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 <asm/uaccess.h>
  19 #include "os.h"
  20
  21 static struct inode *get_inode(struct super_block *, struct dentry *);
  22
  23 struct hppfs_data {
  24         struct list_head list;
  25         char contents[PAGE_SIZE - sizeof(struct list_head)];
  26 };
  27
  28 struct hppfs_private {
  29         struct file *proc_file;
  30         int host_fd;
  31         loff_t len;
  32         struct hppfs_data *contents;
  33 };
  34
  35 struct hppfs_inode_info {
  36         struct dentry *proc_dentry;
  37         struct inode vfs_inode;
  38 };
  39
  40 static inline struct hppfs_inode_info *HPPFS_I(struct inode *inode)
  41 {
  42         return container_of(inode, struct hppfs_inode_info, vfs_inode);
  43 }
  44
  45 #define HPPFS_SUPER_MAGIC 0xb00000ee
  46
  47 static const struct super_operations hppfs_sbops;
  48
  49 static int is_pid(struct dentry *dentry)
  50 {
  51         struct super_block *sb;
  52         int i;
  53
  54         sb = dentry->d_sb;
  55         if (dentry->d_parent != sb->s_root)
  56                 return 0;
  57
  58         for (i = 0; i < dentry->d_name.len; i++) {
  59                 if (!isdigit(dentry->d_name.name[i]))
  60                         return 0;
  61         }
  62         return 1;
  63 }
  64
  65 static char *dentry_name(struct dentry *dentry, int extra)
  66 {
  67         struct dentry *parent;
  68         char *root, *name;
  69         const char *seg_name;
  70         int len, seg_len;
  71
  72         len = 0;
  73         parent = dentry;
  74         while (parent->d_parent != parent) {
  75                 if (is_pid(parent))
  76                         len += strlen("pid") + 1;
  77                 else len += parent->d_name.len + 1;
  78                 parent = parent->d_parent;
  79         }
  80
  81         root = "proc";
  82         len += strlen(root);
  83         name = kmalloc(len + extra + 1, GFP_KERNEL);
  84         if (name == NULL)
  85                 return NULL;
  86
  87         name[len] = '\0';
  88         parent = dentry;
  89         while (parent->d_parent != parent) {
  90                 if (is_pid(parent)) {
  91                         seg_name = "pid";
  92                         seg_len = strlen("pid");
  93                 }
  94                 else {
  95                         seg_name = parent->d_name.name;
  96                         seg_len = parent->d_name.len;
  97                 }
  98
  99                 len -= seg_len + 1;
 100                 name[len] = '/';
 101                 strncpy(&name[len + 1], seg_name, seg_len);
 102                 parent = parent->d_parent;
 103         }
 104         strncpy(name, root, strlen(root));
 105         return name;
 106 }
 107
 108 static int file_removed(struct dentry *dentry, const char *file)
 109 {
 110         char *host_file;
 111         int extra, fd;
 112
 113         extra = 0;
 114         if (file != NULL)
 115                 extra += strlen(file) + 1;
 116
 117         host_file = dentry_name(dentry, extra + strlen("/remove"));
 118         if (host_file == NULL) {
 119                 printk(KERN_ERR "file_removed : allocation failed\n");
 120                 return -ENOMEM;
 121         }
 122
 123         if (file != NULL) {
 124                 strcat(host_file, "/");
 125                 strcat(host_file, file);
 126         }
 127         strcat(host_file, "/remove");
 128
 129         fd = os_open_file(host_file, of_read(OPENFLAGS()), 0);
 130         kfree(host_file);
 131         if (fd > 0) {
 132                 os_close_file(fd);
 133                 return 1;
 134         }
 135         return 0;
 136 }
 137
 138 static struct dentry *hppfs_lookup(struct inode *ino, struct dentry *dentry,
 139                                    struct nameidata *nd)
 140 {
 141         struct dentry *proc_dentry, *new, *parent;
 142         struct inode *inode;
 143         int err, deleted;
 144
 145         deleted = file_removed(dentry, NULL);
 146         if (deleted < 0)
 147                 return ERR_PTR(deleted);
 148         else if (deleted)
 149                 return ERR_PTR(-ENOENT);
 150
 151         err = -ENOMEM;
 152         parent = HPPFS_I(ino)->proc_dentry;
 153         mutex_lock(&parent->d_inode->i_mutex);
 154         proc_dentry = d_lookup(parent, &dentry->d_name);
 155         if (proc_dentry == NULL) {
 156                 proc_dentry = d_alloc(parent, &dentry->d_name);
 157                 if (proc_dentry == NULL) {
 158                         mutex_unlock(&parent->d_inode->i_mutex);
 159                         goto out;
 160                 }
 161                 new = (*parent->d_inode->i_op->lookup)(parent->d_inode,
 162                                                        proc_dentry, NULL);
 163                 if (new) {
 164                         dput(proc_dentry);
 165                         proc_dentry = new;
 166                 }
 167         }
 168         mutex_unlock(&parent->d_inode->i_mutex);
 169
 170         if (IS_ERR(proc_dentry))
 171                 return proc_dentry;
 172
 173         err = -ENOMEM;
 174         inode = get_inode(ino->i_sb, proc_dentry);
 175         if (!inode)
 176                 goto out_dput;
 177
 178         d_add(dentry, inode);
 179         return NULL;
 180
 181  out_dput:
 182         dput(proc_dentry);
 183  out:
 184         return ERR_PTR(err);
 185 }
 186
 187 static const struct inode_operations hppfs_file_iops = {
 188 };
 189
 190 static ssize_t read_proc(struct file *file, char __user *buf, ssize_t count,
 191                          loff_t *ppos, int is_user)
 192 {
 193         ssize_t (*read)(struct file *, char __user *, size_t, loff_t *);
 194         ssize_t n;
 195
 196         read = file->f_path.dentry->d_inode->i_fop->read;
 197
 198         if (!is_user)
 199                 set_fs(KERNEL_DS);
 200
 201         n = (*read)(file, buf, count, &file->f_pos);
 202
 203         if (!is_user)
 204                 set_fs(USER_DS);
 205
 206         if (ppos)
 207                 *ppos = file->f_pos;
 208         return n;
 209 }
 210
 211 static ssize_t hppfs_read_file(int fd, char __user *buf, ssize_t count)
 212 {
 213         ssize_t n;
 214         int cur, err;
 215         char *new_buf;
 216
 217         n = -ENOMEM;
 218         new_buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
 219         if (new_buf == NULL) {
 220                 printk(KERN_ERR "hppfs_read_file : kmalloc failed\n");
 221                 goto out;
 222         }
 223         n = 0;
 224         while (count > 0) {
 225                 cur = min_t(ssize_t, count, PAGE_SIZE);
 226                 err = os_read_file(fd, new_buf, cur);
 227                 if (err < 0) {
 228                         printk(KERN_ERR "hppfs_read : read failed, "
 229                                "errno = %d\n", err);
 230                         n = err;
 231                         goto out_free;
 232                 } else if (err == 0)
 233                         break;
 234
 235                 if (copy_to_user(buf, new_buf, err)) {
 236                         n = -EFAULT;
 237                         goto out_free;
 238                 }
 239                 n += err;
 240                 count -= err;
 241         }
 242  out_free:
 243         kfree(new_buf);
 244  out:
 245         return n;
 246 }
 247
 248 static ssize_t hppfs_read(struct file *file, char __user *buf, size_t count,
 249                           loff_t *ppos)
 250 {
 251         struct hppfs_private *hppfs = file->private_data;
 252         struct hppfs_data *data;
 253         loff_t off;
 254         int err;
 255
 256         if (hppfs->contents != NULL) {
 257                 int rem;
 258
 259                 if (*ppos >= hppfs->len)
 260                         return 0;
 261
 262                 data = hppfs->contents;
 263                 off = *ppos;
 264                 while (off >= sizeof(data->contents)) {
 265                         data = list_entry(data->list.next, struct hppfs_data,
 266                                           list);
 267                         off -= sizeof(data->contents);
 268                 }
 269
 270                 if (off + count > hppfs->len)
 271                         count = hppfs->len - off;
 272                 rem = copy_to_user(buf, &data->contents[off], count);
 273                 *ppos += count - rem;
 274                 if (rem > 0)
 275                         return -EFAULT;
 276         } else if (hppfs->host_fd != -1) {
 277                 err = os_seek_file(hppfs->host_fd, *ppos);
 278                 if (err) {
 279                         printk(KERN_ERR "hppfs_read : seek failed, "
 280                                "errno = %d\n", err);
 281                         return err;
 282                 }
 283                 err = hppfs_read_file(hppfs->host_fd, buf, count);
 284                 if (err < 0) {
 285                         printk(KERN_ERR "hppfs_read: read failed: %d\n", err);
 286                         return err;
 287                 }
 288                 count = err;
 289                 if (count > 0)
 290                         *ppos += count;
 291         }
 292         else count = read_proc(hppfs->proc_file, buf, count, ppos, 1);
 293
 294         return count;
 295 }
 296
 297 static ssize_t hppfs_write(struct file *file, const char __user *buf,
 298                            size_t len, loff_t *ppos)
 299 {
 300         struct hppfs_private *data = file->private_data;
 301         struct file *proc_file = data->proc_file;
 302         ssize_t (*write)(struct file *, const char __user *, size_t, loff_t *);
 303
 304         write = proc_file->f_path.dentry->d_inode->i_fop->write;
 305         return (*write)(proc_file, buf, len, ppos);
 306 }
 307
 308 static int open_host_sock(char *host_file, int *filter_out)
 309 {
 310         char *end;
 311         int fd;
 312
 313         end = &host_file[strlen(host_file)];
 314         strcpy(end, "/rw");
 315         *filter_out = 1;
 316         fd = os_connect_socket(host_file);
 317         if (fd > 0)
 318                 return fd;
 319
 320         strcpy(end, "/r");
 321         *filter_out = 0;
 322         fd = os_connect_socket(host_file);
 323         return fd;
 324 }
 325
 326 static void free_contents(struct hppfs_data *head)
 327 {
 328         struct hppfs_data *data;
 329         struct list_head *ele, *next;
 330
 331         if (head == NULL)
 332                 return;
 333
 334         list_for_each_safe(ele, next, &head->list) {
 335                 data = list_entry(ele, struct hppfs_data, list);
 336                 kfree(data);
 337         }
 338         kfree(head);
 339 }
 340
 341 static struct hppfs_data *hppfs_get_data(int fd, int filter,
 342                                          struct file *proc_file,
 343                                          struct file *hppfs_file,
 344                                          loff_t *size_out)
 345 {
 346         struct hppfs_data *data, *new, *head;
 347         int n, err;
 348
 349         err = -ENOMEM;
 350         data = kmalloc(sizeof(*data), GFP_KERNEL);
 351         if (data == NULL) {
 352                 printk(KERN_ERR "hppfs_get_data : head allocation failed\n");
 353                 goto failed;
 354         }
 355
 356         INIT_LIST_HEAD(&data->list);
 357
 358         head = data;
 359         *size_out = 0;
 360
 361         if (filter) {
 362                 while ((n = read_proc(proc_file, data->contents,
 363                                       sizeof(data->contents), NULL, 0)) > 0)
 364                         os_write_file(fd, data->contents, n);
 365                 err = os_shutdown_socket(fd, 0, 1);
 366                 if (err) {
 367                         printk(KERN_ERR "hppfs_get_data : failed to shut down "
 368                                "socket\n");
 369                         goto failed_free;
 370                 }
 371         }
 372         while (1) {
 373                 n = os_read_file(fd, data->contents, sizeof(data->contents));
 374                 if (n < 0) {
 375                         err = n;
 376                         printk(KERN_ERR "hppfs_get_data : read failed, "
 377                                "errno = %d\n", err);
 378                         goto failed_free;
 379                 } else if (n == 0)
 380                         break;
 381
 382                 *size_out += n;
 383
 384                 if (n < sizeof(data->contents))
 385                         break;
 386
 387                 new = kmalloc(sizeof(*data), GFP_KERNEL);
 388                 if (new == 0) {
 389                         printk(KERN_ERR "hppfs_get_data : data allocation "
 390                                "failed\n");
 391                         err = -ENOMEM;
 392                         goto failed_free;
 393                 }
 394
 395                 INIT_LIST_HEAD(&new->list);
 396                 list_add(&new->list, &data->list);
 397                 data = new;
 398         }
 399         return head;
 400
 401  failed_free:
 402         free_contents(head);
 403  failed:
 404         return ERR_PTR(err);
 405 }
 406
 407 static struct hppfs_private *hppfs_data(void)
 408 {
 409         struct hppfs_private *data;
 410
 411         data = kmalloc(sizeof(*data), GFP_KERNEL);
 412         if (data == NULL)
 413                 return data;
 414
 415         *data = ((struct hppfs_private ) { .host_fd             = -1,
 416                                            .len                 = -1,
 417                                            .contents            = NULL } );
 418         return data;
 419 }
 420
 421 static int file_mode(int fmode)
 422 {
 423         if (fmode == (FMODE_READ | FMODE_WRITE))
 424                 return O_RDWR;
 425         if (fmode == FMODE_READ)
 426                 return O_RDONLY;
 427         if (fmode == FMODE_WRITE)
 428                 return O_WRONLY;
 429         return 0;
 430 }
 431
 432 static int hppfs_open(struct inode *inode, struct file *file)
 433 {
 434         const struct cred *cred = file->f_cred;
 435         struct hppfs_private *data;
 436         struct vfsmount *proc_mnt;
 437         struct dentry *proc_dentry;
 438         char *host_file;
 439         int err, fd, type, filter;
 440
 441         err = -ENOMEM;
 442         data = hppfs_data();
 443         if (data == NULL)
 444                 goto out;
 445
 446         host_file = dentry_name(file->f_path.dentry, strlen("/rw"));
 447         if (host_file == NULL)
 448                 goto out_free2;
 449
 450         proc_dentry = HPPFS_I(inode)->proc_dentry;
 451         proc_mnt = inode->i_sb->s_fs_info;
 452
 453         /* XXX This isn't closed anywhere */
 454         data->proc_file = dentry_open(dget(proc_dentry), mntget(proc_mnt),
 455                                       file_mode(file->f_mode), cred);
 456         err = PTR_ERR(data->proc_file);
 457         if (IS_ERR(data->proc_file))
 458                 goto out_free1;
 459
 460         type = os_file_type(host_file);
 461         if (type == OS_TYPE_FILE) {
 462                 fd = os_open_file(host_file, of_read(OPENFLAGS()), 0);
 463                 if (fd >= 0)
 464                         data->host_fd = fd;
 465                 else
 466                         printk(KERN_ERR "hppfs_open : failed to open '%s', "
 467                                "errno = %d\n", host_file, -fd);
 468
 469                 data->contents = NULL;
 470         } else if (type == OS_TYPE_DIR) {
 471                 fd = open_host_sock(host_file, &filter);
 472                 if (fd > 0) {
 473                         data->contents = hppfs_get_data(fd, filter,
 474                                                         data->proc_file,
 475                                                         file, &data->len);
 476                         if (!IS_ERR(data->contents))
 477                                 data->host_fd = fd;
 478                 } else
 479                         printk(KERN_ERR "hppfs_open : failed to open a socket "
 480                                "in '%s', errno = %d\n", host_file, -fd);
 481         }
 482         kfree(host_file);
 483
 484         file->private_data = data;
 485         return 0;
 486
 487  out_free1:
 488         kfree(host_file);
 489  out_free2:
 490         free_contents(data->contents);
 491         kfree(data);
 492  out:
 493         return err;
 494 }
 495
 496 static int hppfs_dir_open(struct inode *inode, struct file *file)
 497 {
 498         const struct cred *cred = file->f_cred;
 499         struct hppfs_private *data;
 500         struct vfsmount *proc_mnt;
 501         struct dentry *proc_dentry;
 502         int err;
 503
 504         err = -ENOMEM;
 505         data = hppfs_data();
 506         if (data == NULL)
 507                 goto out;
 508
 509         proc_dentry = HPPFS_I(inode)->proc_dentry;
 510         proc_mnt = inode->i_sb->s_fs_info;
 511         data->proc_file = dentry_open(dget(proc_dentry), mntget(proc_mnt),
 512                                       file_mode(file->f_mode), cred);
 513         err = PTR_ERR(data->proc_file);
 514         if (IS_ERR(data->proc_file))
 515                 goto out_free;
 516
 517         file->private_data = data;
 518         return 0;
 519
 520  out_free:
 521         kfree(data);
 522  out:
 523         return err;
 524 }
 525
 526 static loff_t hppfs_llseek(struct file *file, loff_t off, int where)
 527 {
 528         struct hppfs_private *data = file->private_data;
 529         struct file *proc_file = data->proc_file;
 530         loff_t (*llseek)(struct file *, loff_t, int);
 531         loff_t ret;
 532
 533         llseek = proc_file->f_path.dentry->d_inode->i_fop->llseek;
 534         if (llseek != NULL) {
 535                 ret = (*llseek)(proc_file, off, where);
 536                 if (ret < 0)
 537                         return ret;
 538         }
 539
 540         return default_llseek(file, off, where);
 541 }
 542
 543 static const struct file_operations hppfs_file_fops = {
 544         .owner          = NULL,
 545         .llseek         = hppfs_llseek,
 546         .read           = hppfs_read,
 547         .write          = hppfs_write,
 548         .open           = hppfs_open,
 549 };
 550
 551 struct hppfs_dirent {
 552         void *vfs_dirent;
 553         filldir_t filldir;
 554         struct dentry *dentry;
 555 };
 556
 557 static int hppfs_filldir(void *d, const char *name, int size,
 558                          loff_t offset, u64 inode, unsigned int type)
 559 {
 560         struct hppfs_dirent *dirent = d;
 561
 562         if (file_removed(dirent->dentry, name))
 563                 return 0;
 564
 565         return (*dirent->filldir)(dirent->vfs_dirent, name, size, offset,
 566                                   inode, type);
 567 }
 568
 569 static int hppfs_readdir(struct file *file, void *ent, filldir_t filldir)
 570 {
 571         struct hppfs_private *data = file->private_data;
 572         struct file *proc_file = data->proc_file;
 573         int (*readdir)(struct file *, void *, filldir_t);
 574         struct hppfs_dirent dirent = ((struct hppfs_dirent)
 575                                       { .vfs_dirent     = ent,
 576                                         .filldir        = filldir,
 577                                         .dentry         = file->f_path.dentry
 578                                       });
 579         int err;
 580
 581         readdir = proc_file->f_path.dentry->d_inode->i_fop->readdir;
 582
 583         proc_file->f_pos = file->f_pos;
 584         err = (*readdir)(proc_file, &dirent, hppfs_filldir);
 585         file->f_pos = proc_file->f_pos;
 586
 587         return err;
 588 }
 589
 590 static int hppfs_fsync(struct file *file, struct dentry *dentry, int datasync)
 591 {
 592         return 0;
 593 }
 594
 595 static const struct file_operations hppfs_dir_fops = {
 596         .owner          = NULL,
 597         .readdir        = hppfs_readdir,
 598         .open           = hppfs_dir_open,
 599         .fsync          = hppfs_fsync,
 600 };
 601
 602 static int hppfs_statfs(struct dentry *dentry, struct kstatfs *sf)
 603 {
 604         sf->f_blocks = 0;
 605         sf->f_bfree = 0;
 606         sf->f_bavail = 0;
 607         sf->f_files = 0;
 608         sf->f_ffree = 0;
 609         sf->f_type = HPPFS_SUPER_MAGIC;
 610         return 0;
 611 }
 612
 613 static struct inode *hppfs_alloc_inode(struct super_block *sb)
 614 {
 615         struct hppfs_inode_info *hi;
 616
 617         hi = kmalloc(sizeof(*hi), GFP_KERNEL);
 618         if (!hi)
 619                 return NULL;
 620
 621         hi->proc_dentry = NULL;
 622         inode_init_once(&hi->vfs_inode);
 623         return &hi->vfs_inode;
 624 }
 625
 626 void hppfs_delete_inode(struct inode *ino)
 627 {
 628         dput(HPPFS_I(ino)->proc_dentry);
 629         mntput(ino->i_sb->s_fs_info);
 630
 631         clear_inode(ino);
 632 }
 633
 634 static void hppfs_destroy_inode(struct inode *inode)
 635 {
 636         kfree(HPPFS_I(inode));
 637 }
 638
 639 static const struct super_operations hppfs_sbops = {
 640         .alloc_inode    = hppfs_alloc_inode,
 641         .destroy_inode  = hppfs_destroy_inode,
 642         .delete_inode   = hppfs_delete_inode,
 643         .statfs         = hppfs_statfs,
 644 };
 645
 646 static int hppfs_readlink(struct dentry *dentry, char __user *buffer,
 647                           int buflen)
 648 {
 649         struct dentry *proc_dentry = HPPFS_I(dentry->d_inode)->proc_dentry;
 650         return proc_dentry->d_inode->i_op->readlink(proc_dentry, buffer,
 651                                                     buflen);
 652 }
 653
 654 static void *hppfs_follow_link(struct dentry *dentry, struct nameidata *nd)
 655 {
 656         struct dentry *proc_dentry = HPPFS_I(dentry->d_inode)->proc_dentry;
 657
 658         return proc_dentry->d_inode->i_op->follow_link(proc_dentry, nd);
 659 }
 660
 661 static void hppfs_put_link(struct dentry *dentry, struct nameidata *nd,
 662                            void *cookie)
 663 {
 664         struct dentry *proc_dentry = HPPFS_I(dentry->d_inode)->proc_dentry;
 665
 666         if (proc_dentry->d_inode->i_op->put_link)
 667                 proc_dentry->d_inode->i_op->put_link(proc_dentry, nd, cookie);
 668 }
 669
 670 static const struct inode_operations hppfs_dir_iops = {
 671         .lookup         = hppfs_lookup,
 672 };
 673
 674 static const struct inode_operations hppfs_link_iops = {
 675         .readlink       = hppfs_readlink,
 676         .follow_link    = hppfs_follow_link,
 677         .put_link       = hppfs_put_link,
 678 };
 679
 680 static struct inode *get_inode(struct super_block *sb, struct dentry *dentry)
 681 {
 682         struct inode *proc_ino = dentry->d_inode;
 683         struct inode *inode = new_inode(sb);
 684
 685         if (!inode)
 686                 return ERR_PTR(-ENOMEM);
 687
 688         if (S_ISDIR(dentry->d_inode->i_mode)) {
 689                 inode->i_op = &hppfs_dir_iops;
 690                 inode->i_fop = &hppfs_dir_fops;
 691         } else if (S_ISLNK(dentry->d_inode->i_mode)) {
 692                 inode->i_op = &hppfs_link_iops;
 693                 inode->i_fop = &hppfs_file_fops;
 694         } else {
 695                 inode->i_op = &hppfs_file_iops;
 696                 inode->i_fop = &hppfs_file_fops;
 697         }
 698
 699         HPPFS_I(inode)->proc_dentry = dget(dentry);
 700
 701         inode->i_uid = proc_ino->i_uid;
 702         inode->i_gid = proc_ino->i_gid;
 703         inode->i_atime = proc_ino->i_atime;
 704         inode->i_mtime = proc_ino->i_mtime;
 705         inode->i_ctime = proc_ino->i_ctime;
 706         inode->i_ino = proc_ino->i_ino;
 707         inode->i_mode = proc_ino->i_mode;
 708         inode->i_nlink = proc_ino->i_nlink;
 709         inode->i_size = proc_ino->i_size;
 710         inode->i_blocks = proc_ino->i_blocks;
 711
 712         return inode;
 713 }
 714
 715 static int hppfs_fill_super(struct super_block *sb, void *d, int silent)
 716 {
 717         struct inode *root_inode;
 718         struct vfsmount *proc_mnt;
 719         int err = -ENOENT;
 720
 721         proc_mnt = mntget(current->nsproxy->pid_ns->proc_mnt);
 722         if (IS_ERR(proc_mnt))
 723                 goto out;
 724
 725         sb->s_blocksize = 1024;
 726         sb->s_blocksize_bits = 10;
 727         sb->s_magic = HPPFS_SUPER_MAGIC;
 728         sb->s_op = &hppfs_sbops;
 729         sb->s_fs_info = proc_mnt;
 730
 731         err = -ENOMEM;
 732         root_inode = get_inode(sb, proc_mnt->mnt_sb->s_root);
 733         if (!root_inode)
 734                 goto out_mntput;
 735
 736         sb->s_root = d_alloc_root(root_inode);
 737         if (!sb->s_root)
 738                 goto out_iput;
 739
 740         return 0;
 741
 742  out_iput:
 743         iput(root_inode);
 744  out_mntput:
 745         mntput(proc_mnt);
 746  out:
 747         return(err);
 748 }
 749
 750 static int hppfs_read_super(struct file_system_type *type,
 751                             int flags, const char *dev_name,
 752                             void *data, struct vfsmount *mnt)
 753 {
 754         return get_sb_nodev(type, flags, data, hppfs_fill_super, mnt);
 755 }
 756
 757 static struct file_system_type hppfs_type = {
 758         .owner          = THIS_MODULE,
 759         .name           = "hppfs",
 760         .get_sb         = hppfs_read_super,
 761         .kill_sb        = kill_anon_super,
 762         .fs_flags       = 0,
 763 };
 764
 765 static int __init init_hppfs(void)
 766 {
 767         return register_filesystem(&hppfs_type);
 768 }
 769
 770 static void __exit exit_hppfs(void)
 771 {
 772         unregister_filesystem(&hppfs_type);
 773 }
 774
 775 module_init(init_hppfs)
 776 module_exit(exit_hppfs)
 777 MODULE_LICENSE("GPL");