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(&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 = (struct rpc_pipe_msg *)filp->private_data;
 207         if (msg != NULL) {
 208                 spin_lock(&inode->i_lock);
 209                 msg->errno = -EAGAIN;
 210                 list_del(&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(&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 int
 312 rpc_pipe_ioctl(struct inode *ino, struct file *filp,
 313                 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 const struct file_operations rpc_pipe_fops = {
 335         .owner          = THIS_MODULE,
 336         .llseek         = no_llseek,
 337         .read           = rpc_pipe_read,
 338         .write          = rpc_pipe_write,
 339         .poll           = rpc_pipe_poll,
 340         .ioctl          = rpc_pipe_ioctl,
 341         .open           = rpc_pipe_open,
 342         .release        = rpc_pipe_release,
 343 };
 344
 345 static int
 346 rpc_show_info(struct seq_file *m, void *v)
 347 {
 348         struct rpc_clnt *clnt = m->private;
 349
 350         seq_printf(m, "RPC server: %s\n", clnt->cl_server);
 351         seq_printf(m, "service: %s (%d) version %d\n", clnt->cl_protname,
 352                         clnt->cl_prog, clnt->cl_vers);
 353         seq_printf(m, "address: %s\n", rpc_peeraddr2str(clnt, RPC_DISPLAY_ADDR));
 354         seq_printf(m, "protocol: %s\n", rpc_peeraddr2str(clnt, RPC_DISPLAY_PROTO));
 355         seq_printf(m, "port: %s\n", rpc_peeraddr2str(clnt, RPC_DISPLAY_PORT));
 356         return 0;
 357 }
 358
 359 static int
 360 rpc_info_open(struct inode *inode, struct file *file)
 361 {
 362         struct rpc_clnt *clnt;
 363         int ret = single_open(file, rpc_show_info, NULL);
 364
 365         if (!ret) {
 366                 struct seq_file *m = file->private_data;
 367                 mutex_lock(&inode->i_mutex);
 368                 clnt = RPC_I(inode)->private;
 369                 if (clnt) {
 370                         kref_get(&clnt->cl_kref);
 371                         m->private = clnt;
 372                 } else {
 373                         single_release(inode, file);
 374                         ret = -EINVAL;
 375                 }
 376                 mutex_unlock(&inode->i_mutex);
 377         }
 378         return ret;
 379 }
 380
 381 static int
 382 rpc_info_release(struct inode *inode, struct file *file)
 383 {
 384         struct seq_file *m = file->private_data;
 385         struct rpc_clnt *clnt = (struct rpc_clnt *)m->private;
 386
 387         if (clnt)
 388                 rpc_release_client(clnt);
 389         return single_release(inode, file);
 390 }
 391
 392 static const struct file_operations rpc_info_operations = {
 393         .owner          = THIS_MODULE,
 394         .open           = rpc_info_open,
 395         .read           = seq_read,
 396         .llseek         = seq_lseek,
 397         .release        = rpc_info_release,
 398 };
 399
 400
 401 /*
 402  * Description of fs contents.
 403  */
 404 struct rpc_filelist {
 405         const char *name;
 406         const struct file_operations *i_fop;
 407         umode_t mode;
 408 };
 409
 410 struct vfsmount *rpc_get_mount(void)
 411 {
 412         int err;
 413
 414         err = simple_pin_fs(&rpc_pipe_fs_type, &rpc_mount, &rpc_mount_count);
 415         if (err != 0)
 416                 return ERR_PTR(err);
 417         return rpc_mount;
 418 }
 419 EXPORT_SYMBOL_GPL(rpc_get_mount);
 420
 421 void rpc_put_mount(void)
 422 {
 423         simple_release_fs(&rpc_mount, &rpc_mount_count);
 424 }
 425 EXPORT_SYMBOL_GPL(rpc_put_mount);
 426
 427 static int rpc_delete_dentry(struct dentry *dentry)
 428 {
 429         return 1;
 430 }
 431
 432 static const struct dentry_operations rpc_dentry_operations = {
 433         .d_delete = rpc_delete_dentry,
 434 };
 435
 436 static struct inode *
 437 rpc_get_inode(struct super_block *sb, umode_t mode)
 438 {
 439         struct inode *inode = new_inode(sb);
 440         if (!inode)
 441                 return NULL;
 442         inode->i_mode = mode;
 443         inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
 444         switch(mode & S_IFMT) {
 445                 case S_IFDIR:
 446                         inode->i_fop = &simple_dir_operations;
 447                         inode->i_op = &simple_dir_inode_operations;
 448                         inc_nlink(inode);
 449                 default:
 450                         break;
 451         }
 452         return inode;
 453 }
 454
 455 static int __rpc_create_common(struct inode *dir, struct dentry *dentry,
 456                                umode_t mode,
 457                                const struct file_operations *i_fop,
 458                                void *private)
 459 {
 460         struct inode *inode;
 461
 462         BUG_ON(!d_unhashed(dentry));
 463         inode = rpc_get_inode(dir->i_sb, mode);
 464         if (!inode)
 465                 goto out_err;
 466         inode->i_ino = iunique(dir->i_sb, 100);
 467         if (i_fop)
 468                 inode->i_fop = i_fop;
 469         if (private)
 470                 rpc_inode_setowner(inode, private);
 471         d_add(dentry, inode);
 472         return 0;
 473 out_err:
 474         printk(KERN_WARNING "%s: %s failed to allocate inode for dentry %s\n",
 475                         __FILE__, __func__, dentry->d_name.name);
 476         dput(dentry);
 477         return -ENOMEM;
 478 }
 479
 480 static int __rpc_create(struct inode *dir, struct dentry *dentry,
 481                         umode_t mode,
 482                         const struct file_operations *i_fop,
 483                         void *private)
 484 {
 485         int err;
 486
 487         err = __rpc_create_common(dir, dentry, S_IFREG | mode, i_fop, private);
 488         if (err)
 489                 return err;
 490         fsnotify_create(dir, dentry);
 491         return 0;
 492 }
 493
 494 static int __rpc_mkdir(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_IFDIR | mode, i_fop, private);
 502         if (err)
 503                 return err;
 504         inc_nlink(dir);
 505         fsnotify_mkdir(dir, dentry);
 506         return 0;
 507 }
 508
 509 static int __rpc_mkpipe(struct inode *dir, struct dentry *dentry,
 510                         umode_t mode,
 511                         const struct file_operations *i_fop,
 512                         void *private,
 513                         const struct rpc_pipe_ops *ops,
 514                         int flags)
 515 {
 516         struct rpc_inode *rpci;
 517         int err;
 518
 519         err = __rpc_create_common(dir, dentry, S_IFIFO | mode, i_fop, private);
 520         if (err)
 521                 return err;
 522         rpci = RPC_I(dentry->d_inode);
 523         rpci->nkern_readwriters = 1;
 524         rpci->private = private;
 525         rpci->flags = flags;
 526         rpci->ops = ops;
 527         fsnotify_create(dir, dentry);
 528         return 0;
 529 }
 530
 531 static int __rpc_rmdir(struct inode *dir, struct dentry *dentry)
 532 {
 533         int ret;
 534
 535         dget(dentry);
 536         ret = simple_rmdir(dir, dentry);
 537         d_delete(dentry);
 538         dput(dentry);
 539         return ret;
 540 }
 541
 542 static int __rpc_unlink(struct inode *dir, struct dentry *dentry)
 543 {
 544         int ret;
 545
 546         dget(dentry);
 547         ret = simple_unlink(dir, dentry);
 548         d_delete(dentry);
 549         dput(dentry);
 550         return ret;
 551 }
 552
 553 static int __rpc_rmpipe(struct inode *dir, struct dentry *dentry)
 554 {
 555         struct inode *inode = dentry->d_inode;
 556         struct rpc_inode *rpci = RPC_I(inode);
 557
 558         rpci->nkern_readwriters--;
 559         if (rpci->nkern_readwriters != 0)
 560                 return 0;
 561         rpc_close_pipes(inode);
 562         return __rpc_unlink(dir, dentry);
 563 }
 564
 565 static struct dentry *__rpc_lookup_create(struct dentry *parent,
 566                                           struct qstr *name)
 567 {
 568         struct dentry *dentry;
 569
 570         dentry = d_lookup(parent, name);
 571         if (!dentry) {
 572                 dentry = d_alloc(parent, name);
 573                 if (!dentry) {
 574                         dentry = ERR_PTR(-ENOMEM);
 575                         goto out_err;
 576                 }
 577         }
 578         if (!dentry->d_inode)
 579                 dentry->d_op = &rpc_dentry_operations;
 580 out_err:
 581         return dentry;
 582 }
 583
 584 static struct dentry *__rpc_lookup_create_exclusive(struct dentry *parent,
 585                                           struct qstr *name)
 586 {
 587         struct dentry *dentry;
 588
 589         dentry = __rpc_lookup_create(parent, name);
 590         if (IS_ERR(dentry))
 591                 return dentry;
 592         if (dentry->d_inode == NULL)
 593                 return dentry;
 594         dput(dentry);
 595         return ERR_PTR(-EEXIST);
 596 }
 597
 598 /*
 599  * FIXME: This probably has races.
 600  */
 601 static void __rpc_depopulate(struct dentry *parent,
 602                              const struct rpc_filelist *files,
 603                              int start, int eof)
 604 {
 605         struct inode *dir = parent->d_inode;
 606         struct dentry *dentry;
 607         struct qstr name;
 608         int i;
 609
 610         for (i = start; i < eof; i++) {
 611                 name.name = files[i].name;
 612                 name.len = strlen(files[i].name);
 613                 name.hash = full_name_hash(name.name, name.len);
 614                 dentry = d_lookup(parent, &name);
 615
 616                 if (dentry == NULL)
 617                         continue;
 618                 if (dentry->d_inode == NULL)
 619                         goto next;
 620                 switch (dentry->d_inode->i_mode & S_IFMT) {
 621                         default:
 622                                 BUG();
 623                         case S_IFREG:
 624                                 __rpc_unlink(dir, dentry);
 625                                 break;
 626                         case S_IFDIR:
 627                                 __rpc_rmdir(dir, dentry);
 628                 }
 629 next:
 630                 dput(dentry);
 631         }
 632 }
 633
 634 static void rpc_depopulate(struct dentry *parent,
 635                            const struct rpc_filelist *files,
 636                            int start, int eof)
 637 {
 638         struct inode *dir = parent->d_inode;
 639
 640         mutex_lock_nested(&dir->i_mutex, I_MUTEX_CHILD);
 641         __rpc_depopulate(parent, files, start, eof);
 642         mutex_unlock(&dir->i_mutex);
 643 }
 644
 645 static int rpc_populate(struct dentry *parent,
 646                         const struct rpc_filelist *files,
 647                         int start, int eof,
 648                         void *private)
 649 {
 650         struct inode *dir = parent->d_inode;
 651         struct dentry *dentry;
 652         int i, err;
 653
 654         mutex_lock(&dir->i_mutex);
 655         for (i = start; i < eof; i++) {
 656                 struct qstr q;
 657
 658                 q.name = files[i].name;
 659                 q.len = strlen(files[i].name);
 660                 q.hash = full_name_hash(q.name, q.len);
 661                 dentry = __rpc_lookup_create_exclusive(parent, &q);
 662                 err = PTR_ERR(dentry);
 663                 if (IS_ERR(dentry))
 664                         goto out_bad;
 665                 switch (files[i].mode & S_IFMT) {
 666                         default:
 667                                 BUG();
 668                         case S_IFREG:
 669                                 err = __rpc_create(dir, dentry,
 670                                                 files[i].mode,
 671                                                 files[i].i_fop,
 672                                                 private);
 673                                 break;
 674                         case S_IFDIR:
 675                                 err = __rpc_mkdir(dir, dentry,
 676                                                 files[i].mode,
 677                                                 NULL,
 678                                                 private);
 679                 }
 680                 if (err != 0)
 681                         goto out_bad;
 682         }
 683         mutex_unlock(&dir->i_mutex);
 684         return 0;
 685 out_bad:
 686         __rpc_depopulate(parent, files, start, eof);
 687         mutex_unlock(&dir->i_mutex);
 688         printk(KERN_WARNING "%s: %s failed to populate directory %s\n",
 689                         __FILE__, __func__, parent->d_name.name);
 690         return err;
 691 }
 692
 693 static struct dentry *rpc_mkdir_populate(struct dentry *parent,
 694                 struct qstr *name, umode_t mode, void *private,
 695                 int (*populate)(struct dentry *, void *), void *args_populate)
 696 {
 697         struct dentry *dentry;
 698         struct inode *dir = parent->d_inode;
 699         int error;
 700
 701         mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
 702         dentry = __rpc_lookup_create_exclusive(parent, name);
 703         if (IS_ERR(dentry))
 704                 goto out;
 705         error = __rpc_mkdir(dir, dentry, mode, NULL, private);
 706         if (error != 0)
 707                 goto out_err;
 708         if (populate != NULL) {
 709                 error = populate(dentry, args_populate);
 710                 if (error)
 711                         goto err_rmdir;
 712         }
 713 out:
 714         mutex_unlock(&dir->i_mutex);
 715         return dentry;
 716 err_rmdir:
 717         __rpc_rmdir(dir, dentry);
 718 out_err:
 719         dentry = ERR_PTR(error);
 720         goto out;
 721 }
 722
 723 static int rpc_rmdir_depopulate(struct dentry *dentry,
 724                 void (*depopulate)(struct dentry *))
 725 {
 726         struct dentry *parent;
 727         struct inode *dir;
 728         int error;
 729
 730         parent = dget_parent(dentry);
 731         dir = parent->d_inode;
 732         mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
 733         if (depopulate != NULL)
 734                 depopulate(dentry);
 735         error = __rpc_rmdir(dir, dentry);
 736         mutex_unlock(&dir->i_mutex);
 737         dput(parent);
 738         return error;
 739 }
 740
 741 /**
 742  * rpc_mkpipe - make an rpc_pipefs file for kernel<->userspace communication
 743  * @parent: dentry of directory to create new "pipe" in
 744  * @name: name of pipe
 745  * @private: private data to associate with the pipe, for the caller's use
 746  * @ops: operations defining the behavior of the pipe: upcall, downcall,
 747  *      release_pipe, open_pipe, and destroy_msg.
 748  * @flags: rpc_inode flags
 749  *
 750  * Data is made available for userspace to read by calls to
 751  * rpc_queue_upcall().  The actual reads will result in calls to
 752  * @ops->upcall, which will be called with the file pointer,
 753  * message, and userspace buffer to copy to.
 754  *
 755  * Writes can come at any time, and do not necessarily have to be
 756  * responses to upcalls.  They will result in calls to @msg->downcall.
 757  *
 758  * The @private argument passed here will be available to all these methods
 759  * from the file pointer, via RPC_I(file->f_dentry->d_inode)->private.
 760  */
 761 struct dentry *rpc_mkpipe(struct dentry *parent, const char *name,
 762                           void *private, const struct rpc_pipe_ops *ops,
 763                           int flags)
 764 {
 765         struct dentry *dentry;
 766         struct inode *dir = parent->d_inode;
 767         umode_t umode = S_IFIFO | S_IRUSR | S_IWUSR;
 768         struct qstr q;
 769         int err;
 770
 771         if (ops->upcall == NULL)
 772                 umode &= ~S_IRUGO;
 773         if (ops->downcall == NULL)
 774                 umode &= ~S_IWUGO;
 775
 776         q.name = name;
 777         q.len = strlen(name);
 778         q.hash = full_name_hash(q.name, q.len),
 779
 780         mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
 781         dentry = __rpc_lookup_create(parent, &q);
 782         if (IS_ERR(dentry))
 783                 goto out;
 784         if (dentry->d_inode) {
 785                 struct rpc_inode *rpci = RPC_I(dentry->d_inode);
 786                 if (rpci->private != private ||
 787                                 rpci->ops != ops ||
 788                                 rpci->flags != flags) {
 789                         dput (dentry);
 790                         err = -EBUSY;
 791                         goto out_err;
 792                 }
 793                 rpci->nkern_readwriters++;
 794                 goto out;
 795         }
 796
 797         err = __rpc_mkpipe(dir, dentry, umode, &rpc_pipe_fops,
 798                            private, ops, flags);
 799         if (err)
 800                 goto out_err;
 801 out:
 802         mutex_unlock(&dir->i_mutex);
 803         return dentry;
 804 out_err:
 805         dentry = ERR_PTR(err);
 806         printk(KERN_WARNING "%s: %s() failed to create pipe %s/%s (errno = %d)\n",
 807                         __FILE__, __func__, parent->d_name.name, name,
 808                         err);
 809         goto out;
 810 }
 811 EXPORT_SYMBOL_GPL(rpc_mkpipe);
 812
 813 /**
 814  * rpc_unlink - remove a pipe
 815  * @dentry: dentry for the pipe, as returned from rpc_mkpipe
 816  *
 817  * After this call, lookups will no longer find the pipe, and any
 818  * attempts to read or write using preexisting opens of the pipe will
 819  * return -EPIPE.
 820  */
 821 int
 822 rpc_unlink(struct dentry *dentry)
 823 {
 824         struct dentry *parent;
 825         struct inode *dir;
 826         int error = 0;
 827
 828         parent = dget_parent(dentry);
 829         dir = parent->d_inode;
 830         mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
 831         error = __rpc_rmpipe(dir, dentry);
 832         mutex_unlock(&dir->i_mutex);
 833         dput(parent);
 834         return error;
 835 }
 836 EXPORT_SYMBOL_GPL(rpc_unlink);
 837
 838 enum {
 839         RPCAUTH_info,
 840         RPCAUTH_EOF
 841 };
 842
 843 static const struct rpc_filelist authfiles[] = {
 844         [RPCAUTH_info] = {
 845                 .name = "info",
 846                 .i_fop = &rpc_info_operations,
 847                 .mode = S_IFREG | S_IRUSR,
 848         },
 849 };
 850
 851 static int rpc_clntdir_populate(struct dentry *dentry, void *private)
 852 {
 853         return rpc_populate(dentry,
 854                             authfiles, RPCAUTH_info, RPCAUTH_EOF,
 855                             private);
 856 }
 857
 858 static void rpc_clntdir_depopulate(struct dentry *dentry)
 859 {
 860         rpc_depopulate(dentry, authfiles, RPCAUTH_info, RPCAUTH_EOF);
 861 }
 862
 863 /**
 864  * rpc_create_client_dir - Create a new rpc_client directory in rpc_pipefs
 865  * @dentry: dentry from the rpc_pipefs root to the new directory
 866  * @name: &struct qstr for the name
 867  * @rpc_client: rpc client to associate with this directory
 868  *
 869  * This creates a directory at the given @path associated with
 870  * @rpc_clnt, which will contain a file named "info" with some basic
 871  * information about the client, together with any "pipes" that may
 872  * later be created using rpc_mkpipe().
 873  */
 874 struct dentry *rpc_create_client_dir(struct dentry *dentry,
 875                                    struct qstr *name,
 876                                    struct rpc_clnt *rpc_client)
 877 {
 878         return rpc_mkdir_populate(dentry, name, S_IRUGO | S_IXUGO, NULL,
 879                         rpc_clntdir_populate, rpc_client);
 880 }
 881
 882 /**
 883  * rpc_remove_client_dir - Remove a directory created with rpc_create_client_dir()
 884  * @dentry: directory to remove
 885  */
 886 int rpc_remove_client_dir(struct dentry *dentry)
 887 {
 888         return rpc_rmdir_depopulate(dentry, rpc_clntdir_depopulate);
 889 }
 890
 891 static const struct rpc_filelist cache_pipefs_files[3] = {
 892         [0] = {
 893                 .name = "channel",
 894                 .i_fop = &cache_file_operations_pipefs,
 895                 .mode = S_IFREG|S_IRUSR|S_IWUSR,
 896         },
 897         [1] = {
 898                 .name = "content",
 899                 .i_fop = &content_file_operations_pipefs,
 900                 .mode = S_IFREG|S_IRUSR,
 901         },
 902         [2] = {
 903                 .name = "flush",
 904                 .i_fop = &cache_flush_operations_pipefs,
 905                 .mode = S_IFREG|S_IRUSR|S_IWUSR,
 906         },
 907 };
 908
 909 static int rpc_cachedir_populate(struct dentry *dentry, void *private)
 910 {
 911         return rpc_populate(dentry,
 912                             cache_pipefs_files, 0, 3,
 913                             private);
 914 }
 915
 916 static void rpc_cachedir_depopulate(struct dentry *dentry)
 917 {
 918         rpc_depopulate(dentry, cache_pipefs_files, 0, 3);
 919 }
 920
 921 struct dentry *rpc_create_cache_dir(struct dentry *parent, struct qstr *name,
 922                                     mode_t umode, struct cache_detail *cd)
 923 {
 924         return rpc_mkdir_populate(parent, name, umode, NULL,
 925                         rpc_cachedir_populate, cd);
 926 }
 927
 928 void rpc_remove_cache_dir(struct dentry *dentry)
 929 {
 930         rpc_rmdir_depopulate(dentry, rpc_cachedir_depopulate);
 931 }
 932
 933 /*
 934  * populate the filesystem
 935  */
 936 static const struct super_operations s_ops = {
 937         .alloc_inode    = rpc_alloc_inode,
 938         .destroy_inode  = rpc_destroy_inode,
 939         .statfs         = simple_statfs,
 940 };
 941
 942 #define RPCAUTH_GSSMAGIC 0x67596969
 943
 944 /*
 945  * We have a single directory with 1 node in it.
 946  */
 947 enum {
 948         RPCAUTH_lockd,
 949         RPCAUTH_mount,
 950         RPCAUTH_nfs,
 951         RPCAUTH_portmap,
 952         RPCAUTH_statd,
 953         RPCAUTH_nfsd4_cb,
 954         RPCAUTH_cache,
 955         RPCAUTH_RootEOF
 956 };
 957
 958 static const struct rpc_filelist files[] = {
 959         [RPCAUTH_lockd] = {
 960                 .name = "lockd",
 961                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
 962         },
 963         [RPCAUTH_mount] = {
 964                 .name = "mount",
 965                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
 966         },
 967         [RPCAUTH_nfs] = {
 968                 .name = "nfs",
 969                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
 970         },
 971         [RPCAUTH_portmap] = {
 972                 .name = "portmap",
 973                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
 974         },
 975         [RPCAUTH_statd] = {
 976                 .name = "statd",
 977                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
 978         },
 979         [RPCAUTH_nfsd4_cb] = {
 980                 .name = "nfsd4_cb",
 981                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
 982         },
 983         [RPCAUTH_cache] = {
 984                 .name = "cache",
 985                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
 986         },
 987 };
 988
 989 static int
 990 rpc_fill_super(struct super_block *sb, void *data, int silent)
 991 {
 992         struct inode *inode;
 993         struct dentry *root;
 994
 995         sb->s_blocksize = PAGE_CACHE_SIZE;
 996         sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
 997         sb->s_magic = RPCAUTH_GSSMAGIC;
 998         sb->s_op = &s_ops;
 999         sb->s_time_gran = 1;
1000
1001         inode = rpc_get_inode(sb, S_IFDIR | 0755);
1002         if (!inode)
1003                 return -ENOMEM;
1004         sb->s_root = root = d_alloc_root(inode);
1005         if (!root) {
1006                 iput(inode);
1007                 return -ENOMEM;
1008         }
1009         if (rpc_populate(root, files, RPCAUTH_lockd, RPCAUTH_RootEOF, NULL))
1010                 return -ENOMEM;
1011         return 0;
1012 }
1013
1014 static int
1015 rpc_get_sb(struct file_system_type *fs_type,
1016                 int flags, const char *dev_name, void *data, struct vfsmount *mnt)
1017 {
1018         return get_sb_single(fs_type, flags, data, rpc_fill_super, mnt);
1019 }
1020
1021 static struct file_system_type rpc_pipe_fs_type = {
1022         .owner          = THIS_MODULE,
1023         .name           = "rpc_pipefs",
1024         .get_sb         = rpc_get_sb,
1025         .kill_sb        = kill_litter_super,
1026 };
1027
1028 static void
1029 init_once(void *foo)
1030 {
1031         struct rpc_inode *rpci = (struct rpc_inode *) foo;
1032
1033         inode_init_once(&rpci->vfs_inode);
1034         rpci->private = NULL;
1035         rpci->nreaders = 0;
1036         rpci->nwriters = 0;
1037         INIT_LIST_HEAD(&rpci->in_upcall);
1038         INIT_LIST_HEAD(&rpci->in_downcall);
1039         INIT_LIST_HEAD(&rpci->pipe);
1040         rpci->pipelen = 0;
1041         init_waitqueue_head(&rpci->waitq);
1042         INIT_DELAYED_WORK(&rpci->queue_timeout,
1043                             rpc_timeout_upcall_queue);
1044         rpci->ops = NULL;
1045 }
1046
1047 int register_rpc_pipefs(void)
1048 {
1049         int err;
1050
1051         rpc_inode_cachep = kmem_cache_create("rpc_inode_cache",
1052                                 sizeof(struct rpc_inode),
1053                                 0, (SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT|
1054                                                 SLAB_MEM_SPREAD),
1055                                 init_once);
1056         if (!rpc_inode_cachep)
1057                 return -ENOMEM;
1058         err = register_filesystem(&rpc_pipe_fs_type);
1059         if (err) {
1060                 kmem_cache_destroy(rpc_inode_cachep);
1061                 return err;
1062         }
1063
1064         return 0;
1065 }
1066
1067 void unregister_rpc_pipefs(void)
1068 {
1069         kmem_cache_destroy(rpc_inode_cachep);
1070         unregister_filesystem(&rpc_pipe_fs_type);
1071 }