git.oblomov.eu Git - linux-2.6/blob - 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  * In-memory extent map for OCFS2.  Man, this code was prettier in
   7  * the library.
   8  *
   9  * Copyright (C) 2004 Oracle.  All rights reserved.
  10  *
  11  * This program is free software; you can redistribute it and/or
  12  * modify it under the terms of the GNU General Public
  13  * License, version 2,  as published by the Free Software Foundation.
  14  *
  15  * This program is distributed in the hope that it will be useful,
  16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  18  * General Public License for more details.
  19  *
  20  * You should have received a copy of the GNU General Public
  21  * License along with this program; if not, write to the
  22  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  23  * Boston, MA 021110-1307, USA.
  24  */
  25
  26 #include <linux/fs.h>
  27 #include <linux/init.h>
  28 #include <linux/types.h>
  29 #include <linux/slab.h>
  30 #include <linux/rbtree.h>
  31
  32 #define MLOG_MASK_PREFIX ML_EXTENT_MAP
  33 #include <cluster/masklog.h>
  34
  35 #include "ocfs2.h"
  36
  37 #include "extent_map.h"
  38 #include "inode.h"
  39 #include "super.h"
  40
  41 #include "buffer_head_io.h"
  42
  43
  44 /*
  45  * SUCK SUCK SUCK
  46  * Our headers are so bad that struct ocfs2_extent_map is in ocfs.h
  47  */
  48
  49 struct ocfs2_extent_map_entry {
  50         struct rb_node e_node;
  51         int e_tree_depth;
  52         struct ocfs2_extent_rec e_rec;
  53 };
  54
  55 struct ocfs2_em_insert_context {
  56         int need_left;
  57         int need_right;
  58         struct ocfs2_extent_map_entry *new_ent;
  59         struct ocfs2_extent_map_entry *old_ent;
  60         struct ocfs2_extent_map_entry *left_ent;
  61         struct ocfs2_extent_map_entry *right_ent;
  62 };
  63
  64 static kmem_cache_t *ocfs2_em_ent_cachep = NULL;
  65
  66
  67 static struct ocfs2_extent_map_entry *
  68 ocfs2_extent_map_lookup(struct ocfs2_extent_map *em,
  69                         u32 cpos, u32 clusters,
  70                         struct rb_node ***ret_p,
  71                         struct rb_node **ret_parent);
  72 static int ocfs2_extent_map_insert(struct inode *inode,
  73                                    struct ocfs2_extent_rec *rec,
  74                                    int tree_depth);
  75 static int ocfs2_extent_map_insert_entry(struct ocfs2_extent_map *em,
  76                                          struct ocfs2_extent_map_entry *ent);
  77 static int ocfs2_extent_map_find_leaf(struct inode *inode,
  78                                       u32 cpos, u32 clusters,
  79                                       struct ocfs2_extent_list *el);
  80 static int ocfs2_extent_map_lookup_read(struct inode *inode,
  81                                         u32 cpos, u32 clusters,
  82                                         struct ocfs2_extent_map_entry **ret_ent);
  83 static int ocfs2_extent_map_try_insert(struct inode *inode,
  84                                        struct ocfs2_extent_rec *rec,
  85                                        int tree_depth,
  86                                        struct ocfs2_em_insert_context *ctxt);
  87
  88 /* returns 1 only if the rec contains all the given clusters -- that is that
  89  * rec's cpos is <= the cluster cpos and that the rec endpoint (cpos +
  90  * clusters) is >= the argument's endpoint */
  91 static int ocfs2_extent_rec_contains_clusters(struct ocfs2_extent_rec *rec,
  92                                               u32 cpos, u32 clusters)
  93 {
  94         if (le32_to_cpu(rec->e_cpos) > cpos)
  95                 return 0;
  96         if (cpos + clusters > le32_to_cpu(rec->e_cpos) +
  97                               le32_to_cpu(rec->e_clusters))
  98                 return 0;
  99         return 1;
 100 }
 101
 102
 103 /*
 104  * Find an entry in the tree that intersects the region passed in.
 105  * Note that this will find straddled intervals, it is up to the
 106  * callers to enforce any boundary conditions.
 107  *
 108  * Callers must hold ip_lock.  This lookup is not guaranteed to return
 109  * a tree_depth 0 match, and as such can race inserts if the lock
 110  * were not held.
 111  *
 112  * The rb_node garbage lets insertion share the search.  Trivial
 113  * callers pass NULL.
 114  */
 115 static struct ocfs2_extent_map_entry *
 116 ocfs2_extent_map_lookup(struct ocfs2_extent_map *em,
 117                         u32 cpos, u32 clusters,
 118                         struct rb_node ***ret_p,
 119                         struct rb_node **ret_parent)
 120 {
 121         struct rb_node **p = &em->em_extents.rb_node;
 122         struct rb_node *parent = NULL;
 123         struct ocfs2_extent_map_entry *ent = NULL;
 124
 125         while (*p)
 126         {
 127                 parent = *p;
 128                 ent = rb_entry(parent, struct ocfs2_extent_map_entry,
 129                                e_node);
 130                 if ((cpos + clusters) <= le32_to_cpu(ent->e_rec.e_cpos)) {
 131                         p = &(*p)->rb_left;
 132                         ent = NULL;
 133                 } else if (cpos >= (le32_to_cpu(ent->e_rec.e_cpos) +
 134                                     le32_to_cpu(ent->e_rec.e_clusters))) {
 135                         p = &(*p)->rb_right;
 136                         ent = NULL;
 137                 } else
 138                         break;
 139         }
 140
 141         if (ret_p != NULL)
 142                 *ret_p = p;
 143         if (ret_parent != NULL)
 144                 *ret_parent = parent;
 145         return ent;
 146 }
 147
 148 /*
 149  * Find the leaf containing the interval we want.  While we're on our
 150  * way down the tree, fill in every record we see at any depth, because
 151  * we might want it later.
 152  *
 153  * Note that this code is run without ip_lock.  That's because it
 154  * sleeps while reading.  If someone is also filling the extent list at
 155  * the same time we are, we might have to restart.
 156  */
 157 static int ocfs2_extent_map_find_leaf(struct inode *inode,
 158                                       u32 cpos, u32 clusters,
 159                                       struct ocfs2_extent_list *el)
 160 {
 161         int i, ret;
 162         struct buffer_head *eb_bh = NULL;
 163         u64 blkno;
 164         u32 rec_end;
 165         struct ocfs2_extent_block *eb;
 166         struct ocfs2_extent_rec *rec;
 167
 168         /*
 169          * The bh data containing the el cannot change here, because
 170          * we hold alloc_sem.  So we can do this without other
 171          * locks.
 172          */
 173         while (el->l_tree_depth)
 174         {
 175                 blkno = 0;
 176                 for (i = 0; i < le16_to_cpu(el->l_next_free_rec); i++) {
 177                         rec = &el->l_recs[i];
 178                         rec_end = (le32_to_cpu(rec->e_cpos) +
 179                                    le32_to_cpu(rec->e_clusters));
 180
 181                         ret = -EBADR;
 182                         if (rec_end > OCFS2_I(inode)->ip_clusters) {
 183                                 mlog_errno(ret);
 184                                 ocfs2_error(inode->i_sb,
 185                                             "Extent %d at e_blkno %llu of inode %llu goes past ip_clusters of %u\n",
 186                                             i,
 187                                             (unsigned long long)le64_to_cpu(rec->e_blkno),
 188                                             (unsigned long long)OCFS2_I(inode)->ip_blkno,
 189                                             OCFS2_I(inode)->ip_clusters);
 190                                 goto out_free;
 191                         }
 192
 193                         if (rec_end <= cpos) {
 194                                 ret = ocfs2_extent_map_insert(inode, rec,
 195                                                 le16_to_cpu(el->l_tree_depth));
 196                                 if (ret && (ret != -EEXIST)) {
 197                                         mlog_errno(ret);
 198                                         goto out_free;
 199                                 }
 200                                 continue;
 201                         }
 202                         if ((cpos + clusters) <= le32_to_cpu(rec->e_cpos)) {
 203                                 ret = ocfs2_extent_map_insert(inode, rec,
 204                                                 le16_to_cpu(el->l_tree_depth));
 205                                 if (ret && (ret != -EEXIST)) {
 206                                         mlog_errno(ret);
 207                                         goto out_free;
 208                                 }
 209                                 continue;
 210                         }
 211
 212                         /*
 213                          * We've found a record that matches our
 214                          * interval.  We don't insert it because we're
 215                          * about to traverse it.
 216                          */
 217
 218                         /* Check to see if we're stradling */
 219                         ret = -ESRCH;
 220                         if (!ocfs2_extent_rec_contains_clusters(rec,
 221                                                                 cpos,
 222                                                                 clusters)) {
 223                                 mlog_errno(ret);
 224                                 goto out_free;
 225                         }
 226
 227                         /*
 228                          * If we've already found a record, the el has
 229                          * two records covering the same interval.
 230                          * EEEK!
 231                          */
 232                         ret = -EBADR;
 233                         if (blkno) {
 234                                 mlog_errno(ret);
 235                                 ocfs2_error(inode->i_sb,
 236                                             "Multiple extents for (cpos = %u, clusters = %u) on inode %llu; e_blkno %llu and rec %d at e_blkno %llu\n",
 237                                             cpos, clusters,
 238                                             (unsigned long long)OCFS2_I(inode)->ip_blkno,
 239                                             (unsigned long long)blkno, i,
 240                                             (unsigned long long)le64_to_cpu(rec->e_blkno));
 241                                 goto out_free;
 242                         }
 243
 244                         blkno = le64_to_cpu(rec->e_blkno);
 245                 }
 246
 247                 /*
 248                  * We don't support holes, and we're still up
 249                  * in the branches, so we'd better have found someone
 250                  */
 251                 ret = -EBADR;
 252                 if (!blkno) {
 253                         ocfs2_error(inode->i_sb,
 254                                     "No record found for (cpos = %u, clusters = %u) on inode %llu\n",
 255                                     cpos, clusters,
 256                                     (unsigned long long)OCFS2_I(inode)->ip_blkno);
 257                         mlog_errno(ret);
 258                         goto out_free;
 259                 }
 260
 261                 if (eb_bh) {
 262                         brelse(eb_bh);
 263                         eb_bh = NULL;
 264                 }
 265                 ret = ocfs2_read_block(OCFS2_SB(inode->i_sb),
 266                                        blkno, &eb_bh, OCFS2_BH_CACHED,
 267                                        inode);
 268                 if (ret) {
 269                         mlog_errno(ret);
 270                         goto out_free;
 271                 }
 272                 eb = (struct ocfs2_extent_block *)eb_bh->b_data;
 273                 if (!OCFS2_IS_VALID_EXTENT_BLOCK(eb)) {
 274                         OCFS2_RO_ON_INVALID_EXTENT_BLOCK(inode->i_sb, eb);
 275                         ret = -EIO;
 276                         goto out_free;
 277                 }
 278                 el = &eb->h_list;
 279         }
 280
 281         BUG_ON(el->l_tree_depth);
 282
 283         for (i = 0; i < le16_to_cpu(el->l_next_free_rec); i++) {
 284                 rec = &el->l_recs[i];
 285
 286                 if ((le32_to_cpu(rec->e_cpos) + le32_to_cpu(rec->e_clusters)) >
 287                     OCFS2_I(inode)->ip_clusters) {
 288                         ret = -EBADR;
 289                         mlog_errno(ret);
 290                         ocfs2_error(inode->i_sb,
 291                                     "Extent %d at e_blkno %llu of inode %llu goes past ip_clusters of %u\n",
 292                                     i,
 293                                     (unsigned long long)le64_to_cpu(rec->e_blkno),
 294                                     (unsigned long long)OCFS2_I(inode)->ip_blkno,
 295                                     OCFS2_I(inode)->ip_clusters);
 296                         return ret;
 297                 }
 298
 299                 ret = ocfs2_extent_map_insert(inode, rec,
 300                                               le16_to_cpu(el->l_tree_depth));
 301                 if (ret && (ret != -EEXIST)) {
 302                         mlog_errno(ret);
 303                         goto out_free;
 304                 }
 305         }
 306
 307         ret = 0;
 308
 309 out_free:
 310         if (eb_bh)
 311                 brelse(eb_bh);
 312
 313         return ret;
 314 }
 315
 316 /*
 317  * This lookup actually will read from disk.  It has one invariant:
 318  * It will never re-traverse blocks.  This means that all inserts should
 319  * be new regions or more granular regions (both allowed by insert).
 320  */
 321 static int ocfs2_extent_map_lookup_read(struct inode *inode,
 322                                         u32 cpos,
 323                                         u32 clusters,
 324                                         struct ocfs2_extent_map_entry **ret_ent)
 325 {
 326         int ret;
 327         u64 blkno;
 328         struct ocfs2_extent_map *em = &OCFS2_I(inode)->ip_map;
 329         struct ocfs2_extent_map_entry *ent;
 330         struct buffer_head *bh = NULL;
 331         struct ocfs2_extent_block *eb;
 332         struct ocfs2_dinode *di;
 333         struct ocfs2_extent_list *el;
 334
 335         spin_lock(&OCFS2_I(inode)->ip_lock);
 336         ent = ocfs2_extent_map_lookup(em, cpos, clusters, NULL, NULL);
 337         if (ent) {
 338                 if (!ent->e_tree_depth) {
 339                         spin_unlock(&OCFS2_I(inode)->ip_lock);
 340                         *ret_ent = ent;
 341                         return 0;
 342                 }
 343                 blkno = le64_to_cpu(ent->e_rec.e_blkno);
 344                 spin_unlock(&OCFS2_I(inode)->ip_lock);
 345
 346                 ret = ocfs2_read_block(OCFS2_SB(inode->i_sb), blkno, &bh,
 347                                        OCFS2_BH_CACHED, inode);
 348                 if (ret) {
 349                         mlog_errno(ret);
 350                         if (bh)
 351                                 brelse(bh);
 352                         return ret;
 353                 }
 354                 eb = (struct ocfs2_extent_block *)bh->b_data;
 355                 if (!OCFS2_IS_VALID_EXTENT_BLOCK(eb)) {
 356                         OCFS2_RO_ON_INVALID_EXTENT_BLOCK(inode->i_sb, eb);
 357                         brelse(bh);
 358                         return -EIO;
 359                 }
 360                 el = &eb->h_list;
 361         } else {
 362                 spin_unlock(&OCFS2_I(inode)->ip_lock);
 363
 364                 ret = ocfs2_read_block(OCFS2_SB(inode->i_sb),
 365                                        OCFS2_I(inode)->ip_blkno, &bh,
 366                                        OCFS2_BH_CACHED, inode);
 367                 if (ret) {
 368                         mlog_errno(ret);
 369                         if (bh)
 370                                 brelse(bh);
 371                         return ret;
 372                 }
 373                 di = (struct ocfs2_dinode *)bh->b_data;
 374                 if (!OCFS2_IS_VALID_DINODE(di)) {
 375                         brelse(bh);
 376                         OCFS2_RO_ON_INVALID_DINODE(inode->i_sb, di);
 377                         return -EIO;
 378                 }
 379                 el = &di->id2.i_list;
 380         }
 381
 382         ret = ocfs2_extent_map_find_leaf(inode, cpos, clusters, el);
 383         brelse(bh);
 384         if (ret) {
 385                 mlog_errno(ret);
 386                 return ret;
 387         }
 388
 389         ent = ocfs2_extent_map_lookup(em, cpos, clusters, NULL, NULL);
 390         if (!ent) {
 391                 ret = -ESRCH;
 392                 mlog_errno(ret);
 393                 return ret;
 394         }
 395
 396         /* FIXME: Make sure this isn't a corruption */
 397         BUG_ON(ent->e_tree_depth);
 398
 399         *ret_ent = ent;
 400
 401         return 0;
 402 }
 403
 404 /*
 405  * Callers must hold ip_lock.  This can insert pieces of the tree,
 406  * thus racing lookup if the lock weren't held.
 407  */
 408 static int ocfs2_extent_map_insert_entry(struct ocfs2_extent_map *em,
 409                                          struct ocfs2_extent_map_entry *ent)
 410 {
 411         struct rb_node **p, *parent;
 412         struct ocfs2_extent_map_entry *old_ent;
 413
 414         old_ent = ocfs2_extent_map_lookup(em, le32_to_cpu(ent->e_rec.e_cpos),
 415                                           le32_to_cpu(ent->e_rec.e_clusters),
 416                                           &p, &parent);
 417         if (old_ent)
 418                 return -EEXIST;
 419
 420         rb_link_node(&ent->e_node, parent, p);
 421         rb_insert_color(&ent->e_node, &em->em_extents);
 422
 423         return 0;
 424 }
 425
 426
 427 /*
 428  * Simple rule: on any return code other than -EAGAIN, anything left
 429  * in the insert_context will be freed.
 430  *
 431  * Simple rule #2: A return code of -EEXIST from this function or
 432  * its calls to ocfs2_extent_map_insert_entry() signifies that another
 433  * thread beat us to the insert.  It is not an actual error, but it
 434  * tells the caller we have no more work to do.
 435  */
 436 static int ocfs2_extent_map_try_insert(struct inode *inode,
 437                                        struct ocfs2_extent_rec *rec,
 438                                        int tree_depth,
 439                                        struct ocfs2_em_insert_context *ctxt)
 440 {
 441         int ret;
 442         struct ocfs2_extent_map *em = &OCFS2_I(inode)->ip_map;
 443         struct ocfs2_extent_map_entry *old_ent;
 444
 445         ctxt->need_left = 0;
 446         ctxt->need_right = 0;
 447         ctxt->old_ent = NULL;
 448
 449         spin_lock(&OCFS2_I(inode)->ip_lock);
 450         ret = ocfs2_extent_map_insert_entry(em, ctxt->new_ent);
 451         if (!ret) {
 452                 ctxt->new_ent = NULL;
 453                 goto out_unlock;
 454         }
 455
 456         /* Since insert_entry failed, the map MUST have old_ent */
 457         old_ent = ocfs2_extent_map_lookup(em, le32_to_cpu(rec->e_cpos),
 458                                           le32_to_cpu(rec->e_clusters),
 459                                           NULL, NULL);
 460
 461         BUG_ON(!old_ent);
 462
 463         if (old_ent->e_tree_depth < tree_depth) {
 464                 /* Another thread beat us to the lower tree_depth */
 465                 ret = -EEXIST;
 466                 goto out_unlock;
 467         }
 468
 469         if (old_ent->e_tree_depth == tree_depth) {
 470                 /*
 471                  * Another thread beat us to this tree_depth.
 472                  * Let's make sure we agree with that thread (the
 473                  * extent_rec should be identical).
 474                  */
 475                 if (!memcmp(rec, &old_ent->e_rec,
 476                             sizeof(struct ocfs2_extent_rec)))
 477                         ret = 0;
 478                 else
 479                         /* FIXME: Should this be ESRCH/EBADR??? */
 480                         ret = -EEXIST;
 481
 482                 goto out_unlock;
 483         }
 484
 485         /*
 486          * We do it in this order specifically so that no actual tree
 487          * changes occur until we have all the pieces we need.  We
 488          * don't want malloc failures to leave an inconsistent tree.
 489          * Whenever we drop the lock, another process could be
 490          * inserting.  Also note that, if another process just beat us
 491          * to an insert, we might not need the same pieces we needed
 492          * the first go round.  In the end, the pieces we need will
 493          * be used, and the pieces we don't will be freed.
 494          */
 495         ctxt->need_left = !!(le32_to_cpu(rec->e_cpos) >
 496                              le32_to_cpu(old_ent->e_rec.e_cpos));
 497         ctxt->need_right = !!((le32_to_cpu(old_ent->e_rec.e_cpos) +
 498                                le32_to_cpu(old_ent->e_rec.e_clusters)) >
 499                               (le32_to_cpu(rec->e_cpos) + le32_to_cpu(rec->e_clusters)));
 500         ret = -EAGAIN;
 501         if (ctxt->need_left) {
 502                 if (!ctxt->left_ent)
 503                         goto out_unlock;
 504                 *(ctxt->left_ent) = *old_ent;
 505                 ctxt->left_ent->e_rec.e_clusters =
 506                         cpu_to_le32(le32_to_cpu(rec->e_cpos) -
 507                                     le32_to_cpu(ctxt->left_ent->e_rec.e_cpos));
 508         }
 509         if (ctxt->need_right) {
 510                 if (!ctxt->right_ent)
 511                         goto out_unlock;
 512                 *(ctxt->right_ent) = *old_ent;
 513                 ctxt->right_ent->e_rec.e_cpos =
 514                         cpu_to_le32(le32_to_cpu(rec->e_cpos) +
 515                                     le32_to_cpu(rec->e_clusters));
 516                 ctxt->right_ent->e_rec.e_clusters =
 517                         cpu_to_le32((le32_to_cpu(old_ent->e_rec.e_cpos) +
 518                                      le32_to_cpu(old_ent->e_rec.e_clusters)) -
 519                                     le32_to_cpu(ctxt->right_ent->e_rec.e_cpos));
 520         }
 521
 522         rb_erase(&old_ent->e_node, &em->em_extents);
 523         /* Now that he's erased, set him up for deletion */
 524         ctxt->old_ent = old_ent;
 525
 526         if (ctxt->need_left) {
 527                 ret = ocfs2_extent_map_insert_entry(em,
 528                                                     ctxt->left_ent);
 529                 if (ret)
 530                         goto out_unlock;
 531                 ctxt->left_ent = NULL;
 532         }
 533
 534         if (ctxt->need_right) {
 535                 ret = ocfs2_extent_map_insert_entry(em,
 536                                                     ctxt->right_ent);
 537                 if (ret)
 538                         goto out_unlock;
 539                 ctxt->right_ent = NULL;
 540         }
 541
 542         ret = ocfs2_extent_map_insert_entry(em, ctxt->new_ent);
 543
 544         if (!ret)
 545                 ctxt->new_ent = NULL;
 546
 547 out_unlock:
 548         spin_unlock(&OCFS2_I(inode)->ip_lock);
 549
 550         return ret;
 551 }
 552
 553
 554 static int ocfs2_extent_map_insert(struct inode *inode,
 555                                    struct ocfs2_extent_rec *rec,
 556                                    int tree_depth)
 557 {
 558         int ret;
 559         struct ocfs2_em_insert_context ctxt = {0, };
 560
 561         if ((le32_to_cpu(rec->e_cpos) + le32_to_cpu(rec->e_clusters)) >
 562             OCFS2_I(inode)->ip_map.em_clusters) {
 563                 ret = -EBADR;
 564                 mlog_errno(ret);
 565                 return ret;
 566         }
 567
 568         /* Zero e_clusters means a truncated tail record.  It better be EOF */
 569         if (!rec->e_clusters) {
 570                 if ((le32_to_cpu(rec->e_cpos) + le32_to_cpu(rec->e_clusters)) !=
 571                     OCFS2_I(inode)->ip_map.em_clusters) {
 572                         ret = -EBADR;
 573                         mlog_errno(ret);
 574                         ocfs2_error(inode->i_sb,
 575                                     "Zero e_clusters on non-tail extent record at e_blkno %llu on inode %llu\n",
 576                                     (unsigned long long)le64_to_cpu(rec->e_blkno),
 577                                     (unsigned long long)OCFS2_I(inode)->ip_blkno);
 578                         return ret;
 579                 }
 580
 581                 /* Ignore the truncated tail */
 582                 return 0;
 583         }
 584
 585         ret = -ENOMEM;
 586         ctxt.new_ent = kmem_cache_alloc(ocfs2_em_ent_cachep,
 587                                         GFP_NOFS);
 588         if (!ctxt.new_ent) {
 589                 mlog_errno(ret);
 590                 return ret;
 591         }
 592
 593         ctxt.new_ent->e_rec = *rec;
 594         ctxt.new_ent->e_tree_depth = tree_depth;
 595
 596         do {
 597                 ret = -ENOMEM;
 598                 if (ctxt.need_left && !ctxt.left_ent) {
 599                         ctxt.left_ent =
 600                                 kmem_cache_alloc(ocfs2_em_ent_cachep,
 601                                                  GFP_NOFS);
 602                         if (!ctxt.left_ent)
 603                                 break;
 604                 }
 605                 if (ctxt.need_right && !ctxt.right_ent) {
 606                         ctxt.right_ent =
 607                                 kmem_cache_alloc(ocfs2_em_ent_cachep,
 608                                                  GFP_NOFS);
 609                         if (!ctxt.right_ent)
 610                                 break;
 611                 }
 612
 613                 ret = ocfs2_extent_map_try_insert(inode, rec,
 614                                                   tree_depth, &ctxt);
 615         } while (ret == -EAGAIN);
 616
 617         if ((ret < 0) && (ret != -EEXIST))
 618                 mlog_errno(ret);
 619
 620         if (ctxt.left_ent)
 621                 kmem_cache_free(ocfs2_em_ent_cachep, ctxt.left_ent);
 622         if (ctxt.right_ent)
 623                 kmem_cache_free(ocfs2_em_ent_cachep, ctxt.right_ent);
 624         if (ctxt.old_ent)
 625                 kmem_cache_free(ocfs2_em_ent_cachep, ctxt.old_ent);
 626         if (ctxt.new_ent)
 627                 kmem_cache_free(ocfs2_em_ent_cachep, ctxt.new_ent);
 628
 629         return ret;
 630 }
 631
 632 /*
 633  * Append this record to the tail of the extent map.  It must be
 634  * tree_depth 0.  The record might be an extension of an existing
 635  * record, and as such that needs to be handled.  eg:
 636  *
 637  * Existing record in the extent map:
 638  *
 639  *      cpos = 10, len = 10
 640  *      |---------|
 641  *
 642  * New Record:
 643  *
 644  *      cpos = 10, len = 20
 645  *      |------------------|
 646  *
 647  * The passed record is the new on-disk record.  The new_clusters value
 648  * is how many clusters were added to the file.  If the append is a
 649  * contiguous append, the new_clusters has been added to
 650  * rec->e_clusters.  If the append is an entirely new extent, then
 651  * rec->e_clusters is == new_clusters.
 652  */
 653 int ocfs2_extent_map_append(struct inode *inode,
 654                             struct ocfs2_extent_rec *rec,
 655                             u32 new_clusters)
 656 {
 657         int ret;
 658         struct ocfs2_extent_map *em = &OCFS2_I(inode)->ip_map;
 659         struct ocfs2_extent_map_entry *ent;
 660         struct ocfs2_extent_rec *old;
 661
 662         BUG_ON(!new_clusters);
 663         BUG_ON(le32_to_cpu(rec->e_clusters) < new_clusters);
 664
 665         if (em->em_clusters < OCFS2_I(inode)->ip_clusters) {
 666                 /*
 667                  * Size changed underneath us on disk.  Drop any
 668                  * straddling records and update our idea of
 669                  * i_clusters
 670                  */
 671                 ocfs2_extent_map_drop(inode, em->em_clusters - 1);
 672                 em->em_clusters = OCFS2_I(inode)->ip_clusters;
 673         }
 674
 675         mlog_bug_on_msg((le32_to_cpu(rec->e_cpos) +
 676                          le32_to_cpu(rec->e_clusters)) !=
 677                         (em->em_clusters + new_clusters),
 678                         "Inode %llu:\n"
 679                         "rec->e_cpos = %u + rec->e_clusters = %u = %u\n"
 680                         "em->em_clusters = %u + new_clusters = %u = %u\n",
 681                         (unsigned long long)OCFS2_I(inode)->ip_blkno,
 682                         le32_to_cpu(rec->e_cpos), le32_to_cpu(rec->e_clusters),
 683                         le32_to_cpu(rec->e_cpos) + le32_to_cpu(rec->e_clusters),
 684                         em->em_clusters, new_clusters,
 685                         em->em_clusters + new_clusters);
 686
 687         em->em_clusters += new_clusters;
 688
 689         ret = -ENOENT;
 690         if (le32_to_cpu(rec->e_clusters) > new_clusters) {
 691                 /* This is a contiguous append */
 692                 ent = ocfs2_extent_map_lookup(em, le32_to_cpu(rec->e_cpos), 1,
 693                                               NULL, NULL);
 694                 if (ent) {
 695                         old = &ent->e_rec;
 696                         BUG_ON((le32_to_cpu(rec->e_cpos) +
 697                                 le32_to_cpu(rec->e_clusters)) !=
 698                                  (le32_to_cpu(old->e_cpos) +
 699                                   le32_to_cpu(old->e_clusters) +
 700                                   new_clusters));
 701                         if (ent->e_tree_depth == 0) {
 702                                 BUG_ON(le32_to_cpu(old->e_cpos) !=
 703                                        le32_to_cpu(rec->e_cpos));
 704                                 BUG_ON(le64_to_cpu(old->e_blkno) !=
 705                                        le64_to_cpu(rec->e_blkno));
 706                                 ret = 0;
 707                         }
 708                         /*
 709                          * Let non-leafs fall through as -ENOENT to
 710                          * force insertion of the new leaf.
 711                          */
 712                         le32_add_cpu(&old->e_clusters, new_clusters);
 713                 }
 714         }
 715
 716         if (ret == -ENOENT)
 717                 ret = ocfs2_extent_map_insert(inode, rec, 0);
 718         if (ret < 0)
 719                 mlog_errno(ret);
 720         return ret;
 721 }
 722
 723 #if 0
 724 /* Code here is included but defined out as it completes the extent
 725  * map api and may be used in the future. */
 726
 727 /*
 728  * Look up the record containing this cluster offset.  This record is
 729  * part of the extent map.  Do not free it.  Any changes you make to
 730  * it will reflect in the extent map.  So, if your last extent
 731  * is (cpos = 10, clusters = 10) and you truncate the file by 5
 732  * clusters, you can do:
 733  *
 734  * ret = ocfs2_extent_map_get_rec(em, orig_size - 5, &rec);
 735  * rec->e_clusters -= 5;
 736  *
 737  * The lookup does not read from disk.  If the map isn't filled in for
 738  * an entry, you won't find it.
 739  *
 740  * Also note that the returned record is valid until alloc_sem is
 741  * dropped.  After that, truncate and extend can happen.  Caveat Emptor.
 742  */
 743 int ocfs2_extent_map_get_rec(struct inode *inode, u32 cpos,
 744                              struct ocfs2_extent_rec **rec,
 745                              int *tree_depth)
 746 {
 747         int ret = -ENOENT;
 748         struct ocfs2_extent_map *em = &OCFS2_I(inode)->ip_map;
 749         struct ocfs2_extent_map_entry *ent;
 750
 751         *rec = NULL;
 752
 753         if (cpos >= OCFS2_I(inode)->ip_clusters)
 754                 return -EINVAL;
 755
 756         if (cpos >= em->em_clusters) {
 757                 /*
 758                  * Size changed underneath us on disk.  Drop any
 759                  * straddling records and update our idea of
 760                  * i_clusters
 761                  */
 762                 ocfs2_extent_map_drop(inode, em->em_clusters - 1);
 763                 em->em_clusters = OCFS2_I(inode)->ip_clusters ;
 764         }
 765
 766         ent = ocfs2_extent_map_lookup(&OCFS2_I(inode)->ip_map, cpos, 1,
 767                                       NULL, NULL);
 768
 769         if (ent) {
 770                 *rec = &ent->e_rec;
 771                 if (tree_depth)
 772                         *tree_depth = ent->e_tree_depth;
 773                 ret = 0;
 774         }
 775
 776         return ret;
 777 }
 778
 779 int ocfs2_extent_map_get_clusters(struct inode *inode,
 780                                   u32 v_cpos, int count,
 781                                   u32 *p_cpos, int *ret_count)
 782 {
 783         int ret;
 784         u32 coff, ccount;
 785         struct ocfs2_extent_map *em = &OCFS2_I(inode)->ip_map;
 786         struct ocfs2_extent_map_entry *ent = NULL;
 787
 788         *p_cpos = ccount = 0;
 789
 790         if ((v_cpos + count) > OCFS2_I(inode)->ip_clusters)
 791                 return -EINVAL;
 792
 793         if ((v_cpos + count) > em->em_clusters) {
 794                 /*
 795                  * Size changed underneath us on disk.  Drop any
 796                  * straddling records and update our idea of
 797                  * i_clusters
 798                  */
 799                 ocfs2_extent_map_drop(inode, em->em_clusters - 1);
 800                 em->em_clusters = OCFS2_I(inode)->ip_clusters;
 801         }
 802
 803
 804         ret = ocfs2_extent_map_lookup_read(inode, v_cpos, count, &ent);
 805         if (ret)
 806                 return ret;
 807
 808         if (ent) {
 809                 /* We should never find ourselves straddling an interval */
 810                 if (!ocfs2_extent_rec_contains_clusters(&ent->e_rec,
 811                                                         v_cpos,
 812                                                         count))
 813                         return -ESRCH;
 814
 815                 coff = v_cpos - le32_to_cpu(ent->e_rec.e_cpos);
 816                 *p_cpos = ocfs2_blocks_to_clusters(inode->i_sb,
 817                                 le64_to_cpu(ent->e_rec.e_blkno)) +
 818                           coff;
 819
 820                 if (ret_count)
 821                         *ret_count = le32_to_cpu(ent->e_rec.e_clusters) - coff;
 822
 823                 return 0;
 824         }
 825
 826
 827         return -ENOENT;
 828 }
 829
 830 #endif  /*  0  */
 831
 832 int ocfs2_extent_map_get_blocks(struct inode *inode,
 833                                 u64 v_blkno, int count,
 834                                 u64 *p_blkno, int *ret_count)
 835 {
 836         int ret;
 837         u64 boff;
 838         u32 cpos, clusters;
 839         int bpc = ocfs2_clusters_to_blocks(inode->i_sb, 1);
 840         struct ocfs2_extent_map_entry *ent = NULL;
 841         struct ocfs2_extent_map *em = &OCFS2_I(inode)->ip_map;
 842         struct ocfs2_extent_rec *rec;
 843
 844         *p_blkno = 0;
 845
 846         cpos = ocfs2_blocks_to_clusters(inode->i_sb, v_blkno);
 847         clusters = ocfs2_blocks_to_clusters(inode->i_sb,
 848                                             (u64)count + bpc - 1);
 849         if ((cpos + clusters) > OCFS2_I(inode)->ip_clusters) {
 850                 ret = -EINVAL;
 851                 mlog_errno(ret);
 852                 return ret;
 853         }
 854
 855         if ((cpos + clusters) > em->em_clusters) {
 856                 /*
 857                  * Size changed underneath us on disk.  Drop any
 858                  * straddling records and update our idea of
 859                  * i_clusters
 860                  */
 861                 ocfs2_extent_map_drop(inode, em->em_clusters - 1);
 862                 em->em_clusters = OCFS2_I(inode)->ip_clusters;
 863         }
 864
 865         ret = ocfs2_extent_map_lookup_read(inode, cpos, clusters, &ent);
 866         if (ret) {
 867                 mlog_errno(ret);
 868                 return ret;
 869         }
 870
 871         if (ent)
 872         {
 873                 rec = &ent->e_rec;
 874
 875                 /* We should never find ourselves straddling an interval */
 876                 if (!ocfs2_extent_rec_contains_clusters(rec, cpos, clusters)) {
 877                         ret = -ESRCH;
 878                         mlog_errno(ret);
 879                         return ret;
 880                 }
 881
 882                 boff = ocfs2_clusters_to_blocks(inode->i_sb, cpos -
 883                                                 le32_to_cpu(rec->e_cpos));
 884                 boff += (v_blkno & (u64)(bpc - 1));
 885                 *p_blkno = le64_to_cpu(rec->e_blkno) + boff;
 886
 887                 if (ret_count) {
 888                         *ret_count = ocfs2_clusters_to_blocks(inode->i_sb,
 889                                         le32_to_cpu(rec->e_clusters)) - boff;
 890                 }
 891
 892                 return 0;
 893         }
 894
 895         return -ENOENT;
 896 }
 897
 898 int ocfs2_extent_map_init(struct inode *inode)
 899 {
 900         struct ocfs2_extent_map *em = &OCFS2_I(inode)->ip_map;
 901
 902         em->em_extents = RB_ROOT;
 903         em->em_clusters = 0;
 904
 905         return 0;
 906 }
 907
 908 /* Needs the lock */
 909 static void __ocfs2_extent_map_drop(struct inode *inode,
 910                                     u32 new_clusters,
 911                                     struct rb_node **free_head,
 912                                     struct ocfs2_extent_map_entry **tail_ent)
 913 {
 914         struct rb_node *node, *next;
 915         struct ocfs2_extent_map *em = &OCFS2_I(inode)->ip_map;
 916         struct ocfs2_extent_map_entry *ent;
 917
 918         *free_head = NULL;
 919
 920         ent = NULL;
 921         node = rb_last(&em->em_extents);
 922         while (node)
 923         {
 924                 next = rb_prev(node);
 925
 926                 ent = rb_entry(node, struct ocfs2_extent_map_entry,
 927                                e_node);
 928                 if (le32_to_cpu(ent->e_rec.e_cpos) < new_clusters)
 929                         break;
 930
 931                 rb_erase(&ent->e_node, &em->em_extents);
 932
 933                 node->rb_right = *free_head;
 934                 *free_head = node;
 935
 936                 ent = NULL;
 937                 node = next;
 938         }
 939
 940         /* Do we have an entry straddling new_clusters? */
 941         if (tail_ent) {
 942                 if (ent &&
 943                     ((le32_to_cpu(ent->e_rec.e_cpos) +
 944                       le32_to_cpu(ent->e_rec.e_clusters)) > new_clusters))
 945                         *tail_ent = ent;
 946                 else
 947                         *tail_ent = NULL;
 948         }
 949 }
 950
 951 static void __ocfs2_extent_map_drop_cleanup(struct rb_node *free_head)
 952 {
 953         struct rb_node *node;
 954         struct ocfs2_extent_map_entry *ent;
 955
 956         while (free_head) {
 957                 node = free_head;
 958                 free_head = node->rb_right;
 959
 960                 ent = rb_entry(node, struct ocfs2_extent_map_entry,
 961                                e_node);
 962                 kmem_cache_free(ocfs2_em_ent_cachep, ent);
 963         }
 964 }
 965
 966 /*
 967  * Remove all entries past new_clusters, inclusive of an entry that
 968  * contains new_clusters.  This is effectively a cache forget.
 969  *
 970  * If you want to also clip the last extent by some number of clusters,
 971  * you need to call ocfs2_extent_map_trunc().
 972  * This code does not check or modify ip_clusters.
 973  */
 974 int ocfs2_extent_map_drop(struct inode *inode, u32 new_clusters)
 975 {
 976         struct rb_node *free_head = NULL;
 977         struct ocfs2_extent_map *em = &OCFS2_I(inode)->ip_map;
 978         struct ocfs2_extent_map_entry *ent;
 979
 980         spin_lock(&OCFS2_I(inode)->ip_lock);
 981
 982         __ocfs2_extent_map_drop(inode, new_clusters, &free_head, &ent);
 983
 984         if (ent) {
 985                 rb_erase(&ent->e_node, &em->em_extents);
 986                 ent->e_node.rb_right = free_head;
 987                 free_head = &ent->e_node;
 988         }
 989
 990         spin_unlock(&OCFS2_I(inode)->ip_lock);
 991
 992         if (free_head)
 993                 __ocfs2_extent_map_drop_cleanup(free_head);
 994
 995         return 0;
 996 }
 997
 998 /*
 999  * Remove all entries past new_clusters and also clip any extent
1000  * straddling new_clusters, if there is one.  This does not check
1001  * or modify ip_clusters
1002  */
1003 int ocfs2_extent_map_trunc(struct inode *inode, u32 new_clusters)
1004 {
1005         struct rb_node *free_head = NULL;
1006         struct ocfs2_extent_map_entry *ent = NULL;
1007
1008         spin_lock(&OCFS2_I(inode)->ip_lock);
1009
1010         __ocfs2_extent_map_drop(inode, new_clusters, &free_head, &ent);
1011
1012         if (ent)
1013                 ent->e_rec.e_clusters = cpu_to_le32(new_clusters -
1014                                                le32_to_cpu(ent->e_rec.e_cpos));
1015
1016         OCFS2_I(inode)->ip_map.em_clusters = new_clusters;
1017
1018         spin_unlock(&OCFS2_I(inode)->ip_lock);
1019
1020         if (free_head)
1021                 __ocfs2_extent_map_drop_cleanup(free_head);
1022
1023         return 0;
1024 }
1025
1026 int __init init_ocfs2_extent_maps(void)
1027 {
1028         ocfs2_em_ent_cachep =
1029                 kmem_cache_create("ocfs2_em_ent",
1030                                   sizeof(struct ocfs2_extent_map_entry),
1031                                   0, SLAB_HWCACHE_ALIGN, NULL, NULL);
1032         if (!ocfs2_em_ent_cachep)
1033                 return -ENOMEM;
1034
1035         return 0;
1036 }
1037
1038 void exit_ocfs2_extent_maps(void)
1039 {
1040         kmem_cache_destroy(ocfs2_em_ent_cachep);
1041 }