net/sunrpc/rpc_pipe.c

   1 /*
   2  * net/sunrpc/rpc_pipe.c
   3  *
   4  * Userland/kernel interface for rpcauth_gss.
   5  * Code shamelessly plagiarized from fs/nfsd/nfsctl.c
   6  * and fs/sysfs/inode.c
   7  *
   8  * Copyright (c) 2002, Trond Myklebust <trond.myklebust@fys.uio.no>
   9  *
  10  */
  11 #include <linux/module.h>
  12 #include <linux/slab.h>
  13 #include <linux/string.h>
  14 #include <linux/pagemap.h>
  15 #include <linux/mount.h>
  16 #include <linux/namei.h>
  17 #include <linux/fsnotify.h>
  18 #include <linux/kernel.h>
  19
  20 #include <asm/ioctls.h>
  21 #include <linux/fs.h>
  22 #include <linux/poll.h>
  23 #include <linux/wait.h>
  24 #include <linux/seq_file.h>
  25
  26 #include <linux/sunrpc/clnt.h>
  27 #include <linux/workqueue.h>
  28 #include <linux/sunrpc/rpc_pipe_fs.h>
  29 #include <linux/sunrpc/cache.h>
  30
  31 static struct vfsmount *rpc_mount __read_mostly;
  32 static int rpc_mount_count;
  33
  34 static struct file_system_type rpc_pipe_fs_type;
  35
  36
  37 static struct kmem_cache *rpc_inode_cachep __read_mostly;
  38
  39 #define RPC_UPCALL_TIMEOUT (30*HZ)
  40
  41 static void rpc_purge_list(struct rpc_inode *rpci, struct list_head *head,
  42                 void (*destroy_msg)(struct rpc_pipe_msg *), int err)
  43 {
  44         struct rpc_pipe_msg *msg;
  45
  46         if (list_empty(head))
  47                 return;
  48         do {
  49                 msg = list_entry(head->next, struct rpc_pipe_msg, list);
  50                 list_del(&msg->list);
  51                 msg->errno = err;
  52                 destroy_msg(msg);
  53         } while (!list_empty(head));
  54         wake_up(&rpci->waitq);
  55 }
  56
  57 static void
  58 rpc_timeout_upcall_queue(struct work_struct *work)
  59 {
  60         LIST_HEAD(free_list);
  61         struct rpc_inode *rpci =
  62                 container_of(work, struct rpc_inode, queue_timeout.work);
  63         struct inode *inode = &rpci->vfs_inode;
  64         void (*destroy_msg)(struct rpc_pipe_msg *);
  65
  66         spin_lock(&inode->i_lock);
  67         if (rpci->ops == NULL) {
  68                 spin_unlock(&inode->i_lock);
  69                 return;
  70         }
  71         destroy_msg = rpci->ops->destroy_msg;
  72         if (rpci->nreaders == 0) {
  73                 list_splice_init(&rpci->pipe, &free_list);
  74                 rpci->pipelen = 0;
  75         }
  76         spin_unlock(&inode->i_lock);
  77         rpc_purge_list(rpci, &free_list, destroy_msg, -ETIMEDOUT);
  78 }
  79
  80 /**
  81  * rpc_queue_upcall
  82  * @inode: inode of upcall pipe on which to queue given message
  83  * @msg: message to queue
  84  *
  85  * Call with an @inode created by rpc_mkpipe() to queue an upcall.
  86  * A userspace process may then later read the upcall by performing a
  87  * read on an open file for this inode.  It is up to the caller to
  88  * initialize the fields of @msg (other than @msg->list) appropriately.
  89  */
  90 int
  91 rpc_queue_upcall(struct inode *inode, struct rpc_pipe_msg *msg)
  92 {
  93         struct rpc_inode *rpci = RPC_I(inode);
  94         int res = -EPIPE;
  95
  96         spin_lock(&inode->i_lock);
  97         if (rpci->ops == NULL)
  98                 goto out;
  99         if (rpci->nreaders) {
 100                 list_add_tail(&msg->list, &rpci->pipe);
 101                 rpci->pipelen += msg->len;
 102                 res = 0;
 103         } else if (rpci->flags & RPC_PIPE_WAIT_FOR_OPEN) {
 104                 if (list_empty(&rpci->pipe))
 105                         queue_delayed_work(rpciod_workqueue,
 106                                         &rpci->queue_timeout,
 107                                         RPC_UPCALL_TIMEOUT);
 108                 list_add_tail(&msg->list, &rpci->pipe);
 109                 rpci->pipelen += msg->len;
 110                 res = 0;
 111         }
 112 out:
 113         spin_unlock(&inode->i_lock);
 114         wake_up(&rpci->waitq);
 115         return res;
 116 }
 117 EXPORT_SYMBOL_GPL(rpc_queue_upcall);
 118
 119 static inline void
 120 rpc_inode_setowner(struct inode *inode, void *private)
 121 {
 122         RPC_I(inode)->private = private;
 123 }
 124
 125 static void
 126 rpc_close_pipes(struct inode *inode)
 127 {
 128         struct rpc_inode *rpci = RPC_I(inode);
 129         const struct rpc_pipe_ops *ops;
 130         int need_release;
 131
 132         mutex_lock(&inode->i_mutex);
 133         ops = rpci->ops;
 134         if (ops != NULL) {
 135                 LIST_HEAD(free_list);
 136                 spin_lock(&inode->i_lock);
 137                 need_release = rpci->nreaders != 0 || rpci->nwriters != 0;
 138                 rpci->nreaders = 0;
 139                 list_splice_init(&rpci->in_upcall, &free_list);
 140                 list_splice_init(&rpci->pipe, &free_list);
 141                 rpci->pipelen = 0;
 142                 rpci->ops = NULL;
 143                 spin_unlock(&inode->i_lock);
 144                 rpc_purge_list(rpci, &free_list, ops->destroy_msg, -EPIPE);
 145                 rpci->nwriters = 0;
 146                 if (need_release && ops->release_pipe)
 147                         ops->release_pipe(inode);
 148                 cancel_delayed_work_sync(&rpci->queue_timeout);
 149         }
 150         rpc_inode_setowner(inode, NULL);
 151         mutex_unlock(&inode->i_mutex);
 152 }
 153
 154 static struct inode *
 155 rpc_alloc_inode(struct super_block *sb)
 156 {
 157         struct rpc_inode *rpci;
 158         rpci = (struct rpc_inode *)kmem_cache_alloc(rpc_inode_cachep, GFP_KERNEL);
 159         if (!rpci)
 160                 return NULL;
 161         return &rpci->vfs_inode;
 162 }
 163
 164 static void
 165 rpc_destroy_inode(struct inode *inode)
 166 {
 167         kmem_cache_free(rpc_inode_cachep, RPC_I(inode));
 168 }
 169
 170 static int
 171 rpc_pipe_open(struct inode *inode, struct file *filp)
 172 {
 173         struct rpc_inode *rpci = RPC_I(inode);
 174         int first_open;
 175         int res = -ENXIO;
 176
 177         mutex_lock(&inode->i_mutex);
 178         if (rpci->ops == NULL)
 179                 goto out;
 180         first_open = rpci->nreaders == 0 && rpci->nwriters == 0;
 181         if (first_open && rpci->ops->open_pipe) {
 182                 res = rpci->ops->open_pipe(inode);
 183                 if (res)
 184                         goto out;
 185         }
 186         if (filp->f_mode & FMODE_READ)
 187                 rpci->nreaders++;
 188         if (filp->f_mode & FMODE_WRITE)
 189                 rpci->nwriters++;
 190         res = 0;
 191 out:
 192         mutex_unlock(&inode->i_mutex);
 193         return res;
 194 }
 195
 196 static int
 197 rpc_pipe_release(struct inode *inode, struct file *filp)
 198 {
 199         struct rpc_inode *rpci = RPC_I(inode);
 200         struct rpc_pipe_msg *msg;
 201         int last_close;
 202
 203         mutex_lock(&inode->i_mutex);
 204         if (rpci->ops == NULL)
 205                 goto out;
 206         msg = (struct rpc_pipe_msg *)filp->private_data;
 207         if (msg != NULL) {
 208                 spin_lock(&inode->i_lock);
 209                 msg->errno = -EAGAIN;
 210                 list_del(&msg->list);
 211                 spin_unlock(&inode->i_lock);
 212                 rpci->ops->destroy_msg(msg);
 213         }
 214         if (filp->f_mode & FMODE_WRITE)
 215                 rpci->nwriters --;
 216         if (filp->f_mode & FMODE_READ) {
 217                 rpci->nreaders --;
 218                 if (rpci->nreaders == 0) {
 219                         LIST_HEAD(free_list);
 220                         spin_lock(&inode->i_lock);
 221                         list_splice_init(&rpci->pipe, &free_list);
 222                         rpci->pipelen = 0;
 223                         spin_unlock(&inode->i_lock);
 224                         rpc_purge_list(rpci, &free_list,
 225                                         rpci->ops->destroy_msg, -EAGAIN);
 226                 }
 227         }
 228         last_close = rpci->nwriters == 0 && rpci->nreaders == 0;
 229         if (last_close && rpci->ops->release_pipe)
 230                 rpci->ops->release_pipe(inode);
 231 out:
 232         mutex_unlock(&inode->i_mutex);
 233         return 0;
 234 }
 235
 236 static ssize_t
 237 rpc_pipe_read(struct file *filp, char __user *buf, size_t len, loff_t *offset)
 238 {
 239         struct inode *inode = filp->f_path.dentry->d_inode;
 240         struct rpc_inode *rpci = RPC_I(inode);
 241         struct rpc_pipe_msg *msg;
 242         int res = 0;
 243
 244         mutex_lock(&inode->i_mutex);
 245         if (rpci->ops == NULL) {
 246                 res = -EPIPE;
 247                 goto out_unlock;
 248         }
 249         msg = filp->private_data;
 250         if (msg == NULL) {
 251                 spin_lock(&inode->i_lock);
 252                 if (!list_empty(&rpci->pipe)) {
 253                         msg = list_entry(rpci->pipe.next,
 254                                         struct rpc_pipe_msg,
 255                                         list);
 256                         list_move(&msg->list, &rpci->in_upcall);
 257                         rpci->pipelen -= msg->len;
 258                         filp->private_data = msg;
 259                         msg->copied = 0;
 260                 }
 261                 spin_unlock(&inode->i_lock);
 262                 if (msg == NULL)
 263                         goto out_unlock;
 264         }
 265         /* NOTE: it is up to the callback to update msg->copied */
 266         res = rpci->ops->upcall(filp, msg, buf, len);
 267         if (res < 0 || msg->len == msg->copied) {
 268                 filp->private_data = NULL;
 269                 spin_lock(&inode->i_lock);
 270                 list_del(&msg->list);
 271                 spin_unlock(&inode->i_lock);
 272                 rpci->ops->destroy_msg(msg);
 273         }
 274 out_unlock:
 275         mutex_unlock(&inode->i_mutex);
 276         return res;
 277 }
 278
 279 static ssize_t
 280 rpc_pipe_write(struct file *filp, const char __user *buf, size_t len, loff_t *offset)
 281 {
 282         struct inode *inode = filp->f_path.dentry->d_inode;
 283         struct rpc_inode *rpci = RPC_I(inode);
 284         int res;
 285
 286         mutex_lock(&inode->i_mutex);
 287         res = -EPIPE;
 288         if (rpci->ops != NULL)
 289                 res = rpci->ops->downcall(filp, buf, len);
 290         mutex_unlock(&inode->i_mutex);
 291         return res;
 292 }
 293
 294 static unsigned int
 295 rpc_pipe_poll(struct file *filp, struct poll_table_struct *wait)
 296 {
 297         struct rpc_inode *rpci;
 298         unsigned int mask = 0;
 299
 300         rpci = RPC_I(filp->f_path.dentry->d_inode);
 301         poll_wait(filp, &rpci->waitq, wait);
 302
 303         mask = POLLOUT | POLLWRNORM;
 304         if (rpci->ops == NULL)
 305                 mask |= POLLERR | POLLHUP;
 306         if (filp->private_data || !list_empty(&rpci->pipe))
 307                 mask |= POLLIN | POLLRDNORM;
 308         return mask;
 309 }
 310
 311 static int
 312 rpc_pipe_ioctl(struct inode *ino, struct file *filp,
 313                 unsigned int cmd, unsigned long arg)
 314 {
 315         struct rpc_inode *rpci = RPC_I(filp->f_path.dentry->d_inode);
 316         int len;
 317
 318         switch (cmd) {
 319         case FIONREAD:
 320                 if (rpci->ops == NULL)
 321                         return -EPIPE;
 322                 len = rpci->pipelen;
 323                 if (filp->private_data) {
 324                         struct rpc_pipe_msg *msg;
 325                         msg = (struct rpc_pipe_msg *)filp->private_data;
 326                         len += msg->len - msg->copied;
 327                 }
 328                 return put_user(len, (int __user *)arg);
 329         default:
 330                 return -EINVAL;
 331         }
 332 }
 333
 334 static const struct file_operations rpc_pipe_fops = {
 335         .owner          = THIS_MODULE,
 336         .llseek         = no_llseek,
 337         .read           = rpc_pipe_read,
 338         .write          = rpc_pipe_write,
 339         .poll           = rpc_pipe_poll,
 340         .ioctl          = rpc_pipe_ioctl,
 341         .open           = rpc_pipe_open,
 342         .release        = rpc_pipe_release,
 343 };
 344
 345 static int
 346 rpc_show_info(struct seq_file *m, void *v)
 347 {
 348         struct rpc_clnt *clnt = m->private;
 349
 350         seq_printf(m, "RPC server: %s\n", clnt->cl_server);
 351         seq_printf(m, "service: %s (%d) version %d\n", clnt->cl_protname,
 352                         clnt->cl_prog, clnt->cl_vers);
 353         seq_printf(m, "address: %s\n", rpc_peeraddr2str(clnt, RPC_DISPLAY_ADDR));
 354         seq_printf(m, "protocol: %s\n", rpc_peeraddr2str(clnt, RPC_DISPLAY_PROTO));
 355         seq_printf(m, "port: %s\n", rpc_peeraddr2str(clnt, RPC_DISPLAY_PORT));
 356         return 0;
 357 }
 358
 359 static int
 360 rpc_info_open(struct inode *inode, struct file *file)
 361 {
 362         struct rpc_clnt *clnt;
 363         int ret = single_open(file, rpc_show_info, NULL);
 364
 365         if (!ret) {
 366                 struct seq_file *m = file->private_data;
 367                 mutex_lock(&inode->i_mutex);
 368                 clnt = RPC_I(inode)->private;
 369                 if (clnt) {
 370                         kref_get(&clnt->cl_kref);
 371                         m->private = clnt;
 372                 } else {
 373                         single_release(inode, file);
 374                         ret = -EINVAL;
 375                 }
 376                 mutex_unlock(&inode->i_mutex);
 377         }
 378         return ret;
 379 }
 380
 381 static int
 382 rpc_info_release(struct inode *inode, struct file *file)
 383 {
 384         struct seq_file *m = file->private_data;
 385         struct rpc_clnt *clnt = (struct rpc_clnt *)m->private;
 386
 387         if (clnt)
 388                 rpc_release_client(clnt);
 389         return single_release(inode, file);
 390 }
 391
 392 static const struct file_operations rpc_info_operations = {
 393         .owner          = THIS_MODULE,
 394         .open           = rpc_info_open,
 395         .read           = seq_read,
 396         .llseek         = seq_lseek,
 397         .release        = rpc_info_release,
 398 };
 399
 400
 401 /*
 402  * Description of fs contents.
 403  */
 404 struct rpc_filelist {
 405         const char *name;
 406         const struct file_operations *i_fop;
 407         umode_t mode;
 408 };
 409
 410 struct vfsmount *rpc_get_mount(void)
 411 {
 412         int err;
 413
 414         err = simple_pin_fs(&rpc_pipe_fs_type, &rpc_mount, &rpc_mount_count);
 415         if (err != 0)
 416                 return ERR_PTR(err);
 417         return rpc_mount;
 418 }
 419
 420 void rpc_put_mount(void)
 421 {
 422         simple_release_fs(&rpc_mount, &rpc_mount_count);
 423 }
 424
 425 static int rpc_delete_dentry(struct dentry *dentry)
 426 {
 427         return 1;
 428 }
 429
 430 static const struct dentry_operations rpc_dentry_operations = {
 431         .d_delete = rpc_delete_dentry,
 432 };
 433
 434 static struct inode *
 435 rpc_get_inode(struct super_block *sb, umode_t mode)
 436 {
 437         struct inode *inode = new_inode(sb);
 438         if (!inode)
 439                 return NULL;
 440         inode->i_mode = mode;
 441         inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
 442         switch(mode & S_IFMT) {
 443                 case S_IFDIR:
 444                         inode->i_fop = &simple_dir_operations;
 445                         inode->i_op = &simple_dir_inode_operations;
 446                         inc_nlink(inode);
 447                 default:
 448                         break;
 449         }
 450         return inode;
 451 }
 452
 453 static int __rpc_create_common(struct inode *dir, struct dentry *dentry,
 454                                umode_t mode,
 455                                const struct file_operations *i_fop,
 456                                void *private)
 457 {
 458         struct inode *inode;
 459
 460         BUG_ON(!d_unhashed(dentry));
 461         inode = rpc_get_inode(dir->i_sb, mode);
 462         if (!inode)
 463                 goto out_err;
 464         inode->i_ino = iunique(dir->i_sb, 100);
 465         if (i_fop)
 466                 inode->i_fop = i_fop;
 467         if (private)
 468                 rpc_inode_setowner(inode, private);
 469         d_add(dentry, inode);
 470         return 0;
 471 out_err:
 472         printk(KERN_WARNING "%s: %s failed to allocate inode for dentry %s\n",
 473                         __FILE__, __func__, dentry->d_name.name);
 474         dput(dentry);
 475         return -ENOMEM;
 476 }
 477
 478 static int __rpc_create(struct inode *dir, struct dentry *dentry,
 479                         umode_t mode,
 480                         const struct file_operations *i_fop,
 481                         void *private)
 482 {
 483         int err;
 484
 485         err = __rpc_create_common(dir, dentry, S_IFREG | mode, i_fop, private);
 486         if (err)
 487                 return err;
 488         fsnotify_create(dir, dentry);
 489         return 0;
 490 }
 491
 492 static int __rpc_mkdir(struct inode *dir, struct dentry *dentry,
 493                        umode_t mode,
 494                        const struct file_operations *i_fop,
 495                        void *private)
 496 {
 497         int err;
 498
 499         err = __rpc_create_common(dir, dentry, S_IFDIR | mode, i_fop, private);
 500         if (err)
 501                 return err;
 502         inc_nlink(dir);
 503         fsnotify_mkdir(dir, dentry);
 504         return 0;
 505 }
 506
 507 static int __rpc_mkpipe(struct inode *dir, struct dentry *dentry,
 508                         umode_t mode,
 509                         const struct file_operations *i_fop,
 510                         void *private,
 511                         const struct rpc_pipe_ops *ops,
 512                         int flags)
 513 {
 514         struct rpc_inode *rpci;
 515         int err;
 516
 517         err = __rpc_create_common(dir, dentry, S_IFIFO | mode, i_fop, private);
 518         if (err)
 519                 return err;
 520         rpci = RPC_I(dentry->d_inode);
 521         rpci->nkern_readwriters = 1;
 522         rpci->private = private;
 523         rpci->flags = flags;
 524         rpci->ops = ops;
 525         fsnotify_create(dir, dentry);
 526         return 0;
 527 }
 528
 529 static int __rpc_rmdir(struct inode *dir, struct dentry *dentry)
 530 {
 531         int ret;
 532
 533         dget(dentry);
 534         ret = simple_rmdir(dir, dentry);
 535         d_delete(dentry);
 536         dput(dentry);
 537         return ret;
 538 }
 539
 540 static int __rpc_unlink(struct inode *dir, struct dentry *dentry)
 541 {
 542         int ret;
 543
 544         dget(dentry);
 545         ret = simple_unlink(dir, dentry);
 546         d_delete(dentry);
 547         dput(dentry);
 548         return ret;
 549 }
 550
 551 static int __rpc_rmpipe(struct inode *dir, struct dentry *dentry)
 552 {
 553         struct inode *inode = dentry->d_inode;
 554         struct rpc_inode *rpci = RPC_I(inode);
 555
 556         rpci->nkern_readwriters--;
 557         if (rpci->nkern_readwriters != 0)
 558                 return 0;
 559         rpc_close_pipes(inode);
 560         return __rpc_unlink(dir, dentry);
 561 }
 562
 563 static struct dentry *__rpc_lookup_create(struct dentry *parent,
 564                                           struct qstr *name)
 565 {
 566         struct dentry *dentry;
 567
 568         dentry = d_lookup(parent, name);
 569         if (!dentry) {
 570                 dentry = d_alloc(parent, name);
 571                 if (!dentry) {
 572                         dentry = ERR_PTR(-ENOMEM);
 573                         goto out_err;
 574                 }
 575         }
 576         if (!dentry->d_inode)
 577                 dentry->d_op = &rpc_dentry_operations;
 578 out_err:
 579         return dentry;
 580 }
 581
 582 static struct dentry *__rpc_lookup_create_exclusive(struct dentry *parent,
 583                                           struct qstr *name)
 584 {
 585         struct dentry *dentry;
 586
 587         dentry = __rpc_lookup_create(parent, name);
 588         if (dentry->d_inode == NULL)
 589                 return dentry;
 590         dput(dentry);
 591         return ERR_PTR(-EEXIST);
 592 }
 593
 594 /*
 595  * FIXME: This probably has races.
 596  */
 597 static void __rpc_depopulate(struct dentry *parent,
 598                              const struct rpc_filelist *files,
 599                              int start, int eof)
 600 {
 601         struct inode *dir = parent->d_inode;
 602         struct dentry *dentry;
 603         struct qstr name;
 604         int i;
 605
 606         for (i = start; i < eof; i++) {
 607                 name.name = files[i].name;
 608                 name.len = strlen(files[i].name);
 609                 name.hash = full_name_hash(name.name, name.len);
 610                 dentry = d_lookup(parent, &name);
 611
 612                 if (dentry == NULL)
 613                         continue;
 614                 if (dentry->d_inode == NULL)
 615                         goto next;
 616                 switch (dentry->d_inode->i_mode & S_IFMT) {
 617                         default:
 618                                 BUG();
 619                         case S_IFREG:
 620                                 __rpc_unlink(dir, dentry);
 621                                 break;
 622                         case S_IFDIR:
 623                                 __rpc_rmdir(dir, dentry);
 624                 }
 625 next:
 626                 dput(dentry);
 627         }
 628 }
 629
 630 static void rpc_depopulate(struct dentry *parent,
 631                            const struct rpc_filelist *files,
 632                            int start, int eof)
 633 {
 634         struct inode *dir = parent->d_inode;
 635
 636         mutex_lock_nested(&dir->i_mutex, I_MUTEX_CHILD);
 637         __rpc_depopulate(parent, files, start, eof);
 638         mutex_unlock(&dir->i_mutex);
 639 }
 640
 641 static int rpc_populate(struct dentry *parent,
 642                         const struct rpc_filelist *files,
 643                         int start, int eof,
 644                         void *private)
 645 {
 646         struct inode *dir = parent->d_inode;
 647         struct dentry *dentry;
 648         int i, err;
 649
 650         mutex_lock(&dir->i_mutex);
 651         for (i = start; i < eof; i++) {
 652                 struct qstr q;
 653
 654                 q.name = files[i].name;
 655                 q.len = strlen(files[i].name);
 656                 q.hash = full_name_hash(q.name, q.len);
 657                 dentry = __rpc_lookup_create_exclusive(parent, &q);
 658                 err = PTR_ERR(dentry);
 659                 if (IS_ERR(dentry))
 660                         goto out_bad;
 661                 switch (files[i].mode & S_IFMT) {
 662                         default:
 663                                 BUG();
 664                         case S_IFREG:
 665                                 err = __rpc_create(dir, dentry,
 666                                                 files[i].mode,
 667                                                 files[i].i_fop,
 668                                                 private);
 669                                 break;
 670                         case S_IFDIR:
 671                                 err = __rpc_mkdir(dir, dentry,
 672                                                 files[i].mode,
 673                                                 NULL,
 674                                                 private);
 675                 }
 676                 if (err != 0)
 677                         goto out_bad;
 678         }
 679         mutex_unlock(&dir->i_mutex);
 680         return 0;
 681 out_bad:
 682         __rpc_depopulate(parent, files, start, eof);
 683         mutex_unlock(&dir->i_mutex);
 684         printk(KERN_WARNING "%s: %s failed to populate directory %s\n",
 685                         __FILE__, __func__, parent->d_name.name);
 686         return err;
 687 }
 688
 689 static struct dentry *rpc_mkdir_populate(struct dentry *parent,
 690                 struct qstr *name, umode_t mode, void *private,
 691                 int (*populate)(struct dentry *, void *), void *args_populate)
 692 {
 693         struct dentry *dentry;
 694         struct inode *dir = parent->d_inode;
 695         int error;
 696
 697         mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
 698         dentry = __rpc_lookup_create_exclusive(parent, name);
 699         if (IS_ERR(dentry))
 700                 goto out;
 701         error = __rpc_mkdir(dir, dentry, mode, NULL, private);
 702         if (error != 0)
 703                 goto out_err;
 704         if (populate != NULL) {
 705                 error = populate(dentry, args_populate);
 706                 if (error)
 707                         goto err_rmdir;
 708         }
 709 out:
 710         mutex_unlock(&dir->i_mutex);
 711         return dentry;
 712 err_rmdir:
 713         __rpc_rmdir(dir, dentry);
 714 out_err:
 715         dentry = ERR_PTR(error);
 716         goto out;
 717 }
 718
 719 static int rpc_rmdir_depopulate(struct dentry *dentry,
 720                 void (*depopulate)(struct dentry *))
 721 {
 722         struct dentry *parent;
 723         struct inode *dir;
 724         int error;
 725
 726         parent = dget_parent(dentry);
 727         dir = parent->d_inode;
 728         mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
 729         if (depopulate != NULL)
 730                 depopulate(dentry);
 731         error = __rpc_rmdir(dir, dentry);
 732         mutex_unlock(&dir->i_mutex);
 733         dput(parent);
 734         return error;
 735 }
 736
 737 /**
 738  * rpc_mkpipe - make an rpc_pipefs file for kernel<->userspace communication
 739  * @parent: dentry of directory to create new "pipe" in
 740  * @name: name of pipe
 741  * @private: private data to associate with the pipe, for the caller's use
 742  * @ops: operations defining the behavior of the pipe: upcall, downcall,
 743  *      release_pipe, open_pipe, and destroy_msg.
 744  * @flags: rpc_inode flags
 745  *
 746  * Data is made available for userspace to read by calls to
 747  * rpc_queue_upcall().  The actual reads will result in calls to
 748  * @ops->upcall, which will be called with the file pointer,
 749  * message, and userspace buffer to copy to.
 750  *
 751  * Writes can come at any time, and do not necessarily have to be
 752  * responses to upcalls.  They will result in calls to @msg->downcall.
 753  *
 754  * The @private argument passed here will be available to all these methods
 755  * from the file pointer, via RPC_I(file->f_dentry->d_inode)->private.
 756  */
 757 struct dentry *rpc_mkpipe(struct dentry *parent, const char *name,
 758                           void *private, const struct rpc_pipe_ops *ops,
 759                           int flags)
 760 {
 761         struct dentry *dentry;
 762         struct inode *dir = parent->d_inode;
 763         umode_t umode = S_IFIFO | S_IRUSR | S_IWUSR;
 764         struct qstr q;
 765         int err;
 766
 767         if (ops->upcall == NULL)
 768                 umode &= ~S_IRUGO;
 769         if (ops->downcall == NULL)
 770                 umode &= ~S_IWUGO;
 771
 772         q.name = name;
 773         q.len = strlen(name);
 774         q.hash = full_name_hash(q.name, q.len),
 775
 776         mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
 777         dentry = __rpc_lookup_create(parent, &q);
 778         if (IS_ERR(dentry))
 779                 goto out;
 780         if (dentry->d_inode) {
 781                 struct rpc_inode *rpci = RPC_I(dentry->d_inode);
 782                 if (rpci->private != private ||
 783                                 rpci->ops != ops ||
 784                                 rpci->flags != flags) {
 785                         dput (dentry);
 786                         err = -EBUSY;
 787                         goto out_err;
 788                 }
 789                 rpci->nkern_readwriters++;
 790                 goto out;
 791         }
 792
 793         err = __rpc_mkpipe(dir, dentry, umode, &rpc_pipe_fops,
 794                            private, ops, flags);
 795         if (err)
 796                 goto out_err;
 797 out:
 798         mutex_unlock(&dir->i_mutex);
 799         return dentry;
 800 out_err:
 801         dentry = ERR_PTR(err);
 802         printk(KERN_WARNING "%s: %s() failed to create pipe %s/%s (errno = %d)\n",
 803                         __FILE__, __func__, parent->d_name.name, name,
 804                         err);
 805         goto out;
 806 }
 807 EXPORT_SYMBOL_GPL(rpc_mkpipe);
 808
 809 /**
 810  * rpc_unlink - remove a pipe
 811  * @dentry: dentry for the pipe, as returned from rpc_mkpipe
 812  *
 813  * After this call, lookups will no longer find the pipe, and any
 814  * attempts to read or write using preexisting opens of the pipe will
 815  * return -EPIPE.
 816  */
 817 int
 818 rpc_unlink(struct dentry *dentry)
 819 {
 820         struct dentry *parent;
 821         struct inode *dir;
 822         int error = 0;
 823
 824         parent = dget_parent(dentry);
 825         dir = parent->d_inode;
 826         mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
 827         error = __rpc_rmpipe(dir, dentry);
 828         mutex_unlock(&dir->i_mutex);
 829         dput(parent);
 830         return error;
 831 }
 832 EXPORT_SYMBOL_GPL(rpc_unlink);
 833
 834 enum {
 835         RPCAUTH_info,
 836         RPCAUTH_EOF
 837 };
 838
 839 static const struct rpc_filelist authfiles[] = {
 840         [RPCAUTH_info] = {
 841                 .name = "info",
 842                 .i_fop = &rpc_info_operations,
 843                 .mode = S_IFREG | S_IRUSR,
 844         },
 845 };
 846
 847 static int rpc_clntdir_populate(struct dentry *dentry, void *private)
 848 {
 849         return rpc_populate(dentry,
 850                             authfiles, RPCAUTH_info, RPCAUTH_EOF,
 851                             private);
 852 }
 853
 854 static void rpc_clntdir_depopulate(struct dentry *dentry)
 855 {
 856         rpc_depopulate(dentry, authfiles, RPCAUTH_info, RPCAUTH_EOF);
 857 }
 858
 859 /**
 860  * rpc_create_client_dir - Create a new rpc_client directory in rpc_pipefs
 861  * @path: path from the rpc_pipefs root to the new directory
 862  * @rpc_client: rpc client to associate with this directory
 863  *
 864  * This creates a directory at the given @path associated with
 865  * @rpc_clnt, which will contain a file named "info" with some basic
 866  * information about the client, together with any "pipes" that may
 867  * later be created using rpc_mkpipe().
 868  */
 869 struct dentry *rpc_create_client_dir(struct dentry *dentry,
 870                                    struct qstr *name,
 871                                    struct rpc_clnt *rpc_client)
 872 {
 873         return rpc_mkdir_populate(dentry, name, S_IRUGO | S_IXUGO, NULL,
 874                         rpc_clntdir_populate, rpc_client);
 875 }
 876
 877 /**
 878  * rpc_remove_client_dir - Remove a directory created with rpc_create_client_dir()
 879  * @dentry: directory to remove
 880  */
 881 int rpc_remove_client_dir(struct dentry *dentry)
 882 {
 883         return rpc_rmdir_depopulate(dentry, rpc_clntdir_depopulate);
 884 }
 885
 886 static const struct rpc_filelist cache_pipefs_files[3] = {
 887         [0] = {
 888                 .name = "channel",
 889                 .i_fop = &cache_file_operations_pipefs,
 890                 .mode = S_IFIFO|S_IRUSR|S_IWUSR,
 891         },
 892         [1] = {
 893                 .name = "content",
 894                 .i_fop = &content_file_operations_pipefs,
 895                 .mode = S_IFREG|S_IRUSR,
 896         },
 897         [2] = {
 898                 .name = "flush",
 899                 .i_fop = &cache_flush_operations_pipefs,
 900                 .mode = S_IFREG|S_IRUSR|S_IWUSR,
 901         },
 902 };
 903
 904 static int rpc_cachedir_populate(struct dentry *dentry, void *private)
 905 {
 906         return rpc_populate(dentry,
 907                             cache_pipefs_files, 0, 3,
 908                             private);
 909 }
 910
 911 static void rpc_cachedir_depopulate(struct dentry *dentry)
 912 {
 913         rpc_depopulate(dentry, cache_pipefs_files, 0, 3);
 914 }
 915
 916 struct dentry *rpc_create_cache_dir(struct dentry *parent, struct qstr *name,
 917                                     mode_t umode, struct cache_detail *cd)
 918 {
 919         return rpc_mkdir_populate(parent, name, umode, NULL,
 920                         rpc_cachedir_populate, cd);
 921 }
 922
 923 void rpc_remove_cache_dir(struct dentry *dentry)
 924 {
 925         rpc_rmdir_depopulate(dentry, rpc_cachedir_depopulate);
 926 }
 927
 928 /*
 929  * populate the filesystem
 930  */
 931 static struct super_operations s_ops = {
 932         .alloc_inode    = rpc_alloc_inode,
 933         .destroy_inode  = rpc_destroy_inode,
 934         .statfs         = simple_statfs,
 935 };
 936
 937 #define RPCAUTH_GSSMAGIC 0x67596969
 938
 939 /*
 940  * We have a single directory with 1 node in it.
 941  */
 942 enum {
 943         RPCAUTH_lockd,
 944         RPCAUTH_mount,
 945         RPCAUTH_nfs,
 946         RPCAUTH_portmap,
 947         RPCAUTH_statd,
 948         RPCAUTH_nfsd4_cb,
 949         RPCAUTH_RootEOF
 950 };
 951
 952 static const struct rpc_filelist files[] = {
 953         [RPCAUTH_lockd] = {
 954                 .name = "lockd",
 955                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
 956         },
 957         [RPCAUTH_mount] = {
 958                 .name = "mount",
 959                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
 960         },
 961         [RPCAUTH_nfs] = {
 962                 .name = "nfs",
 963                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
 964         },
 965         [RPCAUTH_portmap] = {
 966                 .name = "portmap",
 967                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
 968         },
 969         [RPCAUTH_statd] = {
 970                 .name = "statd",
 971                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
 972         },
 973         [RPCAUTH_nfsd4_cb] = {
 974                 .name = "nfsd4_cb",
 975                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
 976         },
 977 };
 978
 979 static int
 980 rpc_fill_super(struct super_block *sb, void *data, int silent)
 981 {
 982         struct inode *inode;
 983         struct dentry *root;
 984
 985         sb->s_blocksize = PAGE_CACHE_SIZE;
 986         sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
 987         sb->s_magic = RPCAUTH_GSSMAGIC;
 988         sb->s_op = &s_ops;
 989         sb->s_time_gran = 1;
 990
 991         inode = rpc_get_inode(sb, S_IFDIR | 0755);
 992         if (!inode)
 993                 return -ENOMEM;
 994         root = d_alloc_root(inode);
 995         if (!root) {
 996                 iput(inode);
 997                 return -ENOMEM;
 998         }
 999         if (rpc_populate(root, files, RPCAUTH_lockd, RPCAUTH_RootEOF, NULL))
1000                 goto out;
1001         sb->s_root = root;
1002         return 0;
1003 out:
1004         d_genocide(root);
1005         dput(root);
1006         return -ENOMEM;
1007 }
1008
1009 static int
1010 rpc_get_sb(struct file_system_type *fs_type,
1011                 int flags, const char *dev_name, void *data, struct vfsmount *mnt)
1012 {
1013         return get_sb_single(fs_type, flags, data, rpc_fill_super, mnt);
1014 }
1015
1016 static struct file_system_type rpc_pipe_fs_type = {
1017         .owner          = THIS_MODULE,
1018         .name           = "rpc_pipefs",
1019         .get_sb         = rpc_get_sb,
1020         .kill_sb        = kill_litter_super,
1021 };
1022
1023 static void
1024 init_once(void *foo)
1025 {
1026         struct rpc_inode *rpci = (struct rpc_inode *) foo;
1027
1028         inode_init_once(&rpci->vfs_inode);
1029         rpci->private = NULL;
1030         rpci->nreaders = 0;
1031         rpci->nwriters = 0;
1032         INIT_LIST_HEAD(&rpci->in_upcall);
1033         INIT_LIST_HEAD(&rpci->in_downcall);
1034         INIT_LIST_HEAD(&rpci->pipe);
1035         rpci->pipelen = 0;
1036         init_waitqueue_head(&rpci->waitq);
1037         INIT_DELAYED_WORK(&rpci->queue_timeout,
1038                             rpc_timeout_upcall_queue);
1039         rpci->ops = NULL;
1040 }
1041
1042 int register_rpc_pipefs(void)
1043 {
1044         int err;
1045
1046         rpc_inode_cachep = kmem_cache_create("rpc_inode_cache",
1047                                 sizeof(struct rpc_inode),
1048                                 0, (SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT|
1049                                                 SLAB_MEM_SPREAD),
1050                                 init_once);
1051         if (!rpc_inode_cachep)
1052                 return -ENOMEM;
1053         err = register_filesystem(&rpc_pipe_fs_type);
1054         if (err) {
1055                 kmem_cache_destroy(rpc_inode_cachep);
1056                 return err;
1057         }
1058
1059         return 0;
1060 }
1061
1062 void unregister_rpc_pipefs(void)
1063 {
1064         kmem_cache_destroy(rpc_inode_cachep);
1065         unregister_filesystem(&rpc_pipe_fs_type);
1066 }