Pileus Git - ~andy/linux/blob - net/sunrpc/rpc_pipe.c

   1 /*
   2  * net/sunrpc/rpc_pipe.c
   3  *
   4  * Userland/kernel interface for rpcauth_gss.
   5  * Code shamelessly plagiarized from fs/nfsd/nfsctl.c
   6  * and fs/sysfs/inode.c
   7  *
   8  * Copyright (c) 2002, Trond Myklebust <trond.myklebust@fys.uio.no>
   9  *
  10  */
  11 #include <linux/module.h>
  12 #include <linux/slab.h>
  13 #include <linux/string.h>
  14 #include <linux/pagemap.h>
  15 #include <linux/mount.h>
  16 #include <linux/namei.h>
  17 #include <linux/fsnotify.h>
  18 #include <linux/kernel.h>
  19 #include <linux/rcupdate.h>
  20
  21 #include <asm/ioctls.h>
  22 #include <linux/poll.h>
  23 #include <linux/wait.h>
  24 #include <linux/seq_file.h>
  25
  26 #include <linux/sunrpc/clnt.h>
  27 #include <linux/workqueue.h>
  28 #include <linux/sunrpc/rpc_pipe_fs.h>
  29 #include <linux/sunrpc/cache.h>
  30 #include <linux/nsproxy.h>
  31 #include <linux/notifier.h>
  32
  33 #include "netns.h"
  34 #include "sunrpc.h"
  35
  36 #define RPCDBG_FACILITY RPCDBG_DEBUG
  37
  38 #define NET_NAME(net)   ((net == &init_net) ? " (init_net)" : "")
  39
  40 static struct file_system_type rpc_pipe_fs_type;
  41
  42
  43 static struct kmem_cache *rpc_inode_cachep __read_mostly;
  44
  45 #define RPC_UPCALL_TIMEOUT (30*HZ)
  46
  47 static BLOCKING_NOTIFIER_HEAD(rpc_pipefs_notifier_list);
  48
  49 int rpc_pipefs_notifier_register(struct notifier_block *nb)
  50 {
  51         return blocking_notifier_chain_cond_register(&rpc_pipefs_notifier_list, nb);
  52 }
  53 EXPORT_SYMBOL_GPL(rpc_pipefs_notifier_register);
  54
  55 void rpc_pipefs_notifier_unregister(struct notifier_block *nb)
  56 {
  57         blocking_notifier_chain_unregister(&rpc_pipefs_notifier_list, nb);
  58 }
  59 EXPORT_SYMBOL_GPL(rpc_pipefs_notifier_unregister);
  60
  61 static void rpc_purge_list(wait_queue_head_t *waitq, struct list_head *head,
  62                 void (*destroy_msg)(struct rpc_pipe_msg *), int err)
  63 {
  64         struct rpc_pipe_msg *msg;
  65
  66         if (list_empty(head))
  67                 return;
  68         do {
  69                 msg = list_entry(head->next, struct rpc_pipe_msg, list);
  70                 list_del_init(&msg->list);
  71                 msg->errno = err;
  72                 destroy_msg(msg);
  73         } while (!list_empty(head));
  74         wake_up(waitq);
  75 }
  76
  77 static void
  78 rpc_timeout_upcall_queue(struct work_struct *work)
  79 {
  80         LIST_HEAD(free_list);
  81         struct rpc_pipe *pipe =
  82                 container_of(work, struct rpc_pipe, queue_timeout.work);
  83         void (*destroy_msg)(struct rpc_pipe_msg *);
  84         struct dentry *dentry;
  85
  86         spin_lock(&pipe->lock);
  87         destroy_msg = pipe->ops->destroy_msg;
  88         if (pipe->nreaders == 0) {
  89                 list_splice_init(&pipe->pipe, &free_list);
  90                 pipe->pipelen = 0;
  91         }
  92         dentry = dget(pipe->dentry);
  93         spin_unlock(&pipe->lock);
  94         if (dentry) {
  95                 rpc_purge_list(&RPC_I(dentry->d_inode)->waitq,
  96                                &free_list, destroy_msg, -ETIMEDOUT);
  97                 dput(dentry);
  98         }
  99 }
 100
 101 ssize_t rpc_pipe_generic_upcall(struct file *filp, struct rpc_pipe_msg *msg,
 102                                 char __user *dst, size_t buflen)
 103 {
 104         char *data = (char *)msg->data + msg->copied;
 105         size_t mlen = min(msg->len - msg->copied, buflen);
 106         unsigned long left;
 107
 108         left = copy_to_user(dst, data, mlen);
 109         if (left == mlen) {
 110                 msg->errno = -EFAULT;
 111                 return -EFAULT;
 112         }
 113
 114         mlen -= left;
 115         msg->copied += mlen;
 116         msg->errno = 0;
 117         return mlen;
 118 }
 119 EXPORT_SYMBOL_GPL(rpc_pipe_generic_upcall);
 120
 121 /**
 122  * rpc_queue_upcall - queue an upcall message to userspace
 123  * @inode: inode of upcall pipe on which to queue given message
 124  * @msg: message to queue
 125  *
 126  * Call with an @inode created by rpc_mkpipe() to queue an upcall.
 127  * A userspace process may then later read the upcall by performing a
 128  * read on an open file for this inode.  It is up to the caller to
 129  * initialize the fields of @msg (other than @msg->list) appropriately.
 130  */
 131 int
 132 rpc_queue_upcall(struct rpc_pipe *pipe, struct rpc_pipe_msg *msg)
 133 {
 134         int res = -EPIPE;
 135         struct dentry *dentry;
 136
 137         spin_lock(&pipe->lock);
 138         if (pipe->nreaders) {
 139                 list_add_tail(&msg->list, &pipe->pipe);
 140                 pipe->pipelen += msg->len;
 141                 res = 0;
 142         } else if (pipe->flags & RPC_PIPE_WAIT_FOR_OPEN) {
 143                 if (list_empty(&pipe->pipe))
 144                         queue_delayed_work(rpciod_workqueue,
 145                                         &pipe->queue_timeout,
 146                                         RPC_UPCALL_TIMEOUT);
 147                 list_add_tail(&msg->list, &pipe->pipe);
 148                 pipe->pipelen += msg->len;
 149                 res = 0;
 150         }
 151         dentry = dget(pipe->dentry);
 152         spin_unlock(&pipe->lock);
 153         if (dentry) {
 154                 wake_up(&RPC_I(dentry->d_inode)->waitq);
 155                 dput(dentry);
 156         }
 157         return res;
 158 }
 159 EXPORT_SYMBOL_GPL(rpc_queue_upcall);
 160
 161 static inline void
 162 rpc_inode_setowner(struct inode *inode, void *private)
 163 {
 164         RPC_I(inode)->private = private;
 165 }
 166
 167 static void
 168 rpc_close_pipes(struct inode *inode)
 169 {
 170         struct rpc_pipe *pipe = RPC_I(inode)->pipe;
 171         int need_release;
 172         LIST_HEAD(free_list);
 173
 174         mutex_lock(&inode->i_mutex);
 175         spin_lock(&pipe->lock);
 176         need_release = pipe->nreaders != 0 || pipe->nwriters != 0;
 177         pipe->nreaders = 0;
 178         list_splice_init(&pipe->in_upcall, &free_list);
 179         list_splice_init(&pipe->pipe, &free_list);
 180         pipe->pipelen = 0;
 181         pipe->dentry = NULL;
 182         spin_unlock(&pipe->lock);
 183         rpc_purge_list(&RPC_I(inode)->waitq, &free_list, pipe->ops->destroy_msg, -EPIPE);
 184         pipe->nwriters = 0;
 185         if (need_release && pipe->ops->release_pipe)
 186                 pipe->ops->release_pipe(inode);
 187         cancel_delayed_work_sync(&pipe->queue_timeout);
 188         rpc_inode_setowner(inode, NULL);
 189         RPC_I(inode)->pipe = NULL;
 190         mutex_unlock(&inode->i_mutex);
 191 }
 192
 193 static struct inode *
 194 rpc_alloc_inode(struct super_block *sb)
 195 {
 196         struct rpc_inode *rpci;
 197         rpci = (struct rpc_inode *)kmem_cache_alloc(rpc_inode_cachep, GFP_KERNEL);
 198         if (!rpci)
 199                 return NULL;
 200         return &rpci->vfs_inode;
 201 }
 202
 203 static void
 204 rpc_i_callback(struct rcu_head *head)
 205 {
 206         struct inode *inode = container_of(head, struct inode, i_rcu);
 207         kmem_cache_free(rpc_inode_cachep, RPC_I(inode));
 208 }
 209
 210 static void
 211 rpc_destroy_inode(struct inode *inode)
 212 {
 213         call_rcu(&inode->i_rcu, rpc_i_callback);
 214 }
 215
 216 static int
 217 rpc_pipe_open(struct inode *inode, struct file *filp)
 218 {
 219         struct rpc_pipe *pipe;
 220         int first_open;
 221         int res = -ENXIO;
 222
 223         mutex_lock(&inode->i_mutex);
 224         pipe = RPC_I(inode)->pipe;
 225         if (pipe == NULL)
 226                 goto out;
 227         first_open = pipe->nreaders == 0 && pipe->nwriters == 0;
 228         if (first_open && pipe->ops->open_pipe) {
 229                 res = pipe->ops->open_pipe(inode);
 230                 if (res)
 231                         goto out;
 232         }
 233         if (filp->f_mode & FMODE_READ)
 234                 pipe->nreaders++;
 235         if (filp->f_mode & FMODE_WRITE)
 236                 pipe->nwriters++;
 237         res = 0;
 238 out:
 239         mutex_unlock(&inode->i_mutex);
 240         return res;
 241 }
 242
 243 static int
 244 rpc_pipe_release(struct inode *inode, struct file *filp)
 245 {
 246         struct rpc_pipe *pipe;
 247         struct rpc_pipe_msg *msg;
 248         int last_close;
 249
 250         mutex_lock(&inode->i_mutex);
 251         pipe = RPC_I(inode)->pipe;
 252         if (pipe == NULL)
 253                 goto out;
 254         msg = filp->private_data;
 255         if (msg != NULL) {
 256                 spin_lock(&pipe->lock);
 257                 msg->errno = -EAGAIN;
 258                 list_del_init(&msg->list);
 259                 spin_unlock(&pipe->lock);
 260                 pipe->ops->destroy_msg(msg);
 261         }
 262         if (filp->f_mode & FMODE_WRITE)
 263                 pipe->nwriters --;
 264         if (filp->f_mode & FMODE_READ) {
 265                 pipe->nreaders --;
 266                 if (pipe->nreaders == 0) {
 267                         LIST_HEAD(free_list);
 268                         spin_lock(&pipe->lock);
 269                         list_splice_init(&pipe->pipe, &free_list);
 270                         pipe->pipelen = 0;
 271                         spin_unlock(&pipe->lock);
 272                         rpc_purge_list(&RPC_I(inode)->waitq, &free_list,
 273                                         pipe->ops->destroy_msg, -EAGAIN);
 274                 }
 275         }
 276         last_close = pipe->nwriters == 0 && pipe->nreaders == 0;
 277         if (last_close && pipe->ops->release_pipe)
 278                 pipe->ops->release_pipe(inode);
 279 out:
 280         mutex_unlock(&inode->i_mutex);
 281         return 0;
 282 }
 283
 284 static ssize_t
 285 rpc_pipe_read(struct file *filp, char __user *buf, size_t len, loff_t *offset)
 286 {
 287         struct inode *inode = filp->f_path.dentry->d_inode;
 288         struct rpc_pipe *pipe;
 289         struct rpc_pipe_msg *msg;
 290         int res = 0;
 291
 292         mutex_lock(&inode->i_mutex);
 293         pipe = RPC_I(inode)->pipe;
 294         if (pipe == NULL) {
 295                 res = -EPIPE;
 296                 goto out_unlock;
 297         }
 298         msg = filp->private_data;
 299         if (msg == NULL) {
 300                 spin_lock(&pipe->lock);
 301                 if (!list_empty(&pipe->pipe)) {
 302                         msg = list_entry(pipe->pipe.next,
 303                                         struct rpc_pipe_msg,
 304                                         list);
 305                         list_move(&msg->list, &pipe->in_upcall);
 306                         pipe->pipelen -= msg->len;
 307                         filp->private_data = msg;
 308                         msg->copied = 0;
 309                 }
 310                 spin_unlock(&pipe->lock);
 311                 if (msg == NULL)
 312                         goto out_unlock;
 313         }
 314         /* NOTE: it is up to the callback to update msg->copied */
 315         res = pipe->ops->upcall(filp, msg, buf, len);
 316         if (res < 0 || msg->len == msg->copied) {
 317                 filp->private_data = NULL;
 318                 spin_lock(&pipe->lock);
 319                 list_del_init(&msg->list);
 320                 spin_unlock(&pipe->lock);
 321                 pipe->ops->destroy_msg(msg);
 322         }
 323 out_unlock:
 324         mutex_unlock(&inode->i_mutex);
 325         return res;
 326 }
 327
 328 static ssize_t
 329 rpc_pipe_write(struct file *filp, const char __user *buf, size_t len, loff_t *offset)
 330 {
 331         struct inode *inode = filp->f_path.dentry->d_inode;
 332         int res;
 333
 334         mutex_lock(&inode->i_mutex);
 335         res = -EPIPE;
 336         if (RPC_I(inode)->pipe != NULL)
 337                 res = RPC_I(inode)->pipe->ops->downcall(filp, buf, len);
 338         mutex_unlock(&inode->i_mutex);
 339         return res;
 340 }
 341
 342 static unsigned int
 343 rpc_pipe_poll(struct file *filp, struct poll_table_struct *wait)
 344 {
 345         struct inode *inode = filp->f_path.dentry->d_inode;
 346         struct rpc_inode *rpci = RPC_I(inode);
 347         unsigned int mask = POLLOUT | POLLWRNORM;
 348
 349         poll_wait(filp, &rpci->waitq, wait);
 350
 351         mutex_lock(&inode->i_mutex);
 352         if (rpci->pipe == NULL)
 353                 mask |= POLLERR | POLLHUP;
 354         else if (filp->private_data || !list_empty(&rpci->pipe->pipe))
 355                 mask |= POLLIN | POLLRDNORM;
 356         mutex_unlock(&inode->i_mutex);
 357         return mask;
 358 }
 359
 360 static long
 361 rpc_pipe_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 362 {
 363         struct inode *inode = filp->f_path.dentry->d_inode;
 364         struct rpc_pipe *pipe;
 365         int len;
 366
 367         switch (cmd) {
 368         case FIONREAD:
 369                 mutex_lock(&inode->i_mutex);
 370                 pipe = RPC_I(inode)->pipe;
 371                 if (pipe == NULL) {
 372                         mutex_unlock(&inode->i_mutex);
 373                         return -EPIPE;
 374                 }
 375                 spin_lock(&pipe->lock);
 376                 len = pipe->pipelen;
 377                 if (filp->private_data) {
 378                         struct rpc_pipe_msg *msg;
 379                         msg = filp->private_data;
 380                         len += msg->len - msg->copied;
 381                 }
 382                 spin_unlock(&pipe->lock);
 383                 mutex_unlock(&inode->i_mutex);
 384                 return put_user(len, (int __user *)arg);
 385         default:
 386                 return -EINVAL;
 387         }
 388 }
 389
 390 static const struct file_operations rpc_pipe_fops = {
 391         .owner          = THIS_MODULE,
 392         .llseek         = no_llseek,
 393         .read           = rpc_pipe_read,
 394         .write          = rpc_pipe_write,
 395         .poll           = rpc_pipe_poll,
 396         .unlocked_ioctl = rpc_pipe_ioctl,
 397         .open           = rpc_pipe_open,
 398         .release        = rpc_pipe_release,
 399 };
 400
 401 static int
 402 rpc_show_info(struct seq_file *m, void *v)
 403 {
 404         struct rpc_clnt *clnt = m->private;
 405
 406         rcu_read_lock();
 407         seq_printf(m, "RPC server: %s\n", clnt->cl_server);
 408         seq_printf(m, "service: %s (%d) version %d\n", clnt->cl_protname,
 409                         clnt->cl_prog, clnt->cl_vers);
 410         seq_printf(m, "address: %s\n", rpc_peeraddr2str(clnt, RPC_DISPLAY_ADDR));
 411         seq_printf(m, "protocol: %s\n", rpc_peeraddr2str(clnt, RPC_DISPLAY_PROTO));
 412         seq_printf(m, "port: %s\n", rpc_peeraddr2str(clnt, RPC_DISPLAY_PORT));
 413         rcu_read_unlock();
 414         return 0;
 415 }
 416
 417 static int
 418 rpc_info_open(struct inode *inode, struct file *file)
 419 {
 420         struct rpc_clnt *clnt = NULL;
 421         int ret = single_open(file, rpc_show_info, NULL);
 422
 423         if (!ret) {
 424                 struct seq_file *m = file->private_data;
 425
 426                 spin_lock(&file->f_path.dentry->d_lock);
 427                 if (!d_unhashed(file->f_path.dentry))
 428                         clnt = RPC_I(inode)->private;
 429                 if (clnt != NULL && atomic_inc_not_zero(&clnt->cl_count)) {
 430                         spin_unlock(&file->f_path.dentry->d_lock);
 431                         m->private = clnt;
 432                 } else {
 433                         spin_unlock(&file->f_path.dentry->d_lock);
 434                         single_release(inode, file);
 435                         ret = -EINVAL;
 436                 }
 437         }
 438         return ret;
 439 }
 440
 441 static int
 442 rpc_info_release(struct inode *inode, struct file *file)
 443 {
 444         struct seq_file *m = file->private_data;
 445         struct rpc_clnt *clnt = (struct rpc_clnt *)m->private;
 446
 447         if (clnt)
 448                 rpc_release_client(clnt);
 449         return single_release(inode, file);
 450 }
 451
 452 static const struct file_operations rpc_info_operations = {
 453         .owner          = THIS_MODULE,
 454         .open           = rpc_info_open,
 455         .read           = seq_read,
 456         .llseek         = seq_lseek,
 457         .release        = rpc_info_release,
 458 };
 459
 460
 461 /*
 462  * Description of fs contents.
 463  */
 464 struct rpc_filelist {
 465         const char *name;
 466         const struct file_operations *i_fop;
 467         umode_t mode;
 468 };
 469
 470 static int rpc_delete_dentry(const struct dentry *dentry)
 471 {
 472         return 1;
 473 }
 474
 475 static const struct dentry_operations rpc_dentry_operations = {
 476         .d_delete = rpc_delete_dentry,
 477 };
 478
 479 static struct inode *
 480 rpc_get_inode(struct super_block *sb, umode_t mode)
 481 {
 482         struct inode *inode = new_inode(sb);
 483         if (!inode)
 484                 return NULL;
 485         inode->i_ino = get_next_ino();
 486         inode->i_mode = mode;
 487         inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
 488         switch (mode & S_IFMT) {
 489         case S_IFDIR:
 490                 inode->i_fop = &simple_dir_operations;
 491                 inode->i_op = &simple_dir_inode_operations;
 492                 inc_nlink(inode);
 493         default:
 494                 break;
 495         }
 496         return inode;
 497 }
 498
 499 static int __rpc_create_common(struct inode *dir, struct dentry *dentry,
 500                                umode_t mode,
 501                                const struct file_operations *i_fop,
 502                                void *private)
 503 {
 504         struct inode *inode;
 505
 506         d_drop(dentry);
 507         inode = rpc_get_inode(dir->i_sb, mode);
 508         if (!inode)
 509                 goto out_err;
 510         inode->i_ino = iunique(dir->i_sb, 100);
 511         if (i_fop)
 512                 inode->i_fop = i_fop;
 513         if (private)
 514                 rpc_inode_setowner(inode, private);
 515         d_add(dentry, inode);
 516         return 0;
 517 out_err:
 518         printk(KERN_WARNING "%s: %s failed to allocate inode for dentry %s\n",
 519                         __FILE__, __func__, dentry->d_name.name);
 520         dput(dentry);
 521         return -ENOMEM;
 522 }
 523
 524 static int __rpc_create(struct inode *dir, struct dentry *dentry,
 525                         umode_t mode,
 526                         const struct file_operations *i_fop,
 527                         void *private)
 528 {
 529         int err;
 530
 531         err = __rpc_create_common(dir, dentry, S_IFREG | mode, i_fop, private);
 532         if (err)
 533                 return err;
 534         fsnotify_create(dir, dentry);
 535         return 0;
 536 }
 537
 538 static int __rpc_mkdir(struct inode *dir, struct dentry *dentry,
 539                        umode_t mode,
 540                        const struct file_operations *i_fop,
 541                        void *private)
 542 {
 543         int err;
 544
 545         err = __rpc_create_common(dir, dentry, S_IFDIR | mode, i_fop, private);
 546         if (err)
 547                 return err;
 548         inc_nlink(dir);
 549         fsnotify_mkdir(dir, dentry);
 550         return 0;
 551 }
 552
 553 static void
 554 init_pipe(struct rpc_pipe *pipe)
 555 {
 556         pipe->nreaders = 0;
 557         pipe->nwriters = 0;
 558         INIT_LIST_HEAD(&pipe->in_upcall);
 559         INIT_LIST_HEAD(&pipe->in_downcall);
 560         INIT_LIST_HEAD(&pipe->pipe);
 561         pipe->pipelen = 0;
 562         INIT_DELAYED_WORK(&pipe->queue_timeout,
 563                             rpc_timeout_upcall_queue);
 564         pipe->ops = NULL;
 565         spin_lock_init(&pipe->lock);
 566         pipe->dentry = NULL;
 567 }
 568
 569 void rpc_destroy_pipe_data(struct rpc_pipe *pipe)
 570 {
 571         kfree(pipe);
 572 }
 573 EXPORT_SYMBOL_GPL(rpc_destroy_pipe_data);
 574
 575 struct rpc_pipe *rpc_mkpipe_data(const struct rpc_pipe_ops *ops, int flags)
 576 {
 577         struct rpc_pipe *pipe;
 578
 579         pipe = kzalloc(sizeof(struct rpc_pipe), GFP_KERNEL);
 580         if (!pipe)
 581                 return ERR_PTR(-ENOMEM);
 582         init_pipe(pipe);
 583         pipe->ops = ops;
 584         pipe->flags = flags;
 585         return pipe;
 586 }
 587 EXPORT_SYMBOL_GPL(rpc_mkpipe_data);
 588
 589 static int __rpc_mkpipe_dentry(struct inode *dir, struct dentry *dentry,
 590                                umode_t mode,
 591                                const struct file_operations *i_fop,
 592                                void *private,
 593                                struct rpc_pipe *pipe)
 594 {
 595         struct rpc_inode *rpci;
 596         int err;
 597
 598         err = __rpc_create_common(dir, dentry, S_IFIFO | mode, i_fop, private);
 599         if (err)
 600                 return err;
 601         rpci = RPC_I(dentry->d_inode);
 602         rpci->private = private;
 603         rpci->pipe = pipe;
 604         fsnotify_create(dir, dentry);
 605         return 0;
 606 }
 607
 608 static int __rpc_rmdir(struct inode *dir, struct dentry *dentry)
 609 {
 610         int ret;
 611
 612         dget(dentry);
 613         ret = simple_rmdir(dir, dentry);
 614         d_delete(dentry);
 615         dput(dentry);
 616         return ret;
 617 }
 618
 619 int rpc_rmdir(struct dentry *dentry)
 620 {
 621         struct dentry *parent;
 622         struct inode *dir;
 623         int error;
 624
 625         parent = dget_parent(dentry);
 626         dir = parent->d_inode;
 627         mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
 628         error = __rpc_rmdir(dir, dentry);
 629         mutex_unlock(&dir->i_mutex);
 630         dput(parent);
 631         return error;
 632 }
 633 EXPORT_SYMBOL_GPL(rpc_rmdir);
 634
 635 static int __rpc_unlink(struct inode *dir, struct dentry *dentry)
 636 {
 637         int ret;
 638
 639         dget(dentry);
 640         ret = simple_unlink(dir, dentry);
 641         d_delete(dentry);
 642         dput(dentry);
 643         return ret;
 644 }
 645
 646 static int __rpc_rmpipe(struct inode *dir, struct dentry *dentry)
 647 {
 648         struct inode *inode = dentry->d_inode;
 649
 650         rpc_close_pipes(inode);
 651         return __rpc_unlink(dir, dentry);
 652 }
 653
 654 static struct dentry *__rpc_lookup_create_exclusive(struct dentry *parent,
 655                                           struct qstr *name)
 656 {
 657         struct dentry *dentry;
 658
 659         dentry = d_lookup(parent, name);
 660         if (!dentry) {
 661                 dentry = d_alloc(parent, name);
 662                 if (!dentry)
 663                         return ERR_PTR(-ENOMEM);
 664         }
 665         if (dentry->d_inode == NULL) {
 666                 d_set_d_op(dentry, &rpc_dentry_operations);
 667                 return dentry;
 668         }
 669         dput(dentry);
 670         return ERR_PTR(-EEXIST);
 671 }
 672
 673 /*
 674  * FIXME: This probably has races.
 675  */
 676 static void __rpc_depopulate(struct dentry *parent,
 677                              const struct rpc_filelist *files,
 678                              int start, int eof)
 679 {
 680         struct inode *dir = parent->d_inode;
 681         struct dentry *dentry;
 682         struct qstr name;
 683         int i;
 684
 685         for (i = start; i < eof; i++) {
 686                 name.name = files[i].name;
 687                 name.len = strlen(files[i].name);
 688                 name.hash = full_name_hash(name.name, name.len);
 689                 dentry = d_lookup(parent, &name);
 690
 691                 if (dentry == NULL)
 692                         continue;
 693                 if (dentry->d_inode == NULL)
 694                         goto next;
 695                 switch (dentry->d_inode->i_mode & S_IFMT) {
 696                         default:
 697                                 BUG();
 698                         case S_IFREG:
 699                                 __rpc_unlink(dir, dentry);
 700                                 break;
 701                         case S_IFDIR:
 702                                 __rpc_rmdir(dir, dentry);
 703                 }
 704 next:
 705                 dput(dentry);
 706         }
 707 }
 708
 709 static void rpc_depopulate(struct dentry *parent,
 710                            const struct rpc_filelist *files,
 711                            int start, int eof)
 712 {
 713         struct inode *dir = parent->d_inode;
 714
 715         mutex_lock_nested(&dir->i_mutex, I_MUTEX_CHILD);
 716         __rpc_depopulate(parent, files, start, eof);
 717         mutex_unlock(&dir->i_mutex);
 718 }
 719
 720 static int rpc_populate(struct dentry *parent,
 721                         const struct rpc_filelist *files,
 722                         int start, int eof,
 723                         void *private)
 724 {
 725         struct inode *dir = parent->d_inode;
 726         struct dentry *dentry;
 727         int i, err;
 728
 729         mutex_lock(&dir->i_mutex);
 730         for (i = start; i < eof; i++) {
 731                 struct qstr q;
 732
 733                 q.name = files[i].name;
 734                 q.len = strlen(files[i].name);
 735                 q.hash = full_name_hash(q.name, q.len);
 736                 dentry = __rpc_lookup_create_exclusive(parent, &q);
 737                 err = PTR_ERR(dentry);
 738                 if (IS_ERR(dentry))
 739                         goto out_bad;
 740                 switch (files[i].mode & S_IFMT) {
 741                         default:
 742                                 BUG();
 743                         case S_IFREG:
 744                                 err = __rpc_create(dir, dentry,
 745                                                 files[i].mode,
 746                                                 files[i].i_fop,
 747                                                 private);
 748                                 break;
 749                         case S_IFDIR:
 750                                 err = __rpc_mkdir(dir, dentry,
 751                                                 files[i].mode,
 752                                                 NULL,
 753                                                 private);
 754                 }
 755                 if (err != 0)
 756                         goto out_bad;
 757         }
 758         mutex_unlock(&dir->i_mutex);
 759         return 0;
 760 out_bad:
 761         __rpc_depopulate(parent, files, start, eof);
 762         mutex_unlock(&dir->i_mutex);
 763         printk(KERN_WARNING "%s: %s failed to populate directory %s\n",
 764                         __FILE__, __func__, parent->d_name.name);
 765         return err;
 766 }
 767
 768 static struct dentry *rpc_mkdir_populate(struct dentry *parent,
 769                 struct qstr *name, umode_t mode, void *private,
 770                 int (*populate)(struct dentry *, void *), void *args_populate)
 771 {
 772         struct dentry *dentry;
 773         struct inode *dir = parent->d_inode;
 774         int error;
 775
 776         mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
 777         dentry = __rpc_lookup_create_exclusive(parent, name);
 778         if (IS_ERR(dentry))
 779                 goto out;
 780         error = __rpc_mkdir(dir, dentry, mode, NULL, private);
 781         if (error != 0)
 782                 goto out_err;
 783         if (populate != NULL) {
 784                 error = populate(dentry, args_populate);
 785                 if (error)
 786                         goto err_rmdir;
 787         }
 788 out:
 789         mutex_unlock(&dir->i_mutex);
 790         return dentry;
 791 err_rmdir:
 792         __rpc_rmdir(dir, dentry);
 793 out_err:
 794         dentry = ERR_PTR(error);
 795         goto out;
 796 }
 797
 798 static int rpc_rmdir_depopulate(struct dentry *dentry,
 799                 void (*depopulate)(struct dentry *))
 800 {
 801         struct dentry *parent;
 802         struct inode *dir;
 803         int error;
 804
 805         parent = dget_parent(dentry);
 806         dir = parent->d_inode;
 807         mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
 808         if (depopulate != NULL)
 809                 depopulate(dentry);
 810         error = __rpc_rmdir(dir, dentry);
 811         mutex_unlock(&dir->i_mutex);
 812         dput(parent);
 813         return error;
 814 }
 815
 816 /**
 817  * rpc_mkpipe - make an rpc_pipefs file for kernel<->userspace communication
 818  * @parent: dentry of directory to create new "pipe" in
 819  * @name: name of pipe
 820  * @private: private data to associate with the pipe, for the caller's use
 821  * @ops: operations defining the behavior of the pipe: upcall, downcall,
 822  *      release_pipe, open_pipe, and destroy_msg.
 823  * @flags: rpc_pipe flags
 824  *
 825  * Data is made available for userspace to read by calls to
 826  * rpc_queue_upcall().  The actual reads will result in calls to
 827  * @ops->upcall, which will be called with the file pointer,
 828  * message, and userspace buffer to copy to.
 829  *
 830  * Writes can come at any time, and do not necessarily have to be
 831  * responses to upcalls.  They will result in calls to @msg->downcall.
 832  *
 833  * The @private argument passed here will be available to all these methods
 834  * from the file pointer, via RPC_I(file->f_dentry->d_inode)->private.
 835  */
 836 struct dentry *rpc_mkpipe_dentry(struct dentry *parent, const char *name,
 837                                  void *private, struct rpc_pipe *pipe)
 838 {
 839         struct dentry *dentry;
 840         struct inode *dir = parent->d_inode;
 841         umode_t umode = S_IFIFO | S_IRUSR | S_IWUSR;
 842         struct qstr q;
 843         int err;
 844
 845         if (pipe->ops->upcall == NULL)
 846                 umode &= ~S_IRUGO;
 847         if (pipe->ops->downcall == NULL)
 848                 umode &= ~S_IWUGO;
 849
 850         q.name = name;
 851         q.len = strlen(name);
 852         q.hash = full_name_hash(q.name, q.len),
 853
 854         mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
 855         dentry = __rpc_lookup_create_exclusive(parent, &q);
 856         if (IS_ERR(dentry))
 857                 goto out;
 858         err = __rpc_mkpipe_dentry(dir, dentry, umode, &rpc_pipe_fops,
 859                                   private, pipe);
 860         if (err)
 861                 goto out_err;
 862 out:
 863         mutex_unlock(&dir->i_mutex);
 864         return dentry;
 865 out_err:
 866         dentry = ERR_PTR(err);
 867         printk(KERN_WARNING "%s: %s() failed to create pipe %s/%s (errno = %d)\n",
 868                         __FILE__, __func__, parent->d_name.name, name,
 869                         err);
 870         goto out;
 871 }
 872 EXPORT_SYMBOL_GPL(rpc_mkpipe_dentry);
 873
 874 /**
 875  * rpc_unlink - remove a pipe
 876  * @dentry: dentry for the pipe, as returned from rpc_mkpipe
 877  *
 878  * After this call, lookups will no longer find the pipe, and any
 879  * attempts to read or write using preexisting opens of the pipe will
 880  * return -EPIPE.
 881  */
 882 int
 883 rpc_unlink(struct dentry *dentry)
 884 {
 885         struct dentry *parent;
 886         struct inode *dir;
 887         int error = 0;
 888
 889         parent = dget_parent(dentry);
 890         dir = parent->d_inode;
 891         mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
 892         error = __rpc_rmpipe(dir, dentry);
 893         mutex_unlock(&dir->i_mutex);
 894         dput(parent);
 895         return error;
 896 }
 897 EXPORT_SYMBOL_GPL(rpc_unlink);
 898
 899 enum {
 900         RPCAUTH_info,
 901         RPCAUTH_EOF
 902 };
 903
 904 static const struct rpc_filelist authfiles[] = {
 905         [RPCAUTH_info] = {
 906                 .name = "info",
 907                 .i_fop = &rpc_info_operations,
 908                 .mode = S_IFREG | S_IRUSR,
 909         },
 910 };
 911
 912 static int rpc_clntdir_populate(struct dentry *dentry, void *private)
 913 {
 914         return rpc_populate(dentry,
 915                             authfiles, RPCAUTH_info, RPCAUTH_EOF,
 916                             private);
 917 }
 918
 919 static void rpc_clntdir_depopulate(struct dentry *dentry)
 920 {
 921         rpc_depopulate(dentry, authfiles, RPCAUTH_info, RPCAUTH_EOF);
 922 }
 923
 924 /**
 925  * rpc_create_client_dir - Create a new rpc_client directory in rpc_pipefs
 926  * @dentry: dentry from the rpc_pipefs root to the new directory
 927  * @name: &struct qstr for the name
 928  * @rpc_client: rpc client to associate with this directory
 929  *
 930  * This creates a directory at the given @path associated with
 931  * @rpc_clnt, which will contain a file named "info" with some basic
 932  * information about the client, together with any "pipes" that may
 933  * later be created using rpc_mkpipe().
 934  */
 935 struct dentry *rpc_create_client_dir(struct dentry *dentry,
 936                                    struct qstr *name,
 937                                    struct rpc_clnt *rpc_client)
 938 {
 939         return rpc_mkdir_populate(dentry, name, S_IRUGO | S_IXUGO, NULL,
 940                         rpc_clntdir_populate, rpc_client);
 941 }
 942
 943 /**
 944  * rpc_remove_client_dir - Remove a directory created with rpc_create_client_dir()
 945  * @clnt: rpc client
 946  */
 947 int rpc_remove_client_dir(struct dentry *dentry)
 948 {
 949         return rpc_rmdir_depopulate(dentry, rpc_clntdir_depopulate);
 950 }
 951
 952 static const struct rpc_filelist cache_pipefs_files[3] = {
 953         [0] = {
 954                 .name = "channel",
 955                 .i_fop = &cache_file_operations_pipefs,
 956                 .mode = S_IFREG|S_IRUSR|S_IWUSR,
 957         },
 958         [1] = {
 959                 .name = "content",
 960                 .i_fop = &content_file_operations_pipefs,
 961                 .mode = S_IFREG|S_IRUSR,
 962         },
 963         [2] = {
 964                 .name = "flush",
 965                 .i_fop = &cache_flush_operations_pipefs,
 966                 .mode = S_IFREG|S_IRUSR|S_IWUSR,
 967         },
 968 };
 969
 970 static int rpc_cachedir_populate(struct dentry *dentry, void *private)
 971 {
 972         return rpc_populate(dentry,
 973                             cache_pipefs_files, 0, 3,
 974                             private);
 975 }
 976
 977 static void rpc_cachedir_depopulate(struct dentry *dentry)
 978 {
 979         rpc_depopulate(dentry, cache_pipefs_files, 0, 3);
 980 }
 981
 982 struct dentry *rpc_create_cache_dir(struct dentry *parent, struct qstr *name,
 983                                     umode_t umode, struct cache_detail *cd)
 984 {
 985         return rpc_mkdir_populate(parent, name, umode, NULL,
 986                         rpc_cachedir_populate, cd);
 987 }
 988
 989 void rpc_remove_cache_dir(struct dentry *dentry)
 990 {
 991         rpc_rmdir_depopulate(dentry, rpc_cachedir_depopulate);
 992 }
 993
 994 /*
 995  * populate the filesystem
 996  */
 997 static const struct super_operations s_ops = {
 998         .alloc_inode    = rpc_alloc_inode,
 999         .destroy_inode  = rpc_destroy_inode,
1000         .statfs         = simple_statfs,
1001 };
1002
1003 #define RPCAUTH_GSSMAGIC 0x67596969
1004
1005 /*
1006  * We have a single directory with 1 node in it.
1007  */
1008 enum {
1009         RPCAUTH_lockd,
1010         RPCAUTH_mount,
1011         RPCAUTH_nfs,
1012         RPCAUTH_portmap,
1013         RPCAUTH_statd,
1014         RPCAUTH_nfsd4_cb,
1015         RPCAUTH_cache,
1016         RPCAUTH_RootEOF
1017 };
1018
1019 static const struct rpc_filelist files[] = {
1020         [RPCAUTH_lockd] = {
1021                 .name = "lockd",
1022                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
1023         },
1024         [RPCAUTH_mount] = {
1025                 .name = "mount",
1026                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
1027         },
1028         [RPCAUTH_nfs] = {
1029                 .name = "nfs",
1030                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
1031         },
1032         [RPCAUTH_portmap] = {
1033                 .name = "portmap",
1034                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
1035         },
1036         [RPCAUTH_statd] = {
1037                 .name = "statd",
1038                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
1039         },
1040         [RPCAUTH_nfsd4_cb] = {
1041                 .name = "nfsd4_cb",
1042                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
1043         },
1044         [RPCAUTH_cache] = {
1045                 .name = "cache",
1046                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
1047         },
1048 };
1049
1050 /*
1051  * This call can be used only in RPC pipefs mount notification hooks.
1052  */
1053 struct dentry *rpc_d_lookup_sb(const struct super_block *sb,
1054                                const unsigned char *dir_name)
1055 {
1056         struct qstr dir = {
1057                 .name = dir_name,
1058                 .len = strlen(dir_name),
1059                 .hash = full_name_hash(dir_name, strlen(dir_name)),
1060         };
1061
1062         return d_lookup(sb->s_root, &dir);
1063 }
1064 EXPORT_SYMBOL_GPL(rpc_d_lookup_sb);
1065
1066 void rpc_pipefs_init_net(struct net *net)
1067 {
1068         struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
1069
1070         mutex_init(&sn->pipefs_sb_lock);
1071 }
1072
1073 /*
1074  * This call will be used for per network namespace operations calls.
1075  * Note: Function will be returned with pipefs_sb_lock taken if superblock was
1076  * found. This lock have to be released by rpc_put_sb_net() when all operations
1077  * will be completed.
1078  */
1079 struct super_block *rpc_get_sb_net(const struct net *net)
1080 {
1081         struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
1082
1083         mutex_lock(&sn->pipefs_sb_lock);
1084         if (sn->pipefs_sb)
1085                 return sn->pipefs_sb;
1086         mutex_unlock(&sn->pipefs_sb_lock);
1087         return NULL;
1088 }
1089 EXPORT_SYMBOL_GPL(rpc_get_sb_net);
1090
1091 void rpc_put_sb_net(const struct net *net)
1092 {
1093         struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
1094
1095         BUG_ON(sn->pipefs_sb == NULL);
1096         mutex_unlock(&sn->pipefs_sb_lock);
1097 }
1098 EXPORT_SYMBOL_GPL(rpc_put_sb_net);
1099
1100 static int
1101 rpc_fill_super(struct super_block *sb, void *data, int silent)
1102 {
1103         struct inode *inode;
1104         struct dentry *root;
1105         struct net *net = data;
1106         struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
1107         int err;
1108
1109         sb->s_blocksize = PAGE_CACHE_SIZE;
1110         sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
1111         sb->s_magic = RPCAUTH_GSSMAGIC;
1112         sb->s_op = &s_ops;
1113         sb->s_time_gran = 1;
1114
1115         inode = rpc_get_inode(sb, S_IFDIR | 0755);
1116         if (!inode)
1117                 return -ENOMEM;
1118         sb->s_root = root = d_alloc_root(inode);
1119         if (!root) {
1120                 iput(inode);
1121                 return -ENOMEM;
1122         }
1123         if (rpc_populate(root, files, RPCAUTH_lockd, RPCAUTH_RootEOF, NULL))
1124                 return -ENOMEM;
1125         dprintk("RPC:   sending pipefs MOUNT notification for net %p%s\n", net,
1126                                                                 NET_NAME(net));
1127         err = blocking_notifier_call_chain(&rpc_pipefs_notifier_list,
1128                                            RPC_PIPEFS_MOUNT,
1129                                            sb);
1130         if (err)
1131                 goto err_depopulate;
1132         sb->s_fs_info = get_net(net);
1133         sn->pipefs_sb = sb;
1134         return 0;
1135
1136 err_depopulate:
1137         blocking_notifier_call_chain(&rpc_pipefs_notifier_list,
1138                                            RPC_PIPEFS_UMOUNT,
1139                                            sb);
1140         __rpc_depopulate(root, files, RPCAUTH_lockd, RPCAUTH_RootEOF);
1141         return err;
1142 }
1143
1144 static struct dentry *
1145 rpc_mount(struct file_system_type *fs_type,
1146                 int flags, const char *dev_name, void *data)
1147 {
1148         return mount_ns(fs_type, flags, current->nsproxy->net_ns, rpc_fill_super);
1149 }
1150
1151 void rpc_kill_sb(struct super_block *sb)
1152 {
1153         struct net *net = sb->s_fs_info;
1154         struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
1155
1156         mutex_lock(&sn->pipefs_sb_lock);
1157         sn->pipefs_sb = NULL;
1158         mutex_unlock(&sn->pipefs_sb_lock);
1159         put_net(net);
1160         dprintk("RPC:   sending pipefs UMOUNT notification for net %p%s\n", net,
1161                                                                 NET_NAME(net));
1162         blocking_notifier_call_chain(&rpc_pipefs_notifier_list,
1163                                            RPC_PIPEFS_UMOUNT,
1164                                            sb);
1165         kill_litter_super(sb);
1166 }
1167
1168 static struct file_system_type rpc_pipe_fs_type = {
1169         .owner          = THIS_MODULE,
1170         .name           = "rpc_pipefs",
1171         .mount          = rpc_mount,
1172         .kill_sb        = rpc_kill_sb,
1173 };
1174
1175 static void
1176 init_once(void *foo)
1177 {
1178         struct rpc_inode *rpci = (struct rpc_inode *) foo;
1179
1180         inode_init_once(&rpci->vfs_inode);
1181         rpci->private = NULL;
1182         rpci->pipe = NULL;
1183         init_waitqueue_head(&rpci->waitq);
1184 }
1185
1186 int register_rpc_pipefs(void)
1187 {
1188         int err;
1189
1190         rpc_inode_cachep = kmem_cache_create("rpc_inode_cache",
1191                                 sizeof(struct rpc_inode),
1192                                 0, (SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT|
1193                                                 SLAB_MEM_SPREAD),
1194                                 init_once);
1195         if (!rpc_inode_cachep)
1196                 return -ENOMEM;
1197         err = rpc_clients_notifier_register();
1198         if (err)
1199                 goto err_notifier;
1200         err = register_filesystem(&rpc_pipe_fs_type);
1201         if (err)
1202                 goto err_register;
1203         return 0;
1204
1205 err_register:
1206         rpc_clients_notifier_unregister();
1207 err_notifier:
1208         kmem_cache_destroy(rpc_inode_cachep);
1209         return err;
1210 }
1211
1212 void unregister_rpc_pipefs(void)
1213 {
1214         rpc_clients_notifier_unregister();
1215         kmem_cache_destroy(rpc_inode_cachep);
1216         unregister_filesystem(&rpc_pipe_fs_type);
1217 }
1218
1219 /* Make 'mount -t rpc_pipefs ...' autoload this module. */
1220 MODULE_ALIAS("rpc_pipefs");