fs/hppfs/hppfs.c

   1 /*
   2  * Copyright (C) 2002 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
   3  * Licensed under the GPL
   4  */
   5
   6 #include <linux/ctype.h>
   7 #include <linux/dcache.h>
   8 #include <linux/file.h>
   9 #include <linux/fs.h>
  10 #include <linux/init.h>
  11 #include <linux/kernel.h>
  12 #include <linux/list.h>
  13 #include <linux/module.h>
  14 #include <linux/mount.h>
  15 #include <linux/slab.h>
  16 #include <linux/statfs.h>
  17 #include <linux/types.h>
  18 #include <linux/pid_namespace.h>
  19 #include <asm/uaccess.h>
  20 #include "os.h"
  21
  22 static struct inode *get_inode(struct super_block *, struct dentry *);
  23
  24 struct hppfs_data {
  25         struct list_head list;
  26         char contents[PAGE_SIZE - sizeof(struct list_head)];
  27 };
  28
  29 struct hppfs_private {
  30         struct file *proc_file;
  31         int host_fd;
  32         loff_t len;
  33         struct hppfs_data *contents;
  34 };
  35
  36 struct hppfs_inode_info {
  37         struct dentry *proc_dentry;
  38         struct inode vfs_inode;
  39 };
  40
  41 static inline struct hppfs_inode_info *HPPFS_I(struct inode *inode)
  42 {
  43         return container_of(inode, struct hppfs_inode_info, vfs_inode);
  44 }
  45
  46 #define HPPFS_SUPER_MAGIC 0xb00000ee
  47
  48 static const struct super_operations hppfs_sbops;
  49
  50 static int is_pid(struct dentry *dentry)
  51 {
  52         struct super_block *sb;
  53         int i;
  54
  55         sb = dentry->d_sb;
  56         if (dentry->d_parent != sb->s_root)
  57                 return 0;
  58
  59         for (i = 0; i < dentry->d_name.len; i++) {
  60                 if (!isdigit(dentry->d_name.name[i]))
  61                         return 0;
  62         }
  63         return 1;
  64 }
  65
  66 static char *dentry_name(struct dentry *dentry, int extra)
  67 {
  68         struct dentry *parent;
  69         char *root, *name;
  70         const char *seg_name;
  71         int len, seg_len;
  72
  73         len = 0;
  74         parent = dentry;
  75         while (parent->d_parent != parent) {
  76                 if (is_pid(parent))
  77                         len += strlen("pid") + 1;
  78                 else len += parent->d_name.len + 1;
  79                 parent = parent->d_parent;
  80         }
  81
  82         root = "proc";
  83         len += strlen(root);
  84         name = kmalloc(len + extra + 1, GFP_KERNEL);
  85         if (name == NULL)
  86                 return NULL;
  87
  88         name[len] = '\0';
  89         parent = dentry;
  90         while (parent->d_parent != parent) {
  91                 if (is_pid(parent)) {
  92                         seg_name = "pid";
  93                         seg_len = strlen("pid");
  94                 }
  95                 else {
  96                         seg_name = parent->d_name.name;
  97                         seg_len = parent->d_name.len;
  98                 }
  99
 100                 len -= seg_len + 1;
 101                 name[len] = '/';
 102                 strncpy(&name[len + 1], seg_name, seg_len);
 103                 parent = parent->d_parent;
 104         }
 105         strncpy(name, root, strlen(root));
 106         return name;
 107 }
 108
 109 static int file_removed(struct dentry *dentry, const char *file)
 110 {
 111         char *host_file;
 112         int extra, fd;
 113
 114         extra = 0;
 115         if (file != NULL)
 116                 extra += strlen(file) + 1;
 117
 118         host_file = dentry_name(dentry, extra + strlen("/remove"));
 119         if (host_file == NULL) {
 120                 printk(KERN_ERR "file_removed : allocation failed\n");
 121                 return -ENOMEM;
 122         }
 123
 124         if (file != NULL) {
 125                 strcat(host_file, "/");
 126                 strcat(host_file, file);
 127         }
 128         strcat(host_file, "/remove");
 129
 130         fd = os_open_file(host_file, of_read(OPENFLAGS()), 0);
 131         kfree(host_file);
 132         if (fd > 0) {
 133                 os_close_file(fd);
 134                 return 1;
 135         }
 136         return 0;
 137 }
 138
 139 static struct dentry *hppfs_lookup(struct inode *ino, struct dentry *dentry,
 140                                    struct nameidata *nd)
 141 {
 142         struct dentry *proc_dentry, *parent;
 143         struct qstr *name = &dentry->d_name;
 144         struct inode *inode;
 145         int err, deleted;
 146
 147         deleted = file_removed(dentry, NULL);
 148         if (deleted < 0)
 149                 return ERR_PTR(deleted);
 150         else if (deleted)
 151                 return ERR_PTR(-ENOENT);
 152
 153         parent = HPPFS_I(ino)->proc_dentry;
 154         mutex_lock(&parent->d_inode->i_mutex);
 155         proc_dentry = lookup_one_len(name->name, parent, name->len);
 156         mutex_unlock(&parent->d_inode->i_mutex);
 157
 158         if (IS_ERR(proc_dentry))
 159                 return proc_dentry;
 160
 161         err = -ENOMEM;
 162         inode = get_inode(ino->i_sb, proc_dentry);
 163         if (!inode)
 164                 goto out;
 165
 166         d_add(dentry, inode);
 167         return NULL;
 168
 169  out:
 170         return ERR_PTR(err);
 171 }
 172
 173 static const struct inode_operations hppfs_file_iops = {
 174 };
 175
 176 static ssize_t read_proc(struct file *file, char __user *buf, ssize_t count,
 177                          loff_t *ppos, int is_user)
 178 {
 179         ssize_t (*read)(struct file *, char __user *, size_t, loff_t *);
 180         ssize_t n;
 181
 182         read = file->f_path.dentry->d_inode->i_fop->read;
 183
 184         if (!is_user)
 185                 set_fs(KERNEL_DS);
 186
 187         n = (*read)(file, buf, count, &file->f_pos);
 188
 189         if (!is_user)
 190                 set_fs(USER_DS);
 191
 192         if (ppos)
 193                 *ppos = file->f_pos;
 194         return n;
 195 }
 196
 197 static ssize_t hppfs_read_file(int fd, char __user *buf, ssize_t count)
 198 {
 199         ssize_t n;
 200         int cur, err;
 201         char *new_buf;
 202
 203         n = -ENOMEM;
 204         new_buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
 205         if (new_buf == NULL) {
 206                 printk(KERN_ERR "hppfs_read_file : kmalloc failed\n");
 207                 goto out;
 208         }
 209         n = 0;
 210         while (count > 0) {
 211                 cur = min_t(ssize_t, count, PAGE_SIZE);
 212                 err = os_read_file(fd, new_buf, cur);
 213                 if (err < 0) {
 214                         printk(KERN_ERR "hppfs_read : read failed, "
 215                                "errno = %d\n", err);
 216                         n = err;
 217                         goto out_free;
 218                 } else if (err == 0)
 219                         break;
 220
 221                 if (copy_to_user(buf, new_buf, err)) {
 222                         n = -EFAULT;
 223                         goto out_free;
 224                 }
 225                 n += err;
 226                 count -= err;
 227         }
 228  out_free:
 229         kfree(new_buf);
 230  out:
 231         return n;
 232 }
 233
 234 static ssize_t hppfs_read(struct file *file, char __user *buf, size_t count,
 235                           loff_t *ppos)
 236 {
 237         struct hppfs_private *hppfs = file->private_data;
 238         struct hppfs_data *data;
 239         loff_t off;
 240         int err;
 241
 242         if (hppfs->contents != NULL) {
 243                 int rem;
 244
 245                 if (*ppos >= hppfs->len)
 246                         return 0;
 247
 248                 data = hppfs->contents;
 249                 off = *ppos;
 250                 while (off >= sizeof(data->contents)) {
 251                         data = list_entry(data->list.next, struct hppfs_data,
 252                                           list);
 253                         off -= sizeof(data->contents);
 254                 }
 255
 256                 if (off + count > hppfs->len)
 257                         count = hppfs->len - off;
 258                 rem = copy_to_user(buf, &data->contents[off], count);
 259                 *ppos += count - rem;
 260                 if (rem > 0)
 261                         return -EFAULT;
 262         } else if (hppfs->host_fd != -1) {
 263                 err = os_seek_file(hppfs->host_fd, *ppos);
 264                 if (err) {
 265                         printk(KERN_ERR "hppfs_read : seek failed, "
 266                                "errno = %d\n", err);
 267                         return err;
 268                 }
 269                 err = hppfs_read_file(hppfs->host_fd, buf, count);
 270                 if (err < 0) {
 271                         printk(KERN_ERR "hppfs_read: read failed: %d\n", err);
 272                         return err;
 273                 }
 274                 count = err;
 275                 if (count > 0)
 276                         *ppos += count;
 277         }
 278         else count = read_proc(hppfs->proc_file, buf, count, ppos, 1);
 279
 280         return count;
 281 }
 282
 283 static ssize_t hppfs_write(struct file *file, const char __user *buf,
 284                            size_t len, loff_t *ppos)
 285 {
 286         struct hppfs_private *data = file->private_data;
 287         struct file *proc_file = data->proc_file;
 288         ssize_t (*write)(struct file *, const char __user *, size_t, loff_t *);
 289
 290         write = proc_file->f_path.dentry->d_inode->i_fop->write;
 291         return (*write)(proc_file, buf, len, ppos);
 292 }
 293
 294 static int open_host_sock(char *host_file, int *filter_out)
 295 {
 296         char *end;
 297         int fd;
 298
 299         end = &host_file[strlen(host_file)];
 300         strcpy(end, "/rw");
 301         *filter_out = 1;
 302         fd = os_connect_socket(host_file);
 303         if (fd > 0)
 304                 return fd;
 305
 306         strcpy(end, "/r");
 307         *filter_out = 0;
 308         fd = os_connect_socket(host_file);
 309         return fd;
 310 }
 311
 312 static void free_contents(struct hppfs_data *head)
 313 {
 314         struct hppfs_data *data;
 315         struct list_head *ele, *next;
 316
 317         if (head == NULL)
 318                 return;
 319
 320         list_for_each_safe(ele, next, &head->list) {
 321                 data = list_entry(ele, struct hppfs_data, list);
 322                 kfree(data);
 323         }
 324         kfree(head);
 325 }
 326
 327 static struct hppfs_data *hppfs_get_data(int fd, int filter,
 328                                          struct file *proc_file,
 329                                          struct file *hppfs_file,
 330                                          loff_t *size_out)
 331 {
 332         struct hppfs_data *data, *new, *head;
 333         int n, err;
 334
 335         err = -ENOMEM;
 336         data = kmalloc(sizeof(*data), GFP_KERNEL);
 337         if (data == NULL) {
 338                 printk(KERN_ERR "hppfs_get_data : head allocation failed\n");
 339                 goto failed;
 340         }
 341
 342         INIT_LIST_HEAD(&data->list);
 343
 344         head = data;
 345         *size_out = 0;
 346
 347         if (filter) {
 348                 while ((n = read_proc(proc_file, data->contents,
 349                                       sizeof(data->contents), NULL, 0)) > 0)
 350                         os_write_file(fd, data->contents, n);
 351                 err = os_shutdown_socket(fd, 0, 1);
 352                 if (err) {
 353                         printk(KERN_ERR "hppfs_get_data : failed to shut down "
 354                                "socket\n");
 355                         goto failed_free;
 356                 }
 357         }
 358         while (1) {
 359                 n = os_read_file(fd, data->contents, sizeof(data->contents));
 360                 if (n < 0) {
 361                         err = n;
 362                         printk(KERN_ERR "hppfs_get_data : read failed, "
 363                                "errno = %d\n", err);
 364                         goto failed_free;
 365                 } else if (n == 0)
 366                         break;
 367
 368                 *size_out += n;
 369
 370                 if (n < sizeof(data->contents))
 371                         break;
 372
 373                 new = kmalloc(sizeof(*data), GFP_KERNEL);
 374                 if (new == 0) {
 375                         printk(KERN_ERR "hppfs_get_data : data allocation "
 376                                "failed\n");
 377                         err = -ENOMEM;
 378                         goto failed_free;
 379                 }
 380
 381                 INIT_LIST_HEAD(&new->list);
 382                 list_add(&new->list, &data->list);
 383                 data = new;
 384         }
 385         return head;
 386
 387  failed_free:
 388         free_contents(head);
 389  failed:
 390         return ERR_PTR(err);
 391 }
 392
 393 static struct hppfs_private *hppfs_data(void)
 394 {
 395         struct hppfs_private *data;
 396
 397         data = kmalloc(sizeof(*data), GFP_KERNEL);
 398         if (data == NULL)
 399                 return data;
 400
 401         *data = ((struct hppfs_private ) { .host_fd             = -1,
 402                                            .len                 = -1,
 403                                            .contents            = NULL } );
 404         return data;
 405 }
 406
 407 static int file_mode(int fmode)
 408 {
 409         if (fmode == (FMODE_READ | FMODE_WRITE))
 410                 return O_RDWR;
 411         if (fmode == FMODE_READ)
 412                 return O_RDONLY;
 413         if (fmode == FMODE_WRITE)
 414                 return O_WRONLY;
 415         return 0;
 416 }
 417
 418 static int hppfs_open(struct inode *inode, struct file *file)
 419 {
 420         const struct cred *cred = file->f_cred;
 421         struct hppfs_private *data;
 422         struct vfsmount *proc_mnt;
 423         struct dentry *proc_dentry;
 424         char *host_file;
 425         int err, fd, type, filter;
 426
 427         err = -ENOMEM;
 428         data = hppfs_data();
 429         if (data == NULL)
 430                 goto out;
 431
 432         host_file = dentry_name(file->f_path.dentry, strlen("/rw"));
 433         if (host_file == NULL)
 434                 goto out_free2;
 435
 436         proc_dentry = HPPFS_I(inode)->proc_dentry;
 437         proc_mnt = inode->i_sb->s_fs_info;
 438
 439         /* XXX This isn't closed anywhere */
 440         data->proc_file = dentry_open(dget(proc_dentry), mntget(proc_mnt),
 441                                       file_mode(file->f_mode), cred);
 442         err = PTR_ERR(data->proc_file);
 443         if (IS_ERR(data->proc_file))
 444                 goto out_free1;
 445
 446         type = os_file_type(host_file);
 447         if (type == OS_TYPE_FILE) {
 448                 fd = os_open_file(host_file, of_read(OPENFLAGS()), 0);
 449                 if (fd >= 0)
 450                         data->host_fd = fd;
 451                 else
 452                         printk(KERN_ERR "hppfs_open : failed to open '%s', "
 453                                "errno = %d\n", host_file, -fd);
 454
 455                 data->contents = NULL;
 456         } else if (type == OS_TYPE_DIR) {
 457                 fd = open_host_sock(host_file, &filter);
 458                 if (fd > 0) {
 459                         data->contents = hppfs_get_data(fd, filter,
 460                                                         data->proc_file,
 461                                                         file, &data->len);
 462                         if (!IS_ERR(data->contents))
 463                                 data->host_fd = fd;
 464                 } else
 465                         printk(KERN_ERR "hppfs_open : failed to open a socket "
 466                                "in '%s', errno = %d\n", host_file, -fd);
 467         }
 468         kfree(host_file);
 469
 470         file->private_data = data;
 471         return 0;
 472
 473  out_free1:
 474         kfree(host_file);
 475  out_free2:
 476         free_contents(data->contents);
 477         kfree(data);
 478  out:
 479         return err;
 480 }
 481
 482 static int hppfs_dir_open(struct inode *inode, struct file *file)
 483 {
 484         const struct cred *cred = file->f_cred;
 485         struct hppfs_private *data;
 486         struct vfsmount *proc_mnt;
 487         struct dentry *proc_dentry;
 488         int err;
 489
 490         err = -ENOMEM;
 491         data = hppfs_data();
 492         if (data == NULL)
 493                 goto out;
 494
 495         proc_dentry = HPPFS_I(inode)->proc_dentry;
 496         proc_mnt = inode->i_sb->s_fs_info;
 497         data->proc_file = dentry_open(dget(proc_dentry), mntget(proc_mnt),
 498                                       file_mode(file->f_mode), cred);
 499         err = PTR_ERR(data->proc_file);
 500         if (IS_ERR(data->proc_file))
 501                 goto out_free;
 502
 503         file->private_data = data;
 504         return 0;
 505
 506  out_free:
 507         kfree(data);
 508  out:
 509         return err;
 510 }
 511
 512 static loff_t hppfs_llseek(struct file *file, loff_t off, int where)
 513 {
 514         struct hppfs_private *data = file->private_data;
 515         struct file *proc_file = data->proc_file;
 516         loff_t (*llseek)(struct file *, loff_t, int);
 517         loff_t ret;
 518
 519         llseek = proc_file->f_path.dentry->d_inode->i_fop->llseek;
 520         if (llseek != NULL) {
 521                 ret = (*llseek)(proc_file, off, where);
 522                 if (ret < 0)
 523                         return ret;
 524         }
 525
 526         return default_llseek(file, off, where);
 527 }
 528
 529 static const struct file_operations hppfs_file_fops = {
 530         .owner          = NULL,
 531         .llseek         = hppfs_llseek,
 532         .read           = hppfs_read,
 533         .write          = hppfs_write,
 534         .open           = hppfs_open,
 535 };
 536
 537 struct hppfs_dirent {
 538         void *vfs_dirent;
 539         filldir_t filldir;
 540         struct dentry *dentry;
 541 };
 542
 543 static int hppfs_filldir(void *d, const char *name, int size,
 544                          loff_t offset, u64 inode, unsigned int type)
 545 {
 546         struct hppfs_dirent *dirent = d;
 547
 548         if (file_removed(dirent->dentry, name))
 549                 return 0;
 550
 551         return (*dirent->filldir)(dirent->vfs_dirent, name, size, offset,
 552                                   inode, type);
 553 }
 554
 555 static int hppfs_readdir(struct file *file, void *ent, filldir_t filldir)
 556 {
 557         struct hppfs_private *data = file->private_data;
 558         struct file *proc_file = data->proc_file;
 559         int (*readdir)(struct file *, void *, filldir_t);
 560         struct hppfs_dirent dirent = ((struct hppfs_dirent)
 561                                       { .vfs_dirent     = ent,
 562                                         .filldir        = filldir,
 563                                         .dentry         = file->f_path.dentry
 564                                       });
 565         int err;
 566
 567         readdir = proc_file->f_path.dentry->d_inode->i_fop->readdir;
 568
 569         proc_file->f_pos = file->f_pos;
 570         err = (*readdir)(proc_file, &dirent, hppfs_filldir);
 571         file->f_pos = proc_file->f_pos;
 572
 573         return err;
 574 }
 575
 576 static int hppfs_fsync(struct file *file, loff_t start, loff_t end,
 577                        int datasync)
 578 {
 579         return filemap_write_and_wait_range(file->f_mapping, start, end);
 580 }
 581
 582 static const struct file_operations hppfs_dir_fops = {
 583         .owner          = NULL,
 584         .readdir        = hppfs_readdir,
 585         .open           = hppfs_dir_open,
 586         .fsync          = hppfs_fsync,
 587         .llseek         = default_llseek,
 588 };
 589
 590 static int hppfs_statfs(struct dentry *dentry, struct kstatfs *sf)
 591 {
 592         sf->f_blocks = 0;
 593         sf->f_bfree = 0;
 594         sf->f_bavail = 0;
 595         sf->f_files = 0;
 596         sf->f_ffree = 0;
 597         sf->f_type = HPPFS_SUPER_MAGIC;
 598         return 0;
 599 }
 600
 601 static struct inode *hppfs_alloc_inode(struct super_block *sb)
 602 {
 603         struct hppfs_inode_info *hi;
 604
 605         hi = kmalloc(sizeof(*hi), GFP_KERNEL);
 606         if (!hi)
 607                 return NULL;
 608
 609         hi->proc_dentry = NULL;
 610         inode_init_once(&hi->vfs_inode);
 611         return &hi->vfs_inode;
 612 }
 613
 614 void hppfs_evict_inode(struct inode *ino)
 615 {
 616         end_writeback(ino);
 617         dput(HPPFS_I(ino)->proc_dentry);
 618         mntput(ino->i_sb->s_fs_info);
 619 }
 620
 621 static void hppfs_i_callback(struct rcu_head *head)
 622 {
 623         struct inode *inode = container_of(head, struct inode, i_rcu);
 624         INIT_LIST_HEAD(&inode->i_dentry);
 625         kfree(HPPFS_I(inode));
 626 }
 627
 628 static void hppfs_destroy_inode(struct inode *inode)
 629 {
 630         call_rcu(&inode->i_rcu, hppfs_i_callback);
 631 }
 632
 633 static const struct super_operations hppfs_sbops = {
 634         .alloc_inode    = hppfs_alloc_inode,
 635         .destroy_inode  = hppfs_destroy_inode,
 636         .evict_inode    = hppfs_evict_inode,
 637         .statfs         = hppfs_statfs,
 638 };
 639
 640 static int hppfs_readlink(struct dentry *dentry, char __user *buffer,
 641                           int buflen)
 642 {
 643         struct dentry *proc_dentry = HPPFS_I(dentry->d_inode)->proc_dentry;
 644         return proc_dentry->d_inode->i_op->readlink(proc_dentry, buffer,
 645                                                     buflen);
 646 }
 647
 648 static void *hppfs_follow_link(struct dentry *dentry, struct nameidata *nd)
 649 {
 650         struct dentry *proc_dentry = HPPFS_I(dentry->d_inode)->proc_dentry;
 651
 652         return proc_dentry->d_inode->i_op->follow_link(proc_dentry, nd);
 653 }
 654
 655 static void hppfs_put_link(struct dentry *dentry, struct nameidata *nd,
 656                            void *cookie)
 657 {
 658         struct dentry *proc_dentry = HPPFS_I(dentry->d_inode)->proc_dentry;
 659
 660         if (proc_dentry->d_inode->i_op->put_link)
 661                 proc_dentry->d_inode->i_op->put_link(proc_dentry, nd, cookie);
 662 }
 663
 664 static const struct inode_operations hppfs_dir_iops = {
 665         .lookup         = hppfs_lookup,
 666 };
 667
 668 static const struct inode_operations hppfs_link_iops = {
 669         .readlink       = hppfs_readlink,
 670         .follow_link    = hppfs_follow_link,
 671         .put_link       = hppfs_put_link,
 672 };
 673
 674 static struct inode *get_inode(struct super_block *sb, struct dentry *dentry)
 675 {
 676         struct inode *proc_ino = dentry->d_inode;
 677         struct inode *inode = new_inode(sb);
 678
 679         if (!inode) {
 680                 dput(dentry);
 681                 return ERR_PTR(-ENOMEM);
 682         }
 683
 684         if (S_ISDIR(dentry->d_inode->i_mode)) {
 685                 inode->i_op = &hppfs_dir_iops;
 686                 inode->i_fop = &hppfs_dir_fops;
 687         } else if (S_ISLNK(dentry->d_inode->i_mode)) {
 688                 inode->i_op = &hppfs_link_iops;
 689                 inode->i_fop = &hppfs_file_fops;
 690         } else {
 691                 inode->i_op = &hppfs_file_iops;
 692                 inode->i_fop = &hppfs_file_fops;
 693         }
 694
 695         HPPFS_I(inode)->proc_dentry = dentry;
 696
 697         inode->i_uid = proc_ino->i_uid;
 698         inode->i_gid = proc_ino->i_gid;
 699         inode->i_atime = proc_ino->i_atime;
 700         inode->i_mtime = proc_ino->i_mtime;
 701         inode->i_ctime = proc_ino->i_ctime;
 702         inode->i_ino = proc_ino->i_ino;
 703         inode->i_mode = proc_ino->i_mode;
 704         inode->i_nlink = proc_ino->i_nlink;
 705         inode->i_size = proc_ino->i_size;
 706         inode->i_blocks = proc_ino->i_blocks;
 707
 708         return inode;
 709 }
 710
 711 static int hppfs_fill_super(struct super_block *sb, void *d, int silent)
 712 {
 713         struct inode *root_inode;
 714         struct vfsmount *proc_mnt;
 715         int err = -ENOENT;
 716
 717         proc_mnt = mntget(current->nsproxy->pid_ns->proc_mnt);
 718         if (IS_ERR(proc_mnt))
 719                 goto out;
 720
 721         sb->s_blocksize = 1024;
 722         sb->s_blocksize_bits = 10;
 723         sb->s_magic = HPPFS_SUPER_MAGIC;
 724         sb->s_op = &hppfs_sbops;
 725         sb->s_fs_info = proc_mnt;
 726
 727         err = -ENOMEM;
 728         root_inode = get_inode(sb, dget(proc_mnt->mnt_sb->s_root));
 729         if (!root_inode)
 730                 goto out_mntput;
 731
 732         sb->s_root = d_alloc_root(root_inode);
 733         if (!sb->s_root)
 734                 goto out_iput;
 735
 736         return 0;
 737
 738  out_iput:
 739         iput(root_inode);
 740  out_mntput:
 741         mntput(proc_mnt);
 742  out:
 743         return(err);
 744 }
 745
 746 static struct dentry *hppfs_read_super(struct file_system_type *type,
 747                             int flags, const char *dev_name,
 748                             void *data)
 749 {
 750         return mount_nodev(type, flags, data, hppfs_fill_super);
 751 }
 752
 753 static struct file_system_type hppfs_type = {
 754         .owner          = THIS_MODULE,
 755         .name           = "hppfs",
 756         .mount          = hppfs_read_super,
 757         .kill_sb        = kill_anon_super,
 758         .fs_flags       = 0,
 759 };
 760
 761 static int __init init_hppfs(void)
 762 {
 763         return register_filesystem(&hppfs_type);
 764 }
 765
 766 static void __exit exit_hppfs(void)
 767 {
 768         unregister_filesystem(&hppfs_type);
 769 }
 770
 771 module_init(init_hppfs)
 772 module_exit(exit_hppfs)
 773 MODULE_LICENSE("GPL");