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, *new, *parent;
 143         struct inode *inode;
 144         int err, deleted;
 145
 146         deleted = file_removed(dentry, NULL);
 147         if (deleted < 0)
 148                 return ERR_PTR(deleted);
 149         else if (deleted)
 150                 return ERR_PTR(-ENOENT);
 151
 152         err = -ENOMEM;
 153         parent = HPPFS_I(ino)->proc_dentry;
 154         mutex_lock(&parent->d_inode->i_mutex);
 155         proc_dentry = d_lookup(parent, &dentry->d_name);
 156         if (proc_dentry == NULL) {
 157                 proc_dentry = d_alloc(parent, &dentry->d_name);
 158                 if (proc_dentry == NULL) {
 159                         mutex_unlock(&parent->d_inode->i_mutex);
 160                         goto out;
 161                 }
 162                 new = (*parent->d_inode->i_op->lookup)(parent->d_inode,
 163                                                        proc_dentry, NULL);
 164                 if (new) {
 165                         dput(proc_dentry);
 166                         proc_dentry = new;
 167                 }
 168         }
 169         mutex_unlock(&parent->d_inode->i_mutex);
 170
 171         if (IS_ERR(proc_dentry))
 172                 return proc_dentry;
 173
 174         err = -ENOMEM;
 175         inode = get_inode(ino->i_sb, proc_dentry);
 176         if (!inode)
 177                 goto out_dput;
 178
 179         d_add(dentry, inode);
 180         return NULL;
 181
 182  out_dput:
 183         dput(proc_dentry);
 184  out:
 185         return ERR_PTR(err);
 186 }
 187
 188 static const struct inode_operations hppfs_file_iops = {
 189 };
 190
 191 static ssize_t read_proc(struct file *file, char __user *buf, ssize_t count,
 192                          loff_t *ppos, int is_user)
 193 {
 194         ssize_t (*read)(struct file *, char __user *, size_t, loff_t *);
 195         ssize_t n;
 196
 197         read = file->f_path.dentry->d_inode->i_fop->read;
 198
 199         if (!is_user)
 200                 set_fs(KERNEL_DS);
 201
 202         n = (*read)(file, buf, count, &file->f_pos);
 203
 204         if (!is_user)
 205                 set_fs(USER_DS);
 206
 207         if (ppos)
 208                 *ppos = file->f_pos;
 209         return n;
 210 }
 211
 212 static ssize_t hppfs_read_file(int fd, char __user *buf, ssize_t count)
 213 {
 214         ssize_t n;
 215         int cur, err;
 216         char *new_buf;
 217
 218         n = -ENOMEM;
 219         new_buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
 220         if (new_buf == NULL) {
 221                 printk(KERN_ERR "hppfs_read_file : kmalloc failed\n");
 222                 goto out;
 223         }
 224         n = 0;
 225         while (count > 0) {
 226                 cur = min_t(ssize_t, count, PAGE_SIZE);
 227                 err = os_read_file(fd, new_buf, cur);
 228                 if (err < 0) {
 229                         printk(KERN_ERR "hppfs_read : read failed, "
 230                                "errno = %d\n", err);
 231                         n = err;
 232                         goto out_free;
 233                 } else if (err == 0)
 234                         break;
 235
 236                 if (copy_to_user(buf, new_buf, err)) {
 237                         n = -EFAULT;
 238                         goto out_free;
 239                 }
 240                 n += err;
 241                 count -= err;
 242         }
 243  out_free:
 244         kfree(new_buf);
 245  out:
 246         return n;
 247 }
 248
 249 static ssize_t hppfs_read(struct file *file, char __user *buf, size_t count,
 250                           loff_t *ppos)
 251 {
 252         struct hppfs_private *hppfs = file->private_data;
 253         struct hppfs_data *data;
 254         loff_t off;
 255         int err;
 256
 257         if (hppfs->contents != NULL) {
 258                 int rem;
 259
 260                 if (*ppos >= hppfs->len)
 261                         return 0;
 262
 263                 data = hppfs->contents;
 264                 off = *ppos;
 265                 while (off >= sizeof(data->contents)) {
 266                         data = list_entry(data->list.next, struct hppfs_data,
 267                                           list);
 268                         off -= sizeof(data->contents);
 269                 }
 270
 271                 if (off + count > hppfs->len)
 272                         count = hppfs->len - off;
 273                 rem = copy_to_user(buf, &data->contents[off], count);
 274                 *ppos += count - rem;
 275                 if (rem > 0)
 276                         return -EFAULT;
 277         } else if (hppfs->host_fd != -1) {
 278                 err = os_seek_file(hppfs->host_fd, *ppos);
 279                 if (err) {
 280                         printk(KERN_ERR "hppfs_read : seek failed, "
 281                                "errno = %d\n", err);
 282                         return err;
 283                 }
 284                 err = hppfs_read_file(hppfs->host_fd, buf, count);
 285                 if (err < 0) {
 286                         printk(KERN_ERR "hppfs_read: read failed: %d\n", err);
 287                         return err;
 288                 }
 289                 count = err;
 290                 if (count > 0)
 291                         *ppos += count;
 292         }
 293         else count = read_proc(hppfs->proc_file, buf, count, ppos, 1);
 294
 295         return count;
 296 }
 297
 298 static ssize_t hppfs_write(struct file *file, const char __user *buf,
 299                            size_t len, loff_t *ppos)
 300 {
 301         struct hppfs_private *data = file->private_data;
 302         struct file *proc_file = data->proc_file;
 303         ssize_t (*write)(struct file *, const char __user *, size_t, loff_t *);
 304
 305         write = proc_file->f_path.dentry->d_inode->i_fop->write;
 306         return (*write)(proc_file, buf, len, ppos);
 307 }
 308
 309 static int open_host_sock(char *host_file, int *filter_out)
 310 {
 311         char *end;
 312         int fd;
 313
 314         end = &host_file[strlen(host_file)];
 315         strcpy(end, "/rw");
 316         *filter_out = 1;
 317         fd = os_connect_socket(host_file);
 318         if (fd > 0)
 319                 return fd;
 320
 321         strcpy(end, "/r");
 322         *filter_out = 0;
 323         fd = os_connect_socket(host_file);
 324         return fd;
 325 }
 326
 327 static void free_contents(struct hppfs_data *head)
 328 {
 329         struct hppfs_data *data;
 330         struct list_head *ele, *next;
 331
 332         if (head == NULL)
 333                 return;
 334
 335         list_for_each_safe(ele, next, &head->list) {
 336                 data = list_entry(ele, struct hppfs_data, list);
 337                 kfree(data);
 338         }
 339         kfree(head);
 340 }
 341
 342 static struct hppfs_data *hppfs_get_data(int fd, int filter,
 343                                          struct file *proc_file,
 344                                          struct file *hppfs_file,
 345                                          loff_t *size_out)
 346 {
 347         struct hppfs_data *data, *new, *head;
 348         int n, err;
 349
 350         err = -ENOMEM;
 351         data = kmalloc(sizeof(*data), GFP_KERNEL);
 352         if (data == NULL) {
 353                 printk(KERN_ERR "hppfs_get_data : head allocation failed\n");
 354                 goto failed;
 355         }
 356
 357         INIT_LIST_HEAD(&data->list);
 358
 359         head = data;
 360         *size_out = 0;
 361
 362         if (filter) {
 363                 while ((n = read_proc(proc_file, data->contents,
 364                                       sizeof(data->contents), NULL, 0)) > 0)
 365                         os_write_file(fd, data->contents, n);
 366                 err = os_shutdown_socket(fd, 0, 1);
 367                 if (err) {
 368                         printk(KERN_ERR "hppfs_get_data : failed to shut down "
 369                                "socket\n");
 370                         goto failed_free;
 371                 }
 372         }
 373         while (1) {
 374                 n = os_read_file(fd, data->contents, sizeof(data->contents));
 375                 if (n < 0) {
 376                         err = n;
 377                         printk(KERN_ERR "hppfs_get_data : read failed, "
 378                                "errno = %d\n", err);
 379                         goto failed_free;
 380                 } else if (n == 0)
 381                         break;
 382
 383                 *size_out += n;
 384
 385                 if (n < sizeof(data->contents))
 386                         break;
 387
 388                 new = kmalloc(sizeof(*data), GFP_KERNEL);
 389                 if (new == 0) {
 390                         printk(KERN_ERR "hppfs_get_data : data allocation "
 391                                "failed\n");
 392                         err = -ENOMEM;
 393                         goto failed_free;
 394                 }
 395
 396                 INIT_LIST_HEAD(&new->list);
 397                 list_add(&new->list, &data->list);
 398                 data = new;
 399         }
 400         return head;
 401
 402  failed_free:
 403         free_contents(head);
 404  failed:
 405         return ERR_PTR(err);
 406 }
 407
 408 static struct hppfs_private *hppfs_data(void)
 409 {
 410         struct hppfs_private *data;
 411
 412         data = kmalloc(sizeof(*data), GFP_KERNEL);
 413         if (data == NULL)
 414                 return data;
 415
 416         *data = ((struct hppfs_private ) { .host_fd             = -1,
 417                                            .len                 = -1,
 418                                            .contents            = NULL } );
 419         return data;
 420 }
 421
 422 static int file_mode(int fmode)
 423 {
 424         if (fmode == (FMODE_READ | FMODE_WRITE))
 425                 return O_RDWR;
 426         if (fmode == FMODE_READ)
 427                 return O_RDONLY;
 428         if (fmode == FMODE_WRITE)
 429                 return O_WRONLY;
 430         return 0;
 431 }
 432
 433 static int hppfs_open(struct inode *inode, struct file *file)
 434 {
 435         const struct cred *cred = file->f_cred;
 436         struct hppfs_private *data;
 437         struct vfsmount *proc_mnt;
 438         struct dentry *proc_dentry;
 439         char *host_file;
 440         int err, fd, type, filter;
 441
 442         err = -ENOMEM;
 443         data = hppfs_data();
 444         if (data == NULL)
 445                 goto out;
 446
 447         host_file = dentry_name(file->f_path.dentry, strlen("/rw"));
 448         if (host_file == NULL)
 449                 goto out_free2;
 450
 451         proc_dentry = HPPFS_I(inode)->proc_dentry;
 452         proc_mnt = inode->i_sb->s_fs_info;
 453
 454         /* XXX This isn't closed anywhere */
 455         data->proc_file = dentry_open(dget(proc_dentry), mntget(proc_mnt),
 456                                       file_mode(file->f_mode), cred);
 457         err = PTR_ERR(data->proc_file);
 458         if (IS_ERR(data->proc_file))
 459                 goto out_free1;
 460
 461         type = os_file_type(host_file);
 462         if (type == OS_TYPE_FILE) {
 463                 fd = os_open_file(host_file, of_read(OPENFLAGS()), 0);
 464                 if (fd >= 0)
 465                         data->host_fd = fd;
 466                 else
 467                         printk(KERN_ERR "hppfs_open : failed to open '%s', "
 468                                "errno = %d\n", host_file, -fd);
 469
 470                 data->contents = NULL;
 471         } else if (type == OS_TYPE_DIR) {
 472                 fd = open_host_sock(host_file, &filter);
 473                 if (fd > 0) {
 474                         data->contents = hppfs_get_data(fd, filter,
 475                                                         data->proc_file,
 476                                                         file, &data->len);
 477                         if (!IS_ERR(data->contents))
 478                                 data->host_fd = fd;
 479                 } else
 480                         printk(KERN_ERR "hppfs_open : failed to open a socket "
 481                                "in '%s', errno = %d\n", host_file, -fd);
 482         }
 483         kfree(host_file);
 484
 485         file->private_data = data;
 486         return 0;
 487
 488  out_free1:
 489         kfree(host_file);
 490  out_free2:
 491         free_contents(data->contents);
 492         kfree(data);
 493  out:
 494         return err;
 495 }
 496
 497 static int hppfs_dir_open(struct inode *inode, struct file *file)
 498 {
 499         const struct cred *cred = file->f_cred;
 500         struct hppfs_private *data;
 501         struct vfsmount *proc_mnt;
 502         struct dentry *proc_dentry;
 503         int err;
 504
 505         err = -ENOMEM;
 506         data = hppfs_data();
 507         if (data == NULL)
 508                 goto out;
 509
 510         proc_dentry = HPPFS_I(inode)->proc_dentry;
 511         proc_mnt = inode->i_sb->s_fs_info;
 512         data->proc_file = dentry_open(dget(proc_dentry), mntget(proc_mnt),
 513                                       file_mode(file->f_mode), cred);
 514         err = PTR_ERR(data->proc_file);
 515         if (IS_ERR(data->proc_file))
 516                 goto out_free;
 517
 518         file->private_data = data;
 519         return 0;
 520
 521  out_free:
 522         kfree(data);
 523  out:
 524         return err;
 525 }
 526
 527 static loff_t hppfs_llseek(struct file *file, loff_t off, int where)
 528 {
 529         struct hppfs_private *data = file->private_data;
 530         struct file *proc_file = data->proc_file;
 531         loff_t (*llseek)(struct file *, loff_t, int);
 532         loff_t ret;
 533
 534         llseek = proc_file->f_path.dentry->d_inode->i_fop->llseek;
 535         if (llseek != NULL) {
 536                 ret = (*llseek)(proc_file, off, where);
 537                 if (ret < 0)
 538                         return ret;
 539         }
 540
 541         return default_llseek(file, off, where);
 542 }
 543
 544 static const struct file_operations hppfs_file_fops = {
 545         .owner          = NULL,
 546         .llseek         = hppfs_llseek,
 547         .read           = hppfs_read,
 548         .write          = hppfs_write,
 549         .open           = hppfs_open,
 550 };
 551
 552 struct hppfs_dirent {
 553         void *vfs_dirent;
 554         filldir_t filldir;
 555         struct dentry *dentry;
 556 };
 557
 558 static int hppfs_filldir(void *d, const char *name, int size,
 559                          loff_t offset, u64 inode, unsigned int type)
 560 {
 561         struct hppfs_dirent *dirent = d;
 562
 563         if (file_removed(dirent->dentry, name))
 564                 return 0;
 565
 566         return (*dirent->filldir)(dirent->vfs_dirent, name, size, offset,
 567                                   inode, type);
 568 }
 569
 570 static int hppfs_readdir(struct file *file, void *ent, filldir_t filldir)
 571 {
 572         struct hppfs_private *data = file->private_data;
 573         struct file *proc_file = data->proc_file;
 574         int (*readdir)(struct file *, void *, filldir_t);
 575         struct hppfs_dirent dirent = ((struct hppfs_dirent)
 576                                       { .vfs_dirent     = ent,
 577                                         .filldir        = filldir,
 578                                         .dentry         = file->f_path.dentry
 579                                       });
 580         int err;
 581
 582         readdir = proc_file->f_path.dentry->d_inode->i_fop->readdir;
 583
 584         proc_file->f_pos = file->f_pos;
 585         err = (*readdir)(proc_file, &dirent, hppfs_filldir);
 586         file->f_pos = proc_file->f_pos;
 587
 588         return err;
 589 }
 590
 591 static int hppfs_fsync(struct file *file, int datasync)
 592 {
 593         return 0;
 594 }
 595
 596 static const struct file_operations hppfs_dir_fops = {
 597         .owner          = NULL,
 598         .readdir        = hppfs_readdir,
 599         .open           = hppfs_dir_open,
 600         .fsync          = hppfs_fsync,
 601         .llseek         = default_llseek,
 602 };
 603
 604 static int hppfs_statfs(struct dentry *dentry, struct kstatfs *sf)
 605 {
 606         sf->f_blocks = 0;
 607         sf->f_bfree = 0;
 608         sf->f_bavail = 0;
 609         sf->f_files = 0;
 610         sf->f_ffree = 0;
 611         sf->f_type = HPPFS_SUPER_MAGIC;
 612         return 0;
 613 }
 614
 615 static struct inode *hppfs_alloc_inode(struct super_block *sb)
 616 {
 617         struct hppfs_inode_info *hi;
 618
 619         hi = kmalloc(sizeof(*hi), GFP_KERNEL);
 620         if (!hi)
 621                 return NULL;
 622
 623         hi->proc_dentry = NULL;
 624         inode_init_once(&hi->vfs_inode);
 625         return &hi->vfs_inode;
 626 }
 627
 628 void hppfs_evict_inode(struct inode *ino)
 629 {
 630         end_writeback(ino);
 631         dput(HPPFS_I(ino)->proc_dentry);
 632         mntput(ino->i_sb->s_fs_info);
 633 }
 634
 635 static void hppfs_destroy_inode(struct inode *inode)
 636 {
 637         kfree(HPPFS_I(inode));
 638 }
 639
 640 static const struct super_operations hppfs_sbops = {
 641         .alloc_inode    = hppfs_alloc_inode,
 642         .destroy_inode  = hppfs_destroy_inode,
 643         .evict_inode    = hppfs_evict_inode,
 644         .statfs         = hppfs_statfs,
 645 };
 646
 647 static int hppfs_readlink(struct dentry *dentry, char __user *buffer,
 648                           int buflen)
 649 {
 650         struct dentry *proc_dentry = HPPFS_I(dentry->d_inode)->proc_dentry;
 651         return proc_dentry->d_inode->i_op->readlink(proc_dentry, buffer,
 652                                                     buflen);
 653 }
 654
 655 static void *hppfs_follow_link(struct dentry *dentry, struct nameidata *nd)
 656 {
 657         struct dentry *proc_dentry = HPPFS_I(dentry->d_inode)->proc_dentry;
 658
 659         return proc_dentry->d_inode->i_op->follow_link(proc_dentry, nd);
 660 }
 661
 662 static void hppfs_put_link(struct dentry *dentry, struct nameidata *nd,
 663                            void *cookie)
 664 {
 665         struct dentry *proc_dentry = HPPFS_I(dentry->d_inode)->proc_dentry;
 666
 667         if (proc_dentry->d_inode->i_op->put_link)
 668                 proc_dentry->d_inode->i_op->put_link(proc_dentry, nd, cookie);
 669 }
 670
 671 static const struct inode_operations hppfs_dir_iops = {
 672         .lookup         = hppfs_lookup,
 673 };
 674
 675 static const struct inode_operations hppfs_link_iops = {
 676         .readlink       = hppfs_readlink,
 677         .follow_link    = hppfs_follow_link,
 678         .put_link       = hppfs_put_link,
 679 };
 680
 681 static struct inode *get_inode(struct super_block *sb, struct dentry *dentry)
 682 {
 683         struct inode *proc_ino = dentry->d_inode;
 684         struct inode *inode = new_inode(sb);
 685
 686         if (!inode)
 687                 return ERR_PTR(-ENOMEM);
 688
 689         if (S_ISDIR(dentry->d_inode->i_mode)) {
 690                 inode->i_op = &hppfs_dir_iops;
 691                 inode->i_fop = &hppfs_dir_fops;
 692         } else if (S_ISLNK(dentry->d_inode->i_mode)) {
 693                 inode->i_op = &hppfs_link_iops;
 694                 inode->i_fop = &hppfs_file_fops;
 695         } else {
 696                 inode->i_op = &hppfs_file_iops;
 697                 inode->i_fop = &hppfs_file_fops;
 698         }
 699
 700         HPPFS_I(inode)->proc_dentry = dget(dentry);
 701
 702         inode->i_uid = proc_ino->i_uid;
 703         inode->i_gid = proc_ino->i_gid;
 704         inode->i_atime = proc_ino->i_atime;
 705         inode->i_mtime = proc_ino->i_mtime;
 706         inode->i_ctime = proc_ino->i_ctime;
 707         inode->i_ino = proc_ino->i_ino;
 708         inode->i_mode = proc_ino->i_mode;
 709         inode->i_nlink = proc_ino->i_nlink;
 710         inode->i_size = proc_ino->i_size;
 711         inode->i_blocks = proc_ino->i_blocks;
 712
 713         return inode;
 714 }
 715
 716 static int hppfs_fill_super(struct super_block *sb, void *d, int silent)
 717 {
 718         struct inode *root_inode;
 719         struct vfsmount *proc_mnt;
 720         int err = -ENOENT;
 721
 722         proc_mnt = mntget(current->nsproxy->pid_ns->proc_mnt);
 723         if (IS_ERR(proc_mnt))
 724                 goto out;
 725
 726         sb->s_blocksize = 1024;
 727         sb->s_blocksize_bits = 10;
 728         sb->s_magic = HPPFS_SUPER_MAGIC;
 729         sb->s_op = &hppfs_sbops;
 730         sb->s_fs_info = proc_mnt;
 731
 732         err = -ENOMEM;
 733         root_inode = get_inode(sb, proc_mnt->mnt_sb->s_root);
 734         if (!root_inode)
 735                 goto out_mntput;
 736
 737         sb->s_root = d_alloc_root(root_inode);
 738         if (!sb->s_root)
 739                 goto out_iput;
 740
 741         return 0;
 742
 743  out_iput:
 744         iput(root_inode);
 745  out_mntput:
 746         mntput(proc_mnt);
 747  out:
 748         return(err);
 749 }
 750
 751 static struct dentry *hppfs_read_super(struct file_system_type *type,
 752                             int flags, const char *dev_name,
 753                             void *data)
 754 {
 755         return mount_nodev(type, flags, data, hppfs_fill_super);
 756 }
 757
 758 static struct file_system_type hppfs_type = {
 759         .owner          = THIS_MODULE,
 760         .name           = "hppfs",
 761         .mount          = hppfs_read_super,
 762         .kill_sb        = kill_anon_super,
 763         .fs_flags       = 0,
 764 };
 765
 766 static int __init init_hppfs(void)
 767 {
 768         return register_filesystem(&hppfs_type);
 769 }
 770
 771 static void __exit exit_hppfs(void)
 772 {
 773         unregister_filesystem(&hppfs_type);
 774 }
 775
 776 module_init(init_hppfs)
 777 module_exit(exit_hppfs)
 778 MODULE_LICENSE("GPL");