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