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 (dentry->d_inode == NULL)
 591                 return dentry;
 592         dput(dentry);
 593         return ERR_PTR(-EEXIST);
 594 }
 595
 596 /*
 597  * FIXME: This probably has races.
 598  */
 599 static void __rpc_depopulate(struct dentry *parent,
 600                              const struct rpc_filelist *files,
 601                              int start, int eof)
 602 {
 603         struct inode *dir = parent->d_inode;
 604         struct dentry *dentry;
 605         struct qstr name;
 606         int i;
 607
 608         for (i = start; i < eof; i++) {
 609                 name.name = files[i].name;
 610                 name.len = strlen(files[i].name);
 611                 name.hash = full_name_hash(name.name, name.len);
 612                 dentry = d_lookup(parent, &name);
 613
 614                 if (dentry == NULL)
 615                         continue;
 616                 if (dentry->d_inode == NULL)
 617                         goto next;
 618                 switch (dentry->d_inode->i_mode & S_IFMT) {
 619                         default:
 620                                 BUG();
 621                         case S_IFREG:
 622                                 __rpc_unlink(dir, dentry);
 623                                 break;
 624                         case S_IFDIR:
 625                                 __rpc_rmdir(dir, dentry);
 626                 }
 627 next:
 628                 dput(dentry);
 629         }
 630 }
 631
 632 static void rpc_depopulate(struct dentry *parent,
 633                            const struct rpc_filelist *files,
 634                            int start, int eof)
 635 {
 636         struct inode *dir = parent->d_inode;
 637
 638         mutex_lock_nested(&dir->i_mutex, I_MUTEX_CHILD);
 639         __rpc_depopulate(parent, files, start, eof);
 640         mutex_unlock(&dir->i_mutex);
 641 }
 642
 643 static int rpc_populate(struct dentry *parent,
 644                         const struct rpc_filelist *files,
 645                         int start, int eof,
 646                         void *private)
 647 {
 648         struct inode *dir = parent->d_inode;
 649         struct dentry *dentry;
 650         int i, err;
 651
 652         mutex_lock(&dir->i_mutex);
 653         for (i = start; i < eof; i++) {
 654                 struct qstr q;
 655
 656                 q.name = files[i].name;
 657                 q.len = strlen(files[i].name);
 658                 q.hash = full_name_hash(q.name, q.len);
 659                 dentry = __rpc_lookup_create_exclusive(parent, &q);
 660                 err = PTR_ERR(dentry);
 661                 if (IS_ERR(dentry))
 662                         goto out_bad;
 663                 switch (files[i].mode & S_IFMT) {
 664                         default:
 665                                 BUG();
 666                         case S_IFREG:
 667                                 err = __rpc_create(dir, dentry,
 668                                                 files[i].mode,
 669                                                 files[i].i_fop,
 670                                                 private);
 671                                 break;
 672                         case S_IFDIR:
 673                                 err = __rpc_mkdir(dir, dentry,
 674                                                 files[i].mode,
 675                                                 NULL,
 676                                                 private);
 677                 }
 678                 if (err != 0)
 679                         goto out_bad;
 680         }
 681         mutex_unlock(&dir->i_mutex);
 682         return 0;
 683 out_bad:
 684         __rpc_depopulate(parent, files, start, eof);
 685         mutex_unlock(&dir->i_mutex);
 686         printk(KERN_WARNING "%s: %s failed to populate directory %s\n",
 687                         __FILE__, __func__, parent->d_name.name);
 688         return err;
 689 }
 690
 691 static struct dentry *rpc_mkdir_populate(struct dentry *parent,
 692                 struct qstr *name, umode_t mode, void *private,
 693                 int (*populate)(struct dentry *, void *), void *args_populate)
 694 {
 695         struct dentry *dentry;
 696         struct inode *dir = parent->d_inode;
 697         int error;
 698
 699         mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
 700         dentry = __rpc_lookup_create_exclusive(parent, name);
 701         if (IS_ERR(dentry))
 702                 goto out;
 703         error = __rpc_mkdir(dir, dentry, mode, NULL, private);
 704         if (error != 0)
 705                 goto out_err;
 706         if (populate != NULL) {
 707                 error = populate(dentry, args_populate);
 708                 if (error)
 709                         goto err_rmdir;
 710         }
 711 out:
 712         mutex_unlock(&dir->i_mutex);
 713         return dentry;
 714 err_rmdir:
 715         __rpc_rmdir(dir, dentry);
 716 out_err:
 717         dentry = ERR_PTR(error);
 718         goto out;
 719 }
 720
 721 static int rpc_rmdir_depopulate(struct dentry *dentry,
 722                 void (*depopulate)(struct dentry *))
 723 {
 724         struct dentry *parent;
 725         struct inode *dir;
 726         int error;
 727
 728         parent = dget_parent(dentry);
 729         dir = parent->d_inode;
 730         mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
 731         if (depopulate != NULL)
 732                 depopulate(dentry);
 733         error = __rpc_rmdir(dir, dentry);
 734         mutex_unlock(&dir->i_mutex);
 735         dput(parent);
 736         return error;
 737 }
 738
 739 /**
 740  * rpc_mkpipe - make an rpc_pipefs file for kernel<->userspace communication
 741  * @parent: dentry of directory to create new "pipe" in
 742  * @name: name of pipe
 743  * @private: private data to associate with the pipe, for the caller's use
 744  * @ops: operations defining the behavior of the pipe: upcall, downcall,
 745  *      release_pipe, open_pipe, and destroy_msg.
 746  * @flags: rpc_inode flags
 747  *
 748  * Data is made available for userspace to read by calls to
 749  * rpc_queue_upcall().  The actual reads will result in calls to
 750  * @ops->upcall, which will be called with the file pointer,
 751  * message, and userspace buffer to copy to.
 752  *
 753  * Writes can come at any time, and do not necessarily have to be
 754  * responses to upcalls.  They will result in calls to @msg->downcall.
 755  *
 756  * The @private argument passed here will be available to all these methods
 757  * from the file pointer, via RPC_I(file->f_dentry->d_inode)->private.
 758  */
 759 struct dentry *rpc_mkpipe(struct dentry *parent, const char *name,
 760                           void *private, const struct rpc_pipe_ops *ops,
 761                           int flags)
 762 {
 763         struct dentry *dentry;
 764         struct inode *dir = parent->d_inode;
 765         umode_t umode = S_IFIFO | S_IRUSR | S_IWUSR;
 766         struct qstr q;
 767         int err;
 768
 769         if (ops->upcall == NULL)
 770                 umode &= ~S_IRUGO;
 771         if (ops->downcall == NULL)
 772                 umode &= ~S_IWUGO;
 773
 774         q.name = name;
 775         q.len = strlen(name);
 776         q.hash = full_name_hash(q.name, q.len),
 777
 778         mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
 779         dentry = __rpc_lookup_create(parent, &q);
 780         if (IS_ERR(dentry))
 781                 goto out;
 782         if (dentry->d_inode) {
 783                 struct rpc_inode *rpci = RPC_I(dentry->d_inode);
 784                 if (rpci->private != private ||
 785                                 rpci->ops != ops ||
 786                                 rpci->flags != flags) {
 787                         dput (dentry);
 788                         err = -EBUSY;
 789                         goto out_err;
 790                 }
 791                 rpci->nkern_readwriters++;
 792                 goto out;
 793         }
 794
 795         err = __rpc_mkpipe(dir, dentry, umode, &rpc_pipe_fops,
 796                            private, ops, flags);
 797         if (err)
 798                 goto out_err;
 799 out:
 800         mutex_unlock(&dir->i_mutex);
 801         return dentry;
 802 out_err:
 803         dentry = ERR_PTR(err);
 804         printk(KERN_WARNING "%s: %s() failed to create pipe %s/%s (errno = %d)\n",
 805                         __FILE__, __func__, parent->d_name.name, name,
 806                         err);
 807         goto out;
 808 }
 809 EXPORT_SYMBOL_GPL(rpc_mkpipe);
 810
 811 /**
 812  * rpc_unlink - remove a pipe
 813  * @dentry: dentry for the pipe, as returned from rpc_mkpipe
 814  *
 815  * After this call, lookups will no longer find the pipe, and any
 816  * attempts to read or write using preexisting opens of the pipe will
 817  * return -EPIPE.
 818  */
 819 int
 820 rpc_unlink(struct dentry *dentry)
 821 {
 822         struct dentry *parent;
 823         struct inode *dir;
 824         int error = 0;
 825
 826         parent = dget_parent(dentry);
 827         dir = parent->d_inode;
 828         mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
 829         error = __rpc_rmpipe(dir, dentry);
 830         mutex_unlock(&dir->i_mutex);
 831         dput(parent);
 832         return error;
 833 }
 834 EXPORT_SYMBOL_GPL(rpc_unlink);
 835
 836 enum {
 837         RPCAUTH_info,
 838         RPCAUTH_EOF
 839 };
 840
 841 static const struct rpc_filelist authfiles[] = {
 842         [RPCAUTH_info] = {
 843                 .name = "info",
 844                 .i_fop = &rpc_info_operations,
 845                 .mode = S_IFREG | S_IRUSR,
 846         },
 847 };
 848
 849 static int rpc_clntdir_populate(struct dentry *dentry, void *private)
 850 {
 851         return rpc_populate(dentry,
 852                             authfiles, RPCAUTH_info, RPCAUTH_EOF,
 853                             private);
 854 }
 855
 856 static void rpc_clntdir_depopulate(struct dentry *dentry)
 857 {
 858         rpc_depopulate(dentry, authfiles, RPCAUTH_info, RPCAUTH_EOF);
 859 }
 860
 861 /**
 862  * rpc_create_client_dir - Create a new rpc_client directory in rpc_pipefs
 863  * @dentry: dentry from the rpc_pipefs root to the new directory
 864  * @name: &struct qstr for the name
 865  * @rpc_client: rpc client to associate with this directory
 866  *
 867  * This creates a directory at the given @path associated with
 868  * @rpc_clnt, which will contain a file named "info" with some basic
 869  * information about the client, together with any "pipes" that may
 870  * later be created using rpc_mkpipe().
 871  */
 872 struct dentry *rpc_create_client_dir(struct dentry *dentry,
 873                                    struct qstr *name,
 874                                    struct rpc_clnt *rpc_client)
 875 {
 876         return rpc_mkdir_populate(dentry, name, S_IRUGO | S_IXUGO, NULL,
 877                         rpc_clntdir_populate, rpc_client);
 878 }
 879
 880 /**
 881  * rpc_remove_client_dir - Remove a directory created with rpc_create_client_dir()
 882  * @dentry: directory to remove
 883  */
 884 int rpc_remove_client_dir(struct dentry *dentry)
 885 {
 886         return rpc_rmdir_depopulate(dentry, rpc_clntdir_depopulate);
 887 }
 888
 889 static const struct rpc_filelist cache_pipefs_files[3] = {
 890         [0] = {
 891                 .name = "channel",
 892                 .i_fop = &cache_file_operations_pipefs,
 893                 .mode = S_IFREG|S_IRUSR|S_IWUSR,
 894         },
 895         [1] = {
 896                 .name = "content",
 897                 .i_fop = &content_file_operations_pipefs,
 898                 .mode = S_IFREG|S_IRUSR,
 899         },
 900         [2] = {
 901                 .name = "flush",
 902                 .i_fop = &cache_flush_operations_pipefs,
 903                 .mode = S_IFREG|S_IRUSR|S_IWUSR,
 904         },
 905 };
 906
 907 static int rpc_cachedir_populate(struct dentry *dentry, void *private)
 908 {
 909         return rpc_populate(dentry,
 910                             cache_pipefs_files, 0, 3,
 911                             private);
 912 }
 913
 914 static void rpc_cachedir_depopulate(struct dentry *dentry)
 915 {
 916         rpc_depopulate(dentry, cache_pipefs_files, 0, 3);
 917 }
 918
 919 struct dentry *rpc_create_cache_dir(struct dentry *parent, struct qstr *name,
 920                                     mode_t umode, struct cache_detail *cd)
 921 {
 922         return rpc_mkdir_populate(parent, name, umode, NULL,
 923                         rpc_cachedir_populate, cd);
 924 }
 925
 926 void rpc_remove_cache_dir(struct dentry *dentry)
 927 {
 928         rpc_rmdir_depopulate(dentry, rpc_cachedir_depopulate);
 929 }
 930
 931 /*
 932  * populate the filesystem
 933  */
 934 static const struct super_operations s_ops = {
 935         .alloc_inode    = rpc_alloc_inode,
 936         .destroy_inode  = rpc_destroy_inode,
 937         .statfs         = simple_statfs,
 938 };
 939
 940 #define RPCAUTH_GSSMAGIC 0x67596969
 941
 942 /*
 943  * We have a single directory with 1 node in it.
 944  */
 945 enum {
 946         RPCAUTH_lockd,
 947         RPCAUTH_mount,
 948         RPCAUTH_nfs,
 949         RPCAUTH_portmap,
 950         RPCAUTH_statd,
 951         RPCAUTH_nfsd4_cb,
 952         RPCAUTH_cache,
 953         RPCAUTH_RootEOF
 954 };
 955
 956 static const struct rpc_filelist files[] = {
 957         [RPCAUTH_lockd] = {
 958                 .name = "lockd",
 959                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
 960         },
 961         [RPCAUTH_mount] = {
 962                 .name = "mount",
 963                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
 964         },
 965         [RPCAUTH_nfs] = {
 966                 .name = "nfs",
 967                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
 968         },
 969         [RPCAUTH_portmap] = {
 970                 .name = "portmap",
 971                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
 972         },
 973         [RPCAUTH_statd] = {
 974                 .name = "statd",
 975                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
 976         },
 977         [RPCAUTH_nfsd4_cb] = {
 978                 .name = "nfsd4_cb",
 979                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
 980         },
 981         [RPCAUTH_cache] = {
 982                 .name = "cache",
 983                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
 984         },
 985 };
 986
 987 static int
 988 rpc_fill_super(struct super_block *sb, void *data, int silent)
 989 {
 990         struct inode *inode;
 991         struct dentry *root;
 992
 993         sb->s_blocksize = PAGE_CACHE_SIZE;
 994         sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
 995         sb->s_magic = RPCAUTH_GSSMAGIC;
 996         sb->s_op = &s_ops;
 997         sb->s_time_gran = 1;
 998
 999         inode = rpc_get_inode(sb, S_IFDIR | 0755);
1000         if (!inode)
1001                 return -ENOMEM;
1002         sb->s_root = root = d_alloc_root(inode);
1003         if (!root) {
1004                 iput(inode);
1005                 return -ENOMEM;
1006         }
1007         if (rpc_populate(root, files, RPCAUTH_lockd, RPCAUTH_RootEOF, NULL))
1008                 return -ENOMEM;
1009         return 0;
1010 }
1011
1012 static int
1013 rpc_get_sb(struct file_system_type *fs_type,
1014                 int flags, const char *dev_name, void *data, struct vfsmount *mnt)
1015 {
1016         return get_sb_single(fs_type, flags, data, rpc_fill_super, mnt);
1017 }
1018
1019 static struct file_system_type rpc_pipe_fs_type = {
1020         .owner          = THIS_MODULE,
1021         .name           = "rpc_pipefs",
1022         .get_sb         = rpc_get_sb,
1023         .kill_sb        = kill_litter_super,
1024 };
1025
1026 static void
1027 init_once(void *foo)
1028 {
1029         struct rpc_inode *rpci = (struct rpc_inode *) foo;
1030
1031         inode_init_once(&rpci->vfs_inode);
1032         rpci->private = NULL;
1033         rpci->nreaders = 0;
1034         rpci->nwriters = 0;
1035         INIT_LIST_HEAD(&rpci->in_upcall);
1036         INIT_LIST_HEAD(&rpci->in_downcall);
1037         INIT_LIST_HEAD(&rpci->pipe);
1038         rpci->pipelen = 0;
1039         init_waitqueue_head(&rpci->waitq);
1040         INIT_DELAYED_WORK(&rpci->queue_timeout,
1041                             rpc_timeout_upcall_queue);
1042         rpci->ops = NULL;
1043 }
1044
1045 int register_rpc_pipefs(void)
1046 {
1047         int err;
1048
1049         rpc_inode_cachep = kmem_cache_create("rpc_inode_cache",
1050                                 sizeof(struct rpc_inode),
1051                                 0, (SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT|
1052                                                 SLAB_MEM_SPREAD),
1053                                 init_once);
1054         if (!rpc_inode_cachep)
1055                 return -ENOMEM;
1056         err = register_filesystem(&rpc_pipe_fs_type);
1057         if (err) {
1058                 kmem_cache_destroy(rpc_inode_cachep);
1059                 return err;
1060         }
1061
1062         return 0;
1063 }
1064
1065 void unregister_rpc_pipefs(void)
1066 {
1067         kmem_cache_destroy(rpc_inode_cachep);
1068         unregister_filesystem(&rpc_pipe_fs_type);
1069 }