SAFE public projects git trees. - safe/jmp/linux-2.6/blob - 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_GPL(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         const struct rpc_pipe_ops *ops;
 129         int need_release;
 130
 131         mutex_lock(&inode->i_mutex);
 132         ops = rpci->ops;
 133         if (ops != NULL) {
 134                 LIST_HEAD(free_list);
 135                 spin_lock(&inode->i_lock);
 136                 need_release = rpci->nreaders != 0 || rpci->nwriters != 0;
 137                 rpci->nreaders = 0;
 138                 list_splice_init(&rpci->in_upcall, &free_list);
 139                 list_splice_init(&rpci->pipe, &free_list);
 140                 rpci->pipelen = 0;
 141                 rpci->ops = NULL;
 142                 spin_unlock(&inode->i_lock);
 143                 rpc_purge_list(rpci, &free_list, ops->destroy_msg, -EPIPE);
 144                 rpci->nwriters = 0;
 145                 if (need_release && ops->release_pipe)
 146                         ops->release_pipe(inode);
 147                 cancel_delayed_work_sync(&rpci->queue_timeout);
 148         }
 149         rpc_inode_setowner(inode, NULL);
 150         mutex_unlock(&inode->i_mutex);
 151 }
 152
 153 static struct inode *
 154 rpc_alloc_inode(struct super_block *sb)
 155 {
 156         struct rpc_inode *rpci;
 157         rpci = (struct rpc_inode *)kmem_cache_alloc(rpc_inode_cachep, GFP_KERNEL);
 158         if (!rpci)
 159                 return NULL;
 160         return &rpci->vfs_inode;
 161 }
 162
 163 static void
 164 rpc_destroy_inode(struct inode *inode)
 165 {
 166         kmem_cache_free(rpc_inode_cachep, RPC_I(inode));
 167 }
 168
 169 static int
 170 rpc_pipe_open(struct inode *inode, struct file *filp)
 171 {
 172         struct rpc_inode *rpci = RPC_I(inode);
 173         int first_open;
 174         int res = -ENXIO;
 175
 176         mutex_lock(&inode->i_mutex);
 177         if (rpci->ops == NULL)
 178                 goto out;
 179         first_open = rpci->nreaders == 0 && rpci->nwriters == 0;
 180         if (first_open && rpci->ops->open_pipe) {
 181                 res = rpci->ops->open_pipe(inode);
 182                 if (res)
 183                         goto out;
 184         }
 185         if (filp->f_mode & FMODE_READ)
 186                 rpci->nreaders++;
 187         if (filp->f_mode & FMODE_WRITE)
 188                 rpci->nwriters++;
 189         res = 0;
 190 out:
 191         mutex_unlock(&inode->i_mutex);
 192         return res;
 193 }
 194
 195 static int
 196 rpc_pipe_release(struct inode *inode, struct file *filp)
 197 {
 198         struct rpc_inode *rpci = RPC_I(inode);
 199         struct rpc_pipe_msg *msg;
 200         int last_close;
 201
 202         mutex_lock(&inode->i_mutex);
 203         if (rpci->ops == NULL)
 204                 goto out;
 205         msg = (struct rpc_pipe_msg *)filp->private_data;
 206         if (msg != NULL) {
 207                 spin_lock(&inode->i_lock);
 208                 msg->errno = -EAGAIN;
 209                 list_del(&msg->list);
 210                 spin_unlock(&inode->i_lock);
 211                 rpci->ops->destroy_msg(msg);
 212         }
 213         if (filp->f_mode & FMODE_WRITE)
 214                 rpci->nwriters --;
 215         if (filp->f_mode & FMODE_READ) {
 216                 rpci->nreaders --;
 217                 if (rpci->nreaders == 0) {
 218                         LIST_HEAD(free_list);
 219                         spin_lock(&inode->i_lock);
 220                         list_splice_init(&rpci->pipe, &free_list);
 221                         rpci->pipelen = 0;
 222                         spin_unlock(&inode->i_lock);
 223                         rpc_purge_list(rpci, &free_list,
 224                                         rpci->ops->destroy_msg, -EAGAIN);
 225                 }
 226         }
 227         last_close = rpci->nwriters == 0 && rpci->nreaders == 0;
 228         if (last_close && rpci->ops->release_pipe)
 229                 rpci->ops->release_pipe(inode);
 230 out:
 231         mutex_unlock(&inode->i_mutex);
 232         return 0;
 233 }
 234
 235 static ssize_t
 236 rpc_pipe_read(struct file *filp, char __user *buf, size_t len, loff_t *offset)
 237 {
 238         struct inode *inode = filp->f_path.dentry->d_inode;
 239         struct rpc_inode *rpci = RPC_I(inode);
 240         struct rpc_pipe_msg *msg;
 241         int res = 0;
 242
 243         mutex_lock(&inode->i_mutex);
 244         if (rpci->ops == NULL) {
 245                 res = -EPIPE;
 246                 goto out_unlock;
 247         }
 248         msg = filp->private_data;
 249         if (msg == NULL) {
 250                 spin_lock(&inode->i_lock);
 251                 if (!list_empty(&rpci->pipe)) {
 252                         msg = list_entry(rpci->pipe.next,
 253                                         struct rpc_pipe_msg,
 254                                         list);
 255                         list_move(&msg->list, &rpci->in_upcall);
 256                         rpci->pipelen -= msg->len;
 257                         filp->private_data = msg;
 258                         msg->copied = 0;
 259                 }
 260                 spin_unlock(&inode->i_lock);
 261                 if (msg == NULL)
 262                         goto out_unlock;
 263         }
 264         /* NOTE: it is up to the callback to update msg->copied */
 265         res = rpci->ops->upcall(filp, msg, buf, len);
 266         if (res < 0 || msg->len == msg->copied) {
 267                 filp->private_data = NULL;
 268                 spin_lock(&inode->i_lock);
 269                 list_del(&msg->list);
 270                 spin_unlock(&inode->i_lock);
 271                 rpci->ops->destroy_msg(msg);
 272         }
 273 out_unlock:
 274         mutex_unlock(&inode->i_mutex);
 275         return res;
 276 }
 277
 278 static ssize_t
 279 rpc_pipe_write(struct file *filp, const char __user *buf, size_t len, loff_t *offset)
 280 {
 281         struct inode *inode = filp->f_path.dentry->d_inode;
 282         struct rpc_inode *rpci = RPC_I(inode);
 283         int res;
 284
 285         mutex_lock(&inode->i_mutex);
 286         res = -EPIPE;
 287         if (rpci->ops != NULL)
 288                 res = rpci->ops->downcall(filp, buf, len);
 289         mutex_unlock(&inode->i_mutex);
 290         return res;
 291 }
 292
 293 static unsigned int
 294 rpc_pipe_poll(struct file *filp, struct poll_table_struct *wait)
 295 {
 296         struct rpc_inode *rpci;
 297         unsigned int mask = 0;
 298
 299         rpci = RPC_I(filp->f_path.dentry->d_inode);
 300         poll_wait(filp, &rpci->waitq, wait);
 301
 302         mask = POLLOUT | POLLWRNORM;
 303         if (rpci->ops == NULL)
 304                 mask |= POLLERR | POLLHUP;
 305         if (filp->private_data || !list_empty(&rpci->pipe))
 306                 mask |= POLLIN | POLLRDNORM;
 307         return mask;
 308 }
 309
 310 static int
 311 rpc_pipe_ioctl(struct inode *ino, struct file *filp,
 312                 unsigned int cmd, unsigned long arg)
 313 {
 314         struct rpc_inode *rpci = RPC_I(filp->f_path.dentry->d_inode);
 315         int len;
 316
 317         switch (cmd) {
 318         case FIONREAD:
 319                 if (rpci->ops == NULL)
 320                         return -EPIPE;
 321                 len = rpci->pipelen;
 322                 if (filp->private_data) {
 323                         struct rpc_pipe_msg *msg;
 324                         msg = (struct rpc_pipe_msg *)filp->private_data;
 325                         len += msg->len - msg->copied;
 326                 }
 327                 return put_user(len, (int __user *)arg);
 328         default:
 329                 return -EINVAL;
 330         }
 331 }
 332
 333 static const struct file_operations rpc_pipe_fops = {
 334         .owner          = THIS_MODULE,
 335         .llseek         = no_llseek,
 336         .read           = rpc_pipe_read,
 337         .write          = rpc_pipe_write,
 338         .poll           = rpc_pipe_poll,
 339         .ioctl          = rpc_pipe_ioctl,
 340         .open           = rpc_pipe_open,
 341         .release        = rpc_pipe_release,
 342 };
 343
 344 static int
 345 rpc_show_info(struct seq_file *m, void *v)
 346 {
 347         struct rpc_clnt *clnt = m->private;
 348
 349         seq_printf(m, "RPC server: %s\n", clnt->cl_server);
 350         seq_printf(m, "service: %s (%d) version %d\n", clnt->cl_protname,
 351                         clnt->cl_prog, clnt->cl_vers);
 352         seq_printf(m, "address: %s\n", rpc_peeraddr2str(clnt, RPC_DISPLAY_ADDR));
 353         seq_printf(m, "protocol: %s\n", rpc_peeraddr2str(clnt, RPC_DISPLAY_PROTO));
 354         seq_printf(m, "port: %s\n", rpc_peeraddr2str(clnt, RPC_DISPLAY_PORT));
 355         return 0;
 356 }
 357
 358 static int
 359 rpc_info_open(struct inode *inode, struct file *file)
 360 {
 361         struct rpc_clnt *clnt;
 362         int ret = single_open(file, rpc_show_info, NULL);
 363
 364         if (!ret) {
 365                 struct seq_file *m = file->private_data;
 366                 mutex_lock(&inode->i_mutex);
 367                 clnt = RPC_I(inode)->private;
 368                 if (clnt) {
 369                         kref_get(&clnt->cl_kref);
 370                         m->private = clnt;
 371                 } else {
 372                         single_release(inode, file);
 373                         ret = -EINVAL;
 374                 }
 375                 mutex_unlock(&inode->i_mutex);
 376         }
 377         return ret;
 378 }
 379
 380 static int
 381 rpc_info_release(struct inode *inode, struct file *file)
 382 {
 383         struct seq_file *m = file->private_data;
 384         struct rpc_clnt *clnt = (struct rpc_clnt *)m->private;
 385
 386         if (clnt)
 387                 rpc_release_client(clnt);
 388         return single_release(inode, file);
 389 }
 390
 391 static const struct file_operations rpc_info_operations = {
 392         .owner          = THIS_MODULE,
 393         .open           = rpc_info_open,
 394         .read           = seq_read,
 395         .llseek         = seq_lseek,
 396         .release        = rpc_info_release,
 397 };
 398
 399
 400 /*
 401  * We have a single directory with 1 node in it.
 402  */
 403 enum {
 404         RPCAUTH_lockd,
 405         RPCAUTH_mount,
 406         RPCAUTH_nfs,
 407         RPCAUTH_portmap,
 408         RPCAUTH_statd,
 409         RPCAUTH_nfsd4_cb,
 410         RPCAUTH_RootEOF
 411 };
 412
 413 /*
 414  * Description of fs contents.
 415  */
 416 struct rpc_filelist {
 417         const char *name;
 418         const struct file_operations *i_fop;
 419         umode_t mode;
 420 };
 421
 422 static const struct rpc_filelist files[] = {
 423         [RPCAUTH_lockd] = {
 424                 .name = "lockd",
 425                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
 426         },
 427         [RPCAUTH_mount] = {
 428                 .name = "mount",
 429                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
 430         },
 431         [RPCAUTH_nfs] = {
 432                 .name = "nfs",
 433                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
 434         },
 435         [RPCAUTH_portmap] = {
 436                 .name = "portmap",
 437                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
 438         },
 439         [RPCAUTH_statd] = {
 440                 .name = "statd",
 441                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
 442         },
 443         [RPCAUTH_nfsd4_cb] = {
 444                 .name = "nfsd4_cb",
 445                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
 446         },
 447 };
 448
 449 enum {
 450         RPCAUTH_info,
 451         RPCAUTH_EOF
 452 };
 453
 454 static const struct rpc_filelist authfiles[] = {
 455         [RPCAUTH_info] = {
 456                 .name = "info",
 457                 .i_fop = &rpc_info_operations,
 458                 .mode = S_IFREG | S_IRUSR,
 459         },
 460 };
 461
 462 struct vfsmount *rpc_get_mount(void)
 463 {
 464         int err;
 465
 466         err = simple_pin_fs(&rpc_pipe_fs_type, &rpc_mount, &rpc_mount_count);
 467         if (err != 0)
 468                 return ERR_PTR(err);
 469         return rpc_mount;
 470 }
 471
 472 void rpc_put_mount(void)
 473 {
 474         simple_release_fs(&rpc_mount, &rpc_mount_count);
 475 }
 476
 477 static int rpc_delete_dentry(struct dentry *dentry)
 478 {
 479         return 1;
 480 }
 481
 482 static const struct dentry_operations rpc_dentry_operations = {
 483         .d_delete = rpc_delete_dentry,
 484 };
 485
 486 static int __rpc_lookup_path(const char *pathname, unsigned flags,
 487                              struct nameidata *nd)
 488 {
 489         struct vfsmount *mnt;
 490
 491         if (pathname[0] == '\0')
 492                 return -ENOENT;
 493
 494         mnt = rpc_get_mount();
 495         if (IS_ERR(mnt)) {
 496                 printk(KERN_WARNING "%s: %s failed to mount "
 497                                "pseudofilesystem \n", __FILE__, __func__);
 498                 return PTR_ERR(mnt);
 499         }
 500
 501         if (vfs_path_lookup(mnt->mnt_root, mnt, pathname, flags, nd)) {
 502                 printk(KERN_WARNING "%s: %s failed to find path %s\n",
 503                                 __FILE__, __func__, pathname);
 504                 rpc_put_mount();
 505                 return -ENOENT;
 506         }
 507         return 0;
 508 }
 509
 510 static int rpc_lookup_parent(const char *pathname, struct nameidata *nd)
 511 {
 512         return __rpc_lookup_path(pathname, LOOKUP_PARENT, nd);
 513 }
 514
 515 static void
 516 rpc_release_path(struct nameidata *nd)
 517 {
 518         path_put(&nd->path);
 519         rpc_put_mount();
 520 }
 521
 522 static struct inode *
 523 rpc_get_inode(struct super_block *sb, umode_t mode)
 524 {
 525         struct inode *inode = new_inode(sb);
 526         if (!inode)
 527                 return NULL;
 528         inode->i_mode = mode;
 529         inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
 530         switch(mode & S_IFMT) {
 531                 case S_IFDIR:
 532                         inode->i_fop = &simple_dir_operations;
 533                         inode->i_op = &simple_dir_inode_operations;
 534                         inc_nlink(inode);
 535                 default:
 536                         break;
 537         }
 538         return inode;
 539 }
 540
 541 static int __rpc_create_common(struct inode *dir, struct dentry *dentry,
 542                                umode_t mode,
 543                                const struct file_operations *i_fop,
 544                                void *private)
 545 {
 546         struct inode *inode;
 547
 548         BUG_ON(!d_unhashed(dentry));
 549         inode = rpc_get_inode(dir->i_sb, mode);
 550         if (!inode)
 551                 goto out_err;
 552         inode->i_ino = iunique(dir->i_sb, 100);
 553         if (i_fop)
 554                 inode->i_fop = i_fop;
 555         if (private)
 556                 rpc_inode_setowner(inode, private);
 557         d_add(dentry, inode);
 558         return 0;
 559 out_err:
 560         printk(KERN_WARNING "%s: %s failed to allocate inode for dentry %s\n",
 561                         __FILE__, __func__, dentry->d_name.name);
 562         dput(dentry);
 563         return -ENOMEM;
 564 }
 565
 566 static int __rpc_create(struct inode *dir, struct dentry *dentry,
 567                         umode_t mode,
 568                         const struct file_operations *i_fop,
 569                         void *private)
 570 {
 571         int err;
 572
 573         err = __rpc_create_common(dir, dentry, S_IFREG | mode, i_fop, private);
 574         if (err)
 575                 return err;
 576         fsnotify_create(dir, dentry);
 577         return 0;
 578 }
 579
 580 static int __rpc_mkdir(struct inode *dir, struct dentry *dentry,
 581                        umode_t mode,
 582                        const struct file_operations *i_fop,
 583                        void *private)
 584 {
 585         int err;
 586
 587         err = __rpc_create_common(dir, dentry, S_IFDIR | mode, i_fop, private);
 588         if (err)
 589                 return err;
 590         inc_nlink(dir);
 591         fsnotify_mkdir(dir, dentry);
 592         return 0;
 593 }
 594
 595 static int __rpc_mkpipe(struct inode *dir, struct dentry *dentry,
 596                         umode_t mode,
 597                         const struct file_operations *i_fop,
 598                         void *private,
 599                         const struct rpc_pipe_ops *ops,
 600                         int flags)
 601 {
 602         struct rpc_inode *rpci;
 603         int err;
 604
 605         err = __rpc_create_common(dir, dentry, S_IFIFO | mode, i_fop, private);
 606         if (err)
 607                 return err;
 608         rpci = RPC_I(dentry->d_inode);
 609         rpci->nkern_readwriters = 1;
 610         rpci->private = private;
 611         rpci->flags = flags;
 612         rpci->ops = ops;
 613         fsnotify_create(dir, dentry);
 614         return 0;
 615 }
 616
 617 static int __rpc_rmdir(struct inode *dir, struct dentry *dentry)
 618 {
 619         int ret;
 620
 621         dget(dentry);
 622         ret = simple_rmdir(dir, dentry);
 623         d_delete(dentry);
 624         dput(dentry);
 625         return ret;
 626 }
 627
 628 static int __rpc_unlink(struct inode *dir, struct dentry *dentry)
 629 {
 630         int ret;
 631
 632         dget(dentry);
 633         ret = simple_unlink(dir, dentry);
 634         d_delete(dentry);
 635         dput(dentry);
 636         return ret;
 637 }
 638
 639 static int __rpc_rmpipe(struct inode *dir, struct dentry *dentry)
 640 {
 641         struct inode *inode = dentry->d_inode;
 642         struct rpc_inode *rpci = RPC_I(inode);
 643
 644         rpci->nkern_readwriters--;
 645         if (rpci->nkern_readwriters != 0)
 646                 return 0;
 647         rpc_close_pipes(inode);
 648         return __rpc_unlink(dir, dentry);
 649 }
 650
 651 static struct dentry *__rpc_lookup_create(struct dentry *parent,
 652                                           struct qstr *name)
 653 {
 654         struct dentry *dentry;
 655
 656         dentry = d_lookup(parent, name);
 657         if (!dentry) {
 658                 dentry = d_alloc(parent, name);
 659                 if (!dentry) {
 660                         dentry = ERR_PTR(-ENOMEM);
 661                         goto out_err;
 662                 }
 663         }
 664         if (!dentry->d_inode)
 665                 dentry->d_op = &rpc_dentry_operations;
 666 out_err:
 667         return dentry;
 668 }
 669
 670 static struct dentry *__rpc_lookup_create_exclusive(struct dentry *parent,
 671                                           struct qstr *name)
 672 {
 673         struct dentry *dentry;
 674
 675         dentry = __rpc_lookup_create(parent, name);
 676         if (dentry->d_inode == NULL)
 677                 return dentry;
 678         dput(dentry);
 679         return ERR_PTR(-EEXIST);
 680 }
 681
 682 static struct dentry *rpc_lookup_negative(const char *path,
 683                                           struct nameidata *nd)
 684 {
 685         struct inode *dir;
 686         struct dentry *dentry;
 687         int error;
 688
 689         error = rpc_lookup_parent(path, nd);
 690         if (error != 0)
 691                 return ERR_PTR(error);
 692         dir = nd->path.dentry->d_inode;
 693         mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
 694         dentry = __rpc_lookup_create_exclusive(nd->path.dentry, &nd->last);
 695         if (IS_ERR(dentry)) {
 696                 mutex_unlock(&dir->i_mutex);
 697                 rpc_release_path(nd);
 698         }
 699         return dentry;
 700 }
 701
 702 /*
 703  * FIXME: This probably has races.
 704  */
 705 static void __rpc_depopulate(struct dentry *parent,
 706                              const struct rpc_filelist *files,
 707                              int start, int eof)
 708 {
 709         struct inode *dir = parent->d_inode;
 710         struct dentry *dentry;
 711         struct qstr name;
 712         int i;
 713
 714         for (i = start; i < eof; i++) {
 715                 name.name = files[i].name;
 716                 name.len = strlen(files[i].name);
 717                 name.hash = full_name_hash(name.name, name.len);
 718                 dentry = d_lookup(parent, &name);
 719
 720                 if (dentry == NULL)
 721                         continue;
 722                 if (dentry->d_inode == NULL)
 723                         goto next;
 724                 switch (dentry->d_inode->i_mode & S_IFMT) {
 725                         default:
 726                                 BUG();
 727                         case S_IFREG:
 728                                 __rpc_unlink(dir, dentry);
 729                                 break;
 730                         case S_IFDIR:
 731                                 __rpc_rmdir(dir, dentry);
 732                 }
 733 next:
 734                 dput(dentry);
 735         }
 736 }
 737
 738 static void rpc_depopulate(struct dentry *parent,
 739                            const struct rpc_filelist *files,
 740                            int start, int eof)
 741 {
 742         struct inode *dir = parent->d_inode;
 743
 744         mutex_lock_nested(&dir->i_mutex, I_MUTEX_CHILD);
 745         __rpc_depopulate(parent, files, start, eof);
 746         mutex_unlock(&dir->i_mutex);
 747 }
 748
 749 static int rpc_populate(struct dentry *parent,
 750                         const struct rpc_filelist *files,
 751                         int start, int eof,
 752                         void *private)
 753 {
 754         struct inode *dir = parent->d_inode;
 755         struct dentry *dentry;
 756         int i, err;
 757
 758         mutex_lock(&dir->i_mutex);
 759         for (i = start; i < eof; i++) {
 760                 struct qstr q;
 761
 762                 q.name = files[i].name;
 763                 q.len = strlen(files[i].name);
 764                 q.hash = full_name_hash(q.name, q.len);
 765                 dentry = __rpc_lookup_create_exclusive(parent, &q);
 766                 err = PTR_ERR(dentry);
 767                 if (IS_ERR(dentry))
 768                         goto out_bad;
 769                 switch (files[i].mode & S_IFMT) {
 770                         default:
 771                                 BUG();
 772                         case S_IFREG:
 773                                 err = __rpc_create(dir, dentry,
 774                                                 files[i].mode,
 775                                                 files[i].i_fop,
 776                                                 private);
 777                                 break;
 778                         case S_IFDIR:
 779                                 err = __rpc_mkdir(dir, dentry,
 780                                                 files[i].mode,
 781                                                 NULL,
 782                                                 private);
 783                 }
 784                 if (err != 0)
 785                         goto out_bad;
 786         }
 787         mutex_unlock(&dir->i_mutex);
 788         return 0;
 789 out_bad:
 790         __rpc_depopulate(parent, files, start, eof);
 791         mutex_unlock(&dir->i_mutex);
 792         printk(KERN_WARNING "%s: %s failed to populate directory %s\n",
 793                         __FILE__, __func__, parent->d_name.name);
 794         return err;
 795 }
 796
 797 /**
 798  * rpc_mkdir - Create a new directory in rpc_pipefs
 799  * @path: path from the rpc_pipefs root to the new directory
 800  * @rpc_client: rpc client to associate with this directory
 801  *
 802  * This creates a directory at the given @path associated with
 803  * @rpc_clnt, which will contain a file named "info" with some basic
 804  * information about the client, together with any "pipes" that may
 805  * later be created using rpc_mkpipe().
 806  */
 807 struct dentry *
 808 rpc_mkdir(char *path, struct rpc_clnt *rpc_client)
 809 {
 810         struct nameidata nd;
 811         struct dentry *dentry;
 812         struct inode *dir;
 813         int error;
 814
 815         dentry = rpc_lookup_negative(path, &nd);
 816         if (IS_ERR(dentry))
 817                 return dentry;
 818         dir = nd.path.dentry->d_inode;
 819         error = __rpc_mkdir(dir, dentry, S_IRUGO | S_IXUGO, NULL, rpc_client);
 820         if (error != 0)
 821                 goto out_err;
 822         error = rpc_populate(dentry, authfiles,
 823                         RPCAUTH_info, RPCAUTH_EOF, rpc_client);
 824         if (error)
 825                 goto err_rmdir;
 826 out:
 827         mutex_unlock(&dir->i_mutex);
 828         rpc_release_path(&nd);
 829         return dentry;
 830 err_rmdir:
 831         __rpc_rmdir(dir, dentry);
 832 out_err:
 833         printk(KERN_WARNING "%s: %s() failed to create directory %s (errno = %d)\n",
 834                         __FILE__, __func__, path, error);
 835         dentry = ERR_PTR(error);
 836         goto out;
 837 }
 838
 839 /**
 840  * rpc_rmdir - Remove a directory created with rpc_mkdir()
 841  * @dentry: directory to remove
 842  */
 843 int
 844 rpc_rmdir(struct dentry *dentry)
 845 {
 846         struct dentry *parent;
 847         struct inode *dir;
 848         int error;
 849
 850         parent = dget_parent(dentry);
 851         dir = parent->d_inode;
 852         mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
 853         rpc_depopulate(dentry, authfiles, RPCAUTH_info, RPCAUTH_EOF);
 854         error = __rpc_rmdir(dir, dentry);
 855         mutex_unlock(&dir->i_mutex);
 856         dput(parent);
 857         return error;
 858 }
 859
 860 /**
 861  * rpc_mkpipe - make an rpc_pipefs file for kernel<->userspace communication
 862  * @parent: dentry of directory to create new "pipe" in
 863  * @name: name of pipe
 864  * @private: private data to associate with the pipe, for the caller's use
 865  * @ops: operations defining the behavior of the pipe: upcall, downcall,
 866  *      release_pipe, open_pipe, and destroy_msg.
 867  * @flags: rpc_inode flags
 868  *
 869  * Data is made available for userspace to read by calls to
 870  * rpc_queue_upcall().  The actual reads will result in calls to
 871  * @ops->upcall, which will be called with the file pointer,
 872  * message, and userspace buffer to copy to.
 873  *
 874  * Writes can come at any time, and do not necessarily have to be
 875  * responses to upcalls.  They will result in calls to @msg->downcall.
 876  *
 877  * The @private argument passed here will be available to all these methods
 878  * from the file pointer, via RPC_I(file->f_dentry->d_inode)->private.
 879  */
 880 struct dentry *rpc_mkpipe(struct dentry *parent, const char *name,
 881                           void *private, const struct rpc_pipe_ops *ops,
 882                           int flags)
 883 {
 884         struct dentry *dentry;
 885         struct inode *dir = parent->d_inode;
 886         umode_t umode = S_IFIFO | S_IRUSR | S_IWUSR;
 887         struct qstr q;
 888         int err;
 889
 890         if (ops->upcall == NULL)
 891                 umode &= ~S_IRUGO;
 892         if (ops->downcall == NULL)
 893                 umode &= ~S_IWUGO;
 894
 895         q.name = name;
 896         q.len = strlen(name);
 897         q.hash = full_name_hash(q.name, q.len),
 898
 899         mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
 900         dentry = __rpc_lookup_create(parent, &q);
 901         if (IS_ERR(dentry))
 902                 goto out;
 903         if (dentry->d_inode) {
 904                 struct rpc_inode *rpci = RPC_I(dentry->d_inode);
 905                 if (rpci->private != private ||
 906                                 rpci->ops != ops ||
 907                                 rpci->flags != flags) {
 908                         dput (dentry);
 909                         err = -EBUSY;
 910                         goto out_err;
 911                 }
 912                 rpci->nkern_readwriters++;
 913                 goto out;
 914         }
 915
 916         err = __rpc_mkpipe(dir, dentry, umode, &rpc_pipe_fops,
 917                            private, ops, flags);
 918         if (err)
 919                 goto out_err;
 920 out:
 921         mutex_unlock(&dir->i_mutex);
 922         return dentry;
 923 out_err:
 924         dentry = ERR_PTR(err);
 925         printk(KERN_WARNING "%s: %s() failed to create pipe %s/%s (errno = %d)\n",
 926                         __FILE__, __func__, parent->d_name.name, name,
 927                         err);
 928         goto out;
 929 }
 930 EXPORT_SYMBOL_GPL(rpc_mkpipe);
 931
 932 /**
 933  * rpc_unlink - remove a pipe
 934  * @dentry: dentry for the pipe, as returned from rpc_mkpipe
 935  *
 936  * After this call, lookups will no longer find the pipe, and any
 937  * attempts to read or write using preexisting opens of the pipe will
 938  * return -EPIPE.
 939  */
 940 int
 941 rpc_unlink(struct dentry *dentry)
 942 {
 943         struct dentry *parent;
 944         struct inode *dir;
 945         int error = 0;
 946
 947         parent = dget_parent(dentry);
 948         dir = parent->d_inode;
 949         mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
 950         error = __rpc_rmpipe(dir, dentry);
 951         mutex_unlock(&dir->i_mutex);
 952         dput(parent);
 953         return error;
 954 }
 955 EXPORT_SYMBOL_GPL(rpc_unlink);
 956
 957 /*
 958  * populate the filesystem
 959  */
 960 static struct super_operations s_ops = {
 961         .alloc_inode    = rpc_alloc_inode,
 962         .destroy_inode  = rpc_destroy_inode,
 963         .statfs         = simple_statfs,
 964 };
 965
 966 #define RPCAUTH_GSSMAGIC 0x67596969
 967
 968 static int
 969 rpc_fill_super(struct super_block *sb, void *data, int silent)
 970 {
 971         struct inode *inode;
 972         struct dentry *root;
 973
 974         sb->s_blocksize = PAGE_CACHE_SIZE;
 975         sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
 976         sb->s_magic = RPCAUTH_GSSMAGIC;
 977         sb->s_op = &s_ops;
 978         sb->s_time_gran = 1;
 979
 980         inode = rpc_get_inode(sb, S_IFDIR | 0755);
 981         if (!inode)
 982                 return -ENOMEM;
 983         root = d_alloc_root(inode);
 984         if (!root) {
 985                 iput(inode);
 986                 return -ENOMEM;
 987         }
 988         if (rpc_populate(root, files, RPCAUTH_lockd, RPCAUTH_RootEOF, NULL))
 989                 goto out;
 990         sb->s_root = root;
 991         return 0;
 992 out:
 993         d_genocide(root);
 994         dput(root);
 995         return -ENOMEM;
 996 }
 997
 998 static int
 999 rpc_get_sb(struct file_system_type *fs_type,
1000                 int flags, const char *dev_name, void *data, struct vfsmount *mnt)
1001 {
1002         return get_sb_single(fs_type, flags, data, rpc_fill_super, mnt);
1003 }
1004
1005 static struct file_system_type rpc_pipe_fs_type = {
1006         .owner          = THIS_MODULE,
1007         .name           = "rpc_pipefs",
1008         .get_sb         = rpc_get_sb,
1009         .kill_sb        = kill_litter_super,
1010 };
1011
1012 static void
1013 init_once(void *foo)
1014 {
1015         struct rpc_inode *rpci = (struct rpc_inode *) foo;
1016
1017         inode_init_once(&rpci->vfs_inode);
1018         rpci->private = NULL;
1019         rpci->nreaders = 0;
1020         rpci->nwriters = 0;
1021         INIT_LIST_HEAD(&rpci->in_upcall);
1022         INIT_LIST_HEAD(&rpci->in_downcall);
1023         INIT_LIST_HEAD(&rpci->pipe);
1024         rpci->pipelen = 0;
1025         init_waitqueue_head(&rpci->waitq);
1026         INIT_DELAYED_WORK(&rpci->queue_timeout,
1027                             rpc_timeout_upcall_queue);
1028         rpci->ops = NULL;
1029 }
1030
1031 int register_rpc_pipefs(void)
1032 {
1033         int err;
1034
1035         rpc_inode_cachep = kmem_cache_create("rpc_inode_cache",
1036                                 sizeof(struct rpc_inode),
1037                                 0, (SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT|
1038                                                 SLAB_MEM_SPREAD),
1039                                 init_once);
1040         if (!rpc_inode_cachep)
1041                 return -ENOMEM;
1042         err = register_filesystem(&rpc_pipe_fs_type);
1043         if (err) {
1044                 kmem_cache_destroy(rpc_inode_cachep);
1045                 return err;
1046         }
1047
1048         return 0;
1049 }
1050
1051 void unregister_rpc_pipefs(void)
1052 {
1053         kmem_cache_destroy(rpc_inode_cachep);
1054         unregister_filesystem(&rpc_pipe_fs_type);
1055 }