lustre/smfs/dir.c

   1 /* -*- mode: c; c-basic-offset: 8; indent-tabs-mode: nil; -*-
   2  * vim:expandtab:shiftwidth=8:tabstop=8:
   3  *
   4  *  Copyright (C) 2004 Cluster File Systems, Inc.
   5  *
   6  *   This file is part of Lustre, http://www.lustre.org.
   7  *
   8  *   Lustre is free software; you can redistribute it and/or
   9  *   modify it under the terms of version 2 of the GNU General Public
  10  *   License as published by the Free Software Foundation.
  11  *
  12  *   Lustre is distributed in the hope that it will be useful,
  13  *   but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  *   GNU General Public License for more details.
  16  *
  17  *   You should have received a copy of the GNU General Public License
  18  *   along with Lustre; if not, write to the Free Software
  19  *   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  20  *
  21  */
  22
  23 #define DEBUG_SUBSYSTEM S_SM
  24
  25 #include <linux/module.h>
  26 #include <linux/kernel.h>
  27 #include <linux/string.h>
  28 #include <linux/slab.h>
  29 #include <linux/stat.h>
  30 #include <linux/unistd.h>
  31 #include <linux/smp_lock.h>
  32 #include <linux/obd_class.h>
  33 #include <linux/obd_support.h>
  34 #include <linux/lustre_lib.h>
  35 #include <linux/lustre_idl.h>
  36 #include <linux/lustre_fsfilt.h>
  37 #include <linux/lustre_smfs.h>
  38 #include <linux/lustre_snap.h>
  39
  40 #include "smfs_internal.h"
  41
  42 #define NAME_ALLOC_LEN(len)     ((len+16) & ~15)
  43
  44 #if (LINUX_VERSION_CODE < KERNEL_VERSION(2,5,0))
  45 static int smfs_create(struct inode *dir, struct dentry *dentry,
  46                        int mode)
  47 #else
  48 static int smfs_create(struct inode *dir, struct dentry *dentry,
  49                        int mode, struct nameidata *nd)
  50 #endif
  51 {
  52         struct inode  *inode = NULL;
  53         struct inode  *cache_dir = NULL;
  54         struct dentry *cache_dentry = NULL;
  55         struct dentry *cache_parent = NULL;
  56         void *handle = NULL;
  57         struct hook_msg msg = {
  58                 .dentry = dentry,
  59         };
  60         int rc = 0;
  61
  62         ENTRY;
  63
  64         cache_dir = I2CI(dir);
  65         LASSERT(cache_dir);
  66         LASSERT(cache_dir->i_op->create);
  67
  68         //lock_kernel();
  69         cache_parent = pre_smfs_dentry(NULL, cache_dir, dentry);
  70         cache_dentry = pre_smfs_dentry(cache_parent, NULL, dentry);
  71         if (!cache_dentry || !cache_parent) {
  72                 rc = -ENOMEM;
  73                 goto exit;
  74         }
  75
  76         handle = smfs_trans_start(dir, FSFILT_OP_CREATE, NULL);
  77         if (IS_ERR(handle)) {
  78                 rc = -ENOSPC;
  79                 goto exit;
  80         }
  81
  82         SMFS_PRE_HOOK(dir, HOOK_CREATE, &msg);
  83
  84         pre_smfs_inode(dir, cache_dir);
  85
  86 #if (LINUX_VERSION_CODE < KERNEL_VERSION(2,5,0))
  87         rc = cache_dir->i_op->create(cache_dir, cache_dentry, mode);
  88 #else
  89         rc = cache_dir->i_op->create(cache_dir, cache_dentry, mode, nd);
  90 #endif
  91         if (!rc) {
  92                 inode = smfs_get_inode(dir->i_sb, cache_dentry->d_inode->i_ino, dir, 0);
  93                 if (inode)
  94                         d_instantiate(dentry, inode);
  95                 else
  96                         rc = -ENOENT;
  97         }
  98
  99         SMFS_POST_HOOK(dir, HOOK_CREATE, &msg, rc);
 100
 101         post_smfs_inode(dir, cache_dir);
 102         smfs_trans_commit(dir, handle, 0);
 103
 104 exit:
 105         //unlock_kernel();
 106         post_smfs_dentry(cache_dentry);
 107         post_smfs_dentry(cache_parent);
 108         RETURN(rc);
 109 }
 110
 111 #if (LINUX_VERSION_CODE < KERNEL_VERSION(2,5,0))
 112 static struct dentry *smfs_lookup(struct inode *dir, struct dentry *dentry)
 113 #else
 114 static struct dentry *smfs_lookup(struct inode *dir, struct dentry *dentry,
 115                                   struct nameidata *nd)
 116 #endif
 117 {
 118         struct inode *cache_dir;
 119         struct inode *inode = NULL;
 120         struct inode * cache_inode = NULL;
 121         struct dentry *cache_dentry = NULL;
 122         struct dentry *cache_parent = NULL;
 123         struct dentry *rdentry = NULL;
 124         int rc = 0;
 125         struct hook_msg msg = {
 126                 .dentry = dentry,
 127         };
 128
 129         ENTRY;
 130
 131         cache_dir = I2CI(dir);
 132         if (!cache_dir)
 133                 RETURN(ERR_PTR(-ENOENT));
 134
 135         LASSERT(cache_dir->i_op->lookup);
 136
 137         /* preparing artificial backing fs dentries. */
 138         cache_parent = pre_smfs_dentry(NULL, cache_dir, dentry->d_parent);
 139         cache_dentry = pre_smfs_dentry(cache_parent, NULL, dentry);
 140         if (!cache_dentry || !cache_parent)
 141                 RETURN(ERR_PTR(-ENOMEM));
 142
 143         SMFS_PRE_HOOK(dir, HOOK_LOOKUP, &msg);
 144
 145         /* perform lookup in backing fs. */
 146 #if (LINUX_VERSION_CODE < KERNEL_VERSION(2,5,0))
 147         rdentry = cache_dir->i_op->lookup(cache_dir, cache_dentry);
 148 #else
 149         rdentry = cache_dir->i_op->lookup(cache_dir, cache_dentry, nd);
 150 #endif
 151         if (rdentry) {
 152                 if (IS_ERR(rdentry))
 153                         rc = PTR_ERR(rdentry);
 154                 else {
 155                         cache_inode = rdentry->d_inode;
 156                         dput(rdentry);
 157                 }
 158         } else {
 159                 cache_inode = cache_dentry->d_inode;
 160         }
 161
 162         if (cache_inode) {
 163                 inode = smfs_get_inode(dir->i_sb, cache_inode->i_ino, dir,0);
 164                 if (!inode)
 165                         rc = -ENOENT;
 166         }
 167
 168         if (!rc)
 169                 d_add(dentry, inode);
 170
 171         SMFS_POST_HOOK(dir, HOOK_LOOKUP, &msg, rc);
 172 exit:
 173         post_smfs_dentry(cache_dentry);
 174         post_smfs_dentry(cache_parent);
 175         RETURN(ERR_PTR(rc));
 176 }
 177
 178 static int smfs_link(struct dentry *old_dentry,
 179                      struct inode *dir, struct dentry *dentry)
 180 {
 181         struct inode *cache_old_inode = NULL;
 182         struct inode *cache_dir = NULL;
 183         struct inode *old_inode = NULL;
 184         struct dentry *cache_dentry = NULL;
 185         struct dentry *cache_old_dentry = NULL;
 186         struct dentry *cache_parent = NULL;
 187         void *handle = NULL;
 188         int rc = 0;
 189         struct hook_msg msg = {
 190                 .dentry = old_dentry,
 191         };
 192
 193         ENTRY;
 194
 195         cache_dir = I2CI(dir);
 196         if (!cache_dir)
 197                 RETURN(-ENOENT);
 198
 199         old_inode = old_dentry->d_inode;
 200         cache_old_inode = I2CI(old_inode);
 201         if (!cache_old_inode)
 202                 RETURN(-ENOENT);
 203
 204         cache_parent = pre_smfs_dentry(NULL, cache_dir, dentry);
 205         cache_dentry = pre_smfs_dentry(cache_parent, NULL, dentry);
 206         cache_old_dentry = pre_smfs_dentry(NULL, cache_old_inode, old_dentry);
 207         if (!cache_old_dentry || !cache_dentry || !cache_parent) {
 208                 rc = -ENOMEM;
 209                 goto exit;
 210         }
 211
 212         handle = smfs_trans_start(dir, FSFILT_OP_LINK, NULL);
 213         if (IS_ERR(handle)) {
 214                  rc = -ENOSPC;
 215                  goto exit;
 216         }
 217
 218         pre_smfs_inode(dir, cache_dir);
 219         pre_smfs_inode(old_inode, cache_old_inode);
 220
 221         //lock_kernel();
 222         SMFS_PRE_HOOK(dir, HOOK_LINK, &msg);
 223
 224         rc = cache_dir->i_op->link(cache_old_dentry, cache_dir, cache_dentry);
 225         if (!rc) {
 226                 atomic_inc(&old_inode->i_count);
 227                 d_instantiate(dentry, old_inode);
 228         }
 229
 230         SMFS_POST_HOOK(dir, HOOK_LINK, &msg, rc);
 231
 232         post_smfs_inode(old_inode, cache_old_inode);
 233         post_smfs_inode(dir, cache_dir);
 234
 235         smfs_trans_commit(dir, handle, 0);
 236
 237 exit:
 238         //unlock_kernel();
 239         post_smfs_dentry(cache_dentry);
 240         post_smfs_dentry(cache_parent);
 241         post_smfs_dentry(cache_old_dentry);
 242
 243         RETURN(rc);
 244 }
 245
 246 static int smfs_unlink(struct inode * dir, struct dentry *dentry)
 247 {
 248         struct inode *cache_dir = I2CI(dir);
 249         struct inode *cache_inode = I2CI(dentry->d_inode);
 250         struct dentry *cache_dentry;
 251         struct dentry *cache_parent;
 252         void   *handle = NULL;
 253         int    rc = 0;
 254         //int    mode = 0;
 255         struct hook_unlink_msg msg = {
 256                 .dentry = dentry,
 257                 .mode = 0
 258         };
 259
 260         ENTRY;
 261
 262         if (!cache_dir || !cache_inode || !cache_dir->i_op->unlink)
 263                 RETURN(-ENOENT);
 264
 265         cache_parent = pre_smfs_dentry(NULL, cache_dir, dentry);
 266         cache_dentry = pre_smfs_dentry(cache_parent, cache_inode, dentry);
 267         if (!cache_dentry || !cache_parent) {
 268                 rc = -ENOMEM;
 269                 goto exit;
 270         }
 271
 272         //lock_kernel();
 273         handle = smfs_trans_start(dir, FSFILT_OP_UNLINK, NULL);
 274         if (IS_ERR(handle)) {
 275                 rc = -ENOSPC;
 276                 goto exit;
 277         }
 278
 279         pre_smfs_inode(dir, cache_dir);
 280         pre_smfs_inode(dentry->d_inode, cache_inode);
 281
 282         SMFS_PRE_HOOK(dir, HOOK_UNLINK, &msg);
 283
 284         rc = cache_dir->i_op->unlink(cache_dir, cache_dentry);
 285
 286         SMFS_POST_HOOK(dir, HOOK_UNLINK, &msg, rc);
 287
 288         post_smfs_inode(dentry->d_inode, cache_dentry->d_inode);
 289         post_smfs_inode(dir, cache_dir);
 290         //unlock_kernel();
 291
 292         smfs_trans_commit(dir, handle, 0);
 293 exit:
 294         post_smfs_dentry(cache_dentry);
 295         post_smfs_dentry(cache_parent);
 296         RETURN(rc);
 297 }
 298
 299 static int smfs_symlink(struct inode *dir, struct dentry *dentry,
 300                         const char *symname)
 301 {
 302         struct inode *cache_dir = I2CI(dir);
 303         struct inode *inode = NULL;
 304         struct dentry *cache_dentry;
 305         struct dentry *cache_parent;
 306         void   *handle = NULL;
 307         int    rc = 0;
 308         struct hook_symlink_msg msg = {
 309                 .dentry = dentry,
 310                 .tgt_len = strlen(symname) + 1,
 311                 .symname = (char*)symname
 312         };
 313
 314         ENTRY;
 315
 316         if (!cache_dir || !cache_dir->i_op->symlink)
 317                 RETURN(-ENOENT);
 318
 319         cache_parent = pre_smfs_dentry(NULL, cache_dir, dentry);
 320         cache_dentry = pre_smfs_dentry(cache_parent, NULL, dentry);
 321         if (!cache_parent || !cache_dentry) {
 322                 rc = -ENOMEM;
 323                 goto exit;
 324         }
 325
 326         handle = smfs_trans_start(dir, FSFILT_OP_SYMLINK, NULL);
 327         if (IS_ERR(handle)) {
 328                 rc = -ENOSPC;
 329                 goto exit;
 330         }
 331
 332         //lock_kernel();
 333         pre_smfs_inode(dir, cache_dir);
 334
 335         SMFS_PRE_HOOK(dir, HOOK_SYMLINK, &msg);
 336
 337         rc = cache_dir->i_op->symlink(cache_dir, cache_dentry, symname);
 338         if (!rc) {
 339                 inode = smfs_get_inode(dir->i_sb, cache_dentry->d_inode->i_ino,
 340                                        dir, 0);
 341                 if (inode)
 342                         d_instantiate(dentry, inode);
 343                 else
 344                         rc = -ENOENT;
 345         }
 346
 347         SMFS_POST_HOOK(dir, HOOK_SYMLINK, &msg, rc);
 348
 349         post_smfs_inode(dir, cache_dir);
 350         smfs_trans_commit(dir, handle, 0);
 351
 352 exit:
 353         //unlock_kernel();
 354         post_smfs_dentry(cache_dentry);
 355         post_smfs_dentry(cache_parent);
 356         RETURN(rc);
 357 }
 358
 359 static int smfs_mkdir(struct inode *dir, struct dentry *dentry,
 360                       int mode)
 361 {
 362         struct inode *cache_dir = I2CI(dir);
 363         struct inode *inode = NULL;
 364         struct dentry *cache_dentry;
 365         struct dentry *cache_parent;
 366         void   *handle = NULL;
 367         int    rc = 0;
 368         struct hook_msg msg = {
 369                 .dentry = dentry,
 370         };
 371
 372         ENTRY;
 373
 374         if (!cache_dir)
 375                 RETURN(-ENOENT);
 376
 377         cache_parent = pre_smfs_dentry(NULL, cache_dir, dentry);
 378         cache_dentry = pre_smfs_dentry(cache_parent, NULL, dentry);
 379
 380         if (!cache_parent || !cache_dentry) {
 381                 rc = -ENOMEM;
 382                 goto exit;
 383         }
 384
 385         handle = smfs_trans_start(dir, FSFILT_OP_MKDIR, NULL);
 386         if (IS_ERR(handle)) {
 387                 rc = -ENOSPC;
 388                 goto exit;
 389         }
 390
 391         pre_smfs_inode(dir, cache_dir);
 392         SMFS_PRE_HOOK(dir, HOOK_MKDIR, &msg);
 393
 394         rc = cache_dir->i_op->mkdir(cache_dir, cache_dentry, mode);
 395         if (!rc) {
 396                 inode = smfs_get_inode(dir->i_sb, cache_dentry->d_inode->i_ino,
 397                                        dir, 0);
 398                 if (inode)
 399                         d_instantiate(dentry, inode);
 400                 else
 401                         rc = -ENOENT;
 402         }
 403
 404         SMFS_POST_HOOK(dir, HOOK_MKDIR, &msg, rc);
 405         post_smfs_inode(dir, cache_dir);
 406         smfs_trans_commit(dir, handle, 0);
 407
 408 exit:
 409         post_smfs_dentry(cache_dentry);
 410         post_smfs_dentry(cache_parent);
 411         RETURN(rc);
 412 }
 413
 414 static int smfs_rmdir(struct inode *dir, struct dentry *dentry)
 415 {
 416         struct inode *cache_dir = I2CI(dir);
 417         struct inode *cache_inode = I2CI(dentry->d_inode);
 418         struct dentry *cache_dentry = NULL;
 419         struct dentry *cache_parent = NULL;
 420         void *handle = NULL;
 421         int    rc = 0;
 422         struct hook_unlink_msg msg = {
 423                 .dentry = dentry,
 424                 .mode = S_IFDIR
 425         };
 426
 427         ENTRY;
 428
 429         if (!cache_dir || !cache_dir->i_op->rmdir)
 430                 RETURN(-ENOENT);
 431
 432         cache_parent = pre_smfs_dentry(NULL, cache_dir, dentry);
 433         cache_dentry = pre_smfs_dentry(cache_parent, cache_inode, dentry);
 434         if (!cache_parent || !cache_dentry) {
 435                 rc = -ENOMEM;
 436                 goto exit;
 437         }
 438
 439         handle = smfs_trans_start(dir, FSFILT_OP_RMDIR, NULL);
 440         if (IS_ERR(handle) ) {
 441                 rc = -ENOSPC;
 442                 goto exit;
 443         }
 444
 445         pre_smfs_inode(dir, cache_dir);
 446         pre_smfs_inode(dentry->d_inode, cache_dentry->d_inode);
 447
 448         SMFS_PRE_HOOK(dir, HOOK_RMDIR, &msg);
 449
 450         rc = cache_dir->i_op->rmdir(cache_dir, cache_dentry);
 451
 452         SMFS_POST_HOOK(dir, HOOK_RMDIR, &msg, rc);
 453
 454         post_smfs_inode(dir, cache_dir);
 455         post_smfs_inode(dentry->d_inode, cache_dentry->d_inode);
 456
 457         smfs_trans_commit(dir, handle, 0);
 458
 459 exit:
 460         post_smfs_dentry(cache_dentry);
 461         post_smfs_dentry(cache_parent);
 462         RETURN(rc);
 463 }
 464
 465 #if (LINUX_VERSION_CODE < KERNEL_VERSION(2,5,0))
 466 static int smfs_mknod(struct inode *dir, struct dentry *dentry,
 467                       int mode, int rdev)
 468 #else
 469 static int smfs_mknod(struct inode *dir, struct dentry *dentry,
 470                       int mode, dev_t rdev)
 471 #endif
 472 {
 473         struct inode *cache_dir = I2CI(dir);
 474         struct inode *inode = NULL;
 475         struct dentry *cache_dentry = NULL;
 476         struct dentry *cache_parent = NULL;
 477         void *handle = NULL;
 478         int rc = 0;
 479         struct hook_msg msg = {
 480                 .dentry = dentry,
 481         };
 482
 483         ENTRY;
 484
 485         if (!cache_dir || !cache_dir->i_op->mknod)
 486                 RETURN(-ENOENT);
 487
 488         cache_parent = pre_smfs_dentry(NULL, cache_dir, dentry->d_parent);
 489         cache_dentry = pre_smfs_dentry(cache_parent, NULL, dentry);
 490         if (!cache_parent || !cache_dentry) {
 491                 rc = -ENOMEM;
 492                 goto exit;
 493         }
 494
 495         handle = smfs_trans_start(dir, FSFILT_OP_MKNOD, NULL);
 496         if (IS_ERR(handle)) {
 497                 rc = -ENOSPC;
 498                 goto exit;
 499         }
 500
 501         pre_smfs_inode(dir, cache_dir);
 502         pre_smfs_inode(dentry->d_inode, cache_dentry->d_inode);
 503
 504         SMFS_PRE_HOOK(dir, HOOK_MKNOD, &msg);
 505
 506         rc = cache_dir->i_op->mknod(cache_dir, cache_dentry, mode, rdev);
 507         if (!rc) {
 508                 inode = smfs_get_inode(dir->i_sb, cache_dentry->d_inode->i_ino,
 509                                        dir, 0);
 510                 if (inode)
 511                         d_instantiate(dentry, inode);
 512                 else
 513                         rc = -ENOENT;
 514         }
 515
 516         SMFS_POST_HOOK(dir, HOOK_MKNOD, &msg, rc);
 517
 518         post_smfs_inode(dir, cache_dir);
 519         post_smfs_inode(dentry->d_inode, cache_dentry->d_inode);
 520         smfs_trans_commit(dir, handle, 0);
 521
 522 exit:
 523         post_smfs_dentry(cache_dentry);
 524         post_smfs_dentry(cache_parent);
 525         RETURN(rc);
 526 }
 527
 528 static int smfs_rename(struct inode *old_dir, struct dentry *old_dentry,
 529                        struct inode *new_dir,struct dentry *new_dentry)
 530 {
 531         struct inode *cache_old_dir = I2CI(old_dir);
 532         struct inode *cache_new_dir = I2CI(new_dir);
 533         struct inode *cache_old_inode = I2CI(old_dentry->d_inode);
 534         struct inode *cache_new_inode = NULL;
 535         struct dentry *cache_old_dentry = NULL;
 536         struct dentry *cache_new_dentry = NULL;
 537         struct dentry *cache_new_parent = NULL;
 538         struct dentry *cache_old_parent = NULL;
 539         void *handle = NULL;
 540         int    rc = 0;
 541         struct hook_rename_msg msg = {
 542                 .dentry = old_dentry,
 543                 .new_dir = new_dir,
 544                 .new_dentry = new_dentry
 545         };
 546
 547         ENTRY;
 548
 549         if (!cache_old_dir || !cache_new_dir || !cache_old_inode)
 550                 RETURN(-ENOENT);
 551
 552         if (new_dentry->d_inode) {
 553                 cache_new_inode = I2CI(new_dentry->d_inode);
 554                 if (!cache_new_inode)
 555                         RETURN(-ENOENT);
 556         }
 557
 558         cache_old_parent = pre_smfs_dentry(NULL, cache_old_dir, old_dentry);
 559         cache_old_dentry = pre_smfs_dentry(cache_old_parent, cache_old_inode,
 560                                            old_dentry);
 561         if (!cache_old_parent || !cache_old_dentry) {
 562                 rc = -ENOMEM;
 563                 goto exit;
 564         }
 565
 566         cache_new_parent = pre_smfs_dentry(NULL, cache_new_dir, new_dentry);
 567         cache_new_dentry = pre_smfs_dentry(cache_new_parent, cache_new_inode,
 568                                            new_dentry);
 569         if (!cache_new_parent || !cache_new_dentry) {
 570                 rc = -ENOMEM;
 571                 goto exit;
 572         }
 573
 574         handle = smfs_trans_start(old_dir, FSFILT_OP_RENAME, NULL);
 575         if (IS_ERR(handle)) {
 576                 rc = -ENOSPC;
 577                 goto exit;
 578         }
 579
 580         pre_smfs_inode(old_dir, cache_old_dir);
 581         pre_smfs_inode(new_dir, cache_new_dir);
 582         if (new_dentry->d_inode)
 583                 pre_smfs_inode(new_dentry->d_inode, cache_new_dentry->d_inode);
 584
 585         SMFS_PRE_HOOK(old_dir, HOOK_RENAME, &msg);
 586
 587         rc = cache_old_dir->i_op->rename(cache_old_dir, cache_old_dentry,
 588                                          cache_new_dir, cache_new_dentry);
 589
 590         SMFS_POST_HOOK(old_dir, HOOK_RENAME, &msg, rc);
 591
 592         post_smfs_inode(old_dir, cache_old_dir);
 593         post_smfs_inode(new_dir, cache_new_dir);
 594         if (new_dentry->d_inode)
 595                 post_smfs_inode(new_dentry->d_inode, cache_new_dentry->d_inode);
 596
 597         smfs_trans_commit(old_dir, handle, 0);
 598
 599 exit:
 600         post_smfs_dentry(cache_old_dentry);
 601         post_smfs_dentry(cache_old_parent);
 602         post_smfs_dentry(cache_new_dentry);
 603         post_smfs_dentry(cache_new_parent);
 604         RETURN(rc);
 605 }
 606
 607 struct inode_operations smfs_dir_iops = {
 608         create:         smfs_create,
 609         lookup:         smfs_lookup,
 610         link:           smfs_link,              /* BKL held */
 611         unlink:         smfs_unlink,            /* BKL held */
 612         symlink:        smfs_symlink,           /* BKL held */
 613         mkdir:          smfs_mkdir,             /* BKL held */
 614         rmdir:          smfs_rmdir,             /* BKL held */
 615         mknod:          smfs_mknod,             /* BKL held */
 616         rename:         smfs_rename,            /* BKL held */
 617         setxattr:       smfs_setxattr,          /* BKL held */
 618         getxattr:       smfs_getxattr,          /* BKL held */
 619         listxattr:      smfs_listxattr,         /* BKL held */
 620         removexattr:    smfs_removexattr,       /* BKL held */
 621 };
 622
 623 static ssize_t smfs_read_dir(struct file *filp, char *buf,
 624                              size_t size, loff_t *ppos)
 625 {
 626         struct dentry *dentry = filp->f_dentry;
 627         struct inode *cache_inode = NULL;
 628         struct smfs_file_info *sfi = NULL;
 629         loff_t tmp_ppos;
 630         loff_t *cache_ppos = NULL;
 631         int    rc = 0;
 632
 633         ENTRY;
 634
 635         cache_inode = I2CI(dentry->d_inode);
 636
 637         if (!cache_inode || !cache_inode->i_fop->read)
 638                 RETURN(-EINVAL);
 639
 640         sfi = F2SMFI(filp);
 641         if (sfi->magic != SMFS_FILE_MAGIC)
 642                 BUG();
 643
 644         if (ppos != &(filp->f_pos))
 645                 cache_ppos = &tmp_ppos;
 646         else
 647                 cache_ppos = &sfi->c_file->f_pos;
 648
 649         *cache_ppos = *ppos;
 650
 651         rc = cache_inode->i_fop->read(sfi->c_file, buf, size, cache_ppos);
 652         if (rc)
 653                 RETURN(rc);
 654
 655         *ppos = *cache_ppos;
 656
 657         duplicate_file(filp, sfi->c_file);
 658
 659         RETURN(rc);
 660 }
 661
 662 static int smfs_readdir(struct file *filp, void *dirent, filldir_t filldir)
 663 {
 664         struct dentry *dentry = filp->f_dentry;
 665         struct inode *cache_inode = NULL;
 666         struct smfs_file_info *sfi = NULL;
 667         int    rc = 0;
 668         struct hook_readdir_msg msg = {
 669                 .dentry = dentry,
 670                 .filp = filp,
 671                 .dirent = dirent,
 672                 .filldir = filldir
 673         };
 674
 675         ENTRY;
 676
 677         cache_inode = I2CI(dentry->d_inode);
 678         if (!cache_inode || !cache_inode->i_fop->readdir)
 679                 RETURN(-EINVAL);
 680
 681         sfi = F2SMFI(filp);
 682         if (sfi->magic != SMFS_FILE_MAGIC) BUG();
 683
 684         SMFS_PRE_HOOK(dentry->d_inode, HOOK_READDIR, &msg);
 685
 686         rc = cache_inode->i_fop->readdir(sfi->c_file, dirent, filldir);
 687
 688         SMFS_POST_HOOK(dentry->d_inode, HOOK_READDIR, &msg, rc);
 689         duplicate_file(filp, sfi->c_file);
 690
 691 exit:
 692         if (rc > 0)
 693                 rc = 0;
 694
 695         RETURN(rc);
 696 }
 697
 698 struct file_operations smfs_dir_fops = {
 699         .read           = smfs_read_dir,
 700         .readdir        = smfs_readdir,       /* BKL held */
 701         .ioctl          = smfs_ioctl,         /* BKL held */
 702         .fsync          = smfs_fsync,         /* BKL held */
 703         .open           = smfs_open,
 704         .release        = smfs_release,
 705 };