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(&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(&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(&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;
 375         int ret = single_open(file, rpc_show_info, NULL);
 376
 377         if (!ret) {
 378                 struct seq_file *m = file->private_data;
 379                 mutex_lock(&inode->i_mutex);
 380                 clnt = RPC_I(inode)->private;
 381                 if (clnt) {
 382                         kref_get(&clnt->cl_kref);
 383                         m->private = clnt;
 384                 } else {
 385                         single_release(inode, file);
 386                         ret = -EINVAL;
 387                 }
 388                 mutex_unlock(&inode->i_mutex);
 389         }
 390         return ret;
 391 }
 392
 393 static int
 394 rpc_info_release(struct inode *inode, struct file *file)
 395 {
 396         struct seq_file *m = file->private_data;
 397         struct rpc_clnt *clnt = (struct rpc_clnt *)m->private;
 398
 399         if (clnt)
 400                 rpc_release_client(clnt);
 401         return single_release(inode, file);
 402 }
 403
 404 static const struct file_operations rpc_info_operations = {
 405         .owner          = THIS_MODULE,
 406         .open           = rpc_info_open,
 407         .read           = seq_read,
 408         .llseek         = seq_lseek,
 409         .release        = rpc_info_release,
 410 };
 411
 412
 413 /*
 414  * Description of fs contents.
 415  */
 416 struct rpc_filelist {
 417         const char *name;
 418         const struct file_operations *i_fop;
 419         umode_t mode;
 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 EXPORT_SYMBOL_GPL(rpc_get_mount);
 432
 433 void rpc_put_mount(void)
 434 {
 435         simple_release_fs(&rpc_mount, &rpc_mount_count);
 436 }
 437 EXPORT_SYMBOL_GPL(rpc_put_mount);
 438
 439 static int rpc_delete_dentry(struct dentry *dentry)
 440 {
 441         return 1;
 442 }
 443
 444 static const struct dentry_operations rpc_dentry_operations = {
 445         .d_delete = rpc_delete_dentry,
 446 };
 447
 448 static struct inode *
 449 rpc_get_inode(struct super_block *sb, umode_t mode)
 450 {
 451         struct inode *inode = new_inode(sb);
 452         if (!inode)
 453                 return NULL;
 454         inode->i_mode = mode;
 455         inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
 456         switch(mode & S_IFMT) {
 457                 case S_IFDIR:
 458                         inode->i_fop = &simple_dir_operations;
 459                         inode->i_op = &simple_dir_inode_operations;
 460                         inc_nlink(inode);
 461                 default:
 462                         break;
 463         }
 464         return inode;
 465 }
 466
 467 static int __rpc_create_common(struct inode *dir, struct dentry *dentry,
 468                                umode_t mode,
 469                                const struct file_operations *i_fop,
 470                                void *private)
 471 {
 472         struct inode *inode;
 473
 474         BUG_ON(!d_unhashed(dentry));
 475         inode = rpc_get_inode(dir->i_sb, mode);
 476         if (!inode)
 477                 goto out_err;
 478         inode->i_ino = iunique(dir->i_sb, 100);
 479         if (i_fop)
 480                 inode->i_fop = i_fop;
 481         if (private)
 482                 rpc_inode_setowner(inode, private);
 483         d_add(dentry, inode);
 484         return 0;
 485 out_err:
 486         printk(KERN_WARNING "%s: %s failed to allocate inode for dentry %s\n",
 487                         __FILE__, __func__, dentry->d_name.name);
 488         dput(dentry);
 489         return -ENOMEM;
 490 }
 491
 492 static int __rpc_create(struct inode *dir, struct dentry *dentry,
 493                         umode_t mode,
 494                         const struct file_operations *i_fop,
 495                         void *private)
 496 {
 497         int err;
 498
 499         err = __rpc_create_common(dir, dentry, S_IFREG | mode, i_fop, private);
 500         if (err)
 501                 return err;
 502         fsnotify_create(dir, dentry);
 503         return 0;
 504 }
 505
 506 static int __rpc_mkdir(struct inode *dir, struct dentry *dentry,
 507                        umode_t mode,
 508                        const struct file_operations *i_fop,
 509                        void *private)
 510 {
 511         int err;
 512
 513         err = __rpc_create_common(dir, dentry, S_IFDIR | mode, i_fop, private);
 514         if (err)
 515                 return err;
 516         inc_nlink(dir);
 517         fsnotify_mkdir(dir, dentry);
 518         return 0;
 519 }
 520
 521 static int __rpc_mkpipe(struct inode *dir, struct dentry *dentry,
 522                         umode_t mode,
 523                         const struct file_operations *i_fop,
 524                         void *private,
 525                         const struct rpc_pipe_ops *ops,
 526                         int flags)
 527 {
 528         struct rpc_inode *rpci;
 529         int err;
 530
 531         err = __rpc_create_common(dir, dentry, S_IFIFO | mode, i_fop, private);
 532         if (err)
 533                 return err;
 534         rpci = RPC_I(dentry->d_inode);
 535         rpci->nkern_readwriters = 1;
 536         rpci->private = private;
 537         rpci->flags = flags;
 538         rpci->ops = ops;
 539         fsnotify_create(dir, dentry);
 540         return 0;
 541 }
 542
 543 static int __rpc_rmdir(struct inode *dir, struct dentry *dentry)
 544 {
 545         int ret;
 546
 547         dget(dentry);
 548         ret = simple_rmdir(dir, dentry);
 549         d_delete(dentry);
 550         dput(dentry);
 551         return ret;
 552 }
 553
 554 static int __rpc_unlink(struct inode *dir, struct dentry *dentry)
 555 {
 556         int ret;
 557
 558         dget(dentry);
 559         ret = simple_unlink(dir, dentry);
 560         d_delete(dentry);
 561         dput(dentry);
 562         return ret;
 563 }
 564
 565 static int __rpc_rmpipe(struct inode *dir, struct dentry *dentry)
 566 {
 567         struct inode *inode = dentry->d_inode;
 568         struct rpc_inode *rpci = RPC_I(inode);
 569
 570         rpci->nkern_readwriters--;
 571         if (rpci->nkern_readwriters != 0)
 572                 return 0;
 573         rpc_close_pipes(inode);
 574         return __rpc_unlink(dir, dentry);
 575 }
 576
 577 static struct dentry *__rpc_lookup_create(struct dentry *parent,
 578                                           struct qstr *name)
 579 {
 580         struct dentry *dentry;
 581
 582         dentry = d_lookup(parent, name);
 583         if (!dentry) {
 584                 dentry = d_alloc(parent, name);
 585                 if (!dentry) {
 586                         dentry = ERR_PTR(-ENOMEM);
 587                         goto out_err;
 588                 }
 589         }
 590         if (!dentry->d_inode)
 591                 dentry->d_op = &rpc_dentry_operations;
 592 out_err:
 593         return dentry;
 594 }
 595
 596 static struct dentry *__rpc_lookup_create_exclusive(struct dentry *parent,
 597                                           struct qstr *name)
 598 {
 599         struct dentry *dentry;
 600
 601         dentry = __rpc_lookup_create(parent, name);
 602         if (IS_ERR(dentry))
 603                 return dentry;
 604         if (dentry->d_inode == NULL)
 605                 return dentry;
 606         dput(dentry);
 607         return ERR_PTR(-EEXIST);
 608 }
 609
 610 /*
 611  * FIXME: This probably has races.
 612  */
 613 static void __rpc_depopulate(struct dentry *parent,
 614                              const struct rpc_filelist *files,
 615                              int start, int eof)
 616 {
 617         struct inode *dir = parent->d_inode;
 618         struct dentry *dentry;
 619         struct qstr name;
 620         int i;
 621
 622         for (i = start; i < eof; i++) {
 623                 name.name = files[i].name;
 624                 name.len = strlen(files[i].name);
 625                 name.hash = full_name_hash(name.name, name.len);
 626                 dentry = d_lookup(parent, &name);
 627
 628                 if (dentry == NULL)
 629                         continue;
 630                 if (dentry->d_inode == NULL)
 631                         goto next;
 632                 switch (dentry->d_inode->i_mode & S_IFMT) {
 633                         default:
 634                                 BUG();
 635                         case S_IFREG:
 636                                 __rpc_unlink(dir, dentry);
 637                                 break;
 638                         case S_IFDIR:
 639                                 __rpc_rmdir(dir, dentry);
 640                 }
 641 next:
 642                 dput(dentry);
 643         }
 644 }
 645
 646 static void rpc_depopulate(struct dentry *parent,
 647                            const struct rpc_filelist *files,
 648                            int start, int eof)
 649 {
 650         struct inode *dir = parent->d_inode;
 651
 652         mutex_lock_nested(&dir->i_mutex, I_MUTEX_CHILD);
 653         __rpc_depopulate(parent, files, start, eof);
 654         mutex_unlock(&dir->i_mutex);
 655 }
 656
 657 static int rpc_populate(struct dentry *parent,
 658                         const struct rpc_filelist *files,
 659                         int start, int eof,
 660                         void *private)
 661 {
 662         struct inode *dir = parent->d_inode;
 663         struct dentry *dentry;
 664         int i, err;
 665
 666         mutex_lock(&dir->i_mutex);
 667         for (i = start; i < eof; i++) {
 668                 struct qstr q;
 669
 670                 q.name = files[i].name;
 671                 q.len = strlen(files[i].name);
 672                 q.hash = full_name_hash(q.name, q.len);
 673                 dentry = __rpc_lookup_create_exclusive(parent, &q);
 674                 err = PTR_ERR(dentry);
 675                 if (IS_ERR(dentry))
 676                         goto out_bad;
 677                 switch (files[i].mode & S_IFMT) {
 678                         default:
 679                                 BUG();
 680                         case S_IFREG:
 681                                 err = __rpc_create(dir, dentry,
 682                                                 files[i].mode,
 683                                                 files[i].i_fop,
 684                                                 private);
 685                                 break;
 686                         case S_IFDIR:
 687                                 err = __rpc_mkdir(dir, dentry,
 688                                                 files[i].mode,
 689                                                 NULL,
 690                                                 private);
 691                 }
 692                 if (err != 0)
 693                         goto out_bad;
 694         }
 695         mutex_unlock(&dir->i_mutex);
 696         return 0;
 697 out_bad:
 698         __rpc_depopulate(parent, files, start, eof);
 699         mutex_unlock(&dir->i_mutex);
 700         printk(KERN_WARNING "%s: %s failed to populate directory %s\n",
 701                         __FILE__, __func__, parent->d_name.name);
 702         return err;
 703 }
 704
 705 static struct dentry *rpc_mkdir_populate(struct dentry *parent,
 706                 struct qstr *name, umode_t mode, void *private,
 707                 int (*populate)(struct dentry *, void *), void *args_populate)
 708 {
 709         struct dentry *dentry;
 710         struct inode *dir = parent->d_inode;
 711         int error;
 712
 713         mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
 714         dentry = __rpc_lookup_create_exclusive(parent, name);
 715         if (IS_ERR(dentry))
 716                 goto out;
 717         error = __rpc_mkdir(dir, dentry, mode, NULL, private);
 718         if (error != 0)
 719                 goto out_err;
 720         if (populate != NULL) {
 721                 error = populate(dentry, args_populate);
 722                 if (error)
 723                         goto err_rmdir;
 724         }
 725 out:
 726         mutex_unlock(&dir->i_mutex);
 727         return dentry;
 728 err_rmdir:
 729         __rpc_rmdir(dir, dentry);
 730 out_err:
 731         dentry = ERR_PTR(error);
 732         goto out;
 733 }
 734
 735 static int rpc_rmdir_depopulate(struct dentry *dentry,
 736                 void (*depopulate)(struct dentry *))
 737 {
 738         struct dentry *parent;
 739         struct inode *dir;
 740         int error;
 741
 742         parent = dget_parent(dentry);
 743         dir = parent->d_inode;
 744         mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
 745         if (depopulate != NULL)
 746                 depopulate(dentry);
 747         error = __rpc_rmdir(dir, dentry);
 748         mutex_unlock(&dir->i_mutex);
 749         dput(parent);
 750         return error;
 751 }
 752
 753 /**
 754  * rpc_mkpipe - make an rpc_pipefs file for kernel<->userspace communication
 755  * @parent: dentry of directory to create new "pipe" in
 756  * @name: name of pipe
 757  * @private: private data to associate with the pipe, for the caller's use
 758  * @ops: operations defining the behavior of the pipe: upcall, downcall,
 759  *      release_pipe, open_pipe, and destroy_msg.
 760  * @flags: rpc_inode flags
 761  *
 762  * Data is made available for userspace to read by calls to
 763  * rpc_queue_upcall().  The actual reads will result in calls to
 764  * @ops->upcall, which will be called with the file pointer,
 765  * message, and userspace buffer to copy to.
 766  *
 767  * Writes can come at any time, and do not necessarily have to be
 768  * responses to upcalls.  They will result in calls to @msg->downcall.
 769  *
 770  * The @private argument passed here will be available to all these methods
 771  * from the file pointer, via RPC_I(file->f_dentry->d_inode)->private.
 772  */
 773 struct dentry *rpc_mkpipe(struct dentry *parent, const char *name,
 774                           void *private, const struct rpc_pipe_ops *ops,
 775                           int flags)
 776 {
 777         struct dentry *dentry;
 778         struct inode *dir = parent->d_inode;
 779         umode_t umode = S_IFIFO | S_IRUSR | S_IWUSR;
 780         struct qstr q;
 781         int err;
 782
 783         if (ops->upcall == NULL)
 784                 umode &= ~S_IRUGO;
 785         if (ops->downcall == NULL)
 786                 umode &= ~S_IWUGO;
 787
 788         q.name = name;
 789         q.len = strlen(name);
 790         q.hash = full_name_hash(q.name, q.len),
 791
 792         mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
 793         dentry = __rpc_lookup_create(parent, &q);
 794         if (IS_ERR(dentry))
 795                 goto out;
 796         if (dentry->d_inode) {
 797                 struct rpc_inode *rpci = RPC_I(dentry->d_inode);
 798                 if (rpci->private != private ||
 799                                 rpci->ops != ops ||
 800                                 rpci->flags != flags) {
 801                         dput (dentry);
 802                         err = -EBUSY;
 803                         goto out_err;
 804                 }
 805                 rpci->nkern_readwriters++;
 806                 goto out;
 807         }
 808
 809         err = __rpc_mkpipe(dir, dentry, umode, &rpc_pipe_fops,
 810                            private, ops, flags);
 811         if (err)
 812                 goto out_err;
 813 out:
 814         mutex_unlock(&dir->i_mutex);
 815         return dentry;
 816 out_err:
 817         dentry = ERR_PTR(err);
 818         printk(KERN_WARNING "%s: %s() failed to create pipe %s/%s (errno = %d)\n",
 819                         __FILE__, __func__, parent->d_name.name, name,
 820                         err);
 821         goto out;
 822 }
 823 EXPORT_SYMBOL_GPL(rpc_mkpipe);
 824
 825 /**
 826  * rpc_unlink - remove a pipe
 827  * @dentry: dentry for the pipe, as returned from rpc_mkpipe
 828  *
 829  * After this call, lookups will no longer find the pipe, and any
 830  * attempts to read or write using preexisting opens of the pipe will
 831  * return -EPIPE.
 832  */
 833 int
 834 rpc_unlink(struct dentry *dentry)
 835 {
 836         struct dentry *parent;
 837         struct inode *dir;
 838         int error = 0;
 839
 840         parent = dget_parent(dentry);
 841         dir = parent->d_inode;
 842         mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
 843         error = __rpc_rmpipe(dir, dentry);
 844         mutex_unlock(&dir->i_mutex);
 845         dput(parent);
 846         return error;
 847 }
 848 EXPORT_SYMBOL_GPL(rpc_unlink);
 849
 850 enum {
 851         RPCAUTH_info,
 852         RPCAUTH_EOF
 853 };
 854
 855 static const struct rpc_filelist authfiles[] = {
 856         [RPCAUTH_info] = {
 857                 .name = "info",
 858                 .i_fop = &rpc_info_operations,
 859                 .mode = S_IFREG | S_IRUSR,
 860         },
 861 };
 862
 863 static int rpc_clntdir_populate(struct dentry *dentry, void *private)
 864 {
 865         return rpc_populate(dentry,
 866                             authfiles, RPCAUTH_info, RPCAUTH_EOF,
 867                             private);
 868 }
 869
 870 static void rpc_clntdir_depopulate(struct dentry *dentry)
 871 {
 872         rpc_depopulate(dentry, authfiles, RPCAUTH_info, RPCAUTH_EOF);
 873 }
 874
 875 /**
 876  * rpc_create_client_dir - Create a new rpc_client directory in rpc_pipefs
 877  * @dentry: dentry from the rpc_pipefs root to the new directory
 878  * @name: &struct qstr for the name
 879  * @rpc_client: rpc client to associate with this directory
 880  *
 881  * This creates a directory at the given @path associated with
 882  * @rpc_clnt, which will contain a file named "info" with some basic
 883  * information about the client, together with any "pipes" that may
 884  * later be created using rpc_mkpipe().
 885  */
 886 struct dentry *rpc_create_client_dir(struct dentry *dentry,
 887                                    struct qstr *name,
 888                                    struct rpc_clnt *rpc_client)
 889 {
 890         return rpc_mkdir_populate(dentry, name, S_IRUGO | S_IXUGO, NULL,
 891                         rpc_clntdir_populate, rpc_client);
 892 }
 893
 894 /**
 895  * rpc_remove_client_dir - Remove a directory created with rpc_create_client_dir()
 896  * @dentry: directory to remove
 897  */
 898 int rpc_remove_client_dir(struct dentry *dentry)
 899 {
 900         return rpc_rmdir_depopulate(dentry, rpc_clntdir_depopulate);
 901 }
 902
 903 static const struct rpc_filelist cache_pipefs_files[3] = {
 904         [0] = {
 905                 .name = "channel",
 906                 .i_fop = &cache_file_operations_pipefs,
 907                 .mode = S_IFREG|S_IRUSR|S_IWUSR,
 908         },
 909         [1] = {
 910                 .name = "content",
 911                 .i_fop = &content_file_operations_pipefs,
 912                 .mode = S_IFREG|S_IRUSR,
 913         },
 914         [2] = {
 915                 .name = "flush",
 916                 .i_fop = &cache_flush_operations_pipefs,
 917                 .mode = S_IFREG|S_IRUSR|S_IWUSR,
 918         },
 919 };
 920
 921 static int rpc_cachedir_populate(struct dentry *dentry, void *private)
 922 {
 923         return rpc_populate(dentry,
 924                             cache_pipefs_files, 0, 3,
 925                             private);
 926 }
 927
 928 static void rpc_cachedir_depopulate(struct dentry *dentry)
 929 {
 930         rpc_depopulate(dentry, cache_pipefs_files, 0, 3);
 931 }
 932
 933 struct dentry *rpc_create_cache_dir(struct dentry *parent, struct qstr *name,
 934                                     mode_t umode, struct cache_detail *cd)
 935 {
 936         return rpc_mkdir_populate(parent, name, umode, NULL,
 937                         rpc_cachedir_populate, cd);
 938 }
 939
 940 void rpc_remove_cache_dir(struct dentry *dentry)
 941 {
 942         rpc_rmdir_depopulate(dentry, rpc_cachedir_depopulate);
 943 }
 944
 945 /*
 946  * populate the filesystem
 947  */
 948 static const struct super_operations s_ops = {
 949         .alloc_inode    = rpc_alloc_inode,
 950         .destroy_inode  = rpc_destroy_inode,
 951         .statfs         = simple_statfs,
 952 };
 953
 954 #define RPCAUTH_GSSMAGIC 0x67596969
 955
 956 /*
 957  * We have a single directory with 1 node in it.
 958  */
 959 enum {
 960         RPCAUTH_lockd,
 961         RPCAUTH_mount,
 962         RPCAUTH_nfs,
 963         RPCAUTH_portmap,
 964         RPCAUTH_statd,
 965         RPCAUTH_nfsd4_cb,
 966         RPCAUTH_cache,
 967         RPCAUTH_RootEOF
 968 };
 969
 970 static const struct rpc_filelist files[] = {
 971         [RPCAUTH_lockd] = {
 972                 .name = "lockd",
 973                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
 974         },
 975         [RPCAUTH_mount] = {
 976                 .name = "mount",
 977                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
 978         },
 979         [RPCAUTH_nfs] = {
 980                 .name = "nfs",
 981                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
 982         },
 983         [RPCAUTH_portmap] = {
 984                 .name = "portmap",
 985                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
 986         },
 987         [RPCAUTH_statd] = {
 988                 .name = "statd",
 989                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
 990         },
 991         [RPCAUTH_nfsd4_cb] = {
 992                 .name = "nfsd4_cb",
 993                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
 994         },
 995         [RPCAUTH_cache] = {
 996                 .name = "cache",
 997                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
 998         },
 999 };
1000
1001 static int
1002 rpc_fill_super(struct super_block *sb, void *data, int silent)
1003 {
1004         struct inode *inode;
1005         struct dentry *root;
1006
1007         sb->s_blocksize = PAGE_CACHE_SIZE;
1008         sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
1009         sb->s_magic = RPCAUTH_GSSMAGIC;
1010         sb->s_op = &s_ops;
1011         sb->s_time_gran = 1;
1012
1013         inode = rpc_get_inode(sb, S_IFDIR | 0755);
1014         if (!inode)
1015                 return -ENOMEM;
1016         sb->s_root = root = d_alloc_root(inode);
1017         if (!root) {
1018                 iput(inode);
1019                 return -ENOMEM;
1020         }
1021         if (rpc_populate(root, files, RPCAUTH_lockd, RPCAUTH_RootEOF, NULL))
1022                 return -ENOMEM;
1023         return 0;
1024 }
1025
1026 static int
1027 rpc_get_sb(struct file_system_type *fs_type,
1028                 int flags, const char *dev_name, void *data, struct vfsmount *mnt)
1029 {
1030         return get_sb_single(fs_type, flags, data, rpc_fill_super, mnt);
1031 }
1032
1033 static struct file_system_type rpc_pipe_fs_type = {
1034         .owner          = THIS_MODULE,
1035         .name           = "rpc_pipefs",
1036         .get_sb         = rpc_get_sb,
1037         .kill_sb        = kill_litter_super,
1038 };
1039
1040 static void
1041 init_once(void *foo)
1042 {
1043         struct rpc_inode *rpci = (struct rpc_inode *) foo;
1044
1045         inode_init_once(&rpci->vfs_inode);
1046         rpci->private = NULL;
1047         rpci->nreaders = 0;
1048         rpci->nwriters = 0;
1049         INIT_LIST_HEAD(&rpci->in_upcall);
1050         INIT_LIST_HEAD(&rpci->in_downcall);
1051         INIT_LIST_HEAD(&rpci->pipe);
1052         rpci->pipelen = 0;
1053         init_waitqueue_head(&rpci->waitq);
1054         INIT_DELAYED_WORK(&rpci->queue_timeout,
1055                             rpc_timeout_upcall_queue);
1056         rpci->ops = NULL;
1057 }
1058
1059 int register_rpc_pipefs(void)
1060 {
1061         int err;
1062
1063         rpc_inode_cachep = kmem_cache_create("rpc_inode_cache",
1064                                 sizeof(struct rpc_inode),
1065                                 0, (SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT|
1066                                                 SLAB_MEM_SPREAD),
1067                                 init_once);
1068         if (!rpc_inode_cachep)
1069                 return -ENOMEM;
1070         err = register_filesystem(&rpc_pipe_fs_type);
1071         if (err) {
1072                 kmem_cache_destroy(rpc_inode_cachep);
1073                 return err;
1074         }
1075
1076         return 0;
1077 }
1078
1079 void unregister_rpc_pipefs(void)
1080 {
1081         kmem_cache_destroy(rpc_inode_cachep);
1082         unregister_filesystem(&rpc_pipe_fs_type);
1083 }