net/sunrpc/rpc_pipe.c

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