SAFE public projects git trees. - safe/jmp/linux-2.6/blob - fs/ext4/extents.c

   1 /*
   2  * Copyright (c) 2003-2006, Cluster File Systems, Inc, info@clusterfs.com
   3  * Written by Alex Tomas <alex@clusterfs.com>
   4  *
   5  * Architecture independence:
   6  *   Copyright (c) 2005, Bull S.A.
   7  *   Written by Pierre Peiffer <pierre.peiffer@bull.net>
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License version 2 as
  11  * published by the Free Software Foundation.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  * GNU General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public Licens
  19  * along with this program; if not, write to the Free Software
  20  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-
  21  */
  22
  23 /*
  24  * Extents support for EXT4
  25  *
  26  * TODO:
  27  *   - ext4*_error() should be used in some situations
  28  *   - analyze all BUG()/BUG_ON(), use -EIO where appropriate
  29  *   - smart tree reduction
  30  */
  31
  32 #include <linux/module.h>
  33 #include <linux/fs.h>
  34 #include <linux/time.h>
  35 #include <linux/ext4_jbd2.h>
  36 #include <linux/jbd.h>
  37 #include <linux/smp_lock.h>
  38 #include <linux/highuid.h>
  39 #include <linux/pagemap.h>
  40 #include <linux/quotaops.h>
  41 #include <linux/string.h>
  42 #include <linux/slab.h>
  43 #include <linux/ext4_fs_extents.h>
  44 #include <asm/uaccess.h>
  45
  46
  47 /*
  48  * ext_pblock:
  49  * combine low and high parts of physical block number into ext4_fsblk_t
  50  */
  51 static inline ext4_fsblk_t ext_pblock(struct ext4_extent *ex)
  52 {
  53         ext4_fsblk_t block;
  54
  55         block = le32_to_cpu(ex->ee_start);
  56         if (sizeof(ext4_fsblk_t) > 4)
  57                 block |= ((ext4_fsblk_t) le16_to_cpu(ex->ee_start_hi) << 31) << 1;
  58         return block;
  59 }
  60
  61 /*
  62  * idx_pblock:
  63  * combine low and high parts of a leaf physical block number into ext4_fsblk_t
  64  */
  65 static inline ext4_fsblk_t idx_pblock(struct ext4_extent_idx *ix)
  66 {
  67         ext4_fsblk_t block;
  68
  69         block = le32_to_cpu(ix->ei_leaf);
  70         if (sizeof(ext4_fsblk_t) > 4)
  71                 block |= ((ext4_fsblk_t) le16_to_cpu(ix->ei_leaf_hi) << 31) << 1;
  72         return block;
  73 }
  74
  75 /*
  76  * ext4_ext_store_pblock:
  77  * stores a large physical block number into an extent struct,
  78  * breaking it into parts
  79  */
  80 static inline void ext4_ext_store_pblock(struct ext4_extent *ex, ext4_fsblk_t pb)
  81 {
  82         ex->ee_start = cpu_to_le32((unsigned long) (pb & 0xffffffff));
  83         if (sizeof(ext4_fsblk_t) > 4)
  84                 ex->ee_start_hi = cpu_to_le16((unsigned long) ((pb >> 31) >> 1) & 0xffff);
  85 }
  86
  87 /*
  88  * ext4_idx_store_pblock:
  89  * stores a large physical block number into an index struct,
  90  * breaking it into parts
  91  */
  92 static inline void ext4_idx_store_pblock(struct ext4_extent_idx *ix, ext4_fsblk_t pb)
  93 {
  94         ix->ei_leaf = cpu_to_le32((unsigned long) (pb & 0xffffffff));
  95         if (sizeof(ext4_fsblk_t) > 4)
  96                 ix->ei_leaf_hi = cpu_to_le16((unsigned long) ((pb >> 31) >> 1) & 0xffff);
  97 }
  98
  99 static int ext4_ext_check_header(const char *function, struct inode *inode,
 100                                 struct ext4_extent_header *eh)
 101 {
 102         const char *error_msg = NULL;
 103
 104         if (unlikely(eh->eh_magic != EXT4_EXT_MAGIC)) {
 105                 error_msg = "invalid magic";
 106                 goto corrupted;
 107         }
 108         if (unlikely(eh->eh_max == 0)) {
 109                 error_msg = "invalid eh_max";
 110                 goto corrupted;
 111         }
 112         if (unlikely(le16_to_cpu(eh->eh_entries) > le16_to_cpu(eh->eh_max))) {
 113                 error_msg = "invalid eh_entries";
 114                 goto corrupted;
 115         }
 116         return 0;
 117
 118 corrupted:
 119         ext4_error(inode->i_sb, function,
 120                         "bad header in inode #%lu: %s - magic %x, "
 121                         "entries %u, max %u, depth %u",
 122                         inode->i_ino, error_msg, le16_to_cpu(eh->eh_magic),
 123                         le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max),
 124                         le16_to_cpu(eh->eh_depth));
 125
 126         return -EIO;
 127 }
 128
 129 static handle_t *ext4_ext_journal_restart(handle_t *handle, int needed)
 130 {
 131         int err;
 132
 133         if (handle->h_buffer_credits > needed)
 134                 return handle;
 135         if (!ext4_journal_extend(handle, needed))
 136                 return handle;
 137         err = ext4_journal_restart(handle, needed);
 138
 139         return handle;
 140 }
 141
 142 /*
 143  * could return:
 144  *  - EROFS
 145  *  - ENOMEM
 146  */
 147 static int ext4_ext_get_access(handle_t *handle, struct inode *inode,
 148                                 struct ext4_ext_path *path)
 149 {
 150         if (path->p_bh) {
 151                 /* path points to block */
 152                 return ext4_journal_get_write_access(handle, path->p_bh);
 153         }
 154         /* path points to leaf/index in inode body */
 155         /* we use in-core data, no need to protect them */
 156         return 0;
 157 }
 158
 159 /*
 160  * could return:
 161  *  - EROFS
 162  *  - ENOMEM
 163  *  - EIO
 164  */
 165 static int ext4_ext_dirty(handle_t *handle, struct inode *inode,
 166                                 struct ext4_ext_path *path)
 167 {
 168         int err;
 169         if (path->p_bh) {
 170                 /* path points to block */
 171                 err = ext4_journal_dirty_metadata(handle, path->p_bh);
 172         } else {
 173                 /* path points to leaf/index in inode body */
 174                 err = ext4_mark_inode_dirty(handle, inode);
 175         }
 176         return err;
 177 }
 178
 179 static ext4_fsblk_t ext4_ext_find_goal(struct inode *inode,
 180                               struct ext4_ext_path *path,
 181                               ext4_fsblk_t block)
 182 {
 183         struct ext4_inode_info *ei = EXT4_I(inode);
 184         ext4_fsblk_t bg_start;
 185         ext4_grpblk_t colour;
 186         int depth;
 187
 188         if (path) {
 189                 struct ext4_extent *ex;
 190                 depth = path->p_depth;
 191
 192                 /* try to predict block placement */
 193                 if ((ex = path[depth].p_ext))
 194                         return ext_pblock(ex)+(block-le32_to_cpu(ex->ee_block));
 195
 196                 /* it looks like index is empty;
 197                  * try to find starting block from index itself */
 198                 if (path[depth].p_bh)
 199                         return path[depth].p_bh->b_blocknr;
 200         }
 201
 202         /* OK. use inode's group */
 203         bg_start = (ei->i_block_group * EXT4_BLOCKS_PER_GROUP(inode->i_sb)) +
 204                 le32_to_cpu(EXT4_SB(inode->i_sb)->s_es->s_first_data_block);
 205         colour = (current->pid % 16) *
 206                         (EXT4_BLOCKS_PER_GROUP(inode->i_sb) / 16);
 207         return bg_start + colour + block;
 208 }
 209
 210 static ext4_fsblk_t
 211 ext4_ext_new_block(handle_t *handle, struct inode *inode,
 212                         struct ext4_ext_path *path,
 213                         struct ext4_extent *ex, int *err)
 214 {
 215         ext4_fsblk_t goal, newblock;
 216
 217         goal = ext4_ext_find_goal(inode, path, le32_to_cpu(ex->ee_block));
 218         newblock = ext4_new_block(handle, inode, goal, err);
 219         return newblock;
 220 }
 221
 222 static inline int ext4_ext_space_block(struct inode *inode)
 223 {
 224         int size;
 225
 226         size = (inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header))
 227                         / sizeof(struct ext4_extent);
 228 #ifdef AGRESSIVE_TEST
 229         if (size > 6)
 230                 size = 6;
 231 #endif
 232         return size;
 233 }
 234
 235 static inline int ext4_ext_space_block_idx(struct inode *inode)
 236 {
 237         int size;
 238
 239         size = (inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header))
 240                         / sizeof(struct ext4_extent_idx);
 241 #ifdef AGRESSIVE_TEST
 242         if (size > 5)
 243                 size = 5;
 244 #endif
 245         return size;
 246 }
 247
 248 static inline int ext4_ext_space_root(struct inode *inode)
 249 {
 250         int size;
 251
 252         size = sizeof(EXT4_I(inode)->i_data);
 253         size -= sizeof(struct ext4_extent_header);
 254         size /= sizeof(struct ext4_extent);
 255 #ifdef AGRESSIVE_TEST
 256         if (size > 3)
 257                 size = 3;
 258 #endif
 259         return size;
 260 }
 261
 262 static inline int ext4_ext_space_root_idx(struct inode *inode)
 263 {
 264         int size;
 265
 266         size = sizeof(EXT4_I(inode)->i_data);
 267         size -= sizeof(struct ext4_extent_header);
 268         size /= sizeof(struct ext4_extent_idx);
 269 #ifdef AGRESSIVE_TEST
 270         if (size > 4)
 271                 size = 4;
 272 #endif
 273         return size;
 274 }
 275
 276 #ifdef EXT_DEBUG
 277 static void ext4_ext_show_path(struct inode *inode, struct ext4_ext_path *path)
 278 {
 279         int k, l = path->p_depth;
 280
 281         ext_debug("path:");
 282         for (k = 0; k <= l; k++, path++) {
 283                 if (path->p_idx) {
 284                   ext_debug("  %d->"E3FSBLK, le32_to_cpu(path->p_idx->ei_block),
 285                             idx_pblock(path->p_idx));
 286                 } else if (path->p_ext) {
 287                         ext_debug("  %d:%d:"E3FSBLK" ",
 288                                   le32_to_cpu(path->p_ext->ee_block),
 289                                   le16_to_cpu(path->p_ext->ee_len),
 290                                   ext_pblock(path->p_ext));
 291                 } else
 292                         ext_debug("  []");
 293         }
 294         ext_debug("\n");
 295 }
 296
 297 static void ext4_ext_show_leaf(struct inode *inode, struct ext4_ext_path *path)
 298 {
 299         int depth = ext_depth(inode);
 300         struct ext4_extent_header *eh;
 301         struct ext4_extent *ex;
 302         int i;
 303
 304         if (!path)
 305                 return;
 306
 307         eh = path[depth].p_hdr;
 308         ex = EXT_FIRST_EXTENT(eh);
 309
 310         for (i = 0; i < le16_to_cpu(eh->eh_entries); i++, ex++) {
 311                 ext_debug("%d:%d:"E3FSBLK" ", le32_to_cpu(ex->ee_block),
 312                           le16_to_cpu(ex->ee_len), ext_pblock(ex));
 313         }
 314         ext_debug("\n");
 315 }
 316 #else
 317 #define ext4_ext_show_path(inode,path)
 318 #define ext4_ext_show_leaf(inode,path)
 319 #endif
 320
 321 static void ext4_ext_drop_refs(struct ext4_ext_path *path)
 322 {
 323         int depth = path->p_depth;
 324         int i;
 325
 326         for (i = 0; i <= depth; i++, path++)
 327                 if (path->p_bh) {
 328                         brelse(path->p_bh);
 329                         path->p_bh = NULL;
 330                 }
 331 }
 332
 333 /*
 334  * ext4_ext_binsearch_idx:
 335  * binary search for the closest index of the given block
 336  */
 337 static void
 338 ext4_ext_binsearch_idx(struct inode *inode, struct ext4_ext_path *path, int block)
 339 {
 340         struct ext4_extent_header *eh = path->p_hdr;
 341         struct ext4_extent_idx *r, *l, *m;
 342
 343         BUG_ON(eh->eh_magic != EXT4_EXT_MAGIC);
 344         BUG_ON(le16_to_cpu(eh->eh_entries) > le16_to_cpu(eh->eh_max));
 345         BUG_ON(le16_to_cpu(eh->eh_entries) <= 0);
 346
 347         ext_debug("binsearch for %d(idx):  ", block);
 348
 349         l = EXT_FIRST_INDEX(eh) + 1;
 350         r = EXT_FIRST_INDEX(eh) + le16_to_cpu(eh->eh_entries) - 1;
 351         while (l <= r) {
 352                 m = l + (r - l) / 2;
 353                 if (block < le32_to_cpu(m->ei_block))
 354                         r = m - 1;
 355                 else
 356                         l = m + 1;
 357                 ext_debug("%p(%u):%p(%u):%p(%u) ", l, l->ei_block,
 358                                 m, m->ei_block, r, r->ei_block);
 359         }
 360
 361         path->p_idx = l - 1;
 362         ext_debug("  -> %d->%lld ", le32_to_cpu(path->p_idx->ei_block),
 363                   idx_block(path->p_idx));
 364
 365 #ifdef CHECK_BINSEARCH
 366         {
 367                 struct ext4_extent_idx *chix, *ix;
 368                 int k;
 369
 370                 chix = ix = EXT_FIRST_INDEX(eh);
 371                 for (k = 0; k < le16_to_cpu(eh->eh_entries); k++, ix++) {
 372                   if (k != 0 &&
 373                       le32_to_cpu(ix->ei_block) <= le32_to_cpu(ix[-1].ei_block)) {
 374                                 printk("k=%d, ix=0x%p, first=0x%p\n", k,
 375                                         ix, EXT_FIRST_INDEX(eh));
 376                                 printk("%u <= %u\n",
 377                                        le32_to_cpu(ix->ei_block),
 378                                        le32_to_cpu(ix[-1].ei_block));
 379                         }
 380                         BUG_ON(k && le32_to_cpu(ix->ei_block)
 381                                            <= le32_to_cpu(ix[-1].ei_block));
 382                         if (block < le32_to_cpu(ix->ei_block))
 383                                 break;
 384                         chix = ix;
 385                 }
 386                 BUG_ON(chix != path->p_idx);
 387         }
 388 #endif
 389
 390 }
 391
 392 /*
 393  * ext4_ext_binsearch:
 394  * binary search for closest extent of the given block
 395  */
 396 static void
 397 ext4_ext_binsearch(struct inode *inode, struct ext4_ext_path *path, int block)
 398 {
 399         struct ext4_extent_header *eh = path->p_hdr;
 400         struct ext4_extent *r, *l, *m;
 401
 402         BUG_ON(eh->eh_magic != EXT4_EXT_MAGIC);
 403         BUG_ON(le16_to_cpu(eh->eh_entries) > le16_to_cpu(eh->eh_max));
 404
 405         if (eh->eh_entries == 0) {
 406                 /*
 407                  * this leaf is empty:
 408                  * we get such a leaf in split/add case
 409                  */
 410                 return;
 411         }
 412
 413         ext_debug("binsearch for %d:  ", block);
 414
 415         l = EXT_FIRST_EXTENT(eh) + 1;
 416         r = EXT_FIRST_EXTENT(eh) + le16_to_cpu(eh->eh_entries) - 1;
 417
 418         while (l <= r) {
 419                 m = l + (r - l) / 2;
 420                 if (block < le32_to_cpu(m->ee_block))
 421                         r = m - 1;
 422                 else
 423                         l = m + 1;
 424                 ext_debug("%p(%u):%p(%u):%p(%u) ", l, l->ee_block,
 425                                 m, m->ee_block, r, r->ee_block);
 426         }
 427
 428         path->p_ext = l - 1;
 429         ext_debug("  -> %d:"E3FSBLK":%d ",
 430                         le32_to_cpu(path->p_ext->ee_block),
 431                         ext_pblock(path->p_ext),
 432                         le16_to_cpu(path->p_ext->ee_len));
 433
 434 #ifdef CHECK_BINSEARCH
 435         {
 436                 struct ext4_extent *chex, *ex;
 437                 int k;
 438
 439                 chex = ex = EXT_FIRST_EXTENT(eh);
 440                 for (k = 0; k < le16_to_cpu(eh->eh_entries); k++, ex++) {
 441                         BUG_ON(k && le32_to_cpu(ex->ee_block)
 442                                           <= le32_to_cpu(ex[-1].ee_block));
 443                         if (block < le32_to_cpu(ex->ee_block))
 444                                 break;
 445                         chex = ex;
 446                 }
 447                 BUG_ON(chex != path->p_ext);
 448         }
 449 #endif
 450
 451 }
 452
 453 int ext4_ext_tree_init(handle_t *handle, struct inode *inode)
 454 {
 455         struct ext4_extent_header *eh;
 456
 457         eh = ext_inode_hdr(inode);
 458         eh->eh_depth = 0;
 459         eh->eh_entries = 0;
 460         eh->eh_magic = EXT4_EXT_MAGIC;
 461         eh->eh_max = cpu_to_le16(ext4_ext_space_root(inode));
 462         ext4_mark_inode_dirty(handle, inode);
 463         ext4_ext_invalidate_cache(inode);
 464         return 0;
 465 }
 466
 467 struct ext4_ext_path *
 468 ext4_ext_find_extent(struct inode *inode, int block, struct ext4_ext_path *path)
 469 {
 470         struct ext4_extent_header *eh;
 471         struct buffer_head *bh;
 472         short int depth, i, ppos = 0, alloc = 0;
 473
 474         eh = ext_inode_hdr(inode);
 475         BUG_ON(eh == NULL);
 476         if (ext4_ext_check_header(__FUNCTION__, inode, eh))
 477                 return ERR_PTR(-EIO);
 478
 479         i = depth = ext_depth(inode);
 480
 481         /* account possible depth increase */
 482         if (!path) {
 483                 path = kmalloc(sizeof(struct ext4_ext_path) * (depth + 2),
 484                                 GFP_NOFS);
 485                 if (!path)
 486                         return ERR_PTR(-ENOMEM);
 487                 alloc = 1;
 488         }
 489         memset(path, 0, sizeof(struct ext4_ext_path) * (depth + 1));
 490         path[0].p_hdr = eh;
 491
 492         /* walk through the tree */
 493         while (i) {
 494                 ext_debug("depth %d: num %d, max %d\n",
 495                           ppos, le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max));
 496                 ext4_ext_binsearch_idx(inode, path + ppos, block);
 497                 path[ppos].p_block = idx_pblock(path[ppos].p_idx);
 498                 path[ppos].p_depth = i;
 499                 path[ppos].p_ext = NULL;
 500
 501                 bh = sb_bread(inode->i_sb, path[ppos].p_block);
 502                 if (!bh)
 503                         goto err;
 504
 505                 eh = ext_block_hdr(bh);
 506                 ppos++;
 507                 BUG_ON(ppos > depth);
 508                 path[ppos].p_bh = bh;
 509                 path[ppos].p_hdr = eh;
 510                 i--;
 511
 512                 if (ext4_ext_check_header(__FUNCTION__, inode, eh))
 513                         goto err;
 514         }
 515
 516         path[ppos].p_depth = i;
 517         path[ppos].p_hdr = eh;
 518         path[ppos].p_ext = NULL;
 519         path[ppos].p_idx = NULL;
 520
 521         if (ext4_ext_check_header(__FUNCTION__, inode, eh))
 522                 goto err;
 523
 524         /* find extent */
 525         ext4_ext_binsearch(inode, path + ppos, block);
 526
 527         ext4_ext_show_path(inode, path);
 528
 529         return path;
 530
 531 err:
 532         ext4_ext_drop_refs(path);
 533         if (alloc)
 534                 kfree(path);
 535         return ERR_PTR(-EIO);
 536 }
 537
 538 /*
 539  * ext4_ext_insert_index:
 540  * insert new index [@logical;@ptr] into the block at @curp;
 541  * check where to insert: before @curp or after @curp
 542  */
 543 static int ext4_ext_insert_index(handle_t *handle, struct inode *inode,
 544                                 struct ext4_ext_path *curp,
 545                                 int logical, ext4_fsblk_t ptr)
 546 {
 547         struct ext4_extent_idx *ix;
 548         int len, err;
 549
 550         if ((err = ext4_ext_get_access(handle, inode, curp)))
 551                 return err;
 552
 553         BUG_ON(logical == le32_to_cpu(curp->p_idx->ei_block));
 554         len = EXT_MAX_INDEX(curp->p_hdr) - curp->p_idx;
 555         if (logical > le32_to_cpu(curp->p_idx->ei_block)) {
 556                 /* insert after */
 557                 if (curp->p_idx != EXT_LAST_INDEX(curp->p_hdr)) {
 558                         len = (len - 1) * sizeof(struct ext4_extent_idx);
 559                         len = len < 0 ? 0 : len;
 560                         ext_debug("insert new index %d after: %d. "
 561                                         "move %d from 0x%p to 0x%p\n",
 562                                         logical, ptr, len,
 563                                         (curp->p_idx + 1), (curp->p_idx + 2));
 564                         memmove(curp->p_idx + 2, curp->p_idx + 1, len);
 565                 }
 566                 ix = curp->p_idx + 1;
 567         } else {
 568                 /* insert before */
 569                 len = len * sizeof(struct ext4_extent_idx);
 570                 len = len < 0 ? 0 : len;
 571                 ext_debug("insert new index %d before: %d. "
 572                                 "move %d from 0x%p to 0x%p\n",
 573                                 logical, ptr, len,
 574                                 curp->p_idx, (curp->p_idx + 1));
 575                 memmove(curp->p_idx + 1, curp->p_idx, len);
 576                 ix = curp->p_idx;
 577         }
 578
 579         ix->ei_block = cpu_to_le32(logical);
 580         ext4_idx_store_pblock(ix, ptr);
 581         curp->p_hdr->eh_entries = cpu_to_le16(le16_to_cpu(curp->p_hdr->eh_entries)+1);
 582
 583         BUG_ON(le16_to_cpu(curp->p_hdr->eh_entries)
 584                              > le16_to_cpu(curp->p_hdr->eh_max));
 585         BUG_ON(ix > EXT_LAST_INDEX(curp->p_hdr));
 586
 587         err = ext4_ext_dirty(handle, inode, curp);
 588         ext4_std_error(inode->i_sb, err);
 589
 590         return err;
 591 }
 592
 593 /*
 594  * ext4_ext_split:
 595  * inserts new subtree into the path, using free index entry
 596  * at depth @at:
 597  * - allocates all needed blocks (new leaf and all intermediate index blocks)
 598  * - makes decision where to split
 599  * - moves remaining extents and index entries (right to the split point)
 600  *   into the newly allocated blocks
 601  * - initializes subtree
 602  */
 603 static int ext4_ext_split(handle_t *handle, struct inode *inode,
 604                                 struct ext4_ext_path *path,
 605                                 struct ext4_extent *newext, int at)
 606 {
 607         struct buffer_head *bh = NULL;
 608         int depth = ext_depth(inode);
 609         struct ext4_extent_header *neh;
 610         struct ext4_extent_idx *fidx;
 611         struct ext4_extent *ex;
 612         int i = at, k, m, a;
 613         ext4_fsblk_t newblock, oldblock;
 614         __le32 border;
 615         ext4_fsblk_t *ablocks = NULL; /* array of allocated blocks */
 616         int err = 0;
 617
 618         /* make decision: where to split? */
 619         /* FIXME: now decision is simplest: at current extent */
 620
 621         /* if current leaf will be split, then we should use
 622          * border from split point */
 623         BUG_ON(path[depth].p_ext > EXT_MAX_EXTENT(path[depth].p_hdr));
 624         if (path[depth].p_ext != EXT_MAX_EXTENT(path[depth].p_hdr)) {
 625                 border = path[depth].p_ext[1].ee_block;
 626                 ext_debug("leaf will be split."
 627                                 " next leaf starts at %d\n",
 628                                   le32_to_cpu(border));
 629         } else {
 630                 border = newext->ee_block;
 631                 ext_debug("leaf will be added."
 632                                 " next leaf starts at %d\n",
 633                                 le32_to_cpu(border));
 634         }
 635
 636         /*
 637          * If error occurs, then we break processing
 638          * and mark filesystem read-only. index won't
 639          * be inserted and tree will be in consistent
 640          * state. Next mount will repair buffers too.
 641          */
 642
 643         /*
 644          * Get array to track all allocated blocks.
 645          * We need this to handle errors and free blocks
 646          * upon them.
 647          */
 648         ablocks = kmalloc(sizeof(ext4_fsblk_t) * depth, GFP_NOFS);
 649         if (!ablocks)
 650                 return -ENOMEM;
 651         memset(ablocks, 0, sizeof(ext4_fsblk_t) * depth);
 652
 653         /* allocate all needed blocks */
 654         ext_debug("allocate %d blocks for indexes/leaf\n", depth - at);
 655         for (a = 0; a < depth - at; a++) {
 656                 newblock = ext4_ext_new_block(handle, inode, path, newext, &err);
 657                 if (newblock == 0)
 658                         goto cleanup;
 659                 ablocks[a] = newblock;
 660         }
 661
 662         /* initialize new leaf */
 663         newblock = ablocks[--a];
 664         BUG_ON(newblock == 0);
 665         bh = sb_getblk(inode->i_sb, newblock);
 666         if (!bh) {
 667                 err = -EIO;
 668                 goto cleanup;
 669         }
 670         lock_buffer(bh);
 671
 672         if ((err = ext4_journal_get_create_access(handle, bh)))
 673                 goto cleanup;
 674
 675         neh = ext_block_hdr(bh);
 676         neh->eh_entries = 0;
 677         neh->eh_max = cpu_to_le16(ext4_ext_space_block(inode));
 678         neh->eh_magic = EXT4_EXT_MAGIC;
 679         neh->eh_depth = 0;
 680         ex = EXT_FIRST_EXTENT(neh);
 681
 682         /* move remainder of path[depth] to the new leaf */
 683         BUG_ON(path[depth].p_hdr->eh_entries != path[depth].p_hdr->eh_max);
 684         /* start copy from next extent */
 685         /* TODO: we could do it by single memmove */
 686         m = 0;
 687         path[depth].p_ext++;
 688         while (path[depth].p_ext <=
 689                         EXT_MAX_EXTENT(path[depth].p_hdr)) {
 690                 ext_debug("move %d:"E3FSBLK":%d in new leaf "E3FSBLK"\n",
 691                                 le32_to_cpu(path[depth].p_ext->ee_block),
 692                                 ext_pblock(path[depth].p_ext),
 693                                 le16_to_cpu(path[depth].p_ext->ee_len),
 694                                 newblock);
 695                 /*memmove(ex++, path[depth].p_ext++,
 696                                 sizeof(struct ext4_extent));
 697                 neh->eh_entries++;*/
 698                 path[depth].p_ext++;
 699                 m++;
 700         }
 701         if (m) {
 702                 memmove(ex, path[depth].p_ext-m, sizeof(struct ext4_extent)*m);
 703                 neh->eh_entries = cpu_to_le16(le16_to_cpu(neh->eh_entries)+m);
 704         }
 705
 706         set_buffer_uptodate(bh);
 707         unlock_buffer(bh);
 708
 709         if ((err = ext4_journal_dirty_metadata(handle, bh)))
 710                 goto cleanup;
 711         brelse(bh);
 712         bh = NULL;
 713
 714         /* correct old leaf */
 715         if (m) {
 716                 if ((err = ext4_ext_get_access(handle, inode, path + depth)))
 717                         goto cleanup;
 718                 path[depth].p_hdr->eh_entries =
 719                      cpu_to_le16(le16_to_cpu(path[depth].p_hdr->eh_entries)-m);
 720                 if ((err = ext4_ext_dirty(handle, inode, path + depth)))
 721                         goto cleanup;
 722
 723         }
 724
 725         /* create intermediate indexes */
 726         k = depth - at - 1;
 727         BUG_ON(k < 0);
 728         if (k)
 729                 ext_debug("create %d intermediate indices\n", k);
 730         /* insert new index into current index block */
 731         /* current depth stored in i var */
 732         i = depth - 1;
 733         while (k--) {
 734                 oldblock = newblock;
 735                 newblock = ablocks[--a];
 736                 bh = sb_getblk(inode->i_sb, (ext4_fsblk_t)newblock);
 737                 if (!bh) {
 738                         err = -EIO;
 739                         goto cleanup;
 740                 }
 741                 lock_buffer(bh);
 742
 743                 if ((err = ext4_journal_get_create_access(handle, bh)))
 744                         goto cleanup;
 745
 746                 neh = ext_block_hdr(bh);
 747                 neh->eh_entries = cpu_to_le16(1);
 748                 neh->eh_magic = EXT4_EXT_MAGIC;
 749                 neh->eh_max = cpu_to_le16(ext4_ext_space_block_idx(inode));
 750                 neh->eh_depth = cpu_to_le16(depth - i);
 751                 fidx = EXT_FIRST_INDEX(neh);
 752                 fidx->ei_block = border;
 753                 ext4_idx_store_pblock(fidx, oldblock);
 754
 755                 ext_debug("int.index at %d (block "E3FSBLK"): %lu -> "E3FSBLK"\n", i,
 756                                 newblock, (unsigned long) le32_to_cpu(border),
 757                                 oldblock);
 758                 /* copy indexes */
 759                 m = 0;
 760                 path[i].p_idx++;
 761
 762                 ext_debug("cur 0x%p, last 0x%p\n", path[i].p_idx,
 763                                 EXT_MAX_INDEX(path[i].p_hdr));
 764                 BUG_ON(EXT_MAX_INDEX(path[i].p_hdr) !=
 765                                 EXT_LAST_INDEX(path[i].p_hdr));
 766                 while (path[i].p_idx <= EXT_MAX_INDEX(path[i].p_hdr)) {
 767                         ext_debug("%d: move %d:%d in new index "E3FSBLK"\n", i,
 768                                         le32_to_cpu(path[i].p_idx->ei_block),
 769                                         idx_pblock(path[i].p_idx),
 770                                         newblock);
 771                         /*memmove(++fidx, path[i].p_idx++,
 772                                         sizeof(struct ext4_extent_idx));
 773                         neh->eh_entries++;
 774                         BUG_ON(neh->eh_entries > neh->eh_max);*/
 775                         path[i].p_idx++;
 776                         m++;
 777                 }
 778                 if (m) {
 779                         memmove(++fidx, path[i].p_idx - m,
 780                                 sizeof(struct ext4_extent_idx) * m);
 781                         neh->eh_entries =
 782                                 cpu_to_le16(le16_to_cpu(neh->eh_entries) + m);
 783                 }
 784                 set_buffer_uptodate(bh);
 785                 unlock_buffer(bh);
 786
 787                 if ((err = ext4_journal_dirty_metadata(handle, bh)))
 788                         goto cleanup;
 789                 brelse(bh);
 790                 bh = NULL;
 791
 792                 /* correct old index */
 793                 if (m) {
 794                         err = ext4_ext_get_access(handle, inode, path + i);
 795                         if (err)
 796                                 goto cleanup;
 797                         path[i].p_hdr->eh_entries = cpu_to_le16(le16_to_cpu(path[i].p_hdr->eh_entries)-m);
 798                         err = ext4_ext_dirty(handle, inode, path + i);
 799                         if (err)
 800                                 goto cleanup;
 801                 }
 802
 803                 i--;
 804         }
 805
 806         /* insert new index */
 807         if (err)
 808                 goto cleanup;
 809
 810         err = ext4_ext_insert_index(handle, inode, path + at,
 811                                     le32_to_cpu(border), newblock);
 812
 813 cleanup:
 814         if (bh) {
 815                 if (buffer_locked(bh))
 816                         unlock_buffer(bh);
 817                 brelse(bh);
 818         }
 819
 820         if (err) {
 821                 /* free all allocated blocks in error case */
 822                 for (i = 0; i < depth; i++) {
 823                         if (!ablocks[i])
 824                                 continue;
 825                         ext4_free_blocks(handle, inode, ablocks[i], 1);
 826                 }
 827         }
 828         kfree(ablocks);
 829
 830         return err;
 831 }
 832
 833 /*
 834  * ext4_ext_grow_indepth:
 835  * implements tree growing procedure:
 836  * - allocates new block
 837  * - moves top-level data (index block or leaf) into the new block
 838  * - initializes new top-level, creating index that points to the
 839  *   just created block
 840  */
 841 static int ext4_ext_grow_indepth(handle_t *handle, struct inode *inode,
 842                                         struct ext4_ext_path *path,
 843                                         struct ext4_extent *newext)
 844 {
 845         struct ext4_ext_path *curp = path;
 846         struct ext4_extent_header *neh;
 847         struct ext4_extent_idx *fidx;
 848         struct buffer_head *bh;
 849         ext4_fsblk_t newblock;
 850         int err = 0;
 851
 852         newblock = ext4_ext_new_block(handle, inode, path, newext, &err);
 853         if (newblock == 0)
 854                 return err;
 855
 856         bh = sb_getblk(inode->i_sb, newblock);
 857         if (!bh) {
 858                 err = -EIO;
 859                 ext4_std_error(inode->i_sb, err);
 860                 return err;
 861         }
 862         lock_buffer(bh);
 863
 864         if ((err = ext4_journal_get_create_access(handle, bh))) {
 865                 unlock_buffer(bh);
 866                 goto out;
 867         }
 868
 869         /* move top-level index/leaf into new block */
 870         memmove(bh->b_data, curp->p_hdr, sizeof(EXT4_I(inode)->i_data));
 871
 872         /* set size of new block */
 873         neh = ext_block_hdr(bh);
 874         /* old root could have indexes or leaves
 875          * so calculate e_max right way */
 876         if (ext_depth(inode))
 877           neh->eh_max = cpu_to_le16(ext4_ext_space_block_idx(inode));
 878         else
 879           neh->eh_max = cpu_to_le16(ext4_ext_space_block(inode));
 880         neh->eh_magic = EXT4_EXT_MAGIC;
 881         set_buffer_uptodate(bh);
 882         unlock_buffer(bh);
 883
 884         if ((err = ext4_journal_dirty_metadata(handle, bh)))
 885                 goto out;
 886
 887         /* create index in new top-level index: num,max,pointer */
 888         if ((err = ext4_ext_get_access(handle, inode, curp)))
 889                 goto out;
 890
 891         curp->p_hdr->eh_magic = EXT4_EXT_MAGIC;
 892         curp->p_hdr->eh_max = cpu_to_le16(ext4_ext_space_root_idx(inode));
 893         curp->p_hdr->eh_entries = cpu_to_le16(1);
 894         curp->p_idx = EXT_FIRST_INDEX(curp->p_hdr);
 895         /* FIXME: it works, but actually path[0] can be index */
 896         curp->p_idx->ei_block = EXT_FIRST_EXTENT(path[0].p_hdr)->ee_block;
 897         ext4_idx_store_pblock(curp->p_idx, newblock);
 898
 899         neh = ext_inode_hdr(inode);
 900         fidx = EXT_FIRST_INDEX(neh);
 901         ext_debug("new root: num %d(%d), lblock %d, ptr "E3FSBLK"\n",
 902                   le16_to_cpu(neh->eh_entries), le16_to_cpu(neh->eh_max),
 903                   le32_to_cpu(fidx->ei_block), idx_pblock(fidx));
 904
 905         neh->eh_depth = cpu_to_le16(path->p_depth + 1);
 906         err = ext4_ext_dirty(handle, inode, curp);
 907 out:
 908         brelse(bh);
 909
 910         return err;
 911 }
 912
 913 /*
 914  * ext4_ext_create_new_leaf:
 915  * finds empty index and adds new leaf.
 916  * if no free index is found, then it requests in-depth growing.
 917  */
 918 static int ext4_ext_create_new_leaf(handle_t *handle, struct inode *inode,
 919                                         struct ext4_ext_path *path,
 920                                         struct ext4_extent *newext)
 921 {
 922         struct ext4_ext_path *curp;
 923         int depth, i, err = 0;
 924
 925 repeat:
 926         i = depth = ext_depth(inode);
 927
 928         /* walk up to the tree and look for free index entry */
 929         curp = path + depth;
 930         while (i > 0 && !EXT_HAS_FREE_INDEX(curp)) {
 931                 i--;
 932                 curp--;
 933         }
 934
 935         /* we use already allocated block for index block,
 936          * so subsequent data blocks should be contiguous */
 937         if (EXT_HAS_FREE_INDEX(curp)) {
 938                 /* if we found index with free entry, then use that
 939                  * entry: create all needed subtree and add new leaf */
 940                 err = ext4_ext_split(handle, inode, path, newext, i);
 941
 942                 /* refill path */
 943                 ext4_ext_drop_refs(path);
 944                 path = ext4_ext_find_extent(inode,
 945                                             le32_to_cpu(newext->ee_block),
 946                                             path);
 947                 if (IS_ERR(path))
 948                         err = PTR_ERR(path);
 949         } else {
 950                 /* tree is full, time to grow in depth */
 951                 err = ext4_ext_grow_indepth(handle, inode, path, newext);
 952                 if (err)
 953                         goto out;
 954
 955                 /* refill path */
 956                 ext4_ext_drop_refs(path);
 957                 path = ext4_ext_find_extent(inode,
 958                                             le32_to_cpu(newext->ee_block),
 959                                             path);
 960                 if (IS_ERR(path)) {
 961                         err = PTR_ERR(path);
 962                         goto out;
 963                 }
 964
 965                 /*
 966                  * only first (depth 0 -> 1) produces free space;
 967                  * in all other cases we have to split the grown tree
 968                  */
 969                 depth = ext_depth(inode);
 970                 if (path[depth].p_hdr->eh_entries == path[depth].p_hdr->eh_max) {
 971                         /* now we need to split */
 972                         goto repeat;
 973                 }
 974         }
 975
 976 out:
 977         return err;
 978 }
 979
 980 /*
 981  * ext4_ext_next_allocated_block:
 982  * returns allocated block in subsequent extent or EXT_MAX_BLOCK.
 983  * NOTE: it considers block number from index entry as
 984  * allocated block. Thus, index entries have to be consistent
 985  * with leaves.
 986  */
 987 static unsigned long
 988 ext4_ext_next_allocated_block(struct ext4_ext_path *path)
 989 {
 990         int depth;
 991
 992         BUG_ON(path == NULL);
 993         depth = path->p_depth;
 994
 995         if (depth == 0 && path->p_ext == NULL)
 996                 return EXT_MAX_BLOCK;
 997
 998         while (depth >= 0) {
 999                 if (depth == path->p_depth) {
1000                         /* leaf */
1001                         if (path[depth].p_ext !=
1002                                         EXT_LAST_EXTENT(path[depth].p_hdr))
1003                           return le32_to_cpu(path[depth].p_ext[1].ee_block);
1004                 } else {
1005                         /* index */
1006                         if (path[depth].p_idx !=
1007                                         EXT_LAST_INDEX(path[depth].p_hdr))
1008                           return le32_to_cpu(path[depth].p_idx[1].ei_block);
1009                 }
1010                 depth--;
1011         }
1012
1013         return EXT_MAX_BLOCK;
1014 }
1015
1016 /*
1017  * ext4_ext_next_leaf_block:
1018  * returns first allocated block from next leaf or EXT_MAX_BLOCK
1019  */
1020 static unsigned ext4_ext_next_leaf_block(struct inode *inode,
1021                                                struct ext4_ext_path *path)
1022 {
1023         int depth;
1024
1025         BUG_ON(path == NULL);
1026         depth = path->p_depth;
1027
1028         /* zero-tree has no leaf blocks at all */
1029         if (depth == 0)
1030                 return EXT_MAX_BLOCK;
1031
1032         /* go to index block */
1033         depth--;
1034
1035         while (depth >= 0) {
1036                 if (path[depth].p_idx !=
1037                                 EXT_LAST_INDEX(path[depth].p_hdr))
1038                   return le32_to_cpu(path[depth].p_idx[1].ei_block);
1039                 depth--;
1040         }
1041
1042         return EXT_MAX_BLOCK;
1043 }
1044
1045 /*
1046  * ext4_ext_correct_indexes:
1047  * if leaf gets modified and modified extent is first in the leaf,
1048  * then we have to correct all indexes above.
1049  * TODO: do we need to correct tree in all cases?
1050  */
1051 int ext4_ext_correct_indexes(handle_t *handle, struct inode *inode,
1052                                 struct ext4_ext_path *path)
1053 {
1054         struct ext4_extent_header *eh;
1055         int depth = ext_depth(inode);
1056         struct ext4_extent *ex;
1057         __le32 border;
1058         int k, err = 0;
1059
1060         eh = path[depth].p_hdr;
1061         ex = path[depth].p_ext;
1062         BUG_ON(ex == NULL);
1063         BUG_ON(eh == NULL);
1064
1065         if (depth == 0) {
1066                 /* there is no tree at all */
1067                 return 0;
1068         }
1069
1070         if (ex != EXT_FIRST_EXTENT(eh)) {
1071                 /* we correct tree if first leaf got modified only */
1072                 return 0;
1073         }
1074
1075         /*
1076          * TODO: we need correction if border is smaller than current one
1077          */
1078         k = depth - 1;
1079         border = path[depth].p_ext->ee_block;
1080         if ((err = ext4_ext_get_access(handle, inode, path + k)))
1081                 return err;
1082         path[k].p_idx->ei_block = border;
1083         if ((err = ext4_ext_dirty(handle, inode, path + k)))
1084                 return err;
1085
1086         while (k--) {
1087                 /* change all left-side indexes */
1088                 if (path[k+1].p_idx != EXT_FIRST_INDEX(path[k+1].p_hdr))
1089                         break;
1090                 if ((err = ext4_ext_get_access(handle, inode, path + k)))
1091                         break;
1092                 path[k].p_idx->ei_block = border;
1093                 if ((err = ext4_ext_dirty(handle, inode, path + k)))
1094                         break;
1095         }
1096
1097         return err;
1098 }
1099
1100 static int inline
1101 ext4_can_extents_be_merged(struct inode *inode, struct ext4_extent *ex1,
1102                                 struct ext4_extent *ex2)
1103 {
1104         if (le32_to_cpu(ex1->ee_block) + le16_to_cpu(ex1->ee_len)
1105             != le32_to_cpu(ex2->ee_block))
1106                 return 0;
1107
1108         /*
1109          * To allow future support for preallocated extents to be added
1110          * as an RO_COMPAT feature, refuse to merge to extents if
1111          * this can result in the top bit of ee_len being set.
1112          */
1113         if (le16_to_cpu(ex1->ee_len) + le16_to_cpu(ex2->ee_len) > EXT_MAX_LEN)
1114                 return 0;
1115 #ifdef AGRESSIVE_TEST
1116         if (le16_to_cpu(ex1->ee_len) >= 4)
1117                 return 0;
1118 #endif
1119
1120         if (ext_pblock(ex1) + le16_to_cpu(ex1->ee_len) == ext_pblock(ex2))
1121                 return 1;
1122         return 0;
1123 }
1124
1125 /*
1126  * ext4_ext_insert_extent:
1127  * tries to merge requsted extent into the existing extent or
1128  * inserts requested extent as new one into the tree,
1129  * creating new leaf in the no-space case.
1130  */
1131 int ext4_ext_insert_extent(handle_t *handle, struct inode *inode,
1132                                 struct ext4_ext_path *path,
1133                                 struct ext4_extent *newext)
1134 {
1135         struct ext4_extent_header * eh;
1136         struct ext4_extent *ex, *fex;
1137         struct ext4_extent *nearex; /* nearest extent */
1138         struct ext4_ext_path *npath = NULL;
1139         int depth, len, err, next;
1140
1141         BUG_ON(newext->ee_len == 0);
1142         depth = ext_depth(inode);
1143         ex = path[depth].p_ext;
1144         BUG_ON(path[depth].p_hdr == NULL);
1145
1146         /* try to insert block into found extent and return */
1147         if (ex && ext4_can_extents_be_merged(inode, ex, newext)) {
1148                 ext_debug("append %d block to %d:%d (from "E3FSBLK")\n",
1149                                 le16_to_cpu(newext->ee_len),
1150                                 le32_to_cpu(ex->ee_block),
1151                                 le16_to_cpu(ex->ee_len), ext_pblock(ex));
1152                 if ((err = ext4_ext_get_access(handle, inode, path + depth)))
1153                         return err;
1154                 ex->ee_len = cpu_to_le16(le16_to_cpu(ex->ee_len)
1155                                          + le16_to_cpu(newext->ee_len));
1156                 eh = path[depth].p_hdr;
1157                 nearex = ex;
1158                 goto merge;
1159         }
1160
1161 repeat:
1162         depth = ext_depth(inode);
1163         eh = path[depth].p_hdr;
1164         if (le16_to_cpu(eh->eh_entries) < le16_to_cpu(eh->eh_max))
1165                 goto has_space;
1166
1167         /* probably next leaf has space for us? */
1168         fex = EXT_LAST_EXTENT(eh);
1169         next = ext4_ext_next_leaf_block(inode, path);
1170         if (le32_to_cpu(newext->ee_block) > le32_to_cpu(fex->ee_block)
1171             && next != EXT_MAX_BLOCK) {
1172                 ext_debug("next leaf block - %d\n", next);
1173                 BUG_ON(npath != NULL);
1174                 npath = ext4_ext_find_extent(inode, next, NULL);
1175                 if (IS_ERR(npath))
1176                         return PTR_ERR(npath);
1177                 BUG_ON(npath->p_depth != path->p_depth);
1178                 eh = npath[depth].p_hdr;
1179                 if (le16_to_cpu(eh->eh_entries) < le16_to_cpu(eh->eh_max)) {
1180                         ext_debug("next leaf isnt full(%d)\n",
1181                                   le16_to_cpu(eh->eh_entries));
1182                         path = npath;
1183                         goto repeat;
1184                 }
1185                 ext_debug("next leaf has no free space(%d,%d)\n",
1186                           le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max));
1187         }
1188
1189         /*
1190          * There is no free space in the found leaf.
1191          * We're gonna add a new leaf in the tree.
1192          */
1193         err = ext4_ext_create_new_leaf(handle, inode, path, newext);
1194         if (err)
1195                 goto cleanup;
1196         depth = ext_depth(inode);
1197         eh = path[depth].p_hdr;
1198
1199 has_space:
1200         nearex = path[depth].p_ext;
1201
1202         if ((err = ext4_ext_get_access(handle, inode, path + depth)))
1203                 goto cleanup;
1204
1205         if (!nearex) {
1206                 /* there is no extent in this leaf, create first one */
1207                 ext_debug("first extent in the leaf: %d:"E3FSBLK":%d\n",
1208                                 le32_to_cpu(newext->ee_block),
1209                                 ext_pblock(newext),
1210                                 le16_to_cpu(newext->ee_len));
1211                 path[depth].p_ext = EXT_FIRST_EXTENT(eh);
1212         } else if (le32_to_cpu(newext->ee_block)
1213                            > le32_to_cpu(nearex->ee_block)) {
1214 /*              BUG_ON(newext->ee_block == nearex->ee_block); */
1215                 if (nearex != EXT_LAST_EXTENT(eh)) {
1216                         len = EXT_MAX_EXTENT(eh) - nearex;
1217                         len = (len - 1) * sizeof(struct ext4_extent);
1218                         len = len < 0 ? 0 : len;
1219                         ext_debug("insert %d:"E3FSBLK":%d after: nearest 0x%p, "
1220                                         "move %d from 0x%p to 0x%p\n",
1221                                         le32_to_cpu(newext->ee_block),
1222                                         ext_pblock(newext),
1223                                         le16_to_cpu(newext->ee_len),
1224                                         nearex, len, nearex + 1, nearex + 2);
1225                         memmove(nearex + 2, nearex + 1, len);
1226                 }
1227                 path[depth].p_ext = nearex + 1;
1228         } else {
1229                 BUG_ON(newext->ee_block == nearex->ee_block);
1230                 len = (EXT_MAX_EXTENT(eh) - nearex) * sizeof(struct ext4_extent);
1231                 len = len < 0 ? 0 : len;
1232                 ext_debug("insert %d:"E3FSBLK":%d before: nearest 0x%p, "
1233                                 "move %d from 0x%p to 0x%p\n",
1234                                 le32_to_cpu(newext->ee_block),
1235                                 ext_pblock(newext),
1236                                 le16_to_cpu(newext->ee_len),
1237                                 nearex, len, nearex + 1, nearex + 2);
1238                 memmove(nearex + 1, nearex, len);
1239                 path[depth].p_ext = nearex;
1240         }
1241
1242         eh->eh_entries = cpu_to_le16(le16_to_cpu(eh->eh_entries)+1);
1243         nearex = path[depth].p_ext;
1244         nearex->ee_block = newext->ee_block;
1245         nearex->ee_start = newext->ee_start;
1246         nearex->ee_start_hi = newext->ee_start_hi;
1247         nearex->ee_len = newext->ee_len;
1248
1249 merge:
1250         /* try to merge extents to the right */
1251         while (nearex < EXT_LAST_EXTENT(eh)) {
1252                 if (!ext4_can_extents_be_merged(inode, nearex, nearex + 1))
1253                         break;
1254                 /* merge with next extent! */
1255                 nearex->ee_len = cpu_to_le16(le16_to_cpu(nearex->ee_len)
1256                                              + le16_to_cpu(nearex[1].ee_len));
1257                 if (nearex + 1 < EXT_LAST_EXTENT(eh)) {
1258                         len = (EXT_LAST_EXTENT(eh) - nearex - 1)
1259                                         * sizeof(struct ext4_extent);
1260                         memmove(nearex + 1, nearex + 2, len);
1261                 }
1262                 eh->eh_entries = cpu_to_le16(le16_to_cpu(eh->eh_entries)-1);
1263                 BUG_ON(eh->eh_entries == 0);
1264         }
1265
1266         /* try to merge extents to the left */
1267
1268         /* time to correct all indexes above */
1269         err = ext4_ext_correct_indexes(handle, inode, path);
1270         if (err)
1271                 goto cleanup;
1272
1273         err = ext4_ext_dirty(handle, inode, path + depth);
1274
1275 cleanup:
1276         if (npath) {
1277                 ext4_ext_drop_refs(npath);
1278                 kfree(npath);
1279         }
1280         ext4_ext_tree_changed(inode);
1281         ext4_ext_invalidate_cache(inode);
1282         return err;
1283 }
1284
1285 int ext4_ext_walk_space(struct inode *inode, unsigned long block,
1286                         unsigned long num, ext_prepare_callback func,
1287                         void *cbdata)
1288 {
1289         struct ext4_ext_path *path = NULL;
1290         struct ext4_ext_cache cbex;
1291         struct ext4_extent *ex;
1292         unsigned long next, start = 0, end = 0;
1293         unsigned long last = block + num;
1294         int depth, exists, err = 0;
1295
1296         BUG_ON(func == NULL);
1297         BUG_ON(inode == NULL);
1298
1299         while (block < last && block != EXT_MAX_BLOCK) {
1300                 num = last - block;
1301                 /* find extent for this block */
1302                 path = ext4_ext_find_extent(inode, block, path);
1303                 if (IS_ERR(path)) {
1304                         err = PTR_ERR(path);
1305                         path = NULL;
1306                         break;
1307                 }
1308
1309                 depth = ext_depth(inode);
1310                 BUG_ON(path[depth].p_hdr == NULL);
1311                 ex = path[depth].p_ext;
1312                 next = ext4_ext_next_allocated_block(path);
1313
1314                 exists = 0;
1315                 if (!ex) {
1316                         /* there is no extent yet, so try to allocate
1317                          * all requested space */
1318                         start = block;
1319                         end = block + num;
1320                 } else if (le32_to_cpu(ex->ee_block) > block) {
1321                         /* need to allocate space before found extent */
1322                         start = block;
1323                         end = le32_to_cpu(ex->ee_block);
1324                         if (block + num < end)
1325                                 end = block + num;
1326                 } else if (block >=
1327                              le32_to_cpu(ex->ee_block) + le16_to_cpu(ex->ee_len)) {
1328                         /* need to allocate space after found extent */
1329                         start = block;
1330                         end = block + num;
1331                         if (end >= next)
1332                                 end = next;
1333                 } else if (block >= le32_to_cpu(ex->ee_block)) {
1334                         /*
1335                          * some part of requested space is covered
1336                          * by found extent
1337                          */
1338                         start = block;
1339                         end = le32_to_cpu(ex->ee_block) + le16_to_cpu(ex->ee_len);
1340                         if (block + num < end)
1341                                 end = block + num;
1342                         exists = 1;
1343                 } else {
1344                         BUG();
1345                 }
1346                 BUG_ON(end <= start);
1347
1348                 if (!exists) {
1349                         cbex.ec_block = start;
1350                         cbex.ec_len = end - start;
1351                         cbex.ec_start = 0;
1352                         cbex.ec_type = EXT4_EXT_CACHE_GAP;
1353                 } else {
1354                         cbex.ec_block = le32_to_cpu(ex->ee_block);
1355                         cbex.ec_len = le16_to_cpu(ex->ee_len);
1356                         cbex.ec_start = ext_pblock(ex);
1357                         cbex.ec_type = EXT4_EXT_CACHE_EXTENT;
1358                 }
1359
1360                 BUG_ON(cbex.ec_len == 0);
1361                 err = func(inode, path, &cbex, cbdata);
1362                 ext4_ext_drop_refs(path);
1363
1364                 if (err < 0)
1365                         break;
1366                 if (err == EXT_REPEAT)
1367                         continue;
1368                 else if (err == EXT_BREAK) {
1369                         err = 0;
1370                         break;
1371                 }
1372
1373                 if (ext_depth(inode) != depth) {
1374                         /* depth was changed. we have to realloc path */
1375                         kfree(path);
1376                         path = NULL;
1377                 }
1378
1379                 block = cbex.ec_block + cbex.ec_len;
1380         }
1381
1382         if (path) {
1383                 ext4_ext_drop_refs(path);
1384                 kfree(path);
1385         }
1386
1387         return err;
1388 }
1389
1390 static inline void
1391 ext4_ext_put_in_cache(struct inode *inode, __u32 block,
1392                         __u32 len, __u32 start, int type)
1393 {
1394         struct ext4_ext_cache *cex;
1395         BUG_ON(len == 0);
1396         cex = &EXT4_I(inode)->i_cached_extent;
1397         cex->ec_type = type;
1398         cex->ec_block = block;
1399         cex->ec_len = len;
1400         cex->ec_start = start;
1401 }
1402
1403 /*
1404  * ext4_ext_put_gap_in_cache:
1405  * calculate boundaries of the gap that the requested block fits into
1406  * and cache this gap
1407  */
1408 static inline void
1409 ext4_ext_put_gap_in_cache(struct inode *inode, struct ext4_ext_path *path,
1410                                 unsigned long block)
1411 {
1412         int depth = ext_depth(inode);
1413         unsigned long lblock, len;
1414         struct ext4_extent *ex;
1415
1416         ex = path[depth].p_ext;
1417         if (ex == NULL) {
1418                 /* there is no extent yet, so gap is [0;-] */
1419                 lblock = 0;
1420                 len = EXT_MAX_BLOCK;
1421                 ext_debug("cache gap(whole file):");
1422         } else if (block < le32_to_cpu(ex->ee_block)) {
1423                 lblock = block;
1424                 len = le32_to_cpu(ex->ee_block) - block;
1425                 ext_debug("cache gap(before): %lu [%lu:%lu]",
1426                                 (unsigned long) block,
1427                                 (unsigned long) le32_to_cpu(ex->ee_block),
1428                                 (unsigned long) le16_to_cpu(ex->ee_len));
1429         } else if (block >= le32_to_cpu(ex->ee_block)
1430                             + le16_to_cpu(ex->ee_len)) {
1431                 lblock = le32_to_cpu(ex->ee_block)
1432                          + le16_to_cpu(ex->ee_len);
1433                 len = ext4_ext_next_allocated_block(path);
1434                 ext_debug("cache gap(after): [%lu:%lu] %lu",
1435                                 (unsigned long) le32_to_cpu(ex->ee_block),
1436                                 (unsigned long) le16_to_cpu(ex->ee_len),
1437                                 (unsigned long) block);
1438                 BUG_ON(len == lblock);
1439                 len = len - lblock;
1440         } else {
1441                 lblock = len = 0;
1442                 BUG();
1443         }
1444
1445         ext_debug(" -> %lu:%lu\n", (unsigned long) lblock, len);
1446         ext4_ext_put_in_cache(inode, lblock, len, 0, EXT4_EXT_CACHE_GAP);
1447 }
1448
1449 static inline int
1450 ext4_ext_in_cache(struct inode *inode, unsigned long block,
1451                         struct ext4_extent *ex)
1452 {
1453         struct ext4_ext_cache *cex;
1454
1455         cex = &EXT4_I(inode)->i_cached_extent;
1456
1457         /* has cache valid data? */
1458         if (cex->ec_type == EXT4_EXT_CACHE_NO)
1459                 return EXT4_EXT_CACHE_NO;
1460
1461         BUG_ON(cex->ec_type != EXT4_EXT_CACHE_GAP &&
1462                         cex->ec_type != EXT4_EXT_CACHE_EXTENT);
1463         if (block >= cex->ec_block && block < cex->ec_block + cex->ec_len) {
1464                 ex->ee_block = cpu_to_le32(cex->ec_block);
1465                 ext4_ext_store_pblock(ex, cex->ec_start);
1466                 ex->ee_len = cpu_to_le16(cex->ec_len);
1467                 ext_debug("%lu cached by %lu:%lu:"E3FSBLK"\n",
1468                                 (unsigned long) block,
1469                                 (unsigned long) cex->ec_block,
1470                                 (unsigned long) cex->ec_len,
1471                                 cex->ec_start);
1472                 return cex->ec_type;
1473         }
1474
1475         /* not in cache */
1476         return EXT4_EXT_CACHE_NO;
1477 }
1478
1479 /*
1480  * ext4_ext_rm_idx:
1481  * removes index from the index block.
1482  * It's used in truncate case only, thus all requests are for
1483  * last index in the block only.
1484  */
1485 int ext4_ext_rm_idx(handle_t *handle, struct inode *inode,
1486                         struct ext4_ext_path *path)
1487 {
1488         struct buffer_head *bh;
1489         int err;
1490         ext4_fsblk_t leaf;
1491
1492         /* free index block */
1493         path--;
1494         leaf = idx_pblock(path->p_idx);
1495         BUG_ON(path->p_hdr->eh_entries == 0);
1496         if ((err = ext4_ext_get_access(handle, inode, path)))
1497                 return err;
1498         path->p_hdr->eh_entries = cpu_to_le16(le16_to_cpu(path->p_hdr->eh_entries)-1);
1499         if ((err = ext4_ext_dirty(handle, inode, path)))
1500                 return err;
1501         ext_debug("index is empty, remove it, free block "E3FSBLK"\n", leaf);
1502         bh = sb_find_get_block(inode->i_sb, leaf);
1503         ext4_forget(handle, 1, inode, bh, leaf);
1504         ext4_free_blocks(handle, inode, leaf, 1);
1505         return err;
1506 }
1507
1508 /*
1509  * ext4_ext_calc_credits_for_insert:
1510  * This routine returns max. credits that the extent tree can consume.
1511  * It should be OK for low-performance paths like ->writepage()
1512  * To allow many writing processes to fit into a single transaction,
1513  * the caller should calculate credits under truncate_mutex and
1514  * pass the actual path.
1515  */
1516 int inline ext4_ext_calc_credits_for_insert(struct inode *inode,
1517                                                 struct ext4_ext_path *path)
1518 {
1519         int depth, needed;
1520
1521         if (path) {
1522                 /* probably there is space in leaf? */
1523                 depth = ext_depth(inode);
1524                 if (le16_to_cpu(path[depth].p_hdr->eh_entries)
1525                                 < le16_to_cpu(path[depth].p_hdr->eh_max))
1526                         return 1;
1527         }
1528
1529         /*
1530          * given 32-bit logical block (4294967296 blocks), max. tree
1531          * can be 4 levels in depth -- 4 * 340^4 == 53453440000.
1532          * Let's also add one more level for imbalance.
1533          */
1534         depth = 5;
1535
1536         /* allocation of new data block(s) */
1537         needed = 2;
1538
1539         /*
1540          * tree can be full, so it would need to grow in depth:
1541          * allocation + old root + new root
1542          */
1543         needed += 2 + 1 + 1;
1544
1545         /*
1546          * Index split can happen, we would need:
1547          *    allocate intermediate indexes (bitmap + group)
1548          *  + change two blocks at each level, but root (already included)
1549          */
1550         needed = (depth * 2) + (depth * 2);
1551
1552         /* any allocation modifies superblock */
1553         needed += 1;
1554
1555         return needed;
1556 }
1557
1558 static int ext4_remove_blocks(handle_t *handle, struct inode *inode,
1559                                 struct ext4_extent *ex,
1560                                 unsigned long from, unsigned long to)
1561 {
1562         struct buffer_head *bh;
1563         int i;
1564
1565 #ifdef EXTENTS_STATS
1566         {
1567                 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
1568                 unsigned short ee_len =  le16_to_cpu(ex->ee_len);
1569                 spin_lock(&sbi->s_ext_stats_lock);
1570                 sbi->s_ext_blocks += ee_len;
1571                 sbi->s_ext_extents++;
1572                 if (ee_len < sbi->s_ext_min)
1573                         sbi->s_ext_min = ee_len;
1574                 if (ee_len > sbi->s_ext_max)
1575                         sbi->s_ext_max = ee_len;
1576                 if (ext_depth(inode) > sbi->s_depth_max)
1577                         sbi->s_depth_max = ext_depth(inode);
1578                 spin_unlock(&sbi->s_ext_stats_lock);
1579         }
1580 #endif
1581         if (from >= le32_to_cpu(ex->ee_block)
1582             && to == le32_to_cpu(ex->ee_block) + le16_to_cpu(ex->ee_len) - 1) {
1583                 /* tail removal */
1584                 unsigned long num;
1585                 ext4_fsblk_t start;
1586                 num = le32_to_cpu(ex->ee_block) + le16_to_cpu(ex->ee_len) - from;
1587                 start = ext_pblock(ex) + le16_to_cpu(ex->ee_len) - num;
1588                 ext_debug("free last %lu blocks starting "E3FSBLK"\n", num, start);
1589                 for (i = 0; i < num; i++) {
1590                         bh = sb_find_get_block(inode->i_sb, start + i);
1591                         ext4_forget(handle, 0, inode, bh, start + i);
1592                 }
1593                 ext4_free_blocks(handle, inode, start, num);
1594         } else if (from == le32_to_cpu(ex->ee_block)
1595                    && to <= le32_to_cpu(ex->ee_block) + le16_to_cpu(ex->ee_len) - 1) {
1596                 printk("strange request: removal %lu-%lu from %u:%u\n",
1597                        from, to, le32_to_cpu(ex->ee_block), le16_to_cpu(ex->ee_len));
1598         } else {
1599                 printk("strange request: removal(2) %lu-%lu from %u:%u\n",
1600                        from, to, le32_to_cpu(ex->ee_block), le16_to_cpu(ex->ee_len));
1601         }
1602         return 0;
1603 }
1604
1605 static int
1606 ext4_ext_rm_leaf(handle_t *handle, struct inode *inode,
1607                 struct ext4_ext_path *path, unsigned long start)
1608 {
1609         int err = 0, correct_index = 0;
1610         int depth = ext_depth(inode), credits;
1611         struct ext4_extent_header *eh;
1612         unsigned a, b, block, num;
1613         unsigned long ex_ee_block;
1614         unsigned short ex_ee_len;
1615         struct ext4_extent *ex;
1616
1617         ext_debug("truncate since %lu in leaf\n", start);
1618         if (!path[depth].p_hdr)
1619                 path[depth].p_hdr = ext_block_hdr(path[depth].p_bh);
1620         eh = path[depth].p_hdr;
1621         BUG_ON(eh == NULL);
1622         BUG_ON(le16_to_cpu(eh->eh_entries) > le16_to_cpu(eh->eh_max));
1623         BUG_ON(eh->eh_magic != EXT4_EXT_MAGIC);
1624
1625         /* find where to start removing */
1626         ex = EXT_LAST_EXTENT(eh);
1627
1628         ex_ee_block = le32_to_cpu(ex->ee_block);
1629         ex_ee_len = le16_to_cpu(ex->ee_len);
1630
1631         while (ex >= EXT_FIRST_EXTENT(eh) &&
1632                         ex_ee_block + ex_ee_len > start) {
1633                 ext_debug("remove ext %lu:%u\n", ex_ee_block, ex_ee_len);
1634                 path[depth].p_ext = ex;
1635
1636                 a = ex_ee_block > start ? ex_ee_block : start;
1637                 b = ex_ee_block + ex_ee_len - 1 < EXT_MAX_BLOCK ?
1638                         ex_ee_block + ex_ee_len - 1 : EXT_MAX_BLOCK;
1639
1640                 ext_debug("  border %u:%u\n", a, b);
1641
1642                 if (a != ex_ee_block && b != ex_ee_block + ex_ee_len - 1) {
1643                         block = 0;
1644                         num = 0;
1645                         BUG();
1646                 } else if (a != ex_ee_block) {
1647                         /* remove tail of the extent */
1648                         block = ex_ee_block;
1649                         num = a - block;
1650                 } else if (b != ex_ee_block + ex_ee_len - 1) {
1651                         /* remove head of the extent */
1652                         block = a;
1653                         num = b - a;
1654                         /* there is no "make a hole" API yet */
1655                         BUG();
1656                 } else {
1657                         /* remove whole extent: excellent! */
1658                         block = ex_ee_block;
1659                         num = 0;
1660                         BUG_ON(a != ex_ee_block);
1661                         BUG_ON(b != ex_ee_block + ex_ee_len - 1);
1662                 }
1663
1664                 /* at present, extent can't cross block group: */
1665                 /* leaf + bitmap + group desc + sb + inode */
1666                 credits = 5;
1667                 if (ex == EXT_FIRST_EXTENT(eh)) {
1668                         correct_index = 1;
1669                         credits += (ext_depth(inode)) + 1;
1670                 }
1671 #ifdef CONFIG_QUOTA
1672                 credits += 2 * EXT4_QUOTA_TRANS_BLOCKS(inode->i_sb);
1673 #endif
1674
1675                 handle = ext4_ext_journal_restart(handle, credits);
1676                 if (IS_ERR(handle)) {
1677                         err = PTR_ERR(handle);
1678                         goto out;
1679                 }
1680
1681                 err = ext4_ext_get_access(handle, inode, path + depth);
1682                 if (err)
1683                         goto out;
1684
1685                 err = ext4_remove_blocks(handle, inode, ex, a, b);
1686                 if (err)
1687                         goto out;
1688
1689                 if (num == 0) {
1690                         /* this extent is removed; mark slot entirely unused */
1691                         ext4_ext_store_pblock(ex, 0);
1692                         eh->eh_entries = cpu_to_le16(le16_to_cpu(eh->eh_entries)-1);
1693                 }
1694
1695                 ex->ee_block = cpu_to_le32(block);
1696                 ex->ee_len = cpu_to_le16(num);
1697
1698                 err = ext4_ext_dirty(handle, inode, path + depth);
1699                 if (err)
1700                         goto out;
1701
1702                 ext_debug("new extent: %u:%u:"E3FSBLK"\n", block, num,
1703                                 ext_pblock(ex));
1704                 ex--;
1705                 ex_ee_block = le32_to_cpu(ex->ee_block);
1706                 ex_ee_len = le16_to_cpu(ex->ee_len);
1707         }
1708
1709         if (correct_index && eh->eh_entries)
1710                 err = ext4_ext_correct_indexes(handle, inode, path);
1711
1712         /* if this leaf is free, then we should
1713          * remove it from index block above */
1714         if (err == 0 && eh->eh_entries == 0 && path[depth].p_bh != NULL)
1715                 err = ext4_ext_rm_idx(handle, inode, path + depth);
1716
1717 out:
1718         return err;
1719 }
1720
1721 /*
1722  * ext4_ext_more_to_rm:
1723  * returns 1 if current index has to be freed (even partial)
1724  */
1725 static int inline
1726 ext4_ext_more_to_rm(struct ext4_ext_path *path)
1727 {
1728         BUG_ON(path->p_idx == NULL);
1729
1730         if (path->p_idx < EXT_FIRST_INDEX(path->p_hdr))
1731                 return 0;
1732
1733         /*
1734          * if truncate on deeper level happened, it wasn't partial,
1735          * so we have to consider current index for truncation
1736          */
1737         if (le16_to_cpu(path->p_hdr->eh_entries) == path->p_block)
1738                 return 0;
1739         return 1;
1740 }
1741
1742 int ext4_ext_remove_space(struct inode *inode, unsigned long start)
1743 {
1744         struct super_block *sb = inode->i_sb;
1745         int depth = ext_depth(inode);
1746         struct ext4_ext_path *path;
1747         handle_t *handle;
1748         int i = 0, err = 0;
1749
1750         ext_debug("truncate since %lu\n", start);
1751
1752         /* probably first extent we're gonna free will be last in block */
1753         handle = ext4_journal_start(inode, depth + 1);
1754         if (IS_ERR(handle))
1755                 return PTR_ERR(handle);
1756
1757         ext4_ext_invalidate_cache(inode);
1758
1759         /*
1760          * We start scanning from right side, freeing all the blocks
1761          * after i_size and walking into the tree depth-wise.
1762          */
1763         path = kmalloc(sizeof(struct ext4_ext_path) * (depth + 1), GFP_KERNEL);
1764         if (path == NULL) {
1765                 ext4_journal_stop(handle);
1766                 return -ENOMEM;
1767         }
1768         memset(path, 0, sizeof(struct ext4_ext_path) * (depth + 1));
1769         path[0].p_hdr = ext_inode_hdr(inode);
1770         if (ext4_ext_check_header(__FUNCTION__, inode, path[0].p_hdr)) {
1771                 err = -EIO;
1772                 goto out;
1773         }
1774         path[0].p_depth = depth;
1775
1776         while (i >= 0 && err == 0) {
1777                 if (i == depth) {
1778                         /* this is leaf block */
1779                         err = ext4_ext_rm_leaf(handle, inode, path, start);
1780                         /* root level has p_bh == NULL, brelse() eats this */
1781                         brelse(path[i].p_bh);
1782                         path[i].p_bh = NULL;
1783                         i--;
1784                         continue;
1785                 }
1786
1787                 /* this is index block */
1788                 if (!path[i].p_hdr) {
1789                         ext_debug("initialize header\n");
1790                         path[i].p_hdr = ext_block_hdr(path[i].p_bh);
1791                         if (ext4_ext_check_header(__FUNCTION__, inode,
1792                                                         path[i].p_hdr)) {
1793                                 err = -EIO;
1794                                 goto out;
1795                         }
1796                 }
1797
1798                 BUG_ON(le16_to_cpu(path[i].p_hdr->eh_entries)
1799                            > le16_to_cpu(path[i].p_hdr->eh_max));
1800                 BUG_ON(path[i].p_hdr->eh_magic != EXT4_EXT_MAGIC);
1801
1802                 if (!path[i].p_idx) {
1803                         /* this level hasn't been touched yet */
1804                         path[i].p_idx = EXT_LAST_INDEX(path[i].p_hdr);
1805                         path[i].p_block = le16_to_cpu(path[i].p_hdr->eh_entries)+1;
1806                         ext_debug("init index ptr: hdr 0x%p, num %d\n",
1807                                   path[i].p_hdr,
1808                                   le16_to_cpu(path[i].p_hdr->eh_entries));
1809                 } else {
1810                         /* we were already here, see at next index */
1811                         path[i].p_idx--;
1812                 }
1813
1814                 ext_debug("level %d - index, first 0x%p, cur 0x%p\n",
1815                                 i, EXT_FIRST_INDEX(path[i].p_hdr),
1816                                 path[i].p_idx);
1817                 if (ext4_ext_more_to_rm(path + i)) {
1818                         /* go to the next level */
1819                         ext_debug("move to level %d (block "E3FSBLK")\n",
1820                                   i + 1, idx_pblock(path[i].p_idx));
1821                         memset(path + i + 1, 0, sizeof(*path));
1822                         path[i+1].p_bh =
1823                                 sb_bread(sb, idx_pblock(path[i].p_idx));
1824                         if (!path[i+1].p_bh) {
1825                                 /* should we reset i_size? */
1826                                 err = -EIO;
1827                                 break;
1828                         }
1829
1830                         /* save actual number of indexes since this
1831                          * number is changed at the next iteration */
1832                         path[i].p_block = le16_to_cpu(path[i].p_hdr->eh_entries);
1833                         i++;
1834                 } else {
1835                         /* we finished processing this index, go up */
1836                         if (path[i].p_hdr->eh_entries == 0 && i > 0) {
1837                                 /* index is empty, remove it;
1838                                  * handle must be already prepared by the
1839                                  * truncatei_leaf() */
1840                                 err = ext4_ext_rm_idx(handle, inode, path + i);
1841                         }
1842                         /* root level has p_bh == NULL, brelse() eats this */
1843                         brelse(path[i].p_bh);
1844                         path[i].p_bh = NULL;
1845                         i--;
1846                         ext_debug("return to level %d\n", i);
1847                 }
1848         }
1849
1850         /* TODO: flexible tree reduction should be here */
1851         if (path->p_hdr->eh_entries == 0) {
1852                 /*
1853                  * truncate to zero freed all the tree,
1854                  * so we need to correct eh_depth
1855                  */
1856                 err = ext4_ext_get_access(handle, inode, path);
1857                 if (err == 0) {
1858                         ext_inode_hdr(inode)->eh_depth = 0;
1859                         ext_inode_hdr(inode)->eh_max =
1860                                 cpu_to_le16(ext4_ext_space_root(inode));
1861                         err = ext4_ext_dirty(handle, inode, path);
1862                 }
1863         }
1864 out:
1865         ext4_ext_tree_changed(inode);
1866         ext4_ext_drop_refs(path);
1867         kfree(path);
1868         ext4_journal_stop(handle);
1869
1870         return err;
1871 }
1872
1873 /*
1874  * called at mount time
1875  */
1876 void ext4_ext_init(struct super_block *sb)
1877 {
1878         /*
1879          * possible initialization would be here
1880          */
1881
1882         if (test_opt(sb, EXTENTS)) {
1883                 printk("EXT4-fs: file extents enabled");
1884 #ifdef AGRESSIVE_TEST
1885                 printk(", agressive tests");
1886 #endif
1887 #ifdef CHECK_BINSEARCH
1888                 printk(", check binsearch");
1889 #endif
1890 #ifdef EXTENTS_STATS
1891                 printk(", stats");
1892 #endif
1893                 printk("\n");
1894 #ifdef EXTENTS_STATS
1895                 spin_lock_init(&EXT4_SB(sb)->s_ext_stats_lock);
1896                 EXT4_SB(sb)->s_ext_min = 1 << 30;
1897                 EXT4_SB(sb)->s_ext_max = 0;
1898 #endif
1899         }
1900 }
1901
1902 /*
1903  * called at umount time
1904  */
1905 void ext4_ext_release(struct super_block *sb)
1906 {
1907         if (!test_opt(sb, EXTENTS))
1908                 return;
1909
1910 #ifdef EXTENTS_STATS
1911         if (EXT4_SB(sb)->s_ext_blocks && EXT4_SB(sb)->s_ext_extents) {
1912                 struct ext4_sb_info *sbi = EXT4_SB(sb);
1913                 printk(KERN_ERR "EXT4-fs: %lu blocks in %lu extents (%lu ave)\n",
1914                         sbi->s_ext_blocks, sbi->s_ext_extents,
1915                         sbi->s_ext_blocks / sbi->s_ext_extents);
1916                 printk(KERN_ERR "EXT4-fs: extents: %lu min, %lu max, max depth %lu\n",
1917                         sbi->s_ext_min, sbi->s_ext_max, sbi->s_depth_max);
1918         }
1919 #endif
1920 }
1921
1922 int ext4_ext_get_blocks(handle_t *handle, struct inode *inode,
1923                         ext4_fsblk_t iblock,
1924                         unsigned long max_blocks, struct buffer_head *bh_result,
1925                         int create, int extend_disksize)
1926 {
1927         struct ext4_ext_path *path = NULL;
1928         struct ext4_extent newex, *ex;
1929         ext4_fsblk_t goal, newblock;
1930         int err = 0, depth;
1931         unsigned long allocated = 0;
1932
1933         __clear_bit(BH_New, &bh_result->b_state);
1934         ext_debug("blocks %d/%lu requested for inode %u\n", (int) iblock,
1935                         max_blocks, (unsigned) inode->i_ino);
1936         mutex_lock(&EXT4_I(inode)->truncate_mutex);
1937
1938         /* check in cache */
1939         if ((goal = ext4_ext_in_cache(inode, iblock, &newex))) {
1940                 if (goal == EXT4_EXT_CACHE_GAP) {
1941                         if (!create) {
1942                                 /* block isn't allocated yet and
1943                                  * user doesn't want to allocate it */
1944                                 goto out2;
1945                         }
1946                         /* we should allocate requested block */
1947                 } else if (goal == EXT4_EXT_CACHE_EXTENT) {
1948                         /* block is already allocated */
1949                         newblock = iblock
1950                                    - le32_to_cpu(newex.ee_block)
1951                                    + ext_pblock(&newex);
1952                         /* number of remaining blocks in the extent */
1953                         allocated = le16_to_cpu(newex.ee_len) -
1954                                         (iblock - le32_to_cpu(newex.ee_block));
1955                         goto out;
1956                 } else {
1957                         BUG();
1958                 }
1959         }
1960
1961         /* find extent for this block */
1962         path = ext4_ext_find_extent(inode, iblock, NULL);
1963         if (IS_ERR(path)) {
1964                 err = PTR_ERR(path);
1965                 path = NULL;
1966                 goto out2;
1967         }
1968
1969         depth = ext_depth(inode);
1970
1971         /*
1972          * consistent leaf must not be empty;
1973          * this situation is possible, though, _during_ tree modification;
1974          * this is why assert can't be put in ext4_ext_find_extent()
1975          */
1976         BUG_ON(path[depth].p_ext == NULL && depth != 0);
1977
1978         if ((ex = path[depth].p_ext)) {
1979                 unsigned long ee_block = le32_to_cpu(ex->ee_block);
1980                 ext4_fsblk_t ee_start = ext_pblock(ex);
1981                 unsigned short ee_len  = le16_to_cpu(ex->ee_len);
1982
1983                 /*
1984                  * Allow future support for preallocated extents to be added
1985                  * as an RO_COMPAT feature:
1986                  * Uninitialized extents are treated as holes, except that
1987                  * we avoid (fail) allocating new blocks during a write.
1988                  */
1989                 if (ee_len > EXT_MAX_LEN)
1990                         goto out2;
1991                 /* if found extent covers block, simply return it */
1992                 if (iblock >= ee_block && iblock < ee_block + ee_len) {
1993                         newblock = iblock - ee_block + ee_start;
1994                         /* number of remaining blocks in the extent */
1995                         allocated = ee_len - (iblock - ee_block);
1996                         ext_debug("%d fit into %lu:%d -> "E3FSBLK"\n", (int) iblock,
1997                                         ee_block, ee_len, newblock);
1998                         ext4_ext_put_in_cache(inode, ee_block, ee_len,
1999                                                 ee_start, EXT4_EXT_CACHE_EXTENT);
2000                         goto out;
2001                 }
2002         }
2003
2004         /*
2005          * requested block isn't allocated yet;
2006          * we couldn't try to create block if create flag is zero
2007          */
2008         if (!create) {
2009                 /* put just found gap into cache to speed up
2010                  * subsequent requests */
2011                 ext4_ext_put_gap_in_cache(inode, path, iblock);
2012                 goto out2;
2013         }
2014         /*
2015          * Okay, we need to do block allocation.  Lazily initialize the block
2016          * allocation info here if necessary.
2017         */
2018         if (S_ISREG(inode->i_mode) && (!EXT4_I(inode)->i_block_alloc_info))
2019                 ext4_init_block_alloc_info(inode);
2020
2021         /* allocate new block */
2022         goal = ext4_ext_find_goal(inode, path, iblock);
2023         allocated = max_blocks;
2024         newblock = ext4_new_blocks(handle, inode, goal, &allocated, &err);
2025         if (!newblock)
2026                 goto out2;
2027         ext_debug("allocate new block: goal "E3FSBLK", found "E3FSBLK"/%lu\n",
2028                         goal, newblock, allocated);
2029
2030         /* try to insert new extent into found leaf and return */
2031         newex.ee_block = cpu_to_le32(iblock);
2032         ext4_ext_store_pblock(&newex, newblock);
2033         newex.ee_len = cpu_to_le16(allocated);
2034         err = ext4_ext_insert_extent(handle, inode, path, &newex);
2035         if (err)
2036                 goto out2;
2037
2038         if (extend_disksize && inode->i_size > EXT4_I(inode)->i_disksize)
2039                 EXT4_I(inode)->i_disksize = inode->i_size;
2040
2041         /* previous routine could use block we allocated */
2042         newblock = ext_pblock(&newex);
2043         __set_bit(BH_New, &bh_result->b_state);
2044
2045         ext4_ext_put_in_cache(inode, iblock, allocated, newblock,
2046                                 EXT4_EXT_CACHE_EXTENT);
2047 out:
2048         if (allocated > max_blocks)
2049                 allocated = max_blocks;
2050         ext4_ext_show_leaf(inode, path);
2051         __set_bit(BH_Mapped, &bh_result->b_state);
2052         bh_result->b_bdev = inode->i_sb->s_bdev;
2053         bh_result->b_blocknr = newblock;
2054 out2:
2055         if (path) {
2056                 ext4_ext_drop_refs(path);
2057                 kfree(path);
2058         }
2059         mutex_unlock(&EXT4_I(inode)->truncate_mutex);
2060
2061         return err ? err : allocated;
2062 }
2063
2064 void ext4_ext_truncate(struct inode * inode, struct page *page)
2065 {
2066         struct address_space *mapping = inode->i_mapping;
2067         struct super_block *sb = inode->i_sb;
2068         unsigned long last_block;
2069         handle_t *handle;
2070         int err = 0;
2071
2072         /*
2073          * probably first extent we're gonna free will be last in block
2074          */
2075         err = ext4_writepage_trans_blocks(inode) + 3;
2076         handle = ext4_journal_start(inode, err);
2077         if (IS_ERR(handle)) {
2078                 if (page) {
2079                         clear_highpage(page);
2080                         flush_dcache_page(page);
2081                         unlock_page(page);
2082                         page_cache_release(page);
2083                 }
2084                 return;
2085         }
2086
2087         if (page)
2088                 ext4_block_truncate_page(handle, page, mapping, inode->i_size);
2089
2090         mutex_lock(&EXT4_I(inode)->truncate_mutex);
2091         ext4_ext_invalidate_cache(inode);
2092
2093         /*
2094          * TODO: optimization is possible here.
2095          * Probably we need not scan at all,
2096          * because page truncation is enough.
2097          */
2098         if (ext4_orphan_add(handle, inode))
2099                 goto out_stop;
2100
2101         /* we have to know where to truncate from in crash case */
2102         EXT4_I(inode)->i_disksize = inode->i_size;
2103         ext4_mark_inode_dirty(handle, inode);
2104
2105         last_block = (inode->i_size + sb->s_blocksize - 1)
2106                         >> EXT4_BLOCK_SIZE_BITS(sb);
2107         err = ext4_ext_remove_space(inode, last_block);
2108
2109         /* In a multi-transaction truncate, we only make the final
2110          * transaction synchronous. */
2111         if (IS_SYNC(inode))
2112                 handle->h_sync = 1;
2113
2114 out_stop:
2115         /*
2116          * If this was a simple ftruncate() and the file will remain alive,
2117          * then we need to clear up the orphan record which we created above.
2118          * However, if this was a real unlink then we were called by
2119          * ext4_delete_inode(), and we allow that function to clean up the
2120          * orphan info for us.
2121          */
2122         if (inode->i_nlink)
2123                 ext4_orphan_del(handle, inode);
2124
2125         mutex_unlock(&EXT4_I(inode)->truncate_mutex);
2126         ext4_journal_stop(handle);
2127 }
2128
2129 /*
2130  * ext4_ext_writepage_trans_blocks:
2131  * calculate max number of blocks we could modify
2132  * in order to allocate new block for an inode
2133  */
2134 int ext4_ext_writepage_trans_blocks(struct inode *inode, int num)
2135 {
2136         int needed;
2137
2138         needed = ext4_ext_calc_credits_for_insert(inode, NULL);
2139
2140         /* caller wants to allocate num blocks, but note it includes sb */
2141         needed = needed * num - (num - 1);
2142
2143 #ifdef CONFIG_QUOTA
2144         needed += 2 * EXT4_QUOTA_TRANS_BLOCKS(inode->i_sb);
2145 #endif
2146
2147         return needed;
2148 }
2149
2150 EXPORT_SYMBOL(ext4_mark_inode_dirty);
2151 EXPORT_SYMBOL(ext4_ext_invalidate_cache);
2152 EXPORT_SYMBOL(ext4_ext_insert_extent);
2153 EXPORT_SYMBOL(ext4_ext_walk_space);
2154 EXPORT_SYMBOL(ext4_ext_find_goal);
2155 EXPORT_SYMBOL(ext4_ext_calc_credits_for_insert);
2156