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/fs.h>
  33 #include <linux/time.h>
  34 #include <linux/jbd2.h>
  35 #include <linux/highuid.h>
  36 #include <linux/pagemap.h>
  37 #include <linux/quotaops.h>
  38 #include <linux/string.h>
  39 #include <linux/slab.h>
  40 #include <linux/falloc.h>
  41 #include <asm/uaccess.h>
  42 #include <linux/fiemap.h>
  43 #include "ext4_jbd2.h"
  44 #include "ext4_extents.h"
  45 #include "xattr.h"
  46
  47 #include <trace/events/ext4.h>
  48
  49 /*
  50  * used by extent splitting.
  51  */
  52 #define EXT4_EXT_MAY_ZEROOUT    0x1  /* safe to zeroout if split fails \
  53                                         due to ENOSPC */
  54 #define EXT4_EXT_MARK_UNINIT1   0x2  /* mark first half uninitialized */
  55 #define EXT4_EXT_MARK_UNINIT2   0x4  /* mark second half uninitialized */
  56
  57 #define EXT4_EXT_DATA_VALID1    0x8  /* first half contains valid data */
  58 #define EXT4_EXT_DATA_VALID2    0x10 /* second half contains valid data */
  59
  60 static __le32 ext4_extent_block_csum(struct inode *inode,
  61                                      struct ext4_extent_header *eh)
  62 {
  63         struct ext4_inode_info *ei = EXT4_I(inode);
  64         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
  65         __u32 csum;
  66
  67         csum = ext4_chksum(sbi, ei->i_csum_seed, (__u8 *)eh,
  68                            EXT4_EXTENT_TAIL_OFFSET(eh));
  69         return cpu_to_le32(csum);
  70 }
  71
  72 static int ext4_extent_block_csum_verify(struct inode *inode,
  73                                          struct ext4_extent_header *eh)
  74 {
  75         struct ext4_extent_tail *et;
  76
  77         if (!EXT4_HAS_RO_COMPAT_FEATURE(inode->i_sb,
  78                 EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
  79                 return 1;
  80
  81         et = find_ext4_extent_tail(eh);
  82         if (et->et_checksum != ext4_extent_block_csum(inode, eh))
  83                 return 0;
  84         return 1;
  85 }
  86
  87 static void ext4_extent_block_csum_set(struct inode *inode,
  88                                        struct ext4_extent_header *eh)
  89 {
  90         struct ext4_extent_tail *et;
  91
  92         if (!EXT4_HAS_RO_COMPAT_FEATURE(inode->i_sb,
  93                 EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
  94                 return;
  95
  96         et = find_ext4_extent_tail(eh);
  97         et->et_checksum = ext4_extent_block_csum(inode, eh);
  98 }
  99
 100 static int ext4_split_extent(handle_t *handle,
 101                                 struct inode *inode,
 102                                 struct ext4_ext_path *path,
 103                                 struct ext4_map_blocks *map,
 104                                 int split_flag,
 105                                 int flags);
 106
 107 static int ext4_split_extent_at(handle_t *handle,
 108                              struct inode *inode,
 109                              struct ext4_ext_path *path,
 110                              ext4_lblk_t split,
 111                              int split_flag,
 112                              int flags);
 113
 114 static int ext4_find_delayed_extent(struct inode *inode,
 115                                     struct extent_status *newes);
 116
 117 static int ext4_ext_truncate_extend_restart(handle_t *handle,
 118                                             struct inode *inode,
 119                                             int needed)
 120 {
 121         int err;
 122
 123         if (!ext4_handle_valid(handle))
 124                 return 0;
 125         if (handle->h_buffer_credits > needed)
 126                 return 0;
 127         err = ext4_journal_extend(handle, needed);
 128         if (err <= 0)
 129                 return err;
 130         err = ext4_truncate_restart_trans(handle, inode, needed);
 131         if (err == 0)
 132                 err = -EAGAIN;
 133
 134         return err;
 135 }
 136
 137 /*
 138  * could return:
 139  *  - EROFS
 140  *  - ENOMEM
 141  */
 142 static int ext4_ext_get_access(handle_t *handle, struct inode *inode,
 143                                 struct ext4_ext_path *path)
 144 {
 145         if (path->p_bh) {
 146                 /* path points to block */
 147                 return ext4_journal_get_write_access(handle, path->p_bh);
 148         }
 149         /* path points to leaf/index in inode body */
 150         /* we use in-core data, no need to protect them */
 151         return 0;
 152 }
 153
 154 /*
 155  * could return:
 156  *  - EROFS
 157  *  - ENOMEM
 158  *  - EIO
 159  */
 160 int __ext4_ext_dirty(const char *where, unsigned int line, handle_t *handle,
 161                      struct inode *inode, struct ext4_ext_path *path)
 162 {
 163         int err;
 164         if (path->p_bh) {
 165                 ext4_extent_block_csum_set(inode, ext_block_hdr(path->p_bh));
 166                 /* path points to block */
 167                 err = __ext4_handle_dirty_metadata(where, line, handle,
 168                                                    inode, path->p_bh);
 169         } else {
 170                 /* path points to leaf/index in inode body */
 171                 err = ext4_mark_inode_dirty(handle, inode);
 172         }
 173         return err;
 174 }
 175
 176 static ext4_fsblk_t ext4_ext_find_goal(struct inode *inode,
 177                               struct ext4_ext_path *path,
 178                               ext4_lblk_t block)
 179 {
 180         if (path) {
 181                 int depth = path->p_depth;
 182                 struct ext4_extent *ex;
 183
 184                 /*
 185                  * Try to predict block placement assuming that we are
 186                  * filling in a file which will eventually be
 187                  * non-sparse --- i.e., in the case of libbfd writing
 188                  * an ELF object sections out-of-order but in a way
 189                  * the eventually results in a contiguous object or
 190                  * executable file, or some database extending a table
 191                  * space file.  However, this is actually somewhat
 192                  * non-ideal if we are writing a sparse file such as
 193                  * qemu or KVM writing a raw image file that is going
 194                  * to stay fairly sparse, since it will end up
 195                  * fragmenting the file system's free space.  Maybe we
 196                  * should have some hueristics or some way to allow
 197                  * userspace to pass a hint to file system,
 198                  * especially if the latter case turns out to be
 199                  * common.
 200                  */
 201                 ex = path[depth].p_ext;
 202                 if (ex) {
 203                         ext4_fsblk_t ext_pblk = ext4_ext_pblock(ex);
 204                         ext4_lblk_t ext_block = le32_to_cpu(ex->ee_block);
 205
 206                         if (block > ext_block)
 207                                 return ext_pblk + (block - ext_block);
 208                         else
 209                                 return ext_pblk - (ext_block - block);
 210                 }
 211
 212                 /* it looks like index is empty;
 213                  * try to find starting block from index itself */
 214                 if (path[depth].p_bh)
 215                         return path[depth].p_bh->b_blocknr;
 216         }
 217
 218         /* OK. use inode's group */
 219         return ext4_inode_to_goal_block(inode);
 220 }
 221
 222 /*
 223  * Allocation for a meta data block
 224  */
 225 static ext4_fsblk_t
 226 ext4_ext_new_meta_block(handle_t *handle, struct inode *inode,
 227                         struct ext4_ext_path *path,
 228                         struct ext4_extent *ex, int *err, unsigned int flags)
 229 {
 230         ext4_fsblk_t goal, newblock;
 231
 232         goal = ext4_ext_find_goal(inode, path, le32_to_cpu(ex->ee_block));
 233         newblock = ext4_new_meta_blocks(handle, inode, goal, flags,
 234                                         NULL, err);
 235         return newblock;
 236 }
 237
 238 static inline int ext4_ext_space_block(struct inode *inode, int check)
 239 {
 240         int size;
 241
 242         size = (inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header))
 243                         / sizeof(struct ext4_extent);
 244 #ifdef AGGRESSIVE_TEST
 245         if (!check && size > 6)
 246                 size = 6;
 247 #endif
 248         return size;
 249 }
 250
 251 static inline int ext4_ext_space_block_idx(struct inode *inode, int check)
 252 {
 253         int size;
 254
 255         size = (inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header))
 256                         / sizeof(struct ext4_extent_idx);
 257 #ifdef AGGRESSIVE_TEST
 258         if (!check && size > 5)
 259                 size = 5;
 260 #endif
 261         return size;
 262 }
 263
 264 static inline int ext4_ext_space_root(struct inode *inode, int check)
 265 {
 266         int size;
 267
 268         size = sizeof(EXT4_I(inode)->i_data);
 269         size -= sizeof(struct ext4_extent_header);
 270         size /= sizeof(struct ext4_extent);
 271 #ifdef AGGRESSIVE_TEST
 272         if (!check && size > 3)
 273                 size = 3;
 274 #endif
 275         return size;
 276 }
 277
 278 static inline int ext4_ext_space_root_idx(struct inode *inode, int check)
 279 {
 280         int size;
 281
 282         size = sizeof(EXT4_I(inode)->i_data);
 283         size -= sizeof(struct ext4_extent_header);
 284         size /= sizeof(struct ext4_extent_idx);
 285 #ifdef AGGRESSIVE_TEST
 286         if (!check && size > 4)
 287                 size = 4;
 288 #endif
 289         return size;
 290 }
 291
 292 /*
 293  * Calculate the number of metadata blocks needed
 294  * to allocate @blocks
 295  * Worse case is one block per extent
 296  */
 297 int ext4_ext_calc_metadata_amount(struct inode *inode, ext4_lblk_t lblock)
 298 {
 299         struct ext4_inode_info *ei = EXT4_I(inode);
 300         int idxs;
 301
 302         idxs = ((inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header))
 303                 / sizeof(struct ext4_extent_idx));
 304
 305         /*
 306          * If the new delayed allocation block is contiguous with the
 307          * previous da block, it can share index blocks with the
 308          * previous block, so we only need to allocate a new index
 309          * block every idxs leaf blocks.  At ldxs**2 blocks, we need
 310          * an additional index block, and at ldxs**3 blocks, yet
 311          * another index blocks.
 312          */
 313         if (ei->i_da_metadata_calc_len &&
 314             ei->i_da_metadata_calc_last_lblock+1 == lblock) {
 315                 int num = 0;
 316
 317                 if ((ei->i_da_metadata_calc_len % idxs) == 0)
 318                         num++;
 319                 if ((ei->i_da_metadata_calc_len % (idxs*idxs)) == 0)
 320                         num++;
 321                 if ((ei->i_da_metadata_calc_len % (idxs*idxs*idxs)) == 0) {
 322                         num++;
 323                         ei->i_da_metadata_calc_len = 0;
 324                 } else
 325                         ei->i_da_metadata_calc_len++;
 326                 ei->i_da_metadata_calc_last_lblock++;
 327                 return num;
 328         }
 329
 330         /*
 331          * In the worst case we need a new set of index blocks at
 332          * every level of the inode's extent tree.
 333          */
 334         ei->i_da_metadata_calc_len = 1;
 335         ei->i_da_metadata_calc_last_lblock = lblock;
 336         return ext_depth(inode) + 1;
 337 }
 338
 339 static int
 340 ext4_ext_max_entries(struct inode *inode, int depth)
 341 {
 342         int max;
 343
 344         if (depth == ext_depth(inode)) {
 345                 if (depth == 0)
 346                         max = ext4_ext_space_root(inode, 1);
 347                 else
 348                         max = ext4_ext_space_root_idx(inode, 1);
 349         } else {
 350                 if (depth == 0)
 351                         max = ext4_ext_space_block(inode, 1);
 352                 else
 353                         max = ext4_ext_space_block_idx(inode, 1);
 354         }
 355
 356         return max;
 357 }
 358
 359 static int ext4_valid_extent(struct inode *inode, struct ext4_extent *ext)
 360 {
 361         ext4_fsblk_t block = ext4_ext_pblock(ext);
 362         int len = ext4_ext_get_actual_len(ext);
 363
 364         if (len == 0)
 365                 return 0;
 366         return ext4_data_block_valid(EXT4_SB(inode->i_sb), block, len);
 367 }
 368
 369 static int ext4_valid_extent_idx(struct inode *inode,
 370                                 struct ext4_extent_idx *ext_idx)
 371 {
 372         ext4_fsblk_t block = ext4_idx_pblock(ext_idx);
 373
 374         return ext4_data_block_valid(EXT4_SB(inode->i_sb), block, 1);
 375 }
 376
 377 static int ext4_valid_extent_entries(struct inode *inode,
 378                                 struct ext4_extent_header *eh,
 379                                 int depth)
 380 {
 381         unsigned short entries;
 382         if (eh->eh_entries == 0)
 383                 return 1;
 384
 385         entries = le16_to_cpu(eh->eh_entries);
 386
 387         if (depth == 0) {
 388                 /* leaf entries */
 389                 struct ext4_extent *ext = EXT_FIRST_EXTENT(eh);
 390                 while (entries) {
 391                         if (!ext4_valid_extent(inode, ext))
 392                                 return 0;
 393                         ext++;
 394                         entries--;
 395                 }
 396         } else {
 397                 struct ext4_extent_idx *ext_idx = EXT_FIRST_INDEX(eh);
 398                 while (entries) {
 399                         if (!ext4_valid_extent_idx(inode, ext_idx))
 400                                 return 0;
 401                         ext_idx++;
 402                         entries--;
 403                 }
 404         }
 405         return 1;
 406 }
 407
 408 static int __ext4_ext_check(const char *function, unsigned int line,
 409                             struct inode *inode, struct ext4_extent_header *eh,
 410                             int depth, ext4_fsblk_t pblk)
 411 {
 412         const char *error_msg;
 413         int max = 0;
 414
 415         if (unlikely(eh->eh_magic != EXT4_EXT_MAGIC)) {
 416                 error_msg = "invalid magic";
 417                 goto corrupted;
 418         }
 419         if (unlikely(le16_to_cpu(eh->eh_depth) != depth)) {
 420                 error_msg = "unexpected eh_depth";
 421                 goto corrupted;
 422         }
 423         if (unlikely(eh->eh_max == 0)) {
 424                 error_msg = "invalid eh_max";
 425                 goto corrupted;
 426         }
 427         max = ext4_ext_max_entries(inode, depth);
 428         if (unlikely(le16_to_cpu(eh->eh_max) > max)) {
 429                 error_msg = "too large eh_max";
 430                 goto corrupted;
 431         }
 432         if (unlikely(le16_to_cpu(eh->eh_entries) > le16_to_cpu(eh->eh_max))) {
 433                 error_msg = "invalid eh_entries";
 434                 goto corrupted;
 435         }
 436         if (!ext4_valid_extent_entries(inode, eh, depth)) {
 437                 error_msg = "invalid extent entries";
 438                 goto corrupted;
 439         }
 440         /* Verify checksum on non-root extent tree nodes */
 441         if (ext_depth(inode) != depth &&
 442             !ext4_extent_block_csum_verify(inode, eh)) {
 443                 error_msg = "extent tree corrupted";
 444                 goto corrupted;
 445         }
 446         return 0;
 447
 448 corrupted:
 449         ext4_error_inode(inode, function, line, 0,
 450                          "pblk %llu bad header/extent: %s - magic %x, "
 451                          "entries %u, max %u(%u), depth %u(%u)",
 452                          (unsigned long long) pblk, error_msg,
 453                          le16_to_cpu(eh->eh_magic),
 454                          le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max),
 455                          max, le16_to_cpu(eh->eh_depth), depth);
 456         return -EIO;
 457 }
 458
 459 #define ext4_ext_check(inode, eh, depth, pblk)                  \
 460         __ext4_ext_check(__func__, __LINE__, (inode), (eh), (depth), (pblk))
 461
 462 int ext4_ext_check_inode(struct inode *inode)
 463 {
 464         return ext4_ext_check(inode, ext_inode_hdr(inode), ext_depth(inode), 0);
 465 }
 466
 467 static struct buffer_head *
 468 __read_extent_tree_block(const char *function, unsigned int line,
 469                          struct inode *inode, ext4_fsblk_t pblk, int depth,
 470                          int flags)
 471 {
 472         struct buffer_head              *bh;
 473         int                             err;
 474
 475         bh = sb_getblk(inode->i_sb, pblk);
 476         if (unlikely(!bh))
 477                 return ERR_PTR(-ENOMEM);
 478
 479         if (!bh_uptodate_or_lock(bh)) {
 480                 trace_ext4_ext_load_extent(inode, pblk, _RET_IP_);
 481                 err = bh_submit_read(bh);
 482                 if (err < 0)
 483                         goto errout;
 484         }
 485         if (buffer_verified(bh) && !(flags & EXT4_EX_FORCE_CACHE))
 486                 return bh;
 487         err = __ext4_ext_check(function, line, inode,
 488                                ext_block_hdr(bh), depth, pblk);
 489         if (err)
 490                 goto errout;
 491         set_buffer_verified(bh);
 492         /*
 493          * If this is a leaf block, cache all of its entries
 494          */
 495         if (!(flags & EXT4_EX_NOCACHE) && depth == 0) {
 496                 struct ext4_extent_header *eh = ext_block_hdr(bh);
 497                 struct ext4_extent *ex = EXT_FIRST_EXTENT(eh);
 498                 ext4_lblk_t prev = 0;
 499                 int i;
 500
 501                 for (i = le16_to_cpu(eh->eh_entries); i > 0; i--, ex++) {
 502                         unsigned int status = EXTENT_STATUS_WRITTEN;
 503                         ext4_lblk_t lblk = le32_to_cpu(ex->ee_block);
 504                         int len = ext4_ext_get_actual_len(ex);
 505
 506                         if (prev && (prev != lblk))
 507                                 ext4_es_cache_extent(inode, prev,
 508                                                      lblk - prev, ~0,
 509                                                      EXTENT_STATUS_HOLE);
 510
 511                         if (ext4_ext_is_uninitialized(ex))
 512                                 status = EXTENT_STATUS_UNWRITTEN;
 513                         ext4_es_cache_extent(inode, lblk, len,
 514                                              ext4_ext_pblock(ex), status);
 515                         prev = lblk + len;
 516                 }
 517         }
 518         return bh;
 519 errout:
 520         put_bh(bh);
 521         return ERR_PTR(err);
 522
 523 }
 524
 525 #define read_extent_tree_block(inode, pblk, depth, flags)               \
 526         __read_extent_tree_block(__func__, __LINE__, (inode), (pblk),   \
 527                                  (depth), (flags))
 528
 529 /*
 530  * This function is called to cache a file's extent information in the
 531  * extent status tree
 532  */
 533 int ext4_ext_precache(struct inode *inode)
 534 {
 535         struct ext4_inode_info *ei = EXT4_I(inode);
 536         struct ext4_ext_path *path = NULL;
 537         struct buffer_head *bh;
 538         int i = 0, depth, ret = 0;
 539
 540         if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
 541                 return 0;       /* not an extent-mapped inode */
 542
 543         down_read(&ei->i_data_sem);
 544         depth = ext_depth(inode);
 545
 546         path = kzalloc(sizeof(struct ext4_ext_path) * (depth + 1),
 547                        GFP_NOFS);
 548         if (path == NULL) {
 549                 up_read(&ei->i_data_sem);
 550                 return -ENOMEM;
 551         }
 552
 553         /* Don't cache anything if there are no external extent blocks */
 554         if (depth == 0)
 555                 goto out;
 556         path[0].p_hdr = ext_inode_hdr(inode);
 557         ret = ext4_ext_check(inode, path[0].p_hdr, depth, 0);
 558         if (ret)
 559                 goto out;
 560         path[0].p_idx = EXT_FIRST_INDEX(path[0].p_hdr);
 561         while (i >= 0) {
 562                 /*
 563                  * If this is a leaf block or we've reached the end of
 564                  * the index block, go up
 565                  */
 566                 if ((i == depth) ||
 567                     path[i].p_idx > EXT_LAST_INDEX(path[i].p_hdr)) {
 568                         brelse(path[i].p_bh);
 569                         path[i].p_bh = NULL;
 570                         i--;
 571                         continue;
 572                 }
 573                 bh = read_extent_tree_block(inode,
 574                                             ext4_idx_pblock(path[i].p_idx++),
 575                                             depth - i - 1,
 576                                             EXT4_EX_FORCE_CACHE);
 577                 if (IS_ERR(bh)) {
 578                         ret = PTR_ERR(bh);
 579                         break;
 580                 }
 581                 i++;
 582                 path[i].p_bh = bh;
 583                 path[i].p_hdr = ext_block_hdr(bh);
 584                 path[i].p_idx = EXT_FIRST_INDEX(path[i].p_hdr);
 585         }
 586         ext4_set_inode_state(inode, EXT4_STATE_EXT_PRECACHED);
 587 out:
 588         up_read(&ei->i_data_sem);
 589         ext4_ext_drop_refs(path);
 590         kfree(path);
 591         return ret;
 592 }
 593
 594 #ifdef EXT_DEBUG
 595 static void ext4_ext_show_path(struct inode *inode, struct ext4_ext_path *path)
 596 {
 597         int k, l = path->p_depth;
 598
 599         ext_debug("path:");
 600         for (k = 0; k <= l; k++, path++) {
 601                 if (path->p_idx) {
 602                   ext_debug("  %d->%llu", le32_to_cpu(path->p_idx->ei_block),
 603                             ext4_idx_pblock(path->p_idx));
 604                 } else if (path->p_ext) {
 605                         ext_debug("  %d:[%d]%d:%llu ",
 606                                   le32_to_cpu(path->p_ext->ee_block),
 607                                   ext4_ext_is_uninitialized(path->p_ext),
 608                                   ext4_ext_get_actual_len(path->p_ext),
 609                                   ext4_ext_pblock(path->p_ext));
 610                 } else
 611                         ext_debug("  []");
 612         }
 613         ext_debug("\n");
 614 }
 615
 616 static void ext4_ext_show_leaf(struct inode *inode, struct ext4_ext_path *path)
 617 {
 618         int depth = ext_depth(inode);
 619         struct ext4_extent_header *eh;
 620         struct ext4_extent *ex;
 621         int i;
 622
 623         if (!path)
 624                 return;
 625
 626         eh = path[depth].p_hdr;
 627         ex = EXT_FIRST_EXTENT(eh);
 628
 629         ext_debug("Displaying leaf extents for inode %lu\n", inode->i_ino);
 630
 631         for (i = 0; i < le16_to_cpu(eh->eh_entries); i++, ex++) {
 632                 ext_debug("%d:[%d]%d:%llu ", le32_to_cpu(ex->ee_block),
 633                           ext4_ext_is_uninitialized(ex),
 634                           ext4_ext_get_actual_len(ex), ext4_ext_pblock(ex));
 635         }
 636         ext_debug("\n");
 637 }
 638
 639 static void ext4_ext_show_move(struct inode *inode, struct ext4_ext_path *path,
 640                         ext4_fsblk_t newblock, int level)
 641 {
 642         int depth = ext_depth(inode);
 643         struct ext4_extent *ex;
 644
 645         if (depth != level) {
 646                 struct ext4_extent_idx *idx;
 647                 idx = path[level].p_idx;
 648                 while (idx <= EXT_MAX_INDEX(path[level].p_hdr)) {
 649                         ext_debug("%d: move %d:%llu in new index %llu\n", level,
 650                                         le32_to_cpu(idx->ei_block),
 651                                         ext4_idx_pblock(idx),
 652                                         newblock);
 653                         idx++;
 654                 }
 655
 656                 return;
 657         }
 658
 659         ex = path[depth].p_ext;
 660         while (ex <= EXT_MAX_EXTENT(path[depth].p_hdr)) {
 661                 ext_debug("move %d:%llu:[%d]%d in new leaf %llu\n",
 662                                 le32_to_cpu(ex->ee_block),
 663                                 ext4_ext_pblock(ex),
 664                                 ext4_ext_is_uninitialized(ex),
 665                                 ext4_ext_get_actual_len(ex),
 666                                 newblock);
 667                 ex++;
 668         }
 669 }
 670
 671 #else
 672 #define ext4_ext_show_path(inode, path)
 673 #define ext4_ext_show_leaf(inode, path)
 674 #define ext4_ext_show_move(inode, path, newblock, level)
 675 #endif
 676
 677 void ext4_ext_drop_refs(struct ext4_ext_path *path)
 678 {
 679         int depth = path->p_depth;
 680         int i;
 681
 682         for (i = 0; i <= depth; i++, path++)
 683                 if (path->p_bh) {
 684                         brelse(path->p_bh);
 685                         path->p_bh = NULL;
 686                 }
 687 }
 688
 689 /*
 690  * ext4_ext_binsearch_idx:
 691  * binary search for the closest index of the given block
 692  * the header must be checked before calling this
 693  */
 694 static void
 695 ext4_ext_binsearch_idx(struct inode *inode,
 696                         struct ext4_ext_path *path, ext4_lblk_t block)
 697 {
 698         struct ext4_extent_header *eh = path->p_hdr;
 699         struct ext4_extent_idx *r, *l, *m;
 700
 701
 702         ext_debug("binsearch for %u(idx):  ", block);
 703
 704         l = EXT_FIRST_INDEX(eh) + 1;
 705         r = EXT_LAST_INDEX(eh);
 706         while (l <= r) {
 707                 m = l + (r - l) / 2;
 708                 if (block < le32_to_cpu(m->ei_block))
 709                         r = m - 1;
 710                 else
 711                         l = m + 1;
 712                 ext_debug("%p(%u):%p(%u):%p(%u) ", l, le32_to_cpu(l->ei_block),
 713                                 m, le32_to_cpu(m->ei_block),
 714                                 r, le32_to_cpu(r->ei_block));
 715         }
 716
 717         path->p_idx = l - 1;
 718         ext_debug("  -> %u->%lld ", le32_to_cpu(path->p_idx->ei_block),
 719                   ext4_idx_pblock(path->p_idx));
 720
 721 #ifdef CHECK_BINSEARCH
 722         {
 723                 struct ext4_extent_idx *chix, *ix;
 724                 int k;
 725
 726                 chix = ix = EXT_FIRST_INDEX(eh);
 727                 for (k = 0; k < le16_to_cpu(eh->eh_entries); k++, ix++) {
 728                   if (k != 0 &&
 729                       le32_to_cpu(ix->ei_block) <= le32_to_cpu(ix[-1].ei_block)) {
 730                                 printk(KERN_DEBUG "k=%d, ix=0x%p, "
 731                                        "first=0x%p\n", k,
 732                                        ix, EXT_FIRST_INDEX(eh));
 733                                 printk(KERN_DEBUG "%u <= %u\n",
 734                                        le32_to_cpu(ix->ei_block),
 735                                        le32_to_cpu(ix[-1].ei_block));
 736                         }
 737                         BUG_ON(k && le32_to_cpu(ix->ei_block)
 738                                            <= le32_to_cpu(ix[-1].ei_block));
 739                         if (block < le32_to_cpu(ix->ei_block))
 740                                 break;
 741                         chix = ix;
 742                 }
 743                 BUG_ON(chix != path->p_idx);
 744         }
 745 #endif
 746
 747 }
 748
 749 /*
 750  * ext4_ext_binsearch:
 751  * binary search for closest extent of the given block
 752  * the header must be checked before calling this
 753  */
 754 static void
 755 ext4_ext_binsearch(struct inode *inode,
 756                 struct ext4_ext_path *path, ext4_lblk_t block)
 757 {
 758         struct ext4_extent_header *eh = path->p_hdr;
 759         struct ext4_extent *r, *l, *m;
 760
 761         if (eh->eh_entries == 0) {
 762                 /*
 763                  * this leaf is empty:
 764                  * we get such a leaf in split/add case
 765                  */
 766                 return;
 767         }
 768
 769         ext_debug("binsearch for %u:  ", block);
 770
 771         l = EXT_FIRST_EXTENT(eh) + 1;
 772         r = EXT_LAST_EXTENT(eh);
 773
 774         while (l <= r) {
 775                 m = l + (r - l) / 2;
 776                 if (block < le32_to_cpu(m->ee_block))
 777                         r = m - 1;
 778                 else
 779                         l = m + 1;
 780                 ext_debug("%p(%u):%p(%u):%p(%u) ", l, le32_to_cpu(l->ee_block),
 781                                 m, le32_to_cpu(m->ee_block),
 782                                 r, le32_to_cpu(r->ee_block));
 783         }
 784
 785         path->p_ext = l - 1;
 786         ext_debug("  -> %d:%llu:[%d]%d ",
 787                         le32_to_cpu(path->p_ext->ee_block),
 788                         ext4_ext_pblock(path->p_ext),
 789                         ext4_ext_is_uninitialized(path->p_ext),
 790                         ext4_ext_get_actual_len(path->p_ext));
 791
 792 #ifdef CHECK_BINSEARCH
 793         {
 794                 struct ext4_extent *chex, *ex;
 795                 int k;
 796
 797                 chex = ex = EXT_FIRST_EXTENT(eh);
 798                 for (k = 0; k < le16_to_cpu(eh->eh_entries); k++, ex++) {
 799                         BUG_ON(k && le32_to_cpu(ex->ee_block)
 800                                           <= le32_to_cpu(ex[-1].ee_block));
 801                         if (block < le32_to_cpu(ex->ee_block))
 802                                 break;
 803                         chex = ex;
 804                 }
 805                 BUG_ON(chex != path->p_ext);
 806         }
 807 #endif
 808
 809 }
 810
 811 int ext4_ext_tree_init(handle_t *handle, struct inode *inode)
 812 {
 813         struct ext4_extent_header *eh;
 814
 815         eh = ext_inode_hdr(inode);
 816         eh->eh_depth = 0;
 817         eh->eh_entries = 0;
 818         eh->eh_magic = EXT4_EXT_MAGIC;
 819         eh->eh_max = cpu_to_le16(ext4_ext_space_root(inode, 0));
 820         ext4_mark_inode_dirty(handle, inode);
 821         return 0;
 822 }
 823
 824 struct ext4_ext_path *
 825 ext4_ext_find_extent(struct inode *inode, ext4_lblk_t block,
 826                      struct ext4_ext_path *path, int flags)
 827 {
 828         struct ext4_extent_header *eh;
 829         struct buffer_head *bh;
 830         short int depth, i, ppos = 0, alloc = 0;
 831         int ret;
 832
 833         eh = ext_inode_hdr(inode);
 834         depth = ext_depth(inode);
 835
 836         /* account possible depth increase */
 837         if (!path) {
 838                 path = kzalloc(sizeof(struct ext4_ext_path) * (depth + 2),
 839                                 GFP_NOFS);
 840                 if (!path)
 841                         return ERR_PTR(-ENOMEM);
 842                 alloc = 1;
 843         }
 844         path[0].p_hdr = eh;
 845         path[0].p_bh = NULL;
 846
 847         i = depth;
 848         /* walk through the tree */
 849         while (i) {
 850                 ext_debug("depth %d: num %d, max %d\n",
 851                           ppos, le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max));
 852
 853                 ext4_ext_binsearch_idx(inode, path + ppos, block);
 854                 path[ppos].p_block = ext4_idx_pblock(path[ppos].p_idx);
 855                 path[ppos].p_depth = i;
 856                 path[ppos].p_ext = NULL;
 857
 858                 bh = read_extent_tree_block(inode, path[ppos].p_block, --i,
 859                                             flags);
 860                 if (IS_ERR(bh)) {
 861                         ret = PTR_ERR(bh);
 862                         goto err;
 863                 }
 864
 865                 eh = ext_block_hdr(bh);
 866                 ppos++;
 867                 if (unlikely(ppos > depth)) {
 868                         put_bh(bh);
 869                         EXT4_ERROR_INODE(inode,
 870                                          "ppos %d > depth %d", ppos, depth);
 871                         ret = -EIO;
 872                         goto err;
 873                 }
 874                 path[ppos].p_bh = bh;
 875                 path[ppos].p_hdr = eh;
 876         }
 877
 878         path[ppos].p_depth = i;
 879         path[ppos].p_ext = NULL;
 880         path[ppos].p_idx = NULL;
 881
 882         /* find extent */
 883         ext4_ext_binsearch(inode, path + ppos, block);
 884         /* if not an empty leaf */
 885         if (path[ppos].p_ext)
 886                 path[ppos].p_block = ext4_ext_pblock(path[ppos].p_ext);
 887
 888         ext4_ext_show_path(inode, path);
 889
 890         return path;
 891
 892 err:
 893         ext4_ext_drop_refs(path);
 894         if (alloc)
 895                 kfree(path);
 896         return ERR_PTR(ret);
 897 }
 898
 899 /*
 900  * ext4_ext_insert_index:
 901  * insert new index [@logical;@ptr] into the block at @curp;
 902  * check where to insert: before @curp or after @curp
 903  */
 904 static int ext4_ext_insert_index(handle_t *handle, struct inode *inode,
 905                                  struct ext4_ext_path *curp,
 906                                  int logical, ext4_fsblk_t ptr)
 907 {
 908         struct ext4_extent_idx *ix;
 909         int len, err;
 910
 911         err = ext4_ext_get_access(handle, inode, curp);
 912         if (err)
 913                 return err;
 914
 915         if (unlikely(logical == le32_to_cpu(curp->p_idx->ei_block))) {
 916                 EXT4_ERROR_INODE(inode,
 917                                  "logical %d == ei_block %d!",
 918                                  logical, le32_to_cpu(curp->p_idx->ei_block));
 919                 return -EIO;
 920         }
 921
 922         if (unlikely(le16_to_cpu(curp->p_hdr->eh_entries)
 923                              >= le16_to_cpu(curp->p_hdr->eh_max))) {
 924                 EXT4_ERROR_INODE(inode,
 925                                  "eh_entries %d >= eh_max %d!",
 926                                  le16_to_cpu(curp->p_hdr->eh_entries),
 927                                  le16_to_cpu(curp->p_hdr->eh_max));
 928                 return -EIO;
 929         }
 930
 931         if (logical > le32_to_cpu(curp->p_idx->ei_block)) {
 932                 /* insert after */
 933                 ext_debug("insert new index %d after: %llu\n", logical, ptr);
 934                 ix = curp->p_idx + 1;
 935         } else {
 936                 /* insert before */
 937                 ext_debug("insert new index %d before: %llu\n", logical, ptr);
 938                 ix = curp->p_idx;
 939         }
 940
 941         len = EXT_LAST_INDEX(curp->p_hdr) - ix + 1;
 942         BUG_ON(len < 0);
 943         if (len > 0) {
 944                 ext_debug("insert new index %d: "
 945                                 "move %d indices from 0x%p to 0x%p\n",
 946                                 logical, len, ix, ix + 1);
 947                 memmove(ix + 1, ix, len * sizeof(struct ext4_extent_idx));
 948         }
 949
 950         if (unlikely(ix > EXT_MAX_INDEX(curp->p_hdr))) {
 951                 EXT4_ERROR_INODE(inode, "ix > EXT_MAX_INDEX!");
 952                 return -EIO;
 953         }
 954
 955         ix->ei_block = cpu_to_le32(logical);
 956         ext4_idx_store_pblock(ix, ptr);
 957         le16_add_cpu(&curp->p_hdr->eh_entries, 1);
 958
 959         if (unlikely(ix > EXT_LAST_INDEX(curp->p_hdr))) {
 960                 EXT4_ERROR_INODE(inode, "ix > EXT_LAST_INDEX!");
 961                 return -EIO;
 962         }
 963
 964         err = ext4_ext_dirty(handle, inode, curp);
 965         ext4_std_error(inode->i_sb, err);
 966
 967         return err;
 968 }
 969
 970 /*
 971  * ext4_ext_split:
 972  * inserts new subtree into the path, using free index entry
 973  * at depth @at:
 974  * - allocates all needed blocks (new leaf and all intermediate index blocks)
 975  * - makes decision where to split
 976  * - moves remaining extents and index entries (right to the split point)
 977  *   into the newly allocated blocks
 978  * - initializes subtree
 979  */
 980 static int ext4_ext_split(handle_t *handle, struct inode *inode,
 981                           unsigned int flags,
 982                           struct ext4_ext_path *path,
 983                           struct ext4_extent *newext, int at)
 984 {
 985         struct buffer_head *bh = NULL;
 986         int depth = ext_depth(inode);
 987         struct ext4_extent_header *neh;
 988         struct ext4_extent_idx *fidx;
 989         int i = at, k, m, a;
 990         ext4_fsblk_t newblock, oldblock;
 991         __le32 border;
 992         ext4_fsblk_t *ablocks = NULL; /* array of allocated blocks */
 993         int err = 0;
 994
 995         /* make decision: where to split? */
 996         /* FIXME: now decision is simplest: at current extent */
 997
 998         /* if current leaf will be split, then we should use
 999          * border from split point */
1000         if (unlikely(path[depth].p_ext > EXT_MAX_EXTENT(path[depth].p_hdr))) {
1001                 EXT4_ERROR_INODE(inode, "p_ext > EXT_MAX_EXTENT!");
1002                 return -EIO;
1003         }
1004         if (path[depth].p_ext != EXT_MAX_EXTENT(path[depth].p_hdr)) {
1005                 border = path[depth].p_ext[1].ee_block;
1006                 ext_debug("leaf will be split."
1007                                 " next leaf starts at %d\n",
1008                                   le32_to_cpu(border));
1009         } else {
1010                 border = newext->ee_block;
1011                 ext_debug("leaf will be added."
1012                                 " next leaf starts at %d\n",
1013                                 le32_to_cpu(border));
1014         }
1015
1016         /*
1017          * If error occurs, then we break processing
1018          * and mark filesystem read-only. index won't
1019          * be inserted and tree will be in consistent
1020          * state. Next mount will repair buffers too.
1021          */
1022
1023         /*
1024          * Get array to track all allocated blocks.
1025          * We need this to handle errors and free blocks
1026          * upon them.
1027          */
1028         ablocks = kzalloc(sizeof(ext4_fsblk_t) * depth, GFP_NOFS);
1029         if (!ablocks)
1030                 return -ENOMEM;
1031
1032         /* allocate all needed blocks */
1033         ext_debug("allocate %d blocks for indexes/leaf\n", depth - at);
1034         for (a = 0; a < depth - at; a++) {
1035                 newblock = ext4_ext_new_meta_block(handle, inode, path,
1036                                                    newext, &err, flags);
1037                 if (newblock == 0)
1038                         goto cleanup;
1039                 ablocks[a] = newblock;
1040         }
1041
1042         /* initialize new leaf */
1043         newblock = ablocks[--a];
1044         if (unlikely(newblock == 0)) {
1045                 EXT4_ERROR_INODE(inode, "newblock == 0!");
1046                 err = -EIO;
1047                 goto cleanup;
1048         }
1049         bh = sb_getblk(inode->i_sb, newblock);
1050         if (unlikely(!bh)) {
1051                 err = -ENOMEM;
1052                 goto cleanup;
1053         }
1054         lock_buffer(bh);
1055
1056         err = ext4_journal_get_create_access(handle, bh);
1057         if (err)
1058                 goto cleanup;
1059
1060         neh = ext_block_hdr(bh);
1061         neh->eh_entries = 0;
1062         neh->eh_max = cpu_to_le16(ext4_ext_space_block(inode, 0));
1063         neh->eh_magic = EXT4_EXT_MAGIC;
1064         neh->eh_depth = 0;
1065
1066         /* move remainder of path[depth] to the new leaf */
1067         if (unlikely(path[depth].p_hdr->eh_entries !=
1068                      path[depth].p_hdr->eh_max)) {
1069                 EXT4_ERROR_INODE(inode, "eh_entries %d != eh_max %d!",
1070                                  path[depth].p_hdr->eh_entries,
1071                                  path[depth].p_hdr->eh_max);
1072                 err = -EIO;
1073                 goto cleanup;
1074         }
1075         /* start copy from next extent */
1076         m = EXT_MAX_EXTENT(path[depth].p_hdr) - path[depth].p_ext++;
1077         ext4_ext_show_move(inode, path, newblock, depth);
1078         if (m) {
1079                 struct ext4_extent *ex;
1080                 ex = EXT_FIRST_EXTENT(neh);
1081                 memmove(ex, path[depth].p_ext, sizeof(struct ext4_extent) * m);
1082                 le16_add_cpu(&neh->eh_entries, m);
1083         }
1084
1085         ext4_extent_block_csum_set(inode, neh);
1086         set_buffer_uptodate(bh);
1087         unlock_buffer(bh);
1088
1089         err = ext4_handle_dirty_metadata(handle, inode, bh);
1090         if (err)
1091                 goto cleanup;
1092         brelse(bh);
1093         bh = NULL;
1094
1095         /* correct old leaf */
1096         if (m) {
1097                 err = ext4_ext_get_access(handle, inode, path + depth);
1098                 if (err)
1099                         goto cleanup;
1100                 le16_add_cpu(&path[depth].p_hdr->eh_entries, -m);
1101                 err = ext4_ext_dirty(handle, inode, path + depth);
1102                 if (err)
1103                         goto cleanup;
1104
1105         }
1106
1107         /* create intermediate indexes */
1108         k = depth - at - 1;
1109         if (unlikely(k < 0)) {
1110                 EXT4_ERROR_INODE(inode, "k %d < 0!", k);
1111                 err = -EIO;
1112                 goto cleanup;
1113         }
1114         if (k)
1115                 ext_debug("create %d intermediate indices\n", k);
1116         /* insert new index into current index block */
1117         /* current depth stored in i var */
1118         i = depth - 1;
1119         while (k--) {
1120                 oldblock = newblock;
1121                 newblock = ablocks[--a];
1122                 bh = sb_getblk(inode->i_sb, newblock);
1123                 if (unlikely(!bh)) {
1124                         err = -ENOMEM;
1125                         goto cleanup;
1126                 }
1127                 lock_buffer(bh);
1128
1129                 err = ext4_journal_get_create_access(handle, bh);
1130                 if (err)
1131                         goto cleanup;
1132
1133                 neh = ext_block_hdr(bh);
1134                 neh->eh_entries = cpu_to_le16(1);
1135                 neh->eh_magic = EXT4_EXT_MAGIC;
1136                 neh->eh_max = cpu_to_le16(ext4_ext_space_block_idx(inode, 0));
1137                 neh->eh_depth = cpu_to_le16(depth - i);
1138                 fidx = EXT_FIRST_INDEX(neh);
1139                 fidx->ei_block = border;
1140                 ext4_idx_store_pblock(fidx, oldblock);
1141
1142                 ext_debug("int.index at %d (block %llu): %u -> %llu\n",
1143                                 i, newblock, le32_to_cpu(border), oldblock);
1144
1145                 /* move remainder of path[i] to the new index block */
1146                 if (unlikely(EXT_MAX_INDEX(path[i].p_hdr) !=
1147                                         EXT_LAST_INDEX(path[i].p_hdr))) {
1148                         EXT4_ERROR_INODE(inode,
1149                                          "EXT_MAX_INDEX != EXT_LAST_INDEX ee_block %d!",
1150                                          le32_to_cpu(path[i].p_ext->ee_block));
1151                         err = -EIO;
1152                         goto cleanup;
1153                 }
1154                 /* start copy indexes */
1155                 m = EXT_MAX_INDEX(path[i].p_hdr) - path[i].p_idx++;
1156                 ext_debug("cur 0x%p, last 0x%p\n", path[i].p_idx,
1157                                 EXT_MAX_INDEX(path[i].p_hdr));
1158                 ext4_ext_show_move(inode, path, newblock, i);
1159                 if (m) {
1160                         memmove(++fidx, path[i].p_idx,
1161                                 sizeof(struct ext4_extent_idx) * m);
1162                         le16_add_cpu(&neh->eh_entries, m);
1163                 }
1164                 ext4_extent_block_csum_set(inode, neh);
1165                 set_buffer_uptodate(bh);
1166                 unlock_buffer(bh);
1167
1168                 err = ext4_handle_dirty_metadata(handle, inode, bh);
1169                 if (err)
1170                         goto cleanup;
1171                 brelse(bh);
1172                 bh = NULL;
1173
1174                 /* correct old index */
1175                 if (m) {
1176                         err = ext4_ext_get_access(handle, inode, path + i);
1177                         if (err)
1178                                 goto cleanup;
1179                         le16_add_cpu(&path[i].p_hdr->eh_entries, -m);
1180                         err = ext4_ext_dirty(handle, inode, path + i);
1181                         if (err)
1182                                 goto cleanup;
1183                 }
1184
1185                 i--;
1186         }
1187
1188         /* insert new index */
1189         err = ext4_ext_insert_index(handle, inode, path + at,
1190                                     le32_to_cpu(border), newblock);
1191
1192 cleanup:
1193         if (bh) {
1194                 if (buffer_locked(bh))
1195                         unlock_buffer(bh);
1196                 brelse(bh);
1197         }
1198
1199         if (err) {
1200                 /* free all allocated blocks in error case */
1201                 for (i = 0; i < depth; i++) {
1202                         if (!ablocks[i])
1203                                 continue;
1204                         ext4_free_blocks(handle, inode, NULL, ablocks[i], 1,
1205                                          EXT4_FREE_BLOCKS_METADATA);
1206                 }
1207         }
1208         kfree(ablocks);
1209
1210         return err;
1211 }
1212
1213 /*
1214  * ext4_ext_grow_indepth:
1215  * implements tree growing procedure:
1216  * - allocates new block
1217  * - moves top-level data (index block or leaf) into the new block
1218  * - initializes new top-level, creating index that points to the
1219  *   just created block
1220  */
1221 static int ext4_ext_grow_indepth(handle_t *handle, struct inode *inode,
1222                                  unsigned int flags,
1223                                  struct ext4_extent *newext)
1224 {
1225         struct ext4_extent_header *neh;
1226         struct buffer_head *bh;
1227         ext4_fsblk_t newblock;
1228         int err = 0;
1229
1230         newblock = ext4_ext_new_meta_block(handle, inode, NULL,
1231                 newext, &err, flags);
1232         if (newblock == 0)
1233                 return err;
1234
1235         bh = sb_getblk(inode->i_sb, newblock);
1236         if (unlikely(!bh))
1237                 return -ENOMEM;
1238         lock_buffer(bh);
1239
1240         err = ext4_journal_get_create_access(handle, bh);
1241         if (err) {
1242                 unlock_buffer(bh);
1243                 goto out;
1244         }
1245
1246         /* move top-level index/leaf into new block */
1247         memmove(bh->b_data, EXT4_I(inode)->i_data,
1248                 sizeof(EXT4_I(inode)->i_data));
1249
1250         /* set size of new block */
1251         neh = ext_block_hdr(bh);
1252         /* old root could have indexes or leaves
1253          * so calculate e_max right way */
1254         if (ext_depth(inode))
1255                 neh->eh_max = cpu_to_le16(ext4_ext_space_block_idx(inode, 0));
1256         else
1257                 neh->eh_max = cpu_to_le16(ext4_ext_space_block(inode, 0));
1258         neh->eh_magic = EXT4_EXT_MAGIC;
1259         ext4_extent_block_csum_set(inode, neh);
1260         set_buffer_uptodate(bh);
1261         unlock_buffer(bh);
1262
1263         err = ext4_handle_dirty_metadata(handle, inode, bh);
1264         if (err)
1265                 goto out;
1266
1267         /* Update top-level index: num,max,pointer */
1268         neh = ext_inode_hdr(inode);
1269         neh->eh_entries = cpu_to_le16(1);
1270         ext4_idx_store_pblock(EXT_FIRST_INDEX(neh), newblock);
1271         if (neh->eh_depth == 0) {
1272                 /* Root extent block becomes index block */
1273                 neh->eh_max = cpu_to_le16(ext4_ext_space_root_idx(inode, 0));
1274                 EXT_FIRST_INDEX(neh)->ei_block =
1275                         EXT_FIRST_EXTENT(neh)->ee_block;
1276         }
1277         ext_debug("new root: num %d(%d), lblock %d, ptr %llu\n",
1278                   le16_to_cpu(neh->eh_entries), le16_to_cpu(neh->eh_max),
1279                   le32_to_cpu(EXT_FIRST_INDEX(neh)->ei_block),
1280                   ext4_idx_pblock(EXT_FIRST_INDEX(neh)));
1281
1282         le16_add_cpu(&neh->eh_depth, 1);
1283         ext4_mark_inode_dirty(handle, inode);
1284 out:
1285         brelse(bh);
1286
1287         return err;
1288 }
1289
1290 /*
1291  * ext4_ext_create_new_leaf:
1292  * finds empty index and adds new leaf.
1293  * if no free index is found, then it requests in-depth growing.
1294  */
1295 static int ext4_ext_create_new_leaf(handle_t *handle, struct inode *inode,
1296                                     unsigned int mb_flags,
1297                                     unsigned int gb_flags,
1298                                     struct ext4_ext_path *path,
1299                                     struct ext4_extent *newext)
1300 {
1301         struct ext4_ext_path *curp;
1302         int depth, i, err = 0;
1303
1304 repeat:
1305         i = depth = ext_depth(inode);
1306
1307         /* walk up to the tree and look for free index entry */
1308         curp = path + depth;
1309         while (i > 0 && !EXT_HAS_FREE_INDEX(curp)) {
1310                 i--;
1311                 curp--;
1312         }
1313
1314         /* we use already allocated block for index block,
1315          * so subsequent data blocks should be contiguous */
1316         if (EXT_HAS_FREE_INDEX(curp)) {
1317                 /* if we found index with free entry, then use that
1318                  * entry: create all needed subtree and add new leaf */
1319                 err = ext4_ext_split(handle, inode, mb_flags, path, newext, i);
1320                 if (err)
1321                         goto out;
1322
1323                 /* refill path */
1324                 ext4_ext_drop_refs(path);
1325                 path = ext4_ext_find_extent(inode,
1326                                     (ext4_lblk_t)le32_to_cpu(newext->ee_block),
1327                                     path, gb_flags);
1328                 if (IS_ERR(path))
1329                         err = PTR_ERR(path);
1330         } else {
1331                 /* tree is full, time to grow in depth */
1332                 err = ext4_ext_grow_indepth(handle, inode, mb_flags, newext);
1333                 if (err)
1334                         goto out;
1335
1336                 /* refill path */
1337                 ext4_ext_drop_refs(path);
1338                 path = ext4_ext_find_extent(inode,
1339                                    (ext4_lblk_t)le32_to_cpu(newext->ee_block),
1340                                     path, gb_flags);
1341                 if (IS_ERR(path)) {
1342                         err = PTR_ERR(path);
1343                         goto out;
1344                 }
1345
1346                 /*
1347                  * only first (depth 0 -> 1) produces free space;
1348                  * in all other cases we have to split the grown tree
1349                  */
1350                 depth = ext_depth(inode);
1351                 if (path[depth].p_hdr->eh_entries == path[depth].p_hdr->eh_max) {
1352                         /* now we need to split */
1353                         goto repeat;
1354                 }
1355         }
1356
1357 out:
1358         return err;
1359 }
1360
1361 /*
1362  * search the closest allocated block to the left for *logical
1363  * and returns it at @logical + it's physical address at @phys
1364  * if *logical is the smallest allocated block, the function
1365  * returns 0 at @phys
1366  * return value contains 0 (success) or error code
1367  */
1368 static int ext4_ext_search_left(struct inode *inode,
1369                                 struct ext4_ext_path *path,
1370                                 ext4_lblk_t *logical, ext4_fsblk_t *phys)
1371 {
1372         struct ext4_extent_idx *ix;
1373         struct ext4_extent *ex;
1374         int depth, ee_len;
1375
1376         if (unlikely(path == NULL)) {
1377                 EXT4_ERROR_INODE(inode, "path == NULL *logical %d!", *logical);
1378                 return -EIO;
1379         }
1380         depth = path->p_depth;
1381         *phys = 0;
1382
1383         if (depth == 0 && path->p_ext == NULL)
1384                 return 0;
1385
1386         /* usually extent in the path covers blocks smaller
1387          * then *logical, but it can be that extent is the
1388          * first one in the file */
1389
1390         ex = path[depth].p_ext;
1391         ee_len = ext4_ext_get_actual_len(ex);
1392         if (*logical < le32_to_cpu(ex->ee_block)) {
1393                 if (unlikely(EXT_FIRST_EXTENT(path[depth].p_hdr) != ex)) {
1394                         EXT4_ERROR_INODE(inode,
1395                                          "EXT_FIRST_EXTENT != ex *logical %d ee_block %d!",
1396                                          *logical, le32_to_cpu(ex->ee_block));
1397                         return -EIO;
1398                 }
1399                 while (--depth >= 0) {
1400                         ix = path[depth].p_idx;
1401                         if (unlikely(ix != EXT_FIRST_INDEX(path[depth].p_hdr))) {
1402                                 EXT4_ERROR_INODE(inode,
1403                                   "ix (%d) != EXT_FIRST_INDEX (%d) (depth %d)!",
1404                                   ix != NULL ? le32_to_cpu(ix->ei_block) : 0,
1405                                   EXT_FIRST_INDEX(path[depth].p_hdr) != NULL ?
1406                 le32_to_cpu(EXT_FIRST_INDEX(path[depth].p_hdr)->ei_block) : 0,
1407                                   depth);
1408                                 return -EIO;
1409                         }
1410                 }
1411                 return 0;
1412         }
1413
1414         if (unlikely(*logical < (le32_to_cpu(ex->ee_block) + ee_len))) {
1415                 EXT4_ERROR_INODE(inode,
1416                                  "logical %d < ee_block %d + ee_len %d!",
1417                                  *logical, le32_to_cpu(ex->ee_block), ee_len);
1418                 return -EIO;
1419         }
1420
1421         *logical = le32_to_cpu(ex->ee_block) + ee_len - 1;
1422         *phys = ext4_ext_pblock(ex) + ee_len - 1;
1423         return 0;
1424 }
1425
1426 /*
1427  * search the closest allocated block to the right for *logical
1428  * and returns it at @logical + it's physical address at @phys
1429  * if *logical is the largest allocated block, the function
1430  * returns 0 at @phys
1431  * return value contains 0 (success) or error code
1432  */
1433 static int ext4_ext_search_right(struct inode *inode,
1434                                  struct ext4_ext_path *path,
1435                                  ext4_lblk_t *logical, ext4_fsblk_t *phys,
1436                                  struct ext4_extent **ret_ex)
1437 {
1438         struct buffer_head *bh = NULL;
1439         struct ext4_extent_header *eh;
1440         struct ext4_extent_idx *ix;
1441         struct ext4_extent *ex;
1442         ext4_fsblk_t block;
1443         int depth;      /* Note, NOT eh_depth; depth from top of tree */
1444         int ee_len;
1445
1446         if (unlikely(path == NULL)) {
1447                 EXT4_ERROR_INODE(inode, "path == NULL *logical %d!", *logical);
1448                 return -EIO;
1449         }
1450         depth = path->p_depth;
1451         *phys = 0;
1452
1453         if (depth == 0 && path->p_ext == NULL)
1454                 return 0;
1455
1456         /* usually extent in the path covers blocks smaller
1457          * then *logical, but it can be that extent is the
1458          * first one in the file */
1459
1460         ex = path[depth].p_ext;
1461         ee_len = ext4_ext_get_actual_len(ex);
1462         if (*logical < le32_to_cpu(ex->ee_block)) {
1463                 if (unlikely(EXT_FIRST_EXTENT(path[depth].p_hdr) != ex)) {
1464                         EXT4_ERROR_INODE(inode,
1465                                          "first_extent(path[%d].p_hdr) != ex",
1466                                          depth);
1467                         return -EIO;
1468                 }
1469                 while (--depth >= 0) {
1470                         ix = path[depth].p_idx;
1471                         if (unlikely(ix != EXT_FIRST_INDEX(path[depth].p_hdr))) {
1472                                 EXT4_ERROR_INODE(inode,
1473                                                  "ix != EXT_FIRST_INDEX *logical %d!",
1474                                                  *logical);
1475                                 return -EIO;
1476                         }
1477                 }
1478                 goto found_extent;
1479         }
1480
1481         if (unlikely(*logical < (le32_to_cpu(ex->ee_block) + ee_len))) {
1482                 EXT4_ERROR_INODE(inode,
1483                                  "logical %d < ee_block %d + ee_len %d!",
1484                                  *logical, le32_to_cpu(ex->ee_block), ee_len);
1485                 return -EIO;
1486         }
1487
1488         if (ex != EXT_LAST_EXTENT(path[depth].p_hdr)) {
1489                 /* next allocated block in this leaf */
1490                 ex++;
1491                 goto found_extent;
1492         }
1493
1494         /* go up and search for index to the right */
1495         while (--depth >= 0) {
1496                 ix = path[depth].p_idx;
1497                 if (ix != EXT_LAST_INDEX(path[depth].p_hdr))
1498                         goto got_index;
1499         }
1500
1501         /* we've gone up to the root and found no index to the right */
1502         return 0;
1503
1504 got_index:
1505         /* we've found index to the right, let's
1506          * follow it and find the closest allocated
1507          * block to the right */
1508         ix++;
1509         block = ext4_idx_pblock(ix);
1510         while (++depth < path->p_depth) {
1511                 /* subtract from p_depth to get proper eh_depth */
1512                 bh = read_extent_tree_block(inode, block,
1513                                             path->p_depth - depth, 0);
1514                 if (IS_ERR(bh))
1515                         return PTR_ERR(bh);
1516                 eh = ext_block_hdr(bh);
1517                 ix = EXT_FIRST_INDEX(eh);
1518                 block = ext4_idx_pblock(ix);
1519                 put_bh(bh);
1520         }
1521
1522         bh = read_extent_tree_block(inode, block, path->p_depth - depth, 0);
1523         if (IS_ERR(bh))
1524                 return PTR_ERR(bh);
1525         eh = ext_block_hdr(bh);
1526         ex = EXT_FIRST_EXTENT(eh);
1527 found_extent:
1528         *logical = le32_to_cpu(ex->ee_block);
1529         *phys = ext4_ext_pblock(ex);
1530         *ret_ex = ex;
1531         if (bh)
1532                 put_bh(bh);
1533         return 0;
1534 }
1535
1536 /*
1537  * ext4_ext_next_allocated_block:
1538  * returns allocated block in subsequent extent or EXT_MAX_BLOCKS.
1539  * NOTE: it considers block number from index entry as
1540  * allocated block. Thus, index entries have to be consistent
1541  * with leaves.
1542  */
1543 static ext4_lblk_t
1544 ext4_ext_next_allocated_block(struct ext4_ext_path *path)
1545 {
1546         int depth;
1547
1548         BUG_ON(path == NULL);
1549         depth = path->p_depth;
1550
1551         if (depth == 0 && path->p_ext == NULL)
1552                 return EXT_MAX_BLOCKS;
1553
1554         while (depth >= 0) {
1555                 if (depth == path->p_depth) {
1556                         /* leaf */
1557                         if (path[depth].p_ext &&
1558                                 path[depth].p_ext !=
1559                                         EXT_LAST_EXTENT(path[depth].p_hdr))
1560                           return le32_to_cpu(path[depth].p_ext[1].ee_block);
1561                 } else {
1562                         /* index */
1563                         if (path[depth].p_idx !=
1564                                         EXT_LAST_INDEX(path[depth].p_hdr))
1565                           return le32_to_cpu(path[depth].p_idx[1].ei_block);
1566                 }
1567                 depth--;
1568         }
1569
1570         return EXT_MAX_BLOCKS;
1571 }
1572
1573 /*
1574  * ext4_ext_next_leaf_block:
1575  * returns first allocated block from next leaf or EXT_MAX_BLOCKS
1576  */
1577 static ext4_lblk_t ext4_ext_next_leaf_block(struct ext4_ext_path *path)
1578 {
1579         int depth;
1580
1581         BUG_ON(path == NULL);
1582         depth = path->p_depth;
1583
1584         /* zero-tree has no leaf blocks at all */
1585         if (depth == 0)
1586                 return EXT_MAX_BLOCKS;
1587
1588         /* go to index block */
1589         depth--;
1590
1591         while (depth >= 0) {
1592                 if (path[depth].p_idx !=
1593                                 EXT_LAST_INDEX(path[depth].p_hdr))
1594                         return (ext4_lblk_t)
1595                                 le32_to_cpu(path[depth].p_idx[1].ei_block);
1596                 depth--;
1597         }
1598
1599         return EXT_MAX_BLOCKS;
1600 }
1601
1602 /*
1603  * ext4_ext_correct_indexes:
1604  * if leaf gets modified and modified extent is first in the leaf,
1605  * then we have to correct all indexes above.
1606  * TODO: do we need to correct tree in all cases?
1607  */
1608 static int ext4_ext_correct_indexes(handle_t *handle, struct inode *inode,
1609                                 struct ext4_ext_path *path)
1610 {
1611         struct ext4_extent_header *eh;
1612         int depth = ext_depth(inode);
1613         struct ext4_extent *ex;
1614         __le32 border;
1615         int k, err = 0;
1616
1617         eh = path[depth].p_hdr;
1618         ex = path[depth].p_ext;
1619
1620         if (unlikely(ex == NULL || eh == NULL)) {
1621                 EXT4_ERROR_INODE(inode,
1622                                  "ex %p == NULL or eh %p == NULL", ex, eh);
1623                 return -EIO;
1624         }
1625
1626         if (depth == 0) {
1627                 /* there is no tree at all */
1628                 return 0;
1629         }
1630
1631         if (ex != EXT_FIRST_EXTENT(eh)) {
1632                 /* we correct tree if first leaf got modified only */
1633                 return 0;
1634         }
1635
1636         /*
1637          * TODO: we need correction if border is smaller than current one
1638          */
1639         k = depth - 1;
1640         border = path[depth].p_ext->ee_block;
1641         err = ext4_ext_get_access(handle, inode, path + k);
1642         if (err)
1643                 return err;
1644         path[k].p_idx->ei_block = border;
1645         err = ext4_ext_dirty(handle, inode, path + k);
1646         if (err)
1647                 return err;
1648
1649         while (k--) {
1650                 /* change all left-side indexes */
1651                 if (path[k+1].p_idx != EXT_FIRST_INDEX(path[k+1].p_hdr))
1652                         break;
1653                 err = ext4_ext_get_access(handle, inode, path + k);
1654                 if (err)
1655                         break;
1656                 path[k].p_idx->ei_block = border;
1657                 err = ext4_ext_dirty(handle, inode, path + k);
1658                 if (err)
1659                         break;
1660         }
1661
1662         return err;
1663 }
1664
1665 int
1666 ext4_can_extents_be_merged(struct inode *inode, struct ext4_extent *ex1,
1667                                 struct ext4_extent *ex2)
1668 {
1669         unsigned short ext1_ee_len, ext2_ee_len;
1670
1671         /*
1672          * Make sure that both extents are initialized. We don't merge
1673          * uninitialized extents so that we can be sure that end_io code has
1674          * the extent that was written properly split out and conversion to
1675          * initialized is trivial.
1676          */
1677         if (ext4_ext_is_uninitialized(ex1) || ext4_ext_is_uninitialized(ex2))
1678                 return 0;
1679
1680         ext1_ee_len = ext4_ext_get_actual_len(ex1);
1681         ext2_ee_len = ext4_ext_get_actual_len(ex2);
1682
1683         if (le32_to_cpu(ex1->ee_block) + ext1_ee_len !=
1684                         le32_to_cpu(ex2->ee_block))
1685                 return 0;
1686
1687         /*
1688          * To allow future support for preallocated extents to be added
1689          * as an RO_COMPAT feature, refuse to merge to extents if
1690          * this can result in the top bit of ee_len being set.
1691          */
1692         if (ext1_ee_len + ext2_ee_len > EXT_INIT_MAX_LEN)
1693                 return 0;
1694 #ifdef AGGRESSIVE_TEST
1695         if (ext1_ee_len >= 4)
1696                 return 0;
1697 #endif
1698
1699         if (ext4_ext_pblock(ex1) + ext1_ee_len == ext4_ext_pblock(ex2))
1700                 return 1;
1701         return 0;
1702 }
1703
1704 /*
1705  * This function tries to merge the "ex" extent to the next extent in the tree.
1706  * It always tries to merge towards right. If you want to merge towards
1707  * left, pass "ex - 1" as argument instead of "ex".
1708  * Returns 0 if the extents (ex and ex+1) were _not_ merged and returns
1709  * 1 if they got merged.
1710  */
1711 static int ext4_ext_try_to_merge_right(struct inode *inode,
1712                                  struct ext4_ext_path *path,
1713                                  struct ext4_extent *ex)
1714 {
1715         struct ext4_extent_header *eh;
1716         unsigned int depth, len;
1717         int merge_done = 0;
1718         int uninitialized = 0;
1719
1720         depth = ext_depth(inode);
1721         BUG_ON(path[depth].p_hdr == NULL);
1722         eh = path[depth].p_hdr;
1723
1724         while (ex < EXT_LAST_EXTENT(eh)) {
1725                 if (!ext4_can_extents_be_merged(inode, ex, ex + 1))
1726                         break;
1727                 /* merge with next extent! */
1728                 if (ext4_ext_is_uninitialized(ex))
1729                         uninitialized = 1;
1730                 ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex)
1731                                 + ext4_ext_get_actual_len(ex + 1));
1732                 if (uninitialized)
1733                         ext4_ext_mark_uninitialized(ex);
1734
1735                 if (ex + 1 < EXT_LAST_EXTENT(eh)) {
1736                         len = (EXT_LAST_EXTENT(eh) - ex - 1)
1737                                 * sizeof(struct ext4_extent);
1738                         memmove(ex + 1, ex + 2, len);
1739                 }
1740                 le16_add_cpu(&eh->eh_entries, -1);
1741                 merge_done = 1;
1742                 WARN_ON(eh->eh_entries == 0);
1743                 if (!eh->eh_entries)
1744                         EXT4_ERROR_INODE(inode, "eh->eh_entries = 0!");
1745         }
1746
1747         return merge_done;
1748 }
1749
1750 /*
1751  * This function does a very simple check to see if we can collapse
1752  * an extent tree with a single extent tree leaf block into the inode.
1753  */
1754 static void ext4_ext_try_to_merge_up(handle_t *handle,
1755                                      struct inode *inode,
1756                                      struct ext4_ext_path *path)
1757 {
1758         size_t s;
1759         unsigned max_root = ext4_ext_space_root(inode, 0);
1760         ext4_fsblk_t blk;
1761
1762         if ((path[0].p_depth != 1) ||
1763             (le16_to_cpu(path[0].p_hdr->eh_entries) != 1) ||
1764             (le16_to_cpu(path[1].p_hdr->eh_entries) > max_root))
1765                 return;
1766
1767         /*
1768          * We need to modify the block allocation bitmap and the block
1769          * group descriptor to release the extent tree block.  If we
1770          * can't get the journal credits, give up.
1771          */
1772         if (ext4_journal_extend(handle, 2))
1773                 return;
1774
1775         /*
1776          * Copy the extent data up to the inode
1777          */
1778         blk = ext4_idx_pblock(path[0].p_idx);
1779         s = le16_to_cpu(path[1].p_hdr->eh_entries) *
1780                 sizeof(struct ext4_extent_idx);
1781         s += sizeof(struct ext4_extent_header);
1782
1783         memcpy(path[0].p_hdr, path[1].p_hdr, s);
1784         path[0].p_depth = 0;
1785         path[0].p_ext = EXT_FIRST_EXTENT(path[0].p_hdr) +
1786                 (path[1].p_ext - EXT_FIRST_EXTENT(path[1].p_hdr));
1787         path[0].p_hdr->eh_max = cpu_to_le16(max_root);
1788
1789         brelse(path[1].p_bh);
1790         ext4_free_blocks(handle, inode, NULL, blk, 1,
1791                          EXT4_FREE_BLOCKS_METADATA | EXT4_FREE_BLOCKS_FORGET |
1792                          EXT4_FREE_BLOCKS_RESERVE);
1793 }
1794
1795 /*
1796  * This function tries to merge the @ex extent to neighbours in the tree.
1797  * return 1 if merge left else 0.
1798  */
1799 static void ext4_ext_try_to_merge(handle_t *handle,
1800                                   struct inode *inode,
1801                                   struct ext4_ext_path *path,
1802                                   struct ext4_extent *ex) {
1803         struct ext4_extent_header *eh;
1804         unsigned int depth;
1805         int merge_done = 0;
1806
1807         depth = ext_depth(inode);
1808         BUG_ON(path[depth].p_hdr == NULL);
1809         eh = path[depth].p_hdr;
1810
1811         if (ex > EXT_FIRST_EXTENT(eh))
1812                 merge_done = ext4_ext_try_to_merge_right(inode, path, ex - 1);
1813
1814         if (!merge_done)
1815                 (void) ext4_ext_try_to_merge_right(inode, path, ex);
1816
1817         ext4_ext_try_to_merge_up(handle, inode, path);
1818 }
1819
1820 /*
1821  * check if a portion of the "newext" extent overlaps with an
1822  * existing extent.
1823  *
1824  * If there is an overlap discovered, it updates the length of the newext
1825  * such that there will be no overlap, and then returns 1.
1826  * If there is no overlap found, it returns 0.
1827  */
1828 static unsigned int ext4_ext_check_overlap(struct ext4_sb_info *sbi,
1829                                            struct inode *inode,
1830                                            struct ext4_extent *newext,
1831                                            struct ext4_ext_path *path)
1832 {
1833         ext4_lblk_t b1, b2;
1834         unsigned int depth, len1;
1835         unsigned int ret = 0;
1836
1837         b1 = le32_to_cpu(newext->ee_block);
1838         len1 = ext4_ext_get_actual_len(newext);
1839         depth = ext_depth(inode);
1840         if (!path[depth].p_ext)
1841                 goto out;
1842         b2 = le32_to_cpu(path[depth].p_ext->ee_block);
1843         b2 &= ~(sbi->s_cluster_ratio - 1);
1844
1845         /*
1846          * get the next allocated block if the extent in the path
1847          * is before the requested block(s)
1848          */
1849         if (b2 < b1) {
1850                 b2 = ext4_ext_next_allocated_block(path);
1851                 if (b2 == EXT_MAX_BLOCKS)
1852                         goto out;
1853                 b2 &= ~(sbi->s_cluster_ratio - 1);
1854         }
1855
1856         /* check for wrap through zero on extent logical start block*/
1857         if (b1 + len1 < b1) {
1858                 len1 = EXT_MAX_BLOCKS - b1;
1859                 newext->ee_len = cpu_to_le16(len1);
1860                 ret = 1;
1861         }
1862
1863         /* check for overlap */
1864         if (b1 + len1 > b2) {
1865                 newext->ee_len = cpu_to_le16(b2 - b1);
1866                 ret = 1;
1867         }
1868 out:
1869         return ret;
1870 }
1871
1872 /*
1873  * ext4_ext_insert_extent:
1874  * tries to merge requsted extent into the existing extent or
1875  * inserts requested extent as new one into the tree,
1876  * creating new leaf in the no-space case.
1877  */
1878 int ext4_ext_insert_extent(handle_t *handle, struct inode *inode,
1879                                 struct ext4_ext_path *path,
1880                                 struct ext4_extent *newext, int gb_flags)
1881 {
1882         struct ext4_extent_header *eh;
1883         struct ext4_extent *ex, *fex;
1884         struct ext4_extent *nearex; /* nearest extent */
1885         struct ext4_ext_path *npath = NULL;
1886         int depth, len, err;
1887         ext4_lblk_t next;
1888         unsigned uninitialized = 0;
1889         int mb_flags = 0;
1890
1891         if (unlikely(ext4_ext_get_actual_len(newext) == 0)) {
1892                 EXT4_ERROR_INODE(inode, "ext4_ext_get_actual_len(newext) == 0");
1893                 return -EIO;
1894         }
1895         depth = ext_depth(inode);
1896         ex = path[depth].p_ext;
1897         eh = path[depth].p_hdr;
1898         if (unlikely(path[depth].p_hdr == NULL)) {
1899                 EXT4_ERROR_INODE(inode, "path[%d].p_hdr == NULL", depth);
1900                 return -EIO;
1901         }
1902
1903         /* try to insert block into found extent and return */
1904         if (ex && !(gb_flags & EXT4_GET_BLOCKS_PRE_IO)) {
1905
1906                 /*
1907                  * Try to see whether we should rather test the extent on
1908                  * right from ex, or from the left of ex. This is because
1909                  * ext4_ext_find_extent() can return either extent on the
1910                  * left, or on the right from the searched position. This
1911                  * will make merging more effective.
1912                  */
1913                 if (ex < EXT_LAST_EXTENT(eh) &&
1914                     (le32_to_cpu(ex->ee_block) +
1915                     ext4_ext_get_actual_len(ex) <
1916                     le32_to_cpu(newext->ee_block))) {
1917                         ex += 1;
1918                         goto prepend;
1919                 } else if ((ex > EXT_FIRST_EXTENT(eh)) &&
1920                            (le32_to_cpu(newext->ee_block) +
1921                            ext4_ext_get_actual_len(newext) <
1922                            le32_to_cpu(ex->ee_block)))
1923                         ex -= 1;
1924
1925                 /* Try to append newex to the ex */
1926                 if (ext4_can_extents_be_merged(inode, ex, newext)) {
1927                         ext_debug("append [%d]%d block to %u:[%d]%d"
1928                                   "(from %llu)\n",
1929                                   ext4_ext_is_uninitialized(newext),
1930                                   ext4_ext_get_actual_len(newext),
1931                                   le32_to_cpu(ex->ee_block),
1932                                   ext4_ext_is_uninitialized(ex),
1933                                   ext4_ext_get_actual_len(ex),
1934                                   ext4_ext_pblock(ex));
1935                         err = ext4_ext_get_access(handle, inode,
1936                                                   path + depth);
1937                         if (err)
1938                                 return err;
1939
1940                         /*
1941                          * ext4_can_extents_be_merged should have checked
1942                          * that either both extents are uninitialized, or
1943                          * both aren't. Thus we need to check only one of
1944                          * them here.
1945                          */
1946                         if (ext4_ext_is_uninitialized(ex))
1947                                 uninitialized = 1;
1948                         ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex)
1949                                         + ext4_ext_get_actual_len(newext));
1950                         if (uninitialized)
1951                                 ext4_ext_mark_uninitialized(ex);
1952                         eh = path[depth].p_hdr;
1953                         nearex = ex;
1954                         goto merge;
1955                 }
1956
1957 prepend:
1958                 /* Try to prepend newex to the ex */
1959                 if (ext4_can_extents_be_merged(inode, newext, ex)) {
1960                         ext_debug("prepend %u[%d]%d block to %u:[%d]%d"
1961                                   "(from %llu)\n",
1962                                   le32_to_cpu(newext->ee_block),
1963                                   ext4_ext_is_uninitialized(newext),
1964                                   ext4_ext_get_actual_len(newext),
1965                                   le32_to_cpu(ex->ee_block),
1966                                   ext4_ext_is_uninitialized(ex),
1967                                   ext4_ext_get_actual_len(ex),
1968                                   ext4_ext_pblock(ex));
1969                         err = ext4_ext_get_access(handle, inode,
1970                                                   path + depth);
1971                         if (err)
1972                                 return err;
1973
1974                         /*
1975                          * ext4_can_extents_be_merged should have checked
1976                          * that either both extents are uninitialized, or
1977                          * both aren't. Thus we need to check only one of
1978                          * them here.
1979                          */
1980                         if (ext4_ext_is_uninitialized(ex))
1981                                 uninitialized = 1;
1982                         ex->ee_block = newext->ee_block;
1983                         ext4_ext_store_pblock(ex, ext4_ext_pblock(newext));
1984                         ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex)
1985                                         + ext4_ext_get_actual_len(newext));
1986                         if (uninitialized)
1987                                 ext4_ext_mark_uninitialized(ex);
1988                         eh = path[depth].p_hdr;
1989                         nearex = ex;
1990                         goto merge;
1991                 }
1992         }
1993
1994         depth = ext_depth(inode);
1995         eh = path[depth].p_hdr;
1996         if (le16_to_cpu(eh->eh_entries) < le16_to_cpu(eh->eh_max))
1997                 goto has_space;
1998
1999         /* probably next leaf has space for us? */
2000         fex = EXT_LAST_EXTENT(eh);
2001         next = EXT_MAX_BLOCKS;
2002         if (le32_to_cpu(newext->ee_block) > le32_to_cpu(fex->ee_block))
2003                 next = ext4_ext_next_leaf_block(path);
2004         if (next != EXT_MAX_BLOCKS) {
2005                 ext_debug("next leaf block - %u\n", next);
2006                 BUG_ON(npath != NULL);
2007                 npath = ext4_ext_find_extent(inode, next, NULL, 0);
2008                 if (IS_ERR(npath))
2009                         return PTR_ERR(npath);
2010                 BUG_ON(npath->p_depth != path->p_depth);
2011                 eh = npath[depth].p_hdr;
2012                 if (le16_to_cpu(eh->eh_entries) < le16_to_cpu(eh->eh_max)) {
2013                         ext_debug("next leaf isn't full(%d)\n",
2014                                   le16_to_cpu(eh->eh_entries));
2015                         path = npath;
2016                         goto has_space;
2017                 }
2018                 ext_debug("next leaf has no free space(%d,%d)\n",
2019                           le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max));
2020         }
2021
2022         /*
2023          * There is no free space in the found leaf.
2024          * We're gonna add a new leaf in the tree.
2025          */
2026         if (gb_flags & EXT4_GET_BLOCKS_METADATA_NOFAIL)
2027                 mb_flags = EXT4_MB_USE_RESERVED;
2028         err = ext4_ext_create_new_leaf(handle, inode, mb_flags, gb_flags,
2029                                        path, newext);
2030         if (err)
2031                 goto cleanup;
2032         depth = ext_depth(inode);
2033         eh = path[depth].p_hdr;
2034
2035 has_space:
2036         nearex = path[depth].p_ext;
2037
2038         err = ext4_ext_get_access(handle, inode, path + depth);
2039         if (err)
2040                 goto cleanup;
2041
2042         if (!nearex) {
2043                 /* there is no extent in this leaf, create first one */
2044                 ext_debug("first extent in the leaf: %u:%llu:[%d]%d\n",
2045                                 le32_to_cpu(newext->ee_block),
2046                                 ext4_ext_pblock(newext),
2047                                 ext4_ext_is_uninitialized(newext),
2048                                 ext4_ext_get_actual_len(newext));
2049                 nearex = EXT_FIRST_EXTENT(eh);
2050         } else {
2051                 if (le32_to_cpu(newext->ee_block)
2052                            > le32_to_cpu(nearex->ee_block)) {
2053                         /* Insert after */
2054                         ext_debug("insert %u:%llu:[%d]%d before: "
2055                                         "nearest %p\n",
2056                                         le32_to_cpu(newext->ee_block),
2057                                         ext4_ext_pblock(newext),
2058                                         ext4_ext_is_uninitialized(newext),
2059                                         ext4_ext_get_actual_len(newext),
2060                                         nearex);
2061                         nearex++;
2062                 } else {
2063                         /* Insert before */
2064                         BUG_ON(newext->ee_block == nearex->ee_block);
2065                         ext_debug("insert %u:%llu:[%d]%d after: "
2066                                         "nearest %p\n",
2067                                         le32_to_cpu(newext->ee_block),
2068                                         ext4_ext_pblock(newext),
2069                                         ext4_ext_is_uninitialized(newext),
2070                                         ext4_ext_get_actual_len(newext),
2071                                         nearex);
2072                 }
2073                 len = EXT_LAST_EXTENT(eh) - nearex + 1;
2074                 if (len > 0) {
2075                         ext_debug("insert %u:%llu:[%d]%d: "
2076                                         "move %d extents from 0x%p to 0x%p\n",
2077                                         le32_to_cpu(newext->ee_block),
2078                                         ext4_ext_pblock(newext),
2079                                         ext4_ext_is_uninitialized(newext),
2080                                         ext4_ext_get_actual_len(newext),
2081                                         len, nearex, nearex + 1);
2082                         memmove(nearex + 1, nearex,
2083                                 len * sizeof(struct ext4_extent));
2084                 }
2085         }
2086
2087         le16_add_cpu(&eh->eh_entries, 1);
2088         path[depth].p_ext = nearex;
2089         nearex->ee_block = newext->ee_block;
2090         ext4_ext_store_pblock(nearex, ext4_ext_pblock(newext));
2091         nearex->ee_len = newext->ee_len;
2092
2093 merge:
2094         /* try to merge extents */
2095         if (!(gb_flags & EXT4_GET_BLOCKS_PRE_IO))
2096                 ext4_ext_try_to_merge(handle, inode, path, nearex);
2097
2098
2099         /* time to correct all indexes above */
2100         err = ext4_ext_correct_indexes(handle, inode, path);
2101         if (err)
2102                 goto cleanup;
2103
2104         err = ext4_ext_dirty(handle, inode, path + path->p_depth);
2105
2106 cleanup:
2107         if (npath) {
2108                 ext4_ext_drop_refs(npath);
2109                 kfree(npath);
2110         }
2111         return err;
2112 }
2113
2114 static int ext4_fill_fiemap_extents(struct inode *inode,
2115                                     ext4_lblk_t block, ext4_lblk_t num,
2116                                     struct fiemap_extent_info *fieinfo)
2117 {
2118         struct ext4_ext_path *path = NULL;
2119         struct ext4_extent *ex;
2120         struct extent_status es;
2121         ext4_lblk_t next, next_del, start = 0, end = 0;
2122         ext4_lblk_t last = block + num;
2123         int exists, depth = 0, err = 0;
2124         unsigned int flags = 0;
2125         unsigned char blksize_bits = inode->i_sb->s_blocksize_bits;
2126
2127         while (block < last && block != EXT_MAX_BLOCKS) {
2128                 num = last - block;
2129                 /* find extent for this block */
2130                 down_read(&EXT4_I(inode)->i_data_sem);
2131
2132                 if (path && ext_depth(inode) != depth) {
2133                         /* depth was changed. we have to realloc path */
2134                         kfree(path);
2135                         path = NULL;
2136                 }
2137
2138                 path = ext4_ext_find_extent(inode, block, path, 0);
2139                 if (IS_ERR(path)) {
2140                         up_read(&EXT4_I(inode)->i_data_sem);
2141                         err = PTR_ERR(path);
2142                         path = NULL;
2143                         break;
2144                 }
2145
2146                 depth = ext_depth(inode);
2147                 if (unlikely(path[depth].p_hdr == NULL)) {
2148                         up_read(&EXT4_I(inode)->i_data_sem);
2149                         EXT4_ERROR_INODE(inode, "path[%d].p_hdr == NULL", depth);
2150                         err = -EIO;
2151                         break;
2152                 }
2153                 ex = path[depth].p_ext;
2154                 next = ext4_ext_next_allocated_block(path);
2155                 ext4_ext_drop_refs(path);
2156
2157                 flags = 0;
2158                 exists = 0;
2159                 if (!ex) {
2160                         /* there is no extent yet, so try to allocate
2161                          * all requested space */
2162                         start = block;
2163                         end = block + num;
2164                 } else if (le32_to_cpu(ex->ee_block) > block) {
2165                         /* need to allocate space before found extent */
2166                         start = block;
2167                         end = le32_to_cpu(ex->ee_block);
2168                         if (block + num < end)
2169                                 end = block + num;
2170                 } else if (block >= le32_to_cpu(ex->ee_block)
2171                                         + ext4_ext_get_actual_len(ex)) {
2172                         /* need to allocate space after found extent */
2173                         start = block;
2174                         end = block + num;
2175                         if (end >= next)
2176                                 end = next;
2177                 } else if (block >= le32_to_cpu(ex->ee_block)) {
2178                         /*
2179                          * some part of requested space is covered
2180                          * by found extent
2181                          */
2182                         start = block;
2183                         end = le32_to_cpu(ex->ee_block)
2184                                 + ext4_ext_get_actual_len(ex);
2185                         if (block + num < end)
2186                                 end = block + num;
2187                         exists = 1;
2188                 } else {
2189                         BUG();
2190                 }
2191                 BUG_ON(end <= start);
2192
2193                 if (!exists) {
2194                         es.es_lblk = start;
2195                         es.es_len = end - start;
2196                         es.es_pblk = 0;
2197                 } else {
2198                         es.es_lblk = le32_to_cpu(ex->ee_block);
2199                         es.es_len = ext4_ext_get_actual_len(ex);
2200                         es.es_pblk = ext4_ext_pblock(ex);
2201                         if (ext4_ext_is_uninitialized(ex))
2202                                 flags |= FIEMAP_EXTENT_UNWRITTEN;
2203                 }
2204
2205                 /*
2206                  * Find delayed extent and update es accordingly. We call
2207                  * it even in !exists case to find out whether es is the
2208                  * last existing extent or not.
2209                  */
2210                 next_del = ext4_find_delayed_extent(inode, &es);
2211                 if (!exists && next_del) {
2212                         exists = 1;
2213                         flags |= (FIEMAP_EXTENT_DELALLOC |
2214                                   FIEMAP_EXTENT_UNKNOWN);
2215                 }
2216                 up_read(&EXT4_I(inode)->i_data_sem);
2217
2218                 if (unlikely(es.es_len == 0)) {
2219                         EXT4_ERROR_INODE(inode, "es.es_len == 0");
2220                         err = -EIO;
2221                         break;
2222                 }
2223
2224                 /*
2225                  * This is possible iff next == next_del == EXT_MAX_BLOCKS.
2226                  * we need to check next == EXT_MAX_BLOCKS because it is
2227                  * possible that an extent is with unwritten and delayed
2228                  * status due to when an extent is delayed allocated and
2229                  * is allocated by fallocate status tree will track both of
2230                  * them in a extent.
2231                  *
2232                  * So we could return a unwritten and delayed extent, and
2233                  * its block is equal to 'next'.
2234                  */
2235                 if (next == next_del && next == EXT_MAX_BLOCKS) {
2236                         flags |= FIEMAP_EXTENT_LAST;
2237                         if (unlikely(next_del != EXT_MAX_BLOCKS ||
2238                                      next != EXT_MAX_BLOCKS)) {
2239                                 EXT4_ERROR_INODE(inode,
2240                                                  "next extent == %u, next "
2241                                                  "delalloc extent = %u",
2242                                                  next, next_del);
2243                                 err = -EIO;
2244                                 break;
2245                         }
2246                 }
2247
2248                 if (exists) {
2249                         err = fiemap_fill_next_extent(fieinfo,
2250                                 (__u64)es.es_lblk << blksize_bits,
2251                                 (__u64)es.es_pblk << blksize_bits,
2252                                 (__u64)es.es_len << blksize_bits,
2253                                 flags);
2254                         if (err < 0)
2255                                 break;
2256                         if (err == 1) {
2257                                 err = 0;
2258                                 break;
2259                         }
2260                 }
2261
2262                 block = es.es_lblk + es.es_len;
2263         }
2264
2265         if (path) {
2266                 ext4_ext_drop_refs(path);
2267                 kfree(path);
2268         }
2269
2270         return err;
2271 }
2272
2273 /*
2274  * ext4_ext_put_gap_in_cache:
2275  * calculate boundaries of the gap that the requested block fits into
2276  * and cache this gap
2277  */
2278 static void
2279 ext4_ext_put_gap_in_cache(struct inode *inode, struct ext4_ext_path *path,
2280                                 ext4_lblk_t block)
2281 {
2282         int depth = ext_depth(inode);
2283         unsigned long len = 0;
2284         ext4_lblk_t lblock = 0;
2285         struct ext4_extent *ex;
2286
2287         ex = path[depth].p_ext;
2288         if (ex == NULL) {
2289                 /*
2290                  * there is no extent yet, so gap is [0;-] and we
2291                  * don't cache it
2292                  */
2293                 ext_debug("cache gap(whole file):");
2294         } else if (block < le32_to_cpu(ex->ee_block)) {
2295                 lblock = block;
2296                 len = le32_to_cpu(ex->ee_block) - block;
2297                 ext_debug("cache gap(before): %u [%u:%u]",
2298                                 block,
2299                                 le32_to_cpu(ex->ee_block),
2300                                  ext4_ext_get_actual_len(ex));
2301                 if (!ext4_find_delalloc_range(inode, lblock, lblock + len - 1))
2302                         ext4_es_insert_extent(inode, lblock, len, ~0,
2303                                               EXTENT_STATUS_HOLE);
2304         } else if (block >= le32_to_cpu(ex->ee_block)
2305                         + ext4_ext_get_actual_len(ex)) {
2306                 ext4_lblk_t next;
2307                 lblock = le32_to_cpu(ex->ee_block)
2308                         + ext4_ext_get_actual_len(ex);
2309
2310                 next = ext4_ext_next_allocated_block(path);
2311                 ext_debug("cache gap(after): [%u:%u] %u",
2312                                 le32_to_cpu(ex->ee_block),
2313                                 ext4_ext_get_actual_len(ex),
2314                                 block);
2315                 BUG_ON(next == lblock);
2316                 len = next - lblock;
2317                 if (!ext4_find_delalloc_range(inode, lblock, lblock + len - 1))
2318                         ext4_es_insert_extent(inode, lblock, len, ~0,
2319                                               EXTENT_STATUS_HOLE);
2320         } else {
2321                 BUG();
2322         }
2323
2324         ext_debug(" -> %u:%lu\n", lblock, len);
2325 }
2326
2327 /*
2328  * ext4_ext_rm_idx:
2329  * removes index from the index block.
2330  */
2331 static int ext4_ext_rm_idx(handle_t *handle, struct inode *inode,
2332                         struct ext4_ext_path *path, int depth)
2333 {
2334         int err;
2335         ext4_fsblk_t leaf;
2336
2337         /* free index block */
2338         depth--;
2339         path = path + depth;
2340         leaf = ext4_idx_pblock(path->p_idx);
2341         if (unlikely(path->p_hdr->eh_entries == 0)) {
2342                 EXT4_ERROR_INODE(inode, "path->p_hdr->eh_entries == 0");
2343                 return -EIO;
2344         }
2345         err = ext4_ext_get_access(handle, inode, path);
2346         if (err)
2347                 return err;
2348
2349         if (path->p_idx != EXT_LAST_INDEX(path->p_hdr)) {
2350                 int len = EXT_LAST_INDEX(path->p_hdr) - path->p_idx;
2351                 len *= sizeof(struct ext4_extent_idx);
2352                 memmove(path->p_idx, path->p_idx + 1, len);
2353         }
2354
2355         le16_add_cpu(&path->p_hdr->eh_entries, -1);
2356         err = ext4_ext_dirty(handle, inode, path);
2357         if (err)
2358                 return err;
2359         ext_debug("index is empty, remove it, free block %llu\n", leaf);
2360         trace_ext4_ext_rm_idx(inode, leaf);
2361
2362         ext4_free_blocks(handle, inode, NULL, leaf, 1,
2363                          EXT4_FREE_BLOCKS_METADATA | EXT4_FREE_BLOCKS_FORGET);
2364
2365         while (--depth >= 0) {
2366                 if (path->p_idx != EXT_FIRST_INDEX(path->p_hdr))
2367                         break;
2368                 path--;
2369                 err = ext4_ext_get_access(handle, inode, path);
2370                 if (err)
2371                         break;
2372                 path->p_idx->ei_block = (path+1)->p_idx->ei_block;
2373                 err = ext4_ext_dirty(handle, inode, path);
2374                 if (err)
2375                         break;
2376         }
2377         return err;
2378 }
2379
2380 /*
2381  * ext4_ext_calc_credits_for_single_extent:
2382  * This routine returns max. credits that needed to insert an extent
2383  * to the extent tree.
2384  * When pass the actual path, the caller should calculate credits
2385  * under i_data_sem.
2386  */
2387 int ext4_ext_calc_credits_for_single_extent(struct inode *inode, int nrblocks,
2388                                                 struct ext4_ext_path *path)
2389 {
2390         if (path) {
2391                 int depth = ext_depth(inode);
2392                 int ret = 0;
2393
2394                 /* probably there is space in leaf? */
2395                 if (le16_to_cpu(path[depth].p_hdr->eh_entries)
2396                                 < le16_to_cpu(path[depth].p_hdr->eh_max)) {
2397
2398                         /*
2399                          *  There are some space in the leaf tree, no
2400                          *  need to account for leaf block credit
2401                          *
2402                          *  bitmaps and block group descriptor blocks
2403                          *  and other metadata blocks still need to be
2404                          *  accounted.
2405                          */
2406                         /* 1 bitmap, 1 block group descriptor */
2407                         ret = 2 + EXT4_META_TRANS_BLOCKS(inode->i_sb);
2408                         return ret;
2409                 }
2410         }
2411
2412         return ext4_chunk_trans_blocks(inode, nrblocks);
2413 }
2414
2415 /*
2416  * How many index/leaf blocks need to change/allocate to add @extents extents?
2417  *
2418  * If we add a single extent, then in the worse case, each tree level
2419  * index/leaf need to be changed in case of the tree split.
2420  *
2421  * If more extents are inserted, they could cause the whole tree split more
2422  * than once, but this is really rare.
2423  */
2424 int ext4_ext_index_trans_blocks(struct inode *inode, int extents)
2425 {
2426         int index;
2427         int depth;
2428
2429         /* If we are converting the inline data, only one is needed here. */
2430         if (ext4_has_inline_data(inode))
2431                 return 1;
2432
2433         depth = ext_depth(inode);
2434
2435         if (extents <= 1)
2436                 index = depth * 2;
2437         else
2438                 index = depth * 3;
2439
2440         return index;
2441 }
2442
2443 static inline int get_default_free_blocks_flags(struct inode *inode)
2444 {
2445         if (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode))
2446                 return EXT4_FREE_BLOCKS_METADATA | EXT4_FREE_BLOCKS_FORGET;
2447         else if (ext4_should_journal_data(inode))
2448                 return EXT4_FREE_BLOCKS_FORGET;
2449         return 0;
2450 }
2451
2452 static int ext4_remove_blocks(handle_t *handle, struct inode *inode,
2453                               struct ext4_extent *ex,
2454                               long long *partial_cluster,
2455                               ext4_lblk_t from, ext4_lblk_t to)
2456 {
2457         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2458         unsigned short ee_len =  ext4_ext_get_actual_len(ex);
2459         ext4_fsblk_t pblk;
2460         int flags = get_default_free_blocks_flags(inode);
2461
2462         /*
2463          * For bigalloc file systems, we never free a partial cluster
2464          * at the beginning of the extent.  Instead, we make a note
2465          * that we tried freeing the cluster, and check to see if we
2466          * need to free it on a subsequent call to ext4_remove_blocks,
2467          * or at the end of the ext4_truncate() operation.
2468          */
2469         flags |= EXT4_FREE_BLOCKS_NOFREE_FIRST_CLUSTER;
2470
2471         trace_ext4_remove_blocks(inode, ex, from, to, *partial_cluster);
2472         /*
2473          * If we have a partial cluster, and it's different from the
2474          * cluster of the last block, we need to explicitly free the
2475          * partial cluster here.
2476          */
2477         pblk = ext4_ext_pblock(ex) + ee_len - 1;
2478         if ((*partial_cluster > 0) &&
2479             (EXT4_B2C(sbi, pblk) != *partial_cluster)) {
2480                 ext4_free_blocks(handle, inode, NULL,
2481                                  EXT4_C2B(sbi, *partial_cluster),
2482                                  sbi->s_cluster_ratio, flags);
2483                 *partial_cluster = 0;
2484         }
2485
2486 #ifdef EXTENTS_STATS
2487         {
2488                 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2489                 spin_lock(&sbi->s_ext_stats_lock);
2490                 sbi->s_ext_blocks += ee_len;
2491                 sbi->s_ext_extents++;
2492                 if (ee_len < sbi->s_ext_min)
2493                         sbi->s_ext_min = ee_len;
2494                 if (ee_len > sbi->s_ext_max)
2495                         sbi->s_ext_max = ee_len;
2496                 if (ext_depth(inode) > sbi->s_depth_max)
2497                         sbi->s_depth_max = ext_depth(inode);
2498                 spin_unlock(&sbi->s_ext_stats_lock);
2499         }
2500 #endif
2501         if (from >= le32_to_cpu(ex->ee_block)
2502             && to == le32_to_cpu(ex->ee_block) + ee_len - 1) {
2503                 /* tail removal */
2504                 ext4_lblk_t num;
2505                 unsigned int unaligned;
2506
2507                 num = le32_to_cpu(ex->ee_block) + ee_len - from;
2508                 pblk = ext4_ext_pblock(ex) + ee_len - num;
2509                 /*
2510                  * Usually we want to free partial cluster at the end of the
2511                  * extent, except for the situation when the cluster is still
2512                  * used by any other extent (partial_cluster is negative).
2513                  */
2514                 if (*partial_cluster < 0 &&
2515                     -(*partial_cluster) == EXT4_B2C(sbi, pblk + num - 1))
2516                         flags |= EXT4_FREE_BLOCKS_NOFREE_LAST_CLUSTER;
2517
2518                 ext_debug("free last %u blocks starting %llu partial %lld\n",
2519                           num, pblk, *partial_cluster);
2520                 ext4_free_blocks(handle, inode, NULL, pblk, num, flags);
2521                 /*
2522                  * If the block range to be freed didn't start at the
2523                  * beginning of a cluster, and we removed the entire
2524                  * extent and the cluster is not used by any other extent,
2525                  * save the partial cluster here, since we might need to
2526                  * delete if we determine that the truncate operation has
2527                  * removed all of the blocks in the cluster.
2528                  *
2529                  * On the other hand, if we did not manage to free the whole
2530                  * extent, we have to mark the cluster as used (store negative
2531                  * cluster number in partial_cluster).
2532                  */
2533                 unaligned = pblk & (sbi->s_cluster_ratio - 1);
2534                 if (unaligned && (ee_len == num) &&
2535                     (*partial_cluster != -((long long)EXT4_B2C(sbi, pblk))))
2536                         *partial_cluster = EXT4_B2C(sbi, pblk);
2537                 else if (unaligned)
2538                         *partial_cluster = -((long long)EXT4_B2C(sbi, pblk));
2539                 else if (*partial_cluster > 0)
2540                         *partial_cluster = 0;
2541         } else
2542                 ext4_error(sbi->s_sb, "strange request: removal(2) "
2543                            "%u-%u from %u:%u\n",
2544                            from, to, le32_to_cpu(ex->ee_block), ee_len);
2545         return 0;
2546 }
2547
2548
2549 /*
2550  * ext4_ext_rm_leaf() Removes the extents associated with the
2551  * blocks appearing between "start" and "end", and splits the extents
2552  * if "start" and "end" appear in the same extent
2553  *
2554  * @handle: The journal handle
2555  * @inode:  The files inode
2556  * @path:   The path to the leaf
2557  * @partial_cluster: The cluster which we'll have to free if all extents
2558  *                   has been released from it. It gets negative in case
2559  *                   that the cluster is still used.
2560  * @start:  The first block to remove
2561  * @end:   The last block to remove
2562  */
2563 static int
2564 ext4_ext_rm_leaf(handle_t *handle, struct inode *inode,
2565                  struct ext4_ext_path *path,
2566                  long long *partial_cluster,
2567                  ext4_lblk_t start, ext4_lblk_t end)
2568 {
2569         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2570         int err = 0, correct_index = 0;
2571         int depth = ext_depth(inode), credits;
2572         struct ext4_extent_header *eh;
2573         ext4_lblk_t a, b;
2574         unsigned num;
2575         ext4_lblk_t ex_ee_block;
2576         unsigned short ex_ee_len;
2577         unsigned uninitialized = 0;
2578         struct ext4_extent *ex;
2579         ext4_fsblk_t pblk;
2580
2581         /* the header must be checked already in ext4_ext_remove_space() */
2582         ext_debug("truncate since %u in leaf to %u\n", start, end);
2583         if (!path[depth].p_hdr)
2584                 path[depth].p_hdr = ext_block_hdr(path[depth].p_bh);
2585         eh = path[depth].p_hdr;
2586         if (unlikely(path[depth].p_hdr == NULL)) {
2587                 EXT4_ERROR_INODE(inode, "path[%d].p_hdr == NULL", depth);
2588                 return -EIO;
2589         }
2590         /* find where to start removing */
2591         ex = path[depth].p_ext;
2592         if (!ex)
2593                 ex = EXT_LAST_EXTENT(eh);
2594
2595         ex_ee_block = le32_to_cpu(ex->ee_block);
2596         ex_ee_len = ext4_ext_get_actual_len(ex);
2597
2598         trace_ext4_ext_rm_leaf(inode, start, ex, *partial_cluster);
2599
2600         while (ex >= EXT_FIRST_EXTENT(eh) &&
2601                         ex_ee_block + ex_ee_len > start) {
2602
2603                 if (ext4_ext_is_uninitialized(ex))
2604                         uninitialized = 1;
2605                 else
2606                         uninitialized = 0;
2607
2608                 ext_debug("remove ext %u:[%d]%d\n", ex_ee_block,
2609                          uninitialized, ex_ee_len);
2610                 path[depth].p_ext = ex;
2611
2612                 a = ex_ee_block > start ? ex_ee_block : start;
2613                 b = ex_ee_block+ex_ee_len - 1 < end ?
2614                         ex_ee_block+ex_ee_len - 1 : end;
2615
2616                 ext_debug("  border %u:%u\n", a, b);
2617
2618                 /* If this extent is beyond the end of the hole, skip it */
2619                 if (end < ex_ee_block) {
2620                         /*
2621                          * We're going to skip this extent and move to another,
2622                          * so if this extent is not cluster aligned we have
2623                          * to mark the current cluster as used to avoid
2624                          * accidentally freeing it later on
2625                          */
2626                         pblk = ext4_ext_pblock(ex);
2627                         if (pblk & (sbi->s_cluster_ratio - 1))
2628                                 *partial_cluster =
2629                                         -((long long)EXT4_B2C(sbi, pblk));
2630                         ex--;
2631                         ex_ee_block = le32_to_cpu(ex->ee_block);
2632                         ex_ee_len = ext4_ext_get_actual_len(ex);
2633                         continue;
2634                 } else if (b != ex_ee_block + ex_ee_len - 1) {
2635                         EXT4_ERROR_INODE(inode,
2636                                          "can not handle truncate %u:%u "
2637                                          "on extent %u:%u",
2638                                          start, end, ex_ee_block,
2639                                          ex_ee_block + ex_ee_len - 1);
2640                         err = -EIO;
2641                         goto out;
2642                 } else if (a != ex_ee_block) {
2643                         /* remove tail of the extent */
2644                         num = a - ex_ee_block;
2645                 } else {
2646                         /* remove whole extent: excellent! */
2647                         num = 0;
2648                 }
2649                 /*
2650                  * 3 for leaf, sb, and inode plus 2 (bmap and group
2651                  * descriptor) for each block group; assume two block
2652                  * groups plus ex_ee_len/blocks_per_block_group for
2653                  * the worst case
2654                  */
2655                 credits = 7 + 2*(ex_ee_len/EXT4_BLOCKS_PER_GROUP(inode->i_sb));
2656                 if (ex == EXT_FIRST_EXTENT(eh)) {
2657                         correct_index = 1;
2658                         credits += (ext_depth(inode)) + 1;
2659                 }
2660                 credits += EXT4_MAXQUOTAS_TRANS_BLOCKS(inode->i_sb);
2661
2662                 err = ext4_ext_truncate_extend_restart(handle, inode, credits);
2663                 if (err)
2664                         goto out;
2665
2666                 err = ext4_ext_get_access(handle, inode, path + depth);
2667                 if (err)
2668                         goto out;
2669
2670                 err = ext4_remove_blocks(handle, inode, ex, partial_cluster,
2671                                          a, b);
2672                 if (err)
2673                         goto out;
2674
2675                 if (num == 0)
2676                         /* this extent is removed; mark slot entirely unused */
2677                         ext4_ext_store_pblock(ex, 0);
2678
2679                 ex->ee_len = cpu_to_le16(num);
2680                 /*
2681                  * Do not mark uninitialized if all the blocks in the
2682                  * extent have been removed.
2683                  */
2684                 if (uninitialized && num)
2685                         ext4_ext_mark_uninitialized(ex);
2686                 /*
2687                  * If the extent was completely released,
2688                  * we need to remove it from the leaf
2689                  */
2690                 if (num == 0) {
2691                         if (end != EXT_MAX_BLOCKS - 1) {
2692                                 /*
2693                                  * For hole punching, we need to scoot all the
2694                                  * extents up when an extent is removed so that
2695                                  * we dont have blank extents in the middle
2696                                  */
2697                                 memmove(ex, ex+1, (EXT_LAST_EXTENT(eh) - ex) *
2698                                         sizeof(struct ext4_extent));
2699
2700                                 /* Now get rid of the one at the end */
2701                                 memset(EXT_LAST_EXTENT(eh), 0,
2702                                         sizeof(struct ext4_extent));
2703                         }
2704                         le16_add_cpu(&eh->eh_entries, -1);
2705                 } else if (*partial_cluster > 0)
2706                         *partial_cluster = 0;
2707
2708                 err = ext4_ext_dirty(handle, inode, path + depth);
2709                 if (err)
2710                         goto out;
2711
2712                 ext_debug("new extent: %u:%u:%llu\n", ex_ee_block, num,
2713                                 ext4_ext_pblock(ex));
2714                 ex--;
2715                 ex_ee_block = le32_to_cpu(ex->ee_block);
2716                 ex_ee_len = ext4_ext_get_actual_len(ex);
2717         }
2718
2719         if (correct_index && eh->eh_entries)
2720                 err = ext4_ext_correct_indexes(handle, inode, path);
2721
2722         /*
2723          * Free the partial cluster only if the current extent does not
2724          * reference it. Otherwise we might free used cluster.
2725          */
2726         if (*partial_cluster > 0 &&
2727             (EXT4_B2C(sbi, ext4_ext_pblock(ex) + ex_ee_len - 1) !=
2728              *partial_cluster)) {
2729                 int flags = get_default_free_blocks_flags(inode);
2730
2731                 ext4_free_blocks(handle, inode, NULL,
2732                                  EXT4_C2B(sbi, *partial_cluster),
2733                                  sbi->s_cluster_ratio, flags);
2734                 *partial_cluster = 0;
2735         }
2736
2737         /* if this leaf is free, then we should
2738          * remove it from index block above */
2739         if (err == 0 && eh->eh_entries == 0 && path[depth].p_bh != NULL)
2740                 err = ext4_ext_rm_idx(handle, inode, path, depth);
2741
2742 out:
2743         return err;
2744 }
2745
2746 /*
2747  * ext4_ext_more_to_rm:
2748  * returns 1 if current index has to be freed (even partial)
2749  */
2750 static int
2751 ext4_ext_more_to_rm(struct ext4_ext_path *path)
2752 {
2753         BUG_ON(path->p_idx == NULL);
2754
2755         if (path->p_idx < EXT_FIRST_INDEX(path->p_hdr))
2756                 return 0;
2757
2758         /*
2759          * if truncate on deeper level happened, it wasn't partial,
2760          * so we have to consider current index for truncation
2761          */
2762         if (le16_to_cpu(path->p_hdr->eh_entries) == path->p_block)
2763                 return 0;
2764         return 1;
2765 }
2766
2767 int ext4_ext_remove_space(struct inode *inode, ext4_lblk_t start,
2768                           ext4_lblk_t end)
2769 {
2770         struct super_block *sb = inode->i_sb;
2771         int depth = ext_depth(inode);
2772         struct ext4_ext_path *path = NULL;
2773         long long partial_cluster = 0;
2774         handle_t *handle;
2775         int i = 0, err = 0;
2776
2777         ext_debug("truncate since %u to %u\n", start, end);
2778
2779         /* probably first extent we're gonna free will be last in block */
2780         handle = ext4_journal_start(inode, EXT4_HT_TRUNCATE, depth + 1);
2781         if (IS_ERR(handle))
2782                 return PTR_ERR(handle);
2783
2784 again:
2785         trace_ext4_ext_remove_space(inode, start, end, depth);
2786
2787         /*
2788          * Check if we are removing extents inside the extent tree. If that
2789          * is the case, we are going to punch a hole inside the extent tree
2790          * so we have to check whether we need to split the extent covering
2791          * the last block to remove so we can easily remove the part of it
2792          * in ext4_ext_rm_leaf().
2793          */
2794         if (end < EXT_MAX_BLOCKS - 1) {
2795                 struct ext4_extent *ex;
2796                 ext4_lblk_t ee_block;
2797
2798                 /* find extent for this block */
2799                 path = ext4_ext_find_extent(inode, end, NULL, EXT4_EX_NOCACHE);
2800                 if (IS_ERR(path)) {
2801                         ext4_journal_stop(handle);
2802                         return PTR_ERR(path);
2803                 }
2804                 depth = ext_depth(inode);
2805                 /* Leaf not may not exist only if inode has no blocks at all */
2806                 ex = path[depth].p_ext;
2807                 if (!ex) {
2808                         if (depth) {
2809                                 EXT4_ERROR_INODE(inode,
2810                                                  "path[%d].p_hdr == NULL",
2811                                                  depth);
2812                                 err = -EIO;
2813                         }
2814                         goto out;
2815                 }
2816
2817                 ee_block = le32_to_cpu(ex->ee_block);
2818
2819                 /*
2820                  * See if the last block is inside the extent, if so split
2821                  * the extent at 'end' block so we can easily remove the
2822                  * tail of the first part of the split extent in
2823                  * ext4_ext_rm_leaf().
2824                  */
2825                 if (end >= ee_block &&
2826                     end < ee_block + ext4_ext_get_actual_len(ex) - 1) {
2827                         int split_flag = 0;
2828
2829                         if (ext4_ext_is_uninitialized(ex))
2830                                 split_flag = EXT4_EXT_MARK_UNINIT1 |
2831                                              EXT4_EXT_MARK_UNINIT2;
2832
2833                         /*
2834                          * Split the extent in two so that 'end' is the last
2835                          * block in the first new extent. Also we should not
2836                          * fail removing space due to ENOSPC so try to use
2837                          * reserved block if that happens.
2838                          */
2839                         err = ext4_split_extent_at(handle, inode, path,
2840                                         end + 1, split_flag,
2841                                         EXT4_EX_NOCACHE |
2842                                         EXT4_GET_BLOCKS_PRE_IO |
2843                                         EXT4_GET_BLOCKS_METADATA_NOFAIL);
2844
2845                         if (err < 0)
2846                                 goto out;
2847                 }
2848         }
2849         /*
2850          * We start scanning from right side, freeing all the blocks
2851          * after i_size and walking into the tree depth-wise.
2852          */
2853         depth = ext_depth(inode);
2854         if (path) {
2855                 int k = i = depth;
2856                 while (--k > 0)
2857                         path[k].p_block =
2858                                 le16_to_cpu(path[k].p_hdr->eh_entries)+1;
2859         } else {
2860                 path = kzalloc(sizeof(struct ext4_ext_path) * (depth + 1),
2861                                GFP_NOFS);
2862                 if (path == NULL) {
2863                         ext4_journal_stop(handle);
2864                         return -ENOMEM;
2865                 }
2866                 path[0].p_depth = depth;
2867                 path[0].p_hdr = ext_inode_hdr(inode);
2868                 i = 0;
2869
2870                 if (ext4_ext_check(inode, path[0].p_hdr, depth, 0)) {
2871                         err = -EIO;
2872                         goto out;
2873                 }
2874         }
2875         err = 0;
2876
2877         while (i >= 0 && err == 0) {
2878                 if (i == depth) {
2879                         /* this is leaf block */
2880                         err = ext4_ext_rm_leaf(handle, inode, path,
2881                                                &partial_cluster, start,
2882                                                end);
2883                         /* root level has p_bh == NULL, brelse() eats this */
2884                         brelse(path[i].p_bh);
2885                         path[i].p_bh = NULL;
2886                         i--;
2887                         continue;
2888                 }
2889
2890                 /* this is index block */
2891                 if (!path[i].p_hdr) {
2892                         ext_debug("initialize header\n");
2893                         path[i].p_hdr = ext_block_hdr(path[i].p_bh);
2894                 }
2895
2896                 if (!path[i].p_idx) {
2897                         /* this level hasn't been touched yet */
2898                         path[i].p_idx = EXT_LAST_INDEX(path[i].p_hdr);
2899                         path[i].p_block = le16_to_cpu(path[i].p_hdr->eh_entries)+1;
2900                         ext_debug("init index ptr: hdr 0x%p, num %d\n",
2901                                   path[i].p_hdr,
2902                                   le16_to_cpu(path[i].p_hdr->eh_entries));
2903                 } else {
2904                         /* we were already here, see at next index */
2905                         path[i].p_idx--;
2906                 }
2907
2908                 ext_debug("level %d - index, first 0x%p, cur 0x%p\n",
2909                                 i, EXT_FIRST_INDEX(path[i].p_hdr),
2910                                 path[i].p_idx);
2911                 if (ext4_ext_more_to_rm(path + i)) {
2912                         struct buffer_head *bh;
2913                         /* go to the next level */
2914                         ext_debug("move to level %d (block %llu)\n",
2915                                   i + 1, ext4_idx_pblock(path[i].p_idx));
2916                         memset(path + i + 1, 0, sizeof(*path));
2917                         bh = read_extent_tree_block(inode,
2918                                 ext4_idx_pblock(path[i].p_idx), depth - i - 1,
2919                                 EXT4_EX_NOCACHE);
2920                         if (IS_ERR(bh)) {
2921                                 /* should we reset i_size? */
2922                                 err = PTR_ERR(bh);
2923                                 break;
2924                         }
2925                         /* Yield here to deal with large extent trees.
2926                          * Should be a no-op if we did IO above. */
2927                         cond_resched();
2928                         if (WARN_ON(i + 1 > depth)) {
2929                                 err = -EIO;
2930                                 break;
2931                         }
2932                         path[i + 1].p_bh = bh;
2933
2934                         /* save actual number of indexes since this
2935                          * number is changed at the next iteration */
2936                         path[i].p_block = le16_to_cpu(path[i].p_hdr->eh_entries);
2937                         i++;
2938                 } else {
2939                         /* we finished processing this index, go up */
2940                         if (path[i].p_hdr->eh_entries == 0 && i > 0) {
2941                                 /* index is empty, remove it;
2942                                  * handle must be already prepared by the
2943                                  * truncatei_leaf() */
2944                                 err = ext4_ext_rm_idx(handle, inode, path, i);
2945                         }
2946                         /* root level has p_bh == NULL, brelse() eats this */
2947                         brelse(path[i].p_bh);
2948                         path[i].p_bh = NULL;
2949                         i--;
2950                         ext_debug("return to level %d\n", i);
2951                 }
2952         }
2953
2954         trace_ext4_ext_remove_space_done(inode, start, end, depth,
2955                         partial_cluster, path->p_hdr->eh_entries);
2956
2957         /* If we still have something in the partial cluster and we have removed
2958          * even the first extent, then we should free the blocks in the partial
2959          * cluster as well. */
2960         if (partial_cluster > 0 && path->p_hdr->eh_entries == 0) {
2961                 int flags = get_default_free_blocks_flags(inode);
2962
2963                 ext4_free_blocks(handle, inode, NULL,
2964                                  EXT4_C2B(EXT4_SB(sb), partial_cluster),
2965                                  EXT4_SB(sb)->s_cluster_ratio, flags);
2966                 partial_cluster = 0;
2967         }
2968
2969         /* TODO: flexible tree reduction should be here */
2970         if (path->p_hdr->eh_entries == 0) {
2971                 /*
2972                  * truncate to zero freed all the tree,
2973                  * so we need to correct eh_depth
2974                  */
2975                 err = ext4_ext_get_access(handle, inode, path);
2976                 if (err == 0) {
2977                         ext_inode_hdr(inode)->eh_depth = 0;
2978                         ext_inode_hdr(inode)->eh_max =
2979                                 cpu_to_le16(ext4_ext_space_root(inode, 0));
2980                         err = ext4_ext_dirty(handle, inode, path);
2981                 }
2982         }
2983 out:
2984         ext4_ext_drop_refs(path);
2985         kfree(path);
2986         if (err == -EAGAIN) {
2987                 path = NULL;
2988                 goto again;
2989         }
2990         ext4_journal_stop(handle);
2991
2992         return err;
2993 }
2994
2995 /*
2996  * called at mount time
2997  */
2998 void ext4_ext_init(struct super_block *sb)
2999 {
3000         /*
3001          * possible initialization would be here
3002          */
3003
3004         if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_EXTENTS)) {
3005 #if defined(AGGRESSIVE_TEST) || defined(CHECK_BINSEARCH) || defined(EXTENTS_STATS)
3006                 printk(KERN_INFO "EXT4-fs: file extents enabled"
3007 #ifdef AGGRESSIVE_TEST
3008                        ", aggressive tests"
3009 #endif
3010 #ifdef CHECK_BINSEARCH
3011                        ", check binsearch"
3012 #endif
3013 #ifdef EXTENTS_STATS
3014                        ", stats"
3015 #endif
3016                        "\n");
3017 #endif
3018 #ifdef EXTENTS_STATS
3019                 spin_lock_init(&EXT4_SB(sb)->s_ext_stats_lock);
3020                 EXT4_SB(sb)->s_ext_min = 1 << 30;
3021                 EXT4_SB(sb)->s_ext_max = 0;
3022 #endif
3023         }
3024 }
3025
3026 /*
3027  * called at umount time
3028  */
3029 void ext4_ext_release(struct super_block *sb)
3030 {
3031         if (!EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_EXTENTS))
3032                 return;
3033
3034 #ifdef EXTENTS_STATS
3035         if (EXT4_SB(sb)->s_ext_blocks && EXT4_SB(sb)->s_ext_extents) {
3036                 struct ext4_sb_info *sbi = EXT4_SB(sb);
3037                 printk(KERN_ERR "EXT4-fs: %lu blocks in %lu extents (%lu ave)\n",
3038                         sbi->s_ext_blocks, sbi->s_ext_extents,
3039                         sbi->s_ext_blocks / sbi->s_ext_extents);
3040                 printk(KERN_ERR "EXT4-fs: extents: %lu min, %lu max, max depth %lu\n",
3041                         sbi->s_ext_min, sbi->s_ext_max, sbi->s_depth_max);
3042         }
3043 #endif
3044 }
3045
3046 static int ext4_zeroout_es(struct inode *inode, struct ext4_extent *ex)
3047 {
3048         ext4_lblk_t  ee_block;
3049         ext4_fsblk_t ee_pblock;
3050         unsigned int ee_len;
3051
3052         ee_block  = le32_to_cpu(ex->ee_block);
3053         ee_len    = ext4_ext_get_actual_len(ex);
3054         ee_pblock = ext4_ext_pblock(ex);
3055
3056         if (ee_len == 0)
3057                 return 0;
3058
3059         return ext4_es_insert_extent(inode, ee_block, ee_len, ee_pblock,
3060                                      EXTENT_STATUS_WRITTEN);
3061 }
3062
3063 /* FIXME!! we need to try to merge to left or right after zero-out  */
3064 static int ext4_ext_zeroout(struct inode *inode, struct ext4_extent *ex)
3065 {
3066         ext4_fsblk_t ee_pblock;
3067         unsigned int ee_len;
3068         int ret;
3069
3070         ee_len    = ext4_ext_get_actual_len(ex);
3071         ee_pblock = ext4_ext_pblock(ex);
3072
3073         ret = sb_issue_zeroout(inode->i_sb, ee_pblock, ee_len, GFP_NOFS);
3074         if (ret > 0)
3075                 ret = 0;
3076
3077         return ret;
3078 }
3079
3080 /*
3081  * ext4_split_extent_at() splits an extent at given block.
3082  *
3083  * @handle: the journal handle
3084  * @inode: the file inode
3085  * @path: the path to the extent
3086  * @split: the logical block where the extent is splitted.
3087  * @split_flags: indicates if the extent could be zeroout if split fails, and
3088  *               the states(init or uninit) of new extents.
3089  * @flags: flags used to insert new extent to extent tree.
3090  *
3091  *
3092  * Splits extent [a, b] into two extents [a, @split) and [@split, b], states
3093  * of which are deterimined by split_flag.
3094  *
3095  * There are two cases:
3096  *  a> the extent are splitted into two extent.
3097  *  b> split is not needed, and just mark the extent.
3098  *
3099  * return 0 on success.
3100  */
3101 static int ext4_split_extent_at(handle_t *handle,
3102                              struct inode *inode,
3103                              struct ext4_ext_path *path,
3104                              ext4_lblk_t split,
3105                              int split_flag,
3106                              int flags)
3107 {
3108         ext4_fsblk_t newblock;
3109         ext4_lblk_t ee_block;
3110         struct ext4_extent *ex, newex, orig_ex, zero_ex;
3111         struct ext4_extent *ex2 = NULL;
3112         unsigned int ee_len, depth;
3113         int err = 0;
3114
3115         BUG_ON((split_flag & (EXT4_EXT_DATA_VALID1 | EXT4_EXT_DATA_VALID2)) ==
3116                (EXT4_EXT_DATA_VALID1 | EXT4_EXT_DATA_VALID2));
3117
3118         ext_debug("ext4_split_extents_at: inode %lu, logical"
3119                 "block %llu\n", inode->i_ino, (unsigned long long)split);
3120
3121         ext4_ext_show_leaf(inode, path);
3122
3123         depth = ext_depth(inode);
3124         ex = path[depth].p_ext;
3125         ee_block = le32_to_cpu(ex->ee_block);
3126         ee_len = ext4_ext_get_actual_len(ex);
3127         newblock = split - ee_block + ext4_ext_pblock(ex);
3128
3129         BUG_ON(split < ee_block || split >= (ee_block + ee_len));
3130         BUG_ON(!ext4_ext_is_uninitialized(ex) &&
3131                split_flag & (EXT4_EXT_MAY_ZEROOUT |
3132                              EXT4_EXT_MARK_UNINIT1 |
3133                              EXT4_EXT_MARK_UNINIT2));
3134
3135         err = ext4_ext_get_access(handle, inode, path + depth);
3136         if (err)
3137                 goto out;
3138
3139         if (split == ee_block) {
3140                 /*
3141                  * case b: block @split is the block that the extent begins with
3142                  * then we just change the state of the extent, and splitting
3143                  * is not needed.
3144                  */
3145                 if (split_flag & EXT4_EXT_MARK_UNINIT2)
3146                         ext4_ext_mark_uninitialized(ex);
3147                 else
3148                         ext4_ext_mark_initialized(ex);
3149
3150                 if (!(flags & EXT4_GET_BLOCKS_PRE_IO))
3151                         ext4_ext_try_to_merge(handle, inode, path, ex);
3152
3153                 err = ext4_ext_dirty(handle, inode, path + path->p_depth);
3154                 goto out;
3155         }
3156
3157         /* case a */
3158         memcpy(&orig_ex, ex, sizeof(orig_ex));
3159         ex->ee_len = cpu_to_le16(split - ee_block);
3160         if (split_flag & EXT4_EXT_MARK_UNINIT1)
3161                 ext4_ext_mark_uninitialized(ex);
3162
3163         /*
3164          * path may lead to new leaf, not to original leaf any more
3165          * after ext4_ext_insert_extent() returns,
3166          */
3167         err = ext4_ext_dirty(handle, inode, path + depth);
3168         if (err)
3169                 goto fix_extent_len;
3170
3171         ex2 = &newex;
3172         ex2->ee_block = cpu_to_le32(split);
3173         ex2->ee_len   = cpu_to_le16(ee_len - (split - ee_block));
3174         ext4_ext_store_pblock(ex2, newblock);
3175         if (split_flag & EXT4_EXT_MARK_UNINIT2)
3176                 ext4_ext_mark_uninitialized(ex2);
3177
3178         err = ext4_ext_insert_extent(handle, inode, path, &newex, flags);
3179         if (err == -ENOSPC && (EXT4_EXT_MAY_ZEROOUT & split_flag)) {
3180                 if (split_flag & (EXT4_EXT_DATA_VALID1|EXT4_EXT_DATA_VALID2)) {
3181                         if (split_flag & EXT4_EXT_DATA_VALID1) {
3182                                 err = ext4_ext_zeroout(inode, ex2);
3183                                 zero_ex.ee_block = ex2->ee_block;
3184                                 zero_ex.ee_len = cpu_to_le16(
3185                                                 ext4_ext_get_actual_len(ex2));
3186                                 ext4_ext_store_pblock(&zero_ex,
3187                                                       ext4_ext_pblock(ex2));
3188                         } else {
3189                                 err = ext4_ext_zeroout(inode, ex);
3190                                 zero_ex.ee_block = ex->ee_block;
3191                                 zero_ex.ee_len = cpu_to_le16(
3192                                                 ext4_ext_get_actual_len(ex));
3193                                 ext4_ext_store_pblock(&zero_ex,
3194                                                       ext4_ext_pblock(ex));
3195                         }
3196                 } else {
3197                         err = ext4_ext_zeroout(inode, &orig_ex);
3198                         zero_ex.ee_block = orig_ex.ee_block;
3199                         zero_ex.ee_len = cpu_to_le16(
3200                                                 ext4_ext_get_actual_len(&orig_ex));
3201                         ext4_ext_store_pblock(&zero_ex,
3202                                               ext4_ext_pblock(&orig_ex));
3203                 }
3204
3205                 if (err)
3206                         goto fix_extent_len;
3207                 /* update the extent length and mark as initialized */
3208                 ex->ee_len = cpu_to_le16(ee_len);
3209                 ext4_ext_try_to_merge(handle, inode, path, ex);
3210                 err = ext4_ext_dirty(handle, inode, path + path->p_depth);
3211                 if (err)
3212                         goto fix_extent_len;
3213
3214                 /* update extent status tree */
3215                 err = ext4_zeroout_es(inode, &zero_ex);
3216
3217                 goto out;
3218         } else if (err)
3219                 goto fix_extent_len;
3220
3221 out:
3222         ext4_ext_show_leaf(inode, path);
3223         return err;
3224
3225 fix_extent_len:
3226         ex->ee_len = orig_ex.ee_len;
3227         ext4_ext_dirty(handle, inode, path + depth);
3228         return err;
3229 }
3230
3231 /*
3232  * ext4_split_extents() splits an extent and mark extent which is covered
3233  * by @map as split_flags indicates
3234  *
3235  * It may result in splitting the extent into multiple extents (up to three)
3236  * There are three possibilities:
3237  *   a> There is no split required
3238  *   b> Splits in two extents: Split is happening at either end of the extent
3239  *   c> Splits in three extents: Somone is splitting in middle of the extent
3240  *
3241  */
3242 static int ext4_split_extent(handle_t *handle,
3243                               struct inode *inode,
3244                               struct ext4_ext_path *path,
3245                               struct ext4_map_blocks *map,
3246                               int split_flag,
3247                               int flags)
3248 {
3249         ext4_lblk_t ee_block;
3250         struct ext4_extent *ex;
3251         unsigned int ee_len, depth;
3252         int err = 0;
3253         int uninitialized;
3254         int split_flag1, flags1;
3255         int allocated = map->m_len;
3256
3257         depth = ext_depth(inode);
3258         ex = path[depth].p_ext;
3259         ee_block = le32_to_cpu(ex->ee_block);
3260         ee_len = ext4_ext_get_actual_len(ex);
3261         uninitialized = ext4_ext_is_uninitialized(ex);
3262
3263         if (map->m_lblk + map->m_len < ee_block + ee_len) {
3264                 split_flag1 = split_flag & EXT4_EXT_MAY_ZEROOUT;
3265                 flags1 = flags | EXT4_GET_BLOCKS_PRE_IO;
3266                 if (uninitialized)
3267                         split_flag1 |= EXT4_EXT_MARK_UNINIT1 |
3268                                        EXT4_EXT_MARK_UNINIT2;
3269                 if (split_flag & EXT4_EXT_DATA_VALID2)
3270                         split_flag1 |= EXT4_EXT_DATA_VALID1;
3271                 err = ext4_split_extent_at(handle, inode, path,
3272                                 map->m_lblk + map->m_len, split_flag1, flags1);
3273                 if (err)
3274                         goto out;
3275         } else {
3276                 allocated = ee_len - (map->m_lblk - ee_block);
3277         }
3278         /*
3279          * Update path is required because previous ext4_split_extent_at() may
3280          * result in split of original leaf or extent zeroout.
3281          */
3282         ext4_ext_drop_refs(path);
3283         path = ext4_ext_find_extent(inode, map->m_lblk, path, 0);
3284         if (IS_ERR(path))
3285                 return PTR_ERR(path);
3286         depth = ext_depth(inode);
3287         ex = path[depth].p_ext;
3288         uninitialized = ext4_ext_is_uninitialized(ex);
3289         split_flag1 = 0;
3290
3291         if (map->m_lblk >= ee_block) {
3292                 split_flag1 = split_flag & EXT4_EXT_DATA_VALID2;
3293                 if (uninitialized) {
3294                         split_flag1 |= EXT4_EXT_MARK_UNINIT1;
3295                         split_flag1 |= split_flag & (EXT4_EXT_MAY_ZEROOUT |
3296                                                      EXT4_EXT_MARK_UNINIT2);
3297                 }
3298                 err = ext4_split_extent_at(handle, inode, path,
3299                                 map->m_lblk, split_flag1, flags);
3300                 if (err)
3301                         goto out;
3302         }
3303
3304         ext4_ext_show_leaf(inode, path);
3305 out:
3306         return err ? err : allocated;
3307 }
3308
3309 /*
3310  * This function is called by ext4_ext_map_blocks() if someone tries to write
3311  * to an uninitialized extent. It may result in splitting the uninitialized
3312  * extent into multiple extents (up to three - one initialized and two
3313  * uninitialized).
3314  * There are three possibilities:
3315  *   a> There is no split required: Entire extent should be initialized
3316  *   b> Splits in two extents: Write is happening at either end of the extent
3317  *   c> Splits in three extents: Somone is writing in middle of the extent
3318  *
3319  * Pre-conditions:
3320  *  - The extent pointed to by 'path' is uninitialized.
3321  *  - The extent pointed to by 'path' contains a superset
3322  *    of the logical span [map->m_lblk, map->m_lblk + map->m_len).
3323  *
3324  * Post-conditions on success:
3325  *  - the returned value is the number of blocks beyond map->l_lblk
3326  *    that are allocated and initialized.
3327  *    It is guaranteed to be >= map->m_len.
3328  */
3329 static int ext4_ext_convert_to_initialized(handle_t *handle,
3330                                            struct inode *inode,
3331                                            struct ext4_map_blocks *map,
3332                                            struct ext4_ext_path *path,
3333                                            int flags)
3334 {
3335         struct ext4_sb_info *sbi;
3336         struct ext4_extent_header *eh;
3337         struct ext4_map_blocks split_map;
3338         struct ext4_extent zero_ex;
3339         struct ext4_extent *ex, *abut_ex;
3340         ext4_lblk_t ee_block, eof_block;
3341         unsigned int ee_len, depth, map_len = map->m_len;
3342         int allocated = 0, max_zeroout = 0;
3343         int err = 0;
3344         int split_flag = 0;
3345
3346         ext_debug("ext4_ext_convert_to_initialized: inode %lu, logical"
3347                 "block %llu, max_blocks %u\n", inode->i_ino,
3348                 (unsigned long long)map->m_lblk, map_len);
3349
3350         sbi = EXT4_SB(inode->i_sb);
3351         eof_block = (inode->i_size + inode->i_sb->s_blocksize - 1) >>
3352                 inode->i_sb->s_blocksize_bits;
3353         if (eof_block < map->m_lblk + map_len)
3354                 eof_block = map->m_lblk + map_len;
3355
3356         depth = ext_depth(inode);
3357         eh = path[depth].p_hdr;
3358         ex = path[depth].p_ext;
3359         ee_block = le32_to_cpu(ex->ee_block);
3360         ee_len = ext4_ext_get_actual_len(ex);
3361         zero_ex.ee_len = 0;
3362
3363         trace_ext4_ext_convert_to_initialized_enter(inode, map, ex);
3364
3365         /* Pre-conditions */
3366         BUG_ON(!ext4_ext_is_uninitialized(ex));
3367         BUG_ON(!in_range(map->m_lblk, ee_block, ee_len));
3368
3369         /*
3370          * Attempt to transfer newly initialized blocks from the currently
3371          * uninitialized extent to its neighbor. This is much cheaper
3372          * than an insertion followed by a merge as those involve costly
3373          * memmove() calls. Transferring to the left is the common case in
3374          * steady state for workloads doing fallocate(FALLOC_FL_KEEP_SIZE)
3375          * followed by append writes.
3376          *
3377          * Limitations of the current logic:
3378          *  - L1: we do not deal with writes covering the whole extent.
3379          *    This would require removing the extent if the transfer
3380          *    is possible.
3381          *  - L2: we only attempt to merge with an extent stored in the
3382          *    same extent tree node.
3383          */
3384         if ((map->m_lblk == ee_block) &&
3385                 /* See if we can merge left */
3386                 (map_len < ee_len) &&           /*L1*/
3387                 (ex > EXT_FIRST_EXTENT(eh))) {  /*L2*/
3388                 ext4_lblk_t prev_lblk;
3389                 ext4_fsblk_t prev_pblk, ee_pblk;
3390                 unsigned int prev_len;
3391
3392                 abut_ex = ex - 1;
3393                 prev_lblk = le32_to_cpu(abut_ex->ee_block);
3394                 prev_len = ext4_ext_get_actual_len(abut_ex);
3395                 prev_pblk = ext4_ext_pblock(abut_ex);
3396                 ee_pblk = ext4_ext_pblock(ex);
3397
3398                 /*
3399                  * A transfer of blocks from 'ex' to 'abut_ex' is allowed
3400                  * upon those conditions:
3401                  * - C1: abut_ex is initialized,
3402                  * - C2: abut_ex is logically abutting ex,
3403                  * - C3: abut_ex is physically abutting ex,
3404                  * - C4: abut_ex can receive the additional blocks without
3405                  *   overflowing the (initialized) length limit.
3406                  */
3407                 if ((!ext4_ext_is_uninitialized(abut_ex)) &&            /*C1*/
3408                         ((prev_lblk + prev_len) == ee_block) &&         /*C2*/
3409                         ((prev_pblk + prev_len) == ee_pblk) &&          /*C3*/
3410                         (prev_len < (EXT_INIT_MAX_LEN - map_len))) {    /*C4*/
3411                         err = ext4_ext_get_access(handle, inode, path + depth);
3412                         if (err)
3413                                 goto out;
3414
3415                         trace_ext4_ext_convert_to_initialized_fastpath(inode,
3416                                 map, ex, abut_ex);
3417
3418                         /* Shift the start of ex by 'map_len' blocks */
3419                         ex->ee_block = cpu_to_le32(ee_block + map_len);
3420                         ext4_ext_store_pblock(ex, ee_pblk + map_len);
3421                         ex->ee_len = cpu_to_le16(ee_len - map_len);
3422                         ext4_ext_mark_uninitialized(ex); /* Restore the flag */
3423
3424                         /* Extend abut_ex by 'map_len' blocks */
3425                         abut_ex->ee_len = cpu_to_le16(prev_len + map_len);
3426
3427                         /* Result: number of initialized blocks past m_lblk */
3428                         allocated = map_len;
3429                 }
3430         } else if (((map->m_lblk + map_len) == (ee_block + ee_len)) &&
3431                    (map_len < ee_len) &&        /*L1*/
3432                    ex < EXT_LAST_EXTENT(eh)) {  /*L2*/
3433                 /* See if we can merge right */
3434                 ext4_lblk_t next_lblk;
3435                 ext4_fsblk_t next_pblk, ee_pblk;
3436                 unsigned int next_len;
3437
3438                 abut_ex = ex + 1;
3439                 next_lblk = le32_to_cpu(abut_ex->ee_block);
3440                 next_len = ext4_ext_get_actual_len(abut_ex);
3441                 next_pblk = ext4_ext_pblock(abut_ex);
3442                 ee_pblk = ext4_ext_pblock(ex);
3443
3444                 /*
3445                  * A transfer of blocks from 'ex' to 'abut_ex' is allowed
3446                  * upon those conditions:
3447                  * - C1: abut_ex is initialized,
3448                  * - C2: abut_ex is logically abutting ex,
3449                  * - C3: abut_ex is physically abutting ex,
3450                  * - C4: abut_ex can receive the additional blocks without
3451                  *   overflowing the (initialized) length limit.
3452                  */
3453                 if ((!ext4_ext_is_uninitialized(abut_ex)) &&            /*C1*/
3454                     ((map->m_lblk + map_len) == next_lblk) &&           /*C2*/
3455                     ((ee_pblk + ee_len) == next_pblk) &&                /*C3*/
3456                     (next_len < (EXT_INIT_MAX_LEN - map_len))) {        /*C4*/
3457                         err = ext4_ext_get_access(handle, inode, path + depth);
3458                         if (err)
3459                                 goto out;
3460
3461                         trace_ext4_ext_convert_to_initialized_fastpath(inode,
3462                                 map, ex, abut_ex);
3463
3464                         /* Shift the start of abut_ex by 'map_len' blocks */
3465                         abut_ex->ee_block = cpu_to_le32(next_lblk - map_len);
3466                         ext4_ext_store_pblock(abut_ex, next_pblk - map_len);
3467                         ex->ee_len = cpu_to_le16(ee_len - map_len);
3468                         ext4_ext_mark_uninitialized(ex); /* Restore the flag */
3469
3470                         /* Extend abut_ex by 'map_len' blocks */
3471                         abut_ex->ee_len = cpu_to_le16(next_len + map_len);
3472
3473                         /* Result: number of initialized blocks past m_lblk */
3474                         allocated = map_len;
3475                 }
3476         }
3477         if (allocated) {
3478                 /* Mark the block containing both extents as dirty */
3479                 ext4_ext_dirty(handle, inode, path + depth);
3480
3481                 /* Update path to point to the right extent */
3482                 path[depth].p_ext = abut_ex;
3483                 goto out;
3484         } else
3485                 allocated = ee_len - (map->m_lblk - ee_block);
3486
3487         WARN_ON(map->m_lblk < ee_block);
3488         /*
3489          * It is safe to convert extent to initialized via explicit
3490          * zeroout only if extent is fully insde i_size or new_size.
3491          */
3492         split_flag |= ee_block + ee_len <= eof_block ? EXT4_EXT_MAY_ZEROOUT : 0;
3493
3494         if (EXT4_EXT_MAY_ZEROOUT & split_flag)
3495                 max_zeroout = sbi->s_extent_max_zeroout_kb >>
3496                         (inode->i_sb->s_blocksize_bits - 10);
3497
3498         /* If extent is less than s_max_zeroout_kb, zeroout directly */
3499         if (max_zeroout && (ee_len <= max_zeroout)) {
3500                 err = ext4_ext_zeroout(inode, ex);
3501                 if (err)
3502                         goto out;
3503                 zero_ex.ee_block = ex->ee_block;
3504                 zero_ex.ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex));
3505                 ext4_ext_store_pblock(&zero_ex, ext4_ext_pblock(ex));
3506
3507                 err = ext4_ext_get_access(handle, inode, path + depth);
3508                 if (err)
3509                         goto out;
3510                 ext4_ext_mark_initialized(ex);
3511                 ext4_ext_try_to_merge(handle, inode, path, ex);
3512                 err = ext4_ext_dirty(handle, inode, path + path->p_depth);
3513                 goto out;
3514         }
3515
3516         /*
3517          * four cases:
3518          * 1. split the extent into three extents.
3519          * 2. split the extent into two extents, zeroout the first half.
3520          * 3. split the extent into two extents, zeroout the second half.
3521          * 4. split the extent into two extents with out zeroout.
3522          */
3523         split_map.m_lblk = map->m_lblk;
3524         split_map.m_len = map->m_len;
3525
3526         if (max_zeroout && (allocated > map->m_len)) {
3527                 if (allocated <= max_zeroout) {
3528                         /* case 3 */
3529                         zero_ex.ee_block =
3530                                          cpu_to_le32(map->m_lblk);
3531                         zero_ex.ee_len = cpu_to_le16(allocated);
3532                         ext4_ext_store_pblock(&zero_ex,
3533                                 ext4_ext_pblock(ex) + map->m_lblk - ee_block);
3534                         err = ext4_ext_zeroout(inode, &zero_ex);
3535                         if (err)
3536                                 goto out;
3537                         split_map.m_lblk = map->m_lblk;
3538                         split_map.m_len = allocated;
3539                 } else if (map->m_lblk - ee_block + map->m_len < max_zeroout) {
3540                         /* case 2 */
3541                         if (map->m_lblk != ee_block) {
3542                                 zero_ex.ee_block = ex->ee_block;
3543                                 zero_ex.ee_len = cpu_to_le16(map->m_lblk -
3544                                                         ee_block);
3545                                 ext4_ext_store_pblock(&zero_ex,
3546                                                       ext4_ext_pblock(ex));
3547                                 err = ext4_ext_zeroout(inode, &zero_ex);
3548                                 if (err)
3549                                         goto out;
3550                         }
3551
3552                         split_map.m_lblk = ee_block;
3553                         split_map.m_len = map->m_lblk - ee_block + map->m_len;
3554                         allocated = map->m_len;
3555                 }
3556         }
3557
3558         allocated = ext4_split_extent(handle, inode, path,
3559                                       &split_map, split_flag, flags);
3560         if (allocated < 0)
3561                 err = allocated;
3562
3563 out:
3564         /* If we have gotten a failure, don't zero out status tree */
3565         if (!err)
3566                 err = ext4_zeroout_es(inode, &zero_ex);
3567         return err ? err : allocated;
3568 }
3569
3570 /*
3571  * This function is called by ext4_ext_map_blocks() from
3572  * ext4_get_blocks_dio_write() when DIO to write
3573  * to an uninitialized extent.
3574  *
3575  * Writing to an uninitialized extent may result in splitting the uninitialized
3576  * extent into multiple initialized/uninitialized extents (up to three)
3577  * There are three possibilities:
3578  *   a> There is no split required: Entire extent should be uninitialized
3579  *   b> Splits in two extents: Write is happening at either end of the extent
3580  *   c> Splits in three extents: Somone is writing in middle of the extent
3581  *
3582  * One of more index blocks maybe needed if the extent tree grow after
3583  * the uninitialized extent split. To prevent ENOSPC occur at the IO
3584  * complete, we need to split the uninitialized extent before DIO submit
3585  * the IO. The uninitialized extent called at this time will be split
3586  * into three uninitialized extent(at most). After IO complete, the part
3587  * being filled will be convert to initialized by the end_io callback function
3588  * via ext4_convert_unwritten_extents().
3589  *
3590  * Returns the size of uninitialized extent to be written on success.
3591  */
3592 static int ext4_split_unwritten_extents(handle_t *handle,
3593                                         struct inode *inode,
3594                                         struct ext4_map_blocks *map,
3595                                         struct ext4_ext_path *path,
3596                                         int flags)
3597 {
3598         ext4_lblk_t eof_block;
3599         ext4_lblk_t ee_block;
3600         struct ext4_extent *ex;
3601         unsigned int ee_len;
3602         int split_flag = 0, depth;
3603
3604         ext_debug("ext4_split_unwritten_extents: inode %lu, logical"
3605                 "block %llu, max_blocks %u\n", inode->i_ino,
3606                 (unsigned long long)map->m_lblk, map->m_len);
3607
3608         eof_block = (inode->i_size + inode->i_sb->s_blocksize - 1) >>
3609                 inode->i_sb->s_blocksize_bits;
3610         if (eof_block < map->m_lblk + map->m_len)
3611                 eof_block = map->m_lblk + map->m_len;
3612         /*
3613          * It is safe to convert extent to initialized via explicit
3614          * zeroout only if extent is fully insde i_size or new_size.
3615          */
3616         depth = ext_depth(inode);
3617         ex = path[depth].p_ext;
3618         ee_block = le32_to_cpu(ex->ee_block);
3619         ee_len = ext4_ext_get_actual_len(ex);
3620
3621         split_flag |= ee_block + ee_len <= eof_block ? EXT4_EXT_MAY_ZEROOUT : 0;
3622         split_flag |= EXT4_EXT_MARK_UNINIT2;
3623         if (flags & EXT4_GET_BLOCKS_CONVERT)
3624                 split_flag |= EXT4_EXT_DATA_VALID2;
3625         flags |= EXT4_GET_BLOCKS_PRE_IO;
3626         return ext4_split_extent(handle, inode, path, map, split_flag, flags);
3627 }
3628
3629 static int ext4_convert_unwritten_extents_endio(handle_t *handle,
3630                                                 struct inode *inode,
3631                                                 struct ext4_map_blocks *map,
3632                                                 struct ext4_ext_path *path)
3633 {
3634         struct ext4_extent *ex;
3635         ext4_lblk_t ee_block;
3636         unsigned int ee_len;
3637         int depth;
3638         int err = 0;
3639
3640         depth = ext_depth(inode);
3641         ex = path[depth].p_ext;
3642         ee_block = le32_to_cpu(ex->ee_block);
3643         ee_len = ext4_ext_get_actual_len(ex);
3644
3645         ext_debug("ext4_convert_unwritten_extents_endio: inode %lu, logical"
3646                 "block %llu, max_blocks %u\n", inode->i_ino,
3647                   (unsigned long long)ee_block, ee_len);
3648
3649         /* If extent is larger than requested it is a clear sign that we still
3650          * have some extent state machine issues left. So extent_split is still
3651          * required.
3652          * TODO: Once all related issues will be fixed this situation should be
3653          * illegal.
3654          */
3655         if (ee_block != map->m_lblk || ee_len > map->m_len) {
3656 #ifdef EXT4_DEBUG
3657                 ext4_warning("Inode (%ld) finished: extent logical block %llu,"
3658                              " len %u; IO logical block %llu, len %u\n",
3659                              inode->i_ino, (unsigned long long)ee_block, ee_len,
3660                              (unsigned long long)map->m_lblk, map->m_len);
3661 #endif
3662                 err = ext4_split_unwritten_extents(handle, inode, map, path,
3663                                                    EXT4_GET_BLOCKS_CONVERT);
3664                 if (err < 0)
3665                         goto out;
3666                 ext4_ext_drop_refs(path);
3667                 path = ext4_ext_find_extent(inode, map->m_lblk, path, 0);
3668                 if (IS_ERR(path)) {
3669                         err = PTR_ERR(path);
3670                         goto out;
3671                 }
3672                 depth = ext_depth(inode);
3673                 ex = path[depth].p_ext;
3674         }
3675
3676         err = ext4_ext_get_access(handle, inode, path + depth);
3677         if (err)
3678                 goto out;
3679         /* first mark the extent as initialized */
3680         ext4_ext_mark_initialized(ex);
3681
3682         /* note: ext4_ext_correct_indexes() isn't needed here because
3683          * borders are not changed
3684          */
3685         ext4_ext_try_to_merge(handle, inode, path, ex);
3686
3687         /* Mark modified extent as dirty */
3688         err = ext4_ext_dirty(handle, inode, path + path->p_depth);
3689 out:
3690         ext4_ext_show_leaf(inode, path);
3691         return err;
3692 }
3693
3694 static void unmap_underlying_metadata_blocks(struct block_device *bdev,
3695                         sector_t block, int count)
3696 {
3697         int i;
3698         for (i = 0; i < count; i++)
3699                 unmap_underlying_metadata(bdev, block + i);
3700 }
3701
3702 /*
3703  * Handle EOFBLOCKS_FL flag, clearing it if necessary
3704  */
3705 static int check_eofblocks_fl(handle_t *handle, struct inode *inode,
3706                               ext4_lblk_t lblk,
3707                               struct ext4_ext_path *path,
3708                               unsigned int len)
3709 {
3710         int i, depth;
3711         struct ext4_extent_header *eh;
3712         struct ext4_extent *last_ex;
3713
3714         if (!ext4_test_inode_flag(inode, EXT4_INODE_EOFBLOCKS))
3715                 return 0;
3716
3717         depth = ext_depth(inode);
3718         eh = path[depth].p_hdr;
3719
3720         /*
3721          * We're going to remove EOFBLOCKS_FL entirely in future so we
3722          * do not care for this case anymore. Simply remove the flag
3723          * if there are no extents.
3724          */
3725         if (unlikely(!eh->eh_entries))
3726                 goto out;
3727         last_ex = EXT_LAST_EXTENT(eh);
3728         /*
3729          * We should clear the EOFBLOCKS_FL flag if we are writing the
3730          * last block in the last extent in the file.  We test this by
3731          * first checking to see if the caller to
3732          * ext4_ext_get_blocks() was interested in the last block (or
3733          * a block beyond the last block) in the current extent.  If
3734          * this turns out to be false, we can bail out from this
3735          * function immediately.
3736          */
3737         if (lblk + len < le32_to_cpu(last_ex->ee_block) +
3738             ext4_ext_get_actual_len(last_ex))
3739                 return 0;
3740         /*
3741          * If the caller does appear to be planning to write at or
3742          * beyond the end of the current extent, we then test to see
3743          * if the current extent is the last extent in the file, by
3744          * checking to make sure it was reached via the rightmost node
3745          * at each level of the tree.
3746          */
3747         for (i = depth-1; i >= 0; i--)
3748                 if (path[i].p_idx != EXT_LAST_INDEX(path[i].p_hdr))
3749                         return 0;
3750 out:
3751         ext4_clear_inode_flag(inode, EXT4_INODE_EOFBLOCKS);
3752         return ext4_mark_inode_dirty(handle, inode);
3753 }
3754
3755 /**
3756  * ext4_find_delalloc_range: find delayed allocated block in the given range.
3757  *
3758  * Return 1 if there is a delalloc block in the range, otherwise 0.
3759  */
3760 int ext4_find_delalloc_range(struct inode *inode,
3761                              ext4_lblk_t lblk_start,
3762                              ext4_lblk_t lblk_end)
3763 {
3764         struct extent_status es;
3765
3766         ext4_es_find_delayed_extent_range(inode, lblk_start, lblk_end, &es);
3767         if (es.es_len == 0)
3768                 return 0; /* there is no delay extent in this tree */
3769         else if (es.es_lblk <= lblk_start &&
3770                  lblk_start < es.es_lblk + es.es_len)
3771                 return 1;
3772         else if (lblk_start <= es.es_lblk && es.es_lblk <= lblk_end)
3773                 return 1;
3774         else
3775                 return 0;
3776 }
3777
3778 int ext4_find_delalloc_cluster(struct inode *inode, ext4_lblk_t lblk)
3779 {
3780         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
3781         ext4_lblk_t lblk_start, lblk_end;
3782         lblk_start = lblk & (~(sbi->s_cluster_ratio - 1));
3783         lblk_end = lblk_start + sbi->s_cluster_ratio - 1;
3784
3785         return ext4_find_delalloc_range(inode, lblk_start, lblk_end);
3786 }
3787
3788 /**
3789  * Determines how many complete clusters (out of those specified by the 'map')
3790  * are under delalloc and were reserved quota for.
3791  * This function is called when we are writing out the blocks that were
3792  * originally written with their allocation delayed, but then the space was
3793  * allocated using fallocate() before the delayed allocation could be resolved.
3794  * The cases to look for are:
3795  * ('=' indicated delayed allocated blocks
3796  *  '-' indicates non-delayed allocated blocks)
3797  * (a) partial clusters towards beginning and/or end outside of allocated range
3798  *     are not delalloc'ed.
3799  *      Ex:
3800  *      |----c---=|====c====|====c====|===-c----|
3801  *               |++++++ allocated ++++++|
3802  *      ==> 4 complete clusters in above example
3803  *
3804  * (b) partial cluster (outside of allocated range) towards either end is
3805  *     marked for delayed allocation. In this case, we will exclude that
3806  *     cluster.
3807  *      Ex:
3808  *      |----====c========|========c========|
3809  *           |++++++ allocated ++++++|
3810  *      ==> 1 complete clusters in above example
3811  *
3812  *      Ex:
3813  *      |================c================|
3814  *            |++++++ allocated ++++++|
3815  *      ==> 0 complete clusters in above example
3816  *
3817  * The ext4_da_update_reserve_space will be called only if we
3818  * determine here that there were some "entire" clusters that span
3819  * this 'allocated' range.
3820  * In the non-bigalloc case, this function will just end up returning num_blks
3821  * without ever calling ext4_find_delalloc_range.
3822  */
3823 static unsigned int
3824 get_reserved_cluster_alloc(struct inode *inode, ext4_lblk_t lblk_start,
3825                            unsigned int num_blks)
3826 {
3827         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
3828         ext4_lblk_t alloc_cluster_start, alloc_cluster_end;
3829         ext4_lblk_t lblk_from, lblk_to, c_offset;
3830         unsigned int allocated_clusters = 0;
3831
3832         alloc_cluster_start = EXT4_B2C(sbi, lblk_start);
3833         alloc_cluster_end = EXT4_B2C(sbi, lblk_start + num_blks - 1);
3834
3835         /* max possible clusters for this allocation */
3836         allocated_clusters = alloc_cluster_end - alloc_cluster_start + 1;
3837
3838         trace_ext4_get_reserved_cluster_alloc(inode, lblk_start, num_blks);
3839
3840         /* Check towards left side */
3841         c_offset = lblk_start & (sbi->s_cluster_ratio - 1);
3842         if (c_offset) {
3843                 lblk_from = lblk_start & (~(sbi->s_cluster_ratio - 1));
3844                 lblk_to = lblk_from + c_offset - 1;
3845
3846                 if (ext4_find_delalloc_range(inode, lblk_from, lblk_to))
3847                         allocated_clusters--;
3848         }
3849
3850         /* Now check towards right. */
3851         c_offset = (lblk_start + num_blks) & (sbi->s_cluster_ratio - 1);
3852         if (allocated_clusters && c_offset) {
3853                 lblk_from = lblk_start + num_blks;
3854                 lblk_to = lblk_from + (sbi->s_cluster_ratio - c_offset) - 1;
3855
3856                 if (ext4_find_delalloc_range(inode, lblk_from, lblk_to))
3857                         allocated_clusters--;
3858         }
3859
3860         return allocated_clusters;
3861 }
3862
3863 static int
3864 ext4_ext_handle_uninitialized_extents(handle_t *handle, struct inode *inode,
3865                         struct ext4_map_blocks *map,
3866                         struct ext4_ext_path *path, int flags,
3867                         unsigned int allocated, ext4_fsblk_t newblock)
3868 {
3869         int ret = 0;
3870         int err = 0;
3871         ext4_io_end_t *io = ext4_inode_aio(inode);
3872
3873         ext_debug("ext4_ext_handle_uninitialized_extents: inode %lu, logical "
3874                   "block %llu, max_blocks %u, flags %x, allocated %u\n",
3875                   inode->i_ino, (unsigned long long)map->m_lblk, map->m_len,
3876                   flags, allocated);
3877         ext4_ext_show_leaf(inode, path);
3878
3879         /*
3880          * When writing into uninitialized space, we should not fail to
3881          * allocate metadata blocks for the new extent block if needed.
3882          */
3883         flags |= EXT4_GET_BLOCKS_METADATA_NOFAIL;
3884
3885         trace_ext4_ext_handle_uninitialized_extents(inode, map, flags,
3886                                                     allocated, newblock);
3887
3888         /* get_block() before submit the IO, split the extent */
3889         if ((flags & EXT4_GET_BLOCKS_PRE_IO)) {
3890                 ret = ext4_split_unwritten_extents(handle, inode, map,
3891                                                    path, flags);
3892                 if (ret <= 0)
3893                         goto out;
3894                 /*
3895                  * Flag the inode(non aio case) or end_io struct (aio case)
3896                  * that this IO needs to conversion to written when IO is
3897                  * completed
3898                  */
3899                 if (io)
3900                         ext4_set_io_unwritten_flag(inode, io);
3901                 else
3902                         ext4_set_inode_state(inode, EXT4_STATE_DIO_UNWRITTEN);
3903                 map->m_flags |= EXT4_MAP_UNWRITTEN;
3904                 if (ext4_should_dioread_nolock(inode))
3905                         map->m_flags |= EXT4_MAP_UNINIT;
3906                 goto out;
3907         }
3908         /* IO end_io complete, convert the filled extent to written */
3909         if ((flags & EXT4_GET_BLOCKS_CONVERT)) {
3910                 ret = ext4_convert_unwritten_extents_endio(handle, inode, map,
3911                                                         path);
3912                 if (ret >= 0) {
3913                         ext4_update_inode_fsync_trans(handle, inode, 1);
3914                         err = check_eofblocks_fl(handle, inode, map->m_lblk,
3915                                                  path, map->m_len);
3916                 } else
3917                         err = ret;
3918                 map->m_flags |= EXT4_MAP_MAPPED;
3919                 if (allocated > map->m_len)
3920                         allocated = map->m_len;
3921                 map->m_len = allocated;
3922                 goto out2;
3923         }
3924         /* buffered IO case */
3925         /*
3926          * repeat fallocate creation request
3927          * we already have an unwritten extent
3928          */
3929         if (flags & EXT4_GET_BLOCKS_UNINIT_EXT) {
3930                 map->m_flags |= EXT4_MAP_UNWRITTEN;
3931                 goto map_out;
3932         }
3933
3934         /* buffered READ or buffered write_begin() lookup */
3935         if ((flags & EXT4_GET_BLOCKS_CREATE) == 0) {
3936                 /*
3937                  * We have blocks reserved already.  We
3938                  * return allocated blocks so that delalloc
3939                  * won't do block reservation for us.  But
3940                  * the buffer head will be unmapped so that
3941                  * a read from the block returns 0s.
3942                  */
3943                 map->m_flags |= EXT4_MAP_UNWRITTEN;
3944                 goto out1;
3945         }
3946
3947         /* buffered write, writepage time, convert*/
3948         ret = ext4_ext_convert_to_initialized(handle, inode, map, path, flags);
3949         if (ret >= 0)
3950                 ext4_update_inode_fsync_trans(handle, inode, 1);
3951 out:
3952         if (ret <= 0) {
3953                 err = ret;
3954                 goto out2;
3955         } else
3956                 allocated = ret;
3957         map->m_flags |= EXT4_MAP_NEW;
3958         /*
3959          * if we allocated more blocks than requested
3960          * we need to make sure we unmap the extra block
3961          * allocated. The actual needed block will get
3962          * unmapped later when we find the buffer_head marked
3963          * new.
3964          */
3965         if (allocated > map->m_len) {
3966                 unmap_underlying_metadata_blocks(inode->i_sb->s_bdev,
3967                                         newblock + map->m_len,
3968                                         allocated - map->m_len);
3969                 allocated = map->m_len;
3970         }
3971         map->m_len = allocated;
3972
3973         /*
3974          * If we have done fallocate with the offset that is already
3975          * delayed allocated, we would have block reservation
3976          * and quota reservation done in the delayed write path.
3977          * But fallocate would have already updated quota and block
3978          * count for this offset. So cancel these reservation
3979          */
3980         if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE) {
3981                 unsigned int reserved_clusters;
3982                 reserved_clusters = get_reserved_cluster_alloc(inode,
3983                                 map->m_lblk, map->m_len);
3984                 if (reserved_clusters)
3985                         ext4_da_update_reserve_space(inode,
3986                                                      reserved_clusters,
3987                                                      0);
3988         }
3989
3990 map_out:
3991         map->m_flags |= EXT4_MAP_MAPPED;
3992         if ((flags & EXT4_GET_BLOCKS_KEEP_SIZE) == 0) {
3993                 err = check_eofblocks_fl(handle, inode, map->m_lblk, path,
3994                                          map->m_len);
3995                 if (err < 0)
3996                         goto out2;
3997         }
3998 out1:
3999         if (allocated > map->m_len)
4000                 allocated = map->m_len;
4001         ext4_ext_show_leaf(inode, path);
4002         map->m_pblk = newblock;
4003         map->m_len = allocated;
4004 out2:
4005         if (path) {
4006                 ext4_ext_drop_refs(path);
4007                 kfree(path);
4008         }
4009         return err ? err : allocated;
4010 }
4011
4012 /*
4013  * get_implied_cluster_alloc - check to see if the requested
4014  * allocation (in the map structure) overlaps with a cluster already
4015  * allocated in an extent.
4016  *      @sb     The filesystem superblock structure
4017  *      @map    The requested lblk->pblk mapping
4018  *      @ex     The extent structure which might contain an implied
4019  *                      cluster allocation
4020  *
4021  * This function is called by ext4_ext_map_blocks() after we failed to
4022  * find blocks that were already in the inode's extent tree.  Hence,
4023  * we know that the beginning of the requested region cannot overlap
4024  * the extent from the inode's extent tree.  There are three cases we
4025  * want to catch.  The first is this case:
4026  *
4027  *               |--- cluster # N--|
4028  *    |--- extent ---|  |---- requested region ---|
4029  *                      |==========|
4030  *
4031  * The second case that we need to test for is this one:
4032  *
4033  *   |--------- cluster # N ----------------|
4034  *         |--- requested region --|   |------- extent ----|
4035  *         |=======================|
4036  *
4037  * The third case is when the requested region lies between two extents
4038  * within the same cluster:
4039  *          |------------- cluster # N-------------|
4040  * |----- ex -----|                  |---- ex_right ----|
4041  *                  |------ requested region ------|
4042  *                  |================|
4043  *
4044  * In each of the above cases, we need to set the map->m_pblk and
4045  * map->m_len so it corresponds to the return the extent labelled as
4046  * "|====|" from cluster #N, since it is already in use for data in
4047  * cluster EXT4_B2C(sbi, map->m_lblk).  We will then return 1 to
4048  * signal to ext4_ext_map_blocks() that map->m_pblk should be treated
4049  * as a new "allocated" block region.  Otherwise, we will return 0 and
4050  * ext4_ext_map_blocks() will then allocate one or more new clusters
4051  * by calling ext4_mb_new_blocks().
4052  */
4053 static int get_implied_cluster_alloc(struct super_block *sb,
4054                                      struct ext4_map_blocks *map,
4055                                      struct ext4_extent *ex,
4056                                      struct ext4_ext_path *path)
4057 {
4058         struct ext4_sb_info *sbi = EXT4_SB(sb);
4059         ext4_lblk_t c_offset = map->m_lblk & (sbi->s_cluster_ratio-1);
4060         ext4_lblk_t ex_cluster_start, ex_cluster_end;
4061         ext4_lblk_t rr_cluster_start;
4062         ext4_lblk_t ee_block = le32_to_cpu(ex->ee_block);
4063         ext4_fsblk_t ee_start = ext4_ext_pblock(ex);
4064         unsigned short ee_len = ext4_ext_get_actual_len(ex);
4065
4066         /* The extent passed in that we are trying to match */
4067         ex_cluster_start = EXT4_B2C(sbi, ee_block);
4068         ex_cluster_end = EXT4_B2C(sbi, ee_block + ee_len - 1);
4069
4070         /* The requested region passed into ext4_map_blocks() */
4071         rr_cluster_start = EXT4_B2C(sbi, map->m_lblk);
4072
4073         if ((rr_cluster_start == ex_cluster_end) ||
4074             (rr_cluster_start == ex_cluster_start)) {
4075                 if (rr_cluster_start == ex_cluster_end)
4076                         ee_start += ee_len - 1;
4077                 map->m_pblk = (ee_start & ~(sbi->s_cluster_ratio - 1)) +
4078                         c_offset;
4079                 map->m_len = min(map->m_len,
4080                                  (unsigned) sbi->s_cluster_ratio - c_offset);
4081                 /*
4082                  * Check for and handle this case:
4083                  *
4084                  *   |--------- cluster # N-------------|
4085                  *                     |------- extent ----|
4086                  *         |--- requested region ---|
4087                  *         |===========|
4088                  */
4089
4090                 if (map->m_lblk < ee_block)
4091                         map->m_len = min(map->m_len, ee_block - map->m_lblk);
4092
4093                 /*
4094                  * Check for the case where there is already another allocated
4095                  * block to the right of 'ex' but before the end of the cluster.
4096                  *
4097                  *          |------------- cluster # N-------------|
4098                  * |----- ex -----|                  |---- ex_right ----|
4099                  *                  |------ requested region ------|
4100                  *                  |================|
4101                  */
4102                 if (map->m_lblk > ee_block) {
4103                         ext4_lblk_t next = ext4_ext_next_allocated_block(path);
4104                         map->m_len = min(map->m_len, next - map->m_lblk);
4105                 }
4106
4107                 trace_ext4_get_implied_cluster_alloc_exit(sb, map, 1);
4108                 return 1;
4109         }
4110
4111         trace_ext4_get_implied_cluster_alloc_exit(sb, map, 0);
4112         return 0;
4113 }
4114
4115
4116 /*
4117  * Block allocation/map/preallocation routine for extents based files
4118  *
4119  *
4120  * Need to be called with
4121  * down_read(&EXT4_I(inode)->i_data_sem) if not allocating file system block
4122  * (ie, create is zero). Otherwise down_write(&EXT4_I(inode)->i_data_sem)
4123  *
4124  * return > 0, number of of blocks already mapped/allocated
4125  *          if create == 0 and these are pre-allocated blocks
4126  *              buffer head is unmapped
4127  *          otherwise blocks are mapped
4128  *
4129  * return = 0, if plain look up failed (blocks have not been allocated)
4130  *          buffer head is unmapped
4131  *
4132  * return < 0, error case.
4133  */
4134 int ext4_ext_map_blocks(handle_t *handle, struct inode *inode,
4135                         struct ext4_map_blocks *map, int flags)
4136 {
4137         struct ext4_ext_path *path = NULL;
4138         struct ext4_extent newex, *ex, *ex2;
4139         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
4140         ext4_fsblk_t newblock = 0;
4141         int free_on_err = 0, err = 0, depth;
4142         unsigned int allocated = 0, offset = 0;
4143         unsigned int allocated_clusters = 0;
4144         struct ext4_allocation_request ar;
4145         ext4_io_end_t *io = ext4_inode_aio(inode);
4146         ext4_lblk_t cluster_offset;
4147         int set_unwritten = 0;
4148
4149         ext_debug("blocks %u/%u requested for inode %lu\n",
4150                   map->m_lblk, map->m_len, inode->i_ino);
4151         trace_ext4_ext_map_blocks_enter(inode, map->m_lblk, map->m_len, flags);
4152
4153         /* find extent for this block */
4154         path = ext4_ext_find_extent(inode, map->m_lblk, NULL, 0);
4155         if (IS_ERR(path)) {
4156                 err = PTR_ERR(path);
4157                 path = NULL;
4158                 goto out2;
4159         }
4160
4161         depth = ext_depth(inode);
4162
4163         /*
4164          * consistent leaf must not be empty;
4165          * this situation is possible, though, _during_ tree modification;
4166          * this is why assert can't be put in ext4_ext_find_extent()
4167          */
4168         if (unlikely(path[depth].p_ext == NULL && depth != 0)) {
4169                 EXT4_ERROR_INODE(inode, "bad extent address "
4170                                  "lblock: %lu, depth: %d pblock %lld",
4171                                  (unsigned long) map->m_lblk, depth,
4172                                  path[depth].p_block);
4173                 err = -EIO;
4174                 goto out2;
4175         }
4176
4177         ex = path[depth].p_ext;
4178         if (ex) {
4179                 ext4_lblk_t ee_block = le32_to_cpu(ex->ee_block);
4180                 ext4_fsblk_t ee_start = ext4_ext_pblock(ex);
4181                 unsigned short ee_len;
4182
4183                 /*
4184                  * Uninitialized extents are treated as holes, except that
4185                  * we split out initialized portions during a write.
4186                  */
4187                 ee_len = ext4_ext_get_actual_len(ex);
4188
4189                 trace_ext4_ext_show_extent(inode, ee_block, ee_start, ee_len);
4190
4191                 /* if found extent covers block, simply return it */
4192                 if (in_range(map->m_lblk, ee_block, ee_len)) {
4193                         newblock = map->m_lblk - ee_block + ee_start;
4194                         /* number of remaining blocks in the extent */
4195                         allocated = ee_len - (map->m_lblk - ee_block);
4196                         ext_debug("%u fit into %u:%d -> %llu\n", map->m_lblk,
4197                                   ee_block, ee_len, newblock);
4198
4199                         if (!ext4_ext_is_uninitialized(ex))
4200                                 goto out;
4201
4202                         allocated = ext4_ext_handle_uninitialized_extents(
4203                                 handle, inode, map, path, flags,
4204                                 allocated, newblock);
4205                         goto out3;
4206                 }
4207         }
4208
4209         if ((sbi->s_cluster_ratio > 1) &&
4210             ext4_find_delalloc_cluster(inode, map->m_lblk))
4211                 map->m_flags |= EXT4_MAP_FROM_CLUSTER;
4212
4213         /*
4214          * requested block isn't allocated yet;
4215          * we couldn't try to create block if create flag is zero
4216          */
4217         if ((flags & EXT4_GET_BLOCKS_CREATE) == 0) {
4218                 /*
4219                  * put just found gap into cache to speed up
4220                  * subsequent requests
4221                  */
4222                 if ((flags & EXT4_GET_BLOCKS_NO_PUT_HOLE) == 0)
4223                         ext4_ext_put_gap_in_cache(inode, path, map->m_lblk);
4224                 goto out2;
4225         }
4226
4227         /*
4228          * Okay, we need to do block allocation.
4229          */
4230         map->m_flags &= ~EXT4_MAP_FROM_CLUSTER;
4231         newex.ee_block = cpu_to_le32(map->m_lblk);
4232         cluster_offset = map->m_lblk & (sbi->s_cluster_ratio-1);
4233
4234         /*
4235          * If we are doing bigalloc, check to see if the extent returned
4236          * by ext4_ext_find_extent() implies a cluster we can use.
4237          */
4238         if (cluster_offset && ex &&
4239             get_implied_cluster_alloc(inode->i_sb, map, ex, path)) {
4240                 ar.len = allocated = map->m_len;
4241                 newblock = map->m_pblk;
4242                 map->m_flags |= EXT4_MAP_FROM_CLUSTER;
4243                 goto got_allocated_blocks;
4244         }
4245
4246         /* find neighbour allocated blocks */
4247         ar.lleft = map->m_lblk;
4248         err = ext4_ext_search_left(inode, path, &ar.lleft, &ar.pleft);
4249         if (err)
4250                 goto out2;
4251         ar.lright = map->m_lblk;
4252         ex2 = NULL;
4253         err = ext4_ext_search_right(inode, path, &ar.lright, &ar.pright, &ex2);
4254         if (err)
4255                 goto out2;
4256
4257         /* Check if the extent after searching to the right implies a
4258          * cluster we can use. */
4259         if ((sbi->s_cluster_ratio > 1) && ex2 &&
4260             get_implied_cluster_alloc(inode->i_sb, map, ex2, path)) {
4261                 ar.len = allocated = map->m_len;
4262                 newblock = map->m_pblk;
4263                 map->m_flags |= EXT4_MAP_FROM_CLUSTER;
4264                 goto got_allocated_blocks;
4265         }
4266
4267         /*
4268          * See if request is beyond maximum number of blocks we can have in
4269          * a single extent. For an initialized extent this limit is
4270          * EXT_INIT_MAX_LEN and for an uninitialized extent this limit is
4271          * EXT_UNINIT_MAX_LEN.
4272          */
4273         if (map->m_len > EXT_INIT_MAX_LEN &&
4274             !(flags & EXT4_GET_BLOCKS_UNINIT_EXT))
4275                 map->m_len = EXT_INIT_MAX_LEN;
4276         else if (map->m_len > EXT_UNINIT_MAX_LEN &&
4277                  (flags & EXT4_GET_BLOCKS_UNINIT_EXT))
4278                 map->m_len = EXT_UNINIT_MAX_LEN;
4279
4280         /* Check if we can really insert (m_lblk)::(m_lblk + m_len) extent */
4281         newex.ee_len = cpu_to_le16(map->m_len);
4282         err = ext4_ext_check_overlap(sbi, inode, &newex, path);
4283         if (err)
4284                 allocated = ext4_ext_get_actual_len(&newex);
4285         else
4286                 allocated = map->m_len;
4287
4288         /* allocate new block */
4289         ar.inode = inode;
4290         ar.goal = ext4_ext_find_goal(inode, path, map->m_lblk);
4291         ar.logical = map->m_lblk;
4292         /*
4293          * We calculate the offset from the beginning of the cluster
4294          * for the logical block number, since when we allocate a
4295          * physical cluster, the physical block should start at the
4296          * same offset from the beginning of the cluster.  This is
4297          * needed so that future calls to get_implied_cluster_alloc()
4298          * work correctly.
4299          */
4300         offset = map->m_lblk & (sbi->s_cluster_ratio - 1);
4301         ar.len = EXT4_NUM_B2C(sbi, offset+allocated);
4302         ar.goal -= offset;
4303         ar.logical -= offset;
4304         if (S_ISREG(inode->i_mode))
4305                 ar.flags = EXT4_MB_HINT_DATA;
4306         else
4307                 /* disable in-core preallocation for non-regular files */
4308                 ar.flags = 0;
4309         if (flags & EXT4_GET_BLOCKS_NO_NORMALIZE)
4310                 ar.flags |= EXT4_MB_HINT_NOPREALLOC;
4311         newblock = ext4_mb_new_blocks(handle, &ar, &err);
4312         if (!newblock)
4313                 goto out2;
4314         ext_debug("allocate new block: goal %llu, found %llu/%u\n",
4315                   ar.goal, newblock, allocated);
4316         free_on_err = 1;
4317         allocated_clusters = ar.len;
4318         ar.len = EXT4_C2B(sbi, ar.len) - offset;
4319         if (ar.len > allocated)
4320                 ar.len = allocated;
4321
4322 got_allocated_blocks:
4323         /* try to insert new extent into found leaf and return */
4324         ext4_ext_store_pblock(&newex, newblock + offset);
4325         newex.ee_len = cpu_to_le16(ar.len);
4326         /* Mark uninitialized */
4327         if (flags & EXT4_GET_BLOCKS_UNINIT_EXT){
4328                 ext4_ext_mark_uninitialized(&newex);
4329                 map->m_flags |= EXT4_MAP_UNWRITTEN;
4330                 /*
4331                  * io_end structure was created for every IO write to an
4332                  * uninitialized extent. To avoid unnecessary conversion,
4333                  * here we flag the IO that really needs the conversion.
4334                  * For non asycn direct IO case, flag the inode state
4335                  * that we need to perform conversion when IO is done.
4336                  */
4337                 if ((flags & EXT4_GET_BLOCKS_PRE_IO))
4338                         set_unwritten = 1;
4339                 if (ext4_should_dioread_nolock(inode))
4340                         map->m_flags |= EXT4_MAP_UNINIT;
4341         }
4342
4343         err = 0;
4344         if ((flags & EXT4_GET_BLOCKS_KEEP_SIZE) == 0)
4345                 err = check_eofblocks_fl(handle, inode, map->m_lblk,
4346                                          path, ar.len);
4347         if (!err)
4348                 err = ext4_ext_insert_extent(handle, inode, path,
4349                                              &newex, flags);
4350
4351         if (!err && set_unwritten) {
4352                 if (io)
4353                         ext4_set_io_unwritten_flag(inode, io);
4354                 else
4355                         ext4_set_inode_state(inode,
4356                                              EXT4_STATE_DIO_UNWRITTEN);
4357         }
4358
4359         if (err && free_on_err) {
4360                 int fb_flags = flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE ?
4361                         EXT4_FREE_BLOCKS_NO_QUOT_UPDATE : 0;
4362                 /* free data blocks we just allocated */
4363                 /* not a good idea to call discard here directly,
4364                  * but otherwise we'd need to call it every free() */
4365                 ext4_discard_preallocations(inode);
4366                 ext4_free_blocks(handle, inode, NULL, newblock,
4367                                  EXT4_C2B(sbi, allocated_clusters), fb_flags);
4368                 goto out2;
4369         }
4370
4371         /* previous routine could use block we allocated */
4372         newblock = ext4_ext_pblock(&newex);
4373         allocated = ext4_ext_get_actual_len(&newex);
4374         if (allocated > map->m_len)
4375                 allocated = map->m_len;
4376         map->m_flags |= EXT4_MAP_NEW;
4377
4378         /*
4379          * Update reserved blocks/metadata blocks after successful
4380          * block allocation which had been deferred till now.
4381          */
4382         if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE) {
4383                 unsigned int reserved_clusters;
4384                 /*
4385                  * Check how many clusters we had reserved this allocated range
4386                  */
4387                 reserved_clusters = get_reserved_cluster_alloc(inode,
4388                                                 map->m_lblk, allocated);
4389                 if (map->m_flags & EXT4_MAP_FROM_CLUSTER) {
4390                         if (reserved_clusters) {
4391                                 /*
4392                                  * We have clusters reserved for this range.
4393                                  * But since we are not doing actual allocation
4394                                  * and are simply using blocks from previously
4395                                  * allocated cluster, we should release the
4396                                  * reservation and not claim quota.
4397                                  */
4398                                 ext4_da_update_reserve_space(inode,
4399                                                 reserved_clusters, 0);
4400                         }
4401                 } else {
4402                         BUG_ON(allocated_clusters < reserved_clusters);
4403                         if (reserved_clusters < allocated_clusters) {
4404                                 struct ext4_inode_info *ei = EXT4_I(inode);
4405                                 int reservation = allocated_clusters -
4406                                                   reserved_clusters;
4407                                 /*
4408                                  * It seems we claimed few clusters outside of
4409                                  * the range of this allocation. We should give
4410                                  * it back to the reservation pool. This can
4411                                  * happen in the following case:
4412                                  *
4413                                  * * Suppose s_cluster_ratio is 4 (i.e., each
4414                                  *   cluster has 4 blocks. Thus, the clusters
4415                                  *   are [0-3],[4-7],[8-11]...
4416                                  * * First comes delayed allocation write for
4417                                  *   logical blocks 10 & 11. Since there were no
4418                                  *   previous delayed allocated blocks in the
4419                                  *   range [8-11], we would reserve 1 cluster
4420                                  *   for this write.
4421                                  * * Next comes write for logical blocks 3 to 8.
4422                                  *   In this case, we will reserve 2 clusters
4423                                  *   (for [0-3] and [4-7]; and not for [8-11] as
4424                                  *   that range has a delayed allocated blocks.
4425                                  *   Thus total reserved clusters now becomes 3.
4426                                  * * Now, during the delayed allocation writeout
4427                                  *   time, we will first write blocks [3-8] and
4428                                  *   allocate 3 clusters for writing these
4429                                  *   blocks. Also, we would claim all these
4430                                  *   three clusters above.
4431                                  * * Now when we come here to writeout the
4432                                  *   blocks [10-11], we would expect to claim
4433                                  *   the reservation of 1 cluster we had made
4434                                  *   (and we would claim it since there are no
4435                                  *   more delayed allocated blocks in the range
4436                                  *   [8-11]. But our reserved cluster count had
4437                                  *   already gone to 0.
4438                                  *
4439                                  *   Thus, at the step 4 above when we determine
4440                                  *   that there are still some unwritten delayed
4441                                  *   allocated blocks outside of our current
4442                                  *   block range, we should increment the
4443                                  *   reserved clusters count so that when the
4444                                  *   remaining blocks finally gets written, we
4445                                  *   could claim them.
4446                                  */
4447                                 dquot_reserve_block(inode,
4448                                                 EXT4_C2B(sbi, reservation));
4449                                 spin_lock(&ei->i_block_reservation_lock);
4450                                 ei->i_reserved_data_blocks += reservation;
4451                                 spin_unlock(&ei->i_block_reservation_lock);
4452                         }
4453                         /*
4454                          * We will claim quota for all newly allocated blocks.
4455                          * We're updating the reserved space *after* the
4456                          * correction above so we do not accidentally free
4457                          * all the metadata reservation because we might
4458                          * actually need it later on.
4459                          */
4460                         ext4_da_update_reserve_space(inode, allocated_clusters,
4461                                                         1);
4462                 }
4463         }
4464
4465         /*
4466          * Cache the extent and update transaction to commit on fdatasync only
4467          * when it is _not_ an uninitialized extent.
4468          */
4469         if ((flags & EXT4_GET_BLOCKS_UNINIT_EXT) == 0)
4470                 ext4_update_inode_fsync_trans(handle, inode, 1);
4471         else
4472                 ext4_update_inode_fsync_trans(handle, inode, 0);
4473 out:
4474         if (allocated > map->m_len)
4475                 allocated = map->m_len;
4476         ext4_ext_show_leaf(inode, path);
4477         map->m_flags |= EXT4_MAP_MAPPED;
4478         map->m_pblk = newblock;
4479         map->m_len = allocated;
4480 out2:
4481         if (path) {
4482                 ext4_ext_drop_refs(path);
4483                 kfree(path);
4484         }
4485
4486 out3:
4487         trace_ext4_ext_map_blocks_exit(inode, flags, map,
4488                                        err ? err : allocated);
4489         ext4_es_lru_add(inode);
4490         return err ? err : allocated;
4491 }
4492
4493 void ext4_ext_truncate(handle_t *handle, struct inode *inode)
4494 {
4495         struct super_block *sb = inode->i_sb;
4496         ext4_lblk_t last_block;
4497         int err = 0;
4498
4499         /*
4500          * TODO: optimization is possible here.
4501          * Probably we need not scan at all,
4502          * because page truncation is enough.
4503          */
4504
4505         /* we have to know where to truncate from in crash case */
4506         EXT4_I(inode)->i_disksize = inode->i_size;
4507         ext4_mark_inode_dirty(handle, inode);
4508
4509         last_block = (inode->i_size + sb->s_blocksize - 1)
4510                         >> EXT4_BLOCK_SIZE_BITS(sb);
4511 retry:
4512         err = ext4_es_remove_extent(inode, last_block,
4513                                     EXT_MAX_BLOCKS - last_block);
4514         if (err == -ENOMEM) {
4515                 cond_resched();
4516                 congestion_wait(BLK_RW_ASYNC, HZ/50);
4517                 goto retry;
4518         }
4519         if (err) {
4520                 ext4_std_error(inode->i_sb, err);
4521                 return;
4522         }
4523         err = ext4_ext_remove_space(inode, last_block, EXT_MAX_BLOCKS - 1);
4524         ext4_std_error(inode->i_sb, err);
4525 }
4526
4527 static void ext4_falloc_update_inode(struct inode *inode,
4528                                 int mode, loff_t new_size, int update_ctime)
4529 {
4530         struct timespec now;
4531
4532         if (update_ctime) {
4533                 now = current_fs_time(inode->i_sb);
4534                 if (!timespec_equal(&inode->i_ctime, &now))
4535                         inode->i_ctime = now;
4536         }
4537         /*
4538          * Update only when preallocation was requested beyond
4539          * the file size.
4540          */
4541         if (!(mode & FALLOC_FL_KEEP_SIZE)) {
4542                 if (new_size > i_size_read(inode))
4543                         i_size_write(inode, new_size);
4544                 if (new_size > EXT4_I(inode)->i_disksize)
4545                         ext4_update_i_disksize(inode, new_size);
4546         } else {
4547                 /*
4548                  * Mark that we allocate beyond EOF so the subsequent truncate
4549                  * can proceed even if the new size is the same as i_size.
4550                  */
4551                 if (new_size > i_size_read(inode))
4552                         ext4_set_inode_flag(inode, EXT4_INODE_EOFBLOCKS);
4553         }
4554
4555 }
4556
4557 /*
4558  * preallocate space for a file. This implements ext4's fallocate file
4559  * operation, which gets called from sys_fallocate system call.
4560  * For block-mapped files, posix_fallocate should fall back to the method
4561  * of writing zeroes to the required new blocks (the same behavior which is
4562  * expected for file systems which do not support fallocate() system call).
4563  */
4564 long ext4_fallocate(struct file *file, int mode, loff_t offset, loff_t len)
4565 {
4566         struct inode *inode = file_inode(file);
4567         handle_t *handle;
4568         loff_t new_size;
4569         unsigned int max_blocks;
4570         int ret = 0;
4571         int ret2 = 0;
4572         int retries = 0;
4573         int flags;
4574         struct ext4_map_blocks map;
4575         unsigned int credits, blkbits = inode->i_blkbits;
4576
4577         /* Return error if mode is not supported */
4578         if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE))
4579                 return -EOPNOTSUPP;
4580
4581         if (mode & FALLOC_FL_PUNCH_HOLE)
4582                 return ext4_punch_hole(inode, offset, len);
4583
4584         ret = ext4_convert_inline_data(inode);
4585         if (ret)
4586                 return ret;
4587
4588         /*
4589          * currently supporting (pre)allocate mode for extent-based
4590          * files _only_
4591          */
4592         if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
4593                 return -EOPNOTSUPP;
4594
4595         trace_ext4_fallocate_enter(inode, offset, len, mode);
4596         map.m_lblk = offset >> blkbits;
4597         /*
4598          * We can't just convert len to max_blocks because
4599          * If blocksize = 4096 offset = 3072 and len = 2048
4600          */
4601         max_blocks = (EXT4_BLOCK_ALIGN(len + offset, blkbits) >> blkbits)
4602                 - map.m_lblk;
4603         /*
4604          * credits to insert 1 extent into extent tree
4605          */
4606         credits = ext4_chunk_trans_blocks(inode, max_blocks);
4607         mutex_lock(&inode->i_mutex);
4608         ret = inode_newsize_ok(inode, (len + offset));
4609         if (ret) {
4610                 mutex_unlock(&inode->i_mutex);
4611                 trace_ext4_fallocate_exit(inode, offset, max_blocks, ret);
4612                 return ret;
4613         }
4614         flags = EXT4_GET_BLOCKS_CREATE_UNINIT_EXT;
4615         if (mode & FALLOC_FL_KEEP_SIZE)
4616                 flags |= EXT4_GET_BLOCKS_KEEP_SIZE;
4617         /*
4618          * Don't normalize the request if it can fit in one extent so
4619          * that it doesn't get unnecessarily split into multiple
4620          * extents.
4621          */
4622         if (len <= EXT_UNINIT_MAX_LEN << blkbits)
4623                 flags |= EXT4_GET_BLOCKS_NO_NORMALIZE;
4624
4625 retry:
4626         while (ret >= 0 && ret < max_blocks) {
4627                 map.m_lblk = map.m_lblk + ret;
4628                 map.m_len = max_blocks = max_blocks - ret;
4629                 handle = ext4_journal_start(inode, EXT4_HT_MAP_BLOCKS,
4630                                             credits);
4631                 if (IS_ERR(handle)) {
4632                         ret = PTR_ERR(handle);
4633                         break;
4634                 }
4635                 ret = ext4_map_blocks(handle, inode, &map, flags);
4636                 if (ret <= 0) {
4637 #ifdef EXT4FS_DEBUG
4638                         ext4_warning(inode->i_sb,
4639                                      "inode #%lu: block %u: len %u: "
4640                                      "ext4_ext_map_blocks returned %d",
4641                                      inode->i_ino, map.m_lblk,
4642                                      map.m_len, ret);
4643 #endif
4644                         ext4_mark_inode_dirty(handle, inode);
4645                         ret2 = ext4_journal_stop(handle);
4646                         break;
4647                 }
4648                 if ((map.m_lblk + ret) >= (EXT4_BLOCK_ALIGN(offset + len,
4649                                                 blkbits) >> blkbits))
4650                         new_size = offset + len;
4651                 else
4652                         new_size = ((loff_t) map.m_lblk + ret) << blkbits;
4653
4654                 ext4_falloc_update_inode(inode, mode, new_size,
4655                                          (map.m_flags & EXT4_MAP_NEW));
4656                 ext4_mark_inode_dirty(handle, inode);
4657                 if ((file->f_flags & O_SYNC) && ret >= max_blocks)
4658                         ext4_handle_sync(handle);
4659                 ret2 = ext4_journal_stop(handle);
4660                 if (ret2)
4661                         break;
4662         }
4663         if (ret == -ENOSPC &&
4664                         ext4_should_retry_alloc(inode->i_sb, &retries)) {
4665                 ret = 0;
4666                 goto retry;
4667         }
4668         mutex_unlock(&inode->i_mutex);
4669         trace_ext4_fallocate_exit(inode, offset, max_blocks,
4670                                 ret > 0 ? ret2 : ret);
4671         return ret > 0 ? ret2 : ret;
4672 }
4673
4674 /*
4675  * This function convert a range of blocks to written extents
4676  * The caller of this function will pass the start offset and the size.
4677  * all unwritten extents within this range will be converted to
4678  * written extents.
4679  *
4680  * This function is called from the direct IO end io call back
4681  * function, to convert the fallocated extents after IO is completed.
4682  * Returns 0 on success.
4683  */
4684 int ext4_convert_unwritten_extents(handle_t *handle, struct inode *inode,
4685                                    loff_t offset, ssize_t len)
4686 {
4687         unsigned int max_blocks;
4688         int ret = 0;
4689         int ret2 = 0;
4690         struct ext4_map_blocks map;
4691         unsigned int credits, blkbits = inode->i_blkbits;
4692
4693         map.m_lblk = offset >> blkbits;
4694         /*
4695          * We can't just convert len to max_blocks because
4696          * If blocksize = 4096 offset = 3072 and len = 2048
4697          */
4698         max_blocks = ((EXT4_BLOCK_ALIGN(len + offset, blkbits) >> blkbits) -
4699                       map.m_lblk);
4700         /*
4701          * This is somewhat ugly but the idea is clear: When transaction is
4702          * reserved, everything goes into it. Otherwise we rather start several
4703          * smaller transactions for conversion of each extent separately.
4704          */
4705         if (handle) {
4706                 handle = ext4_journal_start_reserved(handle,
4707                                                      EXT4_HT_EXT_CONVERT);
4708                 if (IS_ERR(handle))
4709                         return PTR_ERR(handle);
4710                 credits = 0;
4711         } else {
4712                 /*
4713                  * credits to insert 1 extent into extent tree
4714                  */
4715                 credits = ext4_chunk_trans_blocks(inode, max_blocks);
4716         }
4717         while (ret >= 0 && ret < max_blocks) {
4718                 map.m_lblk += ret;
4719                 map.m_len = (max_blocks -= ret);
4720                 if (credits) {
4721                         handle = ext4_journal_start(inode, EXT4_HT_MAP_BLOCKS,
4722                                                     credits);
4723                         if (IS_ERR(handle)) {
4724                                 ret = PTR_ERR(handle);
4725                                 break;
4726                         }
4727                 }
4728                 ret = ext4_map_blocks(handle, inode, &map,
4729                                       EXT4_GET_BLOCKS_IO_CONVERT_EXT);
4730                 if (ret <= 0)
4731                         ext4_warning(inode->i_sb,
4732                                      "inode #%lu: block %u: len %u: "
4733                                      "ext4_ext_map_blocks returned %d",
4734                                      inode->i_ino, map.m_lblk,
4735                                      map.m_len, ret);
4736                 ext4_mark_inode_dirty(handle, inode);
4737                 if (credits)
4738                         ret2 = ext4_journal_stop(handle);
4739                 if (ret <= 0 || ret2)
4740                         break;
4741         }
4742         if (!credits)
4743                 ret2 = ext4_journal_stop(handle);
4744         return ret > 0 ? ret2 : ret;
4745 }
4746
4747 /*
4748  * If newes is not existing extent (newes->ec_pblk equals zero) find
4749  * delayed extent at start of newes and update newes accordingly and
4750  * return start of the next delayed extent.
4751  *
4752  * If newes is existing extent (newes->ec_pblk is not equal zero)
4753  * return start of next delayed extent or EXT_MAX_BLOCKS if no delayed
4754  * extent found. Leave newes unmodified.
4755  */
4756 static int ext4_find_delayed_extent(struct inode *inode,
4757                                     struct extent_status *newes)
4758 {
4759         struct extent_status es;
4760         ext4_lblk_t block, next_del;
4761
4762         if (newes->es_pblk == 0) {
4763                 ext4_es_find_delayed_extent_range(inode, newes->es_lblk,
4764                                 newes->es_lblk + newes->es_len - 1, &es);
4765
4766                 /*
4767                  * No extent in extent-tree contains block @newes->es_pblk,
4768                  * then the block may stay in 1)a hole or 2)delayed-extent.
4769                  */
4770                 if (es.es_len == 0)
4771                         /* A hole found. */
4772                         return 0;
4773
4774                 if (es.es_lblk > newes->es_lblk) {
4775                         /* A hole found. */
4776                         newes->es_len = min(es.es_lblk - newes->es_lblk,
4777                                             newes->es_len);
4778                         return 0;
4779                 }
4780
4781                 newes->es_len = es.es_lblk + es.es_len - newes->es_lblk;
4782         }
4783
4784         block = newes->es_lblk + newes->es_len;
4785         ext4_es_find_delayed_extent_range(inode, block, EXT_MAX_BLOCKS, &es);
4786         if (es.es_len == 0)
4787                 next_del = EXT_MAX_BLOCKS;
4788         else
4789                 next_del = es.es_lblk;
4790
4791         return next_del;
4792 }
4793 /* fiemap flags we can handle specified here */
4794 #define EXT4_FIEMAP_FLAGS       (FIEMAP_FLAG_SYNC|FIEMAP_FLAG_XATTR)
4795
4796 static int ext4_xattr_fiemap(struct inode *inode,
4797                                 struct fiemap_extent_info *fieinfo)
4798 {
4799         __u64 physical = 0;
4800         __u64 length;
4801         __u32 flags = FIEMAP_EXTENT_LAST;
4802         int blockbits = inode->i_sb->s_blocksize_bits;
4803         int error = 0;
4804
4805         /* in-inode? */
4806         if (ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
4807                 struct ext4_iloc iloc;
4808                 int offset;     /* offset of xattr in inode */
4809
4810                 error = ext4_get_inode_loc(inode, &iloc);
4811                 if (error)
4812                         return error;
4813                 physical = (__u64)iloc.bh->b_blocknr << blockbits;
4814                 offset = EXT4_GOOD_OLD_INODE_SIZE +
4815                                 EXT4_I(inode)->i_extra_isize;
4816                 physical += offset;
4817                 length = EXT4_SB(inode->i_sb)->s_inode_size - offset;
4818                 flags |= FIEMAP_EXTENT_DATA_INLINE;
4819                 brelse(iloc.bh);
4820         } else { /* external block */
4821                 physical = (__u64)EXT4_I(inode)->i_file_acl << blockbits;
4822                 length = inode->i_sb->s_blocksize;
4823         }
4824
4825         if (physical)
4826                 error = fiemap_fill_next_extent(fieinfo, 0, physical,
4827                                                 length, flags);
4828         return (error < 0 ? error : 0);
4829 }
4830
4831 int ext4_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
4832                 __u64 start, __u64 len)
4833 {
4834         ext4_lblk_t start_blk;
4835         int error = 0;
4836
4837         if (ext4_has_inline_data(inode)) {
4838                 int has_inline = 1;
4839
4840                 error = ext4_inline_data_fiemap(inode, fieinfo, &has_inline);
4841
4842                 if (has_inline)
4843                         return error;
4844         }
4845
4846         if (fieinfo->fi_flags & FIEMAP_FLAG_CACHE) {
4847                 error = ext4_ext_precache(inode);
4848                 if (error)
4849                         return error;
4850         }
4851
4852         /* fallback to generic here if not in extents fmt */
4853         if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
4854                 return generic_block_fiemap(inode, fieinfo, start, len,
4855                         ext4_get_block);
4856
4857         if (fiemap_check_flags(fieinfo, EXT4_FIEMAP_FLAGS))
4858                 return -EBADR;
4859
4860         if (fieinfo->fi_flags & FIEMAP_FLAG_XATTR) {
4861                 error = ext4_xattr_fiemap(inode, fieinfo);
4862         } else {
4863                 ext4_lblk_t len_blks;
4864                 __u64 last_blk;
4865
4866                 start_blk = start >> inode->i_sb->s_blocksize_bits;
4867                 last_blk = (start + len - 1) >> inode->i_sb->s_blocksize_bits;
4868                 if (last_blk >= EXT_MAX_BLOCKS)
4869                         last_blk = EXT_MAX_BLOCKS-1;
4870                 len_blks = ((ext4_lblk_t) last_blk) - start_blk + 1;
4871
4872                 /*
4873                  * Walk the extent tree gathering extent information
4874                  * and pushing extents back to the user.
4875                  */
4876                 error = ext4_fill_fiemap_extents(inode, start_blk,
4877                                                  len_blks, fieinfo);
4878         }
4879         ext4_es_lru_add(inode);
4880         return error;
4881 }