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