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
  30 static struct vfsmount *rpc_mount __read_mostly;
  31 static int rpc_mount_count;
  32
  33 static struct file_system_type rpc_pipe_fs_type;
  34
  35
  36 static struct kmem_cache *rpc_inode_cachep __read_mostly;
  37
  38 #define RPC_UPCALL_TIMEOUT (30*HZ)
  39
  40 static void rpc_purge_list(struct rpc_inode *rpci, struct list_head *head,
  41                 void (*destroy_msg)(struct rpc_pipe_msg *), int err)
  42 {
  43         struct rpc_pipe_msg *msg;
  44
  45         if (list_empty(head))
  46                 return;
  47         do {
  48                 msg = list_entry(head->next, struct rpc_pipe_msg, list);
  49                 list_del(&msg->list);
  50                 msg->errno = err;
  51                 destroy_msg(msg);
  52         } while (!list_empty(head));
  53         wake_up(&rpci->waitq);
  54 }
  55
  56 static void
  57 rpc_timeout_upcall_queue(struct work_struct *work)
  58 {
  59         LIST_HEAD(free_list);
  60         struct rpc_inode *rpci =
  61                 container_of(work, struct rpc_inode, queue_timeout.work);
  62         struct inode *inode = &rpci->vfs_inode;
  63         void (*destroy_msg)(struct rpc_pipe_msg *);
  64
  65         spin_lock(&inode->i_lock);
  66         if (rpci->ops == NULL) {
  67                 spin_unlock(&inode->i_lock);
  68                 return;
  69         }
  70         destroy_msg = rpci->ops->destroy_msg;
  71         if (rpci->nreaders == 0) {
  72                 list_splice_init(&rpci->pipe, &free_list);
  73                 rpci->pipelen = 0;
  74         }
  75         spin_unlock(&inode->i_lock);
  76         rpc_purge_list(rpci, &free_list, destroy_msg, -ETIMEDOUT);
  77 }
  78
  79 /**
  80  * rpc_queue_upcall
  81  * @inode: inode of upcall pipe on which to queue given message
  82  * @msg: message to queue
  83  *
  84  * Call with an @inode created by rpc_mkpipe() to queue an upcall.
  85  * A userspace process may then later read the upcall by performing a
  86  * read on an open file for this inode.  It is up to the caller to
  87  * initialize the fields of @msg (other than @msg->list) appropriately.
  88  */
  89 int
  90 rpc_queue_upcall(struct inode *inode, struct rpc_pipe_msg *msg)
  91 {
  92         struct rpc_inode *rpci = RPC_I(inode);
  93         int res = -EPIPE;
  94
  95         spin_lock(&inode->i_lock);
  96         if (rpci->ops == NULL)
  97                 goto out;
  98         if (rpci->nreaders) {
  99                 list_add_tail(&msg->list, &rpci->pipe);
 100                 rpci->pipelen += msg->len;
 101                 res = 0;
 102         } else if (rpci->flags & RPC_PIPE_WAIT_FOR_OPEN) {
 103                 if (list_empty(&rpci->pipe))
 104                         queue_delayed_work(rpciod_workqueue,
 105                                         &rpci->queue_timeout,
 106                                         RPC_UPCALL_TIMEOUT);
 107                 list_add_tail(&msg->list, &rpci->pipe);
 108                 rpci->pipelen += msg->len;
 109                 res = 0;
 110         }
 111 out:
 112         spin_unlock(&inode->i_lock);
 113         wake_up(&rpci->waitq);
 114         return res;
 115 }
 116 EXPORT_SYMBOL_GPL(rpc_queue_upcall);
 117
 118 static inline void
 119 rpc_inode_setowner(struct inode *inode, void *private)
 120 {
 121         RPC_I(inode)->private = private;
 122 }
 123
 124 static void
 125 rpc_close_pipes(struct inode *inode)
 126 {
 127         struct rpc_inode *rpci = RPC_I(inode);
 128         const struct rpc_pipe_ops *ops;
 129         int need_release;
 130
 131         mutex_lock(&inode->i_mutex);
 132         ops = rpci->ops;
 133         if (ops != NULL) {
 134                 LIST_HEAD(free_list);
 135                 spin_lock(&inode->i_lock);
 136                 need_release = rpci->nreaders != 0 || rpci->nwriters != 0;
 137                 rpci->nreaders = 0;
 138                 list_splice_init(&rpci->in_upcall, &free_list);
 139                 list_splice_init(&rpci->pipe, &free_list);
 140                 rpci->pipelen = 0;
 141                 rpci->ops = NULL;
 142                 spin_unlock(&inode->i_lock);
 143                 rpc_purge_list(rpci, &free_list, ops->destroy_msg, -EPIPE);
 144                 rpci->nwriters = 0;
 145                 if (need_release && ops->release_pipe)
 146                         ops->release_pipe(inode);
 147                 cancel_delayed_work_sync(&rpci->queue_timeout);
 148         }
 149         rpc_inode_setowner(inode, NULL);
 150         mutex_unlock(&inode->i_mutex);
 151 }
 152
 153 static struct inode *
 154 rpc_alloc_inode(struct super_block *sb)
 155 {
 156         struct rpc_inode *rpci;
 157         rpci = (struct rpc_inode *)kmem_cache_alloc(rpc_inode_cachep, GFP_KERNEL);
 158         if (!rpci)
 159                 return NULL;
 160         return &rpci->vfs_inode;
 161 }
 162
 163 static void
 164 rpc_destroy_inode(struct inode *inode)
 165 {
 166         kmem_cache_free(rpc_inode_cachep, RPC_I(inode));
 167 }
 168
 169 static int
 170 rpc_pipe_open(struct inode *inode, struct file *filp)
 171 {
 172         struct rpc_inode *rpci = RPC_I(inode);
 173         int first_open;
 174         int res = -ENXIO;
 175
 176         mutex_lock(&inode->i_mutex);
 177         if (rpci->ops == NULL)
 178                 goto out;
 179         first_open = rpci->nreaders == 0 && rpci->nwriters == 0;
 180         if (first_open && rpci->ops->open_pipe) {
 181                 res = rpci->ops->open_pipe(inode);
 182                 if (res)
 183                         goto out;
 184         }
 185         if (filp->f_mode & FMODE_READ)
 186                 rpci->nreaders++;
 187         if (filp->f_mode & FMODE_WRITE)
 188                 rpci->nwriters++;
 189         res = 0;
 190 out:
 191         mutex_unlock(&inode->i_mutex);
 192         return res;
 193 }
 194
 195 static int
 196 rpc_pipe_release(struct inode *inode, struct file *filp)
 197 {
 198         struct rpc_inode *rpci = RPC_I(inode);
 199         struct rpc_pipe_msg *msg;
 200         int last_close;
 201
 202         mutex_lock(&inode->i_mutex);
 203         if (rpci->ops == NULL)
 204                 goto out;
 205         msg = (struct rpc_pipe_msg *)filp->private_data;
 206         if (msg != NULL) {
 207                 spin_lock(&inode->i_lock);
 208                 msg->errno = -EAGAIN;
 209                 list_del(&msg->list);
 210                 spin_unlock(&inode->i_lock);
 211                 rpci->ops->destroy_msg(msg);
 212         }
 213         if (filp->f_mode & FMODE_WRITE)
 214                 rpci->nwriters --;
 215         if (filp->f_mode & FMODE_READ) {
 216                 rpci->nreaders --;
 217                 if (rpci->nreaders == 0) {
 218                         LIST_HEAD(free_list);
 219                         spin_lock(&inode->i_lock);
 220                         list_splice_init(&rpci->pipe, &free_list);
 221                         rpci->pipelen = 0;
 222                         spin_unlock(&inode->i_lock);
 223                         rpc_purge_list(rpci, &free_list,
 224                                         rpci->ops->destroy_msg, -EAGAIN);
 225                 }
 226         }
 227         last_close = rpci->nwriters == 0 && rpci->nreaders == 0;
 228         if (last_close && rpci->ops->release_pipe)
 229                 rpci->ops->release_pipe(inode);
 230 out:
 231         mutex_unlock(&inode->i_mutex);
 232         return 0;
 233 }
 234
 235 static ssize_t
 236 rpc_pipe_read(struct file *filp, char __user *buf, size_t len, loff_t *offset)
 237 {
 238         struct inode *inode = filp->f_path.dentry->d_inode;
 239         struct rpc_inode *rpci = RPC_I(inode);
 240         struct rpc_pipe_msg *msg;
 241         int res = 0;
 242
 243         mutex_lock(&inode->i_mutex);
 244         if (rpci->ops == NULL) {
 245                 res = -EPIPE;
 246                 goto out_unlock;
 247         }
 248         msg = filp->private_data;
 249         if (msg == NULL) {
 250                 spin_lock(&inode->i_lock);
 251                 if (!list_empty(&rpci->pipe)) {
 252                         msg = list_entry(rpci->pipe.next,
 253                                         struct rpc_pipe_msg,
 254                                         list);
 255                         list_move(&msg->list, &rpci->in_upcall);
 256                         rpci->pipelen -= msg->len;
 257                         filp->private_data = msg;
 258                         msg->copied = 0;
 259                 }
 260                 spin_unlock(&inode->i_lock);
 261                 if (msg == NULL)
 262                         goto out_unlock;
 263         }
 264         /* NOTE: it is up to the callback to update msg->copied */
 265         res = rpci->ops->upcall(filp, msg, buf, len);
 266         if (res < 0 || msg->len == msg->copied) {
 267                 filp->private_data = NULL;
 268                 spin_lock(&inode->i_lock);
 269                 list_del(&msg->list);
 270                 spin_unlock(&inode->i_lock);
 271                 rpci->ops->destroy_msg(msg);
 272         }
 273 out_unlock:
 274         mutex_unlock(&inode->i_mutex);
 275         return res;
 276 }
 277
 278 static ssize_t
 279 rpc_pipe_write(struct file *filp, const char __user *buf, size_t len, loff_t *offset)
 280 {
 281         struct inode *inode = filp->f_path.dentry->d_inode;
 282         struct rpc_inode *rpci = RPC_I(inode);
 283         int res;
 284
 285         mutex_lock(&inode->i_mutex);
 286         res = -EPIPE;
 287         if (rpci->ops != NULL)
 288                 res = rpci->ops->downcall(filp, buf, len);
 289         mutex_unlock(&inode->i_mutex);
 290         return res;
 291 }
 292
 293 static unsigned int
 294 rpc_pipe_poll(struct file *filp, struct poll_table_struct *wait)
 295 {
 296         struct rpc_inode *rpci;
 297         unsigned int mask = 0;
 298
 299         rpci = RPC_I(filp->f_path.dentry->d_inode);
 300         poll_wait(filp, &rpci->waitq, wait);
 301
 302         mask = POLLOUT | POLLWRNORM;
 303         if (rpci->ops == NULL)
 304                 mask |= POLLERR | POLLHUP;
 305         if (filp->private_data || !list_empty(&rpci->pipe))
 306                 mask |= POLLIN | POLLRDNORM;
 307         return mask;
 308 }
 309
 310 static int
 311 rpc_pipe_ioctl(struct inode *ino, struct file *filp,
 312                 unsigned int cmd, unsigned long arg)
 313 {
 314         struct rpc_inode *rpci = RPC_I(filp->f_path.dentry->d_inode);
 315         int len;
 316
 317         switch (cmd) {
 318         case FIONREAD:
 319                 if (rpci->ops == NULL)
 320                         return -EPIPE;
 321                 len = rpci->pipelen;
 322                 if (filp->private_data) {
 323                         struct rpc_pipe_msg *msg;
 324                         msg = (struct rpc_pipe_msg *)filp->private_data;
 325                         len += msg->len - msg->copied;
 326                 }
 327                 return put_user(len, (int __user *)arg);
 328         default:
 329                 return -EINVAL;
 330         }
 331 }
 332
 333 static const struct file_operations rpc_pipe_fops = {
 334         .owner          = THIS_MODULE,
 335         .llseek         = no_llseek,
 336         .read           = rpc_pipe_read,
 337         .write          = rpc_pipe_write,
 338         .poll           = rpc_pipe_poll,
 339         .ioctl          = rpc_pipe_ioctl,
 340         .open           = rpc_pipe_open,
 341         .release        = rpc_pipe_release,
 342 };
 343
 344 static int
 345 rpc_show_info(struct seq_file *m, void *v)
 346 {
 347         struct rpc_clnt *clnt = m->private;
 348
 349         seq_printf(m, "RPC server: %s\n", clnt->cl_server);
 350         seq_printf(m, "service: %s (%d) version %d\n", clnt->cl_protname,
 351                         clnt->cl_prog, clnt->cl_vers);
 352         seq_printf(m, "address: %s\n", rpc_peeraddr2str(clnt, RPC_DISPLAY_ADDR));
 353         seq_printf(m, "protocol: %s\n", rpc_peeraddr2str(clnt, RPC_DISPLAY_PROTO));
 354         seq_printf(m, "port: %s\n", rpc_peeraddr2str(clnt, RPC_DISPLAY_PORT));
 355         return 0;
 356 }
 357
 358 static int
 359 rpc_info_open(struct inode *inode, struct file *file)
 360 {
 361         struct rpc_clnt *clnt;
 362         int ret = single_open(file, rpc_show_info, NULL);
 363
 364         if (!ret) {
 365                 struct seq_file *m = file->private_data;
 366                 mutex_lock(&inode->i_mutex);
 367                 clnt = RPC_I(inode)->private;
 368                 if (clnt) {
 369                         kref_get(&clnt->cl_kref);
 370                         m->private = clnt;
 371                 } else {
 372                         single_release(inode, file);
 373                         ret = -EINVAL;
 374                 }
 375                 mutex_unlock(&inode->i_mutex);
 376         }
 377         return ret;
 378 }
 379
 380 static int
 381 rpc_info_release(struct inode *inode, struct file *file)
 382 {
 383         struct seq_file *m = file->private_data;
 384         struct rpc_clnt *clnt = (struct rpc_clnt *)m->private;
 385
 386         if (clnt)
 387                 rpc_release_client(clnt);
 388         return single_release(inode, file);
 389 }
 390
 391 static const struct file_operations rpc_info_operations = {
 392         .owner          = THIS_MODULE,
 393         .open           = rpc_info_open,
 394         .read           = seq_read,
 395         .llseek         = seq_lseek,
 396         .release        = rpc_info_release,
 397 };
 398
 399
 400 /*
 401  * Description of fs contents.
 402  */
 403 struct rpc_filelist {
 404         const char *name;
 405         const struct file_operations *i_fop;
 406         umode_t mode;
 407 };
 408
 409 enum {
 410         RPCAUTH_info,
 411         RPCAUTH_EOF
 412 };
 413
 414 static const struct rpc_filelist authfiles[] = {
 415         [RPCAUTH_info] = {
 416                 .name = "info",
 417                 .i_fop = &rpc_info_operations,
 418                 .mode = S_IFREG | S_IRUSR,
 419         },
 420 };
 421
 422 struct vfsmount *rpc_get_mount(void)
 423 {
 424         int err;
 425
 426         err = simple_pin_fs(&rpc_pipe_fs_type, &rpc_mount, &rpc_mount_count);
 427         if (err != 0)
 428                 return ERR_PTR(err);
 429         return rpc_mount;
 430 }
 431
 432 void rpc_put_mount(void)
 433 {
 434         simple_release_fs(&rpc_mount, &rpc_mount_count);
 435 }
 436
 437 static int rpc_delete_dentry(struct dentry *dentry)
 438 {
 439         return 1;
 440 }
 441
 442 static const struct dentry_operations rpc_dentry_operations = {
 443         .d_delete = rpc_delete_dentry,
 444 };
 445
 446 static struct inode *
 447 rpc_get_inode(struct super_block *sb, umode_t mode)
 448 {
 449         struct inode *inode = new_inode(sb);
 450         if (!inode)
 451                 return NULL;
 452         inode->i_mode = mode;
 453         inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
 454         switch(mode & S_IFMT) {
 455                 case S_IFDIR:
 456                         inode->i_fop = &simple_dir_operations;
 457                         inode->i_op = &simple_dir_inode_operations;
 458                         inc_nlink(inode);
 459                 default:
 460                         break;
 461         }
 462         return inode;
 463 }
 464
 465 static int __rpc_create_common(struct inode *dir, struct dentry *dentry,
 466                                umode_t mode,
 467                                const struct file_operations *i_fop,
 468                                void *private)
 469 {
 470         struct inode *inode;
 471
 472         BUG_ON(!d_unhashed(dentry));
 473         inode = rpc_get_inode(dir->i_sb, mode);
 474         if (!inode)
 475                 goto out_err;
 476         inode->i_ino = iunique(dir->i_sb, 100);
 477         if (i_fop)
 478                 inode->i_fop = i_fop;
 479         if (private)
 480                 rpc_inode_setowner(inode, private);
 481         d_add(dentry, inode);
 482         return 0;
 483 out_err:
 484         printk(KERN_WARNING "%s: %s failed to allocate inode for dentry %s\n",
 485                         __FILE__, __func__, dentry->d_name.name);
 486         dput(dentry);
 487         return -ENOMEM;
 488 }
 489
 490 static int __rpc_create(struct inode *dir, struct dentry *dentry,
 491                         umode_t mode,
 492                         const struct file_operations *i_fop,
 493                         void *private)
 494 {
 495         int err;
 496
 497         err = __rpc_create_common(dir, dentry, S_IFREG | mode, i_fop, private);
 498         if (err)
 499                 return err;
 500         fsnotify_create(dir, dentry);
 501         return 0;
 502 }
 503
 504 static int __rpc_mkdir(struct inode *dir, struct dentry *dentry,
 505                        umode_t mode,
 506                        const struct file_operations *i_fop,
 507                        void *private)
 508 {
 509         int err;
 510
 511         err = __rpc_create_common(dir, dentry, S_IFDIR | mode, i_fop, private);
 512         if (err)
 513                 return err;
 514         inc_nlink(dir);
 515         fsnotify_mkdir(dir, dentry);
 516         return 0;
 517 }
 518
 519 static int __rpc_mkpipe(struct inode *dir, struct dentry *dentry,
 520                         umode_t mode,
 521                         const struct file_operations *i_fop,
 522                         void *private,
 523                         const struct rpc_pipe_ops *ops,
 524                         int flags)
 525 {
 526         struct rpc_inode *rpci;
 527         int err;
 528
 529         err = __rpc_create_common(dir, dentry, S_IFIFO | mode, i_fop, private);
 530         if (err)
 531                 return err;
 532         rpci = RPC_I(dentry->d_inode);
 533         rpci->nkern_readwriters = 1;
 534         rpci->private = private;
 535         rpci->flags = flags;
 536         rpci->ops = ops;
 537         fsnotify_create(dir, dentry);
 538         return 0;
 539 }
 540
 541 static int __rpc_rmdir(struct inode *dir, struct dentry *dentry)
 542 {
 543         int ret;
 544
 545         dget(dentry);
 546         ret = simple_rmdir(dir, dentry);
 547         d_delete(dentry);
 548         dput(dentry);
 549         return ret;
 550 }
 551
 552 static int __rpc_unlink(struct inode *dir, struct dentry *dentry)
 553 {
 554         int ret;
 555
 556         dget(dentry);
 557         ret = simple_unlink(dir, dentry);
 558         d_delete(dentry);
 559         dput(dentry);
 560         return ret;
 561 }
 562
 563 static int __rpc_rmpipe(struct inode *dir, struct dentry *dentry)
 564 {
 565         struct inode *inode = dentry->d_inode;
 566         struct rpc_inode *rpci = RPC_I(inode);
 567
 568         rpci->nkern_readwriters--;
 569         if (rpci->nkern_readwriters != 0)
 570                 return 0;
 571         rpc_close_pipes(inode);
 572         return __rpc_unlink(dir, dentry);
 573 }
 574
 575 static struct dentry *__rpc_lookup_create(struct dentry *parent,
 576                                           struct qstr *name)
 577 {
 578         struct dentry *dentry;
 579
 580         dentry = d_lookup(parent, name);
 581         if (!dentry) {
 582                 dentry = d_alloc(parent, name);
 583                 if (!dentry) {
 584                         dentry = ERR_PTR(-ENOMEM);
 585                         goto out_err;
 586                 }
 587         }
 588         if (!dentry->d_inode)
 589                 dentry->d_op = &rpc_dentry_operations;
 590 out_err:
 591         return dentry;
 592 }
 593
 594 static struct dentry *__rpc_lookup_create_exclusive(struct dentry *parent,
 595                                           struct qstr *name)
 596 {
 597         struct dentry *dentry;
 598
 599         dentry = __rpc_lookup_create(parent, name);
 600         if (dentry->d_inode == NULL)
 601                 return dentry;
 602         dput(dentry);
 603         return ERR_PTR(-EEXIST);
 604 }
 605
 606 /*
 607  * FIXME: This probably has races.
 608  */
 609 static void __rpc_depopulate(struct dentry *parent,
 610                              const struct rpc_filelist *files,
 611                              int start, int eof)
 612 {
 613         struct inode *dir = parent->d_inode;
 614         struct dentry *dentry;
 615         struct qstr name;
 616         int i;
 617
 618         for (i = start; i < eof; i++) {
 619                 name.name = files[i].name;
 620                 name.len = strlen(files[i].name);
 621                 name.hash = full_name_hash(name.name, name.len);
 622                 dentry = d_lookup(parent, &name);
 623
 624                 if (dentry == NULL)
 625                         continue;
 626                 if (dentry->d_inode == NULL)
 627                         goto next;
 628                 switch (dentry->d_inode->i_mode & S_IFMT) {
 629                         default:
 630                                 BUG();
 631                         case S_IFREG:
 632                                 __rpc_unlink(dir, dentry);
 633                                 break;
 634                         case S_IFDIR:
 635                                 __rpc_rmdir(dir, dentry);
 636                 }
 637 next:
 638                 dput(dentry);
 639         }
 640 }
 641
 642 static void rpc_depopulate(struct dentry *parent,
 643                            const struct rpc_filelist *files,
 644                            int start, int eof)
 645 {
 646         struct inode *dir = parent->d_inode;
 647
 648         mutex_lock_nested(&dir->i_mutex, I_MUTEX_CHILD);
 649         __rpc_depopulate(parent, files, start, eof);
 650         mutex_unlock(&dir->i_mutex);
 651 }
 652
 653 static int rpc_populate(struct dentry *parent,
 654                         const struct rpc_filelist *files,
 655                         int start, int eof,
 656                         void *private)
 657 {
 658         struct inode *dir = parent->d_inode;
 659         struct dentry *dentry;
 660         int i, err;
 661
 662         mutex_lock(&dir->i_mutex);
 663         for (i = start; i < eof; i++) {
 664                 struct qstr q;
 665
 666                 q.name = files[i].name;
 667                 q.len = strlen(files[i].name);
 668                 q.hash = full_name_hash(q.name, q.len);
 669                 dentry = __rpc_lookup_create_exclusive(parent, &q);
 670                 err = PTR_ERR(dentry);
 671                 if (IS_ERR(dentry))
 672                         goto out_bad;
 673                 switch (files[i].mode & S_IFMT) {
 674                         default:
 675                                 BUG();
 676                         case S_IFREG:
 677                                 err = __rpc_create(dir, dentry,
 678                                                 files[i].mode,
 679                                                 files[i].i_fop,
 680                                                 private);
 681                                 break;
 682                         case S_IFDIR:
 683                                 err = __rpc_mkdir(dir, dentry,
 684                                                 files[i].mode,
 685                                                 NULL,
 686                                                 private);
 687                 }
 688                 if (err != 0)
 689                         goto out_bad;
 690         }
 691         mutex_unlock(&dir->i_mutex);
 692         return 0;
 693 out_bad:
 694         __rpc_depopulate(parent, files, start, eof);
 695         mutex_unlock(&dir->i_mutex);
 696         printk(KERN_WARNING "%s: %s failed to populate directory %s\n",
 697                         __FILE__, __func__, parent->d_name.name);
 698         return err;
 699 }
 700
 701 struct dentry *rpc_mkdir_populate(struct dentry *parent,
 702                 struct qstr *name, umode_t mode, void *private)
 703 {
 704         struct dentry *dentry;
 705         struct inode *dir = parent->d_inode;
 706         int error;
 707
 708         mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
 709         dentry = __rpc_lookup_create_exclusive(parent, name);
 710         if (IS_ERR(dentry))
 711                 goto out;
 712         error = __rpc_mkdir(dir, dentry, mode, NULL, private);
 713         if (error != 0)
 714                 goto out_err;
 715         error = rpc_populate(dentry, authfiles,
 716                         RPCAUTH_info, RPCAUTH_EOF, private);
 717         if (error)
 718                 goto err_rmdir;
 719 out:
 720         mutex_unlock(&dir->i_mutex);
 721         return dentry;
 722 err_rmdir:
 723         __rpc_rmdir(dir, dentry);
 724 out_err:
 725         dentry = ERR_PTR(error);
 726         goto out;
 727 }
 728
 729 /**
 730  * rpc_remove_client_dir - Remove a directory created with rpc_create_client_dir()
 731  * @dentry: directory to remove
 732  */
 733 int rpc_remove_client_dir(struct dentry *dentry)
 734 {
 735         struct dentry *parent;
 736         struct inode *dir;
 737         int error;
 738
 739         parent = dget_parent(dentry);
 740         dir = parent->d_inode;
 741         mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
 742         rpc_depopulate(dentry, authfiles, RPCAUTH_info, RPCAUTH_EOF);
 743         error = __rpc_rmdir(dir, dentry);
 744         mutex_unlock(&dir->i_mutex);
 745         dput(parent);
 746         return error;
 747 }
 748
 749 /**
 750  * rpc_mkpipe - make an rpc_pipefs file for kernel<->userspace communication
 751  * @parent: dentry of directory to create new "pipe" in
 752  * @name: name of pipe
 753  * @private: private data to associate with the pipe, for the caller's use
 754  * @ops: operations defining the behavior of the pipe: upcall, downcall,
 755  *      release_pipe, open_pipe, and destroy_msg.
 756  * @flags: rpc_inode flags
 757  *
 758  * Data is made available for userspace to read by calls to
 759  * rpc_queue_upcall().  The actual reads will result in calls to
 760  * @ops->upcall, which will be called with the file pointer,
 761  * message, and userspace buffer to copy to.
 762  *
 763  * Writes can come at any time, and do not necessarily have to be
 764  * responses to upcalls.  They will result in calls to @msg->downcall.
 765  *
 766  * The @private argument passed here will be available to all these methods
 767  * from the file pointer, via RPC_I(file->f_dentry->d_inode)->private.
 768  */
 769 struct dentry *rpc_mkpipe(struct dentry *parent, const char *name,
 770                           void *private, const struct rpc_pipe_ops *ops,
 771                           int flags)
 772 {
 773         struct dentry *dentry;
 774         struct inode *dir = parent->d_inode;
 775         umode_t umode = S_IFIFO | S_IRUSR | S_IWUSR;
 776         struct qstr q;
 777         int err;
 778
 779         if (ops->upcall == NULL)
 780                 umode &= ~S_IRUGO;
 781         if (ops->downcall == NULL)
 782                 umode &= ~S_IWUGO;
 783
 784         q.name = name;
 785         q.len = strlen(name);
 786         q.hash = full_name_hash(q.name, q.len),
 787
 788         mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
 789         dentry = __rpc_lookup_create(parent, &q);
 790         if (IS_ERR(dentry))
 791                 goto out;
 792         if (dentry->d_inode) {
 793                 struct rpc_inode *rpci = RPC_I(dentry->d_inode);
 794                 if (rpci->private != private ||
 795                                 rpci->ops != ops ||
 796                                 rpci->flags != flags) {
 797                         dput (dentry);
 798                         err = -EBUSY;
 799                         goto out_err;
 800                 }
 801                 rpci->nkern_readwriters++;
 802                 goto out;
 803         }
 804
 805         err = __rpc_mkpipe(dir, dentry, umode, &rpc_pipe_fops,
 806                            private, ops, flags);
 807         if (err)
 808                 goto out_err;
 809 out:
 810         mutex_unlock(&dir->i_mutex);
 811         return dentry;
 812 out_err:
 813         dentry = ERR_PTR(err);
 814         printk(KERN_WARNING "%s: %s() failed to create pipe %s/%s (errno = %d)\n",
 815                         __FILE__, __func__, parent->d_name.name, name,
 816                         err);
 817         goto out;
 818 }
 819 EXPORT_SYMBOL_GPL(rpc_mkpipe);
 820
 821 /**
 822  * rpc_unlink - remove a pipe
 823  * @dentry: dentry for the pipe, as returned from rpc_mkpipe
 824  *
 825  * After this call, lookups will no longer find the pipe, and any
 826  * attempts to read or write using preexisting opens of the pipe will
 827  * return -EPIPE.
 828  */
 829 int
 830 rpc_unlink(struct dentry *dentry)
 831 {
 832         struct dentry *parent;
 833         struct inode *dir;
 834         int error = 0;
 835
 836         parent = dget_parent(dentry);
 837         dir = parent->d_inode;
 838         mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
 839         error = __rpc_rmpipe(dir, dentry);
 840         mutex_unlock(&dir->i_mutex);
 841         dput(parent);
 842         return error;
 843 }
 844 EXPORT_SYMBOL_GPL(rpc_unlink);
 845
 846 /**
 847  * rpc_create_client_dir - Create a new rpc_client directory in rpc_pipefs
 848  * @path: path from the rpc_pipefs root to the new directory
 849  * @rpc_client: rpc client to associate with this directory
 850  *
 851  * This creates a directory at the given @path associated with
 852  * @rpc_clnt, which will contain a file named "info" with some basic
 853  * information about the client, together with any "pipes" that may
 854  * later be created using rpc_mkpipe().
 855  */
 856 struct dentry *rpc_create_client_dir(struct dentry *dentry,
 857                                      struct qstr *name,
 858                                      struct rpc_clnt *rpc_client)
 859 {
 860         return rpc_mkdir_populate(dentry, name, S_IRUGO | S_IXUGO, rpc_client);
 861 }
 862
 863 /*
 864  * populate the filesystem
 865  */
 866 static struct super_operations s_ops = {
 867         .alloc_inode    = rpc_alloc_inode,
 868         .destroy_inode  = rpc_destroy_inode,
 869         .statfs         = simple_statfs,
 870 };
 871
 872 #define RPCAUTH_GSSMAGIC 0x67596969
 873
 874 /*
 875  * We have a single directory with 1 node in it.
 876  */
 877 enum {
 878         RPCAUTH_lockd,
 879         RPCAUTH_mount,
 880         RPCAUTH_nfs,
 881         RPCAUTH_portmap,
 882         RPCAUTH_statd,
 883         RPCAUTH_nfsd4_cb,
 884         RPCAUTH_RootEOF
 885 };
 886
 887 static const struct rpc_filelist files[] = {
 888         [RPCAUTH_lockd] = {
 889                 .name = "lockd",
 890                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
 891         },
 892         [RPCAUTH_mount] = {
 893                 .name = "mount",
 894                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
 895         },
 896         [RPCAUTH_nfs] = {
 897                 .name = "nfs",
 898                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
 899         },
 900         [RPCAUTH_portmap] = {
 901                 .name = "portmap",
 902                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
 903         },
 904         [RPCAUTH_statd] = {
 905                 .name = "statd",
 906                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
 907         },
 908         [RPCAUTH_nfsd4_cb] = {
 909                 .name = "nfsd4_cb",
 910                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
 911         },
 912 };
 913
 914 static int
 915 rpc_fill_super(struct super_block *sb, void *data, int silent)
 916 {
 917         struct inode *inode;
 918         struct dentry *root;
 919
 920         sb->s_blocksize = PAGE_CACHE_SIZE;
 921         sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
 922         sb->s_magic = RPCAUTH_GSSMAGIC;
 923         sb->s_op = &s_ops;
 924         sb->s_time_gran = 1;
 925
 926         inode = rpc_get_inode(sb, S_IFDIR | 0755);
 927         if (!inode)
 928                 return -ENOMEM;
 929         root = d_alloc_root(inode);
 930         if (!root) {
 931                 iput(inode);
 932                 return -ENOMEM;
 933         }
 934         if (rpc_populate(root, files, RPCAUTH_lockd, RPCAUTH_RootEOF, NULL))
 935                 goto out;
 936         sb->s_root = root;
 937         return 0;
 938 out:
 939         d_genocide(root);
 940         dput(root);
 941         return -ENOMEM;
 942 }
 943
 944 static int
 945 rpc_get_sb(struct file_system_type *fs_type,
 946                 int flags, const char *dev_name, void *data, struct vfsmount *mnt)
 947 {
 948         return get_sb_single(fs_type, flags, data, rpc_fill_super, mnt);
 949 }
 950
 951 static struct file_system_type rpc_pipe_fs_type = {
 952         .owner          = THIS_MODULE,
 953         .name           = "rpc_pipefs",
 954         .get_sb         = rpc_get_sb,
 955         .kill_sb        = kill_litter_super,
 956 };
 957
 958 static void
 959 init_once(void *foo)
 960 {
 961         struct rpc_inode *rpci = (struct rpc_inode *) foo;
 962
 963         inode_init_once(&rpci->vfs_inode);
 964         rpci->private = NULL;
 965         rpci->nreaders = 0;
 966         rpci->nwriters = 0;
 967         INIT_LIST_HEAD(&rpci->in_upcall);
 968         INIT_LIST_HEAD(&rpci->in_downcall);
 969         INIT_LIST_HEAD(&rpci->pipe);
 970         rpci->pipelen = 0;
 971         init_waitqueue_head(&rpci->waitq);
 972         INIT_DELAYED_WORK(&rpci->queue_timeout,
 973                             rpc_timeout_upcall_queue);
 974         rpci->ops = NULL;
 975 }
 976
 977 int register_rpc_pipefs(void)
 978 {
 979         int err;
 980
 981         rpc_inode_cachep = kmem_cache_create("rpc_inode_cache",
 982                                 sizeof(struct rpc_inode),
 983                                 0, (SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT|
 984                                                 SLAB_MEM_SPREAD),
 985                                 init_once);
 986         if (!rpc_inode_cachep)
 987                 return -ENOMEM;
 988         err = register_filesystem(&rpc_pipe_fs_type);
 989         if (err) {
 990                 kmem_cache_destroy(rpc_inode_cachep);
 991                 return err;
 992         }
 993
 994         return 0;
 995 }
 996
 997 void unregister_rpc_pipefs(void)
 998 {
 999         kmem_cache_destroy(rpc_inode_cachep);
1000         unregister_filesystem(&rpc_pipe_fs_type);
1001 }