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 #include <linux/smp_lock.h>
  31
  32 static struct vfsmount *rpc_mount __read_mostly;
  33 static int rpc_mount_count;
  34
  35 static struct file_system_type rpc_pipe_fs_type;
  36
  37
  38 static struct kmem_cache *rpc_inode_cachep __read_mostly;
  39
  40 #define RPC_UPCALL_TIMEOUT (30*HZ)
  41
  42 static void rpc_purge_list(struct rpc_inode *rpci, struct list_head *head,
  43                 void (*destroy_msg)(struct rpc_pipe_msg *), int err)
  44 {
  45         struct rpc_pipe_msg *msg;
  46
  47         if (list_empty(head))
  48                 return;
  49         do {
  50                 msg = list_entry(head->next, struct rpc_pipe_msg, list);
  51                 list_del_init(&msg->list);
  52                 msg->errno = err;
  53                 destroy_msg(msg);
  54         } while (!list_empty(head));
  55         wake_up(&rpci->waitq);
  56 }
  57
  58 static void
  59 rpc_timeout_upcall_queue(struct work_struct *work)
  60 {
  61         LIST_HEAD(free_list);
  62         struct rpc_inode *rpci =
  63                 container_of(work, struct rpc_inode, queue_timeout.work);
  64         struct inode *inode = &rpci->vfs_inode;
  65         void (*destroy_msg)(struct rpc_pipe_msg *);
  66
  67         spin_lock(&inode->i_lock);
  68         if (rpci->ops == NULL) {
  69                 spin_unlock(&inode->i_lock);
  70                 return;
  71         }
  72         destroy_msg = rpci->ops->destroy_msg;
  73         if (rpci->nreaders == 0) {
  74                 list_splice_init(&rpci->pipe, &free_list);
  75                 rpci->pipelen = 0;
  76         }
  77         spin_unlock(&inode->i_lock);
  78         rpc_purge_list(rpci, &free_list, destroy_msg, -ETIMEDOUT);
  79 }
  80
  81 /**
  82  * rpc_queue_upcall - queue an upcall message to userspace
  83  * @inode: inode of upcall pipe on which to queue given message
  84  * @msg: message to queue
  85  *
  86  * Call with an @inode created by rpc_mkpipe() to queue an upcall.
  87  * A userspace process may then later read the upcall by performing a
  88  * read on an open file for this inode.  It is up to the caller to
  89  * initialize the fields of @msg (other than @msg->list) appropriately.
  90  */
  91 int
  92 rpc_queue_upcall(struct inode *inode, struct rpc_pipe_msg *msg)
  93 {
  94         struct rpc_inode *rpci = RPC_I(inode);
  95         int res = -EPIPE;
  96
  97         spin_lock(&inode->i_lock);
  98         if (rpci->ops == NULL)
  99                 goto out;
 100         if (rpci->nreaders) {
 101                 list_add_tail(&msg->list, &rpci->pipe);
 102                 rpci->pipelen += msg->len;
 103                 res = 0;
 104         } else if (rpci->flags & RPC_PIPE_WAIT_FOR_OPEN) {
 105                 if (list_empty(&rpci->pipe))
 106                         queue_delayed_work(rpciod_workqueue,
 107                                         &rpci->queue_timeout,
 108                                         RPC_UPCALL_TIMEOUT);
 109                 list_add_tail(&msg->list, &rpci->pipe);
 110                 rpci->pipelen += msg->len;
 111                 res = 0;
 112         }
 113 out:
 114         spin_unlock(&inode->i_lock);
 115         wake_up(&rpci->waitq);
 116         return res;
 117 }
 118 EXPORT_SYMBOL_GPL(rpc_queue_upcall);
 119
 120 static inline void
 121 rpc_inode_setowner(struct inode *inode, void *private)
 122 {
 123         RPC_I(inode)->private = private;
 124 }
 125
 126 static void
 127 rpc_close_pipes(struct inode *inode)
 128 {
 129         struct rpc_inode *rpci = RPC_I(inode);
 130         const struct rpc_pipe_ops *ops;
 131         int need_release;
 132
 133         mutex_lock(&inode->i_mutex);
 134         ops = rpci->ops;
 135         if (ops != NULL) {
 136                 LIST_HEAD(free_list);
 137                 spin_lock(&inode->i_lock);
 138                 need_release = rpci->nreaders != 0 || rpci->nwriters != 0;
 139                 rpci->nreaders = 0;
 140                 list_splice_init(&rpci->in_upcall, &free_list);
 141                 list_splice_init(&rpci->pipe, &free_list);
 142                 rpci->pipelen = 0;
 143                 rpci->ops = NULL;
 144                 spin_unlock(&inode->i_lock);
 145                 rpc_purge_list(rpci, &free_list, ops->destroy_msg, -EPIPE);
 146                 rpci->nwriters = 0;
 147                 if (need_release && ops->release_pipe)
 148                         ops->release_pipe(inode);
 149                 cancel_delayed_work_sync(&rpci->queue_timeout);
 150         }
 151         rpc_inode_setowner(inode, NULL);
 152         mutex_unlock(&inode->i_mutex);
 153 }
 154
 155 static struct inode *
 156 rpc_alloc_inode(struct super_block *sb)
 157 {
 158         struct rpc_inode *rpci;
 159         rpci = (struct rpc_inode *)kmem_cache_alloc(rpc_inode_cachep, GFP_KERNEL);
 160         if (!rpci)
 161                 return NULL;
 162         return &rpci->vfs_inode;
 163 }
 164
 165 static void
 166 rpc_destroy_inode(struct inode *inode)
 167 {
 168         kmem_cache_free(rpc_inode_cachep, RPC_I(inode));
 169 }
 170
 171 static int
 172 rpc_pipe_open(struct inode *inode, struct file *filp)
 173 {
 174         struct rpc_inode *rpci = RPC_I(inode);
 175         int first_open;
 176         int res = -ENXIO;
 177
 178         mutex_lock(&inode->i_mutex);
 179         if (rpci->ops == NULL)
 180                 goto out;
 181         first_open = rpci->nreaders == 0 && rpci->nwriters == 0;
 182         if (first_open && rpci->ops->open_pipe) {
 183                 res = rpci->ops->open_pipe(inode);
 184                 if (res)
 185                         goto out;
 186         }
 187         if (filp->f_mode & FMODE_READ)
 188                 rpci->nreaders++;
 189         if (filp->f_mode & FMODE_WRITE)
 190                 rpci->nwriters++;
 191         res = 0;
 192 out:
 193         mutex_unlock(&inode->i_mutex);
 194         return res;
 195 }
 196
 197 static int
 198 rpc_pipe_release(struct inode *inode, struct file *filp)
 199 {
 200         struct rpc_inode *rpci = RPC_I(inode);
 201         struct rpc_pipe_msg *msg;
 202         int last_close;
 203
 204         mutex_lock(&inode->i_mutex);
 205         if (rpci->ops == NULL)
 206                 goto out;
 207         msg = (struct rpc_pipe_msg *)filp->private_data;
 208         if (msg != NULL) {
 209                 spin_lock(&inode->i_lock);
 210                 msg->errno = -EAGAIN;
 211                 list_del_init(&msg->list);
 212                 spin_unlock(&inode->i_lock);
 213                 rpci->ops->destroy_msg(msg);
 214         }
 215         if (filp->f_mode & FMODE_WRITE)
 216                 rpci->nwriters --;
 217         if (filp->f_mode & FMODE_READ) {
 218                 rpci->nreaders --;
 219                 if (rpci->nreaders == 0) {
 220                         LIST_HEAD(free_list);
 221                         spin_lock(&inode->i_lock);
 222                         list_splice_init(&rpci->pipe, &free_list);
 223                         rpci->pipelen = 0;
 224                         spin_unlock(&inode->i_lock);
 225                         rpc_purge_list(rpci, &free_list,
 226                                         rpci->ops->destroy_msg, -EAGAIN);
 227                 }
 228         }
 229         last_close = rpci->nwriters == 0 && rpci->nreaders == 0;
 230         if (last_close && rpci->ops->release_pipe)
 231                 rpci->ops->release_pipe(inode);
 232 out:
 233         mutex_unlock(&inode->i_mutex);
 234         return 0;
 235 }
 236
 237 static ssize_t
 238 rpc_pipe_read(struct file *filp, char __user *buf, size_t len, loff_t *offset)
 239 {
 240         struct inode *inode = filp->f_path.dentry->d_inode;
 241         struct rpc_inode *rpci = RPC_I(inode);
 242         struct rpc_pipe_msg *msg;
 243         int res = 0;
 244
 245         mutex_lock(&inode->i_mutex);
 246         if (rpci->ops == NULL) {
 247                 res = -EPIPE;
 248                 goto out_unlock;
 249         }
 250         msg = filp->private_data;
 251         if (msg == NULL) {
 252                 spin_lock(&inode->i_lock);
 253                 if (!list_empty(&rpci->pipe)) {
 254                         msg = list_entry(rpci->pipe.next,
 255                                         struct rpc_pipe_msg,
 256                                         list);
 257                         list_move(&msg->list, &rpci->in_upcall);
 258                         rpci->pipelen -= msg->len;
 259                         filp->private_data = msg;
 260                         msg->copied = 0;
 261                 }
 262                 spin_unlock(&inode->i_lock);
 263                 if (msg == NULL)
 264                         goto out_unlock;
 265         }
 266         /* NOTE: it is up to the callback to update msg->copied */
 267         res = rpci->ops->upcall(filp, msg, buf, len);
 268         if (res < 0 || msg->len == msg->copied) {
 269                 filp->private_data = NULL;
 270                 spin_lock(&inode->i_lock);
 271                 list_del_init(&msg->list);
 272                 spin_unlock(&inode->i_lock);
 273                 rpci->ops->destroy_msg(msg);
 274         }
 275 out_unlock:
 276         mutex_unlock(&inode->i_mutex);
 277         return res;
 278 }
 279
 280 static ssize_t
 281 rpc_pipe_write(struct file *filp, const char __user *buf, size_t len, loff_t *offset)
 282 {
 283         struct inode *inode = filp->f_path.dentry->d_inode;
 284         struct rpc_inode *rpci = RPC_I(inode);
 285         int res;
 286
 287         mutex_lock(&inode->i_mutex);
 288         res = -EPIPE;
 289         if (rpci->ops != NULL)
 290                 res = rpci->ops->downcall(filp, buf, len);
 291         mutex_unlock(&inode->i_mutex);
 292         return res;
 293 }
 294
 295 static unsigned int
 296 rpc_pipe_poll(struct file *filp, struct poll_table_struct *wait)
 297 {
 298         struct rpc_inode *rpci;
 299         unsigned int mask = 0;
 300
 301         rpci = RPC_I(filp->f_path.dentry->d_inode);
 302         poll_wait(filp, &rpci->waitq, wait);
 303
 304         mask = POLLOUT | POLLWRNORM;
 305         if (rpci->ops == NULL)
 306                 mask |= POLLERR | POLLHUP;
 307         if (filp->private_data || !list_empty(&rpci->pipe))
 308                 mask |= POLLIN | POLLRDNORM;
 309         return mask;
 310 }
 311
 312 static int
 313 rpc_pipe_ioctl_unlocked(struct file *filp, unsigned int cmd, unsigned long arg)
 314 {
 315         struct rpc_inode *rpci = RPC_I(filp->f_path.dentry->d_inode);
 316         int len;
 317
 318         switch (cmd) {
 319         case FIONREAD:
 320                 if (rpci->ops == NULL)
 321                         return -EPIPE;
 322                 len = rpci->pipelen;
 323                 if (filp->private_data) {
 324                         struct rpc_pipe_msg *msg;
 325                         msg = (struct rpc_pipe_msg *)filp->private_data;
 326                         len += msg->len - msg->copied;
 327                 }
 328                 return put_user(len, (int __user *)arg);
 329         default:
 330                 return -EINVAL;
 331         }
 332 }
 333
 334 static long
 335 rpc_pipe_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 336 {
 337         long ret;
 338
 339         lock_kernel();
 340         ret = rpc_pipe_ioctl_unlocked(filp, cmd, arg);
 341         unlock_kernel();
 342
 343         return ret;
 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_mount, &rpc_mount_count);
 429         if (err != 0)
 430                 return ERR_PTR(err);
 431         return rpc_mount;
 432 }
 433 EXPORT_SYMBOL_GPL(rpc_get_mount);
 434
 435 void rpc_put_mount(void)
 436 {
 437         simple_release_fs(&rpc_mount, &rpc_mount_count);
 438 }
 439 EXPORT_SYMBOL_GPL(rpc_put_mount);
 440
 441 static int rpc_delete_dentry(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_mode = mode;
 457         inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
 458         switch(mode & S_IFMT) {
 459                 case S_IFDIR:
 460                         inode->i_fop = &simple_dir_operations;
 461                         inode->i_op = &simple_dir_inode_operations;
 462                         inc_nlink(inode);
 463                 default:
 464                         break;
 465         }
 466         return inode;
 467 }
 468
 469 static int __rpc_create_common(struct inode *dir, struct dentry *dentry,
 470                                umode_t mode,
 471                                const struct file_operations *i_fop,
 472                                void *private)
 473 {
 474         struct inode *inode;
 475
 476         BUG_ON(!d_unhashed(dentry));
 477         inode = rpc_get_inode(dir->i_sb, mode);
 478         if (!inode)
 479                 goto out_err;
 480         inode->i_ino = iunique(dir->i_sb, 100);
 481         if (i_fop)
 482                 inode->i_fop = i_fop;
 483         if (private)
 484                 rpc_inode_setowner(inode, private);
 485         d_add(dentry, inode);
 486         return 0;
 487 out_err:
 488         printk(KERN_WARNING "%s: %s failed to allocate inode for dentry %s\n",
 489                         __FILE__, __func__, dentry->d_name.name);
 490         dput(dentry);
 491         return -ENOMEM;
 492 }
 493
 494 static int __rpc_create(struct inode *dir, struct dentry *dentry,
 495                         umode_t mode,
 496                         const struct file_operations *i_fop,
 497                         void *private)
 498 {
 499         int err;
 500
 501         err = __rpc_create_common(dir, dentry, S_IFREG | mode, i_fop, private);
 502         if (err)
 503                 return err;
 504         fsnotify_create(dir, dentry);
 505         return 0;
 506 }
 507
 508 static int __rpc_mkdir(struct inode *dir, struct dentry *dentry,
 509                        umode_t mode,
 510                        const struct file_operations *i_fop,
 511                        void *private)
 512 {
 513         int err;
 514
 515         err = __rpc_create_common(dir, dentry, S_IFDIR | mode, i_fop, private);
 516         if (err)
 517                 return err;
 518         inc_nlink(dir);
 519         fsnotify_mkdir(dir, dentry);
 520         return 0;
 521 }
 522
 523 static int __rpc_mkpipe(struct inode *dir, struct dentry *dentry,
 524                         umode_t mode,
 525                         const struct file_operations *i_fop,
 526                         void *private,
 527                         const struct rpc_pipe_ops *ops,
 528                         int flags)
 529 {
 530         struct rpc_inode *rpci;
 531         int err;
 532
 533         err = __rpc_create_common(dir, dentry, S_IFIFO | mode, i_fop, private);
 534         if (err)
 535                 return err;
 536         rpci = RPC_I(dentry->d_inode);
 537         rpci->nkern_readwriters = 1;
 538         rpci->private = private;
 539         rpci->flags = flags;
 540         rpci->ops = ops;
 541         fsnotify_create(dir, dentry);
 542         return 0;
 543 }
 544
 545 static int __rpc_rmdir(struct inode *dir, struct dentry *dentry)
 546 {
 547         int ret;
 548
 549         dget(dentry);
 550         ret = simple_rmdir(dir, dentry);
 551         d_delete(dentry);
 552         dput(dentry);
 553         return ret;
 554 }
 555
 556 static int __rpc_unlink(struct inode *dir, struct dentry *dentry)
 557 {
 558         int ret;
 559
 560         dget(dentry);
 561         ret = simple_unlink(dir, dentry);
 562         d_delete(dentry);
 563         dput(dentry);
 564         return ret;
 565 }
 566
 567 static int __rpc_rmpipe(struct inode *dir, struct dentry *dentry)
 568 {
 569         struct inode *inode = dentry->d_inode;
 570         struct rpc_inode *rpci = RPC_I(inode);
 571
 572         rpci->nkern_readwriters--;
 573         if (rpci->nkern_readwriters != 0)
 574                 return 0;
 575         rpc_close_pipes(inode);
 576         return __rpc_unlink(dir, dentry);
 577 }
 578
 579 static struct dentry *__rpc_lookup_create(struct dentry *parent,
 580                                           struct qstr *name)
 581 {
 582         struct dentry *dentry;
 583
 584         dentry = d_lookup(parent, name);
 585         if (!dentry) {
 586                 dentry = d_alloc(parent, name);
 587                 if (!dentry) {
 588                         dentry = ERR_PTR(-ENOMEM);
 589                         goto out_err;
 590                 }
 591         }
 592         if (!dentry->d_inode)
 593                 dentry->d_op = &rpc_dentry_operations;
 594 out_err:
 595         return dentry;
 596 }
 597
 598 static struct dentry *__rpc_lookup_create_exclusive(struct dentry *parent,
 599                                           struct qstr *name)
 600 {
 601         struct dentry *dentry;
 602
 603         dentry = __rpc_lookup_create(parent, name);
 604         if (IS_ERR(dentry))
 605                 return dentry;
 606         if (dentry->d_inode == NULL)
 607                 return dentry;
 608         dput(dentry);
 609         return ERR_PTR(-EEXIST);
 610 }
 611
 612 /*
 613  * FIXME: This probably has races.
 614  */
 615 static void __rpc_depopulate(struct dentry *parent,
 616                              const struct rpc_filelist *files,
 617                              int start, int eof)
 618 {
 619         struct inode *dir = parent->d_inode;
 620         struct dentry *dentry;
 621         struct qstr name;
 622         int i;
 623
 624         for (i = start; i < eof; i++) {
 625                 name.name = files[i].name;
 626                 name.len = strlen(files[i].name);
 627                 name.hash = full_name_hash(name.name, name.len);
 628                 dentry = d_lookup(parent, &name);
 629
 630                 if (dentry == NULL)
 631                         continue;
 632                 if (dentry->d_inode == NULL)
 633                         goto next;
 634                 switch (dentry->d_inode->i_mode & S_IFMT) {
 635                         default:
 636                                 BUG();
 637                         case S_IFREG:
 638                                 __rpc_unlink(dir, dentry);
 639                                 break;
 640                         case S_IFDIR:
 641                                 __rpc_rmdir(dir, dentry);
 642                 }
 643 next:
 644                 dput(dentry);
 645         }
 646 }
 647
 648 static void rpc_depopulate(struct dentry *parent,
 649                            const struct rpc_filelist *files,
 650                            int start, int eof)
 651 {
 652         struct inode *dir = parent->d_inode;
 653
 654         mutex_lock_nested(&dir->i_mutex, I_MUTEX_CHILD);
 655         __rpc_depopulate(parent, files, start, eof);
 656         mutex_unlock(&dir->i_mutex);
 657 }
 658
 659 static int rpc_populate(struct dentry *parent,
 660                         const struct rpc_filelist *files,
 661                         int start, int eof,
 662                         void *private)
 663 {
 664         struct inode *dir = parent->d_inode;
 665         struct dentry *dentry;
 666         int i, err;
 667
 668         mutex_lock(&dir->i_mutex);
 669         for (i = start; i < eof; i++) {
 670                 struct qstr q;
 671
 672                 q.name = files[i].name;
 673                 q.len = strlen(files[i].name);
 674                 q.hash = full_name_hash(q.name, q.len);
 675                 dentry = __rpc_lookup_create_exclusive(parent, &q);
 676                 err = PTR_ERR(dentry);
 677                 if (IS_ERR(dentry))
 678                         goto out_bad;
 679                 switch (files[i].mode & S_IFMT) {
 680                         default:
 681                                 BUG();
 682                         case S_IFREG:
 683                                 err = __rpc_create(dir, dentry,
 684                                                 files[i].mode,
 685                                                 files[i].i_fop,
 686                                                 private);
 687                                 break;
 688                         case S_IFDIR:
 689                                 err = __rpc_mkdir(dir, dentry,
 690                                                 files[i].mode,
 691                                                 NULL,
 692                                                 private);
 693                 }
 694                 if (err != 0)
 695                         goto out_bad;
 696         }
 697         mutex_unlock(&dir->i_mutex);
 698         return 0;
 699 out_bad:
 700         __rpc_depopulate(parent, files, start, eof);
 701         mutex_unlock(&dir->i_mutex);
 702         printk(KERN_WARNING "%s: %s failed to populate directory %s\n",
 703                         __FILE__, __func__, parent->d_name.name);
 704         return err;
 705 }
 706
 707 static struct dentry *rpc_mkdir_populate(struct dentry *parent,
 708                 struct qstr *name, umode_t mode, void *private,
 709                 int (*populate)(struct dentry *, void *), void *args_populate)
 710 {
 711         struct dentry *dentry;
 712         struct inode *dir = parent->d_inode;
 713         int error;
 714
 715         mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
 716         dentry = __rpc_lookup_create_exclusive(parent, name);
 717         if (IS_ERR(dentry))
 718                 goto out;
 719         error = __rpc_mkdir(dir, dentry, mode, NULL, private);
 720         if (error != 0)
 721                 goto out_err;
 722         if (populate != NULL) {
 723                 error = populate(dentry, args_populate);
 724                 if (error)
 725                         goto err_rmdir;
 726         }
 727 out:
 728         mutex_unlock(&dir->i_mutex);
 729         return dentry;
 730 err_rmdir:
 731         __rpc_rmdir(dir, dentry);
 732 out_err:
 733         dentry = ERR_PTR(error);
 734         goto out;
 735 }
 736
 737 static int rpc_rmdir_depopulate(struct dentry *dentry,
 738                 void (*depopulate)(struct dentry *))
 739 {
 740         struct dentry *parent;
 741         struct inode *dir;
 742         int error;
 743
 744         parent = dget_parent(dentry);
 745         dir = parent->d_inode;
 746         mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
 747         if (depopulate != NULL)
 748                 depopulate(dentry);
 749         error = __rpc_rmdir(dir, dentry);
 750         mutex_unlock(&dir->i_mutex);
 751         dput(parent);
 752         return error;
 753 }
 754
 755 /**
 756  * rpc_mkpipe - make an rpc_pipefs file for kernel<->userspace communication
 757  * @parent: dentry of directory to create new "pipe" in
 758  * @name: name of pipe
 759  * @private: private data to associate with the pipe, for the caller's use
 760  * @ops: operations defining the behavior of the pipe: upcall, downcall,
 761  *      release_pipe, open_pipe, and destroy_msg.
 762  * @flags: rpc_inode flags
 763  *
 764  * Data is made available for userspace to read by calls to
 765  * rpc_queue_upcall().  The actual reads will result in calls to
 766  * @ops->upcall, which will be called with the file pointer,
 767  * message, and userspace buffer to copy to.
 768  *
 769  * Writes can come at any time, and do not necessarily have to be
 770  * responses to upcalls.  They will result in calls to @msg->downcall.
 771  *
 772  * The @private argument passed here will be available to all these methods
 773  * from the file pointer, via RPC_I(file->f_dentry->d_inode)->private.
 774  */
 775 struct dentry *rpc_mkpipe(struct dentry *parent, const char *name,
 776                           void *private, const struct rpc_pipe_ops *ops,
 777                           int flags)
 778 {
 779         struct dentry *dentry;
 780         struct inode *dir = parent->d_inode;
 781         umode_t umode = S_IFIFO | S_IRUSR | S_IWUSR;
 782         struct qstr q;
 783         int err;
 784
 785         if (ops->upcall == NULL)
 786                 umode &= ~S_IRUGO;
 787         if (ops->downcall == NULL)
 788                 umode &= ~S_IWUGO;
 789
 790         q.name = name;
 791         q.len = strlen(name);
 792         q.hash = full_name_hash(q.name, q.len),
 793
 794         mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
 795         dentry = __rpc_lookup_create(parent, &q);
 796         if (IS_ERR(dentry))
 797                 goto out;
 798         if (dentry->d_inode) {
 799                 struct rpc_inode *rpci = RPC_I(dentry->d_inode);
 800                 if (rpci->private != private ||
 801                                 rpci->ops != ops ||
 802                                 rpci->flags != flags) {
 803                         dput (dentry);
 804                         err = -EBUSY;
 805                         goto out_err;
 806                 }
 807                 rpci->nkern_readwriters++;
 808                 goto out;
 809         }
 810
 811         err = __rpc_mkpipe(dir, dentry, umode, &rpc_pipe_fops,
 812                            private, ops, flags);
 813         if (err)
 814                 goto out_err;
 815 out:
 816         mutex_unlock(&dir->i_mutex);
 817         return dentry;
 818 out_err:
 819         dentry = ERR_PTR(err);
 820         printk(KERN_WARNING "%s: %s() failed to create pipe %s/%s (errno = %d)\n",
 821                         __FILE__, __func__, parent->d_name.name, name,
 822                         err);
 823         goto out;
 824 }
 825 EXPORT_SYMBOL_GPL(rpc_mkpipe);
 826
 827 /**
 828  * rpc_unlink - remove a pipe
 829  * @dentry: dentry for the pipe, as returned from rpc_mkpipe
 830  *
 831  * After this call, lookups will no longer find the pipe, and any
 832  * attempts to read or write using preexisting opens of the pipe will
 833  * return -EPIPE.
 834  */
 835 int
 836 rpc_unlink(struct dentry *dentry)
 837 {
 838         struct dentry *parent;
 839         struct inode *dir;
 840         int error = 0;
 841
 842         parent = dget_parent(dentry);
 843         dir = parent->d_inode;
 844         mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
 845         error = __rpc_rmpipe(dir, dentry);
 846         mutex_unlock(&dir->i_mutex);
 847         dput(parent);
 848         return error;
 849 }
 850 EXPORT_SYMBOL_GPL(rpc_unlink);
 851
 852 enum {
 853         RPCAUTH_info,
 854         RPCAUTH_EOF
 855 };
 856
 857 static const struct rpc_filelist authfiles[] = {
 858         [RPCAUTH_info] = {
 859                 .name = "info",
 860                 .i_fop = &rpc_info_operations,
 861                 .mode = S_IFREG | S_IRUSR,
 862         },
 863 };
 864
 865 static int rpc_clntdir_populate(struct dentry *dentry, void *private)
 866 {
 867         return rpc_populate(dentry,
 868                             authfiles, RPCAUTH_info, RPCAUTH_EOF,
 869                             private);
 870 }
 871
 872 static void rpc_clntdir_depopulate(struct dentry *dentry)
 873 {
 874         rpc_depopulate(dentry, authfiles, RPCAUTH_info, RPCAUTH_EOF);
 875 }
 876
 877 /**
 878  * rpc_create_client_dir - Create a new rpc_client directory in rpc_pipefs
 879  * @dentry: dentry from the rpc_pipefs root to the new directory
 880  * @name: &struct qstr for the name
 881  * @rpc_client: rpc client to associate with this directory
 882  *
 883  * This creates a directory at the given @path associated with
 884  * @rpc_clnt, which will contain a file named "info" with some basic
 885  * information about the client, together with any "pipes" that may
 886  * later be created using rpc_mkpipe().
 887  */
 888 struct dentry *rpc_create_client_dir(struct dentry *dentry,
 889                                    struct qstr *name,
 890                                    struct rpc_clnt *rpc_client)
 891 {
 892         return rpc_mkdir_populate(dentry, name, S_IRUGO | S_IXUGO, NULL,
 893                         rpc_clntdir_populate, rpc_client);
 894 }
 895
 896 /**
 897  * rpc_remove_client_dir - Remove a directory created with rpc_create_client_dir()
 898  * @dentry: directory to remove
 899  */
 900 int rpc_remove_client_dir(struct dentry *dentry)
 901 {
 902         return rpc_rmdir_depopulate(dentry, rpc_clntdir_depopulate);
 903 }
 904
 905 static const struct rpc_filelist cache_pipefs_files[3] = {
 906         [0] = {
 907                 .name = "channel",
 908                 .i_fop = &cache_file_operations_pipefs,
 909                 .mode = S_IFREG|S_IRUSR|S_IWUSR,
 910         },
 911         [1] = {
 912                 .name = "content",
 913                 .i_fop = &content_file_operations_pipefs,
 914                 .mode = S_IFREG|S_IRUSR,
 915         },
 916         [2] = {
 917                 .name = "flush",
 918                 .i_fop = &cache_flush_operations_pipefs,
 919                 .mode = S_IFREG|S_IRUSR|S_IWUSR,
 920         },
 921 };
 922
 923 static int rpc_cachedir_populate(struct dentry *dentry, void *private)
 924 {
 925         return rpc_populate(dentry,
 926                             cache_pipefs_files, 0, 3,
 927                             private);
 928 }
 929
 930 static void rpc_cachedir_depopulate(struct dentry *dentry)
 931 {
 932         rpc_depopulate(dentry, cache_pipefs_files, 0, 3);
 933 }
 934
 935 struct dentry *rpc_create_cache_dir(struct dentry *parent, struct qstr *name,
 936                                     mode_t umode, struct cache_detail *cd)
 937 {
 938         return rpc_mkdir_populate(parent, name, umode, NULL,
 939                         rpc_cachedir_populate, cd);
 940 }
 941
 942 void rpc_remove_cache_dir(struct dentry *dentry)
 943 {
 944         rpc_rmdir_depopulate(dentry, rpc_cachedir_depopulate);
 945 }
 946
 947 /*
 948  * populate the filesystem
 949  */
 950 static const struct super_operations s_ops = {
 951         .alloc_inode    = rpc_alloc_inode,
 952         .destroy_inode  = rpc_destroy_inode,
 953         .statfs         = simple_statfs,
 954 };
 955
 956 #define RPCAUTH_GSSMAGIC 0x67596969
 957
 958 /*
 959  * We have a single directory with 1 node in it.
 960  */
 961 enum {
 962         RPCAUTH_lockd,
 963         RPCAUTH_mount,
 964         RPCAUTH_nfs,
 965         RPCAUTH_portmap,
 966         RPCAUTH_statd,
 967         RPCAUTH_nfsd4_cb,
 968         RPCAUTH_cache,
 969         RPCAUTH_RootEOF
 970 };
 971
 972 static const struct rpc_filelist files[] = {
 973         [RPCAUTH_lockd] = {
 974                 .name = "lockd",
 975                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
 976         },
 977         [RPCAUTH_mount] = {
 978                 .name = "mount",
 979                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
 980         },
 981         [RPCAUTH_nfs] = {
 982                 .name = "nfs",
 983                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
 984         },
 985         [RPCAUTH_portmap] = {
 986                 .name = "portmap",
 987                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
 988         },
 989         [RPCAUTH_statd] = {
 990                 .name = "statd",
 991                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
 992         },
 993         [RPCAUTH_nfsd4_cb] = {
 994                 .name = "nfsd4_cb",
 995                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
 996         },
 997         [RPCAUTH_cache] = {
 998                 .name = "cache",
 999                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
1000         },
1001 };
1002
1003 static int
1004 rpc_fill_super(struct super_block *sb, void *data, int silent)
1005 {
1006         struct inode *inode;
1007         struct dentry *root;
1008
1009         sb->s_blocksize = PAGE_CACHE_SIZE;
1010         sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
1011         sb->s_magic = RPCAUTH_GSSMAGIC;
1012         sb->s_op = &s_ops;
1013         sb->s_time_gran = 1;
1014
1015         inode = rpc_get_inode(sb, S_IFDIR | 0755);
1016         if (!inode)
1017                 return -ENOMEM;
1018         sb->s_root = root = d_alloc_root(inode);
1019         if (!root) {
1020                 iput(inode);
1021                 return -ENOMEM;
1022         }
1023         if (rpc_populate(root, files, RPCAUTH_lockd, RPCAUTH_RootEOF, NULL))
1024                 return -ENOMEM;
1025         return 0;
1026 }
1027
1028 static int
1029 rpc_get_sb(struct file_system_type *fs_type,
1030                 int flags, const char *dev_name, void *data, struct vfsmount *mnt)
1031 {
1032         return get_sb_single(fs_type, flags, data, rpc_fill_super, mnt);
1033 }
1034
1035 static struct file_system_type rpc_pipe_fs_type = {
1036         .owner          = THIS_MODULE,
1037         .name           = "rpc_pipefs",
1038         .get_sb         = rpc_get_sb,
1039         .kill_sb        = kill_litter_super,
1040 };
1041
1042 static void
1043 init_once(void *foo)
1044 {
1045         struct rpc_inode *rpci = (struct rpc_inode *) foo;
1046
1047         inode_init_once(&rpci->vfs_inode);
1048         rpci->private = NULL;
1049         rpci->nreaders = 0;
1050         rpci->nwriters = 0;
1051         INIT_LIST_HEAD(&rpci->in_upcall);
1052         INIT_LIST_HEAD(&rpci->in_downcall);
1053         INIT_LIST_HEAD(&rpci->pipe);
1054         rpci->pipelen = 0;
1055         init_waitqueue_head(&rpci->waitq);
1056         INIT_DELAYED_WORK(&rpci->queue_timeout,
1057                             rpc_timeout_upcall_queue);
1058         rpci->ops = NULL;
1059 }
1060
1061 int register_rpc_pipefs(void)
1062 {
1063         int err;
1064
1065         rpc_inode_cachep = kmem_cache_create("rpc_inode_cache",
1066                                 sizeof(struct rpc_inode),
1067                                 0, (SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT|
1068                                                 SLAB_MEM_SPREAD),
1069                                 init_once);
1070         if (!rpc_inode_cachep)
1071                 return -ENOMEM;
1072         err = register_filesystem(&rpc_pipe_fs_type);
1073         if (err) {
1074                 kmem_cache_destroy(rpc_inode_cachep);
1075                 return err;
1076         }
1077
1078         return 0;
1079 }
1080
1081 void unregister_rpc_pipefs(void)
1082 {
1083         kmem_cache_destroy(rpc_inode_cachep);
1084         unregister_filesystem(&rpc_pipe_fs_type);
1085 }