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