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_mnt __read_mostly;
  32 static int rpc_mount_count;
  33
  34 static struct file_system_type rpc_pipe_fs_type;
  35
  36
  37 static struct kmem_cache *rpc_inode_cachep __read_mostly;
  38
  39 #define RPC_UPCALL_TIMEOUT (30*HZ)
  40
  41 static void rpc_purge_list(struct rpc_inode *rpci, struct list_head *head,
  42                 void (*destroy_msg)(struct rpc_pipe_msg *), int err)
  43 {
  44         struct rpc_pipe_msg *msg;
  45
  46         if (list_empty(head))
  47                 return;
  48         do {
  49                 msg = list_entry(head->next, struct rpc_pipe_msg, list);
  50                 list_del_init(&msg->list);
  51                 msg->errno = err;
  52                 destroy_msg(msg);
  53         } while (!list_empty(head));
  54         wake_up(&rpci->waitq);
  55 }
  56
  57 static void
  58 rpc_timeout_upcall_queue(struct work_struct *work)
  59 {
  60         LIST_HEAD(free_list);
  61         struct rpc_inode *rpci =
  62                 container_of(work, struct rpc_inode, queue_timeout.work);
  63         struct inode *inode = &rpci->vfs_inode;
  64         void (*destroy_msg)(struct rpc_pipe_msg *);
  65
  66         spin_lock(&inode->i_lock);
  67         if (rpci->ops == NULL) {
  68                 spin_unlock(&inode->i_lock);
  69                 return;
  70         }
  71         destroy_msg = rpci->ops->destroy_msg;
  72         if (rpci->nreaders == 0) {
  73                 list_splice_init(&rpci->pipe, &free_list);
  74                 rpci->pipelen = 0;
  75         }
  76         spin_unlock(&inode->i_lock);
  77         rpc_purge_list(rpci, &free_list, destroy_msg, -ETIMEDOUT);
  78 }
  79
  80 ssize_t rpc_pipe_generic_upcall(struct file *filp, struct rpc_pipe_msg *msg,
  81                                 char __user *dst, size_t buflen)
  82 {
  83         char *data = (char *)msg->data + msg->copied;
  84         size_t mlen = min(msg->len - msg->copied, buflen);
  85         unsigned long left;
  86
  87         left = copy_to_user(dst, data, mlen);
  88         if (left == mlen) {
  89                 msg->errno = -EFAULT;
  90                 return -EFAULT;
  91         }
  92
  93         mlen -= left;
  94         msg->copied += mlen;
  95         msg->errno = 0;
  96         return mlen;
  97 }
  98 EXPORT_SYMBOL_GPL(rpc_pipe_generic_upcall);
  99
 100 /**
 101  * rpc_queue_upcall - queue an upcall message to userspace
 102  * @inode: inode of upcall pipe on which to queue given message
 103  * @msg: message to queue
 104  *
 105  * Call with an @inode created by rpc_mkpipe() to queue an upcall.
 106  * A userspace process may then later read the upcall by performing a
 107  * read on an open file for this inode.  It is up to the caller to
 108  * initialize the fields of @msg (other than @msg->list) appropriately.
 109  */
 110 int
 111 rpc_queue_upcall(struct inode *inode, struct rpc_pipe_msg *msg)
 112 {
 113         struct rpc_inode *rpci = RPC_I(inode);
 114         int res = -EPIPE;
 115
 116         spin_lock(&inode->i_lock);
 117         if (rpci->ops == NULL)
 118                 goto out;
 119         if (rpci->nreaders) {
 120                 list_add_tail(&msg->list, &rpci->pipe);
 121                 rpci->pipelen += msg->len;
 122                 res = 0;
 123         } else if (rpci->flags & RPC_PIPE_WAIT_FOR_OPEN) {
 124                 if (list_empty(&rpci->pipe))
 125                         queue_delayed_work(rpciod_workqueue,
 126                                         &rpci->queue_timeout,
 127                                         RPC_UPCALL_TIMEOUT);
 128                 list_add_tail(&msg->list, &rpci->pipe);
 129                 rpci->pipelen += msg->len;
 130                 res = 0;
 131         }
 132 out:
 133         spin_unlock(&inode->i_lock);
 134         wake_up(&rpci->waitq);
 135         return res;
 136 }
 137 EXPORT_SYMBOL_GPL(rpc_queue_upcall);
 138
 139 static inline void
 140 rpc_inode_setowner(struct inode *inode, void *private)
 141 {
 142         RPC_I(inode)->private = private;
 143 }
 144
 145 static void
 146 rpc_close_pipes(struct inode *inode)
 147 {
 148         struct rpc_inode *rpci = RPC_I(inode);
 149         const struct rpc_pipe_ops *ops;
 150         int need_release;
 151
 152         mutex_lock(&inode->i_mutex);
 153         ops = rpci->ops;
 154         if (ops != NULL) {
 155                 LIST_HEAD(free_list);
 156                 spin_lock(&inode->i_lock);
 157                 need_release = rpci->nreaders != 0 || rpci->nwriters != 0;
 158                 rpci->nreaders = 0;
 159                 list_splice_init(&rpci->in_upcall, &free_list);
 160                 list_splice_init(&rpci->pipe, &free_list);
 161                 rpci->pipelen = 0;
 162                 rpci->ops = NULL;
 163                 spin_unlock(&inode->i_lock);
 164                 rpc_purge_list(rpci, &free_list, ops->destroy_msg, -EPIPE);
 165                 rpci->nwriters = 0;
 166                 if (need_release && ops->release_pipe)
 167                         ops->release_pipe(inode);
 168                 cancel_delayed_work_sync(&rpci->queue_timeout);
 169         }
 170         rpc_inode_setowner(inode, NULL);
 171         mutex_unlock(&inode->i_mutex);
 172 }
 173
 174 static struct inode *
 175 rpc_alloc_inode(struct super_block *sb)
 176 {
 177         struct rpc_inode *rpci;
 178         rpci = (struct rpc_inode *)kmem_cache_alloc(rpc_inode_cachep, GFP_KERNEL);
 179         if (!rpci)
 180                 return NULL;
 181         return &rpci->vfs_inode;
 182 }
 183
 184 static void
 185 rpc_i_callback(struct rcu_head *head)
 186 {
 187         struct inode *inode = container_of(head, struct inode, i_rcu);
 188         kmem_cache_free(rpc_inode_cachep, RPC_I(inode));
 189 }
 190
 191 static void
 192 rpc_destroy_inode(struct inode *inode)
 193 {
 194         call_rcu(&inode->i_rcu, rpc_i_callback);
 195 }
 196
 197 static int
 198 rpc_pipe_open(struct inode *inode, struct file *filp)
 199 {
 200         struct rpc_inode *rpci = RPC_I(inode);
 201         int first_open;
 202         int res = -ENXIO;
 203
 204         mutex_lock(&inode->i_mutex);
 205         if (rpci->ops == NULL)
 206                 goto out;
 207         first_open = rpci->nreaders == 0 && rpci->nwriters == 0;
 208         if (first_open && rpci->ops->open_pipe) {
 209                 res = rpci->ops->open_pipe(inode);
 210                 if (res)
 211                         goto out;
 212         }
 213         if (filp->f_mode & FMODE_READ)
 214                 rpci->nreaders++;
 215         if (filp->f_mode & FMODE_WRITE)
 216                 rpci->nwriters++;
 217         res = 0;
 218 out:
 219         mutex_unlock(&inode->i_mutex);
 220         return res;
 221 }
 222
 223 static int
 224 rpc_pipe_release(struct inode *inode, struct file *filp)
 225 {
 226         struct rpc_inode *rpci = RPC_I(inode);
 227         struct rpc_pipe_msg *msg;
 228         int last_close;
 229
 230         mutex_lock(&inode->i_mutex);
 231         if (rpci->ops == NULL)
 232                 goto out;
 233         msg = filp->private_data;
 234         if (msg != NULL) {
 235                 spin_lock(&inode->i_lock);
 236                 msg->errno = -EAGAIN;
 237                 list_del_init(&msg->list);
 238                 spin_unlock(&inode->i_lock);
 239                 rpci->ops->destroy_msg(msg);
 240         }
 241         if (filp->f_mode & FMODE_WRITE)
 242                 rpci->nwriters --;
 243         if (filp->f_mode & FMODE_READ) {
 244                 rpci->nreaders --;
 245                 if (rpci->nreaders == 0) {
 246                         LIST_HEAD(free_list);
 247                         spin_lock(&inode->i_lock);
 248                         list_splice_init(&rpci->pipe, &free_list);
 249                         rpci->pipelen = 0;
 250                         spin_unlock(&inode->i_lock);
 251                         rpc_purge_list(rpci, &free_list,
 252                                         rpci->ops->destroy_msg, -EAGAIN);
 253                 }
 254         }
 255         last_close = rpci->nwriters == 0 && rpci->nreaders == 0;
 256         if (last_close && rpci->ops->release_pipe)
 257                 rpci->ops->release_pipe(inode);
 258 out:
 259         mutex_unlock(&inode->i_mutex);
 260         return 0;
 261 }
 262
 263 static ssize_t
 264 rpc_pipe_read(struct file *filp, char __user *buf, size_t len, loff_t *offset)
 265 {
 266         struct inode *inode = filp->f_path.dentry->d_inode;
 267         struct rpc_inode *rpci = RPC_I(inode);
 268         struct rpc_pipe_msg *msg;
 269         int res = 0;
 270
 271         mutex_lock(&inode->i_mutex);
 272         if (rpci->ops == NULL) {
 273                 res = -EPIPE;
 274                 goto out_unlock;
 275         }
 276         msg = filp->private_data;
 277         if (msg == NULL) {
 278                 spin_lock(&inode->i_lock);
 279                 if (!list_empty(&rpci->pipe)) {
 280                         msg = list_entry(rpci->pipe.next,
 281                                         struct rpc_pipe_msg,
 282                                         list);
 283                         list_move(&msg->list, &rpci->in_upcall);
 284                         rpci->pipelen -= msg->len;
 285                         filp->private_data = msg;
 286                         msg->copied = 0;
 287                 }
 288                 spin_unlock(&inode->i_lock);
 289                 if (msg == NULL)
 290                         goto out_unlock;
 291         }
 292         /* NOTE: it is up to the callback to update msg->copied */
 293         res = rpci->ops->upcall(filp, msg, buf, len);
 294         if (res < 0 || msg->len == msg->copied) {
 295                 filp->private_data = NULL;
 296                 spin_lock(&inode->i_lock);
 297                 list_del_init(&msg->list);
 298                 spin_unlock(&inode->i_lock);
 299                 rpci->ops->destroy_msg(msg);
 300         }
 301 out_unlock:
 302         mutex_unlock(&inode->i_mutex);
 303         return res;
 304 }
 305
 306 static ssize_t
 307 rpc_pipe_write(struct file *filp, const char __user *buf, size_t len, loff_t *offset)
 308 {
 309         struct inode *inode = filp->f_path.dentry->d_inode;
 310         struct rpc_inode *rpci = RPC_I(inode);
 311         int res;
 312
 313         mutex_lock(&inode->i_mutex);
 314         res = -EPIPE;
 315         if (rpci->ops != NULL)
 316                 res = rpci->ops->downcall(filp, buf, len);
 317         mutex_unlock(&inode->i_mutex);
 318         return res;
 319 }
 320
 321 static unsigned int
 322 rpc_pipe_poll(struct file *filp, struct poll_table_struct *wait)
 323 {
 324         struct rpc_inode *rpci;
 325         unsigned int mask = 0;
 326
 327         rpci = RPC_I(filp->f_path.dentry->d_inode);
 328         poll_wait(filp, &rpci->waitq, wait);
 329
 330         mask = POLLOUT | POLLWRNORM;
 331         if (rpci->ops == NULL)
 332                 mask |= POLLERR | POLLHUP;
 333         if (filp->private_data || !list_empty(&rpci->pipe))
 334                 mask |= POLLIN | POLLRDNORM;
 335         return mask;
 336 }
 337
 338 static long
 339 rpc_pipe_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 340 {
 341         struct inode *inode = filp->f_path.dentry->d_inode;
 342         struct rpc_inode *rpci = RPC_I(inode);
 343         int len;
 344
 345         switch (cmd) {
 346         case FIONREAD:
 347                 spin_lock(&inode->i_lock);
 348                 if (rpci->ops == NULL) {
 349                         spin_unlock(&inode->i_lock);
 350                         return -EPIPE;
 351                 }
 352                 len = rpci->pipelen;
 353                 if (filp->private_data) {
 354                         struct rpc_pipe_msg *msg;
 355                         msg = filp->private_data;
 356                         len += msg->len - msg->copied;
 357                 }
 358                 spin_unlock(&inode->i_lock);
 359                 return put_user(len, (int __user *)arg);
 360         default:
 361                 return -EINVAL;
 362         }
 363 }
 364
 365 static const struct file_operations rpc_pipe_fops = {
 366         .owner          = THIS_MODULE,
 367         .llseek         = no_llseek,
 368         .read           = rpc_pipe_read,
 369         .write          = rpc_pipe_write,
 370         .poll           = rpc_pipe_poll,
 371         .unlocked_ioctl = rpc_pipe_ioctl,
 372         .open           = rpc_pipe_open,
 373         .release        = rpc_pipe_release,
 374 };
 375
 376 static int
 377 rpc_show_info(struct seq_file *m, void *v)
 378 {
 379         struct rpc_clnt *clnt = m->private;
 380
 381         seq_printf(m, "RPC server: %s\n", clnt->cl_server);
 382         seq_printf(m, "service: %s (%d) version %d\n", clnt->cl_protname,
 383                         clnt->cl_prog, clnt->cl_vers);
 384         seq_printf(m, "address: %s\n", rpc_peeraddr2str(clnt, RPC_DISPLAY_ADDR));
 385         seq_printf(m, "protocol: %s\n", rpc_peeraddr2str(clnt, RPC_DISPLAY_PROTO));
 386         seq_printf(m, "port: %s\n", rpc_peeraddr2str(clnt, RPC_DISPLAY_PORT));
 387         return 0;
 388 }
 389
 390 static int
 391 rpc_info_open(struct inode *inode, struct file *file)
 392 {
 393         struct rpc_clnt *clnt = NULL;
 394         int ret = single_open(file, rpc_show_info, NULL);
 395
 396         if (!ret) {
 397                 struct seq_file *m = file->private_data;
 398
 399                 spin_lock(&file->f_path.dentry->d_lock);
 400                 if (!d_unhashed(file->f_path.dentry))
 401                         clnt = RPC_I(inode)->private;
 402                 if (clnt != NULL && atomic_inc_not_zero(&clnt->cl_count)) {
 403                         spin_unlock(&file->f_path.dentry->d_lock);
 404                         m->private = clnt;
 405                 } else {
 406                         spin_unlock(&file->f_path.dentry->d_lock);
 407                         single_release(inode, file);
 408                         ret = -EINVAL;
 409                 }
 410         }
 411         return ret;
 412 }
 413
 414 static int
 415 rpc_info_release(struct inode *inode, struct file *file)
 416 {
 417         struct seq_file *m = file->private_data;
 418         struct rpc_clnt *clnt = (struct rpc_clnt *)m->private;
 419
 420         if (clnt)
 421                 rpc_release_client(clnt);
 422         return single_release(inode, file);
 423 }
 424
 425 static const struct file_operations rpc_info_operations = {
 426         .owner          = THIS_MODULE,
 427         .open           = rpc_info_open,
 428         .read           = seq_read,
 429         .llseek         = seq_lseek,
 430         .release        = rpc_info_release,
 431 };
 432
 433
 434 /*
 435  * Description of fs contents.
 436  */
 437 struct rpc_filelist {
 438         const char *name;
 439         const struct file_operations *i_fop;
 440         umode_t mode;
 441 };
 442
 443 struct vfsmount *rpc_get_mount(void)
 444 {
 445         int err;
 446
 447         err = simple_pin_fs(&rpc_pipe_fs_type, &rpc_mnt, &rpc_mount_count);
 448         if (err != 0)
 449                 return ERR_PTR(err);
 450         return rpc_mnt;
 451 }
 452 EXPORT_SYMBOL_GPL(rpc_get_mount);
 453
 454 void rpc_put_mount(void)
 455 {
 456         simple_release_fs(&rpc_mnt, &rpc_mount_count);
 457 }
 458 EXPORT_SYMBOL_GPL(rpc_put_mount);
 459
 460 static int rpc_delete_dentry(const struct dentry *dentry)
 461 {
 462         return 1;
 463 }
 464
 465 static const struct dentry_operations rpc_dentry_operations = {
 466         .d_delete = rpc_delete_dentry,
 467 };
 468
 469 static struct inode *
 470 rpc_get_inode(struct super_block *sb, umode_t mode)
 471 {
 472         struct inode *inode = new_inode(sb);
 473         if (!inode)
 474                 return NULL;
 475         inode->i_ino = get_next_ino();
 476         inode->i_mode = mode;
 477         inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
 478         switch (mode & S_IFMT) {
 479         case S_IFDIR:
 480                 inode->i_fop = &simple_dir_operations;
 481                 inode->i_op = &simple_dir_inode_operations;
 482                 inc_nlink(inode);
 483         default:
 484                 break;
 485         }
 486         return inode;
 487 }
 488
 489 static int __rpc_create_common(struct inode *dir, struct dentry *dentry,
 490                                umode_t mode,
 491                                const struct file_operations *i_fop,
 492                                void *private)
 493 {
 494         struct inode *inode;
 495
 496         d_drop(dentry);
 497         inode = rpc_get_inode(dir->i_sb, mode);
 498         if (!inode)
 499                 goto out_err;
 500         inode->i_ino = iunique(dir->i_sb, 100);
 501         if (i_fop)
 502                 inode->i_fop = i_fop;
 503         if (private)
 504                 rpc_inode_setowner(inode, private);
 505         d_add(dentry, inode);
 506         return 0;
 507 out_err:
 508         printk(KERN_WARNING "%s: %s failed to allocate inode for dentry %s\n",
 509                         __FILE__, __func__, dentry->d_name.name);
 510         dput(dentry);
 511         return -ENOMEM;
 512 }
 513
 514 static int __rpc_create(struct inode *dir, struct dentry *dentry,
 515                         umode_t mode,
 516                         const struct file_operations *i_fop,
 517                         void *private)
 518 {
 519         int err;
 520
 521         err = __rpc_create_common(dir, dentry, S_IFREG | mode, i_fop, private);
 522         if (err)
 523                 return err;
 524         fsnotify_create(dir, dentry);
 525         return 0;
 526 }
 527
 528 static int __rpc_mkdir(struct inode *dir, struct dentry *dentry,
 529                        umode_t mode,
 530                        const struct file_operations *i_fop,
 531                        void *private)
 532 {
 533         int err;
 534
 535         err = __rpc_create_common(dir, dentry, S_IFDIR | mode, i_fop, private);
 536         if (err)
 537                 return err;
 538         inc_nlink(dir);
 539         fsnotify_mkdir(dir, dentry);
 540         return 0;
 541 }
 542
 543 static int __rpc_mkpipe(struct inode *dir, struct dentry *dentry,
 544                         umode_t mode,
 545                         const struct file_operations *i_fop,
 546                         void *private,
 547                         const struct rpc_pipe_ops *ops,
 548                         int flags)
 549 {
 550         struct rpc_inode *rpci;
 551         int err;
 552
 553         err = __rpc_create_common(dir, dentry, S_IFIFO | mode, i_fop, private);
 554         if (err)
 555                 return err;
 556         rpci = RPC_I(dentry->d_inode);
 557         rpci->nkern_readwriters = 1;
 558         rpci->private = private;
 559         rpci->flags = flags;
 560         rpci->ops = ops;
 561         fsnotify_create(dir, dentry);
 562         return 0;
 563 }
 564
 565 static int __rpc_rmdir(struct inode *dir, struct dentry *dentry)
 566 {
 567         int ret;
 568
 569         dget(dentry);
 570         ret = simple_rmdir(dir, dentry);
 571         d_delete(dentry);
 572         dput(dentry);
 573         return ret;
 574 }
 575
 576 static int __rpc_unlink(struct inode *dir, struct dentry *dentry)
 577 {
 578         int ret;
 579
 580         dget(dentry);
 581         ret = simple_unlink(dir, dentry);
 582         d_delete(dentry);
 583         dput(dentry);
 584         return ret;
 585 }
 586
 587 static int __rpc_rmpipe(struct inode *dir, struct dentry *dentry)
 588 {
 589         struct inode *inode = dentry->d_inode;
 590         struct rpc_inode *rpci = RPC_I(inode);
 591
 592         rpci->nkern_readwriters--;
 593         if (rpci->nkern_readwriters != 0)
 594                 return 0;
 595         rpc_close_pipes(inode);
 596         return __rpc_unlink(dir, dentry);
 597 }
 598
 599 static struct dentry *__rpc_lookup_create(struct dentry *parent,
 600                                           struct qstr *name)
 601 {
 602         struct dentry *dentry;
 603
 604         dentry = d_lookup(parent, name);
 605         if (!dentry) {
 606                 dentry = d_alloc(parent, name);
 607                 if (!dentry) {
 608                         dentry = ERR_PTR(-ENOMEM);
 609                         goto out_err;
 610                 }
 611         }
 612         if (!dentry->d_inode)
 613                 d_set_d_op(dentry, &rpc_dentry_operations);
 614 out_err:
 615         return dentry;
 616 }
 617
 618 static struct dentry *__rpc_lookup_create_exclusive(struct dentry *parent,
 619                                           struct qstr *name)
 620 {
 621         struct dentry *dentry;
 622
 623         dentry = __rpc_lookup_create(parent, name);
 624         if (IS_ERR(dentry))
 625                 return dentry;
 626         if (dentry->d_inode == NULL)
 627                 return dentry;
 628         dput(dentry);
 629         return ERR_PTR(-EEXIST);
 630 }
 631
 632 /*
 633  * FIXME: This probably has races.
 634  */
 635 static void __rpc_depopulate(struct dentry *parent,
 636                              const struct rpc_filelist *files,
 637                              int start, int eof)
 638 {
 639         struct inode *dir = parent->d_inode;
 640         struct dentry *dentry;
 641         struct qstr name;
 642         int i;
 643
 644         for (i = start; i < eof; i++) {
 645                 name.name = files[i].name;
 646                 name.len = strlen(files[i].name);
 647                 name.hash = full_name_hash(name.name, name.len);
 648                 dentry = d_lookup(parent, &name);
 649
 650                 if (dentry == NULL)
 651                         continue;
 652                 if (dentry->d_inode == NULL)
 653                         goto next;
 654                 switch (dentry->d_inode->i_mode & S_IFMT) {
 655                         default:
 656                                 BUG();
 657                         case S_IFREG:
 658                                 __rpc_unlink(dir, dentry);
 659                                 break;
 660                         case S_IFDIR:
 661                                 __rpc_rmdir(dir, dentry);
 662                 }
 663 next:
 664                 dput(dentry);
 665         }
 666 }
 667
 668 static void rpc_depopulate(struct dentry *parent,
 669                            const struct rpc_filelist *files,
 670                            int start, int eof)
 671 {
 672         struct inode *dir = parent->d_inode;
 673
 674         mutex_lock_nested(&dir->i_mutex, I_MUTEX_CHILD);
 675         __rpc_depopulate(parent, files, start, eof);
 676         mutex_unlock(&dir->i_mutex);
 677 }
 678
 679 static int rpc_populate(struct dentry *parent,
 680                         const struct rpc_filelist *files,
 681                         int start, int eof,
 682                         void *private)
 683 {
 684         struct inode *dir = parent->d_inode;
 685         struct dentry *dentry;
 686         int i, err;
 687
 688         mutex_lock(&dir->i_mutex);
 689         for (i = start; i < eof; i++) {
 690                 struct qstr q;
 691
 692                 q.name = files[i].name;
 693                 q.len = strlen(files[i].name);
 694                 q.hash = full_name_hash(q.name, q.len);
 695                 dentry = __rpc_lookup_create_exclusive(parent, &q);
 696                 err = PTR_ERR(dentry);
 697                 if (IS_ERR(dentry))
 698                         goto out_bad;
 699                 switch (files[i].mode & S_IFMT) {
 700                         default:
 701                                 BUG();
 702                         case S_IFREG:
 703                                 err = __rpc_create(dir, dentry,
 704                                                 files[i].mode,
 705                                                 files[i].i_fop,
 706                                                 private);
 707                                 break;
 708                         case S_IFDIR:
 709                                 err = __rpc_mkdir(dir, dentry,
 710                                                 files[i].mode,
 711                                                 NULL,
 712                                                 private);
 713                 }
 714                 if (err != 0)
 715                         goto out_bad;
 716         }
 717         mutex_unlock(&dir->i_mutex);
 718         return 0;
 719 out_bad:
 720         __rpc_depopulate(parent, files, start, eof);
 721         mutex_unlock(&dir->i_mutex);
 722         printk(KERN_WARNING "%s: %s failed to populate directory %s\n",
 723                         __FILE__, __func__, parent->d_name.name);
 724         return err;
 725 }
 726
 727 static struct dentry *rpc_mkdir_populate(struct dentry *parent,
 728                 struct qstr *name, umode_t mode, void *private,
 729                 int (*populate)(struct dentry *, void *), void *args_populate)
 730 {
 731         struct dentry *dentry;
 732         struct inode *dir = parent->d_inode;
 733         int error;
 734
 735         mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
 736         dentry = __rpc_lookup_create_exclusive(parent, name);
 737         if (IS_ERR(dentry))
 738                 goto out;
 739         error = __rpc_mkdir(dir, dentry, mode, NULL, private);
 740         if (error != 0)
 741                 goto out_err;
 742         if (populate != NULL) {
 743                 error = populate(dentry, args_populate);
 744                 if (error)
 745                         goto err_rmdir;
 746         }
 747 out:
 748         mutex_unlock(&dir->i_mutex);
 749         return dentry;
 750 err_rmdir:
 751         __rpc_rmdir(dir, dentry);
 752 out_err:
 753         dentry = ERR_PTR(error);
 754         goto out;
 755 }
 756
 757 static int rpc_rmdir_depopulate(struct dentry *dentry,
 758                 void (*depopulate)(struct dentry *))
 759 {
 760         struct dentry *parent;
 761         struct inode *dir;
 762         int error;
 763
 764         parent = dget_parent(dentry);
 765         dir = parent->d_inode;
 766         mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
 767         if (depopulate != NULL)
 768                 depopulate(dentry);
 769         error = __rpc_rmdir(dir, dentry);
 770         mutex_unlock(&dir->i_mutex);
 771         dput(parent);
 772         return error;
 773 }
 774
 775 /**
 776  * rpc_mkpipe - make an rpc_pipefs file for kernel<->userspace communication
 777  * @parent: dentry of directory to create new "pipe" in
 778  * @name: name of pipe
 779  * @private: private data to associate with the pipe, for the caller's use
 780  * @ops: operations defining the behavior of the pipe: upcall, downcall,
 781  *      release_pipe, open_pipe, and destroy_msg.
 782  * @flags: rpc_inode flags
 783  *
 784  * Data is made available for userspace to read by calls to
 785  * rpc_queue_upcall().  The actual reads will result in calls to
 786  * @ops->upcall, which will be called with the file pointer,
 787  * message, and userspace buffer to copy to.
 788  *
 789  * Writes can come at any time, and do not necessarily have to be
 790  * responses to upcalls.  They will result in calls to @msg->downcall.
 791  *
 792  * The @private argument passed here will be available to all these methods
 793  * from the file pointer, via RPC_I(file->f_dentry->d_inode)->private.
 794  */
 795 struct dentry *rpc_mkpipe(struct dentry *parent, const char *name,
 796                           void *private, const struct rpc_pipe_ops *ops,
 797                           int flags)
 798 {
 799         struct dentry *dentry;
 800         struct inode *dir = parent->d_inode;
 801         umode_t umode = S_IFIFO | S_IRUSR | S_IWUSR;
 802         struct qstr q;
 803         int err;
 804
 805         if (ops->upcall == NULL)
 806                 umode &= ~S_IRUGO;
 807         if (ops->downcall == NULL)
 808                 umode &= ~S_IWUGO;
 809
 810         q.name = name;
 811         q.len = strlen(name);
 812         q.hash = full_name_hash(q.name, q.len),
 813
 814         mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
 815         dentry = __rpc_lookup_create(parent, &q);
 816         if (IS_ERR(dentry))
 817                 goto out;
 818         if (dentry->d_inode) {
 819                 struct rpc_inode *rpci = RPC_I(dentry->d_inode);
 820                 if (rpci->private != private ||
 821                                 rpci->ops != ops ||
 822                                 rpci->flags != flags) {
 823                         dput (dentry);
 824                         err = -EBUSY;
 825                         goto out_err;
 826                 }
 827                 rpci->nkern_readwriters++;
 828                 goto out;
 829         }
 830
 831         err = __rpc_mkpipe(dir, dentry, umode, &rpc_pipe_fops,
 832                            private, ops, flags);
 833         if (err)
 834                 goto out_err;
 835 out:
 836         mutex_unlock(&dir->i_mutex);
 837         return dentry;
 838 out_err:
 839         dentry = ERR_PTR(err);
 840         printk(KERN_WARNING "%s: %s() failed to create pipe %s/%s (errno = %d)\n",
 841                         __FILE__, __func__, parent->d_name.name, name,
 842                         err);
 843         goto out;
 844 }
 845 EXPORT_SYMBOL_GPL(rpc_mkpipe);
 846
 847 /**
 848  * rpc_unlink - remove a pipe
 849  * @dentry: dentry for the pipe, as returned from rpc_mkpipe
 850  *
 851  * After this call, lookups will no longer find the pipe, and any
 852  * attempts to read or write using preexisting opens of the pipe will
 853  * return -EPIPE.
 854  */
 855 int
 856 rpc_unlink(struct dentry *dentry)
 857 {
 858         struct dentry *parent;
 859         struct inode *dir;
 860         int error = 0;
 861
 862         parent = dget_parent(dentry);
 863         dir = parent->d_inode;
 864         mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
 865         error = __rpc_rmpipe(dir, dentry);
 866         mutex_unlock(&dir->i_mutex);
 867         dput(parent);
 868         return error;
 869 }
 870 EXPORT_SYMBOL_GPL(rpc_unlink);
 871
 872 enum {
 873         RPCAUTH_info,
 874         RPCAUTH_EOF
 875 };
 876
 877 static const struct rpc_filelist authfiles[] = {
 878         [RPCAUTH_info] = {
 879                 .name = "info",
 880                 .i_fop = &rpc_info_operations,
 881                 .mode = S_IFREG | S_IRUSR,
 882         },
 883 };
 884
 885 static int rpc_clntdir_populate(struct dentry *dentry, void *private)
 886 {
 887         return rpc_populate(dentry,
 888                             authfiles, RPCAUTH_info, RPCAUTH_EOF,
 889                             private);
 890 }
 891
 892 static void rpc_clntdir_depopulate(struct dentry *dentry)
 893 {
 894         rpc_depopulate(dentry, authfiles, RPCAUTH_info, RPCAUTH_EOF);
 895 }
 896
 897 /**
 898  * rpc_create_client_dir - Create a new rpc_client directory in rpc_pipefs
 899  * @dentry: dentry from the rpc_pipefs root to the new directory
 900  * @name: &struct qstr for the name
 901  * @rpc_client: rpc client to associate with this directory
 902  *
 903  * This creates a directory at the given @path associated with
 904  * @rpc_clnt, which will contain a file named "info" with some basic
 905  * information about the client, together with any "pipes" that may
 906  * later be created using rpc_mkpipe().
 907  */
 908 struct dentry *rpc_create_client_dir(struct dentry *dentry,
 909                                    struct qstr *name,
 910                                    struct rpc_clnt *rpc_client)
 911 {
 912         return rpc_mkdir_populate(dentry, name, S_IRUGO | S_IXUGO, NULL,
 913                         rpc_clntdir_populate, rpc_client);
 914 }
 915
 916 /**
 917  * rpc_remove_client_dir - Remove a directory created with rpc_create_client_dir()
 918  * @dentry: directory to remove
 919  */
 920 int rpc_remove_client_dir(struct dentry *dentry)
 921 {
 922         return rpc_rmdir_depopulate(dentry, rpc_clntdir_depopulate);
 923 }
 924
 925 static const struct rpc_filelist cache_pipefs_files[3] = {
 926         [0] = {
 927                 .name = "channel",
 928                 .i_fop = &cache_file_operations_pipefs,
 929                 .mode = S_IFREG|S_IRUSR|S_IWUSR,
 930         },
 931         [1] = {
 932                 .name = "content",
 933                 .i_fop = &content_file_operations_pipefs,
 934                 .mode = S_IFREG|S_IRUSR,
 935         },
 936         [2] = {
 937                 .name = "flush",
 938                 .i_fop = &cache_flush_operations_pipefs,
 939                 .mode = S_IFREG|S_IRUSR|S_IWUSR,
 940         },
 941 };
 942
 943 static int rpc_cachedir_populate(struct dentry *dentry, void *private)
 944 {
 945         return rpc_populate(dentry,
 946                             cache_pipefs_files, 0, 3,
 947                             private);
 948 }
 949
 950 static void rpc_cachedir_depopulate(struct dentry *dentry)
 951 {
 952         rpc_depopulate(dentry, cache_pipefs_files, 0, 3);
 953 }
 954
 955 struct dentry *rpc_create_cache_dir(struct dentry *parent, struct qstr *name,
 956                                     mode_t umode, struct cache_detail *cd)
 957 {
 958         return rpc_mkdir_populate(parent, name, umode, NULL,
 959                         rpc_cachedir_populate, cd);
 960 }
 961
 962 void rpc_remove_cache_dir(struct dentry *dentry)
 963 {
 964         rpc_rmdir_depopulate(dentry, rpc_cachedir_depopulate);
 965 }
 966
 967 /*
 968  * populate the filesystem
 969  */
 970 static const struct super_operations s_ops = {
 971         .alloc_inode    = rpc_alloc_inode,
 972         .destroy_inode  = rpc_destroy_inode,
 973         .statfs         = simple_statfs,
 974 };
 975
 976 #define RPCAUTH_GSSMAGIC 0x67596969
 977
 978 /*
 979  * We have a single directory with 1 node in it.
 980  */
 981 enum {
 982         RPCAUTH_lockd,
 983         RPCAUTH_mount,
 984         RPCAUTH_nfs,
 985         RPCAUTH_portmap,
 986         RPCAUTH_statd,
 987         RPCAUTH_nfsd4_cb,
 988         RPCAUTH_cache,
 989         RPCAUTH_RootEOF
 990 };
 991
 992 static const struct rpc_filelist files[] = {
 993         [RPCAUTH_lockd] = {
 994                 .name = "lockd",
 995                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
 996         },
 997         [RPCAUTH_mount] = {
 998                 .name = "mount",
 999                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
1000         },
1001         [RPCAUTH_nfs] = {
1002                 .name = "nfs",
1003                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
1004         },
1005         [RPCAUTH_portmap] = {
1006                 .name = "portmap",
1007                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
1008         },
1009         [RPCAUTH_statd] = {
1010                 .name = "statd",
1011                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
1012         },
1013         [RPCAUTH_nfsd4_cb] = {
1014                 .name = "nfsd4_cb",
1015                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
1016         },
1017         [RPCAUTH_cache] = {
1018                 .name = "cache",
1019                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
1020         },
1021 };
1022
1023 static int
1024 rpc_fill_super(struct super_block *sb, void *data, int silent)
1025 {
1026         struct inode *inode;
1027         struct dentry *root;
1028
1029         sb->s_blocksize = PAGE_CACHE_SIZE;
1030         sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
1031         sb->s_magic = RPCAUTH_GSSMAGIC;
1032         sb->s_op = &s_ops;
1033         sb->s_time_gran = 1;
1034
1035         inode = rpc_get_inode(sb, S_IFDIR | 0755);
1036         if (!inode)
1037                 return -ENOMEM;
1038         sb->s_root = root = d_alloc_root(inode);
1039         if (!root) {
1040                 iput(inode);
1041                 return -ENOMEM;
1042         }
1043         if (rpc_populate(root, files, RPCAUTH_lockd, RPCAUTH_RootEOF, NULL))
1044                 return -ENOMEM;
1045         return 0;
1046 }
1047
1048 static struct dentry *
1049 rpc_mount(struct file_system_type *fs_type,
1050                 int flags, const char *dev_name, void *data)
1051 {
1052         return mount_single(fs_type, flags, data, rpc_fill_super);
1053 }
1054
1055 static struct file_system_type rpc_pipe_fs_type = {
1056         .owner          = THIS_MODULE,
1057         .name           = "rpc_pipefs",
1058         .mount          = rpc_mount,
1059         .kill_sb        = kill_litter_super,
1060 };
1061
1062 static void
1063 init_once(void *foo)
1064 {
1065         struct rpc_inode *rpci = (struct rpc_inode *) foo;
1066
1067         inode_init_once(&rpci->vfs_inode);
1068         rpci->private = NULL;
1069         rpci->nreaders = 0;
1070         rpci->nwriters = 0;
1071         INIT_LIST_HEAD(&rpci->in_upcall);
1072         INIT_LIST_HEAD(&rpci->in_downcall);
1073         INIT_LIST_HEAD(&rpci->pipe);
1074         rpci->pipelen = 0;
1075         init_waitqueue_head(&rpci->waitq);
1076         INIT_DELAYED_WORK(&rpci->queue_timeout,
1077                             rpc_timeout_upcall_queue);
1078         rpci->ops = NULL;
1079 }
1080
1081 int register_rpc_pipefs(void)
1082 {
1083         int err;
1084
1085         rpc_inode_cachep = kmem_cache_create("rpc_inode_cache",
1086                                 sizeof(struct rpc_inode),
1087                                 0, (SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT|
1088                                                 SLAB_MEM_SPREAD),
1089                                 init_once);
1090         if (!rpc_inode_cachep)
1091                 return -ENOMEM;
1092         err = register_filesystem(&rpc_pipe_fs_type);
1093         if (err) {
1094                 kmem_cache_destroy(rpc_inode_cachep);
1095                 return err;
1096         }
1097
1098         return 0;
1099 }
1100
1101 void unregister_rpc_pipefs(void)
1102 {
1103         kmem_cache_destroy(rpc_inode_cachep);
1104         unregister_filesystem(&rpc_pipe_fs_type);
1105 }
1106
1107 /* Make 'mount -t rpc_pipefs ...' autoload this module. */
1108 MODULE_ALIAS("rpc_pipefs");