fs/ocfs2/extent_map.c

   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/slab.h>
  28 #include <linux/types.h>
  29 #include <linux/fiemap.h>
  30
  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 #include "symlink.h"
  41 #include "aops.h"
  42 #include "ocfs2_trace.h"
  43
  44 #include "buffer_head_io.h"
  45
  46 /*
  47  * The extent caching implementation is intentionally trivial.
  48  *
  49  * We only cache a small number of extents stored directly on the
  50  * inode, so linear order operations are acceptable. If we ever want
  51  * to increase the size of the extent map, then these algorithms must
  52  * get smarter.
  53  */
  54
  55 void ocfs2_extent_map_init(struct inode *inode)
  56 {
  57         struct ocfs2_inode_info *oi = OCFS2_I(inode);
  58
  59         oi->ip_extent_map.em_num_items = 0;
  60         INIT_LIST_HEAD(&oi->ip_extent_map.em_list);
  61 }
  62
  63 static void __ocfs2_extent_map_lookup(struct ocfs2_extent_map *em,
  64                                       unsigned int cpos,
  65                                       struct ocfs2_extent_map_item **ret_emi)
  66 {
  67         unsigned int range;
  68         struct ocfs2_extent_map_item *emi;
  69
  70         *ret_emi = NULL;
  71
  72         list_for_each_entry(emi, &em->em_list, ei_list) {
  73                 range = emi->ei_cpos + emi->ei_clusters;
  74
  75                 if (cpos >= emi->ei_cpos && cpos < range) {
  76                         list_move(&emi->ei_list, &em->em_list);
  77
  78                         *ret_emi = emi;
  79                         break;
  80                 }
  81         }
  82 }
  83
  84 static int ocfs2_extent_map_lookup(struct inode *inode, unsigned int cpos,
  85                                    unsigned int *phys, unsigned int *len,
  86                                    unsigned int *flags)
  87 {
  88         unsigned int coff;
  89         struct ocfs2_inode_info *oi = OCFS2_I(inode);
  90         struct ocfs2_extent_map_item *emi;
  91
  92         spin_lock(&oi->ip_lock);
  93
  94         __ocfs2_extent_map_lookup(&oi->ip_extent_map, cpos, &emi);
  95         if (emi) {
  96                 coff = cpos - emi->ei_cpos;
  97                 *phys = emi->ei_phys + coff;
  98                 if (len)
  99                         *len = emi->ei_clusters - coff;
 100                 if (flags)
 101                         *flags = emi->ei_flags;
 102         }
 103
 104         spin_unlock(&oi->ip_lock);
 105
 106         if (emi == NULL)
 107                 return -ENOENT;
 108
 109         return 0;
 110 }
 111
 112 /*
 113  * Forget about all clusters equal to or greater than cpos.
 114  */
 115 void ocfs2_extent_map_trunc(struct inode *inode, unsigned int cpos)
 116 {
 117         struct ocfs2_extent_map_item *emi, *n;
 118         struct ocfs2_inode_info *oi = OCFS2_I(inode);
 119         struct ocfs2_extent_map *em = &oi->ip_extent_map;
 120         LIST_HEAD(tmp_list);
 121         unsigned int range;
 122
 123         spin_lock(&oi->ip_lock);
 124         list_for_each_entry_safe(emi, n, &em->em_list, ei_list) {
 125                 if (emi->ei_cpos >= cpos) {
 126                         /* Full truncate of this record. */
 127                         list_move(&emi->ei_list, &tmp_list);
 128                         BUG_ON(em->em_num_items == 0);
 129                         em->em_num_items--;
 130                         continue;
 131                 }
 132
 133                 range = emi->ei_cpos + emi->ei_clusters;
 134                 if (range > cpos) {
 135                         /* Partial truncate */
 136                         emi->ei_clusters = cpos - emi->ei_cpos;
 137                 }
 138         }
 139         spin_unlock(&oi->ip_lock);
 140
 141         list_for_each_entry_safe(emi, n, &tmp_list, ei_list) {
 142                 list_del(&emi->ei_list);
 143                 kfree(emi);
 144         }
 145 }
 146
 147 /*
 148  * Is any part of emi2 contained within emi1
 149  */
 150 static int ocfs2_ei_is_contained(struct ocfs2_extent_map_item *emi1,
 151                                  struct ocfs2_extent_map_item *emi2)
 152 {
 153         unsigned int range1, range2;
 154
 155         /*
 156          * Check if logical start of emi2 is inside emi1
 157          */
 158         range1 = emi1->ei_cpos + emi1->ei_clusters;
 159         if (emi2->ei_cpos >= emi1->ei_cpos && emi2->ei_cpos < range1)
 160                 return 1;
 161
 162         /*
 163          * Check if logical end of emi2 is inside emi1
 164          */
 165         range2 = emi2->ei_cpos + emi2->ei_clusters;
 166         if (range2 > emi1->ei_cpos && range2 <= range1)
 167                 return 1;
 168
 169         return 0;
 170 }
 171
 172 static void ocfs2_copy_emi_fields(struct ocfs2_extent_map_item *dest,
 173                                   struct ocfs2_extent_map_item *src)
 174 {
 175         dest->ei_cpos = src->ei_cpos;
 176         dest->ei_phys = src->ei_phys;
 177         dest->ei_clusters = src->ei_clusters;
 178         dest->ei_flags = src->ei_flags;
 179 }
 180
 181 /*
 182  * Try to merge emi with ins. Returns 1 if merge succeeds, zero
 183  * otherwise.
 184  */
 185 static int ocfs2_try_to_merge_extent_map(struct ocfs2_extent_map_item *emi,
 186                                          struct ocfs2_extent_map_item *ins)
 187 {
 188         /*
 189          * Handle contiguousness
 190          */
 191         if (ins->ei_phys == (emi->ei_phys + emi->ei_clusters) &&
 192             ins->ei_cpos == (emi->ei_cpos + emi->ei_clusters) &&
 193             ins->ei_flags == emi->ei_flags) {
 194                 emi->ei_clusters += ins->ei_clusters;
 195                 return 1;
 196         } else if ((ins->ei_phys + ins->ei_clusters) == emi->ei_phys &&
 197                    (ins->ei_cpos + ins->ei_clusters) == emi->ei_cpos &&
 198                    ins->ei_flags == emi->ei_flags) {
 199                 emi->ei_phys = ins->ei_phys;
 200                 emi->ei_cpos = ins->ei_cpos;
 201                 emi->ei_clusters += ins->ei_clusters;
 202                 return 1;
 203         }
 204
 205         /*
 206          * Overlapping extents - this shouldn't happen unless we've
 207          * split an extent to change it's flags. That is exceedingly
 208          * rare, so there's no sense in trying to optimize it yet.
 209          */
 210         if (ocfs2_ei_is_contained(emi, ins) ||
 211             ocfs2_ei_is_contained(ins, emi)) {
 212                 ocfs2_copy_emi_fields(emi, ins);
 213                 return 1;
 214         }
 215
 216         /* No merge was possible. */
 217         return 0;
 218 }
 219
 220 /*
 221  * In order to reduce complexity on the caller, this insert function
 222  * is intentionally liberal in what it will accept.
 223  *
 224  * The only rule is that the truncate call *must* be used whenever
 225  * records have been deleted. This avoids inserting overlapping
 226  * records with different physical mappings.
 227  */
 228 void ocfs2_extent_map_insert_rec(struct inode *inode,
 229                                  struct ocfs2_extent_rec *rec)
 230 {
 231         struct ocfs2_inode_info *oi = OCFS2_I(inode);
 232         struct ocfs2_extent_map *em = &oi->ip_extent_map;
 233         struct ocfs2_extent_map_item *emi, *new_emi = NULL;
 234         struct ocfs2_extent_map_item ins;
 235
 236         ins.ei_cpos = le32_to_cpu(rec->e_cpos);
 237         ins.ei_phys = ocfs2_blocks_to_clusters(inode->i_sb,
 238                                                le64_to_cpu(rec->e_blkno));
 239         ins.ei_clusters = le16_to_cpu(rec->e_leaf_clusters);
 240         ins.ei_flags = rec->e_flags;
 241
 242 search:
 243         spin_lock(&oi->ip_lock);
 244
 245         list_for_each_entry(emi, &em->em_list, ei_list) {
 246                 if (ocfs2_try_to_merge_extent_map(emi, &ins)) {
 247                         list_move(&emi->ei_list, &em->em_list);
 248                         spin_unlock(&oi->ip_lock);
 249                         goto out;
 250                 }
 251         }
 252
 253         /*
 254          * No item could be merged.
 255          *
 256          * Either allocate and add a new item, or overwrite the last recently
 257          * inserted.
 258          */
 259
 260         if (em->em_num_items < OCFS2_MAX_EXTENT_MAP_ITEMS) {
 261                 if (new_emi == NULL) {
 262                         spin_unlock(&oi->ip_lock);
 263
 264                         new_emi = kmalloc(sizeof(*new_emi), GFP_NOFS);
 265                         if (new_emi == NULL)
 266                                 goto out;
 267
 268                         goto search;
 269                 }
 270
 271                 ocfs2_copy_emi_fields(new_emi, &ins);
 272                 list_add(&new_emi->ei_list, &em->em_list);
 273                 em->em_num_items++;
 274                 new_emi = NULL;
 275         } else {
 276                 BUG_ON(list_empty(&em->em_list) || em->em_num_items == 0);
 277                 emi = list_entry(em->em_list.prev,
 278                                  struct ocfs2_extent_map_item, ei_list);
 279                 list_move(&emi->ei_list, &em->em_list);
 280                 ocfs2_copy_emi_fields(emi, &ins);
 281         }
 282
 283         spin_unlock(&oi->ip_lock);
 284
 285 out:
 286         kfree(new_emi);
 287 }
 288
 289 static int ocfs2_last_eb_is_empty(struct inode *inode,
 290                                   struct ocfs2_dinode *di)
 291 {
 292         int ret, next_free;
 293         u64 last_eb_blk = le64_to_cpu(di->i_last_eb_blk);
 294         struct buffer_head *eb_bh = NULL;
 295         struct ocfs2_extent_block *eb;
 296         struct ocfs2_extent_list *el;
 297
 298         ret = ocfs2_read_extent_block(INODE_CACHE(inode), last_eb_blk, &eb_bh);
 299         if (ret) {
 300                 mlog_errno(ret);
 301                 goto out;
 302         }
 303
 304         eb = (struct ocfs2_extent_block *) eb_bh->b_data;
 305         el = &eb->h_list;
 306
 307         if (el->l_tree_depth) {
 308                 ocfs2_error(inode->i_sb,
 309                             "Inode %lu has non zero tree depth in leaf block %llu\n",
 310                             inode->i_ino,
 311                             (unsigned long long)eb_bh->b_blocknr);
 312                 ret = -EROFS;
 313                 goto out;
 314         }
 315
 316         next_free = le16_to_cpu(el->l_next_free_rec);
 317
 318         if (next_free == 0 ||
 319             (next_free == 1 && ocfs2_is_empty_extent(&el->l_recs[0])))
 320                 ret = 1;
 321
 322 out:
 323         brelse(eb_bh);
 324         return ret;
 325 }
 326
 327 /*
 328  * Return the 1st index within el which contains an extent start
 329  * larger than v_cluster.
 330  */
 331 static int ocfs2_search_for_hole_index(struct ocfs2_extent_list *el,
 332                                        u32 v_cluster)
 333 {
 334         int i;
 335         struct ocfs2_extent_rec *rec;
 336
 337         for(i = 0; i < le16_to_cpu(el->l_next_free_rec); i++) {
 338                 rec = &el->l_recs[i];
 339
 340                 if (v_cluster < le32_to_cpu(rec->e_cpos))
 341                         break;
 342         }
 343
 344         return i;
 345 }
 346
 347 /*
 348  * Figure out the size of a hole which starts at v_cluster within the given
 349  * extent list.
 350  *
 351  * If there is no more allocation past v_cluster, we return the maximum
 352  * cluster size minus v_cluster.
 353  *
 354  * If we have in-inode extents, then el points to the dinode list and
 355  * eb_bh is NULL. Otherwise, eb_bh should point to the extent block
 356  * containing el.
 357  */
 358 int ocfs2_figure_hole_clusters(struct ocfs2_caching_info *ci,
 359                                struct ocfs2_extent_list *el,
 360                                struct buffer_head *eb_bh,
 361                                u32 v_cluster,
 362                                u32 *num_clusters)
 363 {
 364         int ret, i;
 365         struct buffer_head *next_eb_bh = NULL;
 366         struct ocfs2_extent_block *eb, *next_eb;
 367
 368         i = ocfs2_search_for_hole_index(el, v_cluster);
 369
 370         if (i == le16_to_cpu(el->l_next_free_rec) && eb_bh) {
 371                 eb = (struct ocfs2_extent_block *)eb_bh->b_data;
 372
 373                 /*
 374                  * Check the next leaf for any extents.
 375                  */
 376
 377                 if (le64_to_cpu(eb->h_next_leaf_blk) == 0ULL)
 378                         goto no_more_extents;
 379
 380                 ret = ocfs2_read_extent_block(ci,
 381                                               le64_to_cpu(eb->h_next_leaf_blk),
 382                                               &next_eb_bh);
 383                 if (ret) {
 384                         mlog_errno(ret);
 385                         goto out;
 386                 }
 387
 388                 next_eb = (struct ocfs2_extent_block *)next_eb_bh->b_data;
 389                 el = &next_eb->h_list;
 390                 i = ocfs2_search_for_hole_index(el, v_cluster);
 391         }
 392
 393 no_more_extents:
 394         if (i == le16_to_cpu(el->l_next_free_rec)) {
 395                 /*
 396                  * We're at the end of our existing allocation. Just
 397                  * return the maximum number of clusters we could
 398                  * possibly allocate.
 399                  */
 400                 *num_clusters = UINT_MAX - v_cluster;
 401         } else {
 402                 *num_clusters = le32_to_cpu(el->l_recs[i].e_cpos) - v_cluster;
 403         }
 404
 405         ret = 0;
 406 out:
 407         brelse(next_eb_bh);
 408         return ret;
 409 }
 410
 411 static int ocfs2_get_clusters_nocache(struct inode *inode,
 412                                       struct buffer_head *di_bh,
 413                                       u32 v_cluster, unsigned int *hole_len,
 414                                       struct ocfs2_extent_rec *ret_rec,
 415                                       unsigned int *is_last)
 416 {
 417         int i, ret, tree_height, len;
 418         struct ocfs2_dinode *di;
 419         struct ocfs2_extent_block *uninitialized_var(eb);
 420         struct ocfs2_extent_list *el;
 421         struct ocfs2_extent_rec *rec;
 422         struct buffer_head *eb_bh = NULL;
 423
 424         memset(ret_rec, 0, sizeof(*ret_rec));
 425         if (is_last)
 426                 *is_last = 0;
 427
 428         di = (struct ocfs2_dinode *) di_bh->b_data;
 429         el = &di->id2.i_list;
 430         tree_height = le16_to_cpu(el->l_tree_depth);
 431
 432         if (tree_height > 0) {
 433                 ret = ocfs2_find_leaf(INODE_CACHE(inode), el, v_cluster,
 434                                       &eb_bh);
 435                 if (ret) {
 436                         mlog_errno(ret);
 437                         goto out;
 438                 }
 439
 440                 eb = (struct ocfs2_extent_block *) eb_bh->b_data;
 441                 el = &eb->h_list;
 442
 443                 if (el->l_tree_depth) {
 444                         ocfs2_error(inode->i_sb,
 445                                     "Inode %lu has non zero tree depth in leaf block %llu\n",
 446                                     inode->i_ino,
 447                                     (unsigned long long)eb_bh->b_blocknr);
 448                         ret = -EROFS;
 449                         goto out;
 450                 }
 451         }
 452
 453         i = ocfs2_search_extent_list(el, v_cluster);
 454         if (i == -1) {
 455                 /*
 456                  * Holes can be larger than the maximum size of an
 457                  * extent, so we return their lengths in a separate
 458                  * field.
 459                  */
 460                 if (hole_len) {
 461                         ret = ocfs2_figure_hole_clusters(INODE_CACHE(inode),
 462                                                          el, eb_bh,
 463                                                          v_cluster, &len);
 464                         if (ret) {
 465                                 mlog_errno(ret);
 466                                 goto out;
 467                         }
 468
 469                         *hole_len = len;
 470                 }
 471                 goto out_hole;
 472         }
 473
 474         rec = &el->l_recs[i];
 475
 476         BUG_ON(v_cluster < le32_to_cpu(rec->e_cpos));
 477
 478         if (!rec->e_blkno) {
 479                 ocfs2_error(inode->i_sb,
 480                             "Inode %lu has bad extent record (%u, %u, 0)\n",
 481                             inode->i_ino,
 482                             le32_to_cpu(rec->e_cpos),
 483                             ocfs2_rec_clusters(el, rec));
 484                 ret = -EROFS;
 485                 goto out;
 486         }
 487
 488         *ret_rec = *rec;
 489
 490         /*
 491          * Checking for last extent is potentially expensive - we
 492          * might have to look at the next leaf over to see if it's
 493          * empty.
 494          *
 495          * The first two checks are to see whether the caller even
 496          * cares for this information, and if the extent is at least
 497          * the last in it's list.
 498          *
 499          * If those hold true, then the extent is last if any of the
 500          * additional conditions hold true:
 501          *  - Extent list is in-inode
 502          *  - Extent list is right-most
 503          *  - Extent list is 2nd to rightmost, with empty right-most
 504          */
 505         if (is_last) {
 506                 if (i == (le16_to_cpu(el->l_next_free_rec) - 1)) {
 507                         if (tree_height == 0)
 508                                 *is_last = 1;
 509                         else if (eb->h_blkno == di->i_last_eb_blk)
 510                                 *is_last = 1;
 511                         else if (eb->h_next_leaf_blk == di->i_last_eb_blk) {
 512                                 ret = ocfs2_last_eb_is_empty(inode, di);
 513                                 if (ret < 0) {
 514                                         mlog_errno(ret);
 515                                         goto out;
 516                                 }
 517                                 if (ret == 1)
 518                                         *is_last = 1;
 519                         }
 520                 }
 521         }
 522
 523 out_hole:
 524         ret = 0;
 525 out:
 526         brelse(eb_bh);
 527         return ret;
 528 }
 529
 530 static void ocfs2_relative_extent_offsets(struct super_block *sb,
 531                                           u32 v_cluster,
 532                                           struct ocfs2_extent_rec *rec,
 533                                           u32 *p_cluster, u32 *num_clusters)
 534
 535 {
 536         u32 coff = v_cluster - le32_to_cpu(rec->e_cpos);
 537
 538         *p_cluster = ocfs2_blocks_to_clusters(sb, le64_to_cpu(rec->e_blkno));
 539         *p_cluster = *p_cluster + coff;
 540
 541         if (num_clusters)
 542                 *num_clusters = le16_to_cpu(rec->e_leaf_clusters) - coff;
 543 }
 544
 545 int ocfs2_xattr_get_clusters(struct inode *inode, u32 v_cluster,
 546                              u32 *p_cluster, u32 *num_clusters,
 547                              struct ocfs2_extent_list *el,
 548                              unsigned int *extent_flags)
 549 {
 550         int ret = 0, i;
 551         struct buffer_head *eb_bh = NULL;
 552         struct ocfs2_extent_block *eb;
 553         struct ocfs2_extent_rec *rec;
 554         u32 coff;
 555
 556         if (el->l_tree_depth) {
 557                 ret = ocfs2_find_leaf(INODE_CACHE(inode), el, v_cluster,
 558                                       &eb_bh);
 559                 if (ret) {
 560                         mlog_errno(ret);
 561                         goto out;
 562                 }
 563
 564                 eb = (struct ocfs2_extent_block *) eb_bh->b_data;
 565                 el = &eb->h_list;
 566
 567                 if (el->l_tree_depth) {
 568                         ocfs2_error(inode->i_sb,
 569                                     "Inode %lu has non zero tree depth in xattr leaf block %llu\n",
 570                                     inode->i_ino,
 571                                     (unsigned long long)eb_bh->b_blocknr);
 572                         ret = -EROFS;
 573                         goto out;
 574                 }
 575         }
 576
 577         i = ocfs2_search_extent_list(el, v_cluster);
 578         if (i == -1) {
 579                 ret = -EROFS;
 580                 mlog_errno(ret);
 581                 goto out;
 582         } else {
 583                 rec = &el->l_recs[i];
 584                 BUG_ON(v_cluster < le32_to_cpu(rec->e_cpos));
 585
 586                 if (!rec->e_blkno) {
 587                         ocfs2_error(inode->i_sb,
 588                                     "Inode %lu has bad extent record (%u, %u, 0) in xattr\n",
 589                                     inode->i_ino,
 590                                     le32_to_cpu(rec->e_cpos),
 591                                     ocfs2_rec_clusters(el, rec));
 592                         ret = -EROFS;
 593                         goto out;
 594                 }
 595                 coff = v_cluster - le32_to_cpu(rec->e_cpos);
 596                 *p_cluster = ocfs2_blocks_to_clusters(inode->i_sb,
 597                                                     le64_to_cpu(rec->e_blkno));
 598                 *p_cluster = *p_cluster + coff;
 599                 if (num_clusters)
 600                         *num_clusters = ocfs2_rec_clusters(el, rec) - coff;
 601
 602                 if (extent_flags)
 603                         *extent_flags = rec->e_flags;
 604         }
 605 out:
 606         if (eb_bh)
 607                 brelse(eb_bh);
 608         return ret;
 609 }
 610
 611 int ocfs2_get_clusters(struct inode *inode, u32 v_cluster,
 612                        u32 *p_cluster, u32 *num_clusters,
 613                        unsigned int *extent_flags)
 614 {
 615         int ret;
 616         unsigned int uninitialized_var(hole_len), flags = 0;
 617         struct buffer_head *di_bh = NULL;
 618         struct ocfs2_extent_rec rec;
 619
 620         if (OCFS2_I(inode)->ip_dyn_features & OCFS2_INLINE_DATA_FL) {
 621                 ret = -ERANGE;
 622                 mlog_errno(ret);
 623                 goto out;
 624         }
 625
 626         ret = ocfs2_extent_map_lookup(inode, v_cluster, p_cluster,
 627                                       num_clusters, extent_flags);
 628         if (ret == 0)
 629                 goto out;
 630
 631         ret = ocfs2_read_inode_block(inode, &di_bh);
 632         if (ret) {
 633                 mlog_errno(ret);
 634                 goto out;
 635         }
 636
 637         ret = ocfs2_get_clusters_nocache(inode, di_bh, v_cluster, &hole_len,
 638                                          &rec, NULL);
 639         if (ret) {
 640                 mlog_errno(ret);
 641                 goto out;
 642         }
 643
 644         if (rec.e_blkno == 0ULL) {
 645                 /*
 646                  * A hole was found. Return some canned values that
 647                  * callers can key on. If asked for, num_clusters will
 648                  * be populated with the size of the hole.
 649                  */
 650                 *p_cluster = 0;
 651                 if (num_clusters) {
 652                         *num_clusters = hole_len;
 653                 }
 654         } else {
 655                 ocfs2_relative_extent_offsets(inode->i_sb, v_cluster, &rec,
 656                                               p_cluster, num_clusters);
 657                 flags = rec.e_flags;
 658
 659                 ocfs2_extent_map_insert_rec(inode, &rec);
 660         }
 661
 662         if (extent_flags)
 663                 *extent_flags = flags;
 664
 665 out:
 666         brelse(di_bh);
 667         return ret;
 668 }
 669
 670 /*
 671  * This expects alloc_sem to be held. The allocation cannot change at
 672  * all while the map is in the process of being updated.
 673  */
 674 int ocfs2_extent_map_get_blocks(struct inode *inode, u64 v_blkno, u64 *p_blkno,
 675                                 u64 *ret_count, unsigned int *extent_flags)
 676 {
 677         int ret;
 678         int bpc = ocfs2_clusters_to_blocks(inode->i_sb, 1);
 679         u32 cpos, num_clusters, p_cluster;
 680         u64 boff = 0;
 681
 682         cpos = ocfs2_blocks_to_clusters(inode->i_sb, v_blkno);
 683
 684         ret = ocfs2_get_clusters(inode, cpos, &p_cluster, &num_clusters,
 685                                  extent_flags);
 686         if (ret) {
 687                 mlog_errno(ret);
 688                 goto out;
 689         }
 690
 691         /*
 692          * p_cluster == 0 indicates a hole.
 693          */
 694         if (p_cluster) {
 695                 boff = ocfs2_clusters_to_blocks(inode->i_sb, p_cluster);
 696                 boff += (v_blkno & (u64)(bpc - 1));
 697         }
 698
 699         *p_blkno = boff;
 700
 701         if (ret_count) {
 702                 *ret_count = ocfs2_clusters_to_blocks(inode->i_sb, num_clusters);
 703                 *ret_count -= v_blkno & (u64)(bpc - 1);
 704         }
 705
 706 out:
 707         return ret;
 708 }
 709
 710 /*
 711  * The ocfs2_fiemap_inline() may be a little bit misleading, since
 712  * it not only handles the fiemap for inlined files, but also deals
 713  * with the fast symlink, cause they have no difference for extent
 714  * mapping per se.
 715  */
 716 static int ocfs2_fiemap_inline(struct inode *inode, struct buffer_head *di_bh,
 717                                struct fiemap_extent_info *fieinfo,
 718                                u64 map_start)
 719 {
 720         int ret;
 721         unsigned int id_count;
 722         struct ocfs2_dinode *di;
 723         u64 phys;
 724         u32 flags = FIEMAP_EXTENT_DATA_INLINE|FIEMAP_EXTENT_LAST;
 725         struct ocfs2_inode_info *oi = OCFS2_I(inode);
 726
 727         di = (struct ocfs2_dinode *)di_bh->b_data;
 728         if (ocfs2_inode_is_fast_symlink(inode))
 729                 id_count = ocfs2_fast_symlink_chars(inode->i_sb);
 730         else
 731                 id_count = le16_to_cpu(di->id2.i_data.id_count);
 732
 733         if (map_start < id_count) {
 734                 phys = oi->ip_blkno << inode->i_sb->s_blocksize_bits;
 735                 if (ocfs2_inode_is_fast_symlink(inode))
 736                         phys += offsetof(struct ocfs2_dinode, id2.i_symlink);
 737                 else
 738                         phys += offsetof(struct ocfs2_dinode,
 739                                          id2.i_data.id_data);
 740
 741                 ret = fiemap_fill_next_extent(fieinfo, 0, phys, id_count,
 742                                               flags);
 743                 if (ret < 0)
 744                         return ret;
 745         }
 746
 747         return 0;
 748 }
 749
 750 #define OCFS2_FIEMAP_FLAGS      (FIEMAP_FLAG_SYNC)
 751
 752 int ocfs2_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
 753                  u64 map_start, u64 map_len)
 754 {
 755         int ret, is_last;
 756         u32 mapping_end, cpos;
 757         unsigned int hole_size;
 758         struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
 759         u64 len_bytes, phys_bytes, virt_bytes;
 760         struct buffer_head *di_bh = NULL;
 761         struct ocfs2_extent_rec rec;
 762
 763         ret = fiemap_check_flags(fieinfo, OCFS2_FIEMAP_FLAGS);
 764         if (ret)
 765                 return ret;
 766
 767         ret = ocfs2_inode_lock(inode, &di_bh, 0);
 768         if (ret) {
 769                 mlog_errno(ret);
 770                 goto out;
 771         }
 772
 773         down_read(&OCFS2_I(inode)->ip_alloc_sem);
 774
 775         /*
 776          * Handle inline-data and fast symlink separately.
 777          */
 778         if ((OCFS2_I(inode)->ip_dyn_features & OCFS2_INLINE_DATA_FL) ||
 779             ocfs2_inode_is_fast_symlink(inode)) {
 780                 ret = ocfs2_fiemap_inline(inode, di_bh, fieinfo, map_start);
 781                 goto out_unlock;
 782         }
 783
 784         cpos = map_start >> osb->s_clustersize_bits;
 785         mapping_end = ocfs2_clusters_for_bytes(inode->i_sb,
 786                                                map_start + map_len);
 787         is_last = 0;
 788         while (cpos < mapping_end && !is_last) {
 789                 u32 fe_flags;
 790
 791                 ret = ocfs2_get_clusters_nocache(inode, di_bh, cpos,
 792                                                  &hole_size, &rec, &is_last);
 793                 if (ret) {
 794                         mlog_errno(ret);
 795                         goto out_unlock;
 796                 }
 797
 798                 if (rec.e_blkno == 0ULL) {
 799                         cpos += hole_size;
 800                         continue;
 801                 }
 802
 803                 fe_flags = 0;
 804                 if (rec.e_flags & OCFS2_EXT_UNWRITTEN)
 805                         fe_flags |= FIEMAP_EXTENT_UNWRITTEN;
 806                 if (rec.e_flags & OCFS2_EXT_REFCOUNTED)
 807                         fe_flags |= FIEMAP_EXTENT_SHARED;
 808                 if (is_last)
 809                         fe_flags |= FIEMAP_EXTENT_LAST;
 810                 len_bytes = (u64)le16_to_cpu(rec.e_leaf_clusters) << osb->s_clustersize_bits;
 811                 phys_bytes = le64_to_cpu(rec.e_blkno) << osb->sb->s_blocksize_bits;
 812                 virt_bytes = (u64)le32_to_cpu(rec.e_cpos) << osb->s_clustersize_bits;
 813
 814                 ret = fiemap_fill_next_extent(fieinfo, virt_bytes, phys_bytes,
 815                                               len_bytes, fe_flags);
 816                 if (ret)
 817                         break;
 818
 819                 cpos = le32_to_cpu(rec.e_cpos)+ le16_to_cpu(rec.e_leaf_clusters);
 820         }
 821
 822         if (ret > 0)
 823                 ret = 0;
 824
 825 out_unlock:
 826         brelse(di_bh);
 827
 828         up_read(&OCFS2_I(inode)->ip_alloc_sem);
 829
 830         ocfs2_inode_unlock(inode, 0);
 831 out:
 832
 833         return ret;
 834 }
 835
 836 /* Is IO overwriting allocated blocks? */
 837 int ocfs2_overwrite_io(struct inode *inode, struct buffer_head *di_bh,
 838                        u64 map_start, u64 map_len)
 839 {
 840         int ret = 0, is_last;
 841         u32 mapping_end, cpos;
 842         struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
 843         struct ocfs2_extent_rec rec;
 844
 845         if (OCFS2_I(inode)->ip_dyn_features & OCFS2_INLINE_DATA_FL) {
 846                 if (ocfs2_size_fits_inline_data(di_bh, map_start + map_len))
 847                         return ret;
 848                 else
 849                         return -EAGAIN;
 850         }
 851
 852         cpos = map_start >> osb->s_clustersize_bits;
 853         mapping_end = ocfs2_clusters_for_bytes(inode->i_sb,
 854                                                map_start + map_len);
 855         is_last = 0;
 856         while (cpos < mapping_end && !is_last) {
 857                 ret = ocfs2_get_clusters_nocache(inode, di_bh, cpos,
 858                                                  NULL, &rec, &is_last);
 859                 if (ret) {
 860                         mlog_errno(ret);
 861                         goto out;
 862                 }
 863
 864                 if (rec.e_blkno == 0ULL)
 865                         break;
 866
 867                 if (rec.e_flags & OCFS2_EXT_REFCOUNTED)
 868                         break;
 869
 870                 cpos = le32_to_cpu(rec.e_cpos) +
 871                         le16_to_cpu(rec.e_leaf_clusters);
 872         }
 873
 874         if (cpos < mapping_end)
 875                 ret = -EAGAIN;
 876 out:
 877         return ret;
 878 }
 879
 880 int ocfs2_seek_data_hole_offset(struct file *file, loff_t *offset, int whence)
 881 {
 882         struct inode *inode = file->f_mapping->host;
 883         int ret;
 884         unsigned int is_last = 0, is_data = 0;
 885         u16 cs_bits = OCFS2_SB(inode->i_sb)->s_clustersize_bits;
 886         u32 cpos, cend, clen, hole_size;
 887         u64 extoff, extlen;
 888         struct buffer_head *di_bh = NULL;
 889         struct ocfs2_extent_rec rec;
 890
 891         BUG_ON(whence != SEEK_DATA && whence != SEEK_HOLE);
 892
 893         ret = ocfs2_inode_lock(inode, &di_bh, 0);
 894         if (ret) {
 895                 mlog_errno(ret);
 896                 goto out;
 897         }
 898
 899         down_read(&OCFS2_I(inode)->ip_alloc_sem);
 900
 901         if (*offset >= i_size_read(inode)) {
 902                 ret = -ENXIO;
 903                 goto out_unlock;
 904         }
 905
 906         if (OCFS2_I(inode)->ip_dyn_features & OCFS2_INLINE_DATA_FL) {
 907                 if (whence == SEEK_HOLE)
 908                         *offset = i_size_read(inode);
 909                 goto out_unlock;
 910         }
 911
 912         clen = 0;
 913         cpos = *offset >> cs_bits;
 914         cend = ocfs2_clusters_for_bytes(inode->i_sb, i_size_read(inode));
 915
 916         while (cpos < cend && !is_last) {
 917                 ret = ocfs2_get_clusters_nocache(inode, di_bh, cpos, &hole_size,
 918                                                  &rec, &is_last);
 919                 if (ret) {
 920                         mlog_errno(ret);
 921                         goto out_unlock;
 922                 }
 923
 924                 extoff = cpos;
 925                 extoff <<= cs_bits;
 926
 927                 if (rec.e_blkno == 0ULL) {
 928                         clen = hole_size;
 929                         is_data = 0;
 930                 } else {
 931                         clen = le16_to_cpu(rec.e_leaf_clusters) -
 932                                 (cpos - le32_to_cpu(rec.e_cpos));
 933                         is_data = (rec.e_flags & OCFS2_EXT_UNWRITTEN) ?  0 : 1;
 934                 }
 935
 936                 if ((!is_data && whence == SEEK_HOLE) ||
 937                     (is_data && whence == SEEK_DATA)) {
 938                         if (extoff > *offset)
 939                                 *offset = extoff;
 940                         goto out_unlock;
 941                 }
 942
 943                 if (!is_last)
 944                         cpos += clen;
 945         }
 946
 947         if (whence == SEEK_HOLE) {
 948                 extoff = cpos;
 949                 extoff <<= cs_bits;
 950                 extlen = clen;
 951                 extlen <<=  cs_bits;
 952
 953                 if ((extoff + extlen) > i_size_read(inode))
 954                         extlen = i_size_read(inode) - extoff;
 955                 extoff += extlen;
 956                 if (extoff > *offset)
 957                         *offset = extoff;
 958                 goto out_unlock;
 959         }
 960
 961         ret = -ENXIO;
 962
 963 out_unlock:
 964
 965         brelse(di_bh);
 966
 967         up_read(&OCFS2_I(inode)->ip_alloc_sem);
 968
 969         ocfs2_inode_unlock(inode, 0);
 970 out:
 971         return ret;
 972 }
 973
 974 int ocfs2_read_virt_blocks(struct inode *inode, u64 v_block, int nr,
 975                            struct buffer_head *bhs[], int flags,
 976                            int (*validate)(struct super_block *sb,
 977                                            struct buffer_head *bh))
 978 {
 979         int rc = 0;
 980         u64 p_block, p_count;
 981         int i, count, done = 0;
 982
 983         trace_ocfs2_read_virt_blocks(
 984              inode, (unsigned long long)v_block, nr, bhs, flags,
 985              validate);
 986
 987         if (((v_block + nr - 1) << inode->i_sb->s_blocksize_bits) >=
 988             i_size_read(inode)) {
 989                 BUG_ON(!(flags & OCFS2_BH_READAHEAD));
 990                 goto out;
 991         }
 992
 993         while (done < nr) {
 994                 down_read(&OCFS2_I(inode)->ip_alloc_sem);
 995                 rc = ocfs2_extent_map_get_blocks(inode, v_block + done,
 996                                                  &p_block, &p_count, NULL);
 997                 up_read(&OCFS2_I(inode)->ip_alloc_sem);
 998                 if (rc) {
 999                         mlog_errno(rc);
1000                         break;
1001                 }
1002
1003                 if (!p_block) {
1004                         rc = -EIO;
1005                         mlog(ML_ERROR,
1006                              "Inode #%llu contains a hole at offset %llu\n",
1007                              (unsigned long long)OCFS2_I(inode)->ip_blkno,
1008                              (unsigned long long)(v_block + done) <<
1009                              inode->i_sb->s_blocksize_bits);
1010                         break;
1011                 }
1012
1013                 count = nr - done;
1014                 if (p_count < count)
1015                         count = p_count;
1016
1017                 /*
1018                  * If the caller passed us bhs, they should have come
1019                  * from a previous readahead call to this function.  Thus,
1020                  * they should have the right b_blocknr.
1021                  */
1022                 for (i = 0; i < count; i++) {
1023                         if (!bhs[done + i])
1024                                 continue;
1025                         BUG_ON(bhs[done + i]->b_blocknr != (p_block + i));
1026                 }
1027
1028                 rc = ocfs2_read_blocks(INODE_CACHE(inode), p_block, count,
1029                                        bhs + done, flags, validate);
1030                 if (rc) {
1031                         mlog_errno(rc);
1032                         break;
1033                 }
1034                 done += count;
1035         }
1036
1037 out:
1038         return rc;
1039 }
1040
1041