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   1 /* -*- mode: c; c-basic-offset: 8; -*-
   2  * vim: noexpandtab sw=8 ts=8 sts=0:
   3  *
   4  * extent_map.c
   5  *
   6  * Block/Cluster mapping functions
   7  *
   8  * Copyright (C) 2004 Oracle.  All rights reserved.
   9  *
  10  * This program is free software; you can redistribute it and/or
  11  * modify it under the terms of the GNU General Public
  12  * License, version 2,  as published by the Free Software Foundation.
  13  *
  14  * This program is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  17  * General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU General Public
  20  * License along with this program; if not, write to the
  21  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  22  * Boston, MA 021110-1307, USA.
  23  */
  24
  25 #include <linux/fs.h>
  26 #include <linux/init.h>
  27 #include <linux/types.h>
  28 #include <linux/fiemap.h>
  29
  30 #define MLOG_MASK_PREFIX ML_EXTENT_MAP
  31 #include <cluster/masklog.h>
  32
  33 #include "ocfs2.h"
  34
  35 #include "alloc.h"
  36 #include "dlmglue.h"
  37 #include "extent_map.h"
  38 #include "inode.h"
  39 #include "super.h"
  40
  41 #include "buffer_head_io.h"
  42
  43 /*
  44  * The extent caching implementation is intentionally trivial.
  45  *
  46  * We only cache a small number of extents stored directly on the
  47  * inode, so linear order operations are acceptable. If we ever want
  48  * to increase the size of the extent map, then these algorithms must
  49  * get smarter.
  50  */
  51
  52 void ocfs2_extent_map_init(struct inode *inode)
  53 {
  54         struct ocfs2_inode_info *oi = OCFS2_I(inode);
  55
  56         oi->ip_extent_map.em_num_items = 0;
  57         INIT_LIST_HEAD(&oi->ip_extent_map.em_list);
  58 }
  59
  60 static void __ocfs2_extent_map_lookup(struct ocfs2_extent_map *em,
  61                                       unsigned int cpos,
  62                                       struct ocfs2_extent_map_item **ret_emi)
  63 {
  64         unsigned int range;
  65         struct ocfs2_extent_map_item *emi;
  66
  67         *ret_emi = NULL;
  68
  69         list_for_each_entry(emi, &em->em_list, ei_list) {
  70                 range = emi->ei_cpos + emi->ei_clusters;
  71
  72                 if (cpos >= emi->ei_cpos && cpos < range) {
  73                         list_move(&emi->ei_list, &em->em_list);
  74
  75                         *ret_emi = emi;
  76                         break;
  77                 }
  78         }
  79 }
  80
  81 static int ocfs2_extent_map_lookup(struct inode *inode, unsigned int cpos,
  82                                    unsigned int *phys, unsigned int *len,
  83                                    unsigned int *flags)
  84 {
  85         unsigned int coff;
  86         struct ocfs2_inode_info *oi = OCFS2_I(inode);
  87         struct ocfs2_extent_map_item *emi;
  88
  89         spin_lock(&oi->ip_lock);
  90
  91         __ocfs2_extent_map_lookup(&oi->ip_extent_map, cpos, &emi);
  92         if (emi) {
  93                 coff = cpos - emi->ei_cpos;
  94                 *phys = emi->ei_phys + coff;
  95                 if (len)
  96                         *len = emi->ei_clusters - coff;
  97                 if (flags)
  98                         *flags = emi->ei_flags;
  99         }
 100
 101         spin_unlock(&oi->ip_lock);
 102
 103         if (emi == NULL)
 104                 return -ENOENT;
 105
 106         return 0;
 107 }
 108
 109 /*
 110  * Forget about all clusters equal to or greater than cpos.
 111  */
 112 void ocfs2_extent_map_trunc(struct inode *inode, unsigned int cpos)
 113 {
 114         struct ocfs2_extent_map_item *emi, *n;
 115         struct ocfs2_inode_info *oi = OCFS2_I(inode);
 116         struct ocfs2_extent_map *em = &oi->ip_extent_map;
 117         LIST_HEAD(tmp_list);
 118         unsigned int range;
 119
 120         spin_lock(&oi->ip_lock);
 121         list_for_each_entry_safe(emi, n, &em->em_list, ei_list) {
 122                 if (emi->ei_cpos >= cpos) {
 123                         /* Full truncate of this record. */
 124                         list_move(&emi->ei_list, &tmp_list);
 125                         BUG_ON(em->em_num_items == 0);
 126                         em->em_num_items--;
 127                         continue;
 128                 }
 129
 130                 range = emi->ei_cpos + emi->ei_clusters;
 131                 if (range > cpos) {
 132                         /* Partial truncate */
 133                         emi->ei_clusters = cpos - emi->ei_cpos;
 134                 }
 135         }
 136         spin_unlock(&oi->ip_lock);
 137
 138         list_for_each_entry_safe(emi, n, &tmp_list, ei_list) {
 139                 list_del(&emi->ei_list);
 140                 kfree(emi);
 141         }
 142 }
 143
 144 /*
 145  * Is any part of emi2 contained within emi1
 146  */
 147 static int ocfs2_ei_is_contained(struct ocfs2_extent_map_item *emi1,
 148                                  struct ocfs2_extent_map_item *emi2)
 149 {
 150         unsigned int range1, range2;
 151
 152         /*
 153          * Check if logical start of emi2 is inside emi1
 154          */
 155         range1 = emi1->ei_cpos + emi1->ei_clusters;
 156         if (emi2->ei_cpos >= emi1->ei_cpos && emi2->ei_cpos < range1)
 157                 return 1;
 158
 159         /*
 160          * Check if logical end of emi2 is inside emi1
 161          */
 162         range2 = emi2->ei_cpos + emi2->ei_clusters;
 163         if (range2 > emi1->ei_cpos && range2 <= range1)
 164                 return 1;
 165
 166         return 0;
 167 }
 168
 169 static void ocfs2_copy_emi_fields(struct ocfs2_extent_map_item *dest,
 170                                   struct ocfs2_extent_map_item *src)
 171 {
 172         dest->ei_cpos = src->ei_cpos;
 173         dest->ei_phys = src->ei_phys;
 174         dest->ei_clusters = src->ei_clusters;
 175         dest->ei_flags = src->ei_flags;
 176 }
 177
 178 /*
 179  * Try to merge emi with ins. Returns 1 if merge succeeds, zero
 180  * otherwise.
 181  */
 182 static int ocfs2_try_to_merge_extent_map(struct ocfs2_extent_map_item *emi,
 183                                          struct ocfs2_extent_map_item *ins)
 184 {
 185         /*
 186          * Handle contiguousness
 187          */
 188         if (ins->ei_phys == (emi->ei_phys + emi->ei_clusters) &&
 189             ins->ei_cpos == (emi->ei_cpos + emi->ei_clusters) &&
 190             ins->ei_flags == emi->ei_flags) {
 191                 emi->ei_clusters += ins->ei_clusters;
 192                 return 1;
 193         } else if ((ins->ei_phys + ins->ei_clusters) == emi->ei_phys &&
 194                    (ins->ei_cpos + ins->ei_clusters) == emi->ei_phys &&
 195                    ins->ei_flags == emi->ei_flags) {
 196                 emi->ei_phys = ins->ei_phys;
 197                 emi->ei_cpos = ins->ei_cpos;
 198                 emi->ei_clusters += ins->ei_clusters;
 199                 return 1;
 200         }
 201
 202         /*
 203          * Overlapping extents - this shouldn't happen unless we've
 204          * split an extent to change it's flags. That is exceedingly
 205          * rare, so there's no sense in trying to optimize it yet.
 206          */
 207         if (ocfs2_ei_is_contained(emi, ins) ||
 208             ocfs2_ei_is_contained(ins, emi)) {
 209                 ocfs2_copy_emi_fields(emi, ins);
 210                 return 1;
 211         }
 212
 213         /* No merge was possible. */
 214         return 0;
 215 }
 216
 217 /*
 218  * In order to reduce complexity on the caller, this insert function
 219  * is intentionally liberal in what it will accept.
 220  *
 221  * The only rule is that the truncate call *must* be used whenever
 222  * records have been deleted. This avoids inserting overlapping
 223  * records with different physical mappings.
 224  */
 225 void ocfs2_extent_map_insert_rec(struct inode *inode,
 226                                  struct ocfs2_extent_rec *rec)
 227 {
 228         struct ocfs2_inode_info *oi = OCFS2_I(inode);
 229         struct ocfs2_extent_map *em = &oi->ip_extent_map;
 230         struct ocfs2_extent_map_item *emi, *new_emi = NULL;
 231         struct ocfs2_extent_map_item ins;
 232
 233         ins.ei_cpos = le32_to_cpu(rec->e_cpos);
 234         ins.ei_phys = ocfs2_blocks_to_clusters(inode->i_sb,
 235                                                le64_to_cpu(rec->e_blkno));
 236         ins.ei_clusters = le16_to_cpu(rec->e_leaf_clusters);
 237         ins.ei_flags = rec->e_flags;
 238
 239 search:
 240         spin_lock(&oi->ip_lock);
 241
 242         list_for_each_entry(emi, &em->em_list, ei_list) {
 243                 if (ocfs2_try_to_merge_extent_map(emi, &ins)) {
 244                         list_move(&emi->ei_list, &em->em_list);
 245                         spin_unlock(&oi->ip_lock);
 246                         goto out;
 247                 }
 248         }
 249
 250         /*
 251          * No item could be merged.
 252          *
 253          * Either allocate and add a new item, or overwrite the last recently
 254          * inserted.
 255          */
 256
 257         if (em->em_num_items < OCFS2_MAX_EXTENT_MAP_ITEMS) {
 258                 if (new_emi == NULL) {
 259                         spin_unlock(&oi->ip_lock);
 260
 261                         new_emi = kmalloc(sizeof(*new_emi), GFP_NOFS);
 262                         if (new_emi == NULL)
 263                                 goto out;
 264
 265                         goto search;
 266                 }
 267
 268                 ocfs2_copy_emi_fields(new_emi, &ins);
 269                 list_add(&new_emi->ei_list, &em->em_list);
 270                 em->em_num_items++;
 271                 new_emi = NULL;
 272         } else {
 273                 BUG_ON(list_empty(&em->em_list) || em->em_num_items == 0);
 274                 emi = list_entry(em->em_list.prev,
 275                                  struct ocfs2_extent_map_item, ei_list);
 276                 list_move(&emi->ei_list, &em->em_list);
 277                 ocfs2_copy_emi_fields(emi, &ins);
 278         }
 279
 280         spin_unlock(&oi->ip_lock);
 281
 282 out:
 283         if (new_emi)
 284                 kfree(new_emi);
 285 }
 286
 287 static int ocfs2_last_eb_is_empty(struct inode *inode,
 288                                   struct ocfs2_dinode *di)
 289 {
 290         int ret, next_free;
 291         u64 last_eb_blk = le64_to_cpu(di->i_last_eb_blk);
 292         struct buffer_head *eb_bh = NULL;
 293         struct ocfs2_extent_block *eb;
 294         struct ocfs2_extent_list *el;
 295
 296         ret = ocfs2_read_block(OCFS2_SB(inode->i_sb), last_eb_blk,
 297                                &eb_bh, OCFS2_BH_CACHED, inode);
 298         if (ret) {
 299                 mlog_errno(ret);
 300                 goto out;
 301         }
 302
 303         eb = (struct ocfs2_extent_block *) eb_bh->b_data;
 304         el = &eb->h_list;
 305
 306         if (!OCFS2_IS_VALID_EXTENT_BLOCK(eb)) {
 307                 ret = -EROFS;
 308                 OCFS2_RO_ON_INVALID_EXTENT_BLOCK(inode->i_sb, eb);
 309                 goto out;
 310         }
 311
 312         if (el->l_tree_depth) {
 313                 ocfs2_error(inode->i_sb,
 314                             "Inode %lu has non zero tree depth in "
 315                             "leaf block %llu\n", inode->i_ino,
 316                             (unsigned long long)eb_bh->b_blocknr);
 317                 ret = -EROFS;
 318                 goto out;
 319         }
 320
 321         next_free = le16_to_cpu(el->l_next_free_rec);
 322
 323         if (next_free == 0 ||
 324             (next_free == 1 && ocfs2_is_empty_extent(&el->l_recs[0])))
 325                 ret = 1;
 326
 327 out:
 328         brelse(eb_bh);
 329         return ret;
 330 }
 331
 332 /*
 333  * Return the 1st index within el which contains an extent start
 334  * larger than v_cluster.
 335  */
 336 static int ocfs2_search_for_hole_index(struct ocfs2_extent_list *el,
 337                                        u32 v_cluster)
 338 {
 339         int i;
 340         struct ocfs2_extent_rec *rec;
 341
 342         for(i = 0; i < le16_to_cpu(el->l_next_free_rec); i++) {
 343                 rec = &el->l_recs[i];
 344
 345                 if (v_cluster < le32_to_cpu(rec->e_cpos))
 346                         break;
 347         }
 348
 349         return i;
 350 }
 351
 352 /*
 353  * Figure out the size of a hole which starts at v_cluster within the given
 354  * extent list.
 355  *
 356  * If there is no more allocation past v_cluster, we return the maximum
 357  * cluster size minus v_cluster.
 358  *
 359  * If we have in-inode extents, then el points to the dinode list and
 360  * eb_bh is NULL. Otherwise, eb_bh should point to the extent block
 361  * containing el.
 362  */
 363 static int ocfs2_figure_hole_clusters(struct inode *inode,
 364                                       struct ocfs2_extent_list *el,
 365                                       struct buffer_head *eb_bh,
 366                                       u32 v_cluster,
 367                                       u32 *num_clusters)
 368 {
 369         int ret, i;
 370         struct buffer_head *next_eb_bh = NULL;
 371         struct ocfs2_extent_block *eb, *next_eb;
 372
 373         i = ocfs2_search_for_hole_index(el, v_cluster);
 374
 375         if (i == le16_to_cpu(el->l_next_free_rec) && eb_bh) {
 376                 eb = (struct ocfs2_extent_block *)eb_bh->b_data;
 377
 378                 /*
 379                  * Check the next leaf for any extents.
 380                  */
 381
 382                 if (le64_to_cpu(eb->h_next_leaf_blk) == 0ULL)
 383                         goto no_more_extents;
 384
 385                 ret = ocfs2_read_block(OCFS2_SB(inode->i_sb),
 386                                        le64_to_cpu(eb->h_next_leaf_blk),
 387                                        &next_eb_bh, OCFS2_BH_CACHED, inode);
 388                 if (ret) {
 389                         mlog_errno(ret);
 390                         goto out;
 391                 }
 392                 next_eb = (struct ocfs2_extent_block *)next_eb_bh->b_data;
 393
 394                 if (!OCFS2_IS_VALID_EXTENT_BLOCK(next_eb)) {
 395                         ret = -EROFS;
 396                         OCFS2_RO_ON_INVALID_EXTENT_BLOCK(inode->i_sb, next_eb);
 397                         goto out;
 398                 }
 399
 400                 el = &next_eb->h_list;
 401
 402                 i = ocfs2_search_for_hole_index(el, v_cluster);
 403         }
 404
 405 no_more_extents:
 406         if (i == le16_to_cpu(el->l_next_free_rec)) {
 407                 /*
 408                  * We're at the end of our existing allocation. Just
 409                  * return the maximum number of clusters we could
 410                  * possibly allocate.
 411                  */
 412                 *num_clusters = UINT_MAX - v_cluster;
 413         } else {
 414                 *num_clusters = le32_to_cpu(el->l_recs[i].e_cpos) - v_cluster;
 415         }
 416
 417         ret = 0;
 418 out:
 419         brelse(next_eb_bh);
 420         return ret;
 421 }
 422
 423 static int ocfs2_get_clusters_nocache(struct inode *inode,
 424                                       struct buffer_head *di_bh,
 425                                       u32 v_cluster, unsigned int *hole_len,
 426                                       struct ocfs2_extent_rec *ret_rec,
 427                                       unsigned int *is_last)
 428 {
 429         int i, ret, tree_height, len;
 430         struct ocfs2_dinode *di;
 431         struct ocfs2_extent_block *uninitialized_var(eb);
 432         struct ocfs2_extent_list *el;
 433         struct ocfs2_extent_rec *rec;
 434         struct buffer_head *eb_bh = NULL;
 435
 436         memset(ret_rec, 0, sizeof(*ret_rec));
 437         if (is_last)
 438                 *is_last = 0;
 439
 440         di = (struct ocfs2_dinode *) di_bh->b_data;
 441         el = &di->id2.i_list;
 442         tree_height = le16_to_cpu(el->l_tree_depth);
 443
 444         if (tree_height > 0) {
 445                 ret = ocfs2_find_leaf(inode, el, v_cluster, &eb_bh);
 446                 if (ret) {
 447                         mlog_errno(ret);
 448                         goto out;
 449                 }
 450
 451                 eb = (struct ocfs2_extent_block *) eb_bh->b_data;
 452                 el = &eb->h_list;
 453
 454                 if (el->l_tree_depth) {
 455                         ocfs2_error(inode->i_sb,
 456                                     "Inode %lu has non zero tree depth in "
 457                                     "leaf block %llu\n", inode->i_ino,
 458                                     (unsigned long long)eb_bh->b_blocknr);
 459                         ret = -EROFS;
 460                         goto out;
 461                 }
 462         }
 463
 464         i = ocfs2_search_extent_list(el, v_cluster);
 465         if (i == -1) {
 466                 /*
 467                  * Holes can be larger than the maximum size of an
 468                  * extent, so we return their lengths in a seperate
 469                  * field.
 470                  */
 471                 if (hole_len) {
 472                         ret = ocfs2_figure_hole_clusters(inode, el, eb_bh,
 473                                                          v_cluster, &len);
 474                         if (ret) {
 475                                 mlog_errno(ret);
 476                                 goto out;
 477                         }
 478
 479                         *hole_len = len;
 480                 }
 481                 goto out_hole;
 482         }
 483
 484         rec = &el->l_recs[i];
 485
 486         BUG_ON(v_cluster < le32_to_cpu(rec->e_cpos));
 487
 488         if (!rec->e_blkno) {
 489                 ocfs2_error(inode->i_sb, "Inode %lu has bad extent "
 490                             "record (%u, %u, 0)", inode->i_ino,
 491                             le32_to_cpu(rec->e_cpos),
 492                             ocfs2_rec_clusters(el, rec));
 493                 ret = -EROFS;
 494                 goto out;
 495         }
 496
 497         *ret_rec = *rec;
 498
 499         /*
 500          * Checking for last extent is potentially expensive - we
 501          * might have to look at the next leaf over to see if it's
 502          * empty.
 503          *
 504          * The first two checks are to see whether the caller even
 505          * cares for this information, and if the extent is at least
 506          * the last in it's list.
 507          *
 508          * If those hold true, then the extent is last if any of the
 509          * additional conditions hold true:
 510          *  - Extent list is in-inode
 511          *  - Extent list is right-most
 512          *  - Extent list is 2nd to rightmost, with empty right-most
 513          */
 514         if (is_last) {
 515                 if (i == (le16_to_cpu(el->l_next_free_rec) - 1)) {
 516                         if (tree_height == 0)
 517                                 *is_last = 1;
 518                         else if (eb->h_blkno == di->i_last_eb_blk)
 519                                 *is_last = 1;
 520                         else if (eb->h_next_leaf_blk == di->i_last_eb_blk) {
 521                                 ret = ocfs2_last_eb_is_empty(inode, di);
 522                                 if (ret < 0) {
 523                                         mlog_errno(ret);
 524                                         goto out;
 525                                 }
 526                                 if (ret == 1)
 527                                         *is_last = 1;
 528                         }
 529                 }
 530         }
 531
 532 out_hole:
 533         ret = 0;
 534 out:
 535         brelse(eb_bh);
 536         return ret;
 537 }
 538
 539 static void ocfs2_relative_extent_offsets(struct super_block *sb,
 540                                           u32 v_cluster,
 541                                           struct ocfs2_extent_rec *rec,
 542                                           u32 *p_cluster, u32 *num_clusters)
 543
 544 {
 545         u32 coff = v_cluster - le32_to_cpu(rec->e_cpos);
 546
 547         *p_cluster = ocfs2_blocks_to_clusters(sb, le64_to_cpu(rec->e_blkno));
 548         *p_cluster = *p_cluster + coff;
 549
 550         if (num_clusters)
 551                 *num_clusters = le16_to_cpu(rec->e_leaf_clusters) - coff;
 552 }
 553
 554 int ocfs2_get_clusters(struct inode *inode, u32 v_cluster,
 555                        u32 *p_cluster, u32 *num_clusters,
 556                        unsigned int *extent_flags)
 557 {
 558         int ret;
 559         unsigned int uninitialized_var(hole_len), flags = 0;
 560         struct buffer_head *di_bh = NULL;
 561         struct ocfs2_extent_rec rec;
 562
 563         if (OCFS2_I(inode)->ip_dyn_features & OCFS2_INLINE_DATA_FL) {
 564                 ret = -ERANGE;
 565                 mlog_errno(ret);
 566                 goto out;
 567         }
 568
 569         ret = ocfs2_extent_map_lookup(inode, v_cluster, p_cluster,
 570                                       num_clusters, extent_flags);
 571         if (ret == 0)
 572                 goto out;
 573
 574         ret = ocfs2_read_block(OCFS2_SB(inode->i_sb), OCFS2_I(inode)->ip_blkno,
 575                                &di_bh, OCFS2_BH_CACHED, inode);
 576         if (ret) {
 577                 mlog_errno(ret);
 578                 goto out;
 579         }
 580
 581         ret = ocfs2_get_clusters_nocache(inode, di_bh, v_cluster, &hole_len,
 582                                          &rec, NULL);
 583         if (ret) {
 584                 mlog_errno(ret);
 585                 goto out;
 586         }
 587
 588         if (rec.e_blkno == 0ULL) {
 589                 /*
 590                  * A hole was found. Return some canned values that
 591                  * callers can key on. If asked for, num_clusters will
 592                  * be populated with the size of the hole.
 593                  */
 594                 *p_cluster = 0;
 595                 if (num_clusters) {
 596                         *num_clusters = hole_len;
 597                 }
 598         } else {
 599                 ocfs2_relative_extent_offsets(inode->i_sb, v_cluster, &rec,
 600                                               p_cluster, num_clusters);
 601                 flags = rec.e_flags;
 602
 603                 ocfs2_extent_map_insert_rec(inode, &rec);
 604         }
 605
 606         if (extent_flags)
 607                 *extent_flags = flags;
 608
 609 out:
 610         brelse(di_bh);
 611         return ret;
 612 }
 613
 614 /*
 615  * This expects alloc_sem to be held. The allocation cannot change at
 616  * all while the map is in the process of being updated.
 617  */
 618 int ocfs2_extent_map_get_blocks(struct inode *inode, u64 v_blkno, u64 *p_blkno,
 619                                 u64 *ret_count, unsigned int *extent_flags)
 620 {
 621         int ret;
 622         int bpc = ocfs2_clusters_to_blocks(inode->i_sb, 1);
 623         u32 cpos, num_clusters, p_cluster;
 624         u64 boff = 0;
 625
 626         cpos = ocfs2_blocks_to_clusters(inode->i_sb, v_blkno);
 627
 628         ret = ocfs2_get_clusters(inode, cpos, &p_cluster, &num_clusters,
 629                                  extent_flags);
 630         if (ret) {
 631                 mlog_errno(ret);
 632                 goto out;
 633         }
 634
 635         /*
 636          * p_cluster == 0 indicates a hole.
 637          */
 638         if (p_cluster) {
 639                 boff = ocfs2_clusters_to_blocks(inode->i_sb, p_cluster);
 640                 boff += (v_blkno & (u64)(bpc - 1));
 641         }
 642
 643         *p_blkno = boff;
 644
 645         if (ret_count) {
 646                 *ret_count = ocfs2_clusters_to_blocks(inode->i_sb, num_clusters);
 647                 *ret_count -= v_blkno & (u64)(bpc - 1);
 648         }
 649
 650 out:
 651         return ret;
 652 }
 653
 654 static int ocfs2_fiemap_inline(struct inode *inode, struct buffer_head *di_bh,
 655                                struct fiemap_extent_info *fieinfo,
 656                                u64 map_start)
 657 {
 658         int ret;
 659         unsigned int id_count;
 660         struct ocfs2_dinode *di;
 661         u64 phys;
 662         u32 flags = FIEMAP_EXTENT_DATA_INLINE|FIEMAP_EXTENT_LAST;
 663         struct ocfs2_inode_info *oi = OCFS2_I(inode);
 664
 665         di = (struct ocfs2_dinode *)di_bh->b_data;
 666         id_count = le16_to_cpu(di->id2.i_data.id_count);
 667
 668         if (map_start < id_count) {
 669                 phys = oi->ip_blkno << inode->i_sb->s_blocksize_bits;
 670                 phys += offsetof(struct ocfs2_dinode, id2.i_data.id_data);
 671
 672                 ret = fiemap_fill_next_extent(fieinfo, 0, phys, id_count,
 673                                               flags);
 674                 if (ret < 0)
 675                         return ret;
 676         }
 677
 678         return 0;
 679 }
 680
 681 #define OCFS2_FIEMAP_FLAGS      (FIEMAP_FLAG_SYNC)
 682
 683 int ocfs2_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
 684                  u64 map_start, u64 map_len)
 685 {
 686         int ret, is_last;
 687         u32 mapping_end, cpos;
 688         unsigned int hole_size;
 689         struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
 690         u64 len_bytes, phys_bytes, virt_bytes;
 691         struct buffer_head *di_bh = NULL;
 692         struct ocfs2_extent_rec rec;
 693
 694         ret = fiemap_check_flags(fieinfo, OCFS2_FIEMAP_FLAGS);
 695         if (ret)
 696                 return ret;
 697
 698         ret = ocfs2_inode_lock(inode, &di_bh, 0);
 699         if (ret) {
 700                 mlog_errno(ret);
 701                 goto out;
 702         }
 703
 704         down_read(&OCFS2_I(inode)->ip_alloc_sem);
 705
 706         /*
 707          * Handle inline-data separately.
 708          */
 709         if (OCFS2_I(inode)->ip_dyn_features & OCFS2_INLINE_DATA_FL) {
 710                 ret = ocfs2_fiemap_inline(inode, di_bh, fieinfo, map_start);
 711                 goto out_unlock;
 712         }
 713
 714         cpos = map_start >> osb->s_clustersize_bits;
 715         mapping_end = ocfs2_clusters_for_bytes(inode->i_sb,
 716                                                map_start + map_len);
 717         mapping_end -= cpos;
 718         is_last = 0;
 719         while (cpos < mapping_end && !is_last) {
 720                 u32 fe_flags;
 721
 722                 ret = ocfs2_get_clusters_nocache(inode, di_bh, cpos,
 723                                                  &hole_size, &rec, &is_last);
 724                 if (ret) {
 725                         mlog_errno(ret);
 726                         goto out;
 727                 }
 728
 729                 if (rec.e_blkno == 0ULL) {
 730                         cpos += hole_size;
 731                         continue;
 732                 }
 733
 734                 fe_flags = 0;
 735                 if (rec.e_flags & OCFS2_EXT_UNWRITTEN)
 736                         fe_flags |= FIEMAP_EXTENT_UNWRITTEN;
 737                 if (is_last)
 738                         fe_flags |= FIEMAP_EXTENT_LAST;
 739                 len_bytes = (u64)le16_to_cpu(rec.e_leaf_clusters) << osb->s_clustersize_bits;
 740                 phys_bytes = le64_to_cpu(rec.e_blkno) << osb->sb->s_blocksize_bits;
 741                 virt_bytes = (u64)le32_to_cpu(rec.e_cpos) << osb->s_clustersize_bits;
 742
 743                 ret = fiemap_fill_next_extent(fieinfo, virt_bytes, phys_bytes,
 744                                               len_bytes, fe_flags);
 745                 if (ret)
 746                         break;
 747
 748                 cpos = le32_to_cpu(rec.e_cpos)+ le16_to_cpu(rec.e_leaf_clusters);
 749         }
 750
 751         if (ret > 0)
 752                 ret = 0;
 753
 754 out_unlock:
 755         brelse(di_bh);
 756
 757         up_read(&OCFS2_I(inode)->ip_alloc_sem);
 758
 759         ocfs2_inode_unlock(inode, 0);
 760 out:
 761
 762         return ret;
 763 }