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