lustre/smfs/smfs_cow.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/pagemap.h>
  28 #include <linux/string.h>
  29 #include <linux/slab.h>
  30 #include <linux/stat.h>
  31 #include <linux/unistd.h>
  32 #include <linux/smp_lock.h>
  33 #include <linux/obd_class.h>
  34 #include <linux/obd_support.h>
  35 #include <linux/lustre_lib.h>
  36 #include <linux/lustre_idl.h>
  37 #include <linux/lustre_fsfilt.h>
  38
  39 #include <linux/lustre_smfs.h>
  40 #include <linux/lustre_snap.h>
  41
  42 #include "smfs_internal.h"
  43
  44 #define SNAPTABLE_SIZE(size) (sizeof(struct snap_table) +       \
  45                               size * sizeof(struct snap))
  46
  47 int smfs_cleanup_snap_info(struct snap_info *snap_info);
  48
  49 static int smfs_init_snap_super_info(struct smfs_super_info *smfs_info)
  50 {
  51         struct snap_super_info  *snap_sinfo;
  52         int rc = 0;
  53
  54         ENTRY;
  55
  56         OBD_ALLOC(smfs_info->smsi_snap_info,
  57                   sizeof(struct snap_super_info));
  58
  59         if (!smfs_info->smsi_snap_info)
  60                 GOTO(exit, rc = -ENOMEM);
  61
  62         snap_sinfo = smfs_info->smsi_snap_info;
  63
  64         /*init snap fsfilt operations*/
  65         if (!snap_sinfo->snap_cache_fsfilt) {
  66                 char *snap_cache_ftype = NULL;
  67                 int   tmp = strlen(smfs_info->smsi_cache_ftype) + strlen("_snap");
  68
  69                 OBD_ALLOC(snap_cache_ftype, tmp + 1);
  70                 sprintf(snap_cache_ftype, "%s_snap", smfs_info->smsi_cache_ftype);
  71                 snap_sinfo->snap_cache_fsfilt = fsfilt_get_ops(snap_cache_ftype);
  72                 OBD_FREE(snap_cache_ftype, tmp + 1);
  73                 if (!snap_sinfo->snap_cache_fsfilt) {
  74                         CERROR("Can not get %s fsfilt ops needed by snap\n",
  75                                snap_cache_ftype);
  76                         GOTO(exit, rc = -EINVAL);
  77                 }
  78         }
  79         if (!snap_sinfo->snap_fsfilt) {
  80                 char *snap_ftype = NULL;
  81                 int   tmp = strlen(smfs_info->smsi_ftype) + strlen("_snap");
  82
  83                 OBD_ALLOC(snap_ftype, tmp + 1);
  84                 sprintf(snap_ftype, "%s_snap", smfs_info->smsi_ftype);
  85                 snap_sinfo->snap_fsfilt = fsfilt_get_ops(snap_ftype);
  86                 OBD_FREE(snap_ftype, tmp + 1);
  87                 if (!snap_sinfo->snap_fsfilt) {
  88                         CERROR("Can not get %s fsfilt ops needed by snap\n",
  89                                snap_ftype);
  90                         GOTO(exit, rc = -EINVAL);
  91                 }
  92         }
  93         INIT_LIST_HEAD(&snap_sinfo->snap_list);
  94 exit:
  95         if (rc && smfs_info->smsi_snap_info)
  96                 OBD_FREE(snap_sinfo, sizeof(struct snap_super_info));
  97         RETURN(rc);
  98 }
  99 /*FIXME-wangdi Should remove it when integrated it with lustre*/
 100 static struct dentry *smfs_simple_mkdir(struct dentry *dir, char *name,
 101                                         int mode, int fix)
 102 {
 103         struct dentry *dchild;
 104         int err = 0;
 105
 106         dchild = ll_lookup_one_len(name, dir, strlen(name));
 107         if (IS_ERR(dchild))
 108                 GOTO(out_up, dchild);
 109
 110         if (dchild->d_inode) {
 111                 int old_mode = dchild->d_inode->i_mode;
 112                 if (!S_ISDIR(old_mode))
 113                         GOTO(out_err, err = -ENOTDIR);
 114
 115                 /* Fixup directory permissions if necessary */
 116                 if (fix && (old_mode & S_IALLUGO) != (mode & S_IALLUGO)) {
 117                         CWARN("fixing permissions on %s from %o to %o\n",
 118                               name, old_mode, mode);
 119                         dchild->d_inode->i_mode = (mode & S_IALLUGO) |
 120                                                   (old_mode & ~S_IALLUGO);
 121                         mark_inode_dirty(dchild->d_inode);
 122                 }
 123                 GOTO(out_up, dchild);
 124         }
 125         err = vfs_mkdir(dir->d_inode, dchild, mode);
 126         if (err)
 127                 GOTO(out_err, err);
 128         RETURN(dchild);
 129 out_err:
 130         dput(dchild);
 131         dchild = ERR_PTR(err);
 132 out_up:
 133         return dchild;
 134
 135 }
 136 static struct snap_info *smfs_find_snap_info(struct inode *inode)
 137 {
 138         struct snap_inode_info *snap_iinfo = I2SNAPI(inode);
 139         struct snap_super_info *snap_sinfo = S2SNAPI(inode->i_sb);
 140         struct snap_info *snap_info = NULL, *tmp;
 141
 142         ENTRY;
 143         list_for_each_entry_safe(snap_info, tmp, &snap_sinfo->snap_list,
 144                                  sni_list) {
 145                if (snap_info->sni_root_ino == snap_iinfo->sn_root_ino)
 146                         RETURN(snap_info);
 147         }
 148         RETURN(NULL);
 149 }
 150
 151 #if 0
 152 static int smfs_dotsnap_dir_size(struct inode *inode)
 153 {
 154         struct snap_super_info *snap_sinfo = S2SNAPI(inode->i_sb);
 155         struct fsfilt_operations *snapops = snap_sinfo->snap_cache_fsfilt;
 156         int size = 0, dir_size = 0, blocks, i = 0;
 157         struct snap_table *snap_table = NULL;
 158         struct snap_info *snap_info = NULL;
 159         ENTRY;
 160
 161         snap_info = smfs_find_snap_info(inode);
 162
 163         if (!snap_info) {
 164                 CDEBUG(D_INFO, "can not find snap info for inode %p\n", inode);
 165                 RETURN(0);
 166         }
 167         snap_table = snap_info->sni_table;
 168         for (i = 0; i < snap_table->sntbl_count; i++) {
 169                 char *name = snap_table->sntbl_items[i].sn_name;
 170                 size += snapops->fs_dir_ent_size(name);
 171         }
 172         /*FIXME this is only for ext3 dir format, may need fix for other FS*/
 173         blocks = (size + inode->i_sb->s_blocksize - 1) >>
 174                                 inode->i_sb->s_blocksize_bits;
 175
 176         dir_size = blocks * inode->i_sb->s_blocksize;
 177         RETURN(dir_size);
 178
 179 }
 180 #endif
 181
 182 static int smfs_init_snap_inode_info(struct inode *inode, struct inode *dir, int index)
 183 {
 184         int rc = 0;
 185         ENTRY;
 186
 187         if (!inode)
 188                 RETURN(0);
 189
 190         if (dir) {
 191                 I2SNAPI(inode)->sn_flags = I2SNAPI(dir)->sn_flags;
 192                 I2SNAPI(inode)->sn_gen = I2SNAPI(dir)->sn_gen;
 193                 I2SNAPI(inode)->sn_root_ino = I2SNAPI(dir)->sn_root_ino;
 194                 I2SNAPI(inode)->sn_index = I2SNAPI(inode)->sn_index;
 195         } else {
 196                 I2SNAPI(inode)->sn_flags = 0;
 197                 I2SNAPI(inode)->sn_gen = 0;
 198         }
 199
 200         I2SNAPI(inode)->sn_index = index;
 201
 202         if (smfs_dotsnap_inode(inode)) {
 203                 struct snap_info *snap_info;
 204
 205                 snap_info = smfs_find_snap_info(inode);
 206                 if (!snap_info) {
 207                         RETURN(-EIO);
 208                 }
 209                 /*init dot_snap inode info*/
 210 //              inode->i_size = (loff_t)smfs_dotsnap_dir_size(inode);
 211                 inode->i_size = snap_info->sni_table->sntbl_count;
 212                 inode->i_nlink = snap_info->sni_table->sntbl_count + 2;
 213                 inode->i_uid = 0;
 214                 inode->i_gid = 0;
 215         } else if (SMFS_DO_COW(S2SMI(inode->i_sb)) &&
 216                    (I2SMI(inode)->smi_flags & SM_DO_COW) &&
 217                    smfs_primary_inode(inode)) {
 218                 struct snap_inode_info *sni_info = I2SNAPI(inode);
 219                 struct fsfilt_operations *sops = I2SNAPCOPS(inode);
 220                 int vallen = 0;
 221
 222                 vallen = sizeof(sni_info->sn_gen);
 223
 224                 rc = sops->fs_get_snap_info(I2CI(inode), SNAP_GENERATION,
 225                                             strlen(SNAP_GENERATION),
 226                                             &sni_info->sn_gen, &vallen);
 227         }
 228         RETURN(rc);
 229 }
 230
 231 #define COWED_NAME_LEN       (7 + 8 + 1)
 232 static int smfs_init_cowed_dir(struct snap_info *snap_info, struct inode* inode)
 233 {
 234         struct dentry    *dentry = NULL;
 235         char   name[COWED_NAME_LEN];
 236         int    rc = 0;
 237         ENTRY;
 238
 239         sprintf(name, ".cowed_%08x", (__u32)inode->i_ino);
 240         /*FIXME-WANGDI: will use simple_mkdir, when integrating snap to lustre*/
 241         dentry = smfs_simple_mkdir(inode->i_sb->s_root, name, 0777, 1);
 242         if (IS_ERR(dentry)) {
 243                 rc = PTR_ERR(dentry);
 244                 CERROR("create cowed directory: rc = %d\n", rc);
 245                 RETURN(rc);
 246         }
 247         snap_info->sni_cowed_dentry = dentry;
 248         /*cleanup cowed inode attr for cowed dir*/
 249         SMFS_CLEAN_INODE_COWED(dentry->d_inode);
 250         RETURN(rc);
 251 }
 252
 253 static int smfs_init_dotinfo(struct snap_info *snap_info)
 254 {
 255         struct snap_dot_info *dot_info = NULL;
 256         int rc = 0;
 257         ENTRY;
 258
 259         if (snap_info->sni_dot_info)
 260                 RETURN(-EEXIST);
 261
 262         OBD_ALLOC(snap_info->sni_dot_info, sizeof(struct snap_dot_info));
 263
 264         if (!snap_info->sni_dot_info)
 265                 RETURN(-ENOMEM);
 266
 267         dot_info = snap_info->sni_dot_info;
 268
 269         OBD_ALLOC(dot_info->dot_name,  strlen(DOT_SNAP_NAME) + 1);
 270
 271         if (!dot_info->dot_name) {
 272                 OBD_FREE(snap_info->sni_dot_info, sizeof(struct snap_dot_info));
 273                 RETURN(-ENOMEM);
 274         }
 275         memcpy(dot_info->dot_name, DOT_SNAP_NAME, strlen(DOT_SNAP_NAME));
 276
 277         dot_info->dot_name_len = strlen(DOT_SNAP_NAME);
 278         dot_info->dot_snap_enable = 1;
 279
 280         RETURN(rc);
 281 }
 282
 283 static int smfs_init_snap_info(struct smfs_super_info *smb,
 284                                struct snap_info *snap_info, struct inode *inode)
 285 {
 286         struct snap_table        *snap_table = NULL;
 287         struct fsfilt_operations *snapcops;
 288         int                      rc = 0, size, table_size, vallen, i;
 289
 290         ENTRY;
 291
 292         snapcops = smb->smsi_snap_info->snap_cache_fsfilt;
 293         /*Initialized table */
 294         /*get the maxsize of snaptable*/
 295         vallen = sizeof(int);
 296         rc = snapcops->fs_get_snap_info(I2CI(inode), MAX_SNAPTABLE_COUNT,
 297                                        strlen(MAX_SNAPTABLE_COUNT), &size,
 298                                        &vallen);
 299         if (size == 0) {
 300                 CERROR("the Max snaptable count should not be zero\n");
 301                 GOTO(exit, rc);
 302         }
 303         table_size = SNAPTABLE_SIZE(size);
 304
 305         OBD_ALLOC(snap_info->sni_table, table_size);
 306
 307         if (!snap_info->sni_table) {
 308                 CERROR("No MEM\n");
 309                 RETURN(-ENOMEM);
 310         }
 311         snap_table = snap_info->sni_table;
 312
 313         snap_table->sntbl_magic = cpu_to_le32((__u32)SNAPTABLE_MAGIC);
 314         snap_table->sntbl_max_count = size;
 315         /*init sn_index to -1*/
 316         for (i = 0; i < snap_table->sntbl_max_count; i++)
 317                 snap_table->sntbl_items[i].sn_index = -1;
 318         /*get snaptable info*/
 319         rc = snapcops->fs_get_snap_info(I2CI(inode), SNAPTABLE_INFO,
 320                                         strlen(SNAPTABLE_INFO),
 321                                         snap_table, &table_size);
 322         if (rc < 0) {
 323                 if (rc == -ENODATA) {
 324                         snap_table->sntbl_count = 0;
 325                         rc = 0;
 326                 } else {
 327                         CERROR("Can not retrive the snaptable from this filesystem\n");
 328                         GOTO(exit, rc);
 329                 }
 330         } else {
 331                 if (le32_to_cpu(snap_table->sntbl_magic) != SNAPTABLE_MAGIC) {
 332                         CERROR("On disk snaptable is not right \n");
 333                         GOTO(exit, rc = -EIO);
 334                 }
 335         }
 336         init_MUTEX(&snap_info->sni_sema);
 337         snap_info->sni_root_ino = inode->i_ino;
 338         rc = smfs_init_cowed_dir(snap_info, inode);
 339         if (rc) {
 340                 CERROR("Init cowed dir error rc=%d\n", rc);
 341                 GOTO(exit, rc);
 342         }
 343         rc = smfs_init_dotinfo(snap_info);
 344 exit:
 345         if (rc && snap_table)
 346                 OBD_FREE(snap_table, table_size);
 347         RETURN(rc);
 348 }
 349
 350 static struct snap_info *smfs_create_snap_info(struct smfs_super_info *sinfo,
 351                                                struct inode *inode)
 352 {
 353         struct snap_info *snap_info = NULL;
 354         int rc = 0;
 355         ENTRY;
 356
 357         OBD_ALLOC(snap_info, sizeof(struct snap_info));
 358         if (!snap_info)
 359                 RETURN(ERR_PTR(-ENOMEM));
 360         rc = smfs_init_snap_info(sinfo, snap_info, inode);
 361         if (rc)
 362                 GOTO(exit, rc);
 363
 364         /*set cow flags for the snap root inode*/
 365         I2SMI(inode)->smi_flags |= SM_DO_COW;
 366         I2SNAPI(inode)->sn_root_ino = inode->i_ino;
 367 exit:
 368         if (rc) {
 369                 OBD_FREE(snap_info, sizeof(struct snap_info));
 370                 snap_info = ERR_PTR(rc);
 371         }
 372         RETURN(snap_info);
 373 }
 374
 375 static int smfs_cow_pre(struct inode *dir, void *dentry, void *new_dir,
 376                         void *new_dentry, int op);
 377
 378 static int smfs_cow_post(struct inode *dir, void *dentry, void *new_dir,
 379                          void *new_dentry, int op);
 380 #define COW_HOOK "cow_hook"
 381 static int smfs_cow_pre_hook(struct inode *inode, void *dentry, void *data1,
 382                              void *data2, int op, void *handle)
 383 {
 384         int rc = 0;
 385         ENTRY;
 386
 387         if (smfs_do_cow(inode)) {
 388                 /*FIXME:WANGDI, get index from the dentry*/
 389                 #if 0
 390                 int index = 0;
 391                 smfs_get_dentry_name_index(dentry, &name, index);
 392                 smfs_free_dentry_name(&name);
 393                 #endif
 394                 rc = smfs_cow_pre(inode, dentry, data1, data2, op);
 395         }
 396         RETURN(rc);
 397 }
 398 static int smfs_cow_post_hook(struct inode *inode, void *dentry, void *data1,
 399                               void *data2, int op, void *handle)
 400 {
 401         int rc = 0;
 402         ENTRY;
 403
 404         if (smfs_do_cow(inode)) {
 405                 rc = smfs_cow_post(inode, dentry, data1, data2, op);
 406         }
 407         RETURN(rc);
 408 }
 409
 410 int smfs_cow_cleanup(struct smfs_super_info *smb)
 411 {
 412         struct snap_super_info   *snap_sinfo = smb->smsi_snap_info;
 413         struct list_head         *snap_list = &snap_sinfo->snap_list;
 414         struct smfs_hook_ops     *cow_hops;
 415         int                      rc = 0;
 416         ENTRY;
 417
 418         while (!list_empty(snap_list)) {
 419                 struct snap_info *snap_info;
 420
 421                 snap_info = list_entry(snap_list->next, struct snap_info,
 422                                        sni_list);
 423                 rc = smfs_cleanup_snap_info(snap_info);
 424                 if (rc)
 425                         CERROR("cleanup snap_info error rc=%d\n", rc);
 426                 list_del(&snap_info->sni_list);
 427                 OBD_FREE(snap_info, sizeof(struct snap_info));
 428         }
 429
 430         if (snap_sinfo->snap_fsfilt)
 431                 fsfilt_put_ops(snap_sinfo->snap_fsfilt);
 432         if (snap_sinfo->snap_cache_fsfilt)
 433                 fsfilt_put_ops(snap_sinfo->snap_cache_fsfilt);
 434
 435         cow_hops = smfs_unregister_hook_ops(smb, COW_HOOK);
 436         smfs_free_hook_ops(cow_hops);
 437
 438         SMFS_CLEAN_COW(smb);
 439         if (snap_sinfo)
 440                OBD_FREE(snap_sinfo, sizeof(struct snap_super_info));
 441         RETURN(rc);
 442 }
 443
 444 int smfs_cow_init(struct super_block *sb)
 445 {
 446         struct smfs_super_info *smfs_info = S2SMI(sb);
 447         struct smfs_hook_ops *cow_hops = NULL;
 448         struct fsfilt_operations *sops;
 449         struct inode *root_inode = smfs_info->smsi_sb->s_root->d_inode;
 450         int snap_count = 0, rc = 0, vallen;
 451
 452         ENTRY;
 453
 454         SMFS_SET_COW(smfs_info);
 455
 456         cow_hops = smfs_alloc_hook_ops(COW_HOOK, smfs_cow_pre_hook,
 457                                        smfs_cow_post_hook);
 458         if (!cow_hops) {
 459                 RETURN(-ENOMEM);
 460         }
 461
 462         rc = smfs_register_hook_ops(smfs_info, cow_hops);
 463         if (rc) {
 464                 smfs_free_hook_ops(cow_hops);
 465                 RETURN(rc);
 466         }
 467
 468         rc = smfs_init_snap_super_info(smfs_info);
 469         if (rc && cow_hops) {
 470                 smfs_unregister_hook_ops(smfs_info, cow_hops->smh_name);
 471                 smfs_free_hook_ops(cow_hops);
 472                 RETURN(rc);
 473         }
 474         sops = smfs_info->smsi_snap_info->snap_cache_fsfilt;
 475
 476         vallen = sizeof(int);
 477         rc = sops->fs_get_snap_info(root_inode, SNAP_COUNT, strlen(SNAP_COUNT),
 478                                     &snap_count, &vallen);
 479         if (rc < 0)
 480                 GOTO(exit, rc);
 481
 482         if (snap_count > 0) {
 483                 int snap_root_size = snap_count * sizeof(ino_t);
 484                 ino_t *snap_root;
 485                 int i;
 486
 487                 OBD_ALLOC(snap_root, snap_root_size);
 488
 489                 if (!snap_root)
 490                         GOTO(exit, rc = -ENOMEM);
 491
 492                 rc = sops->fs_get_snap_info(root_inode, SNAP_ROOT_INO,
 493                                             strlen(SNAP_ROOT_INO), snap_root,
 494                                             &snap_root_size);
 495                 if (rc < 0) {
 496                         OBD_FREE(snap_root, sizeof(int) * snap_count);
 497                         GOTO(exit, rc);
 498                 }
 499                 for (i = 0; i < snap_count; i++) {
 500                         ino_t root_ino = le32_to_cpu(snap_root[i]);
 501                         struct snap_info *snap_info;
 502
 503                         root_inode = smfs_get_inode(sb, root_ino, NULL, 0);
 504                         smfs_init_snap_inode_info(root_inode, NULL, 0);
 505                         snap_info = smfs_create_snap_info(S2SMI(sb), root_inode);
 506                         iput(root_inode);
 507                         if (IS_ERR(snap_info)) {
 508                                 OBD_FREE(snap_root, sizeof(int) * snap_count);
 509                                 GOTO(exit, rc = PTR_ERR(snap_info));
 510                         }
 511                         list_add(&snap_info->sni_list,
 512                                  &(S2SNAPI(sb)->snap_list));
 513                 }
 514         }
 515         smfs_info->smsi_snap_info->snap_count = snap_count;
 516 exit:
 517         if (rc)
 518                 smfs_cow_cleanup(smfs_info);
 519         RETURN(rc);
 520 }
 521
 522 static int smfs_cleanup_dotinfo(struct snap_info *snap_info)
 523 {
 524         struct snap_dot_info *dot_info = NULL;
 525         int rc = 0;
 526         ENTRY;
 527
 528         if (!snap_info->sni_dot_info)
 529                 RETURN(rc);
 530
 531         dot_info = snap_info->sni_dot_info;
 532
 533         if (dot_info->dot_name) {
 534                 OBD_FREE(dot_info->dot_name, dot_info->dot_name_len + 1);
 535         }
 536
 537         OBD_FREE(dot_info, sizeof(struct snap_dot_info));
 538
 539         RETURN(rc);
 540 }
 541
 542 int smfs_cleanup_snap_info(struct snap_info *snap_info)
 543 {
 544         struct snap_table      *snap_table = snap_info->sni_table;
 545         int rc = 0, table_size;
 546         ENTRY;
 547
 548         l_dput(snap_info->sni_cowed_dentry);
 549         //d_unalloc(snap_info->sni_cowed_dentry);
 550         if (snap_table) {
 551                 table_size = SNAPTABLE_SIZE(snap_table->sntbl_max_count);
 552                 OBD_FREE(snap_info->sni_table, table_size);
 553         }
 554         smfs_cleanup_dotinfo(snap_info);
 555         RETURN(rc);
 556 }
 557
 558 int smfs_snap_test_inode(struct inode *inode, void *args)
 559 {
 560         struct smfs_iget_args *sargs = (struct smfs_iget_args*)args;
 561         struct inode *dir;
 562
 563         LASSERT(sargs);
 564
 565         dir = sargs->s_inode;
 566
 567         if (sargs->s_index > 0) {
 568                 if (I2SNAPI(inode)->sn_index != sargs->s_index)
 569                         return 0;
 570         }else {
 571                 if (dir && I2SNAPI(inode)->sn_index != I2SNAPI(dir)->sn_index)
 572                         return 0;
 573         }
 574         return 1;
 575 }
 576 /* latest snap: returns
 577    -  the index of the latest snapshot before NOW
 578    -  hence it returns 0 in case all the volume snapshots lie in the future
 579    -  this is the index where a COW will land (will be created)
 580 */
 581 void snap_last(struct inode *inode, struct snap *snap)
 582 {
 583         time_t now = LTIME_S(CURRENT_TIME);
 584         struct snap_table *snap_table;
 585         struct snap_info  *snap_info;
 586         int i ;
 587
 588         ENTRY;
 589
 590         snap_info = smfs_find_snap_info(inode);
 591         if (!snap_info) {
 592                 CDEBUG(D_INFO, "can not find snap info for inode %p\n", inode);
 593                 EXIT;
 594                 return;
 595         }
 596         snap_table = snap_info->sni_table;
 597         /* start at the highest index in the superblock snaptime array */
 598         if (snap_table->sntbl_count == 0) {
 599                memset(snap, 0, sizeof(struct snap));
 600         } else {
 601                 i = snap_table->sntbl_count - 1;
 602                 snap->sn_index = snap_table->sntbl_items[i].sn_index;
 603                 snap->sn_time = snap_table->sntbl_items[i].sn_time;
 604                 snap->sn_gen = snap_table->sntbl_items[i].sn_gen;
 605         }
 606         CDEBUG(D_INFO, "index: %d, time[i]: %ld, now: %ld\n",
 607                snap->sn_index, snap->sn_time, now);
 608         EXIT;
 609         return;
 610 }
 611
 612 static inline int get_index_of_item(struct snap_table *table, char *name)
 613 {
 614         int count = table->sntbl_count;
 615         int i, j;
 616         ENTRY;
 617
 618         for (i = 0; i < table->sntbl_max_count; i++) {
 619                 if (!strcmp(name, table->sntbl_items[i].sn_name)) {
 620                         CERROR("Duplicate name %s in snaptable\n", name);
 621                         RETURN(-EINVAL);
 622                 }
 623         }
 624
 625         for (i = 1; i <= table->sntbl_max_count; i++) {
 626                 int found = 0;
 627                 for (j = 0; j < (count + 1); j++) {
 628                         if (table->sntbl_items[j].sn_index == i) {
 629                                 found = 1;
 630                                 break;
 631                         }
 632                 }
 633                 if (!found)
 634                         RETURN(i);
 635         }
 636         CERROR("snaptable Full\n");
 637         RETURN(-ENOSPC);
 638 }
 639
 640 static struct dentry *smfs_find_snap_root(struct super_block *sb,
 641                                           char *path_name)
 642 {
 643         struct dentry *dentry = NULL;
 644         struct nameidata nd;
 645         ENTRY;
 646
 647 #if (LINUX_VERSION_CODE < KERNEL_VERSION(2,5,0))
 648         if (path_init(path_name, LOOKUP_FOLLOW, &nd)) {
 649                 int error = path_walk(path_name, &nd);
 650                 if (error) {
 651                         path_release(&nd);
 652                         RETURN(NULL);
 653                 }
 654         } else {
 655                 RETURN(NULL);
 656         }
 657 #else
 658         if (path_lookup(path_name, LOOKUP_FOLLOW, &nd))
 659                 RETURN(NULL);
 660 #endif
 661         dentry = dget(nd.dentry);
 662         path_release(&nd);
 663         RETURN(dentry);
 664 }
 665
 666 static int snap_add_item(struct smfs_super_info *smb,
 667                          struct snap_info *snap_info,
 668                          char *name)
 669 {
 670         struct fsfilt_operations *snapops;
 671         struct snap_table        *snap_table = snap_info->sni_table;
 672         struct inode             *root_inode = NULL;
 673         int                      table_size, count = 0, index = 0, rc = 0;
 674         struct  snap             *snap_item;
 675         ENTRY;
 676
 677         count = snap_table->sntbl_count;
 678         root_inode = iget(smb->smsi_sb, snap_info->sni_root_ino);
 679         if (!root_inode || is_bad_inode(root_inode))
 680                 RETURN(-EIO);
 681         /* XXX Is down this sema necessary*/
 682         down_interruptible(&snap_info->sni_sema);
 683         snap_item = &snap_table->sntbl_items[count];
 684         snapops = smb->smsi_snap_info->snap_cache_fsfilt;
 685         /*add item in snap_table set generation*/
 686         snap_item->sn_time = LTIME_S(CURRENT_TIME);
 687         /* find table index */
 688         index = get_index_of_item(snap_table, name);
 689         if (index < 0)
 690                 GOTO(exit, rc = index);
 691
 692         snap_item->sn_index = index;
 693         snap_item->sn_flags = 0;
 694         snap_item->sn_gen = snap_table->sntbl_generation + 1;
 695         memcpy(snap_item->sn_name, name, SNAP_MAX_NAMELEN);
 696         /* Wrote the whole snap_table to disk */
 697         table_size = SNAPTABLE_SIZE(snap_table->sntbl_max_count);
 698
 699         snap_table->sntbl_count++;
 700         snap_table->sntbl_generation++;
 701         rc = snapops->fs_set_snap_info(root_inode, SNAPTABLE_INFO,
 702                                        strlen(SNAPTABLE_INFO),
 703                                        snap_table, &table_size);
 704         if (rc) {
 705                 snap_table->sntbl_count--;
 706                 snap_table->sntbl_generation--;
 707                 CERROR("Set snaptable error rc=%d\n", rc);
 708                 GOTO(exit, rc);
 709         }
 710 exit:
 711         up(&snap_info->sni_sema);
 712         if (root_inode)
 713                 iput(root_inode);
 714         RETURN(rc);
 715 }
 716
 717 static struct snap_info * smfs_find_create_snap_info(struct super_block *sb,
 718                                                      struct inode *inode)
 719 {
 720         struct snap_super_info   *snap_sinfo = S2SNAPI(sb);
 721         struct fsfilt_operations *sops = snap_sinfo->snap_cache_fsfilt;
 722         struct snap_info *snap_info, *tmp;
 723         ino_t *snap_root = NULL;
 724         int    rino_size, snap_count_size, rc = 0;
 725         ENTRY;
 726
 727         list_for_each_entry_safe(snap_info, tmp, &snap_sinfo->snap_list,
 728                                  sni_list) {
 729                 if (snap_info->sni_root_ino == inode->i_ino) {
 730                         RETURN(snap_info);
 731                 }
 732         }
 733
 734         CDEBUG(D_INFO, "create a new  snap info root ino %lu\n", inode->i_ino);
 735
 736         snap_info = smfs_create_snap_info(S2SMI(sb), inode);
 737
 738         if (IS_ERR(snap_info))
 739                 RETURN(snap_info);
 740
 741         snap_sinfo->snap_count++;
 742
 743         rino_size = snap_sinfo->snap_count * sizeof(ino_t);
 744
 745         OBD_ALLOC(snap_root, rino_size);
 746
 747         if (!snap_root)
 748                 GOTO(exit, rc = -ENOMEM);
 749
 750         rc = sops->fs_get_snap_info(I2CI(inode), SNAP_ROOT_INO,
 751                                     strlen(SNAP_ROOT_INO), snap_root,
 752                                     &rino_size);
 753         if (rc < 0) {
 754                 if (rc == -ENODATA) {
 755                         rc = 0;
 756                 } else {
 757                         GOTO(exit, rc);
 758                 }
 759         }
 760         snap_root[snap_sinfo->snap_count - 1] = inode->i_ino;
 761
 762         snap_count_size = sizeof(int);
 763         rc = sops->fs_set_snap_info(I2CI(inode), SNAP_COUNT, strlen(SNAP_COUNT),
 764                                     &snap_sinfo->snap_count,  &snap_count_size);
 765         if (rc)
 766                 GOTO(exit, rc);
 767
 768         rc = sops->fs_set_snap_info(I2CI(inode), SNAP_ROOT_INO,
 769                                     strlen(SNAP_ROOT_INO), snap_root,
 770                                     &rino_size);
 771
 772         if (rc)
 773                 GOTO(exit, rc);
 774
 775         list_add(&snap_info->sni_list, &snap_sinfo->snap_list);
 776 exit:
 777         if (rc) {
 778                 smfs_cleanup_snap_info(snap_info);
 779                 OBD_FREE(snap_info, sizeof(struct snap_info));
 780         }
 781         if (snap_root)
 782                 OBD_FREE(snap_root, rino_size);
 783         RETURN(snap_info);
 784 }
 785
 786 int smfs_add_snap_item(struct super_block *sb, char *path_name, char *name)
 787 {
 788         struct dentry  *dentry = NULL;
 789         struct snap_info *snap_info;
 790         int            rc = 0;
 791         ENTRY;
 792
 793         if (!SMFS_DO_COW(S2SMI(sb))) {
 794                 RETURN(0);
 795         }
 796
 797         if (!path_name || !name) {
 798                 CERROR("patch_name and snapshot_name is NULL");
 799                 RETURN(-EINVAL);
 800         }
 801         dentry = smfs_find_snap_root(sb, path_name);
 802         if (IS_ERR(dentry)) {
 803                 CERROR("can not find snap_shot root by %s\n", path_name);
 804                 RETURN(PTR_ERR(dentry));
 805         }
 806         snap_info = smfs_find_create_snap_info(sb, dentry->d_inode);
 807         if (IS_ERR(snap_info)) {
 808                 CERROR("can not find snap_info by %s rc=%lu\n", path_name,
 809                         PTR_ERR(snap_info));
 810                 GOTO(exit, rc = PTR_ERR(snap_info));
 811         }
 812
 813         rc = snap_add_item(S2SMI(sb), snap_info, name);
 814 exit:
 815         dput(dentry);
 816         RETURN(rc);
 817 }
 818 //EXPORT_SYMBOL(smfs_add_snap_item);
 819 /*
 820  * Note: this function should be differnet with snap_do_cow.
 821  * In smfs_do_cow, we check the EA for whether do cow for that inode.
 822  * In smfs_needs_cow, we check whether we do need to do cow.
 823  */
 824 int smfs_needs_cow(struct inode *inode)
 825 {
 826         struct smfs_inode_info  *smi_info = I2SMI(inode);
 827         struct snap_inode_info *snap_info = NULL;
 828         struct snap snap;
 829         int index = -1;
 830         ENTRY;
 831
 832         snap_info = &(smi_info->sm_sninfo);
 833
 834         snap_last(inode, &snap);
 835         /* decision .... if the snapshot is more recent than the object,
 836          * then any change to the object should cause a COW.
 837          */
 838         if (snap_info->sn_gen < snap.sn_gen )
 839                 index = snap.sn_index;
 840
 841         CDEBUG(D_INFO, "snap_needs_cow, ino %lu , get index %d\n",
 842                inode->i_ino, index);
 843
 844         RETURN(index);
 845 } /* snap_needs_cow */
 846
 847 static int link_cowed_inode(struct inode *inode)
 848 {
 849         struct dentry *cowed_dir = NULL;
 850         char idname[LL_ID_NAMELEN];
 851         struct snap_info *snap_info;
 852         int idlen = 0, rc = 0;
 853         struct dentry *dchild = NULL;
 854         struct dentry *tmp = NULL;
 855         unsigned mode;
 856
 857         snap_info = smfs_find_snap_info(inode);
 858         if (!snap_info) {
 859                 CERROR("can not find snap info for inode %p\n", inode);
 860                 RETURN(-EINVAL);
 861         }
 862
 863         cowed_dir = snap_info->sni_cowed_dentry;
 864
 865         down(&cowed_dir->d_inode->i_sem);
 866
 867         idlen = ll_id2str(idname, inode->i_ino, inode->i_generation);
 868         dchild = lookup_one_len(idname, cowed_dir, idlen);
 869         if (IS_ERR(dchild)) {
 870                 rc = PTR_ERR(dchild);
 871                 if (rc != -EPERM && rc != -EACCES)
 872                         CERROR("child lookup error %d\n", rc);
 873                 GOTO(out_lock, rc);
 874         }
 875         if (dchild->d_inode != NULL) {
 876                 CERROR("re-cowed file %s?\n", dchild->d_name.name);
 877                 LASSERT(dchild->d_inode == inode);
 878                 GOTO(out_dput, rc = 0);
 879         }
 880         tmp = pre_smfs_dentry(NULL, inode, cowed_dir);
 881         /* link() is semanticaly-wrong for S_IFDIR, so we set S_IFREG
 882          * for linking and return real mode back then -bzzz */
 883         mode = inode->i_mode;
 884         inode->i_mode = S_IFREG;
 885
 886         rc = cowed_dir->d_inode->i_op->link(tmp, cowed_dir->d_inode, dchild);
 887
 888         post_smfs_dentry(tmp);
 889         if (rc) {
 890                 CERROR("error linking cowed inode %s to COWED: rc = %d\n",
 891                         idname, rc);
 892         }
 893         inode->i_mode = mode;
 894         if ((mode & S_IFMT) == S_IFDIR) {
 895                 dchild->d_inode->i_nlink++;
 896                 cowed_dir->d_inode->i_nlink++;
 897                 mark_inode_dirty(cowed_dir->d_inode);
 898                 mark_inode_dirty(dchild->d_inode);
 899         }
 900 out_dput:
 901         up(&cowed_dir->d_inode->i_sem);
 902         dput(dchild);
 903 out_lock:
 904         RETURN(rc);
 905 }
 906 /*
 907  * Make a copy of the data and plug a redirector in between if there
 908  * is no redirector yet.
 909  */
 910 int snap_do_cow(struct inode *inode, struct dentry *dparent, int del)
 911 {
 912         struct fsfilt_operations *snapops = I2SNAPCOPS(inode);
 913         struct snap snap;
 914         struct inode *cache_ind = NULL;
 915         ENTRY;
 916
 917         if (!snapops || !snapops->fs_create_indirect)
 918                 RETURN(-EINVAL);
 919
 920         snap_last(inode, &snap);
 921         cache_ind = snapops->fs_create_indirect(I2CI(inode), snap.sn_index,
 922                                           snap.sn_gen, I2CI(dparent->d_inode),
 923                                           del);
 924         if(cache_ind && IS_ERR(cache_ind)) {
 925                 CERROR("Create ind inode %lu index %d gen %d del %d rc%lu\n",
 926                         inode->i_ino, snap.sn_index, snap.sn_gen, del,
 927                         PTR_ERR(cache_ind));
 928                 RETURN(PTR_ERR(cache_ind));
 929         }
 930         if (cache_ind) {
 931                 iput(cache_ind);
 932                 if (!SMFS_DO_INODE_COWED(inode)) {
 933                         /*insert the inode to cowed inode*/
 934                         SMFS_SET_INODE_COWED(inode);
 935                         link_cowed_inode(inode);
 936                 }
 937         }
 938         RETURN(0);
 939 }
 940 /*Dir inode will do cow*/
 941 int smfs_cow_create_pre(struct inode *dir, void *de, void *data1, void *data2)
 942 {
 943         struct dentry *dparent;
 944         struct dentry *dentry = (struct dentry *)de;
 945         int rc = 0;
 946         ENTRY;
 947
 948         if (smfs_needs_cow(dir) != -1) {
 949                 CDEBUG(D_INODE, "snap_needs_cow for ino %lu \n",dir->i_ino);
 950                 LASSERT(dentry->d_parent && dentry->d_parent->d_parent);
 951                 dparent = dentry->d_parent->d_parent;
 952                 if ((rc = snap_do_cow(dir, dparent, 0))) {
 953                         CERROR("Do cow error %d\n", rc);
 954                         RETURN(-EINVAL);
 955                 }
 956         }
 957         RETURN(rc);
 958 }
 959
 960 int smfs_cow_setattr_pre(struct inode *dir, void *de, void *data1, void *data2)
 961 {
 962         struct dentry *dentry = (struct dentry *)de;
 963         int rc = 0;
 964         ENTRY;
 965         if (smfs_needs_cow(dir) != -1) {
 966                 CDEBUG(D_INODE, "snap_needs_cow for ino %lu \n",dir->i_ino);
 967                 if ((snap_do_cow(dir, dentry->d_parent, 0))) {
 968                         CERROR("Do cow error\n");
 969                         RETURN(-EINVAL);
 970                 }
 971         }
 972         RETURN(rc);
 973 }
 974
 975 int smfs_cow_link_pre(struct inode *dir, void *de, void *data1, void *data2)
 976 {
 977         struct dentry *dparent;
 978         struct dentry *dentry = (struct dentry *)de;
 979         int rc = 0;
 980         ENTRY;
 981
 982         if (smfs_needs_cow(dir) != -1) {
 983                 CDEBUG(D_INODE, "snap_needs_cow for ino %lu \n",dir->i_ino);
 984                 LASSERT(dentry->d_parent && dentry->d_parent->d_parent);
 985                 dparent = dentry->d_parent->d_parent;
 986                 if ((snap_do_cow(dir, dparent, 0))) {
 987                         CERROR("Do cow error\n");
 988                         RETURN(-EINVAL);
 989                 }
 990                 if ((snap_do_cow(dentry->d_inode, dentry->d_parent, 0))) {
 991                         CERROR("Do cow error\n");
 992                         RETURN(-EINVAL);
 993                 }
 994         }
 995         RETURN(rc);
 996 }
 997
 998 int smfs_cow_unlink_pre(struct inode *dir, void *de, void *data1, void *data2)
 999 {
1000         struct dentry *dentry = (struct dentry *)de;
1001         struct dentry *dparent;
1002         int rc = 0;
1003         ENTRY;
1004
1005         if (smfs_needs_cow(dir) != -1) {
1006                 CDEBUG(D_INODE, "snap_needs_cow for ino %lu \n",dir->i_ino);
1007                 LASSERT(dentry->d_parent && dentry->d_parent->d_parent);
1008                 dparent = dentry->d_parent->d_parent;
1009                 if ((snap_do_cow(dir, dparent, 0))) {
1010                         CERROR("Do cow error\n");
1011                         RETURN(-EINVAL);
1012                 }
1013                 if ((snap_do_cow(dentry->d_inode, dentry->d_parent, 1))) {
1014                         CERROR("Do cow error\n");
1015                         RETURN(-EINVAL);
1016                 }
1017
1018         }
1019         RETURN(rc);
1020 }
1021
1022 int smfs_cow_rename_pre(struct inode *dir, void *de, void *data1, void *data2)
1023 {
1024         struct dentry *dentry = (struct dentry*)de;
1025         struct inode *new_dir = (struct inode *)data1;
1026         struct dentry *new_dentry = (struct dentry *)data2;
1027         struct dentry *dparent;
1028         int rc = 0;
1029         ENTRY;
1030
1031         LASSERT(new_dir);
1032         LASSERT(new_dentry);
1033         if (smfs_needs_cow(dir) != -1) {
1034                 CDEBUG(D_INODE, "snap_needs_cow for ino %lu \n", dir->i_ino);
1035                 LASSERT(dentry->d_parent && dentry->d_parent->d_parent);
1036                 dparent = dentry->d_parent->d_parent;
1037                 if ((snap_do_cow(dir, dparent, 0))) {
1038                         CERROR("Do cow error\n");
1039                         RETURN(-EINVAL);
1040                 }
1041                 if ((snap_do_cow(dentry->d_inode, dentry->d_parent, 0))) {
1042                         CERROR("Do cow error\n");
1043                         RETURN(-EINVAL);
1044                 }
1045         }
1046         if (smfs_needs_cow(new_dir) != -1) {
1047                 CDEBUG(D_INODE, "snap_needs_cow for ino %lu \n", new_dir->i_ino);
1048                 LASSERT(new_dentry->d_parent && new_dentry->d_parent->d_parent);
1049                 dparent = new_dentry->d_parent->d_parent;
1050                 if ((new_dir != dir) && (snap_do_cow(new_dir, dparent, 0))){
1051                         CERROR("Do cow error\n");
1052                         RETURN(-EINVAL);
1053                 }
1054                 if (new_dentry->d_inode && new_dentry->d_inode->i_nlink == 1) {
1055                         if ((snap_do_cow(new_dentry->d_inode,
1056                                          new_dentry->d_parent, 0))) {
1057                                 CERROR("Do cow error\n");
1058                                 RETURN(-EINVAL);
1059                         }
1060                 }
1061         }
1062         RETURN(rc);
1063 }
1064
1065 int smfs_cow_write_pre(struct inode *inode, void *de, void *data1, void *data2)
1066 {
1067         struct dentry *dentry = (struct dentry*)de;
1068         struct snap_info *snap_info = NULL;
1069         struct snap_table *table;
1070         long   blocks[2]={-1,-1};
1071         int  index = 0, i, rc = 0;
1072         size_t count;
1073         loff_t pos;
1074
1075         ENTRY;
1076
1077         snap_info = smfs_find_snap_info(inode);
1078         if (!snap_info) {
1079                 CDEBUG(D_INFO, "can not find snap info for inode %p\n", inode);
1080                 RETURN(0);
1081         }
1082         table = snap_info->sni_table;
1083
1084         LASSERT(data1);
1085         LASSERT(data2);
1086
1087         count = *(size_t *)data1;
1088         pos = *(loff_t*)data2;
1089
1090         down(&inode->i_sem);
1091
1092         if (smfs_needs_cow(inode) != -1 ) {
1093                 CDEBUG(D_INFO, "snap_needs_cow for ino %lu \n",inode->i_ino);
1094                 snap_do_cow(inode, dentry->d_parent, 0);
1095         }
1096
1097         CDEBUG(D_INFO, "write offset %lld count %u \n", pos, count);
1098
1099         if(pos & (PAGE_CACHE_SIZE - 1)){
1100                 blocks[0] = pos >> inode->i_sb->s_blocksize_bits;
1101         }
1102         pos += count - 1;
1103         if((pos + 1) & (PAGE_CACHE_SIZE - 1)){
1104                 blocks[1] = pos >> inode->i_sb->s_blocksize_bits;
1105         }
1106
1107         if (blocks[0] == blocks[1])
1108                 blocks[1] = -1;
1109
1110         for (i = 0; i < 2; i++) {
1111                 int slot = 0;
1112                 if (blocks[i] == -1)
1113                         continue;
1114                 /*Find the nearest page in snaptable and copy back it*/
1115                 for (slot = table->sntbl_count - 1; slot >= 0; slot--) {
1116                         struct fsfilt_operations *sops = I2SNAPCOPS(inode);
1117                         struct inode *cind = NULL;
1118                         int result = 0;
1119
1120                         index = table->sntbl_items[slot].sn_index;
1121                         cind = sops->fs_get_indirect(I2CI(inode), NULL, index);
1122                         if (!cind)  continue;
1123
1124                         CDEBUG(D_INFO, "find cache_ino %lu\n", cind->i_ino);
1125
1126                         result = sops->fs_copy_block(I2CI(inode), cind,
1127                                                      blocks[i]);
1128                         if (result == 1) {
1129                                 iput(cind);
1130                                 result = 0;
1131                                 break;
1132                         }
1133                         if (result < 0) {
1134                                 iput(cind);
1135                                 up(&inode->i_sem);
1136                                 GOTO(exit, rc = result);
1137                         }
1138                         iput(cind);
1139                 }
1140         }
1141 exit:
1142         up(&inode->i_sem);
1143         RETURN(rc);
1144 }
1145 EXPORT_SYMBOL(smfs_cow_write_pre);
1146 /*lookup inode in dotsnap inode */
1147 static int smfs_dotsnap_lookup(struct inode *dir, struct dentry *dentry,
1148                                struct snap_info *snap_info)
1149 {
1150         if (dentry->d_name.len == 1 &&
1151             !strcmp(dentry->d_name.name, ".")) {
1152                 d_add(dentry, iget(dir->i_sb, dir->i_ino));
1153         } else if (dentry->d_name.len == 2 &&
1154                    !strcmp(dentry->d_name.name, "..")) {
1155                 struct inode *inode;
1156                 struct dentry *dparent = dentry->d_parent;
1157                 if (dparent->d_inode) {
1158                         inode = iget(dir->i_sb, dparent->d_inode->i_ino);
1159                         if (inode) {
1160                                 if (!is_bad_inode(inode))
1161                                         d_add(dentry, inode);
1162                                 else
1163                                         iput(inode);
1164                         }
1165                 }
1166         } else {
1167                 /*find the name from the snaptable*/
1168                 struct fsfilt_operations *sops = I2SNAPCOPS(dir);
1169                 struct snap_table *table;
1170                 struct inode *inode;
1171                 ino_t  cino;
1172                 int i = 0, index = -1;
1173
1174                 table = snap_info->sni_table;
1175
1176                 for (i = 0; i < table->sntbl_count; i++) {
1177                         char *name = table->sntbl_items[i].sn_name;
1178                         if ((dentry->d_name.len == strlen(name)) &&
1179                             (memcmp(dentry->d_name.name, name,
1180                                     dentry->d_name.len) == 0)) {
1181                                 index = table->sntbl_items[i].sn_index;
1182                                 break;
1183                         }
1184                 }
1185                 if (index == -1) {
1186                        CERROR("No such %s in this .snap dir \n",
1187                                dentry->d_name.name);
1188                        RETURN(-ENOENT);
1189                 }
1190                 cino = sops->fs_get_indirect_ino(S2CSB(dir->i_sb), dir->i_ino,
1191                                                  index);
1192                 if (cino == 0)
1193                         cino = dir->i_ino;
1194                 inode = smfs_get_inode(dir->i_sb, cino, dir, index);
1195                 if (!inode || is_bad_inode(inode)) {
1196                         CERROR("Can not find cino %lu inode\n", cino);
1197                         RETURN(-ENOENT);
1198                 }
1199                 smfs_init_snap_inode_info(inode, dir, index);
1200                 d_add(dentry, inode);
1201         }
1202         RETURN(0);
1203 }
1204 int smfs_cow_lookup_pre(struct inode *inode, void *de, void *data1,
1205                         void *data2)
1206 {
1207         struct dentry *dentry = (struct dentry*)de;
1208         struct snap_info *snap_info;
1209         struct snap_dot_info *dot_info;
1210         int rc = 0;
1211         ENTRY;
1212
1213         snap_info = smfs_find_snap_info(inode);
1214         if (!snap_info) {
1215                 CDEBUG(D_INFO, "can not find snap info for inode %p\n", inode);
1216                 RETURN(0);
1217         }
1218
1219         dot_info = snap_info->sni_dot_info;
1220
1221         if (smfs_primary_inode(inode) &&
1222             dentry->d_name.len == dot_info->dot_name_len &&
1223             memcmp(dentry->d_name.name, dot_info->dot_name,
1224                    strlen(dot_info->dot_name)) == 0) {
1225                 struct inode *dot_inode = NULL;
1226
1227                 dot_inode = smfs_get_inode(inode->i_sb, inode->i_ino, inode,
1228                                            DOT_SNAP_INDEX);
1229                 smfs_init_snap_inode_info(dot_inode, inode, DOT_SNAP_INDEX);
1230                 d_add(dentry, dot_inode);
1231                 rc = 1;
1232                 RETURN(rc);
1233         } else if (smfs_dotsnap_inode(inode)) {
1234                 rc = smfs_dotsnap_lookup(inode, dentry, snap_info);
1235                 if (rc == 0)
1236                         rc = 1;
1237                 RETURN(rc);
1238         } else {
1239                 /*HERE: will replace ino in dentry->d_name according to index,
1240                  *For iopen, will fix it in integrating snapfs to Lustre*/
1241 #if 0
1242                 struct fsfilt_operations *snapops = I2SNAPOPS(inode);
1243                 char *name = (char *)dentry->d_name.name;
1244                 unsigned long ino, hash, ind_ino;
1245                 int len = sizeof(ind_ino);
1246
1247                 ino = simple_strtoul(name, 0, 0);
1248
1249                 ind_ino = snapops->fs_get_indirect_ino(inode->i_sb, ino, index);
1250
1251                 snprintf(name, strlen(name), "0x%lx", ind_ino);
1252
1253                 hash = init_name_hash();
1254                 while (len--) {
1255                         unsigned char c;
1256                         c = *(const unsigned char *)name++;
1257                         if (c == '\0') break;
1258                         hash = partial_name_hash(c, hash);
1259                 }
1260                 dentry->d_name.hash = end_name_hash(hash);
1261 #endif
1262         }
1263         RETURN(rc);
1264 }
1265
1266 struct inode *smfs_cow_get_ind(struct inode *inode, int index)
1267 {
1268         long block=(index << PAGE_CACHE_SHIFT) >> inode->i_sb->s_blocksize_bits;
1269         struct fsfilt_operations *sops = I2SNAPCOPS(inode);
1270         struct snap_info *snap_info = NULL;
1271         struct snap_table *table = NULL;
1272         int slot;
1273
1274         ENTRY;
1275
1276         snap_info = smfs_find_snap_info(inode);
1277         if (!snap_info) {
1278                 CDEBUG(D_INFO, "can not find snap info for inode %p\n", inode);
1279                 RETURN(NULL);
1280         }
1281
1282         table = snap_info->sni_table;
1283
1284         for (slot = table->sntbl_count - 1; slot >= 0; slot--) {
1285                 struct address_space_operations *aops = inode->i_mapping->a_ops;
1286                 struct inode *cache_inode = NULL;
1287                 int index = 0;
1288
1289                 index = table->sntbl_items[slot].sn_index;
1290                 cache_inode = sops->fs_get_indirect(I2CI(inode), NULL, index);
1291
1292                 if (!cache_inode )  continue;
1293
1294                 if (aops->bmap(cache_inode->i_mapping, block))
1295                        RETURN(cache_inode);
1296                 iput(cache_inode);
1297         }
1298
1299         RETURN(NULL);
1300 }
1301 EXPORT_SYMBOL(smfs_cow_get_ind);
1302
1303 static int smfs_cow_readdir_pre(struct inode *dir, void *de, void *data1,
1304                                 void *data2)
1305 {
1306         struct file *filp = (struct file*)de;
1307         void *dirent = data1;
1308         filldir_t filldir = (filldir_t)data2;
1309         struct snap_info *snap_info = NULL;
1310
1311         if (smfs_under_dotsnap_inode(dir))
1312                 RETURN(0);
1313
1314         snap_info = smfs_find_snap_info(dir);
1315
1316         if (!snap_info) {
1317                 CDEBUG(D_INFO, "can not find snap info for ino %lu\n",
1318                        dir->i_ino);
1319                 RETURN(-EINVAL);
1320         }
1321
1322         if (smfs_primary_inode(dir)) {
1323                 if (filp->f_pos == 0) {
1324                         struct snap_dot_info *dot = snap_info->sni_dot_info;
1325                         if (filldir(dirent, dot->dot_name, dot->dot_name_len,
1326                                     filp->f_pos, -1, 0)) {
1327                                 CERROR("fill .snap error \n");
1328                                 RETURN(-EINVAL);
1329                         }
1330                 } else {
1331                         filp->f_pos -= 1;
1332                 }
1333         } else if (smfs_dotsnap_inode(dir)) {
1334                 struct snap_table *table = snap_info->sni_table;
1335                 int i = 0;
1336
1337                 if (filp->f_pos < 0)
1338                        RETURN(-EINVAL);
1339
1340                 if ((filp->f_pos == 0) && filldir(dirent, ".", 1,
1341                                                   filp->f_pos++,
1342                                                   dir->i_ino, 0) < 0)
1343                        RETURN(-EIO);
1344                 if ((filp->f_pos == 1) && filldir(dirent, "..", 2,
1345                                                   filp->f_pos++,
1346                                                   dir->i_ino, 0) < 0)
1347                        RETURN(-EIO);
1348
1349                 for (i = filp->f_pos - 2; i < table->sntbl_count; i++,
1350                      filp->f_pos++) {
1351                         int slot = table->sntbl_count - i - 1;
1352
1353                         if (filldir(dirent, table->sntbl_items[slot].sn_name,
1354                                     strlen(table->sntbl_items[slot].sn_name),
1355                                     filp->f_pos, dir->i_ino, 0))
1356                                 break;
1357
1358                 }
1359                 RETURN(1);
1360         }
1361
1362         RETURN(0);
1363 }
1364
1365
1366 typedef int (*cow_funcs)(struct inode *dir, void *dentry, void *new_dir,
1367                          void *new_dentry);
1368
1369 static cow_funcs smfs_cow_pre_funcs[HOOK_MAX + 1] = {
1370         [HOOK_CREATE]   smfs_cow_create_pre,
1371         [HOOK_LOOKUP]   smfs_cow_lookup_pre,
1372         [HOOK_LINK]     smfs_cow_link_pre,
1373         [HOOK_UNLINK]   smfs_cow_unlink_pre,
1374         [HOOK_SYMLINK]  smfs_cow_create_pre,
1375         [HOOK_MKDIR]    smfs_cow_create_pre,
1376         [HOOK_RMDIR]    smfs_cow_unlink_pre,
1377         [HOOK_MKNOD]    smfs_cow_create_pre,
1378         [HOOK_RENAME]   smfs_cow_rename_pre,
1379         [HOOK_SETATTR]  smfs_cow_setattr_pre,
1380         [HOOK_WRITE]    smfs_cow_write_pre,
1381         [HOOK_READDIR]  smfs_cow_readdir_pre,
1382 };
1383
1384 static int smfs_revalidate_dotsnap_dentry(struct dentry *dentry,
1385                                           struct inode *dir, int index)
1386 {
1387         struct inode *inode = dentry->d_inode;
1388         ENTRY;
1389
1390         if (!inode)
1391                 RETURN(0);
1392
1393         if (index > 0 && index != DOT_SNAP_INDEX) {
1394                 struct fsfilt_operations *sops = I2SNAPCOPS(inode);
1395                 struct inode *cache_ind = NULL;
1396
1397                 cache_ind = sops->fs_get_indirect(I2CI(inode), NULL, index);
1398
1399                 if (cache_ind) {
1400                         struct inode *ind_inode = NULL;
1401
1402                         LASSERT(cache_ind->i_ino != I2CI(inode)->i_ino);
1403
1404                         ind_inode = smfs_get_inode(inode->i_sb, cache_ind->i_ino,
1405                                                    dir, index);
1406                         list_del_init(&dentry->d_alias);
1407                         iput(inode);
1408                         d_instantiate(dentry, ind_inode);
1409                         iput(cache_ind);
1410                 }
1411         }
1412         RETURN(0);
1413 }
1414
1415 #if (LINUX_VERSION_CODE > KERNEL_VERSION(2,5,0))
1416 static int
1417 smfs_revalidate_nd(struct dentry *de, struct nameidata *nd)
1418 {
1419         struct inode *inode = de->d_inode;
1420         ENTRY;
1421
1422         if (!inode)
1423                 RETURN(0);
1424
1425         if (smfs_under_dotsnap_inode(inode)) {
1426                 struct inode *dir = de->d_parent->d_inode;
1427                 int index = I2SNAPI(inode)->sn_index;
1428
1429                 smfs_revalidate_dotsnap_dentry(de, dir, index);
1430                 smfs_init_snap_inode_info(de->d_inode, dir, index);
1431         }
1432
1433         RETURN(0);
1434 }
1435 #else
1436 static int
1437 smfs_revalidate_it(struct dentry *de, int flags,
1438                    struct nameidata *nd,
1439                    struct lookup_intent *it)
1440 {
1441         struct inode *inode = de->d_inode;
1442         ENTRY;
1443
1444         if (!inode)
1445                 RETURN(0);
1446
1447         if (smfs_under_dotsnap_inode(inode)) {
1448                 struct inode *dir = de->d_parent->d_inode;
1449                 int index = I2SNAPI(inode)->sn_index;
1450
1451                 smfs_revalidate_dotsnap_dentry(de, dir, index);
1452                 smfs_init_snap_inode_info(de->d_inode, dir, index);
1453         }
1454
1455         RETURN(0);
1456 }
1457 #endif
1458
1459 static int smfs_delete_dentry(struct dentry *dentry)
1460 {
1461         dentry->d_op = NULL;
1462         return 0;
1463 }
1464
1465 struct dentry_operations smfs_cow_dops = {
1466 #if (LINUX_VERSION_CODE > KERNEL_VERSION(2,5,0))
1467         .d_revalidate = smfs_revalidate_nd,
1468 #else
1469         .d_revalidate_it = smfs_revalidate_it,
1470 #endif
1471         .d_delete     = smfs_delete_dentry,
1472 };
1473
1474 int smfs_cow_lookup_post(struct inode *dir, void *de, void *data1,
1475                          void *data2)
1476 {
1477         struct dentry *dentry = (struct dentry*)de;
1478         struct inode *inode = dentry->d_inode;
1479         ENTRY;
1480
1481         if (inode && smfs_under_dotsnap_inode(inode)) {
1482                 int index = I2SNAPI(dir)->sn_index;
1483
1484                 smfs_revalidate_dotsnap_dentry(dentry, dir, index);
1485                 smfs_init_snap_inode_info(inode, dir, index);
1486         }
1487         dentry->d_op = &smfs_cow_dops;
1488         RETURN(0);
1489 }
1490
1491 static int smfs_cow_readdir_post(struct inode *dir, void *de, void *data1,
1492                                  void *data2)
1493 {
1494         struct file *filp = (struct file*)de;
1495
1496         if (smfs_primary_inode(dir)) {
1497                 filp->f_pos += 1;
1498         }
1499         RETURN(0);
1500 }
1501
1502
1503 static cow_funcs smfs_cow_post_funcs[HOOK_MAX + 1] = {
1504         [HOOK_CREATE]   NULL,
1505         [HOOK_LOOKUP]   smfs_cow_lookup_post,
1506         [HOOK_LINK]     NULL,
1507         [HOOK_UNLINK]   NULL,
1508         [HOOK_SYMLINK]  NULL,
1509         [HOOK_MKDIR]    NULL,
1510         [HOOK_RMDIR]    NULL,
1511         [HOOK_MKNOD]    NULL,
1512         [HOOK_RENAME]   NULL,
1513         [HOOK_SETATTR]  NULL,
1514         [HOOK_WRITE]    NULL,
1515         [HOOK_READDIR]  smfs_cow_readdir_post,
1516 };
1517
1518 static int smfs_cow_pre(struct inode *dir, void *dentry, void *new_dir,
1519                         void *new_dentry, int op)
1520 {
1521         if (smfs_cow_pre_funcs[op]) {
1522                 return smfs_cow_pre_funcs[op](dir, dentry, new_dir, new_dentry);
1523         }
1524         return 0;
1525 }
1526
1527 static int smfs_cow_post(struct inode *dir, void *dentry, void *new_dir,
1528                          void *new_dentry, int op)
1529 {
1530         if (smfs_cow_post_funcs[op]) {
1531                 return smfs_cow_post_funcs[op](dir, dentry, new_dir, new_dentry);
1532         }
1533         return 0;
1534 }
1535