LXR linux/drivers/staging/autofs/root.c

   1/* -*- linux-c -*- --------------------------------------------------------- *
   2 *
   3 * drivers/staging/autofs/root.c
   4 *
   5 *  Copyright 1997-1998 Transmeta Corporation -- All Rights Reserved
   6 *
   7 * This file is part of the Linux kernel and is made available under
   8 * the terms of the GNU General Public License, version 2, or at your
   9 * option, any later version, incorporated herein by reference.
  10 *
  11 * ------------------------------------------------------------------------- */
  12
  13#include <linux/capability.h>
  14#include <linux/errno.h>
  15#include <linux/stat.h>
  16#include <linux/slab.h>
  17#include <linux/param.h>
  18#include <linux/time.h>
  19#include <linux/compat.h>
  20#include <linux/smp_lock.h>
  21#include "autofs_i.h"
  22
  23static int autofs_root_readdir(struct file *,void *,filldir_t);
  24static struct dentry *autofs_root_lookup(struct inode *,struct dentry *, struct nameidata *);
  25static int autofs_root_symlink(struct inode *,struct dentry *,const char *);
  26static int autofs_root_unlink(struct inode *,struct dentry *);
  27static int autofs_root_rmdir(struct inode *,struct dentry *);
  28static int autofs_root_mkdir(struct inode *,struct dentry *,int);
  29static long autofs_root_ioctl(struct file *,unsigned int,unsigned long);
  30#ifdef CONFIG_COMPAT
  31static long autofs_root_compat_ioctl(struct file *,unsigned int,unsigned long);
  32#endif
  33
  34const struct file_operations autofs_root_operations = {
  35        .llseek         = generic_file_llseek,
  36        .read           = generic_read_dir,
  37        .readdir        = autofs_root_readdir,
  38        .unlocked_ioctl = autofs_root_ioctl,
  39#ifdef CONFIG_COMPAT
  40        .compat_ioctl   = autofs_root_compat_ioctl,
  41#endif
  42};
  43
  44const struct inode_operations autofs_root_inode_operations = {
  45        .lookup         = autofs_root_lookup,
  46        .unlink         = autofs_root_unlink,
  47        .symlink        = autofs_root_symlink,
  48        .mkdir          = autofs_root_mkdir,
  49        .rmdir          = autofs_root_rmdir,
  50};
  51
  52static int autofs_root_readdir(struct file *filp, void *dirent, filldir_t filldir)
  53{
  54        struct autofs_dir_ent *ent = NULL;
  55        struct autofs_dirhash *dirhash;
  56        struct autofs_sb_info *sbi;
  57        struct inode * inode = filp->f_path.dentry->d_inode;
  58        off_t onr, nr;
  59
  60        lock_kernel();
  61
  62        sbi = autofs_sbi(inode->i_sb);
  63        dirhash = &sbi->dirhash;
  64        nr = filp->f_pos;
  65
  66        switch(nr)
  67        {
  68        case 0:
  69                if (filldir(dirent, ".", 1, nr, inode->i_ino, DT_DIR) < 0)
  70                        goto out;
  71                filp->f_pos = ++nr;
  72                /* fall through */
  73        case 1:
  74                if (filldir(dirent, "..", 2, nr, inode->i_ino, DT_DIR) < 0)
  75                        goto out;
  76                filp->f_pos = ++nr;
  77                /* fall through */
  78        default:
  79                while (onr = nr, ent = autofs_hash_enum(dirhash,&nr,ent)) {
  80                        if (!ent->dentry || d_mountpoint(ent->dentry)) {
  81                                if (filldir(dirent,ent->name,ent->len,onr,ent->ino,DT_UNKNOWN) < 0)
  82                                        goto out;
  83                                filp->f_pos = nr;
  84                        }
  85                }
  86                break;
  87        }
  88
  89out:
  90        unlock_kernel();
  91        return 0;
  92}
  93
  94static int try_to_fill_dentry(struct dentry *dentry, struct super_block *sb, struct autofs_sb_info *sbi)
  95{
  96        struct inode * inode;
  97        struct autofs_dir_ent *ent;
  98        int status = 0;
  99
 100        if (!(ent = autofs_hash_lookup(&sbi->dirhash, &dentry->d_name))) {
 101                do {
 102                        if (status && dentry->d_inode) {
 103                                if (status != -ENOENT)
 104                                        printk("autofs warning: lookup failure on positive dentry, status = %d, name = %s\n", status, dentry->d_name.name);
 105                                return 0; /* Try to get the kernel to invalidate this dentry */
 106                        }
 107
 108                        /* Turn this into a real negative dentry? */
 109                        if (status == -ENOENT) {
 110                                dentry->d_time = jiffies + AUTOFS_NEGATIVE_TIMEOUT;
 111                                dentry->d_flags &= ~DCACHE_AUTOFS_PENDING;
 112                                return 1;
 113                        } else if (status) {
 114                                /* Return a negative dentry, but leave it "pending" */
 115                                return 1;
 116                        }
 117                        status = autofs_wait(sbi, &dentry->d_name);
 118                } while (!(ent = autofs_hash_lookup(&sbi->dirhash, &dentry->d_name)));
 119        }
 120
 121        /* Abuse this field as a pointer to the directory entry, used to
 122           find the expire list pointers */
 123        dentry->d_time = (unsigned long) ent;
 124        
 125        if (!dentry->d_inode) {
 126                inode = autofs_iget(sb, ent->ino);
 127                if (IS_ERR(inode)) {
 128                        /* Failed, but leave pending for next time */
 129                        return 1;
 130                }
 131                dentry->d_inode = inode;
 132        }
 133
 134        /* If this is a directory that isn't a mount point, bitch at the
 135           daemon and fix it in user space */
 136        if (S_ISDIR(dentry->d_inode->i_mode) && !d_mountpoint(dentry)) {
 137                return !autofs_wait(sbi, &dentry->d_name);
 138        }
 139
 140        /* We don't update the usages for the autofs daemon itself, this
 141           is necessary for recursive autofs mounts */
 142        if (!autofs_oz_mode(sbi)) {
 143                autofs_update_usage(&sbi->dirhash,ent);
 144        }
 145
 146        dentry->d_flags &= ~DCACHE_AUTOFS_PENDING;
 147        return 1;
 148}
 149
 150
 151/*
 152 * Revalidate is called on every cache lookup.  Some of those
 153 * cache lookups may actually happen while the dentry is not
 154 * yet completely filled in, and revalidate has to delay such
 155 * lookups..
 156 */
 157static int autofs_revalidate(struct dentry *dentry, struct nameidata *nd)
 158{
 159        struct inode * dir;
 160        struct autofs_sb_info *sbi;
 161        struct autofs_dir_ent *ent;
 162        int res;
 163
 164        if (nd->flags & LOOKUP_RCU)
 165                return -ECHILD;
 166
 167        lock_kernel();
 168        dir = dentry->d_parent->d_inode;
 169        sbi = autofs_sbi(dir->i_sb);
 170
 171        /* Pending dentry */
 172        if (dentry->d_flags & DCACHE_AUTOFS_PENDING) {
 173                if (autofs_oz_mode(sbi))
 174                        res = 1;
 175                else
 176                        res = try_to_fill_dentry(dentry, dir->i_sb, sbi);
 177                unlock_kernel();
 178                return res;
 179        }
 180
 181        /* Negative dentry.. invalidate if "old" */
 182        if (!dentry->d_inode) {
 183                unlock_kernel();
 184                return (dentry->d_time - jiffies <= AUTOFS_NEGATIVE_TIMEOUT);
 185        }
 186                
 187        /* Check for a non-mountpoint directory */
 188        if (S_ISDIR(dentry->d_inode->i_mode) && !d_mountpoint(dentry)) {
 189                if (autofs_oz_mode(sbi))
 190                        res = 1;
 191                else
 192                        res = try_to_fill_dentry(dentry, dir->i_sb, sbi);
 193                unlock_kernel();
 194                return res;
 195        }
 196
 197        /* Update the usage list */
 198        if (!autofs_oz_mode(sbi)) {
 199                ent = (struct autofs_dir_ent *) dentry->d_time;
 200                if (ent)
 201                        autofs_update_usage(&sbi->dirhash,ent);
 202        }
 203        unlock_kernel();
 204        return 1;
 205}
 206
 207static const struct dentry_operations autofs_dentry_operations = {
 208        .d_revalidate   = autofs_revalidate,
 209};
 210
 211static struct dentry *autofs_root_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd)
 212{
 213        struct autofs_sb_info *sbi;
 214        int oz_mode;
 215
 216        DPRINTK(("autofs_root_lookup: name = "));
 217        lock_kernel();
 218        autofs_say(dentry->d_name.name,dentry->d_name.len);
 219
 220        if (dentry->d_name.len > NAME_MAX) {
 221                unlock_kernel();
 222                return ERR_PTR(-ENAMETOOLONG);/* File name too long to exist */
 223        }
 224
 225        sbi = autofs_sbi(dir->i_sb);
 226
 227        oz_mode = autofs_oz_mode(sbi);
 228        DPRINTK(("autofs_lookup: pid = %u, pgrp = %u, catatonic = %d, "
 229                                "oz_mode = %d\n", task_pid_nr(current),
 230                                task_pgrp_nr(current), sbi->catatonic,
 231                                oz_mode));
 232
 233        /*
 234         * Mark the dentry incomplete, but add it. This is needed so
 235         * that the VFS layer knows about the dentry, and we can count
 236         * on catching any lookups through the revalidate.
 237         *
 238         * Let all the hard work be done by the revalidate function that
 239         * needs to be able to do this anyway..
 240         *
 241         * We need to do this before we release the directory semaphore.
 242         */
 243        d_set_d_op(dentry, &autofs_dentry_operations);
 244        dentry->d_flags |= DCACHE_AUTOFS_PENDING;
 245        d_add(dentry, NULL);
 246
 247        mutex_unlock(&dir->i_mutex);
 248        autofs_revalidate(dentry, nd);
 249        mutex_lock(&dir->i_mutex);
 250
 251        /*
 252         * If we are still pending, check if we had to handle
 253         * a signal. If so we can force a restart..
 254         */
 255        if (dentry->d_flags & DCACHE_AUTOFS_PENDING) {
 256                /* See if we were interrupted */
 257                if (signal_pending(current)) {
 258                        sigset_t *sigset = &current->pending.signal;
 259                        if (sigismember (sigset, SIGKILL) ||
 260                            sigismember (sigset, SIGQUIT) ||
 261                            sigismember (sigset, SIGINT)) {
 262                                unlock_kernel();
 263                                return ERR_PTR(-ERESTARTNOINTR);
 264                        }
 265                }
 266        }
 267        unlock_kernel();
 268
 269        /*
 270         * If this dentry is unhashed, then we shouldn't honour this
 271         * lookup even if the dentry is positive.  Returning ENOENT here
 272         * doesn't do the right thing for all system calls, but it should
 273         * be OK for the operations we permit from an autofs.
 274         */
 275        if (dentry->d_inode && d_unhashed(dentry))
 276                return ERR_PTR(-ENOENT);
 277
 278        return NULL;
 279}
 280
 281static int autofs_root_symlink(struct inode *dir, struct dentry *dentry, const char *symname)
 282{
 283        struct autofs_sb_info *sbi = autofs_sbi(dir->i_sb);
 284        struct autofs_dirhash *dh = &sbi->dirhash;
 285        struct autofs_dir_ent *ent;
 286        unsigned int n;
 287        int slsize;
 288        struct autofs_symlink *sl;
 289        struct inode *inode;
 290
 291        DPRINTK(("autofs_root_symlink: %s <- ", symname));
 292        autofs_say(dentry->d_name.name,dentry->d_name.len);
 293
 294        lock_kernel();
 295        if (!autofs_oz_mode(sbi)) {
 296                unlock_kernel();
 297                return -EACCES;
 298        }
 299
 300        if (autofs_hash_lookup(dh, &dentry->d_name)) {
 301                unlock_kernel();
 302                return -EEXIST;
 303        }
 304
 305        n = find_first_zero_bit(sbi->symlink_bitmap,AUTOFS_MAX_SYMLINKS);
 306        if (n >= AUTOFS_MAX_SYMLINKS) {
 307                unlock_kernel();
 308                return -ENOSPC;
 309        }
 310
 311        set_bit(n,sbi->symlink_bitmap);
 312        sl = &sbi->symlink[n];
 313        sl->len = strlen(symname);
 314        sl->data = kmalloc(slsize = sl->len+1, GFP_KERNEL);
 315        if (!sl->data) {
 316                clear_bit(n,sbi->symlink_bitmap);
 317                unlock_kernel();
 318                return -ENOSPC;
 319        }
 320
 321        ent = kmalloc(sizeof(struct autofs_dir_ent), GFP_KERNEL);
 322        if (!ent) {
 323                kfree(sl->data);
 324                clear_bit(n,sbi->symlink_bitmap);
 325                unlock_kernel();
 326                return -ENOSPC;
 327        }
 328
 329        ent->name = kmalloc(dentry->d_name.len+1, GFP_KERNEL);
 330        if (!ent->name) {
 331                kfree(sl->data);
 332                kfree(ent);
 333                clear_bit(n,sbi->symlink_bitmap);
 334                unlock_kernel();
 335                return -ENOSPC;
 336        }
 337
 338        memcpy(sl->data,symname,slsize);
 339        sl->mtime = get_seconds();
 340
 341        ent->ino = AUTOFS_FIRST_SYMLINK + n;
 342        ent->hash = dentry->d_name.hash;
 343        memcpy(ent->name, dentry->d_name.name, 1+(ent->len = dentry->d_name.len));
 344        ent->dentry = NULL;     /* We don't keep the dentry for symlinks */
 345
 346        autofs_hash_insert(dh,ent);
 347
 348        inode = autofs_iget(dir->i_sb, ent->ino);
 349        if (IS_ERR(inode))
 350                return PTR_ERR(inode);
 351
 352        d_instantiate(dentry, inode);
 353        unlock_kernel();
 354        return 0;
 355}
 356
 357/*
 358 * NOTE!
 359 *
 360 * Normal filesystems would do a "d_delete()" to tell the VFS dcache
 361 * that the file no longer exists. However, doing that means that the
 362 * VFS layer can turn the dentry into a negative dentry, which we
 363 * obviously do not want (we're dropping the entry not because it
 364 * doesn't exist, but because it has timed out).
 365 *
 366 * Also see autofs_root_rmdir()..
 367 */
 368static int autofs_root_unlink(struct inode *dir, struct dentry *dentry)
 369{
 370        struct autofs_sb_info *sbi = autofs_sbi(dir->i_sb);
 371        struct autofs_dirhash *dh = &sbi->dirhash;
 372        struct autofs_dir_ent *ent;
 373        unsigned int n;
 374
 375        /* This allows root to remove symlinks */
 376        lock_kernel();
 377        if (!autofs_oz_mode(sbi) && !capable(CAP_SYS_ADMIN)) {
 378                unlock_kernel();
 379                return -EACCES;
 380        }
 381
 382        ent = autofs_hash_lookup(dh, &dentry->d_name);
 383        if (!ent) {
 384                unlock_kernel();
 385                return -ENOENT;
 386        }
 387
 388        n = ent->ino - AUTOFS_FIRST_SYMLINK;
 389        if (n >= AUTOFS_MAX_SYMLINKS) {
 390                unlock_kernel();
 391                return -EISDIR; /* It's a directory, dummy */
 392        }
 393        if (!test_bit(n,sbi->symlink_bitmap)) {
 394                unlock_kernel();
 395                return -EINVAL; /* Nonexistent symlink?  Shouldn't happen */
 396        }
 397        
 398        dentry->d_time = (unsigned long)(struct autofs_dirhash *)NULL;
 399        autofs_hash_delete(ent);
 400        clear_bit(n,sbi->symlink_bitmap);
 401        kfree(sbi->symlink[n].data);
 402        d_drop(dentry);
 403        
 404        unlock_kernel();
 405        return 0;
 406}
 407
 408static int autofs_root_rmdir(struct inode *dir, struct dentry *dentry)
 409{
 410        struct autofs_sb_info *sbi = autofs_sbi(dir->i_sb);
 411        struct autofs_dirhash *dh = &sbi->dirhash;
 412        struct autofs_dir_ent *ent;
 413
 414        lock_kernel();
 415        if (!autofs_oz_mode(sbi)) {
 416                unlock_kernel();
 417                return -EACCES;
 418        }
 419
 420        ent = autofs_hash_lookup(dh, &dentry->d_name);
 421        if (!ent) {
 422                unlock_kernel();
 423                return -ENOENT;
 424        }
 425
 426        if ((unsigned int)ent->ino < AUTOFS_FIRST_DIR_INO) {
 427                unlock_kernel();
 428                return -ENOTDIR; /* Not a directory */
 429        }
 430
 431        if (ent->dentry != dentry) {
 432                printk("autofs_rmdir: odentry != dentry for entry %s\n", dentry->d_name.name);
 433        }
 434
 435        dentry->d_time = (unsigned long)(struct autofs_dir_ent *)NULL;
 436        autofs_hash_delete(ent);
 437        drop_nlink(dir);
 438        d_drop(dentry);
 439        unlock_kernel();
 440
 441        return 0;
 442}
 443
 444static int autofs_root_mkdir(struct inode *dir, struct dentry *dentry, int mode)
 445{
 446        struct autofs_sb_info *sbi = autofs_sbi(dir->i_sb);
 447        struct autofs_dirhash *dh = &sbi->dirhash;
 448        struct autofs_dir_ent *ent;
 449        struct inode *inode;
 450        ino_t ino;
 451
 452        lock_kernel();
 453        if (!autofs_oz_mode(sbi)) {
 454                unlock_kernel();
 455                return -EACCES;
 456        }
 457
 458        ent = autofs_hash_lookup(dh, &dentry->d_name);
 459        if (ent) {
 460                unlock_kernel();
 461                return -EEXIST;
 462        }
 463
 464        if (sbi->next_dir_ino < AUTOFS_FIRST_DIR_INO) {
 465                printk("autofs: Out of inode numbers -- what the heck did you do??\n");
 466                unlock_kernel();
 467                return -ENOSPC;
 468        }
 469        ino = sbi->next_dir_ino++;
 470
 471        ent = kmalloc(sizeof(struct autofs_dir_ent), GFP_KERNEL);
 472        if (!ent) {
 473                unlock_kernel();
 474                return -ENOSPC;
 475        }
 476
 477        ent->name = kmalloc(dentry->d_name.len+1, GFP_KERNEL);
 478        if (!ent->name) {
 479                kfree(ent);
 480                unlock_kernel();
 481                return -ENOSPC;
 482        }
 483
 484        ent->hash = dentry->d_name.hash;
 485        memcpy(ent->name, dentry->d_name.name, 1+(ent->len = dentry->d_name.len));
 486        ent->ino = ino;
 487        ent->dentry = dentry;
 488        autofs_hash_insert(dh,ent);
 489
 490        inc_nlink(dir);
 491
 492        inode = autofs_iget(dir->i_sb, ino);
 493        if (IS_ERR(inode)) {
 494                drop_nlink(dir);
 495                return PTR_ERR(inode);
 496        }
 497
 498        d_instantiate(dentry, inode);
 499        unlock_kernel();
 500
 501        return 0;
 502}
 503
 504/* Get/set timeout ioctl() operation */
 505#ifdef CONFIG_COMPAT
 506static inline int autofs_compat_get_set_timeout(struct autofs_sb_info *sbi,
 507                                         unsigned int __user *p)
 508{
 509        unsigned long ntimeout;
 510
 511        if (get_user(ntimeout, p) ||
 512            put_user(sbi->exp_timeout / HZ, p))
 513                return -EFAULT;
 514
 515        if (ntimeout > UINT_MAX/HZ)
 516                sbi->exp_timeout = 0;
 517        else
 518                sbi->exp_timeout = ntimeout * HZ;
 519
 520        return 0;
 521}
 522#endif
 523
 524static inline int autofs_get_set_timeout(struct autofs_sb_info *sbi,
 525                                         unsigned long __user *p)
 526{
 527        unsigned long ntimeout;
 528
 529        if (get_user(ntimeout, p) ||
 530            put_user(sbi->exp_timeout / HZ, p))
 531                return -EFAULT;
 532
 533        if (ntimeout > ULONG_MAX/HZ)
 534                sbi->exp_timeout = 0;
 535        else
 536                sbi->exp_timeout = ntimeout * HZ;
 537
 538        return 0;
 539}
 540
 541/* Return protocol version */
 542static inline int autofs_get_protover(int __user *p)
 543{
 544        return put_user(AUTOFS_PROTO_VERSION, p);
 545}
 546
 547/* Perform an expiry operation */
 548static inline int autofs_expire_run(struct super_block *sb,
 549                                    struct autofs_sb_info *sbi,
 550                                    struct vfsmount *mnt,
 551                                    struct autofs_packet_expire __user *pkt_p)
 552{
 553        struct autofs_dir_ent *ent;
 554        struct autofs_packet_expire pkt;
 555
 556        memset(&pkt,0,sizeof pkt);
 557
 558        pkt.hdr.proto_version = AUTOFS_PROTO_VERSION;
 559        pkt.hdr.type = autofs_ptype_expire;
 560
 561        if (!sbi->exp_timeout || !(ent = autofs_expire(sb,sbi,mnt)))
 562                return -EAGAIN;
 563
 564        pkt.len = ent->len;
 565        memcpy(pkt.name, ent->name, pkt.len);
 566        pkt.name[pkt.len] = '\0';
 567
 568        if (copy_to_user(pkt_p, &pkt, sizeof(struct autofs_packet_expire)))
 569                return -EFAULT;
 570
 571        return 0;
 572}
 573
 574/*
 575 * ioctl()'s on the root directory is the chief method for the daemon to
 576 * generate kernel reactions
 577 */
 578static int autofs_do_root_ioctl(struct inode *inode, struct file *filp,
 579                             unsigned int cmd, unsigned long arg)
 580{
 581        struct autofs_sb_info *sbi = autofs_sbi(inode->i_sb);
 582        void __user *argp = (void __user *)arg;
 583
 584        DPRINTK(("autofs_ioctl: cmd = 0x%08x, arg = 0x%08lx, sbi = %p, pgrp = %u\n",cmd,arg,sbi,task_pgrp_nr(current)));
 585
 586        if (_IOC_TYPE(cmd) != _IOC_TYPE(AUTOFS_IOC_FIRST) ||
 587             _IOC_NR(cmd) - _IOC_NR(AUTOFS_IOC_FIRST) >= AUTOFS_IOC_COUNT)
 588                return -ENOTTY;
 589        
 590        if (!autofs_oz_mode(sbi) && !capable(CAP_SYS_ADMIN))
 591                return -EPERM;
 592        
 593        switch(cmd) {
 594        case AUTOFS_IOC_READY:  /* Wait queue: go ahead and retry */
 595                return autofs_wait_release(sbi,(autofs_wqt_t)arg,0);
 596        case AUTOFS_IOC_FAIL:   /* Wait queue: fail with ENOENT */
 597                return autofs_wait_release(sbi,(autofs_wqt_t)arg,-ENOENT);
 598        case AUTOFS_IOC_CATATONIC: /* Enter catatonic mode (daemon shutdown) */
 599                autofs_catatonic_mode(sbi);
 600                return 0;
 601        case AUTOFS_IOC_PROTOVER: /* Get protocol version */
 602                return autofs_get_protover(argp);
 603#ifdef CONFIG_COMPAT
 604        case AUTOFS_IOC_SETTIMEOUT32:
 605                return autofs_compat_get_set_timeout(sbi, argp);
 606#endif
 607        case AUTOFS_IOC_SETTIMEOUT:
 608                return autofs_get_set_timeout(sbi, argp);
 609        case AUTOFS_IOC_EXPIRE:
 610                return autofs_expire_run(inode->i_sb, sbi, filp->f_path.mnt,
 611                                         argp);
 612        default:
 613                return -ENOSYS;
 614        }
 615
 616}
 617
 618static long autofs_root_ioctl(struct file *filp,
 619                             unsigned int cmd, unsigned long arg)
 620{
 621        int ret;
 622
 623        lock_kernel();
 624        ret = autofs_do_root_ioctl(filp->f_path.dentry->d_inode,
 625                                   filp, cmd, arg);
 626        unlock_kernel();
 627
 628        return ret;
 629}
 630
 631#ifdef CONFIG_COMPAT
 632static long autofs_root_compat_ioctl(struct file *filp,
 633                             unsigned int cmd, unsigned long arg)
 634{
 635        struct inode *inode = filp->f_path.dentry->d_inode;
 636        int ret;
 637
 638        lock_kernel();
 639        if (cmd == AUTOFS_IOC_READY || cmd == AUTOFS_IOC_FAIL)
 640                ret = autofs_do_root_ioctl(inode, filp, cmd, arg);
 641        else
 642                ret = autofs_do_root_ioctl(inode, filp, cmd,
 643                        (unsigned long)compat_ptr(arg));
 644        unlock_kernel();
 645
 646        return ret;
 647}
 648#endif
 649