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
  30 static struct vfsmount *rpc_mount __read_mostly;
  31 static int rpc_mount_count;
  32
  33 static struct file_system_type rpc_pipe_fs_type;
  34
  35
  36 static struct kmem_cache *rpc_inode_cachep __read_mostly;
  37
  38 #define RPC_UPCALL_TIMEOUT (30*HZ)
  39
  40 static void rpc_purge_list(struct rpc_inode *rpci, struct list_head *head,
  41                 void (*destroy_msg)(struct rpc_pipe_msg *), int err)
  42 {
  43         struct rpc_pipe_msg *msg;
  44
  45         if (list_empty(head))
  46                 return;
  47         do {
  48                 msg = list_entry(head->next, struct rpc_pipe_msg, list);
  49                 list_del(&msg->list);
  50                 msg->errno = err;
  51                 destroy_msg(msg);
  52         } while (!list_empty(head));
  53         wake_up(&rpci->waitq);
  54 }
  55
  56 static void
  57 rpc_timeout_upcall_queue(struct work_struct *work)
  58 {
  59         LIST_HEAD(free_list);
  60         struct rpc_inode *rpci =
  61                 container_of(work, struct rpc_inode, queue_timeout.work);
  62         struct inode *inode = &rpci->vfs_inode;
  63         void (*destroy_msg)(struct rpc_pipe_msg *);
  64
  65         spin_lock(&inode->i_lock);
  66         if (rpci->ops == NULL) {
  67                 spin_unlock(&inode->i_lock);
  68                 return;
  69         }
  70         destroy_msg = rpci->ops->destroy_msg;
  71         if (rpci->nreaders == 0) {
  72                 list_splice_init(&rpci->pipe, &free_list);
  73                 rpci->pipelen = 0;
  74         }
  75         spin_unlock(&inode->i_lock);
  76         rpc_purge_list(rpci, &free_list, destroy_msg, -ETIMEDOUT);
  77 }
  78
  79 /**
  80  * rpc_queue_upcall
  81  * @inode: inode of upcall pipe on which to queue given message
  82  * @msg: message to queue
  83  *
  84  * Call with an @inode created by rpc_mkpipe() to queue an upcall.
  85  * A userspace process may then later read the upcall by performing a
  86  * read on an open file for this inode.  It is up to the caller to
  87  * initialize the fields of @msg (other than @msg->list) appropriately.
  88  */
  89 int
  90 rpc_queue_upcall(struct inode *inode, struct rpc_pipe_msg *msg)
  91 {
  92         struct rpc_inode *rpci = RPC_I(inode);
  93         int res = -EPIPE;
  94
  95         spin_lock(&inode->i_lock);
  96         if (rpci->ops == NULL)
  97                 goto out;
  98         if (rpci->nreaders) {
  99                 list_add_tail(&msg->list, &rpci->pipe);
 100                 rpci->pipelen += msg->len;
 101                 res = 0;
 102         } else if (rpci->flags & RPC_PIPE_WAIT_FOR_OPEN) {
 103                 if (list_empty(&rpci->pipe))
 104                         queue_delayed_work(rpciod_workqueue,
 105                                         &rpci->queue_timeout,
 106                                         RPC_UPCALL_TIMEOUT);
 107                 list_add_tail(&msg->list, &rpci->pipe);
 108                 rpci->pipelen += msg->len;
 109                 res = 0;
 110         }
 111 out:
 112         spin_unlock(&inode->i_lock);
 113         wake_up(&rpci->waitq);
 114         return res;
 115 }
 116 EXPORT_SYMBOL(rpc_queue_upcall);
 117
 118 static inline void
 119 rpc_inode_setowner(struct inode *inode, void *private)
 120 {
 121         RPC_I(inode)->private = private;
 122 }
 123
 124 static void
 125 rpc_close_pipes(struct inode *inode)
 126 {
 127         struct rpc_inode *rpci = RPC_I(inode);
 128         struct rpc_pipe_ops *ops;
 129
 130         mutex_lock(&inode->i_mutex);
 131         ops = rpci->ops;
 132         if (ops != NULL) {
 133                 LIST_HEAD(free_list);
 134
 135                 spin_lock(&inode->i_lock);
 136                 rpci->nreaders = 0;
 137                 list_splice_init(&rpci->in_upcall, &free_list);
 138                 list_splice_init(&rpci->pipe, &free_list);
 139                 rpci->pipelen = 0;
 140                 rpci->ops = NULL;
 141                 spin_unlock(&inode->i_lock);
 142                 rpc_purge_list(rpci, &free_list, ops->destroy_msg, -EPIPE);
 143                 rpci->nwriters = 0;
 144                 if (ops->release_pipe)
 145                         ops->release_pipe(inode);
 146                 cancel_delayed_work_sync(&rpci->queue_timeout);
 147         }
 148         rpc_inode_setowner(inode, NULL);
 149         mutex_unlock(&inode->i_mutex);
 150 }
 151
 152 static struct inode *
 153 rpc_alloc_inode(struct super_block *sb)
 154 {
 155         struct rpc_inode *rpci;
 156         rpci = (struct rpc_inode *)kmem_cache_alloc(rpc_inode_cachep, GFP_KERNEL);
 157         if (!rpci)
 158                 return NULL;
 159         return &rpci->vfs_inode;
 160 }
 161
 162 static void
 163 rpc_destroy_inode(struct inode *inode)
 164 {
 165         kmem_cache_free(rpc_inode_cachep, RPC_I(inode));
 166 }
 167
 168 static int
 169 rpc_pipe_open(struct inode *inode, struct file *filp)
 170 {
 171         struct rpc_inode *rpci = RPC_I(inode);
 172         int res = -ENXIO;
 173
 174         mutex_lock(&inode->i_mutex);
 175         if (rpci->ops != NULL) {
 176                 if (filp->f_mode & FMODE_READ)
 177                         rpci->nreaders ++;
 178                 if (filp->f_mode & FMODE_WRITE)
 179                         rpci->nwriters ++;
 180                 res = 0;
 181         }
 182         mutex_unlock(&inode->i_mutex);
 183         return res;
 184 }
 185
 186 static int
 187 rpc_pipe_release(struct inode *inode, struct file *filp)
 188 {
 189         struct rpc_inode *rpci = RPC_I(inode);
 190         struct rpc_pipe_msg *msg;
 191
 192         mutex_lock(&inode->i_mutex);
 193         if (rpci->ops == NULL)
 194                 goto out;
 195         msg = (struct rpc_pipe_msg *)filp->private_data;
 196         if (msg != NULL) {
 197                 spin_lock(&inode->i_lock);
 198                 msg->errno = -EAGAIN;
 199                 list_del(&msg->list);
 200                 spin_unlock(&inode->i_lock);
 201                 rpci->ops->destroy_msg(msg);
 202         }
 203         if (filp->f_mode & FMODE_WRITE)
 204                 rpci->nwriters --;
 205         if (filp->f_mode & FMODE_READ) {
 206                 rpci->nreaders --;
 207                 if (rpci->nreaders == 0) {
 208                         LIST_HEAD(free_list);
 209                         spin_lock(&inode->i_lock);
 210                         list_splice_init(&rpci->pipe, &free_list);
 211                         rpci->pipelen = 0;
 212                         spin_unlock(&inode->i_lock);
 213                         rpc_purge_list(rpci, &free_list,
 214                                         rpci->ops->destroy_msg, -EAGAIN);
 215                 }
 216         }
 217         if (rpci->ops->release_pipe)
 218                 rpci->ops->release_pipe(inode);
 219 out:
 220         mutex_unlock(&inode->i_mutex);
 221         return 0;
 222 }
 223
 224 static ssize_t
 225 rpc_pipe_read(struct file *filp, char __user *buf, size_t len, loff_t *offset)
 226 {
 227         struct inode *inode = filp->f_path.dentry->d_inode;
 228         struct rpc_inode *rpci = RPC_I(inode);
 229         struct rpc_pipe_msg *msg;
 230         int res = 0;
 231
 232         mutex_lock(&inode->i_mutex);
 233         if (rpci->ops == NULL) {
 234                 res = -EPIPE;
 235                 goto out_unlock;
 236         }
 237         msg = filp->private_data;
 238         if (msg == NULL) {
 239                 spin_lock(&inode->i_lock);
 240                 if (!list_empty(&rpci->pipe)) {
 241                         msg = list_entry(rpci->pipe.next,
 242                                         struct rpc_pipe_msg,
 243                                         list);
 244                         list_move(&msg->list, &rpci->in_upcall);
 245                         rpci->pipelen -= msg->len;
 246                         filp->private_data = msg;
 247                         msg->copied = 0;
 248                 }
 249                 spin_unlock(&inode->i_lock);
 250                 if (msg == NULL)
 251                         goto out_unlock;
 252         }
 253         /* NOTE: it is up to the callback to update msg->copied */
 254         res = rpci->ops->upcall(filp, msg, buf, len);
 255         if (res < 0 || msg->len == msg->copied) {
 256                 filp->private_data = NULL;
 257                 spin_lock(&inode->i_lock);
 258                 list_del(&msg->list);
 259                 spin_unlock(&inode->i_lock);
 260                 rpci->ops->destroy_msg(msg);
 261         }
 262 out_unlock:
 263         mutex_unlock(&inode->i_mutex);
 264         return res;
 265 }
 266
 267 static ssize_t
 268 rpc_pipe_write(struct file *filp, const char __user *buf, size_t len, loff_t *offset)
 269 {
 270         struct inode *inode = filp->f_path.dentry->d_inode;
 271         struct rpc_inode *rpci = RPC_I(inode);
 272         int res;
 273
 274         mutex_lock(&inode->i_mutex);
 275         res = -EPIPE;
 276         if (rpci->ops != NULL)
 277                 res = rpci->ops->downcall(filp, buf, len);
 278         mutex_unlock(&inode->i_mutex);
 279         return res;
 280 }
 281
 282 static unsigned int
 283 rpc_pipe_poll(struct file *filp, struct poll_table_struct *wait)
 284 {
 285         struct rpc_inode *rpci;
 286         unsigned int mask = 0;
 287
 288         rpci = RPC_I(filp->f_path.dentry->d_inode);
 289         poll_wait(filp, &rpci->waitq, wait);
 290
 291         mask = POLLOUT | POLLWRNORM;
 292         if (rpci->ops == NULL)
 293                 mask |= POLLERR | POLLHUP;
 294         if (filp->private_data || !list_empty(&rpci->pipe))
 295                 mask |= POLLIN | POLLRDNORM;
 296         return mask;
 297 }
 298
 299 static int
 300 rpc_pipe_ioctl(struct inode *ino, struct file *filp,
 301                 unsigned int cmd, unsigned long arg)
 302 {
 303         struct rpc_inode *rpci = RPC_I(filp->f_path.dentry->d_inode);
 304         int len;
 305
 306         switch (cmd) {
 307         case FIONREAD:
 308                 if (rpci->ops == NULL)
 309                         return -EPIPE;
 310                 len = rpci->pipelen;
 311                 if (filp->private_data) {
 312                         struct rpc_pipe_msg *msg;
 313                         msg = (struct rpc_pipe_msg *)filp->private_data;
 314                         len += msg->len - msg->copied;
 315                 }
 316                 return put_user(len, (int __user *)arg);
 317         default:
 318                 return -EINVAL;
 319         }
 320 }
 321
 322 static const struct file_operations rpc_pipe_fops = {
 323         .owner          = THIS_MODULE,
 324         .llseek         = no_llseek,
 325         .read           = rpc_pipe_read,
 326         .write          = rpc_pipe_write,
 327         .poll           = rpc_pipe_poll,
 328         .ioctl          = rpc_pipe_ioctl,
 329         .open           = rpc_pipe_open,
 330         .release        = rpc_pipe_release,
 331 };
 332
 333 static int
 334 rpc_show_info(struct seq_file *m, void *v)
 335 {
 336         struct rpc_clnt *clnt = m->private;
 337
 338         seq_printf(m, "RPC server: %s\n", clnt->cl_server);
 339         seq_printf(m, "service: %s (%d) version %d\n", clnt->cl_protname,
 340                         clnt->cl_prog, clnt->cl_vers);
 341         seq_printf(m, "address: %s\n", rpc_peeraddr2str(clnt, RPC_DISPLAY_ADDR));
 342         seq_printf(m, "protocol: %s\n", rpc_peeraddr2str(clnt, RPC_DISPLAY_PROTO));
 343         seq_printf(m, "port: %s\n", rpc_peeraddr2str(clnt, RPC_DISPLAY_PORT));
 344         return 0;
 345 }
 346
 347 static int
 348 rpc_info_open(struct inode *inode, struct file *file)
 349 {
 350         struct rpc_clnt *clnt;
 351         int ret = single_open(file, rpc_show_info, NULL);
 352
 353         if (!ret) {
 354                 struct seq_file *m = file->private_data;
 355                 mutex_lock(&inode->i_mutex);
 356                 clnt = RPC_I(inode)->private;
 357                 if (clnt) {
 358                         kref_get(&clnt->cl_kref);
 359                         m->private = clnt;
 360                 } else {
 361                         single_release(inode, file);
 362                         ret = -EINVAL;
 363                 }
 364                 mutex_unlock(&inode->i_mutex);
 365         }
 366         return ret;
 367 }
 368
 369 static int
 370 rpc_info_release(struct inode *inode, struct file *file)
 371 {
 372         struct seq_file *m = file->private_data;
 373         struct rpc_clnt *clnt = (struct rpc_clnt *)m->private;
 374
 375         if (clnt)
 376                 rpc_release_client(clnt);
 377         return single_release(inode, file);
 378 }
 379
 380 static const struct file_operations rpc_info_operations = {
 381         .owner          = THIS_MODULE,
 382         .open           = rpc_info_open,
 383         .read           = seq_read,
 384         .llseek         = seq_lseek,
 385         .release        = rpc_info_release,
 386 };
 387
 388
 389 /*
 390  * We have a single directory with 1 node in it.
 391  */
 392 enum {
 393         RPCAUTH_Root = 1,
 394         RPCAUTH_lockd,
 395         RPCAUTH_mount,
 396         RPCAUTH_nfs,
 397         RPCAUTH_portmap,
 398         RPCAUTH_statd,
 399         RPCAUTH_RootEOF
 400 };
 401
 402 /*
 403  * Description of fs contents.
 404  */
 405 struct rpc_filelist {
 406         char *name;
 407         const struct file_operations *i_fop;
 408         int mode;
 409 };
 410
 411 static struct rpc_filelist files[] = {
 412         [RPCAUTH_lockd] = {
 413                 .name = "lockd",
 414                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
 415         },
 416         [RPCAUTH_mount] = {
 417                 .name = "mount",
 418                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
 419         },
 420         [RPCAUTH_nfs] = {
 421                 .name = "nfs",
 422                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
 423         },
 424         [RPCAUTH_portmap] = {
 425                 .name = "portmap",
 426                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
 427         },
 428         [RPCAUTH_statd] = {
 429                 .name = "statd",
 430                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
 431         },
 432 };
 433
 434 enum {
 435         RPCAUTH_info = 2,
 436         RPCAUTH_EOF
 437 };
 438
 439 static struct rpc_filelist authfiles[] = {
 440         [RPCAUTH_info] = {
 441                 .name = "info",
 442                 .i_fop = &rpc_info_operations,
 443                 .mode = S_IFREG | S_IRUSR,
 444         },
 445 };
 446
 447 struct vfsmount *rpc_get_mount(void)
 448 {
 449         int err;
 450
 451         err = simple_pin_fs(&rpc_pipe_fs_type, &rpc_mount, &rpc_mount_count);
 452         if (err != 0)
 453                 return ERR_PTR(err);
 454         return rpc_mount;
 455 }
 456
 457 void rpc_put_mount(void)
 458 {
 459         simple_release_fs(&rpc_mount, &rpc_mount_count);
 460 }
 461
 462 static int rpc_delete_dentry(struct dentry *dentry)
 463 {
 464         return 1;
 465 }
 466
 467 static struct dentry_operations rpc_dentry_operations = {
 468         .d_delete = rpc_delete_dentry,
 469 };
 470
 471 static int
 472 rpc_lookup_parent(char *path, struct nameidata *nd)
 473 {
 474         struct vfsmount *mnt;
 475
 476         if (path[0] == '\0')
 477                 return -ENOENT;
 478
 479         mnt = rpc_get_mount();
 480         if (IS_ERR(mnt)) {
 481                 printk(KERN_WARNING "%s: %s failed to mount "
 482                                "pseudofilesystem \n", __FILE__, __FUNCTION__);
 483                 return PTR_ERR(mnt);
 484         }
 485
 486         if (vfs_path_lookup(mnt->mnt_root, mnt, path, LOOKUP_PARENT, nd)) {
 487                 printk(KERN_WARNING "%s: %s failed to find path %s\n",
 488                                 __FILE__, __FUNCTION__, path);
 489                 rpc_put_mount();
 490                 return -ENOENT;
 491         }
 492         return 0;
 493 }
 494
 495 static void
 496 rpc_release_path(struct nameidata *nd)
 497 {
 498         path_put(&nd->path);
 499         rpc_put_mount();
 500 }
 501
 502 static struct inode *
 503 rpc_get_inode(struct super_block *sb, int mode)
 504 {
 505         struct inode *inode = new_inode(sb);
 506         if (!inode)
 507                 return NULL;
 508         inode->i_mode = mode;
 509         inode->i_uid = inode->i_gid = 0;
 510         inode->i_blocks = 0;
 511         inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
 512         switch(mode & S_IFMT) {
 513                 case S_IFDIR:
 514                         inode->i_fop = &simple_dir_operations;
 515                         inode->i_op = &simple_dir_inode_operations;
 516                         inc_nlink(inode);
 517                 default:
 518                         break;
 519         }
 520         return inode;
 521 }
 522
 523 /*
 524  * FIXME: This probably has races.
 525  */
 526 static void rpc_depopulate(struct dentry *parent,
 527                            unsigned long start, unsigned long eof)
 528 {
 529         struct inode *dir = parent->d_inode;
 530         struct list_head *pos, *next;
 531         struct dentry *dentry, *dvec[10];
 532         int n = 0;
 533
 534         mutex_lock_nested(&dir->i_mutex, I_MUTEX_CHILD);
 535 repeat:
 536         spin_lock(&dcache_lock);
 537         list_for_each_safe(pos, next, &parent->d_subdirs) {
 538                 dentry = list_entry(pos, struct dentry, d_u.d_child);
 539                 if (!dentry->d_inode ||
 540                                 dentry->d_inode->i_ino < start ||
 541                                 dentry->d_inode->i_ino >= eof)
 542                         continue;
 543                 spin_lock(&dentry->d_lock);
 544                 if (!d_unhashed(dentry)) {
 545                         dget_locked(dentry);
 546                         __d_drop(dentry);
 547                         spin_unlock(&dentry->d_lock);
 548                         dvec[n++] = dentry;
 549                         if (n == ARRAY_SIZE(dvec))
 550                                 break;
 551                 } else
 552                         spin_unlock(&dentry->d_lock);
 553         }
 554         spin_unlock(&dcache_lock);
 555         if (n) {
 556                 do {
 557                         dentry = dvec[--n];
 558                         if (S_ISREG(dentry->d_inode->i_mode))
 559                                 simple_unlink(dir, dentry);
 560                         else if (S_ISDIR(dentry->d_inode->i_mode))
 561                                 simple_rmdir(dir, dentry);
 562                         d_delete(dentry);
 563                         dput(dentry);
 564                 } while (n);
 565                 goto repeat;
 566         }
 567         mutex_unlock(&dir->i_mutex);
 568 }
 569
 570 static int
 571 rpc_populate(struct dentry *parent,
 572                 struct rpc_filelist *files,
 573                 int start, int eof)
 574 {
 575         struct inode *inode, *dir = parent->d_inode;
 576         void *private = RPC_I(dir)->private;
 577         struct dentry *dentry;
 578         int mode, i;
 579
 580         mutex_lock(&dir->i_mutex);
 581         for (i = start; i < eof; i++) {
 582                 dentry = d_alloc_name(parent, files[i].name);
 583                 if (!dentry)
 584                         goto out_bad;
 585                 dentry->d_op = &rpc_dentry_operations;
 586                 mode = files[i].mode;
 587                 inode = rpc_get_inode(dir->i_sb, mode);
 588                 if (!inode) {
 589                         dput(dentry);
 590                         goto out_bad;
 591                 }
 592                 inode->i_ino = i;
 593                 if (files[i].i_fop)
 594                         inode->i_fop = files[i].i_fop;
 595                 if (private)
 596                         rpc_inode_setowner(inode, private);
 597                 if (S_ISDIR(mode))
 598                         inc_nlink(dir);
 599                 d_add(dentry, inode);
 600                 fsnotify_create(dir, dentry);
 601         }
 602         mutex_unlock(&dir->i_mutex);
 603         return 0;
 604 out_bad:
 605         mutex_unlock(&dir->i_mutex);
 606         printk(KERN_WARNING "%s: %s failed to populate directory %s\n",
 607                         __FILE__, __FUNCTION__, parent->d_name.name);
 608         return -ENOMEM;
 609 }
 610
 611 static int
 612 __rpc_mkdir(struct inode *dir, struct dentry *dentry)
 613 {
 614         struct inode *inode;
 615
 616         inode = rpc_get_inode(dir->i_sb, S_IFDIR | S_IRUGO | S_IXUGO);
 617         if (!inode)
 618                 goto out_err;
 619         inode->i_ino = iunique(dir->i_sb, 100);
 620         d_instantiate(dentry, inode);
 621         inc_nlink(dir);
 622         fsnotify_mkdir(dir, dentry);
 623         return 0;
 624 out_err:
 625         printk(KERN_WARNING "%s: %s failed to allocate inode for dentry %s\n",
 626                         __FILE__, __FUNCTION__, dentry->d_name.name);
 627         return -ENOMEM;
 628 }
 629
 630 static int
 631 __rpc_rmdir(struct inode *dir, struct dentry *dentry)
 632 {
 633         int error;
 634         error = simple_rmdir(dir, dentry);
 635         if (!error)
 636                 d_delete(dentry);
 637         return error;
 638 }
 639
 640 static struct dentry *
 641 rpc_lookup_create(struct dentry *parent, const char *name, int len, int exclusive)
 642 {
 643         struct inode *dir = parent->d_inode;
 644         struct dentry *dentry;
 645
 646         mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
 647         dentry = lookup_one_len(name, parent, len);
 648         if (IS_ERR(dentry))
 649                 goto out_err;
 650         if (!dentry->d_inode)
 651                 dentry->d_op = &rpc_dentry_operations;
 652         else if (exclusive) {
 653                 dput(dentry);
 654                 dentry = ERR_PTR(-EEXIST);
 655                 goto out_err;
 656         }
 657         return dentry;
 658 out_err:
 659         mutex_unlock(&dir->i_mutex);
 660         return dentry;
 661 }
 662
 663 static struct dentry *
 664 rpc_lookup_negative(char *path, struct nameidata *nd)
 665 {
 666         struct dentry *dentry;
 667         int error;
 668
 669         if ((error = rpc_lookup_parent(path, nd)) != 0)
 670                 return ERR_PTR(error);
 671         dentry = rpc_lookup_create(nd->path.dentry, nd->last.name, nd->last.len,
 672                                    1);
 673         if (IS_ERR(dentry))
 674                 rpc_release_path(nd);
 675         return dentry;
 676 }
 677
 678 /**
 679  * rpc_mkdir - Create a new directory in rpc_pipefs
 680  * @path: path from the rpc_pipefs root to the new directory
 681  * @rpc_client: rpc client to associate with this directory
 682  *
 683  * This creates a directory at the given @path associated with
 684  * @rpc_clnt, which will contain a file named "info" with some basic
 685  * information about the client, together with any "pipes" that may
 686  * later be created using rpc_mkpipe().
 687  */
 688 struct dentry *
 689 rpc_mkdir(char *path, struct rpc_clnt *rpc_client)
 690 {
 691         struct nameidata nd;
 692         struct dentry *dentry;
 693         struct inode *dir;
 694         int error;
 695
 696         dentry = rpc_lookup_negative(path, &nd);
 697         if (IS_ERR(dentry))
 698                 return dentry;
 699         dir = nd.path.dentry->d_inode;
 700         if ((error = __rpc_mkdir(dir, dentry)) != 0)
 701                 goto err_dput;
 702         RPC_I(dentry->d_inode)->private = rpc_client;
 703         error = rpc_populate(dentry, authfiles,
 704                         RPCAUTH_info, RPCAUTH_EOF);
 705         if (error)
 706                 goto err_depopulate;
 707         dget(dentry);
 708 out:
 709         mutex_unlock(&dir->i_mutex);
 710         rpc_release_path(&nd);
 711         return dentry;
 712 err_depopulate:
 713         rpc_depopulate(dentry, RPCAUTH_info, RPCAUTH_EOF);
 714         __rpc_rmdir(dir, dentry);
 715 err_dput:
 716         dput(dentry);
 717         printk(KERN_WARNING "%s: %s() failed to create directory %s (errno = %d)\n",
 718                         __FILE__, __FUNCTION__, path, error);
 719         dentry = ERR_PTR(error);
 720         goto out;
 721 }
 722
 723 /**
 724  * rpc_rmdir - Remove a directory created with rpc_mkdir()
 725  * @dentry: directory to remove
 726  */
 727 int
 728 rpc_rmdir(struct dentry *dentry)
 729 {
 730         struct dentry *parent;
 731         struct inode *dir;
 732         int error;
 733
 734         parent = dget_parent(dentry);
 735         dir = parent->d_inode;
 736         mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
 737         rpc_depopulate(dentry, RPCAUTH_info, RPCAUTH_EOF);
 738         error = __rpc_rmdir(dir, dentry);
 739         dput(dentry);
 740         mutex_unlock(&dir->i_mutex);
 741         dput(parent);
 742         return error;
 743 }
 744
 745 /**
 746  * rpc_mkpipe - make an rpc_pipefs file for kernel<->userspace communication
 747  * @parent: dentry of directory to create new "pipe" in
 748  * @name: name of pipe
 749  * @private: private data to associate with the pipe, for the caller's use
 750  * @ops: operations defining the behavior of the pipe: upcall, downcall,
 751  *      release_pipe, and destroy_msg.
 752  * @flags: rpc_inode flags
 753  *
 754  * Data is made available for userspace to read by calls to
 755  * rpc_queue_upcall().  The actual reads will result in calls to
 756  * @ops->upcall, which will be called with the file pointer,
 757  * message, and userspace buffer to copy to.
 758  *
 759  * Writes can come at any time, and do not necessarily have to be
 760  * responses to upcalls.  They will result in calls to @msg->downcall.
 761  *
 762  * The @private argument passed here will be available to all these methods
 763  * from the file pointer, via RPC_I(file->f_dentry->d_inode)->private.
 764  */
 765 struct dentry *
 766 rpc_mkpipe(struct dentry *parent, const char *name, void *private, struct rpc_pipe_ops *ops, int flags)
 767 {
 768         struct dentry *dentry;
 769         struct inode *dir, *inode;
 770         struct rpc_inode *rpci;
 771
 772         dentry = rpc_lookup_create(parent, name, strlen(name), 0);
 773         if (IS_ERR(dentry))
 774                 return dentry;
 775         dir = parent->d_inode;
 776         if (dentry->d_inode) {
 777                 rpci = RPC_I(dentry->d_inode);
 778                 if (rpci->private != private ||
 779                                 rpci->ops != ops ||
 780                                 rpci->flags != flags) {
 781                         dput (dentry);
 782                         dentry = ERR_PTR(-EBUSY);
 783                 }
 784                 rpci->nkern_readwriters++;
 785                 goto out;
 786         }
 787         inode = rpc_get_inode(dir->i_sb, S_IFIFO | S_IRUSR | S_IWUSR);
 788         if (!inode)
 789                 goto err_dput;
 790         inode->i_ino = iunique(dir->i_sb, 100);
 791         inode->i_fop = &rpc_pipe_fops;
 792         d_instantiate(dentry, inode);
 793         rpci = RPC_I(inode);
 794         rpci->private = private;
 795         rpci->flags = flags;
 796         rpci->ops = ops;
 797         rpci->nkern_readwriters = 1;
 798         fsnotify_create(dir, dentry);
 799         dget(dentry);
 800 out:
 801         mutex_unlock(&dir->i_mutex);
 802         return dentry;
 803 err_dput:
 804         dput(dentry);
 805         dentry = ERR_PTR(-ENOMEM);
 806         printk(KERN_WARNING "%s: %s() failed to create pipe %s/%s (errno = %d)\n",
 807                         __FILE__, __FUNCTION__, parent->d_name.name, name,
 808                         -ENOMEM);
 809         goto out;
 810 }
 811 EXPORT_SYMBOL(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         if (--RPC_I(dentry->d_inode)->nkern_readwriters == 0) {
 832                 rpc_close_pipes(dentry->d_inode);
 833                 error = simple_unlink(dir, dentry);
 834                 if (!error)
 835                         d_delete(dentry);
 836         }
 837         dput(dentry);
 838         mutex_unlock(&dir->i_mutex);
 839         dput(parent);
 840         return error;
 841 }
 842 EXPORT_SYMBOL(rpc_unlink);
 843
 844 /*
 845  * populate the filesystem
 846  */
 847 static struct super_operations s_ops = {
 848         .alloc_inode    = rpc_alloc_inode,
 849         .destroy_inode  = rpc_destroy_inode,
 850         .statfs         = simple_statfs,
 851 };
 852
 853 #define RPCAUTH_GSSMAGIC 0x67596969
 854
 855 static int
 856 rpc_fill_super(struct super_block *sb, void *data, int silent)
 857 {
 858         struct inode *inode;
 859         struct dentry *root;
 860
 861         sb->s_blocksize = PAGE_CACHE_SIZE;
 862         sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
 863         sb->s_magic = RPCAUTH_GSSMAGIC;
 864         sb->s_op = &s_ops;
 865         sb->s_time_gran = 1;
 866
 867         inode = rpc_get_inode(sb, S_IFDIR | 0755);
 868         if (!inode)
 869                 return -ENOMEM;
 870         root = d_alloc_root(inode);
 871         if (!root) {
 872                 iput(inode);
 873                 return -ENOMEM;
 874         }
 875         if (rpc_populate(root, files, RPCAUTH_Root + 1, RPCAUTH_RootEOF))
 876                 goto out;
 877         sb->s_root = root;
 878         return 0;
 879 out:
 880         d_genocide(root);
 881         dput(root);
 882         return -ENOMEM;
 883 }
 884
 885 static int
 886 rpc_get_sb(struct file_system_type *fs_type,
 887                 int flags, const char *dev_name, void *data, struct vfsmount *mnt)
 888 {
 889         return get_sb_single(fs_type, flags, data, rpc_fill_super, mnt);
 890 }
 891
 892 static struct file_system_type rpc_pipe_fs_type = {
 893         .owner          = THIS_MODULE,
 894         .name           = "rpc_pipefs",
 895         .get_sb         = rpc_get_sb,
 896         .kill_sb        = kill_litter_super,
 897 };
 898
 899 static void
 900 init_once(struct kmem_cache * cachep, void *foo)
 901 {
 902         struct rpc_inode *rpci = (struct rpc_inode *) foo;
 903
 904         inode_init_once(&rpci->vfs_inode);
 905         rpci->private = NULL;
 906         rpci->nreaders = 0;
 907         rpci->nwriters = 0;
 908         INIT_LIST_HEAD(&rpci->in_upcall);
 909         INIT_LIST_HEAD(&rpci->in_downcall);
 910         INIT_LIST_HEAD(&rpci->pipe);
 911         rpci->pipelen = 0;
 912         init_waitqueue_head(&rpci->waitq);
 913         INIT_DELAYED_WORK(&rpci->queue_timeout,
 914                             rpc_timeout_upcall_queue);
 915         rpci->ops = NULL;
 916 }
 917
 918 int register_rpc_pipefs(void)
 919 {
 920         int err;
 921
 922         rpc_inode_cachep = kmem_cache_create("rpc_inode_cache",
 923                                 sizeof(struct rpc_inode),
 924                                 0, (SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT|
 925                                                 SLAB_MEM_SPREAD),
 926                                 init_once);
 927         if (!rpc_inode_cachep)
 928                 return -ENOMEM;
 929         err = register_filesystem(&rpc_pipe_fs_type);
 930         if (err) {
 931                 kmem_cache_destroy(rpc_inode_cachep);
 932                 return err;
 933         }
 934
 935         return 0;
 936 }
 937
 938 void unregister_rpc_pipefs(void)
 939 {
 940         kmem_cache_destroy(rpc_inode_cachep);
 941         unregister_filesystem(&rpc_pipe_fs_type);
 942 }