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         INIT_LIST_HEAD(&inode->i_dentry);
 189         kmem_cache_free(rpc_inode_cachep, RPC_I(inode));
 190 }
 191
 192 static void
 193 rpc_destroy_inode(struct inode *inode)
 194 {
 195         call_rcu(&inode->i_rcu, rpc_i_callback);
 196 }
 197
 198 static int
 199 rpc_pipe_open(struct inode *inode, struct file *filp)
 200 {
 201         struct rpc_inode *rpci = RPC_I(inode);
 202         int first_open;
 203         int res = -ENXIO;
 204
 205         mutex_lock(&inode->i_mutex);
 206         if (rpci->ops == NULL)
 207                 goto out;
 208         first_open = rpci->nreaders == 0 && rpci->nwriters == 0;
 209         if (first_open && rpci->ops->open_pipe) {
 210                 res = rpci->ops->open_pipe(inode);
 211                 if (res)
 212                         goto out;
 213         }
 214         if (filp->f_mode & FMODE_READ)
 215                 rpci->nreaders++;
 216         if (filp->f_mode & FMODE_WRITE)
 217                 rpci->nwriters++;
 218         res = 0;
 219 out:
 220         mutex_unlock(&inode->i_mutex);
 221         return res;
 222 }
 223
 224 static int
 225 rpc_pipe_release(struct inode *inode, struct file *filp)
 226 {
 227         struct rpc_inode *rpci = RPC_I(inode);
 228         struct rpc_pipe_msg *msg;
 229         int last_close;
 230
 231         mutex_lock(&inode->i_mutex);
 232         if (rpci->ops == NULL)
 233                 goto out;
 234         msg = filp->private_data;
 235         if (msg != NULL) {
 236                 spin_lock(&inode->i_lock);
 237                 msg->errno = -EAGAIN;
 238                 list_del_init(&msg->list);
 239                 spin_unlock(&inode->i_lock);
 240                 rpci->ops->destroy_msg(msg);
 241         }
 242         if (filp->f_mode & FMODE_WRITE)
 243                 rpci->nwriters --;
 244         if (filp->f_mode & FMODE_READ) {
 245                 rpci->nreaders --;
 246                 if (rpci->nreaders == 0) {
 247                         LIST_HEAD(free_list);
 248                         spin_lock(&inode->i_lock);
 249                         list_splice_init(&rpci->pipe, &free_list);
 250                         rpci->pipelen = 0;
 251                         spin_unlock(&inode->i_lock);
 252                         rpc_purge_list(rpci, &free_list,
 253                                         rpci->ops->destroy_msg, -EAGAIN);
 254                 }
 255         }
 256         last_close = rpci->nwriters == 0 && rpci->nreaders == 0;
 257         if (last_close && rpci->ops->release_pipe)
 258                 rpci->ops->release_pipe(inode);
 259 out:
 260         mutex_unlock(&inode->i_mutex);
 261         return 0;
 262 }
 263
 264 static ssize_t
 265 rpc_pipe_read(struct file *filp, char __user *buf, size_t len, loff_t *offset)
 266 {
 267         struct inode *inode = filp->f_path.dentry->d_inode;
 268         struct rpc_inode *rpci = RPC_I(inode);
 269         struct rpc_pipe_msg *msg;
 270         int res = 0;
 271
 272         mutex_lock(&inode->i_mutex);
 273         if (rpci->ops == NULL) {
 274                 res = -EPIPE;
 275                 goto out_unlock;
 276         }
 277         msg = filp->private_data;
 278         if (msg == NULL) {
 279                 spin_lock(&inode->i_lock);
 280                 if (!list_empty(&rpci->pipe)) {
 281                         msg = list_entry(rpci->pipe.next,
 282                                         struct rpc_pipe_msg,
 283                                         list);
 284                         list_move(&msg->list, &rpci->in_upcall);
 285                         rpci->pipelen -= msg->len;
 286                         filp->private_data = msg;
 287                         msg->copied = 0;
 288                 }
 289                 spin_unlock(&inode->i_lock);
 290                 if (msg == NULL)
 291                         goto out_unlock;
 292         }
 293         /* NOTE: it is up to the callback to update msg->copied */
 294         res = rpci->ops->upcall(filp, msg, buf, len);
 295         if (res < 0 || msg->len == msg->copied) {
 296                 filp->private_data = NULL;
 297                 spin_lock(&inode->i_lock);
 298                 list_del_init(&msg->list);
 299                 spin_unlock(&inode->i_lock);
 300                 rpci->ops->destroy_msg(msg);
 301         }
 302 out_unlock:
 303         mutex_unlock(&inode->i_mutex);
 304         return res;
 305 }
 306
 307 static ssize_t
 308 rpc_pipe_write(struct file *filp, const char __user *buf, size_t len, loff_t *offset)
 309 {
 310         struct inode *inode = filp->f_path.dentry->d_inode;
 311         struct rpc_inode *rpci = RPC_I(inode);
 312         int res;
 313
 314         mutex_lock(&inode->i_mutex);
 315         res = -EPIPE;
 316         if (rpci->ops != NULL)
 317                 res = rpci->ops->downcall(filp, buf, len);
 318         mutex_unlock(&inode->i_mutex);
 319         return res;
 320 }
 321
 322 static unsigned int
 323 rpc_pipe_poll(struct file *filp, struct poll_table_struct *wait)
 324 {
 325         struct rpc_inode *rpci;
 326         unsigned int mask = 0;
 327
 328         rpci = RPC_I(filp->f_path.dentry->d_inode);
 329         poll_wait(filp, &rpci->waitq, wait);
 330
 331         mask = POLLOUT | POLLWRNORM;
 332         if (rpci->ops == NULL)
 333                 mask |= POLLERR | POLLHUP;
 334         if (filp->private_data || !list_empty(&rpci->pipe))
 335                 mask |= POLLIN | POLLRDNORM;
 336         return mask;
 337 }
 338
 339 static long
 340 rpc_pipe_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 341 {
 342         struct inode *inode = filp->f_path.dentry->d_inode;
 343         struct rpc_inode *rpci = RPC_I(inode);
 344         int len;
 345
 346         switch (cmd) {
 347         case FIONREAD:
 348                 spin_lock(&inode->i_lock);
 349                 if (rpci->ops == NULL) {
 350                         spin_unlock(&inode->i_lock);
 351                         return -EPIPE;
 352                 }
 353                 len = rpci->pipelen;
 354                 if (filp->private_data) {
 355                         struct rpc_pipe_msg *msg;
 356                         msg = filp->private_data;
 357                         len += msg->len - msg->copied;
 358                 }
 359                 spin_unlock(&inode->i_lock);
 360                 return put_user(len, (int __user *)arg);
 361         default:
 362                 return -EINVAL;
 363         }
 364 }
 365
 366 static const struct file_operations rpc_pipe_fops = {
 367         .owner          = THIS_MODULE,
 368         .llseek         = no_llseek,
 369         .read           = rpc_pipe_read,
 370         .write          = rpc_pipe_write,
 371         .poll           = rpc_pipe_poll,
 372         .unlocked_ioctl = rpc_pipe_ioctl,
 373         .open           = rpc_pipe_open,
 374         .release        = rpc_pipe_release,
 375 };
 376
 377 static int
 378 rpc_show_info(struct seq_file *m, void *v)
 379 {
 380         struct rpc_clnt *clnt = m->private;
 381
 382         seq_printf(m, "RPC server: %s\n", clnt->cl_server);
 383         seq_printf(m, "service: %s (%d) version %d\n", clnt->cl_protname,
 384                         clnt->cl_prog, clnt->cl_vers);
 385         seq_printf(m, "address: %s\n", rpc_peeraddr2str(clnt, RPC_DISPLAY_ADDR));
 386         seq_printf(m, "protocol: %s\n", rpc_peeraddr2str(clnt, RPC_DISPLAY_PROTO));
 387         seq_printf(m, "port: %s\n", rpc_peeraddr2str(clnt, RPC_DISPLAY_PORT));
 388         return 0;
 389 }
 390
 391 static int
 392 rpc_info_open(struct inode *inode, struct file *file)
 393 {
 394         struct rpc_clnt *clnt = NULL;
 395         int ret = single_open(file, rpc_show_info, NULL);
 396
 397         if (!ret) {
 398                 struct seq_file *m = file->private_data;
 399
 400                 spin_lock(&file->f_path.dentry->d_lock);
 401                 if (!d_unhashed(file->f_path.dentry))
 402                         clnt = RPC_I(inode)->private;
 403                 if (clnt != NULL && atomic_inc_not_zero(&clnt->cl_count)) {
 404                         spin_unlock(&file->f_path.dentry->d_lock);
 405                         m->private = clnt;
 406                 } else {
 407                         spin_unlock(&file->f_path.dentry->d_lock);
 408                         single_release(inode, file);
 409                         ret = -EINVAL;
 410                 }
 411         }
 412         return ret;
 413 }
 414
 415 static int
 416 rpc_info_release(struct inode *inode, struct file *file)
 417 {
 418         struct seq_file *m = file->private_data;
 419         struct rpc_clnt *clnt = (struct rpc_clnt *)m->private;
 420
 421         if (clnt)
 422                 rpc_release_client(clnt);
 423         return single_release(inode, file);
 424 }
 425
 426 static const struct file_operations rpc_info_operations = {
 427         .owner          = THIS_MODULE,
 428         .open           = rpc_info_open,
 429         .read           = seq_read,
 430         .llseek         = seq_lseek,
 431         .release        = rpc_info_release,
 432 };
 433
 434
 435 /*
 436  * Description of fs contents.
 437  */
 438 struct rpc_filelist {
 439         const char *name;
 440         const struct file_operations *i_fop;
 441         umode_t mode;
 442 };
 443
 444 struct vfsmount *rpc_get_mount(void)
 445 {
 446         int err;
 447
 448         err = simple_pin_fs(&rpc_pipe_fs_type, &rpc_mnt, &rpc_mount_count);
 449         if (err != 0)
 450                 return ERR_PTR(err);
 451         return rpc_mnt;
 452 }
 453 EXPORT_SYMBOL_GPL(rpc_get_mount);
 454
 455 void rpc_put_mount(void)
 456 {
 457         simple_release_fs(&rpc_mnt, &rpc_mount_count);
 458 }
 459 EXPORT_SYMBOL_GPL(rpc_put_mount);
 460
 461 static int rpc_delete_dentry(const struct dentry *dentry)
 462 {
 463         return 1;
 464 }
 465
 466 static const struct dentry_operations rpc_dentry_operations = {
 467         .d_delete = rpc_delete_dentry,
 468 };
 469
 470 static struct inode *
 471 rpc_get_inode(struct super_block *sb, umode_t mode)
 472 {
 473         struct inode *inode = new_inode(sb);
 474         if (!inode)
 475                 return NULL;
 476         inode->i_ino = get_next_ino();
 477         inode->i_mode = mode;
 478         inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
 479         switch (mode & S_IFMT) {
 480         case S_IFDIR:
 481                 inode->i_fop = &simple_dir_operations;
 482                 inode->i_op = &simple_dir_inode_operations;
 483                 inc_nlink(inode);
 484         default:
 485                 break;
 486         }
 487         return inode;
 488 }
 489
 490 static int __rpc_create_common(struct inode *dir, struct dentry *dentry,
 491                                umode_t mode,
 492                                const struct file_operations *i_fop,
 493                                void *private)
 494 {
 495         struct inode *inode;
 496
 497         d_drop(dentry);
 498         inode = rpc_get_inode(dir->i_sb, mode);
 499         if (!inode)
 500                 goto out_err;
 501         inode->i_ino = iunique(dir->i_sb, 100);
 502         if (i_fop)
 503                 inode->i_fop = i_fop;
 504         if (private)
 505                 rpc_inode_setowner(inode, private);
 506         d_add(dentry, inode);
 507         return 0;
 508 out_err:
 509         printk(KERN_WARNING "%s: %s failed to allocate inode for dentry %s\n",
 510                         __FILE__, __func__, dentry->d_name.name);
 511         dput(dentry);
 512         return -ENOMEM;
 513 }
 514
 515 static int __rpc_create(struct inode *dir, struct dentry *dentry,
 516                         umode_t mode,
 517                         const struct file_operations *i_fop,
 518                         void *private)
 519 {
 520         int err;
 521
 522         err = __rpc_create_common(dir, dentry, S_IFREG | mode, i_fop, private);
 523         if (err)
 524                 return err;
 525         fsnotify_create(dir, dentry);
 526         return 0;
 527 }
 528
 529 static int __rpc_mkdir(struct inode *dir, struct dentry *dentry,
 530                        umode_t mode,
 531                        const struct file_operations *i_fop,
 532                        void *private)
 533 {
 534         int err;
 535
 536         err = __rpc_create_common(dir, dentry, S_IFDIR | mode, i_fop, private);
 537         if (err)
 538                 return err;
 539         inc_nlink(dir);
 540         fsnotify_mkdir(dir, dentry);
 541         return 0;
 542 }
 543
 544 static int __rpc_mkpipe(struct inode *dir, struct dentry *dentry,
 545                         umode_t mode,
 546                         const struct file_operations *i_fop,
 547                         void *private,
 548                         const struct rpc_pipe_ops *ops,
 549                         int flags)
 550 {
 551         struct rpc_inode *rpci;
 552         int err;
 553
 554         err = __rpc_create_common(dir, dentry, S_IFIFO | mode, i_fop, private);
 555         if (err)
 556                 return err;
 557         rpci = RPC_I(dentry->d_inode);
 558         rpci->nkern_readwriters = 1;
 559         rpci->private = private;
 560         rpci->flags = flags;
 561         rpci->ops = ops;
 562         fsnotify_create(dir, dentry);
 563         return 0;
 564 }
 565
 566 static int __rpc_rmdir(struct inode *dir, struct dentry *dentry)
 567 {
 568         int ret;
 569
 570         dget(dentry);
 571         ret = simple_rmdir(dir, dentry);
 572         d_delete(dentry);
 573         dput(dentry);
 574         return ret;
 575 }
 576
 577 static int __rpc_unlink(struct inode *dir, struct dentry *dentry)
 578 {
 579         int ret;
 580
 581         dget(dentry);
 582         ret = simple_unlink(dir, dentry);
 583         d_delete(dentry);
 584         dput(dentry);
 585         return ret;
 586 }
 587
 588 static int __rpc_rmpipe(struct inode *dir, struct dentry *dentry)
 589 {
 590         struct inode *inode = dentry->d_inode;
 591         struct rpc_inode *rpci = RPC_I(inode);
 592
 593         rpci->nkern_readwriters--;
 594         if (rpci->nkern_readwriters != 0)
 595                 return 0;
 596         rpc_close_pipes(inode);
 597         return __rpc_unlink(dir, dentry);
 598 }
 599
 600 static struct dentry *__rpc_lookup_create(struct dentry *parent,
 601                                           struct qstr *name)
 602 {
 603         struct dentry *dentry;
 604
 605         dentry = d_lookup(parent, name);
 606         if (!dentry) {
 607                 dentry = d_alloc(parent, name);
 608                 if (!dentry) {
 609                         dentry = ERR_PTR(-ENOMEM);
 610                         goto out_err;
 611                 }
 612         }
 613         if (!dentry->d_inode)
 614                 d_set_d_op(dentry, &rpc_dentry_operations);
 615 out_err:
 616         return dentry;
 617 }
 618
 619 static struct dentry *__rpc_lookup_create_exclusive(struct dentry *parent,
 620                                           struct qstr *name)
 621 {
 622         struct dentry *dentry;
 623
 624         dentry = __rpc_lookup_create(parent, name);
 625         if (IS_ERR(dentry))
 626                 return dentry;
 627         if (dentry->d_inode == NULL)
 628                 return dentry;
 629         dput(dentry);
 630         return ERR_PTR(-EEXIST);
 631 }
 632
 633 /*
 634  * FIXME: This probably has races.
 635  */
 636 static void __rpc_depopulate(struct dentry *parent,
 637                              const struct rpc_filelist *files,
 638                              int start, int eof)
 639 {
 640         struct inode *dir = parent->d_inode;
 641         struct dentry *dentry;
 642         struct qstr name;
 643         int i;
 644
 645         for (i = start; i < eof; i++) {
 646                 name.name = files[i].name;
 647                 name.len = strlen(files[i].name);
 648                 name.hash = full_name_hash(name.name, name.len);
 649                 dentry = d_lookup(parent, &name);
 650
 651                 if (dentry == NULL)
 652                         continue;
 653                 if (dentry->d_inode == NULL)
 654                         goto next;
 655                 switch (dentry->d_inode->i_mode & S_IFMT) {
 656                         default:
 657                                 BUG();
 658                         case S_IFREG:
 659                                 __rpc_unlink(dir, dentry);
 660                                 break;
 661                         case S_IFDIR:
 662                                 __rpc_rmdir(dir, dentry);
 663                 }
 664 next:
 665                 dput(dentry);
 666         }
 667 }
 668
 669 static void rpc_depopulate(struct dentry *parent,
 670                            const struct rpc_filelist *files,
 671                            int start, int eof)
 672 {
 673         struct inode *dir = parent->d_inode;
 674
 675         mutex_lock_nested(&dir->i_mutex, I_MUTEX_CHILD);
 676         __rpc_depopulate(parent, files, start, eof);
 677         mutex_unlock(&dir->i_mutex);
 678 }
 679
 680 static int rpc_populate(struct dentry *parent,
 681                         const struct rpc_filelist *files,
 682                         int start, int eof,
 683                         void *private)
 684 {
 685         struct inode *dir = parent->d_inode;
 686         struct dentry *dentry;
 687         int i, err;
 688
 689         mutex_lock(&dir->i_mutex);
 690         for (i = start; i < eof; i++) {
 691                 struct qstr q;
 692
 693                 q.name = files[i].name;
 694                 q.len = strlen(files[i].name);
 695                 q.hash = full_name_hash(q.name, q.len);
 696                 dentry = __rpc_lookup_create_exclusive(parent, &q);
 697                 err = PTR_ERR(dentry);
 698                 if (IS_ERR(dentry))
 699                         goto out_bad;
 700                 switch (files[i].mode & S_IFMT) {
 701                         default:
 702                                 BUG();
 703                         case S_IFREG:
 704                                 err = __rpc_create(dir, dentry,
 705                                                 files[i].mode,
 706                                                 files[i].i_fop,
 707                                                 private);
 708                                 break;
 709                         case S_IFDIR:
 710                                 err = __rpc_mkdir(dir, dentry,
 711                                                 files[i].mode,
 712                                                 NULL,
 713                                                 private);
 714                 }
 715                 if (err != 0)
 716                         goto out_bad;
 717         }
 718         mutex_unlock(&dir->i_mutex);
 719         return 0;
 720 out_bad:
 721         __rpc_depopulate(parent, files, start, eof);
 722         mutex_unlock(&dir->i_mutex);
 723         printk(KERN_WARNING "%s: %s failed to populate directory %s\n",
 724                         __FILE__, __func__, parent->d_name.name);
 725         return err;
 726 }
 727
 728 static struct dentry *rpc_mkdir_populate(struct dentry *parent,
 729                 struct qstr *name, umode_t mode, void *private,
 730                 int (*populate)(struct dentry *, void *), void *args_populate)
 731 {
 732         struct dentry *dentry;
 733         struct inode *dir = parent->d_inode;
 734         int error;
 735
 736         mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
 737         dentry = __rpc_lookup_create_exclusive(parent, name);
 738         if (IS_ERR(dentry))
 739                 goto out;
 740         error = __rpc_mkdir(dir, dentry, mode, NULL, private);
 741         if (error != 0)
 742                 goto out_err;
 743         if (populate != NULL) {
 744                 error = populate(dentry, args_populate);
 745                 if (error)
 746                         goto err_rmdir;
 747         }
 748 out:
 749         mutex_unlock(&dir->i_mutex);
 750         return dentry;
 751 err_rmdir:
 752         __rpc_rmdir(dir, dentry);
 753 out_err:
 754         dentry = ERR_PTR(error);
 755         goto out;
 756 }
 757
 758 static int rpc_rmdir_depopulate(struct dentry *dentry,
 759                 void (*depopulate)(struct dentry *))
 760 {
 761         struct dentry *parent;
 762         struct inode *dir;
 763         int error;
 764
 765         parent = dget_parent(dentry);
 766         dir = parent->d_inode;
 767         mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
 768         if (depopulate != NULL)
 769                 depopulate(dentry);
 770         error = __rpc_rmdir(dir, dentry);
 771         mutex_unlock(&dir->i_mutex);
 772         dput(parent);
 773         return error;
 774 }
 775
 776 /**
 777  * rpc_mkpipe - make an rpc_pipefs file for kernel<->userspace communication
 778  * @parent: dentry of directory to create new "pipe" in
 779  * @name: name of pipe
 780  * @private: private data to associate with the pipe, for the caller's use
 781  * @ops: operations defining the behavior of the pipe: upcall, downcall,
 782  *      release_pipe, open_pipe, and destroy_msg.
 783  * @flags: rpc_inode flags
 784  *
 785  * Data is made available for userspace to read by calls to
 786  * rpc_queue_upcall().  The actual reads will result in calls to
 787  * @ops->upcall, which will be called with the file pointer,
 788  * message, and userspace buffer to copy to.
 789  *
 790  * Writes can come at any time, and do not necessarily have to be
 791  * responses to upcalls.  They will result in calls to @msg->downcall.
 792  *
 793  * The @private argument passed here will be available to all these methods
 794  * from the file pointer, via RPC_I(file->f_dentry->d_inode)->private.
 795  */
 796 struct dentry *rpc_mkpipe(struct dentry *parent, const char *name,
 797                           void *private, const struct rpc_pipe_ops *ops,
 798                           int flags)
 799 {
 800         struct dentry *dentry;
 801         struct inode *dir = parent->d_inode;
 802         umode_t umode = S_IFIFO | S_IRUSR | S_IWUSR;
 803         struct qstr q;
 804         int err;
 805
 806         if (ops->upcall == NULL)
 807                 umode &= ~S_IRUGO;
 808         if (ops->downcall == NULL)
 809                 umode &= ~S_IWUGO;
 810
 811         q.name = name;
 812         q.len = strlen(name);
 813         q.hash = full_name_hash(q.name, q.len),
 814
 815         mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
 816         dentry = __rpc_lookup_create(parent, &q);
 817         if (IS_ERR(dentry))
 818                 goto out;
 819         if (dentry->d_inode) {
 820                 struct rpc_inode *rpci = RPC_I(dentry->d_inode);
 821                 if (rpci->private != private ||
 822                                 rpci->ops != ops ||
 823                                 rpci->flags != flags) {
 824                         dput (dentry);
 825                         err = -EBUSY;
 826                         goto out_err;
 827                 }
 828                 rpci->nkern_readwriters++;
 829                 goto out;
 830         }
 831
 832         err = __rpc_mkpipe(dir, dentry, umode, &rpc_pipe_fops,
 833                            private, ops, flags);
 834         if (err)
 835                 goto out_err;
 836 out:
 837         mutex_unlock(&dir->i_mutex);
 838         return dentry;
 839 out_err:
 840         dentry = ERR_PTR(err);
 841         printk(KERN_WARNING "%s: %s() failed to create pipe %s/%s (errno = %d)\n",
 842                         __FILE__, __func__, parent->d_name.name, name,
 843                         err);
 844         goto out;
 845 }
 846 EXPORT_SYMBOL_GPL(rpc_mkpipe);
 847
 848 /**
 849  * rpc_unlink - remove a pipe
 850  * @dentry: dentry for the pipe, as returned from rpc_mkpipe
 851  *
 852  * After this call, lookups will no longer find the pipe, and any
 853  * attempts to read or write using preexisting opens of the pipe will
 854  * return -EPIPE.
 855  */
 856 int
 857 rpc_unlink(struct dentry *dentry)
 858 {
 859         struct dentry *parent;
 860         struct inode *dir;
 861         int error = 0;
 862
 863         parent = dget_parent(dentry);
 864         dir = parent->d_inode;
 865         mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
 866         error = __rpc_rmpipe(dir, dentry);
 867         mutex_unlock(&dir->i_mutex);
 868         dput(parent);
 869         return error;
 870 }
 871 EXPORT_SYMBOL_GPL(rpc_unlink);
 872
 873 enum {
 874         RPCAUTH_info,
 875         RPCAUTH_EOF
 876 };
 877
 878 static const struct rpc_filelist authfiles[] = {
 879         [RPCAUTH_info] = {
 880                 .name = "info",
 881                 .i_fop = &rpc_info_operations,
 882                 .mode = S_IFREG | S_IRUSR,
 883         },
 884 };
 885
 886 static int rpc_clntdir_populate(struct dentry *dentry, void *private)
 887 {
 888         return rpc_populate(dentry,
 889                             authfiles, RPCAUTH_info, RPCAUTH_EOF,
 890                             private);
 891 }
 892
 893 static void rpc_clntdir_depopulate(struct dentry *dentry)
 894 {
 895         rpc_depopulate(dentry, authfiles, RPCAUTH_info, RPCAUTH_EOF);
 896 }
 897
 898 /**
 899  * rpc_create_client_dir - Create a new rpc_client directory in rpc_pipefs
 900  * @dentry: dentry from the rpc_pipefs root to the new directory
 901  * @name: &struct qstr for the name
 902  * @rpc_client: rpc client to associate with this directory
 903  *
 904  * This creates a directory at the given @path associated with
 905  * @rpc_clnt, which will contain a file named "info" with some basic
 906  * information about the client, together with any "pipes" that may
 907  * later be created using rpc_mkpipe().
 908  */
 909 struct dentry *rpc_create_client_dir(struct dentry *dentry,
 910                                    struct qstr *name,
 911                                    struct rpc_clnt *rpc_client)
 912 {
 913         return rpc_mkdir_populate(dentry, name, S_IRUGO | S_IXUGO, NULL,
 914                         rpc_clntdir_populate, rpc_client);
 915 }
 916
 917 /**
 918  * rpc_remove_client_dir - Remove a directory created with rpc_create_client_dir()
 919  * @dentry: directory to remove
 920  */
 921 int rpc_remove_client_dir(struct dentry *dentry)
 922 {
 923         return rpc_rmdir_depopulate(dentry, rpc_clntdir_depopulate);
 924 }
 925
 926 static const struct rpc_filelist cache_pipefs_files[3] = {
 927         [0] = {
 928                 .name = "channel",
 929                 .i_fop = &cache_file_operations_pipefs,
 930                 .mode = S_IFREG|S_IRUSR|S_IWUSR,
 931         },
 932         [1] = {
 933                 .name = "content",
 934                 .i_fop = &content_file_operations_pipefs,
 935                 .mode = S_IFREG|S_IRUSR,
 936         },
 937         [2] = {
 938                 .name = "flush",
 939                 .i_fop = &cache_flush_operations_pipefs,
 940                 .mode = S_IFREG|S_IRUSR|S_IWUSR,
 941         },
 942 };
 943
 944 static int rpc_cachedir_populate(struct dentry *dentry, void *private)
 945 {
 946         return rpc_populate(dentry,
 947                             cache_pipefs_files, 0, 3,
 948                             private);
 949 }
 950
 951 static void rpc_cachedir_depopulate(struct dentry *dentry)
 952 {
 953         rpc_depopulate(dentry, cache_pipefs_files, 0, 3);
 954 }
 955
 956 struct dentry *rpc_create_cache_dir(struct dentry *parent, struct qstr *name,
 957                                     mode_t umode, struct cache_detail *cd)
 958 {
 959         return rpc_mkdir_populate(parent, name, umode, NULL,
 960                         rpc_cachedir_populate, cd);
 961 }
 962
 963 void rpc_remove_cache_dir(struct dentry *dentry)
 964 {
 965         rpc_rmdir_depopulate(dentry, rpc_cachedir_depopulate);
 966 }
 967
 968 /*
 969  * populate the filesystem
 970  */
 971 static const struct super_operations s_ops = {
 972         .alloc_inode    = rpc_alloc_inode,
 973         .destroy_inode  = rpc_destroy_inode,
 974         .statfs         = simple_statfs,
 975 };
 976
 977 #define RPCAUTH_GSSMAGIC 0x67596969
 978
 979 /*
 980  * We have a single directory with 1 node in it.
 981  */
 982 enum {
 983         RPCAUTH_lockd,
 984         RPCAUTH_mount,
 985         RPCAUTH_nfs,
 986         RPCAUTH_portmap,
 987         RPCAUTH_statd,
 988         RPCAUTH_nfsd4_cb,
 989         RPCAUTH_cache,
 990         RPCAUTH_RootEOF
 991 };
 992
 993 static const struct rpc_filelist files[] = {
 994         [RPCAUTH_lockd] = {
 995                 .name = "lockd",
 996                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
 997         },
 998         [RPCAUTH_mount] = {
 999                 .name = "mount",
1000                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
1001         },
1002         [RPCAUTH_nfs] = {
1003                 .name = "nfs",
1004                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
1005         },
1006         [RPCAUTH_portmap] = {
1007                 .name = "portmap",
1008                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
1009         },
1010         [RPCAUTH_statd] = {
1011                 .name = "statd",
1012                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
1013         },
1014         [RPCAUTH_nfsd4_cb] = {
1015                 .name = "nfsd4_cb",
1016                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
1017         },
1018         [RPCAUTH_cache] = {
1019                 .name = "cache",
1020                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
1021         },
1022 };
1023
1024 static int
1025 rpc_fill_super(struct super_block *sb, void *data, int silent)
1026 {
1027         struct inode *inode;
1028         struct dentry *root;
1029
1030         sb->s_blocksize = PAGE_CACHE_SIZE;
1031         sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
1032         sb->s_magic = RPCAUTH_GSSMAGIC;
1033         sb->s_op = &s_ops;
1034         sb->s_time_gran = 1;
1035
1036         inode = rpc_get_inode(sb, S_IFDIR | 0755);
1037         if (!inode)
1038                 return -ENOMEM;
1039         sb->s_root = root = d_alloc_root(inode);
1040         if (!root) {
1041                 iput(inode);
1042                 return -ENOMEM;
1043         }
1044         if (rpc_populate(root, files, RPCAUTH_lockd, RPCAUTH_RootEOF, NULL))
1045                 return -ENOMEM;
1046         return 0;
1047 }
1048
1049 static struct dentry *
1050 rpc_mount(struct file_system_type *fs_type,
1051                 int flags, const char *dev_name, void *data)
1052 {
1053         return mount_single(fs_type, flags, data, rpc_fill_super);
1054 }
1055
1056 static struct file_system_type rpc_pipe_fs_type = {
1057         .owner          = THIS_MODULE,
1058         .name           = "rpc_pipefs",
1059         .mount          = rpc_mount,
1060         .kill_sb        = kill_litter_super,
1061 };
1062
1063 static void
1064 init_once(void *foo)
1065 {
1066         struct rpc_inode *rpci = (struct rpc_inode *) foo;
1067
1068         inode_init_once(&rpci->vfs_inode);
1069         rpci->private = NULL;
1070         rpci->nreaders = 0;
1071         rpci->nwriters = 0;
1072         INIT_LIST_HEAD(&rpci->in_upcall);
1073         INIT_LIST_HEAD(&rpci->in_downcall);
1074         INIT_LIST_HEAD(&rpci->pipe);
1075         rpci->pipelen = 0;
1076         init_waitqueue_head(&rpci->waitq);
1077         INIT_DELAYED_WORK(&rpci->queue_timeout,
1078                             rpc_timeout_upcall_queue);
1079         rpci->ops = NULL;
1080 }
1081
1082 int register_rpc_pipefs(void)
1083 {
1084         int err;
1085
1086         rpc_inode_cachep = kmem_cache_create("rpc_inode_cache",
1087                                 sizeof(struct rpc_inode),
1088                                 0, (SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT|
1089                                                 SLAB_MEM_SPREAD),
1090                                 init_once);
1091         if (!rpc_inode_cachep)
1092                 return -ENOMEM;
1093         err = register_filesystem(&rpc_pipe_fs_type);
1094         if (err) {
1095                 kmem_cache_destroy(rpc_inode_cachep);
1096                 return err;
1097         }
1098
1099         return 0;
1100 }
1101
1102 void unregister_rpc_pipefs(void)
1103 {
1104         kmem_cache_destroy(rpc_inode_cachep);
1105         unregister_filesystem(&rpc_pipe_fs_type);
1106 }
1107
1108 /* Make 'mount -t rpc_pipefs ...' autoload this module. */
1109 MODULE_ALIAS("rpc_pipefs");