
1280 static const struct rpc_filelist gssd_dummy_info_file[] = {
1281         [0] = {
1282                 .name = "info",
1283                 .i_fop = &rpc_dummy_info_fops,
1284                 .mode = S_IFREG | 0400,
1285         },
1286 };
1287
1288 /**
1289  * rpc_gssd_dummy_populate - create a dummy gssd pipe
1290  * @root:       root of the rpc_pipefs filesystem
1291  * @pipe_data:  pipe data created when netns is initialized
1292  *
1293  * Create a dummy set of directories and a pipe that gssd can hold open to
1294  * indicate that it is up and running.
1295  */
1296 static struct dentry *
1297 rpc_gssd_dummy_populate(struct dentry *root, struct rpc_pipe *pipe_data)
1298 {
1299         int ret = 0;
1300         struct dentry *gssd_dentry;
1301         struct dentry *clnt_dentry = NULL;
1302         struct dentry *pipe_dentry = NULL;
1303         struct qstr q = QSTR_INIT(files[RPCAUTH_gssd].name,
1304                                   strlen(files[RPCAUTH_gssd].name));
1305
1306         /* We should never get this far if "gssd" doesn't exist */
1307         gssd_dentry = d_hash_and_lookup(root, &q);
1308         if (!gssd_dentry)
1309                 return ERR_PTR(-ENOENT);
1310
1311         ret = rpc_populate(gssd_dentry, gssd_dummy_clnt_dir, 0, 1, NULL);
1312         if (ret) {
1313                 pipe_dentry = ERR_PTR(ret);
1314                 goto out;
1315         }
1316
1317         q.name = gssd_dummy_clnt_dir[0].name;
1318         q.len = strlen(gssd_dummy_clnt_dir[0].name);
1319         clnt_dentry = d_hash_and_lookup(gssd_dentry, &q);
1320         if (!clnt_dentry) {
1321                 __rpc_depopulate(gssd_dentry, gssd_dummy_clnt_dir, 0, 1);
1322                 pipe_dentry = ERR_PTR(-ENOENT);
1323                 goto out;
1324         }
1325
1326         ret = rpc_populate(clnt_dentry, gssd_dummy_info_file, 0, 1, NULL);
1327         if (ret) {
1328                 __rpc_depopulate(gssd_dentry, gssd_dummy_clnt_dir, 0, 1);
1329                 pipe_dentry = ERR_PTR(ret);
1330                 goto out;
1331         }
1332
1333         pipe_dentry = rpc_mkpipe_dentry(clnt_dentry, "gssd", NULL, pipe_data);
1334         if (IS_ERR(pipe_dentry)) {
1335                 __rpc_depopulate(clnt_dentry, gssd_dummy_info_file, 0, 1);
1336                 __rpc_depopulate(gssd_dentry, gssd_dummy_clnt_dir, 0, 1);
1337         }
1338 out:
1339         dput(clnt_dentry);
1340         dput(gssd_dentry);
1341         return pipe_dentry;
1342 }
1343
1344 static void
1345 rpc_gssd_dummy_depopulate(struct dentry *pipe_dentry)
1346 {
1347         struct dentry *clnt_dir = pipe_dentry->d_parent;
1348         struct dentry *gssd_dir = clnt_dir->d_parent;
1349
1350         dget(pipe_dentry);
1351         __rpc_rmpipe(d_inode(clnt_dir), pipe_dentry);
1352         __rpc_depopulate(clnt_dir, gssd_dummy_info_file, 0, 1);
1353         __rpc_depopulate(gssd_dir, gssd_dummy_clnt_dir, 0, 1);
1354         dput(pipe_dentry);
1355 }
1356
1357 static int
1358 rpc_fill_super(struct super_block *sb, struct fs_context *fc)
1359 {
1360         struct inode *inode;
1361         struct dentry *root, *gssd_dentry;
1362         struct net *net = sb->s_fs_info;
1363         struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
1364         int err;
1365
1366         sb->s_blocksize = PAGE_SIZE;
1367         sb->s_blocksize_bits = PAGE_SHIFT;
1368         sb->s_magic = RPCAUTH_GSSMAGIC;
1369         sb->s_op = &s_ops;
1370         sb->s_d_op = &simple_dentry_operations;
1371         sb->s_time_gran = 1;
1372
1373         inode = rpc_get_inode(sb, S_IFDIR | 0555);
1374         sb->s_root = root = d_make_root(inode);
1375         if (!root)
1376                 return -ENOMEM;
1377         if (rpc_populate(root, files, RPCAUTH_lockd, RPCAUTH_RootEOF, NULL))
1378                 return -ENOMEM;
1379
1380         gssd_dentry = rpc_gssd_dummy_populate(root, sn->gssd_dummy);
1381         if (IS_ERR(gssd_dentry)) {
1382                 __rpc_depopulate(root, files, RPCAUTH_lockd, RPCAUTH_RootEOF);
1383                 return PTR_ERR(gssd_dentry);
1384         }
1385
1386         dprintk("RPC:       sending pipefs MOUNT notification for net %x%s\n",
1387                 net->ns.inum, NET_NAME(net));
1388         mutex_lock(&sn->pipefs_sb_lock);
1389         sn->pipefs_sb = sb;
1390         err = blocking_notifier_call_chain(&rpc_pipefs_notifier_list,
1391                                            RPC_PIPEFS_MOUNT,
1392                                            sb);
1393         if (err)
1394                 goto err_depopulate;
1395         mutex_unlock(&sn->pipefs_sb_lock);
1396         return 0;
1397
1398 err_depopulate:
1399         rpc_gssd_dummy_depopulate(gssd_dentry);
1400         blocking_notifier_call_chain(&rpc_pipefs_notifier_list,
1401                                            RPC_PIPEFS_UMOUNT,
1402                                            sb);
1403         sn->pipefs_sb = NULL;
1404         __rpc_depopulate(root, files, RPCAUTH_lockd, RPCAUTH_RootEOF);
1405         mutex_unlock(&sn->pipefs_sb_lock);
1406         return err;
1407 }
1408
1409 bool
1410 gssd_running(struct net *net)
1411 {
1412         struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
1413         struct rpc_pipe *pipe = sn->gssd_dummy;
1414
1415         return pipe->nreaders || pipe->nwriters;
1416 }
1417 EXPORT_SYMBOL_GPL(gssd_running);
1418
1419 static int rpc_fs_get_tree(struct fs_context *fc)
1420 {
1421         return get_tree_keyed(fc, rpc_fill_super, get_net(fc->net_ns));
1422 }
1423
1424 static void rpc_fs_free_fc(struct fs_context *fc)
1425 {
1426         if (fc->s_fs_info)
1427                 put_net(fc->s_fs_info);
1428 }
1429
1430 static const struct fs_context_operations rpc_fs_context_ops = {
1431         .free           = rpc_fs_free_fc,
1432         .get_tree       = rpc_fs_get_tree,
1433 };
1434
1435 static int rpc_init_fs_context(struct fs_context *fc)
1436 {
1437         put_user_ns(fc->user_ns);
1438         fc->user_ns = get_user_ns(fc->net_ns->user_ns);
1439         fc->ops = &rpc_fs_context_ops;
1440         return 0;
1441 }
1442
1443 static void rpc_kill_sb(struct super_block *sb)
1444 {
1445         struct net *net = sb->s_fs_info;
1446         struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
1447
1448         mutex_lock(&sn->pipefs_sb_lock);
1449         if (sn->pipefs_sb != sb) {
1450                 mutex_unlock(&sn->pipefs_sb_lock);
1451                 goto out;
1452         }
1453         sn->pipefs_sb = NULL;
1454         dprintk("RPC:       sending pipefs UMOUNT notification for net %x%s\n",
1455                 net->ns.inum, NET_NAME(net));
1456         blocking_notifier_call_chain(&rpc_pipefs_notifier_list,
1457                                            RPC_PIPEFS_UMOUNT,
1458                                            sb);
1459         mutex_unlock(&sn->pipefs_sb_lock);
1460 out:
1461         kill_litter_super(sb);
1462         put_net(net);
1463 }
1464
1465 static struct file_system_type rpc_pipe_fs_type = {
1466         .owner          = THIS_MODULE,
1467         .name           = "rpc_pipefs",
1468         .init_fs_context = rpc_init_fs_context,
1469         .kill_sb        = rpc_kill_sb,
1470 };
1471 MODULE_ALIAS_FS("rpc_pipefs");
1472 MODULE_ALIAS("rpc_pipefs");
1473
1474 static void
1475 init_once(void *foo)
1476 {
1477         struct rpc_inode *rpci = (struct rpc_inode *) foo;
1478
1479         inode_init_once(&rpci->vfs_inode);
1480         rpci->private = NULL;
1481         rpci->pipe = NULL;
1482         init_waitqueue_head(&rpci->waitq);
1483 }
1484
1485 int register_rpc_pipefs(void)
1486 {
1487         int err;
1488
1489         rpc_inode_cachep = kmem_cache_create("rpc_inode_cache",
1490                                 sizeof(struct rpc_inode),
1491                                 0, (SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT|
1492                                                 SLAB_MEM_SPREAD|SLAB_ACCOUNT),
1493                                 init_once);
1494         if (!rpc_inode_cachep)
1495                 return -ENOMEM;
1496         err = rpc_clients_notifier_register();
1497         if (err)
1498                 goto err_notifier;
1499         err = register_filesystem(&rpc_pipe_fs_type);
1500         if (err)
1501                 goto err_register;
1502         return 0;
1503
1504 err_register:
1505         rpc_clients_notifier_unregister();
1506 err_notifier:
1507         kmem_cache_destroy(rpc_inode_cachep);
1508         return err;
1509 }
1510
1511 void unregister_rpc_pipefs(void)
1512 {
1513         rpc_clients_notifier_unregister();
1514         unregister_filesystem(&rpc_pipe_fs_type);
1515         kmem_cache_destroy(rpc_inode_cachep);
1516 }