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/poll.h>
  22 #include <linux/wait.h>
  23 #include <linux/seq_file.h>
  24
  25 #include <linux/sunrpc/clnt.h>
  26 #include <linux/workqueue.h>
  27 #include <linux/sunrpc/rpc_pipe_fs.h>
  28 #include <linux/sunrpc/cache.h>
  29 #include <linux/nsproxy.h>
  30 #include <linux/notifier.h>
  31
  32 #include "netns.h"
  33 #include "sunrpc.h"
  34
  35 #define RPCDBG_FACILITY RPCDBG_DEBUG
  36
  37 #define NET_NAME(net)   ((net == &init_net) ? " (init_net)" : "")
  38
  39 static struct file_system_type rpc_pipe_fs_type;
  40
  41
  42 static struct kmem_cache *rpc_inode_cachep __read_mostly;
  43
  44 #define RPC_UPCALL_TIMEOUT (30*HZ)
  45
  46 static BLOCKING_NOTIFIER_HEAD(rpc_pipefs_notifier_list);
  47
  48 int rpc_pipefs_notifier_register(struct notifier_block *nb)
  49 {
  50         return blocking_notifier_chain_cond_register(&rpc_pipefs_notifier_list, nb);
  51 }
  52 EXPORT_SYMBOL_GPL(rpc_pipefs_notifier_register);
  53
  54 void rpc_pipefs_notifier_unregister(struct notifier_block *nb)
  55 {
  56         blocking_notifier_chain_unregister(&rpc_pipefs_notifier_list, nb);
  57 }
  58 EXPORT_SYMBOL_GPL(rpc_pipefs_notifier_unregister);
  59
  60 static void rpc_purge_list(struct rpc_pipe *pipe, struct list_head *head,
  61                 void (*destroy_msg)(struct rpc_pipe_msg *), int err)
  62 {
  63         struct rpc_pipe_msg *msg;
  64
  65         if (list_empty(head))
  66                 return;
  67         do {
  68                 msg = list_entry(head->next, struct rpc_pipe_msg, list);
  69                 list_del_init(&msg->list);
  70                 msg->errno = err;
  71                 destroy_msg(msg);
  72         } while (!list_empty(head));
  73         wake_up(&pipe->waitq);
  74 }
  75
  76 static void
  77 rpc_timeout_upcall_queue(struct work_struct *work)
  78 {
  79         LIST_HEAD(free_list);
  80         struct rpc_pipe *pipe =
  81                 container_of(work, struct rpc_pipe, queue_timeout.work);
  82         void (*destroy_msg)(struct rpc_pipe_msg *);
  83
  84         spin_lock(&pipe->lock);
  85         destroy_msg = pipe->ops->destroy_msg;
  86         if (pipe->nreaders == 0) {
  87                 list_splice_init(&pipe->pipe, &free_list);
  88                 pipe->pipelen = 0;
  89         }
  90         spin_unlock(&pipe->lock);
  91         rpc_purge_list(pipe, &free_list, destroy_msg, -ETIMEDOUT);
  92 }
  93
  94 ssize_t rpc_pipe_generic_upcall(struct file *filp, struct rpc_pipe_msg *msg,
  95                                 char __user *dst, size_t buflen)
  96 {
  97         char *data = (char *)msg->data + msg->copied;
  98         size_t mlen = min(msg->len - msg->copied, buflen);
  99         unsigned long left;
 100
 101         left = copy_to_user(dst, data, mlen);
 102         if (left == mlen) {
 103                 msg->errno = -EFAULT;
 104                 return -EFAULT;
 105         }
 106
 107         mlen -= left;
 108         msg->copied += mlen;
 109         msg->errno = 0;
 110         return mlen;
 111 }
 112 EXPORT_SYMBOL_GPL(rpc_pipe_generic_upcall);
 113
 114 /**
 115  * rpc_queue_upcall - queue an upcall message to userspace
 116  * @inode: inode of upcall pipe on which to queue given message
 117  * @msg: message to queue
 118  *
 119  * Call with an @inode created by rpc_mkpipe() to queue an upcall.
 120  * A userspace process may then later read the upcall by performing a
 121  * read on an open file for this inode.  It is up to the caller to
 122  * initialize the fields of @msg (other than @msg->list) appropriately.
 123  */
 124 int
 125 rpc_queue_upcall(struct rpc_pipe *pipe, struct rpc_pipe_msg *msg)
 126 {
 127         int res = -EPIPE;
 128
 129         spin_lock(&pipe->lock);
 130         if (pipe->nreaders) {
 131                 list_add_tail(&msg->list, &pipe->pipe);
 132                 pipe->pipelen += msg->len;
 133                 res = 0;
 134         } else if (pipe->flags & RPC_PIPE_WAIT_FOR_OPEN) {
 135                 if (list_empty(&pipe->pipe))
 136                         queue_delayed_work(rpciod_workqueue,
 137                                         &pipe->queue_timeout,
 138                                         RPC_UPCALL_TIMEOUT);
 139                 list_add_tail(&msg->list, &pipe->pipe);
 140                 pipe->pipelen += msg->len;
 141                 res = 0;
 142         }
 143         spin_unlock(&pipe->lock);
 144         wake_up(&pipe->waitq);
 145         return res;
 146 }
 147 EXPORT_SYMBOL_GPL(rpc_queue_upcall);
 148
 149 static inline void
 150 rpc_inode_setowner(struct inode *inode, void *private)
 151 {
 152         RPC_I(inode)->private = private;
 153 }
 154
 155 static void
 156 rpc_close_pipes(struct inode *inode)
 157 {
 158         struct rpc_pipe *pipe = RPC_I(inode)->pipe;
 159         int need_release;
 160         LIST_HEAD(free_list);
 161
 162         mutex_lock(&inode->i_mutex);
 163         spin_lock(&pipe->lock);
 164         need_release = pipe->nreaders != 0 || pipe->nwriters != 0;
 165         pipe->nreaders = 0;
 166         list_splice_init(&pipe->in_upcall, &free_list);
 167         list_splice_init(&pipe->pipe, &free_list);
 168         pipe->pipelen = 0;
 169         pipe->dentry = NULL;
 170         spin_unlock(&pipe->lock);
 171         rpc_purge_list(pipe, &free_list, pipe->ops->destroy_msg, -EPIPE);
 172         pipe->nwriters = 0;
 173         if (need_release && pipe->ops->release_pipe)
 174                 pipe->ops->release_pipe(inode);
 175         cancel_delayed_work_sync(&pipe->queue_timeout);
 176         rpc_inode_setowner(inode, NULL);
 177         RPC_I(inode)->pipe = NULL;
 178         mutex_unlock(&inode->i_mutex);
 179 }
 180
 181 static struct inode *
 182 rpc_alloc_inode(struct super_block *sb)
 183 {
 184         struct rpc_inode *rpci;
 185         rpci = (struct rpc_inode *)kmem_cache_alloc(rpc_inode_cachep, GFP_KERNEL);
 186         if (!rpci)
 187                 return NULL;
 188         return &rpci->vfs_inode;
 189 }
 190
 191 static void
 192 rpc_i_callback(struct rcu_head *head)
 193 {
 194         struct inode *inode = container_of(head, struct inode, i_rcu);
 195         kmem_cache_free(rpc_inode_cachep, RPC_I(inode));
 196 }
 197
 198 static void
 199 rpc_destroy_inode(struct inode *inode)
 200 {
 201         call_rcu(&inode->i_rcu, rpc_i_callback);
 202 }
 203
 204 static int
 205 rpc_pipe_open(struct inode *inode, struct file *filp)
 206 {
 207         struct rpc_pipe *pipe;
 208         int first_open;
 209         int res = -ENXIO;
 210
 211         mutex_lock(&inode->i_mutex);
 212         pipe = RPC_I(inode)->pipe;
 213         if (pipe == NULL)
 214                 goto out;
 215         first_open = pipe->nreaders == 0 && pipe->nwriters == 0;
 216         if (first_open && pipe->ops->open_pipe) {
 217                 res = pipe->ops->open_pipe(inode);
 218                 if (res)
 219                         goto out;
 220         }
 221         if (filp->f_mode & FMODE_READ)
 222                 pipe->nreaders++;
 223         if (filp->f_mode & FMODE_WRITE)
 224                 pipe->nwriters++;
 225         res = 0;
 226 out:
 227         mutex_unlock(&inode->i_mutex);
 228         return res;
 229 }
 230
 231 static int
 232 rpc_pipe_release(struct inode *inode, struct file *filp)
 233 {
 234         struct rpc_pipe *pipe;
 235         struct rpc_pipe_msg *msg;
 236         int last_close;
 237
 238         mutex_lock(&inode->i_mutex);
 239         pipe = RPC_I(inode)->pipe;
 240         if (pipe == NULL)
 241                 goto out;
 242         msg = filp->private_data;
 243         if (msg != NULL) {
 244                 spin_lock(&pipe->lock);
 245                 msg->errno = -EAGAIN;
 246                 list_del_init(&msg->list);
 247                 spin_unlock(&pipe->lock);
 248                 pipe->ops->destroy_msg(msg);
 249         }
 250         if (filp->f_mode & FMODE_WRITE)
 251                 pipe->nwriters --;
 252         if (filp->f_mode & FMODE_READ) {
 253                 pipe->nreaders --;
 254                 if (pipe->nreaders == 0) {
 255                         LIST_HEAD(free_list);
 256                         spin_lock(&pipe->lock);
 257                         list_splice_init(&pipe->pipe, &free_list);
 258                         pipe->pipelen = 0;
 259                         spin_unlock(&pipe->lock);
 260                         rpc_purge_list(pipe, &free_list,
 261                                         pipe->ops->destroy_msg, -EAGAIN);
 262                 }
 263         }
 264         last_close = pipe->nwriters == 0 && pipe->nreaders == 0;
 265         if (last_close && pipe->ops->release_pipe)
 266                 pipe->ops->release_pipe(inode);
 267 out:
 268         mutex_unlock(&inode->i_mutex);
 269         return 0;
 270 }
 271
 272 static ssize_t
 273 rpc_pipe_read(struct file *filp, char __user *buf, size_t len, loff_t *offset)
 274 {
 275         struct inode *inode = filp->f_path.dentry->d_inode;
 276         struct rpc_pipe *pipe;
 277         struct rpc_pipe_msg *msg;
 278         int res = 0;
 279
 280         mutex_lock(&inode->i_mutex);
 281         pipe = RPC_I(inode)->pipe;
 282         if (pipe == NULL) {
 283                 res = -EPIPE;
 284                 goto out_unlock;
 285         }
 286         msg = filp->private_data;
 287         if (msg == NULL) {
 288                 spin_lock(&pipe->lock);
 289                 if (!list_empty(&pipe->pipe)) {
 290                         msg = list_entry(pipe->pipe.next,
 291                                         struct rpc_pipe_msg,
 292                                         list);
 293                         list_move(&msg->list, &pipe->in_upcall);
 294                         pipe->pipelen -= msg->len;
 295                         filp->private_data = msg;
 296                         msg->copied = 0;
 297                 }
 298                 spin_unlock(&pipe->lock);
 299                 if (msg == NULL)
 300                         goto out_unlock;
 301         }
 302         /* NOTE: it is up to the callback to update msg->copied */
 303         res = pipe->ops->upcall(filp, msg, buf, len);
 304         if (res < 0 || msg->len == msg->copied) {
 305                 filp->private_data = NULL;
 306                 spin_lock(&pipe->lock);
 307                 list_del_init(&msg->list);
 308                 spin_unlock(&pipe->lock);
 309                 pipe->ops->destroy_msg(msg);
 310         }
 311 out_unlock:
 312         mutex_unlock(&inode->i_mutex);
 313         return res;
 314 }
 315
 316 static ssize_t
 317 rpc_pipe_write(struct file *filp, const char __user *buf, size_t len, loff_t *offset)
 318 {
 319         struct inode *inode = filp->f_path.dentry->d_inode;
 320         int res;
 321
 322         mutex_lock(&inode->i_mutex);
 323         res = -EPIPE;
 324         if (RPC_I(inode)->pipe != NULL)
 325                 res = RPC_I(inode)->pipe->ops->downcall(filp, buf, len);
 326         mutex_unlock(&inode->i_mutex);
 327         return res;
 328 }
 329
 330 static unsigned int
 331 rpc_pipe_poll(struct file *filp, struct poll_table_struct *wait)
 332 {
 333         struct rpc_pipe *pipe = RPC_I(filp->f_path.dentry->d_inode)->pipe;
 334         unsigned int mask = 0;
 335
 336         poll_wait(filp, &pipe->waitq, wait);
 337
 338         mask = POLLOUT | POLLWRNORM;
 339         if (pipe->dentry == NULL)
 340                 mask |= POLLERR | POLLHUP;
 341         if (filp->private_data || !list_empty(&pipe->pipe))
 342                 mask |= POLLIN | POLLRDNORM;
 343         return mask;
 344 }
 345
 346 static long
 347 rpc_pipe_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 348 {
 349         struct inode *inode = filp->f_path.dentry->d_inode;
 350         struct rpc_pipe *pipe;
 351         int len;
 352
 353         switch (cmd) {
 354         case FIONREAD:
 355                 mutex_lock(&inode->i_mutex);
 356                 pipe = RPC_I(inode)->pipe;
 357                 if (pipe == NULL) {
 358                         mutex_unlock(&inode->i_mutex);
 359                         return -EPIPE;
 360                 }
 361                 spin_lock(&pipe->lock);
 362                 len = pipe->pipelen;
 363                 if (filp->private_data) {
 364                         struct rpc_pipe_msg *msg;
 365                         msg = filp->private_data;
 366                         len += msg->len - msg->copied;
 367                 }
 368                 spin_unlock(&pipe->lock);
 369                 mutex_unlock(&inode->i_mutex);
 370                 return put_user(len, (int __user *)arg);
 371         default:
 372                 return -EINVAL;
 373         }
 374 }
 375
 376 static const struct file_operations rpc_pipe_fops = {
 377         .owner          = THIS_MODULE,
 378         .llseek         = no_llseek,
 379         .read           = rpc_pipe_read,
 380         .write          = rpc_pipe_write,
 381         .poll           = rpc_pipe_poll,
 382         .unlocked_ioctl = rpc_pipe_ioctl,
 383         .open           = rpc_pipe_open,
 384         .release        = rpc_pipe_release,
 385 };
 386
 387 static int
 388 rpc_show_info(struct seq_file *m, void *v)
 389 {
 390         struct rpc_clnt *clnt = m->private;
 391
 392         seq_printf(m, "RPC server: %s\n", clnt->cl_server);
 393         seq_printf(m, "service: %s (%d) version %d\n", clnt->cl_protname,
 394                         clnt->cl_prog, clnt->cl_vers);
 395         seq_printf(m, "address: %s\n", rpc_peeraddr2str(clnt, RPC_DISPLAY_ADDR));
 396         seq_printf(m, "protocol: %s\n", rpc_peeraddr2str(clnt, RPC_DISPLAY_PROTO));
 397         seq_printf(m, "port: %s\n", rpc_peeraddr2str(clnt, RPC_DISPLAY_PORT));
 398         return 0;
 399 }
 400
 401 static int
 402 rpc_info_open(struct inode *inode, struct file *file)
 403 {
 404         struct rpc_clnt *clnt = NULL;
 405         int ret = single_open(file, rpc_show_info, NULL);
 406
 407         if (!ret) {
 408                 struct seq_file *m = file->private_data;
 409
 410                 spin_lock(&file->f_path.dentry->d_lock);
 411                 if (!d_unhashed(file->f_path.dentry))
 412                         clnt = RPC_I(inode)->private;
 413                 if (clnt != NULL && atomic_inc_not_zero(&clnt->cl_count)) {
 414                         spin_unlock(&file->f_path.dentry->d_lock);
 415                         m->private = clnt;
 416                 } else {
 417                         spin_unlock(&file->f_path.dentry->d_lock);
 418                         single_release(inode, file);
 419                         ret = -EINVAL;
 420                 }
 421         }
 422         return ret;
 423 }
 424
 425 static int
 426 rpc_info_release(struct inode *inode, struct file *file)
 427 {
 428         struct seq_file *m = file->private_data;
 429         struct rpc_clnt *clnt = (struct rpc_clnt *)m->private;
 430
 431         if (clnt)
 432                 rpc_release_client(clnt);
 433         return single_release(inode, file);
 434 }
 435
 436 static const struct file_operations rpc_info_operations = {
 437         .owner          = THIS_MODULE,
 438         .open           = rpc_info_open,
 439         .read           = seq_read,
 440         .llseek         = seq_lseek,
 441         .release        = rpc_info_release,
 442 };
 443
 444
 445 /*
 446  * Description of fs contents.
 447  */
 448 struct rpc_filelist {
 449         const char *name;
 450         const struct file_operations *i_fop;
 451         umode_t mode;
 452 };
 453
 454 static int rpc_delete_dentry(const struct dentry *dentry)
 455 {
 456         return 1;
 457 }
 458
 459 static const struct dentry_operations rpc_dentry_operations = {
 460         .d_delete = rpc_delete_dentry,
 461 };
 462
 463 static struct inode *
 464 rpc_get_inode(struct super_block *sb, umode_t mode)
 465 {
 466         struct inode *inode = new_inode(sb);
 467         if (!inode)
 468                 return NULL;
 469         inode->i_ino = get_next_ino();
 470         inode->i_mode = mode;
 471         inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
 472         switch (mode & S_IFMT) {
 473         case S_IFDIR:
 474                 inode->i_fop = &simple_dir_operations;
 475                 inode->i_op = &simple_dir_inode_operations;
 476                 inc_nlink(inode);
 477         default:
 478                 break;
 479         }
 480         return inode;
 481 }
 482
 483 static int __rpc_create_common(struct inode *dir, struct dentry *dentry,
 484                                umode_t mode,
 485                                const struct file_operations *i_fop,
 486                                void *private)
 487 {
 488         struct inode *inode;
 489
 490         d_drop(dentry);
 491         inode = rpc_get_inode(dir->i_sb, mode);
 492         if (!inode)
 493                 goto out_err;
 494         inode->i_ino = iunique(dir->i_sb, 100);
 495         if (i_fop)
 496                 inode->i_fop = i_fop;
 497         if (private)
 498                 rpc_inode_setowner(inode, private);
 499         d_add(dentry, inode);
 500         return 0;
 501 out_err:
 502         printk(KERN_WARNING "%s: %s failed to allocate inode for dentry %s\n",
 503                         __FILE__, __func__, dentry->d_name.name);
 504         dput(dentry);
 505         return -ENOMEM;
 506 }
 507
 508 static int __rpc_create(struct inode *dir, struct dentry *dentry,
 509                         umode_t mode,
 510                         const struct file_operations *i_fop,
 511                         void *private)
 512 {
 513         int err;
 514
 515         err = __rpc_create_common(dir, dentry, S_IFREG | mode, i_fop, private);
 516         if (err)
 517                 return err;
 518         fsnotify_create(dir, dentry);
 519         return 0;
 520 }
 521
 522 static int __rpc_mkdir(struct inode *dir, struct dentry *dentry,
 523                        umode_t mode,
 524                        const struct file_operations *i_fop,
 525                        void *private)
 526 {
 527         int err;
 528
 529         err = __rpc_create_common(dir, dentry, S_IFDIR | mode, i_fop, private);
 530         if (err)
 531                 return err;
 532         inc_nlink(dir);
 533         fsnotify_mkdir(dir, dentry);
 534         return 0;
 535 }
 536
 537 static void
 538 init_pipe(struct rpc_pipe *pipe)
 539 {
 540         pipe->nreaders = 0;
 541         pipe->nwriters = 0;
 542         INIT_LIST_HEAD(&pipe->in_upcall);
 543         INIT_LIST_HEAD(&pipe->in_downcall);
 544         INIT_LIST_HEAD(&pipe->pipe);
 545         pipe->pipelen = 0;
 546         init_waitqueue_head(&pipe->waitq);
 547         INIT_DELAYED_WORK(&pipe->queue_timeout,
 548                             rpc_timeout_upcall_queue);
 549         pipe->ops = NULL;
 550         spin_lock_init(&pipe->lock);
 551         pipe->dentry = NULL;
 552 }
 553
 554 void rpc_destroy_pipe_data(struct rpc_pipe *pipe)
 555 {
 556         kfree(pipe);
 557 }
 558 EXPORT_SYMBOL_GPL(rpc_destroy_pipe_data);
 559
 560 struct rpc_pipe *rpc_mkpipe_data(const struct rpc_pipe_ops *ops, int flags)
 561 {
 562         struct rpc_pipe *pipe;
 563
 564         pipe = kzalloc(sizeof(struct rpc_pipe), GFP_KERNEL);
 565         if (!pipe)
 566                 return ERR_PTR(-ENOMEM);
 567         init_pipe(pipe);
 568         pipe->ops = ops;
 569         pipe->flags = flags;
 570         return pipe;
 571 }
 572 EXPORT_SYMBOL_GPL(rpc_mkpipe_data);
 573
 574 static int __rpc_mkpipe_dentry(struct inode *dir, struct dentry *dentry,
 575                                umode_t mode,
 576                                const struct file_operations *i_fop,
 577                                void *private,
 578                                struct rpc_pipe *pipe)
 579 {
 580         struct rpc_inode *rpci;
 581         int err;
 582
 583         err = __rpc_create_common(dir, dentry, S_IFIFO | mode, i_fop, private);
 584         if (err)
 585                 return err;
 586         rpci = RPC_I(dentry->d_inode);
 587         rpci->private = private;
 588         rpci->pipe = pipe;
 589         fsnotify_create(dir, dentry);
 590         return 0;
 591 }
 592
 593 static int __rpc_rmdir(struct inode *dir, struct dentry *dentry)
 594 {
 595         int ret;
 596
 597         dget(dentry);
 598         ret = simple_rmdir(dir, dentry);
 599         d_delete(dentry);
 600         dput(dentry);
 601         return ret;
 602 }
 603
 604 int rpc_rmdir(struct dentry *dentry)
 605 {
 606         struct dentry *parent;
 607         struct inode *dir;
 608         int error;
 609
 610         parent = dget_parent(dentry);
 611         dir = parent->d_inode;
 612         mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
 613         error = __rpc_rmdir(dir, dentry);
 614         mutex_unlock(&dir->i_mutex);
 615         dput(parent);
 616         return error;
 617 }
 618 EXPORT_SYMBOL_GPL(rpc_rmdir);
 619
 620 static int __rpc_unlink(struct inode *dir, struct dentry *dentry)
 621 {
 622         int ret;
 623
 624         dget(dentry);
 625         ret = simple_unlink(dir, dentry);
 626         d_delete(dentry);
 627         dput(dentry);
 628         return ret;
 629 }
 630
 631 static int __rpc_rmpipe(struct inode *dir, struct dentry *dentry)
 632 {
 633         struct inode *inode = dentry->d_inode;
 634
 635         rpc_close_pipes(inode);
 636         return __rpc_unlink(dir, dentry);
 637 }
 638
 639 static struct dentry *__rpc_lookup_create_exclusive(struct dentry *parent,
 640                                           struct qstr *name)
 641 {
 642         struct dentry *dentry;
 643
 644         dentry = d_lookup(parent, name);
 645         if (!dentry) {
 646                 dentry = d_alloc(parent, name);
 647                 if (!dentry)
 648                         return ERR_PTR(-ENOMEM);
 649         }
 650         if (dentry->d_inode == NULL) {
 651                 d_set_d_op(dentry, &rpc_dentry_operations);
 652                 return dentry;
 653         }
 654         dput(dentry);
 655         return ERR_PTR(-EEXIST);
 656 }
 657
 658 /*
 659  * FIXME: This probably has races.
 660  */
 661 static void __rpc_depopulate(struct dentry *parent,
 662                              const struct rpc_filelist *files,
 663                              int start, int eof)
 664 {
 665         struct inode *dir = parent->d_inode;
 666         struct dentry *dentry;
 667         struct qstr name;
 668         int i;
 669
 670         for (i = start; i < eof; i++) {
 671                 name.name = files[i].name;
 672                 name.len = strlen(files[i].name);
 673                 name.hash = full_name_hash(name.name, name.len);
 674                 dentry = d_lookup(parent, &name);
 675
 676                 if (dentry == NULL)
 677                         continue;
 678                 if (dentry->d_inode == NULL)
 679                         goto next;
 680                 switch (dentry->d_inode->i_mode & S_IFMT) {
 681                         default:
 682                                 BUG();
 683                         case S_IFREG:
 684                                 __rpc_unlink(dir, dentry);
 685                                 break;
 686                         case S_IFDIR:
 687                                 __rpc_rmdir(dir, dentry);
 688                 }
 689 next:
 690                 dput(dentry);
 691         }
 692 }
 693
 694 static void rpc_depopulate(struct dentry *parent,
 695                            const struct rpc_filelist *files,
 696                            int start, int eof)
 697 {
 698         struct inode *dir = parent->d_inode;
 699
 700         mutex_lock_nested(&dir->i_mutex, I_MUTEX_CHILD);
 701         __rpc_depopulate(parent, files, start, eof);
 702         mutex_unlock(&dir->i_mutex);
 703 }
 704
 705 static int rpc_populate(struct dentry *parent,
 706                         const struct rpc_filelist *files,
 707                         int start, int eof,
 708                         void *private)
 709 {
 710         struct inode *dir = parent->d_inode;
 711         struct dentry *dentry;
 712         int i, err;
 713
 714         mutex_lock(&dir->i_mutex);
 715         for (i = start; i < eof; i++) {
 716                 struct qstr q;
 717
 718                 q.name = files[i].name;
 719                 q.len = strlen(files[i].name);
 720                 q.hash = full_name_hash(q.name, q.len);
 721                 dentry = __rpc_lookup_create_exclusive(parent, &q);
 722                 err = PTR_ERR(dentry);
 723                 if (IS_ERR(dentry))
 724                         goto out_bad;
 725                 switch (files[i].mode & S_IFMT) {
 726                         default:
 727                                 BUG();
 728                         case S_IFREG:
 729                                 err = __rpc_create(dir, dentry,
 730                                                 files[i].mode,
 731                                                 files[i].i_fop,
 732                                                 private);
 733                                 break;
 734                         case S_IFDIR:
 735                                 err = __rpc_mkdir(dir, dentry,
 736                                                 files[i].mode,
 737                                                 NULL,
 738                                                 private);
 739                 }
 740                 if (err != 0)
 741                         goto out_bad;
 742         }
 743         mutex_unlock(&dir->i_mutex);
 744         return 0;
 745 out_bad:
 746         __rpc_depopulate(parent, files, start, eof);
 747         mutex_unlock(&dir->i_mutex);
 748         printk(KERN_WARNING "%s: %s failed to populate directory %s\n",
 749                         __FILE__, __func__, parent->d_name.name);
 750         return err;
 751 }
 752
 753 static struct dentry *rpc_mkdir_populate(struct dentry *parent,
 754                 struct qstr *name, umode_t mode, void *private,
 755                 int (*populate)(struct dentry *, void *), void *args_populate)
 756 {
 757         struct dentry *dentry;
 758         struct inode *dir = parent->d_inode;
 759         int error;
 760
 761         mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
 762         dentry = __rpc_lookup_create_exclusive(parent, name);
 763         if (IS_ERR(dentry))
 764                 goto out;
 765         error = __rpc_mkdir(dir, dentry, mode, NULL, private);
 766         if (error != 0)
 767                 goto out_err;
 768         if (populate != NULL) {
 769                 error = populate(dentry, args_populate);
 770                 if (error)
 771                         goto err_rmdir;
 772         }
 773 out:
 774         mutex_unlock(&dir->i_mutex);
 775         return dentry;
 776 err_rmdir:
 777         __rpc_rmdir(dir, dentry);
 778 out_err:
 779         dentry = ERR_PTR(error);
 780         goto out;
 781 }
 782
 783 static int rpc_rmdir_depopulate(struct dentry *dentry,
 784                 void (*depopulate)(struct dentry *))
 785 {
 786         struct dentry *parent;
 787         struct inode *dir;
 788         int error;
 789
 790         parent = dget_parent(dentry);
 791         dir = parent->d_inode;
 792         mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
 793         if (depopulate != NULL)
 794                 depopulate(dentry);
 795         error = __rpc_rmdir(dir, dentry);
 796         mutex_unlock(&dir->i_mutex);
 797         dput(parent);
 798         return error;
 799 }
 800
 801 /**
 802  * rpc_mkpipe - make an rpc_pipefs file for kernel<->userspace communication
 803  * @parent: dentry of directory to create new "pipe" in
 804  * @name: name of pipe
 805  * @private: private data to associate with the pipe, for the caller's use
 806  * @ops: operations defining the behavior of the pipe: upcall, downcall,
 807  *      release_pipe, open_pipe, and destroy_msg.
 808  * @flags: rpc_pipe flags
 809  *
 810  * Data is made available for userspace to read by calls to
 811  * rpc_queue_upcall().  The actual reads will result in calls to
 812  * @ops->upcall, which will be called with the file pointer,
 813  * message, and userspace buffer to copy to.
 814  *
 815  * Writes can come at any time, and do not necessarily have to be
 816  * responses to upcalls.  They will result in calls to @msg->downcall.
 817  *
 818  * The @private argument passed here will be available to all these methods
 819  * from the file pointer, via RPC_I(file->f_dentry->d_inode)->private.
 820  */
 821 struct dentry *rpc_mkpipe_dentry(struct dentry *parent, const char *name,
 822                                  void *private, struct rpc_pipe *pipe)
 823 {
 824         struct dentry *dentry;
 825         struct inode *dir = parent->d_inode;
 826         umode_t umode = S_IFIFO | S_IRUSR | S_IWUSR;
 827         struct qstr q;
 828         int err;
 829
 830         if (pipe->ops->upcall == NULL)
 831                 umode &= ~S_IRUGO;
 832         if (pipe->ops->downcall == NULL)
 833                 umode &= ~S_IWUGO;
 834
 835         q.name = name;
 836         q.len = strlen(name);
 837         q.hash = full_name_hash(q.name, q.len),
 838
 839         mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
 840         dentry = __rpc_lookup_create_exclusive(parent, &q);
 841         if (IS_ERR(dentry))
 842                 goto out;
 843         err = __rpc_mkpipe_dentry(dir, dentry, umode, &rpc_pipe_fops,
 844                                   private, pipe);
 845         if (err)
 846                 goto out_err;
 847 out:
 848         mutex_unlock(&dir->i_mutex);
 849         return dentry;
 850 out_err:
 851         dentry = ERR_PTR(err);
 852         printk(KERN_WARNING "%s: %s() failed to create pipe %s/%s (errno = %d)\n",
 853                         __FILE__, __func__, parent->d_name.name, name,
 854                         err);
 855         goto out;
 856 }
 857 EXPORT_SYMBOL_GPL(rpc_mkpipe_dentry);
 858
 859 /**
 860  * rpc_unlink - remove a pipe
 861  * @dentry: dentry for the pipe, as returned from rpc_mkpipe
 862  *
 863  * After this call, lookups will no longer find the pipe, and any
 864  * attempts to read or write using preexisting opens of the pipe will
 865  * return -EPIPE.
 866  */
 867 int
 868 rpc_unlink(struct dentry *dentry)
 869 {
 870         struct dentry *parent;
 871         struct inode *dir;
 872         int error = 0;
 873
 874         parent = dget_parent(dentry);
 875         dir = parent->d_inode;
 876         mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
 877         error = __rpc_rmpipe(dir, dentry);
 878         mutex_unlock(&dir->i_mutex);
 879         dput(parent);
 880         return error;
 881 }
 882 EXPORT_SYMBOL_GPL(rpc_unlink);
 883
 884 enum {
 885         RPCAUTH_info,
 886         RPCAUTH_EOF
 887 };
 888
 889 static const struct rpc_filelist authfiles[] = {
 890         [RPCAUTH_info] = {
 891                 .name = "info",
 892                 .i_fop = &rpc_info_operations,
 893                 .mode = S_IFREG | S_IRUSR,
 894         },
 895 };
 896
 897 static int rpc_clntdir_populate(struct dentry *dentry, void *private)
 898 {
 899         return rpc_populate(dentry,
 900                             authfiles, RPCAUTH_info, RPCAUTH_EOF,
 901                             private);
 902 }
 903
 904 static void rpc_clntdir_depopulate(struct dentry *dentry)
 905 {
 906         rpc_depopulate(dentry, authfiles, RPCAUTH_info, RPCAUTH_EOF);
 907 }
 908
 909 /**
 910  * rpc_create_client_dir - Create a new rpc_client directory in rpc_pipefs
 911  * @dentry: dentry from the rpc_pipefs root to the new directory
 912  * @name: &struct qstr for the name
 913  * @rpc_client: rpc client to associate with this directory
 914  *
 915  * This creates a directory at the given @path associated with
 916  * @rpc_clnt, which will contain a file named "info" with some basic
 917  * information about the client, together with any "pipes" that may
 918  * later be created using rpc_mkpipe().
 919  */
 920 struct dentry *rpc_create_client_dir(struct dentry *dentry,
 921                                    struct qstr *name,
 922                                    struct rpc_clnt *rpc_client)
 923 {
 924         return rpc_mkdir_populate(dentry, name, S_IRUGO | S_IXUGO, NULL,
 925                         rpc_clntdir_populate, rpc_client);
 926 }
 927
 928 /**
 929  * rpc_remove_client_dir - Remove a directory created with rpc_create_client_dir()
 930  * @clnt: rpc client
 931  */
 932 int rpc_remove_client_dir(struct dentry *dentry)
 933 {
 934         return rpc_rmdir_depopulate(dentry, rpc_clntdir_depopulate);
 935 }
 936
 937 static const struct rpc_filelist cache_pipefs_files[3] = {
 938         [0] = {
 939                 .name = "channel",
 940                 .i_fop = &cache_file_operations_pipefs,
 941                 .mode = S_IFREG|S_IRUSR|S_IWUSR,
 942         },
 943         [1] = {
 944                 .name = "content",
 945                 .i_fop = &content_file_operations_pipefs,
 946                 .mode = S_IFREG|S_IRUSR,
 947         },
 948         [2] = {
 949                 .name = "flush",
 950                 .i_fop = &cache_flush_operations_pipefs,
 951                 .mode = S_IFREG|S_IRUSR|S_IWUSR,
 952         },
 953 };
 954
 955 static int rpc_cachedir_populate(struct dentry *dentry, void *private)
 956 {
 957         return rpc_populate(dentry,
 958                             cache_pipefs_files, 0, 3,
 959                             private);
 960 }
 961
 962 static void rpc_cachedir_depopulate(struct dentry *dentry)
 963 {
 964         rpc_depopulate(dentry, cache_pipefs_files, 0, 3);
 965 }
 966
 967 struct dentry *rpc_create_cache_dir(struct dentry *parent, struct qstr *name,
 968                                     umode_t umode, struct cache_detail *cd)
 969 {
 970         return rpc_mkdir_populate(parent, name, umode, NULL,
 971                         rpc_cachedir_populate, cd);
 972 }
 973
 974 void rpc_remove_cache_dir(struct dentry *dentry)
 975 {
 976         rpc_rmdir_depopulate(dentry, rpc_cachedir_depopulate);
 977 }
 978
 979 /*
 980  * populate the filesystem
 981  */
 982 static const struct super_operations s_ops = {
 983         .alloc_inode    = rpc_alloc_inode,
 984         .destroy_inode  = rpc_destroy_inode,
 985         .statfs         = simple_statfs,
 986 };
 987
 988 #define RPCAUTH_GSSMAGIC 0x67596969
 989
 990 /*
 991  * We have a single directory with 1 node in it.
 992  */
 993 enum {
 994         RPCAUTH_lockd,
 995         RPCAUTH_mount,
 996         RPCAUTH_nfs,
 997         RPCAUTH_portmap,
 998         RPCAUTH_statd,
 999         RPCAUTH_nfsd4_cb,
1000         RPCAUTH_cache,
1001         RPCAUTH_RootEOF
1002 };
1003
1004 static const struct rpc_filelist files[] = {
1005         [RPCAUTH_lockd] = {
1006                 .name = "lockd",
1007                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
1008         },
1009         [RPCAUTH_mount] = {
1010                 .name = "mount",
1011                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
1012         },
1013         [RPCAUTH_nfs] = {
1014                 .name = "nfs",
1015                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
1016         },
1017         [RPCAUTH_portmap] = {
1018                 .name = "portmap",
1019                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
1020         },
1021         [RPCAUTH_statd] = {
1022                 .name = "statd",
1023                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
1024         },
1025         [RPCAUTH_nfsd4_cb] = {
1026                 .name = "nfsd4_cb",
1027                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
1028         },
1029         [RPCAUTH_cache] = {
1030                 .name = "cache",
1031                 .mode = S_IFDIR | S_IRUGO | S_IXUGO,
1032         },
1033 };
1034
1035 /*
1036  * This call can be used only in RPC pipefs mount notification hooks.
1037  */
1038 struct dentry *rpc_d_lookup_sb(const struct super_block *sb,
1039                                const unsigned char *dir_name)
1040 {
1041         struct qstr dir = {
1042                 .name = dir_name,
1043                 .len = strlen(dir_name),
1044                 .hash = full_name_hash(dir_name, strlen(dir_name)),
1045         };
1046
1047         return d_lookup(sb->s_root, &dir);
1048 }
1049 EXPORT_SYMBOL_GPL(rpc_d_lookup_sb);
1050
1051 void rpc_pipefs_init_net(struct net *net)
1052 {
1053         struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
1054
1055         mutex_init(&sn->pipefs_sb_lock);
1056 }
1057
1058 /*
1059  * This call will be used for per network namespace operations calls.
1060  * Note: Function will be returned with pipefs_sb_lock taken if superblock was
1061  * found. This lock have to be released by rpc_put_sb_net() when all operations
1062  * will be completed.
1063  */
1064 struct super_block *rpc_get_sb_net(const struct net *net)
1065 {
1066         struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
1067
1068         mutex_lock(&sn->pipefs_sb_lock);
1069         if (sn->pipefs_sb)
1070                 return sn->pipefs_sb;
1071         mutex_unlock(&sn->pipefs_sb_lock);
1072         return NULL;
1073 }
1074 EXPORT_SYMBOL_GPL(rpc_get_sb_net);
1075
1076 void rpc_put_sb_net(const struct net *net)
1077 {
1078         struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
1079
1080         BUG_ON(sn->pipefs_sb == NULL);
1081         mutex_unlock(&sn->pipefs_sb_lock);
1082 }
1083 EXPORT_SYMBOL_GPL(rpc_put_sb_net);
1084
1085 static int
1086 rpc_fill_super(struct super_block *sb, void *data, int silent)
1087 {
1088         struct inode *inode;
1089         struct dentry *root;
1090         struct net *net = data;
1091         struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
1092         int err;
1093
1094         sb->s_blocksize = PAGE_CACHE_SIZE;
1095         sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
1096         sb->s_magic = RPCAUTH_GSSMAGIC;
1097         sb->s_op = &s_ops;
1098         sb->s_time_gran = 1;
1099
1100         inode = rpc_get_inode(sb, S_IFDIR | 0755);
1101         if (!inode)
1102                 return -ENOMEM;
1103         sb->s_root = root = d_alloc_root(inode);
1104         if (!root) {
1105                 iput(inode);
1106                 return -ENOMEM;
1107         }
1108         if (rpc_populate(root, files, RPCAUTH_lockd, RPCAUTH_RootEOF, NULL))
1109                 return -ENOMEM;
1110         dprintk("RPC:   sending pipefs MOUNT notification for net %p%s\n", net,
1111                                                                 NET_NAME(net));
1112         err = blocking_notifier_call_chain(&rpc_pipefs_notifier_list,
1113                                            RPC_PIPEFS_MOUNT,
1114                                            sb);
1115         if (err)
1116                 goto err_depopulate;
1117         sb->s_fs_info = get_net(net);
1118         sn->pipefs_sb = sb;
1119         return 0;
1120
1121 err_depopulate:
1122         blocking_notifier_call_chain(&rpc_pipefs_notifier_list,
1123                                            RPC_PIPEFS_UMOUNT,
1124                                            sb);
1125         __rpc_depopulate(root, files, RPCAUTH_lockd, RPCAUTH_RootEOF);
1126         return err;
1127 }
1128
1129 static struct dentry *
1130 rpc_mount(struct file_system_type *fs_type,
1131                 int flags, const char *dev_name, void *data)
1132 {
1133         return mount_ns(fs_type, flags, current->nsproxy->net_ns, rpc_fill_super);
1134 }
1135
1136 void rpc_kill_sb(struct super_block *sb)
1137 {
1138         struct net *net = sb->s_fs_info;
1139         struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
1140
1141         mutex_lock(&sn->pipefs_sb_lock);
1142         sn->pipefs_sb = NULL;
1143         mutex_unlock(&sn->pipefs_sb_lock);
1144         put_net(net);
1145         dprintk("RPC:   sending pipefs UMOUNT notification for net %p%s\n", net,
1146                                                                 NET_NAME(net));
1147         blocking_notifier_call_chain(&rpc_pipefs_notifier_list,
1148                                            RPC_PIPEFS_UMOUNT,
1149                                            sb);
1150         kill_litter_super(sb);
1151 }
1152
1153 static struct file_system_type rpc_pipe_fs_type = {
1154         .owner          = THIS_MODULE,
1155         .name           = "rpc_pipefs",
1156         .mount          = rpc_mount,
1157         .kill_sb        = rpc_kill_sb,
1158 };
1159
1160 static void
1161 init_once(void *foo)
1162 {
1163         struct rpc_inode *rpci = (struct rpc_inode *) foo;
1164
1165         inode_init_once(&rpci->vfs_inode);
1166         rpci->private = NULL;
1167         rpci->pipe = NULL;
1168 }
1169
1170 int register_rpc_pipefs(void)
1171 {
1172         int err;
1173
1174         rpc_inode_cachep = kmem_cache_create("rpc_inode_cache",
1175                                 sizeof(struct rpc_inode),
1176                                 0, (SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT|
1177                                                 SLAB_MEM_SPREAD),
1178                                 init_once);
1179         if (!rpc_inode_cachep)
1180                 return -ENOMEM;
1181         err = rpc_clients_notifier_register();
1182         if (err)
1183                 goto err_notifier;
1184         err = register_filesystem(&rpc_pipe_fs_type);
1185         if (err)
1186                 goto err_register;
1187         return 0;
1188
1189 err_register:
1190         rpc_clients_notifier_unregister();
1191 err_notifier:
1192         kmem_cache_destroy(rpc_inode_cachep);
1193         return err;
1194 }
1195
1196 void unregister_rpc_pipefs(void)
1197 {
1198         rpc_clients_notifier_unregister();
1199         kmem_cache_destroy(rpc_inode_cachep);
1200         unregister_filesystem(&rpc_pipe_fs_type);
1201 }
1202
1203 /* Make 'mount -t rpc_pipefs ...' autoload this module. */
1204 MODULE_ALIAS("rpc_pipefs");