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 static int smfs_init_snap_super_info(struct smfs_super_info *smfs_info)
  47 {
  48         struct snap_super_info  *snap_sinfo;
  49         int rc = 0;
  50
  51         ENTRY;
  52
  53         OBD_ALLOC(smfs_info->smsi_snap_info, sizeof(struct snap_super_info));
  54         if (!smfs_info->smsi_snap_info)
  55                 GOTO(exit, rc = -ENOMEM);
  56
  57         snap_sinfo = smfs_info->smsi_snap_info;
  58
  59         /*init snap fsfilt operations*/
  60         if (!snap_sinfo->snap_cache_fsfilt) {
  61                 char *snap_cache_ftype = NULL;
  62                 int   tmp = strlen(smfs_info->smsi_cache_ftype) + strlen("_snap");
  63
  64                 OBD_ALLOC(snap_cache_ftype, tmp + 1);
  65                 sprintf(snap_cache_ftype, "%s_snap", smfs_info->smsi_cache_ftype);
  66                 snap_sinfo->snap_cache_fsfilt = fsfilt_get_ops(snap_cache_ftype);
  67                 OBD_FREE(snap_cache_ftype, tmp + 1);
  68                 if (!snap_sinfo->snap_cache_fsfilt) {
  69                         CERROR("Can not get %s fsfilt ops needed by snap\n",
  70                                snap_cache_ftype);
  71                         GOTO(exit, rc = -EINVAL);
  72                 }
  73         }
  74         if (!snap_sinfo->snap_fsfilt) {
  75                 char *snap_ftype = NULL;
  76                 int   tmp = strlen(smfs_info->smsi_ftype) + strlen("_snap");
  77
  78                 OBD_ALLOC(snap_ftype, tmp + 1);
  79                 sprintf(snap_ftype, "%s_snap", smfs_info->smsi_ftype);
  80                 snap_sinfo->snap_fsfilt = fsfilt_get_ops(snap_ftype);
  81                 OBD_FREE(snap_ftype, tmp + 1);
  82                 if (!snap_sinfo->snap_fsfilt) {
  83                         CERROR("Can not get %s fsfilt ops needed by snap\n",
  84                                snap_ftype);
  85                         GOTO(exit, rc = -EINVAL);
  86                 }
  87         }
  88         INIT_LIST_HEAD(&snap_sinfo->snap_list);
  89 exit:
  90         if (rc && smfs_info->smsi_snap_info)
  91                 OBD_FREE(snap_sinfo, sizeof(struct snap_super_info));
  92         RETURN(rc);
  93 }
  94 /*FIXME-wangdi Should remove it when integrated it with lustre*/
  95 static struct dentry *smfs_simple_mkdir(struct dentry *dir, char *name,
  96                                         int mode, int fix)
  97 {
  98         struct dentry *dchild;
  99         int err = 0;
 100
 101         dchild = ll_lookup_one_len(name, dir, strlen(name));
 102         if (IS_ERR(dchild))
 103                 GOTO(out_up, dchild);
 104
 105         if (dchild->d_inode) {
 106                 int old_mode = dchild->d_inode->i_mode;
 107                 if (!S_ISDIR(old_mode))
 108                         GOTO(out_err, err = -ENOTDIR);
 109
 110                 /* Fixup directory permissions if necessary */
 111                 if (fix && (old_mode & S_IALLUGO) != (mode & S_IALLUGO)) {
 112                         CWARN("fixing permissions on %s from %o to %o\n",
 113                               name, old_mode, mode);
 114                         dchild->d_inode->i_mode = (mode & S_IALLUGO) |
 115                                                   (old_mode & ~S_IALLUGO);
 116                         mark_inode_dirty(dchild->d_inode);
 117                 }
 118                 GOTO(out_up, dchild);
 119         }
 120         err = vfs_mkdir(dir->d_inode, dchild, mode);
 121         if (err)
 122                 GOTO(out_err, err);
 123         RETURN(dchild);
 124 out_err:
 125         dput(dchild);
 126         dchild = ERR_PTR(err);
 127 out_up:
 128         return dchild;
 129
 130 }
 131 static struct snap_info *smfs_find_snap_info(struct inode *inode)
 132 {
 133         struct snap_inode_info *snap_iinfo = I2SNAPI(inode);
 134         struct snap_super_info *snap_sinfo = S2SNAPI(inode->i_sb);
 135         struct snap_info *snap_info = NULL, *tmp;
 136
 137         ENTRY;
 138         list_for_each_entry_safe(snap_info, tmp, &snap_sinfo->snap_list,
 139                                  sni_list) {
 140                if (snap_info->sni_root_ino == snap_iinfo->sn_root_ino)
 141                         RETURN(snap_info);
 142         }
 143         RETURN(NULL);
 144 }
 145
 146 static int smfs_dotsnap_dir_size(struct inode *inode)
 147 {
 148         struct snap_super_info *snap_sinfo = S2SNAPI(inode->i_sb);
 149         struct fsfilt_operations *snapops = snap_sinfo->snap_cache_fsfilt;
 150         int size = 0, dir_size = 0, blocks, i = 0;
 151         struct snap_table *snap_table = NULL;
 152         struct snap_info *snap_info = NULL;
 153         ENTRY;
 154
 155         snap_info = smfs_find_snap_info(inode);
 156
 157         if (!snap_info) {
 158                 CDEBUG(D_INFO, "can not find snap info for inode %p\n", inode);
 159                 RETURN(0);
 160         }
 161         snap_table = snap_info->sni_table;
 162         for (i = 0; i < snap_table->sntbl_count; i++) {
 163                 char *name = snap_table->sntbl_items[i].sn_name;
 164                 size += snapops->fs_dir_ent_size(name);
 165         }
 166         /*FIXME this is only for ext3 dir format, may need fix for other FS*/
 167         blocks = (size + inode->i_sb->s_blocksize - 1) >>
 168                                 inode->i_sb->s_blocksize_bits;
 169
 170         dir_size = blocks * inode->i_sb->s_blocksize;
 171         RETURN(dir_size);
 172
 173 }
 174
 175 static int smfs_init_snap_inode_info(struct inode *inode, struct inode *dir, int index)
 176 {
 177         int rc = 0;
 178         ENTRY;
 179
 180         if (dir) {
 181                 I2SNAPI(inode)->sn_flags = I2SNAPI(dir)->sn_flags;
 182                 I2SNAPI(inode)->sn_gen = I2SNAPI(dir)->sn_gen;
 183                 I2SNAPI(inode)->sn_root_ino = I2SNAPI(dir)->sn_root_ino;
 184                 I2SNAPI(inode)->sn_index = I2SNAPI(inode)->sn_index;
 185         } else {
 186                 I2SNAPI(inode)->sn_flags = 0;
 187                 I2SNAPI(inode)->sn_gen = 0;
 188         }
 189
 190         I2SNAPI(inode)->sn_index = index;
 191
 192         if (smfs_dotsnap_inode(inode)) {
 193                 struct snap_info *snap_info;
 194
 195                 snap_info = smfs_find_snap_info(inode);
 196                 if (!snap_info) {
 197                         RETURN(-EIO);
 198                 }
 199                 /*init dot_snap inode info*/
 200                 inode->i_size = (loff_t)smfs_dotsnap_dir_size(inode);
 201                 inode->i_nlink = snap_info->sni_table->sntbl_count + 2;
 202                 inode->i_uid = 0;
 203                 inode->i_gid = 0;
 204         } else if (SMFS_DO_COW(S2SMI(inode->i_sb)) &&
 205                    (I2SMI(inode)->smi_flags & SM_DO_COW) &&
 206                    smfs_primary_inode(inode)) {
 207                 struct snap_inode_info *sni_info = I2SNAPI(inode);
 208                 struct fsfilt_operations *sops = I2SNAPCOPS(inode);
 209                 int vallen = 0;
 210
 211                 vallen = sizeof(sni_info->sn_gen);
 212
 213                 rc = sops->fs_get_snap_info(I2CI(inode), SNAP_GENERATION,
 214                                             strlen(SNAP_GENERATION),
 215                                             &sni_info->sn_gen, &vallen);
 216         }
 217         RETURN(rc);
 218 }
 219
 220 #define COWED_NAME_LEN       (7 + 8 + 1)
 221 static int smfs_init_cowed_dir(struct snap_info *snap_info, struct dentry* dir)
 222 {
 223         struct dentry    *dentry = NULL;
 224         char   name[COWED_NAME_LEN];
 225         int    rc = 0;
 226         ENTRY;
 227
 228         sprintf(name, ".cowed_%08x", (__u32)dir->d_inode->i_ino);
 229         /*FIXME-WANGDI: will use simple_mkdir, when integrating snap to lustre*/
 230         dentry = smfs_simple_mkdir(dir, name, 0777, 1);
 231         if (IS_ERR(dentry)) {
 232                 rc = PTR_ERR(dentry);
 233                 CERROR("create cowed directory: rc = %d\n", rc);
 234                 RETURN(rc);
 235         }
 236         snap_info->sni_cowed_dentry = dentry;
 237         RETURN(rc);
 238 }
 239
 240 static int smfs_init_dotinfo(struct snap_info *snap_info)
 241 {
 242         struct snap_dot_info *dot_info = NULL;
 243         int rc = 0;
 244         ENTRY;
 245
 246         if (snap_info->sni_dot_info)
 247                 RETURN(-EEXIST);
 248
 249         OBD_ALLOC(snap_info->sni_dot_info, sizeof(struct snap_dot_info));
 250
 251         if (!snap_info->sni_dot_info)
 252                 RETURN(-ENOMEM);
 253
 254         dot_info = snap_info->sni_dot_info;
 255
 256         OBD_ALLOC(dot_info->dot_name,  strlen(DOT_SNAP_NAME) + 1);
 257
 258         if (!dot_info->dot_name) {
 259                 OBD_FREE(snap_info->sni_dot_info, sizeof(struct snap_dot_info));
 260                 RETURN(-ENOMEM);
 261         }
 262         memcpy(dot_info->dot_name, DOT_SNAP_NAME, strlen(DOT_SNAP_NAME));
 263
 264         dot_info->dot_name_len = strlen(DOT_SNAP_NAME);
 265         dot_info->dot_snap_enable = 1;
 266
 267         RETURN(rc);
 268 }
 269
 270 static int smfs_init_snap_info(struct smfs_super_info *smb,
 271                                struct snap_info *snap_info, struct dentry *de)
 272 {
 273         struct snap_table        *snap_table = NULL;
 274         struct fsfilt_operations *snapcops;
 275         int                      rc = 0, size, table_size, vallen, i;
 276         struct inode             *root_inode = NULL;
 277
 278         ENTRY;
 279
 280         root_inode = iget(smb->smsi_sb, de->d_inode->i_ino);
 281         if (!root_inode || is_bad_inode(root_inode))
 282                 RETURN(-EIO);
 283         snapcops = smb->smsi_snap_info->snap_cache_fsfilt;
 284         /*Initialized table */
 285         /*get the maxsize of snaptable*/
 286         vallen = sizeof(int);
 287         rc = snapcops->fs_get_snap_info(root_inode, MAX_SNAPTABLE_COUNT,
 288                                        strlen(MAX_SNAPTABLE_COUNT), &size,
 289                                        &vallen);
 290         if (size == 0) {
 291                 CERROR("the Max snaptable count should not be zero\n");
 292                 GOTO(exit, rc);
 293         }
 294         table_size = SNAPTABLE_SIZE(size);
 295
 296         OBD_ALLOC(snap_info->sni_table, table_size);
 297
 298         if (!snap_info->sni_table) {
 299                 CERROR("No MEM\n");
 300                 RETURN(-ENOMEM);
 301         }
 302         snap_table = snap_info->sni_table;
 303
 304         snap_table->sntbl_magic = cpu_to_le32((__u32)SNAPTABLE_MAGIC);
 305         snap_table->sntbl_max_count = size;
 306         /*init sn_index to -1*/
 307         for (i = 0; i < snap_table->sntbl_max_count; i++)
 308                 snap_table->sntbl_items[i].sn_index = -1;
 309         /*get snaptable info*/
 310         rc = snapcops->fs_get_snap_info(root_inode, SNAPTABLE_INFO,
 311                                         strlen(SNAPTABLE_INFO),
 312                                         snap_table, &table_size);
 313         if (rc < 0) {
 314                 if (rc == -ENODATA) {
 315                         snap_table->sntbl_count = 0;
 316                 } else {
 317                         CERROR("Can not retrive the snaptable from this filesystem\n");
 318                         GOTO(exit, rc);
 319                 }
 320         } else {
 321                 if (le32_to_cpu(snap_table->sntbl_magic) != SNAPTABLE_MAGIC) {
 322                         CERROR("On disk snaptable is not right \n");
 323                         GOTO(exit, rc = -EIO);
 324                 }
 325         }
 326         init_MUTEX(&snap_info->sni_sema);
 327         snap_info->sni_root_ino = de->d_inode->i_ino;
 328         rc = smfs_init_cowed_dir(snap_info, de);
 329         if (rc) {
 330                 CERROR("Init cowed dir error rc=%d\n", rc);
 331                 GOTO(exit, rc);
 332         }
 333         rc = smfs_init_dotinfo(snap_info);
 334 exit:
 335         if (root_inode)
 336                 iput(root_inode);
 337         if (rc && snap_table)
 338                 OBD_FREE(snap_table, table_size);
 339         RETURN(rc);
 340 }
 341
 342 static struct snap_info *smfs_create_snap_info(struct smfs_super_info *sinfo,
 343                                                struct dentry *dentry)
 344 {
 345         struct snap_info *snap_info = NULL;
 346         int rc = 0;
 347         ENTRY;
 348
 349         OBD_ALLOC(snap_info, sizeof(struct snap_info));
 350         if (!snap_info)
 351                 RETURN(ERR_PTR(-ENOMEM));
 352         rc = smfs_init_snap_info(sinfo, snap_info, dentry);
 353         if (rc)
 354                 GOTO(exit, snap_info = ERR_PTR(rc));
 355
 356         /*set cow flags for the snap root inode*/
 357         I2SMI(dentry->d_inode)->smi_flags |= SM_DO_COW;
 358         I2SNAPI(dentry->d_inode)->sn_root_ino = dentry->d_inode->i_ino;
 359 exit:
 360         if (rc)
 361                 OBD_FREE(snap_info, sizeof(struct snap_info));
 362         RETURN(snap_info);
 363 }
 364
 365 static int smfs_cow_pre(struct inode *dir, struct dentry *dentry, void *new_dir,
 366                         void *new_dentry, int op);
 367
 368 static int smfs_cow_post(struct inode *dir, struct dentry *dentry, void *new_dir,
 369                          void *new_dentry, int op);
 370 #define COW_HOOK "cow_hook"
 371 static int smfs_cow_pre_hook(struct inode *inode, struct dentry *dentry,
 372                              void *data1, void *data2, int op, void *handle)
 373 {
 374         int rc = 0;
 375         ENTRY;
 376
 377         if (smfs_do_cow(inode)) {
 378                 /*FIXME:WANGDI, get index from the dentry*/
 379                 #if 0
 380                 int index = 0;
 381                 smfs_get_dentry_name_index(dentry, &name, index);
 382                 smfs_free_dentry_name(&name);
 383                 #endif
 384                 rc = smfs_cow_pre(inode, dentry, data1, data2, op);
 385         }
 386         RETURN(rc);
 387 }
 388 static int smfs_cow_post_hook(struct inode *inode, struct dentry *dentry,
 389                               void *data1, void *data2, int op, void *handle)
 390 {
 391         int rc = 0;
 392         ENTRY;
 393
 394         if (smfs_do_cow(inode)) {
 395                 rc = smfs_cow_post(inode, dentry, data1, data2, op);
 396         }
 397         RETURN(rc);
 398 }
 399
 400 int smfs_cow_init(struct super_block *sb)
 401 {
 402         struct smfs_super_info *smfs_info = S2SMI(sb);
 403         struct smfs_hook_ops *cow_hops = NULL;
 404         struct fsfilt_operations *sops;
 405         struct inode *root_inode = smfs_info->smsi_sb->s_root->d_inode;
 406         int snap_count = 0, rc = 0, vallen;
 407
 408         ENTRY;
 409
 410         SMFS_SET_COW(smfs_info);
 411
 412         cow_hops = smfs_alloc_hook_ops(COW_HOOK, smfs_cow_pre_hook,
 413                                        smfs_cow_post_hook);
 414         if (!cow_hops) {
 415                 RETURN(-ENOMEM);
 416         }
 417
 418         rc = smfs_register_hook_ops(smfs_info, cow_hops);
 419         if (rc) {
 420                 smfs_free_hook_ops(cow_hops);
 421                 RETURN(rc);
 422         }
 423
 424         rc = smfs_init_snap_super_info(smfs_info);
 425         if (rc && cow_hops) {
 426                 smfs_unregister_hook_ops(smfs_info, cow_hops->smh_name);
 427                 smfs_free_hook_ops(cow_hops);
 428                 RETURN(rc);
 429         }
 430         sops = smfs_info->smsi_snap_info->snap_cache_fsfilt;
 431
 432         vallen = sizeof(int);
 433         rc = sops->fs_get_snap_info(root_inode, SNAP_COUNT, strlen(SNAP_COUNT),
 434                                     &snap_count, &vallen);
 435         if (rc)
 436                 GOTO(exit, rc);
 437
 438         if (snap_count > 0) {
 439                 int snap_root_size = snap_count * sizeof(ino_t);
 440                 ino_t *snap_root;
 441                 int i;
 442
 443                 OBD_ALLOC(snap_root, snap_root_size);
 444
 445                 if (!snap_root)
 446                         GOTO(exit, rc = -ENOMEM);
 447
 448                 rc = sops->fs_get_snap_info(root_inode, SNAP_ROOT_INO,
 449                                             strlen(SNAP_ROOT_INO), snap_root,
 450                                             &snap_root_size);
 451                 if (rc) {
 452                         OBD_FREE(snap_root, sizeof(int) * snap_count);
 453                         GOTO(exit, rc);
 454                 }
 455                 for (i = 0; i < snap_count; i++) {
 456                         ino_t root_ino = le32_to_cpu(snap_root[i]);
 457                         struct dentry *tmp = smfs_info->smsi_sb->s_root;
 458                         struct snap_info *snap_info;
 459                         struct dentry *dentry;
 460
 461                         root_inode = smfs_get_inode(sb, root_ino, NULL, 0);
 462                         smfs_init_snap_inode_info(root_inode, NULL, 0);
 463                         dentry = pre_smfs_dentry(NULL, root_inode, tmp);
 464                         snap_info = smfs_create_snap_info(S2SMI(sb), dentry);
 465                         post_smfs_dentry(dentry);
 466                         if (IS_ERR(snap_info)) {
 467                                 OBD_FREE(snap_root, sizeof(int) * snap_count);
 468                                 GOTO(exit, rc = PTR_ERR(snap_info));
 469                         }
 470                         list_add(&snap_info->sni_list,
 471                                  &(S2SNAPI(sb)->snap_list));
 472                 }
 473         }
 474 exit:
 475         if (rc)
 476                 smfs_cow_cleanup(smfs_info);
 477
 478         RETURN(rc);
 479 }
 480
 481 static int smfs_cleanup_dotinfo(struct snap_info *snap_info)
 482 {
 483         struct snap_dot_info *dot_info = NULL;
 484         int rc = 0;
 485         ENTRY;
 486
 487         if (!snap_info->sni_dot_info)
 488                 RETURN(rc);
 489
 490         dot_info = snap_info->sni_dot_info;
 491
 492         if (dot_info->dot_name) {
 493                 OBD_FREE(dot_info->dot_name, dot_info->dot_name_len + 1);
 494         }
 495
 496         OBD_FREE(dot_info, sizeof(struct snap_dot_info));
 497
 498         RETURN(rc);
 499 }
 500
 501 int smfs_cleanup_snap_info(struct snap_info *snap_info)
 502 {
 503         struct snap_table      *snap_table = snap_info->sni_table;
 504         int rc = 0, table_size;
 505         ENTRY;
 506
 507         l_dput(snap_info->sni_cowed_dentry);
 508         if (snap_table) {
 509                 table_size = SNAPTABLE_SIZE(snap_table->sntbl_max_count);
 510                 OBD_FREE(snap_info->sni_table, table_size);
 511         }
 512         smfs_cleanup_dotinfo(snap_info);
 513         RETURN(rc);
 514 }
 515
 516 int smfs_cow_cleanup(struct smfs_super_info *smb)
 517 {
 518         struct snap_super_info   *snap_sinfo = smb->smsi_snap_info;
 519         struct list_head         *snap_list = &snap_sinfo->snap_list;
 520         struct smfs_hook_ops     *cow_hops;
 521         int                      rc = 0;
 522         ENTRY;
 523
 524         while (!list_empty(snap_list)) {
 525                 struct snap_info *snap_info;
 526
 527                 snap_info = list_entry(snap_list->next, struct snap_info,
 528                                        sni_list);
 529                 rc = smfs_cleanup_snap_info(snap_info);
 530                 if (rc)
 531                         CERROR("cleanup snap_info error rc=%d\n", rc);
 532                 list_del(&snap_info->sni_list);
 533                 OBD_FREE(snap_info, sizeof(struct snap_info));
 534         }
 535
 536         if (snap_sinfo->snap_fsfilt)
 537                 fsfilt_put_ops(snap_sinfo->snap_fsfilt);
 538         if (snap_sinfo->snap_cache_fsfilt)
 539                 fsfilt_put_ops(snap_sinfo->snap_cache_fsfilt);
 540
 541         cow_hops = smfs_unregister_hook_ops(smb, COW_HOOK);
 542         smfs_free_hook_ops(cow_hops);
 543
 544         SMFS_CLEAN_COW(smb);
 545         if (snap_sinfo)
 546                OBD_FREE(snap_sinfo, sizeof(struct snap_super_info));
 547         RETURN(rc);
 548 }
 549
 550 int smfs_snap_test_inode(struct inode *inode, void *args)
 551 {
 552         struct smfs_iget_args *sargs = (struct smfs_iget_args*)args;
 553         struct inode *dir;
 554
 555         LASSERT(sargs);
 556
 557         dir = sargs->s_inode;
 558
 559         if (sargs->s_index > 0) {
 560                 if (I2SNAPI(inode)->sn_index != sargs->s_index)
 561                         return 0;
 562         }else {
 563                 if (dir && I2SNAPI(inode)->sn_index != I2SNAPI(dir)->sn_index)
 564                         return 0;
 565         }
 566         return 1;
 567 }
 568 /* latest snap: returns
 569    -  the index of the latest snapshot before NOW
 570    -  hence it returns 0 in case all the volume snapshots lie in the future
 571    -  this is the index where a COW will land (will be created)
 572 */
 573 void snap_last(struct inode *inode, struct snap *snap)
 574 {
 575         time_t now = LTIME_S(CURRENT_TIME);
 576         struct snap_table *snap_table;
 577         struct snap_info  *snap_info;
 578         int i ;
 579
 580         ENTRY;
 581
 582         snap_info = smfs_find_snap_info(inode);
 583         if (!snap_info) {
 584                 CDEBUG(D_INFO, "can not find snap info for inode %p\n", inode);
 585                 EXIT;
 586                 return;
 587         }
 588         snap_table = snap_info->sni_table;
 589         /* start at the highest index in the superblock snaptime array */
 590         if (snap_table->sntbl_count == 0) {
 591                memset(snap, 0, sizeof(struct snap));
 592         } else {
 593                 i = snap_table->sntbl_count - 1;
 594                 snap->sn_index = snap_table->sntbl_items[i].sn_index;
 595                 snap->sn_time = snap_table->sntbl_items[i].sn_time;
 596                 snap->sn_gen = snap_table->sntbl_items[i].sn_gen;
 597         }
 598         CDEBUG(D_INFO, "index: %d, time[i]: %ld, now: %ld\n",
 599                snap->sn_index, snap->sn_time, now);
 600         EXIT;
 601         return;
 602 }
 603
 604 static inline int get_index_of_item(struct snap_table *table, char *name)
 605 {
 606         int count = table->sntbl_count;
 607         int i, j;
 608         ENTRY;
 609
 610         for (i = 0; i < table->sntbl_max_count; i++) {
 611                 if (!strcmp(name, table->sntbl_items[i].sn_name)) {
 612                         CERROR("Duplicate name %s in snaptable\n", name);
 613                         RETURN(-EINVAL);
 614                 }
 615         }
 616
 617         for (i = 0; i < table->sntbl_max_count; i++) {
 618                 int found = 0;
 619                 for (j = 0; j < (count + 1); j++) {
 620                         if (table->sntbl_items[j].sn_index == i) {
 621                                 found = 1;
 622                                 break;
 623                         }
 624                 }
 625                 if (!found)
 626                         RETURN(i);
 627         }
 628         CERROR("snaptable Full\n");
 629         RETURN(-ENOSPC);
 630 }
 631
 632 static struct dentry *smfs_find_snap_root(struct super_block *sb,
 633                                           char *path_name)
 634 {
 635         struct dentry *dentry = NULL;
 636         struct nameidata nd;
 637         ENTRY;
 638
 639 #if (LINUX_VERSION_CODE < KERNEL_VERSION(2,5,0))
 640         if (path_init(path_name, LOOKUP_FOLLOW, &nd)) {
 641                 error = path_walk(path_name, &nd);
 642                 if (error) {
 643                         path_release(&nd);
 644                         RETURN(NULL);
 645                 }
 646         } else {
 647                 RETURN(NULL);
 648         }
 649 #else
 650         if (path_lookup(path_name, LOOKUP_FOLLOW, &nd))
 651                 RETURN(NULL);
 652
 653 #endif
 654         dentry = dget(nd.dentry);
 655         path_release(&nd);
 656         RETURN(dentry);
 657 }
 658 static int snap_add_item(struct smfs_super_info *smb,
 659                          struct snap_info *snap_info,
 660                          char *name)
 661 {
 662         struct fsfilt_operations *snapops;
 663         struct snap_table        *snap_table = snap_info->sni_table;
 664         struct inode             *root_inode = NULL;
 665         int                      table_size, count = 0, index = 0, rc = 0;
 666         struct  snap             *snap_item;
 667         ENTRY;
 668
 669         count = snap_table->sntbl_count;
 670         root_inode = iget(smb->smsi_sb, snap_info->sni_root_ino);
 671         if (!root_inode || is_bad_inode(root_inode))
 672                 RETURN(-EIO);
 673         /* XXX Is down this sema necessary*/
 674         down_interruptible(&snap_info->sni_sema);
 675         snap_item = &snap_table->sntbl_items[count];
 676         snapops = smb->smsi_snap_info->snap_cache_fsfilt;
 677         /*add item in snap_table set generation*/
 678         snap_item->sn_time = LTIME_S(CURRENT_TIME);
 679         /* find table index */
 680         index = get_index_of_item(snap_table, name);
 681         if (index < 0)
 682                 GOTO(exit, rc = index);
 683
 684         snap_item->sn_index = index;
 685         snap_item->sn_flags = 0;
 686         snap_item->sn_gen = snap_table->sntbl_generation + 1;
 687         memcpy(snap_item->sn_name, name, SNAP_MAX_NAMELEN);
 688         /* Wrote the whole snap_table to disk */
 689         table_size = SNAPTABLE_SIZE(snap_table->sntbl_max_count);
 690
 691         rc = snapops->fs_set_snap_info(root_inode, SNAPTABLE_INFO,
 692                                        strlen(SNAPTABLE_INFO),
 693                                        snap_table, &table_size);
 694         if (rc) {
 695                 CERROR("Set snaptable error rc=%d\n", rc);
 696                 GOTO(exit, rc);
 697         }
 698         snap_table->sntbl_count++;
 699         snap_table->sntbl_generation++;
 700 exit:
 701         up(&snap_info->sni_sema);
 702         if (root_inode)
 703                 iput(root_inode);
 704         RETURN(rc);
 705 }
 706
 707 static struct snap_info * smfs_find_create_snap_info(struct super_block *sb,
 708                                                      struct dentry *dentry)
 709 {
 710         struct snap_super_info   *snap_sinfo = S2SNAPI(sb);
 711         struct snap_info *snap_info, *tmp;
 712         ENTRY;
 713
 714         list_for_each_entry_safe(snap_info, tmp, &snap_sinfo->snap_list,
 715                                  sni_list) {
 716                 if (snap_info->sni_root_ino == dentry->d_inode->i_ino) {
 717                         RETURN(snap_info);
 718                 }
 719         }
 720
 721         CDEBUG(D_INFO, "create a new  snap info root ino %lu\n",
 722                dentry->d_inode->i_ino);
 723
 724         snap_info = smfs_create_snap_info(S2SMI(sb), dentry);
 725
 726         if (IS_ERR(snap_info))
 727                 RETURN(snap_info);
 728
 729         list_add(&snap_info->sni_list, &snap_sinfo->snap_list);
 730         RETURN(snap_info);
 731 }
 732
 733 int smfs_add_snap_item(struct super_block *sb, char *path_name, char *name)
 734 {
 735         struct dentry  *dentry = NULL;
 736         struct snap_info *snap_info;
 737         int            rc = 0;
 738         ENTRY;
 739
 740         if (!SMFS_DO_COW(S2SMI(sb))) {
 741                 RETURN(0);
 742         }
 743
 744         if (!path_name || !name) {
 745                 CERROR("patch_name and snapshot_name is NULL");
 746                 RETURN(-EINVAL);
 747         }
 748         dentry = smfs_find_snap_root(sb, path_name);
 749         if (IS_ERR(dentry)) {
 750                 CERROR("can not find snap_shot root by %s\n", path_name);
 751                 RETURN(PTR_ERR(dentry));
 752         }
 753         snap_info = smfs_find_create_snap_info(sb, dentry);
 754         if (IS_ERR(snap_info)) {
 755                 CERROR("can not find snap_info by %s rc=%lu\n", path_name,
 756                         PTR_ERR(snap_info));
 757                 GOTO(exit, rc = PTR_ERR(snap_info));
 758         }
 759
 760         rc = snap_add_item(S2SMI(sb), snap_info, name);
 761 exit:
 762         dput(dentry);
 763         RETURN(rc);
 764 }
 765 //EXPORT_SYMBOL(smfs_add_snap_item);
 766 /*
 767  * Note: this function should be differnet with snap_do_cow.
 768  * In smfs_do_cow, we check the EA for whether do cow for that inode.
 769  * In smfs_needs_cow, we check whether we do need to do cow.
 770  */
 771 int smfs_needs_cow(struct inode *inode)
 772 {
 773         struct smfs_inode_info  *smi_info = I2SMI(inode);
 774         struct snap_inode_info *snap_info = NULL;
 775         struct snap snap;
 776         int index = -1;
 777         ENTRY;
 778
 779         snap_info = &(smi_info->sm_sninfo);
 780
 781         snap_last(inode, &snap);
 782         /* decision .... if the snapshot is more recent than the object,
 783          * then any change to the object should cause a COW.
 784          */
 785         if (snap_info->sn_gen < snap.sn_gen )
 786                 index = snap.sn_index;
 787
 788         CDEBUG(D_INFO, "snap_needs_cow, ino %lu , get index %d\n",
 789                inode->i_ino, index);
 790
 791         RETURN(index);
 792 } /* snap_needs_cow */
 793
 794 static int link_cowed_inode(struct inode *inode)
 795 {
 796         struct dentry *cowed_dir = NULL;
 797         char fidname[LL_FID_NAMELEN];
 798         struct snap_info *snap_info;
 799         int fidlen = 0, rc = 0;
 800         struct dentry *dchild = NULL;
 801         struct dentry *tmp = NULL;
 802         unsigned mode;
 803
 804         snap_info = smfs_find_snap_info(inode);
 805         if (!snap_info) {
 806                 CERROR("can not find snap info for inode %p\n", inode);
 807                 RETURN(-EINVAL);
 808         }
 809
 810         cowed_dir = snap_info->sni_cowed_dentry;
 811
 812         fidlen = ll_fid2str(fidname, inode->i_ino, inode->i_generation);
 813
 814         down(&cowed_dir->d_inode->i_sem);
 815         dchild = ll_lookup_one_len(fidname, cowed_dir, fidlen);
 816         if (IS_ERR(dchild)) {
 817                 rc = PTR_ERR(dchild);
 818                 if (rc != -EPERM && rc != -EACCES)
 819                         CERROR("child lookup error %d\n", rc);
 820                 GOTO(out_lock, rc);
 821         }
 822         if (dchild->d_inode != NULL) {
 823                 CERROR("re-cowed file %s?\n", dchild->d_name.name);
 824                 LASSERT(dchild->d_inode == inode);
 825                 GOTO(out_dput, rc = 0);
 826         }
 827         tmp = pre_smfs_dentry(NULL, inode, cowed_dir);
 828         /* link() is semanticaly-wrong for S_IFDIR, so we set S_IFREG
 829          * for linking and return real mode back then -bzzz */
 830         mode = inode->i_mode;
 831         inode->i_mode = S_IFREG;
 832         rc = vfs_link(tmp, cowed_dir->d_inode, dchild);
 833         post_smfs_dentry(tmp);
 834         if (rc) {
 835                 CERROR("error linking cowed inode %s to COWED: rc = %d\n",
 836                         fidname, rc);
 837         }
 838         inode->i_mode = mode;
 839         if ((mode & S_IFMT) == S_IFDIR) {
 840                 dchild->d_inode->i_nlink++;
 841                 cowed_dir->d_inode->i_nlink++;
 842         }
 843         mark_inode_dirty(dchild->d_inode);
 844 out_dput:
 845         dput(dchild);
 846 out_lock:
 847         up(&cowed_dir->d_inode->i_sem);
 848         RETURN(rc);
 849 }
 850 /*
 851  * Make a copy of the data and plug a redirector in between if there
 852  * is no redirector yet.
 853  */
 854 int snap_do_cow(struct inode *inode, struct dentry *dparent, int del)
 855 {
 856         struct fsfilt_operations *snapops = I2SNAPCOPS(inode);
 857         struct snap snap;
 858         struct inode *cache_ind = NULL;
 859         ENTRY;
 860
 861         if (!snapops || !snapops->fs_create_indirect)
 862                 RETURN(-EINVAL);
 863
 864         snap_last(inode, &snap);
 865         cache_ind = snapops->fs_create_indirect(I2CI(inode), snap.sn_index,
 866                                           snap.sn_gen, I2CI(dparent->d_inode),
 867                                           del);
 868         if(cache_ind && IS_ERR(cache_ind)) {
 869                 CERROR("Create ind inode %lu index %d gen %d del %d rc%lu\n",
 870                         inode->i_ino, snap.sn_index, snap.sn_gen, del,
 871                         PTR_ERR(cache_ind));
 872                 RETURN(PTR_ERR(cache_ind));
 873         }
 874         iput(cache_ind);
 875         if (!SMFS_DO_INODE_COWED(inode)) {
 876                 /*insert the inode to cowed inode*/
 877                 SMFS_SET_INODE_COWED(inode);
 878                 link_cowed_inode(inode);
 879         }
 880         RETURN(0);
 881 }
 882 /*Dir inode will do cow*/
 883 int smfs_cow_create(struct inode *dir, struct dentry *dentry,
 884                     void *data1, void *data2)
 885 {
 886         int rc = 0;
 887         struct dentry *dparent;
 888         ENTRY;
 889
 890         if (smfs_needs_cow(dir) != -1) {
 891                 CDEBUG(D_INODE, "snap_needs_cow for ino %lu \n",dir->i_ino);
 892                 LASSERT(dentry->d_parent && dentry->d_parent->d_parent);
 893                 dparent = dentry->d_parent->d_parent;
 894                 if ((rc = snap_do_cow(dir, dparent, 0))) {
 895                         CERROR("Do cow error %d\n", rc);
 896                         RETURN(-EINVAL);
 897                 }
 898         }
 899         RETURN(rc);
 900 }
 901
 902 int smfs_cow_setattr(struct inode *dir, struct dentry *dentry,
 903                      void *data1, void *data2)
 904 {
 905         int rc = 0;
 906         ENTRY;
 907         if (smfs_needs_cow(dir) != -1) {
 908                 CDEBUG(D_INODE, "snap_needs_cow for ino %lu \n",dir->i_ino);
 909                 if ((snap_do_cow(dir, dentry->d_parent, 0))) {
 910                         CERROR("Do cow error\n");
 911                         RETURN(-EINVAL);
 912                 }
 913         }
 914         RETURN(rc);
 915 }
 916
 917 int smfs_cow_link(struct inode *dir, struct dentry *dentry,
 918                   void *data1, void *data2)
 919 {
 920         int rc = 0;
 921         struct dentry *dparent;
 922         ENTRY;
 923
 924         if (smfs_needs_cow(dir) != -1) {
 925                 CDEBUG(D_INODE, "snap_needs_cow for ino %lu \n",dir->i_ino);
 926                 LASSERT(dentry->d_parent && dentry->d_parent->d_parent);
 927                 dparent = dentry->d_parent->d_parent;
 928                 if ((snap_do_cow(dir, dparent, 0))) {
 929                         CERROR("Do cow error\n");
 930                         RETURN(-EINVAL);
 931                 }
 932                 if ((snap_do_cow(dentry->d_inode, dentry->d_parent, 0))) {
 933                         CERROR("Do cow error\n");
 934                         RETURN(-EINVAL);
 935                 }
 936         }
 937         RETURN(rc);
 938 }
 939
 940 int smfs_cow_unlink(struct inode *dir, struct dentry *dentry,
 941                     void *data1, void *data2)
 942 {
 943         struct dentry *dparent;
 944         int rc = 0;
 945         ENTRY;
 946
 947         if (smfs_needs_cow(dir) != -1) {
 948                 CDEBUG(D_INODE, "snap_needs_cow for ino %lu \n",dir->i_ino);
 949                 LASSERT(dentry->d_parent && dentry->d_parent->d_parent);
 950                 dparent = dentry->d_parent->d_parent;
 951                 if ((snap_do_cow(dir, dparent, 0))) {
 952                         CERROR("Do cow error\n");
 953                         RETURN(-EINVAL);
 954                 }
 955                 if ((snap_do_cow(dentry->d_inode, dentry->d_parent, 1))) {
 956                         CERROR("Do cow error\n");
 957                         RETURN(-EINVAL);
 958                 }
 959
 960         }
 961         RETURN(rc);
 962 }
 963
 964 int smfs_cow_rename(struct inode *dir, struct dentry *dentry,
 965                     void *data1, void *data2)
 966 {
 967         struct inode *new_dir = (struct inode *)data1;
 968         struct dentry *new_dentry = (struct dentry *)data2;
 969         struct dentry *dparent;
 970         int rc = 0;
 971         ENTRY;
 972
 973         LASSERT(new_dir);
 974         LASSERT(new_dentry);
 975         if (smfs_needs_cow(dir) != -1) {
 976                 CDEBUG(D_INODE, "snap_needs_cow for ino %lu \n", dir->i_ino);
 977                 LASSERT(dentry->d_parent && dentry->d_parent->d_parent);
 978                 dparent = dentry->d_parent->d_parent;
 979                 if ((snap_do_cow(dir, dparent, 0))) {
 980                         CERROR("Do cow error\n");
 981                         RETURN(-EINVAL);
 982                 }
 983                 if ((snap_do_cow(dentry->d_inode, dentry->d_parent, 0))) {
 984                         CERROR("Do cow error\n");
 985                         RETURN(-EINVAL);
 986                 }
 987         }
 988         if (smfs_needs_cow(new_dir) != -1) {
 989                 CDEBUG(D_INODE, "snap_needs_cow for ino %lu \n", new_dir->i_ino);
 990                 LASSERT(new_dentry->d_parent && new_dentry->d_parent->d_parent);
 991                 dparent = new_dentry->d_parent->d_parent;
 992                 if ((new_dir != dir) && (snap_do_cow(new_dir, dparent, 0))){
 993                         CERROR("Do cow error\n");
 994                         RETURN(-EINVAL);
 995                 }
 996                 if (new_dentry->d_inode && new_dentry->d_inode->i_nlink == 1) {
 997                         if ((snap_do_cow(new_dentry->d_inode,
 998                                          new_dentry->d_parent, 0))) {
 999                                 CERROR("Do cow error\n");
1000                                 RETURN(-EINVAL);
1001                         }
1002                 }
1003         }
1004         RETURN(rc);
1005 }
1006
1007 int smfs_cow_write(struct inode *inode, struct dentry *dentry, void *data1,
1008                    void *data2)
1009 {
1010         struct snap_info *snap_info = NULL;
1011         struct snap_table *table;
1012         long   blocks[2]={-1,-1};
1013         int  index = 0, i, rc = 0;
1014         size_t count;
1015         loff_t pos;
1016
1017         ENTRY;
1018
1019         snap_info = smfs_find_snap_info(inode);
1020         if (!snap_info) {
1021                 CDEBUG(D_INFO, "can not find snap info for inode %p\n", inode);
1022                 RETURN(0);
1023         }
1024         table = snap_info->sni_table;
1025
1026         LASSERT(data1);
1027         LASSERT(data2);
1028
1029         count = *(size_t *)data1;
1030         pos = *(loff_t*)data2;
1031
1032         down(&inode->i_sem);
1033
1034         if (smfs_needs_cow(inode) != -1 ) {
1035                 CDEBUG(D_INFO, "snap_needs_cow for ino %lu \n",inode->i_ino);
1036                 snap_do_cow(inode, dentry->d_parent, 0);
1037         }
1038
1039         CDEBUG(D_INFO, "write offset %lld count %u \n", pos, count);
1040
1041         if(pos & (PAGE_CACHE_SIZE - 1)){
1042                 blocks[0] = pos >> inode->i_sb->s_blocksize_bits;
1043         }
1044         pos += count - 1;
1045         if((pos + 1) & (PAGE_CACHE_SIZE - 1)){
1046                 blocks[1] = pos >> inode->i_sb->s_blocksize_bits;
1047         }
1048
1049         if (blocks[0] == blocks[1])
1050                 blocks[1] = -1;
1051
1052         for (i = 0; i < 2; i++) {
1053                 int slot = 0;
1054                 if (blocks[i] == -1)
1055                         continue;
1056                 /*Find the nearest page in snaptable and copy back it*/
1057                 for (slot = table->sntbl_count - 1; slot >= 0; slot--) {
1058                         struct fsfilt_operations *sops = I2SNAPCOPS(inode);
1059                         struct inode *cind = NULL;
1060                         int result = 0;
1061
1062                         index = table->sntbl_items[slot].sn_index;
1063                         cind = sops->fs_get_indirect(I2CI(inode), NULL, index);
1064                         if (!cind)  continue;
1065
1066                         CDEBUG(D_INFO, "find cache_ino %lu\n", cind->i_ino);
1067
1068                         result = sops->fs_copy_block(I2CI(inode), cind,
1069                                                      blocks[i]);
1070                         if (result == 1) {
1071                                 iput(cind);
1072                                 result = 0;
1073                                 break;
1074                         }
1075                         if (result < 0) {
1076                                 iput(cind);
1077                                 up(&inode->i_sem);
1078                                 GOTO(exit, rc = result);
1079                         }
1080                         iput(cind);
1081                 }
1082         }
1083 exit:
1084         up(&inode->i_sem);
1085         RETURN(rc);
1086 }
1087 EXPORT_SYMBOL(smfs_cow_write);
1088 /*lookup inode in dotsnap inode */
1089 static int smfs_dotsnap_lookup(struct inode *dir, struct dentry *dentry,
1090                                struct snap_info *snap_info)
1091 {
1092         if (dentry->d_name.len == 1 &&
1093             !strcmp(dentry->d_name.name, ".")) {
1094                 d_add(dentry, iget(dir->i_sb, dir->i_ino));
1095         } else if (dentry->d_name.len == 2 &&
1096                    !strcmp(dentry->d_name.name, "..")) {
1097                 struct inode *inode;
1098                 struct dentry *dparent = dentry->d_parent;
1099                 if (dparent->d_inode) {
1100                         inode = iget(dir->i_sb, dparent->d_inode->i_ino);
1101                         if (inode) {
1102                                 if (!is_bad_inode(inode))
1103                                         d_add(dentry, inode);
1104                                 else
1105                                         iput(inode);
1106                         }
1107                 }
1108         } else {
1109                 /*find the name from the snaptable*/
1110                 struct fsfilt_operations *sops = I2SNAPCOPS(dir);
1111                 struct snap_table *table;
1112                 struct inode *inode;
1113                 ino_t  cino;
1114                 int i = 0, index = -1;
1115
1116                 table = snap_info->sni_table;
1117
1118                 for (i = 0; i < table->sntbl_count; i++) {
1119                         char *name = table->sntbl_items[i].sn_name;
1120                         if ((dentry->d_name.len == strlen(name)) &&
1121                             (memcmp(dentry->d_name.name, name,
1122                                     dentry->d_name.len) == 0)) {
1123                                 index = table->sntbl_items[i].sn_index;
1124                                 break;
1125                         }
1126                 }
1127                 if (index != -1) {
1128                        CERROR("No such %s in this .snap dir \n",
1129                                dentry->d_name.name);
1130                        RETURN(-ENOENT);
1131                 }
1132                 cino = sops->fs_get_indirect_ino(S2CSB(dir->i_sb), dir->i_ino,
1133                                                  index);
1134                 inode = smfs_get_inode(dir->i_sb, cino, dir, index);
1135                 if (!inode || is_bad_inode(inode)) {
1136                         CERROR("Can not find cino %lu inode\n", cino);
1137                         RETURN(-ENOENT);
1138                 }
1139                 smfs_init_snap_inode_info(inode, dir, index);
1140                 d_add(dentry, inode);
1141         }
1142         RETURN(0);
1143 }
1144 int smfs_cow_lookup(struct inode *inode, struct dentry *dentry, void *data1,
1145                     void *data2)
1146 {
1147         struct snap_info *snap_info;
1148         struct snap_dot_info *dot_info;
1149         int rc = 0, index = 0;
1150         ENTRY;
1151
1152         snap_info = smfs_find_snap_info(inode);
1153         if (!snap_info) {
1154                 CDEBUG(D_INFO, "can not find snap info for inode %p\n", inode);
1155                 RETURN(0);
1156         }
1157
1158         dot_info = snap_info->sni_dot_info;
1159
1160         LASSERT(dot_info != NULL);
1161         LASSERT(data1 != NULL);
1162
1163         index = *(int *)data1;
1164
1165         if (smfs_primary_inode(inode) &&
1166             dentry->d_name.len == dot_info->dot_name_len &&
1167             memcmp(dentry->d_name.name, dot_info->dot_name,
1168                    strlen(dot_info->dot_name)) == 0) {
1169                 struct inode *dot_inode = NULL;
1170
1171                 dot_inode = smfs_get_inode(inode->i_sb, inode->i_ino, inode,
1172                                            DOT_SNAP_INDEX);
1173                 smfs_init_snap_inode_info(dot_inode, inode, DOT_SNAP_INDEX);
1174                 d_add(dentry, dot_inode);
1175                 rc = 1;
1176                 RETURN(rc);
1177         }
1178         if (smfs_dotsnap_inode(inode)) {
1179                 rc = smfs_dotsnap_lookup(inode, dentry, snap_info);
1180                 if (rc == 0)
1181                         rc = 1;
1182                 RETURN(rc);
1183         }
1184         if (index > 0) {
1185                 /*HERE: will replace ino in dentry->d_name according to index*/
1186                 struct fsfilt_operations *snapops = I2SNAPOPS(inode);
1187                 char *name = (char *)dentry->d_name.name;
1188                 unsigned long ino, hash, ind_ino;
1189                 int len = sizeof(ind_ino);
1190
1191                 ino = simple_strtoul(name, 0, 0);
1192
1193                 ind_ino = snapops->fs_get_indirect_ino(inode->i_sb, ino, index);
1194
1195                 snprintf(name, strlen(name), "0x%lx", ind_ino);
1196
1197                 hash = init_name_hash();
1198                 while (len--) {
1199                         unsigned char c;
1200                         c = *(const unsigned char *)name++;
1201                         if (c == '\0') break;
1202                         hash = partial_name_hash(c, hash);
1203                 }
1204                 dentry->d_name.hash = end_name_hash(hash);
1205         }
1206         RETURN(rc);
1207 }
1208
1209 struct inode *smfs_cow_get_ind(struct inode *inode, int index)
1210 {
1211         long block=(index << PAGE_CACHE_SHIFT) >> inode->i_sb->s_blocksize_bits;
1212         struct fsfilt_operations *sops = I2SNAPCOPS(inode);
1213         struct snap_info *snap_info = NULL;
1214         struct snap_table *table = NULL;
1215         int slot;
1216
1217         ENTRY;
1218
1219         snap_info = smfs_find_snap_info(inode);
1220         if (!snap_info) {
1221                 CDEBUG(D_INFO, "can not find snap info for inode %p\n", inode);
1222                 RETURN(NULL);
1223         }
1224
1225         table = snap_info->sni_table;
1226
1227         for (slot = table->sntbl_count - 1; slot >= 0; slot--) {
1228                 struct address_space_operations *aops = inode->i_mapping->a_ops;
1229                 struct inode *cache_inode = NULL;
1230                 int index = 0;
1231
1232                 index = table->sntbl_items[slot].sn_index;
1233                 cache_inode = sops->fs_get_indirect(I2CI(inode), NULL, index);
1234
1235                 if (!cache_inode )  continue;
1236
1237                 if (aops->bmap(cache_inode->i_mapping, block))
1238                        RETURN(cache_inode);
1239                 iput(cache_inode);
1240         }
1241
1242         RETURN(NULL);
1243 }
1244 EXPORT_SYMBOL(smfs_cow_get_ind);
1245
1246 typedef int (*cow_funcs)(struct inode *dir, struct dentry *dentry,
1247                          void *new_dir, void *new_dentry);
1248
1249 static cow_funcs smfs_cow_pre_funcs[HOOK_MAX + 1] = {
1250         [HOOK_CREATE]   smfs_cow_create,
1251         [HOOK_LOOKUP]   smfs_cow_lookup,
1252         [HOOK_LINK]     smfs_cow_link,
1253         [HOOK_UNLINK]   smfs_cow_unlink,
1254         [HOOK_SYMLINK]  smfs_cow_create,
1255         [HOOK_MKDIR]    smfs_cow_create,
1256         [HOOK_RMDIR]    smfs_cow_unlink,
1257         [HOOK_MKNOD]    smfs_cow_create,
1258         [HOOK_RENAME]   smfs_cow_rename,
1259         [HOOK_SETATTR]  smfs_cow_setattr,
1260         [HOOK_WRITE]    smfs_cow_write,
1261 };
1262 int smfs_cow_lookup_post(struct inode *dir, struct dentry *dentry, void *data1,
1263                          void *data2)
1264 {
1265         struct inode *inode = dentry->d_inode;
1266         struct fsfilt_operations *sops = I2SNAPCOPS(inode);
1267         int index = I2SNAPI(dir)->sn_index;
1268         ENTRY;
1269
1270         LASSERT(inode);
1271
1272         if (index > 0) {
1273                 struct inode *cache_ind = NULL;
1274
1275                 cache_ind = sops->fs_get_indirect(I2CI(inode), NULL, index);
1276                 if (cache_ind->i_ino != I2CI(inode)->i_ino) {
1277                         struct inode *ind_inode = NULL;
1278
1279                         ind_inode = smfs_get_inode(dir->i_sb, cache_ind->i_ino,
1280                                                    dir, index);
1281                         /*replace the ind_inode here*/
1282                         list_del_init(&dentry->d_alias);
1283                         iput(inode);
1284                         d_instantiate(dentry, ind_inode);
1285                 }
1286         }
1287         inode = dentry->d_inode;
1288
1289         smfs_init_snap_inode_info(inode, dir, index);
1290
1291         RETURN(0);
1292 }
1293
1294 static cow_funcs smfs_cow_post_funcs[HOOK_MAX + 1] = {
1295         [HOOK_CREATE]   NULL,
1296         [HOOK_LOOKUP]   smfs_cow_lookup_post,
1297         [HOOK_LINK]     NULL,
1298         [HOOK_UNLINK]   NULL,
1299         [HOOK_SYMLINK]  NULL,
1300         [HOOK_MKDIR]    NULL,
1301         [HOOK_RMDIR]    NULL,
1302         [HOOK_MKNOD]    NULL,
1303         [HOOK_RENAME]   NULL,
1304         [HOOK_SETATTR]  NULL,
1305         [HOOK_WRITE]    NULL,
1306 };
1307
1308 static int smfs_cow_pre(struct inode *dir, struct dentry *dentry, void *new_dir,
1309                         void *new_dentry, int op)
1310 {
1311         if (smfs_cow_pre_funcs[op]) {
1312                 return smfs_cow_pre_funcs[op](dir, dentry, new_dir, new_dentry);
1313         }
1314         return 0;
1315 }
1316
1317 static int smfs_cow_post(struct inode *dir, struct dentry *dentry, void *new_dir,
1318                          void *new_dentry, int op)
1319 {
1320         if (smfs_cow_post_funcs[op]) {
1321                 return smfs_cow_post_funcs[op](dir, dentry, new_dir, new_dentry);
1322         }
1323         return 0;
1324 }
1325